Fix machine check recovery for instruction fault on Sandy Bridge

index 441520e..a3ac52b 100644
@@ -33,6 +33,14 @@
 #define MCI_STATUS_PCC   (1ULL<<57)  /* processor context corrupt */
 #define MCI_STATUS_S	 (1ULL<<56)  /* Signaled machine check */
 #define MCI_STATUS_AR	 (1ULL<<55)  /* Action required */
+#define MCACOD		  0xffff     /* MCA Error Code */
+
+/* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
+#define MCACOD_SCRUB	0x00C0	/* 0xC0-0xCF Memory Scrubbing */
+#define MCACOD_SCRUBMSK	0xfff0
+#define MCACOD_L3WB	0x017A	/* L3 Explicit Writeback */
+#define MCACOD_DATA	0x0134	/* Data Load */
+#define MCACOD_INSTR	0x0150	/* Instruction Fetch */
 
 /* MCi_MISC register defines */
 #define MCI_MISC_ADDR_LSB(m)	((m) & 0x3f)

index 413c2ce..1301762 100644
@@ -55,13 +55,6 @@ static struct severity {
 #define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
 #define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
 #define	MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
-#define MCACOD 0xffff
-/* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
-#define MCACOD_SCRUB	0x00C0	/* 0xC0-0xCF Memory Scrubbing */
-#define MCACOD_SCRUBMSK	0xfff0
-#define MCACOD_L3WB	0x017A	/* L3 Explicit Writeback */
-#define MCACOD_DATA	0x0134	/* Data Load */
-#define MCACOD_INSTR	0x0150	/* Instruction Fetch */
 
 	MCESEV(
 		NO, "Invalid",

index 441520e..a3ac52b 100644
@@ -33,6 +33,14 @@
 #define MCI_STATUS_PCC   (1ULL<<57)  /* processor context corrupt */
 #define MCI_STATUS_S	 (1ULL<<56)  /* Signaled machine check */
 #define MCI_STATUS_AR	 (1ULL<<55)  /* Action required */
+#define MCACOD		  0xffff     /* MCA Error Code */
+
+/* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
+#define MCACOD_SCRUB	0x00C0	/* 0xC0-0xCF Memory Scrubbing */
+#define MCACOD_SCRUBMSK	0xfff0
+#define MCACOD_L3WB	0x017A	/* L3 Explicit Writeback */
+#define MCACOD_DATA	0x0134	/* Data Load */
+#define MCACOD_INSTR	0x0150	/* Instruction Fetch */
 
 /* MCi_MISC register defines */
 #define MCI_MISC_ADDR_LSB(m)	((m) & 0x3f)

index 413c2ce..1301762 100644
@@ -55,13 +55,6 @@ static struct severity {
 #define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
 #define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
 #define	MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
-#define MCACOD 0xffff
-/* Architecturally defined codes from SDM Vol. 3B Chapter 15 */
-#define MCACOD_SCRUB	0x00C0	/* 0xC0-0xCF Memory Scrubbing */
-#define MCACOD_SCRUBMSK	0xfff0
-#define MCACOD_L3WB	0x017A	/* L3 Explicit Writeback */
-#define MCACOD_DATA	0x0134	/* Data Load */
-#define MCACOD_INSTR	0x0150	/* Instruction Fetch */
 
 	MCESEV(
 		NO, "Invalid",

index da27c5d..e65e738 100644
@@ -102,6 +102,8 @@ DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
 
 static DEFINE_PER_CPU(struct work_struct, mce_work);
 
+static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
+
 /*
  * CPU/chipset specific EDAC code can register a notifier call here to print
  * MCE errors in a human-readable form.

@@ -649,14 +651,18 @@ EXPORT_SYMBOL_GPL(machine_check_poll);
  * Do a quick check if any of the events requires a panic.
  * This decides if we keep the events around or clear them.
  */
-static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp)
+static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
+			  struct pt_regs *regs)
 {
 	int i, ret = 0;
 
 	for (i = 0; i < banks; i++) {
 		m->status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
-		if (m->status & MCI_STATUS_VAL)
+		if (m->status & MCI_STATUS_VAL) {
 			__set_bit(i, validp);
+			if (quirk_no_way_out)
+				quirk_no_way_out(i, m, regs);
+		}
 		if (mce_severity(m, tolerant, msg) >= MCE_PANIC_SEVERITY)
 			ret = 1;
 	}

@@ -1039,7 +1045,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 	*final = m;
 
 	memset(valid_banks, 0, sizeof(valid_banks));
-	no_way_out = mce_no_way_out(&m, &msg, valid_banks);
+	no_way_out = mce_no_way_out(&m, &msg, valid_banks, regs);
 
 	barrier();
 

@@ -1415,6 +1421,34 @@ static void __mcheck_cpu_init_generic(void)
 	}
 }
 
+/*
+ * During IFU recovery Sandy Bridge -EP4S processors set the RIPV and
+ * EIPV bits in MCG_STATUS to zero on the affected logical processor (SDM
+ * Vol 3B Table 15-20). But this confuses both the code that determines
+ * whether the machine check occurred in kernel or user mode, and also
+ * the severity assessment code. Pretend that EIPV was set, and take the
+ * ip/cs values from the pt_regs that mce_gather_info() ignored earlier.
+ */
+static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs)
+{
+	if (bank != 0)
+		return;
+	if ((m->mcgstatus & (MCG_STATUS_EIPV|MCG_STATUS_RIPV)) != 0)
+		return;
+	if ((m->status & (MCI_STATUS_OVER|MCI_STATUS_UC|
+		          MCI_STATUS_EN|MCI_STATUS_MISCV|MCI_STATUS_ADDRV|
+			  MCI_STATUS_PCC|MCI_STATUS_S|MCI_STATUS_AR|
+			  MCACOD)) !=
+			 (MCI_STATUS_UC|MCI_STATUS_EN|
+			  MCI_STATUS_MISCV|MCI_STATUS_ADDRV|MCI_STATUS_S|
+			  MCI_STATUS_AR|MCACOD_INSTR))
+		return;
+
+	m->mcgstatus |= MCG_STATUS_EIPV;
+	m->ip = regs->ip;
+	m->cs = regs->cs;
+}
+
 /* Add per CPU specific workarounds here */
 static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
 {

@@ -1512,6 +1546,9 @@ static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
 		 */
 		if (c->x86 == 6 && c->x86_model <= 13 && mce_bootlog < 0)
 			mce_bootlog = 0;
+
+		if (c->x86 == 6 && c->x86_model == 45)
+			quirk_no_way_out = quirk_sandybridge_ifu;
 	}
 	if (monarch_timeout < 0)
 		monarch_timeout = 0;

index 5a5a5dc..8cf60e2 100644
@@ -105,6 +105,8 @@ DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
 
 static DEFINE_PER_CPU(struct work_struct, mce_work);
 
+static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
+
 /*
  * CPU/chipset specific EDAC code can register a notifier call here to print
  * MCE errors in a human-readable form.

@@ -652,14 +654,18 @@ EXPORT_SYMBOL_GPL(machine_check_poll);
  * Do a quick check if any of the events requires a panic.
  * This decides if we keep the events around or clear them.
  */
-static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp)
+static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
+			  struct pt_regs *regs)
 {
 	int i, ret = 0;
 
 	for (i = 0; i < banks; i++) {
 		m->status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
-		if (m->status & MCI_STATUS_VAL)
+		if (m->status & MCI_STATUS_VAL) {
 			__set_bit(i, validp);
+			if (quirk_no_way_out)
+				quirk_no_way_out(i, m, regs);
+		}
 		if (mce_severity(m, tolerant, msg) >= MCE_PANIC_SEVERITY)
 			ret = 1;
 	}

@@ -1042,7 +1048,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 	*final = m;
 
 	memset(valid_banks, 0, sizeof(valid_banks));
-	no_way_out = mce_no_way_out(&m, &msg, valid_banks);
+	no_way_out = mce_no_way_out(&m, &msg, valid_banks, regs);
 
 	barrier();
 

@@ -1418,6 +1424,34 @@ static void __mcheck_cpu_init_generic(void)
 	}
 }
 
+/*
+ * During IFU recovery Sandy Bridge -EP4S processors set the RIPV and
+ * EIPV bits in MCG_STATUS to zero on the affected logical processor (SDM
+ * Vol 3B Table 15-20). But this confuses both the code that determines
+ * whether the machine check occurred in kernel or user mode, and also
+ * the severity assessment code. Pretend that EIPV was set, and take the
+ * ip/cs values from the pt_regs that mce_gather_info() ignored earlier.
+ */
+static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs)
+{
+	if (bank != 0)
+		return;
+	if ((m->mcgstatus & (MCG_STATUS_EIPV|MCG_STATUS_RIPV)) != 0)
+		return;
+	if ((m->status & (MCI_STATUS_OVER|MCI_STATUS_UC|
+		          MCI_STATUS_EN|MCI_STATUS_MISCV|MCI_STATUS_ADDRV|
+			  MCI_STATUS_PCC|MCI_STATUS_S|MCI_STATUS_AR|
+			  MCACOD)) !=
+			 (MCI_STATUS_UC|MCI_STATUS_EN|
+			  MCI_STATUS_MISCV|MCI_STATUS_ADDRV|MCI_STATUS_S|
+			  MCI_STATUS_AR|MCACOD_INSTR))
+		return;
+
+	m->mcgstatus |= MCG_STATUS_EIPV;
+	m->ip = regs->ip;
+	m->cs = regs->cs;
+}
+
 /* Add per CPU specific workarounds here */
 static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
 {

@@ -1515,6 +1549,9 @@ static int __cpuinit __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
 		 */
 		if (c->x86 == 6 && c->x86_model <= 13 && mce_bootlog < 0)
 			mce_bootlog = 0;
+
+		if (c->x86 == 6 && c->x86_model == 45)
+			quirk_no_way_out = quirk_sandybridge_ifu;
 	}
 	if (monarch_timeout < 0)
 		monarch_timeout = 0;