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 if pagefaults are
 110  *          enabled.
 111  *
 112  * This macro copies a single simple value from kernel space to user
 113  * space.  It supports simple types like char and int, but not larger
 114  * data types like structures or arrays.
 115  *
 116  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 117  * to the result of dereferencing @ptr.
 118  *
 119  * Returns zero on success, or -EFAULT on error.
 120  */
 121 #define put_user(x, ptr)        \
 122         __put_user_check((x), (ptr), sizeof(*(ptr)))
 123
 124 /*
 125  * get_user: - Get a simple variable from user space.
 126  * @x:   Variable to store result.
 127  * @ptr: Source address, in user space.
 128  *
 129  * Context: User context only. This function may sleep if pagefaults are
 130  *          enabled.
 131  *
 132  * This macro copies a single simple variable from user space to kernel
 133  * space.  It supports simple types like char and int, but not larger
 134  * data types like structures or arrays.
 135  *
 136  * @ptr must have pointer-to-simple-variable type, and the result of
 137  * dereferencing @ptr must be assignable to @x without a cast.
 138  *
 139  * Returns zero on success, or -EFAULT on error.
 140  * On error, the variable @x is set to zero.
 141  */
 142 #define get_user(x, ptr) \
 143         __get_user_check((x), (ptr), sizeof(*(ptr)))
 144
 145 /*
 146  * __put_user: - Write a simple value into user space, with less checking.
 147  * @x:   Value to copy to user space.
 148  * @ptr: Destination address, in user space.
 149  *
 150  * Context: User context only. This function may sleep if pagefaults are
 151  *          enabled.
 152  *
 153  * This macro copies a single simple value from kernel space to user
 154  * space.  It supports simple types like char and int, but not larger
 155  * data types like structures or arrays.
 156  *
 157  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 158  * to the result of dereferencing @ptr.
 159  *
 160  * Caller must check the pointer with access_ok() before calling this
 161  * function.
 162  *
 163  * Returns zero on success, or -EFAULT on error.
 164  */
 165 #define __put_user(x, ptr) \
 166         __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
 167
 168 /*
 169  * __get_user: - Get a simple variable from user space, with less checking.
 170  * @x:   Variable to store result.
 171  * @ptr: Source address, in user space.
 172  *
 173  * Context: User context only. This function may sleep if pagefaults are
 174  *          enabled.
 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  * Caller must check the pointer with access_ok() before calling this
 184  * function.
 185  *
 186  * Returns zero on success, or -EFAULT on error.
 187  * On error, the variable @x is set to zero.
 188  */
 189 #define __get_user(x, ptr) \
 190         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 191
 192 extern int __get_user_bad(void);
 193 extern int __put_user_bad(void);
 194
 195 #define __get_user_nocheck(x, ptr, size)                                \
 196 ({                                                                      \
 197         unsigned long __gu_val = 0;                                     \
 198         int __gu_err = 0;                                               \
 199                                                                         \
 200         switch (size) {                                                 \
 201         case 1: __get_user_asm("ub", __gu_val, ptr, __gu_err); break;   \
 202         case 2: __get_user_asm("uh", __gu_val, ptr, __gu_err); break;   \
 203         case 4: __get_user_asm("w", __gu_val, ptr, __gu_err); break;    \
 204         default: __gu_err = __get_user_bad(); break;                    \
 205         }                                                               \
 206                                                                         \
 207         x = (__force typeof(*(ptr)))__gu_val;                           \
 208         __gu_err;                                                       \
 209 })
 210
 211 #define __get_user_check(x, ptr, size)                                  \
 212 ({                                                                      \
 213         unsigned long __gu_val = 0;                                     \
 214         const typeof(*(ptr)) __user * __gu_addr = (ptr);                \
 215         int __gu_err = 0;                                               \
 216                                                                         \
 217         if (access_ok(VERIFY_READ, __gu_addr, size)) {                  \
 218                 switch (size) {                                         \
 219                 case 1:                                                 \
 220                         __get_user_asm("ub", __gu_val, __gu_addr,       \
 221                                        __gu_err);                       \
 222                         break;                                          \
 223                 case 2:                                                 \
 224                         __get_user_asm("uh", __gu_val, __gu_addr,       \
 225                                        __gu_err);                       \
 226                         break;                                          \
 227                 case 4:                                                 \
 228                         __get_user_asm("w", __gu_val, __gu_addr,        \
 229                                        __gu_err);                       \
 230                         break;                                          \
 231                 default:                                                \
 232                         __gu_err = __get_user_bad();                    \
 233                         break;                                          \
 234                 }                                                       \
 235         } else {                                                        \
 236                 __gu_err = -EFAULT;                                     \
 237         }                                                               \
 238         x = (__force typeof(*(ptr)))__gu_val;                           \
 239         __gu_err;                                                       \
 240 })
 241
 242 #define __get_user_asm(suffix, __gu_val, ptr, __gu_err)                 \
 243         asm volatile(                                                   \
 244                 "1:     ld." suffix "   %1, %3                  \n"     \
 245                 "2:                                             \n"     \
 246                 "       .subsection 1                           \n"     \
 247                 "3:     mov     %0, %4                          \n"     \
 248                 "       rjmp    2b                              \n"     \
 249                 "       .subsection 0                           \n"     \
 250                 "       .section __ex_table, \"a\"              \n"     \
 251                 "       .long   1b, 3b                          \n"     \
 252                 "       .previous                               \n"     \
 253                 : "=r"(__gu_err), "=r"(__gu_val)                        \
 254                 : "0"(__gu_err), "m"(*(ptr)), "i"(-EFAULT))
 255
 256 #define __put_user_nocheck(x, ptr, size)                                \
 257 ({                                                                      \
 258         typeof(*(ptr)) __pu_val;                                        \
 259         int __pu_err = 0;                                               \
 260                                                                         \
 261         __pu_val = (x);                                                 \
 262         switch (size) {                                                 \
 263         case 1: __put_user_asm("b", ptr, __pu_val, __pu_err); break;    \
 264         case 2: __put_user_asm("h", ptr, __pu_val, __pu_err); break;    \
 265         case 4: __put_user_asm("w", ptr, __pu_val, __pu_err); break;    \
 266         case 8: __put_user_asm("d", ptr, __pu_val, __pu_err); break;    \
 267         default: __pu_err = __put_user_bad(); break;                    \
 268         }                                                               \
 269         __pu_err;                                                       \
 270 })
 271
 272 #define __put_user_check(x, ptr, size)                                  \
 273 ({                                                                      \
 274         typeof(*(ptr)) __pu_val;                                        \
 275         typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 276         int __pu_err = 0;                                               \
 277                                                                         \
 278         __pu_val = (x);                                                 \
 279         if (access_ok(VERIFY_WRITE, __pu_addr, size)) {                 \
 280                 switch (size) {                                         \
 281                 case 1:                                                 \
 282                         __put_user_asm("b", __pu_addr, __pu_val,        \
 283                                        __pu_err);                       \
 284                         break;                                          \
 285                 case 2:                                                 \
 286                         __put_user_asm("h", __pu_addr, __pu_val,        \
 287                                        __pu_err);                       \
 288                         break;                                          \
 289                 case 4:                                                 \
 290                         __put_user_asm("w", __pu_addr, __pu_val,        \
 291                                        __pu_err);                       \
 292                         break;                                          \
 293                 case 8:                                                 \
 294                         __put_user_asm("d", __pu_addr, __pu_val,        \
 295                                        __pu_err);                       \
 296                         break;                                          \
 297                 default:                                                \
 298                         __pu_err = __put_user_bad();                    \
 299                         break;                                          \
 300                 }                                                       \
 301         } else {                                                        \
 302                 __pu_err = -EFAULT;                                     \
 303         }                                                               \
 304         __pu_err;                                                       \
 305 })
 306
 307 #define __put_user_asm(suffix, ptr, __pu_val, __gu_err)                 \
 308         asm volatile(                                                   \
 309                 "1:     st." suffix "   %1, %3                  \n"     \
 310                 "2:                                             \n"     \
 311                 "       .subsection 1                           \n"     \
 312                 "3:     mov     %0, %4                          \n"     \
 313                 "       rjmp    2b                              \n"     \
 314                 "       .subsection 0                           \n"     \
 315                 "       .section __ex_table, \"a\"              \n"     \
 316                 "       .long   1b, 3b                          \n"     \
 317                 "       .previous                               \n"     \
 318                 : "=r"(__gu_err), "=m"(*(ptr))                          \
 319                 : "0"(__gu_err), "r"(__pu_val), "i"(-EFAULT))
 320
 321 extern __kernel_size_t clear_user(void __user *addr, __kernel_size_t size);
 322 extern __kernel_size_t __clear_user(void __user *addr, __kernel_size_t size);
 323
 324 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 325 extern long __strncpy_from_user(char *dst, const char __user *src, long count);
 326
 327 extern long strnlen_user(const char __user *__s, long __n);
 328 extern long __strnlen_user(const char __user *__s, long __n);
 329
 330 #define strlen_user(s) strnlen_user(s, ~0UL >> 1)
 331
 332 struct exception_table_entry
 333 {
 334         unsigned long insn, fixup;
 335 };
 336
 337 #endif /* __ASM_AVR32_UACCESS_H */