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 	__noreturn;
9 
10 /*
11  * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
12  * long parameter, supporting various types of architectures.
13  */
14 static 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  */
53 static 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