linux/arch/csky/lib/usercopy.c
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   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
   7unsigned long raw_copy_from_user(void *to, const void *from,
   8                        unsigned long n)
   9{
  10        int tmp, nsave;
  11
  12        __asm__ __volatile__(
  13        "0:     cmpnei  %1, 0           \n"
  14        "       bf      7f              \n"
  15        "       mov     %3, %1          \n"
  16        "       or      %3, %2          \n"
  17        "       andi    %3, 3           \n"
  18        "       cmpnei  %3, 0           \n"
  19        "       bf      1f              \n"
  20        "       br      5f              \n"
  21        "1:     cmplti  %0, 16          \n"
  22        "       bt      3f              \n"
  23        "2:     ldw     %3, (%2, 0)     \n"
  24        "10:    ldw     %4, (%2, 4)     \n"
  25        "       stw     %3, (%1, 0)     \n"
  26        "       stw     %4, (%1, 4)     \n"
  27        "11:    ldw     %3, (%2, 8)     \n"
  28        "12:    ldw     %4, (%2, 12)    \n"
  29        "       stw     %3, (%1, 8)     \n"
  30        "       stw     %4, (%1, 12)    \n"
  31        "       addi    %2, 16          \n"
  32        "       addi    %1, 16          \n"
  33        "       subi    %0, 16          \n"
  34        "       br      1b              \n"
  35        "3:     cmplti  %0, 4           \n"
  36        "       bt      5f              \n"
  37        "4:     ldw     %3, (%2, 0)     \n"
  38        "       stw     %3, (%1, 0)     \n"
  39        "       addi    %2, 4           \n"
  40        "       addi    %1, 4           \n"
  41        "       subi    %0, 4           \n"
  42        "       br      3b              \n"
  43        "5:     cmpnei  %0, 0           \n"
  44        "       bf      7f              \n"
  45        "6:     ldb     %3, (%2, 0)     \n"
  46        "       stb     %3, (%1, 0)     \n"
  47        "       addi    %2,  1          \n"
  48        "       addi    %1,  1          \n"
  49        "       subi    %0,  1          \n"
  50        "       br      5b              \n"
  51        "8:     stw     %3, (%1, 0)     \n"
  52        "       subi    %0, 4           \n"
  53        "       bf      7f              \n"
  54        "9:     subi    %0, 8           \n"
  55        "       bf      7f              \n"
  56        "13:    stw     %3, (%1, 8)     \n"
  57        "       subi    %0, 12          \n"
  58        "       bf      7f              \n"
  59        ".section __ex_table, \"a\"     \n"
  60        ".align   2                     \n"
  61        ".long    2b, 7f                \n"
  62        ".long    4b, 7f                \n"
  63        ".long    6b, 7f                \n"
  64        ".long   10b, 8b                \n"
  65        ".long   11b, 9b                \n"
  66        ".long   12b,13b                \n"
  67        ".previous                      \n"
  68        "7:                             \n"
  69        : "=r"(n), "=r"(to), "=r"(from), "=r"(nsave),
  70          "=r"(tmp)
  71        : "0"(n), "1"(to), "2"(from)
  72        : "memory");
  73
  74        return n;
  75}
  76EXPORT_SYMBOL(raw_copy_from_user);
  77
  78unsigned long raw_copy_to_user(void *to, const void *from,
  79                        unsigned long n)
  80{
  81        int w0, w1, w2, w3;
  82
  83        __asm__ __volatile__(
  84        "0:     cmpnei  %1, 0           \n"
  85        "       bf      8f              \n"
  86        "       mov     %3, %1          \n"
  87        "       or      %3, %2          \n"
  88        "       andi    %3, 3           \n"
  89        "       cmpnei  %3, 0           \n"
  90        "       bf      1f              \n"
  91        "       br      5f              \n"
  92        "1:     cmplti  %0, 16          \n" /* 4W */
  93        "       bt      3f              \n"
  94        "       ldw     %3, (%2, 0)     \n"
  95        "       ldw     %4, (%2, 4)     \n"
  96        "       ldw     %5, (%2, 8)     \n"
  97        "       ldw     %6, (%2, 12)    \n"
  98        "2:     stw     %3, (%1, 0)     \n"
  99        "9:     stw     %4, (%1, 4)     \n"
 100        "10:    stw     %5, (%1, 8)     \n"
 101        "11:    stw     %6, (%1, 12)    \n"
 102        "       addi    %2, 16          \n"
 103        "       addi    %1, 16          \n"
 104        "       subi    %0, 16          \n"
 105        "       br      1b              \n"
 106        "3:     cmplti  %0, 4           \n" /* 1W */
 107        "       bt      5f              \n"
 108        "       ldw     %3, (%2, 0)     \n"
 109        "4:     stw     %3, (%1, 0)     \n"
 110        "       addi    %2, 4           \n"
 111        "       addi    %1, 4           \n"
 112        "       subi    %0, 4           \n"
 113        "       br      3b              \n"
 114        "5:     cmpnei  %0, 0           \n"  /* 1B */
 115        "       bf      13f             \n"
 116        "       ldb     %3, (%2, 0)     \n"
 117        "6:     stb     %3, (%1, 0)     \n"
 118        "       addi    %2,  1          \n"
 119        "       addi    %1,  1          \n"
 120        "       subi    %0,  1          \n"
 121        "       br      5b              \n"
 122        "7:     subi    %0,  4          \n"
 123        "8:     subi    %0,  4          \n"
 124        "12:    subi    %0,  4          \n"
 125        "       br      13f             \n"
 126        ".section __ex_table, \"a\"     \n"
 127        ".align   2                     \n"
 128        ".long    2b, 13f               \n"
 129        ".long    4b, 13f               \n"
 130        ".long    6b, 13f               \n"
 131        ".long    9b, 12b               \n"
 132        ".long   10b, 8b                \n"
 133        ".long   11b, 7b                \n"
 134        ".previous                      \n"
 135        "13:                            \n"
 136        : "=r"(n), "=r"(to), "=r"(from), "=r"(w0),
 137          "=r"(w1), "=r"(w2), "=r"(w3)
 138        : "0"(n), "1"(to), "2"(from)
 139        : "memory");
 140
 141        return n;
 142}
 143EXPORT_SYMBOL(raw_copy_to_user);
 144
 145/*
 146 * __strncpy_from_user: - Copy a NUL terminated string from userspace,
 147 * with less checking.
 148 * @dst:   Destination address, in kernel space.  This buffer must be at
 149 *         least @count bytes long.
 150 * @src:   Source address, in user space.
 151 * @count: Maximum number of bytes to copy, including the trailing NUL.
 152 *
 153 * Copies a NUL-terminated string from userspace to kernel space.
 154 * Caller must check the specified block with access_ok() before calling
 155 * this function.
 156 *
 157 * On success, returns the length of the string (not including the trailing
 158 * NUL).
 159 *
 160 * If access to userspace fails, returns -EFAULT (some data may have been
 161 * copied).
 162 *
 163 * If @count is smaller than the length of the string, copies @count bytes
 164 * and returns @count.
 165 */
 166long __strncpy_from_user(char *dst, const char *src, long count)
 167{
 168        long res, faultres;
 169        int tmp;
 170
 171        __asm__ __volatile__(
 172        "       cmpnei  %3, 0           \n"
 173        "       bf      4f              \n"
 174        "1:     cmpnei  %1, 0           \n"
 175        "       bf      5f              \n"
 176        "2:     ldb     %4, (%3, 0)     \n"
 177        "       stb     %4, (%2, 0)     \n"
 178        "       cmpnei  %4, 0           \n"
 179        "       bf      3f              \n"
 180        "       addi    %3,  1          \n"
 181        "       addi    %2,  1          \n"
 182        "       subi    %1,  1          \n"
 183        "       br      1b              \n"
 184        "3:     subu    %0, %1          \n"
 185        "       br      5f              \n"
 186        "4:     mov     %0, %5          \n"
 187        "       br      5f              \n"
 188        ".section __ex_table, \"a\"     \n"
 189        ".align   2                     \n"
 190        ".long    2b, 4b                \n"
 191        ".previous                      \n"
 192        "5:                             \n"
 193        : "=r"(res), "=r"(count), "=r"(dst),
 194          "=r"(src), "=r"(tmp), "=r"(faultres)
 195        : "5"(-EFAULT), "0"(count), "1"(count),
 196          "2"(dst), "3"(src)
 197        : "memory");
 198
 199        return res;
 200}
 201EXPORT_SYMBOL(__strncpy_from_user);
 202
 203/*
 204 * strnlen_user: - Get the size of a string in user space.
 205 * @str: The string to measure.
 206 * @n:   The maximum valid length
 207 *
 208 * Get the size of a NUL-terminated string in user space.
 209 *
 210 * Returns the size of the string INCLUDING the terminating NUL.
 211 * On exception, returns 0.
 212 * If the string is too long, returns a value greater than @n.
 213 */
 214long __strnlen_user(const char *s, long n)
 215{
 216        unsigned long res, tmp;
 217
 218        __asm__ __volatile__(
 219        "       cmpnei  %1, 0           \n"
 220        "       bf      3f              \n"
 221        "1:     cmpnei  %0, 0           \n"
 222        "       bf      3f              \n"
 223        "2:     ldb     %3, (%1, 0)     \n"
 224        "       cmpnei  %3, 0           \n"
 225        "       bf      3f              \n"
 226        "       subi    %0,  1          \n"
 227        "       addi    %1,  1          \n"
 228        "       br      1b              \n"
 229        "3:     subu    %2, %0          \n"
 230        "       addi    %2,  1          \n"
 231        "       br      5f              \n"
 232        "4:     movi    %0, 0           \n"
 233        "       br      5f              \n"
 234        ".section __ex_table, \"a\"     \n"
 235        ".align   2                     \n"
 236        ".long    2b, 4b                \n"
 237        ".previous                      \n"
 238        "5:                             \n"
 239        : "=r"(n), "=r"(s), "=r"(res), "=r"(tmp)
 240        : "0"(n), "1"(s), "2"(n)
 241        : "memory");
 242
 243        return res;
 244}
 245EXPORT_SYMBOL(__strnlen_user);
 246
 247/*
 248 * __clear_user: - Zero a block of memory in user space, with less checking.
 249 * @to:   Destination address, in user space.
 250 * @n:    Number of bytes to zero.
 251 *
 252 * Zero a block of memory in user space.  Caller must check
 253 * the specified block with access_ok() before calling this function.
 254 *
 255 * Returns number of bytes that could not be cleared.
 256 * On success, this will be zero.
 257 */
 258unsigned long
 259__clear_user(void __user *to, unsigned long n)
 260{
 261        int data, value, tmp;
 262
 263        __asm__ __volatile__(
 264        "0:     cmpnei  %1, 0           \n"
 265        "       bf      7f              \n"
 266        "       mov     %3, %1          \n"
 267        "       andi    %3, 3           \n"
 268        "       cmpnei  %3, 0           \n"
 269        "       bf      1f              \n"
 270        "       br      5f              \n"
 271        "1:     cmplti  %0, 32          \n" /* 4W */
 272        "       bt      3f              \n"
 273        "8:     stw     %2, (%1, 0)     \n"
 274        "10:    stw     %2, (%1, 4)     \n"
 275        "11:    stw     %2, (%1, 8)     \n"
 276        "12:    stw     %2, (%1, 12)    \n"
 277        "13:    stw     %2, (%1, 16)    \n"
 278        "14:    stw     %2, (%1, 20)    \n"
 279        "15:    stw     %2, (%1, 24)    \n"
 280        "16:    stw     %2, (%1, 28)    \n"
 281        "       addi    %1, 32          \n"
 282        "       subi    %0, 32          \n"
 283        "       br      1b              \n"
 284        "3:     cmplti  %0, 4           \n" /* 1W */
 285        "       bt      5f              \n"
 286        "4:     stw     %2, (%1, 0)     \n"
 287        "       addi    %1, 4           \n"
 288        "       subi    %0, 4           \n"
 289        "       br      3b              \n"
 290        "5:     cmpnei  %0, 0           \n" /* 1B */
 291        "9:     bf      7f              \n"
 292        "6:     stb     %2, (%1, 0)     \n"
 293        "       addi    %1,  1          \n"
 294        "       subi    %0,  1          \n"
 295        "       br      5b              \n"
 296        ".section __ex_table,\"a\"      \n"
 297        ".align   2                     \n"
 298        ".long    8b, 9b                \n"
 299        ".long    10b, 9b               \n"
 300        ".long    11b, 9b               \n"
 301        ".long    12b, 9b               \n"
 302        ".long    13b, 9b               \n"
 303        ".long    14b, 9b               \n"
 304        ".long    15b, 9b               \n"
 305        ".long    16b, 9b               \n"
 306        ".long    4b, 9b                \n"
 307        ".long    6b, 9b                \n"
 308        ".previous                      \n"
 309        "7:                             \n"
 310        : "=r"(n), "=r" (data), "=r"(value), "=r"(tmp)
 311        : "0"(n), "1"(to), "2"(0)
 312        : "memory");
 313
 314        return n;
 315}
 316EXPORT_SYMBOL(__clear_user);
 317