1 /* 2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved. 3 * Copyright (c) 1997, Stefan Esser <se@freebsd.org> 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: src/sys/kern/kern_intr.c,v 1.24.2.1 2001/10/14 20:05:50 luigi Exp $ 27 * $DragonFly: src/sys/kern/kern_intr.c,v 1.33 2005/11/04 08:17:19 dillon Exp $ 28 * 29 */ 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/malloc.h> 34 #include <sys/kernel.h> 35 #include <sys/sysctl.h> 36 #include <sys/thread.h> 37 #include <sys/proc.h> 38 #include <sys/thread2.h> 39 #include <sys/random.h> 40 #include <sys/serialize.h> 41 #include <sys/bus.h> 42 #include <sys/machintr.h> 43 44 #include <machine/ipl.h> 45 #include <machine/frame.h> 46 47 #include <sys/interrupt.h> 48 49 typedef struct intrec { 50 struct intrec *next; 51 inthand2_t *handler; 52 void *argument; 53 char *name; 54 int intr; 55 int intr_flags; 56 struct lwkt_serialize *serializer; 57 } *intrec_t; 58 59 struct intr_info { 60 intrec_t i_reclist; 61 struct thread i_thread; 62 struct random_softc i_random; 63 int i_running; 64 long i_count; 65 int i_fast; 66 int i_slow; 67 int i_state; 68 } intr_info_ary[MAX_INTS]; 69 70 int max_installed_hard_intr; 71 int max_installed_soft_intr; 72 73 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000 74 75 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS); 76 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS); 77 static void emergency_intr_timer_callback(systimer_t, struct intrframe *); 78 static void ithread_handler(void *arg); 79 static void ithread_emergency(void *arg); 80 81 int intr_info_size = sizeof(intr_info_ary) / sizeof(intr_info_ary[0]); 82 83 static struct systimer emergency_intr_timer; 84 static struct thread emergency_intr_thread; 85 86 #define ISTATE_NOTHREAD 0 87 #define ISTATE_NORMAL 1 88 #define ISTATE_LIVELOCKED 2 89 90 static int livelock_limit = 50000; 91 static int livelock_lowater = 20000; 92 SYSCTL_INT(_kern, OID_AUTO, livelock_limit, 93 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit"); 94 SYSCTL_INT(_kern, OID_AUTO, livelock_lowater, 95 CTLFLAG_RW, &livelock_lowater, 0, "Livelock low-water mark restore"); 96 97 static int emergency_intr_enable = 0; /* emergency interrupt polling */ 98 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable); 99 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_enable, CTLTYPE_INT | CTLFLAG_RW, 100 0, 0, sysctl_emergency_enable, "I", "Emergency Interrupt Poll Enable"); 101 102 static int emergency_intr_freq = 10; /* emergency polling frequency */ 103 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq); 104 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_freq, CTLTYPE_INT | CTLFLAG_RW, 105 0, 0, sysctl_emergency_freq, "I", "Emergency Interrupt Poll Frequency"); 106 107 /* 108 * Sysctl support routines 109 */ 110 static int 111 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS) 112 { 113 int error, enabled; 114 115 enabled = emergency_intr_enable; 116 error = sysctl_handle_int(oidp, &enabled, 0, req); 117 if (error || req->newptr == NULL) 118 return error; 119 emergency_intr_enable = enabled; 120 if (emergency_intr_enable) { 121 emergency_intr_timer.periodic = 122 sys_cputimer->fromhz(emergency_intr_freq); 123 } else { 124 emergency_intr_timer.periodic = sys_cputimer->fromhz(1); 125 } 126 return 0; 127 } 128 129 static int 130 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS) 131 { 132 int error, phz; 133 134 phz = emergency_intr_freq; 135 error = sysctl_handle_int(oidp, &phz, 0, req); 136 if (error || req->newptr == NULL) 137 return error; 138 if (phz <= 0) 139 return EINVAL; 140 else if (phz > EMERGENCY_INTR_POLLING_FREQ_MAX) 141 phz = EMERGENCY_INTR_POLLING_FREQ_MAX; 142 143 emergency_intr_freq = phz; 144 if (emergency_intr_enable) { 145 emergency_intr_timer.periodic = 146 sys_cputimer->fromhz(emergency_intr_freq); 147 } else { 148 emergency_intr_timer.periodic = sys_cputimer->fromhz(1); 149 } 150 return 0; 151 } 152 153 /* 154 * Register an SWI or INTerrupt handler. 155 */ 156 void * 157 register_swi(int intr, inthand2_t *handler, void *arg, const char *name, 158 struct lwkt_serialize *serializer) 159 { 160 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 161 panic("register_swi: bad intr %d", intr); 162 return(register_int(intr, handler, arg, name, serializer, 0)); 163 } 164 165 void * 166 register_int(int intr, inthand2_t *handler, void *arg, const char *name, 167 struct lwkt_serialize *serializer, int intr_flags) 168 { 169 struct intr_info *info; 170 struct intrec **list; 171 intrec_t rec; 172 173 if (intr < 0 || intr >= MAX_INTS) 174 panic("register_int: bad intr %d", intr); 175 if (name == NULL) 176 name = "???"; 177 info = &intr_info_ary[intr]; 178 179 rec = malloc(sizeof(struct intrec), M_DEVBUF, M_INTWAIT); 180 rec->name = malloc(strlen(name) + 1, M_DEVBUF, M_INTWAIT); 181 strcpy(rec->name, name); 182 183 rec->handler = handler; 184 rec->argument = arg; 185 rec->intr = intr; 186 rec->intr_flags = intr_flags; 187 rec->next = NULL; 188 rec->serializer = serializer; 189 190 list = &info->i_reclist; 191 192 /* 193 * Keep track of how many fast and slow interrupts we have. 194 */ 195 if (intr_flags & INTR_FAST) 196 ++info->i_fast; 197 else 198 ++info->i_slow; 199 200 /* 201 * Create an emergency polling thread and set up a systimer to wake 202 * it up. 203 */ 204 if (emergency_intr_thread.td_kstack == NULL) { 205 lwkt_create(ithread_emergency, NULL, NULL, 206 &emergency_intr_thread, TDF_STOPREQ|TDF_INTTHREAD, -1, 207 "ithread emerg"); 208 systimer_init_periodic_nq(&emergency_intr_timer, 209 emergency_intr_timer_callback, &emergency_intr_thread, 210 (emergency_intr_enable ? emergency_intr_freq : 1)); 211 } 212 213 /* 214 * Create an interrupt thread if necessary, leave it in an unscheduled 215 * state. 216 */ 217 if (info->i_state == ISTATE_NOTHREAD) { 218 info->i_state = ISTATE_NORMAL; 219 lwkt_create((void *)ithread_handler, (void *)intr, NULL, 220 &info->i_thread, TDF_STOPREQ|TDF_INTTHREAD, -1, 221 "ithread %d", intr); 222 if (intr >= FIRST_SOFTINT) 223 lwkt_setpri(&info->i_thread, TDPRI_SOFT_NORM); 224 else 225 lwkt_setpri(&info->i_thread, TDPRI_INT_MED); 226 info->i_thread.td_preemptable = lwkt_preempt; 227 } 228 229 /* 230 * Add the record to the interrupt list 231 */ 232 crit_enter(); /* token */ 233 while (*list != NULL) 234 list = &(*list)->next; 235 *list = rec; 236 crit_exit(); 237 238 /* 239 * Update max_installed_hard_intr to make the emergency intr poll 240 * a bit more efficient. 241 */ 242 if (intr < FIRST_SOFTINT) { 243 if (max_installed_hard_intr <= intr) 244 max_installed_hard_intr = intr + 1; 245 } else { 246 if (max_installed_soft_intr <= intr) 247 max_installed_soft_intr = intr + 1; 248 } 249 return(rec); 250 } 251 252 int 253 unregister_swi(void *id) 254 { 255 return(unregister_int(id)); 256 } 257 258 int 259 unregister_int(void *id) 260 { 261 struct intr_info *info; 262 struct intrec **list; 263 intrec_t rec; 264 int intr; 265 266 intr = ((intrec_t)id)->intr; 267 268 if (intr < 0 || intr >= MAX_INTS) 269 panic("register_int: bad intr %d", intr); 270 271 info = &intr_info_ary[intr]; 272 273 /* 274 * Remove the interrupt descriptor 275 */ 276 crit_enter(); 277 list = &info->i_reclist; 278 while ((rec = *list) != NULL) { 279 if (rec == id) { 280 *list = rec->next; 281 break; 282 } 283 list = &rec->next; 284 } 285 crit_exit(); 286 287 /* 288 * Free it, adjust interrupt type counts 289 */ 290 if (rec != NULL) { 291 if (rec->intr_flags & INTR_FAST) 292 --info->i_fast; 293 else 294 --info->i_slow; 295 free(rec->name, M_DEVBUF); 296 free(rec, M_DEVBUF); 297 } else { 298 printf("warning: unregister_int: int %d handler for %s not found\n", 299 intr, ((intrec_t)id)->name); 300 } 301 302 /* 303 * Return the number of interrupt vectors still registered on this intr 304 */ 305 return(info->i_fast + info->i_slow); 306 } 307 308 int 309 get_registered_intr(void *id) 310 { 311 return(((intrec_t)id)->intr); 312 } 313 314 const char * 315 get_registered_name(int intr) 316 { 317 intrec_t rec; 318 319 if (intr < 0 || intr >= MAX_INTS) 320 panic("register_int: bad intr %d", intr); 321 322 if ((rec = intr_info_ary[intr].i_reclist) == NULL) 323 return(NULL); 324 else if (rec->next) 325 return("mux"); 326 else 327 return(rec->name); 328 } 329 330 int 331 count_registered_ints(int intr) 332 { 333 struct intr_info *info; 334 335 if (intr < 0 || intr >= MAX_INTS) 336 panic("register_int: bad intr %d", intr); 337 info = &intr_info_ary[intr]; 338 return(info->i_fast + info->i_slow); 339 } 340 341 long 342 get_interrupt_counter(int intr) 343 { 344 struct intr_info *info; 345 346 if (intr < 0 || intr >= MAX_INTS) 347 panic("register_int: bad intr %d", intr); 348 info = &intr_info_ary[intr]; 349 return(info->i_count); 350 } 351 352 353 void 354 swi_setpriority(int intr, int pri) 355 { 356 struct intr_info *info; 357 358 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 359 panic("register_swi: bad intr %d", intr); 360 info = &intr_info_ary[intr]; 361 if (info->i_state != ISTATE_NOTHREAD) 362 lwkt_setpri(&info->i_thread, pri); 363 } 364 365 void 366 register_randintr(int intr) 367 { 368 struct intr_info *info; 369 370 if (intr < 0 || intr >= MAX_INTS) 371 panic("register_randintr: bad intr %d", intr); 372 info = &intr_info_ary[intr]; 373 info->i_random.sc_intr = intr; 374 info->i_random.sc_enabled = 1; 375 } 376 377 void 378 unregister_randintr(int intr) 379 { 380 struct intr_info *info; 381 382 if (intr < 0 || intr >= MAX_INTS) 383 panic("register_swi: bad intr %d", intr); 384 info = &intr_info_ary[intr]; 385 info->i_random.sc_enabled = 0; 386 } 387 388 int 389 next_registered_randintr(int intr) 390 { 391 struct intr_info *info; 392 393 if (intr < 0 || intr >= MAX_INTS) 394 panic("register_swi: bad intr %d", intr); 395 while (intr < MAX_INTS) { 396 info = &intr_info_ary[intr]; 397 if (info->i_random.sc_enabled) 398 break; 399 ++intr; 400 } 401 return(intr); 402 } 403 404 /* 405 * Dispatch an interrupt. If there's nothing to do we have a stray 406 * interrupt and can just return, leaving the interrupt masked. 407 * 408 * We need to schedule the interrupt and set its i_running bit. If 409 * we are not on the interrupt thread's cpu we have to send a message 410 * to the correct cpu that will issue the desired action (interlocking 411 * with the interrupt thread's critical section). We do NOT attempt to 412 * reschedule interrupts whos i_running bit is already set because 413 * this would prematurely wakeup a livelock-limited interrupt thread. 414 * 415 * i_running is only tested/set on the same cpu as the interrupt thread. 416 * 417 * We are NOT in a critical section, which will allow the scheduled 418 * interrupt to preempt us. The MP lock might *NOT* be held here. 419 */ 420 #ifdef SMP 421 422 static void 423 sched_ithd_remote(void *arg) 424 { 425 sched_ithd((int)arg); 426 } 427 428 #endif 429 430 void 431 sched_ithd(int intr) 432 { 433 struct intr_info *info; 434 435 info = &intr_info_ary[intr]; 436 437 ++info->i_count; 438 if (info->i_state != ISTATE_NOTHREAD) { 439 if (info->i_reclist == NULL) { 440 printf("sched_ithd: stray interrupt %d\n", intr); 441 } else { 442 #ifdef SMP 443 if (info->i_thread.td_gd == mycpu) { 444 if (info->i_running == 0) { 445 info->i_running = 1; 446 if (info->i_state != ISTATE_LIVELOCKED) 447 lwkt_schedule(&info->i_thread); /* MIGHT PREEMPT */ 448 } 449 } else { 450 lwkt_send_ipiq(info->i_thread.td_gd, 451 sched_ithd_remote, (void *)intr); 452 } 453 #else 454 if (info->i_running == 0) { 455 info->i_running = 1; 456 if (info->i_state != ISTATE_LIVELOCKED) 457 lwkt_schedule(&info->i_thread); /* MIGHT PREEMPT */ 458 } 459 #endif 460 } 461 } else { 462 printf("sched_ithd: stray interrupt %d\n", intr); 463 } 464 } 465 466 /* 467 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL 468 * might not be held). 469 */ 470 static void 471 ithread_livelock_wakeup(systimer_t st) 472 { 473 struct intr_info *info; 474 475 info = &intr_info_ary[(int)st->data]; 476 if (info->i_state != ISTATE_NOTHREAD) 477 lwkt_schedule(&info->i_thread); 478 } 479 480 /* 481 * This function is called drectly from the ICU or APIC vector code assembly 482 * to process an interrupt. The critical section and interrupt deferral 483 * checks have already been done but the function is entered WITHOUT 484 * a critical section held. The BGL may or may not be held. 485 * 486 * Must return non-zero if we do not want the vector code to re-enable 487 * the interrupt (which we don't if we have to schedule the interrupt) 488 */ 489 int ithread_fast_handler(struct intrframe frame); 490 491 int 492 ithread_fast_handler(struct intrframe frame) 493 { 494 int intr; 495 struct intr_info *info; 496 struct intrec **list; 497 int must_schedule; 498 #ifdef SMP 499 int got_mplock; 500 #endif 501 intrec_t rec, next_rec; 502 globaldata_t gd; 503 504 intr = frame.if_vec; 505 gd = mycpu; 506 507 info = &intr_info_ary[intr]; 508 509 /* 510 * If we are not processing any FAST interrupts, just schedule the thing. 511 * (since we aren't in a critical section, this can result in a 512 * preemption) 513 */ 514 if (info->i_fast == 0) { 515 sched_ithd(intr); 516 return(1); 517 } 518 519 /* 520 * This should not normally occur since interrupts ought to be 521 * masked if the ithread has been scheduled or is running. 522 */ 523 if (info->i_running) 524 return(1); 525 526 /* 527 * Bump the interrupt nesting level to process any FAST interrupts. 528 * Obtain the MP lock as necessary. If the MP lock cannot be obtained, 529 * schedule the interrupt thread to deal with the issue instead. 530 * 531 * To reduce overhead, just leave the MP lock held once it has been 532 * obtained. 533 */ 534 crit_enter_gd(gd); 535 ++gd->gd_intr_nesting_level; 536 ++gd->gd_cnt.v_intr; 537 must_schedule = info->i_slow; 538 #ifdef SMP 539 got_mplock = 0; 540 #endif 541 542 list = &info->i_reclist; 543 for (rec = *list; rec; rec = next_rec) { 544 next_rec = rec->next; /* rec may be invalid after call */ 545 546 if (rec->intr_flags & INTR_FAST) { 547 #ifdef SMP 548 if ((rec->intr_flags & INTR_MPSAFE) == 0 && got_mplock == 0) { 549 if (try_mplock() == 0) { 550 int owner; 551 552 /* 553 * If we couldn't get the MP lock try to forward it 554 * to the cpu holding the MP lock, setting must_schedule 555 * to -1 so we do not schedule and also do not unmask 556 * the interrupt. Otherwise just schedule it. 557 */ 558 owner = owner_mplock(); 559 if (owner >= 0 && owner != gd->gd_cpuid) { 560 lwkt_send_ipiq_bycpu(owner, forward_fastint_remote, 561 (void *)intr); 562 must_schedule = -1; 563 ++gd->gd_cnt.v_forwarded_ints; 564 } else { 565 must_schedule = 1; 566 } 567 break; 568 } 569 got_mplock = 1; 570 } 571 #endif 572 if (rec->serializer) { 573 must_schedule += lwkt_serialize_handler_try( 574 rec->serializer, rec->handler, 575 rec->argument, &frame); 576 } else { 577 rec->handler(rec->argument, &frame); 578 } 579 } 580 } 581 582 /* 583 * Cleanup 584 */ 585 --gd->gd_intr_nesting_level; 586 #ifdef SMP 587 if (got_mplock) 588 rel_mplock(); 589 #endif 590 crit_exit_gd(gd); 591 592 /* 593 * If we had a problem, schedule the thread to catch the missed 594 * records (it will just re-run all of them). A return value of 0 595 * indicates that all handlers have been run and the interrupt can 596 * be re-enabled, and a non-zero return indicates that the interrupt 597 * thread controls re-enablement. 598 */ 599 if (must_schedule > 0) 600 sched_ithd(intr); 601 else if (must_schedule == 0) 602 ++info->i_count; 603 return(must_schedule); 604 } 605 606 #if 0 607 608 6: ; \ 609 /* could not get the MP lock, forward the interrupt */ \ 610 movl mp_lock, %eax ; /* check race */ \ 611 cmpl $MP_FREE_LOCK,%eax ; \ 612 je 2b ; \ 613 incl PCPU(cnt)+V_FORWARDED_INTS ; \ 614 subl $12,%esp ; \ 615 movl $irq_num,8(%esp) ; \ 616 movl $forward_fastint_remote,4(%esp) ; \ 617 movl %eax,(%esp) ; \ 618 call lwkt_send_ipiq_bycpu ; \ 619 addl $12,%esp ; \ 620 jmp 5f ; 621 622 #endif 623 624 625 /* 626 * Interrupt threads run this as their main loop. 627 * 628 * The handler begins execution outside a critical section and with the BGL 629 * held. 630 * 631 * The i_running state starts at 0. When an interrupt occurs, the hardware 632 * interrupt is disabled and sched_ithd() The HW interrupt remains disabled 633 * until all routines have run. We then call ithread_done() to reenable 634 * the HW interrupt and deschedule us until the next interrupt. 635 * 636 * We are responsible for atomically checking i_running and ithread_done() 637 * is responsible for atomically checking for platform-specific delayed 638 * interrupts. i_running for our irq is only set in the context of our cpu, 639 * so a critical section is a sufficient interlock. 640 */ 641 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */ 642 643 static void 644 ithread_handler(void *arg) 645 { 646 struct intr_info *info; 647 int use_limit; 648 int lticks; 649 int lcount; 650 int intr; 651 struct intrec **list; 652 intrec_t rec, nrec; 653 globaldata_t gd; 654 struct systimer ill_timer; /* enforced freq. timer */ 655 u_int ill_count; /* interrupt livelock counter */ 656 657 ill_count = 0; 658 lticks = ticks; 659 lcount = 0; 660 intr = (int)arg; 661 info = &intr_info_ary[intr]; 662 list = &info->i_reclist; 663 gd = mycpu; 664 665 /* 666 * The loop must be entered with one critical section held. 667 */ 668 crit_enter_gd(gd); 669 670 for (;;) { 671 /* 672 * If an interrupt is pending, clear i_running and execute the 673 * handlers. Note that certain types of interrupts can re-trigger 674 * and set i_running again. 675 * 676 * Each handler is run in a critical section. Note that we run both 677 * FAST and SLOW designated service routines. 678 */ 679 if (info->i_running) { 680 ++ill_count; 681 info->i_running = 0; 682 for (rec = *list; rec; rec = nrec) { 683 nrec = rec->next; 684 if (rec->serializer) { 685 lwkt_serialize_handler_call(rec->serializer, rec->handler, 686 rec->argument, NULL); 687 } else { 688 rec->handler(rec->argument, NULL); 689 } 690 } 691 } 692 693 /* 694 * This is our interrupt hook to add rate randomness to the random 695 * number generator. 696 */ 697 if (info->i_random.sc_enabled) 698 add_interrupt_randomness(intr); 699 700 /* 701 * Unmask the interrupt to allow it to trigger again. This only 702 * applies to certain types of interrupts (typ level interrupts). 703 * This can result in the interrupt retriggering, but the retrigger 704 * will not be processed until we cycle our critical section. 705 * 706 * Only unmask interrupts while handlers are installed. It is 707 * possible to hit a situation where no handlers are installed 708 * due to a device driver livelocking and then tearing down its 709 * interrupt on close (the parallel bus being a good example). 710 */ 711 if (*list) 712 machintr_intren(intr); 713 714 /* 715 * Do a quick exit/enter to catch any higher-priority interrupt 716 * sources, such as the statclock, so thread time accounting 717 * will still work. This may also cause an interrupt to re-trigger. 718 */ 719 crit_exit_gd(gd); 720 crit_enter_gd(gd); 721 722 /* 723 * LIVELOCK STATE MACHINE 724 */ 725 switch(info->i_state) { 726 case ISTATE_NORMAL: 727 /* 728 * Calculate a running average every tick. 729 */ 730 if (lticks != ticks) { 731 lticks = ticks; 732 ill_count -= ill_count / hz; 733 } 734 735 /* 736 * If we did not exceed the frequency limit, we are done. 737 * If the interrupt has not retriggered we deschedule ourselves. 738 */ 739 if (ill_count <= livelock_limit) { 740 if (info->i_running == 0) { 741 lwkt_deschedule_self(gd->gd_curthread); 742 lwkt_switch(); 743 } 744 break; 745 } 746 747 /* 748 * Otherwise we are livelocked. Set up a periodic systimer 749 * to wake the thread up at the limit frequency. 750 */ 751 printf("intr %d at %d > %d hz, livelocked limit engaged!\n", 752 intr, livelock_limit, ill_count); 753 info->i_state = ISTATE_LIVELOCKED; 754 if ((use_limit = livelock_limit) < 100) 755 use_limit = 100; 756 else if (use_limit > 500000) 757 use_limit = 500000; 758 systimer_init_periodic(&ill_timer, ithread_livelock_wakeup, 759 (void *)intr, use_limit); 760 lcount = 0; 761 /* fall through */ 762 case ISTATE_LIVELOCKED: 763 /* 764 * Wait for our periodic timer to go off. Since the interrupt 765 * has re-armed it can still set i_running, but it will not 766 * reschedule us while we are in a livelocked state. 767 */ 768 lwkt_deschedule_self(gd->gd_curthread); 769 lwkt_switch(); 770 771 /* 772 * Check to see if the livelock condition no longer applies. 773 * The interrupt must be able to operate normally for one 774 * full second before we restore normal operation. 775 */ 776 if (lticks != ticks) { 777 lticks = ticks; 778 if (ill_count < livelock_lowater) { 779 if (++lcount >= hz) { 780 info->i_state = ISTATE_NORMAL; 781 systimer_del(&ill_timer); 782 printf("intr %d at %d < %d hz, livelock removed\n", 783 intr, ill_count, livelock_lowater); 784 } 785 } else { 786 lcount = 0; 787 } 788 ill_count -= ill_count / hz; 789 } 790 break; 791 } 792 } 793 /* not reached */ 794 } 795 796 /* 797 * Emergency interrupt polling thread. The thread begins execution 798 * outside a critical section with the BGL held. 799 * 800 * If emergency interrupt polling is enabled, this thread will 801 * execute all system interrupts not marked INTR_NOPOLL at the 802 * specified polling frequency. 803 * 804 * WARNING! This thread runs *ALL* interrupt service routines that 805 * are not marked INTR_NOPOLL, which basically means everything except 806 * the 8254 clock interrupt and the ATA interrupt. It has very high 807 * overhead and should only be used in situations where the machine 808 * cannot otherwise be made to work. Due to the severe performance 809 * degredation, it should not be enabled on production machines. 810 */ 811 static void 812 ithread_emergency(void *arg __unused) 813 { 814 struct intr_info *info; 815 intrec_t rec, nrec; 816 int intr; 817 818 for (;;) { 819 for (intr = 0; intr < max_installed_hard_intr; ++intr) { 820 info = &intr_info_ary[intr]; 821 for (rec = info->i_reclist; rec; rec = nrec) { 822 if ((rec->intr_flags & INTR_NOPOLL) == 0) { 823 if (rec->serializer) { 824 lwkt_serialize_handler_call(rec->serializer, 825 rec->handler, rec->argument, NULL); 826 } else { 827 rec->handler(rec->argument, NULL); 828 } 829 } 830 nrec = rec->next; 831 } 832 } 833 lwkt_deschedule_self(curthread); 834 lwkt_switch(); 835 } 836 } 837 838 /* 839 * Systimer callback - schedule the emergency interrupt poll thread 840 * if emergency polling is enabled. 841 */ 842 static 843 void 844 emergency_intr_timer_callback(systimer_t info, struct intrframe *frame __unused) 845 { 846 if (emergency_intr_enable) 847 lwkt_schedule(info->data); 848 } 849 850 /* 851 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 852 * The data for this machine dependent, and the declarations are in machine 853 * dependent code. The layout of intrnames and intrcnt however is machine 854 * independent. 855 * 856 * We do not know the length of intrcnt and intrnames at compile time, so 857 * calculate things at run time. 858 */ 859 860 static int 861 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 862 { 863 struct intr_info *info; 864 intrec_t rec; 865 int error = 0; 866 int len; 867 int intr; 868 char buf[64]; 869 870 for (intr = 0; error == 0 && intr < MAX_INTS; ++intr) { 871 info = &intr_info_ary[intr]; 872 873 len = 0; 874 buf[0] = 0; 875 for (rec = info->i_reclist; rec; rec = rec->next) { 876 snprintf(buf + len, sizeof(buf) - len, "%s%s", 877 (len ? "/" : ""), rec->name); 878 len += strlen(buf + len); 879 } 880 if (len == 0) { 881 snprintf(buf, sizeof(buf), "irq%d", intr); 882 len = strlen(buf); 883 } 884 error = SYSCTL_OUT(req, buf, len + 1); 885 } 886 return (error); 887 } 888 889 890 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 891 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 892 893 static int 894 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 895 { 896 struct intr_info *info; 897 int error = 0; 898 int intr; 899 900 for (intr = 0; intr < max_installed_hard_intr; ++intr) { 901 info = &intr_info_ary[intr]; 902 903 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count)); 904 if (error) 905 goto failed; 906 } 907 for (intr = FIRST_SOFTINT; intr < max_installed_soft_intr; ++intr) { 908 info = &intr_info_ary[intr]; 909 910 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count)); 911 if (error) 912 goto failed; 913 } 914 failed: 915 return(error); 916 } 917 918 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 919 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 920 921