[ 14/16] crypto: xor - Check for osxsave as well as avx in crypto/xor

From: Greg Kroah-Hartman
Date: Thu Sep 12 2013 - 14:16:54 EST


3.11-stable review patch. If anyone has any objections, please let me know.

------------------

From: John Haxby <john.haxby@xxxxxxxxxx>

commit edb6f29464afc65fc73767540b854abf63ae7144 upstream.

This affects xen pv guests with sufficiently old versions of xen and
sufficiently new hardware. On such a system, a guest with a btrfs
root won't even boot.

Signed-off-by: John Haxby <john.haxby@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Reported-by: Michael Marineau <michael.marineau@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/include/asm/xor_avx.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/xor_avx.h
+++ b/arch/x86/include/asm/xor_avx.h
@@ -167,12 +167,12 @@ static struct xor_block_template xor_blo

#define AVX_XOR_SPEED \
do { \
- if (cpu_has_avx) \
+ if (cpu_has_avx && cpu_has_osxsave) \
xor_speed(&xor_block_avx); \
} while (0)

#define AVX_SELECT(FASTEST) \
- (cpu_has_avx ? &xor_block_avx : FASTEST)
+ (cpu_has_avx && cpu_has_osxsave ? &xor_block_avx : FASTEST)

#else



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