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