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 A5BC8C4332F for ; Tue, 18 Oct 2022 00:16:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231794AbiJRAQ2 (ORCPT ); Mon, 17 Oct 2022 20:16:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231804AbiJRAOX (ORCPT ); Mon, 17 Oct 2022 20:14:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25D8489ACC; Mon, 17 Oct 2022 17:11:23 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 8619061348; Tue, 18 Oct 2022 00:11:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00720C433D7; Tue, 18 Oct 2022 00:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666051872; bh=s+K9wJScfNERIDs7MapJXz8te1pff7k7NPx9WY6kqb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kXNtGP47q6P3/J2HsXvDsMV3EPwq7feO2Vx326P2RXbOiCRfdoW+yh9CxA+wrn/K6 Q3Axq0yEEJFxruDgt+hR8kh8MRkb5jw3z5uKGYpokn7URXJmoepCFJQ0DAfRrqfuRI kMRhaG3OOSSi9Hioz5it4eBZjhRasMO2uemewVN+rCDOI8mGl8vAfpEZfMVKvcnDo1 zWjUAtSM3577zLlOfepBpsdWBd5N7vCAdGhDbTinpRNgXod3MdhOm5dF4viIgdU7LL DQCqsT37Wlng/8rWWdaaBbElKOQ0M8z/uGVBflf52Azi+WQra06PldCDXud3fxl0K6 LIMEcdfP7CZrQ== 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 5.4 05/13] objtool,x86: Teach decode about LOOP* instructions Date: Mon, 17 Oct 2022 20:10:54 -0400 Message-Id: <20221018001102.2731930-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221018001102.2731930-1-sashal@kernel.org> References: <20221018001102.2731930-1-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 a62e032863a8..4a7652719130 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -435,6 +435,12 @@ 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