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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 if (trap_is_scv(regs)) {
45 unsigned long error = regs->gpr[3];
46
47 return IS_ERR_VALUE(error) ? error : 0;
48 } else {
49 /*
50 * If the system call failed,
51 * regs->gpr[3] contains a positive ERRORCODE.
52 */
53 return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
54 }
55}
56
57static inline long syscall_get_return_value(struct task_struct *task,
58 struct pt_regs *regs)
59{
60 return regs->gpr[3];
61}
62
63static inline void syscall_set_return_value(struct task_struct *task,
64 struct pt_regs *regs,
65 int error, long val)
66{
67 if (trap_is_scv(regs)) {
68 regs->gpr[3] = (long) error ?: val;
69 } else {
70 /*
71 * In the general case it's not obvious that we must deal with
72 * CCR here, as the syscall exit path will also do that for us.
73 * However there are some places, eg. the signal code, which
74 * check ccr to decide if the value in r3 is actually an error.
75 */
76 if (error) {
77 regs->ccr |= 0x10000000L;
78 regs->gpr[3] = error;
79 } else {
80 regs->ccr &= ~0x10000000L;
81 regs->gpr[3] = val;
82 }
83 }
84}
85
86static inline void syscall_get_arguments(struct task_struct *task,
87 struct pt_regs *regs,
88 unsigned long *args)
89{
90 unsigned long val, mask = -1UL;
91 unsigned int n = 6;
92
93 if (is_tsk_32bit_task(task))
94 mask = 0xffffffff;
95
96 while (n--) {
97 if (n == 0)
98 val = regs->orig_gpr3;
99 else
100 val = regs->gpr[3 + n];
101
102 args[n] = val & mask;
103 }
104}
105
106static inline int syscall_get_arch(struct task_struct *task)
107{
108 if (is_tsk_32bit_task(task))
109 return AUDIT_ARCH_PPC;
110 else if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
111 return AUDIT_ARCH_PPC64LE;
112 else
113 return AUDIT_ARCH_PPC64;
114}
115#endif /* _ASM_SYSCALL_H */