From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761753AbcLRXlH (ORCPT ); Sun, 18 Dec 2016 18:41:07 -0500 Received: from pandora.armlinux.org.uk ([78.32.30.218]:36934 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752795AbcLRXlF (ORCPT ); Sun, 18 Dec 2016 18:41:05 -0500 Date: Sun, 18 Dec 2016 23:40:53 +0000 From: Russell King - ARM Linux To: Ard Biesheuvel Cc: Arnd Bergmann , Nicolas Pitre , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Jonas Jensen Subject: Re: [PATCH] ARM: disallow ARM_THUMB for ARMv4 builds Message-ID: <20161218234053.GQ14217@n2100.armlinux.org.uk> References: <20161216091457.2452987-1-arnd@arndb.de> <4112999.Nl7pxYH1YF@wuerfel> <20161218141630.GP14217@n2100.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Sun, Dec 18, 2016 at 03:04:24PM +0000, Ard Biesheuvel wrote: > The only issue I spotted is that the kuser_get_tls routine has only > two instruction slots for the return sequence, but we can easily work > around that by moving the TLS hardware instruction around in the > template (and update the memcpy accordingly in kuser_init() You can't actually - everything in this page is ABI, and moving that breaks the ABI. One thing I'm toying with is splitting out the kuser helpers. That means we can build it according to the configuration, and select the appropriate version at run time. Work in progress. -- 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.