1 /* $OpenBSD: kern_synch.c,v 1.210 2024/11/04 22:41:50 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(struct proc *); 66 int thrsleep(struct proc *, struct sys___thrsleep_args *); 67 int thrsleep_unlock(void *); 68 69 extern void proc_stop(struct proc *p, int); 70 71 /* 72 * We're only looking at 7 bits of the address; everything is 73 * aligned to 4, lots of things are aligned to greater powers 74 * of 2. Shift right by 8, i.e. drop the bottom 256 worth. 75 */ 76 #define TABLESIZE 128 77 #define LOOKUP(x) (((long)(x) >> 8) & (TABLESIZE - 1)) 78 TAILQ_HEAD(slpque,proc) slpque[TABLESIZE]; 79 80 void 81 sleep_queue_init(void) 82 { 83 int i; 84 85 for (i = 0; i < TABLESIZE; i++) 86 TAILQ_INIT(&slpque[i]); 87 } 88 89 /* 90 * Global sleep channel for threads that do not want to 91 * receive wakeup(9) broadcasts. 92 */ 93 int nowake; 94 95 /* 96 * During autoconfiguration or after a panic, a sleep will simply 97 * lower the priority briefly to allow interrupts, then return. 98 * The priority to be used (safepri) is machine-dependent, thus this 99 * value is initialized and maintained in the machine-dependent layers. 100 * This priority will typically be 0, or the lowest priority 101 * that is safe for use on the interrupt stack; it can be made 102 * higher to block network software interrupts after panics. 103 */ 104 extern int safepri; 105 106 /* 107 * General sleep call. Suspends the current process until a wakeup is 108 * performed on the specified identifier. The process will then be made 109 * runnable with the specified priority. Sleeps at most timo/hz seconds 110 * (0 means no timeout). If pri includes PCATCH flag, signals are checked 111 * before and after sleeping, else signals are not checked. Returns 0 if 112 * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a 113 * signal needs to be delivered, ERESTART is returned if the current system 114 * call should be restarted if possible, and EINTR is returned if the system 115 * call should be interrupted by the signal (return EINTR). 116 */ 117 int 118 tsleep(const volatile void *ident, int priority, const char *wmesg, int timo) 119 { 120 #ifdef MULTIPROCESSOR 121 int hold_count; 122 #endif 123 124 KASSERT((priority & ~(PRIMASK | PCATCH)) == 0); 125 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 126 127 #ifdef MULTIPROCESSOR 128 KASSERT(ident == &nowake || timo || _kernel_lock_held()); 129 #endif 130 131 #ifdef DDB 132 if (cold == 2) 133 db_stack_dump(); 134 #endif 135 if (cold || panicstr) { 136 int s; 137 /* 138 * After a panic, or during autoconfiguration, 139 * just give interrupts a chance, then just return; 140 * don't run any other procs or panic below, 141 * in case this is the idle process and already asleep. 142 */ 143 s = splhigh(); 144 splx(safepri); 145 #ifdef MULTIPROCESSOR 146 if (_kernel_lock_held()) { 147 hold_count = __mp_release_all(&kernel_lock); 148 __mp_acquire_count(&kernel_lock, hold_count); 149 } 150 #endif 151 splx(s); 152 return (0); 153 } 154 155 sleep_setup(ident, priority, wmesg); 156 return sleep_finish(timo, 1); 157 } 158 159 int 160 tsleep_nsec(const volatile void *ident, int priority, const char *wmesg, 161 uint64_t nsecs) 162 { 163 uint64_t to_ticks; 164 165 if (nsecs == INFSLP) 166 return tsleep(ident, priority, wmesg, 0); 167 #ifdef DIAGNOSTIC 168 if (nsecs == 0) { 169 log(LOG_WARNING, 170 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 171 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 172 wmesg); 173 } 174 #endif 175 /* 176 * We want to sleep at least nsecs nanoseconds worth of ticks. 177 * 178 * - Clamp nsecs to prevent arithmetic overflow. 179 * 180 * - Round nsecs up to account for any nanoseconds that do not 181 * divide evenly into tick_nsec, otherwise we'll lose them to 182 * integer division in the next step. We add (tick_nsec - 1) 183 * to keep from introducing a spurious tick if there are no 184 * such nanoseconds, i.e. nsecs % tick_nsec == 0. 185 * 186 * - Divide the rounded value to a count of ticks. We divide 187 * by (tick_nsec + 1) to discard the extra tick introduced if, 188 * before rounding, nsecs % tick_nsec == 1. 189 * 190 * - Finally, add a tick to the result. We need to wait out 191 * the current tick before we can begin counting our interval, 192 * as we do not know how much time has elapsed since the 193 * current tick began. 194 */ 195 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 196 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 197 if (to_ticks > INT_MAX) 198 to_ticks = INT_MAX; 199 return tsleep(ident, priority, wmesg, (int)to_ticks); 200 } 201 202 /* 203 * Same as tsleep, but if we have a mutex provided, then once we've 204 * entered the sleep queue we drop the mutex. After sleeping we re-lock. 205 */ 206 int 207 msleep(const volatile void *ident, struct mutex *mtx, int priority, 208 const char *wmesg, int timo) 209 { 210 int error, spl; 211 #ifdef MULTIPROCESSOR 212 int hold_count; 213 #endif 214 215 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 216 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 217 KASSERT(mtx != NULL); 218 219 #ifdef DDB 220 if (cold == 2) 221 db_stack_dump(); 222 #endif 223 if (cold || panicstr) { 224 /* 225 * After a panic, or during autoconfiguration, 226 * just give interrupts a chance, then just return; 227 * don't run any other procs or panic below, 228 * in case this is the idle process and already asleep. 229 */ 230 spl = MUTEX_OLDIPL(mtx); 231 MUTEX_OLDIPL(mtx) = safepri; 232 mtx_leave(mtx); 233 #ifdef MULTIPROCESSOR 234 if (_kernel_lock_held()) { 235 hold_count = __mp_release_all(&kernel_lock); 236 __mp_acquire_count(&kernel_lock, hold_count); 237 } 238 #endif 239 if ((priority & PNORELOCK) == 0) { 240 mtx_enter(mtx); 241 MUTEX_OLDIPL(mtx) = spl; 242 } else 243 splx(spl); 244 return (0); 245 } 246 247 sleep_setup(ident, priority, wmesg); 248 249 mtx_leave(mtx); 250 /* signal may stop the process, release mutex before that */ 251 error = sleep_finish(timo, 1); 252 253 if ((priority & PNORELOCK) == 0) 254 mtx_enter(mtx); 255 256 return error; 257 } 258 259 int 260 msleep_nsec(const volatile void *ident, struct mutex *mtx, int priority, 261 const char *wmesg, uint64_t nsecs) 262 { 263 uint64_t to_ticks; 264 265 if (nsecs == INFSLP) 266 return msleep(ident, mtx, priority, wmesg, 0); 267 #ifdef DIAGNOSTIC 268 if (nsecs == 0) { 269 log(LOG_WARNING, 270 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 271 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 272 wmesg); 273 } 274 #endif 275 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 276 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 277 if (to_ticks > INT_MAX) 278 to_ticks = INT_MAX; 279 return msleep(ident, mtx, priority, wmesg, (int)to_ticks); 280 } 281 282 /* 283 * Same as tsleep, but if we have a rwlock provided, then once we've 284 * entered the sleep queue we drop the it. After sleeping we re-lock. 285 */ 286 int 287 rwsleep(const volatile void *ident, struct rwlock *rwl, int priority, 288 const char *wmesg, int timo) 289 { 290 int error, status; 291 292 KASSERT((priority & ~(PRIMASK | PCATCH | PNORELOCK)) == 0); 293 KASSERT(ident != &nowake || ISSET(priority, PCATCH) || timo != 0); 294 KASSERT(ident != rwl); 295 rw_assert_anylock(rwl); 296 status = rw_status(rwl); 297 298 sleep_setup(ident, priority, wmesg); 299 300 rw_exit(rwl); 301 /* signal may stop the process, release rwlock before that */ 302 error = sleep_finish(timo, 1); 303 304 if ((priority & PNORELOCK) == 0) 305 rw_enter(rwl, status); 306 307 return error; 308 } 309 310 int 311 rwsleep_nsec(const volatile void *ident, struct rwlock *rwl, int priority, 312 const char *wmesg, uint64_t nsecs) 313 { 314 uint64_t to_ticks; 315 316 if (nsecs == INFSLP) 317 return rwsleep(ident, rwl, priority, wmesg, 0); 318 #ifdef DIAGNOSTIC 319 if (nsecs == 0) { 320 log(LOG_WARNING, 321 "%s: %s[%d]: %s: trying to sleep zero nanoseconds\n", 322 __func__, curproc->p_p->ps_comm, curproc->p_p->ps_pid, 323 wmesg); 324 } 325 #endif 326 nsecs = MIN(nsecs, UINT64_MAX - tick_nsec); 327 to_ticks = (nsecs + tick_nsec - 1) / (tick_nsec + 1) + 1; 328 if (to_ticks > INT_MAX) 329 to_ticks = INT_MAX; 330 return rwsleep(ident, rwl, priority, wmesg, (int)to_ticks); 331 } 332 333 void 334 sleep_setup(const volatile void *ident, int prio, const char *wmesg) 335 { 336 struct proc *p = curproc; 337 338 #ifdef DIAGNOSTIC 339 if (p->p_flag & P_CANTSLEEP) 340 panic("sleep: %s failed insomnia", p->p_p->ps_comm); 341 if (ident == NULL) 342 panic("tsleep: no ident"); 343 if (p->p_stat != SONPROC) 344 panic("tsleep: not SONPROC"); 345 #endif 346 /* exiting processes are not allowed to catch signals */ 347 if (p->p_flag & P_WEXIT) 348 CLR(prio, PCATCH); 349 350 SCHED_LOCK(); 351 352 TRACEPOINT(sched, sleep, NULL); 353 354 p->p_wchan = ident; 355 p->p_wmesg = wmesg; 356 p->p_slptime = 0; 357 p->p_slppri = prio & PRIMASK; 358 atomic_setbits_int(&p->p_flag, P_WSLEEP); 359 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); 360 if (prio & PCATCH) 361 atomic_setbits_int(&p->p_flag, P_SINTR); 362 p->p_stat = SSLEEP; 363 364 SCHED_UNLOCK(); 365 } 366 367 int 368 sleep_finish(int timo, int do_sleep) 369 { 370 struct proc *p = curproc; 371 int catch, error = 0, error1 = 0; 372 373 catch = p->p_flag & P_SINTR; 374 375 if (timo != 0) { 376 KASSERT((p->p_flag & P_TIMEOUT) == 0); 377 timeout_add(&p->p_sleep_to, timo); 378 } 379 380 if (catch != 0) { 381 /* 382 * We put ourselves on the sleep queue and start our 383 * timeout before calling sleep_signal_check(), as we could 384 * stop there, and a wakeup or a SIGCONT (or both) could 385 * occur while we were stopped. A SIGCONT would cause 386 * us to be marked as SSLEEP without resuming us, thus 387 * we must be ready for sleep when sleep_signal_check() is 388 * called. 389 */ 390 if ((error = sleep_signal_check(p)) != 0) { 391 catch = 0; 392 do_sleep = 0; 393 } 394 } 395 396 SCHED_LOCK(); 397 /* 398 * A few checks need to happen before going to sleep: 399 * - If the wakeup happens while going to sleep, p->p_wchan 400 * will be NULL. In that case unwind immediately but still 401 * check for possible signals and timeouts. 402 * - If the sleep is aborted call unsleep and take us of the 403 * sleep queue. 404 * - If requested to stop force a switch even if the sleep 405 * condition got cleared. 406 */ 407 if (p->p_wchan == NULL) 408 do_sleep = 0; 409 if (do_sleep == 0) 410 unsleep(p); 411 if (p->p_stat == SSTOP) 412 do_sleep = 1; 413 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 414 415 if (do_sleep) { 416 KASSERT(p->p_stat == SSLEEP || p->p_stat == SSTOP); 417 p->p_ru.ru_nvcsw++; 418 mi_switch(); 419 } else { 420 KASSERT(p->p_stat == SONPROC || p->p_stat == SSLEEP); 421 p->p_stat = SONPROC; 422 } 423 424 #ifdef DIAGNOSTIC 425 if (p->p_stat != SONPROC) 426 panic("sleep_finish !SONPROC"); 427 #endif 428 429 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 430 SCHED_UNLOCK(); 431 432 /* 433 * Even though this belongs to the signal handling part of sleep, 434 * we need to clear it before the ktrace. 435 */ 436 atomic_clearbits_int(&p->p_flag, P_SINTR); 437 438 if (timo != 0) { 439 if (p->p_flag & P_TIMEOUT) { 440 error1 = EWOULDBLOCK; 441 } else { 442 /* This can sleep. It must not use timeouts. */ 443 timeout_del_barrier(&p->p_sleep_to); 444 } 445 atomic_clearbits_int(&p->p_flag, P_TIMEOUT); 446 } 447 448 /* Check if thread was woken up because of a unwind or signal */ 449 if (catch != 0) 450 error = sleep_signal_check(p); 451 452 /* Signal errors are higher priority than timeouts. */ 453 if (error == 0 && error1 != 0) 454 error = error1; 455 456 return error; 457 } 458 459 /* 460 * Check and handle signals and suspensions around a sleep cycle. 461 */ 462 int 463 sleep_signal_check(struct proc *p) 464 { 465 struct sigctx ctx; 466 int err, sig; 467 468 if ((err = single_thread_check(p, 1)) != 0) 469 return err; 470 if ((sig = cursig(p, &ctx, 1)) != 0) { 471 if (ctx.sig_stop) { 472 SCHED_LOCK(); 473 proc_stop(p, 0); 474 SCHED_UNLOCK(); 475 } else if (ctx.sig_intr) 476 return EINTR; 477 else 478 return ERESTART; 479 } 480 return 0; 481 } 482 483 int 484 wakeup_proc(struct proc *p, int flags) 485 { 486 int awakened = 0; 487 488 SCHED_ASSERT_LOCKED(); 489 490 if (p->p_wchan != NULL) { 491 awakened = 1; 492 if (flags) 493 atomic_setbits_int(&p->p_flag, flags); 494 #ifdef DIAGNOSTIC 495 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 496 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 497 #endif 498 unsleep(p); 499 if (p->p_stat == SSLEEP) 500 setrunnable(p); 501 } 502 503 return awakened; 504 } 505 506 507 /* 508 * Implement timeout for tsleep. 509 * If process hasn't been awakened (wchan non-zero), 510 * set timeout flag and undo the sleep. If proc 511 * is stopped, just unsleep so it will remain stopped. 512 */ 513 void 514 endtsleep(void *arg) 515 { 516 struct proc *p = arg; 517 518 SCHED_LOCK(); 519 wakeup_proc(p, P_TIMEOUT); 520 SCHED_UNLOCK(); 521 } 522 523 /* 524 * Remove a process from its wait queue 525 */ 526 void 527 unsleep(struct proc *p) 528 { 529 SCHED_ASSERT_LOCKED(); 530 531 if (p->p_wchan != NULL) { 532 TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); 533 p->p_wchan = NULL; 534 p->p_wmesg = NULL; 535 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 536 p->p_p->ps_pid); 537 } 538 } 539 540 /* 541 * Make a number of processes sleeping on the specified identifier runnable. 542 */ 543 void 544 wakeup_n(const volatile void *ident, int n) 545 { 546 struct slpque *qp, wakeq; 547 struct proc *p; 548 struct proc *pnext; 549 550 TAILQ_INIT(&wakeq); 551 552 SCHED_LOCK(); 553 qp = &slpque[LOOKUP(ident)]; 554 for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { 555 pnext = TAILQ_NEXT(p, p_runq); 556 #ifdef DIAGNOSTIC 557 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 558 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 559 #endif 560 KASSERT(p->p_wchan != NULL); 561 if (p->p_wchan == ident) { 562 TAILQ_REMOVE(qp, p, p_runq); 563 p->p_wchan = NULL; 564 p->p_wmesg = NULL; 565 TAILQ_INSERT_TAIL(&wakeq, p, p_runq); 566 --n; 567 } 568 } 569 while ((p = TAILQ_FIRST(&wakeq))) { 570 TAILQ_REMOVE(&wakeq, p, p_runq); 571 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 572 p->p_p->ps_pid); 573 if (p->p_stat == SSLEEP) 574 setrunnable(p); 575 } 576 SCHED_UNLOCK(); 577 } 578 579 /* 580 * Make all processes sleeping on the specified identifier runnable. 581 */ 582 void 583 wakeup(const volatile void *chan) 584 { 585 wakeup_n(chan, -1); 586 } 587 588 int 589 sys_sched_yield(struct proc *p, void *v, register_t *retval) 590 { 591 struct proc *q; 592 uint8_t newprio; 593 594 /* 595 * If one of the threads of a multi-threaded process called 596 * sched_yield(2), drop its priority to ensure its siblings 597 * can make some progress. 598 */ 599 mtx_enter(&p->p_p->ps_mtx); 600 newprio = p->p_usrpri; 601 TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) 602 newprio = max(newprio, q->p_runpri); 603 mtx_leave(&p->p_p->ps_mtx); 604 605 SCHED_LOCK(); 606 setrunqueue(p->p_cpu, p, newprio); 607 p->p_ru.ru_nvcsw++; 608 mi_switch(); 609 SCHED_UNLOCK(); 610 611 return (0); 612 } 613 614 int 615 thrsleep_unlock(void *lock) 616 { 617 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 618 _atomic_lock_t *atomiclock = lock; 619 620 if (!lock) 621 return 0; 622 623 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 624 } 625 626 struct tslpentry { 627 TAILQ_ENTRY(tslpentry) tslp_link; 628 long tslp_ident; 629 }; 630 631 /* thrsleep queue shared between processes */ 632 static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 633 static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 634 635 int 636 thrsleep(struct proc *p, struct sys___thrsleep_args *v) 637 { 638 struct sys___thrsleep_args /* { 639 syscallarg(const volatile void *) ident; 640 syscallarg(clockid_t) clock_id; 641 syscallarg(const struct timespec *) tp; 642 syscallarg(void *) lock; 643 syscallarg(const int *) abort; 644 } */ *uap = v; 645 long ident = (long)SCARG(uap, ident); 646 struct tslpentry entry; 647 struct tslpqueue *queue; 648 struct rwlock *qlock; 649 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 650 void *lock = SCARG(uap, lock); 651 uint64_t nsecs = INFSLP; 652 int abort = 0, error; 653 clockid_t clock_id = SCARG(uap, clock_id); 654 655 if (ident == 0) 656 return (EINVAL); 657 if (tsp != NULL) { 658 struct timespec now; 659 660 if ((error = clock_gettime(p, clock_id, &now))) 661 return (error); 662 #ifdef KTRACE 663 if (KTRPOINT(p, KTR_STRUCT)) 664 ktrabstimespec(p, tsp); 665 #endif 666 667 if (timespeccmp(tsp, &now, <=)) { 668 /* already passed: still do the unlock */ 669 if ((error = thrsleep_unlock(lock))) 670 return (error); 671 return (EWOULDBLOCK); 672 } 673 674 timespecsub(tsp, &now, tsp); 675 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 676 } 677 678 if (ident == -1) { 679 queue = &thrsleep_queue; 680 qlock = &thrsleep_lock; 681 } else { 682 queue = &p->p_p->ps_tslpqueue; 683 qlock = &p->p_p->ps_lock; 684 } 685 686 /* Interlock with wakeup. */ 687 entry.tslp_ident = ident; 688 rw_enter_write(qlock); 689 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 690 rw_exit_write(qlock); 691 692 error = thrsleep_unlock(lock); 693 694 if (error == 0 && SCARG(uap, abort) != NULL) 695 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 696 697 rw_enter_write(qlock); 698 if (error != 0) 699 goto out; 700 if (abort != 0) { 701 error = EINTR; 702 goto out; 703 } 704 if (entry.tslp_ident != 0) { 705 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 706 nsecs); 707 } 708 709 out: 710 if (entry.tslp_ident != 0) 711 TAILQ_REMOVE(queue, &entry, tslp_link); 712 rw_exit_write(qlock); 713 714 if (error == ERESTART) 715 error = ECANCELED; 716 717 return (error); 718 719 } 720 721 int 722 sys___thrsleep(struct proc *p, void *v, register_t *retval) 723 { 724 struct sys___thrsleep_args /* { 725 syscallarg(const volatile void *) ident; 726 syscallarg(clockid_t) clock_id; 727 syscallarg(struct timespec *) tp; 728 syscallarg(void *) lock; 729 syscallarg(const int *) abort; 730 } */ *uap = v; 731 struct timespec ts; 732 int error; 733 734 if (SCARG(uap, tp) != NULL) { 735 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 736 *retval = error; 737 return 0; 738 } 739 if (!timespecisvalid(&ts)) { 740 *retval = EINVAL; 741 return 0; 742 } 743 SCARG(uap, tp) = &ts; 744 } 745 746 *retval = thrsleep(p, uap); 747 return 0; 748 } 749 750 int 751 sys___thrwakeup(struct proc *p, void *v, register_t *retval) 752 { 753 struct sys___thrwakeup_args /* { 754 syscallarg(const volatile void *) ident; 755 syscallarg(int) n; 756 } */ *uap = v; 757 struct tslpentry *entry, *tmp; 758 struct tslpqueue *queue; 759 struct rwlock *qlock; 760 long ident = (long)SCARG(uap, ident); 761 int n = SCARG(uap, n); 762 int found = 0; 763 764 if (ident == 0) 765 *retval = EINVAL; 766 else { 767 if (ident == -1) { 768 queue = &thrsleep_queue; 769 qlock = &thrsleep_lock; 770 /* 771 * Wake up all waiters with ident -1. This is needed 772 * because ident -1 can be shared by multiple userspace 773 * lock state machines concurrently. The implementation 774 * has no way to direct the wakeup to a particular 775 * state machine. 776 */ 777 n = 0; 778 } else { 779 queue = &p->p_p->ps_tslpqueue; 780 qlock = &p->p_p->ps_lock; 781 } 782 783 rw_enter_write(qlock); 784 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 785 if (entry->tslp_ident == ident) { 786 TAILQ_REMOVE(queue, entry, tslp_link); 787 entry->tslp_ident = 0; 788 wakeup_one(entry); 789 if (++found == n) 790 break; 791 } 792 } 793 rw_exit_write(qlock); 794 795 if (ident == -1) 796 *retval = 0; 797 else 798 *retval = found ? 0 : ESRCH; 799 } 800 801 return (0); 802 } 803 804 void 805 refcnt_init(struct refcnt *r) 806 { 807 refcnt_init_trace(r, 0); 808 } 809 810 void 811 refcnt_init_trace(struct refcnt *r, int idx) 812 { 813 r->r_traceidx = idx; 814 atomic_store_int(&r->r_refs, 1); 815 TRACEINDEX(refcnt, r->r_traceidx, r, 0, +1); 816 } 817 818 void 819 refcnt_take(struct refcnt *r) 820 { 821 u_int refs; 822 823 refs = atomic_inc_int_nv(&r->r_refs); 824 KASSERT(refs != 0); 825 TRACEINDEX(refcnt, r->r_traceidx, r, refs - 1, +1); 826 (void)refs; 827 } 828 829 int 830 refcnt_rele(struct refcnt *r) 831 { 832 u_int refs; 833 834 membar_exit_before_atomic(); 835 refs = atomic_dec_int_nv(&r->r_refs); 836 KASSERT(refs != ~0); 837 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 838 if (refs == 0) { 839 membar_enter_after_atomic(); 840 return (1); 841 } 842 return (0); 843 } 844 845 void 846 refcnt_rele_wake(struct refcnt *r) 847 { 848 if (refcnt_rele(r)) 849 wakeup_one(r); 850 } 851 852 void 853 refcnt_finalize(struct refcnt *r, const char *wmesg) 854 { 855 u_int refs; 856 857 membar_exit_before_atomic(); 858 refs = atomic_dec_int_nv(&r->r_refs); 859 KASSERT(refs != ~0); 860 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 861 while (refs) { 862 sleep_setup(r, PWAIT, wmesg); 863 refs = atomic_load_int(&r->r_refs); 864 sleep_finish(0, refs); 865 } 866 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 867 /* Order subsequent loads and stores after refs == 0 load. */ 868 membar_sync(); 869 } 870 871 int 872 refcnt_shared(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 > 1); 879 } 880 881 unsigned int 882 refcnt_read(struct refcnt *r) 883 { 884 u_int refs; 885 886 refs = atomic_load_int(&r->r_refs); 887 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 888 return (refs); 889 } 890 891 void 892 cond_init(struct cond *c) 893 { 894 atomic_store_int(&c->c_wait, 1); 895 } 896 897 void 898 cond_signal(struct cond *c) 899 { 900 atomic_store_int(&c->c_wait, 0); 901 902 wakeup_one(c); 903 } 904 905 void 906 cond_wait(struct cond *c, const char *wmesg) 907 { 908 unsigned int wait; 909 910 wait = atomic_load_int(&c->c_wait); 911 while (wait) { 912 sleep_setup(c, PWAIT, wmesg); 913 wait = atomic_load_int(&c->c_wait); 914 sleep_finish(0, wait); 915 } 916 } 917