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 1.41 2006/01/25 19:56:21 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 struct info_info; 50 51 typedef struct intrec { 52 struct intrec *next; 53 struct intr_info *info; 54 inthand2_t *handler; 55 void *argument; 56 char *name; 57 int intr; 58 int intr_flags; 59 struct lwkt_serialize *serializer; 60 } *intrec_t; 61 62 struct intr_info { 63 intrec_t i_reclist; 64 struct thread i_thread; 65 struct random_softc i_random; 66 int i_running; 67 long i_count; /* interrupts dispatched */ 68 int i_mplock_required; 69 int i_fast; 70 int i_slow; 71 int i_state; 72 } intr_info_ary[MAX_INTS]; 73 74 int max_installed_hard_intr; 75 int max_installed_soft_intr; 76 77 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000 78 79 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS); 80 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS); 81 static void emergency_intr_timer_callback(systimer_t, struct intrframe *); 82 static void ithread_handler(void *arg); 83 static void ithread_emergency(void *arg); 84 85 int intr_info_size = sizeof(intr_info_ary) / sizeof(intr_info_ary[0]); 86 87 static struct systimer emergency_intr_timer; 88 static struct thread emergency_intr_thread; 89 90 #define ISTATE_NOTHREAD 0 91 #define ISTATE_NORMAL 1 92 #define ISTATE_LIVELOCKED 2 93 94 #ifdef SMP 95 static int intr_mpsafe = 0; 96 TUNABLE_INT("kern.intr_mpsafe", &intr_mpsafe); 97 SYSCTL_INT(_kern, OID_AUTO, intr_mpsafe, 98 CTLFLAG_RW, &intr_mpsafe, 0, "Run INTR_MPSAFE handlers without the BGL"); 99 #endif 100 static int livelock_limit = 50000; 101 static int livelock_lowater = 20000; 102 SYSCTL_INT(_kern, OID_AUTO, livelock_limit, 103 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit"); 104 SYSCTL_INT(_kern, OID_AUTO, livelock_lowater, 105 CTLFLAG_RW, &livelock_lowater, 0, "Livelock low-water mark restore"); 106 107 static int emergency_intr_enable = 0; /* emergency interrupt polling */ 108 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable); 109 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_enable, CTLTYPE_INT | CTLFLAG_RW, 110 0, 0, sysctl_emergency_enable, "I", "Emergency Interrupt Poll Enable"); 111 112 static int emergency_intr_freq = 10; /* emergency polling frequency */ 113 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq); 114 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_freq, CTLTYPE_INT | CTLFLAG_RW, 115 0, 0, sysctl_emergency_freq, "I", "Emergency Interrupt Poll Frequency"); 116 117 /* 118 * Sysctl support routines 119 */ 120 static int 121 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS) 122 { 123 int error, enabled; 124 125 enabled = emergency_intr_enable; 126 error = sysctl_handle_int(oidp, &enabled, 0, req); 127 if (error || req->newptr == NULL) 128 return error; 129 emergency_intr_enable = enabled; 130 if (emergency_intr_enable) { 131 emergency_intr_timer.periodic = 132 sys_cputimer->fromhz(emergency_intr_freq); 133 } else { 134 emergency_intr_timer.periodic = sys_cputimer->fromhz(1); 135 } 136 return 0; 137 } 138 139 static int 140 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS) 141 { 142 int error, phz; 143 144 phz = emergency_intr_freq; 145 error = sysctl_handle_int(oidp, &phz, 0, req); 146 if (error || req->newptr == NULL) 147 return error; 148 if (phz <= 0) 149 return EINVAL; 150 else if (phz > EMERGENCY_INTR_POLLING_FREQ_MAX) 151 phz = EMERGENCY_INTR_POLLING_FREQ_MAX; 152 153 emergency_intr_freq = phz; 154 if (emergency_intr_enable) { 155 emergency_intr_timer.periodic = 156 sys_cputimer->fromhz(emergency_intr_freq); 157 } else { 158 emergency_intr_timer.periodic = sys_cputimer->fromhz(1); 159 } 160 return 0; 161 } 162 163 /* 164 * Register an SWI or INTerrupt handler. 165 */ 166 void * 167 register_swi(int intr, inthand2_t *handler, void *arg, const char *name, 168 struct lwkt_serialize *serializer) 169 { 170 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 171 panic("register_swi: bad intr %d", intr); 172 return(register_int(intr, handler, arg, name, serializer, 0)); 173 } 174 175 void * 176 register_int(int intr, inthand2_t *handler, void *arg, const char *name, 177 struct lwkt_serialize *serializer, int intr_flags) 178 { 179 struct intr_info *info; 180 struct intrec **list; 181 intrec_t rec; 182 183 if (intr < 0 || intr >= MAX_INTS) 184 panic("register_int: bad intr %d", intr); 185 if (name == NULL) 186 name = "???"; 187 info = &intr_info_ary[intr]; 188 189 /* 190 * Construct an interrupt handler record 191 */ 192 rec = malloc(sizeof(struct intrec), M_DEVBUF, M_INTWAIT); 193 rec->name = malloc(strlen(name) + 1, M_DEVBUF, M_INTWAIT); 194 strcpy(rec->name, name); 195 196 rec->info = info; 197 rec->handler = handler; 198 rec->argument = arg; 199 rec->intr = intr; 200 rec->intr_flags = intr_flags; 201 rec->next = NULL; 202 rec->serializer = serializer; 203 204 /* 205 * Create an emergency polling thread and set up a systimer to wake 206 * it up. 207 */ 208 if (emergency_intr_thread.td_kstack == NULL) { 209 lwkt_create(ithread_emergency, NULL, NULL, 210 &emergency_intr_thread, TDF_STOPREQ|TDF_INTTHREAD, -1, 211 "ithread emerg"); 212 systimer_init_periodic_nq(&emergency_intr_timer, 213 emergency_intr_timer_callback, &emergency_intr_thread, 214 (emergency_intr_enable ? emergency_intr_freq : 1)); 215 } 216 217 /* 218 * Create an interrupt thread if necessary, leave it in an unscheduled 219 * state. 220 */ 221 if (info->i_state == ISTATE_NOTHREAD) { 222 info->i_state = ISTATE_NORMAL; 223 lwkt_create((void *)ithread_handler, (void *)intr, NULL, 224 &info->i_thread, TDF_STOPREQ|TDF_INTTHREAD|TDF_MPSAFE, -1, 225 "ithread %d", intr); 226 if (intr >= FIRST_SOFTINT) 227 lwkt_setpri(&info->i_thread, TDPRI_SOFT_NORM); 228 else 229 lwkt_setpri(&info->i_thread, TDPRI_INT_MED); 230 info->i_thread.td_preemptable = lwkt_preempt; 231 } 232 233 list = &info->i_reclist; 234 235 /* 236 * Keep track of how many fast and slow interrupts we have. 237 * Set i_mplock_required if any handler in the chain requires 238 * the MP lock to operate. 239 */ 240 if ((intr_flags & INTR_MPSAFE) == 0) 241 info->i_mplock_required = 1; 242 if (intr_flags & INTR_FAST) 243 ++info->i_fast; 244 else 245 ++info->i_slow; 246 247 /* 248 * Enable random number generation keying off of this interrupt. 249 */ 250 if ((intr_flags & INTR_NOENTROPY) == 0 && info->i_random.sc_enabled == 0) { 251 info->i_random.sc_enabled = 1; 252 info->i_random.sc_intr = intr; 253 } 254 255 /* 256 * Add the record to the interrupt list. 257 */ 258 crit_enter(); 259 while (*list != NULL) 260 list = &(*list)->next; 261 *list = rec; 262 crit_exit(); 263 264 /* 265 * Update max_installed_hard_intr to make the emergency intr poll 266 * a bit more efficient. 267 */ 268 if (intr < FIRST_SOFTINT) { 269 if (max_installed_hard_intr <= intr) 270 max_installed_hard_intr = intr + 1; 271 } else { 272 if (max_installed_soft_intr <= intr) 273 max_installed_soft_intr = intr + 1; 274 } 275 276 /* 277 * Setup the machine level interrupt vector 278 * 279 * XXX temporary workaround for some ACPI brokedness. ACPI installs 280 * its interrupt too early, before the IOAPICs have been configured, 281 * which means the IOAPIC is not enabled by the registration of the 282 * ACPI interrupt. Anything else sharing that IRQ will wind up not 283 * being enabled. Temporarily work around the problem by always 284 * installing and enabling on every new interrupt handler, even 285 * if one has already been setup on that irq. 286 */ 287 if (intr < FIRST_SOFTINT /* && info->i_slow + info->i_fast == 1*/) { 288 if (machintr_vector_setup(intr, intr_flags)) 289 printf("machintr_vector_setup: failed on irq %d\n", intr); 290 } 291 292 return(rec); 293 } 294 295 void 296 unregister_swi(void *id) 297 { 298 unregister_int(id); 299 } 300 301 void 302 unregister_int(void *id) 303 { 304 struct intr_info *info; 305 struct intrec **list; 306 intrec_t rec; 307 int intr; 308 309 intr = ((intrec_t)id)->intr; 310 311 if (intr < 0 || intr >= MAX_INTS) 312 panic("register_int: bad intr %d", intr); 313 314 info = &intr_info_ary[intr]; 315 316 /* 317 * Remove the interrupt descriptor, adjust the descriptor count, 318 * and teardown the machine level vector if this was the last interrupt. 319 */ 320 crit_enter(); 321 list = &info->i_reclist; 322 while ((rec = *list) != NULL) { 323 if (rec == id) 324 break; 325 list = &rec->next; 326 } 327 if (rec) { 328 intrec_t rec0; 329 330 *list = rec->next; 331 if (rec->intr_flags & INTR_FAST) 332 --info->i_fast; 333 else 334 --info->i_slow; 335 if (intr < FIRST_SOFTINT && info->i_fast + info->i_slow == 0) 336 machintr_vector_teardown(intr); 337 338 /* 339 * Clear i_mplock_required if no handlers in the chain require the 340 * MP lock. 341 */ 342 for (rec0 = info->i_reclist; rec0; rec0 = rec0->next) { 343 if ((rec0->intr_flags & INTR_MPSAFE) == 0) 344 break; 345 } 346 if (rec0 == NULL) 347 info->i_mplock_required = 0; 348 } 349 350 crit_exit(); 351 352 /* 353 * Free the record. 354 */ 355 if (rec != NULL) { 356 free(rec->name, M_DEVBUF); 357 free(rec, M_DEVBUF); 358 } else { 359 printf("warning: unregister_int: int %d handler for %s not found\n", 360 intr, ((intrec_t)id)->name); 361 } 362 } 363 364 const char * 365 get_registered_name(int intr) 366 { 367 intrec_t rec; 368 369 if (intr < 0 || intr >= MAX_INTS) 370 panic("register_int: bad intr %d", intr); 371 372 if ((rec = intr_info_ary[intr].i_reclist) == NULL) 373 return(NULL); 374 else if (rec->next) 375 return("mux"); 376 else 377 return(rec->name); 378 } 379 380 int 381 count_registered_ints(int intr) 382 { 383 struct intr_info *info; 384 385 if (intr < 0 || intr >= MAX_INTS) 386 panic("register_int: bad intr %d", intr); 387 info = &intr_info_ary[intr]; 388 return(info->i_fast + info->i_slow); 389 } 390 391 long 392 get_interrupt_counter(int intr) 393 { 394 struct intr_info *info; 395 396 if (intr < 0 || intr >= MAX_INTS) 397 panic("register_int: bad intr %d", intr); 398 info = &intr_info_ary[intr]; 399 return(info->i_count); 400 } 401 402 403 void 404 swi_setpriority(int intr, int pri) 405 { 406 struct intr_info *info; 407 408 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 409 panic("register_swi: bad intr %d", intr); 410 info = &intr_info_ary[intr]; 411 if (info->i_state != ISTATE_NOTHREAD) 412 lwkt_setpri(&info->i_thread, pri); 413 } 414 415 void 416 register_randintr(int intr) 417 { 418 struct intr_info *info; 419 420 if (intr < 0 || intr >= MAX_INTS) 421 panic("register_randintr: bad intr %d", intr); 422 info = &intr_info_ary[intr]; 423 info->i_random.sc_intr = intr; 424 info->i_random.sc_enabled = 1; 425 } 426 427 void 428 unregister_randintr(int intr) 429 { 430 struct intr_info *info; 431 432 if (intr < 0 || intr >= MAX_INTS) 433 panic("register_swi: bad intr %d", intr); 434 info = &intr_info_ary[intr]; 435 info->i_random.sc_enabled = -1; 436 } 437 438 int 439 next_registered_randintr(int intr) 440 { 441 struct intr_info *info; 442 443 if (intr < 0 || intr >= MAX_INTS) 444 panic("register_swi: bad intr %d", intr); 445 while (intr < MAX_INTS) { 446 info = &intr_info_ary[intr]; 447 if (info->i_random.sc_enabled > 0) 448 break; 449 ++intr; 450 } 451 return(intr); 452 } 453 454 /* 455 * Dispatch an interrupt. If there's nothing to do we have a stray 456 * interrupt and can just return, leaving the interrupt masked. 457 * 458 * We need to schedule the interrupt and set its i_running bit. If 459 * we are not on the interrupt thread's cpu we have to send a message 460 * to the correct cpu that will issue the desired action (interlocking 461 * with the interrupt thread's critical section). We do NOT attempt to 462 * reschedule interrupts whos i_running bit is already set because 463 * this would prematurely wakeup a livelock-limited interrupt thread. 464 * 465 * i_running is only tested/set on the same cpu as the interrupt thread. 466 * 467 * We are NOT in a critical section, which will allow the scheduled 468 * interrupt to preempt us. The MP lock might *NOT* be held here. 469 */ 470 #ifdef SMP 471 472 static void 473 sched_ithd_remote(void *arg) 474 { 475 sched_ithd((int)arg); 476 } 477 478 #endif 479 480 void 481 sched_ithd(int intr) 482 { 483 struct intr_info *info; 484 485 info = &intr_info_ary[intr]; 486 487 ++info->i_count; 488 if (info->i_state != ISTATE_NOTHREAD) { 489 if (info->i_reclist == NULL) { 490 printf("sched_ithd: stray interrupt %d\n", intr); 491 } else { 492 #ifdef SMP 493 if (info->i_thread.td_gd == mycpu) { 494 if (info->i_running == 0) { 495 info->i_running = 1; 496 if (info->i_state != ISTATE_LIVELOCKED) 497 lwkt_schedule(&info->i_thread); /* MIGHT PREEMPT */ 498 } 499 } else { 500 lwkt_send_ipiq(info->i_thread.td_gd, 501 sched_ithd_remote, (void *)intr); 502 } 503 #else 504 if (info->i_running == 0) { 505 info->i_running = 1; 506 if (info->i_state != ISTATE_LIVELOCKED) 507 lwkt_schedule(&info->i_thread); /* MIGHT PREEMPT */ 508 } 509 #endif 510 } 511 } else { 512 printf("sched_ithd: stray interrupt %d\n", intr); 513 } 514 } 515 516 /* 517 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL 518 * might not be held). 519 */ 520 static void 521 ithread_livelock_wakeup(systimer_t st) 522 { 523 struct intr_info *info; 524 525 info = &intr_info_ary[(int)st->data]; 526 if (info->i_state != ISTATE_NOTHREAD) 527 lwkt_schedule(&info->i_thread); 528 } 529 530 /* 531 * This function is called drectly from the ICU or APIC vector code assembly 532 * to process an interrupt. The critical section and interrupt deferral 533 * checks have already been done but the function is entered WITHOUT 534 * a critical section held. The BGL may or may not be held. 535 * 536 * Must return non-zero if we do not want the vector code to re-enable 537 * the interrupt (which we don't if we have to schedule the interrupt) 538 */ 539 int ithread_fast_handler(struct intrframe frame); 540 541 int 542 ithread_fast_handler(struct intrframe frame) 543 { 544 int intr; 545 struct intr_info *info; 546 struct intrec **list; 547 int must_schedule; 548 #ifdef SMP 549 int got_mplock; 550 #endif 551 intrec_t rec, next_rec; 552 globaldata_t gd; 553 554 intr = frame.if_vec; 555 gd = mycpu; 556 557 info = &intr_info_ary[intr]; 558 559 /* 560 * If we are not processing any FAST interrupts, just schedule the thing. 561 * (since we aren't in a critical section, this can result in a 562 * preemption) 563 */ 564 if (info->i_fast == 0) { 565 sched_ithd(intr); 566 return(1); 567 } 568 569 /* 570 * This should not normally occur since interrupts ought to be 571 * masked if the ithread has been scheduled or is running. 572 */ 573 if (info->i_running) 574 return(1); 575 576 /* 577 * Bump the interrupt nesting level to process any FAST interrupts. 578 * Obtain the MP lock as necessary. If the MP lock cannot be obtained, 579 * schedule the interrupt thread to deal with the issue instead. 580 * 581 * To reduce overhead, just leave the MP lock held once it has been 582 * obtained. 583 */ 584 crit_enter_gd(gd); 585 ++gd->gd_intr_nesting_level; 586 ++gd->gd_cnt.v_intr; 587 must_schedule = info->i_slow; 588 #ifdef SMP 589 got_mplock = 0; 590 #endif 591 592 list = &info->i_reclist; 593 for (rec = *list; rec; rec = next_rec) { 594 next_rec = rec->next; /* rec may be invalid after call */ 595 596 if (rec->intr_flags & INTR_FAST) { 597 #ifdef SMP 598 if ((rec->intr_flags & INTR_MPSAFE) == 0 && got_mplock == 0) { 599 if (try_mplock() == 0) { 600 int owner; 601 602 /* 603 * If we couldn't get the MP lock try to forward it 604 * to the cpu holding the MP lock, setting must_schedule 605 * to -1 so we do not schedule and also do not unmask 606 * the interrupt. Otherwise just schedule it. 607 */ 608 owner = owner_mplock(); 609 if (owner >= 0 && owner != gd->gd_cpuid) { 610 lwkt_send_ipiq_bycpu(owner, forward_fastint_remote, 611 (void *)intr); 612 must_schedule = -1; 613 ++gd->gd_cnt.v_forwarded_ints; 614 } else { 615 must_schedule = 1; 616 } 617 break; 618 } 619 got_mplock = 1; 620 } 621 #endif 622 if (rec->serializer) { 623 must_schedule += lwkt_serialize_handler_try( 624 rec->serializer, rec->handler, 625 rec->argument, &frame); 626 } else { 627 rec->handler(rec->argument, &frame); 628 } 629 } 630 } 631 632 /* 633 * Cleanup 634 */ 635 --gd->gd_intr_nesting_level; 636 #ifdef SMP 637 if (got_mplock) 638 rel_mplock(); 639 #endif 640 crit_exit_gd(gd); 641 642 /* 643 * If we had a problem, schedule the thread to catch the missed 644 * records (it will just re-run all of them). A return value of 0 645 * indicates that all handlers have been run and the interrupt can 646 * be re-enabled, and a non-zero return indicates that the interrupt 647 * thread controls re-enablement. 648 */ 649 if (must_schedule > 0) 650 sched_ithd(intr); 651 else if (must_schedule == 0) 652 ++info->i_count; 653 return(must_schedule); 654 } 655 656 #if 0 657 658 6: ; \ 659 /* could not get the MP lock, forward the interrupt */ \ 660 movl mp_lock, %eax ; /* check race */ \ 661 cmpl $MP_FREE_LOCK,%eax ; \ 662 je 2b ; \ 663 incl PCPU(cnt)+V_FORWARDED_INTS ; \ 664 subl $12,%esp ; \ 665 movl $irq_num,8(%esp) ; \ 666 movl $forward_fastint_remote,4(%esp) ; \ 667 movl %eax,(%esp) ; \ 668 call lwkt_send_ipiq_bycpu ; \ 669 addl $12,%esp ; \ 670 jmp 5f ; 671 672 #endif 673 674 675 /* 676 * Interrupt threads run this as their main loop. 677 * 678 * The handler begins execution outside a critical section and with the BGL 679 * held. 680 * 681 * The i_running state starts at 0. When an interrupt occurs, the hardware 682 * interrupt is disabled and sched_ithd() The HW interrupt remains disabled 683 * until all routines have run. We then call ithread_done() to reenable 684 * the HW interrupt and deschedule us until the next interrupt. 685 * 686 * We are responsible for atomically checking i_running and ithread_done() 687 * is responsible for atomically checking for platform-specific delayed 688 * interrupts. i_running for our irq is only set in the context of our cpu, 689 * so a critical section is a sufficient interlock. 690 */ 691 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */ 692 693 static void 694 ithread_handler(void *arg) 695 { 696 struct intr_info *info; 697 int use_limit; 698 int lticks; 699 int lcount; 700 int intr; 701 int mpheld; 702 struct intrec **list; 703 intrec_t rec, nrec; 704 globaldata_t gd; 705 struct systimer ill_timer; /* enforced freq. timer */ 706 u_int ill_count; /* interrupt livelock counter */ 707 708 ill_count = 0; 709 lticks = ticks; 710 lcount = 0; 711 intr = (int)arg; 712 info = &intr_info_ary[intr]; 713 list = &info->i_reclist; 714 gd = mycpu; 715 716 /* 717 * The loop must be entered with one critical section held. The thread 718 * is created with TDF_MPSAFE so the MP lock is not held on start. 719 */ 720 crit_enter_gd(gd); 721 mpheld = 0; 722 723 for (;;) { 724 /* 725 * The chain is only considered MPSAFE if all its interrupt handlers 726 * are MPSAFE. However, if intr_mpsafe has been turned off we 727 * always operate with the BGL. 728 */ 729 #ifdef SMP 730 if (intr_mpsafe == 0) { 731 if (mpheld == 0) { 732 get_mplock(); 733 mpheld = 1; 734 } 735 } else if (info->i_mplock_required != mpheld) { 736 if (info->i_mplock_required) { 737 KKASSERT(mpheld == 0); 738 get_mplock(); 739 mpheld = 1; 740 } else { 741 KKASSERT(mpheld != 0); 742 rel_mplock(); 743 mpheld = 0; 744 } 745 } 746 #endif 747 748 /* 749 * If an interrupt is pending, clear i_running and execute the 750 * handlers. Note that certain types of interrupts can re-trigger 751 * and set i_running again. 752 * 753 * Each handler is run in a critical section. Note that we run both 754 * FAST and SLOW designated service routines. 755 */ 756 if (info->i_running) { 757 ++ill_count; 758 info->i_running = 0; 759 760 for (rec = *list; rec; rec = nrec) { 761 nrec = rec->next; 762 if (rec->serializer) { 763 lwkt_serialize_handler_call(rec->serializer, rec->handler, 764 rec->argument, NULL); 765 } else { 766 rec->handler(rec->argument, NULL); 767 } 768 } 769 } 770 771 /* 772 * This is our interrupt hook to add rate randomness to the random 773 * number generator. 774 */ 775 if (info->i_random.sc_enabled > 0) 776 add_interrupt_randomness(intr); 777 778 /* 779 * Unmask the interrupt to allow it to trigger again. This only 780 * applies to certain types of interrupts (typ level interrupts). 781 * This can result in the interrupt retriggering, but the retrigger 782 * will not be processed until we cycle our critical section. 783 * 784 * Only unmask interrupts while handlers are installed. It is 785 * possible to hit a situation where no handlers are installed 786 * due to a device driver livelocking and then tearing down its 787 * interrupt on close (the parallel bus being a good example). 788 */ 789 if (*list) 790 machintr_intren(intr); 791 792 /* 793 * Do a quick exit/enter to catch any higher-priority interrupt 794 * sources, such as the statclock, so thread time accounting 795 * will still work. This may also cause an interrupt to re-trigger. 796 */ 797 crit_exit_gd(gd); 798 crit_enter_gd(gd); 799 800 /* 801 * LIVELOCK STATE MACHINE 802 */ 803 switch(info->i_state) { 804 case ISTATE_NORMAL: 805 /* 806 * Calculate a running average every tick. 807 */ 808 if (lticks != ticks) { 809 lticks = ticks; 810 ill_count -= ill_count / hz; 811 } 812 813 /* 814 * If we did not exceed the frequency limit, we are done. 815 * If the interrupt has not retriggered we deschedule ourselves. 816 */ 817 if (ill_count <= livelock_limit) { 818 if (info->i_running == 0) { 819 lwkt_deschedule_self(gd->gd_curthread); 820 lwkt_switch(); 821 } 822 break; 823 } 824 825 /* 826 * Otherwise we are livelocked. Set up a periodic systimer 827 * to wake the thread up at the limit frequency. 828 */ 829 printf("intr %d at %d > %d hz, livelocked limit engaged!\n", 830 intr, ill_count, livelock_limit); 831 info->i_state = ISTATE_LIVELOCKED; 832 if ((use_limit = livelock_limit) < 100) 833 use_limit = 100; 834 else if (use_limit > 500000) 835 use_limit = 500000; 836 systimer_init_periodic(&ill_timer, ithread_livelock_wakeup, 837 (void *)intr, use_limit); 838 lcount = 0; 839 /* fall through */ 840 case ISTATE_LIVELOCKED: 841 /* 842 * Wait for our periodic timer to go off. Since the interrupt 843 * has re-armed it can still set i_running, but it will not 844 * reschedule us while we are in a livelocked state. 845 */ 846 lwkt_deschedule_self(gd->gd_curthread); 847 lwkt_switch(); 848 849 /* 850 * Check to see if the livelock condition no longer applies. 851 * The interrupt must be able to operate normally for one 852 * full second before we restore normal operation. 853 */ 854 if (lticks != ticks) { 855 lticks = ticks; 856 if (ill_count < livelock_lowater) { 857 if (++lcount >= hz) { 858 info->i_state = ISTATE_NORMAL; 859 systimer_del(&ill_timer); 860 printf("intr %d at %d < %d hz, livelock removed\n", 861 intr, ill_count, livelock_lowater); 862 } 863 } else { 864 lcount = 0; 865 } 866 ill_count -= ill_count / hz; 867 } 868 break; 869 } 870 } 871 /* not reached */ 872 } 873 874 /* 875 * Emergency interrupt polling thread. The thread begins execution 876 * outside a critical section with the BGL held. 877 * 878 * If emergency interrupt polling is enabled, this thread will 879 * execute all system interrupts not marked INTR_NOPOLL at the 880 * specified polling frequency. 881 * 882 * WARNING! This thread runs *ALL* interrupt service routines that 883 * are not marked INTR_NOPOLL, which basically means everything except 884 * the 8254 clock interrupt and the ATA interrupt. It has very high 885 * overhead and should only be used in situations where the machine 886 * cannot otherwise be made to work. Due to the severe performance 887 * degredation, it should not be enabled on production machines. 888 */ 889 static void 890 ithread_emergency(void *arg __unused) 891 { 892 struct intr_info *info; 893 intrec_t rec, nrec; 894 int intr; 895 896 for (;;) { 897 for (intr = 0; intr < max_installed_hard_intr; ++intr) { 898 info = &intr_info_ary[intr]; 899 for (rec = info->i_reclist; rec; rec = nrec) { 900 if ((rec->intr_flags & INTR_NOPOLL) == 0) { 901 if (rec->serializer) { 902 lwkt_serialize_handler_call(rec->serializer, 903 rec->handler, rec->argument, NULL); 904 } else { 905 rec->handler(rec->argument, NULL); 906 } 907 } 908 nrec = rec->next; 909 } 910 } 911 lwkt_deschedule_self(curthread); 912 lwkt_switch(); 913 } 914 } 915 916 /* 917 * Systimer callback - schedule the emergency interrupt poll thread 918 * if emergency polling is enabled. 919 */ 920 static 921 void 922 emergency_intr_timer_callback(systimer_t info, struct intrframe *frame __unused) 923 { 924 if (emergency_intr_enable) 925 lwkt_schedule(info->data); 926 } 927 928 /* 929 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 930 * The data for this machine dependent, and the declarations are in machine 931 * dependent code. The layout of intrnames and intrcnt however is machine 932 * independent. 933 * 934 * We do not know the length of intrcnt and intrnames at compile time, so 935 * calculate things at run time. 936 */ 937 938 static int 939 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 940 { 941 struct intr_info *info; 942 intrec_t rec; 943 int error = 0; 944 int len; 945 int intr; 946 char buf[64]; 947 948 for (intr = 0; error == 0 && intr < MAX_INTS; ++intr) { 949 info = &intr_info_ary[intr]; 950 951 len = 0; 952 buf[0] = 0; 953 for (rec = info->i_reclist; rec; rec = rec->next) { 954 snprintf(buf + len, sizeof(buf) - len, "%s%s", 955 (len ? "/" : ""), rec->name); 956 len += strlen(buf + len); 957 } 958 if (len == 0) { 959 snprintf(buf, sizeof(buf), "irq%d", intr); 960 len = strlen(buf); 961 } 962 error = SYSCTL_OUT(req, buf, len + 1); 963 } 964 return (error); 965 } 966 967 968 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 969 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 970 971 static int 972 sysctl_intrcnt(SYSCTL_HANDLER_ARGS) 973 { 974 struct intr_info *info; 975 int error = 0; 976 int intr; 977 978 for (intr = 0; intr < max_installed_hard_intr; ++intr) { 979 info = &intr_info_ary[intr]; 980 981 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count)); 982 if (error) 983 goto failed; 984 } 985 for (intr = FIRST_SOFTINT; intr < max_installed_soft_intr; ++intr) { 986 info = &intr_info_ary[intr]; 987 988 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count)); 989 if (error) 990 goto failed; 991 } 992 failed: 993 return(error); 994 } 995 996 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 997 NULL, 0, sysctl_intrcnt, "", "Interrupt Counts"); 998 999