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Linux 3.11-rc3
[cris-mirror.git] / arch / x86 / include / asm / cmpxchg.h
blobd47786acb0169d0c2e87e830384ecac579cbc18c
1 #ifndef ASM_X86_CMPXCHG_H
2 #define ASM_X86_CMPXCHG_H
3
4 #include <linux/compiler.h>
5 #include <asm/alternative.h> /* Provides LOCK_PREFIX */
6
7 /*
8 * Non-existant functions to indicate usage errors at link time
9 * (or compile-time if the compiler implements __compiletime_error().
10 */
11 extern void __xchg_wrong_size(void)
12 __compiletime_error("Bad argument size for xchg");
13 extern void __cmpxchg_wrong_size(void)
14 __compiletime_error("Bad argument size for cmpxchg");
15 extern void __xadd_wrong_size(void)
16 __compiletime_error("Bad argument size for xadd");
17 extern void __add_wrong_size(void)
18 __compiletime_error("Bad argument size for add");
19
20 /*
21 * Constants for operation sizes. On 32-bit, the 64-bit size it set to
22 * -1 because sizeof will never return -1, thereby making those switch
23 * case statements guaranteeed dead code which the compiler will
24 * eliminate, and allowing the "missing symbol in the default case" to
25 * indicate a usage error.
26 */
27 #define __X86_CASE_B 1
28 #define __X86_CASE_W 2
29 #define __X86_CASE_L 4
30 #ifdef CONFIG_64BIT
31 #define __X86_CASE_Q 8
32 #else
33 #define __X86_CASE_Q -1 /* sizeof will never return -1 */
34 #endif
35
36 /*
37 * An exchange-type operation, which takes a value and a pointer, and
38 * returns the old value.
39 */
40 #define __xchg_op(ptr, arg, op, lock) \
41 ({ \
42 __typeof__ (*(ptr)) __ret = (arg); \
43 switch (sizeof(*(ptr))) { \
44 case __X86_CASE_B: \
45 asm volatile (lock #op "b %b0, %1\n" \
46 : "+q" (__ret), "+m" (*(ptr)) \
47 : : "memory", "cc"); \
48 break; \
49 case __X86_CASE_W: \
50 asm volatile (lock #op "w %w0, %1\n" \
51 : "+r" (__ret), "+m" (*(ptr)) \
52 : : "memory", "cc"); \
53 break; \
54 case __X86_CASE_L: \
55 asm volatile (lock #op "l %0, %1\n" \
56 : "+r" (__ret), "+m" (*(ptr)) \
57 : : "memory", "cc"); \
58 break; \
59 case __X86_CASE_Q: \
60 asm volatile (lock #op "q %q0, %1\n" \
61 : "+r" (__ret), "+m" (*(ptr)) \
62 : : "memory", "cc"); \
63 break; \
64 default: \
65 __ ## op ## _wrong_size(); \
66 } \
67 __ret; \
68 })
69
70 /*
71 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
72 * Since this is generally used to protect other memory information, we
73 * use "asm volatile" and "memory" clobbers to prevent gcc from moving
74 * information around.
75 */
76 #define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "")
77
78 /*
79 * Atomic compare and exchange. Compare OLD with MEM, if identical,
80 * store NEW in MEM. Return the initial value in MEM. Success is
81 * indicated by comparing RETURN with OLD.
82 */
83 #define __raw_cmpxchg(ptr, old, new, size, lock) \
84 ({ \
85 __typeof__(*(ptr)) __ret; \
86 __typeof__(*(ptr)) __old = (old); \
87 __typeof__(*(ptr)) __new = (new); \
88 switch (size) { \
89 case __X86_CASE_B: \
90 { \
91 volatile u8 *__ptr = (volatile u8 *)(ptr); \
92 asm volatile(lock "cmpxchgb %2,%1" \
93 : "=a" (__ret), "+m" (*__ptr) \
94 : "q" (__new), "0" (__old) \
95 : "memory"); \
96 break; \
97 } \
98 case __X86_CASE_W: \
99 { \
100 volatile u16 *__ptr = (volatile u16 *)(ptr); \
101 asm volatile(lock "cmpxchgw %2,%1" \
102 : "=a" (__ret), "+m" (*__ptr) \
103 : "r" (__new), "0" (__old) \
104 : "memory"); \
105 break; \
106 } \
107 case __X86_CASE_L: \
108 { \
109 volatile u32 *__ptr = (volatile u32 *)(ptr); \
110 asm volatile(lock "cmpxchgl %2,%1" \
111 : "=a" (__ret), "+m" (*__ptr) \
112 : "r" (__new), "0" (__old) \
113 : "memory"); \
114 break; \
115 } \
116 case __X86_CASE_Q: \
117 { \
118 volatile u64 *__ptr = (volatile u64 *)(ptr); \
119 asm volatile(lock "cmpxchgq %2,%1" \
120 : "=a" (__ret), "+m" (*__ptr) \
121 : "r" (__new), "0" (__old) \
122 : "memory"); \
123 break; \
124 } \
125 default: \
126 __cmpxchg_wrong_size(); \
127 } \
128 __ret; \
129 })
130
131 #define __cmpxchg(ptr, old, new, size) \
132 __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
133
134 #define __sync_cmpxchg(ptr, old, new, size) \
135 __raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
136
137 #define __cmpxchg_local(ptr, old, new, size) \
138 __raw_cmpxchg((ptr), (old), (new), (size), "")
139
140 #ifdef CONFIG_X86_32
141 # include <asm/cmpxchg_32.h>
142 #else
143 # include <asm/cmpxchg_64.h>
144 #endif
145
146 #ifdef __HAVE_ARCH_CMPXCHG
147 #define cmpxchg(ptr, old, new) \
148 __cmpxchg(ptr, old, new, sizeof(*(ptr)))
149
150 #define sync_cmpxchg(ptr, old, new) \
151 __sync_cmpxchg(ptr, old, new, sizeof(*(ptr)))
152
153 #define cmpxchg_local(ptr, old, new) \
154 __cmpxchg_local(ptr, old, new, sizeof(*(ptr)))
155 #endif
156
157 /*
158 * xadd() adds "inc" to "*ptr" and atomically returns the previous
159 * value of "*ptr".
160 *
161 * xadd() is locked when multiple CPUs are online
162 * xadd_sync() is always locked
163 * xadd_local() is never locked
164 */
165 #define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock)
166 #define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX)
167 #define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ")
168 #define xadd_local(ptr, inc) __xadd((ptr), (inc), "")
169
170 #define __add(ptr, inc, lock) \
171 ({ \
172 __typeof__ (*(ptr)) __ret = (inc); \
173 switch (sizeof(*(ptr))) { \
174 case __X86_CASE_B: \
175 asm volatile (lock "addb %b1, %0\n" \
176 : "+m" (*(ptr)) : "qi" (inc) \
177 : "memory", "cc"); \
178 break; \
179 case __X86_CASE_W: \
180 asm volatile (lock "addw %w1, %0\n" \
181 : "+m" (*(ptr)) : "ri" (inc) \
182 : "memory", "cc"); \
183 break; \
184 case __X86_CASE_L: \
185 asm volatile (lock "addl %1, %0\n" \
186 : "+m" (*(ptr)) : "ri" (inc) \
187 : "memory", "cc"); \
188 break; \
189 case __X86_CASE_Q: \
190 asm volatile (lock "addq %1, %0\n" \
191 : "+m" (*(ptr)) : "ri" (inc) \
192 : "memory", "cc"); \
193 break; \
194 default: \
195 __add_wrong_size(); \
196 } \
197 __ret; \
198 })
199
200 /*
201 * add_*() adds "inc" to "*ptr"
202 *
203 * __add() takes a lock prefix
204 * add_smp() is locked when multiple CPUs are online
205 * add_sync() is always locked
206 */
207 #define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX)
208 #define add_sync(ptr, inc) __add((ptr), (inc), "lock; ")
209
210 #define __cmpxchg_double(pfx, p1, p2, o1, o2, n1, n2) \
211 ({ \
212 bool __ret; \
213 __typeof__(*(p1)) __old1 = (o1), __new1 = (n1); \
214 __typeof__(*(p2)) __old2 = (o2), __new2 = (n2); \
215 BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long)); \
216 BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long)); \
217 VM_BUG_ON((unsigned long)(p1) % (2 * sizeof(long))); \
218 VM_BUG_ON((unsigned long)((p1) + 1) != (unsigned long)(p2)); \
219 asm volatile(pfx "cmpxchg%c4b %2; sete %0" \
220 : "=a" (__ret), "+d" (__old2), \
221 "+m" (*(p1)), "+m" (*(p2)) \
222 : "i" (2 * sizeof(long)), "a" (__old1), \
223 "b" (__new1), "c" (__new2)); \
224 __ret; \
225 })
226
227 #define cmpxchg_double(p1, p2, o1, o2, n1, n2) \
228 __cmpxchg_double(LOCK_PREFIX, p1, p2, o1, o2, n1, n2)
229
230 #define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \
231 __cmpxchg_double(, p1, p2, o1, o2, n1, n2)
232
233 #endif /* ASM_X86_CMPXCHG_H */
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