1 /*
   2  * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2019 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 "logging/logStream.hpp"
  41 #include "libo4.hpp"
  42 #include "libperfstat_aix.hpp"
  43 #include "libodm_aix.hpp"
  44 #include "loadlib_aix.hpp"
  45 #include "memory/allocation.inline.hpp"
  46 #include "memory/filemap.hpp"
  47 #include "misc_aix.hpp"
  48 #include "oops/oop.inline.hpp"
  49 #include "os_aix.inline.hpp"
  50 #include "os_share_aix.hpp"
  51 #include "porting_aix.hpp"
  52 #include "prims/jniFastGetField.hpp"
  53 #include "prims/jvm_misc.hpp"
  54 #include "runtime/arguments.hpp"
  55 #include "runtime/atomic.hpp"
  56 #include "runtime/extendedPC.hpp"
  57 #include "runtime/globals.hpp"
  58 #include "runtime/interfaceSupport.inline.hpp"
  59 #include "runtime/java.hpp"
  60 #include "runtime/javaCalls.hpp"
  61 #include "runtime/mutexLocker.hpp"
  62 #include "runtime/objectMonitor.hpp"
  63 #include "runtime/orderAccess.hpp"
  64 #include "runtime/os.hpp"
  65 #include "runtime/osThread.hpp"
  66 #include "runtime/perfMemory.hpp"
  67 #include "runtime/sharedRuntime.hpp"
  68 #include "runtime/statSampler.hpp"
  69 #include "runtime/stubRoutines.hpp"
  70 #include "runtime/thread.inline.hpp"
  71 #include "runtime/threadCritical.hpp"
  72 #include "runtime/timer.hpp"
  73 #include "runtime/vm_version.hpp"
  74 #include "services/attachListener.hpp"
  75 #include "services/runtimeService.hpp"
  76 #include "utilities/align.hpp"
  77 #include "utilities/decoder.hpp"
  78 #include "utilities/defaultStream.hpp"
  79 #include "utilities/events.hpp"
  80 #include "utilities/growableArray.hpp"
  81 #include "utilities/vmError.hpp"
  82 
  83 // put OS-includes here (sorted alphabetically)
  84 #include <errno.h>
  85 #include <fcntl.h>
  86 #include <inttypes.h>
  87 #include <poll.h>
  88 #include <procinfo.h>
  89 #include <pthread.h>
  90 #include <pwd.h>
  91 #include <semaphore.h>
  92 #include <signal.h>
  93 #include <stdint.h>
  94 #include <stdio.h>
  95 #include <string.h>
  96 #include <unistd.h>
  97 #include <sys/ioctl.h>
  98 #include <sys/ipc.h>
  99 #include <sys/mman.h>
 100 #include <sys/resource.h>
 101 #include <sys/select.h>
 102 #include <sys/shm.h>
 103 #include <sys/socket.h>
 104 #include <sys/stat.h>
 105 #include <sys/sysinfo.h>
 106 #include <sys/systemcfg.h>
 107 #include <sys/time.h>
 108 #include <sys/times.h>
 109 #include <sys/types.h>
 110 #include <sys/utsname.h>
 111 #include <sys/vminfo.h>
 112 #include <sys/wait.h>
 113 
 114 // Missing prototypes for various system APIs.
 115 extern "C"
 116 int mread_real_time(timebasestruct_t *t, size_t size_of_timebasestruct_t);
 117 
 118 #if !defined(_AIXVERSION_610)
 119 extern "C" int getthrds64(pid_t, struct thrdentry64*, int, tid64_t*, int);
 120 extern "C" int getprocs64(procentry64*, int, fdsinfo*, int, pid_t*, int);
 121 extern "C" int getargs(procsinfo*, int, char*, int);
 122 #endif
 123 
 124 #define MAX_PATH (2 * K)
 125 
 126 // for timer info max values which include all bits
 127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 128 // for multipage initialization error analysis (in 'g_multipage_error')
 129 #define ERROR_MP_OS_TOO_OLD                          100
 130 #define ERROR_MP_EXTSHM_ACTIVE                       101
 131 #define ERROR_MP_VMGETINFO_FAILED                    102
 132 #define ERROR_MP_VMGETINFO_CLAIMS_NO_SUPPORT_FOR_64K 103
 133 
 134 // excerpts from systemcfg.h that might be missing on older os levels
 135 #ifndef PV_5_Compat
 136   #define PV_5_Compat 0x0F8000   /* Power PC 5 */
 137 #endif
 138 #ifndef PV_6
 139   #define PV_6 0x100000          /* Power PC 6 */
 140 #endif
 141 #ifndef PV_6_1
 142   #define PV_6_1 0x100001        /* Power PC 6 DD1.x */
 143 #endif
 144 #ifndef PV_6_Compat
 145   #define PV_6_Compat 0x108000   /* Power PC 6 */
 146 #endif
 147 #ifndef PV_7
 148   #define PV_7 0x200000          /* Power PC 7 */
 149 #endif
 150 #ifndef PV_7_Compat
 151   #define PV_7_Compat 0x208000   /* Power PC 7 */
 152 #endif
 153 #ifndef PV_8
 154   #define PV_8 0x300000          /* Power PC 8 */
 155 #endif
 156 #ifndef PV_8_Compat
 157   #define PV_8_Compat 0x308000   /* Power PC 8 */
 158 #endif
 159 
 160 static address resolve_function_descriptor_to_code_pointer(address p);
 161 
 162 static void vmembk_print_on(outputStream* os);
 163 
 164 ////////////////////////////////////////////////////////////////////////////////
 165 // global variables (for a description see os_aix.hpp)
 166 
 167 julong    os::Aix::_physical_memory = 0;
 168 
 169 pthread_t os::Aix::_main_thread = ((pthread_t)0);
 170 int       os::Aix::_page_size = -1;
 171 
 172 // -1 = uninitialized, 0 if AIX, 1 if OS/400 pase
 173 int       os::Aix::_on_pase = -1;
 174 
 175 // 0 = uninitialized, otherwise 32 bit number:
 176 //  0xVVRRTTSS
 177 //  VV - major version
 178 //  RR - minor version
 179 //  TT - tech level, if known, 0 otherwise
 180 //  SS - service pack, if known, 0 otherwise
 181 uint32_t  os::Aix::_os_version = 0;
 182 
 183 // -1 = uninitialized, 0 - no, 1 - yes
 184 int       os::Aix::_xpg_sus_mode = -1;
 185 
 186 // -1 = uninitialized, 0 - no, 1 - yes
 187 int       os::Aix::_extshm = -1;
 188 
 189 ////////////////////////////////////////////////////////////////////////////////
 190 // local variables
 191 
 192 static volatile jlong max_real_time = 0;
 193 static jlong    initial_time_count = 0;
 194 static int      clock_tics_per_sec = 100;
 195 static sigset_t check_signal_done;         // For diagnostics to print a message once (see run_periodic_checks)
 196 static bool     check_signals      = true;
 197 static int      SR_signum          = SIGUSR2; // Signal used to suspend/resume a thread (must be > SIGSEGV, see 4355769)
 198 static sigset_t SR_sigset;
 199 
 200 // Process break recorded at startup.
 201 static address g_brk_at_startup = NULL;
 202 
 203 // This describes the state of multipage support of the underlying
 204 // OS. Note that this is of no interest to the outsize world and
 205 // therefore should not be defined in AIX class.
 206 //
 207 // AIX supports four different page sizes - 4K, 64K, 16MB, 16GB. The
 208 // latter two (16M "large" resp. 16G "huge" pages) require special
 209 // setup and are normally not available.
 210 //
 211 // AIX supports multiple page sizes per process, for:
 212 //  - Stack (of the primordial thread, so not relevant for us)
 213 //  - Data - data, bss, heap, for us also pthread stacks
 214 //  - Text - text code
 215 //  - shared memory
 216 //
 217 // Default page sizes can be set via linker options (-bdatapsize, -bstacksize, ...)
 218 // and via environment variable LDR_CNTRL (DATAPSIZE, STACKPSIZE, ...).
 219 //
 220 // For shared memory, page size can be set dynamically via
 221 // shmctl(). Different shared memory regions can have different page
 222 // sizes.
 223 //
 224 // More information can be found at AIBM info center:
 225 //   http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/multiple_page_size_app_support.htm
 226 //
 227 static struct {
 228   size_t pagesize;            // sysconf _SC_PAGESIZE (4K)
 229   size_t datapsize;           // default data page size (LDR_CNTRL DATAPSIZE)
 230   size_t shmpsize;            // default shared memory page size (LDR_CNTRL SHMPSIZE)
 231   size_t pthr_stack_pagesize; // stack page size of pthread threads
 232   size_t textpsize;           // default text page size (LDR_CNTRL STACKPSIZE)
 233   bool can_use_64K_pages;     // True if we can alloc 64K pages dynamically with Sys V shm.
 234   bool can_use_16M_pages;     // True if we can alloc 16M pages dynamically with Sys V shm.
 235   int error;                  // Error describing if something went wrong at multipage init.
 236 } g_multipage_support = {
 237   (size_t) -1,
 238   (size_t) -1,
 239   (size_t) -1,
 240   (size_t) -1,
 241   (size_t) -1,
 242   false, false,
 243   0
 244 };
 245 
 246 // We must not accidentally allocate memory close to the BRK - even if
 247 // that would work - because then we prevent the BRK segment from
 248 // growing which may result in a malloc OOM even though there is
 249 // enough memory. The problem only arises if we shmat() or mmap() at
 250 // a specific wish address, e.g. to place the heap in a
 251 // compressed-oops-friendly way.
 252 static bool is_close_to_brk(address a) {
 253   assert0(g_brk_at_startup != NULL);
 254   if (a >= g_brk_at_startup &&
 255       a < (g_brk_at_startup + MaxExpectedDataSegmentSize)) {
 256     return true;
 257   }
 258   return false;
 259 }
 260 
 261 julong os::available_memory() {
 262   return Aix::available_memory();
 263 }
 264 
 265 julong os::Aix::available_memory() {
 266   // Avoid expensive API call here, as returned value will always be null.
 267   if (os::Aix::on_pase()) {
 268     return 0x0LL;
 269   }
 270   os::Aix::meminfo_t mi;
 271   if (os::Aix::get_meminfo(&mi)) {
 272     return mi.real_free;
 273   } else {
 274     return ULONG_MAX;
 275   }
 276 }
 277 
 278 julong os::physical_memory() {
 279   return Aix::physical_memory();
 280 }
 281 
 282 // Return true if user is running as root.
 283 
 284 bool os::have_special_privileges() {
 285   static bool init = false;
 286   static bool privileges = false;
 287   if (!init) {
 288     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 289     init = true;
 290   }
 291   return privileges;
 292 }
 293 
 294 // Helper function, emulates disclaim64 using multiple 32bit disclaims
 295 // because we cannot use disclaim64() on AS/400 and old AIX releases.
 296 static bool my_disclaim64(char* addr, size_t size) {
 297 
 298   if (size == 0) {
 299     return true;
 300   }
 301 
 302   // Maximum size 32bit disclaim() accepts. (Theoretically 4GB, but I just do not trust that.)
 303   const unsigned int maxDisclaimSize = 0x40000000;
 304 
 305   const unsigned int numFullDisclaimsNeeded = (size / maxDisclaimSize);
 306   const unsigned int lastDisclaimSize = (size % maxDisclaimSize);
 307 
 308   char* p = addr;
 309 
 310   for (int i = 0; i < numFullDisclaimsNeeded; i ++) {
 311     if (::disclaim(p, maxDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 312       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + maxDisclaimSize, errno);
 313       return false;
 314     }
 315     p += maxDisclaimSize;
 316   }
 317 
 318   if (lastDisclaimSize > 0) {
 319     if (::disclaim(p, lastDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 320       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + lastDisclaimSize, errno);
 321       return false;
 322     }
 323   }
 324 
 325   return true;
 326 }
 327 
 328 // Cpu architecture string
 329 #if defined(PPC32)
 330 static char cpu_arch[] = "ppc";
 331 #elif defined(PPC64)
 332 static char cpu_arch[] = "ppc64";
 333 #else
 334 #error Add appropriate cpu_arch setting
 335 #endif
 336 
 337 // Wrap the function "vmgetinfo" which is not available on older OS releases.
 338 static int checked_vmgetinfo(void *out, int command, int arg) {
 339   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 340     guarantee(false, "cannot call vmgetinfo on AS/400 older than V6R1");
 341   }
 342   return ::vmgetinfo(out, command, arg);
 343 }
 344 
 345 // Given an address, returns the size of the page backing that address.
 346 size_t os::Aix::query_pagesize(void* addr) {
 347 
 348   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 349     // AS/400 older than V6R1: no vmgetinfo here, default to 4K
 350     return 4*K;
 351   }
 352 
 353   vm_page_info pi;
 354   pi.addr = (uint64_t)addr;
 355   if (checked_vmgetinfo(&pi, VM_PAGE_INFO, sizeof(pi)) == 0) {
 356     return pi.pagesize;
 357   } else {
 358     assert(false, "vmgetinfo failed to retrieve page size");
 359     return 4*K;
 360   }
 361 }
 362 
 363 void os::Aix::initialize_system_info() {
 364 
 365   // Get the number of online(logical) cpus instead of configured.
 366   os::_processor_count = sysconf(_SC_NPROCESSORS_ONLN);
 367   assert(_processor_count > 0, "_processor_count must be > 0");
 368 
 369   // Retrieve total physical storage.
 370   os::Aix::meminfo_t mi;
 371   if (!os::Aix::get_meminfo(&mi)) {
 372     assert(false, "os::Aix::get_meminfo failed.");
 373   }
 374   _physical_memory = (julong) mi.real_total;
 375 }
 376 
 377 // Helper function for tracing page sizes.
 378 static const char* describe_pagesize(size_t pagesize) {
 379   switch (pagesize) {
 380     case 4*K : return "4K";
 381     case 64*K: return "64K";
 382     case 16*M: return "16M";
 383     case 16*G: return "16G";
 384     default:
 385       assert(false, "surprise");
 386       return "??";
 387   }
 388 }
 389 
 390 // Probe OS for multipage support.
 391 // Will fill the global g_multipage_support structure.
 392 // Must be called before calling os::large_page_init().
 393 static void query_multipage_support() {
 394 
 395   guarantee(g_multipage_support.pagesize == -1,
 396             "do not call twice");
 397 
 398   g_multipage_support.pagesize = ::sysconf(_SC_PAGESIZE);
 399 
 400   // This really would surprise me.
 401   assert(g_multipage_support.pagesize == 4*K, "surprise!");
 402 
 403   // Query default data page size (default page size for C-Heap, pthread stacks and .bss).
 404   // Default data page size is defined either by linker options (-bdatapsize)
 405   // or by environment variable LDR_CNTRL (suboption DATAPSIZE). If none is given,
 406   // default should be 4K.
 407   {
 408     void* p = ::malloc(16*M);
 409     g_multipage_support.datapsize = os::Aix::query_pagesize(p);
 410     ::free(p);
 411   }
 412 
 413   // Query default shm page size (LDR_CNTRL SHMPSIZE).
 414   // Note that this is pure curiosity. We do not rely on default page size but set
 415   // our own page size after allocated.
 416   {
 417     const int shmid = ::shmget(IPC_PRIVATE, 1, IPC_CREAT | S_IRUSR | S_IWUSR);
 418     guarantee(shmid != -1, "shmget failed");
 419     void* p = ::shmat(shmid, NULL, 0);
 420     ::shmctl(shmid, IPC_RMID, NULL);
 421     guarantee(p != (void*) -1, "shmat failed");
 422     g_multipage_support.shmpsize = os::Aix::query_pagesize(p);
 423     ::shmdt(p);
 424   }
 425 
 426   // Before querying the stack page size, make sure we are not running as primordial
 427   // thread (because primordial thread's stack may have different page size than
 428   // pthread thread stacks). Running a VM on the primordial thread won't work for a
 429   // number of reasons so we may just as well guarantee it here.
 430   guarantee0(!os::is_primordial_thread());
 431 
 432   // Query pthread stack page size. Should be the same as data page size because
 433   // pthread stacks are allocated from C-Heap.
 434   {
 435     int dummy = 0;
 436     g_multipage_support.pthr_stack_pagesize = os::Aix::query_pagesize(&dummy);
 437   }
 438 
 439   // Query default text page size (LDR_CNTRL TEXTPSIZE).
 440   {
 441     address any_function =
 442       resolve_function_descriptor_to_code_pointer((address)describe_pagesize);
 443     g_multipage_support.textpsize = os::Aix::query_pagesize(any_function);
 444   }
 445 
 446   // Now probe for support of 64K pages and 16M pages.
 447 
 448   // Before OS/400 V6R1, there is no support for pages other than 4K.
 449   if (os::Aix::on_pase_V5R4_or_older()) {
 450     trcVerbose("OS/400 < V6R1 - no large page support.");
 451     g_multipage_support.error = ERROR_MP_OS_TOO_OLD;
 452     goto query_multipage_support_end;
 453   }
 454 
 455   // Now check which page sizes the OS claims it supports, and of those, which actually can be used.
 456   {
 457     const int MAX_PAGE_SIZES = 4;
 458     psize_t sizes[MAX_PAGE_SIZES];
 459     const int num_psizes = checked_vmgetinfo(sizes, VMINFO_GETPSIZES, MAX_PAGE_SIZES);
 460     if (num_psizes == -1) {
 461       trcVerbose("vmgetinfo(VMINFO_GETPSIZES) failed (errno: %d)", errno);
 462       trcVerbose("disabling multipage support.");
 463       g_multipage_support.error = ERROR_MP_VMGETINFO_FAILED;
 464       goto query_multipage_support_end;
 465     }
 466     guarantee(num_psizes > 0, "vmgetinfo(.., VMINFO_GETPSIZES, ...) failed.");
 467     assert(num_psizes <= MAX_PAGE_SIZES, "Surprise! more than 4 page sizes?");
 468     trcVerbose("vmgetinfo(.., VMINFO_GETPSIZES, ...) returns %d supported page sizes: ", num_psizes);
 469     for (int i = 0; i < num_psizes; i ++) {
 470       trcVerbose(" %s ", describe_pagesize(sizes[i]));
 471     }
 472 
 473     // Can we use 64K, 16M pages?
 474     for (int i = 0; i < num_psizes; i ++) {
 475       const size_t pagesize = sizes[i];
 476       if (pagesize != 64*K && pagesize != 16*M) {
 477         continue;
 478       }
 479       bool can_use = false;
 480       trcVerbose("Probing support for %s pages...", describe_pagesize(pagesize));
 481       const int shmid = ::shmget(IPC_PRIVATE, pagesize,
 482         IPC_CREAT | S_IRUSR | S_IWUSR);
 483       guarantee0(shmid != -1); // Should always work.
 484       // Try to set pagesize.
 485       struct shmid_ds shm_buf = { 0 };
 486       shm_buf.shm_pagesize = pagesize;
 487       if (::shmctl(shmid, SHM_PAGESIZE, &shm_buf) != 0) {
 488         const int en = errno;
 489         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 490         trcVerbose("shmctl(SHM_PAGESIZE) failed with errno=%d", 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 (" SIZE_FORMAT_HEX ") 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 = 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 = 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     // Log some OS information which might explain why creating the thread failed.
 927     log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
 928     LogStream st(Log(os, thread)::info());
 929     os::Posix::print_rlimit_info(&st);
 930     os::print_memory_info(&st);
 931   }
 932 
 933   pthread_attr_destroy(&attr);
 934 
 935   if (ret != 0) {
 936     // Need to clean up stuff we've allocated so far.
 937     thread->set_osthread(NULL);
 938     delete osthread;
 939     return false;
 940   }
 941 
 942   // OSThread::thread_id is the pthread id.
 943   osthread->set_thread_id(tid);
 944 
 945   return true;
 946 }
 947 
 948 /////////////////////////////////////////////////////////////////////////////
 949 // attach existing thread
 950 
 951 // bootstrap the main thread
 952 bool os::create_main_thread(JavaThread* thread) {
 953   assert(os::Aix::_main_thread == pthread_self(), "should be called inside main thread");
 954   return create_attached_thread(thread);
 955 }
 956 
 957 bool os::create_attached_thread(JavaThread* thread) {
 958 #ifdef ASSERT
 959     thread->verify_not_published();
 960 #endif
 961 
 962   // Allocate the OSThread object
 963   OSThread* osthread = new OSThread(NULL, NULL);
 964 
 965   if (osthread == NULL) {
 966     return false;
 967   }
 968 
 969   const pthread_t pthread_id = ::pthread_self();
 970   const tid_t kernel_thread_id = ::thread_self();
 971 
 972   // OSThread::thread_id is the pthread id.
 973   osthread->set_thread_id(pthread_id);
 974 
 975   // .. but keep kernel thread id too for diagnostics
 976   osthread->set_kernel_thread_id(kernel_thread_id);
 977 
 978   // initialize floating point control register
 979   os::Aix::init_thread_fpu_state();
 980 
 981   // Initial thread state is RUNNABLE
 982   osthread->set_state(RUNNABLE);
 983 
 984   thread->set_osthread(osthread);
 985 
 986   if (UseNUMA) {
 987     int lgrp_id = os::numa_get_group_id();
 988     if (lgrp_id != -1) {
 989       thread->set_lgrp_id(lgrp_id);
 990     }
 991   }
 992 
 993   // initialize signal mask for this thread
 994   // and save the caller's signal mask
 995   os::Aix::hotspot_sigmask(thread);
 996 
 997   log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 998     os::current_thread_id(), (uintx) kernel_thread_id);
 999 
1000   return true;
1001 }
1002 
1003 void os::pd_start_thread(Thread* thread) {
1004   int status = pthread_continue_np(thread->osthread()->pthread_id());
1005   assert(status == 0, "thr_continue failed");
1006 }
1007 
1008 // Free OS resources related to the OSThread
1009 void os::free_thread(OSThread* osthread) {
1010   assert(osthread != NULL, "osthread not set");
1011 
1012   // We are told to free resources of the argument thread,
1013   // but we can only really operate on the current thread.
1014   assert(Thread::current()->osthread() == osthread,
1015          "os::free_thread but not current thread");
1016 
1017   // Restore caller's signal mask
1018   sigset_t sigmask = osthread->caller_sigmask();
1019   pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1020 
1021   delete osthread;
1022 }
1023 
1024 ////////////////////////////////////////////////////////////////////////////////
1025 // time support
1026 
1027 // Time since start-up in seconds to a fine granularity.
1028 // Used by VMSelfDestructTimer and the MemProfiler.
1029 double os::elapsedTime() {
1030   return (double)(os::elapsed_counter()) * 0.000001;
1031 }
1032 
1033 jlong os::elapsed_counter() {
1034   timeval time;
1035   int status = gettimeofday(&time, NULL);
1036   return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1037 }
1038 
1039 jlong os::elapsed_frequency() {
1040   return (1000 * 1000);
1041 }
1042 
1043 bool os::supports_vtime() { return true; }
1044 bool os::enable_vtime()   { return false; }
1045 bool os::vtime_enabled()  { return false; }
1046 
1047 double os::elapsedVTime() {
1048   struct rusage usage;
1049   int retval = getrusage(RUSAGE_THREAD, &usage);
1050   if (retval == 0) {
1051     return usage.ru_utime.tv_sec + usage.ru_stime.tv_sec + (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000.0 * 1000);
1052   } else {
1053     // better than nothing, but not much
1054     return elapsedTime();
1055   }
1056 }
1057 
1058 jlong os::javaTimeMillis() {
1059   timeval time;
1060   int status = gettimeofday(&time, NULL);
1061   assert(status != -1, "aix error at gettimeofday()");
1062   return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1063 }
1064 
1065 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1066   timeval time;
1067   int status = gettimeofday(&time, NULL);
1068   assert(status != -1, "aix error at gettimeofday()");
1069   seconds = jlong(time.tv_sec);
1070   nanos = jlong(time.tv_usec) * 1000;
1071 }
1072 
1073 // We use mread_real_time here.
1074 // On AIX: If the CPU has a time register, the result will be RTC_POWER and
1075 // it has to be converted to real time. AIX documentations suggests to do
1076 // this unconditionally, so we do it.
1077 //
1078 // See: https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf2/read_real_time.htm
1079 //
1080 // On PASE: mread_real_time will always return RTC_POWER_PC data, so no
1081 // conversion is necessary. However, mread_real_time will not return
1082 // monotonic results but merely matches read_real_time. So we need a tweak
1083 // to ensure monotonic results.
1084 //
1085 // For PASE no public documentation exists, just word by IBM
1086 jlong os::javaTimeNanos() {
1087   timebasestruct_t time;
1088   int rc = mread_real_time(&time, TIMEBASE_SZ);
1089   if (os::Aix::on_pase()) {
1090     assert(rc == RTC_POWER, "expected time format RTC_POWER from mread_real_time in PASE");
1091     jlong now = jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1092     jlong prev = max_real_time;
1093     if (now <= prev) {
1094       return prev;   // same or retrograde time;
1095     }
1096     jlong obsv = Atomic::cmpxchg(now, &max_real_time, prev);
1097     assert(obsv >= prev, "invariant");   // Monotonicity
1098     // If the CAS succeeded then we're done and return "now".
1099     // If the CAS failed and the observed value "obsv" is >= now then
1100     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1101     // some other thread raced this thread and installed a new value, in which case
1102     // we could either (a) retry the entire operation, (b) retry trying to install now
1103     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1104     // we might discard a higher "now" value in deference to a slightly lower but freshly
1105     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1106     // to (a) or (b) -- and greatly reduces coherence traffic.
1107     // We might also condition (c) on the magnitude of the delta between obsv and now.
1108     // Avoiding excessive CAS operations to hot RW locations is critical.
1109     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1110     return (prev == obsv) ? now : obsv;
1111   } else {
1112     if (rc != RTC_POWER) {
1113       rc = time_base_to_time(&time, TIMEBASE_SZ);
1114       assert(rc != -1, "error calling time_base_to_time()");
1115     }
1116     return jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1117   }
1118 }
1119 
1120 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1121   info_ptr->max_value = ALL_64_BITS;
1122   // mread_real_time() is monotonic (see 'os::javaTimeNanos()')
1123   info_ptr->may_skip_backward = false;
1124   info_ptr->may_skip_forward = false;
1125   info_ptr->kind = JVMTI_TIMER_ELAPSED;    // elapsed not CPU time
1126 }
1127 
1128 // Return the real, user, and system times in seconds from an
1129 // arbitrary fixed point in the past.
1130 bool os::getTimesSecs(double* process_real_time,
1131                       double* process_user_time,
1132                       double* process_system_time) {
1133   struct tms ticks;
1134   clock_t real_ticks = times(&ticks);
1135 
1136   if (real_ticks == (clock_t) (-1)) {
1137     return false;
1138   } else {
1139     double ticks_per_second = (double) clock_tics_per_sec;
1140     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1141     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1142     *process_real_time = ((double) real_ticks) / ticks_per_second;
1143 
1144     return true;
1145   }
1146 }
1147 
1148 char * os::local_time_string(char *buf, size_t buflen) {
1149   struct tm t;
1150   time_t long_time;
1151   time(&long_time);
1152   localtime_r(&long_time, &t);
1153   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1154                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1155                t.tm_hour, t.tm_min, t.tm_sec);
1156   return buf;
1157 }
1158 
1159 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1160   return localtime_r(clock, res);
1161 }
1162 
1163 ////////////////////////////////////////////////////////////////////////////////
1164 // runtime exit support
1165 
1166 // Note: os::shutdown() might be called very early during initialization, or
1167 // called from signal handler. Before adding something to os::shutdown(), make
1168 // sure it is async-safe and can handle partially initialized VM.
1169 void os::shutdown() {
1170 
1171   // allow PerfMemory to attempt cleanup of any persistent resources
1172   perfMemory_exit();
1173 
1174   // needs to remove object in file system
1175   AttachListener::abort();
1176 
1177   // flush buffered output, finish log files
1178   ostream_abort();
1179 
1180   // Check for abort hook
1181   abort_hook_t abort_hook = Arguments::abort_hook();
1182   if (abort_hook != NULL) {
1183     abort_hook();
1184   }
1185 }
1186 
1187 // Note: os::abort() might be called very early during initialization, or
1188 // called from signal handler. Before adding something to os::abort(), make
1189 // sure it is async-safe and can handle partially initialized VM.
1190 void os::abort(bool dump_core, void* siginfo, const void* context) {
1191   os::shutdown();
1192   if (dump_core) {
1193 #ifndef PRODUCT
1194     fdStream out(defaultStream::output_fd());
1195     out.print_raw("Current thread is ");
1196     char buf[16];
1197     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1198     out.print_raw_cr(buf);
1199     out.print_raw_cr("Dumping core ...");
1200 #endif
1201     ::abort(); // dump core
1202   }
1203 
1204   ::exit(1);
1205 }
1206 
1207 // Die immediately, no exit hook, no abort hook, no cleanup.
1208 // Dump a core file, if possible, for debugging.
1209 void os::die() {
1210   if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1211     // For TimeoutInErrorHandlingTest.java, we just kill the VM
1212     // and don't take the time to generate a core file.
1213     os::signal_raise(SIGKILL);
1214   } else {
1215     ::abort();
1216   }
1217 }
1218 
1219 intx os::current_thread_id() {
1220   return (intx)pthread_self();
1221 }
1222 
1223 int os::current_process_id() {
1224   return getpid();
1225 }
1226 
1227 // DLL functions
1228 
1229 const char* os::dll_file_extension() { return ".so"; }
1230 
1231 // This must be hard coded because it's the system's temporary
1232 // directory not the java application's temp directory, ala java.io.tmpdir.
1233 const char* os::get_temp_directory() { return "/tmp"; }
1234 
1235 // Check if addr is inside libjvm.so.
1236 bool os::address_is_in_vm(address addr) {
1237 
1238   // Input could be a real pc or a function pointer literal. The latter
1239   // would be a function descriptor residing in the data segment of a module.
1240   loaded_module_t lm;
1241   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL) {
1242     return lm.is_in_vm;
1243   } else if (LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
1244     return lm.is_in_vm;
1245   } else {
1246     return false;
1247   }
1248 
1249 }
1250 
1251 // Resolve an AIX function descriptor literal to a code pointer.
1252 // If the input is a valid code pointer to a text segment of a loaded module,
1253 //   it is returned unchanged.
1254 // If the input is a valid AIX function descriptor, it is resolved to the
1255 //   code entry point.
1256 // If the input is neither a valid function descriptor nor a valid code pointer,
1257 //   NULL is returned.
1258 static address resolve_function_descriptor_to_code_pointer(address p) {
1259 
1260   if (LoadedLibraries::find_for_text_address(p, NULL) != NULL) {
1261     // It is a real code pointer.
1262     return p;
1263   } else if (LoadedLibraries::find_for_data_address(p, NULL) != NULL) {
1264     // Pointer to data segment, potential function descriptor.
1265     address code_entry = (address)(((FunctionDescriptor*)p)->entry());
1266     if (LoadedLibraries::find_for_text_address(code_entry, NULL) != NULL) {
1267       // It is a function descriptor.
1268       return code_entry;
1269     }
1270   }
1271 
1272   return NULL;
1273 }
1274 
1275 bool os::dll_address_to_function_name(address addr, char *buf,
1276                                       int buflen, int *offset,
1277                                       bool demangle) {
1278   if (offset) {
1279     *offset = -1;
1280   }
1281   // Buf is not optional, but offset is optional.
1282   assert(buf != NULL, "sanity check");
1283   buf[0] = '\0';
1284 
1285   // Resolve function ptr literals first.
1286   addr = resolve_function_descriptor_to_code_pointer(addr);
1287   if (!addr) {
1288     return false;
1289   }
1290 
1291   return AixSymbols::get_function_name(addr, buf, buflen, offset, NULL, demangle);
1292 }
1293 
1294 bool os::dll_address_to_library_name(address addr, char* buf,
1295                                      int buflen, int* offset) {
1296   if (offset) {
1297     *offset = -1;
1298   }
1299   // Buf is not optional, but offset is optional.
1300   assert(buf != NULL, "sanity check");
1301   buf[0] = '\0';
1302 
1303   // Resolve function ptr literals first.
1304   addr = resolve_function_descriptor_to_code_pointer(addr);
1305   if (!addr) {
1306     return false;
1307   }
1308 
1309   return AixSymbols::get_module_name(addr, buf, buflen);
1310 }
1311 
1312 // Loads .dll/.so and in case of error it checks if .dll/.so was built
1313 // for the same architecture as Hotspot is running on.
1314 void *os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1315 
1316   log_info(os)("attempting shared library load of %s", filename);
1317 
1318   if (ebuf && ebuflen > 0) {
1319     ebuf[0] = '\0';
1320     ebuf[ebuflen - 1] = '\0';
1321   }
1322 
1323   if (!filename || strlen(filename) == 0) {
1324     ::strncpy(ebuf, "dll_load: empty filename specified", ebuflen - 1);
1325     return NULL;
1326   }
1327 
1328   // RTLD_LAZY is currently not implemented. The dl is loaded immediately with all its dependants.
1329   void * result= ::dlopen(filename, RTLD_LAZY);
1330   if (result != NULL) {
1331     Events::log(NULL, "Loaded shared library %s", filename);
1332     // Reload dll cache. Don't do this in signal handling.
1333     LoadedLibraries::reload();
1334     log_info(os)("shared library load of %s was successful", filename);
1335     return result;
1336   } else {
1337     // error analysis when dlopen fails
1338     const char* error_report = ::dlerror();
1339     if (error_report == NULL) {
1340       error_report = "dlerror returned no error description";
1341     }
1342     if (ebuf != NULL && ebuflen > 0) {
1343       snprintf(ebuf, ebuflen - 1, "%s, LIBPATH=%s, LD_LIBRARY_PATH=%s : %s",
1344                filename, ::getenv("LIBPATH"), ::getenv("LD_LIBRARY_PATH"), error_report);
1345     }
1346     Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1347     log_info(os)("shared library load of %s failed, %s", filename, error_report);
1348   }
1349   return NULL;
1350 }
1351 
1352 void* os::dll_lookup(void* handle, const char* name) {
1353   void* res = dlsym(handle, name);
1354   return res;
1355 }
1356 
1357 void* os::get_default_process_handle() {
1358   return (void*)::dlopen(NULL, RTLD_LAZY);
1359 }
1360 
1361 void os::print_dll_info(outputStream *st) {
1362   st->print_cr("Dynamic libraries:");
1363   LoadedLibraries::print(st);
1364 }
1365 
1366 void os::get_summary_os_info(char* buf, size_t buflen) {
1367   // There might be something more readable than uname results for AIX.
1368   struct utsname name;
1369   uname(&name);
1370   snprintf(buf, buflen, "%s %s", name.release, name.version);
1371 }
1372 
1373 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1374   // Not yet implemented.
1375   return 0;
1376 }
1377 
1378 void os::print_os_info_brief(outputStream* st) {
1379   uint32_t ver = os::Aix::os_version();
1380   st->print_cr("AIX kernel version %u.%u.%u.%u",
1381                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1382 
1383   os::Posix::print_uname_info(st);
1384 
1385   // Linux uses print_libversion_info(st); here.
1386 }
1387 
1388 void os::print_os_info(outputStream* st) {
1389   st->print("OS:");
1390 
1391   st->print("uname:");
1392   struct utsname name;
1393   uname(&name);
1394   st->print(name.sysname); st->print(" ");
1395   st->print(name.nodename); st->print(" ");
1396   st->print(name.release); st->print(" ");
1397   st->print(name.version); st->print(" ");
1398   st->print(name.machine);
1399   st->cr();
1400 
1401   uint32_t ver = os::Aix::os_version();
1402   st->print_cr("AIX kernel version %u.%u.%u.%u",
1403                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1404 
1405   os::Posix::print_rlimit_info(st);
1406 
1407   // _SC_THREAD_THREADS_MAX is the maximum number of threads within a process.
1408   long tmax = sysconf(_SC_THREAD_THREADS_MAX);
1409   st->print_cr("maximum #threads within a process:%ld", tmax);
1410 
1411   // load average
1412   st->print("load average:");
1413   double loadavg[3] = {-1.L, -1.L, -1.L};
1414   os::loadavg(loadavg, 3);
1415   st->print_cr("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1416 
1417   // print wpar info
1418   libperfstat::wparinfo_t wi;
1419   if (libperfstat::get_wparinfo(&wi)) {
1420     st->print_cr("wpar info");
1421     st->print_cr("name: %s", wi.name);
1422     st->print_cr("id:   %d", wi.wpar_id);
1423     st->print_cr("type: %s", (wi.app_wpar ? "application" : "system"));
1424   }
1425 
1426   VM_Version::print_platform_virtualization_info(st);
1427 }
1428 
1429 void os::print_memory_info(outputStream* st) {
1430 
1431   st->print_cr("Memory:");
1432 
1433   st->print_cr("  Base page size (sysconf _SC_PAGESIZE):  %s",
1434     describe_pagesize(g_multipage_support.pagesize));
1435   st->print_cr("  Data page size (C-Heap, bss, etc):      %s",
1436     describe_pagesize(g_multipage_support.datapsize));
1437   st->print_cr("  Text page size:                         %s",
1438     describe_pagesize(g_multipage_support.textpsize));
1439   st->print_cr("  Thread stack page size (pthread):       %s",
1440     describe_pagesize(g_multipage_support.pthr_stack_pagesize));
1441   st->print_cr("  Default shared memory page size:        %s",
1442     describe_pagesize(g_multipage_support.shmpsize));
1443   st->print_cr("  Can use 64K pages dynamically with shared meory:  %s",
1444     (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
1445   st->print_cr("  Can use 16M pages dynamically with shared memory: %s",
1446     (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
1447   st->print_cr("  Multipage error: %d",
1448     g_multipage_support.error);
1449   st->cr();
1450   st->print_cr("  os::vm_page_size:       %s", describe_pagesize(os::vm_page_size()));
1451 
1452   // print out LDR_CNTRL because it affects the default page sizes
1453   const char* const ldr_cntrl = ::getenv("LDR_CNTRL");
1454   st->print_cr("  LDR_CNTRL=%s.", ldr_cntrl ? ldr_cntrl : "<unset>");
1455 
1456   // Print out EXTSHM because it is an unsupported setting.
1457   const char* const extshm = ::getenv("EXTSHM");
1458   st->print_cr("  EXTSHM=%s.", extshm ? extshm : "<unset>");
1459   if ( (strcmp(extshm, "on") == 0) || (strcmp(extshm, "ON") == 0) ) {
1460     st->print_cr("  *** Unsupported! Please remove EXTSHM from your environment! ***");
1461   }
1462 
1463   // Print out AIXTHREAD_GUARDPAGES because it affects the size of pthread stacks.
1464   const char* const aixthread_guardpages = ::getenv("AIXTHREAD_GUARDPAGES");
1465   st->print_cr("  AIXTHREAD_GUARDPAGES=%s.",
1466       aixthread_guardpages ? aixthread_guardpages : "<unset>");
1467   st->cr();
1468 
1469   os::Aix::meminfo_t mi;
1470   if (os::Aix::get_meminfo(&mi)) {
1471     if (os::Aix::on_aix()) {
1472       st->print_cr("physical total : " SIZE_FORMAT, mi.real_total);
1473       st->print_cr("physical free  : " SIZE_FORMAT, mi.real_free);
1474       st->print_cr("swap total     : " SIZE_FORMAT, mi.pgsp_total);
1475       st->print_cr("swap free      : " SIZE_FORMAT, mi.pgsp_free);
1476     } else {
1477       // PASE - Numbers are result of QWCRSSTS; they mean:
1478       // real_total: Sum of all system pools
1479       // real_free: always 0
1480       // pgsp_total: we take the size of the system ASP
1481       // pgsp_free: size of system ASP times percentage of system ASP unused
1482       st->print_cr("physical total     : " SIZE_FORMAT, mi.real_total);
1483       st->print_cr("system asp total   : " SIZE_FORMAT, mi.pgsp_total);
1484       st->print_cr("%% system asp used : %.2f",
1485         mi.pgsp_total ? (100.0f * (mi.pgsp_total - mi.pgsp_free) / mi.pgsp_total) : -1.0f);
1486     }
1487   }
1488   st->cr();
1489 
1490   // Print program break.
1491   st->print_cr("Program break at VM startup: " PTR_FORMAT ".", p2i(g_brk_at_startup));
1492   address brk_now = (address)::sbrk(0);
1493   if (brk_now != (address)-1) {
1494     st->print_cr("Program break now          : " PTR_FORMAT " (distance: " SIZE_FORMAT "k).",
1495                  p2i(brk_now), (size_t)((brk_now - g_brk_at_startup) / K));
1496   }
1497   st->print_cr("MaxExpectedDataSegmentSize    : " SIZE_FORMAT "k.", MaxExpectedDataSegmentSize / K);
1498   st->cr();
1499 
1500   // Print segments allocated with os::reserve_memory.
1501   st->print_cr("internal virtual memory regions used by vm:");
1502   vmembk_print_on(st);
1503 }
1504 
1505 // Get a string for the cpuinfo that is a summary of the cpu type
1506 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1507   // read _system_configuration.version
1508   switch (_system_configuration.version) {
1509   case PV_8:
1510     strncpy(buf, "Power PC 8", buflen);
1511     break;
1512   case PV_7:
1513     strncpy(buf, "Power PC 7", buflen);
1514     break;
1515   case PV_6_1:
1516     strncpy(buf, "Power PC 6 DD1.x", buflen);
1517     break;
1518   case PV_6:
1519     strncpy(buf, "Power PC 6", buflen);
1520     break;
1521   case PV_5:
1522     strncpy(buf, "Power PC 5", buflen);
1523     break;
1524   case PV_5_2:
1525     strncpy(buf, "Power PC 5_2", buflen);
1526     break;
1527   case PV_5_3:
1528     strncpy(buf, "Power PC 5_3", buflen);
1529     break;
1530   case PV_5_Compat:
1531     strncpy(buf, "PV_5_Compat", buflen);
1532     break;
1533   case PV_6_Compat:
1534     strncpy(buf, "PV_6_Compat", buflen);
1535     break;
1536   case PV_7_Compat:
1537     strncpy(buf, "PV_7_Compat", buflen);
1538     break;
1539   case PV_8_Compat:
1540     strncpy(buf, "PV_8_Compat", buflen);
1541     break;
1542   default:
1543     strncpy(buf, "unknown", buflen);
1544   }
1545 }
1546 
1547 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1548   // Nothing to do beyond of what os::print_cpu_info() does.
1549 }
1550 
1551 static void print_signal_handler(outputStream* st, int sig,
1552                                  char* buf, size_t buflen);
1553 
1554 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1555   st->print_cr("Signal Handlers:");
1556   print_signal_handler(st, SIGSEGV, buf, buflen);
1557   print_signal_handler(st, SIGBUS , buf, buflen);
1558   print_signal_handler(st, SIGFPE , buf, buflen);
1559   print_signal_handler(st, SIGPIPE, buf, buflen);
1560   print_signal_handler(st, SIGXFSZ, buf, buflen);
1561   print_signal_handler(st, SIGILL , buf, buflen);
1562   print_signal_handler(st, SR_signum, buf, buflen);
1563   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1564   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1565   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1566   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1567   print_signal_handler(st, SIGTRAP, buf, buflen);
1568   // We also want to know if someone else adds a SIGDANGER handler because
1569   // that will interfere with OOM killling.
1570   print_signal_handler(st, SIGDANGER, buf, buflen);
1571 }
1572 
1573 static char saved_jvm_path[MAXPATHLEN] = {0};
1574 
1575 // Find the full path to the current module, libjvm.so.
1576 void os::jvm_path(char *buf, jint buflen) {
1577   // Error checking.
1578   if (buflen < MAXPATHLEN) {
1579     assert(false, "must use a large-enough buffer");
1580     buf[0] = '\0';
1581     return;
1582   }
1583   // Lazy resolve the path to current module.
1584   if (saved_jvm_path[0] != 0) {
1585     strcpy(buf, saved_jvm_path);
1586     return;
1587   }
1588 
1589   Dl_info dlinfo;
1590   int ret = dladdr(CAST_FROM_FN_PTR(void *, os::jvm_path), &dlinfo);
1591   assert(ret != 0, "cannot locate libjvm");
1592   char* rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1593   assert(rp != NULL, "error in realpath(): maybe the 'path' argument is too long?");
1594 
1595   if (Arguments::sun_java_launcher_is_altjvm()) {
1596     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1597     // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
1598     // If "/jre/lib/" appears at the right place in the string, then
1599     // assume we are installed in a JDK and we're done. Otherwise, check
1600     // for a JAVA_HOME environment variable and fix up the path so it
1601     // looks like libjvm.so is installed there (append a fake suffix
1602     // hotspot/libjvm.so).
1603     const char *p = buf + strlen(buf) - 1;
1604     for (int count = 0; p > buf && count < 4; ++count) {
1605       for (--p; p > buf && *p != '/'; --p)
1606         /* empty */ ;
1607     }
1608 
1609     if (strncmp(p, "/jre/lib/", 9) != 0) {
1610       // Look for JAVA_HOME in the environment.
1611       char* java_home_var = ::getenv("JAVA_HOME");
1612       if (java_home_var != NULL && java_home_var[0] != 0) {
1613         char* jrelib_p;
1614         int len;
1615 
1616         // Check the current module name "libjvm.so".
1617         p = strrchr(buf, '/');
1618         if (p == NULL) {
1619           return;
1620         }
1621         assert(strstr(p, "/libjvm") == p, "invalid library name");
1622 
1623         rp = os::Posix::realpath(java_home_var, buf, buflen);
1624         if (rp == NULL) {
1625           return;
1626         }
1627 
1628         // determine if this is a legacy image or modules image
1629         // modules image doesn't have "jre" subdirectory
1630         len = strlen(buf);
1631         assert(len < buflen, "Ran out of buffer room");
1632         jrelib_p = buf + len;
1633         snprintf(jrelib_p, buflen-len, "/jre/lib");
1634         if (0 != access(buf, F_OK)) {
1635           snprintf(jrelib_p, buflen-len, "/lib");
1636         }
1637 
1638         if (0 == access(buf, F_OK)) {
1639           // Use current module name "libjvm.so"
1640           len = strlen(buf);
1641           snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
1642         } else {
1643           // Go back to path of .so
1644           rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1645           if (rp == NULL) {
1646             return;
1647           }
1648         }
1649       }
1650     }
1651   }
1652 
1653   strncpy(saved_jvm_path, buf, sizeof(saved_jvm_path));
1654   saved_jvm_path[sizeof(saved_jvm_path) - 1] = '\0';
1655 }
1656 
1657 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1658   // no prefix required, not even "_"
1659 }
1660 
1661 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1662   // no suffix required
1663 }
1664 
1665 ////////////////////////////////////////////////////////////////////////////////
1666 // sun.misc.Signal support
1667 
1668 static void
1669 UserHandler(int sig, void *siginfo, void *context) {
1670   // Ctrl-C is pressed during error reporting, likely because the error
1671   // handler fails to abort. Let VM die immediately.
1672   if (sig == SIGINT && VMError::is_error_reported()) {
1673     os::die();
1674   }
1675 
1676   os::signal_notify(sig);
1677 }
1678 
1679 void* os::user_handler() {
1680   return CAST_FROM_FN_PTR(void*, UserHandler);
1681 }
1682 
1683 extern "C" {
1684   typedef void (*sa_handler_t)(int);
1685   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1686 }
1687 
1688 void* os::signal(int signal_number, void* handler) {
1689   struct sigaction sigAct, oldSigAct;
1690 
1691   sigfillset(&(sigAct.sa_mask));
1692 
1693   // Do not block out synchronous signals in the signal handler.
1694   // Blocking synchronous signals only makes sense if you can really
1695   // be sure that those signals won't happen during signal handling,
1696   // when the blocking applies. Normal signal handlers are lean and
1697   // do not cause signals. But our signal handlers tend to be "risky"
1698   // - secondary SIGSEGV, SIGILL, SIGBUS' may and do happen.
1699   // On AIX, PASE there was a case where a SIGSEGV happened, followed
1700   // by a SIGILL, which was blocked due to the signal mask. The process
1701   // just hung forever. Better to crash from a secondary signal than to hang.
1702   sigdelset(&(sigAct.sa_mask), SIGSEGV);
1703   sigdelset(&(sigAct.sa_mask), SIGBUS);
1704   sigdelset(&(sigAct.sa_mask), SIGILL);
1705   sigdelset(&(sigAct.sa_mask), SIGFPE);
1706   sigdelset(&(sigAct.sa_mask), SIGTRAP);
1707 
1708   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1709 
1710   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1711 
1712   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1713     // -1 means registration failed
1714     return (void *)-1;
1715   }
1716 
1717   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1718 }
1719 
1720 void os::signal_raise(int signal_number) {
1721   ::raise(signal_number);
1722 }
1723 
1724 //
1725 // The following code is moved from os.cpp for making this
1726 // code platform specific, which it is by its very nature.
1727 //
1728 
1729 // Will be modified when max signal is changed to be dynamic
1730 int os::sigexitnum_pd() {
1731   return NSIG;
1732 }
1733 
1734 // a counter for each possible signal value
1735 static volatile jint pending_signals[NSIG+1] = { 0 };
1736 
1737 // Wrapper functions for: sem_init(), sem_post(), sem_wait()
1738 // On AIX, we use sem_init(), sem_post(), sem_wait()
1739 // On Pase, we need to use msem_lock() and msem_unlock(), because Posix Semaphores
1740 // do not seem to work at all on PASE (unimplemented, will cause SIGILL).
1741 // Note that just using msem_.. APIs for both PASE and AIX is not an option either, as
1742 // on AIX, msem_..() calls are suspected of causing problems.
1743 static sem_t sig_sem;
1744 static msemaphore* p_sig_msem = 0;
1745 
1746 static void local_sem_init() {
1747   if (os::Aix::on_aix()) {
1748     int rc = ::sem_init(&sig_sem, 0, 0);
1749     guarantee(rc != -1, "sem_init failed");
1750   } else {
1751     // Memory semaphores must live in shared mem.
1752     guarantee0(p_sig_msem == NULL);
1753     p_sig_msem = (msemaphore*)os::reserve_memory(sizeof(msemaphore), NULL);
1754     guarantee(p_sig_msem, "Cannot allocate memory for memory semaphore");
1755     guarantee(::msem_init(p_sig_msem, 0) == p_sig_msem, "msem_init failed");
1756   }
1757 }
1758 
1759 static void local_sem_post() {
1760   static bool warn_only_once = false;
1761   if (os::Aix::on_aix()) {
1762     int rc = ::sem_post(&sig_sem);
1763     if (rc == -1 && !warn_only_once) {
1764       trcVerbose("sem_post failed (errno = %d, %s)", errno, os::errno_name(errno));
1765       warn_only_once = true;
1766     }
1767   } else {
1768     guarantee0(p_sig_msem != NULL);
1769     int rc = ::msem_unlock(p_sig_msem, 0);
1770     if (rc == -1 && !warn_only_once) {
1771       trcVerbose("msem_unlock failed (errno = %d, %s)", errno, os::errno_name(errno));
1772       warn_only_once = true;
1773     }
1774   }
1775 }
1776 
1777 static void local_sem_wait() {
1778   static bool warn_only_once = false;
1779   if (os::Aix::on_aix()) {
1780     int rc = ::sem_wait(&sig_sem);
1781     if (rc == -1 && !warn_only_once) {
1782       trcVerbose("sem_wait failed (errno = %d, %s)", errno, os::errno_name(errno));
1783       warn_only_once = true;
1784     }
1785   } else {
1786     guarantee0(p_sig_msem != NULL); // must init before use
1787     int rc = ::msem_lock(p_sig_msem, 0);
1788     if (rc == -1 && !warn_only_once) {
1789       trcVerbose("msem_lock failed (errno = %d, %s)", errno, os::errno_name(errno));
1790       warn_only_once = true;
1791     }
1792   }
1793 }
1794 
1795 static void jdk_misc_signal_init() {
1796   // Initialize signal structures
1797   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
1798 
1799   // Initialize signal semaphore
1800   local_sem_init();
1801 }
1802 
1803 void os::signal_notify(int sig) {
1804   Atomic::inc(&pending_signals[sig]);
1805   local_sem_post();
1806 }
1807 
1808 static int check_pending_signals() {
1809   for (;;) {
1810     for (int i = 0; i < NSIG + 1; i++) {
1811       jint n = pending_signals[i];
1812       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
1813         return i;
1814       }
1815     }
1816     JavaThread *thread = JavaThread::current();
1817     ThreadBlockInVM tbivm(thread);
1818 
1819     bool threadIsSuspended;
1820     do {
1821       thread->set_suspend_equivalent();
1822       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1823 
1824       local_sem_wait();
1825 
1826       // were we externally suspended while we were waiting?
1827       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
1828       if (threadIsSuspended) {
1829         //
1830         // The semaphore has been incremented, but while we were waiting
1831         // another thread suspended us. We don't want to continue running
1832         // while suspended because that would surprise the thread that
1833         // suspended us.
1834         //
1835 
1836         local_sem_post();
1837 
1838         thread->java_suspend_self();
1839       }
1840     } while (threadIsSuspended);
1841   }
1842 }
1843 
1844 int os::signal_wait() {
1845   return check_pending_signals();
1846 }
1847 
1848 ////////////////////////////////////////////////////////////////////////////////
1849 // Virtual Memory
1850 
1851 // We need to keep small simple bookkeeping for os::reserve_memory and friends.
1852 
1853 #define VMEM_MAPPED  1
1854 #define VMEM_SHMATED 2
1855 
1856 struct vmembk_t {
1857   int type;         // 1 - mmap, 2 - shmat
1858   char* addr;
1859   size_t size;      // Real size, may be larger than usersize.
1860   size_t pagesize;  // page size of area
1861   vmembk_t* next;
1862 
1863   bool contains_addr(char* p) const {
1864     return p >= addr && p < (addr + size);
1865   }
1866 
1867   bool contains_range(char* p, size_t s) const {
1868     return contains_addr(p) && contains_addr(p + s - 1);
1869   }
1870 
1871   void print_on(outputStream* os) const {
1872     os->print("[" PTR_FORMAT " - " PTR_FORMAT "] (" UINTX_FORMAT
1873       " bytes, %d %s pages), %s",
1874       addr, addr + size - 1, size, size / pagesize, describe_pagesize(pagesize),
1875       (type == VMEM_SHMATED ? "shmat" : "mmap")
1876     );
1877   }
1878 
1879   // Check that range is a sub range of memory block (or equal to memory block);
1880   // also check that range is fully page aligned to the page size if the block.
1881   void assert_is_valid_subrange(char* p, size_t s) const {
1882     if (!contains_range(p, s)) {
1883       trcVerbose("[" PTR_FORMAT " - " PTR_FORMAT "] is not a sub "
1884               "range of [" PTR_FORMAT " - " PTR_FORMAT "].",
1885               p2i(p), p2i(p + s), p2i(addr), p2i(addr + size));
1886       guarantee0(false);
1887     }
1888     if (!is_aligned_to(p, pagesize) || !is_aligned_to(p + s, pagesize)) {
1889       trcVerbose("range [" PTR_FORMAT " - " PTR_FORMAT "] is not"
1890               " aligned to pagesize (%lu)", p2i(p), p2i(p + s), (unsigned long) pagesize);
1891       guarantee0(false);
1892     }
1893   }
1894 };
1895 
1896 static struct {
1897   vmembk_t* first;
1898   MiscUtils::CritSect cs;
1899 } vmem;
1900 
1901 static void vmembk_add(char* addr, size_t size, size_t pagesize, int type) {
1902   vmembk_t* p = (vmembk_t*) ::malloc(sizeof(vmembk_t));
1903   assert0(p);
1904   if (p) {
1905     MiscUtils::AutoCritSect lck(&vmem.cs);
1906     p->addr = addr; p->size = size;
1907     p->pagesize = pagesize;
1908     p->type = type;
1909     p->next = vmem.first;
1910     vmem.first = p;
1911   }
1912 }
1913 
1914 static vmembk_t* vmembk_find(char* addr) {
1915   MiscUtils::AutoCritSect lck(&vmem.cs);
1916   for (vmembk_t* p = vmem.first; p; p = p->next) {
1917     if (p->addr <= addr && (p->addr + p->size) > addr) {
1918       return p;
1919     }
1920   }
1921   return NULL;
1922 }
1923 
1924 static void vmembk_remove(vmembk_t* p0) {
1925   MiscUtils::AutoCritSect lck(&vmem.cs);
1926   assert0(p0);
1927   assert0(vmem.first); // List should not be empty.
1928   for (vmembk_t** pp = &(vmem.first); *pp; pp = &((*pp)->next)) {
1929     if (*pp == p0) {
1930       *pp = p0->next;
1931       ::free(p0);
1932       return;
1933     }
1934   }
1935   assert0(false); // Not found?
1936 }
1937 
1938 static void vmembk_print_on(outputStream* os) {
1939   MiscUtils::AutoCritSect lck(&vmem.cs);
1940   for (vmembk_t* vmi = vmem.first; vmi; vmi = vmi->next) {
1941     vmi->print_on(os);
1942     os->cr();
1943   }
1944 }
1945 
1946 // Reserve and attach a section of System V memory.
1947 // If <requested_addr> is not NULL, function will attempt to attach the memory at the given
1948 // address. Failing that, it will attach the memory anywhere.
1949 // If <requested_addr> is NULL, function will attach the memory anywhere.
1950 //
1951 // <alignment_hint> is being ignored by this function. It is very probable however that the
1952 // alignment requirements are met anyway, because shmat() attaches at 256M boundaries.
1953 // Should this be not enogh, we can put more work into it.
1954 static char* reserve_shmated_memory (
1955   size_t bytes,
1956   char* requested_addr,
1957   size_t alignment_hint) {
1958 
1959   trcVerbose("reserve_shmated_memory " UINTX_FORMAT " bytes, wishaddress "
1960     PTR_FORMAT ", alignment_hint " UINTX_FORMAT "...",
1961     bytes, p2i(requested_addr), alignment_hint);
1962 
1963   // Either give me wish address or wish alignment but not both.
1964   assert0(!(requested_addr != NULL && alignment_hint != 0));
1965 
1966   // We must prevent anyone from attaching too close to the
1967   // BRK because that may cause malloc OOM.
1968   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
1969     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
1970       "Will attach anywhere.", p2i(requested_addr));
1971     // Act like the OS refused to attach there.
1972     requested_addr = NULL;
1973   }
1974 
1975   // For old AS/400's (V5R4 and older) we should not even be here - System V shared memory is not
1976   // really supported (max size 4GB), so reserve_mmapped_memory should have been used instead.
1977   if (os::Aix::on_pase_V5R4_or_older()) {
1978     ShouldNotReachHere();
1979   }
1980 
1981   // Align size of shm up to 64K to avoid errors if we later try to change the page size.
1982   const size_t size = align_up(bytes, 64*K);
1983 
1984   // Reserve the shared segment.
1985   int shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | S_IRUSR | S_IWUSR);
1986   if (shmid == -1) {
1987     trcVerbose("shmget(.., " UINTX_FORMAT ", ..) failed (errno: %d).", size, errno);
1988     return NULL;
1989   }
1990 
1991   // Important note:
1992   // It is very important that we, upon leaving this function, do not leave a shm segment alive.
1993   // We must right after attaching it remove it from the system. System V shm segments are global and
1994   // survive the process.
1995   // So, from here on: Do not assert, do not return, until we have called shmctl(IPC_RMID) (A).
1996 
1997   struct shmid_ds shmbuf;
1998   memset(&shmbuf, 0, sizeof(shmbuf));
1999   shmbuf.shm_pagesize = 64*K;
2000   if (shmctl(shmid, SHM_PAGESIZE, &shmbuf) != 0) {
2001     trcVerbose("Failed to set page size (need " UINTX_FORMAT " 64K pages) - shmctl failed with %d.",
2002                size / (64*K), errno);
2003     // I want to know if this ever happens.
2004     assert(false, "failed to set page size for shmat");
2005   }
2006 
2007   // Now attach the shared segment.
2008   // Note that I attach with SHM_RND - which means that the requested address is rounded down, if
2009   // needed, to the next lowest segment boundary. Otherwise the attach would fail if the address
2010   // were not a segment boundary.
2011   char* const addr = (char*) shmat(shmid, requested_addr, SHM_RND);
2012   const int errno_shmat = errno;
2013 
2014   // (A) Right after shmat and before handing shmat errors delete the shm segment.
2015   if (::shmctl(shmid, IPC_RMID, NULL) == -1) {
2016     trcVerbose("shmctl(%u, IPC_RMID) failed (%d)\n", shmid, errno);
2017     assert(false, "failed to remove shared memory segment!");
2018   }
2019 
2020   // Handle shmat error. If we failed to attach, just return.
2021   if (addr == (char*)-1) {
2022     trcVerbose("Failed to attach segment at " PTR_FORMAT " (%d).", p2i(requested_addr), errno_shmat);
2023     return NULL;
2024   }
2025 
2026   // Just for info: query the real page size. In case setting the page size did not
2027   // work (see above), the system may have given us something other then 4K (LDR_CNTRL).
2028   const size_t real_pagesize = os::Aix::query_pagesize(addr);
2029   if (real_pagesize != shmbuf.shm_pagesize) {
2030     trcVerbose("pagesize is, surprisingly, " SIZE_FORMAT, real_pagesize);
2031   }
2032 
2033   if (addr) {
2034     trcVerbose("shm-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes, " UINTX_FORMAT " %s pages)",
2035       p2i(addr), p2i(addr + size - 1), size, size/real_pagesize, describe_pagesize(real_pagesize));
2036   } else {
2037     if (requested_addr != NULL) {
2038       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at with address " PTR_FORMAT ".", size, p2i(requested_addr));
2039     } else {
2040       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at any address.", size);
2041     }
2042   }
2043 
2044   // book-keeping
2045   vmembk_add(addr, size, real_pagesize, VMEM_SHMATED);
2046   assert0(is_aligned_to(addr, os::vm_page_size()));
2047 
2048   return addr;
2049 }
2050 
2051 static bool release_shmated_memory(char* addr, size_t size) {
2052 
2053   trcVerbose("release_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2054     p2i(addr), p2i(addr + size - 1));
2055 
2056   bool rc = false;
2057 
2058   // TODO: is there a way to verify shm size without doing bookkeeping?
2059   if (::shmdt(addr) != 0) {
2060     trcVerbose("error (%d).", errno);
2061   } else {
2062     trcVerbose("ok.");
2063     rc = true;
2064   }
2065   return rc;
2066 }
2067 
2068 static bool uncommit_shmated_memory(char* addr, size_t size) {
2069   trcVerbose("uncommit_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2070     p2i(addr), p2i(addr + size - 1));
2071 
2072   const bool rc = my_disclaim64(addr, size);
2073 
2074   if (!rc) {
2075     trcVerbose("my_disclaim64(" PTR_FORMAT ", " UINTX_FORMAT ") failed.\n", p2i(addr), size);
2076     return false;
2077   }
2078   return true;
2079 }
2080 
2081 ////////////////////////////////  mmap-based routines /////////////////////////////////
2082 
2083 // Reserve memory via mmap.
2084 // If <requested_addr> is given, an attempt is made to attach at the given address.
2085 // Failing that, memory is allocated at any address.
2086 // If <alignment_hint> is given and <requested_addr> is NULL, an attempt is made to
2087 // allocate at an address aligned with the given alignment. Failing that, memory
2088 // is aligned anywhere.
2089 static char* reserve_mmaped_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2090   trcVerbose("reserve_mmaped_memory " UINTX_FORMAT " bytes, wishaddress " PTR_FORMAT ", "
2091     "alignment_hint " UINTX_FORMAT "...",
2092     bytes, p2i(requested_addr), alignment_hint);
2093 
2094   // If a wish address is given, but not aligned to 4K page boundary, mmap will fail.
2095   if (requested_addr && !is_aligned_to(requested_addr, os::vm_page_size()) != 0) {
2096     trcVerbose("Wish address " PTR_FORMAT " not aligned to page boundary.", p2i(requested_addr));
2097     return NULL;
2098   }
2099 
2100   // We must prevent anyone from attaching too close to the
2101   // BRK because that may cause malloc OOM.
2102   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
2103     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
2104       "Will attach anywhere.", p2i(requested_addr));
2105     // Act like the OS refused to attach there.
2106     requested_addr = NULL;
2107   }
2108 
2109   // Specify one or the other but not both.
2110   assert0(!(requested_addr != NULL && alignment_hint > 0));
2111 
2112   // In 64K mode, we claim the global page size (os::vm_page_size())
2113   // is 64K. This is one of the few points where that illusion may
2114   // break, because mmap() will always return memory aligned to 4K. So
2115   // we must ensure we only ever return memory aligned to 64k.
2116   if (alignment_hint) {
2117     alignment_hint = lcm(alignment_hint, os::vm_page_size());
2118   } else {
2119     alignment_hint = os::vm_page_size();
2120   }
2121 
2122   // Size shall always be a multiple of os::vm_page_size (esp. in 64K mode).
2123   const size_t size = align_up(bytes, os::vm_page_size());
2124 
2125   // alignment: Allocate memory large enough to include an aligned range of the right size and
2126   // cut off the leading and trailing waste pages.
2127   assert0(alignment_hint != 0 && is_aligned_to(alignment_hint, os::vm_page_size())); // see above
2128   const size_t extra_size = size + alignment_hint;
2129 
2130   // Note: MAP_SHARED (instead of MAP_PRIVATE) needed to be able to
2131   // later use msync(MS_INVALIDATE) (see os::uncommit_memory).
2132   int flags = MAP_ANONYMOUS | MAP_SHARED;
2133 
2134   // MAP_FIXED is needed to enforce requested_addr - manpage is vague about what
2135   // it means if wishaddress is given but MAP_FIXED is not set.
2136   //
2137   // Important! Behaviour differs depending on whether SPEC1170 mode is active or not.
2138   // SPEC1170 mode active: behaviour like POSIX, MAP_FIXED will clobber existing mappings.
2139   // SPEC1170 mode not active: behaviour, unlike POSIX, is that no existing mappings will
2140   // get clobbered.
2141   if (requested_addr != NULL) {
2142     if (!os::Aix::xpg_sus_mode()) {  // not SPEC1170 Behaviour
2143       flags |= MAP_FIXED;
2144     }
2145   }
2146 
2147   char* addr = (char*)::mmap(requested_addr, extra_size,
2148       PROT_READ|PROT_WRITE|PROT_EXEC, flags, -1, 0);
2149 
2150   if (addr == MAP_FAILED) {
2151     trcVerbose("mmap(" PTR_FORMAT ", " UINTX_FORMAT ", ..) failed (%d)", p2i(requested_addr), size, errno);
2152     return NULL;
2153   }
2154 
2155   // Handle alignment.
2156   char* const addr_aligned = align_up(addr, alignment_hint);
2157   const size_t waste_pre = addr_aligned - addr;
2158   char* const addr_aligned_end = addr_aligned + size;
2159   const size_t waste_post = extra_size - waste_pre - size;
2160   if (waste_pre > 0) {
2161     ::munmap(addr, waste_pre);
2162   }
2163   if (waste_post > 0) {
2164     ::munmap(addr_aligned_end, waste_post);
2165   }
2166   addr = addr_aligned;
2167 
2168   if (addr) {
2169     trcVerbose("mmap-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes)",
2170       p2i(addr), p2i(addr + bytes), bytes);
2171   } else {
2172     if (requested_addr != NULL) {
2173       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at wish address " PTR_FORMAT ".", bytes, p2i(requested_addr));
2174     } else {
2175       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at any address.", bytes);
2176     }
2177   }
2178 
2179   // bookkeeping
2180   vmembk_add(addr, size, 4*K, VMEM_MAPPED);
2181 
2182   // Test alignment, see above.
2183   assert0(is_aligned_to(addr, os::vm_page_size()));
2184 
2185   return addr;
2186 }
2187 
2188 static bool release_mmaped_memory(char* addr, size_t size) {
2189   assert0(is_aligned_to(addr, os::vm_page_size()));
2190   assert0(is_aligned_to(size, os::vm_page_size()));
2191 
2192   trcVerbose("release_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2193     p2i(addr), p2i(addr + size - 1));
2194   bool rc = false;
2195 
2196   if (::munmap(addr, size) != 0) {
2197     trcVerbose("failed (%d)\n", errno);
2198     rc = false;
2199   } else {
2200     trcVerbose("ok.");
2201     rc = true;
2202   }
2203 
2204   return rc;
2205 }
2206 
2207 static bool uncommit_mmaped_memory(char* addr, size_t size) {
2208 
2209   assert0(is_aligned_to(addr, os::vm_page_size()));
2210   assert0(is_aligned_to(size, os::vm_page_size()));
2211 
2212   trcVerbose("uncommit_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2213     p2i(addr), p2i(addr + size - 1));
2214   bool rc = false;
2215 
2216   // Uncommit mmap memory with msync MS_INVALIDATE.
2217   if (::msync(addr, size, MS_INVALIDATE) != 0) {
2218     trcVerbose("failed (%d)\n", errno);
2219     rc = false;
2220   } else {
2221     trcVerbose("ok.");
2222     rc = true;
2223   }
2224 
2225   return rc;
2226 }
2227 
2228 int os::vm_page_size() {
2229   // Seems redundant as all get out.
2230   assert(os::Aix::page_size() != -1, "must call os::init");
2231   return os::Aix::page_size();
2232 }
2233 
2234 // Aix allocates memory by pages.
2235 int os::vm_allocation_granularity() {
2236   assert(os::Aix::page_size() != -1, "must call os::init");
2237   return os::Aix::page_size();
2238 }
2239 
2240 #ifdef PRODUCT
2241 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2242                                     int err) {
2243   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2244           ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2245           os::errno_name(err), err);
2246 }
2247 #endif
2248 
2249 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2250                                   const char* mesg) {
2251   assert(mesg != NULL, "mesg must be specified");
2252   if (!pd_commit_memory(addr, size, exec)) {
2253     // Add extra info in product mode for vm_exit_out_of_memory():
2254     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2255     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2256   }
2257 }
2258 
2259 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2260 
2261   assert(is_aligned_to(addr, os::vm_page_size()),
2262     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2263     p2i(addr), os::vm_page_size());
2264   assert(is_aligned_to(size, os::vm_page_size()),
2265     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2266     size, os::vm_page_size());
2267 
2268   vmembk_t* const vmi = vmembk_find(addr);
2269   guarantee0(vmi);
2270   vmi->assert_is_valid_subrange(addr, size);
2271 
2272   trcVerbose("commit_memory [" PTR_FORMAT " - " PTR_FORMAT "].", p2i(addr), p2i(addr + size - 1));
2273 
2274   if (UseExplicitCommit) {
2275     // AIX commits memory on touch. So, touch all pages to be committed.
2276     for (char* p = addr; p < (addr + size); p += 4*K) {
2277       *p = '\0';
2278     }
2279   }
2280 
2281   return true;
2282 }
2283 
2284 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, bool exec) {
2285   return pd_commit_memory(addr, size, exec);
2286 }
2287 
2288 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2289                                   size_t alignment_hint, bool exec,
2290                                   const char* mesg) {
2291   // Alignment_hint is ignored on this OS.
2292   pd_commit_memory_or_exit(addr, size, exec, mesg);
2293 }
2294 
2295 bool os::pd_uncommit_memory(char* addr, size_t size) {
2296   assert(is_aligned_to(addr, os::vm_page_size()),
2297     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2298     p2i(addr), os::vm_page_size());
2299   assert(is_aligned_to(size, os::vm_page_size()),
2300     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2301     size, os::vm_page_size());
2302 
2303   // Dynamically do different things for mmap/shmat.
2304   const vmembk_t* const vmi = vmembk_find(addr);
2305   guarantee0(vmi);
2306   vmi->assert_is_valid_subrange(addr, size);
2307 
2308   if (vmi->type == VMEM_SHMATED) {
2309     return uncommit_shmated_memory(addr, size);
2310   } else {
2311     return uncommit_mmaped_memory(addr, size);
2312   }
2313 }
2314 
2315 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2316   // Do not call this; no need to commit stack pages on AIX.
2317   ShouldNotReachHere();
2318   return true;
2319 }
2320 
2321 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2322   // Do not call this; no need to commit stack pages on AIX.
2323   ShouldNotReachHere();
2324   return true;
2325 }
2326 
2327 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2328 }
2329 
2330 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2331 }
2332 
2333 void os::numa_make_global(char *addr, size_t bytes) {
2334 }
2335 
2336 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2337 }
2338 
2339 bool os::numa_topology_changed() {
2340   return false;
2341 }
2342 
2343 size_t os::numa_get_groups_num() {
2344   return 1;
2345 }
2346 
2347 int os::numa_get_group_id() {
2348   return 0;
2349 }
2350 
2351 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2352   if (size > 0) {
2353     ids[0] = 0;
2354     return 1;
2355   }
2356   return 0;
2357 }
2358 
2359 bool os::get_page_info(char *start, page_info* info) {
2360   return false;
2361 }
2362 
2363 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2364   return end;
2365 }
2366 
2367 // Reserves and attaches a shared memory segment.
2368 // Will assert if a wish address is given and could not be obtained.
2369 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2370 
2371   // All other Unices do a mmap(MAP_FIXED) if the addr is given,
2372   // thereby clobbering old mappings at that place. That is probably
2373   // not intended, never used and almost certainly an error were it
2374   // ever be used this way (to try attaching at a specified address
2375   // without clobbering old mappings an alternate API exists,
2376   // os::attempt_reserve_memory_at()).
2377   // Instead of mimicking the dangerous coding of the other platforms, here I
2378   // just ignore the request address (release) or assert(debug).
2379   assert0(requested_addr == NULL);
2380 
2381   // Always round to os::vm_page_size(), which may be larger than 4K.
2382   bytes = align_up(bytes, os::vm_page_size());
2383   const size_t alignment_hint0 =
2384     alignment_hint ? align_up(alignment_hint, os::vm_page_size()) : 0;
2385 
2386   // In 4K mode always use mmap.
2387   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2388   if (os::vm_page_size() == 4*K) {
2389     return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2390   } else {
2391     if (bytes >= Use64KPagesThreshold) {
2392       return reserve_shmated_memory(bytes, requested_addr, alignment_hint);
2393     } else {
2394       return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2395     }
2396   }
2397 }
2398 
2399 bool os::pd_release_memory(char* addr, size_t size) {
2400 
2401   // Dynamically do different things for mmap/shmat.
2402   vmembk_t* const vmi = vmembk_find(addr);
2403   guarantee0(vmi);
2404 
2405   // Always round to os::vm_page_size(), which may be larger than 4K.
2406   size = align_up(size, os::vm_page_size());
2407   addr = align_up(addr, os::vm_page_size());
2408 
2409   bool rc = false;
2410   bool remove_bookkeeping = false;
2411   if (vmi->type == VMEM_SHMATED) {
2412     // For shmatted memory, we do:
2413     // - If user wants to release the whole range, release the memory (shmdt).
2414     // - If user only wants to release a partial range, uncommit (disclaim) that
2415     //   range. That way, at least, we do not use memory anymore (bust still page
2416     //   table space).
2417     vmi->assert_is_valid_subrange(addr, size);
2418     if (addr == vmi->addr && size == vmi->size) {
2419       rc = release_shmated_memory(addr, size);
2420       remove_bookkeeping = true;
2421     } else {
2422       rc = uncommit_shmated_memory(addr, size);
2423     }
2424   } else {
2425     // User may unmap partial regions but region has to be fully contained.
2426 #ifdef ASSERT
2427     vmi->assert_is_valid_subrange(addr, size);
2428 #endif
2429     rc = release_mmaped_memory(addr, size);
2430     remove_bookkeeping = true;
2431   }
2432 
2433   // update bookkeeping
2434   if (rc && remove_bookkeeping) {
2435     vmembk_remove(vmi);
2436   }
2437 
2438   return rc;
2439 }
2440 
2441 static bool checked_mprotect(char* addr, size_t size, int prot) {
2442 
2443   // Little problem here: if SPEC1170 behaviour is off, mprotect() on AIX will
2444   // not tell me if protection failed when trying to protect an un-protectable range.
2445   //
2446   // This means if the memory was allocated using shmget/shmat, protection wont work
2447   // but mprotect will still return 0:
2448   //
2449   // See http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/mprotect.htm
2450 
2451   Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(addr), p2i(addr+size), prot);
2452   bool rc = ::mprotect(addr, size, prot) == 0 ? true : false;
2453 
2454   if (!rc) {
2455     const char* const s_errno = os::errno_name(errno);
2456     warning("mprotect(" PTR_FORMAT "-" PTR_FORMAT ", 0x%X) failed (%s).", addr, addr + size, prot, s_errno);
2457     return false;
2458   }
2459 
2460   // mprotect success check
2461   //
2462   // Mprotect said it changed the protection but can I believe it?
2463   //
2464   // To be sure I need to check the protection afterwards. Try to
2465   // read from protected memory and check whether that causes a segfault.
2466   //
2467   if (!os::Aix::xpg_sus_mode()) {
2468 
2469     if (CanUseSafeFetch32()) {
2470 
2471       const bool read_protected =
2472         (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2473          SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2474 
2475       if (prot & PROT_READ) {
2476         rc = !read_protected;
2477       } else {
2478         rc = read_protected;
2479       }
2480 
2481       if (!rc) {
2482         if (os::Aix::on_pase()) {
2483           // There is an issue on older PASE systems where mprotect() will return success but the
2484           // memory will not be protected.
2485           // This has nothing to do with the problem of using mproect() on SPEC1170 incompatible
2486           // machines; we only see it rarely, when using mprotect() to protect the guard page of
2487           // a stack. It is an OS error.
2488           //
2489           // A valid strategy is just to try again. This usually works. :-/
2490 
2491           ::usleep(1000);
2492           Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(addr), p2i(addr+size), prot);
2493           if (::mprotect(addr, size, prot) == 0) {
2494             const bool read_protected_2 =
2495               (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2496               SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2497             rc = true;
2498           }
2499         }
2500       }
2501     }
2502   }
2503 
2504   assert(rc == true, "mprotect failed.");
2505 
2506   return rc;
2507 }
2508 
2509 // Set protections specified
2510 bool os::protect_memory(char* addr, size_t size, ProtType prot, bool is_committed) {
2511   unsigned int p = 0;
2512   switch (prot) {
2513   case MEM_PROT_NONE: p = PROT_NONE; break;
2514   case MEM_PROT_READ: p = PROT_READ; break;
2515   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2516   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2517   default:
2518     ShouldNotReachHere();
2519   }
2520   // is_committed is unused.
2521   return checked_mprotect(addr, size, p);
2522 }
2523 
2524 bool os::guard_memory(char* addr, size_t size) {
2525   return checked_mprotect(addr, size, PROT_NONE);
2526 }
2527 
2528 bool os::unguard_memory(char* addr, size_t size) {
2529   return checked_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
2530 }
2531 
2532 // Large page support
2533 
2534 static size_t _large_page_size = 0;
2535 
2536 // Enable large page support if OS allows that.
2537 void os::large_page_init() {
2538   return; // Nothing to do. See query_multipage_support and friends.
2539 }
2540 
2541 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2542   // reserve_memory_special() is used to allocate large paged memory. On AIX, we implement
2543   // 64k paged memory reservation using the normal memory allocation paths (os::reserve_memory()),
2544   // so this is not needed.
2545   assert(false, "should not be called on AIX");
2546   return NULL;
2547 }
2548 
2549 bool os::release_memory_special(char* base, size_t bytes) {
2550   // Detaching the SHM segment will also delete it, see reserve_memory_special().
2551   Unimplemented();
2552   return false;
2553 }
2554 
2555 size_t os::large_page_size() {
2556   return _large_page_size;
2557 }
2558 
2559 bool os::can_commit_large_page_memory() {
2560   // Does not matter, we do not support huge pages.
2561   return false;
2562 }
2563 
2564 bool os::can_execute_large_page_memory() {
2565   // Does not matter, we do not support huge pages.
2566   return false;
2567 }
2568 
2569 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
2570   assert(file_desc >= 0, "file_desc is not valid");
2571   char* result = NULL;
2572 
2573   // Always round to os::vm_page_size(), which may be larger than 4K.
2574   bytes = align_up(bytes, os::vm_page_size());
2575   result = reserve_mmaped_memory(bytes, requested_addr, 0);
2576 
2577   if (result != NULL) {
2578     if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
2579       vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
2580     }
2581   }
2582   return result;
2583 }
2584 
2585 // Reserve memory at an arbitrary address, only if that area is
2586 // available (and not reserved for something else).
2587 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2588   char* addr = NULL;
2589 
2590   // Always round to os::vm_page_size(), which may be larger than 4K.
2591   bytes = align_up(bytes, os::vm_page_size());
2592 
2593   // In 4K mode always use mmap.
2594   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2595   if (os::vm_page_size() == 4*K) {
2596     return reserve_mmaped_memory(bytes, requested_addr, 0);
2597   } else {
2598     if (bytes >= Use64KPagesThreshold) {
2599       return reserve_shmated_memory(bytes, requested_addr, 0);
2600     } else {
2601       return reserve_mmaped_memory(bytes, requested_addr, 0);
2602     }
2603   }
2604 
2605   return addr;
2606 }
2607 
2608 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2609 void os::infinite_sleep() {
2610   while (true) {    // sleep forever ...
2611     ::sleep(100);   // ... 100 seconds at a time
2612   }
2613 }
2614 
2615 // Used to convert frequent JVM_Yield() to nops
2616 bool os::dont_yield() {
2617   return DontYieldALot;
2618 }
2619 
2620 void os::naked_yield() {
2621   sched_yield();
2622 }
2623 
2624 ////////////////////////////////////////////////////////////////////////////////
2625 // thread priority support
2626 
2627 // From AIX manpage to pthread_setschedparam
2628 // (see: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?
2629 //    topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_setschedparam.htm):
2630 //
2631 // "If schedpolicy is SCHED_OTHER, then sched_priority must be in the
2632 // range from 40 to 80, where 40 is the least favored priority and 80
2633 // is the most favored."
2634 //
2635 // (Actually, I doubt this even has an impact on AIX, as we do kernel
2636 // scheduling there; however, this still leaves iSeries.)
2637 //
2638 // We use the same values for AIX and PASE.
2639 int os::java_to_os_priority[CriticalPriority + 1] = {
2640   54,             // 0 Entry should never be used
2641 
2642   55,             // 1 MinPriority
2643   55,             // 2
2644   56,             // 3
2645 
2646   56,             // 4
2647   57,             // 5 NormPriority
2648   57,             // 6
2649 
2650   58,             // 7
2651   58,             // 8
2652   59,             // 9 NearMaxPriority
2653 
2654   60,             // 10 MaxPriority
2655 
2656   60              // 11 CriticalPriority
2657 };
2658 
2659 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2660   if (!UseThreadPriorities) return OS_OK;
2661   pthread_t thr = thread->osthread()->pthread_id();
2662   int policy = SCHED_OTHER;
2663   struct sched_param param;
2664   param.sched_priority = newpri;
2665   int ret = pthread_setschedparam(thr, policy, &param);
2666 
2667   if (ret != 0) {
2668     trcVerbose("Could not change priority for thread %d to %d (error %d, %s)",
2669         (int)thr, newpri, ret, os::errno_name(ret));
2670   }
2671   return (ret == 0) ? OS_OK : OS_ERR;
2672 }
2673 
2674 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2675   if (!UseThreadPriorities) {
2676     *priority_ptr = java_to_os_priority[NormPriority];
2677     return OS_OK;
2678   }
2679   pthread_t thr = thread->osthread()->pthread_id();
2680   int policy = SCHED_OTHER;
2681   struct sched_param param;
2682   int ret = pthread_getschedparam(thr, &policy, &param);
2683   *priority_ptr = param.sched_priority;
2684 
2685   return (ret == 0) ? OS_OK : OS_ERR;
2686 }
2687 
2688 ////////////////////////////////////////////////////////////////////////////////
2689 // suspend/resume support
2690 
2691 //  The low-level signal-based suspend/resume support is a remnant from the
2692 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2693 //  within hotspot. Currently used by JFR's OSThreadSampler
2694 //
2695 //  The remaining code is greatly simplified from the more general suspension
2696 //  code that used to be used.
2697 //
2698 //  The protocol is quite simple:
2699 //  - suspend:
2700 //      - sends a signal to the target thread
2701 //      - polls the suspend state of the osthread using a yield loop
2702 //      - target thread signal handler (SR_handler) sets suspend state
2703 //        and blocks in sigsuspend until continued
2704 //  - resume:
2705 //      - sets target osthread state to continue
2706 //      - sends signal to end the sigsuspend loop in the SR_handler
2707 //
2708 //  Note that the SR_lock plays no role in this suspend/resume protocol,
2709 //  but is checked for NULL in SR_handler as a thread termination indicator.
2710 //  The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
2711 //
2712 //  Note that resume_clear_context() and suspend_save_context() are needed
2713 //  by SR_handler(), so that fetch_frame_from_ucontext() works,
2714 //  which in part is used by:
2715 //    - Forte Analyzer: AsyncGetCallTrace()
2716 //    - StackBanging: get_frame_at_stack_banging_point()
2717 
2718 static void resume_clear_context(OSThread *osthread) {
2719   osthread->set_ucontext(NULL);
2720   osthread->set_siginfo(NULL);
2721 }
2722 
2723 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2724   osthread->set_ucontext(context);
2725   osthread->set_siginfo(siginfo);
2726 }
2727 
2728 //
2729 // Handler function invoked when a thread's execution is suspended or
2730 // resumed. We have to be careful that only async-safe functions are
2731 // called here (Note: most pthread functions are not async safe and
2732 // should be avoided.)
2733 //
2734 // Note: sigwait() is a more natural fit than sigsuspend() from an
2735 // interface point of view, but sigwait() prevents the signal hander
2736 // from being run. libpthread would get very confused by not having
2737 // its signal handlers run and prevents sigwait()'s use with the
2738 // mutex granting granting signal.
2739 //
2740 // Currently only ever called on the VMThread and JavaThreads (PC sampling).
2741 //
2742 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2743   // Save and restore errno to avoid confusing native code with EINTR
2744   // after sigsuspend.
2745   int old_errno = errno;
2746 
2747   Thread* thread = Thread::current_or_null_safe();
2748   assert(thread != NULL, "Missing current thread in SR_handler");
2749 
2750   // On some systems we have seen signal delivery get "stuck" until the signal
2751   // mask is changed as part of thread termination. Check that the current thread
2752   // has not already terminated (via SR_lock()) - else the following assertion
2753   // will fail because the thread is no longer a JavaThread as the ~JavaThread
2754   // destructor has completed.
2755 
2756   if (thread->SR_lock() == NULL) {
2757     return;
2758   }
2759 
2760   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2761 
2762   OSThread* osthread = thread->osthread();
2763 
2764   os::SuspendResume::State current = osthread->sr.state();
2765   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2766     suspend_save_context(osthread, siginfo, context);
2767 
2768     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2769     os::SuspendResume::State state = osthread->sr.suspended();
2770     if (state == os::SuspendResume::SR_SUSPENDED) {
2771       sigset_t suspend_set;  // signals for sigsuspend()
2772 
2773       // get current set of blocked signals and unblock resume signal
2774       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2775       sigdelset(&suspend_set, SR_signum);
2776 
2777       // wait here until we are resumed
2778       while (1) {
2779         sigsuspend(&suspend_set);
2780 
2781         os::SuspendResume::State result = osthread->sr.running();
2782         if (result == os::SuspendResume::SR_RUNNING) {
2783           break;
2784         }
2785       }
2786 
2787     } else if (state == os::SuspendResume::SR_RUNNING) {
2788       // request was cancelled, continue
2789     } else {
2790       ShouldNotReachHere();
2791     }
2792 
2793     resume_clear_context(osthread);
2794   } else if (current == os::SuspendResume::SR_RUNNING) {
2795     // request was cancelled, continue
2796   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2797     // ignore
2798   } else {
2799     ShouldNotReachHere();
2800   }
2801 
2802   errno = old_errno;
2803 }
2804 
2805 static int SR_initialize() {
2806   struct sigaction act;
2807   char *s;
2808   // Get signal number to use for suspend/resume
2809   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2810     int sig = ::strtol(s, 0, 10);
2811     if (sig > MAX2(SIGSEGV, SIGBUS) &&  // See 4355769.
2812         sig < NSIG) {                   // Must be legal signal and fit into sigflags[].
2813       SR_signum = sig;
2814     } else {
2815       warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
2816               sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
2817     }
2818   }
2819 
2820   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2821         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2822 
2823   sigemptyset(&SR_sigset);
2824   sigaddset(&SR_sigset, SR_signum);
2825 
2826   // Set up signal handler for suspend/resume.
2827   act.sa_flags = SA_RESTART|SA_SIGINFO;
2828   act.sa_handler = (void (*)(int)) SR_handler;
2829 
2830   // SR_signum is blocked by default.
2831   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2832 
2833   if (sigaction(SR_signum, &act, 0) == -1) {
2834     return -1;
2835   }
2836 
2837   // Save signal flag
2838   os::Aix::set_our_sigflags(SR_signum, act.sa_flags);
2839   return 0;
2840 }
2841 
2842 static int SR_finalize() {
2843   return 0;
2844 }
2845 
2846 static int sr_notify(OSThread* osthread) {
2847   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2848   assert_status(status == 0, status, "pthread_kill");
2849   return status;
2850 }
2851 
2852 // "Randomly" selected value for how long we want to spin
2853 // before bailing out on suspending a thread, also how often
2854 // we send a signal to a thread we want to resume
2855 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2856 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2857 
2858 // returns true on success and false on error - really an error is fatal
2859 // but this seems the normal response to library errors
2860 static bool do_suspend(OSThread* osthread) {
2861   assert(osthread->sr.is_running(), "thread should be running");
2862   // mark as suspended and send signal
2863 
2864   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2865     // failed to switch, state wasn't running?
2866     ShouldNotReachHere();
2867     return false;
2868   }
2869 
2870   if (sr_notify(osthread) != 0) {
2871     // try to cancel, switch to running
2872 
2873     os::SuspendResume::State result = osthread->sr.cancel_suspend();
2874     if (result == os::SuspendResume::SR_RUNNING) {
2875       // cancelled
2876       return false;
2877     } else if (result == os::SuspendResume::SR_SUSPENDED) {
2878       // somehow managed to suspend
2879       return true;
2880     } else {
2881       ShouldNotReachHere();
2882       return false;
2883     }
2884   }
2885 
2886   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2887 
2888   for (int n = 0; !osthread->sr.is_suspended(); n++) {
2889     for (int i = 0; i < RANDOMLY_LARGE_INTEGER2 && !osthread->sr.is_suspended(); i++) {
2890       os::naked_yield();
2891     }
2892 
2893     // timeout, try to cancel the request
2894     if (n >= RANDOMLY_LARGE_INTEGER) {
2895       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2896       if (cancelled == os::SuspendResume::SR_RUNNING) {
2897         return false;
2898       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2899         return true;
2900       } else {
2901         ShouldNotReachHere();
2902         return false;
2903       }
2904     }
2905   }
2906 
2907   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2908   return true;
2909 }
2910 
2911 static void do_resume(OSThread* osthread) {
2912   //assert(osthread->sr.is_suspended(), "thread should be suspended");
2913 
2914   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2915     // failed to switch to WAKEUP_REQUEST
2916     ShouldNotReachHere();
2917     return;
2918   }
2919 
2920   while (!osthread->sr.is_running()) {
2921     if (sr_notify(osthread) == 0) {
2922       for (int n = 0; n < RANDOMLY_LARGE_INTEGER && !osthread->sr.is_running(); n++) {
2923         for (int i = 0; i < 100 && !osthread->sr.is_running(); i++) {
2924           os::naked_yield();
2925         }
2926       }
2927     } else {
2928       ShouldNotReachHere();
2929     }
2930   }
2931 
2932   guarantee(osthread->sr.is_running(), "Must be running!");
2933 }
2934 
2935 ///////////////////////////////////////////////////////////////////////////////////
2936 // signal handling (except suspend/resume)
2937 
2938 // This routine may be used by user applications as a "hook" to catch signals.
2939 // The user-defined signal handler must pass unrecognized signals to this
2940 // routine, and if it returns true (non-zero), then the signal handler must
2941 // return immediately. If the flag "abort_if_unrecognized" is true, then this
2942 // routine will never retun false (zero), but instead will execute a VM panic
2943 // routine kill the process.
2944 //
2945 // If this routine returns false, it is OK to call it again. This allows
2946 // the user-defined signal handler to perform checks either before or after
2947 // the VM performs its own checks. Naturally, the user code would be making
2948 // a serious error if it tried to handle an exception (such as a null check
2949 // or breakpoint) that the VM was generating for its own correct operation.
2950 //
2951 // This routine may recognize any of the following kinds of signals:
2952 //   SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2953 // It should be consulted by handlers for any of those signals.
2954 //
2955 // The caller of this routine must pass in the three arguments supplied
2956 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2957 // field of the structure passed to sigaction(). This routine assumes that
2958 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2959 //
2960 // Note that the VM will print warnings if it detects conflicting signal
2961 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2962 //
2963 extern "C" JNIEXPORT int
2964 JVM_handle_aix_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized);
2965 
2966 // Set thread signal mask (for some reason on AIX sigthreadmask() seems
2967 // to be the thing to call; documentation is not terribly clear about whether
2968 // pthread_sigmask also works, and if it does, whether it does the same.
2969 bool set_thread_signal_mask(int how, const sigset_t* set, sigset_t* oset) {
2970   const int rc = ::pthread_sigmask(how, set, oset);
2971   // return value semantics differ slightly for error case:
2972   // pthread_sigmask returns error number, sigthreadmask -1 and sets global errno
2973   // (so, pthread_sigmask is more theadsafe for error handling)
2974   // But success is always 0.
2975   return rc == 0 ? true : false;
2976 }
2977 
2978 // Function to unblock all signals which are, according
2979 // to POSIX, typical program error signals. If they happen while being blocked,
2980 // they typically will bring down the process immediately.
2981 bool unblock_program_error_signals() {
2982   sigset_t set;
2983   ::sigemptyset(&set);
2984   ::sigaddset(&set, SIGILL);
2985   ::sigaddset(&set, SIGBUS);
2986   ::sigaddset(&set, SIGFPE);
2987   ::sigaddset(&set, SIGSEGV);
2988   return set_thread_signal_mask(SIG_UNBLOCK, &set, NULL);
2989 }
2990 
2991 // Renamed from 'signalHandler' to avoid collision with other shared libs.
2992 static void javaSignalHandler(int sig, siginfo_t* info, void* uc) {
2993   assert(info != NULL && uc != NULL, "it must be old kernel");
2994 
2995   // Never leave program error signals blocked;
2996   // on all our platforms they would bring down the process immediately when
2997   // getting raised while being blocked.
2998   unblock_program_error_signals();
2999 
3000   int orig_errno = errno;  // Preserve errno value over signal handler.
3001   JVM_handle_aix_signal(sig, info, uc, true);
3002   errno = orig_errno;
3003 }
3004 
3005 // This boolean allows users to forward their own non-matching signals
3006 // to JVM_handle_aix_signal, harmlessly.
3007 bool os::Aix::signal_handlers_are_installed = false;
3008 
3009 // For signal-chaining
3010 bool os::Aix::libjsig_is_loaded = false;
3011 typedef struct sigaction *(*get_signal_t)(int);
3012 get_signal_t os::Aix::get_signal_action = NULL;
3013 
3014 struct sigaction* os::Aix::get_chained_signal_action(int sig) {
3015   struct sigaction *actp = NULL;
3016 
3017   if (libjsig_is_loaded) {
3018     // Retrieve the old signal handler from libjsig
3019     actp = (*get_signal_action)(sig);
3020   }
3021   if (actp == NULL) {
3022     // Retrieve the preinstalled signal handler from jvm
3023     actp = os::Posix::get_preinstalled_handler(sig);
3024   }
3025 
3026   return actp;
3027 }
3028 
3029 static bool call_chained_handler(struct sigaction *actp, int sig,
3030                                  siginfo_t *siginfo, void *context) {
3031   // Call the old signal handler
3032   if (actp->sa_handler == SIG_DFL) {
3033     // It's more reasonable to let jvm treat it as an unexpected exception
3034     // instead of taking the default action.
3035     return false;
3036   } else if (actp->sa_handler != SIG_IGN) {
3037     if ((actp->sa_flags & SA_NODEFER) == 0) {
3038       // automaticlly block the signal
3039       sigaddset(&(actp->sa_mask), sig);
3040     }
3041 
3042     sa_handler_t hand = NULL;
3043     sa_sigaction_t sa = NULL;
3044     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3045     // retrieve the chained handler
3046     if (siginfo_flag_set) {
3047       sa = actp->sa_sigaction;
3048     } else {
3049       hand = actp->sa_handler;
3050     }
3051 
3052     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3053       actp->sa_handler = SIG_DFL;
3054     }
3055 
3056     // try to honor the signal mask
3057     sigset_t oset;
3058     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3059 
3060     // call into the chained handler
3061     if (siginfo_flag_set) {
3062       (*sa)(sig, siginfo, context);
3063     } else {
3064       (*hand)(sig);
3065     }
3066 
3067     // restore the signal mask
3068     pthread_sigmask(SIG_SETMASK, &oset, 0);
3069   }
3070   // Tell jvm's signal handler the signal is taken care of.
3071   return true;
3072 }
3073 
3074 bool os::Aix::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3075   bool chained = false;
3076   // signal-chaining
3077   if (UseSignalChaining) {
3078     struct sigaction *actp = get_chained_signal_action(sig);
3079     if (actp != NULL) {
3080       chained = call_chained_handler(actp, sig, siginfo, context);
3081     }
3082   }
3083   return chained;
3084 }
3085 
3086 // for diagnostic
3087 int sigflags[NSIG];
3088 
3089 int os::Aix::get_our_sigflags(int sig) {
3090   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3091   return sigflags[sig];
3092 }
3093 
3094 void os::Aix::set_our_sigflags(int sig, int flags) {
3095   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3096   if (sig > 0 && sig < NSIG) {
3097     sigflags[sig] = flags;
3098   }
3099 }
3100 
3101 void os::Aix::set_signal_handler(int sig, bool set_installed) {
3102   // Check for overwrite.
3103   struct sigaction oldAct;
3104   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3105 
3106   void* oldhand = oldAct.sa_sigaction
3107     ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3108     : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3109   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3110       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3111       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)javaSignalHandler)) {
3112     if (AllowUserSignalHandlers || !set_installed) {
3113       // Do not overwrite; user takes responsibility to forward to us.
3114       return;
3115     } else if (UseSignalChaining) {
3116       // save the old handler in jvm
3117       os::Posix::save_preinstalled_handler(sig, oldAct);
3118       // libjsig also interposes the sigaction() call below and saves the
3119       // old sigaction on it own.
3120     } else {
3121       fatal("Encountered unexpected pre-existing sigaction handler "
3122             "%#lx for signal %d.", (long)oldhand, sig);
3123     }
3124   }
3125 
3126   struct sigaction sigAct;
3127   sigfillset(&(sigAct.sa_mask));
3128   if (!set_installed) {
3129     sigAct.sa_handler = SIG_DFL;
3130     sigAct.sa_flags = SA_RESTART;
3131   } else {
3132     sigAct.sa_sigaction = javaSignalHandler;
3133     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3134   }
3135   // Save flags, which are set by ours
3136   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3137   sigflags[sig] = sigAct.sa_flags;
3138 
3139   int ret = sigaction(sig, &sigAct, &oldAct);
3140   assert(ret == 0, "check");
3141 
3142   void* oldhand2 = oldAct.sa_sigaction
3143                  ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3144                  : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3145   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3146 }
3147 
3148 // install signal handlers for signals that HotSpot needs to
3149 // handle in order to support Java-level exception handling.
3150 void os::Aix::install_signal_handlers() {
3151   if (!signal_handlers_are_installed) {
3152     signal_handlers_are_installed = true;
3153 
3154     // signal-chaining
3155     typedef void (*signal_setting_t)();
3156     signal_setting_t begin_signal_setting = NULL;
3157     signal_setting_t end_signal_setting = NULL;
3158     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3159                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3160     if (begin_signal_setting != NULL) {
3161       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3162                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3163       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3164                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3165       libjsig_is_loaded = true;
3166       assert(UseSignalChaining, "should enable signal-chaining");
3167     }
3168     if (libjsig_is_loaded) {
3169       // Tell libjsig jvm is setting signal handlers.
3170       (*begin_signal_setting)();
3171     }
3172 
3173     set_signal_handler(SIGSEGV, true);
3174     set_signal_handler(SIGPIPE, true);
3175     set_signal_handler(SIGBUS, true);
3176     set_signal_handler(SIGILL, true);
3177     set_signal_handler(SIGFPE, true);
3178     set_signal_handler(SIGTRAP, true);
3179     set_signal_handler(SIGXFSZ, true);
3180 
3181     if (libjsig_is_loaded) {
3182       // Tell libjsig jvm finishes setting signal handlers.
3183       (*end_signal_setting)();
3184     }
3185 
3186     // We don't activate signal checker if libjsig is in place, we trust ourselves
3187     // and if UserSignalHandler is installed all bets are off.
3188     // Log that signal checking is off only if -verbose:jni is specified.
3189     if (CheckJNICalls) {
3190       if (libjsig_is_loaded) {
3191         tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3192         check_signals = false;
3193       }
3194       if (AllowUserSignalHandlers) {
3195         tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3196         check_signals = false;
3197       }
3198       // Need to initialize check_signal_done.
3199       ::sigemptyset(&check_signal_done);
3200     }
3201   }
3202 }
3203 
3204 static const char* get_signal_handler_name(address handler,
3205                                            char* buf, int buflen) {
3206   int offset;
3207   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3208   if (found) {
3209     // skip directory names
3210     const char *p1, *p2;
3211     p1 = buf;
3212     size_t len = strlen(os::file_separator());
3213     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3214     // The way os::dll_address_to_library_name is implemented on Aix
3215     // right now, it always returns -1 for the offset which is not
3216     // terribly informative.
3217     // Will fix that. For now, omit the offset.
3218     jio_snprintf(buf, buflen, "%s", p1);
3219   } else {
3220     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3221   }
3222   return buf;
3223 }
3224 
3225 static void print_signal_handler(outputStream* st, int sig,
3226                                  char* buf, size_t buflen) {
3227   struct sigaction sa;
3228   sigaction(sig, NULL, &sa);
3229 
3230   st->print("%s: ", os::exception_name(sig, buf, buflen));
3231 
3232   address handler = (sa.sa_flags & SA_SIGINFO)
3233     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3234     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3235 
3236   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3237     st->print("SIG_DFL");
3238   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3239     st->print("SIG_IGN");
3240   } else {
3241     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3242   }
3243 
3244   // Print readable mask.
3245   st->print(", sa_mask[0]=");
3246   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3247 
3248   address rh = VMError::get_resetted_sighandler(sig);
3249   // May be, handler was resetted by VMError?
3250   if (rh != NULL) {
3251     handler = rh;
3252     sa.sa_flags = VMError::get_resetted_sigflags(sig);
3253   }
3254 
3255   // Print textual representation of sa_flags.
3256   st->print(", sa_flags=");
3257   os::Posix::print_sa_flags(st, sa.sa_flags);
3258 
3259   // Check: is it our handler?
3260   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler) ||
3261       handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3262     // It is our signal handler.
3263     // Check for flags, reset system-used one!
3264     if ((int)sa.sa_flags != os::Aix::get_our_sigflags(sig)) {
3265       st->print(", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3266                 os::Aix::get_our_sigflags(sig));
3267     }
3268   }
3269   st->cr();
3270 }
3271 
3272 #define DO_SIGNAL_CHECK(sig) \
3273   if (!sigismember(&check_signal_done, sig)) \
3274     os::Aix::check_signal_handler(sig)
3275 
3276 // This method is a periodic task to check for misbehaving JNI applications
3277 // under CheckJNI, we can add any periodic checks here
3278 
3279 void os::run_periodic_checks() {
3280 
3281   if (check_signals == false) return;
3282 
3283   // SEGV and BUS if overridden could potentially prevent
3284   // generation of hs*.log in the event of a crash, debugging
3285   // such a case can be very challenging, so we absolutely
3286   // check the following for a good measure:
3287   DO_SIGNAL_CHECK(SIGSEGV);
3288   DO_SIGNAL_CHECK(SIGILL);
3289   DO_SIGNAL_CHECK(SIGFPE);
3290   DO_SIGNAL_CHECK(SIGBUS);
3291   DO_SIGNAL_CHECK(SIGPIPE);
3292   DO_SIGNAL_CHECK(SIGXFSZ);
3293   if (UseSIGTRAP) {
3294     DO_SIGNAL_CHECK(SIGTRAP);
3295   }
3296 
3297   // ReduceSignalUsage allows the user to override these handlers
3298   // see comments at the very top and jvm_md.h
3299   if (!ReduceSignalUsage) {
3300     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3301     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3302     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3303     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3304   }
3305 
3306   DO_SIGNAL_CHECK(SR_signum);
3307 }
3308 
3309 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3310 
3311 static os_sigaction_t os_sigaction = NULL;
3312 
3313 void os::Aix::check_signal_handler(int sig) {
3314   char buf[O_BUFLEN];
3315   address jvmHandler = NULL;
3316 
3317   struct sigaction act;
3318   if (os_sigaction == NULL) {
3319     // only trust the default sigaction, in case it has been interposed
3320     os_sigaction = CAST_TO_FN_PTR(os_sigaction_t, dlsym(RTLD_DEFAULT, "sigaction"));
3321     if (os_sigaction == NULL) return;
3322   }
3323 
3324   os_sigaction(sig, (struct sigaction*)NULL, &act);
3325 
3326   address thisHandler = (act.sa_flags & SA_SIGINFO)
3327     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3328     : CAST_FROM_FN_PTR(address, act.sa_handler);
3329 
3330   switch(sig) {
3331   case SIGSEGV:
3332   case SIGBUS:
3333   case SIGFPE:
3334   case SIGPIPE:
3335   case SIGILL:
3336   case SIGXFSZ:
3337     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler);
3338     break;
3339 
3340   case SHUTDOWN1_SIGNAL:
3341   case SHUTDOWN2_SIGNAL:
3342   case SHUTDOWN3_SIGNAL:
3343   case BREAK_SIGNAL:
3344     jvmHandler = (address)user_handler();
3345     break;
3346 
3347   default:
3348     if (sig == SR_signum) {
3349       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3350     } else {
3351       return;
3352     }
3353     break;
3354   }
3355 
3356   if (thisHandler != jvmHandler) {
3357     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3358     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3359     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3360     // No need to check this sig any longer
3361     sigaddset(&check_signal_done, sig);
3362     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3363     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3364       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3365                     exception_name(sig, buf, O_BUFLEN));
3366     }
3367   } else if (os::Aix::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Aix::get_our_sigflags(sig)) {
3368     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3369     tty->print("expected:");
3370     os::Posix::print_sa_flags(tty, os::Aix::get_our_sigflags(sig));
3371     tty->cr();
3372     tty->print("  found:");
3373     os::Posix::print_sa_flags(tty, act.sa_flags);
3374     tty->cr();
3375     // No need to check this sig any longer
3376     sigaddset(&check_signal_done, sig);
3377   }
3378 
3379   // Dump all the signal
3380   if (sigismember(&check_signal_done, sig)) {
3381     print_signal_handlers(tty, buf, O_BUFLEN);
3382   }
3383 }
3384 
3385 // To install functions for atexit system call
3386 extern "C" {
3387   static void perfMemory_exit_helper() {
3388     perfMemory_exit();
3389   }
3390 }
3391 
3392 // This is called _before_ the most of global arguments have been parsed.
3393 void os::init(void) {
3394   // This is basic, we want to know if that ever changes.
3395   // (Shared memory boundary is supposed to be a 256M aligned.)
3396   assert(SHMLBA == ((uint64_t)0x10000000ULL)/*256M*/, "unexpected");
3397 
3398   // Record process break at startup.
3399   g_brk_at_startup = (address) ::sbrk(0);
3400   assert(g_brk_at_startup != (address) -1, "sbrk failed");
3401 
3402   // First off, we need to know whether we run on AIX or PASE, and
3403   // the OS level we run on.
3404   os::Aix::initialize_os_info();
3405 
3406   // Scan environment (SPEC1170 behaviour, etc).
3407   os::Aix::scan_environment();
3408 
3409   // Probe multipage support.
3410   query_multipage_support();
3411 
3412   // Act like we only have one page size by eliminating corner cases which
3413   // we did not support very well anyway.
3414   // We have two input conditions:
3415   // 1) Data segment page size. This is controlled by linker setting (datapsize) on the
3416   //    launcher, and/or by LDR_CNTRL environment variable. The latter overrules the linker
3417   //    setting.
3418   //    Data segment page size is important for us because it defines the thread stack page
3419   //    size, which is needed for guard page handling, stack banging etc.
3420   // 2) The ability to allocate 64k pages dynamically. If this is a given, java heap can
3421   //    and should be allocated with 64k pages.
3422   //
3423   // So, we do the following:
3424   // LDR_CNTRL    can_use_64K_pages_dynamically       what we do                      remarks
3425   // 4K           no                                  4K                              old systems (aix 5.2, as/400 v5r4) or new systems with AME activated
3426   // 4k           yes                                 64k (treat 4k stacks as 64k)    different loader than java and standard settings
3427   // 64k          no              --- AIX 5.2 ? ---
3428   // 64k          yes                                 64k                             new systems and standard java loader (we set datapsize=64k when linking)
3429 
3430   // We explicitly leave no option to change page size, because only upgrading would work,
3431   // not downgrading (if stack page size is 64k you cannot pretend its 4k).
3432 
3433   if (g_multipage_support.datapsize == 4*K) {
3434     // datapsize = 4K. Data segment, thread stacks are 4K paged.
3435     if (g_multipage_support.can_use_64K_pages) {
3436       // .. but we are able to use 64K pages dynamically.
3437       // This would be typical for java launchers which are not linked
3438       // with datapsize=64K (like, any other launcher but our own).
3439       //
3440       // In this case it would be smart to allocate the java heap with 64K
3441       // to get the performance benefit, and to fake 64k pages for the
3442       // data segment (when dealing with thread stacks).
3443       //
3444       // However, leave a possibility to downgrade to 4K, using
3445       // -XX:-Use64KPages.
3446       if (Use64KPages) {
3447         trcVerbose("64K page mode (faked for data segment)");
3448         Aix::_page_size = 64*K;
3449       } else {
3450         trcVerbose("4K page mode (Use64KPages=off)");
3451         Aix::_page_size = 4*K;
3452       }
3453     } else {
3454       // .. and not able to allocate 64k pages dynamically. Here, just
3455       // fall back to 4K paged mode and use mmap for everything.
3456       trcVerbose("4K page mode");
3457       Aix::_page_size = 4*K;
3458       FLAG_SET_ERGO(Use64KPages, false);
3459     }
3460   } else {
3461     // datapsize = 64k. Data segment, thread stacks are 64k paged.
3462     // This normally means that we can allocate 64k pages dynamically.
3463     // (There is one special case where this may be false: EXTSHM=on.
3464     // but we decided to not support that mode).
3465     assert0(g_multipage_support.can_use_64K_pages);
3466     Aix::_page_size = 64*K;
3467     trcVerbose("64K page mode");
3468     FLAG_SET_ERGO(Use64KPages, true);
3469   }
3470 
3471   // For now UseLargePages is just ignored.
3472   FLAG_SET_ERGO(UseLargePages, false);
3473   _page_sizes[0] = 0;
3474 
3475   // debug trace
3476   trcVerbose("os::vm_page_size %s", describe_pagesize(os::vm_page_size()));
3477 
3478   // Next, we need to initialize libo4 and libperfstat libraries.
3479   if (os::Aix::on_pase()) {
3480     os::Aix::initialize_libo4();
3481   } else {
3482     os::Aix::initialize_libperfstat();
3483   }
3484 
3485   // Reset the perfstat information provided by ODM.
3486   if (os::Aix::on_aix()) {
3487     libperfstat::perfstat_reset();
3488   }
3489 
3490   // Now initialze basic system properties. Note that for some of the values we
3491   // need libperfstat etc.
3492   os::Aix::initialize_system_info();
3493 
3494   clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3495 
3496   init_random(1234567);
3497 
3498   // _main_thread points to the thread that created/loaded the JVM.
3499   Aix::_main_thread = pthread_self();
3500 
3501   initial_time_count = os::elapsed_counter();
3502 
3503   os::Posix::init();
3504 }
3505 
3506 // This is called _after_ the global arguments have been parsed.
3507 jint os::init_2(void) {
3508 
3509   // This could be set after os::Posix::init() but all platforms
3510   // have to set it the same so we have to mirror Solaris.
3511   DEBUG_ONLY(os::set_mutex_init_done();)
3512 
3513   os::Posix::init_2();
3514 
3515   if (os::Aix::on_pase()) {
3516     trcVerbose("Running on PASE.");
3517   } else {
3518     trcVerbose("Running on AIX (not PASE).");
3519   }
3520 
3521   trcVerbose("processor count: %d", os::_processor_count);
3522   trcVerbose("physical memory: %lu", Aix::_physical_memory);
3523 
3524   // Initially build up the loaded dll map.
3525   LoadedLibraries::reload();
3526   if (Verbose) {
3527     trcVerbose("Loaded Libraries: ");
3528     LoadedLibraries::print(tty);
3529   }
3530 
3531   // initialize suspend/resume support - must do this before signal_sets_init()
3532   if (SR_initialize() != 0) {
3533     perror("SR_initialize failed");
3534     return JNI_ERR;
3535   }
3536 
3537   Aix::signal_sets_init();
3538   Aix::install_signal_handlers();
3539   // Initialize data for jdk.internal.misc.Signal
3540   if (!ReduceSignalUsage) {
3541     jdk_misc_signal_init();
3542   }
3543 
3544   // Check and sets minimum stack sizes against command line options
3545   if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
3546     return JNI_ERR;
3547   }
3548 
3549   if (UseNUMA) {
3550     UseNUMA = false;
3551     warning("NUMA optimizations are not available on this OS.");
3552   }
3553 
3554   if (MaxFDLimit) {
3555     // Set the number of file descriptors to max. print out error
3556     // if getrlimit/setrlimit fails but continue regardless.
3557     struct rlimit nbr_files;
3558     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3559     if (status != 0) {
3560       log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
3561     } else {
3562       nbr_files.rlim_cur = nbr_files.rlim_max;
3563       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3564       if (status != 0) {
3565         log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
3566       }
3567     }
3568   }
3569 
3570   if (PerfAllowAtExitRegistration) {
3571     // Only register atexit functions if PerfAllowAtExitRegistration is set.
3572     // At exit functions can be delayed until process exit time, which
3573     // can be problematic for embedded VM situations. Embedded VMs should
3574     // call DestroyJavaVM() to assure that VM resources are released.
3575 
3576     // Note: perfMemory_exit_helper atexit function may be removed in
3577     // the future if the appropriate cleanup code can be added to the
3578     // VM_Exit VMOperation's doit method.
3579     if (atexit(perfMemory_exit_helper) != 0) {
3580       warning("os::init_2 atexit(perfMemory_exit_helper) failed");
3581     }
3582   }
3583 
3584   return JNI_OK;
3585 }
3586 
3587 // Mark the polling page as unreadable
3588 void os::make_polling_page_unreadable(void) {
3589   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
3590     fatal("Could not disable polling page");
3591   }
3592 };
3593 
3594 // Mark the polling page as readable
3595 void os::make_polling_page_readable(void) {
3596   // Changed according to os_linux.cpp.
3597   if (!checked_mprotect((char *)_polling_page, Aix::page_size(), PROT_READ)) {
3598     fatal("Could not enable polling page at " PTR_FORMAT, _polling_page);
3599   }
3600 };
3601 
3602 int os::active_processor_count() {
3603   // User has overridden the number of active processors
3604   if (ActiveProcessorCount > 0) {
3605     log_trace(os)("active_processor_count: "
3606                   "active processor count set by user : %d",
3607                   ActiveProcessorCount);
3608     return ActiveProcessorCount;
3609   }
3610 
3611   int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3612   assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3613   return online_cpus;
3614 }
3615 
3616 void os::set_native_thread_name(const char *name) {
3617   // Not yet implemented.
3618   return;
3619 }
3620 
3621 bool os::distribute_processes(uint length, uint* distribution) {
3622   // Not yet implemented.
3623   return false;
3624 }
3625 
3626 bool os::bind_to_processor(uint processor_id) {
3627   // Not yet implemented.
3628   return false;
3629 }
3630 
3631 void os::SuspendedThreadTask::internal_do_task() {
3632   if (do_suspend(_thread->osthread())) {
3633     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3634     do_task(context);
3635     do_resume(_thread->osthread());
3636   }
3637 }
3638 
3639 ////////////////////////////////////////////////////////////////////////////////
3640 // debug support
3641 
3642 bool os::find(address addr, outputStream* st) {
3643 
3644   st->print(PTR_FORMAT ": ", addr);
3645 
3646   loaded_module_t lm;
3647   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL ||
3648       LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
3649     st->print_cr("%s", lm.path);
3650     return true;
3651   }
3652 
3653   return false;
3654 }
3655 
3656 ////////////////////////////////////////////////////////////////////////////////
3657 // misc
3658 
3659 // This does not do anything on Aix. This is basically a hook for being
3660 // able to use structured exception handling (thread-local exception filters)
3661 // on, e.g., Win32.
3662 void
3663 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
3664                          JavaCallArguments* args, Thread* thread) {
3665   f(value, method, args, thread);
3666 }
3667 
3668 void os::print_statistics() {
3669 }
3670 
3671 bool os::message_box(const char* title, const char* message) {
3672   int i;
3673   fdStream err(defaultStream::error_fd());
3674   for (i = 0; i < 78; i++) err.print_raw("=");
3675   err.cr();
3676   err.print_raw_cr(title);
3677   for (i = 0; i < 78; i++) err.print_raw("-");
3678   err.cr();
3679   err.print_raw_cr(message);
3680   for (i = 0; i < 78; i++) err.print_raw("=");
3681   err.cr();
3682 
3683   char buf[16];
3684   // Prevent process from exiting upon "read error" without consuming all CPU
3685   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3686 
3687   return buf[0] == 'y' || buf[0] == 'Y';
3688 }
3689 
3690 // Is a (classpath) directory empty?
3691 bool os::dir_is_empty(const char* path) {
3692   DIR *dir = NULL;
3693   struct dirent *ptr;
3694 
3695   dir = opendir(path);
3696   if (dir == NULL) return true;
3697 
3698   /* Scan the directory */
3699   bool result = true;
3700   while (result && (ptr = readdir(dir)) != NULL) {
3701     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3702       result = false;
3703     }
3704   }
3705   closedir(dir);
3706   return result;
3707 }
3708 
3709 // This code originates from JDK's sysOpen and open64_w
3710 // from src/solaris/hpi/src/system_md.c
3711 
3712 int os::open(const char *path, int oflag, int mode) {
3713 
3714   if (strlen(path) > MAX_PATH - 1) {
3715     errno = ENAMETOOLONG;
3716     return -1;
3717   }
3718   int fd;
3719 
3720   fd = ::open64(path, oflag, mode);
3721   if (fd == -1) return -1;
3722 
3723   // If the open succeeded, the file might still be a directory.
3724   {
3725     struct stat64 buf64;
3726     int ret = ::fstat64(fd, &buf64);
3727     int st_mode = buf64.st_mode;
3728 
3729     if (ret != -1) {
3730       if ((st_mode & S_IFMT) == S_IFDIR) {
3731         errno = EISDIR;
3732         ::close(fd);
3733         return -1;
3734       }
3735     } else {
3736       ::close(fd);
3737       return -1;
3738     }
3739   }
3740 
3741   // All file descriptors that are opened in the JVM and not
3742   // specifically destined for a subprocess should have the
3743   // close-on-exec flag set. If we don't set it, then careless 3rd
3744   // party native code might fork and exec without closing all
3745   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3746   // UNIXProcess.c), and this in turn might:
3747   //
3748   // - cause end-of-file to fail to be detected on some file
3749   //   descriptors, resulting in mysterious hangs, or
3750   //
3751   // - might cause an fopen in the subprocess to fail on a system
3752   //   suffering from bug 1085341.
3753   //
3754   // (Yes, the default setting of the close-on-exec flag is a Unix
3755   // design flaw.)
3756   //
3757   // See:
3758   // 1085341: 32-bit stdio routines should support file descriptors >255
3759   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3760   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3761 #ifdef FD_CLOEXEC
3762   {
3763     int flags = ::fcntl(fd, F_GETFD);
3764     if (flags != -1)
3765       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3766   }
3767 #endif
3768 
3769   return fd;
3770 }
3771 
3772 // create binary file, rewriting existing file if required
3773 int os::create_binary_file(const char* path, bool rewrite_existing) {
3774   int oflags = O_WRONLY | O_CREAT;
3775   if (!rewrite_existing) {
3776     oflags |= O_EXCL;
3777   }
3778   return ::open64(path, oflags, S_IREAD | S_IWRITE);
3779 }
3780 
3781 // return current position of file pointer
3782 jlong os::current_file_offset(int fd) {
3783   return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
3784 }
3785 
3786 // move file pointer to the specified offset
3787 jlong os::seek_to_file_offset(int fd, jlong offset) {
3788   return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
3789 }
3790 
3791 // This code originates from JDK's sysAvailable
3792 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3793 
3794 int os::available(int fd, jlong *bytes) {
3795   jlong cur, end;
3796   int mode;
3797   struct stat64 buf64;
3798 
3799   if (::fstat64(fd, &buf64) >= 0) {
3800     mode = buf64.st_mode;
3801     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3802       int n;
3803       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3804         *bytes = n;
3805         return 1;
3806       }
3807     }
3808   }
3809   if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
3810     return 0;
3811   } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
3812     return 0;
3813   } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
3814     return 0;
3815   }
3816   *bytes = end - cur;
3817   return 1;
3818 }
3819 
3820 // Map a block of memory.
3821 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3822                         char *addr, size_t bytes, bool read_only,
3823                         bool allow_exec) {
3824   int prot;
3825   int flags = MAP_PRIVATE;
3826 
3827   if (read_only) {
3828     prot = PROT_READ;
3829     flags = MAP_SHARED;
3830   } else {
3831     prot = PROT_READ | PROT_WRITE;
3832     flags = MAP_PRIVATE;
3833   }
3834 
3835   if (allow_exec) {
3836     prot |= PROT_EXEC;
3837   }
3838 
3839   if (addr != NULL) {
3840     flags |= MAP_FIXED;
3841   }
3842 
3843   // Allow anonymous mappings if 'fd' is -1.
3844   if (fd == -1) {
3845     flags |= MAP_ANONYMOUS;
3846   }
3847 
3848   char* mapped_address = (char*)::mmap(addr, (size_t)bytes, prot, flags,
3849                                      fd, file_offset);
3850   if (mapped_address == MAP_FAILED) {
3851     return NULL;
3852   }
3853   return mapped_address;
3854 }
3855 
3856 // Remap a block of memory.
3857 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3858                           char *addr, size_t bytes, bool read_only,
3859                           bool allow_exec) {
3860   // same as map_memory() on this OS
3861   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3862                         allow_exec);
3863 }
3864 
3865 // Unmap a block of memory.
3866 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3867   return munmap(addr, bytes) == 0;
3868 }
3869 
3870 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3871 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3872 // of a thread.
3873 //
3874 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3875 // the fast estimate available on the platform.
3876 
3877 jlong os::current_thread_cpu_time() {
3878   // return user + sys since the cost is the same
3879   const jlong n = os::thread_cpu_time(Thread::current(), true /* user + sys */);
3880   assert(n >= 0, "negative CPU time");
3881   return n;
3882 }
3883 
3884 jlong os::thread_cpu_time(Thread* thread) {
3885   // consistent with what current_thread_cpu_time() returns
3886   const jlong n = os::thread_cpu_time(thread, true /* user + sys */);
3887   assert(n >= 0, "negative CPU time");
3888   return n;
3889 }
3890 
3891 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
3892   const jlong n = os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
3893   assert(n >= 0, "negative CPU time");
3894   return n;
3895 }
3896 
3897 static bool thread_cpu_time_unchecked(Thread* thread, jlong* p_sys_time, jlong* p_user_time) {
3898   bool error = false;
3899 
3900   jlong sys_time = 0;
3901   jlong user_time = 0;
3902 
3903   // Reimplemented using getthrds64().
3904   //
3905   // Works like this:
3906   // For the thread in question, get the kernel thread id. Then get the
3907   // kernel thread statistics using that id.
3908   //
3909   // This only works of course when no pthread scheduling is used,
3910   // i.e. there is a 1:1 relationship to kernel threads.
3911   // On AIX, see AIXTHREAD_SCOPE variable.
3912 
3913   pthread_t pthtid = thread->osthread()->pthread_id();
3914 
3915   // retrieve kernel thread id for the pthread:
3916   tid64_t tid = 0;
3917   struct __pthrdsinfo pinfo;
3918   // I just love those otherworldly IBM APIs which force me to hand down
3919   // dummy buffers for stuff I dont care for...
3920   char dummy[1];
3921   int dummy_size = sizeof(dummy);
3922   if (pthread_getthrds_np(&pthtid, PTHRDSINFO_QUERY_TID, &pinfo, sizeof(pinfo),
3923                           dummy, &dummy_size) == 0) {
3924     tid = pinfo.__pi_tid;
3925   } else {
3926     tty->print_cr("pthread_getthrds_np failed.");
3927     error = true;
3928   }
3929 
3930   // retrieve kernel timing info for that kernel thread
3931   if (!error) {
3932     struct thrdentry64 thrdentry;
3933     if (getthrds64(getpid(), &thrdentry, sizeof(thrdentry), &tid, 1) == 1) {
3934       sys_time = thrdentry.ti_ru.ru_stime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_stime.tv_usec * 1000LL;
3935       user_time = thrdentry.ti_ru.ru_utime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_utime.tv_usec * 1000LL;
3936     } else {
3937       tty->print_cr("pthread_getthrds_np failed.");
3938       error = true;
3939     }
3940   }
3941 
3942   if (p_sys_time) {
3943     *p_sys_time = sys_time;
3944   }
3945 
3946   if (p_user_time) {
3947     *p_user_time = user_time;
3948   }
3949 
3950   if (error) {
3951     return false;
3952   }
3953 
3954   return true;
3955 }
3956 
3957 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
3958   jlong sys_time;
3959   jlong user_time;
3960 
3961   if (!thread_cpu_time_unchecked(thread, &sys_time, &user_time)) {
3962     return -1;
3963   }
3964 
3965   return user_sys_cpu_time ? sys_time + user_time : user_time;
3966 }
3967 
3968 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
3969   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
3970   info_ptr->may_skip_backward = false;     // elapsed time not wall time
3971   info_ptr->may_skip_forward = false;      // elapsed time not wall time
3972   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
3973 }
3974 
3975 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
3976   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
3977   info_ptr->may_skip_backward = false;     // elapsed time not wall time
3978   info_ptr->may_skip_forward = false;      // elapsed time not wall time
3979   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
3980 }
3981 
3982 bool os::is_thread_cpu_time_supported() {
3983   return true;
3984 }
3985 
3986 // System loadavg support. Returns -1 if load average cannot be obtained.
3987 // For now just return the system wide load average (no processor sets).
3988 int os::loadavg(double values[], int nelem) {
3989 
3990   guarantee(nelem >= 0 && nelem <= 3, "argument error");
3991   guarantee(values, "argument error");
3992 
3993   if (os::Aix::on_pase()) {
3994 
3995     // AS/400 PASE: use libo4 porting library
3996     double v[3] = { 0.0, 0.0, 0.0 };
3997 
3998     if (libo4::get_load_avg(v, v + 1, v + 2)) {
3999       for (int i = 0; i < nelem; i ++) {
4000         values[i] = v[i];
4001       }
4002       return nelem;
4003     } else {
4004       return -1;
4005     }
4006 
4007   } else {
4008 
4009     // AIX: use libperfstat
4010     libperfstat::cpuinfo_t ci;
4011     if (libperfstat::get_cpuinfo(&ci)) {
4012       for (int i = 0; i < nelem; i++) {
4013         values[i] = ci.loadavg[i];
4014       }
4015     } else {
4016       return -1;
4017     }
4018     return nelem;
4019   }
4020 }
4021 
4022 void os::pause() {
4023   char filename[MAX_PATH];
4024   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4025     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4026   } else {
4027     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4028   }
4029 
4030   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4031   if (fd != -1) {
4032     struct stat buf;
4033     ::close(fd);
4034     while (::stat(filename, &buf) == 0) {
4035       (void)::poll(NULL, 0, 100);
4036     }
4037   } else {
4038     trcVerbose("Could not open pause file '%s', continuing immediately.", filename);
4039   }
4040 }
4041 
4042 bool os::is_primordial_thread(void) {
4043   if (pthread_self() == (pthread_t)1) {
4044     return true;
4045   } else {
4046     return false;
4047   }
4048 }
4049 
4050 // OS recognitions (PASE/AIX, OS level) call this before calling any
4051 // one of Aix::on_pase(), Aix::os_version() static
4052 void os::Aix::initialize_os_info() {
4053 
4054   assert(_on_pase == -1 && _os_version == 0, "already called.");
4055 
4056   struct utsname uts;
4057   memset(&uts, 0, sizeof(uts));
4058   strcpy(uts.sysname, "?");
4059   if (::uname(&uts) == -1) {
4060     trcVerbose("uname failed (%d)", errno);
4061     guarantee(0, "Could not determine whether we run on AIX or PASE");
4062   } else {
4063     trcVerbose("uname says: sysname \"%s\" version \"%s\" release \"%s\" "
4064                "node \"%s\" machine \"%s\"\n",
4065                uts.sysname, uts.version, uts.release, uts.nodename, uts.machine);
4066     const int major = atoi(uts.version);
4067     assert(major > 0, "invalid OS version");
4068     const int minor = atoi(uts.release);
4069     assert(minor > 0, "invalid OS release");
4070     _os_version = (major << 24) | (minor << 16);
4071     char ver_str[20] = {0};
4072     const char* name_str = "unknown OS";
4073     if (strcmp(uts.sysname, "OS400") == 0) {
4074       // We run on AS/400 PASE. We do not support versions older than V5R4M0.
4075       _on_pase = 1;
4076       if (os_version_short() < 0x0504) {
4077         trcVerbose("OS/400 releases older than V5R4M0 not supported.");
4078         assert(false, "OS/400 release too old.");
4079       }
4080       name_str = "OS/400 (pase)";
4081       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u", major, minor);
4082     } else if (strcmp(uts.sysname, "AIX") == 0) {
4083       // We run on AIX. We do not support versions older than AIX 7.1.
4084       _on_pase = 0;
4085       // Determine detailed AIX version: Version, Release, Modification, Fix Level.
4086       odmWrapper::determine_os_kernel_version(&_os_version);
4087       if (os_version_short() < 0x0701) {
4088         trcVerbose("AIX releases older than AIX 7.1 are not supported.");
4089         assert(false, "AIX release too old.");
4090       }
4091       name_str = "AIX";
4092       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u.%u.%u",
4093                    major, minor, (_os_version >> 8) & 0xFF, _os_version & 0xFF);
4094     } else {
4095       assert(false, "%s", name_str);
4096     }
4097     trcVerbose("We run on %s %s", name_str, ver_str);
4098   }
4099 
4100   guarantee(_on_pase != -1 && _os_version, "Could not determine AIX/OS400 release");
4101 } // end: os::Aix::initialize_os_info()
4102 
4103 // Scan environment for important settings which might effect the VM.
4104 // Trace out settings. Warn about invalid settings and/or correct them.
4105 //
4106 // Must run after os::Aix::initialue_os_info().
4107 void os::Aix::scan_environment() {
4108 
4109   char* p;
4110   int rc;
4111 
4112   // Warn explicity if EXTSHM=ON is used. That switch changes how
4113   // System V shared memory behaves. One effect is that page size of
4114   // shared memory cannot be change dynamically, effectivly preventing
4115   // large pages from working.
4116   // This switch was needed on AIX 32bit, but on AIX 64bit the general
4117   // recommendation is (in OSS notes) to switch it off.
4118   p = ::getenv("EXTSHM");
4119   trcVerbose("EXTSHM=%s.", p ? p : "<unset>");
4120   if (p && strcasecmp(p, "ON") == 0) {
4121     _extshm = 1;
4122     trcVerbose("*** Unsupported mode! Please remove EXTSHM from your environment! ***");
4123     if (!AllowExtshm) {
4124       // We allow under certain conditions the user to continue. However, we want this
4125       // to be a fatal error by default. On certain AIX systems, leaving EXTSHM=ON means
4126       // that the VM is not able to allocate 64k pages for the heap.
4127       // We do not want to run with reduced performance.
4128       vm_exit_during_initialization("EXTSHM is ON. Please remove EXTSHM from your environment.");
4129     }
4130   } else {
4131     _extshm = 0;
4132   }
4133 
4134   // SPEC1170 behaviour: will change the behaviour of a number of POSIX APIs.
4135   // Not tested, not supported.
4136   //
4137   // Note that it might be worth the trouble to test and to require it, if only to
4138   // get useful return codes for mprotect.
4139   //
4140   // Note: Setting XPG_SUS_ENV in the process is too late. Must be set earlier (before
4141   // exec() ? before loading the libjvm ? ....)
4142   p = ::getenv("XPG_SUS_ENV");
4143   trcVerbose("XPG_SUS_ENV=%s.", p ? p : "<unset>");
4144   if (p && strcmp(p, "ON") == 0) {
4145     _xpg_sus_mode = 1;
4146     trcVerbose("Unsupported setting: XPG_SUS_ENV=ON");
4147     // This is not supported. Worst of all, it changes behaviour of mmap MAP_FIXED to
4148     // clobber address ranges. If we ever want to support that, we have to do some
4149     // testing first.
4150     guarantee(false, "XPG_SUS_ENV=ON not supported");
4151   } else {
4152     _xpg_sus_mode = 0;
4153   }
4154 
4155   if (os::Aix::on_pase()) {
4156     p = ::getenv("QIBM_MULTI_THREADED");
4157     trcVerbose("QIBM_MULTI_THREADED=%s.", p ? p : "<unset>");
4158   }
4159 
4160   p = ::getenv("LDR_CNTRL");
4161   trcVerbose("LDR_CNTRL=%s.", p ? p : "<unset>");
4162   if (os::Aix::on_pase() && os::Aix::os_version_short() == 0x0701) {
4163     if (p && ::strstr(p, "TEXTPSIZE")) {
4164       trcVerbose("*** WARNING - LDR_CNTRL contains TEXTPSIZE. "
4165         "you may experience hangs or crashes on OS/400 V7R1.");
4166     }
4167   }
4168 
4169   p = ::getenv("AIXTHREAD_GUARDPAGES");
4170   trcVerbose("AIXTHREAD_GUARDPAGES=%s.", p ? p : "<unset>");
4171 
4172 } // end: os::Aix::scan_environment()
4173 
4174 // PASE: initialize the libo4 library (PASE porting library).
4175 void os::Aix::initialize_libo4() {
4176   guarantee(os::Aix::on_pase(), "OS/400 only.");
4177   if (!libo4::init()) {
4178     trcVerbose("libo4 initialization failed.");
4179     assert(false, "libo4 initialization failed");
4180   } else {
4181     trcVerbose("libo4 initialized.");
4182   }
4183 }
4184 
4185 // AIX: initialize the libperfstat library.
4186 void os::Aix::initialize_libperfstat() {
4187   assert(os::Aix::on_aix(), "AIX only");
4188   if (!libperfstat::init()) {
4189     trcVerbose("libperfstat initialization failed.");
4190     assert(false, "libperfstat initialization failed");
4191   } else {
4192     trcVerbose("libperfstat initialized.");
4193   }
4194 }
4195 
4196 /////////////////////////////////////////////////////////////////////////////
4197 // thread stack
4198 
4199 // Get the current stack base from the OS (actually, the pthread library).
4200 // Note: usually not page aligned.
4201 address os::current_stack_base() {
4202   AixMisc::stackbounds_t bounds;
4203   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4204   guarantee(rc, "Unable to retrieve stack bounds.");
4205   return bounds.base;
4206 }
4207 
4208 // Get the current stack size from the OS (actually, the pthread library).
4209 // Returned size is such that (base - size) is always aligned to page size.
4210 size_t os::current_stack_size() {
4211   AixMisc::stackbounds_t bounds;
4212   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4213   guarantee(rc, "Unable to retrieve stack bounds.");
4214   // Align the returned stack size such that the stack low address
4215   // is aligned to page size (Note: base is usually not and we do not care).
4216   // We need to do this because caller code will assume stack low address is
4217   // page aligned and will place guard pages without checking.
4218   address low = bounds.base - bounds.size;
4219   address low_aligned = (address)align_up(low, os::vm_page_size());
4220   size_t s = bounds.base - low_aligned;
4221   return s;
4222 }
4223 
4224 extern char** environ;
4225 
4226 // Run the specified command in a separate process. Return its exit value,
4227 // or -1 on failure (e.g. can't fork a new process).
4228 // Unlike system(), this function can be called from signal handler. It
4229 // doesn't block SIGINT et al.
4230 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
4231   char * argv[4] = {"sh", "-c", cmd, NULL};
4232 
4233   pid_t pid = fork();
4234 
4235   if (pid < 0) {
4236     // fork failed
4237     return -1;
4238 
4239   } else if (pid == 0) {
4240     // child process
4241 
4242     // Try to be consistent with system(), which uses "/usr/bin/sh" on AIX.
4243     execve("/usr/bin/sh", argv, environ);
4244 
4245     // execve failed
4246     _exit(-1);
4247 
4248   } else {
4249     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4250     // care about the actual exit code, for now.
4251 
4252     int status;
4253 
4254     // Wait for the child process to exit. This returns immediately if
4255     // the child has already exited. */
4256     while (waitpid(pid, &status, 0) < 0) {
4257       switch (errno) {
4258         case ECHILD: return 0;
4259         case EINTR: break;
4260         default: return -1;
4261       }
4262     }
4263 
4264     if (WIFEXITED(status)) {
4265       // The child exited normally; get its exit code.
4266       return WEXITSTATUS(status);
4267     } else if (WIFSIGNALED(status)) {
4268       // The child exited because of a signal.
4269       // The best value to return is 0x80 + signal number,
4270       // because that is what all Unix shells do, and because
4271       // it allows callers to distinguish between process exit and
4272       // process death by signal.
4273       return 0x80 + WTERMSIG(status);
4274     } else {
4275       // Unknown exit code; pass it through.
4276       return status;
4277     }
4278   }
4279   return -1;
4280 }
4281 
4282 // Get the default path to the core file
4283 // Returns the length of the string
4284 int os::get_core_path(char* buffer, size_t bufferSize) {
4285   const char* p = get_current_directory(buffer, bufferSize);
4286 
4287   if (p == NULL) {
4288     assert(p != NULL, "failed to get current directory");
4289     return 0;
4290   }
4291 
4292   jio_snprintf(buffer, bufferSize, "%s/core or core.%d",
4293                                                p, current_process_id());
4294 
4295   return strlen(buffer);
4296 }
4297 
4298 #ifndef PRODUCT
4299 void TestReserveMemorySpecial_test() {
4300   // No tests available for this platform
4301 }
4302 #endif
4303 
4304 bool os::start_debugging(char *buf, int buflen) {
4305   int len = (int)strlen(buf);
4306   char *p = &buf[len];
4307 
4308   jio_snprintf(p, buflen -len,
4309                  "\n\n"
4310                  "Do you want to debug the problem?\n\n"
4311                  "To debug, run 'dbx -a %d'; then switch to thread tid " INTX_FORMAT ", k-tid " INTX_FORMAT "\n"
4312                  "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
4313                  "Otherwise, press RETURN to abort...",
4314                  os::current_process_id(),
4315                  os::current_thread_id(), thread_self());
4316 
4317   bool yes = os::message_box("Unexpected Error", buf);
4318 
4319   if (yes) {
4320     // yes, user asked VM to launch debugger
4321     jio_snprintf(buf, buflen, "dbx -a %d", os::current_process_id());
4322 
4323     os::fork_and_exec(buf);
4324     yes = false;
4325   }
4326   return yes;
4327 }
4328 
4329 static inline time_t get_mtime(const char* filename) {
4330   struct stat st;
4331   int ret = os::stat(filename, &st);
4332   assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
4333   return st.st_mtime;
4334 }
4335 
4336 int os::compare_file_modified_times(const char* file1, const char* file2) {
4337   time_t t1 = get_mtime(file1);
4338   time_t t2 = get_mtime(file2);
4339   return t1 - t2;
4340 }
4341 
4342 bool os::supports_map_sync() {
4343   return false;
4344 }