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 <sys/cdefs.h> 34 #include "namespace.h" 35 #include <errno.h> 36 #include <stdlib.h> 37 #include <pthread.h> 38 #include "un-namespace.h" 39 40 #include "thr_private.h" 41 42 _Static_assert(sizeof(struct pthread_spinlock) <= THR_PAGE_SIZE_MIN, 43 "pthread_spinlock is too large for off-page"); 44 45 #define SPIN_COUNT 100000 46 47 __weak_reference(_pthread_spin_init, pthread_spin_init); 48 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy); 49 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock); 50 __weak_reference(_pthread_spin_lock, pthread_spin_lock); 51 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock); 52 53 int 54 _pthread_spin_init(pthread_spinlock_t *lock, int pshared) 55 { 56 struct pthread_spinlock *lck; 57 58 if (lock == NULL) 59 return (EINVAL); 60 if (pshared == PTHREAD_PROCESS_PRIVATE) { 61 lck = aligned_alloc(CACHE_LINE_SIZE, 62 roundup(sizeof(struct pthread_spinlock), CACHE_LINE_SIZE)); 63 if (lck == NULL) 64 return (ENOMEM); 65 *lock = lck; 66 } else if (pshared == PTHREAD_PROCESS_SHARED) { 67 lck = __thr_pshared_offpage(lock, 1); 68 if (lck == NULL) 69 return (EFAULT); 70 *lock = THR_PSHARED_PTR; 71 } else { 72 return (EINVAL); 73 } 74 _thr_umutex_init(&lck->s_lock); 75 return (0); 76 } 77 78 int 79 _pthread_spin_destroy(pthread_spinlock_t *lock) 80 { 81 void *l; 82 int ret; 83 84 if (lock == NULL || *lock == NULL) { 85 ret = EINVAL; 86 } else if (*lock == THR_PSHARED_PTR) { 87 l = __thr_pshared_offpage(lock, 0); 88 if (l != NULL) 89 __thr_pshared_destroy(l); 90 ret = 0; 91 } else { 92 free(*lock); 93 *lock = NULL; 94 ret = 0; 95 } 96 return (ret); 97 } 98 99 int 100 _pthread_spin_trylock(pthread_spinlock_t *lock) 101 { 102 struct pthread_spinlock *lck; 103 104 if (lock == NULL || *lock == NULL) 105 return (EINVAL); 106 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 107 if (lck == NULL) 108 return (EINVAL); 109 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock)); 110 } 111 112 int 113 _pthread_spin_lock(pthread_spinlock_t *lock) 114 { 115 struct pthread *curthread; 116 struct pthread_spinlock *lck; 117 int count; 118 119 if (lock == NULL) 120 return (EINVAL); 121 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 122 if (lck == NULL) 123 return (EINVAL); 124 125 curthread = _get_curthread(); 126 count = SPIN_COUNT; 127 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) { 128 while (lck->s_lock.m_owner) { 129 if (!_thr_is_smp) { 130 _pthread_yield(); 131 } else { 132 CPU_SPINWAIT; 133 if (--count <= 0) { 134 count = SPIN_COUNT; 135 _pthread_yield(); 136 } 137 } 138 } 139 } 140 return (0); 141 } 142 143 int 144 _pthread_spin_unlock(pthread_spinlock_t *lock) 145 { 146 struct pthread_spinlock *lck; 147 148 if (lock == NULL) 149 return (EINVAL); 150 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; 151 if (lck == NULL) 152 return (EINVAL); 153 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock)); 154 } 155