1 /*
2  * Access to user system call parameters and results
3  *
4  * See asm-generic/syscall.h for function descriptions.
5  *
6  * Copyright (C) 2015 Mickaël Salaün <mic@digikod.net>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 
13 #ifndef __UM_SYSCALL_GENERIC_H
14 #define __UM_SYSCALL_GENERIC_H
15 
16 #include <asm/ptrace.h>
17 #include <linux/err.h>
18 #include <linux/sched.h>
19 #include <sysdep/ptrace.h>
20 
21 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
22 {
23 
24 	return PT_REGS_SYSCALL_NR(regs);
25 }
26 
27 static inline void syscall_rollback(struct task_struct *task,
28 				    struct pt_regs *regs)
29 {
30 	/* do nothing */
31 }
32 
33 static inline long syscall_get_error(struct task_struct *task,
34 				     struct pt_regs *regs)
35 {
36 	const long error = regs_return_value(regs);
37 
38 	return IS_ERR_VALUE(error) ? error : 0;
39 }
40 
41 static inline long syscall_get_return_value(struct task_struct *task,
42 					    struct pt_regs *regs)
43 {
44 	return regs_return_value(regs);
45 }
46 
47 static inline void syscall_set_return_value(struct task_struct *task,
48 					    struct pt_regs *regs,
49 					    int error, long val)
50 {
51 	PT_REGS_SET_SYSCALL_RETURN(regs, (long) error ?: val);
52 }
53 
54 static inline void syscall_get_arguments(struct task_struct *task,
55 					 struct pt_regs *regs,
56 					 unsigned int i, unsigned int n,
57 					 unsigned long *args)
58 {
59 	const struct uml_pt_regs *r = &regs->regs;
60 
61 	switch (i) {
62 	case 0:
63 		if (!n--)
64 			break;
65 		*args++ = UPT_SYSCALL_ARG1(r);
66 	case 1:
67 		if (!n--)
68 			break;
69 		*args++ = UPT_SYSCALL_ARG2(r);
70 	case 2:
71 		if (!n--)
72 			break;
73 		*args++ = UPT_SYSCALL_ARG3(r);
74 	case 3:
75 		if (!n--)
76 			break;
77 		*args++ = UPT_SYSCALL_ARG4(r);
78 	case 4:
79 		if (!n--)
80 			break;
81 		*args++ = UPT_SYSCALL_ARG5(r);
82 	case 5:
83 		if (!n--)
84 			break;
85 		*args++ = UPT_SYSCALL_ARG6(r);
86 	case 6:
87 		if (!n--)
88 			break;
89 	default:
90 		BUG();
91 		break;
92 	}
93 }
94 
95 static inline void syscall_set_arguments(struct task_struct *task,
96 					 struct pt_regs *regs,
97 					 unsigned int i, unsigned int n,
98 					 const unsigned long *args)
99 {
100 	struct uml_pt_regs *r = &regs->regs;
101 
102 	switch (i) {
103 	case 0:
104 		if (!n--)
105 			break;
106 		UPT_SYSCALL_ARG1(r) = *args++;
107 	case 1:
108 		if (!n--)
109 			break;
110 		UPT_SYSCALL_ARG2(r) = *args++;
111 	case 2:
112 		if (!n--)
113 			break;
114 		UPT_SYSCALL_ARG3(r) = *args++;
115 	case 3:
116 		if (!n--)
117 			break;
118 		UPT_SYSCALL_ARG4(r) = *args++;
119 	case 4:
120 		if (!n--)
121 			break;
122 		UPT_SYSCALL_ARG5(r) = *args++;
123 	case 5:
124 		if (!n--)
125 			break;
126 		UPT_SYSCALL_ARG6(r) = *args++;
127 	case 6:
128 		if (!n--)
129 			break;
130 	default:
131 		BUG();
132 		break;
133 	}
134 }
135 
136 /* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
137 
138 #endif	/* __UM_SYSCALL_GENERIC_H */
139