[tip:mm/pkeys] x86/cpufeature, x86/mm/pkeys: Add protection keys related CPUID definitions

From: tip-bot for Dave Hansen
Date: Thu Feb 18 2016 - 15:18:26 EST

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Commit-ID: dfb4a70f20c5b3880da56ee4c9484bdb4e8f1e65
Gitweb: http://git.kernel.org/tip/dfb4a70f20c5b3880da56ee4c9484bdb4e8f1e65
Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 12 Feb 2016 13:02:01 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 16 Feb 2016 10:11:13 +0100

x86/cpufeature, x86/mm/pkeys: Add protection keys related CPUID definitions

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>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Link: http://lkml.kernel.org/r/20160212210201.7714C250@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/cpufeature.h | 59 +++++++++++++++++++++-----------
arch/x86/include/asm/cpufeatures.h | 2 +-
arch/x86/include/asm/disabled-features.h | 15 ++++++++
arch/x86/include/asm/required-features.h | 7 ++++
arch/x86/kernel/cpu/common.c | 1 +
5 files changed, 63 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 68e4e82..50e292a 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -26,6 +26,7 @@ enum cpuid_leafs
CPUID_8000_0008_EBX,
CPUID_6_EAX,
CPUID_8000_000A_EDX,
+ CPUID_7_ECX,
};

#ifdef CONFIG_X86_FEATURE_NAMES
@@ -48,28 +49,42 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
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)==13 && (1UL<<((bit)&31) & REQUIRED_MASK14)) || \
+ (((bit)>>5)==13 && (1UL<<((bit)&31) & REQUIRED_MASK15)) || \
+ (((bit)>>5)==14 && (1UL<<((bit)&31) & REQUIRED_MASK16)) )

#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)==13 && (1UL<<((bit)&31) & DISABLED_MASK14)) || \
+ (((bit)>>5)==13 && (1UL<<((bit)&31) & DISABLED_MASK15)) || \
+ (((bit)>>5)==14 && (1UL<<((bit)&31) & DISABLED_MASK16)) )

#define cpu_has(c, bit) \
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
@@ -79,6 +94,10 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
x86_this_cpu_test_bit(bit, (unsigned long *)&cpu_info.x86_capability))

+/* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 16 */
+#define X86_FEATURE_PKU (16*32+ 3) /* Protection Keys for Userspace */
+#define X86_FEATURE_OSPKE (16*32+ 4) /* OS Protection Keys Enable */
+
/*
* This macro is for detection of features which need kernel
* infrastructure to be used. It may *not* directly test the CPU
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 0ceb6ad..cbb2c56 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -12,7 +12,7 @@
/*
* Defines x86 CPU feature bits
*/
-#define NCAPINTS 16 /* N 32-bit words worth of info */
+#define NCAPINTS 17 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */

/*
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index f226df0..39343be 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -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 +49,12 @@
#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 0
+#define DISABLED_MASK15 0
+#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE)

#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 5c6e4fb..4916144 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -92,5 +92,12 @@
#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
+#define REQUIRED_MASK15 0
+#define REQUIRED_MASK16 0

#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index f4bb2c4..a719ad7 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -627,6 +627,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_7_0_EBX] = ebx;

c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006);
+ c->x86_capability[CPUID_7_ECX] = ecx;
}

/* Extended state features: level 0x0000000d */

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