1 /* $OpenBSD: kern_synch.c,v 1.187 2022/05/13 15:32:00 claudio Exp $ */ 2 /* $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1990, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)kern_synch.c 8.6 (Berkeley) 1/21/94 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/proc.h> 43 #include <sys/kernel.h> 44 #include <sys/signalvar.h> 45 #include <sys/resourcevar.h> 46 #include <sys/sched.h> 47 #include <sys/timeout.h> 48 #include <sys/mount.h> 49 #include <sys/syscallargs.h> 50 #include <sys/pool.h> 51 #include <sys/refcnt.h> 52 #include <sys/atomic.h> 53 #include <sys/witness.h> 54 #include <sys/tracepoint.h> 55 56 #include <ddb/db_output.h> 57 58 #include <machine/spinlock.h> 59 60 #ifdef DIAGNOSTIC 61 #include <sys/syslog.h> 62 #endif 63 64 #ifdef KTRACE 65 #include <sys/ktrace.h> 66 #endif 67 68 int sleep_signal_check(void); 69 int thrsleep(struct proc *, struct sys___thrsleep_args *); 70 int thrsleep_unlock(void *); 71 72 /* 73 * We're only looking at 7 bits of the address; everything is 74 * aligned to 4, lots of things are aligned to greater powers 75 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 76 */ 77 #define TABLESIZE 128 78 #define LOOKUP(x) (((long)(x) >> 8) & (TABLESIZE - 1)) 79 TAILQ_HEAD(slpque,proc) slpque[TABLESIZE]; 80 81 void 82 sleep_queue_init(void) 83 { 84 int i; 85 86 for (i = 0; i < TABLESIZE; i++) 87 TAILQ_INIT(&slpque[i]); 88 } 89 90 /* 91 * Global sleep channel for threads that do not want to 92 * receive wakeup(9) broadcasts. 93 */ 94 int nowake; 95 96 /* 97 * During autoconfiguration or after a panic, a sleep will simply 98 * lower the priority briefly to allow interrupts, then return. 99 * The priority to be used (safepri) is machine-dependent, thus this 100 * value is initialized and maintained in the machine-dependent layers. 101 * This priority will typically be 0, or the lowest priority 102 * that is safe for use on the interrupt stack; it can be made 103 * higher to block network software interrupts after panics. 104 */ 105 extern int safepri; 106 107 /* 108 * General sleep call. Suspends the current process until a wakeup is 109 * performed on the specified identifier. The process will then be made 110 * runnable with the specified priority. Sleeps at most timo/hz seconds 111 * (0 means no timeout). If pri includes PCATCH flag, signals are checked 112 * before and after sleeping, else signals are not checked. Returns 0 if 113 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 114 * signal needs to be delivered, ERESTART is returned if the current system 115 * call should be restarted if possible, and EINTR is returned if the system 116 * call should be interrupted by the signal (return EINTR). 117 */ 118 int 119 tsleep(const volatile void *ident, int priority, const char *wmesg, int timo) 120 { 121 struct sleep_state sls; 122 #ifdef MULTIPROCESSOR 123 int hold_count; 124 #endif 125 126 KASSERT((priority & ~(PRIMASK | PCATCH)) == 0); 127 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 128 129 #ifdef MULTIPROCESSOR 130 KASSERT(timo || _kernel_lock_held()); 131 #endif 132 133 #ifdef DDB 134 if (cold == 2) 135 db_stack_dump(); 136 #endif 137 if (cold || panicstr) { 138 int s; 139 /* 140 * After a panic, or during autoconfiguration, 141 * just give interrupts a chance, then just return; 142 * don't run any other procs or panic below, 143 * in case this is the idle process and already asleep. 144 */ 145 s = splhigh(); 146 splx(safepri); 147 #ifdef MULTIPROCESSOR 148 if (_kernel_lock_held()) { 149 hold_count = __mp_release_all(&kernel_lock); 150 __mp_acquire_count(&kernel_lock, hold_count); 151 } 152 #endif 153 splx(s); 154 return (0); 155 } 156 157 sleep_setup(&sls, ident, priority, wmesg, timo); 158 return sleep_finish(&sls, 1); 159 } 160 161 int 162 tsleep_nsec(const volatile void *ident, int priority, const char *wmesg, 163 uint64_t nsecs) 164 { 165 uint64_t to_ticks; 166 167 if (nsecs == INFSLP) 168 return tsleep(ident, priority, wmesg, 0); 169 #ifdef DIAGNOSTIC 170 if (nsecs == 0) { 171 log(LOG_WARNING, 172 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 173 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 174 wmesg); 175 } 176 #endif 177 /* 178 * We want to sleep at least nsecs nanoseconds worth of ticks. 179 * 180 * - Clamp nsecs to prevent arithmetic overflow. 181 * 182 * - Round nsecs up to account for any nanoseconds that do not 183 * divide evenly into tick_nsec, otherwise we'll lose them to 184 * integer division in the next step. We add (tick_nsec - 1) 185 * to keep from introducing a spurious tick if there are no 186 * such nanoseconds, i.e. nsecs % tick_nsec == 0. 187 * 188 * - Divide the rounded value to a count of ticks. We divide 189 * by (tick_nsec + 1) to discard the extra tick introduced if, 190 * before rounding, nsecs % tick_nsec == 1. 191 * 192 * - Finally, add a tick to the result. We need to wait out 193 * the current tick before we can begin counting our interval, 194 * as we do not know how much time has elapsed since the 195 * current tick began. 196 */ 197 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 198 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 199 if (to_ticks > INT_MAX) 200 to_ticks = INT_MAX; 201 return tsleep(ident, priority, wmesg, (int)to_ticks); 202 } 203 204 /* 205 * Same as tsleep, but if we have a mutex provided, then once we've 206 * entered the sleep queue we drop the mutex. After sleeping we re-lock. 207 */ 208 int 209 msleep(const volatile void *ident, struct mutex *mtx, int priority, 210 const char *wmesg, int timo) 211 { 212 struct sleep_state sls; 213 int error, spl; 214 #ifdef MULTIPROCESSOR 215 int hold_count; 216 #endif 217 218 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 219 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 220 KASSERT(mtx != NULL); 221 222 #ifdef DDB 223 if (cold == 2) 224 db_stack_dump(); 225 #endif 226 if (cold || panicstr) { 227 /* 228 * After a panic, or during autoconfiguration, 229 * just give interrupts a chance, then just return; 230 * don't run any other procs or panic below, 231 * in case this is the idle process and already asleep. 232 */ 233 spl = MUTEX_OLDIPL(mtx); 234 MUTEX_OLDIPL(mtx) = safepri; 235 mtx_leave(mtx); 236 #ifdef MULTIPROCESSOR 237 if (_kernel_lock_held()) { 238 hold_count = __mp_release_all(&kernel_lock); 239 __mp_acquire_count(&kernel_lock, hold_count); 240 } 241 #endif 242 if ((priority & PNORELOCK) == 0) { 243 mtx_enter(mtx); 244 MUTEX_OLDIPL(mtx) = spl; 245 } else 246 splx(spl); 247 return (0); 248 } 249 250 sleep_setup(&sls, ident, priority, wmesg, timo); 251 252 /* XXX - We need to make sure that the mutex doesn't 253 * unblock splsched. This can be made a bit more 254 * correct when the sched_lock is a mutex. 255 */ 256 spl = MUTEX_OLDIPL(mtx); 257 MUTEX_OLDIPL(mtx) = splsched(); 258 mtx_leave(mtx); 259 /* signal may stop the process, release mutex before that */ 260 error = sleep_finish(&sls, 1); 261 262 if ((priority & PNORELOCK) == 0) { 263 mtx_enter(mtx); 264 MUTEX_OLDIPL(mtx) = spl; /* put the ipl back */ 265 } else 266 splx(spl); 267 268 return error; 269 } 270 271 int 272 msleep_nsec(const volatile void *ident, struct mutex *mtx, int priority, 273 const char *wmesg, uint64_t nsecs) 274 { 275 uint64_t to_ticks; 276 277 if (nsecs == INFSLP) 278 return msleep(ident, mtx, priority, wmesg, 0); 279 #ifdef DIAGNOSTIC 280 if (nsecs == 0) { 281 log(LOG_WARNING, 282 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 283 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 284 wmesg); 285 } 286 #endif 287 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 288 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 289 if (to_ticks > INT_MAX) 290 to_ticks = INT_MAX; 291 return msleep(ident, mtx, priority, wmesg, (int)to_ticks); 292 } 293 294 /* 295 * Same as tsleep, but if we have a rwlock provided, then once we've 296 * entered the sleep queue we drop the it. After sleeping we re-lock. 297 */ 298 int 299 rwsleep(const volatile void *ident, struct rwlock *rwl, int priority, 300 const char *wmesg, int timo) 301 { 302 struct sleep_state sls; 303 int error, status; 304 305 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 306 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 307 rw_assert_anylock(rwl); 308 status = rw_status(rwl); 309 310 sleep_setup(&sls, ident, priority, wmesg, timo); 311 312 rw_exit(rwl); 313 /* signal may stop the process, release rwlock before that */ 314 error = sleep_finish(&sls, 1); 315 316 if ((priority & PNORELOCK) == 0) 317 rw_enter(rwl, status); 318 319 return error; 320 } 321 322 int 323 rwsleep_nsec(const volatile void *ident, struct rwlock *rwl, int priority, 324 const char *wmesg, uint64_t nsecs) 325 { 326 uint64_t to_ticks; 327 328 if (nsecs == INFSLP) 329 return rwsleep(ident, rwl, priority, wmesg, 0); 330 #ifdef DIAGNOSTIC 331 if (nsecs == 0) { 332 log(LOG_WARNING, 333 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 334 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 335 wmesg); 336 } 337 #endif 338 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 339 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 340 if (to_ticks > INT_MAX) 341 to_ticks = INT_MAX; 342 return rwsleep(ident, rwl, priority, wmesg, (int)to_ticks); 343 } 344 345 void 346 sleep_setup(struct sleep_state *sls, const volatile void *ident, int prio, 347 const char *wmesg, int timo) 348 { 349 struct proc *p = curproc; 350 351 #ifdef DIAGNOSTIC 352 if (p->p_flag & P_CANTSLEEP) 353 panic("sleep: %s failed insomnia", p->p_p->ps_comm); 354 if (ident == NULL) 355 panic("tsleep: no ident"); 356 if (p->p_stat != SONPROC) 357 panic("tsleep: not SONPROC"); 358 #endif 359 360 sls->sls_catch = prio & PCATCH; 361 sls->sls_timeout = 0; 362 363 SCHED_LOCK(sls->sls_s); 364 365 TRACEPOINT(sched, sleep, NULL); 366 367 p->p_wchan = ident; 368 p->p_wmesg = wmesg; 369 p->p_slptime = 0; 370 p->p_slppri = prio & PRIMASK; 371 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); 372 373 KASSERT((p->p_flag & P_TIMEOUT) == 0); 374 if (timo) { 375 sls->sls_timeout = 1; 376 timeout_add(&p->p_sleep_to, timo); 377 } 378 } 379 380 int 381 sleep_finish(struct sleep_state *sls, int do_sleep) 382 { 383 struct proc *p = curproc; 384 int error = 0, error1 = 0; 385 386 if (sls->sls_catch != 0) { 387 /* 388 * We put ourselves on the sleep queue and start our 389 * timeout before calling sleep_signal_check(), as we could 390 * stop there, and a wakeup or a SIGCONT (or both) could 391 * occur while we were stopped. A SIGCONT would cause 392 * us to be marked as SSLEEP without resuming us, thus 393 * we must be ready for sleep when sleep_signal_check() is 394 * called. 395 * If the wakeup happens while we're stopped, p->p_wchan 396 * will be NULL upon return from sleep_signal_check(). In 397 * that case we need to unwind immediately. 398 */ 399 atomic_setbits_int(&p->p_flag, P_SINTR); 400 if ((error = sleep_signal_check()) != 0) { 401 p->p_stat = SONPROC; 402 sls->sls_catch = 0; 403 do_sleep = 0; 404 } else if (p->p_wchan == NULL) { 405 sls->sls_catch = 0; 406 do_sleep = 0; 407 } 408 } 409 410 if (do_sleep) { 411 p->p_stat = SSLEEP; 412 p->p_ru.ru_nvcsw++; 413 SCHED_ASSERT_LOCKED(); 414 mi_switch(); 415 } else { 416 unsleep(p); 417 } 418 419 #ifdef DIAGNOSTIC 420 if (p->p_stat != SONPROC) 421 panic("sleep_finish !SONPROC"); 422 #endif 423 424 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 425 SCHED_UNLOCK(sls->sls_s); 426 427 /* 428 * Even though this belongs to the signal handling part of sleep, 429 * we need to clear it before the ktrace. 430 */ 431 atomic_clearbits_int(&p->p_flag, P_SINTR); 432 433 if (sls->sls_timeout) { 434 if (p->p_flag & P_TIMEOUT) { 435 atomic_clearbits_int(&p->p_flag, P_TIMEOUT); 436 error1 = EWOULDBLOCK; 437 } else { 438 /* This must not sleep. */ 439 timeout_del_barrier(&p->p_sleep_to); 440 KASSERT((p->p_flag & P_TIMEOUT) == 0); 441 } 442 } 443 444 /* Check if thread was woken up because of a unwind or signal */ 445 if (sls->sls_catch != 0) 446 error = sleep_signal_check(); 447 448 /* Signal errors are higher priority than timeouts. */ 449 if (error == 0 && error1 != 0) 450 error = error1; 451 452 return error; 453 } 454 455 /* 456 * Check and handle signals and suspensions around a sleep cycle. 457 */ 458 int 459 sleep_signal_check(void) 460 { 461 struct proc *p = curproc; 462 struct sigctx ctx; 463 int err, sig; 464 465 if ((err = single_thread_check(p, 1)) != 0) 466 return err; 467 if ((sig = cursig(p, &ctx)) != 0) { 468 if (ctx.sig_intr) 469 return EINTR; 470 else 471 return ERESTART; 472 } 473 return 0; 474 } 475 476 int 477 wakeup_proc(struct proc *p, const volatile void *chan) 478 { 479 int s, awakened = 0; 480 481 SCHED_LOCK(s); 482 if (p->p_wchan != NULL && 483 ((chan == NULL) || (p->p_wchan == chan))) { 484 awakened = 1; 485 if (p->p_stat == SSLEEP) 486 setrunnable(p); 487 else 488 unsleep(p); 489 } 490 SCHED_UNLOCK(s); 491 492 return awakened; 493 } 494 495 496 /* 497 * Implement timeout for tsleep. 498 * If process hasn't been awakened (wchan non-zero), 499 * set timeout flag and undo the sleep. If proc 500 * is stopped, just unsleep so it will remain stopped. 501 */ 502 void 503 endtsleep(void *arg) 504 { 505 struct proc *p = arg; 506 int s; 507 508 SCHED_LOCK(s); 509 if (wakeup_proc(p, NULL)) 510 atomic_setbits_int(&p->p_flag, P_TIMEOUT); 511 SCHED_UNLOCK(s); 512 } 513 514 /* 515 * Remove a process from its wait queue 516 */ 517 void 518 unsleep(struct proc *p) 519 { 520 SCHED_ASSERT_LOCKED(); 521 522 if (p->p_wchan != NULL) { 523 TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); 524 p->p_wchan = NULL; 525 TRACEPOINT(sched, wakeup, p->p_tid + THREAD_PID_OFFSET, 526 p->p_p->ps_pid); 527 } 528 } 529 530 /* 531 * Make a number of processes sleeping on the specified identifier runnable. 532 */ 533 void 534 wakeup_n(const volatile void *ident, int n) 535 { 536 struct slpque *qp; 537 struct proc *p; 538 struct proc *pnext; 539 int s; 540 541 SCHED_LOCK(s); 542 qp = &slpque[LOOKUP(ident)]; 543 for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { 544 pnext = TAILQ_NEXT(p, p_runq); 545 /* 546 * This happens if wakeup(9) is called after enqueuing 547 * itself on the sleep queue and both `ident' collide. 548 */ 549 if (p == curproc) 550 continue; 551 #ifdef DIAGNOSTIC 552 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 553 panic("wakeup: p_stat is %d", (int)p->p_stat); 554 #endif 555 if (wakeup_proc(p, ident)) 556 --n; 557 } 558 SCHED_UNLOCK(s); 559 } 560 561 /* 562 * Make all processes sleeping on the specified identifier runnable. 563 */ 564 void 565 wakeup(const volatile void *chan) 566 { 567 wakeup_n(chan, -1); 568 } 569 570 int 571 sys_sched_yield(struct proc *p, void *v, register_t *retval) 572 { 573 struct proc *q; 574 uint8_t newprio; 575 int s; 576 577 SCHED_LOCK(s); 578 /* 579 * If one of the threads of a multi-threaded process called 580 * sched_yield(2), drop its priority to ensure its siblings 581 * can make some progress. 582 */ 583 newprio = p->p_usrpri; 584 TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) 585 newprio = max(newprio, q->p_runpri); 586 setrunqueue(p->p_cpu, p, newprio); 587 p->p_ru.ru_nvcsw++; 588 mi_switch(); 589 SCHED_UNLOCK(s); 590 591 return (0); 592 } 593 594 int 595 thrsleep_unlock(void *lock) 596 { 597 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 598 _atomic_lock_t *atomiclock = lock; 599 600 if (!lock) 601 return 0; 602 603 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 604 } 605 606 struct tslpentry { 607 TAILQ_ENTRY(tslpentry) tslp_link; 608 long tslp_ident; 609 }; 610 611 /* thrsleep queue shared between processes */ 612 static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 613 static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 614 615 int 616 thrsleep(struct proc *p, struct sys___thrsleep_args *v) 617 { 618 struct sys___thrsleep_args /* { 619 syscallarg(const volatile void *) ident; 620 syscallarg(clockid_t) clock_id; 621 syscallarg(const struct timespec *) tp; 622 syscallarg(void *) lock; 623 syscallarg(const int *) abort; 624 } */ *uap = v; 625 long ident = (long)SCARG(uap, ident); 626 struct tslpentry entry; 627 struct tslpqueue *queue; 628 struct rwlock *qlock; 629 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 630 void *lock = SCARG(uap, lock); 631 uint64_t nsecs = INFSLP; 632 int abort = 0, error; 633 clockid_t clock_id = SCARG(uap, clock_id); 634 635 if (ident == 0) 636 return (EINVAL); 637 if (tsp != NULL) { 638 struct timespec now; 639 640 if ((error = clock_gettime(p, clock_id, &now))) 641 return (error); 642 #ifdef KTRACE 643 if (KTRPOINT(p, KTR_STRUCT)) 644 ktrabstimespec(p, tsp); 645 #endif 646 647 if (timespeccmp(tsp, &now, <=)) { 648 /* already passed: still do the unlock */ 649 if ((error = thrsleep_unlock(lock))) 650 return (error); 651 return (EWOULDBLOCK); 652 } 653 654 timespecsub(tsp, &now, tsp); 655 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 656 } 657 658 if (ident == -1) { 659 queue = &thrsleep_queue; 660 qlock = &thrsleep_lock; 661 } else { 662 queue = &p->p_p->ps_tslpqueue; 663 qlock = &p->p_p->ps_lock; 664 } 665 666 /* Interlock with wakeup. */ 667 entry.tslp_ident = ident; 668 rw_enter_write(qlock); 669 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 670 rw_exit_write(qlock); 671 672 error = thrsleep_unlock(lock); 673 674 if (error == 0 && SCARG(uap, abort) != NULL) 675 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 676 677 rw_enter_write(qlock); 678 if (error != 0) 679 goto out; 680 if (abort != 0) { 681 error = EINTR; 682 goto out; 683 } 684 if (entry.tslp_ident != 0) { 685 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 686 nsecs); 687 } 688 689 out: 690 if (entry.tslp_ident != 0) 691 TAILQ_REMOVE(queue, &entry, tslp_link); 692 rw_exit_write(qlock); 693 694 if (error == ERESTART) 695 error = ECANCELED; 696 697 return (error); 698 699 } 700 701 int 702 sys___thrsleep(struct proc *p, void *v, register_t *retval) 703 { 704 struct sys___thrsleep_args /* { 705 syscallarg(const volatile void *) ident; 706 syscallarg(clockid_t) clock_id; 707 syscallarg(struct timespec *) tp; 708 syscallarg(void *) lock; 709 syscallarg(const int *) abort; 710 } */ *uap = v; 711 struct timespec ts; 712 int error; 713 714 if (SCARG(uap, tp) != NULL) { 715 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 716 *retval = error; 717 return 0; 718 } 719 if (!timespecisvalid(&ts)) { 720 *retval = EINVAL; 721 return 0; 722 } 723 SCARG(uap, tp) = &ts; 724 } 725 726 *retval = thrsleep(p, uap); 727 return 0; 728 } 729 730 int 731 sys___thrwakeup(struct proc *p, void *v, register_t *retval) 732 { 733 struct sys___thrwakeup_args /* { 734 syscallarg(const volatile void *) ident; 735 syscallarg(int) n; 736 } */ *uap = v; 737 struct tslpentry *entry, *tmp; 738 struct tslpqueue *queue; 739 struct rwlock *qlock; 740 long ident = (long)SCARG(uap, ident); 741 int n = SCARG(uap, n); 742 int found = 0; 743 744 if (ident == 0) 745 *retval = EINVAL; 746 else { 747 if (ident == -1) { 748 queue = &thrsleep_queue; 749 qlock = &thrsleep_lock; 750 /* 751 * Wake up all waiters with ident -1. This is needed 752 * because ident -1 can be shared by multiple userspace 753 * lock state machines concurrently. The implementation 754 * has no way to direct the wakeup to a particular 755 * state machine. 756 */ 757 n = 0; 758 } else { 759 queue = &p->p_p->ps_tslpqueue; 760 qlock = &p->p_p->ps_lock; 761 } 762 763 rw_enter_write(qlock); 764 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 765 if (entry->tslp_ident == ident) { 766 TAILQ_REMOVE(queue, entry, tslp_link); 767 entry->tslp_ident = 0; 768 wakeup_one(entry); 769 if (++found == n) 770 break; 771 } 772 } 773 rw_exit_write(qlock); 774 775 if (ident == -1) 776 *retval = 0; 777 else 778 *retval = found ? 0 : ESRCH; 779 } 780 781 return (0); 782 } 783 784 void 785 refcnt_init(struct refcnt *r) 786 { 787 atomic_store_int(&r->r_refs, 1); 788 } 789 790 void 791 refcnt_take(struct refcnt *r) 792 { 793 u_int refs; 794 795 refs = atomic_inc_int_nv(&r->r_refs); 796 KASSERT(refs != 0); 797 (void)refs; 798 } 799 800 int 801 refcnt_rele(struct refcnt *r) 802 { 803 u_int refs; 804 805 membar_exit_before_atomic(); 806 refs = atomic_dec_int_nv(&r->r_refs); 807 KASSERT(refs != ~0); 808 if (refs == 0) { 809 membar_enter_after_atomic(); 810 return (1); 811 } 812 return (0); 813 } 814 815 void 816 refcnt_rele_wake(struct refcnt *r) 817 { 818 if (refcnt_rele(r)) 819 wakeup_one(r); 820 } 821 822 void 823 refcnt_finalize(struct refcnt *r, const char *wmesg) 824 { 825 struct sleep_state sls; 826 u_int refs; 827 828 membar_exit_before_atomic(); 829 refs = atomic_dec_int_nv(&r->r_refs); 830 KASSERT(refs != ~0); 831 while (refs) { 832 sleep_setup(&sls, r, PWAIT, wmesg, 0); 833 refs = atomic_load_int(&r->r_refs); 834 sleep_finish(&sls, refs); 835 } 836 /* Order subsequent loads and stores after refs == 0 load. */ 837 membar_sync(); 838 } 839 840 int 841 refcnt_shared(struct refcnt *r) 842 { 843 u_int refs; 844 845 refs = atomic_load_int(&r->r_refs); 846 return (refs > 1); 847 } 848 849 unsigned int 850 refcnt_read(struct refcnt *r) 851 { 852 u_int refs; 853 854 refs = atomic_load_int(&r->r_refs); 855 return (refs); 856 } 857 858 void 859 cond_init(struct cond *c) 860 { 861 atomic_store_int(&c->c_wait, 1); 862 } 863 864 void 865 cond_signal(struct cond *c) 866 { 867 atomic_store_int(&c->c_wait, 0); 868 869 wakeup_one(c); 870 } 871 872 void 873 cond_wait(struct cond *c, const char *wmesg) 874 { 875 struct sleep_state sls; 876 unsigned int wait; 877 878 wait = atomic_load_int(&c->c_wait); 879 while (wait) { 880 sleep_setup(&sls, c, PWAIT, wmesg, 0); 881 wait = atomic_load_int(&c->c_wait); 882 sleep_finish(&sls, wait); 883 } 884 } 885