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>
7 #ifndef _ASM_PARISC_CMPXCHG_H_
8 #define _ASM_PARISC_CMPXCHG_H_
10 /* This should get optimized out since it's never called.
11 ** Or get a link error if xchg is used "wrong".
13 extern void __xchg_called_with_bad_pointer(void);
15 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
16 extern unsigned long __xchg8(char, char *);
17 extern unsigned long __xchg32(int, int *);
19 extern unsigned long __xchg64(unsigned long, unsigned long *);
22 /* optimizer better get rid of switch since size is a constant */
23 static inline unsigned long
24 __xchg(unsigned long x, __volatile__ void *ptr, int size)
28 case 8: return __xchg64(x, (unsigned long *) ptr);
30 case 4: return __xchg32((int) x, (int *) ptr);
31 case 1: return __xchg8((char) x, (char *) ptr);
33 __xchg_called_with_bad_pointer();
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?
42 ** if (__builtin_constant_p(x) && (x == NULL))
43 ** if (((unsigned long)p & 0xf) == 0)
46 #define xchg(ptr, x) \
48 __typeof__(*(ptr)) __ret; \
49 __typeof__(*(ptr)) _x_ = (x); \
50 __ret = (__typeof__(*(ptr))) \
51 __xchg((unsigned long)_x_, (ptr), sizeof(*(ptr))); \
55 /* bug catcher for when unsupported size is used - won't link */
56 extern void __cmpxchg_called_with_bad_pointer(void);
58 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
59 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
61 extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr,
62 unsigned long old, unsigned long new_);
64 /* don't worry...optimizer will get rid of most of this */
65 static inline unsigned long
66 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
70 case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
72 case 4: return __cmpxchg_u32((unsigned int *)ptr,
73 (unsigned int)old, (unsigned int)new_);
75 __cmpxchg_called_with_bad_pointer();
79 #define cmpxchg(ptr, o, n) \
81 __typeof__(*(ptr)) _o_ = (o); \
82 __typeof__(*(ptr)) _n_ = (n); \
83 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
84 (unsigned long)_n_, sizeof(*(ptr))); \
87 #include <asm-generic/cmpxchg-local.h>
89 static inline unsigned long __cmpxchg_local(volatile void *ptr,
91 unsigned long new_, int size)
95 case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
97 case 4: return __cmpxchg_u32(ptr, old, new_);
99 return __cmpxchg_local_generic(ptr, old, new_, size);
104 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
107 #define cmpxchg_local(ptr, o, n) \
108 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
109 (unsigned long)(n), sizeof(*(ptr))))
111 #define cmpxchg64_local(ptr, o, n) \
113 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
114 cmpxchg_local((ptr), (o), (n)); \
117 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
120 #endif /* _ASM_PARISC_CMPXCHG_H_ */