linux-kernel - [patch] x86, avx: don't use avx instructions with "noxsave" boot param

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Message-ID: <1343688375.3696.597.camel@sbsiddha-desk.sc.intel.com>
Date:	Mon, 30 Jul 2012 15:46:15 -0700
From:	Suresh Siddha <suresh.b.siddha@...el.com>
To:	hpa@...or.com, james.t.kukunas@...ux.intel.com, neilb@...e.de
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [patch] x86, avx: don't use avx instructions with "noxsave" boot
 param

Check the kernel has indeed enabled xsave before using AVX instructions.

Fixes the kernel boot panic with "noxsave" boot parameter.

Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
---
 arch/x86/include/asm/xor_avx.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xor_avx.h b/arch/x86/include/asm/xor_avx.h
index 2510d35..77987cd 100644
--- a/arch/x86/include/asm/xor_avx.h
+++ b/arch/x86/include/asm/xor_avx.h
@@ -197,12 +197,12 @@ static struct xor_block_template xor_block_avx = {
 
 #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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