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