coregrind/m_libcproc.c

   1
   2 /*--------------------------------------------------------------------*/
   3 /*--- Process-related libc stuff.                     m_libcproc.c ---*/
   4 /*--------------------------------------------------------------------*/
   5
   6 /*
   7    This file is part of Valgrind, a dynamic binary instrumentation
   8    framework.
   9
  10    Copyright (C) 2000-2017 Julian Seward
  11       jseward@acm.org
  12
  13    This program is free software; you can redistribute it and/or
  14    modify it under the terms of the GNU General Public License as
  15    published by the Free Software Foundation; either version 2 of the
  16    License, or (at your option) any later version.
  17
  18    This program is distributed in the hope that it will be useful, but
  19    WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21    General Public License for more details.
  22
  23    You should have received a copy of the GNU General Public License
  24    along with this program; if not, see <http://www.gnu.org/licenses/>.
  25
  26    The GNU General Public License is contained in the file COPYING.
  27 */
  28
  29 #include "pub_core_basics.h"
  30 #include "pub_core_machine.h"    // For VG_(machine_get_VexArchInfo)
  31 #include "pub_core_vki.h"
  32 #include "pub_core_vkiscnums.h"
  33 #include "pub_core_libcbase.h"
  34 #include "pub_core_libcassert.h"
  35 #include "pub_core_libcfile.h"
  36 #include "pub_core_libcprint.h"
  37 #include "pub_core_libcproc.h"
  38 #include "pub_core_libcsignal.h"
  39 #include "pub_core_seqmatch.h"
  40 #include "pub_core_mallocfree.h"
  41 #include "pub_core_syscall.h"
  42 #include "pub_core_xarray.h"
  43 #include "pub_core_clientstate.h"
  44
  45 #if defined(VGO_darwin)
  46 /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */
  47 #include <mach/mach.h>   /* mach_thread_self */
  48 /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */
  49 #endif
  50
  51 /* IMPORTANT: on Darwin it is essential to use the _nocancel versions
  52    of syscalls rather than the vanilla version, if a _nocancel version
  53    is available.  See docs/internals/Darwin-notes.txt for the reason
  54    why. */
  55
  56 /* ---------------------------------------------------------------------
  57    Command line and environment stuff
  58    ------------------------------------------------------------------ */
  59
  60 /* As deduced from sp_at_startup, the client's argc, argv[] and
  61    envp[] as extracted from the client's stack at startup-time. */
  62 HChar** VG_(client_envp) = NULL;
  63
  64 /* Path to library directory */
  65 const HChar *VG_(libdir) = VG_LIBDIR;
  66
  67 const HChar *VG_(LD_PRELOAD_var_name) =
  68 #if defined(VGO_linux) || defined(VGO_solaris)
  69    "LD_PRELOAD";
  70 #elif defined(VGO_darwin)
  71    "DYLD_INSERT_LIBRARIES";
  72 #else
  73 #  error Unknown OS
  74 #endif
  75
  76 /* We do getenv without libc's help by snooping around in
  77    VG_(client_envp) as determined at startup time. */
  78 HChar *VG_(getenv)(const HChar *varname)
  79 {
  80    Int i, n;
  81    vg_assert( VG_(client_envp) );
  82    n = VG_(strlen)(varname);
  83    for (i = 0; VG_(client_envp)[i] != NULL; i++) {
  84       HChar* s = VG_(client_envp)[i];
  85       if (VG_(strncmp)(varname, s, n) == 0 && s[n] == '=') {
  86          return & s[n+1];
  87       }
  88    }
  89    return NULL;
  90 }
  91
  92 /* If free_fn is not NULL, it is called on "unset" environment variable. */
  93 void  VG_(env_unsetenv) ( HChar **env, const HChar *varname,
  94                           void (*free_fn) (void *) )
  95 {
  96    HChar **from, **to;
  97    vg_assert(env);
  98    vg_assert(varname);
  99    to = NULL;
 100    Int len = VG_(strlen)(varname);
 101
 102    for (from = to = env; from && *from; from++) {
 103       if (!(VG_(strncmp)(varname, *from, len) == 0 && (*from)[len] == '=')) {
 104          *to = *from;
 105          to++;
 106       } else if (free_fn != NULL) {
 107          free_fn(*from);
 108       }
 109    }
 110    *to = *from;
 111 }
 112
 113 /* set the environment; returns the old env if a new one was allocated */
 114 HChar **VG_(env_setenv) ( HChar ***envp, const HChar* varname,
 115                           const HChar *val )
 116 {
 117    HChar **env = (*envp);
 118    HChar **cpp;
 119    Int len = VG_(strlen)(varname);
 120    HChar *valstr = VG_(malloc)("libcproc.es.1", len + VG_(strlen)(val) + 2);
 121    HChar **oldenv = NULL;
 122
 123    VG_(sprintf)(valstr, "%s=%s", varname, val);
 124
 125    for (cpp = env; cpp && *cpp; cpp++) {
 126       if (VG_(strncmp)(varname, *cpp, len) == 0 && (*cpp)[len] == '=') {
 127          *cpp = valstr;
 128          return oldenv;
 129       }
 130    }
 131
 132    if (env == NULL) {
 133       env = VG_(malloc)("libcproc.es.2", sizeof(HChar *) * 2);
 134       env[0] = valstr;
 135       env[1] = NULL;
 136
 137       *envp = env;
 138
 139    }  else {
 140       Int envlen = (cpp-env) + 2;
 141       HChar **newenv = VG_(malloc)("libcproc.es.3", envlen * sizeof(HChar *));
 142
 143       for (cpp = newenv; *env; )
 144          *cpp++ = *env++;
 145       *cpp++ = valstr;
 146       *cpp++ = NULL;
 147
 148       oldenv = *envp;
 149
 150       *envp = newenv;
 151    }
 152
 153    return oldenv;
 154 }
 155
 156
 157 /* Walk through a colon-separated environment variable, and remove the
 158    entries which match remove_pattern.  It slides everything down over
 159    the removed entries, and pads the remaining space with '\0'.  It
 160    modifies the entries in place (in the client address space), but it
 161    shouldn't matter too much, since we only do this just before an
 162    execve().
 163
 164    This is also careful to mop up any excess ':'s, since empty strings
 165    delimited by ':' are considered to be '.' in a path.
 166 */
 167 static void mash_colon_env(HChar *varp, const HChar *remove_pattern)
 168 {
 169    HChar *const start = varp;
 170    HChar *entry_start = varp;
 171    HChar *output = varp;
 172
 173    if (varp == NULL)
 174       return;
 175
 176    while(*varp) {
 177       if (*varp == ':') {
 178          HChar prev;
 179          Bool match;
 180
 181          /* This is a bit subtle: we want to match against the entry
 182             we just copied, because it may have overlapped with
 183             itself, junking the original. */
 184
 185          prev = *output;
 186          *output = '\0';
 187
 188          match = VG_(string_match)(remove_pattern, entry_start);
 189
 190          *output = prev;
 191
 192          if (match) {
 193             output = entry_start;
 194             varp++;                     /* skip ':' after removed entry */
 195          } else
 196             entry_start = output+1;     /* entry starts after ':' */
 197       }
 198
 199       if (*varp)
 200          *output++ = *varp++;
 201    }
 202
 203    /* make sure last entry is nul terminated */
 204    *output = '\0';
 205
 206    /* match against the last entry */
 207    if (VG_(string_match)(remove_pattern, entry_start)) {
 208       output = entry_start;
 209       if (output > start) {
 210          /* remove trailing ':' */
 211          output--;
 212          vg_assert(*output == ':');
 213       }
 214    }
 215
 216    /* pad out the left-overs with '\0' */
 217    while(output < varp)
 218       *output++ = '\0';
 219 }
 220
 221
 222 /* Removes all the Valgrind-added stuff from the passed environment.  Used
 223    when starting child processes, so they don't see that added stuff.
 224    If the ro_strings option is set to True then all strings referenced by envp
 225    are considered read-only, which means they will be duplicated before they
 226    are modified.
 227    If free_fn is not NULL, it is called on "unset" environment variables. */
 228 void VG_(env_remove_valgrind_env_stuff)(HChar** envp, Bool ro_strings,
 229                                         void (*free_fn) (void *) )
 230 {
 231    Int i;
 232    HChar* ld_preload_str = NULL;
 233    HChar* ld_library_path_str = NULL;
 234    HChar* dyld_insert_libraries_str = NULL;
 235    HChar* buf;
 236
 237    // Find LD_* variables
 238    // DDD: should probably conditionally compiled some of this:
 239    // - LD_LIBRARY_PATH is universal?
 240    // - LD_PRELOAD is on Linux, not on Darwin, not sure about AIX
 241    // - DYLD_INSERT_LIBRARIES and DYLD_SHARED_REGION are Darwin-only
 242    for (i = 0; envp[i] != NULL; i++) {
 243       if (VG_(strncmp)(envp[i], "LD_PRELOAD=", 11) == 0) {
 244          if (ro_strings)
 245             envp[i] = VG_(strdup)("libcproc.erves.1", envp[i]);
 246          ld_preload_str = &envp[i][11];
 247       }
 248       if (VG_(strncmp)(envp[i], "LD_LIBRARY_PATH=", 16) == 0) {
 249          if (ro_strings)
 250             envp[i] = VG_(strdup)("libcproc.erves.2", envp[i]);
 251          ld_library_path_str = &envp[i][16];
 252       }
 253       if (VG_(strncmp)(envp[i], "DYLD_INSERT_LIBRARIES=", 22) == 0) {
 254          if (ro_strings)
 255             envp[i] = VG_(strdup)("libcproc.erves.3", envp[i]);
 256          dyld_insert_libraries_str = &envp[i][22];
 257       }
 258    }
 259
 260    buf = VG_(malloc)("libcproc.erves.4", VG_(strlen)(VG_(libdir)) + 20);
 261
 262    // Remove Valgrind-specific entries from LD_*.
 263    VG_(sprintf)(buf, "%s*/vgpreload_*.so", VG_(libdir));
 264    mash_colon_env(ld_preload_str, buf);
 265    mash_colon_env(dyld_insert_libraries_str, buf);
 266    VG_(sprintf)(buf, "%s*", VG_(libdir));
 267    mash_colon_env(ld_library_path_str, buf);
 268
 269    // Remove VALGRIND_LAUNCHER variable.
 270    VG_(env_unsetenv)(envp, VALGRIND_LAUNCHER, free_fn);
 271
 272    // Remove DYLD_SHARED_REGION variable.
 273    VG_(env_unsetenv)(envp, "DYLD_SHARED_REGION", free_fn);
 274
 275    // XXX if variable becomes empty, remove it completely?
 276
 277    VG_(free)(buf);
 278 }
 279
 280 /* Resolves filename of VG_(cl_exec_fd) and copies it to the buffer.
 281    Buffer must not be NULL and buf_size must be at least 1.
 282    If buffer is not large enough it is terminated with '\0' only
 283    when 'terminate_with_NUL == True'. */
 284 void VG_(client_fname)(HChar *buffer, SizeT buf_size, Bool terminate_with_NUL)
 285 {
 286    vg_assert(buffer != NULL);
 287    vg_assert(buf_size >= 1);
 288
 289    const HChar *name;
 290    if (VG_(resolve_filename)(VG_(cl_exec_fd), &name)) {
 291       const HChar *n = name + VG_(strlen)(name) - 1;
 292
 293       while (n > name && *n != '/')
 294          n--;
 295       if (n != name)
 296          n++;
 297
 298       VG_(strncpy)(buffer, n, buf_size);
 299       if (terminate_with_NUL)
 300          buffer[buf_size - 1] = '\0';
 301    } else {
 302       buffer[0] = '\0';
 303    }
 304 }
 305
 306 static Bool add_string(HChar *buffer, SizeT *buf_size, const HChar *string)
 307 {
 308    SizeT len = VG_(strlen)(string);
 309    VG_(strncat)(buffer, string, *buf_size);
 310    if (len >= *buf_size - 1) {
 311       *buf_size = 0;
 312       return False;
 313    } else {
 314       *buf_size -= len;
 315       return True;
 316    }
 317 }
 318
 319 /* Concatenates client exename and command line arguments into
 320    the buffer. Buffer must not be NULL and buf_size must be
 321    at least 1. Buffer is always terminated with '\0'. */
 322 void VG_(client_cmd_and_args)(HChar *buffer, SizeT buf_size)
 323 {
 324    vg_assert(buffer != NULL);
 325    vg_assert(buf_size >= 1);
 326
 327    buffer[0] = '\0';
 328
 329    if (add_string(buffer, &buf_size, VG_(args_the_exename)) == False)
 330       return;
 331
 332    Int i;
 333    for (i = 0; i < VG_(sizeXA)(VG_(args_for_client)); i++) {
 334       if (add_string(buffer, &buf_size, " ") == False)
 335          return;
 336
 337       HChar *arg = *(HChar **) VG_(indexXA)(VG_(args_for_client), i);
 338       if (add_string(buffer, &buf_size, arg) == False)
 339          return;
 340    }
 341 }
 342
 343 /* ---------------------------------------------------------------------
 344    Various important syscall wrappers
 345    ------------------------------------------------------------------ */
 346
 347 Int VG_(waitpid)(Int pid, Int *status, Int options)
 348 {
 349 #  if defined(VGO_linux)
 350    SysRes res = VG_(do_syscall4)(__NR_wait4,
 351                                  pid, (UWord)status, options, 0);
 352    return sr_isError(res) ? -1 : sr_Res(res);
 353 #  elif defined(VGO_darwin)
 354    SysRes res = VG_(do_syscall4)(__NR_wait4_nocancel,
 355                                  pid, (UWord)status, options, 0);
 356    return sr_isError(res) ? -1 : sr_Res(res);
 357 #  elif defined(VGO_solaris)
 358    SysRes res;
 359    vki_idtype_t idtype;
 360    vki_id_t id;
 361    vki_siginfo_t info;
 362
 363    /* We need to do a lot of work here. */
 364
 365    if (pid > 0) {
 366       idtype = VKI_P_PID;
 367       id = pid;
 368    }
 369    else if (pid < -1) {
 370       idtype = VKI_P_PGID;
 371       id = -pid;
 372    }
 373    else if (pid == -1) {
 374       idtype = VKI_P_ALL;
 375       id = 0;
 376    }
 377    else {
 378       idtype = VKI_P_PGID;
 379       res = VG_(do_syscall0)(__NR_getpid);
 380       id = sr_ResHI(res);
 381    }
 382
 383    options |= VKI_WEXITED | VKI_WTRAPPED;
 384
 385    res = VG_(do_syscall4)(__NR_waitsys, idtype, id, (UWord)&info, options);
 386    if (sr_isError(res))
 387       return -1;
 388
 389    if (status) {
 390       Int s = info.si_status & 0xff;
 391
 392       switch (info.si_code) {
 393          case VKI_CLD_EXITED:
 394             s <<= 8;
 395             break;
 396          case VKI_CLD_DUMPED:
 397             s |= VKI_WCOREFLG;
 398             break;
 399          case VKI_CLD_KILLED:
 400             break;
 401          case VKI_CLD_TRAPPED:
 402          case VKI_CLD_STOPPED:
 403             s <<= 8;
 404             s |= VKI_WSTOPFLG;
 405             break;
 406          case VKI_CLD_CONTINUED:
 407             s = VKI_WCONTFLG;
 408             break;
 409       }
 410       *status = s;
 411    }
 412
 413    return info.si_pid;
 414 #  else
 415 #    error Unknown OS
 416 #  endif
 417 }
 418
 419 /* clone the environment */
 420 HChar **VG_(env_clone) ( HChar **oldenv )
 421 {
 422    HChar **oldenvp;
 423    HChar **newenvp;
 424    HChar **newenv;
 425    Int  envlen;
 426
 427    vg_assert(oldenv);
 428    for (oldenvp = oldenv; oldenvp && *oldenvp; oldenvp++);
 429
 430    envlen = oldenvp - oldenv + 1;
 431
 432    newenv = VG_(malloc)("libcproc.ec.1", envlen * sizeof(HChar *));
 433
 434    oldenvp = oldenv;
 435    newenvp = newenv;
 436
 437    while (oldenvp && *oldenvp) {
 438       *newenvp++ = *oldenvp++;
 439    }
 440
 441    *newenvp = *oldenvp;
 442
 443    return newenv;
 444 }
 445
 446 void VG_(execv) ( const HChar* filename, const HChar** argv )
 447 {
 448    HChar** envp;
 449    SysRes res;
 450
 451    envp = VG_(env_clone)(VG_(client_envp));
 452    VG_(env_remove_valgrind_env_stuff)( envp, True /*ro_strings*/, NULL );
 453
 454    res = VG_(do_syscall3)(__NR_execve,
 455                           (UWord)filename, (UWord)argv, (UWord)envp);
 456
 457    VG_(printf)("EXEC failed, errno = %lld\n", (Long)sr_Err(res));
 458 }
 459
 460 /* Spawns a new child. Uses either spawn syscall or fork+execv combo. */
 461 Int VG_(spawn) ( const HChar *filename, const HChar **argv )
 462 {
 463    vg_assert(filename != NULL);
 464    vg_assert(argv != NULL);
 465
 466 #  if defined(VGO_solaris) && defined(SOLARIS_SPAWN_SYSCALL)
 467    HChar **envp = VG_(env_clone)(VG_(client_envp));
 468    for (HChar **p = envp; *p != NULL; p++) {
 469       *p = VG_(strdup)("libcproc.s.1", *p);
 470    }
 471    VG_(env_remove_valgrind_env_stuff)(envp, /* ro_strings */ False, VG_(free));
 472
 473    /* Now combine argv and argp into argenv. */
 474    SizeT argenv_size = 1 + 1;
 475    for (const HChar **p = argv; *p != NULL; p++) {
 476       argenv_size += VG_(strlen)(*p) + 2;
 477    }
 478    for (HChar **p = envp; *p != NULL; p++) {
 479       argenv_size += VG_(strlen)(*p) + 2;
 480    }
 481
 482    HChar *argenv = VG_(malloc)("libcproc.s.2", argenv_size);
 483    HChar *current = argenv;
 484 #  define COPY_CHAR_TO_ARGENV(dst, character)  \
 485       do {                                     \
 486          *(dst) = character;                   \
 487          (dst) += 1;                           \
 488       } while (0)
 489 #  define COPY_STRING_TO_ARGENV(dst, src)        \
 490       do {                                       \
 491          COPY_CHAR_TO_ARGENV(dst, '\1');         \
 492          SizeT src_len = VG_(strlen)((src)) + 1; \
 493          VG_(memcpy)((dst), (src), src_len);     \
 494          (dst) += src_len;                       \
 495       } while (0)
 496
 497    for (const HChar **p = argv; *p != NULL; p++) {
 498       COPY_STRING_TO_ARGENV(current, *p);
 499    }
 500    COPY_CHAR_TO_ARGENV(current, '\0');
 501    for (HChar **p = envp; *p != NULL; p++) {
 502       COPY_STRING_TO_ARGENV(current, *p);
 503    }
 504    COPY_CHAR_TO_ARGENV(current, '\0');
 505    vg_assert(current == argenv + argenv_size);
 506 #  undef COPY_CHAR_TO_ARGENV
 507 #  undef COPY_STRING_TOARGENV
 508
 509    SysRes res = VG_(do_syscall5)(__NR_spawn, (UWord) filename, (UWord) NULL, 0,
 510                                  (UWord) argenv, argenv_size);
 511
 512    VG_(free)(argenv);
 513    for (HChar **p = envp; *p != NULL; p++) {
 514       VG_(free)(*p);
 515    }
 516    VG_(free)(envp);
 517
 518    if (sr_isError(res))
 519       return -1;
 520    return sr_Res(res);
 521
 522 #  else
 523
 524    Int pid = VG_(fork)();
 525    if (pid < 0)
 526       return -1;
 527    if (pid == 0) {
 528       /* child */
 529       VG_(execv)(argv[0], argv);
 530
 531       /* If we're still alive here, execv failed. */
 532       VG_(exit)(1);
 533    } else {
 534       return pid;
 535    }
 536 #  endif /* VGO_solaris && SOLARIS_SPAWN_SYSCALL */
 537 }
 538
 539 /* Return -1 if error, else 0.  NOTE does not indicate return code of
 540    child! */
 541 Int VG_(system) ( const HChar* cmd )
 542 {
 543    Int pid;
 544    if (cmd == NULL)
 545       return 1;
 546
 547    const HChar *argv[4] = { "/bin/sh", "-c", cmd, 0 };
 548    pid = VG_(spawn)(argv[0], argv);
 549    if (pid < 0)
 550       return -1;
 551
 552    vg_assert(pid > 0);
 553    /* parent */
 554    /* We have to set SIGCHLD to its default behaviour in order that
 555       VG_(waitpid) works (at least on AIX).  According to the Linux
 556       man page for waitpid:
 557
 558       POSIX.1-2001 specifies that if the disposition of SIGCHLD is
 559       set to SIG_IGN or the SA_NOCLDWAIT flag is set for SIGCHLD
 560       (see sigaction(2)), then children that terminate do not
 561       become zombies and a call to wait() or waitpid() will block
 562       until all children have terminated, and then fail with errno
 563       set to ECHILD.  (The original POSIX standard left the
 564       behaviour of setting SIGCHLD to SIG_IGN unspecified.)
 565    */
 566    Int ir, zzz;
 567    vki_sigaction_toK_t sa, sa2;
 568    vki_sigaction_fromK_t saved_sa;
 569    VG_(memset)( &sa, 0, sizeof(sa) );
 570    VG_(sigemptyset)(&sa.sa_mask);
 571    sa.ksa_handler = VKI_SIG_DFL;
 572    sa.sa_flags    = 0;
 573    ir = VG_(sigaction)(VKI_SIGCHLD, &sa, &saved_sa);
 574    vg_assert(ir == 0);
 575
 576    zzz = VG_(waitpid)(pid, NULL, 0);
 577
 578    VG_(convert_sigaction_fromK_to_toK)( &saved_sa, &sa2 );
 579    ir = VG_(sigaction)(VKI_SIGCHLD, &sa2, NULL);
 580    vg_assert(ir == 0);
 581    return zzz == -1 ? -1 : 0;
 582 }
 583
 584 Int VG_(sysctl)(Int *name, UInt namelen, void *oldp, SizeT *oldlenp, void *newp, SizeT newlen)
 585 {
 586    SysRes res;
 587 #  if defined(VGO_darwin)
 588    res = VG_(do_syscall6)(__NR___sysctl,
 589                            (UWord)name, namelen, (UWord)oldp, (UWord)oldlenp, (UWord)newp, newlen);
 590 #  else
 591    res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 592 #  endif
 593    return sr_isError(res) ? -1 : sr_Res(res);
 594 }
 595
 596 /* ---------------------------------------------------------------------
 597    Resource limits
 598    ------------------------------------------------------------------ */
 599
 600 /* Support for getrlimit. */
 601 Int VG_(getrlimit) (Int resource, struct vki_rlimit *rlim)
 602 {
 603    SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 604    /* res = getrlimit( resource, rlim ); */
 605 #  ifdef __NR_ugetrlimit
 606    res = VG_(do_syscall2)(__NR_ugetrlimit, resource, (UWord)rlim);
 607 #  endif
 608    if (sr_isError(res) && sr_Err(res) == VKI_ENOSYS)
 609       res = VG_(do_syscall2)(__NR_getrlimit, resource, (UWord)rlim);
 610    return sr_isError(res) ? -1 : sr_Res(res);
 611 }
 612
 613
 614 /* Support for setrlimit. */
 615 Int VG_(setrlimit) (Int resource, const struct vki_rlimit *rlim)
 616 {
 617    SysRes res;
 618    /* res = setrlimit( resource, rlim ); */
 619    res = VG_(do_syscall2)(__NR_setrlimit, resource, (UWord)rlim);
 620    return sr_isError(res) ? -1 : sr_Res(res);
 621 }
 622
 623 /* Support for prctl. */
 624 Int VG_(prctl) (Int option,
 625                 ULong arg2, ULong arg3, ULong arg4, ULong arg5)
 626 {
 627    SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 628 #  if defined(VGO_linux)
 629    /* res = prctl( option, arg2, arg3, arg4, arg5 ); */
 630    res = VG_(do_syscall5)(__NR_prctl, (UWord) option,
 631                           (UWord) arg2, (UWord) arg3, (UWord) arg4,
 632                           (UWord) arg5);
 633 #  endif
 634
 635    return sr_isError(res) ? -1 : sr_Res(res);
 636 }
 637
 638 /* ---------------------------------------------------------------------
 639    pids, etc
 640    ------------------------------------------------------------------ */
 641
 642 Int VG_(gettid)(void)
 643 {
 644 #  if defined(VGO_linux)
 645    SysRes res = VG_(do_syscall0)(__NR_gettid);
 646
 647    if (sr_isError(res) && sr_Res(res) == VKI_ENOSYS) {
 648       HChar pid[16];
 649       /*
 650        * The gettid system call does not exist. The obvious assumption
 651        * to make at this point would be that we are running on an older
 652        * system where the getpid system call actually returns the ID of
 653        * the current thread.
 654        *
 655        * Unfortunately it seems that there are some systems with a kernel
 656        * where getpid has been changed to return the ID of the thread group
 657        * leader but where the gettid system call has not yet been added.
 658        *
 659        * So instead of calling getpid here we use readlink to see where
 660        * the /proc/self link is pointing...
 661        */
 662
 663 #     if defined(VGP_arm64_linux)
 664       res = VG_(do_syscall4)(__NR_readlinkat, VKI_AT_FDCWD,
 665                              (UWord)"/proc/self",
 666                              (UWord)pid, sizeof(pid));
 667 #     else
 668       res = VG_(do_syscall3)(__NR_readlink, (UWord)"/proc/self",
 669                              (UWord)pid, sizeof(pid));
 670 #     endif
 671       if (!sr_isError(res) && sr_Res(res) > 0) {
 672          HChar* s;
 673          pid[sr_Res(res)] = '\0';
 674          res = VG_(mk_SysRes_Success)(  VG_(strtoll10)(pid, &s) );
 675          if (*s != '\0') {
 676             VG_(message)(Vg_DebugMsg,
 677                "Warning: invalid file name linked to by /proc/self: %s\n",
 678                pid);
 679          }
 680       }
 681    }
 682
 683    return sr_Res(res);
 684
 685 #  elif defined(VGO_darwin)
 686    // Darwin's gettid syscall is something else.
 687    // Use Mach thread ports for lwpid instead.
 688    return mach_thread_self();
 689
 690 #  elif defined(VGO_solaris)
 691    SysRes res = VG_(do_syscall0)(__NR_lwp_self);
 692    return sr_Res(res);
 693
 694 #  else
 695 #    error "Unknown OS"
 696 #  endif
 697 }
 698
 699 /* You'd be amazed how many places need to know the current pid. */
 700 Int VG_(getpid) ( void )
 701 {
 702    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 703    return sr_Res( VG_(do_syscall0)(__NR_getpid) );
 704 }
 705
 706 Int VG_(getpgrp) ( void )
 707 {
 708    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 709 #  if defined(VGP_arm64_linux)
 710    return sr_Res( VG_(do_syscall1)(__NR_getpgid, 0) );
 711 #  elif defined(VGO_linux) || defined(VGO_darwin)
 712    return sr_Res( VG_(do_syscall0)(__NR_getpgrp) );
 713 #  elif defined(VGO_solaris)
 714    /* Uses the shared pgrpsys syscall, 0 for the getpgrp variant. */
 715    return sr_Res( VG_(do_syscall1)(__NR_pgrpsys, 0) );
 716 #  else
 717 #    error Unknown OS
 718 #  endif
 719 }
 720
 721 Int VG_(getppid) ( void )
 722 {
 723    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 724 #  if defined(VGO_linux) || defined(VGO_darwin)
 725    return sr_Res( VG_(do_syscall0)(__NR_getppid) );
 726 #  elif defined(VGO_solaris)
 727    /* Uses the shared getpid/getppid syscall, val2 contains a parent pid. */
 728    return sr_ResHI( VG_(do_syscall0)(__NR_getpid) );
 729 #  else
 730 #    error Unknown OS
 731 #  endif
 732 }
 733
 734 Int VG_(geteuid) ( void )
 735 {
 736    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 737 #  if defined(VGO_linux) || defined(VGO_darwin)
 738    {
 739 #     if defined(__NR_geteuid32)
 740       // We use the 32-bit version if it's supported.  Otherwise, IDs greater
 741       // than 65536 cause problems, as bug #151209 showed.
 742       return sr_Res( VG_(do_syscall0)(__NR_geteuid32) );
 743 #     else
 744       return sr_Res( VG_(do_syscall0)(__NR_geteuid) );
 745 #     endif
 746    }
 747 #  elif defined(VGO_solaris)
 748    /* Uses the shared getuid/geteuid syscall, val2 contains the effective
 749       uid. */
 750    return sr_ResHI( VG_(do_syscall0)(__NR_getuid) );
 751 #  else
 752 #    error Unknown OS
 753 #  endif
 754 }
 755
 756 Int VG_(getegid) ( void )
 757 {
 758 #  if defined(VGO_linux) || defined(VGO_darwin)
 759    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 760 #    if defined(__NR_getegid32)
 761    // We use the 32-bit version if it's supported.  Otherwise, IDs greater
 762    // than 65536 cause problems, as bug #151209 showed.
 763    return sr_Res( VG_(do_syscall0)(__NR_getegid32) );
 764 #    else
 765    return sr_Res( VG_(do_syscall0)(__NR_getegid) );
 766 #    endif
 767
 768 #  elif defined(VGO_solaris)
 769    /* Uses the shared getgid/getegid syscall, val2 contains the effective
 770       gid. */
 771    return sr_ResHI( VG_(do_syscall0)(__NR_getgid) );
 772 #  else
 773 #    error Unknown OS
 774 #  endif
 775 }
 776
 777 /* Get supplementary groups into list[0 .. size-1].  Returns the
 778    number of groups written, or -1 if error.  Note that in order to be
 779    portable, the groups are 32-bit unsigned ints regardless of the
 780    platform.
 781    As a special case, if size == 0 the function returns the number of
 782    groups leaving list untouched. */
 783 Int VG_(getgroups)( Int size, UInt* list )
 784 {
 785    if (size < 0) return -1;
 786
 787 #  if defined(VGP_x86_linux) || defined(VGP_ppc32_linux) \
 788       || defined(VGP_mips64_linux)
 789    Int    i;
 790    SysRes sres;
 791    UShort list16[size];
 792    sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list16);
 793    if (sr_isError(sres))
 794       return -1;
 795    if (size != 0) {
 796       for (i = 0; i < sr_Res(sres); i++)
 797          list[i] = (UInt)list16[i];
 798    }
 799    return sr_Res(sres);
 800
 801 #  elif defined(VGP_amd64_linux) || defined(VGP_arm_linux) \
 802         || defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)  \
 803         || defined(VGO_darwin) || defined(VGP_s390x_linux)    \
 804         || defined(VGP_mips32_linux) || defined(VGP_arm64_linux) \
 805         || defined(VGO_solaris)
 806    SysRes sres;
 807    sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list);
 808    if (sr_isError(sres))
 809       return -1;
 810    return sr_Res(sres);
 811
 812 #  else
 813 #     error "VG_(getgroups): needs implementation on this platform"
 814 #  endif
 815 }
 816
 817 /* ---------------------------------------------------------------------
 818    Process tracing
 819    ------------------------------------------------------------------ */
 820
 821 Int VG_(ptrace) ( Int request, Int pid, void *addr, void *data )
 822 {
 823    SysRes res;
 824 #  if defined(VGO_linux) || defined(VGO_darwin)
 825    res = VG_(do_syscall4)(__NR_ptrace, request, pid, (UWord)addr, (UWord)data);
 826 #  elif defined(VGO_solaris)
 827    /* There is no ptrace syscall on Solaris.  Such requests has to be
 828       implemented using the /proc interface.  Callers of VG_(ptrace) should
 829       ensure that this function is not reached on Solaris, i.e. they must
 830       provide a special code for Solaris for whatever feature they provide. */
 831    I_die_here;
 832 #  else
 833 #    error Unknown OS
 834 #  endif
 835    if (sr_isError(res))
 836       return -1;
 837    return sr_Res(res);
 838 }
 839
 840 /* ---------------------------------------------------------------------
 841    Fork
 842    ------------------------------------------------------------------ */
 843
 844 Int VG_(fork) ( void )
 845 {
 846 #  if defined(VGP_arm64_linux)
 847    SysRes res;
 848    res = VG_(do_syscall5)(__NR_clone, VKI_SIGCHLD,
 849                           (UWord)NULL, (UWord)NULL, (UWord)NULL, (UWord)NULL);
 850    if (sr_isError(res))
 851       return -1;
 852    return sr_Res(res);
 853
 854 #  elif defined(VGO_linux)
 855    SysRes res;
 856    res = VG_(do_syscall0)(__NR_fork);
 857    if (sr_isError(res))
 858       return -1;
 859    return sr_Res(res);
 860
 861 #  elif defined(VGO_darwin)
 862    SysRes res;
 863    res = VG_(do_syscall0)(__NR_fork); /* __NR_fork is UX64 */
 864    if (sr_isError(res))
 865       return -1;
 866    /* on success: wLO = child pid; wHI = 1 for child, 0 for parent */
 867    if (sr_ResHI(res) != 0) {
 868       return 0;  /* this is child: return 0 instead of child pid */
 869    }
 870    return sr_Res(res);
 871
 872 #  elif defined(VGO_solaris)
 873    /* Using fork() on Solaris is not really the best thing to do. Solaris
 874       does not do memory overcommitment so fork() can fail if there is not
 875       enough memory to copy the current process into a new one.
 876       Prefer to use VG_(spawn)() over VG_(fork)() + VG_(execv)(). */
 877    SysRes res;
 878    res = VG_(do_syscall2)(__NR_forksys, 0 /*subcode (fork)*/, 0 /*flags*/);
 879    if (sr_isError(res))
 880       return -1;
 881    /* On success:
 882         val = a pid of the child in the parent, a pid of the parent in the
 883               child,
 884         val2 = 0 in the parent process, 1 in the child process. */
 885    if (sr_ResHI(res) != 0) {
 886       return 0;
 887    }
 888    return sr_Res(res);
 889
 890 #  else
 891 #    error "Unknown OS"
 892 #  endif
 893 }
 894
 895 /* ---------------------------------------------------------------------
 896    Timing stuff
 897    ------------------------------------------------------------------ */
 898
 899 UInt VG_(read_millisecond_timer) ( void )
 900 {
 901    /* 'now' and 'base' are in microseconds */
 902    static ULong base = 0;
 903    ULong  now;
 904
 905 #  if defined(VGO_linux) || defined(VGO_solaris)
 906    { SysRes res;
 907      struct vki_timespec ts_now;
 908      res = VG_(do_syscall2)(__NR_clock_gettime, VKI_CLOCK_MONOTONIC,
 909                             (UWord)&ts_now);
 910      if (sr_isError(res) == 0) {
 911         now = ts_now.tv_sec * 1000000ULL + ts_now.tv_nsec / 1000;
 912      } else {
 913        struct vki_timeval tv_now;
 914        /* Note: On Solaris, this syscall takes only one parameter but the
 915           extra dummy one does not cause any harm. */
 916        res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
 917        vg_assert(! sr_isError(res));
 918        now = tv_now.tv_sec * 1000000ULL + tv_now.tv_usec;
 919      }
 920    }
 921
 922 #  elif defined(VGO_darwin)
 923    // Weird: it seems that gettimeofday() doesn't fill in the timeval, but
 924    // rather returns the tv_sec as the low 32 bits of the result and the
 925    // tv_usec as the high 32 bits of the result.  (But the timeval cannot be
 926    // NULL!)  See bug 200990.
 927    { SysRes res;
 928      struct vki_timeval tv_now = { 0, 0 };
 929      res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
 930      vg_assert(! sr_isError(res));
 931      now = sr_Res(res) * 1000000ULL + sr_ResHI(res);
 932    }
 933
 934 #  else
 935 #    error "Unknown OS"
 936 #  endif
 937
 938    /* COMMON CODE */
 939    if (base == 0)
 940       base = now;
 941
 942    return (now - base) / 1000;
 943 }
 944
 945 Int VG_(gettimeofday)(struct vki_timeval *tv, struct vki_timezone *tz)
 946 {
 947    SysRes res;
 948    res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)tv, (UWord)tz);
 949
 950    if (! sr_isError(res)) return 0;
 951
 952    /* Make sure, argument values are deterministic upon failure */
 953    if (tv) *tv = (struct vki_timeval){ .tv_sec = 0, .tv_usec = 0 };
 954    if (tz) *tz = (struct vki_timezone){ .tz_minuteswest = 0, .tz_dsttime = 0 };
 955
 956    return -1;
 957 }
 958
 959 UInt VG_(get_user_milliseconds)(void)
 960 {
 961    UInt res = 0;
 962 #  if defined(VGO_linux)
 963    {
 964       struct vki_rusage ru;
 965       VG_(memset)(&ru, 0, sizeof(ru));
 966       SysRes sr = VG_(do_syscall2)(__NR_getrusage, VKI_RUSAGE_SELF, (UWord)&ru);
 967       if (!sr_isError(sr)) {
 968          res = ru.ru_utime.tv_sec * 1000 + ru.ru_utime.tv_usec / 1000;
 969       }
 970    }
 971
 972 #  elif defined(VGO_solaris)
 973    {
 974       struct vki_rusage ru;
 975       VG_(memset)(&ru, 0, sizeof(ru));
 976       SysRes sr = VG_(do_syscall2)(__NR_rusagesys, VKI__RUSAGESYS_GETRUSAGE,
 977                                    (UWord) &ru);
 978       if (!sr_isError(sr)) {
 979          res = ru.ru_utime.tv_sec * 1000 + ru.ru_utime.tv_usec / 1000;
 980       }
 981    }
 982
 983 #  elif defined(VGO_darwin)
 984    res = 0;
 985
 986 #  else
 987 #    error "Unknown OS"
 988 #  endif
 989
 990    return res;
 991 }
 992
 993
 994 /* ---------------------------------------------------------------------
 995    atfork()
 996    ------------------------------------------------------------------ */
 997
 998 struct atfork {
 999    vg_atfork_t  pre;
1000    vg_atfork_t  parent;
1001    vg_atfork_t  child;
1002 };
1003
1004 #define VG_MAX_ATFORK 10
1005
1006 static struct atfork atforks[VG_MAX_ATFORK];
1007 static Int n_atfork = 0;
1008
1009 void VG_(atfork)(vg_atfork_t pre, vg_atfork_t parent, vg_atfork_t child)
1010 {
1011    Int i;
1012
1013    for (i = 0; i < n_atfork; i++) {
1014       if (atforks[i].pre == pre &&
1015           atforks[i].parent == parent &&
1016           atforks[i].child == child)
1017          return;
1018    }
1019
1020    if (n_atfork >= VG_MAX_ATFORK)
1021       VG_(core_panic)(
1022          "Too many VG_(atfork) handlers requested: raise VG_MAX_ATFORK");
1023
1024    atforks[n_atfork].pre    = pre;
1025    atforks[n_atfork].parent = parent;
1026    atforks[n_atfork].child  = child;
1027
1028    n_atfork++;
1029 }
1030
1031 void VG_(do_atfork_pre)(ThreadId tid)
1032 {
1033    Int i;
1034
1035    for (i = 0; i < n_atfork; i++)
1036       if (atforks[i].pre != NULL)
1037          (*atforks[i].pre)(tid);
1038 }
1039
1040 void VG_(do_atfork_parent)(ThreadId tid)
1041 {
1042    Int i;
1043
1044    for (i = 0; i < n_atfork; i++)
1045       if (atforks[i].parent != NULL)
1046          (*atforks[i].parent)(tid);
1047 }
1048
1049 void VG_(do_atfork_child)(ThreadId tid)
1050 {
1051    Int i;
1052
1053    for (i = 0; i < n_atfork; i++)
1054       if (atforks[i].child != NULL)
1055          (*atforks[i].child)(tid);
1056 }
1057
1058
1059 /* ---------------------------------------------------------------------
1060    icache invalidation
1061    ------------------------------------------------------------------ */
1062
1063 void VG_(invalidate_icache) ( void *ptr, SizeT nbytes )
1064 {
1065    if (nbytes == 0) return;    // nothing to do
1066
1067    // Get cache info
1068    VexArchInfo vai;
1069    VG_(machine_get_VexArchInfo)(NULL, &vai);
1070
1071    // If I-caches are coherent, nothing needs to be done here
1072    if (vai.hwcache_info.icaches_maintain_coherence) return;
1073
1074 #  if defined(VGA_ppc32) || defined(VGA_ppc64be) || defined(VGA_ppc64le)
1075    Addr startaddr = (Addr) ptr;
1076    Addr endaddr   = startaddr + nbytes;
1077    Addr cls;
1078    Addr addr;
1079
1080    cls = vai.ppc_icache_line_szB;
1081
1082    /* Stay sane .. */
1083    vg_assert(cls == 16 || cls == 32 || cls == 64 || cls == 128);
1084
1085    startaddr &= ~(cls - 1);
1086    for (addr = startaddr; addr < endaddr; addr += cls) {
1087       __asm__ __volatile__("dcbst 0,%0" : : "r" (addr));
1088    }
1089    __asm__ __volatile__("sync");
1090    for (addr = startaddr; addr < endaddr; addr += cls) {
1091       __asm__ __volatile__("icbi 0,%0" : : "r" (addr));
1092    }
1093    __asm__ __volatile__("sync; isync");
1094
1095 #  elif defined(VGP_arm_linux)
1096    /* ARM cache flushes are privileged, so we must defer to the kernel. */
1097    Addr startaddr = (Addr) ptr;
1098    Addr endaddr   = startaddr + nbytes;
1099    VG_(do_syscall2)(__NR_ARM_cacheflush, startaddr, endaddr);
1100
1101 #  elif defined(VGP_arm64_linux)
1102    // This arm64_linux section of this function VG_(invalidate_icache)
1103    // is copied from
1104    // https://github.com/armvixl/vixl/blob/master/src/a64/cpu-a64.cc
1105    // which has the following copyright notice:
1106    /*
1107    Copyright 2013, ARM Limited
1108    All rights reserved.
1109
1110    Redistribution and use in source and binary forms, with or without
1111    modification, are permitted provided that the following conditions are met:
1112
1113    * Redistributions of source code must retain the above copyright notice,
1114      this list of conditions and the following disclaimer.
1115    * Redistributions in binary form must reproduce the above copyright notice,
1116      this list of conditions and the following disclaimer in the documentation
1117      and/or other materials provided with the distribution.
1118    * Neither the name of ARM Limited nor the names of its contributors may be
1119      used to endorse or promote products derived from this software without
1120      specific prior written permission.
1121
1122    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
1123    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1124    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1125    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
1126    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1127    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
1128    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
1129    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
1130    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1131    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1132    */
1133
1134    // Ask what the I and D line sizes are
1135    UInt cache_type_register;
1136    // Copy the content of the cache type register to a core register.
1137    __asm__ __volatile__ ("mrs %[ctr], ctr_el0" // NOLINT
1138                          : [ctr] "=r" (cache_type_register));
1139
1140    const Int kDCacheLineSizeShift = 16;
1141    const Int kICacheLineSizeShift = 0;
1142    const UInt kDCacheLineSizeMask = 0xf << kDCacheLineSizeShift;
1143    const UInt kICacheLineSizeMask = 0xf << kICacheLineSizeShift;
1144
1145    // The cache type register holds the size of the I and D caches as a power of
1146    // two.
1147    const UInt dcache_line_size_power_of_two =
1148        (cache_type_register & kDCacheLineSizeMask) >> kDCacheLineSizeShift;
1149    const UInt icache_line_size_power_of_two =
1150        (cache_type_register & kICacheLineSizeMask) >> kICacheLineSizeShift;
1151
1152    const UInt dcache_line_size_ = 4 * (1 << dcache_line_size_power_of_two);
1153    const UInt icache_line_size_ = 4 * (1 << icache_line_size_power_of_two);
1154
1155    Addr start = (Addr)ptr;
1156    // Sizes will be used to generate a mask big enough to cover a pointer.
1157    Addr dsize = (Addr)dcache_line_size_;
1158    Addr isize = (Addr)icache_line_size_;
1159
1160    // Cache line sizes are always a power of 2.
1161    Addr dstart = start & ~(dsize - 1);
1162    Addr istart = start & ~(isize - 1);
1163    Addr end    = start + nbytes;
1164
1165    __asm__ __volatile__ (
1166      // Clean every line of the D cache containing the target data.
1167      "0: \n\t"
1168      // dc : Data Cache maintenance
1169      // c : Clean
1170      // va : by (Virtual) Address
1171      // u : to the point of Unification
1172      // The point of unification for a processor is the point by which the
1173      // instruction and data caches are guaranteed to see the same copy of a
1174      // memory location. See ARM DDI 0406B page B2-12 for more information.
1175      "dc cvau, %[dline] \n\t"
1176      "add %[dline], %[dline], %[dsize] \n\t"
1177      "cmp %[dline], %[end] \n\t"
1178      "b.lt 0b \n\t"
1179      // Barrier to make sure the effect of the code above is visible to the rest
1180      // of the world.
1181      // dsb : Data Synchronisation Barrier
1182      // ish : Inner SHareable domain
1183      // The point of unification for an Inner Shareable shareability domain is
1184      // the point by which the instruction and data caches of all the processors
1185      // in that Inner Shareable shareability domain are guaranteed to see the
1186      // same copy of a memory location. See ARM DDI 0406B page B2-12 for more
1187      // information.
1188      "dsb ish \n\t"
1189      // Invalidate every line of the I cache containing the target data.
1190      "1: \n\t"
1191      // ic : instruction cache maintenance
1192      // i : invalidate
1193      // va : by address
1194      // u : to the point of unification
1195      "ic ivau, %[iline] \n\t"
1196      "add %[iline], %[iline], %[isize] \n\t"
1197      "cmp %[iline], %[end] \n\t"
1198      "b.lt 1b \n\t"
1199      // Barrier to make sure the effect of the code above is visible to the rest
1200      // of the world.
1201      "dsb ish \n\t"
1202      // Barrier to ensure any prefetching which happened before this code is
1203      // discarded.
1204      // isb : Instruction Synchronisation Barrier
1205      "isb \n\t"
1206      : [dline] "+r" (dstart),
1207        [iline] "+r" (istart)
1208      : [dsize] "r" (dsize),
1209        [isize] "r" (isize),
1210        [end] "r" (end)
1211      // This code does not write to memory but without the dependency gcc might
1212      // move this code before the code is generated.
1213      : "cc", "memory"
1214    );
1215
1216 #  elif defined(VGA_mips32) || defined(VGA_mips64)
1217    SysRes sres = VG_(do_syscall3)(__NR_cacheflush, (UWord) ptr,
1218                                  (UWord) nbytes, (UWord) 3);
1219    vg_assert( !sr_isError(sres) );
1220
1221 #  endif
1222 }
1223
1224
1225 /* ---------------------------------------------------------------------
1226    dcache flushing
1227    ------------------------------------------------------------------ */
1228
1229 void VG_(flush_dcache) ( void *ptr, SizeT nbytes )
1230 {
1231    /* Currently this is only required on ARM64. */
1232 #  if defined(VGA_arm64)
1233    Addr startaddr = (Addr) ptr;
1234    Addr endaddr   = startaddr + nbytes;
1235    Addr cls;
1236    Addr addr;
1237
1238    ULong ctr_el0;
1239    __asm__ __volatile__ ("mrs %0, ctr_el0" : "=r"(ctr_el0));
1240    cls = 4 * (1ULL << (0xF & (ctr_el0 >> 16)));
1241
1242    /* Stay sane .. */
1243    vg_assert(cls == 64 || cls == 128);
1244
1245    startaddr &= ~(cls - 1);
1246    for (addr = startaddr; addr < endaddr; addr += cls) {
1247       __asm__ __volatile__("dc cvau, %0" : : "r" (addr));
1248    }
1249    __asm__ __volatile__("dsb ish");
1250 #  endif
1251 }
1252
1253 /*--------------------------------------------------------------------*/
1254 /*--- end                                                          ---*/
1255 /*--------------------------------------------------------------------*/