Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_intr.c
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1 /*- 2 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> 3 * 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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD: releng/6.1/sys/kern/kern_intr.c 157786 2006-04-15 20:08:33Z scottl $"); 29 30 #include "opt_ddb.h" 31 32 #include <sys/param.h> 33 #include <sys/bus.h> 34 #include <sys/conf.h> 35 #include <sys/rtprio.h> 36 #include <sys/systm.h> 37 #include <sys/interrupt.h> 38 #include <sys/kernel.h> 39 #include <sys/kthread.h> 40 #include <sys/ktr.h> 41 #include <sys/limits.h> 42 #include <sys/lock.h> 43 #include <sys/malloc.h> 44 #include <sys/mutex.h> 45 #include <sys/proc.h> 46 #include <sys/random.h> 47 #include <sys/resourcevar.h> 48 #include <sys/sched.h> 49 #include <sys/sysctl.h> 50 #include <sys/unistd.h> 51 #include <sys/vmmeter.h> 52 #include <machine/atomic.h> 53 #include <machine/cpu.h> 54 #include <machine/md_var.h> 55 #include <machine/stdarg.h> 56 #ifdef DDB 57 #include <ddb/ddb.h> 58 #include <ddb/db_sym.h> 59 #endif 60 61 /* 62 * Describe an interrupt thread. There is one of these per interrupt event. 63 */ 64 struct intr_thread { 65 struct intr_event *it_event; 66 struct thread *it_thread; /* Kernel thread. */ 67 int it_flags; /* (j) IT_* flags. */ 68 int it_need; /* Needs service. */ 69 }; 70 71 /* Interrupt thread flags kept in it_flags */ 72 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */ 73 74 struct intr_entropy { 75 struct thread *td; 76 uintptr_t event; 77 }; 78 79 struct intr_event *clk_intr_event; 80 struct intr_event *tty_intr_event; 81 void *softclock_ih; 82 void *vm_ih; 83 84 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads"); 85 86 static int intr_storm_threshold = 500; 87 TUNABLE_INT("hw.intr_storm_threshold", &intr_storm_threshold); 88 SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RW, 89 &intr_storm_threshold, 0, 90 "Number of consecutive interrupts before storm protection is enabled"); 91 static TAILQ_HEAD(, intr_event) event_list = 92 TAILQ_HEAD_INITIALIZER(event_list); 93 94 static void intr_event_update(struct intr_event *ie); 95 static struct intr_thread *ithread_create(const char *name); 96 static void ithread_destroy2(struct intr_thread *ithread); 97 static void ithread_execute_handlers(struct proc *p, struct intr_event *ie); 98 static void ithread_loop(void *); 99 static void ithread_update(struct intr_thread *ithd); 100 static void start_softintr(void *); 101 102 u_char 103 intr_priority(enum intr_type flags) 104 { 105 u_char pri; 106 107 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET | 108 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV); 109 switch (flags) { 110 case INTR_TYPE_TTY: 111 pri = PI_TTYLOW; 112 break; 113 case INTR_TYPE_BIO: 114 /* 115 * XXX We need to refine this. BSD/OS distinguishes 116 * between tape and disk priorities. 117 */ 118 pri = PI_DISK; 119 break; 120 case INTR_TYPE_NET: 121 pri = PI_NET; 122 break; 123 case INTR_TYPE_CAM: 124 pri = PI_DISK; /* XXX or PI_CAM? */ 125 break; 126 case INTR_TYPE_AV: /* Audio/video */ 127 pri = PI_AV; 128 break; 129 case INTR_TYPE_CLK: 130 pri = PI_REALTIME; 131 break; 132 case INTR_TYPE_MISC: 133 pri = PI_DULL; /* don't care */ 134 break; 135 default: 136 /* We didn't specify an interrupt level. */ 137 panic("intr_priority: no interrupt type in flags"); 138 } 139 140 return pri; 141 } 142 143 /* 144 * Update an ithread based on the associated intr_event. 145 */ 146 static void 147 ithread_update(struct intr_thread *ithd) 148 { 149 struct intr_event *ie; 150 struct thread *td; 151 u_char pri; 152 153 ie = ithd->it_event; 154 td = ithd->it_thread; 155 156 /* Determine the overall priority of this event. */ 157 if (TAILQ_EMPTY(&ie->ie_handlers)) 158 pri = PRI_MAX_ITHD; 159 else 160 pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri; 161 162 /* Update name and priority. */ 163 strlcpy(td->td_proc->p_comm, ie->ie_fullname, 164 sizeof(td->td_proc->p_comm)); 165 mtx_lock_spin(&sched_lock); 166 sched_prio(td, pri); 167 mtx_unlock_spin(&sched_lock); 168 } 169 170 /* 171 * Regenerate the full name of an interrupt event and update its priority. 172 */ 173 static void 174 intr_event_update(struct intr_event *ie) 175 { 176 struct intr_handler *ih; 177 char *last; 178 int missed, space; 179 180 /* Start off with no entropy and just the name of the event. */ 181 mtx_assert(&ie->ie_lock, MA_OWNED); 182 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname)); 183 ie->ie_flags &= ~IE_ENTROPY; 184 missed = 0; 185 space = 1; 186 187 /* Run through all the handlers updating values. */ 188 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 189 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 < 190 sizeof(ie->ie_fullname)) { 191 strcat(ie->ie_fullname, " "); 192 strcat(ie->ie_fullname, ih->ih_name); 193 space = 0; 194 } else 195 missed++; 196 if (ih->ih_flags & IH_ENTROPY) 197 ie->ie_flags |= IE_ENTROPY; 198 } 199 200 /* 201 * If the handler names were too long, add +'s to indicate missing 202 * names. If we run out of room and still have +'s to add, change 203 * the last character from a + to a *. 204 */ 205 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2]; 206 while (missed-- > 0) { 207 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) { 208 if (*last == '+') { 209 *last = '*'; 210 break; 211 } else 212 *last = '+'; 213 } else if (space) { 214 strcat(ie->ie_fullname, " +"); 215 space = 0; 216 } else 217 strcat(ie->ie_fullname, "+"); 218 } 219 220 /* 221 * If this event has an ithread, update it's priority and 222 * name. 223 */ 224 if (ie->ie_thread != NULL) 225 ithread_update(ie->ie_thread); 226 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname); 227 } 228 229 int 230 intr_event_create(struct intr_event **event, void *source, int flags, 231 void (*enable)(void *), const char *fmt, ...) 232 { 233 struct intr_event *ie; 234 va_list ap; 235 236 /* The only valid flag during creation is IE_SOFT. */ 237 if ((flags & ~IE_SOFT) != 0) 238 return (EINVAL); 239 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO); 240 ie->ie_source = source; 241 ie->ie_enable = enable; 242 ie->ie_flags = flags; 243 TAILQ_INIT(&ie->ie_handlers); 244 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF); 245 246 va_start(ap, fmt); 247 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap); 248 va_end(ap); 249 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname)); 250 mtx_pool_lock(mtxpool_sleep, &event_list); 251 TAILQ_INSERT_TAIL(&event_list, ie, ie_list); 252 mtx_pool_unlock(mtxpool_sleep, &event_list); 253 if (event != NULL) 254 *event = ie; 255 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name); 256 return (0); 257 } 258 259 int 260 intr_event_destroy(struct intr_event *ie) 261 { 262 263 mtx_lock(&ie->ie_lock); 264 if (!TAILQ_EMPTY(&ie->ie_handlers)) { 265 mtx_unlock(&ie->ie_lock); 266 return (EBUSY); 267 } 268 mtx_pool_lock(mtxpool_sleep, &event_list); 269 TAILQ_REMOVE(&event_list, ie, ie_list); 270 mtx_pool_unlock(mtxpool_sleep, &event_list); 271 #ifndef notyet 272 if (ie->ie_thread != NULL) { 273 ithread_destroy2(ie->ie_thread); 274 ie->ie_thread = NULL; 275 } 276 #endif 277 mtx_unlock(&ie->ie_lock); 278 mtx_destroy(&ie->ie_lock); 279 free(ie, M_ITHREAD); 280 return (0); 281 } 282 283 static struct intr_thread * 284 ithread_create(const char *name) 285 { 286 struct intr_thread *ithd; 287 struct thread *td; 288 struct proc *p; 289 int error; 290 291 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO); 292 293 error = kthread_create(ithread_loop, ithd, &p, RFSTOPPED | RFHIGHPID, 294 0, "%s", name); 295 if (error) 296 panic("kthread_create() failed with %d", error); 297 td = FIRST_THREAD_IN_PROC(p); /* XXXKSE */ 298 mtx_lock_spin(&sched_lock); 299 td->td_ksegrp->kg_pri_class = PRI_ITHD; 300 TD_SET_IWAIT(td); 301 mtx_unlock_spin(&sched_lock); 302 td->td_pflags |= TDP_ITHREAD; 303 ithd->it_thread = td; 304 CTR2(KTR_INTR, "%s: created %s", __func__, name); 305 return (ithd); 306 } 307 308 static void 309 ithread_destroy2(struct intr_thread *ithread) 310 { 311 struct thread *td; 312 313 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name); 314 td = ithread->it_thread; 315 mtx_lock_spin(&sched_lock); 316 ithread->it_flags |= IT_DEAD; 317 if (TD_AWAITING_INTR(td)) { 318 TD_CLR_IWAIT(td); 319 setrunqueue(td, SRQ_INTR); 320 } 321 mtx_unlock_spin(&sched_lock); 322 } 323 324 int 325 intr_event_add_handler(struct intr_event *ie, const char *name, 326 driver_intr_t handler, void *arg, u_char pri, enum intr_type flags, 327 void **cookiep) 328 { 329 struct intr_handler *ih, *temp_ih; 330 struct intr_thread *it; 331 332 if (ie == NULL || name == NULL || handler == NULL) 333 return (EINVAL); 334 335 /* Allocate and populate an interrupt handler structure. */ 336 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO); 337 ih->ih_handler = handler; 338 ih->ih_argument = arg; 339 ih->ih_name = name; 340 ih->ih_event = ie; 341 ih->ih_pri = pri; 342 if (flags & INTR_FAST) 343 ih->ih_flags = IH_FAST; 344 else if (flags & INTR_EXCL) 345 ih->ih_flags = IH_EXCLUSIVE; 346 if (flags & INTR_MPSAFE) 347 ih->ih_flags |= IH_MPSAFE; 348 if (flags & INTR_ENTROPY) 349 ih->ih_flags |= IH_ENTROPY; 350 351 /* We can only have one exclusive handler in a event. */ 352 mtx_lock(&ie->ie_lock); 353 if (!TAILQ_EMPTY(&ie->ie_handlers)) { 354 if ((flags & INTR_EXCL) || 355 (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) { 356 mtx_unlock(&ie->ie_lock); 357 free(ih, M_ITHREAD); 358 return (EINVAL); 359 } 360 } 361 362 /* Add the new handler to the event in priority order. */ 363 TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { 364 if (temp_ih->ih_pri > ih->ih_pri) 365 break; 366 } 367 if (temp_ih == NULL) 368 TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); 369 else 370 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); 371 intr_event_update(ie); 372 373 /* Create a thread if we need one. */ 374 while (ie->ie_thread == NULL && !(flags & INTR_FAST)) { 375 if (ie->ie_flags & IE_ADDING_THREAD) 376 msleep(ie, &ie->ie_lock, curthread->td_priority, 377 "ithread", 0); 378 else { 379 ie->ie_flags |= IE_ADDING_THREAD; 380 mtx_unlock(&ie->ie_lock); 381 it = ithread_create("intr: newborn"); 382 mtx_lock(&ie->ie_lock); 383 ie->ie_flags &= ~IE_ADDING_THREAD; 384 ie->ie_thread = it; 385 it->it_event = ie; 386 ithread_update(it); 387 wakeup(ie); 388 } 389 } 390 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, 391 ie->ie_name); 392 mtx_unlock(&ie->ie_lock); 393 394 if (cookiep != NULL) 395 *cookiep = ih; 396 return (0); 397 } 398 399 int 400 intr_event_remove_handler(void *cookie) 401 { 402 struct intr_handler *handler = (struct intr_handler *)cookie; 403 struct intr_event *ie; 404 #ifdef INVARIANTS 405 struct intr_handler *ih; 406 #endif 407 #ifdef notyet 408 int dead; 409 #endif 410 411 if (handler == NULL) 412 return (EINVAL); 413 ie = handler->ih_event; 414 KASSERT(ie != NULL, 415 ("interrupt handler \"%s\" has a NULL interrupt event", 416 handler->ih_name)); 417 mtx_lock(&ie->ie_lock); 418 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name, 419 ie->ie_name); 420 #ifdef INVARIANTS 421 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 422 if (ih == handler) 423 goto ok; 424 mtx_unlock(&ie->ie_lock); 425 panic("interrupt handler \"%s\" not found in interrupt event \"%s\"", 426 ih->ih_name, ie->ie_name); 427 ok: 428 #endif 429 /* 430 * If there is no ithread, then just remove the handler and return. 431 * XXX: Note that an INTR_FAST handler might be running on another 432 * CPU! 433 */ 434 if (ie->ie_thread == NULL) { 435 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 436 mtx_unlock(&ie->ie_lock); 437 free(handler, M_ITHREAD); 438 return (0); 439 } 440 441 /* 442 * If the interrupt thread is already running, then just mark this 443 * handler as being dead and let the ithread do the actual removal. 444 * 445 * During a cold boot while cold is set, msleep() does not sleep, 446 * so we have to remove the handler here rather than letting the 447 * thread do it. 448 */ 449 mtx_lock_spin(&sched_lock); 450 if (!TD_AWAITING_INTR(ie->ie_thread->it_thread) && !cold) { 451 handler->ih_flags |= IH_DEAD; 452 453 /* 454 * Ensure that the thread will process the handler list 455 * again and remove this handler if it has already passed 456 * it on the list. 457 */ 458 ie->ie_thread->it_need = 1; 459 } else 460 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 461 mtx_unlock_spin(&sched_lock); 462 while (handler->ih_flags & IH_DEAD) 463 msleep(handler, &ie->ie_lock, curthread->td_priority, "iev_rmh", 464 0); 465 intr_event_update(ie); 466 #ifdef notyet 467 /* 468 * XXX: This could be bad in the case of ppbus(8). Also, I think 469 * this could lead to races of stale data when servicing an 470 * interrupt. 471 */ 472 dead = 1; 473 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 474 if (!(ih->ih_flags & IH_FAST)) { 475 dead = 0; 476 break; 477 } 478 } 479 if (dead) { 480 ithread_destroy2(ie->ie_thread); 481 ie->ie_thread = NULL; 482 } 483 #endif 484 mtx_unlock(&ie->ie_lock); 485 free(handler, M_ITHREAD); 486 return (0); 487 } 488 489 int 490 intr_event_schedule_thread(struct intr_event *ie) 491 { 492 struct intr_entropy entropy; 493 struct intr_thread *it; 494 struct thread *td; 495 struct thread *ctd; 496 struct proc *p; 497 498 /* 499 * If no ithread or no handlers, then we have a stray interrupt. 500 */ 501 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) || 502 ie->ie_thread == NULL) 503 return (EINVAL); 504 505 ctd = curthread; 506 it = ie->ie_thread; 507 td = it->it_thread; 508 p = td->td_proc; 509 510 /* 511 * If any of the handlers for this ithread claim to be good 512 * sources of entropy, then gather some. 513 */ 514 if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) { 515 CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__, 516 p->p_pid, p->p_comm); 517 entropy.event = (uintptr_t)ie; 518 entropy.td = ctd; 519 random_harvest(&entropy, sizeof(entropy), 2, 0, 520 RANDOM_INTERRUPT); 521 } 522 523 KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name)); 524 525 /* 526 * Set it_need to tell the thread to keep running if it is already 527 * running. Then, grab sched_lock and see if we actually need to 528 * put this thread on the runqueue. 529 */ 530 it->it_need = 1; 531 mtx_lock_spin(&sched_lock); 532 if (TD_AWAITING_INTR(td)) { 533 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid, 534 p->p_comm); 535 TD_CLR_IWAIT(td); 536 setrunqueue(td, SRQ_INTR); 537 } else { 538 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d", 539 __func__, p->p_pid, p->p_comm, it->it_need, td->td_state); 540 } 541 mtx_unlock_spin(&sched_lock); 542 543 return (0); 544 } 545 546 /* 547 * Add a software interrupt handler to a specified event. If a given event 548 * is not specified, then a new event is created. 549 */ 550 int 551 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler, 552 void *arg, int pri, enum intr_type flags, void **cookiep) 553 { 554 struct intr_event *ie; 555 int error; 556 557 if (flags & (INTR_FAST | INTR_ENTROPY)) 558 return (EINVAL); 559 560 ie = (eventp != NULL) ? *eventp : NULL; 561 562 if (ie != NULL) { 563 if (!(ie->ie_flags & IE_SOFT)) 564 return (EINVAL); 565 } else { 566 error = intr_event_create(&ie, NULL, IE_SOFT, NULL, 567 "swi%d:", pri); 568 if (error) 569 return (error); 570 if (eventp != NULL) 571 *eventp = ie; 572 } 573 return (intr_event_add_handler(ie, name, handler, arg, 574 (pri * RQ_PPQ) + PI_SOFT, flags, cookiep)); 575 /* XXKSE.. think of a better way to get separate queues */ 576 } 577 578 /* 579 * Schedule a software interrupt thread. 580 */ 581 void 582 swi_sched(void *cookie, int flags) 583 { 584 struct intr_handler *ih = (struct intr_handler *)cookie; 585 struct intr_event *ie = ih->ih_event; 586 int error; 587 588 PCPU_LAZY_INC(cnt.v_intr); 589 590 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name, 591 ih->ih_need); 592 593 /* 594 * Set ih_need for this handler so that if the ithread is already 595 * running it will execute this handler on the next pass. Otherwise, 596 * it will execute it the next time it runs. 597 */ 598 atomic_store_rel_int(&ih->ih_need, 1); 599 if (!(flags & SWI_DELAY)) { 600 error = intr_event_schedule_thread(ie); 601 KASSERT(error == 0, ("stray software interrupt")); 602 } 603 } 604 605 /* 606 * Remove a software interrupt handler. Currently this code does not 607 * remove the associated interrupt event if it becomes empty. Calling code 608 * may do so manually via intr_event_destroy(), but that's not really 609 * an optimal interface. 610 */ 611 int 612 swi_remove(void *cookie) 613 { 614 615 return (intr_event_remove_handler(cookie)); 616 } 617 618 /* ABI compatibility shims. */ 619 #undef ithread_remove_handler 620 #undef ithread_destroy 621 int ithread_remove_handler(void *); 622 int ithread_destroy(struct ithd *); 623 624 int 625 ithread_remove_handler(void *cookie) 626 { 627 628 return (intr_event_remove_handler(cookie)); 629 } 630 631 int 632 ithread_destroy(struct ithd *ithread) 633 { 634 635 return (intr_event_destroy(ithread)); 636 } 637 638 static void 639 ithread_execute_handlers(struct proc *p, struct intr_event *ie) 640 { 641 struct intr_handler *ih, *ihn; 642 643 /* Interrupt handlers should not sleep. */ 644 if (!(ie->ie_flags & IE_SOFT)) 645 THREAD_NO_SLEEPING(); 646 TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) { 647 648 /* 649 * If this handler is marked for death, remove it from 650 * the list of handlers and wake up the sleeper. 651 */ 652 if (ih->ih_flags & IH_DEAD) { 653 mtx_lock(&ie->ie_lock); 654 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next); 655 ih->ih_flags &= ~IH_DEAD; 656 wakeup(ih); 657 mtx_unlock(&ie->ie_lock); 658 continue; 659 } 660 661 /* 662 * For software interrupt threads, we only execute 663 * handlers that have their need flag set. Hardware 664 * interrupt threads always invoke all of their handlers. 665 */ 666 if (ie->ie_flags & IE_SOFT) { 667 if (!ih->ih_need) 668 continue; 669 else 670 atomic_store_rel_int(&ih->ih_need, 0); 671 } 672 673 /* Fast handlers are handled in primary interrupt context. */ 674 if (ih->ih_flags & IH_FAST) 675 continue; 676 677 /* Execute this handler. */ 678 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x", 679 __func__, p->p_pid, (void *)ih->ih_handler, ih->ih_argument, 680 ih->ih_name, ih->ih_flags); 681 682 if (!(ih->ih_flags & IH_MPSAFE)) 683 mtx_lock(&Giant); 684 ih->ih_handler(ih->ih_argument); 685 if (!(ih->ih_flags & IH_MPSAFE)) 686 mtx_unlock(&Giant); 687 } 688 if (!(ie->ie_flags & IE_SOFT)) 689 THREAD_SLEEPING_OK(); 690 691 /* 692 * Interrupt storm handling: 693 * 694 * If this interrupt source is currently storming, then throttle 695 * it to only fire the handler once per clock tick. 696 * 697 * If this interrupt source is not currently storming, but the 698 * number of back to back interrupts exceeds the storm threshold, 699 * then enter storming mode. 700 */ 701 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold) { 702 if (ie->ie_warned == 0) { 703 printf( 704 "Interrupt storm detected on \"%s\"; throttling interrupt source\n", 705 ie->ie_name); 706 ie->ie_warned = 1; 707 } 708 tsleep(&ie->ie_count, curthread->td_priority, "istorm", 1); 709 } else 710 ie->ie_count++; 711 712 /* 713 * Now that all the handlers have had a chance to run, reenable 714 * the interrupt source. 715 */ 716 if (ie->ie_enable != NULL) 717 ie->ie_enable(ie->ie_source); 718 } 719 720 /* 721 * This is the main code for interrupt threads. 722 */ 723 static void 724 ithread_loop(void *arg) 725 { 726 struct intr_thread *ithd; 727 struct intr_event *ie; 728 struct thread *td; 729 struct proc *p; 730 731 td = curthread; 732 p = td->td_proc; 733 ithd = (struct intr_thread *)arg; 734 KASSERT(ithd->it_thread == td, 735 ("%s: ithread and proc linkage out of sync", __func__)); 736 ie = ithd->it_event; 737 ie->ie_count = 0; 738 739 /* 740 * As long as we have interrupts outstanding, go through the 741 * list of handlers, giving each one a go at it. 742 */ 743 for (;;) { 744 /* 745 * If we are an orphaned thread, then just die. 746 */ 747 if (ithd->it_flags & IT_DEAD) { 748 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__, 749 p->p_pid, p->p_comm); 750 free(ithd, M_ITHREAD); 751 kthread_exit(0); 752 } 753 754 /* 755 * Service interrupts. If another interrupt arrives while 756 * we are running, it will set it_need to note that we 757 * should make another pass. 758 */ 759 while (ithd->it_need) { 760 /* 761 * This might need a full read and write barrier 762 * to make sure that this write posts before any 763 * of the memory or device accesses in the 764 * handlers. 765 */ 766 atomic_store_rel_int(&ithd->it_need, 0); 767 ithread_execute_handlers(p, ie); 768 } 769 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); 770 mtx_assert(&Giant, MA_NOTOWNED); 771 772 /* 773 * Processed all our interrupts. Now get the sched 774 * lock. This may take a while and it_need may get 775 * set again, so we have to check it again. 776 */ 777 mtx_lock_spin(&sched_lock); 778 if (!ithd->it_need && !(ithd->it_flags & IT_DEAD)) { 779 TD_SET_IWAIT(td); 780 ie->ie_count = 0; 781 mi_switch(SW_VOL, NULL); 782 } 783 mtx_unlock_spin(&sched_lock); 784 } 785 } 786 787 #ifdef DDB 788 /* 789 * Dump details about an interrupt handler 790 */ 791 static void 792 db_dump_intrhand(struct intr_handler *ih) 793 { 794 int comma; 795 796 db_printf("\t%-10s ", ih->ih_name); 797 switch (ih->ih_pri) { 798 case PI_REALTIME: 799 db_printf("CLK "); 800 break; 801 case PI_AV: 802 db_printf("AV "); 803 break; 804 case PI_TTYHIGH: 805 case PI_TTYLOW: 806 db_printf("TTY "); 807 break; 808 case PI_TAPE: 809 db_printf("TAPE"); 810 break; 811 case PI_NET: 812 db_printf("NET "); 813 break; 814 case PI_DISK: 815 case PI_DISKLOW: 816 db_printf("DISK"); 817 break; 818 case PI_DULL: 819 db_printf("DULL"); 820 break; 821 default: 822 if (ih->ih_pri >= PI_SOFT) 823 db_printf("SWI "); 824 else 825 db_printf("%4u", ih->ih_pri); 826 break; 827 } 828 db_printf(" "); 829 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC); 830 db_printf("(%p)", ih->ih_argument); 831 if (ih->ih_need || 832 (ih->ih_flags & (IH_FAST | IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD | 833 IH_MPSAFE)) != 0) { 834 db_printf(" {"); 835 comma = 0; 836 if (ih->ih_flags & IH_FAST) { 837 db_printf("FAST"); 838 comma = 1; 839 } 840 if (ih->ih_flags & IH_EXCLUSIVE) { 841 if (comma) 842 db_printf(", "); 843 db_printf("EXCL"); 844 comma = 1; 845 } 846 if (ih->ih_flags & IH_ENTROPY) { 847 if (comma) 848 db_printf(", "); 849 db_printf("ENTROPY"); 850 comma = 1; 851 } 852 if (ih->ih_flags & IH_DEAD) { 853 if (comma) 854 db_printf(", "); 855 db_printf("DEAD"); 856 comma = 1; 857 } 858 if (ih->ih_flags & IH_MPSAFE) { 859 if (comma) 860 db_printf(", "); 861 db_printf("MPSAFE"); 862 comma = 1; 863 } 864 if (ih->ih_need) { 865 if (comma) 866 db_printf(", "); 867 db_printf("NEED"); 868 } 869 db_printf("}"); 870 } 871 db_printf("\n"); 872 } 873 874 /* 875 * Dump details about a event. 876 */ 877 void 878 db_dump_intr_event(struct intr_event *ie, int handlers) 879 { 880 struct intr_handler *ih; 881 struct intr_thread *it; 882 int comma; 883 884 db_printf("%s ", ie->ie_fullname); 885 it = ie->ie_thread; 886 if (it != NULL) 887 db_printf("(pid %d)", it->it_thread->td_proc->p_pid); 888 else 889 db_printf("(no thread)"); 890 if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 || 891 (it != NULL && it->it_need)) { 892 db_printf(" {"); 893 comma = 0; 894 if (ie->ie_flags & IE_SOFT) { 895 db_printf("SOFT"); 896 comma = 1; 897 } 898 if (ie->ie_flags & IE_ENTROPY) { 899 if (comma) 900 db_printf(", "); 901 db_printf("ENTROPY"); 902 comma = 1; 903 } 904 if (ie->ie_flags & IE_ADDING_THREAD) { 905 if (comma) 906 db_printf(", "); 907 db_printf("ADDING_THREAD"); 908 comma = 1; 909 } 910 if (it != NULL && it->it_need) { 911 if (comma) 912 db_printf(", "); 913 db_printf("NEED"); 914 } 915 db_printf("}"); 916 } 917 db_printf("\n"); 918 919 if (handlers) 920 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 921 db_dump_intrhand(ih); 922 } 923 924 /* 925 * Dump data about interrupt handlers 926 */ 927 DB_SHOW_COMMAND(intr, db_show_intr) 928 { 929 struct intr_event *ie; 930 int quit, all, verbose; 931 932 quit = 0; 933 verbose = index(modif, 'v') != NULL; 934 all = index(modif, 'a') != NULL; 935 db_setup_paging(db_simple_pager, &quit, db_lines_per_page); 936 TAILQ_FOREACH(ie, &event_list, ie_list) { 937 if (!all && TAILQ_EMPTY(&ie->ie_handlers)) 938 continue; 939 db_dump_intr_event(ie, verbose); 940 } 941 } 942 #endif /* DDB */ 943 944 /* 945 * Start standard software interrupt threads 946 */ 947 static void 948 start_softintr(void *dummy) 949 { 950 struct proc *p; 951 952 if (swi_add(&clk_intr_event, "clock", softclock, NULL, SWI_CLOCK, 953 INTR_MPSAFE, &softclock_ih) || 954 swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih)) 955 panic("died while creating standard software ithreads"); 956 957 p = clk_intr_event->ie_thread->it_thread->td_proc; 958 PROC_LOCK(p); 959 p->p_flag |= P_NOLOAD; 960 PROC_UNLOCK(p); 961 } 962 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr, NULL) 963 964 /* 965 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 966 * The data for this machine dependent, and the declarations are in machine 967 * dependent code. The layout of intrnames and intrcnt however is machine 968 * independent. 969 * 970 * We do not know the length of intrcnt and intrnames at compile time, so 971 * calculate things at run time. 972 */ 973 static int 974 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 975 { 976 return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames, 977 req)); 978 } 979 980 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 981 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 982 983 static int 984 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 985 { 986 return (sysctl_handle_opaque(oidp, intrcnt, 987 (char *)eintrcnt - (char *)intrcnt, req)); 988 } 989 990 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 991 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 992 993 #ifdef DDB 994 /* 995 * DDB command to dump the interrupt statistics. 996 */ 997 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt) 998 { 999 u_long *i; 1000 char *cp; 1001 int quit; 1002 1003 cp = intrnames; 1004 db_setup_paging(db_simple_pager, &quit, db_lines_per_page); 1005 for (i = intrcnt, quit = 0; i != eintrcnt && !quit; i++) { 1006 if (*cp == '\0') 1007 break; 1008 if (*i != 0) 1009 db_printf("%s\t%lu\n", cp, *i); 1010 cp += strlen(cp) + 1; 1011 } 1012 } 1013 #endif
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