Re: [PATCH 1/10] Cr4 is valid on some 486s

From: Dave Jones
Date: Tue Nov 15 2005 - 11:19:57 EST


On Tue, Nov 15, 2005 at 08:14:29AM -0800, H. Peter Anvin wrote:
> Dave Jones wrote:
> >On Tue, Nov 15, 2005 at 05:06:03PM +0100, Arjan van de Ven wrote:
> >
> > > > You still need to preserve the originals so that you can patch in
> > both > > directions.
> > >
> > > why do you insist on both directions? That still sounds like real
> > > overkill to me.
> >
> >cpu hotplug going from UP to SMP ? :)
> >
>
> If you have CPU hotplug enabled, you can run SMP code!

Sure, but if you boot with 1 CPU, spinlocks get nop'd to emulate UP,
and on a 'installed a new cpu' hotplug event, they all come back.

Dave

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