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 /*
  34  * Is a address valid? This does a straightforward calculation rather
  35  * than tests.
  36  *
  37  * Address valid if:
  38  *  - "addr" doesn't have any high-bits set
  39  *  - AND "size" doesn't have any high-bits set
  40  *  - AND "addr+size" doesn't have any high-bits set
  41  *  - OR we are in kernel mode.
  42  */
  43 #define __access_ok(addr,size,segment) \
  44         (((segment).seg & (addr | size | (addr+size))) == 0)
  45
  46 #define access_ok(type,addr,size) \
  47         __access_ok(((unsigned long)(addr)),(size),get_fs())
  48
  49 extern inline int verify_area(int type, const void * addr, unsigned long size)
  50 {
  51         return access_ok(type,addr,size) ? 0 : -EFAULT;
  52 }
  53
  54 /*
  55  * These are the main single-value transfer routines.  They automatically
  56  * use the right size if we just have the right pointer type.
  57  *
  58  * As the alpha uses the same address space for kernel and user
  59  * data, we can just do these as direct assignments.  (Of course, the
  60  * exception handling means that it's no longer "just"...)
  61  *
  62  * Careful to not
  63  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  64  * (b) require any knowledge of processes at this stage
  65  */
  66 #define put_user(x,ptr) \
  67   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs())
  68 #define get_user(x,ptr) \
  69   __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
  70
  71 /*
  72  * The "__xxx" versions do not do address space checking, useful when
  73  * doing multiple accesses to the same area (the programmer has to do the
  74  * checks by hand with "access_ok()")
  75  */
  76 #define __put_user(x,ptr) \
  77   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  78 #define __get_user(x,ptr) \
  79   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  80
  81 /*
  82  * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
  83  * encode the bits we need for resolving the exception.  See the
  84  * more extensive comments with fixup_inline_exception below for
  85  * more information.
  86  */
  87
  88 extern void __get_user_unknown(void);
  89
  90 #define __get_user_nocheck(x,ptr,size)                          \
  91 ({                                                              \
  92         long __gu_err = 0, __gu_val;                            \
  93         switch (size) {                                         \
  94           case 1: __get_user_8(ptr); break;                     \
  95           case 2: __get_user_16(ptr); break;                    \
  96           case 4: __get_user_32(ptr); break;                    \
  97           case 8: __get_user_64(ptr); break;                    \
  98           default: __get_user_unknown(); break;                 \
  99         }                                                       \
 100         (x) = (__typeof__(*(ptr))) __gu_val;                    \
 101         __gu_err;                                               \
 102 })
 103
 104 #define __get_user_check(x,ptr,size,segment)                    \
 105 ({                                                              \
 106         long __gu_err = -EFAULT, __gu_val = 0;                  \
 107         const __typeof__(*(ptr)) *__gu_addr = (ptr);            \
 108         if (__access_ok((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 *)(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         switch (size) {                                         \
 208           case 1: __put_user_8(x,ptr); break;                   \
 209           case 2: __put_user_16(x,ptr); break;                  \
 210           case 4: __put_user_32(x,ptr); break;                  \
 211           case 8: __put_user_64(x,ptr); break;                  \
 212           default: __put_user_unknown(); break;                 \
 213         }                                                       \
 214         __pu_err;                                               \
 215 })
 216
 217 #define __put_user_check(x,ptr,size,segment)                    \
 218 ({                                                              \
 219         long __pu_err = -EFAULT;                                \
 220         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 221         if (__access_ok((long)__pu_addr,size,segment)) {        \
 222                 __pu_err = 0;                                   \
 223                 switch (size) {                                 \
 224                   case 1: __put_user_8(x,__pu_addr); break;     \
 225                   case 2: __put_user_16(x,__pu_addr); break;    \
 226                   case 4: __put_user_32(x,__pu_addr); break;    \
 227                   case 8: __put_user_64(x,__pu_addr); break;    \
 228                   default: __put_user_unknown(); break;         \
 229                 }                                               \
 230         }                                                       \
 231         __pu_err;                                               \
 232 })
 233
 234 /*
 235  * The "__put_user_xx()" macros tell gcc they read from memory
 236  * instead of writing: this is because they do not write to
 237  * any memory gcc knows about, so there are no aliasing issues
 238  */
 239 #define __put_user_64(x,addr)                                   \
 240 __asm__ __volatile__("1: stq %r2,%1\n"                          \
 241         "2:\n"                                                  \
 242         ".section __ex_table,\"a\"\n"                           \
 243         "       .long 1b - .\n"                                 \
 244         "       lda $31,2b-1b(%0)\n"                            \
 245         ".previous"                                             \
 246                 : "=r"(__pu_err)                                \
 247                 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
 248
 249 #define __put_user_32(x,addr)                                   \
 250 __asm__ __volatile__("1: stl %r2,%1\n"                          \
 251         "2:\n"                                                  \
 252         ".section __ex_table,\"a\"\n"                           \
 253         "       .long 1b - .\n"                                 \
 254         "       lda $31,2b-1b(%0)\n"                            \
 255         ".previous"                                             \
 256                 : "=r"(__pu_err)                                \
 257                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 258
 259 #ifdef __alpha_bwx__
 260 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 261
 262 #define __put_user_16(x,addr)                                   \
 263 __asm__ __volatile__("1: stw %r2,%1\n"                          \
 264         "2:\n"                                                  \
 265         ".section __ex_table,\"a\"\n"                           \
 266         "       .long 1b - .\n"                                 \
 267         "       lda $31,2b-1b(%0)\n"                            \
 268         ".previous"                                             \
 269                 : "=r"(__pu_err)                                \
 270                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 271
 272 #define __put_user_8(x,addr)                                    \
 273 __asm__ __volatile__("1: stb %r2,%1\n"                          \
 274         "2:\n"                                                  \
 275         ".section __ex_table,\"a\"\n"                           \
 276         "       .long 1b - .\n"                                 \
 277         "       lda $31,2b-1b(%0)\n"                            \
 278         ".previous"                                             \
 279                 : "=r"(__pu_err)                                \
 280                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 281 #else
 282 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 283    write, so we have to do a general unaligned operation.  */
 284
 285 #define __put_user_16(x,addr)                                   \
 286 {                                                               \
 287         long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;        \
 288         __asm__ __volatile__(                                   \
 289         "1:     ldq_u %2,1(%5)\n"                               \
 290         "2:     ldq_u %1,0(%5)\n"                               \
 291         "       inswh %6,%5,%4\n"                               \
 292         "       inswl %6,%5,%3\n"                               \
 293         "       mskwh %2,%5,%2\n"                               \
 294         "       mskwl %1,%5,%1\n"                               \
 295         "       or %2,%4,%2\n"                                  \
 296         "       or %1,%3,%1\n"                                  \
 297         "3:     stq_u %2,1(%5)\n"                               \
 298         "4:     stq_u %1,0(%5)\n"                               \
 299         "5:\n"                                                  \
 300         ".section __ex_table,\"a\"\n"                           \
 301         "       .long 1b - .\n"                                 \
 302         "       lda $31, 5b-1b(%0)\n"                           \
 303         "       .long 2b - .\n"                                 \
 304         "       lda $31, 5b-2b(%0)\n"                           \
 305         "       .long 3b - .\n"                                 \
 306         "       lda $31, 5b-3b(%0)\n"                           \
 307         "       .long 4b - .\n"                                 \
 308         "       lda $31, 5b-4b(%0)\n"                           \
 309         ".previous"                                             \
 310                 : "=r"(__pu_err), "=&r"(__pu_tmp1),             \
 311                   "=&r"(__pu_tmp2), "=&r"(__pu_tmp3),           \
 312                   "=&r"(__pu_tmp4)                              \
 313                 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
 314 }
 315
 316 #define __put_user_8(x,addr)                                    \
 317 {                                                               \
 318         long __pu_tmp1, __pu_tmp2;                              \
 319         __asm__ __volatile__(                                   \
 320         "1:     ldq_u %1,0(%4)\n"                               \
 321         "       insbl %3,%4,%2\n"                               \
 322         "       mskbl %1,%4,%1\n"                               \
 323         "       or %1,%2,%1\n"                                  \
 324         "2:     stq_u %1,0(%4)\n"                               \
 325         "3:\n"                                                  \
 326         ".section __ex_table,\"a\"\n"                           \
 327         "       .long 1b - .\n"                                 \
 328         "       lda $31, 3b-1b(%0)\n"                           \
 329         "       .long 2b - .\n"                                 \
 330         "       lda $31, 3b-2b(%0)\n"                           \
 331         ".previous"                                             \
 332                 : "=r"(__pu_err),                               \
 333                   "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)            \
 334                 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
 335 }
 336 #endif
 337
 338
 339 /*
 340  * Complex access routines
 341  */
 342
 343 /* This little bit of silliness is to get the GP loaded for a function
 344    that ordinarily wouldn't.  Otherwise we could have it done by the macro
 345    directly, which can be optimized the linker.  */
 346 #ifdef MODULE
 347 #define __module_address(sym)           "r"(sym),
 348 #define __module_call(ra, arg, sym)     "jsr $" #ra ",(%" #arg ")," #sym
 349 #else
 350 #define __module_address(sym)
 351 #define __module_call(ra, arg, sym)     "bsr $" #ra "," #sym " !samegp"
 352 #endif
 353
 354 extern void __copy_user(void);
 355
 356 extern inline long
 357 __copy_tofrom_user_nocheck(void *to, const void *from, long len)
 358 {
 359         register void * __cu_to __asm__("$6") = to;
 360         register const void * __cu_from __asm__("$7") = from;
 361         register long __cu_len __asm__("$0") = len;
 362
 363         __asm__ __volatile__(
 364                 __module_call(28, 3, __copy_user)
 365                 : "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
 366                 : __module_address(__copy_user)
 367                   "0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
 368                 : "$1","$2","$3","$4","$5","$28","memory");
 369
 370         return __cu_len;
 371 }
 372
 373 extern inline long
 374 __copy_tofrom_user(void *to, const void *from, long len, const void *validate)
 375 {
 376         if (__access_ok((long)validate, len, get_fs()))
 377                 len = __copy_tofrom_user_nocheck(to, from, len);
 378         return len;
 379 }
 380
 381 #define __copy_to_user(to,from,n)   __copy_tofrom_user_nocheck((to),(from),(n))
 382 #define __copy_from_user(to,from,n) __copy_tofrom_user_nocheck((to),(from),(n))
 383
 384 extern inline long
 385 copy_to_user(void *to, const void *from, long n)
 386 {
 387         return __copy_tofrom_user(to, from, n, to);
 388 }
 389
 390 extern inline long
 391 copy_from_user(void *to, const void *from, long n)
 392 {
 393         return __copy_tofrom_user(to, from, n, from);
 394 }
 395
 396 extern void __do_clear_user(void);
 397
 398 extern inline long
 399 __clear_user(void *to, long len)
 400 {
 401         register void * __cl_to __asm__("$6") = to;
 402         register long __cl_len __asm__("$0") = len;
 403         __asm__ __volatile__(
 404                 __module_call(28, 2, __do_clear_user)
 405                 : "=r"(__cl_len), "=r"(__cl_to)
 406                 : __module_address(__do_clear_user)
 407                   "0"(__cl_len), "1"(__cl_to)
 408                 : "$1","$2","$3","$4","$5","$28","memory");
 409         return __cl_len;
 410 }
 411
 412 extern inline long
 413 clear_user(void *to, long len)
 414 {
 415         if (__access_ok((long)to, len, get_fs()))
 416                 len = __clear_user(to, len);
 417         return len;
 418 }
 419
 420 #undef __module_address
 421 #undef __module_call
 422
 423 /* Returns: -EFAULT if exception before terminator, N if the entire
 424    buffer filled, else strlen.  */
 425
 426 extern long __strncpy_from_user(char *__to, const char *__from, long __to_len);
 427
 428 extern inline long
 429 strncpy_from_user(char *to, const char *from, long n)
 430 {
 431         long ret = -EFAULT;
 432         if (__access_ok((long)from, 0, get_fs()))
 433                 ret = __strncpy_from_user(to, from, n);
 434         return ret;
 435 }
 436
 437 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 438 extern long __strlen_user(const char *);
 439
 440 extern inline long strlen_user(const char *str)
 441 {
 442         return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
 443 }
 444
 445 /* Returns: 0 if exception before NUL or reaching the supplied limit (N),
 446  * a value greater than N if the limit would be exceeded, else strlen.  */
 447 extern long __strnlen_user(const char *, long);
 448
 449 extern inline long strnlen_user(const char *str, long n)
 450 {
 451         return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
 452 }
 453
 454 /*
 455  * About the exception table:
 456  *
 457  * - insn is a 32-bit pc-relative offset from the faulting insn.
 458  * - nextinsn is a 16-bit offset off of the faulting instruction
 459  *   (not off of the *next* instruction as branches are).
 460  * - errreg is the register in which to place -EFAULT.
 461  * - valreg is the final target register for the load sequence
 462  *   and will be zeroed.
 463  *
 464  * Either errreg or valreg may be $31, in which case nothing happens.
 465  *
 466  * The exception fixup information "just so happens" to be arranged
 467  * as in a MEM format instruction.  This lets us emit our three
 468  * values like so:
 469  *
 470  *      lda valreg, nextinsn(errreg)
 471  *
 472  */
 473
 474 struct exception_table_entry
 475 {
 476         signed int insn;
 477         union exception_fixup {
 478                 unsigned unit;
 479                 struct {
 480                         signed int nextinsn : 16;
 481                         unsigned int errreg : 5;
 482                         unsigned int valreg : 5;
 483                 } bits;
 484         } fixup;
 485 };
 486
 487 /* Returns the new pc */
 488 #define fixup_exception(map_reg, fixup, pc)                     \
 489 ({                                                              \
 490         if ((fixup)->fixup.bits.valreg != 31)                   \
 491                 map_reg((fixup)->fixup.bits.valreg) = 0;        \
 492         if ((fixup)->fixup.bits.errreg != 31)                   \
 493                 map_reg((fixup)->fixup.bits.errreg) = -EFAULT;  \
 494         (pc) + (fixup)->fixup.bits.nextinsn;                    \
 495 })
 496
 497
 498 #endif /* __ALPHA_UACCESS_H */