From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751916AbcBLJq6 (ORCPT ); Fri, 12 Feb 2016 04:46:58 -0500 Received: from mout.kundenserver.de ([212.227.17.24]:64403 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751784AbcBLJqd (ORCPT ); Fri, 12 Feb 2016 04:46:33 -0500 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Russell King - ARM Linux , Kees Cook , Vladimir Murzin , Victor Kamensky , Nicolas Pitre , Catalin Marinas , Ard Biesheuvel , Will Deacon , "linux-kernel@vger.kernel.org" , Laura Abbott Subject: Re: [PATCH v2] ARM: mm: mark section-aligned portion of rodata NX Date: Fri, 12 Feb 2016 10:45:55 +0100 Message-ID: <4300378.sBT9DdB2Gc@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20160211180032.GY10826@n2100.arm.linux.org.uk> References: <20151207223534.GA13722@www.outflux.net> <20160211180032.GY10826@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:nQhKSqgaQxUrRZ0Ynf5O5Mv/jdcjzJDDd3ORuS56xMQTETc4K55 kZpSRtBbpgzFeU1xP/YDzQk74mZQaGs70mei9NwQxPrBEF13SPAKY2aDt/2S73cgKkW78LC 1H6ty51hNjVxG+9QfOBlHZk8JEPSUpj90ydfxnNay1mKTfVI6eINSjFqqsJY0SagPrS83Kj X5KZ+uMG2WKIy7qMPvRUg== X-UI-Out-Filterresults: notjunk:1;V01:K0:cG0T5/0Gad4=:vk9Vax44vk5Yb3u85wImVx 8FQXg/iFGAzj296ycP/jNpCwrfO1e1zKHdsC8C5qkVp2lfqNocUqV/9NxJWi7sci6xvnuVetH C7FSqSL/KDbdLXJ8HOgUElD0/cMxbZ1w5xAuPhBeMBT4nwbN8/axSwcESL3Kr6JQgMhhz1bml 9Bbj4lp0NE4EANyXQ/Ygp10QiVW5PQH9UHmN8zjQu8ck66+H6pogkc2CbLXCXXPX60EhbJ5nX n6wT5xQzvur78UTWvm+GhoZglOuz6eXUowFRQ6TSezIumgsBQOMQRdL1j33qJKtIjf3/oX/Qx bwGd4uKeb3hFkIAzlY2+NIXo23JRfd3Fr9iq88FWgHWtfKHiI+Z9UsyPLqA493yHOZZG1srex uob5dI49df7bn19gHN0AtiRyCQ7sVH0GJlmqcGQtyRF2ZzU4+kmfwmN3oFWcl8c7qjtBLy7Rv WrsHDbzCnog7KMlR3oMWxVQAO3E0gaVztPDbcYrp5YAWgq2zDj2Cr+T7zdcqijoBWqqC+nbgK CgqrWkBj+fYBAFubzb+30salNjs12NfJH37DVUCU78LW4K2bQNPJz6FM2OdnlYGscd7PQ1p9Y m3Gw4HJPO305e+GehBLwSm2X4hzyKUvbrhq9kV215tPib5k34MWHKaANlivXrpj3d1rfhKYLx wvd2ac6tVDHTnjbJFtI3vZDkWfnUcY9HtsSIRCb+g+H6C20AQyyCRbXW7Q1QFasgPWPf6huO0 Malp/mY+95U7FI+g Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 11 February 2016 18:00:32 Russell King - ARM Linux wrote: > On Fri, Jan 22, 2016 at 01:19:03PM -0800, Kees Cook wrote: > > On Tue, Dec 8, 2015 at 10:38 AM, Kees Cook wrote: > > > On Mon, Dec 7, 2015 at 11:47 PM, Ard Biesheuvel > > > wrote: > > >> On 7 December 2015 at 23:35, Kees Cook wrote: > > >>> /* > > >>> + * Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will > > >>> + * be the first section-aligned location after __start_rodata. Otherwise, > > >>> + * it will be equal to __start_rodata. > > >>> + */ > > >>> +__start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT); > ... > > I'm afraid this causes build errors on two configurations: > > ./arch/arm/kernel/vmlinux.lds:701: undefined symbol `SECTION_SHIFT' referenced in expression > > which I think is down to the new __start_rodata_section_aligned line. > > Olof's builder errored out with this for both allnoconfig and > lpc18xx_defconfig builds. Both probably due to CONFIG_MMU being > unset, and hence no definition for SECTION_SHIFT. > > I think you need to make this conditional on CONFIG_MMU. I've hit another problem with this patch, when using XIP_KERNEL, I now see arch/arm/mm/built-in.o:(.data+0x4bc): undefined reference to `__start_rodata_section_aligned' in linux-next, apparently because of the combination with "ARM: 8513/1: xip: Move XIP linking to a separate file". Arnd