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