1 /*- 2 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ 29 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ 30 */ 31 32 /* 33 * Machine independent bits of mutex implementation. 34 */ 35 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "opt_adaptive_mutexes.h" 40 #include "opt_ddb.h" 41 #include "opt_global.h" 42 #include "opt_mutex_wake_all.h" 43 #include "opt_sched.h" 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/bus.h> 48 #include <sys/conf.h> 49 #include <sys/kdb.h> 50 #include <sys/kernel.h> 51 #include <sys/ktr.h> 52 #include <sys/lock.h> 53 #include <sys/malloc.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sched.h> 58 #include <sys/sbuf.h> 59 #include <sys/sysctl.h> 60 #include <sys/turnstile.h> 61 #include <sys/vmmeter.h> 62 #include <sys/lock_profile.h> 63 64 #include <machine/atomic.h> 65 #include <machine/bus.h> 66 #include <machine/cpu.h> 67 68 #include <ddb/ddb.h> 69 70 #include <fs/devfs/devfs_int.h> 71 72 #include <vm/vm.h> 73 #include <vm/vm_extern.h> 74 75 /* 76 * Force MUTEX_WAKE_ALL for now. 77 * single thread wakeup needs fixes to avoid race conditions with 78 * priority inheritance. 79 */ 80 #ifndef MUTEX_WAKE_ALL 81 #define MUTEX_WAKE_ALL 82 #endif 83 84 /* 85 * Internal utility macros. 86 */ 87 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) 88 89 #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK)) 90 91 #ifdef DDB 92 static void db_show_mtx(struct lock_object *lock); 93 #endif 94 95 /* 96 * Lock classes for sleep and spin mutexes. 97 */ 98 struct lock_class lock_class_mtx_sleep = { 99 "sleep mutex", 100 LC_SLEEPLOCK | LC_RECURSABLE, 101 #ifdef DDB 102 db_show_mtx 103 #endif 104 }; 105 struct lock_class lock_class_mtx_spin = { 106 "spin mutex", 107 LC_SPINLOCK | LC_RECURSABLE, 108 #ifdef DDB 109 db_show_mtx 110 #endif 111 }; 112 113 /* 114 * System-wide mutexes 115 */ 116 struct mtx sched_lock; 117 struct mtx Giant; 118 119 #ifdef LOCK_PROFILING 120 static inline void lock_profile_init(void) 121 { 122 int i; 123 /* Initialize the mutex profiling locks */ 124 for (i = 0; i < LPROF_LOCK_SIZE; i++) { 125 mtx_init(&lprof_locks[i], "mprof lock", 126 NULL, MTX_SPIN|MTX_QUIET|MTX_NOPROFILE); 127 } 128 } 129 #else 130 static inline void lock_profile_init(void) {;} 131 #endif 132 133 /* 134 * Function versions of the inlined __mtx_* macros. These are used by 135 * modules and can also be called from assembly language if needed. 136 */ 137 void 138 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line) 139 { 140 141 MPASS(curthread != NULL); 142 KASSERT(m->mtx_lock != MTX_DESTROYED, 143 ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); 144 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 145 ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 146 file, line)); 147 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 148 file, line); 149 150 _get_sleep_lock(m, curthread, opts, file, line); 151 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 152 line); 153 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 154 curthread->td_locks++; 155 } 156 157 void 158 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line) 159 { 160 #ifdef LOCK_PROFILING 161 struct lock_object lo; 162 #endif 163 MPASS(curthread != NULL); 164 KASSERT(m->mtx_lock != MTX_DESTROYED, 165 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); 166 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 167 ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 168 file, line)); 169 curthread->td_locks--; 170 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 171 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 172 line); 173 mtx_assert(m, MA_OWNED); 174 #ifdef LOCK_PROFILING 175 memcpy(&lo, &m->mtx_object, sizeof(lo)); 176 m->mtx_object.lo_flags &= ~LO_CONTESTED; 177 #endif 178 _rel_sleep_lock(m, curthread, opts, file, line); 179 #ifdef LOCK_PROFILING 180 lock_profile_release_lock(&lo); 181 #endif 182 } 183 184 void 185 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line) 186 { 187 188 MPASS(curthread != NULL); 189 KASSERT(m->mtx_lock != MTX_DESTROYED, 190 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); 191 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin, 192 ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 193 m->mtx_object.lo_name, file, line)); 194 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 195 file, line); 196 _get_spin_lock(m, curthread, opts, file, line); 197 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 198 line); 199 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 200 } 201 202 void 203 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line) 204 { 205 #ifdef LOCK_PROFILING 206 struct lock_object lo; 207 #endif 208 MPASS(curthread != NULL); 209 KASSERT(m->mtx_lock != MTX_DESTROYED, 210 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); 211 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin, 212 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 213 m->mtx_object.lo_name, file, line)); 214 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 215 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 216 line); 217 mtx_assert(m, MA_OWNED); 218 #ifdef LOCK_PROFILING 219 memcpy(&lo, &m->mtx_object, sizeof(lo)); 220 m->mtx_object.lo_flags &= ~LO_CONTESTED; 221 #endif 222 _rel_spin_lock(m); 223 #ifdef LOCK_PROFILING 224 lock_profile_release_lock(&lo); 225 #endif 226 } 227 228 /* 229 * The important part of mtx_trylock{,_flags}() 230 * Tries to acquire lock `m.' If this function is called on a mutex that 231 * is already owned, it will recursively acquire the lock. 232 */ 233 int 234 _mtx_trylock(struct mtx *m, int opts, const char *file, int line) 235 { 236 int rval, contested = 0; 237 uint64_t waittime = 0; 238 239 MPASS(curthread != NULL); 240 KASSERT(m->mtx_lock != MTX_DESTROYED, 241 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); 242 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 243 ("mtx_trylock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 244 file, line)); 245 246 if (mtx_owned(m) && (m->mtx_object.lo_flags & LO_RECURSABLE) != 0) { 247 m->mtx_recurse++; 248 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 249 rval = 1; 250 } else 251 rval = _obtain_lock(m, (uintptr_t)curthread); 252 253 LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line); 254 if (rval) { 255 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 256 file, line); 257 curthread->td_locks++; 258 if (m->mtx_recurse == 0) 259 lock_profile_obtain_lock_success(&m->mtx_object, contested, 260 waittime, file, line); 261 262 } 263 264 return (rval); 265 } 266 267 /* 268 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 269 * 270 * We call this if the lock is either contested (i.e. we need to go to 271 * sleep waiting for it), or if we need to recurse on it. 272 */ 273 void 274 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, 275 int line) 276 { 277 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 278 volatile struct thread *owner; 279 #endif 280 #ifdef KTR 281 int cont_logged = 0; 282 #endif 283 uintptr_t v; 284 285 if (mtx_owned(m)) { 286 KASSERT((m->mtx_object.lo_flags & LO_RECURSABLE) != 0, 287 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 288 m->mtx_object.lo_name, file, line)); 289 m->mtx_recurse++; 290 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 291 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 292 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 293 return; 294 } 295 296 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 297 CTR4(KTR_LOCK, 298 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 299 m->mtx_object.lo_name, (void *)m->mtx_lock, file, line); 300 301 while (!_obtain_lock(m, tid)) { 302 turnstile_lock(&m->mtx_object); 303 v = m->mtx_lock; 304 305 /* 306 * Check if the lock has been released while spinning for 307 * the turnstile chain lock. 308 */ 309 if (v == MTX_UNOWNED) { 310 turnstile_release(&m->mtx_object); 311 cpu_spinwait(); 312 continue; 313 } 314 315 #ifdef MUTEX_WAKE_ALL 316 MPASS(v != MTX_CONTESTED); 317 #else 318 /* 319 * The mutex was marked contested on release. This means that 320 * there are other threads blocked on it. Grab ownership of 321 * it and propagate its priority to the current thread if 322 * necessary. 323 */ 324 if (v == MTX_CONTESTED) { 325 m->mtx_lock = tid | MTX_CONTESTED; 326 turnstile_claim(&m->mtx_object); 327 break; 328 } 329 #endif 330 331 /* 332 * If the mutex isn't already contested and a failure occurs 333 * setting the contested bit, the mutex was either released 334 * or the state of the MTX_RECURSED bit changed. 335 */ 336 if ((v & MTX_CONTESTED) == 0 && 337 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) { 338 turnstile_release(&m->mtx_object); 339 cpu_spinwait(); 340 continue; 341 } 342 343 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 344 /* 345 * If the current owner of the lock is executing on another 346 * CPU, spin instead of blocking. 347 */ 348 owner = (struct thread *)(v & ~MTX_FLAGMASK); 349 #ifdef ADAPTIVE_GIANT 350 if (TD_IS_RUNNING(owner)) 351 #else 352 if (m != &Giant && TD_IS_RUNNING(owner)) 353 #endif 354 { 355 turnstile_release(&m->mtx_object); 356 while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) { 357 cpu_spinwait(); 358 } 359 continue; 360 } 361 #endif /* SMP && !NO_ADAPTIVE_MUTEXES */ 362 363 /* 364 * We definitely must sleep for this lock. 365 */ 366 mtx_assert(m, MA_NOTOWNED); 367 368 #ifdef KTR 369 if (!cont_logged) { 370 CTR6(KTR_CONTENTION, 371 "contention: %p at %s:%d wants %s, taken by %s:%d", 372 (void *)tid, file, line, m->mtx_object.lo_name, 373 WITNESS_FILE(&m->mtx_object), 374 WITNESS_LINE(&m->mtx_object)); 375 cont_logged = 1; 376 } 377 #endif 378 379 /* 380 * Block on the turnstile. 381 */ 382 turnstile_wait(&m->mtx_object, mtx_owner(m), 383 TS_EXCLUSIVE_QUEUE); 384 } 385 #ifdef KTR 386 if (cont_logged) { 387 CTR4(KTR_CONTENTION, 388 "contention end: %s acquired by %p at %s:%d", 389 m->mtx_object.lo_name, (void *)tid, file, line); 390 } 391 #endif 392 return; 393 } 394 395 #ifdef SMP 396 /* 397 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. 398 * 399 * This is only called if we need to actually spin for the lock. Recursion 400 * is handled inline. 401 */ 402 void 403 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file, 404 int line) 405 { 406 int i = 0; 407 struct thread *td; 408 409 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 410 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 411 412 while (!_obtain_lock(m, tid)) { 413 414 /* Give interrupts a chance while we spin. */ 415 spinlock_exit(); 416 while (m->mtx_lock != MTX_UNOWNED) { 417 if (i++ < 10000000) { 418 cpu_spinwait(); 419 continue; 420 } 421 if (i < 60000000 || kdb_active || panicstr != NULL) 422 DELAY(1); 423 else { 424 td = mtx_owner(m); 425 426 /* If the mutex is unlocked, try again. */ 427 if (td == NULL) 428 continue; 429 printf( 430 "spin lock %p (%s) held by %p (tid %d) too long\n", 431 m, m->mtx_object.lo_name, td, td->td_tid); 432 #ifdef WITNESS 433 witness_display_spinlock(&m->mtx_object, td); 434 #endif 435 panic("spin lock held too long"); 436 } 437 cpu_spinwait(); 438 } 439 spinlock_enter(); 440 } 441 442 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 443 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 444 445 return; 446 } 447 #endif /* SMP */ 448 449 /* 450 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 451 * 452 * We are only called here if the lock is recursed or contested (i.e. we 453 * need to wake up a blocked thread). 454 */ 455 void 456 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) 457 { 458 struct turnstile *ts; 459 #ifndef PREEMPTION 460 struct thread *td, *td1; 461 #endif 462 463 if (mtx_recursed(m)) { 464 if (--(m->mtx_recurse) == 0) 465 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 466 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 467 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 468 return; 469 } 470 471 turnstile_lock(&m->mtx_object); 472 ts = turnstile_lookup(&m->mtx_object); 473 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 474 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 475 476 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 477 if (ts == NULL) { 478 _release_lock_quick(m); 479 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 480 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m); 481 turnstile_release(&m->mtx_object); 482 return; 483 } 484 #else 485 MPASS(ts != NULL); 486 #endif 487 #ifndef PREEMPTION 488 /* XXX */ 489 td1 = turnstile_head(ts, TS_EXCLUSIVE_QUEUE); 490 #endif 491 #ifdef MUTEX_WAKE_ALL 492 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 493 _release_lock_quick(m); 494 #else 495 if (turnstile_signal(ts, TS_EXCLUSIVE_QUEUE)) { 496 _release_lock_quick(m); 497 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 498 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m); 499 } else { 500 m->mtx_lock = MTX_CONTESTED; 501 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 502 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p still contested", 503 m); 504 } 505 #endif 506 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); 507 508 #ifndef PREEMPTION 509 /* 510 * XXX: This is just a hack until preemption is done. However, 511 * once preemption is done we need to either wrap the 512 * turnstile_signal() and release of the actual lock in an 513 * extra critical section or change the preemption code to 514 * always just set a flag and never do instant-preempts. 515 */ 516 td = curthread; 517 if (td->td_critnest > 0 || td1->td_priority >= td->td_priority) 518 return; 519 mtx_lock_spin(&sched_lock); 520 if (!TD_IS_RUNNING(td1)) { 521 #ifdef notyet 522 if (td->td_ithd != NULL) { 523 struct ithd *it = td->td_ithd; 524 525 if (it->it_interrupted) { 526 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 527 CTR2(KTR_LOCK, 528 "_mtx_unlock_sleep: %p interrupted %p", 529 it, it->it_interrupted); 530 intr_thd_fixup(it); 531 } 532 } 533 #endif 534 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 535 CTR2(KTR_LOCK, 536 "_mtx_unlock_sleep: %p switching out lock=%p", m, 537 (void *)m->mtx_lock); 538 539 mi_switch(SW_INVOL, NULL); 540 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 541 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p", 542 m, (void *)m->mtx_lock); 543 } 544 mtx_unlock_spin(&sched_lock); 545 #endif 546 547 return; 548 } 549 550 /* 551 * All the unlocking of MTX_SPIN locks is done inline. 552 * See the _rel_spin_lock() macro for the details. 553 */ 554 555 /* 556 * The backing function for the INVARIANTS-enabled mtx_assert() 557 */ 558 #ifdef INVARIANT_SUPPORT 559 void 560 _mtx_assert(struct mtx *m, int what, const char *file, int line) 561 { 562 563 if (panicstr != NULL || dumping) 564 return; 565 switch (what) { 566 case MA_OWNED: 567 case MA_OWNED | MA_RECURSED: 568 case MA_OWNED | MA_NOTRECURSED: 569 if (!mtx_owned(m)) 570 panic("mutex %s not owned at %s:%d", 571 m->mtx_object.lo_name, file, line); 572 if (mtx_recursed(m)) { 573 if ((what & MA_NOTRECURSED) != 0) 574 panic("mutex %s recursed at %s:%d", 575 m->mtx_object.lo_name, file, line); 576 } else if ((what & MA_RECURSED) != 0) { 577 panic("mutex %s unrecursed at %s:%d", 578 m->mtx_object.lo_name, file, line); 579 } 580 break; 581 case MA_NOTOWNED: 582 if (mtx_owned(m)) 583 panic("mutex %s owned at %s:%d", 584 m->mtx_object.lo_name, file, line); 585 break; 586 default: 587 panic("unknown mtx_assert at %s:%d", file, line); 588 } 589 } 590 #endif 591 592 /* 593 * The MUTEX_DEBUG-enabled mtx_validate() 594 * 595 * Most of these checks have been moved off into the LO_INITIALIZED flag 596 * maintained by the witness code. 597 */ 598 #ifdef MUTEX_DEBUG 599 600 void mtx_validate(struct mtx *); 601 602 void 603 mtx_validate(struct mtx *m) 604 { 605 606 /* 607 * XXX: When kernacc() does not require Giant we can reenable this check 608 */ 609 #ifdef notyet 610 /* 611 * Can't call kernacc() from early init386(), especially when 612 * initializing Giant mutex, because some stuff in kernacc() 613 * requires Giant itself. 614 */ 615 if (!cold) 616 if (!kernacc((caddr_t)m, sizeof(m), 617 VM_PROT_READ | VM_PROT_WRITE)) 618 panic("Can't read and write to mutex %p", m); 619 #endif 620 } 621 #endif 622 623 /* 624 * General init routine used by the MTX_SYSINIT() macro. 625 */ 626 void 627 mtx_sysinit(void *arg) 628 { 629 struct mtx_args *margs = arg; 630 631 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); 632 } 633 634 /* 635 * Mutex initialization routine; initialize lock `m' of type contained in 636 * `opts' with options contained in `opts' and name `name.' The optional 637 * lock type `type' is used as a general lock category name for use with 638 * witness. 639 */ 640 void 641 mtx_init(struct mtx *m, const char *name, const char *type, int opts) 642 { 643 struct lock_class *class; 644 int flags; 645 646 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 647 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0); 648 649 #ifdef MUTEX_DEBUG 650 /* Diagnostic and error correction */ 651 mtx_validate(m); 652 #endif 653 654 /* Determine lock class and lock flags. */ 655 if (opts & MTX_SPIN) 656 class = &lock_class_mtx_spin; 657 else 658 class = &lock_class_mtx_sleep; 659 flags = 0; 660 if (opts & MTX_QUIET) 661 flags |= LO_QUIET; 662 if (opts & MTX_RECURSE) 663 flags |= LO_RECURSABLE; 664 if ((opts & MTX_NOWITNESS) == 0) 665 flags |= LO_WITNESS; 666 if (opts & MTX_DUPOK) 667 flags |= LO_DUPOK; 668 if (opts & MTX_NOPROFILE) 669 flags |= LO_NOPROFILE; 670 671 /* Initialize mutex. */ 672 m->mtx_lock = MTX_UNOWNED; 673 m->mtx_recurse = 0; 674 675 lock_profile_object_init(&m->mtx_object, class, name); 676 lock_init(&m->mtx_object, class, name, type, flags); 677 } 678 679 /* 680 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 681 * passed in as a flag here because if the corresponding mtx_init() was 682 * called with MTX_QUIET set, then it will already be set in the mutex's 683 * flags. 684 */ 685 void 686 mtx_destroy(struct mtx *m) 687 { 688 689 if (!mtx_owned(m)) 690 MPASS(mtx_unowned(m)); 691 else { 692 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 693 694 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 695 if (LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin) 696 spinlock_exit(); 697 else 698 curthread->td_locks--; 699 700 /* Tell witness this isn't locked to make it happy. */ 701 WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__, 702 __LINE__); 703 } 704 705 m->mtx_lock = MTX_DESTROYED; 706 lock_profile_object_destroy(&m->mtx_object); 707 lock_destroy(&m->mtx_object); 708 } 709 710 /* 711 * Intialize the mutex code and system mutexes. This is called from the MD 712 * startup code prior to mi_startup(). The per-CPU data space needs to be 713 * setup before this is called. 714 */ 715 void 716 mutex_init(void) 717 { 718 719 /* Setup turnstiles so that sleep mutexes work. */ 720 init_turnstiles(); 721 722 /* 723 * Initialize mutexes. 724 */ 725 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 726 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE); 727 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 728 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 729 mtx_lock(&Giant); 730 731 lock_profile_init(); 732 } 733 734 #ifdef DDB 735 void 736 db_show_mtx(struct lock_object *lock) 737 { 738 struct thread *td; 739 struct mtx *m; 740 741 m = (struct mtx *)lock; 742 743 db_printf(" flags: {"); 744 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 745 db_printf("SPIN"); 746 else 747 db_printf("DEF"); 748 if (m->mtx_object.lo_flags & LO_RECURSABLE) 749 db_printf(", RECURSE"); 750 if (m->mtx_object.lo_flags & LO_DUPOK) 751 db_printf(", DUPOK"); 752 db_printf("}\n"); 753 db_printf(" state: {"); 754 if (mtx_unowned(m)) 755 db_printf("UNOWNED"); 756 else { 757 db_printf("OWNED"); 758 if (m->mtx_lock & MTX_CONTESTED) 759 db_printf(", CONTESTED"); 760 if (m->mtx_lock & MTX_RECURSED) 761 db_printf(", RECURSED"); 762 } 763 db_printf("}\n"); 764 if (!mtx_unowned(m)) { 765 td = mtx_owner(m); 766 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 767 td->td_tid, td->td_proc->p_pid, td->td_proc->p_comm); 768 if (mtx_recursed(m)) 769 db_printf(" recursed: %d\n", m->mtx_recurse); 770 } 771 } 772 #endif 773