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 "namespace.h" 30#include <sys/types.h> 31#include <errno.h> 32#include <pthread.h> 33#include <stdint.h> 34#include <stdlib.h> 35#include "un-namespace.h" 36 37#include "atomic_ops.h" 38#include "thr_private.h" 39 40#define SPIN_COUNT 10000 41 42__weak_reference(_pthread_spin_init, pthread_spin_init); 43__weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 44__weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 45__weak_reference(_pthread_spin_lock, pthread_spin_lock); 46__weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 47 48int 49_pthread_spin_init(pthread_spinlock_t *lock, int pshared) 50{ 51 struct pthread_spinlock *lck; 52 int ret; 53 54 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE) 55 ret = EINVAL; 56 else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL) 57 ret = ENOMEM; 58 else { 59 lck->s_lock = 0; 60 lck->s_owner= NULL; 61 *lock = lck; 62 ret = 0; 63 } 64 65 return (ret); 66} 67 68int 69_pthread_spin_destroy(pthread_spinlock_t *lock) 70{ 71 int ret; 72 73 if (lock == NULL || *lock == NULL) 74 ret = EINVAL; 75 else if ((*lock)->s_owner != NULL) 76 ret = EBUSY; 77 else { 78 free(*lock); 79 *lock = NULL; 80 ret = 0; 81 } 82 83 return (ret); 84} 85 86int 87_pthread_spin_trylock(pthread_spinlock_t *lock) 88{ 89 struct pthread_spinlock *lck; 90 struct pthread *self = _pthread_self(); 91 int oldval, ret; 92 93 if (lock == NULL || (lck = *lock) == NULL) 94 ret = EINVAL; 95 else if (lck->s_owner == self) 96 ret = EDEADLK; 97 else if (lck->s_lock != 0) 98 ret = EBUSY; 99 else { 100 atomic_swap_int(&(lck)->s_lock, 1, &oldval); 101 if (oldval) 102 ret = EBUSY; 103 else { 104 lck->s_owner = _pthread_self(); 105 ret = 0; 106 } 107 } 108 return (ret); 109} 110 111int 112_pthread_spin_lock(pthread_spinlock_t *lock) 113{ 114 struct pthread_spinlock *lck; 115 struct pthread *self = _pthread_self(); 116 int count, oldval, ret; 117 118 if (lock == NULL || (lck = *lock) == NULL) 119 ret = EINVAL; 120 else if (lck->s_owner == self) 121 ret = EDEADLK; 122 else { 123 do { 124 count = SPIN_COUNT; 125 while (lck->s_lock) { 126#ifdef __i386__ 127 /* tell cpu we are spinning */ 128 __asm __volatile("pause"); 129#endif 130 if (--count <= 0) { 131 count = SPIN_COUNT; 132 _pthread_yield(); 133 } 134 } 135 atomic_swap_int(&(lck)->s_lock, 1, &oldval); 136 } while (oldval); 137 138 lck->s_owner = self; 139 ret = 0; 140 } 141 142 return (ret); 143} 144 145int 146_pthread_spin_unlock(pthread_spinlock_t *lock) 147{ 148 struct pthread_spinlock *lck; 149 int ret; 150 151 if (lock == NULL || (lck = *lock) == NULL) 152 ret = EINVAL; 153 else { 154 if (lck->s_owner != _pthread_self()) 155 ret = EPERM; 156 else { 157 lck->s_owner = NULL; 158 atomic_swap_int(&lck->s_lock, 0, &ret); 159 ret = 0; 160 } 161 } 162 163 return (ret); 164} 165 166