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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 bool mips_syscall_is_indirect(struct task_struct *task,
30 struct pt_regs *regs)
31{
32 /* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
33 return (IS_ENABLED(CONFIG_32BIT) ||
34 test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
35 (regs->regs[2] == __NR_syscall);
36}
37
38static inline long syscall_get_nr(struct task_struct *task,
39 struct pt_regs *regs)
40{
41 return current_thread_info()->syscall;
42}
43
44static inline void mips_syscall_update_nr(struct task_struct *task,
45 struct pt_regs *regs)
46{
47 /*
48 * v0 is the system call number, except for O32 ABI syscall(), where it
49 * ends up in a0.
50 */
51 if (mips_syscall_is_indirect(task, regs))
52 task_thread_info(task)->syscall = regs->regs[4];
53 else
54 task_thread_info(task)->syscall = regs->regs[2];
55}
56
57static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
58 struct task_struct *task, struct pt_regs *regs, unsigned int n)
59{
60 unsigned long usp __maybe_unused = regs->regs[29];
61
62 switch (n) {
63 case 0: case 1: case 2: case 3:
64 *arg = regs->regs[4 + n];
65
66 return 0;
67
68#ifdef CONFIG_32BIT
69 case 4: case 5: case 6: case 7:
70 return get_user(*arg, (int *)usp + n);
71#endif
72
73#ifdef CONFIG_64BIT
74 case 4: case 5: case 6: case 7:
75#ifdef CONFIG_MIPS32_O32
76 if (test_tsk_thread_flag(task, TIF_32BIT_REGS))
77 return get_user(*arg, (int *)usp + n);
78 else
79#endif
80 *arg = regs->regs[4 + n];
81
82 return 0;
83#endif
84
85 default:
86 BUG();
87 }
88
89 unreachable();
90}
91
92static inline long syscall_get_return_value(struct task_struct *task,
93 struct pt_regs *regs)
94{
95 return regs->regs[2];
96}
97
98static inline void syscall_rollback(struct task_struct *task,
99 struct pt_regs *regs)
100{
101 /* Do nothing */
102}
103
104static inline void syscall_set_return_value(struct task_struct *task,
105 struct pt_regs *regs,
106 int error, long val)
107{
108 if (error) {
109 regs->regs[2] = -error;
110 regs->regs[7] = 1;
111 } else {
112 regs->regs[2] = val;
113 regs->regs[7] = 0;
114 }
115}
116
117static inline void syscall_get_arguments(struct task_struct *task,
118 struct pt_regs *regs,
119 unsigned long *args)
120{
121 unsigned int i = 0;
122 unsigned int n = 6;
123 int ret;
124
125 /* O32 ABI syscall() */
126 if (mips_syscall_is_indirect(task, regs))
127 i++;
128
129 while (n--)
130 ret |= mips_get_syscall_arg(args++, task, regs, i++);
131
132 /*
133 * No way to communicate an error because this is a void function.
134 */
135#if 0
136 return ret;
137#endif
138}
139
140extern const unsigned long sys_call_table[];
141extern const unsigned long sys32_call_table[];
142extern const unsigned long sysn32_call_table[];
143
144static inline int syscall_get_arch(struct task_struct *task)
145{
146 int arch = AUDIT_ARCH_MIPS;
147#ifdef CONFIG_64BIT
148 if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) {
149 arch |= __AUDIT_ARCH_64BIT;
150 /* N32 sets only TIF_32BIT_ADDR */
151 if (test_tsk_thread_flag(task, TIF_32BIT_ADDR))
152 arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
153 }
154#endif
155#if defined(__LITTLE_ENDIAN)
156 arch |= __AUDIT_ARCH_LE;
157#endif
158 return arch;
159}
160
161#endif /* __ASM_MIPS_SYSCALL_H */