linux-kernel - [PATCH 08/13] x86/CPU/AMD: Move the DIV0 bug detection to the Zen1 init function

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Message-ID: <20231120104152.13740-9-bp@alien8.de>
Date:   Mon, 20 Nov 2023 11:41:47 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 08/13] x86/CPU/AMD: Move the DIV0 bug detection to the Zen1 init function

From: "Borislav Petkov (AMD)" <bp@...en8.de>

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
---
 arch/x86/kernel/cpu/amd.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7cbb108afaf4..43d6a6da7591 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -70,10 +70,6 @@ static const int amd_erratum_383[] =
 static const int amd_erratum_1054[] =
 	AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x17, 0, 0, 0x2f, 0xf));
 
-static const int amd_div0[] =
-	AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x17, 0x00, 0x0, 0x2f, 0xf),
-			   AMD_MODEL_RANGE(0x17, 0x50, 0x0, 0x5f, 0xf));
-
 static const int amd_erratum_1485[] =
 	AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x19, 0x10, 0x0, 0x1f, 0xf),
 			   AMD_MODEL_RANGE(0x19, 0x60, 0x0, 0xaf, 0xf));
@@ -1031,6 +1027,8 @@ static void init_amd_zen(struct cpuinfo_x86 *c)
 			set_cpu_cap(c, X86_FEATURE_CPB);
 	}
 
+	pr_notice_once("AMD Zen1 DIV0 bug detected. Disable SMT for full protection.\n");
+	setup_force_cpu_bug(X86_BUG_DIV0);
 }
 
 static bool cpu_has_zenbleed_microcode(void)
@@ -1219,11 +1217,6 @@ static void init_amd(struct cpuinfo_x86 *c)
 	    cpu_has(c, X86_FEATURE_AUTOIBRS))
 		WARN_ON_ONCE(msr_set_bit(MSR_EFER, _EFER_AUTOIBRS));
 
-	if (cpu_has_amd_erratum(c, amd_div0)) {
-		pr_notice_once("AMD Zen1 DIV0 bug detected. Disable SMT for full protection.\n");
-		setup_force_cpu_bug(X86_BUG_DIV0);
-	}
-
 	if (!cpu_has(c, X86_FEATURE_HYPERVISOR) &&
 	     cpu_has_amd_erratum(c, amd_erratum_1485))
 		msr_set_bit(MSR_ZEN4_BP_CFG, MSR_ZEN4_BP_CFG_SHARED_BTB_FIX_BIT);
-- 
2.42.0.rc0.25.ga82fb66fed25