From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 3 Jun 2013 17:43:29 +0100 Subject: [Xen-devel] [PATCH v2 5/5] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64 In-Reply-To: <1370277455.24512.46.camel@zakaz.uk.xensource.com> References: <1370273624-26976-5-git-send-email-stefano.stabellini@eu.citrix.com> <20130603162517.GC32295@arm.com> <1370277455.24512.46.camel@zakaz.uk.xensource.com> Message-ID: <20130603164329.GD32295@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jun 03, 2013 at 05:37:35PM +0100, Ian Campbell wrote: > On Mon, 2013-06-03 at 17:25 +0100, Catalin Marinas wrote: > > On Mon, Jun 03, 2013 at 04:33:44PM +0100, Stefano Stabellini wrote: > > > --- /dev/null > > > +++ b/arch/arm64/xen/hypercall.S > > ... > > > +/* > > > + * The Xen hypercall calling convention is very similar to the ARM AEBI > > > + * procedure calling convention: the first paramter is passed in x0, the > > > + * second in x1, the third in x2 and the fourth in x3. Considering that > > > + * Xen hypercalls have 5 arguments at most, the fifth paramter is passed > > parameter > > > > + * in rx, differently from the procedure calling convention of using the > > ^x4 not rx > > > > + * stack for that case. > > > > You may want to use the AArch64 ABI here where parameters are passed in > > x0-x7, return in x0. > > I think that is actually what we are doing (up to 5 arguments), the > "Considering that ..." bit at the end is a left over of the 32 bit > version I think. Yes, only the comment needs updating. -- Catalin