lock.h revision 1.11 
1/*	$NetBSD: lock.h,v 1.11 2007/10/17 19:56:41 garbled Exp $	*/
2
3/*-
4 * Copyright (c) 2000, 2007 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 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the NetBSD
21 *	Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39/*
40 * Machine-dependent spin lock operations.
41 */
42
43#ifndef _POWERPC_LOCK_H_
44#define _POWERPC_LOCK_H_
45
46static __inline int
47__SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
48{
49	return *__ptr == __SIMPLELOCK_LOCKED;
50}
51
52static __inline int
53__SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
54{
55	return *__ptr == __SIMPLELOCK_UNLOCKED;
56}
57
58static __inline void
59__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
60{
61	*__ptr = __SIMPLELOCK_UNLOCKED;
62}
63
64static __inline void
65__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
66{
67	*__ptr = __SIMPLELOCK_LOCKED;
68}
69
70static __inline void
71__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
72{
73	*alp = __SIMPLELOCK_UNLOCKED;
74	__asm volatile ("sync");
75}
76
77static __inline void
78__cpu_simple_lock(__cpu_simple_lock_t *alp)
79{
80	int old;
81
82	__asm volatile ("	\
83				\n\
841:	lwarx	%0,0,%1		\n\
85	cmpwi	%0,%2		\n\
86	beq+	3f		\n\
872:	lwzx	%0,0,%1		\n\
88	cmpwi	%0,%2		\n\
89	beq+	1b		\n\
90	b	2b		\n\
913:	stwcx.	%3,0,%1		\n\
92	bne-	1b		\n\
93	isync			\n\
94				\n"
95	: "=&r"(old)
96	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
97	: "memory");
98}
99
100static __inline int
101__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
102{
103	int old, dummy;
104
105	__asm volatile ("	\
106				\n\
1071:	lwarx	%0,0,%1		\n\
108	cmpwi	%0,%2		\n\
109	bne	2f		\n\
110	stwcx.	%3,0,%1		\n\
111	bne-	1b		\n\
1122:	stwcx.	%3,0,%4		\n\
113	isync			\n\
114				\n"
115	: "=&r"(old)
116	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
117	  "r"(&dummy)
118	: "memory");
119
120	return (old == __SIMPLELOCK_UNLOCKED);
121}
122
123static __inline void
124__cpu_simple_unlock(__cpu_simple_lock_t *alp)
125{
126	__asm volatile ("sync");
127	*alp = __SIMPLELOCK_UNLOCKED;
128}
129
130static __inline void
131mb_read(void)
132{
133	__asm volatile ("isync" ::: "memory");
134}
135
136static __inline void
137mb_write(void)
138{
139	__asm volatile ("sync" ::: "memory");
140}
141
142static __inline void
143mb_memory(void)
144{
145	__asm volatile ("sync" ::: "memory");
146}
147
148#endif /* _POWERPC_LOCK_H_ */
149