lock.h revision 1.4 
1/*	$NetBSD: lock.h,v 1.4 2000/07/08 04:36:56 tsubai Exp $	*/
2
3/*-
4 * Copyright (c) 2000 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.
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
46typedef __volatile int __cpu_simple_lock_t;
47
48#define __SIMPLELOCK_LOCKED	1
49#define __SIMPLELOCK_UNLOCKED	0
50
51static __inline void
52__cpu_simple_lock_init(__cpu_simple_lock_t *alp)
53{
54	*alp = __SIMPLELOCK_UNLOCKED;
55	__asm __volatile ("sync");
56}
57
58static __inline void
59__cpu_simple_lock(__cpu_simple_lock_t *alp)
60{
61	int old;
62
63	__asm __volatile ("	\
64				\n\
651:	lwarx	%0,0,%1		\n\
66	cmpwi	%0,%2		\n\
67	beq+	3f		\n\
682:	lwzx	%0,0,%1		\n\
69	cmpwi	%0,%2		\n\
70	beq+	1b		\n\
71	b	2b		\n\
723:	stwcx.	%3,0,%1		\n\
73	bne-	1b		\n\
74	isync			\n\
75				\n"
76	: "=&r"(old)
77	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
78	: "memory");
79}
80
81static __inline int
82__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
83{
84	int old, dummy;
85
86	__asm __volatile ("	\
87				\n\
881:	lwarx	%0,0,%1		\n\
89	cmpwi	%0,%2		\n\
90	bne	2f		\n\
91	stwcx.	%3,0,%1		\n\
92	bne-	1b		\n\
932:	stwcx.	%3,0,%4		\n\
94	isync			\n\
95				\n"
96	: "=&r"(old)
97	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
98	  "r"(&dummy)
99	: "memory");
100
101	return (old == __SIMPLELOCK_UNLOCKED);
102}
103
104static __inline void
105__cpu_simple_unlock(__cpu_simple_lock_t *alp)
106{
107	__asm __volatile ("sync");
108	*alp = __SIMPLELOCK_UNLOCKED;
109}
110
111#endif /* _POWERPC_LOCK_H_ */
112