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
syscall_set_nr(struct task_struct * task,struct pt_regs * regs,int nr)64 static 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
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)82 static 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
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,const unsigned long * args)92 static 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 */
syscall_get_arch(struct task_struct * task)109 static 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
117 int syscall_trace_enter(struct pt_regs *regs);
118 void syscall_trace_exit(struct pt_regs *regs);
119
120 #endif /* __ASM_SYSCALL_H */
121