git.oblomov.eu Git - linux-2.6/blob - include/asm-mips/uaccess.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  */
   9 #ifndef _ASM_UACCESS_H
  10 #define _ASM_UACCESS_H
  11
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/thread_info.h>
  15 #include <asm-generic/uaccess.h>
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24 #ifdef CONFIG_32BIT
  25
  26 #define __UA_LIMIT      0x80000000UL
  27
  28 #define __UA_ADDR       ".word"
  29 #define __UA_LA         "la"
  30 #define __UA_ADDU       "addu"
  31 #define __UA_t0         "$8"
  32 #define __UA_t1         "$9"
  33
  34 #endif /* CONFIG_32BIT */
  35
  36 #ifdef CONFIG_64BIT
  37
  38 #define __UA_LIMIT      (- TASK_SIZE)
  39
  40 #define __UA_ADDR       ".dword"
  41 #define __UA_LA         "dla"
  42 #define __UA_ADDU       "daddu"
  43 #define __UA_t0         "$12"
  44 #define __UA_t1         "$13"
  45
  46 #endif /* CONFIG_64BIT */
  47
  48 /*
  49  * USER_DS is a bitmask that has the bits set that may not be set in a valid
  50  * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
  51  * the arithmetic we're doing only works if the limit is a power of two, so
  52  * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
  53  * address in this range it's the process's problem, not ours :-)
  54  */
  55
  56 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  57 #define USER_DS         ((mm_segment_t) { __UA_LIMIT })
  58
  59 #define VERIFY_READ    0
  60 #define VERIFY_WRITE   1
  61
  62 #define get_ds()        (KERNEL_DS)
  63 #define get_fs()        (current_thread_info()->addr_limit)
  64 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  65
  66 #define segment_eq(a, b)        ((a).seg == (b).seg)
  67
  68
  69 /*
  70  * Is a address valid? This does a straighforward calculation rather
  71  * than tests.
  72  *
  73  * Address valid if:
  74  *  - "addr" doesn't have any high-bits set
  75  *  - AND "size" doesn't have any high-bits set
  76  *  - AND "addr+size" doesn't have any high-bits set
  77  *  - OR we are in kernel mode.
  78  *
  79  * __ua_size() is a trick to avoid runtime checking of positive constant
  80  * sizes; for those we already know at compile time that the size is ok.
  81  */
  82 #define __ua_size(size)                                                 \
  83         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  84
  85 /*
  86  * access_ok: - Checks if a user space pointer is valid
  87  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  88  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  89  *        to write to a block, it is always safe to read from it.
  90  * @addr: User space pointer to start of block to check
  91  * @size: Size of block to check
  92  *
  93  * Context: User context only.  This function may sleep.
  94  *
  95  * Checks if a pointer to a block of memory in user space is valid.
  96  *
  97  * Returns true (nonzero) if the memory block may be valid, false (zero)
  98  * if it is definitely invalid.
  99  *
 100  * Note that, depending on architecture, this function probably just
 101  * checks that the pointer is in the user space range - after calling
 102  * this function, memory access functions may still return -EFAULT.
 103  */
 104
 105 #define __access_mask get_fs().seg
 106
 107 #define __access_ok(addr, size, mask)                                   \
 108         (((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)
 109
 110 #define access_ok(type, addr, size)                                     \
 111         likely(__access_ok((unsigned long)(addr), (size), __access_mask))
 112
 113 /*
 114  * put_user: - Write a simple value into user space.
 115  * @x:   Value to copy to user space.
 116  * @ptr: Destination address, in user space.
 117  *
 118  * Context: User context only.  This function may sleep.
 119  *
 120  * This macro copies a single simple value from kernel space to user
 121  * space.  It supports simple types like char and int, but not larger
 122  * data types like structures or arrays.
 123  *
 124  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 125  * to the result of dereferencing @ptr.
 126  *
 127  * Returns zero on success, or -EFAULT on error.
 128  */
 129 #define put_user(x,ptr) \
 130         __put_user_check((x), (ptr), sizeof(*(ptr)))
 131
 132 /*
 133  * get_user: - Get a simple variable from user space.
 134  * @x:   Variable to store result.
 135  * @ptr: Source address, in user space.
 136  *
 137  * Context: User context only.  This function may sleep.
 138  *
 139  * This macro copies a single simple variable from user space to kernel
 140  * space.  It supports simple types like char and int, but not larger
 141  * data types like structures or arrays.
 142  *
 143  * @ptr must have pointer-to-simple-variable type, and the result of
 144  * dereferencing @ptr must be assignable to @x without a cast.
 145  *
 146  * Returns zero on success, or -EFAULT on error.
 147  * On error, the variable @x is set to zero.
 148  */
 149 #define get_user(x,ptr) \
 150         __get_user_check((x), (ptr), sizeof(*(ptr)))
 151
 152 /*
 153  * __put_user: - Write a simple value into user space, with less checking.
 154  * @x:   Value to copy to user space.
 155  * @ptr: Destination address, in user space.
 156  *
 157  * Context: User context only.  This function may sleep.
 158  *
 159  * This macro copies a single simple value from kernel space to user
 160  * space.  It supports simple types like char and int, but not larger
 161  * data types like structures or arrays.
 162  *
 163  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 164  * to the result of dereferencing @ptr.
 165  *
 166  * Caller must check the pointer with access_ok() before calling this
 167  * function.
 168  *
 169  * Returns zero on success, or -EFAULT on error.
 170  */
 171 #define __put_user(x,ptr) \
 172         __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 173
 174 /*
 175  * __get_user: - Get a simple variable from user space, with less checking.
 176  * @x:   Variable to store result.
 177  * @ptr: Source address, in user space.
 178  *
 179  * Context: User context only.  This function may sleep.
 180  *
 181  * This macro copies a single simple variable from user space to kernel
 182  * space.  It supports simple types like char and int, but not larger
 183  * data types like structures or arrays.
 184  *
 185  * @ptr must have pointer-to-simple-variable type, and the result of
 186  * dereferencing @ptr must be assignable to @x without a cast.
 187  *
 188  * Caller must check the pointer with access_ok() before calling this
 189  * function.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  * On error, the variable @x is set to zero.
 193  */
 194 #define __get_user(x,ptr) \
 195         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 196
 197 struct __large_struct { unsigned long buf[100]; };
 198 #define __m(x) (*(struct __large_struct __user *)(x))
 199
 200 /*
 201  * Yuck.  We need two variants, one for 64bit operation and one
 202  * for 32 bit mode and old iron.
 203  */
 204 #ifdef CONFIG_32BIT
 205 #define __GET_USER_DW(val, ptr) __get_user_asm_ll32(val, ptr)
 206 #endif
 207 #ifdef CONFIG_64BIT
 208 #define __GET_USER_DW(val, ptr) __get_user_asm(val, "ld", ptr)
 209 #endif
 210
 211 extern void __get_user_unknown(void);
 212
 213 #define __get_user_common(val, size, ptr)                               \
 214 do {                                                                    \
 215         switch (size) {                                                 \
 216         case 1: __get_user_asm(val, "lb", ptr); break;                  \
 217         case 2: __get_user_asm(val, "lh", ptr); break;                  \
 218         case 4: __get_user_asm(val, "lw", ptr); break;                  \
 219         case 8: __GET_USER_DW(val, ptr); break;                         \
 220         default: __get_user_unknown(); break;                           \
 221         }                                                               \
 222 } while (0)
 223
 224 #define __get_user_nocheck(x, ptr, size)                                \
 225 ({                                                                      \
 226         long __gu_err;                                                  \
 227                                                                         \
 228         __get_user_common((x), size, ptr);                              \
 229         __gu_err;                                                       \
 230 })
 231
 232 #define __get_user_check(x, ptr, size)                                  \
 233 ({                                                                      \
 234         long __gu_err = -EFAULT;                                        \
 235         const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);             \
 236                                                                         \
 237         if (likely(access_ok(VERIFY_READ,  __gu_ptr, size)))            \
 238                 __get_user_common((x), size, __gu_ptr);                 \
 239                                                                         \
 240         __gu_err;                                                       \
 241 })
 242
 243 #define __get_user_asm(val, insn, addr)                                 \
 244 {                                                                       \
 245         long __gu_tmp;                                                  \
 246                                                                         \
 247         __asm__ __volatile__(                                           \
 248         "1:     " insn "        %1, %3                          \n"     \
 249         "2:                                                     \n"     \
 250         "       .section .fixup,\"ax\"                          \n"     \
 251         "3:     li      %0, %4                                  \n"     \
 252         "       j       2b                                      \n"     \
 253         "       .previous                                       \n"     \
 254         "       .section __ex_table,\"a\"                       \n"     \
 255         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 256         "       .previous                                       \n"     \
 257         : "=r" (__gu_err), "=r" (__gu_tmp)                              \
 258         : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                     \
 259                                                                         \
 260         (val) = (__typeof__(*(addr))) __gu_tmp;                         \
 261 }
 262
 263 /*
 264  * Get a long long 64 using 32 bit registers.
 265  */
 266 #define __get_user_asm_ll32(val, addr)                                  \
 267 {                                                                       \
 268         union {                                                         \
 269                 unsigned long long      l;                              \
 270                 __typeof__(*(addr))     t;                              \
 271         } __gu_tmp;                                                     \
 272                                                                         \
 273         __asm__ __volatile__(                                           \
 274         "1:     lw      %1, (%3)                                \n"     \
 275         "2:     lw      %D1, 4(%3)                              \n"     \
 276         "3:     .section        .fixup,\"ax\"                   \n"     \
 277         "4:     li      %0, %4                                  \n"     \
 278         "       move    %1, $0                                  \n"     \
 279         "       move    %D1, $0                                 \n"     \
 280         "       j       3b                                      \n"     \
 281         "       .previous                                       \n"     \
 282         "       .section        __ex_table,\"a\"                \n"     \
 283         "       " __UA_ADDR "   1b, 4b                          \n"     \
 284         "       " __UA_ADDR "   2b, 4b                          \n"     \
 285         "       .previous                                       \n"     \
 286         : "=r" (__gu_err), "=&r" (__gu_tmp.l)                           \
 287         : "0" (0), "r" (addr), "i" (-EFAULT));                          \
 288                                                                         \
 289         (val) = __gu_tmp.t;                                             \
 290 }
 291
 292 /*
 293  * Yuck.  We need two variants, one for 64bit operation and one
 294  * for 32 bit mode and old iron.
 295  */
 296 #ifdef CONFIG_32BIT
 297 #define __PUT_USER_DW(ptr) __put_user_asm_ll32(ptr)
 298 #endif
 299 #ifdef CONFIG_64BIT
 300 #define __PUT_USER_DW(ptr) __put_user_asm("sd", ptr)
 301 #endif
 302
 303 #define __put_user_nocheck(x, ptr, size)                                \
 304 ({                                                                      \
 305         __typeof__(*(ptr)) __pu_val;                                    \
 306         long __pu_err = 0;                                              \
 307                                                                         \
 308         __pu_val = (x);                                                 \
 309         switch (size) {                                                 \
 310         case 1: __put_user_asm("sb", ptr); break;                       \
 311         case 2: __put_user_asm("sh", ptr); break;                       \
 312         case 4: __put_user_asm("sw", ptr); break;                       \
 313         case 8: __PUT_USER_DW(ptr); break;                              \
 314         default: __put_user_unknown(); break;                           \
 315         }                                                               \
 316         __pu_err;                                                       \
 317 })
 318
 319 #define __put_user_check(x, ptr, size)                                  \
 320 ({                                                                      \
 321         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 322         __typeof__(*(ptr)) __pu_val = (x);                              \
 323         long __pu_err = -EFAULT;                                        \
 324                                                                         \
 325         if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {        \
 326                 switch (size) {                                         \
 327                 case 1: __put_user_asm("sb", __pu_addr); break;         \
 328                 case 2: __put_user_asm("sh", __pu_addr); break;         \
 329                 case 4: __put_user_asm("sw", __pu_addr); break;         \
 330                 case 8: __PUT_USER_DW(__pu_addr); break;                \
 331                 default: __put_user_unknown(); break;                   \
 332                 }                                                       \
 333         }                                                               \
 334         __pu_err;                                                       \
 335 })
 336
 337 #define __put_user_asm(insn, ptr)                                       \
 338 {                                                                       \
 339         __asm__ __volatile__(                                           \
 340         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 341         "2:                                                     \n"     \
 342         "       .section        .fixup,\"ax\"                   \n"     \
 343         "3:     li      %0, %4                                  \n"     \
 344         "       j       2b                                      \n"     \
 345         "       .previous                                       \n"     \
 346         "       .section        __ex_table,\"a\"                \n"     \
 347         "       " __UA_ADDR "   1b, 3b                          \n"     \
 348         "       .previous                                       \n"     \
 349         : "=r" (__pu_err)                                               \
 350         : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                     \
 351           "i" (-EFAULT));                                               \
 352 }
 353
 354 #define __put_user_asm_ll32(ptr)                                        \
 355 {                                                                       \
 356         __asm__ __volatile__(                                           \
 357         "1:     sw      %2, (%3)        # __put_user_asm_ll32   \n"     \
 358         "2:     sw      %D2, 4(%3)                              \n"     \
 359         "3:                                                     \n"     \
 360         "       .section        .fixup,\"ax\"                   \n"     \
 361         "4:     li      %0, %4                                  \n"     \
 362         "       j       3b                                      \n"     \
 363         "       .previous                                       \n"     \
 364         "       .section        __ex_table,\"a\"                \n"     \
 365         "       " __UA_ADDR "   1b, 4b                          \n"     \
 366         "       " __UA_ADDR "   2b, 4b                          \n"     \
 367         "       .previous"                                              \
 368         : "=r" (__pu_err)                                               \
 369         : "0" (0), "r" (__pu_val), "r" (ptr),                           \
 370           "i" (-EFAULT));                                               \
 371 }
 372
 373 extern void __put_user_unknown(void);
 374
 375 /*
 376  * We're generating jump to subroutines which will be outside the range of
 377  * jump instructions
 378  */
 379 #ifdef MODULE
 380 #define __MODULE_JAL(destination)                                       \
 381         ".set\tnoat\n\t"                                                \
 382         __UA_LA "\t$1, " #destination "\n\t"                            \
 383         "jalr\t$1\n\t"                                                  \
 384         ".set\tat\n\t"
 385 #else
 386 #define __MODULE_JAL(destination)                                       \
 387         "jal\t" #destination "\n\t"
 388 #endif
 389
 390 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 391
 392 #define __invoke_copy_to_user(to, from, n)                              \
 393 ({                                                                      \
 394         register void __user *__cu_to_r __asm__("$4");                  \
 395         register const void *__cu_from_r __asm__("$5");                 \
 396         register long __cu_len_r __asm__("$6");                         \
 397                                                                         \
 398         __cu_to_r = (to);                                               \
 399         __cu_from_r = (from);                                           \
 400         __cu_len_r = (n);                                               \
 401         __asm__ __volatile__(                                           \
 402         __MODULE_JAL(__copy_user)                                       \
 403         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 404         :                                                               \
 405         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 406           "memory");                                                    \
 407         __cu_len_r;                                                     \
 408 })
 409
 410 /*
 411  * __copy_to_user: - Copy a block of data into user space, with less checking.
 412  * @to:   Destination address, in user space.
 413  * @from: Source address, in kernel space.
 414  * @n:    Number of bytes to copy.
 415  *
 416  * Context: User context only.  This function may sleep.
 417  *
 418  * Copy data from kernel space to user space.  Caller must check
 419  * the specified block with access_ok() before calling this function.
 420  *
 421  * Returns number of bytes that could not be copied.
 422  * On success, this will be zero.
 423  */
 424 #define __copy_to_user(to, from, n)                                     \
 425 ({                                                                      \
 426         void __user *__cu_to;                                           \
 427         const void *__cu_from;                                          \
 428         long __cu_len;                                                  \
 429                                                                         \
 430         might_sleep();                                                  \
 431         __cu_to = (to);                                                 \
 432         __cu_from = (from);                                             \
 433         __cu_len = (n);                                                 \
 434         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 435         __cu_len;                                                       \
 436 })
 437
 438 extern size_t __copy_user_inatomic(void *__to, const void *__from, size_t __n);
 439
 440 #define __copy_to_user_inatomic(to, from, n)                            \
 441 ({                                                                      \
 442         void __user *__cu_to;                                           \
 443         const void *__cu_from;                                          \
 444         long __cu_len;                                                  \
 445                                                                         \
 446         __cu_to = (to);                                                 \
 447         __cu_from = (from);                                             \
 448         __cu_len = (n);                                                 \
 449         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 450         __cu_len;                                                       \
 451 })
 452
 453 #define __copy_from_user_inatomic(to, from, n)                          \
 454 ({                                                                      \
 455         void *__cu_to;                                                  \
 456         const void __user *__cu_from;                                   \
 457         long __cu_len;                                                  \
 458                                                                         \
 459         __cu_to = (to);                                                 \
 460         __cu_from = (from);                                             \
 461         __cu_len = (n);                                                 \
 462         __cu_len = __invoke_copy_from_user_inatomic(__cu_to, __cu_from, \
 463                                                     __cu_len);          \
 464         __cu_len;                                                       \
 465 })
 466
 467 /*
 468  * copy_to_user: - Copy a block of data into user space.
 469  * @to:   Destination address, in user space.
 470  * @from: Source address, in kernel space.
 471  * @n:    Number of bytes to copy.
 472  *
 473  * Context: User context only.  This function may sleep.
 474  *
 475  * Copy data from kernel space to user space.
 476  *
 477  * Returns number of bytes that could not be copied.
 478  * On success, this will be zero.
 479  */
 480 #define copy_to_user(to, from, n)                                       \
 481 ({                                                                      \
 482         void __user *__cu_to;                                           \
 483         const void *__cu_from;                                          \
 484         long __cu_len;                                                  \
 485                                                                         \
 486         might_sleep();                                                  \
 487         __cu_to = (to);                                                 \
 488         __cu_from = (from);                                             \
 489         __cu_len = (n);                                                 \
 490         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 491                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 492                                                  __cu_len);             \
 493         __cu_len;                                                       \
 494 })
 495
 496 #define __invoke_copy_from_user(to, from, n)                            \
 497 ({                                                                      \
 498         register void *__cu_to_r __asm__("$4");                         \
 499         register const void __user *__cu_from_r __asm__("$5");          \
 500         register long __cu_len_r __asm__("$6");                         \
 501                                                                         \
 502         __cu_to_r = (to);                                               \
 503         __cu_from_r = (from);                                           \
 504         __cu_len_r = (n);                                               \
 505         __asm__ __volatile__(                                           \
 506         ".set\tnoreorder\n\t"                                           \
 507         __MODULE_JAL(__copy_user)                                       \
 508         ".set\tnoat\n\t"                                                \
 509         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 510         ".set\tat\n\t"                                                  \
 511         ".set\treorder"                                                 \
 512         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 513         :                                                               \
 514         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 515           "memory");                                                    \
 516         __cu_len_r;                                                     \
 517 })
 518
 519 #define __invoke_copy_from_user_inatomic(to, from, n)                   \
 520 ({                                                                      \
 521         register void *__cu_to_r __asm__("$4");                         \
 522         register const void __user *__cu_from_r __asm__("$5");          \
 523         register long __cu_len_r __asm__("$6");                         \
 524                                                                         \
 525         __cu_to_r = (to);                                               \
 526         __cu_from_r = (from);                                           \
 527         __cu_len_r = (n);                                               \
 528         __asm__ __volatile__(                                           \
 529         ".set\tnoreorder\n\t"                                           \
 530         __MODULE_JAL(__copy_user_inatomic)                              \
 531         ".set\tnoat\n\t"                                                \
 532         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 533         ".set\tat\n\t"                                                  \
 534         ".set\treorder"                                                 \
 535         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 536         :                                                               \
 537         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 538           "memory");                                                    \
 539         __cu_len_r;                                                     \
 540 })
 541
 542 /*
 543  * __copy_from_user: - Copy a block of data from user space, with less checking.
 544  * @to:   Destination address, in kernel space.
 545  * @from: Source address, in user space.
 546  * @n:    Number of bytes to copy.
 547  *
 548  * Context: User context only.  This function may sleep.
 549  *
 550  * Copy data from user space to kernel space.  Caller must check
 551  * the specified block with access_ok() before calling this function.
 552  *
 553  * Returns number of bytes that could not be copied.
 554  * On success, this will be zero.
 555  *
 556  * If some data could not be copied, this function will pad the copied
 557  * data to the requested size using zero bytes.
 558  */
 559 #define __copy_from_user(to, from, n)                                   \
 560 ({                                                                      \
 561         void *__cu_to;                                                  \
 562         const void __user *__cu_from;                                   \
 563         long __cu_len;                                                  \
 564                                                                         \
 565         might_sleep();                                                  \
 566         __cu_to = (to);                                                 \
 567         __cu_from = (from);                                             \
 568         __cu_len = (n);                                                 \
 569         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 570                                            __cu_len);                   \
 571         __cu_len;                                                       \
 572 })
 573
 574 /*
 575  * copy_from_user: - Copy a block of data from user space.
 576  * @to:   Destination address, in kernel space.
 577  * @from: Source address, in user space.
 578  * @n:    Number of bytes to copy.
 579  *
 580  * Context: User context only.  This function may sleep.
 581  *
 582  * Copy data from user space to kernel space.
 583  *
 584  * Returns number of bytes that could not be copied.
 585  * On success, this will be zero.
 586  *
 587  * If some data could not be copied, this function will pad the copied
 588  * data to the requested size using zero bytes.
 589  */
 590 #define copy_from_user(to, from, n)                                     \
 591 ({                                                                      \
 592         void *__cu_to;                                                  \
 593         const void __user *__cu_from;                                   \
 594         long __cu_len;                                                  \
 595                                                                         \
 596         might_sleep();                                                  \
 597         __cu_to = (to);                                                 \
 598         __cu_from = (from);                                             \
 599         __cu_len = (n);                                                 \
 600         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 601                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 602                                                    __cu_len);           \
 603         __cu_len;                                                       \
 604 })
 605
 606 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 607
 608 #define copy_in_user(to, from, n)                                       \
 609 ({                                                                      \
 610         void __user *__cu_to;                                           \
 611         const void __user *__cu_from;                                   \
 612         long __cu_len;                                                  \
 613                                                                         \
 614         might_sleep();                                                  \
 615         __cu_to = (to);                                                 \
 616         __cu_from = (from);                                             \
 617         __cu_len = (n);                                                 \
 618         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 619                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 620                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 621                                                    __cu_len);           \
 622         __cu_len;                                                       \
 623 })
 624
 625 /*
 626  * __clear_user: - Zero a block of memory in user space, with less checking.
 627  * @to:   Destination address, in user space.
 628  * @n:    Number of bytes to zero.
 629  *
 630  * Zero a block of memory in user space.  Caller must check
 631  * the specified block with access_ok() before calling this function.
 632  *
 633  * Returns number of bytes that could not be cleared.
 634  * On success, this will be zero.
 635  */
 636 static inline __kernel_size_t
 637 __clear_user(void __user *addr, __kernel_size_t size)
 638 {
 639         __kernel_size_t res;
 640
 641         might_sleep();
 642         __asm__ __volatile__(
 643                 "move\t$4, %1\n\t"
 644                 "move\t$5, $0\n\t"
 645                 "move\t$6, %2\n\t"
 646                 __MODULE_JAL(__bzero)
 647                 "move\t%0, $6"
 648                 : "=r" (res)
 649                 : "r" (addr), "r" (size)
 650                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 651
 652         return res;
 653 }
 654
 655 #define clear_user(addr,n)                                              \
 656 ({                                                                      \
 657         void __user * __cl_addr = (addr);                               \
 658         unsigned long __cl_size = (n);                                  \
 659         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 660                 ((unsigned long)(__cl_addr)), __cl_size))               \
 661                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 662         __cl_size;                                                      \
 663 })
 664
 665 /*
 666  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 667  * @dst:   Destination address, in kernel space.  This buffer must be at
 668  *         least @count bytes long.
 669  * @src:   Source address, in user space.
 670  * @count: Maximum number of bytes to copy, including the trailing NUL.
 671  *
 672  * Copies a NUL-terminated string from userspace to kernel space.
 673  * Caller must check the specified block with access_ok() before calling
 674  * this function.
 675  *
 676  * On success, returns the length of the string (not including the trailing
 677  * NUL).
 678  *
 679  * If access to userspace fails, returns -EFAULT (some data may have been
 680  * copied).
 681  *
 682  * If @count is smaller than the length of the string, copies @count bytes
 683  * and returns @count.
 684  */
 685 static inline long
 686 __strncpy_from_user(char *__to, const char __user *__from, long __len)
 687 {
 688         long res;
 689
 690         might_sleep();
 691         __asm__ __volatile__(
 692                 "move\t$4, %1\n\t"
 693                 "move\t$5, %2\n\t"
 694                 "move\t$6, %3\n\t"
 695                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 696                 "move\t%0, $2"
 697                 : "=r" (res)
 698                 : "r" (__to), "r" (__from), "r" (__len)
 699                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 700
 701         return res;
 702 }
 703
 704 /*
 705  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 706  * @dst:   Destination address, in kernel space.  This buffer must be at
 707  *         least @count bytes long.
 708  * @src:   Source address, in user space.
 709  * @count: Maximum number of bytes to copy, including the trailing NUL.
 710  *
 711  * Copies a NUL-terminated string from userspace to kernel space.
 712  *
 713  * On success, returns the length of the string (not including the trailing
 714  * NUL).
 715  *
 716  * If access to userspace fails, returns -EFAULT (some data may have been
 717  * copied).
 718  *
 719  * If @count is smaller than the length of the string, copies @count bytes
 720  * and returns @count.
 721  */
 722 static inline long
 723 strncpy_from_user(char *__to, const char __user *__from, long __len)
 724 {
 725         long res;
 726
 727         might_sleep();
 728         __asm__ __volatile__(
 729                 "move\t$4, %1\n\t"
 730                 "move\t$5, %2\n\t"
 731                 "move\t$6, %3\n\t"
 732                 __MODULE_JAL(__strncpy_from_user_asm)
 733                 "move\t%0, $2"
 734                 : "=r" (res)
 735                 : "r" (__to), "r" (__from), "r" (__len)
 736                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 737
 738         return res;
 739 }
 740
 741 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 742 static inline long __strlen_user(const char __user *s)
 743 {
 744         long res;
 745
 746         might_sleep();
 747         __asm__ __volatile__(
 748                 "move\t$4, %1\n\t"
 749                 __MODULE_JAL(__strlen_user_nocheck_asm)
 750                 "move\t%0, $2"
 751                 : "=r" (res)
 752                 : "r" (s)
 753                 : "$2", "$4", __UA_t0, "$31");
 754
 755         return res;
 756 }
 757
 758 /*
 759  * strlen_user: - Get the size of a string in user space.
 760  * @str: The string to measure.
 761  *
 762  * Context: User context only.  This function may sleep.
 763  *
 764  * Get the size of a NUL-terminated string in user space.
 765  *
 766  * Returns the size of the string INCLUDING the terminating NUL.
 767  * On exception, returns 0.
 768  *
 769  * If there is a limit on the length of a valid string, you may wish to
 770  * consider using strnlen_user() instead.
 771  */
 772 static inline long strlen_user(const char __user *s)
 773 {
 774         long res;
 775
 776         might_sleep();
 777         __asm__ __volatile__(
 778                 "move\t$4, %1\n\t"
 779                 __MODULE_JAL(__strlen_user_asm)
 780                 "move\t%0, $2"
 781                 : "=r" (res)
 782                 : "r" (s)
 783                 : "$2", "$4", __UA_t0, "$31");
 784
 785         return res;
 786 }
 787
 788 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 789 static inline long __strnlen_user(const char __user *s, long n)
 790 {
 791         long res;
 792
 793         might_sleep();
 794         __asm__ __volatile__(
 795                 "move\t$4, %1\n\t"
 796                 "move\t$5, %2\n\t"
 797                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 798                 "move\t%0, $2"
 799                 : "=r" (res)
 800                 : "r" (s), "r" (n)
 801                 : "$2", "$4", "$5", __UA_t0, "$31");
 802
 803         return res;
 804 }
 805
 806 /*
 807  * strlen_user: - Get the size of a string in user space.
 808  * @str: The string to measure.
 809  *
 810  * Context: User context only.  This function may sleep.
 811  *
 812  * Get the size of a NUL-terminated string in user space.
 813  *
 814  * Returns the size of the string INCLUDING the terminating NUL.
 815  * On exception, returns 0.
 816  *
 817  * If there is a limit on the length of a valid string, you may wish to
 818  * consider using strnlen_user() instead.
 819  */
 820 static inline long strnlen_user(const char __user *s, long n)
 821 {
 822         long res;
 823
 824         might_sleep();
 825         __asm__ __volatile__(
 826                 "move\t$4, %1\n\t"
 827                 "move\t$5, %2\n\t"
 828                 __MODULE_JAL(__strnlen_user_asm)
 829                 "move\t%0, $2"
 830                 : "=r" (res)
 831                 : "r" (s), "r" (n)
 832                 : "$2", "$4", "$5", __UA_t0, "$31");
 833
 834         return res;
 835 }
 836
 837 struct exception_table_entry
 838 {
 839         unsigned long insn;
 840         unsigned long nextinsn;
 841 };
 842
 843 extern int fixup_exception(struct pt_regs *regs);
 844
 845 #endif /* _ASM_UACCESS_H */