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 */
14 extern void __xchg_called_with_bad_pointer(void);
15
16 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
17 extern unsigned long __xchg8(char, volatile char *);
18 extern unsigned long __xchg32(int, volatile int *);
19 #ifdef CONFIG_64BIT
20 extern unsigned long __xchg64(unsigned long, volatile unsigned long *);
21 #endif
22
23 /* optimizer better get rid of switch since size is a constant */
24 static 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 */
57 extern void __cmpxchg_called_with_bad_pointer(void);
58
59 /* __cmpxchg_u... defined in arch/parisc/lib/bitops.c */
60 extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
61 extern u16 __cmpxchg_u16(volatile u16 *ptr, u16 old, u16 new_);
62 extern u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
63 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
64
65 /* don't worry...optimizer will get rid of most of this */
66 static 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
89 static 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_ */
123
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