1. 根目录:
2. arch
3. score
4. include
5. asm
6. system.h

#ifndef _ASM_SCORE_SYSTEM_H
#define _ASM_SCORE_SYSTEM_H

#include <linux/types.h>
#include <linux/irqflags.h>

struct pt_regs;
struct task_struct;

extern void *resume(void *last, void *next, void *next_ti);

#define switch_to(prev, next, last)				\
do {								\
	(last) = resume(prev, next, task_thread_info(next));	\
} while (0)

#define finish_arch_switch(prev)	do {} while (0)

typedef void (*vi_handler_t)(void);
extern unsigned long arch_align_stack(unsigned long sp);

#define mb()		barrier()
#define rmb()		barrier()
#define wmb()		barrier()
#define smp_mb()	barrier()
#define smp_rmb()	barrier()
#define smp_wmb()	barrier()

#define read_barrier_depends()		do {} while (0)
#define smp_read_barrier_depends()	do {} while (0)

#define set_mb(var, value) 		do {var = value; wmb(); } while (0)

#define __HAVE_ARCH_CMPXCHG	1

#include <asm-generic/cmpxchg-local.h>

#ifndef __ASSEMBLY__

struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))

static inline
unsigned long __xchg(volatile unsigned long *m, unsigned long val)
{
	unsigned long retval;
	unsigned long flags;

	local_irq_save(flags);
	retval = *m;
	*m = val;
	local_irq_restore(flags);
	return retval;
}

#define xchg(ptr, v)						\
	((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr),	\
					(unsigned long)(v)))

static inline unsigned long __cmpxchg(volatile unsigned long *m,
				unsigned long old, unsigned long new)
{
	unsigned long retval;
	unsigned long flags;

	local_irq_save(flags);
	retval = *m;
	if (retval == old)
		*m = new;
	local_irq_restore(flags);
	return retval;
}

#define cmpxchg(ptr, o, n)					\
	((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr),	\
					(unsigned long)(o),	\
					(unsigned long)(n)))

extern void __die(const char *, struct pt_regs *, const char *,
	const char *, unsigned long) __attribute__((noreturn));
extern void __die_if_kernel(const char *, struct pt_regs *, const char *,
	const char *, unsigned long);

#define die(msg, regs)							\
	__die(msg, regs, __FILE__ ":", __func__, __LINE__)
#define die_if_kernel(msg, regs)					\
	__die_if_kernel(msg, regs, __FILE__ ":", __func__, __LINE__)

#endif /* !__ASSEMBLY__ */
#endif /* _ASM_SCORE_SYSTEM_H */