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Date: Fri, 25 Jan 2002 11:17:31 -0700
From: Val Henson <val@nmt.edu>
To: "Albert D. Cahalan" <acahalan@cs.uml.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Athlon/AGP issue update
Message-ID: <20020125111731.B26874@boardwalk>
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In-Reply-To: <200201232314.g0NNEXe457847@saturn.cs.uml.edu>; from acahalan@cs.uml.edu on Wed, Jan 23, 2002 at 06:14:33PM -0500
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On Wed, Jan 23, 2002 at 06:14:33PM -0500, Albert D. Cahalan wrote:
> 
> It's a waste to use BAT mappings for the kernel anyway, because
> we try to keep the huge computations and graphics in userspace.
> With page tables under BAT mappings, privileged user code could
> be allowed to steal BAT registers for locked memory or IO memory.

The rationale behind BAT mapping the kernel is that the kernel does not
use any TLB entries, leaving them all for user processes. (As long as
we have < 512MB RAM.)

-VAL
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