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