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

From: Borislav Petkov
Date: Mon Nov 20 2023 - 05:43:41 EST


From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
---
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