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/asm-compat.h>
  10 #include <asm/processor.h>
  11 #include <asm/page.h>
  12
  13 #define VERIFY_READ     0
  14 #define VERIFY_WRITE    1
  15
  16 /*
  17  * The fs value determines whether argument validity checking should be
  18  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  19  * get_fs() == KERNEL_DS, checking is bypassed.
  20  *
  21  * For historical reasons, these macros are grossly misnamed.
  22  *
  23  * The fs/ds values are now the highest legal address in the "segment".
  24  * This simplifies the checking in the routines below.
  25  */
  26
  27 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  28
  29 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  30 #ifdef __powerpc64__
  31 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  32 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  33 #else
  34 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  35 #endif
  36
  37 #define get_ds()        (KERNEL_DS)
  38 #define get_fs()        (current->thread.fs)
  39 #define set_fs(val)     (current->thread.fs = (val))
  40
  41 #define segment_eq(a, b)        ((a).seg == (b).seg)
  42
  43 #ifdef __powerpc64__
  44 /*
  45  * This check is sufficient because there is a large enough
  46  * gap between user addresses and the kernel addresses
  47  */
  48 #define __access_ok(addr, size, segment)        \
  49         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  50
  51 #else
  52
  53 #define __access_ok(addr, size, segment)        \
  54         (((addr) <= (segment).seg) &&           \
  55          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  56
  57 #endif
  58
  59 #define access_ok(type, addr, size)             \
  60         (__chk_user_ptr(addr),                  \
  61          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  62
  63 /*
  64  * The exception table consists of pairs of addresses: the first is the
  65  * address of an instruction that is allowed to fault, and the second is
  66  * the address at which the program should continue.  No registers are
  67  * modified, so it is entirely up to the continuation code to figure out
  68  * what to do.
  69  *
  70  * All the routines below use bits of fixup code that are out of line
  71  * with the main instruction path.  This means when everything is well,
  72  * we don't even have to jump over them.  Further, they do not intrude
  73  * on our cache or tlb entries.
  74  */
  75
  76 struct exception_table_entry {
  77         unsigned long insn;
  78         unsigned long fixup;
  79 };
  80
  81 /*
  82  * These are the main single-value transfer routines.  They automatically
  83  * use the right size if we just have the right pointer type.
  84  *
  85  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  86  * and yet we don't want to do any pointers, because that is too much
  87  * of a performance impact. Thus we have a few rather ugly macros here,
  88  * and hide all the ugliness from the user.
  89  *
  90  * The "__xxx" versions of the user access functions are versions that
  91  * do not verify the address space, that must have been done previously
  92  * with a separate "access_ok()" call (this is used when we do multiple
  93  * accesses to the same area of user memory).
  94  *
  95  * As we use the same address space for kernel and user data on the
  96  * PowerPC, we can just do these as direct assignments.  (Of course, the
  97  * exception handling means that it's no longer "just"...)
  98  *
  99  * The "user64" versions of the user access functions are versions that
 100  * allow access of 64-bit data. The "get_user" functions do not
 101  * properly handle 64-bit data because the value gets down cast to a long.
 102  * The "put_user" functions already handle 64-bit data properly but we add
 103  * "user64" versions for completeness
 104  */
 105 #define get_user(x, ptr) \
 106         __get_user_check((x), (ptr), sizeof(*(ptr)))
 107 #define put_user(x, ptr) \
 108         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 109
 110 #define __get_user(x, ptr) \
 111         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 112 #define __put_user(x, ptr) \
 113         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 114
 115 #ifndef __powerpc64__
 116 #define __get_user64(x, ptr) \
 117         __get_user64_nocheck((x), (ptr), sizeof(*(ptr)))
 118 #define __put_user64(x, ptr) __put_user(x, ptr)
 119 #endif
 120
 121 #define __get_user_inatomic(x, ptr) \
 122         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 123 #define __put_user_inatomic(x, ptr) \
 124         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 125
 126 #define __get_user_unaligned __get_user
 127 #define __put_user_unaligned __put_user
 128
 129 extern long __put_user_bad(void);
 130
 131 /*
 132  * We don't tell gcc that we are accessing memory, but this is OK
 133  * because we do not write to any memory gcc knows about, so there
 134  * are no aliasing issues.
 135  */
 136 #define __put_user_asm(x, addr, err, op)                        \
 137         __asm__ __volatile__(                                   \
 138                 "1:     " op " %1,0(%2) # put_user\n"           \
 139                 "2:\n"                                          \
 140                 ".section .fixup,\"ax\"\n"                      \
 141                 "3:     li %0,%3\n"                             \
 142                 "       b 2b\n"                                 \
 143                 ".previous\n"                                   \
 144                 ".section __ex_table,\"a\"\n"                   \
 145                         PPC_LONG_ALIGN "\n"                     \
 146                         PPC_LONG "1b,3b\n"                      \
 147                 ".previous"                                     \
 148                 : "=r" (err)                                    \
 149                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 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                         PPC_LONG_ALIGN "\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 #endif /* __powerpc64__ */
 172
 173 #define __put_user_size(x, ptr, size, retval)                   \
 174 do {                                                            \
 175         retval = 0;                                             \
 176         switch (size) {                                         \
 177           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 178           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 179           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 180           case 8: __put_user_asm2(x, ptr, retval); break;       \
 181           default: __put_user_bad();                            \
 182         }                                                       \
 183 } while (0)
 184
 185 #define __put_user_nocheck(x, ptr, size)                        \
 186 ({                                                              \
 187         long __pu_err;                                          \
 188         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 189         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 190                 might_sleep();                                  \
 191         __chk_user_ptr(ptr);                                    \
 192         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 193         __pu_err;                                               \
 194 })
 195
 196 #define __put_user_check(x, ptr, size)                                  \
 197 ({                                                                      \
 198         long __pu_err = -EFAULT;                                        \
 199         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 200         might_sleep();                                                  \
 201         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 202                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 203         __pu_err;                                                       \
 204 })
 205
 206 #define __put_user_nosleep(x, ptr, size)                        \
 207 ({                                                              \
 208         long __pu_err;                                          \
 209         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 210         __chk_user_ptr(ptr);                                    \
 211         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 212         __pu_err;                                               \
 213 })
 214
 215
 216 extern long __get_user_bad(void);
 217
 218 #define __get_user_asm(x, addr, err, op)                \
 219         __asm__ __volatile__(                           \
 220                 "1:     "op" %1,0(%2)   # get_user\n"   \
 221                 "2:\n"                                  \
 222                 ".section .fixup,\"ax\"\n"              \
 223                 "3:     li %0,%3\n"                     \
 224                 "       li %1,0\n"                      \
 225                 "       b 2b\n"                         \
 226                 ".previous\n"                           \
 227                 ".section __ex_table,\"a\"\n"           \
 228                         PPC_LONG_ALIGN "\n"             \
 229                         PPC_LONG "1b,3b\n"              \
 230                 ".previous"                             \
 231                 : "=r" (err), "=r" (x)                  \
 232                 : "b" (addr), "i" (-EFAULT), "0" (err))
 233
 234 #ifdef __powerpc64__
 235 #define __get_user_asm2(x, addr, err)                   \
 236         __get_user_asm(x, addr, err, "ld")
 237 #else /* __powerpc64__ */
 238 #define __get_user_asm2(x, addr, err)                   \
 239         __asm__ __volatile__(                           \
 240                 "1:     lwz %1,0(%2)\n"                 \
 241                 "2:     lwz %1+1,4(%2)\n"               \
 242                 "3:\n"                                  \
 243                 ".section .fixup,\"ax\"\n"              \
 244                 "4:     li %0,%3\n"                     \
 245                 "       li %1,0\n"                      \
 246                 "       li %1+1,0\n"                    \
 247                 "       b 3b\n"                         \
 248                 ".previous\n"                           \
 249                 ".section __ex_table,\"a\"\n"           \
 250                         PPC_LONG_ALIGN "\n"             \
 251                         PPC_LONG "1b,4b\n"              \
 252                         PPC_LONG "2b,4b\n"              \
 253                 ".previous"                             \
 254                 : "=r" (err), "=&r" (x)                 \
 255                 : "b" (addr), "i" (-EFAULT), "0" (err))
 256 #endif /* __powerpc64__ */
 257
 258 #define __get_user_size(x, ptr, size, retval)                   \
 259 do {                                                            \
 260         retval = 0;                                             \
 261         __chk_user_ptr(ptr);                                    \
 262         if (size > sizeof(x))                                   \
 263                 (x) = __get_user_bad();                         \
 264         switch (size) {                                         \
 265         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 266         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 267         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 268         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 269         default: (x) = __get_user_bad();                        \
 270         }                                                       \
 271 } while (0)
 272
 273 #define __get_user_nocheck(x, ptr, size)                        \
 274 ({                                                              \
 275         long __gu_err;                                          \
 276         unsigned long __gu_val;                                 \
 277         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 278         __chk_user_ptr(ptr);                                    \
 279         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 280                 might_sleep();                                  \
 281         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 282         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 283         __gu_err;                                               \
 284 })
 285
 286 #ifndef __powerpc64__
 287 #define __get_user64_nocheck(x, ptr, size)                      \
 288 ({                                                              \
 289         long __gu_err;                                          \
 290         long long __gu_val;                                     \
 291         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 292         __chk_user_ptr(ptr);                                    \
 293         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 294                 might_sleep();                                  \
 295         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 296         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 297         __gu_err;                                               \
 298 })
 299 #endif /* __powerpc64__ */
 300
 301 #define __get_user_check(x, ptr, size)                                  \
 302 ({                                                                      \
 303         long __gu_err = -EFAULT;                                        \
 304         unsigned long  __gu_val = 0;                                    \
 305         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 306         might_sleep();                                                  \
 307         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 308                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 309         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 310         __gu_err;                                                       \
 311 })
 312
 313 #define __get_user_nosleep(x, ptr, size)                        \
 314 ({                                                              \
 315         long __gu_err;                                          \
 316         unsigned long __gu_val;                                 \
 317         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 318         __chk_user_ptr(ptr);                                    \
 319         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 320         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 321         __gu_err;                                               \
 322 })
 323
 324
 325 /* more complex routines */
 326
 327 extern unsigned long __copy_tofrom_user(void __user *to,
 328                 const void __user *from, unsigned long size);
 329
 330 #ifndef __powerpc64__
 331
 332 static inline unsigned long copy_from_user(void *to,
 333                 const void __user *from, unsigned long n)
 334 {
 335         unsigned long over;
 336
 337         if (access_ok(VERIFY_READ, from, n))
 338                 return __copy_tofrom_user((__force void __user *)to, from, n);
 339         if ((unsigned long)from < TASK_SIZE) {
 340                 over = (unsigned long)from + n - TASK_SIZE;
 341                 return __copy_tofrom_user((__force void __user *)to, from,
 342                                 n - over) + over;
 343         }
 344         return n;
 345 }
 346
 347 static inline unsigned long copy_to_user(void __user *to,
 348                 const void *from, unsigned long n)
 349 {
 350         unsigned long over;
 351
 352         if (access_ok(VERIFY_WRITE, to, n))
 353                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 354         if ((unsigned long)to < TASK_SIZE) {
 355                 over = (unsigned long)to + n - TASK_SIZE;
 356                 return __copy_tofrom_user(to, (__force void __user *)from,
 357                                 n - over) + over;
 358         }
 359         return n;
 360 }
 361
 362 #else /* __powerpc64__ */
 363
 364 #define __copy_in_user(to, from, size) \
 365         __copy_tofrom_user((to), (from), (size))
 366
 367 extern unsigned long copy_from_user(void *to, const void __user *from,
 368                                     unsigned long n);
 369 extern unsigned long copy_to_user(void __user *to, const void *from,
 370                                   unsigned long n);
 371 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 372                                   unsigned long n);
 373
 374 #endif /* __powerpc64__ */
 375
 376 static inline unsigned long __copy_from_user_inatomic(void *to,
 377                 const void __user *from, unsigned long n)
 378 {
 379         if (__builtin_constant_p(n) && (n <= 8)) {
 380                 unsigned long ret = 1;
 381
 382                 switch (n) {
 383                 case 1:
 384                         __get_user_size(*(u8 *)to, from, 1, ret);
 385                         break;
 386                 case 2:
 387                         __get_user_size(*(u16 *)to, from, 2, ret);
 388                         break;
 389                 case 4:
 390                         __get_user_size(*(u32 *)to, from, 4, ret);
 391                         break;
 392                 case 8:
 393                         __get_user_size(*(u64 *)to, from, 8, ret);
 394                         break;
 395                 }
 396                 if (ret == 0)
 397                         return 0;
 398         }
 399         return __copy_tofrom_user((__force void __user *)to, from, n);
 400 }
 401
 402 static inline unsigned long __copy_to_user_inatomic(void __user *to,
 403                 const void *from, unsigned long n)
 404 {
 405         if (__builtin_constant_p(n) && (n <= 8)) {
 406                 unsigned long ret = 1;
 407
 408                 switch (n) {
 409                 case 1:
 410                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 411                         break;
 412                 case 2:
 413                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 414                         break;
 415                 case 4:
 416                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 417                         break;
 418                 case 8:
 419                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 420                         break;
 421                 }
 422                 if (ret == 0)
 423                         return 0;
 424         }
 425         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 426 }
 427
 428 static inline unsigned long __copy_from_user(void *to,
 429                 const void __user *from, unsigned long size)
 430 {
 431         might_sleep();
 432         return __copy_from_user_inatomic(to, from, size);
 433 }
 434
 435 static inline unsigned long __copy_to_user(void __user *to,
 436                 const void *from, unsigned long size)
 437 {
 438         might_sleep();
 439         return __copy_to_user_inatomic(to, from, size);
 440 }
 441
 442 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 443
 444 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 445 {
 446         might_sleep();
 447         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 448                 return __clear_user(addr, size);
 449         if ((unsigned long)addr < TASK_SIZE) {
 450                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 451                 return __clear_user(addr, size - over) + over;
 452         }
 453         return size;
 454 }
 455
 456 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 457
 458 static inline long strncpy_from_user(char *dst, const char __user *src,
 459                 long count)
 460 {
 461         might_sleep();
 462         if (likely(access_ok(VERIFY_READ, src, 1)))
 463                 return __strncpy_from_user(dst, src, count);
 464         return -EFAULT;
 465 }
 466
 467 /*
 468  * Return the size of a string (including the ending 0)
 469  *
 470  * Return 0 for error
 471  */
 472 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 473
 474 /*
 475  * Returns the length of the string at str (including the null byte),
 476  * or 0 if we hit a page we can't access,
 477  * or something > len if we didn't find a null byte.
 478  *
 479  * The `top' parameter to __strnlen_user is to make sure that
 480  * we can never overflow from the user area into kernel space.
 481  */
 482 static inline int strnlen_user(const char __user *str, long len)
 483 {
 484         unsigned long top = current->thread.fs.seg;
 485
 486         if ((unsigned long)str > top)
 487                 return 0;
 488         return __strnlen_user(str, len, top);
 489 }
 490
 491 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 492
 493 #endif  /* __ASSEMBLY__ */
 494 #endif /* __KERNEL__ */
 495
 496 #endif  /* _ARCH_POWERPC_UACCESS_H */