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Date: Wed, 03 Feb 2010 09:13:09 -0800 (PST)
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Subject: Re: [PATCH 4/6] improve sys_personality for compat architectures
From: David Miller <davem@davemloft.net>
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From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 3 Feb 2010 18:06:27 +0100

>> But if the consensus is that we should fix this properly I can
>> replace the patch with one introducing a compat_sys_personality
>> which only gets used for compat tasks.
> 
> Right now, sparc64 and powerpc64 use sys32_personality for both native
> and compat tasks, x86 never uses it and all others use it only for
> compat tasks. That seems more sensible if we keep this function at
> all.

If it only gets used for compat tasks, you can only switch in
one direction.  I think it needs to be handled for both compat
and non-compat tasks, in order to allow for that.

That's why powerpc64 and sparc64 do things the way they do,
I am pretty sure.