1 #ifndef _ASM_X86_ATOMIC_H
2 #define _ASM_X86_ATOMIC_H
3
4 #include <linux/bitops.h>
5 #include <linux/compiler.h>
6 #include <linux/types.h>
7 #include <asm/processor.h>
8
9 typedef struct { volatile int counter; } atomic_t;
10
11 /*
12 * Atomic operations that C can't guarantee us. Useful for
13 * resource counting etc..
14 */
15
16 #define ATOMIC_INIT(i) { (i) }
17
18 /**
19 * atomic_read - read atomic variable
20 * @v: pointer of type atomic_t
21 *
22 * Atomically reads the value of @v.
23 */
atomic_read(const atomic_t * v)24 static inline int atomic_read(const atomic_t *v)
25 {
26 return READ_ONCE((v)->counter);
27 }
28
29 /**
30 * atomic_set - set atomic variable
31 * @v: pointer of type atomic_t
32 * @i: required value
33 *
34 * Atomically sets the value of @v to @i.
35 */
atomic_set(atomic_t * v,int i)36 static inline void atomic_set(atomic_t *v, int i)
37 {
38 v->counter = i;
39 }
40
41 /**
42 * atomic_add - add integer to atomic variable
43 * @i: integer value to add
44 * @v: pointer of type atomic_t
45 *
46 * Atomically adds @i to @v.
47 */
atomic_add(int i,atomic_t * v)48 static inline void atomic_add(int i, atomic_t *v)
49 {
50 asm volatile(LOCK_PREFIX "addl %1,%0"
51 : "+m" (v->counter)
52 : "ir" (i));
53 }
54
55 /**
56 * atomic_sub - subtract integer from atomic variable
57 * @i: integer value to subtract
58 * @v: pointer of type atomic_t
59 *
60 * Atomically subtracts @i from @v.
61 */
atomic_sub(int i,atomic_t * v)62 static inline void atomic_sub(int i, atomic_t *v)
63 {
64 asm volatile(LOCK_PREFIX "subl %1,%0"
65 : "+m" (v->counter)
66 : "ir" (i));
67 }
68
69 /**
70 * atomic_inc - increment atomic variable
71 * @v: pointer of type atomic_t
72 *
73 * Atomically increments @v by 1.
74 */
atomic_inc(atomic_t * v)75 static inline void atomic_inc(atomic_t *v)
76 {
77 asm volatile(LOCK_PREFIX "incl %0"
78 : "+m" (v->counter));
79 }
80
81 /**
82 * atomic_dec - decrement atomic variable
83 * @v: pointer of type atomic_t
84 *
85 * Atomically decrements @v by 1.
86 */
atomic_dec(atomic_t * v)87 static inline void atomic_dec(atomic_t *v)
88 {
89 asm volatile(LOCK_PREFIX "decl %0"
90 : "+m" (v->counter));
91 }
92
93 /**
94 * atomic_inc_short - increment of a short integer
95 * @v: pointer to type int
96 *
97 * Atomically adds 1 to @v
98 * Returns the new value of @u
99 */
atomic_inc_short(short int * v)100 static inline short int atomic_inc_short(short int *v)
101 {
102 asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v));
103 return *v;
104 }
105
106 /* These are x86-specific, used by some header files */
107 #define atomic_clear_mask(mask, addr) \
108 asm volatile(LOCK_PREFIX "andl %0,%1" \
109 : : "r" (~(mask)), "m" (*(addr)) : "memory")
110
111 #define atomic_set_mask(mask, addr) \
112 asm volatile(LOCK_PREFIX "orl %0,%1" \
113 : : "r" ((unsigned)(mask)), "m" (*(addr)) \
114 : "memory")
115
116 #endif /* _ASM_X86_ATOMIC_H */
117