1 /*
   2  * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 // According to the AIX OS doc #pragma alloca must be used
  27 // with C++ compiler before referencing the function alloca()
  28 #pragma alloca
  29 
  30 // no precompiled headers
  31 #include "jvm.h"
  32 #include "classfile/classLoader.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "code/icBuffer.hpp"
  36 #include "code/vtableStubs.hpp"
  37 #include "compiler/compileBroker.hpp"
  38 #include "interpreter/interpreter.hpp"
  39 #include "logging/log.hpp"
  40 #include "libo4.hpp"
  41 #include "libperfstat_aix.hpp"
  42 #include "libodm_aix.hpp"
  43 #include "loadlib_aix.hpp"
  44 #include "memory/allocation.inline.hpp"
  45 #include "memory/filemap.hpp"
  46 #include "misc_aix.hpp"
  47 #include "oops/oop.inline.hpp"
  48 #include "os_aix.inline.hpp"
  49 #include "os_share_aix.hpp"
  50 #include "porting_aix.hpp"
  51 #include "prims/jniFastGetField.hpp"
  52 #include "prims/jvm_misc.hpp"
  53 #include "runtime/arguments.hpp"
  54 #include "runtime/atomic.hpp"
  55 #include "runtime/extendedPC.hpp"
  56 #include "runtime/globals.hpp"
  57 #include "runtime/interfaceSupport.hpp"
  58 #include "runtime/java.hpp"
  59 #include "runtime/javaCalls.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/objectMonitor.hpp"
  62 #include "runtime/orderAccess.inline.hpp"
  63 #include "runtime/os.hpp"
  64 #include "runtime/osThread.hpp"
  65 #include "runtime/perfMemory.hpp"
  66 #include "runtime/sharedRuntime.hpp"
  67 #include "runtime/statSampler.hpp"
  68 #include "runtime/stubRoutines.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "runtime/threadCritical.hpp"
  71 #include "runtime/timer.hpp"
  72 #include "runtime/vm_version.hpp"
  73 #include "services/attachListener.hpp"
  74 #include "services/runtimeService.hpp"
  75 #include "utilities/align.hpp"
  76 #include "utilities/decoder.hpp"
  77 #include "utilities/defaultStream.hpp"
  78 #include "utilities/events.hpp"
  79 #include "utilities/growableArray.hpp"
  80 #include "utilities/vmError.hpp"
  81 
  82 // put OS-includes here (sorted alphabetically)
  83 #include <errno.h>
  84 #include <fcntl.h>
  85 #include <inttypes.h>
  86 #include <poll.h>
  87 #include <procinfo.h>
  88 #include <pthread.h>
  89 #include <pwd.h>
  90 #include <semaphore.h>
  91 #include <signal.h>
  92 #include <stdint.h>
  93 #include <stdio.h>
  94 #include <string.h>
  95 #include <unistd.h>
  96 #include <sys/ioctl.h>
  97 #include <sys/ipc.h>
  98 #include <sys/mman.h>
  99 #include <sys/resource.h>
 100 #include <sys/select.h>
 101 #include <sys/shm.h>
 102 #include <sys/socket.h>
 103 #include <sys/stat.h>
 104 #include <sys/sysinfo.h>
 105 #include <sys/systemcfg.h>
 106 #include <sys/time.h>
 107 #include <sys/times.h>
 108 #include <sys/types.h>
 109 #include <sys/utsname.h>
 110 #include <sys/vminfo.h>
 111 #include <sys/wait.h>
 112 
 113 // Missing prototypes for various system APIs.
 114 extern "C"
 115 int mread_real_time(timebasestruct_t *t, size_t size_of_timebasestruct_t);
 116 
 117 #if !defined(_AIXVERSION_610)
 118 extern "C" int getthrds64(pid_t, struct thrdentry64*, int, tid64_t*, int);
 119 extern "C" int getprocs64(procentry64*, int, fdsinfo*, int, pid_t*, int);
 120 extern "C" int getargs(procsinfo*, int, char*, int);
 121 #endif
 122 
 123 #define MAX_PATH (2 * K)
 124 
 125 // for timer info max values which include all bits
 126 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 127 // for multipage initialization error analysis (in 'g_multipage_error')
 128 #define ERROR_MP_OS_TOO_OLD                          100
 129 #define ERROR_MP_EXTSHM_ACTIVE                       101
 130 #define ERROR_MP_VMGETINFO_FAILED                    102
 131 #define ERROR_MP_VMGETINFO_CLAIMS_NO_SUPPORT_FOR_64K 103
 132 
 133 // excerpts from systemcfg.h that might be missing on older os levels
 134 #ifndef PV_5_Compat
 135   #define PV_5_Compat 0x0F8000   /* Power PC 5 */
 136 #endif
 137 #ifndef PV_6
 138   #define PV_6 0x100000          /* Power PC 6 */
 139 #endif
 140 #ifndef PV_6_1
 141   #define PV_6_1 0x100001        /* Power PC 6 DD1.x */
 142 #endif
 143 #ifndef PV_6_Compat
 144   #define PV_6_Compat 0x108000   /* Power PC 6 */
 145 #endif
 146 #ifndef PV_7
 147   #define PV_7 0x200000          /* Power PC 7 */
 148 #endif
 149 #ifndef PV_7_Compat
 150   #define PV_7_Compat 0x208000   /* Power PC 7 */
 151 #endif
 152 #ifndef PV_8
 153   #define PV_8 0x300000          /* Power PC 8 */
 154 #endif
 155 #ifndef PV_8_Compat
 156   #define PV_8_Compat 0x308000   /* Power PC 8 */
 157 #endif
 158 
 159 static address resolve_function_descriptor_to_code_pointer(address p);
 160 
 161 static void vmembk_print_on(outputStream* os);
 162 
 163 ////////////////////////////////////////////////////////////////////////////////
 164 // global variables (for a description see os_aix.hpp)
 165 
 166 julong    os::Aix::_physical_memory = 0;
 167 
 168 pthread_t os::Aix::_main_thread = ((pthread_t)0);
 169 int       os::Aix::_page_size = -1;
 170 
 171 // -1 = uninitialized, 0 if AIX, 1 if OS/400 pase
 172 int       os::Aix::_on_pase = -1;
 173 
 174 // 0 = uninitialized, otherwise 32 bit number:
 175 //  0xVVRRTTSS
 176 //  VV - major version
 177 //  RR - minor version
 178 //  TT - tech level, if known, 0 otherwise
 179 //  SS - service pack, if known, 0 otherwise
 180 uint32_t  os::Aix::_os_version = 0;
 181 
 182 // -1 = uninitialized, 0 - no, 1 - yes
 183 int       os::Aix::_xpg_sus_mode = -1;
 184 
 185 // -1 = uninitialized, 0 - no, 1 - yes
 186 int       os::Aix::_extshm = -1;
 187 
 188 ////////////////////////////////////////////////////////////////////////////////
 189 // local variables
 190 
 191 static volatile jlong max_real_time = 0;
 192 static jlong    initial_time_count = 0;
 193 static int      clock_tics_per_sec = 100;
 194 static sigset_t check_signal_done;         // For diagnostics to print a message once (see run_periodic_checks)
 195 static bool     check_signals      = true;
 196 static int      SR_signum          = SIGUSR2; // Signal used to suspend/resume a thread (must be > SIGSEGV, see 4355769)
 197 static sigset_t SR_sigset;
 198 
 199 // Process break recorded at startup.
 200 static address g_brk_at_startup = NULL;
 201 
 202 // This describes the state of multipage support of the underlying
 203 // OS. Note that this is of no interest to the outsize world and
 204 // therefore should not be defined in AIX class.
 205 //
 206 // AIX supports four different page sizes - 4K, 64K, 16MB, 16GB. The
 207 // latter two (16M "large" resp. 16G "huge" pages) require special
 208 // setup and are normally not available.
 209 //
 210 // AIX supports multiple page sizes per process, for:
 211 //  - Stack (of the primordial thread, so not relevant for us)
 212 //  - Data - data, bss, heap, for us also pthread stacks
 213 //  - Text - text code
 214 //  - shared memory
 215 //
 216 // Default page sizes can be set via linker options (-bdatapsize, -bstacksize, ...)
 217 // and via environment variable LDR_CNTRL (DATAPSIZE, STACKPSIZE, ...).
 218 //
 219 // For shared memory, page size can be set dynamically via
 220 // shmctl(). Different shared memory regions can have different page
 221 // sizes.
 222 //
 223 // More information can be found at AIBM info center:
 224 //   http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/multiple_page_size_app_support.htm
 225 //
 226 static struct {
 227   size_t pagesize;            // sysconf _SC_PAGESIZE (4K)
 228   size_t datapsize;           // default data page size (LDR_CNTRL DATAPSIZE)
 229   size_t shmpsize;            // default shared memory page size (LDR_CNTRL SHMPSIZE)
 230   size_t pthr_stack_pagesize; // stack page size of pthread threads
 231   size_t textpsize;           // default text page size (LDR_CNTRL STACKPSIZE)
 232   bool can_use_64K_pages;     // True if we can alloc 64K pages dynamically with Sys V shm.
 233   bool can_use_16M_pages;     // True if we can alloc 16M pages dynamically with Sys V shm.
 234   int error;                  // Error describing if something went wrong at multipage init.
 235 } g_multipage_support = {
 236   (size_t) -1,
 237   (size_t) -1,
 238   (size_t) -1,
 239   (size_t) -1,
 240   (size_t) -1,
 241   false, false,
 242   0
 243 };
 244 
 245 // We must not accidentally allocate memory close to the BRK - even if
 246 // that would work - because then we prevent the BRK segment from
 247 // growing which may result in a malloc OOM even though there is
 248 // enough memory. The problem only arises if we shmat() or mmap() at
 249 // a specific wish address, e.g. to place the heap in a
 250 // compressed-oops-friendly way.
 251 static bool is_close_to_brk(address a) {
 252   assert0(g_brk_at_startup != NULL);
 253   if (a >= g_brk_at_startup &&
 254       a < (g_brk_at_startup + MaxExpectedDataSegmentSize)) {
 255     return true;
 256   }
 257   return false;
 258 }
 259 
 260 julong os::available_memory() {
 261   return Aix::available_memory();
 262 }
 263 
 264 julong os::Aix::available_memory() {
 265   // Avoid expensive API call here, as returned value will always be null.
 266   if (os::Aix::on_pase()) {
 267     return 0x0LL;
 268   }
 269   os::Aix::meminfo_t mi;
 270   if (os::Aix::get_meminfo(&mi)) {
 271     return mi.real_free;
 272   } else {
 273     return ULONG_MAX;
 274   }
 275 }
 276 
 277 julong os::physical_memory() {
 278   return Aix::physical_memory();
 279 }
 280 
 281 // Return true if user is running as root.
 282 
 283 bool os::have_special_privileges() {
 284   static bool init = false;
 285   static bool privileges = false;
 286   if (!init) {
 287     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 288     init = true;
 289   }
 290   return privileges;
 291 }
 292 
 293 // Helper function, emulates disclaim64 using multiple 32bit disclaims
 294 // because we cannot use disclaim64() on AS/400 and old AIX releases.
 295 static bool my_disclaim64(char* addr, size_t size) {
 296 
 297   if (size == 0) {
 298     return true;
 299   }
 300 
 301   // Maximum size 32bit disclaim() accepts. (Theoretically 4GB, but I just do not trust that.)
 302   const unsigned int maxDisclaimSize = 0x40000000;
 303 
 304   const unsigned int numFullDisclaimsNeeded = (size / maxDisclaimSize);
 305   const unsigned int lastDisclaimSize = (size % maxDisclaimSize);
 306 
 307   char* p = addr;
 308 
 309   for (int i = 0; i < numFullDisclaimsNeeded; i ++) {
 310     if (::disclaim(p, maxDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 311       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + maxDisclaimSize, errno);
 312       return false;
 313     }
 314     p += maxDisclaimSize;
 315   }
 316 
 317   if (lastDisclaimSize > 0) {
 318     if (::disclaim(p, lastDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 319       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + lastDisclaimSize, errno);
 320       return false;
 321     }
 322   }
 323 
 324   return true;
 325 }
 326 
 327 // Cpu architecture string
 328 #if defined(PPC32)
 329 static char cpu_arch[] = "ppc";
 330 #elif defined(PPC64)
 331 static char cpu_arch[] = "ppc64";
 332 #else
 333 #error Add appropriate cpu_arch setting
 334 #endif
 335 
 336 // Wrap the function "vmgetinfo" which is not available on older OS releases.
 337 static int checked_vmgetinfo(void *out, int command, int arg) {
 338   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 339     guarantee(false, "cannot call vmgetinfo on AS/400 older than V6R1");
 340   }
 341   return ::vmgetinfo(out, command, arg);
 342 }
 343 
 344 // Given an address, returns the size of the page backing that address.
 345 size_t os::Aix::query_pagesize(void* addr) {
 346 
 347   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 348     // AS/400 older than V6R1: no vmgetinfo here, default to 4K
 349     return 4*K;
 350   }
 351 
 352   vm_page_info pi;
 353   pi.addr = (uint64_t)addr;
 354   if (checked_vmgetinfo(&pi, VM_PAGE_INFO, sizeof(pi)) == 0) {
 355     return pi.pagesize;
 356   } else {
 357     assert(false, "vmgetinfo failed to retrieve page size");
 358     return 4*K;
 359   }
 360 }
 361 
 362 void os::Aix::initialize_system_info() {
 363 
 364   // Get the number of online(logical) cpus instead of configured.
 365   os::_processor_count = sysconf(_SC_NPROCESSORS_ONLN);
 366   assert(_processor_count > 0, "_processor_count must be > 0");
 367 
 368   // Retrieve total physical storage.
 369   os::Aix::meminfo_t mi;
 370   if (!os::Aix::get_meminfo(&mi)) {
 371     assert(false, "os::Aix::get_meminfo failed.");
 372   }
 373   _physical_memory = (julong) mi.real_total;
 374 }
 375 
 376 // Helper function for tracing page sizes.
 377 static const char* describe_pagesize(size_t pagesize) {
 378   switch (pagesize) {
 379     case 4*K : return "4K";
 380     case 64*K: return "64K";
 381     case 16*M: return "16M";
 382     case 16*G: return "16G";
 383     default:
 384       assert(false, "surprise");
 385       return "??";
 386   }
 387 }
 388 
 389 // Probe OS for multipage support.
 390 // Will fill the global g_multipage_support structure.
 391 // Must be called before calling os::large_page_init().
 392 static void query_multipage_support() {
 393 
 394   guarantee(g_multipage_support.pagesize == -1,
 395             "do not call twice");
 396 
 397   g_multipage_support.pagesize = ::sysconf(_SC_PAGESIZE);
 398 
 399   // This really would surprise me.
 400   assert(g_multipage_support.pagesize == 4*K, "surprise!");
 401 
 402   // Query default data page size (default page size for C-Heap, pthread stacks and .bss).
 403   // Default data page size is defined either by linker options (-bdatapsize)
 404   // or by environment variable LDR_CNTRL (suboption DATAPSIZE). If none is given,
 405   // default should be 4K.
 406   {
 407     void* p = ::malloc(16*M);
 408     g_multipage_support.datapsize = os::Aix::query_pagesize(p);
 409     ::free(p);
 410   }
 411 
 412   // Query default shm page size (LDR_CNTRL SHMPSIZE).
 413   // Note that this is pure curiosity. We do not rely on default page size but set
 414   // our own page size after allocated.
 415   {
 416     const int shmid = ::shmget(IPC_PRIVATE, 1, IPC_CREAT | S_IRUSR | S_IWUSR);
 417     guarantee(shmid != -1, "shmget failed");
 418     void* p = ::shmat(shmid, NULL, 0);
 419     ::shmctl(shmid, IPC_RMID, NULL);
 420     guarantee(p != (void*) -1, "shmat failed");
 421     g_multipage_support.shmpsize = os::Aix::query_pagesize(p);
 422     ::shmdt(p);
 423   }
 424 
 425   // Before querying the stack page size, make sure we are not running as primordial
 426   // thread (because primordial thread's stack may have different page size than
 427   // pthread thread stacks). Running a VM on the primordial thread won't work for a
 428   // number of reasons so we may just as well guarantee it here.
 429   guarantee0(!os::is_primordial_thread());
 430 
 431   // Query pthread stack page size. Should be the same as data page size because
 432   // pthread stacks are allocated from C-Heap.
 433   {
 434     int dummy = 0;
 435     g_multipage_support.pthr_stack_pagesize = os::Aix::query_pagesize(&dummy);
 436   }
 437 
 438   // Query default text page size (LDR_CNTRL TEXTPSIZE).
 439   {
 440     address any_function =
 441       resolve_function_descriptor_to_code_pointer((address)describe_pagesize);
 442     g_multipage_support.textpsize = os::Aix::query_pagesize(any_function);
 443   }
 444 
 445   // Now probe for support of 64K pages and 16M pages.
 446 
 447   // Before OS/400 V6R1, there is no support for pages other than 4K.
 448   if (os::Aix::on_pase_V5R4_or_older()) {
 449     trcVerbose("OS/400 < V6R1 - no large page support.");
 450     g_multipage_support.error = ERROR_MP_OS_TOO_OLD;
 451     goto query_multipage_support_end;
 452   }
 453 
 454   // Now check which page sizes the OS claims it supports, and of those, which actually can be used.
 455   {
 456     const int MAX_PAGE_SIZES = 4;
 457     psize_t sizes[MAX_PAGE_SIZES];
 458     const int num_psizes = checked_vmgetinfo(sizes, VMINFO_GETPSIZES, MAX_PAGE_SIZES);
 459     if (num_psizes == -1) {
 460       trcVerbose("vmgetinfo(VMINFO_GETPSIZES) failed (errno: %d)", errno);
 461       trcVerbose("disabling multipage support.");
 462       g_multipage_support.error = ERROR_MP_VMGETINFO_FAILED;
 463       goto query_multipage_support_end;
 464     }
 465     guarantee(num_psizes > 0, "vmgetinfo(.., VMINFO_GETPSIZES, ...) failed.");
 466     assert(num_psizes <= MAX_PAGE_SIZES, "Surprise! more than 4 page sizes?");
 467     trcVerbose("vmgetinfo(.., VMINFO_GETPSIZES, ...) returns %d supported page sizes: ", num_psizes);
 468     for (int i = 0; i < num_psizes; i ++) {
 469       trcVerbose(" %s ", describe_pagesize(sizes[i]));
 470     }
 471 
 472     // Can we use 64K, 16M pages?
 473     for (int i = 0; i < num_psizes; i ++) {
 474       const size_t pagesize = sizes[i];
 475       if (pagesize != 64*K && pagesize != 16*M) {
 476         continue;
 477       }
 478       bool can_use = false;
 479       trcVerbose("Probing support for %s pages...", describe_pagesize(pagesize));
 480       const int shmid = ::shmget(IPC_PRIVATE, pagesize,
 481         IPC_CREAT | S_IRUSR | S_IWUSR);
 482       guarantee0(shmid != -1); // Should always work.
 483       // Try to set pagesize.
 484       struct shmid_ds shm_buf = { 0 };
 485       shm_buf.shm_pagesize = pagesize;
 486       if (::shmctl(shmid, SHM_PAGESIZE, &shm_buf) != 0) {
 487         const int en = errno;
 488         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 489         trcVerbose("shmctl(SHM_PAGESIZE) failed with errno=%n",
 490           errno);
 491       } else {
 492         // Attach and double check pageisze.
 493         void* p = ::shmat(shmid, NULL, 0);
 494         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 495         guarantee0(p != (void*) -1); // Should always work.
 496         const size_t real_pagesize = os::Aix::query_pagesize(p);
 497         if (real_pagesize != pagesize) {
 498           trcVerbose("real page size (0x%llX) differs.", real_pagesize);
 499         } else {
 500           can_use = true;
 501         }
 502         ::shmdt(p);
 503       }
 504       trcVerbose("Can use: %s", (can_use ? "yes" : "no"));
 505       if (pagesize == 64*K) {
 506         g_multipage_support.can_use_64K_pages = can_use;
 507       } else if (pagesize == 16*M) {
 508         g_multipage_support.can_use_16M_pages = can_use;
 509       }
 510     }
 511 
 512   } // end: check which pages can be used for shared memory
 513 
 514 query_multipage_support_end:
 515 
 516   trcVerbose("base page size (sysconf _SC_PAGESIZE): %s",
 517       describe_pagesize(g_multipage_support.pagesize));
 518   trcVerbose("Data page size (C-Heap, bss, etc): %s",
 519       describe_pagesize(g_multipage_support.datapsize));
 520   trcVerbose("Text page size: %s",
 521       describe_pagesize(g_multipage_support.textpsize));
 522   trcVerbose("Thread stack page size (pthread): %s",
 523       describe_pagesize(g_multipage_support.pthr_stack_pagesize));
 524   trcVerbose("Default shared memory page size: %s",
 525       describe_pagesize(g_multipage_support.shmpsize));
 526   trcVerbose("Can use 64K pages dynamically with shared meory: %s",
 527       (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
 528   trcVerbose("Can use 16M pages dynamically with shared memory: %s",
 529       (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
 530   trcVerbose("Multipage error details: %d",
 531       g_multipage_support.error);
 532 
 533   // sanity checks
 534   assert0(g_multipage_support.pagesize == 4*K);
 535   assert0(g_multipage_support.datapsize == 4*K || g_multipage_support.datapsize == 64*K);
 536   assert0(g_multipage_support.textpsize == 4*K || g_multipage_support.textpsize == 64*K);
 537   assert0(g_multipage_support.pthr_stack_pagesize == g_multipage_support.datapsize);
 538   assert0(g_multipage_support.shmpsize == 4*K || g_multipage_support.shmpsize == 64*K);
 539 
 540 }
 541 
 542 void os::init_system_properties_values() {
 543 
 544 #define DEFAULT_LIBPATH "/lib:/usr/lib"
 545 #define EXTENSIONS_DIR  "/lib/ext"
 546 
 547   // Buffer that fits several sprintfs.
 548   // Note that the space for the trailing null is provided
 549   // by the nulls included by the sizeof operator.
 550   const size_t bufsize =
 551     MAX2((size_t)MAXPATHLEN,  // For dll_dir & friends.
 552          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR)); // extensions dir
 553   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 554 
 555   // sysclasspath, java_home, dll_dir
 556   {
 557     char *pslash;
 558     os::jvm_path(buf, bufsize);
 559 
 560     // Found the full path to libjvm.so.
 561     // Now cut the path to <java_home>/jre if we can.
 562     pslash = strrchr(buf, '/');
 563     if (pslash != NULL) {
 564       *pslash = '\0';            // Get rid of /libjvm.so.
 565     }
 566     pslash = strrchr(buf, '/');
 567     if (pslash != NULL) {
 568       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 569     }
 570     Arguments::set_dll_dir(buf);
 571 
 572     if (pslash != NULL) {
 573       pslash = strrchr(buf, '/');
 574       if (pslash != NULL) {
 575         *pslash = '\0';        // Get rid of /lib.
 576       }
 577     }
 578     Arguments::set_java_home(buf);
 579     set_boot_path('/', ':');
 580   }
 581 
 582   // Where to look for native libraries.
 583 
 584   // On Aix we get the user setting of LIBPATH.
 585   // Eventually, all the library path setting will be done here.
 586   // Get the user setting of LIBPATH.
 587   const char *v = ::getenv("LIBPATH");
 588   const char *v_colon = ":";
 589   if (v == NULL) { v = ""; v_colon = ""; }
 590 
 591   // Concatenate user and invariant part of ld_library_path.
 592   // That's +1 for the colon and +1 for the trailing '\0'.
 593   char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, strlen(v) + 1 + sizeof(DEFAULT_LIBPATH) + 1, mtInternal);
 594   sprintf(ld_library_path, "%s%s" DEFAULT_LIBPATH, v, v_colon);
 595   Arguments::set_library_path(ld_library_path);
 596   FREE_C_HEAP_ARRAY(char, ld_library_path);
 597 
 598   // Extensions directories.
 599   sprintf(buf, "%s" EXTENSIONS_DIR, Arguments::get_java_home());
 600   Arguments::set_ext_dirs(buf);
 601 
 602   FREE_C_HEAP_ARRAY(char, buf);
 603 
 604 #undef DEFAULT_LIBPATH
 605 #undef EXTENSIONS_DIR
 606 }
 607 
 608 ////////////////////////////////////////////////////////////////////////////////
 609 // breakpoint support
 610 
 611 void os::breakpoint() {
 612   BREAKPOINT;
 613 }
 614 
 615 extern "C" void breakpoint() {
 616   // use debugger to set breakpoint here
 617 }
 618 
 619 ////////////////////////////////////////////////////////////////////////////////
 620 // signal support
 621 
 622 debug_only(static bool signal_sets_initialized = false);
 623 static sigset_t unblocked_sigs, vm_sigs;
 624 
 625 bool os::Aix::is_sig_ignored(int sig) {
 626   struct sigaction oact;
 627   sigaction(sig, (struct sigaction*)NULL, &oact);
 628   void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
 629     : CAST_FROM_FN_PTR(void*, oact.sa_handler);
 630   if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
 631     return true;
 632   } else {
 633     return false;
 634   }
 635 }
 636 
 637 void os::Aix::signal_sets_init() {
 638   // Should also have an assertion stating we are still single-threaded.
 639   assert(!signal_sets_initialized, "Already initialized");
 640   // Fill in signals that are necessarily unblocked for all threads in
 641   // the VM. Currently, we unblock the following signals:
 642   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 643   //                         by -Xrs (=ReduceSignalUsage));
 644   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 645   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 646   // the dispositions or masks wrt these signals.
 647   // Programs embedding the VM that want to use the above signals for their
 648   // own purposes must, at this time, use the "-Xrs" option to prevent
 649   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 650   // (See bug 4345157, and other related bugs).
 651   // In reality, though, unblocking these signals is really a nop, since
 652   // these signals are not blocked by default.
 653   sigemptyset(&unblocked_sigs);
 654   sigaddset(&unblocked_sigs, SIGILL);
 655   sigaddset(&unblocked_sigs, SIGSEGV);
 656   sigaddset(&unblocked_sigs, SIGBUS);
 657   sigaddset(&unblocked_sigs, SIGFPE);
 658   sigaddset(&unblocked_sigs, SIGTRAP);
 659   sigaddset(&unblocked_sigs, SR_signum);
 660 
 661   if (!ReduceSignalUsage) {
 662    if (!os::Aix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 663      sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 664    }
 665    if (!os::Aix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 666      sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 667    }
 668    if (!os::Aix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 669      sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 670    }
 671   }
 672   // Fill in signals that are blocked by all but the VM thread.
 673   sigemptyset(&vm_sigs);
 674   if (!ReduceSignalUsage)
 675     sigaddset(&vm_sigs, BREAK_SIGNAL);
 676   debug_only(signal_sets_initialized = true);
 677 }
 678 
 679 // These are signals that are unblocked while a thread is running Java.
 680 // (For some reason, they get blocked by default.)
 681 sigset_t* os::Aix::unblocked_signals() {
 682   assert(signal_sets_initialized, "Not initialized");
 683   return &unblocked_sigs;
 684 }
 685 
 686 // These are the signals that are blocked while a (non-VM) thread is
 687 // running Java. Only the VM thread handles these signals.
 688 sigset_t* os::Aix::vm_signals() {
 689   assert(signal_sets_initialized, "Not initialized");
 690   return &vm_sigs;
 691 }
 692 
 693 void os::Aix::hotspot_sigmask(Thread* thread) {
 694 
 695   //Save caller's signal mask before setting VM signal mask
 696   sigset_t caller_sigmask;
 697   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 698 
 699   OSThread* osthread = thread->osthread();
 700   osthread->set_caller_sigmask(caller_sigmask);
 701 
 702   pthread_sigmask(SIG_UNBLOCK, os::Aix::unblocked_signals(), NULL);
 703 
 704   if (!ReduceSignalUsage) {
 705     if (thread->is_VM_thread()) {
 706       // Only the VM thread handles BREAK_SIGNAL ...
 707       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 708     } else {
 709       // ... all other threads block BREAK_SIGNAL
 710       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 711     }
 712   }
 713 }
 714 
 715 // retrieve memory information.
 716 // Returns false if something went wrong;
 717 // content of pmi undefined in this case.
 718 bool os::Aix::get_meminfo(meminfo_t* pmi) {
 719 
 720   assert(pmi, "get_meminfo: invalid parameter");
 721 
 722   memset(pmi, 0, sizeof(meminfo_t));
 723 
 724   if (os::Aix::on_pase()) {
 725     // On PASE, use the libo4 porting library.
 726 
 727     unsigned long long virt_total = 0;
 728     unsigned long long real_total = 0;
 729     unsigned long long real_free = 0;
 730     unsigned long long pgsp_total = 0;
 731     unsigned long long pgsp_free = 0;
 732     if (libo4::get_memory_info(&virt_total, &real_total, &real_free, &pgsp_total, &pgsp_free)) {
 733       pmi->virt_total = virt_total;
 734       pmi->real_total = real_total;
 735       pmi->real_free = real_free;
 736       pmi->pgsp_total = pgsp_total;
 737       pmi->pgsp_free = pgsp_free;
 738       return true;
 739     }
 740     return false;
 741 
 742   } else {
 743 
 744     // On AIX, I use the (dynamically loaded) perfstat library to retrieve memory statistics
 745     // See:
 746     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 747     //        ?topic=/com.ibm.aix.basetechref/doc/basetrf1/perfstat_memtot.htm
 748     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 749     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 750 
 751     perfstat_memory_total_t psmt;
 752     memset (&psmt, '\0', sizeof(psmt));
 753     const int rc = libperfstat::perfstat_memory_total(NULL, &psmt, sizeof(psmt), 1);
 754     if (rc == -1) {
 755       trcVerbose("perfstat_memory_total() failed (errno=%d)", errno);
 756       assert(0, "perfstat_memory_total() failed");
 757       return false;
 758     }
 759 
 760     assert(rc == 1, "perfstat_memory_total() - weird return code");
 761 
 762     // excerpt from
 763     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 764     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 765     // The fields of perfstat_memory_total_t:
 766     // u_longlong_t virt_total         Total virtual memory (in 4 KB pages).
 767     // u_longlong_t real_total         Total real memory (in 4 KB pages).
 768     // u_longlong_t real_free          Free real memory (in 4 KB pages).
 769     // u_longlong_t pgsp_total         Total paging space (in 4 KB pages).
 770     // u_longlong_t pgsp_free          Free paging space (in 4 KB pages).
 771 
 772     pmi->virt_total = psmt.virt_total * 4096;
 773     pmi->real_total = psmt.real_total * 4096;
 774     pmi->real_free = psmt.real_free * 4096;
 775     pmi->pgsp_total = psmt.pgsp_total * 4096;
 776     pmi->pgsp_free = psmt.pgsp_free * 4096;
 777 
 778     return true;
 779 
 780   }
 781 } // end os::Aix::get_meminfo
 782 
 783 //////////////////////////////////////////////////////////////////////////////
 784 // create new thread
 785 
 786 // Thread start routine for all newly created threads
 787 static void *thread_native_entry(Thread *thread) {
 788 
 789   // find out my own stack dimensions
 790   {
 791     // actually, this should do exactly the same as thread->record_stack_base_and_size...
 792     thread->set_stack_base(os::current_stack_base());
 793     thread->set_stack_size(os::current_stack_size());
 794   }
 795 
 796   const pthread_t pthread_id = ::pthread_self();
 797   const tid_t kernel_thread_id = ::thread_self();
 798 
 799   LogTarget(Info, os, thread) lt;
 800   if (lt.is_enabled()) {
 801     address low_address = thread->stack_end();
 802     address high_address = thread->stack_base();
 803     lt.print("Thread is alive (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT
 804              ", stack [" PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "k using %uk pages)).",
 805              os::current_thread_id(), (uintx) kernel_thread_id, low_address, high_address,
 806              (high_address - low_address) / K, os::Aix::query_pagesize(low_address) / K);
 807   }
 808 
 809   // Normally, pthread stacks on AIX live in the data segment (are allocated with malloc()
 810   // by the pthread library). In rare cases, this may not be the case, e.g. when third-party
 811   // tools hook pthread_create(). In this case, we may run into problems establishing
 812   // guard pages on those stacks, because the stacks may reside in memory which is not
 813   // protectable (shmated).
 814   if (thread->stack_base() > ::sbrk(0)) {
 815     log_warning(os, thread)("Thread stack not in data segment.");
 816   }
 817 
 818   // Try to randomize the cache line index of hot stack frames.
 819   // This helps when threads of the same stack traces evict each other's
 820   // cache lines. The threads can be either from the same JVM instance, or
 821   // from different JVM instances. The benefit is especially true for
 822   // processors with hyperthreading technology.
 823 
 824   static int counter = 0;
 825   int pid = os::current_process_id();
 826   alloca(((pid ^ counter++) & 7) * 128);
 827 
 828   thread->initialize_thread_current();
 829 
 830   OSThread* osthread = thread->osthread();
 831 
 832   // Thread_id is pthread id.
 833   osthread->set_thread_id(pthread_id);
 834 
 835   // .. but keep kernel thread id too for diagnostics
 836   osthread->set_kernel_thread_id(kernel_thread_id);
 837 
 838   // Initialize signal mask for this thread.
 839   os::Aix::hotspot_sigmask(thread);
 840 
 841   // Initialize floating point control register.
 842   os::Aix::init_thread_fpu_state();
 843 
 844   assert(osthread->get_state() == RUNNABLE, "invalid os thread state");
 845 
 846   // Call one more level start routine.
 847   thread->run();
 848 
 849   log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 850     os::current_thread_id(), (uintx) kernel_thread_id);
 851 
 852   // If a thread has not deleted itself ("delete this") as part of its
 853   // termination sequence, we have to ensure thread-local-storage is
 854   // cleared before we actually terminate. No threads should ever be
 855   // deleted asynchronously with respect to their termination.
 856   if (Thread::current_or_null_safe() != NULL) {
 857     assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
 858     thread->clear_thread_current();
 859   }
 860 
 861   return 0;
 862 }
 863 
 864 bool os::create_thread(Thread* thread, ThreadType thr_type,
 865                        size_t req_stack_size) {
 866 
 867   assert(thread->osthread() == NULL, "caller responsible");
 868 
 869   // Allocate the OSThread object.
 870   OSThread* osthread = new OSThread(NULL, NULL);
 871   if (osthread == NULL) {
 872     return false;
 873   }
 874 
 875   // Set the correct thread state.
 876   osthread->set_thread_type(thr_type);
 877 
 878   // Initial state is ALLOCATED but not INITIALIZED
 879   osthread->set_state(ALLOCATED);
 880 
 881   thread->set_osthread(osthread);
 882 
 883   // Init thread attributes.
 884   pthread_attr_t attr;
 885   pthread_attr_init(&attr);
 886   guarantee(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0, "???");
 887 
 888   // Make sure we run in 1:1 kernel-user-thread mode.
 889   if (os::Aix::on_aix()) {
 890     guarantee(pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) == 0, "???");
 891     guarantee(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0, "???");
 892   }
 893 
 894   // Start in suspended state, and in os::thread_start, wake the thread up.
 895   guarantee(pthread_attr_setsuspendstate_np(&attr, PTHREAD_CREATE_SUSPENDED_NP) == 0, "???");
 896 
 897   // Calculate stack size if it's not specified by caller.
 898   size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
 899 
 900   // JDK-8187028: It was observed that on some configurations (4K backed thread stacks)
 901   // the real thread stack size may be smaller than the requested stack size, by as much as 64K.
 902   // This very much looks like a pthread lib error. As a workaround, increase the stack size
 903   // by 64K for small thread stacks (arbitrarily choosen to be < 4MB)
 904   if (stack_size < 4096 * K) {
 905     stack_size += 64 * K;
 906   }
 907 
 908   // On Aix, pthread_attr_setstacksize fails with huge values and leaves the
 909   // thread size in attr unchanged. If this is the minimal stack size as set
 910   // by pthread_attr_init this leads to crashes after thread creation. E.g. the
 911   // guard pages might not fit on the tiny stack created.
 912   int ret = pthread_attr_setstacksize(&attr, stack_size);
 913   if (ret != 0) {
 914     log_warning(os, thread)("The thread stack size specified is invalid: " SIZE_FORMAT "k",
 915                             stack_size / K);
 916   }
 917 
 918   // Save some cycles and a page by disabling OS guard pages where we have our own
 919   // VM guard pages (in java threads). For other threads, keep system default guard
 920   // pages in place.
 921   if (thr_type == java_thread || thr_type == compiler_thread) {
 922     ret = pthread_attr_setguardsize(&attr, 0);
 923   }
 924 
 925   pthread_t tid = 0;
 926   if (ret == 0) {
 927     ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
 928   }
 929 
 930   if (ret == 0) {
 931     char buf[64];
 932     log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
 933       (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 934   } else {
 935     char buf[64];
 936     log_warning(os, thread)("Failed to start thread - pthread_create failed (%d=%s) for attributes: %s.",
 937       ret, os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 938   }
 939 
 940   pthread_attr_destroy(&attr);
 941 
 942   if (ret != 0) {
 943     // Need to clean up stuff we've allocated so far.
 944     thread->set_osthread(NULL);
 945     delete osthread;
 946     return false;
 947   }
 948 
 949   // OSThread::thread_id is the pthread id.
 950   osthread->set_thread_id(tid);
 951 
 952   return true;
 953 }
 954 
 955 /////////////////////////////////////////////////////////////////////////////
 956 // attach existing thread
 957 
 958 // bootstrap the main thread
 959 bool os::create_main_thread(JavaThread* thread) {
 960   assert(os::Aix::_main_thread == pthread_self(), "should be called inside main thread");
 961   return create_attached_thread(thread);
 962 }
 963 
 964 bool os::create_attached_thread(JavaThread* thread) {
 965 #ifdef ASSERT
 966     thread->verify_not_published();
 967 #endif
 968 
 969   // Allocate the OSThread object
 970   OSThread* osthread = new OSThread(NULL, NULL);
 971 
 972   if (osthread == NULL) {
 973     return false;
 974   }
 975 
 976   const pthread_t pthread_id = ::pthread_self();
 977   const tid_t kernel_thread_id = ::thread_self();
 978 
 979   // OSThread::thread_id is the pthread id.
 980   osthread->set_thread_id(pthread_id);
 981 
 982   // .. but keep kernel thread id too for diagnostics
 983   osthread->set_kernel_thread_id(kernel_thread_id);
 984 
 985   // initialize floating point control register
 986   os::Aix::init_thread_fpu_state();
 987 
 988   // Initial thread state is RUNNABLE
 989   osthread->set_state(RUNNABLE);
 990 
 991   thread->set_osthread(osthread);
 992 
 993   if (UseNUMA) {
 994     int lgrp_id = os::numa_get_group_id();
 995     if (lgrp_id != -1) {
 996       thread->set_lgrp_id(lgrp_id);
 997     }
 998   }
 999 
1000   // initialize signal mask for this thread
1001   // and save the caller's signal mask
1002   os::Aix::hotspot_sigmask(thread);
1003 
1004   log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
1005     os::current_thread_id(), (uintx) kernel_thread_id);
1006 
1007   return true;
1008 }
1009 
1010 void os::pd_start_thread(Thread* thread) {
1011   int status = pthread_continue_np(thread->osthread()->pthread_id());
1012   assert(status == 0, "thr_continue failed");
1013 }
1014 
1015 // Free OS resources related to the OSThread
1016 void os::free_thread(OSThread* osthread) {
1017   assert(osthread != NULL, "osthread not set");
1018 
1019   // We are told to free resources of the argument thread,
1020   // but we can only really operate on the current thread.
1021   assert(Thread::current()->osthread() == osthread,
1022          "os::free_thread but not current thread");
1023 
1024   // Restore caller's signal mask
1025   sigset_t sigmask = osthread->caller_sigmask();
1026   pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1027 
1028   delete osthread;
1029 }
1030 
1031 ////////////////////////////////////////////////////////////////////////////////
1032 // time support
1033 
1034 // Time since start-up in seconds to a fine granularity.
1035 // Used by VMSelfDestructTimer and the MemProfiler.
1036 double os::elapsedTime() {
1037   return (double)(os::elapsed_counter()) * 0.000001;
1038 }
1039 
1040 jlong os::elapsed_counter() {
1041   timeval time;
1042   int status = gettimeofday(&time, NULL);
1043   return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1044 }
1045 
1046 jlong os::elapsed_frequency() {
1047   return (1000 * 1000);
1048 }
1049 
1050 bool os::supports_vtime() { return true; }
1051 bool os::enable_vtime()   { return false; }
1052 bool os::vtime_enabled()  { return false; }
1053 
1054 double os::elapsedVTime() {
1055   struct rusage usage;
1056   int retval = getrusage(RUSAGE_THREAD, &usage);
1057   if (retval == 0) {
1058     return usage.ru_utime.tv_sec + usage.ru_stime.tv_sec + (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000.0 * 1000);
1059   } else {
1060     // better than nothing, but not much
1061     return elapsedTime();
1062   }
1063 }
1064 
1065 jlong os::javaTimeMillis() {
1066   timeval time;
1067   int status = gettimeofday(&time, NULL);
1068   assert(status != -1, "aix error at gettimeofday()");
1069   return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1070 }
1071 
1072 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1073   timeval time;
1074   int status = gettimeofday(&time, NULL);
1075   assert(status != -1, "aix error at gettimeofday()");
1076   seconds = jlong(time.tv_sec);
1077   nanos = jlong(time.tv_usec) * 1000;
1078 }
1079 
1080 // We use mread_real_time here.
1081 // On AIX: If the CPU has a time register, the result will be RTC_POWER and
1082 // it has to be converted to real time. AIX documentations suggests to do
1083 // this unconditionally, so we do it.
1084 //
1085 // See: https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf2/read_real_time.htm
1086 //
1087 // On PASE: mread_real_time will always return RTC_POWER_PC data, so no
1088 // conversion is necessary. However, mread_real_time will not return
1089 // monotonic results but merely matches read_real_time. So we need a tweak
1090 // to ensure monotonic results.
1091 //
1092 // For PASE no public documentation exists, just word by IBM
1093 jlong os::javaTimeNanos() {
1094   timebasestruct_t time;
1095   int rc = mread_real_time(&time, TIMEBASE_SZ);
1096   if (os::Aix::on_pase()) {
1097     assert(rc == RTC_POWER, "expected time format RTC_POWER from mread_real_time in PASE");
1098     jlong now = jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1099     jlong prev = max_real_time;
1100     if (now <= prev) {
1101       return prev;   // same or retrograde time;
1102     }
1103     jlong obsv = Atomic::cmpxchg(now, &max_real_time, prev);
1104     assert(obsv >= prev, "invariant");   // Monotonicity
1105     // If the CAS succeeded then we're done and return "now".
1106     // If the CAS failed and the observed value "obsv" is >= now then
1107     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1108     // some other thread raced this thread and installed a new value, in which case
1109     // we could either (a) retry the entire operation, (b) retry trying to install now
1110     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1111     // we might discard a higher "now" value in deference to a slightly lower but freshly
1112     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1113     // to (a) or (b) -- and greatly reduces coherence traffic.
1114     // We might also condition (c) on the magnitude of the delta between obsv and now.
1115     // Avoiding excessive CAS operations to hot RW locations is critical.
1116     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1117     return (prev == obsv) ? now : obsv;
1118   } else {
1119     if (rc != RTC_POWER) {
1120       rc = time_base_to_time(&time, TIMEBASE_SZ);
1121       assert(rc != -1, "error calling time_base_to_time()");
1122     }
1123     return jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1124   }
1125 }
1126 
1127 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1128   info_ptr->max_value = ALL_64_BITS;
1129   // mread_real_time() is monotonic (see 'os::javaTimeNanos()')
1130   info_ptr->may_skip_backward = false;
1131   info_ptr->may_skip_forward = false;
1132   info_ptr->kind = JVMTI_TIMER_ELAPSED;    // elapsed not CPU time
1133 }
1134 
1135 // Return the real, user, and system times in seconds from an
1136 // arbitrary fixed point in the past.
1137 bool os::getTimesSecs(double* process_real_time,
1138                       double* process_user_time,
1139                       double* process_system_time) {
1140   struct tms ticks;
1141   clock_t real_ticks = times(&ticks);
1142 
1143   if (real_ticks == (clock_t) (-1)) {
1144     return false;
1145   } else {
1146     double ticks_per_second = (double) clock_tics_per_sec;
1147     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1148     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1149     *process_real_time = ((double) real_ticks) / ticks_per_second;
1150 
1151     return true;
1152   }
1153 }
1154 
1155 char * os::local_time_string(char *buf, size_t buflen) {
1156   struct tm t;
1157   time_t long_time;
1158   time(&long_time);
1159   localtime_r(&long_time, &t);
1160   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1161                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1162                t.tm_hour, t.tm_min, t.tm_sec);
1163   return buf;
1164 }
1165 
1166 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1167   return localtime_r(clock, res);
1168 }
1169 
1170 ////////////////////////////////////////////////////////////////////////////////
1171 // runtime exit support
1172 
1173 // Note: os::shutdown() might be called very early during initialization, or
1174 // called from signal handler. Before adding something to os::shutdown(), make
1175 // sure it is async-safe and can handle partially initialized VM.
1176 void os::shutdown() {
1177 
1178   // allow PerfMemory to attempt cleanup of any persistent resources
1179   perfMemory_exit();
1180 
1181   // needs to remove object in file system
1182   AttachListener::abort();
1183 
1184   // flush buffered output, finish log files
1185   ostream_abort();
1186 
1187   // Check for abort hook
1188   abort_hook_t abort_hook = Arguments::abort_hook();
1189   if (abort_hook != NULL) {
1190     abort_hook();
1191   }
1192 }
1193 
1194 // Note: os::abort() might be called very early during initialization, or
1195 // called from signal handler. Before adding something to os::abort(), make
1196 // sure it is async-safe and can handle partially initialized VM.
1197 void os::abort(bool dump_core, void* siginfo, const void* context) {
1198   os::shutdown();
1199   if (dump_core) {
1200 #ifndef PRODUCT
1201     fdStream out(defaultStream::output_fd());
1202     out.print_raw("Current thread is ");
1203     char buf[16];
1204     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1205     out.print_raw_cr(buf);
1206     out.print_raw_cr("Dumping core ...");
1207 #endif
1208     ::abort(); // dump core
1209   }
1210 
1211   ::exit(1);
1212 }
1213 
1214 // Die immediately, no exit hook, no abort hook, no cleanup.
1215 void os::die() {
1216   ::abort();
1217 }
1218 
1219 // This method is a copy of JDK's sysGetLastErrorString
1220 // from src/solaris/hpi/src/system_md.c
1221 
1222 size_t os::lasterror(char *buf, size_t len) {
1223   if (errno == 0) return 0;
1224 
1225   const char *s = os::strerror(errno);
1226   size_t n = ::strlen(s);
1227   if (n >= len) {
1228     n = len - 1;
1229   }
1230   ::strncpy(buf, s, n);
1231   buf[n] = '\0';
1232   return n;
1233 }
1234 
1235 intx os::current_thread_id() {
1236   return (intx)pthread_self();
1237 }
1238 
1239 int os::current_process_id() {
1240   return getpid();
1241 }
1242 
1243 // DLL functions
1244 
1245 const char* os::dll_file_extension() { return ".so"; }
1246 
1247 // This must be hard coded because it's the system's temporary
1248 // directory not the java application's temp directory, ala java.io.tmpdir.
1249 const char* os::get_temp_directory() { return "/tmp"; }
1250 
1251 // Check if addr is inside libjvm.so.
1252 bool os::address_is_in_vm(address addr) {
1253 
1254   // Input could be a real pc or a function pointer literal. The latter
1255   // would be a function descriptor residing in the data segment of a module.
1256   loaded_module_t lm;
1257   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL) {
1258     return lm.is_in_vm;
1259   } else if (LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
1260     return lm.is_in_vm;
1261   } else {
1262     return false;
1263   }
1264 
1265 }
1266 
1267 // Resolve an AIX function descriptor literal to a code pointer.
1268 // If the input is a valid code pointer to a text segment of a loaded module,
1269 //   it is returned unchanged.
1270 // If the input is a valid AIX function descriptor, it is resolved to the
1271 //   code entry point.
1272 // If the input is neither a valid function descriptor nor a valid code pointer,
1273 //   NULL is returned.
1274 static address resolve_function_descriptor_to_code_pointer(address p) {
1275 
1276   if (LoadedLibraries::find_for_text_address(p, NULL) != NULL) {
1277     // It is a real code pointer.
1278     return p;
1279   } else if (LoadedLibraries::find_for_data_address(p, NULL) != NULL) {
1280     // Pointer to data segment, potential function descriptor.
1281     address code_entry = (address)(((FunctionDescriptor*)p)->entry());
1282     if (LoadedLibraries::find_for_text_address(code_entry, NULL) != NULL) {
1283       // It is a function descriptor.
1284       return code_entry;
1285     }
1286   }
1287 
1288   return NULL;
1289 }
1290 
1291 bool os::dll_address_to_function_name(address addr, char *buf,
1292                                       int buflen, int *offset,
1293                                       bool demangle) {
1294   if (offset) {
1295     *offset = -1;
1296   }
1297   // Buf is not optional, but offset is optional.
1298   assert(buf != NULL, "sanity check");
1299   buf[0] = '\0';
1300 
1301   // Resolve function ptr literals first.
1302   addr = resolve_function_descriptor_to_code_pointer(addr);
1303   if (!addr) {
1304     return false;
1305   }
1306 
1307   return AixSymbols::get_function_name(addr, buf, buflen, offset, NULL, demangle);
1308 }
1309 
1310 bool os::dll_address_to_library_name(address addr, char* buf,
1311                                      int buflen, int* offset) {
1312   if (offset) {
1313     *offset = -1;
1314   }
1315   // Buf is not optional, but offset is optional.
1316   assert(buf != NULL, "sanity check");
1317   buf[0] = '\0';
1318 
1319   // Resolve function ptr literals first.
1320   addr = resolve_function_descriptor_to_code_pointer(addr);
1321   if (!addr) {
1322     return false;
1323   }
1324 
1325   return AixSymbols::get_module_name(addr, buf, buflen);
1326 }
1327 
1328 // Loads .dll/.so and in case of error it checks if .dll/.so was built
1329 // for the same architecture as Hotspot is running on.
1330 void *os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1331 
1332   if (ebuf && ebuflen > 0) {
1333     ebuf[0] = '\0';
1334     ebuf[ebuflen - 1] = '\0';
1335   }
1336 
1337   if (!filename || strlen(filename) == 0) {
1338     ::strncpy(ebuf, "dll_load: empty filename specified", ebuflen - 1);
1339     return NULL;
1340   }
1341 
1342   // RTLD_LAZY is currently not implemented. The dl is loaded immediately with all its dependants.
1343   void * result= ::dlopen(filename, RTLD_LAZY);
1344   if (result != NULL) {
1345     // Reload dll cache. Don't do this in signal handling.
1346     LoadedLibraries::reload();
1347     return result;
1348   } else {
1349     // error analysis when dlopen fails
1350     const char* const error_report = ::dlerror();
1351     if (error_report && ebuf && ebuflen > 0) {
1352       snprintf(ebuf, ebuflen - 1, "%s, LIBPATH=%s, LD_LIBRARY_PATH=%s : %s",
1353                filename, ::getenv("LIBPATH"), ::getenv("LD_LIBRARY_PATH"), error_report);
1354     }
1355   }
1356   return NULL;
1357 }
1358 
1359 void* os::dll_lookup(void* handle, const char* name) {
1360   void* res = dlsym(handle, name);
1361   return res;
1362 }
1363 
1364 void* os::get_default_process_handle() {
1365   return (void*)::dlopen(NULL, RTLD_LAZY);
1366 }
1367 
1368 void os::print_dll_info(outputStream *st) {
1369   st->print_cr("Dynamic libraries:");
1370   LoadedLibraries::print(st);
1371 }
1372 
1373 void os::get_summary_os_info(char* buf, size_t buflen) {
1374   // There might be something more readable than uname results for AIX.
1375   struct utsname name;
1376   uname(&name);
1377   snprintf(buf, buflen, "%s %s", name.release, name.version);
1378 }
1379 
1380 void os::print_os_info(outputStream* st) {
1381   st->print("OS:");
1382 
1383   st->print("uname:");
1384   struct utsname name;
1385   uname(&name);
1386   st->print(name.sysname); st->print(" ");
1387   st->print(name.nodename); st->print(" ");
1388   st->print(name.release); st->print(" ");
1389   st->print(name.version); st->print(" ");
1390   st->print(name.machine);
1391   st->cr();
1392 
1393   uint32_t ver = os::Aix::os_version();
1394   st->print_cr("AIX kernel version %u.%u.%u.%u",
1395                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1396 
1397   os::Posix::print_rlimit_info(st);
1398 
1399   // load average
1400   st->print("load average:");
1401   double loadavg[3] = {-1.L, -1.L, -1.L};
1402   os::loadavg(loadavg, 3);
1403   st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1404   st->cr();
1405 
1406   // print wpar info
1407   libperfstat::wparinfo_t wi;
1408   if (libperfstat::get_wparinfo(&wi)) {
1409     st->print_cr("wpar info");
1410     st->print_cr("name: %s", wi.name);
1411     st->print_cr("id:   %d", wi.wpar_id);
1412     st->print_cr("type: %s", (wi.app_wpar ? "application" : "system"));
1413   }
1414 
1415   // print partition info
1416   libperfstat::partitioninfo_t pi;
1417   if (libperfstat::get_partitioninfo(&pi)) {
1418     st->print_cr("partition info");
1419     st->print_cr(" name: %s", pi.name);
1420   }
1421 
1422 }
1423 
1424 void os::print_memory_info(outputStream* st) {
1425 
1426   st->print_cr("Memory:");
1427 
1428   st->print_cr("  Base page size (sysconf _SC_PAGESIZE):  %s",
1429     describe_pagesize(g_multipage_support.pagesize));
1430   st->print_cr("  Data page size (C-Heap, bss, etc):      %s",
1431     describe_pagesize(g_multipage_support.datapsize));
1432   st->print_cr("  Text page size:                         %s",
1433     describe_pagesize(g_multipage_support.textpsize));
1434   st->print_cr("  Thread stack page size (pthread):       %s",
1435     describe_pagesize(g_multipage_support.pthr_stack_pagesize));
1436   st->print_cr("  Default shared memory page size:        %s",
1437     describe_pagesize(g_multipage_support.shmpsize));
1438   st->print_cr("  Can use 64K pages dynamically with shared meory:  %s",
1439     (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
1440   st->print_cr("  Can use 16M pages dynamically with shared memory: %s",
1441     (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
1442   st->print_cr("  Multipage error: %d",
1443     g_multipage_support.error);
1444   st->cr();
1445   st->print_cr("  os::vm_page_size:       %s", describe_pagesize(os::vm_page_size()));
1446 
1447   // print out LDR_CNTRL because it affects the default page sizes
1448   const char* const ldr_cntrl = ::getenv("LDR_CNTRL");
1449   st->print_cr("  LDR_CNTRL=%s.", ldr_cntrl ? ldr_cntrl : "<unset>");
1450 
1451   // Print out EXTSHM because it is an unsupported setting.
1452   const char* const extshm = ::getenv("EXTSHM");
1453   st->print_cr("  EXTSHM=%s.", extshm ? extshm : "<unset>");
1454   if ( (strcmp(extshm, "on") == 0) || (strcmp(extshm, "ON") == 0) ) {
1455     st->print_cr("  *** Unsupported! Please remove EXTSHM from your environment! ***");
1456   }
1457 
1458   // Print out AIXTHREAD_GUARDPAGES because it affects the size of pthread stacks.
1459   const char* const aixthread_guardpages = ::getenv("AIXTHREAD_GUARDPAGES");
1460   st->print_cr("  AIXTHREAD_GUARDPAGES=%s.",
1461       aixthread_guardpages ? aixthread_guardpages : "<unset>");
1462 
1463   os::Aix::meminfo_t mi;
1464   if (os::Aix::get_meminfo(&mi)) {
1465     if (os::Aix::on_aix()) {
1466       st->print_cr("physical total : " SIZE_FORMAT, mi.real_total);
1467       st->print_cr("physical free  : " SIZE_FORMAT, mi.real_free);
1468       st->print_cr("swap total     : " SIZE_FORMAT, mi.pgsp_total);
1469       st->print_cr("swap free      : " SIZE_FORMAT, mi.pgsp_free);
1470     } else {
1471       // PASE - Numbers are result of QWCRSSTS; they mean:
1472       // real_total: Sum of all system pools
1473       // real_free: always 0
1474       // pgsp_total: we take the size of the system ASP
1475       // pgsp_free: size of system ASP times percentage of system ASP unused
1476       st->print_cr("physical total     : " SIZE_FORMAT, mi.real_total);
1477       st->print_cr("system asp total   : " SIZE_FORMAT, mi.pgsp_total);
1478       st->print_cr("%% system asp used : %.2f",
1479         mi.pgsp_total ? (100.0f * (mi.pgsp_total - mi.pgsp_free) / mi.pgsp_total) : -1.0f);
1480     }
1481   }
1482   st->cr();
1483 
1484   // Print segments allocated with os::reserve_memory.
1485   st->print_cr("internal virtual memory regions used by vm:");
1486   vmembk_print_on(st);
1487 }
1488 
1489 // Get a string for the cpuinfo that is a summary of the cpu type
1490 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1491   // read _system_configuration.version
1492   switch (_system_configuration.version) {
1493   case PV_8:
1494     strncpy(buf, "Power PC 8", buflen);
1495     break;
1496   case PV_7:
1497     strncpy(buf, "Power PC 7", buflen);
1498     break;
1499   case PV_6_1:
1500     strncpy(buf, "Power PC 6 DD1.x", buflen);
1501     break;
1502   case PV_6:
1503     strncpy(buf, "Power PC 6", buflen);
1504     break;
1505   case PV_5:
1506     strncpy(buf, "Power PC 5", buflen);
1507     break;
1508   case PV_5_2:
1509     strncpy(buf, "Power PC 5_2", buflen);
1510     break;
1511   case PV_5_3:
1512     strncpy(buf, "Power PC 5_3", buflen);
1513     break;
1514   case PV_5_Compat:
1515     strncpy(buf, "PV_5_Compat", buflen);
1516     break;
1517   case PV_6_Compat:
1518     strncpy(buf, "PV_6_Compat", buflen);
1519     break;
1520   case PV_7_Compat:
1521     strncpy(buf, "PV_7_Compat", buflen);
1522     break;
1523   case PV_8_Compat:
1524     strncpy(buf, "PV_8_Compat", buflen);
1525     break;
1526   default:
1527     strncpy(buf, "unknown", buflen);
1528   }
1529 }
1530 
1531 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1532   // Nothing to do beyond of what os::print_cpu_info() does.
1533 }
1534 
1535 static void print_signal_handler(outputStream* st, int sig,
1536                                  char* buf, size_t buflen);
1537 
1538 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1539   st->print_cr("Signal Handlers:");
1540   print_signal_handler(st, SIGSEGV, buf, buflen);
1541   print_signal_handler(st, SIGBUS , buf, buflen);
1542   print_signal_handler(st, SIGFPE , buf, buflen);
1543   print_signal_handler(st, SIGPIPE, buf, buflen);
1544   print_signal_handler(st, SIGXFSZ, buf, buflen);
1545   print_signal_handler(st, SIGILL , buf, buflen);
1546   print_signal_handler(st, SR_signum, buf, buflen);
1547   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1548   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1549   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1550   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1551   print_signal_handler(st, SIGTRAP, buf, buflen);
1552   // We also want to know if someone else adds a SIGDANGER handler because
1553   // that will interfere with OOM killling.
1554   print_signal_handler(st, SIGDANGER, buf, buflen);
1555 }
1556 
1557 static char saved_jvm_path[MAXPATHLEN] = {0};
1558 
1559 // Find the full path to the current module, libjvm.so.
1560 void os::jvm_path(char *buf, jint buflen) {
1561   // Error checking.
1562   if (buflen < MAXPATHLEN) {
1563     assert(false, "must use a large-enough buffer");
1564     buf[0] = '\0';
1565     return;
1566   }
1567   // Lazy resolve the path to current module.
1568   if (saved_jvm_path[0] != 0) {
1569     strcpy(buf, saved_jvm_path);
1570     return;
1571   }
1572 
1573   Dl_info dlinfo;
1574   int ret = dladdr(CAST_FROM_FN_PTR(void *, os::jvm_path), &dlinfo);
1575   assert(ret != 0, "cannot locate libjvm");
1576   char* rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1577   assert(rp != NULL, "error in realpath(): maybe the 'path' argument is too long?");
1578 
1579   if (Arguments::sun_java_launcher_is_altjvm()) {
1580     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1581     // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
1582     // If "/jre/lib/" appears at the right place in the string, then
1583     // assume we are installed in a JDK and we're done. Otherwise, check
1584     // for a JAVA_HOME environment variable and fix up the path so it
1585     // looks like libjvm.so is installed there (append a fake suffix
1586     // hotspot/libjvm.so).
1587     const char *p = buf + strlen(buf) - 1;
1588     for (int count = 0; p > buf && count < 4; ++count) {
1589       for (--p; p > buf && *p != '/'; --p)
1590         /* empty */ ;
1591     }
1592 
1593     if (strncmp(p, "/jre/lib/", 9) != 0) {
1594       // Look for JAVA_HOME in the environment.
1595       char* java_home_var = ::getenv("JAVA_HOME");
1596       if (java_home_var != NULL && java_home_var[0] != 0) {
1597         char* jrelib_p;
1598         int len;
1599 
1600         // Check the current module name "libjvm.so".
1601         p = strrchr(buf, '/');
1602         if (p == NULL) {
1603           return;
1604         }
1605         assert(strstr(p, "/libjvm") == p, "invalid library name");
1606 
1607         rp = os::Posix::realpath(java_home_var, buf, buflen);
1608         if (rp == NULL) {
1609           return;
1610         }
1611 
1612         // determine if this is a legacy image or modules image
1613         // modules image doesn't have "jre" subdirectory
1614         len = strlen(buf);
1615         assert(len < buflen, "Ran out of buffer room");
1616         jrelib_p = buf + len;
1617         snprintf(jrelib_p, buflen-len, "/jre/lib");
1618         if (0 != access(buf, F_OK)) {
1619           snprintf(jrelib_p, buflen-len, "/lib");
1620         }
1621 
1622         if (0 == access(buf, F_OK)) {
1623           // Use current module name "libjvm.so"
1624           len = strlen(buf);
1625           snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
1626         } else {
1627           // Go back to path of .so
1628           rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1629           if (rp == NULL) {
1630             return;
1631           }
1632         }
1633       }
1634     }
1635   }
1636 
1637   strncpy(saved_jvm_path, buf, sizeof(saved_jvm_path));
1638   saved_jvm_path[sizeof(saved_jvm_path) - 1] = '\0';
1639 }
1640 
1641 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1642   // no prefix required, not even "_"
1643 }
1644 
1645 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1646   // no suffix required
1647 }
1648 
1649 ////////////////////////////////////////////////////////////////////////////////
1650 // sun.misc.Signal support
1651 
1652 static volatile jint sigint_count = 0;
1653 
1654 static void
1655 UserHandler(int sig, void *siginfo, void *context) {
1656   // 4511530 - sem_post is serialized and handled by the manager thread. When
1657   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1658   // don't want to flood the manager thread with sem_post requests.
1659   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1660     return;
1661 
1662   // Ctrl-C is pressed during error reporting, likely because the error
1663   // handler fails to abort. Let VM die immediately.
1664   if (sig == SIGINT && VMError::is_error_reported()) {
1665     os::die();
1666   }
1667 
1668   os::signal_notify(sig);
1669 }
1670 
1671 void* os::user_handler() {
1672   return CAST_FROM_FN_PTR(void*, UserHandler);
1673 }
1674 
1675 extern "C" {
1676   typedef void (*sa_handler_t)(int);
1677   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1678 }
1679 
1680 void* os::signal(int signal_number, void* handler) {
1681   struct sigaction sigAct, oldSigAct;
1682 
1683   sigfillset(&(sigAct.sa_mask));
1684 
1685   // Do not block out synchronous signals in the signal handler.
1686   // Blocking synchronous signals only makes sense if you can really
1687   // be sure that those signals won't happen during signal handling,
1688   // when the blocking applies. Normal signal handlers are lean and
1689   // do not cause signals. But our signal handlers tend to be "risky"
1690   // - secondary SIGSEGV, SIGILL, SIGBUS' may and do happen.
1691   // On AIX, PASE there was a case where a SIGSEGV happened, followed
1692   // by a SIGILL, which was blocked due to the signal mask. The process
1693   // just hung forever. Better to crash from a secondary signal than to hang.
1694   sigdelset(&(sigAct.sa_mask), SIGSEGV);
1695   sigdelset(&(sigAct.sa_mask), SIGBUS);
1696   sigdelset(&(sigAct.sa_mask), SIGILL);
1697   sigdelset(&(sigAct.sa_mask), SIGFPE);
1698   sigdelset(&(sigAct.sa_mask), SIGTRAP);
1699 
1700   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1701 
1702   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1703 
1704   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1705     // -1 means registration failed
1706     return (void *)-1;
1707   }
1708 
1709   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1710 }
1711 
1712 void os::signal_raise(int signal_number) {
1713   ::raise(signal_number);
1714 }
1715 
1716 //
1717 // The following code is moved from os.cpp for making this
1718 // code platform specific, which it is by its very nature.
1719 //
1720 
1721 // Will be modified when max signal is changed to be dynamic
1722 int os::sigexitnum_pd() {
1723   return NSIG;
1724 }
1725 
1726 // a counter for each possible signal value
1727 static volatile jint pending_signals[NSIG+1] = { 0 };
1728 
1729 // Wrapper functions for: sem_init(), sem_post(), sem_wait()
1730 // On AIX, we use sem_init(), sem_post(), sem_wait()
1731 // On Pase, we need to use msem_lock() and msem_unlock(), because Posix Semaphores
1732 // do not seem to work at all on PASE (unimplemented, will cause SIGILL).
1733 // Note that just using msem_.. APIs for both PASE and AIX is not an option either, as
1734 // on AIX, msem_..() calls are suspected of causing problems.
1735 static sem_t sig_sem;
1736 static msemaphore* p_sig_msem = 0;
1737 
1738 static void local_sem_init() {
1739   if (os::Aix::on_aix()) {
1740     int rc = ::sem_init(&sig_sem, 0, 0);
1741     guarantee(rc != -1, "sem_init failed");
1742   } else {
1743     // Memory semaphores must live in shared mem.
1744     guarantee0(p_sig_msem == NULL);
1745     p_sig_msem = (msemaphore*)os::reserve_memory(sizeof(msemaphore), NULL);
1746     guarantee(p_sig_msem, "Cannot allocate memory for memory semaphore");
1747     guarantee(::msem_init(p_sig_msem, 0) == p_sig_msem, "msem_init failed");
1748   }
1749 }
1750 
1751 static void local_sem_post() {
1752   static bool warn_only_once = false;
1753   if (os::Aix::on_aix()) {
1754     int rc = ::sem_post(&sig_sem);
1755     if (rc == -1 && !warn_only_once) {
1756       trcVerbose("sem_post failed (errno = %d, %s)", errno, os::errno_name(errno));
1757       warn_only_once = true;
1758     }
1759   } else {
1760     guarantee0(p_sig_msem != NULL);
1761     int rc = ::msem_unlock(p_sig_msem, 0);
1762     if (rc == -1 && !warn_only_once) {
1763       trcVerbose("msem_unlock failed (errno = %d, %s)", errno, os::errno_name(errno));
1764       warn_only_once = true;
1765     }
1766   }
1767 }
1768 
1769 static void local_sem_wait() {
1770   static bool warn_only_once = false;
1771   if (os::Aix::on_aix()) {
1772     int rc = ::sem_wait(&sig_sem);
1773     if (rc == -1 && !warn_only_once) {
1774       trcVerbose("sem_wait failed (errno = %d, %s)", errno, os::errno_name(errno));
1775       warn_only_once = true;
1776     }
1777   } else {
1778     guarantee0(p_sig_msem != NULL); // must init before use
1779     int rc = ::msem_lock(p_sig_msem, 0);
1780     if (rc == -1 && !warn_only_once) {
1781       trcVerbose("msem_lock failed (errno = %d, %s)", errno, os::errno_name(errno));
1782       warn_only_once = true;
1783     }
1784   }
1785 }
1786 
1787 void os::signal_init_pd() {
1788   // Initialize signal structures
1789   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
1790 
1791   // Initialize signal semaphore
1792   local_sem_init();
1793 }
1794 
1795 void os::signal_notify(int sig) {
1796   Atomic::inc(&pending_signals[sig]);
1797   local_sem_post();
1798 }
1799 
1800 static int check_pending_signals() {
1801   Atomic::store(0, &sigint_count);
1802   for (;;) {
1803     for (int i = 0; i < NSIG + 1; i++) {
1804       jint n = pending_signals[i];
1805       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
1806         return i;
1807       }
1808     }
1809     JavaThread *thread = JavaThread::current();
1810     ThreadBlockInVM tbivm(thread);
1811 
1812     bool threadIsSuspended;
1813     do {
1814       thread->set_suspend_equivalent();
1815       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1816 
1817       local_sem_wait();
1818 
1819       // were we externally suspended while we were waiting?
1820       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
1821       if (threadIsSuspended) {
1822         //
1823         // The semaphore has been incremented, but while we were waiting
1824         // another thread suspended us. We don't want to continue running
1825         // while suspended because that would surprise the thread that
1826         // suspended us.
1827         //
1828 
1829         local_sem_post();
1830 
1831         thread->java_suspend_self();
1832       }
1833     } while (threadIsSuspended);
1834   }
1835 }
1836 
1837 int os::signal_wait() {
1838   return check_pending_signals();
1839 }
1840 
1841 ////////////////////////////////////////////////////////////////////////////////
1842 // Virtual Memory
1843 
1844 // We need to keep small simple bookkeeping for os::reserve_memory and friends.
1845 
1846 #define VMEM_MAPPED  1
1847 #define VMEM_SHMATED 2
1848 
1849 struct vmembk_t {
1850   int type;         // 1 - mmap, 2 - shmat
1851   char* addr;
1852   size_t size;      // Real size, may be larger than usersize.
1853   size_t pagesize;  // page size of area
1854   vmembk_t* next;
1855 
1856   bool contains_addr(char* p) const {
1857     return p >= addr && p < (addr + size);
1858   }
1859 
1860   bool contains_range(char* p, size_t s) const {
1861     return contains_addr(p) && contains_addr(p + s - 1);
1862   }
1863 
1864   void print_on(outputStream* os) const {
1865     os->print("[" PTR_FORMAT " - " PTR_FORMAT "] (" UINTX_FORMAT
1866       " bytes, %d %s pages), %s",
1867       addr, addr + size - 1, size, size / pagesize, describe_pagesize(pagesize),
1868       (type == VMEM_SHMATED ? "shmat" : "mmap")
1869     );
1870   }
1871 
1872   // Check that range is a sub range of memory block (or equal to memory block);
1873   // also check that range is fully page aligned to the page size if the block.
1874   void assert_is_valid_subrange(char* p, size_t s) const {
1875     if (!contains_range(p, s)) {
1876       trcVerbose("[" PTR_FORMAT " - " PTR_FORMAT "] is not a sub "
1877               "range of [" PTR_FORMAT " - " PTR_FORMAT "].",
1878               p, p + s, addr, addr + size);
1879       guarantee0(false);
1880     }
1881     if (!is_aligned_to(p, pagesize) || !is_aligned_to(p + s, pagesize)) {
1882       trcVerbose("range [" PTR_FORMAT " - " PTR_FORMAT "] is not"
1883               " aligned to pagesize (%lu)", p, p + s, (unsigned long) pagesize);
1884       guarantee0(false);
1885     }
1886   }
1887 };
1888 
1889 static struct {
1890   vmembk_t* first;
1891   MiscUtils::CritSect cs;
1892 } vmem;
1893 
1894 static void vmembk_add(char* addr, size_t size, size_t pagesize, int type) {
1895   vmembk_t* p = (vmembk_t*) ::malloc(sizeof(vmembk_t));
1896   assert0(p);
1897   if (p) {
1898     MiscUtils::AutoCritSect lck(&vmem.cs);
1899     p->addr = addr; p->size = size;
1900     p->pagesize = pagesize;
1901     p->type = type;
1902     p->next = vmem.first;
1903     vmem.first = p;
1904   }
1905 }
1906 
1907 static vmembk_t* vmembk_find(char* addr) {
1908   MiscUtils::AutoCritSect lck(&vmem.cs);
1909   for (vmembk_t* p = vmem.first; p; p = p->next) {
1910     if (p->addr <= addr && (p->addr + p->size) > addr) {
1911       return p;
1912     }
1913   }
1914   return NULL;
1915 }
1916 
1917 static void vmembk_remove(vmembk_t* p0) {
1918   MiscUtils::AutoCritSect lck(&vmem.cs);
1919   assert0(p0);
1920   assert0(vmem.first); // List should not be empty.
1921   for (vmembk_t** pp = &(vmem.first); *pp; pp = &((*pp)->next)) {
1922     if (*pp == p0) {
1923       *pp = p0->next;
1924       ::free(p0);
1925       return;
1926     }
1927   }
1928   assert0(false); // Not found?
1929 }
1930 
1931 static void vmembk_print_on(outputStream* os) {
1932   MiscUtils::AutoCritSect lck(&vmem.cs);
1933   for (vmembk_t* vmi = vmem.first; vmi; vmi = vmi->next) {
1934     vmi->print_on(os);
1935     os->cr();
1936   }
1937 }
1938 
1939 // Reserve and attach a section of System V memory.
1940 // If <requested_addr> is not NULL, function will attempt to attach the memory at the given
1941 // address. Failing that, it will attach the memory anywhere.
1942 // If <requested_addr> is NULL, function will attach the memory anywhere.
1943 //
1944 // <alignment_hint> is being ignored by this function. It is very probable however that the
1945 // alignment requirements are met anyway, because shmat() attaches at 256M boundaries.
1946 // Should this be not enogh, we can put more work into it.
1947 static char* reserve_shmated_memory (
1948   size_t bytes,
1949   char* requested_addr,
1950   size_t alignment_hint) {
1951 
1952   trcVerbose("reserve_shmated_memory " UINTX_FORMAT " bytes, wishaddress "
1953     PTR_FORMAT ", alignment_hint " UINTX_FORMAT "...",
1954     bytes, requested_addr, alignment_hint);
1955 
1956   // Either give me wish address or wish alignment but not both.
1957   assert0(!(requested_addr != NULL && alignment_hint != 0));
1958 
1959   // We must prevent anyone from attaching too close to the
1960   // BRK because that may cause malloc OOM.
1961   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
1962     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
1963       "Will attach anywhere.", requested_addr);
1964     // Act like the OS refused to attach there.
1965     requested_addr = NULL;
1966   }
1967 
1968   // For old AS/400's (V5R4 and older) we should not even be here - System V shared memory is not
1969   // really supported (max size 4GB), so reserve_mmapped_memory should have been used instead.
1970   if (os::Aix::on_pase_V5R4_or_older()) {
1971     ShouldNotReachHere();
1972   }
1973 
1974   // Align size of shm up to 64K to avoid errors if we later try to change the page size.
1975   const size_t size = align_up(bytes, 64*K);
1976 
1977   // Reserve the shared segment.
1978   int shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | S_IRUSR | S_IWUSR);
1979   if (shmid == -1) {
1980     trcVerbose("shmget(.., " UINTX_FORMAT ", ..) failed (errno: %d).", size, errno);
1981     return NULL;
1982   }
1983 
1984   // Important note:
1985   // It is very important that we, upon leaving this function, do not leave a shm segment alive.
1986   // We must right after attaching it remove it from the system. System V shm segments are global and
1987   // survive the process.
1988   // So, from here on: Do not assert, do not return, until we have called shmctl(IPC_RMID) (A).
1989 
1990   struct shmid_ds shmbuf;
1991   memset(&shmbuf, 0, sizeof(shmbuf));
1992   shmbuf.shm_pagesize = 64*K;
1993   if (shmctl(shmid, SHM_PAGESIZE, &shmbuf) != 0) {
1994     trcVerbose("Failed to set page size (need " UINTX_FORMAT " 64K pages) - shmctl failed with %d.",
1995                size / (64*K), errno);
1996     // I want to know if this ever happens.
1997     assert(false, "failed to set page size for shmat");
1998   }
1999 
2000   // Now attach the shared segment.
2001   // Note that I attach with SHM_RND - which means that the requested address is rounded down, if
2002   // needed, to the next lowest segment boundary. Otherwise the attach would fail if the address
2003   // were not a segment boundary.
2004   char* const addr = (char*) shmat(shmid, requested_addr, SHM_RND);
2005   const int errno_shmat = errno;
2006 
2007   // (A) Right after shmat and before handing shmat errors delete the shm segment.
2008   if (::shmctl(shmid, IPC_RMID, NULL) == -1) {
2009     trcVerbose("shmctl(%u, IPC_RMID) failed (%d)\n", shmid, errno);
2010     assert(false, "failed to remove shared memory segment!");
2011   }
2012 
2013   // Handle shmat error. If we failed to attach, just return.
2014   if (addr == (char*)-1) {
2015     trcVerbose("Failed to attach segment at " PTR_FORMAT " (%d).", requested_addr, errno_shmat);
2016     return NULL;
2017   }
2018 
2019   // Just for info: query the real page size. In case setting the page size did not
2020   // work (see above), the system may have given us something other then 4K (LDR_CNTRL).
2021   const size_t real_pagesize = os::Aix::query_pagesize(addr);
2022   if (real_pagesize != shmbuf.shm_pagesize) {
2023     trcVerbose("pagesize is, surprisingly, %h.", real_pagesize);
2024   }
2025 
2026   if (addr) {
2027     trcVerbose("shm-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes, " UINTX_FORMAT " %s pages)",
2028       addr, addr + size - 1, size, size/real_pagesize, describe_pagesize(real_pagesize));
2029   } else {
2030     if (requested_addr != NULL) {
2031       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at with address " PTR_FORMAT ".", size, requested_addr);
2032     } else {
2033       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at any address.", size);
2034     }
2035   }
2036 
2037   // book-keeping
2038   vmembk_add(addr, size, real_pagesize, VMEM_SHMATED);
2039   assert0(is_aligned_to(addr, os::vm_page_size()));
2040 
2041   return addr;
2042 }
2043 
2044 static bool release_shmated_memory(char* addr, size_t size) {
2045 
2046   trcVerbose("release_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2047     addr, addr + size - 1);
2048 
2049   bool rc = false;
2050 
2051   // TODO: is there a way to verify shm size without doing bookkeeping?
2052   if (::shmdt(addr) != 0) {
2053     trcVerbose("error (%d).", errno);
2054   } else {
2055     trcVerbose("ok.");
2056     rc = true;
2057   }
2058   return rc;
2059 }
2060 
2061 static bool uncommit_shmated_memory(char* addr, size_t size) {
2062   trcVerbose("uncommit_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2063     addr, addr + size - 1);
2064 
2065   const bool rc = my_disclaim64(addr, size);
2066 
2067   if (!rc) {
2068     trcVerbose("my_disclaim64(" PTR_FORMAT ", " UINTX_FORMAT ") failed.\n", addr, size);
2069     return false;
2070   }
2071   return true;
2072 }
2073 
2074 ////////////////////////////////  mmap-based routines /////////////////////////////////
2075 
2076 // Reserve memory via mmap.
2077 // If <requested_addr> is given, an attempt is made to attach at the given address.
2078 // Failing that, memory is allocated at any address.
2079 // If <alignment_hint> is given and <requested_addr> is NULL, an attempt is made to
2080 // allocate at an address aligned with the given alignment. Failing that, memory
2081 // is aligned anywhere.
2082 static char* reserve_mmaped_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2083   trcVerbose("reserve_mmaped_memory " UINTX_FORMAT " bytes, wishaddress " PTR_FORMAT ", "
2084     "alignment_hint " UINTX_FORMAT "...",
2085     bytes, requested_addr, alignment_hint);
2086 
2087   // If a wish address is given, but not aligned to 4K page boundary, mmap will fail.
2088   if (requested_addr && !is_aligned_to(requested_addr, os::vm_page_size()) != 0) {
2089     trcVerbose("Wish address " PTR_FORMAT " not aligned to page boundary.", requested_addr);
2090     return NULL;
2091   }
2092 
2093   // We must prevent anyone from attaching too close to the
2094   // BRK because that may cause malloc OOM.
2095   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
2096     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
2097       "Will attach anywhere.", requested_addr);
2098     // Act like the OS refused to attach there.
2099     requested_addr = NULL;
2100   }
2101 
2102   // Specify one or the other but not both.
2103   assert0(!(requested_addr != NULL && alignment_hint > 0));
2104 
2105   // In 64K mode, we claim the global page size (os::vm_page_size())
2106   // is 64K. This is one of the few points where that illusion may
2107   // break, because mmap() will always return memory aligned to 4K. So
2108   // we must ensure we only ever return memory aligned to 64k.
2109   if (alignment_hint) {
2110     alignment_hint = lcm(alignment_hint, os::vm_page_size());
2111   } else {
2112     alignment_hint = os::vm_page_size();
2113   }
2114 
2115   // Size shall always be a multiple of os::vm_page_size (esp. in 64K mode).
2116   const size_t size = align_up(bytes, os::vm_page_size());
2117 
2118   // alignment: Allocate memory large enough to include an aligned range of the right size and
2119   // cut off the leading and trailing waste pages.
2120   assert0(alignment_hint != 0 && is_aligned_to(alignment_hint, os::vm_page_size())); // see above
2121   const size_t extra_size = size + alignment_hint;
2122 
2123   // Note: MAP_SHARED (instead of MAP_PRIVATE) needed to be able to
2124   // later use msync(MS_INVALIDATE) (see os::uncommit_memory).
2125   int flags = MAP_ANONYMOUS | MAP_SHARED;
2126 
2127   // MAP_FIXED is needed to enforce requested_addr - manpage is vague about what
2128   // it means if wishaddress is given but MAP_FIXED is not set.
2129   //
2130   // Important! Behaviour differs depending on whether SPEC1170 mode is active or not.
2131   // SPEC1170 mode active: behaviour like POSIX, MAP_FIXED will clobber existing mappings.
2132   // SPEC1170 mode not active: behaviour, unlike POSIX, is that no existing mappings will
2133   // get clobbered.
2134   if (requested_addr != NULL) {
2135     if (!os::Aix::xpg_sus_mode()) {  // not SPEC1170 Behaviour
2136       flags |= MAP_FIXED;
2137     }
2138   }
2139 
2140   char* addr = (char*)::mmap(requested_addr, extra_size,
2141       PROT_READ|PROT_WRITE|PROT_EXEC, flags, -1, 0);
2142 
2143   if (addr == MAP_FAILED) {
2144     trcVerbose("mmap(" PTR_FORMAT ", " UINTX_FORMAT ", ..) failed (%d)", requested_addr, size, errno);
2145     return NULL;
2146   }
2147 
2148   // Handle alignment.
2149   char* const addr_aligned = align_up(addr, alignment_hint);
2150   const size_t waste_pre = addr_aligned - addr;
2151   char* const addr_aligned_end = addr_aligned + size;
2152   const size_t waste_post = extra_size - waste_pre - size;
2153   if (waste_pre > 0) {
2154     ::munmap(addr, waste_pre);
2155   }
2156   if (waste_post > 0) {
2157     ::munmap(addr_aligned_end, waste_post);
2158   }
2159   addr = addr_aligned;
2160 
2161   if (addr) {
2162     trcVerbose("mmap-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes)",
2163       addr, addr + bytes, bytes);
2164   } else {
2165     if (requested_addr != NULL) {
2166       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at wish address " PTR_FORMAT ".", bytes, requested_addr);
2167     } else {
2168       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at any address.", bytes);
2169     }
2170   }
2171 
2172   // bookkeeping
2173   vmembk_add(addr, size, 4*K, VMEM_MAPPED);
2174 
2175   // Test alignment, see above.
2176   assert0(is_aligned_to(addr, os::vm_page_size()));
2177 
2178   return addr;
2179 }
2180 
2181 static bool release_mmaped_memory(char* addr, size_t size) {
2182   assert0(is_aligned_to(addr, os::vm_page_size()));
2183   assert0(is_aligned_to(size, os::vm_page_size()));
2184 
2185   trcVerbose("release_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2186     addr, addr + size - 1);
2187   bool rc = false;
2188 
2189   if (::munmap(addr, size) != 0) {
2190     trcVerbose("failed (%d)\n", errno);
2191     rc = false;
2192   } else {
2193     trcVerbose("ok.");
2194     rc = true;
2195   }
2196 
2197   return rc;
2198 }
2199 
2200 static bool uncommit_mmaped_memory(char* addr, size_t size) {
2201 
2202   assert0(is_aligned_to(addr, os::vm_page_size()));
2203   assert0(is_aligned_to(size, os::vm_page_size()));
2204 
2205   trcVerbose("uncommit_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2206     addr, addr + size - 1);
2207   bool rc = false;
2208 
2209   // Uncommit mmap memory with msync MS_INVALIDATE.
2210   if (::msync(addr, size, MS_INVALIDATE) != 0) {
2211     trcVerbose("failed (%d)\n", errno);
2212     rc = false;
2213   } else {
2214     trcVerbose("ok.");
2215     rc = true;
2216   }
2217 
2218   return rc;
2219 }
2220 
2221 int os::vm_page_size() {
2222   // Seems redundant as all get out.
2223   assert(os::Aix::page_size() != -1, "must call os::init");
2224   return os::Aix::page_size();
2225 }
2226 
2227 // Aix allocates memory by pages.
2228 int os::vm_allocation_granularity() {
2229   assert(os::Aix::page_size() != -1, "must call os::init");
2230   return os::Aix::page_size();
2231 }
2232 
2233 #ifdef PRODUCT
2234 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2235                                     int err) {
2236   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2237           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2238           os::errno_name(err), err);
2239 }
2240 #endif
2241 
2242 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2243                                   const char* mesg) {
2244   assert(mesg != NULL, "mesg must be specified");
2245   if (!pd_commit_memory(addr, size, exec)) {
2246     // Add extra info in product mode for vm_exit_out_of_memory():
2247     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2248     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2249   }
2250 }
2251 
2252 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2253 
2254   assert(is_aligned_to(addr, os::vm_page_size()),
2255     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2256     p2i(addr), os::vm_page_size());
2257   assert(is_aligned_to(size, os::vm_page_size()),
2258     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2259     size, os::vm_page_size());
2260 
2261   vmembk_t* const vmi = vmembk_find(addr);
2262   guarantee0(vmi);
2263   vmi->assert_is_valid_subrange(addr, size);
2264 
2265   trcVerbose("commit_memory [" PTR_FORMAT " - " PTR_FORMAT "].", addr, addr + size - 1);
2266 
2267   if (UseExplicitCommit) {
2268     // AIX commits memory on touch. So, touch all pages to be committed.
2269     for (char* p = addr; p < (addr + size); p += 4*K) {
2270       *p = '\0';
2271     }
2272   }
2273 
2274   return true;
2275 }
2276 
2277 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, bool exec) {
2278   return pd_commit_memory(addr, size, exec);
2279 }
2280 
2281 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2282                                   size_t alignment_hint, bool exec,
2283                                   const char* mesg) {
2284   // Alignment_hint is ignored on this OS.
2285   pd_commit_memory_or_exit(addr, size, exec, mesg);
2286 }
2287 
2288 bool os::pd_uncommit_memory(char* addr, size_t size) {
2289   assert(is_aligned_to(addr, os::vm_page_size()),
2290     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2291     p2i(addr), os::vm_page_size());
2292   assert(is_aligned_to(size, os::vm_page_size()),
2293     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2294     size, os::vm_page_size());
2295 
2296   // Dynamically do different things for mmap/shmat.
2297   const vmembk_t* const vmi = vmembk_find(addr);
2298   guarantee0(vmi);
2299   vmi->assert_is_valid_subrange(addr, size);
2300 
2301   if (vmi->type == VMEM_SHMATED) {
2302     return uncommit_shmated_memory(addr, size);
2303   } else {
2304     return uncommit_mmaped_memory(addr, size);
2305   }
2306 }
2307 
2308 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2309   // Do not call this; no need to commit stack pages on AIX.
2310   ShouldNotReachHere();
2311   return true;
2312 }
2313 
2314 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2315   // Do not call this; no need to commit stack pages on AIX.
2316   ShouldNotReachHere();
2317   return true;
2318 }
2319 
2320 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2321 }
2322 
2323 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2324 }
2325 
2326 void os::numa_make_global(char *addr, size_t bytes) {
2327 }
2328 
2329 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2330 }
2331 
2332 bool os::numa_topology_changed() {
2333   return false;
2334 }
2335 
2336 size_t os::numa_get_groups_num() {
2337   return 1;
2338 }
2339 
2340 int os::numa_get_group_id() {
2341   return 0;
2342 }
2343 
2344 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2345   if (size > 0) {
2346     ids[0] = 0;
2347     return 1;
2348   }
2349   return 0;
2350 }
2351 
2352 bool os::get_page_info(char *start, page_info* info) {
2353   return false;
2354 }
2355 
2356 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2357   return end;
2358 }
2359 
2360 // Reserves and attaches a shared memory segment.
2361 // Will assert if a wish address is given and could not be obtained.
2362 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2363 
2364   // All other Unices do a mmap(MAP_FIXED) if the addr is given,
2365   // thereby clobbering old mappings at that place. That is probably
2366   // not intended, never used and almost certainly an error were it
2367   // ever be used this way (to try attaching at a specified address
2368   // without clobbering old mappings an alternate API exists,
2369   // os::attempt_reserve_memory_at()).
2370   // Instead of mimicking the dangerous coding of the other platforms, here I
2371   // just ignore the request address (release) or assert(debug).
2372   assert0(requested_addr == NULL);
2373 
2374   // Always round to os::vm_page_size(), which may be larger than 4K.
2375   bytes = align_up(bytes, os::vm_page_size());
2376   const size_t alignment_hint0 =
2377     alignment_hint ? align_up(alignment_hint, os::vm_page_size()) : 0;
2378 
2379   // In 4K mode always use mmap.
2380   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2381   if (os::vm_page_size() == 4*K) {
2382     return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2383   } else {
2384     if (bytes >= Use64KPagesThreshold) {
2385       return reserve_shmated_memory(bytes, requested_addr, alignment_hint);
2386     } else {
2387       return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2388     }
2389   }
2390 }
2391 
2392 bool os::pd_release_memory(char* addr, size_t size) {
2393 
2394   // Dynamically do different things for mmap/shmat.
2395   vmembk_t* const vmi = vmembk_find(addr);
2396   guarantee0(vmi);
2397 
2398   // Always round to os::vm_page_size(), which may be larger than 4K.
2399   size = align_up(size, os::vm_page_size());
2400   addr = align_up(addr, os::vm_page_size());
2401 
2402   bool rc = false;
2403   bool remove_bookkeeping = false;
2404   if (vmi->type == VMEM_SHMATED) {
2405     // For shmatted memory, we do:
2406     // - If user wants to release the whole range, release the memory (shmdt).
2407     // - If user only wants to release a partial range, uncommit (disclaim) that
2408     //   range. That way, at least, we do not use memory anymore (bust still page
2409     //   table space).
2410     vmi->assert_is_valid_subrange(addr, size);
2411     if (addr == vmi->addr && size == vmi->size) {
2412       rc = release_shmated_memory(addr, size);
2413       remove_bookkeeping = true;
2414     } else {
2415       rc = uncommit_shmated_memory(addr, size);
2416     }
2417   } else {
2418     // User may unmap partial regions but region has to be fully contained.
2419 #ifdef ASSERT
2420     vmi->assert_is_valid_subrange(addr, size);
2421 #endif
2422     rc = release_mmaped_memory(addr, size);
2423     remove_bookkeeping = true;
2424   }
2425 
2426   // update bookkeeping
2427   if (rc && remove_bookkeeping) {
2428     vmembk_remove(vmi);
2429   }
2430 
2431   return rc;
2432 }
2433 
2434 static bool checked_mprotect(char* addr, size_t size, int prot) {
2435 
2436   // Little problem here: if SPEC1170 behaviour is off, mprotect() on AIX will
2437   // not tell me if protection failed when trying to protect an un-protectable range.
2438   //
2439   // This means if the memory was allocated using shmget/shmat, protection wont work
2440   // but mprotect will still return 0:
2441   //
2442   // See http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/mprotect.htm
2443 
2444   bool rc = ::mprotect(addr, size, prot) == 0 ? true : false;
2445 
2446   if (!rc) {
2447     const char* const s_errno = os::errno_name(errno);
2448     warning("mprotect(" PTR_FORMAT "-" PTR_FORMAT ", 0x%X) failed (%s).", addr, addr + size, prot, s_errno);
2449     return false;
2450   }
2451 
2452   // mprotect success check
2453   //
2454   // Mprotect said it changed the protection but can I believe it?
2455   //
2456   // To be sure I need to check the protection afterwards. Try to
2457   // read from protected memory and check whether that causes a segfault.
2458   //
2459   if (!os::Aix::xpg_sus_mode()) {
2460 
2461     if (CanUseSafeFetch32()) {
2462 
2463       const bool read_protected =
2464         (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2465          SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2466 
2467       if (prot & PROT_READ) {
2468         rc = !read_protected;
2469       } else {
2470         rc = read_protected;
2471       }
2472 
2473       if (!rc) {
2474         if (os::Aix::on_pase()) {
2475           // There is an issue on older PASE systems where mprotect() will return success but the
2476           // memory will not be protected.
2477           // This has nothing to do with the problem of using mproect() on SPEC1170 incompatible
2478           // machines; we only see it rarely, when using mprotect() to protect the guard page of
2479           // a stack. It is an OS error.
2480           //
2481           // A valid strategy is just to try again. This usually works. :-/
2482 
2483           ::usleep(1000);
2484           if (::mprotect(addr, size, prot) == 0) {
2485             const bool read_protected_2 =
2486               (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2487               SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2488             rc = true;
2489           }
2490         }
2491       }
2492     }
2493   }
2494 
2495   assert(rc == true, "mprotect failed.");
2496 
2497   return rc;
2498 }
2499 
2500 // Set protections specified
2501 bool os::protect_memory(char* addr, size_t size, ProtType prot, bool is_committed) {
2502   unsigned int p = 0;
2503   switch (prot) {
2504   case MEM_PROT_NONE: p = PROT_NONE; break;
2505   case MEM_PROT_READ: p = PROT_READ; break;
2506   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2507   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2508   default:
2509     ShouldNotReachHere();
2510   }
2511   // is_committed is unused.
2512   return checked_mprotect(addr, size, p);
2513 }
2514 
2515 bool os::guard_memory(char* addr, size_t size) {
2516   return checked_mprotect(addr, size, PROT_NONE);
2517 }
2518 
2519 bool os::unguard_memory(char* addr, size_t size) {
2520   return checked_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
2521 }
2522 
2523 // Large page support
2524 
2525 static size_t _large_page_size = 0;
2526 
2527 // Enable large page support if OS allows that.
2528 void os::large_page_init() {
2529   return; // Nothing to do. See query_multipage_support and friends.
2530 }
2531 
2532 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2533   // reserve_memory_special() is used to allocate large paged memory. On AIX, we implement
2534   // 64k paged memory reservation using the normal memory allocation paths (os::reserve_memory()),
2535   // so this is not needed.
2536   assert(false, "should not be called on AIX");
2537   return NULL;
2538 }
2539 
2540 bool os::release_memory_special(char* base, size_t bytes) {
2541   // Detaching the SHM segment will also delete it, see reserve_memory_special().
2542   Unimplemented();
2543   return false;
2544 }
2545 
2546 size_t os::large_page_size() {
2547   return _large_page_size;
2548 }
2549 
2550 bool os::can_commit_large_page_memory() {
2551   // Does not matter, we do not support huge pages.
2552   return false;
2553 }
2554 
2555 bool os::can_execute_large_page_memory() {
2556   // Does not matter, we do not support huge pages.
2557   return false;
2558 }
2559 
2560 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
2561   assert(file_desc >= 0, "file_desc is not valid");
2562   char* result = NULL;
2563 
2564   // Always round to os::vm_page_size(), which may be larger than 4K.
2565   bytes = align_up(bytes, os::vm_page_size());
2566   result = reserve_mmaped_memory(bytes, requested_addr, 0);
2567 
2568   if (result != NULL) {
2569     if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
2570       vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
2571     }
2572   }
2573   return result;
2574 }
2575 
2576 // Reserve memory at an arbitrary address, only if that area is
2577 // available (and not reserved for something else).
2578 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2579   char* addr = NULL;
2580 
2581   // Always round to os::vm_page_size(), which may be larger than 4K.
2582   bytes = align_up(bytes, os::vm_page_size());
2583 
2584   // In 4K mode always use mmap.
2585   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2586   if (os::vm_page_size() == 4*K) {
2587     return reserve_mmaped_memory(bytes, requested_addr, 0);
2588   } else {
2589     if (bytes >= Use64KPagesThreshold) {
2590       return reserve_shmated_memory(bytes, requested_addr, 0);
2591     } else {
2592       return reserve_mmaped_memory(bytes, requested_addr, 0);
2593     }
2594   }
2595 
2596   return addr;
2597 }
2598 
2599 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2600   return ::read(fd, buf, nBytes);
2601 }
2602 
2603 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
2604   return ::pread(fd, buf, nBytes, offset);
2605 }
2606 
2607 void os::naked_short_sleep(jlong ms) {
2608   struct timespec req;
2609 
2610   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2611   req.tv_sec = 0;
2612   if (ms > 0) {
2613     req.tv_nsec = (ms % 1000) * 1000000;
2614   }
2615   else {
2616     req.tv_nsec = 1;
2617   }
2618 
2619   nanosleep(&req, NULL);
2620 
2621   return;
2622 }
2623 
2624 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2625 void os::infinite_sleep() {
2626   while (true) {    // sleep forever ...
2627     ::sleep(100);   // ... 100 seconds at a time
2628   }
2629 }
2630 
2631 // Used to convert frequent JVM_Yield() to nops
2632 bool os::dont_yield() {
2633   return DontYieldALot;
2634 }
2635 
2636 void os::naked_yield() {
2637   sched_yield();
2638 }
2639 
2640 ////////////////////////////////////////////////////////////////////////////////
2641 // thread priority support
2642 
2643 // From AIX manpage to pthread_setschedparam
2644 // (see: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?
2645 //    topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_setschedparam.htm):
2646 //
2647 // "If schedpolicy is SCHED_OTHER, then sched_priority must be in the
2648 // range from 40 to 80, where 40 is the least favored priority and 80
2649 // is the most favored."
2650 //
2651 // (Actually, I doubt this even has an impact on AIX, as we do kernel
2652 // scheduling there; however, this still leaves iSeries.)
2653 //
2654 // We use the same values for AIX and PASE.
2655 int os::java_to_os_priority[CriticalPriority + 1] = {
2656   54,             // 0 Entry should never be used
2657 
2658   55,             // 1 MinPriority
2659   55,             // 2
2660   56,             // 3
2661 
2662   56,             // 4
2663   57,             // 5 NormPriority
2664   57,             // 6
2665 
2666   58,             // 7
2667   58,             // 8
2668   59,             // 9 NearMaxPriority
2669 
2670   60,             // 10 MaxPriority
2671 
2672   60              // 11 CriticalPriority
2673 };
2674 
2675 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2676   if (!UseThreadPriorities) return OS_OK;
2677   pthread_t thr = thread->osthread()->pthread_id();
2678   int policy = SCHED_OTHER;
2679   struct sched_param param;
2680   param.sched_priority = newpri;
2681   int ret = pthread_setschedparam(thr, policy, &param);
2682 
2683   if (ret != 0) {
2684     trcVerbose("Could not change priority for thread %d to %d (error %d, %s)",
2685         (int)thr, newpri, ret, os::errno_name(ret));
2686   }
2687   return (ret == 0) ? OS_OK : OS_ERR;
2688 }
2689 
2690 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2691   if (!UseThreadPriorities) {
2692     *priority_ptr = java_to_os_priority[NormPriority];
2693     return OS_OK;
2694   }
2695   pthread_t thr = thread->osthread()->pthread_id();
2696   int policy = SCHED_OTHER;
2697   struct sched_param param;
2698   int ret = pthread_getschedparam(thr, &policy, &param);
2699   *priority_ptr = param.sched_priority;
2700 
2701   return (ret == 0) ? OS_OK : OS_ERR;
2702 }
2703 
2704 // Hint to the underlying OS that a task switch would not be good.
2705 // Void return because it's a hint and can fail.
2706 void os::hint_no_preempt() {}
2707 
2708 ////////////////////////////////////////////////////////////////////////////////
2709 // suspend/resume support
2710 
2711 //  The low-level signal-based suspend/resume support is a remnant from the
2712 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2713 //  within hotspot. Currently used by JFR's OSThreadSampler
2714 //
2715 //  The remaining code is greatly simplified from the more general suspension
2716 //  code that used to be used.
2717 //
2718 //  The protocol is quite simple:
2719 //  - suspend:
2720 //      - sends a signal to the target thread
2721 //      - polls the suspend state of the osthread using a yield loop
2722 //      - target thread signal handler (SR_handler) sets suspend state
2723 //        and blocks in sigsuspend until continued
2724 //  - resume:
2725 //      - sets target osthread state to continue
2726 //      - sends signal to end the sigsuspend loop in the SR_handler
2727 //
2728 //  Note that the SR_lock plays no role in this suspend/resume protocol,
2729 //  but is checked for NULL in SR_handler as a thread termination indicator.
2730 //  The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
2731 //
2732 //  Note that resume_clear_context() and suspend_save_context() are needed
2733 //  by SR_handler(), so that fetch_frame_from_ucontext() works,
2734 //  which in part is used by:
2735 //    - Forte Analyzer: AsyncGetCallTrace()
2736 //    - StackBanging: get_frame_at_stack_banging_point()
2737 
2738 static void resume_clear_context(OSThread *osthread) {
2739   osthread->set_ucontext(NULL);
2740   osthread->set_siginfo(NULL);
2741 }
2742 
2743 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2744   osthread->set_ucontext(context);
2745   osthread->set_siginfo(siginfo);
2746 }
2747 
2748 //
2749 // Handler function invoked when a thread's execution is suspended or
2750 // resumed. We have to be careful that only async-safe functions are
2751 // called here (Note: most pthread functions are not async safe and
2752 // should be avoided.)
2753 //
2754 // Note: sigwait() is a more natural fit than sigsuspend() from an
2755 // interface point of view, but sigwait() prevents the signal hander
2756 // from being run. libpthread would get very confused by not having
2757 // its signal handlers run and prevents sigwait()'s use with the
2758 // mutex granting granting signal.
2759 //
2760 // Currently only ever called on the VMThread and JavaThreads (PC sampling).
2761 //
2762 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2763   // Save and restore errno to avoid confusing native code with EINTR
2764   // after sigsuspend.
2765   int old_errno = errno;
2766 
2767   Thread* thread = Thread::current_or_null_safe();
2768   assert(thread != NULL, "Missing current thread in SR_handler");
2769 
2770   // On some systems we have seen signal delivery get "stuck" until the signal
2771   // mask is changed as part of thread termination. Check that the current thread
2772   // has not already terminated (via SR_lock()) - else the following assertion
2773   // will fail because the thread is no longer a JavaThread as the ~JavaThread
2774   // destructor has completed.
2775 
2776   if (thread->SR_lock() == NULL) {
2777     return;
2778   }
2779 
2780   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2781 
2782   OSThread* osthread = thread->osthread();
2783 
2784   os::SuspendResume::State current = osthread->sr.state();
2785   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2786     suspend_save_context(osthread, siginfo, context);
2787 
2788     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2789     os::SuspendResume::State state = osthread->sr.suspended();
2790     if (state == os::SuspendResume::SR_SUSPENDED) {
2791       sigset_t suspend_set;  // signals for sigsuspend()
2792 
2793       // get current set of blocked signals and unblock resume signal
2794       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2795       sigdelset(&suspend_set, SR_signum);
2796 
2797       // wait here until we are resumed
2798       while (1) {
2799         sigsuspend(&suspend_set);
2800 
2801         os::SuspendResume::State result = osthread->sr.running();
2802         if (result == os::SuspendResume::SR_RUNNING) {
2803           break;
2804         }
2805       }
2806 
2807     } else if (state == os::SuspendResume::SR_RUNNING) {
2808       // request was cancelled, continue
2809     } else {
2810       ShouldNotReachHere();
2811     }
2812 
2813     resume_clear_context(osthread);
2814   } else if (current == os::SuspendResume::SR_RUNNING) {
2815     // request was cancelled, continue
2816   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2817     // ignore
2818   } else {
2819     ShouldNotReachHere();
2820   }
2821 
2822   errno = old_errno;
2823 }
2824 
2825 static int SR_initialize() {
2826   struct sigaction act;
2827   char *s;
2828   // Get signal number to use for suspend/resume
2829   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2830     int sig = ::strtol(s, 0, 10);
2831     if (sig > MAX2(SIGSEGV, SIGBUS) &&  // See 4355769.
2832         sig < NSIG) {                   // Must be legal signal and fit into sigflags[].
2833       SR_signum = sig;
2834     } else {
2835       warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
2836               sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
2837     }
2838   }
2839 
2840   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2841         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2842 
2843   sigemptyset(&SR_sigset);
2844   sigaddset(&SR_sigset, SR_signum);
2845 
2846   // Set up signal handler for suspend/resume.
2847   act.sa_flags = SA_RESTART|SA_SIGINFO;
2848   act.sa_handler = (void (*)(int)) SR_handler;
2849 
2850   // SR_signum is blocked by default.
2851   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2852 
2853   if (sigaction(SR_signum, &act, 0) == -1) {
2854     return -1;
2855   }
2856 
2857   // Save signal flag
2858   os::Aix::set_our_sigflags(SR_signum, act.sa_flags);
2859   return 0;
2860 }
2861 
2862 static int SR_finalize() {
2863   return 0;
2864 }
2865 
2866 static int sr_notify(OSThread* osthread) {
2867   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2868   assert_status(status == 0, status, "pthread_kill");
2869   return status;
2870 }
2871 
2872 // "Randomly" selected value for how long we want to spin
2873 // before bailing out on suspending a thread, also how often
2874 // we send a signal to a thread we want to resume
2875 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2876 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2877 
2878 // returns true on success and false on error - really an error is fatal
2879 // but this seems the normal response to library errors
2880 static bool do_suspend(OSThread* osthread) {
2881   assert(osthread->sr.is_running(), "thread should be running");
2882   // mark as suspended and send signal
2883 
2884   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2885     // failed to switch, state wasn't running?
2886     ShouldNotReachHere();
2887     return false;
2888   }
2889 
2890   if (sr_notify(osthread) != 0) {
2891     // try to cancel, switch to running
2892 
2893     os::SuspendResume::State result = osthread->sr.cancel_suspend();
2894     if (result == os::SuspendResume::SR_RUNNING) {
2895       // cancelled
2896       return false;
2897     } else if (result == os::SuspendResume::SR_SUSPENDED) {
2898       // somehow managed to suspend
2899       return true;
2900     } else {
2901       ShouldNotReachHere();
2902       return false;
2903     }
2904   }
2905 
2906   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2907 
2908   for (int n = 0; !osthread->sr.is_suspended(); n++) {
2909     for (int i = 0; i < RANDOMLY_LARGE_INTEGER2 && !osthread->sr.is_suspended(); i++) {
2910       os::naked_yield();
2911     }
2912 
2913     // timeout, try to cancel the request
2914     if (n >= RANDOMLY_LARGE_INTEGER) {
2915       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2916       if (cancelled == os::SuspendResume::SR_RUNNING) {
2917         return false;
2918       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2919         return true;
2920       } else {
2921         ShouldNotReachHere();
2922         return false;
2923       }
2924     }
2925   }
2926 
2927   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2928   return true;
2929 }
2930 
2931 static void do_resume(OSThread* osthread) {
2932   //assert(osthread->sr.is_suspended(), "thread should be suspended");
2933 
2934   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2935     // failed to switch to WAKEUP_REQUEST
2936     ShouldNotReachHere();
2937     return;
2938   }
2939 
2940   while (!osthread->sr.is_running()) {
2941     if (sr_notify(osthread) == 0) {
2942       for (int n = 0; n < RANDOMLY_LARGE_INTEGER && !osthread->sr.is_running(); n++) {
2943         for (int i = 0; i < 100 && !osthread->sr.is_running(); i++) {
2944           os::naked_yield();
2945         }
2946       }
2947     } else {
2948       ShouldNotReachHere();
2949     }
2950   }
2951 
2952   guarantee(osthread->sr.is_running(), "Must be running!");
2953 }
2954 
2955 ///////////////////////////////////////////////////////////////////////////////////
2956 // signal handling (except suspend/resume)
2957 
2958 // This routine may be used by user applications as a "hook" to catch signals.
2959 // The user-defined signal handler must pass unrecognized signals to this
2960 // routine, and if it returns true (non-zero), then the signal handler must
2961 // return immediately. If the flag "abort_if_unrecognized" is true, then this
2962 // routine will never retun false (zero), but instead will execute a VM panic
2963 // routine kill the process.
2964 //
2965 // If this routine returns false, it is OK to call it again. This allows
2966 // the user-defined signal handler to perform checks either before or after
2967 // the VM performs its own checks. Naturally, the user code would be making
2968 // a serious error if it tried to handle an exception (such as a null check
2969 // or breakpoint) that the VM was generating for its own correct operation.
2970 //
2971 // This routine may recognize any of the following kinds of signals:
2972 //   SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2973 // It should be consulted by handlers for any of those signals.
2974 //
2975 // The caller of this routine must pass in the three arguments supplied
2976 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2977 // field of the structure passed to sigaction(). This routine assumes that
2978 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2979 //
2980 // Note that the VM will print warnings if it detects conflicting signal
2981 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2982 //
2983 extern "C" JNIEXPORT int
2984 JVM_handle_aix_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized);
2985 
2986 // Set thread signal mask (for some reason on AIX sigthreadmask() seems
2987 // to be the thing to call; documentation is not terribly clear about whether
2988 // pthread_sigmask also works, and if it does, whether it does the same.
2989 bool set_thread_signal_mask(int how, const sigset_t* set, sigset_t* oset) {
2990   const int rc = ::pthread_sigmask(how, set, oset);
2991   // return value semantics differ slightly for error case:
2992   // pthread_sigmask returns error number, sigthreadmask -1 and sets global errno
2993   // (so, pthread_sigmask is more theadsafe for error handling)
2994   // But success is always 0.
2995   return rc == 0 ? true : false;
2996 }
2997 
2998 // Function to unblock all signals which are, according
2999 // to POSIX, typical program error signals. If they happen while being blocked,
3000 // they typically will bring down the process immediately.
3001 bool unblock_program_error_signals() {
3002   sigset_t set;
3003   ::sigemptyset(&set);
3004   ::sigaddset(&set, SIGILL);
3005   ::sigaddset(&set, SIGBUS);
3006   ::sigaddset(&set, SIGFPE);
3007   ::sigaddset(&set, SIGSEGV);
3008   return set_thread_signal_mask(SIG_UNBLOCK, &set, NULL);
3009 }
3010 
3011 // Renamed from 'signalHandler' to avoid collision with other shared libs.
3012 void javaSignalHandler(int sig, siginfo_t* info, void* uc) {
3013   assert(info != NULL && uc != NULL, "it must be old kernel");
3014 
3015   // Never leave program error signals blocked;
3016   // on all our platforms they would bring down the process immediately when
3017   // getting raised while being blocked.
3018   unblock_program_error_signals();
3019 
3020   int orig_errno = errno;  // Preserve errno value over signal handler.
3021   JVM_handle_aix_signal(sig, info, uc, true);
3022   errno = orig_errno;
3023 }
3024 
3025 // This boolean allows users to forward their own non-matching signals
3026 // to JVM_handle_aix_signal, harmlessly.
3027 bool os::Aix::signal_handlers_are_installed = false;
3028 
3029 // For signal-chaining
3030 struct sigaction sigact[NSIG];
3031 sigset_t sigs;
3032 bool os::Aix::libjsig_is_loaded = false;
3033 typedef struct sigaction *(*get_signal_t)(int);
3034 get_signal_t os::Aix::get_signal_action = NULL;
3035 
3036 struct sigaction* os::Aix::get_chained_signal_action(int sig) {
3037   struct sigaction *actp = NULL;
3038 
3039   if (libjsig_is_loaded) {
3040     // Retrieve the old signal handler from libjsig
3041     actp = (*get_signal_action)(sig);
3042   }
3043   if (actp == NULL) {
3044     // Retrieve the preinstalled signal handler from jvm
3045     actp = get_preinstalled_handler(sig);
3046   }
3047 
3048   return actp;
3049 }
3050 
3051 static bool call_chained_handler(struct sigaction *actp, int sig,
3052                                  siginfo_t *siginfo, void *context) {
3053   // Call the old signal handler
3054   if (actp->sa_handler == SIG_DFL) {
3055     // It's more reasonable to let jvm treat it as an unexpected exception
3056     // instead of taking the default action.
3057     return false;
3058   } else if (actp->sa_handler != SIG_IGN) {
3059     if ((actp->sa_flags & SA_NODEFER) == 0) {
3060       // automaticlly block the signal
3061       sigaddset(&(actp->sa_mask), sig);
3062     }
3063 
3064     sa_handler_t hand = NULL;
3065     sa_sigaction_t sa = NULL;
3066     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3067     // retrieve the chained handler
3068     if (siginfo_flag_set) {
3069       sa = actp->sa_sigaction;
3070     } else {
3071       hand = actp->sa_handler;
3072     }
3073 
3074     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3075       actp->sa_handler = SIG_DFL;
3076     }
3077 
3078     // try to honor the signal mask
3079     sigset_t oset;
3080     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3081 
3082     // call into the chained handler
3083     if (siginfo_flag_set) {
3084       (*sa)(sig, siginfo, context);
3085     } else {
3086       (*hand)(sig);
3087     }
3088 
3089     // restore the signal mask
3090     pthread_sigmask(SIG_SETMASK, &oset, 0);
3091   }
3092   // Tell jvm's signal handler the signal is taken care of.
3093   return true;
3094 }
3095 
3096 bool os::Aix::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3097   bool chained = false;
3098   // signal-chaining
3099   if (UseSignalChaining) {
3100     struct sigaction *actp = get_chained_signal_action(sig);
3101     if (actp != NULL) {
3102       chained = call_chained_handler(actp, sig, siginfo, context);
3103     }
3104   }
3105   return chained;
3106 }
3107 
3108 struct sigaction* os::Aix::get_preinstalled_handler(int sig) {
3109   if (sigismember(&sigs, sig)) {
3110     return &sigact[sig];
3111   }
3112   return NULL;
3113 }
3114 
3115 void os::Aix::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3116   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3117   sigact[sig] = oldAct;
3118   sigaddset(&sigs, sig);
3119 }
3120 
3121 // for diagnostic
3122 int sigflags[NSIG];
3123 
3124 int os::Aix::get_our_sigflags(int sig) {
3125   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3126   return sigflags[sig];
3127 }
3128 
3129 void os::Aix::set_our_sigflags(int sig, int flags) {
3130   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3131   if (sig > 0 && sig < NSIG) {
3132     sigflags[sig] = flags;
3133   }
3134 }
3135 
3136 void os::Aix::set_signal_handler(int sig, bool set_installed) {
3137   // Check for overwrite.
3138   struct sigaction oldAct;
3139   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3140 
3141   void* oldhand = oldAct.sa_sigaction
3142     ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3143     : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3144   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3145       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3146       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)javaSignalHandler)) {
3147     if (AllowUserSignalHandlers || !set_installed) {
3148       // Do not overwrite; user takes responsibility to forward to us.
3149       return;
3150     } else if (UseSignalChaining) {
3151       // save the old handler in jvm
3152       save_preinstalled_handler(sig, oldAct);
3153       // libjsig also interposes the sigaction() call below and saves the
3154       // old sigaction on it own.
3155     } else {
3156       fatal("Encountered unexpected pre-existing sigaction handler "
3157             "%#lx for signal %d.", (long)oldhand, sig);
3158     }
3159   }
3160 
3161   struct sigaction sigAct;
3162   sigfillset(&(sigAct.sa_mask));
3163   if (!set_installed) {
3164     sigAct.sa_handler = SIG_DFL;
3165     sigAct.sa_flags = SA_RESTART;
3166   } else {
3167     sigAct.sa_sigaction = javaSignalHandler;
3168     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3169   }
3170   // Save flags, which are set by ours
3171   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3172   sigflags[sig] = sigAct.sa_flags;
3173 
3174   int ret = sigaction(sig, &sigAct, &oldAct);
3175   assert(ret == 0, "check");
3176 
3177   void* oldhand2 = oldAct.sa_sigaction
3178                  ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3179                  : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3180   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3181 }
3182 
3183 // install signal handlers for signals that HotSpot needs to
3184 // handle in order to support Java-level exception handling.
3185 void os::Aix::install_signal_handlers() {
3186   if (!signal_handlers_are_installed) {
3187     signal_handlers_are_installed = true;
3188 
3189     // signal-chaining
3190     typedef void (*signal_setting_t)();
3191     signal_setting_t begin_signal_setting = NULL;
3192     signal_setting_t end_signal_setting = NULL;
3193     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3194                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3195     if (begin_signal_setting != NULL) {
3196       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3197                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3198       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3199                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3200       libjsig_is_loaded = true;
3201       assert(UseSignalChaining, "should enable signal-chaining");
3202     }
3203     if (libjsig_is_loaded) {
3204       // Tell libjsig jvm is setting signal handlers.
3205       (*begin_signal_setting)();
3206     }
3207 
3208     ::sigemptyset(&sigs);
3209     set_signal_handler(SIGSEGV, true);
3210     set_signal_handler(SIGPIPE, true);
3211     set_signal_handler(SIGBUS, true);
3212     set_signal_handler(SIGILL, true);
3213     set_signal_handler(SIGFPE, true);
3214     set_signal_handler(SIGTRAP, true);
3215     set_signal_handler(SIGXFSZ, true);
3216 
3217     if (libjsig_is_loaded) {
3218       // Tell libjsig jvm finishes setting signal handlers.
3219       (*end_signal_setting)();
3220     }
3221 
3222     // We don't activate signal checker if libjsig is in place, we trust ourselves
3223     // and if UserSignalHandler is installed all bets are off.
3224     // Log that signal checking is off only if -verbose:jni is specified.
3225     if (CheckJNICalls) {
3226       if (libjsig_is_loaded) {
3227         tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3228         check_signals = false;
3229       }
3230       if (AllowUserSignalHandlers) {
3231         tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3232         check_signals = false;
3233       }
3234       // Need to initialize check_signal_done.
3235       ::sigemptyset(&check_signal_done);
3236     }
3237   }
3238 }
3239 
3240 static const char* get_signal_handler_name(address handler,
3241                                            char* buf, int buflen) {
3242   int offset;
3243   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3244   if (found) {
3245     // skip directory names
3246     const char *p1, *p2;
3247     p1 = buf;
3248     size_t len = strlen(os::file_separator());
3249     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3250     // The way os::dll_address_to_library_name is implemented on Aix
3251     // right now, it always returns -1 for the offset which is not
3252     // terribly informative.
3253     // Will fix that. For now, omit the offset.
3254     jio_snprintf(buf, buflen, "%s", p1);
3255   } else {
3256     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3257   }
3258   return buf;
3259 }
3260 
3261 static void print_signal_handler(outputStream* st, int sig,
3262                                  char* buf, size_t buflen) {
3263   struct sigaction sa;
3264   sigaction(sig, NULL, &sa);
3265 
3266   st->print("%s: ", os::exception_name(sig, buf, buflen));
3267 
3268   address handler = (sa.sa_flags & SA_SIGINFO)
3269     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3270     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3271 
3272   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3273     st->print("SIG_DFL");
3274   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3275     st->print("SIG_IGN");
3276   } else {
3277     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3278   }
3279 
3280   // Print readable mask.
3281   st->print(", sa_mask[0]=");
3282   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3283 
3284   address rh = VMError::get_resetted_sighandler(sig);
3285   // May be, handler was resetted by VMError?
3286   if (rh != NULL) {
3287     handler = rh;
3288     sa.sa_flags = VMError::get_resetted_sigflags(sig);
3289   }
3290 
3291   // Print textual representation of sa_flags.
3292   st->print(", sa_flags=");
3293   os::Posix::print_sa_flags(st, sa.sa_flags);
3294 
3295   // Check: is it our handler?
3296   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler) ||
3297       handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3298     // It is our signal handler.
3299     // Check for flags, reset system-used one!
3300     if ((int)sa.sa_flags != os::Aix::get_our_sigflags(sig)) {
3301       st->print(", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3302                 os::Aix::get_our_sigflags(sig));
3303     }
3304   }
3305   st->cr();
3306 }
3307 
3308 #define DO_SIGNAL_CHECK(sig) \
3309   if (!sigismember(&check_signal_done, sig)) \
3310     os::Aix::check_signal_handler(sig)
3311 
3312 // This method is a periodic task to check for misbehaving JNI applications
3313 // under CheckJNI, we can add any periodic checks here
3314 
3315 void os::run_periodic_checks() {
3316 
3317   if (check_signals == false) return;
3318 
3319   // SEGV and BUS if overridden could potentially prevent
3320   // generation of hs*.log in the event of a crash, debugging
3321   // such a case can be very challenging, so we absolutely
3322   // check the following for a good measure:
3323   DO_SIGNAL_CHECK(SIGSEGV);
3324   DO_SIGNAL_CHECK(SIGILL);
3325   DO_SIGNAL_CHECK(SIGFPE);
3326   DO_SIGNAL_CHECK(SIGBUS);
3327   DO_SIGNAL_CHECK(SIGPIPE);
3328   DO_SIGNAL_CHECK(SIGXFSZ);
3329   if (UseSIGTRAP) {
3330     DO_SIGNAL_CHECK(SIGTRAP);
3331   }
3332 
3333   // ReduceSignalUsage allows the user to override these handlers
3334   // see comments at the very top and jvm_md.h
3335   if (!ReduceSignalUsage) {
3336     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3337     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3338     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3339     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3340   }
3341 
3342   DO_SIGNAL_CHECK(SR_signum);
3343 }
3344 
3345 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3346 
3347 static os_sigaction_t os_sigaction = NULL;
3348 
3349 void os::Aix::check_signal_handler(int sig) {
3350   char buf[O_BUFLEN];
3351   address jvmHandler = NULL;
3352 
3353   struct sigaction act;
3354   if (os_sigaction == NULL) {
3355     // only trust the default sigaction, in case it has been interposed
3356     os_sigaction = CAST_TO_FN_PTR(os_sigaction_t, dlsym(RTLD_DEFAULT, "sigaction"));
3357     if (os_sigaction == NULL) return;
3358   }
3359 
3360   os_sigaction(sig, (struct sigaction*)NULL, &act);
3361 
3362   address thisHandler = (act.sa_flags & SA_SIGINFO)
3363     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3364     : CAST_FROM_FN_PTR(address, act.sa_handler);
3365 
3366   switch(sig) {
3367   case SIGSEGV:
3368   case SIGBUS:
3369   case SIGFPE:
3370   case SIGPIPE:
3371   case SIGILL:
3372   case SIGXFSZ:
3373     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler);
3374     break;
3375 
3376   case SHUTDOWN1_SIGNAL:
3377   case SHUTDOWN2_SIGNAL:
3378   case SHUTDOWN3_SIGNAL:
3379   case BREAK_SIGNAL:
3380     jvmHandler = (address)user_handler();
3381     break;
3382 
3383   default:
3384     if (sig == SR_signum) {
3385       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3386     } else {
3387       return;
3388     }
3389     break;
3390   }
3391 
3392   if (thisHandler != jvmHandler) {
3393     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3394     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3395     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3396     // No need to check this sig any longer
3397     sigaddset(&check_signal_done, sig);
3398     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3399     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3400       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3401                     exception_name(sig, buf, O_BUFLEN));
3402     }
3403   } else if (os::Aix::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Aix::get_our_sigflags(sig)) {
3404     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3405     tty->print("expected:");
3406     os::Posix::print_sa_flags(tty, os::Aix::get_our_sigflags(sig));
3407     tty->cr();
3408     tty->print("  found:");
3409     os::Posix::print_sa_flags(tty, act.sa_flags);
3410     tty->cr();
3411     // No need to check this sig any longer
3412     sigaddset(&check_signal_done, sig);
3413   }
3414 
3415   // Dump all the signal
3416   if (sigismember(&check_signal_done, sig)) {
3417     print_signal_handlers(tty, buf, O_BUFLEN);
3418   }
3419 }
3420 
3421 // To install functions for atexit system call
3422 extern "C" {
3423   static void perfMemory_exit_helper() {
3424     perfMemory_exit();
3425   }
3426 }
3427 
3428 // This is called _before_ the most of global arguments have been parsed.
3429 void os::init(void) {
3430   // This is basic, we want to know if that ever changes.
3431   // (Shared memory boundary is supposed to be a 256M aligned.)
3432   assert(SHMLBA == ((uint64_t)0x10000000ULL)/*256M*/, "unexpected");
3433 
3434   // Record process break at startup.
3435   g_brk_at_startup = (address) ::sbrk(0);
3436   assert(g_brk_at_startup != (address) -1, "sbrk failed");
3437 
3438   // First off, we need to know whether we run on AIX or PASE, and
3439   // the OS level we run on.
3440   os::Aix::initialize_os_info();
3441 
3442   // Scan environment (SPEC1170 behaviour, etc).
3443   os::Aix::scan_environment();
3444 
3445   // Probe multipage support.
3446   query_multipage_support();
3447 
3448   // Act like we only have one page size by eliminating corner cases which
3449   // we did not support very well anyway.
3450   // We have two input conditions:
3451   // 1) Data segment page size. This is controlled by linker setting (datapsize) on the
3452   //    launcher, and/or by LDR_CNTRL environment variable. The latter overrules the linker
3453   //    setting.
3454   //    Data segment page size is important for us because it defines the thread stack page
3455   //    size, which is needed for guard page handling, stack banging etc.
3456   // 2) The ability to allocate 64k pages dynamically. If this is a given, java heap can
3457   //    and should be allocated with 64k pages.
3458   //
3459   // So, we do the following:
3460   // LDR_CNTRL    can_use_64K_pages_dynamically       what we do                      remarks
3461   // 4K           no                                  4K                              old systems (aix 5.2, as/400 v5r4) or new systems with AME activated
3462   // 4k           yes                                 64k (treat 4k stacks as 64k)    different loader than java and standard settings
3463   // 64k          no              --- AIX 5.2 ? ---
3464   // 64k          yes                                 64k                             new systems and standard java loader (we set datapsize=64k when linking)
3465 
3466   // We explicitly leave no option to change page size, because only upgrading would work,
3467   // not downgrading (if stack page size is 64k you cannot pretend its 4k).
3468 
3469   if (g_multipage_support.datapsize == 4*K) {
3470     // datapsize = 4K. Data segment, thread stacks are 4K paged.
3471     if (g_multipage_support.can_use_64K_pages) {
3472       // .. but we are able to use 64K pages dynamically.
3473       // This would be typical for java launchers which are not linked
3474       // with datapsize=64K (like, any other launcher but our own).
3475       //
3476       // In this case it would be smart to allocate the java heap with 64K
3477       // to get the performance benefit, and to fake 64k pages for the
3478       // data segment (when dealing with thread stacks).
3479       //
3480       // However, leave a possibility to downgrade to 4K, using
3481       // -XX:-Use64KPages.
3482       if (Use64KPages) {
3483         trcVerbose("64K page mode (faked for data segment)");
3484         Aix::_page_size = 64*K;
3485       } else {
3486         trcVerbose("4K page mode (Use64KPages=off)");
3487         Aix::_page_size = 4*K;
3488       }
3489     } else {
3490       // .. and not able to allocate 64k pages dynamically. Here, just
3491       // fall back to 4K paged mode and use mmap for everything.
3492       trcVerbose("4K page mode");
3493       Aix::_page_size = 4*K;
3494       FLAG_SET_ERGO(bool, Use64KPages, false);
3495     }
3496   } else {
3497     // datapsize = 64k. Data segment, thread stacks are 64k paged.
3498     // This normally means that we can allocate 64k pages dynamically.
3499     // (There is one special case where this may be false: EXTSHM=on.
3500     // but we decided to not support that mode).
3501     assert0(g_multipage_support.can_use_64K_pages);
3502     Aix::_page_size = 64*K;
3503     trcVerbose("64K page mode");
3504     FLAG_SET_ERGO(bool, Use64KPages, true);
3505   }
3506 
3507   // For now UseLargePages is just ignored.
3508   FLAG_SET_ERGO(bool, UseLargePages, false);
3509   _page_sizes[0] = 0;
3510 
3511   // debug trace
3512   trcVerbose("os::vm_page_size %s", describe_pagesize(os::vm_page_size()));
3513 
3514   // Next, we need to initialize libo4 and libperfstat libraries.
3515   if (os::Aix::on_pase()) {
3516     os::Aix::initialize_libo4();
3517   } else {
3518     os::Aix::initialize_libperfstat();
3519   }
3520 
3521   // Reset the perfstat information provided by ODM.
3522   if (os::Aix::on_aix()) {
3523     libperfstat::perfstat_reset();
3524   }
3525 
3526   // Now initialze basic system properties. Note that for some of the values we
3527   // need libperfstat etc.
3528   os::Aix::initialize_system_info();
3529 
3530   clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3531 
3532   init_random(1234567);
3533 
3534   // _main_thread points to the thread that created/loaded the JVM.
3535   Aix::_main_thread = pthread_self();
3536 
3537   initial_time_count = os::elapsed_counter();
3538 
3539   os::Posix::init();
3540 }
3541 
3542 // This is called _after_ the global arguments have been parsed.
3543 jint os::init_2(void) {
3544 
3545   os::Posix::init_2();
3546 
3547   if (os::Aix::on_pase()) {
3548     trcVerbose("Running on PASE.");
3549   } else {
3550     trcVerbose("Running on AIX (not PASE).");
3551   }
3552 
3553   trcVerbose("processor count: %d", os::_processor_count);
3554   trcVerbose("physical memory: %lu", Aix::_physical_memory);
3555 
3556   // Initially build up the loaded dll map.
3557   LoadedLibraries::reload();
3558   if (Verbose) {
3559     trcVerbose("Loaded Libraries: ");
3560     LoadedLibraries::print(tty);
3561   }
3562 
3563   // initialize suspend/resume support - must do this before signal_sets_init()
3564   if (SR_initialize() != 0) {
3565     perror("SR_initialize failed");
3566     return JNI_ERR;
3567   }
3568 
3569   Aix::signal_sets_init();
3570   Aix::install_signal_handlers();
3571 
3572   // Check and sets minimum stack sizes against command line options
3573   if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
3574     return JNI_ERR;
3575   }
3576 
3577   if (UseNUMA) {
3578     UseNUMA = false;
3579     warning("NUMA optimizations are not available on this OS.");
3580   }
3581 
3582   if (MaxFDLimit) {
3583     // Set the number of file descriptors to max. print out error
3584     // if getrlimit/setrlimit fails but continue regardless.
3585     struct rlimit nbr_files;
3586     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3587     if (status != 0) {
3588       log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
3589     } else {
3590       nbr_files.rlim_cur = nbr_files.rlim_max;
3591       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3592       if (status != 0) {
3593         log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
3594       }
3595     }
3596   }
3597 
3598   if (PerfAllowAtExitRegistration) {
3599     // Only register atexit functions if PerfAllowAtExitRegistration is set.
3600     // At exit functions can be delayed until process exit time, which
3601     // can be problematic for embedded VM situations. Embedded VMs should
3602     // call DestroyJavaVM() to assure that VM resources are released.
3603 
3604     // Note: perfMemory_exit_helper atexit function may be removed in
3605     // the future if the appropriate cleanup code can be added to the
3606     // VM_Exit VMOperation's doit method.
3607     if (atexit(perfMemory_exit_helper) != 0) {
3608       warning("os::init_2 atexit(perfMemory_exit_helper) failed");
3609     }
3610   }
3611 
3612   return JNI_OK;
3613 }
3614 
3615 // Mark the polling page as unreadable
3616 void os::make_polling_page_unreadable(void) {
3617   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
3618     fatal("Could not disable polling page");
3619   }
3620 };
3621 
3622 // Mark the polling page as readable
3623 void os::make_polling_page_readable(void) {
3624   // Changed according to os_linux.cpp.
3625   if (!checked_mprotect((char *)_polling_page, Aix::page_size(), PROT_READ)) {
3626     fatal("Could not enable polling page at " PTR_FORMAT, _polling_page);
3627   }
3628 };
3629 
3630 int os::active_processor_count() {
3631   // User has overridden the number of active processors
3632   if (ActiveProcessorCount > 0) {
3633     log_trace(os)("active_processor_count: "
3634                   "active processor count set by user : %d",
3635                   ActiveProcessorCount);
3636     return ActiveProcessorCount;
3637   }
3638 
3639   int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3640   assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3641   return online_cpus;
3642 }
3643 
3644 void os::set_native_thread_name(const char *name) {
3645   // Not yet implemented.
3646   return;
3647 }
3648 
3649 bool os::distribute_processes(uint length, uint* distribution) {
3650   // Not yet implemented.
3651   return false;
3652 }
3653 
3654 bool os::bind_to_processor(uint processor_id) {
3655   // Not yet implemented.
3656   return false;
3657 }
3658 
3659 void os::SuspendedThreadTask::internal_do_task() {
3660   if (do_suspend(_thread->osthread())) {
3661     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3662     do_task(context);
3663     do_resume(_thread->osthread());
3664   }
3665 }
3666 
3667 ////////////////////////////////////////////////////////////////////////////////
3668 // debug support
3669 
3670 bool os::find(address addr, outputStream* st) {
3671 
3672   st->print(PTR_FORMAT ": ", addr);
3673 
3674   loaded_module_t lm;
3675   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL ||
3676       LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
3677     st->print_cr("%s", lm.path);
3678     return true;
3679   }
3680 
3681   return false;
3682 }
3683 
3684 ////////////////////////////////////////////////////////////////////////////////
3685 // misc
3686 
3687 // This does not do anything on Aix. This is basically a hook for being
3688 // able to use structured exception handling (thread-local exception filters)
3689 // on, e.g., Win32.
3690 void
3691 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
3692                          JavaCallArguments* args, Thread* thread) {
3693   f(value, method, args, thread);
3694 }
3695 
3696 void os::print_statistics() {
3697 }
3698 
3699 bool os::message_box(const char* title, const char* message) {
3700   int i;
3701   fdStream err(defaultStream::error_fd());
3702   for (i = 0; i < 78; i++) err.print_raw("=");
3703   err.cr();
3704   err.print_raw_cr(title);
3705   for (i = 0; i < 78; i++) err.print_raw("-");
3706   err.cr();
3707   err.print_raw_cr(message);
3708   for (i = 0; i < 78; i++) err.print_raw("=");
3709   err.cr();
3710 
3711   char buf[16];
3712   // Prevent process from exiting upon "read error" without consuming all CPU
3713   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3714 
3715   return buf[0] == 'y' || buf[0] == 'Y';
3716 }
3717 
3718 int os::stat(const char *path, struct stat *sbuf) {
3719   char pathbuf[MAX_PATH];
3720   if (strlen(path) > MAX_PATH - 1) {
3721     errno = ENAMETOOLONG;
3722     return -1;
3723   }
3724   os::native_path(strcpy(pathbuf, path));
3725   return ::stat(pathbuf, sbuf);
3726 }
3727 
3728 // Is a (classpath) directory empty?
3729 bool os::dir_is_empty(const char* path) {
3730   DIR *dir = NULL;
3731   struct dirent *ptr;
3732 
3733   dir = opendir(path);
3734   if (dir == NULL) return true;
3735 
3736   /* Scan the directory */
3737   bool result = true;
3738   char buf[sizeof(struct dirent) + MAX_PATH];
3739   while (result && (ptr = ::readdir(dir)) != NULL) {
3740     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3741       result = false;
3742     }
3743   }
3744   closedir(dir);
3745   return result;
3746 }
3747 
3748 // This code originates from JDK's sysOpen and open64_w
3749 // from src/solaris/hpi/src/system_md.c
3750 
3751 int os::open(const char *path, int oflag, int mode) {
3752 
3753   if (strlen(path) > MAX_PATH - 1) {
3754     errno = ENAMETOOLONG;
3755     return -1;
3756   }
3757   int fd;
3758 
3759   fd = ::open64(path, oflag, mode);
3760   if (fd == -1) return -1;
3761 
3762   // If the open succeeded, the file might still be a directory.
3763   {
3764     struct stat64 buf64;
3765     int ret = ::fstat64(fd, &buf64);
3766     int st_mode = buf64.st_mode;
3767 
3768     if (ret != -1) {
3769       if ((st_mode & S_IFMT) == S_IFDIR) {
3770         errno = EISDIR;
3771         ::close(fd);
3772         return -1;
3773       }
3774     } else {
3775       ::close(fd);
3776       return -1;
3777     }
3778   }
3779 
3780   // All file descriptors that are opened in the JVM and not
3781   // specifically destined for a subprocess should have the
3782   // close-on-exec flag set. If we don't set it, then careless 3rd
3783   // party native code might fork and exec without closing all
3784   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3785   // UNIXProcess.c), and this in turn might:
3786   //
3787   // - cause end-of-file to fail to be detected on some file
3788   //   descriptors, resulting in mysterious hangs, or
3789   //
3790   // - might cause an fopen in the subprocess to fail on a system
3791   //   suffering from bug 1085341.
3792   //
3793   // (Yes, the default setting of the close-on-exec flag is a Unix
3794   // design flaw.)
3795   //
3796   // See:
3797   // 1085341: 32-bit stdio routines should support file descriptors >255
3798   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3799   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3800 #ifdef FD_CLOEXEC
3801   {
3802     int flags = ::fcntl(fd, F_GETFD);
3803     if (flags != -1)
3804       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3805   }
3806 #endif
3807 
3808   return fd;
3809 }
3810 
3811 // create binary file, rewriting existing file if required
3812 int os::create_binary_file(const char* path, bool rewrite_existing) {
3813   int oflags = O_WRONLY | O_CREAT;
3814   if (!rewrite_existing) {
3815     oflags |= O_EXCL;
3816   }
3817   return ::open64(path, oflags, S_IREAD | S_IWRITE);
3818 }
3819 
3820 // return current position of file pointer
3821 jlong os::current_file_offset(int fd) {
3822   return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
3823 }
3824 
3825 // move file pointer to the specified offset
3826 jlong os::seek_to_file_offset(int fd, jlong offset) {
3827   return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
3828 }
3829 
3830 // This code originates from JDK's sysAvailable
3831 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3832 
3833 int os::available(int fd, jlong *bytes) {
3834   jlong cur, end;
3835   int mode;
3836   struct stat64 buf64;
3837 
3838   if (::fstat64(fd, &buf64) >= 0) {
3839     mode = buf64.st_mode;
3840     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3841       int n;
3842       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3843         *bytes = n;
3844         return 1;
3845       }
3846     }
3847   }
3848   if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
3849     return 0;
3850   } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
3851     return 0;
3852   } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
3853     return 0;
3854   }
3855   *bytes = end - cur;
3856   return 1;
3857 }
3858 
3859 // Map a block of memory.
3860 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3861                         char *addr, size_t bytes, bool read_only,
3862                         bool allow_exec) {
3863   int prot;
3864   int flags = MAP_PRIVATE;
3865 
3866   if (read_only) {
3867     prot = PROT_READ;
3868     flags = MAP_SHARED;
3869   } else {
3870     prot = PROT_READ | PROT_WRITE;
3871     flags = MAP_PRIVATE;
3872   }
3873 
3874   if (allow_exec) {
3875     prot |= PROT_EXEC;
3876   }
3877 
3878   if (addr != NULL) {
3879     flags |= MAP_FIXED;
3880   }
3881 
3882   // Allow anonymous mappings if 'fd' is -1.
3883   if (fd == -1) {
3884     flags |= MAP_ANONYMOUS;
3885   }
3886 
3887   char* mapped_address = (char*)::mmap(addr, (size_t)bytes, prot, flags,
3888                                      fd, file_offset);
3889   if (mapped_address == MAP_FAILED) {
3890     return NULL;
3891   }
3892   return mapped_address;
3893 }
3894 
3895 // Remap a block of memory.
3896 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3897                           char *addr, size_t bytes, bool read_only,
3898                           bool allow_exec) {
3899   // same as map_memory() on this OS
3900   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3901                         allow_exec);
3902 }
3903 
3904 // Unmap a block of memory.
3905 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3906   return munmap(addr, bytes) == 0;
3907 }
3908 
3909 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3910 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3911 // of a thread.
3912 //
3913 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3914 // the fast estimate available on the platform.
3915 
3916 jlong os::current_thread_cpu_time() {
3917   // return user + sys since the cost is the same
3918   const jlong n = os::thread_cpu_time(Thread::current(), true /* user + sys */);
3919   assert(n >= 0, "negative CPU time");
3920   return n;
3921 }
3922 
3923 jlong os::thread_cpu_time(Thread* thread) {
3924   // consistent with what current_thread_cpu_time() returns
3925   const jlong n = os::thread_cpu_time(thread, true /* user + sys */);
3926   assert(n >= 0, "negative CPU time");
3927   return n;
3928 }
3929 
3930 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
3931   const jlong n = os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
3932   assert(n >= 0, "negative CPU time");
3933   return n;
3934 }
3935 
3936 static bool thread_cpu_time_unchecked(Thread* thread, jlong* p_sys_time, jlong* p_user_time) {
3937   bool error = false;
3938 
3939   jlong sys_time = 0;
3940   jlong user_time = 0;
3941 
3942   // Reimplemented using getthrds64().
3943   //
3944   // Works like this:
3945   // For the thread in question, get the kernel thread id. Then get the
3946   // kernel thread statistics using that id.
3947   //
3948   // This only works of course when no pthread scheduling is used,
3949   // i.e. there is a 1:1 relationship to kernel threads.
3950   // On AIX, see AIXTHREAD_SCOPE variable.
3951 
3952   pthread_t pthtid = thread->osthread()->pthread_id();
3953 
3954   // retrieve kernel thread id for the pthread:
3955   tid64_t tid = 0;
3956   struct __pthrdsinfo pinfo;
3957   // I just love those otherworldly IBM APIs which force me to hand down
3958   // dummy buffers for stuff I dont care for...
3959   char dummy[1];
3960   int dummy_size = sizeof(dummy);
3961   if (pthread_getthrds_np(&pthtid, PTHRDSINFO_QUERY_TID, &pinfo, sizeof(pinfo),
3962                           dummy, &dummy_size) == 0) {
3963     tid = pinfo.__pi_tid;
3964   } else {
3965     tty->print_cr("pthread_getthrds_np failed.");
3966     error = true;
3967   }
3968 
3969   // retrieve kernel timing info for that kernel thread
3970   if (!error) {
3971     struct thrdentry64 thrdentry;
3972     if (getthrds64(getpid(), &thrdentry, sizeof(thrdentry), &tid, 1) == 1) {
3973       sys_time = thrdentry.ti_ru.ru_stime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_stime.tv_usec * 1000LL;
3974       user_time = thrdentry.ti_ru.ru_utime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_utime.tv_usec * 1000LL;
3975     } else {
3976       tty->print_cr("pthread_getthrds_np failed.");
3977       error = true;
3978     }
3979   }
3980 
3981   if (p_sys_time) {
3982     *p_sys_time = sys_time;
3983   }
3984 
3985   if (p_user_time) {
3986     *p_user_time = user_time;
3987   }
3988 
3989   if (error) {
3990     return false;
3991   }
3992 
3993   return true;
3994 }
3995 
3996 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
3997   jlong sys_time;
3998   jlong user_time;
3999 
4000   if (!thread_cpu_time_unchecked(thread, &sys_time, &user_time)) {
4001     return -1;
4002   }
4003 
4004   return user_sys_cpu_time ? sys_time + user_time : user_time;
4005 }
4006 
4007 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4008   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4009   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4010   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4011   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4012 }
4013 
4014 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4015   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4016   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4017   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4018   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4019 }
4020 
4021 bool os::is_thread_cpu_time_supported() {
4022   return true;
4023 }
4024 
4025 // System loadavg support. Returns -1 if load average cannot be obtained.
4026 // For now just return the system wide load average (no processor sets).
4027 int os::loadavg(double values[], int nelem) {
4028 
4029   guarantee(nelem >= 0 && nelem <= 3, "argument error");
4030   guarantee(values, "argument error");
4031 
4032   if (os::Aix::on_pase()) {
4033 
4034     // AS/400 PASE: use libo4 porting library
4035     double v[3] = { 0.0, 0.0, 0.0 };
4036 
4037     if (libo4::get_load_avg(v, v + 1, v + 2)) {
4038       for (int i = 0; i < nelem; i ++) {
4039         values[i] = v[i];
4040       }
4041       return nelem;
4042     } else {
4043       return -1;
4044     }
4045 
4046   } else {
4047 
4048     // AIX: use libperfstat
4049     libperfstat::cpuinfo_t ci;
4050     if (libperfstat::get_cpuinfo(&ci)) {
4051       for (int i = 0; i < nelem; i++) {
4052         values[i] = ci.loadavg[i];
4053       }
4054     } else {
4055       return -1;
4056     }
4057     return nelem;
4058   }
4059 }
4060 
4061 void os::pause() {
4062   char filename[MAX_PATH];
4063   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4064     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4065   } else {
4066     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4067   }
4068 
4069   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4070   if (fd != -1) {
4071     struct stat buf;
4072     ::close(fd);
4073     while (::stat(filename, &buf) == 0) {
4074       (void)::poll(NULL, 0, 100);
4075     }
4076   } else {
4077     trcVerbose("Could not open pause file '%s', continuing immediately.", filename);
4078   }
4079 }
4080 
4081 bool os::is_primordial_thread(void) {
4082   if (pthread_self() == (pthread_t)1) {
4083     return true;
4084   } else {
4085     return false;
4086   }
4087 }
4088 
4089 // OS recognitions (PASE/AIX, OS level) call this before calling any
4090 // one of Aix::on_pase(), Aix::os_version() static
4091 void os::Aix::initialize_os_info() {
4092 
4093   assert(_on_pase == -1 && _os_version == 0, "already called.");
4094 
4095   struct utsname uts;
4096   memset(&uts, 0, sizeof(uts));
4097   strcpy(uts.sysname, "?");
4098   if (::uname(&uts) == -1) {
4099     trcVerbose("uname failed (%d)", errno);
4100     guarantee(0, "Could not determine whether we run on AIX or PASE");
4101   } else {
4102     trcVerbose("uname says: sysname \"%s\" version \"%s\" release \"%s\" "
4103                "node \"%s\" machine \"%s\"\n",
4104                uts.sysname, uts.version, uts.release, uts.nodename, uts.machine);
4105     const int major = atoi(uts.version);
4106     assert(major > 0, "invalid OS version");
4107     const int minor = atoi(uts.release);
4108     assert(minor > 0, "invalid OS release");
4109     _os_version = (major << 24) | (minor << 16);
4110     char ver_str[20] = {0};
4111     char *name_str = "unknown OS";
4112     if (strcmp(uts.sysname, "OS400") == 0) {
4113       // We run on AS/400 PASE. We do not support versions older than V5R4M0.
4114       _on_pase = 1;
4115       if (os_version_short() < 0x0504) {
4116         trcVerbose("OS/400 releases older than V5R4M0 not supported.");
4117         assert(false, "OS/400 release too old.");
4118       }
4119       name_str = "OS/400 (pase)";
4120       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u", major, minor);
4121     } else if (strcmp(uts.sysname, "AIX") == 0) {
4122       // We run on AIX. We do not support versions older than AIX 5.3.
4123       _on_pase = 0;
4124       // Determine detailed AIX version: Version, Release, Modification, Fix Level.
4125       odmWrapper::determine_os_kernel_version(&_os_version);
4126       if (os_version_short() < 0x0503) {
4127         trcVerbose("AIX release older than AIX 5.3 not supported.");
4128         assert(false, "AIX release too old.");
4129       }
4130       name_str = "AIX";
4131       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u.%u.%u",
4132                    major, minor, (_os_version >> 8) & 0xFF, _os_version & 0xFF);
4133     } else {
4134       assert(false, name_str);
4135     }
4136     trcVerbose("We run on %s %s", name_str, ver_str);
4137   }
4138 
4139   guarantee(_on_pase != -1 && _os_version, "Could not determine AIX/OS400 release");
4140 } // end: os::Aix::initialize_os_info()
4141 
4142 // Scan environment for important settings which might effect the VM.
4143 // Trace out settings. Warn about invalid settings and/or correct them.
4144 //
4145 // Must run after os::Aix::initialue_os_info().
4146 void os::Aix::scan_environment() {
4147 
4148   char* p;
4149   int rc;
4150 
4151   // Warn explicity if EXTSHM=ON is used. That switch changes how
4152   // System V shared memory behaves. One effect is that page size of
4153   // shared memory cannot be change dynamically, effectivly preventing
4154   // large pages from working.
4155   // This switch was needed on AIX 32bit, but on AIX 64bit the general
4156   // recommendation is (in OSS notes) to switch it off.
4157   p = ::getenv("EXTSHM");
4158   trcVerbose("EXTSHM=%s.", p ? p : "<unset>");
4159   if (p && strcasecmp(p, "ON") == 0) {
4160     _extshm = 1;
4161     trcVerbose("*** Unsupported mode! Please remove EXTSHM from your environment! ***");
4162     if (!AllowExtshm) {
4163       // We allow under certain conditions the user to continue. However, we want this
4164       // to be a fatal error by default. On certain AIX systems, leaving EXTSHM=ON means
4165       // that the VM is not able to allocate 64k pages for the heap.
4166       // We do not want to run with reduced performance.
4167       vm_exit_during_initialization("EXTSHM is ON. Please remove EXTSHM from your environment.");
4168     }
4169   } else {
4170     _extshm = 0;
4171   }
4172 
4173   // SPEC1170 behaviour: will change the behaviour of a number of POSIX APIs.
4174   // Not tested, not supported.
4175   //
4176   // Note that it might be worth the trouble to test and to require it, if only to
4177   // get useful return codes for mprotect.
4178   //
4179   // Note: Setting XPG_SUS_ENV in the process is too late. Must be set earlier (before
4180   // exec() ? before loading the libjvm ? ....)
4181   p = ::getenv("XPG_SUS_ENV");
4182   trcVerbose("XPG_SUS_ENV=%s.", p ? p : "<unset>");
4183   if (p && strcmp(p, "ON") == 0) {
4184     _xpg_sus_mode = 1;
4185     trcVerbose("Unsupported setting: XPG_SUS_ENV=ON");
4186     // This is not supported. Worst of all, it changes behaviour of mmap MAP_FIXED to
4187     // clobber address ranges. If we ever want to support that, we have to do some
4188     // testing first.
4189     guarantee(false, "XPG_SUS_ENV=ON not supported");
4190   } else {
4191     _xpg_sus_mode = 0;
4192   }
4193 
4194   if (os::Aix::on_pase()) {
4195     p = ::getenv("QIBM_MULTI_THREADED");
4196     trcVerbose("QIBM_MULTI_THREADED=%s.", p ? p : "<unset>");
4197   }
4198 
4199   p = ::getenv("LDR_CNTRL");
4200   trcVerbose("LDR_CNTRL=%s.", p ? p : "<unset>");
4201   if (os::Aix::on_pase() && os::Aix::os_version_short() == 0x0701) {
4202     if (p && ::strstr(p, "TEXTPSIZE")) {
4203       trcVerbose("*** WARNING - LDR_CNTRL contains TEXTPSIZE. "
4204         "you may experience hangs or crashes on OS/400 V7R1.");
4205     }
4206   }
4207 
4208   p = ::getenv("AIXTHREAD_GUARDPAGES");
4209   trcVerbose("AIXTHREAD_GUARDPAGES=%s.", p ? p : "<unset>");
4210 
4211 } // end: os::Aix::scan_environment()
4212 
4213 // PASE: initialize the libo4 library (PASE porting library).
4214 void os::Aix::initialize_libo4() {
4215   guarantee(os::Aix::on_pase(), "OS/400 only.");
4216   if (!libo4::init()) {
4217     trcVerbose("libo4 initialization failed.");
4218     assert(false, "libo4 initialization failed");
4219   } else {
4220     trcVerbose("libo4 initialized.");
4221   }
4222 }
4223 
4224 // AIX: initialize the libperfstat library.
4225 void os::Aix::initialize_libperfstat() {
4226   assert(os::Aix::on_aix(), "AIX only");
4227   if (!libperfstat::init()) {
4228     trcVerbose("libperfstat initialization failed.");
4229     assert(false, "libperfstat initialization failed");
4230   } else {
4231     trcVerbose("libperfstat initialized.");
4232   }
4233 }
4234 
4235 /////////////////////////////////////////////////////////////////////////////
4236 // thread stack
4237 
4238 // Get the current stack base from the OS (actually, the pthread library).
4239 // Note: usually not page aligned.
4240 address os::current_stack_base() {
4241   AixMisc::stackbounds_t bounds;
4242   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4243   guarantee(rc, "Unable to retrieve stack bounds.");
4244   return bounds.base;
4245 }
4246 
4247 // Get the current stack size from the OS (actually, the pthread library).
4248 // Returned size is such that (base - size) is always aligned to page size.
4249 size_t os::current_stack_size() {
4250   AixMisc::stackbounds_t bounds;
4251   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4252   guarantee(rc, "Unable to retrieve stack bounds.");
4253   // Align the returned stack size such that the stack low address
4254   // is aligned to page size (Note: base is usually not and we do not care).
4255   // We need to do this because caller code will assume stack low address is
4256   // page aligned and will place guard pages without checking.
4257   address low = bounds.base - bounds.size;
4258   address low_aligned = (address)align_up(low, os::vm_page_size());
4259   size_t s = bounds.base - low_aligned;
4260   return s;
4261 }
4262 
4263 extern char** environ;
4264 
4265 // Run the specified command in a separate process. Return its exit value,
4266 // or -1 on failure (e.g. can't fork a new process).
4267 // Unlike system(), this function can be called from signal handler. It
4268 // doesn't block SIGINT et al.
4269 int os::fork_and_exec(char* cmd) {
4270   char * argv[4] = {"sh", "-c", cmd, NULL};
4271 
4272   pid_t pid = fork();
4273 
4274   if (pid < 0) {
4275     // fork failed
4276     return -1;
4277 
4278   } else if (pid == 0) {
4279     // child process
4280 
4281     // Try to be consistent with system(), which uses "/usr/bin/sh" on AIX.
4282     execve("/usr/bin/sh", argv, environ);
4283 
4284     // execve failed
4285     _exit(-1);
4286 
4287   } else {
4288     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4289     // care about the actual exit code, for now.
4290 
4291     int status;
4292 
4293     // Wait for the child process to exit. This returns immediately if
4294     // the child has already exited. */
4295     while (waitpid(pid, &status, 0) < 0) {
4296       switch (errno) {
4297         case ECHILD: return 0;
4298         case EINTR: break;
4299         default: return -1;
4300       }
4301     }
4302 
4303     if (WIFEXITED(status)) {
4304       // The child exited normally; get its exit code.
4305       return WEXITSTATUS(status);
4306     } else if (WIFSIGNALED(status)) {
4307       // The child exited because of a signal.
4308       // The best value to return is 0x80 + signal number,
4309       // because that is what all Unix shells do, and because
4310       // it allows callers to distinguish between process exit and
4311       // process death by signal.
4312       return 0x80 + WTERMSIG(status);
4313     } else {
4314       // Unknown exit code; pass it through.
4315       return status;
4316     }
4317   }
4318   return -1;
4319 }
4320 
4321 // Get the default path to the core file
4322 // Returns the length of the string
4323 int os::get_core_path(char* buffer, size_t bufferSize) {
4324   const char* p = get_current_directory(buffer, bufferSize);
4325 
4326   if (p == NULL) {
4327     assert(p != NULL, "failed to get current directory");
4328     return 0;
4329   }
4330 
4331   jio_snprintf(buffer, bufferSize, "%s/core or core.%d",
4332                                                p, current_process_id());
4333 
4334   return strlen(buffer);
4335 }
4336 
4337 #ifndef PRODUCT
4338 void TestReserveMemorySpecial_test() {
4339   // No tests available for this platform
4340 }
4341 #endif
4342 
4343 bool os::start_debugging(char *buf, int buflen) {
4344   int len = (int)strlen(buf);
4345   char *p = &buf[len];
4346 
4347   jio_snprintf(p, buflen -len,
4348                  "\n\n"
4349                  "Do you want to debug the problem?\n\n"
4350                  "To debug, run 'dbx -a %d'; then switch to thread tid " INTX_FORMAT ", k-tid " INTX_FORMAT "\n"
4351                  "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
4352                  "Otherwise, press RETURN to abort...",
4353                  os::current_process_id(),
4354                  os::current_thread_id(), thread_self());
4355 
4356   bool yes = os::message_box("Unexpected Error", buf);
4357 
4358   if (yes) {
4359     // yes, user asked VM to launch debugger
4360     jio_snprintf(buf, buflen, "dbx -a %d", os::current_process_id());
4361 
4362     os::fork_and_exec(buf);
4363     yes = false;
4364   }
4365   return yes;
4366 }
4367 
4368 static inline time_t get_mtime(const char* filename) {
4369   struct stat st;
4370   int ret = os::stat(filename, &st);
4371   assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
4372   return st.st_mtime;
4373 }
4374 
4375 int os::compare_file_modified_times(const char* file1, const char* file2) {
4376   time_t t1 = get_mtime(file1);
4377   time_t t2 = get_mtime(file2);
4378   return t1 - t2;
4379 }