kern_intr.c revision 157784
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: head/sys/kern/kern_intr.c 157784 2006-04-15 18:54:56Z 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 */ 64struct 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 74struct intr_entropy { 75 struct thread *td; 76 uintptr_t event; 77}; 78 79struct intr_event *clk_intr_event; 80struct intr_event *tty_intr_event; 81void *softclock_ih; 82void *vm_ih; 83 84static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads"); 85 86static int intr_storm_threshold = 500; 87TUNABLE_INT("hw.intr_storm_threshold", &intr_storm_threshold); 88SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RW, 89 &intr_storm_threshold, 0, 90 "Number of consecutive interrupts before storm protection is enabled"); 91static TAILQ_HEAD(, intr_event) event_list = 92 TAILQ_HEAD_INITIALIZER(event_list); 93 94static void intr_event_update(struct intr_event *ie); 95static struct intr_thread *ithread_create(const char *name); 96static void ithread_destroy(struct intr_thread *ithread); 97static void ithread_execute_handlers(struct proc *p, struct intr_event *ie); 98static void ithread_loop(void *); 99static void ithread_update(struct intr_thread *ithd); 100static void start_softintr(void *); 101 102u_char 103intr_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 */ 146static void 147ithread_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 */ 173static void 174intr_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 229int 230intr_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 259int 260intr_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_destroy(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 283static struct intr_thread * 284ithread_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 308static void 309ithread_destroy(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 324int 325intr_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 399int 400intr_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); 427ok: 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_destroy(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 489int 490intr_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 */ 550int 551swi_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 */ 581void 582swi_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 */ 611int 612swi_remove(void *cookie) 613{ 614 615 return (intr_event_remove_handler(cookie)); 616} 617 618static void 619ithread_execute_handlers(struct proc *p, struct intr_event *ie) 620{ 621 struct intr_handler *ih, *ihn; 622 623 /* Interrupt handlers should not sleep. */ 624 if (!(ie->ie_flags & IE_SOFT)) 625 THREAD_NO_SLEEPING(); 626 TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) { 627 628 /* 629 * If this handler is marked for death, remove it from 630 * the list of handlers and wake up the sleeper. 631 */ 632 if (ih->ih_flags & IH_DEAD) { 633 mtx_lock(&ie->ie_lock); 634 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next); 635 ih->ih_flags &= ~IH_DEAD; 636 wakeup(ih); 637 mtx_unlock(&ie->ie_lock); 638 continue; 639 } 640 641 /* 642 * For software interrupt threads, we only execute 643 * handlers that have their need flag set. Hardware 644 * interrupt threads always invoke all of their handlers. 645 */ 646 if (ie->ie_flags & IE_SOFT) { 647 if (!ih->ih_need) 648 continue; 649 else 650 atomic_store_rel_int(&ih->ih_need, 0); 651 } 652 653 /* Fast handlers are handled in primary interrupt context. */ 654 if (ih->ih_flags & IH_FAST) 655 continue; 656 657 /* Execute this handler. */ 658 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x", 659 __func__, p->p_pid, (void *)ih->ih_handler, ih->ih_argument, 660 ih->ih_name, ih->ih_flags); 661 662 if (!(ih->ih_flags & IH_MPSAFE)) 663 mtx_lock(&Giant); 664 ih->ih_handler(ih->ih_argument); 665 if (!(ih->ih_flags & IH_MPSAFE)) 666 mtx_unlock(&Giant); 667 } 668 if (!(ie->ie_flags & IE_SOFT)) 669 THREAD_SLEEPING_OK(); 670 671 /* 672 * Interrupt storm handling: 673 * 674 * If this interrupt source is currently storming, then throttle 675 * it to only fire the handler once per clock tick. 676 * 677 * If this interrupt source is not currently storming, but the 678 * number of back to back interrupts exceeds the storm threshold, 679 * then enter storming mode. 680 */ 681 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold) { 682 if (ie->ie_warned == 0) { 683 printf( 684 "Interrupt storm detected on \"%s\"; throttling interrupt source\n", 685 ie->ie_name); 686 ie->ie_warned = 1; 687 } 688 tsleep(&ie->ie_count, curthread->td_priority, "istorm", 1); 689 } else 690 ie->ie_count++; 691 692 /* 693 * Now that all the handlers have had a chance to run, reenable 694 * the interrupt source. 695 */ 696 if (ie->ie_enable != NULL) 697 ie->ie_enable(ie->ie_source); 698} 699 700/* 701 * This is the main code for interrupt threads. 702 */ 703static void 704ithread_loop(void *arg) 705{ 706 struct intr_thread *ithd; 707 struct intr_event *ie; 708 struct thread *td; 709 struct proc *p; 710 711 td = curthread; 712 p = td->td_proc; 713 ithd = (struct intr_thread *)arg; 714 KASSERT(ithd->it_thread == td, 715 ("%s: ithread and proc linkage out of sync", __func__)); 716 ie = ithd->it_event; 717 ie->ie_count = 0; 718 719 /* 720 * As long as we have interrupts outstanding, go through the 721 * list of handlers, giving each one a go at it. 722 */ 723 for (;;) { 724 /* 725 * If we are an orphaned thread, then just die. 726 */ 727 if (ithd->it_flags & IT_DEAD) { 728 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__, 729 p->p_pid, p->p_comm); 730 free(ithd, M_ITHREAD); 731 kthread_exit(0); 732 } 733 734 /* 735 * Service interrupts. If another interrupt arrives while 736 * we are running, it will set it_need to note that we 737 * should make another pass. 738 */ 739 while (ithd->it_need) { 740 /* 741 * This might need a full read and write barrier 742 * to make sure that this write posts before any 743 * of the memory or device accesses in the 744 * handlers. 745 */ 746 atomic_store_rel_int(&ithd->it_need, 0); 747 ithread_execute_handlers(p, ie); 748 } 749 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); 750 mtx_assert(&Giant, MA_NOTOWNED); 751 752 /* 753 * Processed all our interrupts. Now get the sched 754 * lock. This may take a while and it_need may get 755 * set again, so we have to check it again. 756 */ 757 mtx_lock_spin(&sched_lock); 758 if (!ithd->it_need && !(ithd->it_flags & IT_DEAD)) { 759 TD_SET_IWAIT(td); 760 ie->ie_count = 0; 761 mi_switch(SW_VOL, NULL); 762 } 763 mtx_unlock_spin(&sched_lock); 764 } 765} 766 767#ifdef DDB 768/* 769 * Dump details about an interrupt handler 770 */ 771static void 772db_dump_intrhand(struct intr_handler *ih) 773{ 774 int comma; 775 776 db_printf("\t%-10s ", ih->ih_name); 777 switch (ih->ih_pri) { 778 case PI_REALTIME: 779 db_printf("CLK "); 780 break; 781 case PI_AV: 782 db_printf("AV "); 783 break; 784 case PI_TTYHIGH: 785 case PI_TTYLOW: 786 db_printf("TTY "); 787 break; 788 case PI_TAPE: 789 db_printf("TAPE"); 790 break; 791 case PI_NET: 792 db_printf("NET "); 793 break; 794 case PI_DISK: 795 case PI_DISKLOW: 796 db_printf("DISK"); 797 break; 798 case PI_DULL: 799 db_printf("DULL"); 800 break; 801 default: 802 if (ih->ih_pri >= PI_SOFT) 803 db_printf("SWI "); 804 else 805 db_printf("%4u", ih->ih_pri); 806 break; 807 } 808 db_printf(" "); 809 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC); 810 db_printf("(%p)", ih->ih_argument); 811 if (ih->ih_need || 812 (ih->ih_flags & (IH_FAST | IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD | 813 IH_MPSAFE)) != 0) { 814 db_printf(" {"); 815 comma = 0; 816 if (ih->ih_flags & IH_FAST) { 817 db_printf("FAST"); 818 comma = 1; 819 } 820 if (ih->ih_flags & IH_EXCLUSIVE) { 821 if (comma) 822 db_printf(", "); 823 db_printf("EXCL"); 824 comma = 1; 825 } 826 if (ih->ih_flags & IH_ENTROPY) { 827 if (comma) 828 db_printf(", "); 829 db_printf("ENTROPY"); 830 comma = 1; 831 } 832 if (ih->ih_flags & IH_DEAD) { 833 if (comma) 834 db_printf(", "); 835 db_printf("DEAD"); 836 comma = 1; 837 } 838 if (ih->ih_flags & IH_MPSAFE) { 839 if (comma) 840 db_printf(", "); 841 db_printf("MPSAFE"); 842 comma = 1; 843 } 844 if (ih->ih_need) { 845 if (comma) 846 db_printf(", "); 847 db_printf("NEED"); 848 } 849 db_printf("}"); 850 } 851 db_printf("\n"); 852} 853 854/* 855 * Dump details about a event. 856 */ 857void 858db_dump_intr_event(struct intr_event *ie, int handlers) 859{ 860 struct intr_handler *ih; 861 struct intr_thread *it; 862 int comma; 863 864 db_printf("%s ", ie->ie_fullname); 865 it = ie->ie_thread; 866 if (it != NULL) 867 db_printf("(pid %d)", it->it_thread->td_proc->p_pid); 868 else 869 db_printf("(no thread)"); 870 if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 || 871 (it != NULL && it->it_need)) { 872 db_printf(" {"); 873 comma = 0; 874 if (ie->ie_flags & IE_SOFT) { 875 db_printf("SOFT"); 876 comma = 1; 877 } 878 if (ie->ie_flags & IE_ENTROPY) { 879 if (comma) 880 db_printf(", "); 881 db_printf("ENTROPY"); 882 comma = 1; 883 } 884 if (ie->ie_flags & IE_ADDING_THREAD) { 885 if (comma) 886 db_printf(", "); 887 db_printf("ADDING_THREAD"); 888 comma = 1; 889 } 890 if (it != NULL && it->it_need) { 891 if (comma) 892 db_printf(", "); 893 db_printf("NEED"); 894 } 895 db_printf("}"); 896 } 897 db_printf("\n"); 898 899 if (handlers) 900 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 901 db_dump_intrhand(ih); 902} 903 904/* 905 * Dump data about interrupt handlers 906 */ 907DB_SHOW_COMMAND(intr, db_show_intr) 908{ 909 struct intr_event *ie; 910 int quit, all, verbose; 911 912 quit = 0; 913 verbose = index(modif, 'v') != NULL; 914 all = index(modif, 'a') != NULL; 915 db_setup_paging(db_simple_pager, &quit, db_lines_per_page); 916 TAILQ_FOREACH(ie, &event_list, ie_list) { 917 if (!all && TAILQ_EMPTY(&ie->ie_handlers)) 918 continue; 919 db_dump_intr_event(ie, verbose); 920 } 921} 922#endif /* DDB */ 923 924/* 925 * Start standard software interrupt threads 926 */ 927static void 928start_softintr(void *dummy) 929{ 930 struct proc *p; 931 932 if (swi_add(&clk_intr_event, "clock", softclock, NULL, SWI_CLOCK, 933 INTR_MPSAFE, &softclock_ih) || 934 swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih)) 935 panic("died while creating standard software ithreads"); 936 937 p = clk_intr_event->ie_thread->it_thread->td_proc; 938 PROC_LOCK(p); 939 p->p_flag |= P_NOLOAD; 940 PROC_UNLOCK(p); 941} 942SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr, NULL) 943 944/* 945 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 946 * The data for this machine dependent, and the declarations are in machine 947 * dependent code. The layout of intrnames and intrcnt however is machine 948 * independent. 949 * 950 * We do not know the length of intrcnt and intrnames at compile time, so 951 * calculate things at run time. 952 */ 953static int 954sysctl_intrnames(SYSCTL_HANDLER_ARGS) 955{ 956 return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames, 957 req)); 958} 959 960SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 961 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 962 963static int 964sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 965{ 966 return (sysctl_handle_opaque(oidp, intrcnt, 967 (char *)eintrcnt - (char *)intrcnt, req)); 968} 969 970SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 971 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 972 973#ifdef DDB 974/* 975 * DDB command to dump the interrupt statistics. 976 */ 977DB_SHOW_COMMAND(intrcnt, db_show_intrcnt) 978{ 979 u_long *i; 980 char *cp; 981 int quit; 982 983 cp = intrnames; 984 db_setup_paging(db_simple_pager, &quit, db_lines_per_page); 985 for (i = intrcnt, quit = 0; i != eintrcnt && !quit; i++) { 986 if (*cp == '\0') 987 break; 988 if (*i != 0) 989 db_printf("%s\t%lu\n", cp, *i); 990 cp += strlen(cp) + 1; 991 } 992} 993#endif 994