1 #ifndef _ASM_X86_LOCAL_H
2 #define _ASM_X86_LOCAL_H
3
4 #include <linux/percpu.h>
5
6 #include <linux/atomic.h>
7 #include <asm/asm.h>
8
9 typedef struct {
10 atomic_long_t a;
11 } local_t;
12
13 #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
14
15 #define local_read(l) atomic_long_read(&(l)->a)
16 #define local_set(l, i) atomic_long_set(&(l)->a, (i))
17
local_inc(local_t * l)18 static inline void local_inc(local_t *l)
19 {
20 asm volatile(_ASM_INC "%0"
21 : "+m" (l->a.counter));
22 }
23
local_dec(local_t * l)24 static inline void local_dec(local_t *l)
25 {
26 asm volatile(_ASM_DEC "%0"
27 : "+m" (l->a.counter));
28 }
29
local_add(long i,local_t * l)30 static inline void local_add(long i, local_t *l)
31 {
32 asm volatile(_ASM_ADD "%1,%0"
33 : "+m" (l->a.counter)
34 : "ir" (i));
35 }
36
local_sub(long i,local_t * l)37 static inline void local_sub(long i, local_t *l)
38 {
39 asm volatile(_ASM_SUB "%1,%0"
40 : "+m" (l->a.counter)
41 : "ir" (i));
42 }
43
44 /**
45 * local_sub_and_test - subtract value from variable and test result
46 * @i: integer value to subtract
47 * @l: pointer to type local_t
48 *
49 * Atomically subtracts @i from @l and returns
50 * true if the result is zero, or false for all
51 * other cases.
52 */
local_sub_and_test(long i,local_t * l)53 static inline int local_sub_and_test(long i, local_t *l)
54 {
55 GEN_BINARY_RMWcc(_ASM_SUB, l->a.counter, "er", i, "%0", e);
56 }
57
58 /**
59 * local_dec_and_test - decrement and test
60 * @l: pointer to type local_t
61 *
62 * Atomically decrements @l by 1 and
63 * returns true if the result is 0, or false for all other
64 * cases.
65 */
local_dec_and_test(local_t * l)66 static inline int local_dec_and_test(local_t *l)
67 {
68 GEN_UNARY_RMWcc(_ASM_DEC, l->a.counter, "%0", e);
69 }
70
71 /**
72 * local_inc_and_test - increment and test
73 * @l: pointer to type local_t
74 *
75 * Atomically increments @l by 1
76 * and returns true if the result is zero, or false for all
77 * other cases.
78 */
local_inc_and_test(local_t * l)79 static inline int local_inc_and_test(local_t *l)
80 {
81 GEN_UNARY_RMWcc(_ASM_INC, l->a.counter, "%0", e);
82 }
83
84 /**
85 * local_add_negative - add and test if negative
86 * @i: integer value to add
87 * @l: pointer to type local_t
88 *
89 * Atomically adds @i to @l and returns true
90 * if the result is negative, or false when
91 * result is greater than or equal to zero.
92 */
local_add_negative(long i,local_t * l)93 static inline int local_add_negative(long i, local_t *l)
94 {
95 GEN_BINARY_RMWcc(_ASM_ADD, l->a.counter, "er", i, "%0", s);
96 }
97
98 /**
99 * local_add_return - add and return
100 * @i: integer value to add
101 * @l: pointer to type local_t
102 *
103 * Atomically adds @i to @l and returns @i + @l
104 */
local_add_return(long i,local_t * l)105 static inline long local_add_return(long i, local_t *l)
106 {
107 long __i = i;
108 asm volatile(_ASM_XADD "%0, %1;"
109 : "+r" (i), "+m" (l->a.counter)
110 : : "memory");
111 return i + __i;
112 }
113
local_sub_return(long i,local_t * l)114 static inline long local_sub_return(long i, local_t *l)
115 {
116 return local_add_return(-i, l);
117 }
118
119 #define local_inc_return(l) (local_add_return(1, l))
120 #define local_dec_return(l) (local_sub_return(1, l))
121
122 #define local_cmpxchg(l, o, n) \
123 (cmpxchg_local(&((l)->a.counter), (o), (n)))
124 /* Always has a lock prefix */
125 #define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
126
127 /**
128 * local_add_unless - add unless the number is a given value
129 * @l: pointer of type local_t
130 * @a: the amount to add to l...
131 * @u: ...unless l is equal to u.
132 *
133 * Atomically adds @a to @l, so long as it was not @u.
134 * Returns non-zero if @l was not @u, and zero otherwise.
135 */
136 #define local_add_unless(l, a, u) \
137 ({ \
138 long c, old; \
139 c = local_read((l)); \
140 for (;;) { \
141 if (unlikely(c == (u))) \
142 break; \
143 old = local_cmpxchg((l), c, c + (a)); \
144 if (likely(old == c)) \
145 break; \
146 c = old; \
147 } \
148 c != (u); \
149 })
150 #define local_inc_not_zero(l) local_add_unless((l), 1, 0)
151
152 /* On x86_32, these are no better than the atomic variants.
153 * On x86-64 these are better than the atomic variants on SMP kernels
154 * because they dont use a lock prefix.
155 */
156 #define __local_inc(l) local_inc(l)
157 #define __local_dec(l) local_dec(l)
158 #define __local_add(i, l) local_add((i), (l))
159 #define __local_sub(i, l) local_sub((i), (l))
160
161 #endif /* _ASM_X86_LOCAL_H */
162