2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <atomic_ops.h>
33 #include "thr_private.h"
35 #define SPIN_COUNT 10000
37 __weak_reference(_pthread_spin_init, pthread_spin_init);
38 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
39 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
40 __weak_reference(_pthread_spin_lock, pthread_spin_lock);
41 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
44 _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
46 struct pthread_spinlock *lck;
49 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
51 else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
64 _pthread_spin_destroy(pthread_spinlock_t *lock)
68 if (lock == NULL || *lock == NULL)
70 else if ((*lock)->s_owner != NULL)
82 _pthread_spin_trylock(pthread_spinlock_t *lock)
84 struct pthread_spinlock *lck;
85 struct pthread *self = _pthread_self();
88 if (lock == NULL || (lck = *lock) == NULL)
90 else if (lck->s_owner == self)
92 else if (lck->s_lock != 0)
95 atomic_swap_int((int *)&(lck)->s_lock, 1, &oldval);
99 lck->s_owner = _pthread_self();
107 _pthread_spin_lock(pthread_spinlock_t *lock)
109 struct pthread_spinlock *lck;
110 struct pthread *self = _pthread_self();
111 int count, oldval, ret;
113 if (lock == NULL || (lck = *lock) == NULL)
115 else if (lck->s_owner == self)
120 while (lck->s_lock) {
122 /* tell cpu we are spinning */
123 __asm __volatile("pause");
130 atomic_swap_int((int *)&(lck)->s_lock, 1, &oldval);
141 _pthread_spin_unlock(pthread_spinlock_t *lock)
143 struct pthread_spinlock *lck;
146 if (lock == NULL || (lck = *lock) == NULL)
149 if (lck->s_owner != _pthread_self())
153 atomic_swap_int((int *)&lck->s_lock, 0, &ret);