Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * User address space access functions. | |
3 | * | |
4 | * Copyright 1997 Andi Kleen <ak@muc.de> | |
5 | * Copyright 1997 Linus Torvalds | |
6 | * Copyright 2002 Andi Kleen <ak@suse.de> | |
7 | */ | |
2ee60e17 | 8 | #include <linux/module.h> |
1da177e4 LT |
9 | #include <asm/uaccess.h> |
10 | ||
1da177e4 LT |
11 | /* |
12 | * Zero Userspace | |
13 | */ | |
14 | ||
15 | unsigned long __clear_user(void __user *addr, unsigned long size) | |
16 | { | |
17 | long __d0; | |
3ee1afa3 | 18 | might_fault(); |
1da177e4 LT |
19 | /* no memory constraint because it doesn't change any memory gcc knows |
20 | about */ | |
21 | asm volatile( | |
22 | " testq %[size8],%[size8]\n" | |
23 | " jz 4f\n" | |
24 | "0: movq %[zero],(%[dst])\n" | |
25 | " addq %[eight],%[dst]\n" | |
26 | " decl %%ecx ; jnz 0b\n" | |
27 | "4: movq %[size1],%%rcx\n" | |
28 | " testl %%ecx,%%ecx\n" | |
29 | " jz 2f\n" | |
30 | "1: movb %b[zero],(%[dst])\n" | |
31 | " incq %[dst]\n" | |
32 | " decl %%ecx ; jnz 1b\n" | |
33 | "2:\n" | |
34 | ".section .fixup,\"ax\"\n" | |
35 | "3: lea 0(%[size1],%[size8],8),%[size8]\n" | |
36 | " jmp 2b\n" | |
37 | ".previous\n" | |
8da804f2 PA |
38 | _ASM_EXTABLE(0b,3b) |
39 | _ASM_EXTABLE(1b,2b) | |
e0a96129 | 40 | : [size8] "=&c"(size), [dst] "=&D" (__d0) |
1da177e4 LT |
41 | : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr), |
42 | [zero] "r" (0UL), [eight] "r" (8UL)); | |
43 | return size; | |
44 | } | |
2ee60e17 | 45 | EXPORT_SYMBOL(__clear_user); |
1da177e4 LT |
46 | |
47 | unsigned long clear_user(void __user *to, unsigned long n) | |
48 | { | |
49 | if (access_ok(VERIFY_WRITE, to, n)) | |
50 | return __clear_user(to, n); | |
51 | return n; | |
52 | } | |
2ee60e17 | 53 | EXPORT_SYMBOL(clear_user); |
1da177e4 | 54 | |
1da177e4 LT |
55 | unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len) |
56 | { | |
57 | if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { | |
58 | return copy_user_generic((__force void *)to, (__force void *)from, len); | |
59 | } | |
60 | return len; | |
61 | } | |
2ee60e17 AK |
62 | EXPORT_SYMBOL(copy_in_user); |
63 | ||
1129585a VM |
64 | /* |
65 | * Try to copy last bytes and clear the rest if needed. | |
66 | * Since protection fault in copy_from/to_user is not a normal situation, | |
67 | * it is not necessary to optimize tail handling. | |
68 | */ | |
69 | unsigned long | |
70 | copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest) | |
71 | { | |
72 | char c; | |
73 | unsigned zero_len; | |
74 | ||
75 | for (; len; --len) { | |
76 | if (__get_user_nocheck(c, from++, sizeof(char))) | |
77 | break; | |
78 | if (__put_user_nocheck(c, to++, sizeof(char))) | |
79 | break; | |
80 | } | |
81 | ||
82 | for (c = 0, zero_len = len; zerorest && zero_len; --zero_len) | |
83 | if (__put_user_nocheck(c, to++, sizeof(char))) | |
84 | break; | |
85 | return len; | |
86 | } |