include/asm-sh/uaccess_32.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_32_H
  14 #define __ASM_SH_UACCESS_32_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 static inline int __access_ok(unsigned long addr, unsigned long size)
  60 {
  61         return 1;
  62 }
  63 #else /* CONFIG_MMU */
  64 #define __addr_ok(addr) \
  65         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
  66
  67 #define get_fs()        (current_thread_info()->addr_limit)
  68 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  69
  70 /*
  71  * __access_ok: Check if address with size is OK or not.
  72  *
  73  * Uhhuh, this needs 33-bit arithmetic. We have a carry..
  74  *
  75  * sum := addr + size;  carry? --> flag = true;
  76  * if (sum >= addr_limit) flag = true;
  77  */
  78 static inline int __access_ok(unsigned long addr, unsigned long size)
  79 {
  80         unsigned long flag, sum;
  81
  82         __asm__("clrt\n\t"
  83                 "addc   %3, %1\n\t"
  84                 "movt   %0\n\t"
  85                 "cmp/hi %4, %1\n\t"
  86                 "rotcl  %0"
  87                 :"=&r" (flag), "=r" (sum)
  88                 :"1" (addr), "r" (size),
  89                  "r" (current_thread_info()->addr_limit.seg)
  90                 :"t");
  91         return flag == 0;
  92 }
  93 #endif /* CONFIG_MMU */
  94
  95 #define access_ok(type, addr, size)     \
  96         (__chk_user_ptr(addr),          \
  97          __access_ok((unsigned long __force)(addr), (size)))
  98
  99 /*
 100  * Uh, these should become the main single-value transfer routines ...
 101  * They automatically use the right size if we just have the right
 102  * pointer type ...
 103  *
 104  * As SuperH uses the same address space for kernel and user data, we
 105  * can just do these as direct assignments.
 106  *
 107  * Careful to not
 108  * (a) re-use the arguments for side effects (sizeof is ok)
 109  * (b) require any knowledge of processes at this stage
 110  */
 111 #define put_user(x,ptr)         __put_user_check((x), (ptr), sizeof(*(ptr)))
 112 #define get_user(x,ptr)         __get_user_check((x), (ptr), sizeof(*(ptr)))
 113
 114 /*
 115  * The "__xxx" versions do not do address space checking, useful when
 116  * doing multiple accesses to the same area (the user has to do the
 117  * checks by hand with "access_ok()")
 118  */
 119 #define __put_user(x,ptr)       __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 120 #define __get_user(x,ptr)       __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 121
 122 struct __large_struct { unsigned long buf[100]; };
 123 #define __m(x) (*(struct __large_struct __user *)(x))
 124
 125 #define __get_user_size(x,ptr,size,retval)                      \
 126 do {                                                            \
 127         retval = 0;                                             \
 128         switch (size) {                                         \
 129         case 1:                                                 \
 130                 __get_user_asm(x, ptr, retval, "b");            \
 131                 break;                                          \
 132         case 2:                                                 \
 133                 __get_user_asm(x, ptr, retval, "w");            \
 134                 break;                                          \
 135         case 4:                                                 \
 136                 __get_user_asm(x, ptr, retval, "l");            \
 137                 break;                                          \
 138         default:                                                \
 139                 __get_user_unknown();                           \
 140                 break;                                          \
 141         }                                                       \
 142 } while (0)
 143
 144 #define __get_user_nocheck(x,ptr,size)                          \
 145 ({                                                              \
 146         long __gu_err;                                          \
 147         unsigned long __gu_val;                                 \
 148         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 149         __chk_user_ptr(ptr);                                    \
 150         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 151         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 152         __gu_err;                                               \
 153 })
 154
 155 #define __get_user_check(x,ptr,size)                                    \
 156 ({                                                                      \
 157         long __gu_err = -EFAULT;                                        \
 158         unsigned long __gu_val = 0;                                     \
 159         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 160         if (likely(access_ok(VERIFY_READ, __gu_addr, (size))))          \
 161                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 162         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 163         __gu_err;                                                       \
 164 })
 165
 166 #define __get_user_asm(x, addr, err, insn) \
 167 ({ \
 168 __asm__ __volatile__( \
 169         "1:\n\t" \
 170         "mov." insn "   %2, %1\n\t" \
 171         "2:\n" \
 172         ".section       .fixup,\"ax\"\n" \
 173         "3:\n\t" \
 174         "mov    #0, %1\n\t" \
 175         "mov.l  4f, %0\n\t" \
 176         "jmp    @%0\n\t" \
 177         " mov   %3, %0\n\t" \
 178         ".balign        4\n" \
 179         "4:     .long   2b\n\t" \
 180         ".previous\n" \
 181         ".section       __ex_table,\"a\"\n\t" \
 182         ".long  1b, 3b\n\t" \
 183         ".previous" \
 184         :"=&r" (err), "=&r" (x) \
 185         :"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
 186
 187 extern void __get_user_unknown(void);
 188
 189 #define __put_user_size(x,ptr,size,retval)              \
 190 do {                                                    \
 191         retval = 0;                                     \
 192         switch (size) {                                 \
 193         case 1:                                         \
 194                 __put_user_asm(x, ptr, retval, "b");    \
 195                 break;                                  \
 196         case 2:                                         \
 197                 __put_user_asm(x, ptr, retval, "w");    \
 198                 break;                                  \
 199         case 4:                                         \
 200                 __put_user_asm(x, ptr, retval, "l");    \
 201                 break;                                  \
 202         case 8:                                         \
 203                 __put_user_u64(x, ptr, retval);         \
 204                 break;                                  \
 205         default:                                        \
 206                 __put_user_unknown();                   \
 207         }                                               \
 208 } while (0)
 209
 210 #define __put_user_nocheck(x,ptr,size)                          \
 211 ({                                                              \
 212         long __pu_err;                                          \
 213         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 214         __chk_user_ptr(ptr);                                    \
 215         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 216         __pu_err;                                               \
 217 })
 218
 219 #define __put_user_check(x,ptr,size)                            \
 220 ({                                                              \
 221         long __pu_err = -EFAULT;                                \
 222         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 223         if (likely(access_ok(VERIFY_WRITE, __pu_addr, size)))   \
 224                 __put_user_size((x), __pu_addr, (size),         \
 225                                 __pu_err);                      \
 226         __pu_err;                                               \
 227 })
 228
 229 #define __put_user_asm(x, addr, err, insn) \
 230 ({ \
 231 __asm__ __volatile__( \
 232         "1:\n\t" \
 233         "mov." insn "   %1, %2\n\t" \
 234         "2:\n" \
 235         ".section       .fixup,\"ax\"\n" \
 236         "3:\n\t" \
 237         "mov.l  4f, %0\n\t" \
 238         "jmp    @%0\n\t" \
 239         " mov   %3, %0\n\t" \
 240         ".balign        4\n" \
 241         "4:     .long   2b\n\t" \
 242         ".previous\n" \
 243         ".section       __ex_table,\"a\"\n\t" \
 244         ".long  1b, 3b\n\t" \
 245         ".previous" \
 246         :"=&r" (err) \
 247         :"r" (x), "m" (__m(addr)), "i" (-EFAULT), "0" (err)     \
 248         :"memory"); })
 249
 250 #if defined(CONFIG_CPU_LITTLE_ENDIAN)
 251 #define __put_user_u64(val,addr,retval) \
 252 ({ \
 253 __asm__ __volatile__( \
 254         "1:\n\t" \
 255         "mov.l  %R1,%2\n\t" \
 256         "mov.l  %S1,%T2\n\t" \
 257         "2:\n" \
 258         ".section       .fixup,\"ax\"\n" \
 259         "3:\n\t" \
 260         "mov.l  4f,%0\n\t" \
 261         "jmp    @%0\n\t" \
 262         " mov   %3,%0\n\t" \
 263         ".balign        4\n" \
 264         "4:     .long   2b\n\t" \
 265         ".previous\n" \
 266         ".section       __ex_table,\"a\"\n\t" \
 267         ".long  1b, 3b\n\t" \
 268         ".previous" \
 269         : "=r" (retval) \
 270         : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
 271         : "memory"); })
 272 #else
 273 #define __put_user_u64(val,addr,retval) \
 274 ({ \
 275 __asm__ __volatile__( \
 276         "1:\n\t" \
 277         "mov.l  %S1,%2\n\t" \
 278         "mov.l  %R1,%T2\n\t" \
 279         "2:\n" \
 280         ".section       .fixup,\"ax\"\n" \
 281         "3:\n\t" \
 282         "mov.l  4f,%0\n\t" \
 283         "jmp    @%0\n\t" \
 284         " mov   %3,%0\n\t" \
 285         ".balign        4\n" \
 286         "4:     .long   2b\n\t" \
 287         ".previous\n" \
 288         ".section       __ex_table,\"a\"\n\t" \
 289         ".long  1b, 3b\n\t" \
 290         ".previous" \
 291         : "=r" (retval) \
 292         : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
 293         : "memory"); })
 294 #endif
 295
 296 extern void __put_user_unknown(void);
 297
 298 /* Generic arbitrary sized copy.  */
 299 /* Return the number of bytes NOT copied */
 300 __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
 301
 302
 303 static __always_inline unsigned long
 304 __copy_from_user(void *to, const void __user *from, unsigned long n)
 305 {
 306         return __copy_user(to, (__force void *)from, n);
 307 }
 308
 309 static __always_inline unsigned long __must_check
 310 __copy_to_user(void __user *to, const void *from, unsigned long n)
 311 {
 312         return __copy_user((__force void *)to, from, n);
 313 }
 314
 315 #define __copy_to_user_inatomic __copy_to_user
 316 #define __copy_from_user_inatomic __copy_from_user
 317
 318 /*
 319  * Clear the area and return remaining number of bytes
 320  * (on failure.  Usually it's 0.)
 321  */
 322 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
 323
 324 #define clear_user(addr,n) ({ \
 325 void * __cl_addr = (addr); \
 326 unsigned long __cl_size = (n); \
 327 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
 328 __cl_size = __clear_user(__cl_addr, __cl_size); \
 329 __cl_size; })
 330
 331 static __inline__ int
 332 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
 333 {
 334         __kernel_size_t res;
 335         unsigned long __dummy, _d, _s, _c;
 336
 337         __asm__ __volatile__(
 338                 "9:\n"
 339                 "mov.b  @%2+, %1\n\t"
 340                 "cmp/eq #0, %1\n\t"
 341                 "bt/s   2f\n"
 342                 "1:\n"
 343                 "mov.b  %1, @%3\n\t"
 344                 "dt     %4\n\t"
 345                 "bf/s   9b\n\t"
 346                 " add   #1, %3\n\t"
 347                 "2:\n\t"
 348                 "sub    %4, %0\n"
 349                 "3:\n"
 350                 ".section .fixup,\"ax\"\n"
 351                 "4:\n\t"
 352                 "mov.l  5f, %1\n\t"
 353                 "jmp    @%1\n\t"
 354                 " mov   %9, %0\n\t"
 355                 ".balign 4\n"
 356                 "5:     .long 3b\n"
 357                 ".previous\n"
 358                 ".section __ex_table,\"a\"\n"
 359                 "       .balign 4\n"
 360                 "       .long 9b,4b\n"
 361                 ".previous"
 362                 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d), "=r"(_c)
 363                 : "0" (__count), "2" (__src), "3" (__dest), "4" (__count),
 364                   "i" (-EFAULT)
 365                 : "memory", "t");
 366
 367         return res;
 368 }
 369
 370 /**
 371  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 372  * @dst:   Destination address, in kernel space.  This buffer must be at
 373  *         least @count bytes long.
 374  * @src:   Source address, in user space.
 375  * @count: Maximum number of bytes to copy, including the trailing NUL.
 376  *
 377  * Copies a NUL-terminated string from userspace to kernel space.
 378  *
 379  * On success, returns the length of the string (not including the trailing
 380  * NUL).
 381  *
 382  * If access to userspace fails, returns -EFAULT (some data may have been
 383  * copied).
 384  *
 385  * If @count is smaller than the length of the string, copies @count bytes
 386  * and returns @count.
 387  */
 388 #define strncpy_from_user(dest,src,count) ({ \
 389 unsigned long __sfu_src = (unsigned long) (src); \
 390 int __sfu_count = (int) (count); \
 391 long __sfu_res = -EFAULT; \
 392 if(__access_ok(__sfu_src, __sfu_count)) { \
 393 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
 394 } __sfu_res; })
 395
 396 /*
 397  * Return the size of a string (including the ending 0 even when we have
 398  * exceeded the maximum string length).
 399  */
 400 static __inline__ long __strnlen_user(const char __user *__s, long __n)
 401 {
 402         unsigned long res;
 403         unsigned long __dummy;
 404
 405         __asm__ __volatile__(
 406                 "1:\t"
 407                 "mov.b  @(%0,%3), %1\n\t"
 408                 "cmp/eq %4, %0\n\t"
 409                 "bt/s   2f\n\t"
 410                 " add   #1, %0\n\t"
 411                 "tst    %1, %1\n\t"
 412                 "bf     1b\n\t"
 413                 "2:\n"
 414                 ".section .fixup,\"ax\"\n"
 415                 "3:\n\t"
 416                 "mov.l  4f, %1\n\t"
 417                 "jmp    @%1\n\t"
 418                 " mov   #0, %0\n"
 419                 ".balign 4\n"
 420                 "4:     .long 2b\n"
 421                 ".previous\n"
 422                 ".section __ex_table,\"a\"\n"
 423                 "       .balign 4\n"
 424                 "       .long 1b,3b\n"
 425                 ".previous"
 426                 : "=z" (res), "=&r" (__dummy)
 427                 : "0" (0), "r" (__s), "r" (__n)
 428                 : "t");
 429         return res;
 430 }
 431
 432 /**
 433  * strnlen_user: - Get the size of a string in user space.
 434  * @s: The string to measure.
 435  * @n: The maximum valid length
 436  *
 437  * Context: User context only.  This function may sleep.
 438  *
 439  * Get the size of a NUL-terminated string in user space.
 440  *
 441  * Returns the size of the string INCLUDING the terminating NUL.
 442  * On exception, returns 0.
 443  * If the string is too long, returns a value greater than @n.
 444  */
 445 static __inline__ long strnlen_user(const char __user *s, long n)
 446 {
 447         if (!__addr_ok(s))
 448                 return 0;
 449         else
 450                 return __strnlen_user(s, n);
 451 }
 452
 453 /**
 454  * strlen_user: - Get the size of a string in user space.
 455  * @str: The string to measure.
 456  *
 457  * Context: User context only.  This function may sleep.
 458  *
 459  * Get the size of a NUL-terminated string in user space.
 460  *
 461  * Returns the size of the string INCLUDING the terminating NUL.
 462  * On exception, returns 0.
 463  *
 464  * If there is a limit on the length of a valid string, you may wish to
 465  * consider using strnlen_user() instead.
 466  */
 467 #define strlen_user(str)        strnlen_user(str, ~0UL >> 1)
 468
 469 /*
 470  * The exception table consists of pairs of addresses: the first is the
 471  * address of an instruction that is allowed to fault, and the second is
 472  * the address at which the program should continue.  No registers are
 473  * modified, so it is entirely up to the continuation code to figure out
 474  * what to do.
 475  *
 476  * All the routines below use bits of fixup code that are out of line
 477  * with the main instruction path.  This means when everything is well,
 478  * we don't even have to jump over them.  Further, they do not intrude
 479  * on our cache or tlb entries.
 480  */
 481
 482 struct exception_table_entry
 483 {
 484         unsigned long insn, fixup;
 485 };
 486
 487 extern int fixup_exception(struct pt_regs *regs);
 488
 489 #endif /* __ASM_SH_UACCESS_32_H */