1 /*- 2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 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. 13 * 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 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <errno.h> 30 #include <stdlib.h> 31 #include <pthread.h> 32 #include "thr_private.h" 33 34 #define SPIN_COUNT 100000 35 36 __weak_reference(_pthread_spin_init, pthread_spin_init); 37 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 38 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 39 __weak_reference(_pthread_spin_lock, pthread_spin_lock); 40 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 41 42 int 43 _pthread_spin_init(pthread_spinlock_t *lock, int pshared) 44 { 45 struct pthread_spinlock *lck; 46 int ret; 47 48 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE) 49 ret = EINVAL; 50 else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL) 51 ret = ENOMEM; 52 else { 53 _thr_umtx_init(&lck->s_lock); 54 *lock = lck; 55 ret = 0; 56 } 57 58 return (ret); 59 } 60 61 int 62 _pthread_spin_destroy(pthread_spinlock_t *lock) 63 { 64 int ret; 65 66 if (lock == NULL || *lock == NULL) 67 ret = EINVAL; 68 else { 69 free(*lock); 70 *lock = NULL; 71 ret = 0; 72 } 73 74 return (ret); 75 } 76 77 int 78 _pthread_spin_trylock(pthread_spinlock_t *lock) 79 { 80 struct pthread *curthread = _get_curthread(); 81 struct pthread_spinlock *lck; 82 int ret; 83 84 if (lock == NULL || (lck = *lock) == NULL) 85 ret = EINVAL; 86 else 87 ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock); 88 return (ret); 89 } 90 91 int 92 _pthread_spin_lock(pthread_spinlock_t *lock) 93 { 94 struct pthread *curthread = _get_curthread(); 95 struct pthread_spinlock *lck; 96 int ret, count; 97 98 if (lock == NULL || (lck = *lock) == NULL) 99 ret = EINVAL; 100 else { 101 count = SPIN_COUNT; 102 while ((ret = THR_UMTX_TRYLOCK(curthread, &lck->s_lock)) != 0) { 103 while (lck->s_lock) { 104 #ifdef __i386__ 105 /* tell cpu we are spinning */ 106 __asm __volatile("pause"); 107 #endif 108 if (--count <= 0) { 109 count = SPIN_COUNT; 110 _pthread_yield(); 111 } 112 } 113 } 114 ret = 0; 115 } 116 117 return (ret); 118 } 119 120 int 121 _pthread_spin_unlock(pthread_spinlock_t *lock) 122 { 123 struct pthread *curthread = _get_curthread(); 124 struct pthread_spinlock *lck; 125 int ret; 126 127 if (lock == NULL || (lck = *lock) == NULL) 128 ret = EINVAL; 129 else { 130 ret = THR_UMTX_UNLOCK(curthread, &lck->s_lock); 131 } 132 return (ret); 133 } 134