1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Performance events core code:
4 *
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 */
10
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
57 #include <linux/task_work.h>
58
59 #include "internal.h"
60
61 #include <asm/irq_regs.h>
62
63 typedef int (*remote_function_f)(void *);
64
65 struct remote_function_call {
66 struct task_struct *p;
67 remote_function_f func;
68 void *info;
69 int ret;
70 };
71
remote_function(void * data)72 static void remote_function(void *data)
73 {
74 struct remote_function_call *tfc = data;
75 struct task_struct *p = tfc->p;
76
77 if (p) {
78 /* -EAGAIN */
79 if (task_cpu(p) != smp_processor_id())
80 return;
81
82 /*
83 * Now that we're on right CPU with IRQs disabled, we can test
84 * if we hit the right task without races.
85 */
86
87 tfc->ret = -ESRCH; /* No such (running) process */
88 if (p != current)
89 return;
90 }
91
92 tfc->ret = tfc->func(tfc->info);
93 }
94
95 /**
96 * task_function_call - call a function on the cpu on which a task runs
97 * @p: the task to evaluate
98 * @func: the function to be called
99 * @info: the function call argument
100 *
101 * Calls the function @func when the task is currently running. This might
102 * be on the current CPU, which just calls the function directly. This will
103 * retry due to any failures in smp_call_function_single(), such as if the
104 * task_cpu() goes offline concurrently.
105 *
106 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
107 */
108 static int
task_function_call(struct task_struct * p,remote_function_f func,void * info)109 task_function_call(struct task_struct *p, remote_function_f func, void *info)
110 {
111 struct remote_function_call data = {
112 .p = p,
113 .func = func,
114 .info = info,
115 .ret = -EAGAIN,
116 };
117 int ret;
118
119 for (;;) {
120 ret = smp_call_function_single(task_cpu(p), remote_function,
121 &data, 1);
122 if (!ret)
123 ret = data.ret;
124
125 if (ret != -EAGAIN)
126 break;
127
128 cond_resched();
129 }
130
131 return ret;
132 }
133
134 /**
135 * cpu_function_call - call a function on the cpu
136 * @cpu: target cpu to queue this function
137 * @func: the function to be called
138 * @info: the function call argument
139 *
140 * Calls the function @func on the remote cpu.
141 *
142 * returns: @func return value or -ENXIO when the cpu is offline
143 */
cpu_function_call(int cpu,remote_function_f func,void * info)144 static int cpu_function_call(int cpu, remote_function_f func, void *info)
145 {
146 struct remote_function_call data = {
147 .p = NULL,
148 .func = func,
149 .info = info,
150 .ret = -ENXIO, /* No such CPU */
151 };
152
153 smp_call_function_single(cpu, remote_function, &data, 1);
154
155 return data.ret;
156 }
157
perf_ctx_lock(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
160 {
161 raw_spin_lock(&cpuctx->ctx.lock);
162 if (ctx)
163 raw_spin_lock(&ctx->lock);
164 }
165
perf_ctx_unlock(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 struct perf_event_context *ctx)
168 {
169 if (ctx)
170 raw_spin_unlock(&ctx->lock);
171 raw_spin_unlock(&cpuctx->ctx.lock);
172 }
173
174 #define TASK_TOMBSTONE ((void *)-1L)
175
is_kernel_event(struct perf_event * event)176 static bool is_kernel_event(struct perf_event *event)
177 {
178 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
179 }
180
181 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
182
perf_cpu_task_ctx(void)183 struct perf_event_context *perf_cpu_task_ctx(void)
184 {
185 lockdep_assert_irqs_disabled();
186 return this_cpu_ptr(&perf_cpu_context)->task_ctx;
187 }
188
189 /*
190 * On task ctx scheduling...
191 *
192 * When !ctx->nr_events a task context will not be scheduled. This means
193 * we can disable the scheduler hooks (for performance) without leaving
194 * pending task ctx state.
195 *
196 * This however results in two special cases:
197 *
198 * - removing the last event from a task ctx; this is relatively straight
199 * forward and is done in __perf_remove_from_context.
200 *
201 * - adding the first event to a task ctx; this is tricky because we cannot
202 * rely on ctx->is_active and therefore cannot use event_function_call().
203 * See perf_install_in_context().
204 *
205 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
206 */
207
208 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
209 struct perf_event_context *, void *);
210
211 struct event_function_struct {
212 struct perf_event *event;
213 event_f func;
214 void *data;
215 };
216
event_function(void * info)217 static int event_function(void *info)
218 {
219 struct event_function_struct *efs = info;
220 struct perf_event *event = efs->event;
221 struct perf_event_context *ctx = event->ctx;
222 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
223 struct perf_event_context *task_ctx = cpuctx->task_ctx;
224 int ret = 0;
225
226 lockdep_assert_irqs_disabled();
227
228 perf_ctx_lock(cpuctx, task_ctx);
229 /*
230 * Since we do the IPI call without holding ctx->lock things can have
231 * changed, double check we hit the task we set out to hit.
232 */
233 if (ctx->task) {
234 if (ctx->task != current) {
235 ret = -ESRCH;
236 goto unlock;
237 }
238
239 /*
240 * We only use event_function_call() on established contexts,
241 * and event_function() is only ever called when active (or
242 * rather, we'll have bailed in task_function_call() or the
243 * above ctx->task != current test), therefore we must have
244 * ctx->is_active here.
245 */
246 WARN_ON_ONCE(!ctx->is_active);
247 /*
248 * And since we have ctx->is_active, cpuctx->task_ctx must
249 * match.
250 */
251 WARN_ON_ONCE(task_ctx != ctx);
252 } else {
253 WARN_ON_ONCE(&cpuctx->ctx != ctx);
254 }
255
256 efs->func(event, cpuctx, ctx, efs->data);
257 unlock:
258 perf_ctx_unlock(cpuctx, task_ctx);
259
260 return ret;
261 }
262
event_function_call(struct perf_event * event,event_f func,void * data)263 static void event_function_call(struct perf_event *event, event_f func, void *data)
264 {
265 struct perf_event_context *ctx = event->ctx;
266 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
267 struct event_function_struct efs = {
268 .event = event,
269 .func = func,
270 .data = data,
271 };
272
273 if (!event->parent) {
274 /*
275 * If this is a !child event, we must hold ctx::mutex to
276 * stabilize the event->ctx relation. See
277 * perf_event_ctx_lock().
278 */
279 lockdep_assert_held(&ctx->mutex);
280 }
281
282 if (!task) {
283 cpu_function_call(event->cpu, event_function, &efs);
284 return;
285 }
286
287 if (task == TASK_TOMBSTONE)
288 return;
289
290 again:
291 if (!task_function_call(task, event_function, &efs))
292 return;
293
294 raw_spin_lock_irq(&ctx->lock);
295 /*
296 * Reload the task pointer, it might have been changed by
297 * a concurrent perf_event_context_sched_out().
298 */
299 task = ctx->task;
300 if (task == TASK_TOMBSTONE) {
301 raw_spin_unlock_irq(&ctx->lock);
302 return;
303 }
304 if (ctx->is_active) {
305 raw_spin_unlock_irq(&ctx->lock);
306 goto again;
307 }
308 func(event, NULL, ctx, data);
309 raw_spin_unlock_irq(&ctx->lock);
310 }
311
312 /*
313 * Similar to event_function_call() + event_function(), but hard assumes IRQs
314 * are already disabled and we're on the right CPU.
315 */
event_function_local(struct perf_event * event,event_f func,void * data)316 static void event_function_local(struct perf_event *event, event_f func, void *data)
317 {
318 struct perf_event_context *ctx = event->ctx;
319 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
320 struct task_struct *task = READ_ONCE(ctx->task);
321 struct perf_event_context *task_ctx = NULL;
322
323 lockdep_assert_irqs_disabled();
324
325 if (task) {
326 if (task == TASK_TOMBSTONE)
327 return;
328
329 task_ctx = ctx;
330 }
331
332 perf_ctx_lock(cpuctx, task_ctx);
333
334 task = ctx->task;
335 if (task == TASK_TOMBSTONE)
336 goto unlock;
337
338 if (task) {
339 /*
340 * We must be either inactive or active and the right task,
341 * otherwise we're screwed, since we cannot IPI to somewhere
342 * else.
343 */
344 if (ctx->is_active) {
345 if (WARN_ON_ONCE(task != current))
346 goto unlock;
347
348 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
349 goto unlock;
350 }
351 } else {
352 WARN_ON_ONCE(&cpuctx->ctx != ctx);
353 }
354
355 func(event, cpuctx, ctx, data);
356 unlock:
357 perf_ctx_unlock(cpuctx, task_ctx);
358 }
359
360 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
361 PERF_FLAG_FD_OUTPUT |\
362 PERF_FLAG_PID_CGROUP |\
363 PERF_FLAG_FD_CLOEXEC)
364
365 /*
366 * branch priv levels that need permission checks
367 */
368 #define PERF_SAMPLE_BRANCH_PERM_PLM \
369 (PERF_SAMPLE_BRANCH_KERNEL |\
370 PERF_SAMPLE_BRANCH_HV)
371
372 enum event_type_t {
373 EVENT_FLEXIBLE = 0x1,
374 EVENT_PINNED = 0x2,
375 EVENT_TIME = 0x4,
376 /* see ctx_resched() for details */
377 EVENT_CPU = 0x8,
378 EVENT_CGROUP = 0x10,
379 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
380 };
381
382 /*
383 * perf_sched_events : >0 events exist
384 */
385
386 static void perf_sched_delayed(struct work_struct *work);
387 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
388 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
389 static DEFINE_MUTEX(perf_sched_mutex);
390 static atomic_t perf_sched_count;
391
392 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
393
394 static atomic_t nr_mmap_events __read_mostly;
395 static atomic_t nr_comm_events __read_mostly;
396 static atomic_t nr_namespaces_events __read_mostly;
397 static atomic_t nr_task_events __read_mostly;
398 static atomic_t nr_freq_events __read_mostly;
399 static atomic_t nr_switch_events __read_mostly;
400 static atomic_t nr_ksymbol_events __read_mostly;
401 static atomic_t nr_bpf_events __read_mostly;
402 static atomic_t nr_cgroup_events __read_mostly;
403 static atomic_t nr_text_poke_events __read_mostly;
404 static atomic_t nr_build_id_events __read_mostly;
405
406 static LIST_HEAD(pmus);
407 static DEFINE_MUTEX(pmus_lock);
408 static struct srcu_struct pmus_srcu;
409 static cpumask_var_t perf_online_mask;
410 static struct kmem_cache *perf_event_cache;
411
412 /*
413 * perf event paranoia level:
414 * -1 - not paranoid at all
415 * 0 - disallow raw tracepoint access for unpriv
416 * 1 - disallow cpu events for unpriv
417 * 2 - disallow kernel profiling for unpriv
418 */
419 int sysctl_perf_event_paranoid __read_mostly = 2;
420
421 /* Minimum for 512 kiB + 1 user control page */
422 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
423
424 /*
425 * max perf event sample rate
426 */
427 #define DEFAULT_MAX_SAMPLE_RATE 100000
428 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
429 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
430
431 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
432
433 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
434 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
435
436 static int perf_sample_allowed_ns __read_mostly =
437 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
438
update_perf_cpu_limits(void)439 static void update_perf_cpu_limits(void)
440 {
441 u64 tmp = perf_sample_period_ns;
442
443 tmp *= sysctl_perf_cpu_time_max_percent;
444 tmp = div_u64(tmp, 100);
445 if (!tmp)
446 tmp = 1;
447
448 WRITE_ONCE(perf_sample_allowed_ns, tmp);
449 }
450
451 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc);
452
perf_event_max_sample_rate_handler(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)453 int perf_event_max_sample_rate_handler(struct ctl_table *table, int write,
454 void *buffer, size_t *lenp, loff_t *ppos)
455 {
456 int ret;
457 int perf_cpu = sysctl_perf_cpu_time_max_percent;
458 /*
459 * If throttling is disabled don't allow the write:
460 */
461 if (write && (perf_cpu == 100 || perf_cpu == 0))
462 return -EINVAL;
463
464 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
465 if (ret || !write)
466 return ret;
467
468 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
469 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
470 update_perf_cpu_limits();
471
472 return 0;
473 }
474
475 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
476
perf_cpu_time_max_percent_handler(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)477 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
478 void *buffer, size_t *lenp, loff_t *ppos)
479 {
480 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
481
482 if (ret || !write)
483 return ret;
484
485 if (sysctl_perf_cpu_time_max_percent == 100 ||
486 sysctl_perf_cpu_time_max_percent == 0) {
487 printk(KERN_WARNING
488 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
489 WRITE_ONCE(perf_sample_allowed_ns, 0);
490 } else {
491 update_perf_cpu_limits();
492 }
493
494 return 0;
495 }
496
497 /*
498 * perf samples are done in some very critical code paths (NMIs).
499 * If they take too much CPU time, the system can lock up and not
500 * get any real work done. This will drop the sample rate when
501 * we detect that events are taking too long.
502 */
503 #define NR_ACCUMULATED_SAMPLES 128
504 static DEFINE_PER_CPU(u64, running_sample_length);
505
506 static u64 __report_avg;
507 static u64 __report_allowed;
508
perf_duration_warn(struct irq_work * w)509 static void perf_duration_warn(struct irq_work *w)
510 {
511 printk_ratelimited(KERN_INFO
512 "perf: interrupt took too long (%lld > %lld), lowering "
513 "kernel.perf_event_max_sample_rate to %d\n",
514 __report_avg, __report_allowed,
515 sysctl_perf_event_sample_rate);
516 }
517
518 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
519
perf_sample_event_took(u64 sample_len_ns)520 void perf_sample_event_took(u64 sample_len_ns)
521 {
522 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
523 u64 running_len;
524 u64 avg_len;
525 u32 max;
526
527 if (max_len == 0)
528 return;
529
530 /* Decay the counter by 1 average sample. */
531 running_len = __this_cpu_read(running_sample_length);
532 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
533 running_len += sample_len_ns;
534 __this_cpu_write(running_sample_length, running_len);
535
536 /*
537 * Note: this will be biased artifically low until we have
538 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
539 * from having to maintain a count.
540 */
541 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
542 if (avg_len <= max_len)
543 return;
544
545 __report_avg = avg_len;
546 __report_allowed = max_len;
547
548 /*
549 * Compute a throttle threshold 25% below the current duration.
550 */
551 avg_len += avg_len / 4;
552 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
553 if (avg_len < max)
554 max /= (u32)avg_len;
555 else
556 max = 1;
557
558 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
559 WRITE_ONCE(max_samples_per_tick, max);
560
561 sysctl_perf_event_sample_rate = max * HZ;
562 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
563
564 if (!irq_work_queue(&perf_duration_work)) {
565 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
566 "kernel.perf_event_max_sample_rate to %d\n",
567 __report_avg, __report_allowed,
568 sysctl_perf_event_sample_rate);
569 }
570 }
571
572 static atomic64_t perf_event_id;
573
574 static void update_context_time(struct perf_event_context *ctx);
575 static u64 perf_event_time(struct perf_event *event);
576
perf_event_print_debug(void)577 void __weak perf_event_print_debug(void) { }
578
perf_clock(void)579 static inline u64 perf_clock(void)
580 {
581 return local_clock();
582 }
583
perf_event_clock(struct perf_event * event)584 static inline u64 perf_event_clock(struct perf_event *event)
585 {
586 return event->clock();
587 }
588
589 /*
590 * State based event timekeeping...
591 *
592 * The basic idea is to use event->state to determine which (if any) time
593 * fields to increment with the current delta. This means we only need to
594 * update timestamps when we change state or when they are explicitly requested
595 * (read).
596 *
597 * Event groups make things a little more complicated, but not terribly so. The
598 * rules for a group are that if the group leader is OFF the entire group is
599 * OFF, irrespecive of what the group member states are. This results in
600 * __perf_effective_state().
601 *
602 * A futher ramification is that when a group leader flips between OFF and
603 * !OFF, we need to update all group member times.
604 *
605 *
606 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
607 * need to make sure the relevant context time is updated before we try and
608 * update our timestamps.
609 */
610
611 static __always_inline enum perf_event_state
__perf_effective_state(struct perf_event * event)612 __perf_effective_state(struct perf_event *event)
613 {
614 struct perf_event *leader = event->group_leader;
615
616 if (leader->state <= PERF_EVENT_STATE_OFF)
617 return leader->state;
618
619 return event->state;
620 }
621
622 static __always_inline void
__perf_update_times(struct perf_event * event,u64 now,u64 * enabled,u64 * running)623 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
624 {
625 enum perf_event_state state = __perf_effective_state(event);
626 u64 delta = now - event->tstamp;
627
628 *enabled = event->total_time_enabled;
629 if (state >= PERF_EVENT_STATE_INACTIVE)
630 *enabled += delta;
631
632 *running = event->total_time_running;
633 if (state >= PERF_EVENT_STATE_ACTIVE)
634 *running += delta;
635 }
636
perf_event_update_time(struct perf_event * event)637 static void perf_event_update_time(struct perf_event *event)
638 {
639 u64 now = perf_event_time(event);
640
641 __perf_update_times(event, now, &event->total_time_enabled,
642 &event->total_time_running);
643 event->tstamp = now;
644 }
645
perf_event_update_sibling_time(struct perf_event * leader)646 static void perf_event_update_sibling_time(struct perf_event *leader)
647 {
648 struct perf_event *sibling;
649
650 for_each_sibling_event(sibling, leader)
651 perf_event_update_time(sibling);
652 }
653
654 static void
perf_event_set_state(struct perf_event * event,enum perf_event_state state)655 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
656 {
657 if (event->state == state)
658 return;
659
660 perf_event_update_time(event);
661 /*
662 * If a group leader gets enabled/disabled all its siblings
663 * are affected too.
664 */
665 if ((event->state < 0) ^ (state < 0))
666 perf_event_update_sibling_time(event);
667
668 WRITE_ONCE(event->state, state);
669 }
670
671 /*
672 * UP store-release, load-acquire
673 */
674
675 #define __store_release(ptr, val) \
676 do { \
677 barrier(); \
678 WRITE_ONCE(*(ptr), (val)); \
679 } while (0)
680
681 #define __load_acquire(ptr) \
682 ({ \
683 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
684 barrier(); \
685 ___p; \
686 })
687
perf_ctx_disable(struct perf_event_context * ctx,bool cgroup)688 static void perf_ctx_disable(struct perf_event_context *ctx, bool cgroup)
689 {
690 struct perf_event_pmu_context *pmu_ctx;
691
692 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
693 if (cgroup && !pmu_ctx->nr_cgroups)
694 continue;
695 perf_pmu_disable(pmu_ctx->pmu);
696 }
697 }
698
perf_ctx_enable(struct perf_event_context * ctx,bool cgroup)699 static void perf_ctx_enable(struct perf_event_context *ctx, bool cgroup)
700 {
701 struct perf_event_pmu_context *pmu_ctx;
702
703 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
704 if (cgroup && !pmu_ctx->nr_cgroups)
705 continue;
706 perf_pmu_enable(pmu_ctx->pmu);
707 }
708 }
709
710 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type);
711 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type);
712
713 #ifdef CONFIG_CGROUP_PERF
714
715 static inline bool
perf_cgroup_match(struct perf_event * event)716 perf_cgroup_match(struct perf_event *event)
717 {
718 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
719
720 /* @event doesn't care about cgroup */
721 if (!event->cgrp)
722 return true;
723
724 /* wants specific cgroup scope but @cpuctx isn't associated with any */
725 if (!cpuctx->cgrp)
726 return false;
727
728 /*
729 * Cgroup scoping is recursive. An event enabled for a cgroup is
730 * also enabled for all its descendant cgroups. If @cpuctx's
731 * cgroup is a descendant of @event's (the test covers identity
732 * case), it's a match.
733 */
734 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
735 event->cgrp->css.cgroup);
736 }
737
perf_detach_cgroup(struct perf_event * event)738 static inline void perf_detach_cgroup(struct perf_event *event)
739 {
740 css_put(&event->cgrp->css);
741 event->cgrp = NULL;
742 }
743
is_cgroup_event(struct perf_event * event)744 static inline int is_cgroup_event(struct perf_event *event)
745 {
746 return event->cgrp != NULL;
747 }
748
perf_cgroup_event_time(struct perf_event * event)749 static inline u64 perf_cgroup_event_time(struct perf_event *event)
750 {
751 struct perf_cgroup_info *t;
752
753 t = per_cpu_ptr(event->cgrp->info, event->cpu);
754 return t->time;
755 }
756
perf_cgroup_event_time_now(struct perf_event * event,u64 now)757 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
758 {
759 struct perf_cgroup_info *t;
760
761 t = per_cpu_ptr(event->cgrp->info, event->cpu);
762 if (!__load_acquire(&t->active))
763 return t->time;
764 now += READ_ONCE(t->timeoffset);
765 return now;
766 }
767
__update_cgrp_time(struct perf_cgroup_info * info,u64 now,bool adv)768 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
769 {
770 if (adv)
771 info->time += now - info->timestamp;
772 info->timestamp = now;
773 /*
774 * see update_context_time()
775 */
776 WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
777 }
778
update_cgrp_time_from_cpuctx(struct perf_cpu_context * cpuctx,bool final)779 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
780 {
781 struct perf_cgroup *cgrp = cpuctx->cgrp;
782 struct cgroup_subsys_state *css;
783 struct perf_cgroup_info *info;
784
785 if (cgrp) {
786 u64 now = perf_clock();
787
788 for (css = &cgrp->css; css; css = css->parent) {
789 cgrp = container_of(css, struct perf_cgroup, css);
790 info = this_cpu_ptr(cgrp->info);
791
792 __update_cgrp_time(info, now, true);
793 if (final)
794 __store_release(&info->active, 0);
795 }
796 }
797 }
798
update_cgrp_time_from_event(struct perf_event * event)799 static inline void update_cgrp_time_from_event(struct perf_event *event)
800 {
801 struct perf_cgroup_info *info;
802
803 /*
804 * ensure we access cgroup data only when needed and
805 * when we know the cgroup is pinned (css_get)
806 */
807 if (!is_cgroup_event(event))
808 return;
809
810 info = this_cpu_ptr(event->cgrp->info);
811 /*
812 * Do not update time when cgroup is not active
813 */
814 if (info->active)
815 __update_cgrp_time(info, perf_clock(), true);
816 }
817
818 static inline void
perf_cgroup_set_timestamp(struct perf_cpu_context * cpuctx)819 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
820 {
821 struct perf_event_context *ctx = &cpuctx->ctx;
822 struct perf_cgroup *cgrp = cpuctx->cgrp;
823 struct perf_cgroup_info *info;
824 struct cgroup_subsys_state *css;
825
826 /*
827 * ctx->lock held by caller
828 * ensure we do not access cgroup data
829 * unless we have the cgroup pinned (css_get)
830 */
831 if (!cgrp)
832 return;
833
834 WARN_ON_ONCE(!ctx->nr_cgroups);
835
836 for (css = &cgrp->css; css; css = css->parent) {
837 cgrp = container_of(css, struct perf_cgroup, css);
838 info = this_cpu_ptr(cgrp->info);
839 __update_cgrp_time(info, ctx->timestamp, false);
840 __store_release(&info->active, 1);
841 }
842 }
843
844 /*
845 * reschedule events based on the cgroup constraint of task.
846 */
perf_cgroup_switch(struct task_struct * task)847 static void perf_cgroup_switch(struct task_struct *task)
848 {
849 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
850 struct perf_cgroup *cgrp;
851
852 /*
853 * cpuctx->cgrp is set when the first cgroup event enabled,
854 * and is cleared when the last cgroup event disabled.
855 */
856 if (READ_ONCE(cpuctx->cgrp) == NULL)
857 return;
858
859 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
860
861 cgrp = perf_cgroup_from_task(task, NULL);
862 if (READ_ONCE(cpuctx->cgrp) == cgrp)
863 return;
864
865 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
866 perf_ctx_disable(&cpuctx->ctx, true);
867
868 ctx_sched_out(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP);
869 /*
870 * must not be done before ctxswout due
871 * to update_cgrp_time_from_cpuctx() in
872 * ctx_sched_out()
873 */
874 cpuctx->cgrp = cgrp;
875 /*
876 * set cgrp before ctxsw in to allow
877 * perf_cgroup_set_timestamp() in ctx_sched_in()
878 * to not have to pass task around
879 */
880 ctx_sched_in(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP);
881
882 perf_ctx_enable(&cpuctx->ctx, true);
883 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
884 }
885
perf_cgroup_ensure_storage(struct perf_event * event,struct cgroup_subsys_state * css)886 static int perf_cgroup_ensure_storage(struct perf_event *event,
887 struct cgroup_subsys_state *css)
888 {
889 struct perf_cpu_context *cpuctx;
890 struct perf_event **storage;
891 int cpu, heap_size, ret = 0;
892
893 /*
894 * Allow storage to have sufficent space for an iterator for each
895 * possibly nested cgroup plus an iterator for events with no cgroup.
896 */
897 for (heap_size = 1; css; css = css->parent)
898 heap_size++;
899
900 for_each_possible_cpu(cpu) {
901 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
902 if (heap_size <= cpuctx->heap_size)
903 continue;
904
905 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
906 GFP_KERNEL, cpu_to_node(cpu));
907 if (!storage) {
908 ret = -ENOMEM;
909 break;
910 }
911
912 raw_spin_lock_irq(&cpuctx->ctx.lock);
913 if (cpuctx->heap_size < heap_size) {
914 swap(cpuctx->heap, storage);
915 if (storage == cpuctx->heap_default)
916 storage = NULL;
917 cpuctx->heap_size = heap_size;
918 }
919 raw_spin_unlock_irq(&cpuctx->ctx.lock);
920
921 kfree(storage);
922 }
923
924 return ret;
925 }
926
perf_cgroup_connect(int fd,struct perf_event * event,struct perf_event_attr * attr,struct perf_event * group_leader)927 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
928 struct perf_event_attr *attr,
929 struct perf_event *group_leader)
930 {
931 struct perf_cgroup *cgrp;
932 struct cgroup_subsys_state *css;
933 struct fd f = fdget(fd);
934 int ret = 0;
935
936 if (!f.file)
937 return -EBADF;
938
939 css = css_tryget_online_from_dir(f.file->f_path.dentry,
940 &perf_event_cgrp_subsys);
941 if (IS_ERR(css)) {
942 ret = PTR_ERR(css);
943 goto out;
944 }
945
946 ret = perf_cgroup_ensure_storage(event, css);
947 if (ret)
948 goto out;
949
950 cgrp = container_of(css, struct perf_cgroup, css);
951 event->cgrp = cgrp;
952
953 /*
954 * all events in a group must monitor
955 * the same cgroup because a task belongs
956 * to only one perf cgroup at a time
957 */
958 if (group_leader && group_leader->cgrp != cgrp) {
959 perf_detach_cgroup(event);
960 ret = -EINVAL;
961 }
962 out:
963 fdput(f);
964 return ret;
965 }
966
967 static inline void
perf_cgroup_event_enable(struct perf_event * event,struct perf_event_context * ctx)968 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
969 {
970 struct perf_cpu_context *cpuctx;
971
972 if (!is_cgroup_event(event))
973 return;
974
975 event->pmu_ctx->nr_cgroups++;
976
977 /*
978 * Because cgroup events are always per-cpu events,
979 * @ctx == &cpuctx->ctx.
980 */
981 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
982
983 if (ctx->nr_cgroups++)
984 return;
985
986 cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
987 }
988
989 static inline void
perf_cgroup_event_disable(struct perf_event * event,struct perf_event_context * ctx)990 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
991 {
992 struct perf_cpu_context *cpuctx;
993
994 if (!is_cgroup_event(event))
995 return;
996
997 event->pmu_ctx->nr_cgroups--;
998
999 /*
1000 * Because cgroup events are always per-cpu events,
1001 * @ctx == &cpuctx->ctx.
1002 */
1003 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1004
1005 if (--ctx->nr_cgroups)
1006 return;
1007
1008 cpuctx->cgrp = NULL;
1009 }
1010
1011 #else /* !CONFIG_CGROUP_PERF */
1012
1013 static inline bool
perf_cgroup_match(struct perf_event * event)1014 perf_cgroup_match(struct perf_event *event)
1015 {
1016 return true;
1017 }
1018
perf_detach_cgroup(struct perf_event * event)1019 static inline void perf_detach_cgroup(struct perf_event *event)
1020 {}
1021
is_cgroup_event(struct perf_event * event)1022 static inline int is_cgroup_event(struct perf_event *event)
1023 {
1024 return 0;
1025 }
1026
update_cgrp_time_from_event(struct perf_event * event)1027 static inline void update_cgrp_time_from_event(struct perf_event *event)
1028 {
1029 }
1030
update_cgrp_time_from_cpuctx(struct perf_cpu_context * cpuctx,bool final)1031 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1032 bool final)
1033 {
1034 }
1035
perf_cgroup_connect(pid_t pid,struct perf_event * event,struct perf_event_attr * attr,struct perf_event * group_leader)1036 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1037 struct perf_event_attr *attr,
1038 struct perf_event *group_leader)
1039 {
1040 return -EINVAL;
1041 }
1042
1043 static inline void
perf_cgroup_set_timestamp(struct perf_cpu_context * cpuctx)1044 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1045 {
1046 }
1047
perf_cgroup_event_time(struct perf_event * event)1048 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1049 {
1050 return 0;
1051 }
1052
perf_cgroup_event_time_now(struct perf_event * event,u64 now)1053 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1054 {
1055 return 0;
1056 }
1057
1058 static inline void
perf_cgroup_event_enable(struct perf_event * event,struct perf_event_context * ctx)1059 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1060 {
1061 }
1062
1063 static inline void
perf_cgroup_event_disable(struct perf_event * event,struct perf_event_context * ctx)1064 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1065 {
1066 }
1067
perf_cgroup_switch(struct task_struct * task)1068 static void perf_cgroup_switch(struct task_struct *task)
1069 {
1070 }
1071 #endif
1072
1073 /*
1074 * set default to be dependent on timer tick just
1075 * like original code
1076 */
1077 #define PERF_CPU_HRTIMER (1000 / HZ)
1078 /*
1079 * function must be called with interrupts disabled
1080 */
perf_mux_hrtimer_handler(struct hrtimer * hr)1081 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1082 {
1083 struct perf_cpu_pmu_context *cpc;
1084 bool rotations;
1085
1086 lockdep_assert_irqs_disabled();
1087
1088 cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer);
1089 rotations = perf_rotate_context(cpc);
1090
1091 raw_spin_lock(&cpc->hrtimer_lock);
1092 if (rotations)
1093 hrtimer_forward_now(hr, cpc->hrtimer_interval);
1094 else
1095 cpc->hrtimer_active = 0;
1096 raw_spin_unlock(&cpc->hrtimer_lock);
1097
1098 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1099 }
1100
__perf_mux_hrtimer_init(struct perf_cpu_pmu_context * cpc,int cpu)1101 static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu)
1102 {
1103 struct hrtimer *timer = &cpc->hrtimer;
1104 struct pmu *pmu = cpc->epc.pmu;
1105 u64 interval;
1106
1107 /*
1108 * check default is sane, if not set then force to
1109 * default interval (1/tick)
1110 */
1111 interval = pmu->hrtimer_interval_ms;
1112 if (interval < 1)
1113 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1114
1115 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1116
1117 raw_spin_lock_init(&cpc->hrtimer_lock);
1118 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1119 timer->function = perf_mux_hrtimer_handler;
1120 }
1121
perf_mux_hrtimer_restart(struct perf_cpu_pmu_context * cpc)1122 static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc)
1123 {
1124 struct hrtimer *timer = &cpc->hrtimer;
1125 unsigned long flags;
1126
1127 raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags);
1128 if (!cpc->hrtimer_active) {
1129 cpc->hrtimer_active = 1;
1130 hrtimer_forward_now(timer, cpc->hrtimer_interval);
1131 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1132 }
1133 raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags);
1134
1135 return 0;
1136 }
1137
perf_mux_hrtimer_restart_ipi(void * arg)1138 static int perf_mux_hrtimer_restart_ipi(void *arg)
1139 {
1140 return perf_mux_hrtimer_restart(arg);
1141 }
1142
perf_pmu_disable(struct pmu * pmu)1143 void perf_pmu_disable(struct pmu *pmu)
1144 {
1145 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1146 if (!(*count)++)
1147 pmu->pmu_disable(pmu);
1148 }
1149
perf_pmu_enable(struct pmu * pmu)1150 void perf_pmu_enable(struct pmu *pmu)
1151 {
1152 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1153 if (!--(*count))
1154 pmu->pmu_enable(pmu);
1155 }
1156
perf_assert_pmu_disabled(struct pmu * pmu)1157 static void perf_assert_pmu_disabled(struct pmu *pmu)
1158 {
1159 WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
1160 }
1161
get_ctx(struct perf_event_context * ctx)1162 static void get_ctx(struct perf_event_context *ctx)
1163 {
1164 refcount_inc(&ctx->refcount);
1165 }
1166
alloc_task_ctx_data(struct pmu * pmu)1167 static void *alloc_task_ctx_data(struct pmu *pmu)
1168 {
1169 if (pmu->task_ctx_cache)
1170 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1171
1172 return NULL;
1173 }
1174
free_task_ctx_data(struct pmu * pmu,void * task_ctx_data)1175 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1176 {
1177 if (pmu->task_ctx_cache && task_ctx_data)
1178 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1179 }
1180
free_ctx(struct rcu_head * head)1181 static void free_ctx(struct rcu_head *head)
1182 {
1183 struct perf_event_context *ctx;
1184
1185 ctx = container_of(head, struct perf_event_context, rcu_head);
1186 kfree(ctx);
1187 }
1188
put_ctx(struct perf_event_context * ctx)1189 static void put_ctx(struct perf_event_context *ctx)
1190 {
1191 if (refcount_dec_and_test(&ctx->refcount)) {
1192 if (ctx->parent_ctx)
1193 put_ctx(ctx->parent_ctx);
1194 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1195 put_task_struct(ctx->task);
1196 call_rcu(&ctx->rcu_head, free_ctx);
1197 }
1198 }
1199
1200 /*
1201 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1202 * perf_pmu_migrate_context() we need some magic.
1203 *
1204 * Those places that change perf_event::ctx will hold both
1205 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1206 *
1207 * Lock ordering is by mutex address. There are two other sites where
1208 * perf_event_context::mutex nests and those are:
1209 *
1210 * - perf_event_exit_task_context() [ child , 0 ]
1211 * perf_event_exit_event()
1212 * put_event() [ parent, 1 ]
1213 *
1214 * - perf_event_init_context() [ parent, 0 ]
1215 * inherit_task_group()
1216 * inherit_group()
1217 * inherit_event()
1218 * perf_event_alloc()
1219 * perf_init_event()
1220 * perf_try_init_event() [ child , 1 ]
1221 *
1222 * While it appears there is an obvious deadlock here -- the parent and child
1223 * nesting levels are inverted between the two. This is in fact safe because
1224 * life-time rules separate them. That is an exiting task cannot fork, and a
1225 * spawning task cannot (yet) exit.
1226 *
1227 * But remember that these are parent<->child context relations, and
1228 * migration does not affect children, therefore these two orderings should not
1229 * interact.
1230 *
1231 * The change in perf_event::ctx does not affect children (as claimed above)
1232 * because the sys_perf_event_open() case will install a new event and break
1233 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1234 * concerned with cpuctx and that doesn't have children.
1235 *
1236 * The places that change perf_event::ctx will issue:
1237 *
1238 * perf_remove_from_context();
1239 * synchronize_rcu();
1240 * perf_install_in_context();
1241 *
1242 * to affect the change. The remove_from_context() + synchronize_rcu() should
1243 * quiesce the event, after which we can install it in the new location. This
1244 * means that only external vectors (perf_fops, prctl) can perturb the event
1245 * while in transit. Therefore all such accessors should also acquire
1246 * perf_event_context::mutex to serialize against this.
1247 *
1248 * However; because event->ctx can change while we're waiting to acquire
1249 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1250 * function.
1251 *
1252 * Lock order:
1253 * exec_update_lock
1254 * task_struct::perf_event_mutex
1255 * perf_event_context::mutex
1256 * perf_event::child_mutex;
1257 * perf_event_context::lock
1258 * perf_event::mmap_mutex
1259 * mmap_lock
1260 * perf_addr_filters_head::lock
1261 *
1262 * cpu_hotplug_lock
1263 * pmus_lock
1264 * cpuctx->mutex / perf_event_context::mutex
1265 */
1266 static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event * event,int nesting)1267 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1268 {
1269 struct perf_event_context *ctx;
1270
1271 again:
1272 rcu_read_lock();
1273 ctx = READ_ONCE(event->ctx);
1274 if (!refcount_inc_not_zero(&ctx->refcount)) {
1275 rcu_read_unlock();
1276 goto again;
1277 }
1278 rcu_read_unlock();
1279
1280 mutex_lock_nested(&ctx->mutex, nesting);
1281 if (event->ctx != ctx) {
1282 mutex_unlock(&ctx->mutex);
1283 put_ctx(ctx);
1284 goto again;
1285 }
1286
1287 return ctx;
1288 }
1289
1290 static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event * event)1291 perf_event_ctx_lock(struct perf_event *event)
1292 {
1293 return perf_event_ctx_lock_nested(event, 0);
1294 }
1295
perf_event_ctx_unlock(struct perf_event * event,struct perf_event_context * ctx)1296 static void perf_event_ctx_unlock(struct perf_event *event,
1297 struct perf_event_context *ctx)
1298 {
1299 mutex_unlock(&ctx->mutex);
1300 put_ctx(ctx);
1301 }
1302
1303 /*
1304 * This must be done under the ctx->lock, such as to serialize against
1305 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1306 * calling scheduler related locks and ctx->lock nests inside those.
1307 */
1308 static __must_check struct perf_event_context *
unclone_ctx(struct perf_event_context * ctx)1309 unclone_ctx(struct perf_event_context *ctx)
1310 {
1311 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1312
1313 lockdep_assert_held(&ctx->lock);
1314
1315 if (parent_ctx)
1316 ctx->parent_ctx = NULL;
1317 ctx->generation++;
1318
1319 return parent_ctx;
1320 }
1321
perf_event_pid_type(struct perf_event * event,struct task_struct * p,enum pid_type type)1322 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1323 enum pid_type type)
1324 {
1325 u32 nr;
1326 /*
1327 * only top level events have the pid namespace they were created in
1328 */
1329 if (event->parent)
1330 event = event->parent;
1331
1332 nr = __task_pid_nr_ns(p, type, event->ns);
1333 /* avoid -1 if it is idle thread or runs in another ns */
1334 if (!nr && !pid_alive(p))
1335 nr = -1;
1336 return nr;
1337 }
1338
perf_event_pid(struct perf_event * event,struct task_struct * p)1339 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1340 {
1341 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1342 }
1343
perf_event_tid(struct perf_event * event,struct task_struct * p)1344 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1345 {
1346 return perf_event_pid_type(event, p, PIDTYPE_PID);
1347 }
1348
1349 /*
1350 * If we inherit events we want to return the parent event id
1351 * to userspace.
1352 */
primary_event_id(struct perf_event * event)1353 static u64 primary_event_id(struct perf_event *event)
1354 {
1355 u64 id = event->id;
1356
1357 if (event->parent)
1358 id = event->parent->id;
1359
1360 return id;
1361 }
1362
1363 /*
1364 * Get the perf_event_context for a task and lock it.
1365 *
1366 * This has to cope with the fact that until it is locked,
1367 * the context could get moved to another task.
1368 */
1369 static struct perf_event_context *
perf_lock_task_context(struct task_struct * task,unsigned long * flags)1370 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
1371 {
1372 struct perf_event_context *ctx;
1373
1374 retry:
1375 /*
1376 * One of the few rules of preemptible RCU is that one cannot do
1377 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1378 * part of the read side critical section was irqs-enabled -- see
1379 * rcu_read_unlock_special().
1380 *
1381 * Since ctx->lock nests under rq->lock we must ensure the entire read
1382 * side critical section has interrupts disabled.
1383 */
1384 local_irq_save(*flags);
1385 rcu_read_lock();
1386 ctx = rcu_dereference(task->perf_event_ctxp);
1387 if (ctx) {
1388 /*
1389 * If this context is a clone of another, it might
1390 * get swapped for another underneath us by
1391 * perf_event_task_sched_out, though the
1392 * rcu_read_lock() protects us from any context
1393 * getting freed. Lock the context and check if it
1394 * got swapped before we could get the lock, and retry
1395 * if so. If we locked the right context, then it
1396 * can't get swapped on us any more.
1397 */
1398 raw_spin_lock(&ctx->lock);
1399 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
1400 raw_spin_unlock(&ctx->lock);
1401 rcu_read_unlock();
1402 local_irq_restore(*flags);
1403 goto retry;
1404 }
1405
1406 if (ctx->task == TASK_TOMBSTONE ||
1407 !refcount_inc_not_zero(&ctx->refcount)) {
1408 raw_spin_unlock(&ctx->lock);
1409 ctx = NULL;
1410 } else {
1411 WARN_ON_ONCE(ctx->task != task);
1412 }
1413 }
1414 rcu_read_unlock();
1415 if (!ctx)
1416 local_irq_restore(*flags);
1417 return ctx;
1418 }
1419
1420 /*
1421 * Get the context for a task and increment its pin_count so it
1422 * can't get swapped to another task. This also increments its
1423 * reference count so that the context can't get freed.
1424 */
1425 static struct perf_event_context *
perf_pin_task_context(struct task_struct * task)1426 perf_pin_task_context(struct task_struct *task)
1427 {
1428 struct perf_event_context *ctx;
1429 unsigned long flags;
1430
1431 ctx = perf_lock_task_context(task, &flags);
1432 if (ctx) {
1433 ++ctx->pin_count;
1434 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1435 }
1436 return ctx;
1437 }
1438
perf_unpin_context(struct perf_event_context * ctx)1439 static void perf_unpin_context(struct perf_event_context *ctx)
1440 {
1441 unsigned long flags;
1442
1443 raw_spin_lock_irqsave(&ctx->lock, flags);
1444 --ctx->pin_count;
1445 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1446 }
1447
1448 /*
1449 * Update the record of the current time in a context.
1450 */
__update_context_time(struct perf_event_context * ctx,bool adv)1451 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1452 {
1453 u64 now = perf_clock();
1454
1455 lockdep_assert_held(&ctx->lock);
1456
1457 if (adv)
1458 ctx->time += now - ctx->timestamp;
1459 ctx->timestamp = now;
1460
1461 /*
1462 * The above: time' = time + (now - timestamp), can be re-arranged
1463 * into: time` = now + (time - timestamp), which gives a single value
1464 * offset to compute future time without locks on.
1465 *
1466 * See perf_event_time_now(), which can be used from NMI context where
1467 * it's (obviously) not possible to acquire ctx->lock in order to read
1468 * both the above values in a consistent manner.
1469 */
1470 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1471 }
1472
update_context_time(struct perf_event_context * ctx)1473 static void update_context_time(struct perf_event_context *ctx)
1474 {
1475 __update_context_time(ctx, true);
1476 }
1477
perf_event_time(struct perf_event * event)1478 static u64 perf_event_time(struct perf_event *event)
1479 {
1480 struct perf_event_context *ctx = event->ctx;
1481
1482 if (unlikely(!ctx))
1483 return 0;
1484
1485 if (is_cgroup_event(event))
1486 return perf_cgroup_event_time(event);
1487
1488 return ctx->time;
1489 }
1490
perf_event_time_now(struct perf_event * event,u64 now)1491 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1492 {
1493 struct perf_event_context *ctx = event->ctx;
1494
1495 if (unlikely(!ctx))
1496 return 0;
1497
1498 if (is_cgroup_event(event))
1499 return perf_cgroup_event_time_now(event, now);
1500
1501 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1502 return ctx->time;
1503
1504 now += READ_ONCE(ctx->timeoffset);
1505 return now;
1506 }
1507
get_event_type(struct perf_event * event)1508 static enum event_type_t get_event_type(struct perf_event *event)
1509 {
1510 struct perf_event_context *ctx = event->ctx;
1511 enum event_type_t event_type;
1512
1513 lockdep_assert_held(&ctx->lock);
1514
1515 /*
1516 * It's 'group type', really, because if our group leader is
1517 * pinned, so are we.
1518 */
1519 if (event->group_leader != event)
1520 event = event->group_leader;
1521
1522 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1523 if (!ctx->task)
1524 event_type |= EVENT_CPU;
1525
1526 return event_type;
1527 }
1528
1529 /*
1530 * Helper function to initialize event group nodes.
1531 */
init_event_group(struct perf_event * event)1532 static void init_event_group(struct perf_event *event)
1533 {
1534 RB_CLEAR_NODE(&event->group_node);
1535 event->group_index = 0;
1536 }
1537
1538 /*
1539 * Extract pinned or flexible groups from the context
1540 * based on event attrs bits.
1541 */
1542 static struct perf_event_groups *
get_event_groups(struct perf_event * event,struct perf_event_context * ctx)1543 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1544 {
1545 if (event->attr.pinned)
1546 return &ctx->pinned_groups;
1547 else
1548 return &ctx->flexible_groups;
1549 }
1550
1551 /*
1552 * Helper function to initializes perf_event_group trees.
1553 */
perf_event_groups_init(struct perf_event_groups * groups)1554 static void perf_event_groups_init(struct perf_event_groups *groups)
1555 {
1556 groups->tree = RB_ROOT;
1557 groups->index = 0;
1558 }
1559
event_cgroup(const struct perf_event * event)1560 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1561 {
1562 struct cgroup *cgroup = NULL;
1563
1564 #ifdef CONFIG_CGROUP_PERF
1565 if (event->cgrp)
1566 cgroup = event->cgrp->css.cgroup;
1567 #endif
1568
1569 return cgroup;
1570 }
1571
1572 /*
1573 * Compare function for event groups;
1574 *
1575 * Implements complex key that first sorts by CPU and then by virtual index
1576 * which provides ordering when rotating groups for the same CPU.
1577 */
1578 static __always_inline int
perf_event_groups_cmp(const int left_cpu,const struct pmu * left_pmu,const struct cgroup * left_cgroup,const u64 left_group_index,const struct perf_event * right)1579 perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu,
1580 const struct cgroup *left_cgroup, const u64 left_group_index,
1581 const struct perf_event *right)
1582 {
1583 if (left_cpu < right->cpu)
1584 return -1;
1585 if (left_cpu > right->cpu)
1586 return 1;
1587
1588 if (left_pmu) {
1589 if (left_pmu < right->pmu_ctx->pmu)
1590 return -1;
1591 if (left_pmu > right->pmu_ctx->pmu)
1592 return 1;
1593 }
1594
1595 #ifdef CONFIG_CGROUP_PERF
1596 {
1597 const struct cgroup *right_cgroup = event_cgroup(right);
1598
1599 if (left_cgroup != right_cgroup) {
1600 if (!left_cgroup) {
1601 /*
1602 * Left has no cgroup but right does, no
1603 * cgroups come first.
1604 */
1605 return -1;
1606 }
1607 if (!right_cgroup) {
1608 /*
1609 * Right has no cgroup but left does, no
1610 * cgroups come first.
1611 */
1612 return 1;
1613 }
1614 /* Two dissimilar cgroups, order by id. */
1615 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1616 return -1;
1617
1618 return 1;
1619 }
1620 }
1621 #endif
1622
1623 if (left_group_index < right->group_index)
1624 return -1;
1625 if (left_group_index > right->group_index)
1626 return 1;
1627
1628 return 0;
1629 }
1630
1631 #define __node_2_pe(node) \
1632 rb_entry((node), struct perf_event, group_node)
1633
__group_less(struct rb_node * a,const struct rb_node * b)1634 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1635 {
1636 struct perf_event *e = __node_2_pe(a);
1637 return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e),
1638 e->group_index, __node_2_pe(b)) < 0;
1639 }
1640
1641 struct __group_key {
1642 int cpu;
1643 struct pmu *pmu;
1644 struct cgroup *cgroup;
1645 };
1646
__group_cmp(const void * key,const struct rb_node * node)1647 static inline int __group_cmp(const void *key, const struct rb_node *node)
1648 {
1649 const struct __group_key *a = key;
1650 const struct perf_event *b = __node_2_pe(node);
1651
1652 /* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */
1653 return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b);
1654 }
1655
1656 static inline int
__group_cmp_ignore_cgroup(const void * key,const struct rb_node * node)1657 __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node)
1658 {
1659 const struct __group_key *a = key;
1660 const struct perf_event *b = __node_2_pe(node);
1661
1662 /* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */
1663 return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b),
1664 b->group_index, b);
1665 }
1666
1667 /*
1668 * Insert @event into @groups' tree; using
1669 * {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index}
1670 * as key. This places it last inside the {cpu,pmu,cgroup} subtree.
1671 */
1672 static void
perf_event_groups_insert(struct perf_event_groups * groups,struct perf_event * event)1673 perf_event_groups_insert(struct perf_event_groups *groups,
1674 struct perf_event *event)
1675 {
1676 event->group_index = ++groups->index;
1677
1678 rb_add(&event->group_node, &groups->tree, __group_less);
1679 }
1680
1681 /*
1682 * Helper function to insert event into the pinned or flexible groups.
1683 */
1684 static void
add_event_to_groups(struct perf_event * event,struct perf_event_context * ctx)1685 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1686 {
1687 struct perf_event_groups *groups;
1688
1689 groups = get_event_groups(event, ctx);
1690 perf_event_groups_insert(groups, event);
1691 }
1692
1693 /*
1694 * Delete a group from a tree.
1695 */
1696 static void
perf_event_groups_delete(struct perf_event_groups * groups,struct perf_event * event)1697 perf_event_groups_delete(struct perf_event_groups *groups,
1698 struct perf_event *event)
1699 {
1700 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1701 RB_EMPTY_ROOT(&groups->tree));
1702
1703 rb_erase(&event->group_node, &groups->tree);
1704 init_event_group(event);
1705 }
1706
1707 /*
1708 * Helper function to delete event from its groups.
1709 */
1710 static void
del_event_from_groups(struct perf_event * event,struct perf_event_context * ctx)1711 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1712 {
1713 struct perf_event_groups *groups;
1714
1715 groups = get_event_groups(event, ctx);
1716 perf_event_groups_delete(groups, event);
1717 }
1718
1719 /*
1720 * Get the leftmost event in the {cpu,pmu,cgroup} subtree.
1721 */
1722 static struct perf_event *
perf_event_groups_first(struct perf_event_groups * groups,int cpu,struct pmu * pmu,struct cgroup * cgrp)1723 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1724 struct pmu *pmu, struct cgroup *cgrp)
1725 {
1726 struct __group_key key = {
1727 .cpu = cpu,
1728 .pmu = pmu,
1729 .cgroup = cgrp,
1730 };
1731 struct rb_node *node;
1732
1733 node = rb_find_first(&key, &groups->tree, __group_cmp);
1734 if (node)
1735 return __node_2_pe(node);
1736
1737 return NULL;
1738 }
1739
1740 static struct perf_event *
perf_event_groups_next(struct perf_event * event,struct pmu * pmu)1741 perf_event_groups_next(struct perf_event *event, struct pmu *pmu)
1742 {
1743 struct __group_key key = {
1744 .cpu = event->cpu,
1745 .pmu = pmu,
1746 .cgroup = event_cgroup(event),
1747 };
1748 struct rb_node *next;
1749
1750 next = rb_next_match(&key, &event->group_node, __group_cmp);
1751 if (next)
1752 return __node_2_pe(next);
1753
1754 return NULL;
1755 }
1756
1757 #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) \
1758 for (event = perf_event_groups_first(groups, cpu, pmu, NULL); \
1759 event; event = perf_event_groups_next(event, pmu))
1760
1761 /*
1762 * Iterate through the whole groups tree.
1763 */
1764 #define perf_event_groups_for_each(event, groups) \
1765 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1766 typeof(*event), group_node); event; \
1767 event = rb_entry_safe(rb_next(&event->group_node), \
1768 typeof(*event), group_node))
1769
1770 /*
1771 * Add an event from the lists for its context.
1772 * Must be called with ctx->mutex and ctx->lock held.
1773 */
1774 static void
list_add_event(struct perf_event * event,struct perf_event_context * ctx)1775 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1776 {
1777 lockdep_assert_held(&ctx->lock);
1778
1779 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1780 event->attach_state |= PERF_ATTACH_CONTEXT;
1781
1782 event->tstamp = perf_event_time(event);
1783
1784 /*
1785 * If we're a stand alone event or group leader, we go to the context
1786 * list, group events are kept attached to the group so that
1787 * perf_group_detach can, at all times, locate all siblings.
1788 */
1789 if (event->group_leader == event) {
1790 event->group_caps = event->event_caps;
1791 add_event_to_groups(event, ctx);
1792 }
1793
1794 list_add_rcu(&event->event_entry, &ctx->event_list);
1795 ctx->nr_events++;
1796 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1797 ctx->nr_user++;
1798 if (event->attr.inherit_stat)
1799 ctx->nr_stat++;
1800
1801 if (event->state > PERF_EVENT_STATE_OFF)
1802 perf_cgroup_event_enable(event, ctx);
1803
1804 ctx->generation++;
1805 event->pmu_ctx->nr_events++;
1806 }
1807
1808 /*
1809 * Initialize event state based on the perf_event_attr::disabled.
1810 */
perf_event__state_init(struct perf_event * event)1811 static inline void perf_event__state_init(struct perf_event *event)
1812 {
1813 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1814 PERF_EVENT_STATE_INACTIVE;
1815 }
1816
__perf_event_read_size(u64 read_format,int nr_siblings)1817 static int __perf_event_read_size(u64 read_format, int nr_siblings)
1818 {
1819 int entry = sizeof(u64); /* value */
1820 int size = 0;
1821 int nr = 1;
1822
1823 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1824 size += sizeof(u64);
1825
1826 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1827 size += sizeof(u64);
1828
1829 if (read_format & PERF_FORMAT_ID)
1830 entry += sizeof(u64);
1831
1832 if (read_format & PERF_FORMAT_LOST)
1833 entry += sizeof(u64);
1834
1835 if (read_format & PERF_FORMAT_GROUP) {
1836 nr += nr_siblings;
1837 size += sizeof(u64);
1838 }
1839
1840 /*
1841 * Since perf_event_validate_size() limits this to 16k and inhibits
1842 * adding more siblings, this will never overflow.
1843 */
1844 return size + nr * entry;
1845 }
1846
__perf_event_header_size(struct perf_event * event,u64 sample_type)1847 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1848 {
1849 struct perf_sample_data *data;
1850 u16 size = 0;
1851
1852 if (sample_type & PERF_SAMPLE_IP)
1853 size += sizeof(data->ip);
1854
1855 if (sample_type & PERF_SAMPLE_ADDR)
1856 size += sizeof(data->addr);
1857
1858 if (sample_type & PERF_SAMPLE_PERIOD)
1859 size += sizeof(data->period);
1860
1861 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1862 size += sizeof(data->weight.full);
1863
1864 if (sample_type & PERF_SAMPLE_READ)
1865 size += event->read_size;
1866
1867 if (sample_type & PERF_SAMPLE_DATA_SRC)
1868 size += sizeof(data->data_src.val);
1869
1870 if (sample_type & PERF_SAMPLE_TRANSACTION)
1871 size += sizeof(data->txn);
1872
1873 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1874 size += sizeof(data->phys_addr);
1875
1876 if (sample_type & PERF_SAMPLE_CGROUP)
1877 size += sizeof(data->cgroup);
1878
1879 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1880 size += sizeof(data->data_page_size);
1881
1882 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1883 size += sizeof(data->code_page_size);
1884
1885 event->header_size = size;
1886 }
1887
1888 /*
1889 * Called at perf_event creation and when events are attached/detached from a
1890 * group.
1891 */
perf_event__header_size(struct perf_event * event)1892 static void perf_event__header_size(struct perf_event *event)
1893 {
1894 event->read_size =
1895 __perf_event_read_size(event->attr.read_format,
1896 event->group_leader->nr_siblings);
1897 __perf_event_header_size(event, event->attr.sample_type);
1898 }
1899
perf_event__id_header_size(struct perf_event * event)1900 static void perf_event__id_header_size(struct perf_event *event)
1901 {
1902 struct perf_sample_data *data;
1903 u64 sample_type = event->attr.sample_type;
1904 u16 size = 0;
1905
1906 if (sample_type & PERF_SAMPLE_TID)
1907 size += sizeof(data->tid_entry);
1908
1909 if (sample_type & PERF_SAMPLE_TIME)
1910 size += sizeof(data->time);
1911
1912 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1913 size += sizeof(data->id);
1914
1915 if (sample_type & PERF_SAMPLE_ID)
1916 size += sizeof(data->id);
1917
1918 if (sample_type & PERF_SAMPLE_STREAM_ID)
1919 size += sizeof(data->stream_id);
1920
1921 if (sample_type & PERF_SAMPLE_CPU)
1922 size += sizeof(data->cpu_entry);
1923
1924 event->id_header_size = size;
1925 }
1926
1927 /*
1928 * Check that adding an event to the group does not result in anybody
1929 * overflowing the 64k event limit imposed by the output buffer.
1930 *
1931 * Specifically, check that the read_size for the event does not exceed 16k,
1932 * read_size being the one term that grows with groups size. Since read_size
1933 * depends on per-event read_format, also (re)check the existing events.
1934 *
1935 * This leaves 48k for the constant size fields and things like callchains,
1936 * branch stacks and register sets.
1937 */
perf_event_validate_size(struct perf_event * event)1938 static bool perf_event_validate_size(struct perf_event *event)
1939 {
1940 struct perf_event *sibling, *group_leader = event->group_leader;
1941
1942 if (__perf_event_read_size(event->attr.read_format,
1943 group_leader->nr_siblings + 1) > 16*1024)
1944 return false;
1945
1946 if (__perf_event_read_size(group_leader->attr.read_format,
1947 group_leader->nr_siblings + 1) > 16*1024)
1948 return false;
1949
1950 /*
1951 * When creating a new group leader, group_leader->ctx is initialized
1952 * after the size has been validated, but we cannot safely use
1953 * for_each_sibling_event() until group_leader->ctx is set. A new group
1954 * leader cannot have any siblings yet, so we can safely skip checking
1955 * the non-existent siblings.
1956 */
1957 if (event == group_leader)
1958 return true;
1959
1960 for_each_sibling_event(sibling, group_leader) {
1961 if (__perf_event_read_size(sibling->attr.read_format,
1962 group_leader->nr_siblings + 1) > 16*1024)
1963 return false;
1964 }
1965
1966 return true;
1967 }
1968
perf_group_attach(struct perf_event * event)1969 static void perf_group_attach(struct perf_event *event)
1970 {
1971 struct perf_event *group_leader = event->group_leader, *pos;
1972
1973 lockdep_assert_held(&event->ctx->lock);
1974
1975 /*
1976 * We can have double attach due to group movement (move_group) in
1977 * perf_event_open().
1978 */
1979 if (event->attach_state & PERF_ATTACH_GROUP)
1980 return;
1981
1982 event->attach_state |= PERF_ATTACH_GROUP;
1983
1984 if (group_leader == event)
1985 return;
1986
1987 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1988
1989 group_leader->group_caps &= event->event_caps;
1990
1991 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1992 group_leader->nr_siblings++;
1993 group_leader->group_generation++;
1994
1995 perf_event__header_size(group_leader);
1996
1997 for_each_sibling_event(pos, group_leader)
1998 perf_event__header_size(pos);
1999 }
2000
2001 /*
2002 * Remove an event from the lists for its context.
2003 * Must be called with ctx->mutex and ctx->lock held.
2004 */
2005 static void
list_del_event(struct perf_event * event,struct perf_event_context * ctx)2006 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
2007 {
2008 WARN_ON_ONCE(event->ctx != ctx);
2009 lockdep_assert_held(&ctx->lock);
2010
2011 /*
2012 * We can have double detach due to exit/hot-unplug + close.
2013 */
2014 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
2015 return;
2016
2017 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2018
2019 ctx->nr_events--;
2020 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
2021 ctx->nr_user--;
2022 if (event->attr.inherit_stat)
2023 ctx->nr_stat--;
2024
2025 list_del_rcu(&event->event_entry);
2026
2027 if (event->group_leader == event)
2028 del_event_from_groups(event, ctx);
2029
2030 /*
2031 * If event was in error state, then keep it
2032 * that way, otherwise bogus counts will be
2033 * returned on read(). The only way to get out
2034 * of error state is by explicit re-enabling
2035 * of the event
2036 */
2037 if (event->state > PERF_EVENT_STATE_OFF) {
2038 perf_cgroup_event_disable(event, ctx);
2039 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2040 }
2041
2042 ctx->generation++;
2043 event->pmu_ctx->nr_events--;
2044 }
2045
2046 static int
perf_aux_output_match(struct perf_event * event,struct perf_event * aux_event)2047 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2048 {
2049 if (!has_aux(aux_event))
2050 return 0;
2051
2052 if (!event->pmu->aux_output_match)
2053 return 0;
2054
2055 return event->pmu->aux_output_match(aux_event);
2056 }
2057
2058 static void put_event(struct perf_event *event);
2059 static void event_sched_out(struct perf_event *event,
2060 struct perf_event_context *ctx);
2061
perf_put_aux_event(struct perf_event * event)2062 static void perf_put_aux_event(struct perf_event *event)
2063 {
2064 struct perf_event_context *ctx = event->ctx;
2065 struct perf_event *iter;
2066
2067 /*
2068 * If event uses aux_event tear down the link
2069 */
2070 if (event->aux_event) {
2071 iter = event->aux_event;
2072 event->aux_event = NULL;
2073 put_event(iter);
2074 return;
2075 }
2076
2077 /*
2078 * If the event is an aux_event, tear down all links to
2079 * it from other events.
2080 */
2081 for_each_sibling_event(iter, event->group_leader) {
2082 if (iter->aux_event != event)
2083 continue;
2084
2085 iter->aux_event = NULL;
2086 put_event(event);
2087
2088 /*
2089 * If it's ACTIVE, schedule it out and put it into ERROR
2090 * state so that we don't try to schedule it again. Note
2091 * that perf_event_enable() will clear the ERROR status.
2092 */
2093 event_sched_out(iter, ctx);
2094 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2095 }
2096 }
2097
perf_need_aux_event(struct perf_event * event)2098 static bool perf_need_aux_event(struct perf_event *event)
2099 {
2100 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2101 }
2102
perf_get_aux_event(struct perf_event * event,struct perf_event * group_leader)2103 static int perf_get_aux_event(struct perf_event *event,
2104 struct perf_event *group_leader)
2105 {
2106 /*
2107 * Our group leader must be an aux event if we want to be
2108 * an aux_output. This way, the aux event will precede its
2109 * aux_output events in the group, and therefore will always
2110 * schedule first.
2111 */
2112 if (!group_leader)
2113 return 0;
2114
2115 /*
2116 * aux_output and aux_sample_size are mutually exclusive.
2117 */
2118 if (event->attr.aux_output && event->attr.aux_sample_size)
2119 return 0;
2120
2121 if (event->attr.aux_output &&
2122 !perf_aux_output_match(event, group_leader))
2123 return 0;
2124
2125 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2126 return 0;
2127
2128 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2129 return 0;
2130
2131 /*
2132 * Link aux_outputs to their aux event; this is undone in
2133 * perf_group_detach() by perf_put_aux_event(). When the
2134 * group in torn down, the aux_output events loose their
2135 * link to the aux_event and can't schedule any more.
2136 */
2137 event->aux_event = group_leader;
2138
2139 return 1;
2140 }
2141
get_event_list(struct perf_event * event)2142 static inline struct list_head *get_event_list(struct perf_event *event)
2143 {
2144 return event->attr.pinned ? &event->pmu_ctx->pinned_active :
2145 &event->pmu_ctx->flexible_active;
2146 }
2147
2148 /*
2149 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2150 * cannot exist on their own, schedule them out and move them into the ERROR
2151 * state. Also see _perf_event_enable(), it will not be able to recover
2152 * this ERROR state.
2153 */
perf_remove_sibling_event(struct perf_event * event)2154 static inline void perf_remove_sibling_event(struct perf_event *event)
2155 {
2156 event_sched_out(event, event->ctx);
2157 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2158 }
2159
perf_group_detach(struct perf_event * event)2160 static void perf_group_detach(struct perf_event *event)
2161 {
2162 struct perf_event *leader = event->group_leader;
2163 struct perf_event *sibling, *tmp;
2164 struct perf_event_context *ctx = event->ctx;
2165
2166 lockdep_assert_held(&ctx->lock);
2167
2168 /*
2169 * We can have double detach due to exit/hot-unplug + close.
2170 */
2171 if (!(event->attach_state & PERF_ATTACH_GROUP))
2172 return;
2173
2174 event->attach_state &= ~PERF_ATTACH_GROUP;
2175
2176 perf_put_aux_event(event);
2177
2178 /*
2179 * If this is a sibling, remove it from its group.
2180 */
2181 if (leader != event) {
2182 list_del_init(&event->sibling_list);
2183 event->group_leader->nr_siblings--;
2184 event->group_leader->group_generation++;
2185 goto out;
2186 }
2187
2188 /*
2189 * If this was a group event with sibling events then
2190 * upgrade the siblings to singleton events by adding them
2191 * to whatever list we are on.
2192 */
2193 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2194
2195 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2196 perf_remove_sibling_event(sibling);
2197
2198 sibling->group_leader = sibling;
2199 list_del_init(&sibling->sibling_list);
2200
2201 /* Inherit group flags from the previous leader */
2202 sibling->group_caps = event->group_caps;
2203
2204 if (sibling->attach_state & PERF_ATTACH_CONTEXT) {
2205 add_event_to_groups(sibling, event->ctx);
2206
2207 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2208 list_add_tail(&sibling->active_list, get_event_list(sibling));
2209 }
2210
2211 WARN_ON_ONCE(sibling->ctx != event->ctx);
2212 }
2213
2214 out:
2215 for_each_sibling_event(tmp, leader)
2216 perf_event__header_size(tmp);
2217
2218 perf_event__header_size(leader);
2219 }
2220
2221 static void sync_child_event(struct perf_event *child_event);
2222
perf_child_detach(struct perf_event * event)2223 static void perf_child_detach(struct perf_event *event)
2224 {
2225 struct perf_event *parent_event = event->parent;
2226
2227 if (!(event->attach_state & PERF_ATTACH_CHILD))
2228 return;
2229
2230 event->attach_state &= ~PERF_ATTACH_CHILD;
2231
2232 if (WARN_ON_ONCE(!parent_event))
2233 return;
2234
2235 lockdep_assert_held(&parent_event->child_mutex);
2236
2237 sync_child_event(event);
2238 list_del_init(&event->child_list);
2239 }
2240
is_orphaned_event(struct perf_event * event)2241 static bool is_orphaned_event(struct perf_event *event)
2242 {
2243 return event->state == PERF_EVENT_STATE_DEAD;
2244 }
2245
2246 static inline int
event_filter_match(struct perf_event * event)2247 event_filter_match(struct perf_event *event)
2248 {
2249 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2250 perf_cgroup_match(event);
2251 }
2252
2253 static void
event_sched_out(struct perf_event * event,struct perf_event_context * ctx)2254 event_sched_out(struct perf_event *event, struct perf_event_context *ctx)
2255 {
2256 struct perf_event_pmu_context *epc = event->pmu_ctx;
2257 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2258 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2259
2260 // XXX cpc serialization, probably per-cpu IRQ disabled
2261
2262 WARN_ON_ONCE(event->ctx != ctx);
2263 lockdep_assert_held(&ctx->lock);
2264
2265 if (event->state != PERF_EVENT_STATE_ACTIVE)
2266 return;
2267
2268 /*
2269 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2270 * we can schedule events _OUT_ individually through things like
2271 * __perf_remove_from_context().
2272 */
2273 list_del_init(&event->active_list);
2274
2275 perf_pmu_disable(event->pmu);
2276
2277 event->pmu->del(event, 0);
2278 event->oncpu = -1;
2279
2280 if (event->pending_disable) {
2281 event->pending_disable = 0;
2282 perf_cgroup_event_disable(event, ctx);
2283 state = PERF_EVENT_STATE_OFF;
2284 }
2285
2286 if (event->pending_sigtrap) {
2287 bool dec = true;
2288
2289 event->pending_sigtrap = 0;
2290 if (state != PERF_EVENT_STATE_OFF &&
2291 !event->pending_work) {
2292 event->pending_work = 1;
2293 dec = false;
2294 WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
2295 task_work_add(current, &event->pending_task, TWA_RESUME);
2296 }
2297 if (dec)
2298 local_dec(&event->ctx->nr_pending);
2299 }
2300
2301 perf_event_set_state(event, state);
2302
2303 if (!is_software_event(event))
2304 cpc->active_oncpu--;
2305 if (event->attr.freq && event->attr.sample_freq) {
2306 ctx->nr_freq--;
2307 epc->nr_freq--;
2308 }
2309 if (event->attr.exclusive || !cpc->active_oncpu)
2310 cpc->exclusive = 0;
2311
2312 perf_pmu_enable(event->pmu);
2313 }
2314
2315 static void
group_sched_out(struct perf_event * group_event,struct perf_event_context * ctx)2316 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx)
2317 {
2318 struct perf_event *event;
2319
2320 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2321 return;
2322
2323 perf_assert_pmu_disabled(group_event->pmu_ctx->pmu);
2324
2325 event_sched_out(group_event, ctx);
2326
2327 /*
2328 * Schedule out siblings (if any):
2329 */
2330 for_each_sibling_event(event, group_event)
2331 event_sched_out(event, ctx);
2332 }
2333
2334 #define DETACH_GROUP 0x01UL
2335 #define DETACH_CHILD 0x02UL
2336 #define DETACH_DEAD 0x04UL
2337
2338 /*
2339 * Cross CPU call to remove a performance event
2340 *
2341 * We disable the event on the hardware level first. After that we
2342 * remove it from the context list.
2343 */
2344 static void
__perf_remove_from_context(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2345 __perf_remove_from_context(struct perf_event *event,
2346 struct perf_cpu_context *cpuctx,
2347 struct perf_event_context *ctx,
2348 void *info)
2349 {
2350 struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
2351 unsigned long flags = (unsigned long)info;
2352
2353 if (ctx->is_active & EVENT_TIME) {
2354 update_context_time(ctx);
2355 update_cgrp_time_from_cpuctx(cpuctx, false);
2356 }
2357
2358 /*
2359 * Ensure event_sched_out() switches to OFF, at the very least
2360 * this avoids raising perf_pending_task() at this time.
2361 */
2362 if (flags & DETACH_DEAD)
2363 event->pending_disable = 1;
2364 event_sched_out(event, ctx);
2365 if (flags & DETACH_GROUP)
2366 perf_group_detach(event);
2367 if (flags & DETACH_CHILD)
2368 perf_child_detach(event);
2369 list_del_event(event, ctx);
2370 if (flags & DETACH_DEAD)
2371 event->state = PERF_EVENT_STATE_DEAD;
2372
2373 if (!pmu_ctx->nr_events) {
2374 pmu_ctx->rotate_necessary = 0;
2375
2376 if (ctx->task && ctx->is_active) {
2377 struct perf_cpu_pmu_context *cpc;
2378
2379 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
2380 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
2381 cpc->task_epc = NULL;
2382 }
2383 }
2384
2385 if (!ctx->nr_events && ctx->is_active) {
2386 if (ctx == &cpuctx->ctx)
2387 update_cgrp_time_from_cpuctx(cpuctx, true);
2388
2389 ctx->is_active = 0;
2390 if (ctx->task) {
2391 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2392 cpuctx->task_ctx = NULL;
2393 }
2394 }
2395 }
2396
2397 /*
2398 * Remove the event from a task's (or a CPU's) list of events.
2399 *
2400 * If event->ctx is a cloned context, callers must make sure that
2401 * every task struct that event->ctx->task could possibly point to
2402 * remains valid. This is OK when called from perf_release since
2403 * that only calls us on the top-level context, which can't be a clone.
2404 * When called from perf_event_exit_task, it's OK because the
2405 * context has been detached from its task.
2406 */
perf_remove_from_context(struct perf_event * event,unsigned long flags)2407 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2408 {
2409 struct perf_event_context *ctx = event->ctx;
2410
2411 lockdep_assert_held(&ctx->mutex);
2412
2413 /*
2414 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2415 * to work in the face of TASK_TOMBSTONE, unlike every other
2416 * event_function_call() user.
2417 */
2418 raw_spin_lock_irq(&ctx->lock);
2419 if (!ctx->is_active) {
2420 __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context),
2421 ctx, (void *)flags);
2422 raw_spin_unlock_irq(&ctx->lock);
2423 return;
2424 }
2425 raw_spin_unlock_irq(&ctx->lock);
2426
2427 event_function_call(event, __perf_remove_from_context, (void *)flags);
2428 }
2429
2430 /*
2431 * Cross CPU call to disable a performance event
2432 */
__perf_event_disable(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2433 static void __perf_event_disable(struct perf_event *event,
2434 struct perf_cpu_context *cpuctx,
2435 struct perf_event_context *ctx,
2436 void *info)
2437 {
2438 if (event->state < PERF_EVENT_STATE_INACTIVE)
2439 return;
2440
2441 if (ctx->is_active & EVENT_TIME) {
2442 update_context_time(ctx);
2443 update_cgrp_time_from_event(event);
2444 }
2445
2446 perf_pmu_disable(event->pmu_ctx->pmu);
2447
2448 if (event == event->group_leader)
2449 group_sched_out(event, ctx);
2450 else
2451 event_sched_out(event, ctx);
2452
2453 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2454 perf_cgroup_event_disable(event, ctx);
2455
2456 perf_pmu_enable(event->pmu_ctx->pmu);
2457 }
2458
2459 /*
2460 * Disable an event.
2461 *
2462 * If event->ctx is a cloned context, callers must make sure that
2463 * every task struct that event->ctx->task could possibly point to
2464 * remains valid. This condition is satisfied when called through
2465 * perf_event_for_each_child or perf_event_for_each because they
2466 * hold the top-level event's child_mutex, so any descendant that
2467 * goes to exit will block in perf_event_exit_event().
2468 *
2469 * When called from perf_pending_irq it's OK because event->ctx
2470 * is the current context on this CPU and preemption is disabled,
2471 * hence we can't get into perf_event_task_sched_out for this context.
2472 */
_perf_event_disable(struct perf_event * event)2473 static void _perf_event_disable(struct perf_event *event)
2474 {
2475 struct perf_event_context *ctx = event->ctx;
2476
2477 raw_spin_lock_irq(&ctx->lock);
2478 if (event->state <= PERF_EVENT_STATE_OFF) {
2479 raw_spin_unlock_irq(&ctx->lock);
2480 return;
2481 }
2482 raw_spin_unlock_irq(&ctx->lock);
2483
2484 event_function_call(event, __perf_event_disable, NULL);
2485 }
2486
perf_event_disable_local(struct perf_event * event)2487 void perf_event_disable_local(struct perf_event *event)
2488 {
2489 event_function_local(event, __perf_event_disable, NULL);
2490 }
2491
2492 /*
2493 * Strictly speaking kernel users cannot create groups and therefore this
2494 * interface does not need the perf_event_ctx_lock() magic.
2495 */
perf_event_disable(struct perf_event * event)2496 void perf_event_disable(struct perf_event *event)
2497 {
2498 struct perf_event_context *ctx;
2499
2500 ctx = perf_event_ctx_lock(event);
2501 _perf_event_disable(event);
2502 perf_event_ctx_unlock(event, ctx);
2503 }
2504 EXPORT_SYMBOL_GPL(perf_event_disable);
2505
perf_event_disable_inatomic(struct perf_event * event)2506 void perf_event_disable_inatomic(struct perf_event *event)
2507 {
2508 event->pending_disable = 1;
2509 irq_work_queue(&event->pending_irq);
2510 }
2511
2512 #define MAX_INTERRUPTS (~0ULL)
2513
2514 static void perf_log_throttle(struct perf_event *event, int enable);
2515 static void perf_log_itrace_start(struct perf_event *event);
2516
2517 static int
event_sched_in(struct perf_event * event,struct perf_event_context * ctx)2518 event_sched_in(struct perf_event *event, struct perf_event_context *ctx)
2519 {
2520 struct perf_event_pmu_context *epc = event->pmu_ctx;
2521 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2522 int ret = 0;
2523
2524 WARN_ON_ONCE(event->ctx != ctx);
2525
2526 lockdep_assert_held(&ctx->lock);
2527
2528 if (event->state <= PERF_EVENT_STATE_OFF)
2529 return 0;
2530
2531 WRITE_ONCE(event->oncpu, smp_processor_id());
2532 /*
2533 * Order event::oncpu write to happen before the ACTIVE state is
2534 * visible. This allows perf_event_{stop,read}() to observe the correct
2535 * ->oncpu if it sees ACTIVE.
2536 */
2537 smp_wmb();
2538 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2539
2540 /*
2541 * Unthrottle events, since we scheduled we might have missed several
2542 * ticks already, also for a heavily scheduling task there is little
2543 * guarantee it'll get a tick in a timely manner.
2544 */
2545 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2546 perf_log_throttle(event, 1);
2547 event->hw.interrupts = 0;
2548 }
2549
2550 perf_pmu_disable(event->pmu);
2551
2552 perf_log_itrace_start(event);
2553
2554 if (event->pmu->add(event, PERF_EF_START)) {
2555 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2556 event->oncpu = -1;
2557 ret = -EAGAIN;
2558 goto out;
2559 }
2560
2561 if (!is_software_event(event))
2562 cpc->active_oncpu++;
2563 if (event->attr.freq && event->attr.sample_freq) {
2564 ctx->nr_freq++;
2565 epc->nr_freq++;
2566 }
2567 if (event->attr.exclusive)
2568 cpc->exclusive = 1;
2569
2570 out:
2571 perf_pmu_enable(event->pmu);
2572
2573 return ret;
2574 }
2575
2576 static int
group_sched_in(struct perf_event * group_event,struct perf_event_context * ctx)2577 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx)
2578 {
2579 struct perf_event *event, *partial_group = NULL;
2580 struct pmu *pmu = group_event->pmu_ctx->pmu;
2581
2582 if (group_event->state == PERF_EVENT_STATE_OFF)
2583 return 0;
2584
2585 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2586
2587 if (event_sched_in(group_event, ctx))
2588 goto error;
2589
2590 /*
2591 * Schedule in siblings as one group (if any):
2592 */
2593 for_each_sibling_event(event, group_event) {
2594 if (event_sched_in(event, ctx)) {
2595 partial_group = event;
2596 goto group_error;
2597 }
2598 }
2599
2600 if (!pmu->commit_txn(pmu))
2601 return 0;
2602
2603 group_error:
2604 /*
2605 * Groups can be scheduled in as one unit only, so undo any
2606 * partial group before returning:
2607 * The events up to the failed event are scheduled out normally.
2608 */
2609 for_each_sibling_event(event, group_event) {
2610 if (event == partial_group)
2611 break;
2612
2613 event_sched_out(event, ctx);
2614 }
2615 event_sched_out(group_event, ctx);
2616
2617 error:
2618 pmu->cancel_txn(pmu);
2619 return -EAGAIN;
2620 }
2621
2622 /*
2623 * Work out whether we can put this event group on the CPU now.
2624 */
group_can_go_on(struct perf_event * event,int can_add_hw)2625 static int group_can_go_on(struct perf_event *event, int can_add_hw)
2626 {
2627 struct perf_event_pmu_context *epc = event->pmu_ctx;
2628 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2629
2630 /*
2631 * Groups consisting entirely of software events can always go on.
2632 */
2633 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2634 return 1;
2635 /*
2636 * If an exclusive group is already on, no other hardware
2637 * events can go on.
2638 */
2639 if (cpc->exclusive)
2640 return 0;
2641 /*
2642 * If this group is exclusive and there are already
2643 * events on the CPU, it can't go on.
2644 */
2645 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2646 return 0;
2647 /*
2648 * Otherwise, try to add it if all previous groups were able
2649 * to go on.
2650 */
2651 return can_add_hw;
2652 }
2653
add_event_to_ctx(struct perf_event * event,struct perf_event_context * ctx)2654 static void add_event_to_ctx(struct perf_event *event,
2655 struct perf_event_context *ctx)
2656 {
2657 list_add_event(event, ctx);
2658 perf_group_attach(event);
2659 }
2660
task_ctx_sched_out(struct perf_event_context * ctx,enum event_type_t event_type)2661 static void task_ctx_sched_out(struct perf_event_context *ctx,
2662 enum event_type_t event_type)
2663 {
2664 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2665
2666 if (!cpuctx->task_ctx)
2667 return;
2668
2669 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2670 return;
2671
2672 ctx_sched_out(ctx, event_type);
2673 }
2674
perf_event_sched_in(struct perf_cpu_context * cpuctx,struct perf_event_context * ctx)2675 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2676 struct perf_event_context *ctx)
2677 {
2678 ctx_sched_in(&cpuctx->ctx, EVENT_PINNED);
2679 if (ctx)
2680 ctx_sched_in(ctx, EVENT_PINNED);
2681 ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE);
2682 if (ctx)
2683 ctx_sched_in(ctx, EVENT_FLEXIBLE);
2684 }
2685
2686 /*
2687 * We want to maintain the following priority of scheduling:
2688 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2689 * - task pinned (EVENT_PINNED)
2690 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2691 * - task flexible (EVENT_FLEXIBLE).
2692 *
2693 * In order to avoid unscheduling and scheduling back in everything every
2694 * time an event is added, only do it for the groups of equal priority and
2695 * below.
2696 *
2697 * This can be called after a batch operation on task events, in which case
2698 * event_type is a bit mask of the types of events involved. For CPU events,
2699 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2700 */
2701 /*
2702 * XXX: ctx_resched() reschedule entire perf_event_context while adding new
2703 * event to the context or enabling existing event in the context. We can
2704 * probably optimize it by rescheduling only affected pmu_ctx.
2705 */
ctx_resched(struct perf_cpu_context * cpuctx,struct perf_event_context * task_ctx,enum event_type_t event_type)2706 static void ctx_resched(struct perf_cpu_context *cpuctx,
2707 struct perf_event_context *task_ctx,
2708 enum event_type_t event_type)
2709 {
2710 bool cpu_event = !!(event_type & EVENT_CPU);
2711
2712 /*
2713 * If pinned groups are involved, flexible groups also need to be
2714 * scheduled out.
2715 */
2716 if (event_type & EVENT_PINNED)
2717 event_type |= EVENT_FLEXIBLE;
2718
2719 event_type &= EVENT_ALL;
2720
2721 perf_ctx_disable(&cpuctx->ctx, false);
2722 if (task_ctx) {
2723 perf_ctx_disable(task_ctx, false);
2724 task_ctx_sched_out(task_ctx, event_type);
2725 }
2726
2727 /*
2728 * Decide which cpu ctx groups to schedule out based on the types
2729 * of events that caused rescheduling:
2730 * - EVENT_CPU: schedule out corresponding groups;
2731 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2732 * - otherwise, do nothing more.
2733 */
2734 if (cpu_event)
2735 ctx_sched_out(&cpuctx->ctx, event_type);
2736 else if (event_type & EVENT_PINNED)
2737 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
2738
2739 perf_event_sched_in(cpuctx, task_ctx);
2740
2741 perf_ctx_enable(&cpuctx->ctx, false);
2742 if (task_ctx)
2743 perf_ctx_enable(task_ctx, false);
2744 }
2745
perf_pmu_resched(struct pmu * pmu)2746 void perf_pmu_resched(struct pmu *pmu)
2747 {
2748 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2749 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2750
2751 perf_ctx_lock(cpuctx, task_ctx);
2752 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2753 perf_ctx_unlock(cpuctx, task_ctx);
2754 }
2755
2756 /*
2757 * Cross CPU call to install and enable a performance event
2758 *
2759 * Very similar to remote_function() + event_function() but cannot assume that
2760 * things like ctx->is_active and cpuctx->task_ctx are set.
2761 */
__perf_install_in_context(void * info)2762 static int __perf_install_in_context(void *info)
2763 {
2764 struct perf_event *event = info;
2765 struct perf_event_context *ctx = event->ctx;
2766 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2767 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2768 bool reprogram = true;
2769 int ret = 0;
2770
2771 raw_spin_lock(&cpuctx->ctx.lock);
2772 if (ctx->task) {
2773 raw_spin_lock(&ctx->lock);
2774 task_ctx = ctx;
2775
2776 reprogram = (ctx->task == current);
2777
2778 /*
2779 * If the task is running, it must be running on this CPU,
2780 * otherwise we cannot reprogram things.
2781 *
2782 * If its not running, we don't care, ctx->lock will
2783 * serialize against it becoming runnable.
2784 */
2785 if (task_curr(ctx->task) && !reprogram) {
2786 ret = -ESRCH;
2787 goto unlock;
2788 }
2789
2790 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2791 } else if (task_ctx) {
2792 raw_spin_lock(&task_ctx->lock);
2793 }
2794
2795 #ifdef CONFIG_CGROUP_PERF
2796 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2797 /*
2798 * If the current cgroup doesn't match the event's
2799 * cgroup, we should not try to schedule it.
2800 */
2801 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2802 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2803 event->cgrp->css.cgroup);
2804 }
2805 #endif
2806
2807 if (reprogram) {
2808 ctx_sched_out(ctx, EVENT_TIME);
2809 add_event_to_ctx(event, ctx);
2810 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2811 } else {
2812 add_event_to_ctx(event, ctx);
2813 }
2814
2815 unlock:
2816 perf_ctx_unlock(cpuctx, task_ctx);
2817
2818 return ret;
2819 }
2820
2821 static bool exclusive_event_installable(struct perf_event *event,
2822 struct perf_event_context *ctx);
2823
2824 /*
2825 * Attach a performance event to a context.
2826 *
2827 * Very similar to event_function_call, see comment there.
2828 */
2829 static void
perf_install_in_context(struct perf_event_context * ctx,struct perf_event * event,int cpu)2830 perf_install_in_context(struct perf_event_context *ctx,
2831 struct perf_event *event,
2832 int cpu)
2833 {
2834 struct task_struct *task = READ_ONCE(ctx->task);
2835
2836 lockdep_assert_held(&ctx->mutex);
2837
2838 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2839
2840 if (event->cpu != -1)
2841 WARN_ON_ONCE(event->cpu != cpu);
2842
2843 /*
2844 * Ensures that if we can observe event->ctx, both the event and ctx
2845 * will be 'complete'. See perf_iterate_sb_cpu().
2846 */
2847 smp_store_release(&event->ctx, ctx);
2848
2849 /*
2850 * perf_event_attr::disabled events will not run and can be initialized
2851 * without IPI. Except when this is the first event for the context, in
2852 * that case we need the magic of the IPI to set ctx->is_active.
2853 *
2854 * The IOC_ENABLE that is sure to follow the creation of a disabled
2855 * event will issue the IPI and reprogram the hardware.
2856 */
2857 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2858 ctx->nr_events && !is_cgroup_event(event)) {
2859 raw_spin_lock_irq(&ctx->lock);
2860 if (ctx->task == TASK_TOMBSTONE) {
2861 raw_spin_unlock_irq(&ctx->lock);
2862 return;
2863 }
2864 add_event_to_ctx(event, ctx);
2865 raw_spin_unlock_irq(&ctx->lock);
2866 return;
2867 }
2868
2869 if (!task) {
2870 cpu_function_call(cpu, __perf_install_in_context, event);
2871 return;
2872 }
2873
2874 /*
2875 * Should not happen, we validate the ctx is still alive before calling.
2876 */
2877 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2878 return;
2879
2880 /*
2881 * Installing events is tricky because we cannot rely on ctx->is_active
2882 * to be set in case this is the nr_events 0 -> 1 transition.
2883 *
2884 * Instead we use task_curr(), which tells us if the task is running.
2885 * However, since we use task_curr() outside of rq::lock, we can race
2886 * against the actual state. This means the result can be wrong.
2887 *
2888 * If we get a false positive, we retry, this is harmless.
2889 *
2890 * If we get a false negative, things are complicated. If we are after
2891 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2892 * value must be correct. If we're before, it doesn't matter since
2893 * perf_event_context_sched_in() will program the counter.
2894 *
2895 * However, this hinges on the remote context switch having observed
2896 * our task->perf_event_ctxp[] store, such that it will in fact take
2897 * ctx::lock in perf_event_context_sched_in().
2898 *
2899 * We do this by task_function_call(), if the IPI fails to hit the task
2900 * we know any future context switch of task must see the
2901 * perf_event_ctpx[] store.
2902 */
2903
2904 /*
2905 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2906 * task_cpu() load, such that if the IPI then does not find the task
2907 * running, a future context switch of that task must observe the
2908 * store.
2909 */
2910 smp_mb();
2911 again:
2912 if (!task_function_call(task, __perf_install_in_context, event))
2913 return;
2914
2915 raw_spin_lock_irq(&ctx->lock);
2916 task = ctx->task;
2917 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2918 /*
2919 * Cannot happen because we already checked above (which also
2920 * cannot happen), and we hold ctx->mutex, which serializes us
2921 * against perf_event_exit_task_context().
2922 */
2923 raw_spin_unlock_irq(&ctx->lock);
2924 return;
2925 }
2926 /*
2927 * If the task is not running, ctx->lock will avoid it becoming so,
2928 * thus we can safely install the event.
2929 */
2930 if (task_curr(task)) {
2931 raw_spin_unlock_irq(&ctx->lock);
2932 goto again;
2933 }
2934 add_event_to_ctx(event, ctx);
2935 raw_spin_unlock_irq(&ctx->lock);
2936 }
2937
2938 /*
2939 * Cross CPU call to enable a performance event
2940 */
__perf_event_enable(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)2941 static void __perf_event_enable(struct perf_event *event,
2942 struct perf_cpu_context *cpuctx,
2943 struct perf_event_context *ctx,
2944 void *info)
2945 {
2946 struct perf_event *leader = event->group_leader;
2947 struct perf_event_context *task_ctx;
2948
2949 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2950 event->state <= PERF_EVENT_STATE_ERROR)
2951 return;
2952
2953 if (ctx->is_active)
2954 ctx_sched_out(ctx, EVENT_TIME);
2955
2956 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2957 perf_cgroup_event_enable(event, ctx);
2958
2959 if (!ctx->is_active)
2960 return;
2961
2962 if (!event_filter_match(event)) {
2963 ctx_sched_in(ctx, EVENT_TIME);
2964 return;
2965 }
2966
2967 /*
2968 * If the event is in a group and isn't the group leader,
2969 * then don't put it on unless the group is on.
2970 */
2971 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2972 ctx_sched_in(ctx, EVENT_TIME);
2973 return;
2974 }
2975
2976 task_ctx = cpuctx->task_ctx;
2977 if (ctx->task)
2978 WARN_ON_ONCE(task_ctx != ctx);
2979
2980 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2981 }
2982
2983 /*
2984 * Enable an event.
2985 *
2986 * If event->ctx is a cloned context, callers must make sure that
2987 * every task struct that event->ctx->task could possibly point to
2988 * remains valid. This condition is satisfied when called through
2989 * perf_event_for_each_child or perf_event_for_each as described
2990 * for perf_event_disable.
2991 */
_perf_event_enable(struct perf_event * event)2992 static void _perf_event_enable(struct perf_event *event)
2993 {
2994 struct perf_event_context *ctx = event->ctx;
2995
2996 raw_spin_lock_irq(&ctx->lock);
2997 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2998 event->state < PERF_EVENT_STATE_ERROR) {
2999 out:
3000 raw_spin_unlock_irq(&ctx->lock);
3001 return;
3002 }
3003
3004 /*
3005 * If the event is in error state, clear that first.
3006 *
3007 * That way, if we see the event in error state below, we know that it
3008 * has gone back into error state, as distinct from the task having
3009 * been scheduled away before the cross-call arrived.
3010 */
3011 if (event->state == PERF_EVENT_STATE_ERROR) {
3012 /*
3013 * Detached SIBLING events cannot leave ERROR state.
3014 */
3015 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3016 event->group_leader == event)
3017 goto out;
3018
3019 event->state = PERF_EVENT_STATE_OFF;
3020 }
3021 raw_spin_unlock_irq(&ctx->lock);
3022
3023 event_function_call(event, __perf_event_enable, NULL);
3024 }
3025
3026 /*
3027 * See perf_event_disable();
3028 */
perf_event_enable(struct perf_event * event)3029 void perf_event_enable(struct perf_event *event)
3030 {
3031 struct perf_event_context *ctx;
3032
3033 ctx = perf_event_ctx_lock(event);
3034 _perf_event_enable(event);
3035 perf_event_ctx_unlock(event, ctx);
3036 }
3037 EXPORT_SYMBOL_GPL(perf_event_enable);
3038
3039 struct stop_event_data {
3040 struct perf_event *event;
3041 unsigned int restart;
3042 };
3043
__perf_event_stop(void * info)3044 static int __perf_event_stop(void *info)
3045 {
3046 struct stop_event_data *sd = info;
3047 struct perf_event *event = sd->event;
3048
3049 /* if it's already INACTIVE, do nothing */
3050 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3051 return 0;
3052
3053 /* matches smp_wmb() in event_sched_in() */
3054 smp_rmb();
3055
3056 /*
3057 * There is a window with interrupts enabled before we get here,
3058 * so we need to check again lest we try to stop another CPU's event.
3059 */
3060 if (READ_ONCE(event->oncpu) != smp_processor_id())
3061 return -EAGAIN;
3062
3063 event->pmu->stop(event, PERF_EF_UPDATE);
3064
3065 /*
3066 * May race with the actual stop (through perf_pmu_output_stop()),
3067 * but it is only used for events with AUX ring buffer, and such
3068 * events will refuse to restart because of rb::aux_mmap_count==0,
3069 * see comments in perf_aux_output_begin().
3070 *
3071 * Since this is happening on an event-local CPU, no trace is lost
3072 * while restarting.
3073 */
3074 if (sd->restart)
3075 event->pmu->start(event, 0);
3076
3077 return 0;
3078 }
3079
perf_event_stop(struct perf_event * event,int restart)3080 static int perf_event_stop(struct perf_event *event, int restart)
3081 {
3082 struct stop_event_data sd = {
3083 .event = event,
3084 .restart = restart,
3085 };
3086 int ret = 0;
3087
3088 do {
3089 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3090 return 0;
3091
3092 /* matches smp_wmb() in event_sched_in() */
3093 smp_rmb();
3094
3095 /*
3096 * We only want to restart ACTIVE events, so if the event goes
3097 * inactive here (event->oncpu==-1), there's nothing more to do;
3098 * fall through with ret==-ENXIO.
3099 */
3100 ret = cpu_function_call(READ_ONCE(event->oncpu),
3101 __perf_event_stop, &sd);
3102 } while (ret == -EAGAIN);
3103
3104 return ret;
3105 }
3106
3107 /*
3108 * In order to contain the amount of racy and tricky in the address filter
3109 * configuration management, it is a two part process:
3110 *
3111 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3112 * we update the addresses of corresponding vmas in
3113 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3114 * (p2) when an event is scheduled in (pmu::add), it calls
3115 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3116 * if the generation has changed since the previous call.
3117 *
3118 * If (p1) happens while the event is active, we restart it to force (p2).
3119 *
3120 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3121 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3122 * ioctl;
3123 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3124 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3125 * for reading;
3126 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3127 * of exec.
3128 */
perf_event_addr_filters_sync(struct perf_event * event)3129 void perf_event_addr_filters_sync(struct perf_event *event)
3130 {
3131 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3132
3133 if (!has_addr_filter(event))
3134 return;
3135
3136 raw_spin_lock(&ifh->lock);
3137 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3138 event->pmu->addr_filters_sync(event);
3139 event->hw.addr_filters_gen = event->addr_filters_gen;
3140 }
3141 raw_spin_unlock(&ifh->lock);
3142 }
3143 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3144
_perf_event_refresh(struct perf_event * event,int refresh)3145 static int _perf_event_refresh(struct perf_event *event, int refresh)
3146 {
3147 /*
3148 * not supported on inherited events
3149 */
3150 if (event->attr.inherit || !is_sampling_event(event))
3151 return -EINVAL;
3152
3153 atomic_add(refresh, &event->event_limit);
3154 _perf_event_enable(event);
3155
3156 return 0;
3157 }
3158
3159 /*
3160 * See perf_event_disable()
3161 */
perf_event_refresh(struct perf_event * event,int refresh)3162 int perf_event_refresh(struct perf_event *event, int refresh)
3163 {
3164 struct perf_event_context *ctx;
3165 int ret;
3166
3167 ctx = perf_event_ctx_lock(event);
3168 ret = _perf_event_refresh(event, refresh);
3169 perf_event_ctx_unlock(event, ctx);
3170
3171 return ret;
3172 }
3173 EXPORT_SYMBOL_GPL(perf_event_refresh);
3174
perf_event_modify_breakpoint(struct perf_event * bp,struct perf_event_attr * attr)3175 static int perf_event_modify_breakpoint(struct perf_event *bp,
3176 struct perf_event_attr *attr)
3177 {
3178 int err;
3179
3180 _perf_event_disable(bp);
3181
3182 err = modify_user_hw_breakpoint_check(bp, attr, true);
3183
3184 if (!bp->attr.disabled)
3185 _perf_event_enable(bp);
3186
3187 return err;
3188 }
3189
3190 /*
3191 * Copy event-type-independent attributes that may be modified.
3192 */
perf_event_modify_copy_attr(struct perf_event_attr * to,const struct perf_event_attr * from)3193 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3194 const struct perf_event_attr *from)
3195 {
3196 to->sig_data = from->sig_data;
3197 }
3198
perf_event_modify_attr(struct perf_event * event,struct perf_event_attr * attr)3199 static int perf_event_modify_attr(struct perf_event *event,
3200 struct perf_event_attr *attr)
3201 {
3202 int (*func)(struct perf_event *, struct perf_event_attr *);
3203 struct perf_event *child;
3204 int err;
3205
3206 if (event->attr.type != attr->type)
3207 return -EINVAL;
3208
3209 switch (event->attr.type) {
3210 case PERF_TYPE_BREAKPOINT:
3211 func = perf_event_modify_breakpoint;
3212 break;
3213 default:
3214 /* Place holder for future additions. */
3215 return -EOPNOTSUPP;
3216 }
3217
3218 WARN_ON_ONCE(event->ctx->parent_ctx);
3219
3220 mutex_lock(&event->child_mutex);
3221 /*
3222 * Event-type-independent attributes must be copied before event-type
3223 * modification, which will validate that final attributes match the
3224 * source attributes after all relevant attributes have been copied.
3225 */
3226 perf_event_modify_copy_attr(&event->attr, attr);
3227 err = func(event, attr);
3228 if (err)
3229 goto out;
3230 list_for_each_entry(child, &event->child_list, child_list) {
3231 perf_event_modify_copy_attr(&child->attr, attr);
3232 err = func(child, attr);
3233 if (err)
3234 goto out;
3235 }
3236 out:
3237 mutex_unlock(&event->child_mutex);
3238 return err;
3239 }
3240
__pmu_ctx_sched_out(struct perf_event_pmu_context * pmu_ctx,enum event_type_t event_type)3241 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx,
3242 enum event_type_t event_type)
3243 {
3244 struct perf_event_context *ctx = pmu_ctx->ctx;
3245 struct perf_event *event, *tmp;
3246 struct pmu *pmu = pmu_ctx->pmu;
3247
3248 if (ctx->task && !ctx->is_active) {
3249 struct perf_cpu_pmu_context *cpc;
3250
3251 cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3252 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3253 cpc->task_epc = NULL;
3254 }
3255
3256 if (!event_type)
3257 return;
3258
3259 perf_pmu_disable(pmu);
3260 if (event_type & EVENT_PINNED) {
3261 list_for_each_entry_safe(event, tmp,
3262 &pmu_ctx->pinned_active,
3263 active_list)
3264 group_sched_out(event, ctx);
3265 }
3266
3267 if (event_type & EVENT_FLEXIBLE) {
3268 list_for_each_entry_safe(event, tmp,
3269 &pmu_ctx->flexible_active,
3270 active_list)
3271 group_sched_out(event, ctx);
3272 /*
3273 * Since we cleared EVENT_FLEXIBLE, also clear
3274 * rotate_necessary, is will be reset by
3275 * ctx_flexible_sched_in() when needed.
3276 */
3277 pmu_ctx->rotate_necessary = 0;
3278 }
3279 perf_pmu_enable(pmu);
3280 }
3281
3282 static void
ctx_sched_out(struct perf_event_context * ctx,enum event_type_t event_type)3283 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type)
3284 {
3285 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3286 struct perf_event_pmu_context *pmu_ctx;
3287 int is_active = ctx->is_active;
3288 bool cgroup = event_type & EVENT_CGROUP;
3289
3290 event_type &= ~EVENT_CGROUP;
3291
3292 lockdep_assert_held(&ctx->lock);
3293
3294 if (likely(!ctx->nr_events)) {
3295 /*
3296 * See __perf_remove_from_context().
3297 */
3298 WARN_ON_ONCE(ctx->is_active);
3299 if (ctx->task)
3300 WARN_ON_ONCE(cpuctx->task_ctx);
3301 return;
3302 }
3303
3304 /*
3305 * Always update time if it was set; not only when it changes.
3306 * Otherwise we can 'forget' to update time for any but the last
3307 * context we sched out. For example:
3308 *
3309 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3310 * ctx_sched_out(.event_type = EVENT_PINNED)
3311 *
3312 * would only update time for the pinned events.
3313 */
3314 if (is_active & EVENT_TIME) {
3315 /* update (and stop) ctx time */
3316 update_context_time(ctx);
3317 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3318 /*
3319 * CPU-release for the below ->is_active store,
3320 * see __load_acquire() in perf_event_time_now()
3321 */
3322 barrier();
3323 }
3324
3325 ctx->is_active &= ~event_type;
3326 if (!(ctx->is_active & EVENT_ALL))
3327 ctx->is_active = 0;
3328
3329 if (ctx->task) {
3330 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3331 if (!ctx->is_active)
3332 cpuctx->task_ctx = NULL;
3333 }
3334
3335 is_active ^= ctx->is_active; /* changed bits */
3336
3337 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3338 if (cgroup && !pmu_ctx->nr_cgroups)
3339 continue;
3340 __pmu_ctx_sched_out(pmu_ctx, is_active);
3341 }
3342 }
3343
3344 /*
3345 * Test whether two contexts are equivalent, i.e. whether they have both been
3346 * cloned from the same version of the same context.
3347 *
3348 * Equivalence is measured using a generation number in the context that is
3349 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3350 * and list_del_event().
3351 */
context_equiv(struct perf_event_context * ctx1,struct perf_event_context * ctx2)3352 static int context_equiv(struct perf_event_context *ctx1,
3353 struct perf_event_context *ctx2)
3354 {
3355 lockdep_assert_held(&ctx1->lock);
3356 lockdep_assert_held(&ctx2->lock);
3357
3358 /* Pinning disables the swap optimization */
3359 if (ctx1->pin_count || ctx2->pin_count)
3360 return 0;
3361
3362 /* If ctx1 is the parent of ctx2 */
3363 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3364 return 1;
3365
3366 /* If ctx2 is the parent of ctx1 */
3367 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3368 return 1;
3369
3370 /*
3371 * If ctx1 and ctx2 have the same parent; we flatten the parent
3372 * hierarchy, see perf_event_init_context().
3373 */
3374 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3375 ctx1->parent_gen == ctx2->parent_gen)
3376 return 1;
3377
3378 /* Unmatched */
3379 return 0;
3380 }
3381
__perf_event_sync_stat(struct perf_event * event,struct perf_event * next_event)3382 static void __perf_event_sync_stat(struct perf_event *event,
3383 struct perf_event *next_event)
3384 {
3385 u64 value;
3386
3387 if (!event->attr.inherit_stat)
3388 return;
3389
3390 /*
3391 * Update the event value, we cannot use perf_event_read()
3392 * because we're in the middle of a context switch and have IRQs
3393 * disabled, which upsets smp_call_function_single(), however
3394 * we know the event must be on the current CPU, therefore we
3395 * don't need to use it.
3396 */
3397 if (event->state == PERF_EVENT_STATE_ACTIVE)
3398 event->pmu->read(event);
3399
3400 perf_event_update_time(event);
3401
3402 /*
3403 * In order to keep per-task stats reliable we need to flip the event
3404 * values when we flip the contexts.
3405 */
3406 value = local64_read(&next_event->count);
3407 value = local64_xchg(&event->count, value);
3408 local64_set(&next_event->count, value);
3409
3410 swap(event->total_time_enabled, next_event->total_time_enabled);
3411 swap(event->total_time_running, next_event->total_time_running);
3412
3413 /*
3414 * Since we swizzled the values, update the user visible data too.
3415 */
3416 perf_event_update_userpage(event);
3417 perf_event_update_userpage(next_event);
3418 }
3419
perf_event_sync_stat(struct perf_event_context * ctx,struct perf_event_context * next_ctx)3420 static void perf_event_sync_stat(struct perf_event_context *ctx,
3421 struct perf_event_context *next_ctx)
3422 {
3423 struct perf_event *event, *next_event;
3424
3425 if (!ctx->nr_stat)
3426 return;
3427
3428 update_context_time(ctx);
3429
3430 event = list_first_entry(&ctx->event_list,
3431 struct perf_event, event_entry);
3432
3433 next_event = list_first_entry(&next_ctx->event_list,
3434 struct perf_event, event_entry);
3435
3436 while (&event->event_entry != &ctx->event_list &&
3437 &next_event->event_entry != &next_ctx->event_list) {
3438
3439 __perf_event_sync_stat(event, next_event);
3440
3441 event = list_next_entry(event, event_entry);
3442 next_event = list_next_entry(next_event, event_entry);
3443 }
3444 }
3445
3446 #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \
3447 for (pos1 = list_first_entry(head1, typeof(*pos1), member), \
3448 pos2 = list_first_entry(head2, typeof(*pos2), member); \
3449 !list_entry_is_head(pos1, head1, member) && \
3450 !list_entry_is_head(pos2, head2, member); \
3451 pos1 = list_next_entry(pos1, member), \
3452 pos2 = list_next_entry(pos2, member))
3453
perf_event_swap_task_ctx_data(struct perf_event_context * prev_ctx,struct perf_event_context * next_ctx)3454 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
3455 struct perf_event_context *next_ctx)
3456 {
3457 struct perf_event_pmu_context *prev_epc, *next_epc;
3458
3459 if (!prev_ctx->nr_task_data)
3460 return;
3461
3462 double_list_for_each_entry(prev_epc, next_epc,
3463 &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list,
3464 pmu_ctx_entry) {
3465
3466 if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu))
3467 continue;
3468
3469 /*
3470 * PMU specific parts of task perf context can require
3471 * additional synchronization. As an example of such
3472 * synchronization see implementation details of Intel
3473 * LBR call stack data profiling;
3474 */
3475 if (prev_epc->pmu->swap_task_ctx)
3476 prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
3477 else
3478 swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
3479 }
3480 }
3481
perf_ctx_sched_task_cb(struct perf_event_context * ctx,bool sched_in)3482 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in)
3483 {
3484 struct perf_event_pmu_context *pmu_ctx;
3485 struct perf_cpu_pmu_context *cpc;
3486
3487 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3488 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3489
3490 if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task)
3491 pmu_ctx->pmu->sched_task(pmu_ctx, sched_in);
3492 }
3493 }
3494
3495 static void
perf_event_context_sched_out(struct task_struct * task,struct task_struct * next)3496 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
3497 {
3498 struct perf_event_context *ctx = task->perf_event_ctxp;
3499 struct perf_event_context *next_ctx;
3500 struct perf_event_context *parent, *next_parent;
3501 int do_switch = 1;
3502
3503 if (likely(!ctx))
3504 return;
3505
3506 rcu_read_lock();
3507 next_ctx = rcu_dereference(next->perf_event_ctxp);
3508 if (!next_ctx)
3509 goto unlock;
3510
3511 parent = rcu_dereference(ctx->parent_ctx);
3512 next_parent = rcu_dereference(next_ctx->parent_ctx);
3513
3514 /* If neither context have a parent context; they cannot be clones. */
3515 if (!parent && !next_parent)
3516 goto unlock;
3517
3518 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3519 /*
3520 * Looks like the two contexts are clones, so we might be
3521 * able to optimize the context switch. We lock both
3522 * contexts and check that they are clones under the
3523 * lock (including re-checking that neither has been
3524 * uncloned in the meantime). It doesn't matter which
3525 * order we take the locks because no other cpu could
3526 * be trying to lock both of these tasks.
3527 */
3528 raw_spin_lock(&ctx->lock);
3529 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3530 if (context_equiv(ctx, next_ctx)) {
3531
3532 perf_ctx_disable(ctx, false);
3533
3534 /* PMIs are disabled; ctx->nr_pending is stable. */
3535 if (local_read(&ctx->nr_pending) ||
3536 local_read(&next_ctx->nr_pending)) {
3537 /*
3538 * Must not swap out ctx when there's pending
3539 * events that rely on the ctx->task relation.
3540 */
3541 raw_spin_unlock(&next_ctx->lock);
3542 rcu_read_unlock();
3543 goto inside_switch;
3544 }
3545
3546 WRITE_ONCE(ctx->task, next);
3547 WRITE_ONCE(next_ctx->task, task);
3548
3549 perf_ctx_sched_task_cb(ctx, false);
3550 perf_event_swap_task_ctx_data(ctx, next_ctx);
3551
3552 perf_ctx_enable(ctx, false);
3553
3554 /*
3555 * RCU_INIT_POINTER here is safe because we've not
3556 * modified the ctx and the above modification of
3557 * ctx->task and ctx->task_ctx_data are immaterial
3558 * since those values are always verified under
3559 * ctx->lock which we're now holding.
3560 */
3561 RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx);
3562 RCU_INIT_POINTER(next->perf_event_ctxp, ctx);
3563
3564 do_switch = 0;
3565
3566 perf_event_sync_stat(ctx, next_ctx);
3567 }
3568 raw_spin_unlock(&next_ctx->lock);
3569 raw_spin_unlock(&ctx->lock);
3570 }
3571 unlock:
3572 rcu_read_unlock();
3573
3574 if (do_switch) {
3575 raw_spin_lock(&ctx->lock);
3576 perf_ctx_disable(ctx, false);
3577
3578 inside_switch:
3579 perf_ctx_sched_task_cb(ctx, false);
3580 task_ctx_sched_out(ctx, EVENT_ALL);
3581
3582 perf_ctx_enable(ctx, false);
3583 raw_spin_unlock(&ctx->lock);
3584 }
3585 }
3586
3587 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3588 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
3589
perf_sched_cb_dec(struct pmu * pmu)3590 void perf_sched_cb_dec(struct pmu *pmu)
3591 {
3592 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3593
3594 this_cpu_dec(perf_sched_cb_usages);
3595 barrier();
3596
3597 if (!--cpc->sched_cb_usage)
3598 list_del(&cpc->sched_cb_entry);
3599 }
3600
3601
perf_sched_cb_inc(struct pmu * pmu)3602 void perf_sched_cb_inc(struct pmu *pmu)
3603 {
3604 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3605
3606 if (!cpc->sched_cb_usage++)
3607 list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3608
3609 barrier();
3610 this_cpu_inc(perf_sched_cb_usages);
3611 }
3612
3613 /*
3614 * This function provides the context switch callback to the lower code
3615 * layer. It is invoked ONLY when the context switch callback is enabled.
3616 *
3617 * This callback is relevant even to per-cpu events; for example multi event
3618 * PEBS requires this to provide PID/TID information. This requires we flush
3619 * all queued PEBS records before we context switch to a new task.
3620 */
__perf_pmu_sched_task(struct perf_cpu_pmu_context * cpc,bool sched_in)3621 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in)
3622 {
3623 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3624 struct pmu *pmu;
3625
3626 pmu = cpc->epc.pmu;
3627
3628 /* software PMUs will not have sched_task */
3629 if (WARN_ON_ONCE(!pmu->sched_task))
3630 return;
3631
3632 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3633 perf_pmu_disable(pmu);
3634
3635 pmu->sched_task(cpc->task_epc, sched_in);
3636
3637 perf_pmu_enable(pmu);
3638 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3639 }
3640
perf_pmu_sched_task(struct task_struct * prev,struct task_struct * next,bool sched_in)3641 static void perf_pmu_sched_task(struct task_struct *prev,
3642 struct task_struct *next,
3643 bool sched_in)
3644 {
3645 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3646 struct perf_cpu_pmu_context *cpc;
3647
3648 /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */
3649 if (prev == next || cpuctx->task_ctx)
3650 return;
3651
3652 list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry)
3653 __perf_pmu_sched_task(cpc, sched_in);
3654 }
3655
3656 static void perf_event_switch(struct task_struct *task,
3657 struct task_struct *next_prev, bool sched_in);
3658
3659 /*
3660 * Called from scheduler to remove the events of the current task,
3661 * with interrupts disabled.
3662 *
3663 * We stop each event and update the event value in event->count.
3664 *
3665 * This does not protect us against NMI, but disable()
3666 * sets the disabled bit in the control field of event _before_
3667 * accessing the event control register. If a NMI hits, then it will
3668 * not restart the event.
3669 */
__perf_event_task_sched_out(struct task_struct * task,struct task_struct * next)3670 void __perf_event_task_sched_out(struct task_struct *task,
3671 struct task_struct *next)
3672 {
3673 if (__this_cpu_read(perf_sched_cb_usages))
3674 perf_pmu_sched_task(task, next, false);
3675
3676 if (atomic_read(&nr_switch_events))
3677 perf_event_switch(task, next, false);
3678
3679 perf_event_context_sched_out(task, next);
3680
3681 /*
3682 * if cgroup events exist on this CPU, then we need
3683 * to check if we have to switch out PMU state.
3684 * cgroup event are system-wide mode only
3685 */
3686 perf_cgroup_switch(next);
3687 }
3688
perf_less_group_idx(const void * l,const void * r)3689 static bool perf_less_group_idx(const void *l, const void *r)
3690 {
3691 const struct perf_event *le = *(const struct perf_event **)l;
3692 const struct perf_event *re = *(const struct perf_event **)r;
3693
3694 return le->group_index < re->group_index;
3695 }
3696
swap_ptr(void * l,void * r)3697 static void swap_ptr(void *l, void *r)
3698 {
3699 void **lp = l, **rp = r;
3700
3701 swap(*lp, *rp);
3702 }
3703
3704 static const struct min_heap_callbacks perf_min_heap = {
3705 .elem_size = sizeof(struct perf_event *),
3706 .less = perf_less_group_idx,
3707 .swp = swap_ptr,
3708 };
3709
__heap_add(struct min_heap * heap,struct perf_event * event)3710 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3711 {
3712 struct perf_event **itrs = heap->data;
3713
3714 if (event) {
3715 itrs[heap->nr] = event;
3716 heap->nr++;
3717 }
3718 }
3719
__link_epc(struct perf_event_pmu_context * pmu_ctx)3720 static void __link_epc(struct perf_event_pmu_context *pmu_ctx)
3721 {
3722 struct perf_cpu_pmu_context *cpc;
3723
3724 if (!pmu_ctx->ctx->task)
3725 return;
3726
3727 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3728 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3729 cpc->task_epc = pmu_ctx;
3730 }
3731
visit_groups_merge(struct perf_event_context * ctx,struct perf_event_groups * groups,int cpu,struct pmu * pmu,int (* func)(struct perf_event *,void *),void * data)3732 static noinline int visit_groups_merge(struct perf_event_context *ctx,
3733 struct perf_event_groups *groups, int cpu,
3734 struct pmu *pmu,
3735 int (*func)(struct perf_event *, void *),
3736 void *data)
3737 {
3738 #ifdef CONFIG_CGROUP_PERF
3739 struct cgroup_subsys_state *css = NULL;
3740 #endif
3741 struct perf_cpu_context *cpuctx = NULL;
3742 /* Space for per CPU and/or any CPU event iterators. */
3743 struct perf_event *itrs[2];
3744 struct min_heap event_heap;
3745 struct perf_event **evt;
3746 int ret;
3747
3748 if (pmu->filter && pmu->filter(pmu, cpu))
3749 return 0;
3750
3751 if (!ctx->task) {
3752 cpuctx = this_cpu_ptr(&perf_cpu_context);
3753 event_heap = (struct min_heap){
3754 .data = cpuctx->heap,
3755 .nr = 0,
3756 .size = cpuctx->heap_size,
3757 };
3758
3759 lockdep_assert_held(&cpuctx->ctx.lock);
3760
3761 #ifdef CONFIG_CGROUP_PERF
3762 if (cpuctx->cgrp)
3763 css = &cpuctx->cgrp->css;
3764 #endif
3765 } else {
3766 event_heap = (struct min_heap){
3767 .data = itrs,
3768 .nr = 0,
3769 .size = ARRAY_SIZE(itrs),
3770 };
3771 /* Events not within a CPU context may be on any CPU. */
3772 __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL));
3773 }
3774 evt = event_heap.data;
3775
3776 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL));
3777
3778 #ifdef CONFIG_CGROUP_PERF
3779 for (; css; css = css->parent)
3780 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup));
3781 #endif
3782
3783 if (event_heap.nr) {
3784 __link_epc((*evt)->pmu_ctx);
3785 perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
3786 }
3787
3788 min_heapify_all(&event_heap, &perf_min_heap);
3789
3790 while (event_heap.nr) {
3791 ret = func(*evt, data);
3792 if (ret)
3793 return ret;
3794
3795 *evt = perf_event_groups_next(*evt, pmu);
3796 if (*evt)
3797 min_heapify(&event_heap, 0, &perf_min_heap);
3798 else
3799 min_heap_pop(&event_heap, &perf_min_heap);
3800 }
3801
3802 return 0;
3803 }
3804
3805 /*
3806 * Because the userpage is strictly per-event (there is no concept of context,
3807 * so there cannot be a context indirection), every userpage must be updated
3808 * when context time starts :-(
3809 *
3810 * IOW, we must not miss EVENT_TIME edges.
3811 */
event_update_userpage(struct perf_event * event)3812 static inline bool event_update_userpage(struct perf_event *event)
3813 {
3814 if (likely(!atomic_read(&event->mmap_count)))
3815 return false;
3816
3817 perf_event_update_time(event);
3818 perf_event_update_userpage(event);
3819
3820 return true;
3821 }
3822
group_update_userpage(struct perf_event * group_event)3823 static inline void group_update_userpage(struct perf_event *group_event)
3824 {
3825 struct perf_event *event;
3826
3827 if (!event_update_userpage(group_event))
3828 return;
3829
3830 for_each_sibling_event(event, group_event)
3831 event_update_userpage(event);
3832 }
3833
merge_sched_in(struct perf_event * event,void * data)3834 static int merge_sched_in(struct perf_event *event, void *data)
3835 {
3836 struct perf_event_context *ctx = event->ctx;
3837 int *can_add_hw = data;
3838
3839 if (event->state <= PERF_EVENT_STATE_OFF)
3840 return 0;
3841
3842 if (!event_filter_match(event))
3843 return 0;
3844
3845 if (group_can_go_on(event, *can_add_hw)) {
3846 if (!group_sched_in(event, ctx))
3847 list_add_tail(&event->active_list, get_event_list(event));
3848 }
3849
3850 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3851 *can_add_hw = 0;
3852 if (event->attr.pinned) {
3853 perf_cgroup_event_disable(event, ctx);
3854 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3855 } else {
3856 struct perf_cpu_pmu_context *cpc;
3857
3858 event->pmu_ctx->rotate_necessary = 1;
3859 cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context);
3860 perf_mux_hrtimer_restart(cpc);
3861 group_update_userpage(event);
3862 }
3863 }
3864
3865 return 0;
3866 }
3867
pmu_groups_sched_in(struct perf_event_context * ctx,struct perf_event_groups * groups,struct pmu * pmu)3868 static void pmu_groups_sched_in(struct perf_event_context *ctx,
3869 struct perf_event_groups *groups,
3870 struct pmu *pmu)
3871 {
3872 int can_add_hw = 1;
3873 visit_groups_merge(ctx, groups, smp_processor_id(), pmu,
3874 merge_sched_in, &can_add_hw);
3875 }
3876
ctx_groups_sched_in(struct perf_event_context * ctx,struct perf_event_groups * groups,bool cgroup)3877 static void ctx_groups_sched_in(struct perf_event_context *ctx,
3878 struct perf_event_groups *groups,
3879 bool cgroup)
3880 {
3881 struct perf_event_pmu_context *pmu_ctx;
3882
3883 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3884 if (cgroup && !pmu_ctx->nr_cgroups)
3885 continue;
3886 pmu_groups_sched_in(ctx, groups, pmu_ctx->pmu);
3887 }
3888 }
3889
__pmu_ctx_sched_in(struct perf_event_context * ctx,struct pmu * pmu)3890 static void __pmu_ctx_sched_in(struct perf_event_context *ctx,
3891 struct pmu *pmu)
3892 {
3893 pmu_groups_sched_in(ctx, &ctx->flexible_groups, pmu);
3894 }
3895
3896 static void
ctx_sched_in(struct perf_event_context * ctx,enum event_type_t event_type)3897 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
3898 {
3899 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3900 int is_active = ctx->is_active;
3901 bool cgroup = event_type & EVENT_CGROUP;
3902
3903 event_type &= ~EVENT_CGROUP;
3904
3905 lockdep_assert_held(&ctx->lock);
3906
3907 if (likely(!ctx->nr_events))
3908 return;
3909
3910 if (!(is_active & EVENT_TIME)) {
3911 /* start ctx time */
3912 __update_context_time(ctx, false);
3913 perf_cgroup_set_timestamp(cpuctx);
3914 /*
3915 * CPU-release for the below ->is_active store,
3916 * see __load_acquire() in perf_event_time_now()
3917 */
3918 barrier();
3919 }
3920
3921 ctx->is_active |= (event_type | EVENT_TIME);
3922 if (ctx->task) {
3923 if (!is_active)
3924 cpuctx->task_ctx = ctx;
3925 else
3926 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3927 }
3928
3929 is_active ^= ctx->is_active; /* changed bits */
3930
3931 /*
3932 * First go through the list and put on any pinned groups
3933 * in order to give them the best chance of going on.
3934 */
3935 if (is_active & EVENT_PINNED)
3936 ctx_groups_sched_in(ctx, &ctx->pinned_groups, cgroup);
3937
3938 /* Then walk through the lower prio flexible groups */
3939 if (is_active & EVENT_FLEXIBLE)
3940 ctx_groups_sched_in(ctx, &ctx->flexible_groups, cgroup);
3941 }
3942
perf_event_context_sched_in(struct task_struct * task)3943 static void perf_event_context_sched_in(struct task_struct *task)
3944 {
3945 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3946 struct perf_event_context *ctx;
3947
3948 rcu_read_lock();
3949 ctx = rcu_dereference(task->perf_event_ctxp);
3950 if (!ctx)
3951 goto rcu_unlock;
3952
3953 if (cpuctx->task_ctx == ctx) {
3954 perf_ctx_lock(cpuctx, ctx);
3955 perf_ctx_disable(ctx, false);
3956
3957 perf_ctx_sched_task_cb(ctx, true);
3958
3959 perf_ctx_enable(ctx, false);
3960 perf_ctx_unlock(cpuctx, ctx);
3961 goto rcu_unlock;
3962 }
3963
3964 perf_ctx_lock(cpuctx, ctx);
3965 /*
3966 * We must check ctx->nr_events while holding ctx->lock, such
3967 * that we serialize against perf_install_in_context().
3968 */
3969 if (!ctx->nr_events)
3970 goto unlock;
3971
3972 perf_ctx_disable(ctx, false);
3973 /*
3974 * We want to keep the following priority order:
3975 * cpu pinned (that don't need to move), task pinned,
3976 * cpu flexible, task flexible.
3977 *
3978 * However, if task's ctx is not carrying any pinned
3979 * events, no need to flip the cpuctx's events around.
3980 */
3981 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) {
3982 perf_ctx_disable(&cpuctx->ctx, false);
3983 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
3984 }
3985
3986 perf_event_sched_in(cpuctx, ctx);
3987
3988 perf_ctx_sched_task_cb(cpuctx->task_ctx, true);
3989
3990 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3991 perf_ctx_enable(&cpuctx->ctx, false);
3992
3993 perf_ctx_enable(ctx, false);
3994
3995 unlock:
3996 perf_ctx_unlock(cpuctx, ctx);
3997 rcu_unlock:
3998 rcu_read_unlock();
3999 }
4000
4001 /*
4002 * Called from scheduler to add the events of the current task
4003 * with interrupts disabled.
4004 *
4005 * We restore the event value and then enable it.
4006 *
4007 * This does not protect us against NMI, but enable()
4008 * sets the enabled bit in the control field of event _before_
4009 * accessing the event control register. If a NMI hits, then it will
4010 * keep the event running.
4011 */
__perf_event_task_sched_in(struct task_struct * prev,struct task_struct * task)4012 void __perf_event_task_sched_in(struct task_struct *prev,
4013 struct task_struct *task)
4014 {
4015 perf_event_context_sched_in(task);
4016
4017 if (atomic_read(&nr_switch_events))
4018 perf_event_switch(task, prev, true);
4019
4020 if (__this_cpu_read(perf_sched_cb_usages))
4021 perf_pmu_sched_task(prev, task, true);
4022 }
4023
perf_calculate_period(struct perf_event * event,u64 nsec,u64 count)4024 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
4025 {
4026 u64 frequency = event->attr.sample_freq;
4027 u64 sec = NSEC_PER_SEC;
4028 u64 divisor, dividend;
4029
4030 int count_fls, nsec_fls, frequency_fls, sec_fls;
4031
4032 count_fls = fls64(count);
4033 nsec_fls = fls64(nsec);
4034 frequency_fls = fls64(frequency);
4035 sec_fls = 30;
4036
4037 /*
4038 * We got @count in @nsec, with a target of sample_freq HZ
4039 * the target period becomes:
4040 *
4041 * @count * 10^9
4042 * period = -------------------
4043 * @nsec * sample_freq
4044 *
4045 */
4046
4047 /*
4048 * Reduce accuracy by one bit such that @a and @b converge
4049 * to a similar magnitude.
4050 */
4051 #define REDUCE_FLS(a, b) \
4052 do { \
4053 if (a##_fls > b##_fls) { \
4054 a >>= 1; \
4055 a##_fls--; \
4056 } else { \
4057 b >>= 1; \
4058 b##_fls--; \
4059 } \
4060 } while (0)
4061
4062 /*
4063 * Reduce accuracy until either term fits in a u64, then proceed with
4064 * the other, so that finally we can do a u64/u64 division.
4065 */
4066 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4067 REDUCE_FLS(nsec, frequency);
4068 REDUCE_FLS(sec, count);
4069 }
4070
4071 if (count_fls + sec_fls > 64) {
4072 divisor = nsec * frequency;
4073
4074 while (count_fls + sec_fls > 64) {
4075 REDUCE_FLS(count, sec);
4076 divisor >>= 1;
4077 }
4078
4079 dividend = count * sec;
4080 } else {
4081 dividend = count * sec;
4082
4083 while (nsec_fls + frequency_fls > 64) {
4084 REDUCE_FLS(nsec, frequency);
4085 dividend >>= 1;
4086 }
4087
4088 divisor = nsec * frequency;
4089 }
4090
4091 if (!divisor)
4092 return dividend;
4093
4094 return div64_u64(dividend, divisor);
4095 }
4096
4097 static DEFINE_PER_CPU(int, perf_throttled_count);
4098 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4099
perf_adjust_period(struct perf_event * event,u64 nsec,u64 count,bool disable)4100 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4101 {
4102 struct hw_perf_event *hwc = &event->hw;
4103 s64 period, sample_period;
4104 s64 delta;
4105
4106 period = perf_calculate_period(event, nsec, count);
4107
4108 delta = (s64)(period - hwc->sample_period);
4109 delta = (delta + 7) / 8; /* low pass filter */
4110
4111 sample_period = hwc->sample_period + delta;
4112
4113 if (!sample_period)
4114 sample_period = 1;
4115
4116 hwc->sample_period = sample_period;
4117
4118 if (local64_read(&hwc->period_left) > 8*sample_period) {
4119 if (disable)
4120 event->pmu->stop(event, PERF_EF_UPDATE);
4121
4122 local64_set(&hwc->period_left, 0);
4123
4124 if (disable)
4125 event->pmu->start(event, PERF_EF_RELOAD);
4126 }
4127 }
4128
perf_adjust_freq_unthr_events(struct list_head * event_list)4129 static void perf_adjust_freq_unthr_events(struct list_head *event_list)
4130 {
4131 struct perf_event *event;
4132 struct hw_perf_event *hwc;
4133 u64 now, period = TICK_NSEC;
4134 s64 delta;
4135
4136 list_for_each_entry(event, event_list, active_list) {
4137 if (event->state != PERF_EVENT_STATE_ACTIVE)
4138 continue;
4139
4140 // XXX use visit thingy to avoid the -1,cpu match
4141 if (!event_filter_match(event))
4142 continue;
4143
4144 hwc = &event->hw;
4145
4146 if (hwc->interrupts == MAX_INTERRUPTS) {
4147 hwc->interrupts = 0;
4148 perf_log_throttle(event, 1);
4149 if (!event->attr.freq || !event->attr.sample_freq)
4150 event->pmu->start(event, 0);
4151 }
4152
4153 if (!event->attr.freq || !event->attr.sample_freq)
4154 continue;
4155
4156 /*
4157 * stop the event and update event->count
4158 */
4159 event->pmu->stop(event, PERF_EF_UPDATE);
4160
4161 now = local64_read(&event->count);
4162 delta = now - hwc->freq_count_stamp;
4163 hwc->freq_count_stamp = now;
4164
4165 /*
4166 * restart the event
4167 * reload only if value has changed
4168 * we have stopped the event so tell that
4169 * to perf_adjust_period() to avoid stopping it
4170 * twice.
4171 */
4172 if (delta > 0)
4173 perf_adjust_period(event, period, delta, false);
4174
4175 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4176 }
4177 }
4178
4179 /*
4180 * combine freq adjustment with unthrottling to avoid two passes over the
4181 * events. At the same time, make sure, having freq events does not change
4182 * the rate of unthrottling as that would introduce bias.
4183 */
4184 static void
perf_adjust_freq_unthr_context(struct perf_event_context * ctx,bool unthrottle)4185 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle)
4186 {
4187 struct perf_event_pmu_context *pmu_ctx;
4188
4189 /*
4190 * only need to iterate over all events iff:
4191 * - context have events in frequency mode (needs freq adjust)
4192 * - there are events to unthrottle on this cpu
4193 */
4194 if (!(ctx->nr_freq || unthrottle))
4195 return;
4196
4197 raw_spin_lock(&ctx->lock);
4198
4199 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4200 if (!(pmu_ctx->nr_freq || unthrottle))
4201 continue;
4202 if (!perf_pmu_ctx_is_active(pmu_ctx))
4203 continue;
4204 if (pmu_ctx->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT)
4205 continue;
4206
4207 perf_pmu_disable(pmu_ctx->pmu);
4208 perf_adjust_freq_unthr_events(&pmu_ctx->pinned_active);
4209 perf_adjust_freq_unthr_events(&pmu_ctx->flexible_active);
4210 perf_pmu_enable(pmu_ctx->pmu);
4211 }
4212
4213 raw_spin_unlock(&ctx->lock);
4214 }
4215
4216 /*
4217 * Move @event to the tail of the @ctx's elegible events.
4218 */
rotate_ctx(struct perf_event_context * ctx,struct perf_event * event)4219 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4220 {
4221 /*
4222 * Rotate the first entry last of non-pinned groups. Rotation might be
4223 * disabled by the inheritance code.
4224 */
4225 if (ctx->rotate_disable)
4226 return;
4227
4228 perf_event_groups_delete(&ctx->flexible_groups, event);
4229 perf_event_groups_insert(&ctx->flexible_groups, event);
4230 }
4231
4232 /* pick an event from the flexible_groups to rotate */
4233 static inline struct perf_event *
ctx_event_to_rotate(struct perf_event_pmu_context * pmu_ctx)4234 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx)
4235 {
4236 struct perf_event *event;
4237 struct rb_node *node;
4238 struct rb_root *tree;
4239 struct __group_key key = {
4240 .pmu = pmu_ctx->pmu,
4241 };
4242
4243 /* pick the first active flexible event */
4244 event = list_first_entry_or_null(&pmu_ctx->flexible_active,
4245 struct perf_event, active_list);
4246 if (event)
4247 goto out;
4248
4249 /* if no active flexible event, pick the first event */
4250 tree = &pmu_ctx->ctx->flexible_groups.tree;
4251
4252 if (!pmu_ctx->ctx->task) {
4253 key.cpu = smp_processor_id();
4254
4255 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4256 if (node)
4257 event = __node_2_pe(node);
4258 goto out;
4259 }
4260
4261 key.cpu = -1;
4262 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4263 if (node) {
4264 event = __node_2_pe(node);
4265 goto out;
4266 }
4267
4268 key.cpu = smp_processor_id();
4269 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4270 if (node)
4271 event = __node_2_pe(node);
4272
4273 out:
4274 /*
4275 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4276 * finds there are unschedulable events, it will set it again.
4277 */
4278 pmu_ctx->rotate_necessary = 0;
4279
4280 return event;
4281 }
4282
perf_rotate_context(struct perf_cpu_pmu_context * cpc)4283 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc)
4284 {
4285 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4286 struct perf_event_pmu_context *cpu_epc, *task_epc = NULL;
4287 struct perf_event *cpu_event = NULL, *task_event = NULL;
4288 int cpu_rotate, task_rotate;
4289 struct pmu *pmu;
4290
4291 /*
4292 * Since we run this from IRQ context, nobody can install new
4293 * events, thus the event count values are stable.
4294 */
4295
4296 cpu_epc = &cpc->epc;
4297 pmu = cpu_epc->pmu;
4298 task_epc = cpc->task_epc;
4299
4300 cpu_rotate = cpu_epc->rotate_necessary;
4301 task_rotate = task_epc ? task_epc->rotate_necessary : 0;
4302
4303 if (!(cpu_rotate || task_rotate))
4304 return false;
4305
4306 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4307 perf_pmu_disable(pmu);
4308
4309 if (task_rotate)
4310 task_event = ctx_event_to_rotate(task_epc);
4311 if (cpu_rotate)
4312 cpu_event = ctx_event_to_rotate(cpu_epc);
4313
4314 /*
4315 * As per the order given at ctx_resched() first 'pop' task flexible
4316 * and then, if needed CPU flexible.
4317 */
4318 if (task_event || (task_epc && cpu_event)) {
4319 update_context_time(task_epc->ctx);
4320 __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE);
4321 }
4322
4323 if (cpu_event) {
4324 update_context_time(&cpuctx->ctx);
4325 __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE);
4326 rotate_ctx(&cpuctx->ctx, cpu_event);
4327 __pmu_ctx_sched_in(&cpuctx->ctx, pmu);
4328 }
4329
4330 if (task_event)
4331 rotate_ctx(task_epc->ctx, task_event);
4332
4333 if (task_event || (task_epc && cpu_event))
4334 __pmu_ctx_sched_in(task_epc->ctx, pmu);
4335
4336 perf_pmu_enable(pmu);
4337 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4338
4339 return true;
4340 }
4341
perf_event_task_tick(void)4342 void perf_event_task_tick(void)
4343 {
4344 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4345 struct perf_event_context *ctx;
4346 int throttled;
4347
4348 lockdep_assert_irqs_disabled();
4349
4350 __this_cpu_inc(perf_throttled_seq);
4351 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4352 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4353
4354 perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled);
4355
4356 rcu_read_lock();
4357 ctx = rcu_dereference(current->perf_event_ctxp);
4358 if (ctx)
4359 perf_adjust_freq_unthr_context(ctx, !!throttled);
4360 rcu_read_unlock();
4361 }
4362
event_enable_on_exec(struct perf_event * event,struct perf_event_context * ctx)4363 static int event_enable_on_exec(struct perf_event *event,
4364 struct perf_event_context *ctx)
4365 {
4366 if (!event->attr.enable_on_exec)
4367 return 0;
4368
4369 event->attr.enable_on_exec = 0;
4370 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4371 return 0;
4372
4373 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4374
4375 return 1;
4376 }
4377
4378 /*
4379 * Enable all of a task's events that have been marked enable-on-exec.
4380 * This expects task == current.
4381 */
perf_event_enable_on_exec(struct perf_event_context * ctx)4382 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
4383 {
4384 struct perf_event_context *clone_ctx = NULL;
4385 enum event_type_t event_type = 0;
4386 struct perf_cpu_context *cpuctx;
4387 struct perf_event *event;
4388 unsigned long flags;
4389 int enabled = 0;
4390
4391 local_irq_save(flags);
4392 if (WARN_ON_ONCE(current->perf_event_ctxp != ctx))
4393 goto out;
4394
4395 if (!ctx->nr_events)
4396 goto out;
4397
4398 cpuctx = this_cpu_ptr(&perf_cpu_context);
4399 perf_ctx_lock(cpuctx, ctx);
4400 ctx_sched_out(ctx, EVENT_TIME);
4401
4402 list_for_each_entry(event, &ctx->event_list, event_entry) {
4403 enabled |= event_enable_on_exec(event, ctx);
4404 event_type |= get_event_type(event);
4405 }
4406
4407 /*
4408 * Unclone and reschedule this context if we enabled any event.
4409 */
4410 if (enabled) {
4411 clone_ctx = unclone_ctx(ctx);
4412 ctx_resched(cpuctx, ctx, event_type);
4413 } else {
4414 ctx_sched_in(ctx, EVENT_TIME);
4415 }
4416 perf_ctx_unlock(cpuctx, ctx);
4417
4418 out:
4419 local_irq_restore(flags);
4420
4421 if (clone_ctx)
4422 put_ctx(clone_ctx);
4423 }
4424
4425 static void perf_remove_from_owner(struct perf_event *event);
4426 static void perf_event_exit_event(struct perf_event *event,
4427 struct perf_event_context *ctx);
4428
4429 /*
4430 * Removes all events from the current task that have been marked
4431 * remove-on-exec, and feeds their values back to parent events.
4432 */
perf_event_remove_on_exec(struct perf_event_context * ctx)4433 static void perf_event_remove_on_exec(struct perf_event_context *ctx)
4434 {
4435 struct perf_event_context *clone_ctx = NULL;
4436 struct perf_event *event, *next;
4437 unsigned long flags;
4438 bool modified = false;
4439
4440 mutex_lock(&ctx->mutex);
4441
4442 if (WARN_ON_ONCE(ctx->task != current))
4443 goto unlock;
4444
4445 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4446 if (!event->attr.remove_on_exec)
4447 continue;
4448
4449 if (!is_kernel_event(event))
4450 perf_remove_from_owner(event);
4451
4452 modified = true;
4453
4454 perf_event_exit_event(event, ctx);
4455 }
4456
4457 raw_spin_lock_irqsave(&ctx->lock, flags);
4458 if (modified)
4459 clone_ctx = unclone_ctx(ctx);
4460 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4461
4462 unlock:
4463 mutex_unlock(&ctx->mutex);
4464
4465 if (clone_ctx)
4466 put_ctx(clone_ctx);
4467 }
4468
4469 struct perf_read_data {
4470 struct perf_event *event;
4471 bool group;
4472 int ret;
4473 };
4474
__perf_event_read_cpu(struct perf_event * event,int event_cpu)4475 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4476 {
4477 u16 local_pkg, event_pkg;
4478
4479 if ((unsigned)event_cpu >= nr_cpu_ids)
4480 return event_cpu;
4481
4482 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4483 int local_cpu = smp_processor_id();
4484
4485 event_pkg = topology_physical_package_id(event_cpu);
4486 local_pkg = topology_physical_package_id(local_cpu);
4487
4488 if (event_pkg == local_pkg)
4489 return local_cpu;
4490 }
4491
4492 return event_cpu;
4493 }
4494
4495 /*
4496 * Cross CPU call to read the hardware event
4497 */
__perf_event_read(void * info)4498 static void __perf_event_read(void *info)
4499 {
4500 struct perf_read_data *data = info;
4501 struct perf_event *sub, *event = data->event;
4502 struct perf_event_context *ctx = event->ctx;
4503 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4504 struct pmu *pmu = event->pmu;
4505
4506 /*
4507 * If this is a task context, we need to check whether it is
4508 * the current task context of this cpu. If not it has been
4509 * scheduled out before the smp call arrived. In that case
4510 * event->count would have been updated to a recent sample
4511 * when the event was scheduled out.
4512 */
4513 if (ctx->task && cpuctx->task_ctx != ctx)
4514 return;
4515
4516 raw_spin_lock(&ctx->lock);
4517 if (ctx->is_active & EVENT_TIME) {
4518 update_context_time(ctx);
4519 update_cgrp_time_from_event(event);
4520 }
4521
4522 perf_event_update_time(event);
4523 if (data->group)
4524 perf_event_update_sibling_time(event);
4525
4526 if (event->state != PERF_EVENT_STATE_ACTIVE)
4527 goto unlock;
4528
4529 if (!data->group) {
4530 pmu->read(event);
4531 data->ret = 0;
4532 goto unlock;
4533 }
4534
4535 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4536
4537 pmu->read(event);
4538
4539 for_each_sibling_event(sub, event) {
4540 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4541 /*
4542 * Use sibling's PMU rather than @event's since
4543 * sibling could be on different (eg: software) PMU.
4544 */
4545 sub->pmu->read(sub);
4546 }
4547 }
4548
4549 data->ret = pmu->commit_txn(pmu);
4550
4551 unlock:
4552 raw_spin_unlock(&ctx->lock);
4553 }
4554
perf_event_count(struct perf_event * event)4555 static inline u64 perf_event_count(struct perf_event *event)
4556 {
4557 return local64_read(&event->count) + atomic64_read(&event->child_count);
4558 }
4559
calc_timer_values(struct perf_event * event,u64 * now,u64 * enabled,u64 * running)4560 static void calc_timer_values(struct perf_event *event,
4561 u64 *now,
4562 u64 *enabled,
4563 u64 *running)
4564 {
4565 u64 ctx_time;
4566
4567 *now = perf_clock();
4568 ctx_time = perf_event_time_now(event, *now);
4569 __perf_update_times(event, ctx_time, enabled, running);
4570 }
4571
4572 /*
4573 * NMI-safe method to read a local event, that is an event that
4574 * is:
4575 * - either for the current task, or for this CPU
4576 * - does not have inherit set, for inherited task events
4577 * will not be local and we cannot read them atomically
4578 * - must not have a pmu::count method
4579 */
perf_event_read_local(struct perf_event * event,u64 * value,u64 * enabled,u64 * running)4580 int perf_event_read_local(struct perf_event *event, u64 *value,
4581 u64 *enabled, u64 *running)
4582 {
4583 unsigned long flags;
4584 int event_oncpu;
4585 int event_cpu;
4586 int ret = 0;
4587
4588 /*
4589 * Disabling interrupts avoids all counter scheduling (context
4590 * switches, timer based rotation and IPIs).
4591 */
4592 local_irq_save(flags);
4593
4594 /*
4595 * It must not be an event with inherit set, we cannot read
4596 * all child counters from atomic context.
4597 */
4598 if (event->attr.inherit) {
4599 ret = -EOPNOTSUPP;
4600 goto out;
4601 }
4602
4603 /* If this is a per-task event, it must be for current */
4604 if ((event->attach_state & PERF_ATTACH_TASK) &&
4605 event->hw.target != current) {
4606 ret = -EINVAL;
4607 goto out;
4608 }
4609
4610 /*
4611 * Get the event CPU numbers, and adjust them to local if the event is
4612 * a per-package event that can be read locally
4613 */
4614 event_oncpu = __perf_event_read_cpu(event, event->oncpu);
4615 event_cpu = __perf_event_read_cpu(event, event->cpu);
4616
4617 /* If this is a per-CPU event, it must be for this CPU */
4618 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4619 event_cpu != smp_processor_id()) {
4620 ret = -EINVAL;
4621 goto out;
4622 }
4623
4624 /* If this is a pinned event it must be running on this CPU */
4625 if (event->attr.pinned && event_oncpu != smp_processor_id()) {
4626 ret = -EBUSY;
4627 goto out;
4628 }
4629
4630 /*
4631 * If the event is currently on this CPU, its either a per-task event,
4632 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4633 * oncpu == -1).
4634 */
4635 if (event_oncpu == smp_processor_id())
4636 event->pmu->read(event);
4637
4638 *value = local64_read(&event->count);
4639 if (enabled || running) {
4640 u64 __enabled, __running, __now;
4641
4642 calc_timer_values(event, &__now, &__enabled, &__running);
4643 if (enabled)
4644 *enabled = __enabled;
4645 if (running)
4646 *running = __running;
4647 }
4648 out:
4649 local_irq_restore(flags);
4650
4651 return ret;
4652 }
4653
perf_event_read(struct perf_event * event,bool group)4654 static int perf_event_read(struct perf_event *event, bool group)
4655 {
4656 enum perf_event_state state = READ_ONCE(event->state);
4657 int event_cpu, ret = 0;
4658
4659 /*
4660 * If event is enabled and currently active on a CPU, update the
4661 * value in the event structure:
4662 */
4663 again:
4664 if (state == PERF_EVENT_STATE_ACTIVE) {
4665 struct perf_read_data data;
4666
4667 /*
4668 * Orders the ->state and ->oncpu loads such that if we see
4669 * ACTIVE we must also see the right ->oncpu.
4670 *
4671 * Matches the smp_wmb() from event_sched_in().
4672 */
4673 smp_rmb();
4674
4675 event_cpu = READ_ONCE(event->oncpu);
4676 if ((unsigned)event_cpu >= nr_cpu_ids)
4677 return 0;
4678
4679 data = (struct perf_read_data){
4680 .event = event,
4681 .group = group,
4682 .ret = 0,
4683 };
4684
4685 preempt_disable();
4686 event_cpu = __perf_event_read_cpu(event, event_cpu);
4687
4688 /*
4689 * Purposely ignore the smp_call_function_single() return
4690 * value.
4691 *
4692 * If event_cpu isn't a valid CPU it means the event got
4693 * scheduled out and that will have updated the event count.
4694 *
4695 * Therefore, either way, we'll have an up-to-date event count
4696 * after this.
4697 */
4698 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4699 preempt_enable();
4700 ret = data.ret;
4701
4702 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4703 struct perf_event_context *ctx = event->ctx;
4704 unsigned long flags;
4705
4706 raw_spin_lock_irqsave(&ctx->lock, flags);
4707 state = event->state;
4708 if (state != PERF_EVENT_STATE_INACTIVE) {
4709 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4710 goto again;
4711 }
4712
4713 /*
4714 * May read while context is not active (e.g., thread is
4715 * blocked), in that case we cannot update context time
4716 */
4717 if (ctx->is_active & EVENT_TIME) {
4718 update_context_time(ctx);
4719 update_cgrp_time_from_event(event);
4720 }
4721
4722 perf_event_update_time(event);
4723 if (group)
4724 perf_event_update_sibling_time(event);
4725 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4726 }
4727
4728 return ret;
4729 }
4730
4731 /*
4732 * Initialize the perf_event context in a task_struct:
4733 */
__perf_event_init_context(struct perf_event_context * ctx)4734 static void __perf_event_init_context(struct perf_event_context *ctx)
4735 {
4736 raw_spin_lock_init(&ctx->lock);
4737 mutex_init(&ctx->mutex);
4738 INIT_LIST_HEAD(&ctx->pmu_ctx_list);
4739 perf_event_groups_init(&ctx->pinned_groups);
4740 perf_event_groups_init(&ctx->flexible_groups);
4741 INIT_LIST_HEAD(&ctx->event_list);
4742 refcount_set(&ctx->refcount, 1);
4743 }
4744
4745 static void
__perf_init_event_pmu_context(struct perf_event_pmu_context * epc,struct pmu * pmu)4746 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu)
4747 {
4748 epc->pmu = pmu;
4749 INIT_LIST_HEAD(&epc->pmu_ctx_entry);
4750 INIT_LIST_HEAD(&epc->pinned_active);
4751 INIT_LIST_HEAD(&epc->flexible_active);
4752 atomic_set(&epc->refcount, 1);
4753 }
4754
4755 static struct perf_event_context *
alloc_perf_context(struct task_struct * task)4756 alloc_perf_context(struct task_struct *task)
4757 {
4758 struct perf_event_context *ctx;
4759
4760 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4761 if (!ctx)
4762 return NULL;
4763
4764 __perf_event_init_context(ctx);
4765 if (task)
4766 ctx->task = get_task_struct(task);
4767
4768 return ctx;
4769 }
4770
4771 static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)4772 find_lively_task_by_vpid(pid_t vpid)
4773 {
4774 struct task_struct *task;
4775
4776 rcu_read_lock();
4777 if (!vpid)
4778 task = current;
4779 else
4780 task = find_task_by_vpid(vpid);
4781 if (task)
4782 get_task_struct(task);
4783 rcu_read_unlock();
4784
4785 if (!task)
4786 return ERR_PTR(-ESRCH);
4787
4788 return task;
4789 }
4790
4791 /*
4792 * Returns a matching context with refcount and pincount.
4793 */
4794 static struct perf_event_context *
find_get_context(struct task_struct * task,struct perf_event * event)4795 find_get_context(struct task_struct *task, struct perf_event *event)
4796 {
4797 struct perf_event_context *ctx, *clone_ctx = NULL;
4798 struct perf_cpu_context *cpuctx;
4799 unsigned long flags;
4800 int err;
4801
4802 if (!task) {
4803 /* Must be root to operate on a CPU event: */
4804 err = perf_allow_cpu(&event->attr);
4805 if (err)
4806 return ERR_PTR(err);
4807
4808 cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
4809 ctx = &cpuctx->ctx;
4810 get_ctx(ctx);
4811 raw_spin_lock_irqsave(&ctx->lock, flags);
4812 ++ctx->pin_count;
4813 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4814
4815 return ctx;
4816 }
4817
4818 err = -EINVAL;
4819 retry:
4820 ctx = perf_lock_task_context(task, &flags);
4821 if (ctx) {
4822 clone_ctx = unclone_ctx(ctx);
4823 ++ctx->pin_count;
4824
4825 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4826
4827 if (clone_ctx)
4828 put_ctx(clone_ctx);
4829 } else {
4830 ctx = alloc_perf_context(task);
4831 err = -ENOMEM;
4832 if (!ctx)
4833 goto errout;
4834
4835 err = 0;
4836 mutex_lock(&task->perf_event_mutex);
4837 /*
4838 * If it has already passed perf_event_exit_task().
4839 * we must see PF_EXITING, it takes this mutex too.
4840 */
4841 if (task->flags & PF_EXITING)
4842 err = -ESRCH;
4843 else if (task->perf_event_ctxp)
4844 err = -EAGAIN;
4845 else {
4846 get_ctx(ctx);
4847 ++ctx->pin_count;
4848 rcu_assign_pointer(task->perf_event_ctxp, ctx);
4849 }
4850 mutex_unlock(&task->perf_event_mutex);
4851
4852 if (unlikely(err)) {
4853 put_ctx(ctx);
4854
4855 if (err == -EAGAIN)
4856 goto retry;
4857 goto errout;
4858 }
4859 }
4860
4861 return ctx;
4862
4863 errout:
4864 return ERR_PTR(err);
4865 }
4866
4867 static struct perf_event_pmu_context *
find_get_pmu_context(struct pmu * pmu,struct perf_event_context * ctx,struct perf_event * event)4868 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx,
4869 struct perf_event *event)
4870 {
4871 struct perf_event_pmu_context *new = NULL, *epc;
4872 void *task_ctx_data = NULL;
4873
4874 if (!ctx->task) {
4875 /*
4876 * perf_pmu_migrate_context() / __perf_pmu_install_event()
4877 * relies on the fact that find_get_pmu_context() cannot fail
4878 * for CPU contexts.
4879 */
4880 struct perf_cpu_pmu_context *cpc;
4881
4882 cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu);
4883 epc = &cpc->epc;
4884 raw_spin_lock_irq(&ctx->lock);
4885 if (!epc->ctx) {
4886 atomic_set(&epc->refcount, 1);
4887 epc->embedded = 1;
4888 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4889 epc->ctx = ctx;
4890 } else {
4891 WARN_ON_ONCE(epc->ctx != ctx);
4892 atomic_inc(&epc->refcount);
4893 }
4894 raw_spin_unlock_irq(&ctx->lock);
4895 return epc;
4896 }
4897
4898 new = kzalloc(sizeof(*epc), GFP_KERNEL);
4899 if (!new)
4900 return ERR_PTR(-ENOMEM);
4901
4902 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4903 task_ctx_data = alloc_task_ctx_data(pmu);
4904 if (!task_ctx_data) {
4905 kfree(new);
4906 return ERR_PTR(-ENOMEM);
4907 }
4908 }
4909
4910 __perf_init_event_pmu_context(new, pmu);
4911
4912 /*
4913 * XXX
4914 *
4915 * lockdep_assert_held(&ctx->mutex);
4916 *
4917 * can't because perf_event_init_task() doesn't actually hold the
4918 * child_ctx->mutex.
4919 */
4920
4921 raw_spin_lock_irq(&ctx->lock);
4922 list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4923 if (epc->pmu == pmu) {
4924 WARN_ON_ONCE(epc->ctx != ctx);
4925 atomic_inc(&epc->refcount);
4926 goto found_epc;
4927 }
4928 }
4929
4930 epc = new;
4931 new = NULL;
4932
4933 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4934 epc->ctx = ctx;
4935
4936 found_epc:
4937 if (task_ctx_data && !epc->task_ctx_data) {
4938 epc->task_ctx_data = task_ctx_data;
4939 task_ctx_data = NULL;
4940 ctx->nr_task_data++;
4941 }
4942 raw_spin_unlock_irq(&ctx->lock);
4943
4944 free_task_ctx_data(pmu, task_ctx_data);
4945 kfree(new);
4946
4947 return epc;
4948 }
4949
get_pmu_ctx(struct perf_event_pmu_context * epc)4950 static void get_pmu_ctx(struct perf_event_pmu_context *epc)
4951 {
4952 WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount));
4953 }
4954
free_epc_rcu(struct rcu_head * head)4955 static void free_epc_rcu(struct rcu_head *head)
4956 {
4957 struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head);
4958
4959 kfree(epc->task_ctx_data);
4960 kfree(epc);
4961 }
4962
put_pmu_ctx(struct perf_event_pmu_context * epc)4963 static void put_pmu_ctx(struct perf_event_pmu_context *epc)
4964 {
4965 struct perf_event_context *ctx = epc->ctx;
4966 unsigned long flags;
4967
4968 /*
4969 * XXX
4970 *
4971 * lockdep_assert_held(&ctx->mutex);
4972 *
4973 * can't because of the call-site in _free_event()/put_event()
4974 * which isn't always called under ctx->mutex.
4975 */
4976 if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags))
4977 return;
4978
4979 WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry));
4980
4981 list_del_init(&epc->pmu_ctx_entry);
4982 epc->ctx = NULL;
4983
4984 WARN_ON_ONCE(!list_empty(&epc->pinned_active));
4985 WARN_ON_ONCE(!list_empty(&epc->flexible_active));
4986
4987 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4988
4989 if (epc->embedded)
4990 return;
4991
4992 call_rcu(&epc->rcu_head, free_epc_rcu);
4993 }
4994
4995 static void perf_event_free_filter(struct perf_event *event);
4996
free_event_rcu(struct rcu_head * head)4997 static void free_event_rcu(struct rcu_head *head)
4998 {
4999 struct perf_event *event = container_of(head, typeof(*event), rcu_head);
5000
5001 if (event->ns)
5002 put_pid_ns(event->ns);
5003 perf_event_free_filter(event);
5004 kmem_cache_free(perf_event_cache, event);
5005 }
5006
5007 static void ring_buffer_attach(struct perf_event *event,
5008 struct perf_buffer *rb);
5009
detach_sb_event(struct perf_event * event)5010 static void detach_sb_event(struct perf_event *event)
5011 {
5012 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
5013
5014 raw_spin_lock(&pel->lock);
5015 list_del_rcu(&event->sb_list);
5016 raw_spin_unlock(&pel->lock);
5017 }
5018
is_sb_event(struct perf_event * event)5019 static bool is_sb_event(struct perf_event *event)
5020 {
5021 struct perf_event_attr *attr = &event->attr;
5022
5023 if (event->parent)
5024 return false;
5025
5026 if (event->attach_state & PERF_ATTACH_TASK)
5027 return false;
5028
5029 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
5030 attr->comm || attr->comm_exec ||
5031 attr->task || attr->ksymbol ||
5032 attr->context_switch || attr->text_poke ||
5033 attr->bpf_event)
5034 return true;
5035 return false;
5036 }
5037
unaccount_pmu_sb_event(struct perf_event * event)5038 static void unaccount_pmu_sb_event(struct perf_event *event)
5039 {
5040 if (is_sb_event(event))
5041 detach_sb_event(event);
5042 }
5043
5044 #ifdef CONFIG_NO_HZ_FULL
5045 static DEFINE_SPINLOCK(nr_freq_lock);
5046 #endif
5047
unaccount_freq_event_nohz(void)5048 static void unaccount_freq_event_nohz(void)
5049 {
5050 #ifdef CONFIG_NO_HZ_FULL
5051 spin_lock(&nr_freq_lock);
5052 if (atomic_dec_and_test(&nr_freq_events))
5053 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
5054 spin_unlock(&nr_freq_lock);
5055 #endif
5056 }
5057
unaccount_freq_event(void)5058 static void unaccount_freq_event(void)
5059 {
5060 if (tick_nohz_full_enabled())
5061 unaccount_freq_event_nohz();
5062 else
5063 atomic_dec(&nr_freq_events);
5064 }
5065
unaccount_event(struct perf_event * event)5066 static void unaccount_event(struct perf_event *event)
5067 {
5068 bool dec = false;
5069
5070 if (event->parent)
5071 return;
5072
5073 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
5074 dec = true;
5075 if (event->attr.mmap || event->attr.mmap_data)
5076 atomic_dec(&nr_mmap_events);
5077 if (event->attr.build_id)
5078 atomic_dec(&nr_build_id_events);
5079 if (event->attr.comm)
5080 atomic_dec(&nr_comm_events);
5081 if (event->attr.namespaces)
5082 atomic_dec(&nr_namespaces_events);
5083 if (event->attr.cgroup)
5084 atomic_dec(&nr_cgroup_events);
5085 if (event->attr.task)
5086 atomic_dec(&nr_task_events);
5087 if (event->attr.freq)
5088 unaccount_freq_event();
5089 if (event->attr.context_switch) {
5090 dec = true;
5091 atomic_dec(&nr_switch_events);
5092 }
5093 if (is_cgroup_event(event))
5094 dec = true;
5095 if (has_branch_stack(event))
5096 dec = true;
5097 if (event->attr.ksymbol)
5098 atomic_dec(&nr_ksymbol_events);
5099 if (event->attr.bpf_event)
5100 atomic_dec(&nr_bpf_events);
5101 if (event->attr.text_poke)
5102 atomic_dec(&nr_text_poke_events);
5103
5104 if (dec) {
5105 if (!atomic_add_unless(&perf_sched_count, -1, 1))
5106 schedule_delayed_work(&perf_sched_work, HZ);
5107 }
5108
5109 unaccount_pmu_sb_event(event);
5110 }
5111
perf_sched_delayed(struct work_struct * work)5112 static void perf_sched_delayed(struct work_struct *work)
5113 {
5114 mutex_lock(&perf_sched_mutex);
5115 if (atomic_dec_and_test(&perf_sched_count))
5116 static_branch_disable(&perf_sched_events);
5117 mutex_unlock(&perf_sched_mutex);
5118 }
5119
5120 /*
5121 * The following implement mutual exclusion of events on "exclusive" pmus
5122 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
5123 * at a time, so we disallow creating events that might conflict, namely:
5124 *
5125 * 1) cpu-wide events in the presence of per-task events,
5126 * 2) per-task events in the presence of cpu-wide events,
5127 * 3) two matching events on the same perf_event_context.
5128 *
5129 * The former two cases are handled in the allocation path (perf_event_alloc(),
5130 * _free_event()), the latter -- before the first perf_install_in_context().
5131 */
exclusive_event_init(struct perf_event * event)5132 static int exclusive_event_init(struct perf_event *event)
5133 {
5134 struct pmu *pmu = event->pmu;
5135
5136 if (!is_exclusive_pmu(pmu))
5137 return 0;
5138
5139 /*
5140 * Prevent co-existence of per-task and cpu-wide events on the
5141 * same exclusive pmu.
5142 *
5143 * Negative pmu::exclusive_cnt means there are cpu-wide
5144 * events on this "exclusive" pmu, positive means there are
5145 * per-task events.
5146 *
5147 * Since this is called in perf_event_alloc() path, event::ctx
5148 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
5149 * to mean "per-task event", because unlike other attach states it
5150 * never gets cleared.
5151 */
5152 if (event->attach_state & PERF_ATTACH_TASK) {
5153 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
5154 return -EBUSY;
5155 } else {
5156 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
5157 return -EBUSY;
5158 }
5159
5160 return 0;
5161 }
5162
exclusive_event_destroy(struct perf_event * event)5163 static void exclusive_event_destroy(struct perf_event *event)
5164 {
5165 struct pmu *pmu = event->pmu;
5166
5167 if (!is_exclusive_pmu(pmu))
5168 return;
5169
5170 /* see comment in exclusive_event_init() */
5171 if (event->attach_state & PERF_ATTACH_TASK)
5172 atomic_dec(&pmu->exclusive_cnt);
5173 else
5174 atomic_inc(&pmu->exclusive_cnt);
5175 }
5176
exclusive_event_match(struct perf_event * e1,struct perf_event * e2)5177 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5178 {
5179 if ((e1->pmu == e2->pmu) &&
5180 (e1->cpu == e2->cpu ||
5181 e1->cpu == -1 ||
5182 e2->cpu == -1))
5183 return true;
5184 return false;
5185 }
5186
exclusive_event_installable(struct perf_event * event,struct perf_event_context * ctx)5187 static bool exclusive_event_installable(struct perf_event *event,
5188 struct perf_event_context *ctx)
5189 {
5190 struct perf_event *iter_event;
5191 struct pmu *pmu = event->pmu;
5192
5193 lockdep_assert_held(&ctx->mutex);
5194
5195 if (!is_exclusive_pmu(pmu))
5196 return true;
5197
5198 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5199 if (exclusive_event_match(iter_event, event))
5200 return false;
5201 }
5202
5203 return true;
5204 }
5205
5206 static void perf_addr_filters_splice(struct perf_event *event,
5207 struct list_head *head);
5208
_free_event(struct perf_event * event)5209 static void _free_event(struct perf_event *event)
5210 {
5211 irq_work_sync(&event->pending_irq);
5212
5213 unaccount_event(event);
5214
5215 security_perf_event_free(event);
5216
5217 if (event->rb) {
5218 /*
5219 * Can happen when we close an event with re-directed output.
5220 *
5221 * Since we have a 0 refcount, perf_mmap_close() will skip
5222 * over us; possibly making our ring_buffer_put() the last.
5223 */
5224 mutex_lock(&event->mmap_mutex);
5225 ring_buffer_attach(event, NULL);
5226 mutex_unlock(&event->mmap_mutex);
5227 }
5228
5229 if (is_cgroup_event(event))
5230 perf_detach_cgroup(event);
5231
5232 if (!event->parent) {
5233 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5234 put_callchain_buffers();
5235 }
5236
5237 perf_event_free_bpf_prog(event);
5238 perf_addr_filters_splice(event, NULL);
5239 kfree(event->addr_filter_ranges);
5240
5241 if (event->destroy)
5242 event->destroy(event);
5243
5244 /*
5245 * Must be after ->destroy(), due to uprobe_perf_close() using
5246 * hw.target.
5247 */
5248 if (event->hw.target)
5249 put_task_struct(event->hw.target);
5250
5251 if (event->pmu_ctx)
5252 put_pmu_ctx(event->pmu_ctx);
5253
5254 /*
5255 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5256 * all task references must be cleaned up.
5257 */
5258 if (event->ctx)
5259 put_ctx(event->ctx);
5260
5261 exclusive_event_destroy(event);
5262 module_put(event->pmu->module);
5263
5264 call_rcu(&event->rcu_head, free_event_rcu);
5265 }
5266
5267 /*
5268 * Used to free events which have a known refcount of 1, such as in error paths
5269 * where the event isn't exposed yet and inherited events.
5270 */
free_event(struct perf_event * event)5271 static void free_event(struct perf_event *event)
5272 {
5273 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5274 "unexpected event refcount: %ld; ptr=%p\n",
5275 atomic_long_read(&event->refcount), event)) {
5276 /* leak to avoid use-after-free */
5277 return;
5278 }
5279
5280 _free_event(event);
5281 }
5282
5283 /*
5284 * Remove user event from the owner task.
5285 */
perf_remove_from_owner(struct perf_event * event)5286 static void perf_remove_from_owner(struct perf_event *event)
5287 {
5288 struct task_struct *owner;
5289
5290 rcu_read_lock();
5291 /*
5292 * Matches the smp_store_release() in perf_event_exit_task(). If we
5293 * observe !owner it means the list deletion is complete and we can
5294 * indeed free this event, otherwise we need to serialize on
5295 * owner->perf_event_mutex.
5296 */
5297 owner = READ_ONCE(event->owner);
5298 if (owner) {
5299 /*
5300 * Since delayed_put_task_struct() also drops the last
5301 * task reference we can safely take a new reference
5302 * while holding the rcu_read_lock().
5303 */
5304 get_task_struct(owner);
5305 }
5306 rcu_read_unlock();
5307
5308 if (owner) {
5309 /*
5310 * If we're here through perf_event_exit_task() we're already
5311 * holding ctx->mutex which would be an inversion wrt. the
5312 * normal lock order.
5313 *
5314 * However we can safely take this lock because its the child
5315 * ctx->mutex.
5316 */
5317 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5318
5319 /*
5320 * We have to re-check the event->owner field, if it is cleared
5321 * we raced with perf_event_exit_task(), acquiring the mutex
5322 * ensured they're done, and we can proceed with freeing the
5323 * event.
5324 */
5325 if (event->owner) {
5326 list_del_init(&event->owner_entry);
5327 smp_store_release(&event->owner, NULL);
5328 }
5329 mutex_unlock(&owner->perf_event_mutex);
5330 put_task_struct(owner);
5331 }
5332 }
5333
put_event(struct perf_event * event)5334 static void put_event(struct perf_event *event)
5335 {
5336 if (!atomic_long_dec_and_test(&event->refcount))
5337 return;
5338
5339 _free_event(event);
5340 }
5341
5342 /*
5343 * Kill an event dead; while event:refcount will preserve the event
5344 * object, it will not preserve its functionality. Once the last 'user'
5345 * gives up the object, we'll destroy the thing.
5346 */
perf_event_release_kernel(struct perf_event * event)5347 int perf_event_release_kernel(struct perf_event *event)
5348 {
5349 struct perf_event_context *ctx = event->ctx;
5350 struct perf_event *child, *tmp;
5351 LIST_HEAD(free_list);
5352
5353 /*
5354 * If we got here through err_alloc: free_event(event); we will not
5355 * have attached to a context yet.
5356 */
5357 if (!ctx) {
5358 WARN_ON_ONCE(event->attach_state &
5359 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5360 goto no_ctx;
5361 }
5362
5363 if (!is_kernel_event(event))
5364 perf_remove_from_owner(event);
5365
5366 ctx = perf_event_ctx_lock(event);
5367 WARN_ON_ONCE(ctx->parent_ctx);
5368
5369 /*
5370 * Mark this event as STATE_DEAD, there is no external reference to it
5371 * anymore.
5372 *
5373 * Anybody acquiring event->child_mutex after the below loop _must_
5374 * also see this, most importantly inherit_event() which will avoid
5375 * placing more children on the list.
5376 *
5377 * Thus this guarantees that we will in fact observe and kill _ALL_
5378 * child events.
5379 */
5380 perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
5381
5382 perf_event_ctx_unlock(event, ctx);
5383
5384 again:
5385 mutex_lock(&event->child_mutex);
5386 list_for_each_entry(child, &event->child_list, child_list) {
5387 void *var = NULL;
5388
5389 /*
5390 * Cannot change, child events are not migrated, see the
5391 * comment with perf_event_ctx_lock_nested().
5392 */
5393 ctx = READ_ONCE(child->ctx);
5394 /*
5395 * Since child_mutex nests inside ctx::mutex, we must jump
5396 * through hoops. We start by grabbing a reference on the ctx.
5397 *
5398 * Since the event cannot get freed while we hold the
5399 * child_mutex, the context must also exist and have a !0
5400 * reference count.
5401 */
5402 get_ctx(ctx);
5403
5404 /*
5405 * Now that we have a ctx ref, we can drop child_mutex, and
5406 * acquire ctx::mutex without fear of it going away. Then we
5407 * can re-acquire child_mutex.
5408 */
5409 mutex_unlock(&event->child_mutex);
5410 mutex_lock(&ctx->mutex);
5411 mutex_lock(&event->child_mutex);
5412
5413 /*
5414 * Now that we hold ctx::mutex and child_mutex, revalidate our
5415 * state, if child is still the first entry, it didn't get freed
5416 * and we can continue doing so.
5417 */
5418 tmp = list_first_entry_or_null(&event->child_list,
5419 struct perf_event, child_list);
5420 if (tmp == child) {
5421 perf_remove_from_context(child, DETACH_GROUP);
5422 list_move(&child->child_list, &free_list);
5423 /*
5424 * This matches the refcount bump in inherit_event();
5425 * this can't be the last reference.
5426 */
5427 put_event(event);
5428 } else {
5429 var = &ctx->refcount;
5430 }
5431
5432 mutex_unlock(&event->child_mutex);
5433 mutex_unlock(&ctx->mutex);
5434 put_ctx(ctx);
5435
5436 if (var) {
5437 /*
5438 * If perf_event_free_task() has deleted all events from the
5439 * ctx while the child_mutex got released above, make sure to
5440 * notify about the preceding put_ctx().
5441 */
5442 smp_mb(); /* pairs with wait_var_event() */
5443 wake_up_var(var);
5444 }
5445 goto again;
5446 }
5447 mutex_unlock(&event->child_mutex);
5448
5449 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5450 void *var = &child->ctx->refcount;
5451
5452 list_del(&child->child_list);
5453 free_event(child);
5454
5455 /*
5456 * Wake any perf_event_free_task() waiting for this event to be
5457 * freed.
5458 */
5459 smp_mb(); /* pairs with wait_var_event() */
5460 wake_up_var(var);
5461 }
5462
5463 no_ctx:
5464 put_event(event); /* Must be the 'last' reference */
5465 return 0;
5466 }
5467 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5468
5469 /*
5470 * Called when the last reference to the file is gone.
5471 */
perf_release(struct inode * inode,struct file * file)5472 static int perf_release(struct inode *inode, struct file *file)
5473 {
5474 perf_event_release_kernel(file->private_data);
5475 return 0;
5476 }
5477
__perf_event_read_value(struct perf_event * event,u64 * enabled,u64 * running)5478 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5479 {
5480 struct perf_event *child;
5481 u64 total = 0;
5482
5483 *enabled = 0;
5484 *running = 0;
5485
5486 mutex_lock(&event->child_mutex);
5487
5488 (void)perf_event_read(event, false);
5489 total += perf_event_count(event);
5490
5491 *enabled += event->total_time_enabled +
5492 atomic64_read(&event->child_total_time_enabled);
5493 *running += event->total_time_running +
5494 atomic64_read(&event->child_total_time_running);
5495
5496 list_for_each_entry(child, &event->child_list, child_list) {
5497 (void)perf_event_read(child, false);
5498 total += perf_event_count(child);
5499 *enabled += child->total_time_enabled;
5500 *running += child->total_time_running;
5501 }
5502 mutex_unlock(&event->child_mutex);
5503
5504 return total;
5505 }
5506
perf_event_read_value(struct perf_event * event,u64 * enabled,u64 * running)5507 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5508 {
5509 struct perf_event_context *ctx;
5510 u64 count;
5511
5512 ctx = perf_event_ctx_lock(event);
5513 count = __perf_event_read_value(event, enabled, running);
5514 perf_event_ctx_unlock(event, ctx);
5515
5516 return count;
5517 }
5518 EXPORT_SYMBOL_GPL(perf_event_read_value);
5519
__perf_read_group_add(struct perf_event * leader,u64 read_format,u64 * values)5520 static int __perf_read_group_add(struct perf_event *leader,
5521 u64 read_format, u64 *values)
5522 {
5523 struct perf_event_context *ctx = leader->ctx;
5524 struct perf_event *sub, *parent;
5525 unsigned long flags;
5526 int n = 1; /* skip @nr */
5527 int ret;
5528
5529 ret = perf_event_read(leader, true);
5530 if (ret)
5531 return ret;
5532
5533 raw_spin_lock_irqsave(&ctx->lock, flags);
5534 /*
5535 * Verify the grouping between the parent and child (inherited)
5536 * events is still in tact.
5537 *
5538 * Specifically:
5539 * - leader->ctx->lock pins leader->sibling_list
5540 * - parent->child_mutex pins parent->child_list
5541 * - parent->ctx->mutex pins parent->sibling_list
5542 *
5543 * Because parent->ctx != leader->ctx (and child_list nests inside
5544 * ctx->mutex), group destruction is not atomic between children, also
5545 * see perf_event_release_kernel(). Additionally, parent can grow the
5546 * group.
5547 *
5548 * Therefore it is possible to have parent and child groups in a
5549 * different configuration and summing over such a beast makes no sense
5550 * what so ever.
5551 *
5552 * Reject this.
5553 */
5554 parent = leader->parent;
5555 if (parent &&
5556 (parent->group_generation != leader->group_generation ||
5557 parent->nr_siblings != leader->nr_siblings)) {
5558 ret = -ECHILD;
5559 goto unlock;
5560 }
5561
5562 /*
5563 * Since we co-schedule groups, {enabled,running} times of siblings
5564 * will be identical to those of the leader, so we only publish one
5565 * set.
5566 */
5567 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5568 values[n++] += leader->total_time_enabled +
5569 atomic64_read(&leader->child_total_time_enabled);
5570 }
5571
5572 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5573 values[n++] += leader->total_time_running +
5574 atomic64_read(&leader->child_total_time_running);
5575 }
5576
5577 /*
5578 * Write {count,id} tuples for every sibling.
5579 */
5580 values[n++] += perf_event_count(leader);
5581 if (read_format & PERF_FORMAT_ID)
5582 values[n++] = primary_event_id(leader);
5583 if (read_format & PERF_FORMAT_LOST)
5584 values[n++] = atomic64_read(&leader->lost_samples);
5585
5586 for_each_sibling_event(sub, leader) {
5587 values[n++] += perf_event_count(sub);
5588 if (read_format & PERF_FORMAT_ID)
5589 values[n++] = primary_event_id(sub);
5590 if (read_format & PERF_FORMAT_LOST)
5591 values[n++] = atomic64_read(&sub->lost_samples);
5592 }
5593
5594 unlock:
5595 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5596 return ret;
5597 }
5598
perf_read_group(struct perf_event * event,u64 read_format,char __user * buf)5599 static int perf_read_group(struct perf_event *event,
5600 u64 read_format, char __user *buf)
5601 {
5602 struct perf_event *leader = event->group_leader, *child;
5603 struct perf_event_context *ctx = leader->ctx;
5604 int ret;
5605 u64 *values;
5606
5607 lockdep_assert_held(&ctx->mutex);
5608
5609 values = kzalloc(event->read_size, GFP_KERNEL);
5610 if (!values)
5611 return -ENOMEM;
5612
5613 values[0] = 1 + leader->nr_siblings;
5614
5615 mutex_lock(&leader->child_mutex);
5616
5617 ret = __perf_read_group_add(leader, read_format, values);
5618 if (ret)
5619 goto unlock;
5620
5621 list_for_each_entry(child, &leader->child_list, child_list) {
5622 ret = __perf_read_group_add(child, read_format, values);
5623 if (ret)
5624 goto unlock;
5625 }
5626
5627 mutex_unlock(&leader->child_mutex);
5628
5629 ret = event->read_size;
5630 if (copy_to_user(buf, values, event->read_size))
5631 ret = -EFAULT;
5632 goto out;
5633
5634 unlock:
5635 mutex_unlock(&leader->child_mutex);
5636 out:
5637 kfree(values);
5638 return ret;
5639 }
5640
perf_read_one(struct perf_event * event,u64 read_format,char __user * buf)5641 static int perf_read_one(struct perf_event *event,
5642 u64 read_format, char __user *buf)
5643 {
5644 u64 enabled, running;
5645 u64 values[5];
5646 int n = 0;
5647
5648 values[n++] = __perf_event_read_value(event, &enabled, &running);
5649 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5650 values[n++] = enabled;
5651 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5652 values[n++] = running;
5653 if (read_format & PERF_FORMAT_ID)
5654 values[n++] = primary_event_id(event);
5655 if (read_format & PERF_FORMAT_LOST)
5656 values[n++] = atomic64_read(&event->lost_samples);
5657
5658 if (copy_to_user(buf, values, n * sizeof(u64)))
5659 return -EFAULT;
5660
5661 return n * sizeof(u64);
5662 }
5663
is_event_hup(struct perf_event * event)5664 static bool is_event_hup(struct perf_event *event)
5665 {
5666 bool no_children;
5667
5668 if (event->state > PERF_EVENT_STATE_EXIT)
5669 return false;
5670
5671 mutex_lock(&event->child_mutex);
5672 no_children = list_empty(&event->child_list);
5673 mutex_unlock(&event->child_mutex);
5674 return no_children;
5675 }
5676
5677 /*
5678 * Read the performance event - simple non blocking version for now
5679 */
5680 static ssize_t
__perf_read(struct perf_event * event,char __user * buf,size_t count)5681 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5682 {
5683 u64 read_format = event->attr.read_format;
5684 int ret;
5685
5686 /*
5687 * Return end-of-file for a read on an event that is in
5688 * error state (i.e. because it was pinned but it couldn't be
5689 * scheduled on to the CPU at some point).
5690 */
5691 if (event->state == PERF_EVENT_STATE_ERROR)
5692 return 0;
5693
5694 if (count < event->read_size)
5695 return -ENOSPC;
5696
5697 WARN_ON_ONCE(event->ctx->parent_ctx);
5698 if (read_format & PERF_FORMAT_GROUP)
5699 ret = perf_read_group(event, read_format, buf);
5700 else
5701 ret = perf_read_one(event, read_format, buf);
5702
5703 return ret;
5704 }
5705
5706 static ssize_t
perf_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)5707 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5708 {
5709 struct perf_event *event = file->private_data;
5710 struct perf_event_context *ctx;
5711 int ret;
5712
5713 ret = security_perf_event_read(event);
5714 if (ret)
5715 return ret;
5716
5717 ctx = perf_event_ctx_lock(event);
5718 ret = __perf_read(event, buf, count);
5719 perf_event_ctx_unlock(event, ctx);
5720
5721 return ret;
5722 }
5723
perf_poll(struct file * file,poll_table * wait)5724 static __poll_t perf_poll(struct file *file, poll_table *wait)
5725 {
5726 struct perf_event *event = file->private_data;
5727 struct perf_buffer *rb;
5728 __poll_t events = EPOLLHUP;
5729
5730 poll_wait(file, &event->waitq, wait);
5731
5732 if (is_event_hup(event))
5733 return events;
5734
5735 /*
5736 * Pin the event->rb by taking event->mmap_mutex; otherwise
5737 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5738 */
5739 mutex_lock(&event->mmap_mutex);
5740 rb = event->rb;
5741 if (rb)
5742 events = atomic_xchg(&rb->poll, 0);
5743 mutex_unlock(&event->mmap_mutex);
5744 return events;
5745 }
5746
_perf_event_reset(struct perf_event * event)5747 static void _perf_event_reset(struct perf_event *event)
5748 {
5749 (void)perf_event_read(event, false);
5750 local64_set(&event->count, 0);
5751 perf_event_update_userpage(event);
5752 }
5753
5754 /* Assume it's not an event with inherit set. */
perf_event_pause(struct perf_event * event,bool reset)5755 u64 perf_event_pause(struct perf_event *event, bool reset)
5756 {
5757 struct perf_event_context *ctx;
5758 u64 count;
5759
5760 ctx = perf_event_ctx_lock(event);
5761 WARN_ON_ONCE(event->attr.inherit);
5762 _perf_event_disable(event);
5763 count = local64_read(&event->count);
5764 if (reset)
5765 local64_set(&event->count, 0);
5766 perf_event_ctx_unlock(event, ctx);
5767
5768 return count;
5769 }
5770 EXPORT_SYMBOL_GPL(perf_event_pause);
5771
5772 /*
5773 * Holding the top-level event's child_mutex means that any
5774 * descendant process that has inherited this event will block
5775 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5776 * task existence requirements of perf_event_enable/disable.
5777 */
perf_event_for_each_child(struct perf_event * event,void (* func)(struct perf_event *))5778 static void perf_event_for_each_child(struct perf_event *event,
5779 void (*func)(struct perf_event *))
5780 {
5781 struct perf_event *child;
5782
5783 WARN_ON_ONCE(event->ctx->parent_ctx);
5784
5785 mutex_lock(&event->child_mutex);
5786 func(event);
5787 list_for_each_entry(child, &event->child_list, child_list)
5788 func(child);
5789 mutex_unlock(&event->child_mutex);
5790 }
5791
perf_event_for_each(struct perf_event * event,void (* func)(struct perf_event *))5792 static void perf_event_for_each(struct perf_event *event,
5793 void (*func)(struct perf_event *))
5794 {
5795 struct perf_event_context *ctx = event->ctx;
5796 struct perf_event *sibling;
5797
5798 lockdep_assert_held(&ctx->mutex);
5799
5800 event = event->group_leader;
5801
5802 perf_event_for_each_child(event, func);
5803 for_each_sibling_event(sibling, event)
5804 perf_event_for_each_child(sibling, func);
5805 }
5806
__perf_event_period(struct perf_event * event,struct perf_cpu_context * cpuctx,struct perf_event_context * ctx,void * info)5807 static void __perf_event_period(struct perf_event *event,
5808 struct perf_cpu_context *cpuctx,
5809 struct perf_event_context *ctx,
5810 void *info)
5811 {
5812 u64 value = *((u64 *)info);
5813 bool active;
5814
5815 if (event->attr.freq) {
5816 event->attr.sample_freq = value;
5817 } else {
5818 event->attr.sample_period = value;
5819 event->hw.sample_period = value;
5820 }
5821
5822 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5823 if (active) {
5824 perf_pmu_disable(event->pmu);
5825 /*
5826 * We could be throttled; unthrottle now to avoid the tick
5827 * trying to unthrottle while we already re-started the event.
5828 */
5829 if (event->hw.interrupts == MAX_INTERRUPTS) {
5830 event->hw.interrupts = 0;
5831 perf_log_throttle(event, 1);
5832 }
5833 event->pmu->stop(event, PERF_EF_UPDATE);
5834 }
5835
5836 local64_set(&event->hw.period_left, 0);
5837
5838 if (active) {
5839 event->pmu->start(event, PERF_EF_RELOAD);
5840 perf_pmu_enable(event->pmu);
5841 }
5842 }
5843
perf_event_check_period(struct perf_event * event,u64 value)5844 static int perf_event_check_period(struct perf_event *event, u64 value)
5845 {
5846 return event->pmu->check_period(event, value);
5847 }
5848
_perf_event_period(struct perf_event * event,u64 value)5849 static int _perf_event_period(struct perf_event *event, u64 value)
5850 {
5851 if (!is_sampling_event(event))
5852 return -EINVAL;
5853
5854 if (!value)
5855 return -EINVAL;
5856
5857 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5858 return -EINVAL;
5859
5860 if (perf_event_check_period(event, value))
5861 return -EINVAL;
5862
5863 if (!event->attr.freq && (value & (1ULL << 63)))
5864 return -EINVAL;
5865
5866 event_function_call(event, __perf_event_period, &value);
5867
5868 return 0;
5869 }
5870
perf_event_period(struct perf_event * event,u64 value)5871 int perf_event_period(struct perf_event *event, u64 value)
5872 {
5873 struct perf_event_context *ctx;
5874 int ret;
5875
5876 ctx = perf_event_ctx_lock(event);
5877 ret = _perf_event_period(event, value);
5878 perf_event_ctx_unlock(event, ctx);
5879
5880 return ret;
5881 }
5882 EXPORT_SYMBOL_GPL(perf_event_period);
5883
5884 static const struct file_operations perf_fops;
5885
perf_fget_light(int fd,struct fd * p)5886 static inline int perf_fget_light(int fd, struct fd *p)
5887 {
5888 struct fd f = fdget(fd);
5889 if (!f.file)
5890 return -EBADF;
5891
5892 if (f.file->f_op != &perf_fops) {
5893 fdput(f);
5894 return -EBADF;
5895 }
5896 *p = f;
5897 return 0;
5898 }
5899
5900 static int perf_event_set_output(struct perf_event *event,
5901 struct perf_event *output_event);
5902 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5903 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5904 struct perf_event_attr *attr);
5905
_perf_ioctl(struct perf_event * event,unsigned int cmd,unsigned long arg)5906 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5907 {
5908 void (*func)(struct perf_event *);
5909 u32 flags = arg;
5910
5911 switch (cmd) {
5912 case PERF_EVENT_IOC_ENABLE:
5913 func = _perf_event_enable;
5914 break;
5915 case PERF_EVENT_IOC_DISABLE:
5916 func = _perf_event_disable;
5917 break;
5918 case PERF_EVENT_IOC_RESET:
5919 func = _perf_event_reset;
5920 break;
5921
5922 case PERF_EVENT_IOC_REFRESH:
5923 return _perf_event_refresh(event, arg);
5924
5925 case PERF_EVENT_IOC_PERIOD:
5926 {
5927 u64 value;
5928
5929 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5930 return -EFAULT;
5931
5932 return _perf_event_period(event, value);
5933 }
5934 case PERF_EVENT_IOC_ID:
5935 {
5936 u64 id = primary_event_id(event);
5937
5938 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5939 return -EFAULT;
5940 return 0;
5941 }
5942
5943 case PERF_EVENT_IOC_SET_OUTPUT:
5944 {
5945 int ret;
5946 if (arg != -1) {
5947 struct perf_event *output_event;
5948 struct fd output;
5949 ret = perf_fget_light(arg, &output);
5950 if (ret)
5951 return ret;
5952 output_event = output.file->private_data;
5953 ret = perf_event_set_output(event, output_event);
5954 fdput(output);
5955 } else {
5956 ret = perf_event_set_output(event, NULL);
5957 }
5958 return ret;
5959 }
5960
5961 case PERF_EVENT_IOC_SET_FILTER:
5962 return perf_event_set_filter(event, (void __user *)arg);
5963
5964 case PERF_EVENT_IOC_SET_BPF:
5965 {
5966 struct bpf_prog *prog;
5967 int err;
5968
5969 prog = bpf_prog_get(arg);
5970 if (IS_ERR(prog))
5971 return PTR_ERR(prog);
5972
5973 err = perf_event_set_bpf_prog(event, prog, 0);
5974 if (err) {
5975 bpf_prog_put(prog);
5976 return err;
5977 }
5978
5979 return 0;
5980 }
5981
5982 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5983 struct perf_buffer *rb;
5984
5985 rcu_read_lock();
5986 rb = rcu_dereference(event->rb);
5987 if (!rb || !rb->nr_pages) {
5988 rcu_read_unlock();
5989 return -EINVAL;
5990 }
5991 rb_toggle_paused(rb, !!arg);
5992 rcu_read_unlock();
5993 return 0;
5994 }
5995
5996 case PERF_EVENT_IOC_QUERY_BPF:
5997 return perf_event_query_prog_array(event, (void __user *)arg);
5998
5999 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
6000 struct perf_event_attr new_attr;
6001 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
6002 &new_attr);
6003
6004 if (err)
6005 return err;
6006
6007 return perf_event_modify_attr(event, &new_attr);
6008 }
6009 default:
6010 return -ENOTTY;
6011 }
6012
6013 if (flags & PERF_IOC_FLAG_GROUP)
6014 perf_event_for_each(event, func);
6015 else
6016 perf_event_for_each_child(event, func);
6017
6018 return 0;
6019 }
6020
perf_ioctl(struct file * file,unsigned int cmd,unsigned long arg)6021 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
6022 {
6023 struct perf_event *event = file->private_data;
6024 struct perf_event_context *ctx;
6025 long ret;
6026
6027 /* Treat ioctl like writes as it is likely a mutating operation. */
6028 ret = security_perf_event_write(event);
6029 if (ret)
6030 return ret;
6031
6032 ctx = perf_event_ctx_lock(event);
6033 ret = _perf_ioctl(event, cmd, arg);
6034 perf_event_ctx_unlock(event, ctx);
6035
6036 return ret;
6037 }
6038
6039 #ifdef CONFIG_COMPAT
perf_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)6040 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
6041 unsigned long arg)
6042 {
6043 switch (_IOC_NR(cmd)) {
6044 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
6045 case _IOC_NR(PERF_EVENT_IOC_ID):
6046 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
6047 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
6048 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
6049 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
6050 cmd &= ~IOCSIZE_MASK;
6051 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
6052 }
6053 break;
6054 }
6055 return perf_ioctl(file, cmd, arg);
6056 }
6057 #else
6058 # define perf_compat_ioctl NULL
6059 #endif
6060
perf_event_task_enable(void)6061 int perf_event_task_enable(void)
6062 {
6063 struct perf_event_context *ctx;
6064 struct perf_event *event;
6065
6066 mutex_lock(¤t->perf_event_mutex);
6067 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
6068 ctx = perf_event_ctx_lock(event);
6069 perf_event_for_each_child(event, _perf_event_enable);
6070 perf_event_ctx_unlock(event, ctx);
6071 }
6072 mutex_unlock(¤t->perf_event_mutex);
6073
6074 return 0;
6075 }
6076
perf_event_task_disable(void)6077 int perf_event_task_disable(void)
6078 {
6079 struct perf_event_context *ctx;
6080 struct perf_event *event;
6081
6082 mutex_lock(¤t->perf_event_mutex);
6083 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
6084 ctx = perf_event_ctx_lock(event);
6085 perf_event_for_each_child(event, _perf_event_disable);
6086 perf_event_ctx_unlock(event, ctx);
6087 }
6088 mutex_unlock(¤t->perf_event_mutex);
6089
6090 return 0;
6091 }
6092
perf_event_index(struct perf_event * event)6093 static int perf_event_index(struct perf_event *event)
6094 {
6095 if (event->hw.state & PERF_HES_STOPPED)
6096 return 0;
6097
6098 if (event->state != PERF_EVENT_STATE_ACTIVE)
6099 return 0;
6100
6101 return event->pmu->event_idx(event);
6102 }
6103
perf_event_init_userpage(struct perf_event * event)6104 static void perf_event_init_userpage(struct perf_event *event)
6105 {
6106 struct perf_event_mmap_page *userpg;
6107 struct perf_buffer *rb;
6108
6109 rcu_read_lock();
6110 rb = rcu_dereference(event->rb);
6111 if (!rb)
6112 goto unlock;
6113
6114 userpg = rb->user_page;
6115
6116 /* Allow new userspace to detect that bit 0 is deprecated */
6117 userpg->cap_bit0_is_deprecated = 1;
6118 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
6119 userpg->data_offset = PAGE_SIZE;
6120 userpg->data_size = perf_data_size(rb);
6121
6122 unlock:
6123 rcu_read_unlock();
6124 }
6125
arch_perf_update_userpage(struct perf_event * event,struct perf_event_mmap_page * userpg,u64 now)6126 void __weak arch_perf_update_userpage(
6127 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
6128 {
6129 }
6130
6131 /*
6132 * Callers need to ensure there can be no nesting of this function, otherwise
6133 * the seqlock logic goes bad. We can not serialize this because the arch
6134 * code calls this from NMI context.
6135 */
perf_event_update_userpage(struct perf_event * event)6136 void perf_event_update_userpage(struct perf_event *event)
6137 {
6138 struct perf_event_mmap_page *userpg;
6139 struct perf_buffer *rb;
6140 u64 enabled, running, now;
6141
6142 rcu_read_lock();
6143 rb = rcu_dereference(event->rb);
6144 if (!rb)
6145 goto unlock;
6146
6147 /*
6148 * compute total_time_enabled, total_time_running
6149 * based on snapshot values taken when the event
6150 * was last scheduled in.
6151 *
6152 * we cannot simply called update_context_time()
6153 * because of locking issue as we can be called in
6154 * NMI context
6155 */
6156 calc_timer_values(event, &now, &enabled, &running);
6157
6158 userpg = rb->user_page;
6159 /*
6160 * Disable preemption to guarantee consistent time stamps are stored to
6161 * the user page.
6162 */
6163 preempt_disable();
6164 ++userpg->lock;
6165 barrier();
6166 userpg->index = perf_event_index(event);
6167 userpg->offset = perf_event_count(event);
6168 if (userpg->index)
6169 userpg->offset -= local64_read(&event->hw.prev_count);
6170
6171 userpg->time_enabled = enabled +
6172 atomic64_read(&event->child_total_time_enabled);
6173
6174 userpg->time_running = running +
6175 atomic64_read(&event->child_total_time_running);
6176
6177 arch_perf_update_userpage(event, userpg, now);
6178
6179 barrier();
6180 ++userpg->lock;
6181 preempt_enable();
6182 unlock:
6183 rcu_read_unlock();
6184 }
6185 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
6186
perf_mmap_fault(struct vm_fault * vmf)6187 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
6188 {
6189 struct perf_event *event = vmf->vma->vm_file->private_data;
6190 struct perf_buffer *rb;
6191 vm_fault_t ret = VM_FAULT_SIGBUS;
6192
6193 if (vmf->flags & FAULT_FLAG_MKWRITE) {
6194 if (vmf->pgoff == 0)
6195 ret = 0;
6196 return ret;
6197 }
6198
6199 rcu_read_lock();
6200 rb = rcu_dereference(event->rb);
6201 if (!rb)
6202 goto unlock;
6203
6204 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
6205 goto unlock;
6206
6207 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
6208 if (!vmf->page)
6209 goto unlock;
6210
6211 get_page(vmf->page);
6212 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
6213 vmf->page->index = vmf->pgoff;
6214
6215 ret = 0;
6216 unlock:
6217 rcu_read_unlock();
6218
6219 return ret;
6220 }
6221
ring_buffer_attach(struct perf_event * event,struct perf_buffer * rb)6222 static void ring_buffer_attach(struct perf_event *event,
6223 struct perf_buffer *rb)
6224 {
6225 struct perf_buffer *old_rb = NULL;
6226 unsigned long flags;
6227
6228 WARN_ON_ONCE(event->parent);
6229
6230 if (event->rb) {
6231 /*
6232 * Should be impossible, we set this when removing
6233 * event->rb_entry and wait/clear when adding event->rb_entry.
6234 */
6235 WARN_ON_ONCE(event->rcu_pending);
6236
6237 old_rb = event->rb;
6238 spin_lock_irqsave(&old_rb->event_lock, flags);
6239 list_del_rcu(&event->rb_entry);
6240 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6241
6242 event->rcu_batches = get_state_synchronize_rcu();
6243 event->rcu_pending = 1;
6244 }
6245
6246 if (rb) {
6247 if (event->rcu_pending) {
6248 cond_synchronize_rcu(event->rcu_batches);
6249 event->rcu_pending = 0;
6250 }
6251
6252 spin_lock_irqsave(&rb->event_lock, flags);
6253 list_add_rcu(&event->rb_entry, &rb->event_list);
6254 spin_unlock_irqrestore(&rb->event_lock, flags);
6255 }
6256
6257 /*
6258 * Avoid racing with perf_mmap_close(AUX): stop the event
6259 * before swizzling the event::rb pointer; if it's getting
6260 * unmapped, its aux_mmap_count will be 0 and it won't
6261 * restart. See the comment in __perf_pmu_output_stop().
6262 *
6263 * Data will inevitably be lost when set_output is done in
6264 * mid-air, but then again, whoever does it like this is
6265 * not in for the data anyway.
6266 */
6267 if (has_aux(event))
6268 perf_event_stop(event, 0);
6269
6270 rcu_assign_pointer(event->rb, rb);
6271
6272 if (old_rb) {
6273 ring_buffer_put(old_rb);
6274 /*
6275 * Since we detached before setting the new rb, so that we
6276 * could attach the new rb, we could have missed a wakeup.
6277 * Provide it now.
6278 */
6279 wake_up_all(&event->waitq);
6280 }
6281 }
6282
ring_buffer_wakeup(struct perf_event * event)6283 static void ring_buffer_wakeup(struct perf_event *event)
6284 {
6285 struct perf_buffer *rb;
6286
6287 if (event->parent)
6288 event = event->parent;
6289
6290 rcu_read_lock();
6291 rb = rcu_dereference(event->rb);
6292 if (rb) {
6293 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6294 wake_up_all(&event->waitq);
6295 }
6296 rcu_read_unlock();
6297 }
6298
ring_buffer_get(struct perf_event * event)6299 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6300 {
6301 struct perf_buffer *rb;
6302
6303 if (event->parent)
6304 event = event->parent;
6305
6306 rcu_read_lock();
6307 rb = rcu_dereference(event->rb);
6308 if (rb) {
6309 if (!refcount_inc_not_zero(&rb->refcount))
6310 rb = NULL;
6311 }
6312 rcu_read_unlock();
6313
6314 return rb;
6315 }
6316
ring_buffer_put(struct perf_buffer * rb)6317 void ring_buffer_put(struct perf_buffer *rb)
6318 {
6319 if (!refcount_dec_and_test(&rb->refcount))
6320 return;
6321
6322 WARN_ON_ONCE(!list_empty(&rb->event_list));
6323
6324 call_rcu(&rb->rcu_head, rb_free_rcu);
6325 }
6326
perf_mmap_open(struct vm_area_struct * vma)6327 static void perf_mmap_open(struct vm_area_struct *vma)
6328 {
6329 struct perf_event *event = vma->vm_file->private_data;
6330
6331 atomic_inc(&event->mmap_count);
6332 atomic_inc(&event->rb->mmap_count);
6333
6334 if (vma->vm_pgoff)
6335 atomic_inc(&event->rb->aux_mmap_count);
6336
6337 if (event->pmu->event_mapped)
6338 event->pmu->event_mapped(event, vma->vm_mm);
6339 }
6340
6341 static void perf_pmu_output_stop(struct perf_event *event);
6342
6343 /*
6344 * A buffer can be mmap()ed multiple times; either directly through the same
6345 * event, or through other events by use of perf_event_set_output().
6346 *
6347 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6348 * the buffer here, where we still have a VM context. This means we need
6349 * to detach all events redirecting to us.
6350 */
perf_mmap_close(struct vm_area_struct * vma)6351 static void perf_mmap_close(struct vm_area_struct *vma)
6352 {
6353 struct perf_event *event = vma->vm_file->private_data;
6354 struct perf_buffer *rb = ring_buffer_get(event);
6355 struct user_struct *mmap_user = rb->mmap_user;
6356 int mmap_locked = rb->mmap_locked;
6357 unsigned long size = perf_data_size(rb);
6358 bool detach_rest = false;
6359
6360 if (event->pmu->event_unmapped)
6361 event->pmu->event_unmapped(event, vma->vm_mm);
6362
6363 /*
6364 * rb->aux_mmap_count will always drop before rb->mmap_count and
6365 * event->mmap_count, so it is ok to use event->mmap_mutex to
6366 * serialize with perf_mmap here.
6367 */
6368 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6369 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6370 /*
6371 * Stop all AUX events that are writing to this buffer,
6372 * so that we can free its AUX pages and corresponding PMU
6373 * data. Note that after rb::aux_mmap_count dropped to zero,
6374 * they won't start any more (see perf_aux_output_begin()).
6375 */
6376 perf_pmu_output_stop(event);
6377
6378 /* now it's safe to free the pages */
6379 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6380 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6381
6382 /* this has to be the last one */
6383 rb_free_aux(rb);
6384 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6385
6386 mutex_unlock(&event->mmap_mutex);
6387 }
6388
6389 if (atomic_dec_and_test(&rb->mmap_count))
6390 detach_rest = true;
6391
6392 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6393 goto out_put;
6394
6395 ring_buffer_attach(event, NULL);
6396 mutex_unlock(&event->mmap_mutex);
6397
6398 /* If there's still other mmap()s of this buffer, we're done. */
6399 if (!detach_rest)
6400 goto out_put;
6401
6402 /*
6403 * No other mmap()s, detach from all other events that might redirect
6404 * into the now unreachable buffer. Somewhat complicated by the
6405 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6406 */
6407 again:
6408 rcu_read_lock();
6409 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6410 if (!atomic_long_inc_not_zero(&event->refcount)) {
6411 /*
6412 * This event is en-route to free_event() which will
6413 * detach it and remove it from the list.
6414 */
6415 continue;
6416 }
6417 rcu_read_unlock();
6418
6419 mutex_lock(&event->mmap_mutex);
6420 /*
6421 * Check we didn't race with perf_event_set_output() which can
6422 * swizzle the rb from under us while we were waiting to
6423 * acquire mmap_mutex.
6424 *
6425 * If we find a different rb; ignore this event, a next
6426 * iteration will no longer find it on the list. We have to
6427 * still restart the iteration to make sure we're not now
6428 * iterating the wrong list.
6429 */
6430 if (event->rb == rb)
6431 ring_buffer_attach(event, NULL);
6432
6433 mutex_unlock(&event->mmap_mutex);
6434 put_event(event);
6435
6436 /*
6437 * Restart the iteration; either we're on the wrong list or
6438 * destroyed its integrity by doing a deletion.
6439 */
6440 goto again;
6441 }
6442 rcu_read_unlock();
6443
6444 /*
6445 * It could be there's still a few 0-ref events on the list; they'll
6446 * get cleaned up by free_event() -- they'll also still have their
6447 * ref on the rb and will free it whenever they are done with it.
6448 *
6449 * Aside from that, this buffer is 'fully' detached and unmapped,
6450 * undo the VM accounting.
6451 */
6452
6453 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6454 &mmap_user->locked_vm);
6455 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6456 free_uid(mmap_user);
6457
6458 out_put:
6459 ring_buffer_put(rb); /* could be last */
6460 }
6461
6462 static const struct vm_operations_struct perf_mmap_vmops = {
6463 .open = perf_mmap_open,
6464 .close = perf_mmap_close, /* non mergeable */
6465 .fault = perf_mmap_fault,
6466 .page_mkwrite = perf_mmap_fault,
6467 };
6468
perf_mmap(struct file * file,struct vm_area_struct * vma)6469 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6470 {
6471 struct perf_event *event = file->private_data;
6472 unsigned long user_locked, user_lock_limit;
6473 struct user_struct *user = current_user();
6474 struct perf_buffer *rb = NULL;
6475 unsigned long locked, lock_limit;
6476 unsigned long vma_size;
6477 unsigned long nr_pages;
6478 long user_extra = 0, extra = 0;
6479 int ret = 0, flags = 0;
6480
6481 /*
6482 * Don't allow mmap() of inherited per-task counters. This would
6483 * create a performance issue due to all children writing to the
6484 * same rb.
6485 */
6486 if (event->cpu == -1 && event->attr.inherit)
6487 return -EINVAL;
6488
6489 if (!(vma->vm_flags & VM_SHARED))
6490 return -EINVAL;
6491
6492 ret = security_perf_event_read(event);
6493 if (ret)
6494 return ret;
6495
6496 vma_size = vma->vm_end - vma->vm_start;
6497
6498 if (vma->vm_pgoff == 0) {
6499 nr_pages = (vma_size / PAGE_SIZE) - 1;
6500 } else {
6501 /*
6502 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6503 * mapped, all subsequent mappings should have the same size
6504 * and offset. Must be above the normal perf buffer.
6505 */
6506 u64 aux_offset, aux_size;
6507
6508 if (!event->rb)
6509 return -EINVAL;
6510
6511 nr_pages = vma_size / PAGE_SIZE;
6512
6513 mutex_lock(&event->mmap_mutex);
6514 ret = -EINVAL;
6515
6516 rb = event->rb;
6517 if (!rb)
6518 goto aux_unlock;
6519
6520 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6521 aux_size = READ_ONCE(rb->user_page->aux_size);
6522
6523 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6524 goto aux_unlock;
6525
6526 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6527 goto aux_unlock;
6528
6529 /* already mapped with a different offset */
6530 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6531 goto aux_unlock;
6532
6533 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6534 goto aux_unlock;
6535
6536 /* already mapped with a different size */
6537 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6538 goto aux_unlock;
6539
6540 if (!is_power_of_2(nr_pages))
6541 goto aux_unlock;
6542
6543 if (!atomic_inc_not_zero(&rb->mmap_count))
6544 goto aux_unlock;
6545
6546 if (rb_has_aux(rb)) {
6547 atomic_inc(&rb->aux_mmap_count);
6548 ret = 0;
6549 goto unlock;
6550 }
6551
6552 atomic_set(&rb->aux_mmap_count, 1);
6553 user_extra = nr_pages;
6554
6555 goto accounting;
6556 }
6557
6558 /*
6559 * If we have rb pages ensure they're a power-of-two number, so we
6560 * can do bitmasks instead of modulo.
6561 */
6562 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6563 return -EINVAL;
6564
6565 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6566 return -EINVAL;
6567
6568 WARN_ON_ONCE(event->ctx->parent_ctx);
6569 again:
6570 mutex_lock(&event->mmap_mutex);
6571 if (event->rb) {
6572 if (data_page_nr(event->rb) != nr_pages) {
6573 ret = -EINVAL;
6574 goto unlock;
6575 }
6576
6577 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6578 /*
6579 * Raced against perf_mmap_close(); remove the
6580 * event and try again.
6581 */
6582 ring_buffer_attach(event, NULL);
6583 mutex_unlock(&event->mmap_mutex);
6584 goto again;
6585 }
6586
6587 goto unlock;
6588 }
6589
6590 user_extra = nr_pages + 1;
6591
6592 accounting:
6593 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6594
6595 /*
6596 * Increase the limit linearly with more CPUs:
6597 */
6598 user_lock_limit *= num_online_cpus();
6599
6600 user_locked = atomic_long_read(&user->locked_vm);
6601
6602 /*
6603 * sysctl_perf_event_mlock may have changed, so that
6604 * user->locked_vm > user_lock_limit
6605 */
6606 if (user_locked > user_lock_limit)
6607 user_locked = user_lock_limit;
6608 user_locked += user_extra;
6609
6610 if (user_locked > user_lock_limit) {
6611 /*
6612 * charge locked_vm until it hits user_lock_limit;
6613 * charge the rest from pinned_vm
6614 */
6615 extra = user_locked - user_lock_limit;
6616 user_extra -= extra;
6617 }
6618
6619 lock_limit = rlimit(RLIMIT_MEMLOCK);
6620 lock_limit >>= PAGE_SHIFT;
6621 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6622
6623 if ((locked > lock_limit) && perf_is_paranoid() &&
6624 !capable(CAP_IPC_LOCK)) {
6625 ret = -EPERM;
6626 goto unlock;
6627 }
6628
6629 WARN_ON(!rb && event->rb);
6630
6631 if (vma->vm_flags & VM_WRITE)
6632 flags |= RING_BUFFER_WRITABLE;
6633
6634 if (!rb) {
6635 rb = rb_alloc(nr_pages,
6636 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6637 event->cpu, flags);
6638
6639 if (!rb) {
6640 ret = -ENOMEM;
6641 goto unlock;
6642 }
6643
6644 atomic_set(&rb->mmap_count, 1);
6645 rb->mmap_user = get_current_user();
6646 rb->mmap_locked = extra;
6647
6648 ring_buffer_attach(event, rb);
6649
6650 perf_event_update_time(event);
6651 perf_event_init_userpage(event);
6652 perf_event_update_userpage(event);
6653 } else {
6654 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6655 event->attr.aux_watermark, flags);
6656 if (!ret)
6657 rb->aux_mmap_locked = extra;
6658 }
6659
6660 unlock:
6661 if (!ret) {
6662 atomic_long_add(user_extra, &user->locked_vm);
6663 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6664
6665 atomic_inc(&event->mmap_count);
6666 } else if (rb) {
6667 atomic_dec(&rb->mmap_count);
6668 }
6669 aux_unlock:
6670 mutex_unlock(&event->mmap_mutex);
6671
6672 /*
6673 * Since pinned accounting is per vm we cannot allow fork() to copy our
6674 * vma.
6675 */
6676 vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP);
6677 vma->vm_ops = &perf_mmap_vmops;
6678
6679 if (event->pmu->event_mapped)
6680 event->pmu->event_mapped(event, vma->vm_mm);
6681
6682 return ret;
6683 }
6684
perf_fasync(int fd,struct file * filp,int on)6685 static int perf_fasync(int fd, struct file *filp, int on)
6686 {
6687 struct inode *inode = file_inode(filp);
6688 struct perf_event *event = filp->private_data;
6689 int retval;
6690
6691 inode_lock(inode);
6692 retval = fasync_helper(fd, filp, on, &event->fasync);
6693 inode_unlock(inode);
6694
6695 if (retval < 0)
6696 return retval;
6697
6698 return 0;
6699 }
6700
6701 static const struct file_operations perf_fops = {
6702 .llseek = no_llseek,
6703 .release = perf_release,
6704 .read = perf_read,
6705 .poll = perf_poll,
6706 .unlocked_ioctl = perf_ioctl,
6707 .compat_ioctl = perf_compat_ioctl,
6708 .mmap = perf_mmap,
6709 .fasync = perf_fasync,
6710 };
6711
6712 /*
6713 * Perf event wakeup
6714 *
6715 * If there's data, ensure we set the poll() state and publish everything
6716 * to user-space before waking everybody up.
6717 */
6718
perf_event_wakeup(struct perf_event * event)6719 void perf_event_wakeup(struct perf_event *event)
6720 {
6721 ring_buffer_wakeup(event);
6722
6723 if (event->pending_kill) {
6724 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6725 event->pending_kill = 0;
6726 }
6727 }
6728
perf_sigtrap(struct perf_event * event)6729 static void perf_sigtrap(struct perf_event *event)
6730 {
6731 /*
6732 * We'd expect this to only occur if the irq_work is delayed and either
6733 * ctx->task or current has changed in the meantime. This can be the
6734 * case on architectures that do not implement arch_irq_work_raise().
6735 */
6736 if (WARN_ON_ONCE(event->ctx->task != current))
6737 return;
6738
6739 /*
6740 * Both perf_pending_task() and perf_pending_irq() can race with the
6741 * task exiting.
6742 */
6743 if (current->flags & PF_EXITING)
6744 return;
6745
6746 send_sig_perf((void __user *)event->pending_addr,
6747 event->orig_type, event->attr.sig_data);
6748 }
6749
6750 /*
6751 * Deliver the pending work in-event-context or follow the context.
6752 */
__perf_pending_irq(struct perf_event * event)6753 static void __perf_pending_irq(struct perf_event *event)
6754 {
6755 int cpu = READ_ONCE(event->oncpu);
6756
6757 /*
6758 * If the event isn't running; we done. event_sched_out() will have
6759 * taken care of things.
6760 */
6761 if (cpu < 0)
6762 return;
6763
6764 /*
6765 * Yay, we hit home and are in the context of the event.
6766 */
6767 if (cpu == smp_processor_id()) {
6768 if (event->pending_sigtrap) {
6769 event->pending_sigtrap = 0;
6770 perf_sigtrap(event);
6771 local_dec(&event->ctx->nr_pending);
6772 }
6773 if (event->pending_disable) {
6774 event->pending_disable = 0;
6775 perf_event_disable_local(event);
6776 }
6777 return;
6778 }
6779
6780 /*
6781 * CPU-A CPU-B
6782 *
6783 * perf_event_disable_inatomic()
6784 * @pending_disable = CPU-A;
6785 * irq_work_queue();
6786 *
6787 * sched-out
6788 * @pending_disable = -1;
6789 *
6790 * sched-in
6791 * perf_event_disable_inatomic()
6792 * @pending_disable = CPU-B;
6793 * irq_work_queue(); // FAILS
6794 *
6795 * irq_work_run()
6796 * perf_pending_irq()
6797 *
6798 * But the event runs on CPU-B and wants disabling there.
6799 */
6800 irq_work_queue_on(&event->pending_irq, cpu);
6801 }
6802
perf_pending_irq(struct irq_work * entry)6803 static void perf_pending_irq(struct irq_work *entry)
6804 {
6805 struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
6806 int rctx;
6807
6808 /*
6809 * If we 'fail' here, that's OK, it means recursion is already disabled
6810 * and we won't recurse 'further'.
6811 */
6812 rctx = perf_swevent_get_recursion_context();
6813
6814 /*
6815 * The wakeup isn't bound to the context of the event -- it can happen
6816 * irrespective of where the event is.
6817 */
6818 if (event->pending_wakeup) {
6819 event->pending_wakeup = 0;
6820 perf_event_wakeup(event);
6821 }
6822
6823 __perf_pending_irq(event);
6824
6825 if (rctx >= 0)
6826 perf_swevent_put_recursion_context(rctx);
6827 }
6828
perf_pending_task(struct callback_head * head)6829 static void perf_pending_task(struct callback_head *head)
6830 {
6831 struct perf_event *event = container_of(head, struct perf_event, pending_task);
6832 int rctx;
6833
6834 /*
6835 * If we 'fail' here, that's OK, it means recursion is already disabled
6836 * and we won't recurse 'further'.
6837 */
6838 preempt_disable_notrace();
6839 rctx = perf_swevent_get_recursion_context();
6840
6841 if (event->pending_work) {
6842 event->pending_work = 0;
6843 perf_sigtrap(event);
6844 local_dec(&event->ctx->nr_pending);
6845 }
6846
6847 if (rctx >= 0)
6848 perf_swevent_put_recursion_context(rctx);
6849 preempt_enable_notrace();
6850
6851 put_event(event);
6852 }
6853
6854 #ifdef CONFIG_GUEST_PERF_EVENTS
6855 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6856
6857 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6858 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6859 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6860
perf_register_guest_info_callbacks(struct perf_guest_info_callbacks * cbs)6861 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6862 {
6863 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6864 return;
6865
6866 rcu_assign_pointer(perf_guest_cbs, cbs);
6867 static_call_update(__perf_guest_state, cbs->state);
6868 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6869
6870 /* Implementing ->handle_intel_pt_intr is optional. */
6871 if (cbs->handle_intel_pt_intr)
6872 static_call_update(__perf_guest_handle_intel_pt_intr,
6873 cbs->handle_intel_pt_intr);
6874 }
6875 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6876
perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks * cbs)6877 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6878 {
6879 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6880 return;
6881
6882 rcu_assign_pointer(perf_guest_cbs, NULL);
6883 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6884 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6885 static_call_update(__perf_guest_handle_intel_pt_intr,
6886 (void *)&__static_call_return0);
6887 synchronize_rcu();
6888 }
6889 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6890 #endif
6891
6892 static void
perf_output_sample_regs(struct perf_output_handle * handle,struct pt_regs * regs,u64 mask)6893 perf_output_sample_regs(struct perf_output_handle *handle,
6894 struct pt_regs *regs, u64 mask)
6895 {
6896 int bit;
6897 DECLARE_BITMAP(_mask, 64);
6898
6899 bitmap_from_u64(_mask, mask);
6900 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6901 u64 val;
6902
6903 val = perf_reg_value(regs, bit);
6904 perf_output_put(handle, val);
6905 }
6906 }
6907
perf_sample_regs_user(struct perf_regs * regs_user,struct pt_regs * regs)6908 static void perf_sample_regs_user(struct perf_regs *regs_user,
6909 struct pt_regs *regs)
6910 {
6911 if (user_mode(regs)) {
6912 regs_user->abi = perf_reg_abi(current);
6913 regs_user->regs = regs;
6914 } else if (!(current->flags & PF_KTHREAD)) {
6915 perf_get_regs_user(regs_user, regs);
6916 } else {
6917 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6918 regs_user->regs = NULL;
6919 }
6920 }
6921
perf_sample_regs_intr(struct perf_regs * regs_intr,struct pt_regs * regs)6922 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6923 struct pt_regs *regs)
6924 {
6925 regs_intr->regs = regs;
6926 regs_intr->abi = perf_reg_abi(current);
6927 }
6928
6929
6930 /*
6931 * Get remaining task size from user stack pointer.
6932 *
6933 * It'd be better to take stack vma map and limit this more
6934 * precisely, but there's no way to get it safely under interrupt,
6935 * so using TASK_SIZE as limit.
6936 */
perf_ustack_task_size(struct pt_regs * regs)6937 static u64 perf_ustack_task_size(struct pt_regs *regs)
6938 {
6939 unsigned long addr = perf_user_stack_pointer(regs);
6940
6941 if (!addr || addr >= TASK_SIZE)
6942 return 0;
6943
6944 return TASK_SIZE - addr;
6945 }
6946
6947 static u16
perf_sample_ustack_size(u16 stack_size,u16 header_size,struct pt_regs * regs)6948 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6949 struct pt_regs *regs)
6950 {
6951 u64 task_size;
6952
6953 /* No regs, no stack pointer, no dump. */
6954 if (!regs)
6955 return 0;
6956
6957 /*
6958 * Check if we fit in with the requested stack size into the:
6959 * - TASK_SIZE
6960 * If we don't, we limit the size to the TASK_SIZE.
6961 *
6962 * - remaining sample size
6963 * If we don't, we customize the stack size to
6964 * fit in to the remaining sample size.
6965 */
6966
6967 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6968 stack_size = min(stack_size, (u16) task_size);
6969
6970 /* Current header size plus static size and dynamic size. */
6971 header_size += 2 * sizeof(u64);
6972
6973 /* Do we fit in with the current stack dump size? */
6974 if ((u16) (header_size + stack_size) < header_size) {
6975 /*
6976 * If we overflow the maximum size for the sample,
6977 * we customize the stack dump size to fit in.
6978 */
6979 stack_size = USHRT_MAX - header_size - sizeof(u64);
6980 stack_size = round_up(stack_size, sizeof(u64));
6981 }
6982
6983 return stack_size;
6984 }
6985
6986 static void
perf_output_sample_ustack(struct perf_output_handle * handle,u64 dump_size,struct pt_regs * regs)6987 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6988 struct pt_regs *regs)
6989 {
6990 /* Case of a kernel thread, nothing to dump */
6991 if (!regs) {
6992 u64 size = 0;
6993 perf_output_put(handle, size);
6994 } else {
6995 unsigned long sp;
6996 unsigned int rem;
6997 u64 dyn_size;
6998
6999 /*
7000 * We dump:
7001 * static size
7002 * - the size requested by user or the best one we can fit
7003 * in to the sample max size
7004 * data
7005 * - user stack dump data
7006 * dynamic size
7007 * - the actual dumped size
7008 */
7009
7010 /* Static size. */
7011 perf_output_put(handle, dump_size);
7012
7013 /* Data. */
7014 sp = perf_user_stack_pointer(regs);
7015 rem = __output_copy_user(handle, (void *) sp, dump_size);
7016 dyn_size = dump_size - rem;
7017
7018 perf_output_skip(handle, rem);
7019
7020 /* Dynamic size. */
7021 perf_output_put(handle, dyn_size);
7022 }
7023 }
7024
perf_prepare_sample_aux(struct perf_event * event,struct perf_sample_data * data,size_t size)7025 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
7026 struct perf_sample_data *data,
7027 size_t size)
7028 {
7029 struct perf_event *sampler = event->aux_event;
7030 struct perf_buffer *rb;
7031
7032 data->aux_size = 0;
7033
7034 if (!sampler)
7035 goto out;
7036
7037 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
7038 goto out;
7039
7040 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
7041 goto out;
7042
7043 rb = ring_buffer_get(sampler);
7044 if (!rb)
7045 goto out;
7046
7047 /*
7048 * If this is an NMI hit inside sampling code, don't take
7049 * the sample. See also perf_aux_sample_output().
7050 */
7051 if (READ_ONCE(rb->aux_in_sampling)) {
7052 data->aux_size = 0;
7053 } else {
7054 size = min_t(size_t, size, perf_aux_size(rb));
7055 data->aux_size = ALIGN(size, sizeof(u64));
7056 }
7057 ring_buffer_put(rb);
7058
7059 out:
7060 return data->aux_size;
7061 }
7062
perf_pmu_snapshot_aux(struct perf_buffer * rb,struct perf_event * event,struct perf_output_handle * handle,unsigned long size)7063 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
7064 struct perf_event *event,
7065 struct perf_output_handle *handle,
7066 unsigned long size)
7067 {
7068 unsigned long flags;
7069 long ret;
7070
7071 /*
7072 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
7073 * paths. If we start calling them in NMI context, they may race with
7074 * the IRQ ones, that is, for example, re-starting an event that's just
7075 * been stopped, which is why we're using a separate callback that
7076 * doesn't change the event state.
7077 *
7078 * IRQs need to be disabled to prevent IPIs from racing with us.
7079 */
7080 local_irq_save(flags);
7081 /*
7082 * Guard against NMI hits inside the critical section;
7083 * see also perf_prepare_sample_aux().
7084 */
7085 WRITE_ONCE(rb->aux_in_sampling, 1);
7086 barrier();
7087
7088 ret = event->pmu->snapshot_aux(event, handle, size);
7089
7090 barrier();
7091 WRITE_ONCE(rb->aux_in_sampling, 0);
7092 local_irq_restore(flags);
7093
7094 return ret;
7095 }
7096
perf_aux_sample_output(struct perf_event * event,struct perf_output_handle * handle,struct perf_sample_data * data)7097 static void perf_aux_sample_output(struct perf_event *event,
7098 struct perf_output_handle *handle,
7099 struct perf_sample_data *data)
7100 {
7101 struct perf_event *sampler = event->aux_event;
7102 struct perf_buffer *rb;
7103 unsigned long pad;
7104 long size;
7105
7106 if (WARN_ON_ONCE(!sampler || !data->aux_size))
7107 return;
7108
7109 rb = ring_buffer_get(sampler);
7110 if (!rb)
7111 return;
7112
7113 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
7114
7115 /*
7116 * An error here means that perf_output_copy() failed (returned a
7117 * non-zero surplus that it didn't copy), which in its current
7118 * enlightened implementation is not possible. If that changes, we'd
7119 * like to know.
7120 */
7121 if (WARN_ON_ONCE(size < 0))
7122 goto out_put;
7123
7124 /*
7125 * The pad comes from ALIGN()ing data->aux_size up to u64 in
7126 * perf_prepare_sample_aux(), so should not be more than that.
7127 */
7128 pad = data->aux_size - size;
7129 if (WARN_ON_ONCE(pad >= sizeof(u64)))
7130 pad = 8;
7131
7132 if (pad) {
7133 u64 zero = 0;
7134 perf_output_copy(handle, &zero, pad);
7135 }
7136
7137 out_put:
7138 ring_buffer_put(rb);
7139 }
7140
7141 /*
7142 * A set of common sample data types saved even for non-sample records
7143 * when event->attr.sample_id_all is set.
7144 */
7145 #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
7146 PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \
7147 PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER)
7148
__perf_event_header__init_id(struct perf_sample_data * data,struct perf_event * event,u64 sample_type)7149 static void __perf_event_header__init_id(struct perf_sample_data *data,
7150 struct perf_event *event,
7151 u64 sample_type)
7152 {
7153 data->type = event->attr.sample_type;
7154 data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL;
7155
7156 if (sample_type & PERF_SAMPLE_TID) {
7157 /* namespace issues */
7158 data->tid_entry.pid = perf_event_pid(event, current);
7159 data->tid_entry.tid = perf_event_tid(event, current);
7160 }
7161
7162 if (sample_type & PERF_SAMPLE_TIME)
7163 data->time = perf_event_clock(event);
7164
7165 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
7166 data->id = primary_event_id(event);
7167
7168 if (sample_type & PERF_SAMPLE_STREAM_ID)
7169 data->stream_id = event->id;
7170
7171 if (sample_type & PERF_SAMPLE_CPU) {
7172 data->cpu_entry.cpu = raw_smp_processor_id();
7173 data->cpu_entry.reserved = 0;
7174 }
7175 }
7176
perf_event_header__init_id(struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event)7177 void perf_event_header__init_id(struct perf_event_header *header,
7178 struct perf_sample_data *data,
7179 struct perf_event *event)
7180 {
7181 if (event->attr.sample_id_all) {
7182 header->size += event->id_header_size;
7183 __perf_event_header__init_id(data, event, event->attr.sample_type);
7184 }
7185 }
7186
__perf_event__output_id_sample(struct perf_output_handle * handle,struct perf_sample_data * data)7187 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
7188 struct perf_sample_data *data)
7189 {
7190 u64 sample_type = data->type;
7191
7192 if (sample_type & PERF_SAMPLE_TID)
7193 perf_output_put(handle, data->tid_entry);
7194
7195 if (sample_type & PERF_SAMPLE_TIME)
7196 perf_output_put(handle, data->time);
7197
7198 if (sample_type & PERF_SAMPLE_ID)
7199 perf_output_put(handle, data->id);
7200
7201 if (sample_type & PERF_SAMPLE_STREAM_ID)
7202 perf_output_put(handle, data->stream_id);
7203
7204 if (sample_type & PERF_SAMPLE_CPU)
7205 perf_output_put(handle, data->cpu_entry);
7206
7207 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7208 perf_output_put(handle, data->id);
7209 }
7210
perf_event__output_id_sample(struct perf_event * event,struct perf_output_handle * handle,struct perf_sample_data * sample)7211 void perf_event__output_id_sample(struct perf_event *event,
7212 struct perf_output_handle *handle,
7213 struct perf_sample_data *sample)
7214 {
7215 if (event->attr.sample_id_all)
7216 __perf_event__output_id_sample(handle, sample);
7217 }
7218
perf_output_read_one(struct perf_output_handle * handle,struct perf_event * event,u64 enabled,u64 running)7219 static void perf_output_read_one(struct perf_output_handle *handle,
7220 struct perf_event *event,
7221 u64 enabled, u64 running)
7222 {
7223 u64 read_format = event->attr.read_format;
7224 u64 values[5];
7225 int n = 0;
7226
7227 values[n++] = perf_event_count(event);
7228 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
7229 values[n++] = enabled +
7230 atomic64_read(&event->child_total_time_enabled);
7231 }
7232 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
7233 values[n++] = running +
7234 atomic64_read(&event->child_total_time_running);
7235 }
7236 if (read_format & PERF_FORMAT_ID)
7237 values[n++] = primary_event_id(event);
7238 if (read_format & PERF_FORMAT_LOST)
7239 values[n++] = atomic64_read(&event->lost_samples);
7240
7241 __output_copy(handle, values, n * sizeof(u64));
7242 }
7243
perf_output_read_group(struct perf_output_handle * handle,struct perf_event * event,u64 enabled,u64 running)7244 static void perf_output_read_group(struct perf_output_handle *handle,
7245 struct perf_event *event,
7246 u64 enabled, u64 running)
7247 {
7248 struct perf_event *leader = event->group_leader, *sub;
7249 u64 read_format = event->attr.read_format;
7250 unsigned long flags;
7251 u64 values[6];
7252 int n = 0;
7253
7254 /*
7255 * Disabling interrupts avoids all counter scheduling
7256 * (context switches, timer based rotation and IPIs).
7257 */
7258 local_irq_save(flags);
7259
7260 values[n++] = 1 + leader->nr_siblings;
7261
7262 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7263 values[n++] = enabled;
7264
7265 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7266 values[n++] = running;
7267
7268 if ((leader != event) &&
7269 (leader->state == PERF_EVENT_STATE_ACTIVE))
7270 leader->pmu->read(leader);
7271
7272 values[n++] = perf_event_count(leader);
7273 if (read_format & PERF_FORMAT_ID)
7274 values[n++] = primary_event_id(leader);
7275 if (read_format & PERF_FORMAT_LOST)
7276 values[n++] = atomic64_read(&leader->lost_samples);
7277
7278 __output_copy(handle, values, n * sizeof(u64));
7279
7280 for_each_sibling_event(sub, leader) {
7281 n = 0;
7282
7283 if ((sub != event) &&
7284 (sub->state == PERF_EVENT_STATE_ACTIVE))
7285 sub->pmu->read(sub);
7286
7287 values[n++] = perf_event_count(sub);
7288 if (read_format & PERF_FORMAT_ID)
7289 values[n++] = primary_event_id(sub);
7290 if (read_format & PERF_FORMAT_LOST)
7291 values[n++] = atomic64_read(&sub->lost_samples);
7292
7293 __output_copy(handle, values, n * sizeof(u64));
7294 }
7295
7296 local_irq_restore(flags);
7297 }
7298
7299 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7300 PERF_FORMAT_TOTAL_TIME_RUNNING)
7301
7302 /*
7303 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7304 *
7305 * The problem is that its both hard and excessively expensive to iterate the
7306 * child list, not to mention that its impossible to IPI the children running
7307 * on another CPU, from interrupt/NMI context.
7308 */
perf_output_read(struct perf_output_handle * handle,struct perf_event * event)7309 static void perf_output_read(struct perf_output_handle *handle,
7310 struct perf_event *event)
7311 {
7312 u64 enabled = 0, running = 0, now;
7313 u64 read_format = event->attr.read_format;
7314
7315 /*
7316 * compute total_time_enabled, total_time_running
7317 * based on snapshot values taken when the event
7318 * was last scheduled in.
7319 *
7320 * we cannot simply called update_context_time()
7321 * because of locking issue as we are called in
7322 * NMI context
7323 */
7324 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7325 calc_timer_values(event, &now, &enabled, &running);
7326
7327 if (event->attr.read_format & PERF_FORMAT_GROUP)
7328 perf_output_read_group(handle, event, enabled, running);
7329 else
7330 perf_output_read_one(handle, event, enabled, running);
7331 }
7332
perf_output_sample(struct perf_output_handle * handle,struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event)7333 void perf_output_sample(struct perf_output_handle *handle,
7334 struct perf_event_header *header,
7335 struct perf_sample_data *data,
7336 struct perf_event *event)
7337 {
7338 u64 sample_type = data->type;
7339
7340 perf_output_put(handle, *header);
7341
7342 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7343 perf_output_put(handle, data->id);
7344
7345 if (sample_type & PERF_SAMPLE_IP)
7346 perf_output_put(handle, data->ip);
7347
7348 if (sample_type & PERF_SAMPLE_TID)
7349 perf_output_put(handle, data->tid_entry);
7350
7351 if (sample_type & PERF_SAMPLE_TIME)
7352 perf_output_put(handle, data->time);
7353
7354 if (sample_type & PERF_SAMPLE_ADDR)
7355 perf_output_put(handle, data->addr);
7356
7357 if (sample_type & PERF_SAMPLE_ID)
7358 perf_output_put(handle, data->id);
7359
7360 if (sample_type & PERF_SAMPLE_STREAM_ID)
7361 perf_output_put(handle, data->stream_id);
7362
7363 if (sample_type & PERF_SAMPLE_CPU)
7364 perf_output_put(handle, data->cpu_entry);
7365
7366 if (sample_type & PERF_SAMPLE_PERIOD)
7367 perf_output_put(handle, data->period);
7368
7369 if (sample_type & PERF_SAMPLE_READ)
7370 perf_output_read(handle, event);
7371
7372 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7373 int size = 1;
7374
7375 size += data->callchain->nr;
7376 size *= sizeof(u64);
7377 __output_copy(handle, data->callchain, size);
7378 }
7379
7380 if (sample_type & PERF_SAMPLE_RAW) {
7381 struct perf_raw_record *raw = data->raw;
7382
7383 if (raw) {
7384 struct perf_raw_frag *frag = &raw->frag;
7385
7386 perf_output_put(handle, raw->size);
7387 do {
7388 if (frag->copy) {
7389 __output_custom(handle, frag->copy,
7390 frag->data, frag->size);
7391 } else {
7392 __output_copy(handle, frag->data,
7393 frag->size);
7394 }
7395 if (perf_raw_frag_last(frag))
7396 break;
7397 frag = frag->next;
7398 } while (1);
7399 if (frag->pad)
7400 __output_skip(handle, NULL, frag->pad);
7401 } else {
7402 struct {
7403 u32 size;
7404 u32 data;
7405 } raw = {
7406 .size = sizeof(u32),
7407 .data = 0,
7408 };
7409 perf_output_put(handle, raw);
7410 }
7411 }
7412
7413 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7414 if (data->br_stack) {
7415 size_t size;
7416
7417 size = data->br_stack->nr
7418 * sizeof(struct perf_branch_entry);
7419
7420 perf_output_put(handle, data->br_stack->nr);
7421 if (branch_sample_hw_index(event))
7422 perf_output_put(handle, data->br_stack->hw_idx);
7423 perf_output_copy(handle, data->br_stack->entries, size);
7424 /*
7425 * Add the extension space which is appended
7426 * right after the struct perf_branch_stack.
7427 */
7428 if (data->br_stack_cntr) {
7429 size = data->br_stack->nr * sizeof(u64);
7430 perf_output_copy(handle, data->br_stack_cntr, size);
7431 }
7432 } else {
7433 /*
7434 * we always store at least the value of nr
7435 */
7436 u64 nr = 0;
7437 perf_output_put(handle, nr);
7438 }
7439 }
7440
7441 if (sample_type & PERF_SAMPLE_REGS_USER) {
7442 u64 abi = data->regs_user.abi;
7443
7444 /*
7445 * If there are no regs to dump, notice it through
7446 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7447 */
7448 perf_output_put(handle, abi);
7449
7450 if (abi) {
7451 u64 mask = event->attr.sample_regs_user;
7452 perf_output_sample_regs(handle,
7453 data->regs_user.regs,
7454 mask);
7455 }
7456 }
7457
7458 if (sample_type & PERF_SAMPLE_STACK_USER) {
7459 perf_output_sample_ustack(handle,
7460 data->stack_user_size,
7461 data->regs_user.regs);
7462 }
7463
7464 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7465 perf_output_put(handle, data->weight.full);
7466
7467 if (sample_type & PERF_SAMPLE_DATA_SRC)
7468 perf_output_put(handle, data->data_src.val);
7469
7470 if (sample_type & PERF_SAMPLE_TRANSACTION)
7471 perf_output_put(handle, data->txn);
7472
7473 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7474 u64 abi = data->regs_intr.abi;
7475 /*
7476 * If there are no regs to dump, notice it through
7477 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7478 */
7479 perf_output_put(handle, abi);
7480
7481 if (abi) {
7482 u64 mask = event->attr.sample_regs_intr;
7483
7484 perf_output_sample_regs(handle,
7485 data->regs_intr.regs,
7486 mask);
7487 }
7488 }
7489
7490 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7491 perf_output_put(handle, data->phys_addr);
7492
7493 if (sample_type & PERF_SAMPLE_CGROUP)
7494 perf_output_put(handle, data->cgroup);
7495
7496 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7497 perf_output_put(handle, data->data_page_size);
7498
7499 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7500 perf_output_put(handle, data->code_page_size);
7501
7502 if (sample_type & PERF_SAMPLE_AUX) {
7503 perf_output_put(handle, data->aux_size);
7504
7505 if (data->aux_size)
7506 perf_aux_sample_output(event, handle, data);
7507 }
7508
7509 if (!event->attr.watermark) {
7510 int wakeup_events = event->attr.wakeup_events;
7511
7512 if (wakeup_events) {
7513 struct perf_buffer *rb = handle->rb;
7514 int events = local_inc_return(&rb->events);
7515
7516 if (events >= wakeup_events) {
7517 local_sub(wakeup_events, &rb->events);
7518 local_inc(&rb->wakeup);
7519 }
7520 }
7521 }
7522 }
7523
perf_virt_to_phys(u64 virt)7524 static u64 perf_virt_to_phys(u64 virt)
7525 {
7526 u64 phys_addr = 0;
7527
7528 if (!virt)
7529 return 0;
7530
7531 if (virt >= TASK_SIZE) {
7532 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7533 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7534 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7535 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7536 } else {
7537 /*
7538 * Walking the pages tables for user address.
7539 * Interrupts are disabled, so it prevents any tear down
7540 * of the page tables.
7541 * Try IRQ-safe get_user_page_fast_only first.
7542 * If failed, leave phys_addr as 0.
7543 */
7544 if (current->mm != NULL) {
7545 struct page *p;
7546
7547 pagefault_disable();
7548 if (get_user_page_fast_only(virt, 0, &p)) {
7549 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7550 put_page(p);
7551 }
7552 pagefault_enable();
7553 }
7554 }
7555
7556 return phys_addr;
7557 }
7558
7559 /*
7560 * Return the pagetable size of a given virtual address.
7561 */
perf_get_pgtable_size(struct mm_struct * mm,unsigned long addr)7562 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7563 {
7564 u64 size = 0;
7565
7566 #ifdef CONFIG_HAVE_GUP_FAST
7567 pgd_t *pgdp, pgd;
7568 p4d_t *p4dp, p4d;
7569 pud_t *pudp, pud;
7570 pmd_t *pmdp, pmd;
7571 pte_t *ptep, pte;
7572
7573 pgdp = pgd_offset(mm, addr);
7574 pgd = READ_ONCE(*pgdp);
7575 if (pgd_none(pgd))
7576 return 0;
7577
7578 if (pgd_leaf(pgd))
7579 return pgd_leaf_size(pgd);
7580
7581 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7582 p4d = READ_ONCE(*p4dp);
7583 if (!p4d_present(p4d))
7584 return 0;
7585
7586 if (p4d_leaf(p4d))
7587 return p4d_leaf_size(p4d);
7588
7589 pudp = pud_offset_lockless(p4dp, p4d, addr);
7590 pud = READ_ONCE(*pudp);
7591 if (!pud_present(pud))
7592 return 0;
7593
7594 if (pud_leaf(pud))
7595 return pud_leaf_size(pud);
7596
7597 pmdp = pmd_offset_lockless(pudp, pud, addr);
7598 again:
7599 pmd = pmdp_get_lockless(pmdp);
7600 if (!pmd_present(pmd))
7601 return 0;
7602
7603 if (pmd_leaf(pmd))
7604 return pmd_leaf_size(pmd);
7605
7606 ptep = pte_offset_map(&pmd, addr);
7607 if (!ptep)
7608 goto again;
7609
7610 pte = ptep_get_lockless(ptep);
7611 if (pte_present(pte))
7612 size = pte_leaf_size(pte);
7613 pte_unmap(ptep);
7614 #endif /* CONFIG_HAVE_GUP_FAST */
7615
7616 return size;
7617 }
7618
perf_get_page_size(unsigned long addr)7619 static u64 perf_get_page_size(unsigned long addr)
7620 {
7621 struct mm_struct *mm;
7622 unsigned long flags;
7623 u64 size;
7624
7625 if (!addr)
7626 return 0;
7627
7628 /*
7629 * Software page-table walkers must disable IRQs,
7630 * which prevents any tear down of the page tables.
7631 */
7632 local_irq_save(flags);
7633
7634 mm = current->mm;
7635 if (!mm) {
7636 /*
7637 * For kernel threads and the like, use init_mm so that
7638 * we can find kernel memory.
7639 */
7640 mm = &init_mm;
7641 }
7642
7643 size = perf_get_pgtable_size(mm, addr);
7644
7645 local_irq_restore(flags);
7646
7647 return size;
7648 }
7649
7650 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7651
7652 struct perf_callchain_entry *
perf_callchain(struct perf_event * event,struct pt_regs * regs)7653 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7654 {
7655 bool kernel = !event->attr.exclude_callchain_kernel;
7656 bool user = !event->attr.exclude_callchain_user;
7657 /* Disallow cross-task user callchains. */
7658 bool crosstask = event->ctx->task && event->ctx->task != current;
7659 const u32 max_stack = event->attr.sample_max_stack;
7660 struct perf_callchain_entry *callchain;
7661
7662 if (!kernel && !user)
7663 return &__empty_callchain;
7664
7665 callchain = get_perf_callchain(regs, 0, kernel, user,
7666 max_stack, crosstask, true);
7667 return callchain ?: &__empty_callchain;
7668 }
7669
__cond_set(u64 flags,u64 s,u64 d)7670 static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d)
7671 {
7672 return d * !!(flags & s);
7673 }
7674
perf_prepare_sample(struct perf_sample_data * data,struct perf_event * event,struct pt_regs * regs)7675 void perf_prepare_sample(struct perf_sample_data *data,
7676 struct perf_event *event,
7677 struct pt_regs *regs)
7678 {
7679 u64 sample_type = event->attr.sample_type;
7680 u64 filtered_sample_type;
7681
7682 /*
7683 * Add the sample flags that are dependent to others. And clear the
7684 * sample flags that have already been done by the PMU driver.
7685 */
7686 filtered_sample_type = sample_type;
7687 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE,
7688 PERF_SAMPLE_IP);
7689 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE |
7690 PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR);
7691 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER,
7692 PERF_SAMPLE_REGS_USER);
7693 filtered_sample_type &= ~data->sample_flags;
7694
7695 if (filtered_sample_type == 0) {
7696 /* Make sure it has the correct data->type for output */
7697 data->type = event->attr.sample_type;
7698 return;
7699 }
7700
7701 __perf_event_header__init_id(data, event, filtered_sample_type);
7702
7703 if (filtered_sample_type & PERF_SAMPLE_IP) {
7704 data->ip = perf_instruction_pointer(regs);
7705 data->sample_flags |= PERF_SAMPLE_IP;
7706 }
7707
7708 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
7709 perf_sample_save_callchain(data, event, regs);
7710
7711 if (filtered_sample_type & PERF_SAMPLE_RAW) {
7712 data->raw = NULL;
7713 data->dyn_size += sizeof(u64);
7714 data->sample_flags |= PERF_SAMPLE_RAW;
7715 }
7716
7717 if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) {
7718 data->br_stack = NULL;
7719 data->dyn_size += sizeof(u64);
7720 data->sample_flags |= PERF_SAMPLE_BRANCH_STACK;
7721 }
7722
7723 if (filtered_sample_type & PERF_SAMPLE_REGS_USER)
7724 perf_sample_regs_user(&data->regs_user, regs);
7725
7726 /*
7727 * It cannot use the filtered_sample_type here as REGS_USER can be set
7728 * by STACK_USER (using __cond_set() above) and we don't want to update
7729 * the dyn_size if it's not requested by users.
7730 */
7731 if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) {
7732 /* regs dump ABI info */
7733 int size = sizeof(u64);
7734
7735 if (data->regs_user.regs) {
7736 u64 mask = event->attr.sample_regs_user;
7737 size += hweight64(mask) * sizeof(u64);
7738 }
7739
7740 data->dyn_size += size;
7741 data->sample_flags |= PERF_SAMPLE_REGS_USER;
7742 }
7743
7744 if (filtered_sample_type & PERF_SAMPLE_STACK_USER) {
7745 /*
7746 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7747 * processed as the last one or have additional check added
7748 * in case new sample type is added, because we could eat
7749 * up the rest of the sample size.
7750 */
7751 u16 stack_size = event->attr.sample_stack_user;
7752 u16 header_size = perf_sample_data_size(data, event);
7753 u16 size = sizeof(u64);
7754
7755 stack_size = perf_sample_ustack_size(stack_size, header_size,
7756 data->regs_user.regs);
7757
7758 /*
7759 * If there is something to dump, add space for the dump
7760 * itself and for the field that tells the dynamic size,
7761 * which is how many have been actually dumped.
7762 */
7763 if (stack_size)
7764 size += sizeof(u64) + stack_size;
7765
7766 data->stack_user_size = stack_size;
7767 data->dyn_size += size;
7768 data->sample_flags |= PERF_SAMPLE_STACK_USER;
7769 }
7770
7771 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
7772 data->weight.full = 0;
7773 data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
7774 }
7775
7776 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) {
7777 data->data_src.val = PERF_MEM_NA;
7778 data->sample_flags |= PERF_SAMPLE_DATA_SRC;
7779 }
7780
7781 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) {
7782 data->txn = 0;
7783 data->sample_flags |= PERF_SAMPLE_TRANSACTION;
7784 }
7785
7786 if (filtered_sample_type & PERF_SAMPLE_ADDR) {
7787 data->addr = 0;
7788 data->sample_flags |= PERF_SAMPLE_ADDR;
7789 }
7790
7791 if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) {
7792 /* regs dump ABI info */
7793 int size = sizeof(u64);
7794
7795 perf_sample_regs_intr(&data->regs_intr, regs);
7796
7797 if (data->regs_intr.regs) {
7798 u64 mask = event->attr.sample_regs_intr;
7799
7800 size += hweight64(mask) * sizeof(u64);
7801 }
7802
7803 data->dyn_size += size;
7804 data->sample_flags |= PERF_SAMPLE_REGS_INTR;
7805 }
7806
7807 if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) {
7808 data->phys_addr = perf_virt_to_phys(data->addr);
7809 data->sample_flags |= PERF_SAMPLE_PHYS_ADDR;
7810 }
7811
7812 #ifdef CONFIG_CGROUP_PERF
7813 if (filtered_sample_type & PERF_SAMPLE_CGROUP) {
7814 struct cgroup *cgrp;
7815
7816 /* protected by RCU */
7817 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7818 data->cgroup = cgroup_id(cgrp);
7819 data->sample_flags |= PERF_SAMPLE_CGROUP;
7820 }
7821 #endif
7822
7823 /*
7824 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7825 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7826 * but the value will not dump to the userspace.
7827 */
7828 if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) {
7829 data->data_page_size = perf_get_page_size(data->addr);
7830 data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE;
7831 }
7832
7833 if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) {
7834 data->code_page_size = perf_get_page_size(data->ip);
7835 data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE;
7836 }
7837
7838 if (filtered_sample_type & PERF_SAMPLE_AUX) {
7839 u64 size;
7840 u16 header_size = perf_sample_data_size(data, event);
7841
7842 header_size += sizeof(u64); /* size */
7843
7844 /*
7845 * Given the 16bit nature of header::size, an AUX sample can
7846 * easily overflow it, what with all the preceding sample bits.
7847 * Make sure this doesn't happen by using up to U16_MAX bytes
7848 * per sample in total (rounded down to 8 byte boundary).
7849 */
7850 size = min_t(size_t, U16_MAX - header_size,
7851 event->attr.aux_sample_size);
7852 size = rounddown(size, 8);
7853 size = perf_prepare_sample_aux(event, data, size);
7854
7855 WARN_ON_ONCE(size + header_size > U16_MAX);
7856 data->dyn_size += size + sizeof(u64); /* size above */
7857 data->sample_flags |= PERF_SAMPLE_AUX;
7858 }
7859 }
7860
perf_prepare_header(struct perf_event_header * header,struct perf_sample_data * data,struct perf_event * event,struct pt_regs * regs)7861 void perf_prepare_header(struct perf_event_header *header,
7862 struct perf_sample_data *data,
7863 struct perf_event *event,
7864 struct pt_regs *regs)
7865 {
7866 header->type = PERF_RECORD_SAMPLE;
7867 header->size = perf_sample_data_size(data, event);
7868 header->misc = perf_misc_flags(regs);
7869
7870 /*
7871 * If you're adding more sample types here, you likely need to do
7872 * something about the overflowing header::size, like repurpose the
7873 * lowest 3 bits of size, which should be always zero at the moment.
7874 * This raises a more important question, do we really need 512k sized
7875 * samples and why, so good argumentation is in order for whatever you
7876 * do here next.
7877 */
7878 WARN_ON_ONCE(header->size & 7);
7879 }
7880
7881 static __always_inline int
__perf_event_output(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs,int (* output_begin)(struct perf_output_handle *,struct perf_sample_data *,struct perf_event *,unsigned int))7882 __perf_event_output(struct perf_event *event,
7883 struct perf_sample_data *data,
7884 struct pt_regs *regs,
7885 int (*output_begin)(struct perf_output_handle *,
7886 struct perf_sample_data *,
7887 struct perf_event *,
7888 unsigned int))
7889 {
7890 struct perf_output_handle handle;
7891 struct perf_event_header header;
7892 int err;
7893
7894 /* protect the callchain buffers */
7895 rcu_read_lock();
7896
7897 perf_prepare_sample(data, event, regs);
7898 perf_prepare_header(&header, data, event, regs);
7899
7900 err = output_begin(&handle, data, event, header.size);
7901 if (err)
7902 goto exit;
7903
7904 perf_output_sample(&handle, &header, data, event);
7905
7906 perf_output_end(&handle);
7907
7908 exit:
7909 rcu_read_unlock();
7910 return err;
7911 }
7912
7913 void
perf_event_output_forward(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7914 perf_event_output_forward(struct perf_event *event,
7915 struct perf_sample_data *data,
7916 struct pt_regs *regs)
7917 {
7918 __perf_event_output(event, data, regs, perf_output_begin_forward);
7919 }
7920
7921 void
perf_event_output_backward(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7922 perf_event_output_backward(struct perf_event *event,
7923 struct perf_sample_data *data,
7924 struct pt_regs *regs)
7925 {
7926 __perf_event_output(event, data, regs, perf_output_begin_backward);
7927 }
7928
7929 int
perf_event_output(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)7930 perf_event_output(struct perf_event *event,
7931 struct perf_sample_data *data,
7932 struct pt_regs *regs)
7933 {
7934 return __perf_event_output(event, data, regs, perf_output_begin);
7935 }
7936
7937 /*
7938 * read event_id
7939 */
7940
7941 struct perf_read_event {
7942 struct perf_event_header header;
7943
7944 u32 pid;
7945 u32 tid;
7946 };
7947
7948 static void
perf_event_read_event(struct perf_event * event,struct task_struct * task)7949 perf_event_read_event(struct perf_event *event,
7950 struct task_struct *task)
7951 {
7952 struct perf_output_handle handle;
7953 struct perf_sample_data sample;
7954 struct perf_read_event read_event = {
7955 .header = {
7956 .type = PERF_RECORD_READ,
7957 .misc = 0,
7958 .size = sizeof(read_event) + event->read_size,
7959 },
7960 .pid = perf_event_pid(event, task),
7961 .tid = perf_event_tid(event, task),
7962 };
7963 int ret;
7964
7965 perf_event_header__init_id(&read_event.header, &sample, event);
7966 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7967 if (ret)
7968 return;
7969
7970 perf_output_put(&handle, read_event);
7971 perf_output_read(&handle, event);
7972 perf_event__output_id_sample(event, &handle, &sample);
7973
7974 perf_output_end(&handle);
7975 }
7976
7977 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7978
7979 static void
perf_iterate_ctx(struct perf_event_context * ctx,perf_iterate_f output,void * data,bool all)7980 perf_iterate_ctx(struct perf_event_context *ctx,
7981 perf_iterate_f output,
7982 void *data, bool all)
7983 {
7984 struct perf_event *event;
7985
7986 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7987 if (!all) {
7988 if (event->state < PERF_EVENT_STATE_INACTIVE)
7989 continue;
7990 if (!event_filter_match(event))
7991 continue;
7992 }
7993
7994 output(event, data);
7995 }
7996 }
7997
perf_iterate_sb_cpu(perf_iterate_f output,void * data)7998 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7999 {
8000 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
8001 struct perf_event *event;
8002
8003 list_for_each_entry_rcu(event, &pel->list, sb_list) {
8004 /*
8005 * Skip events that are not fully formed yet; ensure that
8006 * if we observe event->ctx, both event and ctx will be
8007 * complete enough. See perf_install_in_context().
8008 */
8009 if (!smp_load_acquire(&event->ctx))
8010 continue;
8011
8012 if (event->state < PERF_EVENT_STATE_INACTIVE)
8013 continue;
8014 if (!event_filter_match(event))
8015 continue;
8016 output(event, data);
8017 }
8018 }
8019
8020 /*
8021 * Iterate all events that need to receive side-band events.
8022 *
8023 * For new callers; ensure that account_pmu_sb_event() includes
8024 * your event, otherwise it might not get delivered.
8025 */
8026 static void
perf_iterate_sb(perf_iterate_f output,void * data,struct perf_event_context * task_ctx)8027 perf_iterate_sb(perf_iterate_f output, void *data,
8028 struct perf_event_context *task_ctx)
8029 {
8030 struct perf_event_context *ctx;
8031
8032 rcu_read_lock();
8033 preempt_disable();
8034
8035 /*
8036 * If we have task_ctx != NULL we only notify the task context itself.
8037 * The task_ctx is set only for EXIT events before releasing task
8038 * context.
8039 */
8040 if (task_ctx) {
8041 perf_iterate_ctx(task_ctx, output, data, false);
8042 goto done;
8043 }
8044
8045 perf_iterate_sb_cpu(output, data);
8046
8047 ctx = rcu_dereference(current->perf_event_ctxp);
8048 if (ctx)
8049 perf_iterate_ctx(ctx, output, data, false);
8050 done:
8051 preempt_enable();
8052 rcu_read_unlock();
8053 }
8054
8055 /*
8056 * Clear all file-based filters at exec, they'll have to be
8057 * re-instated when/if these objects are mmapped again.
8058 */
perf_event_addr_filters_exec(struct perf_event * event,void * data)8059 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
8060 {
8061 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8062 struct perf_addr_filter *filter;
8063 unsigned int restart = 0, count = 0;
8064 unsigned long flags;
8065
8066 if (!has_addr_filter(event))
8067 return;
8068
8069 raw_spin_lock_irqsave(&ifh->lock, flags);
8070 list_for_each_entry(filter, &ifh->list, entry) {
8071 if (filter->path.dentry) {
8072 event->addr_filter_ranges[count].start = 0;
8073 event->addr_filter_ranges[count].size = 0;
8074 restart++;
8075 }
8076
8077 count++;
8078 }
8079
8080 if (restart)
8081 event->addr_filters_gen++;
8082 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8083
8084 if (restart)
8085 perf_event_stop(event, 1);
8086 }
8087
perf_event_exec(void)8088 void perf_event_exec(void)
8089 {
8090 struct perf_event_context *ctx;
8091
8092 ctx = perf_pin_task_context(current);
8093 if (!ctx)
8094 return;
8095
8096 perf_event_enable_on_exec(ctx);
8097 perf_event_remove_on_exec(ctx);
8098 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
8099
8100 perf_unpin_context(ctx);
8101 put_ctx(ctx);
8102 }
8103
8104 struct remote_output {
8105 struct perf_buffer *rb;
8106 int err;
8107 };
8108
__perf_event_output_stop(struct perf_event * event,void * data)8109 static void __perf_event_output_stop(struct perf_event *event, void *data)
8110 {
8111 struct perf_event *parent = event->parent;
8112 struct remote_output *ro = data;
8113 struct perf_buffer *rb = ro->rb;
8114 struct stop_event_data sd = {
8115 .event = event,
8116 };
8117
8118 if (!has_aux(event))
8119 return;
8120
8121 if (!parent)
8122 parent = event;
8123
8124 /*
8125 * In case of inheritance, it will be the parent that links to the
8126 * ring-buffer, but it will be the child that's actually using it.
8127 *
8128 * We are using event::rb to determine if the event should be stopped,
8129 * however this may race with ring_buffer_attach() (through set_output),
8130 * which will make us skip the event that actually needs to be stopped.
8131 * So ring_buffer_attach() has to stop an aux event before re-assigning
8132 * its rb pointer.
8133 */
8134 if (rcu_dereference(parent->rb) == rb)
8135 ro->err = __perf_event_stop(&sd);
8136 }
8137
__perf_pmu_output_stop(void * info)8138 static int __perf_pmu_output_stop(void *info)
8139 {
8140 struct perf_event *event = info;
8141 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
8142 struct remote_output ro = {
8143 .rb = event->rb,
8144 };
8145
8146 rcu_read_lock();
8147 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
8148 if (cpuctx->task_ctx)
8149 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
8150 &ro, false);
8151 rcu_read_unlock();
8152
8153 return ro.err;
8154 }
8155
perf_pmu_output_stop(struct perf_event * event)8156 static void perf_pmu_output_stop(struct perf_event *event)
8157 {
8158 struct perf_event *iter;
8159 int err, cpu;
8160
8161 restart:
8162 rcu_read_lock();
8163 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
8164 /*
8165 * For per-CPU events, we need to make sure that neither they
8166 * nor their children are running; for cpu==-1 events it's
8167 * sufficient to stop the event itself if it's active, since
8168 * it can't have children.
8169 */
8170 cpu = iter->cpu;
8171 if (cpu == -1)
8172 cpu = READ_ONCE(iter->oncpu);
8173
8174 if (cpu == -1)
8175 continue;
8176
8177 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
8178 if (err == -EAGAIN) {
8179 rcu_read_unlock();
8180 goto restart;
8181 }
8182 }
8183 rcu_read_unlock();
8184 }
8185
8186 /*
8187 * task tracking -- fork/exit
8188 *
8189 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
8190 */
8191
8192 struct perf_task_event {
8193 struct task_struct *task;
8194 struct perf_event_context *task_ctx;
8195
8196 struct {
8197 struct perf_event_header header;
8198
8199 u32 pid;
8200 u32 ppid;
8201 u32 tid;
8202 u32 ptid;
8203 u64 time;
8204 } event_id;
8205 };
8206
perf_event_task_match(struct perf_event * event)8207 static int perf_event_task_match(struct perf_event *event)
8208 {
8209 return event->attr.comm || event->attr.mmap ||
8210 event->attr.mmap2 || event->attr.mmap_data ||
8211 event->attr.task;
8212 }
8213
perf_event_task_output(struct perf_event * event,void * data)8214 static void perf_event_task_output(struct perf_event *event,
8215 void *data)
8216 {
8217 struct perf_task_event *task_event = data;
8218 struct perf_output_handle handle;
8219 struct perf_sample_data sample;
8220 struct task_struct *task = task_event->task;
8221 int ret, size = task_event->event_id.header.size;
8222
8223 if (!perf_event_task_match(event))
8224 return;
8225
8226 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
8227
8228 ret = perf_output_begin(&handle, &sample, event,
8229 task_event->event_id.header.size);
8230 if (ret)
8231 goto out;
8232
8233 task_event->event_id.pid = perf_event_pid(event, task);
8234 task_event->event_id.tid = perf_event_tid(event, task);
8235
8236 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
8237 task_event->event_id.ppid = perf_event_pid(event,
8238 task->real_parent);
8239 task_event->event_id.ptid = perf_event_pid(event,
8240 task->real_parent);
8241 } else { /* PERF_RECORD_FORK */
8242 task_event->event_id.ppid = perf_event_pid(event, current);
8243 task_event->event_id.ptid = perf_event_tid(event, current);
8244 }
8245
8246 task_event->event_id.time = perf_event_clock(event);
8247
8248 perf_output_put(&handle, task_event->event_id);
8249
8250 perf_event__output_id_sample(event, &handle, &sample);
8251
8252 perf_output_end(&handle);
8253 out:
8254 task_event->event_id.header.size = size;
8255 }
8256
perf_event_task(struct task_struct * task,struct perf_event_context * task_ctx,int new)8257 static void perf_event_task(struct task_struct *task,
8258 struct perf_event_context *task_ctx,
8259 int new)
8260 {
8261 struct perf_task_event task_event;
8262
8263 if (!atomic_read(&nr_comm_events) &&
8264 !atomic_read(&nr_mmap_events) &&
8265 !atomic_read(&nr_task_events))
8266 return;
8267
8268 task_event = (struct perf_task_event){
8269 .task = task,
8270 .task_ctx = task_ctx,
8271 .event_id = {
8272 .header = {
8273 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
8274 .misc = 0,
8275 .size = sizeof(task_event.event_id),
8276 },
8277 /* .pid */
8278 /* .ppid */
8279 /* .tid */
8280 /* .ptid */
8281 /* .time */
8282 },
8283 };
8284
8285 perf_iterate_sb(perf_event_task_output,
8286 &task_event,
8287 task_ctx);
8288 }
8289
perf_event_fork(struct task_struct * task)8290 void perf_event_fork(struct task_struct *task)
8291 {
8292 perf_event_task(task, NULL, 1);
8293 perf_event_namespaces(task);
8294 }
8295
8296 /*
8297 * comm tracking
8298 */
8299
8300 struct perf_comm_event {
8301 struct task_struct *task;
8302 char *comm;
8303 int comm_size;
8304
8305 struct {
8306 struct perf_event_header header;
8307
8308 u32 pid;
8309 u32 tid;
8310 } event_id;
8311 };
8312
perf_event_comm_match(struct perf_event * event)8313 static int perf_event_comm_match(struct perf_event *event)
8314 {
8315 return event->attr.comm;
8316 }
8317
perf_event_comm_output(struct perf_event * event,void * data)8318 static void perf_event_comm_output(struct perf_event *event,
8319 void *data)
8320 {
8321 struct perf_comm_event *comm_event = data;
8322 struct perf_output_handle handle;
8323 struct perf_sample_data sample;
8324 int size = comm_event->event_id.header.size;
8325 int ret;
8326
8327 if (!perf_event_comm_match(event))
8328 return;
8329
8330 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8331 ret = perf_output_begin(&handle, &sample, event,
8332 comm_event->event_id.header.size);
8333
8334 if (ret)
8335 goto out;
8336
8337 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8338 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8339
8340 perf_output_put(&handle, comm_event->event_id);
8341 __output_copy(&handle, comm_event->comm,
8342 comm_event->comm_size);
8343
8344 perf_event__output_id_sample(event, &handle, &sample);
8345
8346 perf_output_end(&handle);
8347 out:
8348 comm_event->event_id.header.size = size;
8349 }
8350
perf_event_comm_event(struct perf_comm_event * comm_event)8351 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8352 {
8353 char comm[TASK_COMM_LEN];
8354 unsigned int size;
8355
8356 memset(comm, 0, sizeof(comm));
8357 strscpy(comm, comm_event->task->comm, sizeof(comm));
8358 size = ALIGN(strlen(comm)+1, sizeof(u64));
8359
8360 comm_event->comm = comm;
8361 comm_event->comm_size = size;
8362
8363 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8364
8365 perf_iterate_sb(perf_event_comm_output,
8366 comm_event,
8367 NULL);
8368 }
8369
perf_event_comm(struct task_struct * task,bool exec)8370 void perf_event_comm(struct task_struct *task, bool exec)
8371 {
8372 struct perf_comm_event comm_event;
8373
8374 if (!atomic_read(&nr_comm_events))
8375 return;
8376
8377 comm_event = (struct perf_comm_event){
8378 .task = task,
8379 /* .comm */
8380 /* .comm_size */
8381 .event_id = {
8382 .header = {
8383 .type = PERF_RECORD_COMM,
8384 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8385 /* .size */
8386 },
8387 /* .pid */
8388 /* .tid */
8389 },
8390 };
8391
8392 perf_event_comm_event(&comm_event);
8393 }
8394
8395 /*
8396 * namespaces tracking
8397 */
8398
8399 struct perf_namespaces_event {
8400 struct task_struct *task;
8401
8402 struct {
8403 struct perf_event_header header;
8404
8405 u32 pid;
8406 u32 tid;
8407 u64 nr_namespaces;
8408 struct perf_ns_link_info link_info[NR_NAMESPACES];
8409 } event_id;
8410 };
8411
perf_event_namespaces_match(struct perf_event * event)8412 static int perf_event_namespaces_match(struct perf_event *event)
8413 {
8414 return event->attr.namespaces;
8415 }
8416
perf_event_namespaces_output(struct perf_event * event,void * data)8417 static void perf_event_namespaces_output(struct perf_event *event,
8418 void *data)
8419 {
8420 struct perf_namespaces_event *namespaces_event = data;
8421 struct perf_output_handle handle;
8422 struct perf_sample_data sample;
8423 u16 header_size = namespaces_event->event_id.header.size;
8424 int ret;
8425
8426 if (!perf_event_namespaces_match(event))
8427 return;
8428
8429 perf_event_header__init_id(&namespaces_event->event_id.header,
8430 &sample, event);
8431 ret = perf_output_begin(&handle, &sample, event,
8432 namespaces_event->event_id.header.size);
8433 if (ret)
8434 goto out;
8435
8436 namespaces_event->event_id.pid = perf_event_pid(event,
8437 namespaces_event->task);
8438 namespaces_event->event_id.tid = perf_event_tid(event,
8439 namespaces_event->task);
8440
8441 perf_output_put(&handle, namespaces_event->event_id);
8442
8443 perf_event__output_id_sample(event, &handle, &sample);
8444
8445 perf_output_end(&handle);
8446 out:
8447 namespaces_event->event_id.header.size = header_size;
8448 }
8449
perf_fill_ns_link_info(struct perf_ns_link_info * ns_link_info,struct task_struct * task,const struct proc_ns_operations * ns_ops)8450 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8451 struct task_struct *task,
8452 const struct proc_ns_operations *ns_ops)
8453 {
8454 struct path ns_path;
8455 struct inode *ns_inode;
8456 int error;
8457
8458 error = ns_get_path(&ns_path, task, ns_ops);
8459 if (!error) {
8460 ns_inode = ns_path.dentry->d_inode;
8461 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8462 ns_link_info->ino = ns_inode->i_ino;
8463 path_put(&ns_path);
8464 }
8465 }
8466
perf_event_namespaces(struct task_struct * task)8467 void perf_event_namespaces(struct task_struct *task)
8468 {
8469 struct perf_namespaces_event namespaces_event;
8470 struct perf_ns_link_info *ns_link_info;
8471
8472 if (!atomic_read(&nr_namespaces_events))
8473 return;
8474
8475 namespaces_event = (struct perf_namespaces_event){
8476 .task = task,
8477 .event_id = {
8478 .header = {
8479 .type = PERF_RECORD_NAMESPACES,
8480 .misc = 0,
8481 .size = sizeof(namespaces_event.event_id),
8482 },
8483 /* .pid */
8484 /* .tid */
8485 .nr_namespaces = NR_NAMESPACES,
8486 /* .link_info[NR_NAMESPACES] */
8487 },
8488 };
8489
8490 ns_link_info = namespaces_event.event_id.link_info;
8491
8492 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8493 task, &mntns_operations);
8494
8495 #ifdef CONFIG_USER_NS
8496 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8497 task, &userns_operations);
8498 #endif
8499 #ifdef CONFIG_NET_NS
8500 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8501 task, &netns_operations);
8502 #endif
8503 #ifdef CONFIG_UTS_NS
8504 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8505 task, &utsns_operations);
8506 #endif
8507 #ifdef CONFIG_IPC_NS
8508 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8509 task, &ipcns_operations);
8510 #endif
8511 #ifdef CONFIG_PID_NS
8512 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8513 task, &pidns_operations);
8514 #endif
8515 #ifdef CONFIG_CGROUPS
8516 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8517 task, &cgroupns_operations);
8518 #endif
8519
8520 perf_iterate_sb(perf_event_namespaces_output,
8521 &namespaces_event,
8522 NULL);
8523 }
8524
8525 /*
8526 * cgroup tracking
8527 */
8528 #ifdef CONFIG_CGROUP_PERF
8529
8530 struct perf_cgroup_event {
8531 char *path;
8532 int path_size;
8533 struct {
8534 struct perf_event_header header;
8535 u64 id;
8536 char path[];
8537 } event_id;
8538 };
8539
perf_event_cgroup_match(struct perf_event * event)8540 static int perf_event_cgroup_match(struct perf_event *event)
8541 {
8542 return event->attr.cgroup;
8543 }
8544
perf_event_cgroup_output(struct perf_event * event,void * data)8545 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8546 {
8547 struct perf_cgroup_event *cgroup_event = data;
8548 struct perf_output_handle handle;
8549 struct perf_sample_data sample;
8550 u16 header_size = cgroup_event->event_id.header.size;
8551 int ret;
8552
8553 if (!perf_event_cgroup_match(event))
8554 return;
8555
8556 perf_event_header__init_id(&cgroup_event->event_id.header,
8557 &sample, event);
8558 ret = perf_output_begin(&handle, &sample, event,
8559 cgroup_event->event_id.header.size);
8560 if (ret)
8561 goto out;
8562
8563 perf_output_put(&handle, cgroup_event->event_id);
8564 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8565
8566 perf_event__output_id_sample(event, &handle, &sample);
8567
8568 perf_output_end(&handle);
8569 out:
8570 cgroup_event->event_id.header.size = header_size;
8571 }
8572
perf_event_cgroup(struct cgroup * cgrp)8573 static void perf_event_cgroup(struct cgroup *cgrp)
8574 {
8575 struct perf_cgroup_event cgroup_event;
8576 char path_enomem[16] = "//enomem";
8577 char *pathname;
8578 size_t size;
8579
8580 if (!atomic_read(&nr_cgroup_events))
8581 return;
8582
8583 cgroup_event = (struct perf_cgroup_event){
8584 .event_id = {
8585 .header = {
8586 .type = PERF_RECORD_CGROUP,
8587 .misc = 0,
8588 .size = sizeof(cgroup_event.event_id),
8589 },
8590 .id = cgroup_id(cgrp),
8591 },
8592 };
8593
8594 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8595 if (pathname == NULL) {
8596 cgroup_event.path = path_enomem;
8597 } else {
8598 /* just to be sure to have enough space for alignment */
8599 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8600 cgroup_event.path = pathname;
8601 }
8602
8603 /*
8604 * Since our buffer works in 8 byte units we need to align our string
8605 * size to a multiple of 8. However, we must guarantee the tail end is
8606 * zero'd out to avoid leaking random bits to userspace.
8607 */
8608 size = strlen(cgroup_event.path) + 1;
8609 while (!IS_ALIGNED(size, sizeof(u64)))
8610 cgroup_event.path[size++] = '\0';
8611
8612 cgroup_event.event_id.header.size += size;
8613 cgroup_event.path_size = size;
8614
8615 perf_iterate_sb(perf_event_cgroup_output,
8616 &cgroup_event,
8617 NULL);
8618
8619 kfree(pathname);
8620 }
8621
8622 #endif
8623
8624 /*
8625 * mmap tracking
8626 */
8627
8628 struct perf_mmap_event {
8629 struct vm_area_struct *vma;
8630
8631 const char *file_name;
8632 int file_size;
8633 int maj, min;
8634 u64 ino;
8635 u64 ino_generation;
8636 u32 prot, flags;
8637 u8 build_id[BUILD_ID_SIZE_MAX];
8638 u32 build_id_size;
8639
8640 struct {
8641 struct perf_event_header header;
8642
8643 u32 pid;
8644 u32 tid;
8645 u64 start;
8646 u64 len;
8647 u64 pgoff;
8648 } event_id;
8649 };
8650
perf_event_mmap_match(struct perf_event * event,void * data)8651 static int perf_event_mmap_match(struct perf_event *event,
8652 void *data)
8653 {
8654 struct perf_mmap_event *mmap_event = data;
8655 struct vm_area_struct *vma = mmap_event->vma;
8656 int executable = vma->vm_flags & VM_EXEC;
8657
8658 return (!executable && event->attr.mmap_data) ||
8659 (executable && (event->attr.mmap || event->attr.mmap2));
8660 }
8661
perf_event_mmap_output(struct perf_event * event,void * data)8662 static void perf_event_mmap_output(struct perf_event *event,
8663 void *data)
8664 {
8665 struct perf_mmap_event *mmap_event = data;
8666 struct perf_output_handle handle;
8667 struct perf_sample_data sample;
8668 int size = mmap_event->event_id.header.size;
8669 u32 type = mmap_event->event_id.header.type;
8670 bool use_build_id;
8671 int ret;
8672
8673 if (!perf_event_mmap_match(event, data))
8674 return;
8675
8676 if (event->attr.mmap2) {
8677 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8678 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8679 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8680 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8681 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8682 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8683 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8684 }
8685
8686 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8687 ret = perf_output_begin(&handle, &sample, event,
8688 mmap_event->event_id.header.size);
8689 if (ret)
8690 goto out;
8691
8692 mmap_event->event_id.pid = perf_event_pid(event, current);
8693 mmap_event->event_id.tid = perf_event_tid(event, current);
8694
8695 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8696
8697 if (event->attr.mmap2 && use_build_id)
8698 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8699
8700 perf_output_put(&handle, mmap_event->event_id);
8701
8702 if (event->attr.mmap2) {
8703 if (use_build_id) {
8704 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8705
8706 __output_copy(&handle, size, 4);
8707 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8708 } else {
8709 perf_output_put(&handle, mmap_event->maj);
8710 perf_output_put(&handle, mmap_event->min);
8711 perf_output_put(&handle, mmap_event->ino);
8712 perf_output_put(&handle, mmap_event->ino_generation);
8713 }
8714 perf_output_put(&handle, mmap_event->prot);
8715 perf_output_put(&handle, mmap_event->flags);
8716 }
8717
8718 __output_copy(&handle, mmap_event->file_name,
8719 mmap_event->file_size);
8720
8721 perf_event__output_id_sample(event, &handle, &sample);
8722
8723 perf_output_end(&handle);
8724 out:
8725 mmap_event->event_id.header.size = size;
8726 mmap_event->event_id.header.type = type;
8727 }
8728
perf_event_mmap_event(struct perf_mmap_event * mmap_event)8729 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8730 {
8731 struct vm_area_struct *vma = mmap_event->vma;
8732 struct file *file = vma->vm_file;
8733 int maj = 0, min = 0;
8734 u64 ino = 0, gen = 0;
8735 u32 prot = 0, flags = 0;
8736 unsigned int size;
8737 char tmp[16];
8738 char *buf = NULL;
8739 char *name = NULL;
8740
8741 if (vma->vm_flags & VM_READ)
8742 prot |= PROT_READ;
8743 if (vma->vm_flags & VM_WRITE)
8744 prot |= PROT_WRITE;
8745 if (vma->vm_flags & VM_EXEC)
8746 prot |= PROT_EXEC;
8747
8748 if (vma->vm_flags & VM_MAYSHARE)
8749 flags = MAP_SHARED;
8750 else
8751 flags = MAP_PRIVATE;
8752
8753 if (vma->vm_flags & VM_LOCKED)
8754 flags |= MAP_LOCKED;
8755 if (is_vm_hugetlb_page(vma))
8756 flags |= MAP_HUGETLB;
8757
8758 if (file) {
8759 struct inode *inode;
8760 dev_t dev;
8761
8762 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8763 if (!buf) {
8764 name = "//enomem";
8765 goto cpy_name;
8766 }
8767 /*
8768 * d_path() works from the end of the rb backwards, so we
8769 * need to add enough zero bytes after the string to handle
8770 * the 64bit alignment we do later.
8771 */
8772 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8773 if (IS_ERR(name)) {
8774 name = "//toolong";
8775 goto cpy_name;
8776 }
8777 inode = file_inode(vma->vm_file);
8778 dev = inode->i_sb->s_dev;
8779 ino = inode->i_ino;
8780 gen = inode->i_generation;
8781 maj = MAJOR(dev);
8782 min = MINOR(dev);
8783
8784 goto got_name;
8785 } else {
8786 if (vma->vm_ops && vma->vm_ops->name)
8787 name = (char *) vma->vm_ops->name(vma);
8788 if (!name)
8789 name = (char *)arch_vma_name(vma);
8790 if (!name) {
8791 if (vma_is_initial_heap(vma))
8792 name = "[heap]";
8793 else if (vma_is_initial_stack(vma))
8794 name = "[stack]";
8795 else
8796 name = "//anon";
8797 }
8798 }
8799
8800 cpy_name:
8801 strscpy(tmp, name, sizeof(tmp));
8802 name = tmp;
8803 got_name:
8804 /*
8805 * Since our buffer works in 8 byte units we need to align our string
8806 * size to a multiple of 8. However, we must guarantee the tail end is
8807 * zero'd out to avoid leaking random bits to userspace.
8808 */
8809 size = strlen(name)+1;
8810 while (!IS_ALIGNED(size, sizeof(u64)))
8811 name[size++] = '\0';
8812
8813 mmap_event->file_name = name;
8814 mmap_event->file_size = size;
8815 mmap_event->maj = maj;
8816 mmap_event->min = min;
8817 mmap_event->ino = ino;
8818 mmap_event->ino_generation = gen;
8819 mmap_event->prot = prot;
8820 mmap_event->flags = flags;
8821
8822 if (!(vma->vm_flags & VM_EXEC))
8823 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8824
8825 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8826
8827 if (atomic_read(&nr_build_id_events))
8828 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8829
8830 perf_iterate_sb(perf_event_mmap_output,
8831 mmap_event,
8832 NULL);
8833
8834 kfree(buf);
8835 }
8836
8837 /*
8838 * Check whether inode and address range match filter criteria.
8839 */
perf_addr_filter_match(struct perf_addr_filter * filter,struct file * file,unsigned long offset,unsigned long size)8840 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8841 struct file *file, unsigned long offset,
8842 unsigned long size)
8843 {
8844 /* d_inode(NULL) won't be equal to any mapped user-space file */
8845 if (!filter->path.dentry)
8846 return false;
8847
8848 if (d_inode(filter->path.dentry) != file_inode(file))
8849 return false;
8850
8851 if (filter->offset > offset + size)
8852 return false;
8853
8854 if (filter->offset + filter->size < offset)
8855 return false;
8856
8857 return true;
8858 }
8859
perf_addr_filter_vma_adjust(struct perf_addr_filter * filter,struct vm_area_struct * vma,struct perf_addr_filter_range * fr)8860 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8861 struct vm_area_struct *vma,
8862 struct perf_addr_filter_range *fr)
8863 {
8864 unsigned long vma_size = vma->vm_end - vma->vm_start;
8865 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8866 struct file *file = vma->vm_file;
8867
8868 if (!perf_addr_filter_match(filter, file, off, vma_size))
8869 return false;
8870
8871 if (filter->offset < off) {
8872 fr->start = vma->vm_start;
8873 fr->size = min(vma_size, filter->size - (off - filter->offset));
8874 } else {
8875 fr->start = vma->vm_start + filter->offset - off;
8876 fr->size = min(vma->vm_end - fr->start, filter->size);
8877 }
8878
8879 return true;
8880 }
8881
__perf_addr_filters_adjust(struct perf_event * event,void * data)8882 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8883 {
8884 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8885 struct vm_area_struct *vma = data;
8886 struct perf_addr_filter *filter;
8887 unsigned int restart = 0, count = 0;
8888 unsigned long flags;
8889
8890 if (!has_addr_filter(event))
8891 return;
8892
8893 if (!vma->vm_file)
8894 return;
8895
8896 raw_spin_lock_irqsave(&ifh->lock, flags);
8897 list_for_each_entry(filter, &ifh->list, entry) {
8898 if (perf_addr_filter_vma_adjust(filter, vma,
8899 &event->addr_filter_ranges[count]))
8900 restart++;
8901
8902 count++;
8903 }
8904
8905 if (restart)
8906 event->addr_filters_gen++;
8907 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8908
8909 if (restart)
8910 perf_event_stop(event, 1);
8911 }
8912
8913 /*
8914 * Adjust all task's events' filters to the new vma
8915 */
perf_addr_filters_adjust(struct vm_area_struct * vma)8916 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8917 {
8918 struct perf_event_context *ctx;
8919
8920 /*
8921 * Data tracing isn't supported yet and as such there is no need
8922 * to keep track of anything that isn't related to executable code:
8923 */
8924 if (!(vma->vm_flags & VM_EXEC))
8925 return;
8926
8927 rcu_read_lock();
8928 ctx = rcu_dereference(current->perf_event_ctxp);
8929 if (ctx)
8930 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8931 rcu_read_unlock();
8932 }
8933
perf_event_mmap(struct vm_area_struct * vma)8934 void perf_event_mmap(struct vm_area_struct *vma)
8935 {
8936 struct perf_mmap_event mmap_event;
8937
8938 if (!atomic_read(&nr_mmap_events))
8939 return;
8940
8941 mmap_event = (struct perf_mmap_event){
8942 .vma = vma,
8943 /* .file_name */
8944 /* .file_size */
8945 .event_id = {
8946 .header = {
8947 .type = PERF_RECORD_MMAP,
8948 .misc = PERF_RECORD_MISC_USER,
8949 /* .size */
8950 },
8951 /* .pid */
8952 /* .tid */
8953 .start = vma->vm_start,
8954 .len = vma->vm_end - vma->vm_start,
8955 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8956 },
8957 /* .maj (attr_mmap2 only) */
8958 /* .min (attr_mmap2 only) */
8959 /* .ino (attr_mmap2 only) */
8960 /* .ino_generation (attr_mmap2 only) */
8961 /* .prot (attr_mmap2 only) */
8962 /* .flags (attr_mmap2 only) */
8963 };
8964
8965 perf_addr_filters_adjust(vma);
8966 perf_event_mmap_event(&mmap_event);
8967 }
8968
perf_event_aux_event(struct perf_event * event,unsigned long head,unsigned long size,u64 flags)8969 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8970 unsigned long size, u64 flags)
8971 {
8972 struct perf_output_handle handle;
8973 struct perf_sample_data sample;
8974 struct perf_aux_event {
8975 struct perf_event_header header;
8976 u64 offset;
8977 u64 size;
8978 u64 flags;
8979 } rec = {
8980 .header = {
8981 .type = PERF_RECORD_AUX,
8982 .misc = 0,
8983 .size = sizeof(rec),
8984 },
8985 .offset = head,
8986 .size = size,
8987 .flags = flags,
8988 };
8989 int ret;
8990
8991 perf_event_header__init_id(&rec.header, &sample, event);
8992 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8993
8994 if (ret)
8995 return;
8996
8997 perf_output_put(&handle, rec);
8998 perf_event__output_id_sample(event, &handle, &sample);
8999
9000 perf_output_end(&handle);
9001 }
9002
9003 /*
9004 * Lost/dropped samples logging
9005 */
perf_log_lost_samples(struct perf_event * event,u64 lost)9006 void perf_log_lost_samples(struct perf_event *event, u64 lost)
9007 {
9008 struct perf_output_handle handle;
9009 struct perf_sample_data sample;
9010 int ret;
9011
9012 struct {
9013 struct perf_event_header header;
9014 u64 lost;
9015 } lost_samples_event = {
9016 .header = {
9017 .type = PERF_RECORD_LOST_SAMPLES,
9018 .misc = 0,
9019 .size = sizeof(lost_samples_event),
9020 },
9021 .lost = lost,
9022 };
9023
9024 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
9025
9026 ret = perf_output_begin(&handle, &sample, event,
9027 lost_samples_event.header.size);
9028 if (ret)
9029 return;
9030
9031 perf_output_put(&handle, lost_samples_event);
9032 perf_event__output_id_sample(event, &handle, &sample);
9033 perf_output_end(&handle);
9034 }
9035
9036 /*
9037 * context_switch tracking
9038 */
9039
9040 struct perf_switch_event {
9041 struct task_struct *task;
9042 struct task_struct *next_prev;
9043
9044 struct {
9045 struct perf_event_header header;
9046 u32 next_prev_pid;
9047 u32 next_prev_tid;
9048 } event_id;
9049 };
9050
perf_event_switch_match(struct perf_event * event)9051 static int perf_event_switch_match(struct perf_event *event)
9052 {
9053 return event->attr.context_switch;
9054 }
9055
perf_event_switch_output(struct perf_event * event,void * data)9056 static void perf_event_switch_output(struct perf_event *event, void *data)
9057 {
9058 struct perf_switch_event *se = data;
9059 struct perf_output_handle handle;
9060 struct perf_sample_data sample;
9061 int ret;
9062
9063 if (!perf_event_switch_match(event))
9064 return;
9065
9066 /* Only CPU-wide events are allowed to see next/prev pid/tid */
9067 if (event->ctx->task) {
9068 se->event_id.header.type = PERF_RECORD_SWITCH;
9069 se->event_id.header.size = sizeof(se->event_id.header);
9070 } else {
9071 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
9072 se->event_id.header.size = sizeof(se->event_id);
9073 se->event_id.next_prev_pid =
9074 perf_event_pid(event, se->next_prev);
9075 se->event_id.next_prev_tid =
9076 perf_event_tid(event, se->next_prev);
9077 }
9078
9079 perf_event_header__init_id(&se->event_id.header, &sample, event);
9080
9081 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
9082 if (ret)
9083 return;
9084
9085 if (event->ctx->task)
9086 perf_output_put(&handle, se->event_id.header);
9087 else
9088 perf_output_put(&handle, se->event_id);
9089
9090 perf_event__output_id_sample(event, &handle, &sample);
9091
9092 perf_output_end(&handle);
9093 }
9094
perf_event_switch(struct task_struct * task,struct task_struct * next_prev,bool sched_in)9095 static void perf_event_switch(struct task_struct *task,
9096 struct task_struct *next_prev, bool sched_in)
9097 {
9098 struct perf_switch_event switch_event;
9099
9100 /* N.B. caller checks nr_switch_events != 0 */
9101
9102 switch_event = (struct perf_switch_event){
9103 .task = task,
9104 .next_prev = next_prev,
9105 .event_id = {
9106 .header = {
9107 /* .type */
9108 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
9109 /* .size */
9110 },
9111 /* .next_prev_pid */
9112 /* .next_prev_tid */
9113 },
9114 };
9115
9116 if (!sched_in && task->on_rq) {
9117 switch_event.event_id.header.misc |=
9118 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
9119 }
9120
9121 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
9122 }
9123
9124 /*
9125 * IRQ throttle logging
9126 */
9127
perf_log_throttle(struct perf_event * event,int enable)9128 static void perf_log_throttle(struct perf_event *event, int enable)
9129 {
9130 struct perf_output_handle handle;
9131 struct perf_sample_data sample;
9132 int ret;
9133
9134 struct {
9135 struct perf_event_header header;
9136 u64 time;
9137 u64 id;
9138 u64 stream_id;
9139 } throttle_event = {
9140 .header = {
9141 .type = PERF_RECORD_THROTTLE,
9142 .misc = 0,
9143 .size = sizeof(throttle_event),
9144 },
9145 .time = perf_event_clock(event),
9146 .id = primary_event_id(event),
9147 .stream_id = event->id,
9148 };
9149
9150 if (enable)
9151 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
9152
9153 perf_event_header__init_id(&throttle_event.header, &sample, event);
9154
9155 ret = perf_output_begin(&handle, &sample, event,
9156 throttle_event.header.size);
9157 if (ret)
9158 return;
9159
9160 perf_output_put(&handle, throttle_event);
9161 perf_event__output_id_sample(event, &handle, &sample);
9162 perf_output_end(&handle);
9163 }
9164
9165 /*
9166 * ksymbol register/unregister tracking
9167 */
9168
9169 struct perf_ksymbol_event {
9170 const char *name;
9171 int name_len;
9172 struct {
9173 struct perf_event_header header;
9174 u64 addr;
9175 u32 len;
9176 u16 ksym_type;
9177 u16 flags;
9178 } event_id;
9179 };
9180
perf_event_ksymbol_match(struct perf_event * event)9181 static int perf_event_ksymbol_match(struct perf_event *event)
9182 {
9183 return event->attr.ksymbol;
9184 }
9185
perf_event_ksymbol_output(struct perf_event * event,void * data)9186 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
9187 {
9188 struct perf_ksymbol_event *ksymbol_event = data;
9189 struct perf_output_handle handle;
9190 struct perf_sample_data sample;
9191 int ret;
9192
9193 if (!perf_event_ksymbol_match(event))
9194 return;
9195
9196 perf_event_header__init_id(&ksymbol_event->event_id.header,
9197 &sample, event);
9198 ret = perf_output_begin(&handle, &sample, event,
9199 ksymbol_event->event_id.header.size);
9200 if (ret)
9201 return;
9202
9203 perf_output_put(&handle, ksymbol_event->event_id);
9204 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
9205 perf_event__output_id_sample(event, &handle, &sample);
9206
9207 perf_output_end(&handle);
9208 }
9209
perf_event_ksymbol(u16 ksym_type,u64 addr,u32 len,bool unregister,const char * sym)9210 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
9211 const char *sym)
9212 {
9213 struct perf_ksymbol_event ksymbol_event;
9214 char name[KSYM_NAME_LEN];
9215 u16 flags = 0;
9216 int name_len;
9217
9218 if (!atomic_read(&nr_ksymbol_events))
9219 return;
9220
9221 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
9222 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
9223 goto err;
9224
9225 strscpy(name, sym, KSYM_NAME_LEN);
9226 name_len = strlen(name) + 1;
9227 while (!IS_ALIGNED(name_len, sizeof(u64)))
9228 name[name_len++] = '\0';
9229 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
9230
9231 if (unregister)
9232 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
9233
9234 ksymbol_event = (struct perf_ksymbol_event){
9235 .name = name,
9236 .name_len = name_len,
9237 .event_id = {
9238 .header = {
9239 .type = PERF_RECORD_KSYMBOL,
9240 .size = sizeof(ksymbol_event.event_id) +
9241 name_len,
9242 },
9243 .addr = addr,
9244 .len = len,
9245 .ksym_type = ksym_type,
9246 .flags = flags,
9247 },
9248 };
9249
9250 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
9251 return;
9252 err:
9253 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
9254 }
9255
9256 /*
9257 * bpf program load/unload tracking
9258 */
9259
9260 struct perf_bpf_event {
9261 struct bpf_prog *prog;
9262 struct {
9263 struct perf_event_header header;
9264 u16 type;
9265 u16 flags;
9266 u32 id;
9267 u8 tag[BPF_TAG_SIZE];
9268 } event_id;
9269 };
9270
perf_event_bpf_match(struct perf_event * event)9271 static int perf_event_bpf_match(struct perf_event *event)
9272 {
9273 return event->attr.bpf_event;
9274 }
9275
perf_event_bpf_output(struct perf_event * event,void * data)9276 static void perf_event_bpf_output(struct perf_event *event, void *data)
9277 {
9278 struct perf_bpf_event *bpf_event = data;
9279 struct perf_output_handle handle;
9280 struct perf_sample_data sample;
9281 int ret;
9282
9283 if (!perf_event_bpf_match(event))
9284 return;
9285
9286 perf_event_header__init_id(&bpf_event->event_id.header,
9287 &sample, event);
9288 ret = perf_output_begin(&handle, &sample, event,
9289 bpf_event->event_id.header.size);
9290 if (ret)
9291 return;
9292
9293 perf_output_put(&handle, bpf_event->event_id);
9294 perf_event__output_id_sample(event, &handle, &sample);
9295
9296 perf_output_end(&handle);
9297 }
9298
perf_event_bpf_emit_ksymbols(struct bpf_prog * prog,enum perf_bpf_event_type type)9299 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9300 enum perf_bpf_event_type type)
9301 {
9302 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9303 int i;
9304
9305 if (prog->aux->func_cnt == 0) {
9306 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9307 (u64)(unsigned long)prog->bpf_func,
9308 prog->jited_len, unregister,
9309 prog->aux->ksym.name);
9310 } else {
9311 for (i = 0; i < prog->aux->func_cnt; i++) {
9312 struct bpf_prog *subprog = prog->aux->func[i];
9313
9314 perf_event_ksymbol(
9315 PERF_RECORD_KSYMBOL_TYPE_BPF,
9316 (u64)(unsigned long)subprog->bpf_func,
9317 subprog->jited_len, unregister,
9318 subprog->aux->ksym.name);
9319 }
9320 }
9321 }
9322
perf_event_bpf_event(struct bpf_prog * prog,enum perf_bpf_event_type type,u16 flags)9323 void perf_event_bpf_event(struct bpf_prog *prog,
9324 enum perf_bpf_event_type type,
9325 u16 flags)
9326 {
9327 struct perf_bpf_event bpf_event;
9328
9329 switch (type) {
9330 case PERF_BPF_EVENT_PROG_LOAD:
9331 case PERF_BPF_EVENT_PROG_UNLOAD:
9332 if (atomic_read(&nr_ksymbol_events))
9333 perf_event_bpf_emit_ksymbols(prog, type);
9334 break;
9335 default:
9336 return;
9337 }
9338
9339 if (!atomic_read(&nr_bpf_events))
9340 return;
9341
9342 bpf_event = (struct perf_bpf_event){
9343 .prog = prog,
9344 .event_id = {
9345 .header = {
9346 .type = PERF_RECORD_BPF_EVENT,
9347 .size = sizeof(bpf_event.event_id),
9348 },
9349 .type = type,
9350 .flags = flags,
9351 .id = prog->aux->id,
9352 },
9353 };
9354
9355 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9356
9357 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9358 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9359 }
9360
9361 struct perf_text_poke_event {
9362 const void *old_bytes;
9363 const void *new_bytes;
9364 size_t pad;
9365 u16 old_len;
9366 u16 new_len;
9367
9368 struct {
9369 struct perf_event_header header;
9370
9371 u64 addr;
9372 } event_id;
9373 };
9374
perf_event_text_poke_match(struct perf_event * event)9375 static int perf_event_text_poke_match(struct perf_event *event)
9376 {
9377 return event->attr.text_poke;
9378 }
9379
perf_event_text_poke_output(struct perf_event * event,void * data)9380 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9381 {
9382 struct perf_text_poke_event *text_poke_event = data;
9383 struct perf_output_handle handle;
9384 struct perf_sample_data sample;
9385 u64 padding = 0;
9386 int ret;
9387
9388 if (!perf_event_text_poke_match(event))
9389 return;
9390
9391 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9392
9393 ret = perf_output_begin(&handle, &sample, event,
9394 text_poke_event->event_id.header.size);
9395 if (ret)
9396 return;
9397
9398 perf_output_put(&handle, text_poke_event->event_id);
9399 perf_output_put(&handle, text_poke_event->old_len);
9400 perf_output_put(&handle, text_poke_event->new_len);
9401
9402 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9403 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9404
9405 if (text_poke_event->pad)
9406 __output_copy(&handle, &padding, text_poke_event->pad);
9407
9408 perf_event__output_id_sample(event, &handle, &sample);
9409
9410 perf_output_end(&handle);
9411 }
9412
perf_event_text_poke(const void * addr,const void * old_bytes,size_t old_len,const void * new_bytes,size_t new_len)9413 void perf_event_text_poke(const void *addr, const void *old_bytes,
9414 size_t old_len, const void *new_bytes, size_t new_len)
9415 {
9416 struct perf_text_poke_event text_poke_event;
9417 size_t tot, pad;
9418
9419 if (!atomic_read(&nr_text_poke_events))
9420 return;
9421
9422 tot = sizeof(text_poke_event.old_len) + old_len;
9423 tot += sizeof(text_poke_event.new_len) + new_len;
9424 pad = ALIGN(tot, sizeof(u64)) - tot;
9425
9426 text_poke_event = (struct perf_text_poke_event){
9427 .old_bytes = old_bytes,
9428 .new_bytes = new_bytes,
9429 .pad = pad,
9430 .old_len = old_len,
9431 .new_len = new_len,
9432 .event_id = {
9433 .header = {
9434 .type = PERF_RECORD_TEXT_POKE,
9435 .misc = PERF_RECORD_MISC_KERNEL,
9436 .size = sizeof(text_poke_event.event_id) + tot + pad,
9437 },
9438 .addr = (unsigned long)addr,
9439 },
9440 };
9441
9442 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9443 }
9444
perf_event_itrace_started(struct perf_event * event)9445 void perf_event_itrace_started(struct perf_event *event)
9446 {
9447 event->attach_state |= PERF_ATTACH_ITRACE;
9448 }
9449
perf_log_itrace_start(struct perf_event * event)9450 static void perf_log_itrace_start(struct perf_event *event)
9451 {
9452 struct perf_output_handle handle;
9453 struct perf_sample_data sample;
9454 struct perf_aux_event {
9455 struct perf_event_header header;
9456 u32 pid;
9457 u32 tid;
9458 } rec;
9459 int ret;
9460
9461 if (event->parent)
9462 event = event->parent;
9463
9464 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9465 event->attach_state & PERF_ATTACH_ITRACE)
9466 return;
9467
9468 rec.header.type = PERF_RECORD_ITRACE_START;
9469 rec.header.misc = 0;
9470 rec.header.size = sizeof(rec);
9471 rec.pid = perf_event_pid(event, current);
9472 rec.tid = perf_event_tid(event, current);
9473
9474 perf_event_header__init_id(&rec.header, &sample, event);
9475 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9476
9477 if (ret)
9478 return;
9479
9480 perf_output_put(&handle, rec);
9481 perf_event__output_id_sample(event, &handle, &sample);
9482
9483 perf_output_end(&handle);
9484 }
9485
perf_report_aux_output_id(struct perf_event * event,u64 hw_id)9486 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9487 {
9488 struct perf_output_handle handle;
9489 struct perf_sample_data sample;
9490 struct perf_aux_event {
9491 struct perf_event_header header;
9492 u64 hw_id;
9493 } rec;
9494 int ret;
9495
9496 if (event->parent)
9497 event = event->parent;
9498
9499 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9500 rec.header.misc = 0;
9501 rec.header.size = sizeof(rec);
9502 rec.hw_id = hw_id;
9503
9504 perf_event_header__init_id(&rec.header, &sample, event);
9505 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9506
9507 if (ret)
9508 return;
9509
9510 perf_output_put(&handle, rec);
9511 perf_event__output_id_sample(event, &handle, &sample);
9512
9513 perf_output_end(&handle);
9514 }
9515 EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
9516
9517 static int
__perf_event_account_interrupt(struct perf_event * event,int throttle)9518 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9519 {
9520 struct hw_perf_event *hwc = &event->hw;
9521 int ret = 0;
9522 u64 seq;
9523
9524 seq = __this_cpu_read(perf_throttled_seq);
9525 if (seq != hwc->interrupts_seq) {
9526 hwc->interrupts_seq = seq;
9527 hwc->interrupts = 1;
9528 } else {
9529 hwc->interrupts++;
9530 if (unlikely(throttle &&
9531 hwc->interrupts > max_samples_per_tick)) {
9532 __this_cpu_inc(perf_throttled_count);
9533 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9534 hwc->interrupts = MAX_INTERRUPTS;
9535 perf_log_throttle(event, 0);
9536 ret = 1;
9537 }
9538 }
9539
9540 if (event->attr.freq) {
9541 u64 now = perf_clock();
9542 s64 delta = now - hwc->freq_time_stamp;
9543
9544 hwc->freq_time_stamp = now;
9545
9546 if (delta > 0 && delta < 2*TICK_NSEC)
9547 perf_adjust_period(event, delta, hwc->last_period, true);
9548 }
9549
9550 return ret;
9551 }
9552
perf_event_account_interrupt(struct perf_event * event)9553 int perf_event_account_interrupt(struct perf_event *event)
9554 {
9555 return __perf_event_account_interrupt(event, 1);
9556 }
9557
sample_is_allowed(struct perf_event * event,struct pt_regs * regs)9558 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
9559 {
9560 /*
9561 * Due to interrupt latency (AKA "skid"), we may enter the
9562 * kernel before taking an overflow, even if the PMU is only
9563 * counting user events.
9564 */
9565 if (event->attr.exclude_kernel && !user_mode(regs))
9566 return false;
9567
9568 return true;
9569 }
9570
9571 #ifdef CONFIG_BPF_SYSCALL
bpf_overflow_handler(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9572 static int bpf_overflow_handler(struct perf_event *event,
9573 struct perf_sample_data *data,
9574 struct pt_regs *regs)
9575 {
9576 struct bpf_perf_event_data_kern ctx = {
9577 .data = data,
9578 .event = event,
9579 };
9580 struct bpf_prog *prog;
9581 int ret = 0;
9582
9583 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9584 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9585 goto out;
9586 rcu_read_lock();
9587 prog = READ_ONCE(event->prog);
9588 if (prog) {
9589 perf_prepare_sample(data, event, regs);
9590 ret = bpf_prog_run(prog, &ctx);
9591 }
9592 rcu_read_unlock();
9593 out:
9594 __this_cpu_dec(bpf_prog_active);
9595
9596 return ret;
9597 }
9598
perf_event_set_bpf_handler(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)9599 static inline int perf_event_set_bpf_handler(struct perf_event *event,
9600 struct bpf_prog *prog,
9601 u64 bpf_cookie)
9602 {
9603 if (event->overflow_handler_context)
9604 /* hw breakpoint or kernel counter */
9605 return -EINVAL;
9606
9607 if (event->prog)
9608 return -EEXIST;
9609
9610 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
9611 return -EINVAL;
9612
9613 if (event->attr.precise_ip &&
9614 prog->call_get_stack &&
9615 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
9616 event->attr.exclude_callchain_kernel ||
9617 event->attr.exclude_callchain_user)) {
9618 /*
9619 * On perf_event with precise_ip, calling bpf_get_stack()
9620 * may trigger unwinder warnings and occasional crashes.
9621 * bpf_get_[stack|stackid] works around this issue by using
9622 * callchain attached to perf_sample_data. If the
9623 * perf_event does not full (kernel and user) callchain
9624 * attached to perf_sample_data, do not allow attaching BPF
9625 * program that calls bpf_get_[stack|stackid].
9626 */
9627 return -EPROTO;
9628 }
9629
9630 event->prog = prog;
9631 event->bpf_cookie = bpf_cookie;
9632 return 0;
9633 }
9634
perf_event_free_bpf_handler(struct perf_event * event)9635 static inline void perf_event_free_bpf_handler(struct perf_event *event)
9636 {
9637 struct bpf_prog *prog = event->prog;
9638
9639 if (!prog)
9640 return;
9641
9642 event->prog = NULL;
9643 bpf_prog_put(prog);
9644 }
9645 #else
bpf_overflow_handler(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9646 static inline int bpf_overflow_handler(struct perf_event *event,
9647 struct perf_sample_data *data,
9648 struct pt_regs *regs)
9649 {
9650 return 1;
9651 }
9652
perf_event_set_bpf_handler(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)9653 static inline int perf_event_set_bpf_handler(struct perf_event *event,
9654 struct bpf_prog *prog,
9655 u64 bpf_cookie)
9656 {
9657 return -EOPNOTSUPP;
9658 }
9659
perf_event_free_bpf_handler(struct perf_event * event)9660 static inline void perf_event_free_bpf_handler(struct perf_event *event)
9661 {
9662 }
9663 #endif
9664
9665 /*
9666 * Generic event overflow handling, sampling.
9667 */
9668
__perf_event_overflow(struct perf_event * event,int throttle,struct perf_sample_data * data,struct pt_regs * regs)9669 static int __perf_event_overflow(struct perf_event *event,
9670 int throttle, struct perf_sample_data *data,
9671 struct pt_regs *regs)
9672 {
9673 int events = atomic_read(&event->event_limit);
9674 int ret = 0;
9675
9676 /*
9677 * Non-sampling counters might still use the PMI to fold short
9678 * hardware counters, ignore those.
9679 */
9680 if (unlikely(!is_sampling_event(event)))
9681 return 0;
9682
9683 ret = __perf_event_account_interrupt(event, throttle);
9684
9685 if (event->prog && !bpf_overflow_handler(event, data, regs))
9686 return ret;
9687
9688 /*
9689 * XXX event_limit might not quite work as expected on inherited
9690 * events
9691 */
9692
9693 event->pending_kill = POLL_IN;
9694 if (events && atomic_dec_and_test(&event->event_limit)) {
9695 ret = 1;
9696 event->pending_kill = POLL_HUP;
9697 perf_event_disable_inatomic(event);
9698 }
9699
9700 if (event->attr.sigtrap) {
9701 /*
9702 * The desired behaviour of sigtrap vs invalid samples is a bit
9703 * tricky; on the one hand, one should not loose the SIGTRAP if
9704 * it is the first event, on the other hand, we should also not
9705 * trigger the WARN or override the data address.
9706 */
9707 bool valid_sample = sample_is_allowed(event, regs);
9708 unsigned int pending_id = 1;
9709
9710 if (regs)
9711 pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
9712 if (!event->pending_sigtrap) {
9713 event->pending_sigtrap = pending_id;
9714 local_inc(&event->ctx->nr_pending);
9715 } else if (event->attr.exclude_kernel && valid_sample) {
9716 /*
9717 * Should not be able to return to user space without
9718 * consuming pending_sigtrap; with exceptions:
9719 *
9720 * 1. Where !exclude_kernel, events can overflow again
9721 * in the kernel without returning to user space.
9722 *
9723 * 2. Events that can overflow again before the IRQ-
9724 * work without user space progress (e.g. hrtimer).
9725 * To approximate progress (with false negatives),
9726 * check 32-bit hash of the current IP.
9727 */
9728 WARN_ON_ONCE(event->pending_sigtrap != pending_id);
9729 }
9730
9731 event->pending_addr = 0;
9732 if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
9733 event->pending_addr = data->addr;
9734 irq_work_queue(&event->pending_irq);
9735 }
9736
9737 READ_ONCE(event->overflow_handler)(event, data, regs);
9738
9739 if (*perf_event_fasync(event) && event->pending_kill) {
9740 event->pending_wakeup = 1;
9741 irq_work_queue(&event->pending_irq);
9742 }
9743
9744 return ret;
9745 }
9746
perf_event_overflow(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)9747 int perf_event_overflow(struct perf_event *event,
9748 struct perf_sample_data *data,
9749 struct pt_regs *regs)
9750 {
9751 return __perf_event_overflow(event, 1, data, regs);
9752 }
9753
9754 /*
9755 * Generic software event infrastructure
9756 */
9757
9758 struct swevent_htable {
9759 struct swevent_hlist *swevent_hlist;
9760 struct mutex hlist_mutex;
9761 int hlist_refcount;
9762
9763 /* Recursion avoidance in each contexts */
9764 int recursion[PERF_NR_CONTEXTS];
9765 };
9766
9767 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9768
9769 /*
9770 * We directly increment event->count and keep a second value in
9771 * event->hw.period_left to count intervals. This period event
9772 * is kept in the range [-sample_period, 0] so that we can use the
9773 * sign as trigger.
9774 */
9775
perf_swevent_set_period(struct perf_event * event)9776 u64 perf_swevent_set_period(struct perf_event *event)
9777 {
9778 struct hw_perf_event *hwc = &event->hw;
9779 u64 period = hwc->last_period;
9780 u64 nr, offset;
9781 s64 old, val;
9782
9783 hwc->last_period = hwc->sample_period;
9784
9785 old = local64_read(&hwc->period_left);
9786 do {
9787 val = old;
9788 if (val < 0)
9789 return 0;
9790
9791 nr = div64_u64(period + val, period);
9792 offset = nr * period;
9793 val -= offset;
9794 } while (!local64_try_cmpxchg(&hwc->period_left, &old, val));
9795
9796 return nr;
9797 }
9798
perf_swevent_overflow(struct perf_event * event,u64 overflow,struct perf_sample_data * data,struct pt_regs * regs)9799 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9800 struct perf_sample_data *data,
9801 struct pt_regs *regs)
9802 {
9803 struct hw_perf_event *hwc = &event->hw;
9804 int throttle = 0;
9805
9806 if (!overflow)
9807 overflow = perf_swevent_set_period(event);
9808
9809 if (hwc->interrupts == MAX_INTERRUPTS)
9810 return;
9811
9812 for (; overflow; overflow--) {
9813 if (__perf_event_overflow(event, throttle,
9814 data, regs)) {
9815 /*
9816 * We inhibit the overflow from happening when
9817 * hwc->interrupts == MAX_INTERRUPTS.
9818 */
9819 break;
9820 }
9821 throttle = 1;
9822 }
9823 }
9824
perf_swevent_event(struct perf_event * event,u64 nr,struct perf_sample_data * data,struct pt_regs * regs)9825 static void perf_swevent_event(struct perf_event *event, u64 nr,
9826 struct perf_sample_data *data,
9827 struct pt_regs *regs)
9828 {
9829 struct hw_perf_event *hwc = &event->hw;
9830
9831 local64_add(nr, &event->count);
9832
9833 if (!regs)
9834 return;
9835
9836 if (!is_sampling_event(event))
9837 return;
9838
9839 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9840 data->period = nr;
9841 return perf_swevent_overflow(event, 1, data, regs);
9842 } else
9843 data->period = event->hw.last_period;
9844
9845 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9846 return perf_swevent_overflow(event, 1, data, regs);
9847
9848 if (local64_add_negative(nr, &hwc->period_left))
9849 return;
9850
9851 perf_swevent_overflow(event, 0, data, regs);
9852 }
9853
perf_exclude_event(struct perf_event * event,struct pt_regs * regs)9854 static int perf_exclude_event(struct perf_event *event,
9855 struct pt_regs *regs)
9856 {
9857 if (event->hw.state & PERF_HES_STOPPED)
9858 return 1;
9859
9860 if (regs) {
9861 if (event->attr.exclude_user && user_mode(regs))
9862 return 1;
9863
9864 if (event->attr.exclude_kernel && !user_mode(regs))
9865 return 1;
9866 }
9867
9868 return 0;
9869 }
9870
perf_swevent_match(struct perf_event * event,enum perf_type_id type,u32 event_id,struct perf_sample_data * data,struct pt_regs * regs)9871 static int perf_swevent_match(struct perf_event *event,
9872 enum perf_type_id type,
9873 u32 event_id,
9874 struct perf_sample_data *data,
9875 struct pt_regs *regs)
9876 {
9877 if (event->attr.type != type)
9878 return 0;
9879
9880 if (event->attr.config != event_id)
9881 return 0;
9882
9883 if (perf_exclude_event(event, regs))
9884 return 0;
9885
9886 return 1;
9887 }
9888
swevent_hash(u64 type,u32 event_id)9889 static inline u64 swevent_hash(u64 type, u32 event_id)
9890 {
9891 u64 val = event_id | (type << 32);
9892
9893 return hash_64(val, SWEVENT_HLIST_BITS);
9894 }
9895
9896 static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist * hlist,u64 type,u32 event_id)9897 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9898 {
9899 u64 hash = swevent_hash(type, event_id);
9900
9901 return &hlist->heads[hash];
9902 }
9903
9904 /* For the read side: events when they trigger */
9905 static inline struct hlist_head *
find_swevent_head_rcu(struct swevent_htable * swhash,u64 type,u32 event_id)9906 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9907 {
9908 struct swevent_hlist *hlist;
9909
9910 hlist = rcu_dereference(swhash->swevent_hlist);
9911 if (!hlist)
9912 return NULL;
9913
9914 return __find_swevent_head(hlist, type, event_id);
9915 }
9916
9917 /* For the event head insertion and removal in the hlist */
9918 static inline struct hlist_head *
find_swevent_head(struct swevent_htable * swhash,struct perf_event * event)9919 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9920 {
9921 struct swevent_hlist *hlist;
9922 u32 event_id = event->attr.config;
9923 u64 type = event->attr.type;
9924
9925 /*
9926 * Event scheduling is always serialized against hlist allocation
9927 * and release. Which makes the protected version suitable here.
9928 * The context lock guarantees that.
9929 */
9930 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9931 lockdep_is_held(&event->ctx->lock));
9932 if (!hlist)
9933 return NULL;
9934
9935 return __find_swevent_head(hlist, type, event_id);
9936 }
9937
do_perf_sw_event(enum perf_type_id type,u32 event_id,u64 nr,struct perf_sample_data * data,struct pt_regs * regs)9938 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9939 u64 nr,
9940 struct perf_sample_data *data,
9941 struct pt_regs *regs)
9942 {
9943 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9944 struct perf_event *event;
9945 struct hlist_head *head;
9946
9947 rcu_read_lock();
9948 head = find_swevent_head_rcu(swhash, type, event_id);
9949 if (!head)
9950 goto end;
9951
9952 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9953 if (perf_swevent_match(event, type, event_id, data, regs))
9954 perf_swevent_event(event, nr, data, regs);
9955 }
9956 end:
9957 rcu_read_unlock();
9958 }
9959
9960 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9961
perf_swevent_get_recursion_context(void)9962 int perf_swevent_get_recursion_context(void)
9963 {
9964 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9965
9966 return get_recursion_context(swhash->recursion);
9967 }
9968 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9969
perf_swevent_put_recursion_context(int rctx)9970 void perf_swevent_put_recursion_context(int rctx)
9971 {
9972 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9973
9974 put_recursion_context(swhash->recursion, rctx);
9975 }
9976
___perf_sw_event(u32 event_id,u64 nr,struct pt_regs * regs,u64 addr)9977 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9978 {
9979 struct perf_sample_data data;
9980
9981 if (WARN_ON_ONCE(!regs))
9982 return;
9983
9984 perf_sample_data_init(&data, addr, 0);
9985 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9986 }
9987
__perf_sw_event(u32 event_id,u64 nr,struct pt_regs * regs,u64 addr)9988 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9989 {
9990 int rctx;
9991
9992 preempt_disable_notrace();
9993 rctx = perf_swevent_get_recursion_context();
9994 if (unlikely(rctx < 0))
9995 goto fail;
9996
9997 ___perf_sw_event(event_id, nr, regs, addr);
9998
9999 perf_swevent_put_recursion_context(rctx);
10000 fail:
10001 preempt_enable_notrace();
10002 }
10003
perf_swevent_read(struct perf_event * event)10004 static void perf_swevent_read(struct perf_event *event)
10005 {
10006 }
10007
perf_swevent_add(struct perf_event * event,int flags)10008 static int perf_swevent_add(struct perf_event *event, int flags)
10009 {
10010 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
10011 struct hw_perf_event *hwc = &event->hw;
10012 struct hlist_head *head;
10013
10014 if (is_sampling_event(event)) {
10015 hwc->last_period = hwc->sample_period;
10016 perf_swevent_set_period(event);
10017 }
10018
10019 hwc->state = !(flags & PERF_EF_START);
10020
10021 head = find_swevent_head(swhash, event);
10022 if (WARN_ON_ONCE(!head))
10023 return -EINVAL;
10024
10025 hlist_add_head_rcu(&event->hlist_entry, head);
10026 perf_event_update_userpage(event);
10027
10028 return 0;
10029 }
10030
perf_swevent_del(struct perf_event * event,int flags)10031 static void perf_swevent_del(struct perf_event *event, int flags)
10032 {
10033 hlist_del_rcu(&event->hlist_entry);
10034 }
10035
perf_swevent_start(struct perf_event * event,int flags)10036 static void perf_swevent_start(struct perf_event *event, int flags)
10037 {
10038 event->hw.state = 0;
10039 }
10040
perf_swevent_stop(struct perf_event * event,int flags)10041 static void perf_swevent_stop(struct perf_event *event, int flags)
10042 {
10043 event->hw.state = PERF_HES_STOPPED;
10044 }
10045
10046 /* Deref the hlist from the update side */
10047 static inline struct swevent_hlist *
swevent_hlist_deref(struct swevent_htable * swhash)10048 swevent_hlist_deref(struct swevent_htable *swhash)
10049 {
10050 return rcu_dereference_protected(swhash->swevent_hlist,
10051 lockdep_is_held(&swhash->hlist_mutex));
10052 }
10053
swevent_hlist_release(struct swevent_htable * swhash)10054 static void swevent_hlist_release(struct swevent_htable *swhash)
10055 {
10056 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
10057
10058 if (!hlist)
10059 return;
10060
10061 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
10062 kfree_rcu(hlist, rcu_head);
10063 }
10064
swevent_hlist_put_cpu(int cpu)10065 static void swevent_hlist_put_cpu(int cpu)
10066 {
10067 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10068
10069 mutex_lock(&swhash->hlist_mutex);
10070
10071 if (!--swhash->hlist_refcount)
10072 swevent_hlist_release(swhash);
10073
10074 mutex_unlock(&swhash->hlist_mutex);
10075 }
10076
swevent_hlist_put(void)10077 static void swevent_hlist_put(void)
10078 {
10079 int cpu;
10080
10081 for_each_possible_cpu(cpu)
10082 swevent_hlist_put_cpu(cpu);
10083 }
10084
swevent_hlist_get_cpu(int cpu)10085 static int swevent_hlist_get_cpu(int cpu)
10086 {
10087 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10088 int err = 0;
10089
10090 mutex_lock(&swhash->hlist_mutex);
10091 if (!swevent_hlist_deref(swhash) &&
10092 cpumask_test_cpu(cpu, perf_online_mask)) {
10093 struct swevent_hlist *hlist;
10094
10095 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
10096 if (!hlist) {
10097 err = -ENOMEM;
10098 goto exit;
10099 }
10100 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10101 }
10102 swhash->hlist_refcount++;
10103 exit:
10104 mutex_unlock(&swhash->hlist_mutex);
10105
10106 return err;
10107 }
10108
swevent_hlist_get(void)10109 static int swevent_hlist_get(void)
10110 {
10111 int err, cpu, failed_cpu;
10112
10113 mutex_lock(&pmus_lock);
10114 for_each_possible_cpu(cpu) {
10115 err = swevent_hlist_get_cpu(cpu);
10116 if (err) {
10117 failed_cpu = cpu;
10118 goto fail;
10119 }
10120 }
10121 mutex_unlock(&pmus_lock);
10122 return 0;
10123 fail:
10124 for_each_possible_cpu(cpu) {
10125 if (cpu == failed_cpu)
10126 break;
10127 swevent_hlist_put_cpu(cpu);
10128 }
10129 mutex_unlock(&pmus_lock);
10130 return err;
10131 }
10132
10133 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
10134
sw_perf_event_destroy(struct perf_event * event)10135 static void sw_perf_event_destroy(struct perf_event *event)
10136 {
10137 u64 event_id = event->attr.config;
10138
10139 WARN_ON(event->parent);
10140
10141 static_key_slow_dec(&perf_swevent_enabled[event_id]);
10142 swevent_hlist_put();
10143 }
10144
10145 static struct pmu perf_cpu_clock; /* fwd declaration */
10146 static struct pmu perf_task_clock;
10147
perf_swevent_init(struct perf_event * event)10148 static int perf_swevent_init(struct perf_event *event)
10149 {
10150 u64 event_id = event->attr.config;
10151
10152 if (event->attr.type != PERF_TYPE_SOFTWARE)
10153 return -ENOENT;
10154
10155 /*
10156 * no branch sampling for software events
10157 */
10158 if (has_branch_stack(event))
10159 return -EOPNOTSUPP;
10160
10161 switch (event_id) {
10162 case PERF_COUNT_SW_CPU_CLOCK:
10163 event->attr.type = perf_cpu_clock.type;
10164 return -ENOENT;
10165 case PERF_COUNT_SW_TASK_CLOCK:
10166 event->attr.type = perf_task_clock.type;
10167 return -ENOENT;
10168
10169 default:
10170 break;
10171 }
10172
10173 if (event_id >= PERF_COUNT_SW_MAX)
10174 return -ENOENT;
10175
10176 if (!event->parent) {
10177 int err;
10178
10179 err = swevent_hlist_get();
10180 if (err)
10181 return err;
10182
10183 static_key_slow_inc(&perf_swevent_enabled[event_id]);
10184 event->destroy = sw_perf_event_destroy;
10185 }
10186
10187 return 0;
10188 }
10189
10190 static struct pmu perf_swevent = {
10191 .task_ctx_nr = perf_sw_context,
10192
10193 .capabilities = PERF_PMU_CAP_NO_NMI,
10194
10195 .event_init = perf_swevent_init,
10196 .add = perf_swevent_add,
10197 .del = perf_swevent_del,
10198 .start = perf_swevent_start,
10199 .stop = perf_swevent_stop,
10200 .read = perf_swevent_read,
10201 };
10202
10203 #ifdef CONFIG_EVENT_TRACING
10204
tp_perf_event_destroy(struct perf_event * event)10205 static void tp_perf_event_destroy(struct perf_event *event)
10206 {
10207 perf_trace_destroy(event);
10208 }
10209
perf_tp_event_init(struct perf_event * event)10210 static int perf_tp_event_init(struct perf_event *event)
10211 {
10212 int err;
10213
10214 if (event->attr.type != PERF_TYPE_TRACEPOINT)
10215 return -ENOENT;
10216
10217 /*
10218 * no branch sampling for tracepoint events
10219 */
10220 if (has_branch_stack(event))
10221 return -EOPNOTSUPP;
10222
10223 err = perf_trace_init(event);
10224 if (err)
10225 return err;
10226
10227 event->destroy = tp_perf_event_destroy;
10228
10229 return 0;
10230 }
10231
10232 static struct pmu perf_tracepoint = {
10233 .task_ctx_nr = perf_sw_context,
10234
10235 .event_init = perf_tp_event_init,
10236 .add = perf_trace_add,
10237 .del = perf_trace_del,
10238 .start = perf_swevent_start,
10239 .stop = perf_swevent_stop,
10240 .read = perf_swevent_read,
10241 };
10242
perf_tp_filter_match(struct perf_event * event,struct perf_sample_data * data)10243 static int perf_tp_filter_match(struct perf_event *event,
10244 struct perf_sample_data *data)
10245 {
10246 void *record = data->raw->frag.data;
10247
10248 /* only top level events have filters set */
10249 if (event->parent)
10250 event = event->parent;
10251
10252 if (likely(!event->filter) || filter_match_preds(event->filter, record))
10253 return 1;
10254 return 0;
10255 }
10256
perf_tp_event_match(struct perf_event * event,struct perf_sample_data * data,struct pt_regs * regs)10257 static int perf_tp_event_match(struct perf_event *event,
10258 struct perf_sample_data *data,
10259 struct pt_regs *regs)
10260 {
10261 if (event->hw.state & PERF_HES_STOPPED)
10262 return 0;
10263 /*
10264 * If exclude_kernel, only trace user-space tracepoints (uprobes)
10265 */
10266 if (event->attr.exclude_kernel && !user_mode(regs))
10267 return 0;
10268
10269 if (!perf_tp_filter_match(event, data))
10270 return 0;
10271
10272 return 1;
10273 }
10274
perf_trace_run_bpf_submit(void * raw_data,int size,int rctx,struct trace_event_call * call,u64 count,struct pt_regs * regs,struct hlist_head * head,struct task_struct * task)10275 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
10276 struct trace_event_call *call, u64 count,
10277 struct pt_regs *regs, struct hlist_head *head,
10278 struct task_struct *task)
10279 {
10280 if (bpf_prog_array_valid(call)) {
10281 *(struct pt_regs **)raw_data = regs;
10282 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
10283 perf_swevent_put_recursion_context(rctx);
10284 return;
10285 }
10286 }
10287 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
10288 rctx, task);
10289 }
10290 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
10291
__perf_tp_event_target_task(u64 count,void * record,struct pt_regs * regs,struct perf_sample_data * data,struct perf_event * event)10292 static void __perf_tp_event_target_task(u64 count, void *record,
10293 struct pt_regs *regs,
10294 struct perf_sample_data *data,
10295 struct perf_event *event)
10296 {
10297 struct trace_entry *entry = record;
10298
10299 if (event->attr.config != entry->type)
10300 return;
10301 /* Cannot deliver synchronous signal to other task. */
10302 if (event->attr.sigtrap)
10303 return;
10304 if (perf_tp_event_match(event, data, regs))
10305 perf_swevent_event(event, count, data, regs);
10306 }
10307
perf_tp_event_target_task(u64 count,void * record,struct pt_regs * regs,struct perf_sample_data * data,struct perf_event_context * ctx)10308 static void perf_tp_event_target_task(u64 count, void *record,
10309 struct pt_regs *regs,
10310 struct perf_sample_data *data,
10311 struct perf_event_context *ctx)
10312 {
10313 unsigned int cpu = smp_processor_id();
10314 struct pmu *pmu = &perf_tracepoint;
10315 struct perf_event *event, *sibling;
10316
10317 perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
10318 __perf_tp_event_target_task(count, record, regs, data, event);
10319 for_each_sibling_event(sibling, event)
10320 __perf_tp_event_target_task(count, record, regs, data, sibling);
10321 }
10322
10323 perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
10324 __perf_tp_event_target_task(count, record, regs, data, event);
10325 for_each_sibling_event(sibling, event)
10326 __perf_tp_event_target_task(count, record, regs, data, sibling);
10327 }
10328 }
10329
perf_tp_event(u16 event_type,u64 count,void * record,int entry_size,struct pt_regs * regs,struct hlist_head * head,int rctx,struct task_struct * task)10330 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
10331 struct pt_regs *regs, struct hlist_head *head, int rctx,
10332 struct task_struct *task)
10333 {
10334 struct perf_sample_data data;
10335 struct perf_event *event;
10336
10337 struct perf_raw_record raw = {
10338 .frag = {
10339 .size = entry_size,
10340 .data = record,
10341 },
10342 };
10343
10344 perf_sample_data_init(&data, 0, 0);
10345 perf_sample_save_raw_data(&data, &raw);
10346
10347 perf_trace_buf_update(record, event_type);
10348
10349 hlist_for_each_entry_rcu(event, head, hlist_entry) {
10350 if (perf_tp_event_match(event, &data, regs)) {
10351 perf_swevent_event(event, count, &data, regs);
10352
10353 /*
10354 * Here use the same on-stack perf_sample_data,
10355 * some members in data are event-specific and
10356 * need to be re-computed for different sweveents.
10357 * Re-initialize data->sample_flags safely to avoid
10358 * the problem that next event skips preparing data
10359 * because data->sample_flags is set.
10360 */
10361 perf_sample_data_init(&data, 0, 0);
10362 perf_sample_save_raw_data(&data, &raw);
10363 }
10364 }
10365
10366 /*
10367 * If we got specified a target task, also iterate its context and
10368 * deliver this event there too.
10369 */
10370 if (task && task != current) {
10371 struct perf_event_context *ctx;
10372
10373 rcu_read_lock();
10374 ctx = rcu_dereference(task->perf_event_ctxp);
10375 if (!ctx)
10376 goto unlock;
10377
10378 raw_spin_lock(&ctx->lock);
10379 perf_tp_event_target_task(count, record, regs, &data, ctx);
10380 raw_spin_unlock(&ctx->lock);
10381 unlock:
10382 rcu_read_unlock();
10383 }
10384
10385 perf_swevent_put_recursion_context(rctx);
10386 }
10387 EXPORT_SYMBOL_GPL(perf_tp_event);
10388
10389 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
10390 /*
10391 * Flags in config, used by dynamic PMU kprobe and uprobe
10392 * The flags should match following PMU_FORMAT_ATTR().
10393 *
10394 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
10395 * if not set, create kprobe/uprobe
10396 *
10397 * The following values specify a reference counter (or semaphore in the
10398 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
10399 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
10400 *
10401 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
10402 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
10403 */
10404 enum perf_probe_config {
10405 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
10406 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
10407 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
10408 };
10409
10410 PMU_FORMAT_ATTR(retprobe, "config:0");
10411 #endif
10412
10413 #ifdef CONFIG_KPROBE_EVENTS
10414 static struct attribute *kprobe_attrs[] = {
10415 &format_attr_retprobe.attr,
10416 NULL,
10417 };
10418
10419 static struct attribute_group kprobe_format_group = {
10420 .name = "format",
10421 .attrs = kprobe_attrs,
10422 };
10423
10424 static const struct attribute_group *kprobe_attr_groups[] = {
10425 &kprobe_format_group,
10426 NULL,
10427 };
10428
10429 static int perf_kprobe_event_init(struct perf_event *event);
10430 static struct pmu perf_kprobe = {
10431 .task_ctx_nr = perf_sw_context,
10432 .event_init = perf_kprobe_event_init,
10433 .add = perf_trace_add,
10434 .del = perf_trace_del,
10435 .start = perf_swevent_start,
10436 .stop = perf_swevent_stop,
10437 .read = perf_swevent_read,
10438 .attr_groups = kprobe_attr_groups,
10439 };
10440
perf_kprobe_event_init(struct perf_event * event)10441 static int perf_kprobe_event_init(struct perf_event *event)
10442 {
10443 int err;
10444 bool is_retprobe;
10445
10446 if (event->attr.type != perf_kprobe.type)
10447 return -ENOENT;
10448
10449 if (!perfmon_capable())
10450 return -EACCES;
10451
10452 /*
10453 * no branch sampling for probe events
10454 */
10455 if (has_branch_stack(event))
10456 return -EOPNOTSUPP;
10457
10458 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10459 err = perf_kprobe_init(event, is_retprobe);
10460 if (err)
10461 return err;
10462
10463 event->destroy = perf_kprobe_destroy;
10464
10465 return 0;
10466 }
10467 #endif /* CONFIG_KPROBE_EVENTS */
10468
10469 #ifdef CONFIG_UPROBE_EVENTS
10470 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
10471
10472 static struct attribute *uprobe_attrs[] = {
10473 &format_attr_retprobe.attr,
10474 &format_attr_ref_ctr_offset.attr,
10475 NULL,
10476 };
10477
10478 static struct attribute_group uprobe_format_group = {
10479 .name = "format",
10480 .attrs = uprobe_attrs,
10481 };
10482
10483 static const struct attribute_group *uprobe_attr_groups[] = {
10484 &uprobe_format_group,
10485 NULL,
10486 };
10487
10488 static int perf_uprobe_event_init(struct perf_event *event);
10489 static struct pmu perf_uprobe = {
10490 .task_ctx_nr = perf_sw_context,
10491 .event_init = perf_uprobe_event_init,
10492 .add = perf_trace_add,
10493 .del = perf_trace_del,
10494 .start = perf_swevent_start,
10495 .stop = perf_swevent_stop,
10496 .read = perf_swevent_read,
10497 .attr_groups = uprobe_attr_groups,
10498 };
10499
perf_uprobe_event_init(struct perf_event * event)10500 static int perf_uprobe_event_init(struct perf_event *event)
10501 {
10502 int err;
10503 unsigned long ref_ctr_offset;
10504 bool is_retprobe;
10505
10506 if (event->attr.type != perf_uprobe.type)
10507 return -ENOENT;
10508
10509 if (!perfmon_capable())
10510 return -EACCES;
10511
10512 /*
10513 * no branch sampling for probe events
10514 */
10515 if (has_branch_stack(event))
10516 return -EOPNOTSUPP;
10517
10518 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10519 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10520 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10521 if (err)
10522 return err;
10523
10524 event->destroy = perf_uprobe_destroy;
10525
10526 return 0;
10527 }
10528 #endif /* CONFIG_UPROBE_EVENTS */
10529
perf_tp_register(void)10530 static inline void perf_tp_register(void)
10531 {
10532 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10533 #ifdef CONFIG_KPROBE_EVENTS
10534 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10535 #endif
10536 #ifdef CONFIG_UPROBE_EVENTS
10537 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10538 #endif
10539 }
10540
perf_event_free_filter(struct perf_event * event)10541 static void perf_event_free_filter(struct perf_event *event)
10542 {
10543 ftrace_profile_free_filter(event);
10544 }
10545
10546 /*
10547 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10548 * with perf_event_open()
10549 */
perf_event_is_tracing(struct perf_event * event)10550 static inline bool perf_event_is_tracing(struct perf_event *event)
10551 {
10552 if (event->pmu == &perf_tracepoint)
10553 return true;
10554 #ifdef CONFIG_KPROBE_EVENTS
10555 if (event->pmu == &perf_kprobe)
10556 return true;
10557 #endif
10558 #ifdef CONFIG_UPROBE_EVENTS
10559 if (event->pmu == &perf_uprobe)
10560 return true;
10561 #endif
10562 return false;
10563 }
10564
perf_event_set_bpf_prog(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)10565 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10566 u64 bpf_cookie)
10567 {
10568 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
10569
10570 if (!perf_event_is_tracing(event))
10571 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10572
10573 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
10574 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
10575 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10576 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10577 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
10578 /* bpf programs can only be attached to u/kprobe or tracepoint */
10579 return -EINVAL;
10580
10581 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
10582 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10583 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10584 return -EINVAL;
10585
10586 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->sleepable && !is_uprobe)
10587 /* only uprobe programs are allowed to be sleepable */
10588 return -EINVAL;
10589
10590 /* Kprobe override only works for kprobes, not uprobes. */
10591 if (prog->kprobe_override && !is_kprobe)
10592 return -EINVAL;
10593
10594 if (is_tracepoint || is_syscall_tp) {
10595 int off = trace_event_get_offsets(event->tp_event);
10596
10597 if (prog->aux->max_ctx_offset > off)
10598 return -EACCES;
10599 }
10600
10601 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10602 }
10603
perf_event_free_bpf_prog(struct perf_event * event)10604 void perf_event_free_bpf_prog(struct perf_event *event)
10605 {
10606 if (!perf_event_is_tracing(event)) {
10607 perf_event_free_bpf_handler(event);
10608 return;
10609 }
10610 perf_event_detach_bpf_prog(event);
10611 }
10612
10613 #else
10614
perf_tp_register(void)10615 static inline void perf_tp_register(void)
10616 {
10617 }
10618
perf_event_free_filter(struct perf_event * event)10619 static void perf_event_free_filter(struct perf_event *event)
10620 {
10621 }
10622
perf_event_set_bpf_prog(struct perf_event * event,struct bpf_prog * prog,u64 bpf_cookie)10623 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10624 u64 bpf_cookie)
10625 {
10626 return -ENOENT;
10627 }
10628
perf_event_free_bpf_prog(struct perf_event * event)10629 void perf_event_free_bpf_prog(struct perf_event *event)
10630 {
10631 }
10632 #endif /* CONFIG_EVENT_TRACING */
10633
10634 #ifdef CONFIG_HAVE_HW_BREAKPOINT
perf_bp_event(struct perf_event * bp,void * data)10635 void perf_bp_event(struct perf_event *bp, void *data)
10636 {
10637 struct perf_sample_data sample;
10638 struct pt_regs *regs = data;
10639
10640 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10641
10642 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10643 perf_swevent_event(bp, 1, &sample, regs);
10644 }
10645 #endif
10646
10647 /*
10648 * Allocate a new address filter
10649 */
10650 static struct perf_addr_filter *
perf_addr_filter_new(struct perf_event * event,struct list_head * filters)10651 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10652 {
10653 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10654 struct perf_addr_filter *filter;
10655
10656 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10657 if (!filter)
10658 return NULL;
10659
10660 INIT_LIST_HEAD(&filter->entry);
10661 list_add_tail(&filter->entry, filters);
10662
10663 return filter;
10664 }
10665
free_filters_list(struct list_head * filters)10666 static void free_filters_list(struct list_head *filters)
10667 {
10668 struct perf_addr_filter *filter, *iter;
10669
10670 list_for_each_entry_safe(filter, iter, filters, entry) {
10671 path_put(&filter->path);
10672 list_del(&filter->entry);
10673 kfree(filter);
10674 }
10675 }
10676
10677 /*
10678 * Free existing address filters and optionally install new ones
10679 */
perf_addr_filters_splice(struct perf_event * event,struct list_head * head)10680 static void perf_addr_filters_splice(struct perf_event *event,
10681 struct list_head *head)
10682 {
10683 unsigned long flags;
10684 LIST_HEAD(list);
10685
10686 if (!has_addr_filter(event))
10687 return;
10688
10689 /* don't bother with children, they don't have their own filters */
10690 if (event->parent)
10691 return;
10692
10693 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10694
10695 list_splice_init(&event->addr_filters.list, &list);
10696 if (head)
10697 list_splice(head, &event->addr_filters.list);
10698
10699 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10700
10701 free_filters_list(&list);
10702 }
10703
10704 /*
10705 * Scan through mm's vmas and see if one of them matches the
10706 * @filter; if so, adjust filter's address range.
10707 * Called with mm::mmap_lock down for reading.
10708 */
perf_addr_filter_apply(struct perf_addr_filter * filter,struct mm_struct * mm,struct perf_addr_filter_range * fr)10709 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10710 struct mm_struct *mm,
10711 struct perf_addr_filter_range *fr)
10712 {
10713 struct vm_area_struct *vma;
10714 VMA_ITERATOR(vmi, mm, 0);
10715
10716 for_each_vma(vmi, vma) {
10717 if (!vma->vm_file)
10718 continue;
10719
10720 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10721 return;
10722 }
10723 }
10724
10725 /*
10726 * Update event's address range filters based on the
10727 * task's existing mappings, if any.
10728 */
perf_event_addr_filters_apply(struct perf_event * event)10729 static void perf_event_addr_filters_apply(struct perf_event *event)
10730 {
10731 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10732 struct task_struct *task = READ_ONCE(event->ctx->task);
10733 struct perf_addr_filter *filter;
10734 struct mm_struct *mm = NULL;
10735 unsigned int count = 0;
10736 unsigned long flags;
10737
10738 /*
10739 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10740 * will stop on the parent's child_mutex that our caller is also holding
10741 */
10742 if (task == TASK_TOMBSTONE)
10743 return;
10744
10745 if (ifh->nr_file_filters) {
10746 mm = get_task_mm(task);
10747 if (!mm)
10748 goto restart;
10749
10750 mmap_read_lock(mm);
10751 }
10752
10753 raw_spin_lock_irqsave(&ifh->lock, flags);
10754 list_for_each_entry(filter, &ifh->list, entry) {
10755 if (filter->path.dentry) {
10756 /*
10757 * Adjust base offset if the filter is associated to a
10758 * binary that needs to be mapped:
10759 */
10760 event->addr_filter_ranges[count].start = 0;
10761 event->addr_filter_ranges[count].size = 0;
10762
10763 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10764 } else {
10765 event->addr_filter_ranges[count].start = filter->offset;
10766 event->addr_filter_ranges[count].size = filter->size;
10767 }
10768
10769 count++;
10770 }
10771
10772 event->addr_filters_gen++;
10773 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10774
10775 if (ifh->nr_file_filters) {
10776 mmap_read_unlock(mm);
10777
10778 mmput(mm);
10779 }
10780
10781 restart:
10782 perf_event_stop(event, 1);
10783 }
10784
10785 /*
10786 * Address range filtering: limiting the data to certain
10787 * instruction address ranges. Filters are ioctl()ed to us from
10788 * userspace as ascii strings.
10789 *
10790 * Filter string format:
10791 *
10792 * ACTION RANGE_SPEC
10793 * where ACTION is one of the
10794 * * "filter": limit the trace to this region
10795 * * "start": start tracing from this address
10796 * * "stop": stop tracing at this address/region;
10797 * RANGE_SPEC is
10798 * * for kernel addresses: <start address>[/<size>]
10799 * * for object files: <start address>[/<size>]@</path/to/object/file>
10800 *
10801 * if <size> is not specified or is zero, the range is treated as a single
10802 * address; not valid for ACTION=="filter".
10803 */
10804 enum {
10805 IF_ACT_NONE = -1,
10806 IF_ACT_FILTER,
10807 IF_ACT_START,
10808 IF_ACT_STOP,
10809 IF_SRC_FILE,
10810 IF_SRC_KERNEL,
10811 IF_SRC_FILEADDR,
10812 IF_SRC_KERNELADDR,
10813 };
10814
10815 enum {
10816 IF_STATE_ACTION = 0,
10817 IF_STATE_SOURCE,
10818 IF_STATE_END,
10819 };
10820
10821 static const match_table_t if_tokens = {
10822 { IF_ACT_FILTER, "filter" },
10823 { IF_ACT_START, "start" },
10824 { IF_ACT_STOP, "stop" },
10825 { IF_SRC_FILE, "%u/%u@%s" },
10826 { IF_SRC_KERNEL, "%u/%u" },
10827 { IF_SRC_FILEADDR, "%u@%s" },
10828 { IF_SRC_KERNELADDR, "%u" },
10829 { IF_ACT_NONE, NULL },
10830 };
10831
10832 /*
10833 * Address filter string parser
10834 */
10835 static int
perf_event_parse_addr_filter(struct perf_event * event,char * fstr,struct list_head * filters)10836 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10837 struct list_head *filters)
10838 {
10839 struct perf_addr_filter *filter = NULL;
10840 char *start, *orig, *filename = NULL;
10841 substring_t args[MAX_OPT_ARGS];
10842 int state = IF_STATE_ACTION, token;
10843 unsigned int kernel = 0;
10844 int ret = -EINVAL;
10845
10846 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10847 if (!fstr)
10848 return -ENOMEM;
10849
10850 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10851 static const enum perf_addr_filter_action_t actions[] = {
10852 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10853 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10854 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10855 };
10856 ret = -EINVAL;
10857
10858 if (!*start)
10859 continue;
10860
10861 /* filter definition begins */
10862 if (state == IF_STATE_ACTION) {
10863 filter = perf_addr_filter_new(event, filters);
10864 if (!filter)
10865 goto fail;
10866 }
10867
10868 token = match_token(start, if_tokens, args);
10869 switch (token) {
10870 case IF_ACT_FILTER:
10871 case IF_ACT_START:
10872 case IF_ACT_STOP:
10873 if (state != IF_STATE_ACTION)
10874 goto fail;
10875
10876 filter->action = actions[token];
10877 state = IF_STATE_SOURCE;
10878 break;
10879
10880 case IF_SRC_KERNELADDR:
10881 case IF_SRC_KERNEL:
10882 kernel = 1;
10883 fallthrough;
10884
10885 case IF_SRC_FILEADDR:
10886 case IF_SRC_FILE:
10887 if (state != IF_STATE_SOURCE)
10888 goto fail;
10889
10890 *args[0].to = 0;
10891 ret = kstrtoul(args[0].from, 0, &filter->offset);
10892 if (ret)
10893 goto fail;
10894
10895 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10896 *args[1].to = 0;
10897 ret = kstrtoul(args[1].from, 0, &filter->size);
10898 if (ret)
10899 goto fail;
10900 }
10901
10902 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10903 int fpos = token == IF_SRC_FILE ? 2 : 1;
10904
10905 kfree(filename);
10906 filename = match_strdup(&args[fpos]);
10907 if (!filename) {
10908 ret = -ENOMEM;
10909 goto fail;
10910 }
10911 }
10912
10913 state = IF_STATE_END;
10914 break;
10915
10916 default:
10917 goto fail;
10918 }
10919
10920 /*
10921 * Filter definition is fully parsed, validate and install it.
10922 * Make sure that it doesn't contradict itself or the event's
10923 * attribute.
10924 */
10925 if (state == IF_STATE_END) {
10926 ret = -EINVAL;
10927
10928 /*
10929 * ACTION "filter" must have a non-zero length region
10930 * specified.
10931 */
10932 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10933 !filter->size)
10934 goto fail;
10935
10936 if (!kernel) {
10937 if (!filename)
10938 goto fail;
10939
10940 /*
10941 * For now, we only support file-based filters
10942 * in per-task events; doing so for CPU-wide
10943 * events requires additional context switching
10944 * trickery, since same object code will be
10945 * mapped at different virtual addresses in
10946 * different processes.
10947 */
10948 ret = -EOPNOTSUPP;
10949 if (!event->ctx->task)
10950 goto fail;
10951
10952 /* look up the path and grab its inode */
10953 ret = kern_path(filename, LOOKUP_FOLLOW,
10954 &filter->path);
10955 if (ret)
10956 goto fail;
10957
10958 ret = -EINVAL;
10959 if (!filter->path.dentry ||
10960 !S_ISREG(d_inode(filter->path.dentry)
10961 ->i_mode))
10962 goto fail;
10963
10964 event->addr_filters.nr_file_filters++;
10965 }
10966
10967 /* ready to consume more filters */
10968 kfree(filename);
10969 filename = NULL;
10970 state = IF_STATE_ACTION;
10971 filter = NULL;
10972 kernel = 0;
10973 }
10974 }
10975
10976 if (state != IF_STATE_ACTION)
10977 goto fail;
10978
10979 kfree(filename);
10980 kfree(orig);
10981
10982 return 0;
10983
10984 fail:
10985 kfree(filename);
10986 free_filters_list(filters);
10987 kfree(orig);
10988
10989 return ret;
10990 }
10991
10992 static int
perf_event_set_addr_filter(struct perf_event * event,char * filter_str)10993 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10994 {
10995 LIST_HEAD(filters);
10996 int ret;
10997
10998 /*
10999 * Since this is called in perf_ioctl() path, we're already holding
11000 * ctx::mutex.
11001 */
11002 lockdep_assert_held(&event->ctx->mutex);
11003
11004 if (WARN_ON_ONCE(event->parent))
11005 return -EINVAL;
11006
11007 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
11008 if (ret)
11009 goto fail_clear_files;
11010
11011 ret = event->pmu->addr_filters_validate(&filters);
11012 if (ret)
11013 goto fail_free_filters;
11014
11015 /* remove existing filters, if any */
11016 perf_addr_filters_splice(event, &filters);
11017
11018 /* install new filters */
11019 perf_event_for_each_child(event, perf_event_addr_filters_apply);
11020
11021 return ret;
11022
11023 fail_free_filters:
11024 free_filters_list(&filters);
11025
11026 fail_clear_files:
11027 event->addr_filters.nr_file_filters = 0;
11028
11029 return ret;
11030 }
11031
perf_event_set_filter(struct perf_event * event,void __user * arg)11032 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
11033 {
11034 int ret = -EINVAL;
11035 char *filter_str;
11036
11037 filter_str = strndup_user(arg, PAGE_SIZE);
11038 if (IS_ERR(filter_str))
11039 return PTR_ERR(filter_str);
11040
11041 #ifdef CONFIG_EVENT_TRACING
11042 if (perf_event_is_tracing(event)) {
11043 struct perf_event_context *ctx = event->ctx;
11044
11045 /*
11046 * Beware, here be dragons!!
11047 *
11048 * the tracepoint muck will deadlock against ctx->mutex, but
11049 * the tracepoint stuff does not actually need it. So
11050 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
11051 * already have a reference on ctx.
11052 *
11053 * This can result in event getting moved to a different ctx,
11054 * but that does not affect the tracepoint state.
11055 */
11056 mutex_unlock(&ctx->mutex);
11057 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
11058 mutex_lock(&ctx->mutex);
11059 } else
11060 #endif
11061 if (has_addr_filter(event))
11062 ret = perf_event_set_addr_filter(event, filter_str);
11063
11064 kfree(filter_str);
11065 return ret;
11066 }
11067
11068 /*
11069 * hrtimer based swevent callback
11070 */
11071
perf_swevent_hrtimer(struct hrtimer * hrtimer)11072 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
11073 {
11074 enum hrtimer_restart ret = HRTIMER_RESTART;
11075 struct perf_sample_data data;
11076 struct pt_regs *regs;
11077 struct perf_event *event;
11078 u64 period;
11079
11080 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
11081
11082 if (event->state != PERF_EVENT_STATE_ACTIVE)
11083 return HRTIMER_NORESTART;
11084
11085 event->pmu->read(event);
11086
11087 perf_sample_data_init(&data, 0, event->hw.last_period);
11088 regs = get_irq_regs();
11089
11090 if (regs && !perf_exclude_event(event, regs)) {
11091 if (!(event->attr.exclude_idle && is_idle_task(current)))
11092 if (__perf_event_overflow(event, 1, &data, regs))
11093 ret = HRTIMER_NORESTART;
11094 }
11095
11096 period = max_t(u64, 10000, event->hw.sample_period);
11097 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
11098
11099 return ret;
11100 }
11101
perf_swevent_start_hrtimer(struct perf_event * event)11102 static void perf_swevent_start_hrtimer(struct perf_event *event)
11103 {
11104 struct hw_perf_event *hwc = &event->hw;
11105 s64 period;
11106
11107 if (!is_sampling_event(event))
11108 return;
11109
11110 period = local64_read(&hwc->period_left);
11111 if (period) {
11112 if (period < 0)
11113 period = 10000;
11114
11115 local64_set(&hwc->period_left, 0);
11116 } else {
11117 period = max_t(u64, 10000, hwc->sample_period);
11118 }
11119 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
11120 HRTIMER_MODE_REL_PINNED_HARD);
11121 }
11122
perf_swevent_cancel_hrtimer(struct perf_event * event)11123 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
11124 {
11125 struct hw_perf_event *hwc = &event->hw;
11126
11127 if (is_sampling_event(event)) {
11128 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
11129 local64_set(&hwc->period_left, ktime_to_ns(remaining));
11130
11131 hrtimer_cancel(&hwc->hrtimer);
11132 }
11133 }
11134
perf_swevent_init_hrtimer(struct perf_event * event)11135 static void perf_swevent_init_hrtimer(struct perf_event *event)
11136 {
11137 struct hw_perf_event *hwc = &event->hw;
11138
11139 if (!is_sampling_event(event))
11140 return;
11141
11142 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
11143 hwc->hrtimer.function = perf_swevent_hrtimer;
11144
11145 /*
11146 * Since hrtimers have a fixed rate, we can do a static freq->period
11147 * mapping and avoid the whole period adjust feedback stuff.
11148 */
11149 if (event->attr.freq) {
11150 long freq = event->attr.sample_freq;
11151
11152 event->attr.sample_period = NSEC_PER_SEC / freq;
11153 hwc->sample_period = event->attr.sample_period;
11154 local64_set(&hwc->period_left, hwc->sample_period);
11155 hwc->last_period = hwc->sample_period;
11156 event->attr.freq = 0;
11157 }
11158 }
11159
11160 /*
11161 * Software event: cpu wall time clock
11162 */
11163
cpu_clock_event_update(struct perf_event * event)11164 static void cpu_clock_event_update(struct perf_event *event)
11165 {
11166 s64 prev;
11167 u64 now;
11168
11169 now = local_clock();
11170 prev = local64_xchg(&event->hw.prev_count, now);
11171 local64_add(now - prev, &event->count);
11172 }
11173
cpu_clock_event_start(struct perf_event * event,int flags)11174 static void cpu_clock_event_start(struct perf_event *event, int flags)
11175 {
11176 local64_set(&event->hw.prev_count, local_clock());
11177 perf_swevent_start_hrtimer(event);
11178 }
11179
cpu_clock_event_stop(struct perf_event * event,int flags)11180 static void cpu_clock_event_stop(struct perf_event *event, int flags)
11181 {
11182 perf_swevent_cancel_hrtimer(event);
11183 cpu_clock_event_update(event);
11184 }
11185
cpu_clock_event_add(struct perf_event * event,int flags)11186 static int cpu_clock_event_add(struct perf_event *event, int flags)
11187 {
11188 if (flags & PERF_EF_START)
11189 cpu_clock_event_start(event, flags);
11190 perf_event_update_userpage(event);
11191
11192 return 0;
11193 }
11194
cpu_clock_event_del(struct perf_event * event,int flags)11195 static void cpu_clock_event_del(struct perf_event *event, int flags)
11196 {
11197 cpu_clock_event_stop(event, flags);
11198 }
11199
cpu_clock_event_read(struct perf_event * event)11200 static void cpu_clock_event_read(struct perf_event *event)
11201 {
11202 cpu_clock_event_update(event);
11203 }
11204
cpu_clock_event_init(struct perf_event * event)11205 static int cpu_clock_event_init(struct perf_event *event)
11206 {
11207 if (event->attr.type != perf_cpu_clock.type)
11208 return -ENOENT;
11209
11210 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
11211 return -ENOENT;
11212
11213 /*
11214 * no branch sampling for software events
11215 */
11216 if (has_branch_stack(event))
11217 return -EOPNOTSUPP;
11218
11219 perf_swevent_init_hrtimer(event);
11220
11221 return 0;
11222 }
11223
11224 static struct pmu perf_cpu_clock = {
11225 .task_ctx_nr = perf_sw_context,
11226
11227 .capabilities = PERF_PMU_CAP_NO_NMI,
11228 .dev = PMU_NULL_DEV,
11229
11230 .event_init = cpu_clock_event_init,
11231 .add = cpu_clock_event_add,
11232 .del = cpu_clock_event_del,
11233 .start = cpu_clock_event_start,
11234 .stop = cpu_clock_event_stop,
11235 .read = cpu_clock_event_read,
11236 };
11237
11238 /*
11239 * Software event: task time clock
11240 */
11241
task_clock_event_update(struct perf_event * event,u64 now)11242 static void task_clock_event_update(struct perf_event *event, u64 now)
11243 {
11244 u64 prev;
11245 s64 delta;
11246
11247 prev = local64_xchg(&event->hw.prev_count, now);
11248 delta = now - prev;
11249 local64_add(delta, &event->count);
11250 }
11251
task_clock_event_start(struct perf_event * event,int flags)11252 static void task_clock_event_start(struct perf_event *event, int flags)
11253 {
11254 local64_set(&event->hw.prev_count, event->ctx->time);
11255 perf_swevent_start_hrtimer(event);
11256 }
11257
task_clock_event_stop(struct perf_event * event,int flags)11258 static void task_clock_event_stop(struct perf_event *event, int flags)
11259 {
11260 perf_swevent_cancel_hrtimer(event);
11261 task_clock_event_update(event, event->ctx->time);
11262 }
11263
task_clock_event_add(struct perf_event * event,int flags)11264 static int task_clock_event_add(struct perf_event *event, int flags)
11265 {
11266 if (flags & PERF_EF_START)
11267 task_clock_event_start(event, flags);
11268 perf_event_update_userpage(event);
11269
11270 return 0;
11271 }
11272
task_clock_event_del(struct perf_event * event,int flags)11273 static void task_clock_event_del(struct perf_event *event, int flags)
11274 {
11275 task_clock_event_stop(event, PERF_EF_UPDATE);
11276 }
11277
task_clock_event_read(struct perf_event * event)11278 static void task_clock_event_read(struct perf_event *event)
11279 {
11280 u64 now = perf_clock();
11281 u64 delta = now - event->ctx->timestamp;
11282 u64 time = event->ctx->time + delta;
11283
11284 task_clock_event_update(event, time);
11285 }
11286
task_clock_event_init(struct perf_event * event)11287 static int task_clock_event_init(struct perf_event *event)
11288 {
11289 if (event->attr.type != perf_task_clock.type)
11290 return -ENOENT;
11291
11292 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
11293 return -ENOENT;
11294
11295 /*
11296 * no branch sampling for software events
11297 */
11298 if (has_branch_stack(event))
11299 return -EOPNOTSUPP;
11300
11301 perf_swevent_init_hrtimer(event);
11302
11303 return 0;
11304 }
11305
11306 static struct pmu perf_task_clock = {
11307 .task_ctx_nr = perf_sw_context,
11308
11309 .capabilities = PERF_PMU_CAP_NO_NMI,
11310 .dev = PMU_NULL_DEV,
11311
11312 .event_init = task_clock_event_init,
11313 .add = task_clock_event_add,
11314 .del = task_clock_event_del,
11315 .start = task_clock_event_start,
11316 .stop = task_clock_event_stop,
11317 .read = task_clock_event_read,
11318 };
11319
perf_pmu_nop_void(struct pmu * pmu)11320 static void perf_pmu_nop_void(struct pmu *pmu)
11321 {
11322 }
11323
perf_pmu_nop_txn(struct pmu * pmu,unsigned int flags)11324 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
11325 {
11326 }
11327
perf_pmu_nop_int(struct pmu * pmu)11328 static int perf_pmu_nop_int(struct pmu *pmu)
11329 {
11330 return 0;
11331 }
11332
perf_event_nop_int(struct perf_event * event,u64 value)11333 static int perf_event_nop_int(struct perf_event *event, u64 value)
11334 {
11335 return 0;
11336 }
11337
11338 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
11339
perf_pmu_start_txn(struct pmu * pmu,unsigned int flags)11340 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
11341 {
11342 __this_cpu_write(nop_txn_flags, flags);
11343
11344 if (flags & ~PERF_PMU_TXN_ADD)
11345 return;
11346
11347 perf_pmu_disable(pmu);
11348 }
11349
perf_pmu_commit_txn(struct pmu * pmu)11350 static int perf_pmu_commit_txn(struct pmu *pmu)
11351 {
11352 unsigned int flags = __this_cpu_read(nop_txn_flags);
11353
11354 __this_cpu_write(nop_txn_flags, 0);
11355
11356 if (flags & ~PERF_PMU_TXN_ADD)
11357 return 0;
11358
11359 perf_pmu_enable(pmu);
11360 return 0;
11361 }
11362
perf_pmu_cancel_txn(struct pmu * pmu)11363 static void perf_pmu_cancel_txn(struct pmu *pmu)
11364 {
11365 unsigned int flags = __this_cpu_read(nop_txn_flags);
11366
11367 __this_cpu_write(nop_txn_flags, 0);
11368
11369 if (flags & ~PERF_PMU_TXN_ADD)
11370 return;
11371
11372 perf_pmu_enable(pmu);
11373 }
11374
perf_event_idx_default(struct perf_event * event)11375 static int perf_event_idx_default(struct perf_event *event)
11376 {
11377 return 0;
11378 }
11379
free_pmu_context(struct pmu * pmu)11380 static void free_pmu_context(struct pmu *pmu)
11381 {
11382 free_percpu(pmu->cpu_pmu_context);
11383 }
11384
11385 /*
11386 * Let userspace know that this PMU supports address range filtering:
11387 */
nr_addr_filters_show(struct device * dev,struct device_attribute * attr,char * page)11388 static ssize_t nr_addr_filters_show(struct device *dev,
11389 struct device_attribute *attr,
11390 char *page)
11391 {
11392 struct pmu *pmu = dev_get_drvdata(dev);
11393
11394 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11395 }
11396 DEVICE_ATTR_RO(nr_addr_filters);
11397
11398 static struct idr pmu_idr;
11399
11400 static ssize_t
type_show(struct device * dev,struct device_attribute * attr,char * page)11401 type_show(struct device *dev, struct device_attribute *attr, char *page)
11402 {
11403 struct pmu *pmu = dev_get_drvdata(dev);
11404
11405 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
11406 }
11407 static DEVICE_ATTR_RO(type);
11408
11409 static ssize_t
perf_event_mux_interval_ms_show(struct device * dev,struct device_attribute * attr,char * page)11410 perf_event_mux_interval_ms_show(struct device *dev,
11411 struct device_attribute *attr,
11412 char *page)
11413 {
11414 struct pmu *pmu = dev_get_drvdata(dev);
11415
11416 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
11417 }
11418
11419 static DEFINE_MUTEX(mux_interval_mutex);
11420
11421 static ssize_t
perf_event_mux_interval_ms_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)11422 perf_event_mux_interval_ms_store(struct device *dev,
11423 struct device_attribute *attr,
11424 const char *buf, size_t count)
11425 {
11426 struct pmu *pmu = dev_get_drvdata(dev);
11427 int timer, cpu, ret;
11428
11429 ret = kstrtoint(buf, 0, &timer);
11430 if (ret)
11431 return ret;
11432
11433 if (timer < 1)
11434 return -EINVAL;
11435
11436 /* same value, noting to do */
11437 if (timer == pmu->hrtimer_interval_ms)
11438 return count;
11439
11440 mutex_lock(&mux_interval_mutex);
11441 pmu->hrtimer_interval_ms = timer;
11442
11443 /* update all cpuctx for this PMU */
11444 cpus_read_lock();
11445 for_each_online_cpu(cpu) {
11446 struct perf_cpu_pmu_context *cpc;
11447 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11448 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11449
11450 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc);
11451 }
11452 cpus_read_unlock();
11453 mutex_unlock(&mux_interval_mutex);
11454
11455 return count;
11456 }
11457 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11458
11459 static struct attribute *pmu_dev_attrs[] = {
11460 &dev_attr_type.attr,
11461 &dev_attr_perf_event_mux_interval_ms.attr,
11462 &dev_attr_nr_addr_filters.attr,
11463 NULL,
11464 };
11465
pmu_dev_is_visible(struct kobject * kobj,struct attribute * a,int n)11466 static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n)
11467 {
11468 struct device *dev = kobj_to_dev(kobj);
11469 struct pmu *pmu = dev_get_drvdata(dev);
11470
11471 if (n == 2 && !pmu->nr_addr_filters)
11472 return 0;
11473
11474 return a->mode;
11475 }
11476
11477 static struct attribute_group pmu_dev_attr_group = {
11478 .is_visible = pmu_dev_is_visible,
11479 .attrs = pmu_dev_attrs,
11480 };
11481
11482 static const struct attribute_group *pmu_dev_groups[] = {
11483 &pmu_dev_attr_group,
11484 NULL,
11485 };
11486
11487 static int pmu_bus_running;
11488 static struct bus_type pmu_bus = {
11489 .name = "event_source",
11490 .dev_groups = pmu_dev_groups,
11491 };
11492
pmu_dev_release(struct device * dev)11493 static void pmu_dev_release(struct device *dev)
11494 {
11495 kfree(dev);
11496 }
11497
pmu_dev_alloc(struct pmu * pmu)11498 static int pmu_dev_alloc(struct pmu *pmu)
11499 {
11500 int ret = -ENOMEM;
11501
11502 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11503 if (!pmu->dev)
11504 goto out;
11505
11506 pmu->dev->groups = pmu->attr_groups;
11507 device_initialize(pmu->dev);
11508
11509 dev_set_drvdata(pmu->dev, pmu);
11510 pmu->dev->bus = &pmu_bus;
11511 pmu->dev->parent = pmu->parent;
11512 pmu->dev->release = pmu_dev_release;
11513
11514 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11515 if (ret)
11516 goto free_dev;
11517
11518 ret = device_add(pmu->dev);
11519 if (ret)
11520 goto free_dev;
11521
11522 if (pmu->attr_update) {
11523 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11524 if (ret)
11525 goto del_dev;
11526 }
11527
11528 out:
11529 return ret;
11530
11531 del_dev:
11532 device_del(pmu->dev);
11533
11534 free_dev:
11535 put_device(pmu->dev);
11536 goto out;
11537 }
11538
11539 static struct lock_class_key cpuctx_mutex;
11540 static struct lock_class_key cpuctx_lock;
11541
perf_pmu_register(struct pmu * pmu,const char * name,int type)11542 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11543 {
11544 int cpu, ret, max = PERF_TYPE_MAX;
11545
11546 mutex_lock(&pmus_lock);
11547 ret = -ENOMEM;
11548 pmu->pmu_disable_count = alloc_percpu(int);
11549 if (!pmu->pmu_disable_count)
11550 goto unlock;
11551
11552 pmu->type = -1;
11553 if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
11554 ret = -EINVAL;
11555 goto free_pdc;
11556 }
11557
11558 pmu->name = name;
11559
11560 if (type >= 0)
11561 max = type;
11562
11563 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11564 if (ret < 0)
11565 goto free_pdc;
11566
11567 WARN_ON(type >= 0 && ret != type);
11568
11569 type = ret;
11570 pmu->type = type;
11571
11572 if (pmu_bus_running && !pmu->dev) {
11573 ret = pmu_dev_alloc(pmu);
11574 if (ret)
11575 goto free_idr;
11576 }
11577
11578 ret = -ENOMEM;
11579 pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
11580 if (!pmu->cpu_pmu_context)
11581 goto free_dev;
11582
11583 for_each_possible_cpu(cpu) {
11584 struct perf_cpu_pmu_context *cpc;
11585
11586 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11587 __perf_init_event_pmu_context(&cpc->epc, pmu);
11588 __perf_mux_hrtimer_init(cpc, cpu);
11589 }
11590
11591 if (!pmu->start_txn) {
11592 if (pmu->pmu_enable) {
11593 /*
11594 * If we have pmu_enable/pmu_disable calls, install
11595 * transaction stubs that use that to try and batch
11596 * hardware accesses.
11597 */
11598 pmu->start_txn = perf_pmu_start_txn;
11599 pmu->commit_txn = perf_pmu_commit_txn;
11600 pmu->cancel_txn = perf_pmu_cancel_txn;
11601 } else {
11602 pmu->start_txn = perf_pmu_nop_txn;
11603 pmu->commit_txn = perf_pmu_nop_int;
11604 pmu->cancel_txn = perf_pmu_nop_void;
11605 }
11606 }
11607
11608 if (!pmu->pmu_enable) {
11609 pmu->pmu_enable = perf_pmu_nop_void;
11610 pmu->pmu_disable = perf_pmu_nop_void;
11611 }
11612
11613 if (!pmu->check_period)
11614 pmu->check_period = perf_event_nop_int;
11615
11616 if (!pmu->event_idx)
11617 pmu->event_idx = perf_event_idx_default;
11618
11619 list_add_rcu(&pmu->entry, &pmus);
11620 atomic_set(&pmu->exclusive_cnt, 0);
11621 ret = 0;
11622 unlock:
11623 mutex_unlock(&pmus_lock);
11624
11625 return ret;
11626
11627 free_dev:
11628 if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
11629 device_del(pmu->dev);
11630 put_device(pmu->dev);
11631 }
11632
11633 free_idr:
11634 idr_remove(&pmu_idr, pmu->type);
11635
11636 free_pdc:
11637 free_percpu(pmu->pmu_disable_count);
11638 goto unlock;
11639 }
11640 EXPORT_SYMBOL_GPL(perf_pmu_register);
11641
perf_pmu_unregister(struct pmu * pmu)11642 void perf_pmu_unregister(struct pmu *pmu)
11643 {
11644 mutex_lock(&pmus_lock);
11645 list_del_rcu(&pmu->entry);
11646
11647 /*
11648 * We dereference the pmu list under both SRCU and regular RCU, so
11649 * synchronize against both of those.
11650 */
11651 synchronize_srcu(&pmus_srcu);
11652 synchronize_rcu();
11653
11654 free_percpu(pmu->pmu_disable_count);
11655 idr_remove(&pmu_idr, pmu->type);
11656 if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
11657 if (pmu->nr_addr_filters)
11658 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11659 device_del(pmu->dev);
11660 put_device(pmu->dev);
11661 }
11662 free_pmu_context(pmu);
11663 mutex_unlock(&pmus_lock);
11664 }
11665 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11666
has_extended_regs(struct perf_event * event)11667 static inline bool has_extended_regs(struct perf_event *event)
11668 {
11669 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11670 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11671 }
11672
perf_try_init_event(struct pmu * pmu,struct perf_event * event)11673 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11674 {
11675 struct perf_event_context *ctx = NULL;
11676 int ret;
11677
11678 if (!try_module_get(pmu->module))
11679 return -ENODEV;
11680
11681 /*
11682 * A number of pmu->event_init() methods iterate the sibling_list to,
11683 * for example, validate if the group fits on the PMU. Therefore,
11684 * if this is a sibling event, acquire the ctx->mutex to protect
11685 * the sibling_list.
11686 */
11687 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11688 /*
11689 * This ctx->mutex can nest when we're called through
11690 * inheritance. See the perf_event_ctx_lock_nested() comment.
11691 */
11692 ctx = perf_event_ctx_lock_nested(event->group_leader,
11693 SINGLE_DEPTH_NESTING);
11694 BUG_ON(!ctx);
11695 }
11696
11697 event->pmu = pmu;
11698 ret = pmu->event_init(event);
11699
11700 if (ctx)
11701 perf_event_ctx_unlock(event->group_leader, ctx);
11702
11703 if (!ret) {
11704 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11705 has_extended_regs(event))
11706 ret = -EOPNOTSUPP;
11707
11708 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11709 event_has_any_exclude_flag(event))
11710 ret = -EINVAL;
11711
11712 if (ret && event->destroy)
11713 event->destroy(event);
11714 }
11715
11716 if (ret)
11717 module_put(pmu->module);
11718
11719 return ret;
11720 }
11721
perf_init_event(struct perf_event * event)11722 static struct pmu *perf_init_event(struct perf_event *event)
11723 {
11724 bool extended_type = false;
11725 int idx, type, ret;
11726 struct pmu *pmu;
11727
11728 idx = srcu_read_lock(&pmus_srcu);
11729
11730 /*
11731 * Save original type before calling pmu->event_init() since certain
11732 * pmus overwrites event->attr.type to forward event to another pmu.
11733 */
11734 event->orig_type = event->attr.type;
11735
11736 /* Try parent's PMU first: */
11737 if (event->parent && event->parent->pmu) {
11738 pmu = event->parent->pmu;
11739 ret = perf_try_init_event(pmu, event);
11740 if (!ret)
11741 goto unlock;
11742 }
11743
11744 /*
11745 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11746 * are often aliases for PERF_TYPE_RAW.
11747 */
11748 type = event->attr.type;
11749 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11750 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11751 if (!type) {
11752 type = PERF_TYPE_RAW;
11753 } else {
11754 extended_type = true;
11755 event->attr.config &= PERF_HW_EVENT_MASK;
11756 }
11757 }
11758
11759 again:
11760 rcu_read_lock();
11761 pmu = idr_find(&pmu_idr, type);
11762 rcu_read_unlock();
11763 if (pmu) {
11764 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11765 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11766 goto fail;
11767
11768 ret = perf_try_init_event(pmu, event);
11769 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11770 type = event->attr.type;
11771 goto again;
11772 }
11773
11774 if (ret)
11775 pmu = ERR_PTR(ret);
11776
11777 goto unlock;
11778 }
11779
11780 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11781 ret = perf_try_init_event(pmu, event);
11782 if (!ret)
11783 goto unlock;
11784
11785 if (ret != -ENOENT) {
11786 pmu = ERR_PTR(ret);
11787 goto unlock;
11788 }
11789 }
11790 fail:
11791 pmu = ERR_PTR(-ENOENT);
11792 unlock:
11793 srcu_read_unlock(&pmus_srcu, idx);
11794
11795 return pmu;
11796 }
11797
attach_sb_event(struct perf_event * event)11798 static void attach_sb_event(struct perf_event *event)
11799 {
11800 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11801
11802 raw_spin_lock(&pel->lock);
11803 list_add_rcu(&event->sb_list, &pel->list);
11804 raw_spin_unlock(&pel->lock);
11805 }
11806
11807 /*
11808 * We keep a list of all !task (and therefore per-cpu) events
11809 * that need to receive side-band records.
11810 *
11811 * This avoids having to scan all the various PMU per-cpu contexts
11812 * looking for them.
11813 */
account_pmu_sb_event(struct perf_event * event)11814 static void account_pmu_sb_event(struct perf_event *event)
11815 {
11816 if (is_sb_event(event))
11817 attach_sb_event(event);
11818 }
11819
11820 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
account_freq_event_nohz(void)11821 static void account_freq_event_nohz(void)
11822 {
11823 #ifdef CONFIG_NO_HZ_FULL
11824 /* Lock so we don't race with concurrent unaccount */
11825 spin_lock(&nr_freq_lock);
11826 if (atomic_inc_return(&nr_freq_events) == 1)
11827 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11828 spin_unlock(&nr_freq_lock);
11829 #endif
11830 }
11831
account_freq_event(void)11832 static void account_freq_event(void)
11833 {
11834 if (tick_nohz_full_enabled())
11835 account_freq_event_nohz();
11836 else
11837 atomic_inc(&nr_freq_events);
11838 }
11839
11840
account_event(struct perf_event * event)11841 static void account_event(struct perf_event *event)
11842 {
11843 bool inc = false;
11844
11845 if (event->parent)
11846 return;
11847
11848 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11849 inc = true;
11850 if (event->attr.mmap || event->attr.mmap_data)
11851 atomic_inc(&nr_mmap_events);
11852 if (event->attr.build_id)
11853 atomic_inc(&nr_build_id_events);
11854 if (event->attr.comm)
11855 atomic_inc(&nr_comm_events);
11856 if (event->attr.namespaces)
11857 atomic_inc(&nr_namespaces_events);
11858 if (event->attr.cgroup)
11859 atomic_inc(&nr_cgroup_events);
11860 if (event->attr.task)
11861 atomic_inc(&nr_task_events);
11862 if (event->attr.freq)
11863 account_freq_event();
11864 if (event->attr.context_switch) {
11865 atomic_inc(&nr_switch_events);
11866 inc = true;
11867 }
11868 if (has_branch_stack(event))
11869 inc = true;
11870 if (is_cgroup_event(event))
11871 inc = true;
11872 if (event->attr.ksymbol)
11873 atomic_inc(&nr_ksymbol_events);
11874 if (event->attr.bpf_event)
11875 atomic_inc(&nr_bpf_events);
11876 if (event->attr.text_poke)
11877 atomic_inc(&nr_text_poke_events);
11878
11879 if (inc) {
11880 /*
11881 * We need the mutex here because static_branch_enable()
11882 * must complete *before* the perf_sched_count increment
11883 * becomes visible.
11884 */
11885 if (atomic_inc_not_zero(&perf_sched_count))
11886 goto enabled;
11887
11888 mutex_lock(&perf_sched_mutex);
11889 if (!atomic_read(&perf_sched_count)) {
11890 static_branch_enable(&perf_sched_events);
11891 /*
11892 * Guarantee that all CPUs observe they key change and
11893 * call the perf scheduling hooks before proceeding to
11894 * install events that need them.
11895 */
11896 synchronize_rcu();
11897 }
11898 /*
11899 * Now that we have waited for the sync_sched(), allow further
11900 * increments to by-pass the mutex.
11901 */
11902 atomic_inc(&perf_sched_count);
11903 mutex_unlock(&perf_sched_mutex);
11904 }
11905 enabled:
11906
11907 account_pmu_sb_event(event);
11908 }
11909
11910 /*
11911 * Allocate and initialize an event structure
11912 */
11913 static struct perf_event *
perf_event_alloc(struct perf_event_attr * attr,int cpu,struct task_struct * task,struct perf_event * group_leader,struct perf_event * parent_event,perf_overflow_handler_t overflow_handler,void * context,int cgroup_fd)11914 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11915 struct task_struct *task,
11916 struct perf_event *group_leader,
11917 struct perf_event *parent_event,
11918 perf_overflow_handler_t overflow_handler,
11919 void *context, int cgroup_fd)
11920 {
11921 struct pmu *pmu;
11922 struct perf_event *event;
11923 struct hw_perf_event *hwc;
11924 long err = -EINVAL;
11925 int node;
11926
11927 if ((unsigned)cpu >= nr_cpu_ids) {
11928 if (!task || cpu != -1)
11929 return ERR_PTR(-EINVAL);
11930 }
11931 if (attr->sigtrap && !task) {
11932 /* Requires a task: avoid signalling random tasks. */
11933 return ERR_PTR(-EINVAL);
11934 }
11935
11936 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11937 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11938 node);
11939 if (!event)
11940 return ERR_PTR(-ENOMEM);
11941
11942 /*
11943 * Single events are their own group leaders, with an
11944 * empty sibling list:
11945 */
11946 if (!group_leader)
11947 group_leader = event;
11948
11949 mutex_init(&event->child_mutex);
11950 INIT_LIST_HEAD(&event->child_list);
11951
11952 INIT_LIST_HEAD(&event->event_entry);
11953 INIT_LIST_HEAD(&event->sibling_list);
11954 INIT_LIST_HEAD(&event->active_list);
11955 init_event_group(event);
11956 INIT_LIST_HEAD(&event->rb_entry);
11957 INIT_LIST_HEAD(&event->active_entry);
11958 INIT_LIST_HEAD(&event->addr_filters.list);
11959 INIT_HLIST_NODE(&event->hlist_entry);
11960
11961
11962 init_waitqueue_head(&event->waitq);
11963 init_irq_work(&event->pending_irq, perf_pending_irq);
11964 init_task_work(&event->pending_task, perf_pending_task);
11965
11966 mutex_init(&event->mmap_mutex);
11967 raw_spin_lock_init(&event->addr_filters.lock);
11968
11969 atomic_long_set(&event->refcount, 1);
11970 event->cpu = cpu;
11971 event->attr = *attr;
11972 event->group_leader = group_leader;
11973 event->pmu = NULL;
11974 event->oncpu = -1;
11975
11976 event->parent = parent_event;
11977
11978 event->ns = get_pid_ns(task_active_pid_ns(current));
11979 event->id = atomic64_inc_return(&perf_event_id);
11980
11981 event->state = PERF_EVENT_STATE_INACTIVE;
11982
11983 if (parent_event)
11984 event->event_caps = parent_event->event_caps;
11985
11986 if (task) {
11987 event->attach_state = PERF_ATTACH_TASK;
11988 /*
11989 * XXX pmu::event_init needs to know what task to account to
11990 * and we cannot use the ctx information because we need the
11991 * pmu before we get a ctx.
11992 */
11993 event->hw.target = get_task_struct(task);
11994 }
11995
11996 event->clock = &local_clock;
11997 if (parent_event)
11998 event->clock = parent_event->clock;
11999
12000 if (!overflow_handler && parent_event) {
12001 overflow_handler = parent_event->overflow_handler;
12002 context = parent_event->overflow_handler_context;
12003 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
12004 if (parent_event->prog) {
12005 struct bpf_prog *prog = parent_event->prog;
12006
12007 bpf_prog_inc(prog);
12008 event->prog = prog;
12009 }
12010 #endif
12011 }
12012
12013 if (overflow_handler) {
12014 event->overflow_handler = overflow_handler;
12015 event->overflow_handler_context = context;
12016 } else if (is_write_backward(event)){
12017 event->overflow_handler = perf_event_output_backward;
12018 event->overflow_handler_context = NULL;
12019 } else {
12020 event->overflow_handler = perf_event_output_forward;
12021 event->overflow_handler_context = NULL;
12022 }
12023
12024 perf_event__state_init(event);
12025
12026 pmu = NULL;
12027
12028 hwc = &event->hw;
12029 hwc->sample_period = attr->sample_period;
12030 if (attr->freq && attr->sample_freq)
12031 hwc->sample_period = 1;
12032 hwc->last_period = hwc->sample_period;
12033
12034 local64_set(&hwc->period_left, hwc->sample_period);
12035
12036 /*
12037 * We currently do not support PERF_SAMPLE_READ on inherited events.
12038 * See perf_output_read().
12039 */
12040 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
12041 goto err_ns;
12042
12043 if (!has_branch_stack(event))
12044 event->attr.branch_sample_type = 0;
12045
12046 pmu = perf_init_event(event);
12047 if (IS_ERR(pmu)) {
12048 err = PTR_ERR(pmu);
12049 goto err_ns;
12050 }
12051
12052 /*
12053 * Disallow uncore-task events. Similarly, disallow uncore-cgroup
12054 * events (they don't make sense as the cgroup will be different
12055 * on other CPUs in the uncore mask).
12056 */
12057 if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {
12058 err = -EINVAL;
12059 goto err_pmu;
12060 }
12061
12062 if (event->attr.aux_output &&
12063 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
12064 err = -EOPNOTSUPP;
12065 goto err_pmu;
12066 }
12067
12068 if (cgroup_fd != -1) {
12069 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
12070 if (err)
12071 goto err_pmu;
12072 }
12073
12074 err = exclusive_event_init(event);
12075 if (err)
12076 goto err_pmu;
12077
12078 if (has_addr_filter(event)) {
12079 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
12080 sizeof(struct perf_addr_filter_range),
12081 GFP_KERNEL);
12082 if (!event->addr_filter_ranges) {
12083 err = -ENOMEM;
12084 goto err_per_task;
12085 }
12086
12087 /*
12088 * Clone the parent's vma offsets: they are valid until exec()
12089 * even if the mm is not shared with the parent.
12090 */
12091 if (event->parent) {
12092 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
12093
12094 raw_spin_lock_irq(&ifh->lock);
12095 memcpy(event->addr_filter_ranges,
12096 event->parent->addr_filter_ranges,
12097 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
12098 raw_spin_unlock_irq(&ifh->lock);
12099 }
12100
12101 /* force hw sync on the address filters */
12102 event->addr_filters_gen = 1;
12103 }
12104
12105 if (!event->parent) {
12106 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
12107 err = get_callchain_buffers(attr->sample_max_stack);
12108 if (err)
12109 goto err_addr_filters;
12110 }
12111 }
12112
12113 err = security_perf_event_alloc(event);
12114 if (err)
12115 goto err_callchain_buffer;
12116
12117 /* symmetric to unaccount_event() in _free_event() */
12118 account_event(event);
12119
12120 return event;
12121
12122 err_callchain_buffer:
12123 if (!event->parent) {
12124 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
12125 put_callchain_buffers();
12126 }
12127 err_addr_filters:
12128 kfree(event->addr_filter_ranges);
12129
12130 err_per_task:
12131 exclusive_event_destroy(event);
12132
12133 err_pmu:
12134 if (is_cgroup_event(event))
12135 perf_detach_cgroup(event);
12136 if (event->destroy)
12137 event->destroy(event);
12138 module_put(pmu->module);
12139 err_ns:
12140 if (event->hw.target)
12141 put_task_struct(event->hw.target);
12142 call_rcu(&event->rcu_head, free_event_rcu);
12143
12144 return ERR_PTR(err);
12145 }
12146
perf_copy_attr(struct perf_event_attr __user * uattr,struct perf_event_attr * attr)12147 static int perf_copy_attr(struct perf_event_attr __user *uattr,
12148 struct perf_event_attr *attr)
12149 {
12150 u32 size;
12151 int ret;
12152
12153 /* Zero the full structure, so that a short copy will be nice. */
12154 memset(attr, 0, sizeof(*attr));
12155
12156 ret = get_user(size, &uattr->size);
12157 if (ret)
12158 return ret;
12159
12160 /* ABI compatibility quirk: */
12161 if (!size)
12162 size = PERF_ATTR_SIZE_VER0;
12163 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
12164 goto err_size;
12165
12166 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
12167 if (ret) {
12168 if (ret == -E2BIG)
12169 goto err_size;
12170 return ret;
12171 }
12172
12173 attr->size = size;
12174
12175 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
12176 return -EINVAL;
12177
12178 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
12179 return -EINVAL;
12180
12181 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
12182 return -EINVAL;
12183
12184 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
12185 u64 mask = attr->branch_sample_type;
12186
12187 /* only using defined bits */
12188 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
12189 return -EINVAL;
12190
12191 /* at least one branch bit must be set */
12192 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
12193 return -EINVAL;
12194
12195 /* propagate priv level, when not set for branch */
12196 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
12197
12198 /* exclude_kernel checked on syscall entry */
12199 if (!attr->exclude_kernel)
12200 mask |= PERF_SAMPLE_BRANCH_KERNEL;
12201
12202 if (!attr->exclude_user)
12203 mask |= PERF_SAMPLE_BRANCH_USER;
12204
12205 if (!attr->exclude_hv)
12206 mask |= PERF_SAMPLE_BRANCH_HV;
12207 /*
12208 * adjust user setting (for HW filter setup)
12209 */
12210 attr->branch_sample_type = mask;
12211 }
12212 /* privileged levels capture (kernel, hv): check permissions */
12213 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
12214 ret = perf_allow_kernel(attr);
12215 if (ret)
12216 return ret;
12217 }
12218 }
12219
12220 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
12221 ret = perf_reg_validate(attr->sample_regs_user);
12222 if (ret)
12223 return ret;
12224 }
12225
12226 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
12227 if (!arch_perf_have_user_stack_dump())
12228 return -ENOSYS;
12229
12230 /*
12231 * We have __u32 type for the size, but so far
12232 * we can only use __u16 as maximum due to the
12233 * __u16 sample size limit.
12234 */
12235 if (attr->sample_stack_user >= USHRT_MAX)
12236 return -EINVAL;
12237 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
12238 return -EINVAL;
12239 }
12240
12241 if (!attr->sample_max_stack)
12242 attr->sample_max_stack = sysctl_perf_event_max_stack;
12243
12244 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
12245 ret = perf_reg_validate(attr->sample_regs_intr);
12246
12247 #ifndef CONFIG_CGROUP_PERF
12248 if (attr->sample_type & PERF_SAMPLE_CGROUP)
12249 return -EINVAL;
12250 #endif
12251 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
12252 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
12253 return -EINVAL;
12254
12255 if (!attr->inherit && attr->inherit_thread)
12256 return -EINVAL;
12257
12258 if (attr->remove_on_exec && attr->enable_on_exec)
12259 return -EINVAL;
12260
12261 if (attr->sigtrap && !attr->remove_on_exec)
12262 return -EINVAL;
12263
12264 out:
12265 return ret;
12266
12267 err_size:
12268 put_user(sizeof(*attr), &uattr->size);
12269 ret = -E2BIG;
12270 goto out;
12271 }
12272
mutex_lock_double(struct mutex * a,struct mutex * b)12273 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12274 {
12275 if (b < a)
12276 swap(a, b);
12277
12278 mutex_lock(a);
12279 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12280 }
12281
12282 static int
perf_event_set_output(struct perf_event * event,struct perf_event * output_event)12283 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
12284 {
12285 struct perf_buffer *rb = NULL;
12286 int ret = -EINVAL;
12287
12288 if (!output_event) {
12289 mutex_lock(&event->mmap_mutex);
12290 goto set;
12291 }
12292
12293 /* don't allow circular references */
12294 if (event == output_event)
12295 goto out;
12296
12297 /*
12298 * Don't allow cross-cpu buffers
12299 */
12300 if (output_event->cpu != event->cpu)
12301 goto out;
12302
12303 /*
12304 * If its not a per-cpu rb, it must be the same task.
12305 */
12306 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
12307 goto out;
12308
12309 /*
12310 * Mixing clocks in the same buffer is trouble you don't need.
12311 */
12312 if (output_event->clock != event->clock)
12313 goto out;
12314
12315 /*
12316 * Either writing ring buffer from beginning or from end.
12317 * Mixing is not allowed.
12318 */
12319 if (is_write_backward(output_event) != is_write_backward(event))
12320 goto out;
12321
12322 /*
12323 * If both events generate aux data, they must be on the same PMU
12324 */
12325 if (has_aux(event) && has_aux(output_event) &&
12326 event->pmu != output_event->pmu)
12327 goto out;
12328
12329 /*
12330 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
12331 * output_event is already on rb->event_list, and the list iteration
12332 * restarts after every removal, it is guaranteed this new event is
12333 * observed *OR* if output_event is already removed, it's guaranteed we
12334 * observe !rb->mmap_count.
12335 */
12336 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
12337 set:
12338 /* Can't redirect output if we've got an active mmap() */
12339 if (atomic_read(&event->mmap_count))
12340 goto unlock;
12341
12342 if (output_event) {
12343 /* get the rb we want to redirect to */
12344 rb = ring_buffer_get(output_event);
12345 if (!rb)
12346 goto unlock;
12347
12348 /* did we race against perf_mmap_close() */
12349 if (!atomic_read(&rb->mmap_count)) {
12350 ring_buffer_put(rb);
12351 goto unlock;
12352 }
12353 }
12354
12355 ring_buffer_attach(event, rb);
12356
12357 ret = 0;
12358 unlock:
12359 mutex_unlock(&event->mmap_mutex);
12360 if (output_event)
12361 mutex_unlock(&output_event->mmap_mutex);
12362
12363 out:
12364 return ret;
12365 }
12366
perf_event_set_clock(struct perf_event * event,clockid_t clk_id)12367 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12368 {
12369 bool nmi_safe = false;
12370
12371 switch (clk_id) {
12372 case CLOCK_MONOTONIC:
12373 event->clock = &ktime_get_mono_fast_ns;
12374 nmi_safe = true;
12375 break;
12376
12377 case CLOCK_MONOTONIC_RAW:
12378 event->clock = &ktime_get_raw_fast_ns;
12379 nmi_safe = true;
12380 break;
12381
12382 case CLOCK_REALTIME:
12383 event->clock = &ktime_get_real_ns;
12384 break;
12385
12386 case CLOCK_BOOTTIME:
12387 event->clock = &ktime_get_boottime_ns;
12388 break;
12389
12390 case CLOCK_TAI:
12391 event->clock = &ktime_get_clocktai_ns;
12392 break;
12393
12394 default:
12395 return -EINVAL;
12396 }
12397
12398 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12399 return -EINVAL;
12400
12401 return 0;
12402 }
12403
12404 static bool
perf_check_permission(struct perf_event_attr * attr,struct task_struct * task)12405 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12406 {
12407 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12408 bool is_capable = perfmon_capable();
12409
12410 if (attr->sigtrap) {
12411 /*
12412 * perf_event_attr::sigtrap sends signals to the other task.
12413 * Require the current task to also have CAP_KILL.
12414 */
12415 rcu_read_lock();
12416 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12417 rcu_read_unlock();
12418
12419 /*
12420 * If the required capabilities aren't available, checks for
12421 * ptrace permissions: upgrade to ATTACH, since sending signals
12422 * can effectively change the target task.
12423 */
12424 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12425 }
12426
12427 /*
12428 * Preserve ptrace permission check for backwards compatibility. The
12429 * ptrace check also includes checks that the current task and other
12430 * task have matching uids, and is therefore not done here explicitly.
12431 */
12432 return is_capable || ptrace_may_access(task, ptrace_mode);
12433 }
12434
12435 /**
12436 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12437 *
12438 * @attr_uptr: event_id type attributes for monitoring/sampling
12439 * @pid: target pid
12440 * @cpu: target cpu
12441 * @group_fd: group leader event fd
12442 * @flags: perf event open flags
12443 */
SYSCALL_DEFINE5(perf_event_open,struct perf_event_attr __user *,attr_uptr,pid_t,pid,int,cpu,int,group_fd,unsigned long,flags)12444 SYSCALL_DEFINE5(perf_event_open,
12445 struct perf_event_attr __user *, attr_uptr,
12446 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12447 {
12448 struct perf_event *group_leader = NULL, *output_event = NULL;
12449 struct perf_event_pmu_context *pmu_ctx;
12450 struct perf_event *event, *sibling;
12451 struct perf_event_attr attr;
12452 struct perf_event_context *ctx;
12453 struct file *event_file = NULL;
12454 struct fd group = {NULL, 0};
12455 struct task_struct *task = NULL;
12456 struct pmu *pmu;
12457 int event_fd;
12458 int move_group = 0;
12459 int err;
12460 int f_flags = O_RDWR;
12461 int cgroup_fd = -1;
12462
12463 /* for future expandability... */
12464 if (flags & ~PERF_FLAG_ALL)
12465 return -EINVAL;
12466
12467 err = perf_copy_attr(attr_uptr, &attr);
12468 if (err)
12469 return err;
12470
12471 /* Do we allow access to perf_event_open(2) ? */
12472 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12473 if (err)
12474 return err;
12475
12476 if (!attr.exclude_kernel) {
12477 err = perf_allow_kernel(&attr);
12478 if (err)
12479 return err;
12480 }
12481
12482 if (attr.namespaces) {
12483 if (!perfmon_capable())
12484 return -EACCES;
12485 }
12486
12487 if (attr.freq) {
12488 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12489 return -EINVAL;
12490 } else {
12491 if (attr.sample_period & (1ULL << 63))
12492 return -EINVAL;
12493 }
12494
12495 /* Only privileged users can get physical addresses */
12496 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12497 err = perf_allow_kernel(&attr);
12498 if (err)
12499 return err;
12500 }
12501
12502 /* REGS_INTR can leak data, lockdown must prevent this */
12503 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12504 err = security_locked_down(LOCKDOWN_PERF);
12505 if (err)
12506 return err;
12507 }
12508
12509 /*
12510 * In cgroup mode, the pid argument is used to pass the fd
12511 * opened to the cgroup directory in cgroupfs. The cpu argument
12512 * designates the cpu on which to monitor threads from that
12513 * cgroup.
12514 */
12515 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12516 return -EINVAL;
12517
12518 if (flags & PERF_FLAG_FD_CLOEXEC)
12519 f_flags |= O_CLOEXEC;
12520
12521 event_fd = get_unused_fd_flags(f_flags);
12522 if (event_fd < 0)
12523 return event_fd;
12524
12525 if (group_fd != -1) {
12526 err = perf_fget_light(group_fd, &group);
12527 if (err)
12528 goto err_fd;
12529 group_leader = group.file->private_data;
12530 if (flags & PERF_FLAG_FD_OUTPUT)
12531 output_event = group_leader;
12532 if (flags & PERF_FLAG_FD_NO_GROUP)
12533 group_leader = NULL;
12534 }
12535
12536 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12537 task = find_lively_task_by_vpid(pid);
12538 if (IS_ERR(task)) {
12539 err = PTR_ERR(task);
12540 goto err_group_fd;
12541 }
12542 }
12543
12544 if (task && group_leader &&
12545 group_leader->attr.inherit != attr.inherit) {
12546 err = -EINVAL;
12547 goto err_task;
12548 }
12549
12550 if (flags & PERF_FLAG_PID_CGROUP)
12551 cgroup_fd = pid;
12552
12553 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12554 NULL, NULL, cgroup_fd);
12555 if (IS_ERR(event)) {
12556 err = PTR_ERR(event);
12557 goto err_task;
12558 }
12559
12560 if (is_sampling_event(event)) {
12561 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12562 err = -EOPNOTSUPP;
12563 goto err_alloc;
12564 }
12565 }
12566
12567 /*
12568 * Special case software events and allow them to be part of
12569 * any hardware group.
12570 */
12571 pmu = event->pmu;
12572
12573 if (attr.use_clockid) {
12574 err = perf_event_set_clock(event, attr.clockid);
12575 if (err)
12576 goto err_alloc;
12577 }
12578
12579 if (pmu->task_ctx_nr == perf_sw_context)
12580 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12581
12582 if (task) {
12583 err = down_read_interruptible(&task->signal->exec_update_lock);
12584 if (err)
12585 goto err_alloc;
12586
12587 /*
12588 * We must hold exec_update_lock across this and any potential
12589 * perf_install_in_context() call for this new event to
12590 * serialize against exec() altering our credentials (and the
12591 * perf_event_exit_task() that could imply).
12592 */
12593 err = -EACCES;
12594 if (!perf_check_permission(&attr, task))
12595 goto err_cred;
12596 }
12597
12598 /*
12599 * Get the target context (task or percpu):
12600 */
12601 ctx = find_get_context(task, event);
12602 if (IS_ERR(ctx)) {
12603 err = PTR_ERR(ctx);
12604 goto err_cred;
12605 }
12606
12607 mutex_lock(&ctx->mutex);
12608
12609 if (ctx->task == TASK_TOMBSTONE) {
12610 err = -ESRCH;
12611 goto err_locked;
12612 }
12613
12614 if (!task) {
12615 /*
12616 * Check if the @cpu we're creating an event for is online.
12617 *
12618 * We use the perf_cpu_context::ctx::mutex to serialize against
12619 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12620 */
12621 struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
12622
12623 if (!cpuctx->online) {
12624 err = -ENODEV;
12625 goto err_locked;
12626 }
12627 }
12628
12629 if (group_leader) {
12630 err = -EINVAL;
12631
12632 /*
12633 * Do not allow a recursive hierarchy (this new sibling
12634 * becoming part of another group-sibling):
12635 */
12636 if (group_leader->group_leader != group_leader)
12637 goto err_locked;
12638
12639 /* All events in a group should have the same clock */
12640 if (group_leader->clock != event->clock)
12641 goto err_locked;
12642
12643 /*
12644 * Make sure we're both events for the same CPU;
12645 * grouping events for different CPUs is broken; since
12646 * you can never concurrently schedule them anyhow.
12647 */
12648 if (group_leader->cpu != event->cpu)
12649 goto err_locked;
12650
12651 /*
12652 * Make sure we're both on the same context; either task or cpu.
12653 */
12654 if (group_leader->ctx != ctx)
12655 goto err_locked;
12656
12657 /*
12658 * Only a group leader can be exclusive or pinned
12659 */
12660 if (attr.exclusive || attr.pinned)
12661 goto err_locked;
12662
12663 if (is_software_event(event) &&
12664 !in_software_context(group_leader)) {
12665 /*
12666 * If the event is a sw event, but the group_leader
12667 * is on hw context.
12668 *
12669 * Allow the addition of software events to hw
12670 * groups, this is safe because software events
12671 * never fail to schedule.
12672 *
12673 * Note the comment that goes with struct
12674 * perf_event_pmu_context.
12675 */
12676 pmu = group_leader->pmu_ctx->pmu;
12677 } else if (!is_software_event(event)) {
12678 if (is_software_event(group_leader) &&
12679 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12680 /*
12681 * In case the group is a pure software group, and we
12682 * try to add a hardware event, move the whole group to
12683 * the hardware context.
12684 */
12685 move_group = 1;
12686 }
12687
12688 /* Don't allow group of multiple hw events from different pmus */
12689 if (!in_software_context(group_leader) &&
12690 group_leader->pmu_ctx->pmu != pmu)
12691 goto err_locked;
12692 }
12693 }
12694
12695 /*
12696 * Now that we're certain of the pmu; find the pmu_ctx.
12697 */
12698 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12699 if (IS_ERR(pmu_ctx)) {
12700 err = PTR_ERR(pmu_ctx);
12701 goto err_locked;
12702 }
12703 event->pmu_ctx = pmu_ctx;
12704
12705 if (output_event) {
12706 err = perf_event_set_output(event, output_event);
12707 if (err)
12708 goto err_context;
12709 }
12710
12711 if (!perf_event_validate_size(event)) {
12712 err = -E2BIG;
12713 goto err_context;
12714 }
12715
12716 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12717 err = -EINVAL;
12718 goto err_context;
12719 }
12720
12721 /*
12722 * Must be under the same ctx::mutex as perf_install_in_context(),
12723 * because we need to serialize with concurrent event creation.
12724 */
12725 if (!exclusive_event_installable(event, ctx)) {
12726 err = -EBUSY;
12727 goto err_context;
12728 }
12729
12730 WARN_ON_ONCE(ctx->parent_ctx);
12731
12732 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags);
12733 if (IS_ERR(event_file)) {
12734 err = PTR_ERR(event_file);
12735 event_file = NULL;
12736 goto err_context;
12737 }
12738
12739 /*
12740 * This is the point on no return; we cannot fail hereafter. This is
12741 * where we start modifying current state.
12742 */
12743
12744 if (move_group) {
12745 perf_remove_from_context(group_leader, 0);
12746 put_pmu_ctx(group_leader->pmu_ctx);
12747
12748 for_each_sibling_event(sibling, group_leader) {
12749 perf_remove_from_context(sibling, 0);
12750 put_pmu_ctx(sibling->pmu_ctx);
12751 }
12752
12753 /*
12754 * Install the group siblings before the group leader.
12755 *
12756 * Because a group leader will try and install the entire group
12757 * (through the sibling list, which is still in-tact), we can
12758 * end up with siblings installed in the wrong context.
12759 *
12760 * By installing siblings first we NO-OP because they're not
12761 * reachable through the group lists.
12762 */
12763 for_each_sibling_event(sibling, group_leader) {
12764 sibling->pmu_ctx = pmu_ctx;
12765 get_pmu_ctx(pmu_ctx);
12766 perf_event__state_init(sibling);
12767 perf_install_in_context(ctx, sibling, sibling->cpu);
12768 }
12769
12770 /*
12771 * Removing from the context ends up with disabled
12772 * event. What we want here is event in the initial
12773 * startup state, ready to be add into new context.
12774 */
12775 group_leader->pmu_ctx = pmu_ctx;
12776 get_pmu_ctx(pmu_ctx);
12777 perf_event__state_init(group_leader);
12778 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12779 }
12780
12781 /*
12782 * Precalculate sample_data sizes; do while holding ctx::mutex such
12783 * that we're serialized against further additions and before
12784 * perf_install_in_context() which is the point the event is active and
12785 * can use these values.
12786 */
12787 perf_event__header_size(event);
12788 perf_event__id_header_size(event);
12789
12790 event->owner = current;
12791
12792 perf_install_in_context(ctx, event, event->cpu);
12793 perf_unpin_context(ctx);
12794
12795 mutex_unlock(&ctx->mutex);
12796
12797 if (task) {
12798 up_read(&task->signal->exec_update_lock);
12799 put_task_struct(task);
12800 }
12801
12802 mutex_lock(¤t->perf_event_mutex);
12803 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12804 mutex_unlock(¤t->perf_event_mutex);
12805
12806 /*
12807 * Drop the reference on the group_event after placing the
12808 * new event on the sibling_list. This ensures destruction
12809 * of the group leader will find the pointer to itself in
12810 * perf_group_detach().
12811 */
12812 fdput(group);
12813 fd_install(event_fd, event_file);
12814 return event_fd;
12815
12816 err_context:
12817 put_pmu_ctx(event->pmu_ctx);
12818 event->pmu_ctx = NULL; /* _free_event() */
12819 err_locked:
12820 mutex_unlock(&ctx->mutex);
12821 perf_unpin_context(ctx);
12822 put_ctx(ctx);
12823 err_cred:
12824 if (task)
12825 up_read(&task->signal->exec_update_lock);
12826 err_alloc:
12827 free_event(event);
12828 err_task:
12829 if (task)
12830 put_task_struct(task);
12831 err_group_fd:
12832 fdput(group);
12833 err_fd:
12834 put_unused_fd(event_fd);
12835 return err;
12836 }
12837
12838 /**
12839 * perf_event_create_kernel_counter
12840 *
12841 * @attr: attributes of the counter to create
12842 * @cpu: cpu in which the counter is bound
12843 * @task: task to profile (NULL for percpu)
12844 * @overflow_handler: callback to trigger when we hit the event
12845 * @context: context data could be used in overflow_handler callback
12846 */
12847 struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr * attr,int cpu,struct task_struct * task,perf_overflow_handler_t overflow_handler,void * context)12848 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12849 struct task_struct *task,
12850 perf_overflow_handler_t overflow_handler,
12851 void *context)
12852 {
12853 struct perf_event_pmu_context *pmu_ctx;
12854 struct perf_event_context *ctx;
12855 struct perf_event *event;
12856 struct pmu *pmu;
12857 int err;
12858
12859 /*
12860 * Grouping is not supported for kernel events, neither is 'AUX',
12861 * make sure the caller's intentions are adjusted.
12862 */
12863 if (attr->aux_output)
12864 return ERR_PTR(-EINVAL);
12865
12866 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12867 overflow_handler, context, -1);
12868 if (IS_ERR(event)) {
12869 err = PTR_ERR(event);
12870 goto err;
12871 }
12872
12873 /* Mark owner so we could distinguish it from user events. */
12874 event->owner = TASK_TOMBSTONE;
12875 pmu = event->pmu;
12876
12877 if (pmu->task_ctx_nr == perf_sw_context)
12878 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12879
12880 /*
12881 * Get the target context (task or percpu):
12882 */
12883 ctx = find_get_context(task, event);
12884 if (IS_ERR(ctx)) {
12885 err = PTR_ERR(ctx);
12886 goto err_alloc;
12887 }
12888
12889 WARN_ON_ONCE(ctx->parent_ctx);
12890 mutex_lock(&ctx->mutex);
12891 if (ctx->task == TASK_TOMBSTONE) {
12892 err = -ESRCH;
12893 goto err_unlock;
12894 }
12895
12896 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12897 if (IS_ERR(pmu_ctx)) {
12898 err = PTR_ERR(pmu_ctx);
12899 goto err_unlock;
12900 }
12901 event->pmu_ctx = pmu_ctx;
12902
12903 if (!task) {
12904 /*
12905 * Check if the @cpu we're creating an event for is online.
12906 *
12907 * We use the perf_cpu_context::ctx::mutex to serialize against
12908 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12909 */
12910 struct perf_cpu_context *cpuctx =
12911 container_of(ctx, struct perf_cpu_context, ctx);
12912 if (!cpuctx->online) {
12913 err = -ENODEV;
12914 goto err_pmu_ctx;
12915 }
12916 }
12917
12918 if (!exclusive_event_installable(event, ctx)) {
12919 err = -EBUSY;
12920 goto err_pmu_ctx;
12921 }
12922
12923 perf_install_in_context(ctx, event, event->cpu);
12924 perf_unpin_context(ctx);
12925 mutex_unlock(&ctx->mutex);
12926
12927 return event;
12928
12929 err_pmu_ctx:
12930 put_pmu_ctx(pmu_ctx);
12931 event->pmu_ctx = NULL; /* _free_event() */
12932 err_unlock:
12933 mutex_unlock(&ctx->mutex);
12934 perf_unpin_context(ctx);
12935 put_ctx(ctx);
12936 err_alloc:
12937 free_event(event);
12938 err:
12939 return ERR_PTR(err);
12940 }
12941 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12942
__perf_pmu_remove(struct perf_event_context * ctx,int cpu,struct pmu * pmu,struct perf_event_groups * groups,struct list_head * events)12943 static void __perf_pmu_remove(struct perf_event_context *ctx,
12944 int cpu, struct pmu *pmu,
12945 struct perf_event_groups *groups,
12946 struct list_head *events)
12947 {
12948 struct perf_event *event, *sibling;
12949
12950 perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
12951 perf_remove_from_context(event, 0);
12952 put_pmu_ctx(event->pmu_ctx);
12953 list_add(&event->migrate_entry, events);
12954
12955 for_each_sibling_event(sibling, event) {
12956 perf_remove_from_context(sibling, 0);
12957 put_pmu_ctx(sibling->pmu_ctx);
12958 list_add(&sibling->migrate_entry, events);
12959 }
12960 }
12961 }
12962
__perf_pmu_install_event(struct pmu * pmu,struct perf_event_context * ctx,int cpu,struct perf_event * event)12963 static void __perf_pmu_install_event(struct pmu *pmu,
12964 struct perf_event_context *ctx,
12965 int cpu, struct perf_event *event)
12966 {
12967 struct perf_event_pmu_context *epc;
12968 struct perf_event_context *old_ctx = event->ctx;
12969
12970 get_ctx(ctx); /* normally find_get_context() */
12971
12972 event->cpu = cpu;
12973 epc = find_get_pmu_context(pmu, ctx, event);
12974 event->pmu_ctx = epc;
12975
12976 if (event->state >= PERF_EVENT_STATE_OFF)
12977 event->state = PERF_EVENT_STATE_INACTIVE;
12978 perf_install_in_context(ctx, event, cpu);
12979
12980 /*
12981 * Now that event->ctx is updated and visible, put the old ctx.
12982 */
12983 put_ctx(old_ctx);
12984 }
12985
__perf_pmu_install(struct perf_event_context * ctx,int cpu,struct pmu * pmu,struct list_head * events)12986 static void __perf_pmu_install(struct perf_event_context *ctx,
12987 int cpu, struct pmu *pmu, struct list_head *events)
12988 {
12989 struct perf_event *event, *tmp;
12990
12991 /*
12992 * Re-instate events in 2 passes.
12993 *
12994 * Skip over group leaders and only install siblings on this first
12995 * pass, siblings will not get enabled without a leader, however a
12996 * leader will enable its siblings, even if those are still on the old
12997 * context.
12998 */
12999 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
13000 if (event->group_leader == event)
13001 continue;
13002
13003 list_del(&event->migrate_entry);
13004 __perf_pmu_install_event(pmu, ctx, cpu, event);
13005 }
13006
13007 /*
13008 * Once all the siblings are setup properly, install the group leaders
13009 * to make it go.
13010 */
13011 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
13012 list_del(&event->migrate_entry);
13013 __perf_pmu_install_event(pmu, ctx, cpu, event);
13014 }
13015 }
13016
perf_pmu_migrate_context(struct pmu * pmu,int src_cpu,int dst_cpu)13017 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
13018 {
13019 struct perf_event_context *src_ctx, *dst_ctx;
13020 LIST_HEAD(events);
13021
13022 /*
13023 * Since per-cpu context is persistent, no need to grab an extra
13024 * reference.
13025 */
13026 src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx;
13027 dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx;
13028
13029 /*
13030 * See perf_event_ctx_lock() for comments on the details
13031 * of swizzling perf_event::ctx.
13032 */
13033 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
13034
13035 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events);
13036 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events);
13037
13038 if (!list_empty(&events)) {
13039 /*
13040 * Wait for the events to quiesce before re-instating them.
13041 */
13042 synchronize_rcu();
13043
13044 __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events);
13045 }
13046
13047 mutex_unlock(&dst_ctx->mutex);
13048 mutex_unlock(&src_ctx->mutex);
13049 }
13050 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
13051
sync_child_event(struct perf_event * child_event)13052 static void sync_child_event(struct perf_event *child_event)
13053 {
13054 struct perf_event *parent_event = child_event->parent;
13055 u64 child_val;
13056
13057 if (child_event->attr.inherit_stat) {
13058 struct task_struct *task = child_event->ctx->task;
13059
13060 if (task && task != TASK_TOMBSTONE)
13061 perf_event_read_event(child_event, task);
13062 }
13063
13064 child_val = perf_event_count(child_event);
13065
13066 /*
13067 * Add back the child's count to the parent's count:
13068 */
13069 atomic64_add(child_val, &parent_event->child_count);
13070 atomic64_add(child_event->total_time_enabled,
13071 &parent_event->child_total_time_enabled);
13072 atomic64_add(child_event->total_time_running,
13073 &parent_event->child_total_time_running);
13074 }
13075
13076 static void
perf_event_exit_event(struct perf_event * event,struct perf_event_context * ctx)13077 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
13078 {
13079 struct perf_event *parent_event = event->parent;
13080 unsigned long detach_flags = 0;
13081
13082 if (parent_event) {
13083 /*
13084 * Do not destroy the 'original' grouping; because of the
13085 * context switch optimization the original events could've
13086 * ended up in a random child task.
13087 *
13088 * If we were to destroy the original group, all group related
13089 * operations would cease to function properly after this
13090 * random child dies.
13091 *
13092 * Do destroy all inherited groups, we don't care about those
13093 * and being thorough is better.
13094 */
13095 detach_flags = DETACH_GROUP | DETACH_CHILD;
13096 mutex_lock(&parent_event->child_mutex);
13097 }
13098
13099 perf_remove_from_context(event, detach_flags);
13100
13101 raw_spin_lock_irq(&ctx->lock);
13102 if (event->state > PERF_EVENT_STATE_EXIT)
13103 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
13104 raw_spin_unlock_irq(&ctx->lock);
13105
13106 /*
13107 * Child events can be freed.
13108 */
13109 if (parent_event) {
13110 mutex_unlock(&parent_event->child_mutex);
13111 /*
13112 * Kick perf_poll() for is_event_hup();
13113 */
13114 perf_event_wakeup(parent_event);
13115 free_event(event);
13116 put_event(parent_event);
13117 return;
13118 }
13119
13120 /*
13121 * Parent events are governed by their filedesc, retain them.
13122 */
13123 perf_event_wakeup(event);
13124 }
13125
perf_event_exit_task_context(struct task_struct * child)13126 static void perf_event_exit_task_context(struct task_struct *child)
13127 {
13128 struct perf_event_context *child_ctx, *clone_ctx = NULL;
13129 struct perf_event *child_event, *next;
13130
13131 WARN_ON_ONCE(child != current);
13132
13133 child_ctx = perf_pin_task_context(child);
13134 if (!child_ctx)
13135 return;
13136
13137 /*
13138 * In order to reduce the amount of tricky in ctx tear-down, we hold
13139 * ctx::mutex over the entire thing. This serializes against almost
13140 * everything that wants to access the ctx.
13141 *
13142 * The exception is sys_perf_event_open() /
13143 * perf_event_create_kernel_count() which does find_get_context()
13144 * without ctx::mutex (it cannot because of the move_group double mutex
13145 * lock thing). See the comments in perf_install_in_context().
13146 */
13147 mutex_lock(&child_ctx->mutex);
13148
13149 /*
13150 * In a single ctx::lock section, de-schedule the events and detach the
13151 * context from the task such that we cannot ever get it scheduled back
13152 * in.
13153 */
13154 raw_spin_lock_irq(&child_ctx->lock);
13155 task_ctx_sched_out(child_ctx, EVENT_ALL);
13156
13157 /*
13158 * Now that the context is inactive, destroy the task <-> ctx relation
13159 * and mark the context dead.
13160 */
13161 RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
13162 put_ctx(child_ctx); /* cannot be last */
13163 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
13164 put_task_struct(current); /* cannot be last */
13165
13166 clone_ctx = unclone_ctx(child_ctx);
13167 raw_spin_unlock_irq(&child_ctx->lock);
13168
13169 if (clone_ctx)
13170 put_ctx(clone_ctx);
13171
13172 /*
13173 * Report the task dead after unscheduling the events so that we
13174 * won't get any samples after PERF_RECORD_EXIT. We can however still
13175 * get a few PERF_RECORD_READ events.
13176 */
13177 perf_event_task(child, child_ctx, 0);
13178
13179 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
13180 perf_event_exit_event(child_event, child_ctx);
13181
13182 mutex_unlock(&child_ctx->mutex);
13183
13184 put_ctx(child_ctx);
13185 }
13186
13187 /*
13188 * When a child task exits, feed back event values to parent events.
13189 *
13190 * Can be called with exec_update_lock held when called from
13191 * setup_new_exec().
13192 */
perf_event_exit_task(struct task_struct * child)13193 void perf_event_exit_task(struct task_struct *child)
13194 {
13195 struct perf_event *event, *tmp;
13196
13197 mutex_lock(&child->perf_event_mutex);
13198 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
13199 owner_entry) {
13200 list_del_init(&event->owner_entry);
13201
13202 /*
13203 * Ensure the list deletion is visible before we clear
13204 * the owner, closes a race against perf_release() where
13205 * we need to serialize on the owner->perf_event_mutex.
13206 */
13207 smp_store_release(&event->owner, NULL);
13208 }
13209 mutex_unlock(&child->perf_event_mutex);
13210
13211 perf_event_exit_task_context(child);
13212
13213 /*
13214 * The perf_event_exit_task_context calls perf_event_task
13215 * with child's task_ctx, which generates EXIT events for
13216 * child contexts and sets child->perf_event_ctxp[] to NULL.
13217 * At this point we need to send EXIT events to cpu contexts.
13218 */
13219 perf_event_task(child, NULL, 0);
13220 }
13221
perf_free_event(struct perf_event * event,struct perf_event_context * ctx)13222 static void perf_free_event(struct perf_event *event,
13223 struct perf_event_context *ctx)
13224 {
13225 struct perf_event *parent = event->parent;
13226
13227 if (WARN_ON_ONCE(!parent))
13228 return;
13229
13230 mutex_lock(&parent->child_mutex);
13231 list_del_init(&event->child_list);
13232 mutex_unlock(&parent->child_mutex);
13233
13234 put_event(parent);
13235
13236 raw_spin_lock_irq(&ctx->lock);
13237 perf_group_detach(event);
13238 list_del_event(event, ctx);
13239 raw_spin_unlock_irq(&ctx->lock);
13240 free_event(event);
13241 }
13242
13243 /*
13244 * Free a context as created by inheritance by perf_event_init_task() below,
13245 * used by fork() in case of fail.
13246 *
13247 * Even though the task has never lived, the context and events have been
13248 * exposed through the child_list, so we must take care tearing it all down.
13249 */
perf_event_free_task(struct task_struct * task)13250 void perf_event_free_task(struct task_struct *task)
13251 {
13252 struct perf_event_context *ctx;
13253 struct perf_event *event, *tmp;
13254
13255 ctx = rcu_access_pointer(task->perf_event_ctxp);
13256 if (!ctx)
13257 return;
13258
13259 mutex_lock(&ctx->mutex);
13260 raw_spin_lock_irq(&ctx->lock);
13261 /*
13262 * Destroy the task <-> ctx relation and mark the context dead.
13263 *
13264 * This is important because even though the task hasn't been
13265 * exposed yet the context has been (through child_list).
13266 */
13267 RCU_INIT_POINTER(task->perf_event_ctxp, NULL);
13268 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
13269 put_task_struct(task); /* cannot be last */
13270 raw_spin_unlock_irq(&ctx->lock);
13271
13272
13273 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
13274 perf_free_event(event, ctx);
13275
13276 mutex_unlock(&ctx->mutex);
13277
13278 /*
13279 * perf_event_release_kernel() could've stolen some of our
13280 * child events and still have them on its free_list. In that
13281 * case we must wait for these events to have been freed (in
13282 * particular all their references to this task must've been
13283 * dropped).
13284 *
13285 * Without this copy_process() will unconditionally free this
13286 * task (irrespective of its reference count) and
13287 * _free_event()'s put_task_struct(event->hw.target) will be a
13288 * use-after-free.
13289 *
13290 * Wait for all events to drop their context reference.
13291 */
13292 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
13293 put_ctx(ctx); /* must be last */
13294 }
13295
perf_event_delayed_put(struct task_struct * task)13296 void perf_event_delayed_put(struct task_struct *task)
13297 {
13298 WARN_ON_ONCE(task->perf_event_ctxp);
13299 }
13300
perf_event_get(unsigned int fd)13301 struct file *perf_event_get(unsigned int fd)
13302 {
13303 struct file *file = fget(fd);
13304 if (!file)
13305 return ERR_PTR(-EBADF);
13306
13307 if (file->f_op != &perf_fops) {
13308 fput(file);
13309 return ERR_PTR(-EBADF);
13310 }
13311
13312 return file;
13313 }
13314
perf_get_event(struct file * file)13315 const struct perf_event *perf_get_event(struct file *file)
13316 {
13317 if (file->f_op != &perf_fops)
13318 return ERR_PTR(-EINVAL);
13319
13320 return file->private_data;
13321 }
13322
perf_event_attrs(struct perf_event * event)13323 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13324 {
13325 if (!event)
13326 return ERR_PTR(-EINVAL);
13327
13328 return &event->attr;
13329 }
13330
13331 /*
13332 * Inherit an event from parent task to child task.
13333 *
13334 * Returns:
13335 * - valid pointer on success
13336 * - NULL for orphaned events
13337 * - IS_ERR() on error
13338 */
13339 static struct perf_event *
inherit_event(struct perf_event * parent_event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,struct perf_event * group_leader,struct perf_event_context * child_ctx)13340 inherit_event(struct perf_event *parent_event,
13341 struct task_struct *parent,
13342 struct perf_event_context *parent_ctx,
13343 struct task_struct *child,
13344 struct perf_event *group_leader,
13345 struct perf_event_context *child_ctx)
13346 {
13347 enum perf_event_state parent_state = parent_event->state;
13348 struct perf_event_pmu_context *pmu_ctx;
13349 struct perf_event *child_event;
13350 unsigned long flags;
13351
13352 /*
13353 * Instead of creating recursive hierarchies of events,
13354 * we link inherited events back to the original parent,
13355 * which has a filp for sure, which we use as the reference
13356 * count:
13357 */
13358 if (parent_event->parent)
13359 parent_event = parent_event->parent;
13360
13361 child_event = perf_event_alloc(&parent_event->attr,
13362 parent_event->cpu,
13363 child,
13364 group_leader, parent_event,
13365 NULL, NULL, -1);
13366 if (IS_ERR(child_event))
13367 return child_event;
13368
13369 pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
13370 if (IS_ERR(pmu_ctx)) {
13371 free_event(child_event);
13372 return ERR_CAST(pmu_ctx);
13373 }
13374 child_event->pmu_ctx = pmu_ctx;
13375
13376 /*
13377 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13378 * must be under the same lock in order to serialize against
13379 * perf_event_release_kernel(), such that either we must observe
13380 * is_orphaned_event() or they will observe us on the child_list.
13381 */
13382 mutex_lock(&parent_event->child_mutex);
13383 if (is_orphaned_event(parent_event) ||
13384 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13385 mutex_unlock(&parent_event->child_mutex);
13386 /* task_ctx_data is freed with child_ctx */
13387 free_event(child_event);
13388 return NULL;
13389 }
13390
13391 get_ctx(child_ctx);
13392
13393 /*
13394 * Make the child state follow the state of the parent event,
13395 * not its attr.disabled bit. We hold the parent's mutex,
13396 * so we won't race with perf_event_{en, dis}able_family.
13397 */
13398 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13399 child_event->state = PERF_EVENT_STATE_INACTIVE;
13400 else
13401 child_event->state = PERF_EVENT_STATE_OFF;
13402
13403 if (parent_event->attr.freq) {
13404 u64 sample_period = parent_event->hw.sample_period;
13405 struct hw_perf_event *hwc = &child_event->hw;
13406
13407 hwc->sample_period = sample_period;
13408 hwc->last_period = sample_period;
13409
13410 local64_set(&hwc->period_left, sample_period);
13411 }
13412
13413 child_event->ctx = child_ctx;
13414 child_event->overflow_handler = parent_event->overflow_handler;
13415 child_event->overflow_handler_context
13416 = parent_event->overflow_handler_context;
13417
13418 /*
13419 * Precalculate sample_data sizes
13420 */
13421 perf_event__header_size(child_event);
13422 perf_event__id_header_size(child_event);
13423
13424 /*
13425 * Link it up in the child's context:
13426 */
13427 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13428 add_event_to_ctx(child_event, child_ctx);
13429 child_event->attach_state |= PERF_ATTACH_CHILD;
13430 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13431
13432 /*
13433 * Link this into the parent event's child list
13434 */
13435 list_add_tail(&child_event->child_list, &parent_event->child_list);
13436 mutex_unlock(&parent_event->child_mutex);
13437
13438 return child_event;
13439 }
13440
13441 /*
13442 * Inherits an event group.
13443 *
13444 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13445 * This matches with perf_event_release_kernel() removing all child events.
13446 *
13447 * Returns:
13448 * - 0 on success
13449 * - <0 on error
13450 */
inherit_group(struct perf_event * parent_event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,struct perf_event_context * child_ctx)13451 static int inherit_group(struct perf_event *parent_event,
13452 struct task_struct *parent,
13453 struct perf_event_context *parent_ctx,
13454 struct task_struct *child,
13455 struct perf_event_context *child_ctx)
13456 {
13457 struct perf_event *leader;
13458 struct perf_event *sub;
13459 struct perf_event *child_ctr;
13460
13461 leader = inherit_event(parent_event, parent, parent_ctx,
13462 child, NULL, child_ctx);
13463 if (IS_ERR(leader))
13464 return PTR_ERR(leader);
13465 /*
13466 * @leader can be NULL here because of is_orphaned_event(). In this
13467 * case inherit_event() will create individual events, similar to what
13468 * perf_group_detach() would do anyway.
13469 */
13470 for_each_sibling_event(sub, parent_event) {
13471 child_ctr = inherit_event(sub, parent, parent_ctx,
13472 child, leader, child_ctx);
13473 if (IS_ERR(child_ctr))
13474 return PTR_ERR(child_ctr);
13475
13476 if (sub->aux_event == parent_event && child_ctr &&
13477 !perf_get_aux_event(child_ctr, leader))
13478 return -EINVAL;
13479 }
13480 if (leader)
13481 leader->group_generation = parent_event->group_generation;
13482 return 0;
13483 }
13484
13485 /*
13486 * Creates the child task context and tries to inherit the event-group.
13487 *
13488 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13489 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13490 * consistent with perf_event_release_kernel() removing all child events.
13491 *
13492 * Returns:
13493 * - 0 on success
13494 * - <0 on error
13495 */
13496 static int
inherit_task_group(struct perf_event * event,struct task_struct * parent,struct perf_event_context * parent_ctx,struct task_struct * child,u64 clone_flags,int * inherited_all)13497 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13498 struct perf_event_context *parent_ctx,
13499 struct task_struct *child,
13500 u64 clone_flags, int *inherited_all)
13501 {
13502 struct perf_event_context *child_ctx;
13503 int ret;
13504
13505 if (!event->attr.inherit ||
13506 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13507 /* Do not inherit if sigtrap and signal handlers were cleared. */
13508 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13509 *inherited_all = 0;
13510 return 0;
13511 }
13512
13513 child_ctx = child->perf_event_ctxp;
13514 if (!child_ctx) {
13515 /*
13516 * This is executed from the parent task context, so
13517 * inherit events that have been marked for cloning.
13518 * First allocate and initialize a context for the
13519 * child.
13520 */
13521 child_ctx = alloc_perf_context(child);
13522 if (!child_ctx)
13523 return -ENOMEM;
13524
13525 child->perf_event_ctxp = child_ctx;
13526 }
13527
13528 ret = inherit_group(event, parent, parent_ctx, child, child_ctx);
13529 if (ret)
13530 *inherited_all = 0;
13531
13532 return ret;
13533 }
13534
13535 /*
13536 * Initialize the perf_event context in task_struct
13537 */
perf_event_init_context(struct task_struct * child,u64 clone_flags)13538 static int perf_event_init_context(struct task_struct *child, u64 clone_flags)
13539 {
13540 struct perf_event_context *child_ctx, *parent_ctx;
13541 struct perf_event_context *cloned_ctx;
13542 struct perf_event *event;
13543 struct task_struct *parent = current;
13544 int inherited_all = 1;
13545 unsigned long flags;
13546 int ret = 0;
13547
13548 if (likely(!parent->perf_event_ctxp))
13549 return 0;
13550
13551 /*
13552 * If the parent's context is a clone, pin it so it won't get
13553 * swapped under us.
13554 */
13555 parent_ctx = perf_pin_task_context(parent);
13556 if (!parent_ctx)
13557 return 0;
13558
13559 /*
13560 * No need to check if parent_ctx != NULL here; since we saw
13561 * it non-NULL earlier, the only reason for it to become NULL
13562 * is if we exit, and since we're currently in the middle of
13563 * a fork we can't be exiting at the same time.
13564 */
13565
13566 /*
13567 * Lock the parent list. No need to lock the child - not PID
13568 * hashed yet and not running, so nobody can access it.
13569 */
13570 mutex_lock(&parent_ctx->mutex);
13571
13572 /*
13573 * We dont have to disable NMIs - we are only looking at
13574 * the list, not manipulating it:
13575 */
13576 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13577 ret = inherit_task_group(event, parent, parent_ctx,
13578 child, clone_flags, &inherited_all);
13579 if (ret)
13580 goto out_unlock;
13581 }
13582
13583 /*
13584 * We can't hold ctx->lock when iterating the ->flexible_group list due
13585 * to allocations, but we need to prevent rotation because
13586 * rotate_ctx() will change the list from interrupt context.
13587 */
13588 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13589 parent_ctx->rotate_disable = 1;
13590 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13591
13592 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13593 ret = inherit_task_group(event, parent, parent_ctx,
13594 child, clone_flags, &inherited_all);
13595 if (ret)
13596 goto out_unlock;
13597 }
13598
13599 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13600 parent_ctx->rotate_disable = 0;
13601
13602 child_ctx = child->perf_event_ctxp;
13603
13604 if (child_ctx && inherited_all) {
13605 /*
13606 * Mark the child context as a clone of the parent
13607 * context, or of whatever the parent is a clone of.
13608 *
13609 * Note that if the parent is a clone, the holding of
13610 * parent_ctx->lock avoids it from being uncloned.
13611 */
13612 cloned_ctx = parent_ctx->parent_ctx;
13613 if (cloned_ctx) {
13614 child_ctx->parent_ctx = cloned_ctx;
13615 child_ctx->parent_gen = parent_ctx->parent_gen;
13616 } else {
13617 child_ctx->parent_ctx = parent_ctx;
13618 child_ctx->parent_gen = parent_ctx->generation;
13619 }
13620 get_ctx(child_ctx->parent_ctx);
13621 }
13622
13623 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13624 out_unlock:
13625 mutex_unlock(&parent_ctx->mutex);
13626
13627 perf_unpin_context(parent_ctx);
13628 put_ctx(parent_ctx);
13629
13630 return ret;
13631 }
13632
13633 /*
13634 * Initialize the perf_event context in task_struct
13635 */
perf_event_init_task(struct task_struct * child,u64 clone_flags)13636 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13637 {
13638 int ret;
13639
13640 child->perf_event_ctxp = NULL;
13641 mutex_init(&child->perf_event_mutex);
13642 INIT_LIST_HEAD(&child->perf_event_list);
13643
13644 ret = perf_event_init_context(child, clone_flags);
13645 if (ret) {
13646 perf_event_free_task(child);
13647 return ret;
13648 }
13649
13650 return 0;
13651 }
13652
perf_event_init_all_cpus(void)13653 static void __init perf_event_init_all_cpus(void)
13654 {
13655 struct swevent_htable *swhash;
13656 struct perf_cpu_context *cpuctx;
13657 int cpu;
13658
13659 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13660
13661 for_each_possible_cpu(cpu) {
13662 swhash = &per_cpu(swevent_htable, cpu);
13663 mutex_init(&swhash->hlist_mutex);
13664
13665 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13666 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13667
13668 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13669
13670 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13671 __perf_event_init_context(&cpuctx->ctx);
13672 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
13673 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
13674 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
13675 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
13676 cpuctx->heap = cpuctx->heap_default;
13677 }
13678 }
13679
perf_swevent_init_cpu(unsigned int cpu)13680 static void perf_swevent_init_cpu(unsigned int cpu)
13681 {
13682 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13683
13684 mutex_lock(&swhash->hlist_mutex);
13685 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13686 struct swevent_hlist *hlist;
13687
13688 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13689 WARN_ON(!hlist);
13690 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13691 }
13692 mutex_unlock(&swhash->hlist_mutex);
13693 }
13694
13695 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
__perf_event_exit_context(void * __info)13696 static void __perf_event_exit_context(void *__info)
13697 {
13698 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
13699 struct perf_event_context *ctx = __info;
13700 struct perf_event *event;
13701
13702 raw_spin_lock(&ctx->lock);
13703 ctx_sched_out(ctx, EVENT_TIME);
13704 list_for_each_entry(event, &ctx->event_list, event_entry)
13705 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13706 raw_spin_unlock(&ctx->lock);
13707 }
13708
perf_event_exit_cpu_context(int cpu)13709 static void perf_event_exit_cpu_context(int cpu)
13710 {
13711 struct perf_cpu_context *cpuctx;
13712 struct perf_event_context *ctx;
13713
13714 // XXX simplify cpuctx->online
13715 mutex_lock(&pmus_lock);
13716 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13717 ctx = &cpuctx->ctx;
13718
13719 mutex_lock(&ctx->mutex);
13720 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13721 cpuctx->online = 0;
13722 mutex_unlock(&ctx->mutex);
13723 cpumask_clear_cpu(cpu, perf_online_mask);
13724 mutex_unlock(&pmus_lock);
13725 }
13726 #else
13727
perf_event_exit_cpu_context(int cpu)13728 static void perf_event_exit_cpu_context(int cpu) { }
13729
13730 #endif
13731
perf_event_init_cpu(unsigned int cpu)13732 int perf_event_init_cpu(unsigned int cpu)
13733 {
13734 struct perf_cpu_context *cpuctx;
13735 struct perf_event_context *ctx;
13736
13737 perf_swevent_init_cpu(cpu);
13738
13739 mutex_lock(&pmus_lock);
13740 cpumask_set_cpu(cpu, perf_online_mask);
13741 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13742 ctx = &cpuctx->ctx;
13743
13744 mutex_lock(&ctx->mutex);
13745 cpuctx->online = 1;
13746 mutex_unlock(&ctx->mutex);
13747 mutex_unlock(&pmus_lock);
13748
13749 return 0;
13750 }
13751
perf_event_exit_cpu(unsigned int cpu)13752 int perf_event_exit_cpu(unsigned int cpu)
13753 {
13754 perf_event_exit_cpu_context(cpu);
13755 return 0;
13756 }
13757
13758 static int
perf_reboot(struct notifier_block * notifier,unsigned long val,void * v)13759 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13760 {
13761 int cpu;
13762
13763 for_each_online_cpu(cpu)
13764 perf_event_exit_cpu(cpu);
13765
13766 return NOTIFY_OK;
13767 }
13768
13769 /*
13770 * Run the perf reboot notifier at the very last possible moment so that
13771 * the generic watchdog code runs as long as possible.
13772 */
13773 static struct notifier_block perf_reboot_notifier = {
13774 .notifier_call = perf_reboot,
13775 .priority = INT_MIN,
13776 };
13777
perf_event_init(void)13778 void __init perf_event_init(void)
13779 {
13780 int ret;
13781
13782 idr_init(&pmu_idr);
13783
13784 perf_event_init_all_cpus();
13785 init_srcu_struct(&pmus_srcu);
13786 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13787 perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1);
13788 perf_pmu_register(&perf_task_clock, "task_clock", -1);
13789 perf_tp_register();
13790 perf_event_init_cpu(smp_processor_id());
13791 register_reboot_notifier(&perf_reboot_notifier);
13792
13793 ret = init_hw_breakpoint();
13794 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13795
13796 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13797
13798 /*
13799 * Build time assertion that we keep the data_head at the intended
13800 * location. IOW, validation we got the __reserved[] size right.
13801 */
13802 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13803 != 1024);
13804 }
13805
perf_event_sysfs_show(struct device * dev,struct device_attribute * attr,char * page)13806 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13807 char *page)
13808 {
13809 struct perf_pmu_events_attr *pmu_attr =
13810 container_of(attr, struct perf_pmu_events_attr, attr);
13811
13812 if (pmu_attr->event_str)
13813 return sprintf(page, "%s\n", pmu_attr->event_str);
13814
13815 return 0;
13816 }
13817 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13818
perf_event_sysfs_init(void)13819 static int __init perf_event_sysfs_init(void)
13820 {
13821 struct pmu *pmu;
13822 int ret;
13823
13824 mutex_lock(&pmus_lock);
13825
13826 ret = bus_register(&pmu_bus);
13827 if (ret)
13828 goto unlock;
13829
13830 list_for_each_entry(pmu, &pmus, entry) {
13831 if (pmu->dev)
13832 continue;
13833
13834 ret = pmu_dev_alloc(pmu);
13835 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13836 }
13837 pmu_bus_running = 1;
13838 ret = 0;
13839
13840 unlock:
13841 mutex_unlock(&pmus_lock);
13842
13843 return ret;
13844 }
13845 device_initcall(perf_event_sysfs_init);
13846
13847 #ifdef CONFIG_CGROUP_PERF
13848 static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state * parent_css)13849 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13850 {
13851 struct perf_cgroup *jc;
13852
13853 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13854 if (!jc)
13855 return ERR_PTR(-ENOMEM);
13856
13857 jc->info = alloc_percpu(struct perf_cgroup_info);
13858 if (!jc->info) {
13859 kfree(jc);
13860 return ERR_PTR(-ENOMEM);
13861 }
13862
13863 return &jc->css;
13864 }
13865
perf_cgroup_css_free(struct cgroup_subsys_state * css)13866 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13867 {
13868 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13869
13870 free_percpu(jc->info);
13871 kfree(jc);
13872 }
13873
perf_cgroup_css_online(struct cgroup_subsys_state * css)13874 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13875 {
13876 perf_event_cgroup(css->cgroup);
13877 return 0;
13878 }
13879
__perf_cgroup_move(void * info)13880 static int __perf_cgroup_move(void *info)
13881 {
13882 struct task_struct *task = info;
13883
13884 preempt_disable();
13885 perf_cgroup_switch(task);
13886 preempt_enable();
13887
13888 return 0;
13889 }
13890
perf_cgroup_attach(struct cgroup_taskset * tset)13891 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13892 {
13893 struct task_struct *task;
13894 struct cgroup_subsys_state *css;
13895
13896 cgroup_taskset_for_each(task, css, tset)
13897 task_function_call(task, __perf_cgroup_move, task);
13898 }
13899
13900 struct cgroup_subsys perf_event_cgrp_subsys = {
13901 .css_alloc = perf_cgroup_css_alloc,
13902 .css_free = perf_cgroup_css_free,
13903 .css_online = perf_cgroup_css_online,
13904 .attach = perf_cgroup_attach,
13905 /*
13906 * Implicitly enable on dfl hierarchy so that perf events can
13907 * always be filtered by cgroup2 path as long as perf_event
13908 * controller is not mounted on a legacy hierarchy.
13909 */
13910 .implicit_on_dfl = true,
13911 .threaded = true,
13912 };
13913 #endif /* CONFIG_CGROUP_PERF */
13914
13915 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
13916