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
|
#ifndef ASM_X86_CMPXCHG_H
#define ASM_X86_CMPXCHG_H
#include <linux/compiler.h>
#include <asm/alternative.h> /* Provides LOCK_PREFIX */
/*
* Non-existant functions to indicate usage errors at link time
* (or compile-time if the compiler implements __compiletime_error().
*/
extern void __xchg_wrong_size(void)
__compiletime_error("Bad argument size for xchg");
extern void __cmpxchg_wrong_size(void)
__compiletime_error("Bad argument size for cmpxchg");
extern void __xadd_wrong_size(void)
__compiletime_error("Bad argument size for xadd");
extern void __add_wrong_size(void)
__compiletime_error("Bad argument size for add");
/*
* Constants for operation sizes. On 32-bit, the 64-bit size it set to
* -1 because sizeof will never return -1, thereby making those switch
* case statements guaranteeed dead code which the compiler will
* eliminate, and allowing the "missing symbol in the default case" to
* indicate a usage error.
*/
#define __X86_CASE_B 1
#define __X86_CASE_W 2
#define __X86_CASE_L 4
#ifdef CONFIG_64BIT
#define __X86_CASE_Q 8
#else
#define __X86_CASE_Q -1 /* sizeof will never return -1 */
#endif
/*
* An exchange-type operation, which takes a value and a pointer, and
* returns a the old value.
*/
#define __xchg_op(ptr, arg, op, lock) \
({ \
__typeof__ (*(ptr)) __ret = (arg); \
switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \
asm volatile (lock #op "b %b0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_W: \
asm volatile (lock #op "w %w0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_L: \
asm volatile (lock #op "l %0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_Q: \
asm volatile (lock #op "q %q0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
default: \
__ ## op ## _wrong_size(); \
} \
__ret; \
})
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
* Since this is generally used to protect other memory information, we
* use "asm volatile" and "memory" clobbers to prevent gcc from moving
* information around.
*/
#define xchg(ptr, v) __xchg_op((ptr), (v), xchg, "")
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/
#define __raw_cmpxchg(ptr, old, new, size, lock) \
({ \
__typeof__(*(ptr)) __ret; \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
switch (size) { \
case __X86_CASE_B: \
{ \
volatile u8 *__ptr = (volatile u8 *)(ptr); \
asm volatile(lock "cmpxchgb %2,%1" \
: "=a" (__ret), "+m" (*__ptr) \
: "q" (__new), "0" (__old) \
: "memory"); \
break; \
} \
case __X86_CASE_W: \
{ \
volatile u16 *__ptr = (volatile u16 *)(ptr); \
asm volatile(lock "cmpxchgw %2,%1" \
: "=a" (__ret), "+m" (*__ptr) \
: "r" (__new), "0" (__old) \
: "memory"); \
break; \
} \
case __X86_CASE_L: \
{ \
volatile u32 *__ptr = (volatile u32 *)(ptr); \
asm volatile(lock "cmpxchgl %2,%1" \
: "=a" (__ret), "+m" (*__ptr) \
: "r" (__new), "0" (__old) \
: "memory"); \
break; \
} \
case __X86_CASE_Q: \
{ \
volatile u64 *__ptr = (volatile u64 *)(ptr); \
asm volatile(lock "cmpxchgq %2,%1" \
: "=a" (__ret), "+m" (*__ptr) \
: "r" (__new), "0" (__old) \
: "memory"); \
break; \
} \
default: \
__cmpxchg_wrong_size(); \
} \
__ret; \
})
#define __cmpxchg(ptr, old, new, size) \
__raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
#define __sync_cmpxchg(ptr, old, new, size) \
__raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
#define __cmpxchg_local(ptr, old, new, size) \
__raw_cmpxchg((ptr), (old), (new), (size), "")
#ifdef CONFIG_X86_32
# include "cmpxchg_32.h"
#else
# include "cmpxchg_64.h"
#endif
#ifdef __HAVE_ARCH_CMPXCHG
#define cmpxchg(ptr, old, new) \
__cmpxchg(ptr, old, new, sizeof(*(ptr)))
#define sync_cmpxchg(ptr, old, new) \
__sync_cmpxchg(ptr, old, new, sizeof(*(ptr)))
#define cmpxchg_local(ptr, old, new) \
__cmpxchg_local(ptr, old, new, sizeof(*(ptr)))
#endif
/*
* xadd() adds "inc" to "*ptr" and atomically returns the previous
* value of "*ptr".
*
* xadd() is locked when multiple CPUs are online
* xadd_sync() is always locked
* xadd_local() is never locked
*/
#define __xadd(ptr, inc, lock) __xchg_op((ptr), (inc), xadd, lock)
#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX)
#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ")
#define xadd_local(ptr, inc) __xadd((ptr), (inc), "")
#define __add(ptr, inc, lock) \
({ \
__typeof__ (*(ptr)) __ret = (inc); \
switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \
asm volatile (lock "addb %b1, %0\n" \
: "+m" (*(ptr)) : "ri" (inc) \
: "memory", "cc"); \
break; \
case __X86_CASE_W: \
asm volatile (lock "addw %w1, %0\n" \
: "+m" (*(ptr)) : "ri" (inc) \
: "memory", "cc"); \
break; \
case __X86_CASE_L: \
asm volatile (lock "addl %1, %0\n" \
: "+m" (*(ptr)) : "ri" (inc) \
: "memory", "cc"); \
break; \
case __X86_CASE_Q: \
asm volatile (lock "addq %1, %0\n" \
: "+m" (*(ptr)) : "ri" (inc) \
: "memory", "cc"); \
break; \
default: \
__add_wrong_size(); \
} \
__ret; \
})
/*
* add_*() adds "inc" to "*ptr"
*
* __add() takes a lock prefix
* add_smp() is locked when multiple CPUs are online
* add_sync() is always locked
*/
#define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX)
#define add_sync(ptr, inc) __add((ptr), (inc), "lock; ")
#define __cmpxchg_double(pfx, p1, p2, o1, o2, n1, n2) \
({ \
bool __ret; \
__typeof__(*(p1)) __old1 = (o1), __new1 = (n1); \
__typeof__(*(p2)) __old2 = (o2), __new2 = (n2); \
BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long)); \
BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long)); \
VM_BUG_ON((unsigned long)(p1) % (2 * sizeof(long))); \
VM_BUG_ON((unsigned long)((p1) + 1) != (unsigned long)(p2)); \
asm volatile(pfx "cmpxchg%c4b %2; sete %0" \
: "=a" (__ret), "+d" (__old2), \
"+m" (*(p1)), "+m" (*(p2)) \
: "i" (2 * sizeof(long)), "a" (__old1), \
"b" (__new1), "c" (__new2)); \
__ret; \
})
#define cmpxchg_double(p1, p2, o1, o2, n1, n2) \
__cmpxchg_double(LOCK_PREFIX, p1, p2, o1, o2, n1, n2)
#define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \
__cmpxchg_double(, p1, p2, o1, o2, n1, n2)
#endif /* ASM_X86_CMPXCHG_H */
|
