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