mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-17 16:14:25 +08:00
774400a3ba
arch/x86/kernel/cpu/intel.c defines a few fallback functions (cmpxchg_*()) that are used when the CPU doesn't support cmpxchg and/or cmpxchg64 natively. However, while defined in an Intel-specific file, these functions are also used for CPUs from other vendors when they don't support cmpxchg and/or cmpxchg64. This breaks the compilation when support for Intel CPUs is disabled. This patch moves these functions to a new arch/x86/kernel/cpu/cmpxchg.c file, unconditionally compiled when X86_32 is enabled. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: michael@free-electrons.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
73 lines
1.5 KiB
C
73 lines
1.5 KiB
C
/*
|
|
* 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
|
|
|