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) > memory_end));
  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 /*
  94  * Address is valid if:
  95  *  - "addr", "addr + size" and "size" are all below the limit
  96  */
  97 #define access_ok(type, addr, size) \
  98         (get_fs().seg > (((unsigned long)(addr)) | \
  99                 (size) | ((unsigned long)(addr) + (size))))
 100
 101 /* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
 102  type?"WRITE":"READ",addr,size,get_fs().seg)) */
 103
 104 #endif
 105
 106 #ifdef CONFIG_MMU
 107 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
 108 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
 109 #else
 110 # define __FIXUP_SECTION        ".section .discard,\"ax\"\n"
 111 # define __EX_TABLE_SECTION     ".section .discard,\"a\"\n"
 112 #endif
 113
 114 extern unsigned long __copy_tofrom_user(void __user *to,
 115                 const void __user *from, unsigned long size);
 116
 117 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
 118 static inline unsigned long __must_check __clear_user(void __user *to,
 119                                                         unsigned long n)
 120 {
 121         /* normal memset with two words to __ex_table */
 122         __asm__ __volatile__ (                          \
 123                         "1:     sb      r0, %2, r0;"    \
 124                         "       addik   %0, %0, -1;"    \
 125                         "       bneid   %0, 1b;"        \
 126                         "       addik   %2, %2, 1;"     \
 127                         "2:                     "       \
 128                         __EX_TABLE_SECTION              \
 129                         ".word  1b,2b;"                 \
 130                         ".previous;"                    \
 131                 : "=r"(n)                               \
 132                 : "0"(n), "r"(to)
 133         );
 134         return n;
 135 }
 136
 137 static inline unsigned long __must_check clear_user(void __user *to,
 138                                                         unsigned long n)
 139 {
 140         might_sleep();
 141         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 142                 return n;
 143
 144         return __clear_user(to, n);
 145 }
 146
 147 #ifndef CONFIG_MMU
 148
 149 /* Undefined function to trigger linker error */
 150 extern int bad_user_access_length(void);
 151
 152 /* FIXME this is function for optimalization -> memcpy */
 153 #define __get_user(var, ptr)                            \
 154 ({                                                      \
 155         int __gu_err = 0;                               \
 156         switch (sizeof(*(ptr))) {                       \
 157         case 1:                                         \
 158         case 2:                                         \
 159         case 4:                                         \
 160                 (var) = *(ptr);                         \
 161                 break;                                  \
 162         case 8:                                         \
 163                 memcpy((void *) &(var), (ptr), 8);      \
 164                 break;                                  \
 165         default:                                        \
 166                 (var) = 0;                              \
 167                 __gu_err = __get_user_bad();            \
 168                 break;                                  \
 169         }                                               \
 170         __gu_err;                                       \
 171 })
 172
 173 #define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
 174
 175 /* FIXME is not there defined __pu_val */
 176 #define __put_user(var, ptr)                                    \
 177 ({                                                              \
 178         int __pu_err = 0;                                       \
 179         switch (sizeof(*(ptr))) {                               \
 180         case 1:                                                 \
 181         case 2:                                                 \
 182         case 4:                                                 \
 183                 *(ptr) = (var);                                 \
 184                 break;                                          \
 185         case 8: {                                               \
 186                 typeof(*(ptr)) __pu_val = (var);                \
 187                 memcpy(ptr, &__pu_val, sizeof(__pu_val));       \
 188                 }                                               \
 189                 break;                                          \
 190         default:                                                \
 191                 __pu_err = __put_user_bad();                    \
 192                 break;                                          \
 193         }                                                       \
 194         __pu_err;                                               \
 195 })
 196
 197 #define __put_user_bad()        (bad_user_access_length(), (-EFAULT))
 198
 199 #define put_user(x, ptr)        __put_user((x), (ptr))
 200 #define get_user(x, ptr)        __get_user((x), (ptr))
 201
 202 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
 203 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)
 204
 205 #define __copy_to_user(to, from, n)     (copy_to_user((to), (from), (n)))
 206 #define __copy_from_user(to, from, n)   (copy_from_user((to), (from), (n)))
 207 #define __copy_to_user_inatomic(to, from, n) \
 208                         (__copy_to_user((to), (from), (n)))
 209 #define __copy_from_user_inatomic(to, from, n) \
 210                         (__copy_from_user((to), (from), (n)))
 211
 212 extern long strncpy_from_user(char *dst, const char *src, long count);
 213 extern long strnlen_user(const char *src, long count);
 214
 215 #else /* CONFIG_MMU */
 216
 217 /* put_user and get_user macros */
 218
 219 extern long __user_bad(void);
 220
 221 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 222 ({                                                              \
 223         __asm__ __volatile__ (                                  \
 224                         "1:"    insn    " %1, %2, r0;"          \
 225                         "       addk    %0, r0, r0;"            \
 226                         "2:                     "               \
 227                         __FIXUP_SECTION                         \
 228                         "3:     brid    2b;     "               \
 229                         "       addik   %0, r0, %3;"            \
 230                         ".previous;"                            \
 231                         __EX_TABLE_SECTION                      \
 232                         ".word  1b,3b;"                         \
 233                         ".previous;"                            \
 234                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 235                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 236         );                                                      \
 237 })
 238
 239 #define __get_user(x, ptr)                                              \
 240 ({                                                                      \
 241         unsigned long __gu_val;                                         \
 242         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 243         long __gu_err;                                                  \
 244         switch (sizeof(*(ptr))) {                                       \
 245         case 1:                                                         \
 246                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 247                 break;                                                  \
 248         case 2:                                                         \
 249                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 250                 break;                                                  \
 251         case 4:                                                         \
 252                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 253                 break;                                                  \
 254         default:                                                        \
 255                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 256         }                                                               \
 257         x = (__typeof__(*(ptr))) __gu_val;                              \
 258         __gu_err;                                                       \
 259 })
 260
 261 /**
 262  * get_user: - Get a simple variable from user space.
 263  * @x:   Variable to store result.
 264  * @ptr: Source address, in user space.
 265  *
 266  * Context: User context only.  This function may sleep.
 267  *
 268  * This macro copies a single simple variable from user space to kernel
 269  * space.  It supports simple types like char and int, but not larger
 270  * data types like structures or arrays.
 271  *
 272  * @ptr must have pointer-to-simple-variable type, and the result of
 273  * dereferencing @ptr must be assignable to @x without a cast.
 274  *
 275  * Returns zero on success, or -EFAULT on error.
 276  * On error, the variable @x is set to zero.
 277  */
 278
 279 #define get_user(x, ptr)                                                \
 280 ({                                                                      \
 281         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
 282                 ? __get_user((x), (ptr)) : -EFAULT;                     \
 283 })
 284
 285 /**
 286  * put_user: - Write a simple value into user space.
 287  * @x:   Value to copy to user space.
 288  * @ptr: Destination address, in user space.
 289  *
 290  * Context: User context only.  This function may sleep.
 291  *
 292  * This macro copies a single simple value from kernel space to user
 293  * space.  It supports simple types like char and int, but not larger
 294  * data types like structures or arrays.
 295  *
 296  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 297  * to the result of dereferencing @ptr.
 298  *
 299  * Returns zero on success, or -EFAULT on error.
 300  */
 301
 302 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 303 ({                                                              \
 304         __asm__ __volatile__ (                                  \
 305                         "1:"    insn    " %1, %2, r0;"          \
 306                         "       addk    %0, r0, r0;"            \
 307                         "2:                     "               \
 308                         __FIXUP_SECTION                         \
 309                         "3:     brid    2b;"                    \
 310                         "       addik   %0, r0, %3;"            \
 311                         ".previous;"                            \
 312                         __EX_TABLE_SECTION                      \
 313                         ".word  1b,3b;"                         \
 314                         ".previous;"                            \
 315                 : "=&r"(__gu_err)                               \
 316                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 317         );                                                      \
 318 })
 319
 320 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 321 ({                                                              \
 322         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 323                         "1:     swi     %0, %2, 0;"             \
 324                         "       lwi     %0, %1, 4;"             \
 325                         "2:     swi     %0, %2, 4;"             \
 326                         "       addk    %0, r0, r0;"            \
 327                         "3:                             "       \
 328                         __FIXUP_SECTION                         \
 329                         "4:     brid    3b;"                    \
 330                         "       addik   %0, r0, %3;"            \
 331                         ".previous;"                            \
 332                         __EX_TABLE_SECTION                      \
 333                         ".word  1b,4b,2b,4b;"                   \
 334                         ".previous;"                            \
 335                 : "=&r"(__gu_err)                               \
 336                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 337                 );                                              \
 338 })
 339
 340 #define __put_user(x, ptr)                                              \
 341 ({                                                                      \
 342         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 343         long __gu_err = 0;                                              \
 344         switch (sizeof(__gu_val)) {                                     \
 345         case 1:                                                         \
 346                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 347                 break;                                                  \
 348         case 2:                                                         \
 349                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 350                 break;                                                  \
 351         case 4:                                                         \
 352                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 353                 break;                                                  \
 354         case 8:                                                         \
 355                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 356                 break;                                                  \
 357         default:                                                        \
 358                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 359         }                                                               \
 360         __gu_err;                                                       \
 361 })
 362
 363 #define put_user(x, ptr)                                                \
 364 ({                                                                      \
 365         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
 366                 ? __put_user((x), (ptr)) : -EFAULT;                     \
 367 })
 368
 369 #define __copy_from_user(to, from, n)   \
 370         __copy_tofrom_user((__force void __user *)(to), \
 371                                 (void __user *)(from), (n))
 372 #define __copy_from_user_inatomic(to, from, n) \
 373                 copy_from_user((to), (from), (n))
 374
 375 static inline long copy_from_user(void *to,
 376                 const void __user *from, unsigned long n)
 377 {
 378         might_sleep();
 379         if (access_ok(VERIFY_READ, from, n))
 380                 return __copy_from_user(to, from, n);
 381         else
 382                 return n;
 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_sleep();
 394         if (access_ok(VERIFY_WRITE, to, n))
 395                 return __copy_to_user(to, from, n);
 396         else
 397                 return n;
 398 }
 399
 400 extern int __strncpy_user(char *to, const char __user *from, int len);
 401
 402 #define __strncpy_from_user     __strncpy_user
 403
 404 static inline long
 405 strncpy_from_user(char *dst, const char __user *src, long count)
 406 {
 407         if (!access_ok(VERIFY_READ, src, 1))
 408                 return -EFAULT;
 409         return __strncpy_from_user(dst, src, count);
 410 }
 411
 412 extern int __strnlen_user(const char __user *sstr, int len);
 413
 414 #define strnlen_user(str, len)  \
 415                 (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)
 416
 417 #endif /* CONFIG_MMU */
 418
 419 #endif  /* __ASSEMBLY__ */
 420 #endif /* __KERNEL__ */
 421
 422 #endif /* _ASM_MICROBLAZE_UACCESS_H */