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