From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756591Ab0BOWSt (ORCPT ); Mon, 15 Feb 2010 17:18:49 -0500 Received: from terminus.zytor.com ([198.137.202.10]:50540 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756445Ab0BOWSs (ORCPT ); Mon, 15 Feb 2010 17:18:48 -0500 Message-ID: <4B79C775.1050903@zytor.com> Date: Mon, 15 Feb 2010 14:15:17 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: Pavel Machek , paulus@samba.org, linuxppc-dev@ozlabs.org, kernel list , Segher Boessenkool , bergner@vnet.ibm.com Subject: Re: register long sp asm("r1") incorrect References: <20100209152444.GA30176@atrey.karlin.mff.cuni.cz> <1265866273.16346.34.camel@pasglop> <20100215073405.GB20456@atrey.karlin.mff.cuni.cz> <1266263992.16346.125.camel@pasglop> <20100215202854.GA21601@elf.ucw.cz> <1266267898.16346.135.camel@pasglop> In-Reply-To: <1266267898.16346.135.camel@pasglop> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/15/2010 01:04 PM, Benjamin Herrenschmidt wrote: > > It's true that most other use of it we have are global scope (local_paca > in r13, glibc use of r2/r13, etc...) afaik, but since r1 itself is the > stack pointer always, I think they pretty much guarantee it works. > It should work, because r1, being the stack pointer, is already marked a reserved register in gcc. The reference Pavel is citing bascially states that gcc won't globally reserve the register, which is true, but it is already reserved anyway. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.