[PATCH] powerpc/mce: Add MCE notification chain

[Ganesh Goudar]

From: Santosh S <santosh at fossix.org>

Introduce notification chain which lets know about uncorrected memory
errors(UE). This would help prospective users in pmem or nvdimm subsystem
to track bad blocks for better handling of persistent memory allocations.

Signed-off-by: Santosh S <santosh at fossix.org>
Signed-off-by: Ganesh Goudar <ganeshgr at linux.ibm.com>
---
 arch/powerpc/include/asm/mce.h |  2 ++
 arch/powerpc/kernel/mce.c      | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
index 6a6ddaabdb34..6e222a94a68a 100644
--- a/arch/powerpc/include/asm/mce.h
+++ b/arch/powerpc/include/asm/mce.h
@@ -218,6 +218,8 @@ extern void machine_check_queue_event(void);
 extern void machine_check_print_event_info(struct machine_check_event *evt,
 					   bool user_mode, bool in_guest);
 unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr);
+int mce_register_notifier(struct notifier_block *nb);
+int mce_unregister_notifier(struct notifier_block *nb);
 #ifdef CONFIG_PPC_BOOK3S_64
 void flush_and_reload_slb(void);
 #endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 34c1001e9e8b..f50d7f56c02c 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -47,6 +47,20 @@ static struct irq_work mce_ue_event_irq_work = {
 
 DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
 
+static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
+
+int mce_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&mce_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_notifier);
+
+int mce_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_notifier);
+
 static void mce_set_error_info(struct machine_check_event *mce,
 			       struct mce_error_info *mce_err)
 {
@@ -263,6 +277,7 @@ static void machine_process_ue_event(struct work_struct *work)
 	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]);
+		blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
 #ifdef CONFIG_MEMORY_FAILURE
 		/*
 		 * This should probably queued elsewhere, but
-- 
2.17.2