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d550bbd4 DH |
1 | /* 32-bit atomic xchg() and cmpxchg() definitions. |
2 | * | |
3 | * Copyright (C) 1996 David S. Miller (davem@davemloft.net) | |
4 | * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au) | |
5 | * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org) | |
6 | * | |
7 | * Additions by Keith M Wesolowski (wesolows@foobazco.org) based | |
8 | * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>. | |
9 | */ | |
10 | ||
11 | #ifndef __ARCH_SPARC_CMPXCHG__ | |
12 | #define __ARCH_SPARC_CMPXCHG__ | |
13 | ||
d550bbd4 DH |
14 | static inline unsigned long xchg_u32(__volatile__ unsigned long *m, unsigned long val) |
15 | { | |
d550bbd4 DH |
16 | __asm__ __volatile__("swap [%2], %0" |
17 | : "=&r" (val) | |
18 | : "0" (val), "r" (m) | |
19 | : "memory"); | |
20 | return val; | |
d550bbd4 DH |
21 | } |
22 | ||
23 | extern void __xchg_called_with_bad_pointer(void); | |
24 | ||
25 | static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size) | |
26 | { | |
27 | switch (size) { | |
28 | case 4: | |
29 | return xchg_u32(ptr, x); | |
30 | } | |
31 | __xchg_called_with_bad_pointer(); | |
32 | return x; | |
33 | } | |
34 | ||
35 | #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) | |
36 | ||
37 | /* Emulate cmpxchg() the same way we emulate atomics, | |
38 | * by hashing the object address and indexing into an array | |
39 | * of spinlocks to get a bit of performance... | |
40 | * | |
41 | * See arch/sparc/lib/atomic32.c for implementation. | |
42 | * | |
43 | * Cribbed from <asm-parisc/atomic.h> | |
44 | */ | |
45 | #define __HAVE_ARCH_CMPXCHG 1 | |
46 | ||
47 | /* bug catcher for when unsupported size is used - won't link */ | |
48 | extern void __cmpxchg_called_with_bad_pointer(void); | |
49 | /* we only need to support cmpxchg of a u32 on sparc */ | |
50 | extern unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_); | |
51 | ||
52 | /* don't worry...optimizer will get rid of most of this */ | |
53 | static inline unsigned long | |
54 | __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) | |
55 | { | |
56 | switch (size) { | |
57 | case 4: | |
58 | return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_); | |
59 | default: | |
60 | __cmpxchg_called_with_bad_pointer(); | |
61 | break; | |
62 | } | |
63 | return old; | |
64 | } | |
65 | ||
66 | #define cmpxchg(ptr, o, n) \ | |
67 | ({ \ | |
68 | __typeof__(*(ptr)) _o_ = (o); \ | |
69 | __typeof__(*(ptr)) _n_ = (n); \ | |
70 | (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ | |
71 | (unsigned long)_n_, sizeof(*(ptr))); \ | |
72 | }) | |
73 | ||
74 | #include <asm-generic/cmpxchg-local.h> | |
75 | ||
76 | /* | |
77 | * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make | |
78 | * them available. | |
79 | */ | |
80 | #define cmpxchg_local(ptr, o, n) \ | |
81 | ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ | |
82 | (unsigned long)(n), sizeof(*(ptr)))) | |
83 | #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) | |
84 | ||
85 | #endif /* __ARCH_SPARC_CMPXCHG__ */ |