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 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 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 __thr_spinunlock(spinlock_t *lck) 65 { 66 struct spinlock_extra *_extra; 67 68 _extra = lck->thr_extra; 69 THR_UMUTEX_UNLOCK(_get_curthread(), &_extra->lock); 70 } 71 72 void 73 __thr_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->thr_extra == NULL) 82 init_spinlock(lck); 83 _extra = lck->thr_extra; 84 THR_UMUTEX_LOCK(_get_curthread(), &_extra->lock); 85 } 86 87 static void 88 init_spinlock(spinlock_t *lck) 89 { 90 struct pthread *curthread = _get_curthread(); 91 92 THR_UMUTEX_LOCK(curthread, &spinlock_static_lock); 93 if ((lck->thr_extra == NULL) && (spinlock_count < MAX_SPINLOCKS)) { 94 lck->thr_extra = &extra[spinlock_count]; 95 _thr_umutex_init(&extra[spinlock_count].lock); 96 extra[spinlock_count].owner = lck; 97 spinlock_count++; 98 } 99 THR_UMUTEX_UNLOCK(curthread, &spinlock_static_lock); 100 if (lck->thr_extra == NULL) 101 PANIC("Warning: exceeded max spinlocks"); 102 } 103 104 void 105 _thr_spinlock_init(void) 106 { 107 int i; 108 109 _thr_umutex_init(&spinlock_static_lock); 110 if (initialized != 0) { 111 /* 112 * called after fork() to reset state of libc spin locks, 113 * it is not quite right since libc may be in inconsistent 114 * state, resetting the locks to allow current thread to be 115 * able to hold them may not help things too much, but 116 * anyway, we do our best. 117 * it is better to do pthread_atfork in libc. 118 */ 119 for (i = 0; i < spinlock_count; i++) 120 _thr_umutex_init(&extra[i].lock); 121 } else { 122 initialized = 1; 123 } 124 } 125