RAS: add the support for handling UCNA/DEFERRED error

index 276392f..51b26e89 100644
@@ -34,6 +34,10 @@
 #define MCI_STATUS_S	 (1ULL<<56)  /* Signaled machine check */
 #define MCI_STATUS_AR	 (1ULL<<55)  /* Action required */
 
+/* AMD-specific bits */
+#define MCI_STATUS_DEFERRED	(1ULL<<44)  /* declare an uncorrected error */
+#define MCI_STATUS_POISON	(1ULL<<43)  /* access poisonous data */
+
 /*
  * Note that the full MCACOD field of IA32_MCi_STATUS MSR is
  * bits 15:0.  But bit 12 is the 'F' bit, defined for corrected

index 09edd0b..10b4690 100644
@@ -3,6 +3,8 @@
 
 enum severity_level {
 	MCE_NO_SEVERITY,
+	MCE_DEFERRED_SEVERITY,
+	MCE_UCNA_SEVERITY = MCE_DEFERRED_SEVERITY,
 	MCE_KEEP_SEVERITY,
 	MCE_SOME_SEVERITY,
 	MCE_AO_SEVERITY,

@@ -21,7 +23,7 @@ struct mce_bank {
 	char			attrname[ATTR_LEN];	/* attribute name */
 };
 
-int mce_severity(struct mce *a, int tolerant, char **msg);
+int mce_severity(struct mce *a, int tolerant, char **msg, bool is_excp);
 struct dentry *mce_get_debugfs_dir(void);
 
 extern struct mce_bank *mce_banks;

index c370e1c..8bb4330 100644
@@ -31,6 +31,7 @@
 
 enum context { IN_KERNEL = 1, IN_USER = 2 };
 enum ser { SER_REQUIRED = 1, NO_SER = 2 };
+enum exception { EXCP_CONTEXT = 1, NO_EXCP = 2 };
 
 static struct severity {
 	u64 mask;

@@ -40,6 +41,7 @@ static struct severity {
 	unsigned char mcgres;
 	unsigned char ser;
 	unsigned char context;
+	unsigned char excp;
 	unsigned char covered;
 	char *msg;
 } severities[] = {

@@ -48,6 +50,8 @@ static struct severity {
 #define  USER		.context = IN_USER
 #define  SER		.ser = SER_REQUIRED
 #define  NOSER		.ser = NO_SER
+#define  EXCP		.excp = EXCP_CONTEXT
+#define  NOEXCP		.excp = NO_EXCP
 #define  BITCLR(x)	.mask = x, .result = 0
 #define  BITSET(x)	.mask = x, .result = x
 #define  MCGMASK(x, y)	.mcgmask = x, .mcgres = y

@@ -62,7 +66,7 @@ static struct severity {
 		),
 	MCESEV(
 		NO, "Not enabled",
-		BITCLR(MCI_STATUS_EN)
+		EXCP, BITCLR(MCI_STATUS_EN)
 		),
 	MCESEV(
 		PANIC, "Processor context corrupt",

@@ -71,16 +75,20 @@ static struct severity {
 	/* When MCIP is not set something is very confused */
 	MCESEV(
 		PANIC, "MCIP not set in MCA handler",
-		MCGMASK(MCG_STATUS_MCIP, 0)
+		EXCP, MCGMASK(MCG_STATUS_MCIP, 0)
 		),
 	/* Neither return not error IP -- no chance to recover -> PANIC */
 	MCESEV(
 		PANIC, "Neither restart nor error IP",
-		MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
+		EXCP, MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
 		),
 	MCESEV(
 		PANIC, "In kernel and no restart IP",
-		KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
+		EXCP, KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
+		),
+	MCESEV(
+		DEFERRED, "Deferred error",
+		NOSER, MASK(MCI_STATUS_UC|MCI_STATUS_DEFERRED|MCI_STATUS_POISON, MCI_STATUS_DEFERRED)
 		),
 	MCESEV(
 		KEEP, "Corrected error",

@@ -89,7 +97,7 @@ static struct severity {
 
 	/* ignore OVER for UCNA */
 	MCESEV(
-		KEEP, "Uncorrected no action required",
+		UCNA, "Uncorrected no action required",
 		SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
 		),
 	MCESEV(

@@ -178,8 +186,9 @@ static int error_context(struct mce *m)
 	return ((m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
 }
 
-int mce_severity(struct mce *m, int tolerant, char **msg)
+int mce_severity(struct mce *m, int tolerant, char **msg, bool is_excp)
 {
+	enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
 	enum context ctx = error_context(m);
 	struct severity *s;
 

@@ -194,6 +203,8 @@ int mce_severity(struct mce *m, int tolerant, char **msg)
 			continue;
 		if (s->context && ctx != s->context)
 			continue;
+		if (s->excp && excp != s->excp)
+			continue;
 		if (msg)
 			*msg = s->msg;
 		s->covered = 1;

index 61a9668ce..453e9bf 100644
@@ -668,7 +668,8 @@ static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
 			if (quirk_no_way_out)
 				quirk_no_way_out(i, m, regs);
 		}
-		if (mce_severity(m, mca_cfg.tolerant, msg) >= MCE_PANIC_SEVERITY)
+		if (mce_severity(m, mca_cfg.tolerant, msg, true) >=
+		    MCE_PANIC_SEVERITY)
 			ret = 1;
 	}
 	return ret;

@@ -754,7 +755,7 @@ static void mce_reign(void)
 	for_each_possible_cpu(cpu) {
 		int severity = mce_severity(&per_cpu(mces_seen, cpu),
 					    mca_cfg.tolerant,
-					    &nmsg);
+					    &nmsg, true);
 		if (severity > global_worst) {
 			msg = nmsg;
 			global_worst = severity;

@@ -1095,13 +1096,14 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 		 */
 		add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 
-		severity = mce_severity(&m, cfg->tolerant, NULL);
+		severity = mce_severity(&m, cfg->tolerant, NULL, true);
 
 		/*
-		 * When machine check was for corrected handler don't touch,
-		 * unless we're panicing.
+		 * When machine check was for corrected/deferred handler don't
+		 * touch, unless we're panicing.
 		 */
-		if (severity == MCE_KEEP_SEVERITY && !no_way_out)
+		if ((severity == MCE_KEEP_SEVERITY ||
+		     severity == MCE_UCNA_SEVERITY) && !no_way_out)
 			continue;
 		__set_bit(i, toclear);
 		if (severity == MCE_NO_SEVERITY) {

index 51b7e3a..c2359a1 100644
@@ -32,9 +32,6 @@
 #define R4(x)				(((x) >> 4) & 0xf)
 #define R4_MSG(x)			((R4(x) < 9) ?  rrrr_msgs[R4(x)] : "Wrong R4!")
 
-#define MCI_STATUS_DEFERRED		BIT_64(44)
-#define MCI_STATUS_POISON		BIT_64(43)
-
 extern const char * const pp_msgs[];
 
 enum tt_ids {

index 453e9bf..cfb16f6 100644
@@ -575,6 +575,37 @@ static void mce_read_aux(struct mce *m, int i)
 	}
 }
 
+static bool memory_error(struct mce *m)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	if (c->x86_vendor == X86_VENDOR_AMD) {
+		/*
+		 * coming soon
+		 */
+		return false;
+	} else if (c->x86_vendor == X86_VENDOR_INTEL) {
+		/*
+		 * Intel SDM Volume 3B - 15.9.2 Compound Error Codes
+		 *
+		 * Bit 7 of the MCACOD field of IA32_MCi_STATUS is used for
+		 * indicating a memory error. Bit 8 is used for indicating a
+		 * cache hierarchy error. The combination of bit 2 and bit 3
+		 * is used for indicating a `generic' cache hierarchy error
+		 * But we can't just blindly check the above bits, because if
+		 * bit 11 is set, then it is a bus/interconnect error - and
+		 * either way the above bits just gives more detail on what
+		 * bus/interconnect error happened. Note that bit 12 can be
+		 * ignored, as it's the "filter" bit.
+		 */
+		return (m->status & 0xef80) == BIT(7) ||
+		       (m->status & 0xef00) == BIT(8) ||
+		       (m->status & 0xeffc) == 0xc;
+	}
+
+	return false;
+}
+
 DEFINE_PER_CPU(unsigned, mce_poll_count);
 
 /*

@@ -595,6 +626,7 @@ DEFINE_PER_CPU(unsigned, mce_poll_count);
 void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 {
 	struct mce m;
+	int severity;
 	int i;
 
 	this_cpu_inc(mce_poll_count);

@@ -630,6 +662,20 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
 
 		if (!(flags & MCP_TIMESTAMP))
 			m.tsc = 0;
+
+		severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
+
+		/*
+		 * In the cases where we don't have a valid address after all,
+		 * do not add it into the ring buffer.
+		 */
+		if (severity == MCE_DEFERRED_SEVERITY && memory_error(&m)) {
+			if (m.status & MCI_STATUS_ADDRV) {
+				mce_ring_add(m.addr >> PAGE_SHIFT);
+				mce_schedule_work();
+			}
+		}
+
 		/*
 		 * Don't get the IP here because it's unlikely to
 		 * have anything to do with the actual error location.