From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933365AbcHJXCx (ORCPT ); Wed, 10 Aug 2016 19:02:53 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:48202 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932477AbcHJXCw (ORCPT ); Wed, 10 Aug 2016 19:02:52 -0400 Date: Thu, 11 Aug 2016 00:02:42 +0100 From: Russell King - ARM Linux To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, Kees Cook , Ard Biesheuvel , x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Andrew Morton , Mathias Krause Subject: Re: [PATCH 2/2] arm: apply more __ro_after_init Message-ID: <20160810230242.GO1041@n2100.armlinux.org.uk> References: <1464979224-2085-1-git-send-email-keescook@chromium.org> <2342289.4RWg0SWI3A@wuerfel> <20160810101253.GL1041@n2100.armlinux.org.uk> <2096112.OBiRuggdEi@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2096112.OBiRuggdEi@wuerfel> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 10, 2016 at 09:31:05PM +0200, Arnd Bergmann wrote: > On Wednesday, August 10, 2016 11:12:53 AM CEST Russell King - ARM Linux wrote: > > There's the TLS emulation too, but that writes via the vectors mapping > > at 0xffff0ff0. > > Ok, so that should be safe. Can we change the fiq code to also use the > high mapping and then take the __ro_after_init patch on top? We can't - if the kernel is configured without the kuser helpers in the vectors page, it's mapped read-only. I'm not sure what the intersection is between platforms that can have FIQs and platforms that can disable the kuser helpers. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.