x86/mce/AMD: Set MCAX Enable bit

Aravind Gopalakrishnan · Ingo Molnar · commit e6c8f1873be8 · 2016-02-01T10:53:59.000+01:00
It is required for the OS to acknowledge that it is using the MCAX register set and its associated fields by setting the 'McaXEnable' bit in each bank's MCi_CONFIG register. If it is not set, then all UC errors will cause a system panic. Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac <linux-edac@vger.kernel.org> Link: http://lkml.kernel.org/r/1453750913-4781-9-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
@@ -264,6 +264,10 @@
 #define MSR_IA32_MC0_CTL2		0x00000280
 #define MSR_IA32_MCx_CTL2(x)		(MSR_IA32_MC0_CTL2 + (x))
 
+/* 'SMCA': AMD64 Scalable MCA */
+#define MSR_AMD64_SMCA_MC0_CONFIG	0xc0002004
+#define MSR_AMD64_SMCA_MCx_CONFIG(x)	(MSR_AMD64_SMCA_MC0_CONFIG + 0x10*(x))
+
 #define MSR_P6_PERFCTR0			0x000000c1
 #define MSR_P6_PERFCTR1			0x000000c2
 #define MSR_P6_EVNTSEL0			0x00000186
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -54,6 +54,14 @@
 /* Threshold LVT offset is at MSR0xC0000410[15:12] */
 #define SMCA_THR_LVT_OFF	0xF000
 
+/*
+ * OS is required to set the MCAX bit to acknowledge that it is now using the
+ * new MSR ranges and new registers under each bank. It also means that the OS
+ * will configure deferred errors in the new MCx_CONFIG register. If the bit is
+ * not set, uncorrectable errors will cause a system panic.
+ */
+#define SMCA_MCAX_EN_OFF	0x1
+
 static const char * const th_names[] = {
 	"load_store",
 	"insn_fetch",
@@ -292,6 +300,12 @@ prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr,
 
 	if (mce_flags.smca) {
 		u32 smca_low, smca_high;
+		u32 smca_addr = MSR_AMD64_SMCA_MCx_CONFIG(bank);
+
+		if (!rdmsr_safe(smca_addr, &smca_low, &smca_high)) {
+			smca_high |= SMCA_MCAX_EN_OFF;
+			wrmsr(smca_addr, smca_low, smca_high);
+		}
 
 		/* Gather LVT offset for thresholding: */
 		if (rdmsr_safe(MSR_CU_DEF_ERR, &smca_low, &smca_high))
