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 extern long __user_bad(void);
 150
 151 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 152 ({                                                              \
 153         __asm__ __volatile__ (                                  \
 154                         "1:"    insn    " %1, %2, r0;"          \
 155                         "       addk    %0, r0, r0;"            \
 156                         "2:                     "               \
 157                         __FIXUP_SECTION                         \
 158                         "3:     brid    2b;"                    \
 159                         "       addik   %0, r0, %3;"            \
 160                         ".previous;"                            \
 161                         __EX_TABLE_SECTION                      \
 162                         ".word  1b,3b;"                         \
 163                         ".previous;"                            \
 164                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 165                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 166         );                                                      \
 167 })
 168
 169 /**
 170  * get_user: - Get a simple variable from user space.
 171  * @x:   Variable to store result.
 172  * @ptr: Source address, in user space.
 173  *
 174  * Context: User context only.  This function may sleep.
 175  *
 176  * This macro copies a single simple variable from user space to kernel
 177  * space.  It supports simple types like char and int, but not larger
 178  * data types like structures or arrays.
 179  *
 180  * @ptr must have pointer-to-simple-variable type, and the result of
 181  * dereferencing @ptr must be assignable to @x without a cast.
 182  *
 183  * Returns zero on success, or -EFAULT on error.
 184  * On error, the variable @x is set to zero.
 185  */
 186
 187 #define __get_user(x, ptr)                                              \
 188 ({                                                                      \
 189         unsigned long __gu_val;                                         \
 190         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 191         long __gu_err;                                                  \
 192         switch (sizeof(*(ptr))) {                                       \
 193         case 1:                                                         \
 194                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 195                 break;                                                  \
 196         case 2:                                                         \
 197                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 198                 break;                                                  \
 199         case 4:                                                         \
 200                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 201                 break;                                                  \
 202         default:                                                        \
 203                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 204         }                                                               \
 205         x = (__typeof__(*(ptr))) __gu_val;                              \
 206         __gu_err;                                                       \
 207 })
 208
 209
 210 #define get_user(x, ptr)                                                \
 211 ({                                                                      \
 212         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
 213                 ? __get_user((x), (ptr)) : -EFAULT;                     \
 214 })
 215
 216 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 217 ({                                                              \
 218         __asm__ __volatile__ (                                  \
 219                         "1:"    insn    " %1, %2, r0;"          \
 220                         "       addk    %0, r0, r0;"            \
 221                         "2:                     "               \
 222                         __FIXUP_SECTION                         \
 223                         "3:     brid    2b;"                    \
 224                         "       addik   %0, r0, %3;"            \
 225                         ".previous;"                            \
 226                         __EX_TABLE_SECTION                      \
 227                         ".word  1b,3b;"                         \
 228                         ".previous;"                            \
 229                 : "=&r"(__gu_err)                               \
 230                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 231         );                                                      \
 232 })
 233
 234 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 235 ({                                                              \
 236         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 237                         "1:     swi     %0, %2, 0;"             \
 238                         "       lwi     %0, %1, 4;"             \
 239                         "2:     swi     %0, %2, 4;"             \
 240                         "       addk    %0, r0, r0;"            \
 241                         "3:                     "               \
 242                         __FIXUP_SECTION                         \
 243                         "4:     brid    3b;"                    \
 244                         "       addik   %0, r0, %3;"            \
 245                         ".previous;"                            \
 246                         __EX_TABLE_SECTION                      \
 247                         ".word  1b,4b,2b,4b;"                   \
 248                         ".previous;"                            \
 249                 : "=&r"(__gu_err)                               \
 250                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 251                 );                                              \
 252 })
 253
 254 #define __put_user(x, ptr)                                              \
 255 ({                                                                      \
 256         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 257         long __gu_err = 0;                                              \
 258         switch (sizeof(__gu_val)) {                                     \
 259         case 1:                                                         \
 260                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 261                 break;                                                  \
 262         case 2:                                                         \
 263                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 264                 break;                                                  \
 265         case 4:                                                         \
 266                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 267                 break;                                                  \
 268         case 8:                                                         \
 269                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 270                 break;                                                  \
 271         default:                                                        \
 272                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 273         }                                                               \
 274         __gu_err;                                                       \
 275 })
 276
 277 #define put_user(x, ptr)        __put_user((x), (ptr))
 278
 279 #define copy_to_user(to, from, n)       (memcpy((to), (from), (n)), 0)
 280 #define copy_from_user(to, from, n)     (memcpy((to), (from), (n)), 0)
 281
 282 #define __copy_to_user(to, from, n)     (copy_to_user((to), (from), (n)))
 283 #define __copy_from_user(to, from, n)   (copy_from_user((to), (from), (n)))
 284 #define __copy_to_user_inatomic(to, from, n) \
 285                         (__copy_to_user((to), (from), (n)))
 286 #define __copy_from_user_inatomic(to, from, n) \
 287                         (__copy_from_user((to), (from), (n)))
 288
 289 extern long strncpy_from_user(char *dst, const char *src, long count);
 290 extern long strnlen_user(const char *src, long count);
 291
 292 #else /* CONFIG_MMU */
 293
 294 /* put_user and get_user macros */
 295
 296 extern long __user_bad(void);
 297
 298 #define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 299 ({                                                              \
 300         __asm__ __volatile__ (                                  \
 301                         "1:"    insn    " %1, %2, r0;"          \
 302                         "       addk    %0, r0, r0;"            \
 303                         "2:                     "               \
 304                         __FIXUP_SECTION                         \
 305                         "3:     brid    2b;     "               \
 306                         "       addik   %0, r0, %3;"            \
 307                         ".previous;"                            \
 308                         __EX_TABLE_SECTION                      \
 309                         ".word  1b,3b;"                         \
 310                         ".previous;"                            \
 311                 : "=&r"(__gu_err), "=r"(__gu_val)               \
 312                 : "r"(__gu_ptr), "i"(-EFAULT)                   \
 313         );                                                      \
 314 })
 315
 316 #define __get_user(x, ptr)                                              \
 317 ({                                                                      \
 318         unsigned long __gu_val;                                         \
 319         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 320         long __gu_err;                                                  \
 321         switch (sizeof(*(ptr))) {                                       \
 322         case 1:                                                         \
 323                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 324                 break;                                                  \
 325         case 2:                                                         \
 326                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 327                 break;                                                  \
 328         case 4:                                                         \
 329                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 330                 break;                                                  \
 331         default:                                                        \
 332                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 333         }                                                               \
 334         x = (__typeof__(*(ptr))) __gu_val;                              \
 335         __gu_err;                                                       \
 336 })
 337
 338 /**
 339  * get_user: - Get a simple variable from user space.
 340  * @x:   Variable to store result.
 341  * @ptr: Source address, in user space.
 342  *
 343  * Context: User context only.  This function may sleep.
 344  *
 345  * This macro copies a single simple variable from user space to kernel
 346  * space.  It supports simple types like char and int, but not larger
 347  * data types like structures or arrays.
 348  *
 349  * @ptr must have pointer-to-simple-variable type, and the result of
 350  * dereferencing @ptr must be assignable to @x without a cast.
 351  *
 352  * Returns zero on success, or -EFAULT on error.
 353  * On error, the variable @x is set to zero.
 354  */
 355
 356 #define get_user(x, ptr)                                                \
 357 ({                                                                      \
 358         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
 359                 ? __get_user((x), (ptr)) : -EFAULT;                     \
 360 })
 361
 362 /**
 363  * put_user: - Write a simple value into user space.
 364  * @x:   Value to copy to user space.
 365  * @ptr: Destination address, in user space.
 366  *
 367  * Context: User context only.  This function may sleep.
 368  *
 369  * This macro copies a single simple value from kernel space to user
 370  * space.  It supports simple types like char and int, but not larger
 371  * data types like structures or arrays.
 372  *
 373  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 374  * to the result of dereferencing @ptr.
 375  *
 376  * Returns zero on success, or -EFAULT on error.
 377  */
 378
 379 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 380 ({                                                              \
 381         __asm__ __volatile__ (                                  \
 382                         "1:"    insn    " %1, %2, r0;"          \
 383                         "       addk    %0, r0, r0;"            \
 384                         "2:                     "               \
 385                         __FIXUP_SECTION                         \
 386                         "3:     brid    2b;"                    \
 387                         "       addik   %0, r0, %3;"            \
 388                         ".previous;"                            \
 389                         __EX_TABLE_SECTION                      \
 390                         ".word  1b,3b;"                         \
 391                         ".previous;"                            \
 392                 : "=&r"(__gu_err)                               \
 393                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 394         );                                                      \
 395 })
 396
 397 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 398 ({                                                              \
 399         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 400                         "1:     swi     %0, %2, 0;"             \
 401                         "       lwi     %0, %1, 4;"             \
 402                         "2:     swi     %0, %2, 4;"             \
 403                         "       addk    %0, r0, r0;"            \
 404                         "3:                             "       \
 405                         __FIXUP_SECTION                         \
 406                         "4:     brid    3b;"                    \
 407                         "       addik   %0, r0, %3;"            \
 408                         ".previous;"                            \
 409                         __EX_TABLE_SECTION                      \
 410                         ".word  1b,4b,2b,4b;"                   \
 411                         ".previous;"                            \
 412                 : "=&r"(__gu_err)                               \
 413                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 414                 );                                              \
 415 })
 416
 417 #define __put_user(x, ptr)                                              \
 418 ({                                                                      \
 419         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 420         long __gu_err = 0;                                              \
 421         switch (sizeof(__gu_val)) {                                     \
 422         case 1:                                                         \
 423                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 424                 break;                                                  \
 425         case 2:                                                         \
 426                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 427                 break;                                                  \
 428         case 4:                                                         \
 429                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 430                 break;                                                  \
 431         case 8:                                                         \
 432                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 433                 break;                                                  \
 434         default:                                                        \
 435                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 436         }                                                               \
 437         __gu_err;                                                       \
 438 })
 439
 440 #define put_user(x, ptr)                                                \
 441 ({                                                                      \
 442         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
 443                 ? __put_user((x), (ptr)) : -EFAULT;                     \
 444 })
 445
 446 #define __copy_from_user(to, from, n)   \
 447         __copy_tofrom_user((__force void __user *)(to), \
 448                                 (void __user *)(from), (n))
 449 #define __copy_from_user_inatomic(to, from, n) \
 450                 copy_from_user((to), (from), (n))
 451
 452 static inline long copy_from_user(void *to,
 453                 const void __user *from, unsigned long n)
 454 {
 455         might_sleep();
 456         if (access_ok(VERIFY_READ, from, n))
 457                 return __copy_from_user(to, from, n);
 458         else
 459                 return n;
 460 }
 461
 462 #define __copy_to_user(to, from, n)     \
 463                 __copy_tofrom_user((void __user *)(to), \
 464                         (__force const void __user *)(from), (n))
 465 #define __copy_to_user_inatomic(to, from, n)    copy_to_user((to), (from), (n))
 466
 467 static inline long copy_to_user(void __user *to,
 468                 const void *from, unsigned long n)
 469 {
 470         might_sleep();
 471         if (access_ok(VERIFY_WRITE, to, n))
 472                 return __copy_to_user(to, from, n);
 473         else
 474                 return n;
 475 }
 476
 477 extern int __strncpy_user(char *to, const char __user *from, int len);
 478
 479 #define __strncpy_from_user     __strncpy_user
 480
 481 static inline long
 482 strncpy_from_user(char *dst, const char __user *src, long count)
 483 {
 484         if (!access_ok(VERIFY_READ, src, 1))
 485                 return -EFAULT;
 486         return __strncpy_from_user(dst, src, count);
 487 }
 488
 489 extern int __strnlen_user(const char __user *sstr, int len);
 490
 491 #define strnlen_user(str, len)  \
 492                 (access_ok(VERIFY_READ, str, 1) ? __strnlen_user(str, len) : 0)
 493
 494 #endif /* CONFIG_MMU */
 495
 496 #endif  /* __ASSEMBLY__ */
 497 #endif /* __KERNEL__ */
 498
 499 #endif /* _ASM_MICROBLAZE_UACCESS_H */