Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030292Ab2B2J4N (ORCPT ); Wed, 29 Feb 2012 04:56:13 -0500 Received: from smtp.eu.citrix.com ([62.200.22.115]:1482 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965547Ab2B2J4I (ORCPT ); Wed, 29 Feb 2012 04:56:08 -0500 X-IronPort-AV: E=Sophos;i="4.73,501,1325462400"; d="scan'208";a="11003525" Message-ID: <1330509362.4270.20.camel@zakaz.uk.xensource.com> Subject: Re: [PATCH-WIP 01/13] xen/arm: use r12 to pass the hypercall number to the hypervisor From: Ian Campbell To: Dave Martin , Peter Maydell CC: Stefano Stabellini , "xen-devel@lists.xensource.com" , "linaro-dev@lists.linaro.org" , "kvm@vger.kernel.org" , "arnd@arndb.de" , "catalin.marinas@arm.com" , "linux-kernel@vger.kernel.org" , David Vrabel , "linux-arm-kernel@lists.infradead.org" Date: Wed, 29 Feb 2012 09:56:02 +0000 In-Reply-To: <20120229093436.GA2077@linaro.org> References: <1330019314-20865-1-git-send-email-stefano.stabellini@eu.citrix.com> <1330360043.8557.302.camel@zakaz.uk.xensource.com> <20120227180355.GB2023@linaro.org> <1330371219.10008.34.camel@dagon.hellion.org.uk> <20120228102040.GB2063@linaro.org> <1330426133.31269.70.camel@zakaz.uk.xensource.com> <20120229093436.GA2077@linaro.org> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 873 Lines: 24 On Wed, 2012-02-29 at 09:34 +0000, Dave Martin wrote: > On Tue, Feb 28, 2012 at 12:28:29PM +0000, Stefano Stabellini wrote: > > I don't have a very strong opinion on which register we should use, but > > I would like to avoid r7 if it is already actively used by gcc. > > But there is no framepointer for Thumb-2 code (?) Peter Maydell suggested there was: > r7 is (used by gcc as) the Thumb frame pointer; I don't know if this > makes it worth avoiding in this context. Sounds like it might be a gcc-ism, possibly a non-default option? Anyway, I think r12 will be fine for our purposes so the point is rather moot. Ian. -- 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/