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 <uapi/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#include <asm/unistd.h>
24
25#ifndef __NR_syscall /* Only defined if _MIPS_SIM == _MIPS_SIM_ABI32 */
26#define __NR_syscall 4000
27#endif
28
29static inline long syscall_get_nr(struct task_struct *task,
30				  struct pt_regs *regs)
31{
32	return current_thread_info()->syscall;
33}
34
35static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
36	struct task_struct *task, struct pt_regs *regs, unsigned int n)
37{
38	unsigned long usp __maybe_unused = regs->regs[29];
39
40	switch (n) {
41	case 0: case 1: case 2: case 3:
42		*arg = regs->regs[4 + n];
43
44		return 0;
45
46#ifdef CONFIG_32BIT
47	case 4: case 5: case 6: case 7:
48		return get_user(*arg, (int *)usp + n);
49#endif
50
51#ifdef CONFIG_64BIT
52	case 4: case 5: case 6: case 7:
53#ifdef CONFIG_MIPS32_O32
54		if (test_thread_flag(TIF_32BIT_REGS))
55			return get_user(*arg, (int *)usp + n);
56		else
57#endif
58			*arg = regs->regs[4 + n];
59
60		return 0;
61#endif
62
63	default:
64		BUG();
65	}
66
67	unreachable();
68}
69
70static inline long syscall_get_return_value(struct task_struct *task,
71					    struct pt_regs *regs)
72{
73	return regs->regs[2];
74}
75
76static inline void syscall_rollback(struct task_struct *task,
77				    struct pt_regs *regs)
78{
79	/* Do nothing */
80}
81
82static inline void syscall_set_return_value(struct task_struct *task,
83					    struct pt_regs *regs,
84					    int error, long val)
85{
86	if (error) {
87		regs->regs[2] = -error;
88		regs->regs[7] = -1;
89	} else {
90		regs->regs[2] = val;
91		regs->regs[7] = 0;
92	}
93}
94
95static inline void syscall_get_arguments(struct task_struct *task,
96					 struct pt_regs *regs,
97					 unsigned int i, unsigned int n,
98					 unsigned long *args)
99{
100	int ret;
101	/* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
102	if ((config_enabled(CONFIG_32BIT) ||
103	    test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
104	    (regs->regs[2] == __NR_syscall))
105		i++;
106
107	while (n--)
108		ret |= mips_get_syscall_arg(args++, task, regs, i++);
109
110	/*
111	 * No way to communicate an error because this is a void function.
112	 */
113#if 0
114	return ret;
115#endif
116}
117
118extern const unsigned long sys_call_table[];
119extern const unsigned long sys32_call_table[];
120extern const unsigned long sysn32_call_table[];
121
122static inline int syscall_get_arch(void)
123{
124	int arch = AUDIT_ARCH_MIPS;
125#ifdef CONFIG_64BIT
126	if (!test_thread_flag(TIF_32BIT_REGS)) {
127		arch |= __AUDIT_ARCH_64BIT;
128		/* N32 sets only TIF_32BIT_ADDR */
129		if (test_thread_flag(TIF_32BIT_ADDR))
130			arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
131	}
132#endif
133#if defined(__LITTLE_ENDIAN)
134	arch |=  __AUDIT_ARCH_LE;
135#endif
136	return arch;
137}
138
139#endif	/* __ASM_MIPS_SYSCALL_H */
140