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 
32 
syscall_get_error(struct task_struct * task,struct pt_regs * regs)33 static inline long syscall_get_error(struct task_struct *task,
34 				     struct pt_regs *regs)
35 {
36 	unsigned long error = regs->regs[0];
37 
38 	if (is_compat_thread(task_thread_info(task)))
39 		error = sign_extend64(error, 31);
40 
41 	return IS_ERR_VALUE(error) ? error : 0;
42 }
43 
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)44 static inline long syscall_get_return_value(struct task_struct *task,
45 					    struct pt_regs *regs)
46 {
47 	return regs->regs[0];
48 }
49 
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)50 static inline void syscall_set_return_value(struct task_struct *task,
51 					    struct pt_regs *regs,
52 					    int error, long val)
53 {
54 	if (error)
55 		val = error;
56 
57 	if (is_compat_thread(task_thread_info(task)))
58 		val = lower_32_bits(val);
59 
60 	regs->regs[0] = val;
61 }
62 
63 #define SYSCALL_MAX_ARGS 6
64 
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)65 static inline void syscall_get_arguments(struct task_struct *task,
66 					 struct pt_regs *regs,
67 					 unsigned long *args)
68 {
69 	args[0] = regs->orig_x0;
70 	args++;
71 
72 	memcpy(args, &regs->regs[1], 5 * sizeof(args[0]));
73 }
74 
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,const unsigned long * args)75 static inline void syscall_set_arguments(struct task_struct *task,
76 					 struct pt_regs *regs,
77 					 const unsigned long *args)
78 {
79 	regs->orig_x0 = args[0];
80 	args++;
81 
82 	memcpy(&regs->regs[1], args, 5 * sizeof(args[0]));
83 }
84 
85 /*
86  * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
87  * AArch64 has the same system calls both on little- and big- endian.
88  */
syscall_get_arch(struct task_struct * task)89 static inline int syscall_get_arch(struct task_struct *task)
90 {
91 	if (is_compat_thread(task_thread_info(task)))
92 		return AUDIT_ARCH_ARM;
93 
94 	return AUDIT_ARCH_AARCH64;
95 }
96 
97 #endif	/* __ASM_SYSCALL_H */
98