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Re: Serious bug in uaccess.h

To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Subject: Re: Serious bug in uaccess.h
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Wed, 28 Feb 2001 13:56:28 +0100
Cc: Fabrice Bellard <bellard@email.enst.fr>, linux-mips@oss.sgi.com
In-reply-to: <Pine.GSO.3.96.1010228130945.6646A-100000@delta.ds2.pg.gda.pl>; from macro@ds2.pg.gda.pl on Wed, Feb 28, 2001 at 01:47:27PM +0100
References: <20010227232227.B384@email.enst.fr> <Pine.GSO.3.96.1010228130945.6646A-100000@delta.ds2.pg.gda.pl>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5i
On Wed, Feb 28, 2001 at 01:47:27PM +0100, Maciej W. Rozycki wrote:
> Date: Wed, 28 Feb 2001 13:47:27 +0100 (MET)
> From: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
> To: Fabrice Bellard <bellard@email.enst.fr>,
>         Ralf Baechle <ralf@uni-koblenz.de>
> cc: linux-mips@oss.sgi.com
> Subject: Re: Serious bug in uaccess.h
> 
> On Tue, 27 Feb 2001, Fabrice Bellard wrote:
> 
> > I mean the code in arch/mips/lib/memcpy.S. It is possible to modify
> > __copy_user so that it has exactly the same calling convention of a C
> > function. Then, no asm is necessary in uaccess.h. It costs us a
> > supplementary jump.
> 
>  You mean the supplementary return value in a2?  Hmm, it is always set to
> zero!  Also "addu $1, %2, %3" makes no sense.
> 
>  Ralf, the code is weird.  The header implies you are the author.  Could
> you please elaborate what you meant in copy_*_user()? 

I'll look at it and try to recall :-)

  Ralf

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