mutex.h revision 1.3 
1/*	$NetBSD: mutex.h,v 1.3 2008/04/28 20:23:25 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Takayoshi Kochi.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _IA64_MUTEX_H_
33#define	_IA64_MUTEX_H_
34
35struct kmutex {
36	union {
37		volatile uintptr_t	mtxa_owner;
38#ifdef __MUTEX_PRIVATE
39		struct {
40			volatile uint8_t	mtxs_dummy;
41			ipl_cookie_t		mtxs_ipl;
42			__cpu_simple_lock_t	mtxs_lock;
43			volatile uint8_t	mtxs_unused;
44		} s;
45#endif
46	} u;
47};
48
49#ifdef __MUTEX_PRIVATE
50
51/* uintptr_t */
52#define	mtx_owner	u.mtxa_owner
53/* ipl_cookie_t */
54#define	mtx_ipl		u.s.mtxs_ipl
55/* __cpu_simple_lock_t */
56#define	mtx_lock	u.s.mtxs_lock
57
58/* XXX when we implement mutex_enter()/mutex_exit(), uncomment this
59#define __HAVE_MUTEX_STUBS		1
60*/
61/* XXX when we implement mutex_spin_enter()/mutex_spin_exit(), uncomment this
62#define __HAVE_SPIN_MUTEX_STUBS		1
63*/
64#define	__HAVE_SIMPLE_MUTEXES		1
65
66/*
67 * MUTEX_RECEIVE: no memory barrier required, atomic_cas implies a load fence.
68 */
69#define	MUTEX_RECEIVE(mtx)		/* nothing */
70
71/*
72 * MUTEX_GIVE: no memory barrier required, as _lock_cas() will take care of it.
73 */
74#define	MUTEX_GIVE(mtx)			/* nothing */
75
76#define	MUTEX_CAS(ptr, old, new)		\
77    (atomic_cas_ulong((volatile unsigned long *)(ptr), (old), (new)) == (old))
78
79#endif	/* __MUTEX_PRIVATE */
80
81#endif	/* _IA64_MUTEX_H_ */
82