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/ppc_asm.h>
  11 #include <asm/processor.h>
  12 #include <asm/page.h>
  13
  14 #define VERIFY_READ     0
  15 #define VERIFY_WRITE    1
  16
  17 /*
  18  * The fs value determines whether argument validity checking should be
  19  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  20  * get_fs() == KERNEL_DS, checking is bypassed.
  21  *
  22  * For historical reasons, these macros are grossly misnamed.
  23  *
  24  * The fs/ds values are now the highest legal address in the "segment".
  25  * This simplifies the checking in the routines below.
  26  */
  27
  28 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  29
  30 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  31 #ifdef __powerpc64__
  32 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  33 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  34 #else
  35 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  36 #endif
  37
  38 #define get_ds()        (KERNEL_DS)
  39 #define get_fs()        (current->thread.fs)
  40 #define set_fs(val)     (current->thread.fs = (val))
  41
  42 #define segment_eq(a, b)        ((a).seg == (b).seg)
  43
  44 #define user_addr_max() (get_fs().seg)
  45
  46 #ifdef __powerpc64__
  47 /*
  48  * This check is sufficient because there is a large enough
  49  * gap between user addresses and the kernel addresses
  50  */
  51 #define __access_ok(addr, size, segment)        \
  52         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  53
  54 #else
  55
  56 #define __access_ok(addr, size, segment)        \
  57         (((addr) <= (segment).seg) &&           \
  58          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  59
  60 #endif
  61
  62 #define access_ok(type, addr, size)             \
  63         (__chk_user_ptr(addr),                  \
  64          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  65
  66 /*
  67  * The exception table consists of pairs of relative addresses: the first is
  68  * the address of an instruction that is allowed to fault, and the second is
  69  * the address at which the program should continue.  No registers are
  70  * modified, so it is entirely up to the continuation code to figure out what
  71  * to do.
  72  *
  73  * All the routines below use bits of fixup code that are out of line with the
  74  * main instruction path.  This means when everything is well, we don't even
  75  * have to jump over them.  Further, they do not intrude on our cache or tlb
  76  * entries.
  77  */
  78
  79 #define ARCH_HAS_RELATIVE_EXTABLE
  80
  81 struct exception_table_entry {
  82         int insn;
  83         int fixup;
  84 };
  85
  86 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  87 {
  88         return (unsigned long)&x->fixup + x->fixup;
  89 }
  90
  91 /*
  92  * These are the main single-value transfer routines.  They automatically
  93  * use the right size if we just have the right pointer type.
  94  *
  95  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  96  * and yet we don't want to do any pointers, because that is too much
  97  * of a performance impact. Thus we have a few rather ugly macros here,
  98  * and hide all the ugliness from the user.
  99  *
 100  * The "__xxx" versions of the user access functions are versions that
 101  * do not verify the address space, that must have been done previously
 102  * with a separate "access_ok()" call (this is used when we do multiple
 103  * accesses to the same area of user memory).
 104  *
 105  * As we use the same address space for kernel and user data on the
 106  * PowerPC, we can just do these as direct assignments.  (Of course, the
 107  * exception handling means that it's no longer "just"...)
 108  *
 109  */
 110 #define get_user(x, ptr) \
 111         __get_user_check((x), (ptr), sizeof(*(ptr)))
 112 #define put_user(x, ptr) \
 113         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 114
 115 #define __get_user(x, ptr) \
 116         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 117 #define __put_user(x, ptr) \
 118         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 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                 EX_TABLE(1b, 3b)                                \
 144                 : "=r" (err)                                    \
 145                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 146
 147 #ifdef __powerpc64__
 148 #define __put_user_asm2(x, ptr, retval)                         \
 149           __put_user_asm(x, ptr, retval, "std")
 150 #else /* __powerpc64__ */
 151 #define __put_user_asm2(x, addr, err)                           \
 152         __asm__ __volatile__(                                   \
 153                 "1:     stw %1,0(%2)\n"                         \
 154                 "2:     stw %1+1,4(%2)\n"                       \
 155                 "3:\n"                                          \
 156                 ".section .fixup,\"ax\"\n"                      \
 157                 "4:     li %0,%3\n"                             \
 158                 "       b 3b\n"                                 \
 159                 ".previous\n"                                   \
 160                 EX_TABLE(1b, 4b)                                \
 161                 EX_TABLE(2b, 4b)                                \
 162                 : "=r" (err)                                    \
 163                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 164 #endif /* __powerpc64__ */
 165
 166 #define __put_user_size(x, ptr, size, retval)                   \
 167 do {                                                            \
 168         retval = 0;                                             \
 169         switch (size) {                                         \
 170           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 171           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 172           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 173           case 8: __put_user_asm2(x, ptr, retval); break;       \
 174           default: __put_user_bad();                            \
 175         }                                                       \
 176 } while (0)
 177
 178 #define __put_user_nocheck(x, ptr, size)                        \
 179 ({                                                              \
 180         long __pu_err;                                          \
 181         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 182         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 183                 might_fault();                                  \
 184         __chk_user_ptr(ptr);                                    \
 185         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 186         __pu_err;                                               \
 187 })
 188
 189 #define __put_user_check(x, ptr, size)                                  \
 190 ({                                                                      \
 191         long __pu_err = -EFAULT;                                        \
 192         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 193         might_fault();                                                  \
 194         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 195                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 196         __pu_err;                                                       \
 197 })
 198
 199 #define __put_user_nosleep(x, ptr, size)                        \
 200 ({                                                              \
 201         long __pu_err;                                          \
 202         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 203         __chk_user_ptr(ptr);                                    \
 204         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 205         __pu_err;                                               \
 206 })
 207
 208
 209 extern long __get_user_bad(void);
 210
 211 #define __get_user_asm(x, addr, err, op)                \
 212         __asm__ __volatile__(                           \
 213                 "1:     "op" %1,0(%2)   # get_user\n"   \
 214                 "2:\n"                                  \
 215                 ".section .fixup,\"ax\"\n"              \
 216                 "3:     li %0,%3\n"                     \
 217                 "       li %1,0\n"                      \
 218                 "       b 2b\n"                         \
 219                 ".previous\n"                           \
 220                 EX_TABLE(1b, 3b)                        \
 221                 : "=r" (err), "=r" (x)                  \
 222                 : "b" (addr), "i" (-EFAULT), "0" (err))
 223
 224 #ifdef __powerpc64__
 225 #define __get_user_asm2(x, addr, err)                   \
 226         __get_user_asm(x, addr, err, "ld")
 227 #else /* __powerpc64__ */
 228 #define __get_user_asm2(x, addr, err)                   \
 229         __asm__ __volatile__(                           \
 230                 "1:     lwz %1,0(%2)\n"                 \
 231                 "2:     lwz %1+1,4(%2)\n"               \
 232                 "3:\n"                                  \
 233                 ".section .fixup,\"ax\"\n"              \
 234                 "4:     li %0,%3\n"                     \
 235                 "       li %1,0\n"                      \
 236                 "       li %1+1,0\n"                    \
 237                 "       b 3b\n"                         \
 238                 ".previous\n"                           \
 239                 EX_TABLE(1b, 4b)                        \
 240                 EX_TABLE(2b, 4b)                        \
 241                 : "=r" (err), "=&r" (x)                 \
 242                 : "b" (addr), "i" (-EFAULT), "0" (err))
 243 #endif /* __powerpc64__ */
 244
 245 #define __get_user_size(x, ptr, size, retval)                   \
 246 do {                                                            \
 247         retval = 0;                                             \
 248         __chk_user_ptr(ptr);                                    \
 249         if (size > sizeof(x))                                   \
 250                 (x) = __get_user_bad();                         \
 251         switch (size) {                                         \
 252         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 253         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 254         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 255         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 256         default: (x) = __get_user_bad();                        \
 257         }                                                       \
 258 } while (0)
 259
 260 #define __get_user_nocheck(x, ptr, size)                        \
 261 ({                                                              \
 262         long __gu_err;                                          \
 263         unsigned long __gu_val;                                 \
 264         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 265         __chk_user_ptr(ptr);                                    \
 266         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 267                 might_fault();                                  \
 268         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 269         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 270         __gu_err;                                               \
 271 })
 272
 273 #define __get_user_check(x, ptr, size)                                  \
 274 ({                                                                      \
 275         long __gu_err = -EFAULT;                                        \
 276         unsigned long  __gu_val = 0;                                    \
 277         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 278         might_fault();                                                  \
 279         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 280                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 281         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 282         __gu_err;                                                       \
 283 })
 284
 285 #define __get_user_nosleep(x, ptr, size)                        \
 286 ({                                                              \
 287         long __gu_err;                                          \
 288         unsigned long __gu_val;                                 \
 289         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 290         __chk_user_ptr(ptr);                                    \
 291         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 292         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 293         __gu_err;                                               \
 294 })
 295
 296
 297 /* more complex routines */
 298
 299 extern unsigned long __copy_tofrom_user(void __user *to,
 300                 const void __user *from, unsigned long size);
 301
 302 #ifndef __powerpc64__
 303
 304 static inline unsigned long copy_from_user(void *to,
 305                 const void __user *from, unsigned long n)
 306 {
 307         if (likely(access_ok(VERIFY_READ, from, n))) {
 308                 check_object_size(to, n, false);
 309                 return __copy_tofrom_user((__force void __user *)to, from, n);
 310         }
 311         memset(to, 0, n);
 312         return n;
 313 }
 314
 315 static inline unsigned long copy_to_user(void __user *to,
 316                 const void *from, unsigned long n)
 317 {
 318         if (access_ok(VERIFY_WRITE, to, n)) {
 319                 check_object_size(from, n, true);
 320                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 321         }
 322         return n;
 323 }
 324
 325 #else /* __powerpc64__ */
 326
 327 #define __copy_in_user(to, from, size) \
 328         __copy_tofrom_user((to), (from), (size))
 329
 330 extern unsigned long copy_from_user(void *to, const void __user *from,
 331                                     unsigned long n);
 332 extern unsigned long copy_to_user(void __user *to, const void *from,
 333                                   unsigned long n);
 334 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 335                                   unsigned long n);
 336
 337 #endif /* __powerpc64__ */
 338
 339 static inline unsigned long __copy_from_user_inatomic(void *to,
 340                 const void __user *from, unsigned long n)
 341 {
 342         if (__builtin_constant_p(n) && (n <= 8)) {
 343                 unsigned long ret = 1;
 344
 345                 switch (n) {
 346                 case 1:
 347                         __get_user_size(*(u8 *)to, from, 1, ret);
 348                         break;
 349                 case 2:
 350                         __get_user_size(*(u16 *)to, from, 2, ret);
 351                         break;
 352                 case 4:
 353                         __get_user_size(*(u32 *)to, from, 4, ret);
 354                         break;
 355                 case 8:
 356                         __get_user_size(*(u64 *)to, from, 8, ret);
 357                         break;
 358                 }
 359                 if (ret == 0)
 360                         return 0;
 361         }
 362
 363         check_object_size(to, n, false);
 364
 365         return __copy_tofrom_user((__force void __user *)to, from, n);
 366 }
 367
 368 static inline unsigned long __copy_to_user_inatomic(void __user *to,
 369                 const void *from, unsigned long n)
 370 {
 371         if (__builtin_constant_p(n) && (n <= 8)) {
 372                 unsigned long ret = 1;
 373
 374                 switch (n) {
 375                 case 1:
 376                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 377                         break;
 378                 case 2:
 379                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 380                         break;
 381                 case 4:
 382                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 383                         break;
 384                 case 8:
 385                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 386                         break;
 387                 }
 388                 if (ret == 0)
 389                         return 0;
 390         }
 391
 392         check_object_size(from, n, true);
 393
 394         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 395 }
 396
 397 static inline unsigned long __copy_from_user(void *to,
 398                 const void __user *from, unsigned long size)
 399 {
 400         might_fault();
 401         return __copy_from_user_inatomic(to, from, size);
 402 }
 403
 404 static inline unsigned long __copy_to_user(void __user *to,
 405                 const void *from, unsigned long size)
 406 {
 407         might_fault();
 408         return __copy_to_user_inatomic(to, from, size);
 409 }
 410
 411 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 412
 413 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 414 {
 415         might_fault();
 416         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 417                 return __clear_user(addr, size);
 418         return size;
 419 }
 420
 421 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 422 extern __must_check long strlen_user(const char __user *str);
 423 extern __must_check long strnlen_user(const char __user *str, long n);
 424
 425 #endif  /* __ASSEMBLY__ */
 426 #endif /* __KERNEL__ */
 427
 428 #endif  /* _ARCH_POWERPC_UACCESS_H */