1/*	$NetBSD: mutex.h,v 1.2 2007/12/29 15:44:31 jmcneill Exp $	*/
2
3/*-
4 * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe and Andrew Doran.
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 _ARCH_USERMODE_INCLUDE_MUTEX_H_
33#define	_ARCH_USERMODE_INCLUDE_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#define	mtx_owner 			u.mtxa_owner
52#define	mtx_ipl 			u.s.mtxs_ipl
53#define	mtx_lock			u.s.mtxs_lock
54
55#define	__HAVE_SIMPLE_MUTEXES		1
56
57/*
58 * MUTEX_RECEIVE: no memory barrier required, as 'ret' implies a load fence.
59 */
60#define	MUTEX_RECEIVE(mtx)		/* nothing */
61
62/*
63 * MUTEX_GIVE: no memory barrier required, as _lock_cas() will take care of it.
64 */
65#define	MUTEX_GIVE(mtx)			/* nothing */
66
67#define	MUTEX_CAS(p, o, n)		\
68    (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o))
69
70unsigned long	_atomic_cas_ulong(volatile unsigned long *,
71    unsigned long, unsigned long);
72
73#endif	/* __MUTEX_PRIVATE */
74
75#endif /* _ARCH_USERMODE_INCLUDE_MUTEX_H_ */
76