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

From: Dave Hansen
Date: Thu Sep 11 2014 - 17:16:04 EST


From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

The original motivation for these patches was for an Intel CPU
feature called MPX. The patch to add a disabled feature for it
will go in with the other parts of the support.

But, in the meantime, 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 and check them
with cpu_feature_enabled().

Note that this gets rid of the last things that needed an #ifdef
CONFIG_X86_64 in cpufeature.h. Yay!

Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
---

b/arch/x86/include/asm/cpufeature.h | 20 --------------------
b/arch/x86/include/asm/disabled-features.h | 16 ++++++++++++++--
b/arch/x86/kernel/cpu/common.c | 2 +-
b/arch/x86/kernel/cpu/mtrr/main.c | 6 +++---
4 files changed, 18 insertions(+), 26 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 2014-09-11 14:11:32.541086689 -0700
+++ b/arch/x86/include/asm/cpufeature.h 2014-09-11 14:11:32.550087101 -0700
@@ -324,7 +324,6 @@ extern const char * const x86_bug_flags[
} while (0)

#define cpu_has_fpu boot_cpu_has(X86_FEATURE_FPU)
-#define cpu_has_vme boot_cpu_has(X86_FEATURE_VME)
#define cpu_has_de boot_cpu_has(X86_FEATURE_DE)
#define cpu_has_pse boot_cpu_has(X86_FEATURE_PSE)
#define cpu_has_tsc boot_cpu_has(X86_FEATURE_TSC)
@@ -343,9 +342,6 @@ extern const char * const x86_bug_flags[
#define cpu_has_avx2 boot_cpu_has(X86_FEATURE_AVX2)
#define cpu_has_ht boot_cpu_has(X86_FEATURE_HT)
#define cpu_has_nx boot_cpu_has(X86_FEATURE_NX)
-#define cpu_has_k6_mtrr boot_cpu_has(X86_FEATURE_K6_MTRR)
-#define cpu_has_cyrix_arr boot_cpu_has(X86_FEATURE_CYRIX_ARR)
-#define cpu_has_centaur_mcr boot_cpu_has(X86_FEATURE_CENTAUR_MCR)
#define cpu_has_xstore boot_cpu_has(X86_FEATURE_XSTORE)
#define cpu_has_xstore_enabled boot_cpu_has(X86_FEATURE_XSTORE_EN)
#define cpu_has_xcrypt boot_cpu_has(X86_FEATURE_XCRYPT)
@@ -380,22 +376,6 @@ extern const char * const x86_bug_flags[
#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_64
-
-#undef cpu_has_vme
-#define cpu_has_vme 0
-
-#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
extern void warn_pre_alternatives(void);
extern bool __static_cpu_has_safe(u16 bit);
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 2014-09-11 14:11:32.543086781 -0700
+++ b/arch/x86/include/asm/disabled-features.h 2014-09-11 14:11:32.550087101 -0700
@@ -10,13 +10,25 @@
* cpu_feature_enabled().
*/

+#ifdef CONFIG_X86_64
+# define DISABLE_VME (1<<(X86_FEATURE_VME & 31))
+# define DISABLE_K6_MTRR (1<<(X86_FEATURE_K6_MTRR & 31))
+# define DISABLE_CYRIX_ARR (1<<(X86_FEATURE_CYRIX_ARR & 31))
+# define DISABLE_CENTAUR_MCR (1<<(X86_FEATURE_CENTAUR_MCR & 31))
+#else
+# define DISABLE_VME 0
+# define DISABLE_K6_MTRR 0
+# define DISABLE_CYRIX_ARR 0
+# define DISABLE_CENTAUR_MCR 0
+#endif /* CONFIG_X86_64 */
+
/*
* Make sure to add features to the correct mask
*/
-#define DISABLED_MASK0 0
+#define DISABLED_MASK0 (DISABLE_VME)
#define DISABLED_MASK1 0
#define DISABLED_MASK2 0
-#define DISABLED_MASK3 0
+#define DISABLED_MASK3 (DISABLE_CYRIX_ARR|DISABLE_CENTAUR_MCR|DISABLE_K6_MTRR)
#define DISABLED_MASK4 0
#define DISABLED_MASK5 0
#define DISABLED_MASK6 0
diff -puN arch/x86/kernel/cpu/common.c~x86-disabled_features-addmore arch/x86/kernel/cpu/common.c
--- a/arch/x86/kernel/cpu/common.c~x86-disabled_features-addmore 2014-09-11 14:11:32.545086872 -0700
+++ b/arch/x86/kernel/cpu/common.c 2014-09-11 14:11:32.562087651 -0700
@@ -1391,7 +1391,7 @@ void cpu_init(void)

printk(KERN_INFO "Initializing CPU#%d\n", cpu);

- if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
+ if (cpu_feature_enabled(X86_FEATURE_VME) || cpu_has_tsc || cpu_has_de)
clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);

load_current_idt();
diff -puN arch/x86/kernel/cpu/mtrr/main.c~x86-disabled_features-addmore arch/x86/kernel/cpu/mtrr/main.c
--- a/arch/x86/kernel/cpu/mtrr/main.c~x86-disabled_features-addmore 2014-09-11 14:11:32.546086917 -0700
+++ b/arch/x86/kernel/cpu/mtrr/main.c 2014-09-11 14:11:32.563087697 -0700
@@ -707,7 +707,7 @@ void __init mtrr_bp_init(void)
} else {
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_AMD:
- if (cpu_has_k6_mtrr) {
+ if (cpu_feature_enabled(X86_FEATURE_K6_MTRR)) {
/* Pre-Athlon (K6) AMD CPU MTRRs */
mtrr_if = mtrr_ops[X86_VENDOR_AMD];
size_or_mask = SIZE_OR_MASK_BITS(32);
@@ -715,14 +715,14 @@ void __init mtrr_bp_init(void)
}
break;
case X86_VENDOR_CENTAUR:
- if (cpu_has_centaur_mcr) {
+ if (cpu_feature_enabled(X86_FEATURE_CENTAUR_MCR)) {
mtrr_if = mtrr_ops[X86_VENDOR_CENTAUR];
size_or_mask = SIZE_OR_MASK_BITS(32);
size_and_mask = 0;
}
break;
case X86_VENDOR_CYRIX:
- if (cpu_has_cyrix_arr) {
+ if (cpu_feature_enabled(X86_FEATURE_CYRIX_ARR)) {
mtrr_if = mtrr_ops[X86_VENDOR_CYRIX];
size_or_mask = SIZE_OR_MASK_BITS(32);
size_and_mask = 0;
_
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/