kernel/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 if pagefaults are
  40  *          enabled.
  41  *
  42  * Checks if a pointer to a block of memory in user space is valid.
  43  *
  44  * Returns true (nonzero) if the memory block may be valid, false (zero)
  45  * if it is definitely invalid.
  46  *
  47  * Note that, depending on architecture, this function probably just
  48  * checks that the pointer is in the user space range - after calling
  49  * this function, memory access functions may still return -EFAULT.
  50  */
  51
  52 #define __access_ok(addr, size)                                 \
  53         (((long)((get_fs().seg) &                               \
  54                  ((addr) | ((addr) + (size)) |                  \
  55                   __ua_size(size)))) == 0)
  56
  57 #define access_ok(type, addr, size)                             \
  58         likely(__access_ok((unsigned long)(addr), (size)))
  59
  60 /*
  61  * put_user: - Write a simple value into user space.
  62  * @x:   Value to copy to user space.
  63  * @ptr: Destination address, in user space.
  64  *
  65  * Context: User context only. This function may sleep if pagefaults are
  66  *          enabled.
  67  *
  68  * This macro copies a single simple value from kernel space to user
  69  * space.  It supports simple types like char and int, but not larger
  70  * data types like structures or arrays.
  71  *
  72  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
  73  * to the result of dereferencing @ptr.
  74  *
  75  * Returns zero on success, or -EFAULT on error.
  76  */
  77 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
  78
  79 /*
  80  * get_user: - Get a simple variable from user space.
  81  * @x:   Variable to store result.
  82  * @ptr: Source address, in user space.
  83  *
  84  * Context: User context only. This function may sleep if pagefaults are
  85  *          enabled.
  86  *
  87  * This macro copies a single simple variable from user space to kernel
  88  * space.  It supports simple types like char and int, but not larger
  89  * data types like structures or arrays.
  90  *
  91  * @ptr must have pointer-to-simple-variable type, and the result of
  92  * dereferencing @ptr must be assignable to @x without a cast.
  93  *
  94  * Returns zero on success, or -EFAULT on error.
  95  * On error, the variable @x is set to zero.
  96  */
  97 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
  98
  99 /*
 100  * __put_user: - Write a simple value into user space, with less checking.
 101  * @x:   Value to copy to user space.
 102  * @ptr: Destination address, in user space.
 103  *
 104  * Context: User context only. This function may sleep if pagefaults are
 105  *          enabled.
 106  *
 107  * This macro copies a single simple value from kernel space to user
 108  * space.  It supports simple types like char and int, but not larger
 109  * data types like structures or arrays.
 110  *
 111  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 112  * to the result of dereferencing @ptr.
 113  *
 114  * Caller must check the pointer with access_ok() before calling this
 115  * function.
 116  *
 117  * Returns zero on success, or -EFAULT on error.
 118  */
 119 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 120
 121 /*
 122  * __get_user: - Get a simple variable from user space, with less checking.
 123  * @x:   Variable to store result.
 124  * @ptr: Source address, in user space.
 125  *
 126  * Context: User context only. This function may sleep if pagefaults are
 127  *          enabled.
 128  *
 129  * This macro copies a single simple variable from user space to kernel
 130  * space.  It supports simple types like char and int, but not larger
 131  * data types like structures or arrays.
 132  *
 133  * @ptr must have pointer-to-simple-variable type, and the result of
 134  * dereferencing @ptr must be assignable to @x without a cast.
 135  *
 136  * Caller must check the pointer with access_ok() before calling this
 137  * function.
 138  *
 139  * Returns zero on success, or -EFAULT on error.
 140  * On error, the variable @x is set to zero.
 141  */
 142 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 143
 144 struct __large_struct { unsigned long buf[100]; };
 145 #define __m(x) (*(struct __large_struct __user *)(x))
 146
 147 /*
 148  * Yuck.  We need two variants, one for 64bit operation and one
 149  * for 32 bit mode and old iron.
 150  */
 151 extern void __get_user_unknown(void);
 152
 153 #define __get_user_common(val, size, ptr)                               \
 154 do {                                                                    \
 155         switch (size) {                                                 \
 156         case 1:                                                         \
 157                 __get_user_asm(val, "lb", ptr);                         \
 158                 break;                                                  \
 159         case 2:                                                         \
 160                 __get_user_asm(val, "lh", ptr);                         \
 161                  break;                                                 \
 162         case 4:                                                         \
 163                 __get_user_asm(val, "lw", ptr);                         \
 164                  break;                                                 \
 165         case 8:                                                         \
 166                 if (__copy_from_user((void *)&val, ptr, 8) == 0)        \
 167                         __gu_err = 0;                                   \
 168                 else                                                    \
 169                         __gu_err = -EFAULT;                             \
 170                 break;                                                  \
 171         default:                                                        \
 172                 __get_user_unknown();                                   \
 173                 break;                                                  \
 174         }                                                               \
 175 } while (0)
 176
 177 #define __get_user_nocheck(x, ptr, size)                                \
 178 ({                                                                      \
 179         long __gu_err = 0;                                              \
 180         __get_user_common((x), size, ptr);                              \
 181         __gu_err;                                                       \
 182 })
 183
 184 #define __get_user_check(x, ptr, size)                                  \
 185 ({                                                                      \
 186         long __gu_err = -EFAULT;                                        \
 187         const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);              \
 188                                                                         \
 189         if (likely(access_ok(VERIFY_READ, __gu_ptr, size)))             \
 190                 __get_user_common((x), size, __gu_ptr);                 \
 191         else                                                            \
 192                 (x) = 0;                                                \
 193                                                                         \
 194         __gu_err;                                                       \
 195 })
 196
 197 #define __get_user_asm(val, insn, addr)                                 \
 198 {                                                                       \
 199         long __gu_tmp;                                                  \
 200                                                                         \
 201         __asm__ __volatile__(                                           \
 202                 "1:" insn " %1, %3\n"                                   \
 203                 "2:\n"                                                  \
 204                 ".section .fixup,\"ax\"\n"                              \
 205                 "3:li   %0, %4\n"                                       \
 206                 "li     %1, 0\n"                                        \
 207                 "j      2b\n"                                           \
 208                 ".previous\n"                                           \
 209                 ".section __ex_table,\"a\"\n"                           \
 210                 ".word  1b, 3b\n"                                       \
 211                 ".previous\n"                                           \
 212                 : "=r" (__gu_err), "=r" (__gu_tmp)                      \
 213                 : "0" (0), "o" (__m(addr)), "i" (-EFAULT));             \
 214                                                                         \
 215                 (val) = (__typeof__(*(addr))) __gu_tmp;                 \
 216 }
 217
 218 /*
 219  * Yuck.  We need two variants, one for 64bit operation and one
 220  * for 32 bit mode and old iron.
 221  */
 222 #define __put_user_nocheck(val, ptr, size)                              \
 223 ({                                                                      \
 224         __typeof__(*(ptr)) __pu_val;                                    \
 225         long __pu_err = 0;                                              \
 226                                                                         \
 227         __pu_val = (val);                                               \
 228         switch (size) {                                                 \
 229         case 1:                                                         \
 230                 __put_user_asm("sb", ptr);                              \
 231                 break;                                                  \
 232         case 2:                                                         \
 233                 __put_user_asm("sh", ptr);                              \
 234                 break;                                                  \
 235         case 4:                                                         \
 236                 __put_user_asm("sw", ptr);                              \
 237                 break;                                                  \
 238         case 8:                                                         \
 239                 if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0)   \
 240                         __pu_err = 0;                                   \
 241                 else                                                    \
 242                         __pu_err = -EFAULT;                             \
 243                 break;                                                  \
 244         default:                                                        \
 245                  __put_user_unknown();                                  \
 246                  break;                                                 \
 247         }                                                               \
 248         __pu_err;                                                       \
 249 })
 250
 251
 252 #define __put_user_check(val, ptr, size)                                \
 253 ({                                                                      \
 254         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 255         __typeof__(*(ptr)) __pu_val = (val);                            \
 256         long __pu_err = -EFAULT;                                        \
 257                                                                         \
 258         if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) {         \
 259                 switch (size) {                                         \
 260                 case 1:                                                 \
 261                         __put_user_asm("sb", __pu_addr);                \
 262                         break;                                          \
 263                 case 2:                                                 \
 264                         __put_user_asm("sh", __pu_addr);                \
 265                         break;                                          \
 266                 case 4:                                                 \
 267                         __put_user_asm("sw", __pu_addr);                \
 268                         break;                                          \
 269                 case 8:                                                 \
 270                         if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
 271                                 __pu_err = 0;                           \
 272                         else                                            \
 273                                 __pu_err = -EFAULT;                     \
 274                         break;                                          \
 275                 default:                                                \
 276                         __put_user_unknown();                           \
 277                         break;                                          \
 278                 }                                                       \
 279         }                                                               \
 280         __pu_err;                                                       \
 281 })
 282
 283 #define __put_user_asm(insn, ptr)                                       \
 284         __asm__ __volatile__(                                           \
 285                 "1:" insn " %2, %3\n"                                   \
 286                 "2:\n"                                                  \
 287                 ".section .fixup,\"ax\"\n"                              \
 288                 "3:li %0, %4\n"                                         \
 289                 "j 2b\n"                                                \
 290                 ".previous\n"                                           \
 291                 ".section __ex_table,\"a\"\n"                           \
 292                 ".word 1b, 3b\n"                                        \
 293                 ".previous\n"                                           \
 294                 : "=r" (__pu_err)                                       \
 295                 : "0" (0), "r" (__pu_val), "o" (__m(ptr)),              \
 296                   "i" (-EFAULT));
 297
 298 extern void __put_user_unknown(void);
 299 extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
 300
 301 static inline unsigned long
 302 copy_from_user(void *to, const void *from, unsigned long len)
 303 {
 304         unsigned long res = len;
 305
 306         if (likely(access_ok(VERIFY_READ, from, len)))
 307                 res = __copy_tofrom_user(to, from, len);
 308
 309         if (unlikely(res))
 310                 memset(to + (len - res), 0, res);
 311
 312         return res;
 313 }
 314
 315 static inline unsigned long
 316 copy_to_user(void *to, const void *from, unsigned long len)
 317 {
 318         if (likely(access_ok(VERIFY_WRITE, to, len)))
 319                 len = __copy_tofrom_user(to, from, len);
 320
 321         return len;
 322 }
 323
 324 static inline unsigned long
 325 __copy_from_user(void *to, const void *from, unsigned long len)
 326 {
 327         unsigned long left = __copy_tofrom_user(to, from, len);
 328         if (unlikely(left))
 329                 memset(to + (len - left), 0, left);
 330         return left;
 331 }
 332
 333 #define __copy_to_user(to, from, len)           \
 334                 __copy_tofrom_user((to), (from), (len))
 335
 336 static inline unsigned long
 337 __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
 338 {
 339         return __copy_to_user(to, from, len);
 340 }
 341
 342 static inline unsigned long
 343 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
 344 {
 345         return __copy_tofrom_user(to, from, len);
 346 }
 347
 348 #define __copy_in_user(to, from, len)   __copy_tofrom_user(to, from, len)
 349
 350 static inline unsigned long
 351 copy_in_user(void *to, const void *from, unsigned long len)
 352 {
 353         if (access_ok(VERIFY_READ, from, len) &&
 354                       access_ok(VERFITY_WRITE, to, len))
 355                 return __copy_tofrom_user(to, from, len);
 356 }
 357
 358 /*
 359  * __clear_user: - Zero a block of memory in user space, with less checking.
 360  * @to:   Destination address, in user space.
 361  * @n:    Number of bytes to zero.
 362  *
 363  * Zero a block of memory in user space.  Caller must check
 364  * the specified block with access_ok() before calling this function.
 365  *
 366  * Returns number of bytes that could not be cleared.
 367  * On success, this will be zero.
 368  */
 369 extern unsigned long __clear_user(void __user *src, unsigned long size);
 370
 371 static inline unsigned long clear_user(char *src, unsigned long size)
 372 {
 373         if (access_ok(VERIFY_WRITE, src, size))
 374                 return __clear_user(src, size);
 375
 376         return -EFAULT;
 377 }
 378 /*
 379  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 380  * @dst:   Destination address, in kernel space.  This buffer must be at
 381  *         least @count bytes long.
 382  * @src:   Source address, in user space.
 383  * @count: Maximum number of bytes to copy, including the trailing NUL.
 384  *
 385  * Copies a NUL-terminated string from userspace to kernel space.
 386  * Caller must check the specified block with access_ok() before calling
 387  * this function.
 388  *
 389  * On success, returns the length of the string (not including the trailing
 390  * NUL).
 391  *
 392  * If access to userspace fails, returns -EFAULT (some data may have been
 393  * copied).
 394  *
 395  * If @count is smaller than the length of the string, copies @count bytes
 396  * and returns @count.
 397  */
 398 extern int __strncpy_from_user(char *dst, const char *src, long len);
 399
 400 static inline int strncpy_from_user(char *dst, const char *src, long len)
 401 {
 402         if (access_ok(VERIFY_READ, src, 1))
 403                 return __strncpy_from_user(dst, src, len);
 404
 405         return -EFAULT;
 406 }
 407
 408 extern int __strlen_user(const char *src);
 409 static inline long strlen_user(const char __user *src)
 410 {
 411         return __strlen_user(src);
 412 }
 413
 414 extern int __strnlen_user(const char *str, long len);
 415 static inline long strnlen_user(const char __user *str, long len)
 416 {
 417         if (!access_ok(VERIFY_READ, str, 0))
 418                 return 0;
 419         else
 420                 return __strnlen_user(str, len);
 421 }
 422
 423 struct exception_table_entry {
 424         unsigned long insn;
 425         unsigned long fixup;
 426 };
 427
 428 extern int fixup_exception(struct pt_regs *regs);
 429
 430 #endif /* __SCORE_UACCESS_H */
 431