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 23:02:50 +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>
References: <1201167544.30671.64.camel@cthulhu.hellion.org.uk> <200801282150.15411.rjw@sisk.pl> <479E4918.3010204@zytor.com>
In-Reply-To: <479E4918.3010204@zytor.com>
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On Monday, 28 of January 2008, H. Peter Anvin wrote:
> Rafael J. Wysocki wrote:
> > On Monday, 28 of January 2008, Jeremy Fitzhardinge wrote:
> >> Rafael J. Wysocki wrote:
> >>> Actually, no.  We only do that with the kernel code mapping which should be
> >>> safe as long as TLBs are not flushed (and they aren't).
> >>>   
> >> Er, what?  Assuming the TLB will retain some mappings while you 
> >> overwrite the pagetable is a highly dubious prospect.  Are you copying 
> >> the same values over, or something else?
> > 
> > As long as a relocatable kernel is not used to restore a non-relocatable one
> > (or vice versa), we're copying the same values over.
> > 
> 
> So that case is deliberately considered broken?

Not deliberately, but the fix I had caused a regression.  It's just a pending
issue.

Rafael
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