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 static 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
  67 extern int __get_user_1(void *);
  68 extern int __get_user_2(void *);
  69 extern int __get_user_4(void *);
  70 extern int __get_user_8(void *);
  71 extern int __get_user_bad(void);
  72
  73 #define __get_user_x(__r1,__p,__e,__s,__i...)                           \
  74            __asm__ __volatile__ ("bl    __get_user_" #__s               \
  75                 : "=&r" (__e), "=r" (__r1)                              \
  76                 : "0" (__p)                                             \
  77                 : __i)
  78
  79 #define get_user(x,p)                                                   \
  80         ({                                                              \
  81                 const register typeof(*(p)) *__p asm("r0") = (p);       \
  82                 register typeof(*(p)) __r1 asm("r1");                   \
  83                 register int __e asm("r0");                             \
  84                 switch (sizeof(*(p))) {                                 \
  85                 case 1:                                                 \
  86                         __get_user_x(__r1, __p, __e, 1, "lr");          \
  87                         break;                                          \
  88                 case 2:                                                 \
  89                         __get_user_x(__r1, __p, __e, 2, "r2", "lr");    \
  90                         break;                                          \
  91                 case 4:                                                 \
  92                         __get_user_x(__r1, __p, __e, 4, "lr");          \
  93                         break;                                          \
  94                 case 8:                                                 \
  95                         __get_user_x(__r1, __p, __e, 8, "lr");          \
  96                         break;                                          \
  97                 default: __e = __get_user_bad(); break;                 \
  98                 }                                                       \
  99                 x = __r1;                                               \
 100                 __e;                                                    \
 101         })
 102
 103 #define __get_user(x,p)         __get_user_nocheck((x),(p),sizeof(*(p)))
 104 #define __get_user_error(x,p,e) __get_user_nocheck_error((x),(p),sizeof(*(p)),(e))
 105
 106 extern int __put_user_1(void *, unsigned int);
 107 extern int __put_user_2(void *, unsigned int);
 108 extern int __put_user_4(void *, unsigned int);
 109 extern int __put_user_8(void *, unsigned long long);
 110 extern int __put_user_bad(void);
 111
 112 #define __put_user_x(__r1,__p,__e,__s,__i...)                           \
 113            __asm__ __volatile__ ("bl    __put_user_" #__s               \
 114                 : "=&r" (__e)                                           \
 115                 : "0" (__p), "r" (__r1)                                 \
 116                 : __i)
 117
 118 #define put_user(x,p)                                                   \
 119         ({                                                              \
 120                 const register typeof(*(p)) __r1 asm("r1") = (x);       \
 121                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 122                 register int __e asm("r0");                             \
 123                 switch (sizeof(*(p))) {                                 \
 124                 case 1:                                                 \
 125                         __put_user_x(__r1, __p, __e, 1, "r2", "lr");    \
 126                         break;                                          \
 127                 case 2:                                                 \
 128                         __put_user_x(__r1, __p, __e, 2, "r2", "lr");    \
 129                         break;                                          \
 130                 case 4:                                                 \
 131                         __put_user_x(__r1, __p, __e, 4, "r2", "lr");    \
 132                         break;                                          \
 133                 case 8:                                                 \
 134                         __put_user_x(__r1, __p, __e, 8, "ip", "lr");    \
 135                         break;                                          \
 136                 default: __e = __put_user_bad(); break;                 \
 137                 }                                                       \
 138                 __e;                                                    \
 139         })
 140
 141 #define __put_user(x,p)         __put_user_nocheck((__typeof(*(p)))(x),(p),sizeof(*(p)))
 142 #define __put_user_error(x,p,e) __put_user_nocheck_error((x),(p),sizeof(*(p)),(e))
 143
 144 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
 145 {
 146         if (access_ok(VERIFY_READ, from, n))
 147                 __do_copy_from_user(to, from, n);
 148         else /* security hole - plug it */
 149                 memzero(to, n);
 150         return n;
 151 }
 152
 153 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
 154 {
 155         __do_copy_from_user(to, from, n);
 156         return n;
 157 }
 158
 159 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
 160 {
 161         if (access_ok(VERIFY_WRITE, to, n))
 162                 __do_copy_to_user(to, from, n);
 163         return n;
 164 }
 165
 166 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
 167 {
 168         __do_copy_to_user(to, from, n);
 169         return n;
 170 }
 171
 172 static __inline__ unsigned long clear_user (void *to, unsigned long n)
 173 {
 174         if (access_ok(VERIFY_WRITE, to, n))
 175                 __do_clear_user(to, n);
 176         return n;
 177 }
 178
 179 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
 180 {
 181         __do_clear_user(to, n);
 182         return n;
 183 }
 184
 185 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
 186 {
 187         long res = -EFAULT;
 188         if (access_ok(VERIFY_READ, src, 1))
 189                 __do_strncpy_from_user(dst, src, count, res);
 190         return res;
 191 }
 192
 193 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
 194 {
 195         long res;
 196         __do_strncpy_from_user(dst, src, count, res);
 197         return res;
 198 }
 199
 200 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 201
 202 static inline long strnlen_user(const char *s, long n)
 203 {
 204         unsigned long res = 0;
 205
 206         if (__addr_ok(s))
 207                 __do_strnlen_user(s, n, res);
 208
 209         return res;
 210 }
 211
 212 /*
 213  * These are the work horses of the get/put_user functions
 214  */
 215 #if 0
 216 #define __get_user_check(x,ptr,size)                                    \
 217 ({                                                                      \
 218         long __gu_err = -EFAULT, __gu_val = 0;                          \
 219         const __typeof__(*(ptr)) *__gu_addr = (ptr);                    \
 220         if (access_ok(VERIFY_READ,__gu_addr,size)) {                    \
 221                 __gu_err = 0;                                           \
 222                 __get_user_size(__gu_val,__gu_addr,(size),__gu_err);    \
 223         }                                                               \
 224         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 225         __gu_err;                                                       \
 226 })
 227 #endif
 228
 229 #define __get_user_nocheck(x,ptr,size)                                  \
 230 ({                                                                      \
 231         long __gu_err = 0, __gu_val;                                    \
 232         __get_user_size(__gu_val,(ptr),(size),__gu_err);                \
 233         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 234         __gu_err;                                                       \
 235 })
 236
 237 #define __get_user_nocheck_error(x,ptr,size,err)                        \
 238 ({                                                                      \
 239         long __gu_val;                                                  \
 240         __get_user_size(__gu_val,(ptr),(size),(err));                   \
 241         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 242         (void) 0;                                                       \
 243 })
 244
 245 #define __put_user_check(x,ptr,size)                                    \
 246 ({                                                                      \
 247         long __pu_err = -EFAULT;                                        \
 248         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 249         if (access_ok(VERIFY_WRITE,__pu_addr,size)) {                   \
 250                 __pu_err = 0;                                           \
 251                 __put_user_size((x),__pu_addr,(size),__pu_err);         \
 252         }                                                               \
 253         __pu_err;                                                       \
 254 })
 255
 256 #define __put_user_nocheck(x,ptr,size)                                  \
 257 ({                                                                      \
 258         long __pu_err = 0;                                              \
 259         __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 260         __put_user_size((x),__pu_addr,(size),__pu_err);                 \
 261         __pu_err;                                                       \
 262 })
 263
 264 #define __put_user_nocheck_error(x,ptr,size,err)                        \
 265 ({                                                                      \
 266         __put_user_size((x),(ptr),(size),err);                          \
 267         (void) 0;                                                       \
 268 })
 269
 270 #define __get_user_size(x,ptr,size,retval)                              \
 271 do {                                                                    \
 272         switch (size) {                                                 \
 273         case 1: __get_user_asm_byte(x,ptr,retval);      break;          \
 274         case 2: __get_user_asm_half(x,ptr,retval);      break;          \
 275         case 4: __get_user_asm_word(x,ptr,retval);      break;          \
 276         default: (x) = __get_user_bad();                                \
 277         }                                                               \
 278 } while (0)
 279
 280 #define __put_user_size(x,ptr,size,retval)                              \
 281 do {                                                                    \
 282         switch (size) {                                                 \
 283         case 1: __put_user_asm_byte(x,ptr,retval);      break;          \
 284         case 2: __put_user_asm_half(x,ptr,retval);      break;          \
 285         case 4: __put_user_asm_word(x,ptr,retval);      break;          \
 286         default: __put_user_bad();                                      \
 287         }                                                               \
 288 } while (0)
 289
 290 #endif /* _ASMARM_UACCESS_H */