FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_intr.c
1 /*-
2 * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
3 * 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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/10.1/sys/kern/kern_intr.c 256381 2013-10-12 15:31:36Z markm $");
29
30 #include "opt_ddb.h"
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/conf.h>
35 #include <sys/cpuset.h>
36 #include <sys/rtprio.h>
37 #include <sys/systm.h>
38 #include <sys/interrupt.h>
39 #include <sys/kernel.h>
40 #include <sys/kthread.h>
41 #include <sys/ktr.h>
42 #include <sys/limits.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/mutex.h>
46 #include <sys/priv.h>
47 #include <sys/proc.h>
48 #include <sys/random.h>
49 #include <sys/resourcevar.h>
50 #include <sys/sched.h>
51 #include <sys/smp.h>
52 #include <sys/sysctl.h>
53 #include <sys/syslog.h>
54 #include <sys/unistd.h>
55 #include <sys/vmmeter.h>
56 #include <machine/atomic.h>
57 #include <machine/cpu.h>
58 #include <machine/md_var.h>
59 #include <machine/stdarg.h>
60 #ifdef DDB
61 #include <ddb/ddb.h>
62 #include <ddb/db_sym.h>
63 #endif
64
65 /*
66 * Describe an interrupt thread. There is one of these per interrupt event.
67 */
68 struct intr_thread {
69 struct intr_event *it_event;
70 struct thread *it_thread; /* Kernel thread. */
71 int it_flags; /* (j) IT_* flags. */
72 int it_need; /* Needs service. */
73 };
74
75 /* Interrupt thread flags kept in it_flags */
76 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */
77 #define IT_WAIT 0x000002 /* Thread is waiting for completion. */
78
79 struct intr_entropy {
80 struct thread *td;
81 uintptr_t event;
82 };
83
84 struct intr_event *clk_intr_event;
85 struct intr_event *tty_intr_event;
86 void *vm_ih;
87 struct proc *intrproc;
88
89 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
90
91 static int intr_storm_threshold = 1000;
92 TUNABLE_INT("hw.intr_storm_threshold", &intr_storm_threshold);
93 SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RW,
94 &intr_storm_threshold, 0,
95 "Number of consecutive interrupts before storm protection is enabled");
96 static TAILQ_HEAD(, intr_event) event_list =
97 TAILQ_HEAD_INITIALIZER(event_list);
98 static struct mtx event_lock;
99 MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF);
100
101 static void intr_event_update(struct intr_event *ie);
102 #ifdef INTR_FILTER
103 static int intr_event_schedule_thread(struct intr_event *ie,
104 struct intr_thread *ithd);
105 static int intr_filter_loop(struct intr_event *ie,
106 struct trapframe *frame, struct intr_thread **ithd);
107 static struct intr_thread *ithread_create(const char *name,
108 struct intr_handler *ih);
109 #else
110 static int intr_event_schedule_thread(struct intr_event *ie);
111 static struct intr_thread *ithread_create(const char *name);
112 #endif
113 static void ithread_destroy(struct intr_thread *ithread);
114 static void ithread_execute_handlers(struct proc *p,
115 struct intr_event *ie);
116 #ifdef INTR_FILTER
117 static void priv_ithread_execute_handler(struct proc *p,
118 struct intr_handler *ih);
119 #endif
120 static void ithread_loop(void *);
121 static void ithread_update(struct intr_thread *ithd);
122 static void start_softintr(void *);
123
124 /* Map an interrupt type to an ithread priority. */
125 u_char
126 intr_priority(enum intr_type flags)
127 {
128 u_char pri;
129
130 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
131 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
132 switch (flags) {
133 case INTR_TYPE_TTY:
134 pri = PI_TTY;
135 break;
136 case INTR_TYPE_BIO:
137 pri = PI_DISK;
138 break;
139 case INTR_TYPE_NET:
140 pri = PI_NET;
141 break;
142 case INTR_TYPE_CAM:
143 pri = PI_DISK;
144 break;
145 case INTR_TYPE_AV:
146 pri = PI_AV;
147 break;
148 case INTR_TYPE_CLK:
149 pri = PI_REALTIME;
150 break;
151 case INTR_TYPE_MISC:
152 pri = PI_DULL; /* don't care */
153 break;
154 default:
155 /* We didn't specify an interrupt level. */
156 panic("intr_priority: no interrupt type in flags");
157 }
158
159 return pri;
160 }
161
162 /*
163 * Update an ithread based on the associated intr_event.
164 */
165 static void
166 ithread_update(struct intr_thread *ithd)
167 {
168 struct intr_event *ie;
169 struct thread *td;
170 u_char pri;
171
172 ie = ithd->it_event;
173 td = ithd->it_thread;
174
175 /* Determine the overall priority of this event. */
176 if (TAILQ_EMPTY(&ie->ie_handlers))
177 pri = PRI_MAX_ITHD;
178 else
179 pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri;
180
181 /* Update name and priority. */
182 strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
183 #ifdef KTR
184 sched_clear_tdname(td);
185 #endif
186 thread_lock(td);
187 sched_prio(td, pri);
188 thread_unlock(td);
189 }
190
191 /*
192 * Regenerate the full name of an interrupt event and update its priority.
193 */
194 static void
195 intr_event_update(struct intr_event *ie)
196 {
197 struct intr_handler *ih;
198 char *last;
199 int missed, space;
200
201 /* Start off with no entropy and just the name of the event. */
202 mtx_assert(&ie->ie_lock, MA_OWNED);
203 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
204 ie->ie_flags &= ~IE_ENTROPY;
205 missed = 0;
206 space = 1;
207
208 /* Run through all the handlers updating values. */
209 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
210 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
211 sizeof(ie->ie_fullname)) {
212 strcat(ie->ie_fullname, " ");
213 strcat(ie->ie_fullname, ih->ih_name);
214 space = 0;
215 } else
216 missed++;
217 if (ih->ih_flags & IH_ENTROPY)
218 ie->ie_flags |= IE_ENTROPY;
219 }
220
221 /*
222 * If the handler names were too long, add +'s to indicate missing
223 * names. If we run out of room and still have +'s to add, change
224 * the last character from a + to a *.
225 */
226 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
227 while (missed-- > 0) {
228 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
229 if (*last == '+') {
230 *last = '*';
231 break;
232 } else
233 *last = '+';
234 } else if (space) {
235 strcat(ie->ie_fullname, " +");
236 space = 0;
237 } else
238 strcat(ie->ie_fullname, "+");
239 }
240
241 /*
242 * If this event has an ithread, update it's priority and
243 * name.
244 */
245 if (ie->ie_thread != NULL)
246 ithread_update(ie->ie_thread);
247 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
248 }
249
250 int
251 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
252 void (*pre_ithread)(void *), void (*post_ithread)(void *),
253 void (*post_filter)(void *), int (*assign_cpu)(void *, u_char),
254 const char *fmt, ...)
255 {
256 struct intr_event *ie;
257 va_list ap;
258
259 /* The only valid flag during creation is IE_SOFT. */
260 if ((flags & ~IE_SOFT) != 0)
261 return (EINVAL);
262 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
263 ie->ie_source = source;
264 ie->ie_pre_ithread = pre_ithread;
265 ie->ie_post_ithread = post_ithread;
266 ie->ie_post_filter = post_filter;
267 ie->ie_assign_cpu = assign_cpu;
268 ie->ie_flags = flags;
269 ie->ie_irq = irq;
270 ie->ie_cpu = NOCPU;
271 TAILQ_INIT(&ie->ie_handlers);
272 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
273
274 va_start(ap, fmt);
275 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
276 va_end(ap);
277 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
278 mtx_lock(&event_lock);
279 TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
280 mtx_unlock(&event_lock);
281 if (event != NULL)
282 *event = ie;
283 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
284 return (0);
285 }
286
287 /*
288 * Bind an interrupt event to the specified CPU. Note that not all
289 * platforms support binding an interrupt to a CPU. For those
290 * platforms this request will fail. For supported platforms, any
291 * associated ithreads as well as the primary interrupt context will
292 * be bound to the specificed CPU. Using a cpu id of NOCPU unbinds
293 * the interrupt event.
294 */
295 int
296 intr_event_bind(struct intr_event *ie, u_char cpu)
297 {
298 cpuset_t mask;
299 lwpid_t id;
300 int error;
301
302 /* Need a CPU to bind to. */
303 if (cpu != NOCPU && CPU_ABSENT(cpu))
304 return (EINVAL);
305
306 if (ie->ie_assign_cpu == NULL)
307 return (EOPNOTSUPP);
308
309 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
310 if (error)
311 return (error);
312
313 /*
314 * If we have any ithreads try to set their mask first to verify
315 * permissions, etc.
316 */
317 mtx_lock(&ie->ie_lock);
318 if (ie->ie_thread != NULL) {
319 CPU_ZERO(&mask);
320 if (cpu == NOCPU)
321 CPU_COPY(cpuset_root, &mask);
322 else
323 CPU_SET(cpu, &mask);
324 id = ie->ie_thread->it_thread->td_tid;
325 mtx_unlock(&ie->ie_lock);
326 error = cpuset_setthread(id, &mask);
327 if (error)
328 return (error);
329 } else
330 mtx_unlock(&ie->ie_lock);
331 error = ie->ie_assign_cpu(ie->ie_source, cpu);
332 if (error) {
333 mtx_lock(&ie->ie_lock);
334 if (ie->ie_thread != NULL) {
335 CPU_ZERO(&mask);
336 if (ie->ie_cpu == NOCPU)
337 CPU_COPY(cpuset_root, &mask);
338 else
339 CPU_SET(ie->ie_cpu, &mask);
340 id = ie->ie_thread->it_thread->td_tid;
341 mtx_unlock(&ie->ie_lock);
342 (void)cpuset_setthread(id, &mask);
343 } else
344 mtx_unlock(&ie->ie_lock);
345 return (error);
346 }
347
348 mtx_lock(&ie->ie_lock);
349 ie->ie_cpu = cpu;
350 mtx_unlock(&ie->ie_lock);
351
352 return (error);
353 }
354
355 static struct intr_event *
356 intr_lookup(int irq)
357 {
358 struct intr_event *ie;
359
360 mtx_lock(&event_lock);
361 TAILQ_FOREACH(ie, &event_list, ie_list)
362 if (ie->ie_irq == irq &&
363 (ie->ie_flags & IE_SOFT) == 0 &&
364 TAILQ_FIRST(&ie->ie_handlers) != NULL)
365 break;
366 mtx_unlock(&event_lock);
367 return (ie);
368 }
369
370 int
371 intr_setaffinity(int irq, void *m)
372 {
373 struct intr_event *ie;
374 cpuset_t *mask;
375 u_char cpu;
376 int n;
377
378 mask = m;
379 cpu = NOCPU;
380 /*
381 * If we're setting all cpus we can unbind. Otherwise make sure
382 * only one cpu is in the set.
383 */
384 if (CPU_CMP(cpuset_root, mask)) {
385 for (n = 0; n < CPU_SETSIZE; n++) {
386 if (!CPU_ISSET(n, mask))
387 continue;
388 if (cpu != NOCPU)
389 return (EINVAL);
390 cpu = (u_char)n;
391 }
392 }
393 ie = intr_lookup(irq);
394 if (ie == NULL)
395 return (ESRCH);
396 return (intr_event_bind(ie, cpu));
397 }
398
399 int
400 intr_getaffinity(int irq, void *m)
401 {
402 struct intr_event *ie;
403 cpuset_t *mask;
404
405 mask = m;
406 ie = intr_lookup(irq);
407 if (ie == NULL)
408 return (ESRCH);
409 CPU_ZERO(mask);
410 mtx_lock(&ie->ie_lock);
411 if (ie->ie_cpu == NOCPU)
412 CPU_COPY(cpuset_root, mask);
413 else
414 CPU_SET(ie->ie_cpu, mask);
415 mtx_unlock(&ie->ie_lock);
416 return (0);
417 }
418
419 int
420 intr_event_destroy(struct intr_event *ie)
421 {
422
423 mtx_lock(&event_lock);
424 mtx_lock(&ie->ie_lock);
425 if (!TAILQ_EMPTY(&ie->ie_handlers)) {
426 mtx_unlock(&ie->ie_lock);
427 mtx_unlock(&event_lock);
428 return (EBUSY);
429 }
430 TAILQ_REMOVE(&event_list, ie, ie_list);
431 #ifndef notyet
432 if (ie->ie_thread != NULL) {
433 ithread_destroy(ie->ie_thread);
434 ie->ie_thread = NULL;
435 }
436 #endif
437 mtx_unlock(&ie->ie_lock);
438 mtx_unlock(&event_lock);
439 mtx_destroy(&ie->ie_lock);
440 free(ie, M_ITHREAD);
441 return (0);
442 }
443
444 #ifndef INTR_FILTER
445 static struct intr_thread *
446 ithread_create(const char *name)
447 {
448 struct intr_thread *ithd;
449 struct thread *td;
450 int error;
451
452 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
453
454 error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
455 &td, RFSTOPPED | RFHIGHPID,
456 0, "intr", "%s", name);
457 if (error)
458 panic("kproc_create() failed with %d", error);
459 thread_lock(td);
460 sched_class(td, PRI_ITHD);
461 TD_SET_IWAIT(td);
462 thread_unlock(td);
463 td->td_pflags |= TDP_ITHREAD;
464 ithd->it_thread = td;
465 CTR2(KTR_INTR, "%s: created %s", __func__, name);
466 return (ithd);
467 }
468 #else
469 static struct intr_thread *
470 ithread_create(const char *name, struct intr_handler *ih)
471 {
472 struct intr_thread *ithd;
473 struct thread *td;
474 int error;
475
476 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
477
478 error = kproc_kthread_add(ithread_loop, ih, &intrproc,
479 &td, RFSTOPPED | RFHIGHPID,
480 0, "intr", "%s", name);
481 if (error)
482 panic("kproc_create() failed with %d", error);
483 thread_lock(td);
484 sched_class(td, PRI_ITHD);
485 TD_SET_IWAIT(td);
486 thread_unlock(td);
487 td->td_pflags |= TDP_ITHREAD;
488 ithd->it_thread = td;
489 CTR2(KTR_INTR, "%s: created %s", __func__, name);
490 return (ithd);
491 }
492 #endif
493
494 static void
495 ithread_destroy(struct intr_thread *ithread)
496 {
497 struct thread *td;
498
499 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
500 td = ithread->it_thread;
501 thread_lock(td);
502 ithread->it_flags |= IT_DEAD;
503 if (TD_AWAITING_INTR(td)) {
504 TD_CLR_IWAIT(td);
505 sched_add(td, SRQ_INTR);
506 }
507 thread_unlock(td);
508 }
509
510 #ifndef INTR_FILTER
511 int
512 intr_event_add_handler(struct intr_event *ie, const char *name,
513 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
514 enum intr_type flags, void **cookiep)
515 {
516 struct intr_handler *ih, *temp_ih;
517 struct intr_thread *it;
518
519 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
520 return (EINVAL);
521
522 /* Allocate and populate an interrupt handler structure. */
523 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
524 ih->ih_filter = filter;
525 ih->ih_handler = handler;
526 ih->ih_argument = arg;
527 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
528 ih->ih_event = ie;
529 ih->ih_pri = pri;
530 if (flags & INTR_EXCL)
531 ih->ih_flags = IH_EXCLUSIVE;
532 if (flags & INTR_MPSAFE)
533 ih->ih_flags |= IH_MPSAFE;
534 if (flags & INTR_ENTROPY)
535 ih->ih_flags |= IH_ENTROPY;
536
537 /* We can only have one exclusive handler in a event. */
538 mtx_lock(&ie->ie_lock);
539 if (!TAILQ_EMPTY(&ie->ie_handlers)) {
540 if ((flags & INTR_EXCL) ||
541 (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
542 mtx_unlock(&ie->ie_lock);
543 free(ih, M_ITHREAD);
544 return (EINVAL);
545 }
546 }
547
548 /* Create a thread if we need one. */
549 while (ie->ie_thread == NULL && handler != NULL) {
550 if (ie->ie_flags & IE_ADDING_THREAD)
551 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
552 else {
553 ie->ie_flags |= IE_ADDING_THREAD;
554 mtx_unlock(&ie->ie_lock);
555 it = ithread_create("intr: newborn");
556 mtx_lock(&ie->ie_lock);
557 ie->ie_flags &= ~IE_ADDING_THREAD;
558 ie->ie_thread = it;
559 it->it_event = ie;
560 ithread_update(it);
561 wakeup(ie);
562 }
563 }
564
565 /* Add the new handler to the event in priority order. */
566 TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
567 if (temp_ih->ih_pri > ih->ih_pri)
568 break;
569 }
570 if (temp_ih == NULL)
571 TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
572 else
573 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
574 intr_event_update(ie);
575
576 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
577 ie->ie_name);
578 mtx_unlock(&ie->ie_lock);
579
580 if (cookiep != NULL)
581 *cookiep = ih;
582 return (0);
583 }
584 #else
585 int
586 intr_event_add_handler(struct intr_event *ie, const char *name,
587 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
588 enum intr_type flags, void **cookiep)
589 {
590 struct intr_handler *ih, *temp_ih;
591 struct intr_thread *it;
592
593 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
594 return (EINVAL);
595
596 /* Allocate and populate an interrupt handler structure. */
597 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
598 ih->ih_filter = filter;
599 ih->ih_handler = handler;
600 ih->ih_argument = arg;
601 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
602 ih->ih_event = ie;
603 ih->ih_pri = pri;
604 if (flags & INTR_EXCL)
605 ih->ih_flags = IH_EXCLUSIVE;
606 if (flags & INTR_MPSAFE)
607 ih->ih_flags |= IH_MPSAFE;
608 if (flags & INTR_ENTROPY)
609 ih->ih_flags |= IH_ENTROPY;
610
611 /* We can only have one exclusive handler in a event. */
612 mtx_lock(&ie->ie_lock);
613 if (!TAILQ_EMPTY(&ie->ie_handlers)) {
614 if ((flags & INTR_EXCL) ||
615 (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
616 mtx_unlock(&ie->ie_lock);
617 free(ih, M_ITHREAD);
618 return (EINVAL);
619 }
620 }
621
622 /* For filtered handlers, create a private ithread to run on. */
623 if (filter != NULL && handler != NULL) {
624 mtx_unlock(&ie->ie_lock);
625 it = ithread_create("intr: newborn", ih);
626 mtx_lock(&ie->ie_lock);
627 it->it_event = ie;
628 ih->ih_thread = it;
629 ithread_update(it); /* XXX - do we really need this?!?!? */
630 } else { /* Create the global per-event thread if we need one. */
631 while (ie->ie_thread == NULL && handler != NULL) {
632 if (ie->ie_flags & IE_ADDING_THREAD)
633 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
634 else {
635 ie->ie_flags |= IE_ADDING_THREAD;
636 mtx_unlock(&ie->ie_lock);
637 it = ithread_create("intr: newborn", ih);
638 mtx_lock(&ie->ie_lock);
639 ie->ie_flags &= ~IE_ADDING_THREAD;
640 ie->ie_thread = it;
641 it->it_event = ie;
642 ithread_update(it);
643 wakeup(ie);
644 }
645 }
646 }
647
648 /* Add the new handler to the event in priority order. */
649 TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
650 if (temp_ih->ih_pri > ih->ih_pri)
651 break;
652 }
653 if (temp_ih == NULL)
654 TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
655 else
656 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
657 intr_event_update(ie);
658
659 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
660 ie->ie_name);
661 mtx_unlock(&ie->ie_lock);
662
663 if (cookiep != NULL)
664 *cookiep = ih;
665 return (0);
666 }
667 #endif
668
669 /*
670 * Append a description preceded by a ':' to the name of the specified
671 * interrupt handler.
672 */
673 int
674 intr_event_describe_handler(struct intr_event *ie, void *cookie,
675 const char *descr)
676 {
677 struct intr_handler *ih;
678 size_t space;
679 char *start;
680
681 mtx_lock(&ie->ie_lock);
682 #ifdef INVARIANTS
683 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
684 if (ih == cookie)
685 break;
686 }
687 if (ih == NULL) {
688 mtx_unlock(&ie->ie_lock);
689 panic("handler %p not found in interrupt event %p", cookie, ie);
690 }
691 #endif
692 ih = cookie;
693
694 /*
695 * Look for an existing description by checking for an
696 * existing ":". This assumes device names do not include
697 * colons. If one is found, prepare to insert the new
698 * description at that point. If one is not found, find the
699 * end of the name to use as the insertion point.
700 */
701 start = strchr(ih->ih_name, ':');
702 if (start == NULL)
703 start = strchr(ih->ih_name, 0);
704
705 /*
706 * See if there is enough remaining room in the string for the
707 * description + ":". The "- 1" leaves room for the trailing
708 * '\0'. The "+ 1" accounts for the colon.
709 */
710 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
711 if (strlen(descr) + 1 > space) {
712 mtx_unlock(&ie->ie_lock);
713 return (ENOSPC);
714 }
715
716 /* Append a colon followed by the description. */
717 *start = ':';
718 strcpy(start + 1, descr);
719 intr_event_update(ie);
720 mtx_unlock(&ie->ie_lock);
721 return (0);
722 }
723
724 /*
725 * Return the ie_source field from the intr_event an intr_handler is
726 * associated with.
727 */
728 void *
729 intr_handler_source(void *cookie)
730 {
731 struct intr_handler *ih;
732 struct intr_event *ie;
733
734 ih = (struct intr_handler *)cookie;
735 if (ih == NULL)
736 return (NULL);
737 ie = ih->ih_event;
738 KASSERT(ie != NULL,
739 ("interrupt handler \"%s\" has a NULL interrupt event",
740 ih->ih_name));
741 return (ie->ie_source);
742 }
743
744 /*
745 * Sleep until an ithread finishes executing an interrupt handler.
746 *
747 * XXX Doesn't currently handle interrupt filters or fast interrupt
748 * handlers. This is intended for compatibility with linux drivers
749 * only. Do not use in BSD code.
750 */
751 void
752 _intr_drain(int irq)
753 {
754 struct intr_event *ie;
755 struct intr_thread *ithd;
756 struct thread *td;
757
758 ie = intr_lookup(irq);
759 if (ie == NULL)
760 return;
761 if (ie->ie_thread == NULL)
762 return;
763 ithd = ie->ie_thread;
764 td = ithd->it_thread;
765 /*
766 * We set the flag and wait for it to be cleared to avoid
767 * long delays with potentially busy interrupt handlers
768 * were we to only sample TD_AWAITING_INTR() every tick.
769 */
770 thread_lock(td);
771 if (!TD_AWAITING_INTR(td)) {
772 ithd->it_flags |= IT_WAIT;
773 while (ithd->it_flags & IT_WAIT) {
774 thread_unlock(td);
775 pause("idrain", 1);
776 thread_lock(td);
777 }
778 }
779 thread_unlock(td);
780 return;
781 }
782
783
784 #ifndef INTR_FILTER
785 int
786 intr_event_remove_handler(void *cookie)
787 {
788 struct intr_handler *handler = (struct intr_handler *)cookie;
789 struct intr_event *ie;
790 #ifdef INVARIANTS
791 struct intr_handler *ih;
792 #endif
793 #ifdef notyet
794 int dead;
795 #endif
796
797 if (handler == NULL)
798 return (EINVAL);
799 ie = handler->ih_event;
800 KASSERT(ie != NULL,
801 ("interrupt handler \"%s\" has a NULL interrupt event",
802 handler->ih_name));
803 mtx_lock(&ie->ie_lock);
804 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
805 ie->ie_name);
806 #ifdef INVARIANTS
807 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
808 if (ih == handler)
809 goto ok;
810 mtx_unlock(&ie->ie_lock);
811 panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
812 ih->ih_name, ie->ie_name);
813 ok:
814 #endif
815 /*
816 * If there is no ithread, then just remove the handler and return.
817 * XXX: Note that an INTR_FAST handler might be running on another
818 * CPU!
819 */
820 if (ie->ie_thread == NULL) {
821 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
822 mtx_unlock(&ie->ie_lock);
823 free(handler, M_ITHREAD);
824 return (0);
825 }
826
827 /*
828 * If the interrupt thread is already running, then just mark this
829 * handler as being dead and let the ithread do the actual removal.
830 *
831 * During a cold boot while cold is set, msleep() does not sleep,
832 * so we have to remove the handler here rather than letting the
833 * thread do it.
834 */
835 thread_lock(ie->ie_thread->it_thread);
836 if (!TD_AWAITING_INTR(ie->ie_thread->it_thread) && !cold) {
837 handler->ih_flags |= IH_DEAD;
838
839 /*
840 * Ensure that the thread will process the handler list
841 * again and remove this handler if it has already passed
842 * it on the list.
843 */
844 atomic_store_rel_int(&ie->ie_thread->it_need, 1);
845 } else
846 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
847 thread_unlock(ie->ie_thread->it_thread);
848 while (handler->ih_flags & IH_DEAD)
849 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
850 intr_event_update(ie);
851 #ifdef notyet
852 /*
853 * XXX: This could be bad in the case of ppbus(8). Also, I think
854 * this could lead to races of stale data when servicing an
855 * interrupt.
856 */
857 dead = 1;
858 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
859 if (!(ih->ih_flags & IH_FAST)) {
860 dead = 0;
861 break;
862 }
863 }
864 if (dead) {
865 ithread_destroy(ie->ie_thread);
866 ie->ie_thread = NULL;
867 }
868 #endif
869 mtx_unlock(&ie->ie_lock);
870 free(handler, M_ITHREAD);
871 return (0);
872 }
873
874 static int
875 intr_event_schedule_thread(struct intr_event *ie)
876 {
877 struct intr_entropy entropy;
878 struct intr_thread *it;
879 struct thread *td;
880 struct thread *ctd;
881 struct proc *p;
882
883 /*
884 * If no ithread or no handlers, then we have a stray interrupt.
885 */
886 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) ||
887 ie->ie_thread == NULL)
888 return (EINVAL);
889
890 ctd = curthread;
891 it = ie->ie_thread;
892 td = it->it_thread;
893 p = td->td_proc;
894
895 /*
896 * If any of the handlers for this ithread claim to be good
897 * sources of entropy, then gather some.
898 */
899 if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
900 CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
901 p->p_pid, td->td_name);
902 entropy.event = (uintptr_t)ie;
903 entropy.td = ctd;
904 random_harvest(&entropy, sizeof(entropy), 2,
905 RANDOM_INTERRUPT);
906 }
907
908 KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name));
909
910 /*
911 * Set it_need to tell the thread to keep running if it is already
912 * running. Then, lock the thread and see if we actually need to
913 * put it on the runqueue.
914 */
915 atomic_store_rel_int(&it->it_need, 1);
916 thread_lock(td);
917 if (TD_AWAITING_INTR(td)) {
918 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
919 td->td_name);
920 TD_CLR_IWAIT(td);
921 sched_add(td, SRQ_INTR);
922 } else {
923 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
924 __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
925 }
926 thread_unlock(td);
927
928 return (0);
929 }
930 #else
931 int
932 intr_event_remove_handler(void *cookie)
933 {
934 struct intr_handler *handler = (struct intr_handler *)cookie;
935 struct intr_event *ie;
936 struct intr_thread *it;
937 #ifdef INVARIANTS
938 struct intr_handler *ih;
939 #endif
940 #ifdef notyet
941 int dead;
942 #endif
943
944 if (handler == NULL)
945 return (EINVAL);
946 ie = handler->ih_event;
947 KASSERT(ie != NULL,
948 ("interrupt handler \"%s\" has a NULL interrupt event",
949 handler->ih_name));
950 mtx_lock(&ie->ie_lock);
951 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
952 ie->ie_name);
953 #ifdef INVARIANTS
954 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
955 if (ih == handler)
956 goto ok;
957 mtx_unlock(&ie->ie_lock);
958 panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
959 ih->ih_name, ie->ie_name);
960 ok:
961 #endif
962 /*
963 * If there are no ithreads (per event and per handler), then
964 * just remove the handler and return.
965 * XXX: Note that an INTR_FAST handler might be running on another CPU!
966 */
967 if (ie->ie_thread == NULL && handler->ih_thread == NULL) {
968 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
969 mtx_unlock(&ie->ie_lock);
970 free(handler, M_ITHREAD);
971 return (0);
972 }
973
974 /* Private or global ithread? */
975 it = (handler->ih_thread) ? handler->ih_thread : ie->ie_thread;
976 /*
977 * If the interrupt thread is already running, then just mark this
978 * handler as being dead and let the ithread do the actual removal.
979 *
980 * During a cold boot while cold is set, msleep() does not sleep,
981 * so we have to remove the handler here rather than letting the
982 * thread do it.
983 */
984 thread_lock(it->it_thread);
985 if (!TD_AWAITING_INTR(it->it_thread) && !cold) {
986 handler->ih_flags |= IH_DEAD;
987
988 /*
989 * Ensure that the thread will process the handler list
990 * again and remove this handler if it has already passed
991 * it on the list.
992 */
993 atomic_store_rel_int(&it->it_need, 1);
994 } else
995 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
996 thread_unlock(it->it_thread);
997 while (handler->ih_flags & IH_DEAD)
998 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
999 /*
1000 * At this point, the handler has been disconnected from the event,
1001 * so we can kill the private ithread if any.
1002 */
1003 if (handler->ih_thread) {
1004 ithread_destroy(handler->ih_thread);
1005 handler->ih_thread = NULL;
1006 }
1007 intr_event_update(ie);
1008 #ifdef notyet
1009 /*
1010 * XXX: This could be bad in the case of ppbus(8). Also, I think
1011 * this could lead to races of stale data when servicing an
1012 * interrupt.
1013 */
1014 dead = 1;
1015 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
1016 if (handler != NULL) {
1017 dead = 0;
1018 break;
1019 }
1020 }
1021 if (dead) {
1022 ithread_destroy(ie->ie_thread);
1023 ie->ie_thread = NULL;
1024 }
1025 #endif
1026 mtx_unlock(&ie->ie_lock);
1027 free(handler, M_ITHREAD);
1028 return (0);
1029 }
1030
1031 static int
1032 intr_event_schedule_thread(struct intr_event *ie, struct intr_thread *it)
1033 {
1034 struct intr_entropy entropy;
1035 struct thread *td;
1036 struct thread *ctd;
1037 struct proc *p;
1038
1039 /*
1040 * If no ithread or no handlers, then we have a stray interrupt.
1041 */
1042 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) || it == NULL)
1043 return (EINVAL);
1044
1045 ctd = curthread;
1046 td = it->it_thread;
1047 p = td->td_proc;
1048
1049 /*
1050 * If any of the handlers for this ithread claim to be good
1051 * sources of entropy, then gather some.
1052 */
1053 if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
1054 CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
1055 p->p_pid, td->td_name);
1056 entropy.event = (uintptr_t)ie;
1057 entropy.td = ctd;
1058 random_harvest(&entropy, sizeof(entropy), 2,
1059 RANDOM_INTERRUPT);
1060 }
1061
1062 KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name));
1063
1064 /*
1065 * Set it_need to tell the thread to keep running if it is already
1066 * running. Then, lock the thread and see if we actually need to
1067 * put it on the runqueue.
1068 */
1069 atomic_store_rel_int(&it->it_need, 1);
1070 thread_lock(td);
1071 if (TD_AWAITING_INTR(td)) {
1072 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
1073 td->td_name);
1074 TD_CLR_IWAIT(td);
1075 sched_add(td, SRQ_INTR);
1076 } else {
1077 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
1078 __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
1079 }
1080 thread_unlock(td);
1081
1082 return (0);
1083 }
1084 #endif
1085
1086 /*
1087 * Allow interrupt event binding for software interrupt handlers -- a no-op,
1088 * since interrupts are generated in software rather than being directed by
1089 * a PIC.
1090 */
1091 static int
1092 swi_assign_cpu(void *arg, u_char cpu)
1093 {
1094
1095 return (0);
1096 }
1097
1098 /*
1099 * Add a software interrupt handler to a specified event. If a given event
1100 * is not specified, then a new event is created.
1101 */
1102 int
1103 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
1104 void *arg, int pri, enum intr_type flags, void **cookiep)
1105 {
1106 struct intr_event *ie;
1107 int error;
1108
1109 if (flags & INTR_ENTROPY)
1110 return (EINVAL);
1111
1112 ie = (eventp != NULL) ? *eventp : NULL;
1113
1114 if (ie != NULL) {
1115 if (!(ie->ie_flags & IE_SOFT))
1116 return (EINVAL);
1117 } else {
1118 error = intr_event_create(&ie, NULL, IE_SOFT, 0,
1119 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
1120 if (error)
1121 return (error);
1122 if (eventp != NULL)
1123 *eventp = ie;
1124 }
1125 error = intr_event_add_handler(ie, name, NULL, handler, arg,
1126 PI_SWI(pri), flags, cookiep);
1127 return (error);
1128 }
1129
1130 /*
1131 * Schedule a software interrupt thread.
1132 */
1133 void
1134 swi_sched(void *cookie, int flags)
1135 {
1136 struct intr_handler *ih = (struct intr_handler *)cookie;
1137 struct intr_event *ie = ih->ih_event;
1138 struct intr_entropy entropy;
1139 int error;
1140
1141 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
1142 ih->ih_need);
1143
1144 if (harvest.swi) {
1145 CTR2(KTR_INTR, "swi_sched: pid %d (%s) gathering entropy",
1146 curproc->p_pid, curthread->td_name);
1147 entropy.event = (uintptr_t)ih;
1148 entropy.td = curthread;
1149 random_harvest(&entropy, sizeof(entropy), 1,
1150 RANDOM_SWI);
1151 }
1152
1153 /*
1154 * Set ih_need for this handler so that if the ithread is already
1155 * running it will execute this handler on the next pass. Otherwise,
1156 * it will execute it the next time it runs.
1157 */
1158 atomic_store_rel_int(&ih->ih_need, 1);
1159
1160 if (!(flags & SWI_DELAY)) {
1161 PCPU_INC(cnt.v_soft);
1162 #ifdef INTR_FILTER
1163 error = intr_event_schedule_thread(ie, ie->ie_thread);
1164 #else
1165 error = intr_event_schedule_thread(ie);
1166 #endif
1167 KASSERT(error == 0, ("stray software interrupt"));
1168 }
1169 }
1170
1171 /*
1172 * Remove a software interrupt handler. Currently this code does not
1173 * remove the associated interrupt event if it becomes empty. Calling code
1174 * may do so manually via intr_event_destroy(), but that's not really
1175 * an optimal interface.
1176 */
1177 int
1178 swi_remove(void *cookie)
1179 {
1180
1181 return (intr_event_remove_handler(cookie));
1182 }
1183
1184 #ifdef INTR_FILTER
1185 static void
1186 priv_ithread_execute_handler(struct proc *p, struct intr_handler *ih)
1187 {
1188 struct intr_event *ie;
1189
1190 ie = ih->ih_event;
1191 /*
1192 * If this handler is marked for death, remove it from
1193 * the list of handlers and wake up the sleeper.
1194 */
1195 if (ih->ih_flags & IH_DEAD) {
1196 mtx_lock(&ie->ie_lock);
1197 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
1198 ih->ih_flags &= ~IH_DEAD;
1199 wakeup(ih);
1200 mtx_unlock(&ie->ie_lock);
1201 return;
1202 }
1203
1204 /* Execute this handler. */
1205 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1206 __func__, p->p_pid, (void *)ih->ih_handler, ih->ih_argument,
1207 ih->ih_name, ih->ih_flags);
1208
1209 if (!(ih->ih_flags & IH_MPSAFE))
1210 mtx_lock(&Giant);
1211 ih->ih_handler(ih->ih_argument);
1212 if (!(ih->ih_flags & IH_MPSAFE))
1213 mtx_unlock(&Giant);
1214 }
1215 #endif
1216
1217 /*
1218 * This is a public function for use by drivers that mux interrupt
1219 * handlers for child devices from their interrupt handler.
1220 */
1221 void
1222 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
1223 {
1224 struct intr_handler *ih, *ihn;
1225
1226 TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
1227 /*
1228 * If this handler is marked for death, remove it from
1229 * the list of handlers and wake up the sleeper.
1230 */
1231 if (ih->ih_flags & IH_DEAD) {
1232 mtx_lock(&ie->ie_lock);
1233 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
1234 ih->ih_flags &= ~IH_DEAD;
1235 wakeup(ih);
1236 mtx_unlock(&ie->ie_lock);
1237 continue;
1238 }
1239
1240 /* Skip filter only handlers */
1241 if (ih->ih_handler == NULL)
1242 continue;
1243
1244 /*
1245 * For software interrupt threads, we only execute
1246 * handlers that have their need flag set. Hardware
1247 * interrupt threads always invoke all of their handlers.
1248 */
1249 if (ie->ie_flags & IE_SOFT) {
1250 if (atomic_load_acq_int(&ih->ih_need) == 0)
1251 continue;
1252 else
1253 atomic_store_rel_int(&ih->ih_need, 0);
1254 }
1255
1256 /* Execute this handler. */
1257 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1258 __func__, p->p_pid, (void *)ih->ih_handler,
1259 ih->ih_argument, ih->ih_name, ih->ih_flags);
1260
1261 if (!(ih->ih_flags & IH_MPSAFE))
1262 mtx_lock(&Giant);
1263 ih->ih_handler(ih->ih_argument);
1264 if (!(ih->ih_flags & IH_MPSAFE))
1265 mtx_unlock(&Giant);
1266 }
1267 }
1268
1269 static void
1270 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1271 {
1272
1273 /* Interrupt handlers should not sleep. */
1274 if (!(ie->ie_flags & IE_SOFT))
1275 THREAD_NO_SLEEPING();
1276 intr_event_execute_handlers(p, ie);
1277 if (!(ie->ie_flags & IE_SOFT))
1278 THREAD_SLEEPING_OK();
1279
1280 /*
1281 * Interrupt storm handling:
1282 *
1283 * If this interrupt source is currently storming, then throttle
1284 * it to only fire the handler once per clock tick.
1285 *
1286 * If this interrupt source is not currently storming, but the
1287 * number of back to back interrupts exceeds the storm threshold,
1288 * then enter storming mode.
1289 */
1290 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
1291 !(ie->ie_flags & IE_SOFT)) {
1292 /* Report the message only once every second. */
1293 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1294 printf(
1295 "interrupt storm detected on \"%s\"; throttling interrupt source\n",
1296 ie->ie_name);
1297 }
1298 pause("istorm", 1);
1299 } else
1300 ie->ie_count++;
1301
1302 /*
1303 * Now that all the handlers have had a chance to run, reenable
1304 * the interrupt source.
1305 */
1306 if (ie->ie_post_ithread != NULL)
1307 ie->ie_post_ithread(ie->ie_source);
1308 }
1309
1310 #ifndef INTR_FILTER
1311 /*
1312 * This is the main code for interrupt threads.
1313 */
1314 static void
1315 ithread_loop(void *arg)
1316 {
1317 struct intr_thread *ithd;
1318 struct intr_event *ie;
1319 struct thread *td;
1320 struct proc *p;
1321 int wake;
1322
1323 td = curthread;
1324 p = td->td_proc;
1325 ithd = (struct intr_thread *)arg;
1326 KASSERT(ithd->it_thread == td,
1327 ("%s: ithread and proc linkage out of sync", __func__));
1328 ie = ithd->it_event;
1329 ie->ie_count = 0;
1330 wake = 0;
1331
1332 /*
1333 * As long as we have interrupts outstanding, go through the
1334 * list of handlers, giving each one a go at it.
1335 */
1336 for (;;) {
1337 /*
1338 * If we are an orphaned thread, then just die.
1339 */
1340 if (ithd->it_flags & IT_DEAD) {
1341 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1342 p->p_pid, td->td_name);
1343 free(ithd, M_ITHREAD);
1344 kthread_exit();
1345 }
1346
1347 /*
1348 * Service interrupts. If another interrupt arrives while
1349 * we are running, it will set it_need to note that we
1350 * should make another pass.
1351 */
1352 while (atomic_load_acq_int(&ithd->it_need) != 0) {
1353 /*
1354 * This might need a full read and write barrier
1355 * to make sure that this write posts before any
1356 * of the memory or device accesses in the
1357 * handlers.
1358 */
1359 atomic_store_rel_int(&ithd->it_need, 0);
1360 ithread_execute_handlers(p, ie);
1361 }
1362 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1363 mtx_assert(&Giant, MA_NOTOWNED);
1364
1365 /*
1366 * Processed all our interrupts. Now get the sched
1367 * lock. This may take a while and it_need may get
1368 * set again, so we have to check it again.
1369 */
1370 thread_lock(td);
1371 if ((atomic_load_acq_int(&ithd->it_need) == 0) &&
1372 !(ithd->it_flags & (IT_DEAD | IT_WAIT))) {
1373 TD_SET_IWAIT(td);
1374 ie->ie_count = 0;
1375 mi_switch(SW_VOL | SWT_IWAIT, NULL);
1376 }
1377 if (ithd->it_flags & IT_WAIT) {
1378 wake = 1;
1379 ithd->it_flags &= ~IT_WAIT;
1380 }
1381 thread_unlock(td);
1382 if (wake) {
1383 wakeup(ithd);
1384 wake = 0;
1385 }
1386 }
1387 }
1388
1389 /*
1390 * Main interrupt handling body.
1391 *
1392 * Input:
1393 * o ie: the event connected to this interrupt.
1394 * o frame: some archs (i.e. i386) pass a frame to some.
1395 * handlers as their main argument.
1396 * Return value:
1397 * o 0: everything ok.
1398 * o EINVAL: stray interrupt.
1399 */
1400 int
1401 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1402 {
1403 struct intr_handler *ih;
1404 struct trapframe *oldframe;
1405 struct thread *td;
1406 int error, ret, thread;
1407
1408 td = curthread;
1409
1410 /* An interrupt with no event or handlers is a stray interrupt. */
1411 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
1412 return (EINVAL);
1413
1414 /*
1415 * Execute fast interrupt handlers directly.
1416 * To support clock handlers, if a handler registers
1417 * with a NULL argument, then we pass it a pointer to
1418 * a trapframe as its argument.
1419 */
1420 td->td_intr_nesting_level++;
1421 thread = 0;
1422 ret = 0;
1423 critical_enter();
1424 oldframe = td->td_intr_frame;
1425 td->td_intr_frame = frame;
1426 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
1427 if (ih->ih_filter == NULL) {
1428 thread = 1;
1429 continue;
1430 }
1431 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1432 ih->ih_filter, ih->ih_argument == NULL ? frame :
1433 ih->ih_argument, ih->ih_name);
1434 if (ih->ih_argument == NULL)
1435 ret = ih->ih_filter(frame);
1436 else
1437 ret = ih->ih_filter(ih->ih_argument);
1438 KASSERT(ret == FILTER_STRAY ||
1439 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1440 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1441 ("%s: incorrect return value %#x from %s", __func__, ret,
1442 ih->ih_name));
1443
1444 /*
1445 * Wrapper handler special handling:
1446 *
1447 * in some particular cases (like pccard and pccbb),
1448 * the _real_ device handler is wrapped in a couple of
1449 * functions - a filter wrapper and an ithread wrapper.
1450 * In this case (and just in this case), the filter wrapper
1451 * could ask the system to schedule the ithread and mask
1452 * the interrupt source if the wrapped handler is composed
1453 * of just an ithread handler.
1454 *
1455 * TODO: write a generic wrapper to avoid people rolling
1456 * their own
1457 */
1458 if (!thread) {
1459 if (ret == FILTER_SCHEDULE_THREAD)
1460 thread = 1;
1461 }
1462 }
1463 td->td_intr_frame = oldframe;
1464
1465 if (thread) {
1466 if (ie->ie_pre_ithread != NULL)
1467 ie->ie_pre_ithread(ie->ie_source);
1468 } else {
1469 if (ie->ie_post_filter != NULL)
1470 ie->ie_post_filter(ie->ie_source);
1471 }
1472
1473 /* Schedule the ithread if needed. */
1474 if (thread) {
1475 error = intr_event_schedule_thread(ie);
1476 #ifndef XEN
1477 KASSERT(error == 0, ("bad stray interrupt"));
1478 #else
1479 if (error != 0)
1480 log(LOG_WARNING, "bad stray interrupt");
1481 #endif
1482 }
1483 critical_exit();
1484 td->td_intr_nesting_level--;
1485 return (0);
1486 }
1487 #else
1488 /*
1489 * This is the main code for interrupt threads.
1490 */
1491 static void
1492 ithread_loop(void *arg)
1493 {
1494 struct intr_thread *ithd;
1495 struct intr_handler *ih;
1496 struct intr_event *ie;
1497 struct thread *td;
1498 struct proc *p;
1499 int priv;
1500 int wake;
1501
1502 td = curthread;
1503 p = td->td_proc;
1504 ih = (struct intr_handler *)arg;
1505 priv = (ih->ih_thread != NULL) ? 1 : 0;
1506 ithd = (priv) ? ih->ih_thread : ih->ih_event->ie_thread;
1507 KASSERT(ithd->it_thread == td,
1508 ("%s: ithread and proc linkage out of sync", __func__));
1509 ie = ithd->it_event;
1510 ie->ie_count = 0;
1511 wake = 0;
1512
1513 /*
1514 * As long as we have interrupts outstanding, go through the
1515 * list of handlers, giving each one a go at it.
1516 */
1517 for (;;) {
1518 /*
1519 * If we are an orphaned thread, then just die.
1520 */
1521 if (ithd->it_flags & IT_DEAD) {
1522 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1523 p->p_pid, td->td_name);
1524 free(ithd, M_ITHREAD);
1525 kthread_exit();
1526 }
1527
1528 /*
1529 * Service interrupts. If another interrupt arrives while
1530 * we are running, it will set it_need to note that we
1531 * should make another pass.
1532 */
1533 while (atomic_load_acq_int(&ithd->it_need) != 0) {
1534 /*
1535 * This might need a full read and write barrier
1536 * to make sure that this write posts before any
1537 * of the memory or device accesses in the
1538 * handlers.
1539 */
1540 atomic_store_rel_int(&ithd->it_need, 0);
1541 if (priv)
1542 priv_ithread_execute_handler(p, ih);
1543 else
1544 ithread_execute_handlers(p, ie);
1545 }
1546 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1547 mtx_assert(&Giant, MA_NOTOWNED);
1548
1549 /*
1550 * Processed all our interrupts. Now get the sched
1551 * lock. This may take a while and it_need may get
1552 * set again, so we have to check it again.
1553 */
1554 thread_lock(td);
1555 if ((atomic_load_acq_int(&ithd->it_need) == 0) &&
1556 !(ithd->it_flags & (IT_DEAD | IT_WAIT))) {
1557 TD_SET_IWAIT(td);
1558 ie->ie_count = 0;
1559 mi_switch(SW_VOL | SWT_IWAIT, NULL);
1560 }
1561 if (ithd->it_flags & IT_WAIT) {
1562 wake = 1;
1563 ithd->it_flags &= ~IT_WAIT;
1564 }
1565 thread_unlock(td);
1566 if (wake) {
1567 wakeup(ithd);
1568 wake = 0;
1569 }
1570 }
1571 }
1572
1573 /*
1574 * Main loop for interrupt filter.
1575 *
1576 * Some architectures (i386, amd64 and arm) require the optional frame
1577 * parameter, and use it as the main argument for fast handler execution
1578 * when ih_argument == NULL.
1579 *
1580 * Return value:
1581 * o FILTER_STRAY: No filter recognized the event, and no
1582 * filter-less handler is registered on this
1583 * line.
1584 * o FILTER_HANDLED: A filter claimed the event and served it.
1585 * o FILTER_SCHEDULE_THREAD: No filter claimed the event, but there's at
1586 * least one filter-less handler on this line.
1587 * o FILTER_HANDLED |
1588 * FILTER_SCHEDULE_THREAD: A filter claimed the event, and asked for
1589 * scheduling the per-handler ithread.
1590 *
1591 * In case an ithread has to be scheduled, in *ithd there will be a
1592 * pointer to a struct intr_thread containing the thread to be
1593 * scheduled.
1594 */
1595
1596 static int
1597 intr_filter_loop(struct intr_event *ie, struct trapframe *frame,
1598 struct intr_thread **ithd)
1599 {
1600 struct intr_handler *ih;
1601 void *arg;
1602 int ret, thread_only;
1603
1604 ret = 0;
1605 thread_only = 0;
1606 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
1607 /*
1608 * Execute fast interrupt handlers directly.
1609 * To support clock handlers, if a handler registers
1610 * with a NULL argument, then we pass it a pointer to
1611 * a trapframe as its argument.
1612 */
1613 arg = ((ih->ih_argument == NULL) ? frame : ih->ih_argument);
1614
1615 CTR5(KTR_INTR, "%s: exec %p/%p(%p) for %s", __func__,
1616 ih->ih_filter, ih->ih_handler, arg, ih->ih_name);
1617
1618 if (ih->ih_filter != NULL)
1619 ret = ih->ih_filter(arg);
1620 else {
1621 thread_only = 1;
1622 continue;
1623 }
1624 KASSERT(ret == FILTER_STRAY ||
1625 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1626 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1627 ("%s: incorrect return value %#x from %s", __func__, ret,
1628 ih->ih_name));
1629 if (ret & FILTER_STRAY)
1630 continue;
1631 else {
1632 *ithd = ih->ih_thread;
1633 return (ret);
1634 }
1635 }
1636
1637 /*
1638 * No filters handled the interrupt and we have at least
1639 * one handler without a filter. In this case, we schedule
1640 * all of the filter-less handlers to run in the ithread.
1641 */
1642 if (thread_only) {
1643 *ithd = ie->ie_thread;
1644 return (FILTER_SCHEDULE_THREAD);
1645 }
1646 return (FILTER_STRAY);
1647 }
1648
1649 /*
1650 * Main interrupt handling body.
1651 *
1652 * Input:
1653 * o ie: the event connected to this interrupt.
1654 * o frame: some archs (i.e. i386) pass a frame to some.
1655 * handlers as their main argument.
1656 * Return value:
1657 * o 0: everything ok.
1658 * o EINVAL: stray interrupt.
1659 */
1660 int
1661 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1662 {
1663 struct intr_thread *ithd;
1664 struct trapframe *oldframe;
1665 struct thread *td;
1666 int thread;
1667
1668 ithd = NULL;
1669 td = curthread;
1670
1671 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
1672 return (EINVAL);
1673
1674 td->td_intr_nesting_level++;
1675 thread = 0;
1676 critical_enter();
1677 oldframe = td->td_intr_frame;
1678 td->td_intr_frame = frame;
1679 thread = intr_filter_loop(ie, frame, &ithd);
1680 if (thread & FILTER_HANDLED) {
1681 if (ie->ie_post_filter != NULL)
1682 ie->ie_post_filter(ie->ie_source);
1683 } else {
1684 if (ie->ie_pre_ithread != NULL)
1685 ie->ie_pre_ithread(ie->ie_source);
1686 }
1687 td->td_intr_frame = oldframe;
1688 critical_exit();
1689
1690 /* Interrupt storm logic */
1691 if (thread & FILTER_STRAY) {
1692 ie->ie_count++;
1693 if (ie->ie_count < intr_storm_threshold)
1694 printf("Interrupt stray detection not present\n");
1695 }
1696
1697 /* Schedule an ithread if needed. */
1698 if (thread & FILTER_SCHEDULE_THREAD) {
1699 if (intr_event_schedule_thread(ie, ithd) != 0)
1700 panic("%s: impossible stray interrupt", __func__);
1701 }
1702 td->td_intr_nesting_level--;
1703 return (0);
1704 }
1705 #endif
1706
1707 #ifdef DDB
1708 /*
1709 * Dump details about an interrupt handler
1710 */
1711 static void
1712 db_dump_intrhand(struct intr_handler *ih)
1713 {
1714 int comma;
1715
1716 db_printf("\t%-10s ", ih->ih_name);
1717 switch (ih->ih_pri) {
1718 case PI_REALTIME:
1719 db_printf("CLK ");
1720 break;
1721 case PI_AV:
1722 db_printf("AV ");
1723 break;
1724 case PI_TTY:
1725 db_printf("TTY ");
1726 break;
1727 case PI_NET:
1728 db_printf("NET ");
1729 break;
1730 case PI_DISK:
1731 db_printf("DISK");
1732 break;
1733 case PI_DULL:
1734 db_printf("DULL");
1735 break;
1736 default:
1737 if (ih->ih_pri >= PI_SOFT)
1738 db_printf("SWI ");
1739 else
1740 db_printf("%4u", ih->ih_pri);
1741 break;
1742 }
1743 db_printf(" ");
1744 if (ih->ih_filter != NULL) {
1745 db_printf("[F]");
1746 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1747 }
1748 if (ih->ih_handler != NULL) {
1749 if (ih->ih_filter != NULL)
1750 db_printf(",");
1751 db_printf("[H]");
1752 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1753 }
1754 db_printf("(%p)", ih->ih_argument);
1755 if (ih->ih_need ||
1756 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1757 IH_MPSAFE)) != 0) {
1758 db_printf(" {");
1759 comma = 0;
1760 if (ih->ih_flags & IH_EXCLUSIVE) {
1761 if (comma)
1762 db_printf(", ");
1763 db_printf("EXCL");
1764 comma = 1;
1765 }
1766 if (ih->ih_flags & IH_ENTROPY) {
1767 if (comma)
1768 db_printf(", ");
1769 db_printf("ENTROPY");
1770 comma = 1;
1771 }
1772 if (ih->ih_flags & IH_DEAD) {
1773 if (comma)
1774 db_printf(", ");
1775 db_printf("DEAD");
1776 comma = 1;
1777 }
1778 if (ih->ih_flags & IH_MPSAFE) {
1779 if (comma)
1780 db_printf(", ");
1781 db_printf("MPSAFE");
1782 comma = 1;
1783 }
1784 if (ih->ih_need) {
1785 if (comma)
1786 db_printf(", ");
1787 db_printf("NEED");
1788 }
1789 db_printf("}");
1790 }
1791 db_printf("\n");
1792 }
1793
1794 /*
1795 * Dump details about a event.
1796 */
1797 void
1798 db_dump_intr_event(struct intr_event *ie, int handlers)
1799 {
1800 struct intr_handler *ih;
1801 struct intr_thread *it;
1802 int comma;
1803
1804 db_printf("%s ", ie->ie_fullname);
1805 it = ie->ie_thread;
1806 if (it != NULL)
1807 db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1808 else
1809 db_printf("(no thread)");
1810 if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 ||
1811 (it != NULL && it->it_need)) {
1812 db_printf(" {");
1813 comma = 0;
1814 if (ie->ie_flags & IE_SOFT) {
1815 db_printf("SOFT");
1816 comma = 1;
1817 }
1818 if (ie->ie_flags & IE_ENTROPY) {
1819 if (comma)
1820 db_printf(", ");
1821 db_printf("ENTROPY");
1822 comma = 1;
1823 }
1824 if (ie->ie_flags & IE_ADDING_THREAD) {
1825 if (comma)
1826 db_printf(", ");
1827 db_printf("ADDING_THREAD");
1828 comma = 1;
1829 }
1830 if (it != NULL && it->it_need) {
1831 if (comma)
1832 db_printf(", ");
1833 db_printf("NEED");
1834 }
1835 db_printf("}");
1836 }
1837 db_printf("\n");
1838
1839 if (handlers)
1840 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
1841 db_dump_intrhand(ih);
1842 }
1843
1844 /*
1845 * Dump data about interrupt handlers
1846 */
1847 DB_SHOW_COMMAND(intr, db_show_intr)
1848 {
1849 struct intr_event *ie;
1850 int all, verbose;
1851
1852 verbose = strchr(modif, 'v') != NULL;
1853 all = strchr(modif, 'a') != NULL;
1854 TAILQ_FOREACH(ie, &event_list, ie_list) {
1855 if (!all && TAILQ_EMPTY(&ie->ie_handlers))
1856 continue;
1857 db_dump_intr_event(ie, verbose);
1858 if (db_pager_quit)
1859 break;
1860 }
1861 }
1862 #endif /* DDB */
1863
1864 /*
1865 * Start standard software interrupt threads
1866 */
1867 static void
1868 start_softintr(void *dummy)
1869 {
1870
1871 if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
1872 panic("died while creating vm swi ithread");
1873 }
1874 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1875 NULL);
1876
1877 /*
1878 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1879 * The data for this machine dependent, and the declarations are in machine
1880 * dependent code. The layout of intrnames and intrcnt however is machine
1881 * independent.
1882 *
1883 * We do not know the length of intrcnt and intrnames at compile time, so
1884 * calculate things at run time.
1885 */
1886 static int
1887 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1888 {
1889 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1890 }
1891
1892 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1893 NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1894
1895 static int
1896 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1897 {
1898 #ifdef SCTL_MASK32
1899 uint32_t *intrcnt32;
1900 unsigned i;
1901 int error;
1902
1903 if (req->flags & SCTL_MASK32) {
1904 if (!req->oldptr)
1905 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1906 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1907 if (intrcnt32 == NULL)
1908 return (ENOMEM);
1909 for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1910 intrcnt32[i] = intrcnt[i];
1911 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1912 free(intrcnt32, M_TEMP);
1913 return (error);
1914 }
1915 #endif
1916 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1917 }
1918
1919 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1920 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");
1921
1922 #ifdef DDB
1923 /*
1924 * DDB command to dump the interrupt statistics.
1925 */
1926 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
1927 {
1928 u_long *i;
1929 char *cp;
1930 u_int j;
1931
1932 cp = intrnames;
1933 j = 0;
1934 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1935 i++, j++) {
1936 if (*cp == '\0')
1937 break;
1938 if (*i != 0)
1939 db_printf("%s\t%lu\n", cp, *i);
1940 cp += strlen(cp) + 1;
1941 }
1942 }
1943 #endif
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