1 /*
2 * Copyright (c) 1999, 2020, 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 "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/disassembler.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/filemap.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_linux.inline.hpp"
41 #include "os_posix.inline.hpp"
42 #include "os_share_linux.hpp"
43 #include "osContainer_linux.hpp"
44 #include "prims/jniFastGetField.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/atomic.hpp"
48 #include "runtime/extendedPC.hpp"
49 #include "runtime/globals.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "runtime/init.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/objectMonitor.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/perfMemory.hpp"
58 #include "runtime/sharedRuntime.hpp"
59 #include "runtime/statSampler.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/thread.inline.hpp"
62 #include "runtime/threadCritical.hpp"
63 #include "runtime/threadSMR.hpp"
64 #include "runtime/timer.hpp"
65 #include "runtime/vm_version.hpp"
66 #include "semaphore_posix.hpp"
67 #include "services/attachListener.hpp"
68 #include "services/memTracker.hpp"
69 #include "services/runtimeService.hpp"
70 #include "utilities/align.hpp"
71 #include "utilities/decoder.hpp"
72 #include "utilities/defaultStream.hpp"
73 #include "utilities/events.hpp"
74 #include "utilities/elfFile.hpp"
75 #include "utilities/growableArray.hpp"
76 #include "utilities/macros.hpp"
77 #include "utilities/powerOfTwo.hpp"
78 #include "utilities/vmError.hpp"
79
80 // put OS-includes here
81 # include <sys/types.h>
82 # include <sys/mman.h>
83 # include <sys/stat.h>
84 # include <sys/select.h>
85 # include <pthread.h>
86 # include <signal.h>
87 # include <endian.h>
88 # include <errno.h>
89 # include <dlfcn.h>
90 # include <stdio.h>
91 # include <unistd.h>
92 # include <sys/resource.h>
93 # include <pthread.h>
94 # include <sys/stat.h>
95 # include <sys/time.h>
96 # include <sys/times.h>
97 # include <sys/utsname.h>
98 # include <sys/socket.h>
99 # include <sys/wait.h>
100 # include <pwd.h>
101 # include <poll.h>
102 # include <fcntl.h>
103 # include <string.h>
104 # include <syscall.h>
105 # include <sys/sysinfo.h>
106 # include <gnu/libc-version.h>
107 # include <sys/ipc.h>
108 # include <sys/shm.h>
109 # include <link.h>
110 # include <stdint.h>
111 # include <inttypes.h>
112 # include <sys/ioctl.h>
113 # include <linux/elf-em.h>
114
115 #ifndef _GNU_SOURCE
116 #define _GNU_SOURCE
117 #include <sched.h>
118 #undef _GNU_SOURCE
119 #else
120 #include <sched.h>
121 #endif
122
123 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
124 // getrusage() is prepared to handle the associated failure.
125 #ifndef RUSAGE_THREAD
126 #define RUSAGE_THREAD (1) /* only the calling thread */
127 #endif
128
129 #define MAX_PATH (2 * K)
130
131 #define MAX_SECS 100000000
132
133 // for timer info max values which include all bits
134 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
135
136 enum CoredumpFilterBit {
137 FILE_BACKED_PVT_BIT = 1 << 2,
138 FILE_BACKED_SHARED_BIT = 1 << 3,
139 LARGEPAGES_BIT = 1 << 6,
140 DAX_SHARED_BIT = 1 << 8
141 };
142
143 ////////////////////////////////////////////////////////////////////////////////
144 // global variables
145 julong os::Linux::_physical_memory = 0;
146
147 address os::Linux::_initial_thread_stack_bottom = NULL;
148 uintptr_t os::Linux::_initial_thread_stack_size = 0;
149
150 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
151 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
152 pthread_t os::Linux::_main_thread;
153 int os::Linux::_page_size = -1;
154 bool os::Linux::_supports_fast_thread_cpu_time = false;
155 const char * os::Linux::_glibc_version = NULL;
156 const char * os::Linux::_libpthread_version = NULL;
157
158 static jlong initial_time_count=0;
159
160 static int clock_tics_per_sec = 100;
161
162 // If the VM might have been created on the primordial thread, we need to resolve the
163 // primordial thread stack bounds and check if the current thread might be the
164 // primordial thread in places. If we know that the primordial thread is never used,
165 // such as when the VM was created by one of the standard java launchers, we can
166 // avoid this
167 static bool suppress_primordial_thread_resolution = false;
168
169 // For diagnostics to print a message once. see run_periodic_checks
170 static sigset_t check_signal_done;
171 static bool check_signals = true;
172
173 // Signal number used to suspend/resume a thread
174
175 // do not use any signal number less than SIGSEGV, see 4355769
176 static int SR_signum = SIGUSR2;
177 sigset_t SR_sigset;
178
179 // utility functions
180
181 static int SR_initialize();
182
183 julong os::available_memory() {
184 return Linux::available_memory();
185 }
186
187 julong os::Linux::available_memory() {
188 // values in struct sysinfo are "unsigned long"
189 struct sysinfo si;
190 julong avail_mem;
191
192 if (OSContainer::is_containerized()) {
193 jlong mem_limit, mem_usage;
194 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
195 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
196 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
197 }
198 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
199 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
200 }
201 if (mem_limit > 0 && mem_usage > 0 ) {
202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
203 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
204 return avail_mem;
205 }
206 }
207
208 sysinfo(&si);
209 avail_mem = (julong)si.freeram * si.mem_unit;
210 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
211 return avail_mem;
212 }
213
214 julong os::physical_memory() {
215 jlong phys_mem = 0;
216 if (OSContainer::is_containerized()) {
217 jlong mem_limit;
218 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
219 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
220 return mem_limit;
221 }
222 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
223 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
224 }
225
226 phys_mem = Linux::physical_memory();
227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
228 return phys_mem;
229 }
230
231 static uint64_t initial_total_ticks = 0;
232 static uint64_t initial_steal_ticks = 0;
233 static bool has_initial_tick_info = false;
234
235 static void next_line(FILE *f) {
236 int c;
237 do {
238 c = fgetc(f);
239 } while (c != '\n' && c != EOF);
240 }
241
242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
243 FILE* fh;
244 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
246 // irq: time servicing interrupts; softirq: time servicing softirqs
247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
249 uint64_t stealTicks = 0;
250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
251 // control of the Linux kernel
252 uint64_t guestNiceTicks = 0;
253 int logical_cpu = -1;
254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
255 int n;
256
257 memset(pticks, 0, sizeof(CPUPerfTicks));
258
259 if ((fh = fopen("/proc/stat", "r")) == NULL) {
260 return false;
261 }
262
263 if (which_logical_cpu == -1) {
264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
266 UINT64_FORMAT " " UINT64_FORMAT " ",
267 &userTicks, &niceTicks, &systemTicks, &idleTicks,
268 &iowTicks, &irqTicks, &sirqTicks,
269 &stealTicks, &guestNiceTicks);
270 } else {
271 // Move to next line
272 next_line(fh);
273
274 // find the line for requested cpu faster to just iterate linefeeds?
275 for (int i = 0; i < which_logical_cpu; i++) {
276 next_line(fh);
277 }
278
279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
281 UINT64_FORMAT " " UINT64_FORMAT " ",
282 &logical_cpu, &userTicks, &niceTicks,
283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
284 &stealTicks, &guestNiceTicks);
285 }
286
287 fclose(fh);
288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
289 return false;
290 }
291 pticks->used = userTicks + niceTicks;
292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
295
296 if (n > required_tickinfo_count + 3) {
297 pticks->steal = stealTicks;
298 pticks->has_steal_ticks = true;
299 } else {
300 pticks->steal = 0;
301 pticks->has_steal_ticks = false;
302 }
303
304 return true;
305 }
306
307 // Return true if user is running as root.
308
309 bool os::have_special_privileges() {
310 static bool init = false;
311 static bool privileges = false;
312 if (!init) {
313 privileges = (getuid() != geteuid()) || (getgid() != getegid());
314 init = true;
315 }
316 return privileges;
317 }
318
319
320 #ifndef SYS_gettid
321 // i386: 224, ia64: 1105, amd64: 186
322 #ifdef __ia64__
323 #define SYS_gettid 1105
324 #else
325 #ifdef __i386__
326 #define SYS_gettid 224
327 #else
328 #ifdef __amd64__
329 #define SYS_gettid 186
330 #else
331 #error define gettid for the arch
332 #endif
333 #endif
334 #endif
335 #endif
336
337
338 // pid_t gettid()
339 //
340 // Returns the kernel thread id of the currently running thread. Kernel
341 // thread id is used to access /proc.
342 pid_t os::Linux::gettid() {
343 int rslt = syscall(SYS_gettid);
344 assert(rslt != -1, "must be."); // old linuxthreads implementation?
345 return (pid_t)rslt;
346 }
347
348 // Most versions of linux have a bug where the number of processors are
349 // determined by looking at the /proc file system. In a chroot environment,
350 // the system call returns 1.
351 static bool unsafe_chroot_detected = false;
352 static const char *unstable_chroot_error = "/proc file system not found.\n"
353 "Java may be unstable running multithreaded in a chroot "
354 "environment on Linux when /proc filesystem is not mounted.";
355
356 void os::Linux::initialize_system_info() {
357 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
358 if (processor_count() == 1) {
359 pid_t pid = os::Linux::gettid();
360 char fname[32];
361 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
362 FILE *fp = fopen(fname, "r");
363 if (fp == NULL) {
364 unsafe_chroot_detected = true;
365 } else {
366 fclose(fp);
367 }
368 }
369 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
370 assert(processor_count() > 0, "linux error");
371 }
372
373 void os::init_system_properties_values() {
374 // The next steps are taken in the product version:
375 //
376 // Obtain the JAVA_HOME value from the location of libjvm.so.
377 // This library should be located at:
378 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
379 //
380 // If "/jre/lib/" appears at the right place in the path, then we
381 // assume libjvm.so is installed in a JDK and we use this path.
382 //
383 // Otherwise exit with message: "Could not create the Java virtual machine."
384 //
385 // The following extra steps are taken in the debugging version:
386 //
387 // If "/jre/lib/" does NOT appear at the right place in the path
388 // instead of exit check for $JAVA_HOME environment variable.
389 //
390 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
391 // then we append a fake suffix "hotspot/libjvm.so" to this path so
392 // it looks like libjvm.so is installed there
393 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
394 //
395 // Otherwise exit.
396 //
397 // Important note: if the location of libjvm.so changes this
398 // code needs to be changed accordingly.
399
400 // See ld(1):
401 // The linker uses the following search paths to locate required
402 // shared libraries:
403 // 1: ...
404 // ...
405 // 7: The default directories, normally /lib and /usr/lib.
406 #ifndef OVERRIDE_LIBPATH
407 #if defined(AMD64) || defined(PPC64) || defined(S390)
408 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
409 #else
410 #define DEFAULT_LIBPATH "/lib:/usr/lib"
411 #endif
412 #else
413 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
414 #endif
415
416 // Base path of extensions installed on the system.
417 #define SYS_EXT_DIR "/usr/java/packages"
418 #define EXTENSIONS_DIR "/lib/ext"
419
420 // Buffer that fits several sprintfs.
421 // Note that the space for the colon and the trailing null are provided
422 // by the nulls included by the sizeof operator.
423 const size_t bufsize =
424 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
425 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
426 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
427
428 // sysclasspath, java_home, dll_dir
429 {
430 char *pslash;
431 os::jvm_path(buf, bufsize);
432
433 // Found the full path to libjvm.so.
434 // Now cut the path to <java_home>/jre if we can.
435 pslash = strrchr(buf, '/');
436 if (pslash != NULL) {
437 *pslash = '\0'; // Get rid of /libjvm.so.
438 }
439 pslash = strrchr(buf, '/');
440 if (pslash != NULL) {
441 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
442 }
443 Arguments::set_dll_dir(buf);
444
445 if (pslash != NULL) {
446 pslash = strrchr(buf, '/');
447 if (pslash != NULL) {
448 *pslash = '\0'; // Get rid of /lib.
449 }
450 }
451 Arguments::set_java_home(buf);
452 if (!set_boot_path('/', ':')) {
453 vm_exit_during_initialization("Failed setting boot class path.", NULL);
454 }
455 }
456
457 // Where to look for native libraries.
458 //
459 // Note: Due to a legacy implementation, most of the library path
460 // is set in the launcher. This was to accomodate linking restrictions
461 // on legacy Linux implementations (which are no longer supported).
462 // Eventually, all the library path setting will be done here.
463 //
464 // However, to prevent the proliferation of improperly built native
465 // libraries, the new path component /usr/java/packages is added here.
466 // Eventually, all the library path setting will be done here.
467 {
468 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
469 // should always exist (until the legacy problem cited above is
470 // addressed).
471 const char *v = ::getenv("LD_LIBRARY_PATH");
472 const char *v_colon = ":";
473 if (v == NULL) { v = ""; v_colon = ""; }
474 // That's +1 for the colon and +1 for the trailing '\0'.
475 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
476 strlen(v) + 1 +
477 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
478 mtInternal);
479 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
480 Arguments::set_library_path(ld_library_path);
481 FREE_C_HEAP_ARRAY(char, ld_library_path);
482 }
483
484 // Extensions directories.
485 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
486 Arguments::set_ext_dirs(buf);
487
488 FREE_C_HEAP_ARRAY(char, buf);
489
490 #undef DEFAULT_LIBPATH
491 #undef SYS_EXT_DIR
492 #undef EXTENSIONS_DIR
493 }
494
495 ////////////////////////////////////////////////////////////////////////////////
496 // breakpoint support
497
498 void os::breakpoint() {
499 BREAKPOINT;
500 }
501
502 extern "C" void breakpoint() {
503 // use debugger to set breakpoint here
504 }
505
506 ////////////////////////////////////////////////////////////////////////////////
507 // signal support
508
509 debug_only(static bool signal_sets_initialized = false);
510 static sigset_t unblocked_sigs, vm_sigs;
511
512 void os::Linux::signal_sets_init() {
513 // Should also have an assertion stating we are still single-threaded.
514 assert(!signal_sets_initialized, "Already initialized");
515 // Fill in signals that are necessarily unblocked for all threads in
516 // the VM. Currently, we unblock the following signals:
517 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
518 // by -Xrs (=ReduceSignalUsage));
519 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
520 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
521 // the dispositions or masks wrt these signals.
522 // Programs embedding the VM that want to use the above signals for their
523 // own purposes must, at this time, use the "-Xrs" option to prevent
524 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
525 // (See bug 4345157, and other related bugs).
526 // In reality, though, unblocking these signals is really a nop, since
527 // these signals are not blocked by default.
528 sigemptyset(&unblocked_sigs);
529 sigaddset(&unblocked_sigs, SIGILL);
530 sigaddset(&unblocked_sigs, SIGSEGV);
531 sigaddset(&unblocked_sigs, SIGBUS);
532 sigaddset(&unblocked_sigs, SIGFPE);
533 #if defined(PPC64)
534 sigaddset(&unblocked_sigs, SIGTRAP);
535 #endif
536 sigaddset(&unblocked_sigs, SR_signum);
537
538 if (!ReduceSignalUsage) {
539 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
540 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
541 }
542 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
543 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
544 }
545 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
546 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
547 }
548 }
549 // Fill in signals that are blocked by all but the VM thread.
550 sigemptyset(&vm_sigs);
551 if (!ReduceSignalUsage) {
552 sigaddset(&vm_sigs, BREAK_SIGNAL);
553 }
554 debug_only(signal_sets_initialized = true);
555
556 }
557
558 // These are signals that are unblocked while a thread is running Java.
559 // (For some reason, they get blocked by default.)
560 sigset_t* os::Linux::unblocked_signals() {
561 assert(signal_sets_initialized, "Not initialized");
562 return &unblocked_sigs;
563 }
564
565 // These are the signals that are blocked while a (non-VM) thread is
566 // running Java. Only the VM thread handles these signals.
567 sigset_t* os::Linux::vm_signals() {
568 assert(signal_sets_initialized, "Not initialized");
569 return &vm_sigs;
570 }
571
572 void os::Linux::hotspot_sigmask(Thread* thread) {
573
574 //Save caller's signal mask before setting VM signal mask
575 sigset_t caller_sigmask;
576 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
577
578 OSThread* osthread = thread->osthread();
579 osthread->set_caller_sigmask(caller_sigmask);
580
581 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
582
583 if (!ReduceSignalUsage) {
584 if (thread->is_VM_thread()) {
585 // Only the VM thread handles BREAK_SIGNAL ...
586 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
587 } else {
588 // ... all other threads block BREAK_SIGNAL
589 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
590 }
591 }
592 }
593
594 //////////////////////////////////////////////////////////////////////////////
595 // detecting pthread library
596
597 void os::Linux::libpthread_init() {
598 // Save glibc and pthread version strings.
599 #if !defined(_CS_GNU_LIBC_VERSION) || \
600 !defined(_CS_GNU_LIBPTHREAD_VERSION)
601 #error "glibc too old (< 2.3.2)"
602 #endif
603
604 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
605 assert(n > 0, "cannot retrieve glibc version");
606 char *str = (char *)malloc(n, mtInternal);
607 confstr(_CS_GNU_LIBC_VERSION, str, n);
608 os::Linux::set_glibc_version(str);
609
610 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
611 assert(n > 0, "cannot retrieve pthread version");
612 str = (char *)malloc(n, mtInternal);
613 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
614 os::Linux::set_libpthread_version(str);
615 }
616
617 /////////////////////////////////////////////////////////////////////////////
618 // thread stack expansion
619
620 // os::Linux::manually_expand_stack() takes care of expanding the thread
621 // stack. Note that this is normally not needed: pthread stacks allocate
622 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
623 // committed. Therefore it is not necessary to expand the stack manually.
624 //
625 // Manually expanding the stack was historically needed on LinuxThreads
626 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
627 // it is kept to deal with very rare corner cases:
628 //
629 // For one, user may run the VM on an own implementation of threads
630 // whose stacks are - like the old LinuxThreads - implemented using
631 // mmap(MAP_GROWSDOWN).
632 //
633 // Also, this coding may be needed if the VM is running on the primordial
634 // thread. Normally we avoid running on the primordial thread; however,
635 // user may still invoke the VM on the primordial thread.
636 //
637 // The following historical comment describes the details about running
638 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
639
640
641 // Force Linux kernel to expand current thread stack. If "bottom" is close
642 // to the stack guard, caller should block all signals.
643 //
644 // MAP_GROWSDOWN:
645 // A special mmap() flag that is used to implement thread stacks. It tells
646 // kernel that the memory region should extend downwards when needed. This
647 // allows early versions of LinuxThreads to only mmap the first few pages
648 // when creating a new thread. Linux kernel will automatically expand thread
649 // stack as needed (on page faults).
650 //
651 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
652 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
653 // region, it's hard to tell if the fault is due to a legitimate stack
654 // access or because of reading/writing non-exist memory (e.g. buffer
655 // overrun). As a rule, if the fault happens below current stack pointer,
656 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
657 // application (see Linux kernel fault.c).
658 //
659 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
660 // stack overflow detection.
661 //
662 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
663 // not use MAP_GROWSDOWN.
664 //
665 // To get around the problem and allow stack banging on Linux, we need to
666 // manually expand thread stack after receiving the SIGSEGV.
667 //
668 // There are two ways to expand thread stack to address "bottom", we used
669 // both of them in JVM before 1.5:
670 // 1. adjust stack pointer first so that it is below "bottom", and then
671 // touch "bottom"
672 // 2. mmap() the page in question
673 //
674 // Now alternate signal stack is gone, it's harder to use 2. For instance,
675 // if current sp is already near the lower end of page 101, and we need to
676 // call mmap() to map page 100, it is possible that part of the mmap() frame
677 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
678 // That will destroy the mmap() frame and cause VM to crash.
679 //
680 // The following code works by adjusting sp first, then accessing the "bottom"
681 // page to force a page fault. Linux kernel will then automatically expand the
682 // stack mapping.
683 //
684 // _expand_stack_to() assumes its frame size is less than page size, which
685 // should always be true if the function is not inlined.
686
687 static void NOINLINE _expand_stack_to(address bottom) {
688 address sp;
689 size_t size;
690 volatile char *p;
691
692 // Adjust bottom to point to the largest address within the same page, it
693 // gives us a one-page buffer if alloca() allocates slightly more memory.
694 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
695 bottom += os::Linux::page_size() - 1;
696
697 // sp might be slightly above current stack pointer; if that's the case, we
698 // will alloca() a little more space than necessary, which is OK. Don't use
699 // os::current_stack_pointer(), as its result can be slightly below current
700 // stack pointer, causing us to not alloca enough to reach "bottom".
701 sp = (address)&sp;
702
703 if (sp > bottom) {
704 size = sp - bottom;
705 p = (volatile char *)alloca(size);
706 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
707 p[0] = '\0';
708 }
709 }
710
711 void os::Linux::expand_stack_to(address bottom) {
712 _expand_stack_to(bottom);
713 }
714
715 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
716 assert(t!=NULL, "just checking");
717 assert(t->osthread()->expanding_stack(), "expand should be set");
718
719 if (t->is_in_usable_stack(addr)) {
720 sigset_t mask_all, old_sigset;
721 sigfillset(&mask_all);
722 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
723 _expand_stack_to(addr);
724 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
725 return true;
726 }
727 return false;
728 }
729
730 //////////////////////////////////////////////////////////////////////////////
731 // create new thread
732
733 // Thread start routine for all newly created threads
734 static void *thread_native_entry(Thread *thread) {
735
736 thread->record_stack_base_and_size();
737
738 // Try to randomize the cache line index of hot stack frames.
739 // This helps when threads of the same stack traces evict each other's
740 // cache lines. The threads can be either from the same JVM instance, or
741 // from different JVM instances. The benefit is especially true for
742 // processors with hyperthreading technology.
743 static int counter = 0;
744 int pid = os::current_process_id();
745 alloca(((pid ^ counter++) & 7) * 128);
746
747 thread->initialize_thread_current();
748
749 OSThread* osthread = thread->osthread();
750 Monitor* sync = osthread->startThread_lock();
751
752 osthread->set_thread_id(os::current_thread_id());
753
754 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
755 os::current_thread_id(), (uintx) pthread_self());
756
757 if (UseNUMA) {
758 int lgrp_id = os::numa_get_group_id();
759 if (lgrp_id != -1) {
760 thread->set_lgrp_id(lgrp_id);
761 }
762 }
763 // initialize signal mask for this thread
764 os::Linux::hotspot_sigmask(thread);
765
766 // initialize floating point control register
767 os::Linux::init_thread_fpu_state();
768
769 // handshaking with parent thread
770 {
771 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
772
773 // notify parent thread
774 osthread->set_state(INITIALIZED);
775 sync->notify_all();
776
777 // wait until os::start_thread()
778 while (osthread->get_state() == INITIALIZED) {
779 sync->wait_without_safepoint_check();
780 }
781 }
782
783 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
784
785 // call one more level start routine
786 thread->call_run();
787
788 // Note: at this point the thread object may already have deleted itself.
789 // Prevent dereferencing it from here on out.
790 thread = NULL;
791
792 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
793 os::current_thread_id(), (uintx) pthread_self());
794
795 return 0;
796 }
797
798 // On Linux, glibc places static TLS blocks (for __thread variables) on
799 // the thread stack. This decreases the stack size actually available
800 // to threads.
801 //
802 // For large static TLS sizes, this may cause threads to malfunction due
803 // to insufficient stack space. This is a well-known issue in glibc:
804 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
805 //
806 // As a workaround, we call a private but assumed-stable glibc function,
807 // __pthread_get_minstack() to obtain the minstack size and derive the
808 // static TLS size from it. We then increase the user requested stack
809 // size by this TLS size.
810 //
811 // Due to compatibility concerns, this size adjustment is opt-in and
812 // controlled via AdjustStackSizeForTLS.
813 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
814
815 GetMinStack _get_minstack_func = NULL;
816
817 static void get_minstack_init() {
818 _get_minstack_func =
819 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
820 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
821 _get_minstack_func == NULL ? "failed" : "succeeded");
822 }
823
824 // Returns the size of the static TLS area glibc puts on thread stacks.
825 // The value is cached on first use, which occurs when the first thread
826 // is created during VM initialization.
827 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
828 size_t tls_size = 0;
829 if (_get_minstack_func != NULL) {
830 // Obtain the pthread minstack size by calling __pthread_get_minstack.
831 size_t minstack_size = _get_minstack_func(attr);
832
833 // Remove non-TLS area size included in minstack size returned
834 // by __pthread_get_minstack() to get the static TLS size.
835 // In glibc before 2.27, minstack size includes guard_size.
836 // In glibc 2.27 and later, guard_size is automatically added
837 // to the stack size by pthread_create and is no longer included
838 // in minstack size. In both cases, the guard_size is taken into
839 // account, so there is no need to adjust the result for that.
840 //
841 // Although __pthread_get_minstack() is a private glibc function,
842 // it is expected to have a stable behavior across future glibc
843 // versions while glibc still allocates the static TLS blocks off
844 // the stack. Following is glibc 2.28 __pthread_get_minstack():
845 //
846 // size_t
847 // __pthread_get_minstack (const pthread_attr_t *attr)
848 // {
849 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
850 // }
851 //
852 //
853 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
854 // if check is done for precaution.
855 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
856 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
857 }
858 }
859
860 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
861 tls_size);
862 return tls_size;
863 }
864
865 bool os::create_thread(Thread* thread, ThreadType thr_type,
866 size_t req_stack_size) {
867 assert(thread->osthread() == NULL, "caller responsible");
868
869 // Allocate the OSThread object
870 OSThread* osthread = new OSThread(NULL, NULL);
871 if (osthread == NULL) {
872 return false;
873 }
874
875 // set the correct thread state
876 osthread->set_thread_type(thr_type);
877
878 // Initial state is ALLOCATED but not INITIALIZED
879 osthread->set_state(ALLOCATED);
880
881 thread->set_osthread(osthread);
882
883 // init thread attributes
884 pthread_attr_t attr;
885 pthread_attr_init(&attr);
886 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
887
888 // Calculate stack size if it's not specified by caller.
889 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
890 // In glibc versions prior to 2.7 the guard size mechanism
891 // is not implemented properly. The posix standard requires adding
892 // the size of the guard pages to the stack size, instead Linux
893 // takes the space out of 'stacksize'. Thus we adapt the requested
894 // stack_size by the size of the guard pages to mimick proper
895 // behaviour. However, be careful not to end up with a size
896 // of zero due to overflow. Don't add the guard page in that case.
897 size_t guard_size = os::Linux::default_guard_size(thr_type);
898 // Configure glibc guard page. Must happen before calling
899 // get_static_tls_area_size(), which uses the guard_size.
900 pthread_attr_setguardsize(&attr, guard_size);
901
902 size_t stack_adjust_size = 0;
903 if (AdjustStackSizeForTLS) {
904 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
905 stack_adjust_size += get_static_tls_area_size(&attr);
906 } else {
907 stack_adjust_size += guard_size;
908 }
909
910 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
911 if (stack_size <= SIZE_MAX - stack_adjust_size) {
912 stack_size += stack_adjust_size;
913 }
914 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
915
916 int status = pthread_attr_setstacksize(&attr, stack_size);
917 assert_status(status == 0, status, "pthread_attr_setstacksize");
918
919 ThreadState state;
920
921 {
922 pthread_t tid;
923 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
924
925 char buf[64];
926 if (ret == 0) {
927 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
928 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
929 } else {
930 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
931 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
932 // Log some OS information which might explain why creating the thread failed.
933 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
934 LogStream st(Log(os, thread)::info());
935 os::Posix::print_rlimit_info(&st);
936 os::print_memory_info(&st);
937 os::Linux::print_proc_sys_info(&st);
938 os::Linux::print_container_info(&st);
939 }
940
941 pthread_attr_destroy(&attr);
942
943 if (ret != 0) {
944 // Need to clean up stuff we've allocated so far
945 thread->set_osthread(NULL);
946 delete osthread;
947 return false;
948 }
949
950 // Store pthread info into the OSThread
951 osthread->set_pthread_id(tid);
952
953 // Wait until child thread is either initialized or aborted
954 {
955 Monitor* sync_with_child = osthread->startThread_lock();
956 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
957 while ((state = osthread->get_state()) == ALLOCATED) {
958 sync_with_child->wait_without_safepoint_check();
959 }
960 }
961 }
962
963 // Aborted due to thread limit being reached
964 if (state == ZOMBIE) {
965 thread->set_osthread(NULL);
966 delete osthread;
967 return false;
968 }
969
970 // The thread is returned suspended (in state INITIALIZED),
971 // and is started higher up in the call chain
972 assert(state == INITIALIZED, "race condition");
973 return true;
974 }
975
976 /////////////////////////////////////////////////////////////////////////////
977 // attach existing thread
978
979 // bootstrap the main thread
980 bool os::create_main_thread(JavaThread* thread) {
981 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
982 return create_attached_thread(thread);
983 }
984
985 bool os::create_attached_thread(JavaThread* thread) {
986 #ifdef ASSERT
987 thread->verify_not_published();
988 #endif
989
990 // Allocate the OSThread object
991 OSThread* osthread = new OSThread(NULL, NULL);
992
993 if (osthread == NULL) {
994 return false;
995 }
996
997 // Store pthread info into the OSThread
998 osthread->set_thread_id(os::Linux::gettid());
999 osthread->set_pthread_id(::pthread_self());
1000
1001 // initialize floating point control register
1002 os::Linux::init_thread_fpu_state();
1003
1004 // Initial thread state is RUNNABLE
1005 osthread->set_state(RUNNABLE);
1006
1007 thread->set_osthread(osthread);
1008
1009 if (UseNUMA) {
1010 int lgrp_id = os::numa_get_group_id();
1011 if (lgrp_id != -1) {
1012 thread->set_lgrp_id(lgrp_id);
1013 }
1014 }
1015
1016 if (os::is_primordial_thread()) {
1017 // If current thread is primordial thread, its stack is mapped on demand,
1018 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1019 // the entire stack region to avoid SEGV in stack banging.
1020 // It is also useful to get around the heap-stack-gap problem on SuSE
1021 // kernel (see 4821821 for details). We first expand stack to the top
1022 // of yellow zone, then enable stack yellow zone (order is significant,
1023 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1024 // is no gap between the last two virtual memory regions.
1025
1026 JavaThread *jt = (JavaThread *)thread;
1027 address addr = jt->stack_reserved_zone_base();
1028 assert(addr != NULL, "initialization problem?");
1029 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1030
1031 osthread->set_expanding_stack();
1032 os::Linux::manually_expand_stack(jt, addr);
1033 osthread->clear_expanding_stack();
1034 }
1035
1036 // initialize signal mask for this thread
1037 // and save the caller's signal mask
1038 os::Linux::hotspot_sigmask(thread);
1039
1040 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
1041 os::current_thread_id(), (uintx) pthread_self());
1042
1043 return true;
1044 }
1045
1046 void os::pd_start_thread(Thread* thread) {
1047 OSThread * osthread = thread->osthread();
1048 assert(osthread->get_state() != INITIALIZED, "just checking");
1049 Monitor* sync_with_child = osthread->startThread_lock();
1050 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1051 sync_with_child->notify();
1052 }
1053
1054 // Free Linux resources related to the OSThread
1055 void os::free_thread(OSThread* osthread) {
1056 assert(osthread != NULL, "osthread not set");
1057
1058 // We are told to free resources of the argument thread,
1059 // but we can only really operate on the current thread.
1060 assert(Thread::current()->osthread() == osthread,
1061 "os::free_thread but not current thread");
1062
1063 #ifdef ASSERT
1064 sigset_t current;
1065 sigemptyset(¤t);
1066 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1067 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
1068 #endif
1069
1070 // Restore caller's signal mask
1071 sigset_t sigmask = osthread->caller_sigmask();
1072 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1073
1074 delete osthread;
1075 }
1076
1077 //////////////////////////////////////////////////////////////////////////////
1078 // primordial thread
1079
1080 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1081 bool os::is_primordial_thread(void) {
1082 if (suppress_primordial_thread_resolution) {
1083 return false;
1084 }
1085 char dummy;
1086 // If called before init complete, thread stack bottom will be null.
1087 // Can be called if fatal error occurs before initialization.
1088 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1089 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1090 os::Linux::initial_thread_stack_size() != 0,
1091 "os::init did not locate primordial thread's stack region");
1092 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1093 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1094 os::Linux::initial_thread_stack_size()) {
1095 return true;
1096 } else {
1097 return false;
1098 }
1099 }
1100
1101 // Find the virtual memory area that contains addr
1102 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1103 FILE *fp = fopen("/proc/self/maps", "r");
1104 if (fp) {
1105 address low, high;
1106 while (!feof(fp)) {
1107 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1108 if (low <= addr && addr < high) {
1109 if (vma_low) *vma_low = low;
1110 if (vma_high) *vma_high = high;
1111 fclose(fp);
1112 return true;
1113 }
1114 }
1115 for (;;) {
1116 int ch = fgetc(fp);
1117 if (ch == EOF || ch == (int)'\n') break;
1118 }
1119 }
1120 fclose(fp);
1121 }
1122 return false;
1123 }
1124
1125 // Locate primordial thread stack. This special handling of primordial thread stack
1126 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1127 // bogus value for the primordial process thread. While the launcher has created
1128 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1129 // JNI invocation API from a primordial thread.
1130 void os::Linux::capture_initial_stack(size_t max_size) {
1131
1132 // max_size is either 0 (which means accept OS default for thread stacks) or
1133 // a user-specified value known to be at least the minimum needed. If we
1134 // are actually on the primordial thread we can make it appear that we have a
1135 // smaller max_size stack by inserting the guard pages at that location. But we
1136 // cannot do anything to emulate a larger stack than what has been provided by
1137 // the OS or threading library. In fact if we try to use a stack greater than
1138 // what is set by rlimit then we will crash the hosting process.
1139
1140 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1141 // If this is "unlimited" then it will be a huge value.
1142 struct rlimit rlim;
1143 getrlimit(RLIMIT_STACK, &rlim);
1144 size_t stack_size = rlim.rlim_cur;
1145
1146 // 6308388: a bug in ld.so will relocate its own .data section to the
1147 // lower end of primordial stack; reduce ulimit -s value a little bit
1148 // so we won't install guard page on ld.so's data section.
1149 // But ensure we don't underflow the stack size - allow 1 page spare
1150 if (stack_size >= (size_t)(3 * page_size())) {
1151 stack_size -= 2 * page_size();
1152 }
1153
1154 // Try to figure out where the stack base (top) is. This is harder.
1155 //
1156 // When an application is started, glibc saves the initial stack pointer in
1157 // a global variable "__libc_stack_end", which is then used by system
1158 // libraries. __libc_stack_end should be pretty close to stack top. The
1159 // variable is available since the very early days. However, because it is
1160 // a private interface, it could disappear in the future.
1161 //
1162 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1163 // to __libc_stack_end, it is very close to stack top, but isn't the real
1164 // stack top. Note that /proc may not exist if VM is running as a chroot
1165 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1166 // /proc/<pid>/stat could change in the future (though unlikely).
1167 //
1168 // We try __libc_stack_end first. If that doesn't work, look for
1169 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1170 // as a hint, which should work well in most cases.
1171
1172 uintptr_t stack_start;
1173
1174 // try __libc_stack_end first
1175 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1176 if (p && *p) {
1177 stack_start = *p;
1178 } else {
1179 // see if we can get the start_stack field from /proc/self/stat
1180 FILE *fp;
1181 int pid;
1182 char state;
1183 int ppid;
1184 int pgrp;
1185 int session;
1186 int nr;
1187 int tpgrp;
1188 unsigned long flags;
1189 unsigned long minflt;
1190 unsigned long cminflt;
1191 unsigned long majflt;
1192 unsigned long cmajflt;
1193 unsigned long utime;
1194 unsigned long stime;
1195 long cutime;
1196 long cstime;
1197 long prio;
1198 long nice;
1199 long junk;
1200 long it_real;
1201 uintptr_t start;
1202 uintptr_t vsize;
1203 intptr_t rss;
1204 uintptr_t rsslim;
1205 uintptr_t scodes;
1206 uintptr_t ecode;
1207 int i;
1208
1209 // Figure what the primordial thread stack base is. Code is inspired
1210 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1211 // followed by command name surrounded by parentheses, state, etc.
1212 char stat[2048];
1213 int statlen;
1214
1215 fp = fopen("/proc/self/stat", "r");
1216 if (fp) {
1217 statlen = fread(stat, 1, 2047, fp);
1218 stat[statlen] = '\0';
1219 fclose(fp);
1220
1221 // Skip pid and the command string. Note that we could be dealing with
1222 // weird command names, e.g. user could decide to rename java launcher
1223 // to "java 1.4.2 :)", then the stat file would look like
1224 // 1234 (java 1.4.2 :)) R ... ...
1225 // We don't really need to know the command string, just find the last
1226 // occurrence of ")" and then start parsing from there. See bug 4726580.
1227 char * s = strrchr(stat, ')');
1228
1229 i = 0;
1230 if (s) {
1231 // Skip blank chars
1232 do { s++; } while (s && isspace(*s));
1233
1234 #define _UFM UINTX_FORMAT
1235 #define _DFM INTX_FORMAT
1236
1237 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1238 // 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
1239 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,
1240 &state, // 3 %c
1241 &ppid, // 4 %d
1242 &pgrp, // 5 %d
1243 &session, // 6 %d
1244 &nr, // 7 %d
1245 &tpgrp, // 8 %d
1246 &flags, // 9 %lu
1247 &minflt, // 10 %lu
1248 &cminflt, // 11 %lu
1249 &majflt, // 12 %lu
1250 &cmajflt, // 13 %lu
1251 &utime, // 14 %lu
1252 &stime, // 15 %lu
1253 &cutime, // 16 %ld
1254 &cstime, // 17 %ld
1255 &prio, // 18 %ld
1256 &nice, // 19 %ld
1257 &junk, // 20 %ld
1258 &it_real, // 21 %ld
1259 &start, // 22 UINTX_FORMAT
1260 &vsize, // 23 UINTX_FORMAT
1261 &rss, // 24 INTX_FORMAT
1262 &rsslim, // 25 UINTX_FORMAT
1263 &scodes, // 26 UINTX_FORMAT
1264 &ecode, // 27 UINTX_FORMAT
1265 &stack_start); // 28 UINTX_FORMAT
1266 }
1267
1268 #undef _UFM
1269 #undef _DFM
1270
1271 if (i != 28 - 2) {
1272 assert(false, "Bad conversion from /proc/self/stat");
1273 // product mode - assume we are the primordial thread, good luck in the
1274 // embedded case.
1275 warning("Can't detect primordial thread stack location - bad conversion");
1276 stack_start = (uintptr_t) &rlim;
1277 }
1278 } else {
1279 // For some reason we can't open /proc/self/stat (for example, running on
1280 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1281 // most cases, so don't abort:
1282 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1283 stack_start = (uintptr_t) &rlim;
1284 }
1285 }
1286
1287 // Now we have a pointer (stack_start) very close to the stack top, the
1288 // next thing to do is to figure out the exact location of stack top. We
1289 // can find out the virtual memory area that contains stack_start by
1290 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1291 // and its upper limit is the real stack top. (again, this would fail if
1292 // running inside chroot, because /proc may not exist.)
1293
1294 uintptr_t stack_top;
1295 address low, high;
1296 if (find_vma((address)stack_start, &low, &high)) {
1297 // success, "high" is the true stack top. (ignore "low", because initial
1298 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1299 stack_top = (uintptr_t)high;
1300 } else {
1301 // failed, likely because /proc/self/maps does not exist
1302 warning("Can't detect primordial thread stack location - find_vma failed");
1303 // best effort: stack_start is normally within a few pages below the real
1304 // stack top, use it as stack top, and reduce stack size so we won't put
1305 // guard page outside stack.
1306 stack_top = stack_start;
1307 stack_size -= 16 * page_size();
1308 }
1309
1310 // stack_top could be partially down the page so align it
1311 stack_top = align_up(stack_top, page_size());
1312
1313 // Allowed stack value is minimum of max_size and what we derived from rlimit
1314 if (max_size > 0) {
1315 _initial_thread_stack_size = MIN2(max_size, stack_size);
1316 } else {
1317 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1318 // clamp it at 8MB as we do on Solaris
1319 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1320 }
1321 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1322 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1323
1324 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1325
1326 if (log_is_enabled(Info, os, thread)) {
1327 // See if we seem to be on primordial process thread
1328 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1329 uintptr_t(&rlim) < stack_top;
1330
1331 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1332 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1333 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1334 stack_top, intptr_t(_initial_thread_stack_bottom));
1335 }
1336 }
1337
1338 ////////////////////////////////////////////////////////////////////////////////
1339 // time support
1340
1341 #ifndef SUPPORTS_CLOCK_MONOTONIC
1342 #error "Build platform doesn't support clock_gettime and related functionality"
1343 #endif
1344
1345 // Time since start-up in seconds to a fine granularity.
1346 // Used by VMSelfDestructTimer and the MemProfiler.
1347 double os::elapsedTime() {
1348
1349 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1350 }
1351
1352 jlong os::elapsed_counter() {
1353 return javaTimeNanos() - initial_time_count;
1354 }
1355
1356 jlong os::elapsed_frequency() {
1357 return NANOSECS_PER_SEC; // nanosecond resolution
1358 }
1359
1360 bool os::supports_vtime() { return true; }
1361
1362 double os::elapsedVTime() {
1363 struct rusage usage;
1364 int retval = getrusage(RUSAGE_THREAD, &usage);
1365 if (retval == 0) {
1366 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);
1367 } else {
1368 // better than nothing, but not much
1369 return elapsedTime();
1370 }
1371 }
1372
1373 jlong os::javaTimeMillis() {
1374 timeval time;
1375 int status = gettimeofday(&time, NULL);
1376 assert(status != -1, "linux error");
1377 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1378 }
1379
1380 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1381 timeval time;
1382 int status = gettimeofday(&time, NULL);
1383 assert(status != -1, "linux error");
1384 seconds = jlong(time.tv_sec);
1385 nanos = jlong(time.tv_usec) * 1000;
1386 }
1387
1388 void os::Linux::fast_thread_clock_init() {
1389 if (!UseLinuxPosixThreadCPUClocks) {
1390 return;
1391 }
1392 clockid_t clockid;
1393 struct timespec tp;
1394 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1395 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1396
1397 // Switch to using fast clocks for thread cpu time if
1398 // the clock_getres() returns 0 error code.
1399 // Note, that some kernels may support the current thread
1400 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1401 // returned by the pthread_getcpuclockid().
1402 // If the fast Posix clocks are supported then the clock_getres()
1403 // must return at least tp.tv_sec == 0 which means a resolution
1404 // better than 1 sec. This is extra check for reliability.
1405
1406 if (pthread_getcpuclockid_func &&
1407 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1408 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1409 _supports_fast_thread_cpu_time = true;
1410 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1411 }
1412 }
1413
1414 jlong os::javaTimeNanos() {
1415 if (os::supports_monotonic_clock()) {
1416 struct timespec tp;
1417 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1418 assert(status == 0, "gettime error");
1419 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1420 return result;
1421 } else {
1422 timeval time;
1423 int status = gettimeofday(&time, NULL);
1424 assert(status != -1, "linux error");
1425 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1426 return 1000 * usecs;
1427 }
1428 }
1429
1430 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1431 if (os::supports_monotonic_clock()) {
1432 info_ptr->max_value = ALL_64_BITS;
1433
1434 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1435 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1436 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1437 } else {
1438 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1439 info_ptr->max_value = ALL_64_BITS;
1440
1441 // gettimeofday is a real time clock so it skips
1442 info_ptr->may_skip_backward = true;
1443 info_ptr->may_skip_forward = true;
1444 }
1445
1446 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1447 }
1448
1449 // Return the real, user, and system times in seconds from an
1450 // arbitrary fixed point in the past.
1451 bool os::getTimesSecs(double* process_real_time,
1452 double* process_user_time,
1453 double* process_system_time) {
1454 struct tms ticks;
1455 clock_t real_ticks = times(&ticks);
1456
1457 if (real_ticks == (clock_t) (-1)) {
1458 return false;
1459 } else {
1460 double ticks_per_second = (double) clock_tics_per_sec;
1461 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1462 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1463 *process_real_time = ((double) real_ticks) / ticks_per_second;
1464
1465 return true;
1466 }
1467 }
1468
1469
1470 char * os::local_time_string(char *buf, size_t buflen) {
1471 struct tm t;
1472 time_t long_time;
1473 time(&long_time);
1474 localtime_r(&long_time, &t);
1475 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1476 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1477 t.tm_hour, t.tm_min, t.tm_sec);
1478 return buf;
1479 }
1480
1481 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1482 return localtime_r(clock, res);
1483 }
1484
1485 ////////////////////////////////////////////////////////////////////////////////
1486 // runtime exit support
1487
1488 // Note: os::shutdown() might be called very early during initialization, or
1489 // called from signal handler. Before adding something to os::shutdown(), make
1490 // sure it is async-safe and can handle partially initialized VM.
1491 void os::shutdown() {
1492
1493 // allow PerfMemory to attempt cleanup of any persistent resources
1494 perfMemory_exit();
1495
1496 // needs to remove object in file system
1497 AttachListener::abort();
1498
1499 // flush buffered output, finish log files
1500 ostream_abort();
1501
1502 // Check for abort hook
1503 abort_hook_t abort_hook = Arguments::abort_hook();
1504 if (abort_hook != NULL) {
1505 abort_hook();
1506 }
1507
1508 }
1509
1510 // Note: os::abort() might be called very early during initialization, or
1511 // called from signal handler. Before adding something to os::abort(), make
1512 // sure it is async-safe and can handle partially initialized VM.
1513 void os::abort(bool dump_core, void* siginfo, const void* context) {
1514 os::shutdown();
1515 if (dump_core) {
1516 if (DumpPrivateMappingsInCore) {
1517 ClassLoader::close_jrt_image();
1518 }
1519 #ifndef PRODUCT
1520 fdStream out(defaultStream::output_fd());
1521 out.print_raw("Current thread is ");
1522 char buf[16];
1523 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1524 out.print_raw_cr(buf);
1525 out.print_raw_cr("Dumping core ...");
1526 #endif
1527 ::abort(); // dump core
1528 }
1529
1530 ::exit(1);
1531 }
1532
1533 // Die immediately, no exit hook, no abort hook, no cleanup.
1534 // Dump a core file, if possible, for debugging.
1535 void os::die() {
1536 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1537 // For TimeoutInErrorHandlingTest.java, we just kill the VM
1538 // and don't take the time to generate a core file.
1539 os::signal_raise(SIGKILL);
1540 } else {
1541 ::abort();
1542 }
1543 }
1544
1545 // thread_id is kernel thread id (similar to Solaris LWP id)
1546 intx os::current_thread_id() { return os::Linux::gettid(); }
1547 int os::current_process_id() {
1548 return ::getpid();
1549 }
1550
1551 // DLL functions
1552
1553 const char* os::dll_file_extension() { return ".so"; }
1554
1555 // This must be hard coded because it's the system's temporary
1556 // directory not the java application's temp directory, ala java.io.tmpdir.
1557 const char* os::get_temp_directory() { return "/tmp"; }
1558
1559 static bool file_exists(const char* filename) {
1560 struct stat statbuf;
1561 if (filename == NULL || strlen(filename) == 0) {
1562 return false;
1563 }
1564 return os::stat(filename, &statbuf) == 0;
1565 }
1566
1567 // check if addr is inside libjvm.so
1568 bool os::address_is_in_vm(address addr) {
1569 static address libjvm_base_addr;
1570 Dl_info dlinfo;
1571
1572 if (libjvm_base_addr == NULL) {
1573 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1574 libjvm_base_addr = (address)dlinfo.dli_fbase;
1575 }
1576 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1577 }
1578
1579 if (dladdr((void *)addr, &dlinfo) != 0) {
1580 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1581 }
1582
1583 return false;
1584 }
1585
1586 bool os::dll_address_to_function_name(address addr, char *buf,
1587 int buflen, int *offset,
1588 bool demangle) {
1589 // buf is not optional, but offset is optional
1590 assert(buf != NULL, "sanity check");
1591
1592 Dl_info dlinfo;
1593
1594 if (dladdr((void*)addr, &dlinfo) != 0) {
1595 // see if we have a matching symbol
1596 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1597 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1598 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1599 }
1600 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1601 return true;
1602 }
1603 // no matching symbol so try for just file info
1604 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1605 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1606 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1607 return true;
1608 }
1609 }
1610 }
1611
1612 buf[0] = '\0';
1613 if (offset != NULL) *offset = -1;
1614 return false;
1615 }
1616
1617 struct _address_to_library_name {
1618 address addr; // input : memory address
1619 size_t buflen; // size of fname
1620 char* fname; // output: library name
1621 address base; // library base addr
1622 };
1623
1624 static int address_to_library_name_callback(struct dl_phdr_info *info,
1625 size_t size, void *data) {
1626 int i;
1627 bool found = false;
1628 address libbase = NULL;
1629 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1630
1631 // iterate through all loadable segments
1632 for (i = 0; i < info->dlpi_phnum; i++) {
1633 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1634 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1635 // base address of a library is the lowest address of its loaded
1636 // segments.
1637 if (libbase == NULL || libbase > segbase) {
1638 libbase = segbase;
1639 }
1640 // see if 'addr' is within current segment
1641 if (segbase <= d->addr &&
1642 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1643 found = true;
1644 }
1645 }
1646 }
1647
1648 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1649 // so dll_address_to_library_name() can fall through to use dladdr() which
1650 // can figure out executable name from argv[0].
1651 if (found && info->dlpi_name && info->dlpi_name[0]) {
1652 d->base = libbase;
1653 if (d->fname) {
1654 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1655 }
1656 return 1;
1657 }
1658 return 0;
1659 }
1660
1661 bool os::dll_address_to_library_name(address addr, char* buf,
1662 int buflen, int* offset) {
1663 // buf is not optional, but offset is optional
1664 assert(buf != NULL, "sanity check");
1665
1666 Dl_info dlinfo;
1667 struct _address_to_library_name data;
1668
1669 // There is a bug in old glibc dladdr() implementation that it could resolve
1670 // to wrong library name if the .so file has a base address != NULL. Here
1671 // we iterate through the program headers of all loaded libraries to find
1672 // out which library 'addr' really belongs to. This workaround can be
1673 // removed once the minimum requirement for glibc is moved to 2.3.x.
1674 data.addr = addr;
1675 data.fname = buf;
1676 data.buflen = buflen;
1677 data.base = NULL;
1678 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1679
1680 if (rslt) {
1681 // buf already contains library name
1682 if (offset) *offset = addr - data.base;
1683 return true;
1684 }
1685 if (dladdr((void*)addr, &dlinfo) != 0) {
1686 if (dlinfo.dli_fname != NULL) {
1687 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1688 }
1689 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1690 *offset = addr - (address)dlinfo.dli_fbase;
1691 }
1692 return true;
1693 }
1694
1695 buf[0] = '\0';
1696 if (offset) *offset = -1;
1697 return false;
1698 }
1699
1700 // Loads .dll/.so and
1701 // in case of error it checks if .dll/.so was built for the
1702 // same architecture as Hotspot is running on
1703
1704
1705 // Remember the stack's state. The Linux dynamic linker will change
1706 // the stack to 'executable' at most once, so we must safepoint only once.
1707 bool os::Linux::_stack_is_executable = false;
1708
1709 // VM operation that loads a library. This is necessary if stack protection
1710 // of the Java stacks can be lost during loading the library. If we
1711 // do not stop the Java threads, they can stack overflow before the stacks
1712 // are protected again.
1713 class VM_LinuxDllLoad: public VM_Operation {
1714 private:
1715 const char *_filename;
1716 char *_ebuf;
1717 int _ebuflen;
1718 void *_lib;
1719 public:
1720 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1721 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1722 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1723 void doit() {
1724 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1725 os::Linux::_stack_is_executable = true;
1726 }
1727 void* loaded_library() { return _lib; }
1728 };
1729
1730 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1731 void * result = NULL;
1732 bool load_attempted = false;
1733
1734 log_info(os)("attempting shared library load of %s", filename);
1735
1736 // Check whether the library to load might change execution rights
1737 // of the stack. If they are changed, the protection of the stack
1738 // guard pages will be lost. We need a safepoint to fix this.
1739 //
1740 // See Linux man page execstack(8) for more info.
1741 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1742 if (!ElfFile::specifies_noexecstack(filename)) {
1743 if (!is_init_completed()) {
1744 os::Linux::_stack_is_executable = true;
1745 // This is OK - No Java threads have been created yet, and hence no
1746 // stack guard pages to fix.
1747 //
1748 // Dynamic loader will make all stacks executable after
1749 // this function returns, and will not do that again.
1750 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1751 } else {
1752 warning("You have loaded library %s which might have disabled stack guard. "
1753 "The VM will try to fix the stack guard now.\n"
1754 "It's highly recommended that you fix the library with "
1755 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1756 filename);
1757
1758 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1759 JavaThread *jt = JavaThread::current();
1760 if (jt->thread_state() != _thread_in_native) {
1761 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1762 // that requires ExecStack. Cannot enter safe point. Let's give up.
1763 warning("Unable to fix stack guard. Giving up.");
1764 } else {
1765 if (!LoadExecStackDllInVMThread) {
1766 // This is for the case where the DLL has an static
1767 // constructor function that executes JNI code. We cannot
1768 // load such DLLs in the VMThread.
1769 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1770 }
1771
1772 ThreadInVMfromNative tiv(jt);
1773 debug_only(VMNativeEntryWrapper vew;)
1774
1775 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1776 VMThread::execute(&op);
1777 if (LoadExecStackDllInVMThread) {
1778 result = op.loaded_library();
1779 }
1780 load_attempted = true;
1781 }
1782 }
1783 }
1784 }
1785
1786 if (!load_attempted) {
1787 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1788 }
1789
1790 if (result != NULL) {
1791 // Successful loading
1792 return result;
1793 }
1794
1795 Elf32_Ehdr elf_head;
1796 int diag_msg_max_length=ebuflen-strlen(ebuf);
1797 char* diag_msg_buf=ebuf+strlen(ebuf);
1798
1799 if (diag_msg_max_length==0) {
1800 // No more space in ebuf for additional diagnostics message
1801 return NULL;
1802 }
1803
1804
1805 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1806
1807 if (file_descriptor < 0) {
1808 // Can't open library, report dlerror() message
1809 return NULL;
1810 }
1811
1812 bool failed_to_read_elf_head=
1813 (sizeof(elf_head)!=
1814 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1815
1816 ::close(file_descriptor);
1817 if (failed_to_read_elf_head) {
1818 // file i/o error - report dlerror() msg
1819 return NULL;
1820 }
1821
1822 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1823 // handle invalid/out of range endianness values
1824 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1825 return NULL;
1826 }
1827
1828 #if defined(VM_LITTLE_ENDIAN)
1829 // VM is LE, shared object BE
1830 elf_head.e_machine = be16toh(elf_head.e_machine);
1831 #else
1832 // VM is BE, shared object LE
1833 elf_head.e_machine = le16toh(elf_head.e_machine);
1834 #endif
1835 }
1836
1837 typedef struct {
1838 Elf32_Half code; // Actual value as defined in elf.h
1839 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1840 unsigned char elf_class; // 32 or 64 bit
1841 unsigned char endianness; // MSB or LSB
1842 char* name; // String representation
1843 } arch_t;
1844
1845 #ifndef EM_AARCH64
1846 #define EM_AARCH64 183 /* ARM AARCH64 */
1847 #endif
1848 #ifndef EM_RISCV
1849 #define EM_RISCV 243 /* RISC-V */
1850 #endif
1851
1852 static const arch_t arch_array[]={
1853 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1854 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1855 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1856 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1857 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1858 #if defined(VM_LITTLE_ENDIAN)
1859 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1860 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1861 #else
1862 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1863 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1864 #endif
1865 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1866 // we only support 64 bit z architecture
1867 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
1868 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1869 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1870 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1871 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1872 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1873 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1874 {EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISC-V"},
1875 };
1876
1877 #if (defined IA32)
1878 static Elf32_Half running_arch_code=EM_386;
1879 #elif (defined AMD64) || (defined X32)
1880 static Elf32_Half running_arch_code=EM_X86_64;
1881 #elif (defined IA64)
1882 static Elf32_Half running_arch_code=EM_IA_64;
1883 #elif (defined __powerpc64__)
1884 static Elf32_Half running_arch_code=EM_PPC64;
1885 #elif (defined __powerpc__)
1886 static Elf32_Half running_arch_code=EM_PPC;
1887 #elif (defined AARCH64)
1888 static Elf32_Half running_arch_code=EM_AARCH64;
1889 #elif (defined ARM)
1890 static Elf32_Half running_arch_code=EM_ARM;
1891 #elif (defined S390)
1892 static Elf32_Half running_arch_code=EM_S390;
1893 #elif (defined ALPHA)
1894 static Elf32_Half running_arch_code=EM_ALPHA;
1895 #elif (defined MIPSEL)
1896 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1897 #elif (defined PARISC)
1898 static Elf32_Half running_arch_code=EM_PARISC;
1899 #elif (defined MIPS)
1900 static Elf32_Half running_arch_code=EM_MIPS;
1901 #elif (defined M68K)
1902 static Elf32_Half running_arch_code=EM_68K;
1903 #elif (defined SH)
1904 static Elf32_Half running_arch_code=EM_SH;
1905 #elif (defined RISCV)
1906 static Elf32_Half running_arch_code=EM_RISCV;
1907 #else
1908 #error Method os::dll_load requires that one of following is defined:\
1909 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH
1910 #endif
1911
1912 // Identify compatibility class for VM's architecture and library's architecture
1913 // Obtain string descriptions for architectures
1914
1915 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1916 int running_arch_index=-1;
1917
1918 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1919 if (running_arch_code == arch_array[i].code) {
1920 running_arch_index = i;
1921 }
1922 if (lib_arch.code == arch_array[i].code) {
1923 lib_arch.compat_class = arch_array[i].compat_class;
1924 lib_arch.name = arch_array[i].name;
1925 }
1926 }
1927
1928 assert(running_arch_index != -1,
1929 "Didn't find running architecture code (running_arch_code) in arch_array");
1930 if (running_arch_index == -1) {
1931 // Even though running architecture detection failed
1932 // we may still continue with reporting dlerror() message
1933 return NULL;
1934 }
1935
1936 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1937 if (lib_arch.name != NULL) {
1938 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1939 " (Possible cause: can't load %s .so on a %s platform)",
1940 lib_arch.name, arch_array[running_arch_index].name);
1941 } else {
1942 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1943 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1944 lib_arch.code, arch_array[running_arch_index].name);
1945 }
1946 return NULL;
1947 }
1948
1949 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1950 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1951 return NULL;
1952 }
1953
1954 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1955 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1956 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1957 return NULL;
1958 }
1959
1960 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1961 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1962 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1963 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1964 return NULL;
1965 }
1966
1967 return NULL;
1968 }
1969
1970 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1971 int ebuflen) {
1972 void * result = ::dlopen(filename, RTLD_LAZY);
1973 if (result == NULL) {
1974 const char* error_report = ::dlerror();
1975 if (error_report == NULL) {
1976 error_report = "dlerror returned no error description";
1977 }
1978 if (ebuf != NULL && ebuflen > 0) {
1979 ::strncpy(ebuf, error_report, ebuflen-1);
1980 ebuf[ebuflen-1]='\0';
1981 }
1982 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1983 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1984 } else {
1985 Events::log(NULL, "Loaded shared library %s", filename);
1986 log_info(os)("shared library load of %s was successful", filename);
1987 }
1988 return result;
1989 }
1990
1991 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1992 int ebuflen) {
1993 void * result = NULL;
1994 if (LoadExecStackDllInVMThread) {
1995 result = dlopen_helper(filename, ebuf, ebuflen);
1996 }
1997
1998 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1999 // library that requires an executable stack, or which does not have this
2000 // stack attribute set, dlopen changes the stack attribute to executable. The
2001 // read protection of the guard pages gets lost.
2002 //
2003 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2004 // may have been queued at the same time.
2005
2006 if (!_stack_is_executable) {
2007 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2008 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2009 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
2010 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
2011 warning("Attempt to reguard stack yellow zone failed.");
2012 }
2013 }
2014 }
2015 }
2016
2017 return result;
2018 }
2019
2020 void* os::dll_lookup(void* handle, const char* name) {
2021 void* res = dlsym(handle, name);
2022 return res;
2023 }
2024
2025 void* os::get_default_process_handle() {
2026 return (void*)::dlopen(NULL, RTLD_LAZY);
2027 }
2028
2029 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
2030 int fd = ::open(filename, O_RDONLY);
2031 if (fd == -1) {
2032 return false;
2033 }
2034
2035 if (hdr != NULL) {
2036 st->print_cr("%s", hdr);
2037 }
2038
2039 char buf[33];
2040 int bytes;
2041 buf[32] = '\0';
2042 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
2043 st->print_raw(buf, bytes);
2044 }
2045
2046 ::close(fd);
2047
2048 return true;
2049 }
2050
2051 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st) {
2052 st->print("%s", header);
2053 if (!_print_ascii_file(filename, st)) {
2054 st->print_cr("<Not Available>");
2055 }
2056 }
2057
2058 void os::print_dll_info(outputStream *st) {
2059 st->print_cr("Dynamic libraries:");
2060
2061 char fname[32];
2062 pid_t pid = os::Linux::gettid();
2063
2064 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2065
2066 if (!_print_ascii_file(fname, st)) {
2067 st->print("Can not get library information for pid = %d\n", pid);
2068 }
2069 }
2070
2071 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2072 FILE *procmapsFile = NULL;
2073
2074 // Open the procfs maps file for the current process
2075 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2076 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2077 char line[PATH_MAX + 100];
2078
2079 // Read line by line from 'file'
2080 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2081 u8 base, top, inode;
2082 char name[sizeof(line)];
2083
2084 // Parse fields from line, discard perms, offset and device
2085 int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %*s %*s %*s " INT64_FORMAT " %s",
2086 &base, &top, &inode, name);
2087 // the last entry 'name' is empty for some entries, so we might have 3 matches instead of 4 for some lines
2088 if (matches < 3) continue;
2089 if (matches == 3) name[0] = '\0';
2090
2091 // Filter by inode 0 so that we only get file system mapped files.
2092 if (inode != 0) {
2093
2094 // Call callback with the fields of interest
2095 if(callback(name, (address)base, (address)top, param)) {
2096 // Oops abort, callback aborted
2097 fclose(procmapsFile);
2098 return 1;
2099 }
2100 }
2101 }
2102 fclose(procmapsFile);
2103 }
2104 return 0;
2105 }
2106
2107 void os::print_os_info_brief(outputStream* st) {
2108 os::Linux::print_distro_info(st);
2109
2110 os::Posix::print_uname_info(st);
2111
2112 os::Linux::print_libversion_info(st);
2113
2114 }
2115
2116 void os::print_os_info(outputStream* st) {
2117 st->print("OS:");
2118
2119 os::Linux::print_distro_info(st);
2120
2121 os::Posix::print_uname_info(st);
2122
2123 os::Linux::print_uptime_info(st);
2124
2125 // Print warning if unsafe chroot environment detected
2126 if (unsafe_chroot_detected) {
2127 st->print("WARNING!! ");
2128 st->print_cr("%s", unstable_chroot_error);
2129 }
2130
2131 os::Linux::print_libversion_info(st);
2132
2133 os::Posix::print_rlimit_info(st);
2134
2135 os::Posix::print_load_average(st);
2136
2137 os::Linux::print_full_memory_info(st);
2138
2139 os::Linux::print_proc_sys_info(st);
2140
2141 os::Linux::print_ld_preload_file(st);
2142
2143 os::Linux::print_container_info(st);
2144
2145 VM_Version::print_platform_virtualization_info(st);
2146
2147 os::Linux::print_steal_info(st);
2148 }
2149
2150 // Try to identify popular distros.
2151 // Most Linux distributions have a /etc/XXX-release file, which contains
2152 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2153 // file that also contains the OS version string. Some have more than one
2154 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2155 // /etc/redhat-release.), so the order is important.
2156 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2157 // their own specific XXX-release file as well as a redhat-release file.
2158 // Because of this the XXX-release file needs to be searched for before the
2159 // redhat-release file.
2160 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2161 // search for redhat-release / SuSE-release needs to be before lsb-release.
2162 // Since the lsb-release file is the new standard it needs to be searched
2163 // before the older style release files.
2164 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2165 // next to last resort. The os-release file is a new standard that contains
2166 // distribution information and the system-release file seems to be an old
2167 // standard that has been replaced by the lsb-release and os-release files.
2168 // Searching for the debian_version file is the last resort. It contains
2169 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2170 // "Debian " is printed before the contents of the debian_version file.
2171
2172 const char* distro_files[] = {
2173 "/etc/oracle-release",
2174 "/etc/mandriva-release",
2175 "/etc/mandrake-release",
2176 "/etc/sun-release",
2177 "/etc/redhat-release",
2178 "/etc/SuSE-release",
2179 "/etc/lsb-release",
2180 "/etc/turbolinux-release",
2181 "/etc/gentoo-release",
2182 "/etc/ltib-release",
2183 "/etc/angstrom-version",
2184 "/etc/system-release",
2185 "/etc/os-release",
2186 NULL };
2187
2188 void os::Linux::print_distro_info(outputStream* st) {
2189 for (int i = 0;; i++) {
2190 const char* file = distro_files[i];
2191 if (file == NULL) {
2192 break; // done
2193 }
2194 // If file prints, we found it.
2195 if (_print_ascii_file(file, st)) {
2196 return;
2197 }
2198 }
2199
2200 if (file_exists("/etc/debian_version")) {
2201 st->print("Debian ");
2202 _print_ascii_file("/etc/debian_version", st);
2203 } else {
2204 st->print("Linux");
2205 }
2206 st->cr();
2207 }
2208
2209 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2210 char buf[256];
2211 while (fgets(buf, sizeof(buf), fp)) {
2212 // Edit out extra stuff in expected format
2213 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2214 char* ptr = strstr(buf, "\""); // the name is in quotes
2215 if (ptr != NULL) {
2216 ptr++; // go beyond first quote
2217 char* nl = strchr(ptr, '\"');
2218 if (nl != NULL) *nl = '\0';
2219 strncpy(distro, ptr, length);
2220 } else {
2221 ptr = strstr(buf, "=");
2222 ptr++; // go beyond equals then
2223 char* nl = strchr(ptr, '\n');
2224 if (nl != NULL) *nl = '\0';
2225 strncpy(distro, ptr, length);
2226 }
2227 return;
2228 } else if (get_first_line) {
2229 char* nl = strchr(buf, '\n');
2230 if (nl != NULL) *nl = '\0';
2231 strncpy(distro, buf, length);
2232 return;
2233 }
2234 }
2235 // print last line and close
2236 char* nl = strchr(buf, '\n');
2237 if (nl != NULL) *nl = '\0';
2238 strncpy(distro, buf, length);
2239 }
2240
2241 static void parse_os_info(char* distro, size_t length, const char* file) {
2242 FILE* fp = fopen(file, "r");
2243 if (fp != NULL) {
2244 // if suse format, print out first line
2245 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2246 parse_os_info_helper(fp, distro, length, get_first_line);
2247 fclose(fp);
2248 }
2249 }
2250
2251 void os::get_summary_os_info(char* buf, size_t buflen) {
2252 for (int i = 0;; i++) {
2253 const char* file = distro_files[i];
2254 if (file == NULL) {
2255 break; // ran out of distro_files
2256 }
2257 if (file_exists(file)) {
2258 parse_os_info(buf, buflen, file);
2259 return;
2260 }
2261 }
2262 // special case for debian
2263 if (file_exists("/etc/debian_version")) {
2264 strncpy(buf, "Debian ", buflen);
2265 if (buflen > 7) {
2266 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2267 }
2268 } else {
2269 strncpy(buf, "Linux", buflen);
2270 }
2271 }
2272
2273 void os::Linux::print_libversion_info(outputStream* st) {
2274 // libc, pthread
2275 st->print("libc:");
2276 st->print("%s ", os::Linux::glibc_version());
2277 st->print("%s ", os::Linux::libpthread_version());
2278 st->cr();
2279 }
2280
2281 void os::Linux::print_proc_sys_info(outputStream* st) {
2282 st->cr();
2283 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
2284 _print_ascii_file("/proc/sys/kernel/threads-max", st);
2285 st->cr();
2286 st->cr();
2287
2288 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
2289 _print_ascii_file("/proc/sys/vm/max_map_count", st);
2290 st->cr();
2291 st->cr();
2292
2293 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
2294 _print_ascii_file("/proc/sys/kernel/pid_max", st);
2295 st->cr();
2296 st->cr();
2297 }
2298
2299 void os::Linux::print_full_memory_info(outputStream* st) {
2300 st->print("\n/proc/meminfo:\n");
2301 _print_ascii_file("/proc/meminfo", st);
2302 st->cr();
2303
2304 // some information regarding THPs; for details see
2305 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt
2306 st->print_cr("/sys/kernel/mm/transparent_hugepage/enabled:");
2307 if (!_print_ascii_file("/sys/kernel/mm/transparent_hugepage/enabled", st)) {
2308 st->print_cr(" <Not Available>");
2309 }
2310 st->cr();
2311 st->print_cr("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter):");
2312 if (!_print_ascii_file("/sys/kernel/mm/transparent_hugepage/defrag", st)) {
2313 st->print_cr(" <Not Available>");
2314 }
2315 st->cr();
2316 }
2317
2318 void os::Linux::print_ld_preload_file(outputStream* st) {
2319 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2320 st->cr();
2321 }
2322
2323 void os::Linux::print_uptime_info(outputStream* st) {
2324 struct sysinfo sinfo;
2325 int ret = sysinfo(&sinfo);
2326 if (ret == 0) {
2327 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
2328 }
2329 }
2330
2331
2332 void os::Linux::print_container_info(outputStream* st) {
2333 if (!OSContainer::is_containerized()) {
2334 return;
2335 }
2336
2337 st->print("container (cgroup) information:\n");
2338
2339 const char *p_ct = OSContainer::container_type();
2340 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2341
2342 char *p = OSContainer::cpu_cpuset_cpus();
2343 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2344 free(p);
2345
2346 p = OSContainer::cpu_cpuset_memory_nodes();
2347 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2348 free(p);
2349
2350 int i = OSContainer::active_processor_count();
2351 st->print("active_processor_count: ");
2352 if (i > 0) {
2353 st->print("%d\n", i);
2354 } else {
2355 st->print("not supported\n");
2356 }
2357
2358 i = OSContainer::cpu_quota();
2359 st->print("cpu_quota: ");
2360 if (i > 0) {
2361 st->print("%d\n", i);
2362 } else {
2363 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2364 }
2365
2366 i = OSContainer::cpu_period();
2367 st->print("cpu_period: ");
2368 if (i > 0) {
2369 st->print("%d\n", i);
2370 } else {
2371 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2372 }
2373
2374 i = OSContainer::cpu_shares();
2375 st->print("cpu_shares: ");
2376 if (i > 0) {
2377 st->print("%d\n", i);
2378 } else {
2379 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2380 }
2381
2382 jlong j = OSContainer::memory_limit_in_bytes();
2383 st->print("memory_limit_in_bytes: ");
2384 if (j > 0) {
2385 st->print(JLONG_FORMAT "\n", j);
2386 } else {
2387 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2388 }
2389
2390 j = OSContainer::memory_and_swap_limit_in_bytes();
2391 st->print("memory_and_swap_limit_in_bytes: ");
2392 if (j > 0) {
2393 st->print(JLONG_FORMAT "\n", j);
2394 } else {
2395 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2396 }
2397
2398 j = OSContainer::memory_soft_limit_in_bytes();
2399 st->print("memory_soft_limit_in_bytes: ");
2400 if (j > 0) {
2401 st->print(JLONG_FORMAT "\n", j);
2402 } else {
2403 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2404 }
2405
2406 j = OSContainer::OSContainer::memory_usage_in_bytes();
2407 st->print("memory_usage_in_bytes: ");
2408 if (j > 0) {
2409 st->print(JLONG_FORMAT "\n", j);
2410 } else {
2411 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2412 }
2413
2414 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2415 st->print("memory_max_usage_in_bytes: ");
2416 if (j > 0) {
2417 st->print(JLONG_FORMAT "\n", j);
2418 } else {
2419 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2420 }
2421 st->cr();
2422 }
2423
2424 void os::Linux::print_steal_info(outputStream* st) {
2425 if (has_initial_tick_info) {
2426 CPUPerfTicks pticks;
2427 bool res = os::Linux::get_tick_information(&pticks, -1);
2428
2429 if (res && pticks.has_steal_ticks) {
2430 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2431 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2432 double steal_ticks_perc = 0.0;
2433 if (total_ticks_difference != 0) {
2434 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2435 }
2436 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2437 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2438 }
2439 }
2440 }
2441
2442 void os::print_memory_info(outputStream* st) {
2443
2444 st->print("Memory:");
2445 st->print(" %dk page", os::vm_page_size()>>10);
2446
2447 // values in struct sysinfo are "unsigned long"
2448 struct sysinfo si;
2449 sysinfo(&si);
2450
2451 st->print(", physical " UINT64_FORMAT "k",
2452 os::physical_memory() >> 10);
2453 st->print("(" UINT64_FORMAT "k free)",
2454 os::available_memory() >> 10);
2455 st->print(", swap " UINT64_FORMAT "k",
2456 ((jlong)si.totalswap * si.mem_unit) >> 10);
2457 st->print("(" UINT64_FORMAT "k free)",
2458 ((jlong)si.freeswap * si.mem_unit) >> 10);
2459 st->cr();
2460 }
2461
2462 // Print the first "model name" line and the first "flags" line
2463 // that we find and nothing more. We assume "model name" comes
2464 // before "flags" so if we find a second "model name", then the
2465 // "flags" field is considered missing.
2466 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2467 #if defined(IA32) || defined(AMD64)
2468 // Other platforms have less repetitive cpuinfo files
2469 FILE *fp = fopen("/proc/cpuinfo", "r");
2470 if (fp) {
2471 while (!feof(fp)) {
2472 if (fgets(buf, buflen, fp)) {
2473 // Assume model name comes before flags
2474 bool model_name_printed = false;
2475 if (strstr(buf, "model name") != NULL) {
2476 if (!model_name_printed) {
2477 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2478 st->print_raw(buf);
2479 model_name_printed = true;
2480 } else {
2481 // model name printed but not flags? Odd, just return
2482 fclose(fp);
2483 return true;
2484 }
2485 }
2486 // print the flags line too
2487 if (strstr(buf, "flags") != NULL) {
2488 st->print_raw(buf);
2489 fclose(fp);
2490 return true;
2491 }
2492 }
2493 }
2494 fclose(fp);
2495 }
2496 #endif // x86 platforms
2497 return false;
2498 }
2499
2500 // additional information about CPU e.g. available frequency ranges
2501 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) {
2502 _print_ascii_file_h("Online cpus:", "/sys/devices/system/cpu/online", st);
2503 _print_ascii_file_h("Offline cpus:", "/sys/devices/system/cpu/offline", st);
2504
2505 if (ExtensiveErrorReports) {
2506 // cache related info (cpu 0, should be similar for other CPUs)
2507 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries
2508 char hbuf_level[60];
2509 char hbuf_type[60];
2510 char hbuf_size[60];
2511 char hbuf_coherency_line_size[80];
2512 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i);
2513 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i);
2514 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i);
2515 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i);
2516 if (file_exists(hbuf_level)) {
2517 _print_ascii_file_h("cache level:", hbuf_level, st);
2518 _print_ascii_file_h("cache type:", hbuf_type, st);
2519 _print_ascii_file_h("cache size:", hbuf_size, st);
2520 _print_ascii_file_h("cache coherency line size:", hbuf_coherency_line_size, st);
2521 }
2522 }
2523 }
2524
2525 // we miss the cpufreq entries on Power and s390x
2526 #if defined(IA32) || defined(AMD64)
2527 _print_ascii_file_h("BIOS frequency limitation:", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st);
2528 _print_ascii_file_h("Frequency switch latency (ns):", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st);
2529 _print_ascii_file_h("Available cpu frequencies:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st);
2530 // min and max should be in the Available range but still print them (not all info might be available for all kernels)
2531 if (ExtensiveErrorReports) {
2532 _print_ascii_file_h("Maximum cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st);
2533 _print_ascii_file_h("Minimum cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st);
2534 _print_ascii_file_h("Current cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st);
2535 }
2536 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling
2537 if (ExtensiveErrorReports) {
2538 _print_ascii_file_h("Available governors:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st);
2539 }
2540 _print_ascii_file_h("Current governor:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st);
2541 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt
2542 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g.
2543 // whole chip is not fully utilized
2544 _print_ascii_file_h("Core performance/turbo boost:", "/sys/devices/system/cpu/cpufreq/boost", st);
2545 #endif
2546 }
2547
2548 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2549 // Only print the model name if the platform provides this as a summary
2550 if (!print_model_name_and_flags(st, buf, buflen)) {
2551 st->print("\n/proc/cpuinfo:\n");
2552 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2553 st->print_cr(" <Not Available>");
2554 }
2555 }
2556 print_sys_devices_cpu_info(st, buf, buflen);
2557 }
2558
2559 #if defined(AMD64) || defined(IA32) || defined(X32)
2560 const char* search_string = "model name";
2561 #elif defined(M68K)
2562 const char* search_string = "CPU";
2563 #elif defined(PPC64)
2564 const char* search_string = "cpu";
2565 #elif defined(S390)
2566 const char* search_string = "machine =";
2567 #else
2568 const char* search_string = "Processor";
2569 #endif
2570
2571 // Parses the cpuinfo file for string representing the model name.
2572 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2573 FILE* fp = fopen("/proc/cpuinfo", "r");
2574 if (fp != NULL) {
2575 while (!feof(fp)) {
2576 char buf[256];
2577 if (fgets(buf, sizeof(buf), fp)) {
2578 char* start = strstr(buf, search_string);
2579 if (start != NULL) {
2580 char *ptr = start + strlen(search_string);
2581 char *end = buf + strlen(buf);
2582 while (ptr != end) {
2583 // skip whitespace and colon for the rest of the name.
2584 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2585 break;
2586 }
2587 ptr++;
2588 }
2589 if (ptr != end) {
2590 // reasonable string, get rid of newline and keep the rest
2591 char* nl = strchr(buf, '\n');
2592 if (nl != NULL) *nl = '\0';
2593 strncpy(cpuinfo, ptr, length);
2594 fclose(fp);
2595 return;
2596 }
2597 }
2598 }
2599 }
2600 fclose(fp);
2601 }
2602 // cpuinfo not found or parsing failed, just print generic string. The entire
2603 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2604 #if defined(AARCH64)
2605 strncpy(cpuinfo, "AArch64", length);
2606 #elif defined(AMD64)
2607 strncpy(cpuinfo, "x86_64", length);
2608 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2609 strncpy(cpuinfo, "ARM", length);
2610 #elif defined(IA32)
2611 strncpy(cpuinfo, "x86_32", length);
2612 #elif defined(IA64)
2613 strncpy(cpuinfo, "IA64", length);
2614 #elif defined(PPC)
2615 strncpy(cpuinfo, "PPC64", length);
2616 #elif defined(S390)
2617 strncpy(cpuinfo, "S390", length);
2618 #elif defined(ZERO_LIBARCH)
2619 strncpy(cpuinfo, ZERO_LIBARCH, length);
2620 #else
2621 strncpy(cpuinfo, "unknown", length);
2622 #endif
2623 }
2624
2625 static void print_signal_handler(outputStream* st, int sig,
2626 char* buf, size_t buflen);
2627
2628 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2629 st->print_cr("Signal Handlers:");
2630 print_signal_handler(st, SIGSEGV, buf, buflen);
2631 print_signal_handler(st, SIGBUS , buf, buflen);
2632 print_signal_handler(st, SIGFPE , buf, buflen);
2633 print_signal_handler(st, SIGPIPE, buf, buflen);
2634 print_signal_handler(st, SIGXFSZ, buf, buflen);
2635 print_signal_handler(st, SIGILL , buf, buflen);
2636 print_signal_handler(st, SR_signum, buf, buflen);
2637 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2638 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2639 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2640 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2641 #if defined(PPC64)
2642 print_signal_handler(st, SIGTRAP, buf, buflen);
2643 #endif
2644 }
2645
2646 static char saved_jvm_path[MAXPATHLEN] = {0};
2647
2648 // Find the full path to the current module, libjvm.so
2649 void os::jvm_path(char *buf, jint buflen) {
2650 // Error checking.
2651 if (buflen < MAXPATHLEN) {
2652 assert(false, "must use a large-enough buffer");
2653 buf[0] = '\0';
2654 return;
2655 }
2656 // Lazy resolve the path to current module.
2657 if (saved_jvm_path[0] != 0) {
2658 strcpy(buf, saved_jvm_path);
2659 return;
2660 }
2661
2662 char dli_fname[MAXPATHLEN];
2663 bool ret = dll_address_to_library_name(
2664 CAST_FROM_FN_PTR(address, os::jvm_path),
2665 dli_fname, sizeof(dli_fname), NULL);
2666 assert(ret, "cannot locate libjvm");
2667 char *rp = NULL;
2668 if (ret && dli_fname[0] != '\0') {
2669 rp = os::Posix::realpath(dli_fname, buf, buflen);
2670 }
2671 if (rp == NULL) {
2672 return;
2673 }
2674
2675 if (Arguments::sun_java_launcher_is_altjvm()) {
2676 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2677 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2678 // If "/jre/lib/" appears at the right place in the string, then
2679 // assume we are installed in a JDK and we're done. Otherwise, check
2680 // for a JAVA_HOME environment variable and fix up the path so it
2681 // looks like libjvm.so is installed there (append a fake suffix
2682 // hotspot/libjvm.so).
2683 const char *p = buf + strlen(buf) - 1;
2684 for (int count = 0; p > buf && count < 5; ++count) {
2685 for (--p; p > buf && *p != '/'; --p)
2686 /* empty */ ;
2687 }
2688
2689 if (strncmp(p, "/jre/lib/", 9) != 0) {
2690 // Look for JAVA_HOME in the environment.
2691 char* java_home_var = ::getenv("JAVA_HOME");
2692 if (java_home_var != NULL && java_home_var[0] != 0) {
2693 char* jrelib_p;
2694 int len;
2695
2696 // Check the current module name "libjvm.so".
2697 p = strrchr(buf, '/');
2698 if (p == NULL) {
2699 return;
2700 }
2701 assert(strstr(p, "/libjvm") == p, "invalid library name");
2702
2703 rp = os::Posix::realpath(java_home_var, buf, buflen);
2704 if (rp == NULL) {
2705 return;
2706 }
2707
2708 // determine if this is a legacy image or modules image
2709 // modules image doesn't have "jre" subdirectory
2710 len = strlen(buf);
2711 assert(len < buflen, "Ran out of buffer room");
2712 jrelib_p = buf + len;
2713 snprintf(jrelib_p, buflen-len, "/jre/lib");
2714 if (0 != access(buf, F_OK)) {
2715 snprintf(jrelib_p, buflen-len, "/lib");
2716 }
2717
2718 if (0 == access(buf, F_OK)) {
2719 // Use current module name "libjvm.so"
2720 len = strlen(buf);
2721 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2722 } else {
2723 // Go back to path of .so
2724 rp = os::Posix::realpath(dli_fname, buf, buflen);
2725 if (rp == NULL) {
2726 return;
2727 }
2728 }
2729 }
2730 }
2731 }
2732
2733 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2734 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2735 }
2736
2737 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2738 // no prefix required, not even "_"
2739 }
2740
2741 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2742 // no suffix required
2743 }
2744
2745 ////////////////////////////////////////////////////////////////////////////////
2746 // sun.misc.Signal support
2747
2748 static void UserHandler(int sig, void *siginfo, void *context) {
2749 // Ctrl-C is pressed during error reporting, likely because the error
2750 // handler fails to abort. Let VM die immediately.
2751 if (sig == SIGINT && VMError::is_error_reported()) {
2752 os::die();
2753 }
2754
2755 os::signal_notify(sig);
2756 }
2757
2758 void* os::user_handler() {
2759 return CAST_FROM_FN_PTR(void*, UserHandler);
2760 }
2761
2762 extern "C" {
2763 typedef void (*sa_handler_t)(int);
2764 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2765 }
2766
2767 void* os::signal(int signal_number, void* handler) {
2768 struct sigaction sigAct, oldSigAct;
2769
2770 sigfillset(&(sigAct.sa_mask));
2771 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2772 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2773
2774 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2775 // -1 means registration failed
2776 return (void *)-1;
2777 }
2778
2779 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2780 }
2781
2782 void os::signal_raise(int signal_number) {
2783 ::raise(signal_number);
2784 }
2785
2786 // The following code is moved from os.cpp for making this
2787 // code platform specific, which it is by its very nature.
2788
2789 // Will be modified when max signal is changed to be dynamic
2790 int os::sigexitnum_pd() {
2791 return NSIG;
2792 }
2793
2794 // a counter for each possible signal value
2795 static volatile jint pending_signals[NSIG+1] = { 0 };
2796
2797 // Linux(POSIX) specific hand shaking semaphore.
2798 static Semaphore* sig_sem = NULL;
2799 static PosixSemaphore sr_semaphore;
2800
2801 static void jdk_misc_signal_init() {
2802 // Initialize signal structures
2803 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2804
2805 // Initialize signal semaphore
2806 sig_sem = new Semaphore();
2807 }
2808
2809 void os::signal_notify(int sig) {
2810 if (sig_sem != NULL) {
2811 Atomic::inc(&pending_signals[sig]);
2812 sig_sem->signal();
2813 } else {
2814 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2815 // initialization isn't called.
2816 assert(ReduceSignalUsage, "signal semaphore should be created");
2817 }
2818 }
2819
2820 static int check_pending_signals() {
2821 for (;;) {
2822 for (int i = 0; i < NSIG + 1; i++) {
2823 jint n = pending_signals[i];
2824 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) {
2825 return i;
2826 }
2827 }
2828 JavaThread *thread = JavaThread::current();
2829 ThreadBlockInVM tbivm(thread);
2830
2831 bool threadIsSuspended;
2832 do {
2833 thread->set_suspend_equivalent();
2834 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2835 sig_sem->wait();
2836
2837 // were we externally suspended while we were waiting?
2838 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2839 if (threadIsSuspended) {
2840 // The semaphore has been incremented, but while we were waiting
2841 // another thread suspended us. We don't want to continue running
2842 // while suspended because that would surprise the thread that
2843 // suspended us.
2844 sig_sem->signal();
2845
2846 thread->java_suspend_self();
2847 }
2848 } while (threadIsSuspended);
2849 }
2850 }
2851
2852 int os::signal_wait() {
2853 return check_pending_signals();
2854 }
2855
2856 ////////////////////////////////////////////////////////////////////////////////
2857 // Virtual Memory
2858
2859 int os::vm_page_size() {
2860 // Seems redundant as all get out
2861 assert(os::Linux::page_size() != -1, "must call os::init");
2862 return os::Linux::page_size();
2863 }
2864
2865 // Solaris allocates memory by pages.
2866 int os::vm_allocation_granularity() {
2867 assert(os::Linux::page_size() != -1, "must call os::init");
2868 return os::Linux::page_size();
2869 }
2870
2871 // Rationale behind this function:
2872 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2873 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2874 // samples for JITted code. Here we create private executable mapping over the code cache
2875 // and then we can use standard (well, almost, as mapping can change) way to provide
2876 // info for the reporting script by storing timestamp and location of symbol
2877 void linux_wrap_code(char* base, size_t size) {
2878 static volatile jint cnt = 0;
2879
2880 if (!UseOprofile) {
2881 return;
2882 }
2883
2884 char buf[PATH_MAX+1];
2885 int num = Atomic::add(&cnt, 1);
2886
2887 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2888 os::get_temp_directory(), os::current_process_id(), num);
2889 unlink(buf);
2890
2891 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2892
2893 if (fd != -1) {
2894 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2895 if (rv != (off_t)-1) {
2896 if (::write(fd, "", 1) == 1) {
2897 mmap(base, size,
2898 PROT_READ|PROT_WRITE|PROT_EXEC,
2899 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2900 }
2901 }
2902 ::close(fd);
2903 unlink(buf);
2904 }
2905 }
2906
2907 static bool recoverable_mmap_error(int err) {
2908 // See if the error is one we can let the caller handle. This
2909 // list of errno values comes from JBS-6843484. I can't find a
2910 // Linux man page that documents this specific set of errno
2911 // values so while this list currently matches Solaris, it may
2912 // change as we gain experience with this failure mode.
2913 switch (err) {
2914 case EBADF:
2915 case EINVAL:
2916 case ENOTSUP:
2917 // let the caller deal with these errors
2918 return true;
2919
2920 default:
2921 // Any remaining errors on this OS can cause our reserved mapping
2922 // to be lost. That can cause confusion where different data
2923 // structures think they have the same memory mapped. The worst
2924 // scenario is if both the VM and a library think they have the
2925 // same memory mapped.
2926 return false;
2927 }
2928 }
2929
2930 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2931 int err) {
2932 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2933 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2934 os::strerror(err), err);
2935 }
2936
2937 static void warn_fail_commit_memory(char* addr, size_t size,
2938 size_t alignment_hint, bool exec,
2939 int err) {
2940 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2941 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2942 alignment_hint, exec, os::strerror(err), err);
2943 }
2944
2945 // NOTE: Linux kernel does not really reserve the pages for us.
2946 // All it does is to check if there are enough free pages
2947 // left at the time of mmap(). This could be a potential
2948 // problem.
2949 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2950 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2951 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2952 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2953 if (res != (uintptr_t) MAP_FAILED) {
2954 if (UseNUMAInterleaving) {
2955 numa_make_global(addr, size);
2956 }
2957 return 0;
2958 }
2959
2960 int err = errno; // save errno from mmap() call above
2961
2962 if (!recoverable_mmap_error(err)) {
2963 warn_fail_commit_memory(addr, size, exec, err);
2964 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2965 }
2966
2967 return err;
2968 }
2969
2970 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2971 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2972 }
2973
2974 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2975 const char* mesg) {
2976 assert(mesg != NULL, "mesg must be specified");
2977 int err = os::Linux::commit_memory_impl(addr, size, exec);
2978 if (err != 0) {
2979 // the caller wants all commit errors to exit with the specified mesg:
2980 warn_fail_commit_memory(addr, size, exec, err);
2981 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2982 }
2983 }
2984
2985 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2986 #ifndef MAP_HUGETLB
2987 #define MAP_HUGETLB 0x40000
2988 #endif
2989
2990 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2991 #ifndef MADV_HUGEPAGE
2992 #define MADV_HUGEPAGE 14
2993 #endif
2994
2995 int os::Linux::commit_memory_impl(char* addr, size_t size,
2996 size_t alignment_hint, bool exec) {
2997 int err = os::Linux::commit_memory_impl(addr, size, exec);
2998 if (err == 0) {
2999 realign_memory(addr, size, alignment_hint);
3000 }
3001 return err;
3002 }
3003
3004 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
3005 bool exec) {
3006 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
3007 }
3008
3009 void os::pd_commit_memory_or_exit(char* addr, size_t size,
3010 size_t alignment_hint, bool exec,
3011 const char* mesg) {
3012 assert(mesg != NULL, "mesg must be specified");
3013 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
3014 if (err != 0) {
3015 // the caller wants all commit errors to exit with the specified mesg:
3016 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
3017 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
3018 }
3019 }
3020
3021 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
3022 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
3023 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
3024 // be supported or the memory may already be backed by huge pages.
3025 ::madvise(addr, bytes, MADV_HUGEPAGE);
3026 }
3027 }
3028
3029 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
3030 // This method works by doing an mmap over an existing mmaping and effectively discarding
3031 // the existing pages. However it won't work for SHM-based large pages that cannot be
3032 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
3033 // small pages on top of the SHM segment. This method always works for small pages, so we
3034 // allow that in any case.
3035 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
3036 commit_memory(addr, bytes, alignment_hint, !ExecMem);
3037 }
3038 }
3039
3040 void os::numa_make_global(char *addr, size_t bytes) {
3041 Linux::numa_interleave_memory(addr, bytes);
3042 }
3043
3044 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
3045 // bind policy to MPOL_PREFERRED for the current thread.
3046 #define USE_MPOL_PREFERRED 0
3047
3048 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
3049 // To make NUMA and large pages more robust when both enabled, we need to ease
3050 // the requirements on where the memory should be allocated. MPOL_BIND is the
3051 // default policy and it will force memory to be allocated on the specified
3052 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
3053 // the specified node, but will not force it. Using this policy will prevent
3054 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
3055 // free large pages.
3056 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
3057 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
3058 }
3059
3060 bool os::numa_topology_changed() { return false; }
3061
3062 size_t os::numa_get_groups_num() {
3063 // Return just the number of nodes in which it's possible to allocate memory
3064 // (in numa terminology, configured nodes).
3065 return Linux::numa_num_configured_nodes();
3066 }
3067
3068 int os::numa_get_group_id() {
3069 int cpu_id = Linux::sched_getcpu();
3070 if (cpu_id != -1) {
3071 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
3072 if (lgrp_id != -1) {
3073 return lgrp_id;
3074 }
3075 }
3076 return 0;
3077 }
3078
3079 int os::numa_get_group_id_for_address(const void* address) {
3080 void** pages = const_cast<void**>(&address);
3081 int id = -1;
3082
3083 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
3084 return -1;
3085 }
3086 if (id < 0) {
3087 return -1;
3088 }
3089 return id;
3090 }
3091
3092 int os::Linux::get_existing_num_nodes() {
3093 int node;
3094 int highest_node_number = Linux::numa_max_node();
3095 int num_nodes = 0;
3096
3097 // Get the total number of nodes in the system including nodes without memory.
3098 for (node = 0; node <= highest_node_number; node++) {
3099 if (is_node_in_existing_nodes(node)) {
3100 num_nodes++;
3101 }
3102 }
3103 return num_nodes;
3104 }
3105
3106 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
3107 int highest_node_number = Linux::numa_max_node();
3108 size_t i = 0;
3109
3110 // Map all node ids in which it is possible to allocate memory. Also nodes are
3111 // not always consecutively available, i.e. available from 0 to the highest
3112 // node number. If the nodes have been bound explicitly using numactl membind,
3113 // then allocate memory from those nodes only.
3114 for (int node = 0; node <= highest_node_number; node++) {
3115 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
3116 ids[i++] = node;
3117 }
3118 }
3119 return i;
3120 }
3121
3122 bool os::get_page_info(char *start, page_info* info) {
3123 return false;
3124 }
3125
3126 char *os::scan_pages(char *start, char* end, page_info* page_expected,
3127 page_info* page_found) {
3128 return end;
3129 }
3130
3131
3132 int os::Linux::sched_getcpu_syscall(void) {
3133 unsigned int cpu = 0;
3134 int retval = -1;
3135
3136 #if defined(IA32)
3137 #ifndef SYS_getcpu
3138 #define SYS_getcpu 318
3139 #endif
3140 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
3141 #elif defined(AMD64)
3142 // Unfortunately we have to bring all these macros here from vsyscall.h
3143 // to be able to compile on old linuxes.
3144 #define __NR_vgetcpu 2
3145 #define VSYSCALL_START (-10UL << 20)
3146 #define VSYSCALL_SIZE 1024
3147 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
3148 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
3149 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
3150 retval = vgetcpu(&cpu, NULL, NULL);
3151 #endif
3152
3153 return (retval == -1) ? retval : cpu;
3154 }
3155
3156 void os::Linux::sched_getcpu_init() {
3157 // sched_getcpu() should be in libc.
3158 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3159 dlsym(RTLD_DEFAULT, "sched_getcpu")));
3160
3161 // If it's not, try a direct syscall.
3162 if (sched_getcpu() == -1) {
3163 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3164 (void*)&sched_getcpu_syscall));
3165 }
3166
3167 if (sched_getcpu() == -1) {
3168 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
3169 }
3170 }
3171
3172 // Something to do with the numa-aware allocator needs these symbols
3173 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3174 extern "C" JNIEXPORT void numa_error(char *where) { }
3175
3176 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3177 // load symbol from base version instead.
3178 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3179 void *f = dlvsym(handle, name, "libnuma_1.1");
3180 if (f == NULL) {
3181 f = dlsym(handle, name);
3182 }
3183 return f;
3184 }
3185
3186 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3187 // Return NULL if the symbol is not defined in this particular version.
3188 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3189 return dlvsym(handle, name, "libnuma_1.2");
3190 }
3191
3192 bool os::Linux::libnuma_init() {
3193 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3194 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3195 if (handle != NULL) {
3196 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3197 libnuma_dlsym(handle, "numa_node_to_cpus")));
3198 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3199 libnuma_dlsym(handle, "numa_max_node")));
3200 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3201 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3202 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3203 libnuma_dlsym(handle, "numa_available")));
3204 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3205 libnuma_dlsym(handle, "numa_tonode_memory")));
3206 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3207 libnuma_dlsym(handle, "numa_interleave_memory")));
3208 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3209 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3210 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3211 libnuma_dlsym(handle, "numa_set_bind_policy")));
3212 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3213 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3214 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3215 libnuma_dlsym(handle, "numa_distance")));
3216 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3217 libnuma_v2_dlsym(handle, "numa_get_membind")));
3218 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3219 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3220 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3221 libnuma_dlsym(handle, "numa_move_pages")));
3222 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t,
3223 libnuma_dlsym(handle, "numa_set_preferred")));
3224
3225 if (numa_available() != -1) {
3226 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3227 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3228 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3229 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3230 set_numa_membind_bitmask(_numa_get_membind());
3231 // Create an index -> node mapping, since nodes are not always consecutive
3232 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3233 rebuild_nindex_to_node_map();
3234 // Create a cpu -> node mapping
3235 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3236 rebuild_cpu_to_node_map();
3237 return true;
3238 }
3239 }
3240 }
3241 return false;
3242 }
3243
3244 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3245 // Creating guard page is very expensive. Java thread has HotSpot
3246 // guard pages, only enable glibc guard page for non-Java threads.
3247 // (Remember: compiler thread is a Java thread, too!)
3248 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3249 }
3250
3251 void os::Linux::rebuild_nindex_to_node_map() {
3252 int highest_node_number = Linux::numa_max_node();
3253
3254 nindex_to_node()->clear();
3255 for (int node = 0; node <= highest_node_number; node++) {
3256 if (Linux::is_node_in_existing_nodes(node)) {
3257 nindex_to_node()->append(node);
3258 }
3259 }
3260 }
3261
3262 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3263 // The table is later used in get_node_by_cpu().
3264 void os::Linux::rebuild_cpu_to_node_map() {
3265 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3266 // in libnuma (possible values are starting from 16,
3267 // and continuing up with every other power of 2, but less
3268 // than the maximum number of CPUs supported by kernel), and
3269 // is a subject to change (in libnuma version 2 the requirements
3270 // are more reasonable) we'll just hardcode the number they use
3271 // in the library.
3272 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3273
3274 size_t cpu_num = processor_count();
3275 size_t cpu_map_size = NCPUS / BitsPerCLong;
3276 size_t cpu_map_valid_size =
3277 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3278
3279 cpu_to_node()->clear();
3280 cpu_to_node()->at_grow(cpu_num - 1);
3281
3282 size_t node_num = get_existing_num_nodes();
3283
3284 int distance = 0;
3285 int closest_distance = INT_MAX;
3286 int closest_node = 0;
3287 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3288 for (size_t i = 0; i < node_num; i++) {
3289 // Check if node is configured (not a memory-less node). If it is not, find
3290 // the closest configured node. Check also if node is bound, i.e. it's allowed
3291 // to allocate memory from the node. If it's not allowed, map cpus in that node
3292 // to the closest node from which memory allocation is allowed.
3293 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3294 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3295 closest_distance = INT_MAX;
3296 // Check distance from all remaining nodes in the system. Ignore distance
3297 // from itself, from another non-configured node, and from another non-bound
3298 // node.
3299 for (size_t m = 0; m < node_num; m++) {
3300 if (m != i &&
3301 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3302 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3303 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3304 // If a closest node is found, update. There is always at least one
3305 // configured and bound node in the system so there is always at least
3306 // one node close.
3307 if (distance != 0 && distance < closest_distance) {
3308 closest_distance = distance;
3309 closest_node = nindex_to_node()->at(m);
3310 }
3311 }
3312 }
3313 } else {
3314 // Current node is already a configured node.
3315 closest_node = nindex_to_node()->at(i);
3316 }
3317
3318 // Get cpus from the original node and map them to the closest node. If node
3319 // is a configured node (not a memory-less node), then original node and
3320 // closest node are the same.
3321 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3322 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3323 if (cpu_map[j] != 0) {
3324 for (size_t k = 0; k < BitsPerCLong; k++) {
3325 if (cpu_map[j] & (1UL << k)) {
3326 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3327 }
3328 }
3329 }
3330 }
3331 }
3332 }
3333 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3334 }
3335
3336 int os::Linux::get_node_by_cpu(int cpu_id) {
3337 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3338 return cpu_to_node()->at(cpu_id);
3339 }
3340 return -1;
3341 }
3342
3343 GrowableArray<int>* os::Linux::_cpu_to_node;
3344 GrowableArray<int>* os::Linux::_nindex_to_node;
3345 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3346 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3347 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3348 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3349 os::Linux::numa_available_func_t os::Linux::_numa_available;
3350 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3351 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3352 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3353 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3354 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3355 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3356 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3357 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3358 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3359 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred;
3360 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3361 unsigned long* os::Linux::_numa_all_nodes;
3362 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3363 struct bitmask* os::Linux::_numa_nodes_ptr;
3364 struct bitmask* os::Linux::_numa_interleave_bitmask;
3365 struct bitmask* os::Linux::_numa_membind_bitmask;
3366
3367 bool os::pd_uncommit_memory(char* addr, size_t size) {
3368 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3369 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3370 return res != (uintptr_t) MAP_FAILED;
3371 }
3372
3373 static address get_stack_commited_bottom(address bottom, size_t size) {
3374 address nbot = bottom;
3375 address ntop = bottom + size;
3376
3377 size_t page_sz = os::vm_page_size();
3378 unsigned pages = size / page_sz;
3379
3380 unsigned char vec[1];
3381 unsigned imin = 1, imax = pages + 1, imid;
3382 int mincore_return_value = 0;
3383
3384 assert(imin <= imax, "Unexpected page size");
3385
3386 while (imin < imax) {
3387 imid = (imax + imin) / 2;
3388 nbot = ntop - (imid * page_sz);
3389
3390 // Use a trick with mincore to check whether the page is mapped or not.
3391 // mincore sets vec to 1 if page resides in memory and to 0 if page
3392 // is swapped output but if page we are asking for is unmapped
3393 // it returns -1,ENOMEM
3394 mincore_return_value = mincore(nbot, page_sz, vec);
3395
3396 if (mincore_return_value == -1) {
3397 // Page is not mapped go up
3398 // to find first mapped page
3399 if (errno != EAGAIN) {
3400 assert(errno == ENOMEM, "Unexpected mincore errno");
3401 imax = imid;
3402 }
3403 } else {
3404 // Page is mapped go down
3405 // to find first not mapped page
3406 imin = imid + 1;
3407 }
3408 }
3409
3410 nbot = nbot + page_sz;
3411
3412 // Adjust stack bottom one page up if last checked page is not mapped
3413 if (mincore_return_value == -1) {
3414 nbot = nbot + page_sz;
3415 }
3416
3417 return nbot;
3418 }
3419
3420 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3421 int mincore_return_value;
3422 const size_t stripe = 1024; // query this many pages each time
3423 unsigned char vec[stripe + 1];
3424 // set a guard
3425 vec[stripe] = 'X';
3426
3427 const size_t page_sz = os::vm_page_size();
3428 size_t pages = size / page_sz;
3429
3430 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3431 assert(is_aligned(size, page_sz), "Size must be page aligned");
3432
3433 committed_start = NULL;
3434
3435 int loops = (pages + stripe - 1) / stripe;
3436 int committed_pages = 0;
3437 address loop_base = start;
3438 bool found_range = false;
3439
3440 for (int index = 0; index < loops && !found_range; index ++) {
3441 assert(pages > 0, "Nothing to do");
3442 int pages_to_query = (pages >= stripe) ? stripe : pages;
3443 pages -= pages_to_query;
3444
3445 // Get stable read
3446 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3447
3448 // During shutdown, some memory goes away without properly notifying NMT,
3449 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3450 // Bailout and return as not committed for now.
3451 if (mincore_return_value == -1 && errno == ENOMEM) {
3452 return false;
3453 }
3454
3455 assert(vec[stripe] == 'X', "overflow guard");
3456 assert(mincore_return_value == 0, "Range must be valid");
3457 // Process this stripe
3458 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3459 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3460 // End of current contiguous region
3461 if (committed_start != NULL) {
3462 found_range = true;
3463 break;
3464 }
3465 } else { // committed
3466 // Start of region
3467 if (committed_start == NULL) {
3468 committed_start = loop_base + page_sz * vecIdx;
3469 }
3470 committed_pages ++;
3471 }
3472 }
3473
3474 loop_base += pages_to_query * page_sz;
3475 }
3476
3477 if (committed_start != NULL) {
3478 assert(committed_pages > 0, "Must have committed region");
3479 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3480 assert(committed_start >= start && committed_start < start + size, "Out of range");
3481 committed_size = page_sz * committed_pages;
3482 return true;
3483 } else {
3484 assert(committed_pages == 0, "Should not have committed region");
3485 return false;
3486 }
3487 }
3488
3489
3490 // Linux uses a growable mapping for the stack, and if the mapping for
3491 // the stack guard pages is not removed when we detach a thread the
3492 // stack cannot grow beyond the pages where the stack guard was
3493 // mapped. If at some point later in the process the stack expands to
3494 // that point, the Linux kernel cannot expand the stack any further
3495 // because the guard pages are in the way, and a segfault occurs.
3496 //
3497 // However, it's essential not to split the stack region by unmapping
3498 // a region (leaving a hole) that's already part of the stack mapping,
3499 // so if the stack mapping has already grown beyond the guard pages at
3500 // the time we create them, we have to truncate the stack mapping.
3501 // So, we need to know the extent of the stack mapping when
3502 // create_stack_guard_pages() is called.
3503
3504 // We only need this for stacks that are growable: at the time of
3505 // writing thread stacks don't use growable mappings (i.e. those
3506 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3507 // only applies to the main thread.
3508
3509 // If the (growable) stack mapping already extends beyond the point
3510 // where we're going to put our guard pages, truncate the mapping at
3511 // that point by munmap()ping it. This ensures that when we later
3512 // munmap() the guard pages we don't leave a hole in the stack
3513 // mapping. This only affects the main/primordial thread
3514
3515 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3516 if (os::is_primordial_thread()) {
3517 // As we manually grow stack up to bottom inside create_attached_thread(),
3518 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3519 // we don't need to do anything special.
3520 // Check it first, before calling heavy function.
3521 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3522 unsigned char vec[1];
3523
3524 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3525 // Fallback to slow path on all errors, including EAGAIN
3526 stack_extent = (uintptr_t) get_stack_commited_bottom(
3527 os::Linux::initial_thread_stack_bottom(),
3528 (size_t)addr - stack_extent);
3529 }
3530
3531 if (stack_extent < (uintptr_t)addr) {
3532 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3533 }
3534 }
3535
3536 return os::commit_memory(addr, size, !ExecMem);
3537 }
3538
3539 // If this is a growable mapping, remove the guard pages entirely by
3540 // munmap()ping them. If not, just call uncommit_memory(). This only
3541 // affects the main/primordial thread, but guard against future OS changes.
3542 // It's safe to always unmap guard pages for primordial thread because we
3543 // always place it right after end of the mapped region.
3544
3545 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3546 uintptr_t stack_extent, stack_base;
3547
3548 if (os::is_primordial_thread()) {
3549 return ::munmap(addr, size) == 0;
3550 }
3551
3552 return os::uncommit_memory(addr, size);
3553 }
3554
3555 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3556 // at 'requested_addr'. If there are existing memory mappings at the same
3557 // location, however, they will be overwritten. If 'fixed' is false,
3558 // 'requested_addr' is only treated as a hint, the return value may or
3559 // may not start from the requested address. Unlike Linux mmap(), this
3560 // function returns NULL to indicate failure.
3561 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3562 char * addr;
3563 int flags;
3564
3565 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3566 if (fixed) {
3567 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3568 flags |= MAP_FIXED;
3569 }
3570
3571 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3572 // touch an uncommitted page. Otherwise, the read/write might
3573 // succeed if we have enough swap space to back the physical page.
3574 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3575 flags, -1, 0);
3576
3577 return addr == MAP_FAILED ? NULL : addr;
3578 }
3579
3580 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3581 // (req_addr != NULL) or with a given alignment.
3582 // - bytes shall be a multiple of alignment.
3583 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3584 // - alignment sets the alignment at which memory shall be allocated.
3585 // It must be a multiple of allocation granularity.
3586 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3587 // req_addr or NULL.
3588 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3589
3590 size_t extra_size = bytes;
3591 if (req_addr == NULL && alignment > 0) {
3592 extra_size += alignment;
3593 }
3594
3595 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3596 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3597 -1, 0);
3598 if (start == MAP_FAILED) {
3599 start = NULL;
3600 } else {
3601 if (req_addr != NULL) {
3602 if (start != req_addr) {
3603 ::munmap(start, extra_size);
3604 start = NULL;
3605 }
3606 } else {
3607 char* const start_aligned = align_up(start, alignment);
3608 char* const end_aligned = start_aligned + bytes;
3609 char* const end = start + extra_size;
3610 if (start_aligned > start) {
3611 ::munmap(start, start_aligned - start);
3612 }
3613 if (end_aligned < end) {
3614 ::munmap(end_aligned, end - end_aligned);
3615 }
3616 start = start_aligned;
3617 }
3618 }
3619 return start;
3620 }
3621
3622 static int anon_munmap(char * addr, size_t size) {
3623 return ::munmap(addr, size) == 0;
3624 }
3625
3626 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3627 size_t alignment_hint) {
3628 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3629 }
3630
3631 bool os::pd_release_memory(char* addr, size_t size) {
3632 return anon_munmap(addr, size);
3633 }
3634
3635 static bool linux_mprotect(char* addr, size_t size, int prot) {
3636 // Linux wants the mprotect address argument to be page aligned.
3637 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3638
3639 // According to SUSv3, mprotect() should only be used with mappings
3640 // established by mmap(), and mmap() always maps whole pages. Unaligned
3641 // 'addr' likely indicates problem in the VM (e.g. trying to change
3642 // protection of malloc'ed or statically allocated memory). Check the
3643 // caller if you hit this assert.
3644 assert(addr == bottom, "sanity check");
3645
3646 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3647 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3648 return ::mprotect(bottom, size, prot) == 0;
3649 }
3650
3651 // Set protections specified
3652 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3653 bool is_committed) {
3654 unsigned int p = 0;
3655 switch (prot) {
3656 case MEM_PROT_NONE: p = PROT_NONE; break;
3657 case MEM_PROT_READ: p = PROT_READ; break;
3658 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3659 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3660 default:
3661 ShouldNotReachHere();
3662 }
3663 // is_committed is unused.
3664 return linux_mprotect(addr, bytes, p);
3665 }
3666
3667 bool os::guard_memory(char* addr, size_t size) {
3668 return linux_mprotect(addr, size, PROT_NONE);
3669 }
3670
3671 bool os::unguard_memory(char* addr, size_t size) {
3672 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3673 }
3674
3675 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3676 size_t page_size) {
3677 bool result = false;
3678 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3679 MAP_ANONYMOUS|MAP_PRIVATE,
3680 -1, 0);
3681 if (p != MAP_FAILED) {
3682 void *aligned_p = align_up(p, page_size);
3683
3684 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3685
3686 munmap(p, page_size * 2);
3687 }
3688
3689 if (warn && !result) {
3690 warning("TransparentHugePages is not supported by the operating system.");
3691 }
3692
3693 return result;
3694 }
3695
3696 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3697 bool result = false;
3698 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3699 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3700 -1, 0);
3701
3702 if (p != MAP_FAILED) {
3703 // We don't know if this really is a huge page or not.
3704 FILE *fp = fopen("/proc/self/maps", "r");
3705 if (fp) {
3706 while (!feof(fp)) {
3707 char chars[257];
3708 long x = 0;
3709 if (fgets(chars, sizeof(chars), fp)) {
3710 if (sscanf(chars, "%lx-%*x", &x) == 1
3711 && x == (long)p) {
3712 if (strstr (chars, "hugepage")) {
3713 result = true;
3714 break;
3715 }
3716 }
3717 }
3718 }
3719 fclose(fp);
3720 }
3721 munmap(p, page_size);
3722 }
3723
3724 if (warn && !result) {
3725 warning("HugeTLBFS is not supported by the operating system.");
3726 }
3727
3728 return result;
3729 }
3730
3731 // From the coredump_filter documentation:
3732 //
3733 // - (bit 0) anonymous private memory
3734 // - (bit 1) anonymous shared memory
3735 // - (bit 2) file-backed private memory
3736 // - (bit 3) file-backed shared memory
3737 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3738 // effective only if the bit 2 is cleared)
3739 // - (bit 5) hugetlb private memory
3740 // - (bit 6) hugetlb shared memory
3741 // - (bit 7) dax private memory
3742 // - (bit 8) dax shared memory
3743 //
3744 static void set_coredump_filter(CoredumpFilterBit bit) {
3745 FILE *f;
3746 long cdm;
3747
3748 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3749 return;
3750 }
3751
3752 if (fscanf(f, "%lx", &cdm) != 1) {
3753 fclose(f);
3754 return;
3755 }
3756
3757 long saved_cdm = cdm;
3758 rewind(f);
3759 cdm |= bit;
3760
3761 if (cdm != saved_cdm) {
3762 fprintf(f, "%#lx", cdm);
3763 }
3764
3765 fclose(f);
3766 }
3767
3768 // Large page support
3769
3770 static size_t _large_page_size = 0;
3771
3772 size_t os::Linux::find_large_page_size() {
3773 size_t large_page_size = 0;
3774
3775 // large_page_size on Linux is used to round up heap size. x86 uses either
3776 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3777 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3778 // page as large as 256M.
3779 //
3780 // Here we try to figure out page size by parsing /proc/meminfo and looking
3781 // for a line with the following format:
3782 // Hugepagesize: 2048 kB
3783 //
3784 // If we can't determine the value (e.g. /proc is not mounted, or the text
3785 // format has been changed), we'll use the largest page size supported by
3786 // the processor.
3787
3788 #ifndef ZERO
3789 large_page_size =
3790 AARCH64_ONLY(2 * M)
3791 AMD64_ONLY(2 * M)
3792 ARM32_ONLY(2 * M)
3793 IA32_ONLY(4 * M)
3794 IA64_ONLY(256 * M)
3795 PPC_ONLY(4 * M)
3796 S390_ONLY(1 * M);
3797 #endif // ZERO
3798
3799 FILE *fp = fopen("/proc/meminfo", "r");
3800 if (fp) {
3801 while (!feof(fp)) {
3802 int x = 0;
3803 char buf[16];
3804 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3805 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3806 large_page_size = x * K;
3807 break;
3808 }
3809 } else {
3810 // skip to next line
3811 for (;;) {
3812 int ch = fgetc(fp);
3813 if (ch == EOF || ch == (int)'\n') break;
3814 }
3815 }
3816 }
3817 fclose(fp);
3818 }
3819
3820 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3821 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3822 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3823 proper_unit_for_byte_size(large_page_size));
3824 }
3825
3826 return large_page_size;
3827 }
3828
3829 size_t os::Linux::setup_large_page_size() {
3830 _large_page_size = Linux::find_large_page_size();
3831 const size_t default_page_size = (size_t)Linux::page_size();
3832 if (_large_page_size > default_page_size) {
3833 _page_sizes[0] = _large_page_size;
3834 _page_sizes[1] = default_page_size;
3835 _page_sizes[2] = 0;
3836 }
3837
3838 return _large_page_size;
3839 }
3840
3841 bool os::Linux::setup_large_page_type(size_t page_size) {
3842 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3843 FLAG_IS_DEFAULT(UseSHM) &&
3844 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3845
3846 // The type of large pages has not been specified by the user.
3847
3848 // Try UseHugeTLBFS and then UseSHM.
3849 UseHugeTLBFS = UseSHM = true;
3850
3851 // Don't try UseTransparentHugePages since there are known
3852 // performance issues with it turned on. This might change in the future.
3853 UseTransparentHugePages = false;
3854 }
3855
3856 if (UseTransparentHugePages) {
3857 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3858 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3859 UseHugeTLBFS = false;
3860 UseSHM = false;
3861 return true;
3862 }
3863 UseTransparentHugePages = false;
3864 }
3865
3866 if (UseHugeTLBFS) {
3867 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3868 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3869 UseSHM = false;
3870 return true;
3871 }
3872 UseHugeTLBFS = false;
3873 }
3874
3875 return UseSHM;
3876 }
3877
3878 void os::large_page_init() {
3879 if (!UseLargePages &&
3880 !UseTransparentHugePages &&
3881 !UseHugeTLBFS &&
3882 !UseSHM) {
3883 // Not using large pages.
3884 return;
3885 }
3886
3887 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3888 // The user explicitly turned off large pages.
3889 // Ignore the rest of the large pages flags.
3890 UseTransparentHugePages = false;
3891 UseHugeTLBFS = false;
3892 UseSHM = false;
3893 return;
3894 }
3895
3896 size_t large_page_size = Linux::setup_large_page_size();
3897 UseLargePages = Linux::setup_large_page_type(large_page_size);
3898
3899 set_coredump_filter(LARGEPAGES_BIT);
3900 }
3901
3902 #ifndef SHM_HUGETLB
3903 #define SHM_HUGETLB 04000
3904 #endif
3905
3906 #define shm_warning_format(format, ...) \
3907 do { \
3908 if (UseLargePages && \
3909 (!FLAG_IS_DEFAULT(UseLargePages) || \
3910 !FLAG_IS_DEFAULT(UseSHM) || \
3911 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3912 warning(format, __VA_ARGS__); \
3913 } \
3914 } while (0)
3915
3916 #define shm_warning(str) shm_warning_format("%s", str)
3917
3918 #define shm_warning_with_errno(str) \
3919 do { \
3920 int err = errno; \
3921 shm_warning_format(str " (error = %d)", err); \
3922 } while (0)
3923
3924 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3925 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3926
3927 if (!is_aligned(alignment, SHMLBA)) {
3928 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3929 return NULL;
3930 }
3931
3932 // To ensure that we get 'alignment' aligned memory from shmat,
3933 // we pre-reserve aligned virtual memory and then attach to that.
3934
3935 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3936 if (pre_reserved_addr == NULL) {
3937 // Couldn't pre-reserve aligned memory.
3938 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3939 return NULL;
3940 }
3941
3942 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3943 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3944
3945 if ((intptr_t)addr == -1) {
3946 int err = errno;
3947 shm_warning_with_errno("Failed to attach shared memory.");
3948
3949 assert(err != EACCES, "Unexpected error");
3950 assert(err != EIDRM, "Unexpected error");
3951 assert(err != EINVAL, "Unexpected error");
3952
3953 // Since we don't know if the kernel unmapped the pre-reserved memory area
3954 // we can't unmap it, since that would potentially unmap memory that was
3955 // mapped from other threads.
3956 return NULL;
3957 }
3958
3959 return addr;
3960 }
3961
3962 static char* shmat_at_address(int shmid, char* req_addr) {
3963 if (!is_aligned(req_addr, SHMLBA)) {
3964 assert(false, "Requested address needs to be SHMLBA aligned");
3965 return NULL;
3966 }
3967
3968 char* addr = (char*)shmat(shmid, req_addr, 0);
3969
3970 if ((intptr_t)addr == -1) {
3971 shm_warning_with_errno("Failed to attach shared memory.");
3972 return NULL;
3973 }
3974
3975 return addr;
3976 }
3977
3978 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3979 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3980 if (req_addr != NULL) {
3981 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3982 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3983 return shmat_at_address(shmid, req_addr);
3984 }
3985
3986 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3987 // return large page size aligned memory addresses when req_addr == NULL.
3988 // However, if the alignment is larger than the large page size, we have
3989 // to manually ensure that the memory returned is 'alignment' aligned.
3990 if (alignment > os::large_page_size()) {
3991 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3992 return shmat_with_alignment(shmid, bytes, alignment);
3993 } else {
3994 return shmat_at_address(shmid, NULL);
3995 }
3996 }
3997
3998 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3999 char* req_addr, bool exec) {
4000 // "exec" is passed in but not used. Creating the shared image for
4001 // the code cache doesn't have an SHM_X executable permission to check.
4002 assert(UseLargePages && UseSHM, "only for SHM large pages");
4003 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4004 assert(is_aligned(req_addr, alignment), "Unaligned address");
4005
4006 if (!is_aligned(bytes, os::large_page_size())) {
4007 return NULL; // Fallback to small pages.
4008 }
4009
4010 // Create a large shared memory region to attach to based on size.
4011 // Currently, size is the total size of the heap.
4012 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
4013 if (shmid == -1) {
4014 // Possible reasons for shmget failure:
4015 // 1. shmmax is too small for Java heap.
4016 // > check shmmax value: cat /proc/sys/kernel/shmmax
4017 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
4018 // 2. not enough large page memory.
4019 // > check available large pages: cat /proc/meminfo
4020 // > increase amount of large pages:
4021 // echo new_value > /proc/sys/vm/nr_hugepages
4022 // Note 1: different Linux may use different name for this property,
4023 // e.g. on Redhat AS-3 it is "hugetlb_pool".
4024 // Note 2: it's possible there's enough physical memory available but
4025 // they are so fragmented after a long run that they can't
4026 // coalesce into large pages. Try to reserve large pages when
4027 // the system is still "fresh".
4028 shm_warning_with_errno("Failed to reserve shared memory.");
4029 return NULL;
4030 }
4031
4032 // Attach to the region.
4033 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
4034
4035 // Remove shmid. If shmat() is successful, the actual shared memory segment
4036 // will be deleted when it's detached by shmdt() or when the process
4037 // terminates. If shmat() is not successful this will remove the shared
4038 // segment immediately.
4039 shmctl(shmid, IPC_RMID, NULL);
4040
4041 return addr;
4042 }
4043
4044 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
4045 int error) {
4046 assert(error == ENOMEM, "Only expect to fail if no memory is available");
4047
4048 bool warn_on_failure = UseLargePages &&
4049 (!FLAG_IS_DEFAULT(UseLargePages) ||
4050 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
4051 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
4052
4053 if (warn_on_failure) {
4054 char msg[128];
4055 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
4056 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
4057 warning("%s", msg);
4058 }
4059 }
4060
4061 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
4062 char* req_addr,
4063 bool exec) {
4064 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4065 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
4066 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4067
4068 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4069 char* addr = (char*)::mmap(req_addr, bytes, prot,
4070 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
4071 -1, 0);
4072
4073 if (addr == MAP_FAILED) {
4074 warn_on_large_pages_failure(req_addr, bytes, errno);
4075 return NULL;
4076 }
4077
4078 assert(is_aligned(addr, os::large_page_size()), "Must be");
4079
4080 return addr;
4081 }
4082
4083 // Reserve memory using mmap(MAP_HUGETLB).
4084 // - bytes shall be a multiple of alignment.
4085 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
4086 // - alignment sets the alignment at which memory shall be allocated.
4087 // It must be a multiple of allocation granularity.
4088 // Returns address of memory or NULL. If req_addr was not NULL, will only return
4089 // req_addr or NULL.
4090 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
4091 size_t alignment,
4092 char* req_addr,
4093 bool exec) {
4094 size_t large_page_size = os::large_page_size();
4095 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
4096
4097 assert(is_aligned(req_addr, alignment), "Must be");
4098 assert(is_aligned(bytes, alignment), "Must be");
4099
4100 // First reserve - but not commit - the address range in small pages.
4101 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
4102
4103 if (start == NULL) {
4104 return NULL;
4105 }
4106
4107 assert(is_aligned(start, alignment), "Must be");
4108
4109 char* end = start + bytes;
4110
4111 // Find the regions of the allocated chunk that can be promoted to large pages.
4112 char* lp_start = align_up(start, large_page_size);
4113 char* lp_end = align_down(end, large_page_size);
4114
4115 size_t lp_bytes = lp_end - lp_start;
4116
4117 assert(is_aligned(lp_bytes, large_page_size), "Must be");
4118
4119 if (lp_bytes == 0) {
4120 // The mapped region doesn't even span the start and the end of a large page.
4121 // Fall back to allocate a non-special area.
4122 ::munmap(start, end - start);
4123 return NULL;
4124 }
4125
4126 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4127
4128 void* result;
4129
4130 // Commit small-paged leading area.
4131 if (start != lp_start) {
4132 result = ::mmap(start, lp_start - start, prot,
4133 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4134 -1, 0);
4135 if (result == MAP_FAILED) {
4136 ::munmap(lp_start, end - lp_start);
4137 return NULL;
4138 }
4139 }
4140
4141 // Commit large-paged area.
4142 result = ::mmap(lp_start, lp_bytes, prot,
4143 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
4144 -1, 0);
4145 if (result == MAP_FAILED) {
4146 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
4147 // If the mmap above fails, the large pages region will be unmapped and we
4148 // have regions before and after with small pages. Release these regions.
4149 //
4150 // | mapped | unmapped | mapped |
4151 // ^ ^ ^ ^
4152 // start lp_start lp_end end
4153 //
4154 ::munmap(start, lp_start - start);
4155 ::munmap(lp_end, end - lp_end);
4156 return NULL;
4157 }
4158
4159 // Commit small-paged trailing area.
4160 if (lp_end != end) {
4161 result = ::mmap(lp_end, end - lp_end, prot,
4162 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4163 -1, 0);
4164 if (result == MAP_FAILED) {
4165 ::munmap(start, lp_end - start);
4166 return NULL;
4167 }
4168 }
4169
4170 return start;
4171 }
4172
4173 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4174 size_t alignment,
4175 char* req_addr,
4176 bool exec) {
4177 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4178 assert(is_aligned(req_addr, alignment), "Must be");
4179 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4180 assert(is_power_of_2(os::large_page_size()), "Must be");
4181 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
4182
4183 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
4184 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
4185 } else {
4186 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
4187 }
4188 }
4189
4190 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment,
4191 char* req_addr, bool exec) {
4192 assert(UseLargePages, "only for large pages");
4193
4194 char* addr;
4195 if (UseSHM) {
4196 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4197 } else {
4198 assert(UseHugeTLBFS, "must be");
4199 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4200 }
4201
4202 if (addr != NULL) {
4203 if (UseNUMAInterleaving) {
4204 numa_make_global(addr, bytes);
4205 }
4206 }
4207
4208 return addr;
4209 }
4210
4211 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4212 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4213 return shmdt(base) == 0;
4214 }
4215
4216 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4217 return pd_release_memory(base, bytes);
4218 }
4219
4220 bool os::pd_release_memory_special(char* base, size_t bytes) {
4221 assert(UseLargePages, "only for large pages");
4222 bool res;
4223
4224 if (UseSHM) {
4225 res = os::Linux::release_memory_special_shm(base, bytes);
4226 } else {
4227 assert(UseHugeTLBFS, "must be");
4228 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4229 }
4230 return res;
4231 }
4232
4233 size_t os::large_page_size() {
4234 return _large_page_size;
4235 }
4236
4237 // With SysV SHM the entire memory region must be allocated as shared
4238 // memory.
4239 // HugeTLBFS allows application to commit large page memory on demand.
4240 // However, when committing memory with HugeTLBFS fails, the region
4241 // that was supposed to be committed will lose the old reservation
4242 // and allow other threads to steal that memory region. Because of this
4243 // behavior we can't commit HugeTLBFS memory.
4244 bool os::can_commit_large_page_memory() {
4245 return UseTransparentHugePages;
4246 }
4247
4248 bool os::can_execute_large_page_memory() {
4249 return UseTransparentHugePages || UseHugeTLBFS;
4250 }
4251
4252 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4253 assert(file_desc >= 0, "file_desc is not valid");
4254 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4255 if (result != NULL) {
4256 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4257 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4258 }
4259 }
4260 return result;
4261 }
4262
4263 // Reserve memory at an arbitrary address, only if that area is
4264 // available (and not reserved for something else).
4265
4266 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4267 // Assert only that the size is a multiple of the page size, since
4268 // that's all that mmap requires, and since that's all we really know
4269 // about at this low abstraction level. If we need higher alignment,
4270 // we can either pass an alignment to this method or verify alignment
4271 // in one of the methods further up the call chain. See bug 5044738.
4272 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4273
4274 // Repeatedly allocate blocks until the block is allocated at the
4275 // right spot.
4276
4277 // Linux mmap allows caller to pass an address as hint; give it a try first,
4278 // if kernel honors the hint then we can return immediately.
4279 char * addr = anon_mmap(requested_addr, bytes, false);
4280 if (addr == requested_addr) {
4281 return requested_addr;
4282 }
4283
4284 if (addr != NULL) {
4285 // mmap() is successful but it fails to reserve at the requested address
4286 anon_munmap(addr, bytes);
4287 }
4288
4289 return NULL;
4290 }
4291
4292 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4293 void os::infinite_sleep() {
4294 while (true) { // sleep forever ...
4295 ::sleep(100); // ... 100 seconds at a time
4296 }
4297 }
4298
4299 // Used to convert frequent JVM_Yield() to nops
4300 bool os::dont_yield() {
4301 return DontYieldALot;
4302 }
4303
4304 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4305 // actually give up the CPU. Since skip buddy (v2.6.28):
4306 //
4307 // * Sets the yielding task as skip buddy for current CPU's run queue.
4308 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4309 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4310 //
4311 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4312 // getting re-scheduled immediately.
4313 //
4314 void os::naked_yield() {
4315 sched_yield();
4316 }
4317
4318 ////////////////////////////////////////////////////////////////////////////////
4319 // thread priority support
4320
4321 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4322 // only supports dynamic priority, static priority must be zero. For real-time
4323 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4324 // However, for large multi-threaded applications, SCHED_RR is not only slower
4325 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4326 // of 5 runs - Sep 2005).
4327 //
4328 // The following code actually changes the niceness of kernel-thread/LWP. It
4329 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4330 // not the entire user process, and user level threads are 1:1 mapped to kernel
4331 // threads. It has always been the case, but could change in the future. For
4332 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4333 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4334 // (e.g., root privilege or CAP_SYS_NICE capability).
4335
4336 int os::java_to_os_priority[CriticalPriority + 1] = {
4337 19, // 0 Entry should never be used
4338
4339 4, // 1 MinPriority
4340 3, // 2
4341 2, // 3
4342
4343 1, // 4
4344 0, // 5 NormPriority
4345 -1, // 6
4346
4347 -2, // 7
4348 -3, // 8
4349 -4, // 9 NearMaxPriority
4350
4351 -5, // 10 MaxPriority
4352
4353 -5 // 11 CriticalPriority
4354 };
4355
4356 static int prio_init() {
4357 if (ThreadPriorityPolicy == 1) {
4358 if (geteuid() != 0) {
4359 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) {
4360 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4361 "e.g., being the root user. If the necessary permission is not " \
4362 "possessed, changes to priority will be silently ignored.");
4363 }
4364 }
4365 }
4366 if (UseCriticalJavaThreadPriority) {
4367 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4368 }
4369 return 0;
4370 }
4371
4372 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4373 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4374
4375 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4376 return (ret == 0) ? OS_OK : OS_ERR;
4377 }
4378
4379 OSReturn os::get_native_priority(const Thread* const thread,
4380 int *priority_ptr) {
4381 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4382 *priority_ptr = java_to_os_priority[NormPriority];
4383 return OS_OK;
4384 }
4385
4386 errno = 0;
4387 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4388 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4389 }
4390
4391 ////////////////////////////////////////////////////////////////////////////////
4392 // suspend/resume support
4393
4394 // The low-level signal-based suspend/resume support is a remnant from the
4395 // old VM-suspension that used to be for java-suspension, safepoints etc,
4396 // within hotspot. Currently used by JFR's OSThreadSampler
4397 //
4398 // The remaining code is greatly simplified from the more general suspension
4399 // code that used to be used.
4400 //
4401 // The protocol is quite simple:
4402 // - suspend:
4403 // - sends a signal to the target thread
4404 // - polls the suspend state of the osthread using a yield loop
4405 // - target thread signal handler (SR_handler) sets suspend state
4406 // and blocks in sigsuspend until continued
4407 // - resume:
4408 // - sets target osthread state to continue
4409 // - sends signal to end the sigsuspend loop in the SR_handler
4410 //
4411 // Note that the SR_lock plays no role in this suspend/resume protocol,
4412 // but is checked for NULL in SR_handler as a thread termination indicator.
4413 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4414 //
4415 // Note that resume_clear_context() and suspend_save_context() are needed
4416 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4417 // which in part is used by:
4418 // - Forte Analyzer: AsyncGetCallTrace()
4419 // - StackBanging: get_frame_at_stack_banging_point()
4420
4421 static void resume_clear_context(OSThread *osthread) {
4422 osthread->set_ucontext(NULL);
4423 osthread->set_siginfo(NULL);
4424 }
4425
4426 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4427 ucontext_t* context) {
4428 osthread->set_ucontext(context);
4429 osthread->set_siginfo(siginfo);
4430 }
4431
4432 // Handler function invoked when a thread's execution is suspended or
4433 // resumed. We have to be careful that only async-safe functions are
4434 // called here (Note: most pthread functions are not async safe and
4435 // should be avoided.)
4436 //
4437 // Note: sigwait() is a more natural fit than sigsuspend() from an
4438 // interface point of view, but sigwait() prevents the signal hander
4439 // from being run. libpthread would get very confused by not having
4440 // its signal handlers run and prevents sigwait()'s use with the
4441 // mutex granting granting signal.
4442 //
4443 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4444 //
4445 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4446 // Save and restore errno to avoid confusing native code with EINTR
4447 // after sigsuspend.
4448 int old_errno = errno;
4449
4450 Thread* thread = Thread::current_or_null_safe();
4451 assert(thread != NULL, "Missing current thread in SR_handler");
4452
4453 // On some systems we have seen signal delivery get "stuck" until the signal
4454 // mask is changed as part of thread termination. Check that the current thread
4455 // has not already terminated (via SR_lock()) - else the following assertion
4456 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4457 // destructor has completed.
4458
4459 if (thread->SR_lock() == NULL) {
4460 return;
4461 }
4462
4463 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4464
4465 OSThread* osthread = thread->osthread();
4466
4467 os::SuspendResume::State current = osthread->sr.state();
4468 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4469 suspend_save_context(osthread, siginfo, context);
4470
4471 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4472 os::SuspendResume::State state = osthread->sr.suspended();
4473 if (state == os::SuspendResume::SR_SUSPENDED) {
4474 sigset_t suspend_set; // signals for sigsuspend()
4475 sigemptyset(&suspend_set);
4476 // get current set of blocked signals and unblock resume signal
4477 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4478 sigdelset(&suspend_set, SR_signum);
4479
4480 sr_semaphore.signal();
4481 // wait here until we are resumed
4482 while (1) {
4483 sigsuspend(&suspend_set);
4484
4485 os::SuspendResume::State result = osthread->sr.running();
4486 if (result == os::SuspendResume::SR_RUNNING) {
4487 sr_semaphore.signal();
4488 break;
4489 }
4490 }
4491
4492 } else if (state == os::SuspendResume::SR_RUNNING) {
4493 // request was cancelled, continue
4494 } else {
4495 ShouldNotReachHere();
4496 }
4497
4498 resume_clear_context(osthread);
4499 } else if (current == os::SuspendResume::SR_RUNNING) {
4500 // request was cancelled, continue
4501 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4502 // ignore
4503 } else {
4504 // ignore
4505 }
4506
4507 errno = old_errno;
4508 }
4509
4510 static int SR_initialize() {
4511 struct sigaction act;
4512 char *s;
4513
4514 // Get signal number to use for suspend/resume
4515 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4516 int sig = ::strtol(s, 0, 10);
4517 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4518 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4519 SR_signum = sig;
4520 } else {
4521 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4522 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4523 }
4524 }
4525
4526 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4527 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4528
4529 sigemptyset(&SR_sigset);
4530 sigaddset(&SR_sigset, SR_signum);
4531
4532 // Set up signal handler for suspend/resume
4533 act.sa_flags = SA_RESTART|SA_SIGINFO;
4534 act.sa_handler = (void (*)(int)) SR_handler;
4535
4536 // SR_signum is blocked by default.
4537 // 4528190 - We also need to block pthread restart signal (32 on all
4538 // supported Linux platforms). Note that LinuxThreads need to block
4539 // this signal for all threads to work properly. So we don't have
4540 // to use hard-coded signal number when setting up the mask.
4541 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4542
4543 if (sigaction(SR_signum, &act, 0) == -1) {
4544 return -1;
4545 }
4546
4547 // Save signal flag
4548 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4549 return 0;
4550 }
4551
4552 static int sr_notify(OSThread* osthread) {
4553 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4554 assert_status(status == 0, status, "pthread_kill");
4555 return status;
4556 }
4557
4558 // "Randomly" selected value for how long we want to spin
4559 // before bailing out on suspending a thread, also how often
4560 // we send a signal to a thread we want to resume
4561 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4562 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4563
4564 // returns true on success and false on error - really an error is fatal
4565 // but this seems the normal response to library errors
4566 static bool do_suspend(OSThread* osthread) {
4567 assert(osthread->sr.is_running(), "thread should be running");
4568 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4569
4570 // mark as suspended and send signal
4571 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4572 // failed to switch, state wasn't running?
4573 ShouldNotReachHere();
4574 return false;
4575 }
4576
4577 if (sr_notify(osthread) != 0) {
4578 ShouldNotReachHere();
4579 }
4580
4581 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4582 while (true) {
4583 if (sr_semaphore.timedwait(2)) {
4584 break;
4585 } else {
4586 // timeout
4587 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4588 if (cancelled == os::SuspendResume::SR_RUNNING) {
4589 return false;
4590 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4591 // make sure that we consume the signal on the semaphore as well
4592 sr_semaphore.wait();
4593 break;
4594 } else {
4595 ShouldNotReachHere();
4596 return false;
4597 }
4598 }
4599 }
4600
4601 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4602 return true;
4603 }
4604
4605 static void do_resume(OSThread* osthread) {
4606 assert(osthread->sr.is_suspended(), "thread should be suspended");
4607 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4608
4609 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4610 // failed to switch to WAKEUP_REQUEST
4611 ShouldNotReachHere();
4612 return;
4613 }
4614
4615 while (true) {
4616 if (sr_notify(osthread) == 0) {
4617 if (sr_semaphore.timedwait(2)) {
4618 if (osthread->sr.is_running()) {
4619 return;
4620 }
4621 }
4622 } else {
4623 ShouldNotReachHere();
4624 }
4625 }
4626
4627 guarantee(osthread->sr.is_running(), "Must be running!");
4628 }
4629
4630 ///////////////////////////////////////////////////////////////////////////////////
4631 // signal handling (except suspend/resume)
4632
4633 // This routine may be used by user applications as a "hook" to catch signals.
4634 // The user-defined signal handler must pass unrecognized signals to this
4635 // routine, and if it returns true (non-zero), then the signal handler must
4636 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4637 // routine will never retun false (zero), but instead will execute a VM panic
4638 // routine kill the process.
4639 //
4640 // If this routine returns false, it is OK to call it again. This allows
4641 // the user-defined signal handler to perform checks either before or after
4642 // the VM performs its own checks. Naturally, the user code would be making
4643 // a serious error if it tried to handle an exception (such as a null check
4644 // or breakpoint) that the VM was generating for its own correct operation.
4645 //
4646 // This routine may recognize any of the following kinds of signals:
4647 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4648 // It should be consulted by handlers for any of those signals.
4649 //
4650 // The caller of this routine must pass in the three arguments supplied
4651 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4652 // field of the structure passed to sigaction(). This routine assumes that
4653 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4654 //
4655 // Note that the VM will print warnings if it detects conflicting signal
4656 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4657 //
4658 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4659 siginfo_t* siginfo,
4660 void* ucontext,
4661 int abort_if_unrecognized);
4662
4663 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4664 assert(info != NULL && uc != NULL, "it must be old kernel");
4665 int orig_errno = errno; // Preserve errno value over signal handler.
4666 JVM_handle_linux_signal(sig, info, uc, true);
4667 errno = orig_errno;
4668 }
4669
4670
4671 // This boolean allows users to forward their own non-matching signals
4672 // to JVM_handle_linux_signal, harmlessly.
4673 bool os::Linux::signal_handlers_are_installed = false;
4674
4675 // For signal-chaining
4676 bool os::Linux::libjsig_is_loaded = false;
4677 typedef struct sigaction *(*get_signal_t)(int);
4678 get_signal_t os::Linux::get_signal_action = NULL;
4679
4680 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4681 struct sigaction *actp = NULL;
4682
4683 if (libjsig_is_loaded) {
4684 // Retrieve the old signal handler from libjsig
4685 actp = (*get_signal_action)(sig);
4686 }
4687 if (actp == NULL) {
4688 // Retrieve the preinstalled signal handler from jvm
4689 actp = os::Posix::get_preinstalled_handler(sig);
4690 }
4691
4692 return actp;
4693 }
4694
4695 static bool call_chained_handler(struct sigaction *actp, int sig,
4696 siginfo_t *siginfo, void *context) {
4697 // Call the old signal handler
4698 if (actp->sa_handler == SIG_DFL) {
4699 // It's more reasonable to let jvm treat it as an unexpected exception
4700 // instead of taking the default action.
4701 return false;
4702 } else if (actp->sa_handler != SIG_IGN) {
4703 if ((actp->sa_flags & SA_NODEFER) == 0) {
4704 // automaticlly block the signal
4705 sigaddset(&(actp->sa_mask), sig);
4706 }
4707
4708 sa_handler_t hand = NULL;
4709 sa_sigaction_t sa = NULL;
4710 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4711 // retrieve the chained handler
4712 if (siginfo_flag_set) {
4713 sa = actp->sa_sigaction;
4714 } else {
4715 hand = actp->sa_handler;
4716 }
4717
4718 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4719 actp->sa_handler = SIG_DFL;
4720 }
4721
4722 // try to honor the signal mask
4723 sigset_t oset;
4724 sigemptyset(&oset);
4725 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4726
4727 // call into the chained handler
4728 if (siginfo_flag_set) {
4729 (*sa)(sig, siginfo, context);
4730 } else {
4731 (*hand)(sig);
4732 }
4733
4734 // restore the signal mask
4735 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4736 }
4737 // Tell jvm's signal handler the signal is taken care of.
4738 return true;
4739 }
4740
4741 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4742 bool chained = false;
4743 // signal-chaining
4744 if (UseSignalChaining) {
4745 struct sigaction *actp = get_chained_signal_action(sig);
4746 if (actp != NULL) {
4747 chained = call_chained_handler(actp, sig, siginfo, context);
4748 }
4749 }
4750 return chained;
4751 }
4752
4753 // for diagnostic
4754 int sigflags[NSIG];
4755
4756 int os::Linux::get_our_sigflags(int sig) {
4757 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4758 return sigflags[sig];
4759 }
4760
4761 void os::Linux::set_our_sigflags(int sig, int flags) {
4762 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4763 if (sig > 0 && sig < NSIG) {
4764 sigflags[sig] = flags;
4765 }
4766 }
4767
4768 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4769 // Check for overwrite.
4770 struct sigaction oldAct;
4771 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4772
4773 void* oldhand = oldAct.sa_sigaction
4774 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4775 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4776 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4777 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4778 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4779 if (AllowUserSignalHandlers || !set_installed) {
4780 // Do not overwrite; user takes responsibility to forward to us.
4781 return;
4782 } else if (UseSignalChaining) {
4783 // save the old handler in jvm
4784 os::Posix::save_preinstalled_handler(sig, oldAct);
4785 // libjsig also interposes the sigaction() call below and saves the
4786 // old sigaction on it own.
4787 } else {
4788 fatal("Encountered unexpected pre-existing sigaction handler "
4789 "%#lx for signal %d.", (long)oldhand, sig);
4790 }
4791 }
4792
4793 struct sigaction sigAct;
4794 sigfillset(&(sigAct.sa_mask));
4795 sigAct.sa_handler = SIG_DFL;
4796 if (!set_installed) {
4797 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4798 } else {
4799 sigAct.sa_sigaction = signalHandler;
4800 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4801 }
4802 // Save flags, which are set by ours
4803 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4804 sigflags[sig] = sigAct.sa_flags;
4805
4806 int ret = sigaction(sig, &sigAct, &oldAct);
4807 assert(ret == 0, "check");
4808
4809 void* oldhand2 = oldAct.sa_sigaction
4810 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4811 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4812 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4813 }
4814
4815 // install signal handlers for signals that HotSpot needs to
4816 // handle in order to support Java-level exception handling.
4817
4818 void os::Linux::install_signal_handlers() {
4819 if (!signal_handlers_are_installed) {
4820 signal_handlers_are_installed = true;
4821
4822 // signal-chaining
4823 typedef void (*signal_setting_t)();
4824 signal_setting_t begin_signal_setting = NULL;
4825 signal_setting_t end_signal_setting = NULL;
4826 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4827 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4828 if (begin_signal_setting != NULL) {
4829 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4830 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4831 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4832 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4833 libjsig_is_loaded = true;
4834 assert(UseSignalChaining, "should enable signal-chaining");
4835 }
4836 if (libjsig_is_loaded) {
4837 // Tell libjsig jvm is setting signal handlers
4838 (*begin_signal_setting)();
4839 }
4840
4841 set_signal_handler(SIGSEGV, true);
4842 set_signal_handler(SIGPIPE, true);
4843 set_signal_handler(SIGBUS, true);
4844 set_signal_handler(SIGILL, true);
4845 set_signal_handler(SIGFPE, true);
4846 #if defined(PPC64)
4847 set_signal_handler(SIGTRAP, true);
4848 #endif
4849 set_signal_handler(SIGXFSZ, true);
4850
4851 if (libjsig_is_loaded) {
4852 // Tell libjsig jvm finishes setting signal handlers
4853 (*end_signal_setting)();
4854 }
4855
4856 // We don't activate signal checker if libjsig is in place, we trust ourselves
4857 // and if UserSignalHandler is installed all bets are off.
4858 // Log that signal checking is off only if -verbose:jni is specified.
4859 if (CheckJNICalls) {
4860 if (libjsig_is_loaded) {
4861 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
4862 check_signals = false;
4863 }
4864 if (AllowUserSignalHandlers) {
4865 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4866 check_signals = false;
4867 }
4868 }
4869 }
4870 }
4871
4872 // This is the fastest way to get thread cpu time on Linux.
4873 // Returns cpu time (user+sys) for any thread, not only for current.
4874 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4875 // It might work on 2.6.10+ with a special kernel/glibc patch.
4876 // For reference, please, see IEEE Std 1003.1-2004:
4877 // http://www.unix.org/single_unix_specification
4878
4879 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4880 struct timespec tp;
4881 int rc = os::Posix::clock_gettime(clockid, &tp);
4882 assert(rc == 0, "clock_gettime is expected to return 0 code");
4883
4884 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4885 }
4886
4887 /////
4888 // glibc on Linux platform uses non-documented flag
4889 // to indicate, that some special sort of signal
4890 // trampoline is used.
4891 // We will never set this flag, and we should
4892 // ignore this flag in our diagnostic
4893 #ifdef SIGNIFICANT_SIGNAL_MASK
4894 #undef SIGNIFICANT_SIGNAL_MASK
4895 #endif
4896 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4897
4898 static const char* get_signal_handler_name(address handler,
4899 char* buf, int buflen) {
4900 int offset = 0;
4901 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4902 if (found) {
4903 // skip directory names
4904 const char *p1, *p2;
4905 p1 = buf;
4906 size_t len = strlen(os::file_separator());
4907 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4908 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4909 } else {
4910 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4911 }
4912 return buf;
4913 }
4914
4915 static void print_signal_handler(outputStream* st, int sig,
4916 char* buf, size_t buflen) {
4917 struct sigaction sa;
4918
4919 sigaction(sig, NULL, &sa);
4920
4921 // See comment for SIGNIFICANT_SIGNAL_MASK define
4922 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4923
4924 st->print("%s: ", os::exception_name(sig, buf, buflen));
4925
4926 address handler = (sa.sa_flags & SA_SIGINFO)
4927 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4928 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4929
4930 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4931 st->print("SIG_DFL");
4932 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4933 st->print("SIG_IGN");
4934 } else {
4935 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4936 }
4937
4938 st->print(", sa_mask[0]=");
4939 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4940
4941 address rh = VMError::get_resetted_sighandler(sig);
4942 // May be, handler was resetted by VMError?
4943 if (rh != NULL) {
4944 handler = rh;
4945 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4946 }
4947
4948 st->print(", sa_flags=");
4949 os::Posix::print_sa_flags(st, sa.sa_flags);
4950
4951 // Check: is it our handler?
4952 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4953 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4954 // It is our signal handler
4955 // check for flags, reset system-used one!
4956 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4957 st->print(
4958 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4959 os::Linux::get_our_sigflags(sig));
4960 }
4961 }
4962 st->cr();
4963 }
4964
4965
4966 #define DO_SIGNAL_CHECK(sig) \
4967 do { \
4968 if (!sigismember(&check_signal_done, sig)) { \
4969 os::Linux::check_signal_handler(sig); \
4970 } \
4971 } while (0)
4972
4973 // This method is a periodic task to check for misbehaving JNI applications
4974 // under CheckJNI, we can add any periodic checks here
4975
4976 void os::run_periodic_checks() {
4977 if (check_signals == false) return;
4978
4979 // SEGV and BUS if overridden could potentially prevent
4980 // generation of hs*.log in the event of a crash, debugging
4981 // such a case can be very challenging, so we absolutely
4982 // check the following for a good measure:
4983 DO_SIGNAL_CHECK(SIGSEGV);
4984 DO_SIGNAL_CHECK(SIGILL);
4985 DO_SIGNAL_CHECK(SIGFPE);
4986 DO_SIGNAL_CHECK(SIGBUS);
4987 DO_SIGNAL_CHECK(SIGPIPE);
4988 DO_SIGNAL_CHECK(SIGXFSZ);
4989 #if defined(PPC64)
4990 DO_SIGNAL_CHECK(SIGTRAP);
4991 #endif
4992
4993 // ReduceSignalUsage allows the user to override these handlers
4994 // see comments at the very top and jvm_md.h
4995 if (!ReduceSignalUsage) {
4996 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4997 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4998 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4999 DO_SIGNAL_CHECK(BREAK_SIGNAL);
5000 }
5001
5002 DO_SIGNAL_CHECK(SR_signum);
5003 }
5004
5005 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
5006
5007 static os_sigaction_t os_sigaction = NULL;
5008
5009 void os::Linux::check_signal_handler(int sig) {
5010 char buf[O_BUFLEN];
5011 address jvmHandler = NULL;
5012
5013
5014 struct sigaction act;
5015 if (os_sigaction == NULL) {
5016 // only trust the default sigaction, in case it has been interposed
5017 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
5018 if (os_sigaction == NULL) return;
5019 }
5020
5021 os_sigaction(sig, (struct sigaction*)NULL, &act);
5022
5023
5024 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
5025
5026 address thisHandler = (act.sa_flags & SA_SIGINFO)
5027 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
5028 : CAST_FROM_FN_PTR(address, act.sa_handler);
5029
5030
5031 switch (sig) {
5032 case SIGSEGV:
5033 case SIGBUS:
5034 case SIGFPE:
5035 case SIGPIPE:
5036 case SIGILL:
5037 case SIGXFSZ:
5038 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
5039 break;
5040
5041 case SHUTDOWN1_SIGNAL:
5042 case SHUTDOWN2_SIGNAL:
5043 case SHUTDOWN3_SIGNAL:
5044 case BREAK_SIGNAL:
5045 jvmHandler = (address)user_handler();
5046 break;
5047
5048 default:
5049 if (sig == SR_signum) {
5050 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
5051 } else {
5052 return;
5053 }
5054 break;
5055 }
5056
5057 if (thisHandler != jvmHandler) {
5058 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
5059 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
5060 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
5061 // No need to check this sig any longer
5062 sigaddset(&check_signal_done, sig);
5063 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
5064 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5065 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5066 exception_name(sig, buf, O_BUFLEN));
5067 }
5068 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5069 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5070 tty->print("expected:");
5071 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
5072 tty->cr();
5073 tty->print(" found:");
5074 os::Posix::print_sa_flags(tty, act.sa_flags);
5075 tty->cr();
5076 // No need to check this sig any longer
5077 sigaddset(&check_signal_done, sig);
5078 }
5079
5080 // Dump all the signal
5081 if (sigismember(&check_signal_done, sig)) {
5082 print_signal_handlers(tty, buf, O_BUFLEN);
5083 }
5084 }
5085
5086 extern void report_error(char* file_name, int line_no, char* title,
5087 char* format, ...);
5088
5089 // this is called _before_ most of the global arguments have been parsed
5090 void os::init(void) {
5091 char dummy; // used to get a guess on initial stack address
5092
5093 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5094
5095 init_random(1234567);
5096
5097 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5098 if (Linux::page_size() == -1) {
5099 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5100 os::strerror(errno));
5101 }
5102 init_page_sizes((size_t) Linux::page_size());
5103
5104 Linux::initialize_system_info();
5105
5106 os::Linux::CPUPerfTicks pticks;
5107 bool res = os::Linux::get_tick_information(&pticks, -1);
5108
5109 if (res && pticks.has_steal_ticks) {
5110 has_initial_tick_info = true;
5111 initial_total_ticks = pticks.total;
5112 initial_steal_ticks = pticks.steal;
5113 }
5114
5115 // _main_thread points to the thread that created/loaded the JVM.
5116 Linux::_main_thread = pthread_self();
5117
5118 // retrieve entry point for pthread_setname_np
5119 Linux::_pthread_setname_np =
5120 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5121
5122 os::Posix::init();
5123
5124 initial_time_count = javaTimeNanos();
5125
5126 // Always warn if no monotonic clock available
5127 if (!os::Posix::supports_monotonic_clock()) {
5128 warning("No monotonic clock was available - timed services may " \
5129 "be adversely affected if the time-of-day clock changes");
5130 }
5131 }
5132
5133 // To install functions for atexit system call
5134 extern "C" {
5135 static void perfMemory_exit_helper() {
5136 perfMemory_exit();
5137 }
5138 }
5139
5140 void os::pd_init_container_support() {
5141 OSContainer::init();
5142 }
5143
5144 void os::Linux::numa_init() {
5145
5146 // Java can be invoked as
5147 // 1. Without numactl and heap will be allocated/configured on all nodes as
5148 // per the system policy.
5149 // 2. With numactl --interleave:
5150 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5151 // API for membind case bitmask is reset.
5152 // Interleave is only hint and Kernel can fallback to other nodes if
5153 // no memory is available on the target nodes.
5154 // 3. With numactl --membind:
5155 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5156 // interleave case returns bitmask of all nodes.
5157 // numa_all_nodes_ptr holds bitmask of all nodes.
5158 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5159 // bitmask when externally configured to run on all or fewer nodes.
5160
5161 if (!Linux::libnuma_init()) {
5162 UseNUMA = false;
5163 } else {
5164 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5165 // If there's only one node (they start from 0) or if the process
5166 // is bound explicitly to a single node using membind, disable NUMA unless
5167 // user explicilty forces NUMA optimizations on single-node/UMA systems
5168 UseNUMA = ForceNUMA;
5169 } else {
5170
5171 LogTarget(Info,os) log;
5172 LogStream ls(log);
5173
5174 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5175
5176 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5177 const char* numa_mode = "membind";
5178
5179 if (Linux::is_running_in_interleave_mode()) {
5180 bmp = Linux::_numa_interleave_bitmask;
5181 numa_mode = "interleave";
5182 }
5183
5184 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5185 " Heap will be configured using NUMA memory nodes:", numa_mode);
5186
5187 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5188 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5189 ls.print(" %d", node);
5190 }
5191 }
5192 }
5193 }
5194
5195 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5196 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5197 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5198 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5199 // and disable adaptive resizing.
5200 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5201 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5202 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5203 UseAdaptiveSizePolicy = false;
5204 UseAdaptiveNUMAChunkSizing = false;
5205 }
5206 }
5207 }
5208
5209 // this is called _after_ the global arguments have been parsed
5210 jint os::init_2(void) {
5211
5212 // This could be set after os::Posix::init() but all platforms
5213 // have to set it the same so we have to mirror Solaris.
5214 DEBUG_ONLY(os::set_mutex_init_done();)
5215
5216 os::Posix::init_2();
5217
5218 Linux::fast_thread_clock_init();
5219
5220 // initialize suspend/resume support - must do this before signal_sets_init()
5221 if (SR_initialize() != 0) {
5222 perror("SR_initialize failed");
5223 return JNI_ERR;
5224 }
5225
5226 Linux::signal_sets_init();
5227 Linux::install_signal_handlers();
5228 // Initialize data for jdk.internal.misc.Signal
5229 if (!ReduceSignalUsage) {
5230 jdk_misc_signal_init();
5231 }
5232
5233 if (AdjustStackSizeForTLS) {
5234 get_minstack_init();
5235 }
5236
5237 // Check and sets minimum stack sizes against command line options
5238 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5239 return JNI_ERR;
5240 }
5241
5242 #if defined(IA32)
5243 // Need to ensure we've determined the process's initial stack to
5244 // perform the workaround
5245 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5246 workaround_expand_exec_shield_cs_limit();
5247 #else
5248 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5249 if (!suppress_primordial_thread_resolution) {
5250 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5251 }
5252 #endif
5253
5254 Linux::libpthread_init();
5255 Linux::sched_getcpu_init();
5256 log_info(os)("HotSpot is running with %s, %s",
5257 Linux::glibc_version(), Linux::libpthread_version());
5258
5259 if (UseNUMA) {
5260 Linux::numa_init();
5261 }
5262
5263 if (MaxFDLimit) {
5264 // set the number of file descriptors to max. print out error
5265 // if getrlimit/setrlimit fails but continue regardless.
5266 struct rlimit nbr_files;
5267 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5268 if (status != 0) {
5269 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5270 } else {
5271 nbr_files.rlim_cur = nbr_files.rlim_max;
5272 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5273 if (status != 0) {
5274 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5275 }
5276 }
5277 }
5278
5279 // at-exit methods are called in the reverse order of their registration.
5280 // atexit functions are called on return from main or as a result of a
5281 // call to exit(3C). There can be only 32 of these functions registered
5282 // and atexit() does not set errno.
5283
5284 if (PerfAllowAtExitRegistration) {
5285 // only register atexit functions if PerfAllowAtExitRegistration is set.
5286 // atexit functions can be delayed until process exit time, which
5287 // can be problematic for embedded VM situations. Embedded VMs should
5288 // call DestroyJavaVM() to assure that VM resources are released.
5289
5290 // note: perfMemory_exit_helper atexit function may be removed in
5291 // the future if the appropriate cleanup code can be added to the
5292 // VM_Exit VMOperation's doit method.
5293 if (atexit(perfMemory_exit_helper) != 0) {
5294 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5295 }
5296 }
5297
5298 // initialize thread priority policy
5299 prio_init();
5300
5301 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5302 set_coredump_filter(DAX_SHARED_BIT);
5303 }
5304
5305 if (DumpPrivateMappingsInCore) {
5306 set_coredump_filter(FILE_BACKED_PVT_BIT);
5307 }
5308
5309 if (DumpSharedMappingsInCore) {
5310 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5311 }
5312
5313 return JNI_OK;
5314 }
5315
5316 // older glibc versions don't have this macro (which expands to
5317 // an optimized bit-counting function) so we have to roll our own
5318 #ifndef CPU_COUNT
5319
5320 static int _cpu_count(const cpu_set_t* cpus) {
5321 int count = 0;
5322 // only look up to the number of configured processors
5323 for (int i = 0; i < os::processor_count(); i++) {
5324 if (CPU_ISSET(i, cpus)) {
5325 count++;
5326 }
5327 }
5328 return count;
5329 }
5330
5331 #define CPU_COUNT(cpus) _cpu_count(cpus)
5332
5333 #endif // CPU_COUNT
5334
5335 // Get the current number of available processors for this process.
5336 // This value can change at any time during a process's lifetime.
5337 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5338 // If it appears there may be more than 1024 processors then we do a
5339 // dynamic check - see 6515172 for details.
5340 // If anything goes wrong we fallback to returning the number of online
5341 // processors - which can be greater than the number available to the process.
5342 int os::Linux::active_processor_count() {
5343 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5344 cpu_set_t* cpus_p = &cpus;
5345 int cpus_size = sizeof(cpu_set_t);
5346
5347 int configured_cpus = os::processor_count(); // upper bound on available cpus
5348 int cpu_count = 0;
5349
5350 // old build platforms may not support dynamic cpu sets
5351 #ifdef CPU_ALLOC
5352
5353 // To enable easy testing of the dynamic path on different platforms we
5354 // introduce a diagnostic flag: UseCpuAllocPath
5355 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5356 // kernel may use a mask bigger than cpu_set_t
5357 log_trace(os)("active_processor_count: using dynamic path %s"
5358 "- configured processors: %d",
5359 UseCpuAllocPath ? "(forced) " : "",
5360 configured_cpus);
5361 cpus_p = CPU_ALLOC(configured_cpus);
5362 if (cpus_p != NULL) {
5363 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5364 // zero it just to be safe
5365 CPU_ZERO_S(cpus_size, cpus_p);
5366 }
5367 else {
5368 // failed to allocate so fallback to online cpus
5369 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5370 log_trace(os)("active_processor_count: "
5371 "CPU_ALLOC failed (%s) - using "
5372 "online processor count: %d",
5373 os::strerror(errno), online_cpus);
5374 return online_cpus;
5375 }
5376 }
5377 else {
5378 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5379 configured_cpus);
5380 }
5381 #else // CPU_ALLOC
5382 // these stubs won't be executed
5383 #define CPU_COUNT_S(size, cpus) -1
5384 #define CPU_FREE(cpus)
5385
5386 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5387 configured_cpus);
5388 #endif // CPU_ALLOC
5389
5390 // pid 0 means the current thread - which we have to assume represents the process
5391 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5392 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5393 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5394 }
5395 else {
5396 cpu_count = CPU_COUNT(cpus_p);
5397 }
5398 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5399 }
5400 else {
5401 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5402 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5403 "which may exceed available processors", os::strerror(errno), cpu_count);
5404 }
5405
5406 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5407 CPU_FREE(cpus_p);
5408 }
5409
5410 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5411 return cpu_count;
5412 }
5413
5414 // Determine the active processor count from one of
5415 // three different sources:
5416 //
5417 // 1. User option -XX:ActiveProcessorCount
5418 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5419 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5420 //
5421 // Option 1, if specified, will always override.
5422 // If the cgroup subsystem is active and configured, we
5423 // will return the min of the cgroup and option 2 results.
5424 // This is required since tools, such as numactl, that
5425 // alter cpu affinity do not update cgroup subsystem
5426 // cpuset configuration files.
5427 int os::active_processor_count() {
5428 // User has overridden the number of active processors
5429 if (ActiveProcessorCount > 0) {
5430 log_trace(os)("active_processor_count: "
5431 "active processor count set by user : %d",
5432 ActiveProcessorCount);
5433 return ActiveProcessorCount;
5434 }
5435
5436 int active_cpus;
5437 if (OSContainer::is_containerized()) {
5438 active_cpus = OSContainer::active_processor_count();
5439 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5440 active_cpus);
5441 } else {
5442 active_cpus = os::Linux::active_processor_count();
5443 }
5444
5445 return active_cpus;
5446 }
5447
5448 uint os::processor_id() {
5449 const int id = Linux::sched_getcpu();
5450 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5451 return (uint)id;
5452 }
5453
5454 void os::set_native_thread_name(const char *name) {
5455 if (Linux::_pthread_setname_np) {
5456 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5457 snprintf(buf, sizeof(buf), "%s", name);
5458 buf[sizeof(buf) - 1] = '\0';
5459 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5460 // ERANGE should not happen; all other errors should just be ignored.
5461 assert(rc != ERANGE, "pthread_setname_np failed");
5462 }
5463 }
5464
5465 bool os::bind_to_processor(uint processor_id) {
5466 // Not yet implemented.
5467 return false;
5468 }
5469
5470 ///
5471
5472 void os::SuspendedThreadTask::internal_do_task() {
5473 if (do_suspend(_thread->osthread())) {
5474 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5475 do_task(context);
5476 do_resume(_thread->osthread());
5477 }
5478 }
5479
5480 ////////////////////////////////////////////////////////////////////////////////
5481 // debug support
5482
5483 bool os::find(address addr, outputStream* st) {
5484 Dl_info dlinfo;
5485 memset(&dlinfo, 0, sizeof(dlinfo));
5486 if (dladdr(addr, &dlinfo) != 0) {
5487 st->print(PTR_FORMAT ": ", p2i(addr));
5488 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5489 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5490 p2i(addr) - p2i(dlinfo.dli_saddr));
5491 } else if (dlinfo.dli_fbase != NULL) {
5492 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5493 } else {
5494 st->print("<absolute address>");
5495 }
5496 if (dlinfo.dli_fname != NULL) {
5497 st->print(" in %s", dlinfo.dli_fname);
5498 }
5499 if (dlinfo.dli_fbase != NULL) {
5500 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5501 }
5502 st->cr();
5503
5504 if (Verbose) {
5505 // decode some bytes around the PC
5506 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5507 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5508 address lowest = (address) dlinfo.dli_sname;
5509 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5510 if (begin < lowest) begin = lowest;
5511 Dl_info dlinfo2;
5512 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5513 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5514 end = (address) dlinfo2.dli_saddr;
5515 }
5516 Disassembler::decode(begin, end, st);
5517 }
5518 return true;
5519 }
5520 return false;
5521 }
5522
5523 ////////////////////////////////////////////////////////////////////////////////
5524 // misc
5525
5526 // This does not do anything on Linux. This is basically a hook for being
5527 // able to use structured exception handling (thread-local exception filters)
5528 // on, e.g., Win32.
5529 void
5530 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5531 JavaCallArguments* args, Thread* thread) {
5532 f(value, method, args, thread);
5533 }
5534
5535 void os::print_statistics() {
5536 }
5537
5538 bool os::message_box(const char* title, const char* message) {
5539 int i;
5540 fdStream err(defaultStream::error_fd());
5541 for (i = 0; i < 78; i++) err.print_raw("=");
5542 err.cr();
5543 err.print_raw_cr(title);
5544 for (i = 0; i < 78; i++) err.print_raw("-");
5545 err.cr();
5546 err.print_raw_cr(message);
5547 for (i = 0; i < 78; i++) err.print_raw("=");
5548 err.cr();
5549
5550 char buf[16];
5551 // Prevent process from exiting upon "read error" without consuming all CPU
5552 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5553
5554 return buf[0] == 'y' || buf[0] == 'Y';
5555 }
5556
5557 // Is a (classpath) directory empty?
5558 bool os::dir_is_empty(const char* path) {
5559 DIR *dir = NULL;
5560 struct dirent *ptr;
5561
5562 dir = opendir(path);
5563 if (dir == NULL) return true;
5564
5565 // Scan the directory
5566 bool result = true;
5567 while (result && (ptr = readdir(dir)) != NULL) {
5568 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5569 result = false;
5570 }
5571 }
5572 closedir(dir);
5573 return result;
5574 }
5575
5576 // This code originates from JDK's sysOpen and open64_w
5577 // from src/solaris/hpi/src/system_md.c
5578
5579 int os::open(const char *path, int oflag, int mode) {
5580 if (strlen(path) > MAX_PATH - 1) {
5581 errno = ENAMETOOLONG;
5582 return -1;
5583 }
5584
5585 // All file descriptors that are opened in the Java process and not
5586 // specifically destined for a subprocess should have the close-on-exec
5587 // flag set. If we don't set it, then careless 3rd party native code
5588 // might fork and exec without closing all appropriate file descriptors
5589 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5590 // turn might:
5591 //
5592 // - cause end-of-file to fail to be detected on some file
5593 // descriptors, resulting in mysterious hangs, or
5594 //
5595 // - might cause an fopen in the subprocess to fail on a system
5596 // suffering from bug 1085341.
5597 //
5598 // (Yes, the default setting of the close-on-exec flag is a Unix
5599 // design flaw)
5600 //
5601 // See:
5602 // 1085341: 32-bit stdio routines should support file descriptors >255
5603 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5604 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5605 //
5606 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5607 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5608 // because it saves a system call and removes a small window where the flag
5609 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5610 // and we fall back to using FD_CLOEXEC (see below).
5611 #ifdef O_CLOEXEC
5612 oflag |= O_CLOEXEC;
5613 #endif
5614
5615 int fd = ::open64(path, oflag, mode);
5616 if (fd == -1) return -1;
5617
5618 //If the open succeeded, the file might still be a directory
5619 {
5620 struct stat64 buf64;
5621 int ret = ::fstat64(fd, &buf64);
5622 int st_mode = buf64.st_mode;
5623
5624 if (ret != -1) {
5625 if ((st_mode & S_IFMT) == S_IFDIR) {
5626 errno = EISDIR;
5627 ::close(fd);
5628 return -1;
5629 }
5630 } else {
5631 ::close(fd);
5632 return -1;
5633 }
5634 }
5635
5636 #ifdef FD_CLOEXEC
5637 // Validate that the use of the O_CLOEXEC flag on open above worked.
5638 // With recent kernels, we will perform this check exactly once.
5639 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5640 if (!O_CLOEXEC_is_known_to_work) {
5641 int flags = ::fcntl(fd, F_GETFD);
5642 if (flags != -1) {
5643 if ((flags & FD_CLOEXEC) != 0)
5644 O_CLOEXEC_is_known_to_work = 1;
5645 else
5646 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5647 }
5648 }
5649 #endif
5650
5651 return fd;
5652 }
5653
5654
5655 // create binary file, rewriting existing file if required
5656 int os::create_binary_file(const char* path, bool rewrite_existing) {
5657 int oflags = O_WRONLY | O_CREAT;
5658 if (!rewrite_existing) {
5659 oflags |= O_EXCL;
5660 }
5661 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5662 }
5663
5664 // return current position of file pointer
5665 jlong os::current_file_offset(int fd) {
5666 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5667 }
5668
5669 // move file pointer to the specified offset
5670 jlong os::seek_to_file_offset(int fd, jlong offset) {
5671 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5672 }
5673
5674 // This code originates from JDK's sysAvailable
5675 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5676
5677 int os::available(int fd, jlong *bytes) {
5678 jlong cur, end;
5679 int mode;
5680 struct stat64 buf64;
5681
5682 if (::fstat64(fd, &buf64) >= 0) {
5683 mode = buf64.st_mode;
5684 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5685 int n;
5686 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5687 *bytes = n;
5688 return 1;
5689 }
5690 }
5691 }
5692 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5693 return 0;
5694 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5695 return 0;
5696 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5697 return 0;
5698 }
5699 *bytes = end - cur;
5700 return 1;
5701 }
5702
5703 // Map a block of memory.
5704 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5705 char *addr, size_t bytes, bool read_only,
5706 bool allow_exec) {
5707 int prot;
5708 int flags = MAP_PRIVATE;
5709
5710 if (read_only) {
5711 prot = PROT_READ;
5712 } else {
5713 prot = PROT_READ | PROT_WRITE;
5714 }
5715
5716 if (allow_exec) {
5717 prot |= PROT_EXEC;
5718 }
5719
5720 if (addr != NULL) {
5721 flags |= MAP_FIXED;
5722 }
5723
5724 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5725 fd, file_offset);
5726 if (mapped_address == MAP_FAILED) {
5727 return NULL;
5728 }
5729 return mapped_address;
5730 }
5731
5732
5733 // Remap a block of memory.
5734 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5735 char *addr, size_t bytes, bool read_only,
5736 bool allow_exec) {
5737 // same as map_memory() on this OS
5738 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5739 allow_exec);
5740 }
5741
5742
5743 // Unmap a block of memory.
5744 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5745 return munmap(addr, bytes) == 0;
5746 }
5747
5748 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5749
5750 static jlong fast_cpu_time(Thread *thread) {
5751 clockid_t clockid;
5752 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5753 &clockid);
5754 if (rc == 0) {
5755 return os::Linux::fast_thread_cpu_time(clockid);
5756 } else {
5757 // It's possible to encounter a terminated native thread that failed
5758 // to detach itself from the VM - which should result in ESRCH.
5759 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5760 return -1;
5761 }
5762 }
5763
5764 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5765 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5766 // of a thread.
5767 //
5768 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5769 // the fast estimate available on the platform.
5770
5771 jlong os::current_thread_cpu_time() {
5772 if (os::Linux::supports_fast_thread_cpu_time()) {
5773 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5774 } else {
5775 // return user + sys since the cost is the same
5776 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5777 }
5778 }
5779
5780 jlong os::thread_cpu_time(Thread* thread) {
5781 // consistent with what current_thread_cpu_time() returns
5782 if (os::Linux::supports_fast_thread_cpu_time()) {
5783 return fast_cpu_time(thread);
5784 } else {
5785 return slow_thread_cpu_time(thread, true /* user + sys */);
5786 }
5787 }
5788
5789 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5790 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5791 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5792 } else {
5793 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5794 }
5795 }
5796
5797 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5798 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5799 return fast_cpu_time(thread);
5800 } else {
5801 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5802 }
5803 }
5804
5805 // -1 on error.
5806 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5807 pid_t tid = thread->osthread()->thread_id();
5808 char *s;
5809 char stat[2048];
5810 int statlen;
5811 char proc_name[64];
5812 int count;
5813 long sys_time, user_time;
5814 char cdummy;
5815 int idummy;
5816 long ldummy;
5817 FILE *fp;
5818
5819 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5820 fp = fopen(proc_name, "r");
5821 if (fp == NULL) return -1;
5822 statlen = fread(stat, 1, 2047, fp);
5823 stat[statlen] = '\0';
5824 fclose(fp);
5825
5826 // Skip pid and the command string. Note that we could be dealing with
5827 // weird command names, e.g. user could decide to rename java launcher
5828 // to "java 1.4.2 :)", then the stat file would look like
5829 // 1234 (java 1.4.2 :)) R ... ...
5830 // We don't really need to know the command string, just find the last
5831 // occurrence of ")" and then start parsing from there. See bug 4726580.
5832 s = strrchr(stat, ')');
5833 if (s == NULL) return -1;
5834
5835 // Skip blank chars
5836 do { s++; } while (s && isspace(*s));
5837
5838 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5839 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5840 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5841 &user_time, &sys_time);
5842 if (count != 13) return -1;
5843 if (user_sys_cpu_time) {
5844 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5845 } else {
5846 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5847 }
5848 }
5849
5850 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5851 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5852 info_ptr->may_skip_backward = false; // elapsed time not wall time
5853 info_ptr->may_skip_forward = false; // elapsed time not wall time
5854 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5855 }
5856
5857 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5858 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5859 info_ptr->may_skip_backward = false; // elapsed time not wall time
5860 info_ptr->may_skip_forward = false; // elapsed time not wall time
5861 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5862 }
5863
5864 bool os::is_thread_cpu_time_supported() {
5865 return true;
5866 }
5867
5868 // System loadavg support. Returns -1 if load average cannot be obtained.
5869 // Linux doesn't yet have a (official) notion of processor sets,
5870 // so just return the system wide load average.
5871 int os::loadavg(double loadavg[], int nelem) {
5872 return ::getloadavg(loadavg, nelem);
5873 }
5874
5875 void os::pause() {
5876 char filename[MAX_PATH];
5877 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5878 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5879 } else {
5880 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5881 }
5882
5883 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5884 if (fd != -1) {
5885 struct stat buf;
5886 ::close(fd);
5887 while (::stat(filename, &buf) == 0) {
5888 (void)::poll(NULL, 0, 100);
5889 }
5890 } else {
5891 jio_fprintf(stderr,
5892 "Could not open pause file '%s', continuing immediately.\n", filename);
5893 }
5894 }
5895
5896 extern char** environ;
5897
5898 // Run the specified command in a separate process. Return its exit value,
5899 // or -1 on failure (e.g. can't fork a new process).
5900 // Unlike system(), this function can be called from signal handler. It
5901 // doesn't block SIGINT et al.
5902 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5903 const char * argv[4] = {"sh", "-c", cmd, NULL};
5904
5905 pid_t pid ;
5906
5907 if (use_vfork_if_available) {
5908 pid = vfork();
5909 } else {
5910 pid = fork();
5911 }
5912
5913 if (pid < 0) {
5914 // fork failed
5915 return -1;
5916
5917 } else if (pid == 0) {
5918 // child process
5919
5920 execve("/bin/sh", (char* const*)argv, environ);
5921
5922 // execve failed
5923 _exit(-1);
5924
5925 } else {
5926 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5927 // care about the actual exit code, for now.
5928
5929 int status;
5930
5931 // Wait for the child process to exit. This returns immediately if
5932 // the child has already exited. */
5933 while (waitpid(pid, &status, 0) < 0) {
5934 switch (errno) {
5935 case ECHILD: return 0;
5936 case EINTR: break;
5937 default: return -1;
5938 }
5939 }
5940
5941 if (WIFEXITED(status)) {
5942 // The child exited normally; get its exit code.
5943 return WEXITSTATUS(status);
5944 } else if (WIFSIGNALED(status)) {
5945 // The child exited because of a signal
5946 // The best value to return is 0x80 + signal number,
5947 // because that is what all Unix shells do, and because
5948 // it allows callers to distinguish between process exit and
5949 // process death by signal.
5950 return 0x80 + WTERMSIG(status);
5951 } else {
5952 // Unknown exit code; pass it through
5953 return status;
5954 }
5955 }
5956 }
5957
5958 // Get the default path to the core file
5959 // Returns the length of the string
5960 int os::get_core_path(char* buffer, size_t bufferSize) {
5961 /*
5962 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5963 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5964 */
5965 const int core_pattern_len = 129;
5966 char core_pattern[core_pattern_len] = {0};
5967
5968 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5969 if (core_pattern_file == -1) {
5970 return -1;
5971 }
5972
5973 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5974 ::close(core_pattern_file);
5975 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5976 return -1;
5977 }
5978 if (core_pattern[ret-1] == '\n') {
5979 core_pattern[ret-1] = '\0';
5980 } else {
5981 core_pattern[ret] = '\0';
5982 }
5983
5984 // Replace the %p in the core pattern with the process id. NOTE: we do this
5985 // only if the pattern doesn't start with "|", and we support only one %p in
5986 // the pattern.
5987 char *pid_pos = strstr(core_pattern, "%p");
5988 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
5989 int written;
5990
5991 if (core_pattern[0] == '/') {
5992 if (pid_pos != NULL) {
5993 *pid_pos = '\0';
5994 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
5995 current_process_id(), tail);
5996 } else {
5997 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5998 }
5999 } else {
6000 char cwd[PATH_MAX];
6001
6002 const char* p = get_current_directory(cwd, PATH_MAX);
6003 if (p == NULL) {
6004 return -1;
6005 }
6006
6007 if (core_pattern[0] == '|') {
6008 written = jio_snprintf(buffer, bufferSize,
6009 "\"%s\" (or dumping to %s/core.%d)",
6010 &core_pattern[1], p, current_process_id());
6011 } else if (pid_pos != NULL) {
6012 *pid_pos = '\0';
6013 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
6014 current_process_id(), tail);
6015 } else {
6016 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6017 }
6018 }
6019
6020 if (written < 0) {
6021 return -1;
6022 }
6023
6024 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6025 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6026
6027 if (core_uses_pid_file != -1) {
6028 char core_uses_pid = 0;
6029 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6030 ::close(core_uses_pid_file);
6031
6032 if (core_uses_pid == '1') {
6033 jio_snprintf(buffer + written, bufferSize - written,
6034 ".%d", current_process_id());
6035 }
6036 }
6037 }
6038
6039 return strlen(buffer);
6040 }
6041
6042 bool os::start_debugging(char *buf, int buflen) {
6043 int len = (int)strlen(buf);
6044 char *p = &buf[len];
6045
6046 jio_snprintf(p, buflen-len,
6047 "\n\n"
6048 "Do you want to debug the problem?\n\n"
6049 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6050 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6051 "Otherwise, press RETURN to abort...",
6052 os::current_process_id(), os::current_process_id(),
6053 os::current_thread_id(), os::current_thread_id());
6054
6055 bool yes = os::message_box("Unexpected Error", buf);
6056
6057 if (yes) {
6058 // yes, user asked VM to launch debugger
6059 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6060 os::current_process_id(), os::current_process_id());
6061
6062 os::fork_and_exec(buf);
6063 yes = false;
6064 }
6065 return yes;
6066 }
6067
6068
6069 // Java/Compiler thread:
6070 //
6071 // Low memory addresses
6072 // P0 +------------------------+
6073 // | |\ Java thread created by VM does not have glibc
6074 // | glibc guard page | - guard page, attached Java thread usually has
6075 // | |/ 1 glibc guard page.
6076 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6077 // | |\
6078 // | HotSpot Guard Pages | - red, yellow and reserved pages
6079 // | |/
6080 // +------------------------+ JavaThread::stack_reserved_zone_base()
6081 // | |\
6082 // | Normal Stack | -
6083 // | |/
6084 // P2 +------------------------+ Thread::stack_base()
6085 //
6086 // Non-Java thread:
6087 //
6088 // Low memory addresses
6089 // P0 +------------------------+
6090 // | |\
6091 // | glibc guard page | - usually 1 page
6092 // | |/
6093 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6094 // | |\
6095 // | Normal Stack | -
6096 // | |/
6097 // P2 +------------------------+ Thread::stack_base()
6098 //
6099 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6100 // returned from pthread_attr_getstack().
6101 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6102 // of the stack size given in pthread_attr. We work around this for
6103 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6104 //
6105 #ifndef ZERO
6106 static void current_stack_region(address * bottom, size_t * size) {
6107 if (os::is_primordial_thread()) {
6108 // primordial thread needs special handling because pthread_getattr_np()
6109 // may return bogus value.
6110 *bottom = os::Linux::initial_thread_stack_bottom();
6111 *size = os::Linux::initial_thread_stack_size();
6112 } else {
6113 pthread_attr_t attr;
6114
6115 int rslt = pthread_getattr_np(pthread_self(), &attr);
6116
6117 // JVM needs to know exact stack location, abort if it fails
6118 if (rslt != 0) {
6119 if (rslt == ENOMEM) {
6120 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6121 } else {
6122 fatal("pthread_getattr_np failed with error = %d", rslt);
6123 }
6124 }
6125
6126 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6127 fatal("Cannot locate current stack attributes!");
6128 }
6129
6130 // Work around NPTL stack guard error.
6131 size_t guard_size = 0;
6132 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6133 if (rslt != 0) {
6134 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6135 }
6136 *bottom += guard_size;
6137 *size -= guard_size;
6138
6139 pthread_attr_destroy(&attr);
6140
6141 }
6142 assert(os::current_stack_pointer() >= *bottom &&
6143 os::current_stack_pointer() < *bottom + *size, "just checking");
6144 }
6145
6146 address os::current_stack_base() {
6147 address bottom;
6148 size_t size;
6149 current_stack_region(&bottom, &size);
6150 return (bottom + size);
6151 }
6152
6153 size_t os::current_stack_size() {
6154 // This stack size includes the usable stack and HotSpot guard pages
6155 // (for the threads that have Hotspot guard pages).
6156 address bottom;
6157 size_t size;
6158 current_stack_region(&bottom, &size);
6159 return size;
6160 }
6161 #endif
6162
6163 static inline struct timespec get_mtime(const char* filename) {
6164 struct stat st;
6165 int ret = os::stat(filename, &st);
6166 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6167 return st.st_mtim;
6168 }
6169
6170 int os::compare_file_modified_times(const char* file1, const char* file2) {
6171 struct timespec filetime1 = get_mtime(file1);
6172 struct timespec filetime2 = get_mtime(file2);
6173 int diff = filetime1.tv_sec - filetime2.tv_sec;
6174 if (diff == 0) {
6175 return filetime1.tv_nsec - filetime2.tv_nsec;
6176 }
6177 return diff;
6178 }
6179
6180 bool os::supports_map_sync() {
6181 return true;
6182 }
6183
6184 /////////////// Unit tests ///////////////
6185
6186 #ifndef PRODUCT
6187
6188 class TestReserveMemorySpecial : AllStatic {
6189 public:
6190 static void small_page_write(void* addr, size_t size) {
6191 size_t page_size = os::vm_page_size();
6192
6193 char* end = (char*)addr + size;
6194 for (char* p = (char*)addr; p < end; p += page_size) {
6195 *p = 1;
6196 }
6197 }
6198
6199 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6200 if (!UseHugeTLBFS) {
6201 return;
6202 }
6203
6204 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6205
6206 if (addr != NULL) {
6207 small_page_write(addr, size);
6208
6209 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6210 }
6211 }
6212
6213 static void test_reserve_memory_special_huge_tlbfs_only() {
6214 if (!UseHugeTLBFS) {
6215 return;
6216 }
6217
6218 size_t lp = os::large_page_size();
6219
6220 for (size_t size = lp; size <= lp * 10; size += lp) {
6221 test_reserve_memory_special_huge_tlbfs_only(size);
6222 }
6223 }
6224
6225 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6226 size_t lp = os::large_page_size();
6227 size_t ag = os::vm_allocation_granularity();
6228
6229 // sizes to test
6230 const size_t sizes[] = {
6231 lp, lp + ag, lp + lp / 2, lp * 2,
6232 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6233 lp * 10, lp * 10 + lp / 2
6234 };
6235 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6236
6237 // For each size/alignment combination, we test three scenarios:
6238 // 1) with req_addr == NULL
6239 // 2) with a non-null req_addr at which we expect to successfully allocate
6240 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6241 // expect the allocation to either fail or to ignore req_addr
6242
6243 // Pre-allocate two areas; they shall be as large as the largest allocation
6244 // and aligned to the largest alignment we will be testing.
6245 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6246 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6247 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6248 -1, 0);
6249 assert(mapping1 != MAP_FAILED, "should work");
6250
6251 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6252 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6253 -1, 0);
6254 assert(mapping2 != MAP_FAILED, "should work");
6255
6256 // Unmap the first mapping, but leave the second mapping intact: the first
6257 // mapping will serve as a value for a "good" req_addr (case 2). The second
6258 // mapping, still intact, as "bad" req_addr (case 3).
6259 ::munmap(mapping1, mapping_size);
6260
6261 // Case 1
6262 for (int i = 0; i < num_sizes; i++) {
6263 const size_t size = sizes[i];
6264 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6265 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6266 if (p != NULL) {
6267 assert(is_aligned(p, alignment), "must be");
6268 small_page_write(p, size);
6269 os::Linux::release_memory_special_huge_tlbfs(p, size);
6270 }
6271 }
6272 }
6273
6274 // Case 2
6275 for (int i = 0; i < num_sizes; i++) {
6276 const size_t size = sizes[i];
6277 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6278 char* const req_addr = align_up(mapping1, alignment);
6279 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6280 if (p != NULL) {
6281 assert(p == req_addr, "must be");
6282 small_page_write(p, size);
6283 os::Linux::release_memory_special_huge_tlbfs(p, size);
6284 }
6285 }
6286 }
6287
6288 // Case 3
6289 for (int i = 0; i < num_sizes; i++) {
6290 const size_t size = sizes[i];
6291 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6292 char* const req_addr = align_up(mapping2, alignment);
6293 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6294 // as the area around req_addr contains already existing mappings, the API should always
6295 // return NULL (as per contract, it cannot return another address)
6296 assert(p == NULL, "must be");
6297 }
6298 }
6299
6300 ::munmap(mapping2, mapping_size);
6301
6302 }
6303
6304 static void test_reserve_memory_special_huge_tlbfs() {
6305 if (!UseHugeTLBFS) {
6306 return;
6307 }
6308
6309 test_reserve_memory_special_huge_tlbfs_only();
6310 test_reserve_memory_special_huge_tlbfs_mixed();
6311 }
6312
6313 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6314 if (!UseSHM) {
6315 return;
6316 }
6317
6318 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6319
6320 if (addr != NULL) {
6321 assert(is_aligned(addr, alignment), "Check");
6322 assert(is_aligned(addr, os::large_page_size()), "Check");
6323
6324 small_page_write(addr, size);
6325
6326 os::Linux::release_memory_special_shm(addr, size);
6327 }
6328 }
6329
6330 static void test_reserve_memory_special_shm() {
6331 size_t lp = os::large_page_size();
6332 size_t ag = os::vm_allocation_granularity();
6333
6334 for (size_t size = ag; size < lp * 3; size += ag) {
6335 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6336 test_reserve_memory_special_shm(size, alignment);
6337 }
6338 }
6339 }
6340
6341 static void test() {
6342 test_reserve_memory_special_huge_tlbfs();
6343 test_reserve_memory_special_shm();
6344 }
6345 };
6346
6347 void TestReserveMemorySpecial_test() {
6348 TestReserveMemorySpecial::test();
6349 }
6350
6351 #endif