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
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)20 static inline int syscall_get_nr(struct task_struct *task,
21 struct pt_regs *regs)
22 {
23 return regs->syscallno;
24 }
25
syscall_rollback(struct task_struct * task,struct pt_regs * regs)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
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)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
syscall_get_error(struct task_struct * task,struct pt_regs * regs)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
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)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
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)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
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,const unsigned long * args)76 static inline void syscall_set_arguments(struct task_struct *task,
77 struct pt_regs *regs,
78 const unsigned long *args)
79 {
80 regs->orig_x0 = args[0];
81 args++;
82
83 memcpy(®s->regs[1], args, 5 * sizeof(args[0]));
84 }
85
86 /*
87 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
88 * AArch64 has the same system calls both on little- and big- endian.
89 */
syscall_get_arch(struct task_struct * task)90 static inline int syscall_get_arch(struct task_struct *task)
91 {
92 if (is_compat_thread(task_thread_info(task)))
93 return AUDIT_ARCH_ARM;
94
95 return AUDIT_ARCH_AARCH64;
96 }
97
98 #endif /* __ASM_SYSCALL_H */
99