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