xref: /dragonfly/sys/kern/kern_intr.c (revision 63823918)
1 /*
2  * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
3  * Copyright (c) 1997, Stefan Esser <se@freebsd.org> All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $FreeBSD: src/sys/kern/kern_intr.c,v 1.24.2.1 2001/10/14 20:05:50 luigi Exp $
27  *
28  */
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
33 #include <sys/kernel.h>
34 #include <sys/sysctl.h>
35 #include <sys/thread.h>
36 #include <sys/proc.h>
37 #include <sys/random.h>
38 #include <sys/serialize.h>
39 #include <sys/interrupt.h>
40 #include <sys/bus.h>
41 #include <sys/machintr.h>
42 
43 #include <machine/frame.h>
44 
45 #include <sys/thread2.h>
46 #include <sys/mplock2.h>
47 
48 struct intr_info;
49 
50 typedef struct intrec {
51     struct intrec *next;
52     struct intr_info *info;
53     inthand2_t	*handler;
54     void	*argument;
55     char	*name;
56     int		intr;
57     int		intr_flags;
58     struct lwkt_serialize *serializer;
59 } *intrec_t;
60 
61 struct intr_info {
62 	intrec_t	i_reclist;
63 	struct thread	*i_thread;	/* don't embed struct thread */
64 	struct random_softc i_random;
65 	long		i_count;	/* interrupts dispatched */
66 	int		i_running;
67 	short		i_mplock_required;
68 	short		i_flags;
69 	int		i_fast;
70 	int		i_slow;
71 	int		i_state;
72 	int		i_errorticks;
73 	unsigned long	i_straycount;
74 	int		i_cpuid;
75 	int		i_intr;
76 };
77 
78 struct intr_info_block {
79 	struct intr_info ary[MAXCPU][MAX_INTS];
80 };
81 
82 static struct intr_info_block *intr_block;
83 static struct intr_info *swi_info_ary[MAX_SOFTINTS];
84 
85 static int max_installed_hard_intr[MAXCPU];
86 
87 MALLOC_DEFINE(M_INTRMNG, "intrmng", "interrupt management");
88 
89 
90 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000
91 
92 /*
93  * Assert that callers into interrupt handlers don't return with
94  * dangling tokens, spinlocks, or mp locks.
95  */
96 #ifdef INVARIANTS
97 
98 #define TD_INVARIANTS_DECLARE   \
99         int spincount;          \
100         lwkt_tokref_t curstop
101 
102 #define TD_INVARIANTS_GET(td)                                   \
103         do {                                                    \
104                 spincount = (td)->td_gd->gd_spinlocks;		\
105                 curstop = (td)->td_toks_stop;                   \
106         } while(0)
107 
108 #define TD_INVARIANTS_TEST(td, name)                                    \
109         do {                                                            \
110                 KASSERT(spincount == (td)->td_gd->gd_spinlocks,		\
111                         ("spincount mismatch after interrupt handler %s", \
112                         name));                                         \
113                 KASSERT(curstop == (td)->td_toks_stop,                  \
114                         ("token count mismatch after interrupt handler %s", \
115                         name));                                         \
116         } while(0)
117 
118 #else
119 
120 /* !INVARIANTS */
121 
122 #define TD_INVARIANTS_DECLARE
123 #define TD_INVARIANTS_GET(td)
124 #define TD_INVARIANTS_TEST(td, name)
125 
126 #endif /* ndef INVARIANTS */
127 
128 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS);
129 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS);
130 static void emergency_intr_timer_callback(systimer_t, int, struct intrframe *);
131 static void ithread_handler(void *arg);
132 static void ithread_emergency(void *arg);
133 static void report_stray_interrupt(struct intr_info *info, const char *func);
134 static void int_moveto_destcpu(int *, int);
135 static void int_moveto_origcpu(int, int);
136 static void sched_ithd_intern(struct intr_info *info);
137 
138 static struct systimer emergency_intr_timer[MAXCPU];
139 static struct thread *emergency_intr_thread[MAXCPU];
140 
141 #define ISTATE_NOTHREAD		0
142 #define ISTATE_NORMAL		1
143 #define ISTATE_LIVELOCKED	2
144 
145 static int livelock_limit = 40000;
146 static int livelock_limit_hi = 120000;
147 static int livelock_lowater = 20000;
148 static int livelock_debug = -1;
149 SYSCTL_INT(_kern, OID_AUTO, livelock_limit,
150         CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit");
151 SYSCTL_INT(_kern, OID_AUTO, livelock_limit_hi,
152         CTLFLAG_RW, &livelock_limit_hi, 0,
153 	"Livelock interrupt rate limit (high frequency)");
154 SYSCTL_INT(_kern, OID_AUTO, livelock_lowater,
155         CTLFLAG_RW, &livelock_lowater, 0, "Livelock low-water mark restore");
156 SYSCTL_INT(_kern, OID_AUTO, livelock_debug,
157         CTLFLAG_RW, &livelock_debug, 0, "Livelock debug intr#");
158 
159 static int emergency_intr_enable = 0;	/* emergency interrupt polling */
160 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable);
161 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_enable, CTLTYPE_INT | CTLFLAG_RW,
162         0, 0, sysctl_emergency_enable, "I", "Emergency Interrupt Poll Enable");
163 
164 static int emergency_intr_freq = 10;	/* emergency polling frequency */
165 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq);
166 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_freq, CTLTYPE_INT | CTLFLAG_RW,
167         0, 0, sysctl_emergency_freq, "I", "Emergency Interrupt Poll Frequency");
168 
169 /*
170  * Sysctl support routines
171  */
172 static int
sysctl_emergency_enable(SYSCTL_HANDLER_ARGS)173 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS)
174 {
175 	int error, enabled, cpuid, freq, origcpu;
176 
177 	enabled = emergency_intr_enable;
178 	error = sysctl_handle_int(oidp, &enabled, 0, req);
179 	if (error || req->newptr == NULL)
180 		return error;
181 	emergency_intr_enable = enabled;
182 	if (emergency_intr_enable)
183 		freq = emergency_intr_freq;
184 	else
185 		freq = 1;
186 
187 	origcpu = mycpuid;
188 	for (cpuid = 0; cpuid < ncpus; ++cpuid) {
189 		lwkt_migratecpu(cpuid);
190 		systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq);
191 	}
192 	lwkt_migratecpu(origcpu);
193 	return 0;
194 }
195 
196 static int
sysctl_emergency_freq(SYSCTL_HANDLER_ARGS)197 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS)
198 {
199         int error, phz, cpuid, freq, origcpu;
200 
201         phz = emergency_intr_freq;
202         error = sysctl_handle_int(oidp, &phz, 0, req);
203         if (error || req->newptr == NULL)
204                 return error;
205         if (phz <= 0)
206                 return EINVAL;
207         else if (phz > EMERGENCY_INTR_POLLING_FREQ_MAX)
208                 phz = EMERGENCY_INTR_POLLING_FREQ_MAX;
209 
210         emergency_intr_freq = phz;
211 	if (emergency_intr_enable)
212 		freq = emergency_intr_freq;
213 	else
214 		freq = 1;
215 
216 	origcpu = mycpuid;
217 	for (cpuid = 0; cpuid < ncpus; ++cpuid) {
218 		lwkt_migratecpu(cpuid);
219 		systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq);
220 	}
221 	lwkt_migratecpu(origcpu);
222         return 0;
223 }
224 
225 /*
226  * Register an SWI or INTerrupt handler.
227  */
228 void *
register_swi(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)229 register_swi(int intr, inthand2_t *handler, void *arg, const char *name,
230 		struct lwkt_serialize *serializer, int cpuid)
231 {
232     if (intr < FIRST_SOFTINT || intr >= MAX_INTS)
233 	panic("register_swi: bad intr %d", intr);
234 
235     if (cpuid < 0)
236 	cpuid = intr % ncpus;
237     return(register_int(intr, handler, arg, name, serializer, 0, cpuid));
238 }
239 
240 void *
register_swi_mp(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)241 register_swi_mp(int intr, inthand2_t *handler, void *arg, const char *name,
242 		struct lwkt_serialize *serializer, int cpuid)
243 {
244     if (intr < FIRST_SOFTINT || intr >= MAX_INTS)
245 	panic("register_swi: bad intr %d", intr);
246 
247     if (cpuid < 0)
248 	cpuid = intr % ncpus;
249     return(register_int(intr, handler, arg, name, serializer,
250 			INTR_MPSAFE, cpuid));
251 }
252 
253 void *
register_int(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags,int cpuid)254 register_int(int intr, inthand2_t *handler, void *arg, const char *name,
255 		struct lwkt_serialize *serializer, int intr_flags, int cpuid)
256 {
257     struct intr_info *info;
258     struct intrec **list;
259     intrec_t rec = NULL;
260     int orig_cpuid;
261 
262     KKASSERT(cpuid >= 0 && cpuid < ncpus);
263 
264     if (intr < 0 || intr >= MAX_INTS)
265 	panic("register_int: bad intr %d", intr);
266     if (name == NULL)
267 	name = "???";
268     info = &intr_block->ary[cpuid][intr];
269 
270     int_moveto_destcpu(&orig_cpuid, cpuid);
271 
272     /*
273      * This intr has been registered as exclusive one, so
274      * it can't shared.
275      */
276     if (info->i_flags & INTR_EXCL)
277 	goto done;
278 
279     /*
280      * This intr has been registered as shared one, so it
281      * can't be used for exclusive handler.
282      */
283     list = &info->i_reclist;
284     if ((intr_flags & INTR_EXCL) && *list != NULL)
285 	goto done;
286 
287     /*
288      * Construct an interrupt handler record
289      */
290     rec = kmalloc(sizeof(struct intrec), M_DEVBUF, M_INTWAIT);
291     rec->name = kmalloc(strlen(name) + 1, M_DEVBUF, M_INTWAIT);
292     strcpy(rec->name, name);
293 
294     rec->info = info;
295     rec->handler = handler;
296     rec->argument = arg;
297     rec->intr = intr;
298     rec->intr_flags = intr_flags;
299     rec->next = NULL;
300     rec->serializer = serializer;
301 
302     /*
303      * Create an emergency polling thread and set up a systimer to wake
304      * it up.  objcache isn't operational yet so use kmalloc.
305      *
306      * objcache may not be operational yet, use kmalloc().
307      */
308     if (emergency_intr_thread[cpuid] == NULL) {
309 	emergency_intr_thread[cpuid] = kmalloc(sizeof(struct thread), M_DEVBUF,
310 					       M_INTWAIT | M_ZERO);
311 	lwkt_create(ithread_emergency, NULL, NULL,
312 		    emergency_intr_thread[cpuid],
313 		    TDF_NOSTART | TDF_INTTHREAD, cpuid, "ithreadE %d",
314 		    cpuid);
315 	systimer_init_periodic_nq(&emergency_intr_timer[cpuid],
316 		    emergency_intr_timer_callback,
317 		    emergency_intr_thread[cpuid],
318 		    (emergency_intr_enable ? emergency_intr_freq : 1));
319     }
320 
321     /*
322      * Create an interrupt thread if necessary, leave it in an unscheduled
323      * state.
324      */
325     if (info->i_state == ISTATE_NOTHREAD) {
326 	info->i_state = ISTATE_NORMAL;
327 	info->i_thread = kmalloc(sizeof(struct thread), M_DEVBUF,
328 				 M_INTWAIT | M_ZERO);
329 	lwkt_create(ithread_handler, (void *)(intptr_t)intr, NULL,
330 		    info->i_thread, TDF_NOSTART | TDF_INTTHREAD, cpuid,
331 		    "ithread%d %d", intr, cpuid);
332 	if (intr >= FIRST_SOFTINT)
333 	    lwkt_setpri(info->i_thread, TDPRI_SOFT_NORM);
334 	else
335 	    lwkt_setpri(info->i_thread, TDPRI_INT_MED);
336 	info->i_thread->td_preemptable = lwkt_preempt;
337     }
338 
339     /*
340      * Keep track of how many fast and slow interrupts we have.
341      * Set i_mplock_required if any handler in the chain requires
342      * the MP lock to operate.
343      */
344     if ((intr_flags & INTR_MPSAFE) == 0) {
345 	info->i_mplock_required = 1;
346 	kprintf("interrupt uses mplock: %s\n", name);
347     }
348     if (intr_flags & INTR_CLOCK) {
349 	atomic_set_int(&info->i_thread->td_flags, TDF_CLKTHREAD);
350 	++info->i_fast;
351     } else {
352 	++info->i_slow;
353     }
354 
355     info->i_flags |= (intr_flags & INTR_EXCL);
356     if (info->i_slow + info->i_fast == 1 && (intr_flags & INTR_HIFREQ)) {
357 	/*
358 	 * Allow high frequency interrupt, if this intr is not
359 	 * shared yet.
360 	 */
361 	info->i_flags |= INTR_HIFREQ;
362     } else {
363 	info->i_flags &= ~INTR_HIFREQ;
364     }
365 
366     /*
367      * Enable random number generation keying off of this interrupt.
368      */
369     if ((intr_flags & INTR_NOENTROPY) == 0 && info->i_random.sc_enabled == 0) {
370 	info->i_random.sc_enabled = 1;
371 	info->i_random.sc_intr = intr;
372     }
373 
374     /*
375      * Add the record to the interrupt list.
376      */
377     crit_enter();
378     while (*list != NULL)
379 	list = &(*list)->next;
380     *list = rec;
381     crit_exit();
382 
383     /*
384      * Update max_installed_hard_intr to make the emergency intr poll
385      * a bit more efficient.
386      */
387     if (intr < FIRST_SOFTINT) {
388 	if (max_installed_hard_intr[cpuid] <= intr)
389 	    max_installed_hard_intr[cpuid] = intr + 1;
390     }
391 
392     if (intr >= FIRST_SOFTINT)
393 	swi_info_ary[intr - FIRST_SOFTINT] = info;
394 
395     /*
396      * Setup the machine level interrupt vector
397      */
398     if (intr < FIRST_SOFTINT && info->i_slow + info->i_fast == 1)
399 	machintr_intr_setup(intr, intr_flags);
400 
401 done:
402     int_moveto_origcpu(orig_cpuid, cpuid);
403     return(rec);
404 }
405 
406 void
unregister_swi(void * id,int intr,int cpuid)407 unregister_swi(void *id, int intr, int cpuid)
408 {
409     if (cpuid < 0)
410 	cpuid = intr % ncpus;
411 
412     unregister_int(id, cpuid);
413 }
414 
415 void
unregister_int(void * id,int cpuid)416 unregister_int(void *id, int cpuid)
417 {
418     struct intr_info *info;
419     struct intrec **list;
420     intrec_t rec;
421     int intr, orig_cpuid;
422 
423     KKASSERT(cpuid >= 0 && cpuid < ncpus);
424 
425     intr = ((intrec_t)id)->intr;
426 
427     if (intr < 0 || intr >= MAX_INTS)
428 	panic("register_int: bad intr %d", intr);
429 
430     info = &intr_block->ary[cpuid][intr];
431 
432     int_moveto_destcpu(&orig_cpuid, cpuid);
433 
434     /*
435      * Remove the interrupt descriptor, adjust the descriptor count,
436      * and teardown the machine level vector if this was the last interrupt.
437      */
438     crit_enter();
439     list = &info->i_reclist;
440     while ((rec = *list) != NULL) {
441 	if (rec == id)
442 	    break;
443 	list = &rec->next;
444     }
445     if (rec) {
446 	intrec_t rec0;
447 
448 	*list = rec->next;
449 	if (rec->intr_flags & INTR_CLOCK)
450 	    --info->i_fast;
451 	else
452 	    --info->i_slow;
453 	if (intr < FIRST_SOFTINT && info->i_fast + info->i_slow == 0)
454 	    machintr_intr_teardown(intr);
455 
456 	/*
457 	 * Clear i_mplock_required if no handlers in the chain require the
458 	 * MP lock.
459 	 */
460 	for (rec0 = info->i_reclist; rec0; rec0 = rec0->next) {
461 	    if ((rec0->intr_flags & INTR_MPSAFE) == 0)
462 		break;
463 	}
464 	if (rec0 == NULL)
465 	    info->i_mplock_required = 0;
466     }
467 
468     if (info->i_reclist == NULL) {
469 	info->i_flags = 0;
470 	if (intr >= FIRST_SOFTINT)
471 	    swi_info_ary[intr - FIRST_SOFTINT] = NULL;
472     } else if (info->i_fast + info->i_slow == 1 &&
473 	(info->i_reclist->intr_flags & INTR_HIFREQ)) {
474 	/* Unshared high frequency interrupt. */
475 	info->i_flags |= INTR_HIFREQ;
476     }
477 
478     crit_exit();
479 
480     int_moveto_origcpu(orig_cpuid, cpuid);
481 
482     /*
483      * Free the record.
484      */
485     if (rec != NULL) {
486 	kfree(rec->name, M_DEVBUF);
487 	kfree(rec, M_DEVBUF);
488     } else {
489 	kprintf("warning: unregister_int: int %d handler for %s not found\n",
490 		intr, ((intrec_t)id)->name);
491     }
492 }
493 
494 long
get_interrupt_counter(int intr,int cpuid)495 get_interrupt_counter(int intr, int cpuid)
496 {
497     struct intr_info *info;
498 
499     KKASSERT(cpuid >= 0 && cpuid < ncpus);
500 
501     if (intr < 0 || intr >= MAX_INTS)
502 	panic("register_int: bad intr %d", intr);
503     info = &intr_block->ary[cpuid][intr];
504     return(info->i_count);
505 }
506 
507 void
register_randintr(int intr)508 register_randintr(int intr)
509 {
510     struct intr_info *info;
511     int cpuid;
512 
513     if (intr < 0 || intr >= MAX_INTS)
514 	panic("register_randintr: bad intr %d", intr);
515 
516     for (cpuid = 0; cpuid < ncpus; ++cpuid) {
517 	info = &intr_block->ary[cpuid][intr];
518 	info->i_random.sc_intr = intr;
519 	info->i_random.sc_enabled = 1;
520     }
521 }
522 
523 void
unregister_randintr(int intr)524 unregister_randintr(int intr)
525 {
526     struct intr_info *info;
527     int cpuid;
528 
529     if (intr < 0 || intr >= MAX_INTS)
530 	panic("register_swi: bad intr %d", intr);
531 
532     for (cpuid = 0; cpuid < ncpus; ++cpuid) {
533 	info = &intr_block->ary[cpuid][intr];
534 	info->i_random.sc_enabled = -1;
535     }
536 }
537 
538 int
next_registered_randintr(int intr)539 next_registered_randintr(int intr)
540 {
541     struct intr_info *info;
542 
543     if (intr < 0 || intr >= MAX_INTS)
544 	panic("register_swi: bad intr %d", intr);
545 
546     while (intr < MAX_INTS) {
547 	int cpuid;
548 
549 	for (cpuid = 0; cpuid < ncpus; ++cpuid) {
550 	    info = &intr_block->ary[cpuid][intr];
551 	    if (info->i_random.sc_enabled > 0)
552 		return intr;
553 	}
554 	++intr;
555     }
556     return intr;
557 }
558 
559 /*
560  * Dispatch an interrupt.  If there's nothing to do we have a stray
561  * interrupt and can just return, leaving the interrupt masked.
562  *
563  * We need to schedule the interrupt and set its i_running bit.  If
564  * we are not on the interrupt thread's cpu we have to send a message
565  * to the correct cpu that will issue the desired action (interlocking
566  * with the interrupt thread's critical section).  We do NOT attempt to
567  * reschedule interrupts whos i_running bit is already set because
568  * this would prematurely wakeup a livelock-limited interrupt thread.
569  *
570  * i_running is only tested/set on the same cpu as the interrupt thread.
571  *
572  * We are NOT in a critical section, which will allow the scheduled
573  * interrupt to preempt us.  The MP lock might *NOT* be held here.
574  */
575 static void
sched_ithd_remote(void * arg)576 sched_ithd_remote(void *arg)
577 {
578     sched_ithd_intern(arg);
579 }
580 
581 static void
sched_ithd_intern(struct intr_info * info)582 sched_ithd_intern(struct intr_info *info)
583 {
584     ++info->i_count;
585     if (info->i_state != ISTATE_NOTHREAD) {
586 	if (info->i_reclist == NULL) {
587 	    report_stray_interrupt(info, "sched_ithd");
588 	} else {
589 	    if (info->i_thread->td_gd == mycpu) {
590 		if (info->i_running == 0) {
591 		    info->i_running = 1;
592 		    if (info->i_state != ISTATE_LIVELOCKED)
593 			lwkt_schedule(info->i_thread); /* MIGHT PREEMPT */
594 		}
595 	    } else {
596 		lwkt_send_ipiq(info->i_thread->td_gd, sched_ithd_remote, info);
597 	    }
598 	}
599     } else {
600 	report_stray_interrupt(info, "sched_ithd");
601     }
602 }
603 
604 void
sched_ithd_soft(int intr)605 sched_ithd_soft(int intr)
606 {
607 	struct intr_info *info;
608 
609 	KKASSERT(intr >= FIRST_SOFTINT && intr < MAX_INTS);
610 
611 	info = swi_info_ary[intr - FIRST_SOFTINT];
612 	if (info != NULL) {
613 		sched_ithd_intern(info);
614 	} else {
615 		kprintf("unregistered softint %d got scheduled on cpu%d\n",
616 		    intr, mycpuid);
617 	}
618 }
619 
620 void
sched_ithd_hard(int intr)621 sched_ithd_hard(int intr)
622 {
623 	KKASSERT(intr >= 0 && intr < MAX_HARDINTS);
624 	sched_ithd_intern(&intr_block->ary[mycpuid][intr]);
625 }
626 
627 #ifdef _KERNEL_VIRTUAL
628 
629 void
sched_ithd_hard_virtual(int intr)630 sched_ithd_hard_virtual(int intr)
631 {
632 	KKASSERT(intr >= 0 && intr < MAX_HARDINTS);
633 	sched_ithd_intern(&intr_block->ary[0][intr]);
634 }
635 
636 void *
register_int_virtual(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags)637 register_int_virtual(int intr, inthand2_t *handler, void *arg, const char *name,
638     struct lwkt_serialize *serializer, int intr_flags)
639 {
640 	return register_int(intr, handler, arg, name, serializer, intr_flags, 0);
641 }
642 
643 void
unregister_int_virtual(void * id)644 unregister_int_virtual(void *id)
645 {
646 	unregister_int(id, 0);
647 }
648 
649 #endif	/* _KERN_VIRTUAL */
650 
651 static void
report_stray_interrupt(struct intr_info * info,const char * func)652 report_stray_interrupt(struct intr_info *info, const char *func)
653 {
654 	++info->i_straycount;
655 	if (info->i_straycount < 10) {
656 		if (info->i_errorticks == ticks)
657 			return;
658 		info->i_errorticks = ticks;
659 		kprintf("%s: stray interrupt %d on cpu%d\n",
660 		    func, info->i_intr, mycpuid);
661 	} else if (info->i_straycount == 10) {
662 		kprintf("%s: %ld stray interrupts %d on cpu%d - "
663 			"there will be no further reports\n", func,
664 			info->i_straycount, info->i_intr, mycpuid);
665 	}
666 }
667 
668 /*
669  * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL
670  * might not be held).
671  */
672 static void
ithread_livelock_wakeup(systimer_t st,int in_ipi __unused,struct intrframe * frame __unused)673 ithread_livelock_wakeup(systimer_t st, int in_ipi __unused,
674     struct intrframe *frame __unused)
675 {
676     struct intr_info *info;
677 
678     info = &intr_block->ary[mycpuid][(int)(intptr_t)st->data];
679     if (info->i_state != ISTATE_NOTHREAD)
680 	lwkt_schedule(info->i_thread);
681 }
682 
683 /*
684  * Schedule ithread within fast intr handler
685  *
686  * Temporarily bump the current thread's td_nest_count to prevent deep
687  * preemptions and splz/doreti stacks.
688  */
689 static __inline void
ithread_fast_sched(int intr,thread_t td)690 ithread_fast_sched(int intr, thread_t td)
691 {
692     ++td->td_nest_count;
693     crit_exit_quick(td);
694     sched_ithd_hard(intr);
695     crit_enter_quick(td);
696     --td->td_nest_count;
697 }
698 
699 /*
700  * This function is called directly from the ICU or APIC vector code assembly
701  * to process an interrupt.  The critical section and interrupt deferral
702  * checks have already been done but the function is entered WITHOUT
703  * a critical section held.  The BGL may or may not be held.
704  *
705  * Must return non-zero if we do not want the vector code to re-enable
706  * the interrupt (which we don't if we have to schedule the interrupt)
707  */
708 int ithread_fast_handler(struct intrframe *frame);
709 
710 int
ithread_fast_handler(struct intrframe * frame)711 ithread_fast_handler(struct intrframe *frame)
712 {
713     int intr;
714     struct intr_info *info;
715     struct intrec **list;
716     int must_schedule;
717     int got_mplock;
718     TD_INVARIANTS_DECLARE;
719     intrec_t rec, nrec;
720     globaldata_t gd;
721     thread_t td;
722 
723     intr = frame->if_vec;
724     gd = mycpu;
725     td = curthread;
726 
727     /* We must be in critical section. */
728     KKASSERT(td->td_critcount);
729 
730     /* Race condition during early boot */
731     if (intr_block == NULL)
732 	return 0;
733 
734     info = &intr_block->ary[mycpuid][intr];
735 
736     /*
737      * If we are not processing any FAST interrupts, just schedule the thing.
738      */
739     if (info->i_fast == 0) {
740     	++gd->gd_cnt.v_intr;
741 	ithread_fast_sched(intr, td);
742 	return(1);
743     }
744 
745     /*
746      * This should not normally occur since interrupts ought to be
747      * masked if the ithread has been scheduled or is running.
748      */
749     if (info->i_running)
750 	return(1);
751 
752     /*
753      * Bump the interrupt nesting level to process any FAST interrupts.
754      * Obtain the MP lock as necessary.  If the MP lock cannot be obtained,
755      * schedule the interrupt thread to deal with the issue instead.
756      *
757      * To reduce overhead, just leave the MP lock held once it has been
758      * obtained.
759      */
760     ++gd->gd_intr_nesting_level;
761     ++gd->gd_cnt.v_intr;
762     must_schedule = info->i_slow;
763     got_mplock = 0;
764 
765     TD_INVARIANTS_GET(td);
766     list = &info->i_reclist;
767 
768     for (rec = *list; rec; rec = nrec) {
769 	/* rec may be invalid after call */
770 	nrec = rec->next;
771 
772 	if (rec->intr_flags & INTR_CLOCK) {
773 	    if ((rec->intr_flags & INTR_MPSAFE) == 0 && got_mplock == 0) {
774 		if (try_mplock() == 0) {
775 		    /* Couldn't get the MP lock; just schedule it. */
776 		    must_schedule = 1;
777 		    break;
778 		}
779 		got_mplock = 1;
780 	    }
781 	    if (rec->serializer) {
782 		must_schedule += lwkt_serialize_handler_try(
783 					rec->serializer, rec->handler,
784 					rec->argument, frame);
785 	    } else {
786 		rec->handler(rec->argument, frame);
787 	    }
788 	    TD_INVARIANTS_TEST(td, rec->name);
789 	}
790     }
791 
792     /*
793      * Cleanup
794      */
795     --gd->gd_intr_nesting_level;
796     if (got_mplock)
797 	rel_mplock();
798 
799     /*
800      * If we had a problem, or mixed fast and slow interrupt handlers are
801      * registered, schedule the ithread to catch the missed records (it
802      * will just re-run all of them).  A return value of 0 indicates that
803      * all handlers have been run and the interrupt can be re-enabled, and
804      * a non-zero return indicates that the interrupt thread controls
805      * re-enablement.
806      */
807     if (must_schedule > 0)
808 	ithread_fast_sched(intr, td);
809     else if (must_schedule == 0)
810 	++info->i_count;
811     return(must_schedule);
812 }
813 
814 /*
815  * Interrupt threads run this as their main loop.
816  *
817  * The handler begins execution outside a critical section and no MP lock.
818  *
819  * The i_running state starts at 0.  When an interrupt occurs, the hardware
820  * interrupt is disabled and sched_ithd_hard().  The HW interrupt remains
821  * disabled until all routines have run.  We then call machintr_intr_enable()
822  * to reenable the HW interrupt and deschedule us until the next interrupt.
823  *
824  * We are responsible for atomically checking i_running.  i_running for our
825  * irq is only set in the context of our cpu, so a critical section is a
826  * sufficient interlock.
827  */
828 #define LIVELOCK_TIMEFRAME(freq)	((freq) >> 2)	/* 1/4 second */
829 
830 static void
ithread_handler(void * arg)831 ithread_handler(void *arg)
832 {
833     struct intr_info *info;
834     int use_limit;
835     uint32_t lseconds;
836     int intr, cpuid = mycpuid;
837     int mpheld;
838     struct intrec **list;
839     intrec_t rec, nrec;
840     globaldata_t gd;
841     struct systimer ill_timer;	/* enforced freq. timer */
842     u_int ill_count;		/* interrupt livelock counter */
843     int upper_limit;		/* interrupt livelock upper limit */
844     TD_INVARIANTS_DECLARE;
845 
846     ill_count = 0;
847     intr = (int)(intptr_t)arg;
848     info = &intr_block->ary[cpuid][intr];
849     list = &info->i_reclist;
850 
851     /*
852      * The loop must be entered with one critical section held.  The thread
853      * does not hold the mplock on startup.
854      */
855     gd = mycpu;
856     lseconds = gd->gd_time_seconds;
857     crit_enter_gd(gd);
858     mpheld = 0;
859 
860     for (;;) {
861 	/*
862 	 * The chain is only considered MPSAFE if all its interrupt handlers
863 	 * are MPSAFE.  However, if intr_mpsafe has been turned off we
864 	 * always operate with the BGL.
865 	 */
866 	if (info->i_mplock_required != mpheld) {
867 	    if (info->i_mplock_required) {
868 		KKASSERT(mpheld == 0);
869 		get_mplock();
870 		mpheld = 1;
871 	    } else {
872 		KKASSERT(mpheld != 0);
873 		rel_mplock();
874 		mpheld = 0;
875 	    }
876 	}
877 
878 	TD_INVARIANTS_GET(gd->gd_curthread);
879 
880 	/*
881 	 * If an interrupt is pending, clear i_running and execute the
882 	 * handlers.  Note that certain types of interrupts can re-trigger
883 	 * and set i_running again.
884 	 *
885 	 * Each handler is run in a critical section.  Note that we run both
886 	 * FAST and SLOW designated service routines.
887 	 */
888 	if (info->i_running) {
889 	    ++ill_count;
890 	    info->i_running = 0;
891 
892 	    if (*list == NULL)
893 		report_stray_interrupt(info, "ithread_handler");
894 
895 	    for (rec = *list; rec; rec = nrec) {
896 		/* rec may be invalid after call */
897 		nrec = rec->next;
898 		if (rec->handler == NULL) {
899 		    kprintf("NULL HANDLER %s\n", rec->name);
900 		} else
901 		if (rec->serializer) {
902 		    lwkt_serialize_handler_call(rec->serializer, rec->handler,
903 						rec->argument, NULL);
904 		} else {
905 		    rec->handler(rec->argument, NULL);
906 		}
907 		TD_INVARIANTS_TEST(gd->gd_curthread, rec->name);
908 	    }
909 	}
910 
911 	/*
912 	 * This is our interrupt hook to add rate randomness to the random
913 	 * number generator.
914 	 */
915 	if (info->i_random.sc_enabled > 0)
916 	    add_interrupt_randomness(intr);
917 
918 	/*
919 	 * Unmask the interrupt to allow it to trigger again.  This only
920 	 * applies to certain types of interrupts (typ level interrupts).
921 	 * This can result in the interrupt retriggering, but the retrigger
922 	 * will not be processed until we cycle our critical section.
923 	 *
924 	 * Only unmask interrupts while handlers are installed.  It is
925 	 * possible to hit a situation where no handlers are installed
926 	 * due to a device driver livelocking and then tearing down its
927 	 * interrupt on close (the parallel bus being a good example).
928 	 */
929 	if (intr < FIRST_SOFTINT && *list)
930 	    machintr_intr_enable(intr);
931 
932 	/*
933 	 * Do a quick exit/enter to catch any higher-priority interrupt
934 	 * sources, such as the statclock, so thread time accounting
935 	 * will still work.  This may also cause an interrupt to re-trigger.
936 	 */
937 	crit_exit_gd(gd);
938 	crit_enter_gd(gd);
939 
940 	/*
941 	 * LIVELOCK STATE MACHINE
942 	 */
943 	switch(info->i_state) {
944 	case ISTATE_NORMAL:
945 	    /*
946 	     * Reset the count each second.
947 	     */
948 	    if (lseconds != gd->gd_time_seconds) {
949 		lseconds = gd->gd_time_seconds;
950 		ill_count = 0;
951 	    }
952 
953 	    /*
954 	     * If we did not exceed the frequency limit, we are done.
955 	     * If the interrupt has not retriggered we deschedule ourselves.
956 	     */
957 	    if (info->i_flags & INTR_HIFREQ)
958 		upper_limit = livelock_limit_hi;
959 	    else
960 		upper_limit = livelock_limit;
961 	    if (ill_count <= upper_limit) {
962 		if (info->i_running == 0) {
963 		    lwkt_deschedule_self(gd->gd_curthread);
964 		    lwkt_switch();
965 		}
966 		break;
967 	    }
968 
969 	    /*
970 	     * Otherwise we are livelocked.  Set up a periodic systimer
971 	     * to wake the thread up at the limit frequency.
972 	     */
973 	    kprintf("intr %d on cpu%d at %d/%d hz, livelocked limit engaged!\n",
974 		    intr, cpuid, ill_count, upper_limit);
975 	    info->i_state = ISTATE_LIVELOCKED;
976 	    if ((use_limit = upper_limit) < 100)
977 		use_limit = 100;
978 	    else if (use_limit > 500000)
979 		use_limit = 500000;
980 	    systimer_init_periodic_nq(&ill_timer, ithread_livelock_wakeup,
981 				      (void *)(intptr_t)intr, use_limit);
982 	    /* fall through */
983 	case ISTATE_LIVELOCKED:
984 	    /*
985 	     * Wait for our periodic timer to go off.  Since the interrupt
986 	     * has re-armed it can still set i_running, but it will not
987 	     * reschedule us while we are in a livelocked state.
988 	     */
989 	    lwkt_deschedule_self(gd->gd_curthread);
990 	    lwkt_switch();
991 
992 	    /*
993 	     * Check once a second to see if the livelock condition no
994 	     * longer applies.
995 	     */
996 	    if (lseconds != gd->gd_time_seconds) {
997 		lseconds = gd->gd_time_seconds;
998 		if (ill_count < livelock_lowater) {
999 		    info->i_state = ISTATE_NORMAL;
1000 		    systimer_del(&ill_timer);
1001 		    kprintf("intr %d on cpu%d at %d/%d hz, livelock removed\n",
1002 			    intr, cpuid, ill_count, livelock_lowater);
1003 		} else if (livelock_debug == intr ||
1004 			   (bootverbose && cold)) {
1005 		    kprintf("intr %d on cpu%d at %d/%d hz, in livelock\n",
1006 			    intr, cpuid, ill_count, livelock_lowater);
1007 		}
1008 		ill_count = 0;
1009 	    }
1010 	    break;
1011 	}
1012     }
1013     /* NOT REACHED */
1014 }
1015 
1016 /*
1017  * Emergency interrupt polling thread.  The thread begins execution
1018  * outside a critical section with the BGL held.
1019  *
1020  * If emergency interrupt polling is enabled, this thread will
1021  * execute all system interrupts not marked INTR_NOPOLL at the
1022  * specified polling frequency.
1023  *
1024  * WARNING!  This thread runs *ALL* interrupt service routines that
1025  * are not marked INTR_NOPOLL, which basically means everything except
1026  * the 8254 clock interrupt and the ATA interrupt.  It has very high
1027  * overhead and should only be used in situations where the machine
1028  * cannot otherwise be made to work.  Due to the severe performance
1029  * degredation, it should not be enabled on production machines.
1030  */
1031 static void
ithread_emergency(void * arg __unused)1032 ithread_emergency(void *arg __unused)
1033 {
1034     globaldata_t gd = mycpu;
1035     struct intr_info *info;
1036     intrec_t rec, nrec;
1037     int intr, cpuid = mycpuid;
1038     TD_INVARIANTS_DECLARE;
1039 
1040     get_mplock();
1041     crit_enter_gd(gd);
1042     TD_INVARIANTS_GET(gd->gd_curthread);
1043 
1044     for (;;) {
1045 	for (intr = 0; intr < max_installed_hard_intr[cpuid]; ++intr) {
1046 	    info = &intr_block->ary[cpuid][intr];
1047 	    for (rec = info->i_reclist; rec; rec = nrec) {
1048 		/* rec may be invalid after call */
1049 		nrec = rec->next;
1050 		if ((rec->intr_flags & INTR_NOPOLL) == 0) {
1051 		    if (rec->serializer) {
1052 			lwkt_serialize_handler_try(rec->serializer,
1053 						rec->handler, rec->argument, NULL);
1054 		    } else {
1055 			rec->handler(rec->argument, NULL);
1056 		    }
1057 		    TD_INVARIANTS_TEST(gd->gd_curthread, rec->name);
1058 		}
1059 	    }
1060 	}
1061 	lwkt_deschedule_self(gd->gd_curthread);
1062 	lwkt_switch();
1063     }
1064     /* NOT REACHED */
1065 }
1066 
1067 /*
1068  * Systimer callback - schedule the emergency interrupt poll thread
1069  * 		       if emergency polling is enabled.
1070  */
1071 static
1072 void
emergency_intr_timer_callback(systimer_t info,int in_ipi __unused,struct intrframe * frame __unused)1073 emergency_intr_timer_callback(systimer_t info, int in_ipi __unused,
1074     struct intrframe *frame __unused)
1075 {
1076     if (emergency_intr_enable)
1077 	lwkt_schedule(info->data);
1078 }
1079 
1080 /*
1081  * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
1082  * The data for this machine dependent, and the declarations are in machine
1083  * dependent code.  The layout of intrnames and intrcnt however is machine
1084  * independent.
1085  *
1086  * We do not know the length of intrcnt and intrnames at compile time, so
1087  * calculate things at run time.
1088  */
1089 
1090 static int
sysctl_intrnames(SYSCTL_HANDLER_ARGS)1091 sysctl_intrnames(SYSCTL_HANDLER_ARGS)
1092 {
1093     struct intr_info *info;
1094     intrec_t rec;
1095     int error = 0;
1096     int len;
1097     int intr, cpuid;
1098     char buf[64];
1099 
1100     for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1101 	for (intr = 0; error == 0 && intr < MAX_INTS; ++intr) {
1102 	    info = &intr_block->ary[cpuid][intr];
1103 
1104 	    len = 0;
1105 	    buf[0] = 0;
1106 	    for (rec = info->i_reclist; rec; rec = rec->next) {
1107 		ksnprintf(buf + len, sizeof(buf) - len, "%s%s",
1108 		    (len ? "/" : ""), rec->name);
1109 		len += strlen(buf + len);
1110 	    }
1111 	    if (len == 0) {
1112 		ksnprintf(buf, sizeof(buf), "irq%d", intr);
1113 		len = strlen(buf);
1114 	    }
1115 	    error = SYSCTL_OUT(req, buf, len + 1);
1116 	}
1117     }
1118     return (error);
1119 }
1120 
1121 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
1122 	NULL, 0, sysctl_intrnames, "", "Interrupt Names");
1123 
1124 static int
sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS)1125 sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS)
1126 {
1127     struct intr_info *info;
1128     int error = 0;
1129     int intr, cpuid;
1130 
1131     for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1132 	for (intr = 0; intr < MAX_INTS; ++intr) {
1133 	    info = &intr_block->ary[cpuid][intr];
1134 
1135 	    error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count));
1136 	    if (error)
1137 		goto failed;
1138 	}
1139     }
1140 failed:
1141     return(error);
1142 }
1143 
1144 SYSCTL_PROC(_hw, OID_AUTO, intrcnt_all, CTLTYPE_OPAQUE | CTLFLAG_RD,
1145 	NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts");
1146 
1147 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
1148 	NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts");
1149 
1150 static void
int_moveto_destcpu(int * orig_cpuid0,int cpuid)1151 int_moveto_destcpu(int *orig_cpuid0, int cpuid)
1152 {
1153     int orig_cpuid = mycpuid;
1154 
1155     if (cpuid != orig_cpuid)
1156 	lwkt_migratecpu(cpuid);
1157 
1158     *orig_cpuid0 = orig_cpuid;
1159 }
1160 
1161 static void
int_moveto_origcpu(int orig_cpuid,int cpuid)1162 int_moveto_origcpu(int orig_cpuid, int cpuid)
1163 {
1164     if (cpuid != orig_cpuid)
1165 	lwkt_migratecpu(orig_cpuid);
1166 }
1167 
1168 static void
intr_init(void * dummy __unused)1169 intr_init(void *dummy __unused)
1170 {
1171 	int cpuid;
1172 
1173 	kprintf("Initialize MI interrupts for %d cpus\n", ncpus);
1174 
1175 	intr_block = kmalloc(offsetof(struct intr_info_block, ary[ncpus][0]),
1176 			     M_INTRMNG, M_INTWAIT | M_ZERO);
1177 
1178 	for (cpuid = 0; cpuid < ncpus; ++cpuid) {
1179 		int intr;
1180 
1181 		for (intr = 0; intr < MAX_INTS; ++intr) {
1182 			struct intr_info *info = &intr_block->ary[cpuid][intr];
1183 
1184 			info->i_cpuid = cpuid;
1185 			info->i_intr = intr;
1186 		}
1187 	}
1188 }
1189 SYSINIT(intr_init, SI_BOOT2_FINISH_PIC, SI_ORDER_ANY, intr_init, NULL);
1190