From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian.Campbell@citrix.com (Ian Campbell) Date: Wed, 29 Feb 2012 09:56:02 +0000 Subject: [PATCH-WIP 01/13] xen/arm: use r12 to pass the hypercall number to the hypervisor 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> Message-ID: <1330509362.4270.20.camel@zakaz.uk.xensource.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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.