1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2003 David Xu <davidxu@freebsd.org> 5 * Copyright (c) 2016 The FreeBSD Foundation 6 * All rights reserved. 7 * 8 * Portions of this software were developed by Konstantin Belousov 9 * under sponsorship from the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <errno.h> 38 #include <stdlib.h> 39 #include <pthread.h> 40 #include "un-namespace.h" 41 42 #include "thr_private.h" 43 44 _Static_assert(sizeof(struct pthread_spinlock) <= PAGE_SIZE, 45 "pthread_spinlock is too large for off-page"); 46 47 #define SPIN_COUNT 100000 48 49 __weak_reference(_pthread_spin_init, pthread_spin_init); 50 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 51 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 52 __weak_reference(_pthread_spin_lock, pthread_spin_lock); 53 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 54 55 int 56 _pthread_spin_init(pthread_spinlock_t *lock, int pshared) 57 { 58 struct pthread_spinlock *lck; 59 60 if (lock == NULL) 61 return (EINVAL); 62 if (pshared == PTHREAD_PROCESS_PRIVATE) { 63 lck = malloc(sizeof(struct pthread_spinlock)); 64 if (lck == NULL) 65 return (ENOMEM); 66 *lock = lck; 67 } else if (pshared == PTHREAD_PROCESS_SHARED) { 68 lck = __thr_pshared_offpage(lock, 1); 69 if (lck == NULL) 70 return (EFAULT); 71 *lock = THR_PSHARED_PTR; 72 } else { 73 return (EINVAL); 74 } 75 _thr_umutex_init(&lck->s_lock); 76 return (0); 77 } 78 79 int 80 _pthread_spin_destroy(pthread_spinlock_t *lock) 81 { 82 void *l; 83 int ret; 84 85 if (lock == NULL || *lock == NULL) { 86 ret = EINVAL; 87 } else if (*lock == THR_PSHARED_PTR) { 88 l = __thr_pshared_offpage(lock, 0); 89 if (l != NULL) 90 __thr_pshared_destroy(l); 91 ret = 0; 92 } else { 93 free(*lock); 94 *lock = NULL; 95 ret = 0; 96 } 97 return (ret); 98 } 99 100 int 101 _pthread_spin_trylock(pthread_spinlock_t *lock) 102 { 103 struct pthread_spinlock *lck; 104 105 if (lock == NULL || *lock == NULL) 106 return (EINVAL); 107 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 108 if (lck == NULL) 109 return (EINVAL); 110 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock)); 111 } 112 113 int 114 _pthread_spin_lock(pthread_spinlock_t *lock) 115 { 116 struct pthread *curthread; 117 struct pthread_spinlock *lck; 118 int count; 119 120 if (lock == NULL) 121 return (EINVAL); 122 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 123 if (lck == NULL) 124 return (EINVAL); 125 126 curthread = _get_curthread(); 127 count = SPIN_COUNT; 128 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) { 129 while (lck->s_lock.m_owner) { 130 if (!_thr_is_smp) { 131 _pthread_yield(); 132 } else { 133 CPU_SPINWAIT; 134 if (--count <= 0) { 135 count = SPIN_COUNT; 136 _pthread_yield(); 137 } 138 } 139 } 140 } 141 return (0); 142 } 143 144 int 145 _pthread_spin_unlock(pthread_spinlock_t *lock) 146 { 147 struct pthread_spinlock *lck; 148 149 if (lock == NULL) 150 return (EINVAL); 151 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 152 if (lck == NULL) 153 return (EINVAL); 154 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock)); 155 } 156