From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FDB5C4332F for ; Tue, 18 Oct 2022 00:51:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230308AbiJRAvV (ORCPT ); Mon, 17 Oct 2022 20:51:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229898AbiJRAvJ (ORCPT ); Mon, 17 Oct 2022 20:51:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC74379A52; Mon, 17 Oct 2022 17:51:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 39CDCB81BE1; Tue, 18 Oct 2022 00:12:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06F87C43142; Tue, 18 Oct 2022 00:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666051928; bh=Rh81RPbhx4/y1NV0oUGFkBZ+zKY1q380V3RQ3dzOUqk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eWdqEjXUqfJnKiEntEjsontxLwwetEitqSJpLfTCv66oIIhKpfZ4X35l9asXPbzkr 6yQ+yrLiCft6mD1ikd10gbdQUgkHQVZwEoRyGPFzteybc8MoVfk/nM2prMPpPmpzrh hnKZpnfL7DY+jzJHQPIEXhbkc7djnVC9z1WcA45H+vLrb64AEjdJlC88ivnaVx/rLn kDvwgdIf0LzlTnHmVbEEyvKl2jAJgv2YX1xvlbgNHo83QL72k8meYH8/9JMpLUr/7L b8E+A718sQ/Q2Y3/93ZsoFP+UcpGkwzL6UJ2kpwroUEN0Ip1xx9CsS8KeS+GkM/QZz TTXbxHAKb8cBg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Peter Zijlstra , Masami Hiramatsu , Sasha Levin , jpoimboe@kernel.org, bp@suse.de, tony.luck@intel.com, fenghua.yu@intel.com Subject: [PATCH AUTOSEL 4.9 2/8] objtool,x86: Teach decode about LOOP* instructions Date: Mon, 17 Oct 2022 20:11:56 -0400 Message-Id: <20221018001202.2732458-2-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221018001202.2732458-1-sashal@kernel.org> References: <20221018001202.2732458-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit 7a7621dfa417aa3715d2a3bd1bdd6cf5018274d0 ] When 'discussing' control flow Masami mentioned the LOOP* instructions and I realized objtool doesn't decode them properly. As it turns out, these instructions are somewhat inefficient and as such unlikely to be emitted by the compiler (a few vmlinux.o checks can't find a single one) so this isn't critical, but still, best to decode them properly. Reported-by: Masami Hiramatsu (Google) Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/Yxhd4EMKyoFoH9y4@hirez.programming.kicks-ass.net Signed-off-by: Sasha Levin --- tools/objtool/arch/x86/decode.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 540a209b78ab..faaf2820e932 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -440,6 +440,12 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, *type = INSN_CONTEXT_SWITCH; break; + case 0xe0: /* loopne */ + case 0xe1: /* loope */ + case 0xe2: /* loop */ + *type = INSN_JUMP_CONDITIONAL; + break; + case 0xe8: *type = INSN_CALL; break; -- 2.35.1