Re: [PATCH 05/11] x86, mpx: add MPX to disaabled features

From: Sergei Shtylyov
Date: Fri Nov 14 2014 - 12:56:54 EST


Hello.

On 11/14/2014 06:18 PM, Dave Hansen wrote:

From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

This allows us to use cpu_feature_enabled(X86_FEATURE_MPX) as
both a runtime and compile-time check.

When CONFIG_X86_INTEL_MPX is disabled,
cpu_feature_enabled(X86_FEATURE_MPX) will evaluate at
compile-time to 0. If CONFIG_X86_INTEL_MPX=y, then the cpuid
flag will be checked at runtime.

Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
---

b/arch/x86/include/asm/disabled-features.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff -puN arch/x86/include/asm/disabled-features.h~mpx-v11-add-MPX-to-disaabled-features arch/x86/include/asm/disabled-features.h
--- a/arch/x86/include/asm/disabled-features.h~mpx-v11-add-MPX-to-disaabled-features 2014-11-14 07:06:22.297610243 -0800
+++ b/arch/x86/include/asm/disabled-features.h 2014-11-14 07:06:22.300610378 -0800
[...]
@@ -34,6 +40,6 @@
#define DISABLED_MASK6 0
#define DISABLED_MASK7 0
#define DISABLED_MASK8 0
-#define DISABLED_MASK9 0
+#define DISABLED_MASK9 (DISABLE_MPX)

These parens are not really needed. Sorry to be a PITA and not saying this before.

[...]

WBR, Sergei

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