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 *)(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(__gu_err) __get_user_asm("ld", __gu_err)
 207 #else
 208 #define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err)
 209 #endif
 210
 211 #define __get_user_nocheck(x,ptr,size)                                  \
 212 ({                                                                      \
 213         __typeof(*(ptr)) __gu_val = 0;                                  \
 214         long __gu_addr;                                                 \
 215         long __gu_err = 0;                                              \
 216                                                                         \
 217         might_sleep();                                                  \
 218         __gu_addr = (long) (ptr);                                       \
 219         switch (size) {                                                 \
 220         case 1: __get_user_asm("lb", __gu_err); break;                  \
 221         case 2: __get_user_asm("lh", __gu_err); break;                  \
 222         case 4: __get_user_asm("lw", __gu_err); break;                  \
 223         case 8: __GET_USER_DW(__gu_err); break;                         \
 224         default: __get_user_unknown(); break;                           \
 225         }                                                               \
 226         x = (__typeof__(*(ptr))) __gu_val;                              \
 227         __gu_err;                                                       \
 228 })
 229
 230 #define __get_user_check(x,ptr,size)                                    \
 231 ({                                                                      \
 232         __typeof__(*(ptr)) __gu_val = 0;                                \
 233         long __gu_addr;                                                 \
 234         long __gu_err;                                                  \
 235                                                                         \
 236         might_sleep();                                                  \
 237         __gu_addr = (long) (ptr);                                       \
 238         __gu_err = access_ok(VERIFY_READ, (void *) __gu_addr, size)     \
 239                                 ? 0 : -EFAULT;                          \
 240                                                                         \
 241         if (likely(!__gu_err)) {                                        \
 242                 switch (size) {                                         \
 243                 case 1: __get_user_asm("lb", __gu_err); break;          \
 244                 case 2: __get_user_asm("lh", __gu_err); break;          \
 245                 case 4: __get_user_asm("lw", __gu_err); break;          \
 246                 case 8: __GET_USER_DW(__gu_err); break;                 \
 247                 default: __get_user_unknown(); break;                   \
 248                 }                                                       \
 249         }                                                               \
 250         x = (__typeof__(*(ptr))) __gu_val;                              \
 251         __gu_err;                                                       \
 252 })
 253
 254 #define __get_user_asm(insn,__gu_err)                                   \
 255 ({                                                                      \
 256         __asm__ __volatile__(                                           \
 257         "1:     " insn "        %1, %3                          \n"     \
 258         "2:                                                     \n"     \
 259         "       .section .fixup,\"ax\"                          \n"     \
 260         "3:     li      %0, %4                                  \n"     \
 261         "       j       2b                                      \n"     \
 262         "       .previous                                       \n"     \
 263         "       .section __ex_table,\"a\"                       \n"     \
 264         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 265         "       .previous                                       \n"     \
 266         : "=r" (__gu_err), "=r" (__gu_val)                              \
 267         : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT));         \
 268 })
 269
 270 /*
 271  * Get a long long 64 using 32 bit registers.
 272  */
 273 #define __get_user_asm_ll32(__gu_err)                                   \
 274 ({                                                                      \
 275         __asm__ __volatile__(                                           \
 276         "1:     lw      %1, %3                                  \n"     \
 277         "2:     lw      %D1, %4                                 \n"     \
 278         "       move    %0, $0                                  \n"     \
 279         "3:     .section        .fixup,\"ax\"                   \n"     \
 280         "4:     li      %0, %5                                  \n"     \
 281         "       move    %1, $0                                  \n"     \
 282         "       move    %D1, $0                                 \n"     \
 283         "       j       3b                                      \n"     \
 284         "       .previous                                       \n"     \
 285         "       .section        __ex_table,\"a\"                \n"     \
 286         "       " __UA_ADDR "   1b, 4b                          \n"     \
 287         "       " __UA_ADDR "   2b, 4b                          \n"     \
 288         "       .previous                                       \n"     \
 289         : "=r" (__gu_err), "=&r" (__gu_val)                             \
 290         : "0" (__gu_err), "o" (__m(__gu_addr)),                         \
 291           "o" (__m(__gu_addr + 4)), "i" (-EFAULT));                     \
 292 })
 293
 294 extern void __get_user_unknown(void);
 295
 296 /*
 297  * Yuck.  We need two variants, one for 64bit operation and one
 298  * for 32 bit mode and old iron.
 299  */
 300 #ifdef __mips64
 301 #define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val)
 302 #else
 303 #define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val)
 304 #endif
 305
 306 #define __put_user_nocheck(x,ptr,size)                                  \
 307 ({                                                                      \
 308         __typeof__(*(ptr)) __pu_val;                                    \
 309         long __pu_addr;                                                 \
 310         long __pu_err = 0;                                              \
 311                                                                         \
 312         might_sleep();                                                  \
 313         __pu_val = (x);                                                 \
 314         __pu_addr = (long) (ptr);                                       \
 315         switch (size) {                                                 \
 316         case 1: __put_user_asm("sb", __pu_val); break;                  \
 317         case 2: __put_user_asm("sh", __pu_val); break;                  \
 318         case 4: __put_user_asm("sw", __pu_val); break;                  \
 319         case 8: __PUT_USER_DW(__pu_val); break;                         \
 320         default: __put_user_unknown(); break;                           \
 321         }                                                               \
 322         __pu_err;                                                       \
 323 })
 324
 325 #define __put_user_check(x,ptr,size)                                    \
 326 ({                                                                      \
 327         __typeof__(*(ptr)) __pu_val;                                    \
 328         long __pu_addr;                                                 \
 329         long __pu_err;                                                  \
 330                                                                         \
 331         might_sleep();                                                  \
 332         __pu_val = (x);                                                 \
 333         __pu_addr = (long) (ptr);                                       \
 334         __pu_err = access_ok(VERIFY_WRITE, (void *) __pu_addr, size)    \
 335                                 ? 0 : -EFAULT;                          \
 336                                                                         \
 337         if (likely(!__pu_err)) {                                        \
 338                 switch (size) {                                         \
 339                 case 1: __put_user_asm("sb", __pu_val); break;          \
 340                 case 2: __put_user_asm("sh", __pu_val); break;          \
 341                 case 4: __put_user_asm("sw", __pu_val); break;          \
 342                 case 8: __PUT_USER_DW(__pu_val); break;                 \
 343                 default: __put_user_unknown(); break;                   \
 344                 }                                                       \
 345         }                                                               \
 346         __pu_err;                                                       \
 347 })
 348
 349 #define __put_user_asm(insn, __pu_val)                                  \
 350 ({                                                                      \
 351         __asm__ __volatile__(                                           \
 352         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 353         "2:                                                     \n"     \
 354         "       .section        .fixup,\"ax\"                   \n"     \
 355         "3:     li      %0, %4                                  \n"     \
 356         "       j       2b                                      \n"     \
 357         "       .previous                                       \n"     \
 358         "       .section        __ex_table,\"a\"                \n"     \
 359         "       " __UA_ADDR "   1b, 3b                          \n"     \
 360         "       .previous                                       \n"     \
 361         : "=r" (__pu_err)                                               \
 362         : "0" (__pu_err), "Jr" (__pu_val), "o" (__m(__pu_addr)),        \
 363           "i" (-EFAULT));                                               \
 364 })
 365
 366 #define __put_user_asm_ll32(__pu_val)                                   \
 367 ({                                                                      \
 368         __asm__ __volatile__(                                           \
 369         "1:     sw      %2, %3          # __put_user_asm_ll32   \n"     \
 370         "2:     sw      %D2, %4                                 \n"     \
 371         "3:                                                     \n"     \
 372         "       .section        .fixup,\"ax\"                   \n"     \
 373         "4:     li      %0, %5                                  \n"     \
 374         "       j       3b                                      \n"     \
 375         "       .previous                                       \n"     \
 376         "       .section        __ex_table,\"a\"                \n"     \
 377         "       " __UA_ADDR "   1b, 4b                          \n"     \
 378         "       " __UA_ADDR "   2b, 4b                          \n"     \
 379         "       .previous"                                              \
 380         : "=r" (__pu_err)                                               \
 381         : "0" (__pu_err), "r" (__pu_val), "o" (__m(__pu_addr)),         \
 382           "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                     \
 383 })
 384
 385 extern void __put_user_unknown(void);
 386
 387 /*
 388  * We're generating jump to subroutines which will be outside the range of
 389  * jump instructions
 390  */
 391 #ifdef MODULE
 392 #define __MODULE_JAL(destination)                                       \
 393         ".set\tnoat\n\t"                                                \
 394         __UA_LA "\t$1, " #destination "\n\t"                            \
 395         "jalr\t$1\n\t"                                                  \
 396         ".set\tat\n\t"
 397 #else
 398 #define __MODULE_JAL(destination)                                       \
 399         "jal\t" #destination "\n\t"
 400 #endif
 401
 402 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 403
 404 #define __invoke_copy_to_user(to,from,n)                                \
 405 ({                                                                      \
 406         register void *__cu_to_r __asm__ ("$4");                        \
 407         register const void *__cu_from_r __asm__ ("$5");                \
 408         register long __cu_len_r __asm__ ("$6");                        \
 409                                                                         \
 410         __cu_to_r = (to);                                               \
 411         __cu_from_r = (from);                                           \
 412         __cu_len_r = (n);                                               \
 413         __asm__ __volatile__(                                           \
 414         __MODULE_JAL(__copy_user)                                       \
 415         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 416         :                                                               \
 417         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 418           "memory");                                                    \
 419         __cu_len_r;                                                     \
 420 })
 421
 422 /*
 423  * __copy_to_user: - Copy a block of data into user space, with less checking.
 424  * @to:   Destination address, in user space.
 425  * @from: Source address, in kernel space.
 426  * @n:    Number of bytes to copy.
 427  *
 428  * Context: User context only.  This function may sleep.
 429  *
 430  * Copy data from kernel space to user space.  Caller must check
 431  * the specified block with access_ok() before calling this function.
 432  *
 433  * Returns number of bytes that could not be copied.
 434  * On success, this will be zero.
 435  */
 436 #define __copy_to_user(to,from,n)                                       \
 437 ({                                                                      \
 438         void *__cu_to;                                                  \
 439         const void *__cu_from;                                          \
 440         long __cu_len;                                                  \
 441                                                                         \
 442         might_sleep();                                                  \
 443         __cu_to = (to);                                                 \
 444         __cu_from = (from);                                             \
 445         __cu_len = (n);                                                 \
 446         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 447         __cu_len;                                                       \
 448 })
 449
 450 #define __copy_to_user_inatomic __copy_to_user
 451 #define __copy_from_user_inatomic __copy_from_user
 452
 453 /*
 454  * copy_to_user: - Copy a block of data into user space.
 455  * @to:   Destination address, in user space.
 456  * @from: Source address, in kernel space.
 457  * @n:    Number of bytes to copy.
 458  *
 459  * Context: User context only.  This function may sleep.
 460  *
 461  * Copy data from kernel space to user space.
 462  *
 463  * Returns number of bytes that could not be copied.
 464  * On success, this will be zero.
 465  */
 466 #define copy_to_user(to,from,n)                                         \
 467 ({                                                                      \
 468         void *__cu_to;                                                  \
 469         const void *__cu_from;                                          \
 470         long __cu_len;                                                  \
 471                                                                         \
 472         might_sleep();                                                  \
 473         __cu_to = (to);                                                 \
 474         __cu_from = (from);                                             \
 475         __cu_len = (n);                                                 \
 476         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 477                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 478                                                  __cu_len);             \
 479         __cu_len;                                                       \
 480 })
 481
 482 #define __invoke_copy_from_user(to,from,n)                              \
 483 ({                                                                      \
 484         register void *__cu_to_r __asm__ ("$4");                        \
 485         register const void *__cu_from_r __asm__ ("$5");                \
 486         register long __cu_len_r __asm__ ("$6");                        \
 487                                                                         \
 488         __cu_to_r = (to);                                               \
 489         __cu_from_r = (from);                                           \
 490         __cu_len_r = (n);                                               \
 491         __asm__ __volatile__(                                           \
 492         ".set\tnoreorder\n\t"                                           \
 493         __MODULE_JAL(__copy_user)                                       \
 494         ".set\tnoat\n\t"                                                \
 495         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 496         ".set\tat\n\t"                                                  \
 497         ".set\treorder"                                                 \
 498         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 499         :                                                               \
 500         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 501           "memory");                                                    \
 502         __cu_len_r;                                                     \
 503 })
 504
 505 /*
 506  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 507  * @from: Source address, in user space.
 508  * @n:    Number of bytes to copy.
 509  *
 510  * Context: User context only.  This function may sleep.
 511  *
 512  * Copy data from user space to kernel space.  Caller must check
 513  * the specified block with access_ok() before calling this function.
 514  *
 515  * Returns number of bytes that could not be copied.
 516  * On success, this will be zero.
 517  *
 518  * If some data could not be copied, this function will pad the copied
 519  * data to the requested size using zero bytes.
 520  */
 521 #define __copy_from_user(to,from,n)                                     \
 522 ({                                                                      \
 523         void *__cu_to;                                                  \
 524         const void *__cu_from;                                          \
 525         long __cu_len;                                                  \
 526                                                                         \
 527         might_sleep();                                                  \
 528         __cu_to = (to);                                                 \
 529         __cu_from = (from);                                             \
 530         __cu_len = (n);                                                 \
 531         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 532                                            __cu_len);                   \
 533         __cu_len;                                                       \
 534 })
 535
 536 /*
 537  * copy_from_user: - Copy a block of data from user space.
 538  * @to:   Destination address, in kernel space.
 539  * @from: Source address, in user space.
 540  * @n:    Number of bytes to copy.
 541  *
 542  * Context: User context only.  This function may sleep.
 543  *
 544  * Copy data from user space to kernel space.
 545  *
 546  * Returns number of bytes that could not be copied.
 547  * On success, this will be zero.
 548  *
 549  * If some data could not be copied, this function will pad the copied
 550  * data to the requested size using zero bytes.
 551  */
 552 #define copy_from_user(to,from,n)                                       \
 553 ({                                                                      \
 554         void *__cu_to;                                                  \
 555         const void *__cu_from;                                          \
 556         long __cu_len;                                                  \
 557                                                                         \
 558         might_sleep();                                                  \
 559         __cu_to = (to);                                                 \
 560         __cu_from = (from);                                             \
 561         __cu_len = (n);                                                 \
 562         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 563                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 564                                                    __cu_len);           \
 565         __cu_len;                                                       \
 566 })
 567
 568 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 569
 570 #define copy_in_user(to,from,n)                                         \
 571 ({                                                                      \
 572         void *__cu_to;                                                  \
 573         const void *__cu_from;                                          \
 574         long __cu_len;                                                  \
 575                                                                         \
 576         might_sleep();                                                  \
 577         __cu_to = (to);                                                 \
 578         __cu_from = (from);                                             \
 579         __cu_len = (n);                                                 \
 580         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 581                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 582                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 583                                                    __cu_len);           \
 584         __cu_len;                                                       \
 585 })
 586
 587 /*
 588  * __clear_user: - Zero a block of memory in user space, with less checking.
 589  * @to:   Destination address, in user space.
 590  * @n:    Number of bytes to zero.
 591  *
 592  * Zero a block of memory in user space.  Caller must check
 593  * the specified block with access_ok() before calling this function.
 594  *
 595  * Returns number of bytes that could not be cleared.
 596  * On success, this will be zero.
 597  */
 598 static inline __kernel_size_t
 599 __clear_user(void *addr, __kernel_size_t size)
 600 {
 601         __kernel_size_t res;
 602
 603         might_sleep();
 604         __asm__ __volatile__(
 605                 "move\t$4, %1\n\t"
 606                 "move\t$5, $0\n\t"
 607                 "move\t$6, %2\n\t"
 608                 __MODULE_JAL(__bzero)
 609                 "move\t%0, $6"
 610                 : "=r" (res)
 611                 : "r" (addr), "r" (size)
 612                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 613
 614         return res;
 615 }
 616
 617 #define clear_user(addr,n)                                              \
 618 ({                                                                      \
 619         void * __cl_addr = (addr);                                      \
 620         unsigned long __cl_size = (n);                                  \
 621         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 622                 ((unsigned long)(__cl_addr)), __cl_size))               \
 623                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 624         __cl_size;                                                      \
 625 })
 626
 627 /*
 628  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 629  * @dst:   Destination address, in kernel space.  This buffer must be at
 630  *         least @count bytes long.
 631  * @src:   Source address, in user space.
 632  * @count: Maximum number of bytes to copy, including the trailing NUL.
 633  *
 634  * Copies a NUL-terminated string from userspace to kernel space.
 635  * Caller must check the specified block with access_ok() before calling
 636  * this function.
 637  *
 638  * On success, returns the length of the string (not including the trailing
 639  * NUL).
 640  *
 641  * If access to userspace fails, returns -EFAULT (some data may have been
 642  * copied).
 643  *
 644  * If @count is smaller than the length of the string, copies @count bytes
 645  * and returns @count.
 646  */
 647 static inline long
 648 __strncpy_from_user(char *__to, const char *__from, long __len)
 649 {
 650         long res;
 651
 652         might_sleep();
 653         __asm__ __volatile__(
 654                 "move\t$4, %1\n\t"
 655                 "move\t$5, %2\n\t"
 656                 "move\t$6, %3\n\t"
 657                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 658                 "move\t%0, $2"
 659                 : "=r" (res)
 660                 : "r" (__to), "r" (__from), "r" (__len)
 661                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 662
 663         return res;
 664 }
 665
 666 /*
 667  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 668  * @dst:   Destination address, in kernel space.  This buffer must be at
 669  *         least @count bytes long.
 670  * @src:   Source address, in user space.
 671  * @count: Maximum number of bytes to copy, including the trailing NUL.
 672  *
 673  * Copies a NUL-terminated string from userspace to kernel space.
 674  *
 675  * On success, returns the length of the string (not including the trailing
 676  * NUL).
 677  *
 678  * If access to userspace fails, returns -EFAULT (some data may have been
 679  * copied).
 680  *
 681  * If @count is smaller than the length of the string, copies @count bytes
 682  * and returns @count.
 683  */
 684 static inline long
 685 strncpy_from_user(char *__to, const char *__from, long __len)
 686 {
 687         long res;
 688
 689         might_sleep();
 690         __asm__ __volatile__(
 691                 "move\t$4, %1\n\t"
 692                 "move\t$5, %2\n\t"
 693                 "move\t$6, %3\n\t"
 694                 __MODULE_JAL(__strncpy_from_user_asm)
 695                 "move\t%0, $2"
 696                 : "=r" (res)
 697                 : "r" (__to), "r" (__from), "r" (__len)
 698                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 699
 700         return res;
 701 }
 702
 703 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 704 static inline long __strlen_user(const char *s)
 705 {
 706         long res;
 707
 708         might_sleep();
 709         __asm__ __volatile__(
 710                 "move\t$4, %1\n\t"
 711                 __MODULE_JAL(__strlen_user_nocheck_asm)
 712                 "move\t%0, $2"
 713                 : "=r" (res)
 714                 : "r" (s)
 715                 : "$2", "$4", __UA_t0, "$31");
 716
 717         return res;
 718 }
 719
 720 /*
 721  * strlen_user: - Get the size of a string in user space.
 722  * @str: The string to measure.
 723  *
 724  * Context: User context only.  This function may sleep.
 725  *
 726  * Get the size of a NUL-terminated string in user space.
 727  *
 728  * Returns the size of the string INCLUDING the terminating NUL.
 729  * On exception, returns 0.
 730  *
 731  * If there is a limit on the length of a valid string, you may wish to
 732  * consider using strnlen_user() instead.
 733  */
 734 static inline long strlen_user(const char *s)
 735 {
 736         long res;
 737
 738         might_sleep();
 739         __asm__ __volatile__(
 740                 "move\t$4, %1\n\t"
 741                 __MODULE_JAL(__strlen_user_asm)
 742                 "move\t%0, $2"
 743                 : "=r" (res)
 744                 : "r" (s)
 745                 : "$2", "$4", __UA_t0, "$31");
 746
 747         return res;
 748 }
 749
 750 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 751 static inline long __strnlen_user(const char *s, long n)
 752 {
 753         long res;
 754
 755         might_sleep();
 756         __asm__ __volatile__(
 757                 "move\t$4, %1\n\t"
 758                 "move\t$5, %2\n\t"
 759                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 760                 "move\t%0, $2"
 761                 : "=r" (res)
 762                 : "r" (s), "r" (n)
 763                 : "$2", "$4", "$5", __UA_t0, "$31");
 764
 765         return res;
 766 }
 767
 768 /*
 769  * strlen_user: - Get the size of a string in user space.
 770  * @str: The string to measure.
 771  *
 772  * Context: User context only.  This function may sleep.
 773  *
 774  * Get the size of a NUL-terminated string in user space.
 775  *
 776  * Returns the size of the string INCLUDING the terminating NUL.
 777  * On exception, returns 0.
 778  *
 779  * If there is a limit on the length of a valid string, you may wish to
 780  * consider using strnlen_user() instead.
 781  */
 782 static inline long strnlen_user(const char *s, long n)
 783 {
 784         long res;
 785
 786         might_sleep();
 787         __asm__ __volatile__(
 788                 "move\t$4, %1\n\t"
 789                 "move\t$5, %2\n\t"
 790                 __MODULE_JAL(__strnlen_user_asm)
 791                 "move\t%0, $2"
 792                 : "=r" (res)
 793                 : "r" (s), "r" (n)
 794                 : "$2", "$4", "$5", __UA_t0, "$31");
 795
 796         return res;
 797 }
 798
 799 struct exception_table_entry
 800 {
 801         unsigned long insn;
 802         unsigned long nextinsn;
 803 };
 804
 805 extern int fixup_exception(struct pt_regs *regs);
 806
 807 #endif /* _ASM_UACCESS_H */