From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753969AbYE2ESr (ORCPT ); Thu, 29 May 2008 00:18:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750747AbYE2ESi (ORCPT ); Thu, 29 May 2008 00:18:38 -0400 Received: from mta23.gyao.ne.jp ([125.63.38.249]:21955 "EHLO mx.gate01.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750709AbYE2ESh (ORCPT ); Thu, 29 May 2008 00:18:37 -0400 Date: Thu, 29 May 2008 13:16:31 +0900 From: Paul Mundt To: Jeremy Fitzhardinge Cc: Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , Paul Mackerras , Sam Ravnborg Subject: Re: [PATCH 1/3] make page-aligned data and bss less fragile Message-ID: <20080529041631.GA12619@linux-sh.org> Mail-Followup-To: Paul Mundt , Jeremy Fitzhardinge , Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , Paul Mackerras , Sam Ravnborg References: <483D8292.40808@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <483D8292.40808@goop.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 28, 2008 at 05:04:34PM +0100, Jeremy Fitzhardinge wrote: > Making a variable page-aligned by using > __attribute__((section(".data.page_aligned"))) is fragile because if > sizeof(variable) is not also a multiple of page size, it leaves > variables in the remainder of the section unaligned. > > This patch introduces two new qualifiers, __page_aligned_data and > __page_aligned_bss to set the section *and* the alignment of > variables. This makes page-aligned variables more robust because the > linker will make sure they're aligned properly. Unfortunately it > requires *all* page-aligned data to use these macros... > > It also updates arch/x86's use of page-aligned variables, since its > the heaviest user of them in the kernel. The change to > arch/x86/xen/mmu.c fixes an actual bug, but the rest are cleanups > and to set a precident. > > [ I don't know if this would be easier to manage by splitting the > x86 part out from the common part. Two following patches apply to > powerpc and sh; they're purely decorative. ] > > Signed-off-by: Jeremy Fitzhardinge > Cc: Paul Mundt > Cc: Paul Mackerras Acked-by: Paul Mundt