umtx.h revision 162536 
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 162536 2006-09-22 00:52:54Z davidxu $
27 *
28 */
29
30#ifndef _SYS_UMTX_H_
31#define	_SYS_UMTX_H_
32
33#include <sys/_types.h>
34#include <sys/limits.h>
35
36/*
37 * See pthread_*
38 */
39
40#define	UMTX_UNOWNED	0x0
41#define	UMTX_CONTESTED	LONG_MIN
42
43struct umtx {
44	uintptr_t	u_owner;	/* Owner of the mutex. */
45};
46
47#define USYNC_PROCESS_SHARED	0x0001	/* Process shared sync objs */
48
49#define	UMUTEX_UNOWNED		0x0
50#define	UMUTEX_CONTESTED	0x80000000
51
52#define UMUTEX_ERROR_CHECK	0x0002	/* Error-checking mutex */
53#define UMUTEX_PRIO_INHERIT	0x0004	/* Priority inherited mutex */
54#define UMUTEX_PRIO_PROTECT	0x0008	/* Priority protect mutex */
55struct umutex {
56	__lwpid_t	m_owner;	/* Owner of the mutex */
57	uint32_t	m_flags;	/* Flags of the mutex */
58	uint32_t	m_ceilings[2];	/* Priority protect ceiling */
59	uint32_t	m_spare[4];	/* Spare space */
60};
61
62/* op code for _umtx_op */
63#define UMTX_OP_LOCK		0
64#define UMTX_OP_UNLOCK		1
65#define UMTX_OP_WAIT		2
66#define UMTX_OP_WAKE		3
67#define UMTX_OP_MUTEX_TRYLOCK	4
68#define UMTX_OP_MUTEX_LOCK	5
69#define UMTX_OP_MUTEX_UNLOCK	6
70#define UMTX_OP_SET_CEILING	7
71#define UMTX_OP_MAX		8
72
73#ifndef _KERNEL
74
75/*
76 * System call for userland mutex operations.
77 * Bug: assume sizeof(uintptr_t) == sizeof(long)
78 */
79int _umtx_op(void *obj, int op, uintptr_t val, void *uaddr, void *uaddr2);
80
81/*
82 * Old (deprecated) userland mutex system calls.
83 */
84int _umtx_lock(struct umtx *mtx);
85int _umtx_unlock(struct umtx *mtx);
86
87/*
88 * Standard api.  Try uncontested acquire/release and asks the
89 * kernel to resolve failures.
90 */
91static __inline void
92umtx_init(struct umtx *umtx)
93{
94	umtx->u_owner = UMTX_UNOWNED;
95}
96
97static __inline uintptr_t
98umtx_owner(struct umtx *umtx)
99{
100	return (umtx->u_owner & ~LONG_MIN);
101}
102
103static __inline int
104umtx_lock(struct umtx *umtx, uintptr_t id)
105{
106	if (atomic_cmpset_acq_ptr(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
107		if (_umtx_lock(umtx) == -1)
108			return (errno);
109	return (0);
110}
111
112static __inline int
113umtx_trylock(struct umtx *umtx, uintptr_t id)
114{
115	if (atomic_cmpset_acq_ptr(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
116		return (EBUSY);
117	return (0);
118}
119
120static __inline int
121umtx_timedlock(struct umtx *umtx, uintptr_t id, const struct timespec *timeout)
122{
123	if (atomic_cmpset_acq_ptr(&umtx->u_owner, UMTX_UNOWNED, id) == 0)
124		if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0,
125		    __DECONST(void *, timeout)) == -1)
126			return (errno);
127	return (0);
128}
129
130static __inline int
131umtx_unlock(struct umtx *umtx, uintptr_t id)
132{
133	if (atomic_cmpset_rel_ptr(&umtx->u_owner, id, UMTX_UNOWNED) == 0)
134		if (_umtx_unlock(umtx) == -1)
135			return (errno);
136	return (0);
137}
138
139static __inline int
140umtx_wait(long *p, long val, const struct timespec *timeout)
141{
142	if (_umtx_op(p, UMTX_OP_WAIT, val, 0,
143	    __DECONST(void *, timeout)) == -1)
144		return (errno);
145	return (0);
146}
147
148/* Wake threads waiting on a user address. */
149static __inline int
150umtx_wake(long *p, int nr_wakeup)
151{
152	if (_umtx_op(p, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
153		return (errno);
154	return (0);
155}
156
157#else
158
159struct thread;
160
161struct umtx_q *umtxq_alloc(void);
162void umtxq_free(struct umtx_q *);
163int kern_umtx_wake(struct thread *td, void *uaddr, int n_wake);
164void umtx_pi_adjust(struct thread *td, u_char oldpri);
165void umtx_thread_init(struct thread *td);
166void umtx_thread_fini(struct thread *td);
167void umtx_thread_alloc(struct thread *td);
168void umtx_thread_exit(struct thread *td);
169#endif /* !_KERNEL */
170#endif /* !_SYS_UMTX_H_ */
171