From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751806AbdG0U57 (ORCPT ); Thu, 27 Jul 2017 16:57:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40206 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728AbdG0U50 (ORCPT ); Thu, 27 Jul 2017 16:57:26 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A71773A834B Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jpoimboe@redhat.com From: Josh Poimboeuf To: Ingo Molnar Cc: Arnd Bergmann , linux-kernel@vger.kernel.org Subject: [PATCH 2/4] objtool: Skip unreachable warnings for 'alt' instructions Date: Thu, 27 Jul 2017 15:56:54 -0500 Message-Id: In-Reply-To: References: X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 27 Jul 2017 20:57:26 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a whitelisted function uses one of the ALTERNATIVE macros, it produces false positive warnings like: arch/x86/kvm/vmx.o: warning: objtool: .altinstr_replacement+0x0: unreachable instruction arch/x86/kvm/svm.o: warning: objtool: .altinstr_replacement+0x6e: unreachable instruction There's no easy way to whitelist alternative instructions, so instead just skip any 'unreachable' warnings associated with them. Reported-by: Arnd Bergmann Signed-off-by: Josh Poimboeuf --- tools/objtool/check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index d07bf4a62b45..4f0c4aea8f6f 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1746,8 +1746,13 @@ static bool ignore_unreachable_insn(struct instruction *insn) /* * Ignore any unused exceptions. This can happen when a whitelisted * function has an exception table entry. + * + * Also ignore alternative replacement instructions. This can happen + * when a whitelisted function uses one of the ALTERNATIVE macros. */ - if (!strcmp(insn->sec->name, ".fixup")) + if (!strcmp(insn->sec->name, ".fixup") || + !strcmp(insn->sec->name, ".altinstr_replacement") || + !strcmp(insn->sec->name, ".altinstr_aux")) return true; /* -- 2.13.3