1 /* $NetBSD: pthread_spin.c,v 1.4 2008/01/05 01:37:35 ad 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Public (POSIX-specified) spinlocks. 41 */ 42 43 #include <sys/cdefs.h> 44 __RCSID("$NetBSD: pthread_spin.c,v 1.4 2008/01/05 01:37:35 ad Exp $"); 45 46 #include <sys/types.h> 47 #include <sys/ras.h> 48 49 #include <machine/lock.h> 50 51 #include <errno.h> 52 #include <unistd.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 56 #include "pthread.h" 57 #include "pthread_int.h" 58 59 int 60 pthread_spin_init(pthread_spinlock_t *lock, int pshared) 61 { 62 63 #ifdef ERRORCHECK 64 if (lock == NULL || (pshared != PTHREAD_PROCESS_PRIVATE && 65 pshared != PTHREAD_PROCESS_SHARED)) 66 return EINVAL; 67 #endif 68 lock->pts_magic = _PT_SPINLOCK_MAGIC; 69 70 /* 71 * We don't actually use the pshared flag for anything; 72 * CPU simple locks have all the process-shared properties 73 * that we want anyway. 74 */ 75 lock->pts_flags = pshared; 76 pthread_lockinit(&lock->pts_spin); 77 78 return 0; 79 } 80 81 int 82 pthread_spin_destroy(pthread_spinlock_t *lock) 83 { 84 85 #ifdef ERRORCHECK 86 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 87 return EINVAL; 88 if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin)) 89 return EBUSY; 90 #endif 91 92 lock->pts_magic = _PT_SPINLOCK_DEAD; 93 94 return 0; 95 } 96 97 int 98 pthread_spin_lock(pthread_spinlock_t *lock) 99 { 100 pthread_t self; 101 102 #ifdef ERRORCHECK 103 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 104 return EINVAL; 105 #endif 106 107 self = pthread__self(); 108 while (pthread__spintrylock(self, &lock->pts_spin) == 0) { 109 pthread__smt_pause(); 110 } 111 112 return 0; 113 } 114 115 int 116 pthread_spin_trylock(pthread_spinlock_t *lock) 117 { 118 pthread_t self; 119 120 #ifdef ERRORCHECK 121 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 122 return EINVAL; 123 #endif 124 125 self = pthread__self(); 126 if (pthread__spintrylock(self, &lock->pts_spin) == 0) 127 return EBUSY; 128 return 0; 129 } 130 131 int 132 pthread_spin_unlock(pthread_spinlock_t *lock) 133 { 134 pthread_t self; 135 136 #ifdef ERRORCHECK 137 if (lock == NULL || lock->pts_magic != _PT_SPINLOCK_MAGIC) 138 return EINVAL; 139 #endif 140 141 self = pthread__self(); 142 pthread__spinunlock(self, &lock->pts_spin); 143 144 return 0; 145 } 146