linux-kernel - [PATCH 3.16 041/410] x86/cpufeatures: Add Intel feature bits for Speculation Control

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Message-ID: <lsq.1528380321.720406059@decadent.org.uk>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, gnomes@...rguk.ukuu.org.uk,
        arjan@...ux.intel.com, karahmed@...zon.de,
        torvalds@...ux-foundation.org,
        "Thomas Gleixner" <tglx@...utronix.de>, dave.hansen@...el.com,
        ak@...ux.intel.com, gregkh@...ux-foundation.org,
        "David Woodhouse" <dwmw@...zon.co.uk>, ashok.raj@...el.com,
        bp@...en8.de, "Borislav Petkov" <bp@...e.de>, peterz@...radead.org,
        pbonzini@...hat.com, tim.c.chen@...ux.intel.com,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>
Subject: [PATCH 3.16 041/410] x86/cpufeatures: Add Intel feature bits for
 Speculation Control

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: David Woodhouse <dwmw@...zon.co.uk>

commit fc67dd70adb711a45d2ef34e12d1a8be75edde61 upstream.

Add three feature bits exposed by new microcode on Intel CPUs for
speculation control.

Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Reviewed-by: Borislav Petkov <bp@...e.de>
Cc: gnomes@...rguk.ukuu.org.uk
Cc: ak@...ux.intel.com
Cc: ashok.raj@...el.com
Cc: dave.hansen@...el.com
Cc: karahmed@...zon.de
Cc: arjan@...ux.intel.com
Cc: torvalds@...ux-foundation.org
Cc: peterz@...radead.org
Cc: bp@...en8.de
Cc: pbonzini@...hat.com
Cc: tim.c.chen@...ux.intel.com
Cc: gregkh@...ux-foundation.org
Link: https://lkml.kernel.org/r/1516896855-7642-3-git-send-email-dwmw@amazon.co.uk
Signed-off-by: David Woodhouse <dwmw@...zon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
[bwh: Backported to 3.16: This CPUID word wasn't used at all yet, so
 add it as feature word 10]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/include/asm/cpufeature.h | 7 ++++++-
 arch/x86/kernel/cpu/common.c      | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -8,7 +8,7 @@
 #include <asm/required-features.h>
 #endif
 
-#define NCAPINTS	10	/* N 32-bit words worth of info */
+#define NCAPINTS	11	/* N 32-bit words worth of info */
 #define NBUGINTS	1	/* N 32-bit bug flags */
 
 /*
@@ -234,6 +234,11 @@
 #define X86_FEATURE_AVX512ER	(9*32+27) /* AVX-512 Exponential and Reciprocal */
 #define X86_FEATURE_AVX512CD	(9*32+28) /* AVX-512 Conflict Detection */
 
+/* Intel-defined CPU features, CPUID level 0x00000007:0 (EDX), word 10 */
+#define X86_FEATURE_SPEC_CTRL		(10*32+26) /* Speculation Control (IBRS + IBPB) */
+#define X86_FEATURE_STIBP		(10*32+27) /* Single Thread Indirect Branch Predictors */
+#define X86_FEATURE_ARCH_CAPABILITIES	(10*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
+
 /*
  * BUG word(s)
  */
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -701,6 +701,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
 		cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
 
 		c->x86_capability[9] = ebx;
+		c->x86_capability[10] = edx;
 	}
 
 	/* AMD-defined flags: level 0x80000001 */