1 /* $NetBSD: pthread_spin.c,v 1.6 2012/08/16 04:49:47 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 2001, 2006, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Nathan J. Williams and Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Public (POSIX-specified) spinlocks. 34 */ 35 36 #include <sys/cdefs.h> 37 __RCSID("$NetBSD: pthread_spin.c,v 1.6 2012/08/16 04:49:47 matt Exp $"); 38 39 #include <sys/types.h> 40 #include <sys/ras.h> 41 42 #include <machine/lock.h> 43 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 49 #include "pthread.h" 50 #include "pthread_int.h" 51 52 int 53 pthread_spin_init(pthread_spinlock_t *lock, int pshared) 54 { 55 56 #ifdef ERRORCHECK 57 if (lock == NULL || (pshared != PTHREAD_PROCESS_PRIVATE && 58 pshared != PTHREAD_PROCESS_SHARED)) 59 return EINVAL; 60 #endif 61 lock->pts_magic = _PT_SPINLOCK_MAGIC; 62 63 /* 64 * We don't actually use the pshared flag for anything; 65 * CPU simple locks have all the process-shared properties 66 * that we want anyway. 67 */ 68 lock->pts_flags = pshared; 69 pthread_lockinit(&lock->pts_spin); 70 71 return 0; 72 } 73 74 int 75 pthread_spin_destroy(pthread_spinlock_t *lock) 76 { 77 78 #ifdef ERRORCHECK 79 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 80 return EINVAL; 81 if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin)) 82 return EBUSY; 83 #endif 84 85 lock->pts_magic = _PT_SPINLOCK_DEAD; 86 87 return 0; 88 } 89 90 int 91 pthread_spin_lock(pthread_spinlock_t *lock) 92 { 93 pthread_t self; 94 95 #ifdef ERRORCHECK 96 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 97 return EINVAL; 98 #endif 99 100 self = pthread__self(); 101 while (pthread__spintrylock(self, &lock->pts_spin) == 0) { 102 pthread__smt_pause(); 103 } 104 105 return 0; 106 } 107 108 int 109 pthread_spin_trylock(pthread_spinlock_t *lock) 110 { 111 pthread_t self; 112 113 #ifdef ERRORCHECK 114 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 115 return EINVAL; 116 #endif 117 118 self = pthread__self(); 119 if (pthread__spintrylock(self, &lock->pts_spin) == 0) 120 return EBUSY; 121 return 0; 122 } 123 124 int 125 pthread_spin_unlock(pthread_spinlock_t *lock) 126 { 127 pthread_t self; 128 129 #ifdef ERRORCHECK 130 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 131 return EINVAL; 132 #endif 133 134 self = pthread__self(); 135 pthread__spinunlock(self, &lock->pts_spin); 136 pthread__smt_wake(); 137 138 return 0; 139 } 140