lock.h revision 1.16 
1/*	$NetBSD: lock.h,v 1.16 2021/09/13 11:54:42 rin 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(const __cpu_simple_lock_t *__ptr)
41{
42	return *__ptr == __SIMPLELOCK_LOCKED;
43}
44
45static __inline int
46__SIMPLELOCK_UNLOCKED_P(const __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:				\n"
85#ifdef IBM405_ERRATA77
86	"dcbt	0,%1		\n"
87#endif
88	"stwcx.	%3,0,%1		\n\
89	bne-	1b		\n\
90	isync			\n\
91				\n"
92	: "=&r"(old)
93	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
94	: "memory");
95}
96
97static __inline int
98__cpu_simple_lock_try(__cpu_simple_lock_t *alp)
99{
100	int old, dummy;
101
102	__asm volatile ("	\
103				\n\
1041:	lwarx	%0,0,%1		\n\
105	cmpwi	%0,%2		\n\
106	bne	2f		\n"
107#ifdef IBM405_ERRATA77
108	"dcbt	0,%1		\n"
109#endif
110	"stwcx.	%3,0,%1		\n\
111	bne-	1b		\n\
1122:				\n"
113#ifdef IBM405_ERRATA77
114	"dcbt	0,%4		\n"
115#endif
116	"stwcx.	%3,0,%4		\n\
117	isync			\n\
118				\n"
119	: "=&r"(old)
120	: "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
121	  "r"(&dummy)
122	: "memory");
123
124	return (old == __SIMPLELOCK_UNLOCKED);
125}
126
127static __inline void
128__cpu_simple_unlock(__cpu_simple_lock_t *alp)
129{
130	__asm volatile ("sync");
131	*alp = __SIMPLELOCK_UNLOCKED;
132}
133
134#endif /* _POWERPC_LOCK_H_ */
135