From 444956677eccfcdfe05de761e1286f62c423ce88 Mon Sep 17 00:00:00 2001
From: Jon Medhurst <tixy@yxit.co.uk>
Date: Sat, 2 Jul 2011 16:25:47 +0100
Subject: [PATCH] ARM: kprobes: Reject 16-bit Thumb SVC and UNDEFINED
 instructions

SVC (SWI) instructions shouldn't occur in kernel code so we don't
need to be able to probe them.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
---
 arch/arm/kernel/kprobes-thumb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c
index e496948fefac..997fc6d59a40 100644
--- a/arch/arm/kernel/kprobes-thumb.c
+++ b/arch/arm/kernel/kprobes-thumb.c
@@ -464,6 +464,14 @@ const union decode_item kprobe_decode_thumb16_table[] = {
 	/* LDM				1100 1xxx xxxx xxxx */
 	DECODE_EMULATE	(0xf000, 0xc000, t16_emulate_loregs_rwflags),
 
+	/*
+	 * Conditional branch, and Supervisor Call
+	 */
+
+	/* Permanently UNDEFINED	1101 1110 xxxx xxxx */
+	/* SVC				1101 1111 xxxx xxxx */
+	DECODE_REJECT	(0xfe00, 0xde00),
+
 	DECODE_END
 };