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/*
* cmpxchg*() fallbacks for CPU not supporting these instructions
*/
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/module.h>
#ifndef CONFIG_X86_CMPXCHG
unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)
{
u8 prev;
unsigned long flags;
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
local_irq_save(flags);
prev = *(u8 *)ptr;
if (prev == old)
*(u8 *)ptr = new;
local_irq_restore(flags);
return prev;
}
EXPORT_SYMBOL(cmpxchg_386_u8);
unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new)
{
u16 prev;
unsigned long flags;
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
local_irq_save(flags);
prev = *(u16 *)ptr;
if (prev == old)
*(u16 *)ptr = new;
local_irq_restore(flags);
return prev;
}
EXPORT_SYMBOL(cmpxchg_386_u16);
unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
{
u32 prev;
unsigned long flags;
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
local_irq_save(flags);
prev = *(u32 *)ptr;
if (prev == old)
*(u32 *)ptr = new;
local_irq_restore(flags);
return prev;
}
EXPORT_SYMBOL(cmpxchg_386_u32);
#endif
#ifndef CONFIG_X86_CMPXCHG64
unsigned long long cmpxchg_486_u64(volatile void *ptr, u64 old, u64 new)
{
u64 prev;
unsigned long flags;
/* Poor man's cmpxchg8b for 386 and 486. Unsuitable for SMP */
local_irq_save(flags);
prev = *(u64 *)ptr;
if (prev == old)
*(u64 *)ptr = new;
local_irq_restore(flags);
return prev;
}
EXPORT_SYMBOL(cmpxchg_486_u64);
#endif
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