arch/avr32/include/asm/uaccess.h

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #ifndef __ASM_AVR32_UACCESS_H
   9 #define __ASM_AVR32_UACCESS_H
  10
  11 #include <linux/errno.h>
  12 #include <linux/sched.h>
  13
  14 #define VERIFY_READ     0
  15 #define VERIFY_WRITE    1
  16
  17 typedef struct {
  18         unsigned int is_user_space;
  19 } mm_segment_t;
  20
  21 /*
  22  * The fs value determines whether argument validity checking should be
  23  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  24  * get_fs() == KERNEL_DS, checking is bypassed.
  25  *
  26  * For historical reasons (Data Segment Register?), these macros are misnamed.
  27  */
  28 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  29 #define segment_eq(a, b)        ((a).is_user_space == (b).is_user_space)
  30
  31 #define USER_ADDR_LIMIT 0x80000000
  32
  33 #define KERNEL_DS       MAKE_MM_SEG(0)
  34 #define USER_DS         MAKE_MM_SEG(1)
  35
  36 #define get_ds()        (KERNEL_DS)
  37
  38 static inline mm_segment_t get_fs(void)
  39 {
  40         return MAKE_MM_SEG(test_thread_flag(TIF_USERSPACE));
  41 }
  42
  43 static inline void set_fs(mm_segment_t s)
  44 {
  45         if (s.is_user_space)
  46                 set_thread_flag(TIF_USERSPACE);
  47         else
  48                 clear_thread_flag(TIF_USERSPACE);
  49 }
  50
  51 /*
  52  * Test whether a block of memory is a valid user space address.
  53  * Returns 0 if the range is valid, nonzero otherwise.
  54  *
  55  * We do the following checks:
  56  *   1. Is the access from kernel space?
  57  *   2. Does (addr + size) set the carry bit?
  58  *   3. Is (addr + size) a negative number (i.e. >= 0x80000000)?
  59  *
  60  * If yes on the first check, access is granted.
  61  * If no on any of the others, access is denied.
  62  */
  63 #define __range_ok(addr, size)                                          \
  64         (test_thread_flag(TIF_USERSPACE)                                \
  65          && (((unsigned long)(addr) >= 0x80000000)                      \
  66              || ((unsigned long)(size) > 0x80000000)                    \
  67              || (((unsigned long)(addr) + (unsigned long)(size)) > 0x80000000)))
  68
  69 #define access_ok(type, addr, size) (likely(__range_ok(addr, size) == 0))
  70
  71 /* Generic arbitrary sized copy. Return the number of bytes NOT copied */
  72 extern __kernel_size_t __copy_user(void *to, const void *from,
  73                                    __kernel_size_t n);
  74
  75 extern __kernel_size_t copy_to_user(void __user *to, const void *from,
  76                                     __kernel_size_t n);
  77 extern __kernel_size_t copy_from_user(void *to, const void __user *from,
  78                                       __kernel_size_t n);
  79
  80 static inline __kernel_size_t __copy_to_user(void __user *to, const void *from,
  81                                              __kernel_size_t n)
  82 {
  83         return __copy_user((void __force *)to, from, n);
  84 }
  85 static inline __kernel_size_t __copy_from_user(void *to,
  86                                                const void __user *from,
  87                                                __kernel_size_t n)
  88 {
  89         return __copy_user(to, (const void __force *)from, n);
  90 }
  91
  92 #define __copy_to_user_inatomic __copy_to_user
  93 #define __copy_from_user_inatomic __copy_from_user
  94
  95 /*
  96  * put_user: - Write a simple value into user space.
  97  * @x:   Value to copy to user space.
  98  * @ptr: Destination address, in user space.
  99  *
 100  * Context: User context only. This function may sleep if pagefaults are
 101  *          enabled.
 102  *
 103  * This macro copies a single simple value from kernel space to user
 104  * space.  It supports simple types like char and int, but not larger
 105  * data types like structures or arrays.
 106  *
 107  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 108  * to the result of dereferencing @ptr.
 109  *
 110  * Returns zero on success, or -EFAULT on error.
 111  */
 112 #define put_user(x, ptr)        \
 113         __put_user_check((x), (ptr), sizeof(*(ptr)))
 114
 115 /*
 116  * get_user: - Get a simple variable from user space.
 117  * @x:   Variable to store result.
 118  * @ptr: Source address, in user space.
 119  *
 120  * Context: User context only. This function may sleep if pagefaults are
 121  *          enabled.
 122  *
 123  * This macro copies a single simple variable from user space to kernel
 124  * space.  It supports simple types like char and int, but not larger
 125  * data types like structures or arrays.
 126  *
 127  * @ptr must have pointer-to-simple-variable type, and the result of
 128  * dereferencing @ptr must be assignable to @x without a cast.
 129  *
 130  * Returns zero on success, or -EFAULT on error.
 131  * On error, the variable @x is set to zero.
 132  */
 133 #define get_user(x, ptr) \
 134         __get_user_check((x), (ptr), sizeof(*(ptr)))
 135
 136 /*
 137  * __put_user: - Write a simple value into user space, with less checking.
 138  * @x:   Value to copy to user space.
 139  * @ptr: Destination address, in user space.
 140  *
 141  * Context: User context only. This function may sleep if pagefaults are
 142  *          enabled.
 143  *
 144  * This macro copies a single simple value from kernel space to user
 145  * space.  It supports simple types like char and int, but not larger
 146  * data types like structures or arrays.
 147  *
 148  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 149  * to the result of dereferencing @ptr.
 150  *
 151  * Caller must check the pointer with access_ok() before calling this
 152  * function.
 153  *
 154  * Returns zero on success, or -EFAULT on error.
 155  */
 156 #define __put_user(x, ptr) \
 157         __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 158
 159 /*
 160  * __get_user: - Get a simple variable from user space, with less checking.
 161  * @x:   Variable to store result.
 162  * @ptr: Source address, in user space.
 163  *
 164  * Context: User context only. This function may sleep if pagefaults are
 165  *          enabled.
 166  *
 167  * This macro copies a single simple variable from user space to kernel
 168  * space.  It supports simple types like char and int, but not larger
 169  * data types like structures or arrays.
 170  *
 171  * @ptr must have pointer-to-simple-variable type, and the result of
 172  * dereferencing @ptr must be assignable to @x without a cast.
 173  *
 174  * Caller must check the pointer with access_ok() before calling this
 175  * function.
 176  *
 177  * Returns zero on success, or -EFAULT on error.
 178  * On error, the variable @x is set to zero.
 179  */
 180 #define __get_user(x, ptr) \
 181         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 182
 183 extern int __get_user_bad(void);
 184 extern int __put_user_bad(void);
 185
 186 #define __get_user_nocheck(x, ptr, size)                                \
 187 ({                                                                      \
 188         unsigned long __gu_val = 0;                                     \
 189         int __gu_err = 0;                                               \
 190                                                                         \
 191         switch (size) {                                                 \
 192         case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break;   \
 193         case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break;   \
 194         case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break;    \
 195         default: __gu_err = __get_user_bad(); break;                    \
 196         }                                                               \
 197                                                                         \
 198         x = (__force typeof(*(ptr)))__gu_val;                           \
 199         __gu_err;                                                       \
 200 })
 201
 202 #define __get_user_check(x, ptr, size)                                  \
 203 ({                                                                      \
 204         unsigned long __gu_val = 0;                                     \
 205         const typeof(*(ptr)) __user * __gu_addr = (ptr);                \
 206         int __gu_err = 0;                                               \
 207                                                                         \
 208         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 209                 switch (size) {                                         \
 210                 case 1:                                                 \
 211                         __get_user_asm("ub", __gu_val, __gu_addr,       \
 212                                        __gu_err);                       \
 213                         break;                                          \
 214                 case 2:                                                 \
 215                         __get_user_asm("uh", __gu_val, __gu_addr,       \
 216                                        __gu_err);                       \
 217                         break;                                          \
 218                 case 4:                                                 \
 219                         __get_user_asm("w", __gu_val, __gu_addr,        \
 220                                        __gu_err);                       \
 221                         break;                                          \
 222                 default:                                                \
 223                         __gu_err = __get_user_bad();                    \
 224                         break;                                          \
 225                 }                                                       \
 226         } else {                                                        \
 227                 __gu_err = -EFAULT;                                     \
 228         }                                                               \
 229         x = (__force typeof(*(ptr)))__gu_val;                           \
 230         __gu_err;                                                       \
 231 })
 232
 233 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err)                 \
 234         asm volatile(                                                   \
 235                 "1:     ld." suffix "   %1, %3                  \n"     \
 236                 "2:                                             \n"     \
 237                 "       .subsection 1                           \n"     \
 238                 "3:     mov     %0, %4                          \n"     \
 239                 "       rjmp    2b                              \n"     \
 240                 "       .subsection 0                           \n"     \
 241                 "       .section __ex_table, \"a\"              \n"     \
 242                 "       .long   1b, 3b                          \n"     \
 243                 "       .previous                               \n"     \
 244                 : "=r"(__gu_err), "=r"(__gu_val)                        \
 245                 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
 246
 247 #define __put_user_nocheck(x, ptr, size)                                \
 248 ({                                                                      \
 249         typeof(*(ptr)) __pu_val;                                        \
 250         int __pu_err = 0;                                               \
 251                                                                         \
 252         __pu_val = (x);                                                 \
 253         switch (size) {                                                 \
 254         case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break;    \
 255         case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break;    \
 256         case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break;    \
 257         case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break;    \
 258         default: __pu_err = __put_user_bad(); break;                    \
 259         }                                                               \
 260         __pu_err;                                                       \
 261 })
 262
 263 #define __put_user_check(x, ptr, size)                                  \
 264 ({                                                                      \
 265         typeof(*(ptr)) __pu_val;                                        \
 266         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 267         int __pu_err = 0;                                               \
 268                                                                         \
 269         __pu_val = (x);                                                 \
 270         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 271                 switch (size) {                                         \
 272                 case 1:                                                 \
 273                         __put_user_asm("b", __pu_addr, __pu_val,        \
 274                                        __pu_err);                       \
 275                         break;                                          \
 276                 case 2:                                                 \
 277                         __put_user_asm("h", __pu_addr, __pu_val,        \
 278                                        __pu_err);                       \
 279                         break;                                          \
 280                 case 4:                                                 \
 281                         __put_user_asm("w", __pu_addr, __pu_val,        \
 282                                        __pu_err);                       \
 283                         break;                                          \
 284                 case 8:                                                 \
 285                         __put_user_asm("d", __pu_addr, __pu_val,        \
 286                                        __pu_err);                       \
 287                         break;                                          \
 288                 default:                                                \
 289                         __pu_err = __put_user_bad();                    \
 290                         break;                                          \
 291                 }                                                       \
 292         } else {                                                        \
 293                 __pu_err = -EFAULT;                                     \
 294         }                                                               \
 295         __pu_err;                                                       \
 296 })
 297
 298 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err)                 \
 299         asm volatile(                                                   \
 300                 "1:     st." suffix "   %1, %3                  \n"     \
 301                 "2:                                             \n"     \
 302                 "       .subsection 1                           \n"     \
 303                 "3:     mov     %0, %4                          \n"     \
 304                 "       rjmp    2b                              \n"     \
 305                 "       .subsection 0                           \n"     \
 306                 "       .section __ex_table, \"a\"              \n"     \
 307                 "       .long   1b, 3b                          \n"     \
 308                 "       .previous                               \n"     \
 309                 : "=r"(__gu_err), "=m"(*(ptr))                          \
 310                 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
 311
 312 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
 313 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
 314
 315 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 316 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 317
 318 extern long strnlen_user(const char __user *__s, long __n);
 319 extern long __strnlen_user(const char __user *__s, long __n);
 320
 321 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
 322
 323 struct exception_table_entry
 324 {
 325         unsigned long insn, fixup;
 326 };
 327
 328 #endif /* __ASM_AVR32_UACCESS_H */