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Date: Tue, 13 May 2003 18:11:52 +0100
From: Ladislav Michl <ladis@linux-mips.org>
To: Jun Sun <jsun@mvista.com>
Cc: linux-mips@linux-mips.org
Subject: Re: memory for exception vectors
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On Tue, May 13, 2003 at 09:52:44AM -0700, Jun Sun wrote:
[snip]
> I figured that out a while back.  I think you can find answers in
> arch/mips/kernel/setup.c, 
> 
> 	start_pfn = PFN_UP(__pa(&_end));

Strange I read that file many times, but for yet unknown reason never noticed
__pa(&_end). That's what I call selective blindness :)

> I think zero pages are allocated so that all future read-only zero-filled
> pages can be mapped to them.  They are allocated at the beginning of
> start_pfn, which is also after kernel image.

Thanks a lot for explanation, now I'm sure that MC based memory probing for
IP22 will not break anything. Patch will come tomorrow.

	Ladis