[PATCH 3.16 036/131] x86/cpufeatures: Add FEATURE_ZEN

[Ben Hutchings]

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

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

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit d1035d971829dcf80e8686ccde26f94b0a069472 upstream.

Add a ZEN feature bit so family-dependent static_cpu_has() optimizations
can be built for ZEN.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16:
 - Use the next available bit number in CPU feature word 7
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/cpufeature.h | 1 +
 arch/x86/kernel/cpu/amd.c         | 1 +
 2 files changed, 2 insertions(+)

--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -198,6 +198,7 @@
 #define X86_FEATURE_STIBP	(7*32+18) /* Single Thread Indirect Branch Predictors */
 #define X86_FEATURE_MSR_SPEC_CTRL (7*32+19) /* "" MSR SPEC_CTRL is implemented */
 #define X86_FEATURE_SSBD	(7*32+20) /* Speculative Store Bypass Disable */
+#define X86_FEATURE_ZEN		(7*32+21) /* "" CPU is AMD family 0x17 (Zen) */
 
 #define X86_FEATURE_RETPOLINE	(7*32+29) /* "" Generic Retpoline mitigation for Spectre variant 2 */
 #define X86_FEATURE_RETPOLINE_AMD (7*32+30) /* "" AMD Retpoline mitigation for Spectre variant 2 */
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -556,6 +556,7 @@ static void init_amd_ln(struct cpuinfo_x
 
 static void init_amd_zn(struct cpuinfo_x86 *c)
 {
+	set_cpu_cap(c, X86_FEATURE_ZEN);
 	/*
 	 * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects
 	 * all up to and including B1.