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 size_t os::Linux::_default_large_page_size = 0;
158
159 static jlong initial_time_count=0;
160
161 static int clock_tics_per_sec = 100;
162
163 // If the VM might have been created on the primordial thread, we need to resolve the
164 // primordial thread stack bounds and check if the current thread might be the
165 // primordial thread in places. If we know that the primordial thread is never used,
166 // such as when the VM was created by one of the standard java launchers, we can
167 // avoid this
168 static bool suppress_primordial_thread_resolution = false;
169
170 // For diagnostics to print a message once. see run_periodic_checks
171 static sigset_t check_signal_done;
172 static bool check_signals = true;
173
174 // Signal number used to suspend/resume a thread
175
176 // do not use any signal number less than SIGSEGV, see 4355769
177 static int SR_signum = SIGUSR2;
178 sigset_t SR_sigset;
179
180 // utility functions
181
182 static int SR_initialize();
183
184 julong os::available_memory() {
185 return Linux::available_memory();
186 }
187
188 julong os::Linux::available_memory() {
189 // values in struct sysinfo are "unsigned long"
190 struct sysinfo si;
191 julong avail_mem;
192
193 if (OSContainer::is_containerized()) {
194 jlong mem_limit, mem_usage;
195 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
196 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
197 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
198 }
199 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
200 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
201 }
202 if (mem_limit > 0 && mem_usage > 0 ) {
203 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
204 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
205 return avail_mem;
206 }
207 }
208
209 sysinfo(&si);
210 avail_mem = (julong)si.freeram * si.mem_unit;
211 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
212 return avail_mem;
213 }
214
215 julong os::physical_memory() {
216 jlong phys_mem = 0;
217 if (OSContainer::is_containerized()) {
218 jlong mem_limit;
219 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
220 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
221 return mem_limit;
222 }
223 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
224 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
225 }
226
227 phys_mem = Linux::physical_memory();
228 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
229 return phys_mem;
230 }
231
232 static uint64_t initial_total_ticks = 0;
233 static uint64_t initial_steal_ticks = 0;
234 static bool has_initial_tick_info = false;
235
236 static void next_line(FILE *f) {
237 int c;
238 do {
239 c = fgetc(f);
240 } while (c != '\n' && c != EOF);
241 }
242
243 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
244 FILE* fh;
245 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
246 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
247 // irq: time servicing interrupts; softirq: time servicing softirqs
248 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
249 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
250 uint64_t stealTicks = 0;
251 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
252 // control of the Linux kernel
253 uint64_t guestNiceTicks = 0;
254 int logical_cpu = -1;
255 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
256 int n;
257
258 memset(pticks, 0, sizeof(CPUPerfTicks));
259
260 if ((fh = fopen("/proc/stat", "r")) == NULL) {
261 return false;
262 }
263
264 if (which_logical_cpu == -1) {
265 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
266 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
267 UINT64_FORMAT " " UINT64_FORMAT " ",
268 &userTicks, &niceTicks, &systemTicks, &idleTicks,
269 &iowTicks, &irqTicks, &sirqTicks,
270 &stealTicks, &guestNiceTicks);
271 } else {
272 // Move to next line
273 next_line(fh);
274
275 // find the line for requested cpu faster to just iterate linefeeds?
276 for (int i = 0; i < which_logical_cpu; i++) {
277 next_line(fh);
278 }
279
280 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
281 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
282 UINT64_FORMAT " " UINT64_FORMAT " ",
283 &logical_cpu, &userTicks, &niceTicks,
284 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
285 &stealTicks, &guestNiceTicks);
286 }
287
288 fclose(fh);
289 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
290 return false;
291 }
292 pticks->used = userTicks + niceTicks;
293 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
294 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
295 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
296
297 if (n > required_tickinfo_count + 3) {
298 pticks->steal = stealTicks;
299 pticks->has_steal_ticks = true;
300 } else {
301 pticks->steal = 0;
302 pticks->has_steal_ticks = false;
303 }
304
305 return true;
306 }
307
308 // Return true if user is running as root.
309
310 bool os::have_special_privileges() {
311 static bool init = false;
312 static bool privileges = false;
313 if (!init) {
314 privileges = (getuid() != geteuid()) || (getgid() != getegid());
315 init = true;
316 }
317 return privileges;
318 }
319
320
321 #ifndef SYS_gettid
322 // i386: 224, ia64: 1105, amd64: 186, sparc 143
323 #ifdef __ia64__
324 #define SYS_gettid 1105
325 #else
326 #ifdef __i386__
327 #define SYS_gettid 224
328 #else
329 #ifdef __amd64__
330 #define SYS_gettid 186
331 #else
332 #ifdef __sparc__
333 #define SYS_gettid 143
334 #else
335 #error define gettid for the arch
336 #endif
337 #endif
338 #endif
339 #endif
340 #endif
341
342
343 // pid_t gettid()
344 //
345 // Returns the kernel thread id of the currently running thread. Kernel
346 // thread id is used to access /proc.
347 pid_t os::Linux::gettid() {
348 int rslt = syscall(SYS_gettid);
349 assert(rslt != -1, "must be."); // old linuxthreads implementation?
350 return (pid_t)rslt;
351 }
352
353 // Most versions of linux have a bug where the number of processors are
354 // determined by looking at the /proc file system. In a chroot environment,
355 // the system call returns 1.
356 static bool unsafe_chroot_detected = false;
357 static const char *unstable_chroot_error = "/proc file system not found.\n"
358 "Java may be unstable running multithreaded in a chroot "
359 "environment on Linux when /proc filesystem is not mounted.";
360
361 void os::Linux::initialize_system_info() {
362 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
363 if (processor_count() == 1) {
364 pid_t pid = os::Linux::gettid();
365 char fname[32];
366 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
367 FILE *fp = fopen(fname, "r");
368 if (fp == NULL) {
369 unsafe_chroot_detected = true;
370 } else {
371 fclose(fp);
372 }
373 }
374 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
375 assert(processor_count() > 0, "linux error");
376 }
377
378 void os::init_system_properties_values() {
379 // The next steps are taken in the product version:
380 //
381 // Obtain the JAVA_HOME value from the location of libjvm.so.
382 // This library should be located at:
383 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
384 //
385 // If "/jre/lib/" appears at the right place in the path, then we
386 // assume libjvm.so is installed in a JDK and we use this path.
387 //
388 // Otherwise exit with message: "Could not create the Java virtual machine."
389 //
390 // The following extra steps are taken in the debugging version:
391 //
392 // If "/jre/lib/" does NOT appear at the right place in the path
393 // instead of exit check for $JAVA_HOME environment variable.
394 //
395 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
396 // then we append a fake suffix "hotspot/libjvm.so" to this path so
397 // it looks like libjvm.so is installed there
398 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
399 //
400 // Otherwise exit.
401 //
402 // Important note: if the location of libjvm.so changes this
403 // code needs to be changed accordingly.
404
405 // See ld(1):
406 // The linker uses the following search paths to locate required
407 // shared libraries:
408 // 1: ...
409 // ...
410 // 7: The default directories, normally /lib and /usr/lib.
411 #ifndef OVERRIDE_LIBPATH
412 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
413 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
414 #else
415 #define DEFAULT_LIBPATH "/lib:/usr/lib"
416 #endif
417 #else
418 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
419 #endif
420
421 // Base path of extensions installed on the system.
422 #define SYS_EXT_DIR "/usr/java/packages"
423 #define EXTENSIONS_DIR "/lib/ext"
424
425 // Buffer that fits several sprintfs.
426 // Note that the space for the colon and the trailing null are provided
427 // by the nulls included by the sizeof operator.
428 const size_t bufsize =
429 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
430 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
431 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
432
433 // sysclasspath, java_home, dll_dir
434 {
435 char *pslash;
436 os::jvm_path(buf, bufsize);
437
438 // Found the full path to libjvm.so.
439 // Now cut the path to <java_home>/jre if we can.
440 pslash = strrchr(buf, '/');
441 if (pslash != NULL) {
442 *pslash = '\0'; // Get rid of /libjvm.so.
443 }
444 pslash = strrchr(buf, '/');
445 if (pslash != NULL) {
446 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
447 }
448 Arguments::set_dll_dir(buf);
449
450 if (pslash != NULL) {
451 pslash = strrchr(buf, '/');
452 if (pslash != NULL) {
453 *pslash = '\0'; // Get rid of /lib.
454 }
455 }
456 Arguments::set_java_home(buf);
457 if (!set_boot_path('/', ':')) {
458 vm_exit_during_initialization("Failed setting boot class path.", NULL);
459 }
460 }
461
462 // Where to look for native libraries.
463 //
464 // Note: Due to a legacy implementation, most of the library path
465 // is set in the launcher. This was to accomodate linking restrictions
466 // on legacy Linux implementations (which are no longer supported).
467 // Eventually, all the library path setting will be done here.
468 //
469 // However, to prevent the proliferation of improperly built native
470 // libraries, the new path component /usr/java/packages is added here.
471 // Eventually, all the library path setting will be done here.
472 {
473 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
474 // should always exist (until the legacy problem cited above is
475 // addressed).
476 const char *v = ::getenv("LD_LIBRARY_PATH");
477 const char *v_colon = ":";
478 if (v == NULL) { v = ""; v_colon = ""; }
479 // That's +1 for the colon and +1 for the trailing '\0'.
480 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
481 strlen(v) + 1 +
482 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
483 mtInternal);
484 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
485 Arguments::set_library_path(ld_library_path);
486 FREE_C_HEAP_ARRAY(char, ld_library_path);
487 }
488
489 // Extensions directories.
490 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
491 Arguments::set_ext_dirs(buf);
492
493 FREE_C_HEAP_ARRAY(char, buf);
494
495 #undef DEFAULT_LIBPATH
496 #undef SYS_EXT_DIR
497 #undef EXTENSIONS_DIR
498 }
499
500 ////////////////////////////////////////////////////////////////////////////////
501 // breakpoint support
502
503 void os::breakpoint() {
504 BREAKPOINT;
505 }
506
507 extern "C" void breakpoint() {
508 // use debugger to set breakpoint here
509 }
510
511 ////////////////////////////////////////////////////////////////////////////////
512 // signal support
513
514 debug_only(static bool signal_sets_initialized = false);
515 static sigset_t unblocked_sigs, vm_sigs;
516
517 void os::Linux::signal_sets_init() {
518 // Should also have an assertion stating we are still single-threaded.
519 assert(!signal_sets_initialized, "Already initialized");
520 // Fill in signals that are necessarily unblocked for all threads in
521 // the VM. Currently, we unblock the following signals:
522 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
523 // by -Xrs (=ReduceSignalUsage));
524 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
525 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
526 // the dispositions or masks wrt these signals.
527 // Programs embedding the VM that want to use the above signals for their
528 // own purposes must, at this time, use the "-Xrs" option to prevent
529 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
530 // (See bug 4345157, and other related bugs).
531 // In reality, though, unblocking these signals is really a nop, since
532 // these signals are not blocked by default.
533 sigemptyset(&unblocked_sigs);
534 sigaddset(&unblocked_sigs, SIGILL);
535 sigaddset(&unblocked_sigs, SIGSEGV);
536 sigaddset(&unblocked_sigs, SIGBUS);
537 sigaddset(&unblocked_sigs, SIGFPE);
538 #if defined(PPC64)
539 sigaddset(&unblocked_sigs, SIGTRAP);
540 #endif
541 sigaddset(&unblocked_sigs, SR_signum);
542
543 if (!ReduceSignalUsage) {
544 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
545 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
546 }
547 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
548 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
549 }
550 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
551 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
552 }
553 }
554 // Fill in signals that are blocked by all but the VM thread.
555 sigemptyset(&vm_sigs);
556 if (!ReduceSignalUsage) {
557 sigaddset(&vm_sigs, BREAK_SIGNAL);
558 }
559 debug_only(signal_sets_initialized = true);
560
561 }
562
563 // These are signals that are unblocked while a thread is running Java.
564 // (For some reason, they get blocked by default.)
565 sigset_t* os::Linux::unblocked_signals() {
566 assert(signal_sets_initialized, "Not initialized");
567 return &unblocked_sigs;
568 }
569
570 // These are the signals that are blocked while a (non-VM) thread is
571 // running Java. Only the VM thread handles these signals.
572 sigset_t* os::Linux::vm_signals() {
573 assert(signal_sets_initialized, "Not initialized");
574 return &vm_sigs;
575 }
576
577 void os::Linux::hotspot_sigmask(Thread* thread) {
578
579 //Save caller's signal mask before setting VM signal mask
580 sigset_t caller_sigmask;
581 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
582
583 OSThread* osthread = thread->osthread();
584 osthread->set_caller_sigmask(caller_sigmask);
585
586 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
587
588 if (!ReduceSignalUsage) {
589 if (thread->is_VM_thread()) {
590 // Only the VM thread handles BREAK_SIGNAL ...
591 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
592 } else {
593 // ... all other threads block BREAK_SIGNAL
594 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
595 }
596 }
597 }
598
599 //////////////////////////////////////////////////////////////////////////////
600 // detecting pthread library
601
602 void os::Linux::libpthread_init() {
603 // Save glibc and pthread version strings.
604 #if !defined(_CS_GNU_LIBC_VERSION) || \
605 !defined(_CS_GNU_LIBPTHREAD_VERSION)
606 #error "glibc too old (< 2.3.2)"
607 #endif
608
609 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
610 assert(n > 0, "cannot retrieve glibc version");
611 char *str = (char *)malloc(n, mtInternal);
612 confstr(_CS_GNU_LIBC_VERSION, str, n);
613 os::Linux::set_glibc_version(str);
614
615 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
616 assert(n > 0, "cannot retrieve pthread version");
617 str = (char *)malloc(n, mtInternal);
618 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
619 os::Linux::set_libpthread_version(str);
620 }
621
622 /////////////////////////////////////////////////////////////////////////////
623 // thread stack expansion
624
625 // os::Linux::manually_expand_stack() takes care of expanding the thread
626 // stack. Note that this is normally not needed: pthread stacks allocate
627 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
628 // committed. Therefore it is not necessary to expand the stack manually.
629 //
630 // Manually expanding the stack was historically needed on LinuxThreads
631 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
632 // it is kept to deal with very rare corner cases:
633 //
634 // For one, user may run the VM on an own implementation of threads
635 // whose stacks are - like the old LinuxThreads - implemented using
636 // mmap(MAP_GROWSDOWN).
637 //
638 // Also, this coding may be needed if the VM is running on the primordial
639 // thread. Normally we avoid running on the primordial thread; however,
640 // user may still invoke the VM on the primordial thread.
641 //
642 // The following historical comment describes the details about running
643 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
644
645
646 // Force Linux kernel to expand current thread stack. If "bottom" is close
647 // to the stack guard, caller should block all signals.
648 //
649 // MAP_GROWSDOWN:
650 // A special mmap() flag that is used to implement thread stacks. It tells
651 // kernel that the memory region should extend downwards when needed. This
652 // allows early versions of LinuxThreads to only mmap the first few pages
653 // when creating a new thread. Linux kernel will automatically expand thread
654 // stack as needed (on page faults).
655 //
656 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
657 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
658 // region, it's hard to tell if the fault is due to a legitimate stack
659 // access or because of reading/writing non-exist memory (e.g. buffer
660 // overrun). As a rule, if the fault happens below current stack pointer,
661 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
662 // application (see Linux kernel fault.c).
663 //
664 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
665 // stack overflow detection.
666 //
667 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
668 // not use MAP_GROWSDOWN.
669 //
670 // To get around the problem and allow stack banging on Linux, we need to
671 // manually expand thread stack after receiving the SIGSEGV.
672 //
673 // There are two ways to expand thread stack to address "bottom", we used
674 // both of them in JVM before 1.5:
675 // 1. adjust stack pointer first so that it is below "bottom", and then
676 // touch "bottom"
677 // 2. mmap() the page in question
678 //
679 // Now alternate signal stack is gone, it's harder to use 2. For instance,
680 // if current sp is already near the lower end of page 101, and we need to
681 // call mmap() to map page 100, it is possible that part of the mmap() frame
682 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
683 // That will destroy the mmap() frame and cause VM to crash.
684 //
685 // The following code works by adjusting sp first, then accessing the "bottom"
686 // page to force a page fault. Linux kernel will then automatically expand the
687 // stack mapping.
688 //
689 // _expand_stack_to() assumes its frame size is less than page size, which
690 // should always be true if the function is not inlined.
691
692 static void NOINLINE _expand_stack_to(address bottom) {
693 address sp;
694 size_t size;
695 volatile char *p;
696
697 // Adjust bottom to point to the largest address within the same page, it
698 // gives us a one-page buffer if alloca() allocates slightly more memory.
699 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
700 bottom += os::Linux::page_size() - 1;
701
702 // sp might be slightly above current stack pointer; if that's the case, we
703 // will alloca() a little more space than necessary, which is OK. Don't use
704 // os::current_stack_pointer(), as its result can be slightly below current
705 // stack pointer, causing us to not alloca enough to reach "bottom".
706 sp = (address)&sp;
707
708 if (sp > bottom) {
709 size = sp - bottom;
710 p = (volatile char *)alloca(size);
711 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
712 p[0] = '\0';
713 }
714 }
715
716 void os::Linux::expand_stack_to(address bottom) {
717 _expand_stack_to(bottom);
718 }
719
720 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
721 assert(t!=NULL, "just checking");
722 assert(t->osthread()->expanding_stack(), "expand should be set");
723
724 if (t->is_in_usable_stack(addr)) {
725 sigset_t mask_all, old_sigset;
726 sigfillset(&mask_all);
727 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
728 _expand_stack_to(addr);
729 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
730 return true;
731 }
732 return false;
733 }
734
735 //////////////////////////////////////////////////////////////////////////////
736 // create new thread
737
738 // Thread start routine for all newly created threads
739 static void *thread_native_entry(Thread *thread) {
740
741 thread->record_stack_base_and_size();
742
743 // Try to randomize the cache line index of hot stack frames.
744 // This helps when threads of the same stack traces evict each other's
745 // cache lines. The threads can be either from the same JVM instance, or
746 // from different JVM instances. The benefit is especially true for
747 // processors with hyperthreading technology.
748 static int counter = 0;
749 int pid = os::current_process_id();
750 alloca(((pid ^ counter++) & 7) * 128);
751
752 thread->initialize_thread_current();
753
754 OSThread* osthread = thread->osthread();
755 Monitor* sync = osthread->startThread_lock();
756
757 osthread->set_thread_id(os::current_thread_id());
758
759 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
760 os::current_thread_id(), (uintx) pthread_self());
761
762 if (UseNUMA) {
763 int lgrp_id = os::numa_get_group_id();
764 if (lgrp_id != -1) {
765 thread->set_lgrp_id(lgrp_id);
766 }
767 }
768 // initialize signal mask for this thread
769 os::Linux::hotspot_sigmask(thread);
770
771 // initialize floating point control register
772 os::Linux::init_thread_fpu_state();
773
774 // handshaking with parent thread
775 {
776 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
777
778 // notify parent thread
779 osthread->set_state(INITIALIZED);
780 sync->notify_all();
781
782 // wait until os::start_thread()
783 while (osthread->get_state() == INITIALIZED) {
784 sync->wait_without_safepoint_check();
785 }
786 }
787
788 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
789
790 // call one more level start routine
791 thread->call_run();
792
793 // Note: at this point the thread object may already have deleted itself.
794 // Prevent dereferencing it from here on out.
795 thread = NULL;
796
797 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
798 os::current_thread_id(), (uintx) pthread_self());
799
800 return 0;
801 }
802
803 // On Linux, glibc places static TLS blocks (for __thread variables) on
804 // the thread stack. This decreases the stack size actually available
805 // to threads.
806 //
807 // For large static TLS sizes, this may cause threads to malfunction due
808 // to insufficient stack space. This is a well-known issue in glibc:
809 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
810 //
811 // As a workaround, we call a private but assumed-stable glibc function,
812 // __pthread_get_minstack() to obtain the minstack size and derive the
813 // static TLS size from it. We then increase the user requested stack
814 // size by this TLS size.
815 //
816 // Due to compatibility concerns, this size adjustment is opt-in and
817 // controlled via AdjustStackSizeForTLS.
818 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
819
820 GetMinStack _get_minstack_func = NULL;
821
822 static void get_minstack_init() {
823 _get_minstack_func =
824 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
825 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
826 _get_minstack_func == NULL ? "failed" : "succeeded");
827 }
828
829 // Returns the size of the static TLS area glibc puts on thread stacks.
830 // The value is cached on first use, which occurs when the first thread
831 // is created during VM initialization.
832 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
833 size_t tls_size = 0;
834 if (_get_minstack_func != NULL) {
835 // Obtain the pthread minstack size by calling __pthread_get_minstack.
836 size_t minstack_size = _get_minstack_func(attr);
837
838 // Remove non-TLS area size included in minstack size returned
839 // by __pthread_get_minstack() to get the static TLS size.
840 // In glibc before 2.27, minstack size includes guard_size.
841 // In glibc 2.27 and later, guard_size is automatically added
842 // to the stack size by pthread_create and is no longer included
843 // in minstack size. In both cases, the guard_size is taken into
844 // account, so there is no need to adjust the result for that.
845 //
846 // Although __pthread_get_minstack() is a private glibc function,
847 // it is expected to have a stable behavior across future glibc
848 // versions while glibc still allocates the static TLS blocks off
849 // the stack. Following is glibc 2.28 __pthread_get_minstack():
850 //
851 // size_t
852 // __pthread_get_minstack (const pthread_attr_t *attr)
853 // {
854 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
855 // }
856 //
857 //
858 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
859 // if check is done for precaution.
860 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
861 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
862 }
863 }
864
865 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
866 tls_size);
867 return tls_size;
868 }
869
870 bool os::create_thread(Thread* thread, ThreadType thr_type,
871 size_t req_stack_size) {
872 assert(thread->osthread() == NULL, "caller responsible");
873
874 // Allocate the OSThread object
875 OSThread* osthread = new OSThread(NULL, NULL);
876 if (osthread == NULL) {
877 return false;
878 }
879
880 // set the correct thread state
881 osthread->set_thread_type(thr_type);
882
883 // Initial state is ALLOCATED but not INITIALIZED
884 osthread->set_state(ALLOCATED);
885
886 thread->set_osthread(osthread);
887
888 // init thread attributes
889 pthread_attr_t attr;
890 pthread_attr_init(&attr);
891 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
892
893 // Calculate stack size if it's not specified by caller.
894 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
895 // In glibc versions prior to 2.7 the guard size mechanism
896 // is not implemented properly. The posix standard requires adding
897 // the size of the guard pages to the stack size, instead Linux
898 // takes the space out of 'stacksize'. Thus we adapt the requested
899 // stack_size by the size of the guard pages to mimick proper
900 // behaviour. However, be careful not to end up with a size
901 // of zero due to overflow. Don't add the guard page in that case.
902 size_t guard_size = os::Linux::default_guard_size(thr_type);
903 // Configure glibc guard page. Must happen before calling
904 // get_static_tls_area_size(), which uses the guard_size.
905 pthread_attr_setguardsize(&attr, guard_size);
906
907 size_t stack_adjust_size = 0;
908 if (AdjustStackSizeForTLS) {
909 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
910 stack_adjust_size += get_static_tls_area_size(&attr);
911 } else {
912 stack_adjust_size += guard_size;
913 }
914
915 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
916 if (stack_size <= SIZE_MAX - stack_adjust_size) {
917 stack_size += stack_adjust_size;
918 }
919 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
920
921 int status = pthread_attr_setstacksize(&attr, stack_size);
922 assert_status(status == 0, status, "pthread_attr_setstacksize");
923
924 ThreadState state;
925
926 {
927 pthread_t tid;
928 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
929
930 char buf[64];
931 if (ret == 0) {
932 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
933 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
934 } else {
935 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
936 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
937 // Log some OS information which might explain why creating the thread failed.
938 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
939 LogStream st(Log(os, thread)::info());
940 os::Posix::print_rlimit_info(&st);
941 os::print_memory_info(&st);
942 os::Linux::print_proc_sys_info(&st);
943 os::Linux::print_container_info(&st);
944 }
945
946 pthread_attr_destroy(&attr);
947
948 if (ret != 0) {
949 // Need to clean up stuff we've allocated so far
950 thread->set_osthread(NULL);
951 delete osthread;
952 return false;
953 }
954
955 // Store pthread info into the OSThread
956 osthread->set_pthread_id(tid);
957
958 // Wait until child thread is either initialized or aborted
959 {
960 Monitor* sync_with_child = osthread->startThread_lock();
961 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
962 while ((state = osthread->get_state()) == ALLOCATED) {
963 sync_with_child->wait_without_safepoint_check();
964 }
965 }
966 }
967
968 // Aborted due to thread limit being reached
969 if (state == ZOMBIE) {
970 thread->set_osthread(NULL);
971 delete osthread;
972 return false;
973 }
974
975 // The thread is returned suspended (in state INITIALIZED),
976 // and is started higher up in the call chain
977 assert(state == INITIALIZED, "race condition");
978 return true;
979 }
980
981 /////////////////////////////////////////////////////////////////////////////
982 // attach existing thread
983
984 // bootstrap the main thread
985 bool os::create_main_thread(JavaThread* thread) {
986 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
987 return create_attached_thread(thread);
988 }
989
990 bool os::create_attached_thread(JavaThread* thread) {
991 #ifdef ASSERT
992 thread->verify_not_published();
993 #endif
994
995 // Allocate the OSThread object
996 OSThread* osthread = new OSThread(NULL, NULL);
997
998 if (osthread == NULL) {
999 return false;
1000 }
1001
1002 // Store pthread info into the OSThread
1003 osthread->set_thread_id(os::Linux::gettid());
1004 osthread->set_pthread_id(::pthread_self());
1005
1006 // initialize floating point control register
1007 os::Linux::init_thread_fpu_state();
1008
1009 // Initial thread state is RUNNABLE
1010 osthread->set_state(RUNNABLE);
1011
1012 thread->set_osthread(osthread);
1013
1014 if (UseNUMA) {
1015 int lgrp_id = os::numa_get_group_id();
1016 if (lgrp_id != -1) {
1017 thread->set_lgrp_id(lgrp_id);
1018 }
1019 }
1020
1021 if (os::is_primordial_thread()) {
1022 // If current thread is primordial thread, its stack is mapped on demand,
1023 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1024 // the entire stack region to avoid SEGV in stack banging.
1025 // It is also useful to get around the heap-stack-gap problem on SuSE
1026 // kernel (see 4821821 for details). We first expand stack to the top
1027 // of yellow zone, then enable stack yellow zone (order is significant,
1028 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1029 // is no gap between the last two virtual memory regions.
1030
1031 JavaThread *jt = (JavaThread *)thread;
1032 address addr = jt->stack_reserved_zone_base();
1033 assert(addr != NULL, "initialization problem?");
1034 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1035
1036 osthread->set_expanding_stack();
1037 os::Linux::manually_expand_stack(jt, addr);
1038 osthread->clear_expanding_stack();
1039 }
1040
1041 // initialize signal mask for this thread
1042 // and save the caller's signal mask
1043 os::Linux::hotspot_sigmask(thread);
1044
1045 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
1046 os::current_thread_id(), (uintx) pthread_self());
1047
1048 return true;
1049 }
1050
1051 void os::pd_start_thread(Thread* thread) {
1052 OSThread * osthread = thread->osthread();
1053 assert(osthread->get_state() != INITIALIZED, "just checking");
1054 Monitor* sync_with_child = osthread->startThread_lock();
1055 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1056 sync_with_child->notify();
1057 }
1058
1059 // Free Linux resources related to the OSThread
1060 void os::free_thread(OSThread* osthread) {
1061 assert(osthread != NULL, "osthread not set");
1062
1063 // We are told to free resources of the argument thread,
1064 // but we can only really operate on the current thread.
1065 assert(Thread::current()->osthread() == osthread,
1066 "os::free_thread but not current thread");
1067
1068 #ifdef ASSERT
1069 sigset_t current;
1070 sigemptyset(¤t);
1071 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1072 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
1073 #endif
1074
1075 // Restore caller's signal mask
1076 sigset_t sigmask = osthread->caller_sigmask();
1077 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1078
1079 delete osthread;
1080 }
1081
1082 //////////////////////////////////////////////////////////////////////////////
1083 // primordial thread
1084
1085 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1086 bool os::is_primordial_thread(void) {
1087 if (suppress_primordial_thread_resolution) {
1088 return false;
1089 }
1090 char dummy;
1091 // If called before init complete, thread stack bottom will be null.
1092 // Can be called if fatal error occurs before initialization.
1093 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1094 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1095 os::Linux::initial_thread_stack_size() != 0,
1096 "os::init did not locate primordial thread's stack region");
1097 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1098 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1099 os::Linux::initial_thread_stack_size()) {
1100 return true;
1101 } else {
1102 return false;
1103 }
1104 }
1105
1106 // Find the virtual memory area that contains addr
1107 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1108 FILE *fp = fopen("/proc/self/maps", "r");
1109 if (fp) {
1110 address low, high;
1111 while (!feof(fp)) {
1112 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1113 if (low <= addr && addr < high) {
1114 if (vma_low) *vma_low = low;
1115 if (vma_high) *vma_high = high;
1116 fclose(fp);
1117 return true;
1118 }
1119 }
1120 for (;;) {
1121 int ch = fgetc(fp);
1122 if (ch == EOF || ch == (int)'\n') break;
1123 }
1124 }
1125 fclose(fp);
1126 }
1127 return false;
1128 }
1129
1130 // Locate primordial thread stack. This special handling of primordial thread stack
1131 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1132 // bogus value for the primordial process thread. While the launcher has created
1133 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1134 // JNI invocation API from a primordial thread.
1135 void os::Linux::capture_initial_stack(size_t max_size) {
1136
1137 // max_size is either 0 (which means accept OS default for thread stacks) or
1138 // a user-specified value known to be at least the minimum needed. If we
1139 // are actually on the primordial thread we can make it appear that we have a
1140 // smaller max_size stack by inserting the guard pages at that location. But we
1141 // cannot do anything to emulate a larger stack than what has been provided by
1142 // the OS or threading library. In fact if we try to use a stack greater than
1143 // what is set by rlimit then we will crash the hosting process.
1144
1145 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1146 // If this is "unlimited" then it will be a huge value.
1147 struct rlimit rlim;
1148 getrlimit(RLIMIT_STACK, &rlim);
1149 size_t stack_size = rlim.rlim_cur;
1150
1151 // 6308388: a bug in ld.so will relocate its own .data section to the
1152 // lower end of primordial stack; reduce ulimit -s value a little bit
1153 // so we won't install guard page on ld.so's data section.
1154 // But ensure we don't underflow the stack size - allow 1 page spare
1155 if (stack_size >= (size_t)(3 * page_size())) {
1156 stack_size -= 2 * page_size();
1157 }
1158
1159 // Try to figure out where the stack base (top) is. This is harder.
1160 //
1161 // When an application is started, glibc saves the initial stack pointer in
1162 // a global variable "__libc_stack_end", which is then used by system
1163 // libraries. __libc_stack_end should be pretty close to stack top. The
1164 // variable is available since the very early days. However, because it is
1165 // a private interface, it could disappear in the future.
1166 //
1167 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1168 // to __libc_stack_end, it is very close to stack top, but isn't the real
1169 // stack top. Note that /proc may not exist if VM is running as a chroot
1170 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1171 // /proc/<pid>/stat could change in the future (though unlikely).
1172 //
1173 // We try __libc_stack_end first. If that doesn't work, look for
1174 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1175 // as a hint, which should work well in most cases.
1176
1177 uintptr_t stack_start;
1178
1179 // try __libc_stack_end first
1180 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1181 if (p && *p) {
1182 stack_start = *p;
1183 } else {
1184 // see if we can get the start_stack field from /proc/self/stat
1185 FILE *fp;
1186 int pid;
1187 char state;
1188 int ppid;
1189 int pgrp;
1190 int session;
1191 int nr;
1192 int tpgrp;
1193 unsigned long flags;
1194 unsigned long minflt;
1195 unsigned long cminflt;
1196 unsigned long majflt;
1197 unsigned long cmajflt;
1198 unsigned long utime;
1199 unsigned long stime;
1200 long cutime;
1201 long cstime;
1202 long prio;
1203 long nice;
1204 long junk;
1205 long it_real;
1206 uintptr_t start;
1207 uintptr_t vsize;
1208 intptr_t rss;
1209 uintptr_t rsslim;
1210 uintptr_t scodes;
1211 uintptr_t ecode;
1212 int i;
1213
1214 // Figure what the primordial thread stack base is. Code is inspired
1215 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1216 // followed by command name surrounded by parentheses, state, etc.
1217 char stat[2048];
1218 int statlen;
1219
1220 fp = fopen("/proc/self/stat", "r");
1221 if (fp) {
1222 statlen = fread(stat, 1, 2047, fp);
1223 stat[statlen] = '\0';
1224 fclose(fp);
1225
1226 // Skip pid and the command string. Note that we could be dealing with
1227 // weird command names, e.g. user could decide to rename java launcher
1228 // to "java 1.4.2 :)", then the stat file would look like
1229 // 1234 (java 1.4.2 :)) R ... ...
1230 // We don't really need to know the command string, just find the last
1231 // occurrence of ")" and then start parsing from there. See bug 4726580.
1232 char * s = strrchr(stat, ')');
1233
1234 i = 0;
1235 if (s) {
1236 // Skip blank chars
1237 do { s++; } while (s && isspace(*s));
1238
1239 #define _UFM UINTX_FORMAT
1240 #define _DFM INTX_FORMAT
1241
1242 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1243 // 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
1244 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,
1245 &state, // 3 %c
1246 &ppid, // 4 %d
1247 &pgrp, // 5 %d
1248 &session, // 6 %d
1249 &nr, // 7 %d
1250 &tpgrp, // 8 %d
1251 &flags, // 9 %lu
1252 &minflt, // 10 %lu
1253 &cminflt, // 11 %lu
1254 &majflt, // 12 %lu
1255 &cmajflt, // 13 %lu
1256 &utime, // 14 %lu
1257 &stime, // 15 %lu
1258 &cutime, // 16 %ld
1259 &cstime, // 17 %ld
1260 &prio, // 18 %ld
1261 &nice, // 19 %ld
1262 &junk, // 20 %ld
1263 &it_real, // 21 %ld
1264 &start, // 22 UINTX_FORMAT
1265 &vsize, // 23 UINTX_FORMAT
1266 &rss, // 24 INTX_FORMAT
1267 &rsslim, // 25 UINTX_FORMAT
1268 &scodes, // 26 UINTX_FORMAT
1269 &ecode, // 27 UINTX_FORMAT
1270 &stack_start); // 28 UINTX_FORMAT
1271 }
1272
1273 #undef _UFM
1274 #undef _DFM
1275
1276 if (i != 28 - 2) {
1277 assert(false, "Bad conversion from /proc/self/stat");
1278 // product mode - assume we are the primordial thread, good luck in the
1279 // embedded case.
1280 warning("Can't detect primordial thread stack location - bad conversion");
1281 stack_start = (uintptr_t) &rlim;
1282 }
1283 } else {
1284 // For some reason we can't open /proc/self/stat (for example, running on
1285 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1286 // most cases, so don't abort:
1287 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1288 stack_start = (uintptr_t) &rlim;
1289 }
1290 }
1291
1292 // Now we have a pointer (stack_start) very close to the stack top, the
1293 // next thing to do is to figure out the exact location of stack top. We
1294 // can find out the virtual memory area that contains stack_start by
1295 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1296 // and its upper limit is the real stack top. (again, this would fail if
1297 // running inside chroot, because /proc may not exist.)
1298
1299 uintptr_t stack_top;
1300 address low, high;
1301 if (find_vma((address)stack_start, &low, &high)) {
1302 // success, "high" is the true stack top. (ignore "low", because initial
1303 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1304 stack_top = (uintptr_t)high;
1305 } else {
1306 // failed, likely because /proc/self/maps does not exist
1307 warning("Can't detect primordial thread stack location - find_vma failed");
1308 // best effort: stack_start is normally within a few pages below the real
1309 // stack top, use it as stack top, and reduce stack size so we won't put
1310 // guard page outside stack.
1311 stack_top = stack_start;
1312 stack_size -= 16 * page_size();
1313 }
1314
1315 // stack_top could be partially down the page so align it
1316 stack_top = align_up(stack_top, page_size());
1317
1318 // Allowed stack value is minimum of max_size and what we derived from rlimit
1319 if (max_size > 0) {
1320 _initial_thread_stack_size = MIN2(max_size, stack_size);
1321 } else {
1322 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1323 // clamp it at 8MB as we do on Solaris
1324 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1325 }
1326 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1327 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1328
1329 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1330
1331 if (log_is_enabled(Info, os, thread)) {
1332 // See if we seem to be on primordial process thread
1333 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1334 uintptr_t(&rlim) < stack_top;
1335
1336 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1337 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1338 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1339 stack_top, intptr_t(_initial_thread_stack_bottom));
1340 }
1341 }
1342
1343 ////////////////////////////////////////////////////////////////////////////////
1344 // time support
1345
1346 #ifndef SUPPORTS_CLOCK_MONOTONIC
1347 #error "Build platform doesn't support clock_gettime and related functionality"
1348 #endif
1349
1350 // Time since start-up in seconds to a fine granularity.
1351 // Used by VMSelfDestructTimer and the MemProfiler.
1352 double os::elapsedTime() {
1353
1354 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1355 }
1356
1357 jlong os::elapsed_counter() {
1358 return javaTimeNanos() - initial_time_count;
1359 }
1360
1361 jlong os::elapsed_frequency() {
1362 return NANOSECS_PER_SEC; // nanosecond resolution
1363 }
1364
1365 bool os::supports_vtime() { return true; }
1366
1367 double os::elapsedVTime() {
1368 struct rusage usage;
1369 int retval = getrusage(RUSAGE_THREAD, &usage);
1370 if (retval == 0) {
1371 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);
1372 } else {
1373 // better than nothing, but not much
1374 return elapsedTime();
1375 }
1376 }
1377
1378 jlong os::javaTimeMillis() {
1379 timeval time;
1380 int status = gettimeofday(&time, NULL);
1381 assert(status != -1, "linux error");
1382 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1383 }
1384
1385 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1386 timeval time;
1387 int status = gettimeofday(&time, NULL);
1388 assert(status != -1, "linux error");
1389 seconds = jlong(time.tv_sec);
1390 nanos = jlong(time.tv_usec) * 1000;
1391 }
1392
1393 void os::Linux::fast_thread_clock_init() {
1394 if (!UseLinuxPosixThreadCPUClocks) {
1395 return;
1396 }
1397 clockid_t clockid;
1398 struct timespec tp;
1399 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1400 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1401
1402 // Switch to using fast clocks for thread cpu time if
1403 // the clock_getres() returns 0 error code.
1404 // Note, that some kernels may support the current thread
1405 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1406 // returned by the pthread_getcpuclockid().
1407 // If the fast Posix clocks are supported then the clock_getres()
1408 // must return at least tp.tv_sec == 0 which means a resolution
1409 // better than 1 sec. This is extra check for reliability.
1410
1411 if (pthread_getcpuclockid_func &&
1412 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1413 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1414 _supports_fast_thread_cpu_time = true;
1415 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1416 }
1417 }
1418
1419 jlong os::javaTimeNanos() {
1420 if (os::supports_monotonic_clock()) {
1421 struct timespec tp;
1422 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1423 assert(status == 0, "gettime error");
1424 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1425 return result;
1426 } else {
1427 timeval time;
1428 int status = gettimeofday(&time, NULL);
1429 assert(status != -1, "linux error");
1430 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1431 return 1000 * usecs;
1432 }
1433 }
1434
1435 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1436 if (os::supports_monotonic_clock()) {
1437 info_ptr->max_value = ALL_64_BITS;
1438
1439 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1440 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1441 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1442 } else {
1443 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1444 info_ptr->max_value = ALL_64_BITS;
1445
1446 // gettimeofday is a real time clock so it skips
1447 info_ptr->may_skip_backward = true;
1448 info_ptr->may_skip_forward = true;
1449 }
1450
1451 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1452 }
1453
1454 // Return the real, user, and system times in seconds from an
1455 // arbitrary fixed point in the past.
1456 bool os::getTimesSecs(double* process_real_time,
1457 double* process_user_time,
1458 double* process_system_time) {
1459 struct tms ticks;
1460 clock_t real_ticks = times(&ticks);
1461
1462 if (real_ticks == (clock_t) (-1)) {
1463 return false;
1464 } else {
1465 double ticks_per_second = (double) clock_tics_per_sec;
1466 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1467 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1468 *process_real_time = ((double) real_ticks) / ticks_per_second;
1469
1470 return true;
1471 }
1472 }
1473
1474
1475 char * os::local_time_string(char *buf, size_t buflen) {
1476 struct tm t;
1477 time_t long_time;
1478 time(&long_time);
1479 localtime_r(&long_time, &t);
1480 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1481 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1482 t.tm_hour, t.tm_min, t.tm_sec);
1483 return buf;
1484 }
1485
1486 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1487 return localtime_r(clock, res);
1488 }
1489
1490 ////////////////////////////////////////////////////////////////////////////////
1491 // runtime exit support
1492
1493 // Note: os::shutdown() might be called very early during initialization, or
1494 // called from signal handler. Before adding something to os::shutdown(), make
1495 // sure it is async-safe and can handle partially initialized VM.
1496 void os::shutdown() {
1497
1498 // allow PerfMemory to attempt cleanup of any persistent resources
1499 perfMemory_exit();
1500
1501 // needs to remove object in file system
1502 AttachListener::abort();
1503
1504 // flush buffered output, finish log files
1505 ostream_abort();
1506
1507 // Check for abort hook
1508 abort_hook_t abort_hook = Arguments::abort_hook();
1509 if (abort_hook != NULL) {
1510 abort_hook();
1511 }
1512
1513 }
1514
1515 // Note: os::abort() might be called very early during initialization, or
1516 // called from signal handler. Before adding something to os::abort(), make
1517 // sure it is async-safe and can handle partially initialized VM.
1518 void os::abort(bool dump_core, void* siginfo, const void* context) {
1519 os::shutdown();
1520 if (dump_core) {
1521 if (DumpPrivateMappingsInCore) {
1522 ClassLoader::close_jrt_image();
1523 }
1524 ::abort(); // dump core
1525 }
1526
1527 ::exit(1);
1528 }
1529
1530 // Die immediately, no exit hook, no abort hook, no cleanup.
1531 // Dump a core file, if possible, for debugging.
1532 void os::die() {
1533 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1534 // For TimeoutInErrorHandlingTest.java, we just kill the VM
1535 // and don't take the time to generate a core file.
1536 os::signal_raise(SIGKILL);
1537 } else {
1538 ::abort();
1539 }
1540 }
1541
1542 // thread_id is kernel thread id (similar to Solaris LWP id)
1543 intx os::current_thread_id() { return os::Linux::gettid(); }
1544 int os::current_process_id() {
1545 return ::getpid();
1546 }
1547
1548 // DLL functions
1549
1550 const char* os::dll_file_extension() { return ".so"; }
1551
1552 // This must be hard coded because it's the system's temporary
1553 // directory not the java application's temp directory, ala java.io.tmpdir.
1554 const char* os::get_temp_directory() { return "/tmp"; }
1555
1556 static bool file_exists(const char* filename) {
1557 struct stat statbuf;
1558 if (filename == NULL || strlen(filename) == 0) {
1559 return false;
1560 }
1561 return os::stat(filename, &statbuf) == 0;
1562 }
1563
1564 // check if addr is inside libjvm.so
1565 bool os::address_is_in_vm(address addr) {
1566 static address libjvm_base_addr;
1567 Dl_info dlinfo;
1568
1569 if (libjvm_base_addr == NULL) {
1570 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1571 libjvm_base_addr = (address)dlinfo.dli_fbase;
1572 }
1573 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1574 }
1575
1576 if (dladdr((void *)addr, &dlinfo) != 0) {
1577 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1578 }
1579
1580 return false;
1581 }
1582
1583 bool os::dll_address_to_function_name(address addr, char *buf,
1584 int buflen, int *offset,
1585 bool demangle) {
1586 // buf is not optional, but offset is optional
1587 assert(buf != NULL, "sanity check");
1588
1589 Dl_info dlinfo;
1590
1591 if (dladdr((void*)addr, &dlinfo) != 0) {
1592 // see if we have a matching symbol
1593 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1594 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1595 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1596 }
1597 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1598 return true;
1599 }
1600 // no matching symbol so try for just file info
1601 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1602 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1603 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1604 return true;
1605 }
1606 }
1607 }
1608
1609 buf[0] = '\0';
1610 if (offset != NULL) *offset = -1;
1611 return false;
1612 }
1613
1614 struct _address_to_library_name {
1615 address addr; // input : memory address
1616 size_t buflen; // size of fname
1617 char* fname; // output: library name
1618 address base; // library base addr
1619 };
1620
1621 static int address_to_library_name_callback(struct dl_phdr_info *info,
1622 size_t size, void *data) {
1623 int i;
1624 bool found = false;
1625 address libbase = NULL;
1626 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1627
1628 // iterate through all loadable segments
1629 for (i = 0; i < info->dlpi_phnum; i++) {
1630 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1631 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1632 // base address of a library is the lowest address of its loaded
1633 // segments.
1634 if (libbase == NULL || libbase > segbase) {
1635 libbase = segbase;
1636 }
1637 // see if 'addr' is within current segment
1638 if (segbase <= d->addr &&
1639 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1640 found = true;
1641 }
1642 }
1643 }
1644
1645 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1646 // so dll_address_to_library_name() can fall through to use dladdr() which
1647 // can figure out executable name from argv[0].
1648 if (found && info->dlpi_name && info->dlpi_name[0]) {
1649 d->base = libbase;
1650 if (d->fname) {
1651 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1652 }
1653 return 1;
1654 }
1655 return 0;
1656 }
1657
1658 bool os::dll_address_to_library_name(address addr, char* buf,
1659 int buflen, int* offset) {
1660 // buf is not optional, but offset is optional
1661 assert(buf != NULL, "sanity check");
1662
1663 Dl_info dlinfo;
1664 struct _address_to_library_name data;
1665
1666 // There is a bug in old glibc dladdr() implementation that it could resolve
1667 // to wrong library name if the .so file has a base address != NULL. Here
1668 // we iterate through the program headers of all loaded libraries to find
1669 // out which library 'addr' really belongs to. This workaround can be
1670 // removed once the minimum requirement for glibc is moved to 2.3.x.
1671 data.addr = addr;
1672 data.fname = buf;
1673 data.buflen = buflen;
1674 data.base = NULL;
1675 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1676
1677 if (rslt) {
1678 // buf already contains library name
1679 if (offset) *offset = addr - data.base;
1680 return true;
1681 }
1682 if (dladdr((void*)addr, &dlinfo) != 0) {
1683 if (dlinfo.dli_fname != NULL) {
1684 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1685 }
1686 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1687 *offset = addr - (address)dlinfo.dli_fbase;
1688 }
1689 return true;
1690 }
1691
1692 buf[0] = '\0';
1693 if (offset) *offset = -1;
1694 return false;
1695 }
1696
1697 // Loads .dll/.so and
1698 // in case of error it checks if .dll/.so was built for the
1699 // same architecture as Hotspot is running on
1700
1701
1702 // Remember the stack's state. The Linux dynamic linker will change
1703 // the stack to 'executable' at most once, so we must safepoint only once.
1704 bool os::Linux::_stack_is_executable = false;
1705
1706 // VM operation that loads a library. This is necessary if stack protection
1707 // of the Java stacks can be lost during loading the library. If we
1708 // do not stop the Java threads, they can stack overflow before the stacks
1709 // are protected again.
1710 class VM_LinuxDllLoad: public VM_Operation {
1711 private:
1712 const char *_filename;
1713 char *_ebuf;
1714 int _ebuflen;
1715 void *_lib;
1716 public:
1717 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1718 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1719 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1720 void doit() {
1721 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1722 os::Linux::_stack_is_executable = true;
1723 }
1724 void* loaded_library() { return _lib; }
1725 };
1726
1727 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1728 void * result = NULL;
1729 bool load_attempted = false;
1730
1731 log_info(os)("attempting shared library load of %s", filename);
1732
1733 // Check whether the library to load might change execution rights
1734 // of the stack. If they are changed, the protection of the stack
1735 // guard pages will be lost. We need a safepoint to fix this.
1736 //
1737 // See Linux man page execstack(8) for more info.
1738 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1739 if (!ElfFile::specifies_noexecstack(filename)) {
1740 if (!is_init_completed()) {
1741 os::Linux::_stack_is_executable = true;
1742 // This is OK - No Java threads have been created yet, and hence no
1743 // stack guard pages to fix.
1744 //
1745 // Dynamic loader will make all stacks executable after
1746 // this function returns, and will not do that again.
1747 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1748 } else {
1749 warning("You have loaded library %s which might have disabled stack guard. "
1750 "The VM will try to fix the stack guard now.\n"
1751 "It's highly recommended that you fix the library with "
1752 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1753 filename);
1754
1755 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1756 JavaThread *jt = JavaThread::current();
1757 if (jt->thread_state() != _thread_in_native) {
1758 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1759 // that requires ExecStack. Cannot enter safe point. Let's give up.
1760 warning("Unable to fix stack guard. Giving up.");
1761 } else {
1762 if (!LoadExecStackDllInVMThread) {
1763 // This is for the case where the DLL has an static
1764 // constructor function that executes JNI code. We cannot
1765 // load such DLLs in the VMThread.
1766 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1767 }
1768
1769 ThreadInVMfromNative tiv(jt);
1770 debug_only(VMNativeEntryWrapper vew;)
1771
1772 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1773 VMThread::execute(&op);
1774 if (LoadExecStackDllInVMThread) {
1775 result = op.loaded_library();
1776 }
1777 load_attempted = true;
1778 }
1779 }
1780 }
1781 }
1782
1783 if (!load_attempted) {
1784 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1785 }
1786
1787 if (result != NULL) {
1788 // Successful loading
1789 return result;
1790 }
1791
1792 Elf32_Ehdr elf_head;
1793 int diag_msg_max_length=ebuflen-strlen(ebuf);
1794 char* diag_msg_buf=ebuf+strlen(ebuf);
1795
1796 if (diag_msg_max_length==0) {
1797 // No more space in ebuf for additional diagnostics message
1798 return NULL;
1799 }
1800
1801
1802 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1803
1804 if (file_descriptor < 0) {
1805 // Can't open library, report dlerror() message
1806 return NULL;
1807 }
1808
1809 bool failed_to_read_elf_head=
1810 (sizeof(elf_head)!=
1811 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1812
1813 ::close(file_descriptor);
1814 if (failed_to_read_elf_head) {
1815 // file i/o error - report dlerror() msg
1816 return NULL;
1817 }
1818
1819 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1820 // handle invalid/out of range endianness values
1821 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1822 return NULL;
1823 }
1824
1825 #if defined(VM_LITTLE_ENDIAN)
1826 // VM is LE, shared object BE
1827 elf_head.e_machine = be16toh(elf_head.e_machine);
1828 #else
1829 // VM is BE, shared object LE
1830 elf_head.e_machine = le16toh(elf_head.e_machine);
1831 #endif
1832 }
1833
1834 typedef struct {
1835 Elf32_Half code; // Actual value as defined in elf.h
1836 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1837 unsigned char elf_class; // 32 or 64 bit
1838 unsigned char endianness; // MSB or LSB
1839 char* name; // String representation
1840 } arch_t;
1841
1842 #ifndef EM_AARCH64
1843 #define EM_AARCH64 183 /* ARM AARCH64 */
1844 #endif
1845 #ifndef EM_RISCV
1846 #define EM_RISCV 243 /* RISC-V */
1847 #endif
1848
1849 static const arch_t arch_array[]={
1850 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1851 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1852 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1853 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1854 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1855 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1856 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 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 __sparc) && (defined _LP64)
1884 static Elf32_Half running_arch_code=EM_SPARCV9;
1885 #elif (defined __sparc) && (!defined _LP64)
1886 static Elf32_Half running_arch_code=EM_SPARC;
1887 #elif (defined __powerpc64__)
1888 static Elf32_Half running_arch_code=EM_PPC64;
1889 #elif (defined __powerpc__)
1890 static Elf32_Half running_arch_code=EM_PPC;
1891 #elif (defined AARCH64)
1892 static Elf32_Half running_arch_code=EM_AARCH64;
1893 #elif (defined ARM)
1894 static Elf32_Half running_arch_code=EM_ARM;
1895 #elif (defined S390)
1896 static Elf32_Half running_arch_code=EM_S390;
1897 #elif (defined ALPHA)
1898 static Elf32_Half running_arch_code=EM_ALPHA;
1899 #elif (defined MIPSEL)
1900 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1901 #elif (defined PARISC)
1902 static Elf32_Half running_arch_code=EM_PARISC;
1903 #elif (defined MIPS)
1904 static Elf32_Half running_arch_code=EM_MIPS;
1905 #elif (defined M68K)
1906 static Elf32_Half running_arch_code=EM_68K;
1907 #elif (defined SH)
1908 static Elf32_Half running_arch_code=EM_SH;
1909 #elif (defined RISCV)
1910 static Elf32_Half running_arch_code=EM_RISCV;
1911 #else
1912 #error Method os::dll_load requires that one of following is defined:\
1913 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc
1914 #endif
1915
1916 // Identify compatibility class for VM's architecture and library's architecture
1917 // Obtain string descriptions for architectures
1918
1919 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1920 int running_arch_index=-1;
1921
1922 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1923 if (running_arch_code == arch_array[i].code) {
1924 running_arch_index = i;
1925 }
1926 if (lib_arch.code == arch_array[i].code) {
1927 lib_arch.compat_class = arch_array[i].compat_class;
1928 lib_arch.name = arch_array[i].name;
1929 }
1930 }
1931
1932 assert(running_arch_index != -1,
1933 "Didn't find running architecture code (running_arch_code) in arch_array");
1934 if (running_arch_index == -1) {
1935 // Even though running architecture detection failed
1936 // we may still continue with reporting dlerror() message
1937 return NULL;
1938 }
1939
1940 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1941 if (lib_arch.name != NULL) {
1942 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1943 " (Possible cause: can't load %s .so on a %s platform)",
1944 lib_arch.name, arch_array[running_arch_index].name);
1945 } else {
1946 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1947 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1948 lib_arch.code, arch_array[running_arch_index].name);
1949 }
1950 return NULL;
1951 }
1952
1953 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1954 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1955 return NULL;
1956 }
1957
1958 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1959 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1960 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1961 return NULL;
1962 }
1963
1964 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1965 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1966 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1967 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1968 return NULL;
1969 }
1970
1971 return NULL;
1972 }
1973
1974 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1975 int ebuflen) {
1976 void * result = ::dlopen(filename, RTLD_LAZY);
1977 if (result == NULL) {
1978 const char* error_report = ::dlerror();
1979 if (error_report == NULL) {
1980 error_report = "dlerror returned no error description";
1981 }
1982 if (ebuf != NULL && ebuflen > 0) {
1983 ::strncpy(ebuf, error_report, ebuflen-1);
1984 ebuf[ebuflen-1]='\0';
1985 }
1986 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1987 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1988 } else {
1989 Events::log(NULL, "Loaded shared library %s", filename);
1990 log_info(os)("shared library load of %s was successful", filename);
1991 }
1992 return result;
1993 }
1994
1995 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1996 int ebuflen) {
1997 void * result = NULL;
1998 if (LoadExecStackDllInVMThread) {
1999 result = dlopen_helper(filename, ebuf, ebuflen);
2000 }
2001
2002 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2003 // library that requires an executable stack, or which does not have this
2004 // stack attribute set, dlopen changes the stack attribute to executable. The
2005 // read protection of the guard pages gets lost.
2006 //
2007 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2008 // may have been queued at the same time.
2009
2010 if (!_stack_is_executable) {
2011 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2012 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2013 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
2014 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
2015 warning("Attempt to reguard stack yellow zone failed.");
2016 }
2017 }
2018 }
2019 }
2020
2021 return result;
2022 }
2023
2024 void* os::dll_lookup(void* handle, const char* name) {
2025 void* res = dlsym(handle, name);
2026 return res;
2027 }
2028
2029 void* os::get_default_process_handle() {
2030 return (void*)::dlopen(NULL, RTLD_LAZY);
2031 }
2032
2033 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
2034 int fd = ::open(filename, O_RDONLY);
2035 if (fd == -1) {
2036 return false;
2037 }
2038
2039 if (hdr != NULL) {
2040 st->print_cr("%s", hdr);
2041 }
2042
2043 char buf[33];
2044 int bytes;
2045 buf[32] = '\0';
2046 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
2047 st->print_raw(buf, bytes);
2048 }
2049
2050 ::close(fd);
2051
2052 return true;
2053 }
2054
2055 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st) {
2056 st->print_cr("%s:", header);
2057 if (!_print_ascii_file(filename, st)) {
2058 st->print_cr("<Not Available>");
2059 }
2060 }
2061
2062 void os::print_dll_info(outputStream *st) {
2063 st->print_cr("Dynamic libraries:");
2064
2065 char fname[32];
2066 pid_t pid = os::Linux::gettid();
2067
2068 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2069
2070 if (!_print_ascii_file(fname, st)) {
2071 st->print("Can not get library information for pid = %d\n", pid);
2072 }
2073 }
2074
2075 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2076 FILE *procmapsFile = NULL;
2077
2078 // Open the procfs maps file for the current process
2079 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2080 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2081 char line[PATH_MAX + 100];
2082
2083 // Read line by line from 'file'
2084 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2085 u8 base, top, inode;
2086 char name[sizeof(line)];
2087
2088 // Parse fields from line, discard perms, offset and device
2089 int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %*s %*s %*s " INT64_FORMAT " %s",
2090 &base, &top, &inode, name);
2091 // the last entry 'name' is empty for some entries, so we might have 3 matches instead of 4 for some lines
2092 if (matches < 3) continue;
2093 if (matches == 3) name[0] = '\0';
2094
2095 // Filter by inode 0 so that we only get file system mapped files.
2096 if (inode != 0) {
2097
2098 // Call callback with the fields of interest
2099 if(callback(name, (address)base, (address)top, param)) {
2100 // Oops abort, callback aborted
2101 fclose(procmapsFile);
2102 return 1;
2103 }
2104 }
2105 }
2106 fclose(procmapsFile);
2107 }
2108 return 0;
2109 }
2110
2111 void os::print_os_info_brief(outputStream* st) {
2112 os::Linux::print_distro_info(st);
2113
2114 os::Posix::print_uname_info(st);
2115
2116 os::Linux::print_libversion_info(st);
2117
2118 }
2119
2120 void os::print_os_info(outputStream* st) {
2121 st->print("OS:");
2122
2123 os::Linux::print_distro_info(st);
2124
2125 os::Posix::print_uname_info(st);
2126
2127 os::Linux::print_uptime_info(st);
2128
2129 // Print warning if unsafe chroot environment detected
2130 if (unsafe_chroot_detected) {
2131 st->print("WARNING!! ");
2132 st->print_cr("%s", unstable_chroot_error);
2133 }
2134
2135 os::Linux::print_libversion_info(st);
2136
2137 os::Posix::print_rlimit_info(st);
2138
2139 os::Posix::print_load_average(st);
2140
2141 os::Linux::print_full_memory_info(st);
2142
2143 os::Linux::print_proc_sys_info(st);
2144
2145 os::Linux::print_ld_preload_file(st);
2146
2147 os::Linux::print_container_info(st);
2148
2149 VM_Version::print_platform_virtualization_info(st);
2150
2151 os::Linux::print_steal_info(st);
2152 }
2153
2154 // Try to identify popular distros.
2155 // Most Linux distributions have a /etc/XXX-release file, which contains
2156 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2157 // file that also contains the OS version string. Some have more than one
2158 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2159 // /etc/redhat-release.), so the order is important.
2160 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2161 // their own specific XXX-release file as well as a redhat-release file.
2162 // Because of this the XXX-release file needs to be searched for before the
2163 // redhat-release file.
2164 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2165 // search for redhat-release / SuSE-release needs to be before lsb-release.
2166 // Since the lsb-release file is the new standard it needs to be searched
2167 // before the older style release files.
2168 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2169 // next to last resort. The os-release file is a new standard that contains
2170 // distribution information and the system-release file seems to be an old
2171 // standard that has been replaced by the lsb-release and os-release files.
2172 // Searching for the debian_version file is the last resort. It contains
2173 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2174 // "Debian " is printed before the contents of the debian_version file.
2175
2176 const char* distro_files[] = {
2177 "/etc/oracle-release",
2178 "/etc/mandriva-release",
2179 "/etc/mandrake-release",
2180 "/etc/sun-release",
2181 "/etc/redhat-release",
2182 "/etc/SuSE-release",
2183 "/etc/lsb-release",
2184 "/etc/turbolinux-release",
2185 "/etc/gentoo-release",
2186 "/etc/ltib-release",
2187 "/etc/angstrom-version",
2188 "/etc/system-release",
2189 "/etc/os-release",
2190 NULL };
2191
2192 void os::Linux::print_distro_info(outputStream* st) {
2193 for (int i = 0;; i++) {
2194 const char* file = distro_files[i];
2195 if (file == NULL) {
2196 break; // done
2197 }
2198 // If file prints, we found it.
2199 if (_print_ascii_file(file, st)) {
2200 return;
2201 }
2202 }
2203
2204 if (file_exists("/etc/debian_version")) {
2205 st->print("Debian ");
2206 _print_ascii_file("/etc/debian_version", st);
2207 } else {
2208 st->print("Linux");
2209 }
2210 st->cr();
2211 }
2212
2213 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2214 char buf[256];
2215 while (fgets(buf, sizeof(buf), fp)) {
2216 // Edit out extra stuff in expected format
2217 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2218 char* ptr = strstr(buf, "\""); // the name is in quotes
2219 if (ptr != NULL) {
2220 ptr++; // go beyond first quote
2221 char* nl = strchr(ptr, '\"');
2222 if (nl != NULL) *nl = '\0';
2223 strncpy(distro, ptr, length);
2224 } else {
2225 ptr = strstr(buf, "=");
2226 ptr++; // go beyond equals then
2227 char* nl = strchr(ptr, '\n');
2228 if (nl != NULL) *nl = '\0';
2229 strncpy(distro, ptr, length);
2230 }
2231 return;
2232 } else if (get_first_line) {
2233 char* nl = strchr(buf, '\n');
2234 if (nl != NULL) *nl = '\0';
2235 strncpy(distro, buf, length);
2236 return;
2237 }
2238 }
2239 // print last line and close
2240 char* nl = strchr(buf, '\n');
2241 if (nl != NULL) *nl = '\0';
2242 strncpy(distro, buf, length);
2243 }
2244
2245 static void parse_os_info(char* distro, size_t length, const char* file) {
2246 FILE* fp = fopen(file, "r");
2247 if (fp != NULL) {
2248 // if suse format, print out first line
2249 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2250 parse_os_info_helper(fp, distro, length, get_first_line);
2251 fclose(fp);
2252 }
2253 }
2254
2255 void os::get_summary_os_info(char* buf, size_t buflen) {
2256 for (int i = 0;; i++) {
2257 const char* file = distro_files[i];
2258 if (file == NULL) {
2259 break; // ran out of distro_files
2260 }
2261 if (file_exists(file)) {
2262 parse_os_info(buf, buflen, file);
2263 return;
2264 }
2265 }
2266 // special case for debian
2267 if (file_exists("/etc/debian_version")) {
2268 strncpy(buf, "Debian ", buflen);
2269 if (buflen > 7) {
2270 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2271 }
2272 } else {
2273 strncpy(buf, "Linux", buflen);
2274 }
2275 }
2276
2277 void os::Linux::print_libversion_info(outputStream* st) {
2278 // libc, pthread
2279 st->print("libc:");
2280 st->print("%s ", os::Linux::glibc_version());
2281 st->print("%s ", os::Linux::libpthread_version());
2282 st->cr();
2283 }
2284
2285 void os::Linux::print_proc_sys_info(outputStream* st) {
2286 st->cr();
2287 _print_ascii_file_h("/proc/sys/kernel/threads-max (system-wide limit on the number of threads)",
2288 "/proc/sys/kernel/threads-max", st);
2289 _print_ascii_file_h("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have)",
2290 "/proc/sys/vm/max_map_count", st);
2291 _print_ascii_file_h("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers)",
2292 "/proc/sys/kernel/pid_max", st);
2293 }
2294
2295 void os::Linux::print_full_memory_info(outputStream* st) {
2296 _print_ascii_file_h("\n/proc/meminfo", "/proc/meminfo", st);
2297 st->cr();
2298
2299 // some information regarding THPs; for details see
2300 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt
2301 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/enabled",
2302 "/sys/kernel/mm/transparent_hugepage/enabled", st);
2303 _print_ascii_file_h("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter)",
2304 "/sys/kernel/mm/transparent_hugepage/defrag", st);
2305 }
2306
2307 void os::Linux::print_ld_preload_file(outputStream* st) {
2308 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2309 st->cr();
2310 }
2311
2312 void os::Linux::print_uptime_info(outputStream* st) {
2313 struct sysinfo sinfo;
2314 int ret = sysinfo(&sinfo);
2315 if (ret == 0) {
2316 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
2317 }
2318 }
2319
2320
2321 void os::Linux::print_container_info(outputStream* st) {
2322 if (!OSContainer::is_containerized()) {
2323 return;
2324 }
2325
2326 st->print("container (cgroup) information:\n");
2327
2328 const char *p_ct = OSContainer::container_type();
2329 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2330
2331 char *p = OSContainer::cpu_cpuset_cpus();
2332 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2333 free(p);
2334
2335 p = OSContainer::cpu_cpuset_memory_nodes();
2336 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2337 free(p);
2338
2339 int i = OSContainer::active_processor_count();
2340 st->print("active_processor_count: ");
2341 if (i > 0) {
2342 st->print("%d\n", i);
2343 } else {
2344 st->print("not supported\n");
2345 }
2346
2347 i = OSContainer::cpu_quota();
2348 st->print("cpu_quota: ");
2349 if (i > 0) {
2350 st->print("%d\n", i);
2351 } else {
2352 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2353 }
2354
2355 i = OSContainer::cpu_period();
2356 st->print("cpu_period: ");
2357 if (i > 0) {
2358 st->print("%d\n", i);
2359 } else {
2360 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2361 }
2362
2363 i = OSContainer::cpu_shares();
2364 st->print("cpu_shares: ");
2365 if (i > 0) {
2366 st->print("%d\n", i);
2367 } else {
2368 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2369 }
2370
2371 jlong j = OSContainer::memory_limit_in_bytes();
2372 st->print("memory_limit_in_bytes: ");
2373 if (j > 0) {
2374 st->print(JLONG_FORMAT "\n", j);
2375 } else {
2376 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2377 }
2378
2379 j = OSContainer::memory_and_swap_limit_in_bytes();
2380 st->print("memory_and_swap_limit_in_bytes: ");
2381 if (j > 0) {
2382 st->print(JLONG_FORMAT "\n", j);
2383 } else {
2384 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2385 }
2386
2387 j = OSContainer::memory_soft_limit_in_bytes();
2388 st->print("memory_soft_limit_in_bytes: ");
2389 if (j > 0) {
2390 st->print(JLONG_FORMAT "\n", j);
2391 } else {
2392 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2393 }
2394
2395 j = OSContainer::OSContainer::memory_usage_in_bytes();
2396 st->print("memory_usage_in_bytes: ");
2397 if (j > 0) {
2398 st->print(JLONG_FORMAT "\n", j);
2399 } else {
2400 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2401 }
2402
2403 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2404 st->print("memory_max_usage_in_bytes: ");
2405 if (j > 0) {
2406 st->print(JLONG_FORMAT "\n", j);
2407 } else {
2408 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2409 }
2410 st->cr();
2411 }
2412
2413 void os::Linux::print_steal_info(outputStream* st) {
2414 if (has_initial_tick_info) {
2415 CPUPerfTicks pticks;
2416 bool res = os::Linux::get_tick_information(&pticks, -1);
2417
2418 if (res && pticks.has_steal_ticks) {
2419 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2420 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2421 double steal_ticks_perc = 0.0;
2422 if (total_ticks_difference != 0) {
2423 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2424 }
2425 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2426 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2427 }
2428 }
2429 }
2430
2431 void os::print_memory_info(outputStream* st) {
2432
2433 st->print("Memory:");
2434 st->print(" %dk page", os::vm_page_size()>>10);
2435
2436 // values in struct sysinfo are "unsigned long"
2437 struct sysinfo si;
2438 sysinfo(&si);
2439
2440 st->print(", physical " UINT64_FORMAT "k",
2441 os::physical_memory() >> 10);
2442 st->print("(" UINT64_FORMAT "k free)",
2443 os::available_memory() >> 10);
2444 st->print(", swap " UINT64_FORMAT "k",
2445 ((jlong)si.totalswap * si.mem_unit) >> 10);
2446 st->print("(" UINT64_FORMAT "k free)",
2447 ((jlong)si.freeswap * si.mem_unit) >> 10);
2448 st->cr();
2449 }
2450
2451 // Print the first "model name" line and the first "flags" line
2452 // that we find and nothing more. We assume "model name" comes
2453 // before "flags" so if we find a second "model name", then the
2454 // "flags" field is considered missing.
2455 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2456 #if defined(IA32) || defined(AMD64)
2457 // Other platforms have less repetitive cpuinfo files
2458 FILE *fp = fopen("/proc/cpuinfo", "r");
2459 if (fp) {
2460 while (!feof(fp)) {
2461 if (fgets(buf, buflen, fp)) {
2462 // Assume model name comes before flags
2463 bool model_name_printed = false;
2464 if (strstr(buf, "model name") != NULL) {
2465 if (!model_name_printed) {
2466 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2467 st->print_raw(buf);
2468 model_name_printed = true;
2469 } else {
2470 // model name printed but not flags? Odd, just return
2471 fclose(fp);
2472 return true;
2473 }
2474 }
2475 // print the flags line too
2476 if (strstr(buf, "flags") != NULL) {
2477 st->print_raw(buf);
2478 fclose(fp);
2479 return true;
2480 }
2481 }
2482 }
2483 fclose(fp);
2484 }
2485 #endif // x86 platforms
2486 return false;
2487 }
2488
2489 // additional information about CPU e.g. available frequency ranges
2490 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) {
2491 _print_ascii_file_h("Online cpus", "/sys/devices/system/cpu/online", st);
2492 _print_ascii_file_h("Offline cpus", "/sys/devices/system/cpu/offline", st);
2493
2494 if (ExtensiveErrorReports) {
2495 // cache related info (cpu 0, should be similar for other CPUs)
2496 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries
2497 char hbuf_level[60];
2498 char hbuf_type[60];
2499 char hbuf_size[60];
2500 char hbuf_coherency_line_size[80];
2501 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i);
2502 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i);
2503 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i);
2504 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i);
2505 if (file_exists(hbuf_level)) {
2506 _print_ascii_file_h("cache level", hbuf_level, st);
2507 _print_ascii_file_h("cache type", hbuf_type, st);
2508 _print_ascii_file_h("cache size", hbuf_size, st);
2509 _print_ascii_file_h("cache coherency line size", hbuf_coherency_line_size, st);
2510 }
2511 }
2512 }
2513
2514 // we miss the cpufreq entries on Power and s390x
2515 #if defined(IA32) || defined(AMD64)
2516 _print_ascii_file_h("BIOS frequency limitation", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st);
2517 _print_ascii_file_h("Frequency switch latency (ns)", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st);
2518 _print_ascii_file_h("Available cpu frequencies", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st);
2519 // min and max should be in the Available range but still print them (not all info might be available for all kernels)
2520 if (ExtensiveErrorReports) {
2521 _print_ascii_file_h("Maximum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st);
2522 _print_ascii_file_h("Minimum cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st);
2523 _print_ascii_file_h("Current cpu frequency", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st);
2524 }
2525 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling
2526 if (ExtensiveErrorReports) {
2527 _print_ascii_file_h("Available governors", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st);
2528 }
2529 _print_ascii_file_h("Current governor", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st);
2530 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt
2531 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g.
2532 // whole chip is not fully utilized
2533 _print_ascii_file_h("Core performance/turbo boost", "/sys/devices/system/cpu/cpufreq/boost", st);
2534 #endif
2535 }
2536
2537 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2538 // Only print the model name if the platform provides this as a summary
2539 if (!print_model_name_and_flags(st, buf, buflen)) {
2540 _print_ascii_file_h("\n/proc/cpuinfo", "/proc/cpuinfo", st);
2541 }
2542 print_sys_devices_cpu_info(st, buf, buflen);
2543 }
2544
2545 #if defined(AMD64) || defined(IA32) || defined(X32)
2546 const char* search_string = "model name";
2547 #elif defined(M68K)
2548 const char* search_string = "CPU";
2549 #elif defined(PPC64)
2550 const char* search_string = "cpu";
2551 #elif defined(S390)
2552 const char* search_string = "machine =";
2553 #elif defined(SPARC)
2554 const char* search_string = "cpu";
2555 #else
2556 const char* search_string = "Processor";
2557 #endif
2558
2559 // Parses the cpuinfo file for string representing the model name.
2560 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2561 FILE* fp = fopen("/proc/cpuinfo", "r");
2562 if (fp != NULL) {
2563 while (!feof(fp)) {
2564 char buf[256];
2565 if (fgets(buf, sizeof(buf), fp)) {
2566 char* start = strstr(buf, search_string);
2567 if (start != NULL) {
2568 char *ptr = start + strlen(search_string);
2569 char *end = buf + strlen(buf);
2570 while (ptr != end) {
2571 // skip whitespace and colon for the rest of the name.
2572 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2573 break;
2574 }
2575 ptr++;
2576 }
2577 if (ptr != end) {
2578 // reasonable string, get rid of newline and keep the rest
2579 char* nl = strchr(buf, '\n');
2580 if (nl != NULL) *nl = '\0';
2581 strncpy(cpuinfo, ptr, length);
2582 fclose(fp);
2583 return;
2584 }
2585 }
2586 }
2587 }
2588 fclose(fp);
2589 }
2590 // cpuinfo not found or parsing failed, just print generic string. The entire
2591 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2592 #if defined(AARCH64)
2593 strncpy(cpuinfo, "AArch64", length);
2594 #elif defined(AMD64)
2595 strncpy(cpuinfo, "x86_64", length);
2596 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2597 strncpy(cpuinfo, "ARM", length);
2598 #elif defined(IA32)
2599 strncpy(cpuinfo, "x86_32", length);
2600 #elif defined(IA64)
2601 strncpy(cpuinfo, "IA64", length);
2602 #elif defined(PPC)
2603 strncpy(cpuinfo, "PPC64", length);
2604 #elif defined(S390)
2605 strncpy(cpuinfo, "S390", length);
2606 #elif defined(SPARC)
2607 strncpy(cpuinfo, "sparcv9", length);
2608 #elif defined(ZERO_LIBARCH)
2609 strncpy(cpuinfo, ZERO_LIBARCH, length);
2610 #else
2611 strncpy(cpuinfo, "unknown", length);
2612 #endif
2613 }
2614
2615 static void print_signal_handler(outputStream* st, int sig,
2616 char* buf, size_t buflen);
2617
2618 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2619 st->print_cr("Signal Handlers:");
2620 print_signal_handler(st, SIGSEGV, buf, buflen);
2621 print_signal_handler(st, SIGBUS , buf, buflen);
2622 print_signal_handler(st, SIGFPE , buf, buflen);
2623 print_signal_handler(st, SIGPIPE, buf, buflen);
2624 print_signal_handler(st, SIGXFSZ, buf, buflen);
2625 print_signal_handler(st, SIGILL , buf, buflen);
2626 print_signal_handler(st, SR_signum, buf, buflen);
2627 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2628 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2629 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2630 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2631 #if defined(PPC64)
2632 print_signal_handler(st, SIGTRAP, buf, buflen);
2633 #endif
2634 }
2635
2636 static char saved_jvm_path[MAXPATHLEN] = {0};
2637
2638 // Find the full path to the current module, libjvm.so
2639 void os::jvm_path(char *buf, jint buflen) {
2640 // Error checking.
2641 if (buflen < MAXPATHLEN) {
2642 assert(false, "must use a large-enough buffer");
2643 buf[0] = '\0';
2644 return;
2645 }
2646 // Lazy resolve the path to current module.
2647 if (saved_jvm_path[0] != 0) {
2648 strcpy(buf, saved_jvm_path);
2649 return;
2650 }
2651
2652 char dli_fname[MAXPATHLEN];
2653 bool ret = dll_address_to_library_name(
2654 CAST_FROM_FN_PTR(address, os::jvm_path),
2655 dli_fname, sizeof(dli_fname), NULL);
2656 assert(ret, "cannot locate libjvm");
2657 char *rp = NULL;
2658 if (ret && dli_fname[0] != '\0') {
2659 rp = os::Posix::realpath(dli_fname, buf, buflen);
2660 }
2661 if (rp == NULL) {
2662 return;
2663 }
2664
2665 if (Arguments::sun_java_launcher_is_altjvm()) {
2666 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2667 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2668 // If "/jre/lib/" appears at the right place in the string, then
2669 // assume we are installed in a JDK and we're done. Otherwise, check
2670 // for a JAVA_HOME environment variable and fix up the path so it
2671 // looks like libjvm.so is installed there (append a fake suffix
2672 // hotspot/libjvm.so).
2673 const char *p = buf + strlen(buf) - 1;
2674 for (int count = 0; p > buf && count < 5; ++count) {
2675 for (--p; p > buf && *p != '/'; --p)
2676 /* empty */ ;
2677 }
2678
2679 if (strncmp(p, "/jre/lib/", 9) != 0) {
2680 // Look for JAVA_HOME in the environment.
2681 char* java_home_var = ::getenv("JAVA_HOME");
2682 if (java_home_var != NULL && java_home_var[0] != 0) {
2683 char* jrelib_p;
2684 int len;
2685
2686 // Check the current module name "libjvm.so".
2687 p = strrchr(buf, '/');
2688 if (p == NULL) {
2689 return;
2690 }
2691 assert(strstr(p, "/libjvm") == p, "invalid library name");
2692
2693 rp = os::Posix::realpath(java_home_var, buf, buflen);
2694 if (rp == NULL) {
2695 return;
2696 }
2697
2698 // determine if this is a legacy image or modules image
2699 // modules image doesn't have "jre" subdirectory
2700 len = strlen(buf);
2701 assert(len < buflen, "Ran out of buffer room");
2702 jrelib_p = buf + len;
2703 snprintf(jrelib_p, buflen-len, "/jre/lib");
2704 if (0 != access(buf, F_OK)) {
2705 snprintf(jrelib_p, buflen-len, "/lib");
2706 }
2707
2708 if (0 == access(buf, F_OK)) {
2709 // Use current module name "libjvm.so"
2710 len = strlen(buf);
2711 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2712 } else {
2713 // Go back to path of .so
2714 rp = os::Posix::realpath(dli_fname, buf, buflen);
2715 if (rp == NULL) {
2716 return;
2717 }
2718 }
2719 }
2720 }
2721 }
2722
2723 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2724 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2725 }
2726
2727 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2728 // no prefix required, not even "_"
2729 }
2730
2731 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2732 // no suffix required
2733 }
2734
2735 ////////////////////////////////////////////////////////////////////////////////
2736 // sun.misc.Signal support
2737
2738 static void UserHandler(int sig, void *siginfo, void *context) {
2739 // Ctrl-C is pressed during error reporting, likely because the error
2740 // handler fails to abort. Let VM die immediately.
2741 if (sig == SIGINT && VMError::is_error_reported()) {
2742 os::die();
2743 }
2744
2745 os::signal_notify(sig);
2746 }
2747
2748 void* os::user_handler() {
2749 return CAST_FROM_FN_PTR(void*, UserHandler);
2750 }
2751
2752 extern "C" {
2753 typedef void (*sa_handler_t)(int);
2754 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2755 }
2756
2757 void* os::signal(int signal_number, void* handler) {
2758 struct sigaction sigAct, oldSigAct;
2759
2760 sigfillset(&(sigAct.sa_mask));
2761 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2762 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2763
2764 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2765 // -1 means registration failed
2766 return (void *)-1;
2767 }
2768
2769 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2770 }
2771
2772 void os::signal_raise(int signal_number) {
2773 ::raise(signal_number);
2774 }
2775
2776 // The following code is moved from os.cpp for making this
2777 // code platform specific, which it is by its very nature.
2778
2779 // Will be modified when max signal is changed to be dynamic
2780 int os::sigexitnum_pd() {
2781 return NSIG;
2782 }
2783
2784 // a counter for each possible signal value
2785 static volatile jint pending_signals[NSIG+1] = { 0 };
2786
2787 // Linux(POSIX) specific hand shaking semaphore.
2788 static Semaphore* sig_sem = NULL;
2789 static PosixSemaphore sr_semaphore;
2790
2791 static void jdk_misc_signal_init() {
2792 // Initialize signal structures
2793 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2794
2795 // Initialize signal semaphore
2796 sig_sem = new Semaphore();
2797 }
2798
2799 void os::signal_notify(int sig) {
2800 if (sig_sem != NULL) {
2801 Atomic::inc(&pending_signals[sig]);
2802 sig_sem->signal();
2803 } else {
2804 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2805 // initialization isn't called.
2806 assert(ReduceSignalUsage, "signal semaphore should be created");
2807 }
2808 }
2809
2810 static int check_pending_signals() {
2811 for (;;) {
2812 for (int i = 0; i < NSIG + 1; i++) {
2813 jint n = pending_signals[i];
2814 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) {
2815 return i;
2816 }
2817 }
2818 JavaThread *thread = JavaThread::current();
2819 ThreadBlockInVM tbivm(thread);
2820
2821 bool threadIsSuspended;
2822 do {
2823 thread->set_suspend_equivalent();
2824 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2825 sig_sem->wait();
2826
2827 // were we externally suspended while we were waiting?
2828 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2829 if (threadIsSuspended) {
2830 // The semaphore has been incremented, but while we were waiting
2831 // another thread suspended us. We don't want to continue running
2832 // while suspended because that would surprise the thread that
2833 // suspended us.
2834 sig_sem->signal();
2835
2836 thread->java_suspend_self();
2837 }
2838 } while (threadIsSuspended);
2839 }
2840 }
2841
2842 int os::signal_wait() {
2843 return check_pending_signals();
2844 }
2845
2846 ////////////////////////////////////////////////////////////////////////////////
2847 // Virtual Memory
2848
2849 int os::vm_page_size() {
2850 // Seems redundant as all get out
2851 assert(os::Linux::page_size() != -1, "must call os::init");
2852 return os::Linux::page_size();
2853 }
2854
2855 // Solaris allocates memory by pages.
2856 int os::vm_allocation_granularity() {
2857 assert(os::Linux::page_size() != -1, "must call os::init");
2858 return os::Linux::page_size();
2859 }
2860
2861 // Rationale behind this function:
2862 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2863 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2864 // samples for JITted code. Here we create private executable mapping over the code cache
2865 // and then we can use standard (well, almost, as mapping can change) way to provide
2866 // info for the reporting script by storing timestamp and location of symbol
2867 void linux_wrap_code(char* base, size_t size) {
2868 static volatile jint cnt = 0;
2869
2870 if (!UseOprofile) {
2871 return;
2872 }
2873
2874 char buf[PATH_MAX+1];
2875 int num = Atomic::add(&cnt, 1);
2876
2877 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2878 os::get_temp_directory(), os::current_process_id(), num);
2879 unlink(buf);
2880
2881 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2882
2883 if (fd != -1) {
2884 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2885 if (rv != (off_t)-1) {
2886 if (::write(fd, "", 1) == 1) {
2887 mmap(base, size,
2888 PROT_READ|PROT_WRITE|PROT_EXEC,
2889 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2890 }
2891 }
2892 ::close(fd);
2893 unlink(buf);
2894 }
2895 }
2896
2897 static bool recoverable_mmap_error(int err) {
2898 // See if the error is one we can let the caller handle. This
2899 // list of errno values comes from JBS-6843484. I can't find a
2900 // Linux man page that documents this specific set of errno
2901 // values so while this list currently matches Solaris, it may
2902 // change as we gain experience with this failure mode.
2903 switch (err) {
2904 case EBADF:
2905 case EINVAL:
2906 case ENOTSUP:
2907 // let the caller deal with these errors
2908 return true;
2909
2910 default:
2911 // Any remaining errors on this OS can cause our reserved mapping
2912 // to be lost. That can cause confusion where different data
2913 // structures think they have the same memory mapped. The worst
2914 // scenario is if both the VM and a library think they have the
2915 // same memory mapped.
2916 return false;
2917 }
2918 }
2919
2920 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2921 int err) {
2922 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2923 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2924 os::strerror(err), err);
2925 }
2926
2927 static void warn_fail_commit_memory(char* addr, size_t size,
2928 size_t alignment_hint, bool exec,
2929 int err) {
2930 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2931 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2932 alignment_hint, exec, os::strerror(err), err);
2933 }
2934
2935 // NOTE: Linux kernel does not really reserve the pages for us.
2936 // All it does is to check if there are enough free pages
2937 // left at the time of mmap(). This could be a potential
2938 // problem.
2939 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2940 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2941 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2942 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2943 if (res != (uintptr_t) MAP_FAILED) {
2944 if (UseNUMAInterleaving) {
2945 numa_make_global(addr, size);
2946 }
2947 return 0;
2948 }
2949
2950 int err = errno; // save errno from mmap() call above
2951
2952 if (!recoverable_mmap_error(err)) {
2953 warn_fail_commit_memory(addr, size, exec, err);
2954 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2955 }
2956
2957 return err;
2958 }
2959
2960 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2961 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2962 }
2963
2964 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2965 const char* mesg) {
2966 assert(mesg != NULL, "mesg must be specified");
2967 int err = os::Linux::commit_memory_impl(addr, size, exec);
2968 if (err != 0) {
2969 // the caller wants all commit errors to exit with the specified mesg:
2970 warn_fail_commit_memory(addr, size, exec, err);
2971 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2972 }
2973 }
2974
2975 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2976 #ifndef MAP_HUGETLB
2977 #define MAP_HUGETLB 0x40000
2978 #endif
2979
2980 // If mmap flags are set with MAP_HUGETLB and the system supports multiple
2981 // huge page sizes, flag bits [26:31] can be used to encode the log2 of the
2982 // desired huge page size. Otherwise, the system's default huge page size will be used.
2983 // See mmap(2) man page for more info (since Linux 3.8).
2984 // https://lwn.net/Articles/533499/
2985 #ifndef MAP_HUGE_SHIFT
2986 #define MAP_HUGE_SHIFT 26
2987 #endif
2988
2989 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2990 #ifndef MADV_HUGEPAGE
2991 #define MADV_HUGEPAGE 14
2992 #endif
2993
2994 int os::Linux::commit_memory_impl(char* addr, size_t size,
2995 size_t alignment_hint, bool exec) {
2996 int err = os::Linux::commit_memory_impl(addr, size, exec);
2997 if (err == 0) {
2998 realign_memory(addr, size, alignment_hint);
2999 }
3000 return err;
3001 }
3002
3003 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
3004 bool exec) {
3005 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
3006 }
3007
3008 void os::pd_commit_memory_or_exit(char* addr, size_t size,
3009 size_t alignment_hint, bool exec,
3010 const char* mesg) {
3011 assert(mesg != NULL, "mesg must be specified");
3012 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
3013 if (err != 0) {
3014 // the caller wants all commit errors to exit with the specified mesg:
3015 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
3016 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
3017 }
3018 }
3019
3020 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
3021 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
3022 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
3023 // be supported or the memory may already be backed by huge pages.
3024 ::madvise(addr, bytes, MADV_HUGEPAGE);
3025 }
3026 }
3027
3028 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
3029 // This method works by doing an mmap over an existing mmaping and effectively discarding
3030 // the existing pages. However it won't work for SHM-based large pages that cannot be
3031 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
3032 // small pages on top of the SHM segment. This method always works for small pages, so we
3033 // allow that in any case.
3034 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
3035 commit_memory(addr, bytes, alignment_hint, !ExecMem);
3036 }
3037 }
3038
3039 void os::numa_make_global(char *addr, size_t bytes) {
3040 Linux::numa_interleave_memory(addr, bytes);
3041 }
3042
3043 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
3044 // bind policy to MPOL_PREFERRED for the current thread.
3045 #define USE_MPOL_PREFERRED 0
3046
3047 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
3048 // To make NUMA and large pages more robust when both enabled, we need to ease
3049 // the requirements on where the memory should be allocated. MPOL_BIND is the
3050 // default policy and it will force memory to be allocated on the specified
3051 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
3052 // the specified node, but will not force it. Using this policy will prevent
3053 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
3054 // free large pages.
3055 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
3056 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
3057 }
3058
3059 bool os::numa_topology_changed() { return false; }
3060
3061 size_t os::numa_get_groups_num() {
3062 // Return just the number of nodes in which it's possible to allocate memory
3063 // (in numa terminology, configured nodes).
3064 return Linux::numa_num_configured_nodes();
3065 }
3066
3067 int os::numa_get_group_id() {
3068 int cpu_id = Linux::sched_getcpu();
3069 if (cpu_id != -1) {
3070 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
3071 if (lgrp_id != -1) {
3072 return lgrp_id;
3073 }
3074 }
3075 return 0;
3076 }
3077
3078 int os::numa_get_group_id_for_address(const void* address) {
3079 void** pages = const_cast<void**>(&address);
3080 int id = -1;
3081
3082 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
3083 return -1;
3084 }
3085 if (id < 0) {
3086 return -1;
3087 }
3088 return id;
3089 }
3090
3091 int os::Linux::get_existing_num_nodes() {
3092 int node;
3093 int highest_node_number = Linux::numa_max_node();
3094 int num_nodes = 0;
3095
3096 // Get the total number of nodes in the system including nodes without memory.
3097 for (node = 0; node <= highest_node_number; node++) {
3098 if (is_node_in_existing_nodes(node)) {
3099 num_nodes++;
3100 }
3101 }
3102 return num_nodes;
3103 }
3104
3105 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
3106 int highest_node_number = Linux::numa_max_node();
3107 size_t i = 0;
3108
3109 // Map all node ids in which it is possible to allocate memory. Also nodes are
3110 // not always consecutively available, i.e. available from 0 to the highest
3111 // node number. If the nodes have been bound explicitly using numactl membind,
3112 // then allocate memory from those nodes only.
3113 for (int node = 0; node <= highest_node_number; node++) {
3114 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
3115 ids[i++] = node;
3116 }
3117 }
3118 return i;
3119 }
3120
3121 bool os::get_page_info(char *start, page_info* info) {
3122 return false;
3123 }
3124
3125 char *os::scan_pages(char *start, char* end, page_info* page_expected,
3126 page_info* page_found) {
3127 return end;
3128 }
3129
3130
3131 int os::Linux::sched_getcpu_syscall(void) {
3132 unsigned int cpu = 0;
3133 int retval = -1;
3134
3135 #if defined(IA32)
3136 #ifndef SYS_getcpu
3137 #define SYS_getcpu 318
3138 #endif
3139 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
3140 #elif defined(AMD64)
3141 // Unfortunately we have to bring all these macros here from vsyscall.h
3142 // to be able to compile on old linuxes.
3143 #define __NR_vgetcpu 2
3144 #define VSYSCALL_START (-10UL << 20)
3145 #define VSYSCALL_SIZE 1024
3146 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
3147 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
3148 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
3149 retval = vgetcpu(&cpu, NULL, NULL);
3150 #endif
3151
3152 return (retval == -1) ? retval : cpu;
3153 }
3154
3155 void os::Linux::sched_getcpu_init() {
3156 // sched_getcpu() should be in libc.
3157 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3158 dlsym(RTLD_DEFAULT, "sched_getcpu")));
3159
3160 // If it's not, try a direct syscall.
3161 if (sched_getcpu() == -1) {
3162 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3163 (void*)&sched_getcpu_syscall));
3164 }
3165
3166 if (sched_getcpu() == -1) {
3167 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
3168 }
3169 }
3170
3171 // Something to do with the numa-aware allocator needs these symbols
3172 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3173 extern "C" JNIEXPORT void numa_error(char *where) { }
3174
3175 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3176 // load symbol from base version instead.
3177 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3178 void *f = dlvsym(handle, name, "libnuma_1.1");
3179 if (f == NULL) {
3180 f = dlsym(handle, name);
3181 }
3182 return f;
3183 }
3184
3185 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3186 // Return NULL if the symbol is not defined in this particular version.
3187 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3188 return dlvsym(handle, name, "libnuma_1.2");
3189 }
3190
3191 bool os::Linux::libnuma_init() {
3192 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3193 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3194 if (handle != NULL) {
3195 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3196 libnuma_dlsym(handle, "numa_node_to_cpus")));
3197 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3198 libnuma_dlsym(handle, "numa_max_node")));
3199 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3200 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3201 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3202 libnuma_dlsym(handle, "numa_available")));
3203 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3204 libnuma_dlsym(handle, "numa_tonode_memory")));
3205 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3206 libnuma_dlsym(handle, "numa_interleave_memory")));
3207 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3208 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3209 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3210 libnuma_dlsym(handle, "numa_set_bind_policy")));
3211 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3212 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3213 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3214 libnuma_dlsym(handle, "numa_distance")));
3215 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3216 libnuma_v2_dlsym(handle, "numa_get_membind")));
3217 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3218 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3219 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3220 libnuma_dlsym(handle, "numa_move_pages")));
3221 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t,
3222 libnuma_dlsym(handle, "numa_set_preferred")));
3223
3224 if (numa_available() != -1) {
3225 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3226 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3227 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3228 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3229 set_numa_membind_bitmask(_numa_get_membind());
3230 // Create an index -> node mapping, since nodes are not always consecutive
3231 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3232 rebuild_nindex_to_node_map();
3233 // Create a cpu -> node mapping
3234 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3235 rebuild_cpu_to_node_map();
3236 return true;
3237 }
3238 }
3239 }
3240 return false;
3241 }
3242
3243 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3244 // Creating guard page is very expensive. Java thread has HotSpot
3245 // guard pages, only enable glibc guard page for non-Java threads.
3246 // (Remember: compiler thread is a Java thread, too!)
3247 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3248 }
3249
3250 void os::Linux::rebuild_nindex_to_node_map() {
3251 int highest_node_number = Linux::numa_max_node();
3252
3253 nindex_to_node()->clear();
3254 for (int node = 0; node <= highest_node_number; node++) {
3255 if (Linux::is_node_in_existing_nodes(node)) {
3256 nindex_to_node()->append(node);
3257 }
3258 }
3259 }
3260
3261 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3262 // The table is later used in get_node_by_cpu().
3263 void os::Linux::rebuild_cpu_to_node_map() {
3264 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3265 // in libnuma (possible values are starting from 16,
3266 // and continuing up with every other power of 2, but less
3267 // than the maximum number of CPUs supported by kernel), and
3268 // is a subject to change (in libnuma version 2 the requirements
3269 // are more reasonable) we'll just hardcode the number they use
3270 // in the library.
3271 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3272
3273 size_t cpu_num = processor_count();
3274 size_t cpu_map_size = NCPUS / BitsPerCLong;
3275 size_t cpu_map_valid_size =
3276 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3277
3278 cpu_to_node()->clear();
3279 cpu_to_node()->at_grow(cpu_num - 1);
3280
3281 size_t node_num = get_existing_num_nodes();
3282
3283 int distance = 0;
3284 int closest_distance = INT_MAX;
3285 int closest_node = 0;
3286 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3287 for (size_t i = 0; i < node_num; i++) {
3288 // Check if node is configured (not a memory-less node). If it is not, find
3289 // the closest configured node. Check also if node is bound, i.e. it's allowed
3290 // to allocate memory from the node. If it's not allowed, map cpus in that node
3291 // to the closest node from which memory allocation is allowed.
3292 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3293 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3294 closest_distance = INT_MAX;
3295 // Check distance from all remaining nodes in the system. Ignore distance
3296 // from itself, from another non-configured node, and from another non-bound
3297 // node.
3298 for (size_t m = 0; m < node_num; m++) {
3299 if (m != i &&
3300 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3301 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3302 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3303 // If a closest node is found, update. There is always at least one
3304 // configured and bound node in the system so there is always at least
3305 // one node close.
3306 if (distance != 0 && distance < closest_distance) {
3307 closest_distance = distance;
3308 closest_node = nindex_to_node()->at(m);
3309 }
3310 }
3311 }
3312 } else {
3313 // Current node is already a configured node.
3314 closest_node = nindex_to_node()->at(i);
3315 }
3316
3317 // Get cpus from the original node and map them to the closest node. If node
3318 // is a configured node (not a memory-less node), then original node and
3319 // closest node are the same.
3320 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3321 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3322 if (cpu_map[j] != 0) {
3323 for (size_t k = 0; k < BitsPerCLong; k++) {
3324 if (cpu_map[j] & (1UL << k)) {
3325 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3326 }
3327 }
3328 }
3329 }
3330 }
3331 }
3332 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3333 }
3334
3335 int os::Linux::get_node_by_cpu(int cpu_id) {
3336 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3337 return cpu_to_node()->at(cpu_id);
3338 }
3339 return -1;
3340 }
3341
3342 GrowableArray<int>* os::Linux::_cpu_to_node;
3343 GrowableArray<int>* os::Linux::_nindex_to_node;
3344 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3345 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3346 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3347 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3348 os::Linux::numa_available_func_t os::Linux::_numa_available;
3349 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3350 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3351 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3352 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3353 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3354 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3355 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3356 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3357 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3358 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred;
3359 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3360 unsigned long* os::Linux::_numa_all_nodes;
3361 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3362 struct bitmask* os::Linux::_numa_nodes_ptr;
3363 struct bitmask* os::Linux::_numa_interleave_bitmask;
3364 struct bitmask* os::Linux::_numa_membind_bitmask;
3365
3366 bool os::pd_uncommit_memory(char* addr, size_t size) {
3367 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3368 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3369 return res != (uintptr_t) MAP_FAILED;
3370 }
3371
3372 static address get_stack_commited_bottom(address bottom, size_t size) {
3373 address nbot = bottom;
3374 address ntop = bottom + size;
3375
3376 size_t page_sz = os::vm_page_size();
3377 unsigned pages = size / page_sz;
3378
3379 unsigned char vec[1];
3380 unsigned imin = 1, imax = pages + 1, imid;
3381 int mincore_return_value = 0;
3382
3383 assert(imin <= imax, "Unexpected page size");
3384
3385 while (imin < imax) {
3386 imid = (imax + imin) / 2;
3387 nbot = ntop - (imid * page_sz);
3388
3389 // Use a trick with mincore to check whether the page is mapped or not.
3390 // mincore sets vec to 1 if page resides in memory and to 0 if page
3391 // is swapped output but if page we are asking for is unmapped
3392 // it returns -1,ENOMEM
3393 mincore_return_value = mincore(nbot, page_sz, vec);
3394
3395 if (mincore_return_value == -1) {
3396 // Page is not mapped go up
3397 // to find first mapped page
3398 if (errno != EAGAIN) {
3399 assert(errno == ENOMEM, "Unexpected mincore errno");
3400 imax = imid;
3401 }
3402 } else {
3403 // Page is mapped go down
3404 // to find first not mapped page
3405 imin = imid + 1;
3406 }
3407 }
3408
3409 nbot = nbot + page_sz;
3410
3411 // Adjust stack bottom one page up if last checked page is not mapped
3412 if (mincore_return_value == -1) {
3413 nbot = nbot + page_sz;
3414 }
3415
3416 return nbot;
3417 }
3418
3419 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3420 int mincore_return_value;
3421 const size_t stripe = 1024; // query this many pages each time
3422 unsigned char vec[stripe + 1];
3423 // set a guard
3424 vec[stripe] = 'X';
3425
3426 const size_t page_sz = os::vm_page_size();
3427 size_t pages = size / page_sz;
3428
3429 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3430 assert(is_aligned(size, page_sz), "Size must be page aligned");
3431
3432 committed_start = NULL;
3433
3434 int loops = (pages + stripe - 1) / stripe;
3435 int committed_pages = 0;
3436 address loop_base = start;
3437 bool found_range = false;
3438
3439 for (int index = 0; index < loops && !found_range; index ++) {
3440 assert(pages > 0, "Nothing to do");
3441 int pages_to_query = (pages >= stripe) ? stripe : pages;
3442 pages -= pages_to_query;
3443
3444 // Get stable read
3445 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3446
3447 // During shutdown, some memory goes away without properly notifying NMT,
3448 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3449 // Bailout and return as not committed for now.
3450 if (mincore_return_value == -1 && errno == ENOMEM) {
3451 return false;
3452 }
3453
3454 assert(vec[stripe] == 'X', "overflow guard");
3455 assert(mincore_return_value == 0, "Range must be valid");
3456 // Process this stripe
3457 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3458 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3459 // End of current contiguous region
3460 if (committed_start != NULL) {
3461 found_range = true;
3462 break;
3463 }
3464 } else { // committed
3465 // Start of region
3466 if (committed_start == NULL) {
3467 committed_start = loop_base + page_sz * vecIdx;
3468 }
3469 committed_pages ++;
3470 }
3471 }
3472
3473 loop_base += pages_to_query * page_sz;
3474 }
3475
3476 if (committed_start != NULL) {
3477 assert(committed_pages > 0, "Must have committed region");
3478 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3479 assert(committed_start >= start && committed_start < start + size, "Out of range");
3480 committed_size = page_sz * committed_pages;
3481 return true;
3482 } else {
3483 assert(committed_pages == 0, "Should not have committed region");
3484 return false;
3485 }
3486 }
3487
3488
3489 // Linux uses a growable mapping for the stack, and if the mapping for
3490 // the stack guard pages is not removed when we detach a thread the
3491 // stack cannot grow beyond the pages where the stack guard was
3492 // mapped. If at some point later in the process the stack expands to
3493 // that point, the Linux kernel cannot expand the stack any further
3494 // because the guard pages are in the way, and a segfault occurs.
3495 //
3496 // However, it's essential not to split the stack region by unmapping
3497 // a region (leaving a hole) that's already part of the stack mapping,
3498 // so if the stack mapping has already grown beyond the guard pages at
3499 // the time we create them, we have to truncate the stack mapping.
3500 // So, we need to know the extent of the stack mapping when
3501 // create_stack_guard_pages() is called.
3502
3503 // We only need this for stacks that are growable: at the time of
3504 // writing thread stacks don't use growable mappings (i.e. those
3505 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3506 // only applies to the main thread.
3507
3508 // If the (growable) stack mapping already extends beyond the point
3509 // where we're going to put our guard pages, truncate the mapping at
3510 // that point by munmap()ping it. This ensures that when we later
3511 // munmap() the guard pages we don't leave a hole in the stack
3512 // mapping. This only affects the main/primordial thread
3513
3514 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3515 if (os::is_primordial_thread()) {
3516 // As we manually grow stack up to bottom inside create_attached_thread(),
3517 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3518 // we don't need to do anything special.
3519 // Check it first, before calling heavy function.
3520 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3521 unsigned char vec[1];
3522
3523 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3524 // Fallback to slow path on all errors, including EAGAIN
3525 stack_extent = (uintptr_t) get_stack_commited_bottom(
3526 os::Linux::initial_thread_stack_bottom(),
3527 (size_t)addr - stack_extent);
3528 }
3529
3530 if (stack_extent < (uintptr_t)addr) {
3531 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3532 }
3533 }
3534
3535 return os::commit_memory(addr, size, !ExecMem);
3536 }
3537
3538 // If this is a growable mapping, remove the guard pages entirely by
3539 // munmap()ping them. If not, just call uncommit_memory(). This only
3540 // affects the main/primordial thread, but guard against future OS changes.
3541 // It's safe to always unmap guard pages for primordial thread because we
3542 // always place it right after end of the mapped region.
3543
3544 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3545 uintptr_t stack_extent, stack_base;
3546
3547 if (os::is_primordial_thread()) {
3548 return ::munmap(addr, size) == 0;
3549 }
3550
3551 return os::uncommit_memory(addr, size);
3552 }
3553
3554 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3555 // at 'requested_addr'. If there are existing memory mappings at the same
3556 // location, however, they will be overwritten. If 'fixed' is false,
3557 // 'requested_addr' is only treated as a hint, the return value may or
3558 // may not start from the requested address. Unlike Linux mmap(), this
3559 // function returns NULL to indicate failure.
3560 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3561 char * addr;
3562 int flags;
3563
3564 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3565 if (fixed) {
3566 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3567 flags |= MAP_FIXED;
3568 }
3569
3570 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3571 // touch an uncommitted page. Otherwise, the read/write might
3572 // succeed if we have enough swap space to back the physical page.
3573 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3574 flags, -1, 0);
3575
3576 return addr == MAP_FAILED ? NULL : addr;
3577 }
3578
3579 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3580 // (req_addr != NULL) or with a given alignment.
3581 // - bytes shall be a multiple of alignment.
3582 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3583 // - alignment sets the alignment at which memory shall be allocated.
3584 // It must be a multiple of allocation granularity.
3585 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3586 // req_addr or NULL.
3587 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3588
3589 size_t extra_size = bytes;
3590 if (req_addr == NULL && alignment > 0) {
3591 extra_size += alignment;
3592 }
3593
3594 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3595 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3596 -1, 0);
3597 if (start == MAP_FAILED) {
3598 start = NULL;
3599 } else {
3600 if (req_addr != NULL) {
3601 if (start != req_addr) {
3602 ::munmap(start, extra_size);
3603 start = NULL;
3604 }
3605 } else {
3606 char* const start_aligned = align_up(start, alignment);
3607 char* const end_aligned = start_aligned + bytes;
3608 char* const end = start + extra_size;
3609 if (start_aligned > start) {
3610 ::munmap(start, start_aligned - start);
3611 }
3612 if (end_aligned < end) {
3613 ::munmap(end_aligned, end - end_aligned);
3614 }
3615 start = start_aligned;
3616 }
3617 }
3618 return start;
3619 }
3620
3621 static int anon_munmap(char * addr, size_t size) {
3622 return ::munmap(addr, size) == 0;
3623 }
3624
3625 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3626 size_t alignment_hint) {
3627 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3628 }
3629
3630 bool os::pd_release_memory(char* addr, size_t size) {
3631 return anon_munmap(addr, size);
3632 }
3633
3634 static bool linux_mprotect(char* addr, size_t size, int prot) {
3635 // Linux wants the mprotect address argument to be page aligned.
3636 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3637
3638 // According to SUSv3, mprotect() should only be used with mappings
3639 // established by mmap(), and mmap() always maps whole pages. Unaligned
3640 // 'addr' likely indicates problem in the VM (e.g. trying to change
3641 // protection of malloc'ed or statically allocated memory). Check the
3642 // caller if you hit this assert.
3643 assert(addr == bottom, "sanity check");
3644
3645 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3646 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3647 return ::mprotect(bottom, size, prot) == 0;
3648 }
3649
3650 // Set protections specified
3651 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3652 bool is_committed) {
3653 unsigned int p = 0;
3654 switch (prot) {
3655 case MEM_PROT_NONE: p = PROT_NONE; break;
3656 case MEM_PROT_READ: p = PROT_READ; break;
3657 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3658 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3659 default:
3660 ShouldNotReachHere();
3661 }
3662 // is_committed is unused.
3663 return linux_mprotect(addr, bytes, p);
3664 }
3665
3666 bool os::guard_memory(char* addr, size_t size) {
3667 return linux_mprotect(addr, size, PROT_NONE);
3668 }
3669
3670 bool os::unguard_memory(char* addr, size_t size) {
3671 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3672 }
3673
3674 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3675 size_t page_size) {
3676 bool result = false;
3677 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3678 MAP_ANONYMOUS|MAP_PRIVATE,
3679 -1, 0);
3680 if (p != MAP_FAILED) {
3681 void *aligned_p = align_up(p, page_size);
3682
3683 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3684
3685 munmap(p, page_size * 2);
3686 }
3687
3688 if (warn && !result) {
3689 warning("TransparentHugePages is not supported by the operating system.");
3690 }
3691
3692 return result;
3693 }
3694
3695 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3696 bool result = false;
3697 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3698 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3699 -1, 0);
3700
3701 if (p != MAP_FAILED) {
3702 // We don't know if this really is a huge page or not.
3703 FILE *fp = fopen("/proc/self/maps", "r");
3704 if (fp) {
3705 while (!feof(fp)) {
3706 char chars[257];
3707 long x = 0;
3708 if (fgets(chars, sizeof(chars), fp)) {
3709 if (sscanf(chars, "%lx-%*x", &x) == 1
3710 && x == (long)p) {
3711 if (strstr (chars, "hugepage")) {
3712 result = true;
3713 break;
3714 }
3715 }
3716 }
3717 }
3718 fclose(fp);
3719 }
3720 munmap(p, page_size);
3721 }
3722
3723 if (warn && !result) {
3724 warning("HugeTLBFS is not supported by the operating system.");
3725 }
3726
3727 return result;
3728 }
3729
3730 // From the coredump_filter documentation:
3731 //
3732 // - (bit 0) anonymous private memory
3733 // - (bit 1) anonymous shared memory
3734 // - (bit 2) file-backed private memory
3735 // - (bit 3) file-backed shared memory
3736 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3737 // effective only if the bit 2 is cleared)
3738 // - (bit 5) hugetlb private memory
3739 // - (bit 6) hugetlb shared memory
3740 // - (bit 7) dax private memory
3741 // - (bit 8) dax shared memory
3742 //
3743 static void set_coredump_filter(CoredumpFilterBit bit) {
3744 FILE *f;
3745 long cdm;
3746
3747 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3748 return;
3749 }
3750
3751 if (fscanf(f, "%lx", &cdm) != 1) {
3752 fclose(f);
3753 return;
3754 }
3755
3756 long saved_cdm = cdm;
3757 rewind(f);
3758 cdm |= bit;
3759
3760 if (cdm != saved_cdm) {
3761 fprintf(f, "%#lx", cdm);
3762 }
3763
3764 fclose(f);
3765 }
3766
3767 // Large page support
3768
3769 static size_t _large_page_size = 0;
3770
3771 size_t os::Linux::find_default_large_page_size() {
3772 if (_default_large_page_size != 0) {
3773 return _default_large_page_size;
3774 }
3775 size_t large_page_size = 0;
3776
3777 // large_page_size on Linux is used to round up heap size. x86 uses either
3778 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3779 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3780 // page as large as 256M.
3781 //
3782 // Here we try to figure out page size by parsing /proc/meminfo and looking
3783 // for a line with the following format:
3784 // Hugepagesize: 2048 kB
3785 //
3786 // If we can't determine the value (e.g. /proc is not mounted, or the text
3787 // format has been changed), we'll use the largest page size supported by
3788 // the processor.
3789
3790 #ifndef ZERO
3791 large_page_size =
3792 AARCH64_ONLY(2 * M)
3793 AMD64_ONLY(2 * M)
3794 ARM32_ONLY(2 * M)
3795 IA32_ONLY(4 * M)
3796 IA64_ONLY(256 * M)
3797 PPC_ONLY(4 * M)
3798 S390_ONLY(1 * M)
3799 SPARC_ONLY(4 * M);
3800 #endif // ZERO
3801
3802 FILE *fp = fopen("/proc/meminfo", "r");
3803 if (fp) {
3804 while (!feof(fp)) {
3805 int x = 0;
3806 char buf[16];
3807 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3808 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3809 large_page_size = x * K;
3810 break;
3811 }
3812 } else {
3813 // skip to next line
3814 for (;;) {
3815 int ch = fgetc(fp);
3816 if (ch == EOF || ch == (int)'\n') break;
3817 }
3818 }
3819 }
3820 fclose(fp);
3821 }
3822 return large_page_size;
3823 }
3824
3825 size_t os::Linux::find_large_page_size(size_t large_page_size) {
3826 if (_default_large_page_size == 0) {
3827 _default_large_page_size = Linux::find_default_large_page_size();
3828 }
3829 // We need to scan /sys/kernel/mm/hugepages
3830 // to discover the available page sizes
3831 const char* sys_hugepages = "/sys/kernel/mm/hugepages";
3832
3833 DIR *dir = opendir(sys_hugepages);
3834 if (dir == NULL) {
3835 return _default_large_page_size;
3836 }
3837
3838 struct dirent *entry;
3839 size_t page_size;
3840 while ((entry = readdir(dir)) != NULL) {
3841 if (entry->d_type == DT_DIR &&
3842 sscanf(entry->d_name, "hugepages-%zukB", &page_size) == 1) {
3843 // The kernel is using kB, hotspot uses bytes
3844 if (large_page_size == page_size * K) {
3845 closedir(dir);
3846 return large_page_size;
3847 }
3848 }
3849 }
3850 closedir(dir);
3851 return _default_large_page_size;
3852 }
3853
3854 size_t os::Linux::setup_large_page_size() {
3855 _default_large_page_size = Linux::find_default_large_page_size();
3856
3857 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != _default_large_page_size ) {
3858 _large_page_size = find_large_page_size(LargePageSizeInBytes);
3859 if (_large_page_size == _default_large_page_size) {
3860 warning("Setting LargePageSizeInBytes=" SIZE_FORMAT " has no effect on this OS. Using the default large page size "
3861 SIZE_FORMAT "%s.",
3862 LargePageSizeInBytes,
3863 byte_size_in_proper_unit(_large_page_size), proper_unit_for_byte_size(_large_page_size));
3864 }
3865 } else {
3866 _large_page_size = _default_large_page_size;
3867 }
3868
3869 const size_t default_page_size = (size_t)Linux::page_size();
3870 if (_large_page_size > default_page_size) {
3871 _page_sizes[0] = _large_page_size;
3872 _page_sizes[1] = default_page_size;
3873 _page_sizes[2] = 0;
3874 }
3875
3876 return _large_page_size;
3877 }
3878
3879 size_t os::Linux::default_large_page_size() {
3880 return _default_large_page_size;
3881 }
3882
3883 bool os::Linux::setup_large_page_type(size_t page_size) {
3884 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3885 FLAG_IS_DEFAULT(UseSHM) &&
3886 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3887
3888 // The type of large pages has not been specified by the user.
3889
3890 // Try UseHugeTLBFS and then UseSHM.
3891 UseHugeTLBFS = UseSHM = true;
3892
3893 // Don't try UseTransparentHugePages since there are known
3894 // performance issues with it turned on. This might change in the future.
3895 UseTransparentHugePages = false;
3896 }
3897
3898 if (UseTransparentHugePages) {
3899 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3900 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3901 UseHugeTLBFS = false;
3902 UseSHM = false;
3903 return true;
3904 }
3905 UseTransparentHugePages = false;
3906 }
3907
3908 if (UseHugeTLBFS) {
3909 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3910 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3911 UseSHM = false;
3912 return true;
3913 }
3914 UseHugeTLBFS = false;
3915 }
3916
3917 return UseSHM;
3918 }
3919
3920 void os::large_page_init() {
3921 if (!UseLargePages &&
3922 !UseTransparentHugePages &&
3923 !UseHugeTLBFS &&
3924 !UseSHM) {
3925 // Not using large pages.
3926 return;
3927 }
3928
3929 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3930 // The user explicitly turned off large pages.
3931 // Ignore the rest of the large pages flags.
3932 UseTransparentHugePages = false;
3933 UseHugeTLBFS = false;
3934 UseSHM = false;
3935 return;
3936 }
3937
3938 size_t large_page_size = Linux::setup_large_page_size();
3939 UseLargePages = Linux::setup_large_page_type(large_page_size);
3940
3941 set_coredump_filter(LARGEPAGES_BIT);
3942 }
3943
3944 #ifndef SHM_HUGETLB
3945 #define SHM_HUGETLB 04000
3946 #endif
3947
3948 #define shm_warning_format(format, ...) \
3949 do { \
3950 if (UseLargePages && \
3951 (!FLAG_IS_DEFAULT(UseLargePages) || \
3952 !FLAG_IS_DEFAULT(UseSHM) || \
3953 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3954 warning(format, __VA_ARGS__); \
3955 } \
3956 } while (0)
3957
3958 #define shm_warning(str) shm_warning_format("%s", str)
3959
3960 #define shm_warning_with_errno(str) \
3961 do { \
3962 int err = errno; \
3963 shm_warning_format(str " (error = %d)", err); \
3964 } while (0)
3965
3966 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3967 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3968
3969 if (!is_aligned(alignment, SHMLBA)) {
3970 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3971 return NULL;
3972 }
3973
3974 // To ensure that we get 'alignment' aligned memory from shmat,
3975 // we pre-reserve aligned virtual memory and then attach to that.
3976
3977 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3978 if (pre_reserved_addr == NULL) {
3979 // Couldn't pre-reserve aligned memory.
3980 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3981 return NULL;
3982 }
3983
3984 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3985 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3986
3987 if ((intptr_t)addr == -1) {
3988 int err = errno;
3989 shm_warning_with_errno("Failed to attach shared memory.");
3990
3991 assert(err != EACCES, "Unexpected error");
3992 assert(err != EIDRM, "Unexpected error");
3993 assert(err != EINVAL, "Unexpected error");
3994
3995 // Since we don't know if the kernel unmapped the pre-reserved memory area
3996 // we can't unmap it, since that would potentially unmap memory that was
3997 // mapped from other threads.
3998 return NULL;
3999 }
4000
4001 return addr;
4002 }
4003
4004 static char* shmat_at_address(int shmid, char* req_addr) {
4005 if (!is_aligned(req_addr, SHMLBA)) {
4006 assert(false, "Requested address needs to be SHMLBA aligned");
4007 return NULL;
4008 }
4009
4010 char* addr = (char*)shmat(shmid, req_addr, 0);
4011
4012 if ((intptr_t)addr == -1) {
4013 shm_warning_with_errno("Failed to attach shared memory.");
4014 return NULL;
4015 }
4016
4017 return addr;
4018 }
4019
4020 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
4021 // If a req_addr has been provided, we assume that the caller has already aligned the address.
4022 if (req_addr != NULL) {
4023 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
4024 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
4025 return shmat_at_address(shmid, req_addr);
4026 }
4027
4028 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
4029 // return large page size aligned memory addresses when req_addr == NULL.
4030 // However, if the alignment is larger than the large page size, we have
4031 // to manually ensure that the memory returned is 'alignment' aligned.
4032 if (alignment > os::large_page_size()) {
4033 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
4034 return shmat_with_alignment(shmid, bytes, alignment);
4035 } else {
4036 return shmat_at_address(shmid, NULL);
4037 }
4038 }
4039
4040 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
4041 char* req_addr, bool exec) {
4042 // "exec" is passed in but not used. Creating the shared image for
4043 // the code cache doesn't have an SHM_X executable permission to check.
4044 assert(UseLargePages && UseSHM, "only for SHM large pages");
4045 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4046 assert(is_aligned(req_addr, alignment), "Unaligned address");
4047
4048 if (!is_aligned(bytes, os::large_page_size())) {
4049 return NULL; // Fallback to small pages.
4050 }
4051
4052 // Create a large shared memory region to attach to based on size.
4053 // Currently, size is the total size of the heap.
4054 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
4055 if (shmid == -1) {
4056 // Possible reasons for shmget failure:
4057 // 1. shmmax is too small for Java heap.
4058 // > check shmmax value: cat /proc/sys/kernel/shmmax
4059 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
4060 // 2. not enough large page memory.
4061 // > check available large pages: cat /proc/meminfo
4062 // > increase amount of large pages:
4063 // echo new_value > /proc/sys/vm/nr_hugepages
4064 // Note 1: different Linux may use different name for this property,
4065 // e.g. on Redhat AS-3 it is "hugetlb_pool".
4066 // Note 2: it's possible there's enough physical memory available but
4067 // they are so fragmented after a long run that they can't
4068 // coalesce into large pages. Try to reserve large pages when
4069 // the system is still "fresh".
4070 shm_warning_with_errno("Failed to reserve shared memory.");
4071 return NULL;
4072 }
4073
4074 // Attach to the region.
4075 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
4076
4077 // Remove shmid. If shmat() is successful, the actual shared memory segment
4078 // will be deleted when it's detached by shmdt() or when the process
4079 // terminates. If shmat() is not successful this will remove the shared
4080 // segment immediately.
4081 shmctl(shmid, IPC_RMID, NULL);
4082
4083 return addr;
4084 }
4085
4086 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
4087 int error) {
4088 assert(error == ENOMEM, "Only expect to fail if no memory is available");
4089
4090 bool warn_on_failure = UseLargePages &&
4091 (!FLAG_IS_DEFAULT(UseLargePages) ||
4092 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
4093 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
4094
4095 if (warn_on_failure) {
4096 char msg[128];
4097 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
4098 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
4099 warning("%s", msg);
4100 }
4101 }
4102
4103 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
4104 char* req_addr,
4105 bool exec) {
4106 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4107 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
4108 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4109
4110 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4111 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB;
4112
4113 if (os::large_page_size() != default_large_page_size()) {
4114 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT);
4115 }
4116 char* addr = (char*)::mmap(req_addr, bytes, prot, flags, -1, 0);
4117
4118 if (addr == MAP_FAILED) {
4119 warn_on_large_pages_failure(req_addr, bytes, errno);
4120 return NULL;
4121 }
4122
4123 assert(is_aligned(addr, os::large_page_size()), "Must be");
4124
4125 return addr;
4126 }
4127
4128 // Reserve memory using mmap(MAP_HUGETLB).
4129 // - bytes shall be a multiple of alignment.
4130 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
4131 // - alignment sets the alignment at which memory shall be allocated.
4132 // It must be a multiple of allocation granularity.
4133 // Returns address of memory or NULL. If req_addr was not NULL, will only return
4134 // req_addr or NULL.
4135 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
4136 size_t alignment,
4137 char* req_addr,
4138 bool exec) {
4139 size_t large_page_size = os::large_page_size();
4140 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
4141
4142 assert(is_aligned(req_addr, alignment), "Must be");
4143 assert(is_aligned(bytes, alignment), "Must be");
4144
4145 // First reserve - but not commit - the address range in small pages.
4146 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
4147
4148 if (start == NULL) {
4149 return NULL;
4150 }
4151
4152 assert(is_aligned(start, alignment), "Must be");
4153
4154 char* end = start + bytes;
4155
4156 // Find the regions of the allocated chunk that can be promoted to large pages.
4157 char* lp_start = align_up(start, large_page_size);
4158 char* lp_end = align_down(end, large_page_size);
4159
4160 size_t lp_bytes = lp_end - lp_start;
4161
4162 assert(is_aligned(lp_bytes, large_page_size), "Must be");
4163
4164 if (lp_bytes == 0) {
4165 // The mapped region doesn't even span the start and the end of a large page.
4166 // Fall back to allocate a non-special area.
4167 ::munmap(start, end - start);
4168 return NULL;
4169 }
4170
4171 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4172 int flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED;
4173 void* result;
4174
4175 // Commit small-paged leading area.
4176 if (start != lp_start) {
4177 result = ::mmap(start, lp_start - start, prot, flags, -1, 0);
4178 if (result == MAP_FAILED) {
4179 ::munmap(lp_start, end - lp_start);
4180 return NULL;
4181 }
4182 }
4183
4184 // Commit large-paged area.
4185 flags |= MAP_HUGETLB;
4186
4187 if (os::large_page_size() != default_large_page_size()) {
4188 flags |= (exact_log2(os::large_page_size()) << MAP_HUGE_SHIFT);
4189 }
4190
4191 result = ::mmap(lp_start, lp_bytes, prot, flags, -1, 0);
4192 if (result == MAP_FAILED) {
4193 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
4194 // If the mmap above fails, the large pages region will be unmapped and we
4195 // have regions before and after with small pages. Release these regions.
4196 //
4197 // | mapped | unmapped | mapped |
4198 // ^ ^ ^ ^
4199 // start lp_start lp_end end
4200 //
4201 ::munmap(start, lp_start - start);
4202 ::munmap(lp_end, end - lp_end);
4203 return NULL;
4204 }
4205
4206 // Commit small-paged trailing area.
4207 if (lp_end != end) {
4208 result = ::mmap(lp_end, end - lp_end, prot,
4209 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4210 -1, 0);
4211 if (result == MAP_FAILED) {
4212 ::munmap(start, lp_end - start);
4213 return NULL;
4214 }
4215 }
4216
4217 return start;
4218 }
4219
4220 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4221 size_t alignment,
4222 char* req_addr,
4223 bool exec) {
4224 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4225 assert(is_aligned(req_addr, alignment), "Must be");
4226 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4227 assert(is_power_of_2(os::large_page_size()), "Must be");
4228 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
4229
4230 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
4231 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
4232 } else {
4233 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
4234 }
4235 }
4236
4237 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment,
4238 char* req_addr, bool exec) {
4239 assert(UseLargePages, "only for large pages");
4240
4241 char* addr;
4242 if (UseSHM) {
4243 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4244 } else {
4245 assert(UseHugeTLBFS, "must be");
4246 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4247 }
4248
4249 if (addr != NULL) {
4250 if (UseNUMAInterleaving) {
4251 numa_make_global(addr, bytes);
4252 }
4253 }
4254
4255 return addr;
4256 }
4257
4258 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4259 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4260 return shmdt(base) == 0;
4261 }
4262
4263 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4264 return pd_release_memory(base, bytes);
4265 }
4266
4267 bool os::pd_release_memory_special(char* base, size_t bytes) {
4268 assert(UseLargePages, "only for large pages");
4269 bool res;
4270
4271 if (UseSHM) {
4272 res = os::Linux::release_memory_special_shm(base, bytes);
4273 } else {
4274 assert(UseHugeTLBFS, "must be");
4275 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4276 }
4277 return res;
4278 }
4279
4280 size_t os::large_page_size() {
4281 return _large_page_size;
4282 }
4283
4284 // With SysV SHM the entire memory region must be allocated as shared
4285 // memory.
4286 // HugeTLBFS allows application to commit large page memory on demand.
4287 // However, when committing memory with HugeTLBFS fails, the region
4288 // that was supposed to be committed will lose the old reservation
4289 // and allow other threads to steal that memory region. Because of this
4290 // behavior we can't commit HugeTLBFS memory.
4291 bool os::can_commit_large_page_memory() {
4292 return UseTransparentHugePages;
4293 }
4294
4295 bool os::can_execute_large_page_memory() {
4296 return UseTransparentHugePages || UseHugeTLBFS;
4297 }
4298
4299 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4300 assert(file_desc >= 0, "file_desc is not valid");
4301 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4302 if (result != NULL) {
4303 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4304 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4305 }
4306 }
4307 return result;
4308 }
4309
4310 // Reserve memory at an arbitrary address, only if that area is
4311 // available (and not reserved for something else).
4312
4313 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4314 // Assert only that the size is a multiple of the page size, since
4315 // that's all that mmap requires, and since that's all we really know
4316 // about at this low abstraction level. If we need higher alignment,
4317 // we can either pass an alignment to this method or verify alignment
4318 // in one of the methods further up the call chain. See bug 5044738.
4319 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4320
4321 // Repeatedly allocate blocks until the block is allocated at the
4322 // right spot.
4323
4324 // Linux mmap allows caller to pass an address as hint; give it a try first,
4325 // if kernel honors the hint then we can return immediately.
4326 char * addr = anon_mmap(requested_addr, bytes, false);
4327 if (addr == requested_addr) {
4328 return requested_addr;
4329 }
4330
4331 if (addr != NULL) {
4332 // mmap() is successful but it fails to reserve at the requested address
4333 anon_munmap(addr, bytes);
4334 }
4335
4336 return NULL;
4337 }
4338
4339 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4340 void os::infinite_sleep() {
4341 while (true) { // sleep forever ...
4342 ::sleep(100); // ... 100 seconds at a time
4343 }
4344 }
4345
4346 // Used to convert frequent JVM_Yield() to nops
4347 bool os::dont_yield() {
4348 return DontYieldALot;
4349 }
4350
4351 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4352 // actually give up the CPU. Since skip buddy (v2.6.28):
4353 //
4354 // * Sets the yielding task as skip buddy for current CPU's run queue.
4355 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4356 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4357 //
4358 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4359 // getting re-scheduled immediately.
4360 //
4361 void os::naked_yield() {
4362 sched_yield();
4363 }
4364
4365 ////////////////////////////////////////////////////////////////////////////////
4366 // thread priority support
4367
4368 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4369 // only supports dynamic priority, static priority must be zero. For real-time
4370 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4371 // However, for large multi-threaded applications, SCHED_RR is not only slower
4372 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4373 // of 5 runs - Sep 2005).
4374 //
4375 // The following code actually changes the niceness of kernel-thread/LWP. It
4376 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4377 // not the entire user process, and user level threads are 1:1 mapped to kernel
4378 // threads. It has always been the case, but could change in the future. For
4379 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4380 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4381 // (e.g., root privilege or CAP_SYS_NICE capability).
4382
4383 int os::java_to_os_priority[CriticalPriority + 1] = {
4384 19, // 0 Entry should never be used
4385
4386 4, // 1 MinPriority
4387 3, // 2
4388 2, // 3
4389
4390 1, // 4
4391 0, // 5 NormPriority
4392 -1, // 6
4393
4394 -2, // 7
4395 -3, // 8
4396 -4, // 9 NearMaxPriority
4397
4398 -5, // 10 MaxPriority
4399
4400 -5 // 11 CriticalPriority
4401 };
4402
4403 static int prio_init() {
4404 if (ThreadPriorityPolicy == 1) {
4405 if (geteuid() != 0) {
4406 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) {
4407 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4408 "e.g., being the root user. If the necessary permission is not " \
4409 "possessed, changes to priority will be silently ignored.");
4410 }
4411 }
4412 }
4413 if (UseCriticalJavaThreadPriority) {
4414 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4415 }
4416 return 0;
4417 }
4418
4419 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4420 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4421
4422 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4423 return (ret == 0) ? OS_OK : OS_ERR;
4424 }
4425
4426 OSReturn os::get_native_priority(const Thread* const thread,
4427 int *priority_ptr) {
4428 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4429 *priority_ptr = java_to_os_priority[NormPriority];
4430 return OS_OK;
4431 }
4432
4433 errno = 0;
4434 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4435 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4436 }
4437
4438 ////////////////////////////////////////////////////////////////////////////////
4439 // suspend/resume support
4440
4441 // The low-level signal-based suspend/resume support is a remnant from the
4442 // old VM-suspension that used to be for java-suspension, safepoints etc,
4443 // within hotspot. Currently used by JFR's OSThreadSampler
4444 //
4445 // The remaining code is greatly simplified from the more general suspension
4446 // code that used to be used.
4447 //
4448 // The protocol is quite simple:
4449 // - suspend:
4450 // - sends a signal to the target thread
4451 // - polls the suspend state of the osthread using a yield loop
4452 // - target thread signal handler (SR_handler) sets suspend state
4453 // and blocks in sigsuspend until continued
4454 // - resume:
4455 // - sets target osthread state to continue
4456 // - sends signal to end the sigsuspend loop in the SR_handler
4457 //
4458 // Note that the SR_lock plays no role in this suspend/resume protocol,
4459 // but is checked for NULL in SR_handler as a thread termination indicator.
4460 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4461 //
4462 // Note that resume_clear_context() and suspend_save_context() are needed
4463 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4464 // which in part is used by:
4465 // - Forte Analyzer: AsyncGetCallTrace()
4466 // - StackBanging: get_frame_at_stack_banging_point()
4467
4468 static void resume_clear_context(OSThread *osthread) {
4469 osthread->set_ucontext(NULL);
4470 osthread->set_siginfo(NULL);
4471 }
4472
4473 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4474 ucontext_t* context) {
4475 osthread->set_ucontext(context);
4476 osthread->set_siginfo(siginfo);
4477 }
4478
4479 // Handler function invoked when a thread's execution is suspended or
4480 // resumed. We have to be careful that only async-safe functions are
4481 // called here (Note: most pthread functions are not async safe and
4482 // should be avoided.)
4483 //
4484 // Note: sigwait() is a more natural fit than sigsuspend() from an
4485 // interface point of view, but sigwait() prevents the signal hander
4486 // from being run. libpthread would get very confused by not having
4487 // its signal handlers run and prevents sigwait()'s use with the
4488 // mutex granting granting signal.
4489 //
4490 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4491 //
4492 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4493 // Save and restore errno to avoid confusing native code with EINTR
4494 // after sigsuspend.
4495 int old_errno = errno;
4496
4497 Thread* thread = Thread::current_or_null_safe();
4498 assert(thread != NULL, "Missing current thread in SR_handler");
4499
4500 // On some systems we have seen signal delivery get "stuck" until the signal
4501 // mask is changed as part of thread termination. Check that the current thread
4502 // has not already terminated (via SR_lock()) - else the following assertion
4503 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4504 // destructor has completed.
4505
4506 if (thread->SR_lock() == NULL) {
4507 return;
4508 }
4509
4510 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4511
4512 OSThread* osthread = thread->osthread();
4513
4514 os::SuspendResume::State current = osthread->sr.state();
4515 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4516 suspend_save_context(osthread, siginfo, context);
4517
4518 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4519 os::SuspendResume::State state = osthread->sr.suspended();
4520 if (state == os::SuspendResume::SR_SUSPENDED) {
4521 sigset_t suspend_set; // signals for sigsuspend()
4522 sigemptyset(&suspend_set);
4523 // get current set of blocked signals and unblock resume signal
4524 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4525 sigdelset(&suspend_set, SR_signum);
4526
4527 sr_semaphore.signal();
4528 // wait here until we are resumed
4529 while (1) {
4530 sigsuspend(&suspend_set);
4531
4532 os::SuspendResume::State result = osthread->sr.running();
4533 if (result == os::SuspendResume::SR_RUNNING) {
4534 sr_semaphore.signal();
4535 break;
4536 }
4537 }
4538
4539 } else if (state == os::SuspendResume::SR_RUNNING) {
4540 // request was cancelled, continue
4541 } else {
4542 ShouldNotReachHere();
4543 }
4544
4545 resume_clear_context(osthread);
4546 } else if (current == os::SuspendResume::SR_RUNNING) {
4547 // request was cancelled, continue
4548 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4549 // ignore
4550 } else {
4551 // ignore
4552 }
4553
4554 errno = old_errno;
4555 }
4556
4557 static int SR_initialize() {
4558 struct sigaction act;
4559 char *s;
4560
4561 // Get signal number to use for suspend/resume
4562 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4563 int sig = ::strtol(s, 0, 10);
4564 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4565 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4566 SR_signum = sig;
4567 } else {
4568 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4569 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4570 }
4571 }
4572
4573 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4574 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4575
4576 sigemptyset(&SR_sigset);
4577 sigaddset(&SR_sigset, SR_signum);
4578
4579 // Set up signal handler for suspend/resume
4580 act.sa_flags = SA_RESTART|SA_SIGINFO;
4581 act.sa_handler = (void (*)(int)) SR_handler;
4582
4583 // SR_signum is blocked by default.
4584 // 4528190 - We also need to block pthread restart signal (32 on all
4585 // supported Linux platforms). Note that LinuxThreads need to block
4586 // this signal for all threads to work properly. So we don't have
4587 // to use hard-coded signal number when setting up the mask.
4588 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4589
4590 if (sigaction(SR_signum, &act, 0) == -1) {
4591 return -1;
4592 }
4593
4594 // Save signal flag
4595 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4596 return 0;
4597 }
4598
4599 static int sr_notify(OSThread* osthread) {
4600 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4601 assert_status(status == 0, status, "pthread_kill");
4602 return status;
4603 }
4604
4605 // "Randomly" selected value for how long we want to spin
4606 // before bailing out on suspending a thread, also how often
4607 // we send a signal to a thread we want to resume
4608 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4609 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4610
4611 // returns true on success and false on error - really an error is fatal
4612 // but this seems the normal response to library errors
4613 static bool do_suspend(OSThread* osthread) {
4614 assert(osthread->sr.is_running(), "thread should be running");
4615 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4616
4617 // mark as suspended and send signal
4618 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4619 // failed to switch, state wasn't running?
4620 ShouldNotReachHere();
4621 return false;
4622 }
4623
4624 if (sr_notify(osthread) != 0) {
4625 ShouldNotReachHere();
4626 }
4627
4628 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4629 while (true) {
4630 if (sr_semaphore.timedwait(2)) {
4631 break;
4632 } else {
4633 // timeout
4634 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4635 if (cancelled == os::SuspendResume::SR_RUNNING) {
4636 return false;
4637 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4638 // make sure that we consume the signal on the semaphore as well
4639 sr_semaphore.wait();
4640 break;
4641 } else {
4642 ShouldNotReachHere();
4643 return false;
4644 }
4645 }
4646 }
4647
4648 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4649 return true;
4650 }
4651
4652 static void do_resume(OSThread* osthread) {
4653 assert(osthread->sr.is_suspended(), "thread should be suspended");
4654 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4655
4656 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4657 // failed to switch to WAKEUP_REQUEST
4658 ShouldNotReachHere();
4659 return;
4660 }
4661
4662 while (true) {
4663 if (sr_notify(osthread) == 0) {
4664 if (sr_semaphore.timedwait(2)) {
4665 if (osthread->sr.is_running()) {
4666 return;
4667 }
4668 }
4669 } else {
4670 ShouldNotReachHere();
4671 }
4672 }
4673
4674 guarantee(osthread->sr.is_running(), "Must be running!");
4675 }
4676
4677 ///////////////////////////////////////////////////////////////////////////////////
4678 // signal handling (except suspend/resume)
4679
4680 // This routine may be used by user applications as a "hook" to catch signals.
4681 // The user-defined signal handler must pass unrecognized signals to this
4682 // routine, and if it returns true (non-zero), then the signal handler must
4683 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4684 // routine will never retun false (zero), but instead will execute a VM panic
4685 // routine kill the process.
4686 //
4687 // If this routine returns false, it is OK to call it again. This allows
4688 // the user-defined signal handler to perform checks either before or after
4689 // the VM performs its own checks. Naturally, the user code would be making
4690 // a serious error if it tried to handle an exception (such as a null check
4691 // or breakpoint) that the VM was generating for its own correct operation.
4692 //
4693 // This routine may recognize any of the following kinds of signals:
4694 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4695 // It should be consulted by handlers for any of those signals.
4696 //
4697 // The caller of this routine must pass in the three arguments supplied
4698 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4699 // field of the structure passed to sigaction(). This routine assumes that
4700 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4701 //
4702 // Note that the VM will print warnings if it detects conflicting signal
4703 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4704 //
4705 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4706 siginfo_t* siginfo,
4707 void* ucontext,
4708 int abort_if_unrecognized);
4709
4710 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4711 assert(info != NULL && uc != NULL, "it must be old kernel");
4712 int orig_errno = errno; // Preserve errno value over signal handler.
4713 JVM_handle_linux_signal(sig, info, uc, true);
4714 errno = orig_errno;
4715 }
4716
4717
4718 // This boolean allows users to forward their own non-matching signals
4719 // to JVM_handle_linux_signal, harmlessly.
4720 bool os::Linux::signal_handlers_are_installed = false;
4721
4722 // For signal-chaining
4723 bool os::Linux::libjsig_is_loaded = false;
4724 typedef struct sigaction *(*get_signal_t)(int);
4725 get_signal_t os::Linux::get_signal_action = NULL;
4726
4727 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4728 struct sigaction *actp = NULL;
4729
4730 if (libjsig_is_loaded) {
4731 // Retrieve the old signal handler from libjsig
4732 actp = (*get_signal_action)(sig);
4733 }
4734 if (actp == NULL) {
4735 // Retrieve the preinstalled signal handler from jvm
4736 actp = os::Posix::get_preinstalled_handler(sig);
4737 }
4738
4739 return actp;
4740 }
4741
4742 static bool call_chained_handler(struct sigaction *actp, int sig,
4743 siginfo_t *siginfo, void *context) {
4744 // Call the old signal handler
4745 if (actp->sa_handler == SIG_DFL) {
4746 // It's more reasonable to let jvm treat it as an unexpected exception
4747 // instead of taking the default action.
4748 return false;
4749 } else if (actp->sa_handler != SIG_IGN) {
4750 if ((actp->sa_flags & SA_NODEFER) == 0) {
4751 // automaticlly block the signal
4752 sigaddset(&(actp->sa_mask), sig);
4753 }
4754
4755 sa_handler_t hand = NULL;
4756 sa_sigaction_t sa = NULL;
4757 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4758 // retrieve the chained handler
4759 if (siginfo_flag_set) {
4760 sa = actp->sa_sigaction;
4761 } else {
4762 hand = actp->sa_handler;
4763 }
4764
4765 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4766 actp->sa_handler = SIG_DFL;
4767 }
4768
4769 // try to honor the signal mask
4770 sigset_t oset;
4771 sigemptyset(&oset);
4772 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4773
4774 // call into the chained handler
4775 if (siginfo_flag_set) {
4776 (*sa)(sig, siginfo, context);
4777 } else {
4778 (*hand)(sig);
4779 }
4780
4781 // restore the signal mask
4782 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4783 }
4784 // Tell jvm's signal handler the signal is taken care of.
4785 return true;
4786 }
4787
4788 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4789 bool chained = false;
4790 // signal-chaining
4791 if (UseSignalChaining) {
4792 struct sigaction *actp = get_chained_signal_action(sig);
4793 if (actp != NULL) {
4794 chained = call_chained_handler(actp, sig, siginfo, context);
4795 }
4796 }
4797 return chained;
4798 }
4799
4800 // for diagnostic
4801 int sigflags[NSIG];
4802
4803 int os::Linux::get_our_sigflags(int sig) {
4804 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4805 return sigflags[sig];
4806 }
4807
4808 void os::Linux::set_our_sigflags(int sig, int flags) {
4809 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4810 if (sig > 0 && sig < NSIG) {
4811 sigflags[sig] = flags;
4812 }
4813 }
4814
4815 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4816 // Check for overwrite.
4817 struct sigaction oldAct;
4818 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4819
4820 void* oldhand = oldAct.sa_sigaction
4821 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4822 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4823 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4824 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4825 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4826 if (AllowUserSignalHandlers || !set_installed) {
4827 // Do not overwrite; user takes responsibility to forward to us.
4828 return;
4829 } else if (UseSignalChaining) {
4830 // save the old handler in jvm
4831 os::Posix::save_preinstalled_handler(sig, oldAct);
4832 // libjsig also interposes the sigaction() call below and saves the
4833 // old sigaction on it own.
4834 } else {
4835 fatal("Encountered unexpected pre-existing sigaction handler "
4836 "%#lx for signal %d.", (long)oldhand, sig);
4837 }
4838 }
4839
4840 struct sigaction sigAct;
4841 sigfillset(&(sigAct.sa_mask));
4842 sigAct.sa_handler = SIG_DFL;
4843 if (!set_installed) {
4844 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4845 } else {
4846 sigAct.sa_sigaction = signalHandler;
4847 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4848 }
4849 // Save flags, which are set by ours
4850 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4851 sigflags[sig] = sigAct.sa_flags;
4852
4853 int ret = sigaction(sig, &sigAct, &oldAct);
4854 assert(ret == 0, "check");
4855
4856 void* oldhand2 = oldAct.sa_sigaction
4857 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4858 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4859 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4860 }
4861
4862 // install signal handlers for signals that HotSpot needs to
4863 // handle in order to support Java-level exception handling.
4864
4865 void os::Linux::install_signal_handlers() {
4866 if (!signal_handlers_are_installed) {
4867 signal_handlers_are_installed = true;
4868
4869 // signal-chaining
4870 typedef void (*signal_setting_t)();
4871 signal_setting_t begin_signal_setting = NULL;
4872 signal_setting_t end_signal_setting = NULL;
4873 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4874 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4875 if (begin_signal_setting != NULL) {
4876 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4877 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4878 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4879 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4880 libjsig_is_loaded = true;
4881 assert(UseSignalChaining, "should enable signal-chaining");
4882 }
4883 if (libjsig_is_loaded) {
4884 // Tell libjsig jvm is setting signal handlers
4885 (*begin_signal_setting)();
4886 }
4887
4888 set_signal_handler(SIGSEGV, true);
4889 set_signal_handler(SIGPIPE, true);
4890 set_signal_handler(SIGBUS, true);
4891 set_signal_handler(SIGILL, true);
4892 set_signal_handler(SIGFPE, true);
4893 #if defined(PPC64)
4894 set_signal_handler(SIGTRAP, true);
4895 #endif
4896 set_signal_handler(SIGXFSZ, true);
4897
4898 if (libjsig_is_loaded) {
4899 // Tell libjsig jvm finishes setting signal handlers
4900 (*end_signal_setting)();
4901 }
4902
4903 // We don't activate signal checker if libjsig is in place, we trust ourselves
4904 // and if UserSignalHandler is installed all bets are off.
4905 // Log that signal checking is off only if -verbose:jni is specified.
4906 if (CheckJNICalls) {
4907 if (libjsig_is_loaded) {
4908 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
4909 check_signals = false;
4910 }
4911 if (AllowUserSignalHandlers) {
4912 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4913 check_signals = false;
4914 }
4915 }
4916 }
4917 }
4918
4919 // This is the fastest way to get thread cpu time on Linux.
4920 // Returns cpu time (user+sys) for any thread, not only for current.
4921 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4922 // It might work on 2.6.10+ with a special kernel/glibc patch.
4923 // For reference, please, see IEEE Std 1003.1-2004:
4924 // http://www.unix.org/single_unix_specification
4925
4926 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4927 struct timespec tp;
4928 int rc = os::Posix::clock_gettime(clockid, &tp);
4929 assert(rc == 0, "clock_gettime is expected to return 0 code");
4930
4931 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4932 }
4933
4934 /////
4935 // glibc on Linux platform uses non-documented flag
4936 // to indicate, that some special sort of signal
4937 // trampoline is used.
4938 // We will never set this flag, and we should
4939 // ignore this flag in our diagnostic
4940 #ifdef SIGNIFICANT_SIGNAL_MASK
4941 #undef SIGNIFICANT_SIGNAL_MASK
4942 #endif
4943 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4944
4945 static const char* get_signal_handler_name(address handler,
4946 char* buf, int buflen) {
4947 int offset = 0;
4948 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4949 if (found) {
4950 // skip directory names
4951 const char *p1, *p2;
4952 p1 = buf;
4953 size_t len = strlen(os::file_separator());
4954 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4955 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4956 } else {
4957 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4958 }
4959 return buf;
4960 }
4961
4962 static void print_signal_handler(outputStream* st, int sig,
4963 char* buf, size_t buflen) {
4964 struct sigaction sa;
4965
4966 sigaction(sig, NULL, &sa);
4967
4968 // See comment for SIGNIFICANT_SIGNAL_MASK define
4969 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4970
4971 st->print("%s: ", os::exception_name(sig, buf, buflen));
4972
4973 address handler = (sa.sa_flags & SA_SIGINFO)
4974 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4975 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4976
4977 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4978 st->print("SIG_DFL");
4979 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4980 st->print("SIG_IGN");
4981 } else {
4982 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4983 }
4984
4985 st->print(", sa_mask[0]=");
4986 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4987
4988 address rh = VMError::get_resetted_sighandler(sig);
4989 // May be, handler was resetted by VMError?
4990 if (rh != NULL) {
4991 handler = rh;
4992 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4993 }
4994
4995 st->print(", sa_flags=");
4996 os::Posix::print_sa_flags(st, sa.sa_flags);
4997
4998 // Check: is it our handler?
4999 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
5000 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
5001 // It is our signal handler
5002 // check for flags, reset system-used one!
5003 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
5004 st->print(
5005 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
5006 os::Linux::get_our_sigflags(sig));
5007 }
5008 }
5009 st->cr();
5010 }
5011
5012
5013 #define DO_SIGNAL_CHECK(sig) \
5014 do { \
5015 if (!sigismember(&check_signal_done, sig)) { \
5016 os::Linux::check_signal_handler(sig); \
5017 } \
5018 } while (0)
5019
5020 // This method is a periodic task to check for misbehaving JNI applications
5021 // under CheckJNI, we can add any periodic checks here
5022
5023 void os::run_periodic_checks() {
5024 if (check_signals == false) return;
5025
5026 // SEGV and BUS if overridden could potentially prevent
5027 // generation of hs*.log in the event of a crash, debugging
5028 // such a case can be very challenging, so we absolutely
5029 // check the following for a good measure:
5030 DO_SIGNAL_CHECK(SIGSEGV);
5031 DO_SIGNAL_CHECK(SIGILL);
5032 DO_SIGNAL_CHECK(SIGFPE);
5033 DO_SIGNAL_CHECK(SIGBUS);
5034 DO_SIGNAL_CHECK(SIGPIPE);
5035 DO_SIGNAL_CHECK(SIGXFSZ);
5036 #if defined(PPC64)
5037 DO_SIGNAL_CHECK(SIGTRAP);
5038 #endif
5039
5040 // ReduceSignalUsage allows the user to override these handlers
5041 // see comments at the very top and jvm_md.h
5042 if (!ReduceSignalUsage) {
5043 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
5044 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
5045 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
5046 DO_SIGNAL_CHECK(BREAK_SIGNAL);
5047 }
5048
5049 DO_SIGNAL_CHECK(SR_signum);
5050 }
5051
5052 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
5053
5054 static os_sigaction_t os_sigaction = NULL;
5055
5056 void os::Linux::check_signal_handler(int sig) {
5057 char buf[O_BUFLEN];
5058 address jvmHandler = NULL;
5059
5060
5061 struct sigaction act;
5062 if (os_sigaction == NULL) {
5063 // only trust the default sigaction, in case it has been interposed
5064 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
5065 if (os_sigaction == NULL) return;
5066 }
5067
5068 os_sigaction(sig, (struct sigaction*)NULL, &act);
5069
5070
5071 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
5072
5073 address thisHandler = (act.sa_flags & SA_SIGINFO)
5074 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
5075 : CAST_FROM_FN_PTR(address, act.sa_handler);
5076
5077
5078 switch (sig) {
5079 case SIGSEGV:
5080 case SIGBUS:
5081 case SIGFPE:
5082 case SIGPIPE:
5083 case SIGILL:
5084 case SIGXFSZ:
5085 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
5086 break;
5087
5088 case SHUTDOWN1_SIGNAL:
5089 case SHUTDOWN2_SIGNAL:
5090 case SHUTDOWN3_SIGNAL:
5091 case BREAK_SIGNAL:
5092 jvmHandler = (address)user_handler();
5093 break;
5094
5095 default:
5096 if (sig == SR_signum) {
5097 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
5098 } else {
5099 return;
5100 }
5101 break;
5102 }
5103
5104 if (thisHandler != jvmHandler) {
5105 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
5106 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
5107 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
5108 // No need to check this sig any longer
5109 sigaddset(&check_signal_done, sig);
5110 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
5111 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5112 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5113 exception_name(sig, buf, O_BUFLEN));
5114 }
5115 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5116 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5117 tty->print("expected:");
5118 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
5119 tty->cr();
5120 tty->print(" found:");
5121 os::Posix::print_sa_flags(tty, act.sa_flags);
5122 tty->cr();
5123 // No need to check this sig any longer
5124 sigaddset(&check_signal_done, sig);
5125 }
5126
5127 // Dump all the signal
5128 if (sigismember(&check_signal_done, sig)) {
5129 print_signal_handlers(tty, buf, O_BUFLEN);
5130 }
5131 }
5132
5133 extern void report_error(char* file_name, int line_no, char* title,
5134 char* format, ...);
5135
5136 // this is called _before_ most of the global arguments have been parsed
5137 void os::init(void) {
5138 char dummy; // used to get a guess on initial stack address
5139
5140 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5141
5142 init_random(1234567);
5143
5144 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5145 if (Linux::page_size() == -1) {
5146 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5147 os::strerror(errno));
5148 }
5149 init_page_sizes((size_t) Linux::page_size());
5150
5151 Linux::initialize_system_info();
5152
5153 os::Linux::CPUPerfTicks pticks;
5154 bool res = os::Linux::get_tick_information(&pticks, -1);
5155
5156 if (res && pticks.has_steal_ticks) {
5157 has_initial_tick_info = true;
5158 initial_total_ticks = pticks.total;
5159 initial_steal_ticks = pticks.steal;
5160 }
5161
5162 // _main_thread points to the thread that created/loaded the JVM.
5163 Linux::_main_thread = pthread_self();
5164
5165 // retrieve entry point for pthread_setname_np
5166 Linux::_pthread_setname_np =
5167 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5168
5169 os::Posix::init();
5170
5171 initial_time_count = javaTimeNanos();
5172
5173 // Always warn if no monotonic clock available
5174 if (!os::Posix::supports_monotonic_clock()) {
5175 warning("No monotonic clock was available - timed services may " \
5176 "be adversely affected if the time-of-day clock changes");
5177 }
5178 }
5179
5180 // To install functions for atexit system call
5181 extern "C" {
5182 static void perfMemory_exit_helper() {
5183 perfMemory_exit();
5184 }
5185 }
5186
5187 void os::pd_init_container_support() {
5188 OSContainer::init();
5189 }
5190
5191 void os::Linux::numa_init() {
5192
5193 // Java can be invoked as
5194 // 1. Without numactl and heap will be allocated/configured on all nodes as
5195 // per the system policy.
5196 // 2. With numactl --interleave:
5197 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5198 // API for membind case bitmask is reset.
5199 // Interleave is only hint and Kernel can fallback to other nodes if
5200 // no memory is available on the target nodes.
5201 // 3. With numactl --membind:
5202 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5203 // interleave case returns bitmask of all nodes.
5204 // numa_all_nodes_ptr holds bitmask of all nodes.
5205 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5206 // bitmask when externally configured to run on all or fewer nodes.
5207
5208 if (!Linux::libnuma_init()) {
5209 FLAG_SET_ERGO(UseNUMA, false);
5210 FLAG_SET_ERGO(UseNUMAInterleaving, false); // Also depends on libnuma.
5211 } else {
5212 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5213 // If there's only one node (they start from 0) or if the process
5214 // is bound explicitly to a single node using membind, disable NUMA unless
5215 // user explicilty forces NUMA optimizations on single-node/UMA systems
5216 UseNUMA = ForceNUMA;
5217 } else {
5218
5219 LogTarget(Info,os) log;
5220 LogStream ls(log);
5221
5222 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5223
5224 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5225 const char* numa_mode = "membind";
5226
5227 if (Linux::is_running_in_interleave_mode()) {
5228 bmp = Linux::_numa_interleave_bitmask;
5229 numa_mode = "interleave";
5230 }
5231
5232 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5233 " Heap will be configured using NUMA memory nodes:", numa_mode);
5234
5235 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5236 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5237 ls.print(" %d", node);
5238 }
5239 }
5240 }
5241 }
5242
5243 // When NUMA requested, not-NUMA-aware allocations default to interleaving.
5244 if (UseNUMA && !UseNUMAInterleaving) {
5245 FLAG_SET_ERGO_IF_DEFAULT(UseNUMAInterleaving, true);
5246 }
5247
5248 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5249 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5250 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5251 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5252 // and disable adaptive resizing.
5253 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5254 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5255 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5256 UseAdaptiveSizePolicy = false;
5257 UseAdaptiveNUMAChunkSizing = false;
5258 }
5259 }
5260 }
5261
5262 // this is called _after_ the global arguments have been parsed
5263 jint os::init_2(void) {
5264
5265 // This could be set after os::Posix::init() but all platforms
5266 // have to set it the same so we have to mirror Solaris.
5267 DEBUG_ONLY(os::set_mutex_init_done();)
5268
5269 os::Posix::init_2();
5270
5271 Linux::fast_thread_clock_init();
5272
5273 // initialize suspend/resume support - must do this before signal_sets_init()
5274 if (SR_initialize() != 0) {
5275 perror("SR_initialize failed");
5276 return JNI_ERR;
5277 }
5278
5279 Linux::signal_sets_init();
5280 Linux::install_signal_handlers();
5281 // Initialize data for jdk.internal.misc.Signal
5282 if (!ReduceSignalUsage) {
5283 jdk_misc_signal_init();
5284 }
5285
5286 if (AdjustStackSizeForTLS) {
5287 get_minstack_init();
5288 }
5289
5290 // Check and sets minimum stack sizes against command line options
5291 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5292 return JNI_ERR;
5293 }
5294
5295 #if defined(IA32)
5296 // Need to ensure we've determined the process's initial stack to
5297 // perform the workaround
5298 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5299 workaround_expand_exec_shield_cs_limit();
5300 #else
5301 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5302 if (!suppress_primordial_thread_resolution) {
5303 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5304 }
5305 #endif
5306
5307 Linux::libpthread_init();
5308 Linux::sched_getcpu_init();
5309 log_info(os)("HotSpot is running with %s, %s",
5310 Linux::glibc_version(), Linux::libpthread_version());
5311
5312 if (UseNUMA || UseNUMAInterleaving) {
5313 Linux::numa_init();
5314 }
5315
5316 if (MaxFDLimit) {
5317 // set the number of file descriptors to max. print out error
5318 // if getrlimit/setrlimit fails but continue regardless.
5319 struct rlimit nbr_files;
5320 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5321 if (status != 0) {
5322 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5323 } else {
5324 nbr_files.rlim_cur = nbr_files.rlim_max;
5325 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5326 if (status != 0) {
5327 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5328 }
5329 }
5330 }
5331
5332 // at-exit methods are called in the reverse order of their registration.
5333 // atexit functions are called on return from main or as a result of a
5334 // call to exit(3C). There can be only 32 of these functions registered
5335 // and atexit() does not set errno.
5336
5337 if (PerfAllowAtExitRegistration) {
5338 // only register atexit functions if PerfAllowAtExitRegistration is set.
5339 // atexit functions can be delayed until process exit time, which
5340 // can be problematic for embedded VM situations. Embedded VMs should
5341 // call DestroyJavaVM() to assure that VM resources are released.
5342
5343 // note: perfMemory_exit_helper atexit function may be removed in
5344 // the future if the appropriate cleanup code can be added to the
5345 // VM_Exit VMOperation's doit method.
5346 if (atexit(perfMemory_exit_helper) != 0) {
5347 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5348 }
5349 }
5350
5351 // initialize thread priority policy
5352 prio_init();
5353
5354 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5355 set_coredump_filter(DAX_SHARED_BIT);
5356 }
5357
5358 if (DumpPrivateMappingsInCore) {
5359 set_coredump_filter(FILE_BACKED_PVT_BIT);
5360 }
5361
5362 if (DumpSharedMappingsInCore) {
5363 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5364 }
5365
5366 return JNI_OK;
5367 }
5368
5369 // older glibc versions don't have this macro (which expands to
5370 // an optimized bit-counting function) so we have to roll our own
5371 #ifndef CPU_COUNT
5372
5373 static int _cpu_count(const cpu_set_t* cpus) {
5374 int count = 0;
5375 // only look up to the number of configured processors
5376 for (int i = 0; i < os::processor_count(); i++) {
5377 if (CPU_ISSET(i, cpus)) {
5378 count++;
5379 }
5380 }
5381 return count;
5382 }
5383
5384 #define CPU_COUNT(cpus) _cpu_count(cpus)
5385
5386 #endif // CPU_COUNT
5387
5388 // Get the current number of available processors for this process.
5389 // This value can change at any time during a process's lifetime.
5390 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5391 // If it appears there may be more than 1024 processors then we do a
5392 // dynamic check - see 6515172 for details.
5393 // If anything goes wrong we fallback to returning the number of online
5394 // processors - which can be greater than the number available to the process.
5395 int os::Linux::active_processor_count() {
5396 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5397 cpu_set_t* cpus_p = &cpus;
5398 int cpus_size = sizeof(cpu_set_t);
5399
5400 int configured_cpus = os::processor_count(); // upper bound on available cpus
5401 int cpu_count = 0;
5402
5403 // old build platforms may not support dynamic cpu sets
5404 #ifdef CPU_ALLOC
5405
5406 // To enable easy testing of the dynamic path on different platforms we
5407 // introduce a diagnostic flag: UseCpuAllocPath
5408 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5409 // kernel may use a mask bigger than cpu_set_t
5410 log_trace(os)("active_processor_count: using dynamic path %s"
5411 "- configured processors: %d",
5412 UseCpuAllocPath ? "(forced) " : "",
5413 configured_cpus);
5414 cpus_p = CPU_ALLOC(configured_cpus);
5415 if (cpus_p != NULL) {
5416 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5417 // zero it just to be safe
5418 CPU_ZERO_S(cpus_size, cpus_p);
5419 }
5420 else {
5421 // failed to allocate so fallback to online cpus
5422 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5423 log_trace(os)("active_processor_count: "
5424 "CPU_ALLOC failed (%s) - using "
5425 "online processor count: %d",
5426 os::strerror(errno), online_cpus);
5427 return online_cpus;
5428 }
5429 }
5430 else {
5431 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5432 configured_cpus);
5433 }
5434 #else // CPU_ALLOC
5435 // these stubs won't be executed
5436 #define CPU_COUNT_S(size, cpus) -1
5437 #define CPU_FREE(cpus)
5438
5439 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5440 configured_cpus);
5441 #endif // CPU_ALLOC
5442
5443 // pid 0 means the current thread - which we have to assume represents the process
5444 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5445 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5446 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5447 }
5448 else {
5449 cpu_count = CPU_COUNT(cpus_p);
5450 }
5451 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5452 }
5453 else {
5454 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5455 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5456 "which may exceed available processors", os::strerror(errno), cpu_count);
5457 }
5458
5459 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5460 CPU_FREE(cpus_p);
5461 }
5462
5463 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5464 return cpu_count;
5465 }
5466
5467 // Determine the active processor count from one of
5468 // three different sources:
5469 //
5470 // 1. User option -XX:ActiveProcessorCount
5471 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5472 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5473 //
5474 // Option 1, if specified, will always override.
5475 // If the cgroup subsystem is active and configured, we
5476 // will return the min of the cgroup and option 2 results.
5477 // This is required since tools, such as numactl, that
5478 // alter cpu affinity do not update cgroup subsystem
5479 // cpuset configuration files.
5480 int os::active_processor_count() {
5481 // User has overridden the number of active processors
5482 if (ActiveProcessorCount > 0) {
5483 log_trace(os)("active_processor_count: "
5484 "active processor count set by user : %d",
5485 ActiveProcessorCount);
5486 return ActiveProcessorCount;
5487 }
5488
5489 int active_cpus;
5490 if (OSContainer::is_containerized()) {
5491 active_cpus = OSContainer::active_processor_count();
5492 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5493 active_cpus);
5494 } else {
5495 active_cpus = os::Linux::active_processor_count();
5496 }
5497
5498 return active_cpus;
5499 }
5500
5501 uint os::processor_id() {
5502 const int id = Linux::sched_getcpu();
5503 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5504 return (uint)id;
5505 }
5506
5507 void os::set_native_thread_name(const char *name) {
5508 if (Linux::_pthread_setname_np) {
5509 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5510 snprintf(buf, sizeof(buf), "%s", name);
5511 buf[sizeof(buf) - 1] = '\0';
5512 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5513 // ERANGE should not happen; all other errors should just be ignored.
5514 assert(rc != ERANGE, "pthread_setname_np failed");
5515 }
5516 }
5517
5518 bool os::bind_to_processor(uint processor_id) {
5519 // Not yet implemented.
5520 return false;
5521 }
5522
5523 ///
5524
5525 void os::SuspendedThreadTask::internal_do_task() {
5526 if (do_suspend(_thread->osthread())) {
5527 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5528 do_task(context);
5529 do_resume(_thread->osthread());
5530 }
5531 }
5532
5533 ////////////////////////////////////////////////////////////////////////////////
5534 // debug support
5535
5536 bool os::find(address addr, outputStream* st) {
5537 Dl_info dlinfo;
5538 memset(&dlinfo, 0, sizeof(dlinfo));
5539 if (dladdr(addr, &dlinfo) != 0) {
5540 st->print(PTR_FORMAT ": ", p2i(addr));
5541 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5542 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5543 p2i(addr) - p2i(dlinfo.dli_saddr));
5544 } else if (dlinfo.dli_fbase != NULL) {
5545 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5546 } else {
5547 st->print("<absolute address>");
5548 }
5549 if (dlinfo.dli_fname != NULL) {
5550 st->print(" in %s", dlinfo.dli_fname);
5551 }
5552 if (dlinfo.dli_fbase != NULL) {
5553 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5554 }
5555 st->cr();
5556
5557 if (Verbose) {
5558 // decode some bytes around the PC
5559 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5560 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5561 address lowest = (address) dlinfo.dli_sname;
5562 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5563 if (begin < lowest) begin = lowest;
5564 Dl_info dlinfo2;
5565 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5566 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5567 end = (address) dlinfo2.dli_saddr;
5568 }
5569 Disassembler::decode(begin, end, st);
5570 }
5571 return true;
5572 }
5573 return false;
5574 }
5575
5576 ////////////////////////////////////////////////////////////////////////////////
5577 // misc
5578
5579 // This does not do anything on Linux. This is basically a hook for being
5580 // able to use structured exception handling (thread-local exception filters)
5581 // on, e.g., Win32.
5582 void
5583 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5584 JavaCallArguments* args, Thread* thread) {
5585 f(value, method, args, thread);
5586 }
5587
5588 void os::print_statistics() {
5589 }
5590
5591 bool os::message_box(const char* title, const char* message) {
5592 int i;
5593 fdStream err(defaultStream::error_fd());
5594 for (i = 0; i < 78; i++) err.print_raw("=");
5595 err.cr();
5596 err.print_raw_cr(title);
5597 for (i = 0; i < 78; i++) err.print_raw("-");
5598 err.cr();
5599 err.print_raw_cr(message);
5600 for (i = 0; i < 78; i++) err.print_raw("=");
5601 err.cr();
5602
5603 char buf[16];
5604 // Prevent process from exiting upon "read error" without consuming all CPU
5605 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5606
5607 return buf[0] == 'y' || buf[0] == 'Y';
5608 }
5609
5610 // Is a (classpath) directory empty?
5611 bool os::dir_is_empty(const char* path) {
5612 DIR *dir = NULL;
5613 struct dirent *ptr;
5614
5615 dir = opendir(path);
5616 if (dir == NULL) return true;
5617
5618 // Scan the directory
5619 bool result = true;
5620 while (result && (ptr = readdir(dir)) != NULL) {
5621 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5622 result = false;
5623 }
5624 }
5625 closedir(dir);
5626 return result;
5627 }
5628
5629 // This code originates from JDK's sysOpen and open64_w
5630 // from src/solaris/hpi/src/system_md.c
5631
5632 int os::open(const char *path, int oflag, int mode) {
5633 if (strlen(path) > MAX_PATH - 1) {
5634 errno = ENAMETOOLONG;
5635 return -1;
5636 }
5637
5638 // All file descriptors that are opened in the Java process and not
5639 // specifically destined for a subprocess should have the close-on-exec
5640 // flag set. If we don't set it, then careless 3rd party native code
5641 // might fork and exec without closing all appropriate file descriptors
5642 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5643 // turn might:
5644 //
5645 // - cause end-of-file to fail to be detected on some file
5646 // descriptors, resulting in mysterious hangs, or
5647 //
5648 // - might cause an fopen in the subprocess to fail on a system
5649 // suffering from bug 1085341.
5650 //
5651 // (Yes, the default setting of the close-on-exec flag is a Unix
5652 // design flaw)
5653 //
5654 // See:
5655 // 1085341: 32-bit stdio routines should support file descriptors >255
5656 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5657 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5658 //
5659 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5660 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5661 // because it saves a system call and removes a small window where the flag
5662 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5663 // and we fall back to using FD_CLOEXEC (see below).
5664 #ifdef O_CLOEXEC
5665 oflag |= O_CLOEXEC;
5666 #endif
5667
5668 int fd = ::open64(path, oflag, mode);
5669 if (fd == -1) return -1;
5670
5671 //If the open succeeded, the file might still be a directory
5672 {
5673 struct stat64 buf64;
5674 int ret = ::fstat64(fd, &buf64);
5675 int st_mode = buf64.st_mode;
5676
5677 if (ret != -1) {
5678 if ((st_mode & S_IFMT) == S_IFDIR) {
5679 errno = EISDIR;
5680 ::close(fd);
5681 return -1;
5682 }
5683 } else {
5684 ::close(fd);
5685 return -1;
5686 }
5687 }
5688
5689 #ifdef FD_CLOEXEC
5690 // Validate that the use of the O_CLOEXEC flag on open above worked.
5691 // With recent kernels, we will perform this check exactly once.
5692 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5693 if (!O_CLOEXEC_is_known_to_work) {
5694 int flags = ::fcntl(fd, F_GETFD);
5695 if (flags != -1) {
5696 if ((flags & FD_CLOEXEC) != 0)
5697 O_CLOEXEC_is_known_to_work = 1;
5698 else
5699 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5700 }
5701 }
5702 #endif
5703
5704 return fd;
5705 }
5706
5707
5708 // create binary file, rewriting existing file if required
5709 int os::create_binary_file(const char* path, bool rewrite_existing) {
5710 int oflags = O_WRONLY | O_CREAT;
5711 if (!rewrite_existing) {
5712 oflags |= O_EXCL;
5713 }
5714 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5715 }
5716
5717 // return current position of file pointer
5718 jlong os::current_file_offset(int fd) {
5719 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5720 }
5721
5722 // move file pointer to the specified offset
5723 jlong os::seek_to_file_offset(int fd, jlong offset) {
5724 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5725 }
5726
5727 // This code originates from JDK's sysAvailable
5728 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5729
5730 int os::available(int fd, jlong *bytes) {
5731 jlong cur, end;
5732 int mode;
5733 struct stat64 buf64;
5734
5735 if (::fstat64(fd, &buf64) >= 0) {
5736 mode = buf64.st_mode;
5737 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5738 int n;
5739 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5740 *bytes = n;
5741 return 1;
5742 }
5743 }
5744 }
5745 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5746 return 0;
5747 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5748 return 0;
5749 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5750 return 0;
5751 }
5752 *bytes = end - cur;
5753 return 1;
5754 }
5755
5756 // Map a block of memory.
5757 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5758 char *addr, size_t bytes, bool read_only,
5759 bool allow_exec) {
5760 int prot;
5761 int flags = MAP_PRIVATE;
5762
5763 if (read_only) {
5764 prot = PROT_READ;
5765 } else {
5766 prot = PROT_READ | PROT_WRITE;
5767 }
5768
5769 if (allow_exec) {
5770 prot |= PROT_EXEC;
5771 }
5772
5773 if (addr != NULL) {
5774 flags |= MAP_FIXED;
5775 }
5776
5777 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5778 fd, file_offset);
5779 if (mapped_address == MAP_FAILED) {
5780 return NULL;
5781 }
5782 return mapped_address;
5783 }
5784
5785
5786 // Remap a block of memory.
5787 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5788 char *addr, size_t bytes, bool read_only,
5789 bool allow_exec) {
5790 // same as map_memory() on this OS
5791 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5792 allow_exec);
5793 }
5794
5795
5796 // Unmap a block of memory.
5797 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5798 return munmap(addr, bytes) == 0;
5799 }
5800
5801 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5802
5803 static jlong fast_cpu_time(Thread *thread) {
5804 clockid_t clockid;
5805 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5806 &clockid);
5807 if (rc == 0) {
5808 return os::Linux::fast_thread_cpu_time(clockid);
5809 } else {
5810 // It's possible to encounter a terminated native thread that failed
5811 // to detach itself from the VM - which should result in ESRCH.
5812 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5813 return -1;
5814 }
5815 }
5816
5817 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5818 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5819 // of a thread.
5820 //
5821 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5822 // the fast estimate available on the platform.
5823
5824 jlong os::current_thread_cpu_time() {
5825 if (os::Linux::supports_fast_thread_cpu_time()) {
5826 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5827 } else {
5828 // return user + sys since the cost is the same
5829 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5830 }
5831 }
5832
5833 jlong os::thread_cpu_time(Thread* thread) {
5834 // consistent with what current_thread_cpu_time() returns
5835 if (os::Linux::supports_fast_thread_cpu_time()) {
5836 return fast_cpu_time(thread);
5837 } else {
5838 return slow_thread_cpu_time(thread, true /* user + sys */);
5839 }
5840 }
5841
5842 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5843 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5844 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5845 } else {
5846 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5847 }
5848 }
5849
5850 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5851 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5852 return fast_cpu_time(thread);
5853 } else {
5854 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5855 }
5856 }
5857
5858 // -1 on error.
5859 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5860 pid_t tid = thread->osthread()->thread_id();
5861 char *s;
5862 char stat[2048];
5863 int statlen;
5864 char proc_name[64];
5865 int count;
5866 long sys_time, user_time;
5867 char cdummy;
5868 int idummy;
5869 long ldummy;
5870 FILE *fp;
5871
5872 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5873 fp = fopen(proc_name, "r");
5874 if (fp == NULL) return -1;
5875 statlen = fread(stat, 1, 2047, fp);
5876 stat[statlen] = '\0';
5877 fclose(fp);
5878
5879 // Skip pid and the command string. Note that we could be dealing with
5880 // weird command names, e.g. user could decide to rename java launcher
5881 // to "java 1.4.2 :)", then the stat file would look like
5882 // 1234 (java 1.4.2 :)) R ... ...
5883 // We don't really need to know the command string, just find the last
5884 // occurrence of ")" and then start parsing from there. See bug 4726580.
5885 s = strrchr(stat, ')');
5886 if (s == NULL) return -1;
5887
5888 // Skip blank chars
5889 do { s++; } while (s && isspace(*s));
5890
5891 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5892 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5893 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5894 &user_time, &sys_time);
5895 if (count != 13) return -1;
5896 if (user_sys_cpu_time) {
5897 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5898 } else {
5899 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5900 }
5901 }
5902
5903 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5904 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5905 info_ptr->may_skip_backward = false; // elapsed time not wall time
5906 info_ptr->may_skip_forward = false; // elapsed time not wall time
5907 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5908 }
5909
5910 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5911 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5912 info_ptr->may_skip_backward = false; // elapsed time not wall time
5913 info_ptr->may_skip_forward = false; // elapsed time not wall time
5914 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5915 }
5916
5917 bool os::is_thread_cpu_time_supported() {
5918 return true;
5919 }
5920
5921 // System loadavg support. Returns -1 if load average cannot be obtained.
5922 // Linux doesn't yet have a (official) notion of processor sets,
5923 // so just return the system wide load average.
5924 int os::loadavg(double loadavg[], int nelem) {
5925 return ::getloadavg(loadavg, nelem);
5926 }
5927
5928 void os::pause() {
5929 char filename[MAX_PATH];
5930 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5931 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5932 } else {
5933 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5934 }
5935
5936 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5937 if (fd != -1) {
5938 struct stat buf;
5939 ::close(fd);
5940 while (::stat(filename, &buf) == 0) {
5941 (void)::poll(NULL, 0, 100);
5942 }
5943 } else {
5944 jio_fprintf(stderr,
5945 "Could not open pause file '%s', continuing immediately.\n", filename);
5946 }
5947 }
5948
5949 extern char** environ;
5950
5951 // Run the specified command in a separate process. Return its exit value,
5952 // or -1 on failure (e.g. can't fork a new process).
5953 // Unlike system(), this function can be called from signal handler. It
5954 // doesn't block SIGINT et al.
5955 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5956 const char * argv[4] = {"sh", "-c", cmd, NULL};
5957
5958 pid_t pid ;
5959
5960 if (use_vfork_if_available) {
5961 pid = vfork();
5962 } else {
5963 pid = fork();
5964 }
5965
5966 if (pid < 0) {
5967 // fork failed
5968 return -1;
5969
5970 } else if (pid == 0) {
5971 // child process
5972
5973 execve("/bin/sh", (char* const*)argv, environ);
5974
5975 // execve failed
5976 _exit(-1);
5977
5978 } else {
5979 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5980 // care about the actual exit code, for now.
5981
5982 int status;
5983
5984 // Wait for the child process to exit. This returns immediately if
5985 // the child has already exited. */
5986 while (waitpid(pid, &status, 0) < 0) {
5987 switch (errno) {
5988 case ECHILD: return 0;
5989 case EINTR: break;
5990 default: return -1;
5991 }
5992 }
5993
5994 if (WIFEXITED(status)) {
5995 // The child exited normally; get its exit code.
5996 return WEXITSTATUS(status);
5997 } else if (WIFSIGNALED(status)) {
5998 // The child exited because of a signal
5999 // The best value to return is 0x80 + signal number,
6000 // because that is what all Unix shells do, and because
6001 // it allows callers to distinguish between process exit and
6002 // process death by signal.
6003 return 0x80 + WTERMSIG(status);
6004 } else {
6005 // Unknown exit code; pass it through
6006 return status;
6007 }
6008 }
6009 }
6010
6011 // Get the default path to the core file
6012 // Returns the length of the string
6013 int os::get_core_path(char* buffer, size_t bufferSize) {
6014 /*
6015 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
6016 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
6017 */
6018 const int core_pattern_len = 129;
6019 char core_pattern[core_pattern_len] = {0};
6020
6021 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
6022 if (core_pattern_file == -1) {
6023 return -1;
6024 }
6025
6026 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
6027 ::close(core_pattern_file);
6028 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
6029 return -1;
6030 }
6031 if (core_pattern[ret-1] == '\n') {
6032 core_pattern[ret-1] = '\0';
6033 } else {
6034 core_pattern[ret] = '\0';
6035 }
6036
6037 // Replace the %p in the core pattern with the process id. NOTE: we do this
6038 // only if the pattern doesn't start with "|", and we support only one %p in
6039 // the pattern.
6040 char *pid_pos = strstr(core_pattern, "%p");
6041 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
6042 int written;
6043
6044 if (core_pattern[0] == '/') {
6045 if (pid_pos != NULL) {
6046 *pid_pos = '\0';
6047 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
6048 current_process_id(), tail);
6049 } else {
6050 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6051 }
6052 } else {
6053 char cwd[PATH_MAX];
6054
6055 const char* p = get_current_directory(cwd, PATH_MAX);
6056 if (p == NULL) {
6057 return -1;
6058 }
6059
6060 if (core_pattern[0] == '|') {
6061 written = jio_snprintf(buffer, bufferSize,
6062 "\"%s\" (or dumping to %s/core.%d)",
6063 &core_pattern[1], p, current_process_id());
6064 } else if (pid_pos != NULL) {
6065 *pid_pos = '\0';
6066 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
6067 current_process_id(), tail);
6068 } else {
6069 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6070 }
6071 }
6072
6073 if (written < 0) {
6074 return -1;
6075 }
6076
6077 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6078 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6079
6080 if (core_uses_pid_file != -1) {
6081 char core_uses_pid = 0;
6082 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6083 ::close(core_uses_pid_file);
6084
6085 if (core_uses_pid == '1') {
6086 jio_snprintf(buffer + written, bufferSize - written,
6087 ".%d", current_process_id());
6088 }
6089 }
6090 }
6091
6092 return strlen(buffer);
6093 }
6094
6095 bool os::start_debugging(char *buf, int buflen) {
6096 int len = (int)strlen(buf);
6097 char *p = &buf[len];
6098
6099 jio_snprintf(p, buflen-len,
6100 "\n\n"
6101 "Do you want to debug the problem?\n\n"
6102 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6103 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6104 "Otherwise, press RETURN to abort...",
6105 os::current_process_id(), os::current_process_id(),
6106 os::current_thread_id(), os::current_thread_id());
6107
6108 bool yes = os::message_box("Unexpected Error", buf);
6109
6110 if (yes) {
6111 // yes, user asked VM to launch debugger
6112 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6113 os::current_process_id(), os::current_process_id());
6114
6115 os::fork_and_exec(buf);
6116 yes = false;
6117 }
6118 return yes;
6119 }
6120
6121
6122 // Java/Compiler thread:
6123 //
6124 // Low memory addresses
6125 // P0 +------------------------+
6126 // | |\ Java thread created by VM does not have glibc
6127 // | glibc guard page | - guard page, attached Java thread usually has
6128 // | |/ 1 glibc guard page.
6129 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6130 // | |\
6131 // | HotSpot Guard Pages | - red, yellow and reserved pages
6132 // | |/
6133 // +------------------------+ JavaThread::stack_reserved_zone_base()
6134 // | |\
6135 // | Normal Stack | -
6136 // | |/
6137 // P2 +------------------------+ Thread::stack_base()
6138 //
6139 // Non-Java thread:
6140 //
6141 // Low memory addresses
6142 // P0 +------------------------+
6143 // | |\
6144 // | glibc guard page | - usually 1 page
6145 // | |/
6146 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6147 // | |\
6148 // | Normal Stack | -
6149 // | |/
6150 // P2 +------------------------+ Thread::stack_base()
6151 //
6152 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6153 // returned from pthread_attr_getstack().
6154 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6155 // of the stack size given in pthread_attr. We work around this for
6156 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6157 //
6158 #ifndef ZERO
6159 static void current_stack_region(address * bottom, size_t * size) {
6160 if (os::is_primordial_thread()) {
6161 // primordial thread needs special handling because pthread_getattr_np()
6162 // may return bogus value.
6163 *bottom = os::Linux::initial_thread_stack_bottom();
6164 *size = os::Linux::initial_thread_stack_size();
6165 } else {
6166 pthread_attr_t attr;
6167
6168 int rslt = pthread_getattr_np(pthread_self(), &attr);
6169
6170 // JVM needs to know exact stack location, abort if it fails
6171 if (rslt != 0) {
6172 if (rslt == ENOMEM) {
6173 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6174 } else {
6175 fatal("pthread_getattr_np failed with error = %d", rslt);
6176 }
6177 }
6178
6179 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6180 fatal("Cannot locate current stack attributes!");
6181 }
6182
6183 // Work around NPTL stack guard error.
6184 size_t guard_size = 0;
6185 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6186 if (rslt != 0) {
6187 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6188 }
6189 *bottom += guard_size;
6190 *size -= guard_size;
6191
6192 pthread_attr_destroy(&attr);
6193
6194 }
6195 assert(os::current_stack_pointer() >= *bottom &&
6196 os::current_stack_pointer() < *bottom + *size, "just checking");
6197 }
6198
6199 address os::current_stack_base() {
6200 address bottom;
6201 size_t size;
6202 current_stack_region(&bottom, &size);
6203 return (bottom + size);
6204 }
6205
6206 size_t os::current_stack_size() {
6207 // This stack size includes the usable stack and HotSpot guard pages
6208 // (for the threads that have Hotspot guard pages).
6209 address bottom;
6210 size_t size;
6211 current_stack_region(&bottom, &size);
6212 return size;
6213 }
6214 #endif
6215
6216 static inline struct timespec get_mtime(const char* filename) {
6217 struct stat st;
6218 int ret = os::stat(filename, &st);
6219 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6220 return st.st_mtim;
6221 }
6222
6223 int os::compare_file_modified_times(const char* file1, const char* file2) {
6224 struct timespec filetime1 = get_mtime(file1);
6225 struct timespec filetime2 = get_mtime(file2);
6226 int diff = filetime1.tv_sec - filetime2.tv_sec;
6227 if (diff == 0) {
6228 return filetime1.tv_nsec - filetime2.tv_nsec;
6229 }
6230 return diff;
6231 }
6232
6233 bool os::supports_map_sync() {
6234 return true;
6235 }
6236
6237 /////////////// Unit tests ///////////////
6238
6239 #ifndef PRODUCT
6240
6241 class TestReserveMemorySpecial : AllStatic {
6242 public:
6243 static void small_page_write(void* addr, size_t size) {
6244 size_t page_size = os::vm_page_size();
6245
6246 char* end = (char*)addr + size;
6247 for (char* p = (char*)addr; p < end; p += page_size) {
6248 *p = 1;
6249 }
6250 }
6251
6252 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6253 if (!UseHugeTLBFS) {
6254 return;
6255 }
6256
6257 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6258
6259 if (addr != NULL) {
6260 small_page_write(addr, size);
6261
6262 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6263 }
6264 }
6265
6266 static void test_reserve_memory_special_huge_tlbfs_only() {
6267 if (!UseHugeTLBFS) {
6268 return;
6269 }
6270
6271 size_t lp = os::large_page_size();
6272
6273 for (size_t size = lp; size <= lp * 10; size += lp) {
6274 test_reserve_memory_special_huge_tlbfs_only(size);
6275 }
6276 }
6277
6278 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6279 size_t lp = os::large_page_size();
6280 size_t ag = os::vm_allocation_granularity();
6281
6282 // sizes to test
6283 const size_t sizes[] = {
6284 lp, lp + ag, lp + lp / 2, lp * 2,
6285 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6286 lp * 10, lp * 10 + lp / 2
6287 };
6288 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6289
6290 // For each size/alignment combination, we test three scenarios:
6291 // 1) with req_addr == NULL
6292 // 2) with a non-null req_addr at which we expect to successfully allocate
6293 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6294 // expect the allocation to either fail or to ignore req_addr
6295
6296 // Pre-allocate two areas; they shall be as large as the largest allocation
6297 // and aligned to the largest alignment we will be testing.
6298 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6299 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6300 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6301 -1, 0);
6302 assert(mapping1 != MAP_FAILED, "should work");
6303
6304 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6305 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6306 -1, 0);
6307 assert(mapping2 != MAP_FAILED, "should work");
6308
6309 // Unmap the first mapping, but leave the second mapping intact: the first
6310 // mapping will serve as a value for a "good" req_addr (case 2). The second
6311 // mapping, still intact, as "bad" req_addr (case 3).
6312 ::munmap(mapping1, mapping_size);
6313
6314 // Case 1
6315 for (int i = 0; i < num_sizes; i++) {
6316 const size_t size = sizes[i];
6317 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6318 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6319 if (p != NULL) {
6320 assert(is_aligned(p, alignment), "must be");
6321 small_page_write(p, size);
6322 os::Linux::release_memory_special_huge_tlbfs(p, size);
6323 }
6324 }
6325 }
6326
6327 // Case 2
6328 for (int i = 0; i < num_sizes; i++) {
6329 const size_t size = sizes[i];
6330 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6331 char* const req_addr = align_up(mapping1, alignment);
6332 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6333 if (p != NULL) {
6334 assert(p == req_addr, "must be");
6335 small_page_write(p, size);
6336 os::Linux::release_memory_special_huge_tlbfs(p, size);
6337 }
6338 }
6339 }
6340
6341 // Case 3
6342 for (int i = 0; i < num_sizes; i++) {
6343 const size_t size = sizes[i];
6344 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6345 char* const req_addr = align_up(mapping2, alignment);
6346 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6347 // as the area around req_addr contains already existing mappings, the API should always
6348 // return NULL (as per contract, it cannot return another address)
6349 assert(p == NULL, "must be");
6350 }
6351 }
6352
6353 ::munmap(mapping2, mapping_size);
6354
6355 }
6356
6357 static void test_reserve_memory_special_huge_tlbfs() {
6358 if (!UseHugeTLBFS) {
6359 return;
6360 }
6361
6362 test_reserve_memory_special_huge_tlbfs_only();
6363 test_reserve_memory_special_huge_tlbfs_mixed();
6364 }
6365
6366 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6367 if (!UseSHM) {
6368 return;
6369 }
6370
6371 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6372
6373 if (addr != NULL) {
6374 assert(is_aligned(addr, alignment), "Check");
6375 assert(is_aligned(addr, os::large_page_size()), "Check");
6376
6377 small_page_write(addr, size);
6378
6379 os::Linux::release_memory_special_shm(addr, size);
6380 }
6381 }
6382
6383 static void test_reserve_memory_special_shm() {
6384 size_t lp = os::large_page_size();
6385 size_t ag = os::vm_allocation_granularity();
6386
6387 for (size_t size = ag; size < lp * 3; size += ag) {
6388 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6389 test_reserve_memory_special_shm(size, alignment);
6390 }
6391 }
6392 }
6393
6394 static void test() {
6395 test_reserve_memory_special_huge_tlbfs();
6396 test_reserve_memory_special_shm();
6397 }
6398 };
6399
6400 void TestReserveMemorySpecial_test() {
6401 TestReserveMemorySpecial::test();
6402 }
6403
6404 #endif