[PATCH] m68k: kill mach_floppy_setup, convert to proper __setup() in drivers
[linux-2.6.git] / arch / x86_64 / lib / usercopy.c
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  */
8 #include <asm/uaccess.h>
9
10 /*
11  * Copy a null terminated string from userspace.
12  */
13
14 #define __do_strncpy_from_user(dst,src,count,res)                          \
15 do {                                                                       \
16         long __d0, __d1, __d2;                                             \
17         might_sleep();                                                     \
18         __asm__ __volatile__(                                              \
19                 "       testq %1,%1\n"                                     \
20                 "       jz 2f\n"                                           \
21                 "0:     lodsb\n"                                           \
22                 "       stosb\n"                                           \
23                 "       testb %%al,%%al\n"                                 \
24                 "       jz 1f\n"                                           \
25                 "       decq %1\n"                                         \
26                 "       jnz 0b\n"                                          \
27                 "1:     subq %1,%0\n"                                      \
28                 "2:\n"                                                     \
29                 ".section .fixup,\"ax\"\n"                                 \
30                 "3:     movq %5,%0\n"                                      \
31                 "       jmp 2b\n"                                          \
32                 ".previous\n"                                              \
33                 ".section __ex_table,\"a\"\n"                              \
34                 "       .align 8\n"                                        \
35                 "       .quad 0b,3b\n"                                     \
36                 ".previous"                                                \
37                 : "=r"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1),      \
38                   "=&D" (__d2)                                             \
39                 : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
40                 : "memory");                                               \
41 } while (0)
42
43 long
44 __strncpy_from_user(char *dst, const char __user *src, long count)
45 {
46         long res;
47         __do_strncpy_from_user(dst, src, count, res);
48         return res;
49 }
50
51 long
52 strncpy_from_user(char *dst, const char __user *src, long count)
53 {
54         long res = -EFAULT;
55         if (access_ok(VERIFY_READ, src, 1))
56                 __do_strncpy_from_user(dst, src, count, res);
57         return res;
58 }
59
60 /*
61  * Zero Userspace
62  */
63
64 unsigned long __clear_user(void __user *addr, unsigned long size)
65 {
66         long __d0;
67         might_sleep();
68         /* no memory constraint because it doesn't change any memory gcc knows
69            about */
70         asm volatile(
71                 "       testq  %[size8],%[size8]\n"
72                 "       jz     4f\n"
73                 "0:     movq %[zero],(%[dst])\n"
74                 "       addq   %[eight],%[dst]\n"
75                 "       decl %%ecx ; jnz   0b\n"
76                 "4:     movq  %[size1],%%rcx\n"
77                 "       testl %%ecx,%%ecx\n"
78                 "       jz     2f\n"
79                 "1:     movb   %b[zero],(%[dst])\n"
80                 "       incq   %[dst]\n"
81                 "       decl %%ecx ; jnz  1b\n"
82                 "2:\n"
83                 ".section .fixup,\"ax\"\n"
84                 "3:     lea 0(%[size1],%[size8],8),%[size8]\n"
85                 "       jmp 2b\n"
86                 ".previous\n"
87                 ".section __ex_table,\"a\"\n"
88                 "       .align 8\n"
89                 "       .quad 0b,3b\n"
90                 "       .quad 1b,2b\n"
91                 ".previous"
92                 : [size8] "=c"(size), [dst] "=&D" (__d0)
93                 : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
94                   [zero] "r" (0UL), [eight] "r" (8UL));
95         return size;
96 }
97
98
99 unsigned long clear_user(void __user *to, unsigned long n)
100 {
101         if (access_ok(VERIFY_WRITE, to, n))
102                 return __clear_user(to, n);
103         return n;
104 }
105
106 /*
107  * Return the size of a string (including the ending 0)
108  *
109  * Return 0 on exception, a value greater than N if too long
110  */
111
112 long __strnlen_user(const char __user *s, long n)
113 {
114         long res = 0;
115         char c;
116
117         while (1) {
118                 if (res>n)
119                         return n+1;
120                 if (__get_user(c, s))
121                         return 0;
122                 if (!c)
123                         return res+1;
124                 res++;
125                 s++;
126         }
127 }
128
129 long strnlen_user(const char __user *s, long n)
130 {
131         if (!access_ok(VERIFY_READ, s, n))
132                 return 0;
133         return __strnlen_user(s, n);
134 }
135
136 long strlen_user(const char __user *s)
137 {
138         long res = 0;
139         char c;
140
141         for (;;) {
142                 if (get_user(c, s))
143                         return 0;
144                 if (!c)
145                         return res+1;
146                 res++;
147                 s++;
148         }
149 }
150
151 unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
152 {
153         if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { 
154                 return copy_user_generic((__force void *)to, (__force void *)from, len);
155         } 
156         return len;             
157 }