52  * may _only_ be tuned in /etc/system or by patching the kernel binary; it
58  * timer_lock() locks the specified interval timer.  It doesn't look at the
59  * ITLK_REMOVE bit; it's up to callers to look at this if they need to
60  * care.  p_lock must be held on entry; it may be dropped and reaquired,
63  * Note that timer_create() doesn't call timer_lock(); it creates timers
67 timer_lock(proc_t *p, itimer_t *it)  in timer_lock()  argument
71 	while (it->it_lock & ITLK_LOCKED) {  in timer_lock()
72 		it->it_blockers++;  in timer_lock()
73 		cv_wait(&it->it_cv, &p->p_lock);  in timer_lock()
74 		it->it_blockers--;  in timer_lock()
77 	it->it_lock |= ITLK_LOCKED;  in timer_lock()
82  * waiters.  p_lock must be held on entry; it will not be dropped by
86 timer_unlock(proc_t *p, itimer_t *it)  in timer_unlock()  argument
89 	ASSERT(it->it_lock & ITLK_LOCKED);  in timer_unlock()
90 	it->it_lock &= ~ITLK_LOCKED;  in timer_unlock()
91 	cv_signal(&it->it_cv);  in timer_unlock()
96  * timer, and deletes the specified timer.  It must be called with p_lock
100  * blockers have seen the ITLK_REMOVE and cleared out.  It will then zero
107 timer_delete_locked(proc_t *p, timer_t tid, itimer_t *it)  in timer_delete_locked()  argument
110 	ASSERT(!(it->it_lock & ITLK_REMOVE));  in timer_delete_locked()
111 	ASSERT(it->it_lock & ITLK_LOCKED);  in timer_delete_locked()
113 	it->it_lock |= ITLK_REMOVE;  in timer_delete_locked()
121 	while (it->it_blockers) {  in timer_delete_locked()
122 		timer_unlock(p, it);  in timer_delete_locked()
123 		cv_wait(&it->it_cv, &p->p_lock);  in timer_delete_locked()
124 		timer_lock(p, it);  in timer_delete_locked()
128 	ASSERT(p->p_itimer[tid] == it);  in timer_delete_locked()
133 	 * p_itimer[tid] to be NULL; no one can find it).  Now we call into  in timer_delete_locked()
134 	 * the clock backend to delete the timer; it is up to the backend to  in timer_delete_locked()
140 	it->it_backend->clk_timer_delete(it);  in timer_delete_locked()
142 	if (it->it_portev) {  in timer_delete_locked()
143 		mutex_enter(&it->it_mutex);  in timer_delete_locked()
144 		if (it->it_portev) {  in timer_delete_locked()
147 			(void) port_dissociate_ksource(it->it_portfd,  in timer_delete_locked()
148 			    PORT_SOURCE_TIMER, (port_source_t *)it->it_portsrc);  in timer_delete_locked()
149 			pev = (port_kevent_t *)it->it_portev;  in timer_delete_locked()
150 			it->it_portev = NULL;  in timer_delete_locked()
151 			it->it_flags &= ~IT_PORT;  in timer_delete_locked()
152 			it->it_pending = 0;  in timer_delete_locked()
153 			mutex_exit(&it->it_mutex);  in timer_delete_locked()
157 			mutex_exit(&it->it_mutex);  in timer_delete_locked()
169 	if (it->it_pending > 0) {  in timer_delete_locked()
170 		it->it_sigq->sq_func = NULL;  in timer_delete_locked()
172 		kmem_free(it->it_sigq, sizeof (sigqueue_t));  in timer_delete_locked()
175 	ASSERT(it->it_blockers == 0);  in timer_delete_locked()
176 	kmem_cache_free(clock_timer_cache, it);  in timer_delete_locked()
190  * If timer_grab() fails, it will return NULL.  timer_grab() will fail if
204 	itimer_t **itp, *it;  in timer_grab()  local
213 	    (it = itp[tid]) == NULL) {  in timer_grab()
218 	timer_lock(p, it);  in timer_grab()
220 	if (it->it_lock & ITLK_REMOVE) {  in timer_grab()
222 		 * Someone is removing this timer; it will soon be invalid.  in timer_grab()
224 		timer_unlock(p, it);  in timer_grab()
231 	return (it);  in timer_grab()
237  * will drop it before returning.
240 timer_release(proc_t *p, itimer_t *it)  in timer_release()  argument
243 	timer_unlock(p, it);  in timer_release()
250  * p_lock, but will drop it before returning.
253 timer_delete_grabbed(proc_t *p, timer_t tid, itimer_t *it)  in timer_delete_grabbed()  argument
256 	timer_delete_locked(p, tid, it);  in timer_delete_grabbed()
403 	itimer_t *it = (itimer_t *)sigq->sq_backptr;  in timer_signal()  local
411 	mutex_enter(&it->it_mutex);  in timer_signal()
412 	ASSERT(it->it_pending > 0);  in timer_signal()
413 	it->it_overrun = it->it_pending - 1;  in timer_signal()
414 	it->it_pending = 0;  in timer_signal()
415 	mutex_exit(&it->it_mutex);  in timer_signal()
422 timer_fire(itimer_t *it)  in timer_fire()  argument
427 	if (it->it_flags & IT_SIGNAL) {  in timer_fire()
429 		 * See the comment in timer_signal() for why it is not  in timer_fire()
435 		p = it->it_proc;  in timer_fire()
446 		 * We don't need to use the p_lock because it is only  in timer_fire()
456 	mutex_enter(&it->it_mutex);  in timer_fire()
458 	if (it->it_pending > 0) {  in timer_fire()
459 		if (it->it_pending < INT_MAX)  in timer_fire()
460 			it->it_pending++;  in timer_fire()
461 		mutex_exit(&it->it_mutex);  in timer_fire()
463 		if (it->it_flags & IT_PORT) {  in timer_fire()
464 			it->it_pending = 1;  in timer_fire()
465 			port_send_event((port_kevent_t *)it->it_portev);  in timer_fire()
466 			mutex_exit(&it->it_mutex);  in timer_fire()
467 		} else if (it->it_flags & IT_SIGNAL) {  in timer_fire()
468 			it->it_pending = 1;  in timer_fire()
469 			mutex_exit(&it->it_mutex);  in timer_fire()
470 			sigaddqa(p, NULL, it->it_sigq);  in timer_fire()
472 			mutex_exit(&it->it_mutex);  in timer_fire()
513 			 * Since we just allocated it, we know slot 0 is  in timer_get_id()
566 	 * It's possible that other lower-indexed timers were freed while  in timer_get_id()
589 	itimer_t *it;  in timer_create()  local
665 	 * If we can't find an empty slot, we'll free it before returning.  in timer_create()
670 	 * Allocate a timer and choose a slot for it.  in timer_create()
672 	it = kmem_cache_alloc(clock_timer_cache, KM_SLEEP);  in timer_create()
673 	bzero(it, sizeof (*it));  in timer_create()
674 	mutex_init(&it->it_mutex, NULL, MUTEX_DEFAULT, NULL);  in timer_create()
679 		kmem_cache_free(clock_timer_cache, it);  in timer_create()
702 	sigq->sq_backptr = it;  in timer_create()
703 	it->it_sigq = sigq;  in timer_create()
704 	it->it_backend = backend;  in timer_create()
705 	it->it_lock = ITLK_LOCKED;  in timer_create()
714 		 * - allocate a port event structure and prepare it to be sent  in timer_create()
728 		it->it_flags |= IT_PORT;  in timer_create()
733 		    (port_source_t **)&it->it_portsrc, timer_close_port,  in timer_create()
734 		    (void *)it, NULL);  in timer_create()
737 			kmem_cache_free(clock_timer_cache, it);  in timer_create()
747 			    (port_source_t *)it->it_portsrc);  in timer_create()
749 			kmem_cache_free(clock_timer_cache, it);  in timer_create()
756 		    timer_port_callback, it);  in timer_create()
757 		it->it_portev = pkevp;  in timer_create()
758 		it->it_portfd = port;  in timer_create()
761 			it->it_flags |= IT_SIGNAL;  in timer_create()
765 	p->p_itimer[i] = it;  in timer_create()
772 	if ((error = backend->clk_timer_create(it, timer_fire)) != 0)  in timer_create()
775 	it->it_lwp = ttolwp(curthread);  in timer_create()
776 	it->it_proc = p;  in timer_create()
787 	timer_release(p, it);  in timer_create()
795 	 * Since we never unlocked the timer (it was born locked), it's  in timer_create()
798 	ASSERT(!(it->it_lock & ITLK_REMOVE));  in timer_create()
799 	timer_delete_grabbed(p, i, it);  in timer_create()
808 	itimer_t *it;  in timer_gettime()  local
812 	if ((it = timer_grab(p, tid)) == NULL)  in timer_gettime()
815 	error = it->it_backend->clk_timer_gettime(it, &when);  in timer_gettime()
817 	timer_release(p, it);  in timer_gettime()
843 	itimer_t *it;  in timer_settime()  local
870 	if ((it = timer_grab(p, tid)) == NULL)  in timer_settime()
873 	error = it->it_backend->clk_timer_settime(it, flags, &when);  in timer_settime()
875 	timer_release(p, it);  in timer_settime()
884 	itimer_t *it;  in timer_delete()  local
886 	if ((it = timer_grab(p, tid)) == NULL)  in timer_delete()
889 	timer_delete_grabbed(p, tid, it);  in timer_delete()
899 	itimer_t *it;  in timer_getoverrun()  local
901 	if ((it = timer_grab(p, tid)) == NULL)  in timer_getoverrun()
906 	 * it before looking at the value.  in timer_getoverrun()
909 	overrun = it->it_overrun;  in timer_getoverrun()
912 	timer_release(p, it);  in timer_getoverrun()
926 	itimer_t *it, **itp;  in timer_lwpexit()  local
934 		if ((it = itp[i]) == NULL)  in timer_lwpexit()
937 		timer_lock(p, it);  in timer_lwpexit()
939 		if ((it->it_lock & ITLK_REMOVE) || it->it_lwp != lwp) {  in timer_lwpexit()
941 			 * This timer is either being removed or it isn't  in timer_lwpexit()
944 			timer_unlock(p, it);  in timer_lwpexit()
955 		it->it_lwp = NULL;  in timer_lwpexit()
956 		timer_unlock(p, it);  in timer_lwpexit()
970 	itimer_t *it, **itp;  in timer_lwpbind()  local
978 		if ((it = itp[i]) == NULL)  in timer_lwpbind()
981 		timer_lock(p, it);  in timer_lwpbind()
983 		if (!(it->it_lock & ITLK_REMOVE) && it->it_lwp == lwp) {  in timer_lwpbind()
988 			it->it_backend->clk_timer_lwpbind(it);  in timer_lwpbind()
992 		timer_unlock(p, it);  in timer_lwpbind()
1028 	itimer_t	*it = arg;  in timer_port_callback()  local
1030 	mutex_enter(&it->it_mutex);  in timer_port_callback()
1031 	if (curproc != it->it_proc) {  in timer_port_callback()
1033 		mutex_exit(&it->it_mutex);  in timer_port_callback()
1036 	*events = it->it_pending;	/* 1 = 1 event, >1 # of overflows */  in timer_port_callback()
1037 	it->it_pending = 0;		/* reinit overflow counter	*/  in timer_port_callback()
1048 	mutex_exit(&it->it_mutex);  in timer_port_callback()
1055  * the port and it is not useable in this case.
1066 	itimer_t	*it;  in timer_close_port()  local
1069 		if ((it = timer_grab(p, tid)) == NULL)  in timer_close_port()
1071 		if (it->it_portev) {  in timer_close_port()
1072 			mutex_enter(&it->it_mutex);  in timer_close_port()
1073 			if (it->it_portfd == port) {  in timer_close_port()
1075 				pev = (port_kevent_t *)it->it_portev;  in timer_close_port()
1076 				it->it_portev = NULL;  in timer_close_port()
1077 				it->it_flags &= ~IT_PORT;  in timer_close_port()
1078 				mutex_exit(&it->it_mutex);  in timer_close_port()
1082 				mutex_exit(&it->it_mutex);  in timer_close_port()
1085 		timer_release(p, it);  in timer_close_port()