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