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gerrit-public.fairphone.software / fp2-dev / kernel / msm / a23c58a3ac4090a41e63ae5b69af87b409abe019 / . / include / asm-x86_64 / cmpxchg.h
blob: 09a6b6b6b74dac10a753cf605acd87949d8c3eb9 [file] [log] [blame]
Jeff Dikea436ed92007-05-08 00:35:02 -0700[diff] [blame]1#ifndef __ASM_CMPXCHG_H
2#define __ASM_CMPXCHG_H
3
4#include <asm/alternative.h> /* Provides LOCK_PREFIX */
5
6#define xchg(ptr,v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr))))
7
8#define __xg(x) ((volatile long *)(x))
9
10static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
11{
12 *ptr = val;
13}
14
15#define _set_64bit set_64bit
16
17/*
18 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
19 * Note 2: xchg has side effect, so that attribute volatile is necessary,
20 * but generally the primitive is invalid, *ptr is output argument. --ANK
21 */
22static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
23{
24 switch (size) {
25 case 1:
26 __asm__ __volatile__("xchgb %b0,%1"
27 :"=q" (x)
28 :"m" (*__xg(ptr)), "0" (x)
29 :"memory");
30 break;
31 case 2:
32 __asm__ __volatile__("xchgw %w0,%1"
33 :"=r" (x)
34 :"m" (*__xg(ptr)), "0" (x)
35 :"memory");
36 break;
37 case 4:
38 __asm__ __volatile__("xchgl %k0,%1"
39 :"=r" (x)
40 :"m" (*__xg(ptr)), "0" (x)
41 :"memory");
42 break;
43 case 8:
44 __asm__ __volatile__("xchgq %0,%1"
45 :"=r" (x)
46 :"m" (*__xg(ptr)), "0" (x)
47 :"memory");
48 break;
49 }
50 return x;
51}
52
53/*
54 * Atomic compare and exchange. Compare OLD with MEM, if identical,
55 * store NEW in MEM. Return the initial value in MEM. Success is
56 * indicated by comparing RETURN with OLD.
57 */
58
59#define __HAVE_ARCH_CMPXCHG 1
60
61static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
62 unsigned long new, int size)
63{
64 unsigned long prev;
65 switch (size) {
66 case 1:
67 __asm__ __volatile__(LOCK_PREFIX "cmpxchgb %b1,%2"
68 : "=a"(prev)
69 : "q"(new), "m"(*__xg(ptr)), "0"(old)
70 : "memory");
71 return prev;
72 case 2:
73 __asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2"
74 : "=a"(prev)
75 : "r"(new), "m"(*__xg(ptr)), "0"(old)
76 : "memory");
77 return prev;
78 case 4:
79 __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %k1,%2"
80 : "=a"(prev)
81 : "r"(new), "m"(*__xg(ptr)), "0"(old)
82 : "memory");
83 return prev;
84 case 8:
85 __asm__ __volatile__(LOCK_PREFIX "cmpxchgq %1,%2"
86 : "=a"(prev)
87 : "r"(new), "m"(*__xg(ptr)), "0"(old)
88 : "memory");
89 return prev;
90 }
91 return old;
92}
93
94static inline unsigned long __cmpxchg_local(volatile void *ptr,
95 unsigned long old, unsigned long new, int size)
96{
97 unsigned long prev;
98 switch (size) {
99 case 1:
100 __asm__ __volatile__("cmpxchgb %b1,%2"
101 : "=a"(prev)
102 : "q"(new), "m"(*__xg(ptr)), "0"(old)
103 : "memory");
104 return prev;
105 case 2:
106 __asm__ __volatile__("cmpxchgw %w1,%2"
107 : "=a"(prev)
108 : "r"(new), "m"(*__xg(ptr)), "0"(old)
109 : "memory");
110 return prev;
111 case 4:
112 __asm__ __volatile__("cmpxchgl %k1,%2"
113 : "=a"(prev)
114 : "r"(new), "m"(*__xg(ptr)), "0"(old)
115 : "memory");
116 return prev;
117 case 8:
118 __asm__ __volatile__("cmpxchgq %1,%2"
119 : "=a"(prev)
120 : "r"(new), "m"(*__xg(ptr)), "0"(old)
121 : "memory");
122 return prev;
123 }
124 return old;
125}
126
127#define cmpxchg(ptr,o,n)\
128 ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
129 (unsigned long)(n),sizeof(*(ptr))))
130#define cmpxchg_local(ptr,o,n)\
131 ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
132 (unsigned long)(n),sizeof(*(ptr))))
133
134#endif