arch/score/include/asm/uaccess.h

   1 #ifndef __SCORE_UACCESS_H
   2 #define __SCORE_UACCESS_H
   3
   4 #include <linux/kernel.h>
   5 #include <linux/errno.h>
   6 #include <linux/thread_info.h>
   7 #include <asm/extable.h>
   8
   9 #define VERIFY_READ             0
  10 #define VERIFY_WRITE            1
  11
  12 #define get_ds()                (KERNEL_DS)
  13 #define get_fs()                (current_thread_info()->addr_limit)
  14 #define segment_eq(a, b)        ((a).seg == (b).seg)
  15
  16 /*
  17  * Is a address valid? This does a straighforward calculation rather
  18  * than tests.
  19  *
  20  * Address valid if:
  21  *  - "addr" doesn't have any high-bits set
  22  *  - AND "size" doesn't have any high-bits set
  23  *  - AND "addr+size" doesn't have any high-bits set
  24  *  - OR we are in kernel mode.
  25  *
  26  * __ua_size() is a trick to avoid runtime checking of positive constant
  27  * sizes; for those we already know at compile time that the size is ok.
  28  */
  29 #define __ua_size(size)                                                 \
  30         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  31
  32 /*
  33  * access_ok: - Checks if a user space pointer is valid
  34  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  35  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  36  *        to write to a block, it is always safe to read from it.
  37  * @addr: User space pointer to start of block to check
  38  * @size: Size of block to check
  39  *
  40  * Context: User context only. This function may sleep if pagefaults are
  41  *          enabled.
  42  *
  43  * Checks if a pointer to a block of memory in user space is valid.
  44  *
  45  * Returns true (nonzero) if the memory block may be valid, false (zero)
  46  * if it is definitely invalid.
  47  *
  48  * Note that, depending on architecture, this function probably just
  49  * checks that the pointer is in the user space range - after calling
  50  * this function, memory access functions may still return -EFAULT.
  51  */
  52
  53 #define __access_ok(addr, size)                                 \
  54         (((long)((get_fs().seg) &                               \
  55                  ((addr) | ((addr) + (size)) |                  \
  56                   __ua_size(size)))) == 0)
  57
  58 #define access_ok(type, addr, size)                             \
  59         likely(__access_ok((unsigned long)(addr), (size)))
  60
  61 /*
  62  * put_user: - Write a simple value into user space.
  63  * @x:   Value to copy to user space.
  64  * @ptr: Destination address, in user space.
  65  *
  66  * Context: User context only. This function may sleep if pagefaults are
  67  *          enabled.
  68  *
  69  * This macro copies a single simple value from kernel space to user
  70  * space.  It supports simple types like char and int, but not larger
  71  * data types like structures or arrays.
  72  *
  73  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
  74  * to the result of dereferencing @ptr.
  75  *
  76  * Returns zero on success, or -EFAULT on error.
  77  */
  78 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
  79
  80 /*
  81  * get_user: - Get a simple variable from user space.
  82  * @x:   Variable to store result.
  83  * @ptr: Source address, in user space.
  84  *
  85  * Context: User context only. This function may sleep if pagefaults are
  86  *          enabled.
  87  *
  88  * This macro copies a single simple variable from user space to kernel
  89  * space.  It supports simple types like char and int, but not larger
  90  * data types like structures or arrays.
  91  *
  92  * @ptr must have pointer-to-simple-variable type, and the result of
  93  * dereferencing @ptr must be assignable to @x without a cast.
  94  *
  95  * Returns zero on success, or -EFAULT on error.
  96  * On error, the variable @x is set to zero.
  97  */
  98 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
  99
 100 /*
 101  * __put_user: - Write a simple value into user space, with less checking.
 102  * @x:   Value to copy to user space.
 103  * @ptr: Destination address, in user space.
 104  *
 105  * Context: User context only. This function may sleep if pagefaults are
 106  *          enabled.
 107  *
 108  * This macro copies a single simple value from kernel space to user
 109  * space.  It supports simple types like char and int, but not larger
 110  * data types like structures or arrays.
 111  *
 112  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 113  * to the result of dereferencing @ptr.
 114  *
 115  * Caller must check the pointer with access_ok() before calling this
 116  * function.
 117  *
 118  * Returns zero on success, or -EFAULT on error.
 119  */
 120 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 121
 122 /*
 123  * __get_user: - Get a simple variable from user space, with less checking.
 124  * @x:   Variable to store result.
 125  * @ptr: Source address, in user space.
 126  *
 127  * Context: User context only. This function may sleep if pagefaults are
 128  *          enabled.
 129  *
 130  * This macro copies a single simple variable from user space to kernel
 131  * space.  It supports simple types like char and int, but not larger
 132  * data types like structures or arrays.
 133  *
 134  * @ptr must have pointer-to-simple-variable type, and the result of
 135  * dereferencing @ptr must be assignable to @x without a cast.
 136  *
 137  * Caller must check the pointer with access_ok() before calling this
 138  * function.
 139  *
 140  * Returns zero on success, or -EFAULT on error.
 141  * On error, the variable @x is set to zero.
 142  */
 143 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 144
 145 struct __large_struct { unsigned long buf[100]; };
 146 #define __m(x) (*(struct __large_struct __user *)(x))
 147
 148 /*
 149  * Yuck.  We need two variants, one for 64bit operation and one
 150  * for 32 bit mode and old iron.
 151  */
 152 extern void __get_user_unknown(void);
 153
 154 #define __get_user_common(val, size, ptr)                               \
 155 do {                                                                    \
 156         switch (size) {                                                 \
 157         case 1:                                                         \
 158                 __get_user_asm(val, "lb", ptr);                         \
 159                 break;                                                  \
 160         case 2:                                                         \
 161                 __get_user_asm(val, "lh", ptr);                         \
 162                  break;                                                 \
 163         case 4:                                                         \
 164                 __get_user_asm(val, "lw", ptr);                         \
 165                  break;                                                 \
 166         case 8:                                                         \
 167                 if (__copy_from_user((void *)&val, ptr, 8) == 0)        \
 168                         __gu_err = 0;                                   \
 169                 else                                                    \
 170                         __gu_err = -EFAULT;                             \
 171                 break;                                                  \
 172         default:                                                        \
 173                 __get_user_unknown();                                   \
 174                 break;                                                  \
 175         }                                                               \
 176 } while (0)
 177
 178 #define __get_user_nocheck(x, ptr, size)                                \
 179 ({                                                                      \
 180         long __gu_err = 0;                                              \
 181         __get_user_common((x), size, ptr);                              \
 182         __gu_err;                                                       \
 183 })
 184
 185 #define __get_user_check(x, ptr, size)                                  \
 186 ({                                                                      \
 187         long __gu_err = -EFAULT;                                        \
 188         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
 189                                                                         \
 190         if (likely(access_ok(VERIFY_READ, __gu_ptr, size)))             \
 191                 __get_user_common((x), size, __gu_ptr);                 \
 192         else                                                            \
 193                 (x) = 0;                                                \
 194                                                                         \
 195         __gu_err;                                                       \
 196 })
 197
 198 #define __get_user_asm(val, insn, addr)                                 \
 199 {                                                                       \
 200         long __gu_tmp;                                                  \
 201                                                                         \
 202         __asm__ __volatile__(                                           \
 203                 "1:" insn " %1, %3\n"                                   \
 204                 "2:\n"                                                  \
 205                 ".section .fixup,\"ax\"\n"                              \
 206                 "3:li   %0, %4\n"                                       \
 207                 "li     %1, 0\n"                                        \
 208                 "j      2b\n"                                           \
 209                 ".previous\n"                                           \
 210                 ".section __ex_table,\"a\"\n"                           \
 211                 ".word  1b, 3b\n"                                       \
 212                 ".previous\n"                                           \
 213                 : "=r" (__gu_err), "=r" (__gu_tmp)                      \
 214                 : "0" (0), "o" (__m(addr)), "i" (-EFAULT));             \
 215                                                                         \
 216                 (val) = (__typeof__(*(addr))) __gu_tmp;                 \
 217 }
 218
 219 /*
 220  * Yuck.  We need two variants, one for 64bit operation and one
 221  * for 32 bit mode and old iron.
 222  */
 223 #define __put_user_nocheck(val, ptr, size)                              \
 224 ({                                                                      \
 225         __typeof__(*(ptr)) __pu_val;                                    \
 226         long __pu_err = 0;                                              \
 227                                                                         \
 228         __pu_val = (val);                                               \
 229         switch (size) {                                                 \
 230         case 1:                                                         \
 231                 __put_user_asm("sb", ptr);                              \
 232                 break;                                                  \
 233         case 2:                                                         \
 234                 __put_user_asm("sh", ptr);                              \
 235                 break;                                                  \
 236         case 4:                                                         \
 237                 __put_user_asm("sw", ptr);                              \
 238                 break;                                                  \
 239         case 8:                                                         \
 240                 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0)   \
 241                         __pu_err = 0;                                   \
 242                 else                                                    \
 243                         __pu_err = -EFAULT;                             \
 244                 break;                                                  \
 245         default:                                                        \
 246                  __put_user_unknown();                                  \
 247                  break;                                                 \
 248         }                                                               \
 249         __pu_err;                                                       \
 250 })
 251
 252
 253 #define __put_user_check(val, ptr, size)                                \
 254 ({                                                                      \
 255         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 256         __typeof__(*(ptr)) __pu_val = (val);                            \
 257         long __pu_err = -EFAULT;                                        \
 258                                                                         \
 259         if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) {         \
 260                 switch (size) {                                         \
 261                 case 1:                                                 \
 262                         __put_user_asm("sb", __pu_addr);                \
 263                         break;                                          \
 264                 case 2:                                                 \
 265                         __put_user_asm("sh", __pu_addr);                \
 266                         break;                                          \
 267                 case 4:                                                 \
 268                         __put_user_asm("sw", __pu_addr);                \
 269                         break;                                          \
 270                 case 8:                                                 \
 271                         if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
 272                                 __pu_err = 0;                           \
 273                         else                                            \
 274                                 __pu_err = -EFAULT;                     \
 275                         break;                                          \
 276                 default:                                                \
 277                         __put_user_unknown();                           \
 278                         break;                                          \
 279                 }                                                       \
 280         }                                                               \
 281         __pu_err;                                                       \
 282 })
 283
 284 #define __put_user_asm(insn, ptr)                                       \
 285         __asm__ __volatile__(                                           \
 286                 "1:" insn " %2, %3\n"                                   \
 287                 "2:\n"                                                  \
 288                 ".section .fixup,\"ax\"\n"                              \
 289                 "3:li %0, %4\n"                                         \
 290                 "j 2b\n"                                                \
 291                 ".previous\n"                                           \
 292                 ".section __ex_table,\"a\"\n"                           \
 293                 ".word 1b, 3b\n"                                        \
 294                 ".previous\n"                                           \
 295                 : "=r" (__pu_err)                                       \
 296                 : "0" (0), "r" (__pu_val), "o" (__m(ptr)),              \
 297                   "i" (-EFAULT));
 298
 299 extern void __put_user_unknown(void);
 300 extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
 301
 302 static inline unsigned long
 303 copy_from_user(void *to, const void *from, unsigned long len)
 304 {
 305         unsigned long res = len;
 306
 307         if (likely(access_ok(VERIFY_READ, from, len)))
 308                 res = __copy_tofrom_user(to, from, len);
 309
 310         if (unlikely(res))
 311                 memset(to + (len - res), 0, res);
 312
 313         return res;
 314 }
 315
 316 static inline unsigned long
 317 copy_to_user(void *to, const void *from, unsigned long len)
 318 {
 319         if (likely(access_ok(VERIFY_WRITE, to, len)))
 320                 len = __copy_tofrom_user(to, from, len);
 321
 322         return len;
 323 }
 324
 325 static inline unsigned long
 326 __copy_from_user(void *to, const void *from, unsigned long len)
 327 {
 328         unsigned long left = __copy_tofrom_user(to, from, len);
 329         if (unlikely(left))
 330                 memset(to + (len - left), 0, left);
 331         return left;
 332 }
 333
 334 #define __copy_to_user(to, from, len)           \
 335                 __copy_tofrom_user((to), (from), (len))
 336
 337 static inline unsigned long
 338 __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
 339 {
 340         return __copy_to_user(to, from, len);
 341 }
 342
 343 static inline unsigned long
 344 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
 345 {
 346         return __copy_tofrom_user(to, from, len);
 347 }
 348
 349 #define __copy_in_user(to, from, len)   __copy_tofrom_user(to, from, len)
 350
 351 static inline unsigned long
 352 copy_in_user(void *to, const void *from, unsigned long len)
 353 {
 354         if (access_ok(VERIFY_READ, from, len) &&
 355                       access_ok(VERFITY_WRITE, to, len))
 356                 return __copy_tofrom_user(to, from, len);
 357 }
 358
 359 /*
 360  * __clear_user: - Zero a block of memory in user space, with less checking.
 361  * @to:   Destination address, in user space.
 362  * @n:    Number of bytes to zero.
 363  *
 364  * Zero a block of memory in user space.  Caller must check
 365  * the specified block with access_ok() before calling this function.
 366  *
 367  * Returns number of bytes that could not be cleared.
 368  * On success, this will be zero.
 369  */
 370 extern unsigned long __clear_user(void __user *src, unsigned long size);
 371
 372 static inline unsigned long clear_user(char *src, unsigned long size)
 373 {
 374         if (access_ok(VERIFY_WRITE, src, size))
 375                 return __clear_user(src, size);
 376
 377         return -EFAULT;
 378 }
 379 /*
 380  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 381  * @dst:   Destination address, in kernel space.  This buffer must be at
 382  *         least @count bytes long.
 383  * @src:   Source address, in user space.
 384  * @count: Maximum number of bytes to copy, including the trailing NUL.
 385  *
 386  * Copies a NUL-terminated string from userspace to kernel space.
 387  * Caller must check the specified block with access_ok() before calling
 388  * this function.
 389  *
 390  * On success, returns the length of the string (not including the trailing
 391  * NUL).
 392  *
 393  * If access to userspace fails, returns -EFAULT (some data may have been
 394  * copied).
 395  *
 396  * If @count is smaller than the length of the string, copies @count bytes
 397  * and returns @count.
 398  */
 399 extern int __strncpy_from_user(char *dst, const char *src, long len);
 400
 401 static inline int strncpy_from_user(char *dst, const char *src, long len)
 402 {
 403         if (access_ok(VERIFY_READ, src, 1))
 404                 return __strncpy_from_user(dst, src, len);
 405
 406         return -EFAULT;
 407 }
 408
 409 extern int __strlen_user(const char *src);
 410 static inline long strlen_user(const char __user *src)
 411 {
 412         return __strlen_user(src);
 413 }
 414
 415 extern int __strnlen_user(const char *str, long len);
 416 static inline long strnlen_user(const char __user *str, long len)
 417 {
 418         if (!access_ok(VERIFY_READ, str, 0))
 419                 return 0;
 420         else
 421                 return __strnlen_user(str, len);
 422 }
 423
 424 #endif /* __SCORE_UACCESS_H */
 425