-extern int register_die_notifier(struct notifier_block *);
-extern int unregister_die_notifier(struct notifier_block *);
-extern struct atomic_notifier_head sparc64die_chain;
+/* Note - you should never unregister because that can race with NMIs.
+ * If you really want to do it first unregister - then synchronize_sched
+ * - then free.
+ */
+int register_die_notifier(struct notifier_block *nb);
+extern struct notifier_block *sparc64die_chain;