On Fri, Jul 06, 2018 at 05:21:00PM +0100, Mark Rutland wrote: > Please don't open-code this. Use of_device_is_available(), which checks > the status property itself. e.g. > > void __init setup_smp(void) > { > struct device_node *node = NULL; > > while ((node = of_find_node_by_type(node, "cpu"))) { > if (!of_device_is_available(node)) > continue; > > ... > } > } Ok, approve. > Please use the reg property, you need it to describe which particular > CPUs are available. > > You probably also want a mapping from Linux logical CPU id to your > physical CPU id, and a sanity check on this. See arm64 for an example. Yes, you are right. Reg property could determine which bit of CPU in cr<0, 29> could be booted. Thx for the tips. Guo Ren