[PATCHv2] arm: platsmp: Allow secondary cpu hotplug with maxcpus=1

[Russell King - ARM Linux]

On Tue, Jul 05, 2011 at 10:29:17AM -0700, Stephen Boyd wrote:
> If an ARM system has multiple cpus in the same socket and the
> kernel is booted with maxcpus=1, secondary cpus are possible but
> not present due to how platform_smp_prepare_cpus() is called.
> Since most typical ARM processors don't actually support physical
> hotplug, initialize the present map to be equal to the possible
> map in generic ARM SMP code. Also, always call
> platform_smp_prepare_cpus() as long as max_cpus is non-zero (0
> means no SMP) to allow platform code to do any SMP setup.
> 
> After applying this patch it's possible to boot an ARM system
> with maxcpus=1 on the command line and then hotplug in secondary
> cpus via sysfs. This is more in line with how x86 does things.

Ok - how about putting this in the patch system?

Thanks.