include/asm-arm26/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 extern int fixup_exception(struct pt_regs *regs);
  34
  35 #define get_ds()        (KERNEL_DS)
  36 #define get_fs()        (current_thread_info()->addr_limit)
  37 #define segment_eq(a,b) ((a) == (b))
  38
  39 #include <asm/uaccess-asm.h>
  40
  41 #define access_ok(type,addr,size)       (__range_ok(addr,size) == 0)
  42
  43 static inline int verify_area(int type, const void * addr, unsigned long size)
  44 {
  45         return access_ok(type, addr, size) ? 0 : -EFAULT;
  46 }
  47
  48 /*
  49  * Single-value transfer routines.  They automatically use the right
  50  * size if we just have the right pointer type.  Note that the functions
  51  * which read from user space (*get_*) need to take care not to leak
  52  * kernel data even if the calling code is buggy and fails to check
  53  * the return value.  This means zeroing out the destination variable
  54  * or buffer on error.  Normally this is done out of line by the
  55  * fixup code, but there are a few places where it intrudes on the
  56  * main code path.  When we only write to user space, there is no
  57  * problem.
  58  *
  59  * The "__xxx" versions of the user access functions do not verify the
  60  * address space - it must have been done previously with a separate
  61  * "access_ok()" call.
  62  *
  63  * The "xxx_error" versions set the third argument to EFAULT if an
  64  * error occurs, and leave it unchanged on success.  Note that these
  65  * versions are void (ie, don't return a value as such).
  66  */
  67
  68 extern int __get_user_1(void *);
  69 extern int __get_user_2(void *);
  70 extern int __get_user_4(void *);
  71 extern int __get_user_8(void *);
  72 extern int __get_user_bad(void);
  73
  74 #define __get_user_x(__r1,__p,__e,__s,__i...)                           \
  75            __asm__ __volatile__ ("bl    __get_user_" #__s               \
  76                 : "=&r" (__e), "=r" (__r1)                              \
  77                 : "0" (__p)                                             \
  78                 : __i)
  79
  80 #define get_user(x,p)                                                   \
  81         ({                                                              \
  82                 const register typeof(*(p)) *__p asm("r0") = (p);       \
  83                 register typeof(*(p)) __r1 asm("r1");                   \
  84                 register int __e asm("r0");                             \
  85                 switch (sizeof(*(p))) {                                 \
  86                 case 1:                                                 \
  87                         __get_user_x(__r1, __p, __e, 1, "lr");          \
  88                         break;                                          \
  89                 case 2:                                                 \
  90                         __get_user_x(__r1, __p, __e, 2, "r2", "lr");    \
  91                         break;                                          \
  92                 case 4:                                                 \
  93                         __get_user_x(__r1, __p, __e, 4, "lr");          \
  94                         break;                                          \
  95                 case 8:                                                 \
  96                         __get_user_x(__r1, __p, __e, 8, "lr");          \
  97                         break;                                          \
  98                 default: __e = __get_user_bad(); break;                 \
  99                 }                                                       \
 100                 x = __r1;                                               \
 101                 __e;                                                    \
 102         })
 103
 104
 105 #define __get_user(x,ptr)                                               \
 106 ({                                                                      \
 107         long __gu_err = 0;                                              \
 108         __get_user_err((x),(ptr),__gu_err);                             \
 109         __gu_err;                                                       \
 110 })
 111
 112 #define __get_user_error(x,ptr,err)                                     \
 113 ({                                                                      \
 114         __get_user_err((x),(ptr),err);                                  \
 115         (void) 0;                                                       \
 116 })
 117
 118 #define __get_user_err(x,ptr,err)                                       \
 119 do {                                                                    \
 120         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 121         unsigned long __gu_val;                                         \
 122         switch (sizeof(*(ptr))) {                                       \
 123         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 124         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 125         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 126         default: (__gu_val) = __get_user_bad();                         \
 127         }                                                               \
 128         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 129 } while (0)
 130
 131 extern int __put_user_1(void *, unsigned int);
 132 extern int __put_user_2(void *, unsigned int);
 133 extern int __put_user_4(void *, unsigned int);
 134 extern int __put_user_8(void *, unsigned long long);
 135 extern int __put_user_bad(void);
 136
 137 #define __put_user_x(__r1,__p,__e,__s,__i...)                           \
 138            __asm__ __volatile__ ("bl    __put_user_" #__s               \
 139                 : "=&r" (__e)                                           \
 140                 : "0" (__p), "r" (__r1)                                 \
 141                 : __i)
 142
 143 #define put_user(x,p)                                                   \
 144         ({                                                              \
 145                 const register typeof(*(p)) __r1 asm("r1") = (x);       \
 146                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 147                 register int __e asm("r0");                             \
 148                 switch (sizeof(*(p))) {                                 \
 149                 case 1:                                                 \
 150                         __put_user_x(__r1, __p, __e, 1, "r2", "lr");    \
 151                         break;                                          \
 152                 case 2:                                                 \
 153                         __put_user_x(__r1, __p, __e, 2, "r2", "lr");    \
 154                         break;                                          \
 155                 case 4:                                                 \
 156                         __put_user_x(__r1, __p, __e, 4, "r2", "lr");    \
 157                         break;                                          \
 158                 case 8:                                                 \
 159                         __put_user_x(__r1, __p, __e, 8, "ip", "lr");    \
 160                         break;                                          \
 161                 default: __e = __put_user_bad(); break;                 \
 162                 }                                                       \
 163                 __e;                                                    \
 164         })
 165
 166 #define __put_user(x,ptr)                                               \
 167 ({                                                                      \
 168         long __pu_err = 0;                                              \
 169         __put_user_err((x),(ptr),__pu_err);                             \
 170         __pu_err;                                                       \
 171 })
 172
 173 #define __put_user_error(x,ptr,err)                                     \
 174 ({                                                                      \
 175         __put_user_err((x),(ptr),err);                                  \
 176         (void) 0;                                                       \
 177 })
 178
 179 #define __put_user_err(x,ptr,err)                                       \
 180 do {                                                                    \
 181         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 182         __typeof__(*(ptr)) __pu_val = (x);                              \
 183         switch (sizeof(*(ptr))) {                                       \
 184         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 185         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 186         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 187         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 188         default: __put_user_bad();                                      \
 189         }                                                               \
 190 } while (0)
 191
 192 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
 193 {
 194         if (access_ok(VERIFY_READ, from, n))
 195                 __do_copy_from_user(to, from, n);
 196         else /* security hole - plug it */
 197                 memzero(to, n);
 198         return n;
 199 }
 200
 201 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
 202 {
 203         __do_copy_from_user(to, from, n);
 204         return n;
 205 }
 206
 207 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
 208 {
 209         if (access_ok(VERIFY_WRITE, to, n))
 210                 __do_copy_to_user(to, from, n);
 211         return n;
 212 }
 213
 214 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
 215 {
 216         __do_copy_to_user(to, from, n);
 217         return n;
 218 }
 219
 220 static __inline__ unsigned long clear_user (void *to, unsigned long n)
 221 {
 222         if (access_ok(VERIFY_WRITE, to, n))
 223                 __do_clear_user(to, n);
 224         return n;
 225 }
 226
 227 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
 228 {
 229         __do_clear_user(to, n);
 230         return n;
 231 }
 232
 233 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
 234 {
 235         long res = -EFAULT;
 236         if (access_ok(VERIFY_READ, src, 1))
 237                 __do_strncpy_from_user(dst, src, count, res);
 238         return res;
 239 }
 240
 241 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
 242 {
 243         long res;
 244         __do_strncpy_from_user(dst, src, count, res);
 245         return res;
 246 }
 247
 248 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 249
 250 static inline long strnlen_user(const char *s, long n)
 251 {
 252         unsigned long res = 0;
 253
 254         if (__addr_ok(s))
 255                 __do_strnlen_user(s, n, res);
 256
 257         return res;
 258 }
 259
 260 #endif /* _ASMARM_UACCESS_H */