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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * forked from parisc asm/atomic.h which was:
4 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
5 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
6 */
7
8#ifndef _ASM_PARISC_CMPXCHG_H_
9#define _ASM_PARISC_CMPXCHG_H_
10
11/* This should get optimized out since it's never called.
12** Or get a link error if xchg is used "wrong".
13*/
14extern void __xchg_called_with_bad_pointer(void);
15
16/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
17extern unsigned long __xchg8(char, volatile char *);
18extern unsigned long __xchg32(int, volatile int *);
19#ifdef CONFIG_64BIT
20extern unsigned long __xchg64(unsigned long, volatile unsigned long *);
21#endif
22
23/* optimizer better get rid of switch since size is a constant */
24static inline unsigned long
25__arch_xchg(unsigned long x, volatile void *ptr, int size)
26{
27 switch (size) {
28#ifdef CONFIG_64BIT
29 case 8: return __xchg64(x, (volatile unsigned long *) ptr);
30#endif
31 case 4: return __xchg32((int) x, (volatile int *) ptr);
32 case 1: return __xchg8((char) x, (volatile char *) ptr);
33 }
34 __xchg_called_with_bad_pointer();
35 return x;
36}
37
38/*
39** REVISIT - Abandoned use of LDCW in xchg() for now:
40** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
41** o and while we are at it, could CONFIG_64BIT code use LDCD too?
42**
43** if (__builtin_constant_p(x) && (x == NULL))
44** if (((unsigned long)p & 0xf) == 0)
45** return __ldcw(p);
46*/
47#define arch_xchg(ptr, x) \
48({ \
49 __typeof__(*(ptr)) __ret; \
50 __typeof__(*(ptr)) _x_ = (x); \
51 __ret = (__typeof__(*(ptr))) \
52 __arch_xchg((unsigned long)_x_, (ptr), sizeof(*(ptr))); \
53 __ret; \
54})
55
56/* bug catcher for when unsupported size is used - won't link */
57extern void __cmpxchg_called_with_bad_pointer(void);
58
59/* __cmpxchg_u... defined in arch/parisc/lib/bitops.c */
60extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
61extern u16 __cmpxchg_u16(volatile u16 *ptr, u16 old, u16 new_);
62extern u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
63extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
64
65/* don't worry...optimizer will get rid of most of this */
66static inline unsigned long
67__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
68{
69 return
70#ifdef CONFIG_64BIT
71 size == 8 ? __cmpxchg_u64(ptr, old, new_) :
72#endif
73 size == 4 ? __cmpxchg_u32(ptr, old, new_) :
74 size == 2 ? __cmpxchg_u16(ptr, old, new_) :
75 size == 1 ? __cmpxchg_u8(ptr, old, new_) :
76 (__cmpxchg_called_with_bad_pointer(), old);
77}
78
79#define arch_cmpxchg(ptr, o, n) \
80({ \
81 __typeof__(*(ptr)) _o_ = (o); \
82 __typeof__(*(ptr)) _n_ = (n); \
83 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
84 (unsigned long)_n_, sizeof(*(ptr))); \
85})
86
87#include <asm-generic/cmpxchg-local.h>
88
89static inline unsigned long __cmpxchg_local(volatile void *ptr,
90 unsigned long old,
91 unsigned long new_, int size)
92{
93 switch (size) {
94#ifdef CONFIG_64BIT
95 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
96#endif
97 case 4: return __cmpxchg_u32(ptr, old, new_);
98 default:
99 return __generic_cmpxchg_local(ptr, old, new_, size);
100 }
101}
102
103/*
104 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
105 * them available.
106 */
107#define arch_cmpxchg_local(ptr, o, n) \
108 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
109 (unsigned long)(n), sizeof(*(ptr))))
110#ifdef CONFIG_64BIT
111#define arch_cmpxchg64_local(ptr, o, n) \
112({ \
113 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
114 cmpxchg_local((ptr), (o), (n)); \
115})
116#else
117#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
118#endif
119
120#define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
121
122#endif /* _ASM_PARISC_CMPXCHG_H_ */