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Date: Sun, 20 Jan 2008 19:55:41 +0100
From: Andi Kleen <andi@firstfloor.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>, Ian Campbell <ijc@hellion.org.uk>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@redhat.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH] x86: Construct 32 bit boot time page tables in native format.
Message-ID: <20080120185541.GA28024@one.firstfloor.org>
References: <1200758937-22386-1-git-send-email-ijc@hellion.org.uk> <1200758937-22386-2-git-send-email-ijc@hellion.org.uk> <87prvxct42.fsf@basil.nowhere.org> <1200847490.26633.62.camel@cthulhu.hellion.org.uk> <20080120173938.GA27247@one.firstfloor.org> <47939787.3050707@zytor.com>
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> >There are various loaders (kexec, elilo, ...) that skip the 16bit code
> >and jump directly to 32bit head.S. So in theory those could hit it.
> >But still having the loop only is probably fine.
> >
> 
> It's probably just as well, since we don't really know how to get a 
> message out in such an environment anyway...

It would be robably possible to extend the 32bit protocol to some
way to error out in such a case. On the other hand I'm not sure it's really
worth the considerable work to implement and debug such an addition.

> >>variant of make_pte now though.
> >
> >The 32bit cast still feels unclean. After all the PTE is not 32bit.
> 
> No, but (pte_t *) is 32 bits.  To be more "Linuxy" it probably should be 
> (long) or (unsigned long) though.

That's not 32bit either.

-Andi