1 /*
   2  * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 // According to the AIX OS doc #pragma alloca must be used
  27 // with C++ compiler before referencing the function alloca()
  28 #pragma alloca
  29 
  30 // no precompiled headers
  31 #include "jvm.h"
  32 #include "classfile/classLoader.hpp"
  33 #include "classfile/systemDictionary.hpp"
  34 #include "classfile/vmSymbols.hpp"
  35 #include "code/icBuffer.hpp"
  36 #include "code/vtableStubs.hpp"
  37 #include "compiler/compileBroker.hpp"
  38 #include "interpreter/interpreter.hpp"
  39 #include "logging/log.hpp"
  40 #include "libo4.hpp"
  41 #include "libperfstat_aix.hpp"
  42 #include "libodm_aix.hpp"
  43 #include "loadlib_aix.hpp"
  44 #include "memory/allocation.inline.hpp"
  45 #include "memory/filemap.hpp"
  46 #include "misc_aix.hpp"
  47 #include "oops/oop.inline.hpp"
  48 #include "os_aix.inline.hpp"
  49 #include "os_share_aix.hpp"
  50 #include "porting_aix.hpp"
  51 #include "prims/jniFastGetField.hpp"
  52 #include "prims/jvm_misc.hpp"
  53 #include "runtime/arguments.hpp"
  54 #include "runtime/atomic.hpp"
  55 #include "runtime/extendedPC.hpp"
  56 #include "runtime/globals.hpp"
  57 #include "runtime/interfaceSupport.inline.hpp"
  58 #include "runtime/java.hpp"
  59 #include "runtime/javaCalls.hpp"
  60 #include "runtime/mutexLocker.hpp"
  61 #include "runtime/objectMonitor.hpp"
  62 #include "runtime/orderAccess.inline.hpp"
  63 #include "runtime/os.hpp"
  64 #include "runtime/osThread.hpp"
  65 #include "runtime/perfMemory.hpp"
  66 #include "runtime/sharedRuntime.hpp"
  67 #include "runtime/statSampler.hpp"
  68 #include "runtime/stubRoutines.hpp"
  69 #include "runtime/thread.inline.hpp"
  70 #include "runtime/threadCritical.hpp"
  71 #include "runtime/timer.hpp"
  72 #include "runtime/vm_version.hpp"
  73 #include "services/attachListener.hpp"
  74 #include "services/runtimeService.hpp"
  75 #include "utilities/align.hpp"
  76 #include "utilities/decoder.hpp"
  77 #include "utilities/defaultStream.hpp"
  78 #include "utilities/events.hpp"
  79 #include "utilities/growableArray.hpp"
  80 #include "utilities/vmError.hpp"
  81 
  82 // put OS-includes here (sorted alphabetically)
  83 #include <errno.h>
  84 #include <fcntl.h>
  85 #include <inttypes.h>
  86 #include <poll.h>
  87 #include <procinfo.h>
  88 #include <pthread.h>
  89 #include <pwd.h>
  90 #include <semaphore.h>
  91 #include <signal.h>
  92 #include <stdint.h>
  93 #include <stdio.h>
  94 #include <string.h>
  95 #include <unistd.h>
  96 #include <sys/ioctl.h>
  97 #include <sys/ipc.h>
  98 #include <sys/mman.h>
  99 #include <sys/resource.h>
 100 #include <sys/select.h>
 101 #include <sys/shm.h>
 102 #include <sys/socket.h>
 103 #include <sys/stat.h>
 104 #include <sys/sysinfo.h>
 105 #include <sys/systemcfg.h>
 106 #include <sys/time.h>
 107 #include <sys/times.h>
 108 #include <sys/types.h>
 109 #include <sys/utsname.h>
 110 #include <sys/vminfo.h>
 111 #include <sys/wait.h>
 112 
 113 // Missing prototypes for various system APIs.
 114 extern "C"
 115 int mread_real_time(timebasestruct_t *t, size_t size_of_timebasestruct_t);
 116 
 117 #if !defined(_AIXVERSION_610)
 118 extern "C" int getthrds64(pid_t, struct thrdentry64*, int, tid64_t*, int);
 119 extern "C" int getprocs64(procentry64*, int, fdsinfo*, int, pid_t*, int);
 120 extern "C" int getargs(procsinfo*, int, char*, int);
 121 #endif
 122 
 123 #define MAX_PATH (2 * K)
 124 
 125 // for timer info max values which include all bits
 126 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 127 // for multipage initialization error analysis (in 'g_multipage_error')
 128 #define ERROR_MP_OS_TOO_OLD                          100
 129 #define ERROR_MP_EXTSHM_ACTIVE                       101
 130 #define ERROR_MP_VMGETINFO_FAILED                    102
 131 #define ERROR_MP_VMGETINFO_CLAIMS_NO_SUPPORT_FOR_64K 103
 132 
 133 // excerpts from systemcfg.h that might be missing on older os levels
 134 #ifndef PV_5_Compat
 135   #define PV_5_Compat 0x0F8000   /* Power PC 5 */
 136 #endif
 137 #ifndef PV_6
 138   #define PV_6 0x100000          /* Power PC 6 */
 139 #endif
 140 #ifndef PV_6_1
 141   #define PV_6_1 0x100001        /* Power PC 6 DD1.x */
 142 #endif
 143 #ifndef PV_6_Compat
 144   #define PV_6_Compat 0x108000   /* Power PC 6 */
 145 #endif
 146 #ifndef PV_7
 147   #define PV_7 0x200000          /* Power PC 7 */
 148 #endif
 149 #ifndef PV_7_Compat
 150   #define PV_7_Compat 0x208000   /* Power PC 7 */
 151 #endif
 152 #ifndef PV_8
 153   #define PV_8 0x300000          /* Power PC 8 */
 154 #endif
 155 #ifndef PV_8_Compat
 156   #define PV_8_Compat 0x308000   /* Power PC 8 */
 157 #endif
 158 
 159 static address resolve_function_descriptor_to_code_pointer(address p);
 160 
 161 static void vmembk_print_on(outputStream* os);
 162 
 163 ////////////////////////////////////////////////////////////////////////////////
 164 // global variables (for a description see os_aix.hpp)
 165 
 166 julong    os::Aix::_physical_memory = 0;
 167 
 168 pthread_t os::Aix::_main_thread = ((pthread_t)0);
 169 int       os::Aix::_page_size = -1;
 170 
 171 // -1 = uninitialized, 0 if AIX, 1 if OS/400 pase
 172 int       os::Aix::_on_pase = -1;
 173 
 174 // 0 = uninitialized, otherwise 32 bit number:
 175 //  0xVVRRTTSS
 176 //  VV - major version
 177 //  RR - minor version
 178 //  TT - tech level, if known, 0 otherwise
 179 //  SS - service pack, if known, 0 otherwise
 180 uint32_t  os::Aix::_os_version = 0;
 181 
 182 // -1 = uninitialized, 0 - no, 1 - yes
 183 int       os::Aix::_xpg_sus_mode = -1;
 184 
 185 // -1 = uninitialized, 0 - no, 1 - yes
 186 int       os::Aix::_extshm = -1;
 187 
 188 ////////////////////////////////////////////////////////////////////////////////
 189 // local variables
 190 
 191 static volatile jlong max_real_time = 0;
 192 static jlong    initial_time_count = 0;
 193 static int      clock_tics_per_sec = 100;
 194 static sigset_t check_signal_done;         // For diagnostics to print a message once (see run_periodic_checks)
 195 static bool     check_signals      = true;
 196 static int      SR_signum          = SIGUSR2; // Signal used to suspend/resume a thread (must be > SIGSEGV, see 4355769)
 197 static sigset_t SR_sigset;
 198 
 199 // Process break recorded at startup.
 200 static address g_brk_at_startup = NULL;
 201 
 202 // This describes the state of multipage support of the underlying
 203 // OS. Note that this is of no interest to the outsize world and
 204 // therefore should not be defined in AIX class.
 205 //
 206 // AIX supports four different page sizes - 4K, 64K, 16MB, 16GB. The
 207 // latter two (16M "large" resp. 16G "huge" pages) require special
 208 // setup and are normally not available.
 209 //
 210 // AIX supports multiple page sizes per process, for:
 211 //  - Stack (of the primordial thread, so not relevant for us)
 212 //  - Data - data, bss, heap, for us also pthread stacks
 213 //  - Text - text code
 214 //  - shared memory
 215 //
 216 // Default page sizes can be set via linker options (-bdatapsize, -bstacksize, ...)
 217 // and via environment variable LDR_CNTRL (DATAPSIZE, STACKPSIZE, ...).
 218 //
 219 // For shared memory, page size can be set dynamically via
 220 // shmctl(). Different shared memory regions can have different page
 221 // sizes.
 222 //
 223 // More information can be found at AIBM info center:
 224 //   http://publib.boulder.ibm.com/infocenter/aix/v6r1/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/multiple_page_size_app_support.htm
 225 //
 226 static struct {
 227   size_t pagesize;            // sysconf _SC_PAGESIZE (4K)
 228   size_t datapsize;           // default data page size (LDR_CNTRL DATAPSIZE)
 229   size_t shmpsize;            // default shared memory page size (LDR_CNTRL SHMPSIZE)
 230   size_t pthr_stack_pagesize; // stack page size of pthread threads
 231   size_t textpsize;           // default text page size (LDR_CNTRL STACKPSIZE)
 232   bool can_use_64K_pages;     // True if we can alloc 64K pages dynamically with Sys V shm.
 233   bool can_use_16M_pages;     // True if we can alloc 16M pages dynamically with Sys V shm.
 234   int error;                  // Error describing if something went wrong at multipage init.
 235 } g_multipage_support = {
 236   (size_t) -1,
 237   (size_t) -1,
 238   (size_t) -1,
 239   (size_t) -1,
 240   (size_t) -1,
 241   false, false,
 242   0
 243 };
 244 
 245 // We must not accidentally allocate memory close to the BRK - even if
 246 // that would work - because then we prevent the BRK segment from
 247 // growing which may result in a malloc OOM even though there is
 248 // enough memory. The problem only arises if we shmat() or mmap() at
 249 // a specific wish address, e.g. to place the heap in a
 250 // compressed-oops-friendly way.
 251 static bool is_close_to_brk(address a) {
 252   assert0(g_brk_at_startup != NULL);
 253   if (a >= g_brk_at_startup &&
 254       a < (g_brk_at_startup + MaxExpectedDataSegmentSize)) {
 255     return true;
 256   }
 257   return false;
 258 }
 259 
 260 julong os::available_memory() {
 261   return Aix::available_memory();
 262 }
 263 
 264 julong os::Aix::available_memory() {
 265   // Avoid expensive API call here, as returned value will always be null.
 266   if (os::Aix::on_pase()) {
 267     return 0x0LL;
 268   }
 269   os::Aix::meminfo_t mi;
 270   if (os::Aix::get_meminfo(&mi)) {
 271     return mi.real_free;
 272   } else {
 273     return ULONG_MAX;
 274   }
 275 }
 276 
 277 julong os::physical_memory() {
 278   return Aix::physical_memory();
 279 }
 280 
 281 // Return true if user is running as root.
 282 
 283 bool os::have_special_privileges() {
 284   static bool init = false;
 285   static bool privileges = false;
 286   if (!init) {
 287     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 288     init = true;
 289   }
 290   return privileges;
 291 }
 292 
 293 // Helper function, emulates disclaim64 using multiple 32bit disclaims
 294 // because we cannot use disclaim64() on AS/400 and old AIX releases.
 295 static bool my_disclaim64(char* addr, size_t size) {
 296 
 297   if (size == 0) {
 298     return true;
 299   }
 300 
 301   // Maximum size 32bit disclaim() accepts. (Theoretically 4GB, but I just do not trust that.)
 302   const unsigned int maxDisclaimSize = 0x40000000;
 303 
 304   const unsigned int numFullDisclaimsNeeded = (size / maxDisclaimSize);
 305   const unsigned int lastDisclaimSize = (size % maxDisclaimSize);
 306 
 307   char* p = addr;
 308 
 309   for (int i = 0; i < numFullDisclaimsNeeded; i ++) {
 310     if (::disclaim(p, maxDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 311       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + maxDisclaimSize, errno);
 312       return false;
 313     }
 314     p += maxDisclaimSize;
 315   }
 316 
 317   if (lastDisclaimSize > 0) {
 318     if (::disclaim(p, lastDisclaimSize, DISCLAIM_ZEROMEM) != 0) {
 319       trcVerbose("Cannot disclaim %p - %p (errno %d)\n", p, p + lastDisclaimSize, errno);
 320       return false;
 321     }
 322   }
 323 
 324   return true;
 325 }
 326 
 327 // Cpu architecture string
 328 #if defined(PPC32)
 329 static char cpu_arch[] = "ppc";
 330 #elif defined(PPC64)
 331 static char cpu_arch[] = "ppc64";
 332 #else
 333 #error Add appropriate cpu_arch setting
 334 #endif
 335 
 336 // Wrap the function "vmgetinfo" which is not available on older OS releases.
 337 static int checked_vmgetinfo(void *out, int command, int arg) {
 338   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 339     guarantee(false, "cannot call vmgetinfo on AS/400 older than V6R1");
 340   }
 341   return ::vmgetinfo(out, command, arg);
 342 }
 343 
 344 // Given an address, returns the size of the page backing that address.
 345 size_t os::Aix::query_pagesize(void* addr) {
 346 
 347   if (os::Aix::on_pase() && os::Aix::os_version_short() < 0x0601) {
 348     // AS/400 older than V6R1: no vmgetinfo here, default to 4K
 349     return 4*K;
 350   }
 351 
 352   vm_page_info pi;
 353   pi.addr = (uint64_t)addr;
 354   if (checked_vmgetinfo(&pi, VM_PAGE_INFO, sizeof(pi)) == 0) {
 355     return pi.pagesize;
 356   } else {
 357     assert(false, "vmgetinfo failed to retrieve page size");
 358     return 4*K;
 359   }
 360 }
 361 
 362 void os::Aix::initialize_system_info() {
 363 
 364   // Get the number of online(logical) cpus instead of configured.
 365   os::_processor_count = sysconf(_SC_NPROCESSORS_ONLN);
 366   assert(_processor_count > 0, "_processor_count must be > 0");
 367 
 368   // Retrieve total physical storage.
 369   os::Aix::meminfo_t mi;
 370   if (!os::Aix::get_meminfo(&mi)) {
 371     assert(false, "os::Aix::get_meminfo failed.");
 372   }
 373   _physical_memory = (julong) mi.real_total;
 374 }
 375 
 376 // Helper function for tracing page sizes.
 377 static const char* describe_pagesize(size_t pagesize) {
 378   switch (pagesize) {
 379     case 4*K : return "4K";
 380     case 64*K: return "64K";
 381     case 16*M: return "16M";
 382     case 16*G: return "16G";
 383     default:
 384       assert(false, "surprise");
 385       return "??";
 386   }
 387 }
 388 
 389 // Probe OS for multipage support.
 390 // Will fill the global g_multipage_support structure.
 391 // Must be called before calling os::large_page_init().
 392 static void query_multipage_support() {
 393 
 394   guarantee(g_multipage_support.pagesize == -1,
 395             "do not call twice");
 396 
 397   g_multipage_support.pagesize = ::sysconf(_SC_PAGESIZE);
 398 
 399   // This really would surprise me.
 400   assert(g_multipage_support.pagesize == 4*K, "surprise!");
 401 
 402   // Query default data page size (default page size for C-Heap, pthread stacks and .bss).
 403   // Default data page size is defined either by linker options (-bdatapsize)
 404   // or by environment variable LDR_CNTRL (suboption DATAPSIZE). If none is given,
 405   // default should be 4K.
 406   {
 407     void* p = ::malloc(16*M);
 408     g_multipage_support.datapsize = os::Aix::query_pagesize(p);
 409     ::free(p);
 410   }
 411 
 412   // Query default shm page size (LDR_CNTRL SHMPSIZE).
 413   // Note that this is pure curiosity. We do not rely on default page size but set
 414   // our own page size after allocated.
 415   {
 416     const int shmid = ::shmget(IPC_PRIVATE, 1, IPC_CREAT | S_IRUSR | S_IWUSR);
 417     guarantee(shmid != -1, "shmget failed");
 418     void* p = ::shmat(shmid, NULL, 0);
 419     ::shmctl(shmid, IPC_RMID, NULL);
 420     guarantee(p != (void*) -1, "shmat failed");
 421     g_multipage_support.shmpsize = os::Aix::query_pagesize(p);
 422     ::shmdt(p);
 423   }
 424 
 425   // Before querying the stack page size, make sure we are not running as primordial
 426   // thread (because primordial thread's stack may have different page size than
 427   // pthread thread stacks). Running a VM on the primordial thread won't work for a
 428   // number of reasons so we may just as well guarantee it here.
 429   guarantee0(!os::is_primordial_thread());
 430 
 431   // Query pthread stack page size. Should be the same as data page size because
 432   // pthread stacks are allocated from C-Heap.
 433   {
 434     int dummy = 0;
 435     g_multipage_support.pthr_stack_pagesize = os::Aix::query_pagesize(&dummy);
 436   }
 437 
 438   // Query default text page size (LDR_CNTRL TEXTPSIZE).
 439   {
 440     address any_function =
 441       resolve_function_descriptor_to_code_pointer((address)describe_pagesize);
 442     g_multipage_support.textpsize = os::Aix::query_pagesize(any_function);
 443   }
 444 
 445   // Now probe for support of 64K pages and 16M pages.
 446 
 447   // Before OS/400 V6R1, there is no support for pages other than 4K.
 448   if (os::Aix::on_pase_V5R4_or_older()) {
 449     trcVerbose("OS/400 < V6R1 - no large page support.");
 450     g_multipage_support.error = ERROR_MP_OS_TOO_OLD;
 451     goto query_multipage_support_end;
 452   }
 453 
 454   // Now check which page sizes the OS claims it supports, and of those, which actually can be used.
 455   {
 456     const int MAX_PAGE_SIZES = 4;
 457     psize_t sizes[MAX_PAGE_SIZES];
 458     const int num_psizes = checked_vmgetinfo(sizes, VMINFO_GETPSIZES, MAX_PAGE_SIZES);
 459     if (num_psizes == -1) {
 460       trcVerbose("vmgetinfo(VMINFO_GETPSIZES) failed (errno: %d)", errno);
 461       trcVerbose("disabling multipage support.");
 462       g_multipage_support.error = ERROR_MP_VMGETINFO_FAILED;
 463       goto query_multipage_support_end;
 464     }
 465     guarantee(num_psizes > 0, "vmgetinfo(.., VMINFO_GETPSIZES, ...) failed.");
 466     assert(num_psizes <= MAX_PAGE_SIZES, "Surprise! more than 4 page sizes?");
 467     trcVerbose("vmgetinfo(.., VMINFO_GETPSIZES, ...) returns %d supported page sizes: ", num_psizes);
 468     for (int i = 0; i < num_psizes; i ++) {
 469       trcVerbose(" %s ", describe_pagesize(sizes[i]));
 470     }
 471 
 472     // Can we use 64K, 16M pages?
 473     for (int i = 0; i < num_psizes; i ++) {
 474       const size_t pagesize = sizes[i];
 475       if (pagesize != 64*K && pagesize != 16*M) {
 476         continue;
 477       }
 478       bool can_use = false;
 479       trcVerbose("Probing support for %s pages...", describe_pagesize(pagesize));
 480       const int shmid = ::shmget(IPC_PRIVATE, pagesize,
 481         IPC_CREAT | S_IRUSR | S_IWUSR);
 482       guarantee0(shmid != -1); // Should always work.
 483       // Try to set pagesize.
 484       struct shmid_ds shm_buf = { 0 };
 485       shm_buf.shm_pagesize = pagesize;
 486       if (::shmctl(shmid, SHM_PAGESIZE, &shm_buf) != 0) {
 487         const int en = errno;
 488         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 489         trcVerbose("shmctl(SHM_PAGESIZE) failed with errno=%n",
 490           errno);
 491       } else {
 492         // Attach and double check pageisze.
 493         void* p = ::shmat(shmid, NULL, 0);
 494         ::shmctl(shmid, IPC_RMID, NULL); // As early as possible!
 495         guarantee0(p != (void*) -1); // Should always work.
 496         const size_t real_pagesize = os::Aix::query_pagesize(p);
 497         if (real_pagesize != pagesize) {
 498           trcVerbose("real page size (0x%llX) differs.", real_pagesize);
 499         } else {
 500           can_use = true;
 501         }
 502         ::shmdt(p);
 503       }
 504       trcVerbose("Can use: %s", (can_use ? "yes" : "no"));
 505       if (pagesize == 64*K) {
 506         g_multipage_support.can_use_64K_pages = can_use;
 507       } else if (pagesize == 16*M) {
 508         g_multipage_support.can_use_16M_pages = can_use;
 509       }
 510     }
 511 
 512   } // end: check which pages can be used for shared memory
 513 
 514 query_multipage_support_end:
 515 
 516   trcVerbose("base page size (sysconf _SC_PAGESIZE): %s",
 517       describe_pagesize(g_multipage_support.pagesize));
 518   trcVerbose("Data page size (C-Heap, bss, etc): %s",
 519       describe_pagesize(g_multipage_support.datapsize));
 520   trcVerbose("Text page size: %s",
 521       describe_pagesize(g_multipage_support.textpsize));
 522   trcVerbose("Thread stack page size (pthread): %s",
 523       describe_pagesize(g_multipage_support.pthr_stack_pagesize));
 524   trcVerbose("Default shared memory page size: %s",
 525       describe_pagesize(g_multipage_support.shmpsize));
 526   trcVerbose("Can use 64K pages dynamically with shared meory: %s",
 527       (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
 528   trcVerbose("Can use 16M pages dynamically with shared memory: %s",
 529       (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
 530   trcVerbose("Multipage error details: %d",
 531       g_multipage_support.error);
 532 
 533   // sanity checks
 534   assert0(g_multipage_support.pagesize == 4*K);
 535   assert0(g_multipage_support.datapsize == 4*K || g_multipage_support.datapsize == 64*K);
 536   assert0(g_multipage_support.textpsize == 4*K || g_multipage_support.textpsize == 64*K);
 537   assert0(g_multipage_support.pthr_stack_pagesize == g_multipage_support.datapsize);
 538   assert0(g_multipage_support.shmpsize == 4*K || g_multipage_support.shmpsize == 64*K);
 539 
 540 }
 541 
 542 void os::init_system_properties_values() {
 543 
 544 #define DEFAULT_LIBPATH "/lib:/usr/lib"
 545 #define EXTENSIONS_DIR  "/lib/ext"
 546 
 547   // Buffer that fits several sprintfs.
 548   // Note that the space for the trailing null is provided
 549   // by the nulls included by the sizeof operator.
 550   const size_t bufsize =
 551     MAX2((size_t)MAXPATHLEN,  // For dll_dir & friends.
 552          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR)); // extensions dir
 553   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 554 
 555   // sysclasspath, java_home, dll_dir
 556   {
 557     char *pslash;
 558     os::jvm_path(buf, bufsize);
 559 
 560     // Found the full path to libjvm.so.
 561     // Now cut the path to <java_home>/jre if we can.
 562     pslash = strrchr(buf, '/');
 563     if (pslash != NULL) {
 564       *pslash = '\0';            // Get rid of /libjvm.so.
 565     }
 566     pslash = strrchr(buf, '/');
 567     if (pslash != NULL) {
 568       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 569     }
 570     Arguments::set_dll_dir(buf);
 571 
 572     if (pslash != NULL) {
 573       pslash = strrchr(buf, '/');
 574       if (pslash != NULL) {
 575         *pslash = '\0';        // Get rid of /lib.
 576       }
 577     }
 578     Arguments::set_java_home(buf);
 579     set_boot_path('/', ':');
 580   }
 581 
 582   // Where to look for native libraries.
 583 
 584   // On Aix we get the user setting of LIBPATH.
 585   // Eventually, all the library path setting will be done here.
 586   // Get the user setting of LIBPATH.
 587   const char *v = ::getenv("LIBPATH");
 588   const char *v_colon = ":";
 589   if (v == NULL) { v = ""; v_colon = ""; }
 590 
 591   // Concatenate user and invariant part of ld_library_path.
 592   // That's +1 for the colon and +1 for the trailing '\0'.
 593   char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, strlen(v) + 1 + sizeof(DEFAULT_LIBPATH) + 1, mtInternal);
 594   sprintf(ld_library_path, "%s%s" DEFAULT_LIBPATH, v, v_colon);
 595   Arguments::set_library_path(ld_library_path);
 596   FREE_C_HEAP_ARRAY(char, ld_library_path);
 597 
 598   // Extensions directories.
 599   sprintf(buf, "%s" EXTENSIONS_DIR, Arguments::get_java_home());
 600   Arguments::set_ext_dirs(buf);
 601 
 602   FREE_C_HEAP_ARRAY(char, buf);
 603 
 604 #undef DEFAULT_LIBPATH
 605 #undef EXTENSIONS_DIR
 606 }
 607 
 608 ////////////////////////////////////////////////////////////////////////////////
 609 // breakpoint support
 610 
 611 void os::breakpoint() {
 612   BREAKPOINT;
 613 }
 614 
 615 extern "C" void breakpoint() {
 616   // use debugger to set breakpoint here
 617 }
 618 
 619 ////////////////////////////////////////////////////////////////////////////////
 620 // signal support
 621 
 622 debug_only(static bool signal_sets_initialized = false);
 623 static sigset_t unblocked_sigs, vm_sigs;
 624 
 625 bool os::Aix::is_sig_ignored(int sig) {
 626   struct sigaction oact;
 627   sigaction(sig, (struct sigaction*)NULL, &oact);
 628   void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
 629     : CAST_FROM_FN_PTR(void*, oact.sa_handler);
 630   if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
 631     return true;
 632   } else {
 633     return false;
 634   }
 635 }
 636 
 637 void os::Aix::signal_sets_init() {
 638   // Should also have an assertion stating we are still single-threaded.
 639   assert(!signal_sets_initialized, "Already initialized");
 640   // Fill in signals that are necessarily unblocked for all threads in
 641   // the VM. Currently, we unblock the following signals:
 642   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 643   //                         by -Xrs (=ReduceSignalUsage));
 644   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 645   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 646   // the dispositions or masks wrt these signals.
 647   // Programs embedding the VM that want to use the above signals for their
 648   // own purposes must, at this time, use the "-Xrs" option to prevent
 649   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 650   // (See bug 4345157, and other related bugs).
 651   // In reality, though, unblocking these signals is really a nop, since
 652   // these signals are not blocked by default.
 653   sigemptyset(&unblocked_sigs);
 654   sigaddset(&unblocked_sigs, SIGILL);
 655   sigaddset(&unblocked_sigs, SIGSEGV);
 656   sigaddset(&unblocked_sigs, SIGBUS);
 657   sigaddset(&unblocked_sigs, SIGFPE);
 658   sigaddset(&unblocked_sigs, SIGTRAP);
 659   sigaddset(&unblocked_sigs, SR_signum);
 660 
 661   if (!ReduceSignalUsage) {
 662    if (!os::Aix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 663      sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 664    }
 665    if (!os::Aix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 666      sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 667    }
 668    if (!os::Aix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 669      sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 670    }
 671   }
 672   // Fill in signals that are blocked by all but the VM thread.
 673   sigemptyset(&vm_sigs);
 674   if (!ReduceSignalUsage)
 675     sigaddset(&vm_sigs, BREAK_SIGNAL);
 676   debug_only(signal_sets_initialized = true);
 677 }
 678 
 679 // These are signals that are unblocked while a thread is running Java.
 680 // (For some reason, they get blocked by default.)
 681 sigset_t* os::Aix::unblocked_signals() {
 682   assert(signal_sets_initialized, "Not initialized");
 683   return &unblocked_sigs;
 684 }
 685 
 686 // These are the signals that are blocked while a (non-VM) thread is
 687 // running Java. Only the VM thread handles these signals.
 688 sigset_t* os::Aix::vm_signals() {
 689   assert(signal_sets_initialized, "Not initialized");
 690   return &vm_sigs;
 691 }
 692 
 693 void os::Aix::hotspot_sigmask(Thread* thread) {
 694 
 695   //Save caller's signal mask before setting VM signal mask
 696   sigset_t caller_sigmask;
 697   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 698 
 699   OSThread* osthread = thread->osthread();
 700   osthread->set_caller_sigmask(caller_sigmask);
 701 
 702   pthread_sigmask(SIG_UNBLOCK, os::Aix::unblocked_signals(), NULL);
 703 
 704   if (!ReduceSignalUsage) {
 705     if (thread->is_VM_thread()) {
 706       // Only the VM thread handles BREAK_SIGNAL ...
 707       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 708     } else {
 709       // ... all other threads block BREAK_SIGNAL
 710       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 711     }
 712   }
 713 }
 714 
 715 // retrieve memory information.
 716 // Returns false if something went wrong;
 717 // content of pmi undefined in this case.
 718 bool os::Aix::get_meminfo(meminfo_t* pmi) {
 719 
 720   assert(pmi, "get_meminfo: invalid parameter");
 721 
 722   memset(pmi, 0, sizeof(meminfo_t));
 723 
 724   if (os::Aix::on_pase()) {
 725     // On PASE, use the libo4 porting library.
 726 
 727     unsigned long long virt_total = 0;
 728     unsigned long long real_total = 0;
 729     unsigned long long real_free = 0;
 730     unsigned long long pgsp_total = 0;
 731     unsigned long long pgsp_free = 0;
 732     if (libo4::get_memory_info(&virt_total, &real_total, &real_free, &pgsp_total, &pgsp_free)) {
 733       pmi->virt_total = virt_total;
 734       pmi->real_total = real_total;
 735       pmi->real_free = real_free;
 736       pmi->pgsp_total = pgsp_total;
 737       pmi->pgsp_free = pgsp_free;
 738       return true;
 739     }
 740     return false;
 741 
 742   } else {
 743 
 744     // On AIX, I use the (dynamically loaded) perfstat library to retrieve memory statistics
 745     // See:
 746     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 747     //        ?topic=/com.ibm.aix.basetechref/doc/basetrf1/perfstat_memtot.htm
 748     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 749     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 750 
 751     perfstat_memory_total_t psmt;
 752     memset (&psmt, '\0', sizeof(psmt));
 753     const int rc = libperfstat::perfstat_memory_total(NULL, &psmt, sizeof(psmt), 1);
 754     if (rc == -1) {
 755       trcVerbose("perfstat_memory_total() failed (errno=%d)", errno);
 756       assert(0, "perfstat_memory_total() failed");
 757       return false;
 758     }
 759 
 760     assert(rc == 1, "perfstat_memory_total() - weird return code");
 761 
 762     // excerpt from
 763     // http://publib.boulder.ibm.com/infocenter/systems/index.jsp
 764     //        ?topic=/com.ibm.aix.files/doc/aixfiles/libperfstat.h.htm
 765     // The fields of perfstat_memory_total_t:
 766     // u_longlong_t virt_total         Total virtual memory (in 4 KB pages).
 767     // u_longlong_t real_total         Total real memory (in 4 KB pages).
 768     // u_longlong_t real_free          Free real memory (in 4 KB pages).
 769     // u_longlong_t pgsp_total         Total paging space (in 4 KB pages).
 770     // u_longlong_t pgsp_free          Free paging space (in 4 KB pages).
 771 
 772     pmi->virt_total = psmt.virt_total * 4096;
 773     pmi->real_total = psmt.real_total * 4096;
 774     pmi->real_free = psmt.real_free * 4096;
 775     pmi->pgsp_total = psmt.pgsp_total * 4096;
 776     pmi->pgsp_free = psmt.pgsp_free * 4096;
 777 
 778     return true;
 779 
 780   }
 781 } // end os::Aix::get_meminfo
 782 
 783 //////////////////////////////////////////////////////////////////////////////
 784 // create new thread
 785 
 786 // Thread start routine for all newly created threads
 787 static void *thread_native_entry(Thread *thread) {
 788 
 789   // find out my own stack dimensions
 790   {
 791     // actually, this should do exactly the same as thread->record_stack_base_and_size...
 792     thread->set_stack_base(os::current_stack_base());
 793     thread->set_stack_size(os::current_stack_size());
 794   }
 795 
 796   const pthread_t pthread_id = ::pthread_self();
 797   const tid_t kernel_thread_id = ::thread_self();
 798 
 799   LogTarget(Info, os, thread) lt;
 800   if (lt.is_enabled()) {
 801     address low_address = thread->stack_end();
 802     address high_address = thread->stack_base();
 803     lt.print("Thread is alive (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT
 804              ", stack [" PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "k using %uk pages)).",
 805              os::current_thread_id(), (uintx) kernel_thread_id, low_address, high_address,
 806              (high_address - low_address) / K, os::Aix::query_pagesize(low_address) / K);
 807   }
 808 
 809   // Normally, pthread stacks on AIX live in the data segment (are allocated with malloc()
 810   // by the pthread library). In rare cases, this may not be the case, e.g. when third-party
 811   // tools hook pthread_create(). In this case, we may run into problems establishing
 812   // guard pages on those stacks, because the stacks may reside in memory which is not
 813   // protectable (shmated).
 814   if (thread->stack_base() > ::sbrk(0)) {
 815     log_warning(os, thread)("Thread stack not in data segment.");
 816   }
 817 
 818   // Try to randomize the cache line index of hot stack frames.
 819   // This helps when threads of the same stack traces evict each other's
 820   // cache lines. The threads can be either from the same JVM instance, or
 821   // from different JVM instances. The benefit is especially true for
 822   // processors with hyperthreading technology.
 823 
 824   static int counter = 0;
 825   int pid = os::current_process_id();
 826   alloca(((pid ^ counter++) & 7) * 128);
 827 
 828   thread->initialize_thread_current();
 829 
 830   OSThread* osthread = thread->osthread();
 831 
 832   // Thread_id is pthread id.
 833   osthread->set_thread_id(pthread_id);
 834 
 835   // .. but keep kernel thread id too for diagnostics
 836   osthread->set_kernel_thread_id(kernel_thread_id);
 837 
 838   // Initialize signal mask for this thread.
 839   os::Aix::hotspot_sigmask(thread);
 840 
 841   // Initialize floating point control register.
 842   os::Aix::init_thread_fpu_state();
 843 
 844   assert(osthread->get_state() == RUNNABLE, "invalid os thread state");
 845 
 846   // Call one more level start routine.
 847   thread->run();
 848 
 849   log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
 850     os::current_thread_id(), (uintx) kernel_thread_id);
 851 
 852   // If a thread has not deleted itself ("delete this") as part of its
 853   // termination sequence, we have to ensure thread-local-storage is
 854   // cleared before we actually terminate. No threads should ever be
 855   // deleted asynchronously with respect to their termination.
 856   if (Thread::current_or_null_safe() != NULL) {
 857     assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
 858     thread->clear_thread_current();
 859   }
 860 
 861   return 0;
 862 }
 863 
 864 bool os::create_thread(Thread* thread, ThreadType thr_type,
 865                        size_t req_stack_size) {
 866 
 867   assert(thread->osthread() == NULL, "caller responsible");
 868 
 869   // Allocate the OSThread object.
 870   OSThread* osthread = new OSThread(NULL, NULL);
 871   if (osthread == NULL) {
 872     return false;
 873   }
 874 
 875   // Set the correct thread state.
 876   osthread->set_thread_type(thr_type);
 877 
 878   // Initial state is ALLOCATED but not INITIALIZED
 879   osthread->set_state(ALLOCATED);
 880 
 881   thread->set_osthread(osthread);
 882 
 883   // Init thread attributes.
 884   pthread_attr_t attr;
 885   pthread_attr_init(&attr);
 886   guarantee(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0, "???");
 887 
 888   // Make sure we run in 1:1 kernel-user-thread mode.
 889   if (os::Aix::on_aix()) {
 890     guarantee(pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM) == 0, "???");
 891     guarantee(pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED) == 0, "???");
 892   }
 893 
 894   // Start in suspended state, and in os::thread_start, wake the thread up.
 895   guarantee(pthread_attr_setsuspendstate_np(&attr, PTHREAD_CREATE_SUSPENDED_NP) == 0, "???");
 896 
 897   // Calculate stack size if it's not specified by caller.
 898   size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
 899 
 900   // JDK-8187028: It was observed that on some configurations (4K backed thread stacks)
 901   // the real thread stack size may be smaller than the requested stack size, by as much as 64K.
 902   // This very much looks like a pthread lib error. As a workaround, increase the stack size
 903   // by 64K for small thread stacks (arbitrarily choosen to be < 4MB)
 904   if (stack_size < 4096 * K) {
 905     stack_size += 64 * K;
 906   }
 907 
 908   // On Aix, pthread_attr_setstacksize fails with huge values and leaves the
 909   // thread size in attr unchanged. If this is the minimal stack size as set
 910   // by pthread_attr_init this leads to crashes after thread creation. E.g. the
 911   // guard pages might not fit on the tiny stack created.
 912   int ret = pthread_attr_setstacksize(&attr, stack_size);
 913   if (ret != 0) {
 914     log_warning(os, thread)("The thread stack size specified is invalid: " SIZE_FORMAT "k",
 915                             stack_size / K);
 916   }
 917 
 918   // Save some cycles and a page by disabling OS guard pages where we have our own
 919   // VM guard pages (in java threads). For other threads, keep system default guard
 920   // pages in place.
 921   if (thr_type == java_thread || thr_type == compiler_thread) {
 922     ret = pthread_attr_setguardsize(&attr, 0);
 923   }
 924 
 925   pthread_t tid = 0;
 926   if (ret == 0) {
 927     ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
 928   }
 929 
 930   if (ret == 0) {
 931     char buf[64];
 932     log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
 933       (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 934   } else {
 935     char buf[64];
 936     log_warning(os, thread)("Failed to start thread - pthread_create failed (%d=%s) for attributes: %s.",
 937       ret, os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
 938   }
 939 
 940   pthread_attr_destroy(&attr);
 941 
 942   if (ret != 0) {
 943     // Need to clean up stuff we've allocated so far.
 944     thread->set_osthread(NULL);
 945     delete osthread;
 946     return false;
 947   }
 948 
 949   // OSThread::thread_id is the pthread id.
 950   osthread->set_thread_id(tid);
 951 
 952   return true;
 953 }
 954 
 955 /////////////////////////////////////////////////////////////////////////////
 956 // attach existing thread
 957 
 958 // bootstrap the main thread
 959 bool os::create_main_thread(JavaThread* thread) {
 960   assert(os::Aix::_main_thread == pthread_self(), "should be called inside main thread");
 961   return create_attached_thread(thread);
 962 }
 963 
 964 bool os::create_attached_thread(JavaThread* thread) {
 965 #ifdef ASSERT
 966     thread->verify_not_published();
 967 #endif
 968 
 969   // Allocate the OSThread object
 970   OSThread* osthread = new OSThread(NULL, NULL);
 971 
 972   if (osthread == NULL) {
 973     return false;
 974   }
 975 
 976   const pthread_t pthread_id = ::pthread_self();
 977   const tid_t kernel_thread_id = ::thread_self();
 978 
 979   // OSThread::thread_id is the pthread id.
 980   osthread->set_thread_id(pthread_id);
 981 
 982   // .. but keep kernel thread id too for diagnostics
 983   osthread->set_kernel_thread_id(kernel_thread_id);
 984 
 985   // initialize floating point control register
 986   os::Aix::init_thread_fpu_state();
 987 
 988   // Initial thread state is RUNNABLE
 989   osthread->set_state(RUNNABLE);
 990 
 991   thread->set_osthread(osthread);
 992 
 993   if (UseNUMA) {
 994     int lgrp_id = os::numa_get_group_id();
 995     if (lgrp_id != -1) {
 996       thread->set_lgrp_id(lgrp_id);
 997     }
 998   }
 999 
1000   // initialize signal mask for this thread
1001   // and save the caller's signal mask
1002   os::Aix::hotspot_sigmask(thread);
1003 
1004   log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", kernel thread id: " UINTX_FORMAT ").",
1005     os::current_thread_id(), (uintx) kernel_thread_id);
1006 
1007   return true;
1008 }
1009 
1010 void os::pd_start_thread(Thread* thread) {
1011   int status = pthread_continue_np(thread->osthread()->pthread_id());
1012   assert(status == 0, "thr_continue failed");
1013 }
1014 
1015 // Free OS resources related to the OSThread
1016 void os::free_thread(OSThread* osthread) {
1017   assert(osthread != NULL, "osthread not set");
1018 
1019   // We are told to free resources of the argument thread,
1020   // but we can only really operate on the current thread.
1021   assert(Thread::current()->osthread() == osthread,
1022          "os::free_thread but not current thread");
1023 
1024   // Restore caller's signal mask
1025   sigset_t sigmask = osthread->caller_sigmask();
1026   pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1027 
1028   delete osthread;
1029 }
1030 
1031 ////////////////////////////////////////////////////////////////////////////////
1032 // time support
1033 
1034 // Time since start-up in seconds to a fine granularity.
1035 // Used by VMSelfDestructTimer and the MemProfiler.
1036 double os::elapsedTime() {
1037   return (double)(os::elapsed_counter()) * 0.000001;
1038 }
1039 
1040 jlong os::elapsed_counter() {
1041   timeval time;
1042   int status = gettimeofday(&time, NULL);
1043   return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1044 }
1045 
1046 jlong os::elapsed_frequency() {
1047   return (1000 * 1000);
1048 }
1049 
1050 bool os::supports_vtime() { return true; }
1051 bool os::enable_vtime()   { return false; }
1052 bool os::vtime_enabled()  { return false; }
1053 
1054 double os::elapsedVTime() {
1055   struct rusage usage;
1056   int retval = getrusage(RUSAGE_THREAD, &usage);
1057   if (retval == 0) {
1058     return usage.ru_utime.tv_sec + usage.ru_stime.tv_sec + (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000.0 * 1000);
1059   } else {
1060     // better than nothing, but not much
1061     return elapsedTime();
1062   }
1063 }
1064 
1065 jlong os::javaTimeMillis() {
1066   timeval time;
1067   int status = gettimeofday(&time, NULL);
1068   assert(status != -1, "aix error at gettimeofday()");
1069   return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1070 }
1071 
1072 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1073   timeval time;
1074   int status = gettimeofday(&time, NULL);
1075   assert(status != -1, "aix error at gettimeofday()");
1076   seconds = jlong(time.tv_sec);
1077   nanos = jlong(time.tv_usec) * 1000;
1078 }
1079 
1080 // We use mread_real_time here.
1081 // On AIX: If the CPU has a time register, the result will be RTC_POWER and
1082 // it has to be converted to real time. AIX documentations suggests to do
1083 // this unconditionally, so we do it.
1084 //
1085 // See: https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.basetrf2/read_real_time.htm
1086 //
1087 // On PASE: mread_real_time will always return RTC_POWER_PC data, so no
1088 // conversion is necessary. However, mread_real_time will not return
1089 // monotonic results but merely matches read_real_time. So we need a tweak
1090 // to ensure monotonic results.
1091 //
1092 // For PASE no public documentation exists, just word by IBM
1093 jlong os::javaTimeNanos() {
1094   timebasestruct_t time;
1095   int rc = mread_real_time(&time, TIMEBASE_SZ);
1096   if (os::Aix::on_pase()) {
1097     assert(rc == RTC_POWER, "expected time format RTC_POWER from mread_real_time in PASE");
1098     jlong now = jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1099     jlong prev = max_real_time;
1100     if (now <= prev) {
1101       return prev;   // same or retrograde time;
1102     }
1103     jlong obsv = Atomic::cmpxchg(now, &max_real_time, prev);
1104     assert(obsv >= prev, "invariant");   // Monotonicity
1105     // If the CAS succeeded then we're done and return "now".
1106     // If the CAS failed and the observed value "obsv" is >= now then
1107     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1108     // some other thread raced this thread and installed a new value, in which case
1109     // we could either (a) retry the entire operation, (b) retry trying to install now
1110     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1111     // we might discard a higher "now" value in deference to a slightly lower but freshly
1112     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1113     // to (a) or (b) -- and greatly reduces coherence traffic.
1114     // We might also condition (c) on the magnitude of the delta between obsv and now.
1115     // Avoiding excessive CAS operations to hot RW locations is critical.
1116     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1117     return (prev == obsv) ? now : obsv;
1118   } else {
1119     if (rc != RTC_POWER) {
1120       rc = time_base_to_time(&time, TIMEBASE_SZ);
1121       assert(rc != -1, "error calling time_base_to_time()");
1122     }
1123     return jlong(time.tb_high) * NANOSECS_PER_SEC + jlong(time.tb_low);
1124   }
1125 }
1126 
1127 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1128   info_ptr->max_value = ALL_64_BITS;
1129   // mread_real_time() is monotonic (see 'os::javaTimeNanos()')
1130   info_ptr->may_skip_backward = false;
1131   info_ptr->may_skip_forward = false;
1132   info_ptr->kind = JVMTI_TIMER_ELAPSED;    // elapsed not CPU time
1133 }
1134 
1135 // Return the real, user, and system times in seconds from an
1136 // arbitrary fixed point in the past.
1137 bool os::getTimesSecs(double* process_real_time,
1138                       double* process_user_time,
1139                       double* process_system_time) {
1140   struct tms ticks;
1141   clock_t real_ticks = times(&ticks);
1142 
1143   if (real_ticks == (clock_t) (-1)) {
1144     return false;
1145   } else {
1146     double ticks_per_second = (double) clock_tics_per_sec;
1147     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1148     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1149     *process_real_time = ((double) real_ticks) / ticks_per_second;
1150 
1151     return true;
1152   }
1153 }
1154 
1155 char * os::local_time_string(char *buf, size_t buflen) {
1156   struct tm t;
1157   time_t long_time;
1158   time(&long_time);
1159   localtime_r(&long_time, &t);
1160   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1161                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1162                t.tm_hour, t.tm_min, t.tm_sec);
1163   return buf;
1164 }
1165 
1166 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1167   return localtime_r(clock, res);
1168 }
1169 
1170 ////////////////////////////////////////////////////////////////////////////////
1171 // runtime exit support
1172 
1173 // Note: os::shutdown() might be called very early during initialization, or
1174 // called from signal handler. Before adding something to os::shutdown(), make
1175 // sure it is async-safe and can handle partially initialized VM.
1176 void os::shutdown() {
1177 
1178   // allow PerfMemory to attempt cleanup of any persistent resources
1179   perfMemory_exit();
1180 
1181   // needs to remove object in file system
1182   AttachListener::abort();
1183 
1184   // flush buffered output, finish log files
1185   ostream_abort();
1186 
1187   // Check for abort hook
1188   abort_hook_t abort_hook = Arguments::abort_hook();
1189   if (abort_hook != NULL) {
1190     abort_hook();
1191   }
1192 }
1193 
1194 // Note: os::abort() might be called very early during initialization, or
1195 // called from signal handler. Before adding something to os::abort(), make
1196 // sure it is async-safe and can handle partially initialized VM.
1197 void os::abort(bool dump_core, void* siginfo, const void* context) {
1198   os::shutdown();
1199   if (dump_core) {
1200 #ifndef PRODUCT
1201     fdStream out(defaultStream::output_fd());
1202     out.print_raw("Current thread is ");
1203     char buf[16];
1204     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1205     out.print_raw_cr(buf);
1206     out.print_raw_cr("Dumping core ...");
1207 #endif
1208     ::abort(); // dump core
1209   }
1210 
1211   ::exit(1);
1212 }
1213 
1214 // Die immediately, no exit hook, no abort hook, no cleanup.
1215 void os::die() {
1216   ::abort();
1217 }
1218 
1219 // This method is a copy of JDK's sysGetLastErrorString
1220 // from src/solaris/hpi/src/system_md.c
1221 
1222 size_t os::lasterror(char *buf, size_t len) {
1223   if (errno == 0) return 0;
1224 
1225   const char *s = os::strerror(errno);
1226   size_t n = ::strlen(s);
1227   if (n >= len) {
1228     n = len - 1;
1229   }
1230   ::strncpy(buf, s, n);
1231   buf[n] = '\0';
1232   return n;
1233 }
1234 
1235 intx os::current_thread_id() {
1236   return (intx)pthread_self();
1237 }
1238 
1239 int os::current_process_id() {
1240   return getpid();
1241 }
1242 
1243 // DLL functions
1244 
1245 const char* os::dll_file_extension() { return ".so"; }
1246 
1247 // This must be hard coded because it's the system's temporary
1248 // directory not the java application's temp directory, ala java.io.tmpdir.
1249 const char* os::get_temp_directory() { return "/tmp"; }
1250 
1251 // Check if addr is inside libjvm.so.
1252 bool os::address_is_in_vm(address addr) {
1253 
1254   // Input could be a real pc or a function pointer literal. The latter
1255   // would be a function descriptor residing in the data segment of a module.
1256   loaded_module_t lm;
1257   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL) {
1258     return lm.is_in_vm;
1259   } else if (LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
1260     return lm.is_in_vm;
1261   } else {
1262     return false;
1263   }
1264 
1265 }
1266 
1267 // Resolve an AIX function descriptor literal to a code pointer.
1268 // If the input is a valid code pointer to a text segment of a loaded module,
1269 //   it is returned unchanged.
1270 // If the input is a valid AIX function descriptor, it is resolved to the
1271 //   code entry point.
1272 // If the input is neither a valid function descriptor nor a valid code pointer,
1273 //   NULL is returned.
1274 static address resolve_function_descriptor_to_code_pointer(address p) {
1275 
1276   if (LoadedLibraries::find_for_text_address(p, NULL) != NULL) {
1277     // It is a real code pointer.
1278     return p;
1279   } else if (LoadedLibraries::find_for_data_address(p, NULL) != NULL) {
1280     // Pointer to data segment, potential function descriptor.
1281     address code_entry = (address)(((FunctionDescriptor*)p)->entry());
1282     if (LoadedLibraries::find_for_text_address(code_entry, NULL) != NULL) {
1283       // It is a function descriptor.
1284       return code_entry;
1285     }
1286   }
1287 
1288   return NULL;
1289 }
1290 
1291 bool os::dll_address_to_function_name(address addr, char *buf,
1292                                       int buflen, int *offset,
1293                                       bool demangle) {
1294   if (offset) {
1295     *offset = -1;
1296   }
1297   // Buf is not optional, but offset is optional.
1298   assert(buf != NULL, "sanity check");
1299   buf[0] = '\0';
1300 
1301   // Resolve function ptr literals first.
1302   addr = resolve_function_descriptor_to_code_pointer(addr);
1303   if (!addr) {
1304     return false;
1305   }
1306 
1307   return AixSymbols::get_function_name(addr, buf, buflen, offset, NULL, demangle);
1308 }
1309 
1310 bool os::dll_address_to_library_name(address addr, char* buf,
1311                                      int buflen, int* offset) {
1312   if (offset) {
1313     *offset = -1;
1314   }
1315   // Buf is not optional, but offset is optional.
1316   assert(buf != NULL, "sanity check");
1317   buf[0] = '\0';
1318 
1319   // Resolve function ptr literals first.
1320   addr = resolve_function_descriptor_to_code_pointer(addr);
1321   if (!addr) {
1322     return false;
1323   }
1324 
1325   return AixSymbols::get_module_name(addr, buf, buflen);
1326 }
1327 
1328 // Loads .dll/.so and in case of error it checks if .dll/.so was built
1329 // for the same architecture as Hotspot is running on.
1330 void *os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1331 
1332   if (ebuf && ebuflen > 0) {
1333     ebuf[0] = '\0';
1334     ebuf[ebuflen - 1] = '\0';
1335   }
1336 
1337   if (!filename || strlen(filename) == 0) {
1338     ::strncpy(ebuf, "dll_load: empty filename specified", ebuflen - 1);
1339     return NULL;
1340   }
1341 
1342   // RTLD_LAZY is currently not implemented. The dl is loaded immediately with all its dependants.
1343   void * result= ::dlopen(filename, RTLD_LAZY);
1344   if (result != NULL) {
1345     // Reload dll cache. Don't do this in signal handling.
1346     LoadedLibraries::reload();
1347     return result;
1348   } else {
1349     // error analysis when dlopen fails
1350     const char* const error_report = ::dlerror();
1351     if (error_report && ebuf && ebuflen > 0) {
1352       snprintf(ebuf, ebuflen - 1, "%s, LIBPATH=%s, LD_LIBRARY_PATH=%s : %s",
1353                filename, ::getenv("LIBPATH"), ::getenv("LD_LIBRARY_PATH"), error_report);
1354     }
1355   }
1356   return NULL;
1357 }
1358 
1359 void* os::dll_lookup(void* handle, const char* name) {
1360   void* res = dlsym(handle, name);
1361   return res;
1362 }
1363 
1364 void* os::get_default_process_handle() {
1365   return (void*)::dlopen(NULL, RTLD_LAZY);
1366 }
1367 
1368 void os::print_dll_info(outputStream *st) {
1369   st->print_cr("Dynamic libraries:");
1370   LoadedLibraries::print(st);
1371 }
1372 
1373 void os::get_summary_os_info(char* buf, size_t buflen) {
1374   // There might be something more readable than uname results for AIX.
1375   struct utsname name;
1376   uname(&name);
1377   snprintf(buf, buflen, "%s %s", name.release, name.version);
1378 }
1379 
1380 void os::print_os_info(outputStream* st) {
1381   st->print("OS:");
1382 
1383   st->print("uname:");
1384   struct utsname name;
1385   uname(&name);
1386   st->print(name.sysname); st->print(" ");
1387   st->print(name.nodename); st->print(" ");
1388   st->print(name.release); st->print(" ");
1389   st->print(name.version); st->print(" ");
1390   st->print(name.machine);
1391   st->cr();
1392 
1393   uint32_t ver = os::Aix::os_version();
1394   st->print_cr("AIX kernel version %u.%u.%u.%u",
1395                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
1396 
1397   os::Posix::print_rlimit_info(st);
1398 
1399   // load average
1400   st->print("load average:");
1401   double loadavg[3] = {-1.L, -1.L, -1.L};
1402   os::loadavg(loadavg, 3);
1403   st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1404   st->cr();
1405 
1406   // print wpar info
1407   libperfstat::wparinfo_t wi;
1408   if (libperfstat::get_wparinfo(&wi)) {
1409     st->print_cr("wpar info");
1410     st->print_cr("name: %s", wi.name);
1411     st->print_cr("id:   %d", wi.wpar_id);
1412     st->print_cr("type: %s", (wi.app_wpar ? "application" : "system"));
1413   }
1414 
1415   // print partition info
1416   libperfstat::partitioninfo_t pi;
1417   if (libperfstat::get_partitioninfo(&pi)) {
1418     st->print_cr("partition info");
1419     st->print_cr(" name: %s", pi.name);
1420   }
1421 
1422 }
1423 
1424 void os::print_memory_info(outputStream* st) {
1425 
1426   st->print_cr("Memory:");
1427 
1428   st->print_cr("  Base page size (sysconf _SC_PAGESIZE):  %s",
1429     describe_pagesize(g_multipage_support.pagesize));
1430   st->print_cr("  Data page size (C-Heap, bss, etc):      %s",
1431     describe_pagesize(g_multipage_support.datapsize));
1432   st->print_cr("  Text page size:                         %s",
1433     describe_pagesize(g_multipage_support.textpsize));
1434   st->print_cr("  Thread stack page size (pthread):       %s",
1435     describe_pagesize(g_multipage_support.pthr_stack_pagesize));
1436   st->print_cr("  Default shared memory page size:        %s",
1437     describe_pagesize(g_multipage_support.shmpsize));
1438   st->print_cr("  Can use 64K pages dynamically with shared meory:  %s",
1439     (g_multipage_support.can_use_64K_pages ? "yes" :"no"));
1440   st->print_cr("  Can use 16M pages dynamically with shared memory: %s",
1441     (g_multipage_support.can_use_16M_pages ? "yes" :"no"));
1442   st->print_cr("  Multipage error: %d",
1443     g_multipage_support.error);
1444   st->cr();
1445   st->print_cr("  os::vm_page_size:       %s", describe_pagesize(os::vm_page_size()));
1446 
1447   // print out LDR_CNTRL because it affects the default page sizes
1448   const char* const ldr_cntrl = ::getenv("LDR_CNTRL");
1449   st->print_cr("  LDR_CNTRL=%s.", ldr_cntrl ? ldr_cntrl : "<unset>");
1450 
1451   // Print out EXTSHM because it is an unsupported setting.
1452   const char* const extshm = ::getenv("EXTSHM");
1453   st->print_cr("  EXTSHM=%s.", extshm ? extshm : "<unset>");
1454   if ( (strcmp(extshm, "on") == 0) || (strcmp(extshm, "ON") == 0) ) {
1455     st->print_cr("  *** Unsupported! Please remove EXTSHM from your environment! ***");
1456   }
1457 
1458   // Print out AIXTHREAD_GUARDPAGES because it affects the size of pthread stacks.
1459   const char* const aixthread_guardpages = ::getenv("AIXTHREAD_GUARDPAGES");
1460   st->print_cr("  AIXTHREAD_GUARDPAGES=%s.",
1461       aixthread_guardpages ? aixthread_guardpages : "<unset>");
1462   st->cr();
1463 
1464   os::Aix::meminfo_t mi;
1465   if (os::Aix::get_meminfo(&mi)) {
1466     if (os::Aix::on_aix()) {
1467       st->print_cr("physical total : " SIZE_FORMAT, mi.real_total);
1468       st->print_cr("physical free  : " SIZE_FORMAT, mi.real_free);
1469       st->print_cr("swap total     : " SIZE_FORMAT, mi.pgsp_total);
1470       st->print_cr("swap free      : " SIZE_FORMAT, mi.pgsp_free);
1471     } else {
1472       // PASE - Numbers are result of QWCRSSTS; they mean:
1473       // real_total: Sum of all system pools
1474       // real_free: always 0
1475       // pgsp_total: we take the size of the system ASP
1476       // pgsp_free: size of system ASP times percentage of system ASP unused
1477       st->print_cr("physical total     : " SIZE_FORMAT, mi.real_total);
1478       st->print_cr("system asp total   : " SIZE_FORMAT, mi.pgsp_total);
1479       st->print_cr("%% system asp used : %.2f",
1480         mi.pgsp_total ? (100.0f * (mi.pgsp_total - mi.pgsp_free) / mi.pgsp_total) : -1.0f);
1481     }
1482   }
1483   st->cr();
1484 
1485   // Print program break.
1486   st->print_cr("Program break at VM startup: " PTR_FORMAT ".", p2i(g_brk_at_startup));
1487   address brk_now = (address)::sbrk(0);
1488   if (brk_now != (address)-1) {
1489     st->print_cr("Program break now          : " PTR_FORMAT " (distance: " SIZE_FORMAT "K).",
1490                  p2i(brk_now), (size_t)((brk_now - g_brk_at_startup) / K));
1491   }
1492   st->print_cr("MaxExpectedDataSegmentSize    : " SIZE_FORMAT "K.", MaxExpectedDataSegmentSize / K);
1493   st->cr();
1494 
1495   // Print segments allocated with os::reserve_memory.
1496   st->print_cr("internal virtual memory regions used by vm:");
1497   vmembk_print_on(st);
1498 }
1499 
1500 // Get a string for the cpuinfo that is a summary of the cpu type
1501 void os::get_summary_cpu_info(char* buf, size_t buflen) {
1502   // read _system_configuration.version
1503   switch (_system_configuration.version) {
1504   case PV_8:
1505     strncpy(buf, "Power PC 8", buflen);
1506     break;
1507   case PV_7:
1508     strncpy(buf, "Power PC 7", buflen);
1509     break;
1510   case PV_6_1:
1511     strncpy(buf, "Power PC 6 DD1.x", buflen);
1512     break;
1513   case PV_6:
1514     strncpy(buf, "Power PC 6", buflen);
1515     break;
1516   case PV_5:
1517     strncpy(buf, "Power PC 5", buflen);
1518     break;
1519   case PV_5_2:
1520     strncpy(buf, "Power PC 5_2", buflen);
1521     break;
1522   case PV_5_3:
1523     strncpy(buf, "Power PC 5_3", buflen);
1524     break;
1525   case PV_5_Compat:
1526     strncpy(buf, "PV_5_Compat", buflen);
1527     break;
1528   case PV_6_Compat:
1529     strncpy(buf, "PV_6_Compat", buflen);
1530     break;
1531   case PV_7_Compat:
1532     strncpy(buf, "PV_7_Compat", buflen);
1533     break;
1534   case PV_8_Compat:
1535     strncpy(buf, "PV_8_Compat", buflen);
1536     break;
1537   default:
1538     strncpy(buf, "unknown", buflen);
1539   }
1540 }
1541 
1542 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
1543   // Nothing to do beyond of what os::print_cpu_info() does.
1544 }
1545 
1546 static void print_signal_handler(outputStream* st, int sig,
1547                                  char* buf, size_t buflen);
1548 
1549 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1550   st->print_cr("Signal Handlers:");
1551   print_signal_handler(st, SIGSEGV, buf, buflen);
1552   print_signal_handler(st, SIGBUS , buf, buflen);
1553   print_signal_handler(st, SIGFPE , buf, buflen);
1554   print_signal_handler(st, SIGPIPE, buf, buflen);
1555   print_signal_handler(st, SIGXFSZ, buf, buflen);
1556   print_signal_handler(st, SIGILL , buf, buflen);
1557   print_signal_handler(st, SR_signum, buf, buflen);
1558   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1559   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1560   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1561   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1562   print_signal_handler(st, SIGTRAP, buf, buflen);
1563   // We also want to know if someone else adds a SIGDANGER handler because
1564   // that will interfere with OOM killling.
1565   print_signal_handler(st, SIGDANGER, buf, buflen);
1566 }
1567 
1568 static char saved_jvm_path[MAXPATHLEN] = {0};
1569 
1570 // Find the full path to the current module, libjvm.so.
1571 void os::jvm_path(char *buf, jint buflen) {
1572   // Error checking.
1573   if (buflen < MAXPATHLEN) {
1574     assert(false, "must use a large-enough buffer");
1575     buf[0] = '\0';
1576     return;
1577   }
1578   // Lazy resolve the path to current module.
1579   if (saved_jvm_path[0] != 0) {
1580     strcpy(buf, saved_jvm_path);
1581     return;
1582   }
1583 
1584   Dl_info dlinfo;
1585   int ret = dladdr(CAST_FROM_FN_PTR(void *, os::jvm_path), &dlinfo);
1586   assert(ret != 0, "cannot locate libjvm");
1587   char* rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1588   assert(rp != NULL, "error in realpath(): maybe the 'path' argument is too long?");
1589 
1590   if (Arguments::sun_java_launcher_is_altjvm()) {
1591     // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
1592     // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
1593     // If "/jre/lib/" appears at the right place in the string, then
1594     // assume we are installed in a JDK and we're done. Otherwise, check
1595     // for a JAVA_HOME environment variable and fix up the path so it
1596     // looks like libjvm.so is installed there (append a fake suffix
1597     // hotspot/libjvm.so).
1598     const char *p = buf + strlen(buf) - 1;
1599     for (int count = 0; p > buf && count < 4; ++count) {
1600       for (--p; p > buf && *p != '/'; --p)
1601         /* empty */ ;
1602     }
1603 
1604     if (strncmp(p, "/jre/lib/", 9) != 0) {
1605       // Look for JAVA_HOME in the environment.
1606       char* java_home_var = ::getenv("JAVA_HOME");
1607       if (java_home_var != NULL && java_home_var[0] != 0) {
1608         char* jrelib_p;
1609         int len;
1610 
1611         // Check the current module name "libjvm.so".
1612         p = strrchr(buf, '/');
1613         if (p == NULL) {
1614           return;
1615         }
1616         assert(strstr(p, "/libjvm") == p, "invalid library name");
1617 
1618         rp = os::Posix::realpath(java_home_var, buf, buflen);
1619         if (rp == NULL) {
1620           return;
1621         }
1622 
1623         // determine if this is a legacy image or modules image
1624         // modules image doesn't have "jre" subdirectory
1625         len = strlen(buf);
1626         assert(len < buflen, "Ran out of buffer room");
1627         jrelib_p = buf + len;
1628         snprintf(jrelib_p, buflen-len, "/jre/lib");
1629         if (0 != access(buf, F_OK)) {
1630           snprintf(jrelib_p, buflen-len, "/lib");
1631         }
1632 
1633         if (0 == access(buf, F_OK)) {
1634           // Use current module name "libjvm.so"
1635           len = strlen(buf);
1636           snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
1637         } else {
1638           // Go back to path of .so
1639           rp = os::Posix::realpath((char *)dlinfo.dli_fname, buf, buflen);
1640           if (rp == NULL) {
1641             return;
1642           }
1643         }
1644       }
1645     }
1646   }
1647 
1648   strncpy(saved_jvm_path, buf, sizeof(saved_jvm_path));
1649   saved_jvm_path[sizeof(saved_jvm_path) - 1] = '\0';
1650 }
1651 
1652 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1653   // no prefix required, not even "_"
1654 }
1655 
1656 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1657   // no suffix required
1658 }
1659 
1660 ////////////////////////////////////////////////////////////////////////////////
1661 // sun.misc.Signal support
1662 
1663 static volatile jint sigint_count = 0;
1664 
1665 static void
1666 UserHandler(int sig, void *siginfo, void *context) {
1667   // 4511530 - sem_post is serialized and handled by the manager thread. When
1668   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1669   // don't want to flood the manager thread with sem_post requests.
1670   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1671     return;
1672 
1673   // Ctrl-C is pressed during error reporting, likely because the error
1674   // handler fails to abort. Let VM die immediately.
1675   if (sig == SIGINT && VMError::is_error_reported()) {
1676     os::die();
1677   }
1678 
1679   os::signal_notify(sig);
1680 }
1681 
1682 void* os::user_handler() {
1683   return CAST_FROM_FN_PTR(void*, UserHandler);
1684 }
1685 
1686 extern "C" {
1687   typedef void (*sa_handler_t)(int);
1688   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1689 }
1690 
1691 void* os::signal(int signal_number, void* handler) {
1692   struct sigaction sigAct, oldSigAct;
1693 
1694   sigfillset(&(sigAct.sa_mask));
1695 
1696   // Do not block out synchronous signals in the signal handler.
1697   // Blocking synchronous signals only makes sense if you can really
1698   // be sure that those signals won't happen during signal handling,
1699   // when the blocking applies. Normal signal handlers are lean and
1700   // do not cause signals. But our signal handlers tend to be "risky"
1701   // - secondary SIGSEGV, SIGILL, SIGBUS' may and do happen.
1702   // On AIX, PASE there was a case where a SIGSEGV happened, followed
1703   // by a SIGILL, which was blocked due to the signal mask. The process
1704   // just hung forever. Better to crash from a secondary signal than to hang.
1705   sigdelset(&(sigAct.sa_mask), SIGSEGV);
1706   sigdelset(&(sigAct.sa_mask), SIGBUS);
1707   sigdelset(&(sigAct.sa_mask), SIGILL);
1708   sigdelset(&(sigAct.sa_mask), SIGFPE);
1709   sigdelset(&(sigAct.sa_mask), SIGTRAP);
1710 
1711   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1712 
1713   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1714 
1715   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1716     // -1 means registration failed
1717     return (void *)-1;
1718   }
1719 
1720   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1721 }
1722 
1723 void os::signal_raise(int signal_number) {
1724   ::raise(signal_number);
1725 }
1726 
1727 //
1728 // The following code is moved from os.cpp for making this
1729 // code platform specific, which it is by its very nature.
1730 //
1731 
1732 // Will be modified when max signal is changed to be dynamic
1733 int os::sigexitnum_pd() {
1734   return NSIG;
1735 }
1736 
1737 // a counter for each possible signal value
1738 static volatile jint pending_signals[NSIG+1] = { 0 };
1739 
1740 // Wrapper functions for: sem_init(), sem_post(), sem_wait()
1741 // On AIX, we use sem_init(), sem_post(), sem_wait()
1742 // On Pase, we need to use msem_lock() and msem_unlock(), because Posix Semaphores
1743 // do not seem to work at all on PASE (unimplemented, will cause SIGILL).
1744 // Note that just using msem_.. APIs for both PASE and AIX is not an option either, as
1745 // on AIX, msem_..() calls are suspected of causing problems.
1746 static sem_t sig_sem;
1747 static msemaphore* p_sig_msem = 0;
1748 
1749 static void local_sem_init() {
1750   if (os::Aix::on_aix()) {
1751     int rc = ::sem_init(&sig_sem, 0, 0);
1752     guarantee(rc != -1, "sem_init failed");
1753   } else {
1754     // Memory semaphores must live in shared mem.
1755     guarantee0(p_sig_msem == NULL);
1756     p_sig_msem = (msemaphore*)os::reserve_memory(sizeof(msemaphore), NULL);
1757     guarantee(p_sig_msem, "Cannot allocate memory for memory semaphore");
1758     guarantee(::msem_init(p_sig_msem, 0) == p_sig_msem, "msem_init failed");
1759   }
1760 }
1761 
1762 static void local_sem_post() {
1763   static bool warn_only_once = false;
1764   if (os::Aix::on_aix()) {
1765     int rc = ::sem_post(&sig_sem);
1766     if (rc == -1 && !warn_only_once) {
1767       trcVerbose("sem_post failed (errno = %d, %s)", errno, os::errno_name(errno));
1768       warn_only_once = true;
1769     }
1770   } else {
1771     guarantee0(p_sig_msem != NULL);
1772     int rc = ::msem_unlock(p_sig_msem, 0);
1773     if (rc == -1 && !warn_only_once) {
1774       trcVerbose("msem_unlock failed (errno = %d, %s)", errno, os::errno_name(errno));
1775       warn_only_once = true;
1776     }
1777   }
1778 }
1779 
1780 static void local_sem_wait() {
1781   static bool warn_only_once = false;
1782   if (os::Aix::on_aix()) {
1783     int rc = ::sem_wait(&sig_sem);
1784     if (rc == -1 && !warn_only_once) {
1785       trcVerbose("sem_wait failed (errno = %d, %s)", errno, os::errno_name(errno));
1786       warn_only_once = true;
1787     }
1788   } else {
1789     guarantee0(p_sig_msem != NULL); // must init before use
1790     int rc = ::msem_lock(p_sig_msem, 0);
1791     if (rc == -1 && !warn_only_once) {
1792       trcVerbose("msem_lock failed (errno = %d, %s)", errno, os::errno_name(errno));
1793       warn_only_once = true;
1794     }
1795   }
1796 }
1797 
1798 void os::signal_init_pd() {
1799   // Initialize signal structures
1800   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
1801 
1802   // Initialize signal semaphore
1803   local_sem_init();
1804 }
1805 
1806 void os::signal_notify(int sig) {
1807   Atomic::inc(&pending_signals[sig]);
1808   local_sem_post();
1809 }
1810 
1811 static int check_pending_signals() {
1812   Atomic::store(0, &sigint_count);
1813   for (;;) {
1814     for (int i = 0; i < NSIG + 1; i++) {
1815       jint n = pending_signals[i];
1816       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
1817         return i;
1818       }
1819     }
1820     JavaThread *thread = JavaThread::current();
1821     ThreadBlockInVM tbivm(thread);
1822 
1823     bool threadIsSuspended;
1824     do {
1825       thread->set_suspend_equivalent();
1826       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1827 
1828       local_sem_wait();
1829 
1830       // were we externally suspended while we were waiting?
1831       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
1832       if (threadIsSuspended) {
1833         //
1834         // The semaphore has been incremented, but while we were waiting
1835         // another thread suspended us. We don't want to continue running
1836         // while suspended because that would surprise the thread that
1837         // suspended us.
1838         //
1839 
1840         local_sem_post();
1841 
1842         thread->java_suspend_self();
1843       }
1844     } while (threadIsSuspended);
1845   }
1846 }
1847 
1848 int os::signal_wait() {
1849   return check_pending_signals();
1850 }
1851 
1852 ////////////////////////////////////////////////////////////////////////////////
1853 // Virtual Memory
1854 
1855 // We need to keep small simple bookkeeping for os::reserve_memory and friends.
1856 
1857 #define VMEM_MAPPED  1
1858 #define VMEM_SHMATED 2
1859 
1860 struct vmembk_t {
1861   int type;         // 1 - mmap, 2 - shmat
1862   char* addr;
1863   size_t size;      // Real size, may be larger than usersize.
1864   size_t pagesize;  // page size of area
1865   vmembk_t* next;
1866 
1867   bool contains_addr(char* p) const {
1868     return p >= addr && p < (addr + size);
1869   }
1870 
1871   bool contains_range(char* p, size_t s) const {
1872     return contains_addr(p) && contains_addr(p + s - 1);
1873   }
1874 
1875   void print_on(outputStream* os) const {
1876     os->print("[" PTR_FORMAT " - " PTR_FORMAT "] (" UINTX_FORMAT
1877       " bytes, %d %s pages), %s",
1878       addr, addr + size - 1, size, size / pagesize, describe_pagesize(pagesize),
1879       (type == VMEM_SHMATED ? "shmat" : "mmap")
1880     );
1881   }
1882 
1883   // Check that range is a sub range of memory block (or equal to memory block);
1884   // also check that range is fully page aligned to the page size if the block.
1885   void assert_is_valid_subrange(char* p, size_t s) const {
1886     if (!contains_range(p, s)) {
1887       trcVerbose("[" PTR_FORMAT " - " PTR_FORMAT "] is not a sub "
1888               "range of [" PTR_FORMAT " - " PTR_FORMAT "].",
1889               p, p + s, addr, addr + size);
1890       guarantee0(false);
1891     }
1892     if (!is_aligned_to(p, pagesize) || !is_aligned_to(p + s, pagesize)) {
1893       trcVerbose("range [" PTR_FORMAT " - " PTR_FORMAT "] is not"
1894               " aligned to pagesize (%lu)", p, p + s, (unsigned long) pagesize);
1895       guarantee0(false);
1896     }
1897   }
1898 };
1899 
1900 static struct {
1901   vmembk_t* first;
1902   MiscUtils::CritSect cs;
1903 } vmem;
1904 
1905 static void vmembk_add(char* addr, size_t size, size_t pagesize, int type) {
1906   vmembk_t* p = (vmembk_t*) ::malloc(sizeof(vmembk_t));
1907   assert0(p);
1908   if (p) {
1909     MiscUtils::AutoCritSect lck(&vmem.cs);
1910     p->addr = addr; p->size = size;
1911     p->pagesize = pagesize;
1912     p->type = type;
1913     p->next = vmem.first;
1914     vmem.first = p;
1915   }
1916 }
1917 
1918 static vmembk_t* vmembk_find(char* addr) {
1919   MiscUtils::AutoCritSect lck(&vmem.cs);
1920   for (vmembk_t* p = vmem.first; p; p = p->next) {
1921     if (p->addr <= addr && (p->addr + p->size) > addr) {
1922       return p;
1923     }
1924   }
1925   return NULL;
1926 }
1927 
1928 static void vmembk_remove(vmembk_t* p0) {
1929   MiscUtils::AutoCritSect lck(&vmem.cs);
1930   assert0(p0);
1931   assert0(vmem.first); // List should not be empty.
1932   for (vmembk_t** pp = &(vmem.first); *pp; pp = &((*pp)->next)) {
1933     if (*pp == p0) {
1934       *pp = p0->next;
1935       ::free(p0);
1936       return;
1937     }
1938   }
1939   assert0(false); // Not found?
1940 }
1941 
1942 static void vmembk_print_on(outputStream* os) {
1943   MiscUtils::AutoCritSect lck(&vmem.cs);
1944   for (vmembk_t* vmi = vmem.first; vmi; vmi = vmi->next) {
1945     vmi->print_on(os);
1946     os->cr();
1947   }
1948 }
1949 
1950 // Reserve and attach a section of System V memory.
1951 // If <requested_addr> is not NULL, function will attempt to attach the memory at the given
1952 // address. Failing that, it will attach the memory anywhere.
1953 // If <requested_addr> is NULL, function will attach the memory anywhere.
1954 //
1955 // <alignment_hint> is being ignored by this function. It is very probable however that the
1956 // alignment requirements are met anyway, because shmat() attaches at 256M boundaries.
1957 // Should this be not enogh, we can put more work into it.
1958 static char* reserve_shmated_memory (
1959   size_t bytes,
1960   char* requested_addr,
1961   size_t alignment_hint) {
1962 
1963   trcVerbose("reserve_shmated_memory " UINTX_FORMAT " bytes, wishaddress "
1964     PTR_FORMAT ", alignment_hint " UINTX_FORMAT "...",
1965     bytes, requested_addr, alignment_hint);
1966 
1967   // Either give me wish address or wish alignment but not both.
1968   assert0(!(requested_addr != NULL && alignment_hint != 0));
1969 
1970   // We must prevent anyone from attaching too close to the
1971   // BRK because that may cause malloc OOM.
1972   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
1973     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
1974       "Will attach anywhere.", requested_addr);
1975     // Act like the OS refused to attach there.
1976     requested_addr = NULL;
1977   }
1978 
1979   // For old AS/400's (V5R4 and older) we should not even be here - System V shared memory is not
1980   // really supported (max size 4GB), so reserve_mmapped_memory should have been used instead.
1981   if (os::Aix::on_pase_V5R4_or_older()) {
1982     ShouldNotReachHere();
1983   }
1984 
1985   // Align size of shm up to 64K to avoid errors if we later try to change the page size.
1986   const size_t size = align_up(bytes, 64*K);
1987 
1988   // Reserve the shared segment.
1989   int shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | S_IRUSR | S_IWUSR);
1990   if (shmid == -1) {
1991     trcVerbose("shmget(.., " UINTX_FORMAT ", ..) failed (errno: %d).", size, errno);
1992     return NULL;
1993   }
1994 
1995   // Important note:
1996   // It is very important that we, upon leaving this function, do not leave a shm segment alive.
1997   // We must right after attaching it remove it from the system. System V shm segments are global and
1998   // survive the process.
1999   // So, from here on: Do not assert, do not return, until we have called shmctl(IPC_RMID) (A).
2000 
2001   struct shmid_ds shmbuf;
2002   memset(&shmbuf, 0, sizeof(shmbuf));
2003   shmbuf.shm_pagesize = 64*K;
2004   if (shmctl(shmid, SHM_PAGESIZE, &shmbuf) != 0) {
2005     trcVerbose("Failed to set page size (need " UINTX_FORMAT " 64K pages) - shmctl failed with %d.",
2006                size / (64*K), errno);
2007     // I want to know if this ever happens.
2008     assert(false, "failed to set page size for shmat");
2009   }
2010 
2011   // Now attach the shared segment.
2012   // Note that I attach with SHM_RND - which means that the requested address is rounded down, if
2013   // needed, to the next lowest segment boundary. Otherwise the attach would fail if the address
2014   // were not a segment boundary.
2015   char* const addr = (char*) shmat(shmid, requested_addr, SHM_RND);
2016   const int errno_shmat = errno;
2017 
2018   // (A) Right after shmat and before handing shmat errors delete the shm segment.
2019   if (::shmctl(shmid, IPC_RMID, NULL) == -1) {
2020     trcVerbose("shmctl(%u, IPC_RMID) failed (%d)\n", shmid, errno);
2021     assert(false, "failed to remove shared memory segment!");
2022   }
2023 
2024   // Handle shmat error. If we failed to attach, just return.
2025   if (addr == (char*)-1) {
2026     trcVerbose("Failed to attach segment at " PTR_FORMAT " (%d).", requested_addr, errno_shmat);
2027     return NULL;
2028   }
2029 
2030   // Just for info: query the real page size. In case setting the page size did not
2031   // work (see above), the system may have given us something other then 4K (LDR_CNTRL).
2032   const size_t real_pagesize = os::Aix::query_pagesize(addr);
2033   if (real_pagesize != shmbuf.shm_pagesize) {
2034     trcVerbose("pagesize is, surprisingly, %h.", real_pagesize);
2035   }
2036 
2037   if (addr) {
2038     trcVerbose("shm-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes, " UINTX_FORMAT " %s pages)",
2039       addr, addr + size - 1, size, size/real_pagesize, describe_pagesize(real_pagesize));
2040   } else {
2041     if (requested_addr != NULL) {
2042       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at with address " PTR_FORMAT ".", size, requested_addr);
2043     } else {
2044       trcVerbose("failed to shm-allocate " UINTX_FORMAT " bytes at any address.", size);
2045     }
2046   }
2047 
2048   // book-keeping
2049   vmembk_add(addr, size, real_pagesize, VMEM_SHMATED);
2050   assert0(is_aligned_to(addr, os::vm_page_size()));
2051 
2052   return addr;
2053 }
2054 
2055 static bool release_shmated_memory(char* addr, size_t size) {
2056 
2057   trcVerbose("release_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2058     addr, addr + size - 1);
2059 
2060   bool rc = false;
2061 
2062   // TODO: is there a way to verify shm size without doing bookkeeping?
2063   if (::shmdt(addr) != 0) {
2064     trcVerbose("error (%d).", errno);
2065   } else {
2066     trcVerbose("ok.");
2067     rc = true;
2068   }
2069   return rc;
2070 }
2071 
2072 static bool uncommit_shmated_memory(char* addr, size_t size) {
2073   trcVerbose("uncommit_shmated_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2074     addr, addr + size - 1);
2075 
2076   const bool rc = my_disclaim64(addr, size);
2077 
2078   if (!rc) {
2079     trcVerbose("my_disclaim64(" PTR_FORMAT ", " UINTX_FORMAT ") failed.\n", addr, size);
2080     return false;
2081   }
2082   return true;
2083 }
2084 
2085 ////////////////////////////////  mmap-based routines /////////////////////////////////
2086 
2087 // Reserve memory via mmap.
2088 // If <requested_addr> is given, an attempt is made to attach at the given address.
2089 // Failing that, memory is allocated at any address.
2090 // If <alignment_hint> is given and <requested_addr> is NULL, an attempt is made to
2091 // allocate at an address aligned with the given alignment. Failing that, memory
2092 // is aligned anywhere.
2093 static char* reserve_mmaped_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2094   trcVerbose("reserve_mmaped_memory " UINTX_FORMAT " bytes, wishaddress " PTR_FORMAT ", "
2095     "alignment_hint " UINTX_FORMAT "...",
2096     bytes, requested_addr, alignment_hint);
2097 
2098   // If a wish address is given, but not aligned to 4K page boundary, mmap will fail.
2099   if (requested_addr && !is_aligned_to(requested_addr, os::vm_page_size()) != 0) {
2100     trcVerbose("Wish address " PTR_FORMAT " not aligned to page boundary.", requested_addr);
2101     return NULL;
2102   }
2103 
2104   // We must prevent anyone from attaching too close to the
2105   // BRK because that may cause malloc OOM.
2106   if (requested_addr != NULL && is_close_to_brk((address)requested_addr)) {
2107     trcVerbose("Wish address " PTR_FORMAT " is too close to the BRK segment. "
2108       "Will attach anywhere.", requested_addr);
2109     // Act like the OS refused to attach there.
2110     requested_addr = NULL;
2111   }
2112 
2113   // Specify one or the other but not both.
2114   assert0(!(requested_addr != NULL && alignment_hint > 0));
2115 
2116   // In 64K mode, we claim the global page size (os::vm_page_size())
2117   // is 64K. This is one of the few points where that illusion may
2118   // break, because mmap() will always return memory aligned to 4K. So
2119   // we must ensure we only ever return memory aligned to 64k.
2120   if (alignment_hint) {
2121     alignment_hint = lcm(alignment_hint, os::vm_page_size());
2122   } else {
2123     alignment_hint = os::vm_page_size();
2124   }
2125 
2126   // Size shall always be a multiple of os::vm_page_size (esp. in 64K mode).
2127   const size_t size = align_up(bytes, os::vm_page_size());
2128 
2129   // alignment: Allocate memory large enough to include an aligned range of the right size and
2130   // cut off the leading and trailing waste pages.
2131   assert0(alignment_hint != 0 && is_aligned_to(alignment_hint, os::vm_page_size())); // see above
2132   const size_t extra_size = size + alignment_hint;
2133 
2134   // Note: MAP_SHARED (instead of MAP_PRIVATE) needed to be able to
2135   // later use msync(MS_INVALIDATE) (see os::uncommit_memory).
2136   int flags = MAP_ANONYMOUS | MAP_SHARED;
2137 
2138   // MAP_FIXED is needed to enforce requested_addr - manpage is vague about what
2139   // it means if wishaddress is given but MAP_FIXED is not set.
2140   //
2141   // Important! Behaviour differs depending on whether SPEC1170 mode is active or not.
2142   // SPEC1170 mode active: behaviour like POSIX, MAP_FIXED will clobber existing mappings.
2143   // SPEC1170 mode not active: behaviour, unlike POSIX, is that no existing mappings will
2144   // get clobbered.
2145   if (requested_addr != NULL) {
2146     if (!os::Aix::xpg_sus_mode()) {  // not SPEC1170 Behaviour
2147       flags |= MAP_FIXED;
2148     }
2149   }
2150 
2151   char* addr = (char*)::mmap(requested_addr, extra_size,
2152       PROT_READ|PROT_WRITE|PROT_EXEC, flags, -1, 0);
2153 
2154   if (addr == MAP_FAILED) {
2155     trcVerbose("mmap(" PTR_FORMAT ", " UINTX_FORMAT ", ..) failed (%d)", requested_addr, size, errno);
2156     return NULL;
2157   }
2158 
2159   // Handle alignment.
2160   char* const addr_aligned = align_up(addr, alignment_hint);
2161   const size_t waste_pre = addr_aligned - addr;
2162   char* const addr_aligned_end = addr_aligned + size;
2163   const size_t waste_post = extra_size - waste_pre - size;
2164   if (waste_pre > 0) {
2165     ::munmap(addr, waste_pre);
2166   }
2167   if (waste_post > 0) {
2168     ::munmap(addr_aligned_end, waste_post);
2169   }
2170   addr = addr_aligned;
2171 
2172   if (addr) {
2173     trcVerbose("mmap-allocated " PTR_FORMAT " .. " PTR_FORMAT " (" UINTX_FORMAT " bytes)",
2174       addr, addr + bytes, bytes);
2175   } else {
2176     if (requested_addr != NULL) {
2177       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at wish address " PTR_FORMAT ".", bytes, requested_addr);
2178     } else {
2179       trcVerbose("failed to mmap-allocate " UINTX_FORMAT " bytes at any address.", bytes);
2180     }
2181   }
2182 
2183   // bookkeeping
2184   vmembk_add(addr, size, 4*K, VMEM_MAPPED);
2185 
2186   // Test alignment, see above.
2187   assert0(is_aligned_to(addr, os::vm_page_size()));
2188 
2189   return addr;
2190 }
2191 
2192 static bool release_mmaped_memory(char* addr, size_t size) {
2193   assert0(is_aligned_to(addr, os::vm_page_size()));
2194   assert0(is_aligned_to(size, os::vm_page_size()));
2195 
2196   trcVerbose("release_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2197     addr, addr + size - 1);
2198   bool rc = false;
2199 
2200   if (::munmap(addr, size) != 0) {
2201     trcVerbose("failed (%d)\n", errno);
2202     rc = false;
2203   } else {
2204     trcVerbose("ok.");
2205     rc = true;
2206   }
2207 
2208   return rc;
2209 }
2210 
2211 static bool uncommit_mmaped_memory(char* addr, size_t size) {
2212 
2213   assert0(is_aligned_to(addr, os::vm_page_size()));
2214   assert0(is_aligned_to(size, os::vm_page_size()));
2215 
2216   trcVerbose("uncommit_mmaped_memory [" PTR_FORMAT " - " PTR_FORMAT "].",
2217     addr, addr + size - 1);
2218   bool rc = false;
2219 
2220   // Uncommit mmap memory with msync MS_INVALIDATE.
2221   if (::msync(addr, size, MS_INVALIDATE) != 0) {
2222     trcVerbose("failed (%d)\n", errno);
2223     rc = false;
2224   } else {
2225     trcVerbose("ok.");
2226     rc = true;
2227   }
2228 
2229   return rc;
2230 }
2231 
2232 int os::vm_page_size() {
2233   // Seems redundant as all get out.
2234   assert(os::Aix::page_size() != -1, "must call os::init");
2235   return os::Aix::page_size();
2236 }
2237 
2238 // Aix allocates memory by pages.
2239 int os::vm_allocation_granularity() {
2240   assert(os::Aix::page_size() != -1, "must call os::init");
2241   return os::Aix::page_size();
2242 }
2243 
2244 #ifdef PRODUCT
2245 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2246                                     int err) {
2247   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2248           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2249           os::errno_name(err), err);
2250 }
2251 #endif
2252 
2253 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2254                                   const char* mesg) {
2255   assert(mesg != NULL, "mesg must be specified");
2256   if (!pd_commit_memory(addr, size, exec)) {
2257     // Add extra info in product mode for vm_exit_out_of_memory():
2258     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2259     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2260   }
2261 }
2262 
2263 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2264 
2265   assert(is_aligned_to(addr, os::vm_page_size()),
2266     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2267     p2i(addr), os::vm_page_size());
2268   assert(is_aligned_to(size, os::vm_page_size()),
2269     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2270     size, os::vm_page_size());
2271 
2272   vmembk_t* const vmi = vmembk_find(addr);
2273   guarantee0(vmi);
2274   vmi->assert_is_valid_subrange(addr, size);
2275 
2276   trcVerbose("commit_memory [" PTR_FORMAT " - " PTR_FORMAT "].", addr, addr + size - 1);
2277 
2278   if (UseExplicitCommit) {
2279     // AIX commits memory on touch. So, touch all pages to be committed.
2280     for (char* p = addr; p < (addr + size); p += 4*K) {
2281       *p = '\0';
2282     }
2283   }
2284 
2285   return true;
2286 }
2287 
2288 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, bool exec) {
2289   return pd_commit_memory(addr, size, exec);
2290 }
2291 
2292 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2293                                   size_t alignment_hint, bool exec,
2294                                   const char* mesg) {
2295   // Alignment_hint is ignored on this OS.
2296   pd_commit_memory_or_exit(addr, size, exec, mesg);
2297 }
2298 
2299 bool os::pd_uncommit_memory(char* addr, size_t size) {
2300   assert(is_aligned_to(addr, os::vm_page_size()),
2301     "addr " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2302     p2i(addr), os::vm_page_size());
2303   assert(is_aligned_to(size, os::vm_page_size()),
2304     "size " PTR_FORMAT " not aligned to vm_page_size (" PTR_FORMAT ")",
2305     size, os::vm_page_size());
2306 
2307   // Dynamically do different things for mmap/shmat.
2308   const vmembk_t* const vmi = vmembk_find(addr);
2309   guarantee0(vmi);
2310   vmi->assert_is_valid_subrange(addr, size);
2311 
2312   if (vmi->type == VMEM_SHMATED) {
2313     return uncommit_shmated_memory(addr, size);
2314   } else {
2315     return uncommit_mmaped_memory(addr, size);
2316   }
2317 }
2318 
2319 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2320   // Do not call this; no need to commit stack pages on AIX.
2321   ShouldNotReachHere();
2322   return true;
2323 }
2324 
2325 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2326   // Do not call this; no need to commit stack pages on AIX.
2327   ShouldNotReachHere();
2328   return true;
2329 }
2330 
2331 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2332 }
2333 
2334 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2335 }
2336 
2337 void os::numa_make_global(char *addr, size_t bytes) {
2338 }
2339 
2340 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2341 }
2342 
2343 bool os::numa_topology_changed() {
2344   return false;
2345 }
2346 
2347 size_t os::numa_get_groups_num() {
2348   return 1;
2349 }
2350 
2351 int os::numa_get_group_id() {
2352   return 0;
2353 }
2354 
2355 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2356   if (size > 0) {
2357     ids[0] = 0;
2358     return 1;
2359   }
2360   return 0;
2361 }
2362 
2363 bool os::get_page_info(char *start, page_info* info) {
2364   return false;
2365 }
2366 
2367 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2368   return end;
2369 }
2370 
2371 // Reserves and attaches a shared memory segment.
2372 // Will assert if a wish address is given and could not be obtained.
2373 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, size_t alignment_hint) {
2374 
2375   // All other Unices do a mmap(MAP_FIXED) if the addr is given,
2376   // thereby clobbering old mappings at that place. That is probably
2377   // not intended, never used and almost certainly an error were it
2378   // ever be used this way (to try attaching at a specified address
2379   // without clobbering old mappings an alternate API exists,
2380   // os::attempt_reserve_memory_at()).
2381   // Instead of mimicking the dangerous coding of the other platforms, here I
2382   // just ignore the request address (release) or assert(debug).
2383   assert0(requested_addr == NULL);
2384 
2385   // Always round to os::vm_page_size(), which may be larger than 4K.
2386   bytes = align_up(bytes, os::vm_page_size());
2387   const size_t alignment_hint0 =
2388     alignment_hint ? align_up(alignment_hint, os::vm_page_size()) : 0;
2389 
2390   // In 4K mode always use mmap.
2391   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2392   if (os::vm_page_size() == 4*K) {
2393     return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2394   } else {
2395     if (bytes >= Use64KPagesThreshold) {
2396       return reserve_shmated_memory(bytes, requested_addr, alignment_hint);
2397     } else {
2398       return reserve_mmaped_memory(bytes, requested_addr, alignment_hint);
2399     }
2400   }
2401 }
2402 
2403 bool os::pd_release_memory(char* addr, size_t size) {
2404 
2405   // Dynamically do different things for mmap/shmat.
2406   vmembk_t* const vmi = vmembk_find(addr);
2407   guarantee0(vmi);
2408 
2409   // Always round to os::vm_page_size(), which may be larger than 4K.
2410   size = align_up(size, os::vm_page_size());
2411   addr = align_up(addr, os::vm_page_size());
2412 
2413   bool rc = false;
2414   bool remove_bookkeeping = false;
2415   if (vmi->type == VMEM_SHMATED) {
2416     // For shmatted memory, we do:
2417     // - If user wants to release the whole range, release the memory (shmdt).
2418     // - If user only wants to release a partial range, uncommit (disclaim) that
2419     //   range. That way, at least, we do not use memory anymore (bust still page
2420     //   table space).
2421     vmi->assert_is_valid_subrange(addr, size);
2422     if (addr == vmi->addr && size == vmi->size) {
2423       rc = release_shmated_memory(addr, size);
2424       remove_bookkeeping = true;
2425     } else {
2426       rc = uncommit_shmated_memory(addr, size);
2427     }
2428   } else {
2429     // User may unmap partial regions but region has to be fully contained.
2430 #ifdef ASSERT
2431     vmi->assert_is_valid_subrange(addr, size);
2432 #endif
2433     rc = release_mmaped_memory(addr, size);
2434     remove_bookkeeping = true;
2435   }
2436 
2437   // update bookkeeping
2438   if (rc && remove_bookkeeping) {
2439     vmembk_remove(vmi);
2440   }
2441 
2442   return rc;
2443 }
2444 
2445 static bool checked_mprotect(char* addr, size_t size, int prot) {
2446 
2447   // Little problem here: if SPEC1170 behaviour is off, mprotect() on AIX will
2448   // not tell me if protection failed when trying to protect an un-protectable range.
2449   //
2450   // This means if the memory was allocated using shmget/shmat, protection wont work
2451   // but mprotect will still return 0:
2452   //
2453   // See http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/mprotect.htm
2454 
2455   bool rc = ::mprotect(addr, size, prot) == 0 ? true : false;
2456 
2457   if (!rc) {
2458     const char* const s_errno = os::errno_name(errno);
2459     warning("mprotect(" PTR_FORMAT "-" PTR_FORMAT ", 0x%X) failed (%s).", addr, addr + size, prot, s_errno);
2460     return false;
2461   }
2462 
2463   // mprotect success check
2464   //
2465   // Mprotect said it changed the protection but can I believe it?
2466   //
2467   // To be sure I need to check the protection afterwards. Try to
2468   // read from protected memory and check whether that causes a segfault.
2469   //
2470   if (!os::Aix::xpg_sus_mode()) {
2471 
2472     if (CanUseSafeFetch32()) {
2473 
2474       const bool read_protected =
2475         (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2476          SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2477 
2478       if (prot & PROT_READ) {
2479         rc = !read_protected;
2480       } else {
2481         rc = read_protected;
2482       }
2483 
2484       if (!rc) {
2485         if (os::Aix::on_pase()) {
2486           // There is an issue on older PASE systems where mprotect() will return success but the
2487           // memory will not be protected.
2488           // This has nothing to do with the problem of using mproect() on SPEC1170 incompatible
2489           // machines; we only see it rarely, when using mprotect() to protect the guard page of
2490           // a stack. It is an OS error.
2491           //
2492           // A valid strategy is just to try again. This usually works. :-/
2493 
2494           ::usleep(1000);
2495           if (::mprotect(addr, size, prot) == 0) {
2496             const bool read_protected_2 =
2497               (SafeFetch32((int*)addr, 0x12345678) == 0x12345678 &&
2498               SafeFetch32((int*)addr, 0x76543210) == 0x76543210) ? true : false;
2499             rc = true;
2500           }
2501         }
2502       }
2503     }
2504   }
2505 
2506   assert(rc == true, "mprotect failed.");
2507 
2508   return rc;
2509 }
2510 
2511 // Set protections specified
2512 bool os::protect_memory(char* addr, size_t size, ProtType prot, bool is_committed) {
2513   unsigned int p = 0;
2514   switch (prot) {
2515   case MEM_PROT_NONE: p = PROT_NONE; break;
2516   case MEM_PROT_READ: p = PROT_READ; break;
2517   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2518   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2519   default:
2520     ShouldNotReachHere();
2521   }
2522   // is_committed is unused.
2523   return checked_mprotect(addr, size, p);
2524 }
2525 
2526 bool os::guard_memory(char* addr, size_t size) {
2527   return checked_mprotect(addr, size, PROT_NONE);
2528 }
2529 
2530 bool os::unguard_memory(char* addr, size_t size) {
2531   return checked_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
2532 }
2533 
2534 // Large page support
2535 
2536 static size_t _large_page_size = 0;
2537 
2538 // Enable large page support if OS allows that.
2539 void os::large_page_init() {
2540   return; // Nothing to do. See query_multipage_support and friends.
2541 }
2542 
2543 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2544   // reserve_memory_special() is used to allocate large paged memory. On AIX, we implement
2545   // 64k paged memory reservation using the normal memory allocation paths (os::reserve_memory()),
2546   // so this is not needed.
2547   assert(false, "should not be called on AIX");
2548   return NULL;
2549 }
2550 
2551 bool os::release_memory_special(char* base, size_t bytes) {
2552   // Detaching the SHM segment will also delete it, see reserve_memory_special().
2553   Unimplemented();
2554   return false;
2555 }
2556 
2557 size_t os::large_page_size() {
2558   return _large_page_size;
2559 }
2560 
2561 bool os::can_commit_large_page_memory() {
2562   // Does not matter, we do not support huge pages.
2563   return false;
2564 }
2565 
2566 bool os::can_execute_large_page_memory() {
2567   // Does not matter, we do not support huge pages.
2568   return false;
2569 }
2570 
2571 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
2572   assert(file_desc >= 0, "file_desc is not valid");
2573   char* result = NULL;
2574 
2575   // Always round to os::vm_page_size(), which may be larger than 4K.
2576   bytes = align_up(bytes, os::vm_page_size());
2577   result = reserve_mmaped_memory(bytes, requested_addr, 0);
2578 
2579   if (result != NULL) {
2580     if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
2581       vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
2582     }
2583   }
2584   return result;
2585 }
2586 
2587 // Reserve memory at an arbitrary address, only if that area is
2588 // available (and not reserved for something else).
2589 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2590   char* addr = NULL;
2591 
2592   // Always round to os::vm_page_size(), which may be larger than 4K.
2593   bytes = align_up(bytes, os::vm_page_size());
2594 
2595   // In 4K mode always use mmap.
2596   // In 64K mode allocate small sizes with mmap, large ones with 64K shmatted.
2597   if (os::vm_page_size() == 4*K) {
2598     return reserve_mmaped_memory(bytes, requested_addr, 0);
2599   } else {
2600     if (bytes >= Use64KPagesThreshold) {
2601       return reserve_shmated_memory(bytes, requested_addr, 0);
2602     } else {
2603       return reserve_mmaped_memory(bytes, requested_addr, 0);
2604     }
2605   }
2606 
2607   return addr;
2608 }
2609 
2610 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2611   return ::read(fd, buf, nBytes);
2612 }
2613 
2614 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
2615   return ::pread(fd, buf, nBytes, offset);
2616 }
2617 
2618 void os::naked_short_sleep(jlong ms) {
2619   struct timespec req;
2620 
2621   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2622   req.tv_sec = 0;
2623   if (ms > 0) {
2624     req.tv_nsec = (ms % 1000) * 1000000;
2625   }
2626   else {
2627     req.tv_nsec = 1;
2628   }
2629 
2630   nanosleep(&req, NULL);
2631 
2632   return;
2633 }
2634 
2635 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2636 void os::infinite_sleep() {
2637   while (true) {    // sleep forever ...
2638     ::sleep(100);   // ... 100 seconds at a time
2639   }
2640 }
2641 
2642 // Used to convert frequent JVM_Yield() to nops
2643 bool os::dont_yield() {
2644   return DontYieldALot;
2645 }
2646 
2647 void os::naked_yield() {
2648   sched_yield();
2649 }
2650 
2651 ////////////////////////////////////////////////////////////////////////////////
2652 // thread priority support
2653 
2654 // From AIX manpage to pthread_setschedparam
2655 // (see: http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?
2656 //    topic=/com.ibm.aix.basetechref/doc/basetrf1/pthread_setschedparam.htm):
2657 //
2658 // "If schedpolicy is SCHED_OTHER, then sched_priority must be in the
2659 // range from 40 to 80, where 40 is the least favored priority and 80
2660 // is the most favored."
2661 //
2662 // (Actually, I doubt this even has an impact on AIX, as we do kernel
2663 // scheduling there; however, this still leaves iSeries.)
2664 //
2665 // We use the same values for AIX and PASE.
2666 int os::java_to_os_priority[CriticalPriority + 1] = {
2667   54,             // 0 Entry should never be used
2668 
2669   55,             // 1 MinPriority
2670   55,             // 2
2671   56,             // 3
2672 
2673   56,             // 4
2674   57,             // 5 NormPriority
2675   57,             // 6
2676 
2677   58,             // 7
2678   58,             // 8
2679   59,             // 9 NearMaxPriority
2680 
2681   60,             // 10 MaxPriority
2682 
2683   60              // 11 CriticalPriority
2684 };
2685 
2686 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2687   if (!UseThreadPriorities) return OS_OK;
2688   pthread_t thr = thread->osthread()->pthread_id();
2689   int policy = SCHED_OTHER;
2690   struct sched_param param;
2691   param.sched_priority = newpri;
2692   int ret = pthread_setschedparam(thr, policy, &param);
2693 
2694   if (ret != 0) {
2695     trcVerbose("Could not change priority for thread %d to %d (error %d, %s)",
2696         (int)thr, newpri, ret, os::errno_name(ret));
2697   }
2698   return (ret == 0) ? OS_OK : OS_ERR;
2699 }
2700 
2701 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2702   if (!UseThreadPriorities) {
2703     *priority_ptr = java_to_os_priority[NormPriority];
2704     return OS_OK;
2705   }
2706   pthread_t thr = thread->osthread()->pthread_id();
2707   int policy = SCHED_OTHER;
2708   struct sched_param param;
2709   int ret = pthread_getschedparam(thr, &policy, &param);
2710   *priority_ptr = param.sched_priority;
2711 
2712   return (ret == 0) ? OS_OK : OS_ERR;
2713 }
2714 
2715 // Hint to the underlying OS that a task switch would not be good.
2716 // Void return because it's a hint and can fail.
2717 void os::hint_no_preempt() {}
2718 
2719 ////////////////////////////////////////////////////////////////////////////////
2720 // suspend/resume support
2721 
2722 //  The low-level signal-based suspend/resume support is a remnant from the
2723 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2724 //  within hotspot. Currently used by JFR's OSThreadSampler
2725 //
2726 //  The remaining code is greatly simplified from the more general suspension
2727 //  code that used to be used.
2728 //
2729 //  The protocol is quite simple:
2730 //  - suspend:
2731 //      - sends a signal to the target thread
2732 //      - polls the suspend state of the osthread using a yield loop
2733 //      - target thread signal handler (SR_handler) sets suspend state
2734 //        and blocks in sigsuspend until continued
2735 //  - resume:
2736 //      - sets target osthread state to continue
2737 //      - sends signal to end the sigsuspend loop in the SR_handler
2738 //
2739 //  Note that the SR_lock plays no role in this suspend/resume protocol,
2740 //  but is checked for NULL in SR_handler as a thread termination indicator.
2741 //  The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
2742 //
2743 //  Note that resume_clear_context() and suspend_save_context() are needed
2744 //  by SR_handler(), so that fetch_frame_from_ucontext() works,
2745 //  which in part is used by:
2746 //    - Forte Analyzer: AsyncGetCallTrace()
2747 //    - StackBanging: get_frame_at_stack_banging_point()
2748 
2749 static void resume_clear_context(OSThread *osthread) {
2750   osthread->set_ucontext(NULL);
2751   osthread->set_siginfo(NULL);
2752 }
2753 
2754 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2755   osthread->set_ucontext(context);
2756   osthread->set_siginfo(siginfo);
2757 }
2758 
2759 //
2760 // Handler function invoked when a thread's execution is suspended or
2761 // resumed. We have to be careful that only async-safe functions are
2762 // called here (Note: most pthread functions are not async safe and
2763 // should be avoided.)
2764 //
2765 // Note: sigwait() is a more natural fit than sigsuspend() from an
2766 // interface point of view, but sigwait() prevents the signal hander
2767 // from being run. libpthread would get very confused by not having
2768 // its signal handlers run and prevents sigwait()'s use with the
2769 // mutex granting granting signal.
2770 //
2771 // Currently only ever called on the VMThread and JavaThreads (PC sampling).
2772 //
2773 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2774   // Save and restore errno to avoid confusing native code with EINTR
2775   // after sigsuspend.
2776   int old_errno = errno;
2777 
2778   Thread* thread = Thread::current_or_null_safe();
2779   assert(thread != NULL, "Missing current thread in SR_handler");
2780 
2781   // On some systems we have seen signal delivery get "stuck" until the signal
2782   // mask is changed as part of thread termination. Check that the current thread
2783   // has not already terminated (via SR_lock()) - else the following assertion
2784   // will fail because the thread is no longer a JavaThread as the ~JavaThread
2785   // destructor has completed.
2786 
2787   if (thread->SR_lock() == NULL) {
2788     return;
2789   }
2790 
2791   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2792 
2793   OSThread* osthread = thread->osthread();
2794 
2795   os::SuspendResume::State current = osthread->sr.state();
2796   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2797     suspend_save_context(osthread, siginfo, context);
2798 
2799     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2800     os::SuspendResume::State state = osthread->sr.suspended();
2801     if (state == os::SuspendResume::SR_SUSPENDED) {
2802       sigset_t suspend_set;  // signals for sigsuspend()
2803 
2804       // get current set of blocked signals and unblock resume signal
2805       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2806       sigdelset(&suspend_set, SR_signum);
2807 
2808       // wait here until we are resumed
2809       while (1) {
2810         sigsuspend(&suspend_set);
2811 
2812         os::SuspendResume::State result = osthread->sr.running();
2813         if (result == os::SuspendResume::SR_RUNNING) {
2814           break;
2815         }
2816       }
2817 
2818     } else if (state == os::SuspendResume::SR_RUNNING) {
2819       // request was cancelled, continue
2820     } else {
2821       ShouldNotReachHere();
2822     }
2823 
2824     resume_clear_context(osthread);
2825   } else if (current == os::SuspendResume::SR_RUNNING) {
2826     // request was cancelled, continue
2827   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2828     // ignore
2829   } else {
2830     ShouldNotReachHere();
2831   }
2832 
2833   errno = old_errno;
2834 }
2835 
2836 static int SR_initialize() {
2837   struct sigaction act;
2838   char *s;
2839   // Get signal number to use for suspend/resume
2840   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2841     int sig = ::strtol(s, 0, 10);
2842     if (sig > MAX2(SIGSEGV, SIGBUS) &&  // See 4355769.
2843         sig < NSIG) {                   // Must be legal signal and fit into sigflags[].
2844       SR_signum = sig;
2845     } else {
2846       warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
2847               sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
2848     }
2849   }
2850 
2851   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2852         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2853 
2854   sigemptyset(&SR_sigset);
2855   sigaddset(&SR_sigset, SR_signum);
2856 
2857   // Set up signal handler for suspend/resume.
2858   act.sa_flags = SA_RESTART|SA_SIGINFO;
2859   act.sa_handler = (void (*)(int)) SR_handler;
2860 
2861   // SR_signum is blocked by default.
2862   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2863 
2864   if (sigaction(SR_signum, &act, 0) == -1) {
2865     return -1;
2866   }
2867 
2868   // Save signal flag
2869   os::Aix::set_our_sigflags(SR_signum, act.sa_flags);
2870   return 0;
2871 }
2872 
2873 static int SR_finalize() {
2874   return 0;
2875 }
2876 
2877 static int sr_notify(OSThread* osthread) {
2878   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2879   assert_status(status == 0, status, "pthread_kill");
2880   return status;
2881 }
2882 
2883 // "Randomly" selected value for how long we want to spin
2884 // before bailing out on suspending a thread, also how often
2885 // we send a signal to a thread we want to resume
2886 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2887 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2888 
2889 // returns true on success and false on error - really an error is fatal
2890 // but this seems the normal response to library errors
2891 static bool do_suspend(OSThread* osthread) {
2892   assert(osthread->sr.is_running(), "thread should be running");
2893   // mark as suspended and send signal
2894 
2895   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2896     // failed to switch, state wasn't running?
2897     ShouldNotReachHere();
2898     return false;
2899   }
2900 
2901   if (sr_notify(osthread) != 0) {
2902     // try to cancel, switch to running
2903 
2904     os::SuspendResume::State result = osthread->sr.cancel_suspend();
2905     if (result == os::SuspendResume::SR_RUNNING) {
2906       // cancelled
2907       return false;
2908     } else if (result == os::SuspendResume::SR_SUSPENDED) {
2909       // somehow managed to suspend
2910       return true;
2911     } else {
2912       ShouldNotReachHere();
2913       return false;
2914     }
2915   }
2916 
2917   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2918 
2919   for (int n = 0; !osthread->sr.is_suspended(); n++) {
2920     for (int i = 0; i < RANDOMLY_LARGE_INTEGER2 && !osthread->sr.is_suspended(); i++) {
2921       os::naked_yield();
2922     }
2923 
2924     // timeout, try to cancel the request
2925     if (n >= RANDOMLY_LARGE_INTEGER) {
2926       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2927       if (cancelled == os::SuspendResume::SR_RUNNING) {
2928         return false;
2929       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
2930         return true;
2931       } else {
2932         ShouldNotReachHere();
2933         return false;
2934       }
2935     }
2936   }
2937 
2938   guarantee(osthread->sr.is_suspended(), "Must be suspended");
2939   return true;
2940 }
2941 
2942 static void do_resume(OSThread* osthread) {
2943   //assert(osthread->sr.is_suspended(), "thread should be suspended");
2944 
2945   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
2946     // failed to switch to WAKEUP_REQUEST
2947     ShouldNotReachHere();
2948     return;
2949   }
2950 
2951   while (!osthread->sr.is_running()) {
2952     if (sr_notify(osthread) == 0) {
2953       for (int n = 0; n < RANDOMLY_LARGE_INTEGER && !osthread->sr.is_running(); n++) {
2954         for (int i = 0; i < 100 && !osthread->sr.is_running(); i++) {
2955           os::naked_yield();
2956         }
2957       }
2958     } else {
2959       ShouldNotReachHere();
2960     }
2961   }
2962 
2963   guarantee(osthread->sr.is_running(), "Must be running!");
2964 }
2965 
2966 ///////////////////////////////////////////////////////////////////////////////////
2967 // signal handling (except suspend/resume)
2968 
2969 // This routine may be used by user applications as a "hook" to catch signals.
2970 // The user-defined signal handler must pass unrecognized signals to this
2971 // routine, and if it returns true (non-zero), then the signal handler must
2972 // return immediately. If the flag "abort_if_unrecognized" is true, then this
2973 // routine will never retun false (zero), but instead will execute a VM panic
2974 // routine kill the process.
2975 //
2976 // If this routine returns false, it is OK to call it again. This allows
2977 // the user-defined signal handler to perform checks either before or after
2978 // the VM performs its own checks. Naturally, the user code would be making
2979 // a serious error if it tried to handle an exception (such as a null check
2980 // or breakpoint) that the VM was generating for its own correct operation.
2981 //
2982 // This routine may recognize any of the following kinds of signals:
2983 //   SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
2984 // It should be consulted by handlers for any of those signals.
2985 //
2986 // The caller of this routine must pass in the three arguments supplied
2987 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
2988 // field of the structure passed to sigaction(). This routine assumes that
2989 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
2990 //
2991 // Note that the VM will print warnings if it detects conflicting signal
2992 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
2993 //
2994 extern "C" JNIEXPORT int
2995 JVM_handle_aix_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized);
2996 
2997 // Set thread signal mask (for some reason on AIX sigthreadmask() seems
2998 // to be the thing to call; documentation is not terribly clear about whether
2999 // pthread_sigmask also works, and if it does, whether it does the same.
3000 bool set_thread_signal_mask(int how, const sigset_t* set, sigset_t* oset) {
3001   const int rc = ::pthread_sigmask(how, set, oset);
3002   // return value semantics differ slightly for error case:
3003   // pthread_sigmask returns error number, sigthreadmask -1 and sets global errno
3004   // (so, pthread_sigmask is more theadsafe for error handling)
3005   // But success is always 0.
3006   return rc == 0 ? true : false;
3007 }
3008 
3009 // Function to unblock all signals which are, according
3010 // to POSIX, typical program error signals. If they happen while being blocked,
3011 // they typically will bring down the process immediately.
3012 bool unblock_program_error_signals() {
3013   sigset_t set;
3014   ::sigemptyset(&set);
3015   ::sigaddset(&set, SIGILL);
3016   ::sigaddset(&set, SIGBUS);
3017   ::sigaddset(&set, SIGFPE);
3018   ::sigaddset(&set, SIGSEGV);
3019   return set_thread_signal_mask(SIG_UNBLOCK, &set, NULL);
3020 }
3021 
3022 // Renamed from 'signalHandler' to avoid collision with other shared libs.
3023 void javaSignalHandler(int sig, siginfo_t* info, void* uc) {
3024   assert(info != NULL && uc != NULL, "it must be old kernel");
3025 
3026   // Never leave program error signals blocked;
3027   // on all our platforms they would bring down the process immediately when
3028   // getting raised while being blocked.
3029   unblock_program_error_signals();
3030 
3031   int orig_errno = errno;  // Preserve errno value over signal handler.
3032   JVM_handle_aix_signal(sig, info, uc, true);
3033   errno = orig_errno;
3034 }
3035 
3036 // This boolean allows users to forward their own non-matching signals
3037 // to JVM_handle_aix_signal, harmlessly.
3038 bool os::Aix::signal_handlers_are_installed = false;
3039 
3040 // For signal-chaining
3041 struct sigaction sigact[NSIG];
3042 sigset_t sigs;
3043 bool os::Aix::libjsig_is_loaded = false;
3044 typedef struct sigaction *(*get_signal_t)(int);
3045 get_signal_t os::Aix::get_signal_action = NULL;
3046 
3047 struct sigaction* os::Aix::get_chained_signal_action(int sig) {
3048   struct sigaction *actp = NULL;
3049 
3050   if (libjsig_is_loaded) {
3051     // Retrieve the old signal handler from libjsig
3052     actp = (*get_signal_action)(sig);
3053   }
3054   if (actp == NULL) {
3055     // Retrieve the preinstalled signal handler from jvm
3056     actp = get_preinstalled_handler(sig);
3057   }
3058 
3059   return actp;
3060 }
3061 
3062 static bool call_chained_handler(struct sigaction *actp, int sig,
3063                                  siginfo_t *siginfo, void *context) {
3064   // Call the old signal handler
3065   if (actp->sa_handler == SIG_DFL) {
3066     // It's more reasonable to let jvm treat it as an unexpected exception
3067     // instead of taking the default action.
3068     return false;
3069   } else if (actp->sa_handler != SIG_IGN) {
3070     if ((actp->sa_flags & SA_NODEFER) == 0) {
3071       // automaticlly block the signal
3072       sigaddset(&(actp->sa_mask), sig);
3073     }
3074 
3075     sa_handler_t hand = NULL;
3076     sa_sigaction_t sa = NULL;
3077     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3078     // retrieve the chained handler
3079     if (siginfo_flag_set) {
3080       sa = actp->sa_sigaction;
3081     } else {
3082       hand = actp->sa_handler;
3083     }
3084 
3085     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3086       actp->sa_handler = SIG_DFL;
3087     }
3088 
3089     // try to honor the signal mask
3090     sigset_t oset;
3091     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3092 
3093     // call into the chained handler
3094     if (siginfo_flag_set) {
3095       (*sa)(sig, siginfo, context);
3096     } else {
3097       (*hand)(sig);
3098     }
3099 
3100     // restore the signal mask
3101     pthread_sigmask(SIG_SETMASK, &oset, 0);
3102   }
3103   // Tell jvm's signal handler the signal is taken care of.
3104   return true;
3105 }
3106 
3107 bool os::Aix::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3108   bool chained = false;
3109   // signal-chaining
3110   if (UseSignalChaining) {
3111     struct sigaction *actp = get_chained_signal_action(sig);
3112     if (actp != NULL) {
3113       chained = call_chained_handler(actp, sig, siginfo, context);
3114     }
3115   }
3116   return chained;
3117 }
3118 
3119 struct sigaction* os::Aix::get_preinstalled_handler(int sig) {
3120   if (sigismember(&sigs, sig)) {
3121     return &sigact[sig];
3122   }
3123   return NULL;
3124 }
3125 
3126 void os::Aix::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3127   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3128   sigact[sig] = oldAct;
3129   sigaddset(&sigs, sig);
3130 }
3131 
3132 // for diagnostic
3133 int sigflags[NSIG];
3134 
3135 int os::Aix::get_our_sigflags(int sig) {
3136   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3137   return sigflags[sig];
3138 }
3139 
3140 void os::Aix::set_our_sigflags(int sig, int flags) {
3141   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3142   if (sig > 0 && sig < NSIG) {
3143     sigflags[sig] = flags;
3144   }
3145 }
3146 
3147 void os::Aix::set_signal_handler(int sig, bool set_installed) {
3148   // Check for overwrite.
3149   struct sigaction oldAct;
3150   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3151 
3152   void* oldhand = oldAct.sa_sigaction
3153     ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3154     : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3155   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3156       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3157       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)javaSignalHandler)) {
3158     if (AllowUserSignalHandlers || !set_installed) {
3159       // Do not overwrite; user takes responsibility to forward to us.
3160       return;
3161     } else if (UseSignalChaining) {
3162       // save the old handler in jvm
3163       save_preinstalled_handler(sig, oldAct);
3164       // libjsig also interposes the sigaction() call below and saves the
3165       // old sigaction on it own.
3166     } else {
3167       fatal("Encountered unexpected pre-existing sigaction handler "
3168             "%#lx for signal %d.", (long)oldhand, sig);
3169     }
3170   }
3171 
3172   struct sigaction sigAct;
3173   sigfillset(&(sigAct.sa_mask));
3174   if (!set_installed) {
3175     sigAct.sa_handler = SIG_DFL;
3176     sigAct.sa_flags = SA_RESTART;
3177   } else {
3178     sigAct.sa_sigaction = javaSignalHandler;
3179     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3180   }
3181   // Save flags, which are set by ours
3182   assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
3183   sigflags[sig] = sigAct.sa_flags;
3184 
3185   int ret = sigaction(sig, &sigAct, &oldAct);
3186   assert(ret == 0, "check");
3187 
3188   void* oldhand2 = oldAct.sa_sigaction
3189                  ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3190                  : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3191   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3192 }
3193 
3194 // install signal handlers for signals that HotSpot needs to
3195 // handle in order to support Java-level exception handling.
3196 void os::Aix::install_signal_handlers() {
3197   if (!signal_handlers_are_installed) {
3198     signal_handlers_are_installed = true;
3199 
3200     // signal-chaining
3201     typedef void (*signal_setting_t)();
3202     signal_setting_t begin_signal_setting = NULL;
3203     signal_setting_t end_signal_setting = NULL;
3204     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3205                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3206     if (begin_signal_setting != NULL) {
3207       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3208                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3209       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3210                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3211       libjsig_is_loaded = true;
3212       assert(UseSignalChaining, "should enable signal-chaining");
3213     }
3214     if (libjsig_is_loaded) {
3215       // Tell libjsig jvm is setting signal handlers.
3216       (*begin_signal_setting)();
3217     }
3218 
3219     ::sigemptyset(&sigs);
3220     set_signal_handler(SIGSEGV, true);
3221     set_signal_handler(SIGPIPE, true);
3222     set_signal_handler(SIGBUS, true);
3223     set_signal_handler(SIGILL, true);
3224     set_signal_handler(SIGFPE, true);
3225     set_signal_handler(SIGTRAP, true);
3226     set_signal_handler(SIGXFSZ, true);
3227 
3228     if (libjsig_is_loaded) {
3229       // Tell libjsig jvm finishes setting signal handlers.
3230       (*end_signal_setting)();
3231     }
3232 
3233     // We don't activate signal checker if libjsig is in place, we trust ourselves
3234     // and if UserSignalHandler is installed all bets are off.
3235     // Log that signal checking is off only if -verbose:jni is specified.
3236     if (CheckJNICalls) {
3237       if (libjsig_is_loaded) {
3238         tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3239         check_signals = false;
3240       }
3241       if (AllowUserSignalHandlers) {
3242         tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3243         check_signals = false;
3244       }
3245       // Need to initialize check_signal_done.
3246       ::sigemptyset(&check_signal_done);
3247     }
3248   }
3249 }
3250 
3251 static const char* get_signal_handler_name(address handler,
3252                                            char* buf, int buflen) {
3253   int offset;
3254   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3255   if (found) {
3256     // skip directory names
3257     const char *p1, *p2;
3258     p1 = buf;
3259     size_t len = strlen(os::file_separator());
3260     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3261     // The way os::dll_address_to_library_name is implemented on Aix
3262     // right now, it always returns -1 for the offset which is not
3263     // terribly informative.
3264     // Will fix that. For now, omit the offset.
3265     jio_snprintf(buf, buflen, "%s", p1);
3266   } else {
3267     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3268   }
3269   return buf;
3270 }
3271 
3272 static void print_signal_handler(outputStream* st, int sig,
3273                                  char* buf, size_t buflen) {
3274   struct sigaction sa;
3275   sigaction(sig, NULL, &sa);
3276 
3277   st->print("%s: ", os::exception_name(sig, buf, buflen));
3278 
3279   address handler = (sa.sa_flags & SA_SIGINFO)
3280     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3281     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3282 
3283   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3284     st->print("SIG_DFL");
3285   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3286     st->print("SIG_IGN");
3287   } else {
3288     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3289   }
3290 
3291   // Print readable mask.
3292   st->print(", sa_mask[0]=");
3293   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3294 
3295   address rh = VMError::get_resetted_sighandler(sig);
3296   // May be, handler was resetted by VMError?
3297   if (rh != NULL) {
3298     handler = rh;
3299     sa.sa_flags = VMError::get_resetted_sigflags(sig);
3300   }
3301 
3302   // Print textual representation of sa_flags.
3303   st->print(", sa_flags=");
3304   os::Posix::print_sa_flags(st, sa.sa_flags);
3305 
3306   // Check: is it our handler?
3307   if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler) ||
3308       handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3309     // It is our signal handler.
3310     // Check for flags, reset system-used one!
3311     if ((int)sa.sa_flags != os::Aix::get_our_sigflags(sig)) {
3312       st->print(", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3313                 os::Aix::get_our_sigflags(sig));
3314     }
3315   }
3316   st->cr();
3317 }
3318 
3319 #define DO_SIGNAL_CHECK(sig) \
3320   if (!sigismember(&check_signal_done, sig)) \
3321     os::Aix::check_signal_handler(sig)
3322 
3323 // This method is a periodic task to check for misbehaving JNI applications
3324 // under CheckJNI, we can add any periodic checks here
3325 
3326 void os::run_periodic_checks() {
3327 
3328   if (check_signals == false) return;
3329 
3330   // SEGV and BUS if overridden could potentially prevent
3331   // generation of hs*.log in the event of a crash, debugging
3332   // such a case can be very challenging, so we absolutely
3333   // check the following for a good measure:
3334   DO_SIGNAL_CHECK(SIGSEGV);
3335   DO_SIGNAL_CHECK(SIGILL);
3336   DO_SIGNAL_CHECK(SIGFPE);
3337   DO_SIGNAL_CHECK(SIGBUS);
3338   DO_SIGNAL_CHECK(SIGPIPE);
3339   DO_SIGNAL_CHECK(SIGXFSZ);
3340   if (UseSIGTRAP) {
3341     DO_SIGNAL_CHECK(SIGTRAP);
3342   }
3343 
3344   // ReduceSignalUsage allows the user to override these handlers
3345   // see comments at the very top and jvm_md.h
3346   if (!ReduceSignalUsage) {
3347     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3348     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3349     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3350     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3351   }
3352 
3353   DO_SIGNAL_CHECK(SR_signum);
3354 }
3355 
3356 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3357 
3358 static os_sigaction_t os_sigaction = NULL;
3359 
3360 void os::Aix::check_signal_handler(int sig) {
3361   char buf[O_BUFLEN];
3362   address jvmHandler = NULL;
3363 
3364   struct sigaction act;
3365   if (os_sigaction == NULL) {
3366     // only trust the default sigaction, in case it has been interposed
3367     os_sigaction = CAST_TO_FN_PTR(os_sigaction_t, dlsym(RTLD_DEFAULT, "sigaction"));
3368     if (os_sigaction == NULL) return;
3369   }
3370 
3371   os_sigaction(sig, (struct sigaction*)NULL, &act);
3372 
3373   address thisHandler = (act.sa_flags & SA_SIGINFO)
3374     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3375     : CAST_FROM_FN_PTR(address, act.sa_handler);
3376 
3377   switch(sig) {
3378   case SIGSEGV:
3379   case SIGBUS:
3380   case SIGFPE:
3381   case SIGPIPE:
3382   case SIGILL:
3383   case SIGXFSZ:
3384     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)javaSignalHandler);
3385     break;
3386 
3387   case SHUTDOWN1_SIGNAL:
3388   case SHUTDOWN2_SIGNAL:
3389   case SHUTDOWN3_SIGNAL:
3390   case BREAK_SIGNAL:
3391     jvmHandler = (address)user_handler();
3392     break;
3393 
3394   default:
3395     if (sig == SR_signum) {
3396       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3397     } else {
3398       return;
3399     }
3400     break;
3401   }
3402 
3403   if (thisHandler != jvmHandler) {
3404     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3405     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3406     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3407     // No need to check this sig any longer
3408     sigaddset(&check_signal_done, sig);
3409     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3410     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3411       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3412                     exception_name(sig, buf, O_BUFLEN));
3413     }
3414   } else if (os::Aix::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Aix::get_our_sigflags(sig)) {
3415     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3416     tty->print("expected:");
3417     os::Posix::print_sa_flags(tty, os::Aix::get_our_sigflags(sig));
3418     tty->cr();
3419     tty->print("  found:");
3420     os::Posix::print_sa_flags(tty, act.sa_flags);
3421     tty->cr();
3422     // No need to check this sig any longer
3423     sigaddset(&check_signal_done, sig);
3424   }
3425 
3426   // Dump all the signal
3427   if (sigismember(&check_signal_done, sig)) {
3428     print_signal_handlers(tty, buf, O_BUFLEN);
3429   }
3430 }
3431 
3432 // To install functions for atexit system call
3433 extern "C" {
3434   static void perfMemory_exit_helper() {
3435     perfMemory_exit();
3436   }
3437 }
3438 
3439 // This is called _before_ the most of global arguments have been parsed.
3440 void os::init(void) {
3441   // This is basic, we want to know if that ever changes.
3442   // (Shared memory boundary is supposed to be a 256M aligned.)
3443   assert(SHMLBA == ((uint64_t)0x10000000ULL)/*256M*/, "unexpected");
3444 
3445   // Record process break at startup.
3446   g_brk_at_startup = (address) ::sbrk(0);
3447   assert(g_brk_at_startup != (address) -1, "sbrk failed");
3448 
3449   // First off, we need to know whether we run on AIX or PASE, and
3450   // the OS level we run on.
3451   os::Aix::initialize_os_info();
3452 
3453   // Scan environment (SPEC1170 behaviour, etc).
3454   os::Aix::scan_environment();
3455 
3456   // Probe multipage support.
3457   query_multipage_support();
3458 
3459   // Act like we only have one page size by eliminating corner cases which
3460   // we did not support very well anyway.
3461   // We have two input conditions:
3462   // 1) Data segment page size. This is controlled by linker setting (datapsize) on the
3463   //    launcher, and/or by LDR_CNTRL environment variable. The latter overrules the linker
3464   //    setting.
3465   //    Data segment page size is important for us because it defines the thread stack page
3466   //    size, which is needed for guard page handling, stack banging etc.
3467   // 2) The ability to allocate 64k pages dynamically. If this is a given, java heap can
3468   //    and should be allocated with 64k pages.
3469   //
3470   // So, we do the following:
3471   // LDR_CNTRL    can_use_64K_pages_dynamically       what we do                      remarks
3472   // 4K           no                                  4K                              old systems (aix 5.2, as/400 v5r4) or new systems with AME activated
3473   // 4k           yes                                 64k (treat 4k stacks as 64k)    different loader than java and standard settings
3474   // 64k          no              --- AIX 5.2 ? ---
3475   // 64k          yes                                 64k                             new systems and standard java loader (we set datapsize=64k when linking)
3476 
3477   // We explicitly leave no option to change page size, because only upgrading would work,
3478   // not downgrading (if stack page size is 64k you cannot pretend its 4k).
3479 
3480   if (g_multipage_support.datapsize == 4*K) {
3481     // datapsize = 4K. Data segment, thread stacks are 4K paged.
3482     if (g_multipage_support.can_use_64K_pages) {
3483       // .. but we are able to use 64K pages dynamically.
3484       // This would be typical for java launchers which are not linked
3485       // with datapsize=64K (like, any other launcher but our own).
3486       //
3487       // In this case it would be smart to allocate the java heap with 64K
3488       // to get the performance benefit, and to fake 64k pages for the
3489       // data segment (when dealing with thread stacks).
3490       //
3491       // However, leave a possibility to downgrade to 4K, using
3492       // -XX:-Use64KPages.
3493       if (Use64KPages) {
3494         trcVerbose("64K page mode (faked for data segment)");
3495         Aix::_page_size = 64*K;
3496       } else {
3497         trcVerbose("4K page mode (Use64KPages=off)");
3498         Aix::_page_size = 4*K;
3499       }
3500     } else {
3501       // .. and not able to allocate 64k pages dynamically. Here, just
3502       // fall back to 4K paged mode and use mmap for everything.
3503       trcVerbose("4K page mode");
3504       Aix::_page_size = 4*K;
3505       FLAG_SET_ERGO(bool, Use64KPages, false);
3506     }
3507   } else {
3508     // datapsize = 64k. Data segment, thread stacks are 64k paged.
3509     // This normally means that we can allocate 64k pages dynamically.
3510     // (There is one special case where this may be false: EXTSHM=on.
3511     // but we decided to not support that mode).
3512     assert0(g_multipage_support.can_use_64K_pages);
3513     Aix::_page_size = 64*K;
3514     trcVerbose("64K page mode");
3515     FLAG_SET_ERGO(bool, Use64KPages, true);
3516   }
3517 
3518   // For now UseLargePages is just ignored.
3519   FLAG_SET_ERGO(bool, UseLargePages, false);
3520   _page_sizes[0] = 0;
3521 
3522   // debug trace
3523   trcVerbose("os::vm_page_size %s", describe_pagesize(os::vm_page_size()));
3524 
3525   // Next, we need to initialize libo4 and libperfstat libraries.
3526   if (os::Aix::on_pase()) {
3527     os::Aix::initialize_libo4();
3528   } else {
3529     os::Aix::initialize_libperfstat();
3530   }
3531 
3532   // Reset the perfstat information provided by ODM.
3533   if (os::Aix::on_aix()) {
3534     libperfstat::perfstat_reset();
3535   }
3536 
3537   // Now initialze basic system properties. Note that for some of the values we
3538   // need libperfstat etc.
3539   os::Aix::initialize_system_info();
3540 
3541   clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3542 
3543   init_random(1234567);
3544 
3545   // _main_thread points to the thread that created/loaded the JVM.
3546   Aix::_main_thread = pthread_self();
3547 
3548   initial_time_count = os::elapsed_counter();
3549 
3550   os::Posix::init();
3551 }
3552 
3553 // This is called _after_ the global arguments have been parsed.
3554 jint os::init_2(void) {
3555 
3556   os::Posix::init_2();
3557 
3558   if (os::Aix::on_pase()) {
3559     trcVerbose("Running on PASE.");
3560   } else {
3561     trcVerbose("Running on AIX (not PASE).");
3562   }
3563 
3564   trcVerbose("processor count: %d", os::_processor_count);
3565   trcVerbose("physical memory: %lu", Aix::_physical_memory);
3566 
3567   // Initially build up the loaded dll map.
3568   LoadedLibraries::reload();
3569   if (Verbose) {
3570     trcVerbose("Loaded Libraries: ");
3571     LoadedLibraries::print(tty);
3572   }
3573 
3574   // initialize suspend/resume support - must do this before signal_sets_init()
3575   if (SR_initialize() != 0) {
3576     perror("SR_initialize failed");
3577     return JNI_ERR;
3578   }
3579 
3580   Aix::signal_sets_init();
3581   Aix::install_signal_handlers();
3582 
3583   // Check and sets minimum stack sizes against command line options
3584   if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
3585     return JNI_ERR;
3586   }
3587 
3588   if (UseNUMA) {
3589     UseNUMA = false;
3590     warning("NUMA optimizations are not available on this OS.");
3591   }
3592 
3593   if (MaxFDLimit) {
3594     // Set the number of file descriptors to max. print out error
3595     // if getrlimit/setrlimit fails but continue regardless.
3596     struct rlimit nbr_files;
3597     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3598     if (status != 0) {
3599       log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
3600     } else {
3601       nbr_files.rlim_cur = nbr_files.rlim_max;
3602       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3603       if (status != 0) {
3604         log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
3605       }
3606     }
3607   }
3608 
3609   if (PerfAllowAtExitRegistration) {
3610     // Only register atexit functions if PerfAllowAtExitRegistration is set.
3611     // At exit functions can be delayed until process exit time, which
3612     // can be problematic for embedded VM situations. Embedded VMs should
3613     // call DestroyJavaVM() to assure that VM resources are released.
3614 
3615     // Note: perfMemory_exit_helper atexit function may be removed in
3616     // the future if the appropriate cleanup code can be added to the
3617     // VM_Exit VMOperation's doit method.
3618     if (atexit(perfMemory_exit_helper) != 0) {
3619       warning("os::init_2 atexit(perfMemory_exit_helper) failed");
3620     }
3621   }
3622 
3623   return JNI_OK;
3624 }
3625 
3626 // Mark the polling page as unreadable
3627 void os::make_polling_page_unreadable(void) {
3628   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
3629     fatal("Could not disable polling page");
3630   }
3631 };
3632 
3633 // Mark the polling page as readable
3634 void os::make_polling_page_readable(void) {
3635   // Changed according to os_linux.cpp.
3636   if (!checked_mprotect((char *)_polling_page, Aix::page_size(), PROT_READ)) {
3637     fatal("Could not enable polling page at " PTR_FORMAT, _polling_page);
3638   }
3639 };
3640 
3641 int os::active_processor_count() {
3642   // User has overridden the number of active processors
3643   if (ActiveProcessorCount > 0) {
3644     log_trace(os)("active_processor_count: "
3645                   "active processor count set by user : %d",
3646                   ActiveProcessorCount);
3647     return ActiveProcessorCount;
3648   }
3649 
3650   int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3651   assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3652   return online_cpus;
3653 }
3654 
3655 void os::set_native_thread_name(const char *name) {
3656   // Not yet implemented.
3657   return;
3658 }
3659 
3660 bool os::distribute_processes(uint length, uint* distribution) {
3661   // Not yet implemented.
3662   return false;
3663 }
3664 
3665 bool os::bind_to_processor(uint processor_id) {
3666   // Not yet implemented.
3667   return false;
3668 }
3669 
3670 void os::SuspendedThreadTask::internal_do_task() {
3671   if (do_suspend(_thread->osthread())) {
3672     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3673     do_task(context);
3674     do_resume(_thread->osthread());
3675   }
3676 }
3677 
3678 ////////////////////////////////////////////////////////////////////////////////
3679 // debug support
3680 
3681 bool os::find(address addr, outputStream* st) {
3682 
3683   st->print(PTR_FORMAT ": ", addr);
3684 
3685   loaded_module_t lm;
3686   if (LoadedLibraries::find_for_text_address(addr, &lm) != NULL ||
3687       LoadedLibraries::find_for_data_address(addr, &lm) != NULL) {
3688     st->print_cr("%s", lm.path);
3689     return true;
3690   }
3691 
3692   return false;
3693 }
3694 
3695 ////////////////////////////////////////////////////////////////////////////////
3696 // misc
3697 
3698 // This does not do anything on Aix. This is basically a hook for being
3699 // able to use structured exception handling (thread-local exception filters)
3700 // on, e.g., Win32.
3701 void
3702 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
3703                          JavaCallArguments* args, Thread* thread) {
3704   f(value, method, args, thread);
3705 }
3706 
3707 void os::print_statistics() {
3708 }
3709 
3710 bool os::message_box(const char* title, const char* message) {
3711   int i;
3712   fdStream err(defaultStream::error_fd());
3713   for (i = 0; i < 78; i++) err.print_raw("=");
3714   err.cr();
3715   err.print_raw_cr(title);
3716   for (i = 0; i < 78; i++) err.print_raw("-");
3717   err.cr();
3718   err.print_raw_cr(message);
3719   for (i = 0; i < 78; i++) err.print_raw("=");
3720   err.cr();
3721 
3722   char buf[16];
3723   // Prevent process from exiting upon "read error" without consuming all CPU
3724   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3725 
3726   return buf[0] == 'y' || buf[0] == 'Y';
3727 }
3728 
3729 int os::stat(const char *path, struct stat *sbuf) {
3730   char pathbuf[MAX_PATH];
3731   if (strlen(path) > MAX_PATH - 1) {
3732     errno = ENAMETOOLONG;
3733     return -1;
3734   }
3735   os::native_path(strcpy(pathbuf, path));
3736   return ::stat(pathbuf, sbuf);
3737 }
3738 
3739 // Is a (classpath) directory empty?
3740 bool os::dir_is_empty(const char* path) {
3741   DIR *dir = NULL;
3742   struct dirent *ptr;
3743 
3744   dir = opendir(path);
3745   if (dir == NULL) return true;
3746 
3747   /* Scan the directory */
3748   bool result = true;
3749   char buf[sizeof(struct dirent) + MAX_PATH];
3750   while (result && (ptr = ::readdir(dir)) != NULL) {
3751     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3752       result = false;
3753     }
3754   }
3755   closedir(dir);
3756   return result;
3757 }
3758 
3759 // This code originates from JDK's sysOpen and open64_w
3760 // from src/solaris/hpi/src/system_md.c
3761 
3762 int os::open(const char *path, int oflag, int mode) {
3763 
3764   if (strlen(path) > MAX_PATH - 1) {
3765     errno = ENAMETOOLONG;
3766     return -1;
3767   }
3768   int fd;
3769 
3770   fd = ::open64(path, oflag, mode);
3771   if (fd == -1) return -1;
3772 
3773   // If the open succeeded, the file might still be a directory.
3774   {
3775     struct stat64 buf64;
3776     int ret = ::fstat64(fd, &buf64);
3777     int st_mode = buf64.st_mode;
3778 
3779     if (ret != -1) {
3780       if ((st_mode & S_IFMT) == S_IFDIR) {
3781         errno = EISDIR;
3782         ::close(fd);
3783         return -1;
3784       }
3785     } else {
3786       ::close(fd);
3787       return -1;
3788     }
3789   }
3790 
3791   // All file descriptors that are opened in the JVM and not
3792   // specifically destined for a subprocess should have the
3793   // close-on-exec flag set. If we don't set it, then careless 3rd
3794   // party native code might fork and exec without closing all
3795   // appropriate file descriptors (e.g. as we do in closeDescriptors in
3796   // UNIXProcess.c), and this in turn might:
3797   //
3798   // - cause end-of-file to fail to be detected on some file
3799   //   descriptors, resulting in mysterious hangs, or
3800   //
3801   // - might cause an fopen in the subprocess to fail on a system
3802   //   suffering from bug 1085341.
3803   //
3804   // (Yes, the default setting of the close-on-exec flag is a Unix
3805   // design flaw.)
3806   //
3807   // See:
3808   // 1085341: 32-bit stdio routines should support file descriptors >255
3809   // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
3810   // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
3811 #ifdef FD_CLOEXEC
3812   {
3813     int flags = ::fcntl(fd, F_GETFD);
3814     if (flags != -1)
3815       ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
3816   }
3817 #endif
3818 
3819   return fd;
3820 }
3821 
3822 // create binary file, rewriting existing file if required
3823 int os::create_binary_file(const char* path, bool rewrite_existing) {
3824   int oflags = O_WRONLY | O_CREAT;
3825   if (!rewrite_existing) {
3826     oflags |= O_EXCL;
3827   }
3828   return ::open64(path, oflags, S_IREAD | S_IWRITE);
3829 }
3830 
3831 // return current position of file pointer
3832 jlong os::current_file_offset(int fd) {
3833   return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
3834 }
3835 
3836 // move file pointer to the specified offset
3837 jlong os::seek_to_file_offset(int fd, jlong offset) {
3838   return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
3839 }
3840 
3841 // This code originates from JDK's sysAvailable
3842 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
3843 
3844 int os::available(int fd, jlong *bytes) {
3845   jlong cur, end;
3846   int mode;
3847   struct stat64 buf64;
3848 
3849   if (::fstat64(fd, &buf64) >= 0) {
3850     mode = buf64.st_mode;
3851     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
3852       int n;
3853       if (::ioctl(fd, FIONREAD, &n) >= 0) {
3854         *bytes = n;
3855         return 1;
3856       }
3857     }
3858   }
3859   if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
3860     return 0;
3861   } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
3862     return 0;
3863   } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
3864     return 0;
3865   }
3866   *bytes = end - cur;
3867   return 1;
3868 }
3869 
3870 // Map a block of memory.
3871 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
3872                         char *addr, size_t bytes, bool read_only,
3873                         bool allow_exec) {
3874   int prot;
3875   int flags = MAP_PRIVATE;
3876 
3877   if (read_only) {
3878     prot = PROT_READ;
3879     flags = MAP_SHARED;
3880   } else {
3881     prot = PROT_READ | PROT_WRITE;
3882     flags = MAP_PRIVATE;
3883   }
3884 
3885   if (allow_exec) {
3886     prot |= PROT_EXEC;
3887   }
3888 
3889   if (addr != NULL) {
3890     flags |= MAP_FIXED;
3891   }
3892 
3893   // Allow anonymous mappings if 'fd' is -1.
3894   if (fd == -1) {
3895     flags |= MAP_ANONYMOUS;
3896   }
3897 
3898   char* mapped_address = (char*)::mmap(addr, (size_t)bytes, prot, flags,
3899                                      fd, file_offset);
3900   if (mapped_address == MAP_FAILED) {
3901     return NULL;
3902   }
3903   return mapped_address;
3904 }
3905 
3906 // Remap a block of memory.
3907 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
3908                           char *addr, size_t bytes, bool read_only,
3909                           bool allow_exec) {
3910   // same as map_memory() on this OS
3911   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
3912                         allow_exec);
3913 }
3914 
3915 // Unmap a block of memory.
3916 bool os::pd_unmap_memory(char* addr, size_t bytes) {
3917   return munmap(addr, bytes) == 0;
3918 }
3919 
3920 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
3921 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
3922 // of a thread.
3923 //
3924 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
3925 // the fast estimate available on the platform.
3926 
3927 jlong os::current_thread_cpu_time() {
3928   // return user + sys since the cost is the same
3929   const jlong n = os::thread_cpu_time(Thread::current(), true /* user + sys */);
3930   assert(n >= 0, "negative CPU time");
3931   return n;
3932 }
3933 
3934 jlong os::thread_cpu_time(Thread* thread) {
3935   // consistent with what current_thread_cpu_time() returns
3936   const jlong n = os::thread_cpu_time(thread, true /* user + sys */);
3937   assert(n >= 0, "negative CPU time");
3938   return n;
3939 }
3940 
3941 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
3942   const jlong n = os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
3943   assert(n >= 0, "negative CPU time");
3944   return n;
3945 }
3946 
3947 static bool thread_cpu_time_unchecked(Thread* thread, jlong* p_sys_time, jlong* p_user_time) {
3948   bool error = false;
3949 
3950   jlong sys_time = 0;
3951   jlong user_time = 0;
3952 
3953   // Reimplemented using getthrds64().
3954   //
3955   // Works like this:
3956   // For the thread in question, get the kernel thread id. Then get the
3957   // kernel thread statistics using that id.
3958   //
3959   // This only works of course when no pthread scheduling is used,
3960   // i.e. there is a 1:1 relationship to kernel threads.
3961   // On AIX, see AIXTHREAD_SCOPE variable.
3962 
3963   pthread_t pthtid = thread->osthread()->pthread_id();
3964 
3965   // retrieve kernel thread id for the pthread:
3966   tid64_t tid = 0;
3967   struct __pthrdsinfo pinfo;
3968   // I just love those otherworldly IBM APIs which force me to hand down
3969   // dummy buffers for stuff I dont care for...
3970   char dummy[1];
3971   int dummy_size = sizeof(dummy);
3972   if (pthread_getthrds_np(&pthtid, PTHRDSINFO_QUERY_TID, &pinfo, sizeof(pinfo),
3973                           dummy, &dummy_size) == 0) {
3974     tid = pinfo.__pi_tid;
3975   } else {
3976     tty->print_cr("pthread_getthrds_np failed.");
3977     error = true;
3978   }
3979 
3980   // retrieve kernel timing info for that kernel thread
3981   if (!error) {
3982     struct thrdentry64 thrdentry;
3983     if (getthrds64(getpid(), &thrdentry, sizeof(thrdentry), &tid, 1) == 1) {
3984       sys_time = thrdentry.ti_ru.ru_stime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_stime.tv_usec * 1000LL;
3985       user_time = thrdentry.ti_ru.ru_utime.tv_sec * 1000000000LL + thrdentry.ti_ru.ru_utime.tv_usec * 1000LL;
3986     } else {
3987       tty->print_cr("pthread_getthrds_np failed.");
3988       error = true;
3989     }
3990   }
3991 
3992   if (p_sys_time) {
3993     *p_sys_time = sys_time;
3994   }
3995 
3996   if (p_user_time) {
3997     *p_user_time = user_time;
3998   }
3999 
4000   if (error) {
4001     return false;
4002   }
4003 
4004   return true;
4005 }
4006 
4007 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4008   jlong sys_time;
4009   jlong user_time;
4010 
4011   if (!thread_cpu_time_unchecked(thread, &sys_time, &user_time)) {
4012     return -1;
4013   }
4014 
4015   return user_sys_cpu_time ? sys_time + user_time : user_time;
4016 }
4017 
4018 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4019   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4020   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4021   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4022   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4023 }
4024 
4025 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4026   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4027   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4028   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4029   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4030 }
4031 
4032 bool os::is_thread_cpu_time_supported() {
4033   return true;
4034 }
4035 
4036 // System loadavg support. Returns -1 if load average cannot be obtained.
4037 // For now just return the system wide load average (no processor sets).
4038 int os::loadavg(double values[], int nelem) {
4039 
4040   guarantee(nelem >= 0 && nelem <= 3, "argument error");
4041   guarantee(values, "argument error");
4042 
4043   if (os::Aix::on_pase()) {
4044 
4045     // AS/400 PASE: use libo4 porting library
4046     double v[3] = { 0.0, 0.0, 0.0 };
4047 
4048     if (libo4::get_load_avg(v, v + 1, v + 2)) {
4049       for (int i = 0; i < nelem; i ++) {
4050         values[i] = v[i];
4051       }
4052       return nelem;
4053     } else {
4054       return -1;
4055     }
4056 
4057   } else {
4058 
4059     // AIX: use libperfstat
4060     libperfstat::cpuinfo_t ci;
4061     if (libperfstat::get_cpuinfo(&ci)) {
4062       for (int i = 0; i < nelem; i++) {
4063         values[i] = ci.loadavg[i];
4064       }
4065     } else {
4066       return -1;
4067     }
4068     return nelem;
4069   }
4070 }
4071 
4072 void os::pause() {
4073   char filename[MAX_PATH];
4074   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4075     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4076   } else {
4077     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4078   }
4079 
4080   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4081   if (fd != -1) {
4082     struct stat buf;
4083     ::close(fd);
4084     while (::stat(filename, &buf) == 0) {
4085       (void)::poll(NULL, 0, 100);
4086     }
4087   } else {
4088     trcVerbose("Could not open pause file '%s', continuing immediately.", filename);
4089   }
4090 }
4091 
4092 bool os::is_primordial_thread(void) {
4093   if (pthread_self() == (pthread_t)1) {
4094     return true;
4095   } else {
4096     return false;
4097   }
4098 }
4099 
4100 // OS recognitions (PASE/AIX, OS level) call this before calling any
4101 // one of Aix::on_pase(), Aix::os_version() static
4102 void os::Aix::initialize_os_info() {
4103 
4104   assert(_on_pase == -1 && _os_version == 0, "already called.");
4105 
4106   struct utsname uts;
4107   memset(&uts, 0, sizeof(uts));
4108   strcpy(uts.sysname, "?");
4109   if (::uname(&uts) == -1) {
4110     trcVerbose("uname failed (%d)", errno);
4111     guarantee(0, "Could not determine whether we run on AIX or PASE");
4112   } else {
4113     trcVerbose("uname says: sysname \"%s\" version \"%s\" release \"%s\" "
4114                "node \"%s\" machine \"%s\"\n",
4115                uts.sysname, uts.version, uts.release, uts.nodename, uts.machine);
4116     const int major = atoi(uts.version);
4117     assert(major > 0, "invalid OS version");
4118     const int minor = atoi(uts.release);
4119     assert(minor > 0, "invalid OS release");
4120     _os_version = (major << 24) | (minor << 16);
4121     char ver_str[20] = {0};
4122     char *name_str = "unknown OS";
4123     if (strcmp(uts.sysname, "OS400") == 0) {
4124       // We run on AS/400 PASE. We do not support versions older than V5R4M0.
4125       _on_pase = 1;
4126       if (os_version_short() < 0x0504) {
4127         trcVerbose("OS/400 releases older than V5R4M0 not supported.");
4128         assert(false, "OS/400 release too old.");
4129       }
4130       name_str = "OS/400 (pase)";
4131       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u", major, minor);
4132     } else if (strcmp(uts.sysname, "AIX") == 0) {
4133       // We run on AIX. We do not support versions older than AIX 5.3.
4134       _on_pase = 0;
4135       // Determine detailed AIX version: Version, Release, Modification, Fix Level.
4136       odmWrapper::determine_os_kernel_version(&_os_version);
4137       if (os_version_short() < 0x0503) {
4138         trcVerbose("AIX release older than AIX 5.3 not supported.");
4139         assert(false, "AIX release too old.");
4140       }
4141       name_str = "AIX";
4142       jio_snprintf(ver_str, sizeof(ver_str), "%u.%u.%u.%u",
4143                    major, minor, (_os_version >> 8) & 0xFF, _os_version & 0xFF);
4144     } else {
4145       assert(false, name_str);
4146     }
4147     trcVerbose("We run on %s %s", name_str, ver_str);
4148   }
4149 
4150   guarantee(_on_pase != -1 && _os_version, "Could not determine AIX/OS400 release");
4151 } // end: os::Aix::initialize_os_info()
4152 
4153 // Scan environment for important settings which might effect the VM.
4154 // Trace out settings. Warn about invalid settings and/or correct them.
4155 //
4156 // Must run after os::Aix::initialue_os_info().
4157 void os::Aix::scan_environment() {
4158 
4159   char* p;
4160   int rc;
4161 
4162   // Warn explicity if EXTSHM=ON is used. That switch changes how
4163   // System V shared memory behaves. One effect is that page size of
4164   // shared memory cannot be change dynamically, effectivly preventing
4165   // large pages from working.
4166   // This switch was needed on AIX 32bit, but on AIX 64bit the general
4167   // recommendation is (in OSS notes) to switch it off.
4168   p = ::getenv("EXTSHM");
4169   trcVerbose("EXTSHM=%s.", p ? p : "<unset>");
4170   if (p && strcasecmp(p, "ON") == 0) {
4171     _extshm = 1;
4172     trcVerbose("*** Unsupported mode! Please remove EXTSHM from your environment! ***");
4173     if (!AllowExtshm) {
4174       // We allow under certain conditions the user to continue. However, we want this
4175       // to be a fatal error by default. On certain AIX systems, leaving EXTSHM=ON means
4176       // that the VM is not able to allocate 64k pages for the heap.
4177       // We do not want to run with reduced performance.
4178       vm_exit_during_initialization("EXTSHM is ON. Please remove EXTSHM from your environment.");
4179     }
4180   } else {
4181     _extshm = 0;
4182   }
4183 
4184   // SPEC1170 behaviour: will change the behaviour of a number of POSIX APIs.
4185   // Not tested, not supported.
4186   //
4187   // Note that it might be worth the trouble to test and to require it, if only to
4188   // get useful return codes for mprotect.
4189   //
4190   // Note: Setting XPG_SUS_ENV in the process is too late. Must be set earlier (before
4191   // exec() ? before loading the libjvm ? ....)
4192   p = ::getenv("XPG_SUS_ENV");
4193   trcVerbose("XPG_SUS_ENV=%s.", p ? p : "<unset>");
4194   if (p && strcmp(p, "ON") == 0) {
4195     _xpg_sus_mode = 1;
4196     trcVerbose("Unsupported setting: XPG_SUS_ENV=ON");
4197     // This is not supported. Worst of all, it changes behaviour of mmap MAP_FIXED to
4198     // clobber address ranges. If we ever want to support that, we have to do some
4199     // testing first.
4200     guarantee(false, "XPG_SUS_ENV=ON not supported");
4201   } else {
4202     _xpg_sus_mode = 0;
4203   }
4204 
4205   if (os::Aix::on_pase()) {
4206     p = ::getenv("QIBM_MULTI_THREADED");
4207     trcVerbose("QIBM_MULTI_THREADED=%s.", p ? p : "<unset>");
4208   }
4209 
4210   p = ::getenv("LDR_CNTRL");
4211   trcVerbose("LDR_CNTRL=%s.", p ? p : "<unset>");
4212   if (os::Aix::on_pase() && os::Aix::os_version_short() == 0x0701) {
4213     if (p && ::strstr(p, "TEXTPSIZE")) {
4214       trcVerbose("*** WARNING - LDR_CNTRL contains TEXTPSIZE. "
4215         "you may experience hangs or crashes on OS/400 V7R1.");
4216     }
4217   }
4218 
4219   p = ::getenv("AIXTHREAD_GUARDPAGES");
4220   trcVerbose("AIXTHREAD_GUARDPAGES=%s.", p ? p : "<unset>");
4221 
4222 } // end: os::Aix::scan_environment()
4223 
4224 // PASE: initialize the libo4 library (PASE porting library).
4225 void os::Aix::initialize_libo4() {
4226   guarantee(os::Aix::on_pase(), "OS/400 only.");
4227   if (!libo4::init()) {
4228     trcVerbose("libo4 initialization failed.");
4229     assert(false, "libo4 initialization failed");
4230   } else {
4231     trcVerbose("libo4 initialized.");
4232   }
4233 }
4234 
4235 // AIX: initialize the libperfstat library.
4236 void os::Aix::initialize_libperfstat() {
4237   assert(os::Aix::on_aix(), "AIX only");
4238   if (!libperfstat::init()) {
4239     trcVerbose("libperfstat initialization failed.");
4240     assert(false, "libperfstat initialization failed");
4241   } else {
4242     trcVerbose("libperfstat initialized.");
4243   }
4244 }
4245 
4246 /////////////////////////////////////////////////////////////////////////////
4247 // thread stack
4248 
4249 // Get the current stack base from the OS (actually, the pthread library).
4250 // Note: usually not page aligned.
4251 address os::current_stack_base() {
4252   AixMisc::stackbounds_t bounds;
4253   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4254   guarantee(rc, "Unable to retrieve stack bounds.");
4255   return bounds.base;
4256 }
4257 
4258 // Get the current stack size from the OS (actually, the pthread library).
4259 // Returned size is such that (base - size) is always aligned to page size.
4260 size_t os::current_stack_size() {
4261   AixMisc::stackbounds_t bounds;
4262   bool rc = AixMisc::query_stack_bounds_for_current_thread(&bounds);
4263   guarantee(rc, "Unable to retrieve stack bounds.");
4264   // Align the returned stack size such that the stack low address
4265   // is aligned to page size (Note: base is usually not and we do not care).
4266   // We need to do this because caller code will assume stack low address is
4267   // page aligned and will place guard pages without checking.
4268   address low = bounds.base - bounds.size;
4269   address low_aligned = (address)align_up(low, os::vm_page_size());
4270   size_t s = bounds.base - low_aligned;
4271   return s;
4272 }
4273 
4274 extern char** environ;
4275 
4276 // Run the specified command in a separate process. Return its exit value,
4277 // or -1 on failure (e.g. can't fork a new process).
4278 // Unlike system(), this function can be called from signal handler. It
4279 // doesn't block SIGINT et al.
4280 int os::fork_and_exec(char* cmd) {
4281   char * argv[4] = {"sh", "-c", cmd, NULL};
4282 
4283   pid_t pid = fork();
4284 
4285   if (pid < 0) {
4286     // fork failed
4287     return -1;
4288 
4289   } else if (pid == 0) {
4290     // child process
4291 
4292     // Try to be consistent with system(), which uses "/usr/bin/sh" on AIX.
4293     execve("/usr/bin/sh", argv, environ);
4294 
4295     // execve failed
4296     _exit(-1);
4297 
4298   } else {
4299     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4300     // care about the actual exit code, for now.
4301 
4302     int status;
4303 
4304     // Wait for the child process to exit. This returns immediately if
4305     // the child has already exited. */
4306     while (waitpid(pid, &status, 0) < 0) {
4307       switch (errno) {
4308         case ECHILD: return 0;
4309         case EINTR: break;
4310         default: return -1;
4311       }
4312     }
4313 
4314     if (WIFEXITED(status)) {
4315       // The child exited normally; get its exit code.
4316       return WEXITSTATUS(status);
4317     } else if (WIFSIGNALED(status)) {
4318       // The child exited because of a signal.
4319       // The best value to return is 0x80 + signal number,
4320       // because that is what all Unix shells do, and because
4321       // it allows callers to distinguish between process exit and
4322       // process death by signal.
4323       return 0x80 + WTERMSIG(status);
4324     } else {
4325       // Unknown exit code; pass it through.
4326       return status;
4327     }
4328   }
4329   return -1;
4330 }
4331 
4332 // Get the default path to the core file
4333 // Returns the length of the string
4334 int os::get_core_path(char* buffer, size_t bufferSize) {
4335   const char* p = get_current_directory(buffer, bufferSize);
4336 
4337   if (p == NULL) {
4338     assert(p != NULL, "failed to get current directory");
4339     return 0;
4340   }
4341 
4342   jio_snprintf(buffer, bufferSize, "%s/core or core.%d",
4343                                                p, current_process_id());
4344 
4345   return strlen(buffer);
4346 }
4347 
4348 #ifndef PRODUCT
4349 void TestReserveMemorySpecial_test() {
4350   // No tests available for this platform
4351 }
4352 #endif
4353 
4354 bool os::start_debugging(char *buf, int buflen) {
4355   int len = (int)strlen(buf);
4356   char *p = &buf[len];
4357 
4358   jio_snprintf(p, buflen -len,
4359                  "\n\n"
4360                  "Do you want to debug the problem?\n\n"
4361                  "To debug, run 'dbx -a %d'; then switch to thread tid " INTX_FORMAT ", k-tid " INTX_FORMAT "\n"
4362                  "Enter 'yes' to launch dbx automatically (PATH must include dbx)\n"
4363                  "Otherwise, press RETURN to abort...",
4364                  os::current_process_id(),
4365                  os::current_thread_id(), thread_self());
4366 
4367   bool yes = os::message_box("Unexpected Error", buf);
4368 
4369   if (yes) {
4370     // yes, user asked VM to launch debugger
4371     jio_snprintf(buf, buflen, "dbx -a %d", os::current_process_id());
4372 
4373     os::fork_and_exec(buf);
4374     yes = false;
4375   }
4376   return yes;
4377 }
4378 
4379 static inline time_t get_mtime(const char* filename) {
4380   struct stat st;
4381   int ret = os::stat(filename, &st);
4382   assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
4383   return st.st_mtime;
4384 }
4385 
4386 int os::compare_file_modified_times(const char* file1, const char* file2) {
4387   time_t t1 = get_mtime(file1);
4388   time_t t2 = get_mtime(file2);
4389   return t1 - t2;
4390 }