include/asm-powerpc/uaccess.h

   1 #ifndef _ARCH_POWERPC_UACCESS_H
   2 #define _ARCH_POWERPC_UACCESS_H
   3
   4 #ifdef __KERNEL__
   5 #ifndef __ASSEMBLY__
   6
   7 #include <linux/sched.h>
   8 #include <linux/errno.h>
   9 #include <asm/processor.h>
  10
  11 #define VERIFY_READ     0
  12 #define VERIFY_WRITE    1
  13
  14 /*
  15  * The fs value determines whether argument validity checking should be
  16  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  17  * get_fs() == KERNEL_DS, checking is bypassed.
  18  *
  19  * For historical reasons, these macros are grossly misnamed.
  20  *
  21  * The fs/ds values are now the highest legal address in the "segment".
  22  * This simplifies the checking in the routines below.
  23  */
  24
  25 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  26
  27 #ifdef __powerpc64__
  28 #define KERNEL_DS       MAKE_MM_SEG(0UL)
  29 #define USER_DS         MAKE_MM_SEG(0xf000000000000000UL)
  30 #else
  31 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  32 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  33 #endif
  34
  35 #define get_ds()        (KERNEL_DS)
  36 #define get_fs()        (current->thread.fs)
  37 #define set_fs(val)     (current->thread.fs = (val))
  38
  39 #define segment_eq(a, b)        ((a).seg == (b).seg)
  40
  41 #ifdef __powerpc64__
  42 /*
  43  * Use the alpha trick for checking ranges:
  44  *
  45  * Is a address valid? This does a straightforward calculation rather
  46  * than tests.
  47  *
  48  * Address valid if:
  49  *  - "addr" doesn't have any high-bits set
  50  *  - AND "size" doesn't have any high-bits set
  51  *  - OR we are in kernel mode.
  52  *
  53  * We dont have to check for high bits in (addr+size) because the first
  54  * two checks force the maximum result to be below the start of the
  55  * kernel region.
  56  */
  57 #define __access_ok(addr, size, segment)        \
  58         (((segment).seg & (addr | size )) == 0)
  59
  60 #else
  61
  62 #define __access_ok(addr, size, segment)        \
  63         (((addr) <= (segment).seg) &&           \
  64          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  65
  66 #endif
  67
  68 #define access_ok(type, addr, size)             \
  69         (__chk_user_ptr(addr),                  \
  70          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  71
  72 /*
  73  * The exception table consists of pairs of addresses: the first is the
  74  * address of an instruction that is allowed to fault, and the second is
  75  * the address at which the program should continue.  No registers are
  76  * modified, so it is entirely up to the continuation code to figure out
  77  * what to do.
  78  *
  79  * All the routines below use bits of fixup code that are out of line
  80  * with the main instruction path.  This means when everything is well,
  81  * we don't even have to jump over them.  Further, they do not intrude
  82  * on our cache or tlb entries.
  83  */
  84
  85 struct exception_table_entry {
  86         unsigned long insn;
  87         unsigned long fixup;
  88 };
  89
  90 /*
  91  * These are the main single-value transfer routines.  They automatically
  92  * use the right size if we just have the right pointer type.
  93  *
  94  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  95  * and yet we don't want to do any pointers, because that is too much
  96  * of a performance impact. Thus we have a few rather ugly macros here,
  97  * and hide all the ugliness from the user.
  98  *
  99  * The "__xxx" versions of the user access functions are versions that
 100  * do not verify the address space, that must have been done previously
 101  * with a separate "access_ok()" call (this is used when we do multiple
 102  * accesses to the same area of user memory).
 103  *
 104  * As we use the same address space for kernel and user data on the
 105  * PowerPC, we can just do these as direct assignments.  (Of course, the
 106  * exception handling means that it's no longer "just"...)
 107  *
 108  * The "user64" versions of the user access functions are versions that
 109  * allow access of 64-bit data. The "get_user" functions do not
 110  * properly handle 64-bit data because the value gets down cast to a long.
 111  * The "put_user" functions already handle 64-bit data properly but we add
 112  * "user64" versions for completeness
 113  */
 114 #define get_user(x, ptr) \
 115         __get_user_check((x), (ptr), sizeof(*(ptr)))
 116 #define put_user(x, ptr) \
 117         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 118
 119 #define __get_user(x, ptr) \
 120         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 121 #define __put_user(x, ptr) \
 122         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 123 #ifndef __powerpc64__
 124 #define __get_user64(x, ptr) \
 125         __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
 126 #define __put_user64(x, ptr) __put_user(x, ptr)
 127 #endif
 128
 129 #ifdef __powerpc64__
 130 #define __get_user_unaligned __get_user
 131 #define __put_user_unaligned __put_user
 132 #endif
 133
 134 extern long __put_user_bad(void);
 135
 136 #ifdef __powerpc64__
 137 #define __EX_TABLE_ALIGN        "3"
 138 #define __EX_TABLE_TYPE         "llong"
 139 #else
 140 #define __EX_TABLE_ALIGN        "2"
 141 #define __EX_TABLE_TYPE         "long"
 142 #endif
 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) # put_user\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 " __EX_TABLE_ALIGN "\n"          \
 159                 "       ."__EX_TABLE_TYPE" 1b,3b\n"             \
 160                 ".previous"                                     \
 161                 : "=r" (err)                                    \
 162                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 163
 164 #ifndef __powerpc64__
 165 #define __put_user_asm2(x, addr, err)                           \
 166         __asm__ __volatile__(                                   \
 167                 "1:     stw %1,0(%2)\n"                         \
 168                 "2:     stw %1+1,4(%2)\n"                       \
 169                 "3:\n"                                          \
 170                 ".section .fixup,\"ax\"\n"                      \
 171                 "4:     li %0,%3\n"                             \
 172                 "       b 3b\n"                                 \
 173                 ".previous\n"                                   \
 174                 ".section __ex_table,\"a\"\n"                   \
 175                 "       .align " __EX_TABLE_ALIGN "\n"          \
 176                 "       ." __EX_TABLE_TYPE " 1b,4b\n"           \
 177                 "       ." __EX_TABLE_TYPE " 2b,4b\n"           \
 178                 ".previous"                                     \
 179                 : "=r" (err)                                    \
 180                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 181 #else /* __powerpc64__ */
 182 #define __put_user_asm2(x, ptr, retval)                         \
 183           __put_user_asm(x, ptr, retval, "std")
 184 #endif /* __powerpc64__ */
 185
 186 #define __put_user_size(x, ptr, size, retval)                   \
 187 do {                                                            \
 188         retval = 0;                                             \
 189         switch (size) {                                         \
 190           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 191           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 192           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 193           case 8: __put_user_asm2(x, ptr, retval); break;       \
 194           default: __put_user_bad();                            \
 195         }                                                       \
 196 } while (0)
 197
 198 #define __put_user_nocheck(x, ptr, size)                        \
 199 ({                                                              \
 200         long __pu_err;                                          \
 201         might_sleep();                                          \
 202         __chk_user_ptr(ptr);                                    \
 203         __put_user_size((x), (ptr), (size), __pu_err);          \
 204         __pu_err;                                               \
 205 })
 206
 207 #define __put_user_check(x, ptr, size)                                  \
 208 ({                                                                      \
 209         long __pu_err = -EFAULT;                                        \
 210         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 211         might_sleep();                                                  \
 212         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 213                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 214         __pu_err;                                                       \
 215 })
 216
 217 extern long __get_user_bad(void);
 218
 219 #define __get_user_asm(x, addr, err, op)                \
 220         __asm__ __volatile__(                           \
 221                 "1:     "op" %1,0(%2)   # get_user\n"   \
 222                 "2:\n"                                  \
 223                 ".section .fixup,\"ax\"\n"              \
 224                 "3:     li %0,%3\n"                     \
 225                 "       li %1,0\n"                      \
 226                 "       b 2b\n"                         \
 227                 ".previous\n"                           \
 228                 ".section __ex_table,\"a\"\n"           \
 229                 "       .align "__EX_TABLE_ALIGN "\n"   \
 230                 "       ." __EX_TABLE_TYPE " 1b,3b\n"   \
 231                 ".previous"                             \
 232                 : "=r" (err), "=r" (x)                  \
 233                 : "b" (addr), "i" (-EFAULT), "0" (err))
 234
 235 #ifndef __powerpc64__
 236 #define __get_user_asm2(x, addr, err)                   \
 237         __asm__ __volatile__(                           \
 238                 "1:     lwz %1,0(%2)\n"                 \
 239                 "2:     lwz %1+1,4(%2)\n"               \
 240                 "3:\n"                                  \
 241                 ".section .fixup,\"ax\"\n"              \
 242                 "4:     li %0,%3\n"                     \
 243                 "       li %1,0\n"                      \
 244                 "       li %1+1,0\n"                    \
 245                 "       b 3b\n"                         \
 246                 ".previous\n"                           \
 247                 ".section __ex_table,\"a\"\n"           \
 248                 "       .align " __EX_TABLE_ALIGN "\n"  \
 249                 "       ." __EX_TABLE_TYPE " 1b,4b\n"   \
 250                 "       ." __EX_TABLE_TYPE " 2b,4b\n"   \
 251                 ".previous"                             \
 252                 : "=r" (err), "=&r" (x)                 \
 253                 : "b" (addr), "i" (-EFAULT), "0" (err))
 254 #else
 255 #define __get_user_asm2(x, addr, err)                   \
 256         __get_user_asm(x, addr, err, "ld")
 257 #endif /* __powerpc64__ */
 258
 259 #define __get_user_size(x, ptr, size, retval)                   \
 260 do {                                                            \
 261         retval = 0;                                             \
 262         __chk_user_ptr(ptr);                                    \
 263         if (size > sizeof(x))                                   \
 264                 (x) = __get_user_bad();                         \
 265         switch (size) {                                         \
 266         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 267         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 268         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 269         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 270         default: (x) = __get_user_bad();                        \
 271         }                                                       \
 272 } while (0)
 273
 274 #define __get_user_nocheck(x, ptr, size)                        \
 275 ({                                                              \
 276         long __gu_err;                                          \
 277         unsigned long __gu_val;                                 \
 278         __chk_user_ptr(ptr);                                    \
 279         might_sleep();                                          \
 280         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 281         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 282         __gu_err;                                               \
 283 })
 284
 285 #ifndef __powerpc64__
 286 #define __get_user64_nocheck(x, ptr, size)                      \
 287 ({                                                              \
 288         long __gu_err;                                          \
 289         long long __gu_val;                                     \
 290         __chk_user_ptr(ptr);                                    \
 291         might_sleep();                                          \
 292         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 293         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 294         __gu_err;                                               \
 295 })
 296 #endif /* __powerpc64__ */
 297
 298 #define __get_user_check(x, ptr, size)                                  \
 299 ({                                                                      \
 300         long __gu_err = -EFAULT;                                        \
 301         unsigned long  __gu_val = 0;                                    \
 302         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 303         might_sleep();                                                  \
 304         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 305                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 306         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 307         __gu_err;                                                       \
 308 })
 309
 310 /* more complex routines */
 311
 312 extern unsigned long __copy_tofrom_user(void __user *to,
 313                 const void __user *from, unsigned long size);
 314
 315 #ifndef __powerpc64__
 316 extern inline unsigned long
 317 copy_from_user(void *to, const void __user *from, unsigned long n)
 318 {
 319         unsigned long over;
 320
 321         if (access_ok(VERIFY_READ, from, n))
 322                 return __copy_tofrom_user((__force void __user *)to, from, n);
 323         if ((unsigned long)from < TASK_SIZE) {
 324                 over = (unsigned long)from + n - TASK_SIZE;
 325                 return __copy_tofrom_user((__force void __user *)to, from,
 326                                 n - over) + over;
 327         }
 328         return n;
 329 }
 330
 331 extern inline unsigned long
 332 copy_to_user(void __user *to, const void *from, unsigned long n)
 333 {
 334         unsigned long over;
 335
 336         if (access_ok(VERIFY_WRITE, to, n))
 337                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 338         if ((unsigned long)to < TASK_SIZE) {
 339                 over = (unsigned long)to + n - TASK_SIZE;
 340                 return __copy_tofrom_user(to, (__force void __user *)from,
 341                                 n - over) + over;
 342         }
 343         return n;
 344 }
 345
 346 #else /* __powerpc64__ */
 347
 348 static inline unsigned long
 349 __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
 350 {
 351         if (__builtin_constant_p(n) && (n <= 8)) {
 352                 unsigned long ret;
 353
 354                 switch (n) {
 355                 case 1:
 356                         __get_user_size(*(u8 *)to, from, 1, ret);
 357                         break;
 358                 case 2:
 359                         __get_user_size(*(u16 *)to, from, 2, ret);
 360                         break;
 361                 case 4:
 362                         __get_user_size(*(u32 *)to, from, 4, ret);
 363                         break;
 364                 case 8:
 365                         __get_user_size(*(u64 *)to, from, 8, ret);
 366                         break;
 367                 }
 368                 return (ret == -EFAULT) ? n : 0;
 369         }
 370         return __copy_tofrom_user((__force void __user *) to, from, n);
 371 }
 372
 373 static inline unsigned long
 374 __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
 375 {
 376         if (__builtin_constant_p(n) && (n <= 8)) {
 377                 unsigned long ret;
 378
 379                 switch (n) {
 380                 case 1:
 381                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 382                         break;
 383                 case 2:
 384                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 385                         break;
 386                 case 4:
 387                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 388                         break;
 389                 case 8:
 390                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 391                         break;
 392                 }
 393                 return (ret == -EFAULT) ? n : 0;
 394         }
 395         return __copy_tofrom_user(to, (__force const void __user *) from, n);
 396 }
 397
 398 #endif /* __powerpc64__ */
 399
 400 static inline unsigned long
 401 __copy_from_user(void *to, const void __user *from, unsigned long size)
 402 {
 403         might_sleep();
 404 #ifndef __powerpc64__
 405         return __copy_tofrom_user((__force void __user *)to, from, size);
 406 #else /* __powerpc64__ */
 407         return __copy_from_user_inatomic(to, from, size);
 408 #endif /* __powerpc64__ */
 409 }
 410
 411 static inline unsigned long
 412 __copy_to_user(void __user *to, const void *from, unsigned long size)
 413 {
 414         might_sleep();
 415 #ifndef __powerpc64__
 416         return __copy_tofrom_user(to, (__force void __user *)from, size);
 417 #else /* __powerpc64__ */
 418         return __copy_to_user_inatomic(to, from, size);
 419 #endif /* __powerpc64__ */
 420 }
 421
 422 #ifndef __powerpc64__
 423 #define __copy_to_user_inatomic __copy_to_user
 424 #define __copy_from_user_inatomic __copy_from_user
 425 #else /* __powerpc64__ */
 426 #define __copy_in_user(to, from, size) \
 427         __copy_tofrom_user((to), (from), (size))
 428
 429 extern unsigned long copy_from_user(void *to, const void __user *from,
 430                                     unsigned long n);
 431 extern unsigned long copy_to_user(void __user *to, const void *from,
 432                                   unsigned long n);
 433 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 434                                   unsigned long n);
 435 #endif /* __powerpc64__ */
 436
 437 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 438
 439 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 440 {
 441         might_sleep();
 442         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 443                 return __clear_user(addr, size);
 444 #ifndef __powerpc64__
 445         if ((unsigned long)addr < TASK_SIZE) {
 446                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 447                 return __clear_user(addr, size - over) + over;
 448         }
 449 #endif /* __powerpc64__ */
 450         return size;
 451 }
 452
 453 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 454
 455 static inline long strncpy_from_user(char *dst, const char __user *src,
 456                 long count)
 457 {
 458         might_sleep();
 459         if (likely(access_ok(VERIFY_READ, src, 1)))
 460                 return __strncpy_from_user(dst, src, count);
 461         return -EFAULT;
 462 }
 463
 464 /*
 465  * Return the size of a string (including the ending 0)
 466  *
 467  * Return 0 for error
 468  */
 469 #ifndef __powerpc64__
 470 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 471 #else /* __powerpc64__ */
 472 extern int __strnlen_user(const char __user *str, long len);
 473 #endif /* __powerpc64__ */
 474
 475 /*
 476  * Returns the length of the string at str (including the null byte),
 477  * or 0 if we hit a page we can't access,
 478  * or something > len if we didn't find a null byte.
 479  *
 480  * The `top' parameter to __strnlen_user is to make sure that
 481  * we can never overflow from the user area into kernel space.
 482  */
 483 static inline int strnlen_user(const char __user *str, long len)
 484 {
 485 #ifndef __powerpc64__
 486         unsigned long top = current->thread.fs.seg;
 487
 488         if ((unsigned long)str > top)
 489                 return 0;
 490         return __strnlen_user(str, len, top);
 491 #else /* __powerpc64__ */
 492         might_sleep();
 493         if (likely(access_ok(VERIFY_READ, str, 1)))
 494                 return __strnlen_user(str, len);
 495         return 0;
 496 #endif /* __powerpc64__ */
 497 }
 498
 499 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 500
 501 #endif  /* __ASSEMBLY__ */
 502 #endif /* __KERNEL__ */
 503
 504 #endif  /* _ARCH_POWERPC_UACCESS_H */