arch/m32r/include/asm/uaccess.h

   1 #ifndef _ASM_M32R_UACCESS_H
   2 #define _ASM_M32R_UACCESS_H
   3
   4 /*
   5  *  linux/include/asm-m32r/uaccess.h
   6  *
   7  *  M32R version.
   8  *    Copyright (C) 2004, 2006  Hirokazu Takata <takata at linux-m32r.org>
   9  */
  10
  11 /*
  12  * User space memory access functions
  13  */
  14 #include <asm/page.h>
  15 #include <asm/setup.h>
  16 #include <linux/prefetch.h>
  17
  18 /*
  19  * The fs value determines whether argument validity checking should be
  20  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  21  * get_fs() == KERNEL_DS, checking is bypassed.
  22  *
  23  * For historical reasons, these macros are grossly misnamed.
  24  */
  25
  26 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  27
  28 #ifdef CONFIG_MMU
  29
  30 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  31 #define USER_DS         MAKE_MM_SEG(PAGE_OFFSET)
  32 #define get_ds()        (KERNEL_DS)
  33 #define get_fs()        (current_thread_info()->addr_limit)
  34 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  35
  36 #else /* not CONFIG_MMU */
  37
  38 #define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)
  39 #define USER_DS         MAKE_MM_SEG(0xFFFFFFFF)
  40 #define get_ds()        (KERNEL_DS)
  41
  42 static inline mm_segment_t get_fs(void)
  43 {
  44         return USER_DS;
  45 }
  46
  47 static inline void set_fs(mm_segment_t s)
  48 {
  49 }
  50
  51 #endif /* not CONFIG_MMU */
  52
  53 #define segment_eq(a, b)        ((a).seg == (b).seg)
  54
  55 #define __addr_ok(addr) \
  56         ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg))
  57
  58 /*
  59  * Test whether a block of memory is a valid user space address.
  60  * Returns 0 if the range is valid, nonzero otherwise.
  61  *
  62  * This is equivalent to the following test:
  63  * (u33)addr + (u33)size >= (u33)current->addr_limit.seg
  64  *
  65  * This needs 33-bit arithmetic. We have a carry...
  66  */
  67 #define __range_ok(addr, size) ({                                       \
  68         unsigned long flag, roksum;                                     \
  69         __chk_user_ptr(addr);                                           \
  70         asm (                                                           \
  71                 "       cmpu    %1, %1    ; clear cbit\n"               \
  72                 "       addx    %1, %3    ; set cbit if overflow\n"     \
  73                 "       subx    %0, %0\n"                               \
  74                 "       cmpu    %4, %1\n"                               \
  75                 "       subx    %0, %5\n"                               \
  76                 : "=&r" (flag), "=r" (roksum)                           \
  77                 : "1" (addr), "r" ((int)(size)),                        \
  78                   "r" (current_thread_info()->addr_limit.seg), "r" (0)  \
  79                 : "cbit" );                                             \
  80         flag; })
  81
  82 /**
  83  * access_ok: - Checks if a user space pointer is valid
  84  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  85  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  86  *        to write to a block, it is always safe to read from it.
  87  * @addr: User space pointer to start of block to check
  88  * @size: Size of block to check
  89  *
  90  * Context: User context only. This function may sleep if pagefaults are
  91  *          enabled.
  92  *
  93  * Checks if a pointer to a block of memory in user space is valid.
  94  *
  95  * Returns true (nonzero) if the memory block may be valid, false (zero)
  96  * if it is definitely invalid.
  97  *
  98  * Note that, depending on architecture, this function probably just
  99  * checks that the pointer is in the user space range - after calling
 100  * this function, memory access functions may still return -EFAULT.
 101  */
 102 #ifdef CONFIG_MMU
 103 #define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0))
 104 #else
 105 static inline int access_ok(int type, const void *addr, unsigned long size)
 106 {
 107         unsigned long val = (unsigned long)addr;
 108
 109         return ((val >= memory_start) && ((val + size) < memory_end));
 110 }
 111 #endif /* CONFIG_MMU */
 112
 113 #include <asm/extable.h>
 114
 115 /*
 116  * These are the main single-value transfer routines.  They automatically
 117  * use the right size if we just have the right pointer type.
 118  *
 119  * This gets kind of ugly. We want to return _two_ values in "get_user()"
 120  * and yet we don't want to do any pointers, because that is too much
 121  * of a performance impact. Thus we have a few rather ugly macros here,
 122  * and hide all the uglyness from the user.
 123  *
 124  * The "__xxx" versions of the user access functions are versions that
 125  * do not verify the address space, that must have been done previously
 126  * with a separate "access_ok()" call (this is used when we do multiple
 127  * accesses to the same area of user memory).
 128  */
 129
 130 /* Careful: we have to cast the result to the type of the pointer for sign
 131    reasons */
 132 /**
 133  * get_user: - Get a simple variable from user space.
 134  * @x:   Variable to store result.
 135  * @ptr: Source address, in user space.
 136  *
 137  * Context: User context only. This function may sleep if pagefaults are
 138  *          enabled.
 139  *
 140  * This macro copies a single simple variable from user space to kernel
 141  * space.  It supports simple types like char and int, but not larger
 142  * data types like structures or arrays.
 143  *
 144  * @ptr must have pointer-to-simple-variable type, and the result of
 145  * dereferencing @ptr must be assignable to @x without a cast.
 146  *
 147  * Returns zero on success, or -EFAULT on error.
 148  * On error, the variable @x is set to zero.
 149  */
 150 #define get_user(x, ptr)                                                        \
 151         __get_user_check((x), (ptr), sizeof(*(ptr)))
 152
 153 /**
 154  * put_user: - Write a simple value into user space.
 155  * @x:   Value to copy to user space.
 156  * @ptr: Destination address, in user space.
 157  *
 158  * Context: User context only. This function may sleep if pagefaults are
 159  *          enabled.
 160  *
 161  * This macro copies a single simple value from kernel space to user
 162  * space.  It supports simple types like char and int, but not larger
 163  * data types like structures or arrays.
 164  *
 165  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 166  * to the result of dereferencing @ptr.
 167  *
 168  * Returns zero on success, or -EFAULT on error.
 169  */
 170 #define put_user(x, ptr)                                                        \
 171         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 172
 173 /**
 174  * __get_user: - Get a simple variable from user space, with less checking.
 175  * @x:   Variable to store result.
 176  * @ptr: Source address, in user space.
 177  *
 178  * Context: User context only. This function may sleep if pagefaults are
 179  *          enabled.
 180  *
 181  * This macro copies a single simple variable from user space to kernel
 182  * space.  It supports simple types like char and int, but not larger
 183  * data types like structures or arrays.
 184  *
 185  * @ptr must have pointer-to-simple-variable type, and the result of
 186  * dereferencing @ptr must be assignable to @x without a cast.
 187  *
 188  * Caller must check the pointer with access_ok() before calling this
 189  * function.
 190  *
 191  * Returns zero on success, or -EFAULT on error.
 192  * On error, the variable @x is set to zero.
 193  */
 194 #define __get_user(x, ptr) \
 195         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 196
 197 #define __get_user_nocheck(x, ptr, size)                                \
 198 ({                                                                      \
 199         long __gu_err = 0;                                              \
 200         unsigned long __gu_val = 0;                                     \
 201         might_fault();                                                  \
 202         __get_user_size(__gu_val, (ptr), (size), __gu_err);             \
 203         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 204         __gu_err;                                                       \
 205 })
 206
 207 #define __get_user_check(x, ptr, size)                                  \
 208 ({                                                                      \
 209         long __gu_err = -EFAULT;                                        \
 210         unsigned long __gu_val = 0;                                     \
 211         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 212         might_fault();                                                  \
 213         if (access_ok(VERIFY_READ, __gu_addr, size))                    \
 214                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 215         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 216         __gu_err;                                                       \
 217 })
 218
 219 extern long __get_user_bad(void);
 220
 221 #define __get_user_size(x, ptr, size, retval)                           \
 222 do {                                                                    \
 223         retval = 0;                                                     \
 224         __chk_user_ptr(ptr);                                            \
 225         switch (size) {                                                 \
 226           case 1: __get_user_asm(x, ptr, retval, "ub"); break;          \
 227           case 2: __get_user_asm(x, ptr, retval, "uh"); break;          \
 228           case 4: __get_user_asm(x, ptr, retval, ""); break;            \
 229           default: (x) = __get_user_bad();                              \
 230         }                                                               \
 231 } while (0)
 232
 233 #define __get_user_asm(x, addr, err, itype)                             \
 234         __asm__ __volatile__(                                           \
 235                 "       .fillinsn\n"                                    \
 236                 "1:     ld"itype" %1,@%2\n"                             \
 237                 "       .fillinsn\n"                                    \
 238                 "2:\n"                                                  \
 239                 ".section .fixup,\"ax\"\n"                              \
 240                 "       .balign 4\n"                                    \
 241                 "3:     ldi %0,%3\n"                                    \
 242                 "       seth r14,#high(2b)\n"                           \
 243                 "       or3 r14,r14,#low(2b)\n"                         \
 244                 "       jmp r14\n"                                      \
 245                 ".previous\n"                                           \
 246                 ".section __ex_table,\"a\"\n"                           \
 247                 "       .balign 4\n"                                    \
 248                 "       .long 1b,3b\n"                                  \
 249                 ".previous"                                             \
 250                 : "=&r" (err), "=&r" (x)                                \
 251                 : "r" (addr), "i" (-EFAULT), "0" (err)                  \
 252                 : "r14", "memory")
 253
 254 /**
 255  * __put_user: - Write a simple value into user space, with less checking.
 256  * @x:   Value to copy to user space.
 257  * @ptr: Destination address, in user space.
 258  *
 259  * Context: User context only. This function may sleep if pagefaults are
 260  *          enabled.
 261  *
 262  * This macro copies a single simple value from kernel space to user
 263  * space.  It supports simple types like char and int, but not larger
 264  * data types like structures or arrays.
 265  *
 266  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 267  * to the result of dereferencing @ptr.
 268  *
 269  * Caller must check the pointer with access_ok() before calling this
 270  * function.
 271  *
 272  * Returns zero on success, or -EFAULT on error.
 273  */
 274 #define __put_user(x, ptr) \
 275         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 276
 277
 278 #define __put_user_nocheck(x, ptr, size)                                \
 279 ({                                                                      \
 280         long __pu_err;                                                  \
 281         might_fault();                                                  \
 282         __put_user_size((x), (ptr), (size), __pu_err);                  \
 283         __pu_err;                                                       \
 284 })
 285
 286
 287 #define __put_user_check(x, ptr, size)                                  \
 288 ({                                                                      \
 289         long __pu_err = -EFAULT;                                        \
 290         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 291         might_fault();                                                  \
 292         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 293                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 294         __pu_err;                                                       \
 295 })
 296
 297 #if defined(__LITTLE_ENDIAN__)
 298 #define __put_user_u64(x, addr, err)                                    \
 299         __asm__ __volatile__(                                           \
 300                 "       .fillinsn\n"                                    \
 301                 "1:     st %L1,@%2\n"                                   \
 302                 "       .fillinsn\n"                                    \
 303                 "2:     st %H1,@(4,%2)\n"                               \
 304                 "       .fillinsn\n"                                    \
 305                 "3:\n"                                                  \
 306                 ".section .fixup,\"ax\"\n"                              \
 307                 "       .balign 4\n"                                    \
 308                 "4:     ldi %0,%3\n"                                    \
 309                 "       seth r14,#high(3b)\n"                           \
 310                 "       or3 r14,r14,#low(3b)\n"                         \
 311                 "       jmp r14\n"                                      \
 312                 ".previous\n"                                           \
 313                 ".section __ex_table,\"a\"\n"                           \
 314                 "       .balign 4\n"                                    \
 315                 "       .long 1b,4b\n"                                  \
 316                 "       .long 2b,4b\n"                                  \
 317                 ".previous"                                             \
 318                 : "=&r" (err)                                           \
 319                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
 320                 : "r14", "memory")
 321
 322 #elif defined(__BIG_ENDIAN__)
 323 #define __put_user_u64(x, addr, err)                                    \
 324         __asm__ __volatile__(                                           \
 325                 "       .fillinsn\n"                                    \
 326                 "1:     st %H1,@%2\n"                                   \
 327                 "       .fillinsn\n"                                    \
 328                 "2:     st %L1,@(4,%2)\n"                               \
 329                 "       .fillinsn\n"                                    \
 330                 "3:\n"                                                  \
 331                 ".section .fixup,\"ax\"\n"                              \
 332                 "       .balign 4\n"                                    \
 333                 "4:     ldi %0,%3\n"                                    \
 334                 "       seth r14,#high(3b)\n"                           \
 335                 "       or3 r14,r14,#low(3b)\n"                         \
 336                 "       jmp r14\n"                                      \
 337                 ".previous\n"                                           \
 338                 ".section __ex_table,\"a\"\n"                           \
 339                 "       .balign 4\n"                                    \
 340                 "       .long 1b,4b\n"                                  \
 341                 "       .long 2b,4b\n"                                  \
 342                 ".previous"                                             \
 343                 : "=&r" (err)                                           \
 344                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
 345                 : "r14", "memory")
 346 #else
 347 #error no endian defined
 348 #endif
 349
 350 extern void __put_user_bad(void);
 351
 352 #define __put_user_size(x, ptr, size, retval)                           \
 353 do {                                                                    \
 354         retval = 0;                                                     \
 355         __chk_user_ptr(ptr);                                            \
 356         switch (size) {                                                 \
 357           case 1: __put_user_asm(x, ptr, retval, "b"); break;           \
 358           case 2: __put_user_asm(x, ptr, retval, "h"); break;           \
 359           case 4: __put_user_asm(x, ptr, retval, ""); break;            \
 360           case 8: __put_user_u64((__typeof__(*ptr))(x), ptr, retval); break;\
 361           default: __put_user_bad();                                    \
 362         }                                                               \
 363 } while (0)
 364
 365 struct __large_struct { unsigned long buf[100]; };
 366 #define __m(x) (*(struct __large_struct *)(x))
 367
 368 /*
 369  * Tell gcc we read from memory instead of writing: this is because
 370  * we do not write to any memory gcc knows about, so there are no
 371  * aliasing issues.
 372  */
 373 #define __put_user_asm(x, addr, err, itype)                             \
 374         __asm__ __volatile__(                                           \
 375                 "       .fillinsn\n"                                    \
 376                 "1:     st"itype" %1,@%2\n"                             \
 377                 "       .fillinsn\n"                                    \
 378                 "2:\n"                                                  \
 379                 ".section .fixup,\"ax\"\n"                              \
 380                 "       .balign 4\n"                                    \
 381                 "3:     ldi %0,%3\n"                                    \
 382                 "       seth r14,#high(2b)\n"                           \
 383                 "       or3 r14,r14,#low(2b)\n"                         \
 384                 "       jmp r14\n"                                      \
 385                 ".previous\n"                                           \
 386                 ".section __ex_table,\"a\"\n"                           \
 387                 "       .balign 4\n"                                    \
 388                 "       .long 1b,3b\n"                                  \
 389                 ".previous"                                             \
 390                 : "=&r" (err)                                           \
 391                 : "r" (x), "r" (addr), "i" (-EFAULT), "0" (err)         \
 392                 : "r14", "memory")
 393
 394 /*
 395  * Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
 396  * we return the initial request size (1, 2 or 4), as copy_*_user should do.
 397  * If a store crosses a page boundary and gets a fault, the m32r will not write
 398  * anything, so this is accurate.
 399  */
 400
 401 /*
 402  * Copy To/From Userspace
 403  */
 404
 405 /* Generic arbitrary sized copy.  */
 406 /* Return the number of bytes NOT copied.  */
 407 #define __copy_user(to, from, size)                                     \
 408 do {                                                                    \
 409         unsigned long __dst, __src, __c;                                \
 410         __asm__ __volatile__ (                                          \
 411                 "       mv      r14, %0\n"                              \
 412                 "       or      r14, %1\n"                              \
 413                 "       beq     %0, %1, 9f\n"                           \
 414                 "       beqz    %2, 9f\n"                               \
 415                 "       and3    r14, r14, #3\n"                         \
 416                 "       bnez    r14, 2f\n"                              \
 417                 "       and3    %2, %2, #3\n"                           \
 418                 "       beqz    %3, 2f\n"                               \
 419                 "       addi    %0, #-4         ; word_copy \n"         \
 420                 "       .fillinsn\n"                                    \
 421                 "0:     ld      r14, @%1+\n"                            \
 422                 "       addi    %3, #-1\n"                              \
 423                 "       .fillinsn\n"                                    \
 424                 "1:     st      r14, @+%0\n"                            \
 425                 "       bnez    %3, 0b\n"                               \
 426                 "       beqz    %2, 9f\n"                               \
 427                 "       addi    %0, #4\n"                               \
 428                 "       .fillinsn\n"                                    \
 429                 "2:     ldb     r14, @%1        ; byte_copy \n"         \
 430                 "       .fillinsn\n"                                    \
 431                 "3:     stb     r14, @%0\n"                             \
 432                 "       addi    %1, #1\n"                               \
 433                 "       addi    %2, #-1\n"                              \
 434                 "       addi    %0, #1\n"                               \
 435                 "       bnez    %2, 2b\n"                               \
 436                 "       .fillinsn\n"                                    \
 437                 "9:\n"                                                  \
 438                 ".section .fixup,\"ax\"\n"                              \
 439                 "       .balign 4\n"                                    \
 440                 "5:     addi    %3, #1\n"                               \
 441                 "       addi    %1, #-4\n"                              \
 442                 "       .fillinsn\n"                                    \
 443                 "6:     slli    %3, #2\n"                               \
 444                 "       add     %2, %3\n"                               \
 445                 "       addi    %0, #4\n"                               \
 446                 "       .fillinsn\n"                                    \
 447                 "7:     seth    r14, #high(9b)\n"                       \
 448                 "       or3     r14, r14, #low(9b)\n"                   \
 449                 "       jmp     r14\n"                                  \
 450                 ".previous\n"                                           \
 451                 ".section __ex_table,\"a\"\n"                           \
 452                 "       .balign 4\n"                                    \
 453                 "       .long 0b,6b\n"                                  \
 454                 "       .long 1b,5b\n"                                  \
 455                 "       .long 2b,9b\n"                                  \
 456                 "       .long 3b,9b\n"                                  \
 457                 ".previous\n"                                           \
 458                 : "=&r" (__dst), "=&r" (__src), "=&r" (size),           \
 459                   "=&r" (__c)                                           \
 460                 : "0" (to), "1" (from), "2" (size), "3" (size / 4)      \
 461                 : "r14", "memory");                                     \
 462 } while (0)
 463
 464 /* We let the __ versions of copy_from/to_user inline, because they're often
 465  * used in fast paths and have only a small space overhead.
 466  */
 467 static inline unsigned long
 468 raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 469 {
 470         prefetchw(to);
 471         __copy_user(to, from, n);
 472         return n;
 473 }
 474
 475 static inline unsigned long
 476 raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 477 {
 478         prefetch(from);
 479         __copy_user(to, from, n);
 480         return n;
 481 }
 482
 483 long __must_check strncpy_from_user(char *dst, const char __user *src,
 484                                 long count);
 485 long __must_check __strncpy_from_user(char *dst,
 486                                 const char __user *src, long count);
 487
 488 /**
 489  * __clear_user: - Zero a block of memory in user space, with less checking.
 490  * @to:   Destination address, in user space.
 491  * @n:    Number of bytes to zero.
 492  *
 493  * Zero a block of memory in user space.  Caller must check
 494  * the specified block with access_ok() before calling this function.
 495  *
 496  * Returns number of bytes that could not be cleared.
 497  * On success, this will be zero.
 498  */
 499 unsigned long __clear_user(void __user *mem, unsigned long len);
 500
 501 /**
 502  * clear_user: - Zero a block of memory in user space.
 503  * @to:   Destination address, in user space.
 504  * @n:    Number of bytes to zero.
 505  *
 506  * Zero a block of memory in user space.  Caller must check
 507  * the specified block with access_ok() before calling this function.
 508  *
 509  * Returns number of bytes that could not be cleared.
 510  * On success, this will be zero.
 511  */
 512 unsigned long clear_user(void __user *mem, unsigned long len);
 513
 514 /**
 515  * strlen_user: - Get the size of a string in user space.
 516  * @str: The string to measure.
 517  *
 518  * Context: User context only. This function may sleep if pagefaults are
 519  *          enabled.
 520  *
 521  * Get the size of a NUL-terminated string in user space.
 522  *
 523  * Returns the size of the string INCLUDING the terminating NUL.
 524  * On exception, returns 0.
 525  *
 526  * If there is a limit on the length of a valid string, you may wish to
 527  * consider using strnlen_user() instead.
 528  */
 529 #define strlen_user(str) strnlen_user(str, ~0UL >> 1)
 530 long strnlen_user(const char __user *str, long n);
 531
 532 #endif /* _ASM_M32R_UACCESS_H */