1 /* $OpenBSD: kern_synch.c,v 1.197 2023/08/14 08:33:24 mpi 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 SCHED_LOCK(s); 377 if (catch != 0) { 378 /* 379 * We put ourselves on the sleep queue and start our 380 * timeout before calling sleep_signal_check(), as we could 381 * stop there, and a wakeup or a SIGCONT (or both) could 382 * occur while we were stopped. A SIGCONT would cause 383 * us to be marked as SSLEEP without resuming us, thus 384 * we must be ready for sleep when sleep_signal_check() is 385 * called. 386 */ 387 if ((error = sleep_signal_check()) != 0) { 388 catch = 0; 389 do_sleep = 0; 390 } 391 } 392 393 /* 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 SCHED_LOCK(s); 570 /* 571 * If one of the threads of a multi-threaded process called 572 * sched_yield(2), drop its priority to ensure its siblings 573 * can make some progress. 574 */ 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 setrunqueue(p->p_cpu, p, newprio); 579 p->p_ru.ru_nvcsw++; 580 mi_switch(); 581 SCHED_UNLOCK(s); 582 583 return (0); 584 } 585 586 int 587 thrsleep_unlock(void *lock) 588 { 589 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 590 _atomic_lock_t *atomiclock = lock; 591 592 if (!lock) 593 return 0; 594 595 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 596 } 597 598 struct tslpentry { 599 TAILQ_ENTRY(tslpentry) tslp_link; 600 long tslp_ident; 601 }; 602 603 /* thrsleep queue shared between processes */ 604 static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 605 static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 606 607 int 608 thrsleep(struct proc *p, struct sys___thrsleep_args *v) 609 { 610 struct sys___thrsleep_args /* { 611 syscallarg(const volatile void *) ident; 612 syscallarg(clockid_t) clock_id; 613 syscallarg(const struct timespec *) tp; 614 syscallarg(void *) lock; 615 syscallarg(const int *) abort; 616 } */ *uap = v; 617 long ident = (long)SCARG(uap, ident); 618 struct tslpentry entry; 619 struct tslpqueue *queue; 620 struct rwlock *qlock; 621 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 622 void *lock = SCARG(uap, lock); 623 uint64_t nsecs = INFSLP; 624 int abort = 0, error; 625 clockid_t clock_id = SCARG(uap, clock_id); 626 627 if (ident == 0) 628 return (EINVAL); 629 if (tsp != NULL) { 630 struct timespec now; 631 632 if ((error = clock_gettime(p, clock_id, &now))) 633 return (error); 634 #ifdef KTRACE 635 if (KTRPOINT(p, KTR_STRUCT)) 636 ktrabstimespec(p, tsp); 637 #endif 638 639 if (timespeccmp(tsp, &now, <=)) { 640 /* already passed: still do the unlock */ 641 if ((error = thrsleep_unlock(lock))) 642 return (error); 643 return (EWOULDBLOCK); 644 } 645 646 timespecsub(tsp, &now, tsp); 647 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 648 } 649 650 if (ident == -1) { 651 queue = &thrsleep_queue; 652 qlock = &thrsleep_lock; 653 } else { 654 queue = &p->p_p->ps_tslpqueue; 655 qlock = &p->p_p->ps_lock; 656 } 657 658 /* Interlock with wakeup. */ 659 entry.tslp_ident = ident; 660 rw_enter_write(qlock); 661 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 662 rw_exit_write(qlock); 663 664 error = thrsleep_unlock(lock); 665 666 if (error == 0 && SCARG(uap, abort) != NULL) 667 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 668 669 rw_enter_write(qlock); 670 if (error != 0) 671 goto out; 672 if (abort != 0) { 673 error = EINTR; 674 goto out; 675 } 676 if (entry.tslp_ident != 0) { 677 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 678 nsecs); 679 } 680 681 out: 682 if (entry.tslp_ident != 0) 683 TAILQ_REMOVE(queue, &entry, tslp_link); 684 rw_exit_write(qlock); 685 686 if (error == ERESTART) 687 error = ECANCELED; 688 689 return (error); 690 691 } 692 693 int 694 sys___thrsleep(struct proc *p, void *v, register_t *retval) 695 { 696 struct sys___thrsleep_args /* { 697 syscallarg(const volatile void *) ident; 698 syscallarg(clockid_t) clock_id; 699 syscallarg(struct timespec *) tp; 700 syscallarg(void *) lock; 701 syscallarg(const int *) abort; 702 } */ *uap = v; 703 struct timespec ts; 704 int error; 705 706 if (SCARG(uap, tp) != NULL) { 707 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 708 *retval = error; 709 return 0; 710 } 711 if (!timespecisvalid(&ts)) { 712 *retval = EINVAL; 713 return 0; 714 } 715 SCARG(uap, tp) = &ts; 716 } 717 718 *retval = thrsleep(p, uap); 719 return 0; 720 } 721 722 int 723 sys___thrwakeup(struct proc *p, void *v, register_t *retval) 724 { 725 struct sys___thrwakeup_args /* { 726 syscallarg(const volatile void *) ident; 727 syscallarg(int) n; 728 } */ *uap = v; 729 struct tslpentry *entry, *tmp; 730 struct tslpqueue *queue; 731 struct rwlock *qlock; 732 long ident = (long)SCARG(uap, ident); 733 int n = SCARG(uap, n); 734 int found = 0; 735 736 if (ident == 0) 737 *retval = EINVAL; 738 else { 739 if (ident == -1) { 740 queue = &thrsleep_queue; 741 qlock = &thrsleep_lock; 742 /* 743 * Wake up all waiters with ident -1. This is needed 744 * because ident -1 can be shared by multiple userspace 745 * lock state machines concurrently. The implementation 746 * has no way to direct the wakeup to a particular 747 * state machine. 748 */ 749 n = 0; 750 } else { 751 queue = &p->p_p->ps_tslpqueue; 752 qlock = &p->p_p->ps_lock; 753 } 754 755 rw_enter_write(qlock); 756 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 757 if (entry->tslp_ident == ident) { 758 TAILQ_REMOVE(queue, entry, tslp_link); 759 entry->tslp_ident = 0; 760 wakeup_one(entry); 761 if (++found == n) 762 break; 763 } 764 } 765 rw_exit_write(qlock); 766 767 if (ident == -1) 768 *retval = 0; 769 else 770 *retval = found ? 0 : ESRCH; 771 } 772 773 return (0); 774 } 775 776 void 777 refcnt_init(struct refcnt *r) 778 { 779 refcnt_init_trace(r, 0); 780 } 781 782 void 783 refcnt_init_trace(struct refcnt *r, int idx) 784 { 785 r->r_traceidx = idx; 786 atomic_store_int(&r->r_refs, 1); 787 TRACEINDEX(refcnt, r->r_traceidx, r, 0, +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 TRACEINDEX(refcnt, r->r_traceidx, r, refs - 1, +1); 798 (void)refs; 799 } 800 801 int 802 refcnt_rele(struct refcnt *r) 803 { 804 u_int refs; 805 806 membar_exit_before_atomic(); 807 refs = atomic_dec_int_nv(&r->r_refs); 808 KASSERT(refs != ~0); 809 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 810 if (refs == 0) { 811 membar_enter_after_atomic(); 812 return (1); 813 } 814 return (0); 815 } 816 817 void 818 refcnt_rele_wake(struct refcnt *r) 819 { 820 if (refcnt_rele(r)) 821 wakeup_one(r); 822 } 823 824 void 825 refcnt_finalize(struct refcnt *r, const char *wmesg) 826 { 827 u_int refs; 828 829 membar_exit_before_atomic(); 830 refs = atomic_dec_int_nv(&r->r_refs); 831 KASSERT(refs != ~0); 832 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 833 while (refs) { 834 sleep_setup(r, PWAIT, wmesg); 835 refs = atomic_load_int(&r->r_refs); 836 sleep_finish(0, refs); 837 } 838 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 839 /* Order subsequent loads and stores after refs == 0 load. */ 840 membar_sync(); 841 } 842 843 int 844 refcnt_shared(struct refcnt *r) 845 { 846 u_int refs; 847 848 refs = atomic_load_int(&r->r_refs); 849 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 850 return (refs > 1); 851 } 852 853 unsigned int 854 refcnt_read(struct refcnt *r) 855 { 856 u_int refs; 857 858 refs = atomic_load_int(&r->r_refs); 859 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 860 return (refs); 861 } 862 863 void 864 cond_init(struct cond *c) 865 { 866 atomic_store_int(&c->c_wait, 1); 867 } 868 869 void 870 cond_signal(struct cond *c) 871 { 872 atomic_store_int(&c->c_wait, 0); 873 874 wakeup_one(c); 875 } 876 877 void 878 cond_wait(struct cond *c, const char *wmesg) 879 { 880 unsigned int wait; 881 882 wait = atomic_load_int(&c->c_wait); 883 while (wait) { 884 sleep_setup(c, PWAIT, wmesg); 885 wait = atomic_load_int(&c->c_wait); 886 sleep_finish(0, wait); 887 } 888 } 889