include/asm-mips/uaccess.h

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