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 static inline __kernel_size_t copy_from_user(void *to,
  92                                                const void __user *from,
  93                                                __kernel_size_t n)
  94 {
  95         size_t res = ___copy_from_user(to, from, n);
  96         if (unlikely(res))
  97                 memset(to + (n - res), 0, res);
  98         return res;
  99 }
 100
 101 #define __copy_to_user_inatomic __copy_to_user
 102 #define __copy_from_user_inatomic __copy_from_user
 103
 104 /*
 105  * put_user: - Write a simple value into user space.
 106  * @x:   Value to copy to user space.
 107  * @ptr: Destination address, in user space.
 108  *
 109  * Context: User context only.  This function may sleep.
 110  *
 111  * This macro copies a single simple value from kernel space to user
 112  * space.  It supports simple types like char and int, but not larger
 113  * data types like structures or arrays.
 114  *
 115  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 116  * to the result of dereferencing @ptr.
 117  *
 118  * Returns zero on success, or -EFAULT on error.
 119  */
 120 #define put_user(x,ptr) \
 121         __put_user_check((x),(ptr),sizeof(*(ptr)))
 122
 123 /*
 124  * get_user: - Get a simple variable from user space.
 125  * @x:   Variable to store result.
 126  * @ptr: Source address, in user space.
 127  *
 128  * Context: User context only.  This function may sleep.
 129  *
 130  * This macro copies a single simple variable from user space to kernel
 131  * space.  It supports simple types like char and int, but not larger
 132  * data types like structures or arrays.
 133  *
 134  * @ptr must have pointer-to-simple-variable type, and the result of
 135  * dereferencing @ptr must be assignable to @x without a cast.
 136  *
 137  * Returns zero on success, or -EFAULT on error.
 138  * On error, the variable @x is set to zero.
 139  */
 140 #define get_user(x,ptr) \
 141         __get_user_check((x),(ptr),sizeof(*(ptr)))
 142
 143 /*
 144  * __put_user: - Write a simple value into user space, with less checking.
 145  * @x:   Value to copy to user space.
 146  * @ptr: Destination address, in user space.
 147  *
 148  * Context: User context only.  This function may sleep.
 149  *
 150  * This macro copies a single simple value from kernel space to user
 151  * space.  It supports simple types like char and int, but not larger
 152  * data types like structures or arrays.
 153  *
 154  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 155  * to the result of dereferencing @ptr.
 156  *
 157  * Caller must check the pointer with access_ok() before calling this
 158  * function.
 159  *
 160  * Returns zero on success, or -EFAULT on error.
 161  */
 162 #define __put_user(x,ptr) \
 163         __put_user_nocheck((x),(ptr),sizeof(*(ptr)))
 164
 165 /*
 166  * __get_user: - Get a simple variable from user space, with less checking.
 167  * @x:   Variable to store result.
 168  * @ptr: Source address, in user space.
 169  *
 170  * Context: User context only.  This function may sleep.
 171  *
 172  * This macro copies a single simple variable from user space to kernel
 173  * space.  It supports simple types like char and int, but not larger
 174  * data types like structures or arrays.
 175  *
 176  * @ptr must have pointer-to-simple-variable type, and the result of
 177  * dereferencing @ptr must be assignable to @x without a cast.
 178  *
 179  * Caller must check the pointer with access_ok() before calling this
 180  * function.
 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_nocheck((x),(ptr),sizeof(*(ptr)))
 187
 188 extern int __get_user_bad(void);
 189 extern int __put_user_bad(void);
 190
 191 #define __get_user_nocheck(x, ptr, size)                                \
 192 ({                                                                      \
 193         unsigned long __gu_val = 0;                                     \
 194         int __gu_err = 0;                                               \
 195                                                                         \
 196         switch (size) {                                                 \
 197         case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break;   \
 198         case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break;   \
 199         case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break;    \
 200         default: __gu_err = __get_user_bad(); break;                    \
 201         }                                                               \
 202                                                                         \
 203         x = (typeof(*(ptr)))__gu_val;                                   \
 204         __gu_err;                                                       \
 205 })
 206
 207 #define __get_user_check(x, ptr, size)                                  \
 208 ({                                                                      \
 209         unsigned long __gu_val = 0;                                     \
 210         const typeof(*(ptr)) __user * __gu_addr = (ptr);                \
 211         int __gu_err = 0;                                               \
 212                                                                         \
 213         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 214                 switch (size) {                                         \
 215                 case 1:                                                 \
 216                         __get_user_asm("ub", __gu_val, __gu_addr,       \
 217                                        __gu_err);                       \
 218                         break;                                          \
 219                 case 2:                                                 \
 220                         __get_user_asm("uh", __gu_val, __gu_addr,       \
 221                                        __gu_err);                       \
 222                         break;                                          \
 223                 case 4:                                                 \
 224                         __get_user_asm("w", __gu_val, __gu_addr,        \
 225                                        __gu_err);                       \
 226                         break;                                          \
 227                 default:                                                \
 228                         __gu_err = __get_user_bad();                    \
 229                         break;                                          \
 230                 }                                                       \
 231         } else {                                                        \
 232                 __gu_err = -EFAULT;                                     \
 233         }                                                               \
 234         x = (typeof(*(ptr)))__gu_val;                                   \
 235         __gu_err;                                                       \
 236 })
 237
 238 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err)                 \
 239         asm volatile(                                                   \
 240                 "1:     ld." suffix "   %1, %3                  \n"     \
 241                 "2:                                             \n"     \
 242                 "       .subsection 1                           \n"     \
 243                 "3:     mov     %0, %4                          \n"     \
 244                 "       rjmp    2b                              \n"     \
 245                 "       .subsection 0                           \n"     \
 246                 "       .section __ex_table, \"a\"              \n"     \
 247                 "       .long   1b, 3b                          \n"     \
 248                 "       .previous                               \n"     \
 249                 : "=r"(__gu_err), "=r"(__gu_val)                        \
 250                 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
 251
 252 #define __put_user_nocheck(x, ptr, size)                                \
 253 ({                                                                      \
 254         typeof(*(ptr)) __pu_val;                                        \
 255         int __pu_err = 0;                                               \
 256                                                                         \
 257         __pu_val = (x);                                                 \
 258         switch (size) {                                                 \
 259         case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break;    \
 260         case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break;    \
 261         case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break;    \
 262         case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break;    \
 263         default: __pu_err = __put_user_bad(); break;                    \
 264         }                                                               \
 265         __pu_err;                                                       \
 266 })
 267
 268 #define __put_user_check(x, ptr, size)                                  \
 269 ({                                                                      \
 270         typeof(*(ptr)) __pu_val;                                        \
 271         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 272         int __pu_err = 0;                                               \
 273                                                                         \
 274         __pu_val = (x);                                                 \
 275         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 276                 switch (size) {                                         \
 277                 case 1:                                                 \
 278                         __put_user_asm("b", __pu_addr, __pu_val,        \
 279                                        __pu_err);                       \
 280                         break;                                          \
 281                 case 2:                                                 \
 282                         __put_user_asm("h", __pu_addr, __pu_val,        \
 283                                        __pu_err);                       \
 284                         break;                                          \
 285                 case 4:                                                 \
 286                         __put_user_asm("w", __pu_addr, __pu_val,        \
 287                                        __pu_err);                       \
 288                         break;                                          \
 289                 case 8:                                                 \
 290                         __put_user_asm("d", __pu_addr, __pu_val,                \
 291                                        __pu_err);                       \
 292                         break;                                          \
 293                 default:                                                \
 294                         __pu_err = __put_user_bad();                    \
 295                         break;                                          \
 296                 }                                                       \
 297         } else {                                                        \
 298                 __pu_err = -EFAULT;                                     \
 299         }                                                               \
 300         __pu_err;                                                       \
 301 })
 302
 303 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err)                 \
 304         asm volatile(                                                   \
 305                 "1:     st." suffix "   %1, %3                  \n"     \
 306                 "2:                                             \n"     \
 307                 "       .subsection 1                           \n"     \
 308                 "3:     mov     %0, %4                          \n"     \
 309                 "       rjmp    2b                              \n"     \
 310                 "       .subsection 0                           \n"     \
 311                 "       .section __ex_table, \"a\"              \n"     \
 312                 "       .long   1b, 3b                          \n"     \
 313                 "       .previous                               \n"     \
 314                 : "=r"(__gu_err), "=m"(*(ptr))                          \
 315                 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
 316
 317 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
 318 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
 319
 320 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 321 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 322
 323 extern long strnlen_user(const char __user *__s, long __n);
 324 extern long __strnlen_user(const char __user *__s, long __n);
 325
 326 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
 327
 328 struct exception_table_entry
 329 {
 330         unsigned long insn, fixup;
 331 };
 332
 333 #endif /* __ASM_AVR32_UACCESS_H */