Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 */
5#ifndef __ASM_SYSCALL_H
6#define __ASM_SYSCALL_H
7
8#include <uapi/linux/audit.h>
9#include <linux/compat.h>
10#include <linux/err.h>
11
12typedef long (*syscall_fn_t)(const struct pt_regs *regs);
13
14extern const syscall_fn_t sys_call_table[];
15
16#ifdef CONFIG_COMPAT
17extern const syscall_fn_t compat_sys_call_table[];
18#endif
19
20static inline int syscall_get_nr(struct task_struct *task,
21 struct pt_regs *regs)
22{
23 return regs->syscallno;
24}
25
26static inline void syscall_rollback(struct task_struct *task,
27 struct pt_regs *regs)
28{
29 regs->regs[0] = regs->orig_x0;
30}
31
32static inline long syscall_get_return_value(struct task_struct *task,
33 struct pt_regs *regs)
34{
35 unsigned long val = regs->regs[0];
36
37 if (is_compat_thread(task_thread_info(task)))
38 val = sign_extend64(val, 31);
39
40 return val;
41}
42
43static inline long syscall_get_error(struct task_struct *task,
44 struct pt_regs *regs)
45{
46 unsigned long error = syscall_get_return_value(task, regs);
47
48 return IS_ERR_VALUE(error) ? error : 0;
49}
50
51static inline void syscall_set_return_value(struct task_struct *task,
52 struct pt_regs *regs,
53 int error, long val)
54{
55 if (error)
56 val = error;
57
58 if (is_compat_thread(task_thread_info(task)))
59 val = lower_32_bits(val);
60
61 regs->regs[0] = val;
62}
63
64static inline void syscall_set_nr(struct task_struct *task,
65 struct pt_regs *regs,
66 int nr)
67{
68 regs->syscallno = nr;
69 if (nr == -1) {
70 /*
71 * When the syscall number is set to -1, the syscall will be
72 * skipped. In this case the syscall return value has to be
73 * set explicitly, otherwise the first syscall argument is
74 * returned as the syscall return value.
75 */
76 syscall_set_return_value(task, regs, -ENOSYS, 0);
77 }
78}
79
80#define SYSCALL_MAX_ARGS 6
81
82static inline void syscall_get_arguments(struct task_struct *task,
83 struct pt_regs *regs,
84 unsigned long *args)
85{
86 args[0] = regs->orig_x0;
87 args++;
88
89 memcpy(args, ®s->regs[1], 5 * sizeof(args[0]));
90}
91
92static inline void syscall_set_arguments(struct task_struct *task,
93 struct pt_regs *regs,
94 const unsigned long *args)
95{
96 memcpy(®s->regs[0], args, 6 * sizeof(args[0]));
97 /*
98 * Also copy the first argument into orig_x0
99 * so that syscall_get_arguments() would return it
100 * instead of the previous value.
101 */
102 regs->orig_x0 = regs->regs[0];
103}
104
105/*
106 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
107 * AArch64 has the same system calls both on little- and big- endian.
108 */
109static inline int syscall_get_arch(struct task_struct *task)
110{
111 if (is_compat_thread(task_thread_info(task)))
112 return AUDIT_ARCH_ARM;
113
114 return AUDIT_ARCH_AARCH64;
115}
116
117int syscall_trace_enter(struct pt_regs *regs);
118void syscall_trace_exit(struct pt_regs *regs);
119
120#endif /* __ASM_SYSCALL_H */