1/*
2 * Access to user system call parameters and results
3 *
4 * Copyright (C) 2008 Imagination Technologies Ltd.
5 *
6 * This copyrighted material is made available to anyone wishing to use,
7 * modify, copy, or redistribute it subject to the terms and conditions
8 * of the GNU General Public License v.2.
9 *
10 * See asm-generic/syscall.h for descriptions of what we must do here.
11 */
12
13#ifndef _ASM_METAG_SYSCALL_H
14#define _ASM_METAG_SYSCALL_H
15
16#include <linux/sched.h>
17#include <linux/err.h>
18#include <linux/uaccess.h>
19
20#include <asm/switch.h>
21
22static inline long syscall_get_nr(struct task_struct *task,
23				  struct pt_regs *regs)
24{
25	unsigned long insn;
26
27	/*
28	 * FIXME there's no way to find out how we got here other than to
29	 * examine the memory at the PC to see if it is a syscall
30	 * SWITCH instruction.
31	 */
32	if (get_user(insn, (unsigned long *)(regs->ctx.CurrPC - 4)))
33		return -1;
34
35	if (insn == __METAG_SW_ENCODING(SYS))
36		return regs->ctx.DX[0].U1;
37	else
38		return -1L;
39}
40
41static inline void syscall_rollback(struct task_struct *task,
42				    struct pt_regs *regs)
43{
44	/* do nothing */
45}
46
47static inline long syscall_get_error(struct task_struct *task,
48				     struct pt_regs *regs)
49{
50	unsigned long error = regs->ctx.DX[0].U0;
51	return IS_ERR_VALUE(error) ? error : 0;
52}
53
54static inline long syscall_get_return_value(struct task_struct *task,
55					    struct pt_regs *regs)
56{
57	return regs->ctx.DX[0].U0;
58}
59
60static inline void syscall_set_return_value(struct task_struct *task,
61					    struct pt_regs *regs,
62					    int error, long val)
63{
64	regs->ctx.DX[0].U0 = (long) error ?: val;
65}
66
67static inline void syscall_get_arguments(struct task_struct *task,
68					 struct pt_regs *regs,
69					 unsigned int i, unsigned int n,
70					 unsigned long *args)
71{
72	unsigned int reg, j;
73	BUG_ON(i + n > 6);
74
75	for (j = i, reg = 6 - i; j < (i + n); j++, reg--) {
76		if (reg % 2)
77			args[j] = regs->ctx.DX[(reg + 1) / 2].U0;
78		else
79			args[j] = regs->ctx.DX[reg / 2].U1;
80	}
81}
82
83static inline void syscall_set_arguments(struct task_struct *task,
84					 struct pt_regs *regs,
85					 unsigned int i, unsigned int n,
86					 const unsigned long *args)
87{
88	unsigned int reg;
89	BUG_ON(i + n > 6);
90
91	for (reg = 6 - i; i < (i + n); i++, reg--) {
92		if (reg % 2)
93			regs->ctx.DX[(reg + 1) / 2].U0 = args[i];
94		else
95			regs->ctx.DX[reg / 2].U1 = args[i];
96	}
97}
98
99#define NR_syscalls __NR_syscalls
100
101/* generic syscall table */
102extern const void *sys_call_table[];
103
104#endif	/* _ASM_METAG_SYSCALL_H */
105