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Linux kernel mirror (for testing)
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kernel
os
linux
1/*
2 * PowerPC64 atomic operations
3 *
4 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
5 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#ifndef _ASM_PPC64_ATOMIC_H_
14#define _ASM_PPC64_ATOMIC_H_
15
16#include <asm/memory.h>
17
18typedef struct { volatile int counter; } atomic_t;
19
20#define ATOMIC_INIT(i) { (i) }
21
22#define atomic_read(v) ((v)->counter)
23#define atomic_set(v,i) (((v)->counter) = (i))
24
25static __inline__ void atomic_add(int a, atomic_t *v)
26{
27 int t;
28
29 __asm__ __volatile__(
30"1: lwarx %0,0,%3 # atomic_add\n\
31 add %0,%2,%0\n\
32 stwcx. %0,0,%3\n\
33 bne- 1b"
34 : "=&r" (t), "=m" (v->counter)
35 : "r" (a), "r" (&v->counter), "m" (v->counter)
36 : "cc");
37}
38
39static __inline__ int atomic_add_return(int a, atomic_t *v)
40{
41 int t;
42
43 __asm__ __volatile__(
44 EIEIO_ON_SMP
45"1: lwarx %0,0,%2 # atomic_add_return\n\
46 add %0,%1,%0\n\
47 stwcx. %0,0,%2\n\
48 bne- 1b"
49 ISYNC_ON_SMP
50 : "=&r" (t)
51 : "r" (a), "r" (&v->counter)
52 : "cc", "memory");
53
54 return t;
55}
56
57#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
58
59static __inline__ void atomic_sub(int a, atomic_t *v)
60{
61 int t;
62
63 __asm__ __volatile__(
64"1: lwarx %0,0,%3 # atomic_sub\n\
65 subf %0,%2,%0\n\
66 stwcx. %0,0,%3\n\
67 bne- 1b"
68 : "=&r" (t), "=m" (v->counter)
69 : "r" (a), "r" (&v->counter), "m" (v->counter)
70 : "cc");
71}
72
73static __inline__ int atomic_sub_return(int a, atomic_t *v)
74{
75 int t;
76
77 __asm__ __volatile__(
78 EIEIO_ON_SMP
79"1: lwarx %0,0,%2 # atomic_sub_return\n\
80 subf %0,%1,%0\n\
81 stwcx. %0,0,%2\n\
82 bne- 1b"
83 ISYNC_ON_SMP
84 : "=&r" (t)
85 : "r" (a), "r" (&v->counter)
86 : "cc", "memory");
87
88 return t;
89}
90
91static __inline__ void atomic_inc(atomic_t *v)
92{
93 int t;
94
95 __asm__ __volatile__(
96"1: lwarx %0,0,%2 # atomic_inc\n\
97 addic %0,%0,1\n\
98 stwcx. %0,0,%2\n\
99 bne- 1b"
100 : "=&r" (t), "=m" (v->counter)
101 : "r" (&v->counter), "m" (v->counter)
102 : "cc");
103}
104
105static __inline__ int atomic_inc_return(atomic_t *v)
106{
107 int t;
108
109 __asm__ __volatile__(
110 EIEIO_ON_SMP
111"1: lwarx %0,0,%1 # atomic_inc_return\n\
112 addic %0,%0,1\n\
113 stwcx. %0,0,%1\n\
114 bne- 1b"
115 ISYNC_ON_SMP
116 : "=&r" (t)
117 : "r" (&v->counter)
118 : "cc", "memory");
119
120 return t;
121}
122
123/*
124 * atomic_inc_and_test - increment and test
125 * @v: pointer of type atomic_t
126 *
127 * Atomically increments @v by 1
128 * and returns true if the result is zero, or false for all
129 * other cases.
130 */
131#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
132
133static __inline__ void atomic_dec(atomic_t *v)
134{
135 int t;
136
137 __asm__ __volatile__(
138"1: lwarx %0,0,%2 # atomic_dec\n\
139 addic %0,%0,-1\n\
140 stwcx. %0,0,%2\n\
141 bne- 1b"
142 : "=&r" (t), "=m" (v->counter)
143 : "r" (&v->counter), "m" (v->counter)
144 : "cc");
145}
146
147static __inline__ int atomic_dec_return(atomic_t *v)
148{
149 int t;
150
151 __asm__ __volatile__(
152 EIEIO_ON_SMP
153"1: lwarx %0,0,%1 # atomic_dec_return\n\
154 addic %0,%0,-1\n\
155 stwcx. %0,0,%1\n\
156 bne- 1b"
157 ISYNC_ON_SMP
158 : "=&r" (t)
159 : "r" (&v->counter)
160 : "cc", "memory");
161
162 return t;
163}
164
165#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
166#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
167
168/*
169 * Atomically test *v and decrement if it is greater than 0.
170 * The function returns the old value of *v minus 1.
171 */
172static __inline__ int atomic_dec_if_positive(atomic_t *v)
173{
174 int t;
175
176 __asm__ __volatile__(
177 EIEIO_ON_SMP
178"1: lwarx %0,0,%1 # atomic_dec_if_positive\n\
179 addic. %0,%0,-1\n\
180 blt- 2f\n\
181 stwcx. %0,0,%1\n\
182 bne- 1b"
183 ISYNC_ON_SMP
184 "\n\
1852:" : "=&r" (t)
186 : "r" (&v->counter)
187 : "cc", "memory");
188
189 return t;
190}
191
192#define smp_mb__before_atomic_dec() smp_mb()
193#define smp_mb__after_atomic_dec() smp_mb()
194#define smp_mb__before_atomic_inc() smp_mb()
195#define smp_mb__after_atomic_inc() smp_mb()
196
197#endif /* _ASM_PPC64_ATOMIC_H_ */