linux-kernel - Re: how to use TLB to prevent Linux accessing a particular memory region

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Message-ID: <754003.20445.qm@web35709.mail.mud.yahoo.com>
Date:	Fri, 19 Oct 2007 17:27:37 -0700 (PDT)
From:	Jim Brooks <jbrooks3d@...oo.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: how to use TLB to prevent Linux accessing a particular memory region

> Out of 32MB of DDR 8MB is reserved for use by DSP
> processor. But the MIPS processor downloads firmware
> into this reserved memory for the DSP.
>
> Now, is it possible to use the TLB to prevent Linux
> from accessing the reserved memory after the
firmware
> has been downloaded?

Well, even if you did remap PTEs (TLBs are N/A),
or claimed that special memory, that may be too late.
The kernel might've already allocated
and stomped over it.

A reliable way is to redefine the kernel's "memory
map"
which takes effect during boot.
Look for the memory map as a .h in arch/ (IIRC).

--
Jim Brooks

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