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/smp.h>
64 #include <machine/stdarg.h>
67 #include <ddb/db_sym.h>
71 * Describe an interrupt thread. There is one of these per interrupt event.
74 struct intr_event *it_event;
75 struct thread *it_thread; /* Kernel thread. */
76 int it_flags; /* (j) IT_* flags. */
77 int it_need; /* Needs service. */
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. */
89 struct intr_event *clk_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;
192 int missed, space, flags;
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 flags |= ih->ih_flags;
212 ie->ie_hflags = flags;
215 * If there is only one handler and its name is too long, just copy in
216 * as much of the end of the name (includes the unit number) as will
217 * fit. Otherwise, we have multiple handlers and not all of the names
218 * will fit. Add +'s to indicate missing names. If we run out of room
219 * and still have +'s to add, change the last character from a + to a *.
221 if (missed == 1 && space == 1) {
222 ih = CK_SLIST_FIRST(&ie->ie_handlers);
223 missed = strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 -
224 sizeof(ie->ie_fullname);
225 strcat(ie->ie_fullname, (missed == 0) ? " " : "-");
226 strcat(ie->ie_fullname, &ih->ih_name[missed]);
229 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
230 while (missed-- > 0) {
231 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
238 strcat(ie->ie_fullname, " +");
241 strcat(ie->ie_fullname, "+");
245 * If this event has an ithread, update it's priority and
248 if (ie->ie_thread != NULL)
249 ithread_update(ie->ie_thread);
250 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
254 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
255 void (*pre_ithread)(void *), void (*post_ithread)(void *),
256 void (*post_filter)(void *), int (*assign_cpu)(void *, int),
257 const char *fmt, ...)
259 struct intr_event *ie;
262 /* The only valid flag during creation is IE_SOFT. */
263 if ((flags & ~IE_SOFT) != 0)
265 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
266 ie->ie_source = source;
267 ie->ie_pre_ithread = pre_ithread;
268 ie->ie_post_ithread = post_ithread;
269 ie->ie_post_filter = post_filter;
270 ie->ie_assign_cpu = assign_cpu;
271 ie->ie_flags = flags;
274 CK_SLIST_INIT(&ie->ie_handlers);
275 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
278 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
280 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
281 mtx_lock(&event_lock);
282 TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
283 mtx_unlock(&event_lock);
286 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
291 * Bind an interrupt event to the specified CPU. Note that not all
292 * platforms support binding an interrupt to a CPU. For those
293 * platforms this request will fail. Using a cpu id of NOCPU unbinds
294 * the interrupt event.
297 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread)
302 /* Need a CPU to bind to. */
303 if (cpu != NOCPU && CPU_ABSENT(cpu))
306 if (ie->ie_assign_cpu == NULL)
309 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
314 * If we have any ithreads try to set their mask first to verify
318 mtx_lock(&ie->ie_lock);
319 if (ie->ie_thread != NULL) {
320 id = ie->ie_thread->it_thread->td_tid;
321 mtx_unlock(&ie->ie_lock);
322 error = cpuset_setithread(id, cpu);
326 mtx_unlock(&ie->ie_lock);
329 error = ie->ie_assign_cpu(ie->ie_source, cpu);
332 mtx_lock(&ie->ie_lock);
333 if (ie->ie_thread != NULL) {
335 id = ie->ie_thread->it_thread->td_tid;
336 mtx_unlock(&ie->ie_lock);
337 (void)cpuset_setithread(id, cpu);
339 mtx_unlock(&ie->ie_lock);
345 mtx_lock(&ie->ie_lock);
347 mtx_unlock(&ie->ie_lock);
354 * Bind an interrupt event to the specified CPU. For supported platforms, any
355 * associated ithreads as well as the primary interrupt context will be bound
356 * to the specificed CPU.
359 intr_event_bind(struct intr_event *ie, int cpu)
362 return (_intr_event_bind(ie, cpu, true, true));
366 * Bind an interrupt event to the specified CPU, but do not bind associated
370 intr_event_bind_irqonly(struct intr_event *ie, int cpu)
373 return (_intr_event_bind(ie, cpu, true, false));
377 * Bind an interrupt event's ithread to the specified CPU.
380 intr_event_bind_ithread(struct intr_event *ie, int cpu)
383 return (_intr_event_bind(ie, cpu, false, true));
387 * Bind an interrupt event's ithread to the specified cpuset.
390 intr_event_bind_ithread_cpuset(struct intr_event *ie, cpuset_t *cs)
394 mtx_lock(&ie->ie_lock);
395 if (ie->ie_thread != NULL) {
396 id = ie->ie_thread->it_thread->td_tid;
397 mtx_unlock(&ie->ie_lock);
398 return (cpuset_setthread(id, cs));
400 mtx_unlock(&ie->ie_lock);
405 static struct intr_event *
408 struct intr_event *ie;
410 mtx_lock(&event_lock);
411 TAILQ_FOREACH(ie, &event_list, ie_list)
412 if (ie->ie_irq == irq &&
413 (ie->ie_flags & IE_SOFT) == 0 &&
414 CK_SLIST_FIRST(&ie->ie_handlers) != NULL)
416 mtx_unlock(&event_lock);
421 intr_setaffinity(int irq, int mode, void *m)
423 struct intr_event *ie;
430 * If we're setting all cpus we can unbind. Otherwise make sure
431 * only one cpu is in the set.
433 if (CPU_CMP(cpuset_root, mask)) {
434 for (n = 0; n < CPU_SETSIZE; n++) {
435 if (!CPU_ISSET(n, mask))
442 ie = intr_lookup(irq);
447 return (intr_event_bind(ie, cpu));
448 case CPU_WHICH_INTRHANDLER:
449 return (intr_event_bind_irqonly(ie, cpu));
450 case CPU_WHICH_ITHREAD:
451 return (intr_event_bind_ithread(ie, cpu));
458 intr_getaffinity(int irq, int mode, void *m)
460 struct intr_event *ie;
468 ie = intr_lookup(irq);
476 case CPU_WHICH_INTRHANDLER:
477 mtx_lock(&ie->ie_lock);
478 if (ie->ie_cpu == NOCPU)
479 CPU_COPY(cpuset_root, mask);
481 CPU_SET(ie->ie_cpu, mask);
482 mtx_unlock(&ie->ie_lock);
484 case CPU_WHICH_ITHREAD:
485 mtx_lock(&ie->ie_lock);
486 if (ie->ie_thread == NULL) {
487 mtx_unlock(&ie->ie_lock);
488 CPU_COPY(cpuset_root, mask);
490 id = ie->ie_thread->it_thread->td_tid;
491 mtx_unlock(&ie->ie_lock);
492 error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL);
495 CPU_COPY(&td->td_cpuset->cs_mask, mask);
505 intr_event_destroy(struct intr_event *ie)
511 mtx_lock(&event_lock);
512 mtx_lock(&ie->ie_lock);
513 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
514 mtx_unlock(&ie->ie_lock);
515 mtx_unlock(&event_lock);
518 TAILQ_REMOVE(&event_list, ie, ie_list);
520 if (ie->ie_thread != NULL) {
521 ithread_destroy(ie->ie_thread);
522 ie->ie_thread = NULL;
525 mtx_unlock(&ie->ie_lock);
526 mtx_unlock(&event_lock);
527 mtx_destroy(&ie->ie_lock);
532 static struct intr_thread *
533 ithread_create(const char *name)
535 struct intr_thread *ithd;
539 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
541 error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
542 &td, RFSTOPPED | RFHIGHPID,
543 0, "intr", "%s", name);
545 panic("kproc_create() failed with %d", error);
547 sched_class(td, PRI_ITHD);
550 td->td_pflags |= TDP_ITHREAD;
551 ithd->it_thread = td;
552 CTR2(KTR_INTR, "%s: created %s", __func__, name);
557 ithread_destroy(struct intr_thread *ithread)
561 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
562 td = ithread->it_thread;
564 ithread->it_flags |= IT_DEAD;
565 if (TD_AWAITING_INTR(td)) {
567 sched_add(td, SRQ_INTR);
573 intr_event_add_handler(struct intr_event *ie, const char *name,
574 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
575 enum intr_type flags, void **cookiep)
577 struct intr_handler *ih, *temp_ih;
578 struct intr_handler **prevptr;
579 struct intr_thread *it;
581 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
584 /* Allocate and populate an interrupt handler structure. */
585 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
586 ih->ih_filter = filter;
587 ih->ih_handler = handler;
588 ih->ih_argument = arg;
589 strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
592 if (flags & INTR_EXCL)
593 ih->ih_flags = IH_EXCLUSIVE;
594 if (flags & INTR_MPSAFE)
595 ih->ih_flags |= IH_MPSAFE;
596 if (flags & INTR_ENTROPY)
597 ih->ih_flags |= IH_ENTROPY;
598 if (flags & INTR_TYPE_NET)
599 ih->ih_flags |= IH_NET;
601 /* We can only have one exclusive handler in a event. */
602 mtx_lock(&ie->ie_lock);
603 if (!CK_SLIST_EMPTY(&ie->ie_handlers)) {
604 if ((flags & INTR_EXCL) ||
605 (CK_SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
606 mtx_unlock(&ie->ie_lock);
612 /* Create a thread if we need one. */
613 while (ie->ie_thread == NULL && handler != NULL) {
614 if (ie->ie_flags & IE_ADDING_THREAD)
615 msleep(ie, &ie->ie_lock, 0, "ithread", 0);
617 ie->ie_flags |= IE_ADDING_THREAD;
618 mtx_unlock(&ie->ie_lock);
619 it = ithread_create("intr: newborn");
620 mtx_lock(&ie->ie_lock);
621 ie->ie_flags &= ~IE_ADDING_THREAD;
629 /* Add the new handler to the event in priority order. */
630 CK_SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) {
631 if (temp_ih->ih_pri > ih->ih_pri)
634 CK_SLIST_INSERT_PREVPTR(prevptr, temp_ih, ih, ih_next);
636 intr_event_update(ie);
638 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
640 mtx_unlock(&ie->ie_lock);
648 * Append a description preceded by a ':' to the name of the specified
652 intr_event_describe_handler(struct intr_event *ie, void *cookie,
655 struct intr_handler *ih;
659 mtx_lock(&ie->ie_lock);
661 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
666 mtx_unlock(&ie->ie_lock);
667 panic("handler %p not found in interrupt event %p", cookie, ie);
673 * Look for an existing description by checking for an
674 * existing ":". This assumes device names do not include
675 * colons. If one is found, prepare to insert the new
676 * description at that point. If one is not found, find the
677 * end of the name to use as the insertion point.
679 start = strchr(ih->ih_name, ':');
681 start = strchr(ih->ih_name, 0);
684 * See if there is enough remaining room in the string for the
685 * description + ":". The "- 1" leaves room for the trailing
686 * '\0'. The "+ 1" accounts for the colon.
688 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
689 if (strlen(descr) + 1 > space) {
690 mtx_unlock(&ie->ie_lock);
694 /* Append a colon followed by the description. */
696 strcpy(start + 1, descr);
697 intr_event_update(ie);
698 mtx_unlock(&ie->ie_lock);
703 * Return the ie_source field from the intr_event an intr_handler is
707 intr_handler_source(void *cookie)
709 struct intr_handler *ih;
710 struct intr_event *ie;
712 ih = (struct intr_handler *)cookie;
717 ("interrupt handler \"%s\" has a NULL interrupt event",
719 return (ie->ie_source);
723 * If intr_event_handle() is running in the ISR context at the time of the call,
724 * then wait for it to complete.
727 intr_event_barrier(struct intr_event *ie)
731 mtx_assert(&ie->ie_lock, MA_OWNED);
732 phase = ie->ie_phase;
735 * Switch phase to direct future interrupts to the other active counter.
736 * Make sure that any preceding stores are visible before the switch.
738 KASSERT(ie->ie_active[!phase] == 0, ("idle phase has activity"));
739 atomic_store_rel_int(&ie->ie_phase, !phase);
742 * This code cooperates with wait-free iteration of ie_handlers
743 * in intr_event_handle.
744 * Make sure that the removal and the phase update are not reordered
745 * with the active count check.
746 * Note that no combination of acquire and release fences can provide
747 * that guarantee as Store->Load sequences can always be reordered.
749 atomic_thread_fence_seq_cst();
752 * Now wait on the inactive phase.
753 * The acquire fence is needed so that all post-barrier accesses
754 * are after the check.
756 while (ie->ie_active[phase] > 0)
758 atomic_thread_fence_acq();
762 intr_handler_barrier(struct intr_handler *handler)
764 struct intr_event *ie;
766 ie = handler->ih_event;
767 mtx_assert(&ie->ie_lock, MA_OWNED);
768 KASSERT((handler->ih_flags & IH_DEAD) == 0,
769 ("update for a removed handler"));
771 if (ie->ie_thread == NULL) {
772 intr_event_barrier(ie);
775 if ((handler->ih_flags & IH_CHANGED) == 0) {
776 handler->ih_flags |= IH_CHANGED;
777 intr_event_schedule_thread(ie);
779 while ((handler->ih_flags & IH_CHANGED) != 0)
780 msleep(handler, &ie->ie_lock, 0, "ih_barr", 0);
784 * Sleep until an ithread finishes executing an interrupt handler.
786 * XXX Doesn't currently handle interrupt filters or fast interrupt
787 * handlers. This is intended for LinuxKPI drivers only.
788 * Do not use in BSD code.
793 struct intr_event *ie;
794 struct intr_thread *ithd;
797 ie = intr_lookup(irq);
800 if (ie->ie_thread == NULL)
802 ithd = ie->ie_thread;
803 td = ithd->it_thread;
805 * We set the flag and wait for it to be cleared to avoid
806 * long delays with potentially busy interrupt handlers
807 * were we to only sample TD_AWAITING_INTR() every tick.
810 if (!TD_AWAITING_INTR(td)) {
811 ithd->it_flags |= IT_WAIT;
812 while (ithd->it_flags & IT_WAIT) {
823 intr_event_remove_handler(void *cookie)
825 struct intr_handler *handler = (struct intr_handler *)cookie;
826 struct intr_event *ie;
827 struct intr_handler *ih;
828 struct intr_handler **prevptr;
835 ie = handler->ih_event;
837 ("interrupt handler \"%s\" has a NULL interrupt event",
840 mtx_lock(&ie->ie_lock);
841 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
843 CK_SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
848 panic("interrupt handler \"%s\" not found in "
849 "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
853 * If there is no ithread, then directly remove the handler. Note that
854 * intr_event_handle() iterates ie_handlers in a lock-less fashion, so
855 * care needs to be taken to keep ie_handlers consistent and to free
856 * the removed handler only when ie_handlers is quiescent.
858 if (ie->ie_thread == NULL) {
859 CK_SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
860 intr_event_barrier(ie);
861 intr_event_update(ie);
862 mtx_unlock(&ie->ie_lock);
863 free(handler, M_ITHREAD);
868 * Let the interrupt thread do the job.
869 * The interrupt source is disabled when the interrupt thread is
870 * running, so it does not have to worry about interaction with
871 * intr_event_handle().
873 KASSERT((handler->ih_flags & IH_DEAD) == 0,
874 ("duplicate handle remove"));
875 handler->ih_flags |= IH_DEAD;
876 intr_event_schedule_thread(ie);
877 while (handler->ih_flags & IH_DEAD)
878 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
879 intr_event_update(ie);
883 * XXX: This could be bad in the case of ppbus(8). Also, I think
884 * this could lead to races of stale data when servicing an
888 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
889 if (ih->ih_handler != NULL) {
895 ithread_destroy(ie->ie_thread);
896 ie->ie_thread = NULL;
899 mtx_unlock(&ie->ie_lock);
900 free(handler, M_ITHREAD);
905 intr_event_suspend_handler(void *cookie)
907 struct intr_handler *handler = (struct intr_handler *)cookie;
908 struct intr_event *ie;
912 ie = handler->ih_event;
914 ("interrupt handler \"%s\" has a NULL interrupt event",
916 mtx_lock(&ie->ie_lock);
917 handler->ih_flags |= IH_SUSP;
918 intr_handler_barrier(handler);
919 mtx_unlock(&ie->ie_lock);
924 intr_event_resume_handler(void *cookie)
926 struct intr_handler *handler = (struct intr_handler *)cookie;
927 struct intr_event *ie;
931 ie = handler->ih_event;
933 ("interrupt handler \"%s\" has a NULL interrupt event",
937 * intr_handler_barrier() acts not only as a barrier,
938 * it also allows to check for any pending interrupts.
940 mtx_lock(&ie->ie_lock);
941 handler->ih_flags &= ~IH_SUSP;
942 intr_handler_barrier(handler);
943 mtx_unlock(&ie->ie_lock);
948 intr_event_schedule_thread(struct intr_event *ie)
950 struct intr_entropy entropy;
951 struct intr_thread *it;
956 * If no ithread or no handlers, then we have a stray interrupt.
958 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers) ||
959 ie->ie_thread == NULL)
967 * If any of the handlers for this ithread claim to be good
968 * sources of entropy, then gather some.
970 if (ie->ie_hflags & IH_ENTROPY) {
971 entropy.event = (uintptr_t)ie;
973 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_INTERRUPT);
976 KASSERT(td->td_proc != NULL, ("ithread %s has no process", ie->ie_name));
979 * Set it_need to tell the thread to keep running if it is already
980 * running. Then, lock the thread and see if we actually need to
981 * put it on the runqueue.
983 * Use store_rel to arrange that the store to ih_need in
984 * swi_sched() is before the store to it_need and prepare for
985 * transfer of this order to loads in the ithread.
987 atomic_store_rel_int(&it->it_need, 1);
989 if (TD_AWAITING_INTR(td)) {
990 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid,
993 sched_add(td, SRQ_INTR);
995 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
996 __func__, td->td_proc->p_pid, td->td_name, it->it_need, td->td_state);
1004 * Allow interrupt event binding for software interrupt handlers -- a no-op,
1005 * since interrupts are generated in software rather than being directed by
1009 swi_assign_cpu(void *arg, int cpu)
1016 * Add a software interrupt handler to a specified event. If a given event
1017 * is not specified, then a new event is created.
1020 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
1021 void *arg, int pri, enum intr_type flags, void **cookiep)
1023 struct intr_event *ie;
1026 if (flags & INTR_ENTROPY)
1029 ie = (eventp != NULL) ? *eventp : NULL;
1032 if (!(ie->ie_flags & IE_SOFT))
1035 error = intr_event_create(&ie, NULL, IE_SOFT, 0,
1036 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
1042 if (handler != NULL) {
1043 error = intr_event_add_handler(ie, name, NULL, handler, arg,
1044 PI_SWI(pri), flags, cookiep);
1050 * Schedule a software interrupt thread.
1053 swi_sched(void *cookie, int flags)
1055 struct intr_handler *ih = (struct intr_handler *)cookie;
1056 struct intr_event *ie = ih->ih_event;
1057 struct intr_entropy entropy;
1060 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
1063 if ((flags & SWI_FROMNMI) == 0) {
1064 entropy.event = (uintptr_t)ih;
1065 entropy.td = curthread;
1066 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_SWI);
1070 * Set ih_need for this handler so that if the ithread is already
1071 * running it will execute this handler on the next pass. Otherwise,
1072 * it will execute it the next time it runs.
1076 if (flags & SWI_DELAY)
1079 if (flags & SWI_FROMNMI) {
1080 #if defined(SMP) && (defined(__i386__) || defined(__amd64__))
1081 KASSERT(ie == clk_intr_event,
1082 ("SWI_FROMNMI used not with clk_intr_event"));
1083 ipi_self_from_nmi(IPI_SWI);
1087 error = intr_event_schedule_thread(ie);
1088 KASSERT(error == 0, ("stray software interrupt"));
1093 * Remove a software interrupt handler. Currently this code does not
1094 * remove the associated interrupt event if it becomes empty. Calling code
1095 * may do so manually via intr_event_destroy(), but that's not really
1096 * an optimal interface.
1099 swi_remove(void *cookie)
1102 return (intr_event_remove_handler(cookie));
1106 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
1108 struct intr_handler *ih, *ihn, *ihp;
1111 CK_SLIST_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
1113 * If this handler is marked for death, remove it from
1114 * the list of handlers and wake up the sleeper.
1116 if (ih->ih_flags & IH_DEAD) {
1117 mtx_lock(&ie->ie_lock);
1119 CK_SLIST_REMOVE_HEAD(&ie->ie_handlers, ih_next);
1121 CK_SLIST_REMOVE_AFTER(ihp, ih_next);
1122 ih->ih_flags &= ~IH_DEAD;
1124 mtx_unlock(&ie->ie_lock);
1129 * Now that we know that the current element won't be removed
1130 * update the previous element.
1134 if ((ih->ih_flags & IH_CHANGED) != 0) {
1135 mtx_lock(&ie->ie_lock);
1136 ih->ih_flags &= ~IH_CHANGED;
1138 mtx_unlock(&ie->ie_lock);
1141 /* Skip filter only handlers */
1142 if (ih->ih_handler == NULL)
1145 /* Skip suspended handlers */
1146 if ((ih->ih_flags & IH_SUSP) != 0)
1150 * For software interrupt threads, we only execute
1151 * handlers that have their need flag set. Hardware
1152 * interrupt threads always invoke all of their handlers.
1154 * ih_need can only be 0 or 1. Failed cmpset below
1155 * means that there is no request to execute handlers,
1156 * so a retry of the cmpset is not needed.
1158 if ((ie->ie_flags & IE_SOFT) != 0 &&
1159 atomic_cmpset_int(&ih->ih_need, 1, 0) == 0)
1162 /* Execute this handler. */
1163 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1164 __func__, p->p_pid, (void *)ih->ih_handler,
1165 ih->ih_argument, ih->ih_name, ih->ih_flags);
1167 if (!(ih->ih_flags & IH_MPSAFE))
1169 ih->ih_handler(ih->ih_argument);
1170 if (!(ih->ih_flags & IH_MPSAFE))
1176 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1179 /* Interrupt handlers should not sleep. */
1180 if (!(ie->ie_flags & IE_SOFT))
1181 THREAD_NO_SLEEPING();
1182 intr_event_execute_handlers(p, ie);
1183 if (!(ie->ie_flags & IE_SOFT))
1184 THREAD_SLEEPING_OK();
1187 * Interrupt storm handling:
1189 * If this interrupt source is currently storming, then throttle
1190 * it to only fire the handler once per clock tick.
1192 * If this interrupt source is not currently storming, but the
1193 * number of back to back interrupts exceeds the storm threshold,
1194 * then enter storming mode.
1196 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
1197 !(ie->ie_flags & IE_SOFT)) {
1198 /* Report the message only once every second. */
1199 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1201 "interrupt storm detected on \"%s\"; throttling interrupt source\n",
1209 * Now that all the handlers have had a chance to run, reenable
1210 * the interrupt source.
1212 if (ie->ie_post_ithread != NULL)
1213 ie->ie_post_ithread(ie->ie_source);
1217 * This is the main code for interrupt threads.
1220 ithread_loop(void *arg)
1222 struct epoch_tracker et;
1223 struct intr_thread *ithd;
1224 struct intr_event *ie;
1227 int wake, epoch_count;
1232 ithd = (struct intr_thread *)arg;
1233 KASSERT(ithd->it_thread == td,
1234 ("%s: ithread and proc linkage out of sync", __func__));
1235 ie = ithd->it_event;
1240 * As long as we have interrupts outstanding, go through the
1241 * list of handlers, giving each one a go at it.
1245 * If we are an orphaned thread, then just die.
1247 if (ithd->it_flags & IT_DEAD) {
1248 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1249 p->p_pid, td->td_name);
1250 free(ithd, M_ITHREAD);
1255 * Service interrupts. If another interrupt arrives while
1256 * we are running, it will set it_need to note that we
1257 * should make another pass.
1259 * The load_acq part of the following cmpset ensures
1260 * that the load of ih_need in ithread_execute_handlers()
1261 * is ordered after the load of it_need here.
1264 (atomic_load_int(&ie->ie_hflags) & IH_NET) != 0;
1267 NET_EPOCH_ENTER(et);
1269 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) {
1270 ithread_execute_handlers(p, ie);
1272 ++epoch_count >= intr_epoch_batch) {
1275 NET_EPOCH_ENTER(et);
1280 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1281 mtx_assert(&Giant, MA_NOTOWNED);
1284 * Processed all our interrupts. Now get the sched
1285 * lock. This may take a while and it_need may get
1286 * set again, so we have to check it again.
1289 if (atomic_load_acq_int(&ithd->it_need) == 0 &&
1290 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) {
1293 mi_switch(SW_VOL | SWT_IWAIT);
1295 if (ithd->it_flags & IT_WAIT) {
1297 ithd->it_flags &= ~IT_WAIT;
1309 * Main interrupt handling body.
1312 * o ie: the event connected to this interrupt.
1313 * o frame: some archs (i.e. i386) pass a frame to some.
1314 * handlers as their main argument.
1316 * o 0: everything ok.
1317 * o EINVAL: stray interrupt.
1320 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1322 struct intr_handler *ih;
1323 struct trapframe *oldframe;
1327 bool filter, thread;
1331 #ifdef KSTACK_USAGE_PROF
1332 intr_prof_stack_use(td, frame);
1335 /* An interrupt with no event or handlers is a stray interrupt. */
1336 if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers))
1340 * Execute fast interrupt handlers directly.
1341 * To support clock handlers, if a handler registers
1342 * with a NULL argument, then we pass it a pointer to
1343 * a trapframe as its argument.
1345 td->td_intr_nesting_level++;
1350 oldframe = td->td_intr_frame;
1351 td->td_intr_frame = frame;
1353 phase = ie->ie_phase;
1354 atomic_add_int(&ie->ie_active[phase], 1);
1357 * This fence is required to ensure that no later loads are
1358 * re-ordered before the ie_active store.
1360 atomic_thread_fence_seq_cst();
1362 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
1363 if ((ih->ih_flags & IH_SUSP) != 0)
1365 if ((ie->ie_flags & IE_SOFT) != 0 && ih->ih_need == 0)
1367 if (ih->ih_filter == NULL) {
1371 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1372 ih->ih_filter, ih->ih_argument == NULL ? frame :
1373 ih->ih_argument, ih->ih_name);
1374 if (ih->ih_argument == NULL)
1375 ret = ih->ih_filter(frame);
1377 ret = ih->ih_filter(ih->ih_argument);
1378 KASSERT(ret == FILTER_STRAY ||
1379 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1380 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1381 ("%s: incorrect return value %#x from %s", __func__, ret,
1383 filter = filter || ret == FILTER_HANDLED;
1386 * Wrapper handler special handling:
1388 * in some particular cases (like pccard and pccbb),
1389 * the _real_ device handler is wrapped in a couple of
1390 * functions - a filter wrapper and an ithread wrapper.
1391 * In this case (and just in this case), the filter wrapper
1392 * could ask the system to schedule the ithread and mask
1393 * the interrupt source if the wrapped handler is composed
1394 * of just an ithread handler.
1396 * TODO: write a generic wrapper to avoid people rolling
1400 if (ret == FILTER_SCHEDULE_THREAD)
1404 atomic_add_rel_int(&ie->ie_active[phase], -1);
1406 td->td_intr_frame = oldframe;
1409 if (ie->ie_pre_ithread != NULL)
1410 ie->ie_pre_ithread(ie->ie_source);
1412 if (ie->ie_post_filter != NULL)
1413 ie->ie_post_filter(ie->ie_source);
1416 /* Schedule the ithread if needed. */
1420 error = intr_event_schedule_thread(ie);
1421 KASSERT(error == 0, ("bad stray interrupt"));
1424 td->td_intr_nesting_level--;
1426 /* The interrupt is not aknowledged by any filter and has no ithread. */
1427 if (!thread && !filter)
1435 * Dump details about an interrupt handler
1438 db_dump_intrhand(struct intr_handler *ih)
1442 db_printf("\t%-10s ", ih->ih_name);
1443 switch (ih->ih_pri) {
1463 if (ih->ih_pri >= PI_SOFT)
1466 db_printf("%4u", ih->ih_pri);
1470 if (ih->ih_filter != NULL) {
1472 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1474 if (ih->ih_handler != NULL) {
1475 if (ih->ih_filter != NULL)
1478 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1480 db_printf("(%p)", ih->ih_argument);
1482 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1486 if (ih->ih_flags & IH_EXCLUSIVE) {
1492 if (ih->ih_flags & IH_ENTROPY) {
1495 db_printf("ENTROPY");
1498 if (ih->ih_flags & IH_DEAD) {
1504 if (ih->ih_flags & IH_MPSAFE) {
1507 db_printf("MPSAFE");
1521 * Dump details about a event.
1524 db_dump_intr_event(struct intr_event *ie, int handlers)
1526 struct intr_handler *ih;
1527 struct intr_thread *it;
1530 db_printf("%s ", ie->ie_fullname);
1533 db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1535 db_printf("(no thread)");
1536 if ((ie->ie_flags & (IE_SOFT | IE_ADDING_THREAD)) != 0 ||
1537 (it != NULL && it->it_need)) {
1540 if (ie->ie_flags & IE_SOFT) {
1544 if (ie->ie_flags & IE_ADDING_THREAD) {
1547 db_printf("ADDING_THREAD");
1550 if (it != NULL && it->it_need) {
1560 CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next)
1561 db_dump_intrhand(ih);
1565 * Dump data about interrupt handlers
1567 DB_SHOW_COMMAND(intr, db_show_intr)
1569 struct intr_event *ie;
1572 verbose = strchr(modif, 'v') != NULL;
1573 all = strchr(modif, 'a') != NULL;
1574 TAILQ_FOREACH(ie, &event_list, ie_list) {
1575 if (!all && CK_SLIST_EMPTY(&ie->ie_handlers))
1577 db_dump_intr_event(ie, verbose);
1585 * Start standard software interrupt threads
1588 start_softintr(void *dummy)
1591 if (swi_add(&clk_intr_event, "clk", NULL, NULL, SWI_CLOCK,
1593 panic("died while creating clk swi ithread");
1595 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1599 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1600 * The data for this machine dependent, and the declarations are in machine
1601 * dependent code. The layout of intrnames and intrcnt however is machine
1604 * We do not know the length of intrcnt and intrnames at compile time, so
1605 * calculate things at run time.
1608 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1610 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1613 SYSCTL_PROC(_hw, OID_AUTO, intrnames,
1614 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
1615 sysctl_intrnames, "",
1619 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1622 uint32_t *intrcnt32;
1626 if (req->flags & SCTL_MASK32) {
1628 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1629 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1630 if (intrcnt32 == NULL)
1632 for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1633 intrcnt32[i] = intrcnt[i];
1634 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1635 free(intrcnt32, M_TEMP);
1639 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1642 SYSCTL_PROC(_hw, OID_AUTO, intrcnt,
1643 CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
1645 "Interrupt Counts");
1649 * DDB command to dump the interrupt statistics.
1651 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
1659 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1664 db_printf("%s\t%lu\n", cp, *i);
1665 cp += strlen(cp) + 1;