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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * forked from parisc asm/atomic.h which was:
3 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
4 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
5 */
6
7#ifndef _ASM_PARISC_CMPXCHG_H_
8#define _ASM_PARISC_CMPXCHG_H_
9
10/* This should get optimized out since it's never called.
11** Or get a link error if xchg is used "wrong".
12*/
13extern void __xchg_called_with_bad_pointer(void);
14
15/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
16extern unsigned long __xchg8(char, char *);
17extern unsigned long __xchg32(int, int *);
18#ifdef CONFIG_64BIT
19extern unsigned long __xchg64(unsigned long, unsigned long *);
20#endif
21
22/* optimizer better get rid of switch since size is a constant */
23static inline unsigned long
24__xchg(unsigned long x, __volatile__ void *ptr, int size)
25{
26 switch (size) {
27#ifdef CONFIG_64BIT
28 case 8: return __xchg64(x, (unsigned long *) ptr);
29#endif
30 case 4: return __xchg32((int) x, (int *) ptr);
31 case 1: return __xchg8((char) x, (char *) ptr);
32 }
33 __xchg_called_with_bad_pointer();
34 return x;
35}
36
37/*
38** REVISIT - Abandoned use of LDCW in xchg() for now:
39** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
40** o and while we are at it, could CONFIG_64BIT code use LDCD too?
41**
42** if (__builtin_constant_p(x) && (x == NULL))
43** if (((unsigned long)p & 0xf) == 0)
44** return __ldcw(p);
45*/
46#define xchg(ptr, x) \
47 ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
48
49/* bug catcher for when unsupported size is used - won't link */
50extern void __cmpxchg_called_with_bad_pointer(void);
51
52/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
53extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
54 unsigned int new_);
55extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
56
57/* don't worry...optimizer will get rid of most of this */
58static inline unsigned long
59__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
60{
61 switch (size) {
62#ifdef CONFIG_64BIT
63 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
64#endif
65 case 4: return __cmpxchg_u32((unsigned int *)ptr,
66 (unsigned int)old, (unsigned int)new_);
67 }
68 __cmpxchg_called_with_bad_pointer();
69 return old;
70}
71
72#define cmpxchg(ptr, o, n) \
73({ \
74 __typeof__(*(ptr)) _o_ = (o); \
75 __typeof__(*(ptr)) _n_ = (n); \
76 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
77 (unsigned long)_n_, sizeof(*(ptr))); \
78})
79
80#include <asm-generic/cmpxchg-local.h>
81
82static inline unsigned long __cmpxchg_local(volatile void *ptr,
83 unsigned long old,
84 unsigned long new_, int size)
85{
86 switch (size) {
87#ifdef CONFIG_64BIT
88 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
89#endif
90 case 4: return __cmpxchg_u32(ptr, old, new_);
91 default:
92 return __cmpxchg_local_generic(ptr, old, new_, size);
93 }
94}
95
96/*
97 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
98 * them available.
99 */
100#define cmpxchg_local(ptr, o, n) \
101 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
102 (unsigned long)(n), sizeof(*(ptr))))
103#ifdef CONFIG_64BIT
104#define cmpxchg64_local(ptr, o, n) \
105({ \
106 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
107 cmpxchg_local((ptr), (o), (n)); \
108})
109#else
110#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
111#endif
112
113#define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
114
115#endif /* _ASM_PARISC_CMPXCHG_H_ */