1 /*-
2  * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
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  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $DragonFly: src/lib/libthread_xu/thread/thr_umtx.h,v 1.5 2008/04/14 20:12:41 dillon Exp $
27  */
28 
29 #ifndef _THR_DFLY_UMTX_H_
30 #define _THR_DFLY_UMTX_H_
31 
32 #include <unistd.h>
33 
34 #define	UMTX_LOCKED	1
35 #define UMTX_CONTESTED	2
36 
37 typedef int umtx_t;
38 
39 int	__thr_umtx_lock(volatile umtx_t *mtx, int timo);
40 int	__thr_umtx_timedlock(volatile umtx_t *mtx,
41 		 const struct timespec *timeout);
42 void	__thr_umtx_unlock(volatile umtx_t *mtx);
43 
44 static inline void
45 _thr_umtx_init(volatile umtx_t *mtx)
46 {
47     *mtx = 0;
48 }
49 
50 static inline int
51 _thr_umtx_trylock(volatile umtx_t *mtx, int id __unused)
52 {
53     if (atomic_cmpset_acq_int(mtx, 0, 1))
54 	return (0);
55     return (EBUSY);
56 }
57 
58 static inline int
59 _thr_umtx_lock(volatile umtx_t *mtx, int id __unused)
60 {
61     if (atomic_cmpset_acq_int(mtx, 0, 1))
62 	return (0);
63     return (__thr_umtx_lock(mtx, 0));
64 }
65 
66 static inline int
67 _thr_umtx_timedlock(volatile umtx_t *mtx, int id __unused,
68     const struct timespec *timeout)
69 {
70     if (atomic_cmpset_acq_int(mtx, 0, 1))
71 	return (0);
72     return (__thr_umtx_timedlock(mtx, timeout));
73 }
74 
75 static inline void
76 _thr_umtx_unlock(volatile umtx_t *mtx, int id __unused)
77 {
78     if (atomic_cmpset_acq_int(mtx, 1, 0))
79 	return;
80     __thr_umtx_unlock(mtx);
81 }
82 
83 int _thr_umtx_wait(volatile umtx_t *mtx, umtx_t exp,
84 		   const struct timespec *timeout, int clockid);
85 void _thr_umtx_wake(volatile umtx_t *mtx, int count);
86 
87 #endif
88