x86, mpx: Add MPX to disabled features

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@linux.intel.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-mips@linux-mips.org
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141114151823.B358EAD2@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/disabled-features.h

@@ -10,6 +10,12 @@
  * cpu_feature_enabled().
  */
 
+#ifdef CONFIG_X86_INTEL_MPX
+# define DISABLE_MPX	0
+#else
+# define DISABLE_MPX	(1<<(X86_FEATURE_MPX & 31))
+#endif
+
 #ifdef CONFIG_X86_64
 # define DISABLE_VME		(1<<(X86_FEATURE_VME & 31))
 # define DISABLE_K6_MTRR	(1<<(X86_FEATURE_K6_MTRR & 31))
@@ -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)
 
 #endif /* _ASM_X86_DISABLED_FEATURES_H */