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 /*
 467  * copy_to_user: - Copy a block of data into user space.
 468  * @to:   Destination address, in user space.
 469  * @from: Source address, in kernel space.
 470  * @n:    Number of bytes to copy.
 471  *
 472  * Context: User context only.  This function may sleep.
 473  *
 474  * Copy data from kernel space to user space.
 475  *
 476  * Returns number of bytes that could not be copied.
 477  * On success, this will be zero.
 478  */
 479 #define copy_to_user(to,from,n)                                         \
 480 ({                                                                      \
 481         void *__cu_to;                                                  \
 482         const void *__cu_from;                                          \
 483         long __cu_len;                                                  \
 484                                                                         \
 485         might_sleep();                                                  \
 486         __cu_to = (to);                                                 \
 487         __cu_from = (from);                                             \
 488         __cu_len = (n);                                                 \
 489         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 490                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 491                                                  __cu_len);             \
 492         __cu_len;                                                       \
 493 })
 494
 495 #define __invoke_copy_from_user(to,from,n)                              \
 496 ({                                                                      \
 497         register void *__cu_to_r __asm__ ("$4");                        \
 498         register const void *__cu_from_r __asm__ ("$5");                \
 499         register long __cu_len_r __asm__ ("$6");                        \
 500                                                                         \
 501         __cu_to_r = (to);                                               \
 502         __cu_from_r = (from);                                           \
 503         __cu_len_r = (n);                                               \
 504         __asm__ __volatile__(                                           \
 505         ".set\tnoreorder\n\t"                                           \
 506         __MODULE_JAL(__copy_user)                                       \
 507         ".set\tnoat\n\t"                                                \
 508         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 509         ".set\tat\n\t"                                                  \
 510         ".set\treorder\n\t"                                             \
 511         "move\t%0, $6"          /* XXX */                               \
 512         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 513         :                                                               \
 514         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 515           "memory");                                                    \
 516         __cu_len_r;                                                     \
 517 })
 518
 519 /*
 520  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 521  * @from: Source address, in user space.
 522  * @n:    Number of bytes to copy.
 523  *
 524  * Context: User context only.  This function may sleep.
 525  *
 526  * Copy data from user space to kernel space.  Caller must check
 527  * the specified block with access_ok() before calling this function.
 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 *__cu_from;                                          \
 539         long __cu_len;                                                  \
 540                                                                         \
 541         might_sleep();                                                  \
 542         __cu_to = (to);                                                 \
 543         __cu_from = (from);                                             \
 544         __cu_len = (n);                                                 \
 545         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 546                                            __cu_len);                   \
 547         __cu_len;                                                       \
 548 })
 549
 550 /*
 551  * copy_from_user: - Copy a block of data from user space.
 552  * @to:   Destination address, in kernel space.
 553  * @from: Source address, in user space.
 554  * @n:    Number of bytes to copy.
 555  *
 556  * Context: User context only.  This function may sleep.
 557  *
 558  * Copy data from user space to kernel space.
 559  *
 560  * Returns number of bytes that could not be copied.
 561  * On success, this will be zero.
 562  *
 563  * If some data could not be copied, this function will pad the copied
 564  * data to the requested size using zero bytes.
 565  */
 566 #define copy_from_user(to,from,n)                                       \
 567 ({                                                                      \
 568         void *__cu_to;                                                  \
 569         const void *__cu_from;                                          \
 570         long __cu_len;                                                  \
 571                                                                         \
 572         might_sleep();                                                  \
 573         __cu_to = (to);                                                 \
 574         __cu_from = (from);                                             \
 575         __cu_len = (n);                                                 \
 576         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 577                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 578                                                    __cu_len);           \
 579         __cu_len;                                                       \
 580 })
 581
 582 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 583
 584 #define copy_in_user(to,from,n)                                         \
 585 ({                                                                      \
 586         void *__cu_to;                                                  \
 587         const void *__cu_from;                                          \
 588         long __cu_len;                                                  \
 589                                                                         \
 590         might_sleep();                                                  \
 591         __cu_to = (to);                                                 \
 592         __cu_from = (from);                                             \
 593         __cu_len = (n);                                                 \
 594         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 595                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 596                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 597                                                    __cu_len);           \
 598         __cu_len;                                                       \
 599 })
 600
 601 /*
 602  * __clear_user: - Zero a block of memory in user space, with less checking.
 603  * @to:   Destination address, in user space.
 604  * @n:    Number of bytes to zero.
 605  *
 606  * Zero a block of memory in user space.  Caller must check
 607  * the specified block with access_ok() before calling this function.
 608  *
 609  * Returns number of bytes that could not be cleared.
 610  * On success, this will be zero.
 611  */
 612 static inline __kernel_size_t
 613 __clear_user(void *addr, __kernel_size_t size)
 614 {
 615         __kernel_size_t res;
 616
 617         might_sleep();
 618         __asm__ __volatile__(
 619                 "move\t$4, %1\n\t"
 620                 "move\t$5, $0\n\t"
 621                 "move\t$6, %2\n\t"
 622                 __MODULE_JAL(__bzero)
 623                 "move\t%0, $6"
 624                 : "=r" (res)
 625                 : "r" (addr), "r" (size)
 626                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 627
 628         return res;
 629 }
 630
 631 #define clear_user(addr,n)                                              \
 632 ({                                                                      \
 633         void * __cl_addr = (addr);                                      \
 634         unsigned long __cl_size = (n);                                  \
 635         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 636                 ((unsigned long)(__cl_addr)), __cl_size))               \
 637                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 638         __cl_size;                                                      \
 639 })
 640
 641 /*
 642  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 643  * @dst:   Destination address, in kernel space.  This buffer must be at
 644  *         least @count bytes long.
 645  * @src:   Source address, in user space.
 646  * @count: Maximum number of bytes to copy, including the trailing NUL.
 647  *
 648  * Copies a NUL-terminated string from userspace to kernel space.
 649  * Caller must check the specified block with access_ok() before calling
 650  * this function.
 651  *
 652  * On success, returns the length of the string (not including the trailing
 653  * NUL).
 654  *
 655  * If access to userspace fails, returns -EFAULT (some data may have been
 656  * copied).
 657  *
 658  * If @count is smaller than the length of the string, copies @count bytes
 659  * and returns @count.
 660  */
 661 static inline long
 662 __strncpy_from_user(char *__to, const char *__from, long __len)
 663 {
 664         long res;
 665
 666         might_sleep();
 667         __asm__ __volatile__(
 668                 "move\t$4, %1\n\t"
 669                 "move\t$5, %2\n\t"
 670                 "move\t$6, %3\n\t"
 671                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 672                 "move\t%0, $2"
 673                 : "=r" (res)
 674                 : "r" (__to), "r" (__from), "r" (__len)
 675                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 676
 677         return res;
 678 }
 679
 680 /*
 681  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 682  * @dst:   Destination address, in kernel space.  This buffer must be at
 683  *         least @count bytes long.
 684  * @src:   Source address, in user space.
 685  * @count: Maximum number of bytes to copy, including the trailing NUL.
 686  *
 687  * Copies a NUL-terminated string from userspace to kernel space.
 688  *
 689  * On success, returns the length of the string (not including the trailing
 690  * NUL).
 691  *
 692  * If access to userspace fails, returns -EFAULT (some data may have been
 693  * copied).
 694  *
 695  * If @count is smaller than the length of the string, copies @count bytes
 696  * and returns @count.
 697  */
 698 static inline long
 699 strncpy_from_user(char *__to, const char *__from, long __len)
 700 {
 701         long res;
 702
 703         might_sleep();
 704         __asm__ __volatile__(
 705                 "move\t$4, %1\n\t"
 706                 "move\t$5, %2\n\t"
 707                 "move\t$6, %3\n\t"
 708                 __MODULE_JAL(__strncpy_from_user_asm)
 709                 "move\t%0, $2"
 710                 : "=r" (res)
 711                 : "r" (__to), "r" (__from), "r" (__len)
 712                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 713
 714         return res;
 715 }
 716
 717 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 718 static inline long __strlen_user(const char *s)
 719 {
 720         long res;
 721
 722         might_sleep();
 723         __asm__ __volatile__(
 724                 "move\t$4, %1\n\t"
 725                 __MODULE_JAL(__strlen_user_nocheck_asm)
 726                 "move\t%0, $2"
 727                 : "=r" (res)
 728                 : "r" (s)
 729                 : "$2", "$4", __UA_t0, "$31");
 730
 731         return res;
 732 }
 733
 734 /*
 735  * strlen_user: - Get the size of a string in user space.
 736  * @str: The string to measure.
 737  *
 738  * Context: User context only.  This function may sleep.
 739  *
 740  * Get the size of a NUL-terminated string in user space.
 741  *
 742  * Returns the size of the string INCLUDING the terminating NUL.
 743  * On exception, returns 0.
 744  *
 745  * If there is a limit on the length of a valid string, you may wish to
 746  * consider using strnlen_user() instead.
 747  */
 748 static inline long strlen_user(const char *s)
 749 {
 750         long res;
 751
 752         might_sleep();
 753         __asm__ __volatile__(
 754                 "move\t$4, %1\n\t"
 755                 __MODULE_JAL(__strlen_user_asm)
 756                 "move\t%0, $2"
 757                 : "=r" (res)
 758                 : "r" (s)
 759                 : "$2", "$4", __UA_t0, "$31");
 760
 761         return res;
 762 }
 763
 764 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 765 static inline long __strnlen_user(const char *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_nocheck_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 /*
 783  * strlen_user: - Get the size of a string in user space.
 784  * @str: The string to measure.
 785  *
 786  * Context: User context only.  This function may sleep.
 787  *
 788  * Get the size of a NUL-terminated string in user space.
 789  *
 790  * Returns the size of the string INCLUDING the terminating NUL.
 791  * On exception, returns 0.
 792  *
 793  * If there is a limit on the length of a valid string, you may wish to
 794  * consider using strnlen_user() instead.
 795  */
 796 static inline long strnlen_user(const char *s, long n)
 797 {
 798         long res;
 799
 800         might_sleep();
 801         __asm__ __volatile__(
 802                 "move\t$4, %1\n\t"
 803                 "move\t$5, %2\n\t"
 804                 __MODULE_JAL(__strnlen_user_asm)
 805                 "move\t%0, $2"
 806                 : "=r" (res)
 807                 : "r" (s), "r" (n)
 808                 : "$2", "$4", "$5", __UA_t0, "$31");
 809
 810         return res;
 811 }
 812
 813 struct exception_table_entry
 814 {
 815         unsigned long insn;
 816         unsigned long nextinsn;
 817 };
 818
 819 extern int fixup_exception(struct pt_regs *regs);
 820
 821 #endif /* _ASM_UACCESS_H */