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authorJeff Dike <jdike@addtoit.com>2007-05-08 03:35:02 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 14:15:20 -0400
commita436ed9c5106b41606cbb55ab3b28389fe8ae04f (patch)
treeb8df0bde6d7eb2808c37da815d8857396ee1eaf1 /include/asm-x86_64/cmpxchg.h
parent5dc12ddee93d63d7107cbbf70db23476d7b30e43 (diff)
x86: create asm/cmpxchg.h
i386: Rearrange the cmpxchg code to allow atomic.h to get it without needing to include system.h. This kills warnings in the UML build from atomic.h about implicit declarations of cmpxchg symbols. The i386 build presumably isn't seeing this because a separate inclusion of system.h is covering it over. The cmpxchg stuff is moved to asm-i386/cmpxchg.h, with an include left in system.h for the benefit of generic code which expects cmpxchg there. Meanwhile, atomic.h includes cmpxchg.h. This causes no noticable damage to the i386 build. x86_64: Move cmpxchg into its own header. atomic.h already included system.h, so this is changed to include cmpxchg.h. This is purely cleanup - it's not fixing any warnings - so if the x86_64 system.h isn't considered as cleanup-worthy as i386, then this can be dropped. It causes no noticable damage to the x86_64 build. uml: The i386 and x86_64 cmpxchg patches require an asm-um/cmpxchg.h for the UML build. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-x86_64/cmpxchg.h')
-rw-r--r--include/asm-x86_64/cmpxchg.h134
1 files changed, 134 insertions, 0 deletions
diff --git a/include/asm-x86_64/cmpxchg.h b/include/asm-x86_64/cmpxchg.h
new file mode 100644
index 000000000000..09a6b6b6b74d
--- /dev/null
+++ b/include/asm-x86_64/cmpxchg.h
@@ -0,0 +1,134 @@
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