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 __mips64
 206 #define __GET_USER_DW(ptr) __get_user_asm("ld", ptr)
 207 #else
 208 #define __GET_USER_DW(ptr) __get_user_asm_ll32(ptr)
 209 #endif
 210
 211 #define __get_user_nocheck(x,ptr,size)                                  \
 212 ({                                                                      \
 213         __typeof(*(ptr)) __gu_val =  (__typeof(*(ptr))) 0;              \
 214         long __gu_err = 0;                                              \
 215                                                                         \
 216         switch (size) {                                                 \
 217         case 1: __get_user_asm("lb", ptr); break;                       \
 218         case 2: __get_user_asm("lh", ptr); break;                       \
 219         case 4: __get_user_asm("lw", ptr); break;                       \
 220         case 8: __GET_USER_DW(ptr); break;                              \
 221         default: __get_user_unknown(); break;                           \
 222         }                                                               \
 223         (x) = (__typeof__(*(ptr))) __gu_val;                            \
 224         __gu_err;                                                       \
 225 })
 226
 227 #define __get_user_check(x,ptr,size)                                    \
 228 ({                                                                      \
 229         const __typeof__(*(ptr)) __user * __gu_addr = (ptr);            \
 230         __typeof__(*(ptr)) __gu_val = 0;                                \
 231         long __gu_err = -EFAULT;                                        \
 232                                                                         \
 233         if (likely(access_ok(VERIFY_READ,  __gu_addr, size))) {         \
 234                 switch (size) {                                         \
 235                 case 1: __get_user_asm("lb", __gu_addr); break;         \
 236                 case 2: __get_user_asm("lh", __gu_addr); break;         \
 237                 case 4: __get_user_asm("lw", __gu_addr); break;         \
 238                 case 8: __GET_USER_DW(__gu_addr); break;                \
 239                 default: __get_user_unknown(); break;                   \
 240                 }                                                       \
 241         }                                                               \
 242         (x) = (__typeof__(*(ptr))) __gu_val;                            \
 243         __gu_err;                                                       \
 244 })
 245
 246 #define __get_user_asm(insn, addr)                                      \
 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_val)                              \
 259         : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                     \
 260 }
 261
 262 /*
 263  * Get a long long 64 using 32 bit registers.
 264  */
 265 #define __get_user_asm_ll32(addr)                                       \
 266 {                                                                       \
 267         __asm__ __volatile__(                                           \
 268         "1:     lw      %1, (%3)                                \n"     \
 269         "2:     lw      %D1, 4(%3)                              \n"     \
 270         "       move    %0, $0                                  \n"     \
 271         "3:     .section        .fixup,\"ax\"                   \n"     \
 272         "4:     li      %0, %4                                  \n"     \
 273         "       move    %1, $0                                  \n"     \
 274         "       move    %D1, $0                                 \n"     \
 275         "       j       3b                                      \n"     \
 276         "       .previous                                       \n"     \
 277         "       .section        __ex_table,\"a\"                \n"     \
 278         "       " __UA_ADDR "   1b, 4b                          \n"     \
 279         "       " __UA_ADDR "   2b, 4b                          \n"     \
 280         "       .previous                                       \n"     \
 281         : "=r" (__gu_err), "=&r" (__gu_val)                             \
 282         : "0" (0), "r" (addr), "i" (-EFAULT));                          \
 283 }
 284
 285 extern void __get_user_unknown(void);
 286
 287 /*
 288  * Yuck.  We need two variants, one for 64bit operation and one
 289  * for 32 bit mode and old iron.
 290  */
 291 #ifdef __mips64
 292 #define __PUT_USER_DW(ptr) __put_user_asm("sd", ptr)
 293 #else
 294 #define __PUT_USER_DW(ptr) __put_user_asm_ll32(ptr)
 295 #endif
 296
 297 #define __put_user_nocheck(x,ptr,size)                                  \
 298 ({                                                                      \
 299         __typeof__(*(ptr)) __pu_val;                                    \
 300         long __pu_err = 0;                                              \
 301                                                                         \
 302         __pu_val = (x);                                                 \
 303         switch (size) {                                                 \
 304         case 1: __put_user_asm("sb", ptr); break;                       \
 305         case 2: __put_user_asm("sh", ptr); break;                       \
 306         case 4: __put_user_asm("sw", ptr); break;                       \
 307         case 8: __PUT_USER_DW(ptr); break;                              \
 308         default: __put_user_unknown(); break;                           \
 309         }                                                               \
 310         __pu_err;                                                       \
 311 })
 312
 313 #define __put_user_check(x,ptr,size)                                    \
 314 ({                                                                      \
 315         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 316         __typeof__(*(ptr)) __pu_val = (x);                              \
 317         long __pu_err = -EFAULT;                                        \
 318                                                                         \
 319         if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {        \
 320                 switch (size) {                                         \
 321                 case 1: __put_user_asm("sb", __pu_addr); break;         \
 322                 case 2: __put_user_asm("sh", __pu_addr); break;         \
 323                 case 4: __put_user_asm("sw", __pu_addr); break;         \
 324                 case 8: __PUT_USER_DW(__pu_addr); break;                \
 325                 default: __put_user_unknown(); break;                   \
 326                 }                                                       \
 327         }                                                               \
 328         __pu_err;                                                       \
 329 })
 330
 331 #define __put_user_asm(insn, ptr)                                       \
 332 {                                                                       \
 333         __asm__ __volatile__(                                           \
 334         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 335         "2:                                                     \n"     \
 336         "       .section        .fixup,\"ax\"                   \n"     \
 337         "3:     li      %0, %4                                  \n"     \
 338         "       j       2b                                      \n"     \
 339         "       .previous                                       \n"     \
 340         "       .section        __ex_table,\"a\"                \n"     \
 341         "       " __UA_ADDR "   1b, 3b                          \n"     \
 342         "       .previous                                       \n"     \
 343         : "=r" (__pu_err)                                               \
 344         : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                     \
 345           "i" (-EFAULT));                                               \
 346 }
 347
 348 #define __put_user_asm_ll32(ptr)                                        \
 349 {                                                                       \
 350         __asm__ __volatile__(                                           \
 351         "1:     sw      %2, (%3)        # __put_user_asm_ll32   \n"     \
 352         "2:     sw      %D2, 4(%3)                              \n"     \
 353         "3:                                                     \n"     \
 354         "       .section        .fixup,\"ax\"                   \n"     \
 355         "4:     li      %0, %4                                  \n"     \
 356         "       j       3b                                      \n"     \
 357         "       .previous                                       \n"     \
 358         "       .section        __ex_table,\"a\"                \n"     \
 359         "       " __UA_ADDR "   1b, 4b                          \n"     \
 360         "       " __UA_ADDR "   2b, 4b                          \n"     \
 361         "       .previous"                                              \
 362         : "=r" (__pu_err)                                               \
 363         : "0" (0), "r" (__pu_val), "r" (ptr),                           \
 364           "i" (-EFAULT));                                               \
 365 }
 366
 367 extern void __put_user_unknown(void);
 368
 369 /*
 370  * We're generating jump to subroutines which will be outside the range of
 371  * jump instructions
 372  */
 373 #ifdef MODULE
 374 #define __MODULE_JAL(destination)                                       \
 375         ".set\tnoat\n\t"                                                \
 376         __UA_LA "\t$1, " #destination "\n\t"                            \
 377         "jalr\t$1\n\t"                                                  \
 378         ".set\tat\n\t"
 379 #else
 380 #define __MODULE_JAL(destination)                                       \
 381         "jal\t" #destination "\n\t"
 382 #endif
 383
 384 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 385
 386 #define __invoke_copy_to_user(to,from,n)                                \
 387 ({                                                                      \
 388         register void __user *__cu_to_r __asm__ ("$4");                 \
 389         register const void *__cu_from_r __asm__ ("$5");                \
 390         register long __cu_len_r __asm__ ("$6");                        \
 391                                                                         \
 392         __cu_to_r = (to);                                               \
 393         __cu_from_r = (from);                                           \
 394         __cu_len_r = (n);                                               \
 395         __asm__ __volatile__(                                           \
 396         __MODULE_JAL(__copy_user)                                       \
 397         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 398         :                                                               \
 399         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 400           "memory");                                                    \
 401         __cu_len_r;                                                     \
 402 })
 403
 404 /*
 405  * __copy_to_user: - Copy a block of data into user space, with less checking.
 406  * @to:   Destination address, in user space.
 407  * @from: Source address, in kernel space.
 408  * @n:    Number of bytes to copy.
 409  *
 410  * Context: User context only.  This function may sleep.
 411  *
 412  * Copy data from kernel space to user space.  Caller must check
 413  * the specified block with access_ok() before calling this function.
 414  *
 415  * Returns number of bytes that could not be copied.
 416  * On success, this will be zero.
 417  */
 418 #define __copy_to_user(to,from,n)                                       \
 419 ({                                                                      \
 420         void __user *__cu_to;                                           \
 421         const void *__cu_from;                                          \
 422         long __cu_len;                                                  \
 423                                                                         \
 424         might_sleep();                                                  \
 425         __cu_to = (to);                                                 \
 426         __cu_from = (from);                                             \
 427         __cu_len = (n);                                                 \
 428         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 429         __cu_len;                                                       \
 430 })
 431
 432 #define __copy_to_user_inatomic __copy_to_user
 433 #define __copy_from_user_inatomic __copy_from_user
 434
 435 /*
 436  * copy_to_user: - Copy a block of data into user space.
 437  * @to:   Destination address, in user space.
 438  * @from: Source address, in kernel space.
 439  * @n:    Number of bytes to copy.
 440  *
 441  * Context: User context only.  This function may sleep.
 442  *
 443  * Copy data from kernel space to user space.
 444  *
 445  * Returns number of bytes that could not be copied.
 446  * On success, this will be zero.
 447  */
 448 #define copy_to_user(to,from,n)                                         \
 449 ({                                                                      \
 450         void __user *__cu_to;                                           \
 451         const void *__cu_from;                                          \
 452         long __cu_len;                                                  \
 453                                                                         \
 454         might_sleep();                                                  \
 455         __cu_to = (to);                                                 \
 456         __cu_from = (from);                                             \
 457         __cu_len = (n);                                                 \
 458         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 459                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 460                                                  __cu_len);             \
 461         __cu_len;                                                       \
 462 })
 463
 464 #define __invoke_copy_from_user(to,from,n)                              \
 465 ({                                                                      \
 466         register void *__cu_to_r __asm__ ("$4");                        \
 467         register const void __user *__cu_from_r __asm__ ("$5");         \
 468         register long __cu_len_r __asm__ ("$6");                        \
 469                                                                         \
 470         __cu_to_r = (to);                                               \
 471         __cu_from_r = (from);                                           \
 472         __cu_len_r = (n);                                               \
 473         __asm__ __volatile__(                                           \
 474         ".set\tnoreorder\n\t"                                           \
 475         __MODULE_JAL(__copy_user)                                       \
 476         ".set\tnoat\n\t"                                                \
 477         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 478         ".set\tat\n\t"                                                  \
 479         ".set\treorder"                                                 \
 480         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 481         :                                                               \
 482         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 483           "memory");                                                    \
 484         __cu_len_r;                                                     \
 485 })
 486
 487 /*
 488  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 489  * @from: Source address, in user space.
 490  * @n:    Number of bytes to copy.
 491  *
 492  * Context: User context only.  This function may sleep.
 493  *
 494  * Copy data from user space to kernel space.  Caller must check
 495  * the specified block with access_ok() before calling this function.
 496  *
 497  * Returns number of bytes that could not be copied.
 498  * On success, this will be zero.
 499  *
 500  * If some data could not be copied, this function will pad the copied
 501  * data to the requested size using zero bytes.
 502  */
 503 #define __copy_from_user(to,from,n)                                     \
 504 ({                                                                      \
 505         void *__cu_to;                                                  \
 506         const void __user *__cu_from;                                   \
 507         long __cu_len;                                                  \
 508                                                                         \
 509         might_sleep();                                                  \
 510         __cu_to = (to);                                                 \
 511         __cu_from = (from);                                             \
 512         __cu_len = (n);                                                 \
 513         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 514                                            __cu_len);                   \
 515         __cu_len;                                                       \
 516 })
 517
 518 /*
 519  * copy_from_user: - Copy a block of data from user space.
 520  * @to:   Destination address, in kernel space.
 521  * @from: Source address, in user space.
 522  * @n:    Number of bytes to copy.
 523  *
 524  * Context: User context only.  This function may sleep.
 525  *
 526  * Copy data from user space to kernel space.
 527  *
 528  * Returns number of bytes that could not be copied.
 529  * On success, this will be zero.
 530  *
 531  * If some data could not be copied, this function will pad the copied
 532  * data to the requested size using zero bytes.
 533  */
 534 #define copy_from_user(to,from,n)                                       \
 535 ({                                                                      \
 536         void *__cu_to;                                                  \
 537         const void __user *__cu_from;                                   \
 538         long __cu_len;                                                  \
 539                                                                         \
 540         might_sleep();                                                  \
 541         __cu_to = (to);                                                 \
 542         __cu_from = (from);                                             \
 543         __cu_len = (n);                                                 \
 544         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 545                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 546                                                    __cu_len);           \
 547         __cu_len;                                                       \
 548 })
 549
 550 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 551
 552 #define copy_in_user(to,from,n)                                         \
 553 ({                                                                      \
 554         void __user *__cu_to;                                           \
 555         const void __user *__cu_from;                                   \
 556         long __cu_len;                                                  \
 557                                                                         \
 558         might_sleep();                                                  \
 559         __cu_to = (to);                                                 \
 560         __cu_from = (from);                                             \
 561         __cu_len = (n);                                                 \
 562         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 563                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 564                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 565                                                    __cu_len);           \
 566         __cu_len;                                                       \
 567 })
 568
 569 /*
 570  * __clear_user: - Zero a block of memory in user space, with less checking.
 571  * @to:   Destination address, in user space.
 572  * @n:    Number of bytes to zero.
 573  *
 574  * Zero a block of memory in user space.  Caller must check
 575  * the specified block with access_ok() before calling this function.
 576  *
 577  * Returns number of bytes that could not be cleared.
 578  * On success, this will be zero.
 579  */
 580 static inline __kernel_size_t
 581 __clear_user(void __user *addr, __kernel_size_t size)
 582 {
 583         __kernel_size_t res;
 584
 585         might_sleep();
 586         __asm__ __volatile__(
 587                 "move\t$4, %1\n\t"
 588                 "move\t$5, $0\n\t"
 589                 "move\t$6, %2\n\t"
 590                 __MODULE_JAL(__bzero)
 591                 "move\t%0, $6"
 592                 : "=r" (res)
 593                 : "r" (addr), "r" (size)
 594                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 595
 596         return res;
 597 }
 598
 599 #define clear_user(addr,n)                                              \
 600 ({                                                                      \
 601         void __user * __cl_addr = (addr);                               \
 602         unsigned long __cl_size = (n);                                  \
 603         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 604                 ((unsigned long)(__cl_addr)), __cl_size))               \
 605                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 606         __cl_size;                                                      \
 607 })
 608
 609 /*
 610  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 611  * @dst:   Destination address, in kernel space.  This buffer must be at
 612  *         least @count bytes long.
 613  * @src:   Source address, in user space.
 614  * @count: Maximum number of bytes to copy, including the trailing NUL.
 615  *
 616  * Copies a NUL-terminated string from userspace to kernel space.
 617  * Caller must check the specified block with access_ok() before calling
 618  * this function.
 619  *
 620  * On success, returns the length of the string (not including the trailing
 621  * NUL).
 622  *
 623  * If access to userspace fails, returns -EFAULT (some data may have been
 624  * copied).
 625  *
 626  * If @count is smaller than the length of the string, copies @count bytes
 627  * and returns @count.
 628  */
 629 static inline long
 630 __strncpy_from_user(char *__to, const char __user *__from, long __len)
 631 {
 632         long res;
 633
 634         might_sleep();
 635         __asm__ __volatile__(
 636                 "move\t$4, %1\n\t"
 637                 "move\t$5, %2\n\t"
 638                 "move\t$6, %3\n\t"
 639                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 640                 "move\t%0, $2"
 641                 : "=r" (res)
 642                 : "r" (__to), "r" (__from), "r" (__len)
 643                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 644
 645         return res;
 646 }
 647
 648 /*
 649  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 650  * @dst:   Destination address, in kernel space.  This buffer must be at
 651  *         least @count bytes long.
 652  * @src:   Source address, in user space.
 653  * @count: Maximum number of bytes to copy, including the trailing NUL.
 654  *
 655  * Copies a NUL-terminated string from userspace to kernel space.
 656  *
 657  * On success, returns the length of the string (not including the trailing
 658  * NUL).
 659  *
 660  * If access to userspace fails, returns -EFAULT (some data may have been
 661  * copied).
 662  *
 663  * If @count is smaller than the length of the string, copies @count bytes
 664  * and returns @count.
 665  */
 666 static inline long
 667 strncpy_from_user(char *__to, const char __user *__from, long __len)
 668 {
 669         long res;
 670
 671         might_sleep();
 672         __asm__ __volatile__(
 673                 "move\t$4, %1\n\t"
 674                 "move\t$5, %2\n\t"
 675                 "move\t$6, %3\n\t"
 676                 __MODULE_JAL(__strncpy_from_user_asm)
 677                 "move\t%0, $2"
 678                 : "=r" (res)
 679                 : "r" (__to), "r" (__from), "r" (__len)
 680                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 681
 682         return res;
 683 }
 684
 685 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 686 static inline long __strlen_user(const char __user *s)
 687 {
 688         long res;
 689
 690         might_sleep();
 691         __asm__ __volatile__(
 692                 "move\t$4, %1\n\t"
 693                 __MODULE_JAL(__strlen_user_nocheck_asm)
 694                 "move\t%0, $2"
 695                 : "=r" (res)
 696                 : "r" (s)
 697                 : "$2", "$4", __UA_t0, "$31");
 698
 699         return res;
 700 }
 701
 702 /*
 703  * strlen_user: - Get the size of a string in user space.
 704  * @str: The string to measure.
 705  *
 706  * Context: User context only.  This function may sleep.
 707  *
 708  * Get the size of a NUL-terminated string in user space.
 709  *
 710  * Returns the size of the string INCLUDING the terminating NUL.
 711  * On exception, returns 0.
 712  *
 713  * If there is a limit on the length of a valid string, you may wish to
 714  * consider using strnlen_user() instead.
 715  */
 716 static inline long strlen_user(const char __user *s)
 717 {
 718         long res;
 719
 720         might_sleep();
 721         __asm__ __volatile__(
 722                 "move\t$4, %1\n\t"
 723                 __MODULE_JAL(__strlen_user_asm)
 724                 "move\t%0, $2"
 725                 : "=r" (res)
 726                 : "r" (s)
 727                 : "$2", "$4", __UA_t0, "$31");
 728
 729         return res;
 730 }
 731
 732 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 733 static inline long __strnlen_user(const char __user *s, long n)
 734 {
 735         long res;
 736
 737         might_sleep();
 738         __asm__ __volatile__(
 739                 "move\t$4, %1\n\t"
 740                 "move\t$5, %2\n\t"
 741                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 742                 "move\t%0, $2"
 743                 : "=r" (res)
 744                 : "r" (s), "r" (n)
 745                 : "$2", "$4", "$5", __UA_t0, "$31");
 746
 747         return res;
 748 }
 749
 750 /*
 751  * strlen_user: - Get the size of a string in user space.
 752  * @str: The string to measure.
 753  *
 754  * Context: User context only.  This function may sleep.
 755  *
 756  * Get the size of a NUL-terminated string in user space.
 757  *
 758  * Returns the size of the string INCLUDING the terminating NUL.
 759  * On exception, returns 0.
 760  *
 761  * If there is a limit on the length of a valid string, you may wish to
 762  * consider using strnlen_user() instead.
 763  */
 764 static inline long strnlen_user(const char __user *s, long n)
 765 {
 766         long res;
 767
 768         might_sleep();
 769         __asm__ __volatile__(
 770                 "move\t$4, %1\n\t"
 771                 "move\t$5, %2\n\t"
 772                 __MODULE_JAL(__strnlen_user_asm)
 773                 "move\t%0, $2"
 774                 : "=r" (res)
 775                 : "r" (s), "r" (n)
 776                 : "$2", "$4", "$5", __UA_t0, "$31");
 777
 778         return res;
 779 }
 780
 781 struct exception_table_entry
 782 {
 783         unsigned long insn;
 784         unsigned long nextinsn;
 785 };
 786
 787 extern int fixup_exception(struct pt_regs *regs);
 788
 789 #endif /* _ASM_UACCESS_H */