Re: [Xen-devel] [PATCH v4 5/6] arm64/xen: introduce CONFIG_XEN onARM64

From: Ian Campbell
Date: Thu Jun 06 2013 - 05:30:00 EST


On Thu, 2013-06-06 at 10:27 +0100, Catalin Marinas wrote:
> On Thu, Jun 06, 2013 at 10:03:39AM +0100, Ian Campbell wrote:
> > On Wed, 2013-06-05 at 18:02 +0100, Stefano Stabellini wrote:
> > > + * the second in r1/x1, the third in r2/x2 and the fourth in r3/x3.
> > > + * Considering that Xen hypercalls have 5 arguments at most, the fifth
> > > + * paramter is always passed in r4/x4, differently from the ARM
> > > + * procedure calling convention of using the stack for that case.
> >
> > and "parameter" again.
> >
> > Strictly speaking the fifth argument handling only differs from the
> > 32-bit PCS, not the 64-bit one. Splitting hairs a bit there.
>
> I agree, just add "the fifth in x4" without "differently from ...", it's
> not relevant.

Works for me.

> You can also remove references to r? registers, they are only called x?.

This is documenting both the Aarch32 and AArch64 conventions.

Ian.

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