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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Access to user system call parameters and results
4 *
5 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
6 *
7 * See asm-generic/syscall.h for descriptions of what we must do here.
8 */
9
10#ifndef _ASM_SYSCALL_H
11#define _ASM_SYSCALL_H 1
12
13#include <uapi/linux/audit.h>
14#include <linux/sched.h>
15#include <linux/thread_info.h>
16
17/* ftrace syscalls requires exporting the sys_call_table */
18extern const unsigned long sys_call_table[];
19extern const unsigned long compat_sys_call_table[];
20
21static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
22{
23 /*
24 * Note that we are returning an int here. That means 0xffffffff, ie.
25 * 32-bit negative 1, will be interpreted as -1 on a 64-bit kernel.
26 * This is important for seccomp so that compat tasks can set r0 = -1
27 * to reject the syscall.
28 */
29 if (trap_is_syscall(regs))
30 return regs->gpr[0];
31 else
32 return -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_error(struct task_struct *task,
42 struct pt_regs *regs)
43{
44 /*
45 * If the system call failed,
46 * regs->gpr[3] contains a positive ERRORCODE.
47 */
48 return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
49}
50
51static inline long syscall_get_return_value(struct task_struct *task,
52 struct pt_regs *regs)
53{
54 return regs->gpr[3];
55}
56
57static inline void syscall_set_return_value(struct task_struct *task,
58 struct pt_regs *regs,
59 int error, long val)
60{
61 /*
62 * In the general case it's not obvious that we must deal with CCR
63 * here, as the syscall exit path will also do that for us. However
64 * there are some places, eg. the signal code, which check ccr to
65 * decide if the value in r3 is actually an error.
66 */
67 if (error) {
68 regs->ccr |= 0x10000000L;
69 regs->gpr[3] = error;
70 } else {
71 regs->ccr &= ~0x10000000L;
72 regs->gpr[3] = val;
73 }
74}
75
76static inline void syscall_get_arguments(struct task_struct *task,
77 struct pt_regs *regs,
78 unsigned long *args)
79{
80 unsigned long val, mask = -1UL;
81 unsigned int n = 6;
82
83#ifdef CONFIG_COMPAT
84 if (test_tsk_thread_flag(task, TIF_32BIT))
85 mask = 0xffffffff;
86#endif
87 while (n--) {
88 if (n == 0)
89 val = regs->orig_gpr3;
90 else
91 val = regs->gpr[3 + n];
92
93 args[n] = val & mask;
94 }
95}
96
97static inline void syscall_set_arguments(struct task_struct *task,
98 struct pt_regs *regs,
99 const unsigned long *args)
100{
101 memcpy(®s->gpr[3], args, 6 * sizeof(args[0]));
102
103 /* Also copy the first argument into orig_gpr3 */
104 regs->orig_gpr3 = args[0];
105}
106
107static inline int syscall_get_arch(struct task_struct *task)
108{
109 int arch;
110
111 if (IS_ENABLED(CONFIG_PPC64) && !test_tsk_thread_flag(task, TIF_32BIT))
112 arch = AUDIT_ARCH_PPC64;
113 else
114 arch = AUDIT_ARCH_PPC;
115
116#ifdef __LITTLE_ENDIAN__
117 arch |= __AUDIT_ARCH_LE;
118#endif
119 return arch;
120}
121#endif /* _ASM_SYSCALL_H */