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 #ifdef __CHECKER__
  33 #define CHECK_UPTR(ptr) do {                            \
  34         __typeof__(*(ptr)) *__dummy_check_uptr =        \
  35                 (void __user *)&__dummy_check_uptr;     \
  36 } while(0)
  37 #else
  38 #define CHECK_UPTR(ptr)
  39 #endif
  40
  41 /*
  42  * Is a address valid? This does a straightforward calculation rather
  43  * than tests.
  44  *
  45  * Address valid if:
  46  *  - "addr" doesn't have any high-bits set
  47  *  - AND "size" doesn't have any high-bits set
  48  *  - AND "addr+size" doesn't have any high-bits set
  49  *  - OR we are in kernel mode.
  50  */
  51 #define __access_ok(addr,size,segment) \
  52         (((segment).seg & (addr | size | (addr+size))) == 0)
  53
  54 #define access_ok(type,addr,size)                               \
  55 ({                                                              \
  56         CHECK_UPTR(addr);                                       \
  57         __access_ok(((unsigned long)(addr)),(size),get_fs());   \
  58 })
  59
  60 extern inline int verify_area(int type, const void __user * addr, unsigned long size)
  61 {
  62         return access_ok(type,addr,size) ? 0 : -EFAULT;
  63 }
  64
  65 /*
  66  * These are the main single-value transfer routines.  They automatically
  67  * use the right size if we just have the right pointer type.
  68  *
  69  * As the alpha uses the same address space for kernel and user
  70  * data, we can just do these as direct assignments.  (Of course, the
  71  * exception handling means that it's no longer "just"...)
  72  *
  73  * Careful to not
  74  * (a) re-use the arguments for side effects (sizeof/typeof is ok)
  75  * (b) require any knowledge of processes at this stage
  76  */
  77 #define put_user(x,ptr) \
  78   __put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)),get_fs())
  79 #define get_user(x,ptr) \
  80   __get_user_check((x),(ptr),sizeof(*(ptr)),get_fs())
  81
  82 /*
  83  * The "__xxx" versions do not do address space checking, useful when
  84  * doing multiple accesses to the same area (the programmer has to do the
  85  * checks by hand with "access_ok()")
  86  */
  87 #define __put_user(x,ptr) \
  88   __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
  89 #define __get_user(x,ptr) \
  90   __get_user_nocheck((x),(ptr),sizeof(*(ptr)))
  91
  92 /*
  93  * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
  94  * encode the bits we need for resolving the exception.  See the
  95  * more extensive comments with fixup_inline_exception below for
  96  * more information.
  97  */
  98
  99 extern void __get_user_unknown(void);
 100
 101 #define __get_user_nocheck(x,ptr,size)                          \
 102 ({                                                              \
 103         long __gu_err = 0, __gu_val;                            \
 104         CHECK_UPTR(ptr);                                        \
 105         switch (size) {                                         \
 106           case 1: __get_user_8(ptr); break;                     \
 107           case 2: __get_user_16(ptr); break;                    \
 108           case 4: __get_user_32(ptr); break;                    \
 109           case 8: __get_user_64(ptr); break;                    \
 110           default: __get_user_unknown(); break;                 \
 111         }                                                       \
 112         (x) = (__typeof__(*(ptr))) __gu_val;                    \
 113         __gu_err;                                               \
 114 })
 115
 116 #define __get_user_check(x,ptr,size,segment)                    \
 117 ({                                                              \
 118         long __gu_err = -EFAULT, __gu_val = 0;                  \
 119         const __typeof__(*(ptr)) *__gu_addr = (ptr);            \
 120         CHECK_UPTR(ptr);                                        \
 121         if (__access_ok((long)__gu_addr,size,segment)) {        \
 122                 __gu_err = 0;                                   \
 123                 switch (size) {                                 \
 124                   case 1: __get_user_8(__gu_addr); break;       \
 125                   case 2: __get_user_16(__gu_addr); break;      \
 126                   case 4: __get_user_32(__gu_addr); break;      \
 127                   case 8: __get_user_64(__gu_addr); break;      \
 128                   default: __get_user_unknown(); break;         \
 129                 }                                               \
 130         }                                                       \
 131         (x) = (__typeof__(*(ptr))) __gu_val;                    \
 132         __gu_err;                                               \
 133 })
 134
 135 struct __large_struct { unsigned long buf[100]; };
 136 #define __m(x) (*(struct __large_struct *)(x))
 137
 138 #define __get_user_64(addr)                             \
 139         __asm__("1: ldq %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 #define __get_user_32(addr)                             \
 149         __asm__("1: ldl %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 #ifdef __alpha_bwx__
 159 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 160
 161 #define __get_user_16(addr)                             \
 162         __asm__("1: ldwu %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
 171 #define __get_user_8(addr)                              \
 172         __asm__("1: ldbu %0,%2\n"                       \
 173         "2:\n"                                          \
 174         ".section __ex_table,\"a\"\n"                   \
 175         "       .long 1b - .\n"                         \
 176         "       lda %0, 2b-1b(%1)\n"                    \
 177         ".previous"                                     \
 178                 : "=r"(__gu_val), "=r"(__gu_err)        \
 179                 : "m"(__m(addr)), "1"(__gu_err))
 180 #else
 181 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 182    load, so we have to do a general unaligned operation.  */
 183
 184 #define __get_user_16(addr)                                             \
 185 {                                                                       \
 186         long __gu_tmp;                                                  \
 187         __asm__("1: ldq_u %0,0(%3)\n"                                   \
 188         "2:     ldq_u %1,1(%3)\n"                                       \
 189         "       extwl %0,%3,%0\n"                                       \
 190         "       extwh %1,%3,%1\n"                                       \
 191         "       or %0,%1,%0\n"                                          \
 192         "3:\n"                                                          \
 193         ".section __ex_table,\"a\"\n"                                   \
 194         "       .long 1b - .\n"                                         \
 195         "       lda %0, 3b-1b(%2)\n"                                    \
 196         "       .long 2b - .\n"                                         \
 197         "       lda %0, 3b-2b(%2)\n"                                    \
 198         ".previous"                                                     \
 199                 : "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)      \
 200                 : "r"(addr), "2"(__gu_err));                            \
 201 }
 202
 203 #define __get_user_8(addr)                                              \
 204         __asm__("1: ldq_u %0,0(%2)\n"                                   \
 205         "       extbl %0,%2,%0\n"                                       \
 206         "2:\n"                                                          \
 207         ".section __ex_table,\"a\"\n"                                   \
 208         "       .long 1b - .\n"                                         \
 209         "       lda %0, 2b-1b(%1)\n"                                    \
 210         ".previous"                                                     \
 211                 : "=&r"(__gu_val), "=r"(__gu_err)                       \
 212                 : "r"(addr), "1"(__gu_err))
 213 #endif
 214
 215 extern void __put_user_unknown(void);
 216
 217 #define __put_user_nocheck(x,ptr,size)                          \
 218 ({                                                              \
 219         long __pu_err = 0;                                      \
 220         CHECK_UPTR(ptr);                                        \
 221         switch (size) {                                         \
 222           case 1: __put_user_8(x,ptr); break;                   \
 223           case 2: __put_user_16(x,ptr); break;                  \
 224           case 4: __put_user_32(x,ptr); break;                  \
 225           case 8: __put_user_64(x,ptr); break;                  \
 226           default: __put_user_unknown(); break;                 \
 227         }                                                       \
 228         __pu_err;                                               \
 229 })
 230
 231 #define __put_user_check(x,ptr,size,segment)                    \
 232 ({                                                              \
 233         long __pu_err = -EFAULT;                                \
 234         __typeof__(*(ptr)) *__pu_addr = (ptr);                  \
 235         CHECK_UPTR(ptr);                                        \
 236         if (__access_ok((long)__pu_addr,size,segment)) {        \
 237                 __pu_err = 0;                                   \
 238                 switch (size) {                                 \
 239                   case 1: __put_user_8(x,__pu_addr); break;     \
 240                   case 2: __put_user_16(x,__pu_addr); break;    \
 241                   case 4: __put_user_32(x,__pu_addr); break;    \
 242                   case 8: __put_user_64(x,__pu_addr); break;    \
 243                   default: __put_user_unknown(); break;         \
 244                 }                                               \
 245         }                                                       \
 246         __pu_err;                                               \
 247 })
 248
 249 /*
 250  * The "__put_user_xx()" macros tell gcc they read from memory
 251  * instead of writing: this is because they do not write to
 252  * any memory gcc knows about, so there are no aliasing issues
 253  */
 254 #define __put_user_64(x,addr)                                   \
 255 __asm__ __volatile__("1: stq %r2,%1\n"                          \
 256         "2:\n"                                                  \
 257         ".section __ex_table,\"a\"\n"                           \
 258         "       .long 1b - .\n"                                 \
 259         "       lda $31,2b-1b(%0)\n"                            \
 260         ".previous"                                             \
 261                 : "=r"(__pu_err)                                \
 262                 : "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
 263
 264 #define __put_user_32(x,addr)                                   \
 265 __asm__ __volatile__("1: stl %r2,%1\n"                          \
 266         "2:\n"                                                  \
 267         ".section __ex_table,\"a\"\n"                           \
 268         "       .long 1b - .\n"                                 \
 269         "       lda $31,2b-1b(%0)\n"                            \
 270         ".previous"                                             \
 271                 : "=r"(__pu_err)                                \
 272                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 273
 274 #ifdef __alpha_bwx__
 275 /* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
 276
 277 #define __put_user_16(x,addr)                                   \
 278 __asm__ __volatile__("1: stw %r2,%1\n"                          \
 279         "2:\n"                                                  \
 280         ".section __ex_table,\"a\"\n"                           \
 281         "       .long 1b - .\n"                                 \
 282         "       lda $31,2b-1b(%0)\n"                            \
 283         ".previous"                                             \
 284                 : "=r"(__pu_err)                                \
 285                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 286
 287 #define __put_user_8(x,addr)                                    \
 288 __asm__ __volatile__("1: stb %r2,%1\n"                          \
 289         "2:\n"                                                  \
 290         ".section __ex_table,\"a\"\n"                           \
 291         "       .long 1b - .\n"                                 \
 292         "       lda $31,2b-1b(%0)\n"                            \
 293         ".previous"                                             \
 294                 : "=r"(__pu_err)                                \
 295                 : "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
 296 #else
 297 /* Unfortunately, we can't get an unaligned access trap for the sub-word
 298    write, so we have to do a general unaligned operation.  */
 299
 300 #define __put_user_16(x,addr)                                   \
 301 {                                                               \
 302         long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;        \
 303         __asm__ __volatile__(                                   \
 304         "1:     ldq_u %2,1(%5)\n"                               \
 305         "2:     ldq_u %1,0(%5)\n"                               \
 306         "       inswh %6,%5,%4\n"                               \
 307         "       inswl %6,%5,%3\n"                               \
 308         "       mskwh %2,%5,%2\n"                               \
 309         "       mskwl %1,%5,%1\n"                               \
 310         "       or %2,%4,%2\n"                                  \
 311         "       or %1,%3,%1\n"                                  \
 312         "3:     stq_u %2,1(%5)\n"                               \
 313         "4:     stq_u %1,0(%5)\n"                               \
 314         "5:\n"                                                  \
 315         ".section __ex_table,\"a\"\n"                           \
 316         "       .long 1b - .\n"                                 \
 317         "       lda $31, 5b-1b(%0)\n"                           \
 318         "       .long 2b - .\n"                                 \
 319         "       lda $31, 5b-2b(%0)\n"                           \
 320         "       .long 3b - .\n"                                 \
 321         "       lda $31, 5b-3b(%0)\n"                           \
 322         "       .long 4b - .\n"                                 \
 323         "       lda $31, 5b-4b(%0)\n"                           \
 324         ".previous"                                             \
 325                 : "=r"(__pu_err), "=&r"(__pu_tmp1),             \
 326                   "=&r"(__pu_tmp2), "=&r"(__pu_tmp3),           \
 327                   "=&r"(__pu_tmp4)                              \
 328                 : "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
 329 }
 330
 331 #define __put_user_8(x,addr)                                    \
 332 {                                                               \
 333         long __pu_tmp1, __pu_tmp2;                              \
 334         __asm__ __volatile__(                                   \
 335         "1:     ldq_u %1,0(%4)\n"                               \
 336         "       insbl %3,%4,%2\n"                               \
 337         "       mskbl %1,%4,%1\n"                               \
 338         "       or %1,%2,%1\n"                                  \
 339         "2:     stq_u %1,0(%4)\n"                               \
 340         "3:\n"                                                  \
 341         ".section __ex_table,\"a\"\n"                           \
 342         "       .long 1b - .\n"                                 \
 343         "       lda $31, 3b-1b(%0)\n"                           \
 344         "       .long 2b - .\n"                                 \
 345         "       lda $31, 3b-2b(%0)\n"                           \
 346         ".previous"                                             \
 347                 : "=r"(__pu_err),                               \
 348                   "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)            \
 349                 : "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
 350 }
 351 #endif
 352
 353
 354 /*
 355  * Complex access routines
 356  */
 357
 358 /* This little bit of silliness is to get the GP loaded for a function
 359    that ordinarily wouldn't.  Otherwise we could have it done by the macro
 360    directly, which can be optimized the linker.  */
 361 #ifdef MODULE
 362 #define __module_address(sym)           "r"(sym),
 363 #define __module_call(ra, arg, sym)     "jsr $" #ra ",(%" #arg ")," #sym
 364 #else
 365 #define __module_address(sym)
 366 #define __module_call(ra, arg, sym)     "bsr $" #ra "," #sym " !samegp"
 367 #endif
 368
 369 extern void __copy_user(void);
 370
 371 extern inline long
 372 __copy_tofrom_user_nocheck(void *to, const void *from, long len)
 373 {
 374         register void * __cu_to __asm__("$6") = to;
 375         register const void * __cu_from __asm__("$7") = from;
 376         register long __cu_len __asm__("$0") = len;
 377
 378         __asm__ __volatile__(
 379                 __module_call(28, 3, __copy_user)
 380                 : "=r" (__cu_len), "=r" (__cu_from), "=r" (__cu_to)
 381                 : __module_address(__copy_user)
 382                   "0" (__cu_len), "1" (__cu_from), "2" (__cu_to)
 383                 : "$1","$2","$3","$4","$5","$28","memory");
 384
 385         return __cu_len;
 386 }
 387
 388 extern inline long
 389 __copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
 390 {
 391         if (__access_ok((long)validate, len, get_fs()))
 392                 len = __copy_tofrom_user_nocheck(to, from, len);
 393         return len;
 394 }
 395
 396 #define __copy_to_user(to,from,n)                               \
 397 ({                                                              \
 398         CHECK_UPTR(to);                                         \
 399         __copy_tofrom_user_nocheck((void *)(to),(from),(n));    \
 400 })
 401 #define __copy_from_user(to,from,n)                             \
 402 ({                                                              \
 403         CHECK_UPTR(from);                                       \
 404         __copy_tofrom_user_nocheck((to),(void *)(from),(n));    \
 405 })
 406
 407 extern inline long
 408 copy_to_user(void __user *to, const void *from, long n)
 409 {
 410         return __copy_tofrom_user((void *)to, from, n, to);
 411 }
 412
 413 extern inline long
 414 copy_from_user(void *to, const void __user *from, long n)
 415 {
 416         return __copy_tofrom_user(to, (void *)from, n, from);
 417 }
 418
 419 extern void __do_clear_user(void);
 420
 421 extern inline long
 422 __clear_user(void __user *to, long len)
 423 {
 424         register void __user * __cl_to __asm__("$6") = to;
 425         register long __cl_len __asm__("$0") = len;
 426         __asm__ __volatile__(
 427                 __module_call(28, 2, __do_clear_user)
 428                 : "=r"(__cl_len), "=r"(__cl_to)
 429                 : __module_address(__do_clear_user)
 430                   "0"(__cl_len), "1"(__cl_to)
 431                 : "$1","$2","$3","$4","$5","$28","memory");
 432         return __cl_len;
 433 }
 434
 435 extern inline long
 436 clear_user(void __user *to, long len)
 437 {
 438         if (__access_ok((long)to, len, get_fs()))
 439                 len = __clear_user(to, len);
 440         return len;
 441 }
 442
 443 #undef __module_address
 444 #undef __module_call
 445
 446 /* Returns: -EFAULT if exception before terminator, N if the entire
 447    buffer filled, else strlen.  */
 448
 449 extern long __strncpy_from_user(char *__to, const char __user *__from, long __to_len);
 450
 451 extern inline long
 452 strncpy_from_user(char *to, const char __user *from, long n)
 453 {
 454         long ret = -EFAULT;
 455         if (__access_ok((long)from, 0, get_fs()))
 456                 ret = __strncpy_from_user(to, from, n);
 457         return ret;
 458 }
 459
 460 /* Returns: 0 if bad, string length+1 (memory size) of string if ok */
 461 extern long __strlen_user(const char __user *);
 462
 463 extern inline long strlen_user(const char __user *str)
 464 {
 465         return access_ok(VERIFY_READ,str,0) ? __strlen_user(str) : 0;
 466 }
 467
 468 /* Returns: 0 if exception before NUL or reaching the supplied limit (N),
 469  * a value greater than N if the limit would be exceeded, else strlen.  */
 470 extern long __strnlen_user(const char __user *, long);
 471
 472 extern inline long strnlen_user(const char __user *str, long n)
 473 {
 474         return access_ok(VERIFY_READ,str,0) ? __strnlen_user(str, n) : 0;
 475 }
 476
 477 /*
 478  * About the exception table:
 479  *
 480  * - insn is a 32-bit pc-relative offset from the faulting insn.
 481  * - nextinsn is a 16-bit offset off of the faulting instruction
 482  *   (not off of the *next* instruction as branches are).
 483  * - errreg is the register in which to place -EFAULT.
 484  * - valreg is the final target register for the load sequence
 485  *   and will be zeroed.
 486  *
 487  * Either errreg or valreg may be $31, in which case nothing happens.
 488  *
 489  * The exception fixup information "just so happens" to be arranged
 490  * as in a MEM format instruction.  This lets us emit our three
 491  * values like so:
 492  *
 493  *      lda valreg, nextinsn(errreg)
 494  *
 495  */
 496
 497 struct exception_table_entry
 498 {
 499         signed int insn;
 500         union exception_fixup {
 501                 unsigned unit;
 502                 struct {
 503                         signed int nextinsn : 16;
 504                         unsigned int errreg : 5;
 505                         unsigned int valreg : 5;
 506                 } bits;
 507         } fixup;
 508 };
 509
 510 /* Returns the new pc */
 511 #define fixup_exception(map_reg, fixup, pc)                     \
 512 ({                                                              \
 513         if ((fixup)->fixup.bits.valreg != 31)                   \
 514                 map_reg((fixup)->fixup.bits.valreg) = 0;        \
 515         if ((fixup)->fixup.bits.errreg != 31)                   \
 516                 map_reg((fixup)->fixup.bits.errreg) = -EFAULT;  \
 517         (pc) + (fixup)->fixup.bits.nextinsn;                    \
 518 })
 519
 520
 521 #endif /* __ALPHA_UACCESS_H */