1. 根目录:
2. arch
3. sh
4. include
5. asm
6. syscall_32.h

#ifndef __ASM_SH_SYSCALL_32_H
#define __ASM_SH_SYSCALL_32_H

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <asm/ptrace.h>

/* The system call number is given by the user in R3 */
static inline long syscall_get_nr(struct task_struct *task,
				  struct pt_regs *regs)
{
	return (regs->tra >= 0) ? regs->regs[3] : -1L;
}

static inline void syscall_rollback(struct task_struct *task,
				    struct pt_regs *regs)
{
	/*
	 * XXX: This needs some thought. On SH we don't
	 * save away the original r0 value anywhere.
	 */
}

static inline long syscall_get_error(struct task_struct *task,
				     struct pt_regs *regs)
{
	return IS_ERR_VALUE(regs->regs[0]) ? regs->regs[0] : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
					    struct pt_regs *regs)
{
	return regs->regs[0];
}

static inline void syscall_set_return_value(struct task_struct *task,
					    struct pt_regs *regs,
					    int error, long val)
{
	if (error)
		regs->regs[0] = -error;
	else
		regs->regs[0] = val;
}

static inline void syscall_get_arguments(struct task_struct *task,
					 struct pt_regs *regs,
					 unsigned int i, unsigned int n,
					 unsigned long *args)
{
	/*
	 * Do this simply for now. If we need to start supporting
	 * fetching arguments from arbitrary indices, this will need some
	 * extra logic. Presently there are no in-tree users that depend
	 * on this behaviour.
	 */
	BUG_ON(i);

	/* Argument pattern is: R4, R5, R6, R7, R0, R1 */
	switch (n) {
	case 6: args[5] = regs->regs[1];
	case 5: args[4] = regs->regs[0];
	case 4: args[3] = regs->regs[7];
	case 3: args[2] = regs->regs[6];
	case 2: args[1] = regs->regs[5];
	case 1:	args[0] = regs->regs[4];
	case 0:
		break;
	default:
		BUG();
	}
}

static inline void syscall_set_arguments(struct task_struct *task,
					 struct pt_regs *regs,
					 unsigned int i, unsigned int n,
					 const unsigned long *args)
{
	/* Same note as above applies */
	BUG_ON(i);

	switch (n) {
	case 6: regs->regs[1] = args[5];
	case 5: regs->regs[0] = args[4];
	case 4: regs->regs[7] = args[3];
	case 3: regs->regs[6] = args[2];
	case 2: regs->regs[5] = args[1];
	case 1: regs->regs[4] = args[0];
		break;
	default:
		BUG();
	}
}

#endif /* __ASM_SH_SYSCALL_32_H */