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 /*
  41  * The exception table consists of pairs of addresses: the first is the
  42  * address of an instruction that is allowed to fault, and the second is
  43  * the address at which the program should continue.  No registers are
  44  * modified, so it is entirely up to the continuation code to figure out
  45  * what to do.
  46  *
  47  * All the routines below use bits of fixup code that are out of line
  48  * with the main instruction path.  This means when everything is well,
  49  * we don't even have to jump over them.  Further, they do not intrude
  50  * on our cache or tlb entries.
  51  */
  52
  53 struct exception_table_entry
  54 {
  55         unsigned long insn, fixup;
  56 };
  57
  58 /*
  59  * These are the main single-value transfer routines.  They automatically
  60  * use the right size if we just have the right pointer type.
  61  *
  62  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  63  * and yet we don't want to do any pointers, because that is too much
  64  * of a performance impact. Thus we have a few rather ugly macros here,
  65  * and hide all the ugliness from the user.
  66  *
  67  * The "__xxx" versions of the user access functions are versions that
  68  * do not verify the address space, that must have been done previously
  69  * with a separate "access_ok()" call (this is used when we do multiple
  70  * accesses to the same area of user memory).
  71  *
  72  * As we use the same address space for kernel and user data on the
  73  * PowerPC, we can just do these as direct assignments.  (Of course, the
  74  * exception handling means that it's no longer "just"...)
  75  *
  76  * The "user64" versions of the user access functions are versions that
  77  * allow access of 64-bit data. The "get_user" functions do not
  78  * properly handle 64-bit data because the value gets down cast to a long.
  79  * The "put_user" functions already handle 64-bit data properly but we add
  80  * "user64" versions for completeness
  81  */
  82 #define get_user(x,ptr) \
  83   __get_user_check((x),(ptr),sizeof(*(ptr)))
  84 #define get_user64(x,ptr) \
  85   __get_user64_check((x),(ptr),sizeof(*(ptr)))
  86 #define put_user(x,ptr) \
  87   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  88 #define put_user64(x,ptr) put_user(x,ptr)
  89
  90 #define __get_user(x,ptr) \
  91   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  92 #define __get_user64(x,ptr) \
  93   __get_user64_nocheck((x),(ptr),sizeof(*(ptr)))
  94 #define __put_user(x,ptr) \
  95   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  96 #define __put_user64(x,ptr) __put_user(x,ptr)
  97
  98 extern long __put_user_bad(void);
  99
 100 #define __put_user_nocheck(x,ptr,size)                  \
 101 ({                                                      \
 102         long __pu_err;                                  \
 103         __chk_user_ptr(ptr);                            \
 104         __put_user_size((x),(ptr),(size),__pu_err);     \
 105         __pu_err;                                       \
 106 })
 107
 108 #define __put_user_check(x,ptr,size)                            \
 109 ({                                                              \
 110         long __pu_err = -EFAULT;                                \
 111         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 112         if (access_ok(VERIFY_WRITE,__pu_addr,size))             \
 113                 __put_user_size((x),__pu_addr,(size),__pu_err); \
 114         __pu_err;                                               \
 115 })
 116
 117 #define __put_user_size(x,ptr,size,retval)              \
 118 do {                                                    \
 119         retval = 0;                                     \
 120         switch (size) {                                 \
 121         case 1:                                         \
 122                 __put_user_asm(x, ptr, retval, "stb");  \
 123                 break;                                  \
 124         case 2:                                         \
 125                 __put_user_asm(x, ptr, retval, "sth");  \
 126                 break;                                  \
 127         case 4:                                         \
 128                 __put_user_asm(x, ptr, retval, "stw");  \
 129                 break;                                  \
 130         case 8:                                         \
 131                 __put_user_asm2(x, ptr, retval);        \
 132                 break;                                  \
 133         default:                                        \
 134                 __put_user_bad();                       \
 135         }                                               \
 136 } while (0)
 137
 138 /*
 139  * We don't tell gcc that we are accessing memory, but this is OK
 140  * because we do not write to any memory gcc knows about, so there
 141  * are no aliasing issues.
 142  */
 143 #define __put_user_asm(x, addr, err, op)                        \
 144         __asm__ __volatile__(                                   \
 145                 "1:     "op" %1,0(%2)\n"                        \
 146                 "2:\n"                                          \
 147                 ".section .fixup,\"ax\"\n"                      \
 148                 "3:     li %0,%3\n"                             \
 149                 "       b 2b\n"                                 \
 150                 ".previous\n"                                   \
 151                 ".section __ex_table,\"a\"\n"                   \
 152                 "       .align 2\n"                             \
 153                 "       .long 1b,3b\n"                          \
 154                 ".previous"                                     \
 155                 : "=r" (err)                                    \
 156                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 157
 158 #define __put_user_asm2(x, addr, err)                           \
 159         __asm__ __volatile__(                                   \
 160                 "1:     stw %1,0(%2)\n"                         \
 161                 "2:     stw %1+1,4(%2)\n"                       \
 162                 "3:\n"                                          \
 163                 ".section .fixup,\"ax\"\n"                      \
 164                 "4:     li %0,%3\n"                             \
 165                 "       b 3b\n"                                 \
 166                 ".previous\n"                                   \
 167                 ".section __ex_table,\"a\"\n"                   \
 168                 "       .align 2\n"                             \
 169                 "       .long 1b,4b\n"                          \
 170                 "       .long 2b,4b\n"                          \
 171                 ".previous"                                     \
 172                 : "=r" (err)                                    \
 173                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 174
 175 #define __get_user_nocheck(x, ptr, size)                        \
 176 ({                                                              \
 177         long __gu_err;                                          \
 178         unsigned long __gu_val;                                 \
 179         __chk_user_ptr(ptr);                                    \
 180         __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 181         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 182         __gu_err;                                               \
 183 })
 184
 185 #define __get_user64_nocheck(x, ptr, size)                      \
 186 ({                                                              \
 187         long __gu_err;                                          \
 188         long long __gu_val;                                     \
 189         __chk_user_ptr(ptr);                                    \
 190         __get_user_size64(__gu_val, (ptr), (size), __gu_err);   \
 191         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 192         __gu_err;                                               \
 193 })
 194
 195 #define __get_user_check(x, ptr, size)                                  \
 196 ({                                                                      \
 197         long __gu_err = -EFAULT;                                        \
 198         unsigned long  __gu_val = 0;                                    \
 199         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 200         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 201                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 202         (x) = (__typeof__(*(ptr)))__gu_val;                             \
 203         __gu_err;                                                       \
 204 })
 205
 206 #define __get_user64_check(x, ptr, size)                                  \
 207 ({                                                                        \
 208         long __gu_err = -EFAULT;                                          \
 209         long long __gu_val = 0;                                           \
 210         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);               \
 211         if (access_ok(VERIFY_READ, __gu_addr, (size)))                    \
 212                 __get_user_size64(__gu_val, __gu_addr, (size), __gu_err); \
 213         (x) = (__typeof__(*(ptr)))__gu_val;                               \
 214         __gu_err;                                                         \
 215 })
 216
 217 extern long __get_user_bad(void);
 218
 219 #define __get_user_size(x, ptr, size, retval)                   \
 220 do {                                                            \
 221         retval = 0;                                             \
 222         switch (size) {                                         \
 223         case 1:                                                 \
 224                 __get_user_asm(x, ptr, retval, "lbz");          \
 225                 break;                                          \
 226         case 2:                                                 \
 227                 __get_user_asm(x, ptr, retval, "lhz");          \
 228                 break;                                          \
 229         case 4:                                                 \
 230                 __get_user_asm(x, ptr, retval, "lwz");          \
 231                 break;                                          \
 232         default:                                                \
 233                 x = __get_user_bad();                           \
 234         }                                                       \
 235 } while (0)
 236
 237 #define __get_user_size64(x, ptr, size, retval)                 \
 238 do {                                                            \
 239         retval = 0;                                             \
 240         switch (size) {                                         \
 241         case 1:                                                 \
 242                 __get_user_asm(x, ptr, retval, "lbz");          \
 243                 break;                                          \
 244         case 2:                                                 \
 245                 __get_user_asm(x, ptr, retval, "lhz");          \
 246                 break;                                          \
 247         case 4:                                                 \
 248                 __get_user_asm(x, ptr, retval, "lwz");          \
 249                 break;                                          \
 250         case 8:                                                 \
 251                 __get_user_asm2(x, ptr, retval);                \
 252                 break;                                          \
 253         default:                                                \
 254                 x = __get_user_bad();                           \
 255         }                                                       \
 256 } while (0)
 257
 258 #define __get_user_asm(x, addr, err, op)                \
 259         __asm__ __volatile__(                           \
 260                 "1:     "op" %1,0(%2)\n"                \
 261                 "2:\n"                                  \
 262                 ".section .fixup,\"ax\"\n"              \
 263                 "3:     li %0,%3\n"                     \
 264                 "       li %1,0\n"                      \
 265                 "       b 2b\n"                         \
 266                 ".previous\n"                           \
 267                 ".section __ex_table,\"a\"\n"           \
 268                 "       .align 2\n"                     \
 269                 "       .long 1b,3b\n"                  \
 270                 ".previous"                             \
 271                 : "=r"(err), "=r"(x)                    \
 272                 : "b"(addr), "i"(-EFAULT), "0"(err))
 273
 274 #define __get_user_asm2(x, addr, err)                   \
 275         __asm__ __volatile__(                           \
 276                 "1:     lwz %1,0(%2)\n"                 \
 277                 "2:     lwz %1+1,4(%2)\n"               \
 278                 "3:\n"                                  \
 279                 ".section .fixup,\"ax\"\n"              \
 280                 "4:     li %0,%3\n"                     \
 281                 "       li %1,0\n"                      \
 282                 "       li %1+1,0\n"                    \
 283                 "       b 3b\n"                         \
 284                 ".previous\n"                           \
 285                 ".section __ex_table,\"a\"\n"           \
 286                 "       .align 2\n"                     \
 287                 "       .long 1b,4b\n"                  \
 288                 "       .long 2b,4b\n"                  \
 289                 ".previous"                             \
 290                 : "=r"(err), "=&r"(x)                   \
 291                 : "b"(addr), "i"(-EFAULT), "0"(err))
 292
 293 /* more complex routines */
 294
 295 extern int __copy_tofrom_user(void __user *to, const void __user *from,
 296                               unsigned long size);
 297
 298 extern inline unsigned long
 299 copy_from_user(void *to, const void __user *from, unsigned long n)
 300 {
 301         unsigned long over;
 302
 303         if (access_ok(VERIFY_READ, from, n))
 304                 return __copy_tofrom_user((__force void __user *)to, from, n);
 305         if ((unsigned long)from < TASK_SIZE) {
 306                 over = (unsigned long)from + n - TASK_SIZE;
 307                 return __copy_tofrom_user((__force void __user *)to, from, n - over) + over;
 308         }
 309         return n;
 310 }
 311
 312 extern inline unsigned long
 313 copy_to_user(void __user *to, const void *from, unsigned long n)
 314 {
 315         unsigned long over;
 316
 317         if (access_ok(VERIFY_WRITE, to, n))
 318                 return __copy_tofrom_user(to, (__force void __user *) from, n);
 319         if ((unsigned long)to < TASK_SIZE) {
 320                 over = (unsigned long)to + n - TASK_SIZE;
 321                 return __copy_tofrom_user(to, (__force void __user *) from, n - over) + over;
 322         }
 323         return n;
 324 }
 325
 326 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long size)
 327 {
 328         return __copy_tofrom_user((__force void __user *)to, from, size);
 329 }
 330
 331 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long size)
 332 {
 333         return __copy_tofrom_user(to, (__force void __user *)from, size);
 334 }
 335
 336 #define __copy_to_user_inatomic __copy_to_user
 337 #define __copy_from_user_inatomic __copy_from_user
 338
 339 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 340
 341 extern inline unsigned long
 342 clear_user(void __user *addr, unsigned long size)
 343 {
 344         if (access_ok(VERIFY_WRITE, addr, size))
 345                 return __clear_user(addr, size);
 346         if ((unsigned long)addr < TASK_SIZE) {
 347                 unsigned long over = (unsigned long)addr + size - TASK_SIZE;
 348                 return __clear_user(addr, size - over) + over;
 349         }
 350         return size;
 351 }
 352
 353 extern int __strncpy_from_user(char *dst, const char __user *src, long count);
 354
 355 extern inline long
 356 strncpy_from_user(char *dst, const char __user *src, long count)
 357 {
 358         if (access_ok(VERIFY_READ, src, 1))
 359                 return __strncpy_from_user(dst, src, count);
 360         return -EFAULT;
 361 }
 362
 363 /*
 364  * Return the size of a string (including the ending 0)
 365  *
 366  * Return 0 for error
 367  */
 368
 369 extern int __strnlen_user(const char __user *str, long len, unsigned long top);
 370
 371 /*
 372  * Returns the length of the string at str (including the null byte),
 373  * or 0 if we hit a page we can't access,
 374  * or something > len if we didn't find a null byte.
 375  *
 376  * The `top' parameter to __strnlen_user is to make sure that
 377  * we can never overflow from the user area into kernel space.
 378  */
 379 extern __inline__ int strnlen_user(const char __user *str, long len)
 380 {
 381         unsigned long top = current->thread.fs.seg;
 382
 383         if ((unsigned long)str > top)
 384                 return 0;
 385         return __strnlen_user(str, len, top);
 386 }
 387
 388 #define strlen_user(str)        strnlen_user((str), 0x7ffffffe)
 389
 390 #endif  /* __ASSEMBLY__ */
 391
 392 #endif  /* _PPC_UACCESS_H */
 393 #endif /* __KERNEL__ */