preempt_disable();
int __init start_secondary(void *unused){	cpu_init();	smp_callin();	while (!cpu_isset(smp_processor_id(), smp_commenced_mask))		cpu_relax();	smp_online();	/*	 * low-memory mappings have been cleared, flush them from	 * the local TLBs too.	 */	local_flush_tlb_all();	cpu_idle();	return 0;}