1 #ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
2 #define __ASM_GENERIC_CMPXCHG_LOCAL_H
3 
4 #include <linux/types.h>
5 
6 extern 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  */
12 static 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  */
51 static 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
66