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/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/thread_info.h>
  15 #include <asm-generic/uaccess.h>
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24 #ifdef CONFIG_32BIT
  25
  26 #define __UA_LIMIT      0x80000000UL
  27
  28 #define __UA_ADDR       ".word"
  29 #define __UA_LA         "la"
  30 #define __UA_ADDU       "addu"
  31 #define __UA_t0         "$8"
  32 #define __UA_t1         "$9"
  33
  34 #endif /* CONFIG_32BIT */
  35
  36 #ifdef CONFIG_64BIT
  37
  38 #define __UA_LIMIT      (- TASK_SIZE)
  39
  40 #define __UA_ADDR       ".dword"
  41 #define __UA_LA         "dla"
  42 #define __UA_ADDU       "daddu"
  43 #define __UA_t0         "$12"
  44 #define __UA_t1         "$13"
  45
  46 #endif /* CONFIG_64BIT */
  47
  48 /*
  49  * USER_DS is a bitmask that has the bits set that may not be set in a valid
  50  * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
  51  * the arithmetic we're doing only works if the limit is a power of two, so
  52  * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
  53  * address in this range it's the process's problem, not ours :-)
  54  */
  55
  56 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  57 #define USER_DS         ((mm_segment_t) { __UA_LIMIT })
  58
  59 #define VERIFY_READ    0
  60 #define VERIFY_WRITE   1
  61
  62 #define get_ds()        (KERNEL_DS)
  63 #define get_fs()        (current_thread_info()->addr_limit)
  64 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  65
  66 #define segment_eq(a,b) ((a).seg == (b).seg)
  67
  68
  69 /*
  70  * Is a address valid? This does a straighforward calculation rather
  71  * than tests.
  72  *
  73  * Address valid if:
  74  *  - "addr" doesn't have any high-bits set
  75  *  - AND "size" doesn't have any high-bits set
  76  *  - AND "addr+size" doesn't have any high-bits set
  77  *  - OR we are in kernel mode.
  78  *
  79  * __ua_size() is a trick to avoid runtime checking of positive constant
  80  * sizes; for those we already know at compile time that the size is ok.
  81  */
  82 #define __ua_size(size)                                                 \
  83         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  84
  85 /*
  86  * access_ok: - Checks if a user space pointer is valid
  87  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  88  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  89  *        to write to a block, it is always safe to read from it.
  90  * @addr: User space pointer to start of block to check
  91  * @size: Size of block to check
  92  *
  93  * Context: User context only.  This function may sleep.
  94  *
  95  * Checks if a pointer to a block of memory in user space is valid.
  96  *
  97  * Returns true (nonzero) if the memory block may be valid, false (zero)
  98  * if it is definitely invalid.
  99  *
 100  * Note that, depending on architecture, this function probably just
 101  * checks that the pointer is in the user space range - after calling
 102  * this function, memory access functions may still return -EFAULT.
 103  */
 104
 105 #define __access_mask get_fs().seg
 106
 107 #define __access_ok(addr, size, mask)                                   \
 108         (((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)
 109
 110 #define access_ok(type, addr, size)                                     \
 111         likely(__access_ok((unsigned long)(addr), (size),__access_mask))
 112
 113 /*
 114  * put_user: - Write a simple value into user space.
 115  * @x:   Value to copy to user space.
 116  * @ptr: Destination address, in user space.
 117  *
 118  * Context: User context only.  This function may sleep.
 119  *
 120  * This macro copies a single simple value from kernel space to user
 121  * space.  It supports simple types like char and int, but not larger
 122  * data types like structures or arrays.
 123  *
 124  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 125  * to the result of dereferencing @ptr.
 126  *
 127  * Returns zero on success, or -EFAULT on error.
 128  */
 129 #define put_user(x,ptr) \
 130         __put_user_check((x),(ptr),sizeof(*(ptr)))
 131
 132 /*
 133  * get_user: - Get a simple variable from user space.
 134  * @x:   Variable to store result.
 135  * @ptr: Source address, in user space.
 136  *
 137  * Context: User context only.  This function may sleep.
 138  *
 139  * This macro copies a single simple variable from user space to kernel
 140  * space.  It supports simple types like char and int, but not larger
 141  * data types like structures or arrays.
 142  *
 143  * @ptr must have pointer-to-simple-variable type, and the result of
 144  * dereferencing @ptr must be assignable to @x without a cast.
 145  *
 146  * Returns zero on success, or -EFAULT on error.
 147  * On error, the variable @x is set to zero.
 148  */
 149 #define get_user(x,ptr) \
 150         __get_user_check((x),(ptr),sizeof(*(ptr)))
 151
 152 /*
 153  * __put_user: - Write a simple value into user space, with less checking.
 154  * @x:   Value to copy to user space.
 155  * @ptr: Destination address, in user space.
 156  *
 157  * Context: User context only.  This function may sleep.
 158  *
 159  * This macro copies a single simple value from kernel space to user
 160  * space.  It supports simple types like char and int, but not larger
 161  * data types like structures or arrays.
 162  *
 163  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 164  * to the result of dereferencing @ptr.
 165  *
 166  * Caller must check the pointer with access_ok() before calling this
 167  * function.
 168  *
 169  * Returns zero on success, or -EFAULT on error.
 170  */
 171 #define __put_user(x,ptr) \
 172         __put_user_nocheck((x),(ptr),sizeof(*(ptr)))
 173
 174 /*
 175  * __get_user: - Get a simple variable from user space, with less checking.
 176  * @x:   Variable to store result.
 177  * @ptr: Source address, in user space.
 178  *
 179  * Context: User context only.  This function may sleep.
 180  *
 181  * This macro copies a single simple variable from user space to kernel
 182  * space.  It supports simple types like char and int, but not larger
 183  * data types like structures or arrays.
 184  *
 185  * @ptr must have pointer-to-simple-variable type, and the result of
 186  * dereferencing @ptr must be assignable to @x without a cast.
 187  *
 188  * Caller must check the pointer with access_ok() before calling this
 189  * function.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  * On error, the variable @x is set to zero.
 193  */
 194 #define __get_user(x,ptr) \
 195         __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 196
 197 struct __large_struct { unsigned long buf[100]; };
 198 #define __m(x) (*(struct __large_struct __user *)(x))
 199
 200 /*
 201  * Yuck.  We need two variants, one for 64bit operation and one
 202  * for 32 bit mode and old iron.
 203  */
 204 #ifdef CONFIG_32BIT
 205 #define __GET_USER_DW(val, ptr) __get_user_asm_ll32(val, ptr)
 206 #endif
 207 #ifdef CONFIG_64BIT
 208 #define __GET_USER_DW(val, ptr) __get_user_asm(val, "ld", ptr)
 209 #endif
 210
 211 extern void __get_user_unknown(void);
 212
 213 #define __get_user_common(val, size, ptr)                               \
 214 do {                                                                    \
 215         switch (size) {                                                 \
 216         case 1: __get_user_asm(val, "lb", ptr); break;                  \
 217         case 2: __get_user_asm(val, "lh", ptr); break;                  \
 218         case 4: __get_user_asm(val, "lw", ptr); break;                  \
 219         case 8: __GET_USER_DW(val, ptr); break;                         \
 220         default: __get_user_unknown(); break;                           \
 221         }                                                               \
 222 } while (0)
 223
 224 #define __get_user_nocheck(x,ptr,size)                                  \
 225 ({                                                                      \
 226         long __gu_err;                                                  \
 227                                                                         \
 228         __get_user_common((x), size, ptr);                              \
 229         __gu_err;                                                       \
 230 })
 231
 232 #define __get_user_check(x,ptr,size)                                    \
 233 ({                                                                      \
 234         long __gu_err = -EFAULT;                                        \
 235         const __typeof__(*(ptr)) __user * __gu_ptr = (ptr);             \
 236                                                                         \
 237         if (likely(access_ok(VERIFY_READ,  __gu_ptr, size)))            \
 238                 __get_user_common((x), size, __gu_ptr);                 \
 239                                                                         \
 240         __gu_err;                                                       \
 241 })
 242
 243 #define __get_user_asm(val, insn, addr)                                 \
 244 {                                                                       \
 245         long __gu_tmp;                                                  \
 246                                                                         \
 247         __asm__ __volatile__(                                           \
 248         "1:     " insn "        %1, %3                          \n"     \
 249         "2:                                                     \n"     \
 250         "       .section .fixup,\"ax\"                          \n"     \
 251         "3:     li      %0, %4                                  \n"     \
 252         "       j       2b                                      \n"     \
 253         "       .previous                                       \n"     \
 254         "       .section __ex_table,\"a\"                       \n"     \
 255         "       "__UA_ADDR "\t1b, 3b                            \n"     \
 256         "       .previous                                       \n"     \
 257         : "=r" (__gu_err), "=r" (__gu_tmp)                              \
 258         : "0" (0), "o" (__m(addr)), "i" (-EFAULT));                     \
 259                                                                         \
 260         (val) = (__typeof__(*(addr))) __gu_tmp;                         \
 261 }
 262
 263 /*
 264  * Get a long long 64 using 32 bit registers.
 265  */
 266 #define __get_user_asm_ll32(val, addr)                                  \
 267 {                                                                       \
 268         __asm__ __volatile__(                                           \
 269         "1:     lw      %1, (%3)                                \n"     \
 270         "2:     lw      %D1, 4(%3)                              \n"     \
 271         "       move    %0, $0                                  \n"     \
 272         "3:     .section        .fixup,\"ax\"                   \n"     \
 273         "4:     li      %0, %4                                  \n"     \
 274         "       move    %1, $0                                  \n"     \
 275         "       move    %D1, $0                                 \n"     \
 276         "       j       3b                                      \n"     \
 277         "       .previous                                       \n"     \
 278         "       .section        __ex_table,\"a\"                \n"     \
 279         "       " __UA_ADDR "   1b, 4b                          \n"     \
 280         "       " __UA_ADDR "   2b, 4b                          \n"     \
 281         "       .previous                                       \n"     \
 282         : "=r" (__gu_err), "=&r" (val)                                  \
 283         : "0" (0), "r" (addr), "i" (-EFAULT));                          \
 284 }
 285
 286 /*
 287  * Yuck.  We need two variants, one for 64bit operation and one
 288  * for 32 bit mode and old iron.
 289  */
 290 #ifdef CONFIG_32BIT
 291 #define __PUT_USER_DW(ptr) __put_user_asm_ll32(ptr)
 292 #endif
 293 #ifdef CONFIG_64BIT
 294 #define __PUT_USER_DW(ptr) __put_user_asm("sd", ptr)
 295 #endif
 296
 297 #define __put_user_nocheck(x,ptr,size)                                  \
 298 ({                                                                      \
 299         __typeof__(*(ptr)) __pu_val;                                    \
 300         long __pu_err = 0;                                              \
 301                                                                         \
 302         __pu_val = (x);                                                 \
 303         switch (size) {                                                 \
 304         case 1: __put_user_asm("sb", ptr); break;                       \
 305         case 2: __put_user_asm("sh", ptr); break;                       \
 306         case 4: __put_user_asm("sw", ptr); break;                       \
 307         case 8: __PUT_USER_DW(ptr); break;                              \
 308         default: __put_user_unknown(); break;                           \
 309         }                                                               \
 310         __pu_err;                                                       \
 311 })
 312
 313 #define __put_user_check(x,ptr,size)                                    \
 314 ({                                                                      \
 315         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 316         __typeof__(*(ptr)) __pu_val = (x);                              \
 317         long __pu_err = -EFAULT;                                        \
 318                                                                         \
 319         if (likely(access_ok(VERIFY_WRITE,  __pu_addr, size))) {        \
 320                 switch (size) {                                         \
 321                 case 1: __put_user_asm("sb", __pu_addr); break;         \
 322                 case 2: __put_user_asm("sh", __pu_addr); break;         \
 323                 case 4: __put_user_asm("sw", __pu_addr); break;         \
 324                 case 8: __PUT_USER_DW(__pu_addr); break;                \
 325                 default: __put_user_unknown(); break;                   \
 326                 }                                                       \
 327         }                                                               \
 328         __pu_err;                                                       \
 329 })
 330
 331 #define __put_user_asm(insn, ptr)                                       \
 332 {                                                                       \
 333         __asm__ __volatile__(                                           \
 334         "1:     " insn "        %z2, %3         # __put_user_asm\n"     \
 335         "2:                                                     \n"     \
 336         "       .section        .fixup,\"ax\"                   \n"     \
 337         "3:     li      %0, %4                                  \n"     \
 338         "       j       2b                                      \n"     \
 339         "       .previous                                       \n"     \
 340         "       .section        __ex_table,\"a\"                \n"     \
 341         "       " __UA_ADDR "   1b, 3b                          \n"     \
 342         "       .previous                                       \n"     \
 343         : "=r" (__pu_err)                                               \
 344         : "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),                     \
 345           "i" (-EFAULT));                                               \
 346 }
 347
 348 #define __put_user_asm_ll32(ptr)                                        \
 349 {                                                                       \
 350         __asm__ __volatile__(                                           \
 351         "1:     sw      %2, (%3)        # __put_user_asm_ll32   \n"     \
 352         "2:     sw      %D2, 4(%3)                              \n"     \
 353         "3:                                                     \n"     \
 354         "       .section        .fixup,\"ax\"                   \n"     \
 355         "4:     li      %0, %4                                  \n"     \
 356         "       j       3b                                      \n"     \
 357         "       .previous                                       \n"     \
 358         "       .section        __ex_table,\"a\"                \n"     \
 359         "       " __UA_ADDR "   1b, 4b                          \n"     \
 360         "       " __UA_ADDR "   2b, 4b                          \n"     \
 361         "       .previous"                                              \
 362         : "=r" (__pu_err)                                               \
 363         : "0" (0), "r" (__pu_val), "r" (ptr),                           \
 364           "i" (-EFAULT));                                               \
 365 }
 366
 367 extern void __put_user_unknown(void);
 368
 369 /*
 370  * We're generating jump to subroutines which will be outside the range of
 371  * jump instructions
 372  */
 373 #ifdef MODULE
 374 #define __MODULE_JAL(destination)                                       \
 375         ".set\tnoat\n\t"                                                \
 376         __UA_LA "\t$1, " #destination "\n\t"                            \
 377         "jalr\t$1\n\t"                                                  \
 378         ".set\tat\n\t"
 379 #else
 380 #define __MODULE_JAL(destination)                                       \
 381         "jal\t" #destination "\n\t"
 382 #endif
 383
 384 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 385
 386 #define __invoke_copy_to_user(to,from,n)                                \
 387 ({                                                                      \
 388         register void __user *__cu_to_r __asm__ ("$4");                 \
 389         register const void *__cu_from_r __asm__ ("$5");                \
 390         register long __cu_len_r __asm__ ("$6");                        \
 391                                                                         \
 392         __cu_to_r = (to);                                               \
 393         __cu_from_r = (from);                                           \
 394         __cu_len_r = (n);                                               \
 395         __asm__ __volatile__(                                           \
 396         __MODULE_JAL(__copy_user)                                       \
 397         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 398         :                                                               \
 399         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 400           "memory");                                                    \
 401         __cu_len_r;                                                     \
 402 })
 403
 404 /*
 405  * __copy_to_user: - Copy a block of data into user space, with less checking.
 406  * @to:   Destination address, in user space.
 407  * @from: Source address, in kernel space.
 408  * @n:    Number of bytes to copy.
 409  *
 410  * Context: User context only.  This function may sleep.
 411  *
 412  * Copy data from kernel space to user space.  Caller must check
 413  * the specified block with access_ok() before calling this function.
 414  *
 415  * Returns number of bytes that could not be copied.
 416  * On success, this will be zero.
 417  */
 418 #define __copy_to_user(to,from,n)                                       \
 419 ({                                                                      \
 420         void __user *__cu_to;                                           \
 421         const void *__cu_from;                                          \
 422         long __cu_len;                                                  \
 423                                                                         \
 424         might_sleep();                                                  \
 425         __cu_to = (to);                                                 \
 426         __cu_from = (from);                                             \
 427         __cu_len = (n);                                                 \
 428         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 429         __cu_len;                                                       \
 430 })
 431
 432 #define __copy_to_user_inatomic __copy_to_user
 433 #define __copy_from_user_inatomic __copy_from_user
 434
 435 /*
 436  * copy_to_user: - Copy a block of data into user space.
 437  * @to:   Destination address, in user space.
 438  * @from: Source address, in kernel space.
 439  * @n:    Number of bytes to copy.
 440  *
 441  * Context: User context only.  This function may sleep.
 442  *
 443  * Copy data from kernel space to user space.
 444  *
 445  * Returns number of bytes that could not be copied.
 446  * On success, this will be zero.
 447  */
 448 #define copy_to_user(to,from,n)                                         \
 449 ({                                                                      \
 450         void __user *__cu_to;                                           \
 451         const void *__cu_from;                                          \
 452         long __cu_len;                                                  \
 453                                                                         \
 454         might_sleep();                                                  \
 455         __cu_to = (to);                                                 \
 456         __cu_from = (from);                                             \
 457         __cu_len = (n);                                                 \
 458         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 459                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 460                                                  __cu_len);             \
 461         __cu_len;                                                       \
 462 })
 463
 464 #define __invoke_copy_from_user(to,from,n)                              \
 465 ({                                                                      \
 466         register void *__cu_to_r __asm__ ("$4");                        \
 467         register const void __user *__cu_from_r __asm__ ("$5");         \
 468         register long __cu_len_r __asm__ ("$6");                        \
 469                                                                         \
 470         __cu_to_r = (to);                                               \
 471         __cu_from_r = (from);                                           \
 472         __cu_len_r = (n);                                               \
 473         __asm__ __volatile__(                                           \
 474         ".set\tnoreorder\n\t"                                           \
 475         __MODULE_JAL(__copy_user)                                       \
 476         ".set\tnoat\n\t"                                                \
 477         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 478         ".set\tat\n\t"                                                  \
 479         ".set\treorder"                                                 \
 480         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 481         :                                                               \
 482         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 483           "memory");                                                    \
 484         __cu_len_r;                                                     \
 485 })
 486
 487 /*
 488  * __copy_from_user: - Copy a block of data from user space, with less checking.
 489  * @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 */