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, &regs->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  */
syscall_get_arch(struct task_struct * task)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 #endif	/* __ASM_SYSCALL_H */
89