1#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
2#define __ASM_GENERIC_CMPXCHG_LOCAL_H
3
4#include <linux/types.h>
5#include <linux/irqflags.h>
6
7extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
8	__noreturn;
9
10/*
11 * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
12 * long parameter, supporting various types of architectures.
13 */
14static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
15		unsigned long old, unsigned long new, int size)
16{
17	unsigned long flags, prev;
18
19	/*
20	 * Sanity checking, compile-time.
21	 */
22	if (size == 8 && sizeof(unsigned long) != 8)
23		wrong_size_cmpxchg(ptr);
24
25	raw_local_irq_save(flags);
26	switch (size) {
27	case 1: prev = *(u8 *)ptr;
28		if (prev == old)
29			*(u8 *)ptr = (u8)new;
30		break;
31	case 2: prev = *(u16 *)ptr;
32		if (prev == old)
33			*(u16 *)ptr = (u16)new;
34		break;
35	case 4: prev = *(u32 *)ptr;
36		if (prev == old)
37			*(u32 *)ptr = (u32)new;
38		break;
39	case 8: prev = *(u64 *)ptr;
40		if (prev == old)
41			*(u64 *)ptr = (u64)new;
42		break;
43	default:
44		wrong_size_cmpxchg(ptr);
45	}
46	raw_local_irq_restore(flags);
47	return prev;
48}
49
50/*
51 * Generic version of __cmpxchg64_local. Takes an u64 parameter.
52 */
53static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
54		u64 old, u64 new)
55{
56	u64 prev;
57	unsigned long flags;
58
59	raw_local_irq_save(flags);
60	prev = *(u64 *)ptr;
61	if (prev == old)
62		*(u64 *)ptr = new;
63	raw_local_irq_restore(flags);
64	return prev;
65}
66
67#endif
68