powerpc/book3s: Flush SLB/TLBs if we get SLB/TLB machine check errors on power8.

This patch handles the memory errors on power8. If we get a machine check
exception due to SLB or TLB errors, then flush SLBs/TLBs and reload SLBs to
recover.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Author: maheshsal

arch/powerpc/include/asm/mce.h

@@ -64,4 +64,7 @@
 					 P7_DSISR_MC_SLB_MULTIHIT | \
 					 P7_DSISR_MC_SLB_MULTIHIT_PARITY)
 
+#define P8_DSISR_MC_SLB_ERRORS		(P7_DSISR_MC_SLB_ERRORS | \
+					 P8_DSISR_MC_ERAT_MULTIHIT_SEC)
+
 #endif /* __ASM_PPC64_MCE_H__ */

arch/powerpc/kernel/cputable.c

@@ -74,6 +74,7 @@ extern void __restore_cpu_a2(void);
 extern void __flush_tlb_power7(unsigned long inval_selector);
 extern void __flush_tlb_power8(unsigned long inval_selector);
 extern long __machine_check_early_realmode_p7(struct pt_regs *regs);
+extern long __machine_check_early_realmode_p8(struct pt_regs *regs);
 #endif /* CONFIG_PPC64 */
 #if defined(CONFIG_E500)
 extern void __setup_cpu_e5500(unsigned long offset, struct cpu_spec* spec);
@@ -462,6 +463,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.cpu_setup		= __setup_cpu_power8,
 		.cpu_restore		= __restore_cpu_power8,
 		.flush_tlb		= __flush_tlb_power8,
+		.machine_check_early	= __machine_check_early_realmode_p8,
 		.platform		= "power8",
 	},
 	{	/* Power7 */
@@ -521,6 +523,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.cpu_setup		= __setup_cpu_power8,
 		.cpu_restore		= __restore_cpu_power8,
 		.flush_tlb		= __flush_tlb_power8,
+		.machine_check_early	= __machine_check_early_realmode_p8,
 		.platform		= "power8",
 	},
 	{	/* Power8 */
@@ -540,6 +543,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
 		.cpu_setup		= __setup_cpu_power8,
 		.cpu_restore		= __restore_cpu_power8,
 		.flush_tlb		= __flush_tlb_power8,
+		.machine_check_early	= __machine_check_early_realmode_p8,
 		.platform		= "power8",
 	},
 	{	/* Cell Broadband Engine */

arch/powerpc/kernel/mce_power.c

@@ -148,3 +148,37 @@ long __machine_check_early_realmode_p7(struct pt_regs *regs)
 	/* TODO: Decode machine check reason. */
 	return handled;
 }
+
+static long mce_handle_ierror_p8(uint64_t srr1)
+{
+	long handled = 0;
+
+	handled = mce_handle_common_ierror(srr1);
+
+	if (P7_SRR1_MC_IFETCH(srr1) == P8_SRR1_MC_IFETCH_ERAT_MULTIHIT) {
+		flush_and_reload_slb();
+		handled = 1;
+	}
+	return handled;
+}
+
+static long mce_handle_derror_p8(uint64_t dsisr)
+{
+	return mce_handle_derror(dsisr, P8_DSISR_MC_SLB_ERRORS);
+}
+
+long __machine_check_early_realmode_p8(struct pt_regs *regs)
+{
+	uint64_t srr1;
+	long handled = 1;
+
+	srr1 = regs->msr;
+
+	if (P7_SRR1_MC_LOADSTORE(srr1))
+		handled = mce_handle_derror_p8(regs->dsisr);
+	else
+		handled = mce_handle_ierror_p8(srr1);
+
+	/* TODO: Decode machine check reason. */
+	return handled;
+}