1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include "opt_ddb.h"
31 #include "opt_hwpmc_hooks.h"
32 #include "opt_kstack_usage_prof.h"
33
34 #include <sys/param.h>
35 #include <sys/bus.h>
36 #include <sys/conf.h>
37 #include <sys/cpuset.h>
38 #include <sys/rtprio.h>
39 #include <sys/systm.h>
40 #include <sys/interrupt.h>
41 #include <sys/kernel.h>
42 #include <sys/kthread.h>
43 #include <sys/ktr.h>
44 #include <sys/limits.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mutex.h>
48 #include <sys/priv.h>
49 #include <sys/proc.h>
50 #include <sys/epoch.h>
51 #include <sys/random.h>
52 #include <sys/resourcevar.h>
53 #include <sys/sched.h>
54 #include <sys/smp.h>
55 #include <sys/sysctl.h>
56 #include <sys/syslog.h>
57 #include <sys/unistd.h>
58 #include <sys/vmmeter.h>
59 #include <machine/atomic.h>
60 #include <machine/cpu.h>
61 #include <machine/md_var.h>
62 #include <machine/smp.h>
63 #include <machine/stdarg.h>
64 #ifdef DDB
65 #include <ddb/ddb.h>
66 #include <ddb/db_sym.h>
67 #endif
68
69 /*
70 * Describe an interrupt thread. There is one of these per interrupt event.
71 */
72 struct intr_thread {
73 struct intr_event *it_event;
74 struct thread *it_thread; /* Kernel thread. */
75 int it_flags; /* (j) IT_* flags. */
76 int it_need; /* Needs service. */
77 int it_waiting; /* Waiting in the runq. */
78 };
79
80 /* Interrupt thread flags kept in it_flags */
81 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */
82 #define IT_WAIT 0x000002 /* Thread is waiting for completion. */
83
84 struct intr_entropy {
85 struct thread *td;
86 uintptr_t event;
87 };
88
89 struct intr_event *clk_intr_event;
90 struct proc *intrproc;
91
92 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
93
94 static int intr_storm_threshold = 0;
95 SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RWTUN,
96 &intr_storm_threshold, 0,
97 "Number of consecutive interrupts before storm protection is enabled");
98 static int intr_epoch_batch = 1000;
99 SYSCTL_INT(_hw, OID_AUTO, intr_epoch_batch, CTLFLAG_RWTUN, &intr_epoch_batch,
100 0, "Maximum interrupt handler executions without re-entering epoch(9)");
101 #ifdef HWPMC_HOOKS
102 static int intr_hwpmc_waiting_report_threshold = 1;
103 SYSCTL_INT(_hw, OID_AUTO, intr_hwpmc_waiting_report_threshold, CTLFLAG_RWTUN,
104 &intr_hwpmc_waiting_report_threshold, 1,
105 "Threshold for reporting number of events in a workq");
106 #define PMC_HOOK_INSTALLED_ANY() __predict_false(pmc_hook != NULL)
107 #endif
108 static TAILQ_HEAD(, intr_event) event_list =
109 TAILQ_HEAD_INITIALIZER(event_list);
110 static struct mtx event_lock;
111 MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF);
112
113 static void intr_event_update(struct intr_event *ie);
114 static int intr_event_schedule_thread(struct intr_event *ie, struct trapframe *frame);
115 static struct intr_thread *ithread_create(const char *name);
116 static void ithread_destroy(struct intr_thread *ithread);
117 static void ithread_execute_handlers(struct proc *p,
118 struct intr_event *ie);
119 static void ithread_loop(void *);
120 static void ithread_update(struct intr_thread *ithd);
121 static void start_softintr(void *);
122
123 #ifdef HWPMC_HOOKS
124 #include <sys/pmckern.h>
125 PMC_SOFT_DEFINE( , , intr, all);
126 PMC_SOFT_DEFINE( , , intr, ithread);
127 PMC_SOFT_DEFINE( , , intr, filter);
128 PMC_SOFT_DEFINE( , , intr, stray);
129 PMC_SOFT_DEFINE( , , intr, schedule);
130 PMC_SOFT_DEFINE( , , intr, waiting);
131
132 #define PMC_SOFT_CALL_INTR_HLPR(event, frame) \
133 do { \
134 if (frame != NULL) \
135 PMC_SOFT_CALL_TF( , , intr, event, frame); \
136 else \
137 PMC_SOFT_CALL( , , intr, event); \
138 } while (0)
139 #endif
140
141 /* Map an interrupt type to an ithread priority. */
142 u_char
intr_priority(enum intr_type flags)143 intr_priority(enum intr_type flags)
144 {
145 u_char pri;
146
147 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
148 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
149 switch (flags) {
150 case INTR_TYPE_TTY:
151 pri = PI_TTY;
152 break;
153 case INTR_TYPE_BIO:
154 pri = PI_DISK;
155 break;
156 case INTR_TYPE_NET:
157 pri = PI_NET;
158 break;
159 case INTR_TYPE_CAM:
160 pri = PI_DISK;
161 break;
162 case INTR_TYPE_AV:
163 pri = PI_AV;
164 break;
165 case INTR_TYPE_CLK:
166 pri = PI_REALTIME;
167 break;
168 case INTR_TYPE_MISC:
169 pri = PI_DULL; /* don't care */
170 break;
171 default:
172 /* We didn't specify an interrupt level. */
173 panic("intr_priority: no interrupt type in flags");
174 }
175
176 return pri;
177 }
178
179 /*
180 * Update an ithread based on the associated intr_event.
181 */
182 static void
ithread_update(struct intr_thread * ithd)183 ithread_update(struct intr_thread *ithd)
184 {
185 struct intr_event *ie;
186 struct thread *td;
187 u_char pri;
188
189 ie = ithd->it_event;
190 td = ithd->it_thread;
191 mtx_assert(&ie->ie_lock, MA_OWNED);
192
193 /* Determine the overall priority of this event. */
194 if (CK_SLIST_EMPTY(&ie->ie_handlers))
195 pri = PRI_MAX_ITHD;
196 else
197 pri = CK_SLIST_FIRST(&ie->ie_handlers)->ih_pri;
198
199 /* Update name and priority. */
200 strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
201 #ifdef KTR
202 sched_clear_tdname(td);
203 #endif
204 thread_lock(td);
205 sched_ithread_prio(td, pri);
206 thread_unlock(td);
207 }
208
209 /*
210 * Regenerate the full name of an interrupt event and update its priority.
211 */
212 static void
intr_event_update(struct intr_event * ie)213 intr_event_update(struct intr_event *ie)
214 {
215 struct intr_handler *ih;
216 char *last;
217 int missed, space, flags;
218
219 /* Start off with no entropy and just the name of the event. */
220 mtx_assert(&ie->ie_lock, MA_OWNED);
221 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
222 flags = 0;
223 missed = 0;
224 space = 1;
225
226 /* Run through all the handlers updating values. */
227 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
228 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
229 sizeof(ie->ie_fullname)) {
230 strcat(ie->ie_fullname, " ");
231 strcat(ie->ie_fullname, ih->ih_name);
232 space = 0;
233 } else
234 missed++;
235 flags |= ih->ih_flags;
236 }
237 ie->ie_hflags = flags;
238
239 /*
240 * If there is only one handler and its name is too long, just copy in
241 * as much of the end of the name (includes the unit number) as will
242 * fit. Otherwise, we have multiple handlers and not all of the names
243 * will fit. Add +'s to indicate missing names. If we run out of room
244 * and still have +'s to add, change the last character from a + to a *.
245 */
246 if (missed == 1 && space == 1) {
247 ih = CK_SLIST_FIRST(&ie->ie_handlers);
248 missed = strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 -
249 sizeof(ie->ie_fullname);
250 strcat(ie->ie_fullname, (missed == 0) ? " " : "-");
251 strcat(ie->ie_fullname, &ih->ih_name[missed]);
252 missed = 0;
253 }
254 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
255 while (missed-- > 0) {
256 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
257 if (*last == '+') {
258 *last = '*';
259 break;
260 } else
261 *last = '+';
262 } else if (space) {
263 strcat(ie->ie_fullname, " +");
264 space = 0;
265 } else
266 strcat(ie->ie_fullname, "+");
267 }
268
269 /*
270 * If this event has an ithread, update it's priority and
271 * name.
272 */
273 if (ie->ie_thread != NULL)
274 ithread_update(ie->ie_thread);
275 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
276 }
277
278 int
intr_event_create(struct intr_event ** event,void * source,int flags,int irq,void (* pre_ithread)(void *),void (* post_ithread)(void *),void (* post_filter)(void *),int (* assign_cpu)(void *,int),const char * fmt,...)279 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
280 void (*pre_ithread)(void *), void (*post_ithread)(void *),
281 void (*post_filter)(void *), int (*assign_cpu)(void *, int),
282 const char *fmt, ...)
283 {
284 struct intr_event *ie;
285 va_list ap;
286
287 /* The only valid flag during creation is IE_SOFT. */
288 if ((flags & ~IE_SOFT) != 0)
289 return (EINVAL);
290 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
291 ie->ie_source = source;
292 ie->ie_pre_ithread = pre_ithread;
293 ie->ie_post_ithread = post_ithread;
294 ie->ie_post_filter = post_filter;
295 ie->ie_assign_cpu = assign_cpu;
296 ie->ie_flags = flags;
297 ie->ie_irq = irq;
298 ie->ie_cpu = NOCPU;
299 CK_SLIST_INIT(&ie->ie_handlers);
300 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
301
302 va_start(ap, fmt);
303 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
304 va_end(ap);
305 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
306 mtx_lock(&event_lock);
307 TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
308 mtx_unlock(&event_lock);
309 if (event != NULL)
310 *event = ie;
311 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
312 return (0);
313 }
314
315 /*
316 * Bind an interrupt event to the specified CPU. Note that not all
317 * platforms support binding an interrupt to a CPU. For those
318 * platforms this request will fail. Using a cpu id of NOCPU unbinds
319 * the interrupt event.
320 */
321 static int
_intr_event_bind(struct intr_event * ie,int cpu,bool bindirq,bool bindithread)322 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread)
323 {
324 lwpid_t id;
325 int error;
326
327 /* Need a CPU to bind to. */
328 if (cpu != NOCPU && CPU_ABSENT(cpu))
329 return (EINVAL);
330
331 if (ie->ie_assign_cpu == NULL)
332 return (EOPNOTSUPP);
333
334 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
335 if (error)
336 return (error);
337
338 /*
339 * If we have any ithreads try to set their mask first to verify
340 * permissions, etc.
341 */
342 if (bindithread) {
343 mtx_lock(&ie->ie_lock);
344 if (ie->ie_thread != NULL) {
345 id = ie->ie_thread->it_thread->td_tid;
346 mtx_unlock(&ie->ie_lock);
347 error = cpuset_setithread(id, cpu);
348 if (error)
349 return (error);
350 } else
351 mtx_unlock(&ie->ie_lock);
352 }
353 if (bindirq)
354 error = ie->ie_assign_cpu(ie->ie_source, cpu);
355 if (error) {
356 if (bindithread) {
357 mtx_lock(&ie->ie_lock);
358 if (ie->ie_thread != NULL) {
359 cpu = ie->ie_cpu;
360 id = ie->ie_thread->it_thread->td_tid;
361 mtx_unlock(&ie->ie_lock);
362 (void)cpuset_setithread(id, cpu);
363 } else
364 mtx_unlock(&ie->ie_lock);
365 }
366 return (error);
367 }
368
369 if (bindirq) {
370 mtx_lock(&ie->ie_lock);
371 ie->ie_cpu = cpu;
372 mtx_unlock(&ie->ie_lock);
373 }
374
375 return (error);
376 }
377
378 /*
379 * Bind an interrupt event to the specified CPU. For supported platforms, any
380 * associated ithreads as well as the primary interrupt context will be bound
381 * to the specificed CPU.
382 */
383 int
intr_event_bind(struct intr_event * ie,int cpu)384 intr_event_bind(struct intr_event *ie, int cpu)
385 {
386
387 return (_intr_event_bind(ie, cpu, true, true));
388 }
389
390 /*
391 * Bind an interrupt event to the specified CPU, but do not bind associated
392 * ithreads.
393 */
394 int
intr_event_bind_irqonly(struct intr_event * ie,int cpu)395 intr_event_bind_irqonly(struct intr_event *ie, int cpu)
396 {
397
398 return (_intr_event_bind(ie, cpu, true, false));
399 }
400
401 /*
402 * Bind an interrupt event's ithread to the specified CPU.
403 */
404 int
intr_event_bind_ithread(struct intr_event * ie,int cpu)405 intr_event_bind_ithread(struct intr_event *ie, int cpu)
406 {
407
408 return (_intr_event_bind(ie, cpu, false, true));
409 }
410
411 /*
412 * Bind an interrupt event's ithread to the specified cpuset.
413 */
414 int
intr_event_bind_ithread_cpuset(struct intr_event * ie,cpuset_t * cs)415 intr_event_bind_ithread_cpuset(struct intr_event *ie, cpuset_t *cs)
416 {
417 lwpid_t id;
418
419 mtx_lock(&ie->ie_lock);
420 if (ie->ie_thread != NULL) {
421 id = ie->ie_thread->it_thread->td_tid;
422 mtx_unlock(&ie->ie_lock);
423 return (cpuset_setthread(id, cs));
424 } else {
425 mtx_unlock(&ie->ie_lock);
426 }
427 return (ENODEV);
428 }
429
430 static struct intr_event *
intr_lookup(int irq)431 intr_lookup(int irq)
432 {
433 struct intr_event *ie;
434
435 mtx_lock(&event_lock);
436 TAILQ_FOREACH(ie, &event_list, ie_list)
437 if (ie->ie_irq == irq &&
438 (ie->ie_flags & IE_SOFT) == 0 &&
439 CK_SLIST_FIRST(&ie->ie_handlers) != NULL)
440 break;
441 mtx_unlock(&event_lock);
442 return (ie);
443 }
444
445 int
intr_setaffinity(int irq,int mode,void * m)446 intr_setaffinity(int irq, int mode, void *m)
447 {
448 struct intr_event *ie;
449 cpuset_t *mask;
450 int cpu, n;
451
452 mask = m;
453 cpu = NOCPU;
454 /*
455 * If we're setting all cpus we can unbind. Otherwise make sure
456 * only one cpu is in the set.
457 */
458 if (CPU_CMP(cpuset_root, mask)) {
459 for (n = 0; n < CPU_SETSIZE; n++) {
460 if (!CPU_ISSET(n, mask))
461 continue;
462 if (cpu != NOCPU)
463 return (EINVAL);
464 cpu = n;
465 }
466 }
467 ie = intr_lookup(irq);
468 if (ie == NULL)
469 return (ESRCH);
470 switch (mode) {
471 case CPU_WHICH_IRQ:
472 return (intr_event_bind(ie, cpu));
473 case CPU_WHICH_INTRHANDLER:
474 return (intr_event_bind_irqonly(ie, cpu));
475 case CPU_WHICH_ITHREAD:
476 return (intr_event_bind_ithread(ie, cpu));
477 default:
478 return (EINVAL);
479 }
480 }
481
482 int
intr_getaffinity(int irq,int mode,void * m)483 intr_getaffinity(int irq, int mode, void *m)
484 {
485 struct intr_event *ie;
486 struct thread *td;
487 struct proc *p;
488 cpuset_t *mask;
489 lwpid_t id;
490 int error;
491
492 mask = m;
493 ie = intr_lookup(irq);
494 if (ie == NULL)
495 return (ESRCH);
496
497 error = 0;
498 CPU_ZERO(mask);
499 switch (mode) {
500 case CPU_WHICH_IRQ:
501 case CPU_WHICH_INTRHANDLER:
502 mtx_lock(&ie->ie_lock);
503 if (ie->ie_cpu == NOCPU)
504 CPU_COPY(cpuset_root, mask);
505 else
506 CPU_SET(ie->ie_cpu, mask);
507 mtx_unlock(&ie->ie_lock);
508 break;
509 case CPU_WHICH_ITHREAD:
510 mtx_lock(&ie->ie_lock);
511 if (ie->ie_thread == NULL) {
512 mtx_unlock(&ie->ie_lock);
513 CPU_COPY(cpuset_root, mask);
514 } else {
515 id = ie->ie_thread->it_thread->td_tid;
516 mtx_unlock(&ie->ie_lock);
517 error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL);
518 if (error != 0)
519 return (error);
520 CPU_COPY(&td->td_cpuset->cs_mask, mask);
521 PROC_UNLOCK(p);
522 }
523 default:
524 return (EINVAL);
525 }
526 return (0);
527 }
528
529 int
intr_event_destroy(struct intr_event * ie)530 intr_event_destroy(struct intr_event *ie)
531 {
532
533 if (ie == NULL)
534 return (EINVAL);
535
536 mtx_lock(&event_lock);
537 mtx_lock(&ie->ie_lock);
538 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
539 mtx_unlock(&ie->ie_lock);
540 mtx_unlock(&event_lock);
541 return (EBUSY);
542 }
543 TAILQ_REMOVE(&event_list, ie, ie_list);
544 mtx_unlock(&event_lock);
545 if (ie->ie_thread != NULL)
546 ithread_destroy(ie->ie_thread);
547 mtx_unlock(&ie->ie_lock);
548 mtx_destroy(&ie->ie_lock);
549 free(ie, M_ITHREAD);
550 return (0);
551 }
552
553 static struct intr_thread *
ithread_create(const char * name)554 ithread_create(const char *name)
555 {
556 struct intr_thread *ithd;
557 struct thread *td;
558 int error;
559
560 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
561
562 error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
563 &td, RFSTOPPED | RFHIGHPID,
564 0, "intr", "%s", name);
565 if (error)
566 panic("kproc_create() failed with %d", error);
567 thread_lock(td);
568 sched_class(td, PRI_ITHD);
569 TD_SET_IWAIT(td);
570 thread_unlock(td);
571 td->td_pflags |= TDP_ITHREAD;
572 ithd->it_thread = td;
573 CTR2(KTR_INTR, "%s: created %s", __func__, name);
574 return (ithd);
575 }
576
577 static void
ithread_destroy(struct intr_thread * ithread)578 ithread_destroy(struct intr_thread *ithread)
579 {
580 struct intr_event *ie;
581 struct thread *td;
582
583 td = ithread->it_thread;
584 ie = ithread->it_event;
585
586 mtx_assert(&ie->ie_lock, MA_OWNED);
587
588 CTR2(KTR_INTR, "%s: killing %s", __func__, ie->ie_name);
589
590 thread_lock(td);
591 ithread->it_flags |= IT_DEAD;
592 if (TD_AWAITING_INTR(td)) {
593 TD_CLR_IWAIT(td);
594 sched_wakeup(td, SRQ_INTR);
595 } else
596 thread_unlock(td);
597 while (ie->ie_thread != NULL)
598 msleep(ithread, &ie->ie_lock, 0, "ithd_dth", 0);
599 }
600
601 int
intr_event_add_handler(struct intr_event * ie,const char * name,driver_filter_t filter,driver_intr_t handler,void * arg,u_char pri,enum intr_type flags,void ** cookiep)602 intr_event_add_handler(struct intr_event *ie, const char *name,
603 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
604 enum intr_type flags, void **cookiep)
605 {
606 struct intr_handler *ih, *temp_ih;
607 struct intr_handler **prevptr;
608 struct intr_thread *it;
609
610 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
611 return (EINVAL);
612
613 /* Allocate and populate an interrupt handler structure. */
614 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
615 ih->ih_filter = filter;
616 ih->ih_handler = handler;
617 ih->ih_argument = arg;
618 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
619 ih->ih_event = ie;
620 ih->ih_pri = pri;
621 if (flags & INTR_EXCL)
622 ih->ih_flags = IH_EXCLUSIVE;
623 if (flags & INTR_MPSAFE)
624 ih->ih_flags |= IH_MPSAFE;
625 if (flags & INTR_ENTROPY)
626 ih->ih_flags |= IH_ENTROPY;
627 if (flags & INTR_TYPE_NET)
628 ih->ih_flags |= IH_NET;
629
630 /* We can only have one exclusive handler in a event. */
631 mtx_lock(&ie->ie_lock);
632 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
633 if ((flags & INTR_EXCL) ||
634 (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
635 mtx_unlock(&ie->ie_lock);
636 free(ih, M_ITHREAD);
637 return (EINVAL);
638 }
639 }
640
641 /* Create a thread if we need one. */
642 while (ie->ie_thread == NULL && handler != NULL) {
643 if (ie->ie_flags & IE_ADDING_THREAD)
644 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
645 else {
646 ie->ie_flags |= IE_ADDING_THREAD;
647 mtx_unlock(&ie->ie_lock);
648 it = ithread_create("intr: newborn");
649 mtx_lock(&ie->ie_lock);
650 ie->ie_flags &= ~IE_ADDING_THREAD;
651 ie->ie_thread = it;
652 it->it_event = ie;
653 ithread_update(it);
654 wakeup(ie);
655 }
656 }
657
658 /* Add the new handler to the event in priority order. */
659 CK_SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) {
660 if (temp_ih->ih_pri > ih->ih_pri)
661 break;
662 }
663 CK_SLIST_INSERT_PREVPTR(prevptr, temp_ih, ih, ih_next);
664
665 intr_event_update(ie);
666
667 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
668 ie->ie_name);
669 mtx_unlock(&ie->ie_lock);
670
671 if (cookiep != NULL)
672 *cookiep = ih;
673 return (0);
674 }
675
676 /*
677 * Append a description preceded by a ':' to the name of the specified
678 * interrupt handler.
679 */
680 int
intr_event_describe_handler(struct intr_event * ie,void * cookie,const char * descr)681 intr_event_describe_handler(struct intr_event *ie, void *cookie,
682 const char *descr)
683 {
684 struct intr_handler *ih;
685 size_t space;
686 char *start;
687
688 mtx_lock(&ie->ie_lock);
689 #ifdef INVARIANTS
690 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
691 if (ih == cookie)
692 break;
693 }
694 if (ih == NULL) {
695 mtx_unlock(&ie->ie_lock);
696 panic("handler %p not found in interrupt event %p", cookie, ie);
697 }
698 #endif
699 ih = cookie;
700
701 /*
702 * Look for an existing description by checking for an
703 * existing ":". This assumes device names do not include
704 * colons. If one is found, prepare to insert the new
705 * description at that point. If one is not found, find the
706 * end of the name to use as the insertion point.
707 */
708 start = strchr(ih->ih_name, ':');
709 if (start == NULL)
710 start = strchr(ih->ih_name, 0);
711
712 /*
713 * See if there is enough remaining room in the string for the
714 * description + ":". The "- 1" leaves room for the trailing
715 * '\0'. The "+ 1" accounts for the colon.
716 */
717 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
718 if (strlen(descr) + 1 > space) {
719 mtx_unlock(&ie->ie_lock);
720 return (ENOSPC);
721 }
722
723 /* Append a colon followed by the description. */
724 *start = ':';
725 strcpy(start + 1, descr);
726 intr_event_update(ie);
727 mtx_unlock(&ie->ie_lock);
728 return (0);
729 }
730
731 /*
732 * Return the ie_source field from the intr_event an intr_handler is
733 * associated with.
734 */
735 void *
intr_handler_source(void * cookie)736 intr_handler_source(void *cookie)
737 {
738 struct intr_handler *ih;
739 struct intr_event *ie;
740
741 ih = (struct intr_handler *)cookie;
742 if (ih == NULL)
743 return (NULL);
744 ie = ih->ih_event;
745 KASSERT(ie != NULL,
746 ("interrupt handler \"%s\" has a NULL interrupt event",
747 ih->ih_name));
748 return (ie->ie_source);
749 }
750
751 /*
752 * If intr_event_handle() is running in the ISR context at the time of the call,
753 * then wait for it to complete.
754 */
755 static void
intr_event_barrier(struct intr_event * ie)756 intr_event_barrier(struct intr_event *ie)
757 {
758 int phase;
759
760 mtx_assert(&ie->ie_lock, MA_OWNED);
761 phase = ie->ie_phase;
762
763 /*
764 * Switch phase to direct future interrupts to the other active counter.
765 * Make sure that any preceding stores are visible before the switch.
766 */
767 KASSERT(ie->ie_active[!phase] == 0, ("idle phase has activity"));
768 atomic_store_rel_int(&ie->ie_phase, !phase);
769
770 /*
771 * This code cooperates with wait-free iteration of ie_handlers
772 * in intr_event_handle.
773 * Make sure that the removal and the phase update are not reordered
774 * with the active count check.
775 * Note that no combination of acquire and release fences can provide
776 * that guarantee as Store->Load sequences can always be reordered.
777 */
778 atomic_thread_fence_seq_cst();
779
780 /*
781 * Now wait on the inactive phase.
782 * The acquire fence is needed so that all post-barrier accesses
783 * are after the check.
784 */
785 while (ie->ie_active[phase] > 0)
786 cpu_spinwait();
787 atomic_thread_fence_acq();
788 }
789
790 static void
intr_handler_barrier(struct intr_handler * handler)791 intr_handler_barrier(struct intr_handler *handler)
792 {
793 struct intr_event *ie;
794
795 ie = handler->ih_event;
796 mtx_assert(&ie->ie_lock, MA_OWNED);
797 KASSERT((handler->ih_flags & IH_DEAD) == 0,
798 ("update for a removed handler"));
799
800 if (ie->ie_thread == NULL) {
801 intr_event_barrier(ie);
802 return;
803 }
804 if ((handler->ih_flags & IH_CHANGED) == 0) {
805 handler->ih_flags |= IH_CHANGED;
806 intr_event_schedule_thread(ie, NULL);
807 }
808 while ((handler->ih_flags & IH_CHANGED) != 0)
809 msleep(handler, &ie->ie_lock, 0, "ih_barr", 0);
810 }
811
812 /*
813 * Sleep until an ithread finishes executing an interrupt handler.
814 *
815 * XXX Doesn't currently handle interrupt filters or fast interrupt
816 * handlers. This is intended for LinuxKPI drivers only.
817 * Do not use in BSD code.
818 */
819 void
_intr_drain(int irq)820 _intr_drain(int irq)
821 {
822 struct intr_event *ie;
823 struct intr_thread *ithd;
824 struct thread *td;
825
826 ie = intr_lookup(irq);
827 if (ie == NULL)
828 return;
829 if (ie->ie_thread == NULL)
830 return;
831 ithd = ie->ie_thread;
832 td = ithd->it_thread;
833 /*
834 * We set the flag and wait for it to be cleared to avoid
835 * long delays with potentially busy interrupt handlers
836 * were we to only sample TD_AWAITING_INTR() every tick.
837 */
838 thread_lock(td);
839 if (!TD_AWAITING_INTR(td)) {
840 ithd->it_flags |= IT_WAIT;
841 while (ithd->it_flags & IT_WAIT) {
842 thread_unlock(td);
843 pause("idrain", 1);
844 thread_lock(td);
845 }
846 }
847 thread_unlock(td);
848 return;
849 }
850
851 int
intr_event_remove_handler(void * cookie)852 intr_event_remove_handler(void *cookie)
853 {
854 struct intr_handler *handler = (struct intr_handler *)cookie;
855 struct intr_event *ie;
856 struct intr_handler *ih;
857 struct intr_handler **prevptr;
858
859 if (handler == NULL)
860 return (EINVAL);
861 ie = handler->ih_event;
862 KASSERT(ie != NULL,
863 ("interrupt handler \"%s\" has a NULL interrupt event",
864 handler->ih_name));
865
866 mtx_lock(&ie->ie_lock);
867 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
868 ie->ie_name);
869 CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
870 if (ih == handler)
871 break;
872 }
873 if (ih == NULL) {
874 panic("interrupt handler \"%s\" not found in "
875 "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
876 }
877
878 if (ie->ie_thread == NULL) {
879 /*
880 * If there is no ithread, then directly remove the handler.
881 * Note that intr_event_handle() iterates ie_handlers in a
882 * lock-less fashion, so care needs to be taken to keep
883 * ie_handlers consistent and to free the removed handler only
884 * when ie_handlers is quiescent.
885 */
886 CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
887 intr_event_barrier(ie);
888 } else {
889 /*
890 * Let the interrupt thread do the job. The interrupt source is
891 * disabled when the interrupt thread is running, so it does not
892 * have to worry about interaction with intr_event_handle().
893 */
894 KASSERT((handler->ih_flags & IH_DEAD) == 0,
895 ("duplicate handle remove"));
896 handler->ih_flags |= IH_DEAD;
897 intr_event_schedule_thread(ie, NULL);
898 while (handler->ih_flags & IH_DEAD)
899 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
900 }
901 intr_event_update(ie);
902 mtx_unlock(&ie->ie_lock);
903 free(handler, M_ITHREAD);
904 return (0);
905 }
906
907 int
intr_event_suspend_handler(void * cookie)908 intr_event_suspend_handler(void *cookie)
909 {
910 struct intr_handler *handler = (struct intr_handler *)cookie;
911 struct intr_event *ie;
912
913 if (handler == NULL)
914 return (EINVAL);
915 ie = handler->ih_event;
916 KASSERT(ie != NULL,
917 ("interrupt handler \"%s\" has a NULL interrupt event",
918 handler->ih_name));
919 mtx_lock(&ie->ie_lock);
920 handler->ih_flags |= IH_SUSP;
921 intr_handler_barrier(handler);
922 mtx_unlock(&ie->ie_lock);
923 return (0);
924 }
925
926 int
intr_event_resume_handler(void * cookie)927 intr_event_resume_handler(void *cookie)
928 {
929 struct intr_handler *handler = (struct intr_handler *)cookie;
930 struct intr_event *ie;
931
932 if (handler == NULL)
933 return (EINVAL);
934 ie = handler->ih_event;
935 KASSERT(ie != NULL,
936 ("interrupt handler \"%s\" has a NULL interrupt event",
937 handler->ih_name));
938
939 /*
940 * intr_handler_barrier() acts not only as a barrier,
941 * it also allows to check for any pending interrupts.
942 */
943 mtx_lock(&ie->ie_lock);
944 handler->ih_flags &= ~IH_SUSP;
945 intr_handler_barrier(handler);
946 mtx_unlock(&ie->ie_lock);
947 return (0);
948 }
949
950 static int
intr_event_schedule_thread(struct intr_event * ie,struct trapframe * frame)951 intr_event_schedule_thread(struct intr_event *ie, struct trapframe *frame)
952 {
953 struct intr_entropy entropy;
954 struct intr_thread *it;
955 struct thread *td;
956 struct thread *ctd;
957
958 /*
959 * If no ithread or no handlers, then we have a stray interrupt.
960 */
961 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers) ||
962 ie->ie_thread == NULL)
963 return (EINVAL);
964
965 ctd = curthread;
966 it = ie->ie_thread;
967 td = it->it_thread;
968
969 /*
970 * If any of the handlers for this ithread claim to be good
971 * sources of entropy, then gather some.
972 */
973 if (ie->ie_hflags & IH_ENTROPY) {
974 entropy.event = (uintptr_t)ie;
975 entropy.td = ctd;
976 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_INTERRUPT);
977 }
978
979 KASSERT(td->td_proc != NULL, ("ithread %s has no process", ie->ie_name));
980
981 /*
982 * Set it_need to tell the thread to keep running if it is already
983 * running. Then, lock the thread and see if we actually need to
984 * put it on the runqueue.
985 *
986 * Use store_rel to arrange that the store to ih_need in
987 * swi_sched() is before the store to it_need and prepare for
988 * transfer of this order to loads in the ithread.
989 */
990 atomic_store_rel_int(&it->it_need, 1);
991 thread_lock(td);
992 if (TD_AWAITING_INTR(td)) {
993 #ifdef HWPMC_HOOKS
994 it->it_waiting = 0;
995 if (PMC_HOOK_INSTALLED_ANY())
996 PMC_SOFT_CALL_INTR_HLPR(schedule, frame);
997 #endif
998 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid,
999 td->td_name);
1000 TD_CLR_IWAIT(td);
1001 sched_wakeup(td, SRQ_INTR);
1002 } else {
1003 #ifdef HWPMC_HOOKS
1004 it->it_waiting++;
1005 if (PMC_HOOK_INSTALLED_ANY() &&
1006 (it->it_waiting >= intr_hwpmc_waiting_report_threshold))
1007 PMC_SOFT_CALL_INTR_HLPR(waiting, frame);
1008 #endif
1009 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
1010 __func__, td->td_proc->p_pid, td->td_name, it->it_need, TD_GET_STATE(td));
1011 thread_unlock(td);
1012 }
1013
1014 return (0);
1015 }
1016
1017 /*
1018 * Allow interrupt event binding for software interrupt handlers -- a no-op,
1019 * since interrupts are generated in software rather than being directed by
1020 * a PIC.
1021 */
1022 static int
swi_assign_cpu(void * arg,int cpu)1023 swi_assign_cpu(void *arg, int cpu)
1024 {
1025
1026 return (0);
1027 }
1028
1029 /*
1030 * Add a software interrupt handler to a specified event. If a given event
1031 * is not specified, then a new event is created.
1032 */
1033 int
swi_add(struct intr_event ** eventp,const char * name,driver_intr_t handler,void * arg,int pri,enum intr_type flags,void ** cookiep)1034 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
1035 void *arg, int pri, enum intr_type flags, void **cookiep)
1036 {
1037 struct intr_event *ie;
1038 int error = 0;
1039
1040 if (flags & INTR_ENTROPY)
1041 return (EINVAL);
1042
1043 ie = (eventp != NULL) ? *eventp : NULL;
1044
1045 if (ie != NULL) {
1046 if (!(ie->ie_flags & IE_SOFT))
1047 return (EINVAL);
1048 } else {
1049 error = intr_event_create(&ie, NULL, IE_SOFT, 0,
1050 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
1051 if (error)
1052 return (error);
1053 if (eventp != NULL)
1054 *eventp = ie;
1055 }
1056 if (handler != NULL) {
1057 error = intr_event_add_handler(ie, name, NULL, handler, arg,
1058 PI_SWI(pri), flags, cookiep);
1059 }
1060 return (error);
1061 }
1062
1063 /*
1064 * Schedule a software interrupt thread.
1065 */
1066 void
swi_sched(void * cookie,int flags)1067 swi_sched(void *cookie, int flags)
1068 {
1069 struct intr_handler *ih = (struct intr_handler *)cookie;
1070 struct intr_event *ie = ih->ih_event;
1071 struct intr_entropy entropy;
1072 int error __unused;
1073
1074 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
1075 ih->ih_need);
1076
1077 if ((flags & SWI_FROMNMI) == 0) {
1078 entropy.event = (uintptr_t)ih;
1079 entropy.td = curthread;
1080 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI);
1081 }
1082
1083 /*
1084 * Set ih_need for this handler so that if the ithread is already
1085 * running it will execute this handler on the next pass. Otherwise,
1086 * it will execute it the next time it runs.
1087 */
1088 ih->ih_need = 1;
1089
1090 if (flags & SWI_DELAY)
1091 return;
1092
1093 if (flags & SWI_FROMNMI) {
1094 #if defined(SMP) && (defined(__i386__) || defined(__amd64__))
1095 KASSERT(ie == clk_intr_event,
1096 ("SWI_FROMNMI used not with clk_intr_event"));
1097 ipi_self_from_nmi(IPI_SWI);
1098 #endif
1099 } else {
1100 VM_CNT_INC(v_soft);
1101 error = intr_event_schedule_thread(ie, NULL);
1102 KASSERT(error == 0, ("stray software interrupt"));
1103 }
1104 }
1105
1106 /*
1107 * Remove a software interrupt handler. Currently this code does not
1108 * remove the associated interrupt event if it becomes empty. Calling code
1109 * may do so manually via intr_event_destroy(), but that's not really
1110 * an optimal interface.
1111 */
1112 int
swi_remove(void * cookie)1113 swi_remove(void *cookie)
1114 {
1115
1116 return (intr_event_remove_handler(cookie));
1117 }
1118
1119 static void
intr_event_execute_handlers(struct proc * p,struct intr_event * ie)1120 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
1121 {
1122 struct intr_handler *ih, *ihn, *ihp;
1123
1124 ihp = NULL;
1125 CK_SLIST_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
1126 /*
1127 * If this handler is marked for death, remove it from
1128 * the list of handlers and wake up the sleeper.
1129 */
1130 if (ih->ih_flags & IH_DEAD) {
1131 mtx_lock(&ie->ie_lock);
1132 if (ihp == NULL)
1133 CK_SLIST_REMOVE_HEAD(&ie->ie_handlers, ih_next);
1134 else
1135 CK_SLIST_REMOVE_AFTER(ihp, ih_next);
1136 ih->ih_flags &= ~IH_DEAD;
1137 wakeup(ih);
1138 mtx_unlock(&ie->ie_lock);
1139 continue;
1140 }
1141
1142 /*
1143 * Now that we know that the current element won't be removed
1144 * update the previous element.
1145 */
1146 ihp = ih;
1147
1148 if ((ih->ih_flags & IH_CHANGED) != 0) {
1149 mtx_lock(&ie->ie_lock);
1150 ih->ih_flags &= ~IH_CHANGED;
1151 wakeup(ih);
1152 mtx_unlock(&ie->ie_lock);
1153 }
1154
1155 /* Skip filter only handlers */
1156 if (ih->ih_handler == NULL)
1157 continue;
1158
1159 /* Skip suspended handlers */
1160 if ((ih->ih_flags & IH_SUSP) != 0)
1161 continue;
1162
1163 /*
1164 * For software interrupt threads, we only execute
1165 * handlers that have their need flag set. Hardware
1166 * interrupt threads always invoke all of their handlers.
1167 *
1168 * ih_need can only be 0 or 1. Failed cmpset below
1169 * means that there is no request to execute handlers,
1170 * so a retry of the cmpset is not needed.
1171 */
1172 if ((ie->ie_flags & IE_SOFT) != 0 &&
1173 atomic_cmpset_int(&ih->ih_need, 1, 0) == 0)
1174 continue;
1175
1176 /* Execute this handler. */
1177 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1178 __func__, p->p_pid, (void *)ih->ih_handler,
1179 ih->ih_argument, ih->ih_name, ih->ih_flags);
1180
1181 if (!(ih->ih_flags & IH_MPSAFE))
1182 mtx_lock(&Giant);
1183 ih->ih_handler(ih->ih_argument);
1184 if (!(ih->ih_flags & IH_MPSAFE))
1185 mtx_unlock(&Giant);
1186 }
1187 }
1188
1189 static void
ithread_execute_handlers(struct proc * p,struct intr_event * ie)1190 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1191 {
1192
1193 /* Interrupt handlers should not sleep. */
1194 if (!(ie->ie_flags & IE_SOFT))
1195 THREAD_NO_SLEEPING();
1196 intr_event_execute_handlers(p, ie);
1197 if (!(ie->ie_flags & IE_SOFT))
1198 THREAD_SLEEPING_OK();
1199
1200 /*
1201 * Interrupt storm handling:
1202 *
1203 * If this interrupt source is currently storming, then throttle
1204 * it to only fire the handler once per clock tick.
1205 *
1206 * If this interrupt source is not currently storming, but the
1207 * number of back to back interrupts exceeds the storm threshold,
1208 * then enter storming mode.
1209 */
1210 if (__predict_false(intr_storm_threshold != 0 &&
1211 ie->ie_count >= intr_storm_threshold &&
1212 (ie->ie_flags & IE_SOFT) == 0)) {
1213 /* Report the message only once every second. */
1214 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1215 printf(
1216 "interrupt storm detected on \"%s\"; throttling interrupt source\n",
1217 ie->ie_name);
1218 }
1219 pause("istorm", 1);
1220 } else
1221 ie->ie_count++;
1222
1223 /*
1224 * Now that all the handlers have had a chance to run, reenable
1225 * the interrupt source.
1226 */
1227 if (ie->ie_post_ithread != NULL)
1228 ie->ie_post_ithread(ie->ie_source);
1229 }
1230
1231 /*
1232 * This is the main code for interrupt threads.
1233 */
1234 static void
ithread_loop(void * arg)1235 ithread_loop(void *arg)
1236 {
1237 struct epoch_tracker et;
1238 struct intr_thread *ithd;
1239 struct intr_event *ie;
1240 struct thread *td;
1241 struct proc *p;
1242 int epoch_count;
1243 bool needs_epoch;
1244
1245 td = curthread;
1246 p = td->td_proc;
1247 ithd = (struct intr_thread *)arg;
1248 KASSERT(ithd->it_thread == td,
1249 ("%s: ithread and proc linkage out of sync", __func__));
1250 ie = ithd->it_event;
1251 ie->ie_count = 0;
1252
1253 /*
1254 * As long as we have interrupts outstanding, go through the
1255 * list of handlers, giving each one a go at it.
1256 */
1257 for (;;) {
1258 /*
1259 * If we are an orphaned thread, then just die.
1260 */
1261 if (__predict_false((ithd->it_flags & IT_DEAD) != 0)) {
1262 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1263 p->p_pid, td->td_name);
1264 mtx_lock(&ie->ie_lock);
1265 ie->ie_thread = NULL;
1266 wakeup(ithd);
1267 mtx_unlock(&ie->ie_lock);
1268
1269 free(ithd, M_ITHREAD);
1270 kthread_exit();
1271 }
1272
1273 /*
1274 * Service interrupts. If another interrupt arrives while
1275 * we are running, it will set it_need to note that we
1276 * should make another pass.
1277 *
1278 * The load_acq part of the following cmpset ensures
1279 * that the load of ih_need in ithread_execute_handlers()
1280 * is ordered after the load of it_need here.
1281 */
1282 needs_epoch =
1283 (atomic_load_int(&ie->ie_hflags) & IH_NET) != 0;
1284 if (needs_epoch) {
1285 epoch_count = 0;
1286 NET_EPOCH_ENTER(et);
1287 }
1288 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) {
1289 ithread_execute_handlers(p, ie);
1290 if (needs_epoch &&
1291 ++epoch_count >= intr_epoch_batch) {
1292 NET_EPOCH_EXIT(et);
1293 epoch_count = 0;
1294 NET_EPOCH_ENTER(et);
1295 }
1296 }
1297 if (needs_epoch)
1298 NET_EPOCH_EXIT(et);
1299 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1300 mtx_assert(&Giant, MA_NOTOWNED);
1301
1302 /*
1303 * Processed all our interrupts. Now get the sched
1304 * lock. This may take a while and it_need may get
1305 * set again, so we have to check it again.
1306 */
1307 thread_lock(td);
1308 if (atomic_load_acq_int(&ithd->it_need) == 0 &&
1309 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) {
1310 TD_SET_IWAIT(td);
1311 ie->ie_count = 0;
1312 mi_switch(SW_VOL | SWT_IWAIT);
1313 } else if ((ithd->it_flags & IT_WAIT) != 0) {
1314 ithd->it_flags &= ~IT_WAIT;
1315 thread_unlock(td);
1316 wakeup(ithd);
1317 } else
1318 thread_unlock(td);
1319 }
1320 }
1321
1322 /*
1323 * Main interrupt handling body.
1324 *
1325 * Input:
1326 * o ie: the event connected to this interrupt.
1327 * o frame: some archs (i.e. i386) pass a frame to some.
1328 * handlers as their main argument.
1329 * Return value:
1330 * o 0: everything ok.
1331 * o EINVAL: stray interrupt.
1332 */
1333 int
intr_event_handle(struct intr_event * ie,struct trapframe * frame)1334 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1335 {
1336 struct intr_handler *ih;
1337 struct trapframe *oldframe;
1338 struct thread *td;
1339 int phase;
1340 int ret;
1341 bool filter, thread;
1342
1343 td = curthread;
1344
1345 #ifdef KSTACK_USAGE_PROF
1346 intr_prof_stack_use(td, frame);
1347 #endif
1348
1349 /* An interrupt with no event or handlers is a stray interrupt. */
1350 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers))
1351 return (EINVAL);
1352
1353 /*
1354 * Execute fast interrupt handlers directly.
1355 * To support clock handlers, if a handler registers
1356 * with a NULL argument, then we pass it a pointer to
1357 * a trapframe as its argument.
1358 */
1359 td->td_intr_nesting_level++;
1360 filter = false;
1361 thread = false;
1362 ret = 0;
1363 critical_enter();
1364 oldframe = td->td_intr_frame;
1365 td->td_intr_frame = frame;
1366
1367 phase = ie->ie_phase;
1368 atomic_add_int(&ie->ie_active[phase], 1);
1369
1370 /*
1371 * This fence is required to ensure that no later loads are
1372 * re-ordered before the ie_active store.
1373 */
1374 atomic_thread_fence_seq_cst();
1375
1376 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
1377 if ((ih->ih_flags & IH_SUSP) != 0)
1378 continue;
1379 if ((ie->ie_flags & IE_SOFT) != 0 && ih->ih_need == 0)
1380 continue;
1381 if (ih->ih_filter == NULL) {
1382 thread = true;
1383 continue;
1384 }
1385 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1386 ih->ih_filter, ih->ih_argument == NULL ? frame :
1387 ih->ih_argument, ih->ih_name);
1388 if (ih->ih_argument == NULL)
1389 ret = ih->ih_filter(frame);
1390 else
1391 ret = ih->ih_filter(ih->ih_argument);
1392 #ifdef HWPMC_HOOKS
1393 PMC_SOFT_CALL_TF( , , intr, all, frame);
1394 #endif
1395 KASSERT(ret == FILTER_STRAY ||
1396 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1397 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1398 ("%s: incorrect return value %#x from %s", __func__, ret,
1399 ih->ih_name));
1400 filter = filter || ret == FILTER_HANDLED;
1401 #ifdef HWPMC_HOOKS
1402 if (ret & FILTER_SCHEDULE_THREAD)
1403 PMC_SOFT_CALL_TF( , , intr, ithread, frame);
1404 else if (ret & FILTER_HANDLED)
1405 PMC_SOFT_CALL_TF( , , intr, filter, frame);
1406 else if (ret == FILTER_STRAY)
1407 PMC_SOFT_CALL_TF( , , intr, stray, frame);
1408 #endif
1409
1410 /*
1411 * Wrapper handler special handling:
1412 *
1413 * in some particular cases (like pccard and pccbb),
1414 * the _real_ device handler is wrapped in a couple of
1415 * functions - a filter wrapper and an ithread wrapper.
1416 * In this case (and just in this case), the filter wrapper
1417 * could ask the system to schedule the ithread and mask
1418 * the interrupt source if the wrapped handler is composed
1419 * of just an ithread handler.
1420 *
1421 * TODO: write a generic wrapper to avoid people rolling
1422 * their own.
1423 */
1424 if (!thread) {
1425 if (ret == FILTER_SCHEDULE_THREAD)
1426 thread = true;
1427 }
1428 }
1429 atomic_add_rel_int(&ie->ie_active[phase], -1);
1430
1431 td->td_intr_frame = oldframe;
1432
1433 if (thread) {
1434 if (ie->ie_pre_ithread != NULL)
1435 ie->ie_pre_ithread(ie->ie_source);
1436 } else {
1437 if (ie->ie_post_filter != NULL)
1438 ie->ie_post_filter(ie->ie_source);
1439 }
1440
1441 /* Schedule the ithread if needed. */
1442 if (thread) {
1443 int error __unused;
1444
1445 error = intr_event_schedule_thread(ie, frame);
1446 KASSERT(error == 0, ("bad stray interrupt"));
1447 }
1448 critical_exit();
1449 td->td_intr_nesting_level--;
1450 #ifdef notyet
1451 /* The interrupt is not aknowledged by any filter and has no ithread. */
1452 if (!thread && !filter)
1453 return (EINVAL);
1454 #endif
1455 return (0);
1456 }
1457
1458 #ifdef DDB
1459 /*
1460 * Dump details about an interrupt handler
1461 */
1462 static void
db_dump_intrhand(struct intr_handler * ih)1463 db_dump_intrhand(struct intr_handler *ih)
1464 {
1465 int comma;
1466
1467 db_printf("\t%-10s ", ih->ih_name);
1468 switch (ih->ih_pri) {
1469 case PI_REALTIME:
1470 db_printf("CLK ");
1471 break;
1472 case PI_INTR:
1473 db_printf("INTR");
1474 break;
1475 default:
1476 if (ih->ih_pri >= PI_SOFT)
1477 db_printf("SWI ");
1478 else
1479 db_printf("%4u", ih->ih_pri);
1480 break;
1481 }
1482 db_printf(" ");
1483 if (ih->ih_filter != NULL) {
1484 db_printf("[F]");
1485 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1486 }
1487 if (ih->ih_handler != NULL) {
1488 if (ih->ih_filter != NULL)
1489 db_printf(",");
1490 db_printf("[H]");
1491 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1492 }
1493 db_printf("(%p)", ih->ih_argument);
1494 if (ih->ih_need ||
1495 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1496 IH_MPSAFE)) != 0) {
1497 db_printf(" {");
1498 comma = 0;
1499 if (ih->ih_flags & IH_EXCLUSIVE) {
1500 if (comma)
1501 db_printf(", ");
1502 db_printf("EXCL");
1503 comma = 1;
1504 }
1505 if (ih->ih_flags & IH_ENTROPY) {
1506 if (comma)
1507 db_printf(", ");
1508 db_printf("ENTROPY");
1509 comma = 1;
1510 }
1511 if (ih->ih_flags & IH_DEAD) {
1512 if (comma)
1513 db_printf(", ");
1514 db_printf("DEAD");
1515 comma = 1;
1516 }
1517 if (ih->ih_flags & IH_MPSAFE) {
1518 if (comma)
1519 db_printf(", ");
1520 db_printf("MPSAFE");
1521 comma = 1;
1522 }
1523 if (ih->ih_need) {
1524 if (comma)
1525 db_printf(", ");
1526 db_printf("NEED");
1527 }
1528 db_printf("}");
1529 }
1530 db_printf("\n");
1531 }
1532
1533 /*
1534 * Dump details about a event.
1535 */
1536 void
db_dump_intr_event(struct intr_event * ie,int handlers)1537 db_dump_intr_event(struct intr_event *ie, int handlers)
1538 {
1539 struct intr_handler *ih;
1540 struct intr_thread *it;
1541 int comma;
1542
1543 db_printf("%s ", ie->ie_fullname);
1544 it = ie->ie_thread;
1545 if (it != NULL)
1546 db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1547 else
1548 db_printf("(no thread)");
1549 if ((ie->ie_flags & (IE_SOFT | IE_ADDING_THREAD)) != 0 ||
1550 (it != NULL && it->it_need)) {
1551 db_printf(" {");
1552 comma = 0;
1553 if (ie->ie_flags & IE_SOFT) {
1554 db_printf("SOFT");
1555 comma = 1;
1556 }
1557 if (ie->ie_flags & IE_ADDING_THREAD) {
1558 if (comma)
1559 db_printf(", ");
1560 db_printf("ADDING_THREAD");
1561 comma = 1;
1562 }
1563 if (it != NULL && it->it_need) {
1564 if (comma)
1565 db_printf(", ");
1566 db_printf("NEED");
1567 }
1568 db_printf("}");
1569 }
1570 db_printf("\n");
1571
1572 if (handlers)
1573 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next)
1574 db_dump_intrhand(ih);
1575 }
1576
1577 /*
1578 * Dump data about interrupt handlers
1579 */
DB_SHOW_COMMAND_FLAGS(intr,db_show_intr,DB_CMD_MEMSAFE)1580 DB_SHOW_COMMAND_FLAGS(intr, db_show_intr, DB_CMD_MEMSAFE)
1581 {
1582 struct intr_event *ie;
1583 int all, verbose;
1584
1585 verbose = strchr(modif, 'v') != NULL;
1586 all = strchr(modif, 'a') != NULL;
1587 TAILQ_FOREACH(ie, &event_list, ie_list) {
1588 if (!all && CK_SLIST_EMPTY(&ie->ie_handlers))
1589 continue;
1590 db_dump_intr_event(ie, verbose);
1591 if (db_pager_quit)
1592 break;
1593 }
1594 }
1595 #endif /* DDB */
1596
1597 /*
1598 * Start standard software interrupt threads
1599 */
1600 static void
start_softintr(void * dummy)1601 start_softintr(void *dummy)
1602 {
1603
1604 if (swi_add(&clk_intr_event, "clk", NULL, NULL, SWI_CLOCK,
1605 INTR_MPSAFE, NULL))
1606 panic("died while creating clk swi ithread");
1607 }
1608 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1609 NULL);
1610
1611 /*
1612 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1613 * The data for this machine dependent, and the declarations are in machine
1614 * dependent code. The layout of intrnames and intrcnt however is machine
1615 * independent.
1616 *
1617 * We do not know the length of intrcnt and intrnames at compile time, so
1618 * calculate things at run time.
1619 */
1620 static int
sysctl_intrnames(SYSCTL_HANDLER_ARGS)1621 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1622 {
1623 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1624 }
1625
1626 SYSCTL_PROC(_hw, OID_AUTO, intrnames,
1627 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
1628 sysctl_intrnames, "",
1629 "Interrupt Names");
1630
1631 static int
sysctl_intrcnt(SYSCTL_HANDLER_ARGS)1632 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1633 {
1634 #ifdef SCTL_MASK32
1635 uint32_t *intrcnt32;
1636 unsigned i;
1637 int error;
1638
1639 if (req->flags & SCTL_MASK32) {
1640 if (!req->oldptr)
1641 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1642 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1643 if (intrcnt32 == NULL)
1644 return (ENOMEM);
1645 for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1646 intrcnt32[i] = intrcnt[i];
1647 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1648 free(intrcnt32, M_TEMP);
1649 return (error);
1650 }
1651 #endif
1652 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1653 }
1654
1655 SYSCTL_PROC(_hw, OID_AUTO, intrcnt,
1656 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
1657 sysctl_intrcnt, "",
1658 "Interrupt Counts");
1659
1660 #ifdef DDB
1661 /*
1662 * DDB command to dump the interrupt statistics.
1663 */
DB_SHOW_COMMAND_FLAGS(intrcnt,db_show_intrcnt,DB_CMD_MEMSAFE)1664 DB_SHOW_COMMAND_FLAGS(intrcnt, db_show_intrcnt, DB_CMD_MEMSAFE)
1665 {
1666 u_long *i;
1667 char *cp;
1668 u_int j;
1669
1670 cp = intrnames;
1671 j = 0;
1672 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1673 i++, j++) {
1674 if (*cp == '\0')
1675 break;
1676 if (*i != 0)
1677 db_printf("%s\t%lu\n", cp, *i);
1678 cp += strlen(cp) + 1;
1679 }
1680 }
1681 #endif
1682