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#define __HAVE_ARCH_CMPXCHG	1
50
51/* bug catcher for when unsupported size is used - won't link */
52extern void __cmpxchg_called_with_bad_pointer(void);
53
54/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
55extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
56				   unsigned int new_);
57extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr,
58				   unsigned long old, unsigned long new_);
59
60/* don't worry...optimizer will get rid of most of this */
61static inline unsigned long
62__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
63{
64	switch (size) {
65#ifdef CONFIG_64BIT
66	case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_);
67#endif
68	case 4: return __cmpxchg_u32((unsigned int *)ptr,
69				     (unsigned int)old, (unsigned int)new_);
70	}
71	__cmpxchg_called_with_bad_pointer();
72	return old;
73}
74
75#define cmpxchg(ptr, o, n)						 \
76({									 \
77	__typeof__(*(ptr)) _o_ = (o);					 \
78	__typeof__(*(ptr)) _n_ = (n);					 \
79	(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,	 \
80				    (unsigned long)_n_, sizeof(*(ptr))); \
81})
82
83#include <asm-generic/cmpxchg-local.h>
84
85static inline unsigned long __cmpxchg_local(volatile void *ptr,
86				      unsigned long old,
87				      unsigned long new_, int size)
88{
89	switch (size) {
90#ifdef CONFIG_64BIT
91	case 8:	return __cmpxchg_u64((unsigned long *)ptr, old, new_);
92#endif
93	case 4:	return __cmpxchg_u32(ptr, old, new_);
94	default:
95		return __cmpxchg_local_generic(ptr, old, new_, size);
96	}
97}
98
99/*
100 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
101 * them available.
102 */
103#define cmpxchg_local(ptr, o, n)					\
104	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
105			(unsigned long)(n), sizeof(*(ptr))))
106#ifdef CONFIG_64BIT
107#define cmpxchg64_local(ptr, o, n)					\
108({									\
109	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
110	cmpxchg_local((ptr), (o), (n));					\
111})
112#else
113#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
114#endif
115
116#endif /* _ASM_PARISC_CMPXCHG_H_ */
117