From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932605AbaH0FU0 (ORCPT ); Wed, 27 Aug 2014 01:20:26 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:32097 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751000AbaH0FUZ (ORCPT ); Wed, 27 Aug 2014 01:20:25 -0400 From: Wang Nan To: "David A. Long" , Russell King , Jon Medhurst , Taras Kondratiuk , Ben Dooks CC: Wang Nan , , , Subject: [PATCH] ARM: probes: return directly when emulate not set Date: Wed, 27 Aug 2014 13:08:29 +0800 Message-ID: <1409116109-67330-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When kprobe decoding instruction, original code calls instruction specific decoder if emulate is set to false. However, instructions with DECODE_TYPE_EMULATE are in fact don't have their decoder. What in the action table are in fact handlers. For example: /* LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx */ /* STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx */ DECODE_EMULATEX (0x0e5000d0, 0x004000d0, PROBES_LDRSTRD, REGS(NOPCWB, NOPCX, 0, 0, 0)), and const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = { ... [PROBES_LDRSTRD] = {.handler = emulate_ldrdstrd}, ... In this situation, original code calls 'emulate_ldrdstrd' as a decoder, which is obviously incorrect. This patch makes it returns INSN_GOOD directly when 'emulate' is not true. Signed-off-by: Wang Nan Cc: "David A. Long" Cc: Russell King Cc: Jon Medhurst Cc: Taras Kondratiuk Cc: Ben Dooks --- arch/arm/kernel/probes.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/arm/kernel/probes.c b/arch/arm/kernel/probes.c index a8ab540..1c77b8d 100644 --- a/arch/arm/kernel/probes.c +++ b/arch/arm/kernel/probes.c @@ -436,8 +436,7 @@ probes_decode_insn(probes_opcode_t insn, struct arch_probes_insn *asi, struct decode_emulate *d = (struct decode_emulate *)h; if (!emulate) - return actions[d->handler.action].decoder(insn, - asi, h); + return INSN_GOOD; asi->insn_handler = actions[d->handler.action].handler; set_emulated_insn(insn, asi, thumb); -- 1.8.4