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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 /*
  20  * NOTE: Macro/functions in this file depends on threads_info.h implementation.
  21  * Assumes:
  22  * TI_FLAGS == 8
  23  * TIF_USERSPACE == 31
  24  * USER_ADDR_LIMIT == 0x80000000
  25  */
  26
  27 #define VERIFY_READ    0
  28 #define VERIFY_WRITE   1
  29
  30 typedef struct {
  31         unsigned int is_user_space;
  32 } mm_segment_t;
  33
  34 /*
  35  * The fs value determines whether argument validity checking should be
  36  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  37  * get_fs() == KERNEL_DS, checking is bypassed.
  38  *
  39  * For historical reasons (Data Segment Register?), these macros are misnamed.
  40  */
  41
  42 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  43 #define segment_eq(a,b) ((a).is_user_space == (b).is_user_space)
  44
  45 #define USER_ADDR_LIMIT 0x80000000
  46
  47 #define KERNEL_DS       MAKE_MM_SEG(0)
  48 #define USER_DS         MAKE_MM_SEG(1)
  49
  50 #define get_ds()        (KERNEL_DS)
  51
  52 #if !defined(CONFIG_MMU)
  53 static inline mm_segment_t get_fs(void)
  54 {
  55         return USER_DS;
  56 }
  57
  58 static inline void set_fs(mm_segment_t s)
  59 {
  60 }
  61
  62 /*
  63  * __access_ok: Check if address with size is OK or not.
  64  *
  65  * If we don't have an MMU (or if its disabled) the only thing we really have
  66  * to look out for is if the address resides somewhere outside of what
  67  * available RAM we have.
  68  *
  69  * TODO: This check could probably also stand to be restricted somewhat more..
  70  * though it still does the Right Thing(tm) for the time being.
  71  */
  72 static inline int __access_ok(unsigned long addr, unsigned long size)
  73 {
  74         extern unsigned long memory_start, memory_end;
  75
  76         return ((addr >= memory_start) && ((addr + size) < memory_end));
  77 }
  78 #else /* CONFIG_MMU */
  79 static inline mm_segment_t get_fs(void)
  80 {
  81         return MAKE_MM_SEG(test_thread_flag(TIF_USERSPACE));
  82 }
  83
  84 static inline void set_fs(mm_segment_t s)
  85 {
  86         unsigned long ti, flag;
  87         __asm__ __volatile__(
  88                 "stc    r7_bank, %0\n\t"
  89                 "mov.l  @(8,%0), %1\n\t"
  90                 "shal   %1\n\t"
  91                 "cmp/pl %2\n\t"
  92                 "rotcr  %1\n\t"
  93                 "mov.l  %1, @(8,%0)"
  94                 : "=&r" (ti), "=&r" (flag)
  95                 : "r" (s.is_user_space)
  96                 : "t");
  97 /****
  98         if (s.is_user_space)
  99                 set_thread_flag(TIF_USERSPACE);
 100         else
 101                 clear_thread_flag(TIF_USERSPACE);
 102 ****/
 103 }
 104
 105 /*
 106  * __access_ok: Check if address with size is OK or not.
 107  *
 108  * We do three checks:
 109  * (1) is it user space?
 110  * (2) addr + size --> carry?
 111  * (3) addr + size >= 0x80000000  (USER_ADDR_LIMIT)
 112  *
 113  * (1) (2) (3) | RESULT
 114  *  0   0   0  |  ok
 115  *  0   0   1  |  ok
 116  *  0   1   0  |  bad
 117  *  0   1   1  |  bad
 118  *  1   0   0  |  ok
 119  *  1   0   1  |  bad
 120  *  1   1   0  |  bad
 121  *  1   1   1  |  bad
 122  */
 123 static inline int __access_ok(unsigned long addr, unsigned long size)
 124 {
 125         unsigned long flag, tmp;
 126
 127         __asm__("stc    r7_bank, %0\n\t"
 128                 "mov.l  @(8,%0), %0\n\t"
 129                 "clrt\n\t"
 130                 "addc   %2, %1\n\t"
 131                 "and    %1, %0\n\t"
 132                 "rotcl  %0\n\t"
 133                 "rotcl  %0\n\t"
 134                 "and    #3, %0"
 135                 : "=&z" (flag), "=r" (tmp)
 136                 : "r" (addr), "1" (size)
 137                 : "t");
 138
 139         return flag == 0;
 140 }
 141 #endif /* CONFIG_MMU */
 142
 143 static inline int access_ok(int type, const void __user *p, unsigned long size)
 144 {
 145         unsigned long addr = (unsigned long)p;
 146         return __access_ok(addr, size);
 147 }
 148
 149 /* this function will go away soon - use access_ok() instead */
 150 static inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
 151 {
 152         return access_ok(type,addr,size) ? 0 : -EFAULT;
 153 }
 154
 155 /*
 156  * Uh, these should become the main single-value transfer routines ...
 157  * They automatically use the right size if we just have the right
 158  * pointer type ...
 159  *
 160  * As SuperH uses the same address space for kernel and user data, we
 161  * can just do these as direct assignments.
 162  *
 163  * Careful to not
 164  * (a) re-use the arguments for side effects (sizeof is ok)
 165  * (b) require any knowledge of processes at this stage
 166  */
 167 #define put_user(x,ptr) __put_user_check((x),(ptr),sizeof(*(ptr)))
 168 #define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr)))
 169
 170 /*
 171  * The "__xxx" versions do not do address space checking, useful when
 172  * doing multiple accesses to the same area (the user has to do the
 173  * checks by hand with "access_ok()")
 174  */
 175 #define __put_user(x,ptr) \
 176   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 177 #define __get_user(x,ptr) \
 178   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 179
 180 struct __large_struct { unsigned long buf[100]; };
 181 #define __m(x) (*(struct __large_struct *)(x))
 182
 183 #define __get_user_size(x,ptr,size,retval)                      \
 184 do {                                                            \
 185         retval = 0;                                             \
 186         switch (size) {                                         \
 187         case 1:                                                 \
 188                 __get_user_asm(x, ptr, retval, "b");            \
 189                 break;                                          \
 190         case 2:                                                 \
 191                 __get_user_asm(x, ptr, retval, "w");            \
 192                 break;                                          \
 193         case 4:                                                 \
 194                 __get_user_asm(x, ptr, retval, "l");            \
 195                 break;                                          \
 196         default:                                                \
 197                 __get_user_unknown();                           \
 198                 break;                                          \
 199         }                                                       \
 200 } while (0)
 201
 202 #define __get_user_nocheck(x,ptr,size)                          \
 203 ({                                                              \
 204         long __gu_err, __gu_val;                                \
 205         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 206         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 207         __gu_err;                                               \
 208 })
 209
 210 #define __get_user_check(x,ptr,size)                            \
 211 ({                                                              \
 212         long __gu_err, __gu_val;                                \
 213         switch (size) {                                         \
 214         case 1:                                                 \
 215                 __get_user_1(__gu_val, (ptr), __gu_err);        \
 216                 break;                                          \
 217         case 2:                                                 \
 218                 __get_user_2(__gu_val, (ptr), __gu_err);        \
 219                 break;                                          \
 220         case 4:                                                 \
 221                 __get_user_4(__gu_val, (ptr), __gu_err);        \
 222                 break;                                          \
 223         default:                                                \
 224                 __get_user_unknown();                           \
 225                 break;                                          \
 226         }                                                       \
 227                                                                 \
 228         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 229         __gu_err;                                               \
 230 })
 231
 232 #define __get_user_1(x,addr,err) ({             \
 233 __asm__("stc    r7_bank, %1\n\t"                \
 234         "mov.l  @(8,%1), %1\n\t"                \
 235         "and    %2, %1\n\t"                     \
 236         "cmp/pz %1\n\t"                         \
 237         "bt/s   1f\n\t"                         \
 238         " mov   #0, %0\n\t"                     \
 239         "0:\n"                                  \
 240         "mov    #-14, %0\n\t"                   \
 241         "bra    2f\n\t"                         \
 242         " mov   #0, %1\n"                       \
 243         "1:\n\t"                                \
 244         "mov.b  @%2, %1\n\t"                    \
 245         "extu.b %1, %1\n"                       \
 246         "2:\n"                                  \
 247         ".section       __ex_table,\"a\"\n\t"   \
 248         ".long  1b, 0b\n\t"                     \
 249         ".previous"                             \
 250         : "=&r" (err), "=&r" (x)                \
 251         : "r" (addr)                            \
 252         : "t");                                 \
 253 })
 254
 255 #define __get_user_2(x,addr,err) ({             \
 256 __asm__("stc    r7_bank, %1\n\t"                \
 257         "mov.l  @(8,%1), %1\n\t"                \
 258         "and    %2, %1\n\t"                     \
 259         "cmp/pz %1\n\t"                         \
 260         "bt/s   1f\n\t"                         \
 261         " mov   #0, %0\n\t"                     \
 262         "0:\n"                                  \
 263         "mov    #-14, %0\n\t"                   \
 264         "bra    2f\n\t"                         \
 265         " mov   #0, %1\n"                       \
 266         "1:\n\t"                                \
 267         "mov.w  @%2, %1\n\t"                    \
 268         "extu.w %1, %1\n"                       \
 269         "2:\n"                                  \
 270         ".section       __ex_table,\"a\"\n\t"   \
 271         ".long  1b, 0b\n\t"                     \
 272         ".previous"                             \
 273         : "=&r" (err), "=&r" (x)                \
 274         : "r" (addr)                            \
 275         : "t");                                 \
 276 })
 277
 278 #define __get_user_4(x,addr,err) ({             \
 279 __asm__("stc    r7_bank, %1\n\t"                \
 280         "mov.l  @(8,%1), %1\n\t"                \
 281         "and    %2, %1\n\t"                     \
 282         "cmp/pz %1\n\t"                         \
 283         "bt/s   1f\n\t"                         \
 284         " mov   #0, %0\n\t"                     \
 285         "0:\n"                                  \
 286         "mov    #-14, %0\n\t"                   \
 287         "bra    2f\n\t"                         \
 288         " mov   #0, %1\n"                       \
 289         "1:\n\t"                                \
 290         "mov.l  @%2, %1\n\t"                    \
 291         "2:\n"                                  \
 292         ".section       __ex_table,\"a\"\n\t"   \
 293         ".long  1b, 0b\n\t"                     \
 294         ".previous"                             \
 295         : "=&r" (err), "=&r" (x)                \
 296         : "r" (addr)                            \
 297         : "t");                                 \
 298 })
 299
 300 #define __get_user_asm(x, addr, err, insn) \
 301 ({ \
 302 __asm__ __volatile__( \
 303         "1:\n\t" \
 304         "mov." insn "   %2, %1\n\t" \
 305         "mov    #0, %0\n" \
 306         "2:\n" \
 307         ".section       .fixup,\"ax\"\n" \
 308         "3:\n\t" \
 309         "mov    #0, %1\n\t" \
 310         "mov.l  4f, %0\n\t" \
 311         "jmp    @%0\n\t" \
 312         " mov   %3, %0\n" \
 313         "4:     .long   2b\n\t" \
 314         ".previous\n" \
 315         ".section       __ex_table,\"a\"\n\t" \
 316         ".long  1b, 3b\n\t" \
 317         ".previous" \
 318         :"=&r" (err), "=&r" (x) \
 319         :"m" (__m(addr)), "i" (-EFAULT)); })
 320
 321 extern void __get_user_unknown(void);
 322
 323 #define __put_user_size(x,ptr,size,retval)              \
 324 do {                                                    \
 325         retval = 0;                                     \
 326         switch (size) {                                 \
 327         case 1:                                         \
 328                 __put_user_asm(x, ptr, retval, "b");    \
 329                 break;                                  \
 330         case 2:                                         \
 331                 __put_user_asm(x, ptr, retval, "w");    \
 332                 break;                                  \
 333         case 4:                                         \
 334                 __put_user_asm(x, ptr, retval, "l");    \
 335                 break;                                  \
 336         case 8:                                         \
 337                 __put_user_u64(x, ptr, retval);         \
 338                 break;                                  \
 339         default:                                        \
 340                 __put_user_unknown();                   \
 341         }                                               \
 342 } while (0)
 343
 344 #define __put_user_nocheck(x,ptr,size)                  \
 345 ({                                                      \
 346         long __pu_err;                                  \
 347         __put_user_size((x),(ptr),(size),__pu_err);     \
 348         __pu_err;                                       \
 349 })
 350
 351 #define __put_user_check(x,ptr,size)                            \
 352 ({                                                              \
 353         long __pu_err = -EFAULT;                                \
 354         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 355                                                                 \
 356         if (__access_ok((unsigned long)__pu_addr,size))         \
 357                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 358         __pu_err;                                               \
 359 })
 360
 361 #define __put_user_asm(x, addr, err, insn) \
 362 ({ \
 363 __asm__ __volatile__( \
 364         "1:\n\t" \
 365         "mov." insn "   %1, %2\n\t" \
 366         "mov    #0, %0\n" \
 367         "2:\n" \
 368         ".section       .fixup,\"ax\"\n" \
 369         "3:\n\t" \
 370         "nop\n\t" \
 371         "mov.l  4f, %0\n\t" \
 372         "jmp    @%0\n\t" \
 373         "mov    %3, %0\n" \
 374         "4:     .long   2b\n\t" \
 375         ".previous\n" \
 376         ".section       __ex_table,\"a\"\n\t" \
 377         ".long  1b, 3b\n\t" \
 378         ".previous" \
 379         :"=&r" (err) \
 380         :"r" (x), "m" (__m(addr)), "i" (-EFAULT) \
 381         :"memory"); })
 382
 383 #if defined(__LITTLE_ENDIAN__)
 384 #define __put_user_u64(val,addr,retval) \
 385 ({ \
 386 __asm__ __volatile__( \
 387         "1:\n\t" \
 388         "mov.l  %R1,%2\n\t" \
 389         "mov.l  %S1,%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 #else
 407 #define __put_user_u64(val,addr,retval) \
 408 ({ \
 409 __asm__ __volatile__( \
 410         "1:\n\t" \
 411         "mov.l  %S1,%2\n\t" \
 412         "mov.l  %R1,%T2\n\t" \
 413         "mov    #0,%0\n" \
 414         "2:\n" \
 415         ".section       .fixup,\"ax\"\n" \
 416         "3:\n\t" \
 417         "nop\n\t" \
 418         "mov.l  4f,%0\n\t" \
 419         "jmp    @%0\n\t" \
 420         " mov   %3,%0\n" \
 421         "4:     .long   2b\n\t" \
 422         ".previous\n" \
 423         ".section       __ex_table,\"a\"\n\t" \
 424         ".long  1b, 3b\n\t" \
 425         ".previous" \
 426         : "=r" (retval) \
 427         : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \
 428         : "memory"); })
 429 #endif
 430
 431 extern void __put_user_unknown(void);
 432 \f
 433 /* Generic arbitrary sized copy.  */
 434 /* Return the number of bytes NOT copied */
 435 extern __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
 436
 437 #define copy_to_user(to,from,n) ({ \
 438 void *__copy_to = (void *) (to); \
 439 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 440 __kernel_size_t __copy_res; \
 441 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
 442 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
 443 } else __copy_res = __copy_size; \
 444 __copy_res; })
 445
 446 #define __copy_to_user(to,from,n)               \
 447         __copy_user((void *)(to),               \
 448                     (void *)(from), n)
 449
 450 #define __copy_to_user_inatomic __copy_to_user
 451 #define __copy_from_user_inatomic __copy_from_user
 452
 453
 454 #define copy_from_user(to,from,n) ({ \
 455 void *__copy_to = (void *) (to); \
 456 void *__copy_from = (void *) (from); \
 457 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 458 __kernel_size_t __copy_res; \
 459 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
 460 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
 461 } else __copy_res = __copy_size; \
 462 __copy_res; })
 463
 464 #define __copy_from_user(to,from,n)             \
 465         __copy_user((void *)(to),               \
 466                     (void *)(from), n)
 467
 468 /*
 469  * Clear the area and return remaining number of bytes
 470  * (on failure.  Usually it's 0.)
 471  */
 472 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
 473
 474 #define clear_user(addr,n) ({ \
 475 void * __cl_addr = (addr); \
 476 unsigned long __cl_size = (n); \
 477 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
 478 __cl_size = __clear_user(__cl_addr, __cl_size); \
 479 __cl_size; })
 480
 481 static __inline__ int
 482 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
 483 {
 484         __kernel_size_t res;
 485         unsigned long __dummy, _d, _s;
 486
 487         __asm__ __volatile__(
 488                 "9:\n"
 489                 "mov.b  @%2+, %1\n\t"
 490                 "cmp/eq #0, %1\n\t"
 491                 "bt/s   2f\n"
 492                 "1:\n"
 493                 "mov.b  %1, @%3\n\t"
 494                 "dt     %7\n\t"
 495                 "bf/s   9b\n\t"
 496                 " add   #1, %3\n\t"
 497                 "2:\n\t"
 498                 "sub    %7, %0\n"
 499                 "3:\n"
 500                 ".section .fixup,\"ax\"\n"
 501                 "4:\n\t"
 502                 "mov.l  5f, %1\n\t"
 503                 "jmp    @%1\n\t"
 504                 " mov   %8, %0\n\t"
 505                 ".balign 4\n"
 506                 "5:     .long 3b\n"
 507                 ".previous\n"
 508                 ".section __ex_table,\"a\"\n"
 509                 "       .balign 4\n"
 510                 "       .long 9b,4b\n"
 511                 ".previous"
 512                 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d)
 513                 : "0" (__count), "2" (__src), "3" (__dest), "r" (__count),
 514                   "i" (-EFAULT)
 515                 : "memory", "t");
 516
 517         return res;
 518 }
 519
 520 #define strncpy_from_user(dest,src,count) ({ \
 521 unsigned long __sfu_src = (unsigned long) (src); \
 522 int __sfu_count = (int) (count); \
 523 long __sfu_res = -EFAULT; \
 524 if(__access_ok(__sfu_src, __sfu_count)) { \
 525 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
 526 } __sfu_res; })
 527
 528 /*
 529  * Return the size of a string (including the ending 0!)
 530  */
 531 static __inline__ long __strnlen_user(const char __user *__s, long __n)
 532 {
 533         unsigned long res;
 534         unsigned long __dummy;
 535
 536         __asm__ __volatile__(
 537                 "9:\n"
 538                 "cmp/eq %4, %0\n\t"
 539                 "bt     2f\n"
 540                 "1:\t"
 541                 "mov.b  @(%0,%3), %1\n\t"
 542                 "tst    %1, %1\n\t"
 543                 "bf/s   9b\n\t"
 544                 " add   #1, %0\n"
 545                 "2:\n"
 546                 ".section .fixup,\"ax\"\n"
 547                 "3:\n\t"
 548                 "mov.l  4f, %1\n\t"
 549                 "jmp    @%1\n\t"
 550                 " mov   %5, %0\n"
 551                 ".balign 4\n"
 552                 "4:     .long 2b\n"
 553                 ".previous\n"
 554                 ".section __ex_table,\"a\"\n"
 555                 "       .balign 4\n"
 556                 "       .long 1b,3b\n"
 557                 ".previous"
 558                 : "=z" (res), "=&r" (__dummy)
 559                 : "0" (0), "r" (__s), "r" (__n), "i" (-EFAULT)
 560                 : "t");
 561         return res;
 562 }
 563
 564 static __inline__ long strnlen_user(const char __user *s, long n)
 565 {
 566         if (!access_ok(VERIFY_READ, s, n))
 567                 return 0;
 568         else
 569                 return __strnlen_user(s, n);
 570 }
 571
 572 static __inline__ long strlen_user(const char __user *s)
 573 {
 574         if (!access_ok(VERIFY_READ, s, 0))
 575                 return 0;
 576         else
 577                 return __strnlen_user(s, ~0UL >> 1);
 578 }
 579
 580 /*
 581  * The exception table consists of pairs of addresses: the first is the
 582  * address of an instruction that is allowed to fault, and the second is
 583  * the address at which the program should continue.  No registers are
 584  * modified, so it is entirely up to the continuation code to figure out
 585  * what to do.
 586  *
 587  * All the routines below use bits of fixup code that are out of line
 588  * with the main instruction path.  This means when everything is well,
 589  * we don't even have to jump over them.  Further, they do not intrude
 590  * on our cache or tlb entries.
 591  */
 592
 593 struct exception_table_entry
 594 {
 595         unsigned long insn, fixup;
 596 };
 597
 598 extern int fixup_exception(struct pt_regs *regs);
 599
 600 #endif /* __ASM_SH_UACCESS_H */