Revisit MCE handling for UE Errors

index 190d69a..75292c7 100644
@@ -210,6 +210,4 @@ extern void release_mce_event(void);
 extern void machine_check_queue_event(void);
 extern void machine_check_print_event_info(struct machine_check_event *evt,
 					   bool user_mode);
-extern uint64_t get_mce_fault_addr(struct machine_check_event *evt);
-
 #endif /* __ASM_PPC64_MCE_H__ */

index 9b2ea7e..e254399 100644
@@ -411,45 +411,6 @@ void machine_check_print_event_info(struct machine_check_event *evt,
 }
 EXPORT_SYMBOL_GPL(machine_check_print_event_info);
 
-uint64_t get_mce_fault_addr(struct machine_check_event *evt)
-{
-	switch (evt->error_type) {
-	case MCE_ERROR_TYPE_UE:
-		if (evt->u.ue_error.effective_address_provided)
-			return evt->u.ue_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_SLB:
-		if (evt->u.slb_error.effective_address_provided)
-			return evt->u.slb_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_ERAT:
-		if (evt->u.erat_error.effective_address_provided)
-			return evt->u.erat_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_TLB:
-		if (evt->u.tlb_error.effective_address_provided)
-			return evt->u.tlb_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_USER:
-		if (evt->u.user_error.effective_address_provided)
-			return evt->u.user_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_RA:
-		if (evt->u.ra_error.effective_address_provided)
-			return evt->u.ra_error.effective_address;
-		break;
-	case MCE_ERROR_TYPE_LINK:
-		if (evt->u.link_error.effective_address_provided)
-			return evt->u.link_error.effective_address;
-		break;
-	default:
-	case MCE_ERROR_TYPE_UNKNOWN:
-		break;
-	}
-	return 0;
-}
-EXPORT_SYMBOL(get_mce_fault_addr);
-
 /*
  * This function is called in real mode. Strictly no printk's please.
  *

index e254399..fef1408 100644
@@ -340,7 +340,7 @@ void machine_check_print_event_info(struct machine_check_event *evt,
 			printk("%s    Effective address: %016llx\n",
 			       level, evt->u.ue_error.effective_address);
 		if (evt->u.ue_error.physical_address_provided)
-			printk("%s      Physical address: %016llx\n",
+			printk("%s    Physical address:  %016llx\n",
 			       level, evt->u.ue_error.physical_address);
 		break;
 	case MCE_ERROR_TYPE_SLB:

index 9a31897..b272052 100644
@@ -55,6 +55,11 @@
 #endif
 
 /*
+ * maximum recursive depth of MCE exceptions
+ */
+#define MAX_MCE_DEPTH	4
+
+/*
  * EX_LR is only used in EXSLB and where it does not overlap with EX_DAR
  * EX_CCR similarly with DSISR, but being 4 byte registers there is a hole
  * in the save area so it's not necessary to overlap them. Could be used

index 75292c7..3a1226e 100644
@@ -204,7 +204,7 @@ struct mce_error_info {
 
 extern void save_mce_event(struct pt_regs *regs, long handled,
 			   struct mce_error_info *mce_err, uint64_t nip,
-			   uint64_t addr);
+			   uint64_t addr, uint64_t phys_addr);
 extern int get_mce_event(struct machine_check_event *mce, bool release);
 extern void release_mce_event(void);
 extern void machine_check_queue_event(void);

index fef1408..ee148f4 100644
@@ -82,7 +82,7 @@ static void mce_set_error_info(struct machine_check_event *mce,
  */
 void save_mce_event(struct pt_regs *regs, long handled,
 		    struct mce_error_info *mce_err,
-		    uint64_t nip, uint64_t addr)
+		    uint64_t nip, uint64_t addr, uint64_t phys_addr)
 {
 	int index = __this_cpu_inc_return(mce_nest_count) - 1;
 	struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]);

@@ -140,6 +140,10 @@ void save_mce_event(struct pt_regs *regs, long handled,
 	} else if (mce->error_type == MCE_ERROR_TYPE_UE) {
 		mce->u.ue_error.effective_address_provided = true;
 		mce->u.ue_error.effective_address = addr;
+		if (phys_addr != ULONG_MAX) {
+			mce->u.ue_error.physical_address_provided = true;
+			mce->u.ue_error.physical_address = phys_addr;
+		}
 	}
 	return;
 }

127 lines not on this page · raw message

index 0e584d5..2a888f6 100644
@@ -488,7 +488,8 @@ static int mce_find_instr_ea_and_pfn(struct pt_regs *regs, uint64_t *addr,
 
 static int mce_handle_ierror(struct pt_regs *regs,
 		const struct mce_ierror_table table[],
-		struct mce_error_info *mce_err, uint64_t *addr)
+		struct mce_error_info *mce_err, uint64_t *addr,
+		uint64_t *phys_addr)
 {
 	uint64_t srr1 = regs->msr;
 	int handled = 0;

@@ -540,8 +541,22 @@ static int mce_handle_ierror(struct pt_regs *regs,
 		}
 		mce_err->severity = table[i].severity;
 		mce_err->initiator = table[i].initiator;
-		if (table[i].nip_valid)
+		if (table[i].nip_valid) {
 			*addr = regs->nip;
+			if (mce_err->severity == MCE_SEV_ERROR_SYNC &&
+				table[i].error_type == MCE_ERROR_TYPE_UE) {
+				unsigned long pfn;
+
+				if (get_paca()->in_mce < MAX_MCE_DEPTH) {
+					pfn = addr_to_pfn(regs, regs->nip);
+					if (pfn != ULONG_MAX) {
+						*phys_addr =
+							(pfn << PAGE_SHIFT);
+						handled = 1;
+					}
+				}
+			}
+		}
 		return handled;
 	}
 

@@ -676,7 +691,8 @@ static long mce_handle_error(struct pt_regs *regs,
 		handled = mce_handle_derror(regs, dtable, &mce_err, &addr,
 				&phys_addr);
 	else
-		handled = mce_handle_ierror(regs, itable, &mce_err, &addr);
+		handled = mce_handle_ierror(regs, itable, &mce_err, &addr,
+				&phys_addr);
 
 	if (!handled && mce_err.error_type == MCE_ERROR_TYPE_UE)
 		handled = mce_handle_ue_error(regs);

index ee148f4..299553e 100644
@@ -39,11 +39,21 @@ static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event);
 static DEFINE_PER_CPU(int, mce_queue_count);
 static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event_queue);
 
+/* Queue for delayed MCE UE events. */
+static DEFINE_PER_CPU(int, mce_ue_count);
+static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT],
+					mce_ue_event_queue);
+
 static void machine_check_process_queued_event(struct irq_work *work);
+void machine_check_ue_event(struct machine_check_event *evt);
+static void machine_process_ue_event(struct work_struct *work);
+
 static struct irq_work mce_event_process_work = {
         .func = machine_check_process_queued_event,
 };
 
+DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
+
 static void mce_set_error_info(struct machine_check_event *mce,
 			       struct mce_error_info *mce_err)
 {

@@ -143,6 +153,7 @@ void save_mce_event(struct pt_regs *regs, long handled,
 		if (phys_addr != ULONG_MAX) {
 			mce->u.ue_error.physical_address_provided = true;
 			mce->u.ue_error.physical_address = phys_addr;
+			machine_check_ue_event(mce);
 		}
 	}
 	return;

@@ -197,6 +208,26 @@ void release_mce_event(void)
 	get_mce_event(NULL, true);
 }
 
+
+/*
+ * Queue up the MCE event which then can be handled later.
+ */
+void machine_check_ue_event(struct machine_check_event *evt)
+{
+	int index;
+
+	index = __this_cpu_inc_return(mce_ue_count) - 1;
+	/* If queue is full, just return for now. */
+	if (index >= MAX_MC_EVT) {
+		__this_cpu_dec(mce_ue_count);
+		return;
+	}
+	memcpy(this_cpu_ptr(&mce_ue_event_queue[index]), evt, sizeof(*evt));
+
+	/* Queue work to process this event later. */
+	schedule_work(&mce_ue_event_work);
+}
+
 /*
  * Queue up the MCE event which then can be handled later.
  */

@@ -219,7 +250,39 @@ void machine_check_queue_event(void)
 	/* Queue irq work to process this event later. */
 	irq_work_queue(&mce_event_process_work);
 }
-
+/*
+ * process pending MCE event from the mce event queue. This function will be
+ * called during syscall exit.
+ */
+static void machine_process_ue_event(struct work_struct *work)
+{
+	int index;
+	struct machine_check_event *evt;
+
+	while (__this_cpu_read(mce_ue_count) > 0) {
+		index = __this_cpu_read(mce_ue_count) - 1;
+		evt = this_cpu_ptr(&mce_ue_event_queue[index]);
+#ifdef CONFIG_MEMORY_FAILURE
+		/*
+		 * This should probably queued elsewhere, but
+		 * oh! well
+		 */
+		if (evt->error_type == MCE_ERROR_TYPE_UE) {
+			if (evt->u.ue_error.physical_address_provided) {
+				unsigned long pfn;
+
+				pfn = evt->u.ue_error.physical_address >>
+					PAGE_SHIFT;
+				memory_failure(pfn, SIGBUS, 0);
+			} else
+				pr_warn("Failed to identify bad address from "
+					"where the uncorrectable error (UE) "
+					"was generated\n");
+		}
+#endif
+		__this_cpu_dec(mce_ue_count);
+	}
+}
 /*
  * process pending MCE event from the mce event queue. This function will be
  * called during syscall exit.

@@ -227,6 +290,7 @@ void machine_check_queue_event(void)
 static void machine_check_process_queued_event(struct irq_work *work)
 {
 	int index;
+	struct machine_check_event *evt;
 
 	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
 

@@ -236,8 +300,8 @@ static void machine_check_process_queued_event(struct irq_work *work)
 	 */
 	while (__this_cpu_read(mce_queue_count) > 0) {
 		index = __this_cpu_read(mce_queue_count) - 1;
-		machine_check_print_event_info(
-				this_cpu_ptr(&mce_event_queue[index]), false);
+		evt = this_cpu_ptr(&mce_event_queue[index]);
+		machine_check_print_event_info(evt, false);
 		__this_cpu_dec(mce_queue_count);
 	}
 }