From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <ak@suse.de>
Subject: Re: 32/64-bit hypercall interface
Date: Tue, 4 Oct 2005 18:45:20 +0200
Message-ID: <200510041845.20902.ak@suse.de>
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To: "Nakajima, Jun" <jun.nakajima@intel.com>
Cc: Jeremy Katz <katzj@redhat.com>, xen-devel@lists.xensource.com, Ian Pratt <Ian.Pratt@cl.cam.ac.uk>
List-Id: xen-devel@lists.xenproject.org

On Tuesday 04 October 2005 18:03, Nakajima, Jun wrote:

>
> I don't think we should use "int N" sacrificing the good feature for
> 64-bit when we can handle 32-bit hypercalls using a compatibility layer.
> I also think using the existing ABI convention is much better whenever
> possible and appropriate because we don't need to re-invent the wheel.
> After all, the only difference between system call and hyper call
> basically is the system/hypercall number.

Main 32bit linux solves this problem by mapping a vsyscall page into the
address space. The ABI is then just to jump to an appropiate entry point in 
it. The entry point uses the right instruction then.
 
-Andi