xref: /freebsd-9.3-release/lib/libthr/thread/thr_umtx.c

/*
 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
 * All rights reserved.
 *
 * 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 unmodified, 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * $FreeBSD$
 *
 */

#include "thr_private.h"
#include "thr_umtx.h"

#ifndef HAS__UMTX_OP_ERR
int _umtx_op_err(void *obj, int op, u_long val, void *uaddr, void *uaddr2)
{
	if (_umtx_op(obj, op, val, uaddr, uaddr2) == -1)
		return (errno);
	return (0);
}
#endif

void
_thr_umutex_init(struct umutex *mtx)
{
	static struct umutex default_mtx = DEFAULT_UMUTEX;

	*mtx = default_mtx;
}

void
_thr_urwlock_init(struct urwlock *rwl)
{
	static struct urwlock default_rwl = DEFAULT_URWLOCK;
	*rwl = default_rwl;
}

int
__thr_umutex_lock(struct umutex *mtx, uint32_t id)
{
	uint32_t owner;

	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
		for (;;) {
			/* wait in kernel */
			_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);

			owner = mtx->m_owner;
			if ((owner & ~UMUTEX_CONTESTED) == 0 &&
			     atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
				return (0);
		}
	}

	return	_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
}

#define SPINLOOPS 1000

int
__thr_umutex_lock_spin(struct umutex *mtx, uint32_t id)
{
	uint32_t owner;

	if (!_thr_is_smp)
		return __thr_umutex_lock(mtx, id);

	if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
		for (;;) {
			int count = SPINLOOPS;
			while (count--) {
				owner = mtx->m_owner;
				if ((owner & ~UMUTEX_CONTESTED) == 0) {
					if (atomic_cmpset_acq_32(
					    &mtx->m_owner,
					    owner, id|owner)) {
						return (0);
					}
				}
				CPU_SPINWAIT;
			}

			/* wait in kernel */
			_umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, 0);
		}
	}

	return	_umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, 0);
}

int
__thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
	const struct timespec *ets)
{
	struct timespec timo, cts;
	uint32_t owner;
	int ret;

	clock_gettime(CLOCK_REALTIME, &cts);
	TIMESPEC_SUB(&timo, ets, &cts);

	if (timo.tv_sec < 0)
		return (ETIMEDOUT);

	for (;;) {
		if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {

			/* wait in kernel */
			ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_WAIT, 0, 0, &timo);

			/* now try to lock it */
			owner = mtx->m_owner;
			if ((owner & ~UMUTEX_CONTESTED) == 0 &&
			     atomic_cmpset_acq_32(&mtx->m_owner, owner, id|owner))
				return (0);
		} else {
			ret = _umtx_op_err(mtx, UMTX_OP_MUTEX_LOCK, 0, 0, &timo);
			if (ret == 0)
				break;
		}
		if (ret == ETIMEDOUT)
			break;
		clock_gettime(CLOCK_REALTIME, &cts);
		TIMESPEC_SUB(&timo, ets, &cts);
		if (timo.tv_sec < 0 || (timo.tv_sec == 0 && timo.tv_nsec == 0)) {
			ret = ETIMEDOUT;
			break;
		}
	}
	return (ret);
}

int
__thr_umutex_unlock(struct umutex *mtx, uint32_t id)
{
	static int wake2_avail = 0;

	if (__predict_false(wake2_avail == 0)) {
		struct umutex test = DEFAULT_UMUTEX;

		if (_umtx_op(&test, UMTX_OP_MUTEX_WAKE2, test.m_flags, 0, 0) == -1)
			wake2_avail = -1;
		else
			wake2_avail = 1;
	}

	if (wake2_avail != 1)
		goto unlock;

	uint32_t flags = mtx->m_flags;

	if ((flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) {
		uint32_t owner;
		do {
			owner = mtx->m_owner;
			if (__predict_false((owner & ~UMUTEX_CONTESTED) != id))
				return (EPERM);
		} while (__predict_false(!atomic_cmpset_rel_32(&mtx->m_owner,
					 owner, UMUTEX_UNOWNED)));
		if ((owner & UMUTEX_CONTESTED))
			(void)_umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE2, flags, 0, 0);
		return (0);
	}
unlock:
	return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0);
}

int
__thr_umutex_trylock(struct umutex *mtx)
{
	return _umtx_op_err(mtx, UMTX_OP_MUTEX_TRYLOCK, 0, 0, 0);
}

int
__thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
	uint32_t *oldceiling)
{
	return _umtx_op_err(mtx, UMTX_OP_SET_CEILING, ceiling, oldceiling, 0);
}

int
_thr_umtx_wait(volatile long *mtx, long id, const struct timespec *timeout)
{
	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
		timeout->tv_nsec <= 0)))
		return (ETIMEDOUT);
	return _umtx_op_err(__DEVOLATILE(void *, mtx), UMTX_OP_WAIT, id, 0,
		__DECONST(void*, timeout));
}

int
_thr_umtx_wait_uint(volatile u_int *mtx, u_int id, const struct timespec *timeout, int shared)
{
	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
		timeout->tv_nsec <= 0)))
		return (ETIMEDOUT);
	return _umtx_op_err(__DEVOLATILE(void *, mtx),
			shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, 0,
			__DECONST(void*, timeout));
}

int
_thr_umtx_timedwait_uint(volatile u_int *mtx, u_int id, int clockid,
	const struct timespec *abstime, int shared)
{
	struct timespec ts, ts2, *tsp;

	if (abstime != NULL) {
		clock_gettime(clockid, &ts);
		TIMESPEC_SUB(&ts2, abstime, &ts);
		if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0))
			return (ETIMEDOUT);
		tsp = &ts2;
	} else {
		tsp = NULL;
	}
	return _umtx_op_err(__DEVOLATILE(void *, mtx),
		shared ? UMTX_OP_WAIT_UINT : UMTX_OP_WAIT_UINT_PRIVATE, id, NULL,
			tsp);
}

int
_thr_umtx_wake(volatile void *mtx, int nr_wakeup, int shared)
{
	return _umtx_op_err(__DEVOLATILE(void *, mtx), shared ? UMTX_OP_WAKE : UMTX_OP_WAKE_PRIVATE,
		nr_wakeup, 0, 0);
}

void
_thr_ucond_init(struct ucond *cv)
{
	bzero(cv, sizeof(struct ucond));
}

int
_thr_ucond_wait(struct ucond *cv, struct umutex *m,
	const struct timespec *timeout, int flags)
{
	if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
	    timeout->tv_nsec <= 0))) {
		struct pthread *curthread = _get_curthread();
		_thr_umutex_unlock(m, TID(curthread));
                return (ETIMEDOUT);
	}
	return _umtx_op_err(cv, UMTX_OP_CV_WAIT, flags,
		     m, __DECONST(void*, timeout));
}

int
_thr_ucond_signal(struct ucond *cv)
{
	if (!cv->c_has_waiters)
		return (0);
	return _umtx_op_err(cv, UMTX_OP_CV_SIGNAL, 0, NULL, NULL);
}

int
_thr_ucond_broadcast(struct ucond *cv)
{
	if (!cv->c_has_waiters)
		return (0);
	return _umtx_op_err(cv, UMTX_OP_CV_BROADCAST, 0, NULL, NULL);
}

int
__thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp)
{
	return _umtx_op_err(rwlock, UMTX_OP_RW_RDLOCK, flags, NULL, tsp);
}

int
__thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp)
{
	return _umtx_op_err(rwlock, UMTX_OP_RW_WRLOCK, 0, NULL, tsp);
}

int
__thr_rwlock_unlock(struct urwlock *rwlock)
{
	return _umtx_op_err(rwlock, UMTX_OP_RW_UNLOCK, 0, NULL, NULL);
}

void
_thr_rwl_rdlock(struct urwlock *rwlock)
{
	int ret;

	for (;;) {
		if (_thr_rwlock_tryrdlock(rwlock, URWLOCK_PREFER_READER) == 0)
			return;
		ret = __thr_rwlock_rdlock(rwlock, URWLOCK_PREFER_READER, NULL);
		if (ret == 0)
			return;
		if (ret != EINTR)
			PANIC("rdlock error");
	}
}

void
_thr_rwl_wrlock(struct urwlock *rwlock)
{
	int ret;

	for (;;) {
		if (_thr_rwlock_trywrlock(rwlock) == 0)
			return;
		ret = __thr_rwlock_wrlock(rwlock, NULL);
		if (ret == 0)
			return;
		if (ret != EINTR)
			PANIC("wrlock error");
	}
}

void
_thr_rwl_unlock(struct urwlock *rwlock)
{
	if (_thr_rwlock_unlock(rwlock))
		PANIC("unlock error");
}