arch/csky/lib/usercopy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/uaccess.h>
   5 #include <linux/types.h>
   6
   7 unsigned long raw_copy_from_user(void *to, const void *from,
   8                         unsigned long n)
   9 {
  10         if (access_ok(VERIFY_READ, from, n))
  11                 __copy_user_zeroing(to, from, n);
  12         else
  13                 memset(to, 0, n);
  14         return n;
  15 }
  16 EXPORT_SYMBOL(raw_copy_from_user);
  17
  18 unsigned long raw_copy_to_user(void *to, const void *from,
  19                         unsigned long n)
  20 {
  21         if (access_ok(VERIFY_WRITE, to, n))
  22                 __copy_user(to, from, n);
  23         return n;
  24 }
  25 EXPORT_SYMBOL(raw_copy_to_user);
  26
  27
  28 /*
  29  * copy a null terminated string from userspace.
  30  */
  31 #define __do_strncpy_from_user(dst, src, count, res)    \
  32 do {                                                    \
  33         int tmp;                                        \
  34         long faultres;                                  \
  35         asm volatile(                                   \
  36         "       cmpnei  %3, 0           \n"             \
  37         "       bf      4f              \n"             \
  38         "1:     cmpnei  %1, 0           \n"             \
  39         "       bf      5f              \n"             \
  40         "2:     ldb     %4, (%3, 0)     \n"             \
  41         "       stb     %4, (%2, 0)     \n"             \
  42         "       cmpnei  %4, 0           \n"             \
  43         "       bf      3f              \n"             \
  44         "       addi    %3,  1          \n"             \
  45         "       addi    %2,  1          \n"             \
  46         "       subi    %1,  1          \n"             \
  47         "       br      1b              \n"             \
  48         "3:     subu    %0, %1          \n"             \
  49         "       br      5f              \n"             \
  50         "4:     mov     %0, %5          \n"             \
  51         "       br      5f              \n"             \
  52         ".section __ex_table, \"a\"     \n"             \
  53         ".align   2                     \n"             \
  54         ".long    2b, 4b                \n"             \
  55         ".previous                      \n"             \
  56         "5:                             \n"             \
  57         : "=r"(res), "=r"(count), "=r"(dst),            \
  58           "=r"(src), "=r"(tmp),   "=r"(faultres)        \
  59         : "5"(-EFAULT), "0"(count), "1"(count),         \
  60           "2"(dst), "3"(src)                            \
  61         : "memory", "cc");                              \
  62 } while (0)
  63
  64 /*
  65  * __strncpy_from_user: - Copy a NUL terminated string from userspace,
  66  * with less checking.
  67  * @dst:   Destination address, in kernel space.  This buffer must be at
  68  *         least @count bytes long.
  69  * @src:   Source address, in user space.
  70  * @count: Maximum number of bytes to copy, including the trailing NUL.
  71  *
  72  * Copies a NUL-terminated string from userspace to kernel space.
  73  * Caller must check the specified block with access_ok() before calling
  74  * this function.
  75  *
  76  * On success, returns the length of the string (not including the trailing
  77  * NUL).
  78  *
  79  * If access to userspace fails, returns -EFAULT (some data may have been
  80  * copied).
  81  *
  82  * If @count is smaller than the length of the string, copies @count bytes
  83  * and returns @count.
  84  */
  85 long __strncpy_from_user(char *dst, const char *src, long count)
  86 {
  87         long res;
  88
  89         __do_strncpy_from_user(dst, src, count, res);
  90         return res;
  91 }
  92 EXPORT_SYMBOL(__strncpy_from_user);
  93
  94 /*
  95  * strncpy_from_user: - Copy a NUL terminated string from userspace.
  96  * @dst:   Destination address, in kernel space.  This buffer must be at
  97  *         least @count bytes long.
  98  * @src:   Source address, in user space.
  99  * @count: Maximum number of bytes to copy, including the trailing NUL.
 100  *
 101  * Copies a NUL-terminated string from userspace to kernel space.
 102  *
 103  * On success, returns the length of the string (not including the trailing
 104  * NUL).
 105  *
 106  * If access to userspace fails, returns -EFAULT (some data may have been
 107  * copied).
 108  *
 109  * If @count is smaller than the length of the string, copies @count bytes
 110  * and returns @count.
 111  */
 112 long strncpy_from_user(char *dst, const char *src, long count)
 113 {
 114         long res = -EFAULT;
 115
 116         if (access_ok(VERIFY_READ, src, 1))
 117                 __do_strncpy_from_user(dst, src, count, res);
 118         return res;
 119 }
 120 EXPORT_SYMBOL(strncpy_from_user);
 121
 122 /*
 123  * strlen_user: - Get the size of a string in user space.
 124  * @str: The string to measure.
 125  * @n:   The maximum valid length
 126  *
 127  * Get the size of a NUL-terminated string in user space.
 128  *
 129  * Returns the size of the string INCLUDING the terminating NUL.
 130  * On exception, returns 0.
 131  * If the string is too long, returns a value greater than @n.
 132  */
 133 long strnlen_user(const char *s, long n)
 134 {
 135         unsigned long res, tmp;
 136
 137         if (s == NULL)
 138                 return 0;
 139
 140         asm volatile(
 141         "       cmpnei  %1, 0           \n"
 142         "       bf      3f              \n"
 143         "1:     cmpnei  %0, 0           \n"
 144         "       bf      3f              \n"
 145         "2:     ldb     %3, (%1, 0)     \n"
 146         "       cmpnei  %3, 0           \n"
 147         "       bf      3f              \n"
 148         "       subi    %0,  1          \n"
 149         "       addi    %1,  1          \n"
 150         "       br      1b              \n"
 151         "3:     subu    %2, %0          \n"
 152         "       addi    %2,  1          \n"
 153         "       br      5f              \n"
 154         "4:     movi    %0, 0           \n"
 155         "       br      5f              \n"
 156         ".section __ex_table, \"a\"     \n"
 157         ".align   2                     \n"
 158         ".long    2b, 4b                \n"
 159         ".previous                      \n"
 160         "5:                             \n"
 161         : "=r"(n), "=r"(s), "=r"(res), "=r"(tmp)
 162         : "0"(n), "1"(s), "2"(n)
 163         : "memory", "cc");
 164
 165         return res;
 166 }
 167 EXPORT_SYMBOL(strnlen_user);
 168
 169 #define __do_clear_user(addr, size)                     \
 170 do {                                                    \
 171         int __d0, zvalue, tmp;                          \
 172                                                         \
 173         asm volatile(                                   \
 174         "0:     cmpnei  %1, 0           \n"             \
 175         "       bf      7f              \n"             \
 176         "       mov     %3, %1          \n"             \
 177         "       andi    %3, 3           \n"             \
 178         "       cmpnei  %3, 0           \n"             \
 179         "       bf      1f              \n"             \
 180         "       br      5f              \n"             \
 181         "1:     cmplti  %0, 32          \n" /* 4W */    \
 182         "       bt      3f              \n"             \
 183         "8:     stw     %2, (%1, 0)     \n"             \
 184         "10:    stw     %2, (%1, 4)     \n"             \
 185         "11:    stw     %2, (%1, 8)     \n"             \
 186         "12:    stw     %2, (%1, 12)    \n"             \
 187         "13:    stw     %2, (%1, 16)    \n"             \
 188         "14:    stw     %2, (%1, 20)    \n"             \
 189         "15:    stw     %2, (%1, 24)    \n"             \
 190         "16:    stw     %2, (%1, 28)    \n"             \
 191         "       addi    %1, 32          \n"             \
 192         "       subi    %0, 32          \n"             \
 193         "       br      1b              \n"             \
 194         "3:     cmplti  %0, 4           \n" /* 1W */    \
 195         "       bt      5f              \n"             \
 196         "4:     stw     %2, (%1, 0)     \n"             \
 197         "       addi    %1, 4           \n"             \
 198         "       subi    %0, 4           \n"             \
 199         "       br      3b              \n"             \
 200         "5:     cmpnei  %0, 0           \n" /* 1B */    \
 201         "9:     bf      7f              \n"             \
 202         "6:     stb     %2, (%1, 0)     \n"             \
 203         "       addi    %1,  1          \n"             \
 204         "       subi    %0,  1          \n"             \
 205         "       br      5b              \n"             \
 206         ".section __ex_table,\"a\"      \n"             \
 207         ".align   2                     \n"             \
 208         ".long    8b, 9b                \n"             \
 209         ".long    10b, 9b               \n"             \
 210         ".long    11b, 9b               \n"             \
 211         ".long    12b, 9b               \n"             \
 212         ".long    13b, 9b               \n"             \
 213         ".long    14b, 9b               \n"             \
 214         ".long    15b, 9b               \n"             \
 215         ".long    16b, 9b               \n"             \
 216         ".long    4b, 9b                \n"             \
 217         ".long    6b, 9b                \n"             \
 218         ".previous                      \n"             \
 219         "7:                             \n"             \
 220         : "=r"(size), "=r" (__d0),                      \
 221           "=r"(zvalue), "=r"(tmp)                       \
 222         : "0"(size), "1"(addr), "2"(0)                  \
 223         : "memory", "cc");                              \
 224 } while (0)
 225
 226 /*
 227  * clear_user: - Zero a block of memory in user space.
 228  * @to:   Destination address, in user space.
 229  * @n:    Number of bytes to zero.
 230  *
 231  * Zero a block of memory in user space.
 232  *
 233  * Returns number of bytes that could not be cleared.
 234  * On success, this will be zero.
 235  */
 236 unsigned long
 237 clear_user(void __user *to, unsigned long n)
 238 {
 239         if (access_ok(VERIFY_WRITE, to, n))
 240                 __do_clear_user(to, n);
 241         return n;
 242 }
 243 EXPORT_SYMBOL(clear_user);
 244
 245 /*
 246  * __clear_user: - Zero a block of memory in user space, with less checking.
 247  * @to:   Destination address, in user space.
 248  * @n:    Number of bytes to zero.
 249  *
 250  * Zero a block of memory in user space.  Caller must check
 251  * the specified block with access_ok() before calling this function.
 252  *
 253  * Returns number of bytes that could not be cleared.
 254  * On success, this will be zero.
 255  */
 256 unsigned long
 257 __clear_user(void __user *to, unsigned long n)
 258 {
 259         __do_clear_user(to, n);
 260         return n;
 261 }
 262 EXPORT_SYMBOL(__clear_user);