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Date: Wed, 22 Jan 2003 12:45:40 -0500
From: Christoph Hellwig <hch@sgi.com>
To: Andrew Clausen <clausen@melbourne.sgi.com>
Cc: linux-mips@linux-mips.org, gnb@melbourne.sgi.com
Subject: Re: debian's mips userland on mips64
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On Wed, Jan 22, 2003 at 06:30:06PM +1100, Andrew Clausen wrote:
> Hi all,
> 
> I'm playing with Debian on an Origin 200 (aka ip27 - 64-bit mips).
> The current setup in the mips64-linux world is 64bit kernel +
> 32bit userland.  So, a mips64-linux kernel can be mostly run a
> mips32-linux userland out of the box.
> 
> Unfortunately, this doesn't apply to strace, as this play with
> the 64bit kernel's stack (eg: struct pt_regs), which is different in
> mips32 and mips64.
> 
> So, I guess the solution is to hack (it's ugly as hell already...)
> strace to detect and understand the 64 bit stack from a 32 bit
> userland?

I don't think so.  You should rather implement a sys32_ptrace and
reference it in the 32bit syscall vector.  Look at the version in
arch/ia64/ia32/sys_ia32.c for an example.