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[linux.git] / arch / sparc / include / asm / cmpxchg_32.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* 32-bit atomic xchg() and cmpxchg() definitions.
3  *
4  * Copyright (C) 1996 David S. Miller ([email protected])
5  * Copyright (C) 2000 Anton Blanchard ([email protected])
6  * Copyright (C) 2007 Kyle McMartin ([email protected])
7  *
8  * Additions by Keith M Wesolowski ([email protected]) based
9  * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <[email protected]>.
10  */
11
12 #ifndef __ARCH_SPARC_CMPXCHG__
13 #define __ARCH_SPARC_CMPXCHG__
14
15 unsigned long __xchg_u32(volatile u32 *m, u32 new);
16 void __xchg_called_with_bad_pointer(void);
17
18 static inline unsigned long __arch_xchg(unsigned long x, __volatile__ void * ptr, int size)
19 {
20         switch (size) {
21         case 4:
22                 return __xchg_u32(ptr, x);
23         }
24         __xchg_called_with_bad_pointer();
25         return x;
26 }
27
28 #define arch_xchg(ptr,x) ({(__typeof__(*(ptr)))__arch_xchg((unsigned long)(x),(ptr),sizeof(*(ptr)));})
29
30 /* Emulate cmpxchg() the same way we emulate atomics,
31  * by hashing the object address and indexing into an array
32  * of spinlocks to get a bit of performance...
33  *
34  * See arch/sparc/lib/atomic32.c for implementation.
35  *
36  * Cribbed from <asm-parisc/atomic.h>
37  */
38
39 /* bug catcher for when unsupported size is used - won't link */
40 void __cmpxchg_called_with_bad_pointer(void);
41 /* we only need to support cmpxchg of a u32 on sparc */
42 unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
43
44 /* don't worry...optimizer will get rid of most of this */
45 static inline unsigned long
46 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
47 {
48         switch (size) {
49         case 4:
50                 return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
51         default:
52                 __cmpxchg_called_with_bad_pointer();
53                 break;
54         }
55         return old;
56 }
57
58 #define arch_cmpxchg(ptr, o, n)                                         \
59 ({                                                                      \
60         __typeof__(*(ptr)) _o_ = (o);                                   \
61         __typeof__(*(ptr)) _n_ = (n);                                   \
62         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,       \
63                         (unsigned long)_n_, sizeof(*(ptr)));            \
64 })
65
66 u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new);
67 #define arch_cmpxchg64(ptr, old, new)   __cmpxchg_u64(ptr, old, new)
68
69 #include <asm-generic/cmpxchg-local.h>
70
71 /*
72  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
73  * them available.
74  */
75 #define arch_cmpxchg_local(ptr, o, n)                                          \
76         ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o),\
77                         (unsigned long)(n), sizeof(*(ptr))))
78 #define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
79
80 #endif /* __ARCH_SPARC_CMPXCHG__ */
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