xref: /freebsd/sys/kern/kern_intr.c (revision 780fb4a2fa9a9aee5ac48a60b790f567c0dc13e9)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_ddb.h"
33 #include "opt_kstack_usage_prof.h"
34 
35 #include <sys/param.h>
36 #include <sys/bus.h>
37 #include <sys/conf.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>
44 #include <sys/ktr.h>
45 #include <sys/limits.h>
46 #include <sys/lock.h>
47 #include <sys/malloc.h>
48 #include <sys/mutex.h>
49 #include <sys/priv.h>
50 #include <sys/proc.h>
51 #include <sys/random.h>
52 #include <sys/resourcevar.h>
53 #include <sys/sched.h>
54 #include <sys/smp.h>
55 #include <sys/sysctl.h>
56 #include <sys/syslog.h>
57 #include <sys/unistd.h>
58 #include <sys/vmmeter.h>
59 #include <machine/atomic.h>
60 #include <machine/cpu.h>
61 #include <machine/md_var.h>
62 #include <machine/stdarg.h>
63 #ifdef DDB
64 #include <ddb/ddb.h>
65 #include <ddb/db_sym.h>
66 #endif
67 
68 /*
69  * Describe an interrupt thread.  There is one of these per interrupt event.
70  */
71 struct intr_thread {
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. */
76 };
77 
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. */
81 
82 struct	intr_entropy {
83 	struct	thread *td;
84 	uintptr_t event;
85 };
86 
87 struct	intr_event *clk_intr_event;
88 struct	intr_event *tty_intr_event;
89 void	*vm_ih;
90 struct proc *intrproc;
91 
92 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
93 
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);
102 
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 *);
112 
113 /* Map an interrupt type to an ithread priority. */
114 u_char
115 intr_priority(enum intr_type flags)
116 {
117 	u_char pri;
118 
119 	flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET |
120 	    INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV);
121 	switch (flags) {
122 	case INTR_TYPE_TTY:
123 		pri = PI_TTY;
124 		break;
125 	case INTR_TYPE_BIO:
126 		pri = PI_DISK;
127 		break;
128 	case INTR_TYPE_NET:
129 		pri = PI_NET;
130 		break;
131 	case INTR_TYPE_CAM:
132 		pri = PI_DISK;
133 		break;
134 	case INTR_TYPE_AV:
135 		pri = PI_AV;
136 		break;
137 	case INTR_TYPE_CLK:
138 		pri = PI_REALTIME;
139 		break;
140 	case INTR_TYPE_MISC:
141 		pri = PI_DULL;          /* don't care */
142 		break;
143 	default:
144 		/* We didn't specify an interrupt level. */
145 		panic("intr_priority: no interrupt type in flags");
146 	}
147 
148 	return pri;
149 }
150 
151 /*
152  * Update an ithread based on the associated intr_event.
153  */
154 static void
155 ithread_update(struct intr_thread *ithd)
156 {
157 	struct intr_event *ie;
158 	struct thread *td;
159 	u_char pri;
160 
161 	ie = ithd->it_event;
162 	td = ithd->it_thread;
163 
164 	/* Determine the overall priority of this event. */
165 	if (TAILQ_EMPTY(&ie->ie_handlers))
166 		pri = PRI_MAX_ITHD;
167 	else
168 		pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri;
169 
170 	/* Update name and priority. */
171 	strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
172 #ifdef KTR
173 	sched_clear_tdname(td);
174 #endif
175 	thread_lock(td);
176 	sched_prio(td, pri);
177 	thread_unlock(td);
178 }
179 
180 /*
181  * Regenerate the full name of an interrupt event and update its priority.
182  */
183 static void
184 intr_event_update(struct intr_event *ie)
185 {
186 	struct intr_handler *ih;
187 	char *last;
188 	int missed, space;
189 
190 	/* Start off with no entropy and just the name of the event. */
191 	mtx_assert(&ie->ie_lock, MA_OWNED);
192 	strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
193 	ie->ie_flags &= ~IE_ENTROPY;
194 	missed = 0;
195 	space = 1;
196 
197 	/* Run through all the handlers updating values. */
198 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
199 		if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
200 		    sizeof(ie->ie_fullname)) {
201 			strcat(ie->ie_fullname, " ");
202 			strcat(ie->ie_fullname, ih->ih_name);
203 			space = 0;
204 		} else
205 			missed++;
206 		if (ih->ih_flags & IH_ENTROPY)
207 			ie->ie_flags |= IE_ENTROPY;
208 	}
209 
210 	/*
211 	 * If the handler names were too long, add +'s to indicate missing
212 	 * names. If we run out of room and still have +'s to add, change
213 	 * the last character from a + to a *.
214 	 */
215 	last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
216 	while (missed-- > 0) {
217 		if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {
218 			if (*last == '+') {
219 				*last = '*';
220 				break;
221 			} else
222 				*last = '+';
223 		} else if (space) {
224 			strcat(ie->ie_fullname, " +");
225 			space = 0;
226 		} else
227 			strcat(ie->ie_fullname, "+");
228 	}
229 
230 	/*
231 	 * If this event has an ithread, update it's priority and
232 	 * name.
233 	 */
234 	if (ie->ie_thread != NULL)
235 		ithread_update(ie->ie_thread);
236 	CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname);
237 }
238 
239 int
240 intr_event_create(struct intr_event **event, void *source, int flags, int irq,
241     void (*pre_ithread)(void *), void (*post_ithread)(void *),
242     void (*post_filter)(void *), int (*assign_cpu)(void *, int),
243     const char *fmt, ...)
244 {
245 	struct intr_event *ie;
246 	va_list ap;
247 
248 	/* The only valid flag during creation is IE_SOFT. */
249 	if ((flags & ~IE_SOFT) != 0)
250 		return (EINVAL);
251 	ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
252 	ie->ie_source = source;
253 	ie->ie_pre_ithread = pre_ithread;
254 	ie->ie_post_ithread = post_ithread;
255 	ie->ie_post_filter = post_filter;
256 	ie->ie_assign_cpu = assign_cpu;
257 	ie->ie_flags = flags;
258 	ie->ie_irq = irq;
259 	ie->ie_cpu = NOCPU;
260 	TAILQ_INIT(&ie->ie_handlers);
261 	mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
262 
263 	va_start(ap, fmt);
264 	vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap);
265 	va_end(ap);
266 	strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname));
267 	mtx_lock(&event_lock);
268 	TAILQ_INSERT_TAIL(&event_list, ie, ie_list);
269 	mtx_unlock(&event_lock);
270 	if (event != NULL)
271 		*event = ie;
272 	CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name);
273 	return (0);
274 }
275 
276 /*
277  * Bind an interrupt event to the specified CPU.  Note that not all
278  * platforms support binding an interrupt to a CPU.  For those
279  * platforms this request will fail.  Using a cpu id of NOCPU unbinds
280  * the interrupt event.
281  */
282 static int
283 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread)
284 {
285 	lwpid_t id;
286 	int error;
287 
288 	/* Need a CPU to bind to. */
289 	if (cpu != NOCPU && CPU_ABSENT(cpu))
290 		return (EINVAL);
291 
292 	if (ie->ie_assign_cpu == NULL)
293 		return (EOPNOTSUPP);
294 
295 	error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR);
296 	if (error)
297 		return (error);
298 
299 	/*
300 	 * If we have any ithreads try to set their mask first to verify
301 	 * permissions, etc.
302 	 */
303 	if (bindithread) {
304 		mtx_lock(&ie->ie_lock);
305 		if (ie->ie_thread != NULL) {
306 			id = ie->ie_thread->it_thread->td_tid;
307 			mtx_unlock(&ie->ie_lock);
308 			error = cpuset_setithread(id, cpu);
309 			if (error)
310 				return (error);
311 		} else
312 			mtx_unlock(&ie->ie_lock);
313 	}
314 	if (bindirq)
315 		error = ie->ie_assign_cpu(ie->ie_source, cpu);
316 	if (error) {
317 		if (bindithread) {
318 			mtx_lock(&ie->ie_lock);
319 			if (ie->ie_thread != NULL) {
320 				cpu = ie->ie_cpu;
321 				id = ie->ie_thread->it_thread->td_tid;
322 				mtx_unlock(&ie->ie_lock);
323 				(void)cpuset_setithread(id, cpu);
324 			} else
325 				mtx_unlock(&ie->ie_lock);
326 		}
327 		return (error);
328 	}
329 
330 	if (bindirq) {
331 		mtx_lock(&ie->ie_lock);
332 		ie->ie_cpu = cpu;
333 		mtx_unlock(&ie->ie_lock);
334 	}
335 
336 	return (error);
337 }
338 
339 /*
340  * Bind an interrupt event to the specified CPU.  For supported platforms, any
341  * associated ithreads as well as the primary interrupt context will be bound
342  * to the specificed CPU.
343  */
344 int
345 intr_event_bind(struct intr_event *ie, int cpu)
346 {
347 
348 	return (_intr_event_bind(ie, cpu, true, true));
349 }
350 
351 /*
352  * Bind an interrupt event to the specified CPU, but do not bind associated
353  * ithreads.
354  */
355 int
356 intr_event_bind_irqonly(struct intr_event *ie, int cpu)
357 {
358 
359 	return (_intr_event_bind(ie, cpu, true, false));
360 }
361 
362 /*
363  * Bind an interrupt event's ithread to the specified CPU.
364  */
365 int
366 intr_event_bind_ithread(struct intr_event *ie, int cpu)
367 {
368 
369 	return (_intr_event_bind(ie, cpu, false, true));
370 }
371 
372 static struct intr_event *
373 intr_lookup(int irq)
374 {
375 	struct intr_event *ie;
376 
377 	mtx_lock(&event_lock);
378 	TAILQ_FOREACH(ie, &event_list, ie_list)
379 		if (ie->ie_irq == irq &&
380 		    (ie->ie_flags & IE_SOFT) == 0 &&
381 		    TAILQ_FIRST(&ie->ie_handlers) != NULL)
382 			break;
383 	mtx_unlock(&event_lock);
384 	return (ie);
385 }
386 
387 int
388 intr_setaffinity(int irq, int mode, void *m)
389 {
390 	struct intr_event *ie;
391 	cpuset_t *mask;
392 	int cpu, n;
393 
394 	mask = m;
395 	cpu = NOCPU;
396 	/*
397 	 * If we're setting all cpus we can unbind.  Otherwise make sure
398 	 * only one cpu is in the set.
399 	 */
400 	if (CPU_CMP(cpuset_root, mask)) {
401 		for (n = 0; n < CPU_SETSIZE; n++) {
402 			if (!CPU_ISSET(n, mask))
403 				continue;
404 			if (cpu != NOCPU)
405 				return (EINVAL);
406 			cpu = n;
407 		}
408 	}
409 	ie = intr_lookup(irq);
410 	if (ie == NULL)
411 		return (ESRCH);
412 	switch (mode) {
413 	case CPU_WHICH_IRQ:
414 		return (intr_event_bind(ie, cpu));
415 	case CPU_WHICH_INTRHANDLER:
416 		return (intr_event_bind_irqonly(ie, cpu));
417 	case CPU_WHICH_ITHREAD:
418 		return (intr_event_bind_ithread(ie, cpu));
419 	default:
420 		return (EINVAL);
421 	}
422 }
423 
424 int
425 intr_getaffinity(int irq, int mode, void *m)
426 {
427 	struct intr_event *ie;
428 	struct thread *td;
429 	struct proc *p;
430 	cpuset_t *mask;
431 	lwpid_t id;
432 	int error;
433 
434 	mask = m;
435 	ie = intr_lookup(irq);
436 	if (ie == NULL)
437 		return (ESRCH);
438 
439 	error = 0;
440 	CPU_ZERO(mask);
441 	switch (mode) {
442 	case CPU_WHICH_IRQ:
443 	case CPU_WHICH_INTRHANDLER:
444 		mtx_lock(&ie->ie_lock);
445 		if (ie->ie_cpu == NOCPU)
446 			CPU_COPY(cpuset_root, mask);
447 		else
448 			CPU_SET(ie->ie_cpu, mask);
449 		mtx_unlock(&ie->ie_lock);
450 		break;
451 	case CPU_WHICH_ITHREAD:
452 		mtx_lock(&ie->ie_lock);
453 		if (ie->ie_thread == NULL) {
454 			mtx_unlock(&ie->ie_lock);
455 			CPU_COPY(cpuset_root, mask);
456 		} else {
457 			id = ie->ie_thread->it_thread->td_tid;
458 			mtx_unlock(&ie->ie_lock);
459 			error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL);
460 			if (error != 0)
461 				return (error);
462 			CPU_COPY(&td->td_cpuset->cs_mask, mask);
463 			PROC_UNLOCK(p);
464 		}
465 	default:
466 		return (EINVAL);
467 	}
468 	return (0);
469 }
470 
471 int
472 intr_event_destroy(struct intr_event *ie)
473 {
474 
475 	mtx_lock(&event_lock);
476 	mtx_lock(&ie->ie_lock);
477 	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
478 		mtx_unlock(&ie->ie_lock);
479 		mtx_unlock(&event_lock);
480 		return (EBUSY);
481 	}
482 	TAILQ_REMOVE(&event_list, ie, ie_list);
483 #ifndef notyet
484 	if (ie->ie_thread != NULL) {
485 		ithread_destroy(ie->ie_thread);
486 		ie->ie_thread = NULL;
487 	}
488 #endif
489 	mtx_unlock(&ie->ie_lock);
490 	mtx_unlock(&event_lock);
491 	mtx_destroy(&ie->ie_lock);
492 	free(ie, M_ITHREAD);
493 	return (0);
494 }
495 
496 static struct intr_thread *
497 ithread_create(const char *name)
498 {
499 	struct intr_thread *ithd;
500 	struct thread *td;
501 	int error;
502 
503 	ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
504 
505 	error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
506 		    &td, RFSTOPPED | RFHIGHPID,
507 	    	    0, "intr", "%s", name);
508 	if (error)
509 		panic("kproc_create() failed with %d", error);
510 	thread_lock(td);
511 	sched_class(td, PRI_ITHD);
512 	TD_SET_IWAIT(td);
513 	thread_unlock(td);
514 	td->td_pflags |= TDP_ITHREAD;
515 	ithd->it_thread = td;
516 	CTR2(KTR_INTR, "%s: created %s", __func__, name);
517 	return (ithd);
518 }
519 
520 static void
521 ithread_destroy(struct intr_thread *ithread)
522 {
523 	struct thread *td;
524 
525 	CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name);
526 	td = ithread->it_thread;
527 	thread_lock(td);
528 	ithread->it_flags |= IT_DEAD;
529 	if (TD_AWAITING_INTR(td)) {
530 		TD_CLR_IWAIT(td);
531 		sched_add(td, SRQ_INTR);
532 	}
533 	thread_unlock(td);
534 }
535 
536 int
537 intr_event_add_handler(struct intr_event *ie, const char *name,
538     driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri,
539     enum intr_type flags, void **cookiep)
540 {
541 	struct intr_handler *ih, *temp_ih;
542 	struct intr_thread *it;
543 
544 	if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
545 		return (EINVAL);
546 
547 	/* Allocate and populate an interrupt handler structure. */
548 	ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO);
549 	ih->ih_filter = filter;
550 	ih->ih_handler = handler;
551 	ih->ih_argument = arg;
552 	strlcpy(ih->ih_name, name, sizeof(ih->ih_name));
553 	ih->ih_event = ie;
554 	ih->ih_pri = pri;
555 	if (flags & INTR_EXCL)
556 		ih->ih_flags = IH_EXCLUSIVE;
557 	if (flags & INTR_MPSAFE)
558 		ih->ih_flags |= IH_MPSAFE;
559 	if (flags & INTR_ENTROPY)
560 		ih->ih_flags |= IH_ENTROPY;
561 
562 	/* We can only have one exclusive handler in a event. */
563 	mtx_lock(&ie->ie_lock);
564 	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
565 		if ((flags & INTR_EXCL) ||
566 		    (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
567 			mtx_unlock(&ie->ie_lock);
568 			free(ih, M_ITHREAD);
569 			return (EINVAL);
570 		}
571 	}
572 
573 	/* Create a thread if we need one. */
574 	while (ie->ie_thread == NULL && handler != NULL) {
575 		if (ie->ie_flags & IE_ADDING_THREAD)
576 			msleep(ie, &ie->ie_lock, 0, "ithread", 0);
577 		else {
578 			ie->ie_flags |= IE_ADDING_THREAD;
579 			mtx_unlock(&ie->ie_lock);
580 			it = ithread_create("intr: newborn");
581 			mtx_lock(&ie->ie_lock);
582 			ie->ie_flags &= ~IE_ADDING_THREAD;
583 			ie->ie_thread = it;
584 			it->it_event = ie;
585 			ithread_update(it);
586 			wakeup(ie);
587 		}
588 	}
589 
590 	/* Add the new handler to the event in priority order. */
591 	TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
592 		if (temp_ih->ih_pri > ih->ih_pri)
593 			break;
594 	}
595 	if (temp_ih == NULL)
596 		TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
597 	else
598 		TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
599 	intr_event_update(ie);
600 
601 	CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
602 	    ie->ie_name);
603 	mtx_unlock(&ie->ie_lock);
604 
605 	if (cookiep != NULL)
606 		*cookiep = ih;
607 	return (0);
608 }
609 
610 /*
611  * Append a description preceded by a ':' to the name of the specified
612  * interrupt handler.
613  */
614 int
615 intr_event_describe_handler(struct intr_event *ie, void *cookie,
616     const char *descr)
617 {
618 	struct intr_handler *ih;
619 	size_t space;
620 	char *start;
621 
622 	mtx_lock(&ie->ie_lock);
623 #ifdef INVARIANTS
624 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
625 		if (ih == cookie)
626 			break;
627 	}
628 	if (ih == NULL) {
629 		mtx_unlock(&ie->ie_lock);
630 		panic("handler %p not found in interrupt event %p", cookie, ie);
631 	}
632 #endif
633 	ih = cookie;
634 
635 	/*
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.
641 	 */
642 	start = strchr(ih->ih_name, ':');
643 	if (start == NULL)
644 		start = strchr(ih->ih_name, 0);
645 
646 	/*
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.
650 	 */
651 	space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
652 	if (strlen(descr) + 1 > space) {
653 		mtx_unlock(&ie->ie_lock);
654 		return (ENOSPC);
655 	}
656 
657 	/* Append a colon followed by the description. */
658 	*start = ':';
659 	strcpy(start + 1, descr);
660 	intr_event_update(ie);
661 	mtx_unlock(&ie->ie_lock);
662 	return (0);
663 }
664 
665 /*
666  * Return the ie_source field from the intr_event an intr_handler is
667  * associated with.
668  */
669 void *
670 intr_handler_source(void *cookie)
671 {
672 	struct intr_handler *ih;
673 	struct intr_event *ie;
674 
675 	ih = (struct intr_handler *)cookie;
676 	if (ih == NULL)
677 		return (NULL);
678 	ie = ih->ih_event;
679 	KASSERT(ie != NULL,
680 	    ("interrupt handler \"%s\" has a NULL interrupt event",
681 	    ih->ih_name));
682 	return (ie->ie_source);
683 }
684 
685 /*
686  * Sleep until an ithread finishes executing an interrupt handler.
687  *
688  * XXX Doesn't currently handle interrupt filters or fast interrupt
689  * handlers.  This is intended for compatibility with linux drivers
690  * only.  Do not use in BSD code.
691  */
692 void
693 _intr_drain(int irq)
694 {
695 	struct intr_event *ie;
696 	struct intr_thread *ithd;
697 	struct thread *td;
698 
699 	ie = intr_lookup(irq);
700 	if (ie == NULL)
701 		return;
702 	if (ie->ie_thread == NULL)
703 		return;
704 	ithd = ie->ie_thread;
705 	td = ithd->it_thread;
706 	/*
707 	 * We set the flag and wait for it to be cleared to avoid
708 	 * long delays with potentially busy interrupt handlers
709 	 * were we to only sample TD_AWAITING_INTR() every tick.
710 	 */
711 	thread_lock(td);
712 	if (!TD_AWAITING_INTR(td)) {
713 		ithd->it_flags |= IT_WAIT;
714 		while (ithd->it_flags & IT_WAIT) {
715 			thread_unlock(td);
716 			pause("idrain", 1);
717 			thread_lock(td);
718 		}
719 	}
720 	thread_unlock(td);
721 	return;
722 }
723 
724 
725 int
726 intr_event_remove_handler(void *cookie)
727 {
728 	struct intr_handler *handler = (struct intr_handler *)cookie;
729 	struct intr_event *ie;
730 #ifdef INVARIANTS
731 	struct intr_handler *ih;
732 #endif
733 #ifdef notyet
734 	int dead;
735 #endif
736 
737 	if (handler == NULL)
738 		return (EINVAL);
739 	ie = handler->ih_event;
740 	KASSERT(ie != NULL,
741 	    ("interrupt handler \"%s\" has a NULL interrupt event",
742 	    handler->ih_name));
743 	mtx_lock(&ie->ie_lock);
744 	CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
745 	    ie->ie_name);
746 #ifdef INVARIANTS
747 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
748 		if (ih == handler)
749 			goto ok;
750 	mtx_unlock(&ie->ie_lock);
751 	panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
752 	    ih->ih_name, ie->ie_name);
753 ok:
754 #endif
755 	/*
756 	 * If there is no ithread, then just remove the handler and return.
757 	 * XXX: Note that an INTR_FAST handler might be running on another
758 	 * CPU!
759 	 */
760 	if (ie->ie_thread == NULL) {
761 		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
762 		mtx_unlock(&ie->ie_lock);
763 		free(handler, M_ITHREAD);
764 		return (0);
765 	}
766 
767 	/*
768 	 * If the interrupt thread is already running, then just mark this
769 	 * handler as being dead and let the ithread do the actual removal.
770 	 *
771 	 * During a cold boot while cold is set, msleep() does not sleep,
772 	 * so we have to remove the handler here rather than letting the
773 	 * thread do it.
774 	 */
775 	thread_lock(ie->ie_thread->it_thread);
776 	if (!TD_AWAITING_INTR(ie->ie_thread->it_thread) && !cold) {
777 		handler->ih_flags |= IH_DEAD;
778 
779 		/*
780 		 * Ensure that the thread will process the handler list
781 		 * again and remove this handler if it has already passed
782 		 * it on the list.
783 		 *
784 		 * The release part of the following store ensures
785 		 * that the update of ih_flags is ordered before the
786 		 * it_need setting.  See the comment before
787 		 * atomic_cmpset_acq(&ithd->it_need, ...) operation in
788 		 * the ithread_execute_handlers().
789 		 */
790 		atomic_store_rel_int(&ie->ie_thread->it_need, 1);
791 	} else
792 		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
793 	thread_unlock(ie->ie_thread->it_thread);
794 	while (handler->ih_flags & IH_DEAD)
795 		msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
796 	intr_event_update(ie);
797 #ifdef notyet
798 	/*
799 	 * XXX: This could be bad in the case of ppbus(8).  Also, I think
800 	 * this could lead to races of stale data when servicing an
801 	 * interrupt.
802 	 */
803 	dead = 1;
804 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
805 		if (!(ih->ih_flags & IH_FAST)) {
806 			dead = 0;
807 			break;
808 		}
809 	}
810 	if (dead) {
811 		ithread_destroy(ie->ie_thread);
812 		ie->ie_thread = NULL;
813 	}
814 #endif
815 	mtx_unlock(&ie->ie_lock);
816 	free(handler, M_ITHREAD);
817 	return (0);
818 }
819 
820 static int
821 intr_event_schedule_thread(struct intr_event *ie)
822 {
823 	struct intr_entropy entropy;
824 	struct intr_thread *it;
825 	struct thread *td;
826 	struct thread *ctd;
827 
828 	/*
829 	 * If no ithread or no handlers, then we have a stray interrupt.
830 	 */
831 	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) ||
832 	    ie->ie_thread == NULL)
833 		return (EINVAL);
834 
835 	ctd = curthread;
836 	it = ie->ie_thread;
837 	td = it->it_thread;
838 
839 	/*
840 	 * If any of the handlers for this ithread claim to be good
841 	 * sources of entropy, then gather some.
842 	 */
843 	if (ie->ie_flags & IE_ENTROPY) {
844 		entropy.event = (uintptr_t)ie;
845 		entropy.td = ctd;
846 		random_harvest_queue(&entropy, sizeof(entropy), 2, RANDOM_INTERRUPT);
847 	}
848 
849 	KASSERT(td->td_proc != NULL, ("ithread %s has no process", ie->ie_name));
850 
851 	/*
852 	 * Set it_need to tell the thread to keep running if it is already
853 	 * running.  Then, lock the thread and see if we actually need to
854 	 * put it on the runqueue.
855 	 *
856 	 * Use store_rel to arrange that the store to ih_need in
857 	 * swi_sched() is before the store to it_need and prepare for
858 	 * transfer of this order to loads in the ithread.
859 	 */
860 	atomic_store_rel_int(&it->it_need, 1);
861 	thread_lock(td);
862 	if (TD_AWAITING_INTR(td)) {
863 		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, td->td_proc->p_pid,
864 		    td->td_name);
865 		TD_CLR_IWAIT(td);
866 		sched_add(td, SRQ_INTR);
867 	} else {
868 		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
869 		    __func__, td->td_proc->p_pid, td->td_name, it->it_need, td->td_state);
870 	}
871 	thread_unlock(td);
872 
873 	return (0);
874 }
875 
876 /*
877  * Allow interrupt event binding for software interrupt handlers -- a no-op,
878  * since interrupts are generated in software rather than being directed by
879  * a PIC.
880  */
881 static int
882 swi_assign_cpu(void *arg, int cpu)
883 {
884 
885 	return (0);
886 }
887 
888 /*
889  * Add a software interrupt handler to a specified event.  If a given event
890  * is not specified, then a new event is created.
891  */
892 int
893 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler,
894 	    void *arg, int pri, enum intr_type flags, void **cookiep)
895 {
896 	struct intr_event *ie;
897 	int error;
898 
899 	if (flags & INTR_ENTROPY)
900 		return (EINVAL);
901 
902 	ie = (eventp != NULL) ? *eventp : NULL;
903 
904 	if (ie != NULL) {
905 		if (!(ie->ie_flags & IE_SOFT))
906 			return (EINVAL);
907 	} else {
908 		error = intr_event_create(&ie, NULL, IE_SOFT, 0,
909 		    NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri);
910 		if (error)
911 			return (error);
912 		if (eventp != NULL)
913 			*eventp = ie;
914 	}
915 	error = intr_event_add_handler(ie, name, NULL, handler, arg,
916 	    PI_SWI(pri), flags, cookiep);
917 	return (error);
918 }
919 
920 /*
921  * Schedule a software interrupt thread.
922  */
923 void
924 swi_sched(void *cookie, int flags)
925 {
926 	struct intr_handler *ih = (struct intr_handler *)cookie;
927 	struct intr_event *ie = ih->ih_event;
928 	struct intr_entropy entropy;
929 	int error __unused;
930 
931 	CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name,
932 	    ih->ih_need);
933 
934 	entropy.event = (uintptr_t)ih;
935 	entropy.td = curthread;
936 	random_harvest_queue(&entropy, sizeof(entropy), 1, RANDOM_SWI);
937 
938 	/*
939 	 * Set ih_need for this handler so that if the ithread is already
940 	 * running it will execute this handler on the next pass.  Otherwise,
941 	 * it will execute it the next time it runs.
942 	 */
943 	ih->ih_need = 1;
944 
945 	if (!(flags & SWI_DELAY)) {
946 		VM_CNT_INC(v_soft);
947 		error = intr_event_schedule_thread(ie);
948 		KASSERT(error == 0, ("stray software interrupt"));
949 	}
950 }
951 
952 /*
953  * Remove a software interrupt handler.  Currently this code does not
954  * remove the associated interrupt event if it becomes empty.  Calling code
955  * may do so manually via intr_event_destroy(), but that's not really
956  * an optimal interface.
957  */
958 int
959 swi_remove(void *cookie)
960 {
961 
962 	return (intr_event_remove_handler(cookie));
963 }
964 
965 
966 /*
967  * This is a public function for use by drivers that mux interrupt
968  * handlers for child devices from their interrupt handler.
969  */
970 void
971 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
972 {
973 	struct intr_handler *ih, *ihn;
974 
975 	TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
976 		/*
977 		 * If this handler is marked for death, remove it from
978 		 * the list of handlers and wake up the sleeper.
979 		 */
980 		if (ih->ih_flags & IH_DEAD) {
981 			mtx_lock(&ie->ie_lock);
982 			TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
983 			ih->ih_flags &= ~IH_DEAD;
984 			wakeup(ih);
985 			mtx_unlock(&ie->ie_lock);
986 			continue;
987 		}
988 
989 		/* Skip filter only handlers */
990 		if (ih->ih_handler == NULL)
991 			continue;
992 
993 		/*
994 		 * For software interrupt threads, we only execute
995 		 * handlers that have their need flag set.  Hardware
996 		 * interrupt threads always invoke all of their handlers.
997 		 *
998 		 * ih_need can only be 0 or 1.  Failed cmpset below
999 		 * means that there is no request to execute handlers,
1000 		 * so a retry of the cmpset is not needed.
1001 		 */
1002 		if ((ie->ie_flags & IE_SOFT) != 0 &&
1003 		    atomic_cmpset_int(&ih->ih_need, 1, 0) == 0)
1004 			continue;
1005 
1006 		/* Execute this handler. */
1007 		CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x",
1008 		    __func__, p->p_pid, (void *)ih->ih_handler,
1009 		    ih->ih_argument, ih->ih_name, ih->ih_flags);
1010 
1011 		if (!(ih->ih_flags & IH_MPSAFE))
1012 			mtx_lock(&Giant);
1013 		ih->ih_handler(ih->ih_argument);
1014 		if (!(ih->ih_flags & IH_MPSAFE))
1015 			mtx_unlock(&Giant);
1016 	}
1017 }
1018 
1019 static void
1020 ithread_execute_handlers(struct proc *p, struct intr_event *ie)
1021 {
1022 
1023 	/* Interrupt handlers should not sleep. */
1024 	if (!(ie->ie_flags & IE_SOFT))
1025 		THREAD_NO_SLEEPING();
1026 	intr_event_execute_handlers(p, ie);
1027 	if (!(ie->ie_flags & IE_SOFT))
1028 		THREAD_SLEEPING_OK();
1029 
1030 	/*
1031 	 * Interrupt storm handling:
1032 	 *
1033 	 * If this interrupt source is currently storming, then throttle
1034 	 * it to only fire the handler once  per clock tick.
1035 	 *
1036 	 * If this interrupt source is not currently storming, but the
1037 	 * number of back to back interrupts exceeds the storm threshold,
1038 	 * then enter storming mode.
1039 	 */
1040 	if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold &&
1041 	    !(ie->ie_flags & IE_SOFT)) {
1042 		/* Report the message only once every second. */
1043 		if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) {
1044 			printf(
1045 	"interrupt storm detected on \"%s\"; throttling interrupt source\n",
1046 			    ie->ie_name);
1047 		}
1048 		pause("istorm", 1);
1049 	} else
1050 		ie->ie_count++;
1051 
1052 	/*
1053 	 * Now that all the handlers have had a chance to run, reenable
1054 	 * the interrupt source.
1055 	 */
1056 	if (ie->ie_post_ithread != NULL)
1057 		ie->ie_post_ithread(ie->ie_source);
1058 }
1059 
1060 /*
1061  * This is the main code for interrupt threads.
1062  */
1063 static void
1064 ithread_loop(void *arg)
1065 {
1066 	struct intr_thread *ithd;
1067 	struct intr_event *ie;
1068 	struct thread *td;
1069 	struct proc *p;
1070 	int wake;
1071 
1072 	td = curthread;
1073 	p = td->td_proc;
1074 	ithd = (struct intr_thread *)arg;
1075 	KASSERT(ithd->it_thread == td,
1076 	    ("%s: ithread and proc linkage out of sync", __func__));
1077 	ie = ithd->it_event;
1078 	ie->ie_count = 0;
1079 	wake = 0;
1080 
1081 	/*
1082 	 * As long as we have interrupts outstanding, go through the
1083 	 * list of handlers, giving each one a go at it.
1084 	 */
1085 	for (;;) {
1086 		/*
1087 		 * If we are an orphaned thread, then just die.
1088 		 */
1089 		if (ithd->it_flags & IT_DEAD) {
1090 			CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
1091 			    p->p_pid, td->td_name);
1092 			free(ithd, M_ITHREAD);
1093 			kthread_exit();
1094 		}
1095 
1096 		/*
1097 		 * Service interrupts.  If another interrupt arrives while
1098 		 * we are running, it will set it_need to note that we
1099 		 * should make another pass.
1100 		 *
1101 		 * The load_acq part of the following cmpset ensures
1102 		 * that the load of ih_need in ithread_execute_handlers()
1103 		 * is ordered after the load of it_need here.
1104 		 */
1105 		while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0)
1106 			ithread_execute_handlers(p, ie);
1107 		WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread");
1108 		mtx_assert(&Giant, MA_NOTOWNED);
1109 
1110 		/*
1111 		 * Processed all our interrupts.  Now get the sched
1112 		 * lock.  This may take a while and it_need may get
1113 		 * set again, so we have to check it again.
1114 		 */
1115 		thread_lock(td);
1116 		if (atomic_load_acq_int(&ithd->it_need) == 0 &&
1117 		    (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) {
1118 			TD_SET_IWAIT(td);
1119 			ie->ie_count = 0;
1120 			mi_switch(SW_VOL | SWT_IWAIT, NULL);
1121 		}
1122 		if (ithd->it_flags & IT_WAIT) {
1123 			wake = 1;
1124 			ithd->it_flags &= ~IT_WAIT;
1125 		}
1126 		thread_unlock(td);
1127 		if (wake) {
1128 			wakeup(ithd);
1129 			wake = 0;
1130 		}
1131 	}
1132 }
1133 
1134 /*
1135  * Main interrupt handling body.
1136  *
1137  * Input:
1138  * o ie:                        the event connected to this interrupt.
1139  * o frame:                     some archs (i.e. i386) pass a frame to some.
1140  *                              handlers as their main argument.
1141  * Return value:
1142  * o 0:                         everything ok.
1143  * o EINVAL:                    stray interrupt.
1144  */
1145 int
1146 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
1147 {
1148 	struct intr_handler *ih;
1149 	struct trapframe *oldframe;
1150 	struct thread *td;
1151 	int ret, thread;
1152 
1153 	td = curthread;
1154 
1155 #ifdef KSTACK_USAGE_PROF
1156 	intr_prof_stack_use(td, frame);
1157 #endif
1158 
1159 	/* An interrupt with no event or handlers is a stray interrupt. */
1160 	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
1161 		return (EINVAL);
1162 
1163 	/*
1164 	 * Execute fast interrupt handlers directly.
1165 	 * To support clock handlers, if a handler registers
1166 	 * with a NULL argument, then we pass it a pointer to
1167 	 * a trapframe as its argument.
1168 	 */
1169 	td->td_intr_nesting_level++;
1170 	thread = 0;
1171 	ret = 0;
1172 	critical_enter();
1173 	oldframe = td->td_intr_frame;
1174 	td->td_intr_frame = frame;
1175 	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
1176 		if (ih->ih_filter == NULL) {
1177 			thread = 1;
1178 			continue;
1179 		}
1180 		CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__,
1181 		    ih->ih_filter, ih->ih_argument == NULL ? frame :
1182 		    ih->ih_argument, ih->ih_name);
1183 		if (ih->ih_argument == NULL)
1184 			ret = ih->ih_filter(frame);
1185 		else
1186 			ret = ih->ih_filter(ih->ih_argument);
1187 		KASSERT(ret == FILTER_STRAY ||
1188 		    ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 &&
1189 		    (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0),
1190 		    ("%s: incorrect return value %#x from %s", __func__, ret,
1191 		    ih->ih_name));
1192 
1193 		/*
1194 		 * Wrapper handler special handling:
1195 		 *
1196 		 * in some particular cases (like pccard and pccbb),
1197 		 * the _real_ device handler is wrapped in a couple of
1198 		 * functions - a filter wrapper and an ithread wrapper.
1199 		 * In this case (and just in this case), the filter wrapper
1200 		 * could ask the system to schedule the ithread and mask
1201 		 * the interrupt source if the wrapped handler is composed
1202 		 * of just an ithread handler.
1203 		 *
1204 		 * TODO: write a generic wrapper to avoid people rolling
1205 		 * their own
1206 		 */
1207 		if (!thread) {
1208 			if (ret == FILTER_SCHEDULE_THREAD)
1209 				thread = 1;
1210 		}
1211 	}
1212 	td->td_intr_frame = oldframe;
1213 
1214 	if (thread) {
1215 		if (ie->ie_pre_ithread != NULL)
1216 			ie->ie_pre_ithread(ie->ie_source);
1217 	} else {
1218 		if (ie->ie_post_filter != NULL)
1219 			ie->ie_post_filter(ie->ie_source);
1220 	}
1221 
1222 	/* Schedule the ithread if needed. */
1223 	if (thread) {
1224 		int error __unused;
1225 
1226 		error =  intr_event_schedule_thread(ie);
1227 		KASSERT(error == 0, ("bad stray interrupt"));
1228 	}
1229 	critical_exit();
1230 	td->td_intr_nesting_level--;
1231 	return (0);
1232 }
1233 
1234 #ifdef DDB
1235 /*
1236  * Dump details about an interrupt handler
1237  */
1238 static void
1239 db_dump_intrhand(struct intr_handler *ih)
1240 {
1241 	int comma;
1242 
1243 	db_printf("\t%-10s ", ih->ih_name);
1244 	switch (ih->ih_pri) {
1245 	case PI_REALTIME:
1246 		db_printf("CLK ");
1247 		break;
1248 	case PI_AV:
1249 		db_printf("AV  ");
1250 		break;
1251 	case PI_TTY:
1252 		db_printf("TTY ");
1253 		break;
1254 	case PI_NET:
1255 		db_printf("NET ");
1256 		break;
1257 	case PI_DISK:
1258 		db_printf("DISK");
1259 		break;
1260 	case PI_DULL:
1261 		db_printf("DULL");
1262 		break;
1263 	default:
1264 		if (ih->ih_pri >= PI_SOFT)
1265 			db_printf("SWI ");
1266 		else
1267 			db_printf("%4u", ih->ih_pri);
1268 		break;
1269 	}
1270 	db_printf(" ");
1271 	if (ih->ih_filter != NULL) {
1272 		db_printf("[F]");
1273 		db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC);
1274 	}
1275 	if (ih->ih_handler != NULL) {
1276 		if (ih->ih_filter != NULL)
1277 			db_printf(",");
1278 		db_printf("[H]");
1279 		db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC);
1280 	}
1281 	db_printf("(%p)", ih->ih_argument);
1282 	if (ih->ih_need ||
1283 	    (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD |
1284 	    IH_MPSAFE)) != 0) {
1285 		db_printf(" {");
1286 		comma = 0;
1287 		if (ih->ih_flags & IH_EXCLUSIVE) {
1288 			if (comma)
1289 				db_printf(", ");
1290 			db_printf("EXCL");
1291 			comma = 1;
1292 		}
1293 		if (ih->ih_flags & IH_ENTROPY) {
1294 			if (comma)
1295 				db_printf(", ");
1296 			db_printf("ENTROPY");
1297 			comma = 1;
1298 		}
1299 		if (ih->ih_flags & IH_DEAD) {
1300 			if (comma)
1301 				db_printf(", ");
1302 			db_printf("DEAD");
1303 			comma = 1;
1304 		}
1305 		if (ih->ih_flags & IH_MPSAFE) {
1306 			if (comma)
1307 				db_printf(", ");
1308 			db_printf("MPSAFE");
1309 			comma = 1;
1310 		}
1311 		if (ih->ih_need) {
1312 			if (comma)
1313 				db_printf(", ");
1314 			db_printf("NEED");
1315 		}
1316 		db_printf("}");
1317 	}
1318 	db_printf("\n");
1319 }
1320 
1321 /*
1322  * Dump details about a event.
1323  */
1324 void
1325 db_dump_intr_event(struct intr_event *ie, int handlers)
1326 {
1327 	struct intr_handler *ih;
1328 	struct intr_thread *it;
1329 	int comma;
1330 
1331 	db_printf("%s ", ie->ie_fullname);
1332 	it = ie->ie_thread;
1333 	if (it != NULL)
1334 		db_printf("(pid %d)", it->it_thread->td_proc->p_pid);
1335 	else
1336 		db_printf("(no thread)");
1337 	if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 ||
1338 	    (it != NULL && it->it_need)) {
1339 		db_printf(" {");
1340 		comma = 0;
1341 		if (ie->ie_flags & IE_SOFT) {
1342 			db_printf("SOFT");
1343 			comma = 1;
1344 		}
1345 		if (ie->ie_flags & IE_ENTROPY) {
1346 			if (comma)
1347 				db_printf(", ");
1348 			db_printf("ENTROPY");
1349 			comma = 1;
1350 		}
1351 		if (ie->ie_flags & IE_ADDING_THREAD) {
1352 			if (comma)
1353 				db_printf(", ");
1354 			db_printf("ADDING_THREAD");
1355 			comma = 1;
1356 		}
1357 		if (it != NULL && it->it_need) {
1358 			if (comma)
1359 				db_printf(", ");
1360 			db_printf("NEED");
1361 		}
1362 		db_printf("}");
1363 	}
1364 	db_printf("\n");
1365 
1366 	if (handlers)
1367 		TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
1368 		    db_dump_intrhand(ih);
1369 }
1370 
1371 /*
1372  * Dump data about interrupt handlers
1373  */
1374 DB_SHOW_COMMAND(intr, db_show_intr)
1375 {
1376 	struct intr_event *ie;
1377 	int all, verbose;
1378 
1379 	verbose = strchr(modif, 'v') != NULL;
1380 	all = strchr(modif, 'a') != NULL;
1381 	TAILQ_FOREACH(ie, &event_list, ie_list) {
1382 		if (!all && TAILQ_EMPTY(&ie->ie_handlers))
1383 			continue;
1384 		db_dump_intr_event(ie, verbose);
1385 		if (db_pager_quit)
1386 			break;
1387 	}
1388 }
1389 #endif /* DDB */
1390 
1391 /*
1392  * Start standard software interrupt threads
1393  */
1394 static void
1395 start_softintr(void *dummy)
1396 {
1397 
1398 	if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih))
1399 		panic("died while creating vm swi ithread");
1400 }
1401 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
1402     NULL);
1403 
1404 /*
1405  * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1406  * The data for this machine dependent, and the declarations are in machine
1407  * dependent code.  The layout of intrnames and intrcnt however is machine
1408  * independent.
1409  *
1410  * We do not know the length of intrcnt and intrnames at compile time, so
1411  * calculate things at run time.
1412  */
1413 static int
1414 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1415 {
1416 	return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req));
1417 }
1418 
1419 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1420     NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1421 
1422 static int
1423 sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
1424 {
1425 #ifdef SCTL_MASK32
1426 	uint32_t *intrcnt32;
1427 	unsigned i;
1428 	int error;
1429 
1430 	if (req->flags & SCTL_MASK32) {
1431 		if (!req->oldptr)
1432 			return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req));
1433 		intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT);
1434 		if (intrcnt32 == NULL)
1435 			return (ENOMEM);
1436 		for (i = 0; i < sintrcnt / sizeof (u_long); i++)
1437 			intrcnt32[i] = intrcnt[i];
1438 		error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req);
1439 		free(intrcnt32, M_TEMP);
1440 		return (error);
1441 	}
1442 #endif
1443 	return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req));
1444 }
1445 
1446 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1447     NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");
1448 
1449 #ifdef DDB
1450 /*
1451  * DDB command to dump the interrupt statistics.
1452  */
1453 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt)
1454 {
1455 	u_long *i;
1456 	char *cp;
1457 	u_int j;
1458 
1459 	cp = intrnames;
1460 	j = 0;
1461 	for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit;
1462 	    i++, j++) {
1463 		if (*cp == '\0')
1464 			break;
1465 		if (*i != 0)
1466 			db_printf("%s\t%lu\n", cp, *i);
1467 		cp += strlen(cp) + 1;
1468 	}
1469 }
1470 #endif
1471