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1 | /* |
2 | * User memory access support for Hexagon | |
3 | * | |
e1858b2a | 4 | * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
7567746e RK |
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 | * | |
b3c395ef DH |
39 | * Context: User context only. This function may sleep if pagefaults are |
40 | * enabled. | |
7567746e RK |
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 */ | |
71 | unsigned long __copy_from_user_hexagon(void *to, const void __user *from, | |
72 | unsigned long n); | |
73 | unsigned 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 | ||
93 | extern long __strnlen_user(const char __user *src, long n); | |
94 | ||
95 | static 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. */ | |
101 | static 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 |