include/asm-x86/smp_64.h

#ifndef __ASM_SMP_H
#define __ASM_SMP_H

extern cpumask_t cpu_initialized;
extern cpumask_t cpu_callin_map;

extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
				  void *info, int wait);

#ifdef CONFIG_SMP

#define raw_smp_processor_id()	read_pda(cpunumber)

#define stack_smp_processor_id()					\
({									\
	struct thread_info *ti;						\
	asm("andq %%rsp,%0; ":"=r" (ti) : "0" (CURRENT_MASK));	\
	ti->cpu;							\
})

/*
 * On x86 all CPUs are mapped 1:1 to the APIC space. This simplifies
 * scheduling and IPI sending and compresses data structures.
 */
static inline int num_booting_cpus(void)
{
	return cpus_weight(cpu_callout_map);
}

#else /* CONFIG_SMP */
#define stack_smp_processor_id() 0

#endif /* !CONFIG_SMP */

#define safe_smp_processor_id()		smp_processor_id()

#endif