1 /* 2 * Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the author nor the names of any co-contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 * 31 */ 32 33 #include <sys/types.h> 34 #include <pthread.h> 35 #include <libc_private.h> 36 #include <spinlock.h> 37 38 #include "thr_private.h" 39 40 #define MAX_SPINLOCKS 72 41 42 /* 43 * These data structures are used to trace all spinlocks 44 * in libc. 45 */ 46 struct spinlock_extra { 47 spinlock_t *owner; 48 struct umutex lock; 49 }; 50 51 static struct umutex spinlock_static_lock = DEFAULT_UMUTEX; 52 static struct spinlock_extra extra[MAX_SPINLOCKS]; 53 static int spinlock_count; 54 static int initialized; 55 56 static void init_spinlock(spinlock_t *lck); 57 58 /* 59 * These are for compatability only. Spinlocks of this type 60 * are deprecated. 61 */ 62 63 void 64 _spinunlock(spinlock_t *lck) 65 { 66 struct spinlock_extra *_extra; 67 68 _extra = (struct spinlock_extra *)lck->fname; 69 THR_UMUTEX_UNLOCK(_get_curthread(), &_extra->lock); 70 } 71 72 void 73 _spinlock(spinlock_t *lck) 74 { 75 struct spinlock_extra *_extra; 76 77 if (!__isthreaded) 78 PANIC("Spinlock called when not threaded."); 79 if (!initialized) 80 PANIC("Spinlocks not initialized."); 81 if (lck->fname == NULL) 82 init_spinlock(lck); 83 _extra = (struct spinlock_extra *)lck->fname; 84 THR_UMUTEX_LOCK(_get_curthread(), &_extra->lock); 85 } 86 87 void 88 _spinlock_debug(spinlock_t *lck, char *fname __unused, int lineno __unused) 89 { 90 _spinlock(lck); 91 } 92 93 static void 94 init_spinlock(spinlock_t *lck) 95 { 96 struct pthread *curthread = _get_curthread(); 97 98 THR_UMUTEX_LOCK(curthread, &spinlock_static_lock); 99 if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) { 100 lck->fname = (char *)&extra[spinlock_count]; 101 _thr_umutex_init(&extra[spinlock_count].lock); 102 extra[spinlock_count].owner = lck; 103 spinlock_count++; 104 } 105 THR_UMUTEX_UNLOCK(curthread, &spinlock_static_lock); 106 if (lck->fname == NULL) 107 PANIC("Warning: exceeded max spinlocks"); 108 } 109 110 void 111 _thr_spinlock_init(void) 112 { 113 int i; 114 115 _thr_umutex_init(&spinlock_static_lock); 116 if (initialized != 0) { 117 /* 118 * called after fork() to reset state of libc spin locks, 119 * it is not quite right since libc may be in inconsistent 120 * state, resetting the locks to allow current thread to be 121 * able to hold them may not help things too much, but 122 * anyway, we do our best. 123 * it is better to do pthread_atfork in libc. 124 */ 125 for (i = 0; i < spinlock_count; i++) 126 _thr_umutex_init(&extra[i].lock); 127 } else { 128 initialized = 1; 129 } 130 } 131