1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 "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 _Static_assert(sizeof(struct pthread_spinlock) <= THR_PAGE_SIZE_MIN, 42 "pthread_spinlock is too large for off-page"); 43 44 #define SPIN_COUNT 100000 45 46 __weak_reference(_pthread_spin_init, pthread_spin_init); 47 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 48 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 49 __weak_reference(_pthread_spin_lock, pthread_spin_lock); 50 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 51 52 int 53 _pthread_spin_init(pthread_spinlock_t *lock, int pshared) 54 { 55 struct pthread_spinlock *lck; 56 57 if (lock == NULL) 58 return (EINVAL); 59 if (pshared == PTHREAD_PROCESS_PRIVATE) { 60 lck = aligned_alloc(CACHE_LINE_SIZE, 61 roundup(sizeof(struct pthread_spinlock), CACHE_LINE_SIZE)); 62 if (lck == NULL) 63 return (ENOMEM); 64 *lock = lck; 65 } else if (pshared == PTHREAD_PROCESS_SHARED) { 66 lck = __thr_pshared_offpage(lock, 1); 67 if (lck == NULL) 68 return (EFAULT); 69 *lock = THR_PSHARED_PTR; 70 } else { 71 return (EINVAL); 72 } 73 _thr_umutex_init(&lck->s_lock); 74 return (0); 75 } 76 77 int 78 _pthread_spin_destroy(pthread_spinlock_t *lock) 79 { 80 void *l; 81 int ret; 82 83 if (lock == NULL || *lock == NULL) { 84 ret = EINVAL; 85 } else if (*lock == THR_PSHARED_PTR) { 86 l = __thr_pshared_offpage(lock, 0); 87 if (l != NULL) 88 __thr_pshared_destroy(l); 89 ret = 0; 90 } else { 91 free(*lock); 92 *lock = NULL; 93 ret = 0; 94 } 95 return (ret); 96 } 97 98 int 99 _pthread_spin_trylock(pthread_spinlock_t *lock) 100 { 101 struct pthread_spinlock *lck; 102 103 if (lock == NULL || *lock == NULL) 104 return (EINVAL); 105 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 106 if (lck == NULL) 107 return (EINVAL); 108 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock)); 109 } 110 111 int 112 _pthread_spin_lock(pthread_spinlock_t *lock) 113 { 114 struct pthread *curthread; 115 struct pthread_spinlock *lck; 116 int count; 117 118 if (lock == NULL) 119 return (EINVAL); 120 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 121 if (lck == NULL) 122 return (EINVAL); 123 124 curthread = _get_curthread(); 125 count = SPIN_COUNT; 126 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) { 127 while (lck->s_lock.m_owner) { 128 if (!_thr_is_smp) { 129 _pthread_yield(); 130 } else { 131 CPU_SPINWAIT; 132 if (--count <= 0) { 133 count = SPIN_COUNT; 134 _pthread_yield(); 135 } 136 } 137 } 138 } 139 return (0); 140 } 141 142 int 143 _pthread_spin_unlock(pthread_spinlock_t *lock) 144 { 145 struct pthread_spinlock *lck; 146 147 if (lock == NULL) 148 return (EINVAL); 149 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 150 if (lck == NULL) 151 return (EINVAL); 152 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock)); 153 } 154