lock.h revision 1.12 
1/*	$NetBSD: lock.h,v 1.12 2008/04/28 20:23:32 martin 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 *
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/*
33 * Machine-dependent spin lock operations.
34 */
35
36#ifndef _POWERPC_LOCK_H_
37#define _POWERPC_LOCK_H_
38
39static __inline int
40__SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
41{
42	return *__ptr == __SIMPLELOCK_LOCKED;
43}
44
45static __inline int
46__SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
47{
48	return *__ptr == __SIMPLELOCK_UNLOCKED;
49}
50
51static __inline void
52__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
53{
54	*__ptr = __SIMPLELOCK_UNLOCKED;
55}
56
57static __inline void
58__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
59{
60	*__ptr = __SIMPLELOCK_LOCKED;
61}
62
63static __inline void
64__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
65{
66	*alp = __SIMPLELOCK_UNLOCKED;
67	__asm volatile ("sync");
68}
69
70static __inline void
71__cpu_simple_lock(__cpu_simple_lock_t *alp)
72{
73	int old;
74
75	__asm volatile ("	\
76				\n\
771:	lwarx	%0,0,%1		\n\
78	cmpwi	%0,%2		\n\
79	beq+	3f		\n\
802:	lwzx	%0,0,%1		\n\
81	cmpwi	%0,%2		\n\
82	beq+	1b		\n\
83	b	2b		\n\
843:	stwcx.	%3,0,%1		\n\
85	bne-	1b		\n\
86	isync			\n\
87				\n"
88	: "=&r"(old)
89	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
90	: "memory");
91}
92
93static __inline int
94__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
95{
96	int old, dummy;
97
98	__asm volatile ("	\
99				\n\
1001:	lwarx	%0,0,%1		\n\
101	cmpwi	%0,%2		\n\
102	bne	2f		\n\
103	stwcx.	%3,0,%1		\n\
104	bne-	1b		\n\
1052:	stwcx.	%3,0,%4		\n\
106	isync			\n\
107				\n"
108	: "=&r"(old)
109	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
110	  "r"(&dummy)
111	: "memory");
112
113	return (old == __SIMPLELOCK_UNLOCKED);
114}
115
116static __inline void
117__cpu_simple_unlock(__cpu_simple_lock_t *alp)
118{
119	__asm volatile ("sync");
120	*alp = __SIMPLELOCK_UNLOCKED;
121}
122
123static __inline void
124mb_read(void)
125{
126	__asm volatile ("isync" ::: "memory");
127}
128
129static __inline void
130mb_write(void)
131{
132	__asm volatile ("sync" ::: "memory");
133}
134
135static __inline void
136mb_memory(void)
137{
138	__asm volatile ("sync" ::: "memory");
139}
140
141#endif /* _POWERPC_LOCK_H_ */
142