2 * Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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
32 * $DragonFly: src/lib/libthread_xu/thread/thr_spinlock.c,v 1.3 2006/04/06 13:03:09 davidxu Exp $
35 #include "namespace.h"
36 #include <sys/types.h>
37 #include <machine/atomic.h>
38 #include <machine/tls.h>
40 #include <libc_private.h>
42 #include "un-namespace.h"
44 #include "thr_private.h"
46 #define MAX_SPINLOCKS 256
49 * These data structures are used to trace all spinlocks
52 struct spinlock_extra {
56 static umtx_t spinlock_static_lock;
57 static struct spinlock_extra extra[MAX_SPINLOCKS];
58 static int spinlock_count;
59 static int initialized;
61 static void init_spinlock(spinlock_t *lck);
64 * These are for compatability only. Spinlocks of this type
69 _spinunlock(spinlock_t *lck)
71 struct pthread *curthread = tls_get_curthread();
73 THR_UMTX_UNLOCK(curthread, (volatile umtx_t *)&lck->access_lock);
77 _spinlock(spinlock_t *lck)
79 struct pthread *curthread;
82 PANIC("Spinlock called when not threaded.");
84 PANIC("Spinlocks not initialized.");
85 if (lck->fname == NULL)
88 curthread = tls_get_curthread();
89 THR_UMTX_LOCK(curthread, (volatile umtx_t *)&lck->access_lock);
93 * Returns 0 on success, else EBUSY
96 _spintrylock(spinlock_t *lck)
98 struct pthread *curthread;
101 PANIC("Spinlock called when not threaded.");
103 PANIC("Spinlocks not initialized.");
104 if (lck->fname == NULL)
107 curthread = tls_get_curthread();
108 return(THR_UMTX_TRYLOCK(curthread,
109 (volatile umtx_t *)&lck->access_lock));
113 _spinlock_debug(spinlock_t *lck, char *fname __unused, int lineno __unused)
119 init_spinlock(spinlock_t *lck)
121 static int count = 0;
122 struct pthread *curthread = tls_get_curthread();
124 THR_UMTX_LOCK(curthread, &spinlock_static_lock);
125 if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
126 lck->fname = (char *)&extra[spinlock_count];
127 extra[spinlock_count].owner = lck;
130 THR_UMTX_UNLOCK(curthread, &spinlock_static_lock);
131 if (lck->fname == NULL && ++count < 5)
132 stderr_debug("Warning: exceeded max spinlocks");
136 _thr_spinlock_init(void)
140 _thr_umtx_init(&spinlock_static_lock);
141 if (initialized != 0) {
143 * called after fork() to reset state of libc spin locks,
144 * it is not quite right since libc may be in inconsistent
145 * state, resetting the locks to allow current thread to be
146 * able to hold them may not help things too much, but
147 * anyway, we do our best.
148 * it is better to do pthread_atfork in libc.
150 for (i = 0; i < spinlock_count; i++)
151 _thr_umtx_init((volatile umtx_t *)
152 &extra[i].owner->access_lock);