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, %1, r0;"    \
 124                         "       addik   %0, %0, -1;"    \
 125                         "       bneid   %0, 1b;"        \
 126                         "       addik   %1, %1, 1;"     \
 127                         "2:                     "       \
 128                         __EX_TABLE_SECTION              \
 129                         ".word  1b,2b;"                 \
 130                         ".previous;"                    \
 131                 : "=r"(n), "=r"(to)                     \
 132                 : "0"(n), "1"(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 /* put_user and get_user macros */
 148 extern long __user_bad(void);
 149
 150 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 151 ({                                                              \
 152         __asm__ __volatile__ (                                  \
 153                         "1:"    insn    " %1, %2, r0;"          \
 154                         "       addk    %0, r0, r0;"            \
 155                         "2:                     "               \
 156                         __FIXUP_SECTION                         \
 157                         "3:     brid    2b;"                    \
 158                         "       addik   %0, r0, %3;"            \
 159                         ".previous;"                            \
 160                         __EX_TABLE_SECTION                      \
 161                         ".word  1b,3b;"                         \
 162                         ".previous;"                            \
 163                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 164                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 165         );                                                      \
 166 })
 167
 168 /**
 169  * get_user: - Get a simple variable from user space.
 170  * @x:   Variable to store result.
 171  * @ptr: Source address, in user space.
 172  *
 173  * Context: User context only.  This function may sleep.
 174  *
 175  * This macro copies a single simple variable from user space to kernel
 176  * space.  It supports simple types like char and int, but not larger
 177  * data types like structures or arrays.
 178  *
 179  * @ptr must have pointer-to-simple-variable type, and the result of
 180  * dereferencing @ptr must be assignable to @x without a cast.
 181  *
 182  * Returns zero on success, or -EFAULT on error.
 183  * On error, the variable @x is set to zero.
 184  */
 185 #define get_user(x, ptr)                                                \
 186         __get_user_check((x), (ptr), sizeof(*(ptr)))
 187
 188 #define __get_user_check(x, ptr, size)                                  \
 189 ({                                                                      \
 190         unsigned long __gu_val = 0;                                     \
 191         const typeof(*(ptr)) __user *__gu_addr = (ptr);                 \
 192         int __gu_err = 0;                                               \
 193                                                                         \
 194         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 195                 switch (size) {                                         \
 196                 case 1:                                                 \
 197                         __get_user_asm("lbu", __gu_addr, __gu_val,      \
 198                                        __gu_err);                       \
 199                         break;                                          \
 200                 case 2:                                                 \
 201                         __get_user_asm("lhu", __gu_addr, __gu_val,      \
 202                                        __gu_err);                       \
 203                         break;                                          \
 204                 case 4:                                                 \
 205                         __get_user_asm("lw", __gu_addr, __gu_val,       \
 206                                        __gu_err);                       \
 207                         break;                                          \
 208                 default:                                                \
 209                         __gu_err = __user_bad();                        \
 210                         break;                                          \
 211                 }                                                       \
 212         } else {                                                        \
 213                 __gu_err = -EFAULT;                                     \
 214         }                                                               \
 215         x = (typeof(*(ptr)))__gu_val;                                   \
 216         __gu_err;                                                       \
 217 })
 218
 219 #define __get_user(x, ptr)                                              \
 220 ({                                                                      \
 221         unsigned long __gu_val;                                         \
 222         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 223         long __gu_err;                                                  \
 224         switch (sizeof(*(ptr))) {                                       \
 225         case 1:                                                         \
 226                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 227                 break;                                                  \
 228         case 2:                                                         \
 229                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 230                 break;                                                  \
 231         case 4:                                                         \
 232                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 233                 break;                                                  \
 234         default:                                                        \
 235                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 236         }                                                               \
 237         x = (__typeof__(*(ptr))) __gu_val;                              \
 238         __gu_err;                                                       \
 239 })
 240
 241
 242 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 243 ({                                                              \
 244         __asm__ __volatile__ (                                  \
 245                         "1:"    insn    " %1, %2, r0;"          \
 246                         "       addk    %0, r0, r0;"            \
 247                         "2:                     "               \
 248                         __FIXUP_SECTION                         \
 249                         "3:     brid    2b;"                    \
 250                         "       addik   %0, r0, %3;"            \
 251                         ".previous;"                            \
 252                         __EX_TABLE_SECTION                      \
 253                         ".word  1b,3b;"                         \
 254                         ".previous;"                            \
 255                 : "=&r"(__gu_err)                               \
 256                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 257         );                                                      \
 258 })
 259
 260 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 261 ({                                                              \
 262         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 263                         "1:     swi     %0, %2, 0;"             \
 264                         "       lwi     %0, %1, 4;"             \
 265                         "2:     swi     %0, %2, 4;"             \
 266                         "       addk    %0, r0, r0;"            \
 267                         "3:                     "               \
 268                         __FIXUP_SECTION                         \
 269                         "4:     brid    3b;"                    \
 270                         "       addik   %0, r0, %3;"            \
 271                         ".previous;"                            \
 272                         __EX_TABLE_SECTION                      \
 273                         ".word  1b,4b,2b,4b;"                   \
 274                         ".previous;"                            \
 275                 : "=&r"(__gu_err)                               \
 276                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 277                 );                                              \
 278 })
 279
 280 /**
 281  * put_user: - Write a simple value into user space.
 282  * @x:   Value to copy to user space.
 283  * @ptr: Destination address, in user space.
 284  *
 285  * Context: User context only.  This function may sleep.
 286  *
 287  * This macro copies a single simple value from kernel space to user
 288  * space.  It supports simple types like char and int, but not larger
 289  * data types like structures or arrays.
 290  *
 291  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 292  * to the result of dereferencing @ptr.
 293  *
 294  * Returns zero on success, or -EFAULT on error.
 295  */
 296 #define put_user(x, ptr)                                                \
 297         __put_user_check((x), (ptr), sizeof(*(ptr)))
 298
 299 #define __put_user_check(x, ptr, size)                                  \
 300 ({                                                                      \
 301         typeof(*(ptr)) __pu_val;                                        \
 302         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 303         int __pu_err = 0;                                               \
 304                                                                         \
 305         __pu_val = (x);                                                 \
 306         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 307                 switch (size) {                                         \
 308                 case 1:                                                 \
 309                         __put_user_asm("sb", __pu_addr, __pu_val,       \
 310                                        __pu_err);                       \
 311                         break;                                          \
 312                 case 2:                                                 \
 313                         __put_user_asm("sh", __pu_addr, __pu_val,       \
 314                                        __pu_err);                       \
 315                         break;                                          \
 316                 case 4:                                                 \
 317                         __put_user_asm("sw", __pu_addr, __pu_val,       \
 318                                        __pu_err);                       \
 319                         break;                                          \
 320                 case 8:                                                 \
 321                         __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
 322                         break;                                          \
 323                 default:                                                \
 324                         __pu_err = __user_bad();                        \
 325                         break;                                          \
 326                 }                                                       \
 327         } else {                                                        \
 328                 __pu_err = -EFAULT;                                     \
 329         }                                                               \
 330         __pu_err;                                                       \
 331 })
 332
 333 #define __put_user(x, ptr)                                              \
 334 ({                                                                      \
 335         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 336         long __gu_err = 0;                                              \
 337         switch (sizeof(__gu_val)) {                                     \
 338         case 1:                                                         \
 339                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 340                 break;                                                  \
 341         case 2:                                                         \
 342                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 343                 break;                                                  \
 344         case 4:                                                         \
 345                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 346                 break;                                                  \
 347         case 8:                                                         \
 348                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 349                 break;                                                  \
 350         default:                                                        \
 351                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 352         }                                                               \
 353         __gu_err;                                                       \
 354 })
 355
 356
 357 /* copy_to_from_user */
 358 #define __copy_from_user(to, from, n)   \
 359         __copy_tofrom_user((__force void __user *)(to), \
 360                                 (void __user *)(from), (n))
 361 #define __copy_from_user_inatomic(to, from, n) \
 362                 __copy_from_user((to), (from), (n))
 363
 364 static inline long copy_from_user(void *to,
 365                 const void __user *from, unsigned long n)
 366 {
 367         unsigned long res = n;
 368         might_sleep();
 369         if (likely(access_ok(VERIFY_READ, from, n)))
 370                 res = __copy_from_user(to, from, n);
 371         if (unlikely(res))
 372                 memset(to + (n - res), 0, res);
 373         return res;
 374 }
 375
 376 #define __copy_to_user(to, from, n)     \
 377                 __copy_tofrom_user((void __user *)(to), \
 378                         (__force const void __user *)(from), (n))
 379 #define __copy_to_user_inatomic(to, from, n) __copy_to_user((to), (from), (n))
 380
 381 static inline long copy_to_user(void __user *to,
 382                 const void *from, unsigned long n)
 383 {
 384         might_sleep();
 385         if (access_ok(VERIFY_WRITE, to, n))
 386                 return __copy_to_user(to, from, n);
 387         return n;
 388 }
 389
 390 /*
 391  * Copy a null terminated string from userspace.
 392  */
 393 extern int __strncpy_user(char *to, const char __user *from, int len);
 394
 395 #define __strncpy_from_user     __strncpy_user
 396
 397 static inline long
 398 strncpy_from_user(char *dst, const char __user *src, long count)
 399 {
 400         if (!access_ok(VERIFY_READ, src, 1))
 401                 return -EFAULT;
 402         return __strncpy_from_user(dst, src, count);
 403 }
 404
 405 /*
 406  * Return the size of a string (including the ending 0)
 407  *
 408  * Return 0 on exception, a value greater than N if too long
 409  */
 410 extern int __strnlen_user(const char __user *sstr, int len);
 411
 412 static inline long strnlen_user(const char __user *src, long n)
 413 {
 414         if (!access_ok(VERIFY_READ, src, 1))
 415                 return 0;
 416         return __strnlen_user(src, n);
 417 }
 418
 419 #endif  /* __ASSEMBLY__ */
 420 #endif /* __KERNEL__ */
 421
 422 #endif /* _ASM_MICROBLAZE_UACCESS_H */