[PATCH 3.16 092/192] crypto: sha1-ssse3 - Disable avx2

[Ben Hutchings]

3.16.49-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

commit b82ce24426a4071da9529d726057e4e642948667 upstream.

It has been reported that sha1-avx2 can cause page faults by reading
beyond the end of the input.  This patch disables it until it can be
fixed.

Fixes: 7c1da8d0d046 ("crypto: sha - SHA1 transform x86_64 AVX2")
Reported-by: Jan Stancek <jstancek@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/arch/x86/crypto/sha1_ssse3_glue.c
+++ b/arch/x86/crypto/sha1_ssse3_glue.c
@@ -224,7 +224,8 @@ static bool __init avx_usable(void)
 #ifdef CONFIG_AS_AVX2
 static bool __init avx2_usable(void)
 {
-	if (avx_usable() && cpu_has_avx2 && boot_cpu_has(X86_FEATURE_BMI1) &&
+	if (false && avx_usable() && cpu_has_avx2 &&
+	    boot_cpu_has(X86_FEATURE_BMI1) &&
 	    boot_cpu_has(X86_FEATURE_BMI2))
 		return true;