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 #include <asm/page.h>
  11
  12 #define VERIFY_READ     0
  13 #define VERIFY_WRITE    1
  14
  15 /*
  16  * The fs value determines whether argument validity checking should be
  17  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  18  * get_fs() == KERNEL_DS, checking is bypassed.
  19  *
  20  * For historical reasons, these macros are grossly misnamed.
  21  *
  22  * The fs/ds values are now the highest legal address in the "segment".
  23  * This simplifies the checking in the routines below.
  24  */
  25
  26 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  27
  28 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  29 #ifdef __powerpc64__
  30 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  31 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  32 #else
  33 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  34 #endif
  35
  36 #define get_ds()        (KERNEL_DS)
  37 #define get_fs()        (current->thread.fs)
  38 #define set_fs(val)     (current->thread.fs = (val))
  39
  40 #define segment_eq(a, b)        ((a).seg == (b).seg)
  41
  42 #ifdef __powerpc64__
  43 /*
  44  * This check is sufficient because there is a large enough
  45  * gap between user addresses and the kernel addresses
  46  */
  47 #define __access_ok(addr, size, segment)        \
  48         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  49
  50 #else
  51
  52 #define __access_ok(addr, size, segment)        \
  53         (((addr) <= (segment).seg) &&           \
  54          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  55
  56 #endif
  57
  58 #define access_ok(type, addr, size)             \
  59         (__chk_user_ptr(addr),                  \
  60          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  61
  62 /*
  63  * The exception table consists of pairs of addresses: the first is the
  64  * address of an instruction that is allowed to fault, and the second is
  65  * the address at which the program should continue.  No registers are
  66  * modified, so it is entirely up to the continuation code to figure out
  67  * what to do.
  68  *
  69  * All the routines below use bits of fixup code that are out of line
  70  * with the main instruction path.  This means when everything is well,
  71  * we don't even have to jump over them.  Further, they do not intrude
  72  * on our cache or tlb entries.
  73  */
  74
  75 struct exception_table_entry {
  76         unsigned long insn;
  77         unsigned long fixup;
  78 };
  79
  80 /*
  81  * These are the main single-value transfer routines.  They automatically
  82  * use the right size if we just have the right pointer type.
  83  *
  84  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  85  * and yet we don't want to do any pointers, because that is too much
  86  * of a performance impact. Thus we have a few rather ugly macros here,
  87  * and hide all the ugliness from the user.
  88  *
  89  * The "__xxx" versions of the user access functions are versions that
  90  * do not verify the address space, that must have been done previously
  91  * with a separate "access_ok()" call (this is used when we do multiple
  92  * accesses to the same area of user memory).
  93  *
  94  * As we use the same address space for kernel and user data on the
  95  * PowerPC, we can just do these as direct assignments.  (Of course, the
  96  * exception handling means that it's no longer "just"...)
  97  *
  98  * The "user64" versions of the user access functions are versions that
  99  * allow access of 64-bit data. The "get_user" functions do not
 100  * properly handle 64-bit data because the value gets down cast to a long.
 101  * The "put_user" functions already handle 64-bit data properly but we add
 102  * "user64" versions for completeness
 103  */
 104 #define get_user(x, ptr) \
 105         __get_user_check((x), (ptr), sizeof(*(ptr)))
 106 #define put_user(x, ptr) \
 107         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 108
 109 #define __get_user(x, ptr) \
 110         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 111 #define __put_user(x, ptr) \
 112         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 113
 114 #ifndef __powerpc64__
 115 #define __get_user64(x, ptr) \
 116         __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
 117 #define __put_user64(x, ptr) __put_user(x, ptr)
 118 #endif
 119
 120 #define __get_user_inatomic(x, ptr) \
 121         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 122 #define __put_user_inatomic(x, ptr) \
 123         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 124
 125 #define __get_user_unaligned __get_user
 126 #define __put_user_unaligned __put_user
 127
 128 extern long __put_user_bad(void);
 129
 130 /*
 131  * We don't tell gcc that we are accessing memory, but this is OK
 132  * because we do not write to any memory gcc knows about, so there
 133  * are no aliasing issues.
 134  */
 135 #define __put_user_asm(x, addr, err, op)                        \
 136         __asm__ __volatile__(                                   \
 137                 "1:     " op " %1,0(%2) # put_user\n"           \
 138                 "2:\n"                                          \
 139                 ".section .fixup,\"ax\"\n"                      \
 140                 "3:     li %0,%3\n"                             \
 141                 "       b 2b\n"                                 \
 142                 ".previous\n"                                   \
 143                 ".section __ex_table,\"a\"\n"                   \
 144                 "       .balign %5\n"                           \
 145                         PPC_LONG "1b,3b\n"                      \
 146                 ".previous"                                     \
 147                 : "=r" (err)                                    \
 148                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err),\
 149                   "i"(sizeof(unsigned long)))
 150
 151 #ifdef __powerpc64__
 152 #define __put_user_asm2(x, ptr, retval)                         \
 153           __put_user_asm(x, ptr, retval, "std")
 154 #else /* __powerpc64__ */
 155 #define __put_user_asm2(x, addr, err)                           \
 156         __asm__ __volatile__(                                   \
 157                 "1:     stw %1,0(%2)\n"                         \
 158                 "2:     stw %1+1,4(%2)\n"                       \
 159                 "3:\n"                                          \
 160                 ".section .fixup,\"ax\"\n"                      \
 161                 "4:     li %0,%3\n"                             \
 162                 "       b 3b\n"                                 \
 163                 ".previous\n"                                   \
 164                 ".section __ex_table,\"a\"\n"                   \
 165                 "       .balign %5\n"                           \
 166                         PPC_LONG "1b,4b\n"                      \
 167                         PPC_LONG "2b,4b\n"                      \
 168                 ".previous"                                     \
 169                 : "=r" (err)                                    \
 170                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err),\
 171                   "i"(sizeof(unsigned long)))
 172 #endif /* __powerpc64__ */
 173
 174 #define __put_user_size(x, ptr, size, retval)                   \
 175 do {                                                            \
 176         retval = 0;                                             \
 177         switch (size) {                                         \
 178           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 179           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 180           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 181           case 8: __put_user_asm2(x, ptr, retval); break;       \
 182           default: __put_user_bad();                            \
 183         }                                                       \
 184 } while (0)
 185
 186 #define __put_user_nocheck(x, ptr, size)                        \
 187 ({                                                              \
 188         long __pu_err;                                          \
 189         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 190         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 191                 might_sleep();                                  \
 192         __chk_user_ptr(ptr);                                    \
 193         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 194         __pu_err;                                               \
 195 })
 196
 197 #define __put_user_check(x, ptr, size)                                  \
 198 ({                                                                      \
 199         long __pu_err = -EFAULT;                                        \
 200         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 201         might_sleep();                                                  \
 202         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 203                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 204         __pu_err;                                                       \
 205 })
 206
 207 #define __put_user_nosleep(x, ptr, size)                        \
 208 ({                                                              \
 209         long __pu_err;                                          \
 210         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 211         __chk_user_ptr(ptr);                                    \
 212         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 213         __pu_err;                                               \
 214 })
 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                 "       .balign %5\n"                   \
 230                         PPC_LONG "1b,3b\n"              \
 231                 ".previous"                             \
 232                 : "=r" (err), "=r" (x)                  \
 233                 : "b" (addr), "i" (-EFAULT), "0" (err), \
 234                   "i"(sizeof(unsigned long)))
 235
 236 #ifdef __powerpc64__
 237 #define __get_user_asm2(x, addr, err)                   \
 238         __get_user_asm(x, addr, err, "ld")
 239 #else /* __powerpc64__ */
 240 #define __get_user_asm2(x, addr, err)                   \
 241         __asm__ __volatile__(                           \
 242                 "1:     lwz %1,0(%2)\n"                 \
 243                 "2:     lwz %1+1,4(%2)\n"               \
 244                 "3:\n"                                  \
 245                 ".section .fixup,\"ax\"\n"              \
 246                 "4:     li %0,%3\n"                     \
 247                 "       li %1,0\n"                      \
 248                 "       li %1+1,0\n"                    \
 249                 "       b 3b\n"                         \
 250                 ".previous\n"                           \
 251                 ".section __ex_table,\"a\"\n"           \
 252                 "       .balign %5\n"                   \
 253                         PPC_LONG "1b,4b\n"              \
 254                         PPC_LONG "2b,4b\n"              \
 255                 ".previous"                             \
 256                 : "=r" (err), "=&r" (x)                 \
 257                 : "b" (addr), "i" (-EFAULT), "0" (err), \
 258                   "i"(sizeof(unsigned long)))
 259 #endif /* __powerpc64__ */
 260
 261 #define __get_user_size(x, ptr, size, retval)                   \
 262 do {                                                            \
 263         retval = 0;                                             \
 264         __chk_user_ptr(ptr);                                    \
 265         if (size > sizeof(x))                                   \
 266                 (x) = __get_user_bad();                         \
 267         switch (size) {                                         \
 268         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 269         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 270         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 271         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 272         default: (x) = __get_user_bad();                        \
 273         }                                                       \
 274 } while (0)
 275
 276 #define __get_user_nocheck(x, ptr, size)                        \
 277 ({                                                              \
 278         long __gu_err;                                          \
 279         unsigned long __gu_val;                                 \
 280         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 281         __chk_user_ptr(ptr);                                    \
 282         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 283                 might_sleep();                                  \
 284         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 285         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 286         __gu_err;                                               \
 287 })
 288
 289 #ifndef __powerpc64__
 290 #define __get_user64_nocheck(x, ptr, size)                      \
 291 ({                                                              \
 292         long __gu_err;                                          \
 293         long long __gu_val;                                     \
 294         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 295         __chk_user_ptr(ptr);                                    \
 296         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 297                 might_sleep();                                  \
 298         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 299         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 300         __gu_err;                                               \
 301 })
 302 #endif /* __powerpc64__ */
 303
 304 #define __get_user_check(x, ptr, size)                                  \
 305 ({                                                                      \
 306         long __gu_err = -EFAULT;                                        \
 307         unsigned long  __gu_val = 0;                                    \
 308         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 309         might_sleep();                                                  \
 310         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 311                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 312         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 313         __gu_err;                                                       \
 314 })
 315
 316 #define __get_user_nosleep(x, ptr, size)                        \
 317 ({                                                              \
 318         long __gu_err;                                          \
 319         unsigned long __gu_val;                                 \
 320         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 321         __chk_user_ptr(ptr);                                    \
 322         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 323         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 324         __gu_err;                                               \
 325 })
 326
 327
 328 /* more complex routines */
 329
 330 extern unsigned long __copy_tofrom_user(void __user *to,
 331                 const void __user *from, unsigned long size);
 332
 333 #ifndef __powerpc64__
 334
 335 static inline unsigned long copy_from_user(void *to,
 336                 const void __user *from, unsigned long n)
 337 {
 338         unsigned long over;
 339
 340         if (access_ok(VERIFY_READ, from, n))
 341                 return __copy_tofrom_user((__force void __user *)to, from, n);
 342         if ((unsigned long)from < TASK_SIZE) {
 343                 over = (unsigned long)from + n - TASK_SIZE;
 344                 return __copy_tofrom_user((__force void __user *)to, from,
 345                                 n - over) + over;
 346         }
 347         return n;
 348 }
 349
 350 static inline unsigned long copy_to_user(void __user *to,
 351                 const void *from, unsigned long n)
 352 {
 353         unsigned long over;
 354
 355         if (access_ok(VERIFY_WRITE, to, n))
 356                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 357         if ((unsigned long)to < TASK_SIZE) {
 358                 over = (unsigned long)to + n - TASK_SIZE;
 359                 return __copy_tofrom_user(to, (__force void __user *)from,
 360                                 n - over) + over;
 361         }
 362         return n;
 363 }
 364
 365 #else /* __powerpc64__ */
 366
 367 #define __copy_in_user(to, from, size) \
 368         __copy_tofrom_user((to), (from), (size))
 369
 370 extern unsigned long copy_from_user(void *to, const void __user *from,
 371                                     unsigned long n);
 372 extern unsigned long copy_to_user(void __user *to, const void *from,
 373                                   unsigned long n);
 374 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 375                                   unsigned long n);
 376
 377 #endif /* __powerpc64__ */
 378
 379 static inline unsigned long __copy_from_user_inatomic(void *to,
 380                 const void __user *from, unsigned long n)
 381 {
 382         if (__builtin_constant_p(n) && (n <= 8)) {
 383                 unsigned long ret = 1;
 384
 385                 switch (n) {
 386                 case 1:
 387                         __get_user_size(*(u8 *)to, from, 1, ret);
 388                         break;
 389                 case 2:
 390                         __get_user_size(*(u16 *)to, from, 2, ret);
 391                         break;
 392                 case 4:
 393                         __get_user_size(*(u32 *)to, from, 4, ret);
 394                         break;
 395                 case 8:
 396                         __get_user_size(*(u64 *)to, from, 8, ret);
 397                         break;
 398                 }
 399                 if (ret == 0)
 400                         return 0;
 401         }
 402         return __copy_tofrom_user((__force void __user *)to, from, n);
 403 }
 404
 405 static inline unsigned long __copy_to_user_inatomic(void __user *to,
 406                 const void *from, unsigned long n)
 407 {
 408         if (__builtin_constant_p(n) && (n <= 8)) {
 409                 unsigned long ret = 1;
 410
 411                 switch (n) {
 412                 case 1:
 413                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 414                         break;
 415                 case 2:
 416                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 417                         break;
 418                 case 4:
 419                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 420                         break;
 421                 case 8:
 422                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 423                         break;
 424                 }
 425                 if (ret == 0)
 426                         return 0;
 427         }
 428         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 429 }
 430
 431 static inline unsigned long __copy_from_user(void *to,
 432                 const void __user *from, unsigned long size)
 433 {
 434         might_sleep();
 435         return __copy_from_user_inatomic(to, from, size);
 436 }
 437
 438 static inline unsigned long __copy_to_user(void __user *to,
 439                 const void *from, unsigned long size)
 440 {
 441         might_sleep();
 442         return __copy_to_user_inatomic(to, from, size);
 443 }
 444
 445 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 446
 447 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 448 {
 449         might_sleep();
 450         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 451                 return __clear_user(addr, size);
 452         if ((unsigned long)addr < TASK_SIZE) {
 453                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 454                 return __clear_user(addr, size - over) + over;
 455         }
 456         return size;
 457 }
 458
 459 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 460
 461 static inline long strncpy_from_user(char *dst, const char __user *src,
 462                 long count)
 463 {
 464         might_sleep();
 465         if (likely(access_ok(VERIFY_READ, src, 1)))
 466                 return __strncpy_from_user(dst, src, count);
 467         return -EFAULT;
 468 }
 469
 470 /*
 471  * Return the size of a string (including the ending 0)
 472  *
 473  * Return 0 for error
 474  */
 475 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 476
 477 /*
 478  * Returns the length of the string at str (including the null byte),
 479  * or 0 if we hit a page we can't access,
 480  * or something > len if we didn't find a null byte.
 481  *
 482  * The `top' parameter to __strnlen_user is to make sure that
 483  * we can never overflow from the user area into kernel space.
 484  */
 485 static inline int strnlen_user(const char __user *str, long len)
 486 {
 487         unsigned long top = current->thread.fs.seg;
 488
 489         if ((unsigned long)str > top)
 490                 return 0;
 491         return __strnlen_user(str, len, top);
 492 }
 493
 494 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 495
 496 #endif  /* __ASSEMBLY__ */
 497 #endif /* __KERNEL__ */
 498
 499 #endif  /* _ARCH_POWERPC_UACCESS_H */