Commit 774400a3 authored by Thomas Petazzoni's avatar Thomas Petazzoni Committed by Ingo Molnar
Browse files

x86: move cmpxchg fallbacks to a generic place 



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: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: michael@free-electrons.com
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8bfcb396

arch/x86/kernel/cpu/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
obj-y			:= intel_cacheinfo.o addon_cpuid_features.o

obj-y			+= proc.o feature_names.o



obj-$(CONFIG_X86_32)	+= common.o bugs.o

obj-$(CONFIG_X86_32)	+= common.o bugs.o cmpxchg.o

obj-$(CONFIG_X86_64)	+= common_64.o bugs_64.o

obj-$(CONFIG_X86_32)	+= amd.o

obj-$(CONFIG_X86_64)	+= amd_64.o

arch/x86/kernel/cpu/cmpxchg.c

0 → 100644
+72 −0
Original line number Diff line number Diff line 
/*

 * 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

arch/x86/kernel/cpu/intel.c

+0 −64
Original line number Diff line number Diff line
@@ -307,69 +307,5 @@ static struct cpu_dev intel_cpu_dev __cpuinitdata = { 


cpu_vendor_dev_register(X86_VENDOR_INTEL, &intel_cpu_dev);



#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



/* arch_initcall(intel_cpu_init); */

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