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
12 typedef long (*syscall_fn_t)(const struct pt_regs *regs);
13
14 extern const syscall_fn_t sys_call_table[];
15
16 #ifdef CONFIG_COMPAT
17 extern const syscall_fn_t compat_sys_call_table[];
18 #endif
19
20 static inline int syscall_get_nr(struct task_struct *task,
21 struct pt_regs *regs)
22 {
23 return regs->syscallno;
24 }
25
26 static inline void syscall_rollback(struct task_struct *task,
27 struct pt_regs *regs)
28 {
29 regs->regs[0] = regs->orig_x0;
30 }
31
32 static 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
43 static 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
51 static 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
64 #define SYSCALL_MAX_ARGS 6
65
66 static inline void syscall_get_arguments(struct task_struct *task,
67 struct pt_regs *regs,
68 unsigned long *args)
69 {
70 args[0] = regs->orig_x0;
71 args++;
72
73 memcpy(args, ®s->regs[1], 5 * sizeof(args[0]));
74 }
75
76 /*
77 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
78 * AArch64 has the same system calls both on little- and big- endian.
79 */
80 static inline int syscall_get_arch(struct task_struct *task)
81 {
82 if (is_compat_thread(task_thread_info(task)))
83 return AUDIT_ARCH_ARM;
84
85 return AUDIT_ARCH_AARCH64;
86 }
87
88 int syscall_trace_enter(struct pt_regs *regs);
89 void syscall_trace_exit(struct pt_regs *regs);
90
91 #endif /* __ASM_SYSCALL_H */
92
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