1 /*
2 * Copyright (c) 2015-2020 François Tigeot <ftigeot@wolfpond.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #ifndef _LINUX_PAGEMAP_H_
28 #define _LINUX_PAGEMAP_H_
29
30 #include <linux/mm.h>
31 #include <linux/fs.h>
32 #include <linux/list.h>
33 #include <linux/highmem.h>
34 #include <linux/compiler.h>
35 #include <asm/uaccess.h>
36 #include <linux/gfp.h>
37 #include <linux/bitops.h>
38 #include <linux/hardirq.h>
39
40 static inline int
fault_in_pages_writeable(char __user * uaddr,int size)41 fault_in_pages_writeable(char __user *uaddr, int size)
42 {
43 int ret = 0;
44 char __user *end = uaddr + size - 1;
45
46 if (unlikely(size == 0))
47 return ret;
48
49 /*
50 * Writing zeroes into userspace here is OK, because we know that if
51 * the zero gets there, we'll be overwriting it.
52 */
53 while (uaddr <= end) {
54 ret = subyte(uaddr, 0);
55 if (ret != 0)
56 return -EFAULT;
57 uaddr += PAGE_SIZE;
58 }
59
60 /* Check whether the range spilled into the next page. */
61 if (((unsigned long)uaddr & ~PAGE_MASK) ==
62 ((unsigned long)end & ~PAGE_MASK))
63 ret = subyte(end, 0);
64
65 return ret;
66 }
67
68 static inline int
fault_in_pages_readable(const char __user * uaddr,int size)69 fault_in_pages_readable(const char __user *uaddr, int size)
70 {
71 char c;
72 int ret = 0;
73 const char __user *end = uaddr + size - 1;
74
75 if (unlikely(size == 0))
76 return ret;
77
78 while (uaddr <= end) {
79 ret = -copyin(uaddr, &c, 1);
80 if (ret != 0)
81 return -EFAULT;
82 uaddr += PAGE_SIZE;
83 }
84
85 /* Check whether the range spilled into the next page. */
86 if (((unsigned long)uaddr & ~PAGE_MASK) ==
87 ((unsigned long)end & ~PAGE_MASK)) {
88 ret = -copyin(end, &c, 1);
89 }
90
91 return ret;
92 }
93
94 static inline gfp_t
mapping_gfp_mask(struct vm_object * mapping)95 mapping_gfp_mask(struct vm_object * mapping)
96 {
97 /* XXX Linux mappings have an associated gfp_mask attribute */
98 return GFP_KERNEL;
99 }
100
101 static inline gfp_t
mapping_gfp_constraint(struct vm_object * mapping,gfp_t gfp_mask)102 mapping_gfp_constraint(struct vm_object *mapping, gfp_t gfp_mask)
103 {
104 return (mapping_gfp_mask(mapping) & gfp_mask);
105 }
106
107 #endif /* _LINUX_PAGEMAP_H_ */
108