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   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         might_sleep();                                                  \
 217         switch (size) {                                                 \
 218         case 1: __get_user_asm("lb", ptr); break;                       \
 219         case 2: __get_user_asm("lh", ptr); break;                       \
 220         case 4: __get_user_asm("lw", ptr); break;                       \
 221         case 8: __GET_USER_DW(ptr); break;                              \
 222         default: __get_user_unknown(); break;                           \
 223         }                                                               \
 224         (x) = (__typeof__(*(ptr))) __gu_val;                            \
 225         __gu_err;                                                       \
 226 })
 227
 228 #define __get_user_check(x,ptr,size)                                    \
 229 ({                                                                      \
 230         const __typeof__(*(ptr)) __user * __gu_addr = (ptr);            \
 231         __typeof__(*(ptr)) __gu_val = 0;                                \
 232         long __gu_err = -EFAULT;                                        \
 233                                                                         \
 234         if (likely(access_ok(VERIFY_READ,  __gu_addr, size))) {         \
 235                 switch (size) {                                         \
 236                 case 1: __get_user_asm("lb", __gu_addr); break;         \
 237                 case 2: __get_user_asm("lh", __gu_addr); break;         \
 238                 case 4: __get_user_asm("lw", __gu_addr); break;         \
 239                 case 8: __GET_USER_DW(__gu_addr); break;                \
 240                 default: __get_user_unknown(); break;                   \
 241                 }                                                       \
 242         }                                                               \
 243         (x) = (__typeof__(*(ptr))) __gu_val;                            \
 244         __gu_err;                                                       \
 245 })
 246
 247 #define __get_user_asm(insn, addr)                                      \
 248 {                                                                       \
 249         __asm__ __volatile__(                                           \
 250         "1:     " insn "        %1, %3                          \n"     \
 251         "2:                                                     \n"     \
 252         "       .section .fixup,\"ax\"                          \n"     \
 253         "3:     li      %0, %4                                  \n"     \
 254         "       j       2b                                      \n"     \
 255         "       .previous                                       \n"     \
 256         "       .section __ex_table,\"a\"                       \n"     \
 257         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 258         "       .previous                                       \n"     \
 259         : "=r" (__gu_err), "=r" (__gu_val)                              \
 260         : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                     \
 261 }
 262
 263 /*
 264  * Get a long long 64 using 32 bit registers.
 265  */
 266 #define __get_user_asm_ll32(addr)                                       \
 267 {                                                                       \
 268         __asm__ __volatile__(                                           \
 269         "1:     lw      %1, (%3)                                \n"     \
 270         "2:     lw      %D1, 4(%3)                              \n"     \
 271         "       move    %0, $0                                  \n"     \
 272         "3:     .section        .fixup,\"ax\"                   \n"     \
 273         "4:     li      %0, %4                                  \n"     \
 274         "       move    %1, $0                                  \n"     \
 275         "       move    %D1, $0                                 \n"     \
 276         "       j       3b                                      \n"     \
 277         "       .previous                                       \n"     \
 278         "       .section        __ex_table,\"a\"                \n"     \
 279         "       " __UA_ADDR "   1b, 4b                          \n"     \
 280         "       " __UA_ADDR "   2b, 4b                          \n"     \
 281         "       .previous                                       \n"     \
 282         : "=r" (__gu_err), "=&r" (__gu_val)                             \
 283         : "0" (0), "r" (addr), "i" (-EFAULT));                          \
 284 }
 285
 286 extern void __get_user_unknown(void);
 287
 288 /*
 289  * Yuck.  We need two variants, one for 64bit operation and one
 290  * for 32 bit mode and old iron.
 291  */
 292 #ifdef __mips64
 293 #define __PUT_USER_DW(ptr) __put_user_asm("sd", ptr)
 294 #else
 295 #define __PUT_USER_DW(ptr) __put_user_asm_ll32(ptr)
 296 #endif
 297
 298 #define __put_user_nocheck(x,ptr,size)                                  \
 299 ({                                                                      \
 300         __typeof__(*(ptr)) __pu_val;                                    \
 301         long __pu_err = 0;                                              \
 302                                                                         \
 303         might_sleep();                                                  \
 304         __pu_val = (x);                                                 \
 305         switch (size) {                                                 \
 306         case 1: __put_user_asm("sb", ptr); break;                       \
 307         case 2: __put_user_asm("sh", ptr); break;                       \
 308         case 4: __put_user_asm("sw", ptr); break;                       \
 309         case 8: __PUT_USER_DW(ptr); break;                              \
 310         default: __put_user_unknown(); break;                           \
 311         }                                                               \
 312         __pu_err;                                                       \
 313 })
 314
 315 #define __put_user_check(x,ptr,size)                                    \
 316 ({                                                                      \
 317         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 318         __typeof__(*(ptr)) __pu_val = (x);                              \
 319         long __pu_err = -EFAULT;                                        \
 320                                                                         \
 321         if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {        \
 322                 switch (size) {                                         \
 323                 case 1: __put_user_asm("sb", __pu_addr); break;         \
 324                 case 2: __put_user_asm("sh", __pu_addr); break;         \
 325                 case 4: __put_user_asm("sw", __pu_addr); break;         \
 326                 case 8: __PUT_USER_DW(__pu_addr); break;                \
 327                 default: __put_user_unknown(); break;                   \
 328                 }                                                       \
 329         }                                                               \
 330         __pu_err;                                                       \
 331 })
 332
 333 #define __put_user_asm(insn, ptr)                                       \
 334 {                                                                       \
 335         __asm__ __volatile__(                                           \
 336         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 337         "2:                                                     \n"     \
 338         "       .section        .fixup,\"ax\"                   \n"     \
 339         "3:     li      %0, %4                                  \n"     \
 340         "       j       2b                                      \n"     \
 341         "       .previous                                       \n"     \
 342         "       .section        __ex_table,\"a\"                \n"     \
 343         "       " __UA_ADDR "   1b, 3b                          \n"     \
 344         "       .previous                                       \n"     \
 345         : "=r" (__pu_err)                                               \
 346         : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                     \
 347           "i" (-EFAULT));                                               \
 348 }
 349
 350 #define __put_user_asm_ll32(ptr)                                        \
 351 {                                                                       \
 352         __asm__ __volatile__(                                           \
 353         "1:     sw      %2, (%3)        # __put_user_asm_ll32   \n"     \
 354         "2:     sw      %D2, 4(%3)                              \n"     \
 355         "3:                                                     \n"     \
 356         "       .section        .fixup,\"ax\"                   \n"     \
 357         "4:     li      %0, %4                                  \n"     \
 358         "       j       3b                                      \n"     \
 359         "       .previous                                       \n"     \
 360         "       .section        __ex_table,\"a\"                \n"     \
 361         "       " __UA_ADDR "   1b, 4b                          \n"     \
 362         "       " __UA_ADDR "   2b, 4b                          \n"     \
 363         "       .previous"                                              \
 364         : "=r" (__pu_err)                                               \
 365         : "0" (0), "r" (__pu_val), "r" (ptr),                           \
 366           "i" (-EFAULT));                                               \
 367 }
 368
 369 extern void __put_user_unknown(void);
 370
 371 /*
 372  * We're generating jump to subroutines which will be outside the range of
 373  * jump instructions
 374  */
 375 #ifdef MODULE
 376 #define __MODULE_JAL(destination)                                       \
 377         ".set\tnoat\n\t"                                                \
 378         __UA_LA "\t$1, " #destination "\n\t"                            \
 379         "jalr\t$1\n\t"                                                  \
 380         ".set\tat\n\t"
 381 #else
 382 #define __MODULE_JAL(destination)                                       \
 383         "jal\t" #destination "\n\t"
 384 #endif
 385
 386 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 387
 388 #define __invoke_copy_to_user(to,from,n)                                \
 389 ({                                                                      \
 390         register void __user *__cu_to_r __asm__ ("$4");                 \
 391         register const void *__cu_from_r __asm__ ("$5");                \
 392         register long __cu_len_r __asm__ ("$6");                        \
 393                                                                         \
 394         __cu_to_r = (to);                                               \
 395         __cu_from_r = (from);                                           \
 396         __cu_len_r = (n);                                               \
 397         __asm__ __volatile__(                                           \
 398         __MODULE_JAL(__copy_user)                                       \
 399         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 400         :                                                               \
 401         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 402           "memory");                                                    \
 403         __cu_len_r;                                                     \
 404 })
 405
 406 /*
 407  * __copy_to_user: - Copy a block of data into user space, with less checking.
 408  * @to:   Destination address, in user space.
 409  * @from: Source address, in kernel space.
 410  * @n:    Number of bytes to copy.
 411  *
 412  * Context: User context only.  This function may sleep.
 413  *
 414  * Copy data from kernel space to user space.  Caller must check
 415  * the specified block with access_ok() before calling this function.
 416  *
 417  * Returns number of bytes that could not be copied.
 418  * On success, this will be zero.
 419  */
 420 #define __copy_to_user(to,from,n)                                       \
 421 ({                                                                      \
 422         void __user *__cu_to;                                           \
 423         const void *__cu_from;                                          \
 424         long __cu_len;                                                  \
 425                                                                         \
 426         might_sleep();                                                  \
 427         __cu_to = (to);                                                 \
 428         __cu_from = (from);                                             \
 429         __cu_len = (n);                                                 \
 430         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 431         __cu_len;                                                       \
 432 })
 433
 434 #define __copy_to_user_inatomic __copy_to_user
 435 #define __copy_from_user_inatomic __copy_from_user
 436
 437 /*
 438  * copy_to_user: - Copy a block of data into user space.
 439  * @to:   Destination address, in user space.
 440  * @from: Source address, in kernel space.
 441  * @n:    Number of bytes to copy.
 442  *
 443  * Context: User context only.  This function may sleep.
 444  *
 445  * Copy data from kernel space to user space.
 446  *
 447  * Returns number of bytes that could not be copied.
 448  * On success, this will be zero.
 449  */
 450 #define copy_to_user(to,from,n)                                         \
 451 ({                                                                      \
 452         void __user *__cu_to;                                           \
 453         const void *__cu_from;                                          \
 454         long __cu_len;                                                  \
 455                                                                         \
 456         might_sleep();                                                  \
 457         __cu_to = (to);                                                 \
 458         __cu_from = (from);                                             \
 459         __cu_len = (n);                                                 \
 460         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 461                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 462                                                  __cu_len);             \
 463         __cu_len;                                                       \
 464 })
 465
 466 #define __invoke_copy_from_user(to,from,n)                              \
 467 ({                                                                      \
 468         register void *__cu_to_r __asm__ ("$4");                        \
 469         register const void __user *__cu_from_r __asm__ ("$5");         \
 470         register long __cu_len_r __asm__ ("$6");                        \
 471                                                                         \
 472         __cu_to_r = (to);                                               \
 473         __cu_from_r = (from);                                           \
 474         __cu_len_r = (n);                                               \
 475         __asm__ __volatile__(                                           \
 476         ".set\tnoreorder\n\t"                                           \
 477         __MODULE_JAL(__copy_user)                                       \
 478         ".set\tnoat\n\t"                                                \
 479         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 480         ".set\tat\n\t"                                                  \
 481         ".set\treorder"                                                 \
 482         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 483         :                                                               \
 484         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 485           "memory");                                                    \
 486         __cu_len_r;                                                     \
 487 })
 488
 489 /*
 490  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 491  * @from: Source address, in user space.
 492  * @n:    Number of bytes to copy.
 493  *
 494  * Context: User context only.  This function may sleep.
 495  *
 496  * Copy data from user space to kernel space.  Caller must check
 497  * the specified block with access_ok() before calling this function.
 498  *
 499  * Returns number of bytes that could not be copied.
 500  * On success, this will be zero.
 501  *
 502  * If some data could not be copied, this function will pad the copied
 503  * data to the requested size using zero bytes.
 504  */
 505 #define __copy_from_user(to,from,n)                                     \
 506 ({                                                                      \
 507         void *__cu_to;                                                  \
 508         const void __user *__cu_from;                                   \
 509         long __cu_len;                                                  \
 510                                                                         \
 511         might_sleep();                                                  \
 512         __cu_to = (to);                                                 \
 513         __cu_from = (from);                                             \
 514         __cu_len = (n);                                                 \
 515         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 516                                            __cu_len);                   \
 517         __cu_len;                                                       \
 518 })
 519
 520 /*
 521  * copy_from_user: - Copy a block of data from user space.
 522  * @to:   Destination address, in kernel space.
 523  * @from: Source address, in user space.
 524  * @n:    Number of bytes to copy.
 525  *
 526  * Context: User context only.  This function may sleep.
 527  *
 528  * Copy data from user space to kernel space.
 529  *
 530  * Returns number of bytes that could not be copied.
 531  * On success, this will be zero.
 532  *
 533  * If some data could not be copied, this function will pad the copied
 534  * data to the requested size using zero bytes.
 535  */
 536 #define copy_from_user(to,from,n)                                       \
 537 ({                                                                      \
 538         void *__cu_to;                                                  \
 539         const void __user *__cu_from;                                   \
 540         long __cu_len;                                                  \
 541                                                                         \
 542         might_sleep();                                                  \
 543         __cu_to = (to);                                                 \
 544         __cu_from = (from);                                             \
 545         __cu_len = (n);                                                 \
 546         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 547                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 548                                                    __cu_len);           \
 549         __cu_len;                                                       \
 550 })
 551
 552 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 553
 554 #define copy_in_user(to,from,n)                                         \
 555 ({                                                                      \
 556         void __user *__cu_to;                                           \
 557         const void __user *__cu_from;                                   \
 558         long __cu_len;                                                  \
 559                                                                         \
 560         might_sleep();                                                  \
 561         __cu_to = (to);                                                 \
 562         __cu_from = (from);                                             \
 563         __cu_len = (n);                                                 \
 564         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 565                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 566                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 567                                                    __cu_len);           \
 568         __cu_len;                                                       \
 569 })
 570
 571 /*
 572  * __clear_user: - Zero a block of memory in user space, with less checking.
 573  * @to:   Destination address, in user space.
 574  * @n:    Number of bytes to zero.
 575  *
 576  * Zero a block of memory in user space.  Caller must check
 577  * the specified block with access_ok() before calling this function.
 578  *
 579  * Returns number of bytes that could not be cleared.
 580  * On success, this will be zero.
 581  */
 582 static inline __kernel_size_t
 583 __clear_user(void __user *addr, __kernel_size_t size)
 584 {
 585         __kernel_size_t res;
 586
 587         might_sleep();
 588         __asm__ __volatile__(
 589                 "move\t$4, %1\n\t"
 590                 "move\t$5, $0\n\t"
 591                 "move\t$6, %2\n\t"
 592                 __MODULE_JAL(__bzero)
 593                 "move\t%0, $6"
 594                 : "=r" (res)
 595                 : "r" (addr), "r" (size)
 596                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 597
 598         return res;
 599 }
 600
 601 #define clear_user(addr,n)                                              \
 602 ({                                                                      \
 603         void __user * __cl_addr = (addr);                               \
 604         unsigned long __cl_size = (n);                                  \
 605         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 606                 ((unsigned long)(__cl_addr)), __cl_size))               \
 607                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 608         __cl_size;                                                      \
 609 })
 610
 611 /*
 612  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 613  * @dst:   Destination address, in kernel space.  This buffer must be at
 614  *         least @count bytes long.
 615  * @src:   Source address, in user space.
 616  * @count: Maximum number of bytes to copy, including the trailing NUL.
 617  *
 618  * Copies a NUL-terminated string from userspace to kernel space.
 619  * Caller must check the specified block with access_ok() before calling
 620  * this function.
 621  *
 622  * On success, returns the length of the string (not including the trailing
 623  * NUL).
 624  *
 625  * If access to userspace fails, returns -EFAULT (some data may have been
 626  * copied).
 627  *
 628  * If @count is smaller than the length of the string, copies @count bytes
 629  * and returns @count.
 630  */
 631 static inline long
 632 __strncpy_from_user(char *__to, const char __user *__from, long __len)
 633 {
 634         long res;
 635
 636         might_sleep();
 637         __asm__ __volatile__(
 638                 "move\t$4, %1\n\t"
 639                 "move\t$5, %2\n\t"
 640                 "move\t$6, %3\n\t"
 641                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 642                 "move\t%0, $2"
 643                 : "=r" (res)
 644                 : "r" (__to), "r" (__from), "r" (__len)
 645                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 646
 647         return res;
 648 }
 649
 650 /*
 651  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 652  * @dst:   Destination address, in kernel space.  This buffer must be at
 653  *         least @count bytes long.
 654  * @src:   Source address, in user space.
 655  * @count: Maximum number of bytes to copy, including the trailing NUL.
 656  *
 657  * Copies a NUL-terminated string from userspace to kernel space.
 658  *
 659  * On success, returns the length of the string (not including the trailing
 660  * NUL).
 661  *
 662  * If access to userspace fails, returns -EFAULT (some data may have been
 663  * copied).
 664  *
 665  * If @count is smaller than the length of the string, copies @count bytes
 666  * and returns @count.
 667  */
 668 static inline long
 669 strncpy_from_user(char *__to, const char __user *__from, long __len)
 670 {
 671         long res;
 672
 673         might_sleep();
 674         __asm__ __volatile__(
 675                 "move\t$4, %1\n\t"
 676                 "move\t$5, %2\n\t"
 677                 "move\t$6, %3\n\t"
 678                 __MODULE_JAL(__strncpy_from_user_asm)
 679                 "move\t%0, $2"
 680                 : "=r" (res)
 681                 : "r" (__to), "r" (__from), "r" (__len)
 682                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 683
 684         return res;
 685 }
 686
 687 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 688 static inline long __strlen_user(const char __user *s)
 689 {
 690         long res;
 691
 692         might_sleep();
 693         __asm__ __volatile__(
 694                 "move\t$4, %1\n\t"
 695                 __MODULE_JAL(__strlen_user_nocheck_asm)
 696                 "move\t%0, $2"
 697                 : "=r" (res)
 698                 : "r" (s)
 699                 : "$2", "$4", __UA_t0, "$31");
 700
 701         return res;
 702 }
 703
 704 /*
 705  * strlen_user: - Get the size of a string in user space.
 706  * @str: The string to measure.
 707  *
 708  * Context: User context only.  This function may sleep.
 709  *
 710  * Get the size of a NUL-terminated string in user space.
 711  *
 712  * Returns the size of the string INCLUDING the terminating NUL.
 713  * On exception, returns 0.
 714  *
 715  * If there is a limit on the length of a valid string, you may wish to
 716  * consider using strnlen_user() instead.
 717  */
 718 static inline long strlen_user(const char __user *s)
 719 {
 720         long res;
 721
 722         might_sleep();
 723         __asm__ __volatile__(
 724                 "move\t$4, %1\n\t"
 725                 __MODULE_JAL(__strlen_user_asm)
 726                 "move\t%0, $2"
 727                 : "=r" (res)
 728                 : "r" (s)
 729                 : "$2", "$4", __UA_t0, "$31");
 730
 731         return res;
 732 }
 733
 734 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 735 static inline long __strnlen_user(const char __user *s, long n)
 736 {
 737         long res;
 738
 739         might_sleep();
 740         __asm__ __volatile__(
 741                 "move\t$4, %1\n\t"
 742                 "move\t$5, %2\n\t"
 743                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 744                 "move\t%0, $2"
 745                 : "=r" (res)
 746                 : "r" (s), "r" (n)
 747                 : "$2", "$4", "$5", __UA_t0, "$31");
 748
 749         return res;
 750 }
 751
 752 /*
 753  * strlen_user: - Get the size of a string in user space.
 754  * @str: The string to measure.
 755  *
 756  * Context: User context only.  This function may sleep.
 757  *
 758  * Get the size of a NUL-terminated string in user space.
 759  *
 760  * Returns the size of the string INCLUDING the terminating NUL.
 761  * On exception, returns 0.
 762  *
 763  * If there is a limit on the length of a valid string, you may wish to
 764  * consider using strnlen_user() instead.
 765  */
 766 static inline long strnlen_user(const char __user *s, long n)
 767 {
 768         long res;
 769
 770         might_sleep();
 771         __asm__ __volatile__(
 772                 "move\t$4, %1\n\t"
 773                 "move\t$5, %2\n\t"
 774                 __MODULE_JAL(__strnlen_user_asm)
 775                 "move\t%0, $2"
 776                 : "=r" (res)
 777                 : "r" (s), "r" (n)
 778                 : "$2", "$4", "$5", __UA_t0, "$31");
 779
 780         return res;
 781 }
 782
 783 struct exception_table_entry
 784 {
 785         unsigned long insn;
 786         unsigned long nextinsn;
 787 };
 788
 789 extern int fixup_exception(struct pt_regs *regs);
 790
 791 #endif /* _ASM_UACCESS_H */