1 /*
2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/kern/kern_intr.c,v 1.24.2.1 2001/10/14 20:05:50 luigi Exp $
27 *
28 */
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
33 #include <sys/kernel.h>
34 #include <sys/sysctl.h>
35 #include <sys/thread.h>
36 #include <sys/proc.h>
37 #include <sys/random.h>
38 #include <sys/serialize.h>
39 #include <sys/interrupt.h>
40 #include <sys/bus.h>
41 #include <sys/machintr.h>
42
43 #include <machine/frame.h>
44
45 #include <sys/thread2.h>
46 #include <sys/mplock2.h>
47
48 struct intr_info;
49
50 typedef struct intrec {
51 struct intrec *next;
52 struct intr_info *info;
53 inthand2_t *handler;
54 void *argument;
55 char *name;
56 int intr;
57 int intr_flags;
58 struct lwkt_serialize *serializer;
59 } *intrec_t;
60
61 struct intr_info {
62 intrec_t i_reclist;
63 struct thread *i_thread; /* don't embed struct thread */
64 struct random_softc i_random;
65 long i_count; /* interrupts dispatched */
66 int i_running;
67 short i_mplock_required;
68 short i_flags;
69 int i_fast;
70 int i_slow;
71 int i_state;
72 int i_errorticks;
73 unsigned long i_straycount;
74 int i_cpuid;
75 int i_intr;
76 };
77
78 struct intr_info_block {
79 struct intr_info ary[MAXCPU][MAX_INTS];
80 };
81
82 static struct intr_info_block *intr_block;
83 static struct intr_info *swi_info_ary[MAX_SOFTINTS];
84
85 static int max_installed_hard_intr[MAXCPU];
86
87 MALLOC_DEFINE(M_INTRMNG, "intrmng", "interrupt management");
88
89
90 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000
91
92 /*
93 * Assert that callers into interrupt handlers don't return with
94 * dangling tokens, spinlocks, or mp locks.
95 */
96 #ifdef INVARIANTS
97
98 #define TD_INVARIANTS_DECLARE \
99 int spincount; \
100 lwkt_tokref_t curstop
101
102 #define TD_INVARIANTS_GET(td) \
103 do { \
104 spincount = (td)->td_gd->gd_spinlocks; \
105 curstop = (td)->td_toks_stop; \
106 } while(0)
107
108 #define TD_INVARIANTS_TEST(td, name) \
109 do { \
110 KASSERT(spincount == (td)->td_gd->gd_spinlocks, \
111 ("spincount mismatch after interrupt handler %s", \
112 name)); \
113 KASSERT(curstop == (td)->td_toks_stop, \
114 ("token count mismatch after interrupt handler %s", \
115 name)); \
116 } while(0)
117
118 #else
119
120 /* !INVARIANTS */
121
122 #define TD_INVARIANTS_DECLARE
123 #define TD_INVARIANTS_GET(td)
124 #define TD_INVARIANTS_TEST(td, name)
125
126 #endif /* ndef INVARIANTS */
127
128 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS);
129 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS);
130 static void emergency_intr_timer_callback(systimer_t, int, struct intrframe *);
131 static void ithread_handler(void *arg);
132 static void ithread_emergency(void *arg);
133 static void report_stray_interrupt(struct intr_info *info, const char *func);
134 static void int_moveto_destcpu(int *, int);
135 static void int_moveto_origcpu(int, int);
136 static void sched_ithd_intern(struct intr_info *info);
137
138 static struct systimer emergency_intr_timer[MAXCPU];
139 static struct thread *emergency_intr_thread[MAXCPU];
140
141 #define ISTATE_NOTHREAD 0
142 #define ISTATE_NORMAL 1
143 #define ISTATE_LIVELOCKED 2
144
145 static int livelock_limit = 40000;
146 static int livelock_limit_hi = 120000;
147 static int livelock_lowater = 20000;
148 static int livelock_debug = -1;
149 SYSCTL_INT(_kern, OID_AUTO, livelock_limit,
150 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit");
151 SYSCTL_INT(_kern, OID_AUTO, livelock_limit_hi,
152 CTLFLAG_RW, &livelock_limit_hi, 0,
153 "Livelock interrupt rate limit (high frequency)");
154 SYSCTL_INT(_kern, OID_AUTO, livelock_lowater,
155 CTLFLAG_RW, &livelock_lowater, 0, "Livelock low-water mark restore");
156 SYSCTL_INT(_kern, OID_AUTO, livelock_debug,
157 CTLFLAG_RW, &livelock_debug, 0, "Livelock debug intr#");
158
159 static int emergency_intr_enable = 0; /* emergency interrupt polling */
160 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable);
161 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_enable, CTLTYPE_INT | CTLFLAG_RW,
162 0, 0, sysctl_emergency_enable, "I", "Emergency Interrupt Poll Enable");
163
164 static int emergency_intr_freq = 10; /* emergency polling frequency */
165 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq);
166 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_freq, CTLTYPE_INT | CTLFLAG_RW,
167 0, 0, sysctl_emergency_freq, "I", "Emergency Interrupt Poll Frequency");
168
169 /*
170 * Sysctl support routines
171 */
172 static int
sysctl_emergency_enable(SYSCTL_HANDLER_ARGS)173 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS)
174 {
175 int error, enabled, cpuid, freq, origcpu;
176
177 enabled = emergency_intr_enable;
178 error = sysctl_handle_int(oidp, &enabled, 0, req);
179 if (error || req->newptr == NULL)
180 return error;
181 emergency_intr_enable = enabled;
182 if (emergency_intr_enable)
183 freq = emergency_intr_freq;
184 else
185 freq = 1;
186
187 origcpu = mycpuid;
188 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
189 lwkt_migratecpu(cpuid);
190 systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq);
191 }
192 lwkt_migratecpu(origcpu);
193 return 0;
194 }
195
196 static int
sysctl_emergency_freq(SYSCTL_HANDLER_ARGS)197 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS)
198 {
199 int error, phz, cpuid, freq, origcpu;
200
201 phz = emergency_intr_freq;
202 error = sysctl_handle_int(oidp, &phz, 0, req);
203 if (error || req->newptr == NULL)
204 return error;
205 if (phz <= 0)
206 return EINVAL;
207 else if (phz > EMERGENCY_INTR_POLLING_FREQ_MAX)
208 phz = EMERGENCY_INTR_POLLING_FREQ_MAX;
209
210 emergency_intr_freq = phz;
211 if (emergency_intr_enable)
212 freq = emergency_intr_freq;
213 else
214 freq = 1;
215
216 origcpu = mycpuid;
217 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
218 lwkt_migratecpu(cpuid);
219 systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq);
220 }
221 lwkt_migratecpu(origcpu);
222 return 0;
223 }
224
225 /*
226 * Register an SWI or INTerrupt handler.
227 */
228 void *
register_swi(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)229 register_swi(int intr, inthand2_t *handler, void *arg, const char *name,
230 struct lwkt_serialize *serializer, int cpuid)
231 {
232 if (intr < FIRST_SOFTINT || intr >= MAX_INTS)
233 panic("register_swi: bad intr %d", intr);
234
235 if (cpuid < 0)
236 cpuid = intr % ncpus;
237 return(register_int(intr, handler, arg, name, serializer, 0, cpuid));
238 }
239
240 void *
register_swi_mp(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)241 register_swi_mp(int intr, inthand2_t *handler, void *arg, const char *name,
242 struct lwkt_serialize *serializer, int cpuid)
243 {
244 if (intr < FIRST_SOFTINT || intr >= MAX_INTS)
245 panic("register_swi: bad intr %d", intr);
246
247 if (cpuid < 0)
248 cpuid = intr % ncpus;
249 return(register_int(intr, handler, arg, name, serializer,
250 INTR_MPSAFE, cpuid));
251 }
252
253 void *
register_int(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags,int cpuid)254 register_int(int intr, inthand2_t *handler, void *arg, const char *name,
255 struct lwkt_serialize *serializer, int intr_flags, int cpuid)
256 {
257 struct intr_info *info;
258 struct intrec **list;
259 intrec_t rec = NULL;
260 int orig_cpuid;
261
262 KKASSERT(cpuid >= 0 && cpuid < ncpus);
263
264 if (intr < 0 || intr >= MAX_INTS)
265 panic("register_int: bad intr %d", intr);
266 if (name == NULL)
267 name = "???";
268 info = &intr_block->ary[cpuid][intr];
269
270 int_moveto_destcpu(&orig_cpuid, cpuid);
271
272 /*
273 * This intr has been registered as exclusive one, so
274 * it can't shared.
275 */
276 if (info->i_flags & INTR_EXCL)
277 goto done;
278
279 /*
280 * This intr has been registered as shared one, so it
281 * can't be used for exclusive handler.
282 */
283 list = &info->i_reclist;
284 if ((intr_flags & INTR_EXCL) && *list != NULL)
285 goto done;
286
287 /*
288 * Construct an interrupt handler record
289 */
290 rec = kmalloc(sizeof(struct intrec), M_DEVBUF, M_INTWAIT);
291 rec->name = kmalloc(strlen(name) + 1, M_DEVBUF, M_INTWAIT);
292 strcpy(rec->name, name);
293
294 rec->info = info;
295 rec->handler = handler;
296 rec->argument = arg;
297 rec->intr = intr;
298 rec->intr_flags = intr_flags;
299 rec->next = NULL;
300 rec->serializer = serializer;
301
302 /*
303 * Create an emergency polling thread and set up a systimer to wake
304 * it up. objcache isn't operational yet so use kmalloc.
305 *
306 * objcache may not be operational yet, use kmalloc().
307 */
308 if (emergency_intr_thread[cpuid] == NULL) {
309 emergency_intr_thread[cpuid] = kmalloc(sizeof(struct thread), M_DEVBUF,
310 M_INTWAIT | M_ZERO);
311 lwkt_create(ithread_emergency, NULL, NULL,
312 emergency_intr_thread[cpuid],
313 TDF_NOSTART | TDF_INTTHREAD, cpuid, "ithreadE %d",
314 cpuid);
315 systimer_init_periodic_nq(&emergency_intr_timer[cpuid],
316 emergency_intr_timer_callback,
317 emergency_intr_thread[cpuid],
318 (emergency_intr_enable ? emergency_intr_freq : 1));
319 }
320
321 /*
322 * Create an interrupt thread if necessary, leave it in an unscheduled
323 * state.
324 */
325 if (info->i_state == ISTATE_NOTHREAD) {
326 info->i_state = ISTATE_NORMAL;
327 info->i_thread = kmalloc(sizeof(struct thread), M_DEVBUF,
328 M_INTWAIT | M_ZERO);
329 lwkt_create(ithread_handler, (void *)(intptr_t)intr, NULL,
330 info->i_thread, TDF_NOSTART | TDF_INTTHREAD, cpuid,
331 "ithread%d %d", intr, cpuid);
332 if (intr >= FIRST_SOFTINT)
333 lwkt_setpri(info->i_thread, TDPRI_SOFT_NORM);
334 else
335 lwkt_setpri(info->i_thread, TDPRI_INT_MED);
336 info->i_thread->td_preemptable = lwkt_preempt;
337 }
338
339 /*
340 * Keep track of how many fast and slow interrupts we have.
341 * Set i_mplock_required if any handler in the chain requires
342 * the MP lock to operate.
343 */
344 if ((intr_flags & INTR_MPSAFE) == 0) {
345 info->i_mplock_required = 1;
346 kprintf("interrupt uses mplock: %s\n", name);
347 }
348 if (intr_flags & INTR_CLOCK) {
349 atomic_set_int(&info->i_thread->td_flags, TDF_CLKTHREAD);
350 ++info->i_fast;
351 } else {
352 ++info->i_slow;
353 }
354
355 info->i_flags |= (intr_flags & INTR_EXCL);
356 if (info->i_slow + info->i_fast == 1 && (intr_flags & INTR_HIFREQ)) {
357 /*
358 * Allow high frequency interrupt, if this intr is not
359 * shared yet.
360 */
361 info->i_flags |= INTR_HIFREQ;
362 } else {
363 info->i_flags &= ~INTR_HIFREQ;
364 }
365
366 /*
367 * Enable random number generation keying off of this interrupt.
368 */
369 if ((intr_flags & INTR_NOENTROPY) == 0 && info->i_random.sc_enabled == 0) {
370 info->i_random.sc_enabled = 1;
371 info->i_random.sc_intr = intr;
372 }
373
374 /*
375 * Add the record to the interrupt list.
376 */
377 crit_enter();
378 while (*list != NULL)
379 list = &(*list)->next;
380 *list = rec;
381 crit_exit();
382
383 /*
384 * Update max_installed_hard_intr to make the emergency intr poll
385 * a bit more efficient.
386 */
387 if (intr < FIRST_SOFTINT) {
388 if (max_installed_hard_intr[cpuid] <= intr)
389 max_installed_hard_intr[cpuid] = intr + 1;
390 }
391
392 if (intr >= FIRST_SOFTINT)
393 swi_info_ary[intr - FIRST_SOFTINT] = info;
394
395 /*
396 * Setup the machine level interrupt vector
397 */
398 if (intr < FIRST_SOFTINT && info->i_slow + info->i_fast == 1)
399 machintr_intr_setup(intr, intr_flags);
400
401 done:
402 int_moveto_origcpu(orig_cpuid, cpuid);
403 return(rec);
404 }
405
406 void
unregister_swi(void * id,int intr,int cpuid)407 unregister_swi(void *id, int intr, int cpuid)
408 {
409 if (cpuid < 0)
410 cpuid = intr % ncpus;
411
412 unregister_int(id, cpuid);
413 }
414
415 void
unregister_int(void * id,int cpuid)416 unregister_int(void *id, int cpuid)
417 {
418 struct intr_info *info;
419 struct intrec **list;
420 intrec_t rec;
421 int intr, orig_cpuid;
422
423 KKASSERT(cpuid >= 0 && cpuid < ncpus);
424
425 intr = ((intrec_t)id)->intr;
426
427 if (intr < 0 || intr >= MAX_INTS)
428 panic("register_int: bad intr %d", intr);
429
430 info = &intr_block->ary[cpuid][intr];
431
432 int_moveto_destcpu(&orig_cpuid, cpuid);
433
434 /*
435 * Remove the interrupt descriptor, adjust the descriptor count,
436 * and teardown the machine level vector if this was the last interrupt.
437 */
438 crit_enter();
439 list = &info->i_reclist;
440 while ((rec = *list) != NULL) {
441 if (rec == id)
442 break;
443 list = &rec->next;
444 }
445 if (rec) {
446 intrec_t rec0;
447
448 *list = rec->next;
449 if (rec->intr_flags & INTR_CLOCK)
450 --info->i_fast;
451 else
452 --info->i_slow;
453 if (intr < FIRST_SOFTINT && info->i_fast + info->i_slow == 0)
454 machintr_intr_teardown(intr);
455
456 /*
457 * Clear i_mplock_required if no handlers in the chain require the
458 * MP lock.
459 */
460 for (rec0 = info->i_reclist; rec0; rec0 = rec0->next) {
461 if ((rec0->intr_flags & INTR_MPSAFE) == 0)
462 break;
463 }
464 if (rec0 == NULL)
465 info->i_mplock_required = 0;
466 }
467
468 if (info->i_reclist == NULL) {
469 info->i_flags = 0;
470 if (intr >= FIRST_SOFTINT)
471 swi_info_ary[intr - FIRST_SOFTINT] = NULL;
472 } else if (info->i_fast + info->i_slow == 1 &&
473 (info->i_reclist->intr_flags & INTR_HIFREQ)) {
474 /* Unshared high frequency interrupt. */
475 info->i_flags |= INTR_HIFREQ;
476 }
477
478 crit_exit();
479
480 int_moveto_origcpu(orig_cpuid, cpuid);
481
482 /*
483 * Free the record.
484 */
485 if (rec != NULL) {
486 kfree(rec->name, M_DEVBUF);
487 kfree(rec, M_DEVBUF);
488 } else {
489 kprintf("warning: unregister_int: int %d handler for %s not found\n",
490 intr, ((intrec_t)id)->name);
491 }
492 }
493
494 long
get_interrupt_counter(int intr,int cpuid)495 get_interrupt_counter(int intr, int cpuid)
496 {
497 struct intr_info *info;
498
499 KKASSERT(cpuid >= 0 && cpuid < ncpus);
500
501 if (intr < 0 || intr >= MAX_INTS)
502 panic("register_int: bad intr %d", intr);
503 info = &intr_block->ary[cpuid][intr];
504 return(info->i_count);
505 }
506
507 void
register_randintr(int intr)508 register_randintr(int intr)
509 {
510 struct intr_info *info;
511 int cpuid;
512
513 if (intr < 0 || intr >= MAX_INTS)
514 panic("register_randintr: bad intr %d", intr);
515
516 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
517 info = &intr_block->ary[cpuid][intr];
518 info->i_random.sc_intr = intr;
519 info->i_random.sc_enabled = 1;
520 }
521 }
522
523 void
unregister_randintr(int intr)524 unregister_randintr(int intr)
525 {
526 struct intr_info *info;
527 int cpuid;
528
529 if (intr < 0 || intr >= MAX_INTS)
530 panic("register_swi: bad intr %d", intr);
531
532 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
533 info = &intr_block->ary[cpuid][intr];
534 info->i_random.sc_enabled = -1;
535 }
536 }
537
538 int
next_registered_randintr(int intr)539 next_registered_randintr(int intr)
540 {
541 struct intr_info *info;
542
543 if (intr < 0 || intr >= MAX_INTS)
544 panic("register_swi: bad intr %d", intr);
545
546 while (intr < MAX_INTS) {
547 int cpuid;
548
549 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
550 info = &intr_block->ary[cpuid][intr];
551 if (info->i_random.sc_enabled > 0)
552 return intr;
553 }
554 ++intr;
555 }
556 return intr;
557 }
558
559 /*
560 * Dispatch an interrupt. If there's nothing to do we have a stray
561 * interrupt and can just return, leaving the interrupt masked.
562 *
563 * We need to schedule the interrupt and set its i_running bit. If
564 * we are not on the interrupt thread's cpu we have to send a message
565 * to the correct cpu that will issue the desired action (interlocking
566 * with the interrupt thread's critical section). We do NOT attempt to
567 * reschedule interrupts whos i_running bit is already set because
568 * this would prematurely wakeup a livelock-limited interrupt thread.
569 *
570 * i_running is only tested/set on the same cpu as the interrupt thread.
571 *
572 * We are NOT in a critical section, which will allow the scheduled
573 * interrupt to preempt us. The MP lock might *NOT* be held here.
574 */
575 static void
sched_ithd_remote(void * arg)576 sched_ithd_remote(void *arg)
577 {
578 sched_ithd_intern(arg);
579 }
580
581 static void
sched_ithd_intern(struct intr_info * info)582 sched_ithd_intern(struct intr_info *info)
583 {
584 ++info->i_count;
585 if (info->i_state != ISTATE_NOTHREAD) {
586 if (info->i_reclist == NULL) {
587 report_stray_interrupt(info, "sched_ithd");
588 } else {
589 if (info->i_thread->td_gd == mycpu) {
590 if (info->i_running == 0) {
591 info->i_running = 1;
592 if (info->i_state != ISTATE_LIVELOCKED)
593 lwkt_schedule(info->i_thread); /* MIGHT PREEMPT */
594 }
595 } else {
596 lwkt_send_ipiq(info->i_thread->td_gd, sched_ithd_remote, info);
597 }
598 }
599 } else {
600 report_stray_interrupt(info, "sched_ithd");
601 }
602 }
603
604 void
sched_ithd_soft(int intr)605 sched_ithd_soft(int intr)
606 {
607 struct intr_info *info;
608
609 KKASSERT(intr >= FIRST_SOFTINT && intr < MAX_INTS);
610
611 info = swi_info_ary[intr - FIRST_SOFTINT];
612 if (info != NULL) {
613 sched_ithd_intern(info);
614 } else {
615 kprintf("unregistered softint %d got scheduled on cpu%d\n",
616 intr, mycpuid);
617 }
618 }
619
620 void
sched_ithd_hard(int intr)621 sched_ithd_hard(int intr)
622 {
623 KKASSERT(intr >= 0 && intr < MAX_HARDINTS);
624 sched_ithd_intern(&intr_block->ary[mycpuid][intr]);
625 }
626
627 #ifdef _KERNEL_VIRTUAL
628
629 void
sched_ithd_hard_virtual(int intr)630 sched_ithd_hard_virtual(int intr)
631 {
632 KKASSERT(intr >= 0 && intr < MAX_HARDINTS);
633 sched_ithd_intern(&intr_block->ary[0][intr]);
634 }
635
636 void *
register_int_virtual(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags)637 register_int_virtual(int intr, inthand2_t *handler, void *arg, const char *name,
638 struct lwkt_serialize *serializer, int intr_flags)
639 {
640 return register_int(intr, handler, arg, name, serializer, intr_flags, 0);
641 }
642
643 void
unregister_int_virtual(void * id)644 unregister_int_virtual(void *id)
645 {
646 unregister_int(id, 0);
647 }
648
649 #endif /* _KERN_VIRTUAL */
650
651 static void
report_stray_interrupt(struct intr_info * info,const char * func)652 report_stray_interrupt(struct intr_info *info, const char *func)
653 {
654 ++info->i_straycount;
655 if (info->i_straycount < 10) {
656 if (info->i_errorticks == ticks)
657 return;
658 info->i_errorticks = ticks;
659 kprintf("%s: stray interrupt %d on cpu%d\n",
660 func, info->i_intr, mycpuid);
661 } else if (info->i_straycount == 10) {
662 kprintf("%s: %ld stray interrupts %d on cpu%d - "
663 "there will be no further reports\n", func,
664 info->i_straycount, info->i_intr, mycpuid);
665 }
666 }
667
668 /*
669 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL
670 * might not be held).
671 */
672 static void
ithread_livelock_wakeup(systimer_t st,int in_ipi __unused,struct intrframe * frame __unused)673 ithread_livelock_wakeup(systimer_t st, int in_ipi __unused,
674 struct intrframe *frame __unused)
675 {
676 struct intr_info *info;
677
678 info = &intr_block->ary[mycpuid][(int)(intptr_t)st->data];
679 if (info->i_state != ISTATE_NOTHREAD)
680 lwkt_schedule(info->i_thread);
681 }
682
683 /*
684 * Schedule ithread within fast intr handler
685 *
686 * Temporarily bump the current thread's td_nest_count to prevent deep
687 * preemptions and splz/doreti stacks.
688 */
689 static __inline void
ithread_fast_sched(int intr,thread_t td)690 ithread_fast_sched(int intr, thread_t td)
691 {
692 ++td->td_nest_count;
693 crit_exit_quick(td);
694 sched_ithd_hard(intr);
695 crit_enter_quick(td);
696 --td->td_nest_count;
697 }
698
699 /*
700 * This function is called directly from the ICU or APIC vector code assembly
701 * to process an interrupt. The critical section and interrupt deferral
702 * checks have already been done but the function is entered WITHOUT
703 * a critical section held. The BGL may or may not be held.
704 *
705 * Must return non-zero if we do not want the vector code to re-enable
706 * the interrupt (which we don't if we have to schedule the interrupt)
707 */
708 int ithread_fast_handler(struct intrframe *frame);
709
710 int
ithread_fast_handler(struct intrframe * frame)711 ithread_fast_handler(struct intrframe *frame)
712 {
713 int intr;
714 struct intr_info *info;
715 struct intrec **list;
716 int must_schedule;
717 int got_mplock;
718 TD_INVARIANTS_DECLARE;
719 intrec_t rec, nrec;
720 globaldata_t gd;
721 thread_t td;
722
723 intr = frame->if_vec;
724 gd = mycpu;
725 td = curthread;
726
727 /* We must be in critical section. */
728 KKASSERT(td->td_critcount);
729
730 /* Race condition during early boot */
731 if (intr_block == NULL)
732 return 0;
733
734 info = &intr_block->ary[mycpuid][intr];
735
736 /*
737 * If we are not processing any FAST interrupts, just schedule the thing.
738 */
739 if (info->i_fast == 0) {
740 ++gd->gd_cnt.v_intr;
741 ithread_fast_sched(intr, td);
742 return(1);
743 }
744
745 /*
746 * This should not normally occur since interrupts ought to be
747 * masked if the ithread has been scheduled or is running.
748 */
749 if (info->i_running)
750 return(1);
751
752 /*
753 * Bump the interrupt nesting level to process any FAST interrupts.
754 * Obtain the MP lock as necessary. If the MP lock cannot be obtained,
755 * schedule the interrupt thread to deal with the issue instead.
756 *
757 * To reduce overhead, just leave the MP lock held once it has been
758 * obtained.
759 */
760 ++gd->gd_intr_nesting_level;
761 ++gd->gd_cnt.v_intr;
762 must_schedule = info->i_slow;
763 got_mplock = 0;
764
765 TD_INVARIANTS_GET(td);
766 list = &info->i_reclist;
767
768 for (rec = *list; rec; rec = nrec) {
769 /* rec may be invalid after call */
770 nrec = rec->next;
771
772 if (rec->intr_flags & INTR_CLOCK) {
773 if ((rec->intr_flags & INTR_MPSAFE) == 0 && got_mplock == 0) {
774 if (try_mplock() == 0) {
775 /* Couldn't get the MP lock; just schedule it. */
776 must_schedule = 1;
777 break;
778 }
779 got_mplock = 1;
780 }
781 if (rec->serializer) {
782 must_schedule += lwkt_serialize_handler_try(
783 rec->serializer, rec->handler,
784 rec->argument, frame);
785 } else {
786 rec->handler(rec->argument, frame);
787 }
788 TD_INVARIANTS_TEST(td, rec->name);
789 }
790 }
791
792 /*
793 * Cleanup
794 */
795 --gd->gd_intr_nesting_level;
796 if (got_mplock)
797 rel_mplock();
798
799 /*
800 * If we had a problem, or mixed fast and slow interrupt handlers are
801 * registered, schedule the ithread to catch the missed records (it
802 * will just re-run all of them). A return value of 0 indicates that
803 * all handlers have been run and the interrupt can be re-enabled, and
804 * a non-zero return indicates that the interrupt thread controls
805 * re-enablement.
806 */
807 if (must_schedule > 0)
808 ithread_fast_sched(intr, td);
809 else if (must_schedule == 0)
810 ++info->i_count;
811 return(must_schedule);
812 }
813
814 /*
815 * Interrupt threads run this as their main loop.
816 *
817 * The handler begins execution outside a critical section and no MP lock.
818 *
819 * The i_running state starts at 0. When an interrupt occurs, the hardware
820 * interrupt is disabled and sched_ithd_hard(). The HW interrupt remains
821 * disabled until all routines have run. We then call machintr_intr_enable()
822 * to reenable the HW interrupt and deschedule us until the next interrupt.
823 *
824 * We are responsible for atomically checking i_running. i_running for our
825 * irq is only set in the context of our cpu, so a critical section is a
826 * sufficient interlock.
827 */
828 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */
829
830 static void
ithread_handler(void * arg)831 ithread_handler(void *arg)
832 {
833 struct intr_info *info;
834 int use_limit;
835 uint32_t lseconds;
836 int intr, cpuid = mycpuid;
837 int mpheld;
838 struct intrec **list;
839 intrec_t rec, nrec;
840 globaldata_t gd;
841 struct systimer ill_timer; /* enforced freq. timer */
842 u_int ill_count; /* interrupt livelock counter */
843 int upper_limit; /* interrupt livelock upper limit */
844 TD_INVARIANTS_DECLARE;
845
846 ill_count = 0;
847 intr = (int)(intptr_t)arg;
848 info = &intr_block->ary[cpuid][intr];
849 list = &info->i_reclist;
850
851 /*
852 * The loop must be entered with one critical section held. The thread
853 * does not hold the mplock on startup.
854 */
855 gd = mycpu;
856 lseconds = gd->gd_time_seconds;
857 crit_enter_gd(gd);
858 mpheld = 0;
859
860 for (;;) {
861 /*
862 * The chain is only considered MPSAFE if all its interrupt handlers
863 * are MPSAFE. However, if intr_mpsafe has been turned off we
864 * always operate with the BGL.
865 */
866 if (info->i_mplock_required != mpheld) {
867 if (info->i_mplock_required) {
868 KKASSERT(mpheld == 0);
869 get_mplock();
870 mpheld = 1;
871 } else {
872 KKASSERT(mpheld != 0);
873 rel_mplock();
874 mpheld = 0;
875 }
876 }
877
878 TD_INVARIANTS_GET(gd->gd_curthread);
879
880 /*
881 * If an interrupt is pending, clear i_running and execute the
882 * handlers. Note that certain types of interrupts can re-trigger
883 * and set i_running again.
884 *
885 * Each handler is run in a critical section. Note that we run both
886 * FAST and SLOW designated service routines.
887 */
888 if (info->i_running) {
889 ++ill_count;
890 info->i_running = 0;
891
892 if (*list == NULL)
893 report_stray_interrupt(info, "ithread_handler");
894
895 for (rec = *list; rec; rec = nrec) {
896 /* rec may be invalid after call */
897 nrec = rec->next;
898 if (rec->handler == NULL) {
899 kprintf("NULL HANDLER %s\n", rec->name);
900 } else
901 if (rec->serializer) {
902 lwkt_serialize_handler_call(rec->serializer, rec->handler,
903 rec->argument, NULL);
904 } else {
905 rec->handler(rec->argument, NULL);
906 }
907 TD_INVARIANTS_TEST(gd->gd_curthread, rec->name);
908 }
909 }
910
911 /*
912 * This is our interrupt hook to add rate randomness to the random
913 * number generator.
914 */
915 if (info->i_random.sc_enabled > 0)
916 add_interrupt_randomness(intr);
917
918 /*
919 * Unmask the interrupt to allow it to trigger again. This only
920 * applies to certain types of interrupts (typ level interrupts).
921 * This can result in the interrupt retriggering, but the retrigger
922 * will not be processed until we cycle our critical section.
923 *
924 * Only unmask interrupts while handlers are installed. It is
925 * possible to hit a situation where no handlers are installed
926 * due to a device driver livelocking and then tearing down its
927 * interrupt on close (the parallel bus being a good example).
928 */
929 if (intr < FIRST_SOFTINT && *list)
930 machintr_intr_enable(intr);
931
932 /*
933 * Do a quick exit/enter to catch any higher-priority interrupt
934 * sources, such as the statclock, so thread time accounting
935 * will still work. This may also cause an interrupt to re-trigger.
936 */
937 crit_exit_gd(gd);
938 crit_enter_gd(gd);
939
940 /*
941 * LIVELOCK STATE MACHINE
942 */
943 switch(info->i_state) {
944 case ISTATE_NORMAL:
945 /*
946 * Reset the count each second.
947 */
948 if (lseconds != gd->gd_time_seconds) {
949 lseconds = gd->gd_time_seconds;
950 ill_count = 0;
951 }
952
953 /*
954 * If we did not exceed the frequency limit, we are done.
955 * If the interrupt has not retriggered we deschedule ourselves.
956 */
957 if (info->i_flags & INTR_HIFREQ)
958 upper_limit = livelock_limit_hi;
959 else
960 upper_limit = livelock_limit;
961 if (ill_count <= upper_limit) {
962 if (info->i_running == 0) {
963 lwkt_deschedule_self(gd->gd_curthread);
964 lwkt_switch();
965 }
966 break;
967 }
968
969 /*
970 * Otherwise we are livelocked. Set up a periodic systimer
971 * to wake the thread up at the limit frequency.
972 */
973 kprintf("intr %d on cpu%d at %d/%d hz, livelocked limit engaged!\n",
974 intr, cpuid, ill_count, upper_limit);
975 info->i_state = ISTATE_LIVELOCKED;
976 if ((use_limit = upper_limit) < 100)
977 use_limit = 100;
978 else if (use_limit > 500000)
979 use_limit = 500000;
980 systimer_init_periodic_nq(&ill_timer, ithread_livelock_wakeup,
981 (void *)(intptr_t)intr, use_limit);
982 /* fall through */
983 case ISTATE_LIVELOCKED:
984 /*
985 * Wait for our periodic timer to go off. Since the interrupt
986 * has re-armed it can still set i_running, but it will not
987 * reschedule us while we are in a livelocked state.
988 */
989 lwkt_deschedule_self(gd->gd_curthread);
990 lwkt_switch();
991
992 /*
993 * Check once a second to see if the livelock condition no
994 * longer applies.
995 */
996 if (lseconds != gd->gd_time_seconds) {
997 lseconds = gd->gd_time_seconds;
998 if (ill_count < livelock_lowater) {
999 info->i_state = ISTATE_NORMAL;
1000 systimer_del(&ill_timer);
1001 kprintf("intr %d on cpu%d at %d/%d hz, livelock removed\n",
1002 intr, cpuid, ill_count, livelock_lowater);
1003 } else if (livelock_debug == intr ||
1004 (bootverbose && cold)) {
1005 kprintf("intr %d on cpu%d at %d/%d hz, in livelock\n",
1006 intr, cpuid, ill_count, livelock_lowater);
1007 }
1008 ill_count = 0;
1009 }
1010 break;
1011 }
1012 }
1013 /* NOT REACHED */
1014 }
1015
1016 /*
1017 * Emergency interrupt polling thread. The thread begins execution
1018 * outside a critical section with the BGL held.
1019 *
1020 * If emergency interrupt polling is enabled, this thread will
1021 * execute all system interrupts not marked INTR_NOPOLL at the
1022 * specified polling frequency.
1023 *
1024 * WARNING! This thread runs *ALL* interrupt service routines that
1025 * are not marked INTR_NOPOLL, which basically means everything except
1026 * the 8254 clock interrupt and the ATA interrupt. It has very high
1027 * overhead and should only be used in situations where the machine
1028 * cannot otherwise be made to work. Due to the severe performance
1029 * degredation, it should not be enabled on production machines.
1030 */
1031 static void
ithread_emergency(void * arg __unused)1032 ithread_emergency(void *arg __unused)
1033 {
1034 globaldata_t gd = mycpu;
1035 struct intr_info *info;
1036 intrec_t rec, nrec;
1037 int intr, cpuid = mycpuid;
1038 TD_INVARIANTS_DECLARE;
1039
1040 get_mplock();
1041 crit_enter_gd(gd);
1042 TD_INVARIANTS_GET(gd->gd_curthread);
1043
1044 for (;;) {
1045 for (intr = 0; intr < max_installed_hard_intr[cpuid]; ++intr) {
1046 info = &intr_block->ary[cpuid][intr];
1047 for (rec = info->i_reclist; rec; rec = nrec) {
1048 /* rec may be invalid after call */
1049 nrec = rec->next;
1050 if ((rec->intr_flags & INTR_NOPOLL) == 0) {
1051 if (rec->serializer) {
1052 lwkt_serialize_handler_try(rec->serializer,
1053 rec->handler, rec->argument, NULL);
1054 } else {
1055 rec->handler(rec->argument, NULL);
1056 }
1057 TD_INVARIANTS_TEST(gd->gd_curthread, rec->name);
1058 }
1059 }
1060 }
1061 lwkt_deschedule_self(gd->gd_curthread);
1062 lwkt_switch();
1063 }
1064 /* NOT REACHED */
1065 }
1066
1067 /*
1068 * Systimer callback - schedule the emergency interrupt poll thread
1069 * if emergency polling is enabled.
1070 */
1071 static
1072 void
emergency_intr_timer_callback(systimer_t info,int in_ipi __unused,struct intrframe * frame __unused)1073 emergency_intr_timer_callback(systimer_t info, int in_ipi __unused,
1074 struct intrframe *frame __unused)
1075 {
1076 if (emergency_intr_enable)
1077 lwkt_schedule(info->data);
1078 }
1079
1080 /*
1081 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1082 * The data for this machine dependent, and the declarations are in machine
1083 * dependent code. The layout of intrnames and intrcnt however is machine
1084 * independent.
1085 *
1086 * We do not know the length of intrcnt and intrnames at compile time, so
1087 * calculate things at run time.
1088 */
1089
1090 static int
sysctl_intrnames(SYSCTL_HANDLER_ARGS)1091 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1092 {
1093 struct intr_info *info;
1094 intrec_t rec;
1095 int error = 0;
1096 int len;
1097 int intr, cpuid;
1098 char buf[64];
1099
1100 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1101 for (intr = 0; error == 0 && intr < MAX_INTS; ++intr) {
1102 info = &intr_block->ary[cpuid][intr];
1103
1104 len = 0;
1105 buf[0] = 0;
1106 for (rec = info->i_reclist; rec; rec = rec->next) {
1107 ksnprintf(buf + len, sizeof(buf) - len, "%s%s",
1108 (len ? "/" : ""), rec->name);
1109 len += strlen(buf + len);
1110 }
1111 if (len == 0) {
1112 ksnprintf(buf, sizeof(buf), "irq%d", intr);
1113 len = strlen(buf);
1114 }
1115 error = SYSCTL_OUT(req, buf, len + 1);
1116 }
1117 }
1118 return (error);
1119 }
1120
1121 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1122 NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1123
1124 static int
sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS)1125 sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS)
1126 {
1127 struct intr_info *info;
1128 int error = 0;
1129 int intr, cpuid;
1130
1131 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1132 for (intr = 0; intr < MAX_INTS; ++intr) {
1133 info = &intr_block->ary[cpuid][intr];
1134
1135 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count));
1136 if (error)
1137 goto failed;
1138 }
1139 }
1140 failed:
1141 return(error);
1142 }
1143
1144 SYSCTL_PROC(_hw, OID_AUTO, intrcnt_all, CTLTYPE_OPAQUE | CTLFLAG_RD,
1145 NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts");
1146
1147 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1148 NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts");
1149
1150 static void
int_moveto_destcpu(int * orig_cpuid0,int cpuid)1151 int_moveto_destcpu(int *orig_cpuid0, int cpuid)
1152 {
1153 int orig_cpuid = mycpuid;
1154
1155 if (cpuid != orig_cpuid)
1156 lwkt_migratecpu(cpuid);
1157
1158 *orig_cpuid0 = orig_cpuid;
1159 }
1160
1161 static void
int_moveto_origcpu(int orig_cpuid,int cpuid)1162 int_moveto_origcpu(int orig_cpuid, int cpuid)
1163 {
1164 if (cpuid != orig_cpuid)
1165 lwkt_migratecpu(orig_cpuid);
1166 }
1167
1168 static void
intr_init(void * dummy __unused)1169 intr_init(void *dummy __unused)
1170 {
1171 int cpuid;
1172
1173 kprintf("Initialize MI interrupts for %d cpus\n", ncpus);
1174
1175 intr_block = kmalloc(offsetof(struct intr_info_block, ary[ncpus][0]),
1176 M_INTRMNG, M_INTWAIT | M_ZERO);
1177
1178 for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1179 int intr;
1180
1181 for (intr = 0; intr < MAX_INTS; ++intr) {
1182 struct intr_info *info = &intr_block->ary[cpuid][intr];
1183
1184 info->i_cpuid = cpuid;
1185 info->i_intr = intr;
1186 }
1187 }
1188 }
1189 SYSINIT(intr_init, SI_BOOT2_FINISH_PIC, SI_ORDER_ANY, intr_init, NULL);
1190