1/*	$NetBSD: uaccess.h,v 1.11 2022/10/25 23:38:33 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _ASM_UACCESS_H_
33#define _ASM_UACCESS_H_
34
35#include <sys/types.h>
36#include <sys/errno.h>
37#include <sys/systm.h>
38
39#include <linux/compiler.h>
40
41/* XXX This is a cop-out.  */
42#define	VERIFY_READ	0
43#define	VERIFY_WRITE	1
44static inline bool
45access_ok(const void *uaddr __unused, size_t nbytes __unused)
46{
47	return true;
48}
49
50#define	__copy_from_user	copy_from_user
51#define	__copy_to_user		copy_to_user
52
53static inline int
54copy_from_user(void *kernel_addr, const void *user_addr, size_t len)
55{
56	/* XXX errno NetBSD->Linux */
57	return -copyin(user_addr, kernel_addr, len);
58}
59
60static inline long
61strncpy_from_user(char *kernel_addr, const void *user_addr, long len)
62{
63	size_t done;
64	int error;
65
66	if (len <= 0)
67		return 0;
68	error = copyinstr(user_addr, kernel_addr, len, &done);
69	if (error)
70		return error;
71	KASSERT(done <= (size_t)len);
72	KASSERT(done >= 1);
73	return done - 1;
74}
75
76static inline int
77copy_to_user(void *user_addr, const void *kernel_addr, size_t len)
78{
79	/* XXX errno NetBSD->Linux */
80	return -copyout(kernel_addr, user_addr, len);
81}
82
83#define	get_user(KERNEL_LVAL, USER_PTR)					      \
84	copy_from_user(&(KERNEL_LVAL), (USER_PTR), sizeof(*(USER_PTR)) +      \
85	    0*sizeof(&(KERNEL_LVAL) - (USER_PTR)))
86
87#define	put_user(KERNEL_RVAL, USER_PTR)	({				      \
88	const typeof(*(USER_PTR)) __put_user_tmp = (KERNEL_RVAL);	      \
89	copy_to_user((USER_PTR), &__put_user_tmp, sizeof(__put_user_tmp));    \
90})
91
92#define	__get_user	get_user
93#define	__put_user	put_user
94
95#define	user_access_begin(P,N)	access_ok(P,N)
96#define	user_access_end()	__nothing
97
98#define	unsafe_put_user(KERNEL_RVAL, USER_PTR, LABEL)	do {		      \
99	if (__put_user(KERNEL_RVAL, USER_PTR))				      \
100		goto LABEL;						      \
101} while (0)
102
103static inline size_t
104clear_user(void __user *user_ptr, size_t size)
105{
106	char __user *p = user_ptr;
107	size_t n = size;
108
109	/*
110	 * This loop which sets up a fault handler on every iteration
111	 * is not going to win any speed records, but it'll do to copy
112	 * out an int.
113	 */
114	while (n --> 0) {
115		if (ustore_char(p, 0) != 0)
116			return ++n;
117	}
118
119	return 0;
120}
121
122#if 0
123/*
124 * XXX These `inatomic' versions are a cop out, but they should do for
125 * now -- they are used only in fast paths which can't fault but which
126 * can fall back to slower paths that arrange things so faulting is OK.
127 */
128
129static inline int
130__copy_from_user_inatomic(void *kernel_addr __unused,
131    const void *user_addr __unused, size_t len __unused)
132{
133	return -EFAULT;
134}
135
136static inline int
137__copy_to_user_inatomic(void *user_addr __unused,
138    const void *kernel_addr __unused, size_t len __unused)
139{
140	return -EFAULT;
141}
142#endif	/* 0 */
143
144static inline int
145__copy_from_user_inatomic_nocache(void *kernel_addr __unused,
146    const void *user_addr __unused, size_t len __unused)
147{
148	return -EFAULT;
149}
150
151#endif  /* _ASM_UACCESS_H_ */
152