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10b663ae CM |
1 | /* |
2 | * Based on arch/arm/include/asm/cmpxchg.h | |
3 | * | |
4 | * Copyright (C) 2012 ARM Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
17 | */ | |
18 | #ifndef __ASM_CMPXCHG_H | |
19 | #define __ASM_CMPXCHG_H | |
20 | ||
21 | #include <linux/bug.h> | |
22 | ||
23 | #include <asm/barrier.h> | |
24 | ||
25 | static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) | |
26 | { | |
27 | unsigned long ret, tmp; | |
28 | ||
29 | switch (size) { | |
30 | case 1: | |
31 | asm volatile("// __xchg1\n" | |
32 | "1: ldaxrb %w0, [%3]\n" | |
33 | " stlxrb %w1, %w2, [%3]\n" | |
34 | " cbnz %w1, 1b\n" | |
35 | : "=&r" (ret), "=&r" (tmp) | |
36 | : "r" (x), "r" (ptr) | |
37 | : "memory", "cc"); | |
38 | break; | |
39 | case 2: | |
40 | asm volatile("// __xchg2\n" | |
41 | "1: ldaxrh %w0, [%3]\n" | |
42 | " stlxrh %w1, %w2, [%3]\n" | |
43 | " cbnz %w1, 1b\n" | |
44 | : "=&r" (ret), "=&r" (tmp) | |
45 | : "r" (x), "r" (ptr) | |
46 | : "memory", "cc"); | |
47 | break; | |
48 | case 4: | |
49 | asm volatile("// __xchg4\n" | |
50 | "1: ldaxr %w0, [%3]\n" | |
51 | " stlxr %w1, %w2, [%3]\n" | |
52 | " cbnz %w1, 1b\n" | |
53 | : "=&r" (ret), "=&r" (tmp) | |
54 | : "r" (x), "r" (ptr) | |
55 | : "memory", "cc"); | |
56 | break; | |
57 | case 8: | |
58 | asm volatile("// __xchg8\n" | |
59 | "1: ldaxr %0, [%3]\n" | |
60 | " stlxr %w1, %2, [%3]\n" | |
61 | " cbnz %w1, 1b\n" | |
62 | : "=&r" (ret), "=&r" (tmp) | |
63 | : "r" (x), "r" (ptr) | |
64 | : "memory", "cc"); | |
65 | break; | |
66 | default: | |
67 | BUILD_BUG(); | |
68 | } | |
69 | ||
70 | return ret; | |
71 | } | |
72 | ||
73 | #define xchg(ptr,x) \ | |
74 | ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) | |
75 | ||
76 | static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, | |
77 | unsigned long new, int size) | |
78 | { | |
79 | unsigned long oldval = 0, res; | |
80 | ||
81 | switch (size) { | |
82 | case 1: | |
83 | do { | |
84 | asm volatile("// __cmpxchg1\n" | |
85 | " ldxrb %w1, [%2]\n" | |
86 | " mov %w0, #0\n" | |
87 | " cmp %w1, %w3\n" | |
88 | " b.ne 1f\n" | |
89 | " stxrb %w0, %w4, [%2]\n" | |
90 | "1:\n" | |
91 | : "=&r" (res), "=&r" (oldval) | |
92 | : "r" (ptr), "Ir" (old), "r" (new) | |
93 | : "cc"); | |
94 | } while (res); | |
95 | break; | |
96 | ||
97 | case 2: | |
98 | do { | |
99 | asm volatile("// __cmpxchg2\n" | |
100 | " ldxrh %w1, [%2]\n" | |
101 | " mov %w0, #0\n" | |
102 | " cmp %w1, %w3\n" | |
103 | " b.ne 1f\n" | |
104 | " stxrh %w0, %w4, [%2]\n" | |
105 | "1:\n" | |
106 | : "=&r" (res), "=&r" (oldval) | |
107 | : "r" (ptr), "Ir" (old), "r" (new) | |
108 | : "memory", "cc"); | |
109 | } while (res); | |
110 | break; | |
111 | ||
112 | case 4: | |
113 | do { | |
114 | asm volatile("// __cmpxchg4\n" | |
115 | " ldxr %w1, [%2]\n" | |
116 | " mov %w0, #0\n" | |
117 | " cmp %w1, %w3\n" | |
118 | " b.ne 1f\n" | |
119 | " stxr %w0, %w4, [%2]\n" | |
120 | "1:\n" | |
121 | : "=&r" (res), "=&r" (oldval) | |
122 | : "r" (ptr), "Ir" (old), "r" (new) | |
123 | : "cc"); | |
124 | } while (res); | |
125 | break; | |
126 | ||
127 | case 8: | |
128 | do { | |
129 | asm volatile("// __cmpxchg8\n" | |
130 | " ldxr %1, [%2]\n" | |
131 | " mov %w0, #0\n" | |
132 | " cmp %1, %3\n" | |
133 | " b.ne 1f\n" | |
134 | " stxr %w0, %4, [%2]\n" | |
135 | "1:\n" | |
136 | : "=&r" (res), "=&r" (oldval) | |
137 | : "r" (ptr), "Ir" (old), "r" (new) | |
138 | : "cc"); | |
139 | } while (res); | |
140 | break; | |
141 | ||
142 | default: | |
143 | BUILD_BUG(); | |
144 | } | |
145 | ||
146 | return oldval; | |
147 | } | |
148 | ||
149 | static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old, | |
150 | unsigned long new, int size) | |
151 | { | |
152 | unsigned long ret; | |
153 | ||
154 | smp_mb(); | |
155 | ret = __cmpxchg(ptr, old, new, size); | |
156 | smp_mb(); | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | #define cmpxchg(ptr,o,n) \ | |
162 | ((__typeof__(*(ptr)))__cmpxchg_mb((ptr), \ | |
163 | (unsigned long)(o), \ | |
164 | (unsigned long)(n), \ | |
165 | sizeof(*(ptr)))) | |
166 | ||
167 | #define cmpxchg_local(ptr,o,n) \ | |
168 | ((__typeof__(*(ptr)))__cmpxchg((ptr), \ | |
169 | (unsigned long)(o), \ | |
170 | (unsigned long)(n), \ | |
171 | sizeof(*(ptr)))) | |
172 | ||
173 | #endif /* __ASM_CMPXCHG_H */ |