On Wed, Jun 29, 2011 at 11:31:39AM -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.
Fix this by always calling platform_smp_prepare_cpus() as long as
max_cpus is non-zero (0 means no SMP) to allow platform code to
decide if any non-boot cpus are present in the system. Since
all current platform code doesn't support physical hotplug we
have a situation where possible == present and thus we can
simply copy the possible map to the present map.

With 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 works with maxcpus=1
on the command line.

Signed-off-by: Stephen Boyd <redacted>

Acked-by: Paul Mundt <redacted>