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

[Arjan van de Ven]

On Tue, 2005-11-15 at 11:19 -0500, Dave Jones wrote:
> 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.

the good news is that all hotplugable x86 cpus will have HT or dual core
support.. so you always work in pairs of 2


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