debug: add notifier chain debugging, v2

- unbreak ia64 (and powerpc) where function pointers dont
  point at code but at data (reported by Tony Luck)

[ mingo@elte.hu: various cleanups ]

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2651f80..4e1366b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -187,6 +187,9 @@
 extern int core_kernel_text(unsigned long addr);
 extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
+extern int func_ptr_is_kernel_text(void *ptr);
+extern void *dereference_function_descriptor(void *ptr);
+
 struct pid;
 extern struct pid *session_of_pgrp(struct pid *pgrp);