include/asm-mips/uaccess.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
   7  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   8  */
   9 #ifndef _ASM_UACCESS_H
  10 #define _ASM_UACCESS_H
  11
  12 #include <linux/config.h>
  13 #include <linux/compiler.h>
  14 #include <linux/errno.h>
  15 #include <linux/thread_info.h>
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  */
  24 #ifdef CONFIG_MIPS32
  25
  26 #define __UA_LIMIT      0x80000000UL
  27
  28 #define __UA_ADDR       ".word"
  29 #define __UA_LA         "la"
  30 #define __UA_ADDU       "addu"
  31 #define __UA_t0         "$8"
  32 #define __UA_t1         "$9"
  33
  34 #endif /* CONFIG_MIPS32 */
  35
  36 #ifdef CONFIG_MIPS64
  37
  38 #define __UA_LIMIT      (- TASK_SIZE)
  39
  40 #define __UA_ADDR       ".dword"
  41 #define __UA_LA         "dla"
  42 #define __UA_ADDU       "daddu"
  43 #define __UA_t0         "$12"
  44 #define __UA_t1         "$13"
  45
  46 #endif /* CONFIG_MIPS64 */
  47
  48 /*
  49  * USER_DS is a bitmask that has the bits set that may not be set in a valid
  50  * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
  51  * the arithmetic we're doing only works if the limit is a power of two, so
  52  * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
  53  * address in this range it's the process's problem, not ours :-)
  54  */
  55
  56 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  57 #define USER_DS         ((mm_segment_t) { __UA_LIMIT })
  58
  59 #define VERIFY_READ    0
  60 #define VERIFY_WRITE   1
  61
  62 #define get_ds()        (KERNEL_DS)
  63 #define get_fs()        (current_thread_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  * verify_area: - Obsolete, use access_ok()
 115  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
 116  * @addr: User space pointer to start of block to check
 117  * @size: Size of block to check
 118  *
 119  * Context: User context only.  This function may sleep.
 120  *
 121  * This function has been replaced by access_ok().
 122  *
 123  * Checks if a pointer to a block of memory in user space is valid.
 124  *
 125  * Returns zero if the memory block may be valid, -EFAULT
 126  * if it is definitely invalid.
 127  *
 128  * See access_ok() for more details.
 129  */
 130 static inline int verify_area(int type, const void * addr, unsigned long size)
 131 {
 132         return access_ok(type, addr, size) ? 0 : -EFAULT;
 133 }
 134
 135 /*
 136  * put_user: - Write a simple value into user space.
 137  * @x:   Value to copy to user space.
 138  * @ptr: Destination address, in user space.
 139  *
 140  * Context: User context only.  This function may sleep.
 141  *
 142  * This macro copies a single simple value from kernel space to user
 143  * space.  It supports simple types like char and int, but not larger
 144  * data types like structures or arrays.
 145  *
 146  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 147  * to the result of dereferencing @ptr.
 148  *
 149  * Returns zero on success, or -EFAULT on error.
 150  */
 151 #define put_user(x,ptr) \
 152         __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 153
 154 /*
 155  * get_user: - Get a simple variable from user space.
 156  * @x:   Variable to store result.
 157  * @ptr: Source address, in user space.
 158  *
 159  * Context: User context only.  This function may sleep.
 160  *
 161  * This macro copies a single simple variable from user space to kernel
 162  * space.  It supports simple types like char and int, but not larger
 163  * data types like structures or arrays.
 164  *
 165  * @ptr must have pointer-to-simple-variable type, and the result of
 166  * dereferencing @ptr must be assignable to @x without a cast.
 167  *
 168  * Returns zero on success, or -EFAULT on error.
 169  * On error, the variable @x is set to zero.
 170  */
 171 #define get_user(x,ptr) \
 172         __get_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 173
 174 /*
 175  * __put_user: - Write a simple value into user space, with less checking.
 176  * @x:   Value to copy to user space.
 177  * @ptr: Destination address, in user space.
 178  *
 179  * Context: User context only.  This function may sleep.
 180  *
 181  * This macro copies a single simple value from kernel space to user
 182  * space.  It supports simple types like char and int, but not larger
 183  * data types like structures or arrays.
 184  *
 185  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 186  * to the result of dereferencing @ptr.
 187  *
 188  * Caller must check the pointer with access_ok() before calling this
 189  * function.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  */
 193 #define __put_user(x,ptr) \
 194         __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 195
 196 /*
 197  * __get_user: - Get a simple variable from user space, with less checking.
 198  * @x:   Variable to store result.
 199  * @ptr: Source address, in user space.
 200  *
 201  * Context: User context only.  This function may sleep.
 202  *
 203  * This macro copies a single simple variable from user space to kernel
 204  * space.  It supports simple types like char and int, but not larger
 205  * data types like structures or arrays.
 206  *
 207  * @ptr must have pointer-to-simple-variable type, and the result of
 208  * dereferencing @ptr must be assignable to @x without a cast.
 209  *
 210  * Caller must check the pointer with access_ok() before calling this
 211  * function.
 212  *
 213  * Returns zero on success, or -EFAULT on error.
 214  * On error, the variable @x is set to zero.
 215  */
 216 #define __get_user(x,ptr) \
 217         __get_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 218
 219 struct __large_struct { unsigned long buf[100]; };
 220 #define __m(x) (*(struct __large_struct *)(x))
 221
 222 /*
 223  * Yuck.  We need two variants, one for 64bit operation and one
 224  * for 32 bit mode and old iron.
 225  */
 226 #ifdef __mips64
 227 #define __GET_USER_DW __get_user_asm("ld")
 228 #else
 229 #define __GET_USER_DW __get_user_asm_ll32
 230 #endif
 231
 232 #define __get_user_nocheck(x,ptr,size)                          \
 233 ({                                                              \
 234         long __gu_err;                                          \
 235         __typeof(*(ptr)) __gu_val;                              \
 236         long __gu_addr;                                         \
 237         might_sleep();                                          \
 238         __asm__("":"=r" (__gu_val));                            \
 239         __gu_addr = (long) (ptr);                               \
 240         __asm__("":"=r" (__gu_err));                            \
 241         switch (size) {                                         \
 242         case 1: __get_user_asm("lb"); break;                    \
 243         case 2: __get_user_asm("lh"); break;                    \
 244         case 4: __get_user_asm("lw"); break;                    \
 245         case 8: __GET_USER_DW; break;                           \
 246         default: __get_user_unknown(); break;                   \
 247         } x = (__typeof__(*(ptr))) __gu_val; __gu_err;          \
 248 })
 249
 250 #define __get_user_check(x,ptr,size)                                    \
 251 ({                                                                      \
 252         long __gu_err;                                                  \
 253         __typeof__(*(ptr)) __gu_val;                                    \
 254         long __gu_addr;                                                 \
 255         might_sleep();                                                  \
 256         __asm__("":"=r" (__gu_val));                                    \
 257         __gu_addr = (long) (ptr);                                       \
 258         __asm__("":"=r" (__gu_err));                                    \
 259         if (access_ok(VERIFY_READ,__gu_addr,size)) {                    \
 260                 switch (size) {                                         \
 261                 case 1: __get_user_asm("lb"); break;                    \
 262                 case 2: __get_user_asm("lh"); break;                    \
 263                 case 4: __get_user_asm("lw"); break;                    \
 264                 case 8: __GET_USER_DW; break;                           \
 265                 default: __get_user_unknown(); break;                   \
 266                 }                                                       \
 267         } x = (__typeof__(*(ptr))) __gu_val; __gu_err;                  \
 268 })
 269
 270 #define __get_user_asm(insn)                                            \
 271 ({                                                                      \
 272         __asm__ __volatile__(                                           \
 273         "1:\t" insn "\t%1,%2\n\t"                                       \
 274         "move\t%0,$0\n"                                                 \
 275         "2:\n\t"                                                        \
 276         ".section\t.fixup,\"ax\"\n"                                     \
 277         "3:\tli\t%0,%3\n\t"                                             \
 278         "move\t%1,$0\n\t"                                               \
 279         "j\t2b\n\t"                                                     \
 280         ".previous\n\t"                                                 \
 281         ".section\t__ex_table,\"a\"\n\t"                                \
 282         __UA_ADDR "\t1b,3b\n\t"                                         \
 283         ".previous"                                                     \
 284         :"=r" (__gu_err), "=r" (__gu_val)                               \
 285         :"o" (__m(__gu_addr)), "i" (-EFAULT));                          \
 286 })
 287
 288 /*
 289  * Get a long long 64 using 32 bit registers.
 290  */
 291 #define __get_user_asm_ll32                                             \
 292 ({                                                                      \
 293         __asm__ __volatile__(                                           \
 294         "1:\tlw\t%1,%2\n"                                               \
 295         "2:\tlw\t%D1,%3\n\t"                                            \
 296         "move\t%0,$0\n"                                                 \
 297         "3:\t.section\t.fixup,\"ax\"\n"                                 \
 298         "4:\tli\t%0,%4\n\t"                                             \
 299         "move\t%1,$0\n\t"                                               \
 300         "move\t%D1,$0\n\t"                                              \
 301         "j\t3b\n\t"                                                     \
 302         ".previous\n\t"                                                 \
 303         ".section\t__ex_table,\"a\"\n\t"                                \
 304         __UA_ADDR "\t1b,4b\n\t"                                         \
 305         __UA_ADDR "\t2b,4b\n\t"                                         \
 306         ".previous"                                                     \
 307         :"=r" (__gu_err), "=&r" (__gu_val)                              \
 308         :"o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)),                \
 309          "i" (-EFAULT));                                                \
 310 })
 311
 312 extern void __get_user_unknown(void);
 313
 314 /*
 315  * Yuck.  We need two variants, one for 64bit operation and one
 316  * for 32 bit mode and old iron.
 317  */
 318 #ifdef __mips64
 319 #define __PUT_USER_DW __put_user_asm("sd")
 320 #else
 321 #define __PUT_USER_DW __put_user_asm_ll32
 322 #endif
 323
 324 #define __put_user_nocheck(x,ptr,size)                                  \
 325 ({                                                                      \
 326         long __pu_err;                                                  \
 327         __typeof__(*(ptr)) __pu_val;                                    \
 328         long __pu_addr;                                                 \
 329         might_sleep();                                                  \
 330         __pu_val = (x);                                                 \
 331         __pu_addr = (long) (ptr);                                       \
 332         __asm__("":"=r" (__pu_err));                                    \
 333         switch (size) {                                                 \
 334         case 1: __put_user_asm("sb"); break;                            \
 335         case 2: __put_user_asm("sh"); break;                            \
 336         case 4: __put_user_asm("sw"); break;                            \
 337         case 8: __PUT_USER_DW; break;                                   \
 338         default: __put_user_unknown(); break;                           \
 339         }                                                               \
 340         __pu_err;                                                       \
 341 })
 342
 343 #define __put_user_check(x,ptr,size)                                    \
 344 ({                                                                      \
 345         long __pu_err;                                                  \
 346         __typeof__(*(ptr)) __pu_val;                                    \
 347         long __pu_addr;                                                 \
 348         might_sleep();                                                  \
 349         __pu_val = (x);                                                 \
 350         __pu_addr = (long) (ptr);                                       \
 351         __asm__("":"=r" (__pu_err));                                    \
 352         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 353                 switch (size) {                                         \
 354                 case 1: __put_user_asm("sb"); break;                    \
 355                 case 2: __put_user_asm("sh"); break;                    \
 356                 case 4: __put_user_asm("sw"); break;                    \
 357                 case 8: __PUT_USER_DW; break;                           \
 358                 default: __put_user_unknown(); break;                   \
 359                 }                                                       \
 360         }                                                               \
 361         __pu_err;                                                       \
 362 })
 363
 364 #define __put_user_asm(insn)                                            \
 365 ({                                                                      \
 366         __asm__ __volatile__(                                           \
 367         "1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t"               \
 368         "move\t%0, $0\n"                                                \
 369         "2:\n\t"                                                        \
 370         ".section\t.fixup,\"ax\"\n"                                     \
 371         "3:\tli\t%0,%3\n\t"                                             \
 372         "j\t2b\n\t"                                                     \
 373         ".previous\n\t"                                                 \
 374         ".section\t__ex_table,\"a\"\n\t"                                \
 375         __UA_ADDR "\t1b,3b\n\t"                                         \
 376         ".previous"                                                     \
 377         :"=r" (__pu_err)                                                \
 378         :"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT));         \
 379 })
 380
 381 #define __put_user_asm_ll32                                             \
 382 ({                                                                      \
 383         __asm__ __volatile__(                                           \
 384         "1:\tsw\t%1, %2\t\t\t# __put_user_asm_ll32\n\t"                 \
 385         "2:\tsw\t%D1, %3\n"                                             \
 386         "move\t%0, $0\n"                                                \
 387         "3:\n\t"                                                        \
 388         ".section\t.fixup,\"ax\"\n"                                     \
 389         "4:\tli\t%0,%4\n\t"                                             \
 390         "j\t3b\n\t"                                                     \
 391         ".previous\n\t"                                                 \
 392         ".section\t__ex_table,\"a\"\n\t"                                \
 393         __UA_ADDR "\t1b,4b\n\t"                                         \
 394         __UA_ADDR "\t2b,4b\n\t"                                         \
 395         ".previous"                                                     \
 396         :"=r" (__pu_err)                                                \
 397         :"r" (__pu_val), "o" (__m(__pu_addr)),                          \
 398          "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                      \
 399 })
 400
 401 extern void __put_user_unknown(void);
 402
 403 /*
 404  * We're generating jump to subroutines which will be outside the range of
 405  * jump instructions
 406  */
 407 #ifdef MODULE
 408 #define __MODULE_JAL(destination)                                       \
 409         ".set\tnoat\n\t"                                                \
 410         __UA_LA "\t$1, " #destination "\n\t"                            \
 411         "jalr\t$1\n\t"                                                  \
 412         ".set\tat\n\t"
 413 #else
 414 #define __MODULE_JAL(destination)                                       \
 415         "jal\t" #destination "\n\t"
 416 #endif
 417
 418 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 419
 420 #define __invoke_copy_to_user(to,from,n)                                \
 421 ({                                                                      \
 422         register void *__cu_to_r __asm__ ("$4");                        \
 423         register const void *__cu_from_r __asm__ ("$5");                \
 424         register long __cu_len_r __asm__ ("$6");                        \
 425                                                                         \
 426         __cu_to_r = (to);                                               \
 427         __cu_from_r = (from);                                           \
 428         __cu_len_r = (n);                                               \
 429         __asm__ __volatile__(                                           \
 430         __MODULE_JAL(__copy_user)                                       \
 431         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 432         :                                                               \
 433         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 434           "memory");                                                    \
 435         __cu_len_r;                                                     \
 436 })
 437
 438 /*
 439  * __copy_to_user: - Copy a block of data into user space, with less checking.
 440  * @to:   Destination address, in user space.
 441  * @from: Source address, in kernel space.
 442  * @n:    Number of bytes to copy.
 443  *
 444  * Context: User context only.  This function may sleep.
 445  *
 446  * Copy data from kernel space to user space.  Caller must check
 447  * the specified block with access_ok() before calling this function.
 448  *
 449  * Returns number of bytes that could not be copied.
 450  * On success, this will be zero.
 451  */
 452 #define __copy_to_user(to,from,n)                                       \
 453 ({                                                                      \
 454         void *__cu_to;                                                  \
 455         const void *__cu_from;                                          \
 456         long __cu_len;                                                  \
 457                                                                         \
 458         might_sleep();                                                  \
 459         __cu_to = (to);                                                 \
 460         __cu_from = (from);                                             \
 461         __cu_len = (n);                                                 \
 462         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 463         __cu_len;                                                       \
 464 })
 465
 466 #define __copy_to_user_inatomic __copy_to_user
 467 #define __copy_from_user_inatomic __copy_from_user
 468
 469 /*
 470  * copy_to_user: - Copy a block of data into user space.
 471  * @to:   Destination address, in user space.
 472  * @from: Source address, in kernel space.
 473  * @n:    Number of bytes to copy.
 474  *
 475  * Context: User context only.  This function may sleep.
 476  *
 477  * Copy data from kernel space to user space.
 478  *
 479  * Returns number of bytes that could not be copied.
 480  * On success, this will be zero.
 481  */
 482 #define copy_to_user(to,from,n)                                         \
 483 ({                                                                      \
 484         void *__cu_to;                                                  \
 485         const void *__cu_from;                                          \
 486         long __cu_len;                                                  \
 487                                                                         \
 488         might_sleep();                                                  \
 489         __cu_to = (to);                                                 \
 490         __cu_from = (from);                                             \
 491         __cu_len = (n);                                                 \
 492         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 493                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 494                                                  __cu_len);             \
 495         __cu_len;                                                       \
 496 })
 497
 498 #define __invoke_copy_from_user(to,from,n)                              \
 499 ({                                                                      \
 500         register void *__cu_to_r __asm__ ("$4");                        \
 501         register const void *__cu_from_r __asm__ ("$5");                \
 502         register long __cu_len_r __asm__ ("$6");                        \
 503                                                                         \
 504         __cu_to_r = (to);                                               \
 505         __cu_from_r = (from);                                           \
 506         __cu_len_r = (n);                                               \
 507         __asm__ __volatile__(                                           \
 508         ".set\tnoreorder\n\t"                                           \
 509         __MODULE_JAL(__copy_user)                                       \
 510         ".set\tnoat\n\t"                                                \
 511         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 512         ".set\tat\n\t"                                                  \
 513         ".set\treorder\n\t"                                             \
 514         "move\t%0, $6"          /* XXX */                               \
 515         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 516         :                                                               \
 517         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 518           "memory");                                                    \
 519         __cu_len_r;                                                     \
 520 })
 521
 522 /*
 523  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 524  * @from: Source address, in user space.
 525  * @n:    Number of bytes to copy.
 526  *
 527  * Context: User context only.  This function may sleep.
 528  *
 529  * Copy data from user space to kernel space.  Caller must check
 530  * the specified block with access_ok() before calling this function.
 531  *
 532  * Returns number of bytes that could not be copied.
 533  * On success, this will be zero.
 534  *
 535  * If some data could not be copied, this function will pad the copied
 536  * data to the requested size using zero bytes.
 537  */
 538 #define __copy_from_user(to,from,n)                                     \
 539 ({                                                                      \
 540         void *__cu_to;                                                  \
 541         const void *__cu_from;                                          \
 542         long __cu_len;                                                  \
 543                                                                         \
 544         might_sleep();                                                  \
 545         __cu_to = (to);                                                 \
 546         __cu_from = (from);                                             \
 547         __cu_len = (n);                                                 \
 548         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 549                                            __cu_len);                   \
 550         __cu_len;                                                       \
 551 })
 552
 553 /*
 554  * copy_from_user: - Copy a block of data from user space.
 555  * @to:   Destination address, in kernel space.
 556  * @from: Source address, in user space.
 557  * @n:    Number of bytes to copy.
 558  *
 559  * Context: User context only.  This function may sleep.
 560  *
 561  * Copy data from user space to kernel space.
 562  *
 563  * Returns number of bytes that could not be copied.
 564  * On success, this will be zero.
 565  *
 566  * If some data could not be copied, this function will pad the copied
 567  * data to the requested size using zero bytes.
 568  */
 569 #define copy_from_user(to,from,n)                                       \
 570 ({                                                                      \
 571         void *__cu_to;                                                  \
 572         const void *__cu_from;                                          \
 573         long __cu_len;                                                  \
 574                                                                         \
 575         might_sleep();                                                  \
 576         __cu_to = (to);                                                 \
 577         __cu_from = (from);                                             \
 578         __cu_len = (n);                                                 \
 579         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 580                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 581                                                    __cu_len);           \
 582         __cu_len;                                                       \
 583 })
 584
 585 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 586
 587 #define copy_in_user(to,from,n)                                         \
 588 ({                                                                      \
 589         void *__cu_to;                                                  \
 590         const void *__cu_from;                                          \
 591         long __cu_len;                                                  \
 592                                                                         \
 593         might_sleep();                                                  \
 594         __cu_to = (to);                                                 \
 595         __cu_from = (from);                                             \
 596         __cu_len = (n);                                                 \
 597         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 598                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 599                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 600                                                    __cu_len);           \
 601         __cu_len;                                                       \
 602 })
 603
 604 /*
 605  * __clear_user: - Zero a block of memory in user space, with less checking.
 606  * @to:   Destination address, in user space.
 607  * @n:    Number of bytes to zero.
 608  *
 609  * Zero a block of memory in user space.  Caller must check
 610  * the specified block with access_ok() before calling this function.
 611  *
 612  * Returns number of bytes that could not be cleared.
 613  * On success, this will be zero.
 614  */
 615 static inline __kernel_size_t
 616 __clear_user(void *addr, __kernel_size_t size)
 617 {
 618         __kernel_size_t res;
 619
 620         might_sleep();
 621         __asm__ __volatile__(
 622                 "move\t$4, %1\n\t"
 623                 "move\t$5, $0\n\t"
 624                 "move\t$6, %2\n\t"
 625                 __MODULE_JAL(__bzero)
 626                 "move\t%0, $6"
 627                 : "=r" (res)
 628                 : "r" (addr), "r" (size)
 629                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 630
 631         return res;
 632 }
 633
 634 #define clear_user(addr,n)                                              \
 635 ({                                                                      \
 636         void * __cl_addr = (addr);                                      \
 637         unsigned long __cl_size = (n);                                  \
 638         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 639                 ((unsigned long)(__cl_addr)), __cl_size))               \
 640                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 641         __cl_size;                                                      \
 642 })
 643
 644 /*
 645  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 646  * @dst:   Destination address, in kernel space.  This buffer must be at
 647  *         least @count bytes long.
 648  * @src:   Source address, in user space.
 649  * @count: Maximum number of bytes to copy, including the trailing NUL.
 650  *
 651  * Copies a NUL-terminated string from userspace to kernel space.
 652  * Caller must check the specified block with access_ok() before calling
 653  * this function.
 654  *
 655  * On success, returns the length of the string (not including the trailing
 656  * NUL).
 657  *
 658  * If access to userspace fails, returns -EFAULT (some data may have been
 659  * copied).
 660  *
 661  * If @count is smaller than the length of the string, copies @count bytes
 662  * and returns @count.
 663  */
 664 static inline long
 665 __strncpy_from_user(char *__to, const char *__from, long __len)
 666 {
 667         long res;
 668
 669         might_sleep();
 670         __asm__ __volatile__(
 671                 "move\t$4, %1\n\t"
 672                 "move\t$5, %2\n\t"
 673                 "move\t$6, %3\n\t"
 674                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 675                 "move\t%0, $2"
 676                 : "=r" (res)
 677                 : "r" (__to), "r" (__from), "r" (__len)
 678                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 679
 680         return res;
 681 }
 682
 683 /*
 684  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 685  * @dst:   Destination address, in kernel space.  This buffer must be at
 686  *         least @count bytes long.
 687  * @src:   Source address, in user space.
 688  * @count: Maximum number of bytes to copy, including the trailing NUL.
 689  *
 690  * Copies a NUL-terminated string from userspace to kernel space.
 691  *
 692  * On success, returns the length of the string (not including the trailing
 693  * NUL).
 694  *
 695  * If access to userspace fails, returns -EFAULT (some data may have been
 696  * copied).
 697  *
 698  * If @count is smaller than the length of the string, copies @count bytes
 699  * and returns @count.
 700  */
 701 static inline long
 702 strncpy_from_user(char *__to, const char *__from, long __len)
 703 {
 704         long res;
 705
 706         might_sleep();
 707         __asm__ __volatile__(
 708                 "move\t$4, %1\n\t"
 709                 "move\t$5, %2\n\t"
 710                 "move\t$6, %3\n\t"
 711                 __MODULE_JAL(__strncpy_from_user_asm)
 712                 "move\t%0, $2"
 713                 : "=r" (res)
 714                 : "r" (__to), "r" (__from), "r" (__len)
 715                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 716
 717         return res;
 718 }
 719
 720 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 721 static inline long __strlen_user(const char *s)
 722 {
 723         long res;
 724
 725         might_sleep();
 726         __asm__ __volatile__(
 727                 "move\t$4, %1\n\t"
 728                 __MODULE_JAL(__strlen_user_nocheck_asm)
 729                 "move\t%0, $2"
 730                 : "=r" (res)
 731                 : "r" (s)
 732                 : "$2", "$4", __UA_t0, "$31");
 733
 734         return res;
 735 }
 736
 737 /*
 738  * strlen_user: - Get the size of a string in user space.
 739  * @str: The string to measure.
 740  *
 741  * Context: User context only.  This function may sleep.
 742  *
 743  * Get the size of a NUL-terminated string in user space.
 744  *
 745  * Returns the size of the string INCLUDING the terminating NUL.
 746  * On exception, returns 0.
 747  *
 748  * If there is a limit on the length of a valid string, you may wish to
 749  * consider using strnlen_user() instead.
 750  */
 751 static inline long strlen_user(const char *s)
 752 {
 753         long res;
 754
 755         might_sleep();
 756         __asm__ __volatile__(
 757                 "move\t$4, %1\n\t"
 758                 __MODULE_JAL(__strlen_user_asm)
 759                 "move\t%0, $2"
 760                 : "=r" (res)
 761                 : "r" (s)
 762                 : "$2", "$4", __UA_t0, "$31");
 763
 764         return res;
 765 }
 766
 767 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 768 static inline long __strnlen_user(const char *s, long n)
 769 {
 770         long res;
 771
 772         might_sleep();
 773         __asm__ __volatile__(
 774                 "move\t$4, %1\n\t"
 775                 "move\t$5, %2\n\t"
 776                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 777                 "move\t%0, $2"
 778                 : "=r" (res)
 779                 : "r" (s), "r" (n)
 780                 : "$2", "$4", "$5", __UA_t0, "$31");
 781
 782         return res;
 783 }
 784
 785 /*
 786  * strlen_user: - Get the size of a string in user space.
 787  * @str: The string to measure.
 788  *
 789  * Context: User context only.  This function may sleep.
 790  *
 791  * Get the size of a NUL-terminated string in user space.
 792  *
 793  * Returns the size of the string INCLUDING the terminating NUL.
 794  * On exception, returns 0.
 795  *
 796  * If there is a limit on the length of a valid string, you may wish to
 797  * consider using strnlen_user() instead.
 798  */
 799 static inline long strnlen_user(const char *s, long n)
 800 {
 801         long res;
 802
 803         might_sleep();
 804         __asm__ __volatile__(
 805                 "move\t$4, %1\n\t"
 806                 "move\t$5, %2\n\t"
 807                 __MODULE_JAL(__strnlen_user_asm)
 808                 "move\t%0, $2"
 809                 : "=r" (res)
 810                 : "r" (s), "r" (n)
 811                 : "$2", "$4", "$5", __UA_t0, "$31");
 812
 813         return res;
 814 }
 815
 816 struct exception_table_entry
 817 {
 818         unsigned long insn;
 819         unsigned long nextinsn;
 820 };
 821
 822 extern int fixup_exception(struct pt_regs *regs);
 823
 824 #endif /* _ASM_UACCESS_H */