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.inline.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.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     if (!set_boot_path('/', ':')) {
 580       vm_exit_during_initialization("Failed setting boot class path.", NULL);
 581     }
 582   }
 583 
 584   // Where to look for native libraries.
 585 
 586   // On Aix we get the user setting of LIBPATH.
 587   // Eventually, all the library path setting will be done here.
 588   // Get the user setting of LIBPATH.
 589   const char *v = ::getenv("LIBPATH");
 590   const char *v_colon = ":";
 591   if (v == NULL) { v = ""; v_colon = ""; }
 592 
 593   // Concatenate user and invariant part of ld_library_path.
 594   // That's +1 for the colon and +1 for the trailing '\0'.
 595   char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, strlen(v) + 1 + sizeof(DEFAULT_LIBPATH) + 1, mtInternal);
 596   sprintf(ld_library_path, "%s%s" DEFAULT_LIBPATH, v, v_colon);
 597   Arguments::set_library_path(ld_library_path);
 598   FREE_C_HEAP_ARRAY(char, ld_library_path);
 599 
 600   // Extensions directories.
 601   sprintf(buf, "%s" EXTENSIONS_DIR, Arguments::get_java_home());
 602   Arguments::set_ext_dirs(buf);
 603 
 604   FREE_C_HEAP_ARRAY(char, buf);
 605 
 606 #undef DEFAULT_LIBPATH
 607 #undef EXTENSIONS_DIR
 608 }
 609 
 610 ////////////////////////////////////////////////////////////////////////////////
 611 // breakpoint support
 612 
 613 void os::breakpoint() {
 614   BREAKPOINT;
 615 }
 616 
 617 extern "C" void breakpoint() {
 618   // use debugger to set breakpoint here
 619 }
 620 
 621 ////////////////////////////////////////////////////////////////////////////////
 622 // signal support
 623 
 624 debug_only(static bool signal_sets_initialized = false);
 625 static sigset_t unblocked_sigs, vm_sigs;
 626 
 627 void os::Aix::signal_sets_init() {
 628   // Should also have an assertion stating we are still single-threaded.
 629   assert(!signal_sets_initialized, "Already initialized");
 630   // Fill in signals that are necessarily unblocked for all threads in
 631   // the VM. Currently, we unblock the following signals:
 632   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 633   //                         by -Xrs (=ReduceSignalUsage));
 634   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 635   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 636   // the dispositions or masks wrt these signals.
 637   // Programs embedding the VM that want to use the above signals for their
 638   // own purposes must, at this time, use the "-Xrs" option to prevent
 639   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 640   // (See bug 4345157, and other related bugs).
 641   // In reality, though, unblocking these signals is really a nop, since
 642   // these signals are not blocked by default.
 643   sigemptyset(&unblocked_sigs);
 644   sigaddset(&unblocked_sigs, SIGILL);
 645   sigaddset(&unblocked_sigs, SIGSEGV);
 646   sigaddset(&unblocked_sigs, SIGBUS);
 647   sigaddset(&unblocked_sigs, SIGFPE);
 648   sigaddset(&unblocked_sigs, SIGTRAP);
 649   sigaddset(&unblocked_sigs, SR_signum);
 650 
 651   if (!ReduceSignalUsage) {
 652    if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 653      sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 654    }
 655    if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 656      sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 657    }
 658    if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 659      sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 660    }
 661   }
 662   // Fill in signals that are blocked by all but the VM thread.
 663   sigemptyset(&vm_sigs);
 664   if (!ReduceSignalUsage)
 665     sigaddset(&vm_sigs, BREAK_SIGNAL);
 666   debug_only(signal_sets_initialized = true);
 667 }
 668 
 669 // These are signals that are unblocked while a thread is running Java.
 670 // (For some reason, they get blocked by default.)
 671 sigset_t* os::Aix::unblocked_signals() {
 672   assert(signal_sets_initialized, "Not initialized");
 673   return &unblocked_sigs;
 674 }
 675 
 676 // These are the signals that are blocked while a (non-VM) thread is
 677 // running Java. Only the VM thread handles these signals.
 678 sigset_t* os::Aix::vm_signals() {
 679   assert(signal_sets_initialized, "Not initialized");
 680   return &vm_sigs;
 681 }
 682 
 683 void os::Aix::hotspot_sigmask(Thread* thread) {
 684 
 685   //Save caller's signal mask before setting VM signal mask
 686   sigset_t caller_sigmask;
 687   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 688 
 689   OSThread* osthread = thread->osthread();
 690   osthread->set_caller_sigmask(caller_sigmask);
 691 
 692   pthread_sigmask(SIG_UNBLOCK, os::Aix::unblocked_signals(), NULL);
 693 
 694   if (!ReduceSignalUsage) {
 695     if (thread->is_VM_thread()) {
 696       // Only the VM thread handles BREAK_SIGNAL ...
 697       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 698     } else {
 699       // ... all other threads block BREAK_SIGNAL
 700       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 701     }
 702   }
 703 }
 704 
 705 // retrieve memory information.
 706 // Returns false if something went wrong;
 707 // content of pmi undefined in this case.
 708 bool os::Aix::get_meminfo(meminfo_t* pmi) {
 709 
 710   assert(pmi, "get_meminfo: invalid parameter");
 711 
 712   memset(pmi, 0, sizeof(meminfo_t));
 713 
 714   if (os::Aix::on_pase()) {
 715     // On PASE, use the libo4 porting library.
 716 
 717     unsigned long long virt_total = 0;
 718     unsigned long long real_total = 0;
 719     unsigned long long real_free = 0;
 720     unsigned long long pgsp_total = 0;
 721     unsigned long long pgsp_free = 0;
 722     if (libo4::get_memory_info(&virt_total, &real_total, &real_free, &pgsp_total, &pgsp_free)) {
 723       pmi->virt_total = virt_total;
 724       pmi->real_total = real_total;
 725       pmi->real_free = real_free;
 726       pmi->pgsp_total = pgsp_total;
 727       pmi->pgsp_free = pgsp_free;
 728       return true;
 729     }
 730     return false;
 731 
 732   } else {
 733 
 734     // On AIX, I use the (dynamically loaded) perfstat library to retrieve memory statistics
 735     // See:
 736     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 737     //        ?topic=/com.ibm.aix.basetechref/doc/basetrf1/perfstat_memtot.htm
 738     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 739     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 740 
 741     perfstat_memory_total_t psmt;
 742     memset (&psmt, '\0', sizeof(psmt));
 743     const int rc = libperfstat::perfstat_memory_total(NULL, &psmt, sizeof(psmt), 1);
 744     if (rc == -1) {
 745       trcVerbose("perfstat_memory_total() failed (errno=%d)", errno);
 746       assert(0, "perfstat_memory_total() failed");
 747       return false;
 748     }
 749 
 750     assert(rc == 1, "perfstat_memory_total() - weird return code");
 751 
 752     // excerpt from
 753     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 754     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 755     // The fields of perfstat_memory_total_t:
 756     // u_longlong_t virt_total         Total virtual memory (in 4 KB pages).
 757     // u_longlong_t real_total         Total real memory (in 4 KB pages).
 758     // u_longlong_t real_free          Free real memory (in 4 KB pages).
 759     // u_longlong_t pgsp_total         Total paging space (in 4 KB pages).
 760     // u_longlong_t pgsp_free          Free paging space (in 4 KB pages).
 761 
 762     pmi->virt_total = psmt.virt_total * 4096;
 763     pmi->real_total = psmt.real_total * 4096;
 764     pmi->real_free = psmt.real_free * 4096;
 765     pmi->pgsp_total = psmt.pgsp_total * 4096;
 766     pmi->pgsp_free = psmt.pgsp_free * 4096;
 767 
 768     return true;
 769 
 770   }
 771 } // end os::Aix::get_meminfo
 772 
 773 //////////////////////////////////////////////////////////////////////////////
 774 // create new thread
 775 
 776 // Thread start routine for all newly created threads
 777 static void *thread_native_entry(Thread *thread) {
 778 
 779   // find out my own stack dimensions
 780   {
 781     // actually, this should do exactly the same as thread->record_stack_base_and_size...
 782     thread->set_stack_base(os::current_stack_base());
 783     thread->set_stack_size(os::current_stack_size());
 784   }
 785 
 786   const pthread_t pthread_id = ::pthread_self();
 787   const tid_t kernel_thread_id = ::thread_self();
 788 
 789   LogTarget(Info, os, thread) lt;
 790   if (lt.is_enabled()) {
 791     address low_address = thread->stack_end();
 792     address high_address = thread->stack_base();
 793     lt.print("Thread is alive (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT
 794              ", stack [" PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "k using %uk pages)).",
 795              os::current_thread_id(), (uintx) kernel_thread_id, low_address, high_address,
 796              (high_address - low_address) / K, os::Aix::query_pagesize(low_address) / K);
 797   }
 798 
 799   // Normally, pthread stacks on AIX live in the data segment (are allocated with malloc()
 800   // by the pthread library). In rare cases, this may not be the case, e.g. when third-party
 801   // tools hook pthread_create(). In this case, we may run into problems establishing
 802   // guard pages on those stacks, because the stacks may reside in memory which is not
 803   // protectable (shmated).
 804   if (thread->stack_base() > ::sbrk(0)) {
 805     log_warning(os, thread)("Thread stack not in data segment.");
 806   }
 807 
 808   // Try to randomize the cache line index of hot stack frames.
 809   // This helps when threads of the same stack traces evict each other's
 810   // cache lines. The threads can be either from the same JVM instance, or
 811   // from different JVM instances. The benefit is especially true for
 812   // processors with hyperthreading technology.
 813 
 814   static int counter = 0;
 815   int pid = os::current_process_id();
 816   alloca(((pid ^ counter++) & 7) * 128);
 817 
 818   thread->initialize_thread_current();
 819 
 820   OSThread* osthread = thread->osthread();
 821 
 822   // Thread_id is pthread id.
 823   osthread->set_thread_id(pthread_id);
 824 
 825   // .. but keep kernel thread id too for diagnostics
 826   osthread->set_kernel_thread_id(kernel_thread_id);
 827 
 828   // Initialize signal mask for this thread.
 829   os::Aix::hotspot_sigmask(thread);
 830 
 831   // Initialize floating point control register.
 832   os::Aix::init_thread_fpu_state();
 833 
 834   assert(osthread->get_state() == RUNNABLE, "invalid os thread state");
 835 
 836   // Call one more level start routine.
 837   thread->run();
 838 
 839   log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 840     os::current_thread_id(), (uintx) kernel_thread_id);
 841 
 842   // If a thread has not deleted itself ("delete this") as part of its
 843   // termination sequence, we have to ensure thread-local-storage is
 844   // cleared before we actually terminate. No threads should ever be
 845   // deleted asynchronously with respect to their termination.
 846   if (Thread::current_or_null_safe() != NULL) {
 847     assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
 848     thread->clear_thread_current();
 849   }
 850 
 851   return 0;
 852 }
 853 
 854 bool os::create_thread(Thread* thread, ThreadType thr_type,
 855                        size_t req_stack_size) {
 856 
 857   assert(thread->osthread() == NULL, "caller responsible");
 858 
 859   // Allocate the OSThread object.
 860   OSThread* osthread = new OSThread(NULL, NULL);
 861   if (osthread == NULL) {
 862     return false;
 863   }
 864 
 865   // Set the correct thread state.
 866   osthread->set_thread_type(thr_type);
 867 
 868   // Initial state is ALLOCATED but not INITIALIZED
 869   osthread->set_state(ALLOCATED);
 870 
 871   thread->set_osthread(osthread);
 872 
 873   // Init thread attributes.
 874   pthread_attr_t attr;
 875   pthread_attr_init(&attr);
 876   guarantee(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0, "???");
 877 
 878   // Make sure we run in 1:1 kernel-user-thread mode.
 879   if (os::Aix::on_aix()) {
 880     guarantee(pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) == 0, "???");
 881     guarantee(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0, "???");
 882   }
 883 
 884   // Start in suspended state, and in os::thread_start, wake the thread up.
 885   guarantee(pthread_attr_setsuspendstate_np(&attr, PTHREAD_CREATE_SUSPENDED_NP) == 0, "???");
 886 
 887   // Calculate stack size if it's not specified by caller.
 888   size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
 889 
 890   // JDK-8187028: It was observed that on some configurations (4K backed thread stacks)
 891   // the real thread stack size may be smaller than the requested stack size, by as much as 64K.
 892   // This very much looks like a pthread lib error. As a workaround, increase the stack size
 893   // by 64K for small thread stacks (arbitrarily choosen to be < 4MB)
 894   if (stack_size < 4096 * K) {
 895     stack_size += 64 * K;
 896   }
 897 
 898   // On Aix, pthread_attr_setstacksize fails with huge values and leaves the
 899   // thread size in attr unchanged. If this is the minimal stack size as set
 900   // by pthread_attr_init this leads to crashes after thread creation. E.g. the
 901   // guard pages might not fit on the tiny stack created.
 902   int ret = pthread_attr_setstacksize(&attr, stack_size);
 903   if (ret != 0) {
 904     log_warning(os, thread)("The %sthread stack size specified is invalid: " SIZE_FORMAT "k",
 905                             (thr_type == compiler_thread) ? "compiler " : ((thr_type == java_thread) ? "" : "VM "),
 906                             stack_size / K);
 907     thread->set_osthread(NULL);
 908     delete osthread;
 909     return false;
 910   }
 911 
 912   // Save some cycles and a page by disabling OS guard pages where we have our own
 913   // VM guard pages (in java threads). For other threads, keep system default guard
 914   // pages in place.
 915   if (thr_type == java_thread || thr_type == compiler_thread) {
 916     ret = pthread_attr_setguardsize(&attr, 0);
 917   }
 918 
 919   pthread_t tid = 0;
 920   if (ret == 0) {
 921     ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
 922   }
 923 
 924   if (ret == 0) {
 925     char buf[64];
 926     log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
 927       (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 928   } else {
 929     char buf[64];
 930     log_warning(os, thread)("Failed to start thread - pthread_create failed (%d=%s) for attributes: %s.",
 931       ret, os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 932   }
 933 
 934   pthread_attr_destroy(&attr);
 935 
 936   if (ret != 0) {
 937     // Need to clean up stuff we've allocated so far.
 938     thread->set_osthread(NULL);
 939     delete osthread;
 940     return false;
 941   }
 942 
 943   // OSThread::thread_id is the pthread id.
 944   osthread->set_thread_id(tid);
 945 
 946   return true;
 947 }
 948 
 949 /////////////////////////////////////////////////////////////////////////////
 950 // attach existing thread
 951 
 952 // bootstrap the main thread
 953 bool os::create_main_thread(JavaThread* thread) {
 954   assert(os::Aix::_main_thread == pthread_self(), "should be called inside main thread");
 955   return create_attached_thread(thread);
 956 }
 957 
 958 bool os::create_attached_thread(JavaThread* thread) {
 959 #ifdef ASSERT
 960     thread->verify_not_published();
 961 #endif
 962 
 963   // Allocate the OSThread object
 964   OSThread* osthread = new OSThread(NULL, NULL);
 965 
 966   if (osthread == NULL) {
 967     return false;
 968   }
 969 
 970   const pthread_t pthread_id = ::pthread_self();
 971   const tid_t kernel_thread_id = ::thread_self();
 972 
 973   // OSThread::thread_id is the pthread id.
 974   osthread->set_thread_id(pthread_id);
 975 
 976   // .. but keep kernel thread id too for diagnostics
 977   osthread->set_kernel_thread_id(kernel_thread_id);
 978 
 979   // initialize floating point control register
 980   os::Aix::init_thread_fpu_state();
 981 
 982   // Initial thread state is RUNNABLE
 983   osthread->set_state(RUNNABLE);
 984 
 985   thread->set_osthread(osthread);
 986 
 987   if (UseNUMA) {
 988     int lgrp_id = os::numa_get_group_id();
 989     if (lgrp_id != -1) {
 990       thread->set_lgrp_id(lgrp_id);
 991     }
 992   }
 993 
 994   // initialize signal mask for this thread
 995   // and save the caller's signal mask
 996   os::Aix::hotspot_sigmask(thread);
 997 
 998   log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 999     os::current_thread_id(), (uintx) kernel_thread_id);
1000 
1001   return true;
1002 }
1003 
1004 void os::pd_start_thread(Thread* thread) {
1005   int status = pthread_continue_np(thread->osthread()->pthread_id());
1006   assert(status == 0, "thr_continue failed");
1007 }
1008 
1009 // Free OS resources related to the OSThread
1010 void os::free_thread(OSThread* osthread) {
1011   assert(osthread != NULL, "osthread not set");
1012 
1013   // We are told to free resources of the argument thread,
1014   // but we can only really operate on the current thread.
1015   assert(Thread::current()->osthread() == osthread,
1016          "os::free_thread but not current thread");
1017 
1018   // Restore caller's signal mask
1019   sigset_t sigmask = osthread->caller_sigmask();
1020   pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1021 
1022   delete osthread;
1023 }
1024 
1025 ////////////////////////////////////////////////////////////////////////////////
1026 // time support
1027 
1028 // Time since start-up in seconds to a fine granularity.
1029 // Used by VMSelfDestructTimer and the MemProfiler.
1030 double os::elapsedTime() {
1031   return (double)(os::elapsed_counter()) * 0.000001;
1032 }
1033 
1034 jlong os::elapsed_counter() {
1035   timeval time;
1036   int status = gettimeofday(&time, NULL);
1037   return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1038 }
1039 
1040 jlong os::elapsed_frequency() {
1041   return (1000 * 1000);
1042 }
1043 
1044 bool os::supports_vtime() { return true; }
1045 bool os::enable_vtime()   { return false; }
1046 bool os::vtime_enabled()  { return false; }
1047 
1048 double os::elapsedVTime() {
1049   struct rusage usage;
1050   int retval = getrusage(RUSAGE_THREAD, &usage);
1051   if (retval == 0) {
1052     return usage.ru_utime.tv_sec + usage.ru_stime.tv_sec + (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000.0 * 1000);
1053   } else {
1054     // better than nothing, but not much
1055     return elapsedTime();
1056   }
1057 }
1058 
1059 jlong os::javaTimeMillis() {
1060   timeval time;
1061   int status = gettimeofday(&time, NULL);
1062   assert(status != -1, "aix error at gettimeofday()");
1063   return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1064 }
1065 
1066 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1067   timeval time;
1068   int status = gettimeofday(&time, NULL);
1069   assert(status != -1, "aix error at gettimeofday()");
1070   seconds = jlong(time.tv_sec);
1071   nanos = jlong(time.tv_usec) * 1000;
1072 }
1073 
1074 // We use mread_real_time here.
1075 // On AIX: If the CPU has a time register, the result will be RTC_POWER and
1076 // it has to be converted to real time. AIX documentations suggests to do
1077 // this unconditionally, so we do it.
1078 //
1079 // See: https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf2/read_real_time.htm
1080 //
1081 // On PASE: mread_real_time will always return RTC_POWER_PC data, so no
1082 // conversion is necessary. However, mread_real_time will not return
1083 // monotonic results but merely matches read_real_time. So we need a tweak
1084 // to ensure monotonic results.
1085 //
1086 // For PASE no public documentation exists, just word by IBM
1087 jlong os::javaTimeNanos() {
1088   timebasestruct_t time;
1089   int rc = mread_real_time(&time, TIMEBASE_SZ);
1090   if (os::Aix::on_pase()) {
1091     assert(rc == RTC_POWER, "expected time format RTC_POWER from mread_real_time in PASE");
1092     jlong now = jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1093     jlong prev = max_real_time;
1094     if (now <= prev) {
1095       return prev;   // same or retrograde time;
1096     }
1097     jlong obsv = Atomic::cmpxchg(now, &max_real_time, prev);
1098     assert(obsv >= prev, "invariant");   // Monotonicity
1099     // If the CAS succeeded then we're done and return "now".
1100     // If the CAS failed and the observed value "obsv" is >= now then
1101     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1102     // some other thread raced this thread and installed a new value, in which case
1103     // we could either (a) retry the entire operation, (b) retry trying to install now
1104     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1105     // we might discard a higher "now" value in deference to a slightly lower but freshly
1106     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1107     // to (a) or (b) -- and greatly reduces coherence traffic.
1108     // We might also condition (c) on the magnitude of the delta between obsv and now.
1109     // Avoiding excessive CAS operations to hot RW locations is critical.
1110     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1111     return (prev == obsv) ? now : obsv;
1112   } else {
1113     if (rc != RTC_POWER) {
1114       rc = time_base_to_time(&time, TIMEBASE_SZ);
1115       assert(rc != -1, "error calling time_base_to_time()");
1116     }
1117     return jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1118   }
1119 }
1120 
1121 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1122   info_ptr->max_value = ALL_64_BITS;
1123   // mread_real_time() is monotonic (see 'os::javaTimeNanos()')
1124   info_ptr->may_skip_backward = false;
1125   info_ptr->may_skip_forward = false;
1126   info_ptr->kind = JVMTI_TIMER_ELAPSED;    // elapsed not CPU time
1127 }
1128 
1129 // Return the real, user, and system times in seconds from an
1130 // arbitrary fixed point in the past.
1131 bool os::getTimesSecs(double* process_real_time,
1132                       double* process_user_time,
1133                       double* process_system_time) {
1134   struct tms ticks;
1135   clock_t real_ticks = times(&ticks);
1136 
1137   if (real_ticks == (clock_t) (-1)) {
1138     return false;
1139   } else {
1140     double ticks_per_second = (double) clock_tics_per_sec;
1141     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1142     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1143     *process_real_time = ((double) real_ticks) / ticks_per_second;
1144 
1145     return true;
1146   }
1147 }
1148 
1149 char * os::local_time_string(char *buf, size_t buflen) {
1150   struct tm t;
1151   time_t long_time;
1152   time(&long_time);
1153   localtime_r(&long_time, &t);
1154   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1155                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1156                t.tm_hour, t.tm_min, t.tm_sec);
1157   return buf;
1158 }
1159 
1160 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1161   return localtime_r(clock, res);
1162 }
1163 
1164 ////////////////////////////////////////////////////////////////////////////////
1165 // runtime exit support
1166 
1167 // Note: os::shutdown() might be called very early during initialization, or
1168 // called from signal handler. Before adding something to os::shutdown(), make
1169 // sure it is async-safe and can handle partially initialized VM.
1170 void os::shutdown() {
1171 
1172   // allow PerfMemory to attempt cleanup of any persistent resources
1173   perfMemory_exit();
1174 
1175   // needs to remove object in file system
1176   AttachListener::abort();
1177 
1178   // flush buffered output, finish log files
1179   ostream_abort();
1180 
1181   // Check for abort hook
1182   abort_hook_t abort_hook = Arguments::abort_hook();
1183   if (abort_hook != NULL) {
1184     abort_hook();
1185   }
1186 }
1187 
1188 // Note: os::abort() might be called very early during initialization, or
1189 // called from signal handler. Before adding something to os::abort(), make
1190 // sure it is async-safe and can handle partially initialized VM.
1191 void os::abort(bool dump_core, void* siginfo, const void* context) {
1192   os::shutdown();
1193   if (dump_core) {
1194 #ifndef PRODUCT
1195     fdStream out(defaultStream::output_fd());
1196     out.print_raw("Current thread is ");
1197     char buf[16];
1198     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1199     out.print_raw_cr(buf);
1200     out.print_raw_cr("Dumping core ...");
1201 #endif
1202     ::abort(); // dump core
1203   }
1204 
1205   ::exit(1);
1206 }
1207 
1208 // Die immediately, no exit hook, no abort hook, no cleanup.
1209 void os::die() {
1210   ::abort();
1211 }
1212 
1213 intx os::current_thread_id() {
1214   return (intx)pthread_self();
1215 }
1216 
1217 int os::current_process_id() {
1218   return getpid();
1219 }
1220 
1221 // DLL functions
1222 
1223 const char* os::dll_file_extension() { return ".so"; }
1224 
1225 // This must be hard coded because it's the system's temporary
1226 // directory not the java application's temp directory, ala java.io.tmpdir.
1227 const char* os::get_temp_directory() { return "/tmp"; }
1228 
1229 // Check if addr is inside libjvm.so.
1230 bool os::address_is_in_vm(address addr) {
1231 
1232   // Input could be a real pc or a function pointer literal. The latter
1233   // would be a function descriptor residing in the data segment of a module.
1234   loaded_module_t lm;
1235   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL) {
1236     return lm.is_in_vm;
1237   } else if (LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
1238     return lm.is_in_vm;
1239   } else {
1240     return false;
1241   }
1242 
1243 }
1244 
1245 // Resolve an AIX function descriptor literal to a code pointer.
1246 // If the input is a valid code pointer to a text segment of a loaded module,
1247 //   it is returned unchanged.
1248 // If the input is a valid AIX function descriptor, it is resolved to the
1249 //   code entry point.
1250 // If the input is neither a valid function descriptor nor a valid code pointer,
1251 //   NULL is returned.
1252 static address resolve_function_descriptor_to_code_pointer(address p) {
1253 
1254   if (LoadedLibraries::find_for_text_address(p, NULL) != NULL) {
1255     // It is a real code pointer.
1256     return p;
1257   } else if (LoadedLibraries::find_for_data_address(p, NULL) != NULL) {
1258     // Pointer to data segment, potential function descriptor.
1259     address code_entry = (address)(((FunctionDescriptor*)p)->entry());
1260     if (LoadedLibraries::find_for_text_address(code_entry, NULL) != NULL) {
1261       // It is a function descriptor.
1262       return code_entry;
1263     }
1264   }
1265 
1266   return NULL;
1267 }
1268 
1269 bool os::dll_address_to_function_name(address addr, char *buf,
1270                                       int buflen, int *offset,
1271                                       bool demangle) {
1272   if (offset) {
1273     *offset = -1;
1274   }
1275   // Buf is not optional, but offset is optional.
1276   assert(buf != NULL, "sanity check");
1277   buf[0] = '\0';
1278 
1279   // Resolve function ptr literals first.
1280   addr = resolve_function_descriptor_to_code_pointer(addr);
1281   if (!addr) {
1282     return false;
1283   }
1284 
1285   return AixSymbols::get_function_name(addr, buf, buflen, offset, NULL, demangle);
1286 }
1287 
1288 bool os::dll_address_to_library_name(address addr, char* buf,
1289                                      int buflen, int* offset) {
1290   if (offset) {
1291     *offset = -1;
1292   }
1293   // Buf is not optional, but offset is optional.
1294   assert(buf != NULL, "sanity check");
1295   buf[0] = '\0';
1296 
1297   // Resolve function ptr literals first.
1298   addr = resolve_function_descriptor_to_code_pointer(addr);
1299   if (!addr) {
1300     return false;
1301   }
1302 
1303   return AixSymbols::get_module_name(addr, buf, buflen);
1304 }
1305 
1306 // Loads .dll/.so and in case of error it checks if .dll/.so was built
1307 // for the same architecture as Hotspot is running on.
1308 void *os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1309 
1310   if (ebuf && ebuflen > 0) {
1311     ebuf[0] = '\0';
1312     ebuf[ebuflen - 1] = '\0';
1313   }
1314 
1315   if (!filename || strlen(filename) == 0) {
1316     ::strncpy(ebuf, "dll_load: empty filename specified", ebuflen - 1);
1317     return NULL;
1318   }
1319 
1320   // RTLD_LAZY is currently not implemented. The dl is loaded immediately with all its dependants.
1321   void * result= ::dlopen(filename, RTLD_LAZY);
1322   if (result != NULL) {
1323     // Reload dll cache. Don't do this in signal handling.
1324     LoadedLibraries::reload();
1325     return result;
1326   } else {
1327     // error analysis when dlopen fails
1328     const char* const error_report = ::dlerror();
1329     if (error_report && ebuf && ebuflen > 0) {
1330       snprintf(ebuf, ebuflen - 1, "%s, LIBPATH=%s, LD_LIBRARY_PATH=%s : %s",
1331                filename, ::getenv("LIBPATH"), ::getenv("LD_LIBRARY_PATH"), error_report);
1332     }
1333   }
1334   return NULL;
1335 }
1336 
1337 void* os::dll_lookup(void* handle, const char* name) {
1338   void* res = dlsym(handle, name);
1339   return res;
1340 }
1341 
1342 void* os::get_default_process_handle() {
1343   return (void*)::dlopen(NULL, RTLD_LAZY);
1344 }
1345 
1346 void os::print_dll_info(outputStream *st) {
1347   st->print_cr("Dynamic libraries:");
1348   LoadedLibraries::print(st);
1349 }
1350 
1351 void os::get_summary_os_info(char* buf, size_t buflen) {
1352   // There might be something more readable than uname results for AIX.
1353   struct utsname name;
1354   uname(&name);
1355   snprintf(buf, buflen, "%s %s", name.release, name.version);
1356 }
1357 
1358 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1359   // Not yet implemented.
1360   return 0;
1361 }
1362 
1363 void os::print_os_info_brief(outputStream* st) {
1364   uint32_t ver = os::Aix::os_version();
1365   st->print_cr("AIX kernel version %u.%u.%u.%u",
1366                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1367 
1368   os::Posix::print_uname_info(st);
1369 
1370   // Linux uses print_libversion_info(st); here.
1371 }
1372 
1373 void os::print_os_info(outputStream* st) {
1374   st->print("OS:");
1375 
1376   st->print("uname:");
1377   struct utsname name;
1378   uname(&name);
1379   st->print(name.sysname); st->print(" ");
1380   st->print(name.nodename); st->print(" ");
1381   st->print(name.release); st->print(" ");
1382   st->print(name.version); st->print(" ");
1383   st->print(name.machine);
1384   st->cr();
1385 
1386   uint32_t ver = os::Aix::os_version();
1387   st->print_cr("AIX kernel version %u.%u.%u.%u",
1388                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1389 
1390   os::Posix::print_rlimit_info(st);
1391 
1392   // load average
1393   st->print("load average:");
1394   double loadavg[3] = {-1.L, -1.L, -1.L};
1395   os::loadavg(loadavg, 3);
1396   st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1397   st->cr();
1398 
1399   // print wpar info
1400   libperfstat::wparinfo_t wi;
1401   if (libperfstat::get_wparinfo(&wi)) {
1402     st->print_cr("wpar info");
1403     st->print_cr("name: %s", wi.name);
1404     st->print_cr("id:   %d", wi.wpar_id);
1405     st->print_cr("type: %s", (wi.app_wpar ? "application" : "system"));
1406   }
1407 
1408   // print partition info
1409   libperfstat::partitioninfo_t pi;
1410   if (libperfstat::get_partitioninfo(&pi)) {
1411     st->print_cr("partition info");
1412     st->print_cr(" name: %s", pi.name);
1413   }
1414 
1415 }
1416 
1417 void os::print_memory_info(outputStream* st) {
1418 
1419   st->print_cr("Memory:");
1420 
1421   st->print_cr("  Base page size (sysconf _SC_PAGESIZE):  %s",
1422     describe_pagesize(g_multipage_support.pagesize));
1423   st->print_cr("  Data page size (C-Heap, bss, etc):      %s",
1424     describe_pagesize(g_multipage_support.datapsize));
1425   st->print_cr("  Text page size:                         %s",
1426     describe_pagesize(g_multipage_support.textpsize));
1427   st->print_cr("  Thread stack page size (pthread):       %s",
1428     describe_pagesize(g_multipage_support.pthr_stack_pagesize));
1429   st->print_cr("  Default shared memory page size:        %s",
1430     describe_pagesize(g_multipage_support.shmpsize));
1431   st->print_cr("  Can use 64K pages dynamically with shared meory:  %s",
1432     (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
1433   st->print_cr("  Can use 16M pages dynamically with shared memory: %s",
1434     (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
1435   st->print_cr("  Multipage error: %d",
1436     g_multipage_support.error);
1437   st->cr();
1438   st->print_cr("  os::vm_page_size:       %s", describe_pagesize(os::vm_page_size()));
1439 
1440   // print out LDR_CNTRL because it affects the default page sizes
1441   const char* const ldr_cntrl = ::getenv("LDR_CNTRL");
1442   st->print_cr("  LDR_CNTRL=%s.", ldr_cntrl ? ldr_cntrl : "<unset>");
1443 
1444   // Print out EXTSHM because it is an unsupported setting.
1445   const char* const extshm = ::getenv("EXTSHM");
1446   st->print_cr("  EXTSHM=%s.", extshm ? extshm : "<unset>");
1447   if ( (strcmp(extshm, "on") == 0) || (strcmp(extshm, "ON") == 0) ) {
1448     st->print_cr("  *** Unsupported! Please remove EXTSHM from your environment! ***");
1449   }
1450 
1451   // Print out AIXTHREAD_GUARDPAGES because it affects the size of pthread stacks.
1452   const char* const aixthread_guardpages = ::getenv("AIXTHREAD_GUARDPAGES");
1453   st->print_cr("  AIXTHREAD_GUARDPAGES=%s.",
1454       aixthread_guardpages ? aixthread_guardpages : "<unset>");
1455   st->cr();
1456 
1457   os::Aix::meminfo_t mi;
1458   if (os::Aix::get_meminfo(&mi)) {
1459     if (os::Aix::on_aix()) {
1460       st->print_cr("physical total : " SIZE_FORMAT, mi.real_total);
1461       st->print_cr("physical free  : " SIZE_FORMAT, mi.real_free);
1462       st->print_cr("swap total     : " SIZE_FORMAT, mi.pgsp_total);
1463       st->print_cr("swap free      : " SIZE_FORMAT, mi.pgsp_free);
1464     } else {
1465       // PASE - Numbers are result of QWCRSSTS; they mean:
1466       // real_total: Sum of all system pools
1467       // real_free: always 0
1468       // pgsp_total: we take the size of the system ASP
1469       // pgsp_free: size of system ASP times percentage of system ASP unused
1470       st->print_cr("physical total     : " SIZE_FORMAT, mi.real_total);
1471       st->print_cr("system asp total   : " SIZE_FORMAT, mi.pgsp_total);
1472       st->print_cr("%% system asp used : %.2f",
1473         mi.pgsp_total ? (100.0f * (mi.pgsp_total - mi.pgsp_free) / mi.pgsp_total) : -1.0f);
1474     }
1475   }
1476   st->cr();
1477 
1478   // Print program break.
1479   st->print_cr("Program break at VM startup: " PTR_FORMAT ".", p2i(g_brk_at_startup));
1480   address brk_now = (address)::sbrk(0);
1481   if (brk_now != (address)-1) {
1482     st->print_cr("Program break now          : " PTR_FORMAT " (distance: " SIZE_FORMAT "k).",
1483                  p2i(brk_now), (size_t)((brk_now - g_brk_at_startup) / K));
1484   }
1485   st->print_cr("MaxExpectedDataSegmentSize    : " SIZE_FORMAT "k.", MaxExpectedDataSegmentSize / K);
1486   st->cr();
1487 
1488   // Print segments allocated with os::reserve_memory.
1489   st->print_cr("internal virtual memory regions used by vm:");
1490   vmembk_print_on(st);
1491 }
1492 
1493 // Get a string for the cpuinfo that is a summary of the cpu type
1494 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1495   // read _system_configuration.version
1496   switch (_system_configuration.version) {
1497   case PV_8:
1498     strncpy(buf, "Power PC 8", buflen);
1499     break;
1500   case PV_7:
1501     strncpy(buf, "Power PC 7", buflen);
1502     break;
1503   case PV_6_1:
1504     strncpy(buf, "Power PC 6 DD1.x", buflen);
1505     break;
1506   case PV_6:
1507     strncpy(buf, "Power PC 6", buflen);
1508     break;
1509   case PV_5:
1510     strncpy(buf, "Power PC 5", buflen);
1511     break;
1512   case PV_5_2:
1513     strncpy(buf, "Power PC 5_2", buflen);
1514     break;
1515   case PV_5_3:
1516     strncpy(buf, "Power PC 5_3", buflen);
1517     break;
1518   case PV_5_Compat:
1519     strncpy(buf, "PV_5_Compat", buflen);
1520     break;
1521   case PV_6_Compat:
1522     strncpy(buf, "PV_6_Compat", buflen);
1523     break;
1524   case PV_7_Compat:
1525     strncpy(buf, "PV_7_Compat", buflen);
1526     break;
1527   case PV_8_Compat:
1528     strncpy(buf, "PV_8_Compat", buflen);
1529     break;
1530   default:
1531     strncpy(buf, "unknown", buflen);
1532   }
1533 }
1534 
1535 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1536   // Nothing to do beyond of what os::print_cpu_info() does.
1537 }
1538 
1539 static void print_signal_handler(outputStream* st, int sig,
1540                                  char* buf, size_t buflen);
1541 
1542 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1543   st->print_cr("Signal Handlers:");
1544   print_signal_handler(st, SIGSEGV, buf, buflen);
1545   print_signal_handler(st, SIGBUS , buf, buflen);
1546   print_signal_handler(st, SIGFPE , buf, buflen);
1547   print_signal_handler(st, SIGPIPE, buf, buflen);
1548   print_signal_handler(st, SIGXFSZ, buf, buflen);
1549   print_signal_handler(st, SIGILL , buf, buflen);
1550   print_signal_handler(st, SR_signum, buf, buflen);
1551   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1552   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1553   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1554   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1555   print_signal_handler(st, SIGTRAP, buf, buflen);
1556   // We also want to know if someone else adds a SIGDANGER handler because
1557   // that will interfere with OOM killling.
1558   print_signal_handler(st, SIGDANGER, buf, buflen);
1559 }
1560 
1561 static char saved_jvm_path[MAXPATHLEN] = {0};
1562 
1563 // Find the full path to the current module, libjvm.so.
1564 void os::jvm_path(char *buf, jint buflen) {
1565   // Error checking.
1566   if (buflen < MAXPATHLEN) {
1567     assert(false, "must use a large-enough buffer");
1568     buf[0] = '\0';
1569     return;
1570   }
1571   // Lazy resolve the path to current module.
1572   if (saved_jvm_path[0] != 0) {
1573     strcpy(buf, saved_jvm_path);
1574     return;
1575   }
1576 
1577   Dl_info dlinfo;
1578   int ret = dladdr(CAST_FROM_FN_PTR(void *, os::jvm_path), &dlinfo);
1579   assert(ret != 0, "cannot locate libjvm");
1580   char* rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1581   assert(rp != NULL, "error in realpath(): maybe the 'path' argument is too long?");
1582 
1583   if (Arguments::sun_java_launcher_is_altjvm()) {
1584     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1585     // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
1586     // If "/jre/lib/" appears at the right place in the string, then
1587     // assume we are installed in a JDK and we're done. Otherwise, check
1588     // for a JAVA_HOME environment variable and fix up the path so it
1589     // looks like libjvm.so is installed there (append a fake suffix
1590     // hotspot/libjvm.so).
1591     const char *p = buf + strlen(buf) - 1;
1592     for (int count = 0; p > buf && count < 4; ++count) {
1593       for (--p; p > buf && *p != '/'; --p)
1594         /* empty */ ;
1595     }
1596 
1597     if (strncmp(p, "/jre/lib/", 9) != 0) {
1598       // Look for JAVA_HOME in the environment.
1599       char* java_home_var = ::getenv("JAVA_HOME");
1600       if (java_home_var != NULL && java_home_var[0] != 0) {
1601         char* jrelib_p;
1602         int len;
1603 
1604         // Check the current module name "libjvm.so".
1605         p = strrchr(buf, '/');
1606         if (p == NULL) {
1607           return;
1608         }
1609         assert(strstr(p, "/libjvm") == p, "invalid library name");
1610 
1611         rp = os::Posix::realpath(java_home_var, buf, buflen);
1612         if (rp == NULL) {
1613           return;
1614         }
1615 
1616         // determine if this is a legacy image or modules image
1617         // modules image doesn't have "jre" subdirectory
1618         len = strlen(buf);
1619         assert(len < buflen, "Ran out of buffer room");
1620         jrelib_p = buf + len;
1621         snprintf(jrelib_p, buflen-len, "/jre/lib");
1622         if (0 != access(buf, F_OK)) {
1623           snprintf(jrelib_p, buflen-len, "/lib");
1624         }
1625 
1626         if (0 == access(buf, F_OK)) {
1627           // Use current module name "libjvm.so"
1628           len = strlen(buf);
1629           snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
1630         } else {
1631           // Go back to path of .so
1632           rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1633           if (rp == NULL) {
1634             return;
1635           }
1636         }
1637       }
1638     }
1639   }
1640 
1641   strncpy(saved_jvm_path, buf, sizeof(saved_jvm_path));
1642   saved_jvm_path[sizeof(saved_jvm_path) - 1] = '\0';
1643 }
1644 
1645 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1646   // no prefix required, not even "_"
1647 }
1648 
1649 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1650   // no suffix required
1651 }
1652 
1653 ////////////////////////////////////////////////////////////////////////////////
1654 // sun.misc.Signal support
1655 
1656 static volatile jint sigint_count = 0;
1657 
1658 static void
1659 UserHandler(int sig, void *siginfo, void *context) {
1660   // 4511530 - sem_post is serialized and handled by the manager thread. When
1661   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1662   // don't want to flood the manager thread with sem_post requests.
1663   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1664     return;
1665 
1666   // Ctrl-C is pressed during error reporting, likely because the error
1667   // handler fails to abort. Let VM die immediately.
1668   if (sig == SIGINT && VMError::is_error_reported()) {
1669     os::die();
1670   }
1671 
1672   os::signal_notify(sig);
1673 }
1674 
1675 void* os::user_handler() {
1676   return CAST_FROM_FN_PTR(void*, UserHandler);
1677 }
1678 
1679 extern "C" {
1680   typedef void (*sa_handler_t)(int);
1681   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1682 }
1683 
1684 void* os::signal(int signal_number, void* handler) {
1685   struct sigaction sigAct, oldSigAct;
1686 
1687   sigfillset(&(sigAct.sa_mask));
1688 
1689   // Do not block out synchronous signals in the signal handler.
1690   // Blocking synchronous signals only makes sense if you can really
1691   // be sure that those signals won't happen during signal handling,
1692   // when the blocking applies. Normal signal handlers are lean and
1693   // do not cause signals. But our signal handlers tend to be "risky"
1694   // - secondary SIGSEGV, SIGILL, SIGBUS' may and do happen.
1695   // On AIX, PASE there was a case where a SIGSEGV happened, followed
1696   // by a SIGILL, which was blocked due to the signal mask. The process
1697   // just hung forever. Better to crash from a secondary signal than to hang.
1698   sigdelset(&(sigAct.sa_mask), SIGSEGV);
1699   sigdelset(&(sigAct.sa_mask), SIGBUS);
1700   sigdelset(&(sigAct.sa_mask), SIGILL);
1701   sigdelset(&(sigAct.sa_mask), SIGFPE);
1702   sigdelset(&(sigAct.sa_mask), SIGTRAP);
1703 
1704   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1705 
1706   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1707 
1708   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1709     // -1 means registration failed
1710     return (void *)-1;
1711   }
1712 
1713   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1714 }
1715 
1716 void os::signal_raise(int signal_number) {
1717   ::raise(signal_number);
1718 }
1719 
1720 //
1721 // The following code is moved from os.cpp for making this
1722 // code platform specific, which it is by its very nature.
1723 //
1724 
1725 // Will be modified when max signal is changed to be dynamic
1726 int os::sigexitnum_pd() {
1727   return NSIG;
1728 }
1729 
1730 // a counter for each possible signal value
1731 static volatile jint pending_signals[NSIG+1] = { 0 };
1732 
1733 // Wrapper functions for: sem_init(), sem_post(), sem_wait()
1734 // On AIX, we use sem_init(), sem_post(), sem_wait()
1735 // On Pase, we need to use msem_lock() and msem_unlock(), because Posix Semaphores
1736 // do not seem to work at all on PASE (unimplemented, will cause SIGILL).
1737 // Note that just using msem_.. APIs for both PASE and AIX is not an option either, as
1738 // on AIX, msem_..() calls are suspected of causing problems.
1739 static sem_t sig_sem;
1740 static msemaphore* p_sig_msem = 0;
1741 
1742 static void local_sem_init() {
1743   if (os::Aix::on_aix()) {
1744     int rc = ::sem_init(&sig_sem, 0, 0);
1745     guarantee(rc != -1, "sem_init failed");
1746   } else {
1747     // Memory semaphores must live in shared mem.
1748     guarantee0(p_sig_msem == NULL);
1749     p_sig_msem = (msemaphore*)os::reserve_memory(sizeof(msemaphore), NULL);
1750     guarantee(p_sig_msem, "Cannot allocate memory for memory semaphore");
1751     guarantee(::msem_init(p_sig_msem, 0) == p_sig_msem, "msem_init failed");
1752   }
1753 }
1754 
1755 static void local_sem_post() {
1756   static bool warn_only_once = false;
1757   if (os::Aix::on_aix()) {
1758     int rc = ::sem_post(&sig_sem);
1759     if (rc == -1 && !warn_only_once) {
1760       trcVerbose("sem_post failed (errno = %d, %s)", errno, os::errno_name(errno));
1761       warn_only_once = true;
1762     }
1763   } else {
1764     guarantee0(p_sig_msem != NULL);
1765     int rc = ::msem_unlock(p_sig_msem, 0);
1766     if (rc == -1 && !warn_only_once) {
1767       trcVerbose("msem_unlock failed (errno = %d, %s)", errno, os::errno_name(errno));
1768       warn_only_once = true;
1769     }
1770   }
1771 }
1772 
1773 static void local_sem_wait() {
1774   static bool warn_only_once = false;
1775   if (os::Aix::on_aix()) {
1776     int rc = ::sem_wait(&sig_sem);
1777     if (rc == -1 && !warn_only_once) {
1778       trcVerbose("sem_wait failed (errno = %d, %s)", errno, os::errno_name(errno));
1779       warn_only_once = true;
1780     }
1781   } else {
1782     guarantee0(p_sig_msem != NULL); // must init before use
1783     int rc = ::msem_lock(p_sig_msem, 0);
1784     if (rc == -1 && !warn_only_once) {
1785       trcVerbose("msem_lock failed (errno = %d, %s)", errno, os::errno_name(errno));
1786       warn_only_once = true;
1787     }
1788   }
1789 }
1790 
1791 static void jdk_misc_signal_init() {
1792   // Initialize signal structures
1793   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
1794 
1795   // Initialize signal semaphore
1796   local_sem_init();
1797 }
1798 
1799 void os::signal_notify(int sig) {
1800   Atomic::inc(&pending_signals[sig]);
1801   local_sem_post();
1802 }
1803 
1804 static int check_pending_signals() {
1805   Atomic::store(0, &sigint_count);
1806   for (;;) {
1807     for (int i = 0; i < NSIG + 1; i++) {
1808       jint n = pending_signals[i];
1809       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
1810         return i;
1811       }
1812     }
1813     JavaThread *thread = JavaThread::current();
1814     ThreadBlockInVM tbivm(thread);
1815 
1816     bool threadIsSuspended;
1817     do {
1818       thread->set_suspend_equivalent();
1819       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1820 
1821       local_sem_wait();
1822 
1823       // were we externally suspended while we were waiting?
1824       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
1825       if (threadIsSuspended) {
1826         //
1827         // The semaphore has been incremented, but while we were waiting
1828         // another thread suspended us. We don't want to continue running
1829         // while suspended because that would surprise the thread that
1830         // suspended us.
1831         //
1832 
1833         local_sem_post();
1834 
1835         thread->java_suspend_self();
1836       }
1837     } while (threadIsSuspended);
1838   }
1839 }
1840 
1841 int os::signal_wait() {
1842   return check_pending_signals();
1843 }
1844 
1845 ////////////////////////////////////////////////////////////////////////////////
1846 // Virtual Memory
1847 
1848 // We need to keep small simple bookkeeping for os::reserve_memory and friends.
1849 
1850 #define VMEM_MAPPED  1
1851 #define VMEM_SHMATED 2
1852 
1853 struct vmembk_t {
1854   int type;         // 1 - mmap, 2 - shmat
1855   char* addr;
1856   size_t size;      // Real size, may be larger than usersize.
1857   size_t pagesize;  // page size of area
1858   vmembk_t* next;
1859 
1860   bool contains_addr(char* p) const {
1861     return p >= addr && p < (addr + size);
1862   }
1863 
1864   bool contains_range(char* p, size_t s) const {
1865     return contains_addr(p) && contains_addr(p + s - 1);
1866   }
1867 
1868   void print_on(outputStream* os) const {
1869     os->print("[" PTR_FORMAT " - " PTR_FORMAT "] (" UINTX_FORMAT
1870       " bytes, %d %s pages), %s",
1871       addr, addr + size - 1, size, size / pagesize, describe_pagesize(pagesize),
1872       (type == VMEM_SHMATED ? "shmat" : "mmap")
1873     );
1874   }
1875 
1876   // Check that range is a sub range of memory block (or equal to memory block);
1877   // also check that range is fully page aligned to the page size if the block.
1878   void assert_is_valid_subrange(char* p, size_t s) const {
1879     if (!contains_range(p, s)) {
1880       trcVerbose("[" PTR_FORMAT " - " PTR_FORMAT "] is not a sub "
1881               "range of [" PTR_FORMAT " - " PTR_FORMAT "].",
1882               p, p + s, addr, addr + size);
1883       guarantee0(false);
1884     }
1885     if (!is_aligned_to(p, pagesize) || !is_aligned_to(p + s, pagesize)) {
1886       trcVerbose("range [" PTR_FORMAT " - " PTR_FORMAT "] is not"
1887               " aligned to pagesize (%lu)", p, p + s, (unsigned long) pagesize);
1888       guarantee0(false);
1889     }
1890   }
1891 };
1892 
1893 static struct {
1894   vmembk_t* first;
1895   MiscUtils::CritSect cs;
1896 } vmem;
1897 
1898 static void vmembk_add(char* addr, size_t size, size_t pagesize, int type) {
1899   vmembk_t* p = (vmembk_t*) ::malloc(sizeof(vmembk_t));
1900   assert0(p);
1901   if (p) {
1902     MiscUtils::AutoCritSect lck(&vmem.cs);
1903     p->addr = addr; p->size = size;
1904     p->pagesize = pagesize;
1905     p->type = type;
1906     p->next = vmem.first;
1907     vmem.first = p;
1908   }
1909 }
1910 
1911 static vmembk_t* vmembk_find(char* addr) {
1912   MiscUtils::AutoCritSect lck(&vmem.cs);
1913   for (vmembk_t* p = vmem.first; p; p = p->next) {
1914     if (p->addr <= addr && (p->addr + p->size) > addr) {
1915       return p;
1916     }
1917   }
1918   return NULL;
1919 }
1920 
1921 static void vmembk_remove(vmembk_t* p0) {
1922   MiscUtils::AutoCritSect lck(&vmem.cs);
1923   assert0(p0);
1924   assert0(vmem.first); // List should not be empty.
1925   for (vmembk_t** pp = &(vmem.first); *pp; pp = &((*pp)->next)) {
1926     if (*pp == p0) {
1927       *pp = p0->next;
1928       ::free(p0);
1929       return;
1930     }
1931   }
1932   assert0(false); // Not found?
1933 }
1934 
1935 static void vmembk_print_on(outputStream* os) {
1936   MiscUtils::AutoCritSect lck(&vmem.cs);
1937   for (vmembk_t* vmi = vmem.first; vmi; vmi = vmi->next) {
1938     vmi->print_on(os);
1939     os->cr();
1940   }
1941 }
1942 
1943 // Reserve and attach a section of System V memory.
1944 // If <requested_addr> is not NULL, function will attempt to attach the memory at the given
1945 // address. Failing that, it will attach the memory anywhere.
1946 // If <requested_addr> is NULL, function will attach the memory anywhere.
1947 //
1948 // <alignment_hint> is being ignored by this function. It is very probable however that the
1949 // alignment requirements are met anyway, because shmat() attaches at 256M boundaries.
1950 // Should this be not enogh, we can put more work into it.
1951 static char* reserve_shmated_memory (
1952   size_t bytes,
1953   char* requested_addr,
1954   size_t alignment_hint) {
1955 
1956   trcVerbose("reserve_shmated_memory " UINTX_FORMAT " bytes, wishaddress "
1957     PTR_FORMAT ", alignment_hint " UINTX_FORMAT "...",
1958     bytes, requested_addr, alignment_hint);
1959 
1960   // Either give me wish address or wish alignment but not both.
1961   assert0(!(requested_addr != NULL && alignment_hint != 0));
1962 
1963   // We must prevent anyone from attaching too close to the
1964   // BRK because that may cause malloc OOM.
1965   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
1966     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
1967       "Will attach anywhere.", requested_addr);
1968     // Act like the OS refused to attach there.
1969     requested_addr = NULL;
1970   }
1971 
1972   // For old AS/400's (V5R4 and older) we should not even be here - System V shared memory is not
1973   // really supported (max size 4GB), so reserve_mmapped_memory should have been used instead.
1974   if (os::Aix::on_pase_V5R4_or_older()) {
1975     ShouldNotReachHere();
1976   }
1977 
1978   // Align size of shm up to 64K to avoid errors if we later try to change the page size.
1979   const size_t size = align_up(bytes, 64*K);
1980 
1981   // Reserve the shared segment.
1982   int shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | S_IRUSR | S_IWUSR);
1983   if (shmid == -1) {
1984     trcVerbose("shmget(.., " UINTX_FORMAT ", ..) failed (errno: %d).", size, errno);
1985     return NULL;
1986   }
1987 
1988   // Important note:
1989   // It is very important that we, upon leaving this function, do not leave a shm segment alive.
1990   // We must right after attaching it remove it from the system. System V shm segments are global and
1991   // survive the process.
1992   // So, from here on: Do not assert, do not return, until we have called shmctl(IPC_RMID) (A).
1993 
1994   struct shmid_ds shmbuf;
1995   memset(&shmbuf, 0, sizeof(shmbuf));
1996   shmbuf.shm_pagesize = 64*K;
1997   if (shmctl(shmid, SHM_PAGESIZE, &shmbuf) != 0) {
1998     trcVerbose("Failed to set page size (need " UINTX_FORMAT " 64K pages) - shmctl failed with %d.",
1999                size / (64*K), errno);
2000     // I want to know if this ever happens.
2001     assert(false, "failed to set page size for shmat");
2002   }
2003 
2004   // Now attach the shared segment.
2005   // Note that I attach with SHM_RND - which means that the requested address is rounded down, if
2006   // needed, to the next lowest segment boundary. Otherwise the attach would fail if the address
2007   // were not a segment boundary.
2008   char* const addr = (char*) shmat(shmid, requested_addr, SHM_RND);
2009   const int errno_shmat = errno;
2010 
2011   // (A) Right after shmat and before handing shmat errors delete the shm segment.
2012   if (::shmctl(shmid, IPC_RMID, NULL) == -1) {
2013     trcVerbose("shmctl(%u, IPC_RMID) failed (%d)\n", shmid, errno);
2014     assert(false, "failed to remove shared memory segment!");
2015   }
2016 
2017   // Handle shmat error. If we failed to attach, just return.
2018   if (addr == (char*)-1) {
2019     trcVerbose("Failed to attach segment at " PTR_FORMAT " (%d).", requested_addr, errno_shmat);
2020     return NULL;
2021   }
2022 
2023   // Just for info: query the real page size. In case setting the page size did not
2024   // work (see above), the system may have given us something other then 4K (LDR_CNTRL).
2025   const size_t real_pagesize = os::Aix::query_pagesize(addr);
2026   if (real_pagesize != shmbuf.shm_pagesize) {
2027     trcVerbose("pagesize is, surprisingly, %h.", real_pagesize);
2028   }
2029 
2030   if (addr) {
2031     trcVerbose("shm-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes, " UINTX_FORMAT " %s pages)",
2032       addr, addr + size - 1, size, size/real_pagesize, describe_pagesize(real_pagesize));
2033   } else {
2034     if (requested_addr != NULL) {
2035       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at with address " PTR_FORMAT ".", size, requested_addr);
2036     } else {
2037       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at any address.", size);
2038     }
2039   }
2040 
2041   // book-keeping
2042   vmembk_add(addr, size, real_pagesize, VMEM_SHMATED);
2043   assert0(is_aligned_to(addr, os::vm_page_size()));
2044 
2045   return addr;
2046 }
2047 
2048 static bool release_shmated_memory(char* addr, size_t size) {
2049 
2050   trcVerbose("release_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2051     addr, addr + size - 1);
2052 
2053   bool rc = false;
2054 
2055   // TODO: is there a way to verify shm size without doing bookkeeping?
2056   if (::shmdt(addr) != 0) {
2057     trcVerbose("error (%d).", errno);
2058   } else {
2059     trcVerbose("ok.");
2060     rc = true;
2061   }
2062   return rc;
2063 }
2064 
2065 static bool uncommit_shmated_memory(char* addr, size_t size) {
2066   trcVerbose("uncommit_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2067     addr, addr + size - 1);
2068 
2069   const bool rc = my_disclaim64(addr, size);
2070 
2071   if (!rc) {
2072     trcVerbose("my_disclaim64(" PTR_FORMAT ", " UINTX_FORMAT ") failed.\n", addr, size);
2073     return false;
2074   }
2075   return true;
2076 }
2077 
2078 ////////////////////////////////  mmap-based routines /////////////////////////////////
2079 
2080 // Reserve memory via mmap.
2081 // If <requested_addr> is given, an attempt is made to attach at the given address.
2082 // Failing that, memory is allocated at any address.
2083 // If <alignment_hint> is given and <requested_addr> is NULL, an attempt is made to
2084 // allocate at an address aligned with the given alignment. Failing that, memory
2085 // is aligned anywhere.
2086 static char* reserve_mmaped_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2087   trcVerbose("reserve_mmaped_memory " UINTX_FORMAT " bytes, wishaddress " PTR_FORMAT ", "
2088     "alignment_hint " UINTX_FORMAT "...",
2089     bytes, requested_addr, alignment_hint);
2090 
2091   // If a wish address is given, but not aligned to 4K page boundary, mmap will fail.
2092   if (requested_addr && !is_aligned_to(requested_addr, os::vm_page_size()) != 0) {
2093     trcVerbose("Wish address " PTR_FORMAT " not aligned to page boundary.", requested_addr);
2094     return NULL;
2095   }
2096 
2097   // We must prevent anyone from attaching too close to the
2098   // BRK because that may cause malloc OOM.
2099   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
2100     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
2101       "Will attach anywhere.", requested_addr);
2102     // Act like the OS refused to attach there.
2103     requested_addr = NULL;
2104   }
2105 
2106   // Specify one or the other but not both.
2107   assert0(!(requested_addr != NULL && alignment_hint > 0));
2108 
2109   // In 64K mode, we claim the global page size (os::vm_page_size())
2110   // is 64K. This is one of the few points where that illusion may
2111   // break, because mmap() will always return memory aligned to 4K. So
2112   // we must ensure we only ever return memory aligned to 64k.
2113   if (alignment_hint) {
2114     alignment_hint = lcm(alignment_hint, os::vm_page_size());
2115   } else {
2116     alignment_hint = os::vm_page_size();
2117   }
2118 
2119   // Size shall always be a multiple of os::vm_page_size (esp. in 64K mode).
2120   const size_t size = align_up(bytes, os::vm_page_size());
2121 
2122   // alignment: Allocate memory large enough to include an aligned range of the right size and
2123   // cut off the leading and trailing waste pages.
2124   assert0(alignment_hint != 0 && is_aligned_to(alignment_hint, os::vm_page_size())); // see above
2125   const size_t extra_size = size + alignment_hint;
2126 
2127   // Note: MAP_SHARED (instead of MAP_PRIVATE) needed to be able to
2128   // later use msync(MS_INVALIDATE) (see os::uncommit_memory).
2129   int flags = MAP_ANONYMOUS | MAP_SHARED;
2130 
2131   // MAP_FIXED is needed to enforce requested_addr - manpage is vague about what
2132   // it means if wishaddress is given but MAP_FIXED is not set.
2133   //
2134   // Important! Behaviour differs depending on whether SPEC1170 mode is active or not.
2135   // SPEC1170 mode active: behaviour like POSIX, MAP_FIXED will clobber existing mappings.
2136   // SPEC1170 mode not active: behaviour, unlike POSIX, is that no existing mappings will
2137   // get clobbered.
2138   if (requested_addr != NULL) {
2139     if (!os::Aix::xpg_sus_mode()) {  // not SPEC1170 Behaviour
2140       flags |= MAP_FIXED;
2141     }
2142   }
2143 
2144   char* addr = (char*)::mmap(requested_addr, extra_size,
2145       PROT_READ|PROT_WRITE|PROT_EXEC, flags, -1, 0);
2146 
2147   if (addr == MAP_FAILED) {
2148     trcVerbose("mmap(" PTR_FORMAT ", " UINTX_FORMAT ", ..) failed (%d)", requested_addr, size, errno);
2149     return NULL;
2150   }
2151 
2152   // Handle alignment.
2153   char* const addr_aligned = align_up(addr, alignment_hint);
2154   const size_t waste_pre = addr_aligned - addr;
2155   char* const addr_aligned_end = addr_aligned + size;
2156   const size_t waste_post = extra_size - waste_pre - size;
2157   if (waste_pre > 0) {
2158     ::munmap(addr, waste_pre);
2159   }
2160   if (waste_post > 0) {
2161     ::munmap(addr_aligned_end, waste_post);
2162   }
2163   addr = addr_aligned;
2164 
2165   if (addr) {
2166     trcVerbose("mmap-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes)",
2167       addr, addr + bytes, bytes);
2168   } else {
2169     if (requested_addr != NULL) {
2170       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at wish address " PTR_FORMAT ".", bytes, requested_addr);
2171     } else {
2172       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at any address.", bytes);
2173     }
2174   }
2175 
2176   // bookkeeping
2177   vmembk_add(addr, size, 4*K, VMEM_MAPPED);
2178 
2179   // Test alignment, see above.
2180   assert0(is_aligned_to(addr, os::vm_page_size()));
2181 
2182   return addr;
2183 }
2184 
2185 static bool release_mmaped_memory(char* addr, size_t size) {
2186   assert0(is_aligned_to(addr, os::vm_page_size()));
2187   assert0(is_aligned_to(size, os::vm_page_size()));
2188 
2189   trcVerbose("release_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2190     addr, addr + size - 1);
2191   bool rc = false;
2192 
2193   if (::munmap(addr, size) != 0) {
2194     trcVerbose("failed (%d)\n", errno);
2195     rc = false;
2196   } else {
2197     trcVerbose("ok.");
2198     rc = true;
2199   }
2200 
2201   return rc;
2202 }
2203 
2204 static bool uncommit_mmaped_memory(char* addr, size_t size) {
2205 
2206   assert0(is_aligned_to(addr, os::vm_page_size()));
2207   assert0(is_aligned_to(size, os::vm_page_size()));
2208 
2209   trcVerbose("uncommit_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2210     addr, addr + size - 1);
2211   bool rc = false;
2212 
2213   // Uncommit mmap memory with msync MS_INVALIDATE.
2214   if (::msync(addr, size, MS_INVALIDATE) != 0) {
2215     trcVerbose("failed (%d)\n", errno);
2216     rc = false;
2217   } else {
2218     trcVerbose("ok.");
2219     rc = true;
2220   }
2221 
2222   return rc;
2223 }
2224 
2225 int os::vm_page_size() {
2226   // Seems redundant as all get out.
2227   assert(os::Aix::page_size() != -1, "must call os::init");
2228   return os::Aix::page_size();
2229 }
2230 
2231 // Aix allocates memory by pages.
2232 int os::vm_allocation_granularity() {
2233   assert(os::Aix::page_size() != -1, "must call os::init");
2234   return os::Aix::page_size();
2235 }
2236 
2237 #ifdef PRODUCT
2238 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2239                                     int err) {
2240   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2241           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2242           os::errno_name(err), err);
2243 }
2244 #endif
2245 
2246 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2247                                   const char* mesg) {
2248   assert(mesg != NULL, "mesg must be specified");
2249   if (!pd_commit_memory(addr, size, exec)) {
2250     // Add extra info in product mode for vm_exit_out_of_memory():
2251     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2252     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2253   }
2254 }
2255 
2256 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2257 
2258   assert(is_aligned_to(addr, os::vm_page_size()),
2259     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2260     p2i(addr), os::vm_page_size());
2261   assert(is_aligned_to(size, os::vm_page_size()),
2262     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2263     size, os::vm_page_size());
2264 
2265   vmembk_t* const vmi = vmembk_find(addr);
2266   guarantee0(vmi);
2267   vmi->assert_is_valid_subrange(addr, size);
2268 
2269   trcVerbose("commit_memory [" PTR_FORMAT " - " PTR_FORMAT "].", addr, addr + size - 1);
2270 
2271   if (UseExplicitCommit) {
2272     // AIX commits memory on touch. So, touch all pages to be committed.
2273     for (char* p = addr; p < (addr + size); p += 4*K) {
2274       *p = '\0';
2275     }
2276   }
2277 
2278   return true;
2279 }
2280 
2281 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, bool exec) {
2282   return pd_commit_memory(addr, size, exec);
2283 }
2284 
2285 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2286                                   size_t alignment_hint, bool exec,
2287                                   const char* mesg) {
2288   // Alignment_hint is ignored on this OS.
2289   pd_commit_memory_or_exit(addr, size, exec, mesg);
2290 }
2291 
2292 bool os::pd_uncommit_memory(char* addr, size_t size) {
2293   assert(is_aligned_to(addr, os::vm_page_size()),
2294     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2295     p2i(addr), os::vm_page_size());
2296   assert(is_aligned_to(size, os::vm_page_size()),
2297     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2298     size, os::vm_page_size());
2299 
2300   // Dynamically do different things for mmap/shmat.
2301   const vmembk_t* const vmi = vmembk_find(addr);
2302   guarantee0(vmi);
2303   vmi->assert_is_valid_subrange(addr, size);
2304 
2305   if (vmi->type == VMEM_SHMATED) {
2306     return uncommit_shmated_memory(addr, size);
2307   } else {
2308     return uncommit_mmaped_memory(addr, size);
2309   }
2310 }
2311 
2312 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2313   // Do not call this; no need to commit stack pages on AIX.
2314   ShouldNotReachHere();
2315   return true;
2316 }
2317 
2318 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2319   // Do not call this; no need to commit stack pages on AIX.
2320   ShouldNotReachHere();
2321   return true;
2322 }
2323 
2324 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2325 }
2326 
2327 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2328 }
2329 
2330 void os::numa_make_global(char *addr, size_t bytes) {
2331 }
2332 
2333 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2334 }
2335 
2336 bool os::numa_topology_changed() {
2337   return false;
2338 }
2339 
2340 size_t os::numa_get_groups_num() {
2341   return 1;
2342 }
2343 
2344 int os::numa_get_group_id() {
2345   return 0;
2346 }
2347 
2348 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2349   if (size > 0) {
2350     ids[0] = 0;
2351     return 1;
2352   }
2353   return 0;
2354 }
2355 
2356 bool os::get_page_info(char *start, page_info* info) {
2357   return false;
2358 }
2359 
2360 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2361   return end;
2362 }
2363 
2364 // Reserves and attaches a shared memory segment.
2365 // Will assert if a wish address is given and could not be obtained.
2366 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2367 
2368   // All other Unices do a mmap(MAP_FIXED) if the addr is given,
2369   // thereby clobbering old mappings at that place. That is probably
2370   // not intended, never used and almost certainly an error were it
2371   // ever be used this way (to try attaching at a specified address
2372   // without clobbering old mappings an alternate API exists,
2373   // os::attempt_reserve_memory_at()).
2374   // Instead of mimicking the dangerous coding of the other platforms, here I
2375   // just ignore the request address (release) or assert(debug).
2376   assert0(requested_addr == NULL);
2377 
2378   // Always round to os::vm_page_size(), which may be larger than 4K.
2379   bytes = align_up(bytes, os::vm_page_size());
2380   const size_t alignment_hint0 =
2381     alignment_hint ? align_up(alignment_hint, os::vm_page_size()) : 0;
2382 
2383   // In 4K mode always use mmap.
2384   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2385   if (os::vm_page_size() == 4*K) {
2386     return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2387   } else {
2388     if (bytes >= Use64KPagesThreshold) {
2389       return reserve_shmated_memory(bytes, requested_addr, alignment_hint);
2390     } else {
2391       return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2392     }
2393   }
2394 }
2395 
2396 bool os::pd_release_memory(char* addr, size_t size) {
2397 
2398   // Dynamically do different things for mmap/shmat.
2399   vmembk_t* const vmi = vmembk_find(addr);
2400   guarantee0(vmi);
2401 
2402   // Always round to os::vm_page_size(), which may be larger than 4K.
2403   size = align_up(size, os::vm_page_size());
2404   addr = align_up(addr, os::vm_page_size());
2405 
2406   bool rc = false;
2407   bool remove_bookkeeping = false;
2408   if (vmi->type == VMEM_SHMATED) {
2409     // For shmatted memory, we do:
2410     // - If user wants to release the whole range, release the memory (shmdt).
2411     // - If user only wants to release a partial range, uncommit (disclaim) that
2412     //   range. That way, at least, we do not use memory anymore (bust still page
2413     //   table space).
2414     vmi->assert_is_valid_subrange(addr, size);
2415     if (addr == vmi->addr && size == vmi->size) {
2416       rc = release_shmated_memory(addr, size);
2417       remove_bookkeeping = true;
2418     } else {
2419       rc = uncommit_shmated_memory(addr, size);
2420     }
2421   } else {
2422     // User may unmap partial regions but region has to be fully contained.
2423 #ifdef ASSERT
2424     vmi->assert_is_valid_subrange(addr, size);
2425 #endif
2426     rc = release_mmaped_memory(addr, size);
2427     remove_bookkeeping = true;
2428   }
2429 
2430   // update bookkeeping
2431   if (rc && remove_bookkeeping) {
2432     vmembk_remove(vmi);
2433   }
2434 
2435   return rc;
2436 }
2437 
2438 static bool checked_mprotect(char* addr, size_t size, int prot) {
2439 
2440   // Little problem here: if SPEC1170 behaviour is off, mprotect() on AIX will
2441   // not tell me if protection failed when trying to protect an un-protectable range.
2442   //
2443   // This means if the memory was allocated using shmget/shmat, protection wont work
2444   // but mprotect will still return 0:
2445   //
2446   // See http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/mprotect.htm
2447 
2448   bool rc = ::mprotect(addr, size, prot) == 0 ? true : false;
2449 
2450   if (!rc) {
2451     const char* const s_errno = os::errno_name(errno);
2452     warning("mprotect(" PTR_FORMAT "-" PTR_FORMAT ", 0x%X) failed (%s).", addr, addr + size, prot, s_errno);
2453     return false;
2454   }
2455 
2456   // mprotect success check
2457   //
2458   // Mprotect said it changed the protection but can I believe it?
2459   //
2460   // To be sure I need to check the protection afterwards. Try to
2461   // read from protected memory and check whether that causes a segfault.
2462   //
2463   if (!os::Aix::xpg_sus_mode()) {
2464 
2465     if (CanUseSafeFetch32()) {
2466 
2467       const bool read_protected =
2468         (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2469          SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2470 
2471       if (prot & PROT_READ) {
2472         rc = !read_protected;
2473       } else {
2474         rc = read_protected;
2475       }
2476 
2477       if (!rc) {
2478         if (os::Aix::on_pase()) {
2479           // There is an issue on older PASE systems where mprotect() will return success but the
2480           // memory will not be protected.
2481           // This has nothing to do with the problem of using mproect() on SPEC1170 incompatible
2482           // machines; we only see it rarely, when using mprotect() to protect the guard page of
2483           // a stack. It is an OS error.
2484           //
2485           // A valid strategy is just to try again. This usually works. :-/
2486 
2487           ::usleep(1000);
2488           if (::mprotect(addr, size, prot) == 0) {
2489             const bool read_protected_2 =
2490               (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2491               SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2492             rc = true;
2493           }
2494         }
2495       }
2496     }
2497   }
2498 
2499   assert(rc == true, "mprotect failed.");
2500 
2501   return rc;
2502 }
2503 
2504 // Set protections specified
2505 bool os::protect_memory(char* addr, size_t size, ProtType prot, bool is_committed) {
2506   unsigned int p = 0;
2507   switch (prot) {
2508   case MEM_PROT_NONE: p = PROT_NONE; break;
2509   case MEM_PROT_READ: p = PROT_READ; break;
2510   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2511   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2512   default:
2513     ShouldNotReachHere();
2514   }
2515   // is_committed is unused.
2516   return checked_mprotect(addr, size, p);
2517 }
2518 
2519 bool os::guard_memory(char* addr, size_t size) {
2520   return checked_mprotect(addr, size, PROT_NONE);
2521 }
2522 
2523 bool os::unguard_memory(char* addr, size_t size) {
2524   return checked_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
2525 }
2526 
2527 // Large page support
2528 
2529 static size_t _large_page_size = 0;
2530 
2531 // Enable large page support if OS allows that.
2532 void os::large_page_init() {
2533   return; // Nothing to do. See query_multipage_support and friends.
2534 }
2535 
2536 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2537   // reserve_memory_special() is used to allocate large paged memory. On AIX, we implement
2538   // 64k paged memory reservation using the normal memory allocation paths (os::reserve_memory()),
2539   // so this is not needed.
2540   assert(false, "should not be called on AIX");
2541   return NULL;
2542 }
2543 
2544 bool os::release_memory_special(char* base, size_t bytes) {
2545   // Detaching the SHM segment will also delete it, see reserve_memory_special().
2546   Unimplemented();
2547   return false;
2548 }
2549 
2550 size_t os::large_page_size() {
2551   return _large_page_size;
2552 }
2553 
2554 bool os::can_commit_large_page_memory() {
2555   // Does not matter, we do not support huge pages.
2556   return false;
2557 }
2558 
2559 bool os::can_execute_large_page_memory() {
2560   // Does not matter, we do not support huge pages.
2561   return false;
2562 }
2563 
2564 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
2565   assert(file_desc >= 0, "file_desc is not valid");
2566   char* result = NULL;
2567 
2568   // Always round to os::vm_page_size(), which may be larger than 4K.
2569   bytes = align_up(bytes, os::vm_page_size());
2570   result = reserve_mmaped_memory(bytes, requested_addr, 0);
2571 
2572   if (result != NULL) {
2573     if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
2574       vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
2575     }
2576   }
2577   return result;
2578 }
2579 
2580 // Reserve memory at an arbitrary address, only if that area is
2581 // available (and not reserved for something else).
2582 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2583   char* addr = NULL;
2584 
2585   // Always round to os::vm_page_size(), which may be larger than 4K.
2586   bytes = align_up(bytes, os::vm_page_size());
2587 
2588   // In 4K mode always use mmap.
2589   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2590   if (os::vm_page_size() == 4*K) {
2591     return reserve_mmaped_memory(bytes, requested_addr, 0);
2592   } else {
2593     if (bytes >= Use64KPagesThreshold) {
2594       return reserve_shmated_memory(bytes, requested_addr, 0);
2595     } else {
2596       return reserve_mmaped_memory(bytes, requested_addr, 0);
2597     }
2598   }
2599 
2600   return addr;
2601 }
2602 
2603 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2604   return ::read(fd, buf, nBytes);
2605 }
2606 
2607 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
2608   return ::pread(fd, buf, nBytes, offset);
2609 }
2610 
2611 void os::naked_short_sleep(jlong ms) {
2612   struct timespec req;
2613 
2614   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2615   req.tv_sec = 0;
2616   if (ms > 0) {
2617     req.tv_nsec = (ms % 1000) * 1000000;
2618   }
2619   else {
2620     req.tv_nsec = 1;
2621   }
2622 
2623   nanosleep(&req, NULL);
2624 
2625   return;
2626 }
2627 
2628 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2629 void os::infinite_sleep() {
2630   while (true) {    // sleep forever ...
2631     ::sleep(100);   // ... 100 seconds at a time
2632   }
2633 }
2634 
2635 // Used to convert frequent JVM_Yield() to nops
2636 bool os::dont_yield() {
2637   return DontYieldALot;
2638 }
2639 
2640 void os::naked_yield() {
2641   sched_yield();
2642 }
2643 
2644 ////////////////////////////////////////////////////////////////////////////////
2645 // thread priority support
2646 
2647 // From AIX manpage to pthread_setschedparam
2648 // (see: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?
2649 //    topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_setschedparam.htm):
2650 //
2651 // "If schedpolicy is SCHED_OTHER, then sched_priority must be in the
2652 // range from 40 to 80, where 40 is the least favored priority and 80
2653 // is the most favored."
2654 //
2655 // (Actually, I doubt this even has an impact on AIX, as we do kernel
2656 // scheduling there; however, this still leaves iSeries.)
2657 //
2658 // We use the same values for AIX and PASE.
2659 int os::java_to_os_priority[CriticalPriority + 1] = {
2660   54,             // 0 Entry should never be used
2661 
2662   55,             // 1 MinPriority
2663   55,             // 2
2664   56,             // 3
2665 
2666   56,             // 4
2667   57,             // 5 NormPriority
2668   57,             // 6
2669 
2670   58,             // 7
2671   58,             // 8
2672   59,             // 9 NearMaxPriority
2673 
2674   60,             // 10 MaxPriority
2675 
2676   60              // 11 CriticalPriority
2677 };
2678 
2679 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2680   if (!UseThreadPriorities) return OS_OK;
2681   pthread_t thr = thread->osthread()->pthread_id();
2682   int policy = SCHED_OTHER;
2683   struct sched_param param;
2684   param.sched_priority = newpri;
2685   int ret = pthread_setschedparam(thr, policy, &param);
2686 
2687   if (ret != 0) {
2688     trcVerbose("Could not change priority for thread %d to %d (error %d, %s)",
2689         (int)thr, newpri, ret, os::errno_name(ret));
2690   }
2691   return (ret == 0) ? OS_OK : OS_ERR;
2692 }
2693 
2694 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2695   if (!UseThreadPriorities) {
2696     *priority_ptr = java_to_os_priority[NormPriority];
2697     return OS_OK;
2698   }
2699   pthread_t thr = thread->osthread()->pthread_id();
2700   int policy = SCHED_OTHER;
2701   struct sched_param param;
2702   int ret = pthread_getschedparam(thr, &policy, &param);
2703   *priority_ptr = param.sched_priority;
2704 
2705   return (ret == 0) ? OS_OK : OS_ERR;
2706 }
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 static 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   // Initialize data for jdk.internal.misc.Signal
3572   if (!ReduceSignalUsage) {
3573     jdk_misc_signal_init();
3574   }
3575 
3576   // Check and sets minimum stack sizes against command line options
3577   if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
3578     return JNI_ERR;
3579   }
3580 
3581   if (UseNUMA) {
3582     UseNUMA = false;
3583     warning("NUMA optimizations are not available on this OS.");
3584   }
3585 
3586   if (MaxFDLimit) {
3587     // Set the number of file descriptors to max. print out error
3588     // if getrlimit/setrlimit fails but continue regardless.
3589     struct rlimit nbr_files;
3590     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3591     if (status != 0) {
3592       log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
3593     } else {
3594       nbr_files.rlim_cur = nbr_files.rlim_max;
3595       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3596       if (status != 0) {
3597         log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
3598       }
3599     }
3600   }
3601 
3602   if (PerfAllowAtExitRegistration) {
3603     // Only register atexit functions if PerfAllowAtExitRegistration is set.
3604     // At exit functions can be delayed until process exit time, which
3605     // can be problematic for embedded VM situations. Embedded VMs should
3606     // call DestroyJavaVM() to assure that VM resources are released.
3607 
3608     // Note: perfMemory_exit_helper atexit function may be removed in
3609     // the future if the appropriate cleanup code can be added to the
3610     // VM_Exit VMOperation's doit method.
3611     if (atexit(perfMemory_exit_helper) != 0) {
3612       warning("os::init_2 atexit(perfMemory_exit_helper) failed");
3613     }
3614   }
3615 
3616   return JNI_OK;
3617 }
3618 
3619 // Mark the polling page as unreadable
3620 void os::make_polling_page_unreadable(void) {
3621   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
3622     fatal("Could not disable polling page");
3623   }
3624 };
3625 
3626 // Mark the polling page as readable
3627 void os::make_polling_page_readable(void) {
3628   // Changed according to os_linux.cpp.
3629   if (!checked_mprotect((char *)_polling_page, Aix::page_size(), PROT_READ)) {
3630     fatal("Could not enable polling page at " PTR_FORMAT, _polling_page);
3631   }
3632 };
3633 
3634 int os::active_processor_count() {
3635   // User has overridden the number of active processors
3636   if (ActiveProcessorCount > 0) {
3637     log_trace(os)("active_processor_count: "
3638                   "active processor count set by user : %d",
3639                   ActiveProcessorCount);
3640     return ActiveProcessorCount;
3641   }
3642 
3643   int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3644   assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3645   return online_cpus;
3646 }
3647 
3648 void os::set_native_thread_name(const char *name) {
3649   // Not yet implemented.
3650   return;
3651 }
3652 
3653 bool os::distribute_processes(uint length, uint* distribution) {
3654   // Not yet implemented.
3655   return false;
3656 }
3657 
3658 bool os::bind_to_processor(uint processor_id) {
3659   // Not yet implemented.
3660   return false;
3661 }
3662 
3663 void os::SuspendedThreadTask::internal_do_task() {
3664   if (do_suspend(_thread->osthread())) {
3665     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3666     do_task(context);
3667     do_resume(_thread->osthread());
3668   }
3669 }
3670 
3671 ////////////////////////////////////////////////////////////////////////////////
3672 // debug support
3673 
3674 bool os::find(address addr, outputStream* st) {
3675 
3676   st->print(PTR_FORMAT ": ", addr);
3677 
3678   loaded_module_t lm;
3679   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL ||
3680       LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
3681     st->print_cr("%s", lm.path);
3682     return true;
3683   }
3684 
3685   return false;
3686 }
3687 
3688 ////////////////////////////////////////////////////////////////////////////////
3689 // misc
3690 
3691 // This does not do anything on Aix. This is basically a hook for being
3692 // able to use structured exception handling (thread-local exception filters)
3693 // on, e.g., Win32.
3694 void
3695 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
3696                          JavaCallArguments* args, Thread* thread) {
3697   f(value, method, args, thread);
3698 }
3699 
3700 void os::print_statistics() {
3701 }
3702 
3703 bool os::message_box(const char* title, const char* message) {
3704   int i;
3705   fdStream err(defaultStream::error_fd());
3706   for (i = 0; i < 78; i++) err.print_raw("=");
3707   err.cr();
3708   err.print_raw_cr(title);
3709   for (i = 0; i < 78; i++) err.print_raw("-");
3710   err.cr();
3711   err.print_raw_cr(message);
3712   for (i = 0; i < 78; i++) err.print_raw("=");
3713   err.cr();
3714 
3715   char buf[16];
3716   // Prevent process from exiting upon "read error" without consuming all CPU
3717   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3718 
3719   return buf[0] == 'y' || buf[0] == 'Y';
3720 }
3721 
3722 // Is a (classpath) directory empty?
3723 bool os::dir_is_empty(const char* path) {
3724   DIR *dir = NULL;
3725   struct dirent *ptr;
3726 
3727   dir = opendir(path);
3728   if (dir == NULL) return true;
3729 
3730   /* Scan the directory */
3731   bool result = true;
3732   while (result && (ptr = readdir(dir)) != NULL) {
3733     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3734       result = false;
3735     }
3736   }
3737   closedir(dir);
3738   return result;
3739 }
3740 
3741 // This code originates from JDK's sysOpen and open64_w
3742 // from src/solaris/hpi/src/system_md.c
3743 
3744 int os::open(const char *path, int oflag, int mode) {
3745 
3746   if (strlen(path) > MAX_PATH - 1) {
3747     errno = ENAMETOOLONG;
3748     return -1;
3749   }
3750   int fd;
3751 
3752   fd = ::open64(path, oflag, mode);
3753   if (fd == -1) return -1;
3754 
3755   // If the open succeeded, the file might still be a directory.
3756   {
3757     struct stat64 buf64;
3758     int ret = ::fstat64(fd, &buf64);
3759     int st_mode = buf64.st_mode;
3760 
3761     if (ret != -1) {
3762       if ((st_mode & S_IFMT) == S_IFDIR) {
3763         errno = EISDIR;
3764         ::close(fd);
3765         return -1;
3766       }
3767     } else {
3768       ::close(fd);
3769       return -1;
3770     }
3771   }
3772 
3773   // All file descriptors that are opened in the JVM and not
3774   // specifically destined for a subprocess should have the
3775   // close-on-exec flag set. If we don't set it, then careless 3rd
3776   // party native code might fork and exec without closing all
3777   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3778   // UNIXProcess.c), and this in turn might:
3779   //
3780   // - cause end-of-file to fail to be detected on some file
3781   //   descriptors, resulting in mysterious hangs, or
3782   //
3783   // - might cause an fopen in the subprocess to fail on a system
3784   //   suffering from bug 1085341.
3785   //
3786   // (Yes, the default setting of the close-on-exec flag is a Unix
3787   // design flaw.)
3788   //
3789   // See:
3790   // 1085341: 32-bit stdio routines should support file descriptors >255
3791   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3792   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3793 #ifdef FD_CLOEXEC
3794   {
3795     int flags = ::fcntl(fd, F_GETFD);
3796     if (flags != -1)
3797       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3798   }
3799 #endif
3800 
3801   return fd;
3802 }
3803 
3804 // create binary file, rewriting existing file if required
3805 int os::create_binary_file(const char* path, bool rewrite_existing) {
3806   int oflags = O_WRONLY | O_CREAT;
3807   if (!rewrite_existing) {
3808     oflags |= O_EXCL;
3809   }
3810   return ::open64(path, oflags, S_IREAD | S_IWRITE);
3811 }
3812 
3813 // return current position of file pointer
3814 jlong os::current_file_offset(int fd) {
3815   return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
3816 }
3817 
3818 // move file pointer to the specified offset
3819 jlong os::seek_to_file_offset(int fd, jlong offset) {
3820   return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
3821 }
3822 
3823 // This code originates from JDK's sysAvailable
3824 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3825 
3826 int os::available(int fd, jlong *bytes) {
3827   jlong cur, end;
3828   int mode;
3829   struct stat64 buf64;
3830 
3831   if (::fstat64(fd, &buf64) >= 0) {
3832     mode = buf64.st_mode;
3833     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3834       int n;
3835       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3836         *bytes = n;
3837         return 1;
3838       }
3839     }
3840   }
3841   if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
3842     return 0;
3843   } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
3844     return 0;
3845   } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
3846     return 0;
3847   }
3848   *bytes = end - cur;
3849   return 1;
3850 }
3851 
3852 // Map a block of memory.
3853 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3854                         char *addr, size_t bytes, bool read_only,
3855                         bool allow_exec) {
3856   int prot;
3857   int flags = MAP_PRIVATE;
3858 
3859   if (read_only) {
3860     prot = PROT_READ;
3861     flags = MAP_SHARED;
3862   } else {
3863     prot = PROT_READ | PROT_WRITE;
3864     flags = MAP_PRIVATE;
3865   }
3866 
3867   if (allow_exec) {
3868     prot |= PROT_EXEC;
3869   }
3870 
3871   if (addr != NULL) {
3872     flags |= MAP_FIXED;
3873   }
3874 
3875   // Allow anonymous mappings if 'fd' is -1.
3876   if (fd == -1) {
3877     flags |= MAP_ANONYMOUS;
3878   }
3879 
3880   char* mapped_address = (char*)::mmap(addr, (size_t)bytes, prot, flags,
3881                                      fd, file_offset);
3882   if (mapped_address == MAP_FAILED) {
3883     return NULL;
3884   }
3885   return mapped_address;
3886 }
3887 
3888 // Remap a block of memory.
3889 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3890                           char *addr, size_t bytes, bool read_only,
3891                           bool allow_exec) {
3892   // same as map_memory() on this OS
3893   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3894                         allow_exec);
3895 }
3896 
3897 // Unmap a block of memory.
3898 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3899   return munmap(addr, bytes) == 0;
3900 }
3901 
3902 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3903 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3904 // of a thread.
3905 //
3906 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3907 // the fast estimate available on the platform.
3908 
3909 jlong os::current_thread_cpu_time() {
3910   // return user + sys since the cost is the same
3911   const jlong n = os::thread_cpu_time(Thread::current(), true /* user + sys */);
3912   assert(n >= 0, "negative CPU time");
3913   return n;
3914 }
3915 
3916 jlong os::thread_cpu_time(Thread* thread) {
3917   // consistent with what current_thread_cpu_time() returns
3918   const jlong n = os::thread_cpu_time(thread, true /* user + sys */);
3919   assert(n >= 0, "negative CPU time");
3920   return n;
3921 }
3922 
3923 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
3924   const jlong n = os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
3925   assert(n >= 0, "negative CPU time");
3926   return n;
3927 }
3928 
3929 static bool thread_cpu_time_unchecked(Thread* thread, jlong* p_sys_time, jlong* p_user_time) {
3930   bool error = false;
3931 
3932   jlong sys_time = 0;
3933   jlong user_time = 0;
3934 
3935   // Reimplemented using getthrds64().
3936   //
3937   // Works like this:
3938   // For the thread in question, get the kernel thread id. Then get the
3939   // kernel thread statistics using that id.
3940   //
3941   // This only works of course when no pthread scheduling is used,
3942   // i.e. there is a 1:1 relationship to kernel threads.
3943   // On AIX, see AIXTHREAD_SCOPE variable.
3944 
3945   pthread_t pthtid = thread->osthread()->pthread_id();
3946 
3947   // retrieve kernel thread id for the pthread:
3948   tid64_t tid = 0;
3949   struct __pthrdsinfo pinfo;
3950   // I just love those otherworldly IBM APIs which force me to hand down
3951   // dummy buffers for stuff I dont care for...
3952   char dummy[1];
3953   int dummy_size = sizeof(dummy);
3954   if (pthread_getthrds_np(&pthtid, PTHRDSINFO_QUERY_TID, &pinfo, sizeof(pinfo),
3955                           dummy, &dummy_size) == 0) {
3956     tid = pinfo.__pi_tid;
3957   } else {
3958     tty->print_cr("pthread_getthrds_np failed.");
3959     error = true;
3960   }
3961 
3962   // retrieve kernel timing info for that kernel thread
3963   if (!error) {
3964     struct thrdentry64 thrdentry;
3965     if (getthrds64(getpid(), &thrdentry, sizeof(thrdentry), &tid, 1) == 1) {
3966       sys_time = thrdentry.ti_ru.ru_stime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_stime.tv_usec * 1000LL;
3967       user_time = thrdentry.ti_ru.ru_utime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_utime.tv_usec * 1000LL;
3968     } else {
3969       tty->print_cr("pthread_getthrds_np failed.");
3970       error = true;
3971     }
3972   }
3973 
3974   if (p_sys_time) {
3975     *p_sys_time = sys_time;
3976   }
3977 
3978   if (p_user_time) {
3979     *p_user_time = user_time;
3980   }
3981 
3982   if (error) {
3983     return false;
3984   }
3985 
3986   return true;
3987 }
3988 
3989 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
3990   jlong sys_time;
3991   jlong user_time;
3992 
3993   if (!thread_cpu_time_unchecked(thread, &sys_time, &user_time)) {
3994     return -1;
3995   }
3996 
3997   return user_sys_cpu_time ? sys_time + user_time : user_time;
3998 }
3999 
4000 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4001   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4002   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4003   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4004   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4005 }
4006 
4007 void os::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 bool os::is_thread_cpu_time_supported() {
4015   return true;
4016 }
4017 
4018 // System loadavg support. Returns -1 if load average cannot be obtained.
4019 // For now just return the system wide load average (no processor sets).
4020 int os::loadavg(double values[], int nelem) {
4021 
4022   guarantee(nelem >= 0 && nelem <= 3, "argument error");
4023   guarantee(values, "argument error");
4024 
4025   if (os::Aix::on_pase()) {
4026 
4027     // AS/400 PASE: use libo4 porting library
4028     double v[3] = { 0.0, 0.0, 0.0 };
4029 
4030     if (libo4::get_load_avg(v, v + 1, v + 2)) {
4031       for (int i = 0; i < nelem; i ++) {
4032         values[i] = v[i];
4033       }
4034       return nelem;
4035     } else {
4036       return -1;
4037     }
4038 
4039   } else {
4040 
4041     // AIX: use libperfstat
4042     libperfstat::cpuinfo_t ci;
4043     if (libperfstat::get_cpuinfo(&ci)) {
4044       for (int i = 0; i < nelem; i++) {
4045         values[i] = ci.loadavg[i];
4046       }
4047     } else {
4048       return -1;
4049     }
4050     return nelem;
4051   }
4052 }
4053 
4054 void os::pause() {
4055   char filename[MAX_PATH];
4056   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4057     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4058   } else {
4059     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4060   }
4061 
4062   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4063   if (fd != -1) {
4064     struct stat buf;
4065     ::close(fd);
4066     while (::stat(filename, &buf) == 0) {
4067       (void)::poll(NULL, 0, 100);
4068     }
4069   } else {
4070     trcVerbose("Could not open pause file '%s', continuing immediately.", filename);
4071   }
4072 }
4073 
4074 bool os::is_primordial_thread(void) {
4075   if (pthread_self() == (pthread_t)1) {
4076     return true;
4077   } else {
4078     return false;
4079   }
4080 }
4081 
4082 // OS recognitions (PASE/AIX, OS level) call this before calling any
4083 // one of Aix::on_pase(), Aix::os_version() static
4084 void os::Aix::initialize_os_info() {
4085 
4086   assert(_on_pase == -1 && _os_version == 0, "already called.");
4087 
4088   struct utsname uts;
4089   memset(&uts, 0, sizeof(uts));
4090   strcpy(uts.sysname, "?");
4091   if (::uname(&uts) == -1) {
4092     trcVerbose("uname failed (%d)", errno);
4093     guarantee(0, "Could not determine whether we run on AIX or PASE");
4094   } else {
4095     trcVerbose("uname says: sysname \"%s\" version \"%s\" release \"%s\" "
4096                "node \"%s\" machine \"%s\"\n",
4097                uts.sysname, uts.version, uts.release, uts.nodename, uts.machine);
4098     const int major = atoi(uts.version);
4099     assert(major > 0, "invalid OS version");
4100     const int minor = atoi(uts.release);
4101     assert(minor > 0, "invalid OS release");
4102     _os_version = (major << 24) | (minor << 16);
4103     char ver_str[20] = {0};
4104     char *name_str = "unknown OS";
4105     if (strcmp(uts.sysname, "OS400") == 0) {
4106       // We run on AS/400 PASE. We do not support versions older than V5R4M0.
4107       _on_pase = 1;
4108       if (os_version_short() < 0x0504) {
4109         trcVerbose("OS/400 releases older than V5R4M0 not supported.");
4110         assert(false, "OS/400 release too old.");
4111       }
4112       name_str = "OS/400 (pase)";
4113       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u", major, minor);
4114     } else if (strcmp(uts.sysname, "AIX") == 0) {
4115       // We run on AIX. We do not support versions older than AIX 5.3.
4116       _on_pase = 0;
4117       // Determine detailed AIX version: Version, Release, Modification, Fix Level.
4118       odmWrapper::determine_os_kernel_version(&_os_version);
4119       if (os_version_short() < 0x0503) {
4120         trcVerbose("AIX release older than AIX 5.3 not supported.");
4121         assert(false, "AIX release too old.");
4122       }
4123       name_str = "AIX";
4124       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u.%u.%u",
4125                    major, minor, (_os_version >> 8) & 0xFF, _os_version & 0xFF);
4126     } else {
4127       assert(false, name_str);
4128     }
4129     trcVerbose("We run on %s %s", name_str, ver_str);
4130   }
4131 
4132   guarantee(_on_pase != -1 && _os_version, "Could not determine AIX/OS400 release");
4133 } // end: os::Aix::initialize_os_info()
4134 
4135 // Scan environment for important settings which might effect the VM.
4136 // Trace out settings. Warn about invalid settings and/or correct them.
4137 //
4138 // Must run after os::Aix::initialue_os_info().
4139 void os::Aix::scan_environment() {
4140 
4141   char* p;
4142   int rc;
4143 
4144   // Warn explicity if EXTSHM=ON is used. That switch changes how
4145   // System V shared memory behaves. One effect is that page size of
4146   // shared memory cannot be change dynamically, effectivly preventing
4147   // large pages from working.
4148   // This switch was needed on AIX 32bit, but on AIX 64bit the general
4149   // recommendation is (in OSS notes) to switch it off.
4150   p = ::getenv("EXTSHM");
4151   trcVerbose("EXTSHM=%s.", p ? p : "<unset>");
4152   if (p && strcasecmp(p, "ON") == 0) {
4153     _extshm = 1;
4154     trcVerbose("*** Unsupported mode! Please remove EXTSHM from your environment! ***");
4155     if (!AllowExtshm) {
4156       // We allow under certain conditions the user to continue. However, we want this
4157       // to be a fatal error by default. On certain AIX systems, leaving EXTSHM=ON means
4158       // that the VM is not able to allocate 64k pages for the heap.
4159       // We do not want to run with reduced performance.
4160       vm_exit_during_initialization("EXTSHM is ON. Please remove EXTSHM from your environment.");
4161     }
4162   } else {
4163     _extshm = 0;
4164   }
4165 
4166   // SPEC1170 behaviour: will change the behaviour of a number of POSIX APIs.
4167   // Not tested, not supported.
4168   //
4169   // Note that it might be worth the trouble to test and to require it, if only to
4170   // get useful return codes for mprotect.
4171   //
4172   // Note: Setting XPG_SUS_ENV in the process is too late. Must be set earlier (before
4173   // exec() ? before loading the libjvm ? ....)
4174   p = ::getenv("XPG_SUS_ENV");
4175   trcVerbose("XPG_SUS_ENV=%s.", p ? p : "<unset>");
4176   if (p && strcmp(p, "ON") == 0) {
4177     _xpg_sus_mode = 1;
4178     trcVerbose("Unsupported setting: XPG_SUS_ENV=ON");
4179     // This is not supported. Worst of all, it changes behaviour of mmap MAP_FIXED to
4180     // clobber address ranges. If we ever want to support that, we have to do some
4181     // testing first.
4182     guarantee(false, "XPG_SUS_ENV=ON not supported");
4183   } else {
4184     _xpg_sus_mode = 0;
4185   }
4186 
4187   if (os::Aix::on_pase()) {
4188     p = ::getenv("QIBM_MULTI_THREADED");
4189     trcVerbose("QIBM_MULTI_THREADED=%s.", p ? p : "<unset>");
4190   }
4191 
4192   p = ::getenv("LDR_CNTRL");
4193   trcVerbose("LDR_CNTRL=%s.", p ? p : "<unset>");
4194   if (os::Aix::on_pase() && os::Aix::os_version_short() == 0x0701) {
4195     if (p && ::strstr(p, "TEXTPSIZE")) {
4196       trcVerbose("*** WARNING - LDR_CNTRL contains TEXTPSIZE. "
4197         "you may experience hangs or crashes on OS/400 V7R1.");
4198     }
4199   }
4200 
4201   p = ::getenv("AIXTHREAD_GUARDPAGES");
4202   trcVerbose("AIXTHREAD_GUARDPAGES=%s.", p ? p : "<unset>");
4203 
4204 } // end: os::Aix::scan_environment()
4205 
4206 // PASE: initialize the libo4 library (PASE porting library).
4207 void os::Aix::initialize_libo4() {
4208   guarantee(os::Aix::on_pase(), "OS/400 only.");
4209   if (!libo4::init()) {
4210     trcVerbose("libo4 initialization failed.");
4211     assert(false, "libo4 initialization failed");
4212   } else {
4213     trcVerbose("libo4 initialized.");
4214   }
4215 }
4216 
4217 // AIX: initialize the libperfstat library.
4218 void os::Aix::initialize_libperfstat() {
4219   assert(os::Aix::on_aix(), "AIX only");
4220   if (!libperfstat::init()) {
4221     trcVerbose("libperfstat initialization failed.");
4222     assert(false, "libperfstat initialization failed");
4223   } else {
4224     trcVerbose("libperfstat initialized.");
4225   }
4226 }
4227 
4228 /////////////////////////////////////////////////////////////////////////////
4229 // thread stack
4230 
4231 // Get the current stack base from the OS (actually, the pthread library).
4232 // Note: usually not page aligned.
4233 address os::current_stack_base() {
4234   AixMisc::stackbounds_t bounds;
4235   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4236   guarantee(rc, "Unable to retrieve stack bounds.");
4237   return bounds.base;
4238 }
4239 
4240 // Get the current stack size from the OS (actually, the pthread library).
4241 // Returned size is such that (base - size) is always aligned to page size.
4242 size_t os::current_stack_size() {
4243   AixMisc::stackbounds_t bounds;
4244   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4245   guarantee(rc, "Unable to retrieve stack bounds.");
4246   // Align the returned stack size such that the stack low address
4247   // is aligned to page size (Note: base is usually not and we do not care).
4248   // We need to do this because caller code will assume stack low address is
4249   // page aligned and will place guard pages without checking.
4250   address low = bounds.base - bounds.size;
4251   address low_aligned = (address)align_up(low, os::vm_page_size());
4252   size_t s = bounds.base - low_aligned;
4253   return s;
4254 }
4255 
4256 extern char** environ;
4257 
4258 // Run the specified command in a separate process. Return its exit value,
4259 // or -1 on failure (e.g. can't fork a new process).
4260 // Unlike system(), this function can be called from signal handler. It
4261 // doesn't block SIGINT et al.
4262 int os::fork_and_exec(char* cmd) {
4263   char * argv[4] = {"sh", "-c", cmd, NULL};
4264 
4265   pid_t pid = fork();
4266 
4267   if (pid < 0) {
4268     // fork failed
4269     return -1;
4270 
4271   } else if (pid == 0) {
4272     // child process
4273 
4274     // Try to be consistent with system(), which uses "/usr/bin/sh" on AIX.
4275     execve("/usr/bin/sh", argv, environ);
4276 
4277     // execve failed
4278     _exit(-1);
4279 
4280   } else {
4281     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4282     // care about the actual exit code, for now.
4283 
4284     int status;
4285 
4286     // Wait for the child process to exit. This returns immediately if
4287     // the child has already exited. */
4288     while (waitpid(pid, &status, 0) < 0) {
4289       switch (errno) {
4290         case ECHILD: return 0;
4291         case EINTR: break;
4292         default: return -1;
4293       }
4294     }
4295 
4296     if (WIFEXITED(status)) {
4297       // The child exited normally; get its exit code.
4298       return WEXITSTATUS(status);
4299     } else if (WIFSIGNALED(status)) {
4300       // The child exited because of a signal.
4301       // The best value to return is 0x80 + signal number,
4302       // because that is what all Unix shells do, and because
4303       // it allows callers to distinguish between process exit and
4304       // process death by signal.
4305       return 0x80 + WTERMSIG(status);
4306     } else {
4307       // Unknown exit code; pass it through.
4308       return status;
4309     }
4310   }
4311   return -1;
4312 }
4313 
4314 // Get the default path to the core file
4315 // Returns the length of the string
4316 int os::get_core_path(char* buffer, size_t bufferSize) {
4317   const char* p = get_current_directory(buffer, bufferSize);
4318 
4319   if (p == NULL) {
4320     assert(p != NULL, "failed to get current directory");
4321     return 0;
4322   }
4323 
4324   jio_snprintf(buffer, bufferSize, "%s/core or core.%d",
4325                                                p, current_process_id());
4326 
4327   return strlen(buffer);
4328 }
4329 
4330 #ifndef PRODUCT
4331 void TestReserveMemorySpecial_test() {
4332   // No tests available for this platform
4333 }
4334 #endif
4335 
4336 bool os::start_debugging(char *buf, int buflen) {
4337   int len = (int)strlen(buf);
4338   char *p = &buf[len];
4339 
4340   jio_snprintf(p, buflen -len,
4341                  "\n\n"
4342                  "Do you want to debug the problem?\n\n"
4343                  "To debug, run 'dbx -a %d'; then switch to thread tid " INTX_FORMAT ", k-tid " INTX_FORMAT "\n"
4344                  "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
4345                  "Otherwise, press RETURN to abort...",
4346                  os::current_process_id(),
4347                  os::current_thread_id(), thread_self());
4348 
4349   bool yes = os::message_box("Unexpected Error", buf);
4350 
4351   if (yes) {
4352     // yes, user asked VM to launch debugger
4353     jio_snprintf(buf, buflen, "dbx -a %d", os::current_process_id());
4354 
4355     os::fork_and_exec(buf);
4356     yes = false;
4357   }
4358   return yes;
4359 }
4360 
4361 static inline time_t get_mtime(const char* filename) {
4362   struct stat st;
4363   int ret = os::stat(filename, &st);
4364   assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
4365   return st.st_mtime;
4366 }
4367 
4368 int os::compare_file_modified_times(const char* file1, const char* file2) {
4369   time_t t1 = get_mtime(file1);
4370   time_t t2 = get_mtime(file2);
4371   return t1 - t2;
4372 }