xref: /freebsd/lib/libthr/thread/thr_spinlock.c (revision 8955220107ad0905239fd45ff88ffa1525223974)
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. 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.
19  *
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
30  * SUCH DAMAGE.
31  *
32  * $FreeBSD$
33  *
34  */
35 
36 #include <stdlib.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include <sched.h>
40 #include <pthread.h>
41 #include <unistd.h>
42 
43 #include <libc_private.h>
44 
45 #include "thr_private.h"
46 
47 void
48 _spinunlock(spinlock_t *lck)
49 {
50 	if (umtx_unlock((struct umtx *)lck, curthread->thr_id))
51 		abort();
52 }
53 
54 /*
55  * Lock a location for the running thread. Yield to allow other
56  * threads to run if this thread is blocked because the lock is
57  * not available. Note that this function does not sleep. It
58  * assumes that the lock will be available very soon.
59  */
60 void
61 _spinlock(spinlock_t *lck)
62 {
63 	if (umtx_lock((struct umtx *)lck, curthread->thr_id))
64 		abort();
65 }
66 
67 int
68 _spintrylock(spinlock_t *lck)
69 {
70 	int error;
71 
72 	error = umtx_lock((struct umtx *)lck, curthread->thr_id);
73 	if (error != 0 && error != EBUSY)
74 		abort();
75 	return (error);
76 }
77 
78 /*
79  * Lock a location for the running thread. Yield to allow other
80  * threads to run if this thread is blocked because the lock is
81  * not available. Note that this function does not sleep. It
82  * assumes that the lock will be available very soon.
83  *
84  * This function checks if the running thread has already locked the
85  * location, warns if this occurs and creates a thread dump before
86  * returning.
87  */
88 void
89 _spinlock_debug(spinlock_t *lck, char *fname, int lineno)
90 {
91 	if (umtx_lock((struct umtx *)lck, curthread->thr_id))
92 		abort();
93 }
94