1 /* $NetBSD: lock.h,v 1.17 2022/02/12 17:17:53 riastradh 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
39 static __inline int
__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t * __ptr)40 __SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
41 {
42 return *__ptr == __SIMPLELOCK_LOCKED;
43 }
44
45 static __inline int
__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t * __ptr)46 __SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
47 {
48 return *__ptr == __SIMPLELOCK_UNLOCKED;
49 }
50
51 static __inline void
__cpu_simple_lock_clear(__cpu_simple_lock_t * __ptr)52 __cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
53 {
54 *__ptr = __SIMPLELOCK_UNLOCKED;
55 }
56
57 static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t * __ptr)58 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
59 {
60 *__ptr = __SIMPLELOCK_LOCKED;
61 }
62
63 static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t * alp)64 __cpu_simple_lock_init(__cpu_simple_lock_t *alp)
65 {
66 *alp = __SIMPLELOCK_UNLOCKED;
67 }
68
69 static __inline void
__cpu_simple_lock(__cpu_simple_lock_t * alp)70 __cpu_simple_lock(__cpu_simple_lock_t *alp)
71 {
72 int old;
73
74 __asm volatile (" \
75 \n\
76 1: lwarx %0,0,%1 \n\
77 cmpwi %0,%2 \n\
78 beq+ 3f \n\
79 2: lwzx %0,0,%1 \n\
80 cmpwi %0,%2 \n\
81 beq+ 1b \n\
82 b 2b \n\
83 3: \n"
84 #ifdef IBM405_ERRATA77
85 "dcbt 0,%1 \n"
86 #endif
87 "stwcx. %3,0,%1 \n\
88 bne- 1b \n\
89 isync \n\
90 \n"
91 : "=&r"(old)
92 : "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED)
93 : "memory");
94 }
95
96 static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t * alp)97 __cpu_simple_lock_try(__cpu_simple_lock_t *alp)
98 {
99 int old, dummy;
100
101 __asm volatile (" \
102 \n\
103 1: lwarx %0,0,%1 \n\
104 cmpwi %0,%2 \n\
105 bne 2f \n"
106 #ifdef IBM405_ERRATA77
107 "dcbt 0,%1 \n"
108 #endif
109 "stwcx. %3,0,%1 \n\
110 bne- 1b \n\
111 2: \n"
112 #ifdef IBM405_ERRATA77
113 "dcbt 0,%4 \n"
114 #endif
115 "stwcx. %3,0,%4 \n\
116 isync \n\
117 \n"
118 : "=&r"(old)
119 : "r"(alp), "I"(__SIMPLELOCK_UNLOCKED), "r"(__SIMPLELOCK_LOCKED),
120 "r"(&dummy)
121 : "memory");
122
123 return (old == __SIMPLELOCK_UNLOCKED);
124 }
125
126 static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t * alp)127 __cpu_simple_unlock(__cpu_simple_lock_t *alp)
128 {
129 __asm volatile ("sync");
130 *alp = __SIMPLELOCK_UNLOCKED;
131 }
132
133 #endif /* _POWERPC_LOCK_H_ */
134