1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
3*4882a593Smuzhiyun #define __ASM_GENERIC_CMPXCHG_LOCAL_H
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun #include <linux/types.h>
6*4882a593Smuzhiyun #include <linux/irqflags.h>
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
9*4882a593Smuzhiyun __noreturn;
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun /*
12*4882a593Smuzhiyun * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
13*4882a593Smuzhiyun * long parameter, supporting various types of architectures.
14*4882a593Smuzhiyun */
__cmpxchg_local_generic(volatile void * ptr,unsigned long old,unsigned long new,int size)15*4882a593Smuzhiyun static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
16*4882a593Smuzhiyun unsigned long old, unsigned long new, int size)
17*4882a593Smuzhiyun {
18*4882a593Smuzhiyun unsigned long flags, prev;
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun /*
21*4882a593Smuzhiyun * Sanity checking, compile-time.
22*4882a593Smuzhiyun */
23*4882a593Smuzhiyun if (size == 8 && sizeof(unsigned long) != 8)
24*4882a593Smuzhiyun wrong_size_cmpxchg(ptr);
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun raw_local_irq_save(flags);
27*4882a593Smuzhiyun switch (size) {
28*4882a593Smuzhiyun case 1: prev = *(u8 *)ptr;
29*4882a593Smuzhiyun if (prev == old)
30*4882a593Smuzhiyun *(u8 *)ptr = (u8)new;
31*4882a593Smuzhiyun break;
32*4882a593Smuzhiyun case 2: prev = *(u16 *)ptr;
33*4882a593Smuzhiyun if (prev == old)
34*4882a593Smuzhiyun *(u16 *)ptr = (u16)new;
35*4882a593Smuzhiyun break;
36*4882a593Smuzhiyun case 4: prev = *(u32 *)ptr;
37*4882a593Smuzhiyun if (prev == old)
38*4882a593Smuzhiyun *(u32 *)ptr = (u32)new;
39*4882a593Smuzhiyun break;
40*4882a593Smuzhiyun case 8: prev = *(u64 *)ptr;
41*4882a593Smuzhiyun if (prev == old)
42*4882a593Smuzhiyun *(u64 *)ptr = (u64)new;
43*4882a593Smuzhiyun break;
44*4882a593Smuzhiyun default:
45*4882a593Smuzhiyun wrong_size_cmpxchg(ptr);
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun raw_local_irq_restore(flags);
48*4882a593Smuzhiyun return prev;
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun /*
52*4882a593Smuzhiyun * Generic version of __cmpxchg64_local. Takes an u64 parameter.
53*4882a593Smuzhiyun */
__cmpxchg64_local_generic(volatile void * ptr,u64 old,u64 new)54*4882a593Smuzhiyun static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
55*4882a593Smuzhiyun u64 old, u64 new)
56*4882a593Smuzhiyun {
57*4882a593Smuzhiyun u64 prev;
58*4882a593Smuzhiyun unsigned long flags;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun raw_local_irq_save(flags);
61*4882a593Smuzhiyun prev = *(u64 *)ptr;
62*4882a593Smuzhiyun if (prev == old)
63*4882a593Smuzhiyun *(u64 *)ptr = new;
64*4882a593Smuzhiyun raw_local_irq_restore(flags);
65*4882a593Smuzhiyun return prev;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun #endif
69