include/asm-ppc/uaccess.h

   1 #ifdef __KERNEL__
   2 #ifndef _PPC_UACCESS_H
   3 #define _PPC_UACCESS_H
   4
   5 #ifndef __ASSEMBLY__
   6 #include <linux/sched.h>
   7 #include <linux/errno.h>
   8 #include <asm/processor.h>
   9
  10 #define VERIFY_READ     0
  11 #define VERIFY_WRITE    1
  12
  13 /*
  14  * The fs value determines whether argument validity checking should be
  15  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  16  * get_fs() == KERNEL_DS, checking is bypassed.
  17  *
  18  * For historical reasons, these macros are grossly misnamed.
  19  *
  20  * The fs/ds values are now the highest legal address in the "segment".
  21  * This simplifies the checking in the routines below.
  22  */
  23
  24 #define KERNEL_DS       ((mm_segment_t) { ~0UL })
  25 #define USER_DS         ((mm_segment_t) { TASK_SIZE - 1 })
  26
  27 #define get_ds()        (KERNEL_DS)
  28 #define get_fs()        (current->thread.fs)
  29 #define set_fs(val)     (current->thread.fs = (val))
  30
  31 #define segment_eq(a,b) ((a).seg == (b).seg)
  32
  33 #define __access_ok(addr,size)                                              \
  34         ((addr) <= current->thread.fs.seg                                   \
  35          && ((size) == 0 || (size) - 1 <= current->thread.fs.seg - (addr)))
  36
  37 #define access_ok(type, addr, size) \
  38         (__chk_user_ptr(addr),__access_ok((unsigned long)(addr),(size)))
  39
  40 extern inline int verify_area(int type, const void __user * addr, unsigned long size)
  41 {
  42         return access_ok(type, addr, size) ? 0 : -EFAULT;
  43 }
  44
  45
  46 /*
  47  * The exception table consists of pairs of addresses: the first is the
  48  * address of an instruction that is allowed to fault, and the second is
  49  * the address at which the program should continue.  No registers are
  50  * modified, so it is entirely up to the continuation code to figure out
  51  * what to do.
  52  *
  53  * All the routines below use bits of fixup code that are out of line
  54  * with the main instruction path.  This means when everything is well,
  55  * we don't even have to jump over them.  Further, they do not intrude
  56  * on our cache or tlb entries.
  57  */
  58
  59 struct exception_table_entry
  60 {
  61         unsigned long insn, fixup;
  62 };
  63
  64 /*
  65  * These are the main single-value transfer routines.  They automatically
  66  * use the right size if we just have the right pointer type.
  67  *
  68  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  69  * and yet we don't want to do any pointers, because that is too much
  70  * of a performance impact. Thus we have a few rather ugly macros here,
  71  * and hide all the ugliness from the user.
  72  *
  73  * The "__xxx" versions of the user access functions are versions that
  74  * do not verify the address space, that must have been done previously
  75  * with a separate "access_ok()" call (this is used when we do multiple
  76  * accesses to the same area of user memory).
  77  *
  78  * As we use the same address space for kernel and user data on the
  79  * PowerPC, we can just do these as direct assignments.  (Of course, the
  80  * exception handling means that it's no longer "just"...)
  81  *
  82  * The "user64" versions of the user access functions are versions that
  83  * allow access of 64-bit data. The "get_user" functions do not
  84  * properly handle 64-bit data because the value gets down cast to a long.
  85  * The "put_user" functions already handle 64-bit data properly but we add
  86  * "user64" versions for completeness
  87  */
  88 #define get_user(x,ptr) \
  89   __get_user_check((x),(ptr),sizeof(*(ptr)))
  90 #define get_user64(x,ptr) \
  91   __get_user64_check((x),(ptr),sizeof(*(ptr)))
  92 #define put_user(x,ptr) \
  93   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  94 #define put_user64(x,ptr) put_user(x,ptr)
  95
  96 #define __get_user(x,ptr) \
  97   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  98 #define __get_user64(x,ptr) \
  99   __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
 100 #define __put_user(x,ptr) \
 101   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 102 #define __put_user64(x,ptr) __put_user(x,ptr)
 103
 104 extern long __put_user_bad(void);
 105
 106 #define __put_user_nocheck(x,ptr,size)                  \
 107 ({                                                      \
 108         long __pu_err;                                  \
 109         __chk_user_ptr(ptr);                            \
 110         __put_user_size((x),(ptr),(size),__pu_err);     \
 111         __pu_err;                                       \
 112 })
 113
 114 #define __put_user_check(x,ptr,size)                            \
 115 ({                                                              \
 116         long __pu_err = -EFAULT;                                \
 117         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 118         if (access_ok(VERIFY_WRITE,__pu_addr,size))             \
 119                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 120         __pu_err;                                               \
 121 })
 122
 123 #define __put_user_size(x,ptr,size,retval)              \
 124 do {                                                    \
 125         retval = 0;                                     \
 126         switch (size) {                                 \
 127         case 1:                                         \
 128                 __put_user_asm(x, ptr, retval, "stb");  \
 129                 break;                                  \
 130         case 2:                                         \
 131                 __put_user_asm(x, ptr, retval, "sth");  \
 132                 break;                                  \
 133         case 4:                                         \
 134                 __put_user_asm(x, ptr, retval, "stw");  \
 135                 break;                                  \
 136         case 8:                                         \
 137                 __put_user_asm2(x, ptr, retval);        \
 138                 break;                                  \
 139         default:                                        \
 140                 __put_user_bad();                       \
 141         }                                               \
 142 } while (0)
 143
 144 /*
 145  * We don't tell gcc that we are accessing memory, but this is OK
 146  * because we do not write to any memory gcc knows about, so there
 147  * are no aliasing issues.
 148  */
 149 #define __put_user_asm(x, addr, err, op)                        \
 150         __asm__ __volatile__(                                   \
 151                 "1:     "op" %1,0(%2)\n"                        \
 152                 "2:\n"                                          \
 153                 ".section .fixup,\"ax\"\n"                      \
 154                 "3:     li %0,%3\n"                             \
 155                 "       b 2b\n"                                 \
 156                 ".previous\n"                                   \
 157                 ".section __ex_table,\"a\"\n"                   \
 158                 "       .align 2\n"                             \
 159                 "       .long 1b,3b\n"                          \
 160                 ".previous"                                     \
 161                 : "=r" (err)                                    \
 162                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 163
 164 #define __put_user_asm2(x, addr, err)                           \
 165         __asm__ __volatile__(                                   \
 166                 "1:     stw %1,0(%2)\n"                         \
 167                 "2:     stw %1+1,4(%2)\n"                       \
 168                 "3:\n"                                          \
 169                 ".section .fixup,\"ax\"\n"                      \
 170                 "4:     li %0,%3\n"                             \
 171                 "       b 3b\n"                                 \
 172                 ".previous\n"                                   \
 173                 ".section __ex_table,\"a\"\n"                   \
 174                 "       .align 2\n"                             \
 175                 "       .long 1b,4b\n"                          \
 176                 "       .long 2b,4b\n"                          \
 177                 ".previous"                                     \
 178                 : "=r" (err)                                    \
 179                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 180
 181 #define __get_user_nocheck(x, ptr, size)                        \
 182 ({                                                              \
 183         long __gu_err;                                          \
 184         unsigned long __gu_val;                                 \
 185         __chk_user_ptr(ptr);                                    \
 186         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 187         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 188         __gu_err;                                               \
 189 })
 190
 191 #define __get_user64_nocheck(x, ptr, size)                      \
 192 ({                                                              \
 193         long __gu_err;                                          \
 194         long long __gu_val;                                     \
 195         __chk_user_ptr(ptr);                                    \
 196         __get_user_size64(__gu_val, (ptr), (size), __gu_err);   \
 197         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 198         __gu_err;                                               \
 199 })
 200
 201 #define __get_user_check(x, ptr, size)                                  \
 202 ({                                                                      \
 203         long __gu_err = -EFAULT;                                        \
 204         unsigned long  __gu_val = 0;                                    \
 205         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 206         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 207                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 208         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 209         __gu_err;                                                       \
 210 })
 211
 212 #define __get_user64_check(x, ptr, size)                                  \
 213 ({                                                                        \
 214         long __gu_err = -EFAULT;                                          \
 215         long long __gu_val = 0;                                           \
 216         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);               \
 217         if (access_ok(VERIFY_READ, __gu_addr, (size)))                    \
 218                 __get_user_size64(__gu_val, __gu_addr, (size), __gu_err); \
 219         (x) = (__typeof__(*(ptr)))__gu_val;                               \
 220         __gu_err;                                                         \
 221 })
 222
 223 extern long __get_user_bad(void);
 224
 225 #define __get_user_size(x, ptr, size, retval)                   \
 226 do {                                                            \
 227         retval = 0;                                             \
 228         switch (size) {                                         \
 229         case 1:                                                 \
 230                 __get_user_asm(x, ptr, retval, "lbz");          \
 231                 break;                                          \
 232         case 2:                                                 \
 233                 __get_user_asm(x, ptr, retval, "lhz");          \
 234                 break;                                          \
 235         case 4:                                                 \
 236                 __get_user_asm(x, ptr, retval, "lwz");          \
 237                 break;                                          \
 238         default:                                                \
 239                 x = __get_user_bad();                           \
 240         }                                                       \
 241 } while (0)
 242
 243 #define __get_user_size64(x, ptr, size, retval)                 \
 244 do {                                                            \
 245         retval = 0;                                             \
 246         switch (size) {                                         \
 247         case 1:                                                 \
 248                 __get_user_asm(x, ptr, retval, "lbz");          \
 249                 break;                                          \
 250         case 2:                                                 \
 251                 __get_user_asm(x, ptr, retval, "lhz");          \
 252                 break;                                          \
 253         case 4:                                                 \
 254                 __get_user_asm(x, ptr, retval, "lwz");          \
 255                 break;                                          \
 256         case 8:                                                 \
 257                 __get_user_asm2(x, ptr, retval);                \
 258                 break;                                          \
 259         default:                                                \
 260                 x = __get_user_bad();                           \
 261         }                                                       \
 262 } while (0)
 263
 264 #define __get_user_asm(x, addr, err, op)                \
 265         __asm__ __volatile__(                           \
 266                 "1:     "op" %1,0(%2)\n"                \
 267                 "2:\n"                                  \
 268                 ".section .fixup,\"ax\"\n"              \
 269                 "3:     li %0,%3\n"                     \
 270                 "       li %1,0\n"                      \
 271                 "       b 2b\n"                         \
 272                 ".previous\n"                           \
 273                 ".section __ex_table,\"a\"\n"           \
 274                 "       .align 2\n"                     \
 275                 "       .long 1b,3b\n"                  \
 276                 ".previous"                             \
 277                 : "=r"(err), "=r"(x)                    \
 278                 : "b"(addr), "i"(-EFAULT), "0"(err))
 279
 280 #define __get_user_asm2(x, addr, err)                   \
 281         __asm__ __volatile__(                           \
 282                 "1:     lwz %1,0(%2)\n"                 \
 283                 "2:     lwz %1+1,4(%2)\n"               \
 284                 "3:\n"                                  \
 285                 ".section .fixup,\"ax\"\n"              \
 286                 "4:     li %0,%3\n"                     \
 287                 "       li %1,0\n"                      \
 288                 "       li %1+1,0\n"                    \
 289                 "       b 3b\n"                         \
 290                 ".previous\n"                           \
 291                 ".section __ex_table,\"a\"\n"           \
 292                 "       .align 2\n"                     \
 293                 "       .long 1b,4b\n"                  \
 294                 "       .long 2b,4b\n"                  \
 295                 ".previous"                             \
 296                 : "=r"(err), "=&r"(x)                   \
 297                 : "b"(addr), "i"(-EFAULT), "0"(err))
 298
 299 /* more complex routines */
 300
 301 extern int __copy_tofrom_user(void __user *to, const void __user *from,
 302                               unsigned long size);
 303
 304 extern inline unsigned long
 305 copy_from_user(void *to, const void __user *from, unsigned long n)
 306 {
 307         unsigned long over;
 308
 309         if (access_ok(VERIFY_READ, from, n))
 310                 return __copy_tofrom_user((__force void __user *)to, from, n);
 311         if ((unsigned long)from < TASK_SIZE) {
 312                 over = (unsigned long)from + n - TASK_SIZE;
 313                 return __copy_tofrom_user((__force void __user *)to, from, n - over) + over;
 314         }
 315         return n;
 316 }
 317
 318 extern inline unsigned long
 319 copy_to_user(void __user *to, const void *from, unsigned long n)
 320 {
 321         unsigned long over;
 322
 323         if (access_ok(VERIFY_WRITE, to, n))
 324                 return __copy_tofrom_user(to, (__force void __user *) from, n);
 325         if ((unsigned long)to < TASK_SIZE) {
 326                 over = (unsigned long)to + n - TASK_SIZE;
 327                 return __copy_tofrom_user(to, (__force void __user *) from, n - over) + over;
 328         }
 329         return n;
 330 }
 331
 332 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long size)
 333 {
 334         return __copy_tofrom_user((__force void __user *)to, from, size);
 335 }
 336
 337 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long size)
 338 {
 339         return __copy_tofrom_user(to, (__force void __user *)from, size);
 340 }
 341
 342 #define __copy_to_user_inatomic __copy_to_user
 343 #define __copy_from_user_inatomic __copy_from_user
 344
 345 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 346
 347 extern inline unsigned long
 348 clear_user(void __user *addr, unsigned long size)
 349 {
 350         if (access_ok(VERIFY_WRITE, addr, size))
 351                 return __clear_user(addr, size);
 352         if ((unsigned long)addr < TASK_SIZE) {
 353                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 354                 return __clear_user(addr, size - over) + over;
 355         }
 356         return size;
 357 }
 358
 359 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 360
 361 extern inline long
 362 strncpy_from_user(char *dst, const char __user *src, long count)
 363 {
 364         if (access_ok(VERIFY_READ, src, 1))
 365                 return __strncpy_from_user(dst, src, count);
 366         return -EFAULT;
 367 }
 368
 369 /*
 370  * Return the size of a string (including the ending 0)
 371  *
 372  * Return 0 for error
 373  */
 374
 375 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 376
 377 /*
 378  * Returns the length of the string at str (including the null byte),
 379  * or 0 if we hit a page we can't access,
 380  * or something > len if we didn't find a null byte.
 381  *
 382  * The `top' parameter to __strnlen_user is to make sure that
 383  * we can never overflow from the user area into kernel space.
 384  */
 385 extern __inline__ int strnlen_user(const char __user *str, long len)
 386 {
 387         unsigned long top = current->thread.fs.seg;
 388
 389         if ((unsigned long)str > top)
 390                 return 0;
 391         return __strnlen_user(str, len, top);
 392 }
 393
 394 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 395
 396 #endif  /* __ASSEMBLY__ */
 397
 398 #endif  /* _PPC_UACCESS_H */
 399 #endif /* __KERNEL__ */