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_sched.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/bus.h> 47 #include <sys/conf.h> 48 #include <sys/kdb.h> 49 #include <sys/kernel.h> 50 #include <sys/ktr.h> 51 #include <sys/lock.h> 52 #include <sys/malloc.h> 53 #include <sys/mutex.h> 54 #include <sys/proc.h> 55 #include <sys/resourcevar.h> 56 #include <sys/sched.h> 57 #include <sys/sbuf.h> 58 #include <sys/sysctl.h> 59 #include <sys/turnstile.h> 60 #include <sys/vmmeter.h> 61 #include <sys/lock_profile.h> 62 63 #include <machine/atomic.h> 64 #include <machine/bus.h> 65 #include <machine/cpu.h> 66 67 #include <ddb/ddb.h> 68 69 #include <fs/devfs/devfs_int.h> 70 71 #include <vm/vm.h> 72 #include <vm/vm_extern.h> 73 74 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 75 #define ADAPTIVE_MUTEXES 76 #endif 77 78 /* 79 * Internal utility macros. 80 */ 81 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) 82 83 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED) 84 85 #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK)) 86 87 static void assert_mtx(struct lock_object *lock, int what); 88 #ifdef DDB 89 static void db_show_mtx(struct lock_object *lock); 90 #endif 91 static void lock_mtx(struct lock_object *lock, int how); 92 static void lock_spin(struct lock_object *lock, int how); 93 static int unlock_mtx(struct lock_object *lock); 94 static int unlock_spin(struct lock_object *lock); 95 96 /* 97 * Lock classes for sleep and spin mutexes. 98 */ 99 struct lock_class lock_class_mtx_sleep = { 100 .lc_name = "sleep mutex", 101 .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, 102 .lc_assert = assert_mtx, 103 #ifdef DDB 104 .lc_ddb_show = db_show_mtx, 105 #endif 106 .lc_lock = lock_mtx, 107 .lc_unlock = unlock_mtx, 108 }; 109 struct lock_class lock_class_mtx_spin = { 110 .lc_name = "spin mutex", 111 .lc_flags = LC_SPINLOCK | LC_RECURSABLE, 112 .lc_assert = assert_mtx, 113 #ifdef DDB 114 .lc_ddb_show = db_show_mtx, 115 #endif 116 .lc_lock = lock_spin, 117 .lc_unlock = unlock_spin, 118 }; 119 120 /* 121 * System-wide mutexes 122 */ 123 struct mtx blocked_lock; 124 struct mtx Giant; 125 126 void 127 assert_mtx(struct lock_object *lock, int what) 128 { 129 130 mtx_assert((struct mtx *)lock, what); 131 } 132 133 void 134 lock_mtx(struct lock_object *lock, int how) 135 { 136 137 mtx_lock((struct mtx *)lock); 138 } 139 140 void 141 lock_spin(struct lock_object *lock, int how) 142 { 143 144 panic("spin locks can only use msleep_spin"); 145 } 146 147 int 148 unlock_mtx(struct lock_object *lock) 149 { 150 struct mtx *m; 151 152 m = (struct mtx *)lock; 153 mtx_assert(m, MA_OWNED | MA_NOTRECURSED); 154 mtx_unlock(m); 155 return (0); 156 } 157 158 int 159 unlock_spin(struct lock_object *lock) 160 { 161 162 panic("spin locks can only use msleep_spin"); 163 } 164 165 /* 166 * Function versions of the inlined __mtx_* macros. These are used by 167 * modules and can also be called from assembly language if needed. 168 */ 169 void 170 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line) 171 { 172 173 MPASS(curthread != NULL); 174 KASSERT(m->mtx_lock != MTX_DESTROYED, 175 ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); 176 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 177 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 178 file, line)); 179 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 180 file, line, NULL); 181 182 _get_sleep_lock(m, curthread, opts, file, line); 183 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 184 line); 185 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 186 curthread->td_locks++; 187 } 188 189 void 190 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line) 191 { 192 MPASS(curthread != NULL); 193 KASSERT(m->mtx_lock != MTX_DESTROYED, 194 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); 195 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 196 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 197 file, line)); 198 curthread->td_locks--; 199 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 200 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 201 line); 202 mtx_assert(m, MA_OWNED); 203 204 if (m->mtx_recurse == 0) 205 lock_profile_release_lock(&m->lock_object); 206 _rel_sleep_lock(m, curthread, opts, file, line); 207 } 208 209 void 210 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line) 211 { 212 213 MPASS(curthread != NULL); 214 KASSERT(m->mtx_lock != MTX_DESTROYED, 215 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); 216 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 217 ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 218 m->lock_object.lo_name, file, line)); 219 if (mtx_owned(m)) 220 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 221 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n", 222 m->lock_object.lo_name, file, line)); 223 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 224 file, line, NULL); 225 _get_spin_lock(m, curthread, opts, file, line); 226 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 227 line); 228 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 229 } 230 231 void 232 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line) 233 { 234 235 MPASS(curthread != NULL); 236 KASSERT(m->mtx_lock != MTX_DESTROYED, 237 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); 238 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 239 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 240 m->lock_object.lo_name, file, line)); 241 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 242 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 243 line); 244 mtx_assert(m, MA_OWNED); 245 246 _rel_spin_lock(m); 247 } 248 249 /* 250 * The important part of mtx_trylock{,_flags}() 251 * Tries to acquire lock `m.' If this function is called on a mutex that 252 * is already owned, it will recursively acquire the lock. 253 */ 254 int 255 _mtx_trylock(struct mtx *m, int opts, const char *file, int line) 256 { 257 #ifdef LOCK_PROFILING 258 uint64_t waittime = 0; 259 int contested = 0; 260 #endif 261 int rval; 262 263 MPASS(curthread != NULL); 264 KASSERT(m->mtx_lock != MTX_DESTROYED, 265 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); 266 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 267 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 268 file, line)); 269 270 if (mtx_owned(m) && (m->lock_object.lo_flags & LO_RECURSABLE) != 0) { 271 m->mtx_recurse++; 272 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 273 rval = 1; 274 } else 275 rval = _obtain_lock(m, (uintptr_t)curthread); 276 277 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line); 278 if (rval) { 279 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 280 file, line); 281 curthread->td_locks++; 282 if (m->mtx_recurse == 0) 283 lock_profile_obtain_lock_success(&m->lock_object, contested, 284 waittime, file, line); 285 286 } 287 288 return (rval); 289 } 290 291 /* 292 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 293 * 294 * We call this if the lock is either contested (i.e. we need to go to 295 * sleep waiting for it), or if we need to recurse on it. 296 */ 297 void 298 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, 299 int line) 300 { 301 struct turnstile *ts; 302 uintptr_t v; 303 #ifdef ADAPTIVE_MUTEXES 304 volatile struct thread *owner; 305 #endif 306 #ifdef KTR 307 int cont_logged = 0; 308 #endif 309 #ifdef LOCK_PROFILING 310 int contested = 0; 311 uint64_t waittime = 0; 312 #endif 313 314 if (mtx_owned(m)) { 315 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 316 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 317 m->lock_object.lo_name, file, line)); 318 m->mtx_recurse++; 319 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 320 if (LOCK_LOG_TEST(&m->lock_object, opts)) 321 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 322 return; 323 } 324 325 lock_profile_obtain_lock_failed(&m->lock_object, 326 &contested, &waittime); 327 if (LOCK_LOG_TEST(&m->lock_object, opts)) 328 CTR4(KTR_LOCK, 329 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 330 m->lock_object.lo_name, (void *)m->mtx_lock, file, line); 331 332 while (!_obtain_lock(m, tid)) { 333 #ifdef ADAPTIVE_MUTEXES 334 /* 335 * If the owner is running on another CPU, spin until the 336 * owner stops running or the state of the lock changes. 337 */ 338 v = m->mtx_lock; 339 if (v != MTX_UNOWNED) { 340 owner = (struct thread *)(v & ~MTX_FLAGMASK); 341 if (TD_IS_RUNNING(owner)) { 342 if (LOCK_LOG_TEST(&m->lock_object, 0)) 343 CTR3(KTR_LOCK, 344 "%s: spinning on %p held by %p", 345 __func__, m, owner); 346 while (mtx_owner(m) == owner && 347 TD_IS_RUNNING(owner)) 348 cpu_spinwait(); 349 continue; 350 } 351 } 352 #endif 353 354 ts = turnstile_trywait(&m->lock_object); 355 v = m->mtx_lock; 356 357 /* 358 * Check if the lock has been released while spinning for 359 * the turnstile chain lock. 360 */ 361 if (v == MTX_UNOWNED) { 362 turnstile_cancel(ts); 363 cpu_spinwait(); 364 continue; 365 } 366 367 MPASS(v != MTX_CONTESTED); 368 369 #ifdef ADAPTIVE_MUTEXES 370 /* 371 * If the current owner of the lock is executing on another 372 * CPU quit the hard path and try to spin. 373 */ 374 owner = (struct thread *)(v & ~MTX_FLAGMASK); 375 if (TD_IS_RUNNING(owner)) { 376 turnstile_cancel(ts); 377 cpu_spinwait(); 378 continue; 379 } 380 #endif 381 382 /* 383 * If the mutex isn't already contested and a failure occurs 384 * setting the contested bit, the mutex was either released 385 * or the state of the MTX_RECURSED bit changed. 386 */ 387 if ((v & MTX_CONTESTED) == 0 && 388 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) { 389 turnstile_cancel(ts); 390 cpu_spinwait(); 391 continue; 392 } 393 394 /* 395 * We definitely must sleep for this lock. 396 */ 397 mtx_assert(m, MA_NOTOWNED); 398 399 #ifdef KTR 400 if (!cont_logged) { 401 CTR6(KTR_CONTENTION, 402 "contention: %p at %s:%d wants %s, taken by %s:%d", 403 (void *)tid, file, line, m->lock_object.lo_name, 404 WITNESS_FILE(&m->lock_object), 405 WITNESS_LINE(&m->lock_object)); 406 cont_logged = 1; 407 } 408 #endif 409 410 /* 411 * Block on the turnstile. 412 */ 413 turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE); 414 } 415 #ifdef KTR 416 if (cont_logged) { 417 CTR4(KTR_CONTENTION, 418 "contention end: %s acquired by %p at %s:%d", 419 m->lock_object.lo_name, (void *)tid, file, line); 420 } 421 #endif 422 lock_profile_obtain_lock_success(&m->lock_object, contested, 423 waittime, file, line); 424 } 425 426 static void 427 _mtx_lock_spin_failed(struct mtx *m) 428 { 429 struct thread *td; 430 431 td = mtx_owner(m); 432 433 /* If the mutex is unlocked, try again. */ 434 if (td == NULL) 435 return; 436 437 printf( "spin lock %p (%s) held by %p (tid %d) too long\n", 438 m, m->lock_object.lo_name, td, td->td_tid); 439 #ifdef WITNESS 440 witness_display_spinlock(&m->lock_object, td); 441 #endif 442 panic("spin lock held too long"); 443 } 444 445 #ifdef SMP 446 /* 447 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. 448 * 449 * This is only called if we need to actually spin for the lock. Recursion 450 * is handled inline. 451 */ 452 void 453 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file, 454 int line) 455 { 456 int i = 0; 457 #ifdef LOCK_PROFILING 458 int contested = 0; 459 uint64_t waittime = 0; 460 #endif 461 462 if (LOCK_LOG_TEST(&m->lock_object, opts)) 463 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 464 465 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); 466 while (!_obtain_lock(m, tid)) { 467 468 /* Give interrupts a chance while we spin. */ 469 spinlock_exit(); 470 while (m->mtx_lock != MTX_UNOWNED) { 471 if (i++ < 10000000) { 472 cpu_spinwait(); 473 continue; 474 } 475 if (i < 60000000 || kdb_active || panicstr != NULL) 476 DELAY(1); 477 else 478 _mtx_lock_spin_failed(m); 479 cpu_spinwait(); 480 } 481 spinlock_enter(); 482 } 483 484 if (LOCK_LOG_TEST(&m->lock_object, opts)) 485 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 486 487 lock_profile_obtain_lock_success(&m->lock_object, contested, 488 waittime, (file), (line)); 489 } 490 #endif /* SMP */ 491 492 void 493 _thread_lock_flags(struct thread *td, int opts, const char *file, int line) 494 { 495 struct mtx *m; 496 uintptr_t tid; 497 int i; 498 #ifdef LOCK_PROFILING 499 int contested = 0; 500 uint64_t waittime = 0; 501 #endif 502 503 i = 0; 504 tid = (uintptr_t)curthread; 505 for (;;) { 506 retry: 507 spinlock_enter(); 508 m = td->td_lock; 509 KASSERT(m->mtx_lock != MTX_DESTROYED, 510 ("thread_lock() of destroyed mutex @ %s:%d", file, line)); 511 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 512 ("thread_lock() of sleep mutex %s @ %s:%d", 513 m->lock_object.lo_name, file, line)); 514 if (mtx_owned(m)) 515 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 516 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", 517 m->lock_object.lo_name, file, line)); 518 WITNESS_CHECKORDER(&m->lock_object, 519 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 520 while (!_obtain_lock(m, tid)) { 521 if (m->mtx_lock == tid) { 522 m->mtx_recurse++; 523 break; 524 } 525 lock_profile_obtain_lock_failed(&m->lock_object, 526 &contested, &waittime); 527 /* Give interrupts a chance while we spin. */ 528 spinlock_exit(); 529 while (m->mtx_lock != MTX_UNOWNED) { 530 if (i++ < 10000000) 531 cpu_spinwait(); 532 else if (i < 60000000 || 533 kdb_active || panicstr != NULL) 534 DELAY(1); 535 else 536 _mtx_lock_spin_failed(m); 537 cpu_spinwait(); 538 if (m != td->td_lock) 539 goto retry; 540 } 541 spinlock_enter(); 542 } 543 if (m == td->td_lock) 544 break; 545 _rel_spin_lock(m); /* does spinlock_exit() */ 546 } 547 if (m->mtx_recurse == 0) 548 lock_profile_obtain_lock_success(&m->lock_object, contested, 549 waittime, (file), (line)); 550 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 551 line); 552 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 553 } 554 555 struct mtx * 556 thread_lock_block(struct thread *td) 557 { 558 struct mtx *lock; 559 560 spinlock_enter(); 561 THREAD_LOCK_ASSERT(td, MA_OWNED); 562 lock = td->td_lock; 563 td->td_lock = &blocked_lock; 564 mtx_unlock_spin(lock); 565 566 return (lock); 567 } 568 569 void 570 thread_lock_unblock(struct thread *td, struct mtx *new) 571 { 572 mtx_assert(new, MA_OWNED); 573 MPASS(td->td_lock == &blocked_lock); 574 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); 575 spinlock_exit(); 576 } 577 578 void 579 thread_lock_set(struct thread *td, struct mtx *new) 580 { 581 struct mtx *lock; 582 583 mtx_assert(new, MA_OWNED); 584 THREAD_LOCK_ASSERT(td, MA_OWNED); 585 lock = td->td_lock; 586 td->td_lock = new; 587 mtx_unlock_spin(lock); 588 } 589 590 /* 591 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 592 * 593 * We are only called here if the lock is recursed or contested (i.e. we 594 * need to wake up a blocked thread). 595 */ 596 void 597 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) 598 { 599 struct turnstile *ts; 600 601 if (mtx_recursed(m)) { 602 if (--(m->mtx_recurse) == 0) 603 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 604 if (LOCK_LOG_TEST(&m->lock_object, opts)) 605 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 606 return; 607 } 608 609 /* 610 * We have to lock the chain before the turnstile so this turnstile 611 * can be removed from the hash list if it is empty. 612 */ 613 turnstile_chain_lock(&m->lock_object); 614 ts = turnstile_lookup(&m->lock_object); 615 if (LOCK_LOG_TEST(&m->lock_object, opts)) 616 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 617 MPASS(ts != NULL); 618 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 619 _release_lock_quick(m); 620 621 /* 622 * This turnstile is now no longer associated with the mutex. We can 623 * unlock the chain lock so a new turnstile may take it's place. 624 */ 625 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); 626 turnstile_chain_unlock(&m->lock_object); 627 } 628 629 /* 630 * All the unlocking of MTX_SPIN locks is done inline. 631 * See the _rel_spin_lock() macro for the details. 632 */ 633 634 /* 635 * The backing function for the INVARIANTS-enabled mtx_assert() 636 */ 637 #ifdef INVARIANT_SUPPORT 638 void 639 _mtx_assert(struct mtx *m, int what, const char *file, int line) 640 { 641 642 if (panicstr != NULL || dumping) 643 return; 644 switch (what) { 645 case MA_OWNED: 646 case MA_OWNED | MA_RECURSED: 647 case MA_OWNED | MA_NOTRECURSED: 648 if (!mtx_owned(m)) 649 panic("mutex %s not owned at %s:%d", 650 m->lock_object.lo_name, file, line); 651 if (mtx_recursed(m)) { 652 if ((what & MA_NOTRECURSED) != 0) 653 panic("mutex %s recursed at %s:%d", 654 m->lock_object.lo_name, file, line); 655 } else if ((what & MA_RECURSED) != 0) { 656 panic("mutex %s unrecursed at %s:%d", 657 m->lock_object.lo_name, file, line); 658 } 659 break; 660 case MA_NOTOWNED: 661 if (mtx_owned(m)) 662 panic("mutex %s owned at %s:%d", 663 m->lock_object.lo_name, file, line); 664 break; 665 default: 666 panic("unknown mtx_assert at %s:%d", file, line); 667 } 668 } 669 #endif 670 671 /* 672 * The MUTEX_DEBUG-enabled mtx_validate() 673 * 674 * Most of these checks have been moved off into the LO_INITIALIZED flag 675 * maintained by the witness code. 676 */ 677 #ifdef MUTEX_DEBUG 678 679 void mtx_validate(struct mtx *); 680 681 void 682 mtx_validate(struct mtx *m) 683 { 684 685 /* 686 * XXX: When kernacc() does not require Giant we can reenable this check 687 */ 688 #ifdef notyet 689 /* 690 * Can't call kernacc() from early init386(), especially when 691 * initializing Giant mutex, because some stuff in kernacc() 692 * requires Giant itself. 693 */ 694 if (!cold) 695 if (!kernacc((caddr_t)m, sizeof(m), 696 VM_PROT_READ | VM_PROT_WRITE)) 697 panic("Can't read and write to mutex %p", m); 698 #endif 699 } 700 #endif 701 702 /* 703 * General init routine used by the MTX_SYSINIT() macro. 704 */ 705 void 706 mtx_sysinit(void *arg) 707 { 708 struct mtx_args *margs = arg; 709 710 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); 711 } 712 713 /* 714 * Mutex initialization routine; initialize lock `m' of type contained in 715 * `opts' with options contained in `opts' and name `name.' The optional 716 * lock type `type' is used as a general lock category name for use with 717 * witness. 718 */ 719 void 720 mtx_init(struct mtx *m, const char *name, const char *type, int opts) 721 { 722 struct lock_class *class; 723 int flags; 724 725 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 726 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0); 727 728 #ifdef MUTEX_DEBUG 729 /* Diagnostic and error correction */ 730 mtx_validate(m); 731 #endif 732 733 /* Determine lock class and lock flags. */ 734 if (opts & MTX_SPIN) 735 class = &lock_class_mtx_spin; 736 else 737 class = &lock_class_mtx_sleep; 738 flags = 0; 739 if (opts & MTX_QUIET) 740 flags |= LO_QUIET; 741 if (opts & MTX_RECURSE) 742 flags |= LO_RECURSABLE; 743 if ((opts & MTX_NOWITNESS) == 0) 744 flags |= LO_WITNESS; 745 if (opts & MTX_DUPOK) 746 flags |= LO_DUPOK; 747 if (opts & MTX_NOPROFILE) 748 flags |= LO_NOPROFILE; 749 750 /* Initialize mutex. */ 751 m->mtx_lock = MTX_UNOWNED; 752 m->mtx_recurse = 0; 753 754 lock_init(&m->lock_object, class, name, type, flags); 755 } 756 757 /* 758 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 759 * passed in as a flag here because if the corresponding mtx_init() was 760 * called with MTX_QUIET set, then it will already be set in the mutex's 761 * flags. 762 */ 763 void 764 mtx_destroy(struct mtx *m) 765 { 766 767 if (!mtx_owned(m)) 768 MPASS(mtx_unowned(m)); 769 else { 770 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 771 772 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 773 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) 774 spinlock_exit(); 775 else 776 curthread->td_locks--; 777 778 lock_profile_release_lock(&m->lock_object); 779 /* Tell witness this isn't locked to make it happy. */ 780 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, 781 __LINE__); 782 } 783 784 m->mtx_lock = MTX_DESTROYED; 785 lock_destroy(&m->lock_object); 786 } 787 788 /* 789 * Intialize the mutex code and system mutexes. This is called from the MD 790 * startup code prior to mi_startup(). The per-CPU data space needs to be 791 * setup before this is called. 792 */ 793 void 794 mutex_init(void) 795 { 796 797 /* Setup turnstiles so that sleep mutexes work. */ 798 init_turnstiles(); 799 800 /* 801 * Initialize mutexes. 802 */ 803 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 804 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); 805 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ 806 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 807 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE); 808 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 809 mtx_lock(&Giant); 810 } 811 812 #ifdef DDB 813 void 814 db_show_mtx(struct lock_object *lock) 815 { 816 struct thread *td; 817 struct mtx *m; 818 819 m = (struct mtx *)lock; 820 821 db_printf(" flags: {"); 822 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 823 db_printf("SPIN"); 824 else 825 db_printf("DEF"); 826 if (m->lock_object.lo_flags & LO_RECURSABLE) 827 db_printf(", RECURSE"); 828 if (m->lock_object.lo_flags & LO_DUPOK) 829 db_printf(", DUPOK"); 830 db_printf("}\n"); 831 db_printf(" state: {"); 832 if (mtx_unowned(m)) 833 db_printf("UNOWNED"); 834 else if (mtx_destroyed(m)) 835 db_printf("DESTROYED"); 836 else { 837 db_printf("OWNED"); 838 if (m->mtx_lock & MTX_CONTESTED) 839 db_printf(", CONTESTED"); 840 if (m->mtx_lock & MTX_RECURSED) 841 db_printf(", RECURSED"); 842 } 843 db_printf("}\n"); 844 if (!mtx_unowned(m) && !mtx_destroyed(m)) { 845 td = mtx_owner(m); 846 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 847 td->td_tid, td->td_proc->p_pid, td->td_name); 848 if (mtx_recursed(m)) 849 db_printf(" recursed: %d\n", m->mtx_recurse); 850 } 851 } 852 #endif 853