2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
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.
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.
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
33 #include "opt_kstack_usage_prof.h"
35 #include <sys/param.h>
38 #include <sys/cpuset.h>
39 #include <sys/rtprio.h>
40 #include <sys/systm.h>
41 #include <sys/interrupt.h>
42 #include <sys/kernel.h>
43 #include <sys/kthread.h>
45 #include <sys/limits.h>
47 #include <sys/malloc.h>
48 #include <sys/mutex.h>
51 #include <sys/random.h>
52 #include <sys/resourcevar.h>
53 #include <sys/sched.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/stdarg.h>
65 #include <ddb/db_sym.h>
69 * Describe an interrupt thread. There is one of these per interrupt event.
72 struct intr_event *it_event;
73 struct thread *it_thread; /* Kernel thread. */
74 int it_flags; /* (j) IT_* flags. */
75 int it_need; /* Needs service. */
78 /* Interrupt thread flags kept in it_flags */
79 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */
80 #define IT_WAIT 0x000002 /* Thread is waiting for completion. */
87 struct intr_event *clk_intr_event;
88 struct intr_event *tty_intr_event;
90 struct proc *intrproc;
92 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
94 static int intr_storm_threshold = 1000;
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 TAILQ_HEAD(, intr_event) event_list =
99 TAILQ_HEAD_INITIALIZER(event_list);
100 static struct mtx event_lock;
101 MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF);
103 static void intr_event_update(struct intr_event *ie);
104 static int intr_event_schedule_thread(struct intr_event *ie);
105 static struct intr_thread *ithread_create(const char *name);
106 static void ithread_destroy(struct intr_thread *ithread);
107 static void ithread_execute_handlers(struct proc *p,
108 struct intr_event *ie);
109 static void ithread_loop(void *);
110 static void ithread_update(struct intr_thread *ithd);
111 static void start_softintr(void *);
113 /* Map an interrupt type to an ithread priority. */
115 intr_priority(enum intr_type flags)
119 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
120 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
141 pri = PI_DULL; /* don't care */
144 /* We didn't specify an interrupt level. */
145 panic("intr_priority: no interrupt type in flags");
152 * Update an ithread based on the associated intr_event.
155 ithread_update(struct intr_thread *ithd)
157 struct intr_event *ie;
162 td = ithd->it_thread;
163 mtx_assert(&ie->ie_lock, MA_OWNED);
165 /* Determine the overall priority of this event. */
166 if (CK_SLIST_EMPTY(&ie->ie_handlers))
169 pri = CK_SLIST_FIRST(&ie->ie_handlers)->ih_pri;
171 /* Update name and priority. */
172 strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
174 sched_clear_tdname(td);
182 * Regenerate the full name of an interrupt event and update its priority.
185 intr_event_update(struct intr_event *ie)
187 struct intr_handler *ih;
191 /* Start off with no entropy and just the name of the event. */
192 mtx_assert(&ie->ie_lock, MA_OWNED);
193 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
194 ie->ie_flags &= ~IE_ENTROPY;
198 /* Run through all the handlers updating values. */
199 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
200 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
201 sizeof(ie->ie_fullname)) {
202 strcat(ie->ie_fullname, " ");
203 strcat(ie->ie_fullname, ih->ih_name);
207 if (ih->ih_flags & IH_ENTROPY)
208 ie->ie_flags |= IE_ENTROPY;
212 * If the handler names were too long, add +'s to indicate missing
213 * names. If we run out of room and still have +'s to add, change
214 * the last character from a + to a *.
216 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
217 while (missed-- > 0) {
218 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
225 strcat(ie->ie_fullname, " +");
228 strcat(ie->ie_fullname, "+");
232 * If this event has an ithread, update it's priority and
235 if (ie->ie_thread != NULL)
236 ithread_update(ie->ie_thread);
237 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
241 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
242 void (*pre_ithread)(void *), void (*post_ithread)(void *),
243 void (*post_filter)(void *), int (*assign_cpu)(void *, int),
244 const char *fmt, ...)
246 struct intr_event *ie;
249 /* The only valid flag during creation is IE_SOFT. */
250 if ((flags & ~IE_SOFT) != 0)
252 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
253 ie->ie_source = source;
254 ie->ie_pre_ithread = pre_ithread;
255 ie->ie_post_ithread = post_ithread;
256 ie->ie_post_filter = post_filter;
257 ie->ie_assign_cpu = assign_cpu;
258 ie->ie_flags = flags;
261 CK_SLIST_INIT(&ie->ie_handlers);
262 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
265 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
267 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
268 mtx_lock(&event_lock);
269 TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
270 mtx_unlock(&event_lock);
273 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
278 * Bind an interrupt event to the specified CPU. Note that not all
279 * platforms support binding an interrupt to a CPU. For those
280 * platforms this request will fail. Using a cpu id of NOCPU unbinds
281 * the interrupt event.
284 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread)
289 /* Need a CPU to bind to. */
290 if (cpu != NOCPU && CPU_ABSENT(cpu))
293 if (ie->ie_assign_cpu == NULL)
296 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
301 * If we have any ithreads try to set their mask first to verify
305 mtx_lock(&ie->ie_lock);
306 if (ie->ie_thread != NULL) {
307 id = ie->ie_thread->it_thread->td_tid;
308 mtx_unlock(&ie->ie_lock);
309 error = cpuset_setithread(id, cpu);
313 mtx_unlock(&ie->ie_lock);
316 error = ie->ie_assign_cpu(ie->ie_source, cpu);
319 mtx_lock(&ie->ie_lock);
320 if (ie->ie_thread != NULL) {
322 id = ie->ie_thread->it_thread->td_tid;
323 mtx_unlock(&ie->ie_lock);
324 (void)cpuset_setithread(id, cpu);
326 mtx_unlock(&ie->ie_lock);
332 mtx_lock(&ie->ie_lock);
334 mtx_unlock(&ie->ie_lock);
341 * Bind an interrupt event to the specified CPU. For supported platforms, any
342 * associated ithreads as well as the primary interrupt context will be bound
343 * to the specificed CPU.
346 intr_event_bind(struct intr_event *ie, int cpu)
349 return (_intr_event_bind(ie, cpu, true, true));
353 * Bind an interrupt event to the specified CPU, but do not bind associated
357 intr_event_bind_irqonly(struct intr_event *ie, int cpu)
360 return (_intr_event_bind(ie, cpu, true, false));
364 * Bind an interrupt event's ithread to the specified CPU.
367 intr_event_bind_ithread(struct intr_event *ie, int cpu)
370 return (_intr_event_bind(ie, cpu, false, true));
373 static struct intr_event *
376 struct intr_event *ie;
378 mtx_lock(&event_lock);
379 TAILQ_FOREACH(ie, &event_list, ie_list)
380 if (ie->ie_irq == irq &&
381 (ie->ie_flags & IE_SOFT) == 0 &&
382 CK_SLIST_FIRST(&ie->ie_handlers) != NULL)
384 mtx_unlock(&event_lock);
389 intr_setaffinity(int irq, int mode, void *m)
391 struct intr_event *ie;
398 * If we're setting all cpus we can unbind. Otherwise make sure
399 * only one cpu is in the set.
401 if (CPU_CMP(cpuset_root, mask)) {
402 for (n = 0; n < CPU_SETSIZE; n++) {
403 if (!CPU_ISSET(n, mask))
410 ie = intr_lookup(irq);
415 return (intr_event_bind(ie, cpu));
416 case CPU_WHICH_INTRHANDLER:
417 return (intr_event_bind_irqonly(ie, cpu));
418 case CPU_WHICH_ITHREAD:
419 return (intr_event_bind_ithread(ie, cpu));
426 intr_getaffinity(int irq, int mode, void *m)
428 struct intr_event *ie;
436 ie = intr_lookup(irq);
444 case CPU_WHICH_INTRHANDLER:
445 mtx_lock(&ie->ie_lock);
446 if (ie->ie_cpu == NOCPU)
447 CPU_COPY(cpuset_root, mask);
449 CPU_SET(ie->ie_cpu, mask);
450 mtx_unlock(&ie->ie_lock);
452 case CPU_WHICH_ITHREAD:
453 mtx_lock(&ie->ie_lock);
454 if (ie->ie_thread == NULL) {
455 mtx_unlock(&ie->ie_lock);
456 CPU_COPY(cpuset_root, mask);
458 id = ie->ie_thread->it_thread->td_tid;
459 mtx_unlock(&ie->ie_lock);
460 error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL);
463 CPU_COPY(&td->td_cpuset->cs_mask, mask);
473 intr_event_destroy(struct intr_event *ie)
476 mtx_lock(&event_lock);
477 mtx_lock(&ie->ie_lock);
478 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
479 mtx_unlock(&ie->ie_lock);
480 mtx_unlock(&event_lock);
483 TAILQ_REMOVE(&event_list, ie, ie_list);
485 if (ie->ie_thread != NULL) {
486 ithread_destroy(ie->ie_thread);
487 ie->ie_thread = NULL;
490 mtx_unlock(&ie->ie_lock);
491 mtx_unlock(&event_lock);
492 mtx_destroy(&ie->ie_lock);
497 static struct intr_thread *
498 ithread_create(const char *name)
500 struct intr_thread *ithd;
504 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
506 error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
507 &td, RFSTOPPED | RFHIGHPID,
508 0, "intr", "%s", name);
510 panic("kproc_create() failed with %d", error);
512 sched_class(td, PRI_ITHD);
515 td->td_pflags |= TDP_ITHREAD;
516 ithd->it_thread = td;
517 CTR2(KTR_INTR, "%s: created %s", __func__, name);
522 ithread_destroy(struct intr_thread *ithread)
526 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
527 td = ithread->it_thread;
529 ithread->it_flags |= IT_DEAD;
530 if (TD_AWAITING_INTR(td)) {
532 sched_add(td, SRQ_INTR);
538 intr_event_add_handler(struct intr_event *ie, const char *name,
539 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
540 enum intr_type flags, void **cookiep)
542 struct intr_handler *ih, *temp_ih;
543 struct intr_handler **prevptr;
544 struct intr_thread *it;
546 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
549 /* Allocate and populate an interrupt handler structure. */
550 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
551 ih->ih_filter = filter;
552 ih->ih_handler = handler;
553 ih->ih_argument = arg;
554 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
557 if (flags & INTR_EXCL)
558 ih->ih_flags = IH_EXCLUSIVE;
559 if (flags & INTR_MPSAFE)
560 ih->ih_flags |= IH_MPSAFE;
561 if (flags & INTR_ENTROPY)
562 ih->ih_flags |= IH_ENTROPY;
564 /* We can only have one exclusive handler in a event. */
565 mtx_lock(&ie->ie_lock);
566 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
567 if ((flags & INTR_EXCL) ||
568 (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
569 mtx_unlock(&ie->ie_lock);
575 /* Create a thread if we need one. */
576 while (ie->ie_thread == NULL && handler != NULL) {
577 if (ie->ie_flags & IE_ADDING_THREAD)
578 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
580 ie->ie_flags |= IE_ADDING_THREAD;
581 mtx_unlock(&ie->ie_lock);
582 it = ithread_create("intr: newborn");
583 mtx_lock(&ie->ie_lock);
584 ie->ie_flags &= ~IE_ADDING_THREAD;
592 /* Add the new handler to the event in priority order. */
593 CK_SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) {
594 if (temp_ih->ih_pri > ih->ih_pri)
597 CK_SLIST_INSERT_PREVPTR(prevptr, temp_ih, ih, ih_next);
599 intr_event_update(ie);
601 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
603 mtx_unlock(&ie->ie_lock);
611 * Append a description preceded by a ':' to the name of the specified
615 intr_event_describe_handler(struct intr_event *ie, void *cookie,
618 struct intr_handler *ih;
622 mtx_lock(&ie->ie_lock);
624 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
629 mtx_unlock(&ie->ie_lock);
630 panic("handler %p not found in interrupt event %p", cookie, ie);
636 * Look for an existing description by checking for an
637 * existing ":". This assumes device names do not include
638 * colons. If one is found, prepare to insert the new
639 * description at that point. If one is not found, find the
640 * end of the name to use as the insertion point.
642 start = strchr(ih->ih_name, ':');
644 start = strchr(ih->ih_name, 0);
647 * See if there is enough remaining room in the string for the
648 * description + ":". The "- 1" leaves room for the trailing
649 * '\0'. The "+ 1" accounts for the colon.
651 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
652 if (strlen(descr) + 1 > space) {
653 mtx_unlock(&ie->ie_lock);
657 /* Append a colon followed by the description. */
659 strcpy(start + 1, descr);
660 intr_event_update(ie);
661 mtx_unlock(&ie->ie_lock);
666 * Return the ie_source field from the intr_event an intr_handler is
670 intr_handler_source(void *cookie)
672 struct intr_handler *ih;
673 struct intr_event *ie;
675 ih = (struct intr_handler *)cookie;
680 ("interrupt handler \"%s\" has a NULL interrupt event",
682 return (ie->ie_source);
686 * If intr_event_handle() is running in the ISR context at the time of the call,
687 * then wait for it to complete.
690 intr_event_barrier(struct intr_event *ie)
694 mtx_assert(&ie->ie_lock, MA_OWNED);
695 phase = ie->ie_phase;
698 * Switch phase to direct future interrupts to the other active counter.
699 * Make sure that any preceding stores are visible before the switch.
701 KASSERT(ie->ie_active[!phase] == 0, ("idle phase has activity"));
702 atomic_store_rel_int(&ie->ie_phase, !phase);
705 * This code cooperates with wait-free iteration of ie_handlers
706 * in intr_event_handle.
707 * Make sure that the removal and the phase update are not reordered
708 * with the active count check.
709 * Note that no combination of acquire and release fences can provide
710 * that guarantee as Store->Load sequences can always be reordered.
712 atomic_thread_fence_seq_cst();
715 * Now wait on the inactive phase.
716 * The acquire fence is needed so that that all post-barrier accesses
717 * are after the check.
719 while (ie->ie_active[phase] > 0)
721 atomic_thread_fence_acq();
725 intr_handler_barrier(struct intr_handler *handler)
727 struct intr_event *ie;
729 ie = handler->ih_event;
730 mtx_assert(&ie->ie_lock, MA_OWNED);
731 KASSERT((handler->ih_flags & IH_DEAD) == 0,
732 ("update for a removed handler"));
734 if (ie->ie_thread == NULL) {
735 intr_event_barrier(ie);
738 if ((handler->ih_flags & IH_CHANGED) == 0) {
739 handler->ih_flags |= IH_CHANGED;
740 intr_event_schedule_thread(ie);
742 while ((handler->ih_flags & IH_CHANGED) != 0)
743 msleep(handler, &ie->ie_lock, 0, "ih_barr", 0);
747 * Sleep until an ithread finishes executing an interrupt handler.
749 * XXX Doesn't currently handle interrupt filters or fast interrupt
750 * handlers. This is intended for compatibility with linux drivers
751 * only. Do not use in BSD code.
756 struct intr_event *ie;
757 struct intr_thread *ithd;
760 ie = intr_lookup(irq);
763 if (ie->ie_thread == NULL)
765 ithd = ie->ie_thread;
766 td = ithd->it_thread;
768 * We set the flag and wait for it to be cleared to avoid
769 * long delays with potentially busy interrupt handlers
770 * were we to only sample TD_AWAITING_INTR() every tick.
773 if (!TD_AWAITING_INTR(td)) {
774 ithd->it_flags |= IT_WAIT;
775 while (ithd->it_flags & IT_WAIT) {
786 intr_event_remove_handler(void *cookie)
788 struct intr_handler *handler = (struct intr_handler *)cookie;
789 struct intr_event *ie;
790 struct intr_handler *ih;
791 struct intr_handler **prevptr;
798 ie = handler->ih_event;
800 ("interrupt handler \"%s\" has a NULL interrupt event",
803 mtx_lock(&ie->ie_lock);
804 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
806 CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
811 panic("interrupt handler \"%s\" not found in "
812 "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
816 * If there is no ithread, then directly remove the handler. Note that
817 * intr_event_handle() iterates ie_handlers in a lock-less fashion, so
818 * care needs to be taken to keep ie_handlers consistent and to free
819 * the removed handler only when ie_handlers is quiescent.
821 if (ie->ie_thread == NULL) {
822 CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
823 intr_event_barrier(ie);
824 intr_event_update(ie);
825 mtx_unlock(&ie->ie_lock);
826 free(handler, M_ITHREAD);
831 * Let the interrupt thread do the job.
832 * The interrupt source is disabled when the interrupt thread is
833 * running, so it does not have to worry about interaction with
834 * intr_event_handle().
836 KASSERT((handler->ih_flags & IH_DEAD) == 0,
837 ("duplicate handle remove"));
838 handler->ih_flags |= IH_DEAD;
839 intr_event_schedule_thread(ie);
840 while (handler->ih_flags & IH_DEAD)
841 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
842 intr_event_update(ie);
846 * XXX: This could be bad in the case of ppbus(8). Also, I think
847 * this could lead to races of stale data when servicing an
851 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
852 if (ih->ih_handler != NULL) {
858 ithread_destroy(ie->ie_thread);
859 ie->ie_thread = NULL;
862 mtx_unlock(&ie->ie_lock);
863 free(handler, M_ITHREAD);
868 intr_event_suspend_handler(void *cookie)
870 struct intr_handler *handler = (struct intr_handler *)cookie;
871 struct intr_event *ie;
875 ie = handler->ih_event;
877 ("interrupt handler \"%s\" has a NULL interrupt event",
879 mtx_lock(&ie->ie_lock);
880 handler->ih_flags |= IH_SUSP;
881 intr_handler_barrier(handler);
882 mtx_unlock(&ie->ie_lock);
887 intr_event_resume_handler(void *cookie)
889 struct intr_handler *handler = (struct intr_handler *)cookie;
890 struct intr_event *ie;
894 ie = handler->ih_event;
896 ("interrupt handler \"%s\" has a NULL interrupt event",
900 * intr_handler_barrier() acts not only as a barrier,
901 * it also allows to check for any pending interrupts.
903 mtx_lock(&ie->ie_lock);
904 handler->ih_flags &= ~IH_SUSP;
905 intr_handler_barrier(handler);
906 mtx_unlock(&ie->ie_lock);
911 intr_event_schedule_thread(struct intr_event *ie)
913 struct intr_entropy entropy;
914 struct intr_thread *it;
919 * If no ithread or no handlers, then we have a stray interrupt.
921 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers) ||
922 ie->ie_thread == NULL)
930 * If any of the handlers for this ithread claim to be good
931 * sources of entropy, then gather some.
933 if (ie->ie_flags & IE_ENTROPY) {
934 entropy.event = (uintptr_t)ie;
936 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_INTERRUPT);
939 KASSERT(td->td_proc != NULL, ("ithread %s has no process", ie->ie_name));
942 * Set it_need to tell the thread to keep running if it is already
943 * running. Then, lock the thread and see if we actually need to
944 * put it on the runqueue.
946 * Use store_rel to arrange that the store to ih_need in
947 * swi_sched() is before the store to it_need and prepare for
948 * transfer of this order to loads in the ithread.
950 atomic_store_rel_int(&it->it_need, 1);
952 if (TD_AWAITING_INTR(td)) {
953 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid,
956 sched_add(td, SRQ_INTR);
958 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
959 __func__, td->td_proc->p_pid, td->td_name, it->it_need, td->td_state);
967 * Allow interrupt event binding for software interrupt handlers -- a no-op,
968 * since interrupts are generated in software rather than being directed by
972 swi_assign_cpu(void *arg, int cpu)
979 * Add a software interrupt handler to a specified event. If a given event
980 * is not specified, then a new event is created.
983 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
984 void *arg, int pri, enum intr_type flags, void **cookiep)
986 struct intr_event *ie;
989 if (flags & INTR_ENTROPY)
992 ie = (eventp != NULL) ? *eventp : NULL;
995 if (!(ie->ie_flags & IE_SOFT))
998 error = intr_event_create(&ie, NULL, IE_SOFT, 0,
999 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
1005 error = intr_event_add_handler(ie, name, NULL, handler, arg,
1006 PI_SWI(pri), flags, cookiep);
1011 * Schedule a software interrupt thread.
1014 swi_sched(void *cookie, int flags)
1016 struct intr_handler *ih = (struct intr_handler *)cookie;
1017 struct intr_event *ie = ih->ih_event;
1018 struct intr_entropy entropy;
1021 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
1024 entropy.event = (uintptr_t)ih;
1025 entropy.td = curthread;
1026 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI);
1029 * Set ih_need for this handler so that if the ithread is already
1030 * running it will execute this handler on the next pass. Otherwise,
1031 * it will execute it the next time it runs.
1035 if (!(flags & SWI_DELAY)) {
1037 error = intr_event_schedule_thread(ie);
1038 KASSERT(error == 0, ("stray software interrupt"));
1043 * Remove a software interrupt handler. Currently this code does not
1044 * remove the associated interrupt event if it becomes empty. Calling code
1045 * may do so manually via intr_event_destroy(), but that's not really
1046 * an optimal interface.
1049 swi_remove(void *cookie)
1052 return (intr_event_remove_handler(cookie));
1056 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
1058 struct intr_handler *ih, *ihn, *ihp;
1061 CK_SLIST_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
1063 * If this handler is marked for death, remove it from
1064 * the list of handlers and wake up the sleeper.
1066 if (ih->ih_flags & IH_DEAD) {
1067 mtx_lock(&ie->ie_lock);
1069 CK_SLIST_REMOVE_HEAD(&ie->ie_handlers, ih_next);
1071 CK_SLIST_REMOVE_AFTER(ihp, ih_next);
1072 ih->ih_flags &= ~IH_DEAD;
1074 mtx_unlock(&ie->ie_lock);
1079 * Now that we know that the current element won't be removed
1080 * update the previous element.
1084 if ((ih->ih_flags & IH_CHANGED) != 0) {
1085 mtx_lock(&ie->ie_lock);
1086 ih->ih_flags &= ~IH_CHANGED;
1088 mtx_unlock(&ie->ie_lock);
1091 /* Skip filter only handlers */
1092 if (ih->ih_handler == NULL)
1095 /* Skip suspended handlers */
1096 if ((ih->ih_flags & IH_SUSP) != 0)
1100 * For software interrupt threads, we only execute
1101 * handlers that have their need flag set. Hardware
1102 * interrupt threads always invoke all of their handlers.
1104 * ih_need can only be 0 or 1. Failed cmpset below
1105 * means that there is no request to execute handlers,
1106 * so a retry of the cmpset is not needed.
1108 if ((ie->ie_flags & IE_SOFT) != 0 &&
1109 atomic_cmpset_int(&ih->ih_need, 1, 0) == 0)
1112 /* Execute this handler. */
1113 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1114 __func__, p->p_pid, (void *)ih->ih_handler,
1115 ih->ih_argument, ih->ih_name, ih->ih_flags);
1117 if (!(ih->ih_flags & IH_MPSAFE))
1119 ih->ih_handler(ih->ih_argument);
1120 if (!(ih->ih_flags & IH_MPSAFE))
1126 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1129 /* Interrupt handlers should not sleep. */
1130 if (!(ie->ie_flags & IE_SOFT))
1131 THREAD_NO_SLEEPING();
1132 intr_event_execute_handlers(p, ie);
1133 if (!(ie->ie_flags & IE_SOFT))
1134 THREAD_SLEEPING_OK();
1137 * Interrupt storm handling:
1139 * If this interrupt source is currently storming, then throttle
1140 * it to only fire the handler once per clock tick.
1142 * If this interrupt source is not currently storming, but the
1143 * number of back to back interrupts exceeds the storm threshold,
1144 * then enter storming mode.
1146 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
1147 !(ie->ie_flags & IE_SOFT)) {
1148 /* Report the message only once every second. */
1149 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1151 "interrupt storm detected on \"%s\"; throttling interrupt source\n",
1159 * Now that all the handlers have had a chance to run, reenable
1160 * the interrupt source.
1162 if (ie->ie_post_ithread != NULL)
1163 ie->ie_post_ithread(ie->ie_source);
1167 * This is the main code for interrupt threads.
1170 ithread_loop(void *arg)
1172 struct intr_thread *ithd;
1173 struct intr_event *ie;
1180 ithd = (struct intr_thread *)arg;
1181 KASSERT(ithd->it_thread == td,
1182 ("%s: ithread and proc linkage out of sync", __func__));
1183 ie = ithd->it_event;
1188 * As long as we have interrupts outstanding, go through the
1189 * list of handlers, giving each one a go at it.
1193 * If we are an orphaned thread, then just die.
1195 if (ithd->it_flags & IT_DEAD) {
1196 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1197 p->p_pid, td->td_name);
1198 free(ithd, M_ITHREAD);
1203 * Service interrupts. If another interrupt arrives while
1204 * we are running, it will set it_need to note that we
1205 * should make another pass.
1207 * The load_acq part of the following cmpset ensures
1208 * that the load of ih_need in ithread_execute_handlers()
1209 * is ordered after the load of it_need here.
1211 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0)
1212 ithread_execute_handlers(p, ie);
1213 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1214 mtx_assert(&Giant, MA_NOTOWNED);
1217 * Processed all our interrupts. Now get the sched
1218 * lock. This may take a while and it_need may get
1219 * set again, so we have to check it again.
1222 if (atomic_load_acq_int(&ithd->it_need) == 0 &&
1223 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) {
1226 mi_switch(SW_VOL | SWT_IWAIT, NULL);
1228 if (ithd->it_flags & IT_WAIT) {
1230 ithd->it_flags &= ~IT_WAIT;
1241 * Main interrupt handling body.
1244 * o ie: the event connected to this interrupt.
1245 * o frame: some archs (i.e. i386) pass a frame to some.
1246 * handlers as their main argument.
1248 * o 0: everything ok.
1249 * o EINVAL: stray interrupt.
1252 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1254 struct intr_handler *ih;
1255 struct trapframe *oldframe;
1259 bool filter, thread;
1263 #ifdef KSTACK_USAGE_PROF
1264 intr_prof_stack_use(td, frame);
1267 /* An interrupt with no event or handlers is a stray interrupt. */
1268 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers))
1272 * Execute fast interrupt handlers directly.
1273 * To support clock handlers, if a handler registers
1274 * with a NULL argument, then we pass it a pointer to
1275 * a trapframe as its argument.
1277 td->td_intr_nesting_level++;
1282 oldframe = td->td_intr_frame;
1283 td->td_intr_frame = frame;
1285 phase = ie->ie_phase;
1286 atomic_add_int(&ie->ie_active[phase], 1);
1289 * This fence is required to ensure that no later loads are
1290 * re-ordered before the ie_active store.
1292 atomic_thread_fence_seq_cst();
1294 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
1295 if ((ih->ih_flags & IH_SUSP) != 0)
1297 if (ih->ih_filter == NULL) {
1301 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1302 ih->ih_filter, ih->ih_argument == NULL ? frame :
1303 ih->ih_argument, ih->ih_name);
1304 if (ih->ih_argument == NULL)
1305 ret = ih->ih_filter(frame);
1307 ret = ih->ih_filter(ih->ih_argument);
1308 KASSERT(ret == FILTER_STRAY ||
1309 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1310 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1311 ("%s: incorrect return value %#x from %s", __func__, ret,
1313 filter = filter || ret == FILTER_HANDLED;
1316 * Wrapper handler special handling:
1318 * in some particular cases (like pccard and pccbb),
1319 * the _real_ device handler is wrapped in a couple of
1320 * functions - a filter wrapper and an ithread wrapper.
1321 * In this case (and just in this case), the filter wrapper
1322 * could ask the system to schedule the ithread and mask
1323 * the interrupt source if the wrapped handler is composed
1324 * of just an ithread handler.
1326 * TODO: write a generic wrapper to avoid people rolling
1330 if (ret == FILTER_SCHEDULE_THREAD)
1334 atomic_add_rel_int(&ie->ie_active[phase], -1);
1336 td->td_intr_frame = oldframe;
1339 if (ie->ie_pre_ithread != NULL)
1340 ie->ie_pre_ithread(ie->ie_source);
1342 if (ie->ie_post_filter != NULL)
1343 ie->ie_post_filter(ie->ie_source);
1346 /* Schedule the ithread if needed. */
1350 error = intr_event_schedule_thread(ie);
1351 KASSERT(error == 0, ("bad stray interrupt"));
1354 td->td_intr_nesting_level--;
1356 /* The interrupt is not aknowledged by any filter and has no ithread. */
1357 if (!thread && !filter)
1365 * Dump details about an interrupt handler
1368 db_dump_intrhand(struct intr_handler *ih)
1372 db_printf("\t%-10s ", ih->ih_name);
1373 switch (ih->ih_pri) {
1393 if (ih->ih_pri >= PI_SOFT)
1396 db_printf("%4u", ih->ih_pri);
1400 if (ih->ih_filter != NULL) {
1402 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1404 if (ih->ih_handler != NULL) {
1405 if (ih->ih_filter != NULL)
1408 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1410 db_printf("(%p)", ih->ih_argument);
1412 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1416 if (ih->ih_flags & IH_EXCLUSIVE) {
1422 if (ih->ih_flags & IH_ENTROPY) {
1425 db_printf("ENTROPY");
1428 if (ih->ih_flags & IH_DEAD) {
1434 if (ih->ih_flags & IH_MPSAFE) {
1437 db_printf("MPSAFE");
1451 * Dump details about a event.
1454 db_dump_intr_event(struct intr_event *ie, int handlers)
1456 struct intr_handler *ih;
1457 struct intr_thread *it;
1460 db_printf("%s ", ie->ie_fullname);
1463 db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1465 db_printf("(no thread)");
1466 if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 ||
1467 (it != NULL && it->it_need)) {
1470 if (ie->ie_flags & IE_SOFT) {
1474 if (ie->ie_flags & IE_ENTROPY) {
1477 db_printf("ENTROPY");
1480 if (ie->ie_flags & IE_ADDING_THREAD) {
1483 db_printf("ADDING_THREAD");
1486 if (it != NULL && it->it_need) {
1496 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next)
1497 db_dump_intrhand(ih);
1501 * Dump data about interrupt handlers
1503 DB_SHOW_COMMAND(intr, db_show_intr)
1505 struct intr_event *ie;
1508 verbose = strchr(modif, 'v') != NULL;
1509 all = strchr(modif, 'a') != NULL;
1510 TAILQ_FOREACH(ie, &event_list, ie_list) {
1511 if (!all && CK_SLIST_EMPTY(&ie->ie_handlers))
1513 db_dump_intr_event(ie, verbose);
1521 * Start standard software interrupt threads
1524 start_softintr(void *dummy)
1527 if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
1528 panic("died while creating vm swi ithread");
1530 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1534 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1535 * The data for this machine dependent, and the declarations are in machine
1536 * dependent code. The layout of intrnames and intrcnt however is machine
1539 * We do not know the length of intrcnt and intrnames at compile time, so
1540 * calculate things at run time.
1543 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1545 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1548 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1549 NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1552 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1555 uint32_t *intrcnt32;
1559 if (req->flags & SCTL_MASK32) {
1561 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1562 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1563 if (intrcnt32 == NULL)
1565 for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1566 intrcnt32[i] = intrcnt[i];
1567 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1568 free(intrcnt32, M_TEMP);
1572 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1575 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1576 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");
1580 * DDB command to dump the interrupt statistics.
1582 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
1590 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1595 db_printf("%s\t%lu\n", cp, *i);
1596 cp += strlen(cp) + 1;