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