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 X-Spam-Level: X-Spam-Status: No, score=-16.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 968F2C433E0 for ; Thu, 30 Jul 2020 17:24:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 724F720829 for ; Thu, 30 Jul 2020 17:24:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730194AbgG3RYg (ORCPT ); Thu, 30 Jul 2020 13:24:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:38564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726353AbgG3RYf (ORCPT ); Thu, 30 Jul 2020 13:24:35 -0400 Received: from gaia (unknown [95.146.230.158]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F144020809; Thu, 30 Jul 2020 17:24:33 +0000 (UTC) Date: Thu, 30 Jul 2020 18:24:31 +0100 From: Catalin Marinas To: Sami Tolvanen Cc: Will Deacon , Ard Biesheuvel , Nick Desaulniers , Kees Cook , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH v2] arm64/alternatives: move length validation inside the subsection Message-ID: <20200730172430.GC3128@gaia> References: <20200729215152.662225-1-samitolvanen@google.com> <20200730153701.3892953-1-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200730153701.3892953-1-samitolvanen@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 30, 2020 at 08:37:01AM -0700, Sami Tolvanen wrote: > Commit f7b93d42945c ("arm64/alternatives: use subsections for replacement > sequences") breaks LLVM's integrated assembler, because due to its > one-pass design, it cannot compute instruction sequence lengths before the > layout for the subsection has been finalized. This change fixes the build > by moving the .org directives inside the subsection, so they are processed > after the subsection layout is known. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1078 > Fixes: f7b93d42945c ("arm64/alternatives: use subsections for replacement sequences") > Signed-off-by: Sami Tolvanen > --- > v1 -> v2: > - Added the missing Fixes tag and dropped CC: stable@. > > --- > arch/arm64/include/asm/alternative.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h > index 12f0eb56a1cc..619db9b4c9d5 100644 > --- a/arch/arm64/include/asm/alternative.h > +++ b/arch/arm64/include/asm/alternative.h > @@ -77,9 +77,9 @@ static inline void apply_alternatives_module(void *start, size_t length) { } > "663:\n\t" \ > newinstr "\n" \ > "664:\n\t" \ > - ".previous\n\t" \ > ".org . - (664b-663b) + (662b-661b)\n\t" \ > - ".org . - (662b-661b) + (664b-663b)\n" \ > + ".org . - (662b-661b) + (664b-663b)\n\t" \ > + ".previous\n" \ > ".endif\n" Acked-by: Catalin Marinas There are a few instances of the .org test outside the subsection, though using in .S files. Are those ok? -- Catalin