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x86, 386 removal: Remove CONFIG_CMPXCHG 

All 486+ CPUs support CMPXCHG, so remove the fallback 386 support
code.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1354132230-21854-3-git-send-email-hpa@linux.intel.com
This commit is contained in:
H. Peter Anvin 2012-11-28 11:50:24 -08:00
parent eb068e7810
commit d55c5a93db
6 changed files with 1 additions and 117 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/Kconfig.cpu
View File

@ -297,9 +297,6 @@ config X86_INTERNODE_CACHE_SHIFT
default "12" if X86_VSMP
default X86_L1_CACHE_SHIFT
config X86_CMPXCHG
def_bool y
config X86_L1_CACHE_SHIFT
int
default "7" if MPENTIUM4 || MPSC

55
arch/x86/include/asm/cmpxchg_32.h
View File

@ -34,9 +34,7 @@ static inline void set_64bit(volatile u64 *ptr, u64 value)
: "memory");
}
#ifdef CONFIG_X86_CMPXCHG
#define __HAVE_ARCH_CMPXCHG 1
#endif
#ifdef CONFIG_X86_CMPXCHG64
#define cmpxchg64(ptr, o, n) \
@ -73,59 +71,6 @@ static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new)
return prev;
}
#ifndef CONFIG_X86_CMPXCHG
/*
* Building a kernel capable running on 80386. It may be necessary to
* simulate the cmpxchg on the 80386 CPU. For that purpose we define
* a function for each of the sizes we support.
*/
extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
unsigned long new, int size)
{
switch (size) {
case 1:
return cmpxchg_386_u8(ptr, old, new);
case 2:
return cmpxchg_386_u16(ptr, old, new);
case 4:
return cmpxchg_386_u32(ptr, old, new);
}
return old;
}
#define cmpxchg(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
if (likely(boot_cpu_data.x86 > 3)) \
__ret = (__typeof__(*(ptr)))__cmpxchg((ptr), \
(unsigned long)(o), (unsigned long)(n), \
sizeof(*(ptr))); \
else \
__ret = (__typeof__(*(ptr)))cmpxchg_386((ptr), \
(unsigned long)(o), (unsigned long)(n), \
sizeof(*(ptr))); \
__ret; \
})
#define cmpxchg_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
if (likely(boot_cpu_data.x86 > 3)) \
__ret = (__typeof__(*(ptr)))__cmpxchg_local((ptr), \
(unsigned long)(o), (unsigned long)(n), \
sizeof(*(ptr))); \
else \
__ret = (__typeof__(*(ptr)))cmpxchg_386((ptr), \
(unsigned long)(o), (unsigned long)(n), \
sizeof(*(ptr))); \
__ret; \
})
#endif
#ifndef CONFIG_X86_CMPXCHG64
/*
* Building a kernel capable running on 80386 and 80486. It may be necessary

3
arch/x86/include/asm/percpu.h
View File

@ -406,7 +406,6 @@ do { \
#define this_cpu_xchg_2(pcp, nval) percpu_xchg_op(pcp, nval)
#define this_cpu_xchg_4(pcp, nval) percpu_xchg_op(pcp, nval)
#ifndef CONFIG_M386
#define __this_cpu_add_return_1(pcp, val) percpu_add_return_op(pcp, val)
#define __this_cpu_add_return_2(pcp, val) percpu_add_return_op(pcp, val)
#define __this_cpu_add_return_4(pcp, val) percpu_add_return_op(pcp, val)
@ -421,8 +420,6 @@ do { \
#define this_cpu_cmpxchg_2(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
#define this_cpu_cmpxchg_4(pcp, oval, nval) percpu_cmpxchg_op(pcp, oval, nval)
#endif /* !CONFIG_M386 */
#ifdef CONFIG_X86_CMPXCHG64
#define percpu_cmpxchg8b_double(pcp1, pcp2, o1, o2, n1, n2) \
({ \

1
arch/x86/lib/Makefile
View File

@ -32,7 +32,6 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += checksum_32.o
lib-y += strstr_32.o
lib-y += string_32.o
lib-y += cmpxchg.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
lib-y += cmpxchg8b_emu.o atomic64_386_32.o
endif

54
arch/x86/lib/cmpxchg.c
View File

@ -1,54 +0,0 @@
/*
* 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

2
arch/x86/xen/Kconfig
View File

@ -7,7 +7,7 @@ config XEN
select PARAVIRT
select PARAVIRT_CLOCK
depends on X86_64 || (X86_32 && X86_PAE && !X86_VISWS)
depends on X86_CMPXCHG && X86_TSC
depends on X86_TSC
help
This is the Linux Xen port. Enabling this will allow the
kernel to boot in a paravirtualized environment under the