1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
#ifndef _ASM_X86_LOCAL_H
#define _ASM_X86_LOCAL_H
#include <linux/percpu.h>
#include <linux/atomic.h>
#include <asm/asm.h>
typedef struct {
atomic_long_t a;
} local_t;
#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
#define local_read(l) atomic_long_read(&(l)->a)
#define local_set(l, i) atomic_long_set(&(l)->a, (i))
static inline void local_inc(local_t *l)
{
asm volatile(_ASM_INC "%0"
: "+m" (l->a.counter));
}
static inline void local_dec(local_t *l)
{
asm volatile(_ASM_DEC "%0"
: "+m" (l->a.counter));
}
static inline void local_add(long i, local_t *l)
{
asm volatile(_ASM_ADD "%1,%0"
: "+m" (l->a.counter)
: "ir" (i));
}
static inline void local_sub(long i, local_t *l)
{
asm volatile(_ASM_SUB "%1,%0"
: "+m" (l->a.counter)
: "ir" (i));
}
/**
* local_sub_and_test - subtract value from variable and test result
* @i: integer value to subtract
* @l: pointer to type local_t
*
* Atomically subtracts @i from @l and returns
* true if the result is zero, or false for all
* other cases.
*/
static inline int local_sub_and_test(long i, local_t *l)
{
unsigned char c;
asm volatile(_ASM_SUB "%2,%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: "ir" (i) : "memory");
return c;
}
/**
* local_dec_and_test - decrement and test
* @l: pointer to type local_t
*
* Atomically decrements @l by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
static inline int local_dec_and_test(local_t *l)
{
unsigned char c;
asm volatile(_ASM_DEC "%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: : "memory");
return c != 0;
}
/**
* local_inc_and_test - increment and test
* @l: pointer to type local_t
*
* Atomically increments @l by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
static inline int local_inc_and_test(local_t *l)
{
unsigned char c;
asm volatile(_ASM_INC "%0; sete %1"
: "+m" (l->a.counter), "=qm" (c)
: : "memory");
return c != 0;
}
/**
* local_add_negative - add and test if negative
* @i: integer value to add
* @l: pointer to type local_t
*
* Atomically adds @i to @l and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
static inline int local_add_negative(long i, local_t *l)
{
unsigned char c;
asm volatile(_ASM_ADD "%2,%0; sets %1"
: "+m" (l->a.counter), "=qm" (c)
: "ir" (i) : "memory");
return c;
}
/**
* local_add_return - add and return
* @i: integer value to add
* @l: pointer to type local_t
*
* Atomically adds @i to @l and returns @i + @l
*/
static inline long local_add_return(long i, local_t *l)
{
long __i;
#ifdef CONFIG_M386
unsigned long flags;
if (unlikely(boot_cpu_data.x86 <= 3))
goto no_xadd;
#endif
/* Modern 486+ processor */
__i = i;
asm volatile(_ASM_XADD "%0, %1;"
: "+r" (i), "+m" (l->a.counter)
: : "memory");
return i + __i;
#ifdef CONFIG_M386
no_xadd: /* Legacy 386 processor */
local_irq_save(flags);
__i = local_read(l);
local_set(l, i + __i);
local_irq_restore(flags);
return i + __i;
#endif
}
static inline long local_sub_return(long i, local_t *l)
{
return local_add_return(-i, l);
}
#define local_inc_return(l) (local_add_return(1, l))
#define local_dec_return(l) (local_sub_return(1, l))
#define local_cmpxchg(l, o, n) \
(cmpxchg_local(&((l)->a.counter), (o), (n)))
/* Always has a lock prefix */
#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
/**
* local_add_unless - add unless the number is a given value
* @l: pointer of type local_t
* @a: the amount to add to l...
* @u: ...unless l is equal to u.
*
* Atomically adds @a to @l, so long as it was not @u.
* Returns non-zero if @l was not @u, and zero otherwise.
*/
#define local_add_unless(l, a, u) \
({ \
long c, old; \
c = local_read((l)); \
for (;;) { \
if (unlikely(c == (u))) \
break; \
old = local_cmpxchg((l), c, c + (a)); \
if (likely(old == c)) \
break; \
c = old; \
} \
c != (u); \
})
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
/* On x86_32, these are no better than the atomic variants.
* On x86-64 these are better than the atomic variants on SMP kernels
* because they dont use a lock prefix.
*/
#define __local_inc(l) local_inc(l)
#define __local_dec(l) local_dec(l)
#define __local_add(i, l) local_add((i), (l))
#define __local_sub(i, l) local_sub((i), (l))
#endif /* _ASM_X86_LOCAL_H */
|
