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 11F56C43217 for ; Tue, 18 Oct 2022 00:13:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231354AbiJRANr (ORCPT ); Mon, 17 Oct 2022 20:13:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231351AbiJRAMj (ORCPT ); Mon, 17 Oct 2022 20:12:39 -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 08BCA88A1C; Mon, 17 Oct 2022 17:09:18 -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 DE949B81B62; Tue, 18 Oct 2022 00:08:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B91ECC433D6; Tue, 18 Oct 2022 00:08:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666051738; bh=KtSPXtltLaR39nQ58teUKsRR/MN4D9N1XdSowoX1sb0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J2DJb5S0dnqtVv99jNsT0a++b40zHzP/Klr6C+pdOxjX2kFE3pP8HoXGv6Eri7ua7 id0CG6Rz6qAzriff6HT4YNkz9b609CEX8tVaLApt15hDaPbwsa4MyHGlckqdF0MA7K TaaOO18agUXrWnzfno8PVeL6nIkfoc0yUIQLmf5IJwpSltmDyv/qyyM82jPdtn9kr6 fn24YAo7VDzbrw+l45KdQusK5CyOwEl35/09YDIOXHt3W1oTD11SK2OcAQvY/mnMcm XQgjP9dGOWXx2HLv1tWjQru8471ZLfTepJJrIXFiF29HpMt7GTVGz1YSNO3zZFXqFh OKc1rPXt5P84g== 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, fenghua.yu@intel.com, tony.luck@intel.com Subject: [PATCH AUTOSEL 5.19 09/29] objtool,x86: Teach decode about LOOP* instructions Date: Mon, 17 Oct 2022 20:08:18 -0400 Message-Id: <20221018000839.2730954-9-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221018000839.2730954-1-sashal@kernel.org> References: <20221018000839.2730954-1-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 c260006106be..1c253b4b7ce0 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -635,6 +635,12 @@ int arch_decode_instruction(struct objtool_file *file, const 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; /* -- 2.35.1