x86: optimize page faults like all other achitectures and kill notifier cruft

x86(-64) are the last architectures still using the page fault notifier
cruft for the kprobes page fault hook.  This patch converts them to the
proper direct calls, and removes the now unused pagefault notifier bits
aswell as the cruft in kprobes.c that was related to this mess.

I know Andi didn't really like this, but all other architecture maintainers
agreed the direct calls are much better and besides the obvious cruft
removal a common way of dealing with kprobes across architectures is
important aswell.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix sparc64]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Andi Kleen <ak@suse.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-avr32/kdebug.h

@@ -1,26 +1,10 @@
 #ifndef __ASM_AVR32_KDEBUG_H
 #define __ASM_AVR32_KDEBUG_H
 
-#include <linux/notifier.h>
-
 /* Grossly misnamed. */
 enum die_val {
 	DIE_BREAKPOINT,
 	DIE_SSTEP,
 };
 
-/*
- * These are only here because kprobes.c wants them to implement a
- * blatant layering violation.  Will hopefully go away soon once all
- * architectures are updated.
- */
-static inline int register_page_fault_notifier(struct notifier_block *nb)
-{
-	return 0;
-}
-static inline int unregister_page_fault_notifier(struct notifier_block *nb)
-{
-	return 0;
-}
-
 #endif /* __ASM_AVR32_KDEBUG_H */

include/asm-avr32/kprobes.h

@@ -17,8 +17,6 @@ typedef u16	kprobe_opcode_t;
 #define BREAKPOINT_INSTRUCTION	0xd673	/* breakpoint */
 #define MAX_INSN_SIZE		2
 
-#define ARCH_INACTIVE_KPROBE_COUNT 1
-
 #define arch_remove_kprobe(p)	do { } while (0)
 
 /* Architecture specific copy of original instruction */