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 <linux/kernel.h>
  19 #include <asm/page.h>
  20 #include <asm/errno.h>
  21
  22 #define VERIFY_READ 0
  23 #define VERIFY_WRITE 1
  24
  25 /*
  26  * The fs value determines whether argument validity checking should be
  27  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  28  * get_fs() == KERNEL_DS, checking is bypassed.
  29  *
  30  * For historical reasons, these macros are grossly misnamed.
  31  */
  32 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  33
  34 #define KERNEL_XDS      MAKE_MM_SEG(0xBFFFFFFF)
  35 #define KERNEL_DS       MAKE_MM_SEG(0x9FFFFFFF)
  36 #define USER_DS         MAKE_MM_SEG(TASK_SIZE)
  37
  38 #define get_ds()        (KERNEL_DS)
  39 #define get_fs()        (current_thread_info()->addr_limit)
  40 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  41 #define __kernel_ds_p() (current_thread_info()->addr_limit.seg == 0x9FFFFFFF)
  42
  43 #define segment_eq(a, b) ((a).seg == (b).seg)
  44
  45 #define __addr_ok(addr) \
  46         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
  47
  48 /*
  49  * check that a range of addresses falls within the current address limit
  50  */
  51 static inline int ___range_ok(unsigned long addr, unsigned int size)
  52 {
  53         int flag = 1, tmp;
  54
  55         asm("   add     %3,%1   \n"     /* set C-flag if addr + size > 4Gb */
  56             "   bcs     0f      \n"
  57             "   cmp     %4,%1   \n"     /* jump if addr+size>limit (error) */
  58             "   bhi     0f      \n"
  59             "   clr     %0      \n"     /* mark okay */
  60             "0:                 \n"
  61             : "=r"(flag), "=&r"(tmp)
  62             : "1"(addr), "ir"(size),
  63               "r"(current_thread_info()->addr_limit.seg), "0"(flag)
  64             : "cc"
  65             );
  66
  67         return flag;
  68 }
  69
  70 #define __range_ok(addr, size) ___range_ok((unsigned long)(addr), (u32)(size))
  71
  72 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
  73 #define __access_ok(addr, size)     (__range_ok((addr), (size)) == 0)
  74
  75 static inline int verify_area(int type, const void *addr, unsigned long size)
  76 {
  77         return access_ok(type, addr, size) ? 0 : -EFAULT;
  78 }
  79
  80
  81 /*
  82  * The exception table consists of pairs of addresses: the first is the
  83  * address of an instruction that is allowed to fault, and the second is
  84  * the address at which the program should continue.  No registers are
  85  * modified, so it is entirely up to the continuation code to figure out
  86  * what to do.
  87  *
  88  * All the routines below use bits of fixup code that are out of line
  89  * with the main instruction path.  This means when everything is well,
  90  * we don't even have to jump over them.  Further, they do not intrude
  91  * on our cache or tlb entries.
  92  */
  93
  94 struct exception_table_entry
  95 {
  96         unsigned long insn, fixup;
  97 };
  98
  99 /* Returns 0 if exception not found and fixup otherwise.  */
 100 extern int fixup_exception(struct pt_regs *regs);
 101
 102 #define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
 103 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
 104
 105 /*
 106  * The "__xxx" versions do not do address space checking, useful when
 107  * doing multiple accesses to the same area (the user has to do the
 108  * checks by hand with "access_ok()")
 109  */
 110 #define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 111 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 112
 113 /*
 114  * The "xxx_ret" versions return constant specified in third argument, if
 115  * something bad happens. These macros can be optimized for the
 116  * case of just returning from the function xxx_ret is used.
 117  */
 118
 119 #define put_user_ret(x, ptr, ret) \
 120         ({ if (put_user((x), (ptr)))    return (ret); })
 121 #define get_user_ret(x, ptr, ret) \
 122         ({ if (get_user((x), (ptr)))    return (ret); })
 123 #define __put_user_ret(x, ptr, ret) \
 124         ({ if (__put_user((x), (ptr)))  return (ret); })
 125 #define __get_user_ret(x, ptr, ret) \
 126         ({ if (__get_user((x), (ptr)))  return (ret); })
 127
 128 struct __large_struct { unsigned long buf[100]; };
 129 #define __m(x) (*(struct __large_struct *)(x))
 130
 131 #define __get_user_nocheck(x, ptr, size)                                \
 132 ({                                                                      \
 133         unsigned long __gu_addr;                                        \
 134         int __gu_err;                                                   \
 135         __gu_addr = (unsigned long) (ptr);                              \
 136         switch (size) {                                                 \
 137         case 1: {                                                       \
 138                 unsigned char __gu_val;                                 \
 139                 __get_user_asm("bu");                                   \
 140                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 141                 break;                                                  \
 142         }                                                               \
 143         case 2: {                                                       \
 144                 unsigned short __gu_val;                                \
 145                 __get_user_asm("hu");                                   \
 146                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 147                 break;                                                  \
 148         }                                                               \
 149         case 4: {                                                       \
 150                 unsigned int __gu_val;                                  \
 151                 __get_user_asm("");                                     \
 152                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 153                 break;                                                  \
 154         }                                                               \
 155         default:                                                        \
 156                 __get_user_unknown();                                   \
 157                 break;                                                  \
 158         }                                                               \
 159         __gu_err;                                                       \
 160 })
 161
 162 #define __get_user_check(x, ptr, size)                                  \
 163 ({                                                                      \
 164         const __typeof__(ptr) __guc_ptr = (ptr);                        \
 165         int _e;                                                         \
 166         if (likely(__access_ok((unsigned long) __guc_ptr, (size))))     \
 167                 _e = __get_user_nocheck((x), __guc_ptr, (size));        \
 168         else {                                                          \
 169                 _e = -EFAULT;                                           \
 170                 (x) = (__typeof__(x))0;                                 \
 171         }                                                               \
 172         _e;                                                             \
 173 })
 174
 175 #define __get_user_asm(INSN)                                    \
 176 ({                                                              \
 177         asm volatile(                                   \
 178                 "1:\n"                                          \
 179                 "       mov"INSN"       %2,%1\n"                \
 180                 "       mov             0,%0\n"                 \
 181                 "2:\n"                                          \
 182                 "       .section        .fixup,\"ax\"\n"        \
 183                 "3:\n\t"                                        \
 184                 "       mov             0,%1\n"                 \
 185                 "       mov             %3,%0\n"                \
 186                 "       jmp             2b\n"                   \
 187                 "       .previous\n"                            \
 188                 "       .section        __ex_table,\"a\"\n"     \
 189                 "       .balign         4\n"                    \
 190                 "       .long           1b, 3b\n"               \
 191                 "       .previous"                              \
 192                 : "=&r" (__gu_err), "=&r" (__gu_val)            \
 193                 : "m" (__m(__gu_addr)), "i" (-EFAULT));         \
 194 })
 195
 196 extern int __get_user_unknown(void);
 197
 198 #define __put_user_nocheck(x, ptr, size)                        \
 199 ({                                                              \
 200         union {                                                 \
 201                 __typeof__(*(ptr)) val;                         \
 202                 u32 bits[2];                                    \
 203         } __pu_val;                                             \
 204         unsigned long __pu_addr;                                \
 205         int __pu_err;                                           \
 206         __pu_val.val = (x);                                     \
 207         __pu_addr = (unsigned long) (ptr);                      \
 208         switch (size) {                                         \
 209         case 1:  __put_user_asm("bu"); break;                   \
 210         case 2:  __put_user_asm("hu"); break;                   \
 211         case 4:  __put_user_asm(""  ); break;                   \
 212         case 8:  __put_user_asm8();    break;                   \
 213         default: __pu_err = __put_user_unknown(); break;        \
 214         }                                                       \
 215         __pu_err;                                               \
 216 })
 217
 218 #define __put_user_check(x, ptr, size)                                  \
 219 ({                                                                      \
 220         union {                                                         \
 221                 __typeof__(*(ptr)) val;                                 \
 222                 u32 bits[2];                                            \
 223         } __pu_val;                                                     \
 224         unsigned long __pu_addr;                                        \
 225         int __pu_err;                                                   \
 226         __pu_val.val = (x);                                             \
 227         __pu_addr = (unsigned long) (ptr);                              \
 228         if (likely(__access_ok(__pu_addr, size))) {                     \
 229                 switch (size) {                                         \
 230                 case 1:  __put_user_asm("bu"); break;                   \
 231                 case 2:  __put_user_asm("hu"); break;                   \
 232                 case 4:  __put_user_asm(""  ); break;                   \
 233                 case 8:  __put_user_asm8();    break;                   \
 234                 default: __pu_err = __put_user_unknown(); break;        \
 235                 }                                                       \
 236         }                                                               \
 237         else {                                                          \
 238                 __pu_err = -EFAULT;                                     \
 239         }                                                               \
 240         __pu_err;                                                       \
 241 })
 242
 243 #define __put_user_asm(INSN)                                    \
 244 ({                                                              \
 245         asm volatile(                                           \
 246                 "1:\n"                                          \
 247                 "       mov"INSN"       %1,%2\n"                \
 248                 "       mov             0,%0\n"                 \
 249                 "2:\n"                                          \
 250                 "       .section        .fixup,\"ax\"\n"        \
 251                 "3:\n"                                          \
 252                 "       mov             %3,%0\n"                \
 253                 "       jmp             2b\n"                   \
 254                 "       .previous\n"                            \
 255                 "       .section        __ex_table,\"a\"\n"     \
 256                 "       .balign         4\n"                    \
 257                 "       .long           1b, 3b\n"               \
 258                 "       .previous"                              \
 259                 : "=&r" (__pu_err)                              \
 260                 : "r" (__pu_val.val), "m" (__m(__pu_addr)),     \
 261                   "i" (-EFAULT)                                 \
 262                 );                                              \
 263 })
 264
 265 #define __put_user_asm8()                                               \
 266 ({                                                                      \
 267         asm volatile(                                                   \
 268                 "1:     mov             %1,%3           \n"             \
 269                 "2:     mov             %2,%4           \n"             \
 270                 "       mov             0,%0            \n"             \
 271                 "3:                                     \n"             \
 272                 "       .section        .fixup,\"ax\"   \n"             \
 273                 "4:                                     \n"             \
 274                 "       mov             %5,%0           \n"             \
 275                 "       jmp             3b              \n"             \
 276                 "       .previous                       \n"             \
 277                 "       .section        __ex_table,\"a\"\n"             \
 278                 "       .balign         4               \n"             \
 279                 "       .long           1b, 4b          \n"             \
 280                 "       .long           2b, 4b          \n"             \
 281                 "       .previous                       \n"             \
 282                 : "=&r" (__pu_err)                                      \
 283                 : "r" (__pu_val.bits[0]), "r" (__pu_val.bits[1]),       \
 284                   "m" (__m(__pu_addr)), "m" (__m(__pu_addr+4)),         \
 285                   "i" (-EFAULT)                                         \
 286                 );                                                      \
 287 })
 288
 289 extern int __put_user_unknown(void);
 290
 291
 292 /*
 293  * Copy To/From Userspace
 294  */
 295 /* Generic arbitrary sized copy.  */
 296 #define __copy_user(to, from, size)                                     \
 297 do {                                                                    \
 298         if (size) {                                                     \
 299                 void *__to = to;                                        \
 300                 const void *__from = from;                              \
 301                 int w;                                                  \
 302                 asm volatile(                                           \
 303                         "0:     movbu   (%0),%3;\n"                     \
 304                         "1:     movbu   %3,(%1);\n"                     \
 305                         "       inc     %0;\n"                          \
 306                         "       inc     %1;\n"                          \
 307                         "       add     -1,%2;\n"                       \
 308                         "       bne     0b;\n"                          \
 309                         "2:\n"                                          \
 310                         "       .section .fixup,\"ax\"\n"               \
 311                         "3:     jmp     2b\n"                           \
 312                         "       .previous\n"                            \
 313                         "       .section __ex_table,\"a\"\n"            \
 314                         "       .balign 4\n"                            \
 315                         "       .long   0b,3b\n"                        \
 316                         "       .long   1b,3b\n"                        \
 317                         "       .previous\n"                            \
 318                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 319                         : "0"(__from), "1"(__to), "2"(size)             \
 320                         : "cc", "memory");                              \
 321         }                                                               \
 322 } while (0)
 323
 324 #define __copy_user_zeroing(to, from, size)                             \
 325 do {                                                                    \
 326         if (size) {                                                     \
 327                 void *__to = to;                                        \
 328                 const void *__from = from;                              \
 329                 int w;                                                  \
 330                 asm volatile(                                           \
 331                         "0:     movbu   (%0),%3;\n"                     \
 332                         "1:     movbu   %3,(%1);\n"                     \
 333                         "       inc     %0;\n"                          \
 334                         "       inc     %1;\n"                          \
 335                         "       add     -1,%2;\n"                       \
 336                         "       bne     0b;\n"                          \
 337                         "2:\n"                                          \
 338                         "       .section .fixup,\"ax\"\n"               \
 339                         "3:\n"                                          \
 340                         "       mov     %2,%0\n"                        \
 341                         "       clr     %3\n"                           \
 342                         "4:     movbu   %3,(%1);\n"                     \
 343                         "       inc     %1;\n"                          \
 344                         "       add     -1,%2;\n"                       \
 345                         "       bne     4b;\n"                          \
 346                         "       mov     %0,%2\n"                        \
 347                         "       jmp     2b\n"                           \
 348                         "       .previous\n"                            \
 349                         "       .section __ex_table,\"a\"\n"            \
 350                         "       .balign 4\n"                            \
 351                         "       .long   0b,3b\n"                        \
 352                         "       .long   1b,3b\n"                        \
 353                         "       .previous\n"                            \
 354                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 355                         : "0"(__from), "1"(__to), "2"(size)             \
 356                         : "cc", "memory");                              \
 357         }                                                               \
 358 } while (0)
 359
 360 /* We let the __ versions of copy_from/to_user inline, because they're often
 361  * used in fast paths and have only a small space overhead.
 362  */
 363 static inline
 364 unsigned long __generic_copy_from_user_nocheck(void *to, const void *from,
 365                                                unsigned long n)
 366 {
 367         __copy_user_zeroing(to, from, n);
 368         return n;
 369 }
 370
 371 static inline
 372 unsigned long __generic_copy_to_user_nocheck(void *to, const void *from,
 373                                              unsigned long n)
 374 {
 375         __copy_user(to, from, n);
 376         return n;
 377 }
 378
 379
 380 #if 0
 381 #error "don't use - these macros don't increment to & from pointers"
 382 /* Optimize just a little bit when we know the size of the move. */
 383 #define __constant_copy_user(to, from, size)    \
 384 do {                                            \
 385         asm volatile(                           \
 386                 "       mov %0,a0;\n"           \
 387                 "0:     movbu (%1),d3;\n"       \
 388                 "1:     movbu d3,(%2);\n"       \
 389                 "       add -1,a0;\n"           \
 390                 "       bne 0b;\n"              \
 391                 "2:;"                           \
 392                 ".section .fixup,\"ax\"\n"      \
 393                 "3:     jmp 2b\n"               \
 394                 ".previous\n"                   \
 395                 ".section __ex_table,\"a\"\n"   \
 396                 "       .balign 4\n"            \
 397                 "       .long 0b,3b\n"          \
 398                 "       .long 1b,3b\n"          \
 399                 ".previous"                     \
 400                 :                               \
 401                 : "d"(size), "d"(to), "d"(from) \
 402                 : "d3", "a0");                  \
 403 } while (0)
 404
 405 /* Optimize just a little bit when we know the size of the move. */
 406 #define __constant_copy_user_zeroing(to, from, size)    \
 407 do {                                                    \
 408         asm volatile(                                   \
 409                 "       mov %0,a0;\n"                   \
 410                 "0:     movbu (%1),d3;\n"               \
 411                 "1:     movbu d3,(%2);\n"               \
 412                 "       add -1,a0;\n"                   \
 413                 "       bne 0b;\n"                      \
 414                 "2:;"                                   \
 415                 ".section .fixup,\"ax\"\n"              \
 416                 "3:     jmp 2b\n"                       \
 417                 ".previous\n"                           \
 418                 ".section __ex_table,\"a\"\n"           \
 419                 "       .balign 4\n"                    \
 420                 "       .long 0b,3b\n"                  \
 421                 "       .long 1b,3b\n"                  \
 422                 ".previous"                             \
 423                 :                                       \
 424                 : "d"(size), "d"(to), "d"(from)         \
 425                 : "d3", "a0");                          \
 426 } while (0)
 427
 428 static inline
 429 unsigned long __constant_copy_to_user(void *to, const void *from,
 430                                       unsigned long n)
 431 {
 432         if (access_ok(VERIFY_WRITE, to, n))
 433                 __constant_copy_user(to, from, n);
 434         return n;
 435 }
 436
 437 static inline
 438 unsigned long __constant_copy_from_user(void *to, const void *from,
 439                                         unsigned long n)
 440 {
 441         if (access_ok(VERIFY_READ, from, n))
 442                 __constant_copy_user_zeroing(to, from, n);
 443         return n;
 444 }
 445
 446 static inline
 447 unsigned long __constant_copy_to_user_nocheck(void *to, const void *from,
 448                                               unsigned long n)
 449 {
 450         __constant_copy_user(to, from, n);
 451         return n;
 452 }
 453
 454 static inline
 455 unsigned long __constant_copy_from_user_nocheck(void *to, const void *from,
 456                                                 unsigned long n)
 457 {
 458         __constant_copy_user_zeroing(to, from, n);
 459         return n;
 460 }
 461 #endif
 462
 463 extern unsigned long __generic_copy_to_user(void __user *, const void *,
 464                                             unsigned long);
 465 extern unsigned long __generic_copy_from_user(void *, const void __user *,
 466                                               unsigned long);
 467
 468 #define __copy_to_user_inatomic(to, from, n) \
 469         __generic_copy_to_user_nocheck((to), (from), (n))
 470 #define __copy_from_user_inatomic(to, from, n) \
 471         __generic_copy_from_user_nocheck((to), (from), (n))
 472
 473 #define __copy_to_user(to, from, n)                     \
 474 ({                                                      \
 475         might_sleep();                                  \
 476         __copy_to_user_inatomic((to), (from), (n));     \
 477 })
 478
 479 #define __copy_from_user(to, from, n)                   \
 480 ({                                                      \
 481         might_sleep();                                  \
 482         __copy_from_user_inatomic((to), (from), (n));   \
 483 })
 484
 485
 486 #define copy_to_user(to, from, n)   __generic_copy_to_user((to), (from), (n))
 487 #define copy_from_user(to, from, n) __generic_copy_from_user((to), (from), (n))
 488
 489 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 490 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 491 extern long strnlen_user(const char __user *str, long n);
 492 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
 493 extern unsigned long clear_user(void __user *mem, unsigned long len);
 494 extern unsigned long __clear_user(void __user *mem, unsigned long len);
 495
 496 #endif /* _ASM_UACCESS_H */