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 */
__cmpxchg_local_generic(volatile void * ptr,unsigned long old,unsigned long new,int size)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 */
__cmpxchg64_local_generic(volatile void * ptr,u64 old,u64 new)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