1 /* $OpenBSD: kern_synch.c,v 1.199 2023/09/08 09:06:31 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/sched.h> 46 #include <sys/timeout.h> 47 #include <sys/mount.h> 48 #include <sys/syscallargs.h> 49 #include <sys/refcnt.h> 50 #include <sys/atomic.h> 51 #include <sys/tracepoint.h> 52 53 #include <ddb/db_output.h> 54 55 #include <machine/spinlock.h> 56 57 #ifdef DIAGNOSTIC 58 #include <sys/syslog.h> 59 #endif 60 61 #ifdef KTRACE 62 #include <sys/ktrace.h> 63 #endif 64 65 int sleep_signal_check(void); 66 int thrsleep(struct proc *, struct sys___thrsleep_args *); 67 int thrsleep_unlock(void *); 68 69 /* 70 * We're only looking at 7 bits of the address; everything is 71 * aligned to 4, lots of things are aligned to greater powers 72 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 73 */ 74 #define TABLESIZE 128 75 #define LOOKUP(x) (((long)(x) >> 8) & (TABLESIZE - 1)) 76 TAILQ_HEAD(slpque,proc) slpque[TABLESIZE]; 77 78 void 79 sleep_queue_init(void) 80 { 81 int i; 82 83 for (i = 0; i < TABLESIZE; i++) 84 TAILQ_INIT(&slpque[i]); 85 } 86 87 /* 88 * Global sleep channel for threads that do not want to 89 * receive wakeup(9) broadcasts. 90 */ 91 int nowake; 92 93 /* 94 * During autoconfiguration or after a panic, a sleep will simply 95 * lower the priority briefly to allow interrupts, then return. 96 * The priority to be used (safepri) is machine-dependent, thus this 97 * value is initialized and maintained in the machine-dependent layers. 98 * This priority will typically be 0, or the lowest priority 99 * that is safe for use on the interrupt stack; it can be made 100 * higher to block network software interrupts after panics. 101 */ 102 extern int safepri; 103 104 /* 105 * General sleep call. Suspends the current process until a wakeup is 106 * performed on the specified identifier. The process will then be made 107 * runnable with the specified priority. Sleeps at most timo/hz seconds 108 * (0 means no timeout). If pri includes PCATCH flag, signals are checked 109 * before and after sleeping, else signals are not checked. Returns 0 if 110 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 111 * signal needs to be delivered, ERESTART is returned if the current system 112 * call should be restarted if possible, and EINTR is returned if the system 113 * call should be interrupted by the signal (return EINTR). 114 */ 115 int 116 tsleep(const volatile void *ident, int priority, const char *wmesg, int timo) 117 { 118 #ifdef MULTIPROCESSOR 119 int hold_count; 120 #endif 121 122 KASSERT((priority & ~(PRIMASK | PCATCH)) == 0); 123 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 124 125 #ifdef MULTIPROCESSOR 126 KASSERT(ident == &nowake || timo || _kernel_lock_held()); 127 #endif 128 129 #ifdef DDB 130 if (cold == 2) 131 db_stack_dump(); 132 #endif 133 if (cold || panicstr) { 134 int s; 135 /* 136 * After a panic, or during autoconfiguration, 137 * just give interrupts a chance, then just return; 138 * don't run any other procs or panic below, 139 * in case this is the idle process and already asleep. 140 */ 141 s = splhigh(); 142 splx(safepri); 143 #ifdef MULTIPROCESSOR 144 if (_kernel_lock_held()) { 145 hold_count = __mp_release_all(&kernel_lock); 146 __mp_acquire_count(&kernel_lock, hold_count); 147 } 148 #endif 149 splx(s); 150 return (0); 151 } 152 153 sleep_setup(ident, priority, wmesg); 154 return sleep_finish(timo, 1); 155 } 156 157 int 158 tsleep_nsec(const volatile void *ident, int priority, const char *wmesg, 159 uint64_t nsecs) 160 { 161 uint64_t to_ticks; 162 163 if (nsecs == INFSLP) 164 return tsleep(ident, priority, wmesg, 0); 165 #ifdef DIAGNOSTIC 166 if (nsecs == 0) { 167 log(LOG_WARNING, 168 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 169 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 170 wmesg); 171 } 172 #endif 173 /* 174 * We want to sleep at least nsecs nanoseconds worth of ticks. 175 * 176 * - Clamp nsecs to prevent arithmetic overflow. 177 * 178 * - Round nsecs up to account for any nanoseconds that do not 179 * divide evenly into tick_nsec, otherwise we'll lose them to 180 * integer division in the next step. We add (tick_nsec - 1) 181 * to keep from introducing a spurious tick if there are no 182 * such nanoseconds, i.e. nsecs % tick_nsec == 0. 183 * 184 * - Divide the rounded value to a count of ticks. We divide 185 * by (tick_nsec + 1) to discard the extra tick introduced if, 186 * before rounding, nsecs % tick_nsec == 1. 187 * 188 * - Finally, add a tick to the result. We need to wait out 189 * the current tick before we can begin counting our interval, 190 * as we do not know how much time has elapsed since the 191 * current tick began. 192 */ 193 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 194 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 195 if (to_ticks > INT_MAX) 196 to_ticks = INT_MAX; 197 return tsleep(ident, priority, wmesg, (int)to_ticks); 198 } 199 200 /* 201 * Same as tsleep, but if we have a mutex provided, then once we've 202 * entered the sleep queue we drop the mutex. After sleeping we re-lock. 203 */ 204 int 205 msleep(const volatile void *ident, struct mutex *mtx, int priority, 206 const char *wmesg, int timo) 207 { 208 int error, spl; 209 #ifdef MULTIPROCESSOR 210 int hold_count; 211 #endif 212 213 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 214 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 215 KASSERT(mtx != NULL); 216 217 #ifdef DDB 218 if (cold == 2) 219 db_stack_dump(); 220 #endif 221 if (cold || panicstr) { 222 /* 223 * After a panic, or during autoconfiguration, 224 * just give interrupts a chance, then just return; 225 * don't run any other procs or panic below, 226 * in case this is the idle process and already asleep. 227 */ 228 spl = MUTEX_OLDIPL(mtx); 229 MUTEX_OLDIPL(mtx) = safepri; 230 mtx_leave(mtx); 231 #ifdef MULTIPROCESSOR 232 if (_kernel_lock_held()) { 233 hold_count = __mp_release_all(&kernel_lock); 234 __mp_acquire_count(&kernel_lock, hold_count); 235 } 236 #endif 237 if ((priority & PNORELOCK) == 0) { 238 mtx_enter(mtx); 239 MUTEX_OLDIPL(mtx) = spl; 240 } else 241 splx(spl); 242 return (0); 243 } 244 245 sleep_setup(ident, priority, wmesg); 246 247 mtx_leave(mtx); 248 /* signal may stop the process, release mutex before that */ 249 error = sleep_finish(timo, 1); 250 251 if ((priority & PNORELOCK) == 0) 252 mtx_enter(mtx); 253 254 return error; 255 } 256 257 int 258 msleep_nsec(const volatile void *ident, struct mutex *mtx, int priority, 259 const char *wmesg, uint64_t nsecs) 260 { 261 uint64_t to_ticks; 262 263 if (nsecs == INFSLP) 264 return msleep(ident, mtx, priority, wmesg, 0); 265 #ifdef DIAGNOSTIC 266 if (nsecs == 0) { 267 log(LOG_WARNING, 268 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 269 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 270 wmesg); 271 } 272 #endif 273 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 274 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 275 if (to_ticks > INT_MAX) 276 to_ticks = INT_MAX; 277 return msleep(ident, mtx, priority, wmesg, (int)to_ticks); 278 } 279 280 /* 281 * Same as tsleep, but if we have a rwlock provided, then once we've 282 * entered the sleep queue we drop the it. After sleeping we re-lock. 283 */ 284 int 285 rwsleep(const volatile void *ident, struct rwlock *rwl, int priority, 286 const char *wmesg, int timo) 287 { 288 int error, status; 289 290 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 291 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 292 KASSERT(ident != rwl); 293 rw_assert_anylock(rwl); 294 status = rw_status(rwl); 295 296 sleep_setup(ident, priority, wmesg); 297 298 rw_exit(rwl); 299 /* signal may stop the process, release rwlock before that */ 300 error = sleep_finish(timo, 1); 301 302 if ((priority & PNORELOCK) == 0) 303 rw_enter(rwl, status); 304 305 return error; 306 } 307 308 int 309 rwsleep_nsec(const volatile void *ident, struct rwlock *rwl, int priority, 310 const char *wmesg, uint64_t nsecs) 311 { 312 uint64_t to_ticks; 313 314 if (nsecs == INFSLP) 315 return rwsleep(ident, rwl, priority, wmesg, 0); 316 #ifdef DIAGNOSTIC 317 if (nsecs == 0) { 318 log(LOG_WARNING, 319 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 320 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 321 wmesg); 322 } 323 #endif 324 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 325 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 326 if (to_ticks > INT_MAX) 327 to_ticks = INT_MAX; 328 return rwsleep(ident, rwl, priority, wmesg, (int)to_ticks); 329 } 330 331 void 332 sleep_setup(const volatile void *ident, int prio, const char *wmesg) 333 { 334 struct proc *p = curproc; 335 int s; 336 337 #ifdef DIAGNOSTIC 338 if (p->p_flag & P_CANTSLEEP) 339 panic("sleep: %s failed insomnia", p->p_p->ps_comm); 340 if (ident == NULL) 341 panic("tsleep: no ident"); 342 if (p->p_stat != SONPROC) 343 panic("tsleep: not SONPROC"); 344 #endif 345 346 SCHED_LOCK(s); 347 348 TRACEPOINT(sched, sleep, NULL); 349 350 p->p_wchan = ident; 351 p->p_wmesg = wmesg; 352 p->p_slptime = 0; 353 p->p_slppri = prio & PRIMASK; 354 atomic_setbits_int(&p->p_flag, P_WSLEEP); 355 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); 356 if (prio & PCATCH) 357 atomic_setbits_int(&p->p_flag, P_SINTR); 358 p->p_stat = SSLEEP; 359 360 SCHED_UNLOCK(s); 361 } 362 363 int 364 sleep_finish(int timo, int do_sleep) 365 { 366 struct proc *p = curproc; 367 int s, catch, error = 0, error1 = 0; 368 369 catch = p->p_flag & P_SINTR; 370 371 if (timo != 0) { 372 KASSERT((p->p_flag & P_TIMEOUT) == 0); 373 timeout_add(&p->p_sleep_to, timo); 374 } 375 376 if (catch != 0) { 377 /* 378 * We put ourselves on the sleep queue and start our 379 * timeout before calling sleep_signal_check(), as we could 380 * stop there, and a wakeup or a SIGCONT (or both) could 381 * occur while we were stopped. A SIGCONT would cause 382 * us to be marked as SSLEEP without resuming us, thus 383 * we must be ready for sleep when sleep_signal_check() is 384 * called. 385 */ 386 if ((error = sleep_signal_check()) != 0) { 387 catch = 0; 388 do_sleep = 0; 389 } 390 } 391 392 SCHED_LOCK(s); 393 /* 394 * If the wakeup happens while going to sleep, p->p_wchan 395 * will be NULL. In that case unwind immediately but still 396 * check for possible signals and timeouts. 397 */ 398 if (p->p_wchan == NULL) 399 do_sleep = 0; 400 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 401 402 if (do_sleep) { 403 KASSERT(p->p_stat == SSLEEP || p->p_stat == SSTOP); 404 p->p_ru.ru_nvcsw++; 405 mi_switch(); 406 } else { 407 KASSERT(p->p_stat == SONPROC || p->p_stat == SSLEEP || 408 p->p_stat == SSTOP); 409 unsleep(p); 410 p->p_stat = SONPROC; 411 } 412 413 #ifdef DIAGNOSTIC 414 if (p->p_stat != SONPROC) 415 panic("sleep_finish !SONPROC"); 416 #endif 417 418 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 419 SCHED_UNLOCK(s); 420 421 /* 422 * Even though this belongs to the signal handling part of sleep, 423 * we need to clear it before the ktrace. 424 */ 425 atomic_clearbits_int(&p->p_flag, P_SINTR); 426 427 if (timo != 0) { 428 if (p->p_flag & P_TIMEOUT) { 429 error1 = EWOULDBLOCK; 430 } else { 431 /* This can sleep. It must not use timeouts. */ 432 timeout_del_barrier(&p->p_sleep_to); 433 } 434 atomic_clearbits_int(&p->p_flag, P_TIMEOUT); 435 } 436 437 /* Check if thread was woken up because of a unwind or signal */ 438 if (catch != 0) 439 error = sleep_signal_check(); 440 441 /* Signal errors are higher priority than timeouts. */ 442 if (error == 0 && error1 != 0) 443 error = error1; 444 445 return error; 446 } 447 448 /* 449 * Check and handle signals and suspensions around a sleep cycle. 450 */ 451 int 452 sleep_signal_check(void) 453 { 454 struct proc *p = curproc; 455 struct sigctx ctx; 456 int err, sig; 457 458 if ((err = single_thread_check(p, 1)) != 0) 459 return err; 460 if ((sig = cursig(p, &ctx)) != 0) { 461 if (ctx.sig_intr) 462 return EINTR; 463 else 464 return ERESTART; 465 } 466 return 0; 467 } 468 469 int 470 wakeup_proc(struct proc *p, const volatile void *chan, int flags) 471 { 472 int awakened = 0; 473 474 SCHED_ASSERT_LOCKED(); 475 476 if (p->p_wchan != NULL && 477 ((chan == NULL) || (p->p_wchan == chan))) { 478 awakened = 1; 479 if (flags) 480 atomic_setbits_int(&p->p_flag, flags); 481 if (p->p_stat == SSLEEP) 482 setrunnable(p); 483 else if (p->p_stat == SSTOP) 484 unsleep(p); 485 #ifdef DIAGNOSTIC 486 else 487 panic("wakeup: p_stat is %d", (int)p->p_stat); 488 #endif 489 } 490 491 return awakened; 492 } 493 494 495 /* 496 * Implement timeout for tsleep. 497 * If process hasn't been awakened (wchan non-zero), 498 * set timeout flag and undo the sleep. If proc 499 * is stopped, just unsleep so it will remain stopped. 500 */ 501 void 502 endtsleep(void *arg) 503 { 504 struct proc *p = arg; 505 int s; 506 507 SCHED_LOCK(s); 508 wakeup_proc(p, NULL, P_TIMEOUT); 509 SCHED_UNLOCK(s); 510 } 511 512 /* 513 * Remove a process from its wait queue 514 */ 515 void 516 unsleep(struct proc *p) 517 { 518 SCHED_ASSERT_LOCKED(); 519 520 if (p->p_wchan != NULL) { 521 TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); 522 p->p_wchan = NULL; 523 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 524 p->p_p->ps_pid); 525 } 526 } 527 528 /* 529 * Make a number of processes sleeping on the specified identifier runnable. 530 */ 531 void 532 wakeup_n(const volatile void *ident, int n) 533 { 534 struct slpque *qp; 535 struct proc *p; 536 struct proc *pnext; 537 int s; 538 539 SCHED_LOCK(s); 540 qp = &slpque[LOOKUP(ident)]; 541 for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { 542 pnext = TAILQ_NEXT(p, p_runq); 543 #ifdef DIAGNOSTIC 544 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 545 panic("wakeup: p_stat is %d", (int)p->p_stat); 546 #endif 547 if (wakeup_proc(p, ident, 0)) 548 --n; 549 } 550 SCHED_UNLOCK(s); 551 } 552 553 /* 554 * Make all processes sleeping on the specified identifier runnable. 555 */ 556 void 557 wakeup(const volatile void *chan) 558 { 559 wakeup_n(chan, -1); 560 } 561 562 int 563 sys_sched_yield(struct proc *p, void *v, register_t *retval) 564 { 565 struct proc *q; 566 uint8_t newprio; 567 int s; 568 569 /* 570 * If one of the threads of a multi-threaded process called 571 * sched_yield(2), drop its priority to ensure its siblings 572 * can make some progress. 573 */ 574 mtx_enter(&p->p_p->ps_mtx); 575 newprio = p->p_usrpri; 576 TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) 577 newprio = max(newprio, q->p_runpri); 578 mtx_leave(&p->p_p->ps_mtx); 579 580 SCHED_LOCK(s); 581 setrunqueue(p->p_cpu, p, newprio); 582 p->p_ru.ru_nvcsw++; 583 mi_switch(); 584 SCHED_UNLOCK(s); 585 586 return (0); 587 } 588 589 int 590 thrsleep_unlock(void *lock) 591 { 592 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 593 _atomic_lock_t *atomiclock = lock; 594 595 if (!lock) 596 return 0; 597 598 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 599 } 600 601 struct tslpentry { 602 TAILQ_ENTRY(tslpentry) tslp_link; 603 long tslp_ident; 604 }; 605 606 /* thrsleep queue shared between processes */ 607 static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 608 static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 609 610 int 611 thrsleep(struct proc *p, struct sys___thrsleep_args *v) 612 { 613 struct sys___thrsleep_args /* { 614 syscallarg(const volatile void *) ident; 615 syscallarg(clockid_t) clock_id; 616 syscallarg(const struct timespec *) tp; 617 syscallarg(void *) lock; 618 syscallarg(const int *) abort; 619 } */ *uap = v; 620 long ident = (long)SCARG(uap, ident); 621 struct tslpentry entry; 622 struct tslpqueue *queue; 623 struct rwlock *qlock; 624 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 625 void *lock = SCARG(uap, lock); 626 uint64_t nsecs = INFSLP; 627 int abort = 0, error; 628 clockid_t clock_id = SCARG(uap, clock_id); 629 630 if (ident == 0) 631 return (EINVAL); 632 if (tsp != NULL) { 633 struct timespec now; 634 635 if ((error = clock_gettime(p, clock_id, &now))) 636 return (error); 637 #ifdef KTRACE 638 if (KTRPOINT(p, KTR_STRUCT)) 639 ktrabstimespec(p, tsp); 640 #endif 641 642 if (timespeccmp(tsp, &now, <=)) { 643 /* already passed: still do the unlock */ 644 if ((error = thrsleep_unlock(lock))) 645 return (error); 646 return (EWOULDBLOCK); 647 } 648 649 timespecsub(tsp, &now, tsp); 650 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 651 } 652 653 if (ident == -1) { 654 queue = &thrsleep_queue; 655 qlock = &thrsleep_lock; 656 } else { 657 queue = &p->p_p->ps_tslpqueue; 658 qlock = &p->p_p->ps_lock; 659 } 660 661 /* Interlock with wakeup. */ 662 entry.tslp_ident = ident; 663 rw_enter_write(qlock); 664 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 665 rw_exit_write(qlock); 666 667 error = thrsleep_unlock(lock); 668 669 if (error == 0 && SCARG(uap, abort) != NULL) 670 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 671 672 rw_enter_write(qlock); 673 if (error != 0) 674 goto out; 675 if (abort != 0) { 676 error = EINTR; 677 goto out; 678 } 679 if (entry.tslp_ident != 0) { 680 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 681 nsecs); 682 } 683 684 out: 685 if (entry.tslp_ident != 0) 686 TAILQ_REMOVE(queue, &entry, tslp_link); 687 rw_exit_write(qlock); 688 689 if (error == ERESTART) 690 error = ECANCELED; 691 692 return (error); 693 694 } 695 696 int 697 sys___thrsleep(struct proc *p, void *v, register_t *retval) 698 { 699 struct sys___thrsleep_args /* { 700 syscallarg(const volatile void *) ident; 701 syscallarg(clockid_t) clock_id; 702 syscallarg(struct timespec *) tp; 703 syscallarg(void *) lock; 704 syscallarg(const int *) abort; 705 } */ *uap = v; 706 struct timespec ts; 707 int error; 708 709 if (SCARG(uap, tp) != NULL) { 710 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 711 *retval = error; 712 return 0; 713 } 714 if (!timespecisvalid(&ts)) { 715 *retval = EINVAL; 716 return 0; 717 } 718 SCARG(uap, tp) = &ts; 719 } 720 721 *retval = thrsleep(p, uap); 722 return 0; 723 } 724 725 int 726 sys___thrwakeup(struct proc *p, void *v, register_t *retval) 727 { 728 struct sys___thrwakeup_args /* { 729 syscallarg(const volatile void *) ident; 730 syscallarg(int) n; 731 } */ *uap = v; 732 struct tslpentry *entry, *tmp; 733 struct tslpqueue *queue; 734 struct rwlock *qlock; 735 long ident = (long)SCARG(uap, ident); 736 int n = SCARG(uap, n); 737 int found = 0; 738 739 if (ident == 0) 740 *retval = EINVAL; 741 else { 742 if (ident == -1) { 743 queue = &thrsleep_queue; 744 qlock = &thrsleep_lock; 745 /* 746 * Wake up all waiters with ident -1. This is needed 747 * because ident -1 can be shared by multiple userspace 748 * lock state machines concurrently. The implementation 749 * has no way to direct the wakeup to a particular 750 * state machine. 751 */ 752 n = 0; 753 } else { 754 queue = &p->p_p->ps_tslpqueue; 755 qlock = &p->p_p->ps_lock; 756 } 757 758 rw_enter_write(qlock); 759 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 760 if (entry->tslp_ident == ident) { 761 TAILQ_REMOVE(queue, entry, tslp_link); 762 entry->tslp_ident = 0; 763 wakeup_one(entry); 764 if (++found == n) 765 break; 766 } 767 } 768 rw_exit_write(qlock); 769 770 if (ident == -1) 771 *retval = 0; 772 else 773 *retval = found ? 0 : ESRCH; 774 } 775 776 return (0); 777 } 778 779 void 780 refcnt_init(struct refcnt *r) 781 { 782 refcnt_init_trace(r, 0); 783 } 784 785 void 786 refcnt_init_trace(struct refcnt *r, int idx) 787 { 788 r->r_traceidx = idx; 789 atomic_store_int(&r->r_refs, 1); 790 TRACEINDEX(refcnt, r->r_traceidx, r, 0, +1); 791 } 792 793 void 794 refcnt_take(struct refcnt *r) 795 { 796 u_int refs; 797 798 refs = atomic_inc_int_nv(&r->r_refs); 799 KASSERT(refs != 0); 800 TRACEINDEX(refcnt, r->r_traceidx, r, refs - 1, +1); 801 (void)refs; 802 } 803 804 int 805 refcnt_rele(struct refcnt *r) 806 { 807 u_int refs; 808 809 membar_exit_before_atomic(); 810 refs = atomic_dec_int_nv(&r->r_refs); 811 KASSERT(refs != ~0); 812 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 813 if (refs == 0) { 814 membar_enter_after_atomic(); 815 return (1); 816 } 817 return (0); 818 } 819 820 void 821 refcnt_rele_wake(struct refcnt *r) 822 { 823 if (refcnt_rele(r)) 824 wakeup_one(r); 825 } 826 827 void 828 refcnt_finalize(struct refcnt *r, const char *wmesg) 829 { 830 u_int refs; 831 832 membar_exit_before_atomic(); 833 refs = atomic_dec_int_nv(&r->r_refs); 834 KASSERT(refs != ~0); 835 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 836 while (refs) { 837 sleep_setup(r, PWAIT, wmesg); 838 refs = atomic_load_int(&r->r_refs); 839 sleep_finish(0, refs); 840 } 841 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 842 /* Order subsequent loads and stores after refs == 0 load. */ 843 membar_sync(); 844 } 845 846 int 847 refcnt_shared(struct refcnt *r) 848 { 849 u_int refs; 850 851 refs = atomic_load_int(&r->r_refs); 852 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 853 return (refs > 1); 854 } 855 856 unsigned int 857 refcnt_read(struct refcnt *r) 858 { 859 u_int refs; 860 861 refs = atomic_load_int(&r->r_refs); 862 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 863 return (refs); 864 } 865 866 void 867 cond_init(struct cond *c) 868 { 869 atomic_store_int(&c->c_wait, 1); 870 } 871 872 void 873 cond_signal(struct cond *c) 874 { 875 atomic_store_int(&c->c_wait, 0); 876 877 wakeup_one(c); 878 } 879 880 void 881 cond_wait(struct cond *c, const char *wmesg) 882 { 883 unsigned int wait; 884 885 wait = atomic_load_int(&c->c_wait); 886 while (wait) { 887 sleep_setup(c, PWAIT, wmesg); 888 wait = atomic_load_int(&c->c_wait); 889 sleep_finish(0, wait); 890 } 891 } 892