Re: [Xen-devel] [PATCH v2 5/5] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

[Catalin Marinas <catalin.marinas@arm.com>]

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