include/asm-ppc/uaccess.h

   1 #ifdef __KERNEL__
   2 #ifndef _PPC_UACCESS_H
   3 #define _PPC_UACCESS_H
   4
   5 #ifndef __ASSEMBLY__
   6 #include <linux/sched.h>
   7 #include <linux/errno.h>
   8 #include <asm/processor.h>
   9
  10 #define VERIFY_READ     0
  11 #define VERIFY_WRITE    1
  12
  13 /*
  14  * The fs value determines whether argument validity checking should be
  15  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  16  * get_fs() == KERNEL_DS, checking is bypassed.
  17  *
  18  * For historical reasons, these macros are grossly misnamed.
  19  *
  20  * The fs/ds values are now the highest legal address in the "segment".
  21  * This simplifies the checking in the routines below.
  22  */
  23
  24 #define KERNEL_DS       ((mm_segment_t) { ~0UL })
  25 #define USER_DS         ((mm_segment_t) { TASK_SIZE - 1 })
  26
  27 #define get_ds()        (KERNEL_DS)
  28 #define get_fs()        (current->thread.fs)
  29 #define set_fs(val)     (current->thread.fs = (val))
  30
  31 #define segment_eq(a,b) ((a).seg == (b).seg)
  32
  33 #define __access_ok(addr,size)                                              \
  34         ((addr) <= current->thread.fs.seg                                   \
  35          && ((size) == 0 || (size) - 1 <= current->thread.fs.seg - (addr)))
  36
  37 #define access_ok(type, addr, size) \
  38         (__chk_user_ptr(addr),__access_ok((unsigned long)(addr),(size)))
  39
  40 /* this function will go away soon - use access_ok() instead */
  41 extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
  42 {
  43         return access_ok(type, addr, size) ? 0 : -EFAULT;
  44 }
  45
  46
  47 /*
  48  * The exception table consists of pairs of addresses: the first is the
  49  * address of an instruction that is allowed to fault, and the second is
  50  * the address at which the program should continue.  No registers are
  51  * modified, so it is entirely up to the continuation code to figure out
  52  * what to do.
  53  *
  54  * All the routines below use bits of fixup code that are out of line
  55  * with the main instruction path.  This means when everything is well,
  56  * we don't even have to jump over them.  Further, they do not intrude
  57  * on our cache or tlb entries.
  58  */
  59
  60 struct exception_table_entry
  61 {
  62         unsigned long insn, fixup;
  63 };
  64
  65 /*
  66  * These are the main single-value transfer routines.  They automatically
  67  * use the right size if we just have the right pointer type.
  68  *
  69  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  70  * and yet we don't want to do any pointers, because that is too much
  71  * of a performance impact. Thus we have a few rather ugly macros here,
  72  * and hide all the ugliness from the user.
  73  *
  74  * The "__xxx" versions of the user access functions are versions that
  75  * do not verify the address space, that must have been done previously
  76  * with a separate "access_ok()" call (this is used when we do multiple
  77  * accesses to the same area of user memory).
  78  *
  79  * As we use the same address space for kernel and user data on the
  80  * PowerPC, we can just do these as direct assignments.  (Of course, the
  81  * exception handling means that it's no longer "just"...)
  82  *
  83  * The "user64" versions of the user access functions are versions that
  84  * allow access of 64-bit data. The "get_user" functions do not
  85  * properly handle 64-bit data because the value gets down cast to a long.
  86  * The "put_user" functions already handle 64-bit data properly but we add
  87  * "user64" versions for completeness
  88  */
  89 #define get_user(x,ptr) \
  90   __get_user_check((x),(ptr),sizeof(*(ptr)))
  91 #define get_user64(x,ptr) \
  92   __get_user64_check((x),(ptr),sizeof(*(ptr)))
  93 #define put_user(x,ptr) \
  94   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  95 #define put_user64(x,ptr) put_user(x,ptr)
  96
  97 #define __get_user(x,ptr) \
  98   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  99 #define __get_user64(x,ptr) \
 100   __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
 101 #define __put_user(x,ptr) \
 102   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
 103 #define __put_user64(x,ptr) __put_user(x,ptr)
 104
 105 extern long __put_user_bad(void);
 106
 107 #define __put_user_nocheck(x,ptr,size)                  \
 108 ({                                                      \
 109         long __pu_err;                                  \
 110         __chk_user_ptr(ptr);                            \
 111         __put_user_size((x),(ptr),(size),__pu_err);     \
 112         __pu_err;                                       \
 113 })
 114
 115 #define __put_user_check(x,ptr,size)                            \
 116 ({                                                              \
 117         long __pu_err = -EFAULT;                                \
 118         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 119         if (access_ok(VERIFY_WRITE,__pu_addr,size))             \
 120                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 121         __pu_err;                                               \
 122 })
 123
 124 #define __put_user_size(x,ptr,size,retval)              \
 125 do {                                                    \
 126         retval = 0;                                     \
 127         switch (size) {                                 \
 128         case 1:                                         \
 129                 __put_user_asm(x, ptr, retval, "stb");  \
 130                 break;                                  \
 131         case 2:                                         \
 132                 __put_user_asm(x, ptr, retval, "sth");  \
 133                 break;                                  \
 134         case 4:                                         \
 135                 __put_user_asm(x, ptr, retval, "stw");  \
 136                 break;                                  \
 137         case 8:                                         \
 138                 __put_user_asm2(x, ptr, retval);        \
 139                 break;                                  \
 140         default:                                        \
 141                 __put_user_bad();                       \
 142         }                                               \
 143 } while (0)
 144
 145 /*
 146  * We don't tell gcc that we are accessing memory, but this is OK
 147  * because we do not write to any memory gcc knows about, so there
 148  * are no aliasing issues.
 149  */
 150 #define __put_user_asm(x, addr, err, op)                        \
 151         __asm__ __volatile__(                                   \
 152                 "1:     "op" %1,0(%2)\n"                        \
 153                 "2:\n"                                          \
 154                 ".section .fixup,\"ax\"\n"                      \
 155                 "3:     li %0,%3\n"                             \
 156                 "       b 2b\n"                                 \
 157                 ".previous\n"                                   \
 158                 ".section __ex_table,\"a\"\n"                   \
 159                 "       .align 2\n"                             \
 160                 "       .long 1b,3b\n"                          \
 161                 ".previous"                                     \
 162                 : "=r" (err)                                    \
 163                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 164
 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 2\n"                             \
 176                 "       .long 1b,4b\n"                          \
 177                 "       .long 2b,4b\n"                          \
 178                 ".previous"                                     \
 179                 : "=r" (err)                                    \
 180                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 181
 182 #define __get_user_nocheck(x, ptr, size)                        \
 183 ({                                                              \
 184         long __gu_err;                                          \
 185         unsigned long __gu_val;                                 \
 186         __chk_user_ptr(ptr);                                    \
 187         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 188         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 189         __gu_err;                                               \
 190 })
 191
 192 #define __get_user64_nocheck(x, ptr, size)                      \
 193 ({                                                              \
 194         long __gu_err;                                          \
 195         long long __gu_val;                                     \
 196         __chk_user_ptr(ptr);                                    \
 197         __get_user_size64(__gu_val, (ptr), (size), __gu_err);   \
 198         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 199         __gu_err;                                               \
 200 })
 201
 202 #define __get_user_check(x, ptr, size)                                  \
 203 ({                                                                      \
 204         long __gu_err = -EFAULT;                                        \
 205         unsigned long  __gu_val = 0;                                    \
 206         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 207         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 208                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 209         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 210         __gu_err;                                                       \
 211 })
 212
 213 #define __get_user64_check(x, ptr, size)                                  \
 214 ({                                                                        \
 215         long __gu_err = -EFAULT;                                          \
 216         long long __gu_val = 0;                                           \
 217         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);               \
 218         if (access_ok(VERIFY_READ, __gu_addr, (size)))                    \
 219                 __get_user_size64(__gu_val, __gu_addr, (size), __gu_err); \
 220         (x) = (__typeof__(*(ptr)))__gu_val;                               \
 221         __gu_err;                                                         \
 222 })
 223
 224 extern long __get_user_bad(void);
 225
 226 #define __get_user_size(x, ptr, size, retval)                   \
 227 do {                                                            \
 228         retval = 0;                                             \
 229         switch (size) {                                         \
 230         case 1:                                                 \
 231                 __get_user_asm(x, ptr, retval, "lbz");          \
 232                 break;                                          \
 233         case 2:                                                 \
 234                 __get_user_asm(x, ptr, retval, "lhz");          \
 235                 break;                                          \
 236         case 4:                                                 \
 237                 __get_user_asm(x, ptr, retval, "lwz");          \
 238                 break;                                          \
 239         default:                                                \
 240                 x = __get_user_bad();                           \
 241         }                                                       \
 242 } while (0)
 243
 244 #define __get_user_size64(x, ptr, size, retval)                 \
 245 do {                                                            \
 246         retval = 0;                                             \
 247         switch (size) {                                         \
 248         case 1:                                                 \
 249                 __get_user_asm(x, ptr, retval, "lbz");          \
 250                 break;                                          \
 251         case 2:                                                 \
 252                 __get_user_asm(x, ptr, retval, "lhz");          \
 253                 break;                                          \
 254         case 4:                                                 \
 255                 __get_user_asm(x, ptr, retval, "lwz");          \
 256                 break;                                          \
 257         case 8:                                                 \
 258                 __get_user_asm2(x, ptr, retval);                \
 259                 break;                                          \
 260         default:                                                \
 261                 x = __get_user_bad();                           \
 262         }                                                       \
 263 } while (0)
 264
 265 #define __get_user_asm(x, addr, err, op)                \
 266         __asm__ __volatile__(                           \
 267                 "1:     "op" %1,0(%2)\n"                \
 268                 "2:\n"                                  \
 269                 ".section .fixup,\"ax\"\n"              \
 270                 "3:     li %0,%3\n"                     \
 271                 "       li %1,0\n"                      \
 272                 "       b 2b\n"                         \
 273                 ".previous\n"                           \
 274                 ".section __ex_table,\"a\"\n"           \
 275                 "       .align 2\n"                     \
 276                 "       .long 1b,3b\n"                  \
 277                 ".previous"                             \
 278                 : "=r"(err), "=r"(x)                    \
 279                 : "b"(addr), "i"(-EFAULT), "0"(err))
 280
 281 #define __get_user_asm2(x, addr, err)                   \
 282         __asm__ __volatile__(                           \
 283                 "1:     lwz %1,0(%2)\n"                 \
 284                 "2:     lwz %1+1,4(%2)\n"               \
 285                 "3:\n"                                  \
 286                 ".section .fixup,\"ax\"\n"              \
 287                 "4:     li %0,%3\n"                     \
 288                 "       li %1,0\n"                      \
 289                 "       li %1+1,0\n"                    \
 290                 "       b 3b\n"                         \
 291                 ".previous\n"                           \
 292                 ".section __ex_table,\"a\"\n"           \
 293                 "       .align 2\n"                     \
 294                 "       .long 1b,4b\n"                  \
 295                 "       .long 2b,4b\n"                  \
 296                 ".previous"                             \
 297                 : "=r"(err), "=&r"(x)                   \
 298                 : "b"(addr), "i"(-EFAULT), "0"(err))
 299
 300 /* more complex routines */
 301
 302 extern int __copy_tofrom_user(void __user *to, const void __user *from,
 303                               unsigned long size);
 304
 305 extern inline unsigned long
 306 copy_from_user(void *to, const void __user *from, unsigned long n)
 307 {
 308         unsigned long over;
 309
 310         if (access_ok(VERIFY_READ, from, n))
 311                 return __copy_tofrom_user((__force void __user *)to, from, n);
 312         if ((unsigned long)from < TASK_SIZE) {
 313                 over = (unsigned long)from + n - TASK_SIZE;
 314                 return __copy_tofrom_user((__force void __user *)to, from, n - over) + over;
 315         }
 316         return n;
 317 }
 318
 319 extern inline unsigned long
 320 copy_to_user(void __user *to, const void *from, unsigned long n)
 321 {
 322         unsigned long over;
 323
 324         if (access_ok(VERIFY_WRITE, to, n))
 325                 return __copy_tofrom_user(to, (__force void __user *) from, n);
 326         if ((unsigned long)to < TASK_SIZE) {
 327                 over = (unsigned long)to + n - TASK_SIZE;
 328                 return __copy_tofrom_user(to, (__force void __user *) from, n - over) + over;
 329         }
 330         return n;
 331 }
 332
 333 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long size)
 334 {
 335         return __copy_tofrom_user((__force void __user *)to, from, size);
 336 }
 337
 338 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long size)
 339 {
 340         return __copy_tofrom_user(to, (__force void __user *)from, size);
 341 }
 342
 343 #define __copy_to_user_inatomic __copy_to_user
 344 #define __copy_from_user_inatomic __copy_from_user
 345
 346 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 347
 348 extern inline unsigned long
 349 clear_user(void __user *addr, unsigned long size)
 350 {
 351         if (access_ok(VERIFY_WRITE, addr, size))
 352                 return __clear_user(addr, size);
 353         if ((unsigned long)addr < TASK_SIZE) {
 354                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 355                 return __clear_user(addr, size - over) + over;
 356         }
 357         return size;
 358 }
 359
 360 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 361
 362 extern inline long
 363 strncpy_from_user(char *dst, const char __user *src, long count)
 364 {
 365         if (access_ok(VERIFY_READ, src, 1))
 366                 return __strncpy_from_user(dst, src, count);
 367         return -EFAULT;
 368 }
 369
 370 /*
 371  * Return the size of a string (including the ending 0)
 372  *
 373  * Return 0 for error
 374  */
 375
 376 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 377
 378 /*
 379  * Returns the length of the string at str (including the null byte),
 380  * or 0 if we hit a page we can't access,
 381  * or something > len if we didn't find a null byte.
 382  *
 383  * The `top' parameter to __strnlen_user is to make sure that
 384  * we can never overflow from the user area into kernel space.
 385  */
 386 extern __inline__ int strnlen_user(const char __user *str, long len)
 387 {
 388         unsigned long top = current->thread.fs.seg;
 389
 390         if ((unsigned long)str > top)
 391                 return 0;
 392         return __strnlen_user(str, len, top);
 393 }
 394
 395 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 396
 397 #endif  /* __ASSEMBLY__ */
 398
 399 #endif  /* _PPC_UACCESS_H */
 400 #endif /* __KERNEL__ */