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authorAvi Kivity <avi@qumranet.com>2007-07-19 14:30:14 +0300
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 14:37:05 -0700
commit2d9ce177e68645945e3366cfe2d66ee3c28cd4f2 (patch)
treea98a3a8b0f1e92f0b8f9ecb44b67bb46c3b4451a
parent3e1f900bff40460d7bbab0ccd1a9efc3c70aee49 (diff)
downloadlinux-linaro-2d9ce177e68645945e3366cfe2d66ee3c28cd4f2.tar.gz
i386: Allow KVM on i386 nonpae
Currently, CONFIG_X86_CMPXCHG64 both enables boot-time checking of the cmpxchg64b feature and enables compilation of the set_64bit() family. Since the option is dependent on PAE, and since KVM depends on set_64bit(), this effectively disables KVM on i386 nopae. Simplify by removing the config option altogether: the boot check is made dependent on CONFIG_X86_PAE directly, and the set_64bit() family is exposed without constraints. It is up to users to check for the feature flag (KVM does not as virtualiation extensions imply its existence). Signed-off-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/i386/Kconfig.cpu5
-rw-r--r--arch/i386/defconfig1
-rw-r--r--arch/um/defconfig1
-rw-r--r--drivers/kvm/Kconfig1
-rw-r--r--include/asm-i386/cmpxchg.h14
-rw-r--r--include/asm-i386/required-features.h2
6 files changed, 6 insertions, 18 deletions
diff --git a/arch/i386/Kconfig.cpu b/arch/i386/Kconfig.cpu
index 9cbe76c3aa3..11a24d54f27 100644
--- a/arch/i386/Kconfig.cpu
+++ b/arch/i386/Kconfig.cpu
@@ -297,11 +297,6 @@ config X86_POPAD_OK
depends on !M386
default y
-config X86_CMPXCHG64
- bool
- depends on X86_PAE
- default y
-
config X86_ALIGNMENT_16
bool
depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1
diff --git a/arch/i386/defconfig b/arch/i386/defconfig
index 1a3a2217b7c..0ac62cdcd3b 100644
--- a/arch/i386/defconfig
+++ b/arch/i386/defconfig
@@ -166,7 +166,6 @@ CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
-CONFIG_X86_CMPXCHG64=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
diff --git a/arch/um/defconfig b/arch/um/defconfig
index a25cd25d55d..1e0f677c2f4 100644
--- a/arch/um/defconfig
+++ b/arch/um/defconfig
@@ -52,7 +52,6 @@ CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
-CONFIG_X86_CMPXCHG64=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
CONFIG_X86_TSC=y
diff --git a/drivers/kvm/Kconfig b/drivers/kvm/Kconfig
index 33fa28a8c19..2f661e5f0da 100644
--- a/drivers/kvm/Kconfig
+++ b/drivers/kvm/Kconfig
@@ -11,7 +11,6 @@ if VIRTUALIZATION
config KVM
tristate "Kernel-based Virtual Machine (KVM) support"
depends on X86 && EXPERIMENTAL
- depends on X86_CMPXCHG64 || 64BIT
---help---
Support hosting fully virtualized guest machines using hardware
virtualization extensions. You will need a fairly recent
diff --git a/include/asm-i386/cmpxchg.h b/include/asm-i386/cmpxchg.h
index 7adcef0cd53..64dcdf46117 100644
--- a/include/asm-i386/cmpxchg.h
+++ b/include/asm-i386/cmpxchg.h
@@ -3,14 +3,16 @@
#include <linux/bitops.h> /* for LOCK_PREFIX */
+/*
+ * Note: if you use set64_bit(), __cmpxchg64(), or their variants, you
+ * you need to test for the feature in boot_cpu_data.
+ */
+
#define xchg(ptr,v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr))))
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))
-
-#ifdef CONFIG_X86_CMPXCHG64
-
/*
* The semantics of XCHGCMP8B are a bit strange, this is why
* there is a loop and the loading of %%eax and %%edx has to
@@ -65,8 +67,6 @@ static inline void __set_64bit_var (unsigned long long *ptr,
__set_64bit(ptr, (unsigned int)(value), (unsigned int)((value)>>32ULL) ) : \
__set_64bit(ptr, ll_low(value), ll_high(value)) )
-#endif
-
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock anyway
* Note 2: xchg has side effect, so that attribute volatile is necessary,
@@ -252,8 +252,6 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
})
#endif
-#ifdef CONFIG_X86_CMPXCHG64
-
static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old,
unsigned long long new)
{
@@ -289,5 +287,3 @@ static inline unsigned long long __cmpxchg64_local(volatile void *ptr,
((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\
(unsigned long long)(n)))
#endif
-
-#endif
diff --git a/include/asm-i386/required-features.h b/include/asm-i386/required-features.h
index 65848a00705..618feb98f9f 100644
--- a/include/asm-i386/required-features.h
+++ b/include/asm-i386/required-features.h
@@ -29,7 +29,7 @@
# define NEED_CMOV 0
#endif
-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_PAE
# define NEED_CX8 (1<<(X86_FEATURE_CX8 & 31))
#else
# define NEED_CX8 0