s3-lpm.c:838: error: implicit declaration of function 'get_hard_smp_processor_id' This fixes it. We have to include rather than because the UP definition of get_hard_smp_processor_id() is in , and only includes if CONFIG_SMP = y. Signed-off-by: Alexey Dobriyan Acked-by: Geoff Levand Signed-off-by: Paul Mackerras ]Ð '”0x