From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v2 for 4.5] arm32: fix build after 063188f4b3
Date: Tue, 14 Oct 2014 14:18:03 +0100
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To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel@lists.xenproject.org, Julien Grall <julien.grall@linaro.org>, stefano.stabellini@citrix.com, tim@xen.org
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On Tue, 2014-10-14 at 14:13 +0100, Jan Beulich wrote:
> >>> On 14.10.14 at 15:06, <julien.grall@linaro.org> wrote:
> > On 10/14/2014 01:57 PM, Ian Campbell wrote:
> >> On Tue, 2014-10-14 at 13:43 +0100, Julien Grall wrote:
> >>> On 10/14/2014 10:15 AM, Ian Campbell wrote:
> >>>> On Mon, 2014-10-13 at 16:29 +0100, Julien Grall wrote:
> >>>>> +int do_smc(register_t function_id, ...);
> >>>>
> >>>> Are you sure that the variadic function calling convention is the same
> >>>> as for a regular function call? I'm not entirely clear having read
> >>>> AAPCS, it says they are marshalled according to "the standard base". 
> >>>
> >>> All the parameters fits in a register, so the compiler will effectively
> >>> use the first registers to pass arguments.
> >> 
> >> Does it? Even with variadic functions? It's not unheard of for an ABI to
> >> fallback to pushing things onto the stack for such cases, since it works
> >> out far easier in stdargs.h.
> > 
> > You are right, it looks like it's compiler depend how variadic function
> > will be called.
> 
> Now that should never happen - there ought to be an ABI that all
> compilers abide by.

Agreed.

Ian.