x86/mce: Add Skylake quirk for patrol scrub reported errors

The patrol scrubber in Skylake and Cascade Lake systems can be configured
to report uncorrected errors using a special signature in the machine
check bank and to signal using CMCI instead of machine check.

Update the severity calculation mechanism to allow specifying the model,
minimum stepping and range of machine check bank numbers.

Add a new rule to detect the special signature (on model 0x55, stepping
>=4 in any of the memory controller banks).

 [ bp: Rewrite it.
   aegl: Productize it. ]
Suggested-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200930021313.31810-2-tony.luck@intel.com

arch/x86/kernel/cpu/mce/severity.c

@@ -9,9 +9,11 @@
 #include <linux/seq_file.h>
 #include <linux/init.h>
 #include <linux/debugfs.h>
-#include <asm/mce.h>
 #include <linux/uaccess.h>
 
+#include <asm/mce.h>
+#include <asm/intel-family.h>
+
 #include "internal.h"
 
 /*
@@ -40,9 +42,14 @@ static struct severity {
 	unsigned char context;
 	unsigned char excp;
 	unsigned char covered;
+	unsigned char cpu_model;
+	unsigned char cpu_minstepping;
+	unsigned char bank_lo, bank_hi;
 	char *msg;
 } severities[] = {
 #define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
+#define BANK_RANGE(l, h) .bank_lo = l, .bank_hi = h
+#define MODEL_STEPPING(m, s) .cpu_model = m, .cpu_minstepping = s
 #define  KERNEL		.context = IN_KERNEL
 #define  USER		.context = IN_USER
 #define  KERNEL_RECOV	.context = IN_KERNEL_RECOV
@@ -97,7 +104,6 @@ static struct severity {
 		KEEP, "Corrected error",
 		NOSER, BITCLR(MCI_STATUS_UC)
 		),
-
 	/*
 	 * known AO MCACODs reported via MCE or CMC:
 	 *
@@ -113,6 +119,18 @@ static struct severity {
 		AO, "Action optional: last level cache writeback error",
 		SER, MASK(MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB)
 		),
+	/*
+	 * Quirk for Skylake/Cascade Lake. Patrol scrubber may be configured
+	 * to report uncorrected errors using CMCI with a special signature.
+	 * UC=0, MSCOD=0x0010, MCACOD=binary(000X 0000 1100 XXXX) reported
+	 * in one of the memory controller banks.
+	 * Set severity to "AO" for same action as normal patrol scrub error.
+	 */
+	MCESEV(
+		AO, "Uncorrected Patrol Scrub Error",
+		SER, MASK(MCI_STATUS_UC|MCI_ADDR|0xffffeff0, MCI_ADDR|0x001000c0),
+		MODEL_STEPPING(INTEL_FAM6_SKYLAKE_X, 4), BANK_RANGE(13, 18)
+	),
 
 	/* ignore OVER for UCNA */
 	MCESEV(
@@ -324,6 +342,12 @@ static int mce_severity_intel(struct mce *m, int tolerant, char **msg, bool is_e
 			continue;
 		if (s->excp && excp != s->excp)
 			continue;
+		if (s->cpu_model && boot_cpu_data.x86_model != s->cpu_model)
+			continue;
+		if (s->cpu_minstepping && boot_cpu_data.x86_stepping < s->cpu_minstepping)
+			continue;
+		if (s->bank_lo && (m->bank < s->bank_lo || m->bank > s->bank_hi))
+			continue;
 		if (msg)
 			*msg = s->msg;
 		s->covered = 1;