From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761735Ab3DBQvf (ORCPT ); Tue, 2 Apr 2013 12:51:35 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:54735 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761656Ab3DBQvd (ORCPT ); Tue, 2 Apr 2013 12:51:33 -0400 Date: Tue, 2 Apr 2013 17:51:14 +0100 From: Will Deacon To: Paul Bolle Cc: Russell King , Nicolas Pitre , Catalin Marinas , Marc Zyngier , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ARM: Fix typo "CONFIG_LPAE" twice Message-ID: <20130402165114.GI6608@mudshark.cambridge.arm.com> References: <1364563104.1345.74.camel@x61.thuisdomein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1364563104.1345.74.camel@x61.thuisdomein> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Paul, On Fri, Mar 29, 2013 at 01:18:24PM +0000, Paul Bolle wrote: > Signed-off-by: Paul Bolle > --- > 0) Untested. > > 1) This typo was first introduced in v3.4: commit > e5ab85800820edd907d3f43f285e1232f84d5a41 ("ARM: 7382/1: mm: truncate > memory banks to fit in 4GB space for classic MMU"). The second instance > was added in v3.9-rc2: commit d61947a164760ac520cb416768afdf38c33d60e7 > (" ARM: 7657/1: head: fix swapper and idmap population with LPAE and > big-endian"). So testing is really needed here. > > 2) If this passes (review and) testing, this probably needs to go to > stable too. > > arch/arm/kernel/head.S | 2 +- > arch/arm/kernel/setup.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index e0eb9a1..8bac553 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -267,7 +267,7 @@ __create_page_tables: > addne r6, r6, #1 << SECTION_SHIFT > strne r6, [r3] > > -#if defined(CONFIG_LPAE) && defined(CONFIG_CPU_ENDIAN_BE8) > +#if defined(CONFIG_ARM_LPAE) && defined(CONFIG_CPU_ENDIAN_BE8) > sub r4, r4, #4 @ Fixup page table pointer > @ for 64-bit descriptors > #endif The problem with this code is that there are very few people with platforms on which they can test it. You need an LPAE-capable CPU (Cortex-A7 or Cortex-A15) sitting on a big-endian platform. The only platform that I have for that is KVM, which doesn't have earlyprintk support. Now, without the offending patch, such a configuration didn't even boot, but I can't verify that the mapping actually works. Of course, what you have written was the intended behaviour, so perhaps we should just go with that for the time being. Will