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a436ed9c JD |
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 | ||
10 | static 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 | */ | |
22 | static 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 | ||
61 | static 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 | ||
94 | static 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)\ | |
bdda1561 | 131 | ((__typeof__(*(ptr)))__cmpxchg_local((ptr),(unsigned long)(o),\ |
a436ed9c JD |
132 | (unsigned long)(n),sizeof(*(ptr)))) |
133 | ||
134 | #endif |