arch/cris/include/asm/uaccess.h

   1 /*
   2  * Authors:    Bjorn Wesen (bjornw@axis.com)
   3  *             Hans-Peter Nilsson (hp@axis.com)
   4  */
   5
   6 /* Asm:s have been tweaked (within the domain of correctness) to give
   7    satisfactory results for "gcc version 2.96 20000427 (experimental)".
   8
   9    Check regularly...
  10
  11    Register $r9 is chosen for temporaries, being a call-clobbered register
  12    first in line to be used (notably for local blocks), not colliding with
  13    parameter registers.  */
  14
  15 #ifndef _CRIS_UACCESS_H
  16 #define _CRIS_UACCESS_H
  17
  18 #ifndef __ASSEMBLY__
  19 #include <linux/sched.h>
  20 #include <linux/errno.h>
  21 #include <asm/processor.h>
  22 #include <asm/page.h>
  23
  24 #define VERIFY_READ     0
  25 #define VERIFY_WRITE    1
  26
  27 /*
  28  * The fs value determines whether argument validity checking should be
  29  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  30  * get_fs() == KERNEL_DS, checking is bypassed.
  31  *
  32  * For historical reasons, these macros are grossly misnamed.
  33  */
  34
  35 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  36
  37 /* addr_limit is the maximum accessible address for the task. we misuse
  38  * the KERNEL_DS and USER_DS values to both assign and compare the
  39  * addr_limit values through the equally misnamed get/set_fs macros.
  40  * (see above)
  41  */
  42
  43 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  44 #define USER_DS         MAKE_MM_SEG(TASK_SIZE)
  45
  46 #define get_ds()        (KERNEL_DS)
  47 #define get_fs()        (current_thread_info()->addr_limit)
  48 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  49
  50 #define segment_eq(a, b)        ((a).seg == (b).seg)
  51
  52 #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
  53 #define __user_ok(addr, size) \
  54         (((size) <= TASK_SIZE) && ((addr) <= TASK_SIZE-(size)))
  55 #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
  56 #define access_ok(type, addr, size) __access_ok((unsigned long)(addr), (size))
  57
  58 #include <arch/uaccess.h>
  59
  60 /*
  61  * The exception table consists of pairs of addresses: the first is the
  62  * address of an instruction that is allowed to fault, and the second is
  63  * the address at which the program should continue.  No registers are
  64  * modified, so it is entirely up to the continuation code to figure out
  65  * what to do.
  66  *
  67  * All the routines below use bits of fixup code that are out of line
  68  * with the main instruction path.  This means when everything is well,
  69  * we don't even have to jump over them.  Further, they do not intrude
  70  * on our cache or tlb entries.
  71  */
  72
  73 struct exception_table_entry {
  74         unsigned long insn, fixup;
  75 };
  76
  77 /*
  78  * These are the main single-value transfer routines.  They automatically
  79  * use the right size if we just have the right pointer type.
  80  *
  81  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  82  * and yet we don't want to do any pointers, because that is too much
  83  * of a performance impact. Thus we have a few rather ugly macros here,
  84  * and hide all the ugliness from the user.
  85  *
  86  * The "__xxx" versions of the user access functions are versions that
  87  * do not verify the address space, that must have been done previously
  88  * with a separate "access_ok()" call (this is used when we do multiple
  89  * accesses to the same area of user memory).
  90  *
  91  * As we use the same address space for kernel and user data on
  92  * CRIS, we can just do these as direct assignments.  (Of course, the
  93  * exception handling means that it's no longer "just"...)
  94  */
  95 #define get_user(x, ptr) \
  96         __get_user_check((x), (ptr), sizeof(*(ptr)))
  97 #define put_user(x, ptr) \
  98         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  99
 100 #define __get_user(x, ptr) \
 101         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 102 #define __put_user(x, ptr) \
 103         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 104
 105 extern long __put_user_bad(void);
 106
 107 #define __put_user_size(x, ptr, size, retval)                           \
 108 do {                                                                    \
 109         retval = 0;                                                     \
 110         switch (size) {                                                 \
 111         case 1:                                                         \
 112                 __put_user_asm(x, ptr, retval, "move.b");               \
 113                 break;                                                  \
 114         case 2:                                                         \
 115                 __put_user_asm(x, ptr, retval, "move.w");               \
 116                 break;                                                  \
 117         case 4:                                                         \
 118                 __put_user_asm(x, ptr, retval, "move.d");               \
 119                 break;                                                  \
 120         case 8:                                                         \
 121                 __put_user_asm_64(x, ptr, retval);                      \
 122                 break;                                                  \
 123         default:                                                        \
 124                 __put_user_bad();                                       \
 125         }                                                               \
 126 } while (0)
 127
 128 #define __get_user_size(x, ptr, size, retval)                           \
 129 do {                                                                    \
 130         retval = 0;                                                     \
 131         switch (size) {                                                 \
 132         case 1:                                                         \
 133                 __get_user_asm(x, ptr, retval, "move.b");               \
 134                 break;                                                  \
 135         case 2:                                                         \
 136                 __get_user_asm(x, ptr, retval, "move.w");               \
 137                 break;                                                  \
 138         case 4:                                                         \
 139                 __get_user_asm(x, ptr, retval, "move.d");               \
 140                 break;                                                  \
 141         case 8:                                                         \
 142                 __get_user_asm_64(x, ptr, retval);                      \
 143                 break;                                                  \
 144         default:                                                        \
 145                 (x) = __get_user_bad();                                 \
 146         }                                                               \
 147 } while (0)
 148
 149 #define __put_user_nocheck(x, ptr, size)                \
 150 ({                                                      \
 151         long __pu_err;                                  \
 152         __put_user_size((x), (ptr), (size), __pu_err);  \
 153         __pu_err;                                       \
 154 })
 155
 156 #define __put_user_check(x, ptr, size)                                  \
 157 ({                                                                      \
 158         long __pu_err = -EFAULT;                                        \
 159         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 160         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 161                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 162         __pu_err;                                                       \
 163 })
 164
 165 struct __large_struct { unsigned long buf[100]; };
 166 #define __m(x) (*(struct __large_struct *)(x))
 167
 168
 169
 170 #define __get_user_nocheck(x, ptr, size)                        \
 171 ({                                                              \
 172         long __gu_err, __gu_val;                                \
 173         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 174         (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 175         __gu_err;                                               \
 176 })
 177
 178 #define __get_user_check(x, ptr, size)                                  \
 179 ({                                                                      \
 180         long __gu_err = -EFAULT, __gu_val = 0;                          \
 181         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 182         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 183                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 184         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 185         __gu_err;                                                       \
 186 })
 187
 188 extern long __get_user_bad(void);
 189
 190 /* More complex functions.  Most are inline, but some call functions that
 191    live in lib/usercopy.c  */
 192
 193 extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
 194 extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
 195 extern unsigned long __do_clear_user(void __user *to, unsigned long n);
 196
 197 static inline long
 198 __strncpy_from_user(char *dst, const char __user *src, long count)
 199 {
 200         return __do_strncpy_from_user(dst, src, count);
 201 }
 202
 203 static inline long
 204 strncpy_from_user(char *dst, const char __user *src, long count)
 205 {
 206         long res = -EFAULT;
 207
 208         if (access_ok(VERIFY_READ, src, 1))
 209                 res = __do_strncpy_from_user(dst, src, count);
 210         return res;
 211 }
 212
 213
 214 /* Note that these expand awfully if made into switch constructs, so
 215    don't do that.  */
 216
 217 static inline unsigned long
 218 __constant_copy_from_user(void *to, const void __user *from, unsigned long n)
 219 {
 220         unsigned long ret = 0;
 221
 222         if (n == 0)
 223                 ;
 224         else if (n == 1)
 225                 __asm_copy_from_user_1(to, from, ret);
 226         else if (n == 2)
 227                 __asm_copy_from_user_2(to, from, ret);
 228         else if (n == 3)
 229                 __asm_copy_from_user_3(to, from, ret);
 230         else if (n == 4)
 231                 __asm_copy_from_user_4(to, from, ret);
 232         else if (n == 5)
 233                 __asm_copy_from_user_5(to, from, ret);
 234         else if (n == 6)
 235                 __asm_copy_from_user_6(to, from, ret);
 236         else if (n == 7)
 237                 __asm_copy_from_user_7(to, from, ret);
 238         else if (n == 8)
 239                 __asm_copy_from_user_8(to, from, ret);
 240         else if (n == 9)
 241                 __asm_copy_from_user_9(to, from, ret);
 242         else if (n == 10)
 243                 __asm_copy_from_user_10(to, from, ret);
 244         else if (n == 11)
 245                 __asm_copy_from_user_11(to, from, ret);
 246         else if (n == 12)
 247                 __asm_copy_from_user_12(to, from, ret);
 248         else if (n == 13)
 249                 __asm_copy_from_user_13(to, from, ret);
 250         else if (n == 14)
 251                 __asm_copy_from_user_14(to, from, ret);
 252         else if (n == 15)
 253                 __asm_copy_from_user_15(to, from, ret);
 254         else if (n == 16)
 255                 __asm_copy_from_user_16(to, from, ret);
 256         else if (n == 20)
 257                 __asm_copy_from_user_20(to, from, ret);
 258         else if (n == 24)
 259                 __asm_copy_from_user_24(to, from, ret);
 260         else
 261                 ret = __copy_user_zeroing(to, from, n);
 262
 263         return ret;
 264 }
 265
 266 /* Ditto, don't make a switch out of this.  */
 267
 268 static inline unsigned long
 269 __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
 270 {
 271         unsigned long ret = 0;
 272
 273         if (n == 0)
 274                 ;
 275         else if (n == 1)
 276                 __asm_copy_to_user_1(to, from, ret);
 277         else if (n == 2)
 278                 __asm_copy_to_user_2(to, from, ret);
 279         else if (n == 3)
 280                 __asm_copy_to_user_3(to, from, ret);
 281         else if (n == 4)
 282                 __asm_copy_to_user_4(to, from, ret);
 283         else if (n == 5)
 284                 __asm_copy_to_user_5(to, from, ret);
 285         else if (n == 6)
 286                 __asm_copy_to_user_6(to, from, ret);
 287         else if (n == 7)
 288                 __asm_copy_to_user_7(to, from, ret);
 289         else if (n == 8)
 290                 __asm_copy_to_user_8(to, from, ret);
 291         else if (n == 9)
 292                 __asm_copy_to_user_9(to, from, ret);
 293         else if (n == 10)
 294                 __asm_copy_to_user_10(to, from, ret);
 295         else if (n == 11)
 296                 __asm_copy_to_user_11(to, from, ret);
 297         else if (n == 12)
 298                 __asm_copy_to_user_12(to, from, ret);
 299         else if (n == 13)
 300                 __asm_copy_to_user_13(to, from, ret);
 301         else if (n == 14)
 302                 __asm_copy_to_user_14(to, from, ret);
 303         else if (n == 15)
 304                 __asm_copy_to_user_15(to, from, ret);
 305         else if (n == 16)
 306                 __asm_copy_to_user_16(to, from, ret);
 307         else if (n == 20)
 308                 __asm_copy_to_user_20(to, from, ret);
 309         else if (n == 24)
 310                 __asm_copy_to_user_24(to, from, ret);
 311         else
 312                 ret = __copy_user(to, from, n);
 313
 314         return ret;
 315 }
 316
 317 /* No switch, please.  */
 318
 319 static inline unsigned long
 320 __constant_clear_user(void __user *to, unsigned long n)
 321 {
 322         unsigned long ret = 0;
 323
 324         if (n == 0)
 325                 ;
 326         else if (n == 1)
 327                 __asm_clear_1(to, ret);
 328         else if (n == 2)
 329                 __asm_clear_2(to, ret);
 330         else if (n == 3)
 331                 __asm_clear_3(to, ret);
 332         else if (n == 4)
 333                 __asm_clear_4(to, ret);
 334         else if (n == 8)
 335                 __asm_clear_8(to, ret);
 336         else if (n == 12)
 337                 __asm_clear_12(to, ret);
 338         else if (n == 16)
 339                 __asm_clear_16(to, ret);
 340         else if (n == 20)
 341                 __asm_clear_20(to, ret);
 342         else if (n == 24)
 343                 __asm_clear_24(to, ret);
 344         else
 345                 ret = __do_clear_user(to, n);
 346
 347         return ret;
 348 }
 349
 350
 351 static inline size_t clear_user(void __user *to, size_t n)
 352 {
 353         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 354                 return n;
 355         if (__builtin_constant_p(n))
 356                 return __constant_clear_user(to, n);
 357         else
 358                 return __do_clear_user(to, n);
 359 }
 360
 361 static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
 362 {
 363         if (unlikely(!access_ok(VERIFY_READ, from, n))) {
 364                 memset(to, 0, n);
 365                 return n;
 366         }
 367         if (__builtin_constant_p(n))
 368                 return __constant_copy_from_user(to, from, n);
 369         else
 370                 return __copy_user_zeroing(to, from, n);
 371 }
 372
 373 static inline size_t copy_to_user(void __user *to, const void *from, size_t n)
 374 {
 375         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 376                 return n;
 377         if (__builtin_constant_p(n))
 378                 return __constant_copy_to_user(to, from, n);
 379         else
 380                 return __copy_user(to, from, n);
 381 }
 382
 383 /* We let the __ versions of copy_from/to_user inline, because they're often
 384  * used in fast paths and have only a small space overhead.
 385  */
 386
 387 static inline unsigned long
 388 __generic_copy_from_user_nocheck(void *to, const void __user *from,
 389                                  unsigned long n)
 390 {
 391         return __copy_user_zeroing(to, from, n);
 392 }
 393
 394 static inline unsigned long
 395 __generic_copy_to_user_nocheck(void __user *to, const void *from,
 396                                unsigned long n)
 397 {
 398         return __copy_user(to, from, n);
 399 }
 400
 401 static inline unsigned long
 402 __generic_clear_user_nocheck(void __user *to, unsigned long n)
 403 {
 404         return __do_clear_user(to, n);
 405 }
 406
 407 /* without checking */
 408
 409 #define __copy_to_user(to, from, n) \
 410         __generic_copy_to_user_nocheck((to), (from), (n))
 411 #define __copy_from_user(to, from, n) \
 412         __generic_copy_from_user_nocheck((to), (from), (n))
 413 #define __copy_to_user_inatomic __copy_to_user
 414 #define __copy_from_user_inatomic __copy_from_user
 415 #define __clear_user(to, n) __generic_clear_user_nocheck((to), (n))
 416
 417 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 418
 419 #endif  /* __ASSEMBLY__ */
 420
 421 #endif  /* _CRIS_UACCESS_H */