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