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1/*
2 * User memory access support for Hexagon
3 *
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21#ifndef _ASM_UACCESS_H
22#define _ASM_UACCESS_H
23/*
24 * User space memory access functions
25 */
26#include <linux/mm.h>
27#include <asm/segment.h>
28#include <asm/sections.h>
29
30/*
31 * access_ok: - Checks if a user space pointer is valid
32 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
33 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
34 * to write to a block, it is always safe to read from it.
35 * @addr: User space pointer to start of block to check
36 * @size: Size of block to check
37 *
38 * Context: User context only. This function may sleep if pagefaults are
39 * enabled.
40 *
41 * Checks if a pointer to a block of memory in user space is valid.
42 *
43 * Returns true (nonzero) if the memory block *may* be valid, false (zero)
44 * if it is definitely invalid.
45 *
46 * User address space in Hexagon, like x86, goes to 0xbfffffff, so the
47 * simple MSB-based tests used by MIPS won't work. Some further
48 * optimization is probably possible here, but for now, keep it
49 * reasonably simple and not *too* slow. After all, we've got the
50 * MMU for backup.
51 */
52
53#define __access_ok(addr, size) \
54 ((get_fs().seg == KERNEL_DS.seg) || \
55 (((unsigned long)addr < get_fs().seg) && \
56 (unsigned long)size < (get_fs().seg - (unsigned long)addr)))
57
58/*
59 * When a kernel-mode page fault is taken, the faulting instruction
60 * address is checked against a table of exception_table_entries.
61 * Each entry is a tuple of the address of an instruction that may
62 * be authorized to fault, and the address at which execution should
63 * be resumed instead of the faulting instruction, so as to effect
64 * a workaround.
65 */
66
67/* Assembly somewhat optimized copy routines */
68unsigned long raw_copy_from_user(void *to, const void __user *from,
69 unsigned long n);
70unsigned long raw_copy_to_user(void __user *to, const void *from,
71 unsigned long n);
72#define INLINE_COPY_FROM_USER
73#define INLINE_COPY_TO_USER
74
75__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
76#define __clear_user(a, s) __clear_user_hexagon((a), (s))
77
78#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n)
79
80/* get around the ifndef in asm-generic/uaccess.h */
81#define __strnlen_user __strnlen_user
82
83extern long __strnlen_user(const char __user *src, long n);
84
85static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
86 long n);
87
88#include <asm-generic/uaccess.h>
89
90/* Todo: an actual accelerated version of this. */
91static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
92 long n)
93{
94 long res = __strnlen_user(src, n);
95
96 if (unlikely(!res))
97 return -EFAULT;
98
99 if (res > n) {
100 long left = raw_copy_from_user(dst, src, n);
101 if (unlikely(left))
102 memset(dst + (n - left), 0, left);
103 return n;
104 } else {
105 long left = raw_copy_from_user(dst, src, res);
106 if (unlikely(left))
107 memset(dst + (res - left), 0, left);
108 return res-1;
109 }
110}
111
112#endif
1/*
2 * User memory access support for Hexagon
3 *
4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21#ifndef _ASM_UACCESS_H
22#define _ASM_UACCESS_H
23/*
24 * User space memory access functions
25 */
26#include <linux/sched.h>
27#include <linux/mm.h>
28#include <asm/segment.h>
29#include <asm/sections.h>
30
31/*
32 * access_ok: - Checks if a user space pointer is valid
33 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
34 * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
35 * to write to a block, it is always safe to read from it.
36 * @addr: User space pointer to start of block to check
37 * @size: Size of block to check
38 *
39 * Context: User context only. This function may sleep if pagefaults are
40 * enabled.
41 *
42 * Checks if a pointer to a block of memory in user space is valid.
43 *
44 * Returns true (nonzero) if the memory block *may* be valid, false (zero)
45 * if it is definitely invalid.
46 *
47 * User address space in Hexagon, like x86, goes to 0xbfffffff, so the
48 * simple MSB-based tests used by MIPS won't work. Some further
49 * optimization is probably possible here, but for now, keep it
50 * reasonably simple and not *too* slow. After all, we've got the
51 * MMU for backup.
52 */
53#define VERIFY_READ 0
54#define VERIFY_WRITE 1
55
56#define __access_ok(addr, size) \
57 ((get_fs().seg == KERNEL_DS.seg) || \
58 (((unsigned long)addr < get_fs().seg) && \
59 (unsigned long)size < (get_fs().seg - (unsigned long)addr)))
60
61/*
62 * When a kernel-mode page fault is taken, the faulting instruction
63 * address is checked against a table of exception_table_entries.
64 * Each entry is a tuple of the address of an instruction that may
65 * be authorized to fault, and the address at which execution should
66 * be resumed instead of the faulting instruction, so as to effect
67 * a workaround.
68 */
69
70/* Assembly somewhat optimized copy routines */
71unsigned long __copy_from_user_hexagon(void *to, const void __user *from,
72 unsigned long n);
73unsigned long __copy_to_user_hexagon(void __user *to, const void *from,
74 unsigned long n);
75
76#define __copy_from_user(to, from, n) __copy_from_user_hexagon(to, from, n)
77#define __copy_to_user(to, from, n) __copy_to_user_hexagon(to, from, n)
78
79/*
80 * XXX todo: some additonal performance gain is possible by
81 * implementing __copy_to/from_user_inatomic, which is much
82 * like __copy_to/from_user, but performs slightly less checking.
83 */
84
85__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count);
86#define __clear_user(a, s) __clear_user_hexagon((a), (s))
87
88#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n)
89
90/* get around the ifndef in asm-generic/uaccess.h */
91#define __strnlen_user __strnlen_user
92
93extern long __strnlen_user(const char __user *src, long n);
94
95static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
96 long n);
97
98#include <asm-generic/uaccess.h>
99
100/* Todo: an actual accelerated version of this. */
101static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
102 long n)
103{
104 long res = __strnlen_user(src, n);
105
106 /* return from strnlen can't be zero -- that would be rubbish. */
107
108 if (res > n) {
109 copy_from_user(dst, src, n);
110 return n;
111 } else {
112 copy_from_user(dst, src, res);
113 return res-1;
114 }
115}
116
117#endif