Re: [patch 02/11] PAT x86: Map only usable memory in x86_64 identitymap and kernel text

[Linus Torvalds]

On Thu, 10 Jan 2008, venkatesh.pallipadi@xxxxxxxxx wrote:
>
> x86_64: Map only usable memory in identity map. All reserved memory maps to a
> zero page.

I don't mind this horribly per se, but why a zero page?

Accessing that page without mapping it explicitly would be a bug with 
your change - if only because you'd get the wrong value!

So why map it at all? The only thing mapping it can do is to hide bugs.

			Linus
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