linux-kernel - Re: how to tell linux (on x86) to ignore 1M or memory

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Message-ID: <46290DED.80500@gmail.com>
Date:	Fri, 20 Apr 2007 21:01:01 +0200
From:	Rene Herman <rene.herman@...il.com>
To:	Bart Trojanowski <bart@...ie.net>
CC:	linux-kernel@...r.kernel.org
Subject: Re: how to tell linux (on x86) to ignore 1M or memory

On 04/19/2007 04:18 PM, Bart Trojanowski wrote:

> I need to preserve some state from the bios before entering protected 
> mode.  For now I want to copy it into some ram accessible by real-mode, 
> say the last megabyte visible in real-mode.
> 
> What's the easiest way to have linux ignore the megabyte starting at 15M?

Note that real-mode can only access the first megabyte (*) and not the first 
16. 16MB is the 16-bit protected mode (286) limit.

(*) well, the first 1M + 64K - 16 bytes using segment FFFF assuming A20 is 
enabled and x > 1 in x86...

Rene.
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