[PATCH] x86/mce: Init some CPU features early

[Yazen Ghannam]

When we poll the MCA banks in __mcheck_cpu_init_generic() for leftover
errors logged during boot or from the previous boot, we need to have
detected CPU features sufficiently so that the reading out and handling
of those early errors is done correctly.

If we don't do it, we may miss some information/get incomplete errors
logged. For example, on SMCA systems we will not log the MCA_IPID and
MCA_SYND registers and we won't mask MCA_ADDR appropriately.

For that, do a subset of the basic feature detection early while the
rest happens in its usual place in __mcheck_cpu_init_vendor().

Signed-off-by: Yazen Ghannam <Yazen.Ghannam@xxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1489599055-20756-1-git-send-email-Yazen.Ghannam@xxxxxxx
[ Massage commit message and simplify. ]
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
 arch/x86/kernel/cpu/mcheck/mce.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 177472ace838..5e365a2fabe5 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1702,30 +1702,35 @@ static int __mcheck_cpu_ancient_init(struct cpuinfo_x86 *c)
 	return 0;
 }
 
-static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
+/*
+ * Init basic CPU features needed for early decoding of MCEs.
+ */
+static void __mcheck_cpu_init_early(struct cpuinfo_x86 *c)
 {
-	switch (c->x86_vendor) {
-	case X86_VENDOR_INTEL:
-		mce_intel_feature_init(c);
-		mce_adjust_timer = cmci_intel_adjust_timer;
-		break;
-
-	case X86_VENDOR_AMD: {
+	if (c->x86_vendor == X86_VENDOR_AMD) {
 		mce_flags.overflow_recov = !!cpu_has(c, X86_FEATURE_OVERFLOW_RECOV);
 		mce_flags.succor	 = !!cpu_has(c, X86_FEATURE_SUCCOR);
 		mce_flags.smca		 = !!cpu_has(c, X86_FEATURE_SMCA);
 
-		/*
-		 * Install proper ops for Scalable MCA enabled processors
-		 */
 		if (mce_flags.smca) {
 			msr_ops.ctl	= smca_ctl_reg;
 			msr_ops.status	= smca_status_reg;
 			msr_ops.addr	= smca_addr_reg;
 			msr_ops.misc	= smca_misc_reg;
 		}
-		mce_amd_feature_init(c);
+	}
+}
 
+static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
+{
+	switch (c->x86_vendor) {
+	case X86_VENDOR_INTEL:
+		mce_intel_feature_init(c);
+		mce_adjust_timer = cmci_intel_adjust_timer;
+		break;
+
+	case X86_VENDOR_AMD: {
+		mce_amd_feature_init(c);
 		break;
 		}
 
@@ -1812,6 +1817,7 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
 
 	machine_check_vector = do_machine_check;
 
+	__mcheck_cpu_init_early(c);
 	__mcheck_cpu_init_generic();
 	__mcheck_cpu_init_vendor(c);
 	__mcheck_cpu_init_clear_banks();
-- 
2.11.0

-- 
Regards/Gruss,
    Boris.

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