include/asm-arm/uaccess.h

   1 #ifndef _ASMARM_UACCESS_H
   2 #define _ASMARM_UACCESS_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7 #include <linux/sched.h>
   8 #include <asm/errno.h>
   9
  10 #define VERIFY_READ 0
  11 #define VERIFY_WRITE 1
  12
  13 /*
  14  * The exception table consists of pairs of addresses: the first is the
  15  * address of an instruction that is allowed to fault, and the second is
  16  * the address at which the program should continue.  No registers are
  17  * modified, so it is entirely up to the continuation code to figure out
  18  * what to do.
  19  *
  20  * All the routines below use bits of fixup code that are out of line
  21  * with the main instruction path.  This means when everything is well,
  22  * we don't even have to jump over them.  Further, they do not intrude
  23  * on our cache or tlb entries.
  24  */
  25
  26 struct exception_table_entry
  27 {
  28         unsigned long insn, fixup;
  29 };
  30
  31 /* Returns 0 if exception not found and fixup otherwise.  */
  32 extern unsigned long search_exception_table(unsigned long);
  33
  34 #define get_ds()        (KERNEL_DS)
  35 #define get_fs()        (current->addr_limit)
  36 #define segment_eq(a,b) ((a) == (b))
  37
  38 #include <asm/proc/uaccess.h>
  39
  40 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
  41
  42 extern __inline__ int verify_area(int type, const void * addr, unsigned long size)
  43 {
  44         return access_ok(type, addr, size) ? 0 : -EFAULT;
  45 }
  46
  47 /*
  48  * Single-value transfer routines.  They automatically use the right
  49  * size if we just have the right pointer type.  Note that the functions
  50  * which read from user space (*get_*) need to take care not to leak
  51  * kernel data even if the calling code is buggy and fails to check
  52  * the return value.  This means zeroing out the destination variable
  53  * or buffer on error.  Normally this is done out of line by the
  54  * fixup code, but there are a few places where it intrudes on the
  55  * main code path.  When we only write to user space, there is no
  56  * problem.
  57  *
  58  * The "__xxx" versions of the user access functions do not verify the
  59  * address space - it must have been done previously with a separate
  60  * "access_ok()" call.
  61  *
  62  * The "xxx_error" versions set the third argument to EFAULT if an
  63  * error occurs, and leave it unchanged on success.  Note that these
  64  * versions are void (ie, don't return a value as such).
  65  */
  66 #define get_user(x,p)           __get_user_check((x),(p),sizeof(*(p)))
  67 #define __get_user(x,p)         __get_user_nocheck((x),(p),sizeof(*(p)))
  68 #define __get_user_error(x,p,e) __get_user_nocheck_error((x),(p),sizeof(*(p)),(e))
  69
  70 #define put_user(x,p)           __put_user_check((__typeof(*(p)))(x),(p),sizeof(*(p)))
  71 #define __put_user(x,p)         __put_user_nocheck((__typeof(*(p)))(x),(p),sizeof(*(p)))
  72 #define __put_user_error(x,p,e) __put_user_nocheck_error((x),(p),sizeof(*(p)),(e))
  73
  74 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
  75 {
  76         if (access_ok(VERIFY_READ, from, n))
  77                 __do_copy_from_user(to, from, n);
  78         return n;
  79 }
  80
  81 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
  82 {
  83         __do_copy_from_user(to, from, n);
  84         return n;
  85 }
  86
  87 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
  88 {
  89         if (access_ok(VERIFY_WRITE, to, n))
  90                 __do_copy_to_user(to, from, n);
  91         return n;
  92 }
  93
  94 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
  95 {
  96         __do_copy_to_user(to, from, n);
  97         return n;
  98 }
  99
 100 static __inline__ unsigned long clear_user (void *to, unsigned long n)
 101 {
 102         if (access_ok(VERIFY_WRITE, to, n))
 103                 __do_clear_user(to, n);
 104         return n;
 105 }
 106
 107 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
 108 {
 109         __do_clear_user(to, n);
 110         return n;
 111 }
 112
 113 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
 114 {
 115         long res = -EFAULT;
 116         if (access_ok(VERIFY_READ, src, 1))
 117                 __do_strncpy_from_user(dst, src, count, res);
 118         return res;
 119 }
 120
 121 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
 122 {
 123         long res;
 124         __do_strncpy_from_user(dst, src, count, res);
 125         return res;
 126 }
 127
 128 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 129
 130 extern __inline__ long strnlen_user(const char *s, long n)
 131 {
 132         unsigned long res = 0;
 133
 134         if (__addr_ok(s))
 135                 __do_strnlen_user(s, n, res);
 136
 137         return res;
 138 }
 139
 140 /*
 141  * These are the work horses of the get/put_user functions
 142  */
 143 #define __get_user_check(x,ptr,size)                                    \
 144 ({                                                                      \
 145         long __gu_err = -EFAULT, __gu_val = 0;                          \
 146         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 147         if (access_ok(VERIFY_READ,__gu_addr,size)) {                    \
 148                 __gu_err = 0;                                           \
 149                 __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
 150         }                                                               \
 151         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 152         __gu_err;                                                       \
 153 })
 154
 155 #define __get_user_nocheck(x,ptr,size)                                  \
 156 ({                                                                      \
 157         long __gu_err = 0, __gu_val;                                    \
 158         __get_user_size(__gu_val,(ptr),(size),__gu_err);                \
 159         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 160         __gu_err;                                                       \
 161 })
 162
 163 #define __get_user_nocheck_error(x,ptr,size,err)                        \
 164 ({                                                                      \
 165         long __gu_val;                                                  \
 166         __get_user_size(__gu_val,(ptr),(size),(err));                   \
 167         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 168         (void) 0;                                                       \
 169 })
 170
 171 #define __put_user_check(x,ptr,size)                                    \
 172 ({                                                                      \
 173         long __pu_err = -EFAULT;                                        \
 174         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 175         if (access_ok(VERIFY_WRITE,__pu_addr,size)) {                   \
 176                 __pu_err = 0;                                           \
 177                 __put_user_size((x),__pu_addr,(size),__pu_err);         \
 178         }                                                               \
 179         __pu_err;                                                       \
 180 })
 181
 182 #define __put_user_nocheck(x,ptr,size)                                  \
 183 ({                                                                      \
 184         long __pu_err = 0;                                              \
 185         __put_user_size((x),(ptr),(size),__pu_err);                     \
 186         __pu_err;                                                       \
 187 })
 188
 189 #define __put_user_nocheck_error(x,ptr,size,err)                        \
 190 ({                                                                      \
 191         __put_user_size((x),(ptr),(size),err);                          \
 192         (void) 0;                                                       \
 193 })
 194
 195 extern long __get_user_bad(void);
 196
 197 #define __get_user_size(x,ptr,size,retval)                              \
 198 do {                                                                    \
 199         switch (size) {                                                 \
 200         case 1: __get_user_asm_byte(x,ptr,retval);      break;          \
 201         case 2: __get_user_asm_half(x,ptr,retval);      break;          \
 202         case 4: __get_user_asm_word(x,ptr,retval);      break;          \
 203         default: (x) = __get_user_bad();                                \
 204         }                                                               \
 205 } while (0)
 206
 207 extern long __put_user_bad(void);
 208
 209 #define __put_user_size(x,ptr,size,retval)                              \
 210 do {                                                                    \
 211         switch (size) {                                                 \
 212         case 1: __put_user_asm_byte(x,ptr,retval);      break;          \
 213         case 2: __put_user_asm_half(x,ptr,retval);      break;          \
 214         case 4: __put_user_asm_word(x,ptr,retval);      break;          \
 215         default: __put_user_bad();                                      \
 216         }                                                               \
 217 } while (0)
 218
 219 #endif /* _ASMARM_UACCESS_H */