On Fri, 2018-09-28 at 18:51 +0200, Borislav Petkov wrote:

On Fri, Sep 21, 2018 at 08:03:25AM -0700, Yu-cheng Yu wrote:

quoted

Add CPUIDs for Control-flow Enforcement Technology (CET).

CPUID.(EAX=7,ECX=0):ECX[bit 7] Shadow stack
CPUID.(EAX=7,ECX=0):EDX[bit 20] Indirect branch tracking

Signed-off-by: Yu-cheng Yu <redacted>
---
 arch/x86/include/asm/cpufeatures.h | 2 ++
 arch/x86/kernel/cpu/scattered.c    | 1 +
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h

b/arch/x86/include/asm/cpufeatures.h
index 89a048c2faec..fa69651a017e 100644

--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h

@@ -221,6 +221,7 @@
 #define X86_FEATURE_ZEN			( 7*32+28) /* "" CPU is AMD

family 0x17 (Zen) */
 #define X86_FEATURE_L1TF_PTEINV		( 7*32+29) /* "" L1TF
workaround PTE inversion */
 #define X86_FEATURE_IBRS_ENHANCED	( 7*32+30) /* Enhanced IBRS */
+#define X86_FEATURE_IBT			( 7*32+31) /* Indirect
Branch Tracking */
 
 /* Virtualization flags: Linux defined, word 8 */
 #define X86_FEATURE_TPR_SHADOW		( 8*32+ 0) /* Intel TPR
Shadow */

@@ -321,6 +322,7 @@
 #define X86_FEATURE_PKU			(16*32+ 3) /* Protection

Keys for Userspace */
 #define X86_FEATURE_OSPKE		(16*32+ 4) /* OS Protection Keys
Enable */
 #define X86_FEATURE_AVX512_VBMI2	(16*32+ 6) /* Additional AVX512
Vector Bit Manipulation Instructions */
+#define X86_FEATURE_SHSTK		(16*32+ 7) /* Shadow Stack */
 #define X86_FEATURE_GFNI		(16*32+ 8) /* Galois Field New
Instructions */
 #define X86_FEATURE_VAES		(16*32+ 9) /* Vector AES */
 #define X86_FEATURE_VPCLMULQDQ		(16*32+10) /* Carry-Less
Multiplication Double Quadword */

diff --git a/arch/x86/kernel/cpu/scattered.c

b/arch/x86/kernel/cpu/scattered.c
index 772c219b6889..63cbb4d9938e 100644

--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c

@@ -21,6 +21,7 @@ struct cpuid_bit {
 static const struct cpuid_bit cpuid_bits[] = {
 	{ X86_FEATURE_APERFMPERF,       CPUID_ECX,  0, 0x00000006, 0 },
 	{ X86_FEATURE_EPB,		CPUID_ECX,  3, 0x00000006, 0 },
+	{ X86_FEATURE_IBT,		CPUID_EDX, 20, 0x00000007, 0},

If you haven't noticed, there's already a separate leaf:

/* Intel-defined CPU features, CPUID level 0x00000007:0 (EDX), word 18 */

in arch/x86/include/asm/cpufeatures.h

I will change to that one.  Thanks!

Yu-cheng