Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753694Ab3DVPS6 (ORCPT ); Mon, 22 Apr 2013 11:18:58 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:62596 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753263Ab3DVPSz (ORCPT ); Mon, 22 Apr 2013 11:18:55 -0400 Date: Mon, 22 Apr 2013 16:18:37 +0100 From: Will Deacon To: Russell King - ARM Linux Cc: =?iso-8859-1?Q?Andr=E9?= Hentschel , "linux-arch@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "gregkh@linuxfoundation.org" Subject: Re: [PATCHv2] arm: Preserve TPIDRURW on context switch Message-ID: <20130422151836.GA15665@mudshark.cambridge.arm.com> References: <517168BB.3070903@dawncrow.de> <20130422143616.GP14496@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20130422143616.GP14496@n2100.arm.linux.org.uk> 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 Content-Length: 1282 Lines: 27 On Mon, Apr 22, 2013 at 03:36:16PM +0100, Russell King - ARM Linux wrote: > On Fri, Apr 19, 2013 at 05:54:35PM +0200, Andr? Hentschel wrote: > > From: =?UTF-8?q?Andr=C3=A9=20Hentschel?= > > > > There are more and more applications coming to WinRT, Wine could support them, > > but mostly they expect to have the thread environment block (TEB) in TPIDRURW. > > This register must be preserved per thread instead of being cleared. > > > > Signed-off-by: Andr? Hentschel > > This actually makes things less efficient all round, because you > now use the value immediately after loading, which means it will cause > pipeline stalls, certainly on older CPUs. > > Could you please rework the patch to try avoiding soo many modifications > to the way things have been done here? copy_thread also needs updating so that the *register* value for the parent is copied to the child, since the parent may have written the register after the last context-switch, meaning that tp_value is out-of-date. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/