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1 | #ifndef _ASM_X86_ATOMIC_H |
2 | #define _ASM_X86_ATOMIC_H | |
3 | ||
4 | #include <linux/compiler.h> | |
5 | #include <linux/types.h> | |
6 | #include <asm/processor.h> | |
7 | #include <asm/alternative.h> | |
8 | #include <asm/cmpxchg.h> | |
9 | ||
10 | /* | |
11 | * Atomic operations that C can't guarantee us. Useful for | |
12 | * resource counting etc.. | |
13 | */ | |
14 | ||
15 | #define ATOMIC_INIT(i) { (i) } | |
16 | ||
17 | /** | |
18 | * atomic_read - read atomic variable | |
19 | * @v: pointer of type atomic_t | |
20 | * | |
21 | * Atomically reads the value of @v. | |
22 | */ | |
23 | static inline int atomic_read(const atomic_t *v) | |
24 | { | |
f3d46f9d | 25 | return (*(volatile int *)&(v)->counter); |
5abbbbf0 BG |
26 | } |
27 | ||
28 | /** | |
29 | * atomic_set - set atomic variable | |
30 | * @v: pointer of type atomic_t | |
31 | * @i: required value | |
32 | * | |
33 | * Atomically sets the value of @v to @i. | |
34 | */ | |
35 | static inline void atomic_set(atomic_t *v, int i) | |
36 | { | |
37 | v->counter = i; | |
38 | } | |
39 | ||
40 | /** | |
41 | * atomic_add - add integer to atomic variable | |
42 | * @i: integer value to add | |
43 | * @v: pointer of type atomic_t | |
44 | * | |
45 | * Atomically adds @i to @v. | |
46 | */ | |
47 | static inline void atomic_add(int i, atomic_t *v) | |
48 | { | |
49 | asm volatile(LOCK_PREFIX "addl %1,%0" | |
50 | : "+m" (v->counter) | |
51 | : "ir" (i)); | |
52 | } | |
53 | ||
54 | /** | |
55 | * atomic_sub - subtract integer from atomic variable | |
56 | * @i: integer value to subtract | |
57 | * @v: pointer of type atomic_t | |
58 | * | |
59 | * Atomically subtracts @i from @v. | |
60 | */ | |
61 | static inline void atomic_sub(int i, atomic_t *v) | |
62 | { | |
63 | asm volatile(LOCK_PREFIX "subl %1,%0" | |
64 | : "+m" (v->counter) | |
65 | : "ir" (i)); | |
66 | } | |
67 | ||
68 | /** | |
69 | * atomic_sub_and_test - subtract value from variable and test result | |
70 | * @i: integer value to subtract | |
71 | * @v: pointer of type atomic_t | |
72 | * | |
73 | * Atomically subtracts @i from @v and returns | |
74 | * true if the result is zero, or false for all | |
75 | * other cases. | |
76 | */ | |
77 | static inline int atomic_sub_and_test(int i, atomic_t *v) | |
78 | { | |
79 | unsigned char c; | |
80 | ||
81 | asm volatile(LOCK_PREFIX "subl %2,%0; sete %1" | |
82 | : "+m" (v->counter), "=qm" (c) | |
83 | : "ir" (i) : "memory"); | |
84 | return c; | |
85 | } | |
86 | ||
87 | /** | |
88 | * atomic_inc - increment atomic variable | |
89 | * @v: pointer of type atomic_t | |
90 | * | |
91 | * Atomically increments @v by 1. | |
92 | */ | |
93 | static inline void atomic_inc(atomic_t *v) | |
94 | { | |
95 | asm volatile(LOCK_PREFIX "incl %0" | |
96 | : "+m" (v->counter)); | |
97 | } | |
98 | ||
99 | /** | |
100 | * atomic_dec - decrement atomic variable | |
101 | * @v: pointer of type atomic_t | |
102 | * | |
103 | * Atomically decrements @v by 1. | |
104 | */ | |
105 | static inline void atomic_dec(atomic_t *v) | |
106 | { | |
107 | asm volatile(LOCK_PREFIX "decl %0" | |
108 | : "+m" (v->counter)); | |
109 | } | |
110 | ||
111 | /** | |
112 | * atomic_dec_and_test - decrement and test | |
113 | * @v: pointer of type atomic_t | |
114 | * | |
115 | * Atomically decrements @v by 1 and | |
116 | * returns true if the result is 0, or false for all other | |
117 | * cases. | |
118 | */ | |
119 | static inline int atomic_dec_and_test(atomic_t *v) | |
120 | { | |
121 | unsigned char c; | |
122 | ||
123 | asm volatile(LOCK_PREFIX "decl %0; sete %1" | |
124 | : "+m" (v->counter), "=qm" (c) | |
125 | : : "memory"); | |
126 | return c != 0; | |
127 | } | |
128 | ||
129 | /** | |
130 | * atomic_inc_and_test - increment and test | |
131 | * @v: pointer of type atomic_t | |
132 | * | |
133 | * Atomically increments @v by 1 | |
134 | * and returns true if the result is zero, or false for all | |
135 | * other cases. | |
136 | */ | |
137 | static inline int atomic_inc_and_test(atomic_t *v) | |
138 | { | |
139 | unsigned char c; | |
140 | ||
141 | asm volatile(LOCK_PREFIX "incl %0; sete %1" | |
142 | : "+m" (v->counter), "=qm" (c) | |
143 | : : "memory"); | |
144 | return c != 0; | |
145 | } | |
146 | ||
147 | /** | |
148 | * atomic_add_negative - add and test if negative | |
149 | * @i: integer value to add | |
150 | * @v: pointer of type atomic_t | |
151 | * | |
152 | * Atomically adds @i to @v and returns true | |
153 | * if the result is negative, or false when | |
154 | * result is greater than or equal to zero. | |
155 | */ | |
156 | static inline int atomic_add_negative(int i, atomic_t *v) | |
157 | { | |
158 | unsigned char c; | |
159 | ||
160 | asm volatile(LOCK_PREFIX "addl %2,%0; sets %1" | |
161 | : "+m" (v->counter), "=qm" (c) | |
162 | : "ir" (i) : "memory"); | |
163 | return c; | |
164 | } | |
165 | ||
166 | /** | |
167 | * atomic_add_return - add integer and return | |
168 | * @i: integer value to add | |
169 | * @v: pointer of type atomic_t | |
170 | * | |
171 | * Atomically adds @i to @v and returns @i + @v | |
172 | */ | |
173 | static inline int atomic_add_return(int i, atomic_t *v) | |
174 | { | |
8b8bc2f7 | 175 | return i + xadd(&v->counter, i); |
5abbbbf0 BG |
176 | } |
177 | ||
178 | /** | |
179 | * atomic_sub_return - subtract integer and return | |
180 | * @v: pointer of type atomic_t | |
181 | * @i: integer value to subtract | |
182 | * | |
183 | * Atomically subtracts @i from @v and returns @v - @i | |
184 | */ | |
185 | static inline int atomic_sub_return(int i, atomic_t *v) | |
186 | { | |
187 | return atomic_add_return(-i, v); | |
188 | } | |
189 | ||
190 | #define atomic_inc_return(v) (atomic_add_return(1, v)) | |
191 | #define atomic_dec_return(v) (atomic_sub_return(1, v)) | |
192 | ||
193 | static inline int atomic_cmpxchg(atomic_t *v, int old, int new) | |
194 | { | |
195 | return cmpxchg(&v->counter, old, new); | |
196 | } | |
197 | ||
198 | static inline int atomic_xchg(atomic_t *v, int new) | |
199 | { | |
200 | return xchg(&v->counter, new); | |
201 | } | |
202 | ||
203 | /** | |
f24219b4 | 204 | * __atomic_add_unless - add unless the number is already a given value |
5abbbbf0 BG |
205 | * @v: pointer of type atomic_t |
206 | * @a: the amount to add to v... | |
207 | * @u: ...unless v is equal to u. | |
208 | * | |
209 | * Atomically adds @a to @v, so long as @v was not already @u. | |
f24219b4 | 210 | * Returns the old value of @v. |
5abbbbf0 | 211 | */ |
f24219b4 | 212 | static inline int __atomic_add_unless(atomic_t *v, int a, int u) |
5abbbbf0 BG |
213 | { |
214 | int c, old; | |
215 | c = atomic_read(v); | |
216 | for (;;) { | |
217 | if (unlikely(c == (u))) | |
218 | break; | |
219 | old = atomic_cmpxchg((v), c, c + (a)); | |
220 | if (likely(old == c)) | |
221 | break; | |
222 | c = old; | |
223 | } | |
f24219b4 | 224 | return c; |
5abbbbf0 BG |
225 | } |
226 | ||
5abbbbf0 BG |
227 | /** |
228 | * atomic_inc_short - increment of a short integer | |
229 | * @v: pointer to type int | |
230 | * | |
231 | * Atomically adds 1 to @v | |
232 | * Returns the new value of @u | |
233 | */ | |
234 | static inline short int atomic_inc_short(short int *v) | |
235 | { | |
236 | asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v)); | |
237 | return *v; | |
238 | } | |
239 | ||
240 | #ifdef CONFIG_X86_64 | |
241 | /** | |
242 | * atomic_or_long - OR of two long integers | |
243 | * @v1: pointer to type unsigned long | |
244 | * @v2: pointer to type unsigned long | |
245 | * | |
246 | * Atomically ORs @v1 and @v2 | |
247 | * Returns the result of the OR | |
248 | */ | |
249 | static inline void atomic_or_long(unsigned long *v1, unsigned long v2) | |
250 | { | |
251 | asm(LOCK_PREFIX "orq %1, %0" : "+m" (*v1) : "r" (v2)); | |
252 | } | |
253 | #endif | |
254 | ||
255 | /* These are x86-specific, used by some header files */ | |
256 | #define atomic_clear_mask(mask, addr) \ | |
257 | asm volatile(LOCK_PREFIX "andl %0,%1" \ | |
258 | : : "r" (~(mask)), "m" (*(addr)) : "memory") | |
259 | ||
260 | #define atomic_set_mask(mask, addr) \ | |
261 | asm volatile(LOCK_PREFIX "orl %0,%1" \ | |
262 | : : "r" ((unsigned)(mask)), "m" (*(addr)) \ | |
263 | : "memory") | |
264 | ||
265 | /* Atomic operations are already serializing on x86 */ | |
266 | #define smp_mb__before_atomic_dec() barrier() | |
267 | #define smp_mb__after_atomic_dec() barrier() | |
268 | #define smp_mb__before_atomic_inc() barrier() | |
269 | #define smp_mb__after_atomic_inc() barrier() | |
270 | ||
96a388de | 271 | #ifdef CONFIG_X86_32 |
a1ce3928 | 272 | # include <asm/atomic64_32.h> |
96a388de | 273 | #else |
a1ce3928 | 274 | # include <asm/atomic64_64.h> |
96a388de | 275 | #endif |
5abbbbf0 | 276 | |
5abbbbf0 | 277 | #endif /* _ASM_X86_ATOMIC_H */ |