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