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Re: DBE table ordering

To: Keith Owens <kaos@ocs.com.au>
Subject: Re: DBE table ordering
From: "Gleb O. Raiko" <raiko@niisi.msk.ru>
Date: Thu, 18 Apr 2002 13:37:14 +0400
Cc: "'linux-mips@oss.sgi.com'" <linux-mips@oss.sgi.com>
Organization: NIISI RAN
References: <314.1019112700@ocs3.intra.ocs.com.au>
Sender: owner-linux-mips@oss.sgi.com
Keith,

Keith Owens wrote:
> 
> This is a more general problem than mips dbe, other kernel tables and
> other architectures will have the same problem.  I will do a general
> patch against 2.5.8 to sort these tables at init time, and backport the
> general fix to 2.4.19 later.  In the meantime your patch will bypass
> the problem for mips dbe.

Consider it as a feature. It was known from the time Ralf designed it. 

If you really hate this behaviour and want to change it, I guess just
linear serach is OK. Or just introduce set of get/put_dbe{b,w,l}
routines instead of macros and expect just one fault address (well, 6
addresses, if you care). I think, it's better than rearranging the table
on startup (your proposal) and searching in several dbe tables (was
introduced last year).

Another table (in fact, I know only the unaligned access table in
arch/mips*/unaligned.c) is immune, because call from an __init routine
from user space is somewhat tricky and, anyway, isn't allowed.

If you know other tables, I think it's better to find a solution on
individual basis. No needs for a common solution here. 

Regards,
Gleb.

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