arch/microblaze/include/asm/uaccess.h

   1 /*
   2  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   3  * Copyright (C) 2008-2009 PetaLogix
   4  * Copyright (C) 2006 Atmark Techno, Inc.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License. See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #ifndef _ASM_MICROBLAZE_UACCESS_H
  12 #define _ASM_MICROBLAZE_UACCESS_H
  13
  14 #ifdef __KERNEL__
  15 #ifndef __ASSEMBLY__
  16
  17 #include <linux/kernel.h>
  18 #include <linux/errno.h>
  19 #include <linux/sched.h> /* RLIMIT_FSIZE */
  20 #include <linux/mm.h>
  21
  22 #include <asm/mmu.h>
  23 #include <asm/page.h>
  24 #include <asm/pgtable.h>
  25 #include <linux/string.h>
  26
  27 #define VERIFY_READ     0
  28 #define VERIFY_WRITE    1
  29
  30 /*
  31  * On Microblaze the fs value is actually the top of the corresponding
  32  * address space.
  33  *
  34  * The fs value determines whether argument validity checking should be
  35  * performed or not. If get_fs() == USER_DS, checking is performed, with
  36  * get_fs() == KERNEL_DS, checking is bypassed.
  37  *
  38  * For historical reasons, these macros are grossly misnamed.
  39  *
  40  * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
  41  */
  42 # define MAKE_MM_SEG(s)       ((mm_segment_t) { (s) })
  43
  44 #  ifndef CONFIG_MMU
  45 #  define KERNEL_DS     MAKE_MM_SEG(0)
  46 #  define USER_DS       KERNEL_DS
  47 #  else
  48 #  define KERNEL_DS     MAKE_MM_SEG(0xFFFFFFFF)
  49 #  define USER_DS       MAKE_MM_SEG(TASK_SIZE - 1)
  50 #  endif
  51
  52 # define get_ds()       (KERNEL_DS)
  53 # define get_fs()       (current_thread_info()->addr_limit)
  54 # define set_fs(val)    (current_thread_info()->addr_limit = (val))
  55
  56 # define segment_eq(a, b)       ((a).seg == (b).seg)
  57
  58 /*
  59  * The exception table consists of pairs of addresses: the first is the
  60  * address of an instruction that is allowed to fault, and the second is
  61  * the address at which the program should continue. No registers are
  62  * modified, so it is entirely up to the continuation code to figure out
  63  * what to do.
  64  *
  65  * All the routines below use bits of fixup code that are out of line
  66  * with the main instruction path. This means when everything is well,
  67  * we don't even have to jump over them. Further, they do not intrude
  68  * on our cache or tlb entries.
  69  */
  70 struct exception_table_entry {
  71         unsigned long insn, fixup;
  72 };
  73
  74 /* Returns 0 if exception not found and fixup otherwise.  */
  75 extern unsigned long search_exception_table(unsigned long);
  76
  77 #ifndef CONFIG_MMU
  78
  79 /* Check against bounds of physical memory */
  80 static inline int ___range_ok(unsigned long addr, unsigned long size)
  81 {
  82         return ((addr < memory_start) ||
  83                 ((addr + size - 1) > (memory_start + memory_size - 1)));
  84 }
  85
  86 #define __range_ok(addr, size) \
  87                 ___range_ok((unsigned long)(addr), (unsigned long)(size))
  88
  89 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
  90
  91 #else
  92
  93 static inline int access_ok(int type, const void __user *addr,
  94                                                         unsigned long size)
  95 {
  96         if (!size)
  97                 goto ok;
  98
  99         if ((get_fs().seg < ((unsigned long)addr)) ||
 100                         (get_fs().seg < ((unsigned long)addr + size - 1))) {
 101                 pr_devel("ACCESS fail: %s at 0x%08x (size 0x%x), seg 0x%08x\n",
 102                         type ? "WRITE" : "READ ", (__force u32)addr, (u32)size,
 103                         (u32)get_fs().seg);
 104                 return 0;
 105         }
 106 ok:
 107         pr_devel("ACCESS OK: %s at 0x%08x (size 0x%x), seg 0x%08x\n",
 108                         type ? "WRITE" : "READ ", (__force u32)addr, (u32)size,
 109                         (u32)get_fs().seg);
 110         return 1;
 111 }
 112 #endif
 113
 114 #ifdef CONFIG_MMU
 115 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
 116 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
 117 #else
 118 # define __FIXUP_SECTION        ".section .discard,\"ax\"\n"
 119 # define __EX_TABLE_SECTION     ".section .discard,\"ax\"\n"
 120 #endif
 121
 122 extern unsigned long __copy_tofrom_user(void __user *to,
 123                 const void __user *from, unsigned long size);
 124
 125 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
 126 static inline unsigned long __must_check __clear_user(void __user *to,
 127                                                         unsigned long n)
 128 {
 129         /* normal memset with two words to __ex_table */
 130         __asm__ __volatile__ (                          \
 131                         "1:     sb      r0, %1, r0;"    \
 132                         "       addik   %0, %0, -1;"    \
 133                         "       bneid   %0, 1b;"        \
 134                         "       addik   %1, %1, 1;"     \
 135                         "2:                     "       \
 136                         __EX_TABLE_SECTION              \
 137                         ".word  1b,2b;"                 \
 138                         ".previous;"                    \
 139                 : "=r"(n), "=r"(to)                     \
 140                 : "0"(n), "1"(to)
 141         );
 142         return n;
 143 }
 144
 145 static inline unsigned long __must_check clear_user(void __user *to,
 146                                                         unsigned long n)
 147 {
 148         might_fault();
 149         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 150                 return n;
 151
 152         return __clear_user(to, n);
 153 }
 154
 155 /* put_user and get_user macros */
 156 extern long __user_bad(void);
 157
 158 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 159 ({                                                              \
 160         __asm__ __volatile__ (                                  \
 161                         "1:"    insn    " %1, %2, r0;"          \
 162                         "       addk    %0, r0, r0;"            \
 163                         "2:                     "               \
 164                         __FIXUP_SECTION                         \
 165                         "3:     brid    2b;"                    \
 166                         "       addik   %0, r0, %3;"            \
 167                         ".previous;"                            \
 168                         __EX_TABLE_SECTION                      \
 169                         ".word  1b,3b;"                         \
 170                         ".previous;"                            \
 171                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 172                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 173         );                                                      \
 174 })
 175
 176 /**
 177  * get_user: - Get a simple variable from user space.
 178  * @x:   Variable to store result.
 179  * @ptr: Source address, in user space.
 180  *
 181  * Context: User context only. This function may sleep if pagefaults are
 182  *          enabled.
 183  *
 184  * This macro copies a single simple variable from user space to kernel
 185  * space.  It supports simple types like char and int, but not larger
 186  * data types like structures or arrays.
 187  *
 188  * @ptr must have pointer-to-simple-variable type, and the result of
 189  * dereferencing @ptr must be assignable to @x without a cast.
 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_check((x), (ptr), sizeof(*(ptr)))
 196
 197 #define __get_user_check(x, ptr, size)                                  \
 198 ({                                                                      \
 199         unsigned long __gu_val = 0;                                     \
 200         const typeof(*(ptr)) __user *__gu_addr = (ptr);                 \
 201         int __gu_err = 0;                                               \
 202                                                                         \
 203         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 204                 switch (size) {                                         \
 205                 case 1:                                                 \
 206                         __get_user_asm("lbu", __gu_addr, __gu_val,      \
 207                                        __gu_err);                       \
 208                         break;                                          \
 209                 case 2:                                                 \
 210                         __get_user_asm("lhu", __gu_addr, __gu_val,      \
 211                                        __gu_err);                       \
 212                         break;                                          \
 213                 case 4:                                                 \
 214                         __get_user_asm("lw", __gu_addr, __gu_val,       \
 215                                        __gu_err);                       \
 216                         break;                                          \
 217                 default:                                                \
 218                         __gu_err = __user_bad();                        \
 219                         break;                                          \
 220                 }                                                       \
 221         } else {                                                        \
 222                 __gu_err = -EFAULT;                                     \
 223         }                                                               \
 224         x = (__force typeof(*(ptr)))__gu_val;                           \
 225         __gu_err;                                                       \
 226 })
 227
 228 #define __get_user(x, ptr)                                              \
 229 ({                                                                      \
 230         unsigned long __gu_val = 0;                                     \
 231         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 232         long __gu_err;                                                  \
 233         switch (sizeof(*(ptr))) {                                       \
 234         case 1:                                                         \
 235                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 236                 break;                                                  \
 237         case 2:                                                         \
 238                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 239                 break;                                                  \
 240         case 4:                                                         \
 241                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 242                 break;                                                  \
 243         default:                                                        \
 244                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 245         }                                                               \
 246         x = (__force __typeof__(*(ptr))) __gu_val;                      \
 247         __gu_err;                                                       \
 248 })
 249
 250
 251 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 252 ({                                                              \
 253         __asm__ __volatile__ (                                  \
 254                         "1:"    insn    " %1, %2, r0;"          \
 255                         "       addk    %0, r0, r0;"            \
 256                         "2:                     "               \
 257                         __FIXUP_SECTION                         \
 258                         "3:     brid    2b;"                    \
 259                         "       addik   %0, r0, %3;"            \
 260                         ".previous;"                            \
 261                         __EX_TABLE_SECTION                      \
 262                         ".word  1b,3b;"                         \
 263                         ".previous;"                            \
 264                 : "=&r"(__gu_err)                               \
 265                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 266         );                                                      \
 267 })
 268
 269 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 270 ({                                                              \
 271         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 272                         "1:     swi     %0, %2, 0;"             \
 273                         "       lwi     %0, %1, 4;"             \
 274                         "2:     swi     %0, %2, 4;"             \
 275                         "       addk    %0, r0, r0;"            \
 276                         "3:                     "               \
 277                         __FIXUP_SECTION                         \
 278                         "4:     brid    3b;"                    \
 279                         "       addik   %0, r0, %3;"            \
 280                         ".previous;"                            \
 281                         __EX_TABLE_SECTION                      \
 282                         ".word  1b,4b,2b,4b;"                   \
 283                         ".previous;"                            \
 284                 : "=&r"(__gu_err)                               \
 285                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 286                 );                                              \
 287 })
 288
 289 /**
 290  * put_user: - Write a simple value into user space.
 291  * @x:   Value to copy to user space.
 292  * @ptr: Destination address, in user space.
 293  *
 294  * Context: User context only. This function may sleep if pagefaults are
 295  *          enabled.
 296  *
 297  * This macro copies a single simple value from kernel space to user
 298  * space.  It supports simple types like char and int, but not larger
 299  * data types like structures or arrays.
 300  *
 301  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 302  * to the result of dereferencing @ptr.
 303  *
 304  * Returns zero on success, or -EFAULT on error.
 305  */
 306 #define put_user(x, ptr)                                                \
 307         __put_user_check((x), (ptr), sizeof(*(ptr)))
 308
 309 #define __put_user_check(x, ptr, size)                                  \
 310 ({                                                                      \
 311         typeof(*(ptr)) volatile __pu_val = x;                           \
 312         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 313         int __pu_err = 0;                                               \
 314                                                                         \
 315         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 316                 switch (size) {                                         \
 317                 case 1:                                                 \
 318                         __put_user_asm("sb", __pu_addr, __pu_val,       \
 319                                        __pu_err);                       \
 320                         break;                                          \
 321                 case 2:                                                 \
 322                         __put_user_asm("sh", __pu_addr, __pu_val,       \
 323                                        __pu_err);                       \
 324                         break;                                          \
 325                 case 4:                                                 \
 326                         __put_user_asm("sw", __pu_addr, __pu_val,       \
 327                                        __pu_err);                       \
 328                         break;                                          \
 329                 case 8:                                                 \
 330                         __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
 331                         break;                                          \
 332                 default:                                                \
 333                         __pu_err = __user_bad();                        \
 334                         break;                                          \
 335                 }                                                       \
 336         } else {                                                        \
 337                 __pu_err = -EFAULT;                                     \
 338         }                                                               \
 339         __pu_err;                                                       \
 340 })
 341
 342 #define __put_user(x, ptr)                                              \
 343 ({                                                                      \
 344         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 345         long __gu_err = 0;                                              \
 346         switch (sizeof(__gu_val)) {                                     \
 347         case 1:                                                         \
 348                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 349                 break;                                                  \
 350         case 2:                                                         \
 351                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 352                 break;                                                  \
 353         case 4:                                                         \
 354                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 355                 break;                                                  \
 356         case 8:                                                         \
 357                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 358                 break;                                                  \
 359         default:                                                        \
 360                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 361         }                                                               \
 362         __gu_err;                                                       \
 363 })
 364
 365
 366 /* copy_to_from_user */
 367 #define __copy_from_user(to, from, n)   \
 368         __copy_tofrom_user((__force void __user *)(to), \
 369                                 (void __user *)(from), (n))
 370 #define __copy_from_user_inatomic(to, from, n) \
 371                 __copy_from_user((to), (from), (n))
 372
 373 static inline long copy_from_user(void *to,
 374                 const void __user *from, unsigned long n)
 375 {
 376         unsigned long res = n;
 377         might_fault();
 378         if (likely(access_ok(VERIFY_READ, from, n)))
 379                 res = __copy_from_user(to, from, n);
 380         if (unlikely(res))
 381                 memset(to + (n - res), 0, res);
 382         return res;
 383 }
 384
 385 #define __copy_to_user(to, from, n)     \
 386                 __copy_tofrom_user((void __user *)(to), \
 387                         (__force const void __user *)(from), (n))
 388 #define __copy_to_user_inatomic(to, from, n) __copy_to_user((to), (from), (n))
 389
 390 static inline long copy_to_user(void __user *to,
 391                 const void *from, unsigned long n)
 392 {
 393         might_fault();
 394         if (access_ok(VERIFY_WRITE, to, n))
 395                 return __copy_to_user(to, from, n);
 396         return n;
 397 }
 398
 399 /*
 400  * Copy a null terminated string from userspace.
 401  */
 402 extern int __strncpy_user(char *to, const char __user *from, int len);
 403
 404 #define __strncpy_from_user     __strncpy_user
 405
 406 static inline long
 407 strncpy_from_user(char *dst, const char __user *src, long count)
 408 {
 409         if (!access_ok(VERIFY_READ, src, 1))
 410                 return -EFAULT;
 411         return __strncpy_from_user(dst, src, count);
 412 }
 413
 414 /*
 415  * Return the size of a string (including the ending 0)
 416  *
 417  * Return 0 on exception, a value greater than N if too long
 418  */
 419 extern int __strnlen_user(const char __user *sstr, int len);
 420
 421 static inline long strnlen_user(const char __user *src, long n)
 422 {
 423         if (!access_ok(VERIFY_READ, src, 1))
 424                 return 0;
 425         return __strnlen_user(src, n);
 426 }
 427
 428 #endif  /* __ASSEMBLY__ */
 429 #endif /* __KERNEL__ */
 430
 431 #endif /* _ASM_MICROBLAZE_UACCESS_H */