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  * 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 #endif /* CONFIG_MMU */
  97
  98 #define access_ok(type, addr, size)     \
  99         (__chk_user_ptr(addr),          \
 100          __access_ok((unsigned long __force)(addr), (size)))
 101
 102 /*
 103  * Uh, these should become the main single-value transfer routines ...
 104  * They automatically use the right size if we just have the right
 105  * pointer type ...
 106  *
 107  * As SuperH uses the same address space for kernel and user data, we
 108  * can just do these as direct assignments.
 109  *
 110  * Careful to not
 111  * (a) re-use the arguments for side effects (sizeof is ok)
 112  * (b) require any knowledge of processes at this stage
 113  */
 114 #define put_user(x,ptr)         __put_user_check((x), (ptr), sizeof(*(ptr)))
 115 #define get_user(x,ptr)         __get_user_check((x), (ptr), sizeof(*(ptr)))
 116
 117 /*
 118  * The "__xxx" versions do not do address space checking, useful when
 119  * doing multiple accesses to the same area (the user has to do the
 120  * checks by hand with "access_ok()")
 121  */
 122 #define __put_user(x,ptr)       __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 123 #define __get_user(x,ptr)       __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 124
 125 struct __large_struct { unsigned long buf[100]; };
 126 #define __m(x) (*(struct __large_struct __user *)(x))
 127
 128 #define __get_user_size(x,ptr,size,retval)                      \
 129 do {                                                            \
 130         retval = 0;                                             \
 131         switch (size) {                                         \
 132         case 1:                                                 \
 133                 __get_user_asm(x, ptr, retval, "b");            \
 134                 break;                                          \
 135         case 2:                                                 \
 136                 __get_user_asm(x, ptr, retval, "w");            \
 137                 break;                                          \
 138         case 4:                                                 \
 139                 __get_user_asm(x, ptr, retval, "l");            \
 140                 break;                                          \
 141         default:                                                \
 142                 __get_user_unknown();                           \
 143                 break;                                          \
 144         }                                                       \
 145 } while (0)
 146
 147 #define __get_user_nocheck(x,ptr,size)                          \
 148 ({                                                              \
 149         long __gu_err;                                          \
 150         unsigned long __gu_val;                                 \
 151         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 152         __chk_user_ptr(ptr);                                    \
 153         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 154         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 155         __gu_err;                                               \
 156 })
 157
 158 #define __get_user_check(x,ptr,size)                                    \
 159 ({                                                                      \
 160         long __gu_err = -EFAULT;                                        \
 161         unsigned long __gu_val = 0;                                     \
 162         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 163         if (likely(access_ok(VERIFY_READ, __gu_addr, (size))))          \
 164                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 165         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 166         __gu_err;                                                       \
 167 })
 168
 169 #define __get_user_asm(x, addr, err, insn) \
 170 ({ \
 171 __asm__ __volatile__( \
 172         "1:\n\t" \
 173         "mov." insn "   %2, %1\n\t" \
 174         "2:\n" \
 175         ".section       .fixup,\"ax\"\n" \
 176         "3:\n\t" \
 177         "mov    #0, %1\n\t" \
 178         "mov.l  4f, %0\n\t" \
 179         "jmp    @%0\n\t" \
 180         " mov   %3, %0\n\t" \
 181         ".balign        4\n" \
 182         "4:     .long   2b\n\t" \
 183         ".previous\n" \
 184         ".section       __ex_table,\"a\"\n\t" \
 185         ".long  1b, 3b\n\t" \
 186         ".previous" \
 187         :"=&r" (err), "=&r" (x) \
 188         :"m" (__m(addr)), "i" (-EFAULT), "0" (err)); })
 189
 190 extern void __get_user_unknown(void);
 191
 192 #define __put_user_size(x,ptr,size,retval)              \
 193 do {                                                    \
 194         retval = 0;                                     \
 195         switch (size) {                                 \
 196         case 1:                                         \
 197                 __put_user_asm(x, ptr, retval, "b");    \
 198                 break;                                  \
 199         case 2:                                         \
 200                 __put_user_asm(x, ptr, retval, "w");    \
 201                 break;                                  \
 202         case 4:                                         \
 203                 __put_user_asm(x, ptr, retval, "l");    \
 204                 break;                                  \
 205         case 8:                                         \
 206                 __put_user_u64(x, ptr, retval);         \
 207                 break;                                  \
 208         default:                                        \
 209                 __put_user_unknown();                   \
 210         }                                               \
 211 } while (0)
 212
 213 #define __put_user_nocheck(x,ptr,size)                          \
 214 ({                                                              \
 215         long __pu_err;                                          \
 216         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 217         __chk_user_ptr(ptr);                                    \
 218         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 219         __pu_err;                                               \
 220 })
 221
 222 #define __put_user_check(x,ptr,size)                            \
 223 ({                                                              \
 224         long __pu_err = -EFAULT;                                \
 225         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 226         if (likely(access_ok(VERIFY_WRITE, __pu_addr, size)))   \
 227                 __put_user_size((x), __pu_addr, (size),         \
 228                                 __pu_err);                      \
 229         __pu_err;                                               \
 230 })
 231
 232 #define __put_user_asm(x, addr, err, insn) \
 233 ({ \
 234 __asm__ __volatile__( \
 235         "1:\n\t" \
 236         "mov." insn "   %1, %2\n\t" \
 237         "2:\n" \
 238         ".section       .fixup,\"ax\"\n" \
 239         "3:\n\t" \
 240         "mov.l  4f, %0\n\t" \
 241         "jmp    @%0\n\t" \
 242         " mov   %3, %0\n\t" \
 243         ".balign        4\n" \
 244         "4:     .long   2b\n\t" \
 245         ".previous\n" \
 246         ".section       __ex_table,\"a\"\n\t" \
 247         ".long  1b, 3b\n\t" \
 248         ".previous" \
 249         :"=&r" (err) \
 250         :"r" (x), "m" (__m(addr)), "i" (-EFAULT), "0" (err)     \
 251         :"memory"); })
 252
 253 #if defined(CONFIG_CPU_LITTLE_ENDIAN)
 254 #define __put_user_u64(val,addr,retval) \
 255 ({ \
 256 __asm__ __volatile__( \
 257         "1:\n\t" \
 258         "mov.l  %R1,%2\n\t" \
 259         "mov.l  %S1,%T2\n\t" \
 260         "2:\n" \
 261         ".section       .fixup,\"ax\"\n" \
 262         "3:\n\t" \
 263         "mov.l  4f,%0\n\t" \
 264         "jmp    @%0\n\t" \
 265         " mov   %3,%0\n\t" \
 266         ".balign        4\n" \
 267         "4:     .long   2b\n\t" \
 268         ".previous\n" \
 269         ".section       __ex_table,\"a\"\n\t" \
 270         ".long  1b, 3b\n\t" \
 271         ".previous" \
 272         : "=r" (retval) \
 273         : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
 274         : "memory"); })
 275 #else
 276 #define __put_user_u64(val,addr,retval) \
 277 ({ \
 278 __asm__ __volatile__( \
 279         "1:\n\t" \
 280         "mov.l  %S1,%2\n\t" \
 281         "mov.l  %R1,%T2\n\t" \
 282         "2:\n" \
 283         ".section       .fixup,\"ax\"\n" \
 284         "3:\n\t" \
 285         "mov.l  4f,%0\n\t" \
 286         "jmp    @%0\n\t" \
 287         " mov   %3,%0\n\t" \
 288         ".balign        4\n" \
 289         "4:     .long   2b\n\t" \
 290         ".previous\n" \
 291         ".section       __ex_table,\"a\"\n\t" \
 292         ".long  1b, 3b\n\t" \
 293         ".previous" \
 294         : "=r" (retval) \
 295         : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
 296         : "memory"); })
 297 #endif
 298
 299 extern void __put_user_unknown(void);
 300
 301 /* Generic arbitrary sized copy.  */
 302 /* Return the number of bytes NOT copied */
 303 __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
 304
 305
 306 static __always_inline unsigned long
 307 __copy_from_user(void *to, const void __user *from, unsigned long n)
 308 {
 309         return __copy_user(to, (__force void *)from, n);
 310 }
 311
 312 static __always_inline unsigned long __must_check
 313 __copy_to_user(void __user *to, const void *from, unsigned long n)
 314 {
 315         return __copy_user((__force void *)to, from, n);
 316 }
 317
 318 #define __copy_to_user_inatomic __copy_to_user
 319 #define __copy_from_user_inatomic __copy_from_user
 320
 321 /*
 322  * Clear the area and return remaining number of bytes
 323  * (on failure.  Usually it's 0.)
 324  */
 325 extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size);
 326
 327 #define clear_user(addr,n) ({ \
 328 void * __cl_addr = (addr); \
 329 unsigned long __cl_size = (n); \
 330 if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \
 331 __cl_size = __clear_user(__cl_addr, __cl_size); \
 332 __cl_size; })
 333
 334 static __inline__ int
 335 __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count)
 336 {
 337         __kernel_size_t res;
 338         unsigned long __dummy, _d, _s, _c;
 339
 340         __asm__ __volatile__(
 341                 "9:\n"
 342                 "mov.b  @%2+, %1\n\t"
 343                 "cmp/eq #0, %1\n\t"
 344                 "bt/s   2f\n"
 345                 "1:\n"
 346                 "mov.b  %1, @%3\n\t"
 347                 "dt     %4\n\t"
 348                 "bf/s   9b\n\t"
 349                 " add   #1, %3\n\t"
 350                 "2:\n\t"
 351                 "sub    %4, %0\n"
 352                 "3:\n"
 353                 ".section .fixup,\"ax\"\n"
 354                 "4:\n\t"
 355                 "mov.l  5f, %1\n\t"
 356                 "jmp    @%1\n\t"
 357                 " mov   %9, %0\n\t"
 358                 ".balign 4\n"
 359                 "5:     .long 3b\n"
 360                 ".previous\n"
 361                 ".section __ex_table,\"a\"\n"
 362                 "       .balign 4\n"
 363                 "       .long 9b,4b\n"
 364                 ".previous"
 365                 : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d), "=r"(_c)
 366                 : "0" (__count), "2" (__src), "3" (__dest), "4" (__count),
 367                   "i" (-EFAULT)
 368                 : "memory", "t");
 369
 370         return res;
 371 }
 372
 373 /**
 374  * strncpy_from_user: - Copy a NUL terminated string from userspace.
 375  * @dst:   Destination address, in kernel space.  This buffer must be at
 376  *         least @count bytes long.
 377  * @src:   Source address, in user space.
 378  * @count: Maximum number of bytes to copy, including the trailing NUL.
 379  *
 380  * Copies a NUL-terminated string from userspace to kernel space.
 381  *
 382  * On success, returns the length of the string (not including the trailing
 383  * NUL).
 384  *
 385  * If access to userspace fails, returns -EFAULT (some data may have been
 386  * copied).
 387  *
 388  * If @count is smaller than the length of the string, copies @count bytes
 389  * and returns @count.
 390  */
 391 #define strncpy_from_user(dest,src,count) ({ \
 392 unsigned long __sfu_src = (unsigned long) (src); \
 393 int __sfu_count = (int) (count); \
 394 long __sfu_res = -EFAULT; \
 395 if(__access_ok(__sfu_src, __sfu_count)) { \
 396 __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \
 397 } __sfu_res; })
 398
 399 /*
 400  * Return the size of a string (including the ending 0 even when we have
 401  * exceeded the maximum string length).
 402  */
 403 static __inline__ long __strnlen_user(const char __user *__s, long __n)
 404 {
 405         unsigned long res;
 406         unsigned long __dummy;
 407
 408         __asm__ __volatile__(
 409                 "1:\t"
 410                 "mov.b  @(%0,%3), %1\n\t"
 411                 "cmp/eq %4, %0\n\t"
 412                 "bt/s   2f\n\t"
 413                 " add   #1, %0\n\t"
 414                 "tst    %1, %1\n\t"
 415                 "bf     1b\n\t"
 416                 "2:\n"
 417                 ".section .fixup,\"ax\"\n"
 418                 "3:\n\t"
 419                 "mov.l  4f, %1\n\t"
 420                 "jmp    @%1\n\t"
 421                 " mov   #0, %0\n"
 422                 ".balign 4\n"
 423                 "4:     .long 2b\n"
 424                 ".previous\n"
 425                 ".section __ex_table,\"a\"\n"
 426                 "       .balign 4\n"
 427                 "       .long 1b,3b\n"
 428                 ".previous"
 429                 : "=z" (res), "=&r" (__dummy)
 430                 : "0" (0), "r" (__s), "r" (__n)
 431                 : "t");
 432         return res;
 433 }
 434
 435 /**
 436  * strnlen_user: - Get the size of a string in user space.
 437  * @s: The string to measure.
 438  * @n: The maximum valid length
 439  *
 440  * Context: User context only.  This function may sleep.
 441  *
 442  * Get the size of a NUL-terminated string in user space.
 443  *
 444  * Returns the size of the string INCLUDING the terminating NUL.
 445  * On exception, returns 0.
 446  * If the string is too long, returns a value greater than @n.
 447  */
 448 static __inline__ long strnlen_user(const char __user *s, long n)
 449 {
 450         if (!__addr_ok(s))
 451                 return 0;
 452         else
 453                 return __strnlen_user(s, n);
 454 }
 455
 456 /**
 457  * strlen_user: - Get the size of a string in user space.
 458  * @str: The string to measure.
 459  *
 460  * Context: User context only.  This function may sleep.
 461  *
 462  * Get the size of a NUL-terminated string in user space.
 463  *
 464  * Returns the size of the string INCLUDING the terminating NUL.
 465  * On exception, returns 0.
 466  *
 467  * If there is a limit on the length of a valid string, you may wish to
 468  * consider using strnlen_user() instead.
 469  */
 470 #define strlen_user(str)        strnlen_user(str, ~0UL >> 1)
 471
 472 /*
 473  * The exception table consists of pairs of addresses: the first is the
 474  * address of an instruction that is allowed to fault, and the second is
 475  * the address at which the program should continue.  No registers are
 476  * modified, so it is entirely up to the continuation code to figure out
 477  * what to do.
 478  *
 479  * All the routines below use bits of fixup code that are out of line
 480  * with the main instruction path.  This means when everything is well,
 481  * we don't even have to jump over them.  Further, they do not intrude
 482  * on our cache or tlb entries.
 483  */
 484
 485 struct exception_table_entry
 486 {
 487         unsigned long insn, fixup;
 488 };
 489
 490 extern int fixup_exception(struct pt_regs *regs);
 491
 492 #endif /* __ASM_SH_UACCESS_32_H */