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/11.2/sys/kern/kern_intr.c 333338 2018-05-07 21:42:22Z shurd $"); 29 30 #include "opt_ddb.h" 31 #include "opt_kstack_usage_prof.h" 32 33 #include <sys/param.h> 34 #include <sys/bus.h> 35 #include <sys/conf.h> 36 #include <sys/cpuset.h> 37 #include <sys/rtprio.h> 38 #include <sys/systm.h> 39 #include <sys/interrupt.h> 40 #include <sys/kernel.h> 41 #include <sys/kthread.h> 42 #include <sys/ktr.h> 43 #include <sys/limits.h> 44 #include <sys/lock.h> 45 #include <sys/malloc.h> 46 #include <sys/mutex.h> 47 #include <sys/priv.h> 48 #include <sys/proc.h> 49 #include <sys/random.h> 50 #include <sys/resourcevar.h> 51 #include <sys/sched.h> 52 #include <sys/smp.h> 53 #include <sys/sysctl.h> 54 #include <sys/syslog.h> 55 #include <sys/unistd.h> 56 #include <sys/vmmeter.h> 57 #include <machine/atomic.h> 58 #include <machine/cpu.h> 59 #include <machine/md_var.h> 60 #include <machine/stdarg.h> 61 #ifdef DDB 62 #include <ddb/ddb.h> 63 #include <ddb/db_sym.h> 64 #endif 65 66 /* 67 * Describe an interrupt thread. There is one of these per interrupt event. 68 */ 69 struct intr_thread { 70 struct intr_event *it_event; 71 struct thread *it_thread; /* Kernel thread. */ 72 int it_flags; /* (j) IT_* flags. */ 73 int it_need; /* Needs service. */ 74 }; 75 76 /* Interrupt thread flags kept in it_flags */ 77 #define IT_DEAD 0x000001 /* Thread is waiting to exit. */ 78 #define IT_WAIT 0x000002 /* Thread is waiting for completion. */ 79 80 struct intr_entropy { 81 struct thread *td; 82 uintptr_t event; 83 }; 84 85 struct intr_event *clk_intr_event; 86 struct intr_event *tty_intr_event; 87 void *vm_ih; 88 struct proc *intrproc; 89 90 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads"); 91 92 static int intr_storm_threshold = 1000; 93 SYSCTL_INT(_hw, OID_AUTO, intr_storm_threshold, CTLFLAG_RWTUN, 94 &intr_storm_threshold, 0, 95 "Number of consecutive interrupts before storm protection is enabled"); 96 static TAILQ_HEAD(, intr_event) event_list = 97 TAILQ_HEAD_INITIALIZER(event_list); 98 static struct mtx event_lock; 99 MTX_SYSINIT(intr_event_list, &event_lock, "intr event list", MTX_DEF); 100 101 static void intr_event_update(struct intr_event *ie); 102 #ifdef INTR_FILTER 103 static int intr_event_schedule_thread(struct intr_event *ie, 104 struct intr_thread *ithd); 105 static int intr_filter_loop(struct intr_event *ie, 106 struct trapframe *frame, struct intr_thread **ithd); 107 static struct intr_thread *ithread_create(const char *name, 108 struct intr_handler *ih); 109 #else 110 static int intr_event_schedule_thread(struct intr_event *ie); 111 static struct intr_thread *ithread_create(const char *name); 112 #endif 113 static void ithread_destroy(struct intr_thread *ithread); 114 static void ithread_execute_handlers(struct proc *p, 115 struct intr_event *ie); 116 #ifdef INTR_FILTER 117 static void priv_ithread_execute_handler(struct proc *p, 118 struct intr_handler *ih); 119 #endif 120 static void ithread_loop(void *); 121 static void ithread_update(struct intr_thread *ithd); 122 static void start_softintr(void *); 123 124 /* Map an interrupt type to an ithread priority. */ 125 u_char 126 intr_priority(enum intr_type flags) 127 { 128 u_char pri; 129 130 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET | 131 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV); 132 switch (flags) { 133 case INTR_TYPE_TTY: 134 pri = PI_TTY; 135 break; 136 case INTR_TYPE_BIO: 137 pri = PI_DISK; 138 break; 139 case INTR_TYPE_NET: 140 pri = PI_NET; 141 break; 142 case INTR_TYPE_CAM: 143 pri = PI_DISK; 144 break; 145 case INTR_TYPE_AV: 146 pri = PI_AV; 147 break; 148 case INTR_TYPE_CLK: 149 pri = PI_REALTIME; 150 break; 151 case INTR_TYPE_MISC: 152 pri = PI_DULL; /* don't care */ 153 break; 154 default: 155 /* We didn't specify an interrupt level. */ 156 panic("intr_priority: no interrupt type in flags"); 157 } 158 159 return pri; 160 } 161 162 /* 163 * Update an ithread based on the associated intr_event. 164 */ 165 static void 166 ithread_update(struct intr_thread *ithd) 167 { 168 struct intr_event *ie; 169 struct thread *td; 170 u_char pri; 171 172 ie = ithd->it_event; 173 td = ithd->it_thread; 174 175 /* Determine the overall priority of this event. */ 176 if (TAILQ_EMPTY(&ie->ie_handlers)) 177 pri = PRI_MAX_ITHD; 178 else 179 pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri; 180 181 /* Update name and priority. */ 182 strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name)); 183 #ifdef KTR 184 sched_clear_tdname(td); 185 #endif 186 thread_lock(td); 187 sched_prio(td, pri); 188 thread_unlock(td); 189 } 190 191 /* 192 * Regenerate the full name of an interrupt event and update its priority. 193 */ 194 static void 195 intr_event_update(struct intr_event *ie) 196 { 197 struct intr_handler *ih; 198 char *last; 199 int missed, space; 200 201 /* Start off with no entropy and just the name of the event. */ 202 mtx_assert(&ie->ie_lock, MA_OWNED); 203 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname)); 204 ie->ie_flags &= ~IE_ENTROPY; 205 missed = 0; 206 space = 1; 207 208 /* Run through all the handlers updating values. */ 209 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 210 if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 < 211 sizeof(ie->ie_fullname)) { 212 strcat(ie->ie_fullname, " "); 213 strcat(ie->ie_fullname, ih->ih_name); 214 space = 0; 215 } else 216 missed++; 217 if (ih->ih_flags & IH_ENTROPY) 218 ie->ie_flags |= IE_ENTROPY; 219 } 220 221 /* 222 * If the handler names were too long, add +'s to indicate missing 223 * names. If we run out of room and still have +'s to add, change 224 * the last character from a + to a *. 225 */ 226 last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2]; 227 while (missed-- > 0) { 228 if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) { 229 if (*last == '+') { 230 *last = '*'; 231 break; 232 } else 233 *last = '+'; 234 } else if (space) { 235 strcat(ie->ie_fullname, " +"); 236 space = 0; 237 } else 238 strcat(ie->ie_fullname, "+"); 239 } 240 241 /* 242 * If this event has an ithread, update it's priority and 243 * name. 244 */ 245 if (ie->ie_thread != NULL) 246 ithread_update(ie->ie_thread); 247 CTR2(KTR_INTR, "%s: updated %s", __func__, ie->ie_fullname); 248 } 249 250 int 251 intr_event_create(struct intr_event **event, void *source, int flags, int irq, 252 void (*pre_ithread)(void *), void (*post_ithread)(void *), 253 void (*post_filter)(void *), int (*assign_cpu)(void *, int), 254 const char *fmt, ...) 255 { 256 struct intr_event *ie; 257 va_list ap; 258 259 /* The only valid flag during creation is IE_SOFT. */ 260 if ((flags & ~IE_SOFT) != 0) 261 return (EINVAL); 262 ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO); 263 ie->ie_source = source; 264 ie->ie_pre_ithread = pre_ithread; 265 ie->ie_post_ithread = post_ithread; 266 ie->ie_post_filter = post_filter; 267 ie->ie_assign_cpu = assign_cpu; 268 ie->ie_flags = flags; 269 ie->ie_irq = irq; 270 ie->ie_cpu = NOCPU; 271 TAILQ_INIT(&ie->ie_handlers); 272 mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF); 273 274 va_start(ap, fmt); 275 vsnprintf(ie->ie_name, sizeof(ie->ie_name), fmt, ap); 276 va_end(ap); 277 strlcpy(ie->ie_fullname, ie->ie_name, sizeof(ie->ie_fullname)); 278 mtx_lock(&event_lock); 279 TAILQ_INSERT_TAIL(&event_list, ie, ie_list); 280 mtx_unlock(&event_lock); 281 if (event != NULL) 282 *event = ie; 283 CTR2(KTR_INTR, "%s: created %s", __func__, ie->ie_name); 284 return (0); 285 } 286 287 /* 288 * Bind an interrupt event to the specified CPU. Note that not all 289 * platforms support binding an interrupt to a CPU. For those 290 * platforms this request will fail. Using a cpu id of NOCPU unbinds 291 * the interrupt event. 292 */ 293 static int 294 _intr_event_bind(struct intr_event *ie, int cpu, bool bindirq, bool bindithread) 295 { 296 lwpid_t id; 297 int error; 298 299 /* Need a CPU to bind to. */ 300 if (cpu != NOCPU && CPU_ABSENT(cpu)) 301 return (EINVAL); 302 303 if (ie->ie_assign_cpu == NULL) 304 return (EOPNOTSUPP); 305 306 error = priv_check(curthread, PRIV_SCHED_CPUSET_INTR); 307 if (error) 308 return (error); 309 310 /* 311 * If we have any ithreads try to set their mask first to verify 312 * permissions, etc. 313 */ 314 if (bindithread) { 315 mtx_lock(&ie->ie_lock); 316 if (ie->ie_thread != NULL) { 317 id = ie->ie_thread->it_thread->td_tid; 318 mtx_unlock(&ie->ie_lock); 319 error = cpuset_setithread(id, cpu); 320 if (error) 321 return (error); 322 } else 323 mtx_unlock(&ie->ie_lock); 324 } 325 if (bindirq) 326 error = ie->ie_assign_cpu(ie->ie_source, cpu); 327 if (error) { 328 if (bindithread) { 329 mtx_lock(&ie->ie_lock); 330 if (ie->ie_thread != NULL) { 331 cpu = ie->ie_cpu; 332 id = ie->ie_thread->it_thread->td_tid; 333 mtx_unlock(&ie->ie_lock); 334 (void)cpuset_setithread(id, cpu); 335 } else 336 mtx_unlock(&ie->ie_lock); 337 } 338 return (error); 339 } 340 341 if (bindirq) { 342 mtx_lock(&ie->ie_lock); 343 ie->ie_cpu = cpu; 344 mtx_unlock(&ie->ie_lock); 345 } 346 347 return (error); 348 } 349 350 /* 351 * Bind an interrupt event to the specified CPU. For supported platforms, any 352 * associated ithreads as well as the primary interrupt context will be bound 353 * to the specificed CPU. 354 */ 355 int 356 intr_event_bind(struct intr_event *ie, int cpu) 357 { 358 359 return (_intr_event_bind(ie, cpu, true, true)); 360 } 361 362 /* 363 * Bind an interrupt event to the specified CPU, but do not bind associated 364 * ithreads. 365 */ 366 int 367 intr_event_bind_irqonly(struct intr_event *ie, int cpu) 368 { 369 370 return (_intr_event_bind(ie, cpu, true, false)); 371 } 372 373 /* 374 * Bind an interrupt event's ithread to the specified CPU. 375 */ 376 int 377 intr_event_bind_ithread(struct intr_event *ie, int cpu) 378 { 379 380 return (_intr_event_bind(ie, cpu, false, true)); 381 } 382 383 static struct intr_event * 384 intr_lookup(int irq) 385 { 386 struct intr_event *ie; 387 388 mtx_lock(&event_lock); 389 TAILQ_FOREACH(ie, &event_list, ie_list) 390 if (ie->ie_irq == irq && 391 (ie->ie_flags & IE_SOFT) == 0 && 392 TAILQ_FIRST(&ie->ie_handlers) != NULL) 393 break; 394 mtx_unlock(&event_lock); 395 return (ie); 396 } 397 398 int 399 intr_setaffinity(int irq, int mode, void *m) 400 { 401 struct intr_event *ie; 402 cpuset_t *mask; 403 int cpu, n; 404 405 mask = m; 406 cpu = NOCPU; 407 /* 408 * If we're setting all cpus we can unbind. Otherwise make sure 409 * only one cpu is in the set. 410 */ 411 if (CPU_CMP(cpuset_root, mask)) { 412 for (n = 0; n < CPU_SETSIZE; n++) { 413 if (!CPU_ISSET(n, mask)) 414 continue; 415 if (cpu != NOCPU) 416 return (EINVAL); 417 cpu = n; 418 } 419 } 420 ie = intr_lookup(irq); 421 if (ie == NULL) 422 return (ESRCH); 423 switch (mode) { 424 case CPU_WHICH_IRQ: 425 return (intr_event_bind(ie, cpu)); 426 case CPU_WHICH_INTRHANDLER: 427 return (intr_event_bind_irqonly(ie, cpu)); 428 case CPU_WHICH_ITHREAD: 429 return (intr_event_bind_ithread(ie, cpu)); 430 default: 431 return (EINVAL); 432 } 433 } 434 435 int 436 intr_getaffinity(int irq, int mode, void *m) 437 { 438 struct intr_event *ie; 439 struct thread *td; 440 struct proc *p; 441 cpuset_t *mask; 442 lwpid_t id; 443 int error; 444 445 mask = m; 446 ie = intr_lookup(irq); 447 if (ie == NULL) 448 return (ESRCH); 449 450 error = 0; 451 CPU_ZERO(mask); 452 switch (mode) { 453 case CPU_WHICH_IRQ: 454 case CPU_WHICH_INTRHANDLER: 455 mtx_lock(&ie->ie_lock); 456 if (ie->ie_cpu == NOCPU) 457 CPU_COPY(cpuset_root, mask); 458 else 459 CPU_SET(ie->ie_cpu, mask); 460 mtx_unlock(&ie->ie_lock); 461 break; 462 case CPU_WHICH_ITHREAD: 463 mtx_lock(&ie->ie_lock); 464 if (ie->ie_thread == NULL) { 465 mtx_unlock(&ie->ie_lock); 466 CPU_COPY(cpuset_root, mask); 467 } else { 468 id = ie->ie_thread->it_thread->td_tid; 469 mtx_unlock(&ie->ie_lock); 470 error = cpuset_which(CPU_WHICH_TID, id, &p, &td, NULL); 471 if (error != 0) 472 return (error); 473 CPU_COPY(&td->td_cpuset->cs_mask, mask); 474 PROC_UNLOCK(p); 475 } 476 default: 477 return (EINVAL); 478 } 479 return (0); 480 } 481 482 int 483 intr_event_destroy(struct intr_event *ie) 484 { 485 486 mtx_lock(&event_lock); 487 mtx_lock(&ie->ie_lock); 488 if (!TAILQ_EMPTY(&ie->ie_handlers)) { 489 mtx_unlock(&ie->ie_lock); 490 mtx_unlock(&event_lock); 491 return (EBUSY); 492 } 493 TAILQ_REMOVE(&event_list, ie, ie_list); 494 #ifndef notyet 495 if (ie->ie_thread != NULL) { 496 ithread_destroy(ie->ie_thread); 497 ie->ie_thread = NULL; 498 } 499 #endif 500 mtx_unlock(&ie->ie_lock); 501 mtx_unlock(&event_lock); 502 mtx_destroy(&ie->ie_lock); 503 free(ie, M_ITHREAD); 504 return (0); 505 } 506 507 #ifndef INTR_FILTER 508 static struct intr_thread * 509 ithread_create(const char *name) 510 { 511 struct intr_thread *ithd; 512 struct thread *td; 513 int error; 514 515 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO); 516 517 error = kproc_kthread_add(ithread_loop, ithd, &intrproc, 518 &td, RFSTOPPED | RFHIGHPID, 519 0, "intr", "%s", name); 520 if (error) 521 panic("kproc_create() failed with %d", error); 522 thread_lock(td); 523 sched_class(td, PRI_ITHD); 524 TD_SET_IWAIT(td); 525 thread_unlock(td); 526 td->td_pflags |= TDP_ITHREAD; 527 ithd->it_thread = td; 528 CTR2(KTR_INTR, "%s: created %s", __func__, name); 529 return (ithd); 530 } 531 #else 532 static struct intr_thread * 533 ithread_create(const char *name, struct intr_handler *ih) 534 { 535 struct intr_thread *ithd; 536 struct thread *td; 537 int error; 538 539 ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO); 540 541 error = kproc_kthread_add(ithread_loop, ih, &intrproc, 542 &td, RFSTOPPED | RFHIGHPID, 543 0, "intr", "%s", name); 544 if (error) 545 panic("kproc_create() failed with %d", error); 546 thread_lock(td); 547 sched_class(td, PRI_ITHD); 548 TD_SET_IWAIT(td); 549 thread_unlock(td); 550 td->td_pflags |= TDP_ITHREAD; 551 ithd->it_thread = td; 552 CTR2(KTR_INTR, "%s: created %s", __func__, name); 553 return (ithd); 554 } 555 #endif 556 557 static void 558 ithread_destroy(struct intr_thread *ithread) 559 { 560 struct thread *td; 561 562 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_event->ie_name); 563 td = ithread->it_thread; 564 thread_lock(td); 565 ithread->it_flags |= IT_DEAD; 566 if (TD_AWAITING_INTR(td)) { 567 TD_CLR_IWAIT(td); 568 sched_add(td, SRQ_INTR); 569 } 570 thread_unlock(td); 571 } 572 573 #ifndef INTR_FILTER 574 int 575 intr_event_add_handler(struct intr_event *ie, const char *name, 576 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri, 577 enum intr_type flags, void **cookiep) 578 { 579 struct intr_handler *ih, *temp_ih; 580 struct intr_thread *it; 581 582 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL)) 583 return (EINVAL); 584 585 /* Allocate and populate an interrupt handler structure. */ 586 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO); 587 ih->ih_filter = filter; 588 ih->ih_handler = handler; 589 ih->ih_argument = arg; 590 strlcpy(ih->ih_name, name, sizeof(ih->ih_name)); 591 ih->ih_event = ie; 592 ih->ih_pri = pri; 593 if (flags & INTR_EXCL) 594 ih->ih_flags = IH_EXCLUSIVE; 595 if (flags & INTR_MPSAFE) 596 ih->ih_flags |= IH_MPSAFE; 597 if (flags & INTR_ENTROPY) 598 ih->ih_flags |= IH_ENTROPY; 599 600 /* We can only have one exclusive handler in a event. */ 601 mtx_lock(&ie->ie_lock); 602 if (!TAILQ_EMPTY(&ie->ie_handlers)) { 603 if ((flags & INTR_EXCL) || 604 (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) { 605 mtx_unlock(&ie->ie_lock); 606 free(ih, M_ITHREAD); 607 return (EINVAL); 608 } 609 } 610 611 /* Create a thread if we need one. */ 612 while (ie->ie_thread == NULL && handler != NULL) { 613 if (ie->ie_flags & IE_ADDING_THREAD) 614 msleep(ie, &ie->ie_lock, 0, "ithread", 0); 615 else { 616 ie->ie_flags |= IE_ADDING_THREAD; 617 mtx_unlock(&ie->ie_lock); 618 it = ithread_create("intr: newborn"); 619 mtx_lock(&ie->ie_lock); 620 ie->ie_flags &= ~IE_ADDING_THREAD; 621 ie->ie_thread = it; 622 it->it_event = ie; 623 ithread_update(it); 624 wakeup(ie); 625 } 626 } 627 628 /* Add the new handler to the event in priority order. */ 629 TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { 630 if (temp_ih->ih_pri > ih->ih_pri) 631 break; 632 } 633 if (temp_ih == NULL) 634 TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); 635 else 636 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); 637 intr_event_update(ie); 638 639 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, 640 ie->ie_name); 641 mtx_unlock(&ie->ie_lock); 642 643 if (cookiep != NULL) 644 *cookiep = ih; 645 return (0); 646 } 647 #else 648 int 649 intr_event_add_handler(struct intr_event *ie, const char *name, 650 driver_filter_t filter, driver_intr_t handler, void *arg, u_char pri, 651 enum intr_type flags, void **cookiep) 652 { 653 struct intr_handler *ih, *temp_ih; 654 struct intr_thread *it; 655 656 if (ie == NULL || name == NULL || (handler == NULL && filter == NULL)) 657 return (EINVAL); 658 659 /* Allocate and populate an interrupt handler structure. */ 660 ih = malloc(sizeof(struct intr_handler), M_ITHREAD, M_WAITOK | M_ZERO); 661 ih->ih_filter = filter; 662 ih->ih_handler = handler; 663 ih->ih_argument = arg; 664 strlcpy(ih->ih_name, name, sizeof(ih->ih_name)); 665 ih->ih_event = ie; 666 ih->ih_pri = pri; 667 if (flags & INTR_EXCL) 668 ih->ih_flags = IH_EXCLUSIVE; 669 if (flags & INTR_MPSAFE) 670 ih->ih_flags |= IH_MPSAFE; 671 if (flags & INTR_ENTROPY) 672 ih->ih_flags |= IH_ENTROPY; 673 674 /* We can only have one exclusive handler in a event. */ 675 mtx_lock(&ie->ie_lock); 676 if (!TAILQ_EMPTY(&ie->ie_handlers)) { 677 if ((flags & INTR_EXCL) || 678 (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) { 679 mtx_unlock(&ie->ie_lock); 680 free(ih, M_ITHREAD); 681 return (EINVAL); 682 } 683 } 684 685 /* For filtered handlers, create a private ithread to run on. */ 686 if (filter != NULL && handler != NULL) { 687 mtx_unlock(&ie->ie_lock); 688 it = ithread_create("intr: newborn", ih); 689 mtx_lock(&ie->ie_lock); 690 it->it_event = ie; 691 ih->ih_thread = it; 692 ithread_update(it); /* XXX - do we really need this?!?!? */ 693 } else { /* Create the global per-event thread if we need one. */ 694 while (ie->ie_thread == NULL && handler != NULL) { 695 if (ie->ie_flags & IE_ADDING_THREAD) 696 msleep(ie, &ie->ie_lock, 0, "ithread", 0); 697 else { 698 ie->ie_flags |= IE_ADDING_THREAD; 699 mtx_unlock(&ie->ie_lock); 700 it = ithread_create("intr: newborn", ih); 701 mtx_lock(&ie->ie_lock); 702 ie->ie_flags &= ~IE_ADDING_THREAD; 703 ie->ie_thread = it; 704 it->it_event = ie; 705 ithread_update(it); 706 wakeup(ie); 707 } 708 } 709 } 710 711 /* Add the new handler to the event in priority order. */ 712 TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { 713 if (temp_ih->ih_pri > ih->ih_pri) 714 break; 715 } 716 if (temp_ih == NULL) 717 TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); 718 else 719 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); 720 intr_event_update(ie); 721 722 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, 723 ie->ie_name); 724 mtx_unlock(&ie->ie_lock); 725 726 if (cookiep != NULL) 727 *cookiep = ih; 728 return (0); 729 } 730 #endif 731 732 /* 733 * Append a description preceded by a ':' to the name of the specified 734 * interrupt handler. 735 */ 736 int 737 intr_event_describe_handler(struct intr_event *ie, void *cookie, 738 const char *descr) 739 { 740 struct intr_handler *ih; 741 size_t space; 742 char *start; 743 744 mtx_lock(&ie->ie_lock); 745 #ifdef INVARIANTS 746 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 747 if (ih == cookie) 748 break; 749 } 750 if (ih == NULL) { 751 mtx_unlock(&ie->ie_lock); 752 panic("handler %p not found in interrupt event %p", cookie, ie); 753 } 754 #endif 755 ih = cookie; 756 757 /* 758 * Look for an existing description by checking for an 759 * existing ":". This assumes device names do not include 760 * colons. If one is found, prepare to insert the new 761 * description at that point. If one is not found, find the 762 * end of the name to use as the insertion point. 763 */ 764 start = strchr(ih->ih_name, ':'); 765 if (start == NULL) 766 start = strchr(ih->ih_name, 0); 767 768 /* 769 * See if there is enough remaining room in the string for the 770 * description + ":". The "- 1" leaves room for the trailing 771 * '\0'. The "+ 1" accounts for the colon. 772 */ 773 space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1; 774 if (strlen(descr) + 1 > space) { 775 mtx_unlock(&ie->ie_lock); 776 return (ENOSPC); 777 } 778 779 /* Append a colon followed by the description. */ 780 *start = ':'; 781 strcpy(start + 1, descr); 782 intr_event_update(ie); 783 mtx_unlock(&ie->ie_lock); 784 return (0); 785 } 786 787 /* 788 * Return the ie_source field from the intr_event an intr_handler is 789 * associated with. 790 */ 791 void * 792 intr_handler_source(void *cookie) 793 { 794 struct intr_handler *ih; 795 struct intr_event *ie; 796 797 ih = (struct intr_handler *)cookie; 798 if (ih == NULL) 799 return (NULL); 800 ie = ih->ih_event; 801 KASSERT(ie != NULL, 802 ("interrupt handler \"%s\" has a NULL interrupt event", 803 ih->ih_name)); 804 return (ie->ie_source); 805 } 806 807 /* 808 * Sleep until an ithread finishes executing an interrupt handler. 809 * 810 * XXX Doesn't currently handle interrupt filters or fast interrupt 811 * handlers. This is intended for compatibility with linux drivers 812 * only. Do not use in BSD code. 813 */ 814 void 815 _intr_drain(int irq) 816 { 817 struct intr_event *ie; 818 struct intr_thread *ithd; 819 struct thread *td; 820 821 ie = intr_lookup(irq); 822 if (ie == NULL) 823 return; 824 if (ie->ie_thread == NULL) 825 return; 826 ithd = ie->ie_thread; 827 td = ithd->it_thread; 828 /* 829 * We set the flag and wait for it to be cleared to avoid 830 * long delays with potentially busy interrupt handlers 831 * were we to only sample TD_AWAITING_INTR() every tick. 832 */ 833 thread_lock(td); 834 if (!TD_AWAITING_INTR(td)) { 835 ithd->it_flags |= IT_WAIT; 836 while (ithd->it_flags & IT_WAIT) { 837 thread_unlock(td); 838 pause("idrain", 1); 839 thread_lock(td); 840 } 841 } 842 thread_unlock(td); 843 return; 844 } 845 846 847 #ifndef INTR_FILTER 848 int 849 intr_event_remove_handler(void *cookie) 850 { 851 struct intr_handler *handler = (struct intr_handler *)cookie; 852 struct intr_event *ie; 853 #ifdef INVARIANTS 854 struct intr_handler *ih; 855 #endif 856 #ifdef notyet 857 int dead; 858 #endif 859 860 if (handler == NULL) 861 return (EINVAL); 862 ie = handler->ih_event; 863 KASSERT(ie != NULL, 864 ("interrupt handler \"%s\" has a NULL interrupt event", 865 handler->ih_name)); 866 mtx_lock(&ie->ie_lock); 867 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name, 868 ie->ie_name); 869 #ifdef INVARIANTS 870 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 871 if (ih == handler) 872 goto ok; 873 mtx_unlock(&ie->ie_lock); 874 panic("interrupt handler \"%s\" not found in interrupt event \"%s\"", 875 ih->ih_name, ie->ie_name); 876 ok: 877 #endif 878 /* 879 * If there is no ithread, then just remove the handler and return. 880 * XXX: Note that an INTR_FAST handler might be running on another 881 * CPU! 882 */ 883 if (ie->ie_thread == NULL) { 884 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 885 mtx_unlock(&ie->ie_lock); 886 free(handler, M_ITHREAD); 887 return (0); 888 } 889 890 /* 891 * If the interrupt thread is already running, then just mark this 892 * handler as being dead and let the ithread do the actual removal. 893 * 894 * During a cold boot while cold is set, msleep() does not sleep, 895 * so we have to remove the handler here rather than letting the 896 * thread do it. 897 */ 898 thread_lock(ie->ie_thread->it_thread); 899 if (!TD_AWAITING_INTR(ie->ie_thread->it_thread) && !cold) { 900 handler->ih_flags |= IH_DEAD; 901 902 /* 903 * Ensure that the thread will process the handler list 904 * again and remove this handler if it has already passed 905 * it on the list. 906 * 907 * The release part of the following store ensures 908 * that the update of ih_flags is ordered before the 909 * it_need setting. See the comment before 910 * atomic_cmpset_acq(&ithd->it_need, ...) operation in 911 * the ithread_execute_handlers(). 912 */ 913 atomic_store_rel_int(&ie->ie_thread->it_need, 1); 914 } else 915 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 916 thread_unlock(ie->ie_thread->it_thread); 917 while (handler->ih_flags & IH_DEAD) 918 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0); 919 intr_event_update(ie); 920 #ifdef notyet 921 /* 922 * XXX: This could be bad in the case of ppbus(8). Also, I think 923 * this could lead to races of stale data when servicing an 924 * interrupt. 925 */ 926 dead = 1; 927 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 928 if (!(ih->ih_flags & IH_FAST)) { 929 dead = 0; 930 break; 931 } 932 } 933 if (dead) { 934 ithread_destroy(ie->ie_thread); 935 ie->ie_thread = NULL; 936 } 937 #endif 938 mtx_unlock(&ie->ie_lock); 939 free(handler, M_ITHREAD); 940 return (0); 941 } 942 943 static int 944 intr_event_schedule_thread(struct intr_event *ie) 945 { 946 struct intr_entropy entropy; 947 struct intr_thread *it; 948 struct thread *td; 949 struct thread *ctd; 950 struct proc *p; 951 952 /* 953 * If no ithread or no handlers, then we have a stray interrupt. 954 */ 955 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) || 956 ie->ie_thread == NULL) 957 return (EINVAL); 958 959 ctd = curthread; 960 it = ie->ie_thread; 961 td = it->it_thread; 962 p = td->td_proc; 963 964 /* 965 * If any of the handlers for this ithread claim to be good 966 * sources of entropy, then gather some. 967 */ 968 if (ie->ie_flags & IE_ENTROPY) { 969 entropy.event = (uintptr_t)ie; 970 entropy.td = ctd; 971 random_harvest_queue(&entropy, sizeof(entropy), 2, RANDOM_INTERRUPT); 972 } 973 974 KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name)); 975 976 /* 977 * Set it_need to tell the thread to keep running if it is already 978 * running. Then, lock the thread and see if we actually need to 979 * put it on the runqueue. 980 * 981 * Use store_rel to arrange that the store to ih_need in 982 * swi_sched() is before the store to it_need and prepare for 983 * transfer of this order to loads in the ithread. 984 */ 985 atomic_store_rel_int(&it->it_need, 1); 986 thread_lock(td); 987 if (TD_AWAITING_INTR(td)) { 988 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid, 989 td->td_name); 990 TD_CLR_IWAIT(td); 991 sched_add(td, SRQ_INTR); 992 } else { 993 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d", 994 __func__, p->p_pid, td->td_name, it->it_need, td->td_state); 995 } 996 thread_unlock(td); 997 998 return (0); 999 } 1000 #else 1001 int 1002 intr_event_remove_handler(void *cookie) 1003 { 1004 struct intr_handler *handler = (struct intr_handler *)cookie; 1005 struct intr_event *ie; 1006 struct intr_thread *it; 1007 #ifdef INVARIANTS 1008 struct intr_handler *ih; 1009 #endif 1010 #ifdef notyet 1011 int dead; 1012 #endif 1013 1014 if (handler == NULL) 1015 return (EINVAL); 1016 ie = handler->ih_event; 1017 KASSERT(ie != NULL, 1018 ("interrupt handler \"%s\" has a NULL interrupt event", 1019 handler->ih_name)); 1020 mtx_lock(&ie->ie_lock); 1021 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name, 1022 ie->ie_name); 1023 #ifdef INVARIANTS 1024 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 1025 if (ih == handler) 1026 goto ok; 1027 mtx_unlock(&ie->ie_lock); 1028 panic("interrupt handler \"%s\" not found in interrupt event \"%s\"", 1029 ih->ih_name, ie->ie_name); 1030 ok: 1031 #endif 1032 /* 1033 * If there are no ithreads (per event and per handler), then 1034 * just remove the handler and return. 1035 * XXX: Note that an INTR_FAST handler might be running on another CPU! 1036 */ 1037 if (ie->ie_thread == NULL && handler->ih_thread == NULL) { 1038 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 1039 mtx_unlock(&ie->ie_lock); 1040 free(handler, M_ITHREAD); 1041 return (0); 1042 } 1043 1044 /* Private or global ithread? */ 1045 it = (handler->ih_thread) ? handler->ih_thread : ie->ie_thread; 1046 /* 1047 * If the interrupt thread is already running, then just mark this 1048 * handler as being dead and let the ithread do the actual removal. 1049 * 1050 * During a cold boot while cold is set, msleep() does not sleep, 1051 * so we have to remove the handler here rather than letting the 1052 * thread do it. 1053 */ 1054 thread_lock(it->it_thread); 1055 if (!TD_AWAITING_INTR(it->it_thread) && !cold) { 1056 handler->ih_flags |= IH_DEAD; 1057 1058 /* 1059 * Ensure that the thread will process the handler list 1060 * again and remove this handler if it has already passed 1061 * it on the list. 1062 * 1063 * The release part of the following store ensures 1064 * that the update of ih_flags is ordered before the 1065 * it_need setting. See the comment before 1066 * atomic_cmpset_acq(&ithd->it_need, ...) operation in 1067 * the ithread_execute_handlers(). 1068 */ 1069 atomic_store_rel_int(&it->it_need, 1); 1070 } else 1071 TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next); 1072 thread_unlock(it->it_thread); 1073 while (handler->ih_flags & IH_DEAD) 1074 msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0); 1075 /* 1076 * At this point, the handler has been disconnected from the event, 1077 * so we can kill the private ithread if any. 1078 */ 1079 if (handler->ih_thread) { 1080 ithread_destroy(handler->ih_thread); 1081 handler->ih_thread = NULL; 1082 } 1083 intr_event_update(ie); 1084 #ifdef notyet 1085 /* 1086 * XXX: This could be bad in the case of ppbus(8). Also, I think 1087 * this could lead to races of stale data when servicing an 1088 * interrupt. 1089 */ 1090 dead = 1; 1091 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 1092 if (handler != NULL) { 1093 dead = 0; 1094 break; 1095 } 1096 } 1097 if (dead) { 1098 ithread_destroy(ie->ie_thread); 1099 ie->ie_thread = NULL; 1100 } 1101 #endif 1102 mtx_unlock(&ie->ie_lock); 1103 free(handler, M_ITHREAD); 1104 return (0); 1105 } 1106 1107 static int 1108 intr_event_schedule_thread(struct intr_event *ie, struct intr_thread *it) 1109 { 1110 struct intr_entropy entropy; 1111 struct thread *td; 1112 struct thread *ctd; 1113 struct proc *p; 1114 1115 /* 1116 * If no ithread or no handlers, then we have a stray interrupt. 1117 */ 1118 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) || it == NULL) 1119 return (EINVAL); 1120 1121 ctd = curthread; 1122 td = it->it_thread; 1123 p = td->td_proc; 1124 1125 /* 1126 * If any of the handlers for this ithread claim to be good 1127 * sources of entropy, then gather some. 1128 */ 1129 if (ie->ie_flags & IE_ENTROPY) { 1130 entropy.event = (uintptr_t)ie; 1131 entropy.td = ctd; 1132 random_harvest_queue(&entropy, sizeof(entropy), 2, RANDOM_INTERRUPT); 1133 } 1134 1135 KASSERT(p != NULL, ("ithread %s has no process", ie->ie_name)); 1136 1137 /* 1138 * Set it_need to tell the thread to keep running if it is already 1139 * running. Then, lock the thread and see if we actually need to 1140 * put it on the runqueue. 1141 * 1142 * Use store_rel to arrange that the store to ih_need in 1143 * swi_sched() is before the store to it_need and prepare for 1144 * transfer of this order to loads in the ithread. 1145 */ 1146 atomic_store_rel_int(&it->it_need, 1); 1147 thread_lock(td); 1148 if (TD_AWAITING_INTR(td)) { 1149 CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid, 1150 td->td_name); 1151 TD_CLR_IWAIT(td); 1152 sched_add(td, SRQ_INTR); 1153 } else { 1154 CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d", 1155 __func__, p->p_pid, td->td_name, it->it_need, td->td_state); 1156 } 1157 thread_unlock(td); 1158 1159 return (0); 1160 } 1161 #endif 1162 1163 /* 1164 * Allow interrupt event binding for software interrupt handlers -- a no-op, 1165 * since interrupts are generated in software rather than being directed by 1166 * a PIC. 1167 */ 1168 static int 1169 swi_assign_cpu(void *arg, int cpu) 1170 { 1171 1172 return (0); 1173 } 1174 1175 /* 1176 * Add a software interrupt handler to a specified event. If a given event 1177 * is not specified, then a new event is created. 1178 */ 1179 int 1180 swi_add(struct intr_event **eventp, const char *name, driver_intr_t handler, 1181 void *arg, int pri, enum intr_type flags, void **cookiep) 1182 { 1183 struct intr_event *ie; 1184 int error; 1185 1186 if (flags & INTR_ENTROPY) 1187 return (EINVAL); 1188 1189 ie = (eventp != NULL) ? *eventp : NULL; 1190 1191 if (ie != NULL) { 1192 if (!(ie->ie_flags & IE_SOFT)) 1193 return (EINVAL); 1194 } else { 1195 error = intr_event_create(&ie, NULL, IE_SOFT, 0, 1196 NULL, NULL, NULL, swi_assign_cpu, "swi%d:", pri); 1197 if (error) 1198 return (error); 1199 if (eventp != NULL) 1200 *eventp = ie; 1201 } 1202 error = intr_event_add_handler(ie, name, NULL, handler, arg, 1203 PI_SWI(pri), flags, cookiep); 1204 return (error); 1205 } 1206 1207 /* 1208 * Schedule a software interrupt thread. 1209 */ 1210 void 1211 swi_sched(void *cookie, int flags) 1212 { 1213 struct intr_handler *ih = (struct intr_handler *)cookie; 1214 struct intr_event *ie = ih->ih_event; 1215 struct intr_entropy entropy; 1216 int error; 1217 1218 CTR3(KTR_INTR, "swi_sched: %s %s need=%d", ie->ie_name, ih->ih_name, 1219 ih->ih_need); 1220 1221 entropy.event = (uintptr_t)ih; 1222 entropy.td = curthread; 1223 random_harvest_queue(&entropy, sizeof(entropy), 1, RANDOM_SWI); 1224 1225 /* 1226 * Set ih_need for this handler so that if the ithread is already 1227 * running it will execute this handler on the next pass. Otherwise, 1228 * it will execute it the next time it runs. 1229 */ 1230 ih->ih_need = 1; 1231 1232 if (!(flags & SWI_DELAY)) { 1233 PCPU_INC(cnt.v_soft); 1234 #ifdef INTR_FILTER 1235 error = intr_event_schedule_thread(ie, ie->ie_thread); 1236 #else 1237 error = intr_event_schedule_thread(ie); 1238 #endif 1239 KASSERT(error == 0, ("stray software interrupt")); 1240 } 1241 } 1242 1243 /* 1244 * Remove a software interrupt handler. Currently this code does not 1245 * remove the associated interrupt event if it becomes empty. Calling code 1246 * may do so manually via intr_event_destroy(), but that's not really 1247 * an optimal interface. 1248 */ 1249 int 1250 swi_remove(void *cookie) 1251 { 1252 1253 return (intr_event_remove_handler(cookie)); 1254 } 1255 1256 #ifdef INTR_FILTER 1257 static void 1258 priv_ithread_execute_handler(struct proc *p, struct intr_handler *ih) 1259 { 1260 struct intr_event *ie; 1261 1262 ie = ih->ih_event; 1263 /* 1264 * If this handler is marked for death, remove it from 1265 * the list of handlers and wake up the sleeper. 1266 */ 1267 if (ih->ih_flags & IH_DEAD) { 1268 mtx_lock(&ie->ie_lock); 1269 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next); 1270 ih->ih_flags &= ~IH_DEAD; 1271 wakeup(ih); 1272 mtx_unlock(&ie->ie_lock); 1273 return; 1274 } 1275 1276 /* Execute this handler. */ 1277 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x", 1278 __func__, p->p_pid, (void *)ih->ih_handler, ih->ih_argument, 1279 ih->ih_name, ih->ih_flags); 1280 1281 if (!(ih->ih_flags & IH_MPSAFE)) 1282 mtx_lock(&Giant); 1283 ih->ih_handler(ih->ih_argument); 1284 if (!(ih->ih_flags & IH_MPSAFE)) 1285 mtx_unlock(&Giant); 1286 } 1287 #endif 1288 1289 /* 1290 * This is a public function for use by drivers that mux interrupt 1291 * handlers for child devices from their interrupt handler. 1292 */ 1293 void 1294 intr_event_execute_handlers(struct proc *p, struct intr_event *ie) 1295 { 1296 struct intr_handler *ih, *ihn; 1297 1298 TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) { 1299 /* 1300 * If this handler is marked for death, remove it from 1301 * the list of handlers and wake up the sleeper. 1302 */ 1303 if (ih->ih_flags & IH_DEAD) { 1304 mtx_lock(&ie->ie_lock); 1305 TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next); 1306 ih->ih_flags &= ~IH_DEAD; 1307 wakeup(ih); 1308 mtx_unlock(&ie->ie_lock); 1309 continue; 1310 } 1311 1312 /* Skip filter only handlers */ 1313 if (ih->ih_handler == NULL) 1314 continue; 1315 1316 /* 1317 * For software interrupt threads, we only execute 1318 * handlers that have their need flag set. Hardware 1319 * interrupt threads always invoke all of their handlers. 1320 * 1321 * ih_need can only be 0 or 1. Failed cmpset below 1322 * means that there is no request to execute handlers, 1323 * so a retry of the cmpset is not needed. 1324 */ 1325 if ((ie->ie_flags & IE_SOFT) != 0 && 1326 atomic_cmpset_int(&ih->ih_need, 1, 0) == 0) 1327 continue; 1328 1329 /* Execute this handler. */ 1330 CTR6(KTR_INTR, "%s: pid %d exec %p(%p) for %s flg=%x", 1331 __func__, p->p_pid, (void *)ih->ih_handler, 1332 ih->ih_argument, ih->ih_name, ih->ih_flags); 1333 1334 if (!(ih->ih_flags & IH_MPSAFE)) 1335 mtx_lock(&Giant); 1336 ih->ih_handler(ih->ih_argument); 1337 if (!(ih->ih_flags & IH_MPSAFE)) 1338 mtx_unlock(&Giant); 1339 } 1340 } 1341 1342 static void 1343 ithread_execute_handlers(struct proc *p, struct intr_event *ie) 1344 { 1345 1346 /* Interrupt handlers should not sleep. */ 1347 if (!(ie->ie_flags & IE_SOFT)) 1348 THREAD_NO_SLEEPING(); 1349 intr_event_execute_handlers(p, ie); 1350 if (!(ie->ie_flags & IE_SOFT)) 1351 THREAD_SLEEPING_OK(); 1352 1353 /* 1354 * Interrupt storm handling: 1355 * 1356 * If this interrupt source is currently storming, then throttle 1357 * it to only fire the handler once per clock tick. 1358 * 1359 * If this interrupt source is not currently storming, but the 1360 * number of back to back interrupts exceeds the storm threshold, 1361 * then enter storming mode. 1362 */ 1363 if (intr_storm_threshold != 0 && ie->ie_count >= intr_storm_threshold && 1364 !(ie->ie_flags & IE_SOFT)) { 1365 /* Report the message only once every second. */ 1366 if (ppsratecheck(&ie->ie_warntm, &ie->ie_warncnt, 1)) { 1367 printf( 1368 "interrupt storm detected on \"%s\"; throttling interrupt source\n", 1369 ie->ie_name); 1370 } 1371 pause("istorm", 1); 1372 } else 1373 ie->ie_count++; 1374 1375 /* 1376 * Now that all the handlers have had a chance to run, reenable 1377 * the interrupt source. 1378 */ 1379 if (ie->ie_post_ithread != NULL) 1380 ie->ie_post_ithread(ie->ie_source); 1381 } 1382 1383 #ifndef INTR_FILTER 1384 /* 1385 * This is the main code for interrupt threads. 1386 */ 1387 static void 1388 ithread_loop(void *arg) 1389 { 1390 struct intr_thread *ithd; 1391 struct intr_event *ie; 1392 struct thread *td; 1393 struct proc *p; 1394 int wake; 1395 1396 td = curthread; 1397 p = td->td_proc; 1398 ithd = (struct intr_thread *)arg; 1399 KASSERT(ithd->it_thread == td, 1400 ("%s: ithread and proc linkage out of sync", __func__)); 1401 ie = ithd->it_event; 1402 ie->ie_count = 0; 1403 wake = 0; 1404 1405 /* 1406 * As long as we have interrupts outstanding, go through the 1407 * list of handlers, giving each one a go at it. 1408 */ 1409 for (;;) { 1410 /* 1411 * If we are an orphaned thread, then just die. 1412 */ 1413 if (ithd->it_flags & IT_DEAD) { 1414 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__, 1415 p->p_pid, td->td_name); 1416 free(ithd, M_ITHREAD); 1417 kthread_exit(); 1418 } 1419 1420 /* 1421 * Service interrupts. If another interrupt arrives while 1422 * we are running, it will set it_need to note that we 1423 * should make another pass. 1424 * 1425 * The load_acq part of the following cmpset ensures 1426 * that the load of ih_need in ithread_execute_handlers() 1427 * is ordered after the load of it_need here. 1428 */ 1429 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) 1430 ithread_execute_handlers(p, ie); 1431 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); 1432 mtx_assert(&Giant, MA_NOTOWNED); 1433 1434 /* 1435 * Processed all our interrupts. Now get the sched 1436 * lock. This may take a while and it_need may get 1437 * set again, so we have to check it again. 1438 */ 1439 thread_lock(td); 1440 if (atomic_load_acq_int(&ithd->it_need) == 0 && 1441 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) { 1442 TD_SET_IWAIT(td); 1443 ie->ie_count = 0; 1444 mi_switch(SW_VOL | SWT_IWAIT, NULL); 1445 } 1446 if (ithd->it_flags & IT_WAIT) { 1447 wake = 1; 1448 ithd->it_flags &= ~IT_WAIT; 1449 } 1450 thread_unlock(td); 1451 if (wake) { 1452 wakeup(ithd); 1453 wake = 0; 1454 } 1455 } 1456 } 1457 1458 /* 1459 * Main interrupt handling body. 1460 * 1461 * Input: 1462 * o ie: the event connected to this interrupt. 1463 * o frame: some archs (i.e. i386) pass a frame to some. 1464 * handlers as their main argument. 1465 * Return value: 1466 * o 0: everything ok. 1467 * o EINVAL: stray interrupt. 1468 */ 1469 int 1470 intr_event_handle(struct intr_event *ie, struct trapframe *frame) 1471 { 1472 struct intr_handler *ih; 1473 struct trapframe *oldframe; 1474 struct thread *td; 1475 int error, ret, thread; 1476 1477 td = curthread; 1478 1479 #ifdef KSTACK_USAGE_PROF 1480 intr_prof_stack_use(td, frame); 1481 #endif 1482 1483 /* An interrupt with no event or handlers is a stray interrupt. */ 1484 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers)) 1485 return (EINVAL); 1486 1487 /* 1488 * Execute fast interrupt handlers directly. 1489 * To support clock handlers, if a handler registers 1490 * with a NULL argument, then we pass it a pointer to 1491 * a trapframe as its argument. 1492 */ 1493 td->td_intr_nesting_level++; 1494 thread = 0; 1495 ret = 0; 1496 critical_enter(); 1497 oldframe = td->td_intr_frame; 1498 td->td_intr_frame = frame; 1499 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 1500 if (ih->ih_filter == NULL) { 1501 thread = 1; 1502 continue; 1503 } 1504 CTR4(KTR_INTR, "%s: exec %p(%p) for %s", __func__, 1505 ih->ih_filter, ih->ih_argument == NULL ? frame : 1506 ih->ih_argument, ih->ih_name); 1507 if (ih->ih_argument == NULL) 1508 ret = ih->ih_filter(frame); 1509 else 1510 ret = ih->ih_filter(ih->ih_argument); 1511 KASSERT(ret == FILTER_STRAY || 1512 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 && 1513 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0), 1514 ("%s: incorrect return value %#x from %s", __func__, ret, 1515 ih->ih_name)); 1516 1517 /* 1518 * Wrapper handler special handling: 1519 * 1520 * in some particular cases (like pccard and pccbb), 1521 * the _real_ device handler is wrapped in a couple of 1522 * functions - a filter wrapper and an ithread wrapper. 1523 * In this case (and just in this case), the filter wrapper 1524 * could ask the system to schedule the ithread and mask 1525 * the interrupt source if the wrapped handler is composed 1526 * of just an ithread handler. 1527 * 1528 * TODO: write a generic wrapper to avoid people rolling 1529 * their own 1530 */ 1531 if (!thread) { 1532 if (ret == FILTER_SCHEDULE_THREAD) 1533 thread = 1; 1534 } 1535 } 1536 td->td_intr_frame = oldframe; 1537 1538 if (thread) { 1539 if (ie->ie_pre_ithread != NULL) 1540 ie->ie_pre_ithread(ie->ie_source); 1541 } else { 1542 if (ie->ie_post_filter != NULL) 1543 ie->ie_post_filter(ie->ie_source); 1544 } 1545 1546 /* Schedule the ithread if needed. */ 1547 if (thread) { 1548 error = intr_event_schedule_thread(ie); 1549 KASSERT(error == 0, ("bad stray interrupt")); 1550 } 1551 critical_exit(); 1552 td->td_intr_nesting_level--; 1553 return (0); 1554 } 1555 #else 1556 /* 1557 * This is the main code for interrupt threads. 1558 */ 1559 static void 1560 ithread_loop(void *arg) 1561 { 1562 struct intr_thread *ithd; 1563 struct intr_handler *ih; 1564 struct intr_event *ie; 1565 struct thread *td; 1566 struct proc *p; 1567 int priv; 1568 int wake; 1569 1570 td = curthread; 1571 p = td->td_proc; 1572 ih = (struct intr_handler *)arg; 1573 priv = (ih->ih_thread != NULL) ? 1 : 0; 1574 ithd = (priv) ? ih->ih_thread : ih->ih_event->ie_thread; 1575 KASSERT(ithd->it_thread == td, 1576 ("%s: ithread and proc linkage out of sync", __func__)); 1577 ie = ithd->it_event; 1578 ie->ie_count = 0; 1579 wake = 0; 1580 1581 /* 1582 * As long as we have interrupts outstanding, go through the 1583 * list of handlers, giving each one a go at it. 1584 */ 1585 for (;;) { 1586 /* 1587 * If we are an orphaned thread, then just die. 1588 */ 1589 if (ithd->it_flags & IT_DEAD) { 1590 CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__, 1591 p->p_pid, td->td_name); 1592 free(ithd, M_ITHREAD); 1593 kthread_exit(); 1594 } 1595 1596 /* 1597 * Service interrupts. If another interrupt arrives while 1598 * we are running, it will set it_need to note that we 1599 * should make another pass. 1600 * 1601 * The load_acq part of the following cmpset ensures 1602 * that the load of ih_need in ithread_execute_handlers() 1603 * is ordered after the load of it_need here. 1604 */ 1605 while (atomic_cmpset_acq_int(&ithd->it_need, 1, 0) != 0) { 1606 if (priv) 1607 priv_ithread_execute_handler(p, ih); 1608 else 1609 ithread_execute_handlers(p, ie); 1610 } 1611 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); 1612 mtx_assert(&Giant, MA_NOTOWNED); 1613 1614 /* 1615 * Processed all our interrupts. Now get the sched 1616 * lock. This may take a while and it_need may get 1617 * set again, so we have to check it again. 1618 */ 1619 thread_lock(td); 1620 if (atomic_load_acq_int(&ithd->it_need) == 0 && 1621 (ithd->it_flags & (IT_DEAD | IT_WAIT)) == 0) { 1622 TD_SET_IWAIT(td); 1623 ie->ie_count = 0; 1624 mi_switch(SW_VOL | SWT_IWAIT, NULL); 1625 } 1626 if (ithd->it_flags & IT_WAIT) { 1627 wake = 1; 1628 ithd->it_flags &= ~IT_WAIT; 1629 } 1630 thread_unlock(td); 1631 if (wake) { 1632 wakeup(ithd); 1633 wake = 0; 1634 } 1635 } 1636 } 1637 1638 /* 1639 * Main loop for interrupt filter. 1640 * 1641 * Some architectures (i386, amd64 and arm) require the optional frame 1642 * parameter, and use it as the main argument for fast handler execution 1643 * when ih_argument == NULL. 1644 * 1645 * Return value: 1646 * o FILTER_STRAY: No filter recognized the event, and no 1647 * filter-less handler is registered on this 1648 * line. 1649 * o FILTER_HANDLED: A filter claimed the event and served it. 1650 * o FILTER_SCHEDULE_THREAD: No filter claimed the event, but there's at 1651 * least one filter-less handler on this line. 1652 * o FILTER_HANDLED | 1653 * FILTER_SCHEDULE_THREAD: A filter claimed the event, and asked for 1654 * scheduling the per-handler ithread. 1655 * 1656 * In case an ithread has to be scheduled, in *ithd there will be a 1657 * pointer to a struct intr_thread containing the thread to be 1658 * scheduled. 1659 */ 1660 1661 static int 1662 intr_filter_loop(struct intr_event *ie, struct trapframe *frame, 1663 struct intr_thread **ithd) 1664 { 1665 struct intr_handler *ih; 1666 void *arg; 1667 int ret, thread_only; 1668 1669 ret = 0; 1670 thread_only = 0; 1671 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) { 1672 /* 1673 * Execute fast interrupt handlers directly. 1674 * To support clock handlers, if a handler registers 1675 * with a NULL argument, then we pass it a pointer to 1676 * a trapframe as its argument. 1677 */ 1678 arg = ((ih->ih_argument == NULL) ? frame : ih->ih_argument); 1679 1680 CTR5(KTR_INTR, "%s: exec %p/%p(%p) for %s", __func__, 1681 ih->ih_filter, ih->ih_handler, arg, ih->ih_name); 1682 1683 if (ih->ih_filter != NULL) 1684 ret = ih->ih_filter(arg); 1685 else { 1686 thread_only = 1; 1687 continue; 1688 } 1689 KASSERT(ret == FILTER_STRAY || 1690 ((ret & (FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) != 0 && 1691 (ret & ~(FILTER_SCHEDULE_THREAD | FILTER_HANDLED)) == 0), 1692 ("%s: incorrect return value %#x from %s", __func__, ret, 1693 ih->ih_name)); 1694 if (ret & FILTER_STRAY) 1695 continue; 1696 else { 1697 *ithd = ih->ih_thread; 1698 return (ret); 1699 } 1700 } 1701 1702 /* 1703 * No filters handled the interrupt and we have at least 1704 * one handler without a filter. In this case, we schedule 1705 * all of the filter-less handlers to run in the ithread. 1706 */ 1707 if (thread_only) { 1708 *ithd = ie->ie_thread; 1709 return (FILTER_SCHEDULE_THREAD); 1710 } 1711 return (FILTER_STRAY); 1712 } 1713 1714 /* 1715 * Main interrupt handling body. 1716 * 1717 * Input: 1718 * o ie: the event connected to this interrupt. 1719 * o frame: some archs (i.e. i386) pass a frame to some. 1720 * handlers as their main argument. 1721 * Return value: 1722 * o 0: everything ok. 1723 * o EINVAL: stray interrupt. 1724 */ 1725 int 1726 intr_event_handle(struct intr_event *ie, struct trapframe *frame) 1727 { 1728 struct intr_thread *ithd; 1729 struct trapframe *oldframe; 1730 struct thread *td; 1731 int thread; 1732 1733 ithd = NULL; 1734 td = curthread; 1735 1736 if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers)) 1737 return (EINVAL); 1738 1739 td->td_intr_nesting_level++; 1740 thread = 0; 1741 critical_enter(); 1742 oldframe = td->td_intr_frame; 1743 td->td_intr_frame = frame; 1744 thread = intr_filter_loop(ie, frame, &ithd); 1745 if (thread & FILTER_HANDLED) { 1746 if (ie->ie_post_filter != NULL) 1747 ie->ie_post_filter(ie->ie_source); 1748 } else { 1749 if (ie->ie_pre_ithread != NULL) 1750 ie->ie_pre_ithread(ie->ie_source); 1751 } 1752 td->td_intr_frame = oldframe; 1753 critical_exit(); 1754 1755 /* Interrupt storm logic */ 1756 if (thread & FILTER_STRAY) { 1757 ie->ie_count++; 1758 if (ie->ie_count < intr_storm_threshold) 1759 printf("Interrupt stray detection not present\n"); 1760 } 1761 1762 /* Schedule an ithread if needed. */ 1763 if (thread & FILTER_SCHEDULE_THREAD) { 1764 if (intr_event_schedule_thread(ie, ithd) != 0) 1765 panic("%s: impossible stray interrupt", __func__); 1766 } 1767 td->td_intr_nesting_level--; 1768 return (0); 1769 } 1770 #endif 1771 1772 #ifdef DDB 1773 /* 1774 * Dump details about an interrupt handler 1775 */ 1776 static void 1777 db_dump_intrhand(struct intr_handler *ih) 1778 { 1779 int comma; 1780 1781 db_printf("\t%-10s ", ih->ih_name); 1782 switch (ih->ih_pri) { 1783 case PI_REALTIME: 1784 db_printf("CLK "); 1785 break; 1786 case PI_AV: 1787 db_printf("AV "); 1788 break; 1789 case PI_TTY: 1790 db_printf("TTY "); 1791 break; 1792 case PI_NET: 1793 db_printf("NET "); 1794 break; 1795 case PI_DISK: 1796 db_printf("DISK"); 1797 break; 1798 case PI_DULL: 1799 db_printf("DULL"); 1800 break; 1801 default: 1802 if (ih->ih_pri >= PI_SOFT) 1803 db_printf("SWI "); 1804 else 1805 db_printf("%4u", ih->ih_pri); 1806 break; 1807 } 1808 db_printf(" "); 1809 if (ih->ih_filter != NULL) { 1810 db_printf("[F]"); 1811 db_printsym((uintptr_t)ih->ih_filter, DB_STGY_PROC); 1812 } 1813 if (ih->ih_handler != NULL) { 1814 if (ih->ih_filter != NULL) 1815 db_printf(","); 1816 db_printf("[H]"); 1817 db_printsym((uintptr_t)ih->ih_handler, DB_STGY_PROC); 1818 } 1819 db_printf("(%p)", ih->ih_argument); 1820 if (ih->ih_need || 1821 (ih->ih_flags & (IH_EXCLUSIVE | IH_ENTROPY | IH_DEAD | 1822 IH_MPSAFE)) != 0) { 1823 db_printf(" {"); 1824 comma = 0; 1825 if (ih->ih_flags & IH_EXCLUSIVE) { 1826 if (comma) 1827 db_printf(", "); 1828 db_printf("EXCL"); 1829 comma = 1; 1830 } 1831 if (ih->ih_flags & IH_ENTROPY) { 1832 if (comma) 1833 db_printf(", "); 1834 db_printf("ENTROPY"); 1835 comma = 1; 1836 } 1837 if (ih->ih_flags & IH_DEAD) { 1838 if (comma) 1839 db_printf(", "); 1840 db_printf("DEAD"); 1841 comma = 1; 1842 } 1843 if (ih->ih_flags & IH_MPSAFE) { 1844 if (comma) 1845 db_printf(", "); 1846 db_printf("MPSAFE"); 1847 comma = 1; 1848 } 1849 if (ih->ih_need) { 1850 if (comma) 1851 db_printf(", "); 1852 db_printf("NEED"); 1853 } 1854 db_printf("}"); 1855 } 1856 db_printf("\n"); 1857 } 1858 1859 /* 1860 * Dump details about a event. 1861 */ 1862 void 1863 db_dump_intr_event(struct intr_event *ie, int handlers) 1864 { 1865 struct intr_handler *ih; 1866 struct intr_thread *it; 1867 int comma; 1868 1869 db_printf("%s ", ie->ie_fullname); 1870 it = ie->ie_thread; 1871 if (it != NULL) 1872 db_printf("(pid %d)", it->it_thread->td_proc->p_pid); 1873 else 1874 db_printf("(no thread)"); 1875 if ((ie->ie_flags & (IE_SOFT | IE_ENTROPY | IE_ADDING_THREAD)) != 0 || 1876 (it != NULL && it->it_need)) { 1877 db_printf(" {"); 1878 comma = 0; 1879 if (ie->ie_flags & IE_SOFT) { 1880 db_printf("SOFT"); 1881 comma = 1; 1882 } 1883 if (ie->ie_flags & IE_ENTROPY) { 1884 if (comma) 1885 db_printf(", "); 1886 db_printf("ENTROPY"); 1887 comma = 1; 1888 } 1889 if (ie->ie_flags & IE_ADDING_THREAD) { 1890 if (comma) 1891 db_printf(", "); 1892 db_printf("ADDING_THREAD"); 1893 comma = 1; 1894 } 1895 if (it != NULL && it->it_need) { 1896 if (comma) 1897 db_printf(", "); 1898 db_printf("NEED"); 1899 } 1900 db_printf("}"); 1901 } 1902 db_printf("\n"); 1903 1904 if (handlers) 1905 TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) 1906 db_dump_intrhand(ih); 1907 } 1908 1909 /* 1910 * Dump data about interrupt handlers 1911 */ 1912 DB_SHOW_COMMAND(intr, db_show_intr) 1913 { 1914 struct intr_event *ie; 1915 int all, verbose; 1916 1917 verbose = strchr(modif, 'v') != NULL; 1918 all = strchr(modif, 'a') != NULL; 1919 TAILQ_FOREACH(ie, &event_list, ie_list) { 1920 if (!all && TAILQ_EMPTY(&ie->ie_handlers)) 1921 continue; 1922 db_dump_intr_event(ie, verbose); 1923 if (db_pager_quit) 1924 break; 1925 } 1926 } 1927 #endif /* DDB */ 1928 1929 /* 1930 * Start standard software interrupt threads 1931 */ 1932 static void 1933 start_softintr(void *dummy) 1934 { 1935 1936 if (swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, INTR_MPSAFE, &vm_ih)) 1937 panic("died while creating vm swi ithread"); 1938 } 1939 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr, 1940 NULL); 1941 1942 /* 1943 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 1944 * The data for this machine dependent, and the declarations are in machine 1945 * dependent code. The layout of intrnames and intrcnt however is machine 1946 * independent. 1947 * 1948 * We do not know the length of intrcnt and intrnames at compile time, so 1949 * calculate things at run time. 1950 */ 1951 static int 1952 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 1953 { 1954 return (sysctl_handle_opaque(oidp, intrnames, sintrnames, req)); 1955 } 1956 1957 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 1958 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 1959 1960 static int 1961 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 1962 { 1963 #ifdef SCTL_MASK32 1964 uint32_t *intrcnt32; 1965 unsigned i; 1966 int error; 1967 1968 if (req->flags & SCTL_MASK32) { 1969 if (!req->oldptr) 1970 return (sysctl_handle_opaque(oidp, NULL, sintrcnt / 2, req)); 1971 intrcnt32 = malloc(sintrcnt / 2, M_TEMP, M_NOWAIT); 1972 if (intrcnt32 == NULL) 1973 return (ENOMEM); 1974 for (i = 0; i < sintrcnt / sizeof (u_long); i++) 1975 intrcnt32[i] = intrcnt[i]; 1976 error = sysctl_handle_opaque(oidp, intrcnt32, sintrcnt / 2, req); 1977 free(intrcnt32, M_TEMP); 1978 return (error); 1979 } 1980 #endif 1981 return (sysctl_handle_opaque(oidp, intrcnt, sintrcnt, req)); 1982 } 1983 1984 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 1985 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 1986 1987 #ifdef DDB 1988 /* 1989 * DDB command to dump the interrupt statistics. 1990 */ 1991 DB_SHOW_COMMAND(intrcnt, db_show_intrcnt) 1992 { 1993 u_long *i; 1994 char *cp; 1995 u_int j; 1996 1997 cp = intrnames; 1998 j = 0; 1999 for (i = intrcnt; j < (sintrcnt / sizeof(u_long)) && !db_pager_quit; 2000 i++, j++) { 2001 if (*cp == '\0') 2002 break; 2003 if (*i != 0) 2004 db_printf("%s\t%lu\n", cp, *i); 2005 cp += strlen(cp) + 1; 2006 } 2007 } 2008 #endif
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