[PATCH] Kprobes/IA64: kdebug die notification mechanism

As many of you know that kprobes exist in the main line kernel for various
architecture including i386, x86_64, ppc64 and sparc64.  Attached patches
following this mail are a port of Kprobes and Jprobes for IA64.

I have tesed this patches for kprobes and Jprobes and this seems to work fine.
 I have tested this patch by inserting kprobes on various slots and various
templates including various types of branch instructions.

I have also tested this patch using the tool
http://marc.theaimsgroup.com/?l=linux-kernel&m=111657358022586&w=2 and the
kprobes for IA64 works great.

Here is list of TODO things and pathes for the same will appear soon.

1) Support kprobes on "mov r1=ip" type of instruction
2) Support Kprobes and Jprobes to exist on the same address
3) Support Return probes
3) Architecture independent cleanup of kprobes

This patch adds the kdebug die notification mechanism needed by Kprobes.

For break instruction on Branch type slot, imm21 is ignored and value
zero is placed in IIM register, hence we need to handle kprobes
for switch case zero.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Rusty Lynch <Rusty.lynch@intel.com>

From: Rusty Lynch <rusty.lynch@intel.com>

At the point in traps.c where we recieve a break with a zero value, we can
not say if the break was a result of a kprobe or some other debug facility.

This simple patch changes the informational string to a more correct "break
0" value, and applies to the 2.6.12-rc2-mm2 tree with all the kprobes
patches that were just recently included for the next mm cut.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 4174ec999dde..ff62551eb3a1 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -14,6 +14,7 @@
 #include <asm/processor.h>
 #include <asm/system.h>
 #include <asm/uaccess.h>
+#include <asm/kdebug.h>
 
 extern void die (char *, struct pt_regs *, long);
 
@@ -102,6 +103,13 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 		goto bad_area_no_up;
 #endif
 
+	/*
+	 * This is to handle the kprobes on user space access instructions
+	 */
+	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
+					SIGSEGV) == NOTIFY_STOP)
+		return;
+
 	down_read(&mm->mmap_sem);
 
 	vma = find_vma_prev(mm, address, &prev_vma);