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