arch/score/include/asm/uaccess.h

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