This patch disables GartTlbWlk errors on AMD Fam10h CPUs if
the BIOS forgets to do is (or is just too old). Letting
these errors enabled can cause a sync-flood on the CPU
causing a reboot.
This patch is the fix for
https://bugzilla.kernel.org/show_bug.cgi?id=33012
on my machine.
Signed-off-by: Joerg Roedel <joerg.roedel at amd.com>
---
arch/x86/include/asm/msr-index.h | 4 ++++
arch/x86/kernel/cpu/amd.c | 19 +++++++++++++++++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index fd5a1f3..3cce714 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -96,11 +96,15 @@
#define MSR_IA32_MC0_ADDR 0x00000402
#define MSR_IA32_MC0_MISC 0x00000403
+#define MSR_AMD64_MC0_MASK 0xc0010044
+
#define MSR_IA32_MCx_CTL(x) (MSR_IA32_MC0_CTL + 4*(x))
#define MSR_IA32_MCx_STATUS(x) (MSR_IA32_MC0_STATUS + 4*(x))
#define MSR_IA32_MCx_ADDR(x) (MSR_IA32_MC0_ADDR + 4*(x))
#define MSR_IA32_MCx_MISC(x) (MSR_IA32_MC0_MISC + 4*(x))
+#define MSR_AMD64_MCx_MASK(x) (MSR_AMD64_MC0_MASK + (x))
+
/* These are consecutive and not in the normal 4er MCE bank block */
#define MSR_IA32_MC0_CTL2 0x00000280
#define MSR_IA32_MCx_CTL2(x) (MSR_IA32_MC0_CTL2 + (x))
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 3ecece0..3532d3b 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -615,6 +615,25 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
/* As a rule processors have APIC timer running in deep C states */
if (c->x86 >= 0xf && !cpu_has_amd_erratum(amd_erratum_400))
set_cpu_cap(c, X86_FEATURE_ARAT);
+
+ /*
+ * Disable GART TLB Walk Errors on Fam10h. We do this here
+ * because this is always needed when GART is enabled, even in a
+ * kernel which has no MCE support built in.
+ */
+ if (c->x86 == 0x10) {
+ /*
+ * BIOS should disable GartTlbWlk Errors themself. If
+ * it doesn't do it here as suggested by the BKDG.
+ *
+ * Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=33012
+ */
+ u64 mask;
+
+ rdmsrl(MSR_AMD64_MCx_MASK(4), mask);
+ mask |= (1 << 10);
+ wrmsrl(MSR_AMD64_MCx_MASK(4), mask);
+ }
}
#ifdef CONFIG_X86_32
--
1.7.1
