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 struct __large_struct { unsigned long buf[100]; };
 114 #define __m(x) (*(struct __large_struct *)(x))
 115
 116 #define __get_user_nocheck(x, ptr, size)                                \
 117 ({                                                                      \
 118         unsigned long __gu_addr;                                        \
 119         int __gu_err;                                                   \
 120         __gu_addr = (unsigned long) (ptr);                              \
 121         switch (size) {                                                 \
 122         case 1: {                                                       \
 123                 unsigned char __gu_val;                                 \
 124                 __get_user_asm("bu");                                   \
 125                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 126                 break;                                                  \
 127         }                                                               \
 128         case 2: {                                                       \
 129                 unsigned short __gu_val;                                \
 130                 __get_user_asm("hu");                                   \
 131                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 132                 break;                                                  \
 133         }                                                               \
 134         case 4: {                                                       \
 135                 unsigned int __gu_val;                                  \
 136                 __get_user_asm("");                                     \
 137                 (x) = *(__force __typeof__(*(ptr))*) &__gu_val;         \
 138                 break;                                                  \
 139         }                                                               \
 140         default:                                                        \
 141                 __get_user_unknown();                                   \
 142                 break;                                                  \
 143         }                                                               \
 144         __gu_err;                                                       \
 145 })
 146
 147 #define __get_user_check(x, ptr, size)                                  \
 148 ({                                                                      \
 149         const __typeof__(*(ptr))* __guc_ptr = (ptr);                    \
 150         int _e;                                                         \
 151         if (likely(__access_ok((unsigned long) __guc_ptr, (size))))     \
 152                 _e = __get_user_nocheck((x), __guc_ptr, (size));        \
 153         else {                                                          \
 154                 _e = -EFAULT;                                           \
 155                 (x) = (__typeof__(x))0;                                 \
 156         }                                                               \
 157         _e;                                                             \
 158 })
 159
 160 #define __get_user_asm(INSN)                                    \
 161 ({                                                              \
 162         asm volatile(                                   \
 163                 "1:\n"                                          \
 164                 "       mov"INSN"       %2,%1\n"                \
 165                 "       mov             0,%0\n"                 \
 166                 "2:\n"                                          \
 167                 "       .section        .fixup,\"ax\"\n"        \
 168                 "3:\n\t"                                        \
 169                 "       mov             0,%1\n"                 \
 170                 "       mov             %3,%0\n"                \
 171                 "       jmp             2b\n"                   \
 172                 "       .previous\n"                            \
 173                 "       .section        __ex_table,\"a\"\n"     \
 174                 "       .balign         4\n"                    \
 175                 "       .long           1b, 3b\n"               \
 176                 "       .previous"                              \
 177                 : "=&r" (__gu_err), "=&r" (__gu_val)            \
 178                 : "m" (__m(__gu_addr)), "i" (-EFAULT));         \
 179 })
 180
 181 extern int __get_user_unknown(void);
 182
 183 #define __put_user_nocheck(x, ptr, size)                        \
 184 ({                                                              \
 185         union {                                                 \
 186                 __typeof__(*(ptr)) val;                         \
 187                 u32 bits[2];                                    \
 188         } __pu_val;                                             \
 189         unsigned long __pu_addr;                                \
 190         int __pu_err;                                           \
 191         __pu_val.val = (x);                                     \
 192         __pu_addr = (unsigned long) (ptr);                      \
 193         switch (size) {                                         \
 194         case 1:  __put_user_asm("bu"); break;                   \
 195         case 2:  __put_user_asm("hu"); break;                   \
 196         case 4:  __put_user_asm(""  ); break;                   \
 197         case 8:  __put_user_asm8();    break;                   \
 198         default: __pu_err = __put_user_unknown(); break;        \
 199         }                                                       \
 200         __pu_err;                                               \
 201 })
 202
 203 #define __put_user_check(x, ptr, size)                                  \
 204 ({                                                                      \
 205         union {                                                         \
 206                 __typeof__(*(ptr)) val;                                 \
 207                 u32 bits[2];                                            \
 208         } __pu_val;                                                     \
 209         unsigned long __pu_addr;                                        \
 210         int __pu_err;                                                   \
 211         __pu_val.val = (x);                                             \
 212         __pu_addr = (unsigned long) (ptr);                              \
 213         if (likely(__access_ok(__pu_addr, size))) {                     \
 214                 switch (size) {                                         \
 215                 case 1:  __put_user_asm("bu"); break;                   \
 216                 case 2:  __put_user_asm("hu"); break;                   \
 217                 case 4:  __put_user_asm(""  ); break;                   \
 218                 case 8:  __put_user_asm8();    break;                   \
 219                 default: __pu_err = __put_user_unknown(); break;        \
 220                 }                                                       \
 221         }                                                               \
 222         else {                                                          \
 223                 __pu_err = -EFAULT;                                     \
 224         }                                                               \
 225         __pu_err;                                                       \
 226 })
 227
 228 #define __put_user_asm(INSN)                                    \
 229 ({                                                              \
 230         asm volatile(                                           \
 231                 "1:\n"                                          \
 232                 "       mov"INSN"       %1,%2\n"                \
 233                 "       mov             0,%0\n"                 \
 234                 "2:\n"                                          \
 235                 "       .section        .fixup,\"ax\"\n"        \
 236                 "3:\n"                                          \
 237                 "       mov             %3,%0\n"                \
 238                 "       jmp             2b\n"                   \
 239                 "       .previous\n"                            \
 240                 "       .section        __ex_table,\"a\"\n"     \
 241                 "       .balign         4\n"                    \
 242                 "       .long           1b, 3b\n"               \
 243                 "       .previous"                              \
 244                 : "=&r" (__pu_err)                              \
 245                 : "r" (__pu_val.val), "m" (__m(__pu_addr)),     \
 246                   "i" (-EFAULT)                                 \
 247                 );                                              \
 248 })
 249
 250 #define __put_user_asm8()                                               \
 251 ({                                                                      \
 252         asm volatile(                                                   \
 253                 "1:     mov             %1,%3           \n"             \
 254                 "2:     mov             %2,%4           \n"             \
 255                 "       mov             0,%0            \n"             \
 256                 "3:                                     \n"             \
 257                 "       .section        .fixup,\"ax\"   \n"             \
 258                 "4:                                     \n"             \
 259                 "       mov             %5,%0           \n"             \
 260                 "       jmp             3b              \n"             \
 261                 "       .previous                       \n"             \
 262                 "       .section        __ex_table,\"a\"\n"             \
 263                 "       .balign         4               \n"             \
 264                 "       .long           1b, 4b          \n"             \
 265                 "       .long           2b, 4b          \n"             \
 266                 "       .previous                       \n"             \
 267                 : "=&r" (__pu_err)                                      \
 268                 : "r" (__pu_val.bits[0]), "r" (__pu_val.bits[1]),       \
 269                   "m" (__m(__pu_addr)), "m" (__m(__pu_addr+4)),         \
 270                   "i" (-EFAULT)                                         \
 271                 );                                                      \
 272 })
 273
 274 extern int __put_user_unknown(void);
 275
 276
 277 /*
 278  * Copy To/From Userspace
 279  */
 280 /* Generic arbitrary sized copy.  */
 281 #define __copy_user(to, from, size)                                     \
 282 do {                                                                    \
 283         if (size) {                                                     \
 284                 void *__to = to;                                        \
 285                 const void *__from = from;                              \
 286                 int w;                                                  \
 287                 asm volatile(                                           \
 288                         "0:     movbu   (%0),%3;\n"                     \
 289                         "1:     movbu   %3,(%1);\n"                     \
 290                         "       inc     %0;\n"                          \
 291                         "       inc     %1;\n"                          \
 292                         "       add     -1,%2;\n"                       \
 293                         "       bne     0b;\n"                          \
 294                         "2:\n"                                          \
 295                         "       .section .fixup,\"ax\"\n"               \
 296                         "3:     jmp     2b\n"                           \
 297                         "       .previous\n"                            \
 298                         "       .section __ex_table,\"a\"\n"            \
 299                         "       .balign 4\n"                            \
 300                         "       .long   0b,3b\n"                        \
 301                         "       .long   1b,3b\n"                        \
 302                         "       .previous\n"                            \
 303                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 304                         : "0"(__from), "1"(__to), "2"(size)             \
 305                         : "cc", "memory");                              \
 306         }                                                               \
 307 } while (0)
 308
 309 #define __copy_user_zeroing(to, from, size)                             \
 310 do {                                                                    \
 311         if (size) {                                                     \
 312                 void *__to = to;                                        \
 313                 const void *__from = from;                              \
 314                 int w;                                                  \
 315                 asm volatile(                                           \
 316                         "0:     movbu   (%0),%3;\n"                     \
 317                         "1:     movbu   %3,(%1);\n"                     \
 318                         "       inc     %0;\n"                          \
 319                         "       inc     %1;\n"                          \
 320                         "       add     -1,%2;\n"                       \
 321                         "       bne     0b;\n"                          \
 322                         "2:\n"                                          \
 323                         "       .section .fixup,\"ax\"\n"               \
 324                         "3:\n"                                          \
 325                         "       mov     %2,%0\n"                        \
 326                         "       clr     %3\n"                           \
 327                         "4:     movbu   %3,(%1);\n"                     \
 328                         "       inc     %1;\n"                          \
 329                         "       add     -1,%2;\n"                       \
 330                         "       bne     4b;\n"                          \
 331                         "       mov     %0,%2\n"                        \
 332                         "       jmp     2b\n"                           \
 333                         "       .previous\n"                            \
 334                         "       .section __ex_table,\"a\"\n"            \
 335                         "       .balign 4\n"                            \
 336                         "       .long   0b,3b\n"                        \
 337                         "       .long   1b,3b\n"                        \
 338                         "       .previous\n"                            \
 339                         : "=a"(__from), "=a"(__to), "=r"(size), "=&r"(w)\
 340                         : "0"(__from), "1"(__to), "2"(size)             \
 341                         : "cc", "memory");                              \
 342         }                                                               \
 343 } while (0)
 344
 345 /* We let the __ versions of copy_from/to_user inline, because they're often
 346  * used in fast paths and have only a small space overhead.
 347  */
 348 static inline
 349 unsigned long __generic_copy_from_user_nocheck(void *to, const void *from,
 350                                                unsigned long n)
 351 {
 352         __copy_user_zeroing(to, from, n);
 353         return n;
 354 }
 355
 356 static inline
 357 unsigned long __generic_copy_to_user_nocheck(void *to, const void *from,
 358                                              unsigned long n)
 359 {
 360         __copy_user(to, from, n);
 361         return n;
 362 }
 363
 364
 365 #if 0
 366 #error "don't use - these macros don't increment to & from pointers"
 367 /* Optimize just a little bit when we know the size of the move. */
 368 #define __constant_copy_user(to, from, size)    \
 369 do {                                            \
 370         asm volatile(                           \
 371                 "       mov %0,a0;\n"           \
 372                 "0:     movbu (%1),d3;\n"       \
 373                 "1:     movbu d3,(%2);\n"       \
 374                 "       add -1,a0;\n"           \
 375                 "       bne 0b;\n"              \
 376                 "2:;"                           \
 377                 ".section .fixup,\"ax\"\n"      \
 378                 "3:     jmp 2b\n"               \
 379                 ".previous\n"                   \
 380                 ".section __ex_table,\"a\"\n"   \
 381                 "       .balign 4\n"            \
 382                 "       .long 0b,3b\n"          \
 383                 "       .long 1b,3b\n"          \
 384                 ".previous"                     \
 385                 :                               \
 386                 : "d"(size), "d"(to), "d"(from) \
 387                 : "d3", "a0");                  \
 388 } while (0)
 389
 390 /* Optimize just a little bit when we know the size of the move. */
 391 #define __constant_copy_user_zeroing(to, from, size)    \
 392 do {                                                    \
 393         asm volatile(                                   \
 394                 "       mov %0,a0;\n"                   \
 395                 "0:     movbu (%1),d3;\n"               \
 396                 "1:     movbu d3,(%2);\n"               \
 397                 "       add -1,a0;\n"                   \
 398                 "       bne 0b;\n"                      \
 399                 "2:;"                                   \
 400                 ".section .fixup,\"ax\"\n"              \
 401                 "3:     jmp 2b\n"                       \
 402                 ".previous\n"                           \
 403                 ".section __ex_table,\"a\"\n"           \
 404                 "       .balign 4\n"                    \
 405                 "       .long 0b,3b\n"                  \
 406                 "       .long 1b,3b\n"                  \
 407                 ".previous"                             \
 408                 :                                       \
 409                 : "d"(size), "d"(to), "d"(from)         \
 410                 : "d3", "a0");                          \
 411 } while (0)
 412
 413 static inline
 414 unsigned long __constant_copy_to_user(void *to, const void *from,
 415                                       unsigned long n)
 416 {
 417         if (access_ok(VERIFY_WRITE, to, n))
 418                 __constant_copy_user(to, from, n);
 419         return n;
 420 }
 421
 422 static inline
 423 unsigned long __constant_copy_from_user(void *to, const void *from,
 424                                         unsigned long n)
 425 {
 426         if (access_ok(VERIFY_READ, from, n))
 427                 __constant_copy_user_zeroing(to, from, n);
 428         return n;
 429 }
 430
 431 static inline
 432 unsigned long __constant_copy_to_user_nocheck(void *to, const void *from,
 433                                               unsigned long n)
 434 {
 435         __constant_copy_user(to, from, n);
 436         return n;
 437 }
 438
 439 static inline
 440 unsigned long __constant_copy_from_user_nocheck(void *to, const void *from,
 441                                                 unsigned long n)
 442 {
 443         __constant_copy_user_zeroing(to, from, n);
 444         return n;
 445 }
 446 #endif
 447
 448 extern unsigned long __generic_copy_to_user(void __user *, const void *,
 449                                             unsigned long);
 450 extern unsigned long __generic_copy_from_user(void *, const void __user *,
 451                                               unsigned long);
 452
 453 #define __copy_to_user_inatomic(to, from, n) \
 454         __generic_copy_to_user_nocheck((to), (from), (n))
 455 #define __copy_from_user_inatomic(to, from, n) \
 456         __generic_copy_from_user_nocheck((to), (from), (n))
 457
 458 #define __copy_to_user(to, from, n)                     \
 459 ({                                                      \
 460         might_fault();                                  \
 461         __copy_to_user_inatomic((to), (from), (n));     \
 462 })
 463
 464 #define __copy_from_user(to, from, n)                   \
 465 ({                                                      \
 466         might_fault();                                  \
 467         __copy_from_user_inatomic((to), (from), (n));   \
 468 })
 469
 470
 471 #define copy_to_user(to, from, n)   __generic_copy_to_user((to), (from), (n))
 472 #define copy_from_user(to, from, n) __generic_copy_from_user((to), (from), (n))
 473
 474 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 475 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 476 extern long strnlen_user(const char __user *str, long n);
 477 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
 478 extern unsigned long clear_user(void __user *mem, unsigned long len);
 479 extern unsigned long __clear_user(void __user *mem, unsigned long len);
 480
 481 #endif /* _ASM_UACCESS_H */