syscall.h revision a8031d2ce15bdb90baeae02d7a231ccece73da8b 
1/*
2 * Access to user system call parameters and results
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License.  See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * See asm-generic/syscall.h for descriptions of what we must do here.
9 *
10 * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
11 */
12
13#ifndef __ASM_MIPS_SYSCALL_H
14#define __ASM_MIPS_SYSCALL_H
15
16#include <linux/compiler.h>
17#include <linux/audit.h>
18#include <linux/elf-em.h>
19#include <linux/kernel.h>
20#include <linux/sched.h>
21#include <linux/uaccess.h>
22#include <asm/ptrace.h>
23
24static inline long syscall_get_nr(struct task_struct *task,
25				  struct pt_regs *regs)
26{
27	return regs->regs[2];
28}
29
30static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
31	struct task_struct *task, struct pt_regs *regs, unsigned int n)
32{
33	unsigned long usp __maybe_unused = regs->regs[29];
34
35	switch (n) {
36	case 0: case 1: case 2: case 3:
37		*arg = regs->regs[4 + n];
38
39		return 0;
40
41#ifdef CONFIG_32BIT
42	case 4: case 5: case 6: case 7:
43		return get_user(*arg, (int *)usp + 4 * n);
44#endif
45
46#ifdef CONFIG_64BIT
47	case 4: case 5: case 6: case 7:
48#ifdef CONFIG_MIPS32_O32
49		if (test_thread_flag(TIF_32BIT_REGS))
50			return get_user(*arg, (int *)usp + 4 * n);
51		else
52#endif
53			*arg = regs->regs[4 + n];
54
55		return 0;
56#endif
57
58	default:
59		BUG();
60	}
61
62	unreachable();
63}
64
65static inline long syscall_get_return_value(struct task_struct *task,
66					    struct pt_regs *regs)
67{
68	return regs->regs[2];
69}
70
71static inline void syscall_set_return_value(struct task_struct *task,
72					    struct pt_regs *regs,
73					    int error, long val)
74{
75	if (error) {
76		regs->regs[2] = -error;
77		regs->regs[7] = -1;
78	} else {
79		regs->regs[2] = val;
80		regs->regs[7] = 0;
81	}
82}
83
84static inline void syscall_get_arguments(struct task_struct *task,
85					 struct pt_regs *regs,
86					 unsigned int i, unsigned int n,
87					 unsigned long *args)
88{
89	int ret;
90
91	while (n--)
92		ret |= mips_get_syscall_arg(args++, task, regs, i++);
93
94	/*
95	 * No way to communicate an error because this is a void function.
96	 */
97#if 0
98	return ret;
99#endif
100}
101
102extern const unsigned long sys_call_table[];
103extern const unsigned long sys32_call_table[];
104extern const unsigned long sysn32_call_table[];
105
106static inline int __syscall_get_arch(void)
107{
108	int arch = EM_MIPS;
109#ifdef CONFIG_64BIT
110	arch |=  __AUDIT_ARCH_64BIT;
111#endif
112#if defined(__LITTLE_ENDIAN)
113	arch |=  __AUDIT_ARCH_LE;
114#endif
115	return arch;
116}
117
118#endif	/* __ASM_MIPS_SYSCALL_H */
119