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
   9 #define VERIFY_READ 0
  10 #define VERIFY_WRITE 1
  11
  12 /*
  13  * The exception table consists of pairs of addresses: the first is the
  14  * address of an instruction that is allowed to fault, and the second is
  15  * the address at which the program should continue.  No registers are
  16  * modified, so it is entirely up to the continuation code to figure out
  17  * what to do.
  18  *
  19  * All the routines below use bits of fixup code that are out of line
  20  * with the main instruction path.  This means when everything is well,
  21  * we don't even have to jump over them.  Further, they do not intrude
  22  * on our cache or tlb entries.
  23  */
  24
  25 struct exception_table_entry
  26 {
  27         unsigned long insn, fixup;
  28 };
  29
  30 /* Returns 0 if exception not found and fixup otherwise.  */
  31 extern unsigned long search_exception_table(unsigned long);
  32
  33 #include <asm/proc/uaccess.h>
  34
  35 extern inline int verify_area(int type, const void * addr, unsigned long size)
  36 {
  37         return access_ok(type,addr,size) ? 0 : -EFAULT;
  38 }
  39
  40 /*
  41  * Single-value transfer routines.  They automatically use the right
  42  * size if we just have the right pointer type.
  43  *
  44  * The "__xxx" versions of the user access functions do not verify the
  45  * address space - it must have been done previously with a separate
  46  * "access_ok()" call.
  47  *
  48  * The "xxx_ret" versions return constant specified in the third
  49  * argument if something bad happens.
  50  */
  51 #define get_user(x,p)           __get_user_check((x),(p),sizeof(*(p)))
  52 #define __get_user(x,p)         __get_user_nocheck((x),(p),sizeof(*(p)))
  53 #define get_user_ret(x,p,r)     ({ if (get_user(x,p)) return r; })
  54 #define __get_user_ret(x,p,r)   ({ if (__get_user(x,p)) return r; })
  55
  56 #define put_user(x,p)           __put_user_check((__typeof(*(p)))(x),(p),sizeof(*(p)))
  57 #define __put_user(x,p)         __put_user_nocheck((__typeof(*(p)))(x),(p),sizeof(*(p)))
  58 #define put_user_ret(x,p,r)     ({ if (put_user(x,p)) return r; })
  59 #define __put_user_ret(x,p,r)   ({ if (__put_user(x,p)) return r; })
  60
  61 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
  62 {
  63         char *end = (char *)to + n;
  64         if (access_ok(VERIFY_READ, from, n)) {
  65                 __do_copy_from_user(to, from, n);
  66                 if (n) memset(end - n, 0, n);
  67         }
  68         return n;
  69 }
  70
  71 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
  72 {
  73         __do_copy_from_user(to, from, n);
  74         return n;
  75 }
  76
  77 #define copy_from_user_ret(t,f,n,r)                                     \
  78         ({ if (copy_from_user(t,f,n)) return r; })
  79
  80 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
  81 {
  82         if (access_ok(VERIFY_WRITE, to, n))
  83                 __do_copy_to_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         __do_copy_to_user(to, from, n);
  90         return n;
  91 }
  92
  93 #define copy_to_user_ret(t,f,n,r)                                       \
  94         ({ if (copy_to_user(t,f,n)) return r; })
  95
  96 static __inline__ unsigned long clear_user (void *to, unsigned long n)
  97 {
  98         if (access_ok(VERIFY_WRITE, to, n))
  99                 __do_clear_user(to, n);
 100         return n;
 101 }
 102
 103 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
 104 {
 105         __do_clear_user(to, n);
 106         return n;
 107 }
 108
 109 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
 110 {
 111         long res = -EFAULT;
 112         if (access_ok(VERIFY_READ, src, 1))
 113                 __do_strncpy_from_user(dst, src, count, res);
 114         return res;
 115 }
 116
 117 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
 118 {
 119         long res;
 120         __do_strncpy_from_user(dst, src, count, res);
 121         return res;
 122 }
 123
 124 extern __inline__ long strlen_user (const char *s)
 125 {
 126         unsigned long res = 0;
 127
 128         if (__addr_ok(s))
 129                 __do_strlen_user (s, res);
 130
 131         return res;
 132 }
 133
 134 /*
 135  * These are the work horses of the get/put_user functions
 136  */
 137 #define __get_user_check(x,ptr,size)                                    \
 138 ({                                                                      \
 139         long __gu_err = -EFAULT, __gu_val = 0;                          \
 140         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 141         if (access_ok(VERIFY_READ,__gu_addr,size))                      \
 142                 __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
 143         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 144         __gu_err;                                                       \
 145 })
 146
 147 #define __get_user_nocheck(x,ptr,size)                                  \
 148 ({                                                                      \
 149         long __gu_err = 0, __gu_val = 0;                                \
 150         __get_user_size(__gu_val,(ptr),(size),__gu_err);                \
 151         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 152         __gu_err;                                                       \
 153 })
 154
 155 #define __put_user_check(x,ptr,size)                                    \
 156 ({                                                                      \
 157         long __pu_err = -EFAULT;                                        \
 158         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 159         if (access_ok(VERIFY_WRITE,__pu_addr,size))                     \
 160                 __put_user_size((x),__pu_addr,(size),__pu_err);         \
 161         __pu_err;                                                       \
 162 })
 163
 164 #define __put_user_nocheck(x,ptr,size)                                  \
 165 ({                                                                      \
 166         long __pu_err = 0;                                              \
 167         __put_user_size((x),(ptr),(size),__pu_err);                     \
 168         __pu_err;                                                       \
 169 })
 170
 171 extern long __get_user_bad(void);
 172
 173 #define __get_user_size(x,ptr,size,retval)                              \
 174 do {                                                                    \
 175         retval = 0;                                                     \
 176         switch (size) {                                                 \
 177         case 1: __get_user_asm_byte(x,ptr,retval);      break;          \
 178         case 2: __get_user_asm_half(x,ptr,retval);      break;          \
 179         case 4: __get_user_asm_word(x,ptr,retval);      break;          \
 180         default: (x) = __get_user_bad();                                \
 181         }                                                               \
 182 } while (0)
 183
 184 extern long __put_user_bad(void);
 185
 186 #define __put_user_size(x,ptr,size,retval)                              \
 187 do {                                                                    \
 188         retval = 0;                                                     \
 189         switch (size) {                                                 \
 190         case 1: __put_user_asm_byte(x,ptr,retval);      break;          \
 191         case 2: __put_user_asm_half(x,ptr,retval);      break;          \
 192         case 4: __put_user_asm_word(x,ptr,retval);      break;          \
 193         default: __put_user_bad();                                      \
 194         }                                                               \
 195 } while (0)
 196
 197 #endif /* _ASMARM_UACCESS_H */