[PATCH] kprobes: Minor i386 changes required for porting kprobes to x86_64

- Kprobes structure has been modified to support copying of original
  instruction as required by the architecture.  On x86_64 normal pages we
  get from kmalloc or vmalloc are not executable.  Single-stepping an
  instruction on such a page yields an oops.  So instead of storing the
  instruction copies in their respective kprobe objects, we allocate a
  page, map it executable, and store all the instruction copies there and
  store the pointer of the copied instruction in the specific kprobes
  object.

- jprobe_return_end is moved into inline assembly to avoid compiler
  optimization.

- arch_prepare_kprobe() now returns an integer,since
  arch_prepare_kprobe() might fail on other architectures.

- added arch_remove_kprobe() routine, since other architectures requires
  it.

Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ca4e28b4c6a759..d3d1321b0e5c2c 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -84,10 +84,13 @@ int register_kprobe(struct kprobe *p)
 		ret = -EEXIST;
 		goto out;
 	}
+
+	if ((ret = arch_prepare_kprobe(p)) != 0) {
+		goto out;
+	}
 	hlist_add_head(&p->hlist,
 		       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
 
-	arch_prepare_kprobe(p);
 	p->opcode = *p->addr;
 	*p->addr = BREAKPOINT_INSTRUCTION;
 	flush_icache_range((unsigned long) p->addr,
@@ -101,6 +104,7 @@ void unregister_kprobe(struct kprobe *p)
 {
 	unsigned long flags;
 	spin_lock_irqsave(&kprobe_lock, flags);
+	arch_remove_kprobe(p);
 	*p->addr = p->opcode;
 	hlist_del(&p->hlist);
 	flush_icache_range((unsigned long) p->addr,