[RFC][PATCH 2/3] x86: add more disabled features

From: Dave Hansen
Date: Fri Jun 20 2014 - 12:17:44 EST



There are a few other features than MPX that we can make
assumptions about at compile-time based on compile options.
Add them to disabled-features.h

---

b/arch/x86/include/asm/cpufeature.h | 18 ------------------
b/arch/x86/include/asm/disabled-features.h | 16 ++++++++++++++--
2 files changed, 14 insertions(+), 20 deletions(-)

diff -puN arch/x86/include/asm/cpufeature.h~x86-disabled_features-addmore arch/x86/include/asm/cpufeature.h
--- a/arch/x86/include/asm/cpufeature.h~x86-disabled_features-addmore 2014-06-20 09:16:08.420317511 -0700
+++ b/arch/x86/include/asm/cpufeature.h 2014-06-20 09:16:08.425317736 -0700
@@ -357,32 +357,14 @@ extern const char * const x86_power_flag
#define cpu_has_eager_fpu boot_cpu_has(X86_FEATURE_EAGER_FPU)
#define cpu_has_topoext boot_cpu_has(X86_FEATURE_TOPOEXT)

-#ifdef CONFIG_X86_INTEL_MPX
-#define cpu_has_mpx boot_cpu_has(X86_FEATURE_MPX)
-#else
-#define cpu_has_mpx 0
-#endif /* CONFIG_X86_INTEL_MPX */
-
#ifdef CONFIG_X86_64

-#undef cpu_has_vme
-#define cpu_has_vme 0
-
#undef cpu_has_pae
#define cpu_has_pae ___BUG___

#undef cpu_has_mp
#define cpu_has_mp 1

-#undef cpu_has_k6_mtrr
-#define cpu_has_k6_mtrr 0
-
-#undef cpu_has_cyrix_arr
-#define cpu_has_cyrix_arr 0
-
-#undef cpu_has_centaur_mcr
-#define cpu_has_centaur_mcr 0
-
#endif /* CONFIG_X86_64 */

#if __GNUC__ >= 4
diff -puN arch/x86/include/asm/disabled-features.h~x86-disabled_features-addmore arch/x86/include/asm/disabled-features.h
--- a/arch/x86/include/asm/disabled-features.h~x86-disabled_features-addmore 2014-06-20 09:16:08.422317600 -0700
+++ b/arch/x86/include/asm/disabled-features.h 2014-06-20 09:16:08.426317782 -0700
@@ -16,13 +16,25 @@
# define HAVE_MPX 0
#endif

+#ifdef CONFIG_X86_64
+# define HAVE_VME (1<<(X86_FEATURE_VME & 31))
+# define HAVE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31))
+# define HAVE_CYRIX_ARR (1<<(X86_FEATURE_CYRIX_ARR & 31))
+# define HAVE_CENTAUR_MCR (1<<(X86_FEATURE_CENTAUR_MCR & 31))
+#else
+# define HAVE_VME 0
+# define HAVE_K6_MTRR 0
+# define HAVE_CYRIX_ARR 0
+# define HAVE_CENTAUR_MCR 0
+#endif /* CONFIG_X86_64 */
+
/*
* Make sure to add features to the correct mask
*/
-#define DISABLED_MASK0 0
+#define DISABLED_MASK0 (HAVE_VME|HAVE_K6_MTRR)
#define DISABLED_MASK1 0
#define DISABLED_MASK2 0
-#define DISABLED_MASK3 0
+#define DISABLED_MASK3 (HAVE_CYRIX_ARR|HAVE_CENTAUR_MCR)
#define DISABLED_MASK4 0
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
_
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