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