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   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 #ifndef CONFIG_MMU
  75
  76 /* Check against bounds of physical memory */
  77 static inline int ___range_ok(unsigned long addr, unsigned long size)
  78 {
  79         return ((addr < memory_start) ||
  80                 ((addr + size) > memory_end));
  81 }
  82
  83 #define __range_ok(addr, size) \
  84                 ___range_ok((unsigned long)(addr), (unsigned long)(size))
  85
  86 #define access_ok(type, addr, size) (__range_ok((addr), (size)) == 0)
  87
  88 #else
  89
  90 /*
  91  * Address is valid if:
  92  *  - "addr", "addr + size" and "size" are all below the limit
  93  */
  94 #define access_ok(type, addr, size) \
  95         (get_fs().seg > (((unsigned long)(addr)) | \
  96                 (size) | ((unsigned long)(addr) + (size))))
  97
  98 /* || printk("access_ok failed for %s at 0x%08lx (size %d), seg 0x%08x\n",
  99  type?"WRITE":"READ",addr,size,get_fs().seg)) */
 100
 101 #endif
 102
 103 #ifdef CONFIG_MMU
 104 # define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
 105 # define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
 106 #else
 107 # define __FIXUP_SECTION        ".section .discard,\"ax\"\n"
 108 # define __EX_TABLE_SECTION     ".section .discard,\"a\"\n"
 109 #endif
 110
 111 #ifndef CONFIG_MMU
 112
 113 /* Undefined function to trigger linker error */
 114 extern int bad_user_access_length(void);
 115
 116 /* FIXME this is function for optimalization -> memcpy */
 117 #define __get_user(var, ptr)                            \
 118 ({                                                      \
 119         int __gu_err = 0;                               \
 120         switch (sizeof(*(ptr))) {                       \
 121         case 1:                                         \
 122         case 2:                                         \
 123         case 4:                                         \
 124                 (var) = *(ptr);                         \
 125                 break;                                  \
 126         case 8:                                         \
 127                 memcpy((void *) &(var), (ptr), 8);      \
 128                 break;                                  \
 129         default:                                        \
 130                 (var) = 0;                              \
 131                 __gu_err = __get_user_bad();            \
 132                 break;                                  \
 133         }                                               \
 134         __gu_err;                                       \
 135 })
 136
 137 #define __get_user_bad()        (bad_user_access_length(), (-EFAULT))
 138
 139 /* FIXME is not there defined __pu_val */
 140 #define __put_user(var, ptr)                                    \
 141 ({                                                              \
 142         int __pu_err = 0;                                       \
 143         switch (sizeof(*(ptr))) {                               \
 144         case 1:                                                 \
 145         case 2:                                                 \
 146         case 4:                                                 \
 147                 *(ptr) = (var);                                 \
 148                 break;                                          \
 149         case 8: {                                               \
 150                 typeof(*(ptr)) __pu_val = (var);                \
 151                 memcpy(ptr, &__pu_val, sizeof(__pu_val));       \
 152                 }                                               \
 153                 break;                                          \
 154         default:                                                \
 155                 __pu_err = __put_user_bad();                    \
 156                 break;                                          \
 157         }                                                       \
 158         __pu_err;                                               \
 159 })
 160
 161 #define __put_user_bad()        (bad_user_access_length(), (-EFAULT))
 162
 163 #define put_user(x, ptr)        __put_user((x), (ptr))
 164 #define get_user(x, ptr)        __get_user((x), (ptr))
 165
 166 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
 167 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)
 168
 169 #define __copy_to_user(to, from, n)     (copy_to_user((to), (from), (n)))
 170 #define __copy_from_user(to, from, n)   (copy_from_user((to), (from), (n)))
 171 #define __copy_to_user_inatomic(to, from, n) \
 172                         (__copy_to_user((to), (from), (n)))
 173 #define __copy_from_user_inatomic(to, from, n) \
 174                         (__copy_from_user((to), (from), (n)))
 175
 176 #define __clear_user(addr, n)   (memset((void *)(addr), 0, (n)), 0)
 177
 178 /* stejne s MMU */
 179 static inline unsigned long clear_user(void *addr, unsigned long size)
 180 {
 181         if (access_ok(VERIFY_WRITE, addr, size))
 182                 size = __clear_user(addr, size);
 183         return size;
 184 }
 185
 186 /* Returns 0 if exception not found and fixup otherwise.  */
 187 extern unsigned long search_exception_table(unsigned long);
 188
 189 extern long strncpy_from_user(char *dst, const char *src, long count);
 190 extern long strnlen_user(const char *src, long count);
 191
 192 #else /* CONFIG_MMU */
 193
 194 /*
 195  * All the __XXX versions macros/functions below do not perform
 196  * access checking. It is assumed that the necessary checks have been
 197  * already performed before the finction (macro) is called.
 198  */
 199
 200 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 201 ({                                                              \
 202         __asm__ __volatile__ (                                  \
 203                         "1:"    insn    " %1, %2, r0;"          \
 204                         "       addk    %0, r0, r0;"            \
 205                         "2:                     "               \
 206                         __FIXUP_SECTION                         \
 207                         "3:     brid    2b;     "               \
 208                         "       addik   %0, r0, %3;"            \
 209                         ".previous;"                            \
 210                         __EX_TABLE_SECTION                      \
 211                         ".word  1b,3b;"                         \
 212                         ".previous;"                            \
 213                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 214                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 215         );                                                      \
 216 })
 217
 218 #define __get_user(x, ptr)                                              \
 219 ({                                                                      \
 220         unsigned long __gu_val;                                         \
 221         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 222         long __gu_err;                                                  \
 223         switch (sizeof(*(ptr))) {                                       \
 224         case 1:                                                         \
 225                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 226                 break;                                                  \
 227         case 2:                                                         \
 228                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 229                 break;                                                  \
 230         case 4:                                                         \
 231                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 232                 break;                                                  \
 233         default:                                                        \
 234                 __gu_val = 0; __gu_err = -EINVAL;                       \
 235         }                                                               \
 236         x = (__typeof__(*(ptr))) __gu_val;                              \
 237         __gu_err;                                                       \
 238 })
 239
 240 #define get_user(x, ptr)                                                \
 241 ({                                                                      \
 242         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
 243                 ? __get_user((x), (ptr)) : -EFAULT;                     \
 244 })
 245
 246 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 247 ({                                                              \
 248         __asm__ __volatile__ (                                  \
 249                         "1:"    insn    " %1, %2, r0;"          \
 250                         "       addk    %0, r0, r0;"            \
 251                         "2:                     "               \
 252                         __FIXUP_SECTION                         \
 253                         "3:     brid    2b;"                    \
 254                         "       addik   %0, r0, %3;"            \
 255                         ".previous;"                            \
 256                         __EX_TABLE_SECTION                      \
 257                         ".word  1b,3b;"                         \
 258                         ".previous;"                            \
 259                 : "=&r"(__gu_err)                               \
 260                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 261         );                                                      \
 262 })
 263
 264 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 265 ({                                                              \
 266         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 267                         "1:     swi     %0, %2, 0;"             \
 268                         "       lwi     %0, %1, 4;"             \
 269                         "2:     swi     %0, %2, 4;"             \
 270                         "       addk    %0, r0, r0;"            \
 271                         "3:                             "       \
 272                         __FIXUP_SECTION                         \
 273                         "4:     brid    3b;"                    \
 274                         "       addik   %0, r0, %3;"            \
 275                         ".previous;"                            \
 276                         __EX_TABLE_SECTION                      \
 277                         ".word  1b,4b,2b,4b;"                   \
 278                         ".previous;"                            \
 279                 : "=&r"(__gu_err)                               \
 280                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 281                 );                                              \
 282 })
 283
 284 #define __put_user(x, ptr)                                              \
 285 ({                                                                      \
 286         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 287         long __gu_err = 0;                                              \
 288         switch (sizeof(__gu_val)) {                                     \
 289         case 1:                                                         \
 290                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 291                 break;                                                  \
 292         case 2:                                                         \
 293                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 294                 break;                                                  \
 295         case 4:                                                         \
 296                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 297                 break;                                                  \
 298         case 8:                                                         \
 299                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 300                 break;                                                  \
 301         default:                                                        \
 302                 __gu_err = -EINVAL;                                     \
 303         }                                                               \
 304         __gu_err;                                                       \
 305 })
 306
 307 #define put_user(x, ptr)                                                \
 308 ({                                                                      \
 309         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
 310                 ? __put_user((x), (ptr)) : -EFAULT;                     \
 311 })
 312
 313 /* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
 314 static inline unsigned long __must_check __clear_user(void __user *to,
 315                                                         unsigned long n)
 316 {
 317         /* normal memset with two words to __ex_table */
 318         __asm__ __volatile__ (                          \
 319                         "1:     sb      r0, %2, r0;"    \
 320                         "       addik   %0, %0, -1;"    \
 321                         "       bneid   %0, 1b;"        \
 322                         "       addik   %2, %2, 1;"     \
 323                         "2:                     "       \
 324                         __EX_TABLE_SECTION              \
 325                         ".word  1b,2b;"                 \
 326                         ".previous;"                    \
 327                 : "=r"(n)                               \
 328                 : "0"(n), "r"(to)
 329         );
 330         return n;
 331 }
 332
 333 static inline unsigned long __must_check clear_user(void __user *to,
 334                                                         unsigned long n)
 335 {
 336         might_sleep();
 337         if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
 338                 return n;
 339
 340         return __clear_user(to, n);
 341 }
 342
 343 #define __copy_from_user(to, from, n)   copy_from_user((to), (from), (n))
 344 #define __copy_from_user_inatomic(to, from, n) \
 345                 copy_from_user((to), (from), (n))
 346
 347 #define copy_to_user(to, from, n)                                       \
 348         (access_ok(VERIFY_WRITE, (to), (n)) ?                           \
 349                 __copy_tofrom_user((void __user *)(to),                 \
 350                         (__force const void __user *)(from), (n))       \
 351                 : -EFAULT)
 352
 353 #define __copy_to_user(to, from, n)     copy_to_user((to), (from), (n))
 354 #define __copy_to_user_inatomic(to, from, n)    copy_to_user((to), (from), (n))
 355
 356 #define copy_from_user(to, from, n)                                     \
 357         (access_ok(VERIFY_READ, (from), (n)) ?                          \
 358                 __copy_tofrom_user((__force void __user *)(to),         \
 359                         (void __user *)(from), (n))                     \
 360                 : -EFAULT)
 361
 362 extern int __strncpy_user(char *to, const char __user *from, int len);
 363 extern int __strnlen_user(const char __user *sstr, int len);
 364
 365 #define strncpy_from_user(to, from, len)        \
 366                 (access_ok(VERIFY_READ, from, 1) ?      \
 367                         __strncpy_user(to, from, len) : -EFAULT)
 368 #define strnlen_user(str, len)  \
 369                 (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)
 370
 371 #endif /* CONFIG_MMU */
 372
 373 extern unsigned long __copy_tofrom_user(void __user *to,
 374                 const void __user *from, unsigned long size);
 375
 376 #endif  /* __ASSEMBLY__ */
 377 #endif /* __KERNEL__ */
 378
 379 #endif /* _ASM_MICROBLAZE_UACCESS_H */