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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Generic UP xchg and cmpxchg using interrupt disablement. Does not
4 * support SMP.
5 */
6
7#ifndef __ASM_GENERIC_CMPXCHG_H
8#define __ASM_GENERIC_CMPXCHG_H
9
10#ifdef CONFIG_SMP
11#error "Cannot use generic cmpxchg on SMP"
12#endif
13
14#include <linux/types.h>
15#include <linux/irqflags.h>
16
17#ifndef xchg
18
19/*
20 * This function doesn't exist, so you'll get a linker error if
21 * something tries to do an invalidly-sized xchg().
22 */
23extern void __xchg_called_with_bad_pointer(void);
24
25static inline
26unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
27{
28 unsigned long ret, flags;
29
30 switch (size) {
31 case 1:
32#ifdef __xchg_u8
33 return __xchg_u8(x, ptr);
34#else
35 local_irq_save(flags);
36 ret = *(volatile u8 *)ptr;
37 *(volatile u8 *)ptr = x;
38 local_irq_restore(flags);
39 return ret;
40#endif /* __xchg_u8 */
41
42 case 2:
43#ifdef __xchg_u16
44 return __xchg_u16(x, ptr);
45#else
46 local_irq_save(flags);
47 ret = *(volatile u16 *)ptr;
48 *(volatile u16 *)ptr = x;
49 local_irq_restore(flags);
50 return ret;
51#endif /* __xchg_u16 */
52
53 case 4:
54#ifdef __xchg_u32
55 return __xchg_u32(x, ptr);
56#else
57 local_irq_save(flags);
58 ret = *(volatile u32 *)ptr;
59 *(volatile u32 *)ptr = x;
60 local_irq_restore(flags);
61 return ret;
62#endif /* __xchg_u32 */
63
64#ifdef CONFIG_64BIT
65 case 8:
66#ifdef __xchg_u64
67 return __xchg_u64(x, ptr);
68#else
69 local_irq_save(flags);
70 ret = *(volatile u64 *)ptr;
71 *(volatile u64 *)ptr = x;
72 local_irq_restore(flags);
73 return ret;
74#endif /* __xchg_u64 */
75#endif /* CONFIG_64BIT */
76
77 default:
78 __xchg_called_with_bad_pointer();
79 return x;
80 }
81}
82
83#define xchg(ptr, x) ({ \
84 ((__typeof__(*(ptr))) \
85 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
86})
87
88#endif /* xchg */
89
90/*
91 * Atomic compare and exchange.
92 */
93#include <asm-generic/cmpxchg-local.h>
94
95#ifndef cmpxchg_local
96#define cmpxchg_local(ptr, o, n) ({ \
97 ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
98 (unsigned long)(n), sizeof(*(ptr)))); \
99})
100#endif
101
102#ifndef cmpxchg64_local
103#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
104#endif
105
106#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
107#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
108
109#endif /* __ASM_GENERIC_CMPXCHG_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Generic UP xchg and cmpxchg using interrupt disablement. Does not
4 * support SMP.
5 */
6
7#ifndef __ASM_GENERIC_CMPXCHG_H
8#define __ASM_GENERIC_CMPXCHG_H
9
10#ifdef CONFIG_SMP
11#error "Cannot use generic cmpxchg on SMP"
12#endif
13
14#include <linux/types.h>
15#include <linux/irqflags.h>
16
17/*
18 * This function doesn't exist, so you'll get a linker error if
19 * something tries to do an invalidly-sized xchg().
20 */
21extern void __generic_xchg_called_with_bad_pointer(void);
22
23static inline
24unsigned long __generic_xchg(unsigned long x, volatile void *ptr, int size)
25{
26 unsigned long ret, flags;
27
28 switch (size) {
29 case 1:
30#ifdef __xchg_u8
31 return __xchg_u8(x, ptr);
32#else
33 local_irq_save(flags);
34 ret = *(volatile u8 *)ptr;
35 *(volatile u8 *)ptr = x;
36 local_irq_restore(flags);
37 return ret;
38#endif /* __xchg_u8 */
39
40 case 2:
41#ifdef __xchg_u16
42 return __xchg_u16(x, ptr);
43#else
44 local_irq_save(flags);
45 ret = *(volatile u16 *)ptr;
46 *(volatile u16 *)ptr = x;
47 local_irq_restore(flags);
48 return ret;
49#endif /* __xchg_u16 */
50
51 case 4:
52#ifdef __xchg_u32
53 return __xchg_u32(x, ptr);
54#else
55 local_irq_save(flags);
56 ret = *(volatile u32 *)ptr;
57 *(volatile u32 *)ptr = x;
58 local_irq_restore(flags);
59 return ret;
60#endif /* __xchg_u32 */
61
62#ifdef CONFIG_64BIT
63 case 8:
64#ifdef __xchg_u64
65 return __xchg_u64(x, ptr);
66#else
67 local_irq_save(flags);
68 ret = *(volatile u64 *)ptr;
69 *(volatile u64 *)ptr = x;
70 local_irq_restore(flags);
71 return ret;
72#endif /* __xchg_u64 */
73#endif /* CONFIG_64BIT */
74
75 default:
76 __generic_xchg_called_with_bad_pointer();
77 return x;
78 }
79}
80
81#define generic_xchg(ptr, x) ({ \
82 ((__typeof__(*(ptr))) \
83 __generic_xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
84})
85
86/*
87 * Atomic compare and exchange.
88 */
89#include <asm-generic/cmpxchg-local.h>
90
91#define generic_cmpxchg_local(ptr, o, n) ({ \
92 ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o), \
93 (unsigned long)(n), sizeof(*(ptr)))); \
94})
95
96#define generic_cmpxchg64_local(ptr, o, n) \
97 __generic_cmpxchg64_local((ptr), (o), (n))
98
99
100#ifndef arch_xchg
101#define arch_xchg generic_xchg
102#endif
103
104#ifndef arch_cmpxchg_local
105#define arch_cmpxchg_local generic_cmpxchg_local
106#endif
107
108#ifndef arch_cmpxchg64_local
109#define arch_cmpxchg64_local generic_cmpxchg64_local
110#endif
111
112#define arch_cmpxchg arch_cmpxchg_local
113#define arch_cmpxchg64 arch_cmpxchg64_local
114
115#endif /* __ASM_GENERIC_CMPXCHG_H */