Update the README file with useful information about ACPI.
[dragonfly.git] / sys / kern / kern_intr.c
CommitLineData
984263bc 1/*
033a4603 2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
ef0fdad1 3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> All rights reserved.
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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 $
033a4603 27 * $DragonFly: src/sys/kern/kern_intr.c,v 1.17 2004/06/28 02:57:11 drhodus Exp $
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28 *
29 */
30
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31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/malloc.h>
34#include <sys/kernel.h>
35#include <sys/sysctl.h>
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36#include <sys/thread.h>
37#include <sys/proc.h>
38#include <sys/thread2.h>
7e071e7a 39#include <sys/random.h>
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40
41#include <machine/ipl.h>
42
43#include <sys/interrupt.h>
44
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45typedef struct intrec {
46 struct intrec *next;
47 inthand2_t *handler;
48 void *argument;
49 const char *name;
50 int intr;
51} intrec_t;
52
53static intrec_t *intlists[NHWI+NSWI];
54static thread_t ithreads[NHWI+NSWI];
55static struct thread ithread_ary[NHWI+NSWI];
7e071e7a 56static struct random_softc irandom_ary[NHWI+NSWI];
96728c05 57static int irunning[NHWI+NSWI];
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58static u_int ill_count[NHWI+NSWI]; /* interrupt livelock counter */
59static u_int ill_ticks[NHWI+NSWI]; /* track elapsed to calculate freq */
60static u_int ill_delta[NHWI+NSWI]; /* track elapsed to calculate freq */
37d44089 61static int ill_state[NHWI+NSWI]; /* current state */
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62static struct systimer ill_timer[NHWI+NSWI]; /* enforced freq. timer */
63static struct systimer ill_rtimer[NHWI+NSWI]; /* recovery timer */
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64
65#define LIVELOCK_NONE 0
66#define LIVELOCK_LIMITED 1
67
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68static int livelock_limit = 50000;
69static int livelock_fallback = 20000;
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70SYSCTL_INT(_kern, OID_AUTO, livelock_limit,
71 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit");
72SYSCTL_INT(_kern, OID_AUTO, livelock_fallback,
73 CTLFLAG_RW, &livelock_fallback, 0, "Livelock interrupt fallback rate");
984263bc 74
ef0fdad1 75static void ithread_handler(void *arg);
984263bc 76
96728c05 77thread_t
ef0fdad1 78register_swi(int intr, inthand2_t *handler, void *arg, const char *name)
984263bc 79{
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80 if (intr < NHWI || intr >= NHWI + NSWI)
81 panic("register_swi: bad intr %d", intr);
96728c05 82 return(register_int(intr, handler, arg, name));
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83}
84
96728c05 85thread_t
ef0fdad1 86register_int(int intr, inthand2_t *handler, void *arg, const char *name)
984263bc 87{
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88 intrec_t **list;
89 intrec_t *rec;
90 thread_t td;
91
93781523 92 if (intr < 0 || intr >= NHWI + NSWI)
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93 panic("register_int: bad intr %d", intr);
94
95 rec = malloc(sizeof(intrec_t), M_DEVBUF, M_NOWAIT);
96 if (rec == NULL)
97 panic("register_swi: malloc failed");
98 rec->handler = handler;
99 rec->argument = arg;
100 rec->name = name;
101 rec->intr = intr;
102 rec->next = NULL;
103
104 list = &intlists[intr];
105
106 /*
107 * Create an interrupt thread if necessary, leave it in an unscheduled
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108 * state. The kthread restore function exits a critical section before
109 * starting the function so we need *TWO* critical sections in order
110 * for the handler to begin running in one.
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111 */
112 if ((td = ithreads[intr]) == NULL) {
113 lwkt_create((void *)ithread_handler, (void *)intr, &ithreads[intr],
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114 &ithread_ary[intr], TDF_STOPREQ|TDF_INTTHREAD, -1,
115 "ithread %d", intr);
ef0fdad1 116 td = ithreads[intr];
4b5f931b 117 if (intr >= NHWI && intr < NHWI + NSWI)
26a0694b 118 lwkt_setpri(td, TDPRI_SOFT_NORM + TDPRI_CRIT * 2);
4b5f931b 119 else
26a0694b 120 lwkt_setpri(td, TDPRI_INT_MED + TDPRI_CRIT * 2);
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121 }
122
123 /*
124 * Add the record to the interrupt list
125 */
126 crit_enter(); /* token */
127 while (*list != NULL)
128 list = &(*list)->next;
129 *list = rec;
130 crit_exit();
96728c05 131 return(td);
ef0fdad1 132}
984263bc 133
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134void
135unregister_swi(int intr, inthand2_t *handler)
136{
137 if (intr < NHWI || intr >= NHWI + NSWI)
138 panic("register_swi: bad intr %d", intr);
139 unregister_int(intr, handler);
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140}
141
142void
ef0fdad1 143unregister_int(int intr, inthand2_t handler)
984263bc 144{
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145 intrec_t **list;
146 intrec_t *rec;
147
148 if (intr < 0 || intr > NHWI + NSWI)
149 panic("register_int: bad intr %d", intr);
150 list = &intlists[intr];
151 crit_enter();
152 while ((rec = *list) != NULL) {
153 if (rec->handler == (void *)handler) {
154 *list = rec->next;
155 break;
984263bc 156 }
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157 list = &rec->next;
158 }
159 crit_exit();
160 if (rec != NULL) {
161 free(rec, M_DEVBUF);
162 } else {
163 printf("warning: unregister_int: int %d handler %p not found\n",
164 intr, handler);
165 }
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166}
167
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168void
169swi_setpriority(int intr, int pri)
170{
171 struct thread *td;
172
173 if (intr < NHWI || intr >= NHWI + NSWI)
174 panic("register_swi: bad intr %d", intr);
175 if ((td = ithreads[intr]) != NULL)
176 lwkt_setpri(td, pri);
177}
178
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179void
180register_randintr(int intr)
181{
182 struct random_softc *sc = &irandom_ary[intr];
183 sc->sc_intr = intr;
184 sc->sc_enabled = 1;
185}
186
187void
188unregister_randintr(int intr)
189{
190 struct random_softc *sc = &irandom_ary[intr];
191 sc->sc_enabled = 0;
192}
193
ef0fdad1 194/*
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195 * Dispatch an interrupt. If there's nothing to do we have a stray
196 * interrupt and can just return, leaving the interrupt masked.
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197 *
198 * We need to schedule the interrupt and set its irunning[] bit. If
199 * we are not on the interrupt thread's cpu we have to send a message
200 * to the correct cpu that will issue the desired action (interlocking
201 * with the interrupt thread's critical section).
202 *
203 * We are NOT in a critical section, which will allow the scheduled
71ef2f5c 204 * interrupt to preempt us. The MP lock might *NOT* be held here.
ef0fdad1 205 */
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206static void
207sched_ithd_remote(void *arg)
208{
209 sched_ithd((int)arg);
210}
211
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212void
213sched_ithd(int intr)
214{
215 thread_t td;
216
217 if ((td = ithreads[intr]) != NULL) {
b68b7282 218 if (intlists[intr] == NULL) {
ef0fdad1 219 printf("sched_ithd: stray interrupt %d\n", intr);
b68b7282 220 } else {
a72187e9 221 if (td->td_gd == mycpu) {
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222 irunning[intr] = 1;
223 lwkt_schedule(td); /* preemption handled internally */
224 } else {
2db3b277 225 lwkt_send_ipiq(td->td_gd, sched_ithd_remote, (void *)intr);
96728c05 226 }
b68b7282 227 }
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228 } else {
229 printf("sched_ithd: stray interrupt %d\n", intr);
230 }
231}
232
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233/*
234 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL
235 * might not be held).
236 */
237static void
93781523 238ithread_livelock_wakeup(systimer_t info)
37d44089 239{
93781523 240 int intr = (int)info->data;
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241 thread_t td;
242
243 if ((td = ithreads[intr]) != NULL)
244 lwkt_schedule(td);
245}
246
247
b68b7282 248/*
26a0694b 249 * Interrupt threads run this as their main loop. The handler should be
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250 * in a critical section on entry and the BGL is usually left held (for now).
251 *
252 * The irunning state starts at 0. When an interrupt occurs, the hardware
253 * interrupt is disabled and sched_ithd() The HW interrupt remains disabled
254 * until all routines have run. We then call ithread_done() to reenable
255 * the HW interrupt and deschedule us until the next interrupt.
b68b7282 256 */
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257
258#define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */
259
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260static void
261ithread_handler(void *arg)
262{
263 int intr = (int)arg;
37d44089 264 int freq;
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265 u_int bticks;
266 u_int cputicks;
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267 intrec_t **list = &intlists[intr];
268 intrec_t *rec;
269 intrec_t *nrec;
7e071e7a 270 struct random_softc *sc = &irandom_ary[intr];
ef0fdad1 271
26a0694b 272 KKASSERT(curthread->td_pri >= TDPRI_CRIT);
ef0fdad1 273 for (;;) {
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274 /*
275 * We can get woken up by the livelock periodic code too, run the
276 * handlers only if there is a real interrupt pending. Clear
277 * irunning[] prior to running the handlers to interlock new
278 * events.
279 */
280 if (irunning[intr]) {
281 irunning[intr] = 0;
282 for (rec = *list; rec; rec = nrec) {
283 nrec = rec->next;
284 rec->handler(rec->argument);
285 }
ef0fdad1 286 }
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287
288 /*
289 * This is our interrupt hook to add rate randomness to the random
290 * number generator.
291 */
7e071e7a 292 if (sc->sc_enabled)
96728c05 293 add_interrupt_randomness(intr);
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294
295 /*
296 * This is our livelock test. If we hit the rate limit we
297 * limit ourselves to 10000 interrupts/sec until the rate
298 * falls below 50% of that value, then we unlimit again.
299 */
93781523 300 cputicks = cputimer_count();
37d44089 301 ++ill_count[intr];
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302 bticks = cputicks - ill_ticks[intr];
303 ill_ticks[intr] = cputicks;
304 if (bticks > cputimer_freq)
305 bticks = cputimer_freq;
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306
307 switch(ill_state[intr]) {
308 case LIVELOCK_NONE:
309 ill_delta[intr] += bticks;
93781523 310 if (ill_delta[intr] < LIVELOCK_TIMEFRAME(cputimer_freq))
37d44089 311 break;
93781523 312 freq = (int64_t)ill_count[intr] * cputimer_freq / ill_delta[intr];
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313 ill_delta[intr] = 0;
314 ill_count[intr] = 0;
315 if (freq < livelock_limit)
316 break;
317 printf("intr %d at %d hz, livelocked! limiting at %d hz\n",
318 intr, freq, livelock_fallback);
319 ill_state[intr] = LIVELOCK_LIMITED;
320 bticks = 0;
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321 /* force periodic check to avoid stale removal (if ints stop) */
322 systimer_init_periodic(&ill_rtimer[intr], ithread_livelock_wakeup,
323 (void *)intr, 1);
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324 /* fall through */
325 case LIVELOCK_LIMITED:
326 /*
327 * Delay (us) before rearming the interrupt
328 */
329 systimer_init_oneshot(&ill_timer[intr], ithread_livelock_wakeup,
330 (void *)intr, 1 + 1000000 / livelock_fallback);
331 lwkt_deschedule_self(curthread);
332 lwkt_switch();
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333
334 /* in case we were woken up by something else */
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335 systimer_del(&ill_timer[intr]);
336
337 /*
338 * Calculate interrupt rate (note that due to our delay it
339 * will not exceed livelock_fallback).
340 */
341 ill_delta[intr] += bticks;
93781523 342 if (ill_delta[intr] < LIVELOCK_TIMEFRAME(cputimer_freq))
37d44089 343 break;
93781523 344 freq = (int64_t)ill_count[intr] * cputimer_freq / ill_delta[intr];
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345 ill_delta[intr] = 0;
346 ill_count[intr] = 0;
347 if (freq < (livelock_fallback >> 1)) {
348 printf("intr %d at %d hz, removing livelock limit\n",
349 intr, freq);
350 ill_state[intr] = LIVELOCK_NONE;
93781523 351 systimer_del(&ill_rtimer[intr]);
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352 }
353 break;
354 }
355
356 /*
357 * If another interrupt has not been queued we can reenable the
358 * hardware interrupt and go to sleep.
359 */
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360 if (irunning[intr] == 0)
361 ithread_done(intr);
ef0fdad1 362 }
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363}
364
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365/*
366 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt.
367 * The data for this machine dependent, and the declarations are in machine
368 * dependent code. The layout of intrnames and intrcnt however is machine
369 * independent.
370 *
371 * We do not know the length of intrcnt and intrnames at compile time, so
372 * calculate things at run time.
373 */
374static int
375sysctl_intrnames(SYSCTL_HANDLER_ARGS)
376{
377 return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames,
378 req));
379}
380
381SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD,
382 NULL, 0, sysctl_intrnames, "", "Interrupt Names");
383
384static int
385sysctl_intrcnt(SYSCTL_HANDLER_ARGS)
386{
387 return (sysctl_handle_opaque(oidp, intrcnt,
388 (char *)eintrcnt - (char *)intrcnt, req));
389}
390
391SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD,
392 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts");