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 /* 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
 186 #define __get_user(x, ptr)                                              \
 187 ({                                                                      \
 188         unsigned long __gu_val;                                         \
 189         /*unsigned long __gu_ptr = (unsigned long)(ptr);*/              \
 190         long __gu_err;                                                  \
 191         switch (sizeof(*(ptr))) {                                       \
 192         case 1:                                                         \
 193                 __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 194                 break;                                                  \
 195         case 2:                                                         \
 196                 __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 197                 break;                                                  \
 198         case 4:                                                         \
 199                 __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 200                 break;                                                  \
 201         default:                                                        \
 202                 /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 203         }                                                               \
 204         x = (__typeof__(*(ptr))) __gu_val;                              \
 205         __gu_err;                                                       \
 206 })
 207
 208
 209 #define get_user(x, ptr)                                                \
 210 ({                                                                      \
 211         access_ok(VERIFY_READ, (ptr), sizeof(*(ptr)))                   \
 212                 ? __get_user((x), (ptr)) : -EFAULT;                     \
 213 })
 214
 215 #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 216 ({                                                              \
 217         __asm__ __volatile__ (                                  \
 218                         "1:"    insn    " %1, %2, r0;"          \
 219                         "       addk    %0, r0, r0;"            \
 220                         "2:                     "               \
 221                         __FIXUP_SECTION                         \
 222                         "3:     brid    2b;"                    \
 223                         "       addik   %0, r0, %3;"            \
 224                         ".previous;"                            \
 225                         __EX_TABLE_SECTION                      \
 226                         ".word  1b,3b;"                         \
 227                         ".previous;"                            \
 228                 : "=&r"(__gu_err)                               \
 229                 : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 230         );                                                      \
 231 })
 232
 233 #define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 234 ({                                                              \
 235         __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 236                         "1:     swi     %0, %2, 0;"             \
 237                         "       lwi     %0, %1, 4;"             \
 238                         "2:     swi     %0, %2, 4;"             \
 239                         "       addk    %0, r0, r0;"            \
 240                         "3:                     "               \
 241                         __FIXUP_SECTION                         \
 242                         "4:     brid    3b;"                    \
 243                         "       addik   %0, r0, %3;"            \
 244                         ".previous;"                            \
 245                         __EX_TABLE_SECTION                      \
 246                         ".word  1b,4b,2b,4b;"                   \
 247                         ".previous;"                            \
 248                 : "=&r"(__gu_err)                               \
 249                 : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 250                 );                                              \
 251 })
 252
 253 /**
 254  * put_user: - Write a simple value into user space.
 255  * @x:   Value to copy to user space.
 256  * @ptr: Destination address, in user space.
 257  *
 258  * Context: User context only.  This function may sleep.
 259  *
 260  * This macro copies a single simple value from kernel space to user
 261  * space.  It supports simple types like char and int, but not larger
 262  * data types like structures or arrays.
 263  *
 264  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 265  * to the result of dereferencing @ptr.
 266  *
 267  * Returns zero on success, or -EFAULT on error.
 268  */
 269
 270 #define __put_user(x, ptr)                                              \
 271 ({                                                                      \
 272         __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 273         long __gu_err = 0;                                              \
 274         switch (sizeof(__gu_val)) {                                     \
 275         case 1:                                                         \
 276                 __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 277                 break;                                                  \
 278         case 2:                                                         \
 279                 __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 280                 break;                                                  \
 281         case 4:                                                         \
 282                 __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 283                 break;                                                  \
 284         case 8:                                                         \
 285                 __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 286                 break;                                                  \
 287         default:                                                        \
 288                 /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 289         }                                                               \
 290         __gu_err;                                                       \
 291 })
 292
 293 #ifndef CONFIG_MMU
 294
 295 #define put_user(x, ptr)        __put_user((x), (ptr))
 296
 297 #else /* CONFIG_MMU */
 298
 299 #define put_user(x, ptr)                                                \
 300 ({                                                                      \
 301         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr)))                  \
 302                 ? __put_user((x), (ptr)) : -EFAULT;                     \
 303 })
 304 #endif /* CONFIG_MMU */
 305
 306 /* copy_to_from_user */
 307 #define __copy_from_user(to, from, n)   \
 308         __copy_tofrom_user((__force void __user *)(to), \
 309                                 (void __user *)(from), (n))
 310 #define __copy_from_user_inatomic(to, from, n) \
 311                 copy_from_user((to), (from), (n))
 312
 313 static inline long copy_from_user(void *to,
 314                 const void __user *from, unsigned long n)
 315 {
 316         might_sleep();
 317         if (access_ok(VERIFY_READ, from, n))
 318                 return __copy_from_user(to, from, n);
 319         return n;
 320 }
 321
 322 #define __copy_to_user(to, from, n)     \
 323                 __copy_tofrom_user((void __user *)(to), \
 324                         (__force const void __user *)(from), (n))
 325 #define __copy_to_user_inatomic(to, from, n)    copy_to_user((to), (from), (n))
 326
 327 static inline long copy_to_user(void __user *to,
 328                 const void *from, unsigned long n)
 329 {
 330         might_sleep();
 331         if (access_ok(VERIFY_WRITE, to, n))
 332                 return __copy_to_user(to, from, n);
 333         return n;
 334 }
 335
 336 /*
 337  * Copy a null terminated string from userspace.
 338  */
 339 extern int __strncpy_user(char *to, const char __user *from, int len);
 340
 341 #define __strncpy_from_user     __strncpy_user
 342
 343 static inline long
 344 strncpy_from_user(char *dst, const char __user *src, long count)
 345 {
 346         if (!access_ok(VERIFY_READ, src, 1))
 347                 return -EFAULT;
 348         return __strncpy_from_user(dst, src, count);
 349 }
 350
 351 /*
 352  * Return the size of a string (including the ending 0)
 353  *
 354  * Return 0 on exception, a value greater than N if too long
 355  */
 356 extern int __strnlen_user(const char __user *sstr, int len);
 357
 358 static inline long strnlen_user(const char __user *src, long n)
 359 {
 360         if (!access_ok(VERIFY_READ, src, 1))
 361                 return 0;
 362         return __strnlen_user(src, n);
 363 }
 364
 365 #endif  /* __ASSEMBLY__ */
 366 #endif /* __KERNEL__ */
 367
 368 #endif /* _ASM_MICROBLAZE_UACCESS_H */