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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
#ifndef __ARCH_I386_ATOMIC__
#define __ARCH_I386_ATOMIC__
#include <linux/config.h>
#include <linux/compiler.h>
#include <asm/processor.h>
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*/
#ifdef CONFIG_SMP
#define LOCK "lock ; "
#else
#define LOCK ""
#endif
/*
* Make sure gcc doesn't try to be clever and move things around
* on us. We need to use _exactly_ the address the user gave us,
* not some alias that contains the same information.
*/
typedef struct { volatile int counter; } atomic_t;
#define ATOMIC_INIT(i) { (i) }
/**
* atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v.
*/
#define atomic_read(v) ((v)->counter)
/**
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define atomic_set(v,i) (((v)->counter) = (i))
/**
* atomic_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v.
*/
static __inline__ void atomic_add(int i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "addl %1,%0"
:"=m" (v->counter)
:"ir" (i), "m" (v->counter));
}
/**
* atomic_sub - subtract the atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v.
*/
static __inline__ void atomic_sub(int i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "subl %1,%0"
:"=m" (v->counter)
:"ir" (i), "m" (v->counter));
}
/**
* atomic_sub_and_test - subtract value from variable and test result
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v and returns
* true if the result is zero, or false for all
* other cases.
*/
static __inline__ int atomic_sub_and_test(int i, atomic_t *v)
{
unsigned char c;
__asm__ __volatile__(
LOCK "subl %2,%0; sete %1"
:"=m" (v->counter), "=qm" (c)
:"ir" (i), "m" (v->counter) : "memory");
return c;
}
/**
* atomic_inc - increment atomic variable
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1.
*/
static __inline__ void atomic_inc(atomic_t *v)
{
__asm__ __volatile__(
LOCK "incl %0"
:"=m" (v->counter)
:"m" (v->counter));
}
/**
* atomic_dec - decrement atomic variable
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1.
*/
static __inline__ void atomic_dec(atomic_t *v)
{
__asm__ __volatile__(
LOCK "decl %0"
:"=m" (v->counter)
:"m" (v->counter));
}
/**
* atomic_dec_and_test - decrement and test
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1 and
* returns true if the result is 0, or false for all other
* cases.
*/
static __inline__ int atomic_dec_and_test(atomic_t *v)
{
unsigned char c;
__asm__ __volatile__(
LOCK "decl %0; sete %1"
:"=m" (v->counter), "=qm" (c)
:"m" (v->counter) : "memory");
return c != 0;
}
/**
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
static __inline__ int atomic_inc_and_test(atomic_t *v)
{
unsigned char c;
__asm__ __volatile__(
LOCK "incl %0; sete %1"
:"=m" (v->counter), "=qm" (c)
:"m" (v->counter) : "memory");
return c != 0;
}
/**
* atomic_add_negative - add and test if negative
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns true
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
static __inline__ int atomic_add_negative(int i, atomic_t *v)
{
unsigned char c;
__asm__ __volatile__(
LOCK "addl %2,%0; sets %1"
:"=m" (v->counter), "=qm" (c)
:"ir" (i), "m" (v->counter) : "memory");
return c;
}
/**
* atomic_add_return - add and return
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns @i + @v
*/
static __inline__ int atomic_add_return(int i, atomic_t *v)
{
int __i;
#ifdef CONFIG_M386
if(unlikely(boot_cpu_data.x86==3))
goto no_xadd;
#endif
/* Modern 486+ processor */
__i = i;
__asm__ __volatile__(
LOCK "xaddl %0, %1;"
:"=r"(i)
:"m"(v->counter), "0"(i));
return i + __i;
#ifdef CONFIG_M386
no_xadd: /* Legacy 386 processor */
local_irq_disable();
__i = atomic_read(v);
atomic_set(v, i + __i);
local_irq_enable();
return i + __i;
#endif
}
static __inline__ int atomic_sub_return(int i, atomic_t *v)
{
return atomic_add_return(-i,v);
}
#define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
/**
* atomic_add_unless - add unless the number is a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
#define atomic_add_unless(v, a, u) \
({ \
int c, old; \
c = atomic_read(v); \
while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
c = old; \
c != (u); \
})
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#define atomic_inc_return(v) (atomic_add_return(1,v))
#define atomic_dec_return(v) (atomic_sub_return(1,v))
/* These are x86-specific, used by some header files */
#define atomic_clear_mask(mask, addr) \
__asm__ __volatile__(LOCK "andl %0,%1" \
: : "r" (~(mask)),"m" (*addr) : "memory")
#define atomic_set_mask(mask, addr) \
__asm__ __volatile__(LOCK "orl %0,%1" \
: : "r" (mask),"m" (*(addr)) : "memory")
/* Atomic operations are already serializing on x86 */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()
#define smp_mb__before_atomic_inc() barrier()
#define smp_mb__after_atomic_inc() barrier()
#include <asm-generic/atomic.h>
#endif
|
