Re: [PATCH] x86: Construct 32 bit boot time page tables in nativeformat.

From: H. Peter Anvin
Date: Thu Jan 24 2008 - 18:12:45 EST


Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Yeah, and it's ugly for the kernel proper, so that bit is a no-brainer. It's just a matter of hammering out the details.

It doesn't sound from the above that you have any opinion either way about reusing the initial page tables or creating a new set, as long as they're in the same format.

Right.

Xen provides a initial set of pagetables in the appropriate format, so what head.S generates is moot. For simplicity I graft the Xen-provided pagetables into swapper_pg_dir in xen_start_kernel, so it is the functional equivalent to the head.S pagetable construction.

We also don't (yet) support PSE, so that's a non-issue for us too.


While we're mucking around in this area, there is another thing which we should eventually get around to fixing:

we need a set of page tables with an identity mapping as well as the kernel mapping, for trampolining (during startup, but also during things like ACPI suspend/resume.) Right now, we let those be the swapper page tables, but that's probably not really a good idea, since it can hide bugs.

-hpa
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