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