1/* $OpenBSD: kern_synch.c,v 1.205 2024/06/03 12:48:25 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 65int sleep_signal_check(void); 66int thrsleep(struct proc *, struct sys___thrsleep_args *); 67int 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)) 76TAILQ_HEAD(slpque,proc) slpque[TABLESIZE]; 77 78void 79sleep_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 */ 91int 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 */ 102extern 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 */ 115int 116tsleep(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 157int 158tsleep_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 */ 204int 205msleep(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 257int 258msleep_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 */ 284int 285rwsleep(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 308int 309rwsleep_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 331void 332sleep_setup(const volatile void *ident, int prio, const char *wmesg) 333{ 334 struct proc *p = curproc; 335 336#ifdef DIAGNOSTIC 337 if (p->p_flag & P_CANTSLEEP) 338 panic("sleep: %s failed insomnia", p->p_p->ps_comm); 339 if (ident == NULL) 340 panic("tsleep: no ident"); 341 if (p->p_stat != SONPROC) 342 panic("tsleep: not SONPROC"); 343#endif 344 /* exiting processes are not allowed to catch signals */ 345 if (p->p_flag & P_WEXIT) 346 CLR(prio, PCATCH); 347 348 SCHED_LOCK(); 349 350 TRACEPOINT(sched, sleep, NULL); 351 352 p->p_wchan = ident; 353 p->p_wmesg = wmesg; 354 p->p_slptime = 0; 355 p->p_slppri = prio & PRIMASK; 356 atomic_setbits_int(&p->p_flag, P_WSLEEP); 357 TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); 358 if (prio & PCATCH) 359 atomic_setbits_int(&p->p_flag, P_SINTR); 360 p->p_stat = SSLEEP; 361 362 SCHED_UNLOCK(); 363} 364 365int 366sleep_finish(int timo, int do_sleep) 367{ 368 struct proc *p = curproc; 369 int catch, error = 0, error1 = 0; 370 371 catch = p->p_flag & P_SINTR; 372 373 if (timo != 0) { 374 KASSERT((p->p_flag & P_TIMEOUT) == 0); 375 timeout_add(&p->p_sleep_to, timo); 376 } 377 378 if (catch != 0) { 379 /* 380 * We put ourselves on the sleep queue and start our 381 * timeout before calling sleep_signal_check(), as we could 382 * stop there, and a wakeup or a SIGCONT (or both) could 383 * occur while we were stopped. A SIGCONT would cause 384 * us to be marked as SSLEEP without resuming us, thus 385 * we must be ready for sleep when sleep_signal_check() is 386 * called. 387 */ 388 if ((error = sleep_signal_check()) != 0) { 389 catch = 0; 390 do_sleep = 0; 391 } 392 } 393 394 SCHED_LOCK(); 395 /* 396 * If the wakeup happens while going to sleep, p->p_wchan 397 * will be NULL. In that case unwind immediately but still 398 * check for possible signals and timeouts. 399 */ 400 if (p->p_wchan == NULL) 401 do_sleep = 0; 402 atomic_clearbits_int(&p->p_flag, P_WSLEEP); 403 404 if (do_sleep) { 405 KASSERT(p->p_stat == SSLEEP || p->p_stat == SSTOP); 406 p->p_ru.ru_nvcsw++; 407 mi_switch(); 408 } else { 409 KASSERT(p->p_stat == SONPROC || p->p_stat == SSLEEP || 410 p->p_stat == SSTOP); 411 unsleep(p); 412 p->p_stat = SONPROC; 413 } 414 415#ifdef DIAGNOSTIC 416 if (p->p_stat != SONPROC) 417 panic("sleep_finish !SONPROC"); 418#endif 419 420 p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; 421 SCHED_UNLOCK(); 422 423 /* 424 * Even though this belongs to the signal handling part of sleep, 425 * we need to clear it before the ktrace. 426 */ 427 atomic_clearbits_int(&p->p_flag, P_SINTR); 428 429 if (timo != 0) { 430 if (p->p_flag & P_TIMEOUT) { 431 error1 = EWOULDBLOCK; 432 } else { 433 /* This can sleep. It must not use timeouts. */ 434 timeout_del_barrier(&p->p_sleep_to); 435 } 436 atomic_clearbits_int(&p->p_flag, P_TIMEOUT); 437 } 438 439 /* Check if thread was woken up because of a unwind or signal */ 440 if (catch != 0) 441 error = sleep_signal_check(); 442 443 /* Signal errors are higher priority than timeouts. */ 444 if (error == 0 && error1 != 0) 445 error = error1; 446 447 return error; 448} 449 450/* 451 * Check and handle signals and suspensions around a sleep cycle. 452 */ 453int 454sleep_signal_check(void) 455{ 456 struct proc *p = curproc; 457 struct sigctx ctx; 458 int err, sig; 459 460 if ((err = single_thread_check(p, 1)) != 0) 461 return err; 462 if ((sig = cursig(p, &ctx)) != 0) { 463 if (ctx.sig_intr) 464 return EINTR; 465 else 466 return ERESTART; 467 } 468 return 0; 469} 470 471int 472wakeup_proc(struct proc *p, int flags) 473{ 474 int awakened = 0; 475 476 SCHED_ASSERT_LOCKED(); 477 478 if (p->p_wchan != NULL) { 479 awakened = 1; 480 if (flags) 481 atomic_setbits_int(&p->p_flag, flags); 482#ifdef DIAGNOSTIC 483 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 484 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 485#endif 486 unsleep(p); 487 if (p->p_stat == SSLEEP) 488 setrunnable(p); 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 */ 501void 502endtsleep(void *arg) 503{ 504 struct proc *p = arg; 505 506 SCHED_LOCK(); 507 wakeup_proc(p, P_TIMEOUT); 508 SCHED_UNLOCK(); 509} 510 511/* 512 * Remove a process from its wait queue 513 */ 514void 515unsleep(struct proc *p) 516{ 517 SCHED_ASSERT_LOCKED(); 518 519 if (p->p_wchan != NULL) { 520 TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); 521 p->p_wchan = NULL; 522 p->p_wmesg = 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 */ 531void 532wakeup_n(const volatile void *ident, int n) 533{ 534 struct slpque *qp, wakeq; 535 struct proc *p; 536 struct proc *pnext; 537 538 TAILQ_INIT(&wakeq); 539 540 SCHED_LOCK(); 541 qp = &slpque[LOOKUP(ident)]; 542 for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { 543 pnext = TAILQ_NEXT(p, p_runq); 544#ifdef DIAGNOSTIC 545 if (p->p_stat != SSLEEP && p->p_stat != SSTOP) 546 panic("thread %d p_stat is %d", p->p_tid, p->p_stat); 547#endif 548 KASSERT(p->p_wchan != NULL); 549 if (p->p_wchan == ident) { 550 TAILQ_REMOVE(qp, p, p_runq); 551 p->p_wchan = NULL; 552 p->p_wmesg = NULL; 553 TAILQ_INSERT_TAIL(&wakeq, p, p_runq); 554 --n; 555 } 556 } 557 while ((p = TAILQ_FIRST(&wakeq))) { 558 TAILQ_REMOVE(&wakeq, p, p_runq); 559 TRACEPOINT(sched, unsleep, p->p_tid + THREAD_PID_OFFSET, 560 p->p_p->ps_pid); 561 if (p->p_stat == SSLEEP) 562 setrunnable(p); 563 } 564 SCHED_UNLOCK(); 565} 566 567/* 568 * Make all processes sleeping on the specified identifier runnable. 569 */ 570void 571wakeup(const volatile void *chan) 572{ 573 wakeup_n(chan, -1); 574} 575 576int 577sys_sched_yield(struct proc *p, void *v, register_t *retval) 578{ 579 struct proc *q; 580 uint8_t newprio; 581 582 /* 583 * If one of the threads of a multi-threaded process called 584 * sched_yield(2), drop its priority to ensure its siblings 585 * can make some progress. 586 */ 587 mtx_enter(&p->p_p->ps_mtx); 588 newprio = p->p_usrpri; 589 TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) 590 newprio = max(newprio, q->p_runpri); 591 mtx_leave(&p->p_p->ps_mtx); 592 593 SCHED_LOCK(); 594 setrunqueue(p->p_cpu, p, newprio); 595 p->p_ru.ru_nvcsw++; 596 mi_switch(); 597 SCHED_UNLOCK(); 598 599 return (0); 600} 601 602int 603thrsleep_unlock(void *lock) 604{ 605 static _atomic_lock_t unlocked = _ATOMIC_LOCK_UNLOCKED; 606 _atomic_lock_t *atomiclock = lock; 607 608 if (!lock) 609 return 0; 610 611 return copyout(&unlocked, atomiclock, sizeof(unlocked)); 612} 613 614struct tslpentry { 615 TAILQ_ENTRY(tslpentry) tslp_link; 616 long tslp_ident; 617}; 618 619/* thrsleep queue shared between processes */ 620static struct tslpqueue thrsleep_queue = TAILQ_HEAD_INITIALIZER(thrsleep_queue); 621static struct rwlock thrsleep_lock = RWLOCK_INITIALIZER("thrsleeplk"); 622 623int 624thrsleep(struct proc *p, struct sys___thrsleep_args *v) 625{ 626 struct sys___thrsleep_args /* { 627 syscallarg(const volatile void *) ident; 628 syscallarg(clockid_t) clock_id; 629 syscallarg(const struct timespec *) tp; 630 syscallarg(void *) lock; 631 syscallarg(const int *) abort; 632 } */ *uap = v; 633 long ident = (long)SCARG(uap, ident); 634 struct tslpentry entry; 635 struct tslpqueue *queue; 636 struct rwlock *qlock; 637 struct timespec *tsp = (struct timespec *)SCARG(uap, tp); 638 void *lock = SCARG(uap, lock); 639 uint64_t nsecs = INFSLP; 640 int abort = 0, error; 641 clockid_t clock_id = SCARG(uap, clock_id); 642 643 if (ident == 0) 644 return (EINVAL); 645 if (tsp != NULL) { 646 struct timespec now; 647 648 if ((error = clock_gettime(p, clock_id, &now))) 649 return (error); 650#ifdef KTRACE 651 if (KTRPOINT(p, KTR_STRUCT)) 652 ktrabstimespec(p, tsp); 653#endif 654 655 if (timespeccmp(tsp, &now, <=)) { 656 /* already passed: still do the unlock */ 657 if ((error = thrsleep_unlock(lock))) 658 return (error); 659 return (EWOULDBLOCK); 660 } 661 662 timespecsub(tsp, &now, tsp); 663 nsecs = MIN(TIMESPEC_TO_NSEC(tsp), MAXTSLP); 664 } 665 666 if (ident == -1) { 667 queue = &thrsleep_queue; 668 qlock = &thrsleep_lock; 669 } else { 670 queue = &p->p_p->ps_tslpqueue; 671 qlock = &p->p_p->ps_lock; 672 } 673 674 /* Interlock with wakeup. */ 675 entry.tslp_ident = ident; 676 rw_enter_write(qlock); 677 TAILQ_INSERT_TAIL(queue, &entry, tslp_link); 678 rw_exit_write(qlock); 679 680 error = thrsleep_unlock(lock); 681 682 if (error == 0 && SCARG(uap, abort) != NULL) 683 error = copyin(SCARG(uap, abort), &abort, sizeof(abort)); 684 685 rw_enter_write(qlock); 686 if (error != 0) 687 goto out; 688 if (abort != 0) { 689 error = EINTR; 690 goto out; 691 } 692 if (entry.tslp_ident != 0) { 693 error = rwsleep_nsec(&entry, qlock, PWAIT|PCATCH, "thrsleep", 694 nsecs); 695 } 696 697out: 698 if (entry.tslp_ident != 0) 699 TAILQ_REMOVE(queue, &entry, tslp_link); 700 rw_exit_write(qlock); 701 702 if (error == ERESTART) 703 error = ECANCELED; 704 705 return (error); 706 707} 708 709int 710sys___thrsleep(struct proc *p, void *v, register_t *retval) 711{ 712 struct sys___thrsleep_args /* { 713 syscallarg(const volatile void *) ident; 714 syscallarg(clockid_t) clock_id; 715 syscallarg(struct timespec *) tp; 716 syscallarg(void *) lock; 717 syscallarg(const int *) abort; 718 } */ *uap = v; 719 struct timespec ts; 720 int error; 721 722 if (SCARG(uap, tp) != NULL) { 723 if ((error = copyin(SCARG(uap, tp), &ts, sizeof(ts)))) { 724 *retval = error; 725 return 0; 726 } 727 if (!timespecisvalid(&ts)) { 728 *retval = EINVAL; 729 return 0; 730 } 731 SCARG(uap, tp) = &ts; 732 } 733 734 *retval = thrsleep(p, uap); 735 return 0; 736} 737 738int 739sys___thrwakeup(struct proc *p, void *v, register_t *retval) 740{ 741 struct sys___thrwakeup_args /* { 742 syscallarg(const volatile void *) ident; 743 syscallarg(int) n; 744 } */ *uap = v; 745 struct tslpentry *entry, *tmp; 746 struct tslpqueue *queue; 747 struct rwlock *qlock; 748 long ident = (long)SCARG(uap, ident); 749 int n = SCARG(uap, n); 750 int found = 0; 751 752 if (ident == 0) 753 *retval = EINVAL; 754 else { 755 if (ident == -1) { 756 queue = &thrsleep_queue; 757 qlock = &thrsleep_lock; 758 /* 759 * Wake up all waiters with ident -1. This is needed 760 * because ident -1 can be shared by multiple userspace 761 * lock state machines concurrently. The implementation 762 * has no way to direct the wakeup to a particular 763 * state machine. 764 */ 765 n = 0; 766 } else { 767 queue = &p->p_p->ps_tslpqueue; 768 qlock = &p->p_p->ps_lock; 769 } 770 771 rw_enter_write(qlock); 772 TAILQ_FOREACH_SAFE(entry, queue, tslp_link, tmp) { 773 if (entry->tslp_ident == ident) { 774 TAILQ_REMOVE(queue, entry, tslp_link); 775 entry->tslp_ident = 0; 776 wakeup_one(entry); 777 if (++found == n) 778 break; 779 } 780 } 781 rw_exit_write(qlock); 782 783 if (ident == -1) 784 *retval = 0; 785 else 786 *retval = found ? 0 : ESRCH; 787 } 788 789 return (0); 790} 791 792void 793refcnt_init(struct refcnt *r) 794{ 795 refcnt_init_trace(r, 0); 796} 797 798void 799refcnt_init_trace(struct refcnt *r, int idx) 800{ 801 r->r_traceidx = idx; 802 atomic_store_int(&r->r_refs, 1); 803 TRACEINDEX(refcnt, r->r_traceidx, r, 0, +1); 804} 805 806void 807refcnt_take(struct refcnt *r) 808{ 809 u_int refs; 810 811 refs = atomic_inc_int_nv(&r->r_refs); 812 KASSERT(refs != 0); 813 TRACEINDEX(refcnt, r->r_traceidx, r, refs - 1, +1); 814 (void)refs; 815} 816 817int 818refcnt_rele(struct refcnt *r) 819{ 820 u_int refs; 821 822 membar_exit_before_atomic(); 823 refs = atomic_dec_int_nv(&r->r_refs); 824 KASSERT(refs != ~0); 825 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 826 if (refs == 0) { 827 membar_enter_after_atomic(); 828 return (1); 829 } 830 return (0); 831} 832 833void 834refcnt_rele_wake(struct refcnt *r) 835{ 836 if (refcnt_rele(r)) 837 wakeup_one(r); 838} 839 840void 841refcnt_finalize(struct refcnt *r, const char *wmesg) 842{ 843 u_int refs; 844 845 membar_exit_before_atomic(); 846 refs = atomic_dec_int_nv(&r->r_refs); 847 KASSERT(refs != ~0); 848 TRACEINDEX(refcnt, r->r_traceidx, r, refs + 1, -1); 849 while (refs) { 850 sleep_setup(r, PWAIT, wmesg); 851 refs = atomic_load_int(&r->r_refs); 852 sleep_finish(0, refs); 853 } 854 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 855 /* Order subsequent loads and stores after refs == 0 load. */ 856 membar_sync(); 857} 858 859int 860refcnt_shared(struct refcnt *r) 861{ 862 u_int refs; 863 864 refs = atomic_load_int(&r->r_refs); 865 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 866 return (refs > 1); 867} 868 869unsigned int 870refcnt_read(struct refcnt *r) 871{ 872 u_int refs; 873 874 refs = atomic_load_int(&r->r_refs); 875 TRACEINDEX(refcnt, r->r_traceidx, r, refs, 0); 876 return (refs); 877} 878 879void 880cond_init(struct cond *c) 881{ 882 atomic_store_int(&c->c_wait, 1); 883} 884 885void 886cond_signal(struct cond *c) 887{ 888 atomic_store_int(&c->c_wait, 0); 889 890 wakeup_one(c); 891} 892 893void 894cond_wait(struct cond *c, const char *wmesg) 895{ 896 unsigned int wait; 897 898 wait = atomic_load_int(&c->c_wait); 899 while (wait) { 900 sleep_setup(c, PWAIT, wmesg); 901 wait = atomic_load_int(&c->c_wait); 902 sleep_finish(0, wait); 903 } 904} 905