1 /* 2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 // no precompiled headers 26 #include "classfile/classLoader.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "code/vtableStubs.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "compiler/disassembler.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "jvm_linux.h" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "memory/filemap.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "os_linux.inline.hpp" 40 #include "os_share_linux.hpp" 41 #include "prims/jniFastGetField.hpp" 42 #include "prims/jvm.h" 43 #include "prims/jvm_misc.hpp" 44 #include "runtime/arguments.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/extendedPC.hpp" 47 #include "runtime/globals.hpp" 48 #include "runtime/interfaceSupport.hpp" 49 #include "runtime/init.hpp" 50 #include "runtime/java.hpp" 51 #include "runtime/javaCalls.hpp" 52 #include "runtime/mutexLocker.hpp" 53 #include "runtime/objectMonitor.hpp" 54 #include "runtime/orderAccess.inline.hpp" 55 #include "runtime/osThread.hpp" 56 #include "runtime/perfMemory.hpp" 57 #include "runtime/sharedRuntime.hpp" 58 #include "runtime/statSampler.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/thread.inline.hpp" 61 #include "runtime/threadCritical.hpp" 62 #include "runtime/timer.hpp" 63 #include "semaphore_posix.hpp" 64 #include "services/attachListener.hpp" 65 #include "services/memTracker.hpp" 66 #include "services/runtimeService.hpp" 67 #include "utilities/decoder.hpp" 68 #include "utilities/defaultStream.hpp" 69 #include "utilities/events.hpp" 70 #include "utilities/elfFile.hpp" 71 #include "utilities/growableArray.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/vmError.hpp" 74 75 // put OS-includes here 76 # include <sys/types.h> 77 # include <sys/mman.h> 78 # include <sys/stat.h> 79 # include <sys/select.h> 80 # include <pthread.h> 81 # include <signal.h> 82 # include <errno.h> 83 # include <dlfcn.h> 84 # include <stdio.h> 85 # include <unistd.h> 86 # include <sys/resource.h> 87 # include <pthread.h> 88 # include <sys/stat.h> 89 # include <sys/time.h> 90 # include <sys/times.h> 91 # include <sys/utsname.h> 92 # include <sys/socket.h> 93 # include <sys/wait.h> 94 # include <pwd.h> 95 # include <poll.h> 96 # include <semaphore.h> 97 # include <fcntl.h> 98 # include <string.h> 99 # include <syscall.h> 100 # include <sys/sysinfo.h> 101 # include <sys/ipc.h> 102 # include <sys/shm.h> 103 # include <link.h> 104 # include <stdint.h> 105 # include <inttypes.h> 106 # include <sys/ioctl.h> 107 108 #ifndef _GNU_SOURCE 109 #define _GNU_SOURCE 110 #include <sched.h> 111 #undef _GNU_SOURCE 112 #else 113 #include <sched.h> 114 #endif 115 116 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 117 // getrusage() is prepared to handle the associated failure. 118 #ifndef RUSAGE_THREAD 119 #define RUSAGE_THREAD (1) /* only the calling thread */ 120 #endif 121 122 #define MAX_PATH (2 * K) 123 124 #define MAX_SECS 100000000 125 126 // for timer info max values which include all bits 127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 128 129 #define LARGEPAGES_BIT (1 << 6) 130 //////////////////////////////////////////////////////////////////////////////// 131 // global variables 132 julong os::Linux::_physical_memory = 0; 133 134 address os::Linux::_initial_thread_stack_bottom = NULL; 135 uintptr_t os::Linux::_initial_thread_stack_size = 0; 136 137 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 138 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 139 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 140 Mutex* os::Linux::_createThread_lock = NULL; 141 pthread_t os::Linux::_main_thread; 142 int os::Linux::_page_size = -1; 143 bool os::Linux::_supports_fast_thread_cpu_time = false; 144 uint32_t os::Linux::_os_version = 0; 145 const char * os::Linux::_glibc_version = "unknown"; 146 const char * os::Linux::_libpthread_version = "unknown"; 147 pthread_condattr_t os::Linux::_condattr[1]; 148 149 static jlong initial_time_count=0; 150 151 static int clock_tics_per_sec = 100; 152 153 // For diagnostics to print a message once. see run_periodic_checks 154 static sigset_t check_signal_done; 155 static bool check_signals = true; 156 157 // Signal number used to suspend/resume a thread 158 159 // do not use any signal number less than SIGSEGV, see 4355769 160 static int SR_signum = SIGUSR2; 161 sigset_t SR_sigset; 162 163 // Declarations 164 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 165 166 // utility functions 167 168 static int SR_initialize(); 169 170 julong os::available_memory() { 171 return Linux::available_memory(); 172 } 173 174 julong os::Linux::available_memory() { 175 // values in struct sysinfo are "unsigned long" 176 struct sysinfo si; 177 sysinfo(&si); 178 179 return (julong)si.freeram * si.mem_unit; 180 } 181 182 julong os::physical_memory() { 183 return Linux::physical_memory(); 184 } 185 186 // Return true if user is running as root. 187 188 bool os::have_special_privileges() { 189 static bool init = false; 190 static bool privileges = false; 191 if (!init) { 192 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 193 init = true; 194 } 195 return privileges; 196 } 197 198 199 #ifndef SYS_gettid 200 // i386: 224, ia64: 1105, amd64: 186, sparc 143 201 #ifdef __ia64__ 202 #define SYS_gettid 1105 203 #else 204 #ifdef __i386__ 205 #define SYS_gettid 224 206 #else 207 #ifdef __amd64__ 208 #define SYS_gettid 186 209 #else 210 #ifdef __sparc__ 211 #define SYS_gettid 143 212 #else 213 #error define gettid for the arch 214 #endif 215 #endif 216 #endif 217 #endif 218 #endif 219 220 221 // pid_t gettid() 222 // 223 // Returns the kernel thread id of the currently running thread. Kernel 224 // thread id is used to access /proc. 225 pid_t os::Linux::gettid() { 226 int rslt = syscall(SYS_gettid); 227 assert(rslt != -1, "must be."); // old linuxthreads implementation? 228 return (pid_t)rslt; 229 } 230 231 // Most versions of linux have a bug where the number of processors are 232 // determined by looking at the /proc file system. In a chroot environment, 233 // the system call returns 1. This causes the VM to act as if it is 234 // a single processor and elide locking (see is_MP() call). 235 static bool unsafe_chroot_detected = false; 236 static const char *unstable_chroot_error = "/proc file system not found.\n" 237 "Java may be unstable running multithreaded in a chroot " 238 "environment on Linux when /proc filesystem is not mounted."; 239 240 void os::Linux::initialize_system_info() { 241 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 242 if (processor_count() == 1) { 243 pid_t pid = os::Linux::gettid(); 244 char fname[32]; 245 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 246 FILE *fp = fopen(fname, "r"); 247 if (fp == NULL) { 248 unsafe_chroot_detected = true; 249 } else { 250 fclose(fp); 251 } 252 } 253 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 254 assert(processor_count() > 0, "linux error"); 255 } 256 257 void os::init_system_properties_values() { 258 // The next steps are taken in the product version: 259 // 260 // Obtain the JAVA_HOME value from the location of libjvm.so. 261 // This library should be located at: 262 // <JAVA_HOME>/lib/{client|server}/libjvm.so. 263 // 264 // If "/jre/lib/" appears at the right place in the path, then we 265 // assume libjvm.so is installed in a JDK and we use this path. 266 // 267 // Otherwise exit with message: "Could not create the Java virtual machine." 268 // 269 // The following extra steps are taken in the debugging version: 270 // 271 // If "/jre/lib/" does NOT appear at the right place in the path 272 // instead of exit check for $JAVA_HOME environment variable. 273 // 274 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 275 // then we append a fake suffix "hotspot/libjvm.so" to this path so 276 // it looks like libjvm.so is installed there 277 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 278 // 279 // Otherwise exit. 280 // 281 // Important note: if the location of libjvm.so changes this 282 // code needs to be changed accordingly. 283 284 // See ld(1): 285 // The linker uses the following search paths to locate required 286 // shared libraries: 287 // 1: ... 288 // ... 289 // 7: The default directories, normally /lib and /usr/lib. 290 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390) 291 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 292 #else 293 #define DEFAULT_LIBPATH "/lib:/usr/lib" 294 #endif 295 296 // Base path of extensions installed on the system. 297 #define SYS_EXT_DIR "/usr/java/packages" 298 #define EXTENSIONS_DIR "/lib/ext" 299 300 // Buffer that fits several sprintfs. 301 // Note that the space for the colon and the trailing null are provided 302 // by the nulls included by the sizeof operator. 303 const size_t bufsize = 304 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 305 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 306 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 307 308 // sysclasspath, java_home, dll_dir 309 { 310 char *pslash; 311 os::jvm_path(buf, bufsize); 312 313 // Found the full path to libjvm.so. 314 // Now cut the path to <java_home>/jre if we can. 315 pslash = strrchr(buf, '/'); 316 if (pslash != NULL) { 317 *pslash = '\0'; // Get rid of /libjvm.so. 318 } 319 pslash = strrchr(buf, '/'); 320 if (pslash != NULL) { 321 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 322 } 323 Arguments::set_dll_dir(buf); 324 325 if (pslash != NULL) { 326 pslash = strrchr(buf, '/'); 327 if (pslash != NULL) { 328 *pslash = '\0'; // Get rid of /lib. 329 } 330 } 331 Arguments::set_java_home(buf); 332 set_boot_path('/', ':'); 333 } 334 335 // Where to look for native libraries. 336 // 337 // Note: Due to a legacy implementation, most of the library path 338 // is set in the launcher. This was to accomodate linking restrictions 339 // on legacy Linux implementations (which are no longer supported). 340 // Eventually, all the library path setting will be done here. 341 // 342 // However, to prevent the proliferation of improperly built native 343 // libraries, the new path component /usr/java/packages is added here. 344 // Eventually, all the library path setting will be done here. 345 { 346 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 347 // should always exist (until the legacy problem cited above is 348 // addressed). 349 const char *v = ::getenv("LD_LIBRARY_PATH"); 350 const char *v_colon = ":"; 351 if (v == NULL) { v = ""; v_colon = ""; } 352 // That's +1 for the colon and +1 for the trailing '\0'. 353 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 354 strlen(v) + 1 + 355 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1, 356 mtInternal); 357 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon); 358 Arguments::set_library_path(ld_library_path); 359 FREE_C_HEAP_ARRAY(char, ld_library_path); 360 } 361 362 // Extensions directories. 363 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 364 Arguments::set_ext_dirs(buf); 365 366 FREE_C_HEAP_ARRAY(char, buf); 367 368 #undef DEFAULT_LIBPATH 369 #undef SYS_EXT_DIR 370 #undef EXTENSIONS_DIR 371 } 372 373 //////////////////////////////////////////////////////////////////////////////// 374 // breakpoint support 375 376 void os::breakpoint() { 377 BREAKPOINT; 378 } 379 380 extern "C" void breakpoint() { 381 // use debugger to set breakpoint here 382 } 383 384 //////////////////////////////////////////////////////////////////////////////// 385 // signal support 386 387 debug_only(static bool signal_sets_initialized = false); 388 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 389 390 bool os::Linux::is_sig_ignored(int sig) { 391 struct sigaction oact; 392 sigaction(sig, (struct sigaction*)NULL, &oact); 393 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 394 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 395 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 396 return true; 397 } else { 398 return false; 399 } 400 } 401 402 void os::Linux::signal_sets_init() { 403 // Should also have an assertion stating we are still single-threaded. 404 assert(!signal_sets_initialized, "Already initialized"); 405 // Fill in signals that are necessarily unblocked for all threads in 406 // the VM. Currently, we unblock the following signals: 407 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 408 // by -Xrs (=ReduceSignalUsage)); 409 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 410 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 411 // the dispositions or masks wrt these signals. 412 // Programs embedding the VM that want to use the above signals for their 413 // own purposes must, at this time, use the "-Xrs" option to prevent 414 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 415 // (See bug 4345157, and other related bugs). 416 // In reality, though, unblocking these signals is really a nop, since 417 // these signals are not blocked by default. 418 sigemptyset(&unblocked_sigs); 419 sigemptyset(&allowdebug_blocked_sigs); 420 sigaddset(&unblocked_sigs, SIGILL); 421 sigaddset(&unblocked_sigs, SIGSEGV); 422 sigaddset(&unblocked_sigs, SIGBUS); 423 sigaddset(&unblocked_sigs, SIGFPE); 424 #if defined(PPC64) 425 sigaddset(&unblocked_sigs, SIGTRAP); 426 #endif 427 sigaddset(&unblocked_sigs, SR_signum); 428 429 if (!ReduceSignalUsage) { 430 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 431 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 432 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 433 } 434 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 435 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 436 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 437 } 438 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 439 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 441 } 442 } 443 // Fill in signals that are blocked by all but the VM thread. 444 sigemptyset(&vm_sigs); 445 if (!ReduceSignalUsage) { 446 sigaddset(&vm_sigs, BREAK_SIGNAL); 447 } 448 debug_only(signal_sets_initialized = true); 449 450 } 451 452 // These are signals that are unblocked while a thread is running Java. 453 // (For some reason, they get blocked by default.) 454 sigset_t* os::Linux::unblocked_signals() { 455 assert(signal_sets_initialized, "Not initialized"); 456 return &unblocked_sigs; 457 } 458 459 // These are the signals that are blocked while a (non-VM) thread is 460 // running Java. Only the VM thread handles these signals. 461 sigset_t* os::Linux::vm_signals() { 462 assert(signal_sets_initialized, "Not initialized"); 463 return &vm_sigs; 464 } 465 466 // These are signals that are blocked during cond_wait to allow debugger in 467 sigset_t* os::Linux::allowdebug_blocked_signals() { 468 assert(signal_sets_initialized, "Not initialized"); 469 return &allowdebug_blocked_sigs; 470 } 471 472 void os::Linux::hotspot_sigmask(Thread* thread) { 473 474 //Save caller's signal mask before setting VM signal mask 475 sigset_t caller_sigmask; 476 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 477 478 OSThread* osthread = thread->osthread(); 479 osthread->set_caller_sigmask(caller_sigmask); 480 481 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 482 483 if (!ReduceSignalUsage) { 484 if (thread->is_VM_thread()) { 485 // Only the VM thread handles BREAK_SIGNAL ... 486 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 487 } else { 488 // ... all other threads block BREAK_SIGNAL 489 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 490 } 491 } 492 } 493 494 ////////////////////////////////////////////////////////////////////////////// 495 // detecting pthread library 496 497 void os::Linux::libpthread_init() { 498 // Save glibc and pthread version strings. 499 #if !defined(_CS_GNU_LIBC_VERSION) || \ 500 !defined(_CS_GNU_LIBPTHREAD_VERSION) 501 #error "glibc too old (< 2.3.2)" 502 #endif 503 504 size_t n; 505 506 n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 507 if (n > 0) { 508 char* str = (char *)malloc(n, mtInternal); 509 confstr(_CS_GNU_LIBC_VERSION, str, n); 510 os::Linux::set_glibc_version(str); 511 } 512 513 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 514 if (n > 0) { 515 char* str = (char *)malloc(n, mtInternal); 516 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 517 os::Linux::set_libpthread_version(str); 518 } 519 } 520 521 ///////////////////////////////////////////////////////////////////////////// 522 // thread stack expansion 523 524 // os::Linux::manually_expand_stack() takes care of expanding the thread 525 // stack. Note that this is normally not needed: pthread stacks allocate 526 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 527 // committed. Therefore it is not necessary to expand the stack manually. 528 // 529 // Manually expanding the stack was historically needed on LinuxThreads 530 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 531 // it is kept to deal with very rare corner cases: 532 // 533 // For one, user may run the VM on an own implementation of threads 534 // whose stacks are - like the old LinuxThreads - implemented using 535 // mmap(MAP_GROWSDOWN). 536 // 537 // Also, this coding may be needed if the VM is running on the primordial 538 // thread. Normally we avoid running on the primordial thread; however, 539 // user may still invoke the VM on the primordial thread. 540 // 541 // The following historical comment describes the details about running 542 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 543 544 545 // Force Linux kernel to expand current thread stack. If "bottom" is close 546 // to the stack guard, caller should block all signals. 547 // 548 // MAP_GROWSDOWN: 549 // A special mmap() flag that is used to implement thread stacks. It tells 550 // kernel that the memory region should extend downwards when needed. This 551 // allows early versions of LinuxThreads to only mmap the first few pages 552 // when creating a new thread. Linux kernel will automatically expand thread 553 // stack as needed (on page faults). 554 // 555 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 556 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 557 // region, it's hard to tell if the fault is due to a legitimate stack 558 // access or because of reading/writing non-exist memory (e.g. buffer 559 // overrun). As a rule, if the fault happens below current stack pointer, 560 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 561 // application (see Linux kernel fault.c). 562 // 563 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 564 // stack overflow detection. 565 // 566 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 567 // not use MAP_GROWSDOWN. 568 // 569 // To get around the problem and allow stack banging on Linux, we need to 570 // manually expand thread stack after receiving the SIGSEGV. 571 // 572 // There are two ways to expand thread stack to address "bottom", we used 573 // both of them in JVM before 1.5: 574 // 1. adjust stack pointer first so that it is below "bottom", and then 575 // touch "bottom" 576 // 2. mmap() the page in question 577 // 578 // Now alternate signal stack is gone, it's harder to use 2. For instance, 579 // if current sp is already near the lower end of page 101, and we need to 580 // call mmap() to map page 100, it is possible that part of the mmap() frame 581 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 582 // That will destroy the mmap() frame and cause VM to crash. 583 // 584 // The following code works by adjusting sp first, then accessing the "bottom" 585 // page to force a page fault. Linux kernel will then automatically expand the 586 // stack mapping. 587 // 588 // _expand_stack_to() assumes its frame size is less than page size, which 589 // should always be true if the function is not inlined. 590 591 static void NOINLINE _expand_stack_to(address bottom) { 592 address sp; 593 size_t size; 594 volatile char *p; 595 596 // Adjust bottom to point to the largest address within the same page, it 597 // gives us a one-page buffer if alloca() allocates slightly more memory. 598 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 599 bottom += os::Linux::page_size() - 1; 600 601 // sp might be slightly above current stack pointer; if that's the case, we 602 // will alloca() a little more space than necessary, which is OK. Don't use 603 // os::current_stack_pointer(), as its result can be slightly below current 604 // stack pointer, causing us to not alloca enough to reach "bottom". 605 sp = (address)&sp; 606 607 if (sp > bottom) { 608 size = sp - bottom; 609 p = (volatile char *)alloca(size); 610 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 611 p[0] = '\0'; 612 } 613 } 614 615 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 616 assert(t!=NULL, "just checking"); 617 assert(t->osthread()->expanding_stack(), "expand should be set"); 618 assert(t->stack_base() != NULL, "stack_base was not initialized"); 619 620 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) { 621 sigset_t mask_all, old_sigset; 622 sigfillset(&mask_all); 623 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 624 _expand_stack_to(addr); 625 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 626 return true; 627 } 628 return false; 629 } 630 631 ////////////////////////////////////////////////////////////////////////////// 632 // create new thread 633 634 // Thread start routine for all newly created threads 635 static void *thread_native_entry(Thread *thread) { 636 // Try to randomize the cache line index of hot stack frames. 637 // This helps when threads of the same stack traces evict each other's 638 // cache lines. The threads can be either from the same JVM instance, or 639 // from different JVM instances. The benefit is especially true for 640 // processors with hyperthreading technology. 641 static int counter = 0; 642 int pid = os::current_process_id(); 643 alloca(((pid ^ counter++) & 7) * 128); 644 645 thread->initialize_thread_current(); 646 647 OSThread* osthread = thread->osthread(); 648 Monitor* sync = osthread->startThread_lock(); 649 650 osthread->set_thread_id(os::current_thread_id()); 651 652 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 653 os::current_thread_id(), (uintx) pthread_self()); 654 655 if (UseNUMA) { 656 int lgrp_id = os::numa_get_group_id(); 657 if (lgrp_id != -1) { 658 thread->set_lgrp_id(lgrp_id); 659 } 660 } 661 // initialize signal mask for this thread 662 os::Linux::hotspot_sigmask(thread); 663 664 // initialize floating point control register 665 os::Linux::init_thread_fpu_state(); 666 667 // handshaking with parent thread 668 { 669 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 670 671 // notify parent thread 672 osthread->set_state(INITIALIZED); 673 sync->notify_all(); 674 675 // wait until os::start_thread() 676 while (osthread->get_state() == INITIALIZED) { 677 sync->wait(Mutex::_no_safepoint_check_flag); 678 } 679 } 680 681 // call one more level start routine 682 thread->run(); 683 684 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 685 os::current_thread_id(), (uintx) pthread_self()); 686 687 // If a thread has not deleted itself ("delete this") as part of its 688 // termination sequence, we have to ensure thread-local-storage is 689 // cleared before we actually terminate. No threads should ever be 690 // deleted asynchronously with respect to their termination. 691 if (Thread::current_or_null_safe() != NULL) { 692 assert(Thread::current_or_null_safe() == thread, "current thread is wrong"); 693 thread->clear_thread_current(); 694 } 695 696 return 0; 697 } 698 699 bool os::create_thread(Thread* thread, ThreadType thr_type, 700 size_t req_stack_size) { 701 assert(thread->osthread() == NULL, "caller responsible"); 702 703 // Allocate the OSThread object 704 OSThread* osthread = new OSThread(NULL, NULL); 705 if (osthread == NULL) { 706 return false; 707 } 708 709 // set the correct thread state 710 osthread->set_thread_type(thr_type); 711 712 // Initial state is ALLOCATED but not INITIALIZED 713 osthread->set_state(ALLOCATED); 714 715 thread->set_osthread(osthread); 716 717 // init thread attributes 718 pthread_attr_t attr; 719 pthread_attr_init(&attr); 720 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 721 722 // Calculate stack size if it's not specified by caller. 723 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size); 724 // In the Linux NPTL pthread implementation the guard size mechanism 725 // is not implemented properly. The posix standard requires adding 726 // the size of the guard pages to the stack size, instead Linux 727 // takes the space out of 'stacksize'. Thus we adapt the requested 728 // stack_size by the size of the guard pages to mimick proper 729 // behaviour. 730 stack_size = align_size_up(stack_size + os::Linux::default_guard_size(thr_type), vm_page_size()); 731 pthread_attr_setstacksize(&attr, stack_size); 732 733 // Configure glibc guard page. 734 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 735 736 ThreadState state; 737 738 { 739 pthread_t tid; 740 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread); 741 742 char buf[64]; 743 if (ret == 0) { 744 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ", 745 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 746 } else { 747 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.", 748 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr)); 749 } 750 751 pthread_attr_destroy(&attr); 752 753 if (ret != 0) { 754 // Need to clean up stuff we've allocated so far 755 thread->set_osthread(NULL); 756 delete osthread; 757 return false; 758 } 759 760 // Store pthread info into the OSThread 761 osthread->set_pthread_id(tid); 762 763 // Wait until child thread is either initialized or aborted 764 { 765 Monitor* sync_with_child = osthread->startThread_lock(); 766 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 767 while ((state = osthread->get_state()) == ALLOCATED) { 768 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 769 } 770 } 771 } 772 773 // Aborted due to thread limit being reached 774 if (state == ZOMBIE) { 775 thread->set_osthread(NULL); 776 delete osthread; 777 return false; 778 } 779 780 // The thread is returned suspended (in state INITIALIZED), 781 // and is started higher up in the call chain 782 assert(state == INITIALIZED, "race condition"); 783 return true; 784 } 785 786 ///////////////////////////////////////////////////////////////////////////// 787 // attach existing thread 788 789 // bootstrap the main thread 790 bool os::create_main_thread(JavaThread* thread) { 791 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 792 return create_attached_thread(thread); 793 } 794 795 bool os::create_attached_thread(JavaThread* thread) { 796 #ifdef ASSERT 797 thread->verify_not_published(); 798 #endif 799 800 // Allocate the OSThread object 801 OSThread* osthread = new OSThread(NULL, NULL); 802 803 if (osthread == NULL) { 804 return false; 805 } 806 807 // Store pthread info into the OSThread 808 osthread->set_thread_id(os::Linux::gettid()); 809 osthread->set_pthread_id(::pthread_self()); 810 811 // initialize floating point control register 812 os::Linux::init_thread_fpu_state(); 813 814 // Initial thread state is RUNNABLE 815 osthread->set_state(RUNNABLE); 816 817 thread->set_osthread(osthread); 818 819 if (UseNUMA) { 820 int lgrp_id = os::numa_get_group_id(); 821 if (lgrp_id != -1) { 822 thread->set_lgrp_id(lgrp_id); 823 } 824 } 825 826 if (os::Linux::is_initial_thread()) { 827 // If current thread is initial thread, its stack is mapped on demand, 828 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 829 // the entire stack region to avoid SEGV in stack banging. 830 // It is also useful to get around the heap-stack-gap problem on SuSE 831 // kernel (see 4821821 for details). We first expand stack to the top 832 // of yellow zone, then enable stack yellow zone (order is significant, 833 // enabling yellow zone first will crash JVM on SuSE Linux), so there 834 // is no gap between the last two virtual memory regions. 835 836 JavaThread *jt = (JavaThread *)thread; 837 address addr = jt->stack_reserved_zone_base(); 838 assert(addr != NULL, "initialization problem?"); 839 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 840 841 osthread->set_expanding_stack(); 842 os::Linux::manually_expand_stack(jt, addr); 843 osthread->clear_expanding_stack(); 844 } 845 846 // initialize signal mask for this thread 847 // and save the caller's signal mask 848 os::Linux::hotspot_sigmask(thread); 849 850 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").", 851 os::current_thread_id(), (uintx) pthread_self()); 852 853 return true; 854 } 855 856 void os::pd_start_thread(Thread* thread) { 857 OSThread * osthread = thread->osthread(); 858 assert(osthread->get_state() != INITIALIZED, "just checking"); 859 Monitor* sync_with_child = osthread->startThread_lock(); 860 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 861 sync_with_child->notify(); 862 } 863 864 // Free Linux resources related to the OSThread 865 void os::free_thread(OSThread* osthread) { 866 assert(osthread != NULL, "osthread not set"); 867 868 // We are told to free resources of the argument thread, 869 // but we can only really operate on the current thread. 870 assert(Thread::current()->osthread() == osthread, 871 "os::free_thread but not current thread"); 872 873 #ifdef ASSERT 874 sigset_t current; 875 sigemptyset(¤t); 876 pthread_sigmask(SIG_SETMASK, NULL, ¤t); 877 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!"); 878 #endif 879 880 // Restore caller's signal mask 881 sigset_t sigmask = osthread->caller_sigmask(); 882 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 883 884 delete osthread; 885 } 886 887 ////////////////////////////////////////////////////////////////////////////// 888 // initial thread 889 890 // Check if current thread is the initial thread, similar to Solaris thr_main. 891 bool os::Linux::is_initial_thread(void) { 892 char dummy; 893 // If called before init complete, thread stack bottom will be null. 894 // Can be called if fatal error occurs before initialization. 895 if (initial_thread_stack_bottom() == NULL) return false; 896 assert(initial_thread_stack_bottom() != NULL && 897 initial_thread_stack_size() != 0, 898 "os::init did not locate initial thread's stack region"); 899 if ((address)&dummy >= initial_thread_stack_bottom() && 900 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 901 return true; 902 } else { 903 return false; 904 } 905 } 906 907 // Find the virtual memory area that contains addr 908 static bool find_vma(address addr, address* vma_low, address* vma_high) { 909 FILE *fp = fopen("/proc/self/maps", "r"); 910 if (fp) { 911 address low, high; 912 while (!feof(fp)) { 913 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 914 if (low <= addr && addr < high) { 915 if (vma_low) *vma_low = low; 916 if (vma_high) *vma_high = high; 917 fclose(fp); 918 return true; 919 } 920 } 921 for (;;) { 922 int ch = fgetc(fp); 923 if (ch == EOF || ch == (int)'\n') break; 924 } 925 } 926 fclose(fp); 927 } 928 return false; 929 } 930 931 // Locate initial thread stack. This special handling of initial thread stack 932 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 933 // bogus value for the primordial process thread. While the launcher has created 934 // the VM in a new thread since JDK 6, we still have to allow for the use of the 935 // JNI invocation API from a primordial thread. 936 void os::Linux::capture_initial_stack(size_t max_size) { 937 938 // max_size is either 0 (which means accept OS default for thread stacks) or 939 // a user-specified value known to be at least the minimum needed. If we 940 // are actually on the primordial thread we can make it appear that we have a 941 // smaller max_size stack by inserting the guard pages at that location. But we 942 // cannot do anything to emulate a larger stack than what has been provided by 943 // the OS or threading library. In fact if we try to use a stack greater than 944 // what is set by rlimit then we will crash the hosting process. 945 946 // Maximum stack size is the easy part, get it from RLIMIT_STACK. 947 // If this is "unlimited" then it will be a huge value. 948 struct rlimit rlim; 949 getrlimit(RLIMIT_STACK, &rlim); 950 size_t stack_size = rlim.rlim_cur; 951 952 // 6308388: a bug in ld.so will relocate its own .data section to the 953 // lower end of primordial stack; reduce ulimit -s value a little bit 954 // so we won't install guard page on ld.so's data section. 955 stack_size -= 2 * page_size(); 956 957 // Try to figure out where the stack base (top) is. This is harder. 958 // 959 // When an application is started, glibc saves the initial stack pointer in 960 // a global variable "__libc_stack_end", which is then used by system 961 // libraries. __libc_stack_end should be pretty close to stack top. The 962 // variable is available since the very early days. However, because it is 963 // a private interface, it could disappear in the future. 964 // 965 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 966 // to __libc_stack_end, it is very close to stack top, but isn't the real 967 // stack top. Note that /proc may not exist if VM is running as a chroot 968 // program, so reading /proc/<pid>/stat could fail. Also the contents of 969 // /proc/<pid>/stat could change in the future (though unlikely). 970 // 971 // We try __libc_stack_end first. If that doesn't work, look for 972 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 973 // as a hint, which should work well in most cases. 974 975 uintptr_t stack_start; 976 977 // try __libc_stack_end first 978 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 979 if (p && *p) { 980 stack_start = *p; 981 } else { 982 // see if we can get the start_stack field from /proc/self/stat 983 FILE *fp; 984 int pid; 985 char state; 986 int ppid; 987 int pgrp; 988 int session; 989 int nr; 990 int tpgrp; 991 unsigned long flags; 992 unsigned long minflt; 993 unsigned long cminflt; 994 unsigned long majflt; 995 unsigned long cmajflt; 996 unsigned long utime; 997 unsigned long stime; 998 long cutime; 999 long cstime; 1000 long prio; 1001 long nice; 1002 long junk; 1003 long it_real; 1004 uintptr_t start; 1005 uintptr_t vsize; 1006 intptr_t rss; 1007 uintptr_t rsslim; 1008 uintptr_t scodes; 1009 uintptr_t ecode; 1010 int i; 1011 1012 // Figure what the primordial thread stack base is. Code is inspired 1013 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1014 // followed by command name surrounded by parentheses, state, etc. 1015 char stat[2048]; 1016 int statlen; 1017 1018 fp = fopen("/proc/self/stat", "r"); 1019 if (fp) { 1020 statlen = fread(stat, 1, 2047, fp); 1021 stat[statlen] = '\0'; 1022 fclose(fp); 1023 1024 // Skip pid and the command string. Note that we could be dealing with 1025 // weird command names, e.g. user could decide to rename java launcher 1026 // to "java 1.4.2 :)", then the stat file would look like 1027 // 1234 (java 1.4.2 :)) R ... ... 1028 // We don't really need to know the command string, just find the last 1029 // occurrence of ")" and then start parsing from there. See bug 4726580. 1030 char * s = strrchr(stat, ')'); 1031 1032 i = 0; 1033 if (s) { 1034 // Skip blank chars 1035 do { s++; } while (s && isspace(*s)); 1036 1037 #define _UFM UINTX_FORMAT 1038 #define _DFM INTX_FORMAT 1039 1040 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1041 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 1042 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM, 1043 &state, // 3 %c 1044 &ppid, // 4 %d 1045 &pgrp, // 5 %d 1046 &session, // 6 %d 1047 &nr, // 7 %d 1048 &tpgrp, // 8 %d 1049 &flags, // 9 %lu 1050 &minflt, // 10 %lu 1051 &cminflt, // 11 %lu 1052 &majflt, // 12 %lu 1053 &cmajflt, // 13 %lu 1054 &utime, // 14 %lu 1055 &stime, // 15 %lu 1056 &cutime, // 16 %ld 1057 &cstime, // 17 %ld 1058 &prio, // 18 %ld 1059 &nice, // 19 %ld 1060 &junk, // 20 %ld 1061 &it_real, // 21 %ld 1062 &start, // 22 UINTX_FORMAT 1063 &vsize, // 23 UINTX_FORMAT 1064 &rss, // 24 INTX_FORMAT 1065 &rsslim, // 25 UINTX_FORMAT 1066 &scodes, // 26 UINTX_FORMAT 1067 &ecode, // 27 UINTX_FORMAT 1068 &stack_start); // 28 UINTX_FORMAT 1069 } 1070 1071 #undef _UFM 1072 #undef _DFM 1073 1074 if (i != 28 - 2) { 1075 assert(false, "Bad conversion from /proc/self/stat"); 1076 // product mode - assume we are the initial thread, good luck in the 1077 // embedded case. 1078 warning("Can't detect initial thread stack location - bad conversion"); 1079 stack_start = (uintptr_t) &rlim; 1080 } 1081 } else { 1082 // For some reason we can't open /proc/self/stat (for example, running on 1083 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1084 // most cases, so don't abort: 1085 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1086 stack_start = (uintptr_t) &rlim; 1087 } 1088 } 1089 1090 // Now we have a pointer (stack_start) very close to the stack top, the 1091 // next thing to do is to figure out the exact location of stack top. We 1092 // can find out the virtual memory area that contains stack_start by 1093 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1094 // and its upper limit is the real stack top. (again, this would fail if 1095 // running inside chroot, because /proc may not exist.) 1096 1097 uintptr_t stack_top; 1098 address low, high; 1099 if (find_vma((address)stack_start, &low, &high)) { 1100 // success, "high" is the true stack top. (ignore "low", because initial 1101 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1102 stack_top = (uintptr_t)high; 1103 } else { 1104 // failed, likely because /proc/self/maps does not exist 1105 warning("Can't detect initial thread stack location - find_vma failed"); 1106 // best effort: stack_start is normally within a few pages below the real 1107 // stack top, use it as stack top, and reduce stack size so we won't put 1108 // guard page outside stack. 1109 stack_top = stack_start; 1110 stack_size -= 16 * page_size(); 1111 } 1112 1113 // stack_top could be partially down the page so align it 1114 stack_top = align_size_up(stack_top, page_size()); 1115 1116 // Allowed stack value is minimum of max_size and what we derived from rlimit 1117 if (max_size > 0) { 1118 _initial_thread_stack_size = MIN2(max_size, stack_size); 1119 } else { 1120 // Accept the rlimit max, but if stack is unlimited then it will be huge, so 1121 // clamp it at 8MB as we do on Solaris 1122 _initial_thread_stack_size = MIN2(stack_size, 8*M); 1123 } 1124 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1125 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1126 1127 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!"); 1128 1129 if (log_is_enabled(Info, os, thread)) { 1130 // See if we seem to be on primordial process thread 1131 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) && 1132 uintptr_t(&rlim) < stack_top; 1133 1134 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: " 1135 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT, 1136 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K, 1137 stack_top, intptr_t(_initial_thread_stack_bottom)); 1138 } 1139 } 1140 1141 //////////////////////////////////////////////////////////////////////////////// 1142 // time support 1143 1144 // Time since start-up in seconds to a fine granularity. 1145 // Used by VMSelfDestructTimer and the MemProfiler. 1146 double os::elapsedTime() { 1147 1148 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1149 } 1150 1151 jlong os::elapsed_counter() { 1152 return javaTimeNanos() - initial_time_count; 1153 } 1154 1155 jlong os::elapsed_frequency() { 1156 return NANOSECS_PER_SEC; // nanosecond resolution 1157 } 1158 1159 bool os::supports_vtime() { return true; } 1160 bool os::enable_vtime() { return false; } 1161 bool os::vtime_enabled() { return false; } 1162 1163 double os::elapsedVTime() { 1164 struct rusage usage; 1165 int retval = getrusage(RUSAGE_THREAD, &usage); 1166 if (retval == 0) { 1167 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000); 1168 } else { 1169 // better than nothing, but not much 1170 return elapsedTime(); 1171 } 1172 } 1173 1174 jlong os::javaTimeMillis() { 1175 timeval time; 1176 int status = gettimeofday(&time, NULL); 1177 assert(status != -1, "linux error"); 1178 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1179 } 1180 1181 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1182 timeval time; 1183 int status = gettimeofday(&time, NULL); 1184 assert(status != -1, "linux error"); 1185 seconds = jlong(time.tv_sec); 1186 nanos = jlong(time.tv_usec) * 1000; 1187 } 1188 1189 1190 #ifndef CLOCK_MONOTONIC 1191 #define CLOCK_MONOTONIC (1) 1192 #endif 1193 1194 void os::Linux::clock_init() { 1195 // we do dlopen's in this particular order due to bug in linux 1196 // dynamical loader (see 6348968) leading to crash on exit 1197 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1198 if (handle == NULL) { 1199 handle = dlopen("librt.so", RTLD_LAZY); 1200 } 1201 1202 if (handle) { 1203 int (*clock_getres_func)(clockid_t, struct timespec*) = 1204 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1205 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1206 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1207 if (clock_getres_func && clock_gettime_func) { 1208 // See if monotonic clock is supported by the kernel. Note that some 1209 // early implementations simply return kernel jiffies (updated every 1210 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1211 // for nano time (though the monotonic property is still nice to have). 1212 // It's fixed in newer kernels, however clock_getres() still returns 1213 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1214 // resolution for now. Hopefully as people move to new kernels, this 1215 // won't be a problem. 1216 struct timespec res; 1217 struct timespec tp; 1218 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1219 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1220 // yes, monotonic clock is supported 1221 _clock_gettime = clock_gettime_func; 1222 return; 1223 } else { 1224 // close librt if there is no monotonic clock 1225 dlclose(handle); 1226 } 1227 } 1228 } 1229 warning("No monotonic clock was available - timed services may " \ 1230 "be adversely affected if the time-of-day clock changes"); 1231 } 1232 1233 #ifndef SYS_clock_getres 1234 #if defined(X86) || defined(PPC64) || defined(S390) 1235 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261) 1236 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1237 #else 1238 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1239 #define sys_clock_getres(x,y) -1 1240 #endif 1241 #else 1242 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1243 #endif 1244 1245 void os::Linux::fast_thread_clock_init() { 1246 if (!UseLinuxPosixThreadCPUClocks) { 1247 return; 1248 } 1249 clockid_t clockid; 1250 struct timespec tp; 1251 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1252 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1253 1254 // Switch to using fast clocks for thread cpu time if 1255 // the sys_clock_getres() returns 0 error code. 1256 // Note, that some kernels may support the current thread 1257 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1258 // returned by the pthread_getcpuclockid(). 1259 // If the fast Posix clocks are supported then the sys_clock_getres() 1260 // must return at least tp.tv_sec == 0 which means a resolution 1261 // better than 1 sec. This is extra check for reliability. 1262 1263 if (pthread_getcpuclockid_func && 1264 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1265 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1266 _supports_fast_thread_cpu_time = true; 1267 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1268 } 1269 } 1270 1271 jlong os::javaTimeNanos() { 1272 if (os::supports_monotonic_clock()) { 1273 struct timespec tp; 1274 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1275 assert(status == 0, "gettime error"); 1276 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1277 return result; 1278 } else { 1279 timeval time; 1280 int status = gettimeofday(&time, NULL); 1281 assert(status != -1, "linux error"); 1282 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1283 return 1000 * usecs; 1284 } 1285 } 1286 1287 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1288 if (os::supports_monotonic_clock()) { 1289 info_ptr->max_value = ALL_64_BITS; 1290 1291 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1292 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1293 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1294 } else { 1295 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1296 info_ptr->max_value = ALL_64_BITS; 1297 1298 // gettimeofday is a real time clock so it skips 1299 info_ptr->may_skip_backward = true; 1300 info_ptr->may_skip_forward = true; 1301 } 1302 1303 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1304 } 1305 1306 // Return the real, user, and system times in seconds from an 1307 // arbitrary fixed point in the past. 1308 bool os::getTimesSecs(double* process_real_time, 1309 double* process_user_time, 1310 double* process_system_time) { 1311 struct tms ticks; 1312 clock_t real_ticks = times(&ticks); 1313 1314 if (real_ticks == (clock_t) (-1)) { 1315 return false; 1316 } else { 1317 double ticks_per_second = (double) clock_tics_per_sec; 1318 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1319 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1320 *process_real_time = ((double) real_ticks) / ticks_per_second; 1321 1322 return true; 1323 } 1324 } 1325 1326 1327 char * os::local_time_string(char *buf, size_t buflen) { 1328 struct tm t; 1329 time_t long_time; 1330 time(&long_time); 1331 localtime_r(&long_time, &t); 1332 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1333 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1334 t.tm_hour, t.tm_min, t.tm_sec); 1335 return buf; 1336 } 1337 1338 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1339 return localtime_r(clock, res); 1340 } 1341 1342 //////////////////////////////////////////////////////////////////////////////// 1343 // runtime exit support 1344 1345 // Note: os::shutdown() might be called very early during initialization, or 1346 // called from signal handler. Before adding something to os::shutdown(), make 1347 // sure it is async-safe and can handle partially initialized VM. 1348 void os::shutdown() { 1349 1350 // allow PerfMemory to attempt cleanup of any persistent resources 1351 perfMemory_exit(); 1352 1353 // needs to remove object in file system 1354 AttachListener::abort(); 1355 1356 // flush buffered output, finish log files 1357 ostream_abort(); 1358 1359 // Check for abort hook 1360 abort_hook_t abort_hook = Arguments::abort_hook(); 1361 if (abort_hook != NULL) { 1362 abort_hook(); 1363 } 1364 1365 } 1366 1367 // Note: os::abort() might be called very early during initialization, or 1368 // called from signal handler. Before adding something to os::abort(), make 1369 // sure it is async-safe and can handle partially initialized VM. 1370 void os::abort(bool dump_core, void* siginfo, const void* context) { 1371 os::shutdown(); 1372 if (dump_core) { 1373 #ifndef PRODUCT 1374 fdStream out(defaultStream::output_fd()); 1375 out.print_raw("Current thread is "); 1376 char buf[16]; 1377 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1378 out.print_raw_cr(buf); 1379 out.print_raw_cr("Dumping core ..."); 1380 #endif 1381 ::abort(); // dump core 1382 } 1383 1384 ::exit(1); 1385 } 1386 1387 // Die immediately, no exit hook, no abort hook, no cleanup. 1388 void os::die() { 1389 ::abort(); 1390 } 1391 1392 1393 // This method is a copy of JDK's sysGetLastErrorString 1394 // from src/solaris/hpi/src/system_md.c 1395 1396 size_t os::lasterror(char *buf, size_t len) { 1397 if (errno == 0) return 0; 1398 1399 const char *s = os::strerror(errno); 1400 size_t n = ::strlen(s); 1401 if (n >= len) { 1402 n = len - 1; 1403 } 1404 ::strncpy(buf, s, n); 1405 buf[n] = '\0'; 1406 return n; 1407 } 1408 1409 // thread_id is kernel thread id (similar to Solaris LWP id) 1410 intx os::current_thread_id() { return os::Linux::gettid(); } 1411 int os::current_process_id() { 1412 return ::getpid(); 1413 } 1414 1415 // DLL functions 1416 1417 const char* os::dll_file_extension() { return ".so"; } 1418 1419 // This must be hard coded because it's the system's temporary 1420 // directory not the java application's temp directory, ala java.io.tmpdir. 1421 const char* os::get_temp_directory() { return "/tmp"; } 1422 1423 static bool file_exists(const char* filename) { 1424 struct stat statbuf; 1425 if (filename == NULL || strlen(filename) == 0) { 1426 return false; 1427 } 1428 return os::stat(filename, &statbuf) == 0; 1429 } 1430 1431 bool os::dll_build_name(char* buffer, size_t buflen, 1432 const char* pname, const char* fname) { 1433 bool retval = false; 1434 // Copied from libhpi 1435 const size_t pnamelen = pname ? strlen(pname) : 0; 1436 1437 // Return error on buffer overflow. 1438 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1439 return retval; 1440 } 1441 1442 if (pnamelen == 0) { 1443 snprintf(buffer, buflen, "lib%s.so", fname); 1444 retval = true; 1445 } else if (strchr(pname, *os::path_separator()) != NULL) { 1446 int n; 1447 char** pelements = split_path(pname, &n); 1448 if (pelements == NULL) { 1449 return false; 1450 } 1451 for (int i = 0; i < n; i++) { 1452 // Really shouldn't be NULL, but check can't hurt 1453 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1454 continue; // skip the empty path values 1455 } 1456 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1457 if (file_exists(buffer)) { 1458 retval = true; 1459 break; 1460 } 1461 } 1462 // release the storage 1463 for (int i = 0; i < n; i++) { 1464 if (pelements[i] != NULL) { 1465 FREE_C_HEAP_ARRAY(char, pelements[i]); 1466 } 1467 } 1468 if (pelements != NULL) { 1469 FREE_C_HEAP_ARRAY(char*, pelements); 1470 } 1471 } else { 1472 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1473 retval = true; 1474 } 1475 return retval; 1476 } 1477 1478 // check if addr is inside libjvm.so 1479 bool os::address_is_in_vm(address addr) { 1480 static address libjvm_base_addr; 1481 Dl_info dlinfo; 1482 1483 if (libjvm_base_addr == NULL) { 1484 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1485 libjvm_base_addr = (address)dlinfo.dli_fbase; 1486 } 1487 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1488 } 1489 1490 if (dladdr((void *)addr, &dlinfo) != 0) { 1491 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1492 } 1493 1494 return false; 1495 } 1496 1497 bool os::dll_address_to_function_name(address addr, char *buf, 1498 int buflen, int *offset, 1499 bool demangle) { 1500 // buf is not optional, but offset is optional 1501 assert(buf != NULL, "sanity check"); 1502 1503 Dl_info dlinfo; 1504 1505 if (dladdr((void*)addr, &dlinfo) != 0) { 1506 // see if we have a matching symbol 1507 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1508 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1509 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1510 } 1511 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1512 return true; 1513 } 1514 // no matching symbol so try for just file info 1515 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1516 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1517 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1518 return true; 1519 } 1520 } 1521 } 1522 1523 buf[0] = '\0'; 1524 if (offset != NULL) *offset = -1; 1525 return false; 1526 } 1527 1528 struct _address_to_library_name { 1529 address addr; // input : memory address 1530 size_t buflen; // size of fname 1531 char* fname; // output: library name 1532 address base; // library base addr 1533 }; 1534 1535 static int address_to_library_name_callback(struct dl_phdr_info *info, 1536 size_t size, void *data) { 1537 int i; 1538 bool found = false; 1539 address libbase = NULL; 1540 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1541 1542 // iterate through all loadable segments 1543 for (i = 0; i < info->dlpi_phnum; i++) { 1544 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1545 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1546 // base address of a library is the lowest address of its loaded 1547 // segments. 1548 if (libbase == NULL || libbase > segbase) { 1549 libbase = segbase; 1550 } 1551 // see if 'addr' is within current segment 1552 if (segbase <= d->addr && 1553 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1554 found = true; 1555 } 1556 } 1557 } 1558 1559 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1560 // so dll_address_to_library_name() can fall through to use dladdr() which 1561 // can figure out executable name from argv[0]. 1562 if (found && info->dlpi_name && info->dlpi_name[0]) { 1563 d->base = libbase; 1564 if (d->fname) { 1565 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1566 } 1567 return 1; 1568 } 1569 return 0; 1570 } 1571 1572 bool os::dll_address_to_library_name(address addr, char* buf, 1573 int buflen, int* offset) { 1574 // buf is not optional, but offset is optional 1575 assert(buf != NULL, "sanity check"); 1576 1577 Dl_info dlinfo; 1578 struct _address_to_library_name data; 1579 1580 // There is a bug in old glibc dladdr() implementation that it could resolve 1581 // to wrong library name if the .so file has a base address != NULL. Here 1582 // we iterate through the program headers of all loaded libraries to find 1583 // out which library 'addr' really belongs to. This workaround can be 1584 // removed once the minimum requirement for glibc is moved to 2.3.x. 1585 data.addr = addr; 1586 data.fname = buf; 1587 data.buflen = buflen; 1588 data.base = NULL; 1589 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1590 1591 if (rslt) { 1592 // buf already contains library name 1593 if (offset) *offset = addr - data.base; 1594 return true; 1595 } 1596 if (dladdr((void*)addr, &dlinfo) != 0) { 1597 if (dlinfo.dli_fname != NULL) { 1598 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1599 } 1600 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1601 *offset = addr - (address)dlinfo.dli_fbase; 1602 } 1603 return true; 1604 } 1605 1606 buf[0] = '\0'; 1607 if (offset) *offset = -1; 1608 return false; 1609 } 1610 1611 // Loads .dll/.so and 1612 // in case of error it checks if .dll/.so was built for the 1613 // same architecture as Hotspot is running on 1614 1615 1616 // Remember the stack's state. The Linux dynamic linker will change 1617 // the stack to 'executable' at most once, so we must safepoint only once. 1618 bool os::Linux::_stack_is_executable = false; 1619 1620 // VM operation that loads a library. This is necessary if stack protection 1621 // of the Java stacks can be lost during loading the library. If we 1622 // do not stop the Java threads, they can stack overflow before the stacks 1623 // are protected again. 1624 class VM_LinuxDllLoad: public VM_Operation { 1625 private: 1626 const char *_filename; 1627 char *_ebuf; 1628 int _ebuflen; 1629 void *_lib; 1630 public: 1631 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1632 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1633 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1634 void doit() { 1635 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1636 os::Linux::_stack_is_executable = true; 1637 } 1638 void* loaded_library() { return _lib; } 1639 }; 1640 1641 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1642 void * result = NULL; 1643 bool load_attempted = false; 1644 1645 // Check whether the library to load might change execution rights 1646 // of the stack. If they are changed, the protection of the stack 1647 // guard pages will be lost. We need a safepoint to fix this. 1648 // 1649 // See Linux man page execstack(8) for more info. 1650 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1651 ElfFile ef(filename); 1652 if (!ef.specifies_noexecstack()) { 1653 if (!is_init_completed()) { 1654 os::Linux::_stack_is_executable = true; 1655 // This is OK - No Java threads have been created yet, and hence no 1656 // stack guard pages to fix. 1657 // 1658 // This should happen only when you are building JDK7 using a very 1659 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1660 // 1661 // Dynamic loader will make all stacks executable after 1662 // this function returns, and will not do that again. 1663 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1664 } else { 1665 warning("You have loaded library %s which might have disabled stack guard. " 1666 "The VM will try to fix the stack guard now.\n" 1667 "It's highly recommended that you fix the library with " 1668 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1669 filename); 1670 1671 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1672 JavaThread *jt = JavaThread::current(); 1673 if (jt->thread_state() != _thread_in_native) { 1674 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1675 // that requires ExecStack. Cannot enter safe point. Let's give up. 1676 warning("Unable to fix stack guard. Giving up."); 1677 } else { 1678 if (!LoadExecStackDllInVMThread) { 1679 // This is for the case where the DLL has an static 1680 // constructor function that executes JNI code. We cannot 1681 // load such DLLs in the VMThread. 1682 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1683 } 1684 1685 ThreadInVMfromNative tiv(jt); 1686 debug_only(VMNativeEntryWrapper vew;) 1687 1688 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1689 VMThread::execute(&op); 1690 if (LoadExecStackDllInVMThread) { 1691 result = op.loaded_library(); 1692 } 1693 load_attempted = true; 1694 } 1695 } 1696 } 1697 } 1698 1699 if (!load_attempted) { 1700 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1701 } 1702 1703 if (result != NULL) { 1704 // Successful loading 1705 return result; 1706 } 1707 1708 Elf32_Ehdr elf_head; 1709 int diag_msg_max_length=ebuflen-strlen(ebuf); 1710 char* diag_msg_buf=ebuf+strlen(ebuf); 1711 1712 if (diag_msg_max_length==0) { 1713 // No more space in ebuf for additional diagnostics message 1714 return NULL; 1715 } 1716 1717 1718 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1719 1720 if (file_descriptor < 0) { 1721 // Can't open library, report dlerror() message 1722 return NULL; 1723 } 1724 1725 bool failed_to_read_elf_head= 1726 (sizeof(elf_head)!= 1727 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1728 1729 ::close(file_descriptor); 1730 if (failed_to_read_elf_head) { 1731 // file i/o error - report dlerror() msg 1732 return NULL; 1733 } 1734 1735 typedef struct { 1736 Elf32_Half code; // Actual value as defined in elf.h 1737 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1738 unsigned char elf_class; // 32 or 64 bit 1739 unsigned char endianess; // MSB or LSB 1740 char* name; // String representation 1741 } arch_t; 1742 1743 #ifndef EM_486 1744 #define EM_486 6 /* Intel 80486 */ 1745 #endif 1746 #ifndef EM_AARCH64 1747 #define EM_AARCH64 183 /* ARM AARCH64 */ 1748 #endif 1749 1750 static const arch_t arch_array[]={ 1751 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1752 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1753 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1754 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1755 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1756 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1757 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1758 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1759 #if defined(VM_LITTLE_ENDIAN) 1760 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1761 #else 1762 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"}, 1763 #endif 1764 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1765 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1766 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1767 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1768 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1769 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1770 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1771 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1772 }; 1773 1774 #if (defined IA32) 1775 static Elf32_Half running_arch_code=EM_386; 1776 #elif (defined AMD64) 1777 static Elf32_Half running_arch_code=EM_X86_64; 1778 #elif (defined IA64) 1779 static Elf32_Half running_arch_code=EM_IA_64; 1780 #elif (defined __sparc) && (defined _LP64) 1781 static Elf32_Half running_arch_code=EM_SPARCV9; 1782 #elif (defined __sparc) && (!defined _LP64) 1783 static Elf32_Half running_arch_code=EM_SPARC; 1784 #elif (defined __powerpc64__) 1785 static Elf32_Half running_arch_code=EM_PPC64; 1786 #elif (defined __powerpc__) 1787 static Elf32_Half running_arch_code=EM_PPC; 1788 #elif (defined AARCH64) 1789 static Elf32_Half running_arch_code=EM_AARCH64; 1790 #elif (defined ARM) 1791 static Elf32_Half running_arch_code=EM_ARM; 1792 #elif (defined S390) 1793 static Elf32_Half running_arch_code=EM_S390; 1794 #elif (defined ALPHA) 1795 static Elf32_Half running_arch_code=EM_ALPHA; 1796 #elif (defined MIPSEL) 1797 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1798 #elif (defined PARISC) 1799 static Elf32_Half running_arch_code=EM_PARISC; 1800 #elif (defined MIPS) 1801 static Elf32_Half running_arch_code=EM_MIPS; 1802 #elif (defined M68K) 1803 static Elf32_Half running_arch_code=EM_68K; 1804 #else 1805 #error Method os::dll_load requires that one of following is defined:\ 1806 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc 1807 #endif 1808 1809 // Identify compatability class for VM's architecture and library's architecture 1810 // Obtain string descriptions for architectures 1811 1812 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1813 int running_arch_index=-1; 1814 1815 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1816 if (running_arch_code == arch_array[i].code) { 1817 running_arch_index = i; 1818 } 1819 if (lib_arch.code == arch_array[i].code) { 1820 lib_arch.compat_class = arch_array[i].compat_class; 1821 lib_arch.name = arch_array[i].name; 1822 } 1823 } 1824 1825 assert(running_arch_index != -1, 1826 "Didn't find running architecture code (running_arch_code) in arch_array"); 1827 if (running_arch_index == -1) { 1828 // Even though running architecture detection failed 1829 // we may still continue with reporting dlerror() message 1830 return NULL; 1831 } 1832 1833 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1834 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1835 return NULL; 1836 } 1837 1838 #ifndef S390 1839 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1840 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1841 return NULL; 1842 } 1843 #endif // !S390 1844 1845 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1846 if (lib_arch.name!=NULL) { 1847 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1848 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1849 lib_arch.name, arch_array[running_arch_index].name); 1850 } else { 1851 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1852 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1853 lib_arch.code, 1854 arch_array[running_arch_index].name); 1855 } 1856 } 1857 1858 return NULL; 1859 } 1860 1861 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1862 int ebuflen) { 1863 void * result = ::dlopen(filename, RTLD_LAZY); 1864 if (result == NULL) { 1865 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1866 ebuf[ebuflen-1] = '\0'; 1867 } 1868 return result; 1869 } 1870 1871 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1872 int ebuflen) { 1873 void * result = NULL; 1874 if (LoadExecStackDllInVMThread) { 1875 result = dlopen_helper(filename, ebuf, ebuflen); 1876 } 1877 1878 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1879 // library that requires an executable stack, or which does not have this 1880 // stack attribute set, dlopen changes the stack attribute to executable. The 1881 // read protection of the guard pages gets lost. 1882 // 1883 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1884 // may have been queued at the same time. 1885 1886 if (!_stack_is_executable) { 1887 JavaThread *jt = Threads::first(); 1888 1889 while (jt) { 1890 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1891 jt->stack_guards_enabled()) { // No pending stack overflow exceptions 1892 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) { 1893 warning("Attempt to reguard stack yellow zone failed."); 1894 } 1895 } 1896 jt = jt->next(); 1897 } 1898 } 1899 1900 return result; 1901 } 1902 1903 void* os::dll_lookup(void* handle, const char* name) { 1904 void* res = dlsym(handle, name); 1905 return res; 1906 } 1907 1908 void* os::get_default_process_handle() { 1909 return (void*)::dlopen(NULL, RTLD_LAZY); 1910 } 1911 1912 static bool _print_ascii_file(const char* filename, outputStream* st) { 1913 int fd = ::open(filename, O_RDONLY); 1914 if (fd == -1) { 1915 return false; 1916 } 1917 1918 char buf[33]; 1919 int bytes; 1920 buf[32] = '\0'; 1921 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) { 1922 st->print_raw(buf, bytes); 1923 } 1924 1925 ::close(fd); 1926 1927 return true; 1928 } 1929 1930 void os::print_dll_info(outputStream *st) { 1931 st->print_cr("Dynamic libraries:"); 1932 1933 char fname[32]; 1934 pid_t pid = os::Linux::gettid(); 1935 1936 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1937 1938 if (!_print_ascii_file(fname, st)) { 1939 st->print("Can not get library information for pid = %d\n", pid); 1940 } 1941 } 1942 1943 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1944 FILE *procmapsFile = NULL; 1945 1946 // Open the procfs maps file for the current process 1947 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1948 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1949 char line[PATH_MAX + 100]; 1950 1951 // Read line by line from 'file' 1952 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1953 u8 base, top, offset, inode; 1954 char permissions[5]; 1955 char device[6]; 1956 char name[PATH_MAX + 1]; 1957 1958 // Parse fields from line 1959 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1960 &base, &top, permissions, &offset, device, &inode, name); 1961 1962 // Filter by device id '00:00' so that we only get file system mapped files. 1963 if (strcmp(device, "00:00") != 0) { 1964 1965 // Call callback with the fields of interest 1966 if(callback(name, (address)base, (address)top, param)) { 1967 // Oops abort, callback aborted 1968 fclose(procmapsFile); 1969 return 1; 1970 } 1971 } 1972 } 1973 fclose(procmapsFile); 1974 } 1975 return 0; 1976 } 1977 1978 void os::print_os_info_brief(outputStream* st) { 1979 os::Linux::print_distro_info(st); 1980 1981 os::Posix::print_uname_info(st); 1982 1983 os::Linux::print_libversion_info(st); 1984 1985 } 1986 1987 void os::print_os_info(outputStream* st) { 1988 st->print("OS:"); 1989 1990 os::Linux::print_distro_info(st); 1991 1992 os::Posix::print_uname_info(st); 1993 1994 // Print warning if unsafe chroot environment detected 1995 if (unsafe_chroot_detected) { 1996 st->print("WARNING!! "); 1997 st->print_cr("%s", unstable_chroot_error); 1998 } 1999 2000 os::Linux::print_libversion_info(st); 2001 2002 os::Posix::print_rlimit_info(st); 2003 2004 os::Posix::print_load_average(st); 2005 2006 os::Linux::print_full_memory_info(st); 2007 } 2008 2009 // Try to identify popular distros. 2010 // Most Linux distributions have a /etc/XXX-release file, which contains 2011 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2012 // file that also contains the OS version string. Some have more than one 2013 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2014 // /etc/redhat-release.), so the order is important. 2015 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2016 // their own specific XXX-release file as well as a redhat-release file. 2017 // Because of this the XXX-release file needs to be searched for before the 2018 // redhat-release file. 2019 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the 2020 // search for redhat-release / SuSE-release needs to be before lsb-release. 2021 // Since the lsb-release file is the new standard it needs to be searched 2022 // before the older style release files. 2023 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2024 // next to last resort. The os-release file is a new standard that contains 2025 // distribution information and the system-release file seems to be an old 2026 // standard that has been replaced by the lsb-release and os-release files. 2027 // Searching for the debian_version file is the last resort. It contains 2028 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2029 // "Debian " is printed before the contents of the debian_version file. 2030 2031 const char* distro_files[] = { 2032 "/etc/oracle-release", 2033 "/etc/mandriva-release", 2034 "/etc/mandrake-release", 2035 "/etc/sun-release", 2036 "/etc/redhat-release", 2037 "/etc/SuSE-release", 2038 "/etc/lsb-release", 2039 "/etc/turbolinux-release", 2040 "/etc/gentoo-release", 2041 "/etc/ltib-release", 2042 "/etc/angstrom-version", 2043 "/etc/system-release", 2044 "/etc/os-release", 2045 NULL }; 2046 2047 void os::Linux::print_distro_info(outputStream* st) { 2048 for (int i = 0;; i++) { 2049 const char* file = distro_files[i]; 2050 if (file == NULL) { 2051 break; // done 2052 } 2053 // If file prints, we found it. 2054 if (_print_ascii_file(file, st)) { 2055 return; 2056 } 2057 } 2058 2059 if (file_exists("/etc/debian_version")) { 2060 st->print("Debian "); 2061 _print_ascii_file("/etc/debian_version", st); 2062 } else { 2063 st->print("Linux"); 2064 } 2065 st->cr(); 2066 } 2067 2068 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) { 2069 char buf[256]; 2070 while (fgets(buf, sizeof(buf), fp)) { 2071 // Edit out extra stuff in expected format 2072 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) { 2073 char* ptr = strstr(buf, "\""); // the name is in quotes 2074 if (ptr != NULL) { 2075 ptr++; // go beyond first quote 2076 char* nl = strchr(ptr, '\"'); 2077 if (nl != NULL) *nl = '\0'; 2078 strncpy(distro, ptr, length); 2079 } else { 2080 ptr = strstr(buf, "="); 2081 ptr++; // go beyond equals then 2082 char* nl = strchr(ptr, '\n'); 2083 if (nl != NULL) *nl = '\0'; 2084 strncpy(distro, ptr, length); 2085 } 2086 return; 2087 } else if (get_first_line) { 2088 char* nl = strchr(buf, '\n'); 2089 if (nl != NULL) *nl = '\0'; 2090 strncpy(distro, buf, length); 2091 return; 2092 } 2093 } 2094 // print last line and close 2095 char* nl = strchr(buf, '\n'); 2096 if (nl != NULL) *nl = '\0'; 2097 strncpy(distro, buf, length); 2098 } 2099 2100 static void parse_os_info(char* distro, size_t length, const char* file) { 2101 FILE* fp = fopen(file, "r"); 2102 if (fp != NULL) { 2103 // if suse format, print out first line 2104 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0); 2105 parse_os_info_helper(fp, distro, length, get_first_line); 2106 fclose(fp); 2107 } 2108 } 2109 2110 void os::get_summary_os_info(char* buf, size_t buflen) { 2111 for (int i = 0;; i++) { 2112 const char* file = distro_files[i]; 2113 if (file == NULL) { 2114 break; // ran out of distro_files 2115 } 2116 if (file_exists(file)) { 2117 parse_os_info(buf, buflen, file); 2118 return; 2119 } 2120 } 2121 // special case for debian 2122 if (file_exists("/etc/debian_version")) { 2123 strncpy(buf, "Debian ", buflen); 2124 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2125 } else { 2126 strncpy(buf, "Linux", buflen); 2127 } 2128 } 2129 2130 void os::Linux::print_libversion_info(outputStream* st) { 2131 // libc, pthread 2132 st->print("libc:"); 2133 st->print("%s ", os::Linux::glibc_version()); 2134 st->print("%s ", os::Linux::libpthread_version()); 2135 st->cr(); 2136 } 2137 2138 void os::Linux::print_full_memory_info(outputStream* st) { 2139 st->print("\n/proc/meminfo:\n"); 2140 _print_ascii_file("/proc/meminfo", st); 2141 st->cr(); 2142 } 2143 2144 void os::print_memory_info(outputStream* st) { 2145 2146 st->print("Memory:"); 2147 st->print(" %dk page", os::vm_page_size()>>10); 2148 2149 // values in struct sysinfo are "unsigned long" 2150 struct sysinfo si; 2151 sysinfo(&si); 2152 2153 st->print(", physical " UINT64_FORMAT "k", 2154 os::physical_memory() >> 10); 2155 st->print("(" UINT64_FORMAT "k free)", 2156 os::available_memory() >> 10); 2157 st->print(", swap " UINT64_FORMAT "k", 2158 ((jlong)si.totalswap * si.mem_unit) >> 10); 2159 st->print("(" UINT64_FORMAT "k free)", 2160 ((jlong)si.freeswap * si.mem_unit) >> 10); 2161 st->cr(); 2162 } 2163 2164 // Print the first "model name" line and the first "flags" line 2165 // that we find and nothing more. We assume "model name" comes 2166 // before "flags" so if we find a second "model name", then the 2167 // "flags" field is considered missing. 2168 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2169 #if defined(IA32) || defined(AMD64) 2170 // Other platforms have less repetitive cpuinfo files 2171 FILE *fp = fopen("/proc/cpuinfo", "r"); 2172 if (fp) { 2173 while (!feof(fp)) { 2174 if (fgets(buf, buflen, fp)) { 2175 // Assume model name comes before flags 2176 bool model_name_printed = false; 2177 if (strstr(buf, "model name") != NULL) { 2178 if (!model_name_printed) { 2179 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n"); 2180 st->print_raw(buf); 2181 model_name_printed = true; 2182 } else { 2183 // model name printed but not flags? Odd, just return 2184 fclose(fp); 2185 return true; 2186 } 2187 } 2188 // print the flags line too 2189 if (strstr(buf, "flags") != NULL) { 2190 st->print_raw(buf); 2191 fclose(fp); 2192 return true; 2193 } 2194 } 2195 } 2196 fclose(fp); 2197 } 2198 #endif // x86 platforms 2199 return false; 2200 } 2201 2202 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2203 // Only print the model name if the platform provides this as a summary 2204 if (!print_model_name_and_flags(st, buf, buflen)) { 2205 st->print("\n/proc/cpuinfo:\n"); 2206 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2207 st->print_cr(" <Not Available>"); 2208 } 2209 } 2210 } 2211 2212 #if defined(AMD64) || defined(IA32) || defined(X32) 2213 const char* search_string = "model name"; 2214 #elif defined(PPC64) 2215 const char* search_string = "cpu"; 2216 #elif defined(S390) 2217 const char* search_string = "processor"; 2218 #elif defined(SPARC) 2219 const char* search_string = "cpu"; 2220 #else 2221 const char* search_string = "Processor"; 2222 #endif 2223 2224 // Parses the cpuinfo file for string representing the model name. 2225 void os::get_summary_cpu_info(char* cpuinfo, size_t length) { 2226 FILE* fp = fopen("/proc/cpuinfo", "r"); 2227 if (fp != NULL) { 2228 while (!feof(fp)) { 2229 char buf[256]; 2230 if (fgets(buf, sizeof(buf), fp)) { 2231 char* start = strstr(buf, search_string); 2232 if (start != NULL) { 2233 char *ptr = start + strlen(search_string); 2234 char *end = buf + strlen(buf); 2235 while (ptr != end) { 2236 // skip whitespace and colon for the rest of the name. 2237 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') { 2238 break; 2239 } 2240 ptr++; 2241 } 2242 if (ptr != end) { 2243 // reasonable string, get rid of newline and keep the rest 2244 char* nl = strchr(buf, '\n'); 2245 if (nl != NULL) *nl = '\0'; 2246 strncpy(cpuinfo, ptr, length); 2247 fclose(fp); 2248 return; 2249 } 2250 } 2251 } 2252 } 2253 fclose(fp); 2254 } 2255 // cpuinfo not found or parsing failed, just print generic string. The entire 2256 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86) 2257 #if defined(AARCH64) 2258 strncpy(cpuinfo, "AArch64", length); 2259 #elif defined(AMD64) 2260 strncpy(cpuinfo, "x86_64", length); 2261 #elif defined(ARM) // Order wrt. AARCH64 is relevant! 2262 strncpy(cpuinfo, "ARM", length); 2263 #elif defined(IA32) 2264 strncpy(cpuinfo, "x86_32", length); 2265 #elif defined(IA64) 2266 strncpy(cpuinfo, "IA64", length); 2267 #elif defined(PPC) 2268 strncpy(cpuinfo, "PPC64", length); 2269 #elif defined(S390) 2270 strncpy(cpuinfo, "S390", length); 2271 #elif defined(SPARC) 2272 strncpy(cpuinfo, "sparcv9", length); 2273 #elif defined(ZERO_LIBARCH) 2274 strncpy(cpuinfo, ZERO_LIBARCH, length); 2275 #else 2276 strncpy(cpuinfo, "unknown", length); 2277 #endif 2278 } 2279 2280 static void print_signal_handler(outputStream* st, int sig, 2281 char* buf, size_t buflen); 2282 2283 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2284 st->print_cr("Signal Handlers:"); 2285 print_signal_handler(st, SIGSEGV, buf, buflen); 2286 print_signal_handler(st, SIGBUS , buf, buflen); 2287 print_signal_handler(st, SIGFPE , buf, buflen); 2288 print_signal_handler(st, SIGPIPE, buf, buflen); 2289 print_signal_handler(st, SIGXFSZ, buf, buflen); 2290 print_signal_handler(st, SIGILL , buf, buflen); 2291 print_signal_handler(st, SR_signum, buf, buflen); 2292 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2293 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2294 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2295 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2296 #if defined(PPC64) 2297 print_signal_handler(st, SIGTRAP, buf, buflen); 2298 #endif 2299 } 2300 2301 static char saved_jvm_path[MAXPATHLEN] = {0}; 2302 2303 // Find the full path to the current module, libjvm.so 2304 void os::jvm_path(char *buf, jint buflen) { 2305 // Error checking. 2306 if (buflen < MAXPATHLEN) { 2307 assert(false, "must use a large-enough buffer"); 2308 buf[0] = '\0'; 2309 return; 2310 } 2311 // Lazy resolve the path to current module. 2312 if (saved_jvm_path[0] != 0) { 2313 strcpy(buf, saved_jvm_path); 2314 return; 2315 } 2316 2317 char dli_fname[MAXPATHLEN]; 2318 bool ret = dll_address_to_library_name( 2319 CAST_FROM_FN_PTR(address, os::jvm_path), 2320 dli_fname, sizeof(dli_fname), NULL); 2321 assert(ret, "cannot locate libjvm"); 2322 char *rp = NULL; 2323 if (ret && dli_fname[0] != '\0') { 2324 rp = realpath(dli_fname, buf); 2325 } 2326 if (rp == NULL) { 2327 return; 2328 } 2329 2330 if (Arguments::sun_java_launcher_is_altjvm()) { 2331 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2332 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so". 2333 // If "/jre/lib/" appears at the right place in the string, then 2334 // assume we are installed in a JDK and we're done. Otherwise, check 2335 // for a JAVA_HOME environment variable and fix up the path so it 2336 // looks like libjvm.so is installed there (append a fake suffix 2337 // hotspot/libjvm.so). 2338 const char *p = buf + strlen(buf) - 1; 2339 for (int count = 0; p > buf && count < 5; ++count) { 2340 for (--p; p > buf && *p != '/'; --p) 2341 /* empty */ ; 2342 } 2343 2344 if (strncmp(p, "/jre/lib/", 9) != 0) { 2345 // Look for JAVA_HOME in the environment. 2346 char* java_home_var = ::getenv("JAVA_HOME"); 2347 if (java_home_var != NULL && java_home_var[0] != 0) { 2348 char* jrelib_p; 2349 int len; 2350 2351 // Check the current module name "libjvm.so". 2352 p = strrchr(buf, '/'); 2353 if (p == NULL) { 2354 return; 2355 } 2356 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2357 2358 rp = realpath(java_home_var, buf); 2359 if (rp == NULL) { 2360 return; 2361 } 2362 2363 // determine if this is a legacy image or modules image 2364 // modules image doesn't have "jre" subdirectory 2365 len = strlen(buf); 2366 assert(len < buflen, "Ran out of buffer room"); 2367 jrelib_p = buf + len; 2368 snprintf(jrelib_p, buflen-len, "/jre/lib"); 2369 if (0 != access(buf, F_OK)) { 2370 snprintf(jrelib_p, buflen-len, "/lib"); 2371 } 2372 2373 if (0 == access(buf, F_OK)) { 2374 // Use current module name "libjvm.so" 2375 len = strlen(buf); 2376 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2377 } else { 2378 // Go back to path of .so 2379 rp = realpath(dli_fname, buf); 2380 if (rp == NULL) { 2381 return; 2382 } 2383 } 2384 } 2385 } 2386 } 2387 2388 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2389 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2390 } 2391 2392 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2393 // no prefix required, not even "_" 2394 } 2395 2396 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2397 // no suffix required 2398 } 2399 2400 //////////////////////////////////////////////////////////////////////////////// 2401 // sun.misc.Signal support 2402 2403 static volatile jint sigint_count = 0; 2404 2405 static void UserHandler(int sig, void *siginfo, void *context) { 2406 // 4511530 - sem_post is serialized and handled by the manager thread. When 2407 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2408 // don't want to flood the manager thread with sem_post requests. 2409 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2410 return; 2411 } 2412 2413 // Ctrl-C is pressed during error reporting, likely because the error 2414 // handler fails to abort. Let VM die immediately. 2415 if (sig == SIGINT && is_error_reported()) { 2416 os::die(); 2417 } 2418 2419 os::signal_notify(sig); 2420 } 2421 2422 void* os::user_handler() { 2423 return CAST_FROM_FN_PTR(void*, UserHandler); 2424 } 2425 2426 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2427 struct timespec ts; 2428 // Semaphore's are always associated with CLOCK_REALTIME 2429 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2430 // see unpackTime for discussion on overflow checking 2431 if (sec >= MAX_SECS) { 2432 ts.tv_sec += MAX_SECS; 2433 ts.tv_nsec = 0; 2434 } else { 2435 ts.tv_sec += sec; 2436 ts.tv_nsec += nsec; 2437 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2438 ts.tv_nsec -= NANOSECS_PER_SEC; 2439 ++ts.tv_sec; // note: this must be <= max_secs 2440 } 2441 } 2442 2443 return ts; 2444 } 2445 2446 extern "C" { 2447 typedef void (*sa_handler_t)(int); 2448 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2449 } 2450 2451 void* os::signal(int signal_number, void* handler) { 2452 struct sigaction sigAct, oldSigAct; 2453 2454 sigfillset(&(sigAct.sa_mask)); 2455 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2456 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2457 2458 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2459 // -1 means registration failed 2460 return (void *)-1; 2461 } 2462 2463 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2464 } 2465 2466 void os::signal_raise(int signal_number) { 2467 ::raise(signal_number); 2468 } 2469 2470 // The following code is moved from os.cpp for making this 2471 // code platform specific, which it is by its very nature. 2472 2473 // Will be modified when max signal is changed to be dynamic 2474 int os::sigexitnum_pd() { 2475 return NSIG; 2476 } 2477 2478 // a counter for each possible signal value 2479 static volatile jint pending_signals[NSIG+1] = { 0 }; 2480 2481 // Linux(POSIX) specific hand shaking semaphore. 2482 static sem_t sig_sem; 2483 static PosixSemaphore sr_semaphore; 2484 2485 void os::signal_init_pd() { 2486 // Initialize signal structures 2487 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2488 2489 // Initialize signal semaphore 2490 ::sem_init(&sig_sem, 0, 0); 2491 } 2492 2493 void os::signal_notify(int sig) { 2494 Atomic::inc(&pending_signals[sig]); 2495 ::sem_post(&sig_sem); 2496 } 2497 2498 static int check_pending_signals(bool wait) { 2499 Atomic::store(0, &sigint_count); 2500 for (;;) { 2501 for (int i = 0; i < NSIG + 1; i++) { 2502 jint n = pending_signals[i]; 2503 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2504 return i; 2505 } 2506 } 2507 if (!wait) { 2508 return -1; 2509 } 2510 JavaThread *thread = JavaThread::current(); 2511 ThreadBlockInVM tbivm(thread); 2512 2513 bool threadIsSuspended; 2514 do { 2515 thread->set_suspend_equivalent(); 2516 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2517 ::sem_wait(&sig_sem); 2518 2519 // were we externally suspended while we were waiting? 2520 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2521 if (threadIsSuspended) { 2522 // The semaphore has been incremented, but while we were waiting 2523 // another thread suspended us. We don't want to continue running 2524 // while suspended because that would surprise the thread that 2525 // suspended us. 2526 ::sem_post(&sig_sem); 2527 2528 thread->java_suspend_self(); 2529 } 2530 } while (threadIsSuspended); 2531 } 2532 } 2533 2534 int os::signal_lookup() { 2535 return check_pending_signals(false); 2536 } 2537 2538 int os::signal_wait() { 2539 return check_pending_signals(true); 2540 } 2541 2542 //////////////////////////////////////////////////////////////////////////////// 2543 // Virtual Memory 2544 2545 int os::vm_page_size() { 2546 // Seems redundant as all get out 2547 assert(os::Linux::page_size() != -1, "must call os::init"); 2548 return os::Linux::page_size(); 2549 } 2550 2551 // Solaris allocates memory by pages. 2552 int os::vm_allocation_granularity() { 2553 assert(os::Linux::page_size() != -1, "must call os::init"); 2554 return os::Linux::page_size(); 2555 } 2556 2557 // Rationale behind this function: 2558 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2559 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2560 // samples for JITted code. Here we create private executable mapping over the code cache 2561 // and then we can use standard (well, almost, as mapping can change) way to provide 2562 // info for the reporting script by storing timestamp and location of symbol 2563 void linux_wrap_code(char* base, size_t size) { 2564 static volatile jint cnt = 0; 2565 2566 if (!UseOprofile) { 2567 return; 2568 } 2569 2570 char buf[PATH_MAX+1]; 2571 int num = Atomic::add(1, &cnt); 2572 2573 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2574 os::get_temp_directory(), os::current_process_id(), num); 2575 unlink(buf); 2576 2577 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2578 2579 if (fd != -1) { 2580 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2581 if (rv != (off_t)-1) { 2582 if (::write(fd, "", 1) == 1) { 2583 mmap(base, size, 2584 PROT_READ|PROT_WRITE|PROT_EXEC, 2585 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2586 } 2587 } 2588 ::close(fd); 2589 unlink(buf); 2590 } 2591 } 2592 2593 static bool recoverable_mmap_error(int err) { 2594 // See if the error is one we can let the caller handle. This 2595 // list of errno values comes from JBS-6843484. I can't find a 2596 // Linux man page that documents this specific set of errno 2597 // values so while this list currently matches Solaris, it may 2598 // change as we gain experience with this failure mode. 2599 switch (err) { 2600 case EBADF: 2601 case EINVAL: 2602 case ENOTSUP: 2603 // let the caller deal with these errors 2604 return true; 2605 2606 default: 2607 // Any remaining errors on this OS can cause our reserved mapping 2608 // to be lost. That can cause confusion where different data 2609 // structures think they have the same memory mapped. The worst 2610 // scenario is if both the VM and a library think they have the 2611 // same memory mapped. 2612 return false; 2613 } 2614 } 2615 2616 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2617 int err) { 2618 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2619 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2620 os::strerror(err), err); 2621 } 2622 2623 static void warn_fail_commit_memory(char* addr, size_t size, 2624 size_t alignment_hint, bool exec, 2625 int err) { 2626 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2627 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2628 alignment_hint, exec, os::strerror(err), err); 2629 } 2630 2631 // NOTE: Linux kernel does not really reserve the pages for us. 2632 // All it does is to check if there are enough free pages 2633 // left at the time of mmap(). This could be a potential 2634 // problem. 2635 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2636 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2637 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2638 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2639 if (res != (uintptr_t) MAP_FAILED) { 2640 if (UseNUMAInterleaving) { 2641 numa_make_global(addr, size); 2642 } 2643 return 0; 2644 } 2645 2646 int err = errno; // save errno from mmap() call above 2647 2648 if (!recoverable_mmap_error(err)) { 2649 warn_fail_commit_memory(addr, size, exec, err); 2650 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2651 } 2652 2653 return err; 2654 } 2655 2656 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2657 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2658 } 2659 2660 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2661 const char* mesg) { 2662 assert(mesg != NULL, "mesg must be specified"); 2663 int err = os::Linux::commit_memory_impl(addr, size, exec); 2664 if (err != 0) { 2665 // the caller wants all commit errors to exit with the specified mesg: 2666 warn_fail_commit_memory(addr, size, exec, err); 2667 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2668 } 2669 } 2670 2671 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2672 #ifndef MAP_HUGETLB 2673 #define MAP_HUGETLB 0x40000 2674 #endif 2675 2676 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2677 #ifndef MADV_HUGEPAGE 2678 #define MADV_HUGEPAGE 14 2679 #endif 2680 2681 int os::Linux::commit_memory_impl(char* addr, size_t size, 2682 size_t alignment_hint, bool exec) { 2683 int err = os::Linux::commit_memory_impl(addr, size, exec); 2684 if (err == 0) { 2685 realign_memory(addr, size, alignment_hint); 2686 } 2687 return err; 2688 } 2689 2690 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2691 bool exec) { 2692 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2693 } 2694 2695 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2696 size_t alignment_hint, bool exec, 2697 const char* mesg) { 2698 assert(mesg != NULL, "mesg must be specified"); 2699 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2700 if (err != 0) { 2701 // the caller wants all commit errors to exit with the specified mesg: 2702 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2703 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2704 } 2705 } 2706 2707 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2708 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2709 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2710 // be supported or the memory may already be backed by huge pages. 2711 ::madvise(addr, bytes, MADV_HUGEPAGE); 2712 } 2713 } 2714 2715 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2716 // This method works by doing an mmap over an existing mmaping and effectively discarding 2717 // the existing pages. However it won't work for SHM-based large pages that cannot be 2718 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2719 // small pages on top of the SHM segment. This method always works for small pages, so we 2720 // allow that in any case. 2721 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2722 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2723 } 2724 } 2725 2726 void os::numa_make_global(char *addr, size_t bytes) { 2727 Linux::numa_interleave_memory(addr, bytes); 2728 } 2729 2730 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2731 // bind policy to MPOL_PREFERRED for the current thread. 2732 #define USE_MPOL_PREFERRED 0 2733 2734 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2735 // To make NUMA and large pages more robust when both enabled, we need to ease 2736 // the requirements on where the memory should be allocated. MPOL_BIND is the 2737 // default policy and it will force memory to be allocated on the specified 2738 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2739 // the specified node, but will not force it. Using this policy will prevent 2740 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2741 // free large pages. 2742 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2743 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2744 } 2745 2746 bool os::numa_topology_changed() { return false; } 2747 2748 size_t os::numa_get_groups_num() { 2749 int max_node = Linux::numa_max_node(); 2750 return max_node > 0 ? max_node + 1 : 1; 2751 } 2752 2753 int os::numa_get_group_id() { 2754 int cpu_id = Linux::sched_getcpu(); 2755 if (cpu_id != -1) { 2756 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2757 if (lgrp_id != -1) { 2758 return lgrp_id; 2759 } 2760 } 2761 return 0; 2762 } 2763 2764 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2765 for (size_t i = 0; i < size; i++) { 2766 ids[i] = i; 2767 } 2768 return size; 2769 } 2770 2771 bool os::get_page_info(char *start, page_info* info) { 2772 return false; 2773 } 2774 2775 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2776 page_info* page_found) { 2777 return end; 2778 } 2779 2780 2781 int os::Linux::sched_getcpu_syscall(void) { 2782 unsigned int cpu = 0; 2783 int retval = -1; 2784 2785 #if defined(IA32) 2786 #ifndef SYS_getcpu 2787 #define SYS_getcpu 318 2788 #endif 2789 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2790 #elif defined(AMD64) 2791 // Unfortunately we have to bring all these macros here from vsyscall.h 2792 // to be able to compile on old linuxes. 2793 #define __NR_vgetcpu 2 2794 #define VSYSCALL_START (-10UL << 20) 2795 #define VSYSCALL_SIZE 1024 2796 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2797 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2798 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2799 retval = vgetcpu(&cpu, NULL, NULL); 2800 #endif 2801 2802 return (retval == -1) ? retval : cpu; 2803 } 2804 2805 // Something to do with the numa-aware allocator needs these symbols 2806 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2807 extern "C" JNIEXPORT void numa_error(char *where) { } 2808 2809 2810 // If we are running with libnuma version > 2, then we should 2811 // be trying to use symbols with versions 1.1 2812 // If we are running with earlier version, which did not have symbol versions, 2813 // we should use the base version. 2814 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2815 typedef void* (*dlvsym_func_type)(void* handle, const char* name, const char* version); 2816 static dlvsym_func_type dlvsym_func; 2817 static bool initialized = false; 2818 2819 if (!initialized) { 2820 dlvsym_func = (dlvsym_func_type)dlsym(RTLD_NEXT, "dlvsym"); 2821 initialized = true; 2822 } 2823 2824 if (dlvsym_func != NULL) { 2825 void *f = dlvsym_func(handle, name, "libnuma_1.1"); 2826 if (f != NULL) { 2827 return f; 2828 } 2829 } 2830 2831 return dlsym(handle, name); 2832 } 2833 2834 bool os::Linux::libnuma_init() { 2835 // sched_getcpu() should be in libc. 2836 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2837 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2838 2839 // If it's not, try a direct syscall. 2840 if (sched_getcpu() == -1) { 2841 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2842 (void*)&sched_getcpu_syscall)); 2843 } 2844 2845 if (sched_getcpu() != -1) { // Does it work? 2846 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2847 if (handle != NULL) { 2848 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2849 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2850 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2851 libnuma_dlsym(handle, "numa_max_node"))); 2852 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2853 libnuma_dlsym(handle, "numa_available"))); 2854 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2855 libnuma_dlsym(handle, "numa_tonode_memory"))); 2856 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2857 libnuma_dlsym(handle, "numa_interleave_memory"))); 2858 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2859 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2860 2861 2862 if (numa_available() != -1) { 2863 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2864 // Create a cpu -> node mapping 2865 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2866 rebuild_cpu_to_node_map(); 2867 return true; 2868 } 2869 } 2870 } 2871 return false; 2872 } 2873 2874 size_t os::Linux::default_guard_size(os::ThreadType thr_type) { 2875 // Creating guard page is very expensive. Java thread has HotSpot 2876 // guard pages, only enable glibc guard page for non-Java threads. 2877 // (Remember: compiler thread is a Java thread, too!) 2878 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size()); 2879 } 2880 2881 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2882 // The table is later used in get_node_by_cpu(). 2883 void os::Linux::rebuild_cpu_to_node_map() { 2884 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2885 // in libnuma (possible values are starting from 16, 2886 // and continuing up with every other power of 2, but less 2887 // than the maximum number of CPUs supported by kernel), and 2888 // is a subject to change (in libnuma version 2 the requirements 2889 // are more reasonable) we'll just hardcode the number they use 2890 // in the library. 2891 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2892 2893 size_t cpu_num = processor_count(); 2894 size_t cpu_map_size = NCPUS / BitsPerCLong; 2895 size_t cpu_map_valid_size = 2896 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2897 2898 cpu_to_node()->clear(); 2899 cpu_to_node()->at_grow(cpu_num - 1); 2900 size_t node_num = numa_get_groups_num(); 2901 2902 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2903 for (size_t i = 0; i < node_num; i++) { 2904 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2905 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2906 if (cpu_map[j] != 0) { 2907 for (size_t k = 0; k < BitsPerCLong; k++) { 2908 if (cpu_map[j] & (1UL << k)) { 2909 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2910 } 2911 } 2912 } 2913 } 2914 } 2915 } 2916 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2917 } 2918 2919 int os::Linux::get_node_by_cpu(int cpu_id) { 2920 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2921 return cpu_to_node()->at(cpu_id); 2922 } 2923 return -1; 2924 } 2925 2926 GrowableArray<int>* os::Linux::_cpu_to_node; 2927 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2928 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2929 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2930 os::Linux::numa_available_func_t os::Linux::_numa_available; 2931 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2932 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2933 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2934 unsigned long* os::Linux::_numa_all_nodes; 2935 2936 bool os::pd_uncommit_memory(char* addr, size_t size) { 2937 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2938 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2939 return res != (uintptr_t) MAP_FAILED; 2940 } 2941 2942 static address get_stack_commited_bottom(address bottom, size_t size) { 2943 address nbot = bottom; 2944 address ntop = bottom + size; 2945 2946 size_t page_sz = os::vm_page_size(); 2947 unsigned pages = size / page_sz; 2948 2949 unsigned char vec[1]; 2950 unsigned imin = 1, imax = pages + 1, imid; 2951 int mincore_return_value = 0; 2952 2953 assert(imin <= imax, "Unexpected page size"); 2954 2955 while (imin < imax) { 2956 imid = (imax + imin) / 2; 2957 nbot = ntop - (imid * page_sz); 2958 2959 // Use a trick with mincore to check whether the page is mapped or not. 2960 // mincore sets vec to 1 if page resides in memory and to 0 if page 2961 // is swapped output but if page we are asking for is unmapped 2962 // it returns -1,ENOMEM 2963 mincore_return_value = mincore(nbot, page_sz, vec); 2964 2965 if (mincore_return_value == -1) { 2966 // Page is not mapped go up 2967 // to find first mapped page 2968 if (errno != EAGAIN) { 2969 assert(errno == ENOMEM, "Unexpected mincore errno"); 2970 imax = imid; 2971 } 2972 } else { 2973 // Page is mapped go down 2974 // to find first not mapped page 2975 imin = imid + 1; 2976 } 2977 } 2978 2979 nbot = nbot + page_sz; 2980 2981 // Adjust stack bottom one page up if last checked page is not mapped 2982 if (mincore_return_value == -1) { 2983 nbot = nbot + page_sz; 2984 } 2985 2986 return nbot; 2987 } 2988 2989 2990 // Linux uses a growable mapping for the stack, and if the mapping for 2991 // the stack guard pages is not removed when we detach a thread the 2992 // stack cannot grow beyond the pages where the stack guard was 2993 // mapped. If at some point later in the process the stack expands to 2994 // that point, the Linux kernel cannot expand the stack any further 2995 // because the guard pages are in the way, and a segfault occurs. 2996 // 2997 // However, it's essential not to split the stack region by unmapping 2998 // a region (leaving a hole) that's already part of the stack mapping, 2999 // so if the stack mapping has already grown beyond the guard pages at 3000 // the time we create them, we have to truncate the stack mapping. 3001 // So, we need to know the extent of the stack mapping when 3002 // create_stack_guard_pages() is called. 3003 3004 // We only need this for stacks that are growable: at the time of 3005 // writing thread stacks don't use growable mappings (i.e. those 3006 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3007 // only applies to the main thread. 3008 3009 // If the (growable) stack mapping already extends beyond the point 3010 // where we're going to put our guard pages, truncate the mapping at 3011 // that point by munmap()ping it. This ensures that when we later 3012 // munmap() the guard pages we don't leave a hole in the stack 3013 // mapping. This only affects the main/initial thread 3014 3015 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3016 if (os::Linux::is_initial_thread()) { 3017 // As we manually grow stack up to bottom inside create_attached_thread(), 3018 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3019 // we don't need to do anything special. 3020 // Check it first, before calling heavy function. 3021 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3022 unsigned char vec[1]; 3023 3024 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3025 // Fallback to slow path on all errors, including EAGAIN 3026 stack_extent = (uintptr_t) get_stack_commited_bottom( 3027 os::Linux::initial_thread_stack_bottom(), 3028 (size_t)addr - stack_extent); 3029 } 3030 3031 if (stack_extent < (uintptr_t)addr) { 3032 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3033 } 3034 } 3035 3036 return os::commit_memory(addr, size, !ExecMem); 3037 } 3038 3039 // If this is a growable mapping, remove the guard pages entirely by 3040 // munmap()ping them. If not, just call uncommit_memory(). This only 3041 // affects the main/initial thread, but guard against future OS changes 3042 // It's safe to always unmap guard pages for initial thread because we 3043 // always place it right after end of the mapped region 3044 3045 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3046 uintptr_t stack_extent, stack_base; 3047 3048 if (os::Linux::is_initial_thread()) { 3049 return ::munmap(addr, size) == 0; 3050 } 3051 3052 return os::uncommit_memory(addr, size); 3053 } 3054 3055 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3056 // at 'requested_addr'. If there are existing memory mappings at the same 3057 // location, however, they will be overwritten. If 'fixed' is false, 3058 // 'requested_addr' is only treated as a hint, the return value may or 3059 // may not start from the requested address. Unlike Linux mmap(), this 3060 // function returns NULL to indicate failure. 3061 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3062 char * addr; 3063 int flags; 3064 3065 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3066 if (fixed) { 3067 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3068 flags |= MAP_FIXED; 3069 } 3070 3071 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3072 // touch an uncommitted page. Otherwise, the read/write might 3073 // succeed if we have enough swap space to back the physical page. 3074 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3075 flags, -1, 0); 3076 3077 return addr == MAP_FAILED ? NULL : addr; 3078 } 3079 3080 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3081 // (req_addr != NULL) or with a given alignment. 3082 // - bytes shall be a multiple of alignment. 3083 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3084 // - alignment sets the alignment at which memory shall be allocated. 3085 // It must be a multiple of allocation granularity. 3086 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3087 // req_addr or NULL. 3088 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3089 3090 size_t extra_size = bytes; 3091 if (req_addr == NULL && alignment > 0) { 3092 extra_size += alignment; 3093 } 3094 3095 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3096 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3097 -1, 0); 3098 if (start == MAP_FAILED) { 3099 start = NULL; 3100 } else { 3101 if (req_addr != NULL) { 3102 if (start != req_addr) { 3103 ::munmap(start, extra_size); 3104 start = NULL; 3105 } 3106 } else { 3107 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3108 char* const end_aligned = start_aligned + bytes; 3109 char* const end = start + extra_size; 3110 if (start_aligned > start) { 3111 ::munmap(start, start_aligned - start); 3112 } 3113 if (end_aligned < end) { 3114 ::munmap(end_aligned, end - end_aligned); 3115 } 3116 start = start_aligned; 3117 } 3118 } 3119 return start; 3120 } 3121 3122 static int anon_munmap(char * addr, size_t size) { 3123 return ::munmap(addr, size) == 0; 3124 } 3125 3126 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3127 size_t alignment_hint) { 3128 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3129 } 3130 3131 bool os::pd_release_memory(char* addr, size_t size) { 3132 return anon_munmap(addr, size); 3133 } 3134 3135 static bool linux_mprotect(char* addr, size_t size, int prot) { 3136 // Linux wants the mprotect address argument to be page aligned. 3137 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3138 3139 // According to SUSv3, mprotect() should only be used with mappings 3140 // established by mmap(), and mmap() always maps whole pages. Unaligned 3141 // 'addr' likely indicates problem in the VM (e.g. trying to change 3142 // protection of malloc'ed or statically allocated memory). Check the 3143 // caller if you hit this assert. 3144 assert(addr == bottom, "sanity check"); 3145 3146 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3147 return ::mprotect(bottom, size, prot) == 0; 3148 } 3149 3150 // Set protections specified 3151 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3152 bool is_committed) { 3153 unsigned int p = 0; 3154 switch (prot) { 3155 case MEM_PROT_NONE: p = PROT_NONE; break; 3156 case MEM_PROT_READ: p = PROT_READ; break; 3157 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3158 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3159 default: 3160 ShouldNotReachHere(); 3161 } 3162 // is_committed is unused. 3163 return linux_mprotect(addr, bytes, p); 3164 } 3165 3166 bool os::guard_memory(char* addr, size_t size) { 3167 return linux_mprotect(addr, size, PROT_NONE); 3168 } 3169 3170 bool os::unguard_memory(char* addr, size_t size) { 3171 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3172 } 3173 3174 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3175 size_t page_size) { 3176 bool result = false; 3177 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3178 MAP_ANONYMOUS|MAP_PRIVATE, 3179 -1, 0); 3180 if (p != MAP_FAILED) { 3181 void *aligned_p = align_ptr_up(p, page_size); 3182 3183 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3184 3185 munmap(p, page_size * 2); 3186 } 3187 3188 if (warn && !result) { 3189 warning("TransparentHugePages is not supported by the operating system."); 3190 } 3191 3192 return result; 3193 } 3194 3195 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3196 bool result = false; 3197 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3198 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3199 -1, 0); 3200 3201 if (p != MAP_FAILED) { 3202 // We don't know if this really is a huge page or not. 3203 FILE *fp = fopen("/proc/self/maps", "r"); 3204 if (fp) { 3205 while (!feof(fp)) { 3206 char chars[257]; 3207 long x = 0; 3208 if (fgets(chars, sizeof(chars), fp)) { 3209 if (sscanf(chars, "%lx-%*x", &x) == 1 3210 && x == (long)p) { 3211 if (strstr (chars, "hugepage")) { 3212 result = true; 3213 break; 3214 } 3215 } 3216 } 3217 } 3218 fclose(fp); 3219 } 3220 munmap(p, page_size); 3221 } 3222 3223 if (warn && !result) { 3224 warning("HugeTLBFS is not supported by the operating system."); 3225 } 3226 3227 return result; 3228 } 3229 3230 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3231 // 3232 // From the coredump_filter documentation: 3233 // 3234 // - (bit 0) anonymous private memory 3235 // - (bit 1) anonymous shared memory 3236 // - (bit 2) file-backed private memory 3237 // - (bit 3) file-backed shared memory 3238 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3239 // effective only if the bit 2 is cleared) 3240 // - (bit 5) hugetlb private memory 3241 // - (bit 6) hugetlb shared memory 3242 // 3243 static void set_coredump_filter(void) { 3244 FILE *f; 3245 long cdm; 3246 3247 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3248 return; 3249 } 3250 3251 if (fscanf(f, "%lx", &cdm) != 1) { 3252 fclose(f); 3253 return; 3254 } 3255 3256 rewind(f); 3257 3258 if ((cdm & LARGEPAGES_BIT) == 0) { 3259 cdm |= LARGEPAGES_BIT; 3260 fprintf(f, "%#lx", cdm); 3261 } 3262 3263 fclose(f); 3264 } 3265 3266 // Large page support 3267 3268 static size_t _large_page_size = 0; 3269 3270 size_t os::Linux::find_large_page_size() { 3271 size_t large_page_size = 0; 3272 3273 // large_page_size on Linux is used to round up heap size. x86 uses either 3274 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3275 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3276 // page as large as 256M. 3277 // 3278 // Here we try to figure out page size by parsing /proc/meminfo and looking 3279 // for a line with the following format: 3280 // Hugepagesize: 2048 kB 3281 // 3282 // If we can't determine the value (e.g. /proc is not mounted, or the text 3283 // format has been changed), we'll use the largest page size supported by 3284 // the processor. 3285 3286 #ifndef ZERO 3287 large_page_size = 3288 AARCH64_ONLY(2 * M) 3289 AMD64_ONLY(2 * M) 3290 ARM32_ONLY(2 * M) 3291 IA32_ONLY(4 * M) 3292 IA64_ONLY(256 * M) 3293 PPC_ONLY(4 * M) 3294 S390_ONLY(1 * M) 3295 SPARC_ONLY(4 * M); 3296 #endif // ZERO 3297 3298 FILE *fp = fopen("/proc/meminfo", "r"); 3299 if (fp) { 3300 while (!feof(fp)) { 3301 int x = 0; 3302 char buf[16]; 3303 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3304 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3305 large_page_size = x * K; 3306 break; 3307 } 3308 } else { 3309 // skip to next line 3310 for (;;) { 3311 int ch = fgetc(fp); 3312 if (ch == EOF || ch == (int)'\n') break; 3313 } 3314 } 3315 } 3316 fclose(fp); 3317 } 3318 3319 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3320 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3321 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3322 proper_unit_for_byte_size(large_page_size)); 3323 } 3324 3325 return large_page_size; 3326 } 3327 3328 size_t os::Linux::setup_large_page_size() { 3329 _large_page_size = Linux::find_large_page_size(); 3330 const size_t default_page_size = (size_t)Linux::page_size(); 3331 if (_large_page_size > default_page_size) { 3332 _page_sizes[0] = _large_page_size; 3333 _page_sizes[1] = default_page_size; 3334 _page_sizes[2] = 0; 3335 } 3336 3337 return _large_page_size; 3338 } 3339 3340 bool os::Linux::setup_large_page_type(size_t page_size) { 3341 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3342 FLAG_IS_DEFAULT(UseSHM) && 3343 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3344 3345 // The type of large pages has not been specified by the user. 3346 3347 // Try UseHugeTLBFS and then UseSHM. 3348 UseHugeTLBFS = UseSHM = true; 3349 3350 // Don't try UseTransparentHugePages since there are known 3351 // performance issues with it turned on. This might change in the future. 3352 UseTransparentHugePages = false; 3353 } 3354 3355 if (UseTransparentHugePages) { 3356 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3357 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3358 UseHugeTLBFS = false; 3359 UseSHM = false; 3360 return true; 3361 } 3362 UseTransparentHugePages = false; 3363 } 3364 3365 if (UseHugeTLBFS) { 3366 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3367 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3368 UseSHM = false; 3369 return true; 3370 } 3371 UseHugeTLBFS = false; 3372 } 3373 3374 return UseSHM; 3375 } 3376 3377 void os::large_page_init() { 3378 if (!UseLargePages && 3379 !UseTransparentHugePages && 3380 !UseHugeTLBFS && 3381 !UseSHM) { 3382 // Not using large pages. 3383 return; 3384 } 3385 3386 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3387 // The user explicitly turned off large pages. 3388 // Ignore the rest of the large pages flags. 3389 UseTransparentHugePages = false; 3390 UseHugeTLBFS = false; 3391 UseSHM = false; 3392 return; 3393 } 3394 3395 size_t large_page_size = Linux::setup_large_page_size(); 3396 UseLargePages = Linux::setup_large_page_type(large_page_size); 3397 3398 set_coredump_filter(); 3399 } 3400 3401 #ifndef SHM_HUGETLB 3402 #define SHM_HUGETLB 04000 3403 #endif 3404 3405 #define shm_warning_format(format, ...) \ 3406 do { \ 3407 if (UseLargePages && \ 3408 (!FLAG_IS_DEFAULT(UseLargePages) || \ 3409 !FLAG_IS_DEFAULT(UseSHM) || \ 3410 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \ 3411 warning(format, __VA_ARGS__); \ 3412 } \ 3413 } while (0) 3414 3415 #define shm_warning(str) shm_warning_format("%s", str) 3416 3417 #define shm_warning_with_errno(str) \ 3418 do { \ 3419 int err = errno; \ 3420 shm_warning_format(str " (error = %d)", err); \ 3421 } while (0) 3422 3423 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) { 3424 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment"); 3425 3426 if (!is_size_aligned(alignment, SHMLBA)) { 3427 assert(false, "Code below assumes that alignment is at least SHMLBA aligned"); 3428 return NULL; 3429 } 3430 3431 // To ensure that we get 'alignment' aligned memory from shmat, 3432 // we pre-reserve aligned virtual memory and then attach to that. 3433 3434 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL); 3435 if (pre_reserved_addr == NULL) { 3436 // Couldn't pre-reserve aligned memory. 3437 shm_warning("Failed to pre-reserve aligned memory for shmat."); 3438 return NULL; 3439 } 3440 3441 // SHM_REMAP is needed to allow shmat to map over an existing mapping. 3442 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP); 3443 3444 if ((intptr_t)addr == -1) { 3445 int err = errno; 3446 shm_warning_with_errno("Failed to attach shared memory."); 3447 3448 assert(err != EACCES, "Unexpected error"); 3449 assert(err != EIDRM, "Unexpected error"); 3450 assert(err != EINVAL, "Unexpected error"); 3451 3452 // Since we don't know if the kernel unmapped the pre-reserved memory area 3453 // we can't unmap it, since that would potentially unmap memory that was 3454 // mapped from other threads. 3455 return NULL; 3456 } 3457 3458 return addr; 3459 } 3460 3461 static char* shmat_at_address(int shmid, char* req_addr) { 3462 if (!is_ptr_aligned(req_addr, SHMLBA)) { 3463 assert(false, "Requested address needs to be SHMLBA aligned"); 3464 return NULL; 3465 } 3466 3467 char* addr = (char*)shmat(shmid, req_addr, 0); 3468 3469 if ((intptr_t)addr == -1) { 3470 shm_warning_with_errno("Failed to attach shared memory."); 3471 return NULL; 3472 } 3473 3474 return addr; 3475 } 3476 3477 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) { 3478 // If a req_addr has been provided, we assume that the caller has already aligned the address. 3479 if (req_addr != NULL) { 3480 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size"); 3481 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment"); 3482 return shmat_at_address(shmid, req_addr); 3483 } 3484 3485 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically 3486 // return large page size aligned memory addresses when req_addr == NULL. 3487 // However, if the alignment is larger than the large page size, we have 3488 // to manually ensure that the memory returned is 'alignment' aligned. 3489 if (alignment > os::large_page_size()) { 3490 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size"); 3491 return shmat_with_alignment(shmid, bytes, alignment); 3492 } else { 3493 return shmat_at_address(shmid, NULL); 3494 } 3495 } 3496 3497 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3498 char* req_addr, bool exec) { 3499 // "exec" is passed in but not used. Creating the shared image for 3500 // the code cache doesn't have an SHM_X executable permission to check. 3501 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3502 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3503 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address"); 3504 3505 if (!is_size_aligned(bytes, os::large_page_size())) { 3506 return NULL; // Fallback to small pages. 3507 } 3508 3509 // Create a large shared memory region to attach to based on size. 3510 // Currently, size is the total size of the heap. 3511 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3512 if (shmid == -1) { 3513 // Possible reasons for shmget failure: 3514 // 1. shmmax is too small for Java heap. 3515 // > check shmmax value: cat /proc/sys/kernel/shmmax 3516 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3517 // 2. not enough large page memory. 3518 // > check available large pages: cat /proc/meminfo 3519 // > increase amount of large pages: 3520 // echo new_value > /proc/sys/vm/nr_hugepages 3521 // Note 1: different Linux may use different name for this property, 3522 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3523 // Note 2: it's possible there's enough physical memory available but 3524 // they are so fragmented after a long run that they can't 3525 // coalesce into large pages. Try to reserve large pages when 3526 // the system is still "fresh". 3527 shm_warning_with_errno("Failed to reserve shared memory."); 3528 return NULL; 3529 } 3530 3531 // Attach to the region. 3532 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr); 3533 3534 // Remove shmid. If shmat() is successful, the actual shared memory segment 3535 // will be deleted when it's detached by shmdt() or when the process 3536 // terminates. If shmat() is not successful this will remove the shared 3537 // segment immediately. 3538 shmctl(shmid, IPC_RMID, NULL); 3539 3540 return addr; 3541 } 3542 3543 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3544 int error) { 3545 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3546 3547 bool warn_on_failure = UseLargePages && 3548 (!FLAG_IS_DEFAULT(UseLargePages) || 3549 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3550 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3551 3552 if (warn_on_failure) { 3553 char msg[128]; 3554 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3555 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3556 warning("%s", msg); 3557 } 3558 } 3559 3560 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3561 char* req_addr, 3562 bool exec) { 3563 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3564 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3565 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3566 3567 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3568 char* addr = (char*)::mmap(req_addr, bytes, prot, 3569 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3570 -1, 0); 3571 3572 if (addr == MAP_FAILED) { 3573 warn_on_large_pages_failure(req_addr, bytes, errno); 3574 return NULL; 3575 } 3576 3577 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3578 3579 return addr; 3580 } 3581 3582 // Reserve memory using mmap(MAP_HUGETLB). 3583 // - bytes shall be a multiple of alignment. 3584 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3585 // - alignment sets the alignment at which memory shall be allocated. 3586 // It must be a multiple of allocation granularity. 3587 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3588 // req_addr or NULL. 3589 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3590 size_t alignment, 3591 char* req_addr, 3592 bool exec) { 3593 size_t large_page_size = os::large_page_size(); 3594 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3595 3596 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3597 assert(is_size_aligned(bytes, alignment), "Must be"); 3598 3599 // First reserve - but not commit - the address range in small pages. 3600 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3601 3602 if (start == NULL) { 3603 return NULL; 3604 } 3605 3606 assert(is_ptr_aligned(start, alignment), "Must be"); 3607 3608 char* end = start + bytes; 3609 3610 // Find the regions of the allocated chunk that can be promoted to large pages. 3611 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3612 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3613 3614 size_t lp_bytes = lp_end - lp_start; 3615 3616 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3617 3618 if (lp_bytes == 0) { 3619 // The mapped region doesn't even span the start and the end of a large page. 3620 // Fall back to allocate a non-special area. 3621 ::munmap(start, end - start); 3622 return NULL; 3623 } 3624 3625 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3626 3627 void* result; 3628 3629 // Commit small-paged leading area. 3630 if (start != lp_start) { 3631 result = ::mmap(start, lp_start - start, prot, 3632 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3633 -1, 0); 3634 if (result == MAP_FAILED) { 3635 ::munmap(lp_start, end - lp_start); 3636 return NULL; 3637 } 3638 } 3639 3640 // Commit large-paged area. 3641 result = ::mmap(lp_start, lp_bytes, prot, 3642 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3643 -1, 0); 3644 if (result == MAP_FAILED) { 3645 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3646 // If the mmap above fails, the large pages region will be unmapped and we 3647 // have regions before and after with small pages. Release these regions. 3648 // 3649 // | mapped | unmapped | mapped | 3650 // ^ ^ ^ ^ 3651 // start lp_start lp_end end 3652 // 3653 ::munmap(start, lp_start - start); 3654 ::munmap(lp_end, end - lp_end); 3655 return NULL; 3656 } 3657 3658 // Commit small-paged trailing area. 3659 if (lp_end != end) { 3660 result = ::mmap(lp_end, end - lp_end, prot, 3661 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3662 -1, 0); 3663 if (result == MAP_FAILED) { 3664 ::munmap(start, lp_end - start); 3665 return NULL; 3666 } 3667 } 3668 3669 return start; 3670 } 3671 3672 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3673 size_t alignment, 3674 char* req_addr, 3675 bool exec) { 3676 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3677 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3678 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3679 assert(is_power_of_2(os::large_page_size()), "Must be"); 3680 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3681 3682 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3683 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3684 } else { 3685 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3686 } 3687 } 3688 3689 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3690 char* req_addr, bool exec) { 3691 assert(UseLargePages, "only for large pages"); 3692 3693 char* addr; 3694 if (UseSHM) { 3695 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3696 } else { 3697 assert(UseHugeTLBFS, "must be"); 3698 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3699 } 3700 3701 if (addr != NULL) { 3702 if (UseNUMAInterleaving) { 3703 numa_make_global(addr, bytes); 3704 } 3705 3706 // The memory is committed 3707 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3708 } 3709 3710 return addr; 3711 } 3712 3713 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3714 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3715 return shmdt(base) == 0; 3716 } 3717 3718 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3719 return pd_release_memory(base, bytes); 3720 } 3721 3722 bool os::release_memory_special(char* base, size_t bytes) { 3723 bool res; 3724 if (MemTracker::tracking_level() > NMT_minimal) { 3725 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3726 res = os::Linux::release_memory_special_impl(base, bytes); 3727 if (res) { 3728 tkr.record((address)base, bytes); 3729 } 3730 3731 } else { 3732 res = os::Linux::release_memory_special_impl(base, bytes); 3733 } 3734 return res; 3735 } 3736 3737 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3738 assert(UseLargePages, "only for large pages"); 3739 bool res; 3740 3741 if (UseSHM) { 3742 res = os::Linux::release_memory_special_shm(base, bytes); 3743 } else { 3744 assert(UseHugeTLBFS, "must be"); 3745 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3746 } 3747 return res; 3748 } 3749 3750 size_t os::large_page_size() { 3751 return _large_page_size; 3752 } 3753 3754 // With SysV SHM the entire memory region must be allocated as shared 3755 // memory. 3756 // HugeTLBFS allows application to commit large page memory on demand. 3757 // However, when committing memory with HugeTLBFS fails, the region 3758 // that was supposed to be committed will lose the old reservation 3759 // and allow other threads to steal that memory region. Because of this 3760 // behavior we can't commit HugeTLBFS memory. 3761 bool os::can_commit_large_page_memory() { 3762 return UseTransparentHugePages; 3763 } 3764 3765 bool os::can_execute_large_page_memory() { 3766 return UseTransparentHugePages || UseHugeTLBFS; 3767 } 3768 3769 // Reserve memory at an arbitrary address, only if that area is 3770 // available (and not reserved for something else). 3771 3772 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3773 const int max_tries = 10; 3774 char* base[max_tries]; 3775 size_t size[max_tries]; 3776 const size_t gap = 0x000000; 3777 3778 // Assert only that the size is a multiple of the page size, since 3779 // that's all that mmap requires, and since that's all we really know 3780 // about at this low abstraction level. If we need higher alignment, 3781 // we can either pass an alignment to this method or verify alignment 3782 // in one of the methods further up the call chain. See bug 5044738. 3783 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3784 3785 // Repeatedly allocate blocks until the block is allocated at the 3786 // right spot. 3787 3788 // Linux mmap allows caller to pass an address as hint; give it a try first, 3789 // if kernel honors the hint then we can return immediately. 3790 char * addr = anon_mmap(requested_addr, bytes, false); 3791 if (addr == requested_addr) { 3792 return requested_addr; 3793 } 3794 3795 if (addr != NULL) { 3796 // mmap() is successful but it fails to reserve at the requested address 3797 anon_munmap(addr, bytes); 3798 } 3799 3800 int i; 3801 for (i = 0; i < max_tries; ++i) { 3802 base[i] = reserve_memory(bytes); 3803 3804 if (base[i] != NULL) { 3805 // Is this the block we wanted? 3806 if (base[i] == requested_addr) { 3807 size[i] = bytes; 3808 break; 3809 } 3810 3811 // Does this overlap the block we wanted? Give back the overlapped 3812 // parts and try again. 3813 3814 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3815 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3816 unmap_memory(base[i], top_overlap); 3817 base[i] += top_overlap; 3818 size[i] = bytes - top_overlap; 3819 } else { 3820 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3821 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3822 unmap_memory(requested_addr, bottom_overlap); 3823 size[i] = bytes - bottom_overlap; 3824 } else { 3825 size[i] = bytes; 3826 } 3827 } 3828 } 3829 } 3830 3831 // Give back the unused reserved pieces. 3832 3833 for (int j = 0; j < i; ++j) { 3834 if (base[j] != NULL) { 3835 unmap_memory(base[j], size[j]); 3836 } 3837 } 3838 3839 if (i < max_tries) { 3840 return requested_addr; 3841 } else { 3842 return NULL; 3843 } 3844 } 3845 3846 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3847 return ::read(fd, buf, nBytes); 3848 } 3849 3850 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3851 return ::pread(fd, buf, nBytes, offset); 3852 } 3853 3854 // Short sleep, direct OS call. 3855 // 3856 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3857 // sched_yield(2) will actually give up the CPU: 3858 // 3859 // * Alone on this pariticular CPU, keeps running. 3860 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3861 // (pre 2.6.39). 3862 // 3863 // So calling this with 0 is an alternative. 3864 // 3865 void os::naked_short_sleep(jlong ms) { 3866 struct timespec req; 3867 3868 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3869 req.tv_sec = 0; 3870 if (ms > 0) { 3871 req.tv_nsec = (ms % 1000) * 1000000; 3872 } else { 3873 req.tv_nsec = 1; 3874 } 3875 3876 nanosleep(&req, NULL); 3877 3878 return; 3879 } 3880 3881 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3882 void os::infinite_sleep() { 3883 while (true) { // sleep forever ... 3884 ::sleep(100); // ... 100 seconds at a time 3885 } 3886 } 3887 3888 // Used to convert frequent JVM_Yield() to nops 3889 bool os::dont_yield() { 3890 return DontYieldALot; 3891 } 3892 3893 void os::naked_yield() { 3894 sched_yield(); 3895 } 3896 3897 //////////////////////////////////////////////////////////////////////////////// 3898 // thread priority support 3899 3900 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3901 // only supports dynamic priority, static priority must be zero. For real-time 3902 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3903 // However, for large multi-threaded applications, SCHED_RR is not only slower 3904 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3905 // of 5 runs - Sep 2005). 3906 // 3907 // The following code actually changes the niceness of kernel-thread/LWP. It 3908 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3909 // not the entire user process, and user level threads are 1:1 mapped to kernel 3910 // threads. It has always been the case, but could change in the future. For 3911 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3912 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3913 3914 int os::java_to_os_priority[CriticalPriority + 1] = { 3915 19, // 0 Entry should never be used 3916 3917 4, // 1 MinPriority 3918 3, // 2 3919 2, // 3 3920 3921 1, // 4 3922 0, // 5 NormPriority 3923 -1, // 6 3924 3925 -2, // 7 3926 -3, // 8 3927 -4, // 9 NearMaxPriority 3928 3929 -5, // 10 MaxPriority 3930 3931 -5 // 11 CriticalPriority 3932 }; 3933 3934 static int prio_init() { 3935 if (ThreadPriorityPolicy == 1) { 3936 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3937 // if effective uid is not root. Perhaps, a more elegant way of doing 3938 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3939 if (geteuid() != 0) { 3940 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3941 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3942 } 3943 ThreadPriorityPolicy = 0; 3944 } 3945 } 3946 if (UseCriticalJavaThreadPriority) { 3947 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3948 } 3949 return 0; 3950 } 3951 3952 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3953 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3954 3955 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3956 return (ret == 0) ? OS_OK : OS_ERR; 3957 } 3958 3959 OSReturn os::get_native_priority(const Thread* const thread, 3960 int *priority_ptr) { 3961 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3962 *priority_ptr = java_to_os_priority[NormPriority]; 3963 return OS_OK; 3964 } 3965 3966 errno = 0; 3967 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3968 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3969 } 3970 3971 // Hint to the underlying OS that a task switch would not be good. 3972 // Void return because it's a hint and can fail. 3973 void os::hint_no_preempt() {} 3974 3975 //////////////////////////////////////////////////////////////////////////////// 3976 // suspend/resume support 3977 3978 // the low-level signal-based suspend/resume support is a remnant from the 3979 // old VM-suspension that used to be for java-suspension, safepoints etc, 3980 // within hotspot. Now there is a single use-case for this: 3981 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3982 // that runs in the watcher thread. 3983 // The remaining code is greatly simplified from the more general suspension 3984 // code that used to be used. 3985 // 3986 // The protocol is quite simple: 3987 // - suspend: 3988 // - sends a signal to the target thread 3989 // - polls the suspend state of the osthread using a yield loop 3990 // - target thread signal handler (SR_handler) sets suspend state 3991 // and blocks in sigsuspend until continued 3992 // - resume: 3993 // - sets target osthread state to continue 3994 // - sends signal to end the sigsuspend loop in the SR_handler 3995 // 3996 // Note that the SR_lock plays no role in this suspend/resume protocol, 3997 // but is checked for NULL in SR_handler as a thread termination indicator. 3998 3999 static void resume_clear_context(OSThread *osthread) { 4000 osthread->set_ucontext(NULL); 4001 osthread->set_siginfo(NULL); 4002 } 4003 4004 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 4005 ucontext_t* context) { 4006 osthread->set_ucontext(context); 4007 osthread->set_siginfo(siginfo); 4008 } 4009 4010 // Handler function invoked when a thread's execution is suspended or 4011 // resumed. We have to be careful that only async-safe functions are 4012 // called here (Note: most pthread functions are not async safe and 4013 // should be avoided.) 4014 // 4015 // Note: sigwait() is a more natural fit than sigsuspend() from an 4016 // interface point of view, but sigwait() prevents the signal hander 4017 // from being run. libpthread would get very confused by not having 4018 // its signal handlers run and prevents sigwait()'s use with the 4019 // mutex granting granting signal. 4020 // 4021 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 4022 // 4023 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 4024 // Save and restore errno to avoid confusing native code with EINTR 4025 // after sigsuspend. 4026 int old_errno = errno; 4027 4028 Thread* thread = Thread::current_or_null_safe(); 4029 assert(thread != NULL, "Missing current thread in SR_handler"); 4030 4031 // On some systems we have seen signal delivery get "stuck" until the signal 4032 // mask is changed as part of thread termination. Check that the current thread 4033 // has not already terminated (via SR_lock()) - else the following assertion 4034 // will fail because the thread is no longer a JavaThread as the ~JavaThread 4035 // destructor has completed. 4036 4037 if (thread->SR_lock() == NULL) { 4038 return; 4039 } 4040 4041 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 4042 4043 OSThread* osthread = thread->osthread(); 4044 4045 os::SuspendResume::State current = osthread->sr.state(); 4046 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 4047 suspend_save_context(osthread, siginfo, context); 4048 4049 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 4050 os::SuspendResume::State state = osthread->sr.suspended(); 4051 if (state == os::SuspendResume::SR_SUSPENDED) { 4052 sigset_t suspend_set; // signals for sigsuspend() 4053 sigemptyset(&suspend_set); 4054 // get current set of blocked signals and unblock resume signal 4055 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 4056 sigdelset(&suspend_set, SR_signum); 4057 4058 sr_semaphore.signal(); 4059 // wait here until we are resumed 4060 while (1) { 4061 sigsuspend(&suspend_set); 4062 4063 os::SuspendResume::State result = osthread->sr.running(); 4064 if (result == os::SuspendResume::SR_RUNNING) { 4065 sr_semaphore.signal(); 4066 break; 4067 } 4068 } 4069 4070 } else if (state == os::SuspendResume::SR_RUNNING) { 4071 // request was cancelled, continue 4072 } else { 4073 ShouldNotReachHere(); 4074 } 4075 4076 resume_clear_context(osthread); 4077 } else if (current == os::SuspendResume::SR_RUNNING) { 4078 // request was cancelled, continue 4079 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 4080 // ignore 4081 } else { 4082 // ignore 4083 } 4084 4085 errno = old_errno; 4086 } 4087 4088 static int SR_initialize() { 4089 struct sigaction act; 4090 char *s; 4091 4092 // Get signal number to use for suspend/resume 4093 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 4094 int sig = ::strtol(s, 0, 10); 4095 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4096 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4097 SR_signum = sig; 4098 } else { 4099 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4100 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4101 } 4102 } 4103 4104 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4105 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4106 4107 sigemptyset(&SR_sigset); 4108 sigaddset(&SR_sigset, SR_signum); 4109 4110 // Set up signal handler for suspend/resume 4111 act.sa_flags = SA_RESTART|SA_SIGINFO; 4112 act.sa_handler = (void (*)(int)) SR_handler; 4113 4114 // SR_signum is blocked by default. 4115 // 4528190 - We also need to block pthread restart signal (32 on all 4116 // supported Linux platforms). Note that LinuxThreads need to block 4117 // this signal for all threads to work properly. So we don't have 4118 // to use hard-coded signal number when setting up the mask. 4119 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4120 4121 if (sigaction(SR_signum, &act, 0) == -1) { 4122 return -1; 4123 } 4124 4125 // Save signal flag 4126 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4127 return 0; 4128 } 4129 4130 static int sr_notify(OSThread* osthread) { 4131 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4132 assert_status(status == 0, status, "pthread_kill"); 4133 return status; 4134 } 4135 4136 // "Randomly" selected value for how long we want to spin 4137 // before bailing out on suspending a thread, also how often 4138 // we send a signal to a thread we want to resume 4139 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4140 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4141 4142 // returns true on success and false on error - really an error is fatal 4143 // but this seems the normal response to library errors 4144 static bool do_suspend(OSThread* osthread) { 4145 assert(osthread->sr.is_running(), "thread should be running"); 4146 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4147 4148 // mark as suspended and send signal 4149 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4150 // failed to switch, state wasn't running? 4151 ShouldNotReachHere(); 4152 return false; 4153 } 4154 4155 if (sr_notify(osthread) != 0) { 4156 ShouldNotReachHere(); 4157 } 4158 4159 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4160 while (true) { 4161 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4162 break; 4163 } else { 4164 // timeout 4165 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4166 if (cancelled == os::SuspendResume::SR_RUNNING) { 4167 return false; 4168 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4169 // make sure that we consume the signal on the semaphore as well 4170 sr_semaphore.wait(); 4171 break; 4172 } else { 4173 ShouldNotReachHere(); 4174 return false; 4175 } 4176 } 4177 } 4178 4179 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4180 return true; 4181 } 4182 4183 static void do_resume(OSThread* osthread) { 4184 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4185 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4186 4187 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4188 // failed to switch to WAKEUP_REQUEST 4189 ShouldNotReachHere(); 4190 return; 4191 } 4192 4193 while (true) { 4194 if (sr_notify(osthread) == 0) { 4195 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4196 if (osthread->sr.is_running()) { 4197 return; 4198 } 4199 } 4200 } else { 4201 ShouldNotReachHere(); 4202 } 4203 } 4204 4205 guarantee(osthread->sr.is_running(), "Must be running!"); 4206 } 4207 4208 /////////////////////////////////////////////////////////////////////////////////// 4209 // signal handling (except suspend/resume) 4210 4211 // This routine may be used by user applications as a "hook" to catch signals. 4212 // The user-defined signal handler must pass unrecognized signals to this 4213 // routine, and if it returns true (non-zero), then the signal handler must 4214 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4215 // routine will never retun false (zero), but instead will execute a VM panic 4216 // routine kill the process. 4217 // 4218 // If this routine returns false, it is OK to call it again. This allows 4219 // the user-defined signal handler to perform checks either before or after 4220 // the VM performs its own checks. Naturally, the user code would be making 4221 // a serious error if it tried to handle an exception (such as a null check 4222 // or breakpoint) that the VM was generating for its own correct operation. 4223 // 4224 // This routine may recognize any of the following kinds of signals: 4225 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4226 // It should be consulted by handlers for any of those signals. 4227 // 4228 // The caller of this routine must pass in the three arguments supplied 4229 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4230 // field of the structure passed to sigaction(). This routine assumes that 4231 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4232 // 4233 // Note that the VM will print warnings if it detects conflicting signal 4234 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4235 // 4236 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4237 siginfo_t* siginfo, 4238 void* ucontext, 4239 int abort_if_unrecognized); 4240 4241 void signalHandler(int sig, siginfo_t* info, void* uc) { 4242 assert(info != NULL && uc != NULL, "it must be old kernel"); 4243 int orig_errno = errno; // Preserve errno value over signal handler. 4244 JVM_handle_linux_signal(sig, info, uc, true); 4245 errno = orig_errno; 4246 } 4247 4248 4249 // This boolean allows users to forward their own non-matching signals 4250 // to JVM_handle_linux_signal, harmlessly. 4251 bool os::Linux::signal_handlers_are_installed = false; 4252 4253 // For signal-chaining 4254 struct sigaction sigact[NSIG]; 4255 uint64_t sigs = 0; 4256 #if (64 < NSIG-1) 4257 #error "Not all signals can be encoded in sigs. Adapt its type!" 4258 #endif 4259 bool os::Linux::libjsig_is_loaded = false; 4260 typedef struct sigaction *(*get_signal_t)(int); 4261 get_signal_t os::Linux::get_signal_action = NULL; 4262 4263 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4264 struct sigaction *actp = NULL; 4265 4266 if (libjsig_is_loaded) { 4267 // Retrieve the old signal handler from libjsig 4268 actp = (*get_signal_action)(sig); 4269 } 4270 if (actp == NULL) { 4271 // Retrieve the preinstalled signal handler from jvm 4272 actp = get_preinstalled_handler(sig); 4273 } 4274 4275 return actp; 4276 } 4277 4278 static bool call_chained_handler(struct sigaction *actp, int sig, 4279 siginfo_t *siginfo, void *context) { 4280 // Call the old signal handler 4281 if (actp->sa_handler == SIG_DFL) { 4282 // It's more reasonable to let jvm treat it as an unexpected exception 4283 // instead of taking the default action. 4284 return false; 4285 } else if (actp->sa_handler != SIG_IGN) { 4286 if ((actp->sa_flags & SA_NODEFER) == 0) { 4287 // automaticlly block the signal 4288 sigaddset(&(actp->sa_mask), sig); 4289 } 4290 4291 sa_handler_t hand = NULL; 4292 sa_sigaction_t sa = NULL; 4293 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4294 // retrieve the chained handler 4295 if (siginfo_flag_set) { 4296 sa = actp->sa_sigaction; 4297 } else { 4298 hand = actp->sa_handler; 4299 } 4300 4301 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4302 actp->sa_handler = SIG_DFL; 4303 } 4304 4305 // try to honor the signal mask 4306 sigset_t oset; 4307 sigemptyset(&oset); 4308 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4309 4310 // call into the chained handler 4311 if (siginfo_flag_set) { 4312 (*sa)(sig, siginfo, context); 4313 } else { 4314 (*hand)(sig); 4315 } 4316 4317 // restore the signal mask 4318 pthread_sigmask(SIG_SETMASK, &oset, NULL); 4319 } 4320 // Tell jvm's signal handler the signal is taken care of. 4321 return true; 4322 } 4323 4324 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4325 bool chained = false; 4326 // signal-chaining 4327 if (UseSignalChaining) { 4328 struct sigaction *actp = get_chained_signal_action(sig); 4329 if (actp != NULL) { 4330 chained = call_chained_handler(actp, sig, siginfo, context); 4331 } 4332 } 4333 return chained; 4334 } 4335 4336 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4337 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4338 return &sigact[sig]; 4339 } 4340 return NULL; 4341 } 4342 4343 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4344 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4345 sigact[sig] = oldAct; 4346 sigs |= (uint64_t)1 << (sig-1); 4347 } 4348 4349 // for diagnostic 4350 int sigflags[NSIG]; 4351 4352 int os::Linux::get_our_sigflags(int sig) { 4353 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4354 return sigflags[sig]; 4355 } 4356 4357 void os::Linux::set_our_sigflags(int sig, int flags) { 4358 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4359 if (sig > 0 && sig < NSIG) { 4360 sigflags[sig] = flags; 4361 } 4362 } 4363 4364 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4365 // Check for overwrite. 4366 struct sigaction oldAct; 4367 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4368 4369 void* oldhand = oldAct.sa_sigaction 4370 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4371 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4372 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4373 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4374 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4375 if (AllowUserSignalHandlers || !set_installed) { 4376 // Do not overwrite; user takes responsibility to forward to us. 4377 return; 4378 } else if (UseSignalChaining) { 4379 // save the old handler in jvm 4380 save_preinstalled_handler(sig, oldAct); 4381 // libjsig also interposes the sigaction() call below and saves the 4382 // old sigaction on it own. 4383 } else { 4384 fatal("Encountered unexpected pre-existing sigaction handler " 4385 "%#lx for signal %d.", (long)oldhand, sig); 4386 } 4387 } 4388 4389 struct sigaction sigAct; 4390 sigfillset(&(sigAct.sa_mask)); 4391 sigAct.sa_handler = SIG_DFL; 4392 if (!set_installed) { 4393 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4394 } else { 4395 sigAct.sa_sigaction = signalHandler; 4396 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4397 } 4398 // Save flags, which are set by ours 4399 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4400 sigflags[sig] = sigAct.sa_flags; 4401 4402 int ret = sigaction(sig, &sigAct, &oldAct); 4403 assert(ret == 0, "check"); 4404 4405 void* oldhand2 = oldAct.sa_sigaction 4406 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4407 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4408 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4409 } 4410 4411 // install signal handlers for signals that HotSpot needs to 4412 // handle in order to support Java-level exception handling. 4413 4414 void os::Linux::install_signal_handlers() { 4415 if (!signal_handlers_are_installed) { 4416 signal_handlers_are_installed = true; 4417 4418 // signal-chaining 4419 typedef void (*signal_setting_t)(); 4420 signal_setting_t begin_signal_setting = NULL; 4421 signal_setting_t end_signal_setting = NULL; 4422 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4423 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4424 if (begin_signal_setting != NULL) { 4425 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4426 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4427 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4428 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4429 libjsig_is_loaded = true; 4430 assert(UseSignalChaining, "should enable signal-chaining"); 4431 } 4432 if (libjsig_is_loaded) { 4433 // Tell libjsig jvm is setting signal handlers 4434 (*begin_signal_setting)(); 4435 } 4436 4437 set_signal_handler(SIGSEGV, true); 4438 set_signal_handler(SIGPIPE, true); 4439 set_signal_handler(SIGBUS, true); 4440 set_signal_handler(SIGILL, true); 4441 set_signal_handler(SIGFPE, true); 4442 #if defined(PPC64) 4443 set_signal_handler(SIGTRAP, true); 4444 #endif 4445 set_signal_handler(SIGXFSZ, true); 4446 4447 if (libjsig_is_loaded) { 4448 // Tell libjsig jvm finishes setting signal handlers 4449 (*end_signal_setting)(); 4450 } 4451 4452 // We don't activate signal checker if libjsig is in place, we trust ourselves 4453 // and if UserSignalHandler is installed all bets are off. 4454 // Log that signal checking is off only if -verbose:jni is specified. 4455 if (CheckJNICalls) { 4456 if (libjsig_is_loaded) { 4457 if (PrintJNIResolving) { 4458 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4459 } 4460 check_signals = false; 4461 } 4462 if (AllowUserSignalHandlers) { 4463 if (PrintJNIResolving) { 4464 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4465 } 4466 check_signals = false; 4467 } 4468 } 4469 } 4470 } 4471 4472 // This is the fastest way to get thread cpu time on Linux. 4473 // Returns cpu time (user+sys) for any thread, not only for current. 4474 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4475 // It might work on 2.6.10+ with a special kernel/glibc patch. 4476 // For reference, please, see IEEE Std 1003.1-2004: 4477 // http://www.unix.org/single_unix_specification 4478 4479 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4480 struct timespec tp; 4481 int rc = os::Linux::clock_gettime(clockid, &tp); 4482 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4483 4484 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4485 } 4486 4487 void os::Linux::initialize_os_info() { 4488 assert(_os_version == 0, "OS info already initialized"); 4489 4490 struct utsname _uname; 4491 4492 uint32_t major; 4493 uint32_t minor; 4494 uint32_t fix; 4495 4496 int rc; 4497 4498 // Kernel version is unknown if 4499 // verification below fails. 4500 _os_version = 0x01000000; 4501 4502 rc = uname(&_uname); 4503 if (rc != -1) { 4504 4505 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix); 4506 if (rc == 3) { 4507 4508 if (major < 256 && minor < 256 && fix < 256) { 4509 // Kernel version format is as expected, 4510 // set it overriding unknown state. 4511 _os_version = (major << 16) | 4512 (minor << 8 ) | 4513 (fix << 0 ) ; 4514 } 4515 } 4516 } 4517 } 4518 4519 uint32_t os::Linux::os_version() { 4520 assert(_os_version != 0, "not initialized"); 4521 return _os_version & 0x00FFFFFF; 4522 } 4523 4524 bool os::Linux::os_version_is_known() { 4525 assert(_os_version != 0, "not initialized"); 4526 return _os_version & 0x01000000 ? false : true; 4527 } 4528 4529 ///// 4530 // glibc on Linux platform uses non-documented flag 4531 // to indicate, that some special sort of signal 4532 // trampoline is used. 4533 // We will never set this flag, and we should 4534 // ignore this flag in our diagnostic 4535 #ifdef SIGNIFICANT_SIGNAL_MASK 4536 #undef SIGNIFICANT_SIGNAL_MASK 4537 #endif 4538 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4539 4540 static const char* get_signal_handler_name(address handler, 4541 char* buf, int buflen) { 4542 int offset = 0; 4543 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4544 if (found) { 4545 // skip directory names 4546 const char *p1, *p2; 4547 p1 = buf; 4548 size_t len = strlen(os::file_separator()); 4549 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4550 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4551 } else { 4552 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4553 } 4554 return buf; 4555 } 4556 4557 static void print_signal_handler(outputStream* st, int sig, 4558 char* buf, size_t buflen) { 4559 struct sigaction sa; 4560 4561 sigaction(sig, NULL, &sa); 4562 4563 // See comment for SIGNIFICANT_SIGNAL_MASK define 4564 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4565 4566 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4567 4568 address handler = (sa.sa_flags & SA_SIGINFO) 4569 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4570 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4571 4572 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4573 st->print("SIG_DFL"); 4574 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4575 st->print("SIG_IGN"); 4576 } else { 4577 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4578 } 4579 4580 st->print(", sa_mask[0]="); 4581 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4582 4583 address rh = VMError::get_resetted_sighandler(sig); 4584 // May be, handler was resetted by VMError? 4585 if (rh != NULL) { 4586 handler = rh; 4587 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4588 } 4589 4590 st->print(", sa_flags="); 4591 os::Posix::print_sa_flags(st, sa.sa_flags); 4592 4593 // Check: is it our handler? 4594 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4595 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4596 // It is our signal handler 4597 // check for flags, reset system-used one! 4598 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4599 st->print( 4600 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4601 os::Linux::get_our_sigflags(sig)); 4602 } 4603 } 4604 st->cr(); 4605 } 4606 4607 4608 #define DO_SIGNAL_CHECK(sig) \ 4609 do { \ 4610 if (!sigismember(&check_signal_done, sig)) { \ 4611 os::Linux::check_signal_handler(sig); \ 4612 } \ 4613 } while (0) 4614 4615 // This method is a periodic task to check for misbehaving JNI applications 4616 // under CheckJNI, we can add any periodic checks here 4617 4618 void os::run_periodic_checks() { 4619 if (check_signals == false) return; 4620 4621 // SEGV and BUS if overridden could potentially prevent 4622 // generation of hs*.log in the event of a crash, debugging 4623 // such a case can be very challenging, so we absolutely 4624 // check the following for a good measure: 4625 DO_SIGNAL_CHECK(SIGSEGV); 4626 DO_SIGNAL_CHECK(SIGILL); 4627 DO_SIGNAL_CHECK(SIGFPE); 4628 DO_SIGNAL_CHECK(SIGBUS); 4629 DO_SIGNAL_CHECK(SIGPIPE); 4630 DO_SIGNAL_CHECK(SIGXFSZ); 4631 #if defined(PPC64) 4632 DO_SIGNAL_CHECK(SIGTRAP); 4633 #endif 4634 4635 // ReduceSignalUsage allows the user to override these handlers 4636 // see comments at the very top and jvm_solaris.h 4637 if (!ReduceSignalUsage) { 4638 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4639 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4640 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4641 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4642 } 4643 4644 DO_SIGNAL_CHECK(SR_signum); 4645 } 4646 4647 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4648 4649 static os_sigaction_t os_sigaction = NULL; 4650 4651 void os::Linux::check_signal_handler(int sig) { 4652 char buf[O_BUFLEN]; 4653 address jvmHandler = NULL; 4654 4655 4656 struct sigaction act; 4657 if (os_sigaction == NULL) { 4658 // only trust the default sigaction, in case it has been interposed 4659 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4660 if (os_sigaction == NULL) return; 4661 } 4662 4663 os_sigaction(sig, (struct sigaction*)NULL, &act); 4664 4665 4666 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4667 4668 address thisHandler = (act.sa_flags & SA_SIGINFO) 4669 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4670 : CAST_FROM_FN_PTR(address, act.sa_handler); 4671 4672 4673 switch (sig) { 4674 case SIGSEGV: 4675 case SIGBUS: 4676 case SIGFPE: 4677 case SIGPIPE: 4678 case SIGILL: 4679 case SIGXFSZ: 4680 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4681 break; 4682 4683 case SHUTDOWN1_SIGNAL: 4684 case SHUTDOWN2_SIGNAL: 4685 case SHUTDOWN3_SIGNAL: 4686 case BREAK_SIGNAL: 4687 jvmHandler = (address)user_handler(); 4688 break; 4689 4690 default: 4691 if (sig == SR_signum) { 4692 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4693 } else { 4694 return; 4695 } 4696 break; 4697 } 4698 4699 if (thisHandler != jvmHandler) { 4700 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4701 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4702 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4703 // No need to check this sig any longer 4704 sigaddset(&check_signal_done, sig); 4705 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4706 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4707 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4708 exception_name(sig, buf, O_BUFLEN)); 4709 } 4710 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4711 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4712 tty->print("expected:"); 4713 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig)); 4714 tty->cr(); 4715 tty->print(" found:"); 4716 os::Posix::print_sa_flags(tty, act.sa_flags); 4717 tty->cr(); 4718 // No need to check this sig any longer 4719 sigaddset(&check_signal_done, sig); 4720 } 4721 4722 // Dump all the signal 4723 if (sigismember(&check_signal_done, sig)) { 4724 print_signal_handlers(tty, buf, O_BUFLEN); 4725 } 4726 } 4727 4728 extern void report_error(char* file_name, int line_no, char* title, 4729 char* format, ...); 4730 4731 // Some linux distributions (notably: Alpine Linux) include the 4732 // grsecurity in the kernel by default. Of particular interest from a 4733 // JVM perspective is PaX (https://pax.grsecurity.net/), which adds 4734 // some security features related to page attributes. Specifically, 4735 // the MPROTECT PaX functionality 4736 // (https://pax.grsecurity.net/docs/mprotect.txt) prevents dynamic 4737 // code generation by disallowing a (previously) writable page to be 4738 // marked as executable. This is, of course, exactly what HotSpot does 4739 // for both JIT compiled method, as well as for stubs, adapters, etc. 4740 // 4741 // Instead of crashing "lazily" when trying to make a page executable, 4742 // this code probes for the presence of PaX and reports the failure 4743 // eagerly. 4744 static void check_pax(void) { 4745 // Zero doesn't generate code dynamically, so no need to perform the PaX check 4746 #ifndef ZERO 4747 size_t size = os::Linux::page_size(); 4748 4749 void* p = ::mmap(NULL, size, PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4750 if (p == MAP_FAILED) { 4751 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "failed to allocate memory for PaX check."); 4752 } 4753 4754 int res = ::mprotect(p, size, PROT_WRITE|PROT_EXEC); 4755 if (res == -1) { 4756 vm_exit_during_initialization("Failed to mark memory page as executable", 4757 "Please check if grsecurity/PaX is enabled in your kernel.\n" 4758 "\n" 4759 "For example, you can do this by running (note: you may need root privileges):\n" 4760 "\n" 4761 " sysctl kernel.pax.softmode\n" 4762 "\n" 4763 "If PaX is included in the kernel you will see something like this:\n" 4764 "\n" 4765 " kernel.pax.softmode = 0\n" 4766 "\n" 4767 "In particular, if the value is 0 (zero), then PaX is enabled.\n" 4768 "\n" 4769 "PaX includes security functionality which interferes with the dynamic code\n" 4770 "generation the JVM relies on. Specifically, the MPROTECT functionality as\n" 4771 "described on https://pax.grsecurity.net/docs/mprotect.txt is not compatible\n" 4772 "with the JVM. If you want to allow the JVM to run you will have to disable PaX.\n" 4773 "You can do this on a per-executable basis using the paxctl tool.\n"); 4774 4775 } 4776 4777 ::munmap(p, size); 4778 #endif 4779 } 4780 4781 // this is called _before_ the most of global arguments have been parsed 4782 void os::init(void) { 4783 char dummy; // used to get a guess on initial stack address 4784 // first_hrtime = gethrtime(); 4785 4786 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4787 4788 init_random(1234567); 4789 4790 ThreadCritical::initialize(); 4791 4792 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4793 if (Linux::page_size() == -1) { 4794 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4795 os::strerror(errno)); 4796 } 4797 init_page_sizes((size_t) Linux::page_size()); 4798 4799 Linux::initialize_system_info(); 4800 4801 Linux::initialize_os_info(); 4802 4803 // main_thread points to the aboriginal thread 4804 Linux::_main_thread = pthread_self(); 4805 4806 Linux::clock_init(); 4807 initial_time_count = javaTimeNanos(); 4808 4809 // pthread_condattr initialization for monotonic clock 4810 int status; 4811 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4812 if ((status = pthread_condattr_init(_condattr)) != 0) { 4813 fatal("pthread_condattr_init: %s", os::strerror(status)); 4814 } 4815 // Only set the clock if CLOCK_MONOTONIC is available 4816 if (os::supports_monotonic_clock()) { 4817 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4818 if (status == EINVAL) { 4819 warning("Unable to use monotonic clock with relative timed-waits" \ 4820 " - changes to the time-of-day clock may have adverse affects"); 4821 } else { 4822 fatal("pthread_condattr_setclock: %s", os::strerror(status)); 4823 } 4824 } 4825 } 4826 // else it defaults to CLOCK_REALTIME 4827 4828 // retrieve entry point for pthread_setname_np 4829 Linux::_pthread_setname_np = 4830 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4831 4832 check_pax(); 4833 } 4834 4835 // To install functions for atexit system call 4836 extern "C" { 4837 static void perfMemory_exit_helper() { 4838 perfMemory_exit(); 4839 } 4840 } 4841 4842 // this is called _after_ the global arguments have been parsed 4843 jint os::init_2(void) { 4844 Linux::fast_thread_clock_init(); 4845 4846 // Allocate a single page and mark it as readable for safepoint polling 4847 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4848 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4849 4850 os::set_polling_page(polling_page); 4851 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page)); 4852 4853 if (!UseMembar) { 4854 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4855 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4856 os::set_memory_serialize_page(mem_serialize_page); 4857 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page)); 4858 } 4859 4860 // initialize suspend/resume support - must do this before signal_sets_init() 4861 if (SR_initialize() != 0) { 4862 perror("SR_initialize failed"); 4863 return JNI_ERR; 4864 } 4865 4866 Linux::signal_sets_init(); 4867 Linux::install_signal_handlers(); 4868 4869 // Check and sets minimum stack sizes against command line options 4870 if (Posix::set_minimum_stack_sizes() == JNI_ERR) { 4871 return JNI_ERR; 4872 } 4873 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4874 4875 #if defined(IA32) 4876 workaround_expand_exec_shield_cs_limit(); 4877 #endif 4878 4879 Linux::libpthread_init(); 4880 log_info(os)("HotSpot is running with %s, %s", 4881 Linux::glibc_version(), Linux::libpthread_version()); 4882 4883 if (UseNUMA) { 4884 if (!Linux::libnuma_init()) { 4885 UseNUMA = false; 4886 } else { 4887 if ((Linux::numa_max_node() < 1)) { 4888 // There's only one node(they start from 0), disable NUMA. 4889 UseNUMA = false; 4890 } 4891 } 4892 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4893 // we can make the adaptive lgrp chunk resizing work. If the user specified 4894 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4895 // disable adaptive resizing. 4896 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4897 if (FLAG_IS_DEFAULT(UseNUMA)) { 4898 UseNUMA = false; 4899 } else { 4900 if (FLAG_IS_DEFAULT(UseLargePages) && 4901 FLAG_IS_DEFAULT(UseSHM) && 4902 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4903 UseLargePages = false; 4904 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4905 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4906 UseAdaptiveSizePolicy = false; 4907 UseAdaptiveNUMAChunkSizing = false; 4908 } 4909 } 4910 } 4911 if (!UseNUMA && ForceNUMA) { 4912 UseNUMA = true; 4913 } 4914 } 4915 4916 if (MaxFDLimit) { 4917 // set the number of file descriptors to max. print out error 4918 // if getrlimit/setrlimit fails but continue regardless. 4919 struct rlimit nbr_files; 4920 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4921 if (status != 0) { 4922 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno)); 4923 } else { 4924 nbr_files.rlim_cur = nbr_files.rlim_max; 4925 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4926 if (status != 0) { 4927 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno)); 4928 } 4929 } 4930 } 4931 4932 // Initialize lock used to serialize thread creation (see os::create_thread) 4933 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4934 4935 // at-exit methods are called in the reverse order of their registration. 4936 // atexit functions are called on return from main or as a result of a 4937 // call to exit(3C). There can be only 32 of these functions registered 4938 // and atexit() does not set errno. 4939 4940 if (PerfAllowAtExitRegistration) { 4941 // only register atexit functions if PerfAllowAtExitRegistration is set. 4942 // atexit functions can be delayed until process exit time, which 4943 // can be problematic for embedded VM situations. Embedded VMs should 4944 // call DestroyJavaVM() to assure that VM resources are released. 4945 4946 // note: perfMemory_exit_helper atexit function may be removed in 4947 // the future if the appropriate cleanup code can be added to the 4948 // VM_Exit VMOperation's doit method. 4949 if (atexit(perfMemory_exit_helper) != 0) { 4950 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4951 } 4952 } 4953 4954 // initialize thread priority policy 4955 prio_init(); 4956 4957 return JNI_OK; 4958 } 4959 4960 // Mark the polling page as unreadable 4961 void os::make_polling_page_unreadable(void) { 4962 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4963 fatal("Could not disable polling page"); 4964 } 4965 } 4966 4967 // Mark the polling page as readable 4968 void os::make_polling_page_readable(void) { 4969 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4970 fatal("Could not enable polling page"); 4971 } 4972 } 4973 4974 // older glibc versions don't have this macro (which expands to 4975 // an optimized bit-counting function) so we have to roll our own 4976 #ifndef CPU_COUNT 4977 4978 static int _cpu_count(const cpu_set_t* cpus) { 4979 int count = 0; 4980 // only look up to the number of configured processors 4981 for (int i = 0; i < os::processor_count(); i++) { 4982 if (CPU_ISSET(i, cpus)) { 4983 count++; 4984 } 4985 } 4986 return count; 4987 } 4988 4989 #define CPU_COUNT(cpus) _cpu_count(cpus) 4990 4991 #endif // CPU_COUNT 4992 4993 // Get the current number of available processors for this process. 4994 // This value can change at any time during a process's lifetime. 4995 // sched_getaffinity gives an accurate answer as it accounts for cpusets. 4996 // If it appears there may be more than 1024 processors then we do a 4997 // dynamic check - see 6515172 for details. 4998 // If anything goes wrong we fallback to returning the number of online 4999 // processors - which can be greater than the number available to the process. 5000 int os::active_processor_count() { 5001 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors 5002 cpu_set_t* cpus_p = &cpus; 5003 int cpus_size = sizeof(cpu_set_t); 5004 5005 int configured_cpus = processor_count(); // upper bound on available cpus 5006 int cpu_count = 0; 5007 5008 // old build platforms may not support dynamic cpu sets 5009 #ifdef CPU_ALLOC 5010 5011 // To enable easy testing of the dynamic path on different platforms we 5012 // introduce a diagnostic flag: UseCpuAllocPath 5013 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) { 5014 // kernel may use a mask bigger than cpu_set_t 5015 log_trace(os)("active_processor_count: using dynamic path %s" 5016 "- configured processors: %d", 5017 UseCpuAllocPath ? "(forced) " : "", 5018 configured_cpus); 5019 cpus_p = CPU_ALLOC(configured_cpus); 5020 if (cpus_p != NULL) { 5021 cpus_size = CPU_ALLOC_SIZE(configured_cpus); 5022 // zero it just to be safe 5023 CPU_ZERO_S(cpus_size, cpus_p); 5024 } 5025 else { 5026 // failed to allocate so fallback to online cpus 5027 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 5028 log_trace(os)("active_processor_count: " 5029 "CPU_ALLOC failed (%s) - using " 5030 "online processor count: %d", 5031 os::strerror(errno), online_cpus); 5032 return online_cpus; 5033 } 5034 } 5035 else { 5036 log_trace(os)("active_processor_count: using static path - configured processors: %d", 5037 configured_cpus); 5038 } 5039 #else // CPU_ALLOC 5040 // these stubs won't be executed 5041 #define CPU_COUNT_S(size, cpus) -1 5042 #define CPU_FREE(cpus) 5043 5044 log_trace(os)("active_processor_count: only static path available - configured processors: %d", 5045 configured_cpus); 5046 #endif // CPU_ALLOC 5047 5048 // pid 0 means the current thread - which we have to assume represents the process 5049 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) { 5050 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5051 cpu_count = CPU_COUNT_S(cpus_size, cpus_p); 5052 } 5053 else { 5054 cpu_count = CPU_COUNT(cpus_p); 5055 } 5056 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count); 5057 } 5058 else { 5059 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN); 5060 warning("sched_getaffinity failed (%s)- using online processor count (%d) " 5061 "which may exceed available processors", os::strerror(errno), cpu_count); 5062 } 5063 5064 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used 5065 CPU_FREE(cpus_p); 5066 } 5067 5068 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check"); 5069 return cpu_count; 5070 } 5071 5072 void os::set_native_thread_name(const char *name) { 5073 if (Linux::_pthread_setname_np) { 5074 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 5075 snprintf(buf, sizeof(buf), "%s", name); 5076 buf[sizeof(buf) - 1] = '\0'; 5077 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 5078 // ERANGE should not happen; all other errors should just be ignored. 5079 assert(rc != ERANGE, "pthread_setname_np failed"); 5080 } 5081 } 5082 5083 bool os::distribute_processes(uint length, uint* distribution) { 5084 // Not yet implemented. 5085 return false; 5086 } 5087 5088 bool os::bind_to_processor(uint processor_id) { 5089 // Not yet implemented. 5090 return false; 5091 } 5092 5093 /// 5094 5095 void os::SuspendedThreadTask::internal_do_task() { 5096 if (do_suspend(_thread->osthread())) { 5097 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 5098 do_task(context); 5099 do_resume(_thread->osthread()); 5100 } 5101 } 5102 5103 class PcFetcher : public os::SuspendedThreadTask { 5104 public: 5105 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 5106 ExtendedPC result(); 5107 protected: 5108 void do_task(const os::SuspendedThreadTaskContext& context); 5109 private: 5110 ExtendedPC _epc; 5111 }; 5112 5113 ExtendedPC PcFetcher::result() { 5114 guarantee(is_done(), "task is not done yet."); 5115 return _epc; 5116 } 5117 5118 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 5119 Thread* thread = context.thread(); 5120 OSThread* osthread = thread->osthread(); 5121 if (osthread->ucontext() != NULL) { 5122 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext()); 5123 } else { 5124 // NULL context is unexpected, double-check this is the VMThread 5125 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 5126 } 5127 } 5128 5129 // Suspends the target using the signal mechanism and then grabs the PC before 5130 // resuming the target. Used by the flat-profiler only 5131 ExtendedPC os::get_thread_pc(Thread* thread) { 5132 // Make sure that it is called by the watcher for the VMThread 5133 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 5134 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 5135 5136 PcFetcher fetcher(thread); 5137 fetcher.run(); 5138 return fetcher.result(); 5139 } 5140 5141 //////////////////////////////////////////////////////////////////////////////// 5142 // debug support 5143 5144 bool os::find(address addr, outputStream* st) { 5145 Dl_info dlinfo; 5146 memset(&dlinfo, 0, sizeof(dlinfo)); 5147 if (dladdr(addr, &dlinfo) != 0) { 5148 st->print(PTR_FORMAT ": ", p2i(addr)); 5149 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 5150 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 5151 p2i(addr) - p2i(dlinfo.dli_saddr)); 5152 } else if (dlinfo.dli_fbase != NULL) { 5153 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 5154 } else { 5155 st->print("<absolute address>"); 5156 } 5157 if (dlinfo.dli_fname != NULL) { 5158 st->print(" in %s", dlinfo.dli_fname); 5159 } 5160 if (dlinfo.dli_fbase != NULL) { 5161 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 5162 } 5163 st->cr(); 5164 5165 if (Verbose) { 5166 // decode some bytes around the PC 5167 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 5168 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 5169 address lowest = (address) dlinfo.dli_sname; 5170 if (!lowest) lowest = (address) dlinfo.dli_fbase; 5171 if (begin < lowest) begin = lowest; 5172 Dl_info dlinfo2; 5173 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 5174 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 5175 end = (address) dlinfo2.dli_saddr; 5176 } 5177 Disassembler::decode(begin, end, st); 5178 } 5179 return true; 5180 } 5181 return false; 5182 } 5183 5184 //////////////////////////////////////////////////////////////////////////////// 5185 // misc 5186 5187 // This does not do anything on Linux. This is basically a hook for being 5188 // able to use structured exception handling (thread-local exception filters) 5189 // on, e.g., Win32. 5190 void 5191 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 5192 JavaCallArguments* args, Thread* thread) { 5193 f(value, method, args, thread); 5194 } 5195 5196 void os::print_statistics() { 5197 } 5198 5199 bool os::message_box(const char* title, const char* message) { 5200 int i; 5201 fdStream err(defaultStream::error_fd()); 5202 for (i = 0; i < 78; i++) err.print_raw("="); 5203 err.cr(); 5204 err.print_raw_cr(title); 5205 for (i = 0; i < 78; i++) err.print_raw("-"); 5206 err.cr(); 5207 err.print_raw_cr(message); 5208 for (i = 0; i < 78; i++) err.print_raw("="); 5209 err.cr(); 5210 5211 char buf[16]; 5212 // Prevent process from exiting upon "read error" without consuming all CPU 5213 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 5214 5215 return buf[0] == 'y' || buf[0] == 'Y'; 5216 } 5217 5218 int os::stat(const char *path, struct stat *sbuf) { 5219 char pathbuf[MAX_PATH]; 5220 if (strlen(path) > MAX_PATH - 1) { 5221 errno = ENAMETOOLONG; 5222 return -1; 5223 } 5224 os::native_path(strcpy(pathbuf, path)); 5225 return ::stat(pathbuf, sbuf); 5226 } 5227 5228 // Is a (classpath) directory empty? 5229 bool os::dir_is_empty(const char* path) { 5230 DIR *dir = NULL; 5231 struct dirent *ptr; 5232 5233 dir = opendir(path); 5234 if (dir == NULL) return true; 5235 5236 // Scan the directory 5237 bool result = true; 5238 char buf[sizeof(struct dirent) + MAX_PATH]; 5239 while (result && (ptr = ::readdir(dir)) != NULL) { 5240 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5241 result = false; 5242 } 5243 } 5244 closedir(dir); 5245 return result; 5246 } 5247 5248 // This code originates from JDK's sysOpen and open64_w 5249 // from src/solaris/hpi/src/system_md.c 5250 5251 int os::open(const char *path, int oflag, int mode) { 5252 if (strlen(path) > MAX_PATH - 1) { 5253 errno = ENAMETOOLONG; 5254 return -1; 5255 } 5256 5257 // All file descriptors that are opened in the Java process and not 5258 // specifically destined for a subprocess should have the close-on-exec 5259 // flag set. If we don't set it, then careless 3rd party native code 5260 // might fork and exec without closing all appropriate file descriptors 5261 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5262 // turn might: 5263 // 5264 // - cause end-of-file to fail to be detected on some file 5265 // descriptors, resulting in mysterious hangs, or 5266 // 5267 // - might cause an fopen in the subprocess to fail on a system 5268 // suffering from bug 1085341. 5269 // 5270 // (Yes, the default setting of the close-on-exec flag is a Unix 5271 // design flaw) 5272 // 5273 // See: 5274 // 1085341: 32-bit stdio routines should support file descriptors >255 5275 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5276 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5277 // 5278 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5279 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5280 // because it saves a system call and removes a small window where the flag 5281 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5282 // and we fall back to using FD_CLOEXEC (see below). 5283 #ifdef O_CLOEXEC 5284 oflag |= O_CLOEXEC; 5285 #endif 5286 5287 int fd = ::open64(path, oflag, mode); 5288 if (fd == -1) return -1; 5289 5290 //If the open succeeded, the file might still be a directory 5291 { 5292 struct stat64 buf64; 5293 int ret = ::fstat64(fd, &buf64); 5294 int st_mode = buf64.st_mode; 5295 5296 if (ret != -1) { 5297 if ((st_mode & S_IFMT) == S_IFDIR) { 5298 errno = EISDIR; 5299 ::close(fd); 5300 return -1; 5301 } 5302 } else { 5303 ::close(fd); 5304 return -1; 5305 } 5306 } 5307 5308 #ifdef FD_CLOEXEC 5309 // Validate that the use of the O_CLOEXEC flag on open above worked. 5310 // With recent kernels, we will perform this check exactly once. 5311 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5312 if (!O_CLOEXEC_is_known_to_work) { 5313 int flags = ::fcntl(fd, F_GETFD); 5314 if (flags != -1) { 5315 if ((flags & FD_CLOEXEC) != 0) 5316 O_CLOEXEC_is_known_to_work = 1; 5317 else 5318 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5319 } 5320 } 5321 #endif 5322 5323 return fd; 5324 } 5325 5326 5327 // create binary file, rewriting existing file if required 5328 int os::create_binary_file(const char* path, bool rewrite_existing) { 5329 int oflags = O_WRONLY | O_CREAT; 5330 if (!rewrite_existing) { 5331 oflags |= O_EXCL; 5332 } 5333 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5334 } 5335 5336 // return current position of file pointer 5337 jlong os::current_file_offset(int fd) { 5338 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5339 } 5340 5341 // move file pointer to the specified offset 5342 jlong os::seek_to_file_offset(int fd, jlong offset) { 5343 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5344 } 5345 5346 // This code originates from JDK's sysAvailable 5347 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5348 5349 int os::available(int fd, jlong *bytes) { 5350 jlong cur, end; 5351 int mode; 5352 struct stat64 buf64; 5353 5354 if (::fstat64(fd, &buf64) >= 0) { 5355 mode = buf64.st_mode; 5356 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5357 int n; 5358 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5359 *bytes = n; 5360 return 1; 5361 } 5362 } 5363 } 5364 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5365 return 0; 5366 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5367 return 0; 5368 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5369 return 0; 5370 } 5371 *bytes = end - cur; 5372 return 1; 5373 } 5374 5375 // Map a block of memory. 5376 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5377 char *addr, size_t bytes, bool read_only, 5378 bool allow_exec) { 5379 int prot; 5380 int flags = MAP_PRIVATE; 5381 5382 if (read_only) { 5383 prot = PROT_READ; 5384 } else { 5385 prot = PROT_READ | PROT_WRITE; 5386 } 5387 5388 if (allow_exec) { 5389 prot |= PROT_EXEC; 5390 } 5391 5392 if (addr != NULL) { 5393 flags |= MAP_FIXED; 5394 } 5395 5396 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5397 fd, file_offset); 5398 if (mapped_address == MAP_FAILED) { 5399 return NULL; 5400 } 5401 return mapped_address; 5402 } 5403 5404 5405 // Remap a block of memory. 5406 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5407 char *addr, size_t bytes, bool read_only, 5408 bool allow_exec) { 5409 // same as map_memory() on this OS 5410 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5411 allow_exec); 5412 } 5413 5414 5415 // Unmap a block of memory. 5416 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5417 return munmap(addr, bytes) == 0; 5418 } 5419 5420 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5421 5422 static clockid_t thread_cpu_clockid(Thread* thread) { 5423 pthread_t tid = thread->osthread()->pthread_id(); 5424 clockid_t clockid; 5425 5426 // Get thread clockid 5427 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5428 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5429 return clockid; 5430 } 5431 5432 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5433 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5434 // of a thread. 5435 // 5436 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5437 // the fast estimate available on the platform. 5438 5439 jlong os::current_thread_cpu_time() { 5440 if (os::Linux::supports_fast_thread_cpu_time()) { 5441 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5442 } else { 5443 // return user + sys since the cost is the same 5444 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5445 } 5446 } 5447 5448 jlong os::thread_cpu_time(Thread* thread) { 5449 // consistent with what current_thread_cpu_time() returns 5450 if (os::Linux::supports_fast_thread_cpu_time()) { 5451 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5452 } else { 5453 return slow_thread_cpu_time(thread, true /* user + sys */); 5454 } 5455 } 5456 5457 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5458 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5459 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5460 } else { 5461 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5462 } 5463 } 5464 5465 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5466 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5467 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5468 } else { 5469 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5470 } 5471 } 5472 5473 // -1 on error. 5474 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5475 pid_t tid = thread->osthread()->thread_id(); 5476 char *s; 5477 char stat[2048]; 5478 int statlen; 5479 char proc_name[64]; 5480 int count; 5481 long sys_time, user_time; 5482 char cdummy; 5483 int idummy; 5484 long ldummy; 5485 FILE *fp; 5486 5487 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5488 fp = fopen(proc_name, "r"); 5489 if (fp == NULL) return -1; 5490 statlen = fread(stat, 1, 2047, fp); 5491 stat[statlen] = '\0'; 5492 fclose(fp); 5493 5494 // Skip pid and the command string. Note that we could be dealing with 5495 // weird command names, e.g. user could decide to rename java launcher 5496 // to "java 1.4.2 :)", then the stat file would look like 5497 // 1234 (java 1.4.2 :)) R ... ... 5498 // We don't really need to know the command string, just find the last 5499 // occurrence of ")" and then start parsing from there. See bug 4726580. 5500 s = strrchr(stat, ')'); 5501 if (s == NULL) return -1; 5502 5503 // Skip blank chars 5504 do { s++; } while (s && isspace(*s)); 5505 5506 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5507 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5508 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5509 &user_time, &sys_time); 5510 if (count != 13) return -1; 5511 if (user_sys_cpu_time) { 5512 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5513 } else { 5514 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5515 } 5516 } 5517 5518 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5519 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5520 info_ptr->may_skip_backward = false; // elapsed time not wall time 5521 info_ptr->may_skip_forward = false; // elapsed time not wall time 5522 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5523 } 5524 5525 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5526 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5527 info_ptr->may_skip_backward = false; // elapsed time not wall time 5528 info_ptr->may_skip_forward = false; // elapsed time not wall time 5529 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5530 } 5531 5532 bool os::is_thread_cpu_time_supported() { 5533 return true; 5534 } 5535 5536 // System loadavg support. Returns -1 if load average cannot be obtained. 5537 // Linux doesn't yet have a (official) notion of processor sets, 5538 // so just return the system wide load average. 5539 int os::loadavg(double loadavg[], int nelem) { 5540 return ::getloadavg(loadavg, nelem); 5541 } 5542 5543 void os::pause() { 5544 char filename[MAX_PATH]; 5545 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5546 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5547 } else { 5548 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5549 } 5550 5551 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5552 if (fd != -1) { 5553 struct stat buf; 5554 ::close(fd); 5555 while (::stat(filename, &buf) == 0) { 5556 (void)::poll(NULL, 0, 100); 5557 } 5558 } else { 5559 jio_fprintf(stderr, 5560 "Could not open pause file '%s', continuing immediately.\n", filename); 5561 } 5562 } 5563 5564 5565 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5566 // comment paragraphs are worth repeating here: 5567 // 5568 // Assumption: 5569 // Only one parker can exist on an event, which is why we allocate 5570 // them per-thread. Multiple unparkers can coexist. 5571 // 5572 // _Event serves as a restricted-range semaphore. 5573 // -1 : thread is blocked, i.e. there is a waiter 5574 // 0 : neutral: thread is running or ready, 5575 // could have been signaled after a wait started 5576 // 1 : signaled - thread is running or ready 5577 // 5578 5579 // utility to compute the abstime argument to timedwait: 5580 // millis is the relative timeout time 5581 // abstime will be the absolute timeout time 5582 // TODO: replace compute_abstime() with unpackTime() 5583 5584 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5585 if (millis < 0) millis = 0; 5586 5587 jlong seconds = millis / 1000; 5588 millis %= 1000; 5589 if (seconds > 50000000) { // see man cond_timedwait(3T) 5590 seconds = 50000000; 5591 } 5592 5593 if (os::supports_monotonic_clock()) { 5594 struct timespec now; 5595 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5596 assert_status(status == 0, status, "clock_gettime"); 5597 abstime->tv_sec = now.tv_sec + seconds; 5598 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5599 if (nanos >= NANOSECS_PER_SEC) { 5600 abstime->tv_sec += 1; 5601 nanos -= NANOSECS_PER_SEC; 5602 } 5603 abstime->tv_nsec = nanos; 5604 } else { 5605 struct timeval now; 5606 int status = gettimeofday(&now, NULL); 5607 assert(status == 0, "gettimeofday"); 5608 abstime->tv_sec = now.tv_sec + seconds; 5609 long usec = now.tv_usec + millis * 1000; 5610 if (usec >= 1000000) { 5611 abstime->tv_sec += 1; 5612 usec -= 1000000; 5613 } 5614 abstime->tv_nsec = usec * 1000; 5615 } 5616 return abstime; 5617 } 5618 5619 void os::PlatformEvent::park() { // AKA "down()" 5620 // Transitions for _Event: 5621 // -1 => -1 : illegal 5622 // 1 => 0 : pass - return immediately 5623 // 0 => -1 : block; then set _Event to 0 before returning 5624 5625 // Invariant: Only the thread associated with the Event/PlatformEvent 5626 // may call park(). 5627 // TODO: assert that _Assoc != NULL or _Assoc == Self 5628 assert(_nParked == 0, "invariant"); 5629 5630 int v; 5631 for (;;) { 5632 v = _Event; 5633 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5634 } 5635 guarantee(v >= 0, "invariant"); 5636 if (v == 0) { 5637 // Do this the hard way by blocking ... 5638 int status = pthread_mutex_lock(_mutex); 5639 assert_status(status == 0, status, "mutex_lock"); 5640 guarantee(_nParked == 0, "invariant"); 5641 ++_nParked; 5642 while (_Event < 0) { 5643 status = pthread_cond_wait(_cond, _mutex); 5644 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5645 // Treat this the same as if the wait was interrupted 5646 if (status == ETIME) { status = EINTR; } 5647 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5648 } 5649 --_nParked; 5650 5651 _Event = 0; 5652 status = pthread_mutex_unlock(_mutex); 5653 assert_status(status == 0, status, "mutex_unlock"); 5654 // Paranoia to ensure our locked and lock-free paths interact 5655 // correctly with each other. 5656 OrderAccess::fence(); 5657 } 5658 guarantee(_Event >= 0, "invariant"); 5659 } 5660 5661 int os::PlatformEvent::park(jlong millis) { 5662 // Transitions for _Event: 5663 // -1 => -1 : illegal 5664 // 1 => 0 : pass - return immediately 5665 // 0 => -1 : block; then set _Event to 0 before returning 5666 5667 guarantee(_nParked == 0, "invariant"); 5668 5669 int v; 5670 for (;;) { 5671 v = _Event; 5672 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5673 } 5674 guarantee(v >= 0, "invariant"); 5675 if (v != 0) return OS_OK; 5676 5677 // We do this the hard way, by blocking the thread. 5678 // Consider enforcing a minimum timeout value. 5679 struct timespec abst; 5680 compute_abstime(&abst, millis); 5681 5682 int ret = OS_TIMEOUT; 5683 int status = pthread_mutex_lock(_mutex); 5684 assert_status(status == 0, status, "mutex_lock"); 5685 guarantee(_nParked == 0, "invariant"); 5686 ++_nParked; 5687 5688 // Object.wait(timo) will return because of 5689 // (a) notification 5690 // (b) timeout 5691 // (c) thread.interrupt 5692 // 5693 // Thread.interrupt and object.notify{All} both call Event::set. 5694 // That is, we treat thread.interrupt as a special case of notification. 5695 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5696 // We assume all ETIME returns are valid. 5697 // 5698 // TODO: properly differentiate simultaneous notify+interrupt. 5699 // In that case, we should propagate the notify to another waiter. 5700 5701 while (_Event < 0) { 5702 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5703 assert_status(status == 0 || status == EINTR || 5704 status == ETIME || status == ETIMEDOUT, 5705 status, "cond_timedwait"); 5706 if (!FilterSpuriousWakeups) break; // previous semantics 5707 if (status == ETIME || status == ETIMEDOUT) break; 5708 // We consume and ignore EINTR and spurious wakeups. 5709 } 5710 --_nParked; 5711 if (_Event >= 0) { 5712 ret = OS_OK; 5713 } 5714 _Event = 0; 5715 status = pthread_mutex_unlock(_mutex); 5716 assert_status(status == 0, status, "mutex_unlock"); 5717 assert(_nParked == 0, "invariant"); 5718 // Paranoia to ensure our locked and lock-free paths interact 5719 // correctly with each other. 5720 OrderAccess::fence(); 5721 return ret; 5722 } 5723 5724 void os::PlatformEvent::unpark() { 5725 // Transitions for _Event: 5726 // 0 => 1 : just return 5727 // 1 => 1 : just return 5728 // -1 => either 0 or 1; must signal target thread 5729 // That is, we can safely transition _Event from -1 to either 5730 // 0 or 1. 5731 // See also: "Semaphores in Plan 9" by Mullender & Cox 5732 // 5733 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5734 // that it will take two back-to-back park() calls for the owning 5735 // thread to block. This has the benefit of forcing a spurious return 5736 // from the first park() call after an unpark() call which will help 5737 // shake out uses of park() and unpark() without condition variables. 5738 5739 if (Atomic::xchg(1, &_Event) >= 0) return; 5740 5741 // Wait for the thread associated with the event to vacate 5742 int status = pthread_mutex_lock(_mutex); 5743 assert_status(status == 0, status, "mutex_lock"); 5744 int AnyWaiters = _nParked; 5745 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5746 status = pthread_mutex_unlock(_mutex); 5747 assert_status(status == 0, status, "mutex_unlock"); 5748 if (AnyWaiters != 0) { 5749 // Note that we signal() *after* dropping the lock for "immortal" Events. 5750 // This is safe and avoids a common class of futile wakeups. In rare 5751 // circumstances this can cause a thread to return prematurely from 5752 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5753 // will simply re-test the condition and re-park itself. 5754 // This provides particular benefit if the underlying platform does not 5755 // provide wait morphing. 5756 status = pthread_cond_signal(_cond); 5757 assert_status(status == 0, status, "cond_signal"); 5758 } 5759 } 5760 5761 5762 // JSR166 5763 // ------------------------------------------------------- 5764 5765 // The solaris and linux implementations of park/unpark are fairly 5766 // conservative for now, but can be improved. They currently use a 5767 // mutex/condvar pair, plus a a count. 5768 // Park decrements count if > 0, else does a condvar wait. Unpark 5769 // sets count to 1 and signals condvar. Only one thread ever waits 5770 // on the condvar. Contention seen when trying to park implies that someone 5771 // is unparking you, so don't wait. And spurious returns are fine, so there 5772 // is no need to track notifications. 5773 5774 // This code is common to linux and solaris and will be moved to a 5775 // common place in dolphin. 5776 // 5777 // The passed in time value is either a relative time in nanoseconds 5778 // or an absolute time in milliseconds. Either way it has to be unpacked 5779 // into suitable seconds and nanoseconds components and stored in the 5780 // given timespec structure. 5781 // Given time is a 64-bit value and the time_t used in the timespec is only 5782 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5783 // overflow if times way in the future are given. Further on Solaris versions 5784 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5785 // number of seconds, in abstime, is less than current_time + 100,000,000. 5786 // As it will be 28 years before "now + 100000000" will overflow we can 5787 // ignore overflow and just impose a hard-limit on seconds using the value 5788 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5789 // years from "now". 5790 5791 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5792 assert(time > 0, "convertTime"); 5793 time_t max_secs = 0; 5794 5795 if (!os::supports_monotonic_clock() || isAbsolute) { 5796 struct timeval now; 5797 int status = gettimeofday(&now, NULL); 5798 assert(status == 0, "gettimeofday"); 5799 5800 max_secs = now.tv_sec + MAX_SECS; 5801 5802 if (isAbsolute) { 5803 jlong secs = time / 1000; 5804 if (secs > max_secs) { 5805 absTime->tv_sec = max_secs; 5806 } else { 5807 absTime->tv_sec = secs; 5808 } 5809 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5810 } else { 5811 jlong secs = time / NANOSECS_PER_SEC; 5812 if (secs >= MAX_SECS) { 5813 absTime->tv_sec = max_secs; 5814 absTime->tv_nsec = 0; 5815 } else { 5816 absTime->tv_sec = now.tv_sec + secs; 5817 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5818 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5819 absTime->tv_nsec -= NANOSECS_PER_SEC; 5820 ++absTime->tv_sec; // note: this must be <= max_secs 5821 } 5822 } 5823 } 5824 } else { 5825 // must be relative using monotonic clock 5826 struct timespec now; 5827 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5828 assert_status(status == 0, status, "clock_gettime"); 5829 max_secs = now.tv_sec + MAX_SECS; 5830 jlong secs = time / NANOSECS_PER_SEC; 5831 if (secs >= MAX_SECS) { 5832 absTime->tv_sec = max_secs; 5833 absTime->tv_nsec = 0; 5834 } else { 5835 absTime->tv_sec = now.tv_sec + secs; 5836 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5837 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5838 absTime->tv_nsec -= NANOSECS_PER_SEC; 5839 ++absTime->tv_sec; // note: this must be <= max_secs 5840 } 5841 } 5842 } 5843 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5844 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5845 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5846 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5847 } 5848 5849 void Parker::park(bool isAbsolute, jlong time) { 5850 // Ideally we'd do something useful while spinning, such 5851 // as calling unpackTime(). 5852 5853 // Optional fast-path check: 5854 // Return immediately if a permit is available. 5855 // We depend on Atomic::xchg() having full barrier semantics 5856 // since we are doing a lock-free update to _counter. 5857 if (Atomic::xchg(0, &_counter) > 0) return; 5858 5859 Thread* thread = Thread::current(); 5860 assert(thread->is_Java_thread(), "Must be JavaThread"); 5861 JavaThread *jt = (JavaThread *)thread; 5862 5863 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5864 // Check interrupt before trying to wait 5865 if (Thread::is_interrupted(thread, false)) { 5866 return; 5867 } 5868 5869 // Next, demultiplex/decode time arguments 5870 timespec absTime; 5871 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5872 return; 5873 } 5874 if (time > 0) { 5875 unpackTime(&absTime, isAbsolute, time); 5876 } 5877 5878 5879 // Enter safepoint region 5880 // Beware of deadlocks such as 6317397. 5881 // The per-thread Parker:: mutex is a classic leaf-lock. 5882 // In particular a thread must never block on the Threads_lock while 5883 // holding the Parker:: mutex. If safepoints are pending both the 5884 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5885 ThreadBlockInVM tbivm(jt); 5886 5887 // Don't wait if cannot get lock since interference arises from 5888 // unblocking. Also. check interrupt before trying wait 5889 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5890 return; 5891 } 5892 5893 int status; 5894 if (_counter > 0) { // no wait needed 5895 _counter = 0; 5896 status = pthread_mutex_unlock(_mutex); 5897 assert_status(status == 0, status, "invariant"); 5898 // Paranoia to ensure our locked and lock-free paths interact 5899 // correctly with each other and Java-level accesses. 5900 OrderAccess::fence(); 5901 return; 5902 } 5903 5904 #ifdef ASSERT 5905 // Don't catch signals while blocked; let the running threads have the signals. 5906 // (This allows a debugger to break into the running thread.) 5907 sigset_t oldsigs; 5908 sigemptyset(&oldsigs); 5909 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5910 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5911 #endif 5912 5913 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5914 jt->set_suspend_equivalent(); 5915 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5916 5917 assert(_cur_index == -1, "invariant"); 5918 if (time == 0) { 5919 _cur_index = REL_INDEX; // arbitrary choice when not timed 5920 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5921 } else { 5922 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5923 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5924 } 5925 _cur_index = -1; 5926 assert_status(status == 0 || status == EINTR || 5927 status == ETIME || status == ETIMEDOUT, 5928 status, "cond_timedwait"); 5929 5930 #ifdef ASSERT 5931 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5932 #endif 5933 5934 _counter = 0; 5935 status = pthread_mutex_unlock(_mutex); 5936 assert_status(status == 0, status, "invariant"); 5937 // Paranoia to ensure our locked and lock-free paths interact 5938 // correctly with each other and Java-level accesses. 5939 OrderAccess::fence(); 5940 5941 // If externally suspended while waiting, re-suspend 5942 if (jt->handle_special_suspend_equivalent_condition()) { 5943 jt->java_suspend_self(); 5944 } 5945 } 5946 5947 void Parker::unpark() { 5948 int status = pthread_mutex_lock(_mutex); 5949 assert_status(status == 0, status, "invariant"); 5950 const int s = _counter; 5951 _counter = 1; 5952 // must capture correct index before unlocking 5953 int index = _cur_index; 5954 status = pthread_mutex_unlock(_mutex); 5955 assert_status(status == 0, status, "invariant"); 5956 if (s < 1 && index != -1) { 5957 // thread is definitely parked 5958 status = pthread_cond_signal(&_cond[index]); 5959 assert_status(status == 0, status, "invariant"); 5960 } 5961 } 5962 5963 5964 extern char** environ; 5965 5966 // Run the specified command in a separate process. Return its exit value, 5967 // or -1 on failure (e.g. can't fork a new process). 5968 // Unlike system(), this function can be called from signal handler. It 5969 // doesn't block SIGINT et al. 5970 int os::fork_and_exec(char* cmd) { 5971 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5972 5973 pid_t pid = fork(); 5974 5975 if (pid < 0) { 5976 // fork failed 5977 return -1; 5978 5979 } else if (pid == 0) { 5980 // child process 5981 5982 execve("/bin/sh", (char* const*)argv, environ); 5983 5984 // execve failed 5985 _exit(-1); 5986 5987 } else { 5988 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5989 // care about the actual exit code, for now. 5990 5991 int status; 5992 5993 // Wait for the child process to exit. This returns immediately if 5994 // the child has already exited. */ 5995 while (waitpid(pid, &status, 0) < 0) { 5996 switch (errno) { 5997 case ECHILD: return 0; 5998 case EINTR: break; 5999 default: return -1; 6000 } 6001 } 6002 6003 if (WIFEXITED(status)) { 6004 // The child exited normally; get its exit code. 6005 return WEXITSTATUS(status); 6006 } else if (WIFSIGNALED(status)) { 6007 // The child exited because of a signal 6008 // The best value to return is 0x80 + signal number, 6009 // because that is what all Unix shells do, and because 6010 // it allows callers to distinguish between process exit and 6011 // process death by signal. 6012 return 0x80 + WTERMSIG(status); 6013 } else { 6014 // Unknown exit code; pass it through 6015 return status; 6016 } 6017 } 6018 } 6019 6020 // is_headless_jre() 6021 // 6022 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 6023 // in order to report if we are running in a headless jre 6024 // 6025 // Since JDK8 xawt/libmawt.so was moved into the same directory 6026 // as libawt.so, and renamed libawt_xawt.so 6027 // 6028 bool os::is_headless_jre() { 6029 struct stat statbuf; 6030 char buf[MAXPATHLEN]; 6031 char libmawtpath[MAXPATHLEN]; 6032 const char *xawtstr = "/xawt/libmawt.so"; 6033 const char *new_xawtstr = "/libawt_xawt.so"; 6034 char *p; 6035 6036 // Get path to libjvm.so 6037 os::jvm_path(buf, sizeof(buf)); 6038 6039 // Get rid of libjvm.so 6040 p = strrchr(buf, '/'); 6041 if (p == NULL) { 6042 return false; 6043 } else { 6044 *p = '\0'; 6045 } 6046 6047 // Get rid of client or server 6048 p = strrchr(buf, '/'); 6049 if (p == NULL) { 6050 return false; 6051 } else { 6052 *p = '\0'; 6053 } 6054 6055 // check xawt/libmawt.so 6056 strcpy(libmawtpath, buf); 6057 strcat(libmawtpath, xawtstr); 6058 if (::stat(libmawtpath, &statbuf) == 0) return false; 6059 6060 // check libawt_xawt.so 6061 strcpy(libmawtpath, buf); 6062 strcat(libmawtpath, new_xawtstr); 6063 if (::stat(libmawtpath, &statbuf) == 0) return false; 6064 6065 return true; 6066 } 6067 6068 // Get the default path to the core file 6069 // Returns the length of the string 6070 int os::get_core_path(char* buffer, size_t bufferSize) { 6071 /* 6072 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 6073 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 6074 */ 6075 const int core_pattern_len = 129; 6076 char core_pattern[core_pattern_len] = {0}; 6077 6078 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 6079 if (core_pattern_file == -1) { 6080 return -1; 6081 } 6082 6083 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 6084 ::close(core_pattern_file); 6085 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 6086 return -1; 6087 } 6088 if (core_pattern[ret-1] == '\n') { 6089 core_pattern[ret-1] = '\0'; 6090 } else { 6091 core_pattern[ret] = '\0'; 6092 } 6093 6094 char *pid_pos = strstr(core_pattern, "%p"); 6095 int written; 6096 6097 if (core_pattern[0] == '/') { 6098 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 6099 } else { 6100 char cwd[PATH_MAX]; 6101 6102 const char* p = get_current_directory(cwd, PATH_MAX); 6103 if (p == NULL) { 6104 return -1; 6105 } 6106 6107 if (core_pattern[0] == '|') { 6108 written = jio_snprintf(buffer, bufferSize, 6109 "\"%s\" (or dumping to %s/core.%d)", 6110 &core_pattern[1], p, current_process_id()); 6111 } else { 6112 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 6113 } 6114 } 6115 6116 if (written < 0) { 6117 return -1; 6118 } 6119 6120 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 6121 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 6122 6123 if (core_uses_pid_file != -1) { 6124 char core_uses_pid = 0; 6125 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 6126 ::close(core_uses_pid_file); 6127 6128 if (core_uses_pid == '1') { 6129 jio_snprintf(buffer + written, bufferSize - written, 6130 ".%d", current_process_id()); 6131 } 6132 } 6133 } 6134 6135 return strlen(buffer); 6136 } 6137 6138 bool os::start_debugging(char *buf, int buflen) { 6139 int len = (int)strlen(buf); 6140 char *p = &buf[len]; 6141 6142 jio_snprintf(p, buflen-len, 6143 "\n\n" 6144 "Do you want to debug the problem?\n\n" 6145 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6146 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6147 "Otherwise, press RETURN to abort...", 6148 os::current_process_id(), os::current_process_id(), 6149 os::current_thread_id(), os::current_thread_id()); 6150 6151 bool yes = os::message_box("Unexpected Error", buf); 6152 6153 if (yes) { 6154 // yes, user asked VM to launch debugger 6155 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d", 6156 os::current_process_id(), os::current_process_id()); 6157 6158 os::fork_and_exec(buf); 6159 yes = false; 6160 } 6161 return yes; 6162 } 6163 6164 6165 // Java/Compiler thread: 6166 // 6167 // Low memory addresses 6168 // P0 +------------------------+ 6169 // | |\ Java thread created by VM does not have glibc 6170 // | glibc guard page | - guard page, attached Java thread usually has 6171 // | |/ 1 glibc guard page. 6172 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6173 // | |\ 6174 // | HotSpot Guard Pages | - red, yellow and reserved pages 6175 // | |/ 6176 // +------------------------+ JavaThread::stack_reserved_zone_base() 6177 // | |\ 6178 // | Normal Stack | - 6179 // | |/ 6180 // P2 +------------------------+ Thread::stack_base() 6181 // 6182 // Non-Java thread: 6183 // 6184 // Low memory addresses 6185 // P0 +------------------------+ 6186 // | |\ 6187 // | glibc guard page | - usually 1 page 6188 // | |/ 6189 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size() 6190 // | |\ 6191 // | Normal Stack | - 6192 // | |/ 6193 // P2 +------------------------+ Thread::stack_base() 6194 // 6195 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size 6196 // returned from pthread_attr_getstack(). 6197 // ** Due to NPTL implementation error, linux takes the glibc guard page out 6198 // of the stack size given in pthread_attr. We work around this for 6199 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.) 6200 // 6201 #ifndef ZERO 6202 static void current_stack_region(address * bottom, size_t * size) { 6203 if (os::Linux::is_initial_thread()) { 6204 // initial thread needs special handling because pthread_getattr_np() 6205 // may return bogus value. 6206 *bottom = os::Linux::initial_thread_stack_bottom(); 6207 *size = os::Linux::initial_thread_stack_size(); 6208 } else { 6209 pthread_attr_t attr; 6210 6211 int rslt = pthread_getattr_np(pthread_self(), &attr); 6212 6213 // JVM needs to know exact stack location, abort if it fails 6214 if (rslt != 0) { 6215 if (rslt == ENOMEM) { 6216 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np"); 6217 } else { 6218 fatal("pthread_getattr_np failed with error = %d", rslt); 6219 } 6220 } 6221 6222 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) { 6223 fatal("Cannot locate current stack attributes!"); 6224 } 6225 6226 // Work around NPTL stack guard error. 6227 size_t guard_size = 0; 6228 rslt = pthread_attr_getguardsize(&attr, &guard_size); 6229 if (rslt != 0) { 6230 fatal("pthread_attr_getguardsize failed with error = %d", rslt); 6231 } 6232 *bottom += guard_size; 6233 *size -= guard_size; 6234 6235 pthread_attr_destroy(&attr); 6236 6237 } 6238 assert(os::current_stack_pointer() >= *bottom && 6239 os::current_stack_pointer() < *bottom + *size, "just checking"); 6240 } 6241 6242 address os::current_stack_base() { 6243 address bottom; 6244 size_t size; 6245 current_stack_region(&bottom, &size); 6246 return (bottom + size); 6247 } 6248 6249 size_t os::current_stack_size() { 6250 // This stack size includes the usable stack and HotSpot guard pages 6251 // (for the threads that have Hotspot guard pages). 6252 address bottom; 6253 size_t size; 6254 current_stack_region(&bottom, &size); 6255 return size; 6256 } 6257 #endif 6258 6259 static inline struct timespec get_mtime(const char* filename) { 6260 struct stat st; 6261 int ret = os::stat(filename, &st); 6262 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno)); 6263 return st.st_mtim; 6264 } 6265 6266 int os::compare_file_modified_times(const char* file1, const char* file2) { 6267 struct timespec filetime1 = get_mtime(file1); 6268 struct timespec filetime2 = get_mtime(file2); 6269 int diff = filetime1.tv_sec - filetime2.tv_sec; 6270 if (diff == 0) { 6271 return filetime1.tv_nsec - filetime2.tv_nsec; 6272 } 6273 return diff; 6274 } 6275 6276 /////////////// Unit tests /////////////// 6277 6278 #ifndef PRODUCT 6279 6280 #define test_log(...) \ 6281 do { \ 6282 if (VerboseInternalVMTests) { \ 6283 tty->print_cr(__VA_ARGS__); \ 6284 tty->flush(); \ 6285 } \ 6286 } while (false) 6287 6288 class TestReserveMemorySpecial : AllStatic { 6289 public: 6290 static void small_page_write(void* addr, size_t size) { 6291 size_t page_size = os::vm_page_size(); 6292 6293 char* end = (char*)addr + size; 6294 for (char* p = (char*)addr; p < end; p += page_size) { 6295 *p = 1; 6296 } 6297 } 6298 6299 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6300 if (!UseHugeTLBFS) { 6301 return; 6302 } 6303 6304 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6305 6306 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6307 6308 if (addr != NULL) { 6309 small_page_write(addr, size); 6310 6311 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6312 } 6313 } 6314 6315 static void test_reserve_memory_special_huge_tlbfs_only() { 6316 if (!UseHugeTLBFS) { 6317 return; 6318 } 6319 6320 size_t lp = os::large_page_size(); 6321 6322 for (size_t size = lp; size <= lp * 10; size += lp) { 6323 test_reserve_memory_special_huge_tlbfs_only(size); 6324 } 6325 } 6326 6327 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6328 size_t lp = os::large_page_size(); 6329 size_t ag = os::vm_allocation_granularity(); 6330 6331 // sizes to test 6332 const size_t sizes[] = { 6333 lp, lp + ag, lp + lp / 2, lp * 2, 6334 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6335 lp * 10, lp * 10 + lp / 2 6336 }; 6337 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6338 6339 // For each size/alignment combination, we test three scenarios: 6340 // 1) with req_addr == NULL 6341 // 2) with a non-null req_addr at which we expect to successfully allocate 6342 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6343 // expect the allocation to either fail or to ignore req_addr 6344 6345 // Pre-allocate two areas; they shall be as large as the largest allocation 6346 // and aligned to the largest alignment we will be testing. 6347 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6348 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6349 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6350 -1, 0); 6351 assert(mapping1 != MAP_FAILED, "should work"); 6352 6353 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6354 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6355 -1, 0); 6356 assert(mapping2 != MAP_FAILED, "should work"); 6357 6358 // Unmap the first mapping, but leave the second mapping intact: the first 6359 // mapping will serve as a value for a "good" req_addr (case 2). The second 6360 // mapping, still intact, as "bad" req_addr (case 3). 6361 ::munmap(mapping1, mapping_size); 6362 6363 // Case 1 6364 test_log("%s, req_addr NULL:", __FUNCTION__); 6365 test_log("size align result"); 6366 6367 for (int i = 0; i < num_sizes; i++) { 6368 const size_t size = sizes[i]; 6369 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6370 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6371 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6372 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6373 if (p != NULL) { 6374 assert(is_ptr_aligned(p, alignment), "must be"); 6375 small_page_write(p, size); 6376 os::Linux::release_memory_special_huge_tlbfs(p, size); 6377 } 6378 } 6379 } 6380 6381 // Case 2 6382 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6383 test_log("size align req_addr result"); 6384 6385 for (int i = 0; i < num_sizes; i++) { 6386 const size_t size = sizes[i]; 6387 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6388 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6389 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6390 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6391 size, alignment, p2i(req_addr), p2i(p), 6392 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6393 if (p != NULL) { 6394 assert(p == req_addr, "must be"); 6395 small_page_write(p, size); 6396 os::Linux::release_memory_special_huge_tlbfs(p, size); 6397 } 6398 } 6399 } 6400 6401 // Case 3 6402 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6403 test_log("size align req_addr result"); 6404 6405 for (int i = 0; i < num_sizes; i++) { 6406 const size_t size = sizes[i]; 6407 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6408 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6409 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6410 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6411 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6412 // as the area around req_addr contains already existing mappings, the API should always 6413 // return NULL (as per contract, it cannot return another address) 6414 assert(p == NULL, "must be"); 6415 } 6416 } 6417 6418 ::munmap(mapping2, mapping_size); 6419 6420 } 6421 6422 static void test_reserve_memory_special_huge_tlbfs() { 6423 if (!UseHugeTLBFS) { 6424 return; 6425 } 6426 6427 test_reserve_memory_special_huge_tlbfs_only(); 6428 test_reserve_memory_special_huge_tlbfs_mixed(); 6429 } 6430 6431 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6432 if (!UseSHM) { 6433 return; 6434 } 6435 6436 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6437 6438 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6439 6440 if (addr != NULL) { 6441 assert(is_ptr_aligned(addr, alignment), "Check"); 6442 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6443 6444 small_page_write(addr, size); 6445 6446 os::Linux::release_memory_special_shm(addr, size); 6447 } 6448 } 6449 6450 static void test_reserve_memory_special_shm() { 6451 size_t lp = os::large_page_size(); 6452 size_t ag = os::vm_allocation_granularity(); 6453 6454 for (size_t size = ag; size < lp * 3; size += ag) { 6455 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6456 test_reserve_memory_special_shm(size, alignment); 6457 } 6458 } 6459 } 6460 6461 static void test() { 6462 test_reserve_memory_special_huge_tlbfs(); 6463 test_reserve_memory_special_shm(); 6464 } 6465 }; 6466 6467 void TestReserveMemorySpecial_test() { 6468 TestReserveMemorySpecial::test(); 6469 } 6470 6471 #endif