1 /*
2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/disassembler.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "logging/log.hpp"
36 #include "logging/logStream.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/filemap.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_linux.inline.hpp"
41 #include "os_posix.inline.hpp"
42 #include "os_share_linux.hpp"
43 #include "osContainer_linux.hpp"
44 #include "prims/jniFastGetField.hpp"
45 #include "prims/jvm_misc.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/atomic.hpp"
48 #include "runtime/extendedPC.hpp"
49 #include "runtime/globals.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "runtime/init.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/objectMonitor.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/perfMemory.hpp"
58 #include "runtime/sharedRuntime.hpp"
59 #include "runtime/statSampler.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/thread.inline.hpp"
62 #include "runtime/threadCritical.hpp"
63 #include "runtime/threadSMR.hpp"
64 #include "runtime/timer.hpp"
65 #include "runtime/vm_version.hpp"
66 #include "semaphore_posix.hpp"
67 #include "services/attachListener.hpp"
68 #include "services/memTracker.hpp"
69 #include "services/runtimeService.hpp"
70 #include "utilities/align.hpp"
71 #include "utilities/decoder.hpp"
72 #include "utilities/defaultStream.hpp"
73 #include "utilities/events.hpp"
74 #include "utilities/elfFile.hpp"
75 #include "utilities/growableArray.hpp"
76 #include "utilities/macros.hpp"
77 #include "utilities/powerOfTwo.hpp"
78 #include "utilities/vmError.hpp"
79
80 // put OS-includes here
81 # include <sys/types.h>
82 # include <sys/mman.h>
83 # include <sys/stat.h>
84 # include <sys/select.h>
85 # include <pthread.h>
86 # include <signal.h>
87 # include <endian.h>
88 # include <errno.h>
89 # include <dlfcn.h>
90 # include <stdio.h>
91 # include <unistd.h>
92 # include <sys/resource.h>
93 # include <pthread.h>
94 # include <sys/stat.h>
95 # include <sys/time.h>
96 # include <sys/times.h>
97 # include <sys/utsname.h>
98 # include <sys/socket.h>
99 # include <sys/wait.h>
100 # include <pwd.h>
101 # include <poll.h>
102 # include <fcntl.h>
103 # include <string.h>
104 # include <syscall.h>
105 # include <sys/sysinfo.h>
106 # include <gnu/libc-version.h>
107 # include <sys/ipc.h>
108 # include <sys/shm.h>
109 # include <link.h>
110 # include <stdint.h>
111 # include <inttypes.h>
112 # include <sys/ioctl.h>
113 # include <linux/elf-em.h>
114
115 #ifndef _GNU_SOURCE
116 #define _GNU_SOURCE
117 #include <sched.h>
118 #undef _GNU_SOURCE
119 #else
120 #include <sched.h>
121 #endif
122
123 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
124 // getrusage() is prepared to handle the associated failure.
125 #ifndef RUSAGE_THREAD
126 #define RUSAGE_THREAD (1) /* only the calling thread */
127 #endif
128
129 #define MAX_PATH (2 * K)
130
131 #define MAX_SECS 100000000
132
133 // for timer info max values which include all bits
134 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
135
136 enum CoredumpFilterBit {
137 FILE_BACKED_PVT_BIT = 1 << 2,
138 FILE_BACKED_SHARED_BIT = 1 << 3,
139 LARGEPAGES_BIT = 1 << 6,
140 DAX_SHARED_BIT = 1 << 8
141 };
142
143 ////////////////////////////////////////////////////////////////////////////////
144 // global variables
145 julong os::Linux::_physical_memory = 0;
146
147 address os::Linux::_initial_thread_stack_bottom = NULL;
148 uintptr_t os::Linux::_initial_thread_stack_size = 0;
149
150 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
151 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
152 pthread_t os::Linux::_main_thread;
153 int os::Linux::_page_size = -1;
154 bool os::Linux::_supports_fast_thread_cpu_time = false;
155 const char * os::Linux::_glibc_version = NULL;
156 const char * os::Linux::_libpthread_version = NULL;
157
158 static jlong initial_time_count=0;
159
160 static int clock_tics_per_sec = 100;
161
162 // If the VM might have been created on the primordial thread, we need to resolve the
163 // primordial thread stack bounds and check if the current thread might be the
164 // primordial thread in places. If we know that the primordial thread is never used,
165 // such as when the VM was created by one of the standard java launchers, we can
166 // avoid this
167 static bool suppress_primordial_thread_resolution = false;
168
169 // For diagnostics to print a message once. see run_periodic_checks
170 static sigset_t check_signal_done;
171 static bool check_signals = true;
172
173 // Signal number used to suspend/resume a thread
174
175 // do not use any signal number less than SIGSEGV, see 4355769
176 static int SR_signum = SIGUSR2;
177 sigset_t SR_sigset;
178
179 // utility functions
180
181 static int SR_initialize();
182
183 julong os::available_memory() {
184 return Linux::available_memory();
185 }
186
187 julong os::Linux::available_memory() {
188 // values in struct sysinfo are "unsigned long"
189 struct sysinfo si;
190 julong avail_mem;
191
192 if (OSContainer::is_containerized()) {
193 jlong mem_limit, mem_usage;
194 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
195 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
196 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
197 }
198 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
199 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
200 }
201 if (mem_limit > 0 && mem_usage > 0 ) {
202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
203 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
204 return avail_mem;
205 }
206 }
207
208 sysinfo(&si);
209 avail_mem = (julong)si.freeram * si.mem_unit;
210 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
211 return avail_mem;
212 }
213
214 julong os::physical_memory() {
215 jlong phys_mem = 0;
216 if (OSContainer::is_containerized()) {
217 jlong mem_limit;
218 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
219 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
220 return mem_limit;
221 }
222 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
223 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
224 }
225
226 phys_mem = Linux::physical_memory();
227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
228 return phys_mem;
229 }
230
231 static uint64_t initial_total_ticks = 0;
232 static uint64_t initial_steal_ticks = 0;
233 static bool has_initial_tick_info = false;
234
235 static void next_line(FILE *f) {
236 int c;
237 do {
238 c = fgetc(f);
239 } while (c != '\n' && c != EOF);
240 }
241
242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
243 FILE* fh;
244 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
246 // irq: time servicing interrupts; softirq: time servicing softirqs
247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
249 uint64_t stealTicks = 0;
250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
251 // control of the Linux kernel
252 uint64_t guestNiceTicks = 0;
253 int logical_cpu = -1;
254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
255 int n;
256
257 memset(pticks, 0, sizeof(CPUPerfTicks));
258
259 if ((fh = fopen("/proc/stat", "r")) == NULL) {
260 return false;
261 }
262
263 if (which_logical_cpu == -1) {
264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
266 UINT64_FORMAT " " UINT64_FORMAT " ",
267 &userTicks, &niceTicks, &systemTicks, &idleTicks,
268 &iowTicks, &irqTicks, &sirqTicks,
269 &stealTicks, &guestNiceTicks);
270 } else {
271 // Move to next line
272 next_line(fh);
273
274 // find the line for requested cpu faster to just iterate linefeeds?
275 for (int i = 0; i < which_logical_cpu; i++) {
276 next_line(fh);
277 }
278
279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
281 UINT64_FORMAT " " UINT64_FORMAT " ",
282 &logical_cpu, &userTicks, &niceTicks,
283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
284 &stealTicks, &guestNiceTicks);
285 }
286
287 fclose(fh);
288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
289 return false;
290 }
291 pticks->used = userTicks + niceTicks;
292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
295
296 if (n > required_tickinfo_count + 3) {
297 pticks->steal = stealTicks;
298 pticks->has_steal_ticks = true;
299 } else {
300 pticks->steal = 0;
301 pticks->has_steal_ticks = false;
302 }
303
304 return true;
305 }
306
307 // Return true if user is running as root.
308
309 bool os::have_special_privileges() {
310 static bool init = false;
311 static bool privileges = false;
312 if (!init) {
313 privileges = (getuid() != geteuid()) || (getgid() != getegid());
314 init = true;
315 }
316 return privileges;
317 }
318
319
320 #ifndef SYS_gettid
321 // i386: 224, ia64: 1105, amd64: 186, sparc 143
322 #ifdef __ia64__
323 #define SYS_gettid 1105
324 #else
325 #ifdef __i386__
326 #define SYS_gettid 224
327 #else
328 #ifdef __amd64__
329 #define SYS_gettid 186
330 #else
331 #ifdef __sparc__
332 #define SYS_gettid 143
333 #else
334 #error define gettid for the arch
335 #endif
336 #endif
337 #endif
338 #endif
339 #endif
340
341
342 // pid_t gettid()
343 //
344 // Returns the kernel thread id of the currently running thread. Kernel
345 // thread id is used to access /proc.
346 pid_t os::Linux::gettid() {
347 int rslt = syscall(SYS_gettid);
348 assert(rslt != -1, "must be."); // old linuxthreads implementation?
349 return (pid_t)rslt;
350 }
351
352 // Most versions of linux have a bug where the number of processors are
353 // determined by looking at the /proc file system. In a chroot environment,
354 // the system call returns 1.
355 static bool unsafe_chroot_detected = false;
356 static const char *unstable_chroot_error = "/proc file system not found.\n"
357 "Java may be unstable running multithreaded in a chroot "
358 "environment on Linux when /proc filesystem is not mounted.";
359
360 void os::Linux::initialize_system_info() {
361 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
362 if (processor_count() == 1) {
363 pid_t pid = os::Linux::gettid();
364 char fname[32];
365 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
366 FILE *fp = fopen(fname, "r");
367 if (fp == NULL) {
368 unsafe_chroot_detected = true;
369 } else {
370 fclose(fp);
371 }
372 }
373 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
374 assert(processor_count() > 0, "linux error");
375 }
376
377 void os::init_system_properties_values() {
378 // The next steps are taken in the product version:
379 //
380 // Obtain the JAVA_HOME value from the location of libjvm.so.
381 // This library should be located at:
382 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
383 //
384 // If "/jre/lib/" appears at the right place in the path, then we
385 // assume libjvm.so is installed in a JDK and we use this path.
386 //
387 // Otherwise exit with message: "Could not create the Java virtual machine."
388 //
389 // The following extra steps are taken in the debugging version:
390 //
391 // If "/jre/lib/" does NOT appear at the right place in the path
392 // instead of exit check for $JAVA_HOME environment variable.
393 //
394 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
395 // then we append a fake suffix "hotspot/libjvm.so" to this path so
396 // it looks like libjvm.so is installed there
397 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
398 //
399 // Otherwise exit.
400 //
401 // Important note: if the location of libjvm.so changes this
402 // code needs to be changed accordingly.
403
404 // See ld(1):
405 // The linker uses the following search paths to locate required
406 // shared libraries:
407 // 1: ...
408 // ...
409 // 7: The default directories, normally /lib and /usr/lib.
410 #ifndef OVERRIDE_LIBPATH
411 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
412 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
413 #else
414 #define DEFAULT_LIBPATH "/lib:/usr/lib"
415 #endif
416 #else
417 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
418 #endif
419
420 // Base path of extensions installed on the system.
421 #define SYS_EXT_DIR "/usr/java/packages"
422 #define EXTENSIONS_DIR "/lib/ext"
423
424 // Buffer that fits several sprintfs.
425 // Note that the space for the colon and the trailing null are provided
426 // by the nulls included by the sizeof operator.
427 const size_t bufsize =
428 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
429 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
430 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
431
432 // sysclasspath, java_home, dll_dir
433 {
434 char *pslash;
435 os::jvm_path(buf, bufsize);
436
437 // Found the full path to libjvm.so.
438 // Now cut the path to <java_home>/jre if we can.
439 pslash = strrchr(buf, '/');
440 if (pslash != NULL) {
441 *pslash = '\0'; // Get rid of /libjvm.so.
442 }
443 pslash = strrchr(buf, '/');
444 if (pslash != NULL) {
445 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
446 }
447 Arguments::set_dll_dir(buf);
448
449 if (pslash != NULL) {
450 pslash = strrchr(buf, '/');
451 if (pslash != NULL) {
452 *pslash = '\0'; // Get rid of /lib.
453 }
454 }
455 Arguments::set_java_home(buf);
456 if (!set_boot_path('/', ':')) {
457 vm_exit_during_initialization("Failed setting boot class path.", NULL);
458 }
459 }
460
461 // Where to look for native libraries.
462 //
463 // Note: Due to a legacy implementation, most of the library path
464 // is set in the launcher. This was to accomodate linking restrictions
465 // on legacy Linux implementations (which are no longer supported).
466 // Eventually, all the library path setting will be done here.
467 //
468 // However, to prevent the proliferation of improperly built native
469 // libraries, the new path component /usr/java/packages is added here.
470 // Eventually, all the library path setting will be done here.
471 {
472 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
473 // should always exist (until the legacy problem cited above is
474 // addressed).
475 const char *v = ::getenv("LD_LIBRARY_PATH");
476 const char *v_colon = ":";
477 if (v == NULL) { v = ""; v_colon = ""; }
478 // That's +1 for the colon and +1 for the trailing '\0'.
479 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
480 strlen(v) + 1 +
481 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
482 mtInternal);
483 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
484 Arguments::set_library_path(ld_library_path);
485 FREE_C_HEAP_ARRAY(char, ld_library_path);
486 }
487
488 // Extensions directories.
489 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
490 Arguments::set_ext_dirs(buf);
491
492 FREE_C_HEAP_ARRAY(char, buf);
493
494 #undef DEFAULT_LIBPATH
495 #undef SYS_EXT_DIR
496 #undef EXTENSIONS_DIR
497 }
498
499 ////////////////////////////////////////////////////////////////////////////////
500 // breakpoint support
501
502 void os::breakpoint() {
503 BREAKPOINT;
504 }
505
506 extern "C" void breakpoint() {
507 // use debugger to set breakpoint here
508 }
509
510 ////////////////////////////////////////////////////////////////////////////////
511 // signal support
512
513 debug_only(static bool signal_sets_initialized = false);
514 static sigset_t unblocked_sigs, vm_sigs;
515
516 void os::Linux::signal_sets_init() {
517 // Should also have an assertion stating we are still single-threaded.
518 assert(!signal_sets_initialized, "Already initialized");
519 // Fill in signals that are necessarily unblocked for all threads in
520 // the VM. Currently, we unblock the following signals:
521 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
522 // by -Xrs (=ReduceSignalUsage));
523 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
524 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
525 // the dispositions or masks wrt these signals.
526 // Programs embedding the VM that want to use the above signals for their
527 // own purposes must, at this time, use the "-Xrs" option to prevent
528 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
529 // (See bug 4345157, and other related bugs).
530 // In reality, though, unblocking these signals is really a nop, since
531 // these signals are not blocked by default.
532 sigemptyset(&unblocked_sigs);
533 sigaddset(&unblocked_sigs, SIGILL);
534 sigaddset(&unblocked_sigs, SIGSEGV);
535 sigaddset(&unblocked_sigs, SIGBUS);
536 sigaddset(&unblocked_sigs, SIGFPE);
537 #if defined(PPC64)
538 sigaddset(&unblocked_sigs, SIGTRAP);
539 #endif
540 sigaddset(&unblocked_sigs, SR_signum);
541
542 if (!ReduceSignalUsage) {
543 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
544 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
545 }
546 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
547 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
548 }
549 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
550 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
551 }
552 }
553 // Fill in signals that are blocked by all but the VM thread.
554 sigemptyset(&vm_sigs);
555 if (!ReduceSignalUsage) {
556 sigaddset(&vm_sigs, BREAK_SIGNAL);
557 }
558 debug_only(signal_sets_initialized = true);
559
560 }
561
562 // These are signals that are unblocked while a thread is running Java.
563 // (For some reason, they get blocked by default.)
564 sigset_t* os::Linux::unblocked_signals() {
565 assert(signal_sets_initialized, "Not initialized");
566 return &unblocked_sigs;
567 }
568
569 // These are the signals that are blocked while a (non-VM) thread is
570 // running Java. Only the VM thread handles these signals.
571 sigset_t* os::Linux::vm_signals() {
572 assert(signal_sets_initialized, "Not initialized");
573 return &vm_sigs;
574 }
575
576 void os::Linux::hotspot_sigmask(Thread* thread) {
577
578 //Save caller's signal mask before setting VM signal mask
579 sigset_t caller_sigmask;
580 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
581
582 OSThread* osthread = thread->osthread();
583 osthread->set_caller_sigmask(caller_sigmask);
584
585 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
586
587 if (!ReduceSignalUsage) {
588 if (thread->is_VM_thread()) {
589 // Only the VM thread handles BREAK_SIGNAL ...
590 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
591 } else {
592 // ... all other threads block BREAK_SIGNAL
593 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
594 }
595 }
596 }
597
598 //////////////////////////////////////////////////////////////////////////////
599 // detecting pthread library
600
601 void os::Linux::libpthread_init() {
602 // Save glibc and pthread version strings.
603 #if !defined(_CS_GNU_LIBC_VERSION) || \
604 !defined(_CS_GNU_LIBPTHREAD_VERSION)
605 #error "glibc too old (< 2.3.2)"
606 #endif
607
608 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
609 assert(n > 0, "cannot retrieve glibc version");
610 char *str = (char *)malloc(n, mtInternal);
611 confstr(_CS_GNU_LIBC_VERSION, str, n);
612 os::Linux::set_glibc_version(str);
613
614 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
615 assert(n > 0, "cannot retrieve pthread version");
616 str = (char *)malloc(n, mtInternal);
617 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
618 os::Linux::set_libpthread_version(str);
619 }
620
621 /////////////////////////////////////////////////////////////////////////////
622 // thread stack expansion
623
624 // os::Linux::manually_expand_stack() takes care of expanding the thread
625 // stack. Note that this is normally not needed: pthread stacks allocate
626 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
627 // committed. Therefore it is not necessary to expand the stack manually.
628 //
629 // Manually expanding the stack was historically needed on LinuxThreads
630 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
631 // it is kept to deal with very rare corner cases:
632 //
633 // For one, user may run the VM on an own implementation of threads
634 // whose stacks are - like the old LinuxThreads - implemented using
635 // mmap(MAP_GROWSDOWN).
636 //
637 // Also, this coding may be needed if the VM is running on the primordial
638 // thread. Normally we avoid running on the primordial thread; however,
639 // user may still invoke the VM on the primordial thread.
640 //
641 // The following historical comment describes the details about running
642 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
643
644
645 // Force Linux kernel to expand current thread stack. If "bottom" is close
646 // to the stack guard, caller should block all signals.
647 //
648 // MAP_GROWSDOWN:
649 // A special mmap() flag that is used to implement thread stacks. It tells
650 // kernel that the memory region should extend downwards when needed. This
651 // allows early versions of LinuxThreads to only mmap the first few pages
652 // when creating a new thread. Linux kernel will automatically expand thread
653 // stack as needed (on page faults).
654 //
655 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
656 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
657 // region, it's hard to tell if the fault is due to a legitimate stack
658 // access or because of reading/writing non-exist memory (e.g. buffer
659 // overrun). As a rule, if the fault happens below current stack pointer,
660 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
661 // application (see Linux kernel fault.c).
662 //
663 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
664 // stack overflow detection.
665 //
666 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
667 // not use MAP_GROWSDOWN.
668 //
669 // To get around the problem and allow stack banging on Linux, we need to
670 // manually expand thread stack after receiving the SIGSEGV.
671 //
672 // There are two ways to expand thread stack to address "bottom", we used
673 // both of them in JVM before 1.5:
674 // 1. adjust stack pointer first so that it is below "bottom", and then
675 // touch "bottom"
676 // 2. mmap() the page in question
677 //
678 // Now alternate signal stack is gone, it's harder to use 2. For instance,
679 // if current sp is already near the lower end of page 101, and we need to
680 // call mmap() to map page 100, it is possible that part of the mmap() frame
681 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
682 // That will destroy the mmap() frame and cause VM to crash.
683 //
684 // The following code works by adjusting sp first, then accessing the "bottom"
685 // page to force a page fault. Linux kernel will then automatically expand the
686 // stack mapping.
687 //
688 // _expand_stack_to() assumes its frame size is less than page size, which
689 // should always be true if the function is not inlined.
690
691 static void NOINLINE _expand_stack_to(address bottom) {
692 address sp;
693 size_t size;
694 volatile char *p;
695
696 // Adjust bottom to point to the largest address within the same page, it
697 // gives us a one-page buffer if alloca() allocates slightly more memory.
698 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
699 bottom += os::Linux::page_size() - 1;
700
701 // sp might be slightly above current stack pointer; if that's the case, we
702 // will alloca() a little more space than necessary, which is OK. Don't use
703 // os::current_stack_pointer(), as its result can be slightly below current
704 // stack pointer, causing us to not alloca enough to reach "bottom".
705 sp = (address)&sp;
706
707 if (sp > bottom) {
708 size = sp - bottom;
709 p = (volatile char *)alloca(size);
710 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
711 p[0] = '\0';
712 }
713 }
714
715 void os::Linux::expand_stack_to(address bottom) {
716 _expand_stack_to(bottom);
717 }
718
719 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
720 assert(t!=NULL, "just checking");
721 assert(t->osthread()->expanding_stack(), "expand should be set");
722
723 if (t->is_in_usable_stack(addr)) {
724 sigset_t mask_all, old_sigset;
725 sigfillset(&mask_all);
726 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
727 _expand_stack_to(addr);
728 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
729 return true;
730 }
731 return false;
732 }
733
734 //////////////////////////////////////////////////////////////////////////////
735 // create new thread
736
737 // Thread start routine for all newly created threads
738 static void *thread_native_entry(Thread *thread) {
739
740 thread->record_stack_base_and_size();
741
742 // Try to randomize the cache line index of hot stack frames.
743 // This helps when threads of the same stack traces evict each other's
744 // cache lines. The threads can be either from the same JVM instance, or
745 // from different JVM instances. The benefit is especially true for
746 // processors with hyperthreading technology.
747 static int counter = 0;
748 int pid = os::current_process_id();
749 alloca(((pid ^ counter++) & 7) * 128);
750
751 thread->initialize_thread_current();
752
753 OSThread* osthread = thread->osthread();
754 Monitor* sync = osthread->startThread_lock();
755
756 osthread->set_thread_id(os::current_thread_id());
757
758 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
759 os::current_thread_id(), (uintx) pthread_self());
760
761 if (UseNUMA) {
762 int lgrp_id = os::numa_get_group_id();
763 if (lgrp_id != -1) {
764 thread->set_lgrp_id(lgrp_id);
765 }
766 }
767 // initialize signal mask for this thread
768 os::Linux::hotspot_sigmask(thread);
769
770 // initialize floating point control register
771 os::Linux::init_thread_fpu_state();
772
773 // handshaking with parent thread
774 {
775 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
776
777 // notify parent thread
778 osthread->set_state(INITIALIZED);
779 sync->notify_all();
780
781 // wait until os::start_thread()
782 while (osthread->get_state() == INITIALIZED) {
783 sync->wait_without_safepoint_check();
784 }
785 }
786
787 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
788
789 // call one more level start routine
790 thread->call_run();
791
792 // Note: at this point the thread object may already have deleted itself.
793 // Prevent dereferencing it from here on out.
794 thread = NULL;
795
796 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
797 os::current_thread_id(), (uintx) pthread_self());
798
799 return 0;
800 }
801
802 // On Linux, glibc places static TLS blocks (for __thread variables) on
803 // the thread stack. This decreases the stack size actually available
804 // to threads.
805 //
806 // For large static TLS sizes, this may cause threads to malfunction due
807 // to insufficient stack space. This is a well-known issue in glibc:
808 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
809 //
810 // As a workaround, we call a private but assumed-stable glibc function,
811 // __pthread_get_minstack() to obtain the minstack size and derive the
812 // static TLS size from it. We then increase the user requested stack
813 // size by this TLS size.
814 //
815 // Due to compatibility concerns, this size adjustment is opt-in and
816 // controlled via AdjustStackSizeForTLS.
817 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
818
819 GetMinStack _get_minstack_func = NULL;
820
821 static void get_minstack_init() {
822 _get_minstack_func =
823 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
824 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
825 _get_minstack_func == NULL ? "failed" : "succeeded");
826 }
827
828 // Returns the size of the static TLS area glibc puts on thread stacks.
829 // The value is cached on first use, which occurs when the first thread
830 // is created during VM initialization.
831 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
832 size_t tls_size = 0;
833 if (_get_minstack_func != NULL) {
834 // Obtain the pthread minstack size by calling __pthread_get_minstack.
835 size_t minstack_size = _get_minstack_func(attr);
836
837 // Remove non-TLS area size included in minstack size returned
838 // by __pthread_get_minstack() to get the static TLS size.
839 // In glibc before 2.27, minstack size includes guard_size.
840 // In glibc 2.27 and later, guard_size is automatically added
841 // to the stack size by pthread_create and is no longer included
842 // in minstack size. In both cases, the guard_size is taken into
843 // account, so there is no need to adjust the result for that.
844 //
845 // Although __pthread_get_minstack() is a private glibc function,
846 // it is expected to have a stable behavior across future glibc
847 // versions while glibc still allocates the static TLS blocks off
848 // the stack. Following is glibc 2.28 __pthread_get_minstack():
849 //
850 // size_t
851 // __pthread_get_minstack (const pthread_attr_t *attr)
852 // {
853 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
854 // }
855 //
856 //
857 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
858 // if check is done for precaution.
859 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
860 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
861 }
862 }
863
864 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
865 tls_size);
866 return tls_size;
867 }
868
869 bool os::create_thread(Thread* thread, ThreadType thr_type,
870 size_t req_stack_size) {
871 assert(thread->osthread() == NULL, "caller responsible");
872
873 // Allocate the OSThread object
874 OSThread* osthread = new OSThread(NULL, NULL);
875 if (osthread == NULL) {
876 return false;
877 }
878
879 // set the correct thread state
880 osthread->set_thread_type(thr_type);
881
882 // Initial state is ALLOCATED but not INITIALIZED
883 osthread->set_state(ALLOCATED);
884
885 thread->set_osthread(osthread);
886
887 // init thread attributes
888 pthread_attr_t attr;
889 pthread_attr_init(&attr);
890 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
891
892 // Calculate stack size if it's not specified by caller.
893 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
894 // In glibc versions prior to 2.7 the guard size mechanism
895 // is not implemented properly. The posix standard requires adding
896 // the size of the guard pages to the stack size, instead Linux
897 // takes the space out of 'stacksize'. Thus we adapt the requested
898 // stack_size by the size of the guard pages to mimick proper
899 // behaviour. However, be careful not to end up with a size
900 // of zero due to overflow. Don't add the guard page in that case.
901 size_t guard_size = os::Linux::default_guard_size(thr_type);
902 // Configure glibc guard page. Must happen before calling
903 // get_static_tls_area_size(), which uses the guard_size.
904 pthread_attr_setguardsize(&attr, guard_size);
905
906 size_t stack_adjust_size = 0;
907 if (AdjustStackSizeForTLS) {
908 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
909 stack_adjust_size += get_static_tls_area_size(&attr);
910 } else {
911 stack_adjust_size += guard_size;
912 }
913
914 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
915 if (stack_size <= SIZE_MAX - stack_adjust_size) {
916 stack_size += stack_adjust_size;
917 }
918 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
919
920 int status = pthread_attr_setstacksize(&attr, stack_size);
921 assert_status(status == 0, status, "pthread_attr_setstacksize");
922
923 ThreadState state;
924
925 {
926 pthread_t tid;
927 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
928
929 char buf[64];
930 if (ret == 0) {
931 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
932 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
933 } else {
934 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
935 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
936 // Log some OS information which might explain why creating the thread failed.
937 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
938 LogStream st(Log(os, thread)::info());
939 os::Posix::print_rlimit_info(&st);
940 os::print_memory_info(&st);
941 os::Linux::print_proc_sys_info(&st);
942 os::Linux::print_container_info(&st);
943 }
944
945 pthread_attr_destroy(&attr);
946
947 if (ret != 0) {
948 // Need to clean up stuff we've allocated so far
949 thread->set_osthread(NULL);
950 delete osthread;
951 return false;
952 }
953
954 // Store pthread info into the OSThread
955 osthread->set_pthread_id(tid);
956
957 // Wait until child thread is either initialized or aborted
958 {
959 Monitor* sync_with_child = osthread->startThread_lock();
960 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
961 while ((state = osthread->get_state()) == ALLOCATED) {
962 sync_with_child->wait_without_safepoint_check();
963 }
964 }
965 }
966
967 // Aborted due to thread limit being reached
968 if (state == ZOMBIE) {
969 thread->set_osthread(NULL);
970 delete osthread;
971 return false;
972 }
973
974 // The thread is returned suspended (in state INITIALIZED),
975 // and is started higher up in the call chain
976 assert(state == INITIALIZED, "race condition");
977 return true;
978 }
979
980 /////////////////////////////////////////////////////////////////////////////
981 // attach existing thread
982
983 // bootstrap the main thread
984 bool os::create_main_thread(JavaThread* thread) {
985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
986 return create_attached_thread(thread);
987 }
988
989 bool os::create_attached_thread(JavaThread* thread) {
990 #ifdef ASSERT
991 thread->verify_not_published();
992 #endif
993
994 // Allocate the OSThread object
995 OSThread* osthread = new OSThread(NULL, NULL);
996
997 if (osthread == NULL) {
998 return false;
999 }
1000
1001 // Store pthread info into the OSThread
1002 osthread->set_thread_id(os::Linux::gettid());
1003 osthread->set_pthread_id(::pthread_self());
1004
1005 // initialize floating point control register
1006 os::Linux::init_thread_fpu_state();
1007
1008 // Initial thread state is RUNNABLE
1009 osthread->set_state(RUNNABLE);
1010
1011 thread->set_osthread(osthread);
1012
1013 if (UseNUMA) {
1014 int lgrp_id = os::numa_get_group_id();
1015 if (lgrp_id != -1) {
1016 thread->set_lgrp_id(lgrp_id);
1017 }
1018 }
1019
1020 if (os::is_primordial_thread()) {
1021 // If current thread is primordial thread, its stack is mapped on demand,
1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1023 // the entire stack region to avoid SEGV in stack banging.
1024 // It is also useful to get around the heap-stack-gap problem on SuSE
1025 // kernel (see 4821821 for details). We first expand stack to the top
1026 // of yellow zone, then enable stack yellow zone (order is significant,
1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1028 // is no gap between the last two virtual memory regions.
1029
1030 JavaThread *jt = (JavaThread *)thread;
1031 address addr = jt->stack_reserved_zone_base();
1032 assert(addr != NULL, "initialization problem?");
1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1034
1035 osthread->set_expanding_stack();
1036 os::Linux::manually_expand_stack(jt, addr);
1037 osthread->clear_expanding_stack();
1038 }
1039
1040 // initialize signal mask for this thread
1041 // and save the caller's signal mask
1042 os::Linux::hotspot_sigmask(thread);
1043
1044 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
1045 os::current_thread_id(), (uintx) pthread_self());
1046
1047 return true;
1048 }
1049
1050 void os::pd_start_thread(Thread* thread) {
1051 OSThread * osthread = thread->osthread();
1052 assert(osthread->get_state() != INITIALIZED, "just checking");
1053 Monitor* sync_with_child = osthread->startThread_lock();
1054 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1055 sync_with_child->notify();
1056 }
1057
1058 // Free Linux resources related to the OSThread
1059 void os::free_thread(OSThread* osthread) {
1060 assert(osthread != NULL, "osthread not set");
1061
1062 // We are told to free resources of the argument thread,
1063 // but we can only really operate on the current thread.
1064 assert(Thread::current()->osthread() == osthread,
1065 "os::free_thread but not current thread");
1066
1067 #ifdef ASSERT
1068 sigset_t current;
1069 sigemptyset(¤t);
1070 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1071 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
1072 #endif
1073
1074 // Restore caller's signal mask
1075 sigset_t sigmask = osthread->caller_sigmask();
1076 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1077
1078 delete osthread;
1079 }
1080
1081 //////////////////////////////////////////////////////////////////////////////
1082 // primordial thread
1083
1084 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1085 bool os::is_primordial_thread(void) {
1086 if (suppress_primordial_thread_resolution) {
1087 return false;
1088 }
1089 char dummy;
1090 // If called before init complete, thread stack bottom will be null.
1091 // Can be called if fatal error occurs before initialization.
1092 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1093 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1094 os::Linux::initial_thread_stack_size() != 0,
1095 "os::init did not locate primordial thread's stack region");
1096 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1097 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1098 os::Linux::initial_thread_stack_size()) {
1099 return true;
1100 } else {
1101 return false;
1102 }
1103 }
1104
1105 // Find the virtual memory area that contains addr
1106 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1107 FILE *fp = fopen("/proc/self/maps", "r");
1108 if (fp) {
1109 address low, high;
1110 while (!feof(fp)) {
1111 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1112 if (low <= addr && addr < high) {
1113 if (vma_low) *vma_low = low;
1114 if (vma_high) *vma_high = high;
1115 fclose(fp);
1116 return true;
1117 }
1118 }
1119 for (;;) {
1120 int ch = fgetc(fp);
1121 if (ch == EOF || ch == (int)'\n') break;
1122 }
1123 }
1124 fclose(fp);
1125 }
1126 return false;
1127 }
1128
1129 // Locate primordial thread stack. This special handling of primordial thread stack
1130 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1131 // bogus value for the primordial process thread. While the launcher has created
1132 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1133 // JNI invocation API from a primordial thread.
1134 void os::Linux::capture_initial_stack(size_t max_size) {
1135
1136 // max_size is either 0 (which means accept OS default for thread stacks) or
1137 // a user-specified value known to be at least the minimum needed. If we
1138 // are actually on the primordial thread we can make it appear that we have a
1139 // smaller max_size stack by inserting the guard pages at that location. But we
1140 // cannot do anything to emulate a larger stack than what has been provided by
1141 // the OS or threading library. In fact if we try to use a stack greater than
1142 // what is set by rlimit then we will crash the hosting process.
1143
1144 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1145 // If this is "unlimited" then it will be a huge value.
1146 struct rlimit rlim;
1147 getrlimit(RLIMIT_STACK, &rlim);
1148 size_t stack_size = rlim.rlim_cur;
1149
1150 // 6308388: a bug in ld.so will relocate its own .data section to the
1151 // lower end of primordial stack; reduce ulimit -s value a little bit
1152 // so we won't install guard page on ld.so's data section.
1153 // But ensure we don't underflow the stack size - allow 1 page spare
1154 if (stack_size >= (size_t)(3 * page_size())) {
1155 stack_size -= 2 * page_size();
1156 }
1157
1158 // Try to figure out where the stack base (top) is. This is harder.
1159 //
1160 // When an application is started, glibc saves the initial stack pointer in
1161 // a global variable "__libc_stack_end", which is then used by system
1162 // libraries. __libc_stack_end should be pretty close to stack top. The
1163 // variable is available since the very early days. However, because it is
1164 // a private interface, it could disappear in the future.
1165 //
1166 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1167 // to __libc_stack_end, it is very close to stack top, but isn't the real
1168 // stack top. Note that /proc may not exist if VM is running as a chroot
1169 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1170 // /proc/<pid>/stat could change in the future (though unlikely).
1171 //
1172 // We try __libc_stack_end first. If that doesn't work, look for
1173 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1174 // as a hint, which should work well in most cases.
1175
1176 uintptr_t stack_start;
1177
1178 // try __libc_stack_end first
1179 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1180 if (p && *p) {
1181 stack_start = *p;
1182 } else {
1183 // see if we can get the start_stack field from /proc/self/stat
1184 FILE *fp;
1185 int pid;
1186 char state;
1187 int ppid;
1188 int pgrp;
1189 int session;
1190 int nr;
1191 int tpgrp;
1192 unsigned long flags;
1193 unsigned long minflt;
1194 unsigned long cminflt;
1195 unsigned long majflt;
1196 unsigned long cmajflt;
1197 unsigned long utime;
1198 unsigned long stime;
1199 long cutime;
1200 long cstime;
1201 long prio;
1202 long nice;
1203 long junk;
1204 long it_real;
1205 uintptr_t start;
1206 uintptr_t vsize;
1207 intptr_t rss;
1208 uintptr_t rsslim;
1209 uintptr_t scodes;
1210 uintptr_t ecode;
1211 int i;
1212
1213 // Figure what the primordial thread stack base is. Code is inspired
1214 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1215 // followed by command name surrounded by parentheses, state, etc.
1216 char stat[2048];
1217 int statlen;
1218
1219 fp = fopen("/proc/self/stat", "r");
1220 if (fp) {
1221 statlen = fread(stat, 1, 2047, fp);
1222 stat[statlen] = '\0';
1223 fclose(fp);
1224
1225 // Skip pid and the command string. Note that we could be dealing with
1226 // weird command names, e.g. user could decide to rename java launcher
1227 // to "java 1.4.2 :)", then the stat file would look like
1228 // 1234 (java 1.4.2 :)) R ... ...
1229 // We don't really need to know the command string, just find the last
1230 // occurrence of ")" and then start parsing from there. See bug 4726580.
1231 char * s = strrchr(stat, ')');
1232
1233 i = 0;
1234 if (s) {
1235 // Skip blank chars
1236 do { s++; } while (s && isspace(*s));
1237
1238 #define _UFM UINTX_FORMAT
1239 #define _DFM INTX_FORMAT
1240
1241 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1242 // 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
1243 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,
1244 &state, // 3 %c
1245 &ppid, // 4 %d
1246 &pgrp, // 5 %d
1247 &session, // 6 %d
1248 &nr, // 7 %d
1249 &tpgrp, // 8 %d
1250 &flags, // 9 %lu
1251 &minflt, // 10 %lu
1252 &cminflt, // 11 %lu
1253 &majflt, // 12 %lu
1254 &cmajflt, // 13 %lu
1255 &utime, // 14 %lu
1256 &stime, // 15 %lu
1257 &cutime, // 16 %ld
1258 &cstime, // 17 %ld
1259 &prio, // 18 %ld
1260 &nice, // 19 %ld
1261 &junk, // 20 %ld
1262 &it_real, // 21 %ld
1263 &start, // 22 UINTX_FORMAT
1264 &vsize, // 23 UINTX_FORMAT
1265 &rss, // 24 INTX_FORMAT
1266 &rsslim, // 25 UINTX_FORMAT
1267 &scodes, // 26 UINTX_FORMAT
1268 &ecode, // 27 UINTX_FORMAT
1269 &stack_start); // 28 UINTX_FORMAT
1270 }
1271
1272 #undef _UFM
1273 #undef _DFM
1274
1275 if (i != 28 - 2) {
1276 assert(false, "Bad conversion from /proc/self/stat");
1277 // product mode - assume we are the primordial thread, good luck in the
1278 // embedded case.
1279 warning("Can't detect primordial thread stack location - bad conversion");
1280 stack_start = (uintptr_t) &rlim;
1281 }
1282 } else {
1283 // For some reason we can't open /proc/self/stat (for example, running on
1284 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1285 // most cases, so don't abort:
1286 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1287 stack_start = (uintptr_t) &rlim;
1288 }
1289 }
1290
1291 // Now we have a pointer (stack_start) very close to the stack top, the
1292 // next thing to do is to figure out the exact location of stack top. We
1293 // can find out the virtual memory area that contains stack_start by
1294 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1295 // and its upper limit is the real stack top. (again, this would fail if
1296 // running inside chroot, because /proc may not exist.)
1297
1298 uintptr_t stack_top;
1299 address low, high;
1300 if (find_vma((address)stack_start, &low, &high)) {
1301 // success, "high" is the true stack top. (ignore "low", because initial
1302 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1303 stack_top = (uintptr_t)high;
1304 } else {
1305 // failed, likely because /proc/self/maps does not exist
1306 warning("Can't detect primordial thread stack location - find_vma failed");
1307 // best effort: stack_start is normally within a few pages below the real
1308 // stack top, use it as stack top, and reduce stack size so we won't put
1309 // guard page outside stack.
1310 stack_top = stack_start;
1311 stack_size -= 16 * page_size();
1312 }
1313
1314 // stack_top could be partially down the page so align it
1315 stack_top = align_up(stack_top, page_size());
1316
1317 // Allowed stack value is minimum of max_size and what we derived from rlimit
1318 if (max_size > 0) {
1319 _initial_thread_stack_size = MIN2(max_size, stack_size);
1320 } else {
1321 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1322 // clamp it at 8MB as we do on Solaris
1323 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1324 }
1325 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1326 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1327
1328 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1329
1330 if (log_is_enabled(Info, os, thread)) {
1331 // See if we seem to be on primordial process thread
1332 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1333 uintptr_t(&rlim) < stack_top;
1334
1335 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1336 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1337 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1338 stack_top, intptr_t(_initial_thread_stack_bottom));
1339 }
1340 }
1341
1342 ////////////////////////////////////////////////////////////////////////////////
1343 // time support
1344
1345 #ifndef SUPPORTS_CLOCK_MONOTONIC
1346 #error "Build platform doesn't support clock_gettime and related functionality"
1347 #endif
1348
1349 // Time since start-up in seconds to a fine granularity.
1350 // Used by VMSelfDestructTimer and the MemProfiler.
1351 double os::elapsedTime() {
1352
1353 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1354 }
1355
1356 jlong os::elapsed_counter() {
1357 return javaTimeNanos() - initial_time_count;
1358 }
1359
1360 jlong os::elapsed_frequency() {
1361 return NANOSECS_PER_SEC; // nanosecond resolution
1362 }
1363
1364 bool os::supports_vtime() { return true; }
1365
1366 double os::elapsedVTime() {
1367 struct rusage usage;
1368 int retval = getrusage(RUSAGE_THREAD, &usage);
1369 if (retval == 0) {
1370 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);
1371 } else {
1372 // better than nothing, but not much
1373 return elapsedTime();
1374 }
1375 }
1376
1377 jlong os::javaTimeMillis() {
1378 timeval time;
1379 int status = gettimeofday(&time, NULL);
1380 assert(status != -1, "linux error");
1381 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1382 }
1383
1384 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1385 timeval time;
1386 int status = gettimeofday(&time, NULL);
1387 assert(status != -1, "linux error");
1388 seconds = jlong(time.tv_sec);
1389 nanos = jlong(time.tv_usec) * 1000;
1390 }
1391
1392 void os::Linux::fast_thread_clock_init() {
1393 if (!UseLinuxPosixThreadCPUClocks) {
1394 return;
1395 }
1396 clockid_t clockid;
1397 struct timespec tp;
1398 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1399 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1400
1401 // Switch to using fast clocks for thread cpu time if
1402 // the clock_getres() returns 0 error code.
1403 // Note, that some kernels may support the current thread
1404 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1405 // returned by the pthread_getcpuclockid().
1406 // If the fast Posix clocks are supported then the clock_getres()
1407 // must return at least tp.tv_sec == 0 which means a resolution
1408 // better than 1 sec. This is extra check for reliability.
1409
1410 if (pthread_getcpuclockid_func &&
1411 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1412 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1413 _supports_fast_thread_cpu_time = true;
1414 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1415 }
1416 }
1417
1418 jlong os::javaTimeNanos() {
1419 if (os::supports_monotonic_clock()) {
1420 struct timespec tp;
1421 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1422 assert(status == 0, "gettime error");
1423 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1424 return result;
1425 } else {
1426 timeval time;
1427 int status = gettimeofday(&time, NULL);
1428 assert(status != -1, "linux error");
1429 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1430 return 1000 * usecs;
1431 }
1432 }
1433
1434 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1435 if (os::supports_monotonic_clock()) {
1436 info_ptr->max_value = ALL_64_BITS;
1437
1438 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1439 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1440 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1441 } else {
1442 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1443 info_ptr->max_value = ALL_64_BITS;
1444
1445 // gettimeofday is a real time clock so it skips
1446 info_ptr->may_skip_backward = true;
1447 info_ptr->may_skip_forward = true;
1448 }
1449
1450 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1451 }
1452
1453 // Return the real, user, and system times in seconds from an
1454 // arbitrary fixed point in the past.
1455 bool os::getTimesSecs(double* process_real_time,
1456 double* process_user_time,
1457 double* process_system_time) {
1458 struct tms ticks;
1459 clock_t real_ticks = times(&ticks);
1460
1461 if (real_ticks == (clock_t) (-1)) {
1462 return false;
1463 } else {
1464 double ticks_per_second = (double) clock_tics_per_sec;
1465 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1466 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1467 *process_real_time = ((double) real_ticks) / ticks_per_second;
1468
1469 return true;
1470 }
1471 }
1472
1473
1474 char * os::local_time_string(char *buf, size_t buflen) {
1475 struct tm t;
1476 time_t long_time;
1477 time(&long_time);
1478 localtime_r(&long_time, &t);
1479 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1480 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1481 t.tm_hour, t.tm_min, t.tm_sec);
1482 return buf;
1483 }
1484
1485 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1486 return localtime_r(clock, res);
1487 }
1488
1489 ////////////////////////////////////////////////////////////////////////////////
1490 // runtime exit support
1491
1492 // Note: os::shutdown() might be called very early during initialization, or
1493 // called from signal handler. Before adding something to os::shutdown(), make
1494 // sure it is async-safe and can handle partially initialized VM.
1495 void os::shutdown() {
1496
1497 // allow PerfMemory to attempt cleanup of any persistent resources
1498 perfMemory_exit();
1499
1500 // needs to remove object in file system
1501 AttachListener::abort();
1502
1503 // flush buffered output, finish log files
1504 ostream_abort();
1505
1506 // Check for abort hook
1507 abort_hook_t abort_hook = Arguments::abort_hook();
1508 if (abort_hook != NULL) {
1509 abort_hook();
1510 }
1511
1512 }
1513
1514 // Note: os::abort() might be called very early during initialization, or
1515 // called from signal handler. Before adding something to os::abort(), make
1516 // sure it is async-safe and can handle partially initialized VM.
1517 void os::abort(bool dump_core, void* siginfo, const void* context) {
1518 os::shutdown();
1519 if (dump_core) {
1520 if (DumpPrivateMappingsInCore) {
1521 ClassLoader::close_jrt_image();
1522 }
1523 #ifndef PRODUCT
1524 fdStream out(defaultStream::output_fd());
1525 out.print_raw("Current thread is ");
1526 char buf[16];
1527 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1528 out.print_raw_cr(buf);
1529 out.print_raw_cr("Dumping core ...");
1530 #endif
1531 ::abort(); // dump core
1532 }
1533
1534 ::exit(1);
1535 }
1536
1537 // Die immediately, no exit hook, no abort hook, no cleanup.
1538 // Dump a core file, if possible, for debugging.
1539 void os::die() {
1540 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1541 // For TimeoutInErrorHandlingTest.java, we just kill the VM
1542 // and don't take the time to generate a core file.
1543 os::signal_raise(SIGKILL);
1544 } else {
1545 ::abort();
1546 }
1547 }
1548
1549 // thread_id is kernel thread id (similar to Solaris LWP id)
1550 intx os::current_thread_id() { return os::Linux::gettid(); }
1551 int os::current_process_id() {
1552 return ::getpid();
1553 }
1554
1555 // DLL functions
1556
1557 const char* os::dll_file_extension() { return ".so"; }
1558
1559 // This must be hard coded because it's the system's temporary
1560 // directory not the java application's temp directory, ala java.io.tmpdir.
1561 const char* os::get_temp_directory() { return "/tmp"; }
1562
1563 static bool file_exists(const char* filename) {
1564 struct stat statbuf;
1565 if (filename == NULL || strlen(filename) == 0) {
1566 return false;
1567 }
1568 return os::stat(filename, &statbuf) == 0;
1569 }
1570
1571 // check if addr is inside libjvm.so
1572 bool os::address_is_in_vm(address addr) {
1573 static address libjvm_base_addr;
1574 Dl_info dlinfo;
1575
1576 if (libjvm_base_addr == NULL) {
1577 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1578 libjvm_base_addr = (address)dlinfo.dli_fbase;
1579 }
1580 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1581 }
1582
1583 if (dladdr((void *)addr, &dlinfo) != 0) {
1584 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1585 }
1586
1587 return false;
1588 }
1589
1590 bool os::dll_address_to_function_name(address addr, char *buf,
1591 int buflen, int *offset,
1592 bool demangle) {
1593 // buf is not optional, but offset is optional
1594 assert(buf != NULL, "sanity check");
1595
1596 Dl_info dlinfo;
1597
1598 if (dladdr((void*)addr, &dlinfo) != 0) {
1599 // see if we have a matching symbol
1600 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1601 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1602 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1603 }
1604 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1605 return true;
1606 }
1607 // no matching symbol so try for just file info
1608 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1609 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1610 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1611 return true;
1612 }
1613 }
1614 }
1615
1616 buf[0] = '\0';
1617 if (offset != NULL) *offset = -1;
1618 return false;
1619 }
1620
1621 struct _address_to_library_name {
1622 address addr; // input : memory address
1623 size_t buflen; // size of fname
1624 char* fname; // output: library name
1625 address base; // library base addr
1626 };
1627
1628 static int address_to_library_name_callback(struct dl_phdr_info *info,
1629 size_t size, void *data) {
1630 int i;
1631 bool found = false;
1632 address libbase = NULL;
1633 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1634
1635 // iterate through all loadable segments
1636 for (i = 0; i < info->dlpi_phnum; i++) {
1637 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1638 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1639 // base address of a library is the lowest address of its loaded
1640 // segments.
1641 if (libbase == NULL || libbase > segbase) {
1642 libbase = segbase;
1643 }
1644 // see if 'addr' is within current segment
1645 if (segbase <= d->addr &&
1646 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1647 found = true;
1648 }
1649 }
1650 }
1651
1652 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1653 // so dll_address_to_library_name() can fall through to use dladdr() which
1654 // can figure out executable name from argv[0].
1655 if (found && info->dlpi_name && info->dlpi_name[0]) {
1656 d->base = libbase;
1657 if (d->fname) {
1658 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1659 }
1660 return 1;
1661 }
1662 return 0;
1663 }
1664
1665 bool os::dll_address_to_library_name(address addr, char* buf,
1666 int buflen, int* offset) {
1667 // buf is not optional, but offset is optional
1668 assert(buf != NULL, "sanity check");
1669
1670 Dl_info dlinfo;
1671 struct _address_to_library_name data;
1672
1673 // There is a bug in old glibc dladdr() implementation that it could resolve
1674 // to wrong library name if the .so file has a base address != NULL. Here
1675 // we iterate through the program headers of all loaded libraries to find
1676 // out which library 'addr' really belongs to. This workaround can be
1677 // removed once the minimum requirement for glibc is moved to 2.3.x.
1678 data.addr = addr;
1679 data.fname = buf;
1680 data.buflen = buflen;
1681 data.base = NULL;
1682 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1683
1684 if (rslt) {
1685 // buf already contains library name
1686 if (offset) *offset = addr - data.base;
1687 return true;
1688 }
1689 if (dladdr((void*)addr, &dlinfo) != 0) {
1690 if (dlinfo.dli_fname != NULL) {
1691 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1692 }
1693 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1694 *offset = addr - (address)dlinfo.dli_fbase;
1695 }
1696 return true;
1697 }
1698
1699 buf[0] = '\0';
1700 if (offset) *offset = -1;
1701 return false;
1702 }
1703
1704 // Loads .dll/.so and
1705 // in case of error it checks if .dll/.so was built for the
1706 // same architecture as Hotspot is running on
1707
1708
1709 // Remember the stack's state. The Linux dynamic linker will change
1710 // the stack to 'executable' at most once, so we must safepoint only once.
1711 bool os::Linux::_stack_is_executable = false;
1712
1713 // VM operation that loads a library. This is necessary if stack protection
1714 // of the Java stacks can be lost during loading the library. If we
1715 // do not stop the Java threads, they can stack overflow before the stacks
1716 // are protected again.
1717 class VM_LinuxDllLoad: public VM_Operation {
1718 private:
1719 const char *_filename;
1720 char *_ebuf;
1721 int _ebuflen;
1722 void *_lib;
1723 public:
1724 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1725 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1726 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1727 void doit() {
1728 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1729 os::Linux::_stack_is_executable = true;
1730 }
1731 void* loaded_library() { return _lib; }
1732 };
1733
1734 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1735 void * result = NULL;
1736 bool load_attempted = false;
1737
1738 log_info(os)("attempting shared library load of %s", filename);
1739
1740 // Check whether the library to load might change execution rights
1741 // of the stack. If they are changed, the protection of the stack
1742 // guard pages will be lost. We need a safepoint to fix this.
1743 //
1744 // See Linux man page execstack(8) for more info.
1745 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1746 if (!ElfFile::specifies_noexecstack(filename)) {
1747 if (!is_init_completed()) {
1748 os::Linux::_stack_is_executable = true;
1749 // This is OK - No Java threads have been created yet, and hence no
1750 // stack guard pages to fix.
1751 //
1752 // Dynamic loader will make all stacks executable after
1753 // this function returns, and will not do that again.
1754 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1755 } else {
1756 warning("You have loaded library %s which might have disabled stack guard. "
1757 "The VM will try to fix the stack guard now.\n"
1758 "It's highly recommended that you fix the library with "
1759 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1760 filename);
1761
1762 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1763 JavaThread *jt = JavaThread::current();
1764 if (jt->thread_state() != _thread_in_native) {
1765 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1766 // that requires ExecStack. Cannot enter safe point. Let's give up.
1767 warning("Unable to fix stack guard. Giving up.");
1768 } else {
1769 if (!LoadExecStackDllInVMThread) {
1770 // This is for the case where the DLL has an static
1771 // constructor function that executes JNI code. We cannot
1772 // load such DLLs in the VMThread.
1773 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1774 }
1775
1776 ThreadInVMfromNative tiv(jt);
1777 debug_only(VMNativeEntryWrapper vew;)
1778
1779 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1780 VMThread::execute(&op);
1781 if (LoadExecStackDllInVMThread) {
1782 result = op.loaded_library();
1783 }
1784 load_attempted = true;
1785 }
1786 }
1787 }
1788 }
1789
1790 if (!load_attempted) {
1791 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1792 }
1793
1794 if (result != NULL) {
1795 // Successful loading
1796 return result;
1797 }
1798
1799 Elf32_Ehdr elf_head;
1800 int diag_msg_max_length=ebuflen-strlen(ebuf);
1801 char* diag_msg_buf=ebuf+strlen(ebuf);
1802
1803 if (diag_msg_max_length==0) {
1804 // No more space in ebuf for additional diagnostics message
1805 return NULL;
1806 }
1807
1808
1809 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1810
1811 if (file_descriptor < 0) {
1812 // Can't open library, report dlerror() message
1813 return NULL;
1814 }
1815
1816 bool failed_to_read_elf_head=
1817 (sizeof(elf_head)!=
1818 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1819
1820 ::close(file_descriptor);
1821 if (failed_to_read_elf_head) {
1822 // file i/o error - report dlerror() msg
1823 return NULL;
1824 }
1825
1826 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1827 // handle invalid/out of range endianness values
1828 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1829 return NULL;
1830 }
1831
1832 #if defined(VM_LITTLE_ENDIAN)
1833 // VM is LE, shared object BE
1834 elf_head.e_machine = be16toh(elf_head.e_machine);
1835 #else
1836 // VM is BE, shared object LE
1837 elf_head.e_machine = le16toh(elf_head.e_machine);
1838 #endif
1839 }
1840
1841 typedef struct {
1842 Elf32_Half code; // Actual value as defined in elf.h
1843 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1844 unsigned char elf_class; // 32 or 64 bit
1845 unsigned char endianness; // MSB or LSB
1846 char* name; // String representation
1847 } arch_t;
1848
1849 #ifndef EM_AARCH64
1850 #define EM_AARCH64 183 /* ARM AARCH64 */
1851 #endif
1852 #ifndef EM_RISCV
1853 #define EM_RISCV 243 /* RISC-V */
1854 #endif
1855
1856 static const arch_t arch_array[]={
1857 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1858 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1859 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1860 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1861 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1862 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1863 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1864 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1865 #if defined(VM_LITTLE_ENDIAN)
1866 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1867 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1868 #else
1869 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1870 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1871 #endif
1872 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1873 // we only support 64 bit z architecture
1874 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
1875 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1876 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1877 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1878 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1879 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1880 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1881 {EM_RISCV, EM_RISCV, ELFCLASS64, ELFDATA2LSB, (char*)"RISC-V"},
1882 };
1883
1884 #if (defined IA32)
1885 static Elf32_Half running_arch_code=EM_386;
1886 #elif (defined AMD64) || (defined X32)
1887 static Elf32_Half running_arch_code=EM_X86_64;
1888 #elif (defined IA64)
1889 static Elf32_Half running_arch_code=EM_IA_64;
1890 #elif (defined __sparc) && (defined _LP64)
1891 static Elf32_Half running_arch_code=EM_SPARCV9;
1892 #elif (defined __sparc) && (!defined _LP64)
1893 static Elf32_Half running_arch_code=EM_SPARC;
1894 #elif (defined __powerpc64__)
1895 static Elf32_Half running_arch_code=EM_PPC64;
1896 #elif (defined __powerpc__)
1897 static Elf32_Half running_arch_code=EM_PPC;
1898 #elif (defined AARCH64)
1899 static Elf32_Half running_arch_code=EM_AARCH64;
1900 #elif (defined ARM)
1901 static Elf32_Half running_arch_code=EM_ARM;
1902 #elif (defined S390)
1903 static Elf32_Half running_arch_code=EM_S390;
1904 #elif (defined ALPHA)
1905 static Elf32_Half running_arch_code=EM_ALPHA;
1906 #elif (defined MIPSEL)
1907 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1908 #elif (defined PARISC)
1909 static Elf32_Half running_arch_code=EM_PARISC;
1910 #elif (defined MIPS)
1911 static Elf32_Half running_arch_code=EM_MIPS;
1912 #elif (defined M68K)
1913 static Elf32_Half running_arch_code=EM_68K;
1914 #elif (defined SH)
1915 static Elf32_Half running_arch_code=EM_SH;
1916 #elif (defined RISCV)
1917 static Elf32_Half running_arch_code=EM_RISCV;
1918 #else
1919 #error Method os::dll_load requires that one of following is defined:\
1920 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, RISCV, S390, SH, __sparc
1921 #endif
1922
1923 // Identify compatibility class for VM's architecture and library's architecture
1924 // Obtain string descriptions for architectures
1925
1926 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1927 int running_arch_index=-1;
1928
1929 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1930 if (running_arch_code == arch_array[i].code) {
1931 running_arch_index = i;
1932 }
1933 if (lib_arch.code == arch_array[i].code) {
1934 lib_arch.compat_class = arch_array[i].compat_class;
1935 lib_arch.name = arch_array[i].name;
1936 }
1937 }
1938
1939 assert(running_arch_index != -1,
1940 "Didn't find running architecture code (running_arch_code) in arch_array");
1941 if (running_arch_index == -1) {
1942 // Even though running architecture detection failed
1943 // we may still continue with reporting dlerror() message
1944 return NULL;
1945 }
1946
1947 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1948 if (lib_arch.name != NULL) {
1949 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1950 " (Possible cause: can't load %s .so on a %s platform)",
1951 lib_arch.name, arch_array[running_arch_index].name);
1952 } else {
1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1954 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1955 lib_arch.code, arch_array[running_arch_index].name);
1956 }
1957 return NULL;
1958 }
1959
1960 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1961 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1962 return NULL;
1963 }
1964
1965 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1966 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1967 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1968 return NULL;
1969 }
1970
1971 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1972 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1973 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1974 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1975 return NULL;
1976 }
1977
1978 return NULL;
1979 }
1980
1981 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1982 int ebuflen) {
1983 void * result = ::dlopen(filename, RTLD_LAZY);
1984 if (result == NULL) {
1985 const char* error_report = ::dlerror();
1986 if (error_report == NULL) {
1987 error_report = "dlerror returned no error description";
1988 }
1989 if (ebuf != NULL && ebuflen > 0) {
1990 ::strncpy(ebuf, error_report, ebuflen-1);
1991 ebuf[ebuflen-1]='\0';
1992 }
1993 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1994 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1995 } else {
1996 Events::log(NULL, "Loaded shared library %s", filename);
1997 log_info(os)("shared library load of %s was successful", filename);
1998 }
1999 return result;
2000 }
2001
2002 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
2003 int ebuflen) {
2004 void * result = NULL;
2005 if (LoadExecStackDllInVMThread) {
2006 result = dlopen_helper(filename, ebuf, ebuflen);
2007 }
2008
2009 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2010 // library that requires an executable stack, or which does not have this
2011 // stack attribute set, dlopen changes the stack attribute to executable. The
2012 // read protection of the guard pages gets lost.
2013 //
2014 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2015 // may have been queued at the same time.
2016
2017 if (!_stack_is_executable) {
2018 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2019 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2020 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
2021 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
2022 warning("Attempt to reguard stack yellow zone failed.");
2023 }
2024 }
2025 }
2026 }
2027
2028 return result;
2029 }
2030
2031 void* os::dll_lookup(void* handle, const char* name) {
2032 void* res = dlsym(handle, name);
2033 return res;
2034 }
2035
2036 void* os::get_default_process_handle() {
2037 return (void*)::dlopen(NULL, RTLD_LAZY);
2038 }
2039
2040 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
2041 int fd = ::open(filename, O_RDONLY);
2042 if (fd == -1) {
2043 return false;
2044 }
2045
2046 if (hdr != NULL) {
2047 st->print_cr("%s", hdr);
2048 }
2049
2050 char buf[33];
2051 int bytes;
2052 buf[32] = '\0';
2053 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
2054 st->print_raw(buf, bytes);
2055 }
2056
2057 ::close(fd);
2058
2059 return true;
2060 }
2061
2062 static void _print_ascii_file_h(const char* header, const char* filename, outputStream* st) {
2063 st->print("%s", header);
2064 if (!_print_ascii_file(filename, st)) {
2065 st->print_cr("<Not Available>");
2066 }
2067 }
2068
2069 void os::print_dll_info(outputStream *st) {
2070 st->print_cr("Dynamic libraries:");
2071
2072 char fname[32];
2073 pid_t pid = os::Linux::gettid();
2074
2075 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2076
2077 if (!_print_ascii_file(fname, st)) {
2078 st->print("Can not get library information for pid = %d\n", pid);
2079 }
2080 }
2081
2082 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2083 FILE *procmapsFile = NULL;
2084
2085 // Open the procfs maps file for the current process
2086 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2087 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2088 char line[PATH_MAX + 100];
2089
2090 // Read line by line from 'file'
2091 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2092 u8 base, top, inode;
2093 char name[sizeof(line)];
2094
2095 // Parse fields from line, discard perms, offset and device
2096 int matches = sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %*s %*s %*s " INT64_FORMAT " %s",
2097 &base, &top, &inode, name);
2098 // the last entry 'name' is empty for some entries, so we might have 3 matches instead of 4 for some lines
2099 if (matches < 3) continue;
2100 if (matches == 3) name[0] = '\0';
2101
2102 // Filter by inode 0 so that we only get file system mapped files.
2103 if (inode != 0) {
2104
2105 // Call callback with the fields of interest
2106 if(callback(name, (address)base, (address)top, param)) {
2107 // Oops abort, callback aborted
2108 fclose(procmapsFile);
2109 return 1;
2110 }
2111 }
2112 }
2113 fclose(procmapsFile);
2114 }
2115 return 0;
2116 }
2117
2118 void os::print_os_info_brief(outputStream* st) {
2119 os::Linux::print_distro_info(st);
2120
2121 os::Posix::print_uname_info(st);
2122
2123 os::Linux::print_libversion_info(st);
2124
2125 }
2126
2127 void os::print_os_info(outputStream* st) {
2128 st->print("OS:");
2129
2130 os::Linux::print_distro_info(st);
2131
2132 os::Posix::print_uname_info(st);
2133
2134 os::Linux::print_uptime_info(st);
2135
2136 // Print warning if unsafe chroot environment detected
2137 if (unsafe_chroot_detected) {
2138 st->print("WARNING!! ");
2139 st->print_cr("%s", unstable_chroot_error);
2140 }
2141
2142 os::Linux::print_libversion_info(st);
2143
2144 os::Posix::print_rlimit_info(st);
2145
2146 os::Posix::print_load_average(st);
2147
2148 os::Linux::print_full_memory_info(st);
2149
2150 os::Linux::print_proc_sys_info(st);
2151
2152 os::Linux::print_ld_preload_file(st);
2153
2154 os::Linux::print_container_info(st);
2155
2156 VM_Version::print_platform_virtualization_info(st);
2157
2158 os::Linux::print_steal_info(st);
2159 }
2160
2161 // Try to identify popular distros.
2162 // Most Linux distributions have a /etc/XXX-release file, which contains
2163 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2164 // file that also contains the OS version string. Some have more than one
2165 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2166 // /etc/redhat-release.), so the order is important.
2167 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2168 // their own specific XXX-release file as well as a redhat-release file.
2169 // Because of this the XXX-release file needs to be searched for before the
2170 // redhat-release file.
2171 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2172 // search for redhat-release / SuSE-release needs to be before lsb-release.
2173 // Since the lsb-release file is the new standard it needs to be searched
2174 // before the older style release files.
2175 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2176 // next to last resort. The os-release file is a new standard that contains
2177 // distribution information and the system-release file seems to be an old
2178 // standard that has been replaced by the lsb-release and os-release files.
2179 // Searching for the debian_version file is the last resort. It contains
2180 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2181 // "Debian " is printed before the contents of the debian_version file.
2182
2183 const char* distro_files[] = {
2184 "/etc/oracle-release",
2185 "/etc/mandriva-release",
2186 "/etc/mandrake-release",
2187 "/etc/sun-release",
2188 "/etc/redhat-release",
2189 "/etc/SuSE-release",
2190 "/etc/lsb-release",
2191 "/etc/turbolinux-release",
2192 "/etc/gentoo-release",
2193 "/etc/ltib-release",
2194 "/etc/angstrom-version",
2195 "/etc/system-release",
2196 "/etc/os-release",
2197 NULL };
2198
2199 void os::Linux::print_distro_info(outputStream* st) {
2200 for (int i = 0;; i++) {
2201 const char* file = distro_files[i];
2202 if (file == NULL) {
2203 break; // done
2204 }
2205 // If file prints, we found it.
2206 if (_print_ascii_file(file, st)) {
2207 return;
2208 }
2209 }
2210
2211 if (file_exists("/etc/debian_version")) {
2212 st->print("Debian ");
2213 _print_ascii_file("/etc/debian_version", st);
2214 } else {
2215 st->print("Linux");
2216 }
2217 st->cr();
2218 }
2219
2220 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2221 char buf[256];
2222 while (fgets(buf, sizeof(buf), fp)) {
2223 // Edit out extra stuff in expected format
2224 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2225 char* ptr = strstr(buf, "\""); // the name is in quotes
2226 if (ptr != NULL) {
2227 ptr++; // go beyond first quote
2228 char* nl = strchr(ptr, '\"');
2229 if (nl != NULL) *nl = '\0';
2230 strncpy(distro, ptr, length);
2231 } else {
2232 ptr = strstr(buf, "=");
2233 ptr++; // go beyond equals then
2234 char* nl = strchr(ptr, '\n');
2235 if (nl != NULL) *nl = '\0';
2236 strncpy(distro, ptr, length);
2237 }
2238 return;
2239 } else if (get_first_line) {
2240 char* nl = strchr(buf, '\n');
2241 if (nl != NULL) *nl = '\0';
2242 strncpy(distro, buf, length);
2243 return;
2244 }
2245 }
2246 // print last line and close
2247 char* nl = strchr(buf, '\n');
2248 if (nl != NULL) *nl = '\0';
2249 strncpy(distro, buf, length);
2250 }
2251
2252 static void parse_os_info(char* distro, size_t length, const char* file) {
2253 FILE* fp = fopen(file, "r");
2254 if (fp != NULL) {
2255 // if suse format, print out first line
2256 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2257 parse_os_info_helper(fp, distro, length, get_first_line);
2258 fclose(fp);
2259 }
2260 }
2261
2262 void os::get_summary_os_info(char* buf, size_t buflen) {
2263 for (int i = 0;; i++) {
2264 const char* file = distro_files[i];
2265 if (file == NULL) {
2266 break; // ran out of distro_files
2267 }
2268 if (file_exists(file)) {
2269 parse_os_info(buf, buflen, file);
2270 return;
2271 }
2272 }
2273 // special case for debian
2274 if (file_exists("/etc/debian_version")) {
2275 strncpy(buf, "Debian ", buflen);
2276 if (buflen > 7) {
2277 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2278 }
2279 } else {
2280 strncpy(buf, "Linux", buflen);
2281 }
2282 }
2283
2284 void os::Linux::print_libversion_info(outputStream* st) {
2285 // libc, pthread
2286 st->print("libc:");
2287 st->print("%s ", os::Linux::glibc_version());
2288 st->print("%s ", os::Linux::libpthread_version());
2289 st->cr();
2290 }
2291
2292 void os::Linux::print_proc_sys_info(outputStream* st) {
2293 st->cr();
2294 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
2295 _print_ascii_file("/proc/sys/kernel/threads-max", st);
2296 st->cr();
2297 st->cr();
2298
2299 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
2300 _print_ascii_file("/proc/sys/vm/max_map_count", st);
2301 st->cr();
2302 st->cr();
2303
2304 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
2305 _print_ascii_file("/proc/sys/kernel/pid_max", st);
2306 st->cr();
2307 st->cr();
2308 }
2309
2310 void os::Linux::print_full_memory_info(outputStream* st) {
2311 st->print("\n/proc/meminfo:\n");
2312 _print_ascii_file("/proc/meminfo", st);
2313 st->cr();
2314
2315 // some information regarding THPs; for details see
2316 // https://www.kernel.org/doc/Documentation/vm/transhuge.txt
2317 st->print_cr("/sys/kernel/mm/transparent_hugepage/enabled:");
2318 if (!_print_ascii_file("/sys/kernel/mm/transparent_hugepage/enabled", st)) {
2319 st->print_cr(" <Not Available>");
2320 }
2321 st->cr();
2322 st->print_cr("/sys/kernel/mm/transparent_hugepage/defrag (defrag/compaction efforts parameter):");
2323 if (!_print_ascii_file("/sys/kernel/mm/transparent_hugepage/defrag", st)) {
2324 st->print_cr(" <Not Available>");
2325 }
2326 st->cr();
2327 }
2328
2329 void os::Linux::print_ld_preload_file(outputStream* st) {
2330 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2331 st->cr();
2332 }
2333
2334 void os::Linux::print_uptime_info(outputStream* st) {
2335 struct sysinfo sinfo;
2336 int ret = sysinfo(&sinfo);
2337 if (ret == 0) {
2338 os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
2339 }
2340 }
2341
2342
2343 void os::Linux::print_container_info(outputStream* st) {
2344 if (!OSContainer::is_containerized()) {
2345 return;
2346 }
2347
2348 st->print("container (cgroup) information:\n");
2349
2350 const char *p_ct = OSContainer::container_type();
2351 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2352
2353 char *p = OSContainer::cpu_cpuset_cpus();
2354 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2355 free(p);
2356
2357 p = OSContainer::cpu_cpuset_memory_nodes();
2358 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2359 free(p);
2360
2361 int i = OSContainer::active_processor_count();
2362 st->print("active_processor_count: ");
2363 if (i > 0) {
2364 st->print("%d\n", i);
2365 } else {
2366 st->print("not supported\n");
2367 }
2368
2369 i = OSContainer::cpu_quota();
2370 st->print("cpu_quota: ");
2371 if (i > 0) {
2372 st->print("%d\n", i);
2373 } else {
2374 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2375 }
2376
2377 i = OSContainer::cpu_period();
2378 st->print("cpu_period: ");
2379 if (i > 0) {
2380 st->print("%d\n", i);
2381 } else {
2382 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2383 }
2384
2385 i = OSContainer::cpu_shares();
2386 st->print("cpu_shares: ");
2387 if (i > 0) {
2388 st->print("%d\n", i);
2389 } else {
2390 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2391 }
2392
2393 jlong j = OSContainer::memory_limit_in_bytes();
2394 st->print("memory_limit_in_bytes: ");
2395 if (j > 0) {
2396 st->print(JLONG_FORMAT "\n", j);
2397 } else {
2398 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2399 }
2400
2401 j = OSContainer::memory_and_swap_limit_in_bytes();
2402 st->print("memory_and_swap_limit_in_bytes: ");
2403 if (j > 0) {
2404 st->print(JLONG_FORMAT "\n", j);
2405 } else {
2406 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2407 }
2408
2409 j = OSContainer::memory_soft_limit_in_bytes();
2410 st->print("memory_soft_limit_in_bytes: ");
2411 if (j > 0) {
2412 st->print(JLONG_FORMAT "\n", j);
2413 } else {
2414 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2415 }
2416
2417 j = OSContainer::OSContainer::memory_usage_in_bytes();
2418 st->print("memory_usage_in_bytes: ");
2419 if (j > 0) {
2420 st->print(JLONG_FORMAT "\n", j);
2421 } else {
2422 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2423 }
2424
2425 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2426 st->print("memory_max_usage_in_bytes: ");
2427 if (j > 0) {
2428 st->print(JLONG_FORMAT "\n", j);
2429 } else {
2430 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2431 }
2432 st->cr();
2433 }
2434
2435 void os::Linux::print_steal_info(outputStream* st) {
2436 if (has_initial_tick_info) {
2437 CPUPerfTicks pticks;
2438 bool res = os::Linux::get_tick_information(&pticks, -1);
2439
2440 if (res && pticks.has_steal_ticks) {
2441 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2442 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2443 double steal_ticks_perc = 0.0;
2444 if (total_ticks_difference != 0) {
2445 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2446 }
2447 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2448 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2449 }
2450 }
2451 }
2452
2453 void os::print_memory_info(outputStream* st) {
2454
2455 st->print("Memory:");
2456 st->print(" %dk page", os::vm_page_size()>>10);
2457
2458 // values in struct sysinfo are "unsigned long"
2459 struct sysinfo si;
2460 sysinfo(&si);
2461
2462 st->print(", physical " UINT64_FORMAT "k",
2463 os::physical_memory() >> 10);
2464 st->print("(" UINT64_FORMAT "k free)",
2465 os::available_memory() >> 10);
2466 st->print(", swap " UINT64_FORMAT "k",
2467 ((jlong)si.totalswap * si.mem_unit) >> 10);
2468 st->print("(" UINT64_FORMAT "k free)",
2469 ((jlong)si.freeswap * si.mem_unit) >> 10);
2470 st->cr();
2471 }
2472
2473 // Print the first "model name" line and the first "flags" line
2474 // that we find and nothing more. We assume "model name" comes
2475 // before "flags" so if we find a second "model name", then the
2476 // "flags" field is considered missing.
2477 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2478 #if defined(IA32) || defined(AMD64)
2479 // Other platforms have less repetitive cpuinfo files
2480 FILE *fp = fopen("/proc/cpuinfo", "r");
2481 if (fp) {
2482 while (!feof(fp)) {
2483 if (fgets(buf, buflen, fp)) {
2484 // Assume model name comes before flags
2485 bool model_name_printed = false;
2486 if (strstr(buf, "model name") != NULL) {
2487 if (!model_name_printed) {
2488 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2489 st->print_raw(buf);
2490 model_name_printed = true;
2491 } else {
2492 // model name printed but not flags? Odd, just return
2493 fclose(fp);
2494 return true;
2495 }
2496 }
2497 // print the flags line too
2498 if (strstr(buf, "flags") != NULL) {
2499 st->print_raw(buf);
2500 fclose(fp);
2501 return true;
2502 }
2503 }
2504 }
2505 fclose(fp);
2506 }
2507 #endif // x86 platforms
2508 return false;
2509 }
2510
2511 // additional information about CPU e.g. available frequency ranges
2512 static void print_sys_devices_cpu_info(outputStream* st, char* buf, size_t buflen) {
2513 _print_ascii_file_h("Online cpus:", "/sys/devices/system/cpu/online", st);
2514 _print_ascii_file_h("Offline cpus:", "/sys/devices/system/cpu/offline", st);
2515
2516 if (ExtensiveErrorReports) {
2517 // cache related info (cpu 0, should be similar for other CPUs)
2518 for (unsigned int i=0; i < 10; i++) { // handle max. 10 cache entries
2519 char hbuf_level[60];
2520 char hbuf_type[60];
2521 char hbuf_size[60];
2522 char hbuf_coherency_line_size[80];
2523 snprintf(hbuf_level, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/level", i);
2524 snprintf(hbuf_type, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/type", i);
2525 snprintf(hbuf_size, 60, "/sys/devices/system/cpu/cpu0/cache/index%u/size", i);
2526 snprintf(hbuf_coherency_line_size, 80, "/sys/devices/system/cpu/cpu0/cache/index%u/coherency_line_size", i);
2527 if (file_exists(hbuf_level)) {
2528 _print_ascii_file_h("cache level:", hbuf_level, st);
2529 _print_ascii_file_h("cache type:", hbuf_type, st);
2530 _print_ascii_file_h("cache size:", hbuf_size, st);
2531 _print_ascii_file_h("cache coherency line size:", hbuf_coherency_line_size, st);
2532 }
2533 }
2534 }
2535
2536 // we miss the cpufreq entries on Power and s390x
2537 #if defined(IA32) || defined(AMD64)
2538 _print_ascii_file_h("BIOS frequency limitation:", "/sys/devices/system/cpu/cpu0/cpufreq/bios_limit", st);
2539 _print_ascii_file_h("Frequency switch latency (ns):", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency", st);
2540 _print_ascii_file_h("Available cpu frequencies:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", st);
2541 // min and max should be in the Available range but still print them (not all info might be available for all kernels)
2542 if (ExtensiveErrorReports) {
2543 _print_ascii_file_h("Maximum cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", st);
2544 _print_ascii_file_h("Minimum cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq", st);
2545 _print_ascii_file_h("Current cpu frequency:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq", st);
2546 }
2547 // governors are power schemes, see https://wiki.archlinux.org/index.php/CPU_frequency_scaling
2548 if (ExtensiveErrorReports) {
2549 _print_ascii_file_h("Available governors:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors", st);
2550 }
2551 _print_ascii_file_h("Current governor:", "/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor", st);
2552 // Core performance boost, see https://www.kernel.org/doc/Documentation/cpu-freq/boost.txt
2553 // Raise operating frequency of some cores in a multi-core package if certain conditions apply, e.g.
2554 // whole chip is not fully utilized
2555 _print_ascii_file_h("Core performance/turbo boost:", "/sys/devices/system/cpu/cpufreq/boost", st);
2556 #endif
2557 }
2558
2559 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2560 // Only print the model name if the platform provides this as a summary
2561 if (!print_model_name_and_flags(st, buf, buflen)) {
2562 st->print("\n/proc/cpuinfo:\n");
2563 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2564 st->print_cr(" <Not Available>");
2565 }
2566 }
2567 print_sys_devices_cpu_info(st, buf, buflen);
2568 }
2569
2570 #if defined(AMD64) || defined(IA32) || defined(X32)
2571 const char* search_string = "model name";
2572 #elif defined(M68K)
2573 const char* search_string = "CPU";
2574 #elif defined(PPC64)
2575 const char* search_string = "cpu";
2576 #elif defined(S390)
2577 const char* search_string = "machine =";
2578 #elif defined(SPARC)
2579 const char* search_string = "cpu";
2580 #else
2581 const char* search_string = "Processor";
2582 #endif
2583
2584 // Parses the cpuinfo file for string representing the model name.
2585 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2586 FILE* fp = fopen("/proc/cpuinfo", "r");
2587 if (fp != NULL) {
2588 while (!feof(fp)) {
2589 char buf[256];
2590 if (fgets(buf, sizeof(buf), fp)) {
2591 char* start = strstr(buf, search_string);
2592 if (start != NULL) {
2593 char *ptr = start + strlen(search_string);
2594 char *end = buf + strlen(buf);
2595 while (ptr != end) {
2596 // skip whitespace and colon for the rest of the name.
2597 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2598 break;
2599 }
2600 ptr++;
2601 }
2602 if (ptr != end) {
2603 // reasonable string, get rid of newline and keep the rest
2604 char* nl = strchr(buf, '\n');
2605 if (nl != NULL) *nl = '\0';
2606 strncpy(cpuinfo, ptr, length);
2607 fclose(fp);
2608 return;
2609 }
2610 }
2611 }
2612 }
2613 fclose(fp);
2614 }
2615 // cpuinfo not found or parsing failed, just print generic string. The entire
2616 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2617 #if defined(AARCH64)
2618 strncpy(cpuinfo, "AArch64", length);
2619 #elif defined(AMD64)
2620 strncpy(cpuinfo, "x86_64", length);
2621 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2622 strncpy(cpuinfo, "ARM", length);
2623 #elif defined(IA32)
2624 strncpy(cpuinfo, "x86_32", length);
2625 #elif defined(IA64)
2626 strncpy(cpuinfo, "IA64", length);
2627 #elif defined(PPC)
2628 strncpy(cpuinfo, "PPC64", length);
2629 #elif defined(S390)
2630 strncpy(cpuinfo, "S390", length);
2631 #elif defined(SPARC)
2632 strncpy(cpuinfo, "sparcv9", length);
2633 #elif defined(ZERO_LIBARCH)
2634 strncpy(cpuinfo, ZERO_LIBARCH, length);
2635 #else
2636 strncpy(cpuinfo, "unknown", length);
2637 #endif
2638 }
2639
2640 static void print_signal_handler(outputStream* st, int sig,
2641 char* buf, size_t buflen);
2642
2643 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2644 st->print_cr("Signal Handlers:");
2645 print_signal_handler(st, SIGSEGV, buf, buflen);
2646 print_signal_handler(st, SIGBUS , buf, buflen);
2647 print_signal_handler(st, SIGFPE , buf, buflen);
2648 print_signal_handler(st, SIGPIPE, buf, buflen);
2649 print_signal_handler(st, SIGXFSZ, buf, buflen);
2650 print_signal_handler(st, SIGILL , buf, buflen);
2651 print_signal_handler(st, SR_signum, buf, buflen);
2652 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2653 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2654 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2655 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2656 #if defined(PPC64)
2657 print_signal_handler(st, SIGTRAP, buf, buflen);
2658 #endif
2659 }
2660
2661 static char saved_jvm_path[MAXPATHLEN] = {0};
2662
2663 // Find the full path to the current module, libjvm.so
2664 void os::jvm_path(char *buf, jint buflen) {
2665 // Error checking.
2666 if (buflen < MAXPATHLEN) {
2667 assert(false, "must use a large-enough buffer");
2668 buf[0] = '\0';
2669 return;
2670 }
2671 // Lazy resolve the path to current module.
2672 if (saved_jvm_path[0] != 0) {
2673 strcpy(buf, saved_jvm_path);
2674 return;
2675 }
2676
2677 char dli_fname[MAXPATHLEN];
2678 bool ret = dll_address_to_library_name(
2679 CAST_FROM_FN_PTR(address, os::jvm_path),
2680 dli_fname, sizeof(dli_fname), NULL);
2681 assert(ret, "cannot locate libjvm");
2682 char *rp = NULL;
2683 if (ret && dli_fname[0] != '\0') {
2684 rp = os::Posix::realpath(dli_fname, buf, buflen);
2685 }
2686 if (rp == NULL) {
2687 return;
2688 }
2689
2690 if (Arguments::sun_java_launcher_is_altjvm()) {
2691 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2692 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2693 // If "/jre/lib/" appears at the right place in the string, then
2694 // assume we are installed in a JDK and we're done. Otherwise, check
2695 // for a JAVA_HOME environment variable and fix up the path so it
2696 // looks like libjvm.so is installed there (append a fake suffix
2697 // hotspot/libjvm.so).
2698 const char *p = buf + strlen(buf) - 1;
2699 for (int count = 0; p > buf && count < 5; ++count) {
2700 for (--p; p > buf && *p != '/'; --p)
2701 /* empty */ ;
2702 }
2703
2704 if (strncmp(p, "/jre/lib/", 9) != 0) {
2705 // Look for JAVA_HOME in the environment.
2706 char* java_home_var = ::getenv("JAVA_HOME");
2707 if (java_home_var != NULL && java_home_var[0] != 0) {
2708 char* jrelib_p;
2709 int len;
2710
2711 // Check the current module name "libjvm.so".
2712 p = strrchr(buf, '/');
2713 if (p == NULL) {
2714 return;
2715 }
2716 assert(strstr(p, "/libjvm") == p, "invalid library name");
2717
2718 rp = os::Posix::realpath(java_home_var, buf, buflen);
2719 if (rp == NULL) {
2720 return;
2721 }
2722
2723 // determine if this is a legacy image or modules image
2724 // modules image doesn't have "jre" subdirectory
2725 len = strlen(buf);
2726 assert(len < buflen, "Ran out of buffer room");
2727 jrelib_p = buf + len;
2728 snprintf(jrelib_p, buflen-len, "/jre/lib");
2729 if (0 != access(buf, F_OK)) {
2730 snprintf(jrelib_p, buflen-len, "/lib");
2731 }
2732
2733 if (0 == access(buf, F_OK)) {
2734 // Use current module name "libjvm.so"
2735 len = strlen(buf);
2736 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2737 } else {
2738 // Go back to path of .so
2739 rp = os::Posix::realpath(dli_fname, buf, buflen);
2740 if (rp == NULL) {
2741 return;
2742 }
2743 }
2744 }
2745 }
2746 }
2747
2748 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2749 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2750 }
2751
2752 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2753 // no prefix required, not even "_"
2754 }
2755
2756 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2757 // no suffix required
2758 }
2759
2760 ////////////////////////////////////////////////////////////////////////////////
2761 // sun.misc.Signal support
2762
2763 static void UserHandler(int sig, void *siginfo, void *context) {
2764 // Ctrl-C is pressed during error reporting, likely because the error
2765 // handler fails to abort. Let VM die immediately.
2766 if (sig == SIGINT && VMError::is_error_reported()) {
2767 os::die();
2768 }
2769
2770 os::signal_notify(sig);
2771 }
2772
2773 void* os::user_handler() {
2774 return CAST_FROM_FN_PTR(void*, UserHandler);
2775 }
2776
2777 extern "C" {
2778 typedef void (*sa_handler_t)(int);
2779 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2780 }
2781
2782 void* os::signal(int signal_number, void* handler) {
2783 struct sigaction sigAct, oldSigAct;
2784
2785 sigfillset(&(sigAct.sa_mask));
2786 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2787 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2788
2789 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2790 // -1 means registration failed
2791 return (void *)-1;
2792 }
2793
2794 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2795 }
2796
2797 void os::signal_raise(int signal_number) {
2798 ::raise(signal_number);
2799 }
2800
2801 // The following code is moved from os.cpp for making this
2802 // code platform specific, which it is by its very nature.
2803
2804 // Will be modified when max signal is changed to be dynamic
2805 int os::sigexitnum_pd() {
2806 return NSIG;
2807 }
2808
2809 // a counter for each possible signal value
2810 static volatile jint pending_signals[NSIG+1] = { 0 };
2811
2812 // Linux(POSIX) specific hand shaking semaphore.
2813 static Semaphore* sig_sem = NULL;
2814 static PosixSemaphore sr_semaphore;
2815
2816 static void jdk_misc_signal_init() {
2817 // Initialize signal structures
2818 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2819
2820 // Initialize signal semaphore
2821 sig_sem = new Semaphore();
2822 }
2823
2824 void os::signal_notify(int sig) {
2825 if (sig_sem != NULL) {
2826 Atomic::inc(&pending_signals[sig]);
2827 sig_sem->signal();
2828 } else {
2829 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2830 // initialization isn't called.
2831 assert(ReduceSignalUsage, "signal semaphore should be created");
2832 }
2833 }
2834
2835 static int check_pending_signals() {
2836 for (;;) {
2837 for (int i = 0; i < NSIG + 1; i++) {
2838 jint n = pending_signals[i];
2839 if (n > 0 && n == Atomic::cmpxchg(&pending_signals[i], n, n - 1)) {
2840 return i;
2841 }
2842 }
2843 JavaThread *thread = JavaThread::current();
2844 ThreadBlockInVM tbivm(thread);
2845
2846 bool threadIsSuspended;
2847 do {
2848 thread->set_suspend_equivalent();
2849 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2850 sig_sem->wait();
2851
2852 // were we externally suspended while we were waiting?
2853 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2854 if (threadIsSuspended) {
2855 // The semaphore has been incremented, but while we were waiting
2856 // another thread suspended us. We don't want to continue running
2857 // while suspended because that would surprise the thread that
2858 // suspended us.
2859 sig_sem->signal();
2860
2861 thread->java_suspend_self();
2862 }
2863 } while (threadIsSuspended);
2864 }
2865 }
2866
2867 int os::signal_wait() {
2868 return check_pending_signals();
2869 }
2870
2871 ////////////////////////////////////////////////////////////////////////////////
2872 // Virtual Memory
2873
2874 int os::vm_page_size() {
2875 // Seems redundant as all get out
2876 assert(os::Linux::page_size() != -1, "must call os::init");
2877 return os::Linux::page_size();
2878 }
2879
2880 // Solaris allocates memory by pages.
2881 int os::vm_allocation_granularity() {
2882 assert(os::Linux::page_size() != -1, "must call os::init");
2883 return os::Linux::page_size();
2884 }
2885
2886 // Rationale behind this function:
2887 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2888 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2889 // samples for JITted code. Here we create private executable mapping over the code cache
2890 // and then we can use standard (well, almost, as mapping can change) way to provide
2891 // info for the reporting script by storing timestamp and location of symbol
2892 void linux_wrap_code(char* base, size_t size) {
2893 static volatile jint cnt = 0;
2894
2895 if (!UseOprofile) {
2896 return;
2897 }
2898
2899 char buf[PATH_MAX+1];
2900 int num = Atomic::add(&cnt, 1);
2901
2902 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2903 os::get_temp_directory(), os::current_process_id(), num);
2904 unlink(buf);
2905
2906 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2907
2908 if (fd != -1) {
2909 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2910 if (rv != (off_t)-1) {
2911 if (::write(fd, "", 1) == 1) {
2912 mmap(base, size,
2913 PROT_READ|PROT_WRITE|PROT_EXEC,
2914 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2915 }
2916 }
2917 ::close(fd);
2918 unlink(buf);
2919 }
2920 }
2921
2922 static bool recoverable_mmap_error(int err) {
2923 // See if the error is one we can let the caller handle. This
2924 // list of errno values comes from JBS-6843484. I can't find a
2925 // Linux man page that documents this specific set of errno
2926 // values so while this list currently matches Solaris, it may
2927 // change as we gain experience with this failure mode.
2928 switch (err) {
2929 case EBADF:
2930 case EINVAL:
2931 case ENOTSUP:
2932 // let the caller deal with these errors
2933 return true;
2934
2935 default:
2936 // Any remaining errors on this OS can cause our reserved mapping
2937 // to be lost. That can cause confusion where different data
2938 // structures think they have the same memory mapped. The worst
2939 // scenario is if both the VM and a library think they have the
2940 // same memory mapped.
2941 return false;
2942 }
2943 }
2944
2945 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2946 int err) {
2947 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2948 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2949 os::strerror(err), err);
2950 }
2951
2952 static void warn_fail_commit_memory(char* addr, size_t size,
2953 size_t alignment_hint, bool exec,
2954 int err) {
2955 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2956 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2957 alignment_hint, exec, os::strerror(err), err);
2958 }
2959
2960 // NOTE: Linux kernel does not really reserve the pages for us.
2961 // All it does is to check if there are enough free pages
2962 // left at the time of mmap(). This could be a potential
2963 // problem.
2964 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2965 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2966 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2967 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2968 if (res != (uintptr_t) MAP_FAILED) {
2969 if (UseNUMAInterleaving) {
2970 numa_make_global(addr, size);
2971 }
2972 return 0;
2973 }
2974
2975 int err = errno; // save errno from mmap() call above
2976
2977 if (!recoverable_mmap_error(err)) {
2978 warn_fail_commit_memory(addr, size, exec, err);
2979 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2980 }
2981
2982 return err;
2983 }
2984
2985 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2986 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2987 }
2988
2989 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2990 const char* mesg) {
2991 assert(mesg != NULL, "mesg must be specified");
2992 int err = os::Linux::commit_memory_impl(addr, size, exec);
2993 if (err != 0) {
2994 // the caller wants all commit errors to exit with the specified mesg:
2995 warn_fail_commit_memory(addr, size, exec, err);
2996 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2997 }
2998 }
2999
3000 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
3001 #ifndef MAP_HUGETLB
3002 #define MAP_HUGETLB 0x40000
3003 #endif
3004
3005 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
3006 #ifndef MADV_HUGEPAGE
3007 #define MADV_HUGEPAGE 14
3008 #endif
3009
3010 int os::Linux::commit_memory_impl(char* addr, size_t size,
3011 size_t alignment_hint, bool exec) {
3012 int err = os::Linux::commit_memory_impl(addr, size, exec);
3013 if (err == 0) {
3014 realign_memory(addr, size, alignment_hint);
3015 }
3016 return err;
3017 }
3018
3019 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
3020 bool exec) {
3021 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
3022 }
3023
3024 void os::pd_commit_memory_or_exit(char* addr, size_t size,
3025 size_t alignment_hint, bool exec,
3026 const char* mesg) {
3027 assert(mesg != NULL, "mesg must be specified");
3028 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
3029 if (err != 0) {
3030 // the caller wants all commit errors to exit with the specified mesg:
3031 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
3032 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
3033 }
3034 }
3035
3036 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
3037 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
3038 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
3039 // be supported or the memory may already be backed by huge pages.
3040 ::madvise(addr, bytes, MADV_HUGEPAGE);
3041 }
3042 }
3043
3044 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
3045 // This method works by doing an mmap over an existing mmaping and effectively discarding
3046 // the existing pages. However it won't work for SHM-based large pages that cannot be
3047 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
3048 // small pages on top of the SHM segment. This method always works for small pages, so we
3049 // allow that in any case.
3050 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
3051 commit_memory(addr, bytes, alignment_hint, !ExecMem);
3052 }
3053 }
3054
3055 void os::numa_make_global(char *addr, size_t bytes) {
3056 Linux::numa_interleave_memory(addr, bytes);
3057 }
3058
3059 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
3060 // bind policy to MPOL_PREFERRED for the current thread.
3061 #define USE_MPOL_PREFERRED 0
3062
3063 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
3064 // To make NUMA and large pages more robust when both enabled, we need to ease
3065 // the requirements on where the memory should be allocated. MPOL_BIND is the
3066 // default policy and it will force memory to be allocated on the specified
3067 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
3068 // the specified node, but will not force it. Using this policy will prevent
3069 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
3070 // free large pages.
3071 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
3072 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
3073 }
3074
3075 bool os::numa_topology_changed() { return false; }
3076
3077 size_t os::numa_get_groups_num() {
3078 // Return just the number of nodes in which it's possible to allocate memory
3079 // (in numa terminology, configured nodes).
3080 return Linux::numa_num_configured_nodes();
3081 }
3082
3083 int os::numa_get_group_id() {
3084 int cpu_id = Linux::sched_getcpu();
3085 if (cpu_id != -1) {
3086 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
3087 if (lgrp_id != -1) {
3088 return lgrp_id;
3089 }
3090 }
3091 return 0;
3092 }
3093
3094 int os::numa_get_group_id_for_address(const void* address) {
3095 void** pages = const_cast<void**>(&address);
3096 int id = -1;
3097
3098 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
3099 return -1;
3100 }
3101 if (id < 0) {
3102 return -1;
3103 }
3104 return id;
3105 }
3106
3107 int os::Linux::get_existing_num_nodes() {
3108 int node;
3109 int highest_node_number = Linux::numa_max_node();
3110 int num_nodes = 0;
3111
3112 // Get the total number of nodes in the system including nodes without memory.
3113 for (node = 0; node <= highest_node_number; node++) {
3114 if (is_node_in_existing_nodes(node)) {
3115 num_nodes++;
3116 }
3117 }
3118 return num_nodes;
3119 }
3120
3121 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
3122 int highest_node_number = Linux::numa_max_node();
3123 size_t i = 0;
3124
3125 // Map all node ids in which it is possible to allocate memory. Also nodes are
3126 // not always consecutively available, i.e. available from 0 to the highest
3127 // node number. If the nodes have been bound explicitly using numactl membind,
3128 // then allocate memory from those nodes only.
3129 for (int node = 0; node <= highest_node_number; node++) {
3130 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
3131 ids[i++] = node;
3132 }
3133 }
3134 return i;
3135 }
3136
3137 bool os::get_page_info(char *start, page_info* info) {
3138 return false;
3139 }
3140
3141 char *os::scan_pages(char *start, char* end, page_info* page_expected,
3142 page_info* page_found) {
3143 return end;
3144 }
3145
3146
3147 int os::Linux::sched_getcpu_syscall(void) {
3148 unsigned int cpu = 0;
3149 int retval = -1;
3150
3151 #if defined(IA32)
3152 #ifndef SYS_getcpu
3153 #define SYS_getcpu 318
3154 #endif
3155 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
3156 #elif defined(AMD64)
3157 // Unfortunately we have to bring all these macros here from vsyscall.h
3158 // to be able to compile on old linuxes.
3159 #define __NR_vgetcpu 2
3160 #define VSYSCALL_START (-10UL << 20)
3161 #define VSYSCALL_SIZE 1024
3162 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
3163 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
3164 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
3165 retval = vgetcpu(&cpu, NULL, NULL);
3166 #endif
3167
3168 return (retval == -1) ? retval : cpu;
3169 }
3170
3171 void os::Linux::sched_getcpu_init() {
3172 // sched_getcpu() should be in libc.
3173 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3174 dlsym(RTLD_DEFAULT, "sched_getcpu")));
3175
3176 // If it's not, try a direct syscall.
3177 if (sched_getcpu() == -1) {
3178 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3179 (void*)&sched_getcpu_syscall));
3180 }
3181
3182 if (sched_getcpu() == -1) {
3183 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
3184 }
3185 }
3186
3187 // Something to do with the numa-aware allocator needs these symbols
3188 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3189 extern "C" JNIEXPORT void numa_error(char *where) { }
3190
3191 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3192 // load symbol from base version instead.
3193 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3194 void *f = dlvsym(handle, name, "libnuma_1.1");
3195 if (f == NULL) {
3196 f = dlsym(handle, name);
3197 }
3198 return f;
3199 }
3200
3201 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3202 // Return NULL if the symbol is not defined in this particular version.
3203 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3204 return dlvsym(handle, name, "libnuma_1.2");
3205 }
3206
3207 bool os::Linux::libnuma_init() {
3208 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3209 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3210 if (handle != NULL) {
3211 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3212 libnuma_dlsym(handle, "numa_node_to_cpus")));
3213 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3214 libnuma_dlsym(handle, "numa_max_node")));
3215 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3216 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3217 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3218 libnuma_dlsym(handle, "numa_available")));
3219 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3220 libnuma_dlsym(handle, "numa_tonode_memory")));
3221 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3222 libnuma_dlsym(handle, "numa_interleave_memory")));
3223 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3224 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3225 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3226 libnuma_dlsym(handle, "numa_set_bind_policy")));
3227 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3228 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3229 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3230 libnuma_dlsym(handle, "numa_distance")));
3231 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3232 libnuma_v2_dlsym(handle, "numa_get_membind")));
3233 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3234 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3235 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3236 libnuma_dlsym(handle, "numa_move_pages")));
3237 set_numa_set_preferred(CAST_TO_FN_PTR(numa_set_preferred_func_t,
3238 libnuma_dlsym(handle, "numa_set_preferred")));
3239
3240 if (numa_available() != -1) {
3241 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3242 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3243 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3244 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3245 set_numa_membind_bitmask(_numa_get_membind());
3246 // Create an index -> node mapping, since nodes are not always consecutive
3247 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3248 rebuild_nindex_to_node_map();
3249 // Create a cpu -> node mapping
3250 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3251 rebuild_cpu_to_node_map();
3252 return true;
3253 }
3254 }
3255 }
3256 return false;
3257 }
3258
3259 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3260 // Creating guard page is very expensive. Java thread has HotSpot
3261 // guard pages, only enable glibc guard page for non-Java threads.
3262 // (Remember: compiler thread is a Java thread, too!)
3263 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3264 }
3265
3266 void os::Linux::rebuild_nindex_to_node_map() {
3267 int highest_node_number = Linux::numa_max_node();
3268
3269 nindex_to_node()->clear();
3270 for (int node = 0; node <= highest_node_number; node++) {
3271 if (Linux::is_node_in_existing_nodes(node)) {
3272 nindex_to_node()->append(node);
3273 }
3274 }
3275 }
3276
3277 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3278 // The table is later used in get_node_by_cpu().
3279 void os::Linux::rebuild_cpu_to_node_map() {
3280 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3281 // in libnuma (possible values are starting from 16,
3282 // and continuing up with every other power of 2, but less
3283 // than the maximum number of CPUs supported by kernel), and
3284 // is a subject to change (in libnuma version 2 the requirements
3285 // are more reasonable) we'll just hardcode the number they use
3286 // in the library.
3287 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3288
3289 size_t cpu_num = processor_count();
3290 size_t cpu_map_size = NCPUS / BitsPerCLong;
3291 size_t cpu_map_valid_size =
3292 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3293
3294 cpu_to_node()->clear();
3295 cpu_to_node()->at_grow(cpu_num - 1);
3296
3297 size_t node_num = get_existing_num_nodes();
3298
3299 int distance = 0;
3300 int closest_distance = INT_MAX;
3301 int closest_node = 0;
3302 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3303 for (size_t i = 0; i < node_num; i++) {
3304 // Check if node is configured (not a memory-less node). If it is not, find
3305 // the closest configured node. Check also if node is bound, i.e. it's allowed
3306 // to allocate memory from the node. If it's not allowed, map cpus in that node
3307 // to the closest node from which memory allocation is allowed.
3308 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3309 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3310 closest_distance = INT_MAX;
3311 // Check distance from all remaining nodes in the system. Ignore distance
3312 // from itself, from another non-configured node, and from another non-bound
3313 // node.
3314 for (size_t m = 0; m < node_num; m++) {
3315 if (m != i &&
3316 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3317 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3318 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3319 // If a closest node is found, update. There is always at least one
3320 // configured and bound node in the system so there is always at least
3321 // one node close.
3322 if (distance != 0 && distance < closest_distance) {
3323 closest_distance = distance;
3324 closest_node = nindex_to_node()->at(m);
3325 }
3326 }
3327 }
3328 } else {
3329 // Current node is already a configured node.
3330 closest_node = nindex_to_node()->at(i);
3331 }
3332
3333 // Get cpus from the original node and map them to the closest node. If node
3334 // is a configured node (not a memory-less node), then original node and
3335 // closest node are the same.
3336 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3337 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3338 if (cpu_map[j] != 0) {
3339 for (size_t k = 0; k < BitsPerCLong; k++) {
3340 if (cpu_map[j] & (1UL << k)) {
3341 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3342 }
3343 }
3344 }
3345 }
3346 }
3347 }
3348 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3349 }
3350
3351 int os::Linux::get_node_by_cpu(int cpu_id) {
3352 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3353 return cpu_to_node()->at(cpu_id);
3354 }
3355 return -1;
3356 }
3357
3358 GrowableArray<int>* os::Linux::_cpu_to_node;
3359 GrowableArray<int>* os::Linux::_nindex_to_node;
3360 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3361 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3362 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3363 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3364 os::Linux::numa_available_func_t os::Linux::_numa_available;
3365 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3366 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3367 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3368 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3369 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3370 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3371 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3372 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3373 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3374 os::Linux::numa_set_preferred_func_t os::Linux::_numa_set_preferred;
3375 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3376 unsigned long* os::Linux::_numa_all_nodes;
3377 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3378 struct bitmask* os::Linux::_numa_nodes_ptr;
3379 struct bitmask* os::Linux::_numa_interleave_bitmask;
3380 struct bitmask* os::Linux::_numa_membind_bitmask;
3381
3382 bool os::pd_uncommit_memory(char* addr, size_t size) {
3383 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3384 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3385 return res != (uintptr_t) MAP_FAILED;
3386 }
3387
3388 static address get_stack_commited_bottom(address bottom, size_t size) {
3389 address nbot = bottom;
3390 address ntop = bottom + size;
3391
3392 size_t page_sz = os::vm_page_size();
3393 unsigned pages = size / page_sz;
3394
3395 unsigned char vec[1];
3396 unsigned imin = 1, imax = pages + 1, imid;
3397 int mincore_return_value = 0;
3398
3399 assert(imin <= imax, "Unexpected page size");
3400
3401 while (imin < imax) {
3402 imid = (imax + imin) / 2;
3403 nbot = ntop - (imid * page_sz);
3404
3405 // Use a trick with mincore to check whether the page is mapped or not.
3406 // mincore sets vec to 1 if page resides in memory and to 0 if page
3407 // is swapped output but if page we are asking for is unmapped
3408 // it returns -1,ENOMEM
3409 mincore_return_value = mincore(nbot, page_sz, vec);
3410
3411 if (mincore_return_value == -1) {
3412 // Page is not mapped go up
3413 // to find first mapped page
3414 if (errno != EAGAIN) {
3415 assert(errno == ENOMEM, "Unexpected mincore errno");
3416 imax = imid;
3417 }
3418 } else {
3419 // Page is mapped go down
3420 // to find first not mapped page
3421 imin = imid + 1;
3422 }
3423 }
3424
3425 nbot = nbot + page_sz;
3426
3427 // Adjust stack bottom one page up if last checked page is not mapped
3428 if (mincore_return_value == -1) {
3429 nbot = nbot + page_sz;
3430 }
3431
3432 return nbot;
3433 }
3434
3435 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3436 int mincore_return_value;
3437 const size_t stripe = 1024; // query this many pages each time
3438 unsigned char vec[stripe + 1];
3439 // set a guard
3440 vec[stripe] = 'X';
3441
3442 const size_t page_sz = os::vm_page_size();
3443 size_t pages = size / page_sz;
3444
3445 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3446 assert(is_aligned(size, page_sz), "Size must be page aligned");
3447
3448 committed_start = NULL;
3449
3450 int loops = (pages + stripe - 1) / stripe;
3451 int committed_pages = 0;
3452 address loop_base = start;
3453 bool found_range = false;
3454
3455 for (int index = 0; index < loops && !found_range; index ++) {
3456 assert(pages > 0, "Nothing to do");
3457 int pages_to_query = (pages >= stripe) ? stripe : pages;
3458 pages -= pages_to_query;
3459
3460 // Get stable read
3461 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3462
3463 // During shutdown, some memory goes away without properly notifying NMT,
3464 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3465 // Bailout and return as not committed for now.
3466 if (mincore_return_value == -1 && errno == ENOMEM) {
3467 return false;
3468 }
3469
3470 assert(vec[stripe] == 'X', "overflow guard");
3471 assert(mincore_return_value == 0, "Range must be valid");
3472 // Process this stripe
3473 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3474 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3475 // End of current contiguous region
3476 if (committed_start != NULL) {
3477 found_range = true;
3478 break;
3479 }
3480 } else { // committed
3481 // Start of region
3482 if (committed_start == NULL) {
3483 committed_start = loop_base + page_sz * vecIdx;
3484 }
3485 committed_pages ++;
3486 }
3487 }
3488
3489 loop_base += pages_to_query * page_sz;
3490 }
3491
3492 if (committed_start != NULL) {
3493 assert(committed_pages > 0, "Must have committed region");
3494 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3495 assert(committed_start >= start && committed_start < start + size, "Out of range");
3496 committed_size = page_sz * committed_pages;
3497 return true;
3498 } else {
3499 assert(committed_pages == 0, "Should not have committed region");
3500 return false;
3501 }
3502 }
3503
3504
3505 // Linux uses a growable mapping for the stack, and if the mapping for
3506 // the stack guard pages is not removed when we detach a thread the
3507 // stack cannot grow beyond the pages where the stack guard was
3508 // mapped. If at some point later in the process the stack expands to
3509 // that point, the Linux kernel cannot expand the stack any further
3510 // because the guard pages are in the way, and a segfault occurs.
3511 //
3512 // However, it's essential not to split the stack region by unmapping
3513 // a region (leaving a hole) that's already part of the stack mapping,
3514 // so if the stack mapping has already grown beyond the guard pages at
3515 // the time we create them, we have to truncate the stack mapping.
3516 // So, we need to know the extent of the stack mapping when
3517 // create_stack_guard_pages() is called.
3518
3519 // We only need this for stacks that are growable: at the time of
3520 // writing thread stacks don't use growable mappings (i.e. those
3521 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3522 // only applies to the main thread.
3523
3524 // If the (growable) stack mapping already extends beyond the point
3525 // where we're going to put our guard pages, truncate the mapping at
3526 // that point by munmap()ping it. This ensures that when we later
3527 // munmap() the guard pages we don't leave a hole in the stack
3528 // mapping. This only affects the main/primordial thread
3529
3530 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3531 if (os::is_primordial_thread()) {
3532 // As we manually grow stack up to bottom inside create_attached_thread(),
3533 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3534 // we don't need to do anything special.
3535 // Check it first, before calling heavy function.
3536 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3537 unsigned char vec[1];
3538
3539 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3540 // Fallback to slow path on all errors, including EAGAIN
3541 stack_extent = (uintptr_t) get_stack_commited_bottom(
3542 os::Linux::initial_thread_stack_bottom(),
3543 (size_t)addr - stack_extent);
3544 }
3545
3546 if (stack_extent < (uintptr_t)addr) {
3547 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3548 }
3549 }
3550
3551 return os::commit_memory(addr, size, !ExecMem);
3552 }
3553
3554 // If this is a growable mapping, remove the guard pages entirely by
3555 // munmap()ping them. If not, just call uncommit_memory(). This only
3556 // affects the main/primordial thread, but guard against future OS changes.
3557 // It's safe to always unmap guard pages for primordial thread because we
3558 // always place it right after end of the mapped region.
3559
3560 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3561 uintptr_t stack_extent, stack_base;
3562
3563 if (os::is_primordial_thread()) {
3564 return ::munmap(addr, size) == 0;
3565 }
3566
3567 return os::uncommit_memory(addr, size);
3568 }
3569
3570 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3571 // at 'requested_addr'. If there are existing memory mappings at the same
3572 // location, however, they will be overwritten. If 'fixed' is false,
3573 // 'requested_addr' is only treated as a hint, the return value may or
3574 // may not start from the requested address. Unlike Linux mmap(), this
3575 // function returns NULL to indicate failure.
3576 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3577 char * addr;
3578 int flags;
3579
3580 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3581 if (fixed) {
3582 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3583 flags |= MAP_FIXED;
3584 }
3585
3586 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3587 // touch an uncommitted page. Otherwise, the read/write might
3588 // succeed if we have enough swap space to back the physical page.
3589 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3590 flags, -1, 0);
3591
3592 return addr == MAP_FAILED ? NULL : addr;
3593 }
3594
3595 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3596 // (req_addr != NULL) or with a given alignment.
3597 // - bytes shall be a multiple of alignment.
3598 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3599 // - alignment sets the alignment at which memory shall be allocated.
3600 // It must be a multiple of allocation granularity.
3601 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3602 // req_addr or NULL.
3603 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3604
3605 size_t extra_size = bytes;
3606 if (req_addr == NULL && alignment > 0) {
3607 extra_size += alignment;
3608 }
3609
3610 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3611 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3612 -1, 0);
3613 if (start == MAP_FAILED) {
3614 start = NULL;
3615 } else {
3616 if (req_addr != NULL) {
3617 if (start != req_addr) {
3618 ::munmap(start, extra_size);
3619 start = NULL;
3620 }
3621 } else {
3622 char* const start_aligned = align_up(start, alignment);
3623 char* const end_aligned = start_aligned + bytes;
3624 char* const end = start + extra_size;
3625 if (start_aligned > start) {
3626 ::munmap(start, start_aligned - start);
3627 }
3628 if (end_aligned < end) {
3629 ::munmap(end_aligned, end - end_aligned);
3630 }
3631 start = start_aligned;
3632 }
3633 }
3634 return start;
3635 }
3636
3637 static int anon_munmap(char * addr, size_t size) {
3638 return ::munmap(addr, size) == 0;
3639 }
3640
3641 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3642 size_t alignment_hint) {
3643 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3644 }
3645
3646 bool os::pd_release_memory(char* addr, size_t size) {
3647 return anon_munmap(addr, size);
3648 }
3649
3650 static bool linux_mprotect(char* addr, size_t size, int prot) {
3651 // Linux wants the mprotect address argument to be page aligned.
3652 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3653
3654 // According to SUSv3, mprotect() should only be used with mappings
3655 // established by mmap(), and mmap() always maps whole pages. Unaligned
3656 // 'addr' likely indicates problem in the VM (e.g. trying to change
3657 // protection of malloc'ed or statically allocated memory). Check the
3658 // caller if you hit this assert.
3659 assert(addr == bottom, "sanity check");
3660
3661 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3662 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3663 return ::mprotect(bottom, size, prot) == 0;
3664 }
3665
3666 // Set protections specified
3667 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3668 bool is_committed) {
3669 unsigned int p = 0;
3670 switch (prot) {
3671 case MEM_PROT_NONE: p = PROT_NONE; break;
3672 case MEM_PROT_READ: p = PROT_READ; break;
3673 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3674 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3675 default:
3676 ShouldNotReachHere();
3677 }
3678 // is_committed is unused.
3679 return linux_mprotect(addr, bytes, p);
3680 }
3681
3682 bool os::guard_memory(char* addr, size_t size) {
3683 return linux_mprotect(addr, size, PROT_NONE);
3684 }
3685
3686 bool os::unguard_memory(char* addr, size_t size) {
3687 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3688 }
3689
3690 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3691 size_t page_size) {
3692 bool result = false;
3693 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3694 MAP_ANONYMOUS|MAP_PRIVATE,
3695 -1, 0);
3696 if (p != MAP_FAILED) {
3697 void *aligned_p = align_up(p, page_size);
3698
3699 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3700
3701 munmap(p, page_size * 2);
3702 }
3703
3704 if (warn && !result) {
3705 warning("TransparentHugePages is not supported by the operating system.");
3706 }
3707
3708 return result;
3709 }
3710
3711 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3712 bool result = false;
3713 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3714 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3715 -1, 0);
3716
3717 if (p != MAP_FAILED) {
3718 // We don't know if this really is a huge page or not.
3719 FILE *fp = fopen("/proc/self/maps", "r");
3720 if (fp) {
3721 while (!feof(fp)) {
3722 char chars[257];
3723 long x = 0;
3724 if (fgets(chars, sizeof(chars), fp)) {
3725 if (sscanf(chars, "%lx-%*x", &x) == 1
3726 && x == (long)p) {
3727 if (strstr (chars, "hugepage")) {
3728 result = true;
3729 break;
3730 }
3731 }
3732 }
3733 }
3734 fclose(fp);
3735 }
3736 munmap(p, page_size);
3737 }
3738
3739 if (warn && !result) {
3740 warning("HugeTLBFS is not supported by the operating system.");
3741 }
3742
3743 return result;
3744 }
3745
3746 // From the coredump_filter documentation:
3747 //
3748 // - (bit 0) anonymous private memory
3749 // - (bit 1) anonymous shared memory
3750 // - (bit 2) file-backed private memory
3751 // - (bit 3) file-backed shared memory
3752 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3753 // effective only if the bit 2 is cleared)
3754 // - (bit 5) hugetlb private memory
3755 // - (bit 6) hugetlb shared memory
3756 // - (bit 7) dax private memory
3757 // - (bit 8) dax shared memory
3758 //
3759 static void set_coredump_filter(CoredumpFilterBit bit) {
3760 FILE *f;
3761 long cdm;
3762
3763 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3764 return;
3765 }
3766
3767 if (fscanf(f, "%lx", &cdm) != 1) {
3768 fclose(f);
3769 return;
3770 }
3771
3772 long saved_cdm = cdm;
3773 rewind(f);
3774 cdm |= bit;
3775
3776 if (cdm != saved_cdm) {
3777 fprintf(f, "%#lx", cdm);
3778 }
3779
3780 fclose(f);
3781 }
3782
3783 // Large page support
3784
3785 static size_t _large_page_size = 0;
3786
3787 size_t os::Linux::find_large_page_size() {
3788 size_t large_page_size = 0;
3789
3790 // large_page_size on Linux is used to round up heap size. x86 uses either
3791 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3792 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3793 // page as large as 256M.
3794 //
3795 // Here we try to figure out page size by parsing /proc/meminfo and looking
3796 // for a line with the following format:
3797 // Hugepagesize: 2048 kB
3798 //
3799 // If we can't determine the value (e.g. /proc is not mounted, or the text
3800 // format has been changed), we'll use the largest page size supported by
3801 // the processor.
3802
3803 #ifndef ZERO
3804 large_page_size =
3805 AARCH64_ONLY(2 * M)
3806 AMD64_ONLY(2 * M)
3807 ARM32_ONLY(2 * M)
3808 IA32_ONLY(4 * M)
3809 IA64_ONLY(256 * M)
3810 PPC_ONLY(4 * M)
3811 S390_ONLY(1 * M)
3812 SPARC_ONLY(4 * M);
3813 #endif // ZERO
3814
3815 FILE *fp = fopen("/proc/meminfo", "r");
3816 if (fp) {
3817 while (!feof(fp)) {
3818 int x = 0;
3819 char buf[16];
3820 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3821 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3822 large_page_size = x * K;
3823 break;
3824 }
3825 } else {
3826 // skip to next line
3827 for (;;) {
3828 int ch = fgetc(fp);
3829 if (ch == EOF || ch == (int)'\n') break;
3830 }
3831 }
3832 }
3833 fclose(fp);
3834 }
3835
3836 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3837 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3838 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3839 proper_unit_for_byte_size(large_page_size));
3840 }
3841
3842 return large_page_size;
3843 }
3844
3845 size_t os::Linux::setup_large_page_size() {
3846 _large_page_size = Linux::find_large_page_size();
3847 const size_t default_page_size = (size_t)Linux::page_size();
3848 if (_large_page_size > default_page_size) {
3849 _page_sizes[0] = _large_page_size;
3850 _page_sizes[1] = default_page_size;
3851 _page_sizes[2] = 0;
3852 }
3853
3854 return _large_page_size;
3855 }
3856
3857 bool os::Linux::setup_large_page_type(size_t page_size) {
3858 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3859 FLAG_IS_DEFAULT(UseSHM) &&
3860 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3861
3862 // The type of large pages has not been specified by the user.
3863
3864 // Try UseHugeTLBFS and then UseSHM.
3865 UseHugeTLBFS = UseSHM = true;
3866
3867 // Don't try UseTransparentHugePages since there are known
3868 // performance issues with it turned on. This might change in the future.
3869 UseTransparentHugePages = false;
3870 }
3871
3872 if (UseTransparentHugePages) {
3873 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3874 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3875 UseHugeTLBFS = false;
3876 UseSHM = false;
3877 return true;
3878 }
3879 UseTransparentHugePages = false;
3880 }
3881
3882 if (UseHugeTLBFS) {
3883 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3884 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3885 UseSHM = false;
3886 return true;
3887 }
3888 UseHugeTLBFS = false;
3889 }
3890
3891 return UseSHM;
3892 }
3893
3894 void os::large_page_init() {
3895 if (!UseLargePages &&
3896 !UseTransparentHugePages &&
3897 !UseHugeTLBFS &&
3898 !UseSHM) {
3899 // Not using large pages.
3900 return;
3901 }
3902
3903 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3904 // The user explicitly turned off large pages.
3905 // Ignore the rest of the large pages flags.
3906 UseTransparentHugePages = false;
3907 UseHugeTLBFS = false;
3908 UseSHM = false;
3909 return;
3910 }
3911
3912 size_t large_page_size = Linux::setup_large_page_size();
3913 UseLargePages = Linux::setup_large_page_type(large_page_size);
3914
3915 set_coredump_filter(LARGEPAGES_BIT);
3916 }
3917
3918 #ifndef SHM_HUGETLB
3919 #define SHM_HUGETLB 04000
3920 #endif
3921
3922 #define shm_warning_format(format, ...) \
3923 do { \
3924 if (UseLargePages && \
3925 (!FLAG_IS_DEFAULT(UseLargePages) || \
3926 !FLAG_IS_DEFAULT(UseSHM) || \
3927 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3928 warning(format, __VA_ARGS__); \
3929 } \
3930 } while (0)
3931
3932 #define shm_warning(str) shm_warning_format("%s", str)
3933
3934 #define shm_warning_with_errno(str) \
3935 do { \
3936 int err = errno; \
3937 shm_warning_format(str " (error = %d)", err); \
3938 } while (0)
3939
3940 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3941 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3942
3943 if (!is_aligned(alignment, SHMLBA)) {
3944 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3945 return NULL;
3946 }
3947
3948 // To ensure that we get 'alignment' aligned memory from shmat,
3949 // we pre-reserve aligned virtual memory and then attach to that.
3950
3951 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3952 if (pre_reserved_addr == NULL) {
3953 // Couldn't pre-reserve aligned memory.
3954 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3955 return NULL;
3956 }
3957
3958 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3959 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3960
3961 if ((intptr_t)addr == -1) {
3962 int err = errno;
3963 shm_warning_with_errno("Failed to attach shared memory.");
3964
3965 assert(err != EACCES, "Unexpected error");
3966 assert(err != EIDRM, "Unexpected error");
3967 assert(err != EINVAL, "Unexpected error");
3968
3969 // Since we don't know if the kernel unmapped the pre-reserved memory area
3970 // we can't unmap it, since that would potentially unmap memory that was
3971 // mapped from other threads.
3972 return NULL;
3973 }
3974
3975 return addr;
3976 }
3977
3978 static char* shmat_at_address(int shmid, char* req_addr) {
3979 if (!is_aligned(req_addr, SHMLBA)) {
3980 assert(false, "Requested address needs to be SHMLBA aligned");
3981 return NULL;
3982 }
3983
3984 char* addr = (char*)shmat(shmid, req_addr, 0);
3985
3986 if ((intptr_t)addr == -1) {
3987 shm_warning_with_errno("Failed to attach shared memory.");
3988 return NULL;
3989 }
3990
3991 return addr;
3992 }
3993
3994 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3995 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3996 if (req_addr != NULL) {
3997 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3998 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3999 return shmat_at_address(shmid, req_addr);
4000 }
4001
4002 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
4003 // return large page size aligned memory addresses when req_addr == NULL.
4004 // However, if the alignment is larger than the large page size, we have
4005 // to manually ensure that the memory returned is 'alignment' aligned.
4006 if (alignment > os::large_page_size()) {
4007 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
4008 return shmat_with_alignment(shmid, bytes, alignment);
4009 } else {
4010 return shmat_at_address(shmid, NULL);
4011 }
4012 }
4013
4014 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
4015 char* req_addr, bool exec) {
4016 // "exec" is passed in but not used. Creating the shared image for
4017 // the code cache doesn't have an SHM_X executable permission to check.
4018 assert(UseLargePages && UseSHM, "only for SHM large pages");
4019 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4020 assert(is_aligned(req_addr, alignment), "Unaligned address");
4021
4022 if (!is_aligned(bytes, os::large_page_size())) {
4023 return NULL; // Fallback to small pages.
4024 }
4025
4026 // Create a large shared memory region to attach to based on size.
4027 // Currently, size is the total size of the heap.
4028 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
4029 if (shmid == -1) {
4030 // Possible reasons for shmget failure:
4031 // 1. shmmax is too small for Java heap.
4032 // > check shmmax value: cat /proc/sys/kernel/shmmax
4033 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
4034 // 2. not enough large page memory.
4035 // > check available large pages: cat /proc/meminfo
4036 // > increase amount of large pages:
4037 // echo new_value > /proc/sys/vm/nr_hugepages
4038 // Note 1: different Linux may use different name for this property,
4039 // e.g. on Redhat AS-3 it is "hugetlb_pool".
4040 // Note 2: it's possible there's enough physical memory available but
4041 // they are so fragmented after a long run that they can't
4042 // coalesce into large pages. Try to reserve large pages when
4043 // the system is still "fresh".
4044 shm_warning_with_errno("Failed to reserve shared memory.");
4045 return NULL;
4046 }
4047
4048 // Attach to the region.
4049 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
4050
4051 // Remove shmid. If shmat() is successful, the actual shared memory segment
4052 // will be deleted when it's detached by shmdt() or when the process
4053 // terminates. If shmat() is not successful this will remove the shared
4054 // segment immediately.
4055 shmctl(shmid, IPC_RMID, NULL);
4056
4057 return addr;
4058 }
4059
4060 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
4061 int error) {
4062 assert(error == ENOMEM, "Only expect to fail if no memory is available");
4063
4064 bool warn_on_failure = UseLargePages &&
4065 (!FLAG_IS_DEFAULT(UseLargePages) ||
4066 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
4067 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
4068
4069 if (warn_on_failure) {
4070 char msg[128];
4071 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
4072 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
4073 warning("%s", msg);
4074 }
4075 }
4076
4077 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
4078 char* req_addr,
4079 bool exec) {
4080 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4081 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
4082 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
4083
4084 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4085 char* addr = (char*)::mmap(req_addr, bytes, prot,
4086 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
4087 -1, 0);
4088
4089 if (addr == MAP_FAILED) {
4090 warn_on_large_pages_failure(req_addr, bytes, errno);
4091 return NULL;
4092 }
4093
4094 assert(is_aligned(addr, os::large_page_size()), "Must be");
4095
4096 return addr;
4097 }
4098
4099 // Reserve memory using mmap(MAP_HUGETLB).
4100 // - bytes shall be a multiple of alignment.
4101 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
4102 // - alignment sets the alignment at which memory shall be allocated.
4103 // It must be a multiple of allocation granularity.
4104 // Returns address of memory or NULL. If req_addr was not NULL, will only return
4105 // req_addr or NULL.
4106 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
4107 size_t alignment,
4108 char* req_addr,
4109 bool exec) {
4110 size_t large_page_size = os::large_page_size();
4111 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
4112
4113 assert(is_aligned(req_addr, alignment), "Must be");
4114 assert(is_aligned(bytes, alignment), "Must be");
4115
4116 // First reserve - but not commit - the address range in small pages.
4117 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
4118
4119 if (start == NULL) {
4120 return NULL;
4121 }
4122
4123 assert(is_aligned(start, alignment), "Must be");
4124
4125 char* end = start + bytes;
4126
4127 // Find the regions of the allocated chunk that can be promoted to large pages.
4128 char* lp_start = align_up(start, large_page_size);
4129 char* lp_end = align_down(end, large_page_size);
4130
4131 size_t lp_bytes = lp_end - lp_start;
4132
4133 assert(is_aligned(lp_bytes, large_page_size), "Must be");
4134
4135 if (lp_bytes == 0) {
4136 // The mapped region doesn't even span the start and the end of a large page.
4137 // Fall back to allocate a non-special area.
4138 ::munmap(start, end - start);
4139 return NULL;
4140 }
4141
4142 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4143
4144 void* result;
4145
4146 // Commit small-paged leading area.
4147 if (start != lp_start) {
4148 result = ::mmap(start, lp_start - start, prot,
4149 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4150 -1, 0);
4151 if (result == MAP_FAILED) {
4152 ::munmap(lp_start, end - lp_start);
4153 return NULL;
4154 }
4155 }
4156
4157 // Commit large-paged area.
4158 result = ::mmap(lp_start, lp_bytes, prot,
4159 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
4160 -1, 0);
4161 if (result == MAP_FAILED) {
4162 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
4163 // If the mmap above fails, the large pages region will be unmapped and we
4164 // have regions before and after with small pages. Release these regions.
4165 //
4166 // | mapped | unmapped | mapped |
4167 // ^ ^ ^ ^
4168 // start lp_start lp_end end
4169 //
4170 ::munmap(start, lp_start - start);
4171 ::munmap(lp_end, end - lp_end);
4172 return NULL;
4173 }
4174
4175 // Commit small-paged trailing area.
4176 if (lp_end != end) {
4177 result = ::mmap(lp_end, end - lp_end, prot,
4178 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4179 -1, 0);
4180 if (result == MAP_FAILED) {
4181 ::munmap(start, lp_end - start);
4182 return NULL;
4183 }
4184 }
4185
4186 return start;
4187 }
4188
4189 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4190 size_t alignment,
4191 char* req_addr,
4192 bool exec) {
4193 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4194 assert(is_aligned(req_addr, alignment), "Must be");
4195 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4196 assert(is_power_of_2(os::large_page_size()), "Must be");
4197 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
4198
4199 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
4200 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
4201 } else {
4202 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
4203 }
4204 }
4205
4206 char* os::pd_reserve_memory_special(size_t bytes, size_t alignment,
4207 char* req_addr, bool exec) {
4208 assert(UseLargePages, "only for large pages");
4209
4210 char* addr;
4211 if (UseSHM) {
4212 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4213 } else {
4214 assert(UseHugeTLBFS, "must be");
4215 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4216 }
4217
4218 if (addr != NULL) {
4219 if (UseNUMAInterleaving) {
4220 numa_make_global(addr, bytes);
4221 }
4222 }
4223
4224 return addr;
4225 }
4226
4227 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4228 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4229 return shmdt(base) == 0;
4230 }
4231
4232 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4233 return pd_release_memory(base, bytes);
4234 }
4235
4236 bool os::pd_release_memory_special(char* base, size_t bytes) {
4237 assert(UseLargePages, "only for large pages");
4238 bool res;
4239
4240 if (UseSHM) {
4241 res = os::Linux::release_memory_special_shm(base, bytes);
4242 } else {
4243 assert(UseHugeTLBFS, "must be");
4244 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4245 }
4246 return res;
4247 }
4248
4249 size_t os::large_page_size() {
4250 return _large_page_size;
4251 }
4252
4253 // With SysV SHM the entire memory region must be allocated as shared
4254 // memory.
4255 // HugeTLBFS allows application to commit large page memory on demand.
4256 // However, when committing memory with HugeTLBFS fails, the region
4257 // that was supposed to be committed will lose the old reservation
4258 // and allow other threads to steal that memory region. Because of this
4259 // behavior we can't commit HugeTLBFS memory.
4260 bool os::can_commit_large_page_memory() {
4261 return UseTransparentHugePages;
4262 }
4263
4264 bool os::can_execute_large_page_memory() {
4265 return UseTransparentHugePages || UseHugeTLBFS;
4266 }
4267
4268 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4269 assert(file_desc >= 0, "file_desc is not valid");
4270 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4271 if (result != NULL) {
4272 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4273 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4274 }
4275 }
4276 return result;
4277 }
4278
4279 // Reserve memory at an arbitrary address, only if that area is
4280 // available (and not reserved for something else).
4281
4282 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4283 // Assert only that the size is a multiple of the page size, since
4284 // that's all that mmap requires, and since that's all we really know
4285 // about at this low abstraction level. If we need higher alignment,
4286 // we can either pass an alignment to this method or verify alignment
4287 // in one of the methods further up the call chain. See bug 5044738.
4288 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4289
4290 // Repeatedly allocate blocks until the block is allocated at the
4291 // right spot.
4292
4293 // Linux mmap allows caller to pass an address as hint; give it a try first,
4294 // if kernel honors the hint then we can return immediately.
4295 char * addr = anon_mmap(requested_addr, bytes, false);
4296 if (addr == requested_addr) {
4297 return requested_addr;
4298 }
4299
4300 if (addr != NULL) {
4301 // mmap() is successful but it fails to reserve at the requested address
4302 anon_munmap(addr, bytes);
4303 }
4304
4305 return NULL;
4306 }
4307
4308 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4309 void os::infinite_sleep() {
4310 while (true) { // sleep forever ...
4311 ::sleep(100); // ... 100 seconds at a time
4312 }
4313 }
4314
4315 // Used to convert frequent JVM_Yield() to nops
4316 bool os::dont_yield() {
4317 return DontYieldALot;
4318 }
4319
4320 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4321 // actually give up the CPU. Since skip buddy (v2.6.28):
4322 //
4323 // * Sets the yielding task as skip buddy for current CPU's run queue.
4324 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4325 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4326 //
4327 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4328 // getting re-scheduled immediately.
4329 //
4330 void os::naked_yield() {
4331 sched_yield();
4332 }
4333
4334 ////////////////////////////////////////////////////////////////////////////////
4335 // thread priority support
4336
4337 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4338 // only supports dynamic priority, static priority must be zero. For real-time
4339 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4340 // However, for large multi-threaded applications, SCHED_RR is not only slower
4341 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4342 // of 5 runs - Sep 2005).
4343 //
4344 // The following code actually changes the niceness of kernel-thread/LWP. It
4345 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4346 // not the entire user process, and user level threads are 1:1 mapped to kernel
4347 // threads. It has always been the case, but could change in the future. For
4348 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4349 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4350 // (e.g., root privilege or CAP_SYS_NICE capability).
4351
4352 int os::java_to_os_priority[CriticalPriority + 1] = {
4353 19, // 0 Entry should never be used
4354
4355 4, // 1 MinPriority
4356 3, // 2
4357 2, // 3
4358
4359 1, // 4
4360 0, // 5 NormPriority
4361 -1, // 6
4362
4363 -2, // 7
4364 -3, // 8
4365 -4, // 9 NearMaxPriority
4366
4367 -5, // 10 MaxPriority
4368
4369 -5 // 11 CriticalPriority
4370 };
4371
4372 static int prio_init() {
4373 if (ThreadPriorityPolicy == 1) {
4374 if (geteuid() != 0) {
4375 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy) && !FLAG_IS_JIMAGE_RESOURCE(ThreadPriorityPolicy)) {
4376 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4377 "e.g., being the root user. If the necessary permission is not " \
4378 "possessed, changes to priority will be silently ignored.");
4379 }
4380 }
4381 }
4382 if (UseCriticalJavaThreadPriority) {
4383 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4384 }
4385 return 0;
4386 }
4387
4388 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4389 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4390
4391 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4392 return (ret == 0) ? OS_OK : OS_ERR;
4393 }
4394
4395 OSReturn os::get_native_priority(const Thread* const thread,
4396 int *priority_ptr) {
4397 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4398 *priority_ptr = java_to_os_priority[NormPriority];
4399 return OS_OK;
4400 }
4401
4402 errno = 0;
4403 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4404 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4405 }
4406
4407 ////////////////////////////////////////////////////////////////////////////////
4408 // suspend/resume support
4409
4410 // The low-level signal-based suspend/resume support is a remnant from the
4411 // old VM-suspension that used to be for java-suspension, safepoints etc,
4412 // within hotspot. Currently used by JFR's OSThreadSampler
4413 //
4414 // The remaining code is greatly simplified from the more general suspension
4415 // code that used to be used.
4416 //
4417 // The protocol is quite simple:
4418 // - suspend:
4419 // - sends a signal to the target thread
4420 // - polls the suspend state of the osthread using a yield loop
4421 // - target thread signal handler (SR_handler) sets suspend state
4422 // and blocks in sigsuspend until continued
4423 // - resume:
4424 // - sets target osthread state to continue
4425 // - sends signal to end the sigsuspend loop in the SR_handler
4426 //
4427 // Note that the SR_lock plays no role in this suspend/resume protocol,
4428 // but is checked for NULL in SR_handler as a thread termination indicator.
4429 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4430 //
4431 // Note that resume_clear_context() and suspend_save_context() are needed
4432 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4433 // which in part is used by:
4434 // - Forte Analyzer: AsyncGetCallTrace()
4435 // - StackBanging: get_frame_at_stack_banging_point()
4436
4437 static void resume_clear_context(OSThread *osthread) {
4438 osthread->set_ucontext(NULL);
4439 osthread->set_siginfo(NULL);
4440 }
4441
4442 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4443 ucontext_t* context) {
4444 osthread->set_ucontext(context);
4445 osthread->set_siginfo(siginfo);
4446 }
4447
4448 // Handler function invoked when a thread's execution is suspended or
4449 // resumed. We have to be careful that only async-safe functions are
4450 // called here (Note: most pthread functions are not async safe and
4451 // should be avoided.)
4452 //
4453 // Note: sigwait() is a more natural fit than sigsuspend() from an
4454 // interface point of view, but sigwait() prevents the signal hander
4455 // from being run. libpthread would get very confused by not having
4456 // its signal handlers run and prevents sigwait()'s use with the
4457 // mutex granting granting signal.
4458 //
4459 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4460 //
4461 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4462 // Save and restore errno to avoid confusing native code with EINTR
4463 // after sigsuspend.
4464 int old_errno = errno;
4465
4466 Thread* thread = Thread::current_or_null_safe();
4467 assert(thread != NULL, "Missing current thread in SR_handler");
4468
4469 // On some systems we have seen signal delivery get "stuck" until the signal
4470 // mask is changed as part of thread termination. Check that the current thread
4471 // has not already terminated (via SR_lock()) - else the following assertion
4472 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4473 // destructor has completed.
4474
4475 if (thread->SR_lock() == NULL) {
4476 return;
4477 }
4478
4479 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4480
4481 OSThread* osthread = thread->osthread();
4482
4483 os::SuspendResume::State current = osthread->sr.state();
4484 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4485 suspend_save_context(osthread, siginfo, context);
4486
4487 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4488 os::SuspendResume::State state = osthread->sr.suspended();
4489 if (state == os::SuspendResume::SR_SUSPENDED) {
4490 sigset_t suspend_set; // signals for sigsuspend()
4491 sigemptyset(&suspend_set);
4492 // get current set of blocked signals and unblock resume signal
4493 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4494 sigdelset(&suspend_set, SR_signum);
4495
4496 sr_semaphore.signal();
4497 // wait here until we are resumed
4498 while (1) {
4499 sigsuspend(&suspend_set);
4500
4501 os::SuspendResume::State result = osthread->sr.running();
4502 if (result == os::SuspendResume::SR_RUNNING) {
4503 sr_semaphore.signal();
4504 break;
4505 }
4506 }
4507
4508 } else if (state == os::SuspendResume::SR_RUNNING) {
4509 // request was cancelled, continue
4510 } else {
4511 ShouldNotReachHere();
4512 }
4513
4514 resume_clear_context(osthread);
4515 } else if (current == os::SuspendResume::SR_RUNNING) {
4516 // request was cancelled, continue
4517 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4518 // ignore
4519 } else {
4520 // ignore
4521 }
4522
4523 errno = old_errno;
4524 }
4525
4526 static int SR_initialize() {
4527 struct sigaction act;
4528 char *s;
4529
4530 // Get signal number to use for suspend/resume
4531 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4532 int sig = ::strtol(s, 0, 10);
4533 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4534 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4535 SR_signum = sig;
4536 } else {
4537 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4538 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4539 }
4540 }
4541
4542 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4543 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4544
4545 sigemptyset(&SR_sigset);
4546 sigaddset(&SR_sigset, SR_signum);
4547
4548 // Set up signal handler for suspend/resume
4549 act.sa_flags = SA_RESTART|SA_SIGINFO;
4550 act.sa_handler = (void (*)(int)) SR_handler;
4551
4552 // SR_signum is blocked by default.
4553 // 4528190 - We also need to block pthread restart signal (32 on all
4554 // supported Linux platforms). Note that LinuxThreads need to block
4555 // this signal for all threads to work properly. So we don't have
4556 // to use hard-coded signal number when setting up the mask.
4557 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4558
4559 if (sigaction(SR_signum, &act, 0) == -1) {
4560 return -1;
4561 }
4562
4563 // Save signal flag
4564 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4565 return 0;
4566 }
4567
4568 static int sr_notify(OSThread* osthread) {
4569 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4570 assert_status(status == 0, status, "pthread_kill");
4571 return status;
4572 }
4573
4574 // "Randomly" selected value for how long we want to spin
4575 // before bailing out on suspending a thread, also how often
4576 // we send a signal to a thread we want to resume
4577 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4578 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4579
4580 // returns true on success and false on error - really an error is fatal
4581 // but this seems the normal response to library errors
4582 static bool do_suspend(OSThread* osthread) {
4583 assert(osthread->sr.is_running(), "thread should be running");
4584 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4585
4586 // mark as suspended and send signal
4587 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4588 // failed to switch, state wasn't running?
4589 ShouldNotReachHere();
4590 return false;
4591 }
4592
4593 if (sr_notify(osthread) != 0) {
4594 ShouldNotReachHere();
4595 }
4596
4597 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4598 while (true) {
4599 if (sr_semaphore.timedwait(2)) {
4600 break;
4601 } else {
4602 // timeout
4603 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4604 if (cancelled == os::SuspendResume::SR_RUNNING) {
4605 return false;
4606 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4607 // make sure that we consume the signal on the semaphore as well
4608 sr_semaphore.wait();
4609 break;
4610 } else {
4611 ShouldNotReachHere();
4612 return false;
4613 }
4614 }
4615 }
4616
4617 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4618 return true;
4619 }
4620
4621 static void do_resume(OSThread* osthread) {
4622 assert(osthread->sr.is_suspended(), "thread should be suspended");
4623 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4624
4625 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4626 // failed to switch to WAKEUP_REQUEST
4627 ShouldNotReachHere();
4628 return;
4629 }
4630
4631 while (true) {
4632 if (sr_notify(osthread) == 0) {
4633 if (sr_semaphore.timedwait(2)) {
4634 if (osthread->sr.is_running()) {
4635 return;
4636 }
4637 }
4638 } else {
4639 ShouldNotReachHere();
4640 }
4641 }
4642
4643 guarantee(osthread->sr.is_running(), "Must be running!");
4644 }
4645
4646 ///////////////////////////////////////////////////////////////////////////////////
4647 // signal handling (except suspend/resume)
4648
4649 // This routine may be used by user applications as a "hook" to catch signals.
4650 // The user-defined signal handler must pass unrecognized signals to this
4651 // routine, and if it returns true (non-zero), then the signal handler must
4652 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4653 // routine will never retun false (zero), but instead will execute a VM panic
4654 // routine kill the process.
4655 //
4656 // If this routine returns false, it is OK to call it again. This allows
4657 // the user-defined signal handler to perform checks either before or after
4658 // the VM performs its own checks. Naturally, the user code would be making
4659 // a serious error if it tried to handle an exception (such as a null check
4660 // or breakpoint) that the VM was generating for its own correct operation.
4661 //
4662 // This routine may recognize any of the following kinds of signals:
4663 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4664 // It should be consulted by handlers for any of those signals.
4665 //
4666 // The caller of this routine must pass in the three arguments supplied
4667 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4668 // field of the structure passed to sigaction(). This routine assumes that
4669 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4670 //
4671 // Note that the VM will print warnings if it detects conflicting signal
4672 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4673 //
4674 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4675 siginfo_t* siginfo,
4676 void* ucontext,
4677 int abort_if_unrecognized);
4678
4679 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4680 assert(info != NULL && uc != NULL, "it must be old kernel");
4681 int orig_errno = errno; // Preserve errno value over signal handler.
4682 JVM_handle_linux_signal(sig, info, uc, true);
4683 errno = orig_errno;
4684 }
4685
4686
4687 // This boolean allows users to forward their own non-matching signals
4688 // to JVM_handle_linux_signal, harmlessly.
4689 bool os::Linux::signal_handlers_are_installed = false;
4690
4691 // For signal-chaining
4692 bool os::Linux::libjsig_is_loaded = false;
4693 typedef struct sigaction *(*get_signal_t)(int);
4694 get_signal_t os::Linux::get_signal_action = NULL;
4695
4696 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4697 struct sigaction *actp = NULL;
4698
4699 if (libjsig_is_loaded) {
4700 // Retrieve the old signal handler from libjsig
4701 actp = (*get_signal_action)(sig);
4702 }
4703 if (actp == NULL) {
4704 // Retrieve the preinstalled signal handler from jvm
4705 actp = os::Posix::get_preinstalled_handler(sig);
4706 }
4707
4708 return actp;
4709 }
4710
4711 static bool call_chained_handler(struct sigaction *actp, int sig,
4712 siginfo_t *siginfo, void *context) {
4713 // Call the old signal handler
4714 if (actp->sa_handler == SIG_DFL) {
4715 // It's more reasonable to let jvm treat it as an unexpected exception
4716 // instead of taking the default action.
4717 return false;
4718 } else if (actp->sa_handler != SIG_IGN) {
4719 if ((actp->sa_flags & SA_NODEFER) == 0) {
4720 // automaticlly block the signal
4721 sigaddset(&(actp->sa_mask), sig);
4722 }
4723
4724 sa_handler_t hand = NULL;
4725 sa_sigaction_t sa = NULL;
4726 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4727 // retrieve the chained handler
4728 if (siginfo_flag_set) {
4729 sa = actp->sa_sigaction;
4730 } else {
4731 hand = actp->sa_handler;
4732 }
4733
4734 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4735 actp->sa_handler = SIG_DFL;
4736 }
4737
4738 // try to honor the signal mask
4739 sigset_t oset;
4740 sigemptyset(&oset);
4741 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4742
4743 // call into the chained handler
4744 if (siginfo_flag_set) {
4745 (*sa)(sig, siginfo, context);
4746 } else {
4747 (*hand)(sig);
4748 }
4749
4750 // restore the signal mask
4751 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4752 }
4753 // Tell jvm's signal handler the signal is taken care of.
4754 return true;
4755 }
4756
4757 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4758 bool chained = false;
4759 // signal-chaining
4760 if (UseSignalChaining) {
4761 struct sigaction *actp = get_chained_signal_action(sig);
4762 if (actp != NULL) {
4763 chained = call_chained_handler(actp, sig, siginfo, context);
4764 }
4765 }
4766 return chained;
4767 }
4768
4769 // for diagnostic
4770 int sigflags[NSIG];
4771
4772 int os::Linux::get_our_sigflags(int sig) {
4773 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4774 return sigflags[sig];
4775 }
4776
4777 void os::Linux::set_our_sigflags(int sig, int flags) {
4778 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4779 if (sig > 0 && sig < NSIG) {
4780 sigflags[sig] = flags;
4781 }
4782 }
4783
4784 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4785 // Check for overwrite.
4786 struct sigaction oldAct;
4787 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4788
4789 void* oldhand = oldAct.sa_sigaction
4790 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4791 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4792 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4793 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4794 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4795 if (AllowUserSignalHandlers || !set_installed) {
4796 // Do not overwrite; user takes responsibility to forward to us.
4797 return;
4798 } else if (UseSignalChaining) {
4799 // save the old handler in jvm
4800 os::Posix::save_preinstalled_handler(sig, oldAct);
4801 // libjsig also interposes the sigaction() call below and saves the
4802 // old sigaction on it own.
4803 } else {
4804 fatal("Encountered unexpected pre-existing sigaction handler "
4805 "%#lx for signal %d.", (long)oldhand, sig);
4806 }
4807 }
4808
4809 struct sigaction sigAct;
4810 sigfillset(&(sigAct.sa_mask));
4811 sigAct.sa_handler = SIG_DFL;
4812 if (!set_installed) {
4813 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4814 } else {
4815 sigAct.sa_sigaction = signalHandler;
4816 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4817 }
4818 // Save flags, which are set by ours
4819 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4820 sigflags[sig] = sigAct.sa_flags;
4821
4822 int ret = sigaction(sig, &sigAct, &oldAct);
4823 assert(ret == 0, "check");
4824
4825 void* oldhand2 = oldAct.sa_sigaction
4826 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4827 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4828 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4829 }
4830
4831 // install signal handlers for signals that HotSpot needs to
4832 // handle in order to support Java-level exception handling.
4833
4834 void os::Linux::install_signal_handlers() {
4835 if (!signal_handlers_are_installed) {
4836 signal_handlers_are_installed = true;
4837
4838 // signal-chaining
4839 typedef void (*signal_setting_t)();
4840 signal_setting_t begin_signal_setting = NULL;
4841 signal_setting_t end_signal_setting = NULL;
4842 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4843 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4844 if (begin_signal_setting != NULL) {
4845 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4846 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4847 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4848 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4849 libjsig_is_loaded = true;
4850 assert(UseSignalChaining, "should enable signal-chaining");
4851 }
4852 if (libjsig_is_loaded) {
4853 // Tell libjsig jvm is setting signal handlers
4854 (*begin_signal_setting)();
4855 }
4856
4857 set_signal_handler(SIGSEGV, true);
4858 set_signal_handler(SIGPIPE, true);
4859 set_signal_handler(SIGBUS, true);
4860 set_signal_handler(SIGILL, true);
4861 set_signal_handler(SIGFPE, true);
4862 #if defined(PPC64)
4863 set_signal_handler(SIGTRAP, true);
4864 #endif
4865 set_signal_handler(SIGXFSZ, true);
4866
4867 if (libjsig_is_loaded) {
4868 // Tell libjsig jvm finishes setting signal handlers
4869 (*end_signal_setting)();
4870 }
4871
4872 // We don't activate signal checker if libjsig is in place, we trust ourselves
4873 // and if UserSignalHandler is installed all bets are off.
4874 // Log that signal checking is off only if -verbose:jni is specified.
4875 if (CheckJNICalls) {
4876 if (libjsig_is_loaded) {
4877 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
4878 check_signals = false;
4879 }
4880 if (AllowUserSignalHandlers) {
4881 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4882 check_signals = false;
4883 }
4884 }
4885 }
4886 }
4887
4888 // This is the fastest way to get thread cpu time on Linux.
4889 // Returns cpu time (user+sys) for any thread, not only for current.
4890 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4891 // It might work on 2.6.10+ with a special kernel/glibc patch.
4892 // For reference, please, see IEEE Std 1003.1-2004:
4893 // http://www.unix.org/single_unix_specification
4894
4895 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4896 struct timespec tp;
4897 int rc = os::Posix::clock_gettime(clockid, &tp);
4898 assert(rc == 0, "clock_gettime is expected to return 0 code");
4899
4900 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4901 }
4902
4903 /////
4904 // glibc on Linux platform uses non-documented flag
4905 // to indicate, that some special sort of signal
4906 // trampoline is used.
4907 // We will never set this flag, and we should
4908 // ignore this flag in our diagnostic
4909 #ifdef SIGNIFICANT_SIGNAL_MASK
4910 #undef SIGNIFICANT_SIGNAL_MASK
4911 #endif
4912 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4913
4914 static const char* get_signal_handler_name(address handler,
4915 char* buf, int buflen) {
4916 int offset = 0;
4917 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4918 if (found) {
4919 // skip directory names
4920 const char *p1, *p2;
4921 p1 = buf;
4922 size_t len = strlen(os::file_separator());
4923 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4924 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4925 } else {
4926 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4927 }
4928 return buf;
4929 }
4930
4931 static void print_signal_handler(outputStream* st, int sig,
4932 char* buf, size_t buflen) {
4933 struct sigaction sa;
4934
4935 sigaction(sig, NULL, &sa);
4936
4937 // See comment for SIGNIFICANT_SIGNAL_MASK define
4938 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4939
4940 st->print("%s: ", os::exception_name(sig, buf, buflen));
4941
4942 address handler = (sa.sa_flags & SA_SIGINFO)
4943 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4944 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4945
4946 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4947 st->print("SIG_DFL");
4948 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4949 st->print("SIG_IGN");
4950 } else {
4951 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4952 }
4953
4954 st->print(", sa_mask[0]=");
4955 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4956
4957 address rh = VMError::get_resetted_sighandler(sig);
4958 // May be, handler was resetted by VMError?
4959 if (rh != NULL) {
4960 handler = rh;
4961 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4962 }
4963
4964 st->print(", sa_flags=");
4965 os::Posix::print_sa_flags(st, sa.sa_flags);
4966
4967 // Check: is it our handler?
4968 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4969 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4970 // It is our signal handler
4971 // check for flags, reset system-used one!
4972 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4973 st->print(
4974 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4975 os::Linux::get_our_sigflags(sig));
4976 }
4977 }
4978 st->cr();
4979 }
4980
4981
4982 #define DO_SIGNAL_CHECK(sig) \
4983 do { \
4984 if (!sigismember(&check_signal_done, sig)) { \
4985 os::Linux::check_signal_handler(sig); \
4986 } \
4987 } while (0)
4988
4989 // This method is a periodic task to check for misbehaving JNI applications
4990 // under CheckJNI, we can add any periodic checks here
4991
4992 void os::run_periodic_checks() {
4993 if (check_signals == false) return;
4994
4995 // SEGV and BUS if overridden could potentially prevent
4996 // generation of hs*.log in the event of a crash, debugging
4997 // such a case can be very challenging, so we absolutely
4998 // check the following for a good measure:
4999 DO_SIGNAL_CHECK(SIGSEGV);
5000 DO_SIGNAL_CHECK(SIGILL);
5001 DO_SIGNAL_CHECK(SIGFPE);
5002 DO_SIGNAL_CHECK(SIGBUS);
5003 DO_SIGNAL_CHECK(SIGPIPE);
5004 DO_SIGNAL_CHECK(SIGXFSZ);
5005 #if defined(PPC64)
5006 DO_SIGNAL_CHECK(SIGTRAP);
5007 #endif
5008
5009 // ReduceSignalUsage allows the user to override these handlers
5010 // see comments at the very top and jvm_md.h
5011 if (!ReduceSignalUsage) {
5012 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
5013 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
5014 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
5015 DO_SIGNAL_CHECK(BREAK_SIGNAL);
5016 }
5017
5018 DO_SIGNAL_CHECK(SR_signum);
5019 }
5020
5021 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
5022
5023 static os_sigaction_t os_sigaction = NULL;
5024
5025 void os::Linux::check_signal_handler(int sig) {
5026 char buf[O_BUFLEN];
5027 address jvmHandler = NULL;
5028
5029
5030 struct sigaction act;
5031 if (os_sigaction == NULL) {
5032 // only trust the default sigaction, in case it has been interposed
5033 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
5034 if (os_sigaction == NULL) return;
5035 }
5036
5037 os_sigaction(sig, (struct sigaction*)NULL, &act);
5038
5039
5040 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
5041
5042 address thisHandler = (act.sa_flags & SA_SIGINFO)
5043 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
5044 : CAST_FROM_FN_PTR(address, act.sa_handler);
5045
5046
5047 switch (sig) {
5048 case SIGSEGV:
5049 case SIGBUS:
5050 case SIGFPE:
5051 case SIGPIPE:
5052 case SIGILL:
5053 case SIGXFSZ:
5054 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
5055 break;
5056
5057 case SHUTDOWN1_SIGNAL:
5058 case SHUTDOWN2_SIGNAL:
5059 case SHUTDOWN3_SIGNAL:
5060 case BREAK_SIGNAL:
5061 jvmHandler = (address)user_handler();
5062 break;
5063
5064 default:
5065 if (sig == SR_signum) {
5066 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
5067 } else {
5068 return;
5069 }
5070 break;
5071 }
5072
5073 if (thisHandler != jvmHandler) {
5074 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
5075 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
5076 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
5077 // No need to check this sig any longer
5078 sigaddset(&check_signal_done, sig);
5079 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
5080 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5081 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5082 exception_name(sig, buf, O_BUFLEN));
5083 }
5084 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5085 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5086 tty->print("expected:");
5087 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
5088 tty->cr();
5089 tty->print(" found:");
5090 os::Posix::print_sa_flags(tty, act.sa_flags);
5091 tty->cr();
5092 // No need to check this sig any longer
5093 sigaddset(&check_signal_done, sig);
5094 }
5095
5096 // Dump all the signal
5097 if (sigismember(&check_signal_done, sig)) {
5098 print_signal_handlers(tty, buf, O_BUFLEN);
5099 }
5100 }
5101
5102 extern void report_error(char* file_name, int line_no, char* title,
5103 char* format, ...);
5104
5105 // this is called _before_ most of the global arguments have been parsed
5106 void os::init(void) {
5107 char dummy; // used to get a guess on initial stack address
5108
5109 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5110
5111 init_random(1234567);
5112
5113 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5114 if (Linux::page_size() == -1) {
5115 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5116 os::strerror(errno));
5117 }
5118 init_page_sizes((size_t) Linux::page_size());
5119
5120 Linux::initialize_system_info();
5121
5122 os::Linux::CPUPerfTicks pticks;
5123 bool res = os::Linux::get_tick_information(&pticks, -1);
5124
5125 if (res && pticks.has_steal_ticks) {
5126 has_initial_tick_info = true;
5127 initial_total_ticks = pticks.total;
5128 initial_steal_ticks = pticks.steal;
5129 }
5130
5131 // _main_thread points to the thread that created/loaded the JVM.
5132 Linux::_main_thread = pthread_self();
5133
5134 // retrieve entry point for pthread_setname_np
5135 Linux::_pthread_setname_np =
5136 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5137
5138 os::Posix::init();
5139
5140 initial_time_count = javaTimeNanos();
5141
5142 // Always warn if no monotonic clock available
5143 if (!os::Posix::supports_monotonic_clock()) {
5144 warning("No monotonic clock was available - timed services may " \
5145 "be adversely affected if the time-of-day clock changes");
5146 }
5147 }
5148
5149 // To install functions for atexit system call
5150 extern "C" {
5151 static void perfMemory_exit_helper() {
5152 perfMemory_exit();
5153 }
5154 }
5155
5156 void os::pd_init_container_support() {
5157 OSContainer::init();
5158 }
5159
5160 void os::Linux::numa_init() {
5161
5162 // Java can be invoked as
5163 // 1. Without numactl and heap will be allocated/configured on all nodes as
5164 // per the system policy.
5165 // 2. With numactl --interleave:
5166 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5167 // API for membind case bitmask is reset.
5168 // Interleave is only hint and Kernel can fallback to other nodes if
5169 // no memory is available on the target nodes.
5170 // 3. With numactl --membind:
5171 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5172 // interleave case returns bitmask of all nodes.
5173 // numa_all_nodes_ptr holds bitmask of all nodes.
5174 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5175 // bitmask when externally configured to run on all or fewer nodes.
5176
5177 if (!Linux::libnuma_init()) {
5178 UseNUMA = false;
5179 } else {
5180 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5181 // If there's only one node (they start from 0) or if the process
5182 // is bound explicitly to a single node using membind, disable NUMA unless
5183 // user explicilty forces NUMA optimizations on single-node/UMA systems
5184 UseNUMA = ForceNUMA;
5185 } else {
5186
5187 LogTarget(Info,os) log;
5188 LogStream ls(log);
5189
5190 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5191
5192 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5193 const char* numa_mode = "membind";
5194
5195 if (Linux::is_running_in_interleave_mode()) {
5196 bmp = Linux::_numa_interleave_bitmask;
5197 numa_mode = "interleave";
5198 }
5199
5200 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5201 " Heap will be configured using NUMA memory nodes:", numa_mode);
5202
5203 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5204 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5205 ls.print(" %d", node);
5206 }
5207 }
5208 }
5209 }
5210
5211 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5212 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5213 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5214 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5215 // and disable adaptive resizing.
5216 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5217 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5218 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5219 UseAdaptiveSizePolicy = false;
5220 UseAdaptiveNUMAChunkSizing = false;
5221 }
5222 }
5223 }
5224
5225 // this is called _after_ the global arguments have been parsed
5226 jint os::init_2(void) {
5227
5228 // This could be set after os::Posix::init() but all platforms
5229 // have to set it the same so we have to mirror Solaris.
5230 DEBUG_ONLY(os::set_mutex_init_done();)
5231
5232 os::Posix::init_2();
5233
5234 Linux::fast_thread_clock_init();
5235
5236 // initialize suspend/resume support - must do this before signal_sets_init()
5237 if (SR_initialize() != 0) {
5238 perror("SR_initialize failed");
5239 return JNI_ERR;
5240 }
5241
5242 Linux::signal_sets_init();
5243 Linux::install_signal_handlers();
5244 // Initialize data for jdk.internal.misc.Signal
5245 if (!ReduceSignalUsage) {
5246 jdk_misc_signal_init();
5247 }
5248
5249 if (AdjustStackSizeForTLS) {
5250 get_minstack_init();
5251 }
5252
5253 // Check and sets minimum stack sizes against command line options
5254 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5255 return JNI_ERR;
5256 }
5257
5258 #if defined(IA32)
5259 // Need to ensure we've determined the process's initial stack to
5260 // perform the workaround
5261 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5262 workaround_expand_exec_shield_cs_limit();
5263 #else
5264 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5265 if (!suppress_primordial_thread_resolution) {
5266 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5267 }
5268 #endif
5269
5270 Linux::libpthread_init();
5271 Linux::sched_getcpu_init();
5272 log_info(os)("HotSpot is running with %s, %s",
5273 Linux::glibc_version(), Linux::libpthread_version());
5274
5275 if (UseNUMA) {
5276 Linux::numa_init();
5277 }
5278
5279 if (MaxFDLimit) {
5280 // set the number of file descriptors to max. print out error
5281 // if getrlimit/setrlimit fails but continue regardless.
5282 struct rlimit nbr_files;
5283 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5284 if (status != 0) {
5285 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5286 } else {
5287 nbr_files.rlim_cur = nbr_files.rlim_max;
5288 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5289 if (status != 0) {
5290 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5291 }
5292 }
5293 }
5294
5295 // at-exit methods are called in the reverse order of their registration.
5296 // atexit functions are called on return from main or as a result of a
5297 // call to exit(3C). There can be only 32 of these functions registered
5298 // and atexit() does not set errno.
5299
5300 if (PerfAllowAtExitRegistration) {
5301 // only register atexit functions if PerfAllowAtExitRegistration is set.
5302 // atexit functions can be delayed until process exit time, which
5303 // can be problematic for embedded VM situations. Embedded VMs should
5304 // call DestroyJavaVM() to assure that VM resources are released.
5305
5306 // note: perfMemory_exit_helper atexit function may be removed in
5307 // the future if the appropriate cleanup code can be added to the
5308 // VM_Exit VMOperation's doit method.
5309 if (atexit(perfMemory_exit_helper) != 0) {
5310 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5311 }
5312 }
5313
5314 // initialize thread priority policy
5315 prio_init();
5316
5317 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5318 set_coredump_filter(DAX_SHARED_BIT);
5319 }
5320
5321 if (DumpPrivateMappingsInCore) {
5322 set_coredump_filter(FILE_BACKED_PVT_BIT);
5323 }
5324
5325 if (DumpSharedMappingsInCore) {
5326 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5327 }
5328
5329 return JNI_OK;
5330 }
5331
5332 // older glibc versions don't have this macro (which expands to
5333 // an optimized bit-counting function) so we have to roll our own
5334 #ifndef CPU_COUNT
5335
5336 static int _cpu_count(const cpu_set_t* cpus) {
5337 int count = 0;
5338 // only look up to the number of configured processors
5339 for (int i = 0; i < os::processor_count(); i++) {
5340 if (CPU_ISSET(i, cpus)) {
5341 count++;
5342 }
5343 }
5344 return count;
5345 }
5346
5347 #define CPU_COUNT(cpus) _cpu_count(cpus)
5348
5349 #endif // CPU_COUNT
5350
5351 // Get the current number of available processors for this process.
5352 // This value can change at any time during a process's lifetime.
5353 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5354 // If it appears there may be more than 1024 processors then we do a
5355 // dynamic check - see 6515172 for details.
5356 // If anything goes wrong we fallback to returning the number of online
5357 // processors - which can be greater than the number available to the process.
5358 int os::Linux::active_processor_count() {
5359 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5360 cpu_set_t* cpus_p = &cpus;
5361 int cpus_size = sizeof(cpu_set_t);
5362
5363 int configured_cpus = os::processor_count(); // upper bound on available cpus
5364 int cpu_count = 0;
5365
5366 // old build platforms may not support dynamic cpu sets
5367 #ifdef CPU_ALLOC
5368
5369 // To enable easy testing of the dynamic path on different platforms we
5370 // introduce a diagnostic flag: UseCpuAllocPath
5371 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5372 // kernel may use a mask bigger than cpu_set_t
5373 log_trace(os)("active_processor_count: using dynamic path %s"
5374 "- configured processors: %d",
5375 UseCpuAllocPath ? "(forced) " : "",
5376 configured_cpus);
5377 cpus_p = CPU_ALLOC(configured_cpus);
5378 if (cpus_p != NULL) {
5379 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5380 // zero it just to be safe
5381 CPU_ZERO_S(cpus_size, cpus_p);
5382 }
5383 else {
5384 // failed to allocate so fallback to online cpus
5385 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5386 log_trace(os)("active_processor_count: "
5387 "CPU_ALLOC failed (%s) - using "
5388 "online processor count: %d",
5389 os::strerror(errno), online_cpus);
5390 return online_cpus;
5391 }
5392 }
5393 else {
5394 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5395 configured_cpus);
5396 }
5397 #else // CPU_ALLOC
5398 // these stubs won't be executed
5399 #define CPU_COUNT_S(size, cpus) -1
5400 #define CPU_FREE(cpus)
5401
5402 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5403 configured_cpus);
5404 #endif // CPU_ALLOC
5405
5406 // pid 0 means the current thread - which we have to assume represents the process
5407 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5408 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5409 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5410 }
5411 else {
5412 cpu_count = CPU_COUNT(cpus_p);
5413 }
5414 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5415 }
5416 else {
5417 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5418 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5419 "which may exceed available processors", os::strerror(errno), cpu_count);
5420 }
5421
5422 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5423 CPU_FREE(cpus_p);
5424 }
5425
5426 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5427 return cpu_count;
5428 }
5429
5430 // Determine the active processor count from one of
5431 // three different sources:
5432 //
5433 // 1. User option -XX:ActiveProcessorCount
5434 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5435 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5436 //
5437 // Option 1, if specified, will always override.
5438 // If the cgroup subsystem is active and configured, we
5439 // will return the min of the cgroup and option 2 results.
5440 // This is required since tools, such as numactl, that
5441 // alter cpu affinity do not update cgroup subsystem
5442 // cpuset configuration files.
5443 int os::active_processor_count() {
5444 // User has overridden the number of active processors
5445 if (ActiveProcessorCount > 0) {
5446 log_trace(os)("active_processor_count: "
5447 "active processor count set by user : %d",
5448 ActiveProcessorCount);
5449 return ActiveProcessorCount;
5450 }
5451
5452 int active_cpus;
5453 if (OSContainer::is_containerized()) {
5454 active_cpus = OSContainer::active_processor_count();
5455 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5456 active_cpus);
5457 } else {
5458 active_cpus = os::Linux::active_processor_count();
5459 }
5460
5461 return active_cpus;
5462 }
5463
5464 uint os::processor_id() {
5465 const int id = Linux::sched_getcpu();
5466 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5467 return (uint)id;
5468 }
5469
5470 void os::set_native_thread_name(const char *name) {
5471 if (Linux::_pthread_setname_np) {
5472 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5473 snprintf(buf, sizeof(buf), "%s", name);
5474 buf[sizeof(buf) - 1] = '\0';
5475 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5476 // ERANGE should not happen; all other errors should just be ignored.
5477 assert(rc != ERANGE, "pthread_setname_np failed");
5478 }
5479 }
5480
5481 bool os::bind_to_processor(uint processor_id) {
5482 // Not yet implemented.
5483 return false;
5484 }
5485
5486 ///
5487
5488 void os::SuspendedThreadTask::internal_do_task() {
5489 if (do_suspend(_thread->osthread())) {
5490 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5491 do_task(context);
5492 do_resume(_thread->osthread());
5493 }
5494 }
5495
5496 ////////////////////////////////////////////////////////////////////////////////
5497 // debug support
5498
5499 bool os::find(address addr, outputStream* st) {
5500 Dl_info dlinfo;
5501 memset(&dlinfo, 0, sizeof(dlinfo));
5502 if (dladdr(addr, &dlinfo) != 0) {
5503 st->print(PTR_FORMAT ": ", p2i(addr));
5504 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5505 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5506 p2i(addr) - p2i(dlinfo.dli_saddr));
5507 } else if (dlinfo.dli_fbase != NULL) {
5508 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5509 } else {
5510 st->print("<absolute address>");
5511 }
5512 if (dlinfo.dli_fname != NULL) {
5513 st->print(" in %s", dlinfo.dli_fname);
5514 }
5515 if (dlinfo.dli_fbase != NULL) {
5516 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5517 }
5518 st->cr();
5519
5520 if (Verbose) {
5521 // decode some bytes around the PC
5522 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5523 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5524 address lowest = (address) dlinfo.dli_sname;
5525 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5526 if (begin < lowest) begin = lowest;
5527 Dl_info dlinfo2;
5528 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5529 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5530 end = (address) dlinfo2.dli_saddr;
5531 }
5532 Disassembler::decode(begin, end, st);
5533 }
5534 return true;
5535 }
5536 return false;
5537 }
5538
5539 ////////////////////////////////////////////////////////////////////////////////
5540 // misc
5541
5542 // This does not do anything on Linux. This is basically a hook for being
5543 // able to use structured exception handling (thread-local exception filters)
5544 // on, e.g., Win32.
5545 void
5546 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5547 JavaCallArguments* args, Thread* thread) {
5548 f(value, method, args, thread);
5549 }
5550
5551 void os::print_statistics() {
5552 }
5553
5554 bool os::message_box(const char* title, const char* message) {
5555 int i;
5556 fdStream err(defaultStream::error_fd());
5557 for (i = 0; i < 78; i++) err.print_raw("=");
5558 err.cr();
5559 err.print_raw_cr(title);
5560 for (i = 0; i < 78; i++) err.print_raw("-");
5561 err.cr();
5562 err.print_raw_cr(message);
5563 for (i = 0; i < 78; i++) err.print_raw("=");
5564 err.cr();
5565
5566 char buf[16];
5567 // Prevent process from exiting upon "read error" without consuming all CPU
5568 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5569
5570 return buf[0] == 'y' || buf[0] == 'Y';
5571 }
5572
5573 // Is a (classpath) directory empty?
5574 bool os::dir_is_empty(const char* path) {
5575 DIR *dir = NULL;
5576 struct dirent *ptr;
5577
5578 dir = opendir(path);
5579 if (dir == NULL) return true;
5580
5581 // Scan the directory
5582 bool result = true;
5583 while (result && (ptr = readdir(dir)) != NULL) {
5584 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5585 result = false;
5586 }
5587 }
5588 closedir(dir);
5589 return result;
5590 }
5591
5592 // This code originates from JDK's sysOpen and open64_w
5593 // from src/solaris/hpi/src/system_md.c
5594
5595 int os::open(const char *path, int oflag, int mode) {
5596 if (strlen(path) > MAX_PATH - 1) {
5597 errno = ENAMETOOLONG;
5598 return -1;
5599 }
5600
5601 // All file descriptors that are opened in the Java process and not
5602 // specifically destined for a subprocess should have the close-on-exec
5603 // flag set. If we don't set it, then careless 3rd party native code
5604 // might fork and exec without closing all appropriate file descriptors
5605 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5606 // turn might:
5607 //
5608 // - cause end-of-file to fail to be detected on some file
5609 // descriptors, resulting in mysterious hangs, or
5610 //
5611 // - might cause an fopen in the subprocess to fail on a system
5612 // suffering from bug 1085341.
5613 //
5614 // (Yes, the default setting of the close-on-exec flag is a Unix
5615 // design flaw)
5616 //
5617 // See:
5618 // 1085341: 32-bit stdio routines should support file descriptors >255
5619 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5620 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5621 //
5622 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5623 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5624 // because it saves a system call and removes a small window where the flag
5625 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5626 // and we fall back to using FD_CLOEXEC (see below).
5627 #ifdef O_CLOEXEC
5628 oflag |= O_CLOEXEC;
5629 #endif
5630
5631 int fd = ::open64(path, oflag, mode);
5632 if (fd == -1) return -1;
5633
5634 //If the open succeeded, the file might still be a directory
5635 {
5636 struct stat64 buf64;
5637 int ret = ::fstat64(fd, &buf64);
5638 int st_mode = buf64.st_mode;
5639
5640 if (ret != -1) {
5641 if ((st_mode & S_IFMT) == S_IFDIR) {
5642 errno = EISDIR;
5643 ::close(fd);
5644 return -1;
5645 }
5646 } else {
5647 ::close(fd);
5648 return -1;
5649 }
5650 }
5651
5652 #ifdef FD_CLOEXEC
5653 // Validate that the use of the O_CLOEXEC flag on open above worked.
5654 // With recent kernels, we will perform this check exactly once.
5655 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5656 if (!O_CLOEXEC_is_known_to_work) {
5657 int flags = ::fcntl(fd, F_GETFD);
5658 if (flags != -1) {
5659 if ((flags & FD_CLOEXEC) != 0)
5660 O_CLOEXEC_is_known_to_work = 1;
5661 else
5662 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5663 }
5664 }
5665 #endif
5666
5667 return fd;
5668 }
5669
5670
5671 // create binary file, rewriting existing file if required
5672 int os::create_binary_file(const char* path, bool rewrite_existing) {
5673 int oflags = O_WRONLY | O_CREAT;
5674 if (!rewrite_existing) {
5675 oflags |= O_EXCL;
5676 }
5677 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5678 }
5679
5680 // return current position of file pointer
5681 jlong os::current_file_offset(int fd) {
5682 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5683 }
5684
5685 // move file pointer to the specified offset
5686 jlong os::seek_to_file_offset(int fd, jlong offset) {
5687 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5688 }
5689
5690 // This code originates from JDK's sysAvailable
5691 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5692
5693 int os::available(int fd, jlong *bytes) {
5694 jlong cur, end;
5695 int mode;
5696 struct stat64 buf64;
5697
5698 if (::fstat64(fd, &buf64) >= 0) {
5699 mode = buf64.st_mode;
5700 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5701 int n;
5702 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5703 *bytes = n;
5704 return 1;
5705 }
5706 }
5707 }
5708 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5709 return 0;
5710 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5711 return 0;
5712 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5713 return 0;
5714 }
5715 *bytes = end - cur;
5716 return 1;
5717 }
5718
5719 // Map a block of memory.
5720 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5721 char *addr, size_t bytes, bool read_only,
5722 bool allow_exec) {
5723 int prot;
5724 int flags = MAP_PRIVATE;
5725
5726 if (read_only) {
5727 prot = PROT_READ;
5728 } else {
5729 prot = PROT_READ | PROT_WRITE;
5730 }
5731
5732 if (allow_exec) {
5733 prot |= PROT_EXEC;
5734 }
5735
5736 if (addr != NULL) {
5737 flags |= MAP_FIXED;
5738 }
5739
5740 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5741 fd, file_offset);
5742 if (mapped_address == MAP_FAILED) {
5743 return NULL;
5744 }
5745 return mapped_address;
5746 }
5747
5748
5749 // Remap a block of memory.
5750 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5751 char *addr, size_t bytes, bool read_only,
5752 bool allow_exec) {
5753 // same as map_memory() on this OS
5754 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5755 allow_exec);
5756 }
5757
5758
5759 // Unmap a block of memory.
5760 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5761 return munmap(addr, bytes) == 0;
5762 }
5763
5764 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5765
5766 static jlong fast_cpu_time(Thread *thread) {
5767 clockid_t clockid;
5768 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5769 &clockid);
5770 if (rc == 0) {
5771 return os::Linux::fast_thread_cpu_time(clockid);
5772 } else {
5773 // It's possible to encounter a terminated native thread that failed
5774 // to detach itself from the VM - which should result in ESRCH.
5775 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5776 return -1;
5777 }
5778 }
5779
5780 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5781 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5782 // of a thread.
5783 //
5784 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5785 // the fast estimate available on the platform.
5786
5787 jlong os::current_thread_cpu_time() {
5788 if (os::Linux::supports_fast_thread_cpu_time()) {
5789 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5790 } else {
5791 // return user + sys since the cost is the same
5792 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5793 }
5794 }
5795
5796 jlong os::thread_cpu_time(Thread* thread) {
5797 // consistent with what current_thread_cpu_time() returns
5798 if (os::Linux::supports_fast_thread_cpu_time()) {
5799 return fast_cpu_time(thread);
5800 } else {
5801 return slow_thread_cpu_time(thread, true /* user + sys */);
5802 }
5803 }
5804
5805 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5806 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5807 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5808 } else {
5809 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5810 }
5811 }
5812
5813 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5814 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5815 return fast_cpu_time(thread);
5816 } else {
5817 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5818 }
5819 }
5820
5821 // -1 on error.
5822 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5823 pid_t tid = thread->osthread()->thread_id();
5824 char *s;
5825 char stat[2048];
5826 int statlen;
5827 char proc_name[64];
5828 int count;
5829 long sys_time, user_time;
5830 char cdummy;
5831 int idummy;
5832 long ldummy;
5833 FILE *fp;
5834
5835 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5836 fp = fopen(proc_name, "r");
5837 if (fp == NULL) return -1;
5838 statlen = fread(stat, 1, 2047, fp);
5839 stat[statlen] = '\0';
5840 fclose(fp);
5841
5842 // Skip pid and the command string. Note that we could be dealing with
5843 // weird command names, e.g. user could decide to rename java launcher
5844 // to "java 1.4.2 :)", then the stat file would look like
5845 // 1234 (java 1.4.2 :)) R ... ...
5846 // We don't really need to know the command string, just find the last
5847 // occurrence of ")" and then start parsing from there. See bug 4726580.
5848 s = strrchr(stat, ')');
5849 if (s == NULL) return -1;
5850
5851 // Skip blank chars
5852 do { s++; } while (s && isspace(*s));
5853
5854 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5855 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5856 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5857 &user_time, &sys_time);
5858 if (count != 13) return -1;
5859 if (user_sys_cpu_time) {
5860 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5861 } else {
5862 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5863 }
5864 }
5865
5866 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5867 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5868 info_ptr->may_skip_backward = false; // elapsed time not wall time
5869 info_ptr->may_skip_forward = false; // elapsed time not wall time
5870 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5871 }
5872
5873 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5874 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5875 info_ptr->may_skip_backward = false; // elapsed time not wall time
5876 info_ptr->may_skip_forward = false; // elapsed time not wall time
5877 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5878 }
5879
5880 bool os::is_thread_cpu_time_supported() {
5881 return true;
5882 }
5883
5884 // System loadavg support. Returns -1 if load average cannot be obtained.
5885 // Linux doesn't yet have a (official) notion of processor sets,
5886 // so just return the system wide load average.
5887 int os::loadavg(double loadavg[], int nelem) {
5888 return ::getloadavg(loadavg, nelem);
5889 }
5890
5891 void os::pause() {
5892 char filename[MAX_PATH];
5893 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5894 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5895 } else {
5896 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5897 }
5898
5899 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5900 if (fd != -1) {
5901 struct stat buf;
5902 ::close(fd);
5903 while (::stat(filename, &buf) == 0) {
5904 (void)::poll(NULL, 0, 100);
5905 }
5906 } else {
5907 jio_fprintf(stderr,
5908 "Could not open pause file '%s', continuing immediately.\n", filename);
5909 }
5910 }
5911
5912 extern char** environ;
5913
5914 // Run the specified command in a separate process. Return its exit value,
5915 // or -1 on failure (e.g. can't fork a new process).
5916 // Unlike system(), this function can be called from signal handler. It
5917 // doesn't block SIGINT et al.
5918 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5919 const char * argv[4] = {"sh", "-c", cmd, NULL};
5920
5921 pid_t pid ;
5922
5923 if (use_vfork_if_available) {
5924 pid = vfork();
5925 } else {
5926 pid = fork();
5927 }
5928
5929 if (pid < 0) {
5930 // fork failed
5931 return -1;
5932
5933 } else if (pid == 0) {
5934 // child process
5935
5936 execve("/bin/sh", (char* const*)argv, environ);
5937
5938 // execve failed
5939 _exit(-1);
5940
5941 } else {
5942 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5943 // care about the actual exit code, for now.
5944
5945 int status;
5946
5947 // Wait for the child process to exit. This returns immediately if
5948 // the child has already exited. */
5949 while (waitpid(pid, &status, 0) < 0) {
5950 switch (errno) {
5951 case ECHILD: return 0;
5952 case EINTR: break;
5953 default: return -1;
5954 }
5955 }
5956
5957 if (WIFEXITED(status)) {
5958 // The child exited normally; get its exit code.
5959 return WEXITSTATUS(status);
5960 } else if (WIFSIGNALED(status)) {
5961 // The child exited because of a signal
5962 // The best value to return is 0x80 + signal number,
5963 // because that is what all Unix shells do, and because
5964 // it allows callers to distinguish between process exit and
5965 // process death by signal.
5966 return 0x80 + WTERMSIG(status);
5967 } else {
5968 // Unknown exit code; pass it through
5969 return status;
5970 }
5971 }
5972 }
5973
5974 // Get the default path to the core file
5975 // Returns the length of the string
5976 int os::get_core_path(char* buffer, size_t bufferSize) {
5977 /*
5978 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5979 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5980 */
5981 const int core_pattern_len = 129;
5982 char core_pattern[core_pattern_len] = {0};
5983
5984 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5985 if (core_pattern_file == -1) {
5986 return -1;
5987 }
5988
5989 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5990 ::close(core_pattern_file);
5991 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5992 return -1;
5993 }
5994 if (core_pattern[ret-1] == '\n') {
5995 core_pattern[ret-1] = '\0';
5996 } else {
5997 core_pattern[ret] = '\0';
5998 }
5999
6000 // Replace the %p in the core pattern with the process id. NOTE: we do this
6001 // only if the pattern doesn't start with "|", and we support only one %p in
6002 // the pattern.
6003 char *pid_pos = strstr(core_pattern, "%p");
6004 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
6005 int written;
6006
6007 if (core_pattern[0] == '/') {
6008 if (pid_pos != NULL) {
6009 *pid_pos = '\0';
6010 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
6011 current_process_id(), tail);
6012 } else {
6013 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6014 }
6015 } else {
6016 char cwd[PATH_MAX];
6017
6018 const char* p = get_current_directory(cwd, PATH_MAX);
6019 if (p == NULL) {
6020 return -1;
6021 }
6022
6023 if (core_pattern[0] == '|') {
6024 written = jio_snprintf(buffer, bufferSize,
6025 "\"%s\" (or dumping to %s/core.%d)",
6026 &core_pattern[1], p, current_process_id());
6027 } else if (pid_pos != NULL) {
6028 *pid_pos = '\0';
6029 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
6030 current_process_id(), tail);
6031 } else {
6032 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6033 }
6034 }
6035
6036 if (written < 0) {
6037 return -1;
6038 }
6039
6040 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6041 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6042
6043 if (core_uses_pid_file != -1) {
6044 char core_uses_pid = 0;
6045 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6046 ::close(core_uses_pid_file);
6047
6048 if (core_uses_pid == '1') {
6049 jio_snprintf(buffer + written, bufferSize - written,
6050 ".%d", current_process_id());
6051 }
6052 }
6053 }
6054
6055 return strlen(buffer);
6056 }
6057
6058 bool os::start_debugging(char *buf, int buflen) {
6059 int len = (int)strlen(buf);
6060 char *p = &buf[len];
6061
6062 jio_snprintf(p, buflen-len,
6063 "\n\n"
6064 "Do you want to debug the problem?\n\n"
6065 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6066 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6067 "Otherwise, press RETURN to abort...",
6068 os::current_process_id(), os::current_process_id(),
6069 os::current_thread_id(), os::current_thread_id());
6070
6071 bool yes = os::message_box("Unexpected Error", buf);
6072
6073 if (yes) {
6074 // yes, user asked VM to launch debugger
6075 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6076 os::current_process_id(), os::current_process_id());
6077
6078 os::fork_and_exec(buf);
6079 yes = false;
6080 }
6081 return yes;
6082 }
6083
6084
6085 // Java/Compiler thread:
6086 //
6087 // Low memory addresses
6088 // P0 +------------------------+
6089 // | |\ Java thread created by VM does not have glibc
6090 // | glibc guard page | - guard page, attached Java thread usually has
6091 // | |/ 1 glibc guard page.
6092 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6093 // | |\
6094 // | HotSpot Guard Pages | - red, yellow and reserved pages
6095 // | |/
6096 // +------------------------+ JavaThread::stack_reserved_zone_base()
6097 // | |\
6098 // | Normal Stack | -
6099 // | |/
6100 // P2 +------------------------+ Thread::stack_base()
6101 //
6102 // Non-Java thread:
6103 //
6104 // Low memory addresses
6105 // P0 +------------------------+
6106 // | |\
6107 // | glibc guard page | - usually 1 page
6108 // | |/
6109 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6110 // | |\
6111 // | Normal Stack | -
6112 // | |/
6113 // P2 +------------------------+ Thread::stack_base()
6114 //
6115 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6116 // returned from pthread_attr_getstack().
6117 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6118 // of the stack size given in pthread_attr. We work around this for
6119 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6120 //
6121 #ifndef ZERO
6122 static void current_stack_region(address * bottom, size_t * size) {
6123 if (os::is_primordial_thread()) {
6124 // primordial thread needs special handling because pthread_getattr_np()
6125 // may return bogus value.
6126 *bottom = os::Linux::initial_thread_stack_bottom();
6127 *size = os::Linux::initial_thread_stack_size();
6128 } else {
6129 pthread_attr_t attr;
6130
6131 int rslt = pthread_getattr_np(pthread_self(), &attr);
6132
6133 // JVM needs to know exact stack location, abort if it fails
6134 if (rslt != 0) {
6135 if (rslt == ENOMEM) {
6136 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6137 } else {
6138 fatal("pthread_getattr_np failed with error = %d", rslt);
6139 }
6140 }
6141
6142 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6143 fatal("Cannot locate current stack attributes!");
6144 }
6145
6146 // Work around NPTL stack guard error.
6147 size_t guard_size = 0;
6148 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6149 if (rslt != 0) {
6150 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6151 }
6152 *bottom += guard_size;
6153 *size -= guard_size;
6154
6155 pthread_attr_destroy(&attr);
6156
6157 }
6158 assert(os::current_stack_pointer() >= *bottom &&
6159 os::current_stack_pointer() < *bottom + *size, "just checking");
6160 }
6161
6162 address os::current_stack_base() {
6163 address bottom;
6164 size_t size;
6165 current_stack_region(&bottom, &size);
6166 return (bottom + size);
6167 }
6168
6169 size_t os::current_stack_size() {
6170 // This stack size includes the usable stack and HotSpot guard pages
6171 // (for the threads that have Hotspot guard pages).
6172 address bottom;
6173 size_t size;
6174 current_stack_region(&bottom, &size);
6175 return size;
6176 }
6177 #endif
6178
6179 static inline struct timespec get_mtime(const char* filename) {
6180 struct stat st;
6181 int ret = os::stat(filename, &st);
6182 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6183 return st.st_mtim;
6184 }
6185
6186 int os::compare_file_modified_times(const char* file1, const char* file2) {
6187 struct timespec filetime1 = get_mtime(file1);
6188 struct timespec filetime2 = get_mtime(file2);
6189 int diff = filetime1.tv_sec - filetime2.tv_sec;
6190 if (diff == 0) {
6191 return filetime1.tv_nsec - filetime2.tv_nsec;
6192 }
6193 return diff;
6194 }
6195
6196 bool os::supports_map_sync() {
6197 return true;
6198 }
6199
6200 /////////////// Unit tests ///////////////
6201
6202 #ifndef PRODUCT
6203
6204 class TestReserveMemorySpecial : AllStatic {
6205 public:
6206 static void small_page_write(void* addr, size_t size) {
6207 size_t page_size = os::vm_page_size();
6208
6209 char* end = (char*)addr + size;
6210 for (char* p = (char*)addr; p < end; p += page_size) {
6211 *p = 1;
6212 }
6213 }
6214
6215 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6216 if (!UseHugeTLBFS) {
6217 return;
6218 }
6219
6220 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6221
6222 if (addr != NULL) {
6223 small_page_write(addr, size);
6224
6225 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6226 }
6227 }
6228
6229 static void test_reserve_memory_special_huge_tlbfs_only() {
6230 if (!UseHugeTLBFS) {
6231 return;
6232 }
6233
6234 size_t lp = os::large_page_size();
6235
6236 for (size_t size = lp; size <= lp * 10; size += lp) {
6237 test_reserve_memory_special_huge_tlbfs_only(size);
6238 }
6239 }
6240
6241 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6242 size_t lp = os::large_page_size();
6243 size_t ag = os::vm_allocation_granularity();
6244
6245 // sizes to test
6246 const size_t sizes[] = {
6247 lp, lp + ag, lp + lp / 2, lp * 2,
6248 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6249 lp * 10, lp * 10 + lp / 2
6250 };
6251 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6252
6253 // For each size/alignment combination, we test three scenarios:
6254 // 1) with req_addr == NULL
6255 // 2) with a non-null req_addr at which we expect to successfully allocate
6256 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6257 // expect the allocation to either fail or to ignore req_addr
6258
6259 // Pre-allocate two areas; they shall be as large as the largest allocation
6260 // and aligned to the largest alignment we will be testing.
6261 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6262 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6263 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6264 -1, 0);
6265 assert(mapping1 != MAP_FAILED, "should work");
6266
6267 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6268 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6269 -1, 0);
6270 assert(mapping2 != MAP_FAILED, "should work");
6271
6272 // Unmap the first mapping, but leave the second mapping intact: the first
6273 // mapping will serve as a value for a "good" req_addr (case 2). The second
6274 // mapping, still intact, as "bad" req_addr (case 3).
6275 ::munmap(mapping1, mapping_size);
6276
6277 // Case 1
6278 for (int i = 0; i < num_sizes; i++) {
6279 const size_t size = sizes[i];
6280 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6281 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6282 if (p != NULL) {
6283 assert(is_aligned(p, alignment), "must be");
6284 small_page_write(p, size);
6285 os::Linux::release_memory_special_huge_tlbfs(p, size);
6286 }
6287 }
6288 }
6289
6290 // Case 2
6291 for (int i = 0; i < num_sizes; i++) {
6292 const size_t size = sizes[i];
6293 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6294 char* const req_addr = align_up(mapping1, alignment);
6295 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6296 if (p != NULL) {
6297 assert(p == req_addr, "must be");
6298 small_page_write(p, size);
6299 os::Linux::release_memory_special_huge_tlbfs(p, size);
6300 }
6301 }
6302 }
6303
6304 // Case 3
6305 for (int i = 0; i < num_sizes; i++) {
6306 const size_t size = sizes[i];
6307 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6308 char* const req_addr = align_up(mapping2, alignment);
6309 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6310 // as the area around req_addr contains already existing mappings, the API should always
6311 // return NULL (as per contract, it cannot return another address)
6312 assert(p == NULL, "must be");
6313 }
6314 }
6315
6316 ::munmap(mapping2, mapping_size);
6317
6318 }
6319
6320 static void test_reserve_memory_special_huge_tlbfs() {
6321 if (!UseHugeTLBFS) {
6322 return;
6323 }
6324
6325 test_reserve_memory_special_huge_tlbfs_only();
6326 test_reserve_memory_special_huge_tlbfs_mixed();
6327 }
6328
6329 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6330 if (!UseSHM) {
6331 return;
6332 }
6333
6334 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6335
6336 if (addr != NULL) {
6337 assert(is_aligned(addr, alignment), "Check");
6338 assert(is_aligned(addr, os::large_page_size()), "Check");
6339
6340 small_page_write(addr, size);
6341
6342 os::Linux::release_memory_special_shm(addr, size);
6343 }
6344 }
6345
6346 static void test_reserve_memory_special_shm() {
6347 size_t lp = os::large_page_size();
6348 size_t ag = os::vm_allocation_granularity();
6349
6350 for (size_t size = ag; size < lp * 3; size += ag) {
6351 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6352 test_reserve_memory_special_shm(size, alignment);
6353 }
6354 }
6355 }
6356
6357 static void test() {
6358 test_reserve_memory_special_huge_tlbfs();
6359 test_reserve_memory_special_shm();
6360 }
6361 };
6362
6363 void TestReserveMemorySpecial_test() {
6364 TestReserveMemorySpecial::test();
6365 }
6366
6367 #endif