From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752781Ab3KDLtZ (ORCPT ); Mon, 4 Nov 2013 06:49:25 -0500 Received: from fw-tnat.cambridge.arm.com ([217.140.96.21]:50297 "EHLO cam-smtp0.cambridge.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752554Ab3KDLtW (ORCPT ); Mon, 4 Nov 2013 06:49:22 -0500 Date: Mon, 4 Nov 2013 11:28:40 +0000 From: Catalin Marinas To: Mark Salter Cc: Will Deacon , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] arm64: add PAGE_ALIGNED_DATA to linker script Message-ID: <20131104112840.GC2527@arm.com> References: <1381264659-11132-1-git-send-email-msalter@redhat.com> <20131009101447.GC5985@mudshark.cambridge.arm.com> <1381493921.8305.63.camel@deneb.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381493921.8305.63.camel@deneb.redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 11, 2013 at 01:18:41PM +0100, Mark Salter wrote: > On Wed, 2013-10-09 at 11:14 +0100, Will Deacon wrote: > > > @@ -110,6 +110,7 @@ SECTIONS > > > */ > > > INIT_TASK_DATA(THREAD_SIZE) > > > NOSAVE_DATA > > > + PAGE_ALIGNED_DATA(PAGE_SIZE) > > > CACHELINE_ALIGNED_DATA(64) > > > READ_MOSTLY_DATA(64) > > > > Can we just replace this chunk with RW_DATA_SECTION(64, PAGE_SIZE, > > THREAD_SIZE) instead? > > > > I took a look at this. It can be done, but the RW_DATA_SECTION aligns > data to PAGE_SIZE where the existing alignment is THREAD_SIZE. So using > RW_DATA_SECTION would waste some space if using 64K pagesize. I think that's ok, especially since we may get security patches in the future to create more restrictive page table attributes (well, with the drawback of more TLB pressure). So I'm for more cleanup in the vmlinux file by using the generic defines. -- Catalin