[SPARC64]: Add sparc64die_chain as on x86{,_64}

arch/sparc64/kernel/traps.c

@@ -36,10 +36,24 @@
 #include <asm/psrcompat.h>
 #include <asm/processor.h>
 #include <asm/timer.h>
+#include <asm/kdebug.h>
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
 #endif
 
+struct notifier_block *sparc64die_chain;
+static spinlock_t die_notifier_lock = SPIN_LOCK_UNLOCKED;
+
+int register_die_notifier(struct notifier_block *nb)
+{
+	int err = 0;
+	unsigned long flags;
+	spin_lock_irqsave(&die_notifier_lock, flags);
+	err = notifier_chain_register(&sparc64die_chain, nb);
+	spin_unlock_irqrestore(&die_notifier_lock, flags);
+	return err;
+}
+
 /* When an irrecoverable trap occurs at tl > 0, the trap entry
  * code logs the trap state registers at every level in the trap
  * stack.  It is found at (pt_regs + sizeof(pt_regs)) and the layout

include/asm-sparc64/kdebug.h

 #ifndef _SPARC64_KDEBUG_H
 #define _SPARC64_KDEBUG_H
 
-/* 
- * No kernel debugger on sparc64. Kept here because drivers/sbus/char/
- * includes it for sparc32 sake.
+/* Nearly identical to x86_64/i386 code. */
+
+#include <linux/notifier.h>
+
+struct pt_regs;
+
+struct die_args {
+	struct pt_regs *regs;
+	const char *str;
+	long err;
+	int trapnr;
+	int signr;
+};
+
+/* Note - you should never unregister because that can race with NMIs.
+ * If you really want to do it first unregister - then synchronize_kernel
+ * - then free.
  */
+int register_die_notifier(struct notifier_block *nb);
+extern struct notifier_block *sparc64die_chain;
+
+/* Grossly misnamed. */
+enum die_val {
+	DIE_OOPS = 1,
+	DIE_DEBUG,
+	DIE_PANIC,
+	DIE_NMI,
+	DIE_DIE,
+	DIE_KERNELDEBUG,
+	DIE_TRAP,
+	DIE_GPF,
+	DIE_CALL,
+	DIE_PAGE_FAULT,
+};
+
+static inline int notify_die(enum die_val val,char *str, struct pt_regs *regs,
+			     long err, int trap, int sig)
+{
+	struct die_args args = { .regs		= regs,
+				 .str		= str,
+				 .err		= err,
+				 .trapnr	= trap,
+				 .signr		= sig };
+
+	return notifier_call_chain(&sparc64die_chain, val, &args);
+}
 
 #endif