1 /* $OpenBSD: kern_synch.c,v 1.203 2024/05/20 10:32:20 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 /* exiting processes are not allowed to catch signals */ 346 if (p->p_flag & P_WEXIT) 347 CLR(prio, PCATCH); 348 349 SCHED_LOCK(s); 350 351 TRACEPOINT(sched, sleep, NULL); 352 353 p->p_wchan = ident; 354 p->p_wmesg = wmesg; 355 p->p_slptime = 0; 356 p->p_slppri = prio & PRIMASK; 357 atomic_setbits_int(&p->p_flag, P_WSLEEP); 358 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); 359 if (prio & PCATCH) 360 atomic_setbits_int(&p->p_flag, P_SINTR); 361 p->p_stat = SSLEEP; 362 363 SCHED_UNLOCK(s); 364 } 365 366 int 367 sleep_finish(int timo, int do_sleep) 368 { 369 struct proc *p = curproc; 370 int s, catch, error = 0, error1 = 0; 371 372 catch = p->p_flag & P_SINTR; 373 374 if (timo != 0) { 375 KASSERT((p->p_flag & P_TIMEOUT) == 0); 376 timeout_add(&p->p_sleep_to, timo); 377 } 378 379 if (catch != 0) { 380 /* 381 * We put ourselves on the sleep queue and start our 382 * timeout before calling sleep_signal_check(), as we could 383 * stop there, and a wakeup or a SIGCONT (or both) could 384 * occur while we were stopped. A SIGCONT would cause 385 * us to be marked as SSLEEP without resuming us, thus 386 * we must be ready for sleep when sleep_signal_check() is 387 * called. 388 */ 389 if ((error = sleep_signal_check()) != 0) { 390 catch = 0; 391 do_sleep = 0; 392 } 393 } 394 395 SCHED_LOCK(s); 396 /* 397 * If the wakeup happens while going to sleep, p->p_wchan 398 * will be NULL. In that case unwind immediately but still 399 * check for possible signals and timeouts. 400 */ 401 if (p->p_wchan == NULL) 402 do_sleep = 0; 403 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 404 405 if (do_sleep) { 406 KASSERT(p->p_stat == SSLEEP || p->p_stat == SSTOP); 407 p->p_ru.ru_nvcsw++; 408 mi_switch(); 409 } else { 410 KASSERT(p->p_stat == SONPROC || p->p_stat == SSLEEP || 411 p->p_stat == SSTOP); 412 unsleep(p); 413 p->p_stat = SONPROC; 414 } 415 416 #ifdef DIAGNOSTIC 417 if (p->p_stat != SONPROC) 418 panic("sleep_finish !SONPROC"); 419 #endif 420 421 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 422 SCHED_UNLOCK(s); 423 424 /* 425 * Even though this belongs to the signal handling part of sleep, 426 * we need to clear it before the ktrace. 427 */ 428 atomic_clearbits_int(&p->p_flag, P_SINTR); 429 430 if (timo != 0) { 431 if (p->p_flag & P_TIMEOUT) { 432 error1 = EWOULDBLOCK; 433 } else { 434 /* This can sleep. It must not use timeouts. */ 435 timeout_del_barrier(&p->p_sleep_to); 436 } 437 atomic_clearbits_int(&p->p_flag, P_TIMEOUT); 438 } 439 440 /* Check if thread was woken up because of a unwind or signal */ 441 if (catch != 0) 442 error = sleep_signal_check(); 443 444 /* Signal errors are higher priority than timeouts. */ 445 if (error == 0 && error1 != 0) 446 error = error1; 447 448 return error; 449 } 450 451 /* 452 * Check and handle signals and suspensions around a sleep cycle. 453 */ 454 int 455 sleep_signal_check(void) 456 { 457 struct proc *p = curproc; 458 struct sigctx ctx; 459 int err, sig; 460 461 if ((err = single_thread_check(p, 1)) != 0) 462 return err; 463 if ((sig = cursig(p, &ctx)) != 0) { 464 if (ctx.sig_intr) 465 return EINTR; 466 else 467 return ERESTART; 468 } 469 return 0; 470 } 471 472 int 473 wakeup_proc(struct proc *p, int flags) 474 { 475 int awakened = 0; 476 477 SCHED_ASSERT_LOCKED(); 478 479 if (p->p_wchan != NULL) { 480 awakened = 1; 481 if (flags) 482 atomic_setbits_int(&p->p_flag, flags); 483 #ifdef DIAGNOSTIC 484 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 485 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 486 #endif 487 unsleep(p); 488 if (p->p_stat == SSLEEP) 489 setrunnable(p); 490 } 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 wakeup_proc(p, P_TIMEOUT); 510 SCHED_UNLOCK(s); 511 } 512 513 /* 514 * Remove a process from its wait queue 515 */ 516 void 517 unsleep(struct proc *p) 518 { 519 SCHED_ASSERT_LOCKED(); 520 521 if (p->p_wchan != NULL) { 522 TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); 523 p->p_wchan = NULL; 524 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 525 p->p_p->ps_pid); 526 } 527 } 528 529 /* 530 * Make a number of processes sleeping on the specified identifier runnable. 531 */ 532 void 533 wakeup_n(const volatile void *ident, int n) 534 { 535 struct slpque *qp, wakeq; 536 struct proc *p; 537 struct proc *pnext; 538 int s; 539 540 TAILQ_INIT(&wakeq); 541 542 SCHED_LOCK(s); 543 qp = &slpque[LOOKUP(ident)]; 544 for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { 545 pnext = TAILQ_NEXT(p, p_runq); 546 #ifdef DIAGNOSTIC 547 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 548 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 549 #endif 550 KASSERT(p->p_wchan != NULL); 551 if (p->p_wchan == ident) { 552 TAILQ_REMOVE(qp, p, p_runq); 553 p->p_wchan = NULL; 554 TAILQ_INSERT_TAIL(&wakeq, p, p_runq); 555 --n; 556 } 557 } 558 while ((p = TAILQ_FIRST(&wakeq))) { 559 TAILQ_REMOVE(&wakeq, p, p_runq); 560 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 561 p->p_p->ps_pid); 562 if (p->p_stat == SSLEEP) 563 setrunnable(p); 564 } 565 SCHED_UNLOCK(s); 566 } 567 568 /* 569 * Make all processes sleeping on the specified identifier runnable. 570 */ 571 void 572 wakeup(const volatile void *chan) 573 { 574 wakeup_n(chan, -1); 575 } 576 577 int 578 sys_sched_yield(struct proc *p, void *v, register_t *retval) 579 { 580 struct proc *q; 581 uint8_t newprio; 582 int s; 583 584 /* 585 * If one of the threads of a multi-threaded process called 586 * sched_yield(2), drop its priority to ensure its siblings 587 * can make some progress. 588 */ 589 mtx_enter(&p->p_p->ps_mtx); 590 newprio = p->p_usrpri; 591 TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) 592 newprio = max(newprio, q->p_runpri); 593 mtx_leave(&p->p_p->ps_mtx); 594 595 SCHED_LOCK(s); 596 setrunqueue(p->p_cpu, p, newprio); 597 p->p_ru.ru_nvcsw++; 598 mi_switch(); 599 SCHED_UNLOCK(s); 600 601 return (0); 602 } 603 604 int 605 thrsleep_unlock(void *lock) 606 { 607 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 608 _atomic_lock_t *atomiclock = lock; 609 610 if (!lock) 611 return 0; 612 613 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 614 } 615 616 struct tslpentry { 617 TAILQ_ENTRY(tslpentry) tslp_link; 618 long tslp_ident; 619 }; 620 621 /* thrsleep queue shared between processes */ 622 static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 623 static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 624 625 int 626 thrsleep(struct proc *p, struct sys___thrsleep_args *v) 627 { 628 struct sys___thrsleep_args /* { 629 syscallarg(const volatile void *) ident; 630 syscallarg(clockid_t) clock_id; 631 syscallarg(const struct timespec *) tp; 632 syscallarg(void *) lock; 633 syscallarg(const int *) abort; 634 } */ *uap = v; 635 long ident = (long)SCARG(uap, ident); 636 struct tslpentry entry; 637 struct tslpqueue *queue; 638 struct rwlock *qlock; 639 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 640 void *lock = SCARG(uap, lock); 641 uint64_t nsecs = INFSLP; 642 int abort = 0, error; 643 clockid_t clock_id = SCARG(uap, clock_id); 644 645 if (ident == 0) 646 return (EINVAL); 647 if (tsp != NULL) { 648 struct timespec now; 649 650 if ((error = clock_gettime(p, clock_id, &now))) 651 return (error); 652 #ifdef KTRACE 653 if (KTRPOINT(p, KTR_STRUCT)) 654 ktrabstimespec(p, tsp); 655 #endif 656 657 if (timespeccmp(tsp, &now, <=)) { 658 /* already passed: still do the unlock */ 659 if ((error = thrsleep_unlock(lock))) 660 return (error); 661 return (EWOULDBLOCK); 662 } 663 664 timespecsub(tsp, &now, tsp); 665 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 666 } 667 668 if (ident == -1) { 669 queue = &thrsleep_queue; 670 qlock = &thrsleep_lock; 671 } else { 672 queue = &p->p_p->ps_tslpqueue; 673 qlock = &p->p_p->ps_lock; 674 } 675 676 /* Interlock with wakeup. */ 677 entry.tslp_ident = ident; 678 rw_enter_write(qlock); 679 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 680 rw_exit_write(qlock); 681 682 error = thrsleep_unlock(lock); 683 684 if (error == 0 && SCARG(uap, abort) != NULL) 685 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 686 687 rw_enter_write(qlock); 688 if (error != 0) 689 goto out; 690 if (abort != 0) { 691 error = EINTR; 692 goto out; 693 } 694 if (entry.tslp_ident != 0) { 695 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 696 nsecs); 697 } 698 699 out: 700 if (entry.tslp_ident != 0) 701 TAILQ_REMOVE(queue, &entry, tslp_link); 702 rw_exit_write(qlock); 703 704 if (error == ERESTART) 705 error = ECANCELED; 706 707 return (error); 708 709 } 710 711 int 712 sys___thrsleep(struct proc *p, void *v, register_t *retval) 713 { 714 struct sys___thrsleep_args /* { 715 syscallarg(const volatile void *) ident; 716 syscallarg(clockid_t) clock_id; 717 syscallarg(struct timespec *) tp; 718 syscallarg(void *) lock; 719 syscallarg(const int *) abort; 720 } */ *uap = v; 721 struct timespec ts; 722 int error; 723 724 if (SCARG(uap, tp) != NULL) { 725 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 726 *retval = error; 727 return 0; 728 } 729 if (!timespecisvalid(&ts)) { 730 *retval = EINVAL; 731 return 0; 732 } 733 SCARG(uap, tp) = &ts; 734 } 735 736 *retval = thrsleep(p, uap); 737 return 0; 738 } 739 740 int 741 sys___thrwakeup(struct proc *p, void *v, register_t *retval) 742 { 743 struct sys___thrwakeup_args /* { 744 syscallarg(const volatile void *) ident; 745 syscallarg(int) n; 746 } */ *uap = v; 747 struct tslpentry *entry, *tmp; 748 struct tslpqueue *queue; 749 struct rwlock *qlock; 750 long ident = (long)SCARG(uap, ident); 751 int n = SCARG(uap, n); 752 int found = 0; 753 754 if (ident == 0) 755 *retval = EINVAL; 756 else { 757 if (ident == -1) { 758 queue = &thrsleep_queue; 759 qlock = &thrsleep_lock; 760 /* 761 * Wake up all waiters with ident -1. This is needed 762 * because ident -1 can be shared by multiple userspace 763 * lock state machines concurrently. The implementation 764 * has no way to direct the wakeup to a particular 765 * state machine. 766 */ 767 n = 0; 768 } else { 769 queue = &p->p_p->ps_tslpqueue; 770 qlock = &p->p_p->ps_lock; 771 } 772 773 rw_enter_write(qlock); 774 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 775 if (entry->tslp_ident == ident) { 776 TAILQ_REMOVE(queue, entry, tslp_link); 777 entry->tslp_ident = 0; 778 wakeup_one(entry); 779 if (++found == n) 780 break; 781 } 782 } 783 rw_exit_write(qlock); 784 785 if (ident == -1) 786 *retval = 0; 787 else 788 *retval = found ? 0 : ESRCH; 789 } 790 791 return (0); 792 } 793 794 void 795 refcnt_init(struct refcnt *r) 796 { 797 refcnt_init_trace(r, 0); 798 } 799 800 void 801 refcnt_init_trace(struct refcnt *r, int idx) 802 { 803 r->r_traceidx = idx; 804 atomic_store_int(&r->r_refs, 1); 805 TRACEINDEX(refcnt, r->r_traceidx, r, 0, +1); 806 } 807 808 void 809 refcnt_take(struct refcnt *r) 810 { 811 u_int refs; 812 813 refs = atomic_inc_int_nv(&r->r_refs); 814 KASSERT(refs != 0); 815 TRACEINDEX(refcnt, r->r_traceidx, r, refs - 1, +1); 816 (void)refs; 817 } 818 819 int 820 refcnt_rele(struct refcnt *r) 821 { 822 u_int refs; 823 824 membar_exit_before_atomic(); 825 refs = atomic_dec_int_nv(&r->r_refs); 826 KASSERT(refs != ~0); 827 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 828 if (refs == 0) { 829 membar_enter_after_atomic(); 830 return (1); 831 } 832 return (0); 833 } 834 835 void 836 refcnt_rele_wake(struct refcnt *r) 837 { 838 if (refcnt_rele(r)) 839 wakeup_one(r); 840 } 841 842 void 843 refcnt_finalize(struct refcnt *r, const char *wmesg) 844 { 845 u_int refs; 846 847 membar_exit_before_atomic(); 848 refs = atomic_dec_int_nv(&r->r_refs); 849 KASSERT(refs != ~0); 850 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 851 while (refs) { 852 sleep_setup(r, PWAIT, wmesg); 853 refs = atomic_load_int(&r->r_refs); 854 sleep_finish(0, refs); 855 } 856 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 857 /* Order subsequent loads and stores after refs == 0 load. */ 858 membar_sync(); 859 } 860 861 int 862 refcnt_shared(struct refcnt *r) 863 { 864 u_int refs; 865 866 refs = atomic_load_int(&r->r_refs); 867 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 868 return (refs > 1); 869 } 870 871 unsigned int 872 refcnt_read(struct refcnt *r) 873 { 874 u_int refs; 875 876 refs = atomic_load_int(&r->r_refs); 877 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 878 return (refs); 879 } 880 881 void 882 cond_init(struct cond *c) 883 { 884 atomic_store_int(&c->c_wait, 1); 885 } 886 887 void 888 cond_signal(struct cond *c) 889 { 890 atomic_store_int(&c->c_wait, 0); 891 892 wakeup_one(c); 893 } 894 895 void 896 cond_wait(struct cond *c, const char *wmesg) 897 { 898 unsigned int wait; 899 900 wait = atomic_load_int(&c->c_wait); 901 while (wait) { 902 sleep_setup(c, PWAIT, wmesg); 903 wait = atomic_load_int(&c->c_wait); 904 sleep_finish(0, wait); 905 } 906 } 907