1 #ifndef _ASM_X86_ATOMIC_64_H
2 #define _ASM_X86_ATOMIC_64_H
4 #include <linux/types.h>
5 #include <asm/alternative.h>
6 #include <asm/cmpxchg.h>
9 * Atomic operations that C can't guarantee us. Useful for
10 * resource counting etc..
13 #define ATOMIC_INIT(i) { (i) }
16 * atomic_read - read atomic variable
17 * @v: pointer of type atomic_t
19 * Atomically reads the value of @v.
21 static inline int atomic_read(const atomic_t *v)
27 * atomic_set - set atomic variable
28 * @v: pointer of type atomic_t
31 * Atomically sets the value of @v to @i.
33 static inline void atomic_set(atomic_t *v, int i)
39 * atomic_add - add integer to atomic variable
40 * @i: integer value to add
41 * @v: pointer of type atomic_t
43 * Atomically adds @i to @v.
45 static inline void atomic_add(int i, atomic_t *v)
47 asm volatile(LOCK_PREFIX "addl %1,%0"
49 : "ir" (i), "m" (v->counter));
53 * atomic_sub - subtract the atomic variable
54 * @i: integer value to subtract
55 * @v: pointer of type atomic_t
57 * Atomically subtracts @i from @v.
59 static inline void atomic_sub(int i, atomic_t *v)
61 asm volatile(LOCK_PREFIX "subl %1,%0"
63 : "ir" (i), "m" (v->counter));
67 * atomic_sub_and_test - subtract value from variable and test result
68 * @i: integer value to subtract
69 * @v: pointer of type atomic_t
71 * Atomically subtracts @i from @v and returns
72 * true if the result is zero, or false for all
75 static inline int atomic_sub_and_test(int i, atomic_t *v)
79 asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
80 : "=m" (v->counter), "=qm" (c)
81 : "ir" (i), "m" (v->counter) : "memory");
86 * atomic_inc - increment atomic variable
87 * @v: pointer of type atomic_t
89 * Atomically increments @v by 1.
91 static inline void atomic_inc(atomic_t *v)
93 asm volatile(LOCK_PREFIX "incl %0"
99 * atomic_dec - decrement atomic variable
100 * @v: pointer of type atomic_t
102 * Atomically decrements @v by 1.
104 static inline void atomic_dec(atomic_t *v)
106 asm volatile(LOCK_PREFIX "decl %0"
112 * atomic_dec_and_test - decrement and test
113 * @v: pointer of type atomic_t
115 * Atomically decrements @v by 1 and
116 * returns true if the result is 0, or false for all other
119 static inline int atomic_dec_and_test(atomic_t *v)
123 asm volatile(LOCK_PREFIX "decl %0; sete %1"
124 : "=m" (v->counter), "=qm" (c)
125 : "m" (v->counter) : "memory");
130 * atomic_inc_and_test - increment and test
131 * @v: pointer of type atomic_t
133 * Atomically increments @v by 1
134 * and returns true if the result is zero, or false for all
137 static inline int atomic_inc_and_test(atomic_t *v)
141 asm volatile(LOCK_PREFIX "incl %0; sete %1"
142 : "=m" (v->counter), "=qm" (c)
143 : "m" (v->counter) : "memory");
148 * atomic_add_negative - add and test if negative
149 * @i: integer value to add
150 * @v: pointer of type atomic_t
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.
156 static inline int atomic_add_negative(int i, atomic_t *v)
160 asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
161 : "=m" (v->counter), "=qm" (c)
162 : "ir" (i), "m" (v->counter) : "memory");
167 * atomic_add_return - add and return
168 * @i: integer value to add
169 * @v: pointer of type atomic_t
171 * Atomically adds @i to @v and returns @i + @v
173 static inline int atomic_add_return(int i, atomic_t *v)
176 asm volatile(LOCK_PREFIX "xaddl %0, %1"
177 : "+r" (i), "+m" (v->counter)
182 static inline int atomic_sub_return(int i, atomic_t *v)
184 return atomic_add_return(-i, v);
187 #define atomic_inc_return(v) (atomic_add_return(1, v))
188 #define atomic_dec_return(v) (atomic_sub_return(1, v))
190 static inline long atomic_cmpxchg(atomic_t *v, int old, int new)
192 return cmpxchg(&v->counter, old, new);
195 static inline long atomic_xchg(atomic_t *v, int new)
197 return xchg(&v->counter, new);
201 * atomic_add_unless - add unless the number is a given value
202 * @v: pointer of type atomic_t
203 * @a: the amount to add to v...
204 * @u: ...unless v is equal to u.
206 * Atomically adds @a to @v, so long as it was not @u.
207 * Returns non-zero if @v was not @u, and zero otherwise.
209 static inline int atomic_add_unless(atomic_t *v, int a, int u)
214 if (unlikely(c == (u)))
216 old = atomic_cmpxchg((v), c, c + (a));
217 if (likely(old == c))
224 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
227 * atomic_inc_short - increment of a short integer
228 * @v: pointer to type int
230 * Atomically adds 1 to @v
231 * Returns the new value of @u
233 static inline short int atomic_inc_short(short int *v)
235 asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
240 * atomic_or_long - OR of two long integers
241 * @v1: pointer to type unsigned long
242 * @v2: pointer to type unsigned long
244 * Atomically ORs @v1 and @v2
245 * Returns the result of the OR
247 static inline void atomic_or_long(unsigned long *v1, unsigned long v2)
249 asm(LOCK_PREFIX "orq %1, %0" : "+m" (*v1) : "r" (v2));
252 /* These are x86-specific, used by some header files */
253 #define atomic_clear_mask(mask, addr) \
254 asm volatile(LOCK_PREFIX "andl %0,%1" \
255 : : "r" (~(mask)), "m" (*(addr)) : "memory")
257 #define atomic_set_mask(mask, addr) \
258 asm volatile(LOCK_PREFIX "orl %0,%1" \
259 : : "r" ((unsigned)(mask)), "m" (*(addr)) \
262 /* Atomic operations are already serializing on x86 */
263 #define smp_mb__before_atomic_dec() barrier()
264 #define smp_mb__after_atomic_dec() barrier()
265 #define smp_mb__before_atomic_inc() barrier()
266 #define smp_mb__after_atomic_inc() barrier()
268 #include <asm/atomic64_64.h>
269 #include <asm-generic/atomic-long.h>
270 #endif /* _ASM_X86_ATOMIC_64_H */