Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753259AbcKRAIL (ORCPT ); Thu, 17 Nov 2016 19:08:11 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39650 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753082AbcKRAIH (ORCPT ); Thu, 17 Nov 2016 19:08:07 -0500 Subject: Re: [PATCH] x86: avoid warning for zero-filling .bss To: Josh Poimboeuf , Arnd Bergmann References: <20161116141726.2013389-1-arnd@arndb.de> <20161117210248.u3velicjxwwbwql5@treble> <12902246.avh8vXRAfV@wuerfel> <20161117224445.n3nerymee5jnrq75@treble> Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Andy Lutomirski , linux-kernel@vger.kernel.org From: "H. Peter Anvin" Message-ID: Date: Thu, 17 Nov 2016 16:07:47 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161117224445.n3nerymee5jnrq75@treble> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 27 On 11/17/16 14:44, Josh Poimboeuf wrote: > On Thu, Nov 17, 2016 at 11:32:30PM +0100, Arnd Bergmann wrote: >> On Thursday, November 17, 2016 3:02:48 PM CET Josh Poimboeuf wrote: >>> On Wed, Nov 16, 2016 at 03:17:09PM +0100, Arnd Bergmann wrote: >>>> The latest binutils are warning about a .fill directive with an explicit >>>> value in a .bss section: >>>> >>>> arch/x86/kernel/head_32.S: Assembler messages: >>>> arch/x86/kernel/head_32.S:677: Warning: ignoring fill value in section `.bss..page_aligned' >>>> arch/x86/kernel/head_32.S:679: Warning: ignoring fill value in section `.bss..page_aligned' >>>> >>>> This comes from the 'ENTRY()' macro padding the space between the symbols >>>> with 'nop'. Open-coding the .globl directive without the padding >>>> avoids that warning. >>> >>> How is there space between the symbols? Aren't they already aligned? >> >> My understanding is that they are aligned, it's just that gas complains >> about the .align directive with a nonzero fill value. > > Ah, I see now. In that case your patch looks fine to me. > Yes, ENTRY() is for code. -hpa