1 /* 2 * Copyright (c) 1999, 2015, 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 "memory/allocation.inline.hpp" 36 #include "memory/filemap.hpp" 37 #include "mutex_linux.inline.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.inline.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 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling 110 // getrusage() is prepared to handle the associated failure. 111 #ifndef RUSAGE_THREAD 112 #define RUSAGE_THREAD (1) /* only the calling thread */ 113 #endif 114 115 #define MAX_PATH (2 * K) 116 117 #define MAX_SECS 100000000 118 119 // for timer info max values which include all bits 120 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF) 121 122 #define LARGEPAGES_BIT (1 << 6) 123 //////////////////////////////////////////////////////////////////////////////// 124 // global variables 125 julong os::Linux::_physical_memory = 0; 126 127 address os::Linux::_initial_thread_stack_bottom = NULL; 128 uintptr_t os::Linux::_initial_thread_stack_size = 0; 129 130 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL; 131 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL; 132 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL; 133 Mutex* os::Linux::_createThread_lock = NULL; 134 pthread_t os::Linux::_main_thread; 135 int os::Linux::_page_size = -1; 136 const int os::Linux::_vm_default_page_size = (8 * K); 137 bool os::Linux::_supports_fast_thread_cpu_time = false; 138 const char * os::Linux::_glibc_version = NULL; 139 const char * os::Linux::_libpthread_version = NULL; 140 pthread_condattr_t os::Linux::_condattr[1]; 141 142 static jlong initial_time_count=0; 143 144 static int clock_tics_per_sec = 100; 145 146 // For diagnostics to print a message once. see run_periodic_checks 147 static sigset_t check_signal_done; 148 static bool check_signals = true; 149 150 // Signal number used to suspend/resume a thread 151 152 // do not use any signal number less than SIGSEGV, see 4355769 153 static int SR_signum = SIGUSR2; 154 sigset_t SR_sigset; 155 156 // Declarations 157 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time); 158 159 // utility functions 160 161 static int SR_initialize(); 162 163 julong os::available_memory() { 164 return Linux::available_memory(); 165 } 166 167 julong os::Linux::available_memory() { 168 // values in struct sysinfo are "unsigned long" 169 struct sysinfo si; 170 sysinfo(&si); 171 172 return (julong)si.freeram * si.mem_unit; 173 } 174 175 julong os::physical_memory() { 176 return Linux::physical_memory(); 177 } 178 179 // Return true if user is running as root. 180 181 bool os::have_special_privileges() { 182 static bool init = false; 183 static bool privileges = false; 184 if (!init) { 185 privileges = (getuid() != geteuid()) || (getgid() != getegid()); 186 init = true; 187 } 188 return privileges; 189 } 190 191 192 #ifndef SYS_gettid 193 // i386: 224, ia64: 1105, amd64: 186, sparc 143 194 #ifdef __ia64__ 195 #define SYS_gettid 1105 196 #else 197 #ifdef __i386__ 198 #define SYS_gettid 224 199 #else 200 #ifdef __amd64__ 201 #define SYS_gettid 186 202 #else 203 #ifdef __sparc__ 204 #define SYS_gettid 143 205 #else 206 #error define gettid for the arch 207 #endif 208 #endif 209 #endif 210 #endif 211 #endif 212 213 // Cpu architecture string 214 static char cpu_arch[] = HOTSPOT_LIB_ARCH; 215 216 217 // pid_t gettid() 218 // 219 // Returns the kernel thread id of the currently running thread. Kernel 220 // thread id is used to access /proc. 221 pid_t os::Linux::gettid() { 222 int rslt = syscall(SYS_gettid); 223 assert(rslt != -1, "must be."); // old linuxthreads implementation? 224 return (pid_t)rslt; 225 } 226 227 // Most versions of linux have a bug where the number of processors are 228 // determined by looking at the /proc file system. In a chroot environment, 229 // the system call returns 1. This causes the VM to act as if it is 230 // a single processor and elide locking (see is_MP() call). 231 static bool unsafe_chroot_detected = false; 232 static const char *unstable_chroot_error = "/proc file system not found.\n" 233 "Java may be unstable running multithreaded in a chroot " 234 "environment on Linux when /proc filesystem is not mounted."; 235 236 void os::Linux::initialize_system_info() { 237 set_processor_count(sysconf(_SC_NPROCESSORS_CONF)); 238 if (processor_count() == 1) { 239 pid_t pid = os::Linux::gettid(); 240 char fname[32]; 241 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid); 242 FILE *fp = fopen(fname, "r"); 243 if (fp == NULL) { 244 unsafe_chroot_detected = true; 245 } else { 246 fclose(fp); 247 } 248 } 249 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE); 250 assert(processor_count() > 0, "linux error"); 251 } 252 253 void os::init_system_properties_values() { 254 // The next steps are taken in the product version: 255 // 256 // Obtain the JAVA_HOME value from the location of libjvm.so. 257 // This library should be located at: 258 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so. 259 // 260 // If "/jre/lib/" appears at the right place in the path, then we 261 // assume libjvm.so is installed in a JDK and we use this path. 262 // 263 // Otherwise exit with message: "Could not create the Java virtual machine." 264 // 265 // The following extra steps are taken in the debugging version: 266 // 267 // If "/jre/lib/" does NOT appear at the right place in the path 268 // instead of exit check for $JAVA_HOME environment variable. 269 // 270 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>, 271 // then we append a fake suffix "hotspot/libjvm.so" to this path so 272 // it looks like libjvm.so is installed there 273 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so. 274 // 275 // Otherwise exit. 276 // 277 // Important note: if the location of libjvm.so changes this 278 // code needs to be changed accordingly. 279 280 // See ld(1): 281 // The linker uses the following search paths to locate required 282 // shared libraries: 283 // 1: ... 284 // ... 285 // 7: The default directories, normally /lib and /usr/lib. 286 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390)) 287 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib" 288 #else 289 #define DEFAULT_LIBPATH "/lib:/usr/lib" 290 #endif 291 292 // Base path of extensions installed on the system. 293 #define SYS_EXT_DIR "/usr/java/packages" 294 #define EXTENSIONS_DIR "/lib/ext" 295 296 // Buffer that fits several sprintfs. 297 // Note that the space for the colon and the trailing null are provided 298 // by the nulls included by the sizeof operator. 299 const size_t bufsize = 300 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends. 301 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir 302 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal); 303 304 // sysclasspath, java_home, dll_dir 305 { 306 char *pslash; 307 os::jvm_path(buf, bufsize); 308 309 // Found the full path to libjvm.so. 310 // Now cut the path to <java_home>/jre if we can. 311 pslash = strrchr(buf, '/'); 312 if (pslash != NULL) { 313 *pslash = '\0'; // Get rid of /libjvm.so. 314 } 315 pslash = strrchr(buf, '/'); 316 if (pslash != NULL) { 317 *pslash = '\0'; // Get rid of /{client|server|hotspot}. 318 } 319 Arguments::set_dll_dir(buf); 320 321 if (pslash != NULL) { 322 pslash = strrchr(buf, '/'); 323 if (pslash != NULL) { 324 *pslash = '\0'; // Get rid of /<arch>. 325 pslash = strrchr(buf, '/'); 326 if (pslash != NULL) { 327 *pslash = '\0'; // Get rid of /lib. 328 } 329 } 330 } 331 Arguments::set_java_home(buf); 332 set_boot_path('/', ':'); 333 } 334 335 // Where to look for native libraries. 336 // 337 // Note: Due to a legacy implementation, most of the library path 338 // is set in the launcher. This was to accomodate linking restrictions 339 // on legacy Linux implementations (which are no longer supported). 340 // Eventually, all the library path setting will be done here. 341 // 342 // However, to prevent the proliferation of improperly built native 343 // libraries, the new path component /usr/java/packages is added here. 344 // Eventually, all the library path setting will be done here. 345 { 346 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It 347 // should always exist (until the legacy problem cited above is 348 // addressed). 349 const char *v = ::getenv("LD_LIBRARY_PATH"); 350 const char *v_colon = ":"; 351 if (v == NULL) { v = ""; v_colon = ""; } 352 // That's +1 for the colon and +1 for the trailing '\0'. 353 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char, 354 strlen(v) + 1 + 355 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1, 356 mtInternal); 357 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch); 358 Arguments::set_library_path(ld_library_path); 359 FREE_C_HEAP_ARRAY(char, ld_library_path); 360 } 361 362 // Extensions directories. 363 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home()); 364 Arguments::set_ext_dirs(buf); 365 366 FREE_C_HEAP_ARRAY(char, buf); 367 368 #undef DEFAULT_LIBPATH 369 #undef SYS_EXT_DIR 370 #undef EXTENSIONS_DIR 371 } 372 373 //////////////////////////////////////////////////////////////////////////////// 374 // breakpoint support 375 376 void os::breakpoint() { 377 BREAKPOINT; 378 } 379 380 extern "C" void breakpoint() { 381 // use debugger to set breakpoint here 382 } 383 384 //////////////////////////////////////////////////////////////////////////////// 385 // signal support 386 387 debug_only(static bool signal_sets_initialized = false); 388 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs; 389 390 bool os::Linux::is_sig_ignored(int sig) { 391 struct sigaction oact; 392 sigaction(sig, (struct sigaction*)NULL, &oact); 393 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction) 394 : CAST_FROM_FN_PTR(void*, oact.sa_handler); 395 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) { 396 return true; 397 } else { 398 return false; 399 } 400 } 401 402 void os::Linux::signal_sets_init() { 403 // Should also have an assertion stating we are still single-threaded. 404 assert(!signal_sets_initialized, "Already initialized"); 405 // Fill in signals that are necessarily unblocked for all threads in 406 // the VM. Currently, we unblock the following signals: 407 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden 408 // by -Xrs (=ReduceSignalUsage)); 409 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all 410 // other threads. The "ReduceSignalUsage" boolean tells us not to alter 411 // the dispositions or masks wrt these signals. 412 // Programs embedding the VM that want to use the above signals for their 413 // own purposes must, at this time, use the "-Xrs" option to prevent 414 // interference with shutdown hooks and BREAK_SIGNAL thread dumping. 415 // (See bug 4345157, and other related bugs). 416 // In reality, though, unblocking these signals is really a nop, since 417 // these signals are not blocked by default. 418 sigemptyset(&unblocked_sigs); 419 sigemptyset(&allowdebug_blocked_sigs); 420 sigaddset(&unblocked_sigs, SIGILL); 421 sigaddset(&unblocked_sigs, SIGSEGV); 422 sigaddset(&unblocked_sigs, SIGBUS); 423 sigaddset(&unblocked_sigs, SIGFPE); 424 #if defined(PPC64) 425 sigaddset(&unblocked_sigs, SIGTRAP); 426 #endif 427 sigaddset(&unblocked_sigs, SR_signum); 428 429 if (!ReduceSignalUsage) { 430 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) { 431 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL); 432 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL); 433 } 434 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) { 435 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL); 436 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL); 437 } 438 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) { 439 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL); 440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL); 441 } 442 } 443 // Fill in signals that are blocked by all but the VM thread. 444 sigemptyset(&vm_sigs); 445 if (!ReduceSignalUsage) { 446 sigaddset(&vm_sigs, BREAK_SIGNAL); 447 } 448 debug_only(signal_sets_initialized = true); 449 450 } 451 452 // These are signals that are unblocked while a thread is running Java. 453 // (For some reason, they get blocked by default.) 454 sigset_t* os::Linux::unblocked_signals() { 455 assert(signal_sets_initialized, "Not initialized"); 456 return &unblocked_sigs; 457 } 458 459 // These are the signals that are blocked while a (non-VM) thread is 460 // running Java. Only the VM thread handles these signals. 461 sigset_t* os::Linux::vm_signals() { 462 assert(signal_sets_initialized, "Not initialized"); 463 return &vm_sigs; 464 } 465 466 // These are signals that are blocked during cond_wait to allow debugger in 467 sigset_t* os::Linux::allowdebug_blocked_signals() { 468 assert(signal_sets_initialized, "Not initialized"); 469 return &allowdebug_blocked_sigs; 470 } 471 472 void os::Linux::hotspot_sigmask(Thread* thread) { 473 474 //Save caller's signal mask before setting VM signal mask 475 sigset_t caller_sigmask; 476 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask); 477 478 OSThread* osthread = thread->osthread(); 479 osthread->set_caller_sigmask(caller_sigmask); 480 481 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL); 482 483 if (!ReduceSignalUsage) { 484 if (thread->is_VM_thread()) { 485 // Only the VM thread handles BREAK_SIGNAL ... 486 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL); 487 } else { 488 // ... all other threads block BREAK_SIGNAL 489 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL); 490 } 491 } 492 } 493 494 ////////////////////////////////////////////////////////////////////////////// 495 // detecting pthread library 496 497 void os::Linux::libpthread_init() { 498 // Save glibc and pthread version strings. 499 #if !defined(_CS_GNU_LIBC_VERSION) || \ 500 !defined(_CS_GNU_LIBPTHREAD_VERSION) 501 #error "glibc too old (< 2.3.2)" 502 #endif 503 504 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0); 505 assert(n > 0, "cannot retrieve glibc version"); 506 char *str = (char *)malloc(n, mtInternal); 507 confstr(_CS_GNU_LIBC_VERSION, str, n); 508 os::Linux::set_glibc_version(str); 509 510 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0); 511 assert(n > 0, "cannot retrieve pthread version"); 512 str = (char *)malloc(n, mtInternal); 513 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n); 514 os::Linux::set_libpthread_version(str); 515 } 516 517 ///////////////////////////////////////////////////////////////////////////// 518 // thread stack expansion 519 520 // os::Linux::manually_expand_stack() takes care of expanding the thread 521 // stack. Note that this is normally not needed: pthread stacks allocate 522 // thread stack using mmap() without MAP_NORESERVE, so the stack is already 523 // committed. Therefore it is not necessary to expand the stack manually. 524 // 525 // Manually expanding the stack was historically needed on LinuxThreads 526 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays 527 // it is kept to deal with very rare corner cases: 528 // 529 // For one, user may run the VM on an own implementation of threads 530 // whose stacks are - like the old LinuxThreads - implemented using 531 // mmap(MAP_GROWSDOWN). 532 // 533 // Also, this coding may be needed if the VM is running on the primordial 534 // thread. Normally we avoid running on the primordial thread; however, 535 // user may still invoke the VM on the primordial thread. 536 // 537 // The following historical comment describes the details about running 538 // on a thread stack allocated with mmap(MAP_GROWSDOWN): 539 540 541 // Force Linux kernel to expand current thread stack. If "bottom" is close 542 // to the stack guard, caller should block all signals. 543 // 544 // MAP_GROWSDOWN: 545 // A special mmap() flag that is used to implement thread stacks. It tells 546 // kernel that the memory region should extend downwards when needed. This 547 // allows early versions of LinuxThreads to only mmap the first few pages 548 // when creating a new thread. Linux kernel will automatically expand thread 549 // stack as needed (on page faults). 550 // 551 // However, because the memory region of a MAP_GROWSDOWN stack can grow on 552 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN 553 // region, it's hard to tell if the fault is due to a legitimate stack 554 // access or because of reading/writing non-exist memory (e.g. buffer 555 // overrun). As a rule, if the fault happens below current stack pointer, 556 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the 557 // application (see Linux kernel fault.c). 558 // 559 // This Linux feature can cause SIGSEGV when VM bangs thread stack for 560 // stack overflow detection. 561 // 562 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do 563 // not use MAP_GROWSDOWN. 564 // 565 // To get around the problem and allow stack banging on Linux, we need to 566 // manually expand thread stack after receiving the SIGSEGV. 567 // 568 // There are two ways to expand thread stack to address "bottom", we used 569 // both of them in JVM before 1.5: 570 // 1. adjust stack pointer first so that it is below "bottom", and then 571 // touch "bottom" 572 // 2. mmap() the page in question 573 // 574 // Now alternate signal stack is gone, it's harder to use 2. For instance, 575 // if current sp is already near the lower end of page 101, and we need to 576 // call mmap() to map page 100, it is possible that part of the mmap() frame 577 // will be placed in page 100. When page 100 is mapped, it is zero-filled. 578 // That will destroy the mmap() frame and cause VM to crash. 579 // 580 // The following code works by adjusting sp first, then accessing the "bottom" 581 // page to force a page fault. Linux kernel will then automatically expand the 582 // stack mapping. 583 // 584 // _expand_stack_to() assumes its frame size is less than page size, which 585 // should always be true if the function is not inlined. 586 587 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute 588 #define NOINLINE 589 #else 590 #define NOINLINE __attribute__ ((noinline)) 591 #endif 592 593 static void _expand_stack_to(address bottom) NOINLINE; 594 595 static void _expand_stack_to(address bottom) { 596 address sp; 597 size_t size; 598 volatile char *p; 599 600 // Adjust bottom to point to the largest address within the same page, it 601 // gives us a one-page buffer if alloca() allocates slightly more memory. 602 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size()); 603 bottom += os::Linux::page_size() - 1; 604 605 // sp might be slightly above current stack pointer; if that's the case, we 606 // will alloca() a little more space than necessary, which is OK. Don't use 607 // os::current_stack_pointer(), as its result can be slightly below current 608 // stack pointer, causing us to not alloca enough to reach "bottom". 609 sp = (address)&sp; 610 611 if (sp > bottom) { 612 size = sp - bottom; 613 p = (volatile char *)alloca(size); 614 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?"); 615 p[0] = '\0'; 616 } 617 } 618 619 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) { 620 assert(t!=NULL, "just checking"); 621 assert(t->osthread()->expanding_stack(), "expand should be set"); 622 assert(t->stack_base() != NULL, "stack_base was not initialized"); 623 624 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) { 625 sigset_t mask_all, old_sigset; 626 sigfillset(&mask_all); 627 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset); 628 _expand_stack_to(addr); 629 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL); 630 return true; 631 } 632 return false; 633 } 634 635 ////////////////////////////////////////////////////////////////////////////// 636 // create new thread 637 638 // Thread start routine for all newly created threads 639 static void *java_start(Thread *thread) { 640 // Try to randomize the cache line index of hot stack frames. 641 // This helps when threads of the same stack traces evict each other's 642 // cache lines. The threads can be either from the same JVM instance, or 643 // from different JVM instances. The benefit is especially true for 644 // processors with hyperthreading technology. 645 static int counter = 0; 646 int pid = os::current_process_id(); 647 alloca(((pid ^ counter++) & 7) * 128); 648 649 ThreadLocalStorage::set_thread(thread); 650 651 OSThread* osthread = thread->osthread(); 652 Monitor* sync = osthread->startThread_lock(); 653 654 osthread->set_thread_id(os::current_thread_id()); 655 656 if (UseNUMA) { 657 int lgrp_id = os::numa_get_group_id(); 658 if (lgrp_id != -1) { 659 thread->set_lgrp_id(lgrp_id); 660 } 661 } 662 // initialize signal mask for this thread 663 os::Linux::hotspot_sigmask(thread); 664 665 // initialize floating point control register 666 os::Linux::init_thread_fpu_state(); 667 668 // handshaking with parent thread 669 { 670 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag); 671 672 // notify parent thread 673 osthread->set_state(INITIALIZED); 674 sync->notify_all(); 675 676 // wait until os::start_thread() 677 while (osthread->get_state() == INITIALIZED) { 678 sync->wait(Mutex::_no_safepoint_check_flag); 679 } 680 } 681 682 // call one more level start routine 683 thread->run(); 684 685 return 0; 686 } 687 688 bool os::create_thread(Thread* thread, ThreadType thr_type, 689 size_t stack_size) { 690 assert(thread->osthread() == NULL, "caller responsible"); 691 692 // Allocate the OSThread object 693 OSThread* osthread = new OSThread(NULL, NULL); 694 if (osthread == NULL) { 695 return false; 696 } 697 698 // set the correct thread state 699 osthread->set_thread_type(thr_type); 700 701 // Initial state is ALLOCATED but not INITIALIZED 702 osthread->set_state(ALLOCATED); 703 704 thread->set_osthread(osthread); 705 706 // init thread attributes 707 pthread_attr_t attr; 708 pthread_attr_init(&attr); 709 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); 710 711 // stack size 712 // calculate stack size if it's not specified by caller 713 if (stack_size == 0) { 714 stack_size = os::Linux::default_stack_size(thr_type); 715 716 switch (thr_type) { 717 case os::java_thread: 718 // Java threads use ThreadStackSize which default value can be 719 // changed with the flag -Xss 720 assert(JavaThread::stack_size_at_create() > 0, "this should be set"); 721 stack_size = JavaThread::stack_size_at_create(); 722 break; 723 case os::compiler_thread: 724 if (CompilerThreadStackSize > 0) { 725 stack_size = (size_t)(CompilerThreadStackSize * K); 726 break; 727 } // else fall through: 728 // use VMThreadStackSize if CompilerThreadStackSize is not defined 729 case os::vm_thread: 730 case os::pgc_thread: 731 case os::cgc_thread: 732 case os::watcher_thread: 733 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K); 734 break; 735 } 736 } 737 738 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed); 739 pthread_attr_setstacksize(&attr, stack_size); 740 741 // glibc guard page 742 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type)); 743 744 ThreadState state; 745 746 { 747 pthread_t tid; 748 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread); 749 750 pthread_attr_destroy(&attr); 751 752 if (ret != 0) { 753 if (PrintMiscellaneous && (Verbose || WizardMode)) { 754 perror("pthread_create()"); 755 } 756 // Need to clean up stuff we've allocated so far 757 thread->set_osthread(NULL); 758 delete osthread; 759 return false; 760 } 761 762 // Store pthread info into the OSThread 763 osthread->set_pthread_id(tid); 764 765 // Wait until child thread is either initialized or aborted 766 { 767 Monitor* sync_with_child = osthread->startThread_lock(); 768 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 769 while ((state = osthread->get_state()) == ALLOCATED) { 770 sync_with_child->wait(Mutex::_no_safepoint_check_flag); 771 } 772 } 773 } 774 775 // Aborted due to thread limit being reached 776 if (state == ZOMBIE) { 777 thread->set_osthread(NULL); 778 delete osthread; 779 return false; 780 } 781 782 // The thread is returned suspended (in state INITIALIZED), 783 // and is started higher up in the call chain 784 assert(state == INITIALIZED, "race condition"); 785 return true; 786 } 787 788 ///////////////////////////////////////////////////////////////////////////// 789 // attach existing thread 790 791 // bootstrap the main thread 792 bool os::create_main_thread(JavaThread* thread) { 793 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread"); 794 return create_attached_thread(thread); 795 } 796 797 bool os::create_attached_thread(JavaThread* thread) { 798 #ifdef ASSERT 799 thread->verify_not_published(); 800 #endif 801 802 // Allocate the OSThread object 803 OSThread* osthread = new OSThread(NULL, NULL); 804 805 if (osthread == NULL) { 806 return false; 807 } 808 809 // Store pthread info into the OSThread 810 osthread->set_thread_id(os::Linux::gettid()); 811 osthread->set_pthread_id(::pthread_self()); 812 813 // initialize floating point control register 814 os::Linux::init_thread_fpu_state(); 815 816 // Initial thread state is RUNNABLE 817 osthread->set_state(RUNNABLE); 818 819 thread->set_osthread(osthread); 820 821 if (UseNUMA) { 822 int lgrp_id = os::numa_get_group_id(); 823 if (lgrp_id != -1) { 824 thread->set_lgrp_id(lgrp_id); 825 } 826 } 827 828 if (os::Linux::is_initial_thread()) { 829 // If current thread is initial thread, its stack is mapped on demand, 830 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map 831 // the entire stack region to avoid SEGV in stack banging. 832 // It is also useful to get around the heap-stack-gap problem on SuSE 833 // kernel (see 4821821 for details). We first expand stack to the top 834 // of yellow zone, then enable stack yellow zone (order is significant, 835 // enabling yellow zone first will crash JVM on SuSE Linux), so there 836 // is no gap between the last two virtual memory regions. 837 838 JavaThread *jt = (JavaThread *)thread; 839 address addr = jt->stack_yellow_zone_base(); 840 assert(addr != NULL, "initialization problem?"); 841 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled"); 842 843 osthread->set_expanding_stack(); 844 os::Linux::manually_expand_stack(jt, addr); 845 osthread->clear_expanding_stack(); 846 } 847 848 // initialize signal mask for this thread 849 // and save the caller's signal mask 850 os::Linux::hotspot_sigmask(thread); 851 852 return true; 853 } 854 855 void os::pd_start_thread(Thread* thread) { 856 OSThread * osthread = thread->osthread(); 857 assert(osthread->get_state() != INITIALIZED, "just checking"); 858 Monitor* sync_with_child = osthread->startThread_lock(); 859 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag); 860 sync_with_child->notify(); 861 } 862 863 // Free Linux resources related to the OSThread 864 void os::free_thread(OSThread* osthread) { 865 assert(osthread != NULL, "osthread not set"); 866 867 if (Thread::current()->osthread() == osthread) { 868 // Restore caller's signal mask 869 sigset_t sigmask = osthread->caller_sigmask(); 870 pthread_sigmask(SIG_SETMASK, &sigmask, NULL); 871 } 872 873 delete osthread; 874 } 875 876 ////////////////////////////////////////////////////////////////////////////// 877 // thread local storage 878 879 // Restore the thread pointer if the destructor is called. This is in case 880 // someone from JNI code sets up a destructor with pthread_key_create to run 881 // detachCurrentThread on thread death. Unless we restore the thread pointer we 882 // will hang or crash. When detachCurrentThread is called the key will be set 883 // to null and we will not be called again. If detachCurrentThread is never 884 // called we could loop forever depending on the pthread implementation. 885 static void restore_thread_pointer(void* p) { 886 Thread* thread = (Thread*) p; 887 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread); 888 } 889 890 int os::allocate_thread_local_storage() { 891 pthread_key_t key; 892 int rslt = pthread_key_create(&key, restore_thread_pointer); 893 assert(rslt == 0, "cannot allocate thread local storage"); 894 return (int)key; 895 } 896 897 // Note: This is currently not used by VM, as we don't destroy TLS key 898 // on VM exit. 899 void os::free_thread_local_storage(int index) { 900 int rslt = pthread_key_delete((pthread_key_t)index); 901 assert(rslt == 0, "invalid index"); 902 } 903 904 void os::thread_local_storage_at_put(int index, void* value) { 905 int rslt = pthread_setspecific((pthread_key_t)index, value); 906 assert(rslt == 0, "pthread_setspecific failed"); 907 } 908 909 extern "C" Thread* get_thread() { 910 return ThreadLocalStorage::thread(); 911 } 912 913 ////////////////////////////////////////////////////////////////////////////// 914 // initial thread 915 916 // Check if current thread is the initial thread, similar to Solaris thr_main. 917 bool os::Linux::is_initial_thread(void) { 918 char dummy; 919 // If called before init complete, thread stack bottom will be null. 920 // Can be called if fatal error occurs before initialization. 921 if (initial_thread_stack_bottom() == NULL) return false; 922 assert(initial_thread_stack_bottom() != NULL && 923 initial_thread_stack_size() != 0, 924 "os::init did not locate initial thread's stack region"); 925 if ((address)&dummy >= initial_thread_stack_bottom() && 926 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) { 927 return true; 928 } else { 929 return false; 930 } 931 } 932 933 // Find the virtual memory area that contains addr 934 static bool find_vma(address addr, address* vma_low, address* vma_high) { 935 FILE *fp = fopen("/proc/self/maps", "r"); 936 if (fp) { 937 address low, high; 938 while (!feof(fp)) { 939 if (fscanf(fp, "%p-%p", &low, &high) == 2) { 940 if (low <= addr && addr < high) { 941 if (vma_low) *vma_low = low; 942 if (vma_high) *vma_high = high; 943 fclose(fp); 944 return true; 945 } 946 } 947 for (;;) { 948 int ch = fgetc(fp); 949 if (ch == EOF || ch == (int)'\n') break; 950 } 951 } 952 fclose(fp); 953 } 954 return false; 955 } 956 957 // Locate initial thread stack. This special handling of initial thread stack 958 // is needed because pthread_getattr_np() on most (all?) Linux distros returns 959 // bogus value for initial thread. 960 void os::Linux::capture_initial_stack(size_t max_size) { 961 // stack size is the easy part, get it from RLIMIT_STACK 962 size_t stack_size; 963 struct rlimit rlim; 964 getrlimit(RLIMIT_STACK, &rlim); 965 stack_size = rlim.rlim_cur; 966 967 // 6308388: a bug in ld.so will relocate its own .data section to the 968 // lower end of primordial stack; reduce ulimit -s value a little bit 969 // so we won't install guard page on ld.so's data section. 970 stack_size -= 2 * page_size(); 971 972 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat 973 // 7.1, in both cases we will get 2G in return value. 974 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0, 975 // SuSE 7.2, Debian) can not handle alternate signal stack correctly 976 // for initial thread if its stack size exceeds 6M. Cap it at 2M, 977 // in case other parts in glibc still assumes 2M max stack size. 978 // FIXME: alt signal stack is gone, maybe we can relax this constraint? 979 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small 980 if (stack_size > 2 * K * K IA64_ONLY(*2)) { 981 stack_size = 2 * K * K IA64_ONLY(*2); 982 } 983 // Try to figure out where the stack base (top) is. This is harder. 984 // 985 // When an application is started, glibc saves the initial stack pointer in 986 // a global variable "__libc_stack_end", which is then used by system 987 // libraries. __libc_stack_end should be pretty close to stack top. The 988 // variable is available since the very early days. However, because it is 989 // a private interface, it could disappear in the future. 990 // 991 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar 992 // to __libc_stack_end, it is very close to stack top, but isn't the real 993 // stack top. Note that /proc may not exist if VM is running as a chroot 994 // program, so reading /proc/<pid>/stat could fail. Also the contents of 995 // /proc/<pid>/stat could change in the future (though unlikely). 996 // 997 // We try __libc_stack_end first. If that doesn't work, look for 998 // /proc/<pid>/stat. If neither of them works, we use current stack pointer 999 // as a hint, which should work well in most cases. 1000 1001 uintptr_t stack_start; 1002 1003 // try __libc_stack_end first 1004 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end"); 1005 if (p && *p) { 1006 stack_start = *p; 1007 } else { 1008 // see if we can get the start_stack field from /proc/self/stat 1009 FILE *fp; 1010 int pid; 1011 char state; 1012 int ppid; 1013 int pgrp; 1014 int session; 1015 int nr; 1016 int tpgrp; 1017 unsigned long flags; 1018 unsigned long minflt; 1019 unsigned long cminflt; 1020 unsigned long majflt; 1021 unsigned long cmajflt; 1022 unsigned long utime; 1023 unsigned long stime; 1024 long cutime; 1025 long cstime; 1026 long prio; 1027 long nice; 1028 long junk; 1029 long it_real; 1030 uintptr_t start; 1031 uintptr_t vsize; 1032 intptr_t rss; 1033 uintptr_t rsslim; 1034 uintptr_t scodes; 1035 uintptr_t ecode; 1036 int i; 1037 1038 // Figure what the primordial thread stack base is. Code is inspired 1039 // by email from Hans Boehm. /proc/self/stat begins with current pid, 1040 // followed by command name surrounded by parentheses, state, etc. 1041 char stat[2048]; 1042 int statlen; 1043 1044 fp = fopen("/proc/self/stat", "r"); 1045 if (fp) { 1046 statlen = fread(stat, 1, 2047, fp); 1047 stat[statlen] = '\0'; 1048 fclose(fp); 1049 1050 // Skip pid and the command string. Note that we could be dealing with 1051 // weird command names, e.g. user could decide to rename java launcher 1052 // to "java 1.4.2 :)", then the stat file would look like 1053 // 1234 (java 1.4.2 :)) R ... ... 1054 // We don't really need to know the command string, just find the last 1055 // occurrence of ")" and then start parsing from there. See bug 4726580. 1056 char * s = strrchr(stat, ')'); 1057 1058 i = 0; 1059 if (s) { 1060 // Skip blank chars 1061 do { s++; } while (s && isspace(*s)); 1062 1063 #define _UFM UINTX_FORMAT 1064 #define _DFM INTX_FORMAT 1065 1066 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 1067 // 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 1068 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, 1069 &state, // 3 %c 1070 &ppid, // 4 %d 1071 &pgrp, // 5 %d 1072 &session, // 6 %d 1073 &nr, // 7 %d 1074 &tpgrp, // 8 %d 1075 &flags, // 9 %lu 1076 &minflt, // 10 %lu 1077 &cminflt, // 11 %lu 1078 &majflt, // 12 %lu 1079 &cmajflt, // 13 %lu 1080 &utime, // 14 %lu 1081 &stime, // 15 %lu 1082 &cutime, // 16 %ld 1083 &cstime, // 17 %ld 1084 &prio, // 18 %ld 1085 &nice, // 19 %ld 1086 &junk, // 20 %ld 1087 &it_real, // 21 %ld 1088 &start, // 22 UINTX_FORMAT 1089 &vsize, // 23 UINTX_FORMAT 1090 &rss, // 24 INTX_FORMAT 1091 &rsslim, // 25 UINTX_FORMAT 1092 &scodes, // 26 UINTX_FORMAT 1093 &ecode, // 27 UINTX_FORMAT 1094 &stack_start); // 28 UINTX_FORMAT 1095 } 1096 1097 #undef _UFM 1098 #undef _DFM 1099 1100 if (i != 28 - 2) { 1101 assert(false, "Bad conversion from /proc/self/stat"); 1102 // product mode - assume we are the initial thread, good luck in the 1103 // embedded case. 1104 warning("Can't detect initial thread stack location - bad conversion"); 1105 stack_start = (uintptr_t) &rlim; 1106 } 1107 } else { 1108 // For some reason we can't open /proc/self/stat (for example, running on 1109 // FreeBSD with a Linux emulator, or inside chroot), this should work for 1110 // most cases, so don't abort: 1111 warning("Can't detect initial thread stack location - no /proc/self/stat"); 1112 stack_start = (uintptr_t) &rlim; 1113 } 1114 } 1115 1116 // Now we have a pointer (stack_start) very close to the stack top, the 1117 // next thing to do is to figure out the exact location of stack top. We 1118 // can find out the virtual memory area that contains stack_start by 1119 // reading /proc/self/maps, it should be the last vma in /proc/self/maps, 1120 // and its upper limit is the real stack top. (again, this would fail if 1121 // running inside chroot, because /proc may not exist.) 1122 1123 uintptr_t stack_top; 1124 address low, high; 1125 if (find_vma((address)stack_start, &low, &high)) { 1126 // success, "high" is the true stack top. (ignore "low", because initial 1127 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.) 1128 stack_top = (uintptr_t)high; 1129 } else { 1130 // failed, likely because /proc/self/maps does not exist 1131 warning("Can't detect initial thread stack location - find_vma failed"); 1132 // best effort: stack_start is normally within a few pages below the real 1133 // stack top, use it as stack top, and reduce stack size so we won't put 1134 // guard page outside stack. 1135 stack_top = stack_start; 1136 stack_size -= 16 * page_size(); 1137 } 1138 1139 // stack_top could be partially down the page so align it 1140 stack_top = align_size_up(stack_top, page_size()); 1141 1142 if (max_size && stack_size > max_size) { 1143 _initial_thread_stack_size = max_size; 1144 } else { 1145 _initial_thread_stack_size = stack_size; 1146 } 1147 1148 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size()); 1149 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size; 1150 } 1151 1152 //////////////////////////////////////////////////////////////////////////////// 1153 // time support 1154 1155 // Time since start-up in seconds to a fine granularity. 1156 // Used by VMSelfDestructTimer and the MemProfiler. 1157 double os::elapsedTime() { 1158 1159 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution 1160 } 1161 1162 jlong os::elapsed_counter() { 1163 return javaTimeNanos() - initial_time_count; 1164 } 1165 1166 jlong os::elapsed_frequency() { 1167 return NANOSECS_PER_SEC; // nanosecond resolution 1168 } 1169 1170 bool os::supports_vtime() { return true; } 1171 bool os::enable_vtime() { return false; } 1172 bool os::vtime_enabled() { return false; } 1173 1174 double os::elapsedVTime() { 1175 struct rusage usage; 1176 int retval = getrusage(RUSAGE_THREAD, &usage); 1177 if (retval == 0) { 1178 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); 1179 } else { 1180 // better than nothing, but not much 1181 return elapsedTime(); 1182 } 1183 } 1184 1185 jlong os::javaTimeMillis() { 1186 timeval time; 1187 int status = gettimeofday(&time, NULL); 1188 assert(status != -1, "linux error"); 1189 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000); 1190 } 1191 1192 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) { 1193 timeval time; 1194 int status = gettimeofday(&time, NULL); 1195 assert(status != -1, "linux error"); 1196 seconds = jlong(time.tv_sec); 1197 nanos = jlong(time.tv_usec) * 1000; 1198 } 1199 1200 1201 #ifndef CLOCK_MONOTONIC 1202 #define CLOCK_MONOTONIC (1) 1203 #endif 1204 1205 void os::Linux::clock_init() { 1206 // we do dlopen's in this particular order due to bug in linux 1207 // dynamical loader (see 6348968) leading to crash on exit 1208 void* handle = dlopen("librt.so.1", RTLD_LAZY); 1209 if (handle == NULL) { 1210 handle = dlopen("librt.so", RTLD_LAZY); 1211 } 1212 1213 if (handle) { 1214 int (*clock_getres_func)(clockid_t, struct timespec*) = 1215 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres"); 1216 int (*clock_gettime_func)(clockid_t, struct timespec*) = 1217 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime"); 1218 if (clock_getres_func && clock_gettime_func) { 1219 // See if monotonic clock is supported by the kernel. Note that some 1220 // early implementations simply return kernel jiffies (updated every 1221 // 1/100 or 1/1000 second). It would be bad to use such a low res clock 1222 // for nano time (though the monotonic property is still nice to have). 1223 // It's fixed in newer kernels, however clock_getres() still returns 1224 // 1/HZ. We check if clock_getres() works, but will ignore its reported 1225 // resolution for now. Hopefully as people move to new kernels, this 1226 // won't be a problem. 1227 struct timespec res; 1228 struct timespec tp; 1229 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 && 1230 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) { 1231 // yes, monotonic clock is supported 1232 _clock_gettime = clock_gettime_func; 1233 return; 1234 } else { 1235 // close librt if there is no monotonic clock 1236 dlclose(handle); 1237 } 1238 } 1239 } 1240 warning("No monotonic clock was available - timed services may " \ 1241 "be adversely affected if the time-of-day clock changes"); 1242 } 1243 1244 #ifndef SYS_clock_getres 1245 #if defined(IA32) || defined(AMD64) 1246 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) 1247 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1248 #else 1249 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time" 1250 #define sys_clock_getres(x,y) -1 1251 #endif 1252 #else 1253 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y) 1254 #endif 1255 1256 void os::Linux::fast_thread_clock_init() { 1257 if (!UseLinuxPosixThreadCPUClocks) { 1258 return; 1259 } 1260 clockid_t clockid; 1261 struct timespec tp; 1262 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) = 1263 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid"); 1264 1265 // Switch to using fast clocks for thread cpu time if 1266 // the sys_clock_getres() returns 0 error code. 1267 // Note, that some kernels may support the current thread 1268 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks 1269 // returned by the pthread_getcpuclockid(). 1270 // If the fast Posix clocks are supported then the sys_clock_getres() 1271 // must return at least tp.tv_sec == 0 which means a resolution 1272 // better than 1 sec. This is extra check for reliability. 1273 1274 if (pthread_getcpuclockid_func && 1275 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 && 1276 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) { 1277 _supports_fast_thread_cpu_time = true; 1278 _pthread_getcpuclockid = pthread_getcpuclockid_func; 1279 } 1280 } 1281 1282 jlong os::javaTimeNanos() { 1283 if (os::supports_monotonic_clock()) { 1284 struct timespec tp; 1285 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp); 1286 assert(status == 0, "gettime error"); 1287 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec); 1288 return result; 1289 } else { 1290 timeval time; 1291 int status = gettimeofday(&time, NULL); 1292 assert(status != -1, "linux error"); 1293 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec); 1294 return 1000 * usecs; 1295 } 1296 } 1297 1298 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) { 1299 if (os::supports_monotonic_clock()) { 1300 info_ptr->max_value = ALL_64_BITS; 1301 1302 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past 1303 info_ptr->may_skip_backward = false; // not subject to resetting or drifting 1304 info_ptr->may_skip_forward = false; // not subject to resetting or drifting 1305 } else { 1306 // gettimeofday - based on time in seconds since the Epoch thus does not wrap 1307 info_ptr->max_value = ALL_64_BITS; 1308 1309 // gettimeofday is a real time clock so it skips 1310 info_ptr->may_skip_backward = true; 1311 info_ptr->may_skip_forward = true; 1312 } 1313 1314 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time 1315 } 1316 1317 // Return the real, user, and system times in seconds from an 1318 // arbitrary fixed point in the past. 1319 bool os::getTimesSecs(double* process_real_time, 1320 double* process_user_time, 1321 double* process_system_time) { 1322 struct tms ticks; 1323 clock_t real_ticks = times(&ticks); 1324 1325 if (real_ticks == (clock_t) (-1)) { 1326 return false; 1327 } else { 1328 double ticks_per_second = (double) clock_tics_per_sec; 1329 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second; 1330 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second; 1331 *process_real_time = ((double) real_ticks) / ticks_per_second; 1332 1333 return true; 1334 } 1335 } 1336 1337 1338 char * os::local_time_string(char *buf, size_t buflen) { 1339 struct tm t; 1340 time_t long_time; 1341 time(&long_time); 1342 localtime_r(&long_time, &t); 1343 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d", 1344 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, 1345 t.tm_hour, t.tm_min, t.tm_sec); 1346 return buf; 1347 } 1348 1349 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) { 1350 return localtime_r(clock, res); 1351 } 1352 1353 //////////////////////////////////////////////////////////////////////////////// 1354 // runtime exit support 1355 1356 // Note: os::shutdown() might be called very early during initialization, or 1357 // called from signal handler. Before adding something to os::shutdown(), make 1358 // sure it is async-safe and can handle partially initialized VM. 1359 void os::shutdown() { 1360 1361 // allow PerfMemory to attempt cleanup of any persistent resources 1362 perfMemory_exit(); 1363 1364 // needs to remove object in file system 1365 AttachListener::abort(); 1366 1367 // flush buffered output, finish log files 1368 ostream_abort(); 1369 1370 // Check for abort hook 1371 abort_hook_t abort_hook = Arguments::abort_hook(); 1372 if (abort_hook != NULL) { 1373 abort_hook(); 1374 } 1375 1376 } 1377 1378 // Note: os::abort() might be called very early during initialization, or 1379 // called from signal handler. Before adding something to os::abort(), make 1380 // sure it is async-safe and can handle partially initialized VM. 1381 void os::abort(bool dump_core, void* siginfo, void* context) { 1382 os::shutdown(); 1383 if (dump_core) { 1384 #ifndef PRODUCT 1385 fdStream out(defaultStream::output_fd()); 1386 out.print_raw("Current thread is "); 1387 char buf[16]; 1388 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id()); 1389 out.print_raw_cr(buf); 1390 out.print_raw_cr("Dumping core ..."); 1391 #endif 1392 ::abort(); // dump core 1393 } 1394 1395 ::exit(1); 1396 } 1397 1398 // Die immediately, no exit hook, no abort hook, no cleanup. 1399 void os::die() { 1400 ::abort(); 1401 } 1402 1403 1404 // This method is a copy of JDK's sysGetLastErrorString 1405 // from src/solaris/hpi/src/system_md.c 1406 1407 size_t os::lasterror(char *buf, size_t len) { 1408 if (errno == 0) return 0; 1409 1410 const char *s = ::strerror(errno); 1411 size_t n = ::strlen(s); 1412 if (n >= len) { 1413 n = len - 1; 1414 } 1415 ::strncpy(buf, s, n); 1416 buf[n] = '\0'; 1417 return n; 1418 } 1419 1420 // thread_id is kernel thread id (similar to Solaris LWP id) 1421 intx os::current_thread_id() { return os::Linux::gettid(); } 1422 int os::current_process_id() { 1423 return ::getpid(); 1424 } 1425 1426 // DLL functions 1427 1428 const char* os::dll_file_extension() { return ".so"; } 1429 1430 // This must be hard coded because it's the system's temporary 1431 // directory not the java application's temp directory, ala java.io.tmpdir. 1432 const char* os::get_temp_directory() { return "/tmp"; } 1433 1434 static bool file_exists(const char* filename) { 1435 struct stat statbuf; 1436 if (filename == NULL || strlen(filename) == 0) { 1437 return false; 1438 } 1439 return os::stat(filename, &statbuf) == 0; 1440 } 1441 1442 bool os::dll_build_name(char* buffer, size_t buflen, 1443 const char* pname, const char* fname) { 1444 bool retval = false; 1445 // Copied from libhpi 1446 const size_t pnamelen = pname ? strlen(pname) : 0; 1447 1448 // Return error on buffer overflow. 1449 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) { 1450 return retval; 1451 } 1452 1453 if (pnamelen == 0) { 1454 snprintf(buffer, buflen, "lib%s.so", fname); 1455 retval = true; 1456 } else if (strchr(pname, *os::path_separator()) != NULL) { 1457 int n; 1458 char** pelements = split_path(pname, &n); 1459 if (pelements == NULL) { 1460 return false; 1461 } 1462 for (int i = 0; i < n; i++) { 1463 // Really shouldn't be NULL, but check can't hurt 1464 if (pelements[i] == NULL || strlen(pelements[i]) == 0) { 1465 continue; // skip the empty path values 1466 } 1467 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname); 1468 if (file_exists(buffer)) { 1469 retval = true; 1470 break; 1471 } 1472 } 1473 // release the storage 1474 for (int i = 0; i < n; i++) { 1475 if (pelements[i] != NULL) { 1476 FREE_C_HEAP_ARRAY(char, pelements[i]); 1477 } 1478 } 1479 if (pelements != NULL) { 1480 FREE_C_HEAP_ARRAY(char*, pelements); 1481 } 1482 } else { 1483 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname); 1484 retval = true; 1485 } 1486 return retval; 1487 } 1488 1489 // check if addr is inside libjvm.so 1490 bool os::address_is_in_vm(address addr) { 1491 static address libjvm_base_addr; 1492 Dl_info dlinfo; 1493 1494 if (libjvm_base_addr == NULL) { 1495 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) { 1496 libjvm_base_addr = (address)dlinfo.dli_fbase; 1497 } 1498 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm"); 1499 } 1500 1501 if (dladdr((void *)addr, &dlinfo) != 0) { 1502 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true; 1503 } 1504 1505 return false; 1506 } 1507 1508 bool os::dll_address_to_function_name(address addr, char *buf, 1509 int buflen, int *offset, 1510 bool demangle) { 1511 // buf is not optional, but offset is optional 1512 assert(buf != NULL, "sanity check"); 1513 1514 Dl_info dlinfo; 1515 1516 if (dladdr((void*)addr, &dlinfo) != 0) { 1517 // see if we have a matching symbol 1518 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) { 1519 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) { 1520 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname); 1521 } 1522 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr; 1523 return true; 1524 } 1525 // no matching symbol so try for just file info 1526 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) { 1527 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase), 1528 buf, buflen, offset, dlinfo.dli_fname, demangle)) { 1529 return true; 1530 } 1531 } 1532 } 1533 1534 buf[0] = '\0'; 1535 if (offset != NULL) *offset = -1; 1536 return false; 1537 } 1538 1539 struct _address_to_library_name { 1540 address addr; // input : memory address 1541 size_t buflen; // size of fname 1542 char* fname; // output: library name 1543 address base; // library base addr 1544 }; 1545 1546 static int address_to_library_name_callback(struct dl_phdr_info *info, 1547 size_t size, void *data) { 1548 int i; 1549 bool found = false; 1550 address libbase = NULL; 1551 struct _address_to_library_name * d = (struct _address_to_library_name *)data; 1552 1553 // iterate through all loadable segments 1554 for (i = 0; i < info->dlpi_phnum; i++) { 1555 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr); 1556 if (info->dlpi_phdr[i].p_type == PT_LOAD) { 1557 // base address of a library is the lowest address of its loaded 1558 // segments. 1559 if (libbase == NULL || libbase > segbase) { 1560 libbase = segbase; 1561 } 1562 // see if 'addr' is within current segment 1563 if (segbase <= d->addr && 1564 d->addr < segbase + info->dlpi_phdr[i].p_memsz) { 1565 found = true; 1566 } 1567 } 1568 } 1569 1570 // dlpi_name is NULL or empty if the ELF file is executable, return 0 1571 // so dll_address_to_library_name() can fall through to use dladdr() which 1572 // can figure out executable name from argv[0]. 1573 if (found && info->dlpi_name && info->dlpi_name[0]) { 1574 d->base = libbase; 1575 if (d->fname) { 1576 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name); 1577 } 1578 return 1; 1579 } 1580 return 0; 1581 } 1582 1583 bool os::dll_address_to_library_name(address addr, char* buf, 1584 int buflen, int* offset) { 1585 // buf is not optional, but offset is optional 1586 assert(buf != NULL, "sanity check"); 1587 1588 Dl_info dlinfo; 1589 struct _address_to_library_name data; 1590 1591 // There is a bug in old glibc dladdr() implementation that it could resolve 1592 // to wrong library name if the .so file has a base address != NULL. Here 1593 // we iterate through the program headers of all loaded libraries to find 1594 // out which library 'addr' really belongs to. This workaround can be 1595 // removed once the minimum requirement for glibc is moved to 2.3.x. 1596 data.addr = addr; 1597 data.fname = buf; 1598 data.buflen = buflen; 1599 data.base = NULL; 1600 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data); 1601 1602 if (rslt) { 1603 // buf already contains library name 1604 if (offset) *offset = addr - data.base; 1605 return true; 1606 } 1607 if (dladdr((void*)addr, &dlinfo) != 0) { 1608 if (dlinfo.dli_fname != NULL) { 1609 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname); 1610 } 1611 if (dlinfo.dli_fbase != NULL && offset != NULL) { 1612 *offset = addr - (address)dlinfo.dli_fbase; 1613 } 1614 return true; 1615 } 1616 1617 buf[0] = '\0'; 1618 if (offset) *offset = -1; 1619 return false; 1620 } 1621 1622 // Loads .dll/.so and 1623 // in case of error it checks if .dll/.so was built for the 1624 // same architecture as Hotspot is running on 1625 1626 1627 // Remember the stack's state. The Linux dynamic linker will change 1628 // the stack to 'executable' at most once, so we must safepoint only once. 1629 bool os::Linux::_stack_is_executable = false; 1630 1631 // VM operation that loads a library. This is necessary if stack protection 1632 // of the Java stacks can be lost during loading the library. If we 1633 // do not stop the Java threads, they can stack overflow before the stacks 1634 // are protected again. 1635 class VM_LinuxDllLoad: public VM_Operation { 1636 private: 1637 const char *_filename; 1638 char *_ebuf; 1639 int _ebuflen; 1640 void *_lib; 1641 public: 1642 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) : 1643 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {} 1644 VMOp_Type type() const { return VMOp_LinuxDllLoad; } 1645 void doit() { 1646 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen); 1647 os::Linux::_stack_is_executable = true; 1648 } 1649 void* loaded_library() { return _lib; } 1650 }; 1651 1652 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) { 1653 void * result = NULL; 1654 bool load_attempted = false; 1655 1656 // Check whether the library to load might change execution rights 1657 // of the stack. If they are changed, the protection of the stack 1658 // guard pages will be lost. We need a safepoint to fix this. 1659 // 1660 // See Linux man page execstack(8) for more info. 1661 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) { 1662 ElfFile ef(filename); 1663 if (!ef.specifies_noexecstack()) { 1664 if (!is_init_completed()) { 1665 os::Linux::_stack_is_executable = true; 1666 // This is OK - No Java threads have been created yet, and hence no 1667 // stack guard pages to fix. 1668 // 1669 // This should happen only when you are building JDK7 using a very 1670 // old version of JDK6 (e.g., with JPRT) and running test_gamma. 1671 // 1672 // Dynamic loader will make all stacks executable after 1673 // this function returns, and will not do that again. 1674 assert(Threads::first() == NULL, "no Java threads should exist yet."); 1675 } else { 1676 warning("You have loaded library %s which might have disabled stack guard. " 1677 "The VM will try to fix the stack guard now.\n" 1678 "It's highly recommended that you fix the library with " 1679 "'execstack -c <libfile>', or link it with '-z noexecstack'.", 1680 filename); 1681 1682 assert(Thread::current()->is_Java_thread(), "must be Java thread"); 1683 JavaThread *jt = JavaThread::current(); 1684 if (jt->thread_state() != _thread_in_native) { 1685 // This happens when a compiler thread tries to load a hsdis-<arch>.so file 1686 // that requires ExecStack. Cannot enter safe point. Let's give up. 1687 warning("Unable to fix stack guard. Giving up."); 1688 } else { 1689 if (!LoadExecStackDllInVMThread) { 1690 // This is for the case where the DLL has an static 1691 // constructor function that executes JNI code. We cannot 1692 // load such DLLs in the VMThread. 1693 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1694 } 1695 1696 ThreadInVMfromNative tiv(jt); 1697 debug_only(VMNativeEntryWrapper vew;) 1698 1699 VM_LinuxDllLoad op(filename, ebuf, ebuflen); 1700 VMThread::execute(&op); 1701 if (LoadExecStackDllInVMThread) { 1702 result = op.loaded_library(); 1703 } 1704 load_attempted = true; 1705 } 1706 } 1707 } 1708 } 1709 1710 if (!load_attempted) { 1711 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen); 1712 } 1713 1714 if (result != NULL) { 1715 // Successful loading 1716 return result; 1717 } 1718 1719 Elf32_Ehdr elf_head; 1720 int diag_msg_max_length=ebuflen-strlen(ebuf); 1721 char* diag_msg_buf=ebuf+strlen(ebuf); 1722 1723 if (diag_msg_max_length==0) { 1724 // No more space in ebuf for additional diagnostics message 1725 return NULL; 1726 } 1727 1728 1729 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK); 1730 1731 if (file_descriptor < 0) { 1732 // Can't open library, report dlerror() message 1733 return NULL; 1734 } 1735 1736 bool failed_to_read_elf_head= 1737 (sizeof(elf_head)!= 1738 (::read(file_descriptor, &elf_head,sizeof(elf_head)))); 1739 1740 ::close(file_descriptor); 1741 if (failed_to_read_elf_head) { 1742 // file i/o error - report dlerror() msg 1743 return NULL; 1744 } 1745 1746 typedef struct { 1747 Elf32_Half code; // Actual value as defined in elf.h 1748 Elf32_Half compat_class; // Compatibility of archs at VM's sense 1749 char elf_class; // 32 or 64 bit 1750 char endianess; // MSB or LSB 1751 char* name; // String representation 1752 } arch_t; 1753 1754 #ifndef EM_486 1755 #define EM_486 6 /* Intel 80486 */ 1756 #endif 1757 #ifndef EM_AARCH64 1758 #define EM_AARCH64 183 /* ARM AARCH64 */ 1759 #endif 1760 1761 static const arch_t arch_array[]={ 1762 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1763 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"}, 1764 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"}, 1765 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"}, 1766 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1767 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"}, 1768 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"}, 1769 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"}, 1770 #if defined(VM_LITTLE_ENDIAN) 1771 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"}, 1772 #else 1773 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}, 1774 #endif 1775 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"}, 1776 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"}, 1777 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"}, 1778 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"}, 1779 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"}, 1780 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"}, 1781 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}, 1782 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"}, 1783 }; 1784 1785 #if (defined IA32) 1786 static Elf32_Half running_arch_code=EM_386; 1787 #elif (defined AMD64) 1788 static Elf32_Half running_arch_code=EM_X86_64; 1789 #elif (defined IA64) 1790 static Elf32_Half running_arch_code=EM_IA_64; 1791 #elif (defined __sparc) && (defined _LP64) 1792 static Elf32_Half running_arch_code=EM_SPARCV9; 1793 #elif (defined __sparc) && (!defined _LP64) 1794 static Elf32_Half running_arch_code=EM_SPARC; 1795 #elif (defined __powerpc64__) 1796 static Elf32_Half running_arch_code=EM_PPC64; 1797 #elif (defined __powerpc__) 1798 static Elf32_Half running_arch_code=EM_PPC; 1799 #elif (defined ARM) 1800 static Elf32_Half running_arch_code=EM_ARM; 1801 #elif (defined S390) 1802 static Elf32_Half running_arch_code=EM_S390; 1803 #elif (defined ALPHA) 1804 static Elf32_Half running_arch_code=EM_ALPHA; 1805 #elif (defined MIPSEL) 1806 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE; 1807 #elif (defined PARISC) 1808 static Elf32_Half running_arch_code=EM_PARISC; 1809 #elif (defined MIPS) 1810 static Elf32_Half running_arch_code=EM_MIPS; 1811 #elif (defined M68K) 1812 static Elf32_Half running_arch_code=EM_68K; 1813 #elif (defined AARCH64) 1814 static Elf32_Half running_arch_code=EM_AARCH64; 1815 #else 1816 #error Method os::dll_load requires that one of following is defined:\ 1817 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64 1818 #endif 1819 1820 // Identify compatability class for VM's architecture and library's architecture 1821 // Obtain string descriptions for architectures 1822 1823 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL}; 1824 int running_arch_index=-1; 1825 1826 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) { 1827 if (running_arch_code == arch_array[i].code) { 1828 running_arch_index = i; 1829 } 1830 if (lib_arch.code == arch_array[i].code) { 1831 lib_arch.compat_class = arch_array[i].compat_class; 1832 lib_arch.name = arch_array[i].name; 1833 } 1834 } 1835 1836 assert(running_arch_index != -1, 1837 "Didn't find running architecture code (running_arch_code) in arch_array"); 1838 if (running_arch_index == -1) { 1839 // Even though running architecture detection failed 1840 // we may still continue with reporting dlerror() message 1841 return NULL; 1842 } 1843 1844 if (lib_arch.endianess != arch_array[running_arch_index].endianess) { 1845 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)"); 1846 return NULL; 1847 } 1848 1849 #ifndef S390 1850 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) { 1851 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)"); 1852 return NULL; 1853 } 1854 #endif // !S390 1855 1856 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) { 1857 if (lib_arch.name!=NULL) { 1858 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1859 " (Possible cause: can't load %s-bit .so on a %s-bit platform)", 1860 lib_arch.name, arch_array[running_arch_index].name); 1861 } else { 1862 ::snprintf(diag_msg_buf, diag_msg_max_length-1, 1863 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)", 1864 lib_arch.code, 1865 arch_array[running_arch_index].name); 1866 } 1867 } 1868 1869 return NULL; 1870 } 1871 1872 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, 1873 int ebuflen) { 1874 void * result = ::dlopen(filename, RTLD_LAZY); 1875 if (result == NULL) { 1876 ::strncpy(ebuf, ::dlerror(), ebuflen - 1); 1877 ebuf[ebuflen-1] = '\0'; 1878 } 1879 return result; 1880 } 1881 1882 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, 1883 int ebuflen) { 1884 void * result = NULL; 1885 if (LoadExecStackDllInVMThread) { 1886 result = dlopen_helper(filename, ebuf, ebuflen); 1887 } 1888 1889 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a 1890 // library that requires an executable stack, or which does not have this 1891 // stack attribute set, dlopen changes the stack attribute to executable. The 1892 // read protection of the guard pages gets lost. 1893 // 1894 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad 1895 // may have been queued at the same time. 1896 1897 if (!_stack_is_executable) { 1898 JavaThread *jt = Threads::first(); 1899 1900 while (jt) { 1901 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized 1902 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions 1903 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(), 1904 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) { 1905 warning("Attempt to reguard stack yellow zone failed."); 1906 } 1907 } 1908 jt = jt->next(); 1909 } 1910 } 1911 1912 return result; 1913 } 1914 1915 void* os::dll_lookup(void* handle, const char* name) { 1916 void* res = dlsym(handle, name); 1917 return res; 1918 } 1919 1920 void* os::get_default_process_handle() { 1921 return (void*)::dlopen(NULL, RTLD_LAZY); 1922 } 1923 1924 static bool _print_ascii_file(const char* filename, outputStream* st) { 1925 int fd = ::open(filename, O_RDONLY); 1926 if (fd == -1) { 1927 return false; 1928 } 1929 1930 char buf[32]; 1931 int bytes; 1932 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) { 1933 st->print_raw(buf, bytes); 1934 } 1935 1936 ::close(fd); 1937 1938 return true; 1939 } 1940 1941 void os::print_dll_info(outputStream *st) { 1942 st->print_cr("Dynamic libraries:"); 1943 1944 char fname[32]; 1945 pid_t pid = os::Linux::gettid(); 1946 1947 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid); 1948 1949 if (!_print_ascii_file(fname, st)) { 1950 st->print("Can not get library information for pid = %d\n", pid); 1951 } 1952 } 1953 1954 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) { 1955 FILE *procmapsFile = NULL; 1956 1957 // Open the procfs maps file for the current process 1958 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) { 1959 // Allocate PATH_MAX for file name plus a reasonable size for other fields. 1960 char line[PATH_MAX + 100]; 1961 1962 // Read line by line from 'file' 1963 while (fgets(line, sizeof(line), procmapsFile) != NULL) { 1964 u8 base, top, offset, inode; 1965 char permissions[5]; 1966 char device[6]; 1967 char name[PATH_MAX + 1]; 1968 1969 // Parse fields from line 1970 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s", 1971 &base, &top, permissions, &offset, device, &inode, name); 1972 1973 // Filter by device id '00:00' so that we only get file system mapped files. 1974 if (strcmp(device, "00:00") != 0) { 1975 1976 // Call callback with the fields of interest 1977 if(callback(name, (address)base, (address)top, param)) { 1978 // Oops abort, callback aborted 1979 fclose(procmapsFile); 1980 return 1; 1981 } 1982 } 1983 } 1984 fclose(procmapsFile); 1985 } 1986 return 0; 1987 } 1988 1989 void os::print_os_info_brief(outputStream* st) { 1990 os::Linux::print_distro_info(st); 1991 1992 os::Posix::print_uname_info(st); 1993 1994 os::Linux::print_libversion_info(st); 1995 1996 } 1997 1998 void os::print_os_info(outputStream* st) { 1999 st->print("OS:"); 2000 2001 os::Linux::print_distro_info(st); 2002 2003 os::Posix::print_uname_info(st); 2004 2005 // Print warning if unsafe chroot environment detected 2006 if (unsafe_chroot_detected) { 2007 st->print("WARNING!! "); 2008 st->print_cr("%s", unstable_chroot_error); 2009 } 2010 2011 os::Linux::print_libversion_info(st); 2012 2013 os::Posix::print_rlimit_info(st); 2014 2015 os::Posix::print_load_average(st); 2016 2017 os::Linux::print_full_memory_info(st); 2018 } 2019 2020 // Try to identify popular distros. 2021 // Most Linux distributions have a /etc/XXX-release file, which contains 2022 // the OS version string. Newer Linux distributions have a /etc/lsb-release 2023 // file that also contains the OS version string. Some have more than one 2024 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and 2025 // /etc/redhat-release.), so the order is important. 2026 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have 2027 // their own specific XXX-release file as well as a redhat-release file. 2028 // Because of this the XXX-release file needs to be searched for before the 2029 // redhat-release file. 2030 // Since Red Hat has a lsb-release file that is not very descriptive the 2031 // search for redhat-release needs to be before lsb-release. 2032 // Since the lsb-release file is the new standard it needs to be searched 2033 // before the older style release files. 2034 // Searching system-release (Red Hat) and os-release (other Linuxes) are a 2035 // next to last resort. The os-release file is a new standard that contains 2036 // distribution information and the system-release file seems to be an old 2037 // standard that has been replaced by the lsb-release and os-release files. 2038 // Searching for the debian_version file is the last resort. It contains 2039 // an informative string like "6.0.6" or "wheezy/sid". Because of this 2040 // "Debian " is printed before the contents of the debian_version file. 2041 2042 const char* distro_files[] = { 2043 "/etc/oracle-release", 2044 "/etc/mandriva-release", 2045 "/etc/mandrake-release", 2046 "/etc/sun-release", 2047 "/etc/redhat-release", 2048 "/etc/lsb-release", 2049 "/etc/SuSE-release", 2050 "/etc/turbolinux-release", 2051 "/etc/gentoo-release", 2052 "/etc/ltib-release", 2053 "/etc/angstrom-version", 2054 "/etc/system-release", 2055 "/etc/os-release", 2056 NULL }; 2057 2058 void os::Linux::print_distro_info(outputStream* st) { 2059 for (int i = 0;; i++) { 2060 const char* file = distro_files[i]; 2061 if (file == NULL) { 2062 break; // done 2063 } 2064 // If file prints, we found it. 2065 if (_print_ascii_file(file, st)) { 2066 return; 2067 } 2068 } 2069 2070 if (file_exists("/etc/debian_version")) { 2071 st->print("Debian "); 2072 _print_ascii_file("/etc/debian_version", st); 2073 } else { 2074 st->print("Linux"); 2075 } 2076 st->cr(); 2077 } 2078 2079 static void parse_os_info(char* distro, size_t length, const char* file) { 2080 FILE* fp = fopen(file, "r"); 2081 if (fp != NULL) { 2082 char buf[256]; 2083 // get last line of the file. 2084 while (fgets(buf, sizeof(buf), fp)) { } 2085 // Edit out extra stuff in expected ubuntu format 2086 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) { 2087 char* ptr = strstr(buf, "\""); // the name is in quotes 2088 if (ptr != NULL) { 2089 ptr++; // go beyond first quote 2090 char* nl = strchr(ptr, '\"'); 2091 if (nl != NULL) *nl = '\0'; 2092 strncpy(distro, ptr, length); 2093 } else { 2094 ptr = strstr(buf, "="); 2095 ptr++; // go beyond equals then 2096 char* nl = strchr(ptr, '\n'); 2097 if (nl != NULL) *nl = '\0'; 2098 strncpy(distro, ptr, length); 2099 } 2100 } else { 2101 // if not in expected Ubuntu format, print out whole line minus \n 2102 char* nl = strchr(buf, '\n'); 2103 if (nl != NULL) *nl = '\0'; 2104 strncpy(distro, buf, length); 2105 } 2106 // close distro file 2107 fclose(fp); 2108 } 2109 } 2110 2111 void os::get_summary_os_info(char* buf, size_t buflen) { 2112 for (int i = 0;; i++) { 2113 const char* file = distro_files[i]; 2114 if (file == NULL) { 2115 break; // ran out of distro_files 2116 } 2117 if (file_exists(file)) { 2118 parse_os_info(buf, buflen, file); 2119 return; 2120 } 2121 } 2122 // special case for debian 2123 if (file_exists("/etc/debian_version")) { 2124 strncpy(buf, "Debian ", buflen); 2125 parse_os_info(&buf[7], buflen-7, "/etc/debian_version"); 2126 } else { 2127 strncpy(buf, "Linux", buflen); 2128 } 2129 } 2130 2131 void os::Linux::print_libversion_info(outputStream* st) { 2132 // libc, pthread 2133 st->print("libc:"); 2134 st->print("%s ", os::Linux::glibc_version()); 2135 st->print("%s ", os::Linux::libpthread_version()); 2136 st->cr(); 2137 } 2138 2139 void os::Linux::print_full_memory_info(outputStream* st) { 2140 st->print("\n/proc/meminfo:\n"); 2141 _print_ascii_file("/proc/meminfo", st); 2142 st->cr(); 2143 } 2144 2145 void os::print_memory_info(outputStream* st) { 2146 2147 st->print("Memory:"); 2148 st->print(" %dk page", os::vm_page_size()>>10); 2149 2150 // values in struct sysinfo are "unsigned long" 2151 struct sysinfo si; 2152 sysinfo(&si); 2153 2154 st->print(", physical " UINT64_FORMAT "k", 2155 os::physical_memory() >> 10); 2156 st->print("(" UINT64_FORMAT "k free)", 2157 os::available_memory() >> 10); 2158 st->print(", swap " UINT64_FORMAT "k", 2159 ((jlong)si.totalswap * si.mem_unit) >> 10); 2160 st->print("(" UINT64_FORMAT "k free)", 2161 ((jlong)si.freeswap * si.mem_unit) >> 10); 2162 st->cr(); 2163 } 2164 2165 // Print the first "model name" line and the first "flags" line 2166 // that we find and nothing more. We assume "model name" comes 2167 // before "flags" so if we find a second "model name", then the 2168 // "flags" field is considered missing. 2169 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) { 2170 #if defined(IA32) || defined(AMD64) 2171 // Other platforms have less repetitive cpuinfo files 2172 FILE *fp = fopen("/proc/cpuinfo", "r"); 2173 if (fp) { 2174 while (!feof(fp)) { 2175 if (fgets(buf, buflen, fp)) { 2176 // Assume model name comes before flags 2177 bool model_name_printed = false; 2178 if (strstr(buf, "model name") != NULL) { 2179 if (!model_name_printed) { 2180 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n"); 2181 st->print_raw(buf); 2182 model_name_printed = true; 2183 } else { 2184 // model name printed but not flags? Odd, just return 2185 fclose(fp); 2186 return true; 2187 } 2188 } 2189 // print the flags line too 2190 if (strstr(buf, "flags") != NULL) { 2191 st->print_raw(buf); 2192 fclose(fp); 2193 return true; 2194 } 2195 } 2196 } 2197 fclose(fp); 2198 } 2199 #endif // x86 platforms 2200 return false; 2201 } 2202 2203 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) { 2204 // Only print the model name if the platform provides this as a summary 2205 if (!print_model_name_and_flags(st, buf, buflen)) { 2206 st->print("\n/proc/cpuinfo:\n"); 2207 if (!_print_ascii_file("/proc/cpuinfo", st)) { 2208 st->print_cr(" <Not Available>"); 2209 } 2210 } 2211 } 2212 2213 #if defined(AMD64) || defined(IA32) || defined(X32) 2214 const char* search_string = "model name"; 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(AMD64) 2255 strncpy(cpuinfo, "x86_64", length); 2256 #elif defined(IA32) 2257 strncpy(cpuinfo, "x86_32", length); 2258 #elif defined(IA64) 2259 strncpy(cpuinfo, "IA64", length); 2260 #elif defined(SPARC) 2261 strncpy(cpuinfo, "sparcv9", length); 2262 #elif defined(AARCH64) 2263 strncpy(cpuinfo, "AArch64", length); 2264 #elif defined(ARM) 2265 strncpy(cpuinfo, "ARM", length); 2266 #elif defined(PPC) 2267 strncpy(cpuinfo, "PPC64", length); 2268 #elif defined(ZERO_LIBARCH) 2269 strncpy(cpuinfo, ZERO_LIBARCH, length); 2270 #else 2271 strncpy(cpuinfo, "unknown", length); 2272 #endif 2273 } 2274 2275 void os::print_siginfo(outputStream* st, void* siginfo) { 2276 const siginfo_t* si = (const siginfo_t*)siginfo; 2277 2278 os::Posix::print_siginfo_brief(st, si); 2279 #if INCLUDE_CDS 2280 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) && 2281 UseSharedSpaces) { 2282 FileMapInfo* mapinfo = FileMapInfo::current_info(); 2283 if (mapinfo->is_in_shared_space(si->si_addr)) { 2284 st->print("\n\nError accessing class data sharing archive." \ 2285 " Mapped file inaccessible during execution, " \ 2286 " possible disk/network problem."); 2287 } 2288 } 2289 #endif 2290 st->cr(); 2291 } 2292 2293 2294 static void print_signal_handler(outputStream* st, int sig, 2295 char* buf, size_t buflen); 2296 2297 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) { 2298 st->print_cr("Signal Handlers:"); 2299 print_signal_handler(st, SIGSEGV, buf, buflen); 2300 print_signal_handler(st, SIGBUS , buf, buflen); 2301 print_signal_handler(st, SIGFPE , buf, buflen); 2302 print_signal_handler(st, SIGPIPE, buf, buflen); 2303 print_signal_handler(st, SIGXFSZ, buf, buflen); 2304 print_signal_handler(st, SIGILL , buf, buflen); 2305 print_signal_handler(st, SR_signum, buf, buflen); 2306 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen); 2307 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen); 2308 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen); 2309 print_signal_handler(st, BREAK_SIGNAL, buf, buflen); 2310 #if defined(PPC64) 2311 print_signal_handler(st, SIGTRAP, buf, buflen); 2312 #endif 2313 } 2314 2315 static char saved_jvm_path[MAXPATHLEN] = {0}; 2316 2317 // Find the full path to the current module, libjvm.so 2318 void os::jvm_path(char *buf, jint buflen) { 2319 // Error checking. 2320 if (buflen < MAXPATHLEN) { 2321 assert(false, "must use a large-enough buffer"); 2322 buf[0] = '\0'; 2323 return; 2324 } 2325 // Lazy resolve the path to current module. 2326 if (saved_jvm_path[0] != 0) { 2327 strcpy(buf, saved_jvm_path); 2328 return; 2329 } 2330 2331 char dli_fname[MAXPATHLEN]; 2332 bool ret = dll_address_to_library_name( 2333 CAST_FROM_FN_PTR(address, os::jvm_path), 2334 dli_fname, sizeof(dli_fname), NULL); 2335 assert(ret, "cannot locate libjvm"); 2336 char *rp = NULL; 2337 if (ret && dli_fname[0] != '\0') { 2338 rp = realpath(dli_fname, buf); 2339 } 2340 if (rp == NULL) { 2341 return; 2342 } 2343 2344 if (Arguments::sun_java_launcher_is_altjvm()) { 2345 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical 2346 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". 2347 // If "/jre/lib/" appears at the right place in the string, then 2348 // assume we are installed in a JDK and we're done. Otherwise, check 2349 // for a JAVA_HOME environment variable and fix up the path so it 2350 // looks like libjvm.so is installed there (append a fake suffix 2351 // hotspot/libjvm.so). 2352 const char *p = buf + strlen(buf) - 1; 2353 for (int count = 0; p > buf && count < 5; ++count) { 2354 for (--p; p > buf && *p != '/'; --p) 2355 /* empty */ ; 2356 } 2357 2358 if (strncmp(p, "/jre/lib/", 9) != 0) { 2359 // Look for JAVA_HOME in the environment. 2360 char* java_home_var = ::getenv("JAVA_HOME"); 2361 if (java_home_var != NULL && java_home_var[0] != 0) { 2362 char* jrelib_p; 2363 int len; 2364 2365 // Check the current module name "libjvm.so". 2366 p = strrchr(buf, '/'); 2367 if (p == NULL) { 2368 return; 2369 } 2370 assert(strstr(p, "/libjvm") == p, "invalid library name"); 2371 2372 rp = realpath(java_home_var, buf); 2373 if (rp == NULL) { 2374 return; 2375 } 2376 2377 // determine if this is a legacy image or modules image 2378 // modules image doesn't have "jre" subdirectory 2379 len = strlen(buf); 2380 assert(len < buflen, "Ran out of buffer room"); 2381 jrelib_p = buf + len; 2382 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch); 2383 if (0 != access(buf, F_OK)) { 2384 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch); 2385 } 2386 2387 if (0 == access(buf, F_OK)) { 2388 // Use current module name "libjvm.so" 2389 len = strlen(buf); 2390 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so"); 2391 } else { 2392 // Go back to path of .so 2393 rp = realpath(dli_fname, buf); 2394 if (rp == NULL) { 2395 return; 2396 } 2397 } 2398 } 2399 } 2400 } 2401 2402 strncpy(saved_jvm_path, buf, MAXPATHLEN); 2403 saved_jvm_path[MAXPATHLEN - 1] = '\0'; 2404 } 2405 2406 void os::print_jni_name_prefix_on(outputStream* st, int args_size) { 2407 // no prefix required, not even "_" 2408 } 2409 2410 void os::print_jni_name_suffix_on(outputStream* st, int args_size) { 2411 // no suffix required 2412 } 2413 2414 //////////////////////////////////////////////////////////////////////////////// 2415 // sun.misc.Signal support 2416 2417 static volatile jint sigint_count = 0; 2418 2419 static void UserHandler(int sig, void *siginfo, void *context) { 2420 // 4511530 - sem_post is serialized and handled by the manager thread. When 2421 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We 2422 // don't want to flood the manager thread with sem_post requests. 2423 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) { 2424 return; 2425 } 2426 2427 // Ctrl-C is pressed during error reporting, likely because the error 2428 // handler fails to abort. Let VM die immediately. 2429 if (sig == SIGINT && is_error_reported()) { 2430 os::die(); 2431 } 2432 2433 os::signal_notify(sig); 2434 } 2435 2436 void* os::user_handler() { 2437 return CAST_FROM_FN_PTR(void*, UserHandler); 2438 } 2439 2440 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) { 2441 struct timespec ts; 2442 // Semaphore's are always associated with CLOCK_REALTIME 2443 os::Linux::clock_gettime(CLOCK_REALTIME, &ts); 2444 // see unpackTime for discussion on overflow checking 2445 if (sec >= MAX_SECS) { 2446 ts.tv_sec += MAX_SECS; 2447 ts.tv_nsec = 0; 2448 } else { 2449 ts.tv_sec += sec; 2450 ts.tv_nsec += nsec; 2451 if (ts.tv_nsec >= NANOSECS_PER_SEC) { 2452 ts.tv_nsec -= NANOSECS_PER_SEC; 2453 ++ts.tv_sec; // note: this must be <= max_secs 2454 } 2455 } 2456 2457 return ts; 2458 } 2459 2460 extern "C" { 2461 typedef void (*sa_handler_t)(int); 2462 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *); 2463 } 2464 2465 void* os::signal(int signal_number, void* handler) { 2466 struct sigaction sigAct, oldSigAct; 2467 2468 sigfillset(&(sigAct.sa_mask)); 2469 sigAct.sa_flags = SA_RESTART|SA_SIGINFO; 2470 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler); 2471 2472 if (sigaction(signal_number, &sigAct, &oldSigAct)) { 2473 // -1 means registration failed 2474 return (void *)-1; 2475 } 2476 2477 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler); 2478 } 2479 2480 void os::signal_raise(int signal_number) { 2481 ::raise(signal_number); 2482 } 2483 2484 // The following code is moved from os.cpp for making this 2485 // code platform specific, which it is by its very nature. 2486 2487 // Will be modified when max signal is changed to be dynamic 2488 int os::sigexitnum_pd() { 2489 return NSIG; 2490 } 2491 2492 // a counter for each possible signal value 2493 static volatile jint pending_signals[NSIG+1] = { 0 }; 2494 2495 // Linux(POSIX) specific hand shaking semaphore. 2496 static sem_t sig_sem; 2497 static PosixSemaphore sr_semaphore; 2498 2499 void os::signal_init_pd() { 2500 // Initialize signal structures 2501 ::memset((void*)pending_signals, 0, sizeof(pending_signals)); 2502 2503 // Initialize signal semaphore 2504 ::sem_init(&sig_sem, 0, 0); 2505 } 2506 2507 void os::signal_notify(int sig) { 2508 Atomic::inc(&pending_signals[sig]); 2509 ::sem_post(&sig_sem); 2510 } 2511 2512 static int check_pending_signals(bool wait) { 2513 Atomic::store(0, &sigint_count); 2514 for (;;) { 2515 for (int i = 0; i < NSIG + 1; i++) { 2516 jint n = pending_signals[i]; 2517 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) { 2518 return i; 2519 } 2520 } 2521 if (!wait) { 2522 return -1; 2523 } 2524 JavaThread *thread = JavaThread::current(); 2525 ThreadBlockInVM tbivm(thread); 2526 2527 bool threadIsSuspended; 2528 do { 2529 thread->set_suspend_equivalent(); 2530 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 2531 ::sem_wait(&sig_sem); 2532 2533 // were we externally suspended while we were waiting? 2534 threadIsSuspended = thread->handle_special_suspend_equivalent_condition(); 2535 if (threadIsSuspended) { 2536 // The semaphore has been incremented, but while we were waiting 2537 // another thread suspended us. We don't want to continue running 2538 // while suspended because that would surprise the thread that 2539 // suspended us. 2540 ::sem_post(&sig_sem); 2541 2542 thread->java_suspend_self(); 2543 } 2544 } while (threadIsSuspended); 2545 } 2546 } 2547 2548 int os::signal_lookup() { 2549 return check_pending_signals(false); 2550 } 2551 2552 int os::signal_wait() { 2553 return check_pending_signals(true); 2554 } 2555 2556 //////////////////////////////////////////////////////////////////////////////// 2557 // Virtual Memory 2558 2559 int os::vm_page_size() { 2560 // Seems redundant as all get out 2561 assert(os::Linux::page_size() != -1, "must call os::init"); 2562 return os::Linux::page_size(); 2563 } 2564 2565 // Solaris allocates memory by pages. 2566 int os::vm_allocation_granularity() { 2567 assert(os::Linux::page_size() != -1, "must call os::init"); 2568 return os::Linux::page_size(); 2569 } 2570 2571 // Rationale behind this function: 2572 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable 2573 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get 2574 // samples for JITted code. Here we create private executable mapping over the code cache 2575 // and then we can use standard (well, almost, as mapping can change) way to provide 2576 // info for the reporting script by storing timestamp and location of symbol 2577 void linux_wrap_code(char* base, size_t size) { 2578 static volatile jint cnt = 0; 2579 2580 if (!UseOprofile) { 2581 return; 2582 } 2583 2584 char buf[PATH_MAX+1]; 2585 int num = Atomic::add(1, &cnt); 2586 2587 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d", 2588 os::get_temp_directory(), os::current_process_id(), num); 2589 unlink(buf); 2590 2591 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU); 2592 2593 if (fd != -1) { 2594 off_t rv = ::lseek(fd, size-2, SEEK_SET); 2595 if (rv != (off_t)-1) { 2596 if (::write(fd, "", 1) == 1) { 2597 mmap(base, size, 2598 PROT_READ|PROT_WRITE|PROT_EXEC, 2599 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0); 2600 } 2601 } 2602 ::close(fd); 2603 unlink(buf); 2604 } 2605 } 2606 2607 static bool recoverable_mmap_error(int err) { 2608 // See if the error is one we can let the caller handle. This 2609 // list of errno values comes from JBS-6843484. I can't find a 2610 // Linux man page that documents this specific set of errno 2611 // values so while this list currently matches Solaris, it may 2612 // change as we gain experience with this failure mode. 2613 switch (err) { 2614 case EBADF: 2615 case EINVAL: 2616 case ENOTSUP: 2617 // let the caller deal with these errors 2618 return true; 2619 2620 default: 2621 // Any remaining errors on this OS can cause our reserved mapping 2622 // to be lost. That can cause confusion where different data 2623 // structures think they have the same memory mapped. The worst 2624 // scenario is if both the VM and a library think they have the 2625 // same memory mapped. 2626 return false; 2627 } 2628 } 2629 2630 static void warn_fail_commit_memory(char* addr, size_t size, bool exec, 2631 int err) { 2632 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2633 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec, 2634 strerror(err), err); 2635 } 2636 2637 static void warn_fail_commit_memory(char* addr, size_t size, 2638 size_t alignment_hint, bool exec, 2639 int err) { 2640 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT 2641 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, 2642 alignment_hint, exec, strerror(err), err); 2643 } 2644 2645 // NOTE: Linux kernel does not really reserve the pages for us. 2646 // All it does is to check if there are enough free pages 2647 // left at the time of mmap(). This could be a potential 2648 // problem. 2649 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) { 2650 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 2651 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot, 2652 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0); 2653 if (res != (uintptr_t) MAP_FAILED) { 2654 if (UseNUMAInterleaving) { 2655 numa_make_global(addr, size); 2656 } 2657 return 0; 2658 } 2659 2660 int err = errno; // save errno from mmap() call above 2661 2662 if (!recoverable_mmap_error(err)) { 2663 warn_fail_commit_memory(addr, size, exec, err); 2664 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory."); 2665 } 2666 2667 return err; 2668 } 2669 2670 bool os::pd_commit_memory(char* addr, size_t size, bool exec) { 2671 return os::Linux::commit_memory_impl(addr, size, exec) == 0; 2672 } 2673 2674 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec, 2675 const char* mesg) { 2676 assert(mesg != NULL, "mesg must be specified"); 2677 int err = os::Linux::commit_memory_impl(addr, size, exec); 2678 if (err != 0) { 2679 // the caller wants all commit errors to exit with the specified mesg: 2680 warn_fail_commit_memory(addr, size, exec, err); 2681 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2682 } 2683 } 2684 2685 // Define MAP_HUGETLB here so we can build HotSpot on old systems. 2686 #ifndef MAP_HUGETLB 2687 #define MAP_HUGETLB 0x40000 2688 #endif 2689 2690 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems. 2691 #ifndef MADV_HUGEPAGE 2692 #define MADV_HUGEPAGE 14 2693 #endif 2694 2695 int os::Linux::commit_memory_impl(char* addr, size_t size, 2696 size_t alignment_hint, bool exec) { 2697 int err = os::Linux::commit_memory_impl(addr, size, exec); 2698 if (err == 0) { 2699 realign_memory(addr, size, alignment_hint); 2700 } 2701 return err; 2702 } 2703 2704 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint, 2705 bool exec) { 2706 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0; 2707 } 2708 2709 void os::pd_commit_memory_or_exit(char* addr, size_t size, 2710 size_t alignment_hint, bool exec, 2711 const char* mesg) { 2712 assert(mesg != NULL, "mesg must be specified"); 2713 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec); 2714 if (err != 0) { 2715 // the caller wants all commit errors to exit with the specified mesg: 2716 warn_fail_commit_memory(addr, size, alignment_hint, exec, err); 2717 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg); 2718 } 2719 } 2720 2721 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) { 2722 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) { 2723 // We don't check the return value: madvise(MADV_HUGEPAGE) may not 2724 // be supported or the memory may already be backed by huge pages. 2725 ::madvise(addr, bytes, MADV_HUGEPAGE); 2726 } 2727 } 2728 2729 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) { 2730 // This method works by doing an mmap over an existing mmaping and effectively discarding 2731 // the existing pages. However it won't work for SHM-based large pages that cannot be 2732 // uncommitted at all. We don't do anything in this case to avoid creating a segment with 2733 // small pages on top of the SHM segment. This method always works for small pages, so we 2734 // allow that in any case. 2735 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) { 2736 commit_memory(addr, bytes, alignment_hint, !ExecMem); 2737 } 2738 } 2739 2740 void os::numa_make_global(char *addr, size_t bytes) { 2741 Linux::numa_interleave_memory(addr, bytes); 2742 } 2743 2744 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the 2745 // bind policy to MPOL_PREFERRED for the current thread. 2746 #define USE_MPOL_PREFERRED 0 2747 2748 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) { 2749 // To make NUMA and large pages more robust when both enabled, we need to ease 2750 // the requirements on where the memory should be allocated. MPOL_BIND is the 2751 // default policy and it will force memory to be allocated on the specified 2752 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on 2753 // the specified node, but will not force it. Using this policy will prevent 2754 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no 2755 // free large pages. 2756 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED); 2757 Linux::numa_tonode_memory(addr, bytes, lgrp_hint); 2758 } 2759 2760 bool os::numa_topology_changed() { return false; } 2761 2762 size_t os::numa_get_groups_num() { 2763 int max_node = Linux::numa_max_node(); 2764 return max_node > 0 ? max_node + 1 : 1; 2765 } 2766 2767 int os::numa_get_group_id() { 2768 int cpu_id = Linux::sched_getcpu(); 2769 if (cpu_id != -1) { 2770 int lgrp_id = Linux::get_node_by_cpu(cpu_id); 2771 if (lgrp_id != -1) { 2772 return lgrp_id; 2773 } 2774 } 2775 return 0; 2776 } 2777 2778 size_t os::numa_get_leaf_groups(int *ids, size_t size) { 2779 for (size_t i = 0; i < size; i++) { 2780 ids[i] = i; 2781 } 2782 return size; 2783 } 2784 2785 bool os::get_page_info(char *start, page_info* info) { 2786 return false; 2787 } 2788 2789 char *os::scan_pages(char *start, char* end, page_info* page_expected, 2790 page_info* page_found) { 2791 return end; 2792 } 2793 2794 2795 int os::Linux::sched_getcpu_syscall(void) { 2796 unsigned int cpu = 0; 2797 int retval = -1; 2798 2799 #if defined(IA32) 2800 #ifndef SYS_getcpu 2801 #define SYS_getcpu 318 2802 #endif 2803 retval = syscall(SYS_getcpu, &cpu, NULL, NULL); 2804 #elif defined(AMD64) 2805 // Unfortunately we have to bring all these macros here from vsyscall.h 2806 // to be able to compile on old linuxes. 2807 #define __NR_vgetcpu 2 2808 #define VSYSCALL_START (-10UL << 20) 2809 #define VSYSCALL_SIZE 1024 2810 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr)) 2811 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache); 2812 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu); 2813 retval = vgetcpu(&cpu, NULL, NULL); 2814 #endif 2815 2816 return (retval == -1) ? retval : cpu; 2817 } 2818 2819 // Something to do with the numa-aware allocator needs these symbols 2820 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { } 2821 extern "C" JNIEXPORT void numa_error(char *where) { } 2822 2823 2824 // If we are running with libnuma version > 2, then we should 2825 // be trying to use symbols with versions 1.1 2826 // If we are running with earlier version, which did not have symbol versions, 2827 // we should use the base version. 2828 void* os::Linux::libnuma_dlsym(void* handle, const char *name) { 2829 void *f = dlvsym(handle, name, "libnuma_1.1"); 2830 if (f == NULL) { 2831 f = dlsym(handle, name); 2832 } 2833 return f; 2834 } 2835 2836 bool os::Linux::libnuma_init() { 2837 // sched_getcpu() should be in libc. 2838 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2839 dlsym(RTLD_DEFAULT, "sched_getcpu"))); 2840 2841 // If it's not, try a direct syscall. 2842 if (sched_getcpu() == -1) { 2843 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, 2844 (void*)&sched_getcpu_syscall)); 2845 } 2846 2847 if (sched_getcpu() != -1) { // Does it work? 2848 void *handle = dlopen("libnuma.so.1", RTLD_LAZY); 2849 if (handle != NULL) { 2850 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t, 2851 libnuma_dlsym(handle, "numa_node_to_cpus"))); 2852 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t, 2853 libnuma_dlsym(handle, "numa_max_node"))); 2854 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t, 2855 libnuma_dlsym(handle, "numa_available"))); 2856 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t, 2857 libnuma_dlsym(handle, "numa_tonode_memory"))); 2858 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t, 2859 libnuma_dlsym(handle, "numa_interleave_memory"))); 2860 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t, 2861 libnuma_dlsym(handle, "numa_set_bind_policy"))); 2862 2863 2864 if (numa_available() != -1) { 2865 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes")); 2866 // Create a cpu -> node mapping 2867 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true); 2868 rebuild_cpu_to_node_map(); 2869 return true; 2870 } 2871 } 2872 } 2873 return false; 2874 } 2875 2876 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id. 2877 // The table is later used in get_node_by_cpu(). 2878 void os::Linux::rebuild_cpu_to_node_map() { 2879 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure 2880 // in libnuma (possible values are starting from 16, 2881 // and continuing up with every other power of 2, but less 2882 // than the maximum number of CPUs supported by kernel), and 2883 // is a subject to change (in libnuma version 2 the requirements 2884 // are more reasonable) we'll just hardcode the number they use 2885 // in the library. 2886 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT; 2887 2888 size_t cpu_num = os::active_processor_count(); 2889 size_t cpu_map_size = NCPUS / BitsPerCLong; 2890 size_t cpu_map_valid_size = 2891 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size); 2892 2893 cpu_to_node()->clear(); 2894 cpu_to_node()->at_grow(cpu_num - 1); 2895 size_t node_num = numa_get_groups_num(); 2896 2897 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal); 2898 for (size_t i = 0; i < node_num; i++) { 2899 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) { 2900 for (size_t j = 0; j < cpu_map_valid_size; j++) { 2901 if (cpu_map[j] != 0) { 2902 for (size_t k = 0; k < BitsPerCLong; k++) { 2903 if (cpu_map[j] & (1UL << k)) { 2904 cpu_to_node()->at_put(j * BitsPerCLong + k, i); 2905 } 2906 } 2907 } 2908 } 2909 } 2910 } 2911 FREE_C_HEAP_ARRAY(unsigned long, cpu_map); 2912 } 2913 2914 int os::Linux::get_node_by_cpu(int cpu_id) { 2915 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) { 2916 return cpu_to_node()->at(cpu_id); 2917 } 2918 return -1; 2919 } 2920 2921 GrowableArray<int>* os::Linux::_cpu_to_node; 2922 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu; 2923 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus; 2924 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node; 2925 os::Linux::numa_available_func_t os::Linux::_numa_available; 2926 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory; 2927 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory; 2928 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy; 2929 unsigned long* os::Linux::_numa_all_nodes; 2930 2931 bool os::pd_uncommit_memory(char* addr, size_t size) { 2932 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE, 2933 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0); 2934 return res != (uintptr_t) MAP_FAILED; 2935 } 2936 2937 static address get_stack_commited_bottom(address bottom, size_t size) { 2938 address nbot = bottom; 2939 address ntop = bottom + size; 2940 2941 size_t page_sz = os::vm_page_size(); 2942 unsigned pages = size / page_sz; 2943 2944 unsigned char vec[1]; 2945 unsigned imin = 1, imax = pages + 1, imid; 2946 int mincore_return_value = 0; 2947 2948 assert(imin <= imax, "Unexpected page size"); 2949 2950 while (imin < imax) { 2951 imid = (imax + imin) / 2; 2952 nbot = ntop - (imid * page_sz); 2953 2954 // Use a trick with mincore to check whether the page is mapped or not. 2955 // mincore sets vec to 1 if page resides in memory and to 0 if page 2956 // is swapped output but if page we are asking for is unmapped 2957 // it returns -1,ENOMEM 2958 mincore_return_value = mincore(nbot, page_sz, vec); 2959 2960 if (mincore_return_value == -1) { 2961 // Page is not mapped go up 2962 // to find first mapped page 2963 if (errno != EAGAIN) { 2964 assert(errno == ENOMEM, "Unexpected mincore errno"); 2965 imax = imid; 2966 } 2967 } else { 2968 // Page is mapped go down 2969 // to find first not mapped page 2970 imin = imid + 1; 2971 } 2972 } 2973 2974 nbot = nbot + page_sz; 2975 2976 // Adjust stack bottom one page up if last checked page is not mapped 2977 if (mincore_return_value == -1) { 2978 nbot = nbot + page_sz; 2979 } 2980 2981 return nbot; 2982 } 2983 2984 2985 // Linux uses a growable mapping for the stack, and if the mapping for 2986 // the stack guard pages is not removed when we detach a thread the 2987 // stack cannot grow beyond the pages where the stack guard was 2988 // mapped. If at some point later in the process the stack expands to 2989 // that point, the Linux kernel cannot expand the stack any further 2990 // because the guard pages are in the way, and a segfault occurs. 2991 // 2992 // However, it's essential not to split the stack region by unmapping 2993 // a region (leaving a hole) that's already part of the stack mapping, 2994 // so if the stack mapping has already grown beyond the guard pages at 2995 // the time we create them, we have to truncate the stack mapping. 2996 // So, we need to know the extent of the stack mapping when 2997 // create_stack_guard_pages() is called. 2998 2999 // We only need this for stacks that are growable: at the time of 3000 // writing thread stacks don't use growable mappings (i.e. those 3001 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this 3002 // only applies to the main thread. 3003 3004 // If the (growable) stack mapping already extends beyond the point 3005 // where we're going to put our guard pages, truncate the mapping at 3006 // that point by munmap()ping it. This ensures that when we later 3007 // munmap() the guard pages we don't leave a hole in the stack 3008 // mapping. This only affects the main/initial thread 3009 3010 bool os::pd_create_stack_guard_pages(char* addr, size_t size) { 3011 if (os::Linux::is_initial_thread()) { 3012 // As we manually grow stack up to bottom inside create_attached_thread(), 3013 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and 3014 // we don't need to do anything special. 3015 // Check it first, before calling heavy function. 3016 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom(); 3017 unsigned char vec[1]; 3018 3019 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) { 3020 // Fallback to slow path on all errors, including EAGAIN 3021 stack_extent = (uintptr_t) get_stack_commited_bottom( 3022 os::Linux::initial_thread_stack_bottom(), 3023 (size_t)addr - stack_extent); 3024 } 3025 3026 if (stack_extent < (uintptr_t)addr) { 3027 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent)); 3028 } 3029 } 3030 3031 return os::commit_memory(addr, size, !ExecMem); 3032 } 3033 3034 // If this is a growable mapping, remove the guard pages entirely by 3035 // munmap()ping them. If not, just call uncommit_memory(). This only 3036 // affects the main/initial thread, but guard against future OS changes 3037 // It's safe to always unmap guard pages for initial thread because we 3038 // always place it right after end of the mapped region 3039 3040 bool os::remove_stack_guard_pages(char* addr, size_t size) { 3041 uintptr_t stack_extent, stack_base; 3042 3043 if (os::Linux::is_initial_thread()) { 3044 return ::munmap(addr, size) == 0; 3045 } 3046 3047 return os::uncommit_memory(addr, size); 3048 } 3049 3050 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory 3051 // at 'requested_addr'. If there are existing memory mappings at the same 3052 // location, however, they will be overwritten. If 'fixed' is false, 3053 // 'requested_addr' is only treated as a hint, the return value may or 3054 // may not start from the requested address. Unlike Linux mmap(), this 3055 // function returns NULL to indicate failure. 3056 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) { 3057 char * addr; 3058 int flags; 3059 3060 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; 3061 if (fixed) { 3062 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address"); 3063 flags |= MAP_FIXED; 3064 } 3065 3066 // Map reserved/uncommitted pages PROT_NONE so we fail early if we 3067 // touch an uncommitted page. Otherwise, the read/write might 3068 // succeed if we have enough swap space to back the physical page. 3069 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, 3070 flags, -1, 0); 3071 3072 return addr == MAP_FAILED ? NULL : addr; 3073 } 3074 3075 static int anon_munmap(char * addr, size_t size) { 3076 return ::munmap(addr, size) == 0; 3077 } 3078 3079 char* os::pd_reserve_memory(size_t bytes, char* requested_addr, 3080 size_t alignment_hint) { 3081 return anon_mmap(requested_addr, bytes, (requested_addr != NULL)); 3082 } 3083 3084 bool os::pd_release_memory(char* addr, size_t size) { 3085 return anon_munmap(addr, size); 3086 } 3087 3088 static bool linux_mprotect(char* addr, size_t size, int prot) { 3089 // Linux wants the mprotect address argument to be page aligned. 3090 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size()); 3091 3092 // According to SUSv3, mprotect() should only be used with mappings 3093 // established by mmap(), and mmap() always maps whole pages. Unaligned 3094 // 'addr' likely indicates problem in the VM (e.g. trying to change 3095 // protection of malloc'ed or statically allocated memory). Check the 3096 // caller if you hit this assert. 3097 assert(addr == bottom, "sanity check"); 3098 3099 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size()); 3100 return ::mprotect(bottom, size, prot) == 0; 3101 } 3102 3103 // Set protections specified 3104 bool os::protect_memory(char* addr, size_t bytes, ProtType prot, 3105 bool is_committed) { 3106 unsigned int p = 0; 3107 switch (prot) { 3108 case MEM_PROT_NONE: p = PROT_NONE; break; 3109 case MEM_PROT_READ: p = PROT_READ; break; 3110 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break; 3111 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break; 3112 default: 3113 ShouldNotReachHere(); 3114 } 3115 // is_committed is unused. 3116 return linux_mprotect(addr, bytes, p); 3117 } 3118 3119 bool os::guard_memory(char* addr, size_t size) { 3120 return linux_mprotect(addr, size, PROT_NONE); 3121 } 3122 3123 bool os::unguard_memory(char* addr, size_t size) { 3124 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE); 3125 } 3126 3127 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, 3128 size_t page_size) { 3129 bool result = false; 3130 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE, 3131 MAP_ANONYMOUS|MAP_PRIVATE, 3132 -1, 0); 3133 if (p != MAP_FAILED) { 3134 void *aligned_p = align_ptr_up(p, page_size); 3135 3136 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0; 3137 3138 munmap(p, page_size * 2); 3139 } 3140 3141 if (warn && !result) { 3142 warning("TransparentHugePages is not supported by the operating system."); 3143 } 3144 3145 return result; 3146 } 3147 3148 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) { 3149 bool result = false; 3150 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE, 3151 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB, 3152 -1, 0); 3153 3154 if (p != MAP_FAILED) { 3155 // We don't know if this really is a huge page or not. 3156 FILE *fp = fopen("/proc/self/maps", "r"); 3157 if (fp) { 3158 while (!feof(fp)) { 3159 char chars[257]; 3160 long x = 0; 3161 if (fgets(chars, sizeof(chars), fp)) { 3162 if (sscanf(chars, "%lx-%*x", &x) == 1 3163 && x == (long)p) { 3164 if (strstr (chars, "hugepage")) { 3165 result = true; 3166 break; 3167 } 3168 } 3169 } 3170 } 3171 fclose(fp); 3172 } 3173 munmap(p, page_size); 3174 } 3175 3176 if (warn && !result) { 3177 warning("HugeTLBFS is not supported by the operating system."); 3178 } 3179 3180 return result; 3181 } 3182 3183 // Set the coredump_filter bits to include largepages in core dump (bit 6) 3184 // 3185 // From the coredump_filter documentation: 3186 // 3187 // - (bit 0) anonymous private memory 3188 // - (bit 1) anonymous shared memory 3189 // - (bit 2) file-backed private memory 3190 // - (bit 3) file-backed shared memory 3191 // - (bit 4) ELF header pages in file-backed private memory areas (it is 3192 // effective only if the bit 2 is cleared) 3193 // - (bit 5) hugetlb private memory 3194 // - (bit 6) hugetlb shared memory 3195 // 3196 static void set_coredump_filter(void) { 3197 FILE *f; 3198 long cdm; 3199 3200 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) { 3201 return; 3202 } 3203 3204 if (fscanf(f, "%lx", &cdm) != 1) { 3205 fclose(f); 3206 return; 3207 } 3208 3209 rewind(f); 3210 3211 if ((cdm & LARGEPAGES_BIT) == 0) { 3212 cdm |= LARGEPAGES_BIT; 3213 fprintf(f, "%#lx", cdm); 3214 } 3215 3216 fclose(f); 3217 } 3218 3219 // Large page support 3220 3221 static size_t _large_page_size = 0; 3222 3223 size_t os::Linux::find_large_page_size() { 3224 size_t large_page_size = 0; 3225 3226 // large_page_size on Linux is used to round up heap size. x86 uses either 3227 // 2M or 4M page, depending on whether PAE (Physical Address Extensions) 3228 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use 3229 // page as large as 256M. 3230 // 3231 // Here we try to figure out page size by parsing /proc/meminfo and looking 3232 // for a line with the following format: 3233 // Hugepagesize: 2048 kB 3234 // 3235 // If we can't determine the value (e.g. /proc is not mounted, or the text 3236 // format has been changed), we'll use the largest page size supported by 3237 // the processor. 3238 3239 #ifndef ZERO 3240 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M) 3241 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M); 3242 #endif // ZERO 3243 3244 FILE *fp = fopen("/proc/meminfo", "r"); 3245 if (fp) { 3246 while (!feof(fp)) { 3247 int x = 0; 3248 char buf[16]; 3249 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) { 3250 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) { 3251 large_page_size = x * K; 3252 break; 3253 } 3254 } else { 3255 // skip to next line 3256 for (;;) { 3257 int ch = fgetc(fp); 3258 if (ch == EOF || ch == (int)'\n') break; 3259 } 3260 } 3261 } 3262 fclose(fp); 3263 } 3264 3265 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) { 3266 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is " 3267 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size), 3268 proper_unit_for_byte_size(large_page_size)); 3269 } 3270 3271 return large_page_size; 3272 } 3273 3274 size_t os::Linux::setup_large_page_size() { 3275 _large_page_size = Linux::find_large_page_size(); 3276 const size_t default_page_size = (size_t)Linux::page_size(); 3277 if (_large_page_size > default_page_size) { 3278 _page_sizes[0] = _large_page_size; 3279 _page_sizes[1] = default_page_size; 3280 _page_sizes[2] = 0; 3281 } 3282 3283 return _large_page_size; 3284 } 3285 3286 bool os::Linux::setup_large_page_type(size_t page_size) { 3287 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && 3288 FLAG_IS_DEFAULT(UseSHM) && 3289 FLAG_IS_DEFAULT(UseTransparentHugePages)) { 3290 3291 // The type of large pages has not been specified by the user. 3292 3293 // Try UseHugeTLBFS and then UseSHM. 3294 UseHugeTLBFS = UseSHM = true; 3295 3296 // Don't try UseTransparentHugePages since there are known 3297 // performance issues with it turned on. This might change in the future. 3298 UseTransparentHugePages = false; 3299 } 3300 3301 if (UseTransparentHugePages) { 3302 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages); 3303 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) { 3304 UseHugeTLBFS = false; 3305 UseSHM = false; 3306 return true; 3307 } 3308 UseTransparentHugePages = false; 3309 } 3310 3311 if (UseHugeTLBFS) { 3312 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS); 3313 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) { 3314 UseSHM = false; 3315 return true; 3316 } 3317 UseHugeTLBFS = false; 3318 } 3319 3320 return UseSHM; 3321 } 3322 3323 void os::large_page_init() { 3324 if (!UseLargePages && 3325 !UseTransparentHugePages && 3326 !UseHugeTLBFS && 3327 !UseSHM) { 3328 // Not using large pages. 3329 return; 3330 } 3331 3332 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) { 3333 // The user explicitly turned off large pages. 3334 // Ignore the rest of the large pages flags. 3335 UseTransparentHugePages = false; 3336 UseHugeTLBFS = false; 3337 UseSHM = false; 3338 return; 3339 } 3340 3341 size_t large_page_size = Linux::setup_large_page_size(); 3342 UseLargePages = Linux::setup_large_page_type(large_page_size); 3343 3344 set_coredump_filter(); 3345 } 3346 3347 #ifndef SHM_HUGETLB 3348 #define SHM_HUGETLB 04000 3349 #endif 3350 3351 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, 3352 char* req_addr, bool exec) { 3353 // "exec" is passed in but not used. Creating the shared image for 3354 // the code cache doesn't have an SHM_X executable permission to check. 3355 assert(UseLargePages && UseSHM, "only for SHM large pages"); 3356 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3357 3358 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) { 3359 return NULL; // Fallback to small pages. 3360 } 3361 3362 key_t key = IPC_PRIVATE; 3363 char *addr; 3364 3365 bool warn_on_failure = UseLargePages && 3366 (!FLAG_IS_DEFAULT(UseLargePages) || 3367 !FLAG_IS_DEFAULT(UseSHM) || 3368 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3369 char msg[128]; 3370 3371 // Create a large shared memory region to attach to based on size. 3372 // Currently, size is the total size of the heap 3373 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W); 3374 if (shmid == -1) { 3375 // Possible reasons for shmget failure: 3376 // 1. shmmax is too small for Java heap. 3377 // > check shmmax value: cat /proc/sys/kernel/shmmax 3378 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax 3379 // 2. not enough large page memory. 3380 // > check available large pages: cat /proc/meminfo 3381 // > increase amount of large pages: 3382 // echo new_value > /proc/sys/vm/nr_hugepages 3383 // Note 1: different Linux may use different name for this property, 3384 // e.g. on Redhat AS-3 it is "hugetlb_pool". 3385 // Note 2: it's possible there's enough physical memory available but 3386 // they are so fragmented after a long run that they can't 3387 // coalesce into large pages. Try to reserve large pages when 3388 // the system is still "fresh". 3389 if (warn_on_failure) { 3390 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno); 3391 warning("%s", msg); 3392 } 3393 return NULL; 3394 } 3395 3396 // attach to the region 3397 addr = (char*)shmat(shmid, req_addr, 0); 3398 int err = errno; 3399 3400 // Remove shmid. If shmat() is successful, the actual shared memory segment 3401 // will be deleted when it's detached by shmdt() or when the process 3402 // terminates. If shmat() is not successful this will remove the shared 3403 // segment immediately. 3404 shmctl(shmid, IPC_RMID, NULL); 3405 3406 if ((intptr_t)addr == -1) { 3407 if (warn_on_failure) { 3408 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err); 3409 warning("%s", msg); 3410 } 3411 return NULL; 3412 } 3413 3414 return addr; 3415 } 3416 3417 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, 3418 int error) { 3419 assert(error == ENOMEM, "Only expect to fail if no memory is available"); 3420 3421 bool warn_on_failure = UseLargePages && 3422 (!FLAG_IS_DEFAULT(UseLargePages) || 3423 !FLAG_IS_DEFAULT(UseHugeTLBFS) || 3424 !FLAG_IS_DEFAULT(LargePageSizeInBytes)); 3425 3426 if (warn_on_failure) { 3427 char msg[128]; 3428 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: " 3429 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error); 3430 warning("%s", msg); 3431 } 3432 } 3433 3434 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, 3435 char* req_addr, 3436 bool exec) { 3437 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3438 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size"); 3439 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address"); 3440 3441 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3442 char* addr = (char*)::mmap(req_addr, bytes, prot, 3443 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 3444 -1, 0); 3445 3446 if (addr == MAP_FAILED) { 3447 warn_on_large_pages_failure(req_addr, bytes, errno); 3448 return NULL; 3449 } 3450 3451 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be"); 3452 3453 return addr; 3454 } 3455 3456 // Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed(). 3457 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address 3458 // (req_addr != NULL) or with a given alignment. 3459 // - bytes shall be a multiple of alignment. 3460 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3461 // - alignment sets the alignment at which memory shall be allocated. 3462 // It must be a multiple of allocation granularity. 3463 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3464 // req_addr or NULL. 3465 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) { 3466 3467 size_t extra_size = bytes; 3468 if (req_addr == NULL && alignment > 0) { 3469 extra_size += alignment; 3470 } 3471 3472 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE, 3473 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 3474 -1, 0); 3475 if (start == MAP_FAILED) { 3476 start = NULL; 3477 } else { 3478 if (req_addr != NULL) { 3479 if (start != req_addr) { 3480 ::munmap(start, extra_size); 3481 start = NULL; 3482 } 3483 } else { 3484 char* const start_aligned = (char*) align_ptr_up(start, alignment); 3485 char* const end_aligned = start_aligned + bytes; 3486 char* const end = start + extra_size; 3487 if (start_aligned > start) { 3488 ::munmap(start, start_aligned - start); 3489 } 3490 if (end_aligned < end) { 3491 ::munmap(end_aligned, end - end_aligned); 3492 } 3493 start = start_aligned; 3494 } 3495 } 3496 return start; 3497 3498 } 3499 3500 // Reserve memory using mmap(MAP_HUGETLB). 3501 // - bytes shall be a multiple of alignment. 3502 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment. 3503 // - alignment sets the alignment at which memory shall be allocated. 3504 // It must be a multiple of allocation granularity. 3505 // Returns address of memory or NULL. If req_addr was not NULL, will only return 3506 // req_addr or NULL. 3507 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, 3508 size_t alignment, 3509 char* req_addr, 3510 bool exec) { 3511 size_t large_page_size = os::large_page_size(); 3512 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes"); 3513 3514 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3515 assert(is_size_aligned(bytes, alignment), "Must be"); 3516 3517 // First reserve - but not commit - the address range in small pages. 3518 char* const start = anon_mmap_aligned(bytes, alignment, req_addr); 3519 3520 if (start == NULL) { 3521 return NULL; 3522 } 3523 3524 assert(is_ptr_aligned(start, alignment), "Must be"); 3525 3526 char* end = start + bytes; 3527 3528 // Find the regions of the allocated chunk that can be promoted to large pages. 3529 char* lp_start = (char*)align_ptr_up(start, large_page_size); 3530 char* lp_end = (char*)align_ptr_down(end, large_page_size); 3531 3532 size_t lp_bytes = lp_end - lp_start; 3533 3534 assert(is_size_aligned(lp_bytes, large_page_size), "Must be"); 3535 3536 if (lp_bytes == 0) { 3537 // The mapped region doesn't even span the start and the end of a large page. 3538 // Fall back to allocate a non-special area. 3539 ::munmap(start, end - start); 3540 return NULL; 3541 } 3542 3543 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE; 3544 3545 void* result; 3546 3547 // Commit small-paged leading area. 3548 if (start != lp_start) { 3549 result = ::mmap(start, lp_start - start, prot, 3550 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3551 -1, 0); 3552 if (result == MAP_FAILED) { 3553 ::munmap(lp_start, end - lp_start); 3554 return NULL; 3555 } 3556 } 3557 3558 // Commit large-paged area. 3559 result = ::mmap(lp_start, lp_bytes, prot, 3560 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB, 3561 -1, 0); 3562 if (result == MAP_FAILED) { 3563 warn_on_large_pages_failure(lp_start, lp_bytes, errno); 3564 // If the mmap above fails, the large pages region will be unmapped and we 3565 // have regions before and after with small pages. Release these regions. 3566 // 3567 // | mapped | unmapped | mapped | 3568 // ^ ^ ^ ^ 3569 // start lp_start lp_end end 3570 // 3571 ::munmap(start, lp_start - start); 3572 ::munmap(lp_end, end - lp_end); 3573 return NULL; 3574 } 3575 3576 // Commit small-paged trailing area. 3577 if (lp_end != end) { 3578 result = ::mmap(lp_end, end - lp_end, prot, 3579 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 3580 -1, 0); 3581 if (result == MAP_FAILED) { 3582 ::munmap(start, lp_end - start); 3583 return NULL; 3584 } 3585 } 3586 3587 return start; 3588 } 3589 3590 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, 3591 size_t alignment, 3592 char* req_addr, 3593 bool exec) { 3594 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages"); 3595 assert(is_ptr_aligned(req_addr, alignment), "Must be"); 3596 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be"); 3597 assert(is_power_of_2(os::large_page_size()), "Must be"); 3598 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes"); 3599 3600 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) { 3601 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec); 3602 } else { 3603 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec); 3604 } 3605 } 3606 3607 char* os::reserve_memory_special(size_t bytes, size_t alignment, 3608 char* req_addr, bool exec) { 3609 assert(UseLargePages, "only for large pages"); 3610 3611 char* addr; 3612 if (UseSHM) { 3613 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec); 3614 } else { 3615 assert(UseHugeTLBFS, "must be"); 3616 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec); 3617 } 3618 3619 if (addr != NULL) { 3620 if (UseNUMAInterleaving) { 3621 numa_make_global(addr, bytes); 3622 } 3623 3624 // The memory is committed 3625 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC); 3626 } 3627 3628 return addr; 3629 } 3630 3631 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) { 3632 // detaching the SHM segment will also delete it, see reserve_memory_special_shm() 3633 return shmdt(base) == 0; 3634 } 3635 3636 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) { 3637 return pd_release_memory(base, bytes); 3638 } 3639 3640 bool os::release_memory_special(char* base, size_t bytes) { 3641 bool res; 3642 if (MemTracker::tracking_level() > NMT_minimal) { 3643 Tracker tkr = MemTracker::get_virtual_memory_release_tracker(); 3644 res = os::Linux::release_memory_special_impl(base, bytes); 3645 if (res) { 3646 tkr.record((address)base, bytes); 3647 } 3648 3649 } else { 3650 res = os::Linux::release_memory_special_impl(base, bytes); 3651 } 3652 return res; 3653 } 3654 3655 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) { 3656 assert(UseLargePages, "only for large pages"); 3657 bool res; 3658 3659 if (UseSHM) { 3660 res = os::Linux::release_memory_special_shm(base, bytes); 3661 } else { 3662 assert(UseHugeTLBFS, "must be"); 3663 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes); 3664 } 3665 return res; 3666 } 3667 3668 size_t os::large_page_size() { 3669 return _large_page_size; 3670 } 3671 3672 // With SysV SHM the entire memory region must be allocated as shared 3673 // memory. 3674 // HugeTLBFS allows application to commit large page memory on demand. 3675 // However, when committing memory with HugeTLBFS fails, the region 3676 // that was supposed to be committed will lose the old reservation 3677 // and allow other threads to steal that memory region. Because of this 3678 // behavior we can't commit HugeTLBFS memory. 3679 bool os::can_commit_large_page_memory() { 3680 return UseTransparentHugePages; 3681 } 3682 3683 bool os::can_execute_large_page_memory() { 3684 return UseTransparentHugePages || UseHugeTLBFS; 3685 } 3686 3687 // Reserve memory at an arbitrary address, only if that area is 3688 // available (and not reserved for something else). 3689 3690 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) { 3691 const int max_tries = 10; 3692 char* base[max_tries]; 3693 size_t size[max_tries]; 3694 const size_t gap = 0x000000; 3695 3696 // Assert only that the size is a multiple of the page size, since 3697 // that's all that mmap requires, and since that's all we really know 3698 // about at this low abstraction level. If we need higher alignment, 3699 // we can either pass an alignment to this method or verify alignment 3700 // in one of the methods further up the call chain. See bug 5044738. 3701 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block"); 3702 3703 // Repeatedly allocate blocks until the block is allocated at the 3704 // right spot. 3705 3706 // Linux mmap allows caller to pass an address as hint; give it a try first, 3707 // if kernel honors the hint then we can return immediately. 3708 char * addr = anon_mmap(requested_addr, bytes, false); 3709 if (addr == requested_addr) { 3710 return requested_addr; 3711 } 3712 3713 if (addr != NULL) { 3714 // mmap() is successful but it fails to reserve at the requested address 3715 anon_munmap(addr, bytes); 3716 } 3717 3718 int i; 3719 for (i = 0; i < max_tries; ++i) { 3720 base[i] = reserve_memory(bytes); 3721 3722 if (base[i] != NULL) { 3723 // Is this the block we wanted? 3724 if (base[i] == requested_addr) { 3725 size[i] = bytes; 3726 break; 3727 } 3728 3729 // Does this overlap the block we wanted? Give back the overlapped 3730 // parts and try again. 3731 3732 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i]; 3733 if (top_overlap >= 0 && (size_t)top_overlap < bytes) { 3734 unmap_memory(base[i], top_overlap); 3735 base[i] += top_overlap; 3736 size[i] = bytes - top_overlap; 3737 } else { 3738 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr; 3739 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) { 3740 unmap_memory(requested_addr, bottom_overlap); 3741 size[i] = bytes - bottom_overlap; 3742 } else { 3743 size[i] = bytes; 3744 } 3745 } 3746 } 3747 } 3748 3749 // Give back the unused reserved pieces. 3750 3751 for (int j = 0; j < i; ++j) { 3752 if (base[j] != NULL) { 3753 unmap_memory(base[j], size[j]); 3754 } 3755 } 3756 3757 if (i < max_tries) { 3758 return requested_addr; 3759 } else { 3760 return NULL; 3761 } 3762 } 3763 3764 size_t os::read(int fd, void *buf, unsigned int nBytes) { 3765 return ::read(fd, buf, nBytes); 3766 } 3767 3768 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) { 3769 return ::pread(fd, buf, nBytes, offset); 3770 } 3771 3772 // Short sleep, direct OS call. 3773 // 3774 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee 3775 // sched_yield(2) will actually give up the CPU: 3776 // 3777 // * Alone on this pariticular CPU, keeps running. 3778 // * Before the introduction of "skip_buddy" with "compat_yield" disabled 3779 // (pre 2.6.39). 3780 // 3781 // So calling this with 0 is an alternative. 3782 // 3783 void os::naked_short_sleep(jlong ms) { 3784 struct timespec req; 3785 3786 assert(ms < 1000, "Un-interruptable sleep, short time use only"); 3787 req.tv_sec = 0; 3788 if (ms > 0) { 3789 req.tv_nsec = (ms % 1000) * 1000000; 3790 } else { 3791 req.tv_nsec = 1; 3792 } 3793 3794 nanosleep(&req, NULL); 3795 3796 return; 3797 } 3798 3799 // Sleep forever; naked call to OS-specific sleep; use with CAUTION 3800 void os::infinite_sleep() { 3801 while (true) { // sleep forever ... 3802 ::sleep(100); // ... 100 seconds at a time 3803 } 3804 } 3805 3806 // Used to convert frequent JVM_Yield() to nops 3807 bool os::dont_yield() { 3808 return DontYieldALot; 3809 } 3810 3811 void os::naked_yield() { 3812 sched_yield(); 3813 } 3814 3815 //////////////////////////////////////////////////////////////////////////////// 3816 // thread priority support 3817 3818 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER 3819 // only supports dynamic priority, static priority must be zero. For real-time 3820 // applications, Linux supports SCHED_RR which allows static priority (1-99). 3821 // However, for large multi-threaded applications, SCHED_RR is not only slower 3822 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out 3823 // of 5 runs - Sep 2005). 3824 // 3825 // The following code actually changes the niceness of kernel-thread/LWP. It 3826 // has an assumption that setpriority() only modifies one kernel-thread/LWP, 3827 // not the entire user process, and user level threads are 1:1 mapped to kernel 3828 // threads. It has always been the case, but could change in the future. For 3829 // this reason, the code should not be used as default (ThreadPriorityPolicy=0). 3830 // It is only used when ThreadPriorityPolicy=1 and requires root privilege. 3831 3832 int os::java_to_os_priority[CriticalPriority + 1] = { 3833 19, // 0 Entry should never be used 3834 3835 4, // 1 MinPriority 3836 3, // 2 3837 2, // 3 3838 3839 1, // 4 3840 0, // 5 NormPriority 3841 -1, // 6 3842 3843 -2, // 7 3844 -3, // 8 3845 -4, // 9 NearMaxPriority 3846 3847 -5, // 10 MaxPriority 3848 3849 -5 // 11 CriticalPriority 3850 }; 3851 3852 static int prio_init() { 3853 if (ThreadPriorityPolicy == 1) { 3854 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1 3855 // if effective uid is not root. Perhaps, a more elegant way of doing 3856 // this is to test CAP_SYS_NICE capability, but that will require libcap.so 3857 if (geteuid() != 0) { 3858 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) { 3859 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux"); 3860 } 3861 ThreadPriorityPolicy = 0; 3862 } 3863 } 3864 if (UseCriticalJavaThreadPriority) { 3865 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority]; 3866 } 3867 return 0; 3868 } 3869 3870 OSReturn os::set_native_priority(Thread* thread, int newpri) { 3871 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK; 3872 3873 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri); 3874 return (ret == 0) ? OS_OK : OS_ERR; 3875 } 3876 3877 OSReturn os::get_native_priority(const Thread* const thread, 3878 int *priority_ptr) { 3879 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) { 3880 *priority_ptr = java_to_os_priority[NormPriority]; 3881 return OS_OK; 3882 } 3883 3884 errno = 0; 3885 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id()); 3886 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR); 3887 } 3888 3889 // Hint to the underlying OS that a task switch would not be good. 3890 // Void return because it's a hint and can fail. 3891 void os::hint_no_preempt() {} 3892 3893 //////////////////////////////////////////////////////////////////////////////// 3894 // suspend/resume support 3895 3896 // the low-level signal-based suspend/resume support is a remnant from the 3897 // old VM-suspension that used to be for java-suspension, safepoints etc, 3898 // within hotspot. Now there is a single use-case for this: 3899 // - calling get_thread_pc() on the VMThread by the flat-profiler task 3900 // that runs in the watcher thread. 3901 // The remaining code is greatly simplified from the more general suspension 3902 // code that used to be used. 3903 // 3904 // The protocol is quite simple: 3905 // - suspend: 3906 // - sends a signal to the target thread 3907 // - polls the suspend state of the osthread using a yield loop 3908 // - target thread signal handler (SR_handler) sets suspend state 3909 // and blocks in sigsuspend until continued 3910 // - resume: 3911 // - sets target osthread state to continue 3912 // - sends signal to end the sigsuspend loop in the SR_handler 3913 // 3914 // Note that the SR_lock plays no role in this suspend/resume protocol. 3915 3916 static void resume_clear_context(OSThread *osthread) { 3917 osthread->set_ucontext(NULL); 3918 osthread->set_siginfo(NULL); 3919 } 3920 3921 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, 3922 ucontext_t* context) { 3923 osthread->set_ucontext(context); 3924 osthread->set_siginfo(siginfo); 3925 } 3926 3927 // Handler function invoked when a thread's execution is suspended or 3928 // resumed. We have to be careful that only async-safe functions are 3929 // called here (Note: most pthread functions are not async safe and 3930 // should be avoided.) 3931 // 3932 // Note: sigwait() is a more natural fit than sigsuspend() from an 3933 // interface point of view, but sigwait() prevents the signal hander 3934 // from being run. libpthread would get very confused by not having 3935 // its signal handlers run and prevents sigwait()'s use with the 3936 // mutex granting granting signal. 3937 // 3938 // Currently only ever called on the VMThread and JavaThreads (PC sampling) 3939 // 3940 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) { 3941 // Save and restore errno to avoid confusing native code with EINTR 3942 // after sigsuspend. 3943 int old_errno = errno; 3944 3945 Thread* thread = Thread::current(); 3946 OSThread* osthread = thread->osthread(); 3947 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread"); 3948 3949 os::SuspendResume::State current = osthread->sr.state(); 3950 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) { 3951 suspend_save_context(osthread, siginfo, context); 3952 3953 // attempt to switch the state, we assume we had a SUSPEND_REQUEST 3954 os::SuspendResume::State state = osthread->sr.suspended(); 3955 if (state == os::SuspendResume::SR_SUSPENDED) { 3956 sigset_t suspend_set; // signals for sigsuspend() 3957 3958 // get current set of blocked signals and unblock resume signal 3959 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set); 3960 sigdelset(&suspend_set, SR_signum); 3961 3962 sr_semaphore.signal(); 3963 // wait here until we are resumed 3964 while (1) { 3965 sigsuspend(&suspend_set); 3966 3967 os::SuspendResume::State result = osthread->sr.running(); 3968 if (result == os::SuspendResume::SR_RUNNING) { 3969 sr_semaphore.signal(); 3970 break; 3971 } 3972 } 3973 3974 } else if (state == os::SuspendResume::SR_RUNNING) { 3975 // request was cancelled, continue 3976 } else { 3977 ShouldNotReachHere(); 3978 } 3979 3980 resume_clear_context(osthread); 3981 } else if (current == os::SuspendResume::SR_RUNNING) { 3982 // request was cancelled, continue 3983 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) { 3984 // ignore 3985 } else { 3986 // ignore 3987 } 3988 3989 errno = old_errno; 3990 } 3991 3992 static int SR_initialize() { 3993 struct sigaction act; 3994 char *s; 3995 3996 // Get signal number to use for suspend/resume 3997 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) { 3998 int sig = ::strtol(s, 0, 10); 3999 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769. 4000 sig < NSIG) { // Must be legal signal and fit into sigflags[]. 4001 SR_signum = sig; 4002 } else { 4003 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.", 4004 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum); 4005 } 4006 } 4007 4008 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS, 4009 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769"); 4010 4011 sigemptyset(&SR_sigset); 4012 sigaddset(&SR_sigset, SR_signum); 4013 4014 // Set up signal handler for suspend/resume 4015 act.sa_flags = SA_RESTART|SA_SIGINFO; 4016 act.sa_handler = (void (*)(int)) SR_handler; 4017 4018 // SR_signum is blocked by default. 4019 // 4528190 - We also need to block pthread restart signal (32 on all 4020 // supported Linux platforms). Note that LinuxThreads need to block 4021 // this signal for all threads to work properly. So we don't have 4022 // to use hard-coded signal number when setting up the mask. 4023 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask); 4024 4025 if (sigaction(SR_signum, &act, 0) == -1) { 4026 return -1; 4027 } 4028 4029 // Save signal flag 4030 os::Linux::set_our_sigflags(SR_signum, act.sa_flags); 4031 return 0; 4032 } 4033 4034 static int sr_notify(OSThread* osthread) { 4035 int status = pthread_kill(osthread->pthread_id(), SR_signum); 4036 assert_status(status == 0, status, "pthread_kill"); 4037 return status; 4038 } 4039 4040 // "Randomly" selected value for how long we want to spin 4041 // before bailing out on suspending a thread, also how often 4042 // we send a signal to a thread we want to resume 4043 static const int RANDOMLY_LARGE_INTEGER = 1000000; 4044 static const int RANDOMLY_LARGE_INTEGER2 = 100; 4045 4046 // returns true on success and false on error - really an error is fatal 4047 // but this seems the normal response to library errors 4048 static bool do_suspend(OSThread* osthread) { 4049 assert(osthread->sr.is_running(), "thread should be running"); 4050 assert(!sr_semaphore.trywait(), "semaphore has invalid state"); 4051 4052 // mark as suspended and send signal 4053 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) { 4054 // failed to switch, state wasn't running? 4055 ShouldNotReachHere(); 4056 return false; 4057 } 4058 4059 if (sr_notify(osthread) != 0) { 4060 ShouldNotReachHere(); 4061 } 4062 4063 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED 4064 while (true) { 4065 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4066 break; 4067 } else { 4068 // timeout 4069 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend(); 4070 if (cancelled == os::SuspendResume::SR_RUNNING) { 4071 return false; 4072 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) { 4073 // make sure that we consume the signal on the semaphore as well 4074 sr_semaphore.wait(); 4075 break; 4076 } else { 4077 ShouldNotReachHere(); 4078 return false; 4079 } 4080 } 4081 } 4082 4083 guarantee(osthread->sr.is_suspended(), "Must be suspended"); 4084 return true; 4085 } 4086 4087 static void do_resume(OSThread* osthread) { 4088 assert(osthread->sr.is_suspended(), "thread should be suspended"); 4089 assert(!sr_semaphore.trywait(), "invalid semaphore state"); 4090 4091 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) { 4092 // failed to switch to WAKEUP_REQUEST 4093 ShouldNotReachHere(); 4094 return; 4095 } 4096 4097 while (true) { 4098 if (sr_notify(osthread) == 0) { 4099 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) { 4100 if (osthread->sr.is_running()) { 4101 return; 4102 } 4103 } 4104 } else { 4105 ShouldNotReachHere(); 4106 } 4107 } 4108 4109 guarantee(osthread->sr.is_running(), "Must be running!"); 4110 } 4111 4112 /////////////////////////////////////////////////////////////////////////////////// 4113 // signal handling (except suspend/resume) 4114 4115 // This routine may be used by user applications as a "hook" to catch signals. 4116 // The user-defined signal handler must pass unrecognized signals to this 4117 // routine, and if it returns true (non-zero), then the signal handler must 4118 // return immediately. If the flag "abort_if_unrecognized" is true, then this 4119 // routine will never retun false (zero), but instead will execute a VM panic 4120 // routine kill the process. 4121 // 4122 // If this routine returns false, it is OK to call it again. This allows 4123 // the user-defined signal handler to perform checks either before or after 4124 // the VM performs its own checks. Naturally, the user code would be making 4125 // a serious error if it tried to handle an exception (such as a null check 4126 // or breakpoint) that the VM was generating for its own correct operation. 4127 // 4128 // This routine may recognize any of the following kinds of signals: 4129 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1. 4130 // It should be consulted by handlers for any of those signals. 4131 // 4132 // The caller of this routine must pass in the three arguments supplied 4133 // to the function referred to in the "sa_sigaction" (not the "sa_handler") 4134 // field of the structure passed to sigaction(). This routine assumes that 4135 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART. 4136 // 4137 // Note that the VM will print warnings if it detects conflicting signal 4138 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers". 4139 // 4140 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo, 4141 siginfo_t* siginfo, 4142 void* ucontext, 4143 int abort_if_unrecognized); 4144 4145 void signalHandler(int sig, siginfo_t* info, void* uc) { 4146 assert(info != NULL && uc != NULL, "it must be old kernel"); 4147 int orig_errno = errno; // Preserve errno value over signal handler. 4148 JVM_handle_linux_signal(sig, info, uc, true); 4149 errno = orig_errno; 4150 } 4151 4152 4153 // This boolean allows users to forward their own non-matching signals 4154 // to JVM_handle_linux_signal, harmlessly. 4155 bool os::Linux::signal_handlers_are_installed = false; 4156 4157 // For signal-chaining 4158 struct sigaction sigact[NSIG]; 4159 uint64_t sigs = 0; 4160 #if (64 < NSIG-1) 4161 #error "Not all signals can be encoded in sigs. Adapt its type!" 4162 #endif 4163 bool os::Linux::libjsig_is_loaded = false; 4164 typedef struct sigaction *(*get_signal_t)(int); 4165 get_signal_t os::Linux::get_signal_action = NULL; 4166 4167 struct sigaction* os::Linux::get_chained_signal_action(int sig) { 4168 struct sigaction *actp = NULL; 4169 4170 if (libjsig_is_loaded) { 4171 // Retrieve the old signal handler from libjsig 4172 actp = (*get_signal_action)(sig); 4173 } 4174 if (actp == NULL) { 4175 // Retrieve the preinstalled signal handler from jvm 4176 actp = get_preinstalled_handler(sig); 4177 } 4178 4179 return actp; 4180 } 4181 4182 static bool call_chained_handler(struct sigaction *actp, int sig, 4183 siginfo_t *siginfo, void *context) { 4184 // Call the old signal handler 4185 if (actp->sa_handler == SIG_DFL) { 4186 // It's more reasonable to let jvm treat it as an unexpected exception 4187 // instead of taking the default action. 4188 return false; 4189 } else if (actp->sa_handler != SIG_IGN) { 4190 if ((actp->sa_flags & SA_NODEFER) == 0) { 4191 // automaticlly block the signal 4192 sigaddset(&(actp->sa_mask), sig); 4193 } 4194 4195 sa_handler_t hand = NULL; 4196 sa_sigaction_t sa = NULL; 4197 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0; 4198 // retrieve the chained handler 4199 if (siginfo_flag_set) { 4200 sa = actp->sa_sigaction; 4201 } else { 4202 hand = actp->sa_handler; 4203 } 4204 4205 if ((actp->sa_flags & SA_RESETHAND) != 0) { 4206 actp->sa_handler = SIG_DFL; 4207 } 4208 4209 // try to honor the signal mask 4210 sigset_t oset; 4211 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset); 4212 4213 // call into the chained handler 4214 if (siginfo_flag_set) { 4215 (*sa)(sig, siginfo, context); 4216 } else { 4217 (*hand)(sig); 4218 } 4219 4220 // restore the signal mask 4221 pthread_sigmask(SIG_SETMASK, &oset, 0); 4222 } 4223 // Tell jvm's signal handler the signal is taken care of. 4224 return true; 4225 } 4226 4227 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) { 4228 bool chained = false; 4229 // signal-chaining 4230 if (UseSignalChaining) { 4231 struct sigaction *actp = get_chained_signal_action(sig); 4232 if (actp != NULL) { 4233 chained = call_chained_handler(actp, sig, siginfo, context); 4234 } 4235 } 4236 return chained; 4237 } 4238 4239 struct sigaction* os::Linux::get_preinstalled_handler(int sig) { 4240 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) { 4241 return &sigact[sig]; 4242 } 4243 return NULL; 4244 } 4245 4246 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) { 4247 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4248 sigact[sig] = oldAct; 4249 sigs |= (uint64_t)1 << (sig-1); 4250 } 4251 4252 // for diagnostic 4253 int sigflags[NSIG]; 4254 4255 int os::Linux::get_our_sigflags(int sig) { 4256 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4257 return sigflags[sig]; 4258 } 4259 4260 void os::Linux::set_our_sigflags(int sig, int flags) { 4261 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4262 if (sig > 0 && sig < NSIG) { 4263 sigflags[sig] = flags; 4264 } 4265 } 4266 4267 void os::Linux::set_signal_handler(int sig, bool set_installed) { 4268 // Check for overwrite. 4269 struct sigaction oldAct; 4270 sigaction(sig, (struct sigaction*)NULL, &oldAct); 4271 4272 void* oldhand = oldAct.sa_sigaction 4273 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4274 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4275 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) && 4276 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) && 4277 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) { 4278 if (AllowUserSignalHandlers || !set_installed) { 4279 // Do not overwrite; user takes responsibility to forward to us. 4280 return; 4281 } else if (UseSignalChaining) { 4282 // save the old handler in jvm 4283 save_preinstalled_handler(sig, oldAct); 4284 // libjsig also interposes the sigaction() call below and saves the 4285 // old sigaction on it own. 4286 } else { 4287 fatal("Encountered unexpected pre-existing sigaction handler " 4288 "%#lx for signal %d.", (long)oldhand, sig); 4289 } 4290 } 4291 4292 struct sigaction sigAct; 4293 sigfillset(&(sigAct.sa_mask)); 4294 sigAct.sa_handler = SIG_DFL; 4295 if (!set_installed) { 4296 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4297 } else { 4298 sigAct.sa_sigaction = signalHandler; 4299 sigAct.sa_flags = SA_SIGINFO|SA_RESTART; 4300 } 4301 // Save flags, which are set by ours 4302 assert(sig > 0 && sig < NSIG, "vm signal out of expected range"); 4303 sigflags[sig] = sigAct.sa_flags; 4304 4305 int ret = sigaction(sig, &sigAct, &oldAct); 4306 assert(ret == 0, "check"); 4307 4308 void* oldhand2 = oldAct.sa_sigaction 4309 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction) 4310 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler); 4311 assert(oldhand2 == oldhand, "no concurrent signal handler installation"); 4312 } 4313 4314 // install signal handlers for signals that HotSpot needs to 4315 // handle in order to support Java-level exception handling. 4316 4317 void os::Linux::install_signal_handlers() { 4318 if (!signal_handlers_are_installed) { 4319 signal_handlers_are_installed = true; 4320 4321 // signal-chaining 4322 typedef void (*signal_setting_t)(); 4323 signal_setting_t begin_signal_setting = NULL; 4324 signal_setting_t end_signal_setting = NULL; 4325 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4326 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting")); 4327 if (begin_signal_setting != NULL) { 4328 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t, 4329 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting")); 4330 get_signal_action = CAST_TO_FN_PTR(get_signal_t, 4331 dlsym(RTLD_DEFAULT, "JVM_get_signal_action")); 4332 libjsig_is_loaded = true; 4333 assert(UseSignalChaining, "should enable signal-chaining"); 4334 } 4335 if (libjsig_is_loaded) { 4336 // Tell libjsig jvm is setting signal handlers 4337 (*begin_signal_setting)(); 4338 } 4339 4340 set_signal_handler(SIGSEGV, true); 4341 set_signal_handler(SIGPIPE, true); 4342 set_signal_handler(SIGBUS, true); 4343 set_signal_handler(SIGILL, true); 4344 set_signal_handler(SIGFPE, true); 4345 #if defined(PPC64) 4346 set_signal_handler(SIGTRAP, true); 4347 #endif 4348 set_signal_handler(SIGXFSZ, true); 4349 4350 if (libjsig_is_loaded) { 4351 // Tell libjsig jvm finishes setting signal handlers 4352 (*end_signal_setting)(); 4353 } 4354 4355 // We don't activate signal checker if libjsig is in place, we trust ourselves 4356 // and if UserSignalHandler is installed all bets are off. 4357 // Log that signal checking is off only if -verbose:jni is specified. 4358 if (CheckJNICalls) { 4359 if (libjsig_is_loaded) { 4360 if (PrintJNIResolving) { 4361 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled"); 4362 } 4363 check_signals = false; 4364 } 4365 if (AllowUserSignalHandlers) { 4366 if (PrintJNIResolving) { 4367 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled"); 4368 } 4369 check_signals = false; 4370 } 4371 } 4372 } 4373 } 4374 4375 // This is the fastest way to get thread cpu time on Linux. 4376 // Returns cpu time (user+sys) for any thread, not only for current. 4377 // POSIX compliant clocks are implemented in the kernels 2.6.16+. 4378 // It might work on 2.6.10+ with a special kernel/glibc patch. 4379 // For reference, please, see IEEE Std 1003.1-2004: 4380 // http://www.unix.org/single_unix_specification 4381 4382 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) { 4383 struct timespec tp; 4384 int rc = os::Linux::clock_gettime(clockid, &tp); 4385 assert(rc == 0, "clock_gettime is expected to return 0 code"); 4386 4387 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec; 4388 } 4389 4390 ///// 4391 // glibc on Linux platform uses non-documented flag 4392 // to indicate, that some special sort of signal 4393 // trampoline is used. 4394 // We will never set this flag, and we should 4395 // ignore this flag in our diagnostic 4396 #ifdef SIGNIFICANT_SIGNAL_MASK 4397 #undef SIGNIFICANT_SIGNAL_MASK 4398 #endif 4399 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000) 4400 4401 static const char* get_signal_handler_name(address handler, 4402 char* buf, int buflen) { 4403 int offset = 0; 4404 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset); 4405 if (found) { 4406 // skip directory names 4407 const char *p1, *p2; 4408 p1 = buf; 4409 size_t len = strlen(os::file_separator()); 4410 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len; 4411 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset); 4412 } else { 4413 jio_snprintf(buf, buflen, PTR_FORMAT, handler); 4414 } 4415 return buf; 4416 } 4417 4418 static void print_signal_handler(outputStream* st, int sig, 4419 char* buf, size_t buflen) { 4420 struct sigaction sa; 4421 4422 sigaction(sig, NULL, &sa); 4423 4424 // See comment for SIGNIFICANT_SIGNAL_MASK define 4425 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4426 4427 st->print("%s: ", os::exception_name(sig, buf, buflen)); 4428 4429 address handler = (sa.sa_flags & SA_SIGINFO) 4430 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction) 4431 : CAST_FROM_FN_PTR(address, sa.sa_handler); 4432 4433 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) { 4434 st->print("SIG_DFL"); 4435 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) { 4436 st->print("SIG_IGN"); 4437 } else { 4438 st->print("[%s]", get_signal_handler_name(handler, buf, buflen)); 4439 } 4440 4441 st->print(", sa_mask[0]="); 4442 os::Posix::print_signal_set_short(st, &sa.sa_mask); 4443 4444 address rh = VMError::get_resetted_sighandler(sig); 4445 // May be, handler was resetted by VMError? 4446 if (rh != NULL) { 4447 handler = rh; 4448 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK; 4449 } 4450 4451 st->print(", sa_flags="); 4452 os::Posix::print_sa_flags(st, sa.sa_flags); 4453 4454 // Check: is it our handler? 4455 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) || 4456 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) { 4457 // It is our signal handler 4458 // check for flags, reset system-used one! 4459 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) { 4460 st->print( 4461 ", flags was changed from " PTR32_FORMAT ", consider using jsig library", 4462 os::Linux::get_our_sigflags(sig)); 4463 } 4464 } 4465 st->cr(); 4466 } 4467 4468 4469 #define DO_SIGNAL_CHECK(sig) \ 4470 do { \ 4471 if (!sigismember(&check_signal_done, sig)) { \ 4472 os::Linux::check_signal_handler(sig); \ 4473 } \ 4474 } while (0) 4475 4476 // This method is a periodic task to check for misbehaving JNI applications 4477 // under CheckJNI, we can add any periodic checks here 4478 4479 void os::run_periodic_checks() { 4480 if (check_signals == false) return; 4481 4482 // SEGV and BUS if overridden could potentially prevent 4483 // generation of hs*.log in the event of a crash, debugging 4484 // such a case can be very challenging, so we absolutely 4485 // check the following for a good measure: 4486 DO_SIGNAL_CHECK(SIGSEGV); 4487 DO_SIGNAL_CHECK(SIGILL); 4488 DO_SIGNAL_CHECK(SIGFPE); 4489 DO_SIGNAL_CHECK(SIGBUS); 4490 DO_SIGNAL_CHECK(SIGPIPE); 4491 DO_SIGNAL_CHECK(SIGXFSZ); 4492 #if defined(PPC64) 4493 DO_SIGNAL_CHECK(SIGTRAP); 4494 #endif 4495 4496 // ReduceSignalUsage allows the user to override these handlers 4497 // see comments at the very top and jvm_solaris.h 4498 if (!ReduceSignalUsage) { 4499 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL); 4500 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL); 4501 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL); 4502 DO_SIGNAL_CHECK(BREAK_SIGNAL); 4503 } 4504 4505 DO_SIGNAL_CHECK(SR_signum); 4506 } 4507 4508 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *); 4509 4510 static os_sigaction_t os_sigaction = NULL; 4511 4512 void os::Linux::check_signal_handler(int sig) { 4513 char buf[O_BUFLEN]; 4514 address jvmHandler = NULL; 4515 4516 4517 struct sigaction act; 4518 if (os_sigaction == NULL) { 4519 // only trust the default sigaction, in case it has been interposed 4520 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction"); 4521 if (os_sigaction == NULL) return; 4522 } 4523 4524 os_sigaction(sig, (struct sigaction*)NULL, &act); 4525 4526 4527 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK; 4528 4529 address thisHandler = (act.sa_flags & SA_SIGINFO) 4530 ? CAST_FROM_FN_PTR(address, act.sa_sigaction) 4531 : CAST_FROM_FN_PTR(address, act.sa_handler); 4532 4533 4534 switch (sig) { 4535 case SIGSEGV: 4536 case SIGBUS: 4537 case SIGFPE: 4538 case SIGPIPE: 4539 case SIGILL: 4540 case SIGXFSZ: 4541 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler); 4542 break; 4543 4544 case SHUTDOWN1_SIGNAL: 4545 case SHUTDOWN2_SIGNAL: 4546 case SHUTDOWN3_SIGNAL: 4547 case BREAK_SIGNAL: 4548 jvmHandler = (address)user_handler(); 4549 break; 4550 4551 default: 4552 if (sig == SR_signum) { 4553 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler); 4554 } else { 4555 return; 4556 } 4557 break; 4558 } 4559 4560 if (thisHandler != jvmHandler) { 4561 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN)); 4562 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN)); 4563 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN)); 4564 // No need to check this sig any longer 4565 sigaddset(&check_signal_done, sig); 4566 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN 4567 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) { 4568 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell", 4569 exception_name(sig, buf, O_BUFLEN)); 4570 } 4571 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) { 4572 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN)); 4573 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig)); 4574 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags); 4575 // No need to check this sig any longer 4576 sigaddset(&check_signal_done, sig); 4577 } 4578 4579 // Dump all the signal 4580 if (sigismember(&check_signal_done, sig)) { 4581 print_signal_handlers(tty, buf, O_BUFLEN); 4582 } 4583 } 4584 4585 extern void report_error(char* file_name, int line_no, char* title, 4586 char* format, ...); 4587 4588 extern bool signal_name(int signo, char* buf, size_t len); 4589 4590 const char* os::exception_name(int exception_code, char* buf, size_t size) { 4591 if (0 < exception_code && exception_code <= SIGRTMAX) { 4592 // signal 4593 if (!signal_name(exception_code, buf, size)) { 4594 jio_snprintf(buf, size, "SIG%d", exception_code); 4595 } 4596 return buf; 4597 } else { 4598 return NULL; 4599 } 4600 } 4601 4602 // this is called _before_ the most of global arguments have been parsed 4603 void os::init(void) { 4604 char dummy; // used to get a guess on initial stack address 4605 // first_hrtime = gethrtime(); 4606 4607 clock_tics_per_sec = sysconf(_SC_CLK_TCK); 4608 4609 init_random(1234567); 4610 4611 ThreadCritical::initialize(); 4612 4613 Linux::set_page_size(sysconf(_SC_PAGESIZE)); 4614 if (Linux::page_size() == -1) { 4615 fatal("os_linux.cpp: os::init: sysconf failed (%s)", 4616 strerror(errno)); 4617 } 4618 init_page_sizes((size_t) Linux::page_size()); 4619 4620 Linux::initialize_system_info(); 4621 4622 // main_thread points to the aboriginal thread 4623 Linux::_main_thread = pthread_self(); 4624 4625 Linux::clock_init(); 4626 initial_time_count = javaTimeNanos(); 4627 4628 // pthread_condattr initialization for monotonic clock 4629 int status; 4630 pthread_condattr_t* _condattr = os::Linux::condAttr(); 4631 if ((status = pthread_condattr_init(_condattr)) != 0) { 4632 fatal("pthread_condattr_init: %s", strerror(status)); 4633 } 4634 // Only set the clock if CLOCK_MONOTONIC is available 4635 if (os::supports_monotonic_clock()) { 4636 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) { 4637 if (status == EINVAL) { 4638 warning("Unable to use monotonic clock with relative timed-waits" \ 4639 " - changes to the time-of-day clock may have adverse affects"); 4640 } else { 4641 fatal("pthread_condattr_setclock: %s", strerror(status)); 4642 } 4643 } 4644 } 4645 // else it defaults to CLOCK_REALTIME 4646 4647 // If the pagesize of the VM is greater than 8K determine the appropriate 4648 // number of initial guard pages. The user can change this with the 4649 // command line arguments, if needed. 4650 if (vm_page_size() > (int)Linux::vm_default_page_size()) { 4651 StackYellowPages = 1; 4652 StackRedPages = 1; 4653 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size(); 4654 } 4655 4656 // retrieve entry point for pthread_setname_np 4657 Linux::_pthread_setname_np = 4658 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np"); 4659 4660 } 4661 4662 // To install functions for atexit system call 4663 extern "C" { 4664 static void perfMemory_exit_helper() { 4665 perfMemory_exit(); 4666 } 4667 } 4668 4669 // this is called _after_ the global arguments have been parsed 4670 jint os::init_2(void) { 4671 Linux::fast_thread_clock_init(); 4672 4673 // Allocate a single page and mark it as readable for safepoint polling 4674 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4675 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page"); 4676 4677 os::set_polling_page(polling_page); 4678 4679 #ifndef PRODUCT 4680 if (Verbose && PrintMiscellaneous) { 4681 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", 4682 (intptr_t)polling_page); 4683 } 4684 #endif 4685 4686 if (!UseMembar) { 4687 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 4688 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page"); 4689 os::set_memory_serialize_page(mem_serialize_page); 4690 4691 #ifndef PRODUCT 4692 if (Verbose && PrintMiscellaneous) { 4693 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", 4694 (intptr_t)mem_serialize_page); 4695 } 4696 #endif 4697 } 4698 4699 // initialize suspend/resume support - must do this before signal_sets_init() 4700 if (SR_initialize() != 0) { 4701 perror("SR_initialize failed"); 4702 return JNI_ERR; 4703 } 4704 4705 Linux::signal_sets_init(); 4706 Linux::install_signal_handlers(); 4707 4708 // Check minimum allowable stack size for thread creation and to initialize 4709 // the java system classes, including StackOverflowError - depends on page 4710 // size. Add a page for compiler2 recursion in main thread. 4711 // Add in 2*BytesPerWord times page size to account for VM stack during 4712 // class initialization depending on 32 or 64 bit VM. 4713 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed, 4714 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() + 4715 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size()); 4716 4717 size_t threadStackSizeInBytes = ThreadStackSize * K; 4718 if (threadStackSizeInBytes != 0 && 4719 threadStackSizeInBytes < os::Linux::min_stack_allowed) { 4720 tty->print_cr("\nThe stack size specified is too small, " 4721 "Specify at least " SIZE_FORMAT "k", 4722 os::Linux::min_stack_allowed/ K); 4723 return JNI_ERR; 4724 } 4725 4726 // Make the stack size a multiple of the page size so that 4727 // the yellow/red zones can be guarded. 4728 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes, 4729 vm_page_size())); 4730 4731 Linux::capture_initial_stack(JavaThread::stack_size_at_create()); 4732 4733 #if defined(IA32) 4734 workaround_expand_exec_shield_cs_limit(); 4735 #endif 4736 4737 Linux::libpthread_init(); 4738 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4739 tty->print_cr("[HotSpot is running with %s, %s]\n", 4740 Linux::glibc_version(), Linux::libpthread_version()); 4741 } 4742 4743 if (UseNUMA) { 4744 if (!Linux::libnuma_init()) { 4745 UseNUMA = false; 4746 } else { 4747 if ((Linux::numa_max_node() < 1)) { 4748 // There's only one node(they start from 0), disable NUMA. 4749 UseNUMA = false; 4750 } 4751 } 4752 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way 4753 // we can make the adaptive lgrp chunk resizing work. If the user specified 4754 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and 4755 // disable adaptive resizing. 4756 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) { 4757 if (FLAG_IS_DEFAULT(UseNUMA)) { 4758 UseNUMA = false; 4759 } else { 4760 if (FLAG_IS_DEFAULT(UseLargePages) && 4761 FLAG_IS_DEFAULT(UseSHM) && 4762 FLAG_IS_DEFAULT(UseHugeTLBFS)) { 4763 UseLargePages = false; 4764 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) { 4765 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)"); 4766 UseAdaptiveSizePolicy = false; 4767 UseAdaptiveNUMAChunkSizing = false; 4768 } 4769 } 4770 } 4771 if (!UseNUMA && ForceNUMA) { 4772 UseNUMA = true; 4773 } 4774 } 4775 4776 if (MaxFDLimit) { 4777 // set the number of file descriptors to max. print out error 4778 // if getrlimit/setrlimit fails but continue regardless. 4779 struct rlimit nbr_files; 4780 int status = getrlimit(RLIMIT_NOFILE, &nbr_files); 4781 if (status != 0) { 4782 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4783 perror("os::init_2 getrlimit failed"); 4784 } 4785 } else { 4786 nbr_files.rlim_cur = nbr_files.rlim_max; 4787 status = setrlimit(RLIMIT_NOFILE, &nbr_files); 4788 if (status != 0) { 4789 if (PrintMiscellaneous && (Verbose || WizardMode)) { 4790 perror("os::init_2 setrlimit failed"); 4791 } 4792 } 4793 } 4794 } 4795 4796 // Initialize lock used to serialize thread creation (see os::create_thread) 4797 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false)); 4798 4799 // at-exit methods are called in the reverse order of their registration. 4800 // atexit functions are called on return from main or as a result of a 4801 // call to exit(3C). There can be only 32 of these functions registered 4802 // and atexit() does not set errno. 4803 4804 if (PerfAllowAtExitRegistration) { 4805 // only register atexit functions if PerfAllowAtExitRegistration is set. 4806 // atexit functions can be delayed until process exit time, which 4807 // can be problematic for embedded VM situations. Embedded VMs should 4808 // call DestroyJavaVM() to assure that VM resources are released. 4809 4810 // note: perfMemory_exit_helper atexit function may be removed in 4811 // the future if the appropriate cleanup code can be added to the 4812 // VM_Exit VMOperation's doit method. 4813 if (atexit(perfMemory_exit_helper) != 0) { 4814 warning("os::init_2 atexit(perfMemory_exit_helper) failed"); 4815 } 4816 } 4817 4818 // initialize thread priority policy 4819 prio_init(); 4820 4821 return JNI_OK; 4822 } 4823 4824 // Mark the polling page as unreadable 4825 void os::make_polling_page_unreadable(void) { 4826 if (!guard_memory((char*)_polling_page, Linux::page_size())) { 4827 fatal("Could not disable polling page"); 4828 } 4829 } 4830 4831 // Mark the polling page as readable 4832 void os::make_polling_page_readable(void) { 4833 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) { 4834 fatal("Could not enable polling page"); 4835 } 4836 } 4837 4838 int os::active_processor_count() { 4839 // Linux doesn't yet have a (official) notion of processor sets, 4840 // so just return the number of online processors. 4841 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN); 4842 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check"); 4843 return online_cpus; 4844 } 4845 4846 void os::set_native_thread_name(const char *name) { 4847 if (Linux::_pthread_setname_np) { 4848 char buf [16]; // according to glibc manpage, 16 chars incl. '/0' 4849 snprintf(buf, sizeof(buf), "%s", name); 4850 buf[sizeof(buf) - 1] = '\0'; 4851 const int rc = Linux::_pthread_setname_np(pthread_self(), buf); 4852 // ERANGE should not happen; all other errors should just be ignored. 4853 assert(rc != ERANGE, "pthread_setname_np failed"); 4854 } 4855 } 4856 4857 bool os::distribute_processes(uint length, uint* distribution) { 4858 // Not yet implemented. 4859 return false; 4860 } 4861 4862 bool os::bind_to_processor(uint processor_id) { 4863 // Not yet implemented. 4864 return false; 4865 } 4866 4867 /// 4868 4869 void os::SuspendedThreadTask::internal_do_task() { 4870 if (do_suspend(_thread->osthread())) { 4871 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext()); 4872 do_task(context); 4873 do_resume(_thread->osthread()); 4874 } 4875 } 4876 4877 class PcFetcher : public os::SuspendedThreadTask { 4878 public: 4879 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {} 4880 ExtendedPC result(); 4881 protected: 4882 void do_task(const os::SuspendedThreadTaskContext& context); 4883 private: 4884 ExtendedPC _epc; 4885 }; 4886 4887 ExtendedPC PcFetcher::result() { 4888 guarantee(is_done(), "task is not done yet."); 4889 return _epc; 4890 } 4891 4892 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) { 4893 Thread* thread = context.thread(); 4894 OSThread* osthread = thread->osthread(); 4895 if (osthread->ucontext() != NULL) { 4896 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext()); 4897 } else { 4898 // NULL context is unexpected, double-check this is the VMThread 4899 guarantee(thread->is_VM_thread(), "can only be called for VMThread"); 4900 } 4901 } 4902 4903 // Suspends the target using the signal mechanism and then grabs the PC before 4904 // resuming the target. Used by the flat-profiler only 4905 ExtendedPC os::get_thread_pc(Thread* thread) { 4906 // Make sure that it is called by the watcher for the VMThread 4907 assert(Thread::current()->is_Watcher_thread(), "Must be watcher"); 4908 assert(thread->is_VM_thread(), "Can only be called for VMThread"); 4909 4910 PcFetcher fetcher(thread); 4911 fetcher.run(); 4912 return fetcher.result(); 4913 } 4914 4915 //////////////////////////////////////////////////////////////////////////////// 4916 // debug support 4917 4918 bool os::find(address addr, outputStream* st) { 4919 Dl_info dlinfo; 4920 memset(&dlinfo, 0, sizeof(dlinfo)); 4921 if (dladdr(addr, &dlinfo) != 0) { 4922 st->print(PTR_FORMAT ": ", p2i(addr)); 4923 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) { 4924 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname, 4925 p2i(addr) - p2i(dlinfo.dli_saddr)); 4926 } else if (dlinfo.dli_fbase != NULL) { 4927 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase)); 4928 } else { 4929 st->print("<absolute address>"); 4930 } 4931 if (dlinfo.dli_fname != NULL) { 4932 st->print(" in %s", dlinfo.dli_fname); 4933 } 4934 if (dlinfo.dli_fbase != NULL) { 4935 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase)); 4936 } 4937 st->cr(); 4938 4939 if (Verbose) { 4940 // decode some bytes around the PC 4941 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size()); 4942 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size()); 4943 address lowest = (address) dlinfo.dli_sname; 4944 if (!lowest) lowest = (address) dlinfo.dli_fbase; 4945 if (begin < lowest) begin = lowest; 4946 Dl_info dlinfo2; 4947 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr 4948 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) { 4949 end = (address) dlinfo2.dli_saddr; 4950 } 4951 Disassembler::decode(begin, end, st); 4952 } 4953 return true; 4954 } 4955 return false; 4956 } 4957 4958 //////////////////////////////////////////////////////////////////////////////// 4959 // misc 4960 4961 // This does not do anything on Linux. This is basically a hook for being 4962 // able to use structured exception handling (thread-local exception filters) 4963 // on, e.g., Win32. 4964 void 4965 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method, 4966 JavaCallArguments* args, Thread* thread) { 4967 f(value, method, args, thread); 4968 } 4969 4970 void os::print_statistics() { 4971 } 4972 4973 bool os::message_box(const char* title, const char* message) { 4974 int i; 4975 fdStream err(defaultStream::error_fd()); 4976 for (i = 0; i < 78; i++) err.print_raw("="); 4977 err.cr(); 4978 err.print_raw_cr(title); 4979 for (i = 0; i < 78; i++) err.print_raw("-"); 4980 err.cr(); 4981 err.print_raw_cr(message); 4982 for (i = 0; i < 78; i++) err.print_raw("="); 4983 err.cr(); 4984 4985 char buf[16]; 4986 // Prevent process from exiting upon "read error" without consuming all CPU 4987 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); } 4988 4989 return buf[0] == 'y' || buf[0] == 'Y'; 4990 } 4991 4992 int os::stat(const char *path, struct stat *sbuf) { 4993 char pathbuf[MAX_PATH]; 4994 if (strlen(path) > MAX_PATH - 1) { 4995 errno = ENAMETOOLONG; 4996 return -1; 4997 } 4998 os::native_path(strcpy(pathbuf, path)); 4999 return ::stat(pathbuf, sbuf); 5000 } 5001 5002 bool os::check_heap(bool force) { 5003 return true; 5004 } 5005 5006 // Is a (classpath) directory empty? 5007 bool os::dir_is_empty(const char* path) { 5008 DIR *dir = NULL; 5009 struct dirent *ptr; 5010 5011 dir = opendir(path); 5012 if (dir == NULL) return true; 5013 5014 // Scan the directory 5015 bool result = true; 5016 char buf[sizeof(struct dirent) + MAX_PATH]; 5017 while (result && (ptr = ::readdir(dir)) != NULL) { 5018 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) { 5019 result = false; 5020 } 5021 } 5022 closedir(dir); 5023 return result; 5024 } 5025 5026 // This code originates from JDK's sysOpen and open64_w 5027 // from src/solaris/hpi/src/system_md.c 5028 5029 int os::open(const char *path, int oflag, int mode) { 5030 if (strlen(path) > MAX_PATH - 1) { 5031 errno = ENAMETOOLONG; 5032 return -1; 5033 } 5034 5035 // All file descriptors that are opened in the Java process and not 5036 // specifically destined for a subprocess should have the close-on-exec 5037 // flag set. If we don't set it, then careless 3rd party native code 5038 // might fork and exec without closing all appropriate file descriptors 5039 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in 5040 // turn might: 5041 // 5042 // - cause end-of-file to fail to be detected on some file 5043 // descriptors, resulting in mysterious hangs, or 5044 // 5045 // - might cause an fopen in the subprocess to fail on a system 5046 // suffering from bug 1085341. 5047 // 5048 // (Yes, the default setting of the close-on-exec flag is a Unix 5049 // design flaw) 5050 // 5051 // See: 5052 // 1085341: 32-bit stdio routines should support file descriptors >255 5053 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed 5054 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9 5055 // 5056 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open(). 5057 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor 5058 // because it saves a system call and removes a small window where the flag 5059 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored 5060 // and we fall back to using FD_CLOEXEC (see below). 5061 #ifdef O_CLOEXEC 5062 oflag |= O_CLOEXEC; 5063 #endif 5064 5065 int fd = ::open64(path, oflag, mode); 5066 if (fd == -1) return -1; 5067 5068 //If the open succeeded, the file might still be a directory 5069 { 5070 struct stat64 buf64; 5071 int ret = ::fstat64(fd, &buf64); 5072 int st_mode = buf64.st_mode; 5073 5074 if (ret != -1) { 5075 if ((st_mode & S_IFMT) == S_IFDIR) { 5076 errno = EISDIR; 5077 ::close(fd); 5078 return -1; 5079 } 5080 } else { 5081 ::close(fd); 5082 return -1; 5083 } 5084 } 5085 5086 #ifdef FD_CLOEXEC 5087 // Validate that the use of the O_CLOEXEC flag on open above worked. 5088 // With recent kernels, we will perform this check exactly once. 5089 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0; 5090 if (!O_CLOEXEC_is_known_to_work) { 5091 int flags = ::fcntl(fd, F_GETFD); 5092 if (flags != -1) { 5093 if ((flags & FD_CLOEXEC) != 0) 5094 O_CLOEXEC_is_known_to_work = 1; 5095 else 5096 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC); 5097 } 5098 } 5099 #endif 5100 5101 return fd; 5102 } 5103 5104 5105 // create binary file, rewriting existing file if required 5106 int os::create_binary_file(const char* path, bool rewrite_existing) { 5107 int oflags = O_WRONLY | O_CREAT; 5108 if (!rewrite_existing) { 5109 oflags |= O_EXCL; 5110 } 5111 return ::open64(path, oflags, S_IREAD | S_IWRITE); 5112 } 5113 5114 // return current position of file pointer 5115 jlong os::current_file_offset(int fd) { 5116 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR); 5117 } 5118 5119 // move file pointer to the specified offset 5120 jlong os::seek_to_file_offset(int fd, jlong offset) { 5121 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET); 5122 } 5123 5124 // This code originates from JDK's sysAvailable 5125 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c 5126 5127 int os::available(int fd, jlong *bytes) { 5128 jlong cur, end; 5129 int mode; 5130 struct stat64 buf64; 5131 5132 if (::fstat64(fd, &buf64) >= 0) { 5133 mode = buf64.st_mode; 5134 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { 5135 int n; 5136 if (::ioctl(fd, FIONREAD, &n) >= 0) { 5137 *bytes = n; 5138 return 1; 5139 } 5140 } 5141 } 5142 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) { 5143 return 0; 5144 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) { 5145 return 0; 5146 } else if (::lseek64(fd, cur, SEEK_SET) == -1) { 5147 return 0; 5148 } 5149 *bytes = end - cur; 5150 return 1; 5151 } 5152 5153 // Map a block of memory. 5154 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset, 5155 char *addr, size_t bytes, bool read_only, 5156 bool allow_exec) { 5157 int prot; 5158 int flags = MAP_PRIVATE; 5159 5160 if (read_only) { 5161 prot = PROT_READ; 5162 } else { 5163 prot = PROT_READ | PROT_WRITE; 5164 } 5165 5166 if (allow_exec) { 5167 prot |= PROT_EXEC; 5168 } 5169 5170 if (addr != NULL) { 5171 flags |= MAP_FIXED; 5172 } 5173 5174 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags, 5175 fd, file_offset); 5176 if (mapped_address == MAP_FAILED) { 5177 return NULL; 5178 } 5179 return mapped_address; 5180 } 5181 5182 5183 // Remap a block of memory. 5184 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, 5185 char *addr, size_t bytes, bool read_only, 5186 bool allow_exec) { 5187 // same as map_memory() on this OS 5188 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only, 5189 allow_exec); 5190 } 5191 5192 5193 // Unmap a block of memory. 5194 bool os::pd_unmap_memory(char* addr, size_t bytes) { 5195 return munmap(addr, bytes) == 0; 5196 } 5197 5198 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time); 5199 5200 static clockid_t thread_cpu_clockid(Thread* thread) { 5201 pthread_t tid = thread->osthread()->pthread_id(); 5202 clockid_t clockid; 5203 5204 // Get thread clockid 5205 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid); 5206 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code"); 5207 return clockid; 5208 } 5209 5210 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool) 5211 // are used by JVM M&M and JVMTI to get user+sys or user CPU time 5212 // of a thread. 5213 // 5214 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns 5215 // the fast estimate available on the platform. 5216 5217 jlong os::current_thread_cpu_time() { 5218 if (os::Linux::supports_fast_thread_cpu_time()) { 5219 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5220 } else { 5221 // return user + sys since the cost is the same 5222 return slow_thread_cpu_time(Thread::current(), true /* user + sys */); 5223 } 5224 } 5225 5226 jlong os::thread_cpu_time(Thread* thread) { 5227 // consistent with what current_thread_cpu_time() returns 5228 if (os::Linux::supports_fast_thread_cpu_time()) { 5229 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5230 } else { 5231 return slow_thread_cpu_time(thread, true /* user + sys */); 5232 } 5233 } 5234 5235 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) { 5236 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5237 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID); 5238 } else { 5239 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time); 5240 } 5241 } 5242 5243 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5244 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) { 5245 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread)); 5246 } else { 5247 return slow_thread_cpu_time(thread, user_sys_cpu_time); 5248 } 5249 } 5250 5251 // -1 on error. 5252 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) { 5253 pid_t tid = thread->osthread()->thread_id(); 5254 char *s; 5255 char stat[2048]; 5256 int statlen; 5257 char proc_name[64]; 5258 int count; 5259 long sys_time, user_time; 5260 char cdummy; 5261 int idummy; 5262 long ldummy; 5263 FILE *fp; 5264 5265 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid); 5266 fp = fopen(proc_name, "r"); 5267 if (fp == NULL) return -1; 5268 statlen = fread(stat, 1, 2047, fp); 5269 stat[statlen] = '\0'; 5270 fclose(fp); 5271 5272 // Skip pid and the command string. Note that we could be dealing with 5273 // weird command names, e.g. user could decide to rename java launcher 5274 // to "java 1.4.2 :)", then the stat file would look like 5275 // 1234 (java 1.4.2 :)) R ... ... 5276 // We don't really need to know the command string, just find the last 5277 // occurrence of ")" and then start parsing from there. See bug 4726580. 5278 s = strrchr(stat, ')'); 5279 if (s == NULL) return -1; 5280 5281 // Skip blank chars 5282 do { s++; } while (s && isspace(*s)); 5283 5284 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu", 5285 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy, 5286 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy, 5287 &user_time, &sys_time); 5288 if (count != 13) return -1; 5289 if (user_sys_cpu_time) { 5290 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec); 5291 } else { 5292 return (jlong)user_time * (1000000000 / clock_tics_per_sec); 5293 } 5294 } 5295 5296 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5297 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5298 info_ptr->may_skip_backward = false; // elapsed time not wall time 5299 info_ptr->may_skip_forward = false; // elapsed time not wall time 5300 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5301 } 5302 5303 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) { 5304 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits 5305 info_ptr->may_skip_backward = false; // elapsed time not wall time 5306 info_ptr->may_skip_forward = false; // elapsed time not wall time 5307 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned 5308 } 5309 5310 bool os::is_thread_cpu_time_supported() { 5311 return true; 5312 } 5313 5314 // System loadavg support. Returns -1 if load average cannot be obtained. 5315 // Linux doesn't yet have a (official) notion of processor sets, 5316 // so just return the system wide load average. 5317 int os::loadavg(double loadavg[], int nelem) { 5318 return ::getloadavg(loadavg, nelem); 5319 } 5320 5321 void os::pause() { 5322 char filename[MAX_PATH]; 5323 if (PauseAtStartupFile && PauseAtStartupFile[0]) { 5324 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile); 5325 } else { 5326 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id()); 5327 } 5328 5329 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666); 5330 if (fd != -1) { 5331 struct stat buf; 5332 ::close(fd); 5333 while (::stat(filename, &buf) == 0) { 5334 (void)::poll(NULL, 0, 100); 5335 } 5336 } else { 5337 jio_fprintf(stderr, 5338 "Could not open pause file '%s', continuing immediately.\n", filename); 5339 } 5340 } 5341 5342 5343 // Refer to the comments in os_solaris.cpp park-unpark. The next two 5344 // comment paragraphs are worth repeating here: 5345 // 5346 // Assumption: 5347 // Only one parker can exist on an event, which is why we allocate 5348 // them per-thread. Multiple unparkers can coexist. 5349 // 5350 // _Event serves as a restricted-range semaphore. 5351 // -1 : thread is blocked, i.e. there is a waiter 5352 // 0 : neutral: thread is running or ready, 5353 // could have been signaled after a wait started 5354 // 1 : signaled - thread is running or ready 5355 // 5356 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can 5357 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable. 5358 // For specifics regarding the bug see GLIBC BUGID 261237 : 5359 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html. 5360 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future 5361 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar 5362 // is used. (The simple C test-case provided in the GLIBC bug report manifests the 5363 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos() 5364 // and monitorenter when we're using 1-0 locking. All those operations may result in 5365 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version 5366 // of libpthread avoids the problem, but isn't practical. 5367 // 5368 // Possible remedies: 5369 // 5370 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work. 5371 // This is palliative and probabilistic, however. If the thread is preempted 5372 // between the call to compute_abstime() and pthread_cond_timedwait(), more 5373 // than the minimum period may have passed, and the abstime may be stale (in the 5374 // past) resultin in a hang. Using this technique reduces the odds of a hang 5375 // but the JVM is still vulnerable, particularly on heavily loaded systems. 5376 // 5377 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead 5378 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set 5379 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo) 5380 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant 5381 // thread. 5382 // 5383 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread 5384 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing 5385 // a timeout request to the chron thread and then blocking via pthread_cond_wait(). 5386 // This also works well. In fact it avoids kernel-level scalability impediments 5387 // on certain platforms that don't handle lots of active pthread_cond_timedwait() 5388 // timers in a graceful fashion. 5389 // 5390 // 4. When the abstime value is in the past it appears that control returns 5391 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt. 5392 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we 5393 // can avoid the problem by reinitializing the condvar -- by cond_destroy() 5394 // followed by cond_init() -- after all calls to pthread_cond_timedwait(). 5395 // It may be possible to avoid reinitialization by checking the return 5396 // value from pthread_cond_timedwait(). In addition to reinitializing the 5397 // condvar we must establish the invariant that cond_signal() is only called 5398 // within critical sections protected by the adjunct mutex. This prevents 5399 // cond_signal() from "seeing" a condvar that's in the midst of being 5400 // reinitialized or that is corrupt. Sadly, this invariant obviates the 5401 // desirable signal-after-unlock optimization that avoids futile context switching. 5402 // 5403 // I'm also concerned that some versions of NTPL might allocate an auxilliary 5404 // structure when a condvar is used or initialized. cond_destroy() would 5405 // release the helper structure. Our reinitialize-after-timedwait fix 5406 // put excessive stress on malloc/free and locks protecting the c-heap. 5407 // 5408 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag. 5409 // It may be possible to refine (4) by checking the kernel and NTPL verisons 5410 // and only enabling the work-around for vulnerable environments. 5411 5412 // utility to compute the abstime argument to timedwait: 5413 // millis is the relative timeout time 5414 // abstime will be the absolute timeout time 5415 // TODO: replace compute_abstime() with unpackTime() 5416 5417 static struct timespec* compute_abstime(timespec* abstime, jlong millis) { 5418 if (millis < 0) millis = 0; 5419 5420 jlong seconds = millis / 1000; 5421 millis %= 1000; 5422 if (seconds > 50000000) { // see man cond_timedwait(3T) 5423 seconds = 50000000; 5424 } 5425 5426 if (os::supports_monotonic_clock()) { 5427 struct timespec now; 5428 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5429 assert_status(status == 0, status, "clock_gettime"); 5430 abstime->tv_sec = now.tv_sec + seconds; 5431 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC; 5432 if (nanos >= NANOSECS_PER_SEC) { 5433 abstime->tv_sec += 1; 5434 nanos -= NANOSECS_PER_SEC; 5435 } 5436 abstime->tv_nsec = nanos; 5437 } else { 5438 struct timeval now; 5439 int status = gettimeofday(&now, NULL); 5440 assert(status == 0, "gettimeofday"); 5441 abstime->tv_sec = now.tv_sec + seconds; 5442 long usec = now.tv_usec + millis * 1000; 5443 if (usec >= 1000000) { 5444 abstime->tv_sec += 1; 5445 usec -= 1000000; 5446 } 5447 abstime->tv_nsec = usec * 1000; 5448 } 5449 return abstime; 5450 } 5451 5452 void os::PlatformEvent::park() { // AKA "down()" 5453 // Transitions for _Event: 5454 // -1 => -1 : illegal 5455 // 1 => 0 : pass - return immediately 5456 // 0 => -1 : block; then set _Event to 0 before returning 5457 5458 // Invariant: Only the thread associated with the Event/PlatformEvent 5459 // may call park(). 5460 // TODO: assert that _Assoc != NULL or _Assoc == Self 5461 assert(_nParked == 0, "invariant"); 5462 5463 int v; 5464 for (;;) { 5465 v = _Event; 5466 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5467 } 5468 guarantee(v >= 0, "invariant"); 5469 if (v == 0) { 5470 // Do this the hard way by blocking ... 5471 int status = pthread_mutex_lock(_mutex); 5472 assert_status(status == 0, status, "mutex_lock"); 5473 guarantee(_nParked == 0, "invariant"); 5474 ++_nParked; 5475 while (_Event < 0) { 5476 status = pthread_cond_wait(_cond, _mutex); 5477 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ... 5478 // Treat this the same as if the wait was interrupted 5479 if (status == ETIME) { status = EINTR; } 5480 assert_status(status == 0 || status == EINTR, status, "cond_wait"); 5481 } 5482 --_nParked; 5483 5484 _Event = 0; 5485 status = pthread_mutex_unlock(_mutex); 5486 assert_status(status == 0, status, "mutex_unlock"); 5487 // Paranoia to ensure our locked and lock-free paths interact 5488 // correctly with each other. 5489 OrderAccess::fence(); 5490 } 5491 guarantee(_Event >= 0, "invariant"); 5492 } 5493 5494 int os::PlatformEvent::park(jlong millis) { 5495 // Transitions for _Event: 5496 // -1 => -1 : illegal 5497 // 1 => 0 : pass - return immediately 5498 // 0 => -1 : block; then set _Event to 0 before returning 5499 5500 guarantee(_nParked == 0, "invariant"); 5501 5502 int v; 5503 for (;;) { 5504 v = _Event; 5505 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break; 5506 } 5507 guarantee(v >= 0, "invariant"); 5508 if (v != 0) return OS_OK; 5509 5510 // We do this the hard way, by blocking the thread. 5511 // Consider enforcing a minimum timeout value. 5512 struct timespec abst; 5513 compute_abstime(&abst, millis); 5514 5515 int ret = OS_TIMEOUT; 5516 int status = pthread_mutex_lock(_mutex); 5517 assert_status(status == 0, status, "mutex_lock"); 5518 guarantee(_nParked == 0, "invariant"); 5519 ++_nParked; 5520 5521 // Object.wait(timo) will return because of 5522 // (a) notification 5523 // (b) timeout 5524 // (c) thread.interrupt 5525 // 5526 // Thread.interrupt and object.notify{All} both call Event::set. 5527 // That is, we treat thread.interrupt as a special case of notification. 5528 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false. 5529 // We assume all ETIME returns are valid. 5530 // 5531 // TODO: properly differentiate simultaneous notify+interrupt. 5532 // In that case, we should propagate the notify to another waiter. 5533 5534 while (_Event < 0) { 5535 status = pthread_cond_timedwait(_cond, _mutex, &abst); 5536 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5537 pthread_cond_destroy(_cond); 5538 pthread_cond_init(_cond, os::Linux::condAttr()); 5539 } 5540 assert_status(status == 0 || status == EINTR || 5541 status == ETIME || status == ETIMEDOUT, 5542 status, "cond_timedwait"); 5543 if (!FilterSpuriousWakeups) break; // previous semantics 5544 if (status == ETIME || status == ETIMEDOUT) break; 5545 // We consume and ignore EINTR and spurious wakeups. 5546 } 5547 --_nParked; 5548 if (_Event >= 0) { 5549 ret = OS_OK; 5550 } 5551 _Event = 0; 5552 status = pthread_mutex_unlock(_mutex); 5553 assert_status(status == 0, status, "mutex_unlock"); 5554 assert(_nParked == 0, "invariant"); 5555 // Paranoia to ensure our locked and lock-free paths interact 5556 // correctly with each other. 5557 OrderAccess::fence(); 5558 return ret; 5559 } 5560 5561 void os::PlatformEvent::unpark() { 5562 // Transitions for _Event: 5563 // 0 => 1 : just return 5564 // 1 => 1 : just return 5565 // -1 => either 0 or 1; must signal target thread 5566 // That is, we can safely transition _Event from -1 to either 5567 // 0 or 1. 5568 // See also: "Semaphores in Plan 9" by Mullender & Cox 5569 // 5570 // Note: Forcing a transition from "-1" to "1" on an unpark() means 5571 // that it will take two back-to-back park() calls for the owning 5572 // thread to block. This has the benefit of forcing a spurious return 5573 // from the first park() call after an unpark() call which will help 5574 // shake out uses of park() and unpark() without condition variables. 5575 5576 if (Atomic::xchg(1, &_Event) >= 0) return; 5577 5578 // Wait for the thread associated with the event to vacate 5579 int status = pthread_mutex_lock(_mutex); 5580 assert_status(status == 0, status, "mutex_lock"); 5581 int AnyWaiters = _nParked; 5582 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant"); 5583 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) { 5584 AnyWaiters = 0; 5585 pthread_cond_signal(_cond); 5586 } 5587 status = pthread_mutex_unlock(_mutex); 5588 assert_status(status == 0, status, "mutex_unlock"); 5589 if (AnyWaiters != 0) { 5590 // Note that we signal() *after* dropping the lock for "immortal" Events. 5591 // This is safe and avoids a common class of futile wakeups. In rare 5592 // circumstances this can cause a thread to return prematurely from 5593 // cond_{timed}wait() but the spurious wakeup is benign and the victim 5594 // will simply re-test the condition and re-park itself. 5595 // This provides particular benefit if the underlying platform does not 5596 // provide wait morphing. 5597 status = pthread_cond_signal(_cond); 5598 assert_status(status == 0, status, "cond_signal"); 5599 } 5600 } 5601 5602 5603 // JSR166 5604 // ------------------------------------------------------- 5605 5606 // The solaris and linux implementations of park/unpark are fairly 5607 // conservative for now, but can be improved. They currently use a 5608 // mutex/condvar pair, plus a a count. 5609 // Park decrements count if > 0, else does a condvar wait. Unpark 5610 // sets count to 1 and signals condvar. Only one thread ever waits 5611 // on the condvar. Contention seen when trying to park implies that someone 5612 // is unparking you, so don't wait. And spurious returns are fine, so there 5613 // is no need to track notifications. 5614 5615 // This code is common to linux and solaris and will be moved to a 5616 // common place in dolphin. 5617 // 5618 // The passed in time value is either a relative time in nanoseconds 5619 // or an absolute time in milliseconds. Either way it has to be unpacked 5620 // into suitable seconds and nanoseconds components and stored in the 5621 // given timespec structure. 5622 // Given time is a 64-bit value and the time_t used in the timespec is only 5623 // a signed-32-bit value (except on 64-bit Linux) we have to watch for 5624 // overflow if times way in the future are given. Further on Solaris versions 5625 // prior to 10 there is a restriction (see cond_timedwait) that the specified 5626 // number of seconds, in abstime, is less than current_time + 100,000,000. 5627 // As it will be 28 years before "now + 100000000" will overflow we can 5628 // ignore overflow and just impose a hard-limit on seconds using the value 5629 // of "now + 100,000,000". This places a limit on the timeout of about 3.17 5630 // years from "now". 5631 5632 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) { 5633 assert(time > 0, "convertTime"); 5634 time_t max_secs = 0; 5635 5636 if (!os::supports_monotonic_clock() || isAbsolute) { 5637 struct timeval now; 5638 int status = gettimeofday(&now, NULL); 5639 assert(status == 0, "gettimeofday"); 5640 5641 max_secs = now.tv_sec + MAX_SECS; 5642 5643 if (isAbsolute) { 5644 jlong secs = time / 1000; 5645 if (secs > max_secs) { 5646 absTime->tv_sec = max_secs; 5647 } else { 5648 absTime->tv_sec = secs; 5649 } 5650 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC; 5651 } else { 5652 jlong secs = time / NANOSECS_PER_SEC; 5653 if (secs >= MAX_SECS) { 5654 absTime->tv_sec = max_secs; 5655 absTime->tv_nsec = 0; 5656 } else { 5657 absTime->tv_sec = now.tv_sec + secs; 5658 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000; 5659 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5660 absTime->tv_nsec -= NANOSECS_PER_SEC; 5661 ++absTime->tv_sec; // note: this must be <= max_secs 5662 } 5663 } 5664 } 5665 } else { 5666 // must be relative using monotonic clock 5667 struct timespec now; 5668 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now); 5669 assert_status(status == 0, status, "clock_gettime"); 5670 max_secs = now.tv_sec + MAX_SECS; 5671 jlong secs = time / NANOSECS_PER_SEC; 5672 if (secs >= MAX_SECS) { 5673 absTime->tv_sec = max_secs; 5674 absTime->tv_nsec = 0; 5675 } else { 5676 absTime->tv_sec = now.tv_sec + secs; 5677 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec; 5678 if (absTime->tv_nsec >= NANOSECS_PER_SEC) { 5679 absTime->tv_nsec -= NANOSECS_PER_SEC; 5680 ++absTime->tv_sec; // note: this must be <= max_secs 5681 } 5682 } 5683 } 5684 assert(absTime->tv_sec >= 0, "tv_sec < 0"); 5685 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs"); 5686 assert(absTime->tv_nsec >= 0, "tv_nsec < 0"); 5687 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec"); 5688 } 5689 5690 void Parker::park(bool isAbsolute, jlong time) { 5691 // Ideally we'd do something useful while spinning, such 5692 // as calling unpackTime(). 5693 5694 // Optional fast-path check: 5695 // Return immediately if a permit is available. 5696 // We depend on Atomic::xchg() having full barrier semantics 5697 // since we are doing a lock-free update to _counter. 5698 if (Atomic::xchg(0, &_counter) > 0) return; 5699 5700 Thread* thread = Thread::current(); 5701 assert(thread->is_Java_thread(), "Must be JavaThread"); 5702 JavaThread *jt = (JavaThread *)thread; 5703 5704 // Optional optimization -- avoid state transitions if there's an interrupt pending. 5705 // Check interrupt before trying to wait 5706 if (Thread::is_interrupted(thread, false)) { 5707 return; 5708 } 5709 5710 // Next, demultiplex/decode time arguments 5711 timespec absTime; 5712 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all 5713 return; 5714 } 5715 if (time > 0) { 5716 unpackTime(&absTime, isAbsolute, time); 5717 } 5718 5719 5720 // Enter safepoint region 5721 // Beware of deadlocks such as 6317397. 5722 // The per-thread Parker:: mutex is a classic leaf-lock. 5723 // In particular a thread must never block on the Threads_lock while 5724 // holding the Parker:: mutex. If safepoints are pending both the 5725 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock. 5726 ThreadBlockInVM tbivm(jt); 5727 5728 // Don't wait if cannot get lock since interference arises from 5729 // unblocking. Also. check interrupt before trying wait 5730 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) { 5731 return; 5732 } 5733 5734 int status; 5735 if (_counter > 0) { // no wait needed 5736 _counter = 0; 5737 status = pthread_mutex_unlock(_mutex); 5738 assert(status == 0, "invariant"); 5739 // Paranoia to ensure our locked and lock-free paths interact 5740 // correctly with each other and Java-level accesses. 5741 OrderAccess::fence(); 5742 return; 5743 } 5744 5745 #ifdef ASSERT 5746 // Don't catch signals while blocked; let the running threads have the signals. 5747 // (This allows a debugger to break into the running thread.) 5748 sigset_t oldsigs; 5749 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals(); 5750 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs); 5751 #endif 5752 5753 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); 5754 jt->set_suspend_equivalent(); 5755 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() 5756 5757 assert(_cur_index == -1, "invariant"); 5758 if (time == 0) { 5759 _cur_index = REL_INDEX; // arbitrary choice when not timed 5760 status = pthread_cond_wait(&_cond[_cur_index], _mutex); 5761 } else { 5762 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; 5763 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); 5764 if (status != 0 && WorkAroundNPTLTimedWaitHang) { 5765 pthread_cond_destroy(&_cond[_cur_index]); 5766 pthread_cond_init(&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr()); 5767 } 5768 } 5769 _cur_index = -1; 5770 assert_status(status == 0 || status == EINTR || 5771 status == ETIME || status == ETIMEDOUT, 5772 status, "cond_timedwait"); 5773 5774 #ifdef ASSERT 5775 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL); 5776 #endif 5777 5778 _counter = 0; 5779 status = pthread_mutex_unlock(_mutex); 5780 assert_status(status == 0, status, "invariant"); 5781 // Paranoia to ensure our locked and lock-free paths interact 5782 // correctly with each other and Java-level accesses. 5783 OrderAccess::fence(); 5784 5785 // If externally suspended while waiting, re-suspend 5786 if (jt->handle_special_suspend_equivalent_condition()) { 5787 jt->java_suspend_self(); 5788 } 5789 } 5790 5791 void Parker::unpark() { 5792 int status = pthread_mutex_lock(_mutex); 5793 assert(status == 0, "invariant"); 5794 const int s = _counter; 5795 _counter = 1; 5796 if (s < 1) { 5797 // thread might be parked 5798 if (_cur_index != -1) { 5799 // thread is definitely parked 5800 if (WorkAroundNPTLTimedWaitHang) { 5801 status = pthread_cond_signal(&_cond[_cur_index]); 5802 assert(status == 0, "invariant"); 5803 status = pthread_mutex_unlock(_mutex); 5804 assert(status == 0, "invariant"); 5805 } else { 5806 // must capture correct index before unlocking 5807 int index = _cur_index; 5808 status = pthread_mutex_unlock(_mutex); 5809 assert(status == 0, "invariant"); 5810 status = pthread_cond_signal(&_cond[index]); 5811 assert(status == 0, "invariant"); 5812 } 5813 } else { 5814 pthread_mutex_unlock(_mutex); 5815 assert(status == 0, "invariant"); 5816 } 5817 } else { 5818 pthread_mutex_unlock(_mutex); 5819 assert(status == 0, "invariant"); 5820 } 5821 } 5822 5823 5824 extern char** environ; 5825 5826 // Run the specified command in a separate process. Return its exit value, 5827 // or -1 on failure (e.g. can't fork a new process). 5828 // Unlike system(), this function can be called from signal handler. It 5829 // doesn't block SIGINT et al. 5830 int os::fork_and_exec(char* cmd) { 5831 const char * argv[4] = {"sh", "-c", cmd, NULL}; 5832 5833 pid_t pid = fork(); 5834 5835 if (pid < 0) { 5836 // fork failed 5837 return -1; 5838 5839 } else if (pid == 0) { 5840 // child process 5841 5842 execve("/bin/sh", (char* const*)argv, environ); 5843 5844 // execve failed 5845 _exit(-1); 5846 5847 } else { 5848 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't 5849 // care about the actual exit code, for now. 5850 5851 int status; 5852 5853 // Wait for the child process to exit. This returns immediately if 5854 // the child has already exited. */ 5855 while (waitpid(pid, &status, 0) < 0) { 5856 switch (errno) { 5857 case ECHILD: return 0; 5858 case EINTR: break; 5859 default: return -1; 5860 } 5861 } 5862 5863 if (WIFEXITED(status)) { 5864 // The child exited normally; get its exit code. 5865 return WEXITSTATUS(status); 5866 } else if (WIFSIGNALED(status)) { 5867 // The child exited because of a signal 5868 // The best value to return is 0x80 + signal number, 5869 // because that is what all Unix shells do, and because 5870 // it allows callers to distinguish between process exit and 5871 // process death by signal. 5872 return 0x80 + WTERMSIG(status); 5873 } else { 5874 // Unknown exit code; pass it through 5875 return status; 5876 } 5877 } 5878 } 5879 5880 // is_headless_jre() 5881 // 5882 // Test for the existence of xawt/libmawt.so or libawt_xawt.so 5883 // in order to report if we are running in a headless jre 5884 // 5885 // Since JDK8 xawt/libmawt.so was moved into the same directory 5886 // as libawt.so, and renamed libawt_xawt.so 5887 // 5888 bool os::is_headless_jre() { 5889 struct stat statbuf; 5890 char buf[MAXPATHLEN]; 5891 char libmawtpath[MAXPATHLEN]; 5892 const char *xawtstr = "/xawt/libmawt.so"; 5893 const char *new_xawtstr = "/libawt_xawt.so"; 5894 char *p; 5895 5896 // Get path to libjvm.so 5897 os::jvm_path(buf, sizeof(buf)); 5898 5899 // Get rid of libjvm.so 5900 p = strrchr(buf, '/'); 5901 if (p == NULL) { 5902 return false; 5903 } else { 5904 *p = '\0'; 5905 } 5906 5907 // Get rid of client or server 5908 p = strrchr(buf, '/'); 5909 if (p == NULL) { 5910 return false; 5911 } else { 5912 *p = '\0'; 5913 } 5914 5915 // check xawt/libmawt.so 5916 strcpy(libmawtpath, buf); 5917 strcat(libmawtpath, xawtstr); 5918 if (::stat(libmawtpath, &statbuf) == 0) return false; 5919 5920 // check libawt_xawt.so 5921 strcpy(libmawtpath, buf); 5922 strcat(libmawtpath, new_xawtstr); 5923 if (::stat(libmawtpath, &statbuf) == 0) return false; 5924 5925 return true; 5926 } 5927 5928 // Get the default path to the core file 5929 // Returns the length of the string 5930 int os::get_core_path(char* buffer, size_t bufferSize) { 5931 /* 5932 * Max length of /proc/sys/kernel/core_pattern is 128 characters. 5933 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt 5934 */ 5935 const int core_pattern_len = 129; 5936 char core_pattern[core_pattern_len] = {0}; 5937 5938 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY); 5939 if (core_pattern_file == -1) { 5940 return -1; 5941 } 5942 5943 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len); 5944 ::close(core_pattern_file); 5945 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') { 5946 return -1; 5947 } 5948 if (core_pattern[ret-1] == '\n') { 5949 core_pattern[ret-1] = '\0'; 5950 } else { 5951 core_pattern[ret] = '\0'; 5952 } 5953 5954 char *pid_pos = strstr(core_pattern, "%p"); 5955 int written; 5956 5957 if (core_pattern[0] == '/') { 5958 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern); 5959 } else { 5960 char cwd[PATH_MAX]; 5961 5962 const char* p = get_current_directory(cwd, PATH_MAX); 5963 if (p == NULL) { 5964 return -1; 5965 } 5966 5967 if (core_pattern[0] == '|') { 5968 written = jio_snprintf(buffer, bufferSize, 5969 "\"%s\" (or dumping to %s/core.%d)", 5970 &core_pattern[1], p, current_process_id()); 5971 } else { 5972 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern); 5973 } 5974 } 5975 5976 if (written < 0) { 5977 return -1; 5978 } 5979 5980 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) { 5981 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY); 5982 5983 if (core_uses_pid_file != -1) { 5984 char core_uses_pid = 0; 5985 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1); 5986 ::close(core_uses_pid_file); 5987 5988 if (core_uses_pid == '1') { 5989 jio_snprintf(buffer + written, bufferSize - written, 5990 ".%d", current_process_id()); 5991 } 5992 } 5993 } 5994 5995 return strlen(buffer); 5996 } 5997 5998 bool os::start_debugging(char *buf, int buflen) { 5999 int len = (int)strlen(buf); 6000 char *p = &buf[len]; 6001 6002 jio_snprintf(p, buflen-len, 6003 "\n\n" 6004 "Do you want to debug the problem?\n\n" 6005 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n" 6006 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n" 6007 "Otherwise, press RETURN to abort...", 6008 os::current_process_id(), os::current_process_id(), 6009 os::current_thread_id(), os::current_thread_id()); 6010 6011 bool yes = os::message_box("Unexpected Error", buf); 6012 6013 if (yes) { 6014 // yes, user asked VM to launch debugger 6015 jio_snprintf(buf, sizeof(buf), "gdb /proc/%d/exe %d", 6016 os::current_process_id(), os::current_process_id()); 6017 6018 os::fork_and_exec(buf); 6019 yes = false; 6020 } 6021 return yes; 6022 } 6023 6024 6025 6026 /////////////// Unit tests /////////////// 6027 6028 #ifndef PRODUCT 6029 6030 #define test_log(...) \ 6031 do { \ 6032 if (VerboseInternalVMTests) { \ 6033 tty->print_cr(__VA_ARGS__); \ 6034 tty->flush(); \ 6035 } \ 6036 } while (false) 6037 6038 class TestReserveMemorySpecial : AllStatic { 6039 public: 6040 static void small_page_write(void* addr, size_t size) { 6041 size_t page_size = os::vm_page_size(); 6042 6043 char* end = (char*)addr + size; 6044 for (char* p = (char*)addr; p < end; p += page_size) { 6045 *p = 1; 6046 } 6047 } 6048 6049 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) { 6050 if (!UseHugeTLBFS) { 6051 return; 6052 } 6053 6054 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size); 6055 6056 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false); 6057 6058 if (addr != NULL) { 6059 small_page_write(addr, size); 6060 6061 os::Linux::release_memory_special_huge_tlbfs(addr, size); 6062 } 6063 } 6064 6065 static void test_reserve_memory_special_huge_tlbfs_only() { 6066 if (!UseHugeTLBFS) { 6067 return; 6068 } 6069 6070 size_t lp = os::large_page_size(); 6071 6072 for (size_t size = lp; size <= lp * 10; size += lp) { 6073 test_reserve_memory_special_huge_tlbfs_only(size); 6074 } 6075 } 6076 6077 static void test_reserve_memory_special_huge_tlbfs_mixed() { 6078 size_t lp = os::large_page_size(); 6079 size_t ag = os::vm_allocation_granularity(); 6080 6081 // sizes to test 6082 const size_t sizes[] = { 6083 lp, lp + ag, lp + lp / 2, lp * 2, 6084 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2, 6085 lp * 10, lp * 10 + lp / 2 6086 }; 6087 const int num_sizes = sizeof(sizes) / sizeof(size_t); 6088 6089 // For each size/alignment combination, we test three scenarios: 6090 // 1) with req_addr == NULL 6091 // 2) with a non-null req_addr at which we expect to successfully allocate 6092 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we 6093 // expect the allocation to either fail or to ignore req_addr 6094 6095 // Pre-allocate two areas; they shall be as large as the largest allocation 6096 // and aligned to the largest alignment we will be testing. 6097 const size_t mapping_size = sizes[num_sizes - 1] * 2; 6098 char* const mapping1 = (char*) ::mmap(NULL, mapping_size, 6099 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6100 -1, 0); 6101 assert(mapping1 != MAP_FAILED, "should work"); 6102 6103 char* const mapping2 = (char*) ::mmap(NULL, mapping_size, 6104 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE, 6105 -1, 0); 6106 assert(mapping2 != MAP_FAILED, "should work"); 6107 6108 // Unmap the first mapping, but leave the second mapping intact: the first 6109 // mapping will serve as a value for a "good" req_addr (case 2). The second 6110 // mapping, still intact, as "bad" req_addr (case 3). 6111 ::munmap(mapping1, mapping_size); 6112 6113 // Case 1 6114 test_log("%s, req_addr NULL:", __FUNCTION__); 6115 test_log("size align result"); 6116 6117 for (int i = 0; i < num_sizes; i++) { 6118 const size_t size = sizes[i]; 6119 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6120 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false); 6121 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s", 6122 size, alignment, p2i(p), (p != NULL ? "" : "(failed)")); 6123 if (p != NULL) { 6124 assert(is_ptr_aligned(p, alignment), "must be"); 6125 small_page_write(p, size); 6126 os::Linux::release_memory_special_huge_tlbfs(p, size); 6127 } 6128 } 6129 } 6130 6131 // Case 2 6132 test_log("%s, req_addr non-NULL:", __FUNCTION__); 6133 test_log("size align req_addr result"); 6134 6135 for (int i = 0; i < num_sizes; i++) { 6136 const size_t size = sizes[i]; 6137 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6138 char* const req_addr = (char*) align_ptr_up(mapping1, alignment); 6139 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6140 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6141 size, alignment, p2i(req_addr), p2i(p), 6142 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)"))); 6143 if (p != NULL) { 6144 assert(p == req_addr, "must be"); 6145 small_page_write(p, size); 6146 os::Linux::release_memory_special_huge_tlbfs(p, size); 6147 } 6148 } 6149 } 6150 6151 // Case 3 6152 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__); 6153 test_log("size align req_addr result"); 6154 6155 for (int i = 0; i < num_sizes; i++) { 6156 const size_t size = sizes[i]; 6157 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6158 char* const req_addr = (char*) align_ptr_up(mapping2, alignment); 6159 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false); 6160 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s", 6161 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)"))); 6162 // as the area around req_addr contains already existing mappings, the API should always 6163 // return NULL (as per contract, it cannot return another address) 6164 assert(p == NULL, "must be"); 6165 } 6166 } 6167 6168 ::munmap(mapping2, mapping_size); 6169 6170 } 6171 6172 static void test_reserve_memory_special_huge_tlbfs() { 6173 if (!UseHugeTLBFS) { 6174 return; 6175 } 6176 6177 test_reserve_memory_special_huge_tlbfs_only(); 6178 test_reserve_memory_special_huge_tlbfs_mixed(); 6179 } 6180 6181 static void test_reserve_memory_special_shm(size_t size, size_t alignment) { 6182 if (!UseSHM) { 6183 return; 6184 } 6185 6186 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment); 6187 6188 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false); 6189 6190 if (addr != NULL) { 6191 assert(is_ptr_aligned(addr, alignment), "Check"); 6192 assert(is_ptr_aligned(addr, os::large_page_size()), "Check"); 6193 6194 small_page_write(addr, size); 6195 6196 os::Linux::release_memory_special_shm(addr, size); 6197 } 6198 } 6199 6200 static void test_reserve_memory_special_shm() { 6201 size_t lp = os::large_page_size(); 6202 size_t ag = os::vm_allocation_granularity(); 6203 6204 for (size_t size = ag; size < lp * 3; size += ag) { 6205 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) { 6206 test_reserve_memory_special_shm(size, alignment); 6207 } 6208 } 6209 } 6210 6211 static void test() { 6212 test_reserve_memory_special_huge_tlbfs(); 6213 test_reserve_memory_special_shm(); 6214 } 6215 }; 6216 6217 void TestReserveMemorySpecial_test() { 6218 TestReserveMemorySpecial::test(); 6219 } 6220 6221 #endif