/* $OpenBSD: kern_synch.c,v 1.104 2012/08/21 19:51:58 haesbaert Exp $ */ /* $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1990, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_synch.c 8.6 (Berkeley) 1/21/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #endif /* * We're only looking at 7 bits of the address; everything is * aligned to 4, lots of things are aligned to greater powers * of 2. Shift right by 8, i.e. drop the bottom 256 worth. */ #define TABLESIZE 128 #define LOOKUP(x) (((long)(x) >> 8) & (TABLESIZE - 1)) TAILQ_HEAD(slpque,proc) slpque[TABLESIZE]; void sleep_queue_init(void) { int i; for (i = 0; i < TABLESIZE; i++) TAILQ_INIT(&slpque[i]); } /* * During autoconfiguration or after a panic, a sleep will simply * lower the priority briefly to allow interrupts, then return. * The priority to be used (safepri) is machine-dependent, thus this * value is initialized and maintained in the machine-dependent layers. * This priority will typically be 0, or the lowest priority * that is safe for use on the interrupt stack; it can be made * higher to block network software interrupts after panics. */ extern int safepri; /* * General sleep call. Suspends the current process until a wakeup is * performed on the specified identifier. The process will then be made * runnable with the specified priority. Sleeps at most timo/hz seconds * (0 means no timeout). If pri includes PCATCH flag, signals are checked * before and after sleeping, else signals are not checked. Returns 0 if * awakened, EWOULDBLOCK if the timeout expires. If PCATCH is set and a * signal needs to be delivered, ERESTART is returned if the current system * call should be restarted if possible, and EINTR is returned if the system * call should be interrupted by the signal (return EINTR). */ int tsleep(const volatile void *ident, int priority, const char *wmesg, int timo) { struct sleep_state sls; int error, error1; if (cold || panicstr) { int s; /* * After a panic, or during autoconfiguration, * just give interrupts a chance, then just return; * don't run any other procs or panic below, * in case this is the idle process and already asleep. */ s = splhigh(); splx(safepri); splx(s); return (0); } sleep_setup(&sls, ident, priority, wmesg); sleep_setup_timeout(&sls, timo); sleep_setup_signal(&sls, priority); sleep_finish(&sls, 1); error1 = sleep_finish_timeout(&sls); error = sleep_finish_signal(&sls); /* Signal errors are higher priority than timeouts. */ if (error == 0 && error1 != 0) error = error1; return (error); } /* * Same as tsleep, but if we have a mutex provided, then once we've * entered the sleep queue we drop the mutex. After sleeping we re-lock. */ int msleep(const volatile void *ident, struct mutex *mtx, int priority, const char *wmesg, int timo) { struct sleep_state sls; int error, error1, spl; sleep_setup(&sls, ident, priority, wmesg); sleep_setup_timeout(&sls, timo); sleep_setup_signal(&sls, priority); if (mtx) { /* XXX - We need to make sure that the mutex doesn't * unblock splsched. This can be made a bit more * correct when the sched_lock is a mutex. */ spl = MUTEX_OLDIPL(mtx); MUTEX_OLDIPL(mtx) = splsched(); mtx_leave(mtx); } sleep_finish(&sls, 1); error1 = sleep_finish_timeout(&sls); error = sleep_finish_signal(&sls); if (mtx) { if ((priority & PNORELOCK) == 0) { mtx_enter(mtx); MUTEX_OLDIPL(mtx) = spl; /* put the ipl back */ } else splx(spl); } /* Signal errors are higher priority than timeouts. */ if (error == 0 && error1 != 0) error = error1; return (error); } void sleep_setup(struct sleep_state *sls, const volatile void *ident, int prio, const char *wmesg) { struct proc *p = curproc; #ifdef DIAGNOSTIC if (ident == NULL) panic("tsleep: no ident"); if (p->p_stat != SONPROC) panic("tsleep: not SONPROC"); #endif #ifdef KTRACE if (KTRPOINT(p, KTR_CSW)) ktrcsw(p, 1, 0); #endif sls->sls_catch = 0; sls->sls_do_sleep = 1; sls->sls_sig = 1; SCHED_LOCK(sls->sls_s); p->p_wchan = ident; p->p_wmesg = wmesg; p->p_slptime = 0; p->p_priority = prio & PRIMASK; TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_runq); } void sleep_finish(struct sleep_state *sls, int do_sleep) { struct proc *p = curproc; if (sls->sls_do_sleep && do_sleep) { p->p_stat = SSLEEP; p->p_ru.ru_nvcsw++; SCHED_ASSERT_LOCKED(); mi_switch(); } else if (!do_sleep) { unsleep(p); } #ifdef DIAGNOSTIC if (p->p_stat != SONPROC) panic("sleep_finish !SONPROC"); #endif p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; SCHED_UNLOCK(sls->sls_s); /* * Even though this belongs to the signal handling part of sleep, * we need to clear it before the ktrace. */ atomic_clearbits_int(&p->p_flag, P_SINTR); #ifdef KTRACE if (KTRPOINT(p, KTR_CSW)) ktrcsw(p, 0, 0); #endif } void sleep_setup_timeout(struct sleep_state *sls, int timo) { if (timo) timeout_add(&curproc->p_sleep_to, timo); } int sleep_finish_timeout(struct sleep_state *sls) { struct proc *p = curproc; if (p->p_flag & P_TIMEOUT) { atomic_clearbits_int(&p->p_flag, P_TIMEOUT); return (EWOULDBLOCK); } else if (timeout_pending(&p->p_sleep_to)) { timeout_del(&p->p_sleep_to); } return (0); } void sleep_setup_signal(struct sleep_state *sls, int prio) { struct proc *p = curproc; if ((sls->sls_catch = (prio & PCATCH)) == 0) return; /* * We put ourselves on the sleep queue and start our timeout * before calling CURSIG, as we could stop there, and a wakeup * or a SIGCONT (or both) could occur while we were stopped. * A SIGCONT would cause us to be marked as SSLEEP * without resuming us, thus we must be ready for sleep * when CURSIG is called. If the wakeup happens while we're * stopped, p->p_wchan will be 0 upon return from CURSIG. */ atomic_setbits_int(&p->p_flag, P_SINTR); if (p->p_p->ps_single != NULL || (sls->sls_sig = CURSIG(p)) != 0) { if (p->p_wchan) unsleep(p); p->p_stat = SONPROC; sls->sls_do_sleep = 0; } else if (p->p_wchan == 0) { sls->sls_catch = 0; sls->sls_do_sleep = 0; } } int sleep_finish_signal(struct sleep_state *sls) { struct proc *p = curproc; int error; if (sls->sls_catch != 0) { if ((error = single_thread_check(p, 1))) return (error); if (sls->sls_sig != 0 || (sls->sls_sig = CURSIG(p)) != 0) { if (p->p_sigacts->ps_sigintr & sigmask(sls->sls_sig)) return (EINTR); return (ERESTART); } } return (0); } /* * Implement timeout for tsleep. * If process hasn't been awakened (wchan non-zero), * set timeout flag and undo the sleep. If proc * is stopped, just unsleep so it will remain stopped. */ void endtsleep(void *arg) { struct proc *p = arg; int s; SCHED_LOCK(s); if (p->p_wchan) { if (p->p_stat == SSLEEP) setrunnable(p); else unsleep(p); atomic_setbits_int(&p->p_flag, P_TIMEOUT); } SCHED_UNLOCK(s); } /* * Remove a process from its wait queue */ void unsleep(struct proc *p) { if (p->p_wchan) { TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq); p->p_wchan = NULL; } } /* * Make a number of processes sleeping on the specified identifier runnable. */ void wakeup_n(const volatile void *ident, int n) { struct slpque *qp; struct proc *p; struct proc *pnext; int s; SCHED_LOCK(s); qp = &slpque[LOOKUP(ident)]; for (p = TAILQ_FIRST(qp); p != NULL && n != 0; p = pnext) { pnext = TAILQ_NEXT(p, p_runq); #ifdef DIAGNOSTIC if (p->p_stat != SSLEEP && p->p_stat != SSTOP) panic("wakeup: p_stat is %d", (int)p->p_stat); #endif if (p->p_wchan == ident) { --n; p->p_wchan = 0; TAILQ_REMOVE(qp, p, p_runq); if (p->p_stat == SSLEEP) setrunnable(p); } } SCHED_UNLOCK(s); } /* * Make all processes sleeping on the specified identifier runnable. */ void wakeup(const volatile void *chan) { wakeup_n(chan, -1); } int sys_sched_yield(struct proc *p, void *v, register_t *retval) { yield(); return (0); } int sys___thrsleep(struct proc *p, void *v, register_t *retval) { struct sys___thrsleep_args /* { syscallarg(const volatile void *) ident; syscallarg(clockid_t) clock_id; syscallarg(struct timespec *) tp; syscallarg(void *) lock; syscallarg(const int *) abort; } */ *uap = v; long ident = (long)SCARG(uap, ident); _spinlock_lock_t *lock = SCARG(uap, lock); static _spinlock_lock_t unlocked = _SPINLOCK_UNLOCKED; long long to_ticks = 0; int abort, error; if (!rthreads_enabled) { *retval = ENOTSUP; return (0); } if (ident == 0) { *retval = EINVAL; return (0); } if (SCARG(uap, tp) != NULL) { struct timespec now, ats; if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) || (error = clock_gettime(p, SCARG(uap, clock_id), &now))) { *retval = error; return (0); } #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrabstimespec(p, &ats); #endif if (timespeccmp(&ats, &now, <)) { /* already passed: still do the unlock */ if (lock) { if ((error = copyout(&unlocked, lock, sizeof(unlocked))) != 0) { *retval = error; return (0); } } *retval = EWOULDBLOCK; return (0); } timespecsub(&ats, &now, &ats); to_ticks = (long long)hz * ats.tv_sec + (ats.tv_nsec + tick * 1000 - 1) / (tick * 1000) + 1; if (to_ticks > INT_MAX) to_ticks = INT_MAX; } p->p_thrslpid = ident; if (lock) { if ((error = copyout(&unlocked, lock, sizeof(unlocked))) != 0) goto out; } if (SCARG(uap, abort) != NULL) { if ((error = copyin(SCARG(uap, abort), &abort, sizeof(abort))) != 0) goto out; if (abort) { error = EINTR; goto out; } } if (p->p_thrslpid == 0) error = 0; else error = tsleep(&p->p_thrslpid, PUSER | PCATCH, "thrsleep", (int)to_ticks); out: p->p_thrslpid = 0; if (error == ERESTART) error = EINTR; *retval = error; return (0); } int sys___thrwakeup(struct proc *p, void *v, register_t *retval) { struct sys___thrwakeup_args /* { syscallarg(const volatile void *) ident; syscallarg(int) n; } */ *uap = v; long ident = (long)SCARG(uap, ident); int n = SCARG(uap, n); struct proc *q; int found = 0; if (!rthreads_enabled) *retval = ENOTSUP; else if (ident == 0) *retval = EINVAL; else { TAILQ_FOREACH(q, &p->p_p->ps_threads, p_thr_link) { if (q->p_thrslpid == ident) { wakeup_one(&q->p_thrslpid); q->p_thrslpid = 0; if (++found == n) break; } } *retval = found ? 0 : ESRCH; } return (0); }