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