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, write to the Free Software
  25    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  26    02111-1307, USA.
  27
  28    The GNU General Public License is contained in the file COPYING.
  29 */
  30
  31 #include "pub_core_basics.h"
  32 #include "pub_core_machine.h"    // For VG_(machine_get_VexArchInfo)
  33 #include "pub_core_vki.h"
  34 #include "pub_core_vkiscnums.h"
  35 #include "pub_core_libcbase.h"
  36 #include "pub_core_libcassert.h"
  37 #include "pub_core_libcfile.h"
  38 #include "pub_core_libcprint.h"
  39 #include "pub_core_libcproc.h"
  40 #include "pub_core_libcsignal.h"
  41 #include "pub_core_seqmatch.h"
  42 #include "pub_core_mallocfree.h"
  43 #include "pub_core_syscall.h"
  44 #include "pub_core_xarray.h"
  45 #include "pub_core_clientstate.h"
  46
  47 #if defined(VGO_darwin)
  48 /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */
  49 #include <mach/mach.h>   /* mach_thread_self */
  50 /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */
  51 #endif
  52
  53 /* IMPORTANT: on Darwin it is essential to use the _nocancel versions
  54    of syscalls rather than the vanilla version, if a _nocancel version
  55    is available.  See docs/internals/Darwin-notes.txt for the reason
  56    why. */
  57
  58 /* ---------------------------------------------------------------------
  59    Command line and environment stuff
  60    ------------------------------------------------------------------ */
  61
  62 /* As deduced from sp_at_startup, the client's argc, argv[] and
  63    envp[] as extracted from the client's stack at startup-time. */
  64 HChar** VG_(client_envp) = NULL;
  65
  66 /* Path to library directory */
  67 const HChar *VG_(libdir) = VG_LIBDIR;
  68
  69 const HChar *VG_(LD_PRELOAD_var_name) =
  70 #if defined(VGO_linux) || defined(VGO_solaris)
  71    "LD_PRELOAD";
  72 #elif defined(VGO_darwin)
  73    "DYLD_INSERT_LIBRARIES";
  74 #else
  75 #  error Unknown OS
  76 #endif
  77
  78 /* We do getenv without libc's help by snooping around in
  79    VG_(client_envp) as determined at startup time. */
  80 HChar *VG_(getenv)(const HChar *varname)
  81 {
  82    Int i, n;
  83    vg_assert( VG_(client_envp) );
  84    n = VG_(strlen)(varname);
  85    for (i = 0; VG_(client_envp)[i] != NULL; i++) {
  86       HChar* s = VG_(client_envp)[i];
  87       if (VG_(strncmp)(varname, s, n) == 0 && s[n] == '=') {
  88          return & s[n+1];
  89       }
  90    }
  91    return NULL;
  92 }
  93
  94 /* If free_fn is not NULL, it is called on "unset" environment variable. */
  95 void  VG_(env_unsetenv) ( HChar **env, const HChar *varname,
  96                           void (*free_fn) (void *) )
  97 {
  98    HChar **from, **to;
  99    vg_assert(env);
 100    vg_assert(varname);
 101    to = NULL;
 102    Int len = VG_(strlen)(varname);
 103
 104    for (from = to = env; from && *from; from++) {
 105       if (!(VG_(strncmp)(varname, *from, len) == 0 && (*from)[len] == '=')) {
 106          *to = *from;
 107          to++;
 108       } else if (free_fn != NULL) {
 109          free_fn(*from);
 110       }
 111    }
 112    *to = *from;
 113 }
 114
 115 /* set the environment; returns the old env if a new one was allocated */
 116 HChar **VG_(env_setenv) ( HChar ***envp, const HChar* varname,
 117                           const HChar *val )
 118 {
 119    HChar **env = (*envp);
 120    HChar **cpp;
 121    Int len = VG_(strlen)(varname);
 122    HChar *valstr = VG_(malloc)("libcproc.es.1", len + VG_(strlen)(val) + 2);
 123    HChar **oldenv = NULL;
 124
 125    VG_(sprintf)(valstr, "%s=%s", varname, val);
 126
 127    for (cpp = env; cpp && *cpp; cpp++) {
 128       if (VG_(strncmp)(varname, *cpp, len) == 0 && (*cpp)[len] == '=') {
 129          *cpp = valstr;
 130          return oldenv;
 131       }
 132    }
 133
 134    if (env == NULL) {
 135       env = VG_(malloc)("libcproc.es.2", sizeof(HChar *) * 2);
 136       env[0] = valstr;
 137       env[1] = NULL;
 138
 139       *envp = env;
 140
 141    }  else {
 142       Int envlen = (cpp-env) + 2;
 143       HChar **newenv = VG_(malloc)("libcproc.es.3", envlen * sizeof(HChar *));
 144
 145       for (cpp = newenv; *env; )
 146          *cpp++ = *env++;
 147       *cpp++ = valstr;
 148       *cpp++ = NULL;
 149
 150       oldenv = *envp;
 151
 152       *envp = newenv;
 153    }
 154
 155    return oldenv;
 156 }
 157
 158
 159 /* Walk through a colon-separated environment variable, and remove the
 160    entries which match remove_pattern.  It slides everything down over
 161    the removed entries, and pads the remaining space with '\0'.  It
 162    modifies the entries in place (in the client address space), but it
 163    shouldn't matter too much, since we only do this just before an
 164    execve().
 165
 166    This is also careful to mop up any excess ':'s, since empty strings
 167    delimited by ':' are considered to be '.' in a path.
 168 */
 169 static void mash_colon_env(HChar *varp, const HChar *remove_pattern)
 170 {
 171    HChar *const start = varp;
 172    HChar *entry_start = varp;
 173    HChar *output = varp;
 174
 175    if (varp == NULL)
 176       return;
 177
 178    while(*varp) {
 179       if (*varp == ':') {
 180          HChar prev;
 181          Bool match;
 182
 183          /* This is a bit subtle: we want to match against the entry
 184             we just copied, because it may have overlapped with
 185             itself, junking the original. */
 186
 187          prev = *output;
 188          *output = '\0';
 189
 190          match = VG_(string_match)(remove_pattern, entry_start);
 191
 192          *output = prev;
 193
 194          if (match) {
 195             output = entry_start;
 196             varp++;                     /* skip ':' after removed entry */
 197          } else
 198             entry_start = output+1;     /* entry starts after ':' */
 199       }
 200
 201       if (*varp)
 202          *output++ = *varp++;
 203    }
 204
 205    /* make sure last entry is nul terminated */
 206    *output = '\0';
 207
 208    /* match against the last entry */
 209    if (VG_(string_match)(remove_pattern, entry_start)) {
 210       output = entry_start;
 211       if (output > start) {
 212          /* remove trailing ':' */
 213          output--;
 214          vg_assert(*output == ':');
 215       }
 216    }
 217
 218    /* pad out the left-overs with '\0' */
 219    while(output < varp)
 220       *output++ = '\0';
 221 }
 222
 223
 224 /* Removes all the Valgrind-added stuff from the passed environment.  Used
 225    when starting child processes, so they don't see that added stuff.
 226    If the ro_strings option is set to True then all strings referenced by envp
 227    are considered read-only, which means they will be duplicated before they
 228    are modified.
 229    If free_fn is not NULL, it is called on "unset" environment variables. */
 230 void VG_(env_remove_valgrind_env_stuff)(HChar** envp, Bool ro_strings,
 231                                         void (*free_fn) (void *) )
 232 {
 233    Int i;
 234    HChar* ld_preload_str = NULL;
 235    HChar* ld_library_path_str = NULL;
 236    HChar* dyld_insert_libraries_str = NULL;
 237    HChar* buf;
 238
 239    // Find LD_* variables
 240    // DDD: should probably conditionally compiled some of this:
 241    // - LD_LIBRARY_PATH is universal?
 242    // - LD_PRELOAD is on Linux, not on Darwin, not sure about AIX
 243    // - DYLD_INSERT_LIBRARIES and DYLD_SHARED_REGION are Darwin-only
 244    for (i = 0; envp[i] != NULL; i++) {
 245       if (VG_(strncmp)(envp[i], "LD_PRELOAD=", 11) == 0) {
 246          if (ro_strings)
 247             envp[i] = VG_(strdup)("libcproc.erves.1", envp[i]);
 248          ld_preload_str = &envp[i][11];
 249       }
 250       if (VG_(strncmp)(envp[i], "LD_LIBRARY_PATH=", 16) == 0) {
 251          if (ro_strings)
 252             envp[i] = VG_(strdup)("libcproc.erves.2", envp[i]);
 253          ld_library_path_str = &envp[i][16];
 254       }
 255       if (VG_(strncmp)(envp[i], "DYLD_INSERT_LIBRARIES=", 22) == 0) {
 256          if (ro_strings)
 257             envp[i] = VG_(strdup)("libcproc.erves.3", envp[i]);
 258          dyld_insert_libraries_str = &envp[i][22];
 259       }
 260    }
 261
 262    buf = VG_(malloc)("libcproc.erves.4", VG_(strlen)(VG_(libdir)) + 20);
 263
 264    // Remove Valgrind-specific entries from LD_*.
 265    VG_(sprintf)(buf, "%s*/vgpreload_*.so", VG_(libdir));
 266    mash_colon_env(ld_preload_str, buf);
 267    mash_colon_env(dyld_insert_libraries_str, buf);
 268    VG_(sprintf)(buf, "%s*", VG_(libdir));
 269    mash_colon_env(ld_library_path_str, buf);
 270
 271    // Remove VALGRIND_LAUNCHER variable.
 272    VG_(env_unsetenv)(envp, VALGRIND_LAUNCHER, free_fn);
 273
 274    // Remove DYLD_SHARED_REGION variable.
 275    VG_(env_unsetenv)(envp, "DYLD_SHARED_REGION", free_fn);
 276
 277    // XXX if variable becomes empty, remove it completely?
 278
 279    VG_(free)(buf);
 280 }
 281
 282 /* Resolves filename of VG_(cl_exec_fd) and copies it to the buffer.
 283    Buffer must not be NULL and buf_size must be at least 1.
 284    If buffer is not large enough it is terminated with '\0' only
 285    when 'terminate_with_NUL == True'. */
 286 void VG_(client_fname)(HChar *buffer, SizeT buf_size, Bool terminate_with_NUL)
 287 {
 288    vg_assert(buffer != NULL);
 289    vg_assert(buf_size >= 1);
 290
 291    const HChar *name;
 292    if (VG_(resolve_filename)(VG_(cl_exec_fd), &name)) {
 293       const HChar *n = name + VG_(strlen)(name) - 1;
 294
 295       while (n > name && *n != '/')
 296          n--;
 297       if (n != name)
 298          n++;
 299
 300       VG_(strncpy)(buffer, n, buf_size);
 301       if (terminate_with_NUL)
 302          buffer[buf_size - 1] = '\0';
 303    } else {
 304       buffer[0] = '\0';
 305    }
 306 }
 307
 308 static Bool add_string(HChar *buffer, SizeT *buf_size, const HChar *string)
 309 {
 310    SizeT len = VG_(strlen)(string);
 311    VG_(strncat)(buffer, string, *buf_size);
 312    if (len >= *buf_size - 1) {
 313       *buf_size = 0;
 314       return False;
 315    } else {
 316       *buf_size -= len;
 317       return True;
 318    }
 319 }
 320
 321 /* Concatenates client exename and command line arguments into
 322    the buffer. Buffer must not be NULL and buf_size must be
 323    at least 1. Buffer is always terminated with '\0'. */
 324 void VG_(client_cmd_and_args)(HChar *buffer, SizeT buf_size)
 325 {
 326    vg_assert(buffer != NULL);
 327    vg_assert(buf_size >= 1);
 328
 329    buffer[0] = '\0';
 330
 331    if (add_string(buffer, &buf_size, VG_(args_the_exename)) == False)
 332       return;
 333
 334    Int i;
 335    for (i = 0; i < VG_(sizeXA)(VG_(args_for_client)); i++) {
 336       if (add_string(buffer, &buf_size, " ") == False)
 337          return;
 338
 339       HChar *arg = *(HChar **) VG_(indexXA)(VG_(args_for_client), i);
 340       if (add_string(buffer, &buf_size, arg) == False)
 341          return;
 342    }
 343 }
 344
 345 /* ---------------------------------------------------------------------
 346    Various important syscall wrappers
 347    ------------------------------------------------------------------ */
 348
 349 Int VG_(waitpid)(Int pid, Int *status, Int options)
 350 {
 351 #  if defined(VGO_linux)
 352    SysRes res = VG_(do_syscall4)(__NR_wait4,
 353                                  pid, (UWord)status, options, 0);
 354    return sr_isError(res) ? -1 : sr_Res(res);
 355 #  elif defined(VGO_darwin)
 356    SysRes res = VG_(do_syscall4)(__NR_wait4_nocancel,
 357                                  pid, (UWord)status, options, 0);
 358    return sr_isError(res) ? -1 : sr_Res(res);
 359 #  elif defined(VGO_solaris)
 360    SysRes res;
 361    vki_idtype_t idtype;
 362    vki_id_t id;
 363    vki_siginfo_t info;
 364
 365    /* We need to do a lot of work here. */
 366
 367    if (pid > 0) {
 368       idtype = VKI_P_PID;
 369       id = pid;
 370    }
 371    else if (pid < -1) {
 372       idtype = VKI_P_PGID;
 373       id = -pid;
 374    }
 375    else if (pid == -1) {
 376       idtype = VKI_P_ALL;
 377       id = 0;
 378    }
 379    else {
 380       idtype = VKI_P_PGID;
 381       res = VG_(do_syscall0)(__NR_getpid);
 382       id = sr_ResHI(res);
 383    }
 384
 385    options |= VKI_WEXITED | VKI_WTRAPPED;
 386
 387    res = VG_(do_syscall4)(__NR_waitsys, idtype, id, (UWord)&info, options);
 388    if (sr_isError(res))
 389       return -1;
 390
 391    if (status) {
 392       Int s = info.si_status & 0xff;
 393
 394       switch (info.si_code) {
 395          case VKI_CLD_EXITED:
 396             s <<= 8;
 397             break;
 398          case VKI_CLD_DUMPED:
 399             s |= VKI_WCOREFLG;
 400             break;
 401          case VKI_CLD_KILLED:
 402             break;
 403          case VKI_CLD_TRAPPED:
 404          case VKI_CLD_STOPPED:
 405             s <<= 8;
 406             s |= VKI_WSTOPFLG;
 407             break;
 408          case VKI_CLD_CONTINUED:
 409             s = VKI_WCONTFLG;
 410             break;
 411       }
 412       *status = s;
 413    }
 414
 415    return info.si_pid;
 416 #  else
 417 #    error Unknown OS
 418 #  endif
 419 }
 420
 421 /* clone the environment */
 422 HChar **VG_(env_clone) ( HChar **oldenv )
 423 {
 424    HChar **oldenvp;
 425    HChar **newenvp;
 426    HChar **newenv;
 427    Int  envlen;
 428
 429    vg_assert(oldenv);
 430    for (oldenvp = oldenv; oldenvp && *oldenvp; oldenvp++);
 431
 432    envlen = oldenvp - oldenv + 1;
 433
 434    newenv = VG_(malloc)("libcproc.ec.1", envlen * sizeof(HChar *));
 435
 436    oldenvp = oldenv;
 437    newenvp = newenv;
 438
 439    while (oldenvp && *oldenvp) {
 440       *newenvp++ = *oldenvp++;
 441    }
 442
 443    *newenvp = *oldenvp;
 444
 445    return newenv;
 446 }
 447
 448 void VG_(execv) ( const HChar* filename, const HChar** argv )
 449 {
 450    HChar** envp;
 451    SysRes res;
 452
 453    envp = VG_(env_clone)(VG_(client_envp));
 454    VG_(env_remove_valgrind_env_stuff)( envp, True /*ro_strings*/, NULL );
 455
 456    res = VG_(do_syscall3)(__NR_execve,
 457                           (UWord)filename, (UWord)argv, (UWord)envp);
 458
 459    VG_(printf)("EXEC failed, errno = %lld\n", (Long)sr_Err(res));
 460 }
 461
 462 /* Spawns a new child. Uses either spawn syscall or fork+execv combo. */
 463 Int VG_(spawn) ( const HChar *filename, const HChar **argv )
 464 {
 465    vg_assert(filename != NULL);
 466    vg_assert(argv != NULL);
 467
 468 #  if defined(VGO_solaris) && defined(SOLARIS_SPAWN_SYSCALL)
 469    HChar **envp = VG_(env_clone)(VG_(client_envp));
 470    for (HChar **p = envp; *p != NULL; p++) {
 471       *p = VG_(strdup)("libcproc.s.1", *p);
 472    }
 473    VG_(env_remove_valgrind_env_stuff)(envp, /* ro_strings */ False, VG_(free));
 474
 475    /* Now combine argv and argp into argenv. */
 476    SizeT argenv_size = 1 + 1;
 477    for (const HChar **p = argv; *p != NULL; p++) {
 478       argenv_size += VG_(strlen)(*p) + 2;
 479    }
 480    for (HChar **p = envp; *p != NULL; p++) {
 481       argenv_size += VG_(strlen)(*p) + 2;
 482    }
 483
 484    HChar *argenv = VG_(malloc)("libcproc.s.2", argenv_size);
 485    HChar *current = argenv;
 486 #  define COPY_CHAR_TO_ARGENV(dst, character)  \
 487       do {                                     \
 488          *(dst) = character;                   \
 489          (dst) += 1;                           \
 490       } while (0)
 491 #  define COPY_STRING_TO_ARGENV(dst, src)        \
 492       do {                                       \
 493          COPY_CHAR_TO_ARGENV(dst, '\1');         \
 494          SizeT src_len = VG_(strlen)((src)) + 1; \
 495          VG_(memcpy)((dst), (src), src_len);     \
 496          (dst) += src_len;                       \
 497       } while (0)
 498
 499    for (const HChar **p = argv; *p != NULL; p++) {
 500       COPY_STRING_TO_ARGENV(current, *p);
 501    }
 502    COPY_CHAR_TO_ARGENV(current, '\0');
 503    for (HChar **p = envp; *p != NULL; p++) {
 504       COPY_STRING_TO_ARGENV(current, *p);
 505    }
 506    COPY_CHAR_TO_ARGENV(current, '\0');
 507    vg_assert(current == argenv + argenv_size);
 508 #  undef COPY_CHAR_TO_ARGENV
 509 #  undef COPY_STRING_TOARGENV
 510
 511    SysRes res = VG_(do_syscall5)(__NR_spawn, (UWord) filename, (UWord) NULL, 0,
 512                                  (UWord) argenv, argenv_size);
 513
 514    VG_(free)(argenv);
 515    for (HChar **p = envp; *p != NULL; p++) {
 516       VG_(free)(*p);
 517    }
 518    VG_(free)(envp);
 519
 520    if (sr_isError(res))
 521       return -1;
 522    return sr_Res(res);
 523
 524 #  else
 525
 526    Int pid = VG_(fork)();
 527    if (pid < 0)
 528       return -1;
 529    if (pid == 0) {
 530       /* child */
 531       VG_(execv)(argv[0], argv);
 532
 533       /* If we're still alive here, execv failed. */
 534       VG_(exit)(1);
 535    } else {
 536       return pid;
 537    }
 538 #  endif /* VGO_solaris && SOLARIS_SPAWN_SYSCALL */
 539 }
 540
 541 /* Return -1 if error, else 0.  NOTE does not indicate return code of
 542    child! */
 543 Int VG_(system) ( const HChar* cmd )
 544 {
 545    Int pid;
 546    if (cmd == NULL)
 547       return 1;
 548
 549    const HChar *argv[4] = { "/bin/sh", "-c", cmd, 0 };
 550    pid = VG_(spawn)(argv[0], argv);
 551    if (pid < 0)
 552       return -1;
 553
 554    vg_assert(pid > 0);
 555    /* parent */
 556    /* We have to set SIGCHLD to its default behaviour in order that
 557       VG_(waitpid) works (at least on AIX).  According to the Linux
 558       man page for waitpid:
 559
 560       POSIX.1-2001 specifies that if the disposition of SIGCHLD is
 561       set to SIG_IGN or the SA_NOCLDWAIT flag is set for SIGCHLD
 562       (see sigaction(2)), then children that terminate do not
 563       become zombies and a call to wait() or waitpid() will block
 564       until all children have terminated, and then fail with errno
 565       set to ECHILD.  (The original POSIX standard left the
 566       behaviour of setting SIGCHLD to SIG_IGN unspecified.)
 567    */
 568    Int ir, zzz;
 569    vki_sigaction_toK_t sa, sa2;
 570    vki_sigaction_fromK_t saved_sa;
 571    VG_(memset)( &sa, 0, sizeof(sa) );
 572    VG_(sigemptyset)(&sa.sa_mask);
 573    sa.ksa_handler = VKI_SIG_DFL;
 574    sa.sa_flags    = 0;
 575    ir = VG_(sigaction)(VKI_SIGCHLD, &sa, &saved_sa);
 576    vg_assert(ir == 0);
 577
 578    zzz = VG_(waitpid)(pid, NULL, 0);
 579
 580    VG_(convert_sigaction_fromK_to_toK)( &saved_sa, &sa2 );
 581    ir = VG_(sigaction)(VKI_SIGCHLD, &sa2, NULL);
 582    vg_assert(ir == 0);
 583    return zzz == -1 ? -1 : 0;
 584 }
 585
 586 Int VG_(sysctl)(Int *name, UInt namelen, void *oldp, SizeT *oldlenp, void *newp, SizeT newlen)
 587 {
 588    SysRes res;
 589 #  if defined(VGO_darwin)
 590    res = VG_(do_syscall6)(__NR___sysctl,
 591                            (UWord)name, namelen, (UWord)oldp, (UWord)oldlenp, (UWord)newp, newlen);
 592 #  else
 593    res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 594 #  endif
 595    return sr_isError(res) ? -1 : sr_Res(res);
 596 }
 597
 598 /* ---------------------------------------------------------------------
 599    Resource limits
 600    ------------------------------------------------------------------ */
 601
 602 /* Support for getrlimit. */
 603 Int VG_(getrlimit) (Int resource, struct vki_rlimit *rlim)
 604 {
 605    SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 606    /* res = getrlimit( resource, rlim ); */
 607 #  ifdef __NR_ugetrlimit
 608    res = VG_(do_syscall2)(__NR_ugetrlimit, resource, (UWord)rlim);
 609 #  endif
 610    if (sr_isError(res) && sr_Err(res) == VKI_ENOSYS)
 611       res = VG_(do_syscall2)(__NR_getrlimit, resource, (UWord)rlim);
 612    return sr_isError(res) ? -1 : sr_Res(res);
 613 }
 614
 615
 616 /* Support for setrlimit. */
 617 Int VG_(setrlimit) (Int resource, const struct vki_rlimit *rlim)
 618 {
 619    SysRes res;
 620    /* res = setrlimit( resource, rlim ); */
 621    res = VG_(do_syscall2)(__NR_setrlimit, resource, (UWord)rlim);
 622    return sr_isError(res) ? -1 : sr_Res(res);
 623 }
 624
 625 /* Support for prctl. */
 626 Int VG_(prctl) (Int option,
 627                 ULong arg2, ULong arg3, ULong arg4, ULong arg5)
 628 {
 629    SysRes res = VG_(mk_SysRes_Error)(VKI_ENOSYS);
 630 #  if defined(VGO_linux)
 631    /* res = prctl( option, arg2, arg3, arg4, arg5 ); */
 632    res = VG_(do_syscall5)(__NR_prctl, (UWord) option,
 633                           (UWord) arg2, (UWord) arg3, (UWord) arg4,
 634                           (UWord) arg5);
 635 #  endif
 636
 637    return sr_isError(res) ? -1 : sr_Res(res);
 638 }
 639
 640 /* ---------------------------------------------------------------------
 641    pids, etc
 642    ------------------------------------------------------------------ */
 643
 644 Int VG_(gettid)(void)
 645 {
 646 #  if defined(VGO_linux)
 647    SysRes res = VG_(do_syscall0)(__NR_gettid);
 648
 649    if (sr_isError(res) && sr_Res(res) == VKI_ENOSYS) {
 650       HChar pid[16];
 651       /*
 652        * The gettid system call does not exist. The obvious assumption
 653        * to make at this point would be that we are running on an older
 654        * system where the getpid system call actually returns the ID of
 655        * the current thread.
 656        *
 657        * Unfortunately it seems that there are some systems with a kernel
 658        * where getpid has been changed to return the ID of the thread group
 659        * leader but where the gettid system call has not yet been added.
 660        *
 661        * So instead of calling getpid here we use readlink to see where
 662        * the /proc/self link is pointing...
 663        */
 664
 665 #     if defined(VGP_arm64_linux)
 666       res = VG_(do_syscall4)(__NR_readlinkat, VKI_AT_FDCWD,
 667                              (UWord)"/proc/self",
 668                              (UWord)pid, sizeof(pid));
 669 #     else
 670       res = VG_(do_syscall3)(__NR_readlink, (UWord)"/proc/self",
 671                              (UWord)pid, sizeof(pid));
 672 #     endif
 673       if (!sr_isError(res) && sr_Res(res) > 0) {
 674          HChar* s;
 675          pid[sr_Res(res)] = '\0';
 676          res = VG_(mk_SysRes_Success)(  VG_(strtoll10)(pid, &s) );
 677          if (*s != '\0') {
 678             VG_(message)(Vg_DebugMsg,
 679                "Warning: invalid file name linked to by /proc/self: %s\n",
 680                pid);
 681          }
 682       }
 683    }
 684
 685    return sr_Res(res);
 686
 687 #  elif defined(VGO_darwin)
 688    // Darwin's gettid syscall is something else.
 689    // Use Mach thread ports for lwpid instead.
 690    return mach_thread_self();
 691
 692 #  elif defined(VGO_solaris)
 693    SysRes res = VG_(do_syscall0)(__NR_lwp_self);
 694    return sr_Res(res);
 695
 696 #  else
 697 #    error "Unknown OS"
 698 #  endif
 699 }
 700
 701 /* You'd be amazed how many places need to know the current pid. */
 702 Int VG_(getpid) ( void )
 703 {
 704    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 705    return sr_Res( VG_(do_syscall0)(__NR_getpid) );
 706 }
 707
 708 Int VG_(getpgrp) ( void )
 709 {
 710    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 711 #  if defined(VGP_arm64_linux)
 712    return sr_Res( VG_(do_syscall1)(__NR_getpgid, 0) );
 713 #  elif defined(VGO_linux) || defined(VGO_darwin)
 714    return sr_Res( VG_(do_syscall0)(__NR_getpgrp) );
 715 #  elif defined(VGO_solaris)
 716    /* Uses the shared pgrpsys syscall, 0 for the getpgrp variant. */
 717    return sr_Res( VG_(do_syscall1)(__NR_pgrpsys, 0) );
 718 #  else
 719 #    error Unknown OS
 720 #  endif
 721 }
 722
 723 Int VG_(getppid) ( void )
 724 {
 725    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 726 #  if defined(VGO_linux) || defined(VGO_darwin)
 727    return sr_Res( VG_(do_syscall0)(__NR_getppid) );
 728 #  elif defined(VGO_solaris)
 729    /* Uses the shared getpid/getppid syscall, val2 contains a parent pid. */
 730    return sr_ResHI( VG_(do_syscall0)(__NR_getpid) );
 731 #  else
 732 #    error Unknown OS
 733 #  endif
 734 }
 735
 736 Int VG_(geteuid) ( void )
 737 {
 738    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 739 #  if defined(VGO_linux) || defined(VGO_darwin)
 740    {
 741 #     if defined(__NR_geteuid32)
 742       // We use the 32-bit version if it's supported.  Otherwise, IDs greater
 743       // than 65536 cause problems, as bug #151209 showed.
 744       return sr_Res( VG_(do_syscall0)(__NR_geteuid32) );
 745 #     else
 746       return sr_Res( VG_(do_syscall0)(__NR_geteuid) );
 747 #     endif
 748    }
 749 #  elif defined(VGO_solaris)
 750    /* Uses the shared getuid/geteuid syscall, val2 contains the effective
 751       uid. */
 752    return sr_ResHI( VG_(do_syscall0)(__NR_getuid) );
 753 #  else
 754 #    error Unknown OS
 755 #  endif
 756 }
 757
 758 Int VG_(getegid) ( void )
 759 {
 760 #  if defined(VGO_linux) || defined(VGO_darwin)
 761    /* ASSUMES SYSCALL ALWAYS SUCCEEDS */
 762 #    if defined(__NR_getegid32)
 763    // We use the 32-bit version if it's supported.  Otherwise, IDs greater
 764    // than 65536 cause problems, as bug #151209 showed.
 765    return sr_Res( VG_(do_syscall0)(__NR_getegid32) );
 766 #    else
 767    return sr_Res( VG_(do_syscall0)(__NR_getegid) );
 768 #    endif
 769
 770 #  elif defined(VGO_solaris)
 771    /* Uses the shared getgid/getegid syscall, val2 contains the effective
 772       gid. */
 773    return sr_ResHI( VG_(do_syscall0)(__NR_getgid) );
 774 #  else
 775 #    error Unknown OS
 776 #  endif
 777 }
 778
 779 /* Get supplementary groups into list[0 .. size-1].  Returns the
 780    number of groups written, or -1 if error.  Note that in order to be
 781    portable, the groups are 32-bit unsigned ints regardless of the
 782    platform.
 783    As a special case, if size == 0 the function returns the number of
 784    groups leaving list untouched. */
 785 Int VG_(getgroups)( Int size, UInt* list )
 786 {
 787    if (size < 0) return -1;
 788
 789 #  if defined(VGP_x86_linux) || defined(VGP_ppc32_linux) \
 790       || defined(VGP_mips64_linux)
 791    Int    i;
 792    SysRes sres;
 793    UShort list16[size];
 794    sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list16);
 795    if (sr_isError(sres))
 796       return -1;
 797    if (size != 0) {
 798       for (i = 0; i < sr_Res(sres); i++)
 799          list[i] = (UInt)list16[i];
 800    }
 801    return sr_Res(sres);
 802
 803 #  elif defined(VGP_amd64_linux) || defined(VGP_arm_linux) \
 804         || defined(VGP_ppc64be_linux) || defined(VGP_ppc64le_linux)  \
 805         || defined(VGO_darwin) || defined(VGP_s390x_linux)    \
 806         || defined(VGP_mips32_linux) || defined(VGP_arm64_linux) \
 807         || defined(VGO_solaris)
 808    SysRes sres;
 809    sres = VG_(do_syscall2)(__NR_getgroups, size, (Addr)list);
 810    if (sr_isError(sres))
 811       return -1;
 812    return sr_Res(sres);
 813
 814 #  else
 815 #     error "VG_(getgroups): needs implementation on this platform"
 816 #  endif
 817 }
 818
 819 /* ---------------------------------------------------------------------
 820    Process tracing
 821    ------------------------------------------------------------------ */
 822
 823 Int VG_(ptrace) ( Int request, Int pid, void *addr, void *data )
 824 {
 825    SysRes res;
 826 #  if defined(VGO_linux) || defined(VGO_darwin)
 827    res = VG_(do_syscall4)(__NR_ptrace, request, pid, (UWord)addr, (UWord)data);
 828 #  elif defined(VGO_solaris)
 829    /* There is no ptrace syscall on Solaris.  Such requests has to be
 830       implemented using the /proc interface.  Callers of VG_(ptrace) should
 831       ensure that this function is not reached on Solaris, i.e. they must
 832       provide a special code for Solaris for whatever feature they provide. */
 833    I_die_here;
 834 #  else
 835 #    error Unknown OS
 836 #  endif
 837    if (sr_isError(res))
 838       return -1;
 839    return sr_Res(res);
 840 }
 841
 842 /* ---------------------------------------------------------------------
 843    Fork
 844    ------------------------------------------------------------------ */
 845
 846 Int VG_(fork) ( void )
 847 {
 848 #  if defined(VGP_arm64_linux)
 849    SysRes res;
 850    res = VG_(do_syscall5)(__NR_clone, VKI_SIGCHLD,
 851                           (UWord)NULL, (UWord)NULL, (UWord)NULL, (UWord)NULL);
 852    if (sr_isError(res))
 853       return -1;
 854    return sr_Res(res);
 855
 856 #  elif defined(VGO_linux)
 857    SysRes res;
 858    res = VG_(do_syscall0)(__NR_fork);
 859    if (sr_isError(res))
 860       return -1;
 861    return sr_Res(res);
 862
 863 #  elif defined(VGO_darwin)
 864    SysRes res;
 865    res = VG_(do_syscall0)(__NR_fork); /* __NR_fork is UX64 */
 866    if (sr_isError(res))
 867       return -1;
 868    /* on success: wLO = child pid; wHI = 1 for child, 0 for parent */
 869    if (sr_ResHI(res) != 0) {
 870       return 0;  /* this is child: return 0 instead of child pid */
 871    }
 872    return sr_Res(res);
 873
 874 #  elif defined(VGO_solaris)
 875    /* Using fork() on Solaris is not really the best thing to do. Solaris
 876       does not do memory overcommitment so fork() can fail if there is not
 877       enough memory to copy the current process into a new one.
 878       Prefer to use VG_(spawn)() over VG_(fork)() + VG_(execv)(). */
 879    SysRes res;
 880    res = VG_(do_syscall2)(__NR_forksys, 0 /*subcode (fork)*/, 0 /*flags*/);
 881    if (sr_isError(res))
 882       return -1;
 883    /* On success:
 884         val = a pid of the child in the parent, a pid of the parent in the
 885               child,
 886         val2 = 0 in the parent process, 1 in the child process. */
 887    if (sr_ResHI(res) != 0) {
 888       return 0;
 889    }
 890    return sr_Res(res);
 891
 892 #  else
 893 #    error "Unknown OS"
 894 #  endif
 895 }
 896
 897 /* ---------------------------------------------------------------------
 898    Timing stuff
 899    ------------------------------------------------------------------ */
 900
 901 UInt VG_(read_millisecond_timer) ( void )
 902 {
 903    /* 'now' and 'base' are in microseconds */
 904    static ULong base = 0;
 905    ULong  now;
 906
 907 #  if defined(VGO_linux) || defined(VGO_solaris)
 908    { SysRes res;
 909      struct vki_timespec ts_now;
 910      res = VG_(do_syscall2)(__NR_clock_gettime, VKI_CLOCK_MONOTONIC,
 911                             (UWord)&ts_now);
 912      if (sr_isError(res) == 0) {
 913         now = ts_now.tv_sec * 1000000ULL + ts_now.tv_nsec / 1000;
 914      } else {
 915        struct vki_timeval tv_now;
 916        /* Note: On Solaris, this syscall takes only one parameter but the
 917           extra dummy one does not cause any harm. */
 918        res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
 919        vg_assert(! sr_isError(res));
 920        now = tv_now.tv_sec * 1000000ULL + tv_now.tv_usec;
 921      }
 922    }
 923
 924 #  elif defined(VGO_darwin)
 925    // Weird: it seems that gettimeofday() doesn't fill in the timeval, but
 926    // rather returns the tv_sec as the low 32 bits of the result and the
 927    // tv_usec as the high 32 bits of the result.  (But the timeval cannot be
 928    // NULL!)  See bug 200990.
 929    { SysRes res;
 930      struct vki_timeval tv_now = { 0, 0 };
 931      res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)&tv_now, (UWord)NULL);
 932      vg_assert(! sr_isError(res));
 933      now = sr_Res(res) * 1000000ULL + sr_ResHI(res);
 934    }
 935
 936 #  else
 937 #    error "Unknown OS"
 938 #  endif
 939
 940    /* COMMON CODE */
 941    if (base == 0)
 942       base = now;
 943
 944    return (now - base) / 1000;
 945 }
 946
 947 Int VG_(gettimeofday)(struct vki_timeval *tv, struct vki_timezone *tz)
 948 {
 949    SysRes res;
 950    res = VG_(do_syscall2)(__NR_gettimeofday, (UWord)tv, (UWord)tz);
 951
 952    if (! sr_isError(res)) return 0;
 953
 954    /* Make sure, argument values are deterministic upon failure */
 955    if (tv) *tv = (struct vki_timeval){ .tv_sec = 0, .tv_usec = 0 };
 956    if (tz) *tz = (struct vki_timezone){ .tz_minuteswest = 0, .tz_dsttime = 0 };
 957
 958    return -1;
 959 }
 960
 961 UInt VG_(get_user_milliseconds)(void)
 962 {
 963    UInt res = 0;
 964 #  if defined(VGO_linux)
 965    {
 966       struct vki_rusage ru;
 967       VG_(memset)(&ru, 0, sizeof(ru));
 968       SysRes sr = VG_(do_syscall2)(__NR_getrusage, VKI_RUSAGE_SELF, (UWord)&ru);
 969       if (!sr_isError(sr)) {
 970          res = ru.ru_utime.tv_sec * 1000 + ru.ru_utime.tv_usec / 1000;
 971       }
 972    }
 973
 974 #  elif defined(VGO_solaris)
 975    {
 976       struct vki_rusage ru;
 977       VG_(memset)(&ru, 0, sizeof(ru));
 978       SysRes sr = VG_(do_syscall2)(__NR_rusagesys, VKI__RUSAGESYS_GETRUSAGE,
 979                                    (UWord) &ru);
 980       if (!sr_isError(sr)) {
 981          res = ru.ru_utime.tv_sec * 1000 + ru.ru_utime.tv_usec / 1000;
 982       }
 983    }
 984
 985 #  elif defined(VGO_darwin)
 986    res = 0;
 987
 988 #  else
 989 #    error "Unknown OS"
 990 #  endif
 991
 992    return res;
 993 }
 994
 995
 996 /* ---------------------------------------------------------------------
 997    atfork()
 998    ------------------------------------------------------------------ */
 999
1000 struct atfork {
1001    vg_atfork_t  pre;
1002    vg_atfork_t  parent;
1003    vg_atfork_t  child;
1004 };
1005
1006 #define VG_MAX_ATFORK 10
1007
1008 static struct atfork atforks[VG_MAX_ATFORK];
1009 static Int n_atfork = 0;
1010
1011 void VG_(atfork)(vg_atfork_t pre, vg_atfork_t parent, vg_atfork_t child)
1012 {
1013    Int i;
1014
1015    for (i = 0; i < n_atfork; i++) {
1016       if (atforks[i].pre == pre &&
1017           atforks[i].parent == parent &&
1018           atforks[i].child == child)
1019          return;
1020    }
1021
1022    if (n_atfork >= VG_MAX_ATFORK)
1023       VG_(core_panic)(
1024          "Too many VG_(atfork) handlers requested: raise VG_MAX_ATFORK");
1025
1026    atforks[n_atfork].pre    = pre;
1027    atforks[n_atfork].parent = parent;
1028    atforks[n_atfork].child  = child;
1029
1030    n_atfork++;
1031 }
1032
1033 void VG_(do_atfork_pre)(ThreadId tid)
1034 {
1035    Int i;
1036
1037    for (i = 0; i < n_atfork; i++)
1038       if (atforks[i].pre != NULL)
1039          (*atforks[i].pre)(tid);
1040 }
1041
1042 void VG_(do_atfork_parent)(ThreadId tid)
1043 {
1044    Int i;
1045
1046    for (i = 0; i < n_atfork; i++)
1047       if (atforks[i].parent != NULL)
1048          (*atforks[i].parent)(tid);
1049 }
1050
1051 void VG_(do_atfork_child)(ThreadId tid)
1052 {
1053    Int i;
1054
1055    for (i = 0; i < n_atfork; i++)
1056       if (atforks[i].child != NULL)
1057          (*atforks[i].child)(tid);
1058 }
1059
1060
1061 /* ---------------------------------------------------------------------
1062    icache invalidation
1063    ------------------------------------------------------------------ */
1064
1065 void VG_(invalidate_icache) ( void *ptr, SizeT nbytes )
1066 {
1067    if (nbytes == 0) return;    // nothing to do
1068
1069    // Get cache info
1070    VexArchInfo vai;
1071    VG_(machine_get_VexArchInfo)(NULL, &vai);
1072
1073    // If I-caches are coherent, nothing needs to be done here
1074    if (vai.hwcache_info.icaches_maintain_coherence) return;
1075
1076 #  if defined(VGA_ppc32) || defined(VGA_ppc64be) || defined(VGA_ppc64le)
1077    Addr startaddr = (Addr) ptr;
1078    Addr endaddr   = startaddr + nbytes;
1079    Addr cls;
1080    Addr addr;
1081
1082    cls = vai.ppc_icache_line_szB;
1083
1084    /* Stay sane .. */
1085    vg_assert(cls == 16 || cls == 32 || cls == 64 || cls == 128);
1086
1087    startaddr &= ~(cls - 1);
1088    for (addr = startaddr; addr < endaddr; addr += cls) {
1089       __asm__ __volatile__("dcbst 0,%0" : : "r" (addr));
1090    }
1091    __asm__ __volatile__("sync");
1092    for (addr = startaddr; addr < endaddr; addr += cls) {
1093       __asm__ __volatile__("icbi 0,%0" : : "r" (addr));
1094    }
1095    __asm__ __volatile__("sync; isync");
1096
1097 #  elif defined(VGP_arm_linux)
1098    /* ARM cache flushes are privileged, so we must defer to the kernel. */
1099    Addr startaddr = (Addr) ptr;
1100    Addr endaddr   = startaddr + nbytes;
1101    VG_(do_syscall2)(__NR_ARM_cacheflush, startaddr, endaddr);
1102
1103 #  elif defined(VGP_arm64_linux)
1104    // This arm64_linux section of this function VG_(invalidate_icache)
1105    // is copied from
1106    // https://github.com/armvixl/vixl/blob/master/src/a64/cpu-a64.cc
1107    // which has the following copyright notice:
1108    /*
1109    Copyright 2013, ARM Limited
1110    All rights reserved.
1111
1112    Redistribution and use in source and binary forms, with or without
1113    modification, are permitted provided that the following conditions are met:
1114
1115    * Redistributions of source code must retain the above copyright notice,
1116      this list of conditions and the following disclaimer.
1117    * Redistributions in binary form must reproduce the above copyright notice,
1118      this list of conditions and the following disclaimer in the documentation
1119      and/or other materials provided with the distribution.
1120    * Neither the name of ARM Limited nor the names of its contributors may be
1121      used to endorse or promote products derived from this software without
1122      specific prior written permission.
1123
1124    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
1125    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
1126    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
1127    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
1128    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1129    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
1130    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
1131    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
1132    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1133    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1134    */
1135
1136    // Ask what the I and D line sizes are
1137    UInt cache_type_register;
1138    // Copy the content of the cache type register to a core register.
1139    __asm__ __volatile__ ("mrs %[ctr], ctr_el0" // NOLINT
1140                          : [ctr] "=r" (cache_type_register));
1141
1142    const Int kDCacheLineSizeShift = 16;
1143    const Int kICacheLineSizeShift = 0;
1144    const UInt kDCacheLineSizeMask = 0xf << kDCacheLineSizeShift;
1145    const UInt kICacheLineSizeMask = 0xf << kICacheLineSizeShift;
1146
1147    // The cache type register holds the size of the I and D caches as a power of
1148    // two.
1149    const UInt dcache_line_size_power_of_two =
1150        (cache_type_register & kDCacheLineSizeMask) >> kDCacheLineSizeShift;
1151    const UInt icache_line_size_power_of_two =
1152        (cache_type_register & kICacheLineSizeMask) >> kICacheLineSizeShift;
1153
1154    const UInt dcache_line_size_ = 4 * (1 << dcache_line_size_power_of_two);
1155    const UInt icache_line_size_ = 4 * (1 << icache_line_size_power_of_two);
1156
1157    Addr start = (Addr)ptr;
1158    // Sizes will be used to generate a mask big enough to cover a pointer.
1159    Addr dsize = (Addr)dcache_line_size_;
1160    Addr isize = (Addr)icache_line_size_;
1161
1162    // Cache line sizes are always a power of 2.
1163    Addr dstart = start & ~(dsize - 1);
1164    Addr istart = start & ~(isize - 1);
1165    Addr end    = start + nbytes;
1166
1167    __asm__ __volatile__ (
1168      // Clean every line of the D cache containing the target data.
1169      "0: \n\t"
1170      // dc : Data Cache maintenance
1171      // c : Clean
1172      // va : by (Virtual) Address
1173      // u : to the point of Unification
1174      // The point of unification for a processor is the point by which the
1175      // instruction and data caches are guaranteed to see the same copy of a
1176      // memory location. See ARM DDI 0406B page B2-12 for more information.
1177      "dc cvau, %[dline] \n\t"
1178      "add %[dline], %[dline], %[dsize] \n\t"
1179      "cmp %[dline], %[end] \n\t"
1180      "b.lt 0b \n\t"
1181      // Barrier to make sure the effect of the code above is visible to the rest
1182      // of the world.
1183      // dsb : Data Synchronisation Barrier
1184      // ish : Inner SHareable domain
1185      // The point of unification for an Inner Shareable shareability domain is
1186      // the point by which the instruction and data caches of all the processors
1187      // in that Inner Shareable shareability domain are guaranteed to see the
1188      // same copy of a memory location. See ARM DDI 0406B page B2-12 for more
1189      // information.
1190      "dsb ish \n\t"
1191      // Invalidate every line of the I cache containing the target data.
1192      "1: \n\t"
1193      // ic : instruction cache maintenance
1194      // i : invalidate
1195      // va : by address
1196      // u : to the point of unification
1197      "ic ivau, %[iline] \n\t"
1198      "add %[iline], %[iline], %[isize] \n\t"
1199      "cmp %[iline], %[end] \n\t"
1200      "b.lt 1b \n\t"
1201      // Barrier to make sure the effect of the code above is visible to the rest
1202      // of the world.
1203      "dsb ish \n\t"
1204      // Barrier to ensure any prefetching which happened before this code is
1205      // discarded.
1206      // isb : Instruction Synchronisation Barrier
1207      "isb \n\t"
1208      : [dline] "+r" (dstart),
1209        [iline] "+r" (istart)
1210      : [dsize] "r" (dsize),
1211        [isize] "r" (isize),
1212        [end] "r" (end)
1213      // This code does not write to memory but without the dependency gcc might
1214      // move this code before the code is generated.
1215      : "cc", "memory"
1216    );
1217
1218 #  elif defined(VGA_mips32) || defined(VGA_mips64)
1219    SysRes sres = VG_(do_syscall3)(__NR_cacheflush, (UWord) ptr,
1220                                  (UWord) nbytes, (UWord) 3);
1221    vg_assert( !sr_isError(sres) );
1222
1223 #  endif
1224 }
1225
1226
1227 /* ---------------------------------------------------------------------
1228    dcache flushing
1229    ------------------------------------------------------------------ */
1230
1231 void VG_(flush_dcache) ( void *ptr, SizeT nbytes )
1232 {
1233    /* Currently this is only required on ARM64. */
1234 #  if defined(VGA_arm64)
1235    Addr startaddr = (Addr) ptr;
1236    Addr endaddr   = startaddr + nbytes;
1237    Addr cls;
1238    Addr addr;
1239
1240    ULong ctr_el0;
1241    __asm__ __volatile__ ("mrs %0, ctr_el0" : "=r"(ctr_el0));
1242    cls = 4 * (1ULL << (0xF & (ctr_el0 >> 16)));
1243
1244    /* Stay sane .. */
1245    vg_assert(cls == 64 || cls == 128);
1246
1247    startaddr &= ~(cls - 1);
1248    for (addr = startaddr; addr < endaddr; addr += cls) {
1249       __asm__ __volatile__("dc cvau, %0" : : "r" (addr));
1250    }
1251    __asm__ __volatile__("dsb ish");
1252 #  endif
1253 }
1254
1255 /*--------------------------------------------------------------------*/
1256 /*--- end                                                          ---*/
1257 /*--------------------------------------------------------------------*/