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Linux kernel mirror (for testing)
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1#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
2#define __ASM_GENERIC_CMPXCHG_LOCAL_H
3
4#include <linux/types.h>
5
6extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
7
8/*
9 * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
10 * long parameter, supporting various types of architectures.
11 */
12static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
13 unsigned long old, unsigned long new, int size)
14{
15 unsigned long flags, prev;
16
17 /*
18 * Sanity checking, compile-time.
19 */
20 if (size == 8 && sizeof(unsigned long) != 8)
21 wrong_size_cmpxchg(ptr);
22
23 local_irq_save(flags);
24 switch (size) {
25 case 1: prev = *(u8 *)ptr;
26 if (prev == old)
27 *(u8 *)ptr = (u8)new;
28 break;
29 case 2: prev = *(u16 *)ptr;
30 if (prev == old)
31 *(u16 *)ptr = (u16)new;
32 break;
33 case 4: prev = *(u32 *)ptr;
34 if (prev == old)
35 *(u32 *)ptr = (u32)new;
36 break;
37 case 8: prev = *(u64 *)ptr;
38 if (prev == old)
39 *(u64 *)ptr = (u64)new;
40 break;
41 default:
42 wrong_size_cmpxchg(ptr);
43 }
44 local_irq_restore(flags);
45 return prev;
46}
47
48/*
49 * Generic version of __cmpxchg64_local. Takes an u64 parameter.
50 */
51static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
52 u64 old, u64 new)
53{
54 u64 prev;
55 unsigned long flags;
56
57 local_irq_save(flags);
58 prev = *(u64 *)ptr;
59 if (prev == old)
60 *(u64 *)ptr = new;
61 local_irq_restore(flags);
62 return prev;
63}
64
65#endif