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 /*
  44  * Single-value transfer routines.  They automatically use the right
  45  * size if we just have the right pointer type.  Note that the functions
  46  * which read from user space (*get_*) need to take care not to leak
  47  * kernel data even if the calling code is buggy and fails to check
  48  * the return value.  This means zeroing out the destination variable
  49  * or buffer on error.  Normally this is done out of line by the
  50  * fixup code, but there are a few places where it intrudes on the
  51  * main code path.  When we only write to user space, there is no
  52  * problem.
  53  *
  54  * The "__xxx" versions of the user access functions do not verify the
  55  * address space - it must have been done previously with a separate
  56  * "access_ok()" call.
  57  *
  58  * The "xxx_error" versions set the third argument to EFAULT if an
  59  * error occurs, and leave it unchanged on success.  Note that these
  60  * versions are void (ie, don't return a value as such).
  61  */
  62
  63 extern int __get_user_1(void *);
  64 extern int __get_user_2(void *);
  65 extern int __get_user_4(void *);
  66 extern int __get_user_8(void *);
  67 extern int __get_user_bad(void);
  68
  69 #define __get_user_x(__r1,__p,__e,__s,__i...)                           \
  70            __asm__ __volatile__ ("bl    __get_user_" #__s               \
  71                 : "=&r" (__e), "=r" (__r1)                              \
  72                 : "0" (__p)                                             \
  73                 : __i)
  74
  75 #define get_user(x,p)                                                   \
  76         ({                                                              \
  77                 const register typeof(*(p)) *__p asm("r0") = (p);       \
  78                 register typeof(*(p)) __r1 asm("r1");                   \
  79                 register int __e asm("r0");                             \
  80                 switch (sizeof(*(p))) {                                 \
  81                 case 1:                                                 \
  82                         __get_user_x(__r1, __p, __e, 1, "lr");          \
  83                         break;                                          \
  84                 case 2:                                                 \
  85                         __get_user_x(__r1, __p, __e, 2, "r2", "lr");    \
  86                         break;                                          \
  87                 case 4:                                                 \
  88                         __get_user_x(__r1, __p, __e, 4, "lr");          \
  89                         break;                                          \
  90                 case 8:                                                 \
  91                         __get_user_x(__r1, __p, __e, 8, "lr");          \
  92                         break;                                          \
  93                 default: __e = __get_user_bad(); break;                 \
  94                 }                                                       \
  95                 x = __r1;                                               \
  96                 __e;                                                    \
  97         })
  98
  99
 100 #define __get_user(x,ptr)                                               \
 101 ({                                                                      \
 102         long __gu_err = 0;                                              \
 103         __get_user_err((x),(ptr),__gu_err);                             \
 104         __gu_err;                                                       \
 105 })
 106
 107 #define __get_user_error(x,ptr,err)                                     \
 108 ({                                                                      \
 109         __get_user_err((x),(ptr),err);                                  \
 110         (void) 0;                                                       \
 111 })
 112
 113 #define __get_user_err(x,ptr,err)                                       \
 114 do {                                                                    \
 115         unsigned long __gu_addr = (unsigned long)(ptr);                 \
 116         unsigned long __gu_val;                                         \
 117         switch (sizeof(*(ptr))) {                                       \
 118         case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
 119         case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
 120         case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
 121         default: (__gu_val) = __get_user_bad();                         \
 122         }                                                               \
 123         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 124 } while (0)
 125
 126 extern int __put_user_1(void *, unsigned int);
 127 extern int __put_user_2(void *, unsigned int);
 128 extern int __put_user_4(void *, unsigned int);
 129 extern int __put_user_8(void *, unsigned long long);
 130 extern int __put_user_bad(void);
 131
 132 #define __put_user_x(__r1,__p,__e,__s)                                  \
 133            __asm__ __volatile__ (                                       \
 134                 __asmeq("%0", "r0") __asmeq("%2", "r1")                 \
 135                 "bl     __put_user_" #__s                               \
 136                 : "=&r" (__e)                                           \
 137                 : "0" (__p), "r" (__r1)                                 \
 138                 : "ip", "lr", "cc")
 139
 140 #define put_user(x,p)                                                   \
 141         ({                                                              \
 142                 const register typeof(*(p)) __r1 asm("r1") = (x);       \
 143                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 144                 register int __e asm("r0");                             \
 145                 switch (sizeof(*(__p))) {                               \
 146                 case 1:                                                 \
 147                         __put_user_x(__r1, __p, __e, 1);                \
 148                         break;                                          \
 149                 case 2:                                                 \
 150                         __put_user_x(__r1, __p, __e, 2);                \
 151                         break;                                          \
 152                 case 4:                                                 \
 153                         __put_user_x(__r1, __p, __e, 4);                \
 154                         break;                                          \
 155                 case 8:                                                 \
 156                         __put_user_x(__r1, __p, __e, 8);                \
 157                         break;                                          \
 158                 default: __e = __put_user_bad(); break;                 \
 159                 }                                                       \
 160                 __e;                                                    \
 161         })
 162
 163 #if 0
 164 /*********************   OLD METHOD *******************/
 165 #define __put_user_x(__r1,__p,__e,__s,__i...)                           \
 166            __asm__ __volatile__ ("bl    __put_user_" #__s               \
 167                 : "=&r" (__e)                                           \
 168                 : "0" (__p), "r" (__r1)                                 \
 169                 : __i)
 170
 171 #define put_user(x,p)                                                   \
 172         ({                                                              \
 173                 const register typeof(*(p)) __r1 asm("r1") = (x);       \
 174                 const register typeof(*(p)) *__p asm("r0") = (p);       \
 175                 register int __e asm("r0");                             \
 176                 switch (sizeof(*(p))) {                                 \
 177                 case 1:                                                 \
 178                         __put_user_x(__r1, __p, __e, 1, "r2", "lr");    \
 179                         break;                                          \
 180                 case 2:                                                 \
 181                         __put_user_x(__r1, __p, __e, 2, "r2", "lr");    \
 182                         break;                                          \
 183                 case 4:                                                 \
 184                         __put_user_x(__r1, __p, __e, 4, "r2", "lr");    \
 185                         break;                                          \
 186                 case 8:                                                 \
 187                         __put_user_x(__r1, __p, __e, 8, "r2", "ip", "lr");      \
 188                         break;                                          \
 189                 default: __e = __put_user_bad(); break;                 \
 190                 }                                                       \
 191                 __e;                                                    \
 192         })
 193 /*************************************************/
 194 #endif
 195
 196 #define __put_user(x,ptr)                                               \
 197 ({                                                                      \
 198         long __pu_err = 0;                                              \
 199         __put_user_err((x),(ptr),__pu_err);                             \
 200         __pu_err;                                                       \
 201 })
 202
 203 #define __put_user_error(x,ptr,err)                                     \
 204 ({                                                                      \
 205         __put_user_err((x),(ptr),err);                                  \
 206         (void) 0;                                                       \
 207 })
 208
 209 #define __put_user_err(x,ptr,err)                                       \
 210 do {                                                                    \
 211         unsigned long __pu_addr = (unsigned long)(ptr);                 \
 212         __typeof__(*(ptr)) __pu_val = (x);                              \
 213         switch (sizeof(*(ptr))) {                                       \
 214         case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
 215         case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
 216         case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
 217         case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
 218         default: __put_user_bad();                                      \
 219         }                                                               \
 220 } while (0)
 221
 222 static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
 223 {
 224         if (access_ok(VERIFY_READ, from, n))
 225                 __do_copy_from_user(to, from, n);
 226         else /* security hole - plug it */
 227                 memzero(to, n);
 228         return n;
 229 }
 230
 231 static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
 232 {
 233         __do_copy_from_user(to, from, n);
 234         return n;
 235 }
 236
 237 static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
 238 {
 239         if (access_ok(VERIFY_WRITE, to, n))
 240                 __do_copy_to_user(to, from, n);
 241         return n;
 242 }
 243
 244 static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
 245 {
 246         __do_copy_to_user(to, from, n);
 247         return n;
 248 }
 249
 250 #define __copy_to_user_inatomic __copy_to_user
 251 #define __copy_from_user_inatomic __copy_from_user
 252
 253 static __inline__ unsigned long clear_user (void *to, unsigned long n)
 254 {
 255         if (access_ok(VERIFY_WRITE, to, n))
 256                 __do_clear_user(to, n);
 257         return n;
 258 }
 259
 260 static __inline__ unsigned long __clear_user (void *to, unsigned long n)
 261 {
 262         __do_clear_user(to, n);
 263         return n;
 264 }
 265
 266 static __inline__ long strncpy_from_user (char *dst, const char *src, long count)
 267 {
 268         long res = -EFAULT;
 269         if (access_ok(VERIFY_READ, src, 1))
 270                 __do_strncpy_from_user(dst, src, count, res);
 271         return res;
 272 }
 273
 274 static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
 275 {
 276         long res;
 277         __do_strncpy_from_user(dst, src, count, res);
 278         return res;
 279 }
 280
 281 #define strlen_user(s)  strnlen_user(s, ~0UL >> 1)
 282
 283 static inline long strnlen_user(const char *s, long n)
 284 {
 285         unsigned long res = 0;
 286
 287         if (__addr_ok(s))
 288                 __do_strnlen_user(s, n, res);
 289
 290         return res;
 291 }
 292
 293 #endif /* _ASMARM_UACCESS_H */