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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86: Construct 32 bit boot time page tables in native format.
Date: Mon, 28 Jan 2008 21:28:55 +0100
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Cc: Jeremy Fitzhardinge <jeremy@goop.org>, Pavel Machek <pavel@ucw.cz>,
       Ingo Molnar <mingo@elte.hu>, Ian Campbell <ijc@hellion.org.uk>,
       Mika =?iso-8859-1?q?Penttil=E4?= <mika.penttila@kolumbus.fi>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@redhat.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>
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On Monday, 28 of January 2008, H. Peter Anvin wrote:
> Jeremy Fitzhardinge wrote:
> > H. Peter Anvin wrote:
> >>  and we already have to have code to synchronize the PGDs on !PAE and 
> >> the PMDs on Xen (although that was supposedly getting fixed).
> > 
> > No, I don't have any plans there.  Xen will continue to require 
> > non-shared kernel pmd, at least for a 32-bit host.  I think the point is 
> > that nothing that requires an identity mapping will work under Xen 
> > anyway, so Xen just doesn't care about this case.
> > 
> 
> Still makes it a special case, not just for this.

In fact swsusp creates its own temporary page tables for restoring the last
part of the image.  Please have a look at
arch/x86/kernel/suspend_*_64.c and the files in arch/x86/power (most
importantly suspend.c).

Thanks,
Rafael