linux-kernel - [PATCH] x86/cpu/amd: Extend calling init_amd

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Date:   Wed, 11 Mar 2020 14:14:51 -0500
From:   Kim Phillips <kim.phillips@....com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, kim.phillips@....com
Cc:     "H. Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Frank van der Linden <fllinden@...zon.com>,
        Michael Petlan <mpetlan@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] x86/cpu/amd: Extend calling init_amd_zn() to Family 19h processors

Family 19h CPUs are Zen based and still share most architectural
features with Family 17h CPUs, and therefore still need to call
init_amd_zn() e.g., to set the RECLAIM_DISTANCE override.

init_amd_zn() also sets X86_FEATURE_ZEN, which today is only used
in amd_set_core_ssb_state(), which isn't called on some late
model Family 17h CPUs, nor on any Family 19h CPUs:
X86_FEATURE_AMD_SSBD replaces X86_FEATURE_LS_CFG_SSBD on those
later model CPUs, where the SSBD mitigation is done via the
SPEC_CTRL MSR instead of the LS_CFG MSR.

Family 19h CPUs also don't have the erratum where the CPB feature
bit isn't set, but that code can stay unchanged and run safely
on Family 19h.

Signed-off-by: Kim Phillips <kim.phillips@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Frank van der Linden <fllinden@...zon.com>
Cc: Michael Petlan <mpetlan@...hat.com>
Cc: x86@...nel.org
Cc: linux-kernel@...r.kernel.org
---
 arch/x86/include/asm/cpufeatures.h | 2 +-
 arch/x86/kernel/cpu/amd.c          | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index f3327cb56edf..f980efcacfeb 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -217,7 +217,7 @@
 #define X86_FEATURE_IBRS		( 7*32+25) /* Indirect Branch Restricted Speculation */
 #define X86_FEATURE_IBPB		( 7*32+26) /* Indirect Branch Prediction Barrier */
 #define X86_FEATURE_STIBP		( 7*32+27) /* Single Thread Indirect Branch Predictors */
-#define X86_FEATURE_ZEN			( 7*32+28) /* "" CPU is AMD family 0x17 (Zen) */
+#define X86_FEATURE_ZEN			( 7*32+28) /* "" CPU is AMD family 0x17 or above (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_MSR_IA32_FEAT_CTL	( 7*32+31) /* "" MSR IA32_FEAT_CTL configured */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 1f875fbe1384..af952d7ed2fc 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -926,7 +926,8 @@ static void init_amd(struct cpuinfo_x86 *c)
 	case 0x12: init_amd_ln(c); break;
 	case 0x15: init_amd_bd(c); break;
 	case 0x16: init_amd_jg(c); break;
-	case 0x17: init_amd_zn(c); break;
+	case 0x17: fallthrough;
+	case 0x19: init_amd_zn(c); break;
 	}
 
 	/*
-- 
2.25.1