include/asm-sh/uaccess.h

   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 /*
 150  * Uh, these should become the main single-value transfer routines ...
 151  * They automatically use the right size if we just have the right
 152  * pointer type ...
 153  *
 154  * As SuperH uses the same address space for kernel and user data, we
 155  * can just do these as direct assignments.
 156  *
 157  * Careful to not
 158  * (a) re-use the arguments for side effects (sizeof is ok)
 159  * (b) require any knowledge of processes at this stage
 160  */
 161 #define put_user(x,ptr) __put_user_check((x),(ptr),sizeof(*(ptr)))
 162 #define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr)))
 163
 164 /*
 165  * The "__xxx" versions do not do address space checking, useful when
 166  * doing multiple accesses to the same area (the user has to do the
 167  * checks by hand with "access_ok()")
 168  */
 169 #define __put_user(x,ptr) \
 170   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 171 #define __get_user(x,ptr) \
 172   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 173
 174 struct __large_struct { unsigned long buf[100]; };
 175 #define __m(x) (*(struct __large_struct *)(x))
 176
 177 #define __get_user_size(x,ptr,size,retval)                      \
 178 do {                                                            \
 179         retval = 0;                                             \
 180         switch (size) {                                         \
 181         case 1:                                                 \
 182                 __get_user_asm(x, ptr, retval, "b");            \
 183                 break;                                          \
 184         case 2:                                                 \
 185                 __get_user_asm(x, ptr, retval, "w");            \
 186                 break;                                          \
 187         case 4:                                                 \
 188                 __get_user_asm(x, ptr, retval, "l");            \
 189                 break;                                          \
 190         default:                                                \
 191                 __get_user_unknown();                           \
 192                 break;                                          \
 193         }                                                       \
 194 } while (0)
 195
 196 #define __get_user_nocheck(x,ptr,size)                          \
 197 ({                                                              \
 198         long __gu_err, __gu_val;                                \
 199         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 200         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 201         __gu_err;                                               \
 202 })
 203
 204 #define __get_user_check(x,ptr,size)                            \
 205 ({                                                              \
 206         long __gu_err, __gu_val;                                \
 207         switch (size) {                                         \
 208         case 1:                                                 \
 209                 __get_user_1(__gu_val, (ptr), __gu_err);        \
 210                 break;                                          \
 211         case 2:                                                 \
 212                 __get_user_2(__gu_val, (ptr), __gu_err);        \
 213                 break;                                          \
 214         case 4:                                                 \
 215                 __get_user_4(__gu_val, (ptr), __gu_err);        \
 216                 break;                                          \
 217         default:                                                \
 218                 __get_user_unknown();                           \
 219                 break;                                          \
 220         }                                                       \
 221                                                                 \
 222         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 223         __gu_err;                                               \
 224 })
 225
 226 #define __get_user_1(x,addr,err) ({             \
 227 __asm__("stc    r7_bank, %1\n\t"                \
 228         "mov.l  @(8,%1), %1\n\t"                \
 229         "and    %2, %1\n\t"                     \
 230         "cmp/pz %1\n\t"                         \
 231         "bt/s   1f\n\t"                         \
 232         " mov   #0, %0\n\t"                     \
 233         "0:\n"                                  \
 234         "mov    #-14, %0\n\t"                   \
 235         "bra    2f\n\t"                         \
 236         " mov   #0, %1\n"                       \
 237         "1:\n\t"                                \
 238         "mov.b  @%2, %1\n\t"                    \
 239         "extu.b %1, %1\n"                       \
 240         "2:\n"                                  \
 241         ".section       __ex_table,\"a\"\n\t"   \
 242         ".long  1b, 0b\n\t"                     \
 243         ".previous"                             \
 244         : "=&r" (err), "=&r" (x)                \
 245         : "r" (addr)                            \
 246         : "t");                                 \
 247 })
 248
 249 #define __get_user_2(x,addr,err) ({             \
 250 __asm__("stc    r7_bank, %1\n\t"                \
 251         "mov.l  @(8,%1), %1\n\t"                \
 252         "and    %2, %1\n\t"                     \
 253         "cmp/pz %1\n\t"                         \
 254         "bt/s   1f\n\t"                         \
 255         " mov   #0, %0\n\t"                     \
 256         "0:\n"                                  \
 257         "mov    #-14, %0\n\t"                   \
 258         "bra    2f\n\t"                         \
 259         " mov   #0, %1\n"                       \
 260         "1:\n\t"                                \
 261         "mov.w  @%2, %1\n\t"                    \
 262         "extu.w %1, %1\n"                       \
 263         "2:\n"                                  \
 264         ".section       __ex_table,\"a\"\n\t"   \
 265         ".long  1b, 0b\n\t"                     \
 266         ".previous"                             \
 267         : "=&r" (err), "=&r" (x)                \
 268         : "r" (addr)                            \
 269         : "t");                                 \
 270 })
 271
 272 #define __get_user_4(x,addr,err) ({             \
 273 __asm__("stc    r7_bank, %1\n\t"                \
 274         "mov.l  @(8,%1), %1\n\t"                \
 275         "and    %2, %1\n\t"                     \
 276         "cmp/pz %1\n\t"                         \
 277         "bt/s   1f\n\t"                         \
 278         " mov   #0, %0\n\t"                     \
 279         "0:\n"                                  \
 280         "mov    #-14, %0\n\t"                   \
 281         "bra    2f\n\t"                         \
 282         " mov   #0, %1\n"                       \
 283         "1:\n\t"                                \
 284         "mov.l  @%2, %1\n\t"                    \
 285         "2:\n"                                  \
 286         ".section       __ex_table,\"a\"\n\t"   \
 287         ".long  1b, 0b\n\t"                     \
 288         ".previous"                             \
 289         : "=&r" (err), "=&r" (x)                \
 290         : "r" (addr)                            \
 291         : "t");                                 \
 292 })
 293
 294 #define __get_user_asm(x, addr, err, insn) \
 295 ({ \
 296 __asm__ __volatile__( \
 297         "1:\n\t" \
 298         "mov." insn "   %2, %1\n\t" \
 299         "mov    #0, %0\n" \
 300         "2:\n" \
 301         ".section       .fixup,\"ax\"\n" \
 302         "3:\n\t" \
 303         "mov    #0, %1\n\t" \
 304         "mov.l  4f, %0\n\t" \
 305         "jmp    @%0\n\t" \
 306         " mov   %3, %0\n" \
 307         "4:     .long   2b\n\t" \
 308         ".previous\n" \
 309         ".section       __ex_table,\"a\"\n\t" \
 310         ".long  1b, 3b\n\t" \
 311         ".previous" \
 312         :"=&r" (err), "=&r" (x) \
 313         :"m" (__m(addr)), "i" (-EFAULT)); })
 314
 315 extern void __get_user_unknown(void);
 316
 317 #define __put_user_size(x,ptr,size,retval)              \
 318 do {                                                    \
 319         retval = 0;                                     \
 320         switch (size) {                                 \
 321         case 1:                                         \
 322                 __put_user_asm(x, ptr, retval, "b");    \
 323                 break;                                  \
 324         case 2:                                         \
 325                 __put_user_asm(x, ptr, retval, "w");    \
 326                 break;                                  \
 327         case 4:                                         \
 328                 __put_user_asm(x, ptr, retval, "l");    \
 329                 break;                                  \
 330         case 8:                                         \
 331                 __put_user_u64(x, ptr, retval);         \
 332                 break;                                  \
 333         default:                                        \
 334                 __put_user_unknown();                   \
 335         }                                               \
 336 } while (0)
 337
 338 #define __put_user_nocheck(x,ptr,size)                  \
 339 ({                                                      \
 340         long __pu_err;                                  \
 341         __put_user_size((x),(ptr),(size),__pu_err);     \
 342         __pu_err;                                       \
 343 })
 344
 345 #define __put_user_check(x,ptr,size)                            \
 346 ({                                                              \
 347         long __pu_err = -EFAULT;                                \
 348         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 349                                                                 \
 350         if (__access_ok((unsigned long)__pu_addr,size))         \
 351                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 352         __pu_err;                                               \
 353 })
 354
 355 #define __put_user_asm(x, addr, err, insn) \
 356 ({ \
 357 __asm__ __volatile__( \
 358         "1:\n\t" \
 359         "mov." insn "   %1, %2\n\t" \
 360         "mov    #0, %0\n" \
 361         "2:\n" \
 362         ".section       .fixup,\"ax\"\n" \
 363         "3:\n\t" \
 364         "nop\n\t" \
 365         "mov.l  4f, %0\n\t" \
 366         "jmp    @%0\n\t" \
 367         "mov    %3, %0\n" \
 368         "4:     .long   2b\n\t" \
 369         ".previous\n" \
 370         ".section       __ex_table,\"a\"\n\t" \
 371         ".long  1b, 3b\n\t" \
 372         ".previous" \
 373         :"=&r" (err) \
 374         :"r" (x), "m" (__m(addr)), "i" (-EFAULT) \
 375         :"memory"); })
 376
 377 #if defined(__LITTLE_ENDIAN__)
 378 #define __put_user_u64(val,addr,retval) \
 379 ({ \
 380 __asm__ __volatile__( \
 381         "1:\n\t" \
 382         "mov.l  %R1,%2\n\t" \
 383         "mov.l  %S1,%T2\n\t" \
 384         "mov    #0,%0\n" \
 385         "2:\n" \
 386         ".section       .fixup,\"ax\"\n" \
 387         "3:\n\t" \
 388         "nop\n\t" \
 389         "mov.l  4f,%0\n\t" \
 390         "jmp    @%0\n\t" \
 391         " mov   %3,%0\n" \
 392         "4:     .long   2b\n\t" \
 393         ".previous\n" \
 394         ".section       __ex_table,\"a\"\n\t" \
 395         ".long  1b, 3b\n\t" \
 396         ".previous" \
 397         : "=r" (retval) \
 398         : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \
 399         : "memory"); })
 400 #else
 401 #define __put_user_u64(val,addr,retval) \
 402 ({ \
 403 __asm__ __volatile__( \
 404         "1:\n\t" \
 405         "mov.l  %S1,%2\n\t" \
 406         "mov.l  %R1,%T2\n\t" \
 407         "mov    #0,%0\n" \
 408         "2:\n" \
 409         ".section       .fixup,\"ax\"\n" \
 410         "3:\n\t" \
 411         "nop\n\t" \
 412         "mov.l  4f,%0\n\t" \
 413         "jmp    @%0\n\t" \
 414         " mov   %3,%0\n" \
 415         "4:     .long   2b\n\t" \
 416         ".previous\n" \
 417         ".section       __ex_table,\"a\"\n\t" \
 418         ".long  1b, 3b\n\t" \
 419         ".previous" \
 420         : "=r" (retval) \
 421         : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \
 422         : "memory"); })
 423 #endif
 424
 425 extern void __put_user_unknown(void);
 426 \f
 427 /* Generic arbitrary sized copy.  */
 428 /* Return the number of bytes NOT copied */
 429 extern __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
 430
 431 #define copy_to_user(to,from,n) ({ \
 432 void *__copy_to = (void *) (to); \
 433 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 434 __kernel_size_t __copy_res; \
 435 if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \
 436 __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \
 437 } else __copy_res = __copy_size; \
 438 __copy_res; })
 439
 440 #define __copy_to_user(to,from,n)               \
 441         __copy_user((void *)(to),               \
 442                     (void *)(from), n)
 443
 444 #define __copy_to_user_inatomic __copy_to_user
 445 #define __copy_from_user_inatomic __copy_from_user
 446
 447
 448 #define copy_from_user(to,from,n) ({ \
 449 void *__copy_to = (void *) (to); \
 450 void *__copy_from = (void *) (from); \
 451 __kernel_size_t __copy_size = (__kernel_size_t) (n); \
 452 __kernel_size_t __copy_res; \
 453 if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \
 454 __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \
 455 } else __copy_res = __copy_size; \
 456 __copy_res; })
 457
 458 #define __copy_from_user(to,from,n)             \
 459         __copy_user((void *)(to),               \
 460                     (void *)(from), n)
 461
 462 /*
 463  * Clear the area and return remaining number of bytes
 464  * (on failure.  Usually it's 0.)
 465  */
 466 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
 467
 468 #define clear_user(addr,n) ({ \
 469 void * __cl_addr = (addr); \
 470 unsigned long __cl_size = (n); \
 471 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
 472 __cl_size = __clear_user(__cl_addr, __cl_size); \
 473 __cl_size; })
 474
 475 static __inline__ int
 476 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
 477 {
 478         __kernel_size_t res;
 479         unsigned long __dummy, _d, _s;
 480
 481         __asm__ __volatile__(
 482                 "9:\n"
 483                 "mov.b  @%2+, %1\n\t"
 484                 "cmp/eq #0, %1\n\t"
 485                 "bt/s   2f\n"
 486                 "1:\n"
 487                 "mov.b  %1, @%3\n\t"
 488                 "dt     %7\n\t"
 489                 "bf/s   9b\n\t"
 490                 " add   #1, %3\n\t"
 491                 "2:\n\t"
 492                 "sub    %7, %0\n"
 493                 "3:\n"
 494                 ".section .fixup,\"ax\"\n"
 495                 "4:\n\t"
 496                 "mov.l  5f, %1\n\t"
 497                 "jmp    @%1\n\t"
 498                 " mov   %8, %0\n\t"
 499                 ".balign 4\n"
 500                 "5:     .long 3b\n"
 501                 ".previous\n"
 502                 ".section __ex_table,\"a\"\n"
 503                 "       .balign 4\n"
 504                 "       .long 9b,4b\n"
 505                 ".previous"
 506                 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d)
 507                 : "0" (__count), "2" (__src), "3" (__dest), "r" (__count),
 508                   "i" (-EFAULT)
 509                 : "memory", "t");
 510
 511         return res;
 512 }
 513
 514 #define strncpy_from_user(dest,src,count) ({ \
 515 unsigned long __sfu_src = (unsigned long) (src); \
 516 int __sfu_count = (int) (count); \
 517 long __sfu_res = -EFAULT; \
 518 if(__access_ok(__sfu_src, __sfu_count)) { \
 519 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
 520 } __sfu_res; })
 521
 522 /*
 523  * Return the size of a string (including the ending 0!)
 524  */
 525 static __inline__ long __strnlen_user(const char __user *__s, long __n)
 526 {
 527         unsigned long res;
 528         unsigned long __dummy;
 529
 530         __asm__ __volatile__(
 531                 "9:\n"
 532                 "cmp/eq %4, %0\n\t"
 533                 "bt     2f\n"
 534                 "1:\t"
 535                 "mov.b  @(%0,%3), %1\n\t"
 536                 "tst    %1, %1\n\t"
 537                 "bf/s   9b\n\t"
 538                 " add   #1, %0\n"
 539                 "2:\n"
 540                 ".section .fixup,\"ax\"\n"
 541                 "3:\n\t"
 542                 "mov.l  4f, %1\n\t"
 543                 "jmp    @%1\n\t"
 544                 " mov   %5, %0\n"
 545                 ".balign 4\n"
 546                 "4:     .long 2b\n"
 547                 ".previous\n"
 548                 ".section __ex_table,\"a\"\n"
 549                 "       .balign 4\n"
 550                 "       .long 1b,3b\n"
 551                 ".previous"
 552                 : "=z" (res), "=&r" (__dummy)
 553                 : "0" (0), "r" (__s), "r" (__n), "i" (-EFAULT)
 554                 : "t");
 555         return res;
 556 }
 557
 558 static __inline__ long strnlen_user(const char __user *s, long n)
 559 {
 560         if (!access_ok(VERIFY_READ, s, n))
 561                 return 0;
 562         else
 563                 return __strnlen_user(s, n);
 564 }
 565
 566 static __inline__ long strlen_user(const char __user *s)
 567 {
 568         if (!access_ok(VERIFY_READ, s, 0))
 569                 return 0;
 570         else
 571                 return __strnlen_user(s, ~0UL >> 1);
 572 }
 573
 574 /*
 575  * The exception table consists of pairs of addresses: the first is the
 576  * address of an instruction that is allowed to fault, and the second is
 577  * the address at which the program should continue.  No registers are
 578  * modified, so it is entirely up to the continuation code to figure out
 579  * what to do.
 580  *
 581  * All the routines below use bits of fixup code that are out of line
 582  * with the main instruction path.  This means when everything is well,
 583  * we don't even have to jump over them.  Further, they do not intrude
 584  * on our cache or tlb entries.
 585  */
 586
 587 struct exception_table_entry
 588 {
 589         unsigned long insn, fixup;
 590 };
 591
 592 extern int fixup_exception(struct pt_regs *regs);
 593
 594 #endif /* __ASM_SH_UACCESS_H */