Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752670AbdHKJ0I (ORCPT ); Fri, 11 Aug 2017 05:26:08 -0400 Received: from mail-io0-f181.google.com ([209.85.223.181]:38570 "EHLO mail-io0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbdHKJ0H (ORCPT ); Fri, 11 Aug 2017 05:26:07 -0400 MIME-Version: 1.0 In-Reply-To: <20170811092213.mdmzqtm2lp6ltlxt@armageddon.cambridge.arm.com> References: <20170811092213.mdmzqtm2lp6ltlxt@armageddon.cambridge.arm.com> From: Ard Biesheuvel Date: Fri, 11 Aug 2017 10:26:06 +0100 Message-ID: Subject: Re: New assembler warnings with binutils 2.29 To: Catalin Marinas Cc: Laura Abbott , Will Deacon , Arnd Bergmann , Linux Kernel Mailing List , linux-arm-kernel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1203 Lines: 31 On 11 August 2017 at 10:22, Catalin Marinas wrote: > On Thu, Aug 10, 2017 at 01:13:22PM -0700, Laura Abbott wrote: >> Fedora rawhide recently upgraded to binutils 2.29 and this seems >> to produce new warnings: >> >> ./arch/arm64/include/asm/assembler.h: Assembler messages: >> ./arch/arm64/include/asm/assembler.h:125: Warning: ignoring attempt to redefine built-in register 'lr' >> >> This is >> >> /* >> * Register aliases. >> */ >> lr .req x30 // link register > > Strange, does gas now think 'lr' is a general purpose register (aliased > to x30)? It never was and IIRC the toolchain people many years ago > refused to add it, hence the alias above in the kernel. I wonder if they > added 'fp' as well... > > We could remove the alias and replace all 'lr' instances with 'x30' > throughout the kernel (no too many) or we add some #ifdef around the > above based on the binutils version. > This is annoying. Replacing x30 with lr achieves the opposite of the intent of the binutils change. And using #ifdefs is inaccurate, because you can't really test the binutils version only the GCC version, and those are not tightly coupled. Can you .unreq it?