Linux kernel mirror (for testing)
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1/*
2 * Access to user system call parameters and results
3 *
4 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
5 *
6 * This copyrighted material is made available to anyone wishing to use,
7 * modify, copy, or redistribute it subject to the terms and conditions
8 * of the GNU General Public License v.2.
9 *
10 * See asm-generic/syscall.h for descriptions of what we must do here.
11 */
12
13#ifndef _ASM_SYSCALL_H
14#define _ASM_SYSCALL_H 1
15
16#include <uapi/linux/audit.h>
17#include <linux/sched.h>
18#include <linux/thread_info.h>
19
20/* ftrace syscalls requires exporting the sys_call_table */
21extern const unsigned long sys_call_table[];
22extern const unsigned long compat_sys_call_table[];
23
24static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
25{
26 /*
27 * Note that we are returning an int here. That means 0xffffffff, ie.
28 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
29 * This is important for seccomp so that compat tasks can set r0 = -1
30 * to reject the syscall.
31 */
32 return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1;
33}
34
35static inline void syscall_rollback(struct task_struct *task,
36 struct pt_regs *regs)
37{
38 regs->gpr[3] = regs->orig_gpr3;
39}
40
41static inline long syscall_get_return_value(struct task_struct *task,
42 struct pt_regs *regs)
43{
44 return regs->gpr[3];
45}
46
47static inline void syscall_set_return_value(struct task_struct *task,
48 struct pt_regs *regs,
49 int error, long val)
50{
51 /*
52 * In the general case it's not obvious that we must deal with CCR
53 * here, as the syscall exit path will also do that for us. However
54 * there are some places, eg. the signal code, which check ccr to
55 * decide if the value in r3 is actually an error.
56 */
57 if (error) {
58 regs->ccr |= 0x10000000L;
59 regs->gpr[3] = error;
60 } else {
61 regs->ccr &= ~0x10000000L;
62 regs->gpr[3] = val;
63 }
64}
65
66static inline void syscall_get_arguments(struct task_struct *task,
67 struct pt_regs *regs,
68 unsigned long *args)
69{
70 unsigned long val, mask = -1UL;
71 unsigned int n = 6;
72
73#ifdef CONFIG_COMPAT
74 if (test_tsk_thread_flag(task, TIF_32BIT))
75 mask = 0xffffffff;
76#endif
77 while (n--) {
78 if (n == 0)
79 val = regs->orig_gpr3;
80 else
81 val = regs->gpr[3 + n];
82
83 args[n] = val & mask;
84 }
85}
86
87static inline void syscall_set_arguments(struct task_struct *task,
88 struct pt_regs *regs,
89 const unsigned long *args)
90{
91 memcpy(®s->gpr[3], args, 6 * sizeof(args[0]));
92
93 /* Also copy the first argument into orig_gpr3 */
94 regs->orig_gpr3 = args[0];
95}
96
97static inline int syscall_get_arch(struct task_struct *task)
98{
99 int arch;
100
101 if (IS_ENABLED(CONFIG_PPC64) && !test_tsk_thread_flag(task, TIF_32BIT))
102 arch = AUDIT_ARCH_PPC64;
103 else
104 arch = AUDIT_ARCH_PPC;
105
106#ifdef __LITTLE_ENDIAN__
107 arch |= __AUDIT_ARCH_LE;
108#endif
109 return arch;
110}
111#endif /* _ASM_SYSCALL_H */