arch/powerpc/include/asm/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 #define user_addr_max() (get_fs().seg)
  44
  45 #ifdef __powerpc64__
  46 /*
  47  * This check is sufficient because there is a large enough
  48  * gap between user addresses and the kernel addresses
  49  */
  50 #define __access_ok(addr, size, segment)        \
  51         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  52
  53 #else
  54
  55 #define __access_ok(addr, size, segment)        \
  56         (((addr) <= (segment).seg) &&           \
  57          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  58
  59 #endif
  60
  61 #define access_ok(type, addr, size)             \
  62         (__chk_user_ptr(addr),                  \
  63          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  64
  65 /*
  66  * The exception table consists of pairs of addresses: the first is the
  67  * address of an instruction that is allowed to fault, and the second is
  68  * the address at which the program should continue.  No registers are
  69  * modified, so it is entirely up to the continuation code to figure out
  70  * what to do.
  71  *
  72  * All the routines below use bits of fixup code that are out of line
  73  * with the main instruction path.  This means when everything is well,
  74  * we don't even have to jump over them.  Further, they do not intrude
  75  * on our cache or tlb entries.
  76  */
  77
  78 struct exception_table_entry {
  79         unsigned long insn;
  80         unsigned long fixup;
  81 };
  82
  83 /*
  84  * These are the main single-value transfer routines.  They automatically
  85  * use the right size if we just have the right pointer type.
  86  *
  87  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  88  * and yet we don't want to do any pointers, because that is too much
  89  * of a performance impact. Thus we have a few rather ugly macros here,
  90  * and hide all the ugliness from the user.
  91  *
  92  * The "__xxx" versions of the user access functions are versions that
  93  * do not verify the address space, that must have been done previously
  94  * with a separate "access_ok()" call (this is used when we do multiple
  95  * accesses to the same area of user memory).
  96  *
  97  * As we use the same address space for kernel and user data on the
  98  * PowerPC, we can just do these as direct assignments.  (Of course, the
  99  * exception handling means that it's no longer "just"...)
 100  *
 101  */
 102 #define get_user(x, ptr) \
 103         __get_user_check((x), (ptr), sizeof(*(ptr)))
 104 #define put_user(x, ptr) \
 105         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 106
 107 #define __get_user(x, ptr) \
 108         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 109 #define __put_user(x, ptr) \
 110         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 111
 112 #define __get_user_inatomic(x, ptr) \
 113         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 114 #define __put_user_inatomic(x, ptr) \
 115         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 116
 117 #define __get_user_unaligned __get_user
 118 #define __put_user_unaligned __put_user
 119
 120 extern long __put_user_bad(void);
 121
 122 /*
 123  * We don't tell gcc that we are accessing memory, but this is OK
 124  * because we do not write to any memory gcc knows about, so there
 125  * are no aliasing issues.
 126  */
 127 #define __put_user_asm(x, addr, err, op)                        \
 128         __asm__ __volatile__(                                   \
 129                 "1:     " op " %1,0(%2) # put_user\n"           \
 130                 "2:\n"                                          \
 131                 ".section .fixup,\"ax\"\n"                      \
 132                 "3:     li %0,%3\n"                             \
 133                 "       b 2b\n"                                 \
 134                 ".previous\n"                                   \
 135                 ".section __ex_table,\"a\"\n"                   \
 136                         PPC_LONG_ALIGN "\n"                     \
 137                         PPC_LONG "1b,3b\n"                      \
 138                 ".previous"                                     \
 139                 : "=r" (err)                                    \
 140                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 141
 142 #ifdef __powerpc64__
 143 #define __put_user_asm2(x, ptr, retval)                         \
 144           __put_user_asm(x, ptr, retval, "std")
 145 #else /* __powerpc64__ */
 146 #define __put_user_asm2(x, addr, err)                           \
 147         __asm__ __volatile__(                                   \
 148                 "1:     stw %1,0(%2)\n"                         \
 149                 "2:     stw %1+1,4(%2)\n"                       \
 150                 "3:\n"                                          \
 151                 ".section .fixup,\"ax\"\n"                      \
 152                 "4:     li %0,%3\n"                             \
 153                 "       b 3b\n"                                 \
 154                 ".previous\n"                                   \
 155                 ".section __ex_table,\"a\"\n"                   \
 156                         PPC_LONG_ALIGN "\n"                     \
 157                         PPC_LONG "1b,4b\n"                      \
 158                         PPC_LONG "2b,4b\n"                      \
 159                 ".previous"                                     \
 160                 : "=r" (err)                                    \
 161                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 162 #endif /* __powerpc64__ */
 163
 164 #define __put_user_size(x, ptr, size, retval)                   \
 165 do {                                                            \
 166         retval = 0;                                             \
 167         switch (size) {                                         \
 168           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 169           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 170           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 171           case 8: __put_user_asm2(x, ptr, retval); break;       \
 172           default: __put_user_bad();                            \
 173         }                                                       \
 174 } while (0)
 175
 176 #define __put_user_nocheck(x, ptr, size)                        \
 177 ({                                                              \
 178         long __pu_err;                                          \
 179         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 180         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 181                 might_fault();                                  \
 182         __chk_user_ptr(ptr);                                    \
 183         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 184         __pu_err;                                               \
 185 })
 186
 187 #define __put_user_check(x, ptr, size)                                  \
 188 ({                                                                      \
 189         long __pu_err = -EFAULT;                                        \
 190         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 191         might_fault();                                                  \
 192         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 193                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 194         __pu_err;                                                       \
 195 })
 196
 197 #define __put_user_nosleep(x, ptr, size)                        \
 198 ({                                                              \
 199         long __pu_err;                                          \
 200         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 201         __chk_user_ptr(ptr);                                    \
 202         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 203         __pu_err;                                               \
 204 })
 205
 206
 207 extern long __get_user_bad(void);
 208
 209 #define __get_user_asm(x, addr, err, op)                \
 210         __asm__ __volatile__(                           \
 211                 "1:     "op" %1,0(%2)   # get_user\n"   \
 212                 "2:\n"                                  \
 213                 ".section .fixup,\"ax\"\n"              \
 214                 "3:     li %0,%3\n"                     \
 215                 "       li %1,0\n"                      \
 216                 "       b 2b\n"                         \
 217                 ".previous\n"                           \
 218                 ".section __ex_table,\"a\"\n"           \
 219                         PPC_LONG_ALIGN "\n"             \
 220                         PPC_LONG "1b,3b\n"              \
 221                 ".previous"                             \
 222                 : "=r" (err), "=r" (x)                  \
 223                 : "b" (addr), "i" (-EFAULT), "0" (err))
 224
 225 #ifdef __powerpc64__
 226 #define __get_user_asm2(x, addr, err)                   \
 227         __get_user_asm(x, addr, err, "ld")
 228 #else /* __powerpc64__ */
 229 #define __get_user_asm2(x, addr, err)                   \
 230         __asm__ __volatile__(                           \
 231                 "1:     lwz %1,0(%2)\n"                 \
 232                 "2:     lwz %1+1,4(%2)\n"               \
 233                 "3:\n"                                  \
 234                 ".section .fixup,\"ax\"\n"              \
 235                 "4:     li %0,%3\n"                     \
 236                 "       li %1,0\n"                      \
 237                 "       li %1+1,0\n"                    \
 238                 "       b 3b\n"                         \
 239                 ".previous\n"                           \
 240                 ".section __ex_table,\"a\"\n"           \
 241                         PPC_LONG_ALIGN "\n"             \
 242                         PPC_LONG "1b,4b\n"              \
 243                         PPC_LONG "2b,4b\n"              \
 244                 ".previous"                             \
 245                 : "=r" (err), "=&r" (x)                 \
 246                 : "b" (addr), "i" (-EFAULT), "0" (err))
 247 #endif /* __powerpc64__ */
 248
 249 #define __get_user_size(x, ptr, size, retval)                   \
 250 do {                                                            \
 251         retval = 0;                                             \
 252         __chk_user_ptr(ptr);                                    \
 253         if (size > sizeof(x))                                   \
 254                 (x) = __get_user_bad();                         \
 255         switch (size) {                                         \
 256         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 257         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 258         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 259         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 260         default: (x) = __get_user_bad();                        \
 261         }                                                       \
 262 } while (0)
 263
 264 #define __get_user_nocheck(x, ptr, size)                        \
 265 ({                                                              \
 266         long __gu_err;                                          \
 267         unsigned long __gu_val;                                 \
 268         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 269         __chk_user_ptr(ptr);                                    \
 270         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 271                 might_fault();                                  \
 272         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 273         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 274         __gu_err;                                               \
 275 })
 276
 277 #define __get_user_check(x, ptr, size)                                  \
 278 ({                                                                      \
 279         long __gu_err = -EFAULT;                                        \
 280         unsigned long  __gu_val = 0;                                    \
 281         __typeof__(*(ptr)) __user *__gu_addr = (ptr);           \
 282         might_fault();                                                  \
 283         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 284                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 285         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 286         __gu_err;                                                       \
 287 })
 288
 289 #define __get_user_nosleep(x, ptr, size)                        \
 290 ({                                                              \
 291         long __gu_err;                                          \
 292         unsigned long __gu_val;                                 \
 293         __typeof__(*(ptr)) __user *__gu_addr = (ptr);   \
 294         __chk_user_ptr(ptr);                                    \
 295         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 296         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 297         __gu_err;                                               \
 298 })
 299
 300
 301 /* more complex routines */
 302
 303 extern unsigned long __copy_tofrom_user(void __user *to,
 304                 const void __user *from, unsigned long size);
 305
 306 #ifndef __powerpc64__
 307
 308 static inline unsigned long copy_from_user(void *to,
 309                 const void __user *from, unsigned long n)
 310 {
 311         unsigned long over;
 312
 313         if (access_ok(VERIFY_READ, from, n)) {
 314                 if (!__builtin_constant_p(n))
 315                         check_object_size(to, n, false);
 316                 return __copy_tofrom_user((__force void __user *)to, from, n);
 317         }
 318         if ((unsigned long)from < TASK_SIZE) {
 319                 over = (unsigned long)from + n - TASK_SIZE;
 320                 if (!__builtin_constant_p(n - over))
 321                         check_object_size(to, n - over, false);
 322                 return __copy_tofrom_user((__force void __user *)to, from,
 323                                 n - over) + over;
 324         }
 325         return n;
 326 }
 327
 328 static inline unsigned long copy_to_user(void __user *to,
 329                 const void *from, unsigned long n)
 330 {
 331         unsigned long over;
 332
 333         if (access_ok(VERIFY_WRITE, to, n)) {
 334                 if (!__builtin_constant_p(n))
 335                         check_object_size(from, n, true);
 336                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 337         }
 338         if ((unsigned long)to < TASK_SIZE) {
 339                 over = (unsigned long)to + n - TASK_SIZE;
 340                 if (!__builtin_constant_p(n))
 341                         check_object_size(from, n - over, true);
 342                 return __copy_tofrom_user(to, (__force void __user *)from,
 343                                 n - over) + over;
 344         }
 345         return n;
 346 }
 347
 348 #else /* __powerpc64__ */
 349
 350 #define __copy_in_user(to, from, size) \
 351         __copy_tofrom_user((to), (from), (size))
 352
 353 extern unsigned long copy_from_user(void *to, const void __user *from,
 354                                     unsigned long n);
 355 extern unsigned long copy_to_user(void __user *to, const void *from,
 356                                   unsigned long n);
 357 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 358                                   unsigned long n);
 359
 360 #endif /* __powerpc64__ */
 361
 362 static inline unsigned long __copy_from_user_inatomic(void *to,
 363                 const void __user *from, unsigned long n)
 364 {
 365         if (__builtin_constant_p(n) && (n <= 8)) {
 366                 unsigned long ret = 1;
 367
 368                 switch (n) {
 369                 case 1:
 370                         __get_user_size(*(u8 *)to, from, 1, ret);
 371                         break;
 372                 case 2:
 373                         __get_user_size(*(u16 *)to, from, 2, ret);
 374                         break;
 375                 case 4:
 376                         __get_user_size(*(u32 *)to, from, 4, ret);
 377                         break;
 378                 case 8:
 379                         __get_user_size(*(u64 *)to, from, 8, ret);
 380                         break;
 381                 }
 382                 if (ret == 0)
 383                         return 0;
 384         }
 385
 386         if (!__builtin_constant_p(n))
 387                 check_object_size(to, n, false);
 388
 389         return __copy_tofrom_user((__force void __user *)to, from, n);
 390 }
 391
 392 static inline unsigned long __copy_to_user_inatomic(void __user *to,
 393                 const void *from, unsigned long n)
 394 {
 395         if (__builtin_constant_p(n) && (n <= 8)) {
 396                 unsigned long ret = 1;
 397
 398                 switch (n) {
 399                 case 1:
 400                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 401                         break;
 402                 case 2:
 403                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 404                         break;
 405                 case 4:
 406                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 407                         break;
 408                 case 8:
 409                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 410                         break;
 411                 }
 412                 if (ret == 0)
 413                         return 0;
 414         }
 415         if (!__builtin_constant_p(n))
 416                 check_object_size(from, n, true);
 417
 418         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 419 }
 420
 421 static inline unsigned long __copy_from_user(void *to,
 422                 const void __user *from, unsigned long size)
 423 {
 424         might_fault();
 425         return __copy_from_user_inatomic(to, from, size);
 426 }
 427
 428 static inline unsigned long __copy_to_user(void __user *to,
 429                 const void *from, unsigned long size)
 430 {
 431         might_fault();
 432         return __copy_to_user_inatomic(to, from, size);
 433 }
 434
 435 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 436
 437 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 438 {
 439         might_fault();
 440         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 441                 return __clear_user(addr, size);
 442         if ((unsigned long)addr < TASK_SIZE) {
 443                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 444                 return __clear_user(addr, size - over) + over;
 445         }
 446         return size;
 447 }
 448
 449 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 450 extern __must_check long strlen_user(const char __user *str);
 451 extern __must_check long strnlen_user(const char __user *str, long n);
 452
 453 #endif  /* __ASSEMBLY__ */
 454 #endif /* __KERNEL__ */
 455
 456 #endif  /* _ARCH_POWERPC_UACCESS_H */