1/*
 2 * cmpxchg*() fallbacks for CPU not supporting these instructions
 3 */
 4
 5#include <linux/kernel.h>
 6#include <linux/smp.h>
 7#include <linux/module.h>
 8
 9#ifndef CONFIG_X86_CMPXCHG
10unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)
11{
12	u8 prev;
13	unsigned long flags;
14
15	/* Poor man's cmpxchg for 386. Unsuitable for SMP */
16	local_irq_save(flags);
17	prev = *(u8 *)ptr;
18	if (prev == old)
19		*(u8 *)ptr = new;
20	local_irq_restore(flags);
21	return prev;
22}
23EXPORT_SYMBOL(cmpxchg_386_u8);
24
25unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new)
26{
27	u16 prev;
28	unsigned long flags;
29
30	/* Poor man's cmpxchg for 386. Unsuitable for SMP */
31	local_irq_save(flags);
32	prev = *(u16 *)ptr;
33	if (prev == old)
34		*(u16 *)ptr = new;
35	local_irq_restore(flags);
36	return prev;
37}
38EXPORT_SYMBOL(cmpxchg_386_u16);
39
40unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
41{
42	u32 prev;
43	unsigned long flags;
44
45	/* Poor man's cmpxchg for 386. Unsuitable for SMP */
46	local_irq_save(flags);
47	prev = *(u32 *)ptr;
48	if (prev == old)
49		*(u32 *)ptr = new;
50	local_irq_restore(flags);
51	return prev;
52}
53EXPORT_SYMBOL(cmpxchg_386_u32);
54#endif