1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Based on code from the latency_tracer, that is:
9 *
10 * Copyright (C) 2004-2006 Ingo Molnar
11 * Copyright (C) 2004 Nadia Yvette Chambers
12 */
13 #include <linux/ring_buffer.h>
14 #include <linux/debugfs.h>
15 #include <linux/uaccess.h>
16 #include <linux/ftrace.h>
17 #include <linux/slab.h>
18 #include <linux/fs.h>
19
20 #include "trace.h"
21
22 static void tracing_start_function_trace(struct trace_array *tr);
23 static void tracing_stop_function_trace(struct trace_array *tr);
24 static void
25 function_trace_call(unsigned long ip, unsigned long parent_ip,
26 struct ftrace_ops *op, struct ftrace_regs *fregs);
27 static void
28 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
29 struct ftrace_ops *op, struct ftrace_regs *fregs);
30 static void
31 function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
32 struct ftrace_ops *op, struct ftrace_regs *fregs);
33 static void
34 function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
35 struct ftrace_ops *op,
36 struct ftrace_regs *fregs);
37 static struct tracer_flags func_flags;
38
39 /* Our option */
40 enum {
41
42 TRACE_FUNC_NO_OPTS = 0x0, /* No flags set. */
43 TRACE_FUNC_OPT_STACK = 0x1,
44 TRACE_FUNC_OPT_NO_REPEATS = 0x2,
45
46 /* Update this to next highest bit. */
47 TRACE_FUNC_OPT_HIGHEST_BIT = 0x4
48 };
49
50 #define TRACE_FUNC_OPT_MASK (TRACE_FUNC_OPT_HIGHEST_BIT - 1)
51
ftrace_allocate_ftrace_ops(struct trace_array * tr)52 int ftrace_allocate_ftrace_ops(struct trace_array *tr)
53 {
54 struct ftrace_ops *ops;
55
56 /* The top level array uses the "global_ops" */
57 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
58 return 0;
59
60 ops = kzalloc(sizeof(*ops), GFP_KERNEL);
61 if (!ops)
62 return -ENOMEM;
63
64 /* Currently only the non stack version is supported */
65 ops->func = function_trace_call;
66 ops->flags = FTRACE_OPS_FL_PID;
67
68 tr->ops = ops;
69 ops->private = tr;
70
71 return 0;
72 }
73
ftrace_free_ftrace_ops(struct trace_array * tr)74 void ftrace_free_ftrace_ops(struct trace_array *tr)
75 {
76 kfree(tr->ops);
77 tr->ops = NULL;
78 }
79
ftrace_create_function_files(struct trace_array * tr,struct dentry * parent)80 int ftrace_create_function_files(struct trace_array *tr,
81 struct dentry *parent)
82 {
83 /*
84 * The top level array uses the "global_ops", and the files are
85 * created on boot up.
86 */
87 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
88 return 0;
89
90 if (!tr->ops)
91 return -EINVAL;
92
93 ftrace_create_filter_files(tr->ops, parent);
94
95 return 0;
96 }
97
ftrace_destroy_function_files(struct trace_array * tr)98 void ftrace_destroy_function_files(struct trace_array *tr)
99 {
100 ftrace_destroy_filter_files(tr->ops);
101 ftrace_free_ftrace_ops(tr);
102 }
103
select_trace_function(u32 flags_val)104 static ftrace_func_t select_trace_function(u32 flags_val)
105 {
106 switch (flags_val & TRACE_FUNC_OPT_MASK) {
107 case TRACE_FUNC_NO_OPTS:
108 return function_trace_call;
109 case TRACE_FUNC_OPT_STACK:
110 return function_stack_trace_call;
111 case TRACE_FUNC_OPT_NO_REPEATS:
112 return function_no_repeats_trace_call;
113 case TRACE_FUNC_OPT_STACK | TRACE_FUNC_OPT_NO_REPEATS:
114 return function_stack_no_repeats_trace_call;
115 default:
116 return NULL;
117 }
118 }
119
handle_func_repeats(struct trace_array * tr,u32 flags_val)120 static bool handle_func_repeats(struct trace_array *tr, u32 flags_val)
121 {
122 if (!tr->last_func_repeats &&
123 (flags_val & TRACE_FUNC_OPT_NO_REPEATS)) {
124 tr->last_func_repeats = alloc_percpu(struct trace_func_repeats);
125 if (!tr->last_func_repeats)
126 return false;
127 }
128
129 return true;
130 }
131
function_trace_init(struct trace_array * tr)132 static int function_trace_init(struct trace_array *tr)
133 {
134 ftrace_func_t func;
135 /*
136 * Instance trace_arrays get their ops allocated
137 * at instance creation. Unless it failed
138 * the allocation.
139 */
140 if (!tr->ops)
141 return -ENOMEM;
142
143 func = select_trace_function(func_flags.val);
144 if (!func)
145 return -EINVAL;
146
147 if (!handle_func_repeats(tr, func_flags.val))
148 return -ENOMEM;
149
150 ftrace_init_array_ops(tr, func);
151
152 tr->array_buffer.cpu = raw_smp_processor_id();
153
154 tracing_start_cmdline_record();
155 tracing_start_function_trace(tr);
156 return 0;
157 }
158
function_trace_reset(struct trace_array * tr)159 static void function_trace_reset(struct trace_array *tr)
160 {
161 tracing_stop_function_trace(tr);
162 tracing_stop_cmdline_record();
163 ftrace_reset_array_ops(tr);
164 }
165
function_trace_start(struct trace_array * tr)166 static void function_trace_start(struct trace_array *tr)
167 {
168 tracing_reset_online_cpus(&tr->array_buffer);
169 }
170
171 static void
function_trace_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)172 function_trace_call(unsigned long ip, unsigned long parent_ip,
173 struct ftrace_ops *op, struct ftrace_regs *fregs)
174 {
175 struct trace_array *tr = op->private;
176 struct trace_array_cpu *data;
177 unsigned int trace_ctx;
178 int bit;
179 int cpu;
180
181 if (unlikely(!tr->function_enabled))
182 return;
183
184 bit = ftrace_test_recursion_trylock(ip, parent_ip);
185 if (bit < 0)
186 return;
187
188 trace_ctx = tracing_gen_ctx();
189 preempt_disable_notrace();
190
191 cpu = smp_processor_id();
192 data = per_cpu_ptr(tr->array_buffer.data, cpu);
193 if (!atomic_read(&data->disabled))
194 trace_function(tr, ip, parent_ip, trace_ctx);
195
196 ftrace_test_recursion_unlock(bit);
197 preempt_enable_notrace();
198 }
199
200 #ifdef CONFIG_UNWINDER_ORC
201 /*
202 * Skip 2:
203 *
204 * function_stack_trace_call()
205 * ftrace_call()
206 */
207 #define STACK_SKIP 2
208 #else
209 /*
210 * Skip 3:
211 * __trace_stack()
212 * function_stack_trace_call()
213 * ftrace_call()
214 */
215 #define STACK_SKIP 3
216 #endif
217
218 static void
function_stack_trace_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)219 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
220 struct ftrace_ops *op, struct ftrace_regs *fregs)
221 {
222 struct trace_array *tr = op->private;
223 struct trace_array_cpu *data;
224 unsigned long flags;
225 long disabled;
226 int cpu;
227 unsigned int trace_ctx;
228
229 if (unlikely(!tr->function_enabled))
230 return;
231
232 /*
233 * Need to use raw, since this must be called before the
234 * recursive protection is performed.
235 */
236 local_irq_save(flags);
237 cpu = raw_smp_processor_id();
238 data = per_cpu_ptr(tr->array_buffer.data, cpu);
239 disabled = atomic_inc_return(&data->disabled);
240
241 if (likely(disabled == 1)) {
242 trace_ctx = tracing_gen_ctx_flags(flags);
243 trace_function(tr, ip, parent_ip, trace_ctx);
244 __trace_stack(tr, trace_ctx, STACK_SKIP);
245 }
246
247 atomic_dec(&data->disabled);
248 local_irq_restore(flags);
249 }
250
is_repeat_check(struct trace_array * tr,struct trace_func_repeats * last_info,unsigned long ip,unsigned long parent_ip)251 static inline bool is_repeat_check(struct trace_array *tr,
252 struct trace_func_repeats *last_info,
253 unsigned long ip, unsigned long parent_ip)
254 {
255 if (last_info->ip == ip &&
256 last_info->parent_ip == parent_ip &&
257 last_info->count < U16_MAX) {
258 last_info->ts_last_call =
259 ring_buffer_time_stamp(tr->array_buffer.buffer);
260 last_info->count++;
261 return true;
262 }
263
264 return false;
265 }
266
process_repeats(struct trace_array * tr,unsigned long ip,unsigned long parent_ip,struct trace_func_repeats * last_info,unsigned int trace_ctx)267 static inline void process_repeats(struct trace_array *tr,
268 unsigned long ip, unsigned long parent_ip,
269 struct trace_func_repeats *last_info,
270 unsigned int trace_ctx)
271 {
272 if (last_info->count) {
273 trace_last_func_repeats(tr, last_info, trace_ctx);
274 last_info->count = 0;
275 }
276
277 last_info->ip = ip;
278 last_info->parent_ip = parent_ip;
279 }
280
281 static void
function_no_repeats_trace_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)282 function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
283 struct ftrace_ops *op,
284 struct ftrace_regs *fregs)
285 {
286 struct trace_func_repeats *last_info;
287 struct trace_array *tr = op->private;
288 struct trace_array_cpu *data;
289 unsigned int trace_ctx;
290 unsigned long flags;
291 int bit;
292 int cpu;
293
294 if (unlikely(!tr->function_enabled))
295 return;
296
297 bit = ftrace_test_recursion_trylock(ip, parent_ip);
298 if (bit < 0)
299 return;
300
301 preempt_disable_notrace();
302
303 cpu = smp_processor_id();
304 data = per_cpu_ptr(tr->array_buffer.data, cpu);
305 if (atomic_read(&data->disabled))
306 goto out;
307
308 /*
309 * An interrupt may happen at any place here. But as far as I can see,
310 * the only damage that this can cause is to mess up the repetition
311 * counter without valuable data being lost.
312 * TODO: think about a solution that is better than just hoping to be
313 * lucky.
314 */
315 last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
316 if (is_repeat_check(tr, last_info, ip, parent_ip))
317 goto out;
318
319 local_save_flags(flags);
320 trace_ctx = tracing_gen_ctx_flags(flags);
321 process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
322
323 trace_function(tr, ip, parent_ip, trace_ctx);
324
325 out:
326 ftrace_test_recursion_unlock(bit);
327 preempt_enable_notrace();
328 }
329
330 static void
function_stack_no_repeats_trace_call(unsigned long ip,unsigned long parent_ip,struct ftrace_ops * op,struct ftrace_regs * fregs)331 function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
332 struct ftrace_ops *op,
333 struct ftrace_regs *fregs)
334 {
335 struct trace_func_repeats *last_info;
336 struct trace_array *tr = op->private;
337 struct trace_array_cpu *data;
338 unsigned long flags;
339 long disabled;
340 int cpu;
341 unsigned int trace_ctx;
342
343 if (unlikely(!tr->function_enabled))
344 return;
345
346 /*
347 * Need to use raw, since this must be called before the
348 * recursive protection is performed.
349 */
350 local_irq_save(flags);
351 cpu = raw_smp_processor_id();
352 data = per_cpu_ptr(tr->array_buffer.data, cpu);
353 disabled = atomic_inc_return(&data->disabled);
354
355 if (likely(disabled == 1)) {
356 last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
357 if (is_repeat_check(tr, last_info, ip, parent_ip))
358 goto out;
359
360 trace_ctx = tracing_gen_ctx_flags(flags);
361 process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
362
363 trace_function(tr, ip, parent_ip, trace_ctx);
364 __trace_stack(tr, trace_ctx, STACK_SKIP);
365 }
366
367 out:
368 atomic_dec(&data->disabled);
369 local_irq_restore(flags);
370 }
371
372 static struct tracer_opt func_opts[] = {
373 #ifdef CONFIG_STACKTRACE
374 { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
375 #endif
376 { TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
377 { } /* Always set a last empty entry */
378 };
379
380 static struct tracer_flags func_flags = {
381 .val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */
382 .opts = func_opts
383 };
384
tracing_start_function_trace(struct trace_array * tr)385 static void tracing_start_function_trace(struct trace_array *tr)
386 {
387 tr->function_enabled = 0;
388 register_ftrace_function(tr->ops);
389 tr->function_enabled = 1;
390 }
391
tracing_stop_function_trace(struct trace_array * tr)392 static void tracing_stop_function_trace(struct trace_array *tr)
393 {
394 tr->function_enabled = 0;
395 unregister_ftrace_function(tr->ops);
396 }
397
398 static struct tracer function_trace;
399
400 static int
func_set_flag(struct trace_array * tr,u32 old_flags,u32 bit,int set)401 func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
402 {
403 ftrace_func_t func;
404 u32 new_flags;
405
406 /* Do nothing if already set. */
407 if (!!set == !!(func_flags.val & bit))
408 return 0;
409
410 /* We can change this flag only when not running. */
411 if (tr->current_trace != &function_trace)
412 return 0;
413
414 new_flags = (func_flags.val & ~bit) | (set ? bit : 0);
415 func = select_trace_function(new_flags);
416 if (!func)
417 return -EINVAL;
418
419 /* Check if there's anything to change. */
420 if (tr->ops->func == func)
421 return 0;
422
423 if (!handle_func_repeats(tr, new_flags))
424 return -ENOMEM;
425
426 unregister_ftrace_function(tr->ops);
427 tr->ops->func = func;
428 register_ftrace_function(tr->ops);
429
430 return 0;
431 }
432
433 static struct tracer function_trace __tracer_data =
434 {
435 .name = "function",
436 .init = function_trace_init,
437 .reset = function_trace_reset,
438 .start = function_trace_start,
439 .flags = &func_flags,
440 .set_flag = func_set_flag,
441 .allow_instances = true,
442 #ifdef CONFIG_FTRACE_SELFTEST
443 .selftest = trace_selftest_startup_function,
444 #endif
445 };
446
447 #ifdef CONFIG_DYNAMIC_FTRACE
update_traceon_count(struct ftrace_probe_ops * ops,unsigned long ip,struct trace_array * tr,bool on,void * data)448 static void update_traceon_count(struct ftrace_probe_ops *ops,
449 unsigned long ip,
450 struct trace_array *tr, bool on,
451 void *data)
452 {
453 struct ftrace_func_mapper *mapper = data;
454 long *count;
455 long old_count;
456
457 /*
458 * Tracing gets disabled (or enabled) once per count.
459 * This function can be called at the same time on multiple CPUs.
460 * It is fine if both disable (or enable) tracing, as disabling
461 * (or enabling) the second time doesn't do anything as the
462 * state of the tracer is already disabled (or enabled).
463 * What needs to be synchronized in this case is that the count
464 * only gets decremented once, even if the tracer is disabled
465 * (or enabled) twice, as the second one is really a nop.
466 *
467 * The memory barriers guarantee that we only decrement the
468 * counter once. First the count is read to a local variable
469 * and a read barrier is used to make sure that it is loaded
470 * before checking if the tracer is in the state we want.
471 * If the tracer is not in the state we want, then the count
472 * is guaranteed to be the old count.
473 *
474 * Next the tracer is set to the state we want (disabled or enabled)
475 * then a write memory barrier is used to make sure that
476 * the new state is visible before changing the counter by
477 * one minus the old counter. This guarantees that another CPU
478 * executing this code will see the new state before seeing
479 * the new counter value, and would not do anything if the new
480 * counter is seen.
481 *
482 * Note, there is no synchronization between this and a user
483 * setting the tracing_on file. But we currently don't care
484 * about that.
485 */
486 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
487 old_count = *count;
488
489 if (old_count <= 0)
490 return;
491
492 /* Make sure we see count before checking tracing state */
493 smp_rmb();
494
495 if (on == !!tracer_tracing_is_on(tr))
496 return;
497
498 if (on)
499 tracer_tracing_on(tr);
500 else
501 tracer_tracing_off(tr);
502
503 /* Make sure tracing state is visible before updating count */
504 smp_wmb();
505
506 *count = old_count - 1;
507 }
508
509 static void
ftrace_traceon_count(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)510 ftrace_traceon_count(unsigned long ip, unsigned long parent_ip,
511 struct trace_array *tr, struct ftrace_probe_ops *ops,
512 void *data)
513 {
514 update_traceon_count(ops, ip, tr, 1, data);
515 }
516
517 static void
ftrace_traceoff_count(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)518 ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip,
519 struct trace_array *tr, struct ftrace_probe_ops *ops,
520 void *data)
521 {
522 update_traceon_count(ops, ip, tr, 0, data);
523 }
524
525 static void
ftrace_traceon(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)526 ftrace_traceon(unsigned long ip, unsigned long parent_ip,
527 struct trace_array *tr, struct ftrace_probe_ops *ops,
528 void *data)
529 {
530 if (tracer_tracing_is_on(tr))
531 return;
532
533 tracer_tracing_on(tr);
534 }
535
536 static void
ftrace_traceoff(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)537 ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
538 struct trace_array *tr, struct ftrace_probe_ops *ops,
539 void *data)
540 {
541 if (!tracer_tracing_is_on(tr))
542 return;
543
544 tracer_tracing_off(tr);
545 }
546
547 #ifdef CONFIG_UNWINDER_ORC
548 /*
549 * Skip 3:
550 *
551 * function_trace_probe_call()
552 * ftrace_ops_assist_func()
553 * ftrace_call()
554 */
555 #define FTRACE_STACK_SKIP 3
556 #else
557 /*
558 * Skip 5:
559 *
560 * __trace_stack()
561 * ftrace_stacktrace()
562 * function_trace_probe_call()
563 * ftrace_ops_assist_func()
564 * ftrace_call()
565 */
566 #define FTRACE_STACK_SKIP 5
567 #endif
568
trace_stack(struct trace_array * tr)569 static __always_inline void trace_stack(struct trace_array *tr)
570 {
571 unsigned int trace_ctx;
572
573 trace_ctx = tracing_gen_ctx();
574
575 __trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP);
576 }
577
578 static void
ftrace_stacktrace(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)579 ftrace_stacktrace(unsigned long ip, unsigned long parent_ip,
580 struct trace_array *tr, struct ftrace_probe_ops *ops,
581 void *data)
582 {
583 trace_stack(tr);
584 }
585
586 static void
ftrace_stacktrace_count(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)587 ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip,
588 struct trace_array *tr, struct ftrace_probe_ops *ops,
589 void *data)
590 {
591 struct ftrace_func_mapper *mapper = data;
592 long *count;
593 long old_count;
594 long new_count;
595
596 if (!tracing_is_on())
597 return;
598
599 /* unlimited? */
600 if (!mapper) {
601 trace_stack(tr);
602 return;
603 }
604
605 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
606
607 /*
608 * Stack traces should only execute the number of times the
609 * user specified in the counter.
610 */
611 do {
612 old_count = *count;
613
614 if (!old_count)
615 return;
616
617 new_count = old_count - 1;
618 new_count = cmpxchg(count, old_count, new_count);
619 if (new_count == old_count)
620 trace_stack(tr);
621
622 if (!tracing_is_on())
623 return;
624
625 } while (new_count != old_count);
626 }
627
update_count(struct ftrace_probe_ops * ops,unsigned long ip,void * data)628 static int update_count(struct ftrace_probe_ops *ops, unsigned long ip,
629 void *data)
630 {
631 struct ftrace_func_mapper *mapper = data;
632 long *count = NULL;
633
634 if (mapper)
635 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
636
637 if (count) {
638 if (*count <= 0)
639 return 0;
640 (*count)--;
641 }
642
643 return 1;
644 }
645
646 static void
ftrace_dump_probe(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)647 ftrace_dump_probe(unsigned long ip, unsigned long parent_ip,
648 struct trace_array *tr, struct ftrace_probe_ops *ops,
649 void *data)
650 {
651 if (update_count(ops, ip, data))
652 ftrace_dump(DUMP_ALL);
653 }
654
655 /* Only dump the current CPU buffer. */
656 static void
ftrace_cpudump_probe(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)657 ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip,
658 struct trace_array *tr, struct ftrace_probe_ops *ops,
659 void *data)
660 {
661 if (update_count(ops, ip, data))
662 ftrace_dump(DUMP_ORIG);
663 }
664
665 static int
ftrace_probe_print(const char * name,struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)666 ftrace_probe_print(const char *name, struct seq_file *m,
667 unsigned long ip, struct ftrace_probe_ops *ops,
668 void *data)
669 {
670 struct ftrace_func_mapper *mapper = data;
671 long *count = NULL;
672
673 seq_printf(m, "%ps:%s", (void *)ip, name);
674
675 if (mapper)
676 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
677
678 if (count)
679 seq_printf(m, ":count=%ld\n", *count);
680 else
681 seq_puts(m, ":unlimited\n");
682
683 return 0;
684 }
685
686 static int
ftrace_traceon_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)687 ftrace_traceon_print(struct seq_file *m, unsigned long ip,
688 struct ftrace_probe_ops *ops,
689 void *data)
690 {
691 return ftrace_probe_print("traceon", m, ip, ops, data);
692 }
693
694 static int
ftrace_traceoff_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)695 ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
696 struct ftrace_probe_ops *ops, void *data)
697 {
698 return ftrace_probe_print("traceoff", m, ip, ops, data);
699 }
700
701 static int
ftrace_stacktrace_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)702 ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
703 struct ftrace_probe_ops *ops, void *data)
704 {
705 return ftrace_probe_print("stacktrace", m, ip, ops, data);
706 }
707
708 static int
ftrace_dump_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)709 ftrace_dump_print(struct seq_file *m, unsigned long ip,
710 struct ftrace_probe_ops *ops, void *data)
711 {
712 return ftrace_probe_print("dump", m, ip, ops, data);
713 }
714
715 static int
ftrace_cpudump_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)716 ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
717 struct ftrace_probe_ops *ops, void *data)
718 {
719 return ftrace_probe_print("cpudump", m, ip, ops, data);
720 }
721
722
723 static int
ftrace_count_init(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * init_data,void ** data)724 ftrace_count_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
725 unsigned long ip, void *init_data, void **data)
726 {
727 struct ftrace_func_mapper *mapper = *data;
728
729 if (!mapper) {
730 mapper = allocate_ftrace_func_mapper();
731 if (!mapper)
732 return -ENOMEM;
733 *data = mapper;
734 }
735
736 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
737 }
738
739 static void
ftrace_count_free(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * data)740 ftrace_count_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
741 unsigned long ip, void *data)
742 {
743 struct ftrace_func_mapper *mapper = data;
744
745 if (!ip) {
746 free_ftrace_func_mapper(mapper, NULL);
747 return;
748 }
749
750 ftrace_func_mapper_remove_ip(mapper, ip);
751 }
752
753 static struct ftrace_probe_ops traceon_count_probe_ops = {
754 .func = ftrace_traceon_count,
755 .print = ftrace_traceon_print,
756 .init = ftrace_count_init,
757 .free = ftrace_count_free,
758 };
759
760 static struct ftrace_probe_ops traceoff_count_probe_ops = {
761 .func = ftrace_traceoff_count,
762 .print = ftrace_traceoff_print,
763 .init = ftrace_count_init,
764 .free = ftrace_count_free,
765 };
766
767 static struct ftrace_probe_ops stacktrace_count_probe_ops = {
768 .func = ftrace_stacktrace_count,
769 .print = ftrace_stacktrace_print,
770 .init = ftrace_count_init,
771 .free = ftrace_count_free,
772 };
773
774 static struct ftrace_probe_ops dump_probe_ops = {
775 .func = ftrace_dump_probe,
776 .print = ftrace_dump_print,
777 .init = ftrace_count_init,
778 .free = ftrace_count_free,
779 };
780
781 static struct ftrace_probe_ops cpudump_probe_ops = {
782 .func = ftrace_cpudump_probe,
783 .print = ftrace_cpudump_print,
784 };
785
786 static struct ftrace_probe_ops traceon_probe_ops = {
787 .func = ftrace_traceon,
788 .print = ftrace_traceon_print,
789 };
790
791 static struct ftrace_probe_ops traceoff_probe_ops = {
792 .func = ftrace_traceoff,
793 .print = ftrace_traceoff_print,
794 };
795
796 static struct ftrace_probe_ops stacktrace_probe_ops = {
797 .func = ftrace_stacktrace,
798 .print = ftrace_stacktrace_print,
799 };
800
801 static int
ftrace_trace_probe_callback(struct trace_array * tr,struct ftrace_probe_ops * ops,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)802 ftrace_trace_probe_callback(struct trace_array *tr,
803 struct ftrace_probe_ops *ops,
804 struct ftrace_hash *hash, char *glob,
805 char *cmd, char *param, int enable)
806 {
807 void *count = (void *)-1;
808 char *number;
809 int ret;
810
811 /* hash funcs only work with set_ftrace_filter */
812 if (!enable)
813 return -EINVAL;
814
815 if (glob[0] == '!')
816 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
817
818 if (!param)
819 goto out_reg;
820
821 number = strsep(¶m, ":");
822
823 if (!strlen(number))
824 goto out_reg;
825
826 /*
827 * We use the callback data field (which is a pointer)
828 * as our counter.
829 */
830 ret = kstrtoul(number, 0, (unsigned long *)&count);
831 if (ret)
832 return ret;
833
834 out_reg:
835 ret = register_ftrace_function_probe(glob, tr, ops, count);
836
837 return ret < 0 ? ret : 0;
838 }
839
840 static int
ftrace_trace_onoff_callback(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)841 ftrace_trace_onoff_callback(struct trace_array *tr, struct ftrace_hash *hash,
842 char *glob, char *cmd, char *param, int enable)
843 {
844 struct ftrace_probe_ops *ops;
845
846 if (!tr)
847 return -ENODEV;
848
849 /* we register both traceon and traceoff to this callback */
850 if (strcmp(cmd, "traceon") == 0)
851 ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
852 else
853 ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;
854
855 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
856 param, enable);
857 }
858
859 static int
ftrace_stacktrace_callback(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)860 ftrace_stacktrace_callback(struct trace_array *tr, struct ftrace_hash *hash,
861 char *glob, char *cmd, char *param, int enable)
862 {
863 struct ftrace_probe_ops *ops;
864
865 if (!tr)
866 return -ENODEV;
867
868 ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;
869
870 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
871 param, enable);
872 }
873
874 static int
ftrace_dump_callback(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)875 ftrace_dump_callback(struct trace_array *tr, struct ftrace_hash *hash,
876 char *glob, char *cmd, char *param, int enable)
877 {
878 struct ftrace_probe_ops *ops;
879
880 if (!tr)
881 return -ENODEV;
882
883 ops = &dump_probe_ops;
884
885 /* Only dump once. */
886 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
887 "1", enable);
888 }
889
890 static int
ftrace_cpudump_callback(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)891 ftrace_cpudump_callback(struct trace_array *tr, struct ftrace_hash *hash,
892 char *glob, char *cmd, char *param, int enable)
893 {
894 struct ftrace_probe_ops *ops;
895
896 if (!tr)
897 return -ENODEV;
898
899 ops = &cpudump_probe_ops;
900
901 /* Only dump once. */
902 return ftrace_trace_probe_callback(tr, ops, hash, glob, cmd,
903 "1", enable);
904 }
905
906 static struct ftrace_func_command ftrace_traceon_cmd = {
907 .name = "traceon",
908 .func = ftrace_trace_onoff_callback,
909 };
910
911 static struct ftrace_func_command ftrace_traceoff_cmd = {
912 .name = "traceoff",
913 .func = ftrace_trace_onoff_callback,
914 };
915
916 static struct ftrace_func_command ftrace_stacktrace_cmd = {
917 .name = "stacktrace",
918 .func = ftrace_stacktrace_callback,
919 };
920
921 static struct ftrace_func_command ftrace_dump_cmd = {
922 .name = "dump",
923 .func = ftrace_dump_callback,
924 };
925
926 static struct ftrace_func_command ftrace_cpudump_cmd = {
927 .name = "cpudump",
928 .func = ftrace_cpudump_callback,
929 };
930
init_func_cmd_traceon(void)931 static int __init init_func_cmd_traceon(void)
932 {
933 int ret;
934
935 ret = register_ftrace_command(&ftrace_traceoff_cmd);
936 if (ret)
937 return ret;
938
939 ret = register_ftrace_command(&ftrace_traceon_cmd);
940 if (ret)
941 goto out_free_traceoff;
942
943 ret = register_ftrace_command(&ftrace_stacktrace_cmd);
944 if (ret)
945 goto out_free_traceon;
946
947 ret = register_ftrace_command(&ftrace_dump_cmd);
948 if (ret)
949 goto out_free_stacktrace;
950
951 ret = register_ftrace_command(&ftrace_cpudump_cmd);
952 if (ret)
953 goto out_free_dump;
954
955 return 0;
956
957 out_free_dump:
958 unregister_ftrace_command(&ftrace_dump_cmd);
959 out_free_stacktrace:
960 unregister_ftrace_command(&ftrace_stacktrace_cmd);
961 out_free_traceon:
962 unregister_ftrace_command(&ftrace_traceon_cmd);
963 out_free_traceoff:
964 unregister_ftrace_command(&ftrace_traceoff_cmd);
965
966 return ret;
967 }
968 #else
init_func_cmd_traceon(void)969 static inline int init_func_cmd_traceon(void)
970 {
971 return 0;
972 }
973 #endif /* CONFIG_DYNAMIC_FTRACE */
974
init_function_trace(void)975 __init int init_function_trace(void)
976 {
977 init_func_cmd_traceon();
978 return register_tracer(&function_trace);
979 }
980