From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> There are two CPUID bits for protection keys. One is for whether the CPU contains the feature, and the other will appear set once the OS enables protection keys. Specifically: Bit 04: OSPKE. If 1, OS has set CR4.PKE to enable Protection keys (and the RDPKRU/WRPKRU instructions) This is because userspace can not see CR4 contents, but it can see CPUID contents. X86_FEATURE_PKU is referred to as "PKU" in the hardware documentation: CPUID.(EAX=07H,ECX=0H):ECX.PKU [bit 3] X86_FEATURE_OSPKE is "OSPKU": CPUID.(EAX=07H,ECX=0H):ECX.OSPKE [bit 4] These are the first CPU features which need to look at the ECX word in CPUID leaf 0x7, so this patch also includes fetching that word in to the cpuinfo->x86_capability[] array. Add it to the disabled-features mask when its config option is off. Even though we are not using it here, we also extend the REQUIRED_MASK_BIT_SET() macro to keep it mirroring the DISABLED_MASK_BIT_SET() version. This means that in almost all code, you should use: cpu_has(c, X86_FEATURE_PKU) and *not* the CONFIG option. Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- b/arch/x86/include/asm/cpufeature.h | 56 ++++++++++++++++++----------- b/arch/x86/include/asm/disabled-features.h | 13 ++++++ b/arch/x86/include/asm/required-features.h | 5 ++ b/arch/x86/kernel/cpu/common.c | 1 4 files changed, 54 insertions(+), 21 deletions(-) diff -puN arch/x86/include/asm/cpufeature.h~pkeys-01-cpuid arch/x86/include/asm/cpufeature.h --- a/arch/x86/include/asm/cpufeature.h~pkeys-01-cpuid 2016-01-06 15:50:04.310097377 -0800 +++ b/arch/x86/include/asm/cpufeature.h 2016-01-06 15:50:04.318097738 -0800 @@ -12,7 +12,7 @@ #include <asm/disabled-features.h> #endif -#define NCAPINTS 14 /* N 32-bit words worth of info */ +#define NCAPINTS 15 /* N 32-bit words worth of info */ #define NBUGINTS 1 /* N 32-bit bug flags */ /* @@ -258,6 +258,10 @@ /* AMD-defined CPU features, CPUID level 0x80000008 (ebx), word 13 */ #define X86_FEATURE_CLZERO (13*32+0) /* CLZERO instruction */ +/* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 13 */ +#define X86_FEATURE_PKU (14*32+ 3) /* Protection Keys for Userspace */ +#define X86_FEATURE_OSPKE (14*32+ 4) /* OS Protection Keys Enable */ + /* * BUG word(s) */ @@ -298,28 +302,38 @@ extern const char * const x86_bug_flags[ test_bit(bit, (unsigned long *)((c)->x86_capability)) #define REQUIRED_MASK_BIT_SET(bit) \ - ( (((bit)>>5)==0 && (1UL<<((bit)&31) & REQUIRED_MASK0)) || \ - (((bit)>>5)==1 && (1UL<<((bit)&31) & REQUIRED_MASK1)) || \ - (((bit)>>5)==2 && (1UL<<((bit)&31) & REQUIRED_MASK2)) || \ - (((bit)>>5)==3 && (1UL<<((bit)&31) & REQUIRED_MASK3)) || \ - (((bit)>>5)==4 && (1UL<<((bit)&31) & REQUIRED_MASK4)) || \ - (((bit)>>5)==5 && (1UL<<((bit)&31) & REQUIRED_MASK5)) || \ - (((bit)>>5)==6 && (1UL<<((bit)&31) & REQUIRED_MASK6)) || \ - (((bit)>>5)==7 && (1UL<<((bit)&31) & REQUIRED_MASK7)) || \ - (((bit)>>5)==8 && (1UL<<((bit)&31) & REQUIRED_MASK8)) || \ - (((bit)>>5)==9 && (1UL<<((bit)&31) & REQUIRED_MASK9)) ) + ( (((bit)>>5)==0 && (1UL<<((bit)&31) & REQUIRED_MASK0 )) || \ + (((bit)>>5)==1 && (1UL<<((bit)&31) & REQUIRED_MASK1 )) || \ + (((bit)>>5)==2 && (1UL<<((bit)&31) & REQUIRED_MASK2 )) || \ + (((bit)>>5)==3 && (1UL<<((bit)&31) & REQUIRED_MASK3 )) || \ + (((bit)>>5)==4 && (1UL<<((bit)&31) & REQUIRED_MASK4 )) || \ + (((bit)>>5)==5 && (1UL<<((bit)&31) & REQUIRED_MASK5 )) || \ + (((bit)>>5)==6 && (1UL<<((bit)&31) & REQUIRED_MASK6 )) || \ + (((bit)>>5)==7 && (1UL<<((bit)&31) & REQUIRED_MASK7 )) || \ + (((bit)>>5)==8 && (1UL<<((bit)&31) & REQUIRED_MASK8 )) || \ + (((bit)>>5)==9 && (1UL<<((bit)&31) & REQUIRED_MASK9 )) || \ + (((bit)>>5)==10 && (1UL<<((bit)&31) & REQUIRED_MASK10)) || \ + (((bit)>>5)==11 && (1UL<<((bit)&31) & REQUIRED_MASK11)) || \ + (((bit)>>5)==12 && (1UL<<((bit)&31) & REQUIRED_MASK12)) || \ + (((bit)>>5)==13 && (1UL<<((bit)&31) & REQUIRED_MASK13)) || \ + (((bit)>>5)==14 && (1UL<<((bit)&31) & REQUIRED_MASK14)) ) #define DISABLED_MASK_BIT_SET(bit) \ - ( (((bit)>>5)==0 && (1UL<<((bit)&31) & DISABLED_MASK0)) || \ - (((bit)>>5)==1 && (1UL<<((bit)&31) & DISABLED_MASK1)) || \ - (((bit)>>5)==2 && (1UL<<((bit)&31) & DISABLED_MASK2)) || \ - (((bit)>>5)==3 && (1UL<<((bit)&31) & DISABLED_MASK3)) || \ - (((bit)>>5)==4 && (1UL<<((bit)&31) & DISABLED_MASK4)) || \ - (((bit)>>5)==5 && (1UL<<((bit)&31) & DISABLED_MASK5)) || \ - (((bit)>>5)==6 && (1UL<<((bit)&31) & DISABLED_MASK6)) || \ - (((bit)>>5)==7 && (1UL<<((bit)&31) & DISABLED_MASK7)) || \ - (((bit)>>5)==8 && (1UL<<((bit)&31) & DISABLED_MASK8)) || \ - (((bit)>>5)==9 && (1UL<<((bit)&31) & DISABLED_MASK9)) ) + ( (((bit)>>5)==0 && (1UL<<((bit)&31) & DISABLED_MASK0 )) || \ + (((bit)>>5)==1 && (1UL<<((bit)&31) & DISABLED_MASK1 )) || \ + (((bit)>>5)==2 && (1UL<<((bit)&31) & DISABLED_MASK2 )) || \ + (((bit)>>5)==3 && (1UL<<((bit)&31) & DISABLED_MASK3 )) || \ + (((bit)>>5)==4 && (1UL<<((bit)&31) & DISABLED_MASK4 )) || \ + (((bit)>>5)==5 && (1UL<<((bit)&31) & DISABLED_MASK5 )) || \ + (((bit)>>5)==6 && (1UL<<((bit)&31) & DISABLED_MASK6 )) || \ + (((bit)>>5)==7 && (1UL<<((bit)&31) & DISABLED_MASK7 )) || \ + (((bit)>>5)==8 && (1UL<<((bit)&31) & DISABLED_MASK8 )) || \ + (((bit)>>5)==9 && (1UL<<((bit)&31) & DISABLED_MASK9 )) || \ + (((bit)>>5)==10 && (1UL<<((bit)&31) & DISABLED_MASK10)) || \ + (((bit)>>5)==11 && (1UL<<((bit)&31) & DISABLED_MASK11)) || \ + (((bit)>>5)==12 && (1UL<<((bit)&31) & DISABLED_MASK12)) || \ + (((bit)>>5)==13 && (1UL<<((bit)&31) & DISABLED_MASK13)) || \ + (((bit)>>5)==14 && (1UL<<((bit)&31) & DISABLED_MASK14)) ) #define cpu_has(c, bit) \ (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \ diff -puN arch/x86/include/asm/disabled-features.h~pkeys-01-cpuid arch/x86/include/asm/disabled-features.h --- a/arch/x86/include/asm/disabled-features.h~pkeys-01-cpuid 2016-01-06 15:50:04.311097422 -0800 +++ b/arch/x86/include/asm/disabled-features.h 2016-01-06 15:50:04.318097738 -0800 @@ -28,6 +28,14 @@ # define DISABLE_CENTAUR_MCR 0 #endif /* CONFIG_X86_64 */ +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +# define DISABLE_PKU (1<<(X86_FEATURE_PKU)) +# define DISABLE_OSPKE (1<<(X86_FEATURE_OSPKE)) +#else +# define DISABLE_PKU 0 +# define DISABLE_OSPKE 0 +#endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */ + /* * Make sure to add features to the correct mask */ @@ -41,5 +49,10 @@ #define DISABLED_MASK7 0 #define DISABLED_MASK8 0 #define DISABLED_MASK9 (DISABLE_MPX) +#define DISABLED_MASK10 0 +#define DISABLED_MASK11 0 +#define DISABLED_MASK12 0 +#define DISABLED_MASK13 0 +#define DISABLED_MASK14 (DISABLE_PKU|DISABLE_OSPKE) #endif /* _ASM_X86_DISABLED_FEATURES_H */ diff -puN arch/x86/include/asm/required-features.h~pkeys-01-cpuid arch/x86/include/asm/required-features.h --- a/arch/x86/include/asm/required-features.h~pkeys-01-cpuid 2016-01-06 15:50:04.313097512 -0800 +++ b/arch/x86/include/asm/required-features.h 2016-01-06 15:50:04.318097738 -0800 @@ -92,5 +92,10 @@ #define REQUIRED_MASK7 0 #define REQUIRED_MASK8 0 #define REQUIRED_MASK9 0 +#define REQUIRED_MASK10 0 +#define REQUIRED_MASK11 0 +#define REQUIRED_MASK12 0 +#define REQUIRED_MASK13 0 +#define REQUIRED_MASK14 0 #endif /* _ASM_X86_REQUIRED_FEATURES_H */ diff -puN arch/x86/kernel/cpu/common.c~pkeys-01-cpuid arch/x86/kernel/cpu/common.c --- a/arch/x86/kernel/cpu/common.c~pkeys-01-cpuid 2016-01-06 15:50:04.314097557 -0800 +++ b/arch/x86/kernel/cpu/common.c 2016-01-06 15:50:04.319097783 -0800 @@ -619,6 +619,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c) cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx); c->x86_capability[9] = ebx; + c->x86_capability[14] = ecx; } /* Extended state features: level 0x0000000d */ _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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