umtx.h revision 157211 
1/*-
2 * Copyright (c) 2002, Jeffrey Roberson <jeff@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 unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/sys/umtx.h 157211 2006-03-28 14:32:38Z des $
27 *
28 */
29
30#ifndef _SYS_UMTX_H_
31#define	_SYS_UMTX_H_
32
33#include <sys/limits.h>
34
35/*
36 * See pthread_*
37 */
38
39#define	UMTX_UNOWNED	0x0
40#define	UMTX_CONTESTED	LONG_MIN
41
42struct umtx {
43	void	*u_owner;	/* Owner of the mutex. */
44};
45
46/* op code for _umtx_op */
47#define UMTX_OP_LOCK		0
48#define UMTX_OP_UNLOCK		1
49#define UMTX_OP_WAIT		2
50#define UMTX_OP_WAKE		3
51
52#ifndef _KERNEL
53
54/*
55 * System call for userland mutex operations.
56 */
57int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr, void *uaddr2);
58
59/*
60 * Old (deprecated) userland mutex system calls.
61 */
62int _umtx_lock(struct umtx *mtx);
63int _umtx_unlock(struct umtx *mtx);
64
65/*
66 * Standard api.  Try uncontested acquire/release and asks the
67 * kernel to resolve failures.
68 */
69static __inline void
70umtx_init(struct umtx *umtx)
71{
72	umtx->u_owner = UMTX_UNOWNED;
73}
74
75static __inline long
76umtx_owner(struct umtx *umtx)
77{
78	return ((long)umtx->u_owner & ~LONG_MIN);
79}
80
81static __inline int
82umtx_lock(struct umtx *umtx, long id)
83{
84	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
85	    (void *)id) == 0)
86		if (_umtx_lock(umtx) == -1)
87			return (errno);
88	return (0);
89}
90
91static __inline int
92umtx_trylock(struct umtx *umtx, long id)
93{
94	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
95	    (void *)id) == 0)
96		return (EBUSY);
97	return (0);
98}
99
100static __inline int
101umtx_timedlock(struct umtx *umtx, long id, const struct timespec *timeout)
102{
103	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
104	    (void *)id) == 0)
105		if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0,
106		    __DECONST(void *, timeout)) == -1)
107			return (errno);
108	return (0);
109}
110
111static __inline int
112umtx_unlock(struct umtx *umtx, long id)
113{
114	if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
115	    (void *)UMTX_UNOWNED) == 0)
116		if (_umtx_unlock(umtx) == -1)
117			return (errno);
118	return (0);
119}
120
121static __inline int
122umtx_wait(struct umtx *umtx, long id, const struct timespec *timeout)
123{
124	if (_umtx_op(umtx, UMTX_OP_WAIT, id, 0,
125	    __DECONST(void *, timeout)) == -1)
126		return (errno);
127	return (0);
128}
129
130/* Wake threads waiting on a user address. */
131static __inline int
132umtx_wake(struct umtx *umtx, int nr_wakeup)
133{
134	if (_umtx_op(umtx, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
135		return (errno);
136	return (0);
137}
138#else
139
140struct umtx_q *umtxq_alloc(void);
141void umtxq_free(struct umtx_q *);
142struct thread;
143int kern_umtx_wake(struct thread *td, void *uaddr, int n_wake);
144
145#endif /* !_KERNEL */
146#endif /* !_SYS_UMTX_H_ */
147