1 /*- 2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 3 * Copyright (c) 2016 The FreeBSD Foundation 4 * All rights reserved. 5 * 6 * Portions of this software were developed by Konstantin Belousov 7 * under sponsorship from the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD$ 31 */ 32 33 #include "namespace.h" 34 #include <errno.h> 35 #include <stdlib.h> 36 #include <pthread.h> 37 #include "un-namespace.h" 38 39 #include "thr_private.h" 40 41 #define SPIN_COUNT 100000 42 43 __weak_reference(_pthread_spin_init, pthread_spin_init); 44 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 45 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 46 __weak_reference(_pthread_spin_lock, pthread_spin_lock); 47 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 48 49 int 50 _pthread_spin_init(pthread_spinlock_t *lock, int pshared) 51 { 52 struct pthread_spinlock *lck; 53 54 if (lock == NULL) 55 return (EINVAL); 56 if (pshared == PTHREAD_PROCESS_PRIVATE) { 57 lck = malloc(sizeof(struct pthread_spinlock)); 58 if (lck == NULL) 59 return (ENOMEM); 60 *lock = lck; 61 } else if (pshared == PTHREAD_PROCESS_SHARED) { 62 lck = __thr_pshared_offpage(lock, 1); 63 if (lck == NULL) 64 return (EFAULT); 65 *lock = THR_PSHARED_PTR; 66 } else { 67 return (EINVAL); 68 } 69 _thr_umutex_init(&lck->s_lock); 70 return (0); 71 } 72 73 int 74 _pthread_spin_destroy(pthread_spinlock_t *lock) 75 { 76 void *l; 77 int ret; 78 79 if (lock == NULL || *lock == NULL) { 80 ret = EINVAL; 81 } else if (*lock == THR_PSHARED_PTR) { 82 l = __thr_pshared_offpage(lock, 0); 83 if (l != NULL) 84 __thr_pshared_destroy(l); 85 ret = 0; 86 } else { 87 free(*lock); 88 *lock = NULL; 89 ret = 0; 90 } 91 return (ret); 92 } 93 94 int 95 _pthread_spin_trylock(pthread_spinlock_t *lock) 96 { 97 struct pthread_spinlock *lck; 98 99 if (lock == NULL || *lock == NULL) 100 return (EINVAL); 101 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 102 if (lck == NULL) 103 return (EINVAL); 104 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock)); 105 } 106 107 int 108 _pthread_spin_lock(pthread_spinlock_t *lock) 109 { 110 struct pthread *curthread; 111 struct pthread_spinlock *lck; 112 int count; 113 114 if (lock == NULL) 115 return (EINVAL); 116 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 117 if (lck == NULL) 118 return (EINVAL); 119 120 curthread = _get_curthread(); 121 count = SPIN_COUNT; 122 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) { 123 while (lck->s_lock.m_owner) { 124 if (!_thr_is_smp) { 125 _pthread_yield(); 126 } else { 127 CPU_SPINWAIT; 128 if (--count <= 0) { 129 count = SPIN_COUNT; 130 _pthread_yield(); 131 } 132 } 133 } 134 } 135 return (0); 136 } 137 138 int 139 _pthread_spin_unlock(pthread_spinlock_t *lock) 140 { 141 struct pthread_spinlock *lck; 142 143 if (lock == NULL) 144 return (EINVAL); 145 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 146 if (lck == NULL) 147 return (EINVAL); 148 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock)); 149 } 150