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H. Peter Anvin1965aae2008-10-22 22:26:29 -07001#ifndef _ASM_X86_LOCAL_H
2#define _ASM_X86_LOCAL_H
Harvey Harrison5638f992008-01-30 13:31:26 +01003
4#include <linux/percpu.h>
5
6#include <asm/system.h>
7#include <asm/atomic.h>
8#include <asm/asm.h>
9
Harvey Harrison01c57fb2008-01-30 13:31:26 +010010typedef struct {
Harvey Harrison5638f992008-01-30 13:31:26 +010011 atomic_long_t a;
12} local_t;
13
14#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
15
16#define local_read(l) atomic_long_read(&(l)->a)
Harvey Harrison01c57fb2008-01-30 13:31:26 +010017#define local_set(l, i) atomic_long_set(&(l)->a, (i))
Harvey Harrison5638f992008-01-30 13:31:26 +010018
19static inline void local_inc(local_t *l)
20{
Joe Perches69cde652008-03-23 01:02:39 -070021 asm volatile(_ASM_INC "%0"
22 : "+m" (l->a.counter));
Harvey Harrison5638f992008-01-30 13:31:26 +010023}
24
25static inline void local_dec(local_t *l)
26{
Joe Perches69cde652008-03-23 01:02:39 -070027 asm volatile(_ASM_DEC "%0"
28 : "+m" (l->a.counter));
Harvey Harrison5638f992008-01-30 13:31:26 +010029}
30
31static inline void local_add(long i, local_t *l)
32{
Joe Perches69cde652008-03-23 01:02:39 -070033 asm volatile(_ASM_ADD "%1,%0"
34 : "+m" (l->a.counter)
35 : "ir" (i));
Harvey Harrison5638f992008-01-30 13:31:26 +010036}
37
38static inline void local_sub(long i, local_t *l)
39{
Joe Perches69cde652008-03-23 01:02:39 -070040 asm volatile(_ASM_SUB "%1,%0"
41 : "+m" (l->a.counter)
42 : "ir" (i));
Harvey Harrison5638f992008-01-30 13:31:26 +010043}
44
45/**
46 * local_sub_and_test - subtract value from variable and test result
47 * @i: integer value to subtract
48 * @l: pointer to type local_t
49 *
50 * Atomically subtracts @i from @l and returns
51 * true if the result is zero, or false for all
52 * other cases.
53 */
54static inline int local_sub_and_test(long i, local_t *l)
55{
56 unsigned char c;
57
Joe Perches69cde652008-03-23 01:02:39 -070058 asm volatile(_ASM_SUB "%2,%0; sete %1"
59 : "+m" (l->a.counter), "=qm" (c)
60 : "ir" (i) : "memory");
Harvey Harrison5638f992008-01-30 13:31:26 +010061 return c;
62}
63
64/**
65 * local_dec_and_test - decrement and test
66 * @l: pointer to type local_t
67 *
68 * Atomically decrements @l by 1 and
69 * returns true if the result is 0, or false for all other
70 * cases.
71 */
72static inline int local_dec_and_test(local_t *l)
73{
74 unsigned char c;
75
Joe Perches69cde652008-03-23 01:02:39 -070076 asm volatile(_ASM_DEC "%0; sete %1"
77 : "+m" (l->a.counter), "=qm" (c)
78 : : "memory");
Harvey Harrison5638f992008-01-30 13:31:26 +010079 return c != 0;
80}
81
82/**
83 * local_inc_and_test - increment and test
84 * @l: pointer to type local_t
85 *
86 * Atomically increments @l by 1
87 * and returns true if the result is zero, or false for all
88 * other cases.
89 */
90static inline int local_inc_and_test(local_t *l)
91{
92 unsigned char c;
93
Joe Perches69cde652008-03-23 01:02:39 -070094 asm volatile(_ASM_INC "%0; sete %1"
95 : "+m" (l->a.counter), "=qm" (c)
96 : : "memory");
Harvey Harrison5638f992008-01-30 13:31:26 +010097 return c != 0;
98}
99
100/**
101 * local_add_negative - add and test if negative
102 * @i: integer value to add
103 * @l: pointer to type local_t
104 *
105 * Atomically adds @i to @l and returns true
106 * if the result is negative, or false when
107 * result is greater than or equal to zero.
108 */
109static inline int local_add_negative(long i, local_t *l)
110{
111 unsigned char c;
112
Joe Perches69cde652008-03-23 01:02:39 -0700113 asm volatile(_ASM_ADD "%2,%0; sets %1"
114 : "+m" (l->a.counter), "=qm" (c)
115 : "ir" (i) : "memory");
Harvey Harrison5638f992008-01-30 13:31:26 +0100116 return c;
117}
118
119/**
120 * local_add_return - add and return
121 * @i: integer value to add
122 * @l: pointer to type local_t
123 *
124 * Atomically adds @i to @l and returns @i + @l
125 */
126static inline long local_add_return(long i, local_t *l)
127{
128 long __i;
129#ifdef CONFIG_M386
130 unsigned long flags;
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100131 if (unlikely(boot_cpu_data.x86 <= 3))
Harvey Harrison5638f992008-01-30 13:31:26 +0100132 goto no_xadd;
Thomas Gleixner96a388d2007-10-11 11:20:03 +0200133#endif
Harvey Harrison5638f992008-01-30 13:31:26 +0100134 /* Modern 486+ processor */
135 __i = i;
Joe Perches69cde652008-03-23 01:02:39 -0700136 asm volatile(_ASM_XADD "%0, %1;"
137 : "+r" (i), "+m" (l->a.counter)
138 : : "memory");
Harvey Harrison5638f992008-01-30 13:31:26 +0100139 return i + __i;
140
141#ifdef CONFIG_M386
142no_xadd: /* Legacy 386 processor */
143 local_irq_save(flags);
144 __i = local_read(l);
145 local_set(l, i + __i);
146 local_irq_restore(flags);
147 return i + __i;
148#endif
149}
150
151static inline long local_sub_return(long i, local_t *l)
152{
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100153 return local_add_return(-i, l);
Harvey Harrison5638f992008-01-30 13:31:26 +0100154}
155
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100156#define local_inc_return(l) (local_add_return(1, l))
157#define local_dec_return(l) (local_sub_return(1, l))
Harvey Harrison5638f992008-01-30 13:31:26 +0100158
159#define local_cmpxchg(l, o, n) \
160 (cmpxchg_local(&((l)->a.counter), (o), (n)))
161/* Always has a lock prefix */
162#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
163
164/**
165 * local_add_unless - add unless the number is a given value
166 * @l: pointer of type local_t
167 * @a: the amount to add to l...
168 * @u: ...unless l is equal to u.
169 *
170 * Atomically adds @a to @l, so long as it was not @u.
171 * Returns non-zero if @l was not @u, and zero otherwise.
172 */
173#define local_add_unless(l, a, u) \
174({ \
175 long c, old; \
Joe Perches69cde652008-03-23 01:02:39 -0700176 c = local_read((l)); \
Harvey Harrison5638f992008-01-30 13:31:26 +0100177 for (;;) { \
178 if (unlikely(c == (u))) \
179 break; \
Joe Perches69cde652008-03-23 01:02:39 -0700180 old = local_cmpxchg((l), c, c + (a)); \
Harvey Harrison5638f992008-01-30 13:31:26 +0100181 if (likely(old == c)) \
182 break; \
183 c = old; \
184 } \
185 c != (u); \
186})
187#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
188
189/* On x86_32, these are no better than the atomic variants.
190 * On x86-64 these are better than the atomic variants on SMP kernels
191 * because they dont use a lock prefix.
192 */
193#define __local_inc(l) local_inc(l)
194#define __local_dec(l) local_dec(l)
Harvey Harrison01c57fb2008-01-30 13:31:26 +0100195#define __local_add(i, l) local_add((i), (l))
196#define __local_sub(i, l) local_sub((i), (l))
Harvey Harrison5638f992008-01-30 13:31:26 +0100197
H. Peter Anvin1965aae2008-10-22 22:26:29 -0700198#endif /* _ASM_X86_LOCAL_H */