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/epoch.h>
52 #include <sys/random.h>
53 #include <sys/resourcevar.h>
54 #include <sys/sched.h>
56 #include <sys/sysctl.h>
57 #include <sys/syslog.h>
58 #include <sys/unistd.h>
59 #include <sys/vmmeter.h>
60 #include <machine/atomic.h>
61 #include <machine/cpu.h>
62 #include <machine/md_var.h>
63 #include <machine/stdarg.h>
66 #include <ddb/db_sym.h>
70 * Describe an interrupt thread. There is one of these per interrupt event.
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. */
79 /* Interrupt thread flags kept in it_flags */
80 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */
81 #define IT_WAIT 0x000002 /* Thread is waiting for completion. */
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 = 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 static TAILQ_HEAD(, intr_event) event_list =
102 TAILQ_HEAD_INITIALIZER(event_list);
103 static struct mtx event_lock;
104 MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF);
106 static void intr_event_update(struct intr_event *ie);
107 static int intr_event_schedule_thread(struct intr_event *ie);
108 static struct intr_thread *ithread_create(const char *name);
109 static void ithread_destroy(struct intr_thread *ithread);
110 static void ithread_execute_handlers(struct proc *p,
111 struct intr_event *ie);
112 static void ithread_loop(void *);
113 static void ithread_update(struct intr_thread *ithd);
114 static void start_softintr(void *);
116 /* Map an interrupt type to an ithread priority. */
118 intr_priority(enum intr_type flags)
122 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
123 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
144 pri = PI_DULL; /* don't care */
147 /* We didn't specify an interrupt level. */
148 panic("intr_priority: no interrupt type in flags");
155 * Update an ithread based on the associated intr_event.
158 ithread_update(struct intr_thread *ithd)
160 struct intr_event *ie;
165 td = ithd->it_thread;
166 mtx_assert(&ie->ie_lock, MA_OWNED);
168 /* Determine the overall priority of this event. */
169 if (CK_SLIST_EMPTY(&ie->ie_handlers))
172 pri = CK_SLIST_FIRST(&ie->ie_handlers)->ih_pri;
174 /* Update name and priority. */
175 strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
177 sched_clear_tdname(td);
185 * Regenerate the full name of an interrupt event and update its priority.
188 intr_event_update(struct intr_event *ie)
190 struct intr_handler *ih;
194 /* Start off with no entropy and just the name of the event. */
195 mtx_assert(&ie->ie_lock, MA_OWNED);
196 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
201 /* Run through all the handlers updating values. */
202 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
203 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
204 sizeof(ie->ie_fullname)) {
205 strcat(ie->ie_fullname, " ");
206 strcat(ie->ie_fullname, ih->ih_name);
210 ie->ie_hflags |= ih->ih_flags;
214 * If there is only one handler and its name is too long, just copy in
215 * as much of the end of the name (includes the unit number) as will
216 * fit. Otherwise, we have multiple handlers and not all of the names
217 * will fit. Add +'s to indicate missing names. If we run out of room
218 * and still have +'s to add, change the last character from a + to a *.
220 if (missed == 1 && space == 1) {
221 ih = CK_SLIST_FIRST(&ie->ie_handlers);
222 missed = strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 -
223 sizeof(ie->ie_fullname);
224 strcat(ie->ie_fullname, (missed == 0) ? " " : "-");
225 strcat(ie->ie_fullname, &ih->ih_name[missed]);
228 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
229 while (missed-- > 0) {
230 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
237 strcat(ie->ie_fullname, " +");
240 strcat(ie->ie_fullname, "+");
244 * If this event has an ithread, update it's priority and
247 if (ie->ie_thread != NULL)
248 ithread_update(ie->ie_thread);
249 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
253 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
254 void (*pre_ithread)(void *), void (*post_ithread)(void *),
255 void (*post_filter)(void *), int (*assign_cpu)(void *, int),
256 const char *fmt, ...)
258 struct intr_event *ie;
261 /* The only valid flag during creation is IE_SOFT. */
262 if ((flags & ~IE_SOFT) != 0)
264 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
265 ie->ie_source = source;
266 ie->ie_pre_ithread = pre_ithread;
267 ie->ie_post_ithread = post_ithread;
268 ie->ie_post_filter = post_filter;
269 ie->ie_assign_cpu = assign_cpu;
270 ie->ie_flags = flags;
273 CK_SLIST_INIT(&ie->ie_handlers);
274 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
277 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
279 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
280 mtx_lock(&event_lock);
281 TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
282 mtx_unlock(&event_lock);
285 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
290 * Bind an interrupt event to the specified CPU. Note that not all
291 * platforms support binding an interrupt to a CPU. For those
292 * platforms this request will fail. Using a cpu id of NOCPU unbinds
293 * the interrupt event.
296 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread)
301 /* Need a CPU to bind to. */
302 if (cpu != NOCPU && CPU_ABSENT(cpu))
305 if (ie->ie_assign_cpu == NULL)
308 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
313 * If we have any ithreads try to set their mask first to verify
317 mtx_lock(&ie->ie_lock);
318 if (ie->ie_thread != NULL) {
319 id = ie->ie_thread->it_thread->td_tid;
320 mtx_unlock(&ie->ie_lock);
321 error = cpuset_setithread(id, cpu);
325 mtx_unlock(&ie->ie_lock);
328 error = ie->ie_assign_cpu(ie->ie_source, cpu);
331 mtx_lock(&ie->ie_lock);
332 if (ie->ie_thread != NULL) {
334 id = ie->ie_thread->it_thread->td_tid;
335 mtx_unlock(&ie->ie_lock);
336 (void)cpuset_setithread(id, cpu);
338 mtx_unlock(&ie->ie_lock);
344 mtx_lock(&ie->ie_lock);
346 mtx_unlock(&ie->ie_lock);
353 * Bind an interrupt event to the specified CPU. For supported platforms, any
354 * associated ithreads as well as the primary interrupt context will be bound
355 * to the specificed CPU.
358 intr_event_bind(struct intr_event *ie, int cpu)
361 return (_intr_event_bind(ie, cpu, true, true));
365 * Bind an interrupt event to the specified CPU, but do not bind associated
369 intr_event_bind_irqonly(struct intr_event *ie, int cpu)
372 return (_intr_event_bind(ie, cpu, true, false));
376 * Bind an interrupt event's ithread to the specified CPU.
379 intr_event_bind_ithread(struct intr_event *ie, int cpu)
382 return (_intr_event_bind(ie, cpu, false, true));
386 * Bind an interrupt event's ithread to the specified cpuset.
389 intr_event_bind_ithread_cpuset(struct intr_event *ie, cpuset_t *cs)
393 mtx_lock(&ie->ie_lock);
394 if (ie->ie_thread != NULL) {
395 id = ie->ie_thread->it_thread->td_tid;
396 mtx_unlock(&ie->ie_lock);
397 return (cpuset_setthread(id, cs));
399 mtx_unlock(&ie->ie_lock);
404 static struct intr_event *
407 struct intr_event *ie;
409 mtx_lock(&event_lock);
410 TAILQ_FOREACH(ie, &event_list, ie_list)
411 if (ie->ie_irq == irq &&
412 (ie->ie_flags & IE_SOFT) == 0 &&
413 CK_SLIST_FIRST(&ie->ie_handlers) != NULL)
415 mtx_unlock(&event_lock);
420 intr_setaffinity(int irq, int mode, void *m)
422 struct intr_event *ie;
429 * If we're setting all cpus we can unbind. Otherwise make sure
430 * only one cpu is in the set.
432 if (CPU_CMP(cpuset_root, mask)) {
433 for (n = 0; n < CPU_SETSIZE; n++) {
434 if (!CPU_ISSET(n, mask))
441 ie = intr_lookup(irq);
446 return (intr_event_bind(ie, cpu));
447 case CPU_WHICH_INTRHANDLER:
448 return (intr_event_bind_irqonly(ie, cpu));
449 case CPU_WHICH_ITHREAD:
450 return (intr_event_bind_ithread(ie, cpu));
457 intr_getaffinity(int irq, int mode, void *m)
459 struct intr_event *ie;
467 ie = intr_lookup(irq);
475 case CPU_WHICH_INTRHANDLER:
476 mtx_lock(&ie->ie_lock);
477 if (ie->ie_cpu == NOCPU)
478 CPU_COPY(cpuset_root, mask);
480 CPU_SET(ie->ie_cpu, mask);
481 mtx_unlock(&ie->ie_lock);
483 case CPU_WHICH_ITHREAD:
484 mtx_lock(&ie->ie_lock);
485 if (ie->ie_thread == NULL) {
486 mtx_unlock(&ie->ie_lock);
487 CPU_COPY(cpuset_root, mask);
489 id = ie->ie_thread->it_thread->td_tid;
490 mtx_unlock(&ie->ie_lock);
491 error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL);
494 CPU_COPY(&td->td_cpuset->cs_mask, mask);
504 intr_event_destroy(struct intr_event *ie)
507 mtx_lock(&event_lock);
508 mtx_lock(&ie->ie_lock);
509 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
510 mtx_unlock(&ie->ie_lock);
511 mtx_unlock(&event_lock);
514 TAILQ_REMOVE(&event_list, ie, ie_list);
516 if (ie->ie_thread != NULL) {
517 ithread_destroy(ie->ie_thread);
518 ie->ie_thread = NULL;
521 mtx_unlock(&ie->ie_lock);
522 mtx_unlock(&event_lock);
523 mtx_destroy(&ie->ie_lock);
528 static struct intr_thread *
529 ithread_create(const char *name)
531 struct intr_thread *ithd;
535 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
537 error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
538 &td, RFSTOPPED | RFHIGHPID,
539 0, "intr", "%s", name);
541 panic("kproc_create() failed with %d", error);
543 sched_class(td, PRI_ITHD);
546 td->td_pflags |= TDP_ITHREAD;
547 ithd->it_thread = td;
548 CTR2(KTR_INTR, "%s: created %s", __func__, name);
553 ithread_destroy(struct intr_thread *ithread)
557 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
558 td = ithread->it_thread;
560 ithread->it_flags |= IT_DEAD;
561 if (TD_AWAITING_INTR(td)) {
563 sched_add(td, SRQ_INTR);
569 intr_event_add_handler(struct intr_event *ie, const char *name,
570 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
571 enum intr_type flags, void **cookiep)
573 struct intr_handler *ih, *temp_ih;
574 struct intr_handler **prevptr;
575 struct intr_thread *it;
577 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
580 /* Allocate and populate an interrupt handler structure. */
581 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
582 ih->ih_filter = filter;
583 ih->ih_handler = handler;
584 ih->ih_argument = arg;
585 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
588 if (flags & INTR_EXCL)
589 ih->ih_flags = IH_EXCLUSIVE;
590 if (flags & INTR_MPSAFE)
591 ih->ih_flags |= IH_MPSAFE;
592 if (flags & INTR_ENTROPY)
593 ih->ih_flags |= IH_ENTROPY;
594 if (flags & INTR_TYPE_NET)
595 ih->ih_flags |= IH_NET;
597 /* We can only have one exclusive handler in a event. */
598 mtx_lock(&ie->ie_lock);
599 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
600 if ((flags & INTR_EXCL) ||
601 (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
602 mtx_unlock(&ie->ie_lock);
608 /* Create a thread if we need one. */
609 while (ie->ie_thread == NULL && handler != NULL) {
610 if (ie->ie_flags & IE_ADDING_THREAD)
611 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
613 ie->ie_flags |= IE_ADDING_THREAD;
614 mtx_unlock(&ie->ie_lock);
615 it = ithread_create("intr: newborn");
616 mtx_lock(&ie->ie_lock);
617 ie->ie_flags &= ~IE_ADDING_THREAD;
625 /* Add the new handler to the event in priority order. */
626 CK_SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) {
627 if (temp_ih->ih_pri > ih->ih_pri)
630 CK_SLIST_INSERT_PREVPTR(prevptr, temp_ih, ih, ih_next);
632 intr_event_update(ie);
634 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
636 mtx_unlock(&ie->ie_lock);
644 * Append a description preceded by a ':' to the name of the specified
648 intr_event_describe_handler(struct intr_event *ie, void *cookie,
651 struct intr_handler *ih;
655 mtx_lock(&ie->ie_lock);
657 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
662 mtx_unlock(&ie->ie_lock);
663 panic("handler %p not found in interrupt event %p", cookie, ie);
669 * Look for an existing description by checking for an
670 * existing ":". This assumes device names do not include
671 * colons. If one is found, prepare to insert the new
672 * description at that point. If one is not found, find the
673 * end of the name to use as the insertion point.
675 start = strchr(ih->ih_name, ':');
677 start = strchr(ih->ih_name, 0);
680 * See if there is enough remaining room in the string for the
681 * description + ":". The "- 1" leaves room for the trailing
682 * '\0'. The "+ 1" accounts for the colon.
684 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
685 if (strlen(descr) + 1 > space) {
686 mtx_unlock(&ie->ie_lock);
690 /* Append a colon followed by the description. */
692 strcpy(start + 1, descr);
693 intr_event_update(ie);
694 mtx_unlock(&ie->ie_lock);
699 * Return the ie_source field from the intr_event an intr_handler is
703 intr_handler_source(void *cookie)
705 struct intr_handler *ih;
706 struct intr_event *ie;
708 ih = (struct intr_handler *)cookie;
713 ("interrupt handler \"%s\" has a NULL interrupt event",
715 return (ie->ie_source);
719 * If intr_event_handle() is running in the ISR context at the time of the call,
720 * then wait for it to complete.
723 intr_event_barrier(struct intr_event *ie)
727 mtx_assert(&ie->ie_lock, MA_OWNED);
728 phase = ie->ie_phase;
731 * Switch phase to direct future interrupts to the other active counter.
732 * Make sure that any preceding stores are visible before the switch.
734 KASSERT(ie->ie_active[!phase] == 0, ("idle phase has activity"));
735 atomic_store_rel_int(&ie->ie_phase, !phase);
738 * This code cooperates with wait-free iteration of ie_handlers
739 * in intr_event_handle.
740 * Make sure that the removal and the phase update are not reordered
741 * with the active count check.
742 * Note that no combination of acquire and release fences can provide
743 * that guarantee as Store->Load sequences can always be reordered.
745 atomic_thread_fence_seq_cst();
748 * Now wait on the inactive phase.
749 * The acquire fence is needed so that that all post-barrier accesses
750 * are after the check.
752 while (ie->ie_active[phase] > 0)
754 atomic_thread_fence_acq();
758 intr_handler_barrier(struct intr_handler *handler)
760 struct intr_event *ie;
762 ie = handler->ih_event;
763 mtx_assert(&ie->ie_lock, MA_OWNED);
764 KASSERT((handler->ih_flags & IH_DEAD) == 0,
765 ("update for a removed handler"));
767 if (ie->ie_thread == NULL) {
768 intr_event_barrier(ie);
771 if ((handler->ih_flags & IH_CHANGED) == 0) {
772 handler->ih_flags |= IH_CHANGED;
773 intr_event_schedule_thread(ie);
775 while ((handler->ih_flags & IH_CHANGED) != 0)
776 msleep(handler, &ie->ie_lock, 0, "ih_barr", 0);
780 * Sleep until an ithread finishes executing an interrupt handler.
782 * XXX Doesn't currently handle interrupt filters or fast interrupt
783 * handlers. This is intended for compatibility with linux drivers
784 * only. Do not use in BSD code.
789 struct intr_event *ie;
790 struct intr_thread *ithd;
793 ie = intr_lookup(irq);
796 if (ie->ie_thread == NULL)
798 ithd = ie->ie_thread;
799 td = ithd->it_thread;
801 * We set the flag and wait for it to be cleared to avoid
802 * long delays with potentially busy interrupt handlers
803 * were we to only sample TD_AWAITING_INTR() every tick.
806 if (!TD_AWAITING_INTR(td)) {
807 ithd->it_flags |= IT_WAIT;
808 while (ithd->it_flags & IT_WAIT) {
819 intr_event_remove_handler(void *cookie)
821 struct intr_handler *handler = (struct intr_handler *)cookie;
822 struct intr_event *ie;
823 struct intr_handler *ih;
824 struct intr_handler **prevptr;
831 ie = handler->ih_event;
833 ("interrupt handler \"%s\" has a NULL interrupt event",
836 mtx_lock(&ie->ie_lock);
837 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
839 CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
844 panic("interrupt handler \"%s\" not found in "
845 "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
849 * If there is no ithread, then directly remove the handler. Note that
850 * intr_event_handle() iterates ie_handlers in a lock-less fashion, so
851 * care needs to be taken to keep ie_handlers consistent and to free
852 * the removed handler only when ie_handlers is quiescent.
854 if (ie->ie_thread == NULL) {
855 CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
856 intr_event_barrier(ie);
857 intr_event_update(ie);
858 mtx_unlock(&ie->ie_lock);
859 free(handler, M_ITHREAD);
864 * Let the interrupt thread do the job.
865 * The interrupt source is disabled when the interrupt thread is
866 * running, so it does not have to worry about interaction with
867 * intr_event_handle().
869 KASSERT((handler->ih_flags & IH_DEAD) == 0,
870 ("duplicate handle remove"));
871 handler->ih_flags |= IH_DEAD;
872 intr_event_schedule_thread(ie);
873 while (handler->ih_flags & IH_DEAD)
874 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
875 intr_event_update(ie);
879 * XXX: This could be bad in the case of ppbus(8). Also, I think
880 * this could lead to races of stale data when servicing an
884 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
885 if (ih->ih_handler != NULL) {
891 ithread_destroy(ie->ie_thread);
892 ie->ie_thread = NULL;
895 mtx_unlock(&ie->ie_lock);
896 free(handler, M_ITHREAD);
901 intr_event_suspend_handler(void *cookie)
903 struct intr_handler *handler = (struct intr_handler *)cookie;
904 struct intr_event *ie;
908 ie = handler->ih_event;
910 ("interrupt handler \"%s\" has a NULL interrupt event",
912 mtx_lock(&ie->ie_lock);
913 handler->ih_flags |= IH_SUSP;
914 intr_handler_barrier(handler);
915 mtx_unlock(&ie->ie_lock);
920 intr_event_resume_handler(void *cookie)
922 struct intr_handler *handler = (struct intr_handler *)cookie;
923 struct intr_event *ie;
927 ie = handler->ih_event;
929 ("interrupt handler \"%s\" has a NULL interrupt event",
933 * intr_handler_barrier() acts not only as a barrier,
934 * it also allows to check for any pending interrupts.
936 mtx_lock(&ie->ie_lock);
937 handler->ih_flags &= ~IH_SUSP;
938 intr_handler_barrier(handler);
939 mtx_unlock(&ie->ie_lock);
944 intr_event_schedule_thread(struct intr_event *ie)
946 struct intr_entropy entropy;
947 struct intr_thread *it;
952 * If no ithread or no handlers, then we have a stray interrupt.
954 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers) ||
955 ie->ie_thread == NULL)
963 * If any of the handlers for this ithread claim to be good
964 * sources of entropy, then gather some.
966 if (ie->ie_hflags & IH_ENTROPY) {
967 entropy.event = (uintptr_t)ie;
969 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_INTERRUPT);
972 KASSERT(td->td_proc != NULL, ("ithread %s has no process", ie->ie_name));
975 * Set it_need to tell the thread to keep running if it is already
976 * running. Then, lock the thread and see if we actually need to
977 * put it on the runqueue.
979 * Use store_rel to arrange that the store to ih_need in
980 * swi_sched() is before the store to it_need and prepare for
981 * transfer of this order to loads in the ithread.
983 atomic_store_rel_int(&it->it_need, 1);
985 if (TD_AWAITING_INTR(td)) {
986 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid,
989 sched_add(td, SRQ_INTR);
991 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
992 __func__, td->td_proc->p_pid, td->td_name, it->it_need, td->td_state);
1000 * Allow interrupt event binding for software interrupt handlers -- a no-op,
1001 * since interrupts are generated in software rather than being directed by
1005 swi_assign_cpu(void *arg, int cpu)
1012 * Add a software interrupt handler to a specified event. If a given event
1013 * is not specified, then a new event is created.
1016 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
1017 void *arg, int pri, enum intr_type flags, void **cookiep)
1019 struct intr_event *ie;
1022 if (flags & INTR_ENTROPY)
1025 ie = (eventp != NULL) ? *eventp : NULL;
1028 if (!(ie->ie_flags & IE_SOFT))
1031 error = intr_event_create(&ie, NULL, IE_SOFT, 0,
1032 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
1038 error = intr_event_add_handler(ie, name, NULL, handler, arg,
1039 PI_SWI(pri), flags, cookiep);
1044 * Schedule a software interrupt thread.
1047 swi_sched(void *cookie, int flags)
1049 struct intr_handler *ih = (struct intr_handler *)cookie;
1050 struct intr_event *ie = ih->ih_event;
1051 struct intr_entropy entropy;
1054 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
1057 entropy.event = (uintptr_t)ih;
1058 entropy.td = curthread;
1059 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI);
1062 * Set ih_need for this handler so that if the ithread is already
1063 * running it will execute this handler on the next pass. Otherwise,
1064 * it will execute it the next time it runs.
1068 if (!(flags & SWI_DELAY)) {
1070 error = intr_event_schedule_thread(ie);
1071 KASSERT(error == 0, ("stray software interrupt"));
1076 * Remove a software interrupt handler. Currently this code does not
1077 * remove the associated interrupt event if it becomes empty. Calling code
1078 * may do so manually via intr_event_destroy(), but that's not really
1079 * an optimal interface.
1082 swi_remove(void *cookie)
1085 return (intr_event_remove_handler(cookie));
1089 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
1091 struct intr_handler *ih, *ihn, *ihp;
1094 CK_SLIST_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
1096 * If this handler is marked for death, remove it from
1097 * the list of handlers and wake up the sleeper.
1099 if (ih->ih_flags & IH_DEAD) {
1100 mtx_lock(&ie->ie_lock);
1102 CK_SLIST_REMOVE_HEAD(&ie->ie_handlers, ih_next);
1104 CK_SLIST_REMOVE_AFTER(ihp, ih_next);
1105 ih->ih_flags &= ~IH_DEAD;
1107 mtx_unlock(&ie->ie_lock);
1112 * Now that we know that the current element won't be removed
1113 * update the previous element.
1117 if ((ih->ih_flags & IH_CHANGED) != 0) {
1118 mtx_lock(&ie->ie_lock);
1119 ih->ih_flags &= ~IH_CHANGED;
1121 mtx_unlock(&ie->ie_lock);
1124 /* Skip filter only handlers */
1125 if (ih->ih_handler == NULL)
1128 /* Skip suspended handlers */
1129 if ((ih->ih_flags & IH_SUSP) != 0)
1133 * For software interrupt threads, we only execute
1134 * handlers that have their need flag set. Hardware
1135 * interrupt threads always invoke all of their handlers.
1137 * ih_need can only be 0 or 1. Failed cmpset below
1138 * means that there is no request to execute handlers,
1139 * so a retry of the cmpset is not needed.
1141 if ((ie->ie_flags & IE_SOFT) != 0 &&
1142 atomic_cmpset_int(&ih->ih_need, 1, 0) == 0)
1145 /* Execute this handler. */
1146 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1147 __func__, p->p_pid, (void *)ih->ih_handler,
1148 ih->ih_argument, ih->ih_name, ih->ih_flags);
1150 if (!(ih->ih_flags & IH_MPSAFE))
1152 ih->ih_handler(ih->ih_argument);
1153 if (!(ih->ih_flags & IH_MPSAFE))
1159 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1162 /* Interrupt handlers should not sleep. */
1163 if (!(ie->ie_flags & IE_SOFT))
1164 THREAD_NO_SLEEPING();
1165 intr_event_execute_handlers(p, ie);
1166 if (!(ie->ie_flags & IE_SOFT))
1167 THREAD_SLEEPING_OK();
1170 * Interrupt storm handling:
1172 * If this interrupt source is currently storming, then throttle
1173 * it to only fire the handler once per clock tick.
1175 * If this interrupt source is not currently storming, but the
1176 * number of back to back interrupts exceeds the storm threshold,
1177 * then enter storming mode.
1179 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
1180 !(ie->ie_flags & IE_SOFT)) {
1181 /* Report the message only once every second. */
1182 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1184 "interrupt storm detected on \"%s\"; throttling interrupt source\n",
1192 * Now that all the handlers have had a chance to run, reenable
1193 * the interrupt source.
1195 if (ie->ie_post_ithread != NULL)
1196 ie->ie_post_ithread(ie->ie_source);
1200 * This is the main code for interrupt threads.
1203 ithread_loop(void *arg)
1205 struct epoch_tracker et;
1206 struct intr_thread *ithd;
1207 struct intr_event *ie;
1210 int wake, epoch_count;
1214 ithd = (struct intr_thread *)arg;
1215 KASSERT(ithd->it_thread == td,
1216 ("%s: ithread and proc linkage out of sync", __func__));
1217 ie = ithd->it_event;
1222 * As long as we have interrupts outstanding, go through the
1223 * list of handlers, giving each one a go at it.
1227 * If we are an orphaned thread, then just die.
1229 if (ithd->it_flags & IT_DEAD) {
1230 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1231 p->p_pid, td->td_name);
1232 free(ithd, M_ITHREAD);
1237 * Service interrupts. If another interrupt arrives while
1238 * we are running, it will set it_need to note that we
1239 * should make another pass.
1241 * The load_acq part of the following cmpset ensures
1242 * that the load of ih_need in ithread_execute_handlers()
1243 * is ordered after the load of it_need here.
1245 if (ie->ie_hflags & IH_NET) {
1247 NET_EPOCH_ENTER(et);
1249 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) {
1250 ithread_execute_handlers(p, ie);
1251 if ((ie->ie_hflags & IH_NET) &&
1252 ++epoch_count >= intr_epoch_batch) {
1255 NET_EPOCH_ENTER(et);
1258 if (ie->ie_hflags & IH_NET)
1260 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1261 mtx_assert(&Giant, MA_NOTOWNED);
1264 * Processed all our interrupts. Now get the sched
1265 * lock. This may take a while and it_need may get
1266 * set again, so we have to check it again.
1269 if (atomic_load_acq_int(&ithd->it_need) == 0 &&
1270 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) {
1273 mi_switch(SW_VOL | SWT_IWAIT);
1275 if (ithd->it_flags & IT_WAIT) {
1277 ithd->it_flags &= ~IT_WAIT;
1289 * Main interrupt handling body.
1292 * o ie: the event connected to this interrupt.
1293 * o frame: some archs (i.e. i386) pass a frame to some.
1294 * handlers as their main argument.
1296 * o 0: everything ok.
1297 * o EINVAL: stray interrupt.
1300 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1302 struct intr_handler *ih;
1303 struct trapframe *oldframe;
1307 bool filter, thread;
1311 #ifdef KSTACK_USAGE_PROF
1312 intr_prof_stack_use(td, frame);
1315 /* An interrupt with no event or handlers is a stray interrupt. */
1316 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers))
1320 * Execute fast interrupt handlers directly.
1321 * To support clock handlers, if a handler registers
1322 * with a NULL argument, then we pass it a pointer to
1323 * a trapframe as its argument.
1325 td->td_intr_nesting_level++;
1330 oldframe = td->td_intr_frame;
1331 td->td_intr_frame = frame;
1333 phase = ie->ie_phase;
1334 atomic_add_int(&ie->ie_active[phase], 1);
1337 * This fence is required to ensure that no later loads are
1338 * re-ordered before the ie_active store.
1340 atomic_thread_fence_seq_cst();
1342 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
1343 if ((ih->ih_flags & IH_SUSP) != 0)
1345 if (ih->ih_filter == NULL) {
1349 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1350 ih->ih_filter, ih->ih_argument == NULL ? frame :
1351 ih->ih_argument, ih->ih_name);
1352 if (ih->ih_argument == NULL)
1353 ret = ih->ih_filter(frame);
1355 ret = ih->ih_filter(ih->ih_argument);
1356 KASSERT(ret == FILTER_STRAY ||
1357 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1358 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1359 ("%s: incorrect return value %#x from %s", __func__, ret,
1361 filter = filter || ret == FILTER_HANDLED;
1364 * Wrapper handler special handling:
1366 * in some particular cases (like pccard and pccbb),
1367 * the _real_ device handler is wrapped in a couple of
1368 * functions - a filter wrapper and an ithread wrapper.
1369 * In this case (and just in this case), the filter wrapper
1370 * could ask the system to schedule the ithread and mask
1371 * the interrupt source if the wrapped handler is composed
1372 * of just an ithread handler.
1374 * TODO: write a generic wrapper to avoid people rolling
1378 if (ret == FILTER_SCHEDULE_THREAD)
1382 atomic_add_rel_int(&ie->ie_active[phase], -1);
1384 td->td_intr_frame = oldframe;
1387 if (ie->ie_pre_ithread != NULL)
1388 ie->ie_pre_ithread(ie->ie_source);
1390 if (ie->ie_post_filter != NULL)
1391 ie->ie_post_filter(ie->ie_source);
1394 /* Schedule the ithread if needed. */
1398 error = intr_event_schedule_thread(ie);
1399 KASSERT(error == 0, ("bad stray interrupt"));
1402 td->td_intr_nesting_level--;
1404 /* The interrupt is not aknowledged by any filter and has no ithread. */
1405 if (!thread && !filter)
1413 * Dump details about an interrupt handler
1416 db_dump_intrhand(struct intr_handler *ih)
1420 db_printf("\t%-10s ", ih->ih_name);
1421 switch (ih->ih_pri) {
1441 if (ih->ih_pri >= PI_SOFT)
1444 db_printf("%4u", ih->ih_pri);
1448 if (ih->ih_filter != NULL) {
1450 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1452 if (ih->ih_handler != NULL) {
1453 if (ih->ih_filter != NULL)
1456 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1458 db_printf("(%p)", ih->ih_argument);
1460 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1464 if (ih->ih_flags & IH_EXCLUSIVE) {
1470 if (ih->ih_flags & IH_ENTROPY) {
1473 db_printf("ENTROPY");
1476 if (ih->ih_flags & IH_DEAD) {
1482 if (ih->ih_flags & IH_MPSAFE) {
1485 db_printf("MPSAFE");
1499 * Dump details about a event.
1502 db_dump_intr_event(struct intr_event *ie, int handlers)
1504 struct intr_handler *ih;
1505 struct intr_thread *it;
1508 db_printf("%s ", ie->ie_fullname);
1511 db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1513 db_printf("(no thread)");
1514 if ((ie->ie_flags & (IE_SOFT | IE_ADDING_THREAD)) != 0 ||
1515 (it != NULL && it->it_need)) {
1518 if (ie->ie_flags & IE_SOFT) {
1522 if (ie->ie_flags & IE_ADDING_THREAD) {
1525 db_printf("ADDING_THREAD");
1528 if (it != NULL && it->it_need) {
1538 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next)
1539 db_dump_intrhand(ih);
1543 * Dump data about interrupt handlers
1545 DB_SHOW_COMMAND(intr, db_show_intr)
1547 struct intr_event *ie;
1550 verbose = strchr(modif, 'v') != NULL;
1551 all = strchr(modif, 'a') != NULL;
1552 TAILQ_FOREACH(ie, &event_list, ie_list) {
1553 if (!all && CK_SLIST_EMPTY(&ie->ie_handlers))
1555 db_dump_intr_event(ie, verbose);
1563 * Start standard software interrupt threads
1566 start_softintr(void *dummy)
1569 if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
1570 panic("died while creating vm swi ithread");
1572 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1576 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1577 * The data for this machine dependent, and the declarations are in machine
1578 * dependent code. The layout of intrnames and intrcnt however is machine
1581 * We do not know the length of intrcnt and intrnames at compile time, so
1582 * calculate things at run time.
1585 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1587 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1590 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1591 NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1594 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1597 uint32_t *intrcnt32;
1601 if (req->flags & SCTL_MASK32) {
1603 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1604 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1605 if (intrcnt32 == NULL)
1607 for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1608 intrcnt32[i] = intrcnt[i];
1609 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1610 free(intrcnt32, M_TEMP);
1614 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1617 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1618 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");
1622 * DDB command to dump the interrupt statistics.
1624 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
1632 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1637 db_printf("%s\t%lu\n", cp, *i);
1638 cp += strlen(cp) + 1;