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 * 28 */ 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/malloc.h> 33 #include <sys/kernel.h> 34 #include <sys/sysctl.h> 35 #include <sys/thread.h> 36 #include <sys/proc.h> 37 #include <sys/random.h> 38 #include <sys/serialize.h> 39 #include <sys/interrupt.h> 40 #include <sys/bus.h> 41 #include <sys/machintr.h> 42 43 #include <machine/frame.h> 44 45 #include <sys/thread2.h> 46 #include <sys/mplock2.h> 47 48 struct intr_info; 49 50 typedef struct intrec { 51 struct intrec *next; 52 struct intr_info *info; 53 inthand2_t *handler; 54 void *argument; 55 char *name; 56 int intr; 57 int intr_flags; 58 struct lwkt_serialize *serializer; 59 } *intrec_t; 60 61 struct intr_info { 62 intrec_t i_reclist; 63 struct thread *i_thread; /* don't embed struct thread */ 64 struct random_softc i_random; 65 long i_count; /* interrupts dispatched */ 66 int i_running; 67 short i_mplock_required; 68 short i_flags; 69 int i_fast; 70 int i_slow; 71 int i_state; 72 int i_errorticks; 73 unsigned long i_straycount; 74 int i_cpuid; 75 int i_intr; 76 }; 77 78 struct intr_info_block { 79 struct intr_info ary[MAXCPU][MAX_INTS]; 80 }; 81 82 static struct intr_info_block *intr_block; 83 static struct intr_info *swi_info_ary[MAX_SOFTINTS]; 84 85 static int max_installed_hard_intr[MAXCPU]; 86 87 MALLOC_DEFINE(M_INTRMNG, "intrmng", "interrupt management"); 88 89 90 #define EMERGENCY_INTR_POLLING_FREQ_MAX 20000 91 92 /* 93 * Assert that callers into interrupt handlers don't return with 94 * dangling tokens, spinlocks, or mp locks. 95 */ 96 #ifdef INVARIANTS 97 98 #define TD_INVARIANTS_DECLARE \ 99 int spincount; \ 100 lwkt_tokref_t curstop 101 102 #define TD_INVARIANTS_GET(td) \ 103 do { \ 104 spincount = (td)->td_gd->gd_spinlocks; \ 105 curstop = (td)->td_toks_stop; \ 106 } while(0) 107 108 #define TD_INVARIANTS_TEST(td, name) \ 109 do { \ 110 KASSERT(spincount == (td)->td_gd->gd_spinlocks, \ 111 ("spincount mismatch after interrupt handler %s", \ 112 name)); \ 113 KASSERT(curstop == (td)->td_toks_stop, \ 114 ("token count mismatch after interrupt handler %s", \ 115 name)); \ 116 } while(0) 117 118 #else 119 120 /* !INVARIANTS */ 121 122 #define TD_INVARIANTS_DECLARE 123 #define TD_INVARIANTS_GET(td) 124 #define TD_INVARIANTS_TEST(td, name) 125 126 #endif /* ndef INVARIANTS */ 127 128 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS); 129 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS); 130 static void emergency_intr_timer_callback(systimer_t, int, struct intrframe *); 131 static void ithread_handler(void *arg); 132 static void ithread_emergency(void *arg); 133 static void report_stray_interrupt(struct intr_info *info, const char *func); 134 static void int_moveto_destcpu(int *, int); 135 static void int_moveto_origcpu(int, int); 136 static void sched_ithd_intern(struct intr_info *info); 137 138 static struct systimer emergency_intr_timer[MAXCPU]; 139 static struct thread *emergency_intr_thread[MAXCPU]; 140 141 #define ISTATE_NOTHREAD 0 142 #define ISTATE_NORMAL 1 143 #define ISTATE_LIVELOCKED 2 144 145 static int livelock_limit = 40000; 146 static int livelock_limit_hi = 120000; 147 static int livelock_lowater = 20000; 148 static int livelock_debug = -1; 149 SYSCTL_INT(_kern, OID_AUTO, livelock_limit, 150 CTLFLAG_RW, &livelock_limit, 0, "Livelock interrupt rate limit"); 151 SYSCTL_INT(_kern, OID_AUTO, livelock_limit_hi, 152 CTLFLAG_RW, &livelock_limit_hi, 0, 153 "Livelock interrupt rate limit (high frequency)"); 154 SYSCTL_INT(_kern, OID_AUTO, livelock_lowater, 155 CTLFLAG_RW, &livelock_lowater, 0, "Livelock low-water mark restore"); 156 SYSCTL_INT(_kern, OID_AUTO, livelock_debug, 157 CTLFLAG_RW, &livelock_debug, 0, "Livelock debug intr#"); 158 159 static int emergency_intr_enable = 0; /* emergency interrupt polling */ 160 TUNABLE_INT("kern.emergency_intr_enable", &emergency_intr_enable); 161 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_enable, CTLTYPE_INT | CTLFLAG_RW, 162 0, 0, sysctl_emergency_enable, "I", "Emergency Interrupt Poll Enable"); 163 164 static int emergency_intr_freq = 10; /* emergency polling frequency */ 165 TUNABLE_INT("kern.emergency_intr_freq", &emergency_intr_freq); 166 SYSCTL_PROC(_kern, OID_AUTO, emergency_intr_freq, CTLTYPE_INT | CTLFLAG_RW, 167 0, 0, sysctl_emergency_freq, "I", "Emergency Interrupt Poll Frequency"); 168 169 /* 170 * Sysctl support routines 171 */ 172 static int sysctl_emergency_enable(SYSCTL_HANDLER_ARGS)173 sysctl_emergency_enable(SYSCTL_HANDLER_ARGS) 174 { 175 int error, enabled, cpuid, freq, origcpu; 176 177 enabled = emergency_intr_enable; 178 error = sysctl_handle_int(oidp, &enabled, 0, req); 179 if (error || req->newptr == NULL) 180 return error; 181 emergency_intr_enable = enabled; 182 if (emergency_intr_enable) 183 freq = emergency_intr_freq; 184 else 185 freq = 1; 186 187 origcpu = mycpuid; 188 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 189 lwkt_migratecpu(cpuid); 190 systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq); 191 } 192 lwkt_migratecpu(origcpu); 193 return 0; 194 } 195 196 static int sysctl_emergency_freq(SYSCTL_HANDLER_ARGS)197 sysctl_emergency_freq(SYSCTL_HANDLER_ARGS) 198 { 199 int error, phz, cpuid, freq, origcpu; 200 201 phz = emergency_intr_freq; 202 error = sysctl_handle_int(oidp, &phz, 0, req); 203 if (error || req->newptr == NULL) 204 return error; 205 if (phz <= 0) 206 return EINVAL; 207 else if (phz > EMERGENCY_INTR_POLLING_FREQ_MAX) 208 phz = EMERGENCY_INTR_POLLING_FREQ_MAX; 209 210 emergency_intr_freq = phz; 211 if (emergency_intr_enable) 212 freq = emergency_intr_freq; 213 else 214 freq = 1; 215 216 origcpu = mycpuid; 217 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 218 lwkt_migratecpu(cpuid); 219 systimer_adjust_periodic(&emergency_intr_timer[cpuid], freq); 220 } 221 lwkt_migratecpu(origcpu); 222 return 0; 223 } 224 225 /* 226 * Register an SWI or INTerrupt handler. 227 */ 228 void * register_swi(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)229 register_swi(int intr, inthand2_t *handler, void *arg, const char *name, 230 struct lwkt_serialize *serializer, int cpuid) 231 { 232 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 233 panic("register_swi: bad intr %d", intr); 234 235 if (cpuid < 0) 236 cpuid = intr % ncpus; 237 return(register_int(intr, handler, arg, name, serializer, 0, cpuid)); 238 } 239 240 void * register_swi_mp(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int cpuid)241 register_swi_mp(int intr, inthand2_t *handler, void *arg, const char *name, 242 struct lwkt_serialize *serializer, int cpuid) 243 { 244 if (intr < FIRST_SOFTINT || intr >= MAX_INTS) 245 panic("register_swi: bad intr %d", intr); 246 247 if (cpuid < 0) 248 cpuid = intr % ncpus; 249 return(register_int(intr, handler, arg, name, serializer, 250 INTR_MPSAFE, cpuid)); 251 } 252 253 void * register_int(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags,int cpuid)254 register_int(int intr, inthand2_t *handler, void *arg, const char *name, 255 struct lwkt_serialize *serializer, int intr_flags, int cpuid) 256 { 257 struct intr_info *info; 258 struct intrec **list; 259 intrec_t rec = NULL; 260 int orig_cpuid; 261 262 KKASSERT(cpuid >= 0 && cpuid < ncpus); 263 264 if (intr < 0 || intr >= MAX_INTS) 265 panic("register_int: bad intr %d", intr); 266 if (name == NULL) 267 name = "???"; 268 info = &intr_block->ary[cpuid][intr]; 269 270 int_moveto_destcpu(&orig_cpuid, cpuid); 271 272 /* 273 * This intr has been registered as exclusive one, so 274 * it can't shared. 275 */ 276 if (info->i_flags & INTR_EXCL) 277 goto done; 278 279 /* 280 * This intr has been registered as shared one, so it 281 * can't be used for exclusive handler. 282 */ 283 list = &info->i_reclist; 284 if ((intr_flags & INTR_EXCL) && *list != NULL) 285 goto done; 286 287 /* 288 * Construct an interrupt handler record 289 */ 290 rec = kmalloc(sizeof(struct intrec), M_DEVBUF, M_INTWAIT); 291 rec->name = kmalloc(strlen(name) + 1, M_DEVBUF, M_INTWAIT); 292 strcpy(rec->name, name); 293 294 rec->info = info; 295 rec->handler = handler; 296 rec->argument = arg; 297 rec->intr = intr; 298 rec->intr_flags = intr_flags; 299 rec->next = NULL; 300 rec->serializer = serializer; 301 302 /* 303 * Create an emergency polling thread and set up a systimer to wake 304 * it up. objcache isn't operational yet so use kmalloc. 305 * 306 * objcache may not be operational yet, use kmalloc(). 307 */ 308 if (emergency_intr_thread[cpuid] == NULL) { 309 emergency_intr_thread[cpuid] = kmalloc(sizeof(struct thread), M_DEVBUF, 310 M_INTWAIT | M_ZERO); 311 lwkt_create(ithread_emergency, NULL, NULL, 312 emergency_intr_thread[cpuid], 313 TDF_NOSTART | TDF_INTTHREAD, cpuid, "ithreadE %d", 314 cpuid); 315 systimer_init_periodic_nq(&emergency_intr_timer[cpuid], 316 emergency_intr_timer_callback, 317 emergency_intr_thread[cpuid], 318 (emergency_intr_enable ? emergency_intr_freq : 1)); 319 } 320 321 /* 322 * Create an interrupt thread if necessary, leave it in an unscheduled 323 * state. 324 */ 325 if (info->i_state == ISTATE_NOTHREAD) { 326 info->i_state = ISTATE_NORMAL; 327 info->i_thread = kmalloc(sizeof(struct thread), M_DEVBUF, 328 M_INTWAIT | M_ZERO); 329 lwkt_create(ithread_handler, (void *)(intptr_t)intr, NULL, 330 info->i_thread, TDF_NOSTART | TDF_INTTHREAD, cpuid, 331 "ithread%d %d", intr, cpuid); 332 if (intr >= FIRST_SOFTINT) 333 lwkt_setpri(info->i_thread, TDPRI_SOFT_NORM); 334 else 335 lwkt_setpri(info->i_thread, TDPRI_INT_MED); 336 info->i_thread->td_preemptable = lwkt_preempt; 337 } 338 339 /* 340 * Keep track of how many fast and slow interrupts we have. 341 * Set i_mplock_required if any handler in the chain requires 342 * the MP lock to operate. 343 */ 344 if ((intr_flags & INTR_MPSAFE) == 0) { 345 info->i_mplock_required = 1; 346 kprintf("interrupt uses mplock: %s\n", name); 347 } 348 if (intr_flags & INTR_CLOCK) { 349 atomic_set_int(&info->i_thread->td_flags, TDF_CLKTHREAD); 350 ++info->i_fast; 351 } else { 352 ++info->i_slow; 353 } 354 355 info->i_flags |= (intr_flags & INTR_EXCL); 356 if (info->i_slow + info->i_fast == 1 && (intr_flags & INTR_HIFREQ)) { 357 /* 358 * Allow high frequency interrupt, if this intr is not 359 * shared yet. 360 */ 361 info->i_flags |= INTR_HIFREQ; 362 } else { 363 info->i_flags &= ~INTR_HIFREQ; 364 } 365 366 /* 367 * Enable random number generation keying off of this interrupt. 368 */ 369 if ((intr_flags & INTR_NOENTROPY) == 0 && info->i_random.sc_enabled == 0) { 370 info->i_random.sc_enabled = 1; 371 info->i_random.sc_intr = intr; 372 } 373 374 /* 375 * Add the record to the interrupt list. 376 */ 377 crit_enter(); 378 while (*list != NULL) 379 list = &(*list)->next; 380 *list = rec; 381 crit_exit(); 382 383 /* 384 * Update max_installed_hard_intr to make the emergency intr poll 385 * a bit more efficient. 386 */ 387 if (intr < FIRST_SOFTINT) { 388 if (max_installed_hard_intr[cpuid] <= intr) 389 max_installed_hard_intr[cpuid] = intr + 1; 390 } 391 392 if (intr >= FIRST_SOFTINT) 393 swi_info_ary[intr - FIRST_SOFTINT] = info; 394 395 /* 396 * Setup the machine level interrupt vector 397 */ 398 if (intr < FIRST_SOFTINT && info->i_slow + info->i_fast == 1) 399 machintr_intr_setup(intr, intr_flags); 400 401 done: 402 int_moveto_origcpu(orig_cpuid, cpuid); 403 return(rec); 404 } 405 406 void unregister_swi(void * id,int intr,int cpuid)407 unregister_swi(void *id, int intr, int cpuid) 408 { 409 if (cpuid < 0) 410 cpuid = intr % ncpus; 411 412 unregister_int(id, cpuid); 413 } 414 415 void unregister_int(void * id,int cpuid)416 unregister_int(void *id, int cpuid) 417 { 418 struct intr_info *info; 419 struct intrec **list; 420 intrec_t rec; 421 int intr, orig_cpuid; 422 423 KKASSERT(cpuid >= 0 && cpuid < ncpus); 424 425 intr = ((intrec_t)id)->intr; 426 427 if (intr < 0 || intr >= MAX_INTS) 428 panic("register_int: bad intr %d", intr); 429 430 info = &intr_block->ary[cpuid][intr]; 431 432 int_moveto_destcpu(&orig_cpuid, cpuid); 433 434 /* 435 * Remove the interrupt descriptor, adjust the descriptor count, 436 * and teardown the machine level vector if this was the last interrupt. 437 */ 438 crit_enter(); 439 list = &info->i_reclist; 440 while ((rec = *list) != NULL) { 441 if (rec == id) 442 break; 443 list = &rec->next; 444 } 445 if (rec) { 446 intrec_t rec0; 447 448 *list = rec->next; 449 if (rec->intr_flags & INTR_CLOCK) 450 --info->i_fast; 451 else 452 --info->i_slow; 453 if (intr < FIRST_SOFTINT && info->i_fast + info->i_slow == 0) 454 machintr_intr_teardown(intr); 455 456 /* 457 * Clear i_mplock_required if no handlers in the chain require the 458 * MP lock. 459 */ 460 for (rec0 = info->i_reclist; rec0; rec0 = rec0->next) { 461 if ((rec0->intr_flags & INTR_MPSAFE) == 0) 462 break; 463 } 464 if (rec0 == NULL) 465 info->i_mplock_required = 0; 466 } 467 468 if (info->i_reclist == NULL) { 469 info->i_flags = 0; 470 if (intr >= FIRST_SOFTINT) 471 swi_info_ary[intr - FIRST_SOFTINT] = NULL; 472 } else if (info->i_fast + info->i_slow == 1 && 473 (info->i_reclist->intr_flags & INTR_HIFREQ)) { 474 /* Unshared high frequency interrupt. */ 475 info->i_flags |= INTR_HIFREQ; 476 } 477 478 crit_exit(); 479 480 int_moveto_origcpu(orig_cpuid, cpuid); 481 482 /* 483 * Free the record. 484 */ 485 if (rec != NULL) { 486 kfree(rec->name, M_DEVBUF); 487 kfree(rec, M_DEVBUF); 488 } else { 489 kprintf("warning: unregister_int: int %d handler for %s not found\n", 490 intr, ((intrec_t)id)->name); 491 } 492 } 493 494 long get_interrupt_counter(int intr,int cpuid)495 get_interrupt_counter(int intr, int cpuid) 496 { 497 struct intr_info *info; 498 499 KKASSERT(cpuid >= 0 && cpuid < ncpus); 500 501 if (intr < 0 || intr >= MAX_INTS) 502 panic("register_int: bad intr %d", intr); 503 info = &intr_block->ary[cpuid][intr]; 504 return(info->i_count); 505 } 506 507 void register_randintr(int intr)508 register_randintr(int intr) 509 { 510 struct intr_info *info; 511 int cpuid; 512 513 if (intr < 0 || intr >= MAX_INTS) 514 panic("register_randintr: bad intr %d", intr); 515 516 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 517 info = &intr_block->ary[cpuid][intr]; 518 info->i_random.sc_intr = intr; 519 info->i_random.sc_enabled = 1; 520 } 521 } 522 523 void unregister_randintr(int intr)524 unregister_randintr(int intr) 525 { 526 struct intr_info *info; 527 int cpuid; 528 529 if (intr < 0 || intr >= MAX_INTS) 530 panic("register_swi: bad intr %d", intr); 531 532 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 533 info = &intr_block->ary[cpuid][intr]; 534 info->i_random.sc_enabled = -1; 535 } 536 } 537 538 int next_registered_randintr(int intr)539 next_registered_randintr(int intr) 540 { 541 struct intr_info *info; 542 543 if (intr < 0 || intr >= MAX_INTS) 544 panic("register_swi: bad intr %d", intr); 545 546 while (intr < MAX_INTS) { 547 int cpuid; 548 549 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 550 info = &intr_block->ary[cpuid][intr]; 551 if (info->i_random.sc_enabled > 0) 552 return intr; 553 } 554 ++intr; 555 } 556 return intr; 557 } 558 559 /* 560 * Dispatch an interrupt. If there's nothing to do we have a stray 561 * interrupt and can just return, leaving the interrupt masked. 562 * 563 * We need to schedule the interrupt and set its i_running bit. If 564 * we are not on the interrupt thread's cpu we have to send a message 565 * to the correct cpu that will issue the desired action (interlocking 566 * with the interrupt thread's critical section). We do NOT attempt to 567 * reschedule interrupts whos i_running bit is already set because 568 * this would prematurely wakeup a livelock-limited interrupt thread. 569 * 570 * i_running is only tested/set on the same cpu as the interrupt thread. 571 * 572 * We are NOT in a critical section, which will allow the scheduled 573 * interrupt to preempt us. The MP lock might *NOT* be held here. 574 */ 575 static void sched_ithd_remote(void * arg)576 sched_ithd_remote(void *arg) 577 { 578 sched_ithd_intern(arg); 579 } 580 581 static void sched_ithd_intern(struct intr_info * info)582 sched_ithd_intern(struct intr_info *info) 583 { 584 ++info->i_count; 585 if (info->i_state != ISTATE_NOTHREAD) { 586 if (info->i_reclist == NULL) { 587 report_stray_interrupt(info, "sched_ithd"); 588 } else { 589 if (info->i_thread->td_gd == mycpu) { 590 if (info->i_running == 0) { 591 info->i_running = 1; 592 if (info->i_state != ISTATE_LIVELOCKED) 593 lwkt_schedule(info->i_thread); /* MIGHT PREEMPT */ 594 } 595 } else { 596 lwkt_send_ipiq(info->i_thread->td_gd, sched_ithd_remote, info); 597 } 598 } 599 } else { 600 report_stray_interrupt(info, "sched_ithd"); 601 } 602 } 603 604 void sched_ithd_soft(int intr)605 sched_ithd_soft(int intr) 606 { 607 struct intr_info *info; 608 609 KKASSERT(intr >= FIRST_SOFTINT && intr < MAX_INTS); 610 611 info = swi_info_ary[intr - FIRST_SOFTINT]; 612 if (info != NULL) { 613 sched_ithd_intern(info); 614 } else { 615 kprintf("unregistered softint %d got scheduled on cpu%d\n", 616 intr, mycpuid); 617 } 618 } 619 620 void sched_ithd_hard(int intr)621 sched_ithd_hard(int intr) 622 { 623 KKASSERT(intr >= 0 && intr < MAX_HARDINTS); 624 sched_ithd_intern(&intr_block->ary[mycpuid][intr]); 625 } 626 627 #ifdef _KERNEL_VIRTUAL 628 629 void sched_ithd_hard_virtual(int intr)630 sched_ithd_hard_virtual(int intr) 631 { 632 KKASSERT(intr >= 0 && intr < MAX_HARDINTS); 633 sched_ithd_intern(&intr_block->ary[0][intr]); 634 } 635 636 void * register_int_virtual(int intr,inthand2_t * handler,void * arg,const char * name,struct lwkt_serialize * serializer,int intr_flags)637 register_int_virtual(int intr, inthand2_t *handler, void *arg, const char *name, 638 struct lwkt_serialize *serializer, int intr_flags) 639 { 640 return register_int(intr, handler, arg, name, serializer, intr_flags, 0); 641 } 642 643 void unregister_int_virtual(void * id)644 unregister_int_virtual(void *id) 645 { 646 unregister_int(id, 0); 647 } 648 649 #endif /* _KERN_VIRTUAL */ 650 651 static void report_stray_interrupt(struct intr_info * info,const char * func)652 report_stray_interrupt(struct intr_info *info, const char *func) 653 { 654 ++info->i_straycount; 655 if (info->i_straycount < 10) { 656 if (info->i_errorticks == ticks) 657 return; 658 info->i_errorticks = ticks; 659 kprintf("%s: stray interrupt %d on cpu%d\n", 660 func, info->i_intr, mycpuid); 661 } else if (info->i_straycount == 10) { 662 kprintf("%s: %ld stray interrupts %d on cpu%d - " 663 "there will be no further reports\n", func, 664 info->i_straycount, info->i_intr, mycpuid); 665 } 666 } 667 668 /* 669 * This is run from a periodic SYSTIMER (and thus must be MP safe, the BGL 670 * might not be held). 671 */ 672 static void ithread_livelock_wakeup(systimer_t st,int in_ipi __unused,struct intrframe * frame __unused)673 ithread_livelock_wakeup(systimer_t st, int in_ipi __unused, 674 struct intrframe *frame __unused) 675 { 676 struct intr_info *info; 677 678 info = &intr_block->ary[mycpuid][(int)(intptr_t)st->data]; 679 if (info->i_state != ISTATE_NOTHREAD) 680 lwkt_schedule(info->i_thread); 681 } 682 683 /* 684 * Schedule ithread within fast intr handler 685 * 686 * Temporarily bump the current thread's td_nest_count to prevent deep 687 * preemptions and splz/doreti stacks. 688 */ 689 static __inline void ithread_fast_sched(int intr,thread_t td)690 ithread_fast_sched(int intr, thread_t td) 691 { 692 ++td->td_nest_count; 693 crit_exit_quick(td); 694 sched_ithd_hard(intr); 695 crit_enter_quick(td); 696 --td->td_nest_count; 697 } 698 699 /* 700 * This function is called directly from the ICU or APIC vector code assembly 701 * to process an interrupt. The critical section and interrupt deferral 702 * checks have already been done but the function is entered WITHOUT 703 * a critical section held. The BGL may or may not be held. 704 * 705 * Must return non-zero if we do not want the vector code to re-enable 706 * the interrupt (which we don't if we have to schedule the interrupt) 707 */ 708 int ithread_fast_handler(struct intrframe *frame); 709 710 int ithread_fast_handler(struct intrframe * frame)711 ithread_fast_handler(struct intrframe *frame) 712 { 713 int intr; 714 struct intr_info *info; 715 struct intrec **list; 716 int must_schedule; 717 int got_mplock; 718 TD_INVARIANTS_DECLARE; 719 intrec_t rec, nrec; 720 globaldata_t gd; 721 thread_t td; 722 723 intr = frame->if_vec; 724 gd = mycpu; 725 td = curthread; 726 727 /* We must be in critical section. */ 728 KKASSERT(td->td_critcount); 729 730 /* Race condition during early boot */ 731 if (intr_block == NULL) 732 return 0; 733 734 info = &intr_block->ary[mycpuid][intr]; 735 736 /* 737 * If we are not processing any FAST interrupts, just schedule the thing. 738 */ 739 if (info->i_fast == 0) { 740 ++gd->gd_cnt.v_intr; 741 ithread_fast_sched(intr, td); 742 return(1); 743 } 744 745 /* 746 * This should not normally occur since interrupts ought to be 747 * masked if the ithread has been scheduled or is running. 748 */ 749 if (info->i_running) 750 return(1); 751 752 /* 753 * Bump the interrupt nesting level to process any FAST interrupts. 754 * Obtain the MP lock as necessary. If the MP lock cannot be obtained, 755 * schedule the interrupt thread to deal with the issue instead. 756 * 757 * To reduce overhead, just leave the MP lock held once it has been 758 * obtained. 759 */ 760 ++gd->gd_intr_nesting_level; 761 ++gd->gd_cnt.v_intr; 762 must_schedule = info->i_slow; 763 got_mplock = 0; 764 765 TD_INVARIANTS_GET(td); 766 list = &info->i_reclist; 767 768 for (rec = *list; rec; rec = nrec) { 769 /* rec may be invalid after call */ 770 nrec = rec->next; 771 772 if (rec->intr_flags & INTR_CLOCK) { 773 if ((rec->intr_flags & INTR_MPSAFE) == 0 && got_mplock == 0) { 774 if (try_mplock() == 0) { 775 /* Couldn't get the MP lock; just schedule it. */ 776 must_schedule = 1; 777 break; 778 } 779 got_mplock = 1; 780 } 781 if (rec->serializer) { 782 must_schedule += lwkt_serialize_handler_try( 783 rec->serializer, rec->handler, 784 rec->argument, frame); 785 } else { 786 rec->handler(rec->argument, frame); 787 } 788 TD_INVARIANTS_TEST(td, rec->name); 789 } 790 } 791 792 /* 793 * Cleanup 794 */ 795 --gd->gd_intr_nesting_level; 796 if (got_mplock) 797 rel_mplock(); 798 799 /* 800 * If we had a problem, or mixed fast and slow interrupt handlers are 801 * registered, schedule the ithread to catch the missed records (it 802 * will just re-run all of them). A return value of 0 indicates that 803 * all handlers have been run and the interrupt can be re-enabled, and 804 * a non-zero return indicates that the interrupt thread controls 805 * re-enablement. 806 */ 807 if (must_schedule > 0) 808 ithread_fast_sched(intr, td); 809 else if (must_schedule == 0) 810 ++info->i_count; 811 return(must_schedule); 812 } 813 814 /* 815 * Interrupt threads run this as their main loop. 816 * 817 * The handler begins execution outside a critical section and no MP lock. 818 * 819 * The i_running state starts at 0. When an interrupt occurs, the hardware 820 * interrupt is disabled and sched_ithd_hard(). The HW interrupt remains 821 * disabled until all routines have run. We then call machintr_intr_enable() 822 * to reenable the HW interrupt and deschedule us until the next interrupt. 823 * 824 * We are responsible for atomically checking i_running. i_running for our 825 * irq is only set in the context of our cpu, so a critical section is a 826 * sufficient interlock. 827 */ 828 #define LIVELOCK_TIMEFRAME(freq) ((freq) >> 2) /* 1/4 second */ 829 830 static void ithread_handler(void * arg)831 ithread_handler(void *arg) 832 { 833 struct intr_info *info; 834 int use_limit; 835 uint32_t lseconds; 836 int intr, cpuid = mycpuid; 837 int mpheld; 838 struct intrec **list; 839 intrec_t rec, nrec; 840 globaldata_t gd; 841 struct systimer ill_timer; /* enforced freq. timer */ 842 u_int ill_count; /* interrupt livelock counter */ 843 int upper_limit; /* interrupt livelock upper limit */ 844 TD_INVARIANTS_DECLARE; 845 846 ill_count = 0; 847 intr = (int)(intptr_t)arg; 848 info = &intr_block->ary[cpuid][intr]; 849 list = &info->i_reclist; 850 851 /* 852 * The loop must be entered with one critical section held. The thread 853 * does not hold the mplock on startup. 854 */ 855 gd = mycpu; 856 lseconds = gd->gd_time_seconds; 857 crit_enter_gd(gd); 858 mpheld = 0; 859 860 for (;;) { 861 /* 862 * The chain is only considered MPSAFE if all its interrupt handlers 863 * are MPSAFE. However, if intr_mpsafe has been turned off we 864 * always operate with the BGL. 865 */ 866 if (info->i_mplock_required != mpheld) { 867 if (info->i_mplock_required) { 868 KKASSERT(mpheld == 0); 869 get_mplock(); 870 mpheld = 1; 871 } else { 872 KKASSERT(mpheld != 0); 873 rel_mplock(); 874 mpheld = 0; 875 } 876 } 877 878 TD_INVARIANTS_GET(gd->gd_curthread); 879 880 /* 881 * If an interrupt is pending, clear i_running and execute the 882 * handlers. Note that certain types of interrupts can re-trigger 883 * and set i_running again. 884 * 885 * Each handler is run in a critical section. Note that we run both 886 * FAST and SLOW designated service routines. 887 */ 888 if (info->i_running) { 889 ++ill_count; 890 info->i_running = 0; 891 892 if (*list == NULL) 893 report_stray_interrupt(info, "ithread_handler"); 894 895 for (rec = *list; rec; rec = nrec) { 896 /* rec may be invalid after call */ 897 nrec = rec->next; 898 if (rec->handler == NULL) { 899 kprintf("NULL HANDLER %s\n", rec->name); 900 } else 901 if (rec->serializer) { 902 lwkt_serialize_handler_call(rec->serializer, rec->handler, 903 rec->argument, NULL); 904 } else { 905 rec->handler(rec->argument, NULL); 906 } 907 TD_INVARIANTS_TEST(gd->gd_curthread, rec->name); 908 } 909 } 910 911 /* 912 * This is our interrupt hook to add rate randomness to the random 913 * number generator. 914 */ 915 if (info->i_random.sc_enabled > 0) 916 add_interrupt_randomness(intr); 917 918 /* 919 * Unmask the interrupt to allow it to trigger again. This only 920 * applies to certain types of interrupts (typ level interrupts). 921 * This can result in the interrupt retriggering, but the retrigger 922 * will not be processed until we cycle our critical section. 923 * 924 * Only unmask interrupts while handlers are installed. It is 925 * possible to hit a situation where no handlers are installed 926 * due to a device driver livelocking and then tearing down its 927 * interrupt on close (the parallel bus being a good example). 928 */ 929 if (intr < FIRST_SOFTINT && *list) 930 machintr_intr_enable(intr); 931 932 /* 933 * Do a quick exit/enter to catch any higher-priority interrupt 934 * sources, such as the statclock, so thread time accounting 935 * will still work. This may also cause an interrupt to re-trigger. 936 */ 937 crit_exit_gd(gd); 938 crit_enter_gd(gd); 939 940 /* 941 * LIVELOCK STATE MACHINE 942 */ 943 switch(info->i_state) { 944 case ISTATE_NORMAL: 945 /* 946 * Reset the count each second. 947 */ 948 if (lseconds != gd->gd_time_seconds) { 949 lseconds = gd->gd_time_seconds; 950 ill_count = 0; 951 } 952 953 /* 954 * If we did not exceed the frequency limit, we are done. 955 * If the interrupt has not retriggered we deschedule ourselves. 956 */ 957 if (info->i_flags & INTR_HIFREQ) 958 upper_limit = livelock_limit_hi; 959 else 960 upper_limit = livelock_limit; 961 if (ill_count <= upper_limit) { 962 if (info->i_running == 0) { 963 lwkt_deschedule_self(gd->gd_curthread); 964 lwkt_switch(); 965 } 966 break; 967 } 968 969 /* 970 * Otherwise we are livelocked. Set up a periodic systimer 971 * to wake the thread up at the limit frequency. 972 */ 973 kprintf("intr %d on cpu%d at %d/%d hz, livelocked limit engaged!\n", 974 intr, cpuid, ill_count, upper_limit); 975 info->i_state = ISTATE_LIVELOCKED; 976 if ((use_limit = upper_limit) < 100) 977 use_limit = 100; 978 else if (use_limit > 500000) 979 use_limit = 500000; 980 systimer_init_periodic_nq(&ill_timer, ithread_livelock_wakeup, 981 (void *)(intptr_t)intr, use_limit); 982 /* fall through */ 983 case ISTATE_LIVELOCKED: 984 /* 985 * Wait for our periodic timer to go off. Since the interrupt 986 * has re-armed it can still set i_running, but it will not 987 * reschedule us while we are in a livelocked state. 988 */ 989 lwkt_deschedule_self(gd->gd_curthread); 990 lwkt_switch(); 991 992 /* 993 * Check once a second to see if the livelock condition no 994 * longer applies. 995 */ 996 if (lseconds != gd->gd_time_seconds) { 997 lseconds = gd->gd_time_seconds; 998 if (ill_count < livelock_lowater) { 999 info->i_state = ISTATE_NORMAL; 1000 systimer_del(&ill_timer); 1001 kprintf("intr %d on cpu%d at %d/%d hz, livelock removed\n", 1002 intr, cpuid, ill_count, livelock_lowater); 1003 } else if (livelock_debug == intr || 1004 (bootverbose && cold)) { 1005 kprintf("intr %d on cpu%d at %d/%d hz, in livelock\n", 1006 intr, cpuid, ill_count, livelock_lowater); 1007 } 1008 ill_count = 0; 1009 } 1010 break; 1011 } 1012 } 1013 /* NOT REACHED */ 1014 } 1015 1016 /* 1017 * Emergency interrupt polling thread. The thread begins execution 1018 * outside a critical section with the BGL held. 1019 * 1020 * If emergency interrupt polling is enabled, this thread will 1021 * execute all system interrupts not marked INTR_NOPOLL at the 1022 * specified polling frequency. 1023 * 1024 * WARNING! This thread runs *ALL* interrupt service routines that 1025 * are not marked INTR_NOPOLL, which basically means everything except 1026 * the 8254 clock interrupt and the ATA interrupt. It has very high 1027 * overhead and should only be used in situations where the machine 1028 * cannot otherwise be made to work. Due to the severe performance 1029 * degredation, it should not be enabled on production machines. 1030 */ 1031 static void ithread_emergency(void * arg __unused)1032 ithread_emergency(void *arg __unused) 1033 { 1034 globaldata_t gd = mycpu; 1035 struct intr_info *info; 1036 intrec_t rec, nrec; 1037 int intr, cpuid = mycpuid; 1038 TD_INVARIANTS_DECLARE; 1039 1040 get_mplock(); 1041 crit_enter_gd(gd); 1042 TD_INVARIANTS_GET(gd->gd_curthread); 1043 1044 for (;;) { 1045 for (intr = 0; intr < max_installed_hard_intr[cpuid]; ++intr) { 1046 info = &intr_block->ary[cpuid][intr]; 1047 for (rec = info->i_reclist; rec; rec = nrec) { 1048 /* rec may be invalid after call */ 1049 nrec = rec->next; 1050 if ((rec->intr_flags & INTR_NOPOLL) == 0) { 1051 if (rec->serializer) { 1052 lwkt_serialize_handler_try(rec->serializer, 1053 rec->handler, rec->argument, NULL); 1054 } else { 1055 rec->handler(rec->argument, NULL); 1056 } 1057 TD_INVARIANTS_TEST(gd->gd_curthread, rec->name); 1058 } 1059 } 1060 } 1061 lwkt_deschedule_self(gd->gd_curthread); 1062 lwkt_switch(); 1063 } 1064 /* NOT REACHED */ 1065 } 1066 1067 /* 1068 * Systimer callback - schedule the emergency interrupt poll thread 1069 * if emergency polling is enabled. 1070 */ 1071 static 1072 void emergency_intr_timer_callback(systimer_t info,int in_ipi __unused,struct intrframe * frame __unused)1073 emergency_intr_timer_callback(systimer_t info, int in_ipi __unused, 1074 struct intrframe *frame __unused) 1075 { 1076 if (emergency_intr_enable) 1077 lwkt_schedule(info->data); 1078 } 1079 1080 /* 1081 * Sysctls used by systat and others: hw.intrnames and hw.intrcnt. 1082 * The data for this machine dependent, and the declarations are in machine 1083 * dependent code. The layout of intrnames and intrcnt however is machine 1084 * independent. 1085 * 1086 * We do not know the length of intrcnt and intrnames at compile time, so 1087 * calculate things at run time. 1088 */ 1089 1090 static int sysctl_intrnames(SYSCTL_HANDLER_ARGS)1091 sysctl_intrnames(SYSCTL_HANDLER_ARGS) 1092 { 1093 struct intr_info *info; 1094 intrec_t rec; 1095 int error = 0; 1096 int len; 1097 int intr, cpuid; 1098 char buf[64]; 1099 1100 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 1101 for (intr = 0; error == 0 && intr < MAX_INTS; ++intr) { 1102 info = &intr_block->ary[cpuid][intr]; 1103 1104 len = 0; 1105 buf[0] = 0; 1106 for (rec = info->i_reclist; rec; rec = rec->next) { 1107 ksnprintf(buf + len, sizeof(buf) - len, "%s%s", 1108 (len ? "/" : ""), rec->name); 1109 len += strlen(buf + len); 1110 } 1111 if (len == 0) { 1112 ksnprintf(buf, sizeof(buf), "irq%d", intr); 1113 len = strlen(buf); 1114 } 1115 error = SYSCTL_OUT(req, buf, len + 1); 1116 } 1117 } 1118 return (error); 1119 } 1120 1121 SYSCTL_PROC(_hw, OID_AUTO, intrnames, CTLTYPE_OPAQUE | CTLFLAG_RD, 1122 NULL, 0, sysctl_intrnames, "", "Interrupt Names"); 1123 1124 static int sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS)1125 sysctl_intrcnt_all(SYSCTL_HANDLER_ARGS) 1126 { 1127 struct intr_info *info; 1128 int error = 0; 1129 int intr, cpuid; 1130 1131 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 1132 for (intr = 0; intr < MAX_INTS; ++intr) { 1133 info = &intr_block->ary[cpuid][intr]; 1134 1135 error = SYSCTL_OUT(req, &info->i_count, sizeof(info->i_count)); 1136 if (error) 1137 goto failed; 1138 } 1139 } 1140 failed: 1141 return(error); 1142 } 1143 1144 SYSCTL_PROC(_hw, OID_AUTO, intrcnt_all, CTLTYPE_OPAQUE | CTLFLAG_RD, 1145 NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts"); 1146 1147 SYSCTL_PROC(_hw, OID_AUTO, intrcnt, CTLTYPE_OPAQUE | CTLFLAG_RD, 1148 NULL, 0, sysctl_intrcnt_all, "", "Interrupt Counts"); 1149 1150 static void int_moveto_destcpu(int * orig_cpuid0,int cpuid)1151 int_moveto_destcpu(int *orig_cpuid0, int cpuid) 1152 { 1153 int orig_cpuid = mycpuid; 1154 1155 if (cpuid != orig_cpuid) 1156 lwkt_migratecpu(cpuid); 1157 1158 *orig_cpuid0 = orig_cpuid; 1159 } 1160 1161 static void int_moveto_origcpu(int orig_cpuid,int cpuid)1162 int_moveto_origcpu(int orig_cpuid, int cpuid) 1163 { 1164 if (cpuid != orig_cpuid) 1165 lwkt_migratecpu(orig_cpuid); 1166 } 1167 1168 static void intr_init(void * dummy __unused)1169 intr_init(void *dummy __unused) 1170 { 1171 int cpuid; 1172 1173 kprintf("Initialize MI interrupts for %d cpus\n", ncpus); 1174 1175 intr_block = kmalloc(offsetof(struct intr_info_block, ary[ncpus][0]), 1176 M_INTRMNG, M_INTWAIT | M_ZERO); 1177 1178 for (cpuid = 0; cpuid < ncpus; ++cpuid) { 1179 int intr; 1180 1181 for (intr = 0; intr < MAX_INTS; ++intr) { 1182 struct intr_info *info = &intr_block->ary[cpuid][intr]; 1183 1184 info->i_cpuid = cpuid; 1185 info->i_intr = intr; 1186 } 1187 } 1188 } 1189 SYSINIT(intr_init, SI_BOOT2_FINISH_PIC, SI_ORDER_ANY, intr_init, NULL); 1190