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