include/asm-alpha/uaccess.h

   1 #ifndef __ALPHA_UACCESS_H
   2 #define __ALPHA_UACCESS_H
   3
   4 #include <linux/errno.h>
   5 #include <linux/sched.h>
   6
   7
   8 /*
   9  * The fs value determines whether argument validity checking should be
  10  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  11  * get_fs() == KERNEL_DS, checking is bypassed.
  12  *
  13  * Or at least it did once upon a time.  Nowadays it is a mask that
  14  * defines which bits of the address space are off limits.  This is a
  15  * wee bit faster than the above.
  16  *
  17  * For historical reasons, these macros are grossly misnamed.
  18  */
  19
  20 #define KERNEL_DS       ((mm_segment_t) { 0UL })
  21 #define USER_DS         ((mm_segment_t) { -0x40000000000UL })
  22
  23 #define VERIFY_READ     0
  24 #define VERIFY_WRITE    1
  25
  26 #define get_fs()  (current_thread_info()->addr_limit)
  27 #define get_ds()  (KERNEL_DS)
  28 #define set_fs(x) (current_thread_info()->addr_limit = (x))
  29
  30 #define segment_eq(a,b) ((a).seg == (b).seg)
  31
  32 /*
  33  * Is a address valid? This does a straightforward calculation rather
  34  * than tests.
  35  *
  36  * Address valid if:
  37  *  - "addr" doesn't have any high-bits set
  38  *  - AND "size" doesn't have any high-bits set
  39  *  - AND "addr+size" doesn't have any high-bits set
  40  *  - OR we are in kernel mode.
  41  */
  42 #define __access_ok(addr,size,segment) \
  43         (((segment).seg & (addr | size | (addr+size))) == 0)
  44
  45 #define access_ok(type,addr,size)                               \
  46 ({                                                              \
  47         __chk_user_ptr(addr);                                   \
  48         __access_ok(((unsigned long)(addr)),(size),get_fs());   \
  49 })
  50
  51 /* this function will go away soon - use access_ok() instead */
  52 extern inline int __deprecated verify_area(int type, const void __user * addr, unsigned long size)
  53 {
  54         return access_ok(type,addr,size) ? 0 : -EFAULT;
  55 }
  56
  57 /*
  58  * These are the main single-value transfer routines.  They automatically
  59  * use the right size if we just have the right pointer type.
  60  *
  61  * As the alpha uses the same address space for kernel and user
  62  * data, we can just do these as direct assignments.  (Of course, the
  63  * exception handling means that it's no longer "just"...)
  64  *
  65  * Careful to not
  66  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  67  * (b) require any knowledge of processes at this stage
  68  */
  69 #define put_user(x,ptr) \
  70   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs())
  71 #define get_user(x,ptr) \
  72   __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
  73
  74 /*
  75  * The "__xxx" versions do not do address space checking, useful when
  76  * doing multiple accesses to the same area (the programmer has to do the
  77  * checks by hand with "access_ok()")
  78  */
  79 #define __put_user(x,ptr) \
  80   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  81 #define __get_user(x,ptr) \
  82   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  83
  84 /*
  85  * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
  86  * encode the bits we need for resolving the exception.  See the
  87  * more extensive comments with fixup_inline_exception below for
  88  * more information.
  89  */
  90
  91 extern void __get_user_unknown(void);
  92
  93 #define __get_user_nocheck(x,ptr,size)                          \
  94 ({                                                              \
  95         long __gu_err = 0;                                      \
  96         unsigned long __gu_val;                                 \
  97         __chk_user_ptr(ptr);                                    \
  98         switch (size) {                                         \
  99           case 1: __get_user_8(ptr); break;                     \
 100           case 2: __get_user_16(ptr); break;                    \
 101           case 4: __get_user_32(ptr); break;                    \
 102           case 8: __get_user_64(ptr); break;                    \
 103           default: __get_user_unknown(); break;                 \
 104         }                                                       \
 105         (x) = (__typeof__(*(ptr))) __gu_val;                    \
 106         __gu_err;                                               \
 107 })
 108
 109 #define __get_user_check(x,ptr,size,segment)                            \
 110 ({                                                                      \
 111         long __gu_err = -EFAULT;                                        \
 112         unsigned long __gu_val = 0;                                     \
 113         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 114         if (__access_ok((unsigned long)__gu_addr,size,segment)) {       \
 115                 __gu_err = 0;                                           \
 116                 switch (size) {                                         \
 117                   case 1: __get_user_8(__gu_addr); break;               \
 118                   case 2: __get_user_16(__gu_addr); break;              \
 119                   case 4: __get_user_32(__gu_addr); break;              \
 120                   case 8: __get_user_64(__gu_addr); break;              \
 121                   default: __get_user_unknown(); break;                 \
 122                 }                                                       \
 123         }                                                               \
 124         (x) = (__typeof__(*(ptr))) __gu_val;                            \
 125         __gu_err;                                                       \
 126 })
 127
 128 struct __large_struct { unsigned long buf[100]; };
 129 #define __m(x) (*(struct __large_struct __user *)(x))
 130
 131 #define __get_user_64(addr)                             \
 132         __asm__("1: ldq %0,%2\n"                        \
 133         "2:\n"                                          \
 134         ".section __ex_table,\"a\"\n"                   \
 135         "       .long 1b - .\n"                         \
 136         "       lda %0, 2b-1b(%1)\n"                    \
 137         ".previous"                                     \
 138                 : "=r"(__gu_val), "=r"(__gu_err)        \
 139                 : "m"(__m(addr)), "1"(__gu_err))
 140
 141 #define __get_user_32(addr)                             \
 142         __asm__("1: ldl %0,%2\n"                        \
 143         "2:\n"                                          \
 144         ".section __ex_table,\"a\"\n"                   \
 145         "       .long 1b - .\n"                         \
 146         "       lda %0, 2b-1b(%1)\n"                    \
 147         ".previous"                                     \
 148                 : "=r"(__gu_val), "=r"(__gu_err)        \
 149                 : "m"(__m(addr)), "1"(__gu_err))
 150
 151 #ifdef __alpha_bwx__
 152 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 153
 154 #define __get_user_16(addr)                             \
 155         __asm__("1: ldwu %0,%2\n"                       \
 156         "2:\n"                                          \
 157         ".section __ex_table,\"a\"\n"                   \
 158         "       .long 1b - .\n"                         \
 159         "       lda %0, 2b-1b(%1)\n"                    \
 160         ".previous"                                     \
 161                 : "=r"(__gu_val), "=r"(__gu_err)        \
 162                 : "m"(__m(addr)), "1"(__gu_err))
 163
 164 #define __get_user_8(addr)                              \
 165         __asm__("1: ldbu %0,%2\n"                       \
 166         "2:\n"                                          \
 167         ".section __ex_table,\"a\"\n"                   \
 168         "       .long 1b - .\n"                         \
 169         "       lda %0, 2b-1b(%1)\n"                    \
 170         ".previous"                                     \
 171                 : "=r"(__gu_val), "=r"(__gu_err)        \
 172                 : "m"(__m(addr)), "1"(__gu_err))
 173 #else
 174 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 175    load, so we have to do a general unaligned operation.  */
 176
 177 #define __get_user_16(addr)                                             \
 178 {                                                                       \
 179         long __gu_tmp;                                                  \
 180         __asm__("1: ldq_u %0,0(%3)\n"                                   \
 181         "2:     ldq_u %1,1(%3)\n"                                       \
 182         "       extwl %0,%3,%0\n"                                       \
 183         "       extwh %1,%3,%1\n"                                       \
 184         "       or %0,%1,%0\n"                                          \
 185         "3:\n"                                                          \
 186         ".section __ex_table,\"a\"\n"                                   \
 187         "       .long 1b - .\n"                                         \
 188         "       lda %0, 3b-1b(%2)\n"                                    \
 189         "       .long 2b - .\n"                                         \
 190         "       lda %0, 3b-2b(%2)\n"                                    \
 191         ".previous"                                                     \
 192                 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)      \
 193                 : "r"(addr), "2"(__gu_err));                            \
 194 }
 195
 196 #define __get_user_8(addr)                                              \
 197         __asm__("1: ldq_u %0,0(%2)\n"                                   \
 198         "       extbl %0,%2,%0\n"                                       \
 199         "2:\n"                                                          \
 200         ".section __ex_table,\"a\"\n"                                   \
 201         "       .long 1b - .\n"                                         \
 202         "       lda %0, 2b-1b(%1)\n"                                    \
 203         ".previous"                                                     \
 204                 : "=&r"(__gu_val), "=r"(__gu_err)                       \
 205                 : "r"(addr), "1"(__gu_err))
 206 #endif
 207
 208 extern void __put_user_unknown(void);
 209
 210 #define __put_user_nocheck(x,ptr,size)                          \
 211 ({                                                              \
 212         long __pu_err = 0;                                      \
 213         __chk_user_ptr(ptr);                                    \
 214         switch (size) {                                         \
 215           case 1: __put_user_8(x,ptr); break;                   \
 216           case 2: __put_user_16(x,ptr); break;                  \
 217           case 4: __put_user_32(x,ptr); break;                  \
 218           case 8: __put_user_64(x,ptr); break;                  \
 219           default: __put_user_unknown(); break;                 \
 220         }                                                       \
 221         __pu_err;                                               \
 222 })
 223
 224 #define __put_user_check(x,ptr,size,segment)                            \
 225 ({                                                                      \
 226         long __pu_err = -EFAULT;                                        \
 227         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 228         if (__access_ok((unsigned long)__pu_addr,size,segment)) {       \
 229                 __pu_err = 0;                                           \
 230                 switch (size) {                                         \
 231                   case 1: __put_user_8(x,__pu_addr); break;             \
 232                   case 2: __put_user_16(x,__pu_addr); break;            \
 233                   case 4: __put_user_32(x,__pu_addr); break;            \
 234                   case 8: __put_user_64(x,__pu_addr); break;            \
 235                   default: __put_user_unknown(); break;                 \
 236                 }                                                       \
 237         }                                                               \
 238         __pu_err;                                                       \
 239 })
 240
 241 /*
 242  * The "__put_user_xx()" macros tell gcc they read from memory
 243  * instead of writing: this is because they do not write to
 244  * any memory gcc knows about, so there are no aliasing issues
 245  */
 246 #define __put_user_64(x,addr)                                   \
 247 __asm__ __volatile__("1: stq %r2,%1\n"                          \
 248         "2:\n"                                                  \
 249         ".section __ex_table,\"a\"\n"                           \
 250         "       .long 1b - .\n"                                 \
 251         "       lda $31,2b-1b(%0)\n"                            \
 252         ".previous"                                             \
 253                 : "=r"(__pu_err)                                \
 254                 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
 255
 256 #define __put_user_32(x,addr)                                   \
 257 __asm__ __volatile__("1: stl %r2,%1\n"                          \
 258         "2:\n"                                                  \
 259         ".section __ex_table,\"a\"\n"                           \
 260         "       .long 1b - .\n"                                 \
 261         "       lda $31,2b-1b(%0)\n"                            \
 262         ".previous"                                             \
 263                 : "=r"(__pu_err)                                \
 264                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 265
 266 #ifdef __alpha_bwx__
 267 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 268
 269 #define __put_user_16(x,addr)                                   \
 270 __asm__ __volatile__("1: stw %r2,%1\n"                          \
 271         "2:\n"                                                  \
 272         ".section __ex_table,\"a\"\n"                           \
 273         "       .long 1b - .\n"                                 \
 274         "       lda $31,2b-1b(%0)\n"                            \
 275         ".previous"                                             \
 276                 : "=r"(__pu_err)                                \
 277                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 278
 279 #define __put_user_8(x,addr)                                    \
 280 __asm__ __volatile__("1: stb %r2,%1\n"                          \
 281         "2:\n"                                                  \
 282         ".section __ex_table,\"a\"\n"                           \
 283         "       .long 1b - .\n"                                 \
 284         "       lda $31,2b-1b(%0)\n"                            \
 285         ".previous"                                             \
 286                 : "=r"(__pu_err)                                \
 287                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 288 #else
 289 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 290    write, so we have to do a general unaligned operation.  */
 291
 292 #define __put_user_16(x,addr)                                   \
 293 {                                                               \
 294         long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;        \
 295         __asm__ __volatile__(                                   \
 296         "1:     ldq_u %2,1(%5)\n"                               \
 297         "2:     ldq_u %1,0(%5)\n"                               \
 298         "       inswh %6,%5,%4\n"                               \
 299         "       inswl %6,%5,%3\n"                               \
 300         "       mskwh %2,%5,%2\n"                               \
 301         "       mskwl %1,%5,%1\n"                               \
 302         "       or %2,%4,%2\n"                                  \
 303         "       or %1,%3,%1\n"                                  \
 304         "3:     stq_u %2,1(%5)\n"                               \
 305         "4:     stq_u %1,0(%5)\n"                               \
 306         "5:\n"                                                  \
 307         ".section __ex_table,\"a\"\n"                           \
 308         "       .long 1b - .\n"                                 \
 309         "       lda $31, 5b-1b(%0)\n"                           \
 310         "       .long 2b - .\n"                                 \
 311         "       lda $31, 5b-2b(%0)\n"                           \
 312         "       .long 3b - .\n"                                 \
 313         "       lda $31, 5b-3b(%0)\n"                           \
 314         "       .long 4b - .\n"                                 \
 315         "       lda $31, 5b-4b(%0)\n"                           \
 316         ".previous"                                             \
 317                 : "=r"(__pu_err), "=&r"(__pu_tmp1),             \
 318                   "=&r"(__pu_tmp2), "=&r"(__pu_tmp3),           \
 319                   "=&r"(__pu_tmp4)                              \
 320                 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
 321 }
 322
 323 #define __put_user_8(x,addr)                                    \
 324 {                                                               \
 325         long __pu_tmp1, __pu_tmp2;                              \
 326         __asm__ __volatile__(                                   \
 327         "1:     ldq_u %1,0(%4)\n"                               \
 328         "       insbl %3,%4,%2\n"                               \
 329         "       mskbl %1,%4,%1\n"                               \
 330         "       or %1,%2,%1\n"                                  \
 331         "2:     stq_u %1,0(%4)\n"                               \
 332         "3:\n"                                                  \
 333         ".section __ex_table,\"a\"\n"                           \
 334         "       .long 1b - .\n"                                 \
 335         "       lda $31, 3b-1b(%0)\n"                           \
 336         "       .long 2b - .\n"                                 \
 337         "       lda $31, 3b-2b(%0)\n"                           \
 338         ".previous"                                             \
 339                 : "=r"(__pu_err),                               \
 340                   "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)            \
 341                 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
 342 }
 343 #endif
 344
 345
 346 /*
 347  * Complex access routines
 348  */
 349
 350 /* This little bit of silliness is to get the GP loaded for a function
 351    that ordinarily wouldn't.  Otherwise we could have it done by the macro
 352    directly, which can be optimized the linker.  */
 353 #ifdef MODULE
 354 #define __module_address(sym)           "r"(sym),
 355 #define __module_call(ra, arg, sym)     "jsr $" #ra ",(%" #arg ")," #sym
 356 #else
 357 #define __module_address(sym)
 358 #define __module_call(ra, arg, sym)     "bsr $" #ra "," #sym " !samegp"
 359 #endif
 360
 361 extern void __copy_user(void);
 362
 363 extern inline long
 364 __copy_tofrom_user_nocheck(void *to, const void *from, long len)
 365 {
 366         register void * __cu_to __asm__("$6") = to;
 367         register const void * __cu_from __asm__("$7") = from;
 368         register long __cu_len __asm__("$0") = len;
 369
 370         __asm__ __volatile__(
 371                 __module_call(28, 3, __copy_user)
 372                 : "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
 373                 : __module_address(__copy_user)
 374                   "0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
 375                 : "$1","$2","$3","$4","$5","$28","memory");
 376
 377         return __cu_len;
 378 }
 379
 380 extern inline long
 381 __copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
 382 {
 383         if (__access_ok((unsigned long)validate, len, get_fs()))
 384                 len = __copy_tofrom_user_nocheck(to, from, len);
 385         return len;
 386 }
 387
 388 #define __copy_to_user(to,from,n)                                       \
 389 ({                                                                      \
 390         __chk_user_ptr(to);                                             \
 391         __copy_tofrom_user_nocheck((__force void *)(to),(from),(n));    \
 392 })
 393 #define __copy_from_user(to,from,n)                                     \
 394 ({                                                                      \
 395         __chk_user_ptr(from);                                           \
 396         __copy_tofrom_user_nocheck((to),(__force void *)(from),(n));    \
 397 })
 398
 399 #define __copy_to_user_inatomic __copy_to_user
 400 #define __copy_from_user_inatomic __copy_from_user
 401
 402
 403 extern inline long
 404 copy_to_user(void __user *to, const void *from, long n)
 405 {
 406         return __copy_tofrom_user((__force void *)to, from, n, to);
 407 }
 408
 409 extern inline long
 410 copy_from_user(void *to, const void __user *from, long n)
 411 {
 412         return __copy_tofrom_user(to, (__force void *)from, n, from);
 413 }
 414
 415 extern void __do_clear_user(void);
 416
 417 extern inline long
 418 __clear_user(void __user *to, long len)
 419 {
 420         register void __user * __cl_to __asm__("$6") = to;
 421         register long __cl_len __asm__("$0") = len;
 422         __asm__ __volatile__(
 423                 __module_call(28, 2, __do_clear_user)
 424                 : "=r"(__cl_len), "=r"(__cl_to)
 425                 : __module_address(__do_clear_user)
 426                   "0"(__cl_len), "1"(__cl_to)
 427                 : "$1","$2","$3","$4","$5","$28","memory");
 428         return __cl_len;
 429 }
 430
 431 extern inline long
 432 clear_user(void __user *to, long len)
 433 {
 434         if (__access_ok((unsigned long)to, len, get_fs()))
 435                 len = __clear_user(to, len);
 436         return len;
 437 }
 438
 439 #undef __module_address
 440 #undef __module_call
 441
 442 /* Returns: -EFAULT if exception before terminator, N if the entire
 443    buffer filled, else strlen.  */
 444
 445 extern long __strncpy_from_user(char *__to, const char __user *__from, long __to_len);
 446
 447 extern inline long
 448 strncpy_from_user(char *to, const char __user *from, long n)
 449 {
 450         long ret = -EFAULT;
 451         if (__access_ok((unsigned long)from, 0, get_fs()))
 452                 ret = __strncpy_from_user(to, from, n);
 453         return ret;
 454 }
 455
 456 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 457 extern long __strlen_user(const char __user *);
 458
 459 extern inline long strlen_user(const char __user *str)
 460 {
 461         return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
 462 }
 463
 464 /* Returns: 0 if exception before NUL or reaching the supplied limit (N),
 465  * a value greater than N if the limit would be exceeded, else strlen.  */
 466 extern long __strnlen_user(const char __user *, long);
 467
 468 extern inline long strnlen_user(const char __user *str, long n)
 469 {
 470         return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
 471 }
 472
 473 /*
 474  * About the exception table:
 475  *
 476  * - insn is a 32-bit pc-relative offset from the faulting insn.
 477  * - nextinsn is a 16-bit offset off of the faulting instruction
 478  *   (not off of the *next* instruction as branches are).
 479  * - errreg is the register in which to place -EFAULT.
 480  * - valreg is the final target register for the load sequence
 481  *   and will be zeroed.
 482  *
 483  * Either errreg or valreg may be $31, in which case nothing happens.
 484  *
 485  * The exception fixup information "just so happens" to be arranged
 486  * as in a MEM format instruction.  This lets us emit our three
 487  * values like so:
 488  *
 489  *      lda valreg, nextinsn(errreg)
 490  *
 491  */
 492
 493 struct exception_table_entry
 494 {
 495         signed int insn;
 496         union exception_fixup {
 497                 unsigned unit;
 498                 struct {
 499                         signed int nextinsn : 16;
 500                         unsigned int errreg : 5;
 501                         unsigned int valreg : 5;
 502                 } bits;
 503         } fixup;
 504 };
 505
 506 /* Returns the new pc */
 507 #define fixup_exception(map_reg, fixup, pc)                     \
 508 ({                                                              \
 509         if ((fixup)->fixup.bits.valreg != 31)                   \
 510                 map_reg((fixup)->fixup.bits.valreg) = 0;        \
 511         if ((fixup)->fixup.bits.errreg != 31)                   \
 512                 map_reg((fixup)->fixup.bits.errreg) = -EFAULT;  \
 513         (pc) + (fixup)->fixup.bits.nextinsn;                    \
 514 })
 515
 516
 517 #endif /* __ALPHA_UACCESS_H */