1 files changed, 57 insertions, 7 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index e9c9d0a..cbe82b5 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -95,13 +95,6 @@ static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
 static DEFINE_PER_CPU(struct mce, mces_seen);
 static int			cpu_missing;
 
-/*
- * CPU/chipset specific EDAC code can register a notifier call here to print
- * MCE errors in a human-readable form.
- */
-ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
-EXPORT_SYMBOL_GPL(x86_mce_decoder_chain);
-
 /* MCA banks polled by the period polling timer for corrected events */
 DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
 	[0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL
@@ -109,6 +102,12 @@ DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
 
 static DEFINE_PER_CPU(struct work_struct, mce_work);
 
+/*
+ * CPU/chipset specific EDAC code can register a notifier call here to print
+ * MCE errors in a human-readable form.
+ */
+ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
+
 /* Do initial initialization of a struct mce */
 void mce_setup(struct mce *m)
 {
@@ -188,6 +187,57 @@ void mce_log(struct mce *mce)
 	set_bit(0, &mce_need_notify);
 }
 
+static void drain_mcelog_buffer(void)
+{
+	unsigned int next, i, prev = 0;
+
+	next = rcu_dereference_check_mce(mcelog.next);
+
+	do {
+		struct mce *m;
+
+		/* drain what was logged during boot */
+		for (i = prev; i < next; i++) {
+			unsigned long start = jiffies;
+			unsigned retries = 1;
+
+			m = &mcelog.entry[i];
+
+			while (!m->finished) {
+				if (time_after_eq(jiffies, start + 2*retries))
+					retries++;
+
+				cpu_relax();
+
+				if (!m->finished && retries >= 4) {
+					pr_err("MCE: skipping error being logged currently!\n");
+					break;
+				}
+			}
+			smp_rmb();
+			atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
+		}
+
+		memset(mcelog.entry + prev, 0, (next - prev) * sizeof(*m));
+		prev = next;
+		next = cmpxchg(&mcelog.next, prev, 0);
+	} while (next != prev);
+}
+
+
+void mce_register_decode_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);
+	drain_mcelog_buffer();
+}
+EXPORT_SYMBOL_GPL(mce_register_decode_chain);
+
+void mce_unregister_decode_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
+
 static void print_mce(struct mce *m)
 {
 	int ret = 0;