uaccess.h revision 1.6 
1/*	$NetBSD: uaccess.h,v 1.6 2021/12/19 01:39:41 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/* XXX This is a cop-out.  */
40#define	VERIFY_READ	0
41#define	VERIFY_WRITE	1
42static inline bool
43access_ok(int verify_op __unused, const void *uaddr __unused,
44    size_t nbytes __unused)
45{
46	return true;
47}
48
49#define	__copy_from_user	copy_from_user
50#define	__copy_to_user		copy_to_user
51
52static inline int
53copy_from_user(void *kernel_addr, const void *user_addr, size_t len)
54{
55	/* XXX errno NetBSD->Linux */
56	return -copyin(user_addr, kernel_addr, len);
57}
58
59static inline int
60copy_to_user(void *user_addr, const void *kernel_addr, size_t len)
61{
62	/* XXX errno NetBSD->Linux */
63	return -copyout(kernel_addr, user_addr, len);
64}
65
66#define	get_user(KERNEL_LVAL, USER_PTR)					      \
67	copy_from_user(&(KERNEL_LVAL), (USER_PTR), sizeof(*(USER_PTR)) +      \
68	    0*sizeof(&(KERNEL_LVAL) - (USER_PTR)))
69
70#define	put_user(KERNEL_RVAL, USER_PTR)	({				      \
71	const typeof(*(USER_PTR)) __put_user_tmp = (KERNEL_RVAL);	      \
72	copy_to_user((USER_PTR), &__put_user_tmp, sizeof(__put_user_tmp));    \
73})
74
75#define	__get_user	get_user
76#define	__put_user	put_user
77
78#define	user_access_begin()	__nothing
79#define	user_access_end()	__nothing
80
81#define	unsafe_put_user(KERNEL_RVAL, USER_PTR, LABEL)	do {		      \
82	if (__put_user(KERNEL_RVAL, USER_PTR))				      \
83		goto LABEL;						      \
84} while (0)
85
86static inline size_t
87clear_user(void __user *user_ptr, size_t size)
88{
89	char __user *p = user_ptr;
90	size_t n = size;
91
92	/*
93	 * This loop which sets up a fault handler on every iteration
94	 * is not going to win any speed records, but it'll do to copy
95	 * out an int.
96	 */
97	while (n --> 0) {
98		if (subyte(p, 0) != 0)
99			return ++n;
100	}
101
102	return 0;
103}
104
105#if 0
106/*
107 * XXX These `inatomic' versions are a cop out, but they should do for
108 * now -- they are used only in fast paths which can't fault but which
109 * can fall back to slower paths that arrange things so faulting is OK.
110 */
111
112static inline int
113__copy_from_user_inatomic(void *kernel_addr __unused,
114    const void *user_addr __unused, size_t len __unused)
115{
116	return -EFAULT;
117}
118
119static inline int
120__copy_to_user_inatomic(void *user_addr __unused,
121    const void *kernel_addr __unused, size_t len __unused)
122{
123	return -EFAULT;
124}
125#endif	/* 0 */
126
127static inline int
128__copy_from_user_inatomic_nocache(void *kernel_addr __unused,
129    const void *user_addr __unused, size_t len __unused)
130{
131	return -EFAULT;
132}
133
134#endif  /* _ASM_UACCESS_H_ */
135