linux-kernel - Re: [PATCH 1/1] x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct mapping.

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Message-ID: <m2sjmnxsi3.fsf@firstfloor.org>
Date:	Thu, 20 Oct 2011 14:28:20 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	Jacob Shin <jacob.shin@....com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Yinghai Lu <yinghai.lu@...cle.com>,
	Andreas Herrmann <andreas.herrmann3@....com>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] x86: Exclude E820_RESERVED regions and memory holes above 4 GB from direct mapping.

Jacob Shin <jacob.shin@....com> writes:

> On systems with very large memory (1 TB in our case), BIOS may report a
> reserved region or a hole in the E820 map, even above the 4 GB range. Exclude
> these from the direct mapping.

This doesn't make much sense.  Holes above 4GB are completely legal.

If you need to workaround a specific broken BIOS you would need a quirk
only matching that system, with a suitable "BIOS is broken" message.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only
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