1/*
2 * Copyright (C) 2012 ARM Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
15 */
16#ifndef __ASM_SYSCALL_H
17#define __ASM_SYSCALL_H
18
19#include <uapi/linux/audit.h>
20#include <linux/compat.h>
21#include <linux/err.h>
22
23extern const void *sys_call_table[];
24
25static inline int syscall_get_nr(struct task_struct *task,
26				 struct pt_regs *regs)
27{
28	return regs->syscallno;
29}
30
31static inline void syscall_rollback(struct task_struct *task,
32				    struct pt_regs *regs)
33{
34	regs->regs[0] = regs->orig_x0;
35}
36
37
38static inline long syscall_get_error(struct task_struct *task,
39				     struct pt_regs *regs)
40{
41	unsigned long error = regs->regs[0];
42	return IS_ERR_VALUE(error) ? error : 0;
43}
44
45static inline long syscall_get_return_value(struct task_struct *task,
46					    struct pt_regs *regs)
47{
48	return regs->regs[0];
49}
50
51static inline void syscall_set_return_value(struct task_struct *task,
52					    struct pt_regs *regs,
53					    int error, long val)
54{
55	regs->regs[0] = (long) error ? error : val;
56}
57
58#define SYSCALL_MAX_ARGS 6
59
60static inline void syscall_get_arguments(struct task_struct *task,
61					 struct pt_regs *regs,
62					 unsigned int i, unsigned int n,
63					 unsigned long *args)
64{
65	if (n == 0)
66		return;
67
68	if (i + n > SYSCALL_MAX_ARGS) {
69		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
70		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
71		pr_warning("%s called with max args %d, handling only %d\n",
72			   __func__, i + n, SYSCALL_MAX_ARGS);
73		memset(args_bad, 0, n_bad * sizeof(args[0]));
74	}
75
76	if (i == 0) {
77		args[0] = regs->orig_x0;
78		args++;
79		i++;
80		n--;
81	}
82
83	memcpy(args, &regs->regs[i], n * sizeof(args[0]));
84}
85
86static inline void syscall_set_arguments(struct task_struct *task,
87					 struct pt_regs *regs,
88					 unsigned int i, unsigned int n,
89					 const unsigned long *args)
90{
91	if (n == 0)
92		return;
93
94	if (i + n > SYSCALL_MAX_ARGS) {
95		pr_warning("%s called with max args %d, handling only %d\n",
96			   __func__, i + n, SYSCALL_MAX_ARGS);
97		n = SYSCALL_MAX_ARGS - i;
98	}
99
100	if (i == 0) {
101		regs->orig_x0 = args[0];
102		args++;
103		i++;
104		n--;
105	}
106
107	memcpy(&regs->regs[i], args, n * sizeof(args[0]));
108}
109
110/*
111 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
112 * AArch64 has the same system calls both on little- and big- endian.
113 */
114static inline int syscall_get_arch(void)
115{
116	if (is_compat_task())
117		return AUDIT_ARCH_ARM;
118
119	return AUDIT_ARCH_AARCH64;
120}
121
122#endif	/* __ASM_SYSCALL_H */
123