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_MIPS32
  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_MIPS32 */
  36
  37 #ifdef CONFIG_MIPS64
  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_MIPS64 */
  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  * verify_area: - Obsolete, use access_ok()
 116  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
 117  * @addr: User space pointer to start of block to check
 118  * @size: Size of block to check
 119  *
 120  * Context: User context only.  This function may sleep.
 121  *
 122  * This function has been replaced by access_ok().
 123  *
 124  * Checks if a pointer to a block of memory in user space is valid.
 125  *
 126  * Returns zero if the memory block may be valid, -EFAULT
 127  * if it is definitely invalid.
 128  *
 129  * See access_ok() for more details.
 130  */
 131 static inline int verify_area(int type, const void * addr, unsigned long size)
 132 {
 133         return access_ok(type, addr, size) ? 0 : -EFAULT;
 134 }
 135
 136 /*
 137  * put_user: - Write a simple value into user space.
 138  * @x:   Value to copy to user space.
 139  * @ptr: Destination address, in user space.
 140  *
 141  * Context: User context only.  This function may sleep.
 142  *
 143  * This macro copies a single simple value from kernel space to user
 144  * space.  It supports simple types like char and int, but not larger
 145  * data types like structures or arrays.
 146  *
 147  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 148  * to the result of dereferencing @ptr.
 149  *
 150  * Returns zero on success, or -EFAULT on error.
 151  */
 152 #define put_user(x,ptr) \
 153         __put_user_check((x),(ptr),sizeof(*(ptr)))
 154
 155 /*
 156  * get_user: - Get a simple variable from user space.
 157  * @x:   Variable to store result.
 158  * @ptr: Source address, in user space.
 159  *
 160  * Context: User context only.  This function may sleep.
 161  *
 162  * This macro copies a single simple variable from user space to kernel
 163  * space.  It supports simple types like char and int, but not larger
 164  * data types like structures or arrays.
 165  *
 166  * @ptr must have pointer-to-simple-variable type, and the result of
 167  * dereferencing @ptr must be assignable to @x without a cast.
 168  *
 169  * Returns zero on success, or -EFAULT on error.
 170  * On error, the variable @x is set to zero.
 171  */
 172 #define get_user(x,ptr) \
 173         __get_user_check((x),(ptr),sizeof(*(ptr)))
 174
 175 /*
 176  * __put_user: - Write a simple value into user space, with less checking.
 177  * @x:   Value to copy to user space.
 178  * @ptr: Destination address, in user space.
 179  *
 180  * Context: User context only.  This function may sleep.
 181  *
 182  * This macro copies a single simple value from kernel space to user
 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 @x must be assignable
 187  * to the result of dereferencing @ptr.
 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  */
 194 #define __put_user(x,ptr) \
 195         __put_user_nocheck((x),(ptr),sizeof(*(ptr)))
 196
 197 /*
 198  * __get_user: - Get a simple variable from user space, with less checking.
 199  * @x:   Variable to store result.
 200  * @ptr: Source address, in user space.
 201  *
 202  * Context: User context only.  This function may sleep.
 203  *
 204  * This macro copies a single simple variable from user space to kernel
 205  * space.  It supports simple types like char and int, but not larger
 206  * data types like structures or arrays.
 207  *
 208  * @ptr must have pointer-to-simple-variable type, and the result of
 209  * dereferencing @ptr must be assignable to @x without a cast.
 210  *
 211  * Caller must check the pointer with access_ok() before calling this
 212  * function.
 213  *
 214  * Returns zero on success, or -EFAULT on error.
 215  * On error, the variable @x is set to zero.
 216  */
 217 #define __get_user(x,ptr) \
 218         __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 219
 220 struct __large_struct { unsigned long buf[100]; };
 221 #define __m(x) (*(struct __large_struct *)(x))
 222
 223 /*
 224  * Yuck.  We need two variants, one for 64bit operation and one
 225  * for 32 bit mode and old iron.
 226  */
 227 #ifdef __mips64
 228 #define __GET_USER_DW(__gu_err) __get_user_asm("ld", __gu_err)
 229 #else
 230 #define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err)
 231 #endif
 232
 233 #define __get_user_nocheck(x,ptr,size)                                  \
 234 ({                                                                      \
 235         __typeof(*(ptr)) __gu_val = 0;                                  \
 236         long __gu_addr;                                                 \
 237         long __gu_err = 0;                                              \
 238                                                                         \
 239         might_sleep();                                                  \
 240         __gu_addr = (long) (ptr);                                       \
 241         switch (size) {                                                 \
 242         case 1: __get_user_asm("lb", __gu_err); break;                  \
 243         case 2: __get_user_asm("lh", __gu_err); break;                  \
 244         case 4: __get_user_asm("lw", __gu_err); break;                  \
 245         case 8: __GET_USER_DW(__gu_err); break;                         \
 246         default: __get_user_unknown(); break;                           \
 247         }                                                               \
 248         x = (__typeof__(*(ptr))) __gu_val;                              \
 249         __gu_err;                                                       \
 250 })
 251
 252 #define __get_user_check(x,ptr,size)                                    \
 253 ({                                                                      \
 254         __typeof__(*(ptr)) __gu_val = 0;                                \
 255         long __gu_addr;                                                 \
 256         long __gu_err;                                                  \
 257                                                                         \
 258         might_sleep();                                                  \
 259         __gu_addr = (long) (ptr);                                       \
 260         __gu_err = verify_area(VERIFY_READ, (void *) __gu_addr, size);  \
 261                                                                         \
 262         if (likely(!__gu_err)) {                                        \
 263                 switch (size) {                                         \
 264                 case 1: __get_user_asm("lb", __gu_err); break;          \
 265                 case 2: __get_user_asm("lh", __gu_err); break;          \
 266                 case 4: __get_user_asm("lw", __gu_err); break;          \
 267                 case 8: __GET_USER_DW(__gu_err); break;                 \
 268                 default: __get_user_unknown(); break;                   \
 269                 }                                                       \
 270         }                                                               \
 271         x = (__typeof__(*(ptr))) __gu_val;                              \
 272         __gu_err;                                                       \
 273 })
 274
 275 #define __get_user_asm(insn,__gu_err)                                   \
 276 ({                                                                      \
 277         __asm__ __volatile__(                                           \
 278         "1:     " insn "        %1, %3                          \n"     \
 279         "2:                                                     \n"     \
 280         "       .section .fixup,\"ax\"                          \n"     \
 281         "3:     li      %0, %4                                  \n"     \
 282         "       j       2b                                      \n"     \
 283         "       .previous                                       \n"     \
 284         "       .section __ex_table,\"a\"                       \n"     \
 285         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 286         "       .previous                                       \n"     \
 287         : "=r" (__gu_err), "=r" (__gu_val)                              \
 288         : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT));         \
 289 })
 290
 291 /*
 292  * Get a long long 64 using 32 bit registers.
 293  */
 294 #define __get_user_asm_ll32(__gu_err)                                   \
 295 ({                                                                      \
 296         __asm__ __volatile__(                                           \
 297         "1:     lw      %1, %3                                  \n"     \
 298         "2:     lw      %D1, %4                                 \n"     \
 299         "       move    %0, $0                                  \n"     \
 300         "3:     .section        .fixup,\"ax\"                   \n"     \
 301         "4:     li      %0, %5                                  \n"     \
 302         "       move    %1, $0                                  \n"     \
 303         "       move    %D1, $0                                 \n"     \
 304         "       j       3b                                      \n"     \
 305         "       .previous                                       \n"     \
 306         "       .section        __ex_table,\"a\"                \n"     \
 307         "       " __UA_ADDR "   1b, 4b                          \n"     \
 308         "       " __UA_ADDR "   2b, 4b                          \n"     \
 309         "       .previous                                       \n"     \
 310         : "=r" (__gu_err), "=&r" (__gu_val)                             \
 311         : "0" (__gu_err), "o" (__m(__gu_addr)),                         \
 312           "o" (__m(__gu_addr + 4)), "i" (-EFAULT));                     \
 313 })
 314
 315 extern void __get_user_unknown(void);
 316
 317 /*
 318  * Yuck.  We need two variants, one for 64bit operation and one
 319  * for 32 bit mode and old iron.
 320  */
 321 #ifdef __mips64
 322 #define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val)
 323 #else
 324 #define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val)
 325 #endif
 326
 327 #define __put_user_nocheck(x,ptr,size)                                  \
 328 ({                                                                      \
 329         __typeof__(*(ptr)) __pu_val;                                    \
 330         long __pu_addr;                                                 \
 331         long __pu_err = 0;                                              \
 332                                                                         \
 333         might_sleep();                                                  \
 334         __pu_val = (x);                                                 \
 335         __pu_addr = (long) (ptr);                                       \
 336         switch (size) {                                                 \
 337         case 1: __put_user_asm("sb", __pu_val); break;                  \
 338         case 2: __put_user_asm("sh", __pu_val); break;                  \
 339         case 4: __put_user_asm("sw", __pu_val); break;                  \
 340         case 8: __PUT_USER_DW(__pu_val); break;                         \
 341         default: __put_user_unknown(); break;                           \
 342         }                                                               \
 343         __pu_err;                                                       \
 344 })
 345
 346 #define __put_user_check(x,ptr,size)                                    \
 347 ({                                                                      \
 348         __typeof__(*(ptr)) __pu_val;                                    \
 349         long __pu_addr;                                                 \
 350         long __pu_err;                                                  \
 351                                                                         \
 352         might_sleep();                                                  \
 353         __pu_val = (x);                                                 \
 354         __pu_addr = (long) (ptr);                                       \
 355         __pu_err = verify_area(VERIFY_WRITE, (void *) __pu_addr, size); \
 356                                                                         \
 357         if (likely(!__pu_err)) {                                        \
 358                 switch (size) {                                         \
 359                 case 1: __put_user_asm("sb", __pu_val); break;          \
 360                 case 2: __put_user_asm("sh", __pu_val); break;          \
 361                 case 4: __put_user_asm("sw", __pu_val); break;          \
 362                 case 8: __PUT_USER_DW(__pu_val); break;                 \
 363                 default: __put_user_unknown(); break;                   \
 364                 }                                                       \
 365         }                                                               \
 366         __pu_err;                                                       \
 367 })
 368
 369 #define __put_user_asm(insn, __pu_val)                                  \
 370 ({                                                                      \
 371         __asm__ __volatile__(                                           \
 372         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 373         "2:                                                     \n"     \
 374         "       .section        .fixup,\"ax\"                   \n"     \
 375         "3:     li      %0, %4                                  \n"     \
 376         "       j       2b                                      \n"     \
 377         "       .previous                                       \n"     \
 378         "       .section        __ex_table,\"a\"                \n"     \
 379         "       " __UA_ADDR "   1b, 3b                          \n"     \
 380         "       .previous                                       \n"     \
 381         : "=r" (__pu_err)                                               \
 382         : "0" (__pu_err), "Jr" (__pu_val), "o" (__m(__pu_addr)),        \
 383           "i" (-EFAULT));                                               \
 384 })
 385
 386 #define __put_user_asm_ll32(__pu_val)                                   \
 387 ({                                                                      \
 388         __asm__ __volatile__(                                           \
 389         "1:     sw      %2, %3          # __put_user_asm_ll32   \n"     \
 390         "2:     sw      %D2, %4                                 \n"     \
 391         "3:                                                     \n"     \
 392         "       .section        .fixup,\"ax\"                   \n"     \
 393         "4:     li      %0, %5                                  \n"     \
 394         "       j       3b                                      \n"     \
 395         "       .previous                                       \n"     \
 396         "       .section        __ex_table,\"a\"                \n"     \
 397         "       " __UA_ADDR "   1b, 4b                          \n"     \
 398         "       " __UA_ADDR "   2b, 4b                          \n"     \
 399         "       .previous"                                              \
 400         : "=r" (__pu_err)                                               \
 401         : "0" (__pu_err), "r" (__pu_val), "o" (__m(__pu_addr)),         \
 402           "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                     \
 403 })
 404
 405 extern void __put_user_unknown(void);
 406
 407 /*
 408  * We're generating jump to subroutines which will be outside the range of
 409  * jump instructions
 410  */
 411 #ifdef MODULE
 412 #define __MODULE_JAL(destination)                                       \
 413         ".set\tnoat\n\t"                                                \
 414         __UA_LA "\t$1, " #destination "\n\t"                            \
 415         "jalr\t$1\n\t"                                                  \
 416         ".set\tat\n\t"
 417 #else
 418 #define __MODULE_JAL(destination)                                       \
 419         "jal\t" #destination "\n\t"
 420 #endif
 421
 422 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 423
 424 #define __invoke_copy_to_user(to,from,n)                                \
 425 ({                                                                      \
 426         register void *__cu_to_r __asm__ ("$4");                        \
 427         register const void *__cu_from_r __asm__ ("$5");                \
 428         register long __cu_len_r __asm__ ("$6");                        \
 429                                                                         \
 430         __cu_to_r = (to);                                               \
 431         __cu_from_r = (from);                                           \
 432         __cu_len_r = (n);                                               \
 433         __asm__ __volatile__(                                           \
 434         __MODULE_JAL(__copy_user)                                       \
 435         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 436         :                                                               \
 437         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 438           "memory");                                                    \
 439         __cu_len_r;                                                     \
 440 })
 441
 442 /*
 443  * __copy_to_user: - Copy a block of data into user space, with less checking.
 444  * @to:   Destination address, in user space.
 445  * @from: Source address, in kernel space.
 446  * @n:    Number of bytes to copy.
 447  *
 448  * Context: User context only.  This function may sleep.
 449  *
 450  * Copy data from kernel space to user space.  Caller must check
 451  * the specified block with access_ok() before calling this function.
 452  *
 453  * Returns number of bytes that could not be copied.
 454  * On success, this will be zero.
 455  */
 456 #define __copy_to_user(to,from,n)                                       \
 457 ({                                                                      \
 458         void *__cu_to;                                                  \
 459         const void *__cu_from;                                          \
 460         long __cu_len;                                                  \
 461                                                                         \
 462         might_sleep();                                                  \
 463         __cu_to = (to);                                                 \
 464         __cu_from = (from);                                             \
 465         __cu_len = (n);                                                 \
 466         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 467         __cu_len;                                                       \
 468 })
 469
 470 #define __copy_to_user_inatomic __copy_to_user
 471 #define __copy_from_user_inatomic __copy_from_user
 472
 473 /*
 474  * copy_to_user: - Copy a block of data into user space.
 475  * @to:   Destination address, in user space.
 476  * @from: Source address, in kernel space.
 477  * @n:    Number of bytes to copy.
 478  *
 479  * Context: User context only.  This function may sleep.
 480  *
 481  * Copy data from kernel space to user space.
 482  *
 483  * Returns number of bytes that could not be copied.
 484  * On success, this will be zero.
 485  */
 486 #define copy_to_user(to,from,n)                                         \
 487 ({                                                                      \
 488         void *__cu_to;                                                  \
 489         const void *__cu_from;                                          \
 490         long __cu_len;                                                  \
 491                                                                         \
 492         might_sleep();                                                  \
 493         __cu_to = (to);                                                 \
 494         __cu_from = (from);                                             \
 495         __cu_len = (n);                                                 \
 496         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 497                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 498                                                  __cu_len);             \
 499         __cu_len;                                                       \
 500 })
 501
 502 #define __invoke_copy_from_user(to,from,n)                              \
 503 ({                                                                      \
 504         register void *__cu_to_r __asm__ ("$4");                        \
 505         register const void *__cu_from_r __asm__ ("$5");                \
 506         register long __cu_len_r __asm__ ("$6");                        \
 507                                                                         \
 508         __cu_to_r = (to);                                               \
 509         __cu_from_r = (from);                                           \
 510         __cu_len_r = (n);                                               \
 511         __asm__ __volatile__(                                           \
 512         ".set\tnoreorder\n\t"                                           \
 513         __MODULE_JAL(__copy_user)                                       \
 514         ".set\tnoat\n\t"                                                \
 515         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 516         ".set\tat\n\t"                                                  \
 517         ".set\treorder"                                                 \
 518         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 519         :                                                               \
 520         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 521           "memory");                                                    \
 522         __cu_len_r;                                                     \
 523 })
 524
 525 /*
 526  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 527  * @from: Source address, in user space.
 528  * @n:    Number of bytes to copy.
 529  *
 530  * Context: User context only.  This function may sleep.
 531  *
 532  * Copy data from user space to kernel space.  Caller must check
 533  * the specified block with access_ok() before calling this function.
 534  *
 535  * Returns number of bytes that could not be copied.
 536  * On success, this will be zero.
 537  *
 538  * If some data could not be copied, this function will pad the copied
 539  * data to the requested size using zero bytes.
 540  */
 541 #define __copy_from_user(to,from,n)                                     \
 542 ({                                                                      \
 543         void *__cu_to;                                                  \
 544         const void *__cu_from;                                          \
 545         long __cu_len;                                                  \
 546                                                                         \
 547         might_sleep();                                                  \
 548         __cu_to = (to);                                                 \
 549         __cu_from = (from);                                             \
 550         __cu_len = (n);                                                 \
 551         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 552                                            __cu_len);                   \
 553         __cu_len;                                                       \
 554 })
 555
 556 /*
 557  * copy_from_user: - Copy a block of data from user space.
 558  * @to:   Destination address, in kernel space.
 559  * @from: Source address, in user space.
 560  * @n:    Number of bytes to copy.
 561  *
 562  * Context: User context only.  This function may sleep.
 563  *
 564  * Copy data from user space to kernel space.
 565  *
 566  * Returns number of bytes that could not be copied.
 567  * On success, this will be zero.
 568  *
 569  * If some data could not be copied, this function will pad the copied
 570  * data to the requested size using zero bytes.
 571  */
 572 #define copy_from_user(to,from,n)                                       \
 573 ({                                                                      \
 574         void *__cu_to;                                                  \
 575         const void *__cu_from;                                          \
 576         long __cu_len;                                                  \
 577                                                                         \
 578         might_sleep();                                                  \
 579         __cu_to = (to);                                                 \
 580         __cu_from = (from);                                             \
 581         __cu_len = (n);                                                 \
 582         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 583                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 584                                                    __cu_len);           \
 585         __cu_len;                                                       \
 586 })
 587
 588 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 589
 590 #define copy_in_user(to,from,n)                                         \
 591 ({                                                                      \
 592         void *__cu_to;                                                  \
 593         const void *__cu_from;                                          \
 594         long __cu_len;                                                  \
 595                                                                         \
 596         might_sleep();                                                  \
 597         __cu_to = (to);                                                 \
 598         __cu_from = (from);                                             \
 599         __cu_len = (n);                                                 \
 600         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 601                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 602                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 603                                                    __cu_len);           \
 604         __cu_len;                                                       \
 605 })
 606
 607 /*
 608  * __clear_user: - Zero a block of memory in user space, with less checking.
 609  * @to:   Destination address, in user space.
 610  * @n:    Number of bytes to zero.
 611  *
 612  * Zero a block of memory in user space.  Caller must check
 613  * the specified block with access_ok() before calling this function.
 614  *
 615  * Returns number of bytes that could not be cleared.
 616  * On success, this will be zero.
 617  */
 618 static inline __kernel_size_t
 619 __clear_user(void *addr, __kernel_size_t size)
 620 {
 621         __kernel_size_t res;
 622
 623         might_sleep();
 624         __asm__ __volatile__(
 625                 "move\t$4, %1\n\t"
 626                 "move\t$5, $0\n\t"
 627                 "move\t$6, %2\n\t"
 628                 __MODULE_JAL(__bzero)
 629                 "move\t%0, $6"
 630                 : "=r" (res)
 631                 : "r" (addr), "r" (size)
 632                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 633
 634         return res;
 635 }
 636
 637 #define clear_user(addr,n)                                              \
 638 ({                                                                      \
 639         void * __cl_addr = (addr);                                      \
 640         unsigned long __cl_size = (n);                                  \
 641         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 642                 ((unsigned long)(__cl_addr)), __cl_size))               \
 643                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 644         __cl_size;                                                      \
 645 })
 646
 647 /*
 648  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 649  * @dst:   Destination address, in kernel space.  This buffer must be at
 650  *         least @count bytes long.
 651  * @src:   Source address, in user space.
 652  * @count: Maximum number of bytes to copy, including the trailing NUL.
 653  *
 654  * Copies a NUL-terminated string from userspace to kernel space.
 655  * Caller must check the specified block with access_ok() before calling
 656  * this function.
 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 *__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_nocheck_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 /*
 687  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 688  * @dst:   Destination address, in kernel space.  This buffer must be at
 689  *         least @count bytes long.
 690  * @src:   Source address, in user space.
 691  * @count: Maximum number of bytes to copy, including the trailing NUL.
 692  *
 693  * Copies a NUL-terminated string from userspace to kernel space.
 694  *
 695  * On success, returns the length of the string (not including the trailing
 696  * NUL).
 697  *
 698  * If access to userspace fails, returns -EFAULT (some data may have been
 699  * copied).
 700  *
 701  * If @count is smaller than the length of the string, copies @count bytes
 702  * and returns @count.
 703  */
 704 static inline long
 705 strncpy_from_user(char *__to, const char *__from, long __len)
 706 {
 707         long res;
 708
 709         might_sleep();
 710         __asm__ __volatile__(
 711                 "move\t$4, %1\n\t"
 712                 "move\t$5, %2\n\t"
 713                 "move\t$6, %3\n\t"
 714                 __MODULE_JAL(__strncpy_from_user_asm)
 715                 "move\t%0, $2"
 716                 : "=r" (res)
 717                 : "r" (__to), "r" (__from), "r" (__len)
 718                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 719
 720         return res;
 721 }
 722
 723 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 724 static inline long __strlen_user(const char *s)
 725 {
 726         long res;
 727
 728         might_sleep();
 729         __asm__ __volatile__(
 730                 "move\t$4, %1\n\t"
 731                 __MODULE_JAL(__strlen_user_nocheck_asm)
 732                 "move\t%0, $2"
 733                 : "=r" (res)
 734                 : "r" (s)
 735                 : "$2", "$4", __UA_t0, "$31");
 736
 737         return res;
 738 }
 739
 740 /*
 741  * strlen_user: - Get the size of a string in user space.
 742  * @str: The string to measure.
 743  *
 744  * Context: User context only.  This function may sleep.
 745  *
 746  * Get the size of a NUL-terminated string in user space.
 747  *
 748  * Returns the size of the string INCLUDING the terminating NUL.
 749  * On exception, returns 0.
 750  *
 751  * If there is a limit on the length of a valid string, you may wish to
 752  * consider using strnlen_user() instead.
 753  */
 754 static inline long strlen_user(const char *s)
 755 {
 756         long res;
 757
 758         might_sleep();
 759         __asm__ __volatile__(
 760                 "move\t$4, %1\n\t"
 761                 __MODULE_JAL(__strlen_user_asm)
 762                 "move\t%0, $2"
 763                 : "=r" (res)
 764                 : "r" (s)
 765                 : "$2", "$4", __UA_t0, "$31");
 766
 767         return res;
 768 }
 769
 770 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 771 static inline long __strnlen_user(const char *s, long n)
 772 {
 773         long res;
 774
 775         might_sleep();
 776         __asm__ __volatile__(
 777                 "move\t$4, %1\n\t"
 778                 "move\t$5, %2\n\t"
 779                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 780                 "move\t%0, $2"
 781                 : "=r" (res)
 782                 : "r" (s), "r" (n)
 783                 : "$2", "$4", "$5", __UA_t0, "$31");
 784
 785         return res;
 786 }
 787
 788 /*
 789  * strlen_user: - Get the size of a string in user space.
 790  * @str: The string to measure.
 791  *
 792  * Context: User context only.  This function may sleep.
 793  *
 794  * Get the size of a NUL-terminated string in user space.
 795  *
 796  * Returns the size of the string INCLUDING the terminating NUL.
 797  * On exception, returns 0.
 798  *
 799  * If there is a limit on the length of a valid string, you may wish to
 800  * consider using strnlen_user() instead.
 801  */
 802 static inline long strnlen_user(const char *s, long n)
 803 {
 804         long res;
 805
 806         might_sleep();
 807         __asm__ __volatile__(
 808                 "move\t$4, %1\n\t"
 809                 "move\t$5, %2\n\t"
 810                 __MODULE_JAL(__strnlen_user_asm)
 811                 "move\t%0, $2"
 812                 : "=r" (res)
 813                 : "r" (s), "r" (n)
 814                 : "$2", "$4", "$5", __UA_t0, "$31");
 815
 816         return res;
 817 }
 818
 819 struct exception_table_entry
 820 {
 821         unsigned long insn;
 822         unsigned long nextinsn;
 823 };
 824
 825 extern int fixup_exception(struct pt_regs *regs);
 826
 827 #endif /* _ASM_UACCESS_H */