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   1 /* $Id: uaccess.h,v 1.11 2003/10/13 07:21:20 lethal Exp $
   2  *
   3  * User space memory access functions
   4  *
   5  * Copyright (C) 1999, 2002  Niibe Yutaka
   6  * Copyright (C) 2003  Paul Mundt
   7  *
   8  *  Based on:
   9  *     MIPS implementation version 1.15 by
  10  *              Copyright (C) 1996, 1997, 1998 by Ralf Baechle
  11  *     and i386 version.
  12  */
  13 #ifndef __ASM_SH_UACCESS_H
  14 #define __ASM_SH_UACCESS_H
  15
  16 #include <linux/errno.h>
  17 #include <linux/sched.h>
  18
  19 #define VERIFY_READ    0
  20 #define VERIFY_WRITE   1
  21
  22 /*
  23  * The fs value determines whether argument validity checking should be
  24  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  25  * get_fs() == KERNEL_DS, checking is bypassed.
  26  *
  27  * For historical reasons (Data Segment Register?), these macros are misnamed.
  28  */
  29
  30 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  31
  32 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFFUL)
  33 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  34
  35 #define segment_eq(a,b) ((a).seg == (b).seg)
  36
  37 #define get_ds()        (KERNEL_DS)
  38
  39 #if !defined(CONFIG_MMU)
  40 /* NOMMU is always true */
  41 #define __addr_ok(addr) (1)
  42
  43 static inline mm_segment_t get_fs(void)
  44 {
  45         return USER_DS;
  46 }
  47
  48 static inline void set_fs(mm_segment_t s)
  49 {
  50 }
  51
  52 /*
  53  * __access_ok: Check if address with size is OK or not.
  54  *
  55  * If we don't have an MMU (or if its disabled) the only thing we really have
  56  * to look out for is if the address resides somewhere outside of what
  57  * available RAM we have.
  58  *
  59  * TODO: This check could probably also stand to be restricted somewhat more..
  60  * though it still does the Right Thing(tm) for the time being.
  61  */
  62 static inline int __access_ok(unsigned long addr, unsigned long size)
  63 {
  64         extern unsigned long memory_start, memory_end;
  65
  66         return ((addr >= memory_start) && ((addr + size) < memory_end));
  67 }
  68 #else /* CONFIG_MMU */
  69 #define __addr_ok(addr) \
  70         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
  71
  72 #define get_fs()        (current_thread_info()->addr_limit)
  73 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  74
  75 /*
  76  * __access_ok: Check if address with size is OK or not.
  77  *
  78  * We do three checks:
  79  * (1) is it user space?
  80  * (2) addr + size --> carry?
  81  * (3) addr + size >= 0x80000000  (PAGE_OFFSET)
  82  *
  83  * (1) (2) (3) | RESULT
  84  *  0   0   0  |  ok
  85  *  0   0   1  |  ok
  86  *  0   1   0  |  bad
  87  *  0   1   1  |  bad
  88  *  1   0   0  |  ok
  89  *  1   0   1  |  bad
  90  *  1   1   0  |  bad
  91  *  1   1   1  |  bad
  92  */
  93 static inline int __access_ok(unsigned long addr, unsigned long size)
  94 {
  95         unsigned long flag, tmp;
  96
  97         __asm__("stc    r7_bank, %0\n\t"
  98                 "mov.l  @(8,%0), %0\n\t"
  99                 "clrt\n\t"
 100                 "addc   %2, %1\n\t"
 101                 "and    %1, %0\n\t"
 102                 "rotcl  %0\n\t"
 103                 "rotcl  %0\n\t"
 104                 "and    #3, %0"
 105                 : "=&z" (flag), "=r" (tmp)
 106                 : "r" (addr), "1" (size)
 107                 : "t");
 108
 109         return flag == 0;
 110 }
 111 #endif /* CONFIG_MMU */
 112
 113 static inline int access_ok(int type, const void __user *p, unsigned long size)
 114 {
 115         unsigned long addr = (unsigned long)p;
 116         return __access_ok(addr, size);
 117 }
 118
 119 /*
 120  * Uh, these should become the main single-value transfer routines ...
 121  * They automatically use the right size if we just have the right
 122  * pointer type ...
 123  *
 124  * As SuperH uses the same address space for kernel and user data, we
 125  * can just do these as direct assignments.
 126  *
 127  * Careful to not
 128  * (a) re-use the arguments for side effects (sizeof is ok)
 129  * (b) require any knowledge of processes at this stage
 130  */
 131 #define put_user(x,ptr) __put_user_check((x),(ptr),sizeof(*(ptr)))
 132 #define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr)))
 133
 134 /*
 135  * The "__xxx" versions do not do address space checking, useful when
 136  * doing multiple accesses to the same area (the user has to do the
 137  * checks by hand with "access_ok()")
 138  */
 139 #define __put_user(x,ptr) \
 140   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 141 #define __get_user(x,ptr) \
 142   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 143
 144 struct __large_struct { unsigned long buf[100]; };
 145 #define __m(x) (*(struct __large_struct *)(x))
 146
 147 #define __get_user_size(x,ptr,size,retval)                      \
 148 do {                                                            \
 149         retval = 0;                                             \
 150         switch (size) {                                         \
 151         case 1:                                                 \
 152                 __get_user_asm(x, ptr, retval, "b");            \
 153                 break;                                          \
 154         case 2:                                                 \
 155                 __get_user_asm(x, ptr, retval, "w");            \
 156                 break;                                          \
 157         case 4:                                                 \
 158                 __get_user_asm(x, ptr, retval, "l");            \
 159                 break;                                          \
 160         default:                                                \
 161                 __get_user_unknown();                           \
 162                 break;                                          \
 163         }                                                       \
 164 } while (0)
 165
 166 #define __get_user_nocheck(x,ptr,size)                          \
 167 ({                                                              \
 168         long __gu_err, __gu_val;                                \
 169         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 170         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 171         __gu_err;                                               \
 172 })
 173
 174 #ifdef CONFIG_MMU
 175 #define __get_user_check(x,ptr,size)                            \
 176 ({                                                              \
 177         long __gu_err, __gu_val;                                \
 178         switch (size) {                                         \
 179         case 1:                                                 \
 180                 __get_user_1(__gu_val, (ptr), __gu_err);        \
 181                 break;                                          \
 182         case 2:                                                 \
 183                 __get_user_2(__gu_val, (ptr), __gu_err);        \
 184                 break;                                          \
 185         case 4:                                                 \
 186                 __get_user_4(__gu_val, (ptr), __gu_err);        \
 187                 break;                                          \
 188         default:                                                \
 189                 __get_user_unknown();                           \
 190                 break;                                          \
 191         }                                                       \
 192                                                                 \
 193         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 194         __gu_err;                                               \
 195 })
 196
 197 #define __get_user_1(x,addr,err) ({             \
 198 __asm__("stc    r7_bank, %1\n\t"                \
 199         "mov.l  @(8,%1), %1\n\t"                \
 200         "and    %2, %1\n\t"                     \
 201         "cmp/pz %1\n\t"                         \
 202         "bt/s   1f\n\t"                         \
 203         " mov   #0, %0\n\t"                     \
 204         "0:\n"                                  \
 205         "mov    #-14, %0\n\t"                   \
 206         "bra    2f\n\t"                         \
 207         " mov   #0, %1\n"                       \
 208         "1:\n\t"                                \
 209         "mov.b  @%2, %1\n\t"                    \
 210         "extu.b %1, %1\n"                       \
 211         "2:\n"                                  \
 212         ".section       __ex_table,\"a\"\n\t"   \
 213         ".long  1b, 0b\n\t"                     \
 214         ".previous"                             \
 215         : "=&r" (err), "=&r" (x)                \
 216         : "r" (addr)                            \
 217         : "t");                                 \
 218 })
 219
 220 #define __get_user_2(x,addr,err) ({             \
 221 __asm__("stc    r7_bank, %1\n\t"                \
 222         "mov.l  @(8,%1), %1\n\t"                \
 223         "and    %2, %1\n\t"                     \
 224         "cmp/pz %1\n\t"                         \
 225         "bt/s   1f\n\t"                         \
 226         " mov   #0, %0\n\t"                     \
 227         "0:\n"                                  \
 228         "mov    #-14, %0\n\t"                   \
 229         "bra    2f\n\t"                         \
 230         " mov   #0, %1\n"                       \
 231         "1:\n\t"                                \
 232         "mov.w  @%2, %1\n\t"                    \
 233         "extu.w %1, %1\n"                       \
 234         "2:\n"                                  \
 235         ".section       __ex_table,\"a\"\n\t"   \
 236         ".long  1b, 0b\n\t"                     \
 237         ".previous"                             \
 238         : "=&r" (err), "=&r" (x)                \
 239         : "r" (addr)                            \
 240         : "t");                                 \
 241 })
 242
 243 #define __get_user_4(x,addr,err) ({             \
 244 __asm__("stc    r7_bank, %1\n\t"                \
 245         "mov.l  @(8,%1), %1\n\t"                \
 246         "and    %2, %1\n\t"                     \
 247         "cmp/pz %1\n\t"                         \
 248         "bt/s   1f\n\t"                         \
 249         " mov   #0, %0\n\t"                     \
 250         "0:\n"                                  \
 251         "mov    #-14, %0\n\t"                   \
 252         "bra    2f\n\t"                         \
 253         " mov   #0, %1\n"                       \
 254         "1:\n\t"                                \
 255         "mov.l  @%2, %1\n\t"                    \
 256         "2:\n"                                  \
 257         ".section       __ex_table,\"a\"\n\t"   \
 258         ".long  1b, 0b\n\t"                     \
 259         ".previous"                             \
 260         : "=&r" (err), "=&r" (x)                \
 261         : "r" (addr)                            \
 262         : "t");                                 \
 263 })
 264 #else /* CONFIG_MMU */
 265 #define __get_user_check(x,ptr,size)                                    \
 266 ({                                                                      \
 267         long __gu_err, __gu_val;                                        \
 268         if (__access_ok((unsigned long)(ptr), (size))) {                \
 269                 __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 270                 (x) = (__typeof__(*(ptr)))__gu_val;                     \
 271         } else                                                          \
 272                 __gu_err = -EFAULT;                                     \
 273         __gu_err;                                                       \
 274 })
 275 #endif
 276
 277 #define __get_user_asm(x, addr, err, insn) \
 278 ({ \
 279 __asm__ __volatile__( \
 280         "1:\n\t" \
 281         "mov." insn "   %2, %1\n\t" \
 282         "mov    #0, %0\n" \
 283         "2:\n" \
 284         ".section       .fixup,\"ax\"\n" \
 285         "3:\n\t" \
 286         "mov    #0, %1\n\t" \
 287         "mov.l  4f, %0\n\t" \
 288         "jmp    @%0\n\t" \
 289         " mov   %3, %0\n" \
 290         "4:     .long   2b\n\t" \
 291         ".previous\n" \
 292         ".section       __ex_table,\"a\"\n\t" \
 293         ".long  1b, 3b\n\t" \
 294         ".previous" \
 295         :"=&r" (err), "=&r" (x) \
 296         :"m" (__m(addr)), "i" (-EFAULT)); })
 297
 298 extern void __get_user_unknown(void);
 299
 300 #define __put_user_size(x,ptr,size,retval)              \
 301 do {                                                    \
 302         retval = 0;                                     \
 303         switch (size) {                                 \
 304         case 1:                                         \
 305                 __put_user_asm(x, ptr, retval, "b");    \
 306                 break;                                  \
 307         case 2:                                         \
 308                 __put_user_asm(x, ptr, retval, "w");    \
 309                 break;                                  \
 310         case 4:                                         \
 311                 __put_user_asm(x, ptr, retval, "l");    \
 312                 break;                                  \
 313         case 8:                                         \
 314                 __put_user_u64(x, ptr, retval);         \
 315                 break;                                  \
 316         default:                                        \
 317                 __put_user_unknown();                   \
 318         }                                               \
 319 } while (0)
 320
 321 #define __put_user_nocheck(x,ptr,size)                  \
 322 ({                                                      \
 323         long __pu_err;                                  \
 324         __put_user_size((x),(ptr),(size),__pu_err);     \
 325         __pu_err;                                       \
 326 })
 327
 328 #define __put_user_check(x,ptr,size)                            \
 329 ({                                                              \
 330         long __pu_err = -EFAULT;                                \
 331         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 332                                                                 \
 333         if (__access_ok((unsigned long)__pu_addr,size))         \
 334                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 335         __pu_err;                                               \
 336 })
 337
 338 #define __put_user_asm(x, addr, err, insn) \
 339 ({ \
 340 __asm__ __volatile__( \
 341         "1:\n\t" \
 342         "mov." insn "   %1, %2\n\t" \
 343         "mov    #0, %0\n" \
 344         "2:\n" \
 345         ".section       .fixup,\"ax\"\n" \
 346         "3:\n\t" \
 347         "nop\n\t" \
 348         "mov.l  4f, %0\n\t" \
 349         "jmp    @%0\n\t" \
 350         "mov    %3, %0\n" \
 351         "4:     .long   2b\n\t" \
 352         ".previous\n" \
 353         ".section       __ex_table,\"a\"\n\t" \
 354         ".long  1b, 3b\n\t" \
 355         ".previous" \
 356         :"=&r" (err) \
 357         :"r" (x), "m" (__m(addr)), "i" (-EFAULT) \
 358         :"memory"); })
 359
 360 #if defined(__LITTLE_ENDIAN__)
 361 #define __put_user_u64(val,addr,retval) \
 362 ({ \
 363 __asm__ __volatile__( \
 364         "1:\n\t" \
 365         "mov.l  %R1,%2\n\t" \
 366         "mov.l  %S1,%T2\n\t" \
 367         "mov    #0,%0\n" \
 368         "2:\n" \
 369         ".section       .fixup,\"ax\"\n" \
 370         "3:\n\t" \
 371         "nop\n\t" \
 372         "mov.l  4f,%0\n\t" \
 373         "jmp    @%0\n\t" \
 374         " mov   %3,%0\n" \
 375         "4:     .long   2b\n\t" \
 376         ".previous\n" \
 377         ".section       __ex_table,\"a\"\n\t" \
 378         ".long  1b, 3b\n\t" \
 379         ".previous" \
 380         : "=r" (retval) \
 381         : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \
 382         : "memory"); })
 383 #else
 384 #define __put_user_u64(val,addr,retval) \
 385 ({ \
 386 __asm__ __volatile__( \
 387         "1:\n\t" \
 388         "mov.l  %S1,%2\n\t" \
 389         "mov.l  %R1,%T2\n\t" \
 390         "mov    #0,%0\n" \
 391         "2:\n" \
 392         ".section       .fixup,\"ax\"\n" \
 393         "3:\n\t" \
 394         "nop\n\t" \
 395         "mov.l  4f,%0\n\t" \
 396         "jmp    @%0\n\t" \
 397         " mov   %3,%0\n" \
 398         "4:     .long   2b\n\t" \
 399         ".previous\n" \
 400         ".section       __ex_table,\"a\"\n\t" \
 401         ".long  1b, 3b\n\t" \
 402         ".previous" \
 403         : "=r" (retval) \
 404         : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \
 405         : "memory"); })
 406 #endif
 407
 408 extern void __put_user_unknown(void);
 409 \f
 410 /* Generic arbitrary sized copy.  */
 411 /* Return the number of bytes NOT copied */
 412 extern __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
 413
 414 #define copy_to_user(to,from,n) ({ \
 415 void *__copy_to = (void *) (to); \
 416 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 417 __kernel_size_t __copy_res; \
 418 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
 419 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
 420 } else __copy_res = __copy_size; \
 421 __copy_res; })
 422
 423 #define __copy_to_user(to,from,n)               \
 424         __copy_user((void *)(to),               \
 425                     (void *)(from), n)
 426
 427 #define __copy_to_user_inatomic __copy_to_user
 428 #define __copy_from_user_inatomic __copy_from_user
 429
 430
 431 #define copy_from_user(to,from,n) ({ \
 432 void *__copy_to = (void *) (to); \
 433 void *__copy_from = (void *) (from); \
 434 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 435 __kernel_size_t __copy_res; \
 436 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
 437 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
 438 } else __copy_res = __copy_size; \
 439 __copy_res; })
 440
 441 #define __copy_from_user(to,from,n)             \
 442         __copy_user((void *)(to),               \
 443                     (void *)(from), n)
 444
 445 /*
 446  * Clear the area and return remaining number of bytes
 447  * (on failure.  Usually it's 0.)
 448  */
 449 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
 450
 451 #define clear_user(addr,n) ({ \
 452 void * __cl_addr = (addr); \
 453 unsigned long __cl_size = (n); \
 454 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
 455 __cl_size = __clear_user(__cl_addr, __cl_size); \
 456 __cl_size; })
 457
 458 static __inline__ int
 459 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
 460 {
 461         __kernel_size_t res;
 462         unsigned long __dummy, _d, _s;
 463
 464         __asm__ __volatile__(
 465                 "9:\n"
 466                 "mov.b  @%2+, %1\n\t"
 467                 "cmp/eq #0, %1\n\t"
 468                 "bt/s   2f\n"
 469                 "1:\n"
 470                 "mov.b  %1, @%3\n\t"
 471                 "dt     %7\n\t"
 472                 "bf/s   9b\n\t"
 473                 " add   #1, %3\n\t"
 474                 "2:\n\t"
 475                 "sub    %7, %0\n"
 476                 "3:\n"
 477                 ".section .fixup,\"ax\"\n"
 478                 "4:\n\t"
 479                 "mov.l  5f, %1\n\t"
 480                 "jmp    @%1\n\t"
 481                 " mov   %8, %0\n\t"
 482                 ".balign 4\n"
 483                 "5:     .long 3b\n"
 484                 ".previous\n"
 485                 ".section __ex_table,\"a\"\n"
 486                 "       .balign 4\n"
 487                 "       .long 9b,4b\n"
 488                 ".previous"
 489                 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d)
 490                 : "0" (__count), "2" (__src), "3" (__dest), "r" (__count),
 491                   "i" (-EFAULT)
 492                 : "memory", "t");
 493
 494         return res;
 495 }
 496
 497 #define strncpy_from_user(dest,src,count) ({ \
 498 unsigned long __sfu_src = (unsigned long) (src); \
 499 int __sfu_count = (int) (count); \
 500 long __sfu_res = -EFAULT; \
 501 if(__access_ok(__sfu_src, __sfu_count)) { \
 502 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
 503 } __sfu_res; })
 504
 505 /*
 506  * Return the size of a string (including the ending 0!)
 507  */
 508 static __inline__ long __strnlen_user(const char __user *__s, long __n)
 509 {
 510         unsigned long res;
 511         unsigned long __dummy;
 512
 513         __asm__ __volatile__(
 514                 "9:\n"
 515                 "cmp/eq %4, %0\n\t"
 516                 "bt     2f\n"
 517                 "1:\t"
 518                 "mov.b  @(%0,%3), %1\n\t"
 519                 "tst    %1, %1\n\t"
 520                 "bf/s   9b\n\t"
 521                 " add   #1, %0\n"
 522                 "2:\n"
 523                 ".section .fixup,\"ax\"\n"
 524                 "3:\n\t"
 525                 "mov.l  4f, %1\n\t"
 526                 "jmp    @%1\n\t"
 527                 " mov   #0, %0\n"
 528                 ".balign 4\n"
 529                 "4:     .long 2b\n"
 530                 ".previous\n"
 531                 ".section __ex_table,\"a\"\n"
 532                 "       .balign 4\n"
 533                 "       .long 1b,3b\n"
 534                 ".previous"
 535                 : "=z" (res), "=&r" (__dummy)
 536                 : "0" (0), "r" (__s), "r" (__n)
 537                 : "t");
 538         return res;
 539 }
 540
 541 static __inline__ long strnlen_user(const char __user *s, long n)
 542 {
 543         if (!__addr_ok(s))
 544                 return 0;
 545         else
 546                 return __strnlen_user(s, n);
 547 }
 548
 549 #define strlen_user(str)        strnlen_user(str, ~0UL >> 1)
 550
 551 /*
 552  * The exception table consists of pairs of addresses: the first is the
 553  * address of an instruction that is allowed to fault, and the second is
 554  * the address at which the program should continue.  No registers are
 555  * modified, so it is entirely up to the continuation code to figure out
 556  * what to do.
 557  *
 558  * All the routines below use bits of fixup code that are out of line
 559  * with the main instruction path.  This means when everything is well,
 560  * we don't even have to jump over them.  Further, they do not intrude
 561  * on our cache or tlb entries.
 562  */
 563
 564 struct exception_table_entry
 565 {
 566         unsigned long insn, fixup;
 567 };
 568
 569 extern int fixup_exception(struct pt_regs *regs);
 570
 571 #endif /* __ASM_SH_UACCESS_H */