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 #include <asm-generic/uaccess.h>
  17
  18 /*
  19  * The fs value determines whether argument validity checking should be
  20  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  21  * get_fs() == KERNEL_DS, checking is bypassed.
  22  *
  23  * For historical reasons, these macros are grossly misnamed.
  24  */
  25 #ifdef CONFIG_MIPS32
  26
  27 #define __UA_LIMIT      0x80000000UL
  28
  29 #define __UA_ADDR       ".word"
  30 #define __UA_LA         "la"
  31 #define __UA_ADDU       "addu"
  32 #define __UA_t0         "$8"
  33 #define __UA_t1         "$9"
  34
  35 #endif /* CONFIG_MIPS32 */
  36
  37 #ifdef CONFIG_MIPS64
  38
  39 #define __UA_LIMIT      (- TASK_SIZE)
  40
  41 #define __UA_ADDR       ".dword"
  42 #define __UA_LA         "dla"
  43 #define __UA_ADDU       "daddu"
  44 #define __UA_t0         "$12"
  45 #define __UA_t1         "$13"
  46
  47 #endif /* CONFIG_MIPS64 */
  48
  49 /*
  50  * USER_DS is a bitmask that has the bits set that may not be set in a valid
  51  * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
  52  * the arithmetic we're doing only works if the limit is a power of two, so
  53  * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
  54  * address in this range it's the process's problem, not ours :-)
  55  */
  56
  57 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  58 #define USER_DS         ((mm_segment_t) { __UA_LIMIT })
  59
  60 #define VERIFY_READ    0
  61 #define VERIFY_WRITE   1
  62
  63 #define get_ds()        (KERNEL_DS)
  64 #define get_fs()        (current_thread_info()->addr_limit)
  65 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  66
  67 #define segment_eq(a,b) ((a).seg == (b).seg)
  68
  69
  70 /*
  71  * Is a address valid? This does a straighforward calculation rather
  72  * than tests.
  73  *
  74  * Address valid if:
  75  *  - "addr" doesn't have any high-bits set
  76  *  - AND "size" doesn't have any high-bits set
  77  *  - AND "addr+size" doesn't have any high-bits set
  78  *  - OR we are in kernel mode.
  79  *
  80  * __ua_size() is a trick to avoid runtime checking of positive constant
  81  * sizes; for those we already know at compile time that the size is ok.
  82  */
  83 #define __ua_size(size)                                                 \
  84         ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
  85
  86 /*
  87  * access_ok: - Checks if a user space pointer is valid
  88  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  89  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  90  *        to write to a block, it is always safe to read from it.
  91  * @addr: User space pointer to start of block to check
  92  * @size: Size of block to check
  93  *
  94  * Context: User context only.  This function may sleep.
  95  *
  96  * Checks if a pointer to a block of memory in user space is valid.
  97  *
  98  * Returns true (nonzero) if the memory block may be valid, false (zero)
  99  * if it is definitely invalid.
 100  *
 101  * Note that, depending on architecture, this function probably just
 102  * checks that the pointer is in the user space range - after calling
 103  * this function, memory access functions may still return -EFAULT.
 104  */
 105
 106 #define __access_mask get_fs().seg
 107
 108 #define __access_ok(addr, size, mask)                                   \
 109         (((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)
 110
 111 #define access_ok(type, addr, size)                                     \
 112         likely(__access_ok((unsigned long)(addr), (size),__access_mask))
 113
 114 /*
 115  * verify_area: - Obsolete, use access_ok()
 116  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
 117  * @addr: User space pointer to start of block to check
 118  * @size: Size of block to check
 119  *
 120  * Context: User context only.  This function may sleep.
 121  *
 122  * This function has been replaced by access_ok().
 123  *
 124  * Checks if a pointer to a block of memory in user space is valid.
 125  *
 126  * Returns zero if the memory block may be valid, -EFAULT
 127  * if it is definitely invalid.
 128  *
 129  * See access_ok() for more details.
 130  */
 131 static inline int verify_area(int type, const void * addr, unsigned long size)
 132 {
 133         return access_ok(type, addr, size) ? 0 : -EFAULT;
 134 }
 135
 136 /*
 137  * put_user: - Write a simple value into user space.
 138  * @x:   Value to copy to user space.
 139  * @ptr: Destination address, in user space.
 140  *
 141  * Context: User context only.  This function may sleep.
 142  *
 143  * This macro copies a single simple value from kernel space to user
 144  * space.  It supports simple types like char and int, but not larger
 145  * data types like structures or arrays.
 146  *
 147  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 148  * to the result of dereferencing @ptr.
 149  *
 150  * Returns zero on success, or -EFAULT on error.
 151  */
 152 #define put_user(x,ptr) \
 153         __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 154
 155 /*
 156  * get_user: - Get a simple variable from user space.
 157  * @x:   Variable to store result.
 158  * @ptr: Source address, in user space.
 159  *
 160  * Context: User context only.  This function may sleep.
 161  *
 162  * This macro copies a single simple variable from user space to kernel
 163  * space.  It supports simple types like char and int, but not larger
 164  * data types like structures or arrays.
 165  *
 166  * @ptr must have pointer-to-simple-variable type, and the result of
 167  * dereferencing @ptr must be assignable to @x without a cast.
 168  *
 169  * Returns zero on success, or -EFAULT on error.
 170  * On error, the variable @x is set to zero.
 171  */
 172 #define get_user(x,ptr) \
 173         __get_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 174
 175 /*
 176  * __put_user: - Write a simple value into user space, with less checking.
 177  * @x:   Value to copy to user space.
 178  * @ptr: Destination address, in user space.
 179  *
 180  * Context: User context only.  This function may sleep.
 181  *
 182  * This macro copies a single simple value from kernel space to user
 183  * space.  It supports simple types like char and int, but not larger
 184  * data types like structures or arrays.
 185  *
 186  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 187  * to the result of dereferencing @ptr.
 188  *
 189  * Caller must check the pointer with access_ok() before calling this
 190  * function.
 191  *
 192  * Returns zero on success, or -EFAULT on error.
 193  */
 194 #define __put_user(x,ptr) \
 195         __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 196
 197 /*
 198  * __get_user: - Get a simple variable from user space, with less checking.
 199  * @x:   Variable to store result.
 200  * @ptr: Source address, in user space.
 201  *
 202  * Context: User context only.  This function may sleep.
 203  *
 204  * This macro copies a single simple variable from user space to kernel
 205  * space.  It supports simple types like char and int, but not larger
 206  * data types like structures or arrays.
 207  *
 208  * @ptr must have pointer-to-simple-variable type, and the result of
 209  * dereferencing @ptr must be assignable to @x without a cast.
 210  *
 211  * Caller must check the pointer with access_ok() before calling this
 212  * function.
 213  *
 214  * Returns zero on success, or -EFAULT on error.
 215  * On error, the variable @x is set to zero.
 216  */
 217 #define __get_user(x,ptr) \
 218         __get_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 219
 220 struct __large_struct { unsigned long buf[100]; };
 221 #define __m(x) (*(struct __large_struct *)(x))
 222
 223 /*
 224  * Yuck.  We need two variants, one for 64bit operation and one
 225  * for 32 bit mode and old iron.
 226  */
 227 #ifdef __mips64
 228 #define __GET_USER_DW __get_user_asm("ld")
 229 #else
 230 #define __GET_USER_DW __get_user_asm_ll32
 231 #endif
 232
 233 #define __get_user_nocheck(x,ptr,size)                          \
 234 ({                                                              \
 235         long __gu_err;                                          \
 236         __typeof(*(ptr)) __gu_val;                              \
 237         long __gu_addr;                                         \
 238         might_sleep();                                          \
 239         __asm__("":"=r" (__gu_val));                            \
 240         __gu_addr = (long) (ptr);                               \
 241         __asm__("":"=r" (__gu_err));                            \
 242         switch (size) {                                         \
 243         case 1: __get_user_asm("lb"); break;                    \
 244         case 2: __get_user_asm("lh"); break;                    \
 245         case 4: __get_user_asm("lw"); break;                    \
 246         case 8: __GET_USER_DW; break;                           \
 247         default: __get_user_unknown(); break;                   \
 248         } x = (__typeof__(*(ptr))) __gu_val; __gu_err;          \
 249 })
 250
 251 #define __get_user_check(x,ptr,size)                                    \
 252 ({                                                                      \
 253         long __gu_err;                                                  \
 254         __typeof__(*(ptr)) __gu_val;                                    \
 255         long __gu_addr;                                                 \
 256         might_sleep();                                                  \
 257         __asm__("":"=r" (__gu_val));                                    \
 258         __gu_addr = (long) (ptr);                                       \
 259         __asm__("":"=r" (__gu_err));                                    \
 260         if (access_ok(VERIFY_READ,__gu_addr,size)) {                    \
 261                 switch (size) {                                         \
 262                 case 1: __get_user_asm("lb"); break;                    \
 263                 case 2: __get_user_asm("lh"); break;                    \
 264                 case 4: __get_user_asm("lw"); break;                    \
 265                 case 8: __GET_USER_DW; break;                           \
 266                 default: __get_user_unknown(); break;                   \
 267                 }                                                       \
 268         } x = (__typeof__(*(ptr))) __gu_val; __gu_err;                  \
 269 })
 270
 271 #define __get_user_asm(insn)                                            \
 272 ({                                                                      \
 273         __asm__ __volatile__(                                           \
 274         "1:\t" insn "\t%1,%2\n\t"                                       \
 275         "move\t%0,$0\n"                                                 \
 276         "2:\n\t"                                                        \
 277         ".section\t.fixup,\"ax\"\n"                                     \
 278         "3:\tli\t%0,%3\n\t"                                             \
 279         "move\t%1,$0\n\t"                                               \
 280         "j\t2b\n\t"                                                     \
 281         ".previous\n\t"                                                 \
 282         ".section\t__ex_table,\"a\"\n\t"                                \
 283         __UA_ADDR "\t1b,3b\n\t"                                         \
 284         ".previous"                                                     \
 285         :"=r" (__gu_err), "=r" (__gu_val)                               \
 286         :"o" (__m(__gu_addr)), "i" (-EFAULT));                          \
 287 })
 288
 289 /*
 290  * Get a long long 64 using 32 bit registers.
 291  */
 292 #define __get_user_asm_ll32                                             \
 293 ({                                                                      \
 294         __asm__ __volatile__(                                           \
 295         "1:\tlw\t%1,%2\n"                                               \
 296         "2:\tlw\t%D1,%3\n\t"                                            \
 297         "move\t%0,$0\n"                                                 \
 298         "3:\t.section\t.fixup,\"ax\"\n"                                 \
 299         "4:\tli\t%0,%4\n\t"                                             \
 300         "move\t%1,$0\n\t"                                               \
 301         "move\t%D1,$0\n\t"                                              \
 302         "j\t3b\n\t"                                                     \
 303         ".previous\n\t"                                                 \
 304         ".section\t__ex_table,\"a\"\n\t"                                \
 305         __UA_ADDR "\t1b,4b\n\t"                                         \
 306         __UA_ADDR "\t2b,4b\n\t"                                         \
 307         ".previous"                                                     \
 308         :"=r" (__gu_err), "=&r" (__gu_val)                              \
 309         :"o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)),                \
 310          "i" (-EFAULT));                                                \
 311 })
 312
 313 extern void __get_user_unknown(void);
 314
 315 /*
 316  * Yuck.  We need two variants, one for 64bit operation and one
 317  * for 32 bit mode and old iron.
 318  */
 319 #ifdef __mips64
 320 #define __PUT_USER_DW __put_user_asm("sd")
 321 #else
 322 #define __PUT_USER_DW __put_user_asm_ll32
 323 #endif
 324
 325 #define __put_user_nocheck(x,ptr,size)                                  \
 326 ({                                                                      \
 327         long __pu_err;                                                  \
 328         __typeof__(*(ptr)) __pu_val;                                    \
 329         long __pu_addr;                                                 \
 330         might_sleep();                                                  \
 331         __pu_val = (x);                                                 \
 332         __pu_addr = (long) (ptr);                                       \
 333         __asm__("":"=r" (__pu_err));                                    \
 334         switch (size) {                                                 \
 335         case 1: __put_user_asm("sb"); break;                            \
 336         case 2: __put_user_asm("sh"); break;                            \
 337         case 4: __put_user_asm("sw"); break;                            \
 338         case 8: __PUT_USER_DW; break;                                   \
 339         default: __put_user_unknown(); break;                           \
 340         }                                                               \
 341         __pu_err;                                                       \
 342 })
 343
 344 #define __put_user_check(x,ptr,size)                                    \
 345 ({                                                                      \
 346         long __pu_err;                                                  \
 347         __typeof__(*(ptr)) __pu_val;                                    \
 348         long __pu_addr;                                                 \
 349         might_sleep();                                                  \
 350         __pu_val = (x);                                                 \
 351         __pu_addr = (long) (ptr);                                       \
 352         __asm__("":"=r" (__pu_err));                                    \
 353         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 354                 switch (size) {                                         \
 355                 case 1: __put_user_asm("sb"); break;                    \
 356                 case 2: __put_user_asm("sh"); break;                    \
 357                 case 4: __put_user_asm("sw"); break;                    \
 358                 case 8: __PUT_USER_DW; break;                           \
 359                 default: __put_user_unknown(); break;                   \
 360                 }                                                       \
 361         }                                                               \
 362         __pu_err;                                                       \
 363 })
 364
 365 #define __put_user_asm(insn)                                            \
 366 ({                                                                      \
 367         __asm__ __volatile__(                                           \
 368         "1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t"               \
 369         "move\t%0, $0\n"                                                \
 370         "2:\n\t"                                                        \
 371         ".section\t.fixup,\"ax\"\n"                                     \
 372         "3:\tli\t%0,%3\n\t"                                             \
 373         "j\t2b\n\t"                                                     \
 374         ".previous\n\t"                                                 \
 375         ".section\t__ex_table,\"a\"\n\t"                                \
 376         __UA_ADDR "\t1b,3b\n\t"                                         \
 377         ".previous"                                                     \
 378         :"=r" (__pu_err)                                                \
 379         :"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT));         \
 380 })
 381
 382 #define __put_user_asm_ll32                                             \
 383 ({                                                                      \
 384         __asm__ __volatile__(                                           \
 385         "1:\tsw\t%1, %2\t\t\t# __put_user_asm_ll32\n\t"                 \
 386         "2:\tsw\t%D1, %3\n"                                             \
 387         "move\t%0, $0\n"                                                \
 388         "3:\n\t"                                                        \
 389         ".section\t.fixup,\"ax\"\n"                                     \
 390         "4:\tli\t%0,%4\n\t"                                             \
 391         "j\t3b\n\t"                                                     \
 392         ".previous\n\t"                                                 \
 393         ".section\t__ex_table,\"a\"\n\t"                                \
 394         __UA_ADDR "\t1b,4b\n\t"                                         \
 395         __UA_ADDR "\t2b,4b\n\t"                                         \
 396         ".previous"                                                     \
 397         :"=r" (__pu_err)                                                \
 398         :"r" (__pu_val), "o" (__m(__pu_addr)),                          \
 399          "o" (__m(__pu_addr + 4)), "i" (-EFAULT));                      \
 400 })
 401
 402 extern void __put_user_unknown(void);
 403
 404 /*
 405  * We're generating jump to subroutines which will be outside the range of
 406  * jump instructions
 407  */
 408 #ifdef MODULE
 409 #define __MODULE_JAL(destination)                                       \
 410         ".set\tnoat\n\t"                                                \
 411         __UA_LA "\t$1, " #destination "\n\t"                            \
 412         "jalr\t$1\n\t"                                                  \
 413         ".set\tat\n\t"
 414 #else
 415 #define __MODULE_JAL(destination)                                       \
 416         "jal\t" #destination "\n\t"
 417 #endif
 418
 419 extern size_t __copy_user(void *__to, const void *__from, size_t __n);
 420
 421 #define __invoke_copy_to_user(to,from,n)                                \
 422 ({                                                                      \
 423         register void *__cu_to_r __asm__ ("$4");                        \
 424         register const void *__cu_from_r __asm__ ("$5");                \
 425         register long __cu_len_r __asm__ ("$6");                        \
 426                                                                         \
 427         __cu_to_r = (to);                                               \
 428         __cu_from_r = (from);                                           \
 429         __cu_len_r = (n);                                               \
 430         __asm__ __volatile__(                                           \
 431         __MODULE_JAL(__copy_user)                                       \
 432         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 433         :                                                               \
 434         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 435           "memory");                                                    \
 436         __cu_len_r;                                                     \
 437 })
 438
 439 /*
 440  * __copy_to_user: - Copy a block of data into user space, with less checking.
 441  * @to:   Destination address, in user space.
 442  * @from: Source address, in kernel space.
 443  * @n:    Number of bytes to copy.
 444  *
 445  * Context: User context only.  This function may sleep.
 446  *
 447  * Copy data from kernel space to user space.  Caller must check
 448  * the specified block with access_ok() before calling this function.
 449  *
 450  * Returns number of bytes that could not be copied.
 451  * On success, this will be zero.
 452  */
 453 #define __copy_to_user(to,from,n)                                       \
 454 ({                                                                      \
 455         void *__cu_to;                                                  \
 456         const void *__cu_from;                                          \
 457         long __cu_len;                                                  \
 458                                                                         \
 459         might_sleep();                                                  \
 460         __cu_to = (to);                                                 \
 461         __cu_from = (from);                                             \
 462         __cu_len = (n);                                                 \
 463         __cu_len = __invoke_copy_to_user(__cu_to, __cu_from, __cu_len); \
 464         __cu_len;                                                       \
 465 })
 466
 467 #define __copy_to_user_inatomic __copy_to_user
 468 #define __copy_from_user_inatomic __copy_from_user
 469
 470 /*
 471  * copy_to_user: - Copy a block of data into user space.
 472  * @to:   Destination address, in user space.
 473  * @from: Source address, in kernel space.
 474  * @n:    Number of bytes to copy.
 475  *
 476  * Context: User context only.  This function may sleep.
 477  *
 478  * Copy data from kernel space to user space.
 479  *
 480  * Returns number of bytes that could not be copied.
 481  * On success, this will be zero.
 482  */
 483 #define copy_to_user(to,from,n)                                         \
 484 ({                                                                      \
 485         void *__cu_to;                                                  \
 486         const void *__cu_from;                                          \
 487         long __cu_len;                                                  \
 488                                                                         \
 489         might_sleep();                                                  \
 490         __cu_to = (to);                                                 \
 491         __cu_from = (from);                                             \
 492         __cu_len = (n);                                                 \
 493         if (access_ok(VERIFY_WRITE, __cu_to, __cu_len))                 \
 494                 __cu_len = __invoke_copy_to_user(__cu_to, __cu_from,    \
 495                                                  __cu_len);             \
 496         __cu_len;                                                       \
 497 })
 498
 499 #define __invoke_copy_from_user(to,from,n)                              \
 500 ({                                                                      \
 501         register void *__cu_to_r __asm__ ("$4");                        \
 502         register const void *__cu_from_r __asm__ ("$5");                \
 503         register long __cu_len_r __asm__ ("$6");                        \
 504                                                                         \
 505         __cu_to_r = (to);                                               \
 506         __cu_from_r = (from);                                           \
 507         __cu_len_r = (n);                                               \
 508         __asm__ __volatile__(                                           \
 509         ".set\tnoreorder\n\t"                                           \
 510         __MODULE_JAL(__copy_user)                                       \
 511         ".set\tnoat\n\t"                                                \
 512         __UA_ADDU "\t$1, %1, %2\n\t"                                    \
 513         ".set\tat\n\t"                                                  \
 514         ".set\treorder\n\t"                                             \
 515         "move\t%0, $6"          /* XXX */                               \
 516         : "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)       \
 517         :                                                               \
 518         : "$8", "$9", "$10", "$11", "$12", "$15", "$24", "$31",         \
 519           "memory");                                                    \
 520         __cu_len_r;                                                     \
 521 })
 522
 523 /*
 524  * __copy_from_user: - Copy a block of data from user space, with less checking. * @to:   Destination address, in kernel space.
 525  * @from: Source address, in user space.
 526  * @n:    Number of bytes to copy.
 527  *
 528  * Context: User context only.  This function may sleep.
 529  *
 530  * Copy data from user space to kernel space.  Caller must check
 531  * the specified block with access_ok() before calling this function.
 532  *
 533  * Returns number of bytes that could not be copied.
 534  * On success, this will be zero.
 535  *
 536  * If some data could not be copied, this function will pad the copied
 537  * data to the requested size using zero bytes.
 538  */
 539 #define __copy_from_user(to,from,n)                                     \
 540 ({                                                                      \
 541         void *__cu_to;                                                  \
 542         const void *__cu_from;                                          \
 543         long __cu_len;                                                  \
 544                                                                         \
 545         might_sleep();                                                  \
 546         __cu_to = (to);                                                 \
 547         __cu_from = (from);                                             \
 548         __cu_len = (n);                                                 \
 549         __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,          \
 550                                            __cu_len);                   \
 551         __cu_len;                                                       \
 552 })
 553
 554 /*
 555  * copy_from_user: - Copy a block of data from user space.
 556  * @to:   Destination address, in kernel space.
 557  * @from: Source address, in user space.
 558  * @n:    Number of bytes to copy.
 559  *
 560  * Context: User context only.  This function may sleep.
 561  *
 562  * Copy data from user space to kernel space.
 563  *
 564  * Returns number of bytes that could not be copied.
 565  * On success, this will be zero.
 566  *
 567  * If some data could not be copied, this function will pad the copied
 568  * data to the requested size using zero bytes.
 569  */
 570 #define copy_from_user(to,from,n)                                       \
 571 ({                                                                      \
 572         void *__cu_to;                                                  \
 573         const void *__cu_from;                                          \
 574         long __cu_len;                                                  \
 575                                                                         \
 576         might_sleep();                                                  \
 577         __cu_to = (to);                                                 \
 578         __cu_from = (from);                                             \
 579         __cu_len = (n);                                                 \
 580         if (access_ok(VERIFY_READ, __cu_from, __cu_len))                \
 581                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 582                                                    __cu_len);           \
 583         __cu_len;                                                       \
 584 })
 585
 586 #define __copy_in_user(to, from, n)     __copy_from_user(to, from, n)
 587
 588 #define copy_in_user(to,from,n)                                         \
 589 ({                                                                      \
 590         void *__cu_to;                                                  \
 591         const void *__cu_from;                                          \
 592         long __cu_len;                                                  \
 593                                                                         \
 594         might_sleep();                                                  \
 595         __cu_to = (to);                                                 \
 596         __cu_from = (from);                                             \
 597         __cu_len = (n);                                                 \
 598         if (likely(access_ok(VERIFY_READ, __cu_from, __cu_len) &&       \
 599                    access_ok(VERIFY_WRITE, __cu_to, __cu_len)))         \
 600                 __cu_len = __invoke_copy_from_user(__cu_to, __cu_from,  \
 601                                                    __cu_len);           \
 602         __cu_len;                                                       \
 603 })
 604
 605 /*
 606  * __clear_user: - Zero a block of memory in user space, with less checking.
 607  * @to:   Destination address, in user space.
 608  * @n:    Number of bytes to zero.
 609  *
 610  * Zero a block of memory in user space.  Caller must check
 611  * the specified block with access_ok() before calling this function.
 612  *
 613  * Returns number of bytes that could not be cleared.
 614  * On success, this will be zero.
 615  */
 616 static inline __kernel_size_t
 617 __clear_user(void *addr, __kernel_size_t size)
 618 {
 619         __kernel_size_t res;
 620
 621         might_sleep();
 622         __asm__ __volatile__(
 623                 "move\t$4, %1\n\t"
 624                 "move\t$5, $0\n\t"
 625                 "move\t$6, %2\n\t"
 626                 __MODULE_JAL(__bzero)
 627                 "move\t%0, $6"
 628                 : "=r" (res)
 629                 : "r" (addr), "r" (size)
 630                 : "$4", "$5", "$6", __UA_t0, __UA_t1, "$31");
 631
 632         return res;
 633 }
 634
 635 #define clear_user(addr,n)                                              \
 636 ({                                                                      \
 637         void * __cl_addr = (addr);                                      \
 638         unsigned long __cl_size = (n);                                  \
 639         if (__cl_size && access_ok(VERIFY_WRITE,                        \
 640                 ((unsigned long)(__cl_addr)), __cl_size))               \
 641                 __cl_size = __clear_user(__cl_addr, __cl_size);         \
 642         __cl_size;                                                      \
 643 })
 644
 645 /*
 646  * __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
 647  * @dst:   Destination address, in kernel space.  This buffer must be at
 648  *         least @count bytes long.
 649  * @src:   Source address, in user space.
 650  * @count: Maximum number of bytes to copy, including the trailing NUL.
 651  *
 652  * Copies a NUL-terminated string from userspace to kernel space.
 653  * Caller must check the specified block with access_ok() before calling
 654  * this function.
 655  *
 656  * On success, returns the length of the string (not including the trailing
 657  * NUL).
 658  *
 659  * If access to userspace fails, returns -EFAULT (some data may have been
 660  * copied).
 661  *
 662  * If @count is smaller than the length of the string, copies @count bytes
 663  * and returns @count.
 664  */
 665 static inline long
 666 __strncpy_from_user(char *__to, const char *__from, long __len)
 667 {
 668         long res;
 669
 670         might_sleep();
 671         __asm__ __volatile__(
 672                 "move\t$4, %1\n\t"
 673                 "move\t$5, %2\n\t"
 674                 "move\t$6, %3\n\t"
 675                 __MODULE_JAL(__strncpy_from_user_nocheck_asm)
 676                 "move\t%0, $2"
 677                 : "=r" (res)
 678                 : "r" (__to), "r" (__from), "r" (__len)
 679                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 680
 681         return res;
 682 }
 683
 684 /*
 685  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 686  * @dst:   Destination address, in kernel space.  This buffer must be at
 687  *         least @count bytes long.
 688  * @src:   Source address, in user space.
 689  * @count: Maximum number of bytes to copy, including the trailing NUL.
 690  *
 691  * Copies a NUL-terminated string from userspace to kernel space.
 692  *
 693  * On success, returns the length of the string (not including the trailing
 694  * NUL).
 695  *
 696  * If access to userspace fails, returns -EFAULT (some data may have been
 697  * copied).
 698  *
 699  * If @count is smaller than the length of the string, copies @count bytes
 700  * and returns @count.
 701  */
 702 static inline long
 703 strncpy_from_user(char *__to, const char *__from, long __len)
 704 {
 705         long res;
 706
 707         might_sleep();
 708         __asm__ __volatile__(
 709                 "move\t$4, %1\n\t"
 710                 "move\t$5, %2\n\t"
 711                 "move\t$6, %3\n\t"
 712                 __MODULE_JAL(__strncpy_from_user_asm)
 713                 "move\t%0, $2"
 714                 : "=r" (res)
 715                 : "r" (__to), "r" (__from), "r" (__len)
 716                 : "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
 717
 718         return res;
 719 }
 720
 721 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 722 static inline long __strlen_user(const char *s)
 723 {
 724         long res;
 725
 726         might_sleep();
 727         __asm__ __volatile__(
 728                 "move\t$4, %1\n\t"
 729                 __MODULE_JAL(__strlen_user_nocheck_asm)
 730                 "move\t%0, $2"
 731                 : "=r" (res)
 732                 : "r" (s)
 733                 : "$2", "$4", __UA_t0, "$31");
 734
 735         return res;
 736 }
 737
 738 /*
 739  * strlen_user: - Get the size of a string in user space.
 740  * @str: The string to measure.
 741  *
 742  * Context: User context only.  This function may sleep.
 743  *
 744  * Get the size of a NUL-terminated string in user space.
 745  *
 746  * Returns the size of the string INCLUDING the terminating NUL.
 747  * On exception, returns 0.
 748  *
 749  * If there is a limit on the length of a valid string, you may wish to
 750  * consider using strnlen_user() instead.
 751  */
 752 static inline long strlen_user(const char *s)
 753 {
 754         long res;
 755
 756         might_sleep();
 757         __asm__ __volatile__(
 758                 "move\t$4, %1\n\t"
 759                 __MODULE_JAL(__strlen_user_asm)
 760                 "move\t%0, $2"
 761                 : "=r" (res)
 762                 : "r" (s)
 763                 : "$2", "$4", __UA_t0, "$31");
 764
 765         return res;
 766 }
 767
 768 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 769 static inline long __strnlen_user(const char *s, long n)
 770 {
 771         long res;
 772
 773         might_sleep();
 774         __asm__ __volatile__(
 775                 "move\t$4, %1\n\t"
 776                 "move\t$5, %2\n\t"
 777                 __MODULE_JAL(__strnlen_user_nocheck_asm)
 778                 "move\t%0, $2"
 779                 : "=r" (res)
 780                 : "r" (s), "r" (n)
 781                 : "$2", "$4", "$5", __UA_t0, "$31");
 782
 783         return res;
 784 }
 785
 786 /*
 787  * strlen_user: - Get the size of a string in user space.
 788  * @str: The string to measure.
 789  *
 790  * Context: User context only.  This function may sleep.
 791  *
 792  * Get the size of a NUL-terminated string in user space.
 793  *
 794  * Returns the size of the string INCLUDING the terminating NUL.
 795  * On exception, returns 0.
 796  *
 797  * If there is a limit on the length of a valid string, you may wish to
 798  * consider using strnlen_user() instead.
 799  */
 800 static inline long strnlen_user(const char *s, long n)
 801 {
 802         long res;
 803
 804         might_sleep();
 805         __asm__ __volatile__(
 806                 "move\t$4, %1\n\t"
 807                 "move\t$5, %2\n\t"
 808                 __MODULE_JAL(__strnlen_user_asm)
 809                 "move\t%0, $2"
 810                 : "=r" (res)
 811                 : "r" (s), "r" (n)
 812                 : "$2", "$4", "$5", __UA_t0, "$31");
 813
 814         return res;
 815 }
 816
 817 struct exception_table_entry
 818 {
 819         unsigned long insn;
 820         unsigned long nextinsn;
 821 };
 822
 823 extern int fixup_exception(struct pt_regs *regs);
 824
 825 #endif /* _ASM_UACCESS_H */