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.
 101  *
 102  * This macro copies a single simple value from kernel space to user
 103  * space.  It supports simple types like char and int, but not larger
 104  * data types like structures or arrays.
 105  *
 106  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 107  * to the result of dereferencing @ptr.
 108  *
 109  * Returns zero on success, or -EFAULT on error.
 110  */
 111 #define put_user(x,ptr) \
 112         __put_user_check((x),(ptr),sizeof(*(ptr)))
 113
 114 /*
 115  * get_user: - Get a simple variable from user space.
 116  * @x:   Variable to store result.
 117  * @ptr: Source address, in user space.
 118  *
 119  * Context: User context only.  This function may sleep.
 120  *
 121  * This macro copies a single simple variable from user space to kernel
 122  * space.  It supports simple types like char and int, but not larger
 123  * data types like structures or arrays.
 124  *
 125  * @ptr must have pointer-to-simple-variable type, and the result of
 126  * dereferencing @ptr must be assignable to @x without a cast.
 127  *
 128  * Returns zero on success, or -EFAULT on error.
 129  * On error, the variable @x is set to zero.
 130  */
 131 #define get_user(x,ptr) \
 132         __get_user_check((x),(ptr),sizeof(*(ptr)))
 133
 134 /*
 135  * __put_user: - Write a simple value into user space, with less checking.
 136  * @x:   Value to copy to user space.
 137  * @ptr: Destination address, in user space.
 138  *
 139  * Context: User context only.  This function may sleep.
 140  *
 141  * This macro copies a single simple value from kernel space to user
 142  * space.  It supports simple types like char and int, but not larger
 143  * data types like structures or arrays.
 144  *
 145  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 146  * to the result of dereferencing @ptr.
 147  *
 148  * Caller must check the pointer with access_ok() before calling this
 149  * function.
 150  *
 151  * Returns zero on success, or -EFAULT on error.
 152  */
 153 #define __put_user(x,ptr) \
 154         __put_user_nocheck((x),(ptr),sizeof(*(ptr)))
 155
 156 /*
 157  * __get_user: - Get a simple variable from user space, with less checking.
 158  * @x:   Variable to store result.
 159  * @ptr: Source address, in user space.
 160  *
 161  * Context: User context only.  This function may sleep.
 162  *
 163  * This macro copies a single simple variable from user space to kernel
 164  * space.  It supports simple types like char and int, but not larger
 165  * data types like structures or arrays.
 166  *
 167  * @ptr must have pointer-to-simple-variable type, and the result of
 168  * dereferencing @ptr must be assignable to @x without a cast.
 169  *
 170  * Caller must check the pointer with access_ok() before calling this
 171  * function.
 172  *
 173  * Returns zero on success, or -EFAULT on error.
 174  * On error, the variable @x is set to zero.
 175  */
 176 #define __get_user(x,ptr) \
 177         __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
 178
 179 extern int __get_user_bad(void);
 180 extern int __put_user_bad(void);
 181
 182 #define __get_user_nocheck(x, ptr, size)                                \
 183 ({                                                                      \
 184         unsigned long __gu_val = 0;                                     \
 185         int __gu_err = 0;                                               \
 186                                                                         \
 187         switch (size) {                                                 \
 188         case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break;   \
 189         case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break;   \
 190         case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break;    \
 191         default: __gu_err = __get_user_bad(); break;                    \
 192         }                                                               \
 193                                                                         \
 194         x = (typeof(*(ptr)))__gu_val;                                   \
 195         __gu_err;                                                       \
 196 })
 197
 198 #define __get_user_check(x, ptr, size)                                  \
 199 ({                                                                      \
 200         unsigned long __gu_val = 0;                                     \
 201         const typeof(*(ptr)) __user * __gu_addr = (ptr);                \
 202         int __gu_err = 0;                                               \
 203                                                                         \
 204         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 205                 switch (size) {                                         \
 206                 case 1:                                                 \
 207                         __get_user_asm("ub", __gu_val, __gu_addr,       \
 208                                        __gu_err);                       \
 209                         break;                                          \
 210                 case 2:                                                 \
 211                         __get_user_asm("uh", __gu_val, __gu_addr,       \
 212                                        __gu_err);                       \
 213                         break;                                          \
 214                 case 4:                                                 \
 215                         __get_user_asm("w", __gu_val, __gu_addr,        \
 216                                        __gu_err);                       \
 217                         break;                                          \
 218                 default:                                                \
 219                         __gu_err = __get_user_bad();                    \
 220                         break;                                          \
 221                 }                                                       \
 222         } else {                                                        \
 223                 __gu_err = -EFAULT;                                     \
 224         }                                                               \
 225         x = (typeof(*(ptr)))__gu_val;                                   \
 226         __gu_err;                                                       \
 227 })
 228
 229 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err)                 \
 230         asm volatile(                                                   \
 231                 "1:     ld." suffix "   %1, %3                  \n"     \
 232                 "2:                                             \n"     \
 233                 "       .subsection 1                           \n"     \
 234                 "3:     mov     %0, %4                          \n"     \
 235                 "       rjmp    2b                              \n"     \
 236                 "       .subsection 0                           \n"     \
 237                 "       .section __ex_table, \"a\"              \n"     \
 238                 "       .long   1b, 3b                          \n"     \
 239                 "       .previous                               \n"     \
 240                 : "=r"(__gu_err), "=r"(__gu_val)                        \
 241                 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
 242
 243 #define __put_user_nocheck(x, ptr, size)                                \
 244 ({                                                                      \
 245         typeof(*(ptr)) __pu_val;                                        \
 246         int __pu_err = 0;                                               \
 247                                                                         \
 248         __pu_val = (x);                                                 \
 249         switch (size) {                                                 \
 250         case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break;    \
 251         case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break;    \
 252         case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break;    \
 253         case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break;    \
 254         default: __pu_err = __put_user_bad(); break;                    \
 255         }                                                               \
 256         __pu_err;                                                       \
 257 })
 258
 259 #define __put_user_check(x, ptr, size)                                  \
 260 ({                                                                      \
 261         typeof(*(ptr)) __pu_val;                                        \
 262         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 263         int __pu_err = 0;                                               \
 264                                                                         \
 265         __pu_val = (x);                                                 \
 266         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 267                 switch (size) {                                         \
 268                 case 1:                                                 \
 269                         __put_user_asm("b", __pu_addr, __pu_val,        \
 270                                        __pu_err);                       \
 271                         break;                                          \
 272                 case 2:                                                 \
 273                         __put_user_asm("h", __pu_addr, __pu_val,        \
 274                                        __pu_err);                       \
 275                         break;                                          \
 276                 case 4:                                                 \
 277                         __put_user_asm("w", __pu_addr, __pu_val,        \
 278                                        __pu_err);                       \
 279                         break;                                          \
 280                 case 8:                                                 \
 281                         __put_user_asm("d", __pu_addr, __pu_val,                \
 282                                        __pu_err);                       \
 283                         break;                                          \
 284                 default:                                                \
 285                         __pu_err = __put_user_bad();                    \
 286                         break;                                          \
 287                 }                                                       \
 288         } else {                                                        \
 289                 __pu_err = -EFAULT;                                     \
 290         }                                                               \
 291         __pu_err;                                                       \
 292 })
 293
 294 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err)                 \
 295         asm volatile(                                                   \
 296                 "1:     st." suffix "   %1, %3                  \n"     \
 297                 "2:                                             \n"     \
 298                 "       .subsection 1                           \n"     \
 299                 "3:     mov     %0, %4                          \n"     \
 300                 "       rjmp    2b                              \n"     \
 301                 "       .subsection 0                           \n"     \
 302                 "       .section __ex_table, \"a\"              \n"     \
 303                 "       .long   1b, 3b                          \n"     \
 304                 "       .previous                               \n"     \
 305                 : "=r"(__gu_err), "=m"(*(ptr))                          \
 306                 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
 307
 308 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
 309 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
 310
 311 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 312 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 313
 314 extern long strnlen_user(const char __user *__s, long __n);
 315 extern long __strnlen_user(const char __user *__s, long __n);
 316
 317 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
 318
 319 struct exception_table_entry
 320 {
 321         unsigned long insn, fixup;
 322 };
 323
 324 #endif /* __ASM_AVR32_UACCESS_H */