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 * $FreeBSD$ 27 * 28 */ 29 30 31 #include <sys/param.h> 32 #include <sys/bus.h> 33 #include <sys/conf.h> 34 #include <sys/rtprio.h> 35 #include <sys/systm.h> 36 #include <sys/interrupt.h> 37 #include <sys/kernel.h> 38 #include <sys/kthread.h> 39 #include <sys/ktr.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.h> 42 #include <sys/mutex.h> 43 #include <sys/proc.h> 44 #include <sys/random.h> 45 #include <sys/resourcevar.h> 46 #include <sys/sysctl.h> 47 #include <sys/unistd.h> 48 #include <sys/vmmeter.h> 49 #include <machine/atomic.h> 50 #include <machine/cpu.h> 51 #include <machine/md_var.h> 52 #include <machine/stdarg.h> 53 54 struct int_entropy { 55 struct proc *proc; 56 int vector; 57 }; 58 59 void *vm_ih; 60 void *softclock_ih; 61 struct ithd *clk_ithd; 62 struct ithd *tty_ithd; 63 64 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads"); 65 66 static void ithread_update(struct ithd *); 67 static void ithread_loop(void *); 68 static void start_softintr(void *); 69 70 u_char 71 ithread_priority(enum intr_type flags) 72 { 73 u_char pri; 74 75 flags &= (INTR_TYPE_TTY | INTR_TYPE_BIO | INTR_TYPE_NET | 76 INTR_TYPE_CAM | INTR_TYPE_MISC | INTR_TYPE_CLK | INTR_TYPE_AV); 77 switch (flags) { 78 case INTR_TYPE_TTY: 79 pri = PI_TTYLOW; 80 break; 81 case INTR_TYPE_BIO: 82 /* 83 * XXX We need to refine this. BSD/OS distinguishes 84 * between tape and disk priorities. 85 */ 86 pri = PI_DISK; 87 break; 88 case INTR_TYPE_NET: 89 pri = PI_NET; 90 break; 91 case INTR_TYPE_CAM: 92 pri = PI_DISK; /* XXX or PI_CAM? */ 93 break; 94 case INTR_TYPE_AV: /* Audio/video */ 95 pri = PI_AV; 96 break; 97 case INTR_TYPE_CLK: 98 pri = PI_REALTIME; 99 break; 100 case INTR_TYPE_MISC: 101 pri = PI_DULL; /* don't care */ 102 break; 103 default: 104 /* We didn't specify an interrupt level. */ 105 panic("ithread_priority: no interrupt type in flags"); 106 } 107 108 return pri; 109 } 110 111 /* 112 * Regenerate the name (p_comm) and priority for a threaded interrupt thread. 113 */ 114 static void 115 ithread_update(struct ithd *ithd) 116 { 117 struct intrhand *ih; 118 struct thread *td; 119 struct proc *p; 120 int entropy; 121 122 mtx_assert(&ithd->it_lock, MA_OWNED); 123 td = ithd->it_td; 124 if (td == NULL) 125 return; 126 p = td->td_proc; 127 128 strlcpy(p->p_comm, ithd->it_name, sizeof(p->p_comm)); 129 130 ih = TAILQ_FIRST(&ithd->it_handlers); 131 if (ih == NULL) { 132 mtx_lock_spin(&sched_lock); 133 td->td_priority = PRI_MAX_ITHD; 134 td->td_base_pri = PRI_MAX_ITHD; 135 mtx_unlock_spin(&sched_lock); 136 ithd->it_flags &= ~IT_ENTROPY; 137 return; 138 } 139 entropy = 0; 140 mtx_lock_spin(&sched_lock); 141 td->td_priority = ih->ih_pri; 142 td->td_base_pri = ih->ih_pri; 143 mtx_unlock_spin(&sched_lock); 144 TAILQ_FOREACH(ih, &ithd->it_handlers, ih_next) { 145 if (strlen(p->p_comm) + strlen(ih->ih_name) + 1 < 146 sizeof(p->p_comm)) { 147 strcat(p->p_comm, " "); 148 strcat(p->p_comm, ih->ih_name); 149 } else if (strlen(p->p_comm) + 1 == sizeof(p->p_comm)) { 150 if (p->p_comm[sizeof(p->p_comm) - 2] == '+') 151 p->p_comm[sizeof(p->p_comm) - 2] = '*'; 152 else 153 p->p_comm[sizeof(p->p_comm) - 2] = '+'; 154 } else 155 strcat(p->p_comm, "+"); 156 if (ih->ih_flags & IH_ENTROPY) 157 entropy++; 158 } 159 if (entropy) 160 ithd->it_flags |= IT_ENTROPY; 161 else 162 ithd->it_flags &= ~IT_ENTROPY; 163 CTR2(KTR_INTR, "%s: updated %s", __func__, p->p_comm); 164 } 165 166 int 167 ithread_create(struct ithd **ithread, int vector, int flags, 168 void (*disable)(int), void (*enable)(int), const char *fmt, ...) 169 { 170 struct ithd *ithd; 171 struct thread *td; 172 struct proc *p; 173 int error; 174 va_list ap; 175 176 /* The only valid flag during creation is IT_SOFT. */ 177 if ((flags & ~IT_SOFT) != 0) 178 return (EINVAL); 179 180 ithd = malloc(sizeof(struct ithd), M_ITHREAD, M_WAITOK | M_ZERO); 181 ithd->it_vector = vector; 182 ithd->it_disable = disable; 183 ithd->it_enable = enable; 184 ithd->it_flags = flags; 185 TAILQ_INIT(&ithd->it_handlers); 186 mtx_init(&ithd->it_lock, "ithread", NULL, MTX_DEF); 187 188 va_start(ap, fmt); 189 vsnprintf(ithd->it_name, sizeof(ithd->it_name), fmt, ap); 190 va_end(ap); 191 192 error = kthread_create(ithread_loop, ithd, &p, RFSTOPPED | RFHIGHPID, 193 0, "%s", ithd->it_name); 194 if (error) { 195 mtx_destroy(&ithd->it_lock); 196 free(ithd, M_ITHREAD); 197 return (error); 198 } 199 td = FIRST_THREAD_IN_PROC(p); /* XXXKSE */ 200 mtx_lock_spin(&sched_lock); 201 td->td_ksegrp->kg_pri_class = PRI_ITHD; 202 td->td_priority = PRI_MAX_ITHD; 203 TD_SET_IWAIT(td); 204 mtx_unlock_spin(&sched_lock); 205 ithd->it_td = td; 206 td->td_ithd = ithd; 207 if (ithread != NULL) 208 *ithread = ithd; 209 CTR2(KTR_INTR, "%s: created %s", __func__, ithd->it_name); 210 return (0); 211 } 212 213 int 214 ithread_destroy(struct ithd *ithread) 215 { 216 217 struct thread *td; 218 if (ithread == NULL) 219 return (EINVAL); 220 221 td = ithread->it_td; 222 mtx_lock(&ithread->it_lock); 223 if (!TAILQ_EMPTY(&ithread->it_handlers)) { 224 mtx_unlock(&ithread->it_lock); 225 return (EINVAL); 226 } 227 ithread->it_flags |= IT_DEAD; 228 mtx_lock_spin(&sched_lock); 229 if (TD_AWAITING_INTR(td)) { 230 TD_CLR_IWAIT(td); 231 setrunqueue(td); 232 } 233 mtx_unlock_spin(&sched_lock); 234 mtx_unlock(&ithread->it_lock); 235 CTR2(KTR_INTR, "%s: killing %s", __func__, ithread->it_name); 236 return (0); 237 } 238 239 int 240 ithread_add_handler(struct ithd* ithread, const char *name, 241 driver_intr_t handler, void *arg, u_char pri, enum intr_type flags, 242 void **cookiep) 243 { 244 struct intrhand *ih, *temp_ih; 245 246 if (ithread == NULL || name == NULL || handler == NULL) 247 return (EINVAL); 248 if ((flags & INTR_FAST) !=0) 249 flags |= INTR_EXCL; 250 251 ih = malloc(sizeof(struct intrhand), M_ITHREAD, M_WAITOK | M_ZERO); 252 ih->ih_handler = handler; 253 ih->ih_argument = arg; 254 ih->ih_name = name; 255 ih->ih_ithread = ithread; 256 ih->ih_pri = pri; 257 if (flags & INTR_FAST) 258 ih->ih_flags = IH_FAST | IH_EXCLUSIVE; 259 else if (flags & INTR_EXCL) 260 ih->ih_flags = IH_EXCLUSIVE; 261 if (flags & INTR_MPSAFE) 262 ih->ih_flags |= IH_MPSAFE; 263 if (flags & INTR_ENTROPY) 264 ih->ih_flags |= IH_ENTROPY; 265 266 mtx_lock(&ithread->it_lock); 267 if ((flags & INTR_EXCL) !=0 && !TAILQ_EMPTY(&ithread->it_handlers)) 268 goto fail; 269 if (!TAILQ_EMPTY(&ithread->it_handlers) && 270 (TAILQ_FIRST(&ithread->it_handlers)->ih_flags & IH_EXCLUSIVE) != 0) 271 goto fail; 272 273 TAILQ_FOREACH(temp_ih, &ithread->it_handlers, ih_next) 274 if (temp_ih->ih_pri > ih->ih_pri) 275 break; 276 if (temp_ih == NULL) 277 TAILQ_INSERT_TAIL(&ithread->it_handlers, ih, ih_next); 278 else 279 TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); 280 ithread_update(ithread); 281 mtx_unlock(&ithread->it_lock); 282 283 if (cookiep != NULL) 284 *cookiep = ih; 285 CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, 286 ithread->it_name); 287 return (0); 288 289 fail: 290 mtx_unlock(&ithread->it_lock); 291 free(ih, M_ITHREAD); 292 return (EINVAL); 293 } 294 295 int 296 ithread_remove_handler(void *cookie) 297 { 298 struct intrhand *handler = (struct intrhand *)cookie; 299 struct ithd *ithread; 300 #ifdef INVARIANTS 301 struct intrhand *ih; 302 #endif 303 304 if (handler == NULL) 305 return (EINVAL); 306 ithread = handler->ih_ithread; 307 KASSERT(ithread != NULL, 308 ("interrupt handler \"%s\" has a NULL interrupt thread", 309 handler->ih_name)); 310 CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name, 311 ithread->it_name); 312 mtx_lock(&ithread->it_lock); 313 #ifdef INVARIANTS 314 TAILQ_FOREACH(ih, &ithread->it_handlers, ih_next) 315 if (ih == handler) 316 goto ok; 317 mtx_unlock(&ithread->it_lock); 318 panic("interrupt handler \"%s\" not found in interrupt thread \"%s\"", 319 ih->ih_name, ithread->it_name); 320 ok: 321 #endif 322 /* 323 * If the interrupt thread is already running, then just mark this 324 * handler as being dead and let the ithread do the actual removal. 325 */ 326 mtx_lock_spin(&sched_lock); 327 if (!TD_AWAITING_INTR(ithread->it_td)) { 328 handler->ih_flags |= IH_DEAD; 329 330 /* 331 * Ensure that the thread will process the handler list 332 * again and remove this handler if it has already passed 333 * it on the list. 334 */ 335 ithread->it_need = 1; 336 } else 337 TAILQ_REMOVE(&ithread->it_handlers, handler, ih_next); 338 mtx_unlock_spin(&sched_lock); 339 if ((handler->ih_flags & IH_DEAD) != 0) 340 msleep(handler, &ithread->it_lock, PUSER, "itrmh", 0); 341 ithread_update(ithread); 342 mtx_unlock(&ithread->it_lock); 343 free(handler, M_ITHREAD); 344 return (0); 345 } 346 347 int 348 ithread_schedule(struct ithd *ithread, int do_switch) 349 { 350 struct int_entropy entropy; 351 struct thread *td; 352 struct thread *ctd; 353 struct proc *p; 354 355 /* 356 * If no ithread or no handlers, then we have a stray interrupt. 357 */ 358 if ((ithread == NULL) || TAILQ_EMPTY(&ithread->it_handlers)) 359 return (EINVAL); 360 361 ctd = curthread; 362 /* 363 * If any of the handlers for this ithread claim to be good 364 * sources of entropy, then gather some. 365 */ 366 if (harvest.interrupt && ithread->it_flags & IT_ENTROPY) { 367 entropy.vector = ithread->it_vector; 368 entropy.proc = ctd->td_proc; 369 random_harvest(&entropy, sizeof(entropy), 2, 0, 370 RANDOM_INTERRUPT); 371 } 372 373 td = ithread->it_td; 374 p = td->td_proc; 375 KASSERT(p != NULL, ("ithread %s has no process", ithread->it_name)); 376 CTR4(KTR_INTR, "%s: pid %d: (%s) need = %d", 377 __func__, p->p_pid, p->p_comm, ithread->it_need); 378 379 /* 380 * Set it_need to tell the thread to keep running if it is already 381 * running. Then, grab sched_lock and see if we actually need to 382 * put this thread on the runqueue. If so and the do_switch flag is 383 * true and it is safe to switch, then switch to the ithread 384 * immediately. Otherwise, set the needresched flag to guarantee 385 * that this ithread will run before any userland processes. 386 */ 387 ithread->it_need = 1; 388 mtx_lock_spin(&sched_lock); 389 if (TD_AWAITING_INTR(td)) { 390 CTR2(KTR_INTR, "%s: setrunqueue %d", __func__, p->p_pid); 391 TD_CLR_IWAIT(td); 392 setrunqueue(td); 393 if (do_switch && 394 (ctd->td_critnest == 1) ) { 395 KASSERT((TD_IS_RUNNING(ctd)), 396 ("ithread_schedule: Bad state for curthread.")); 397 ctd->td_proc->p_stats->p_ru.ru_nivcsw++; 398 if (ctd->td_flags & TDF_IDLETD) 399 ctd->td_state = TDS_CAN_RUN; /* XXXKSE */ 400 mi_switch(); 401 } else { 402 curthread->td_flags |= TDF_NEEDRESCHED; 403 } 404 } else { 405 CTR4(KTR_INTR, "%s: pid %d: it_need %d, state %d", 406 __func__, p->p_pid, ithread->it_need, td->td_state); 407 } 408 mtx_unlock_spin(&sched_lock); 409 410 return (0); 411 } 412 413 int 414 swi_add(struct ithd **ithdp, const char *name, driver_intr_t handler, 415 void *arg, int pri, enum intr_type flags, void **cookiep) 416 { 417 struct ithd *ithd; 418 int error; 419 420 if (flags & (INTR_FAST | INTR_ENTROPY)) 421 return (EINVAL); 422 423 ithd = (ithdp != NULL) ? *ithdp : NULL; 424 425 if (ithd != NULL) { 426 if ((ithd->it_flags & IT_SOFT) == 0) 427 return(EINVAL); 428 } else { 429 error = ithread_create(&ithd, pri, IT_SOFT, NULL, NULL, 430 "swi%d:", pri); 431 if (error) 432 return (error); 433 434 if (ithdp != NULL) 435 *ithdp = ithd; 436 } 437 return (ithread_add_handler(ithd, name, handler, arg, 438 (pri * RQ_PPQ) + PI_SOFT, flags, cookiep)); 439 } 440 441 442 /* 443 * Schedule a heavyweight software interrupt process. 444 */ 445 void 446 swi_sched(void *cookie, int flags) 447 { 448 struct intrhand *ih = (struct intrhand *)cookie; 449 struct ithd *it = ih->ih_ithread; 450 int error; 451 452 atomic_add_int(&cnt.v_intr, 1); /* one more global interrupt */ 453 454 CTR3(KTR_INTR, "swi_sched pid %d(%s) need=%d", 455 it->it_td->td_proc->p_pid, it->it_td->td_proc->p_comm, it->it_need); 456 457 /* 458 * Set ih_need for this handler so that if the ithread is already 459 * running it will execute this handler on the next pass. Otherwise, 460 * it will execute it the next time it runs. 461 */ 462 atomic_store_rel_int(&ih->ih_need, 1); 463 if (!(flags & SWI_DELAY)) { 464 error = ithread_schedule(it, !cold && !dumping); 465 KASSERT(error == 0, ("stray software interrupt")); 466 } 467 } 468 469 /* 470 * This is the main code for interrupt threads. 471 */ 472 static void 473 ithread_loop(void *arg) 474 { 475 struct ithd *ithd; /* our thread context */ 476 struct intrhand *ih; /* and our interrupt handler chain */ 477 struct thread *td; 478 struct proc *p; 479 480 td = curthread; 481 p = td->td_proc; 482 ithd = (struct ithd *)arg; /* point to myself */ 483 KASSERT(ithd->it_td == td && td->td_ithd == ithd, 484 ("%s: ithread and proc linkage out of sync", __func__)); 485 486 /* 487 * As long as we have interrupts outstanding, go through the 488 * list of handlers, giving each one a go at it. 489 */ 490 for (;;) { 491 /* 492 * If we are an orphaned thread, then just die. 493 */ 494 if (ithd->it_flags & IT_DEAD) { 495 CTR3(KTR_INTR, "%s: pid %d: (%s) exiting", __func__, 496 p->p_pid, p->p_comm); 497 td->td_ithd = NULL; 498 mtx_destroy(&ithd->it_lock); 499 mtx_lock(&Giant); 500 free(ithd, M_ITHREAD); 501 kthread_exit(0); 502 } 503 504 CTR4(KTR_INTR, "%s: pid %d: (%s) need=%d", __func__, 505 p->p_pid, p->p_comm, ithd->it_need); 506 while (ithd->it_need) { 507 /* 508 * Service interrupts. If another interrupt 509 * arrives while we are running, they will set 510 * it_need to denote that we should make 511 * another pass. 512 */ 513 atomic_store_rel_int(&ithd->it_need, 0); 514 restart: 515 TAILQ_FOREACH(ih, &ithd->it_handlers, ih_next) { 516 if (ithd->it_flags & IT_SOFT && !ih->ih_need) 517 continue; 518 atomic_store_rel_int(&ih->ih_need, 0); 519 CTR6(KTR_INTR, 520 "%s: pid %d ih=%p: %p(%p) flg=%x", __func__, 521 p->p_pid, (void *)ih, 522 (void *)ih->ih_handler, ih->ih_argument, 523 ih->ih_flags); 524 525 if ((ih->ih_flags & IH_DEAD) != 0) { 526 mtx_lock(&ithd->it_lock); 527 TAILQ_REMOVE(&ithd->it_handlers, ih, 528 ih_next); 529 wakeup(ih); 530 mtx_unlock(&ithd->it_lock); 531 goto restart; 532 } 533 if ((ih->ih_flags & IH_MPSAFE) == 0) 534 mtx_lock(&Giant); 535 ih->ih_handler(ih->ih_argument); 536 if ((ih->ih_flags & IH_MPSAFE) == 0) 537 mtx_unlock(&Giant); 538 } 539 } 540 541 /* 542 * Processed all our interrupts. Now get the sched 543 * lock. This may take a while and it_need may get 544 * set again, so we have to check it again. 545 */ 546 WITNESS_WARN(WARN_PANIC, NULL, "suspending ithread"); 547 mtx_assert(&Giant, MA_NOTOWNED); 548 mtx_lock_spin(&sched_lock); 549 if (!ithd->it_need) { 550 /* 551 * Should we call this earlier in the loop above? 552 */ 553 if (ithd->it_enable != NULL) 554 ithd->it_enable(ithd->it_vector); 555 TD_SET_IWAIT(td); /* we're idle */ 556 p->p_stats->p_ru.ru_nvcsw++; 557 CTR2(KTR_INTR, "%s: pid %d: done", __func__, p->p_pid); 558 mi_switch(); 559 CTR2(KTR_INTR, "%s: pid %d: resumed", __func__, p->p_pid); 560 } 561 mtx_unlock_spin(&sched_lock); 562 } 563 } 564 565 /* 566 * Start standard software interrupt threads 567 */ 568 static void 569 start_softintr(void *dummy) 570 { 571 struct proc *p; 572 573 if (swi_add(&clk_ithd, "clock", softclock, NULL, SWI_CLOCK, 574 INTR_MPSAFE, &softclock_ih) || 575 swi_add(NULL, "vm", swi_vm, NULL, SWI_VM, 0, &vm_ih)) 576 panic("died while creating standard software ithreads"); 577 578 p = clk_ithd->it_td->td_proc; 579 PROC_LOCK(p); 580 p->p_flag |= P_NOLOAD; 581 PROC_UNLOCK(p); 582 } 583 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr, NULL) 584 585 /* 586 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 587 * The data for this machine dependent, and the declarations are in machine 588 * dependent code. The layout of intrnames and intrcnt however is machine 589 * independent. 590 * 591 * We do not know the length of intrcnt and intrnames at compile time, so 592 * calculate things at run time. 593 */ 594 static int 595 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 596 { 597 return (sysctl_handle_opaque(oidp, intrnames, eintrnames - intrnames, 598 req)); 599 } 600 601 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 602 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 603 604 static int 605 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 606 { 607 return (sysctl_handle_opaque(oidp, intrcnt, 608 (char *)eintrcnt - (char *)intrcnt, req)); 609 } 610 611 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 612 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 613