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/compiler.h>
  14 #include <linux/errno.h>
  15 #include <linux/sched.h>
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24 #ifdef CONFIG_MIPS32
  25
  26 #define __UA_LIMIT      0x80000000UL
  27
  28 #define __UA_ADDR       ".word"
  29 #define __UA_LA         "la"
  30 #define __UA_ADDU       "addu"
  31 #define __UA_t0         "$8"
  32 #define __UA_t1         "$9"
  33
  34 #endif /* CONFIG_MIPS32 */
  35
  36 #ifdef CONFIG_MIPS64
  37
  38 #define __UA_LIMIT      (- TASK_SIZE)
  39
  40 #define __UA_ADDR       ".dword"
  41 #define __UA_LA         "dla"
  42 #define __UA_ADDU       "daddu"
  43 #define __UA_t0         "$12"
  44 #define __UA_t1         "$13"
  45
  46 #endif /* CONFIG_MIPS64 */
  47
  48 /*
  49  * USER_DS is a bitmask that has the bits set that may not be set in a valid
  50  * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
  51  * the arithmetic we're doing only works if the limit is a power of two, so
  52  * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
  53  * address in this range it's the process's problem, not ours :-)
  54  */
  55
  56 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  57 #define USER_DS         ((mm_segment_t) { __UA_LIMIT })
  58
  59 #define VERIFY_READ    0
  60 #define VERIFY_WRITE   1
  61
  62 #define get_ds()        (KERNEL_DS)
  63 #define get_fs()        (current->thread.current_ds)
  64 #define set_fs(x)       (current->thread.current_ds = (x))
  65
  66 #define segment_eq(a,b) ((a).seg == (b).seg)
  67
  68
  69 /*
  70  * Is a address valid? This does a straighforward calculation rather
  71  * than tests.
  72  *
  73  * Address valid if:
  74  *  - "addr" doesn't have any high-bits set
  75  *  - AND "size" doesn't have any high-bits set
  76  *  - AND "addr+size" doesn't have any high-bits set
  77  *  - OR we are in kernel mode.
  78  *
  79  * __ua_size() is a trick to avoid runtime checking of positive constant
  80  * sizes; for those we already know at compile time that the size is ok.
  81  */
  82 #define __ua_size(size)                                                 \
  83         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  84
  85 /*
  86  * access_ok: - Checks if a user space pointer is valid
  87  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  88  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  89  *        to write to a block, it is always safe to read from it.
  90  * @addr: User space pointer to start of block to check
  91  * @size: Size of block to check
  92  *
  93  * Context: User context only.  This function may sleep.
  94  *
  95  * Checks if a pointer to a block of memory in user space is valid.
  96  *
  97  * Returns true (nonzero) if the memory block may be valid, false (zero)
  98  * if it is definitely invalid.
  99  *
 100  * Note that, depending on architecture, this function probably just
 101  * checks that the pointer is in the user space range - after calling
 102  * this function, memory access functions may still return -EFAULT.
 103  */
 104
 105 #define __access_mask get_fs().seg
 106
 107 #define __access_ok(addr, size, mask)                                   \
 108         (((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)
 109
 110 #define access_ok(type, addr, size)                                     \
 111         likely(__access_ok((unsigned long)(addr), (size),__access_mask))
 112
 113 /*
 114  * verify_area: - Obsolete, use access_ok()
 115  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
 116  * @addr: User space pointer to start of block to check
 117  * @size: Size of block to check
 118  *
 119  * Context: User context only.  This function may sleep.
 120  *
 121  * This function has been replaced by access_ok().
 122  *
 123  * Checks if a pointer to a block of memory in user space is valid.
 124  *
 125  * Returns zero if the memory block may be valid, -EFAULT
 126  * if it is definitely invalid.
 127  *
 128  * See access_ok() for more details.
 129  */
 130 static inline int verify_area(int type, const void * addr, unsigned long size)
 131 {
 132         return access_ok(type, addr, size) ? 0 : -EFAULT;
 133 }
 134
 135 /*
 136  * put_user: - Write a simple value into user space.
 137  * @x:   Value to copy to user space.
 138  * @ptr: Destination address, in user space.
 139  *
 140  * Context: User context only.  This function may sleep.
 141  *
 142  * This macro copies a single simple value from kernel space to user
 143  * space.  It supports simple types like char and int, but not larger
 144  * data types like structures or arrays.
 145  *
 146  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 147  * to the result of dereferencing @ptr.
 148  *
 149  * Returns zero on success, or -EFAULT on error.
 150  */
 151 #define put_user(x,ptr) \
 152         __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 153
 154 /*
 155  * get_user: - Get a simple variable from user space.
 156  * @x:   Variable to store result.
 157  * @ptr: Source address, in user space.
 158  *
 159  * Context: User context only.  This function may sleep.
 160  *
 161  * This macro copies a single simple variable from user space to kernel
 162  * space.  It supports simple types like char and int, but not larger
 163  * data types like structures or arrays.
 164  *
 165  * @ptr must have pointer-to-simple-variable type, and the result of
 166  * dereferencing @ptr must be assignable to @x without a cast.
 167  *
 168  * Returns zero on success, or -EFAULT on error.
 169  * On error, the variable @x is set to zero.
 170  */
 171 #define get_user(x,ptr) \
 172         __get_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 173
 174 /*
 175  * __put_user: - Write a simple value into user space, with less checking.
 176  * @x:   Value to copy to user space.
 177  * @ptr: Destination address, in user space.
 178  *
 179  * Context: User context only.  This function may sleep.
 180  *
 181  * This macro copies a single simple value from kernel space to user
 182  * space.  It supports simple types like char and int, but not larger
 183  * data types like structures or arrays.
 184  *
 185  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 186  * to the result of dereferencing @ptr.
 187  *
 188  * Caller must check the pointer with access_ok() before calling this
 189  * function.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  */
 193 #define __put_user(x,ptr) \
 194         __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 195
 196 /*
 197  * __get_user: - Get a simple variable from user space, with less checking.
 198  * @x:   Variable to store result.
 199  * @ptr: Source address, in user space.
 200  *
 201  * Context: User context only.  This function may sleep.
 202  *
 203  * This macro copies a single simple variable from user space to kernel
 204  * space.  It supports simple types like char and int, but not larger
 205  * data types like structures or arrays.
 206  *
 207  * @ptr must have pointer-to-simple-variable type, and the result of
 208  * dereferencing @ptr must be assignable to @x without a cast.
 209  *
 210  * Caller must check the pointer with access_ok() before calling this
 211  * function.
 212  *
 213  * Returns zero on success, or -EFAULT on error.
 214  * On error, the variable @x is set to zero.
 215  */
 216 #define __get_user(x,ptr) \
 217         __get_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 218
 219 struct __large_struct { unsigned long buf[100]; };
 220 #define __m(x) (*(struct __large_struct *)(x))
 221
 222 /*
 223  * Yuck.  We need two variants, one for 64bit operation and one
 224  * for 32 bit mode and old iron.
 225  */
 226 #ifdef __mips64
 227 #define __GET_USER_DW(__gu_err) __get_user_asm("ld", __gu_err)
 228 #else
 229 #define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err)
 230 #endif
 231
 232 #define __get_user_nocheck(x,ptr,size)                                  \
 233 ({                                                                      \
 234         long __gu_err = 0;                                              \
 235         __typeof(*(ptr)) __gu_val = 0;                                  \
 236         long __gu_addr;                                                 \
 237         __gu_addr = (long) (ptr);                                       \
 238         switch (size) {                                                 \
 239         case 1: __get_user_asm("lb", __gu_err); break;                  \
 240         case 2: __get_user_asm("lh", __gu_err); break;                  \
 241         case 4: __get_user_asm("lw", __gu_err); break;                  \
 242         case 8: __GET_USER_DW(__gu_err); break;                         \
 243         default: __get_user_unknown(); break;                           \
 244         }                                                               \
 245          x = (__typeof__(*(ptr))) __gu_val;                             \
 246         __gu_err;                                                       \
 247 })
 248
 249 #define __get_user_check(x,ptr,size)                                    \
 250 ({                                                                      \
 251         __typeof__(*(ptr)) __gu_val = 0;                                \
 252         long __gu_addr = (long) (ptr);                                  \
 253         long __gu_err;                                                  \
 254                                                                         \
 255         __gu_err = verify_area(VERIFY_READ, (void *) __gu_addr, size);  \
 256                                                                         \
 257         if (likely(!__gu_err)) {                                        \
 258                 switch (size) {                                         \
 259                 case 1: __get_user_asm("lb", __gu_err); break;          \
 260                 case 2: __get_user_asm("lh", __gu_err); break;          \
 261                 case 4: __get_user_asm("lw", __gu_err); break;          \
 262                 case 8: __GET_USER_DW(__gu_err); break;                 \
 263                 default: __get_user_unknown(); break;                   \
 264                 }                                                       \
 265         }                                                               \
 266         x = (__typeof__(*(ptr))) __gu_val;                              \
 267          __gu_err;                                                      \
 268 })
 269
 270 #define __get_user_asm(insn,__gu_err)                                   \
 271 ({                                                                      \
 272         __asm__ __volatile__(                                           \
 273         "1:     " insn "        %1, %3                          \n"     \
 274         "2:                                                     \n"     \
 275         "       .section .fixup,\"ax\"                          \n"     \
 276         "3:     li      %0, %4                                  \n"     \
 277         "       j       2b                                      \n"     \
 278         "       .previous                                       \n"     \
 279         "       .section __ex_table,\"a\"                       \n"     \
 280         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 281         "       .previous                                       \n"     \
 282         : "=r" (__gu_err), "=r" (__gu_val)                              \
 283         : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT));         \
 284 })
 285
 286 /*
 287  * Get a long long 64 using 32 bit registers.
 288  */
 289 #define __get_user_asm_ll32(__gu_err)                                   \
 290 ({                                                                      \
 291         __asm__ __volatile__(                                           \
 292         "1:     lw      %1, %3                                  \n"     \
 293         "2:     lw      %D1, %4                                 \n"     \
 294         "       move    %0, $0                                  \n"     \
 295         "3:     .section        .fixup,\"ax\"                   \n"     \
 296         "4:     li      %0, %5                                  \n"     \
 297         "       move    %1, $0                                  \n"     \
 298         "       move    %D1, $0                                 \n"     \
 299         "       j       3b                                      \n"     \
 300         "       .previous                                       \n"     \
 301         "       .section        __ex_table,\"a\"                \n"     \
 302         "       " __UA_ADDR "   1b, 4b                          \n"     \
 303         "       " __UA_ADDR "   2b, 4b                          \n"     \
 304         "       .previous                                       \n"     \
 305         : "=r" (__gu_err), "=&r" (__gu_val)                             \
 306         : "0" (__gu_err), "o" (__m(__gu_addr)),                         \
 307           "o" (__m(__gu_addr + 4)), "i" (-EFAULT));                     \
 308 })
 309
 310 extern void __get_user_unknown(void);
 311
 312 /*
 313  * Yuck.  We need two variants, one for 64bit operation and one
 314  * for 32 bit mode and old iron.
 315  */
 316 #ifdef __mips64
 317 #define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val)
 318 #else
 319 #define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val)
 320 #endif
 321
 322 #define __put_user_nocheck(x,ptr,size)                                  \
 323 ({                                                                      \
 324         long __pu_err = 0;                                              \
 325         __typeof__(*(ptr)) __pu_val;                                    \
 326         long __pu_addr;                                                 \
 327         __pu_val = (x);                                                 \
 328         __pu_addr = (long) (ptr);                                       \
 329         switch (size) {                                                 \
 330         case 1: __put_user_asm("sb", __pu_val); break;                  \
 331         case 2: __put_user_asm("sh", __pu_val); break;                  \
 332         case 4: __put_user_asm("sw", __pu_val); break;                  \
 333         case 8: __PUT_USER_DW(__pu_val); break;                         \
 334         default: __put_user_unknown(); break;                           \
 335         }                                                               \
 336         __pu_err;                                                       \
 337 })
 338
 339 #define __put_user_check(x,ptr,size)                                    \
 340 ({                                                                      \
 341         __typeof__(*(ptr)) __pu_val = (x);                              \
 342         long __pu_addr = (long) (ptr);                                  \
 343         long __pu_err;                                                  \
 344                                                                         \
 345         __pu_err = verify_area(VERIFY_WRITE, (void *) __pu_addr, size); \
 346                                                                         \
 347         if (likely(!__pu_err)) {                                        \
 348                 switch (size) {                                         \
 349                 case 1: __put_user_asm("sb", __pu_val); break;          \
 350                 case 2: __put_user_asm("sh", __pu_val); break;          \
 351                 case 4: __put_user_asm("sw", __pu_val); break;          \
 352                 case 8: __PUT_USER_DW(__pu_val); break;                 \
 353                 default: __put_user_unknown(); break;                   \
 354                 }                                                       \
 355         }                                                               \
 356         __pu_err;                                                       \
 357 })
 358
 359 #define __put_user_asm(insn, __pu_val)                                  \
 360 ({                                                                      \
 361         __asm__ __volatile__(                                           \
 362         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 363         "2:                                                     \n"     \
 364         "       .section        .fixup,\"ax\"                   \n"     \
 365         "3:     li      %0, %4                                  \n"     \
 366         "       j       2b                                      \n"     \
 367         "       .previous                                       \n"     \
 368         "       .section        __ex_table,\"a\"                \n"     \
 369         "       " __UA_ADDR "   1b, 3b                          \n"     \
 370         "       .previous                                       \n"     \
 371         : "=r" (__pu_err)                                               \
 372         : "0" (__pu_err), "Jr" (__pu_val), "o" (__m(__pu_addr)),        \
 373           "i" (-EFAULT));                                               \
 374 })
 375
 376 #define __put_user_asm_ll32(__pu_val)                                   \
 377 ({                                                                      \
 378         __asm__ __volatile__(                                           \
 379         "1:     sw      %2, %3          # __put_user_asm_ll32   \n"     \
 380         "2:     sw      %D2, %4                                 \n"     \
 381         "3:                                                     \n"     \
 382         "       .section        .fixup,\"ax\"                   \n"     \
 383         "4:     li      %0, %5                                  \n"     \
 384         "       j       3b                                      \n"     \
 385         "       .previous                                       \n"     \
 386         "       .section        __ex_table,\"a\"                \n"     \
 387         "       " __UA_ADDR "   1b, 4b                          \n"     \
 388         "       " __UA_ADDR "   2b, 4b                          \n"     \
 389         "       .previous"                                              \
 390         : "=r" (__pu_err)                                               \
 391         : "0" (__pu_err), "r" (__pu_val), "o" (__m(__pu_addr)),         \
 392           "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                     \
 393 })
 394
 395 extern void __put_user_unknown(void);
 396
 397 /*
 398  * We're generating jump to subroutines which will be outside the range of
 399  * jump instructions
 400  */
 401 #ifdef MODULE
 402 #define __MODULE_JAL(destination)                                       \
 403         ".set\tnoat\n\t"                                                \
 404         __UA_LA "\t$1, " #destination "\n\t"                            \
 405         "jalr\t$1\n\t"                                                  \
 406         ".set\tat\n\t"
 407 #else
 408 #define __MODULE_JAL(destination)                                       \
 409         "jal\t" #destination "\n\t"
 410 #endif
 411
 412 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 413
 414 #define __invoke_copy_to_user(to,from,n)                                \
 415 ({                                                                      \
 416         register void *__cu_to_r __asm__ ("$4");                        \
 417         register const void *__cu_from_r __asm__ ("$5");                \
 418         register long __cu_len_r __asm__ ("$6");                        \
 419                                                                         \
 420         __cu_to_r = (to);                                               \
 421         __cu_from_r = (from);                                           \
 422         __cu_len_r = (n);                                               \
 423         __asm__ __volatile__(                                           \
 424         __MODULE_JAL(__copy_user)                                       \
 425         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 426         :                                                               \
 427         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 428           "memory");                                                    \
 429         __cu_len_r;                                                     \
 430 })
 431
 432 /*
 433  * __copy_to_user: - Copy a block of data into user space, with less checking.
 434  * @to:   Destination address, in user space.
 435  * @from: Source address, in kernel space.
 436  * @n:    Number of bytes to copy.
 437  *
 438  * Context: User context only.  This function may sleep.
 439  *
 440  * Copy data from kernel space to user space.  Caller must check
 441  * the specified block with access_ok() before calling this function.
 442  *
 443  * Returns number of bytes that could not be copied.
 444  * On success, this will be zero.
 445  */
 446 #define __copy_to_user(to,from,n)                                       \
 447 ({                                                                      \
 448         void *__cu_to;                                                  \
 449         const void *__cu_from;                                          \
 450         long __cu_len;                                                  \
 451                                                                         \
 452         __cu_to = (to);                                                 \
 453         __cu_from = (from);                                             \
 454         __cu_len = (n);                                                 \
 455         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 456         __cu_len;                                                       \
 457 })
 458
 459 #define __copy_to_user_inatomic __copy_to_user
 460 #define __copy_from_user_inatomic __copy_from_user
 461
 462 /*
 463  * copy_to_user: - Copy a block of data into user space.
 464  * @to:   Destination address, in user space.
 465  * @from: Source address, in kernel space.
 466  * @n:    Number of bytes to copy.
 467  *
 468  * Context: User context only.  This function may sleep.
 469  *
 470  * Copy data from kernel space to user space.
 471  *
 472  * Returns number of bytes that could not be copied.
 473  * On success, this will be zero.
 474  */
 475 #define copy_to_user(to,from,n)                                         \
 476 ({                                                                      \
 477         void *__cu_to;                                                  \
 478         const void *__cu_from;                                          \
 479         long __cu_len;                                                  \
 480                                                                         \
 481         __cu_to = (to);                                                 \
 482         __cu_from = (from);                                             \
 483         __cu_len = (n);                                                 \
 484         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 485                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 486                                                  __cu_len);             \
 487         __cu_len;                                                       \
 488 })
 489
 490 #define __invoke_copy_from_user(to,from,n)                              \
 491 ({                                                                      \
 492         register void *__cu_to_r __asm__ ("$4");                        \
 493         register const void *__cu_from_r __asm__ ("$5");                \
 494         register long __cu_len_r __asm__ ("$6");                        \
 495                                                                         \
 496         __cu_to_r = (to);                                               \
 497         __cu_from_r = (from);                                           \
 498         __cu_len_r = (n);                                               \
 499         __asm__ __volatile__(                                           \
 500         ".set\tnoreorder\n\t"                                           \
 501         __MODULE_JAL(__copy_user)                                       \
 502         ".set\tnoat\n\t"                                                \
 503         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 504         ".set\tat\n\t"                                                  \
 505         ".set\treorder"                                                 \
 506         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 507         :                                                               \
 508         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 509           "memory");                                                    \
 510         __cu_len_r;                                                     \
 511 })
 512
 513 /*
 514  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 515  * @from: Source address, in user space.
 516  * @n:    Number of bytes to copy.
 517  *
 518  * Context: User context only.  This function may sleep.
 519  *
 520  * Copy data from user space to kernel space.  Caller must check
 521  * the specified block with access_ok() before calling this function.
 522  *
 523  * Returns number of bytes that could not be copied.
 524  * On success, this will be zero.
 525  *
 526  * If some data could not be copied, this function will pad the copied
 527  * data to the requested size using zero bytes.
 528  */
 529 #define __copy_from_user(to,from,n)                                     \
 530 ({                                                                      \
 531         void *__cu_to;                                                  \
 532         const void *__cu_from;                                          \
 533         long __cu_len;                                                  \
 534                                                                         \
 535         __cu_to = (to);                                                 \
 536         __cu_from = (from);                                             \
 537         __cu_len = (n);                                                 \
 538         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 539                                            __cu_len);                   \
 540         __cu_len;                                                       \
 541 })
 542
 543 /*
 544  * copy_from_user: - Copy a block of data from user space.
 545  * @to:   Destination address, in kernel space.
 546  * @from: Source address, in user space.
 547  * @n:    Number of bytes to copy.
 548  *
 549  * Context: User context only.  This function may sleep.
 550  *
 551  * Copy data from user space to kernel space.
 552  *
 553  * Returns number of bytes that could not be copied.
 554  * On success, this will be zero.
 555  *
 556  * If some data could not be copied, this function will pad the copied
 557  * data to the requested size using zero bytes.
 558  */
 559 #define copy_from_user(to,from,n)                                       \
 560 ({                                                                      \
 561         void *__cu_to;                                                  \
 562         const void *__cu_from;                                          \
 563         long __cu_len;                                                  \
 564                                                                         \
 565         __cu_to = (to);                                                 \
 566         __cu_from = (from);                                             \
 567         __cu_len = (n);                                                 \
 568         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 569                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 570                                                    __cu_len);           \
 571         __cu_len;                                                       \
 572 })
 573
 574 /*
 575  * __clear_user: - Zero a block of memory in user space, with less checking.
 576  * @to:   Destination address, in user space.
 577  * @n:    Number of bytes to zero.
 578  *
 579  * Zero a block of memory in user space.  Caller must check
 580  * the specified block with access_ok() before calling this function.
 581  *
 582  * Returns number of bytes that could not be cleared.
 583  * On success, this will be zero.
 584  */
 585 static inline __kernel_size_t
 586 __clear_user(void *addr, __kernel_size_t size)
 587 {
 588         __kernel_size_t res;
 589
 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 * __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 *__from, long __len)
 635 {
 636         long res;
 637
 638         __asm__ __volatile__(
 639                 "move\t$4, %1\n\t"
 640                 "move\t$5, %2\n\t"
 641                 "move\t$6, %3\n\t"
 642                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 643                 "move\t%0, $2"
 644                 : "=r" (res)
 645                 : "r" (__to), "r" (__from), "r" (__len)
 646                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 647
 648         return res;
 649 }
 650
 651 /*
 652  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 653  * @dst:   Destination address, in kernel space.  This buffer must be at
 654  *         least @count bytes long.
 655  * @src:   Source address, in user space.
 656  * @count: Maximum number of bytes to copy, including the trailing NUL.
 657  *
 658  * Copies a NUL-terminated string from userspace to kernel space.
 659  *
 660  * On success, returns the length of the string (not including the trailing
 661  * NUL).
 662  *
 663  * If access to userspace fails, returns -EFAULT (some data may have been
 664  * copied).
 665  *
 666  * If @count is smaller than the length of the string, copies @count bytes
 667  * and returns @count.
 668  */
 669 static inline long
 670 strncpy_from_user(char *__to, const char *__from, long __len)
 671 {
 672         long res;
 673
 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 *s)
 689 {
 690         long res;
 691
 692         __asm__ __volatile__(
 693                 "move\t$4, %1\n\t"
 694                 __MODULE_JAL(__strlen_user_nocheck_asm)
 695                 "move\t%0, $2"
 696                 : "=r" (res)
 697                 : "r" (s)
 698                 : "$2", "$4", __UA_t0, "$31");
 699
 700         return res;
 701 }
 702
 703 /*
 704  * strlen_user: - Get the size of a string in user space.
 705  * @str: The string to measure.
 706  *
 707  * Context: User context only.  This function may sleep.
 708  *
 709  * Get the size of a NUL-terminated string in user space.
 710  *
 711  * Returns the size of the string INCLUDING the terminating NUL.
 712  * On exception, returns 0.
 713  *
 714  * If there is a limit on the length of a valid string, you may wish to
 715  * consider using strnlen_user() instead.
 716  */
 717 static inline long strlen_user(const char *s)
 718 {
 719         long res;
 720
 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 *s, long n)
 734 {
 735         long res;
 736
 737         __asm__ __volatile__(
 738                 "move\t$4, %1\n\t"
 739                 "move\t$5, %2\n\t"
 740                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 741                 "move\t%0, $2"
 742                 : "=r" (res)
 743                 : "r" (s), "r" (n)
 744                 : "$2", "$4", "$5", __UA_t0, "$31");
 745
 746         return res;
 747 }
 748
 749 /*
 750  * strlen_user: - Get the size of a string in user space.
 751  * @str: The string to measure.
 752  *
 753  * Context: User context only.  This function may sleep.
 754  *
 755  * Get the size of a NUL-terminated string in user space.
 756  *
 757  * Returns the size of the string INCLUDING the terminating NUL.
 758  * On exception, returns 0.
 759  *
 760  * If there is a limit on the length of a valid string, you may wish to
 761  * consider using strnlen_user() instead.
 762  */
 763 static inline long strnlen_user(const char *s, long n)
 764 {
 765         long res;
 766
 767         __asm__ __volatile__(
 768                 "move\t$4, %1\n\t"
 769                 "move\t$5, %2\n\t"
 770                 __MODULE_JAL(__strnlen_user_asm)
 771                 "move\t%0, $2"
 772                 : "=r" (res)
 773                 : "r" (s), "r" (n)
 774                 : "$2", "$4", "$5", __UA_t0, "$31");
 775
 776         return res;
 777 }
 778
 779 struct exception_table_entry
 780 {
 781         unsigned long insn;
 782         unsigned long nextinsn;
 783 };
 784
 785 /* Returns 0 if exception not found and fixup.unit otherwise.  */
 786 extern unsigned long search_exception_table(unsigned long addr);
 787
 788 /* Returns the new pc */
 789 #define fixup_exception(map_reg, fixup_unit, pc)                        \
 790 ({                                                                      \
 791         fixup_unit;                                                     \
 792 })
 793
 794 #endif /* _ASM_UACCESS_H */