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