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    SubjectRe: [PATCH] x86: Construct 32 bit boot time page tables in native format.
    On Thu 2008-01-24 16:27:58, H. Peter Anvin wrote:
    > Pavel Machek wrote:
    > >>>
    > >>I just looked at the ACPI suspend code, and it looks
    > >>like it hacks its own identity map at runtime. Pavel,
    > >>am I reading that code right?
    > >
    > >Yes, I think so, I believe we do it on both 32 and 64
    > >bit now.
    > >
    >
    > So the background to this... we need an identity map to
    > trampoline at early boot, obviously, but we'd like it to
    > not stick around more than necessary. We have
    > zap_low_mappings() now but it's not really sufficient.
    >
    > Secondary SMP processors need these mappings during
    > trampolining -- presumably including CPU hotplug -- and
    > I'm suspecting it might simply make sense to use a
    > separate set of page tables (with both the identity and
    > the kernel map) for trampolining and just keep them
    > around. That way they would be usable for ACPI as well.

    That would enable some cleanups, yes.
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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