arch/mn10300/include/asm/uaccess.h

   1 /* MN10300 userspace access functions
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #ifndef _ASM_UACCESS_H
  12 #define _ASM_UACCESS_H
  13
  14 /*
  15  * User space memory access functions
  16  */
  17 #include <linux/thread_info.h>
  18 #include <asm/page.h>
  19 #include <asm/errno.h>
  20
  21 #define VERIFY_READ 0
  22 #define VERIFY_WRITE 1
  23
  24 /*
  25  * The fs value determines whether argument validity checking should be
  26  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  27  * get_fs() == KERNEL_DS, checking is bypassed.
  28  *
  29  * For historical reasons, these macros are grossly misnamed.
  30  */
  31 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  32
  33 #define KERNEL_XDS      MAKE_MM_SEG(0xBFFFFFFF)
  34 #define KERNEL_DS       MAKE_MM_SEG(0x9FFFFFFF)
  35 #define USER_DS         MAKE_MM_SEG(TASK_SIZE)
  36
  37 #define get_ds()        (KERNEL_DS)
  38 #define get_fs()        (current_thread_info()->addr_limit)
  39 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  40 #define __kernel_ds_p() (current_thread_info()->addr_limit.seg == 0x9FFFFFFF)
  41
  42 #define segment_eq(a, b) ((a).seg == (b).seg)
  43
  44 #define __addr_ok(addr) \
  45         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
  46
  47 /*
  48  * check that a range of addresses falls within the current address limit
  49  */
  50 static inline int ___range_ok(unsigned long addr, unsigned int size)
  51 {
  52         int flag = 1, tmp;
  53
  54         asm("   add     %3,%1   \n"     /* set C-flag if addr + size > 4Gb */
  55             "   bcs     0f      \n"
  56             "   cmp     %4,%1   \n"     /* jump if addr+size>limit (error) */
  57             "   bhi     0f      \n"
  58             "   clr     %0      \n"     /* mark okay */
  59             "0:                 \n"
  60             : "=r"(flag), "=&r"(tmp)
  61             : "1"(addr), "ir"(size),
  62               "r"(current_thread_info()->addr_limit.seg), "0"(flag)
  63             : "cc"
  64             );
  65
  66         return flag;
  67 }
  68
  69 #define __range_ok(addr, size) ___range_ok((unsigned long)(addr), (u32)(size))
  70
  71 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
  72 #define __access_ok(addr, size)     (__range_ok((addr), (size)) == 0)
  73
  74 static inline int verify_area(int type, const void *addr, unsigned long size)
  75 {
  76         return access_ok(type, addr, size) ? 0 : -EFAULT;
  77 }
  78
  79
  80 /*
  81  * The exception table consists of pairs of addresses: the first is the
  82  * address of an instruction that is allowed to fault, and the second is
  83  * the address at which the program should continue.  No registers are
  84  * modified, so it is entirely up to the continuation code to figure out
  85  * what to do.
  86  *
  87  * All the routines below use bits of fixup code that are out of line
  88  * with the main instruction path.  This means when everything is well,
  89  * we don't even have to jump over them.  Further, they do not intrude
  90  * on our cache or tlb entries.
  91  */
  92
  93 struct exception_table_entry
  94 {
  95         unsigned long insn, fixup;
  96 };
  97
  98 /* Returns 0 if exception not found and fixup otherwise.  */
  99 extern int fixup_exception(struct pt_regs *regs);
 100
 101 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
 102 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
 103
 104 /*
 105  * The "__xxx" versions do not do address space checking, useful when
 106  * doing multiple accesses to the same area (the user has to do the
 107  * checks by hand with "access_ok()")
 108  */
 109 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 110 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 111
 112 /*
 113  * The "xxx_ret" versions return constant specified in third argument, if
 114  * something bad happens. These macros can be optimized for the
 115  * case of just returning from the function xxx_ret is used.
 116  */
 117
 118 #define put_user_ret(x, ptr, ret) \
 119         ({ if (put_user((x), (ptr)))    return (ret); })
 120 #define get_user_ret(x, ptr, ret) \
 121         ({ if (get_user((x), (ptr)))    return (ret); })
 122 #define __put_user_ret(x, ptr, ret) \
 123         ({ if (__put_user((x), (ptr)))  return (ret); })
 124 #define __get_user_ret(x, ptr, ret) \
 125         ({ if (__get_user((x), (ptr)))  return (ret); })
 126
 127 struct __large_struct { unsigned long buf[100]; };
 128 #define __m(x) (*(struct __large_struct *)(x))
 129
 130 #define __get_user_nocheck(x, ptr, size)                                \
 131 ({                                                                      \
 132         unsigned long __gu_addr;                                        \
 133         int __gu_err;                                                   \
 134         __gu_addr = (unsigned long) (ptr);                              \
 135         switch (size) {                                                 \
 136         case 1: {                                                       \
 137                 unsigned char __gu_val;                                 \
 138                 __get_user_asm("bu");                                   \
 139                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 140                 break;                                                  \
 141         }                                                               \
 142         case 2: {                                                       \
 143                 unsigned short __gu_val;                                \
 144                 __get_user_asm("hu");                                   \
 145                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 146                 break;                                                  \
 147         }                                                               \
 148         case 4: {                                                       \
 149                 unsigned int __gu_val;                                  \
 150                 __get_user_asm("");                                     \
 151                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 152                 break;                                                  \
 153         }                                                               \
 154         default:                                                        \
 155                 __get_user_unknown();                                   \
 156                 break;                                                  \
 157         }                                                               \
 158         __gu_err;                                                       \
 159 })
 160
 161 #define __get_user_check(x, ptr, size)                                  \
 162 ({                                                                      \
 163         int _e;                                                         \
 164         if (likely(__access_ok((unsigned long) (ptr), (size))))         \
 165                 _e = __get_user_nocheck((x), (ptr), (size));            \
 166         else {                                                          \
 167                 _e = -EFAULT;                                           \
 168                 (x) = (__typeof__(x))0;                                 \
 169         }                                                               \
 170         _e;                                                             \
 171 })
 172
 173 #define __get_user_asm(INSN)                                    \
 174 ({                                                              \
 175         asm volatile(                                   \
 176                 "1:\n"                                          \
 177                 "       mov"INSN"       %2,%1\n"                \
 178                 "       mov             0,%0\n"                 \
 179                 "2:\n"                                          \
 180                 "       .section        .fixup,\"ax\"\n"        \
 181                 "3:\n\t"                                        \
 182                 "       mov             %3,%0\n"                \
 183                 "       jmp             2b\n"                   \
 184                 "       .previous\n"                            \
 185                 "       .section        __ex_table,\"a\"\n"     \
 186                 "       .balign         4\n"                    \
 187                 "       .long           1b, 3b\n"               \
 188                 "       .previous"                              \
 189                 : "=&r" (__gu_err), "=&r" (__gu_val)            \
 190                 : "m" (__m(__gu_addr)), "i" (-EFAULT));         \
 191 })
 192
 193 extern int __get_user_unknown(void);
 194
 195 #define __put_user_nocheck(x, ptr, size)                        \
 196 ({                                                              \
 197         union {                                                 \
 198                 __typeof__(*(ptr)) val;                         \
 199                 u32 bits[2];                                    \
 200         } __pu_val;                                             \
 201         unsigned long __pu_addr;                                \
 202         int __pu_err;                                           \
 203         __pu_val.val = (x);                                     \
 204         __pu_addr = (unsigned long) (ptr);                      \
 205         switch (size) {                                         \
 206         case 1:  __put_user_asm("bu"); break;                   \
 207         case 2:  __put_user_asm("hu"); break;                   \
 208         case 4:  __put_user_asm(""  ); break;                   \
 209         case 8:  __put_user_asm8();    break;                   \
 210         default: __pu_err = __put_user_unknown(); break;        \
 211         }                                                       \
 212         __pu_err;                                               \
 213 })
 214
 215 #define __put_user_check(x, ptr, size)                                  \
 216 ({                                                                      \
 217         union {                                                         \
 218                 __typeof__(*(ptr)) val;                                 \
 219                 u32 bits[2];                                            \
 220         } __pu_val;                                                     \
 221         unsigned long __pu_addr;                                        \
 222         int __pu_err;                                                   \
 223         __pu_val.val = (x);                                             \
 224         __pu_addr = (unsigned long) (ptr);                              \
 225         if (likely(__access_ok(__pu_addr, size))) {                     \
 226                 switch (size) {                                         \
 227                 case 1:  __put_user_asm("bu"); break;                   \
 228                 case 2:  __put_user_asm("hu"); break;                   \
 229                 case 4:  __put_user_asm(""  ); break;                   \
 230                 case 8:  __put_user_asm8();    break;                   \
 231                 default: __pu_err = __put_user_unknown(); break;        \
 232                 }                                                       \
 233         }                                                               \
 234         else {                                                          \
 235                 __pu_err = -EFAULT;                                     \
 236         }                                                               \
 237         __pu_err;                                                       \
 238 })
 239
 240 #define __put_user_asm(INSN)                                    \
 241 ({                                                              \
 242         asm volatile(                                           \
 243                 "1:\n"                                          \
 244                 "       mov"INSN"       %1,%2\n"                \
 245                 "       mov             0,%0\n"                 \
 246                 "2:\n"                                          \
 247                 "       .section        .fixup,\"ax\"\n"        \
 248                 "3:\n"                                          \
 249                 "       mov             %3,%0\n"                \
 250                 "       jmp             2b\n"                   \
 251                 "       .previous\n"                            \
 252                 "       .section        __ex_table,\"a\"\n"     \
 253                 "       .balign         4\n"                    \
 254                 "       .long           1b, 3b\n"               \
 255                 "       .previous"                              \
 256                 : "=&r" (__pu_err)                              \
 257                 : "r" (__pu_val.val), "m" (__m(__pu_addr)),     \
 258                   "i" (-EFAULT)                                 \
 259                 );                                              \
 260 })
 261
 262 #define __put_user_asm8()                                               \
 263 ({                                                                      \
 264         asm volatile(                                                   \
 265                 "1:     mov             %1,%3           \n"             \
 266                 "2:     mov             %2,%4           \n"             \
 267                 "       mov             0,%0            \n"             \
 268                 "3:                                     \n"             \
 269                 "       .section        .fixup,\"ax\"   \n"             \
 270                 "4:                                     \n"             \
 271                 "       mov             %5,%0           \n"             \
 272                 "       jmp             3b              \n"             \
 273                 "       .previous                       \n"             \
 274                 "       .section        __ex_table,\"a\"\n"             \
 275                 "       .balign         4               \n"             \
 276                 "       .long           1b, 4b          \n"             \
 277                 "       .long           2b, 4b          \n"             \
 278                 "       .previous                       \n"             \
 279                 : "=&r" (__pu_err)                                      \
 280                 : "r" (__pu_val.bits[0]), "r" (__pu_val.bits[1]),       \
 281                   "m" (__m(__pu_addr)), "m" (__m(__pu_addr+4)),         \
 282                   "i" (-EFAULT)                                         \
 283                 );                                                      \
 284 })
 285
 286 extern int __put_user_unknown(void);
 287
 288
 289 /*
 290  * Copy To/From Userspace
 291  */
 292 /* Generic arbitrary sized copy.  */
 293 #define __copy_user(to, from, size)                                     \
 294 do {                                                                    \
 295         if (size) {                                                     \
 296                 void *__to = to;                                        \
 297                 const void *__from = from;                              \
 298                 int w;                                                  \
 299                 asm volatile(                                           \
 300                         "0:     movbu   (%0),%3;\n"                     \
 301                         "1:     movbu   %3,(%1);\n"                     \
 302                         "       inc     %0;\n"                          \
 303                         "       inc     %1;\n"                          \
 304                         "       add     -1,%2;\n"                       \
 305                         "       bne     0b;\n"                          \
 306                         "2:\n"                                          \
 307                         "       .section .fixup,\"ax\"\n"               \
 308                         "3:     jmp     2b\n"                           \
 309                         "       .previous\n"                            \
 310                         "       .section __ex_table,\"a\"\n"            \
 311                         "       .balign 4\n"                            \
 312                         "       .long   0b,3b\n"                        \
 313                         "       .long   1b,3b\n"                        \
 314                         "       .previous\n"                            \
 315                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 316                         : "0"(__from), "1"(__to), "2"(size)             \
 317                         : "cc", "memory");                              \
 318         }                                                               \
 319 } while (0)
 320
 321 #define __copy_user_zeroing(to, from, size)                             \
 322 do {                                                                    \
 323         if (size) {                                                     \
 324                 void *__to = to;                                        \
 325                 const void *__from = from;                              \
 326                 int w;                                                  \
 327                 asm volatile(                                           \
 328                         "0:     movbu   (%0),%3;\n"                     \
 329                         "1:     movbu   %3,(%1);\n"                     \
 330                         "       inc     %0;\n"                          \
 331                         "       inc     %1;\n"                          \
 332                         "       add     -1,%2;\n"                       \
 333                         "       bne     0b;\n"                          \
 334                         "2:\n"                                          \
 335                         "       .section .fixup,\"ax\"\n"               \
 336                         "3:\n"                                          \
 337                         "       mov     %2,%0\n"                        \
 338                         "       clr     %3\n"                           \
 339                         "4:     movbu   %3,(%1);\n"                     \
 340                         "       inc     %1;\n"                          \
 341                         "       add     -1,%2;\n"                       \
 342                         "       bne     4b;\n"                          \
 343                         "       mov     %0,%2\n"                        \
 344                         "       jmp     2b\n"                           \
 345                         "       .previous\n"                            \
 346                         "       .section __ex_table,\"a\"\n"            \
 347                         "       .balign 4\n"                            \
 348                         "       .long   0b,3b\n"                        \
 349                         "       .long   1b,3b\n"                        \
 350                         "       .previous\n"                            \
 351                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 352                         : "0"(__from), "1"(__to), "2"(size)             \
 353                         : "cc", "memory");                              \
 354         }                                                               \
 355 } while (0)
 356
 357 /* We let the __ versions of copy_from/to_user inline, because they're often
 358  * used in fast paths and have only a small space overhead.
 359  */
 360 static inline
 361 unsigned long __generic_copy_from_user_nocheck(void *to, const void *from,
 362                                                unsigned long n)
 363 {
 364         __copy_user_zeroing(to, from, n);
 365         return n;
 366 }
 367
 368 static inline
 369 unsigned long __generic_copy_to_user_nocheck(void *to, const void *from,
 370                                              unsigned long n)
 371 {
 372         __copy_user(to, from, n);
 373         return n;
 374 }
 375
 376
 377 #if 0
 378 #error "don't use - these macros don't increment to & from pointers"
 379 /* Optimize just a little bit when we know the size of the move. */
 380 #define __constant_copy_user(to, from, size)    \
 381 do {                                            \
 382         asm volatile(                           \
 383                 "       mov %0,a0;\n"           \
 384                 "0:     movbu (%1),d3;\n"       \
 385                 "1:     movbu d3,(%2);\n"       \
 386                 "       add -1,a0;\n"           \
 387                 "       bne 0b;\n"              \
 388                 "2:;"                           \
 389                 ".section .fixup,\"ax\"\n"      \
 390                 "3:     jmp 2b\n"               \
 391                 ".previous\n"                   \
 392                 ".section __ex_table,\"a\"\n"   \
 393                 "       .balign 4\n"            \
 394                 "       .long 0b,3b\n"          \
 395                 "       .long 1b,3b\n"          \
 396                 ".previous"                     \
 397                 :                               \
 398                 : "d"(size), "d"(to), "d"(from) \
 399                 : "d3", "a0");                  \
 400 } while (0)
 401
 402 /* Optimize just a little bit when we know the size of the move. */
 403 #define __constant_copy_user_zeroing(to, from, size)    \
 404 do {                                                    \
 405         asm volatile(                                   \
 406                 "       mov %0,a0;\n"                   \
 407                 "0:     movbu (%1),d3;\n"               \
 408                 "1:     movbu d3,(%2);\n"               \
 409                 "       add -1,a0;\n"                   \
 410                 "       bne 0b;\n"                      \
 411                 "2:;"                                   \
 412                 ".section .fixup,\"ax\"\n"              \
 413                 "3:     jmp 2b\n"                       \
 414                 ".previous\n"                           \
 415                 ".section __ex_table,\"a\"\n"           \
 416                 "       .balign 4\n"                    \
 417                 "       .long 0b,3b\n"                  \
 418                 "       .long 1b,3b\n"                  \
 419                 ".previous"                             \
 420                 :                                       \
 421                 : "d"(size), "d"(to), "d"(from)         \
 422                 : "d3", "a0");                          \
 423 } while (0)
 424
 425 static inline
 426 unsigned long __constant_copy_to_user(void *to, const void *from,
 427                                       unsigned long n)
 428 {
 429         if (access_ok(VERIFY_WRITE, to, n))
 430                 __constant_copy_user(to, from, n);
 431         return n;
 432 }
 433
 434 static inline
 435 unsigned long __constant_copy_from_user(void *to, const void *from,
 436                                         unsigned long n)
 437 {
 438         if (access_ok(VERIFY_READ, from, n))
 439                 __constant_copy_user_zeroing(to, from, n);
 440         return n;
 441 }
 442
 443 static inline
 444 unsigned long __constant_copy_to_user_nocheck(void *to, const void *from,
 445                                               unsigned long n)
 446 {
 447         __constant_copy_user(to, from, n);
 448         return n;
 449 }
 450
 451 static inline
 452 unsigned long __constant_copy_from_user_nocheck(void *to, const void *from,
 453                                                 unsigned long n)
 454 {
 455         __constant_copy_user_zeroing(to, from, n);
 456         return n;
 457 }
 458 #endif
 459
 460 extern unsigned long __generic_copy_to_user(void __user *, const void *,
 461                                             unsigned long);
 462 extern unsigned long __generic_copy_from_user(void *, const void __user *,
 463                                               unsigned long);
 464
 465 #define __copy_to_user_inatomic(to, from, n) \
 466         __generic_copy_to_user_nocheck((to), (from), (n))
 467 #define __copy_from_user_inatomic(to, from, n) \
 468         __generic_copy_from_user_nocheck((to), (from), (n))
 469
 470 #define __copy_to_user(to, from, n)                     \
 471 ({                                                      \
 472         might_sleep();                                  \
 473         __copy_to_user_inatomic((to), (from), (n));     \
 474 })
 475
 476 #define __copy_from_user(to, from, n)                   \
 477 ({                                                      \
 478         might_sleep();                                  \
 479         __copy_from_user_inatomic((to), (from), (n));   \
 480 })
 481
 482
 483 #define copy_to_user(to, from, n)   __generic_copy_to_user((to), (from), (n))
 484 #define copy_from_user(to, from, n) __generic_copy_from_user((to), (from), (n))
 485
 486 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 487 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 488 extern long strnlen_user(const char __user *str, long n);
 489 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
 490 extern unsigned long clear_user(void __user *mem, unsigned long len);
 491 extern unsigned long __clear_user(void __user *mem, unsigned long len);
 492
 493 #endif /* _ASM_UACCESS_H */