1 /*
2 * Copyright (c) 1999, 2019, 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/orderAccess.hpp"
57 #include "runtime/osThread.hpp"
58 #include "runtime/perfMemory.hpp"
59 #include "runtime/sharedRuntime.hpp"
60 #include "runtime/statSampler.hpp"
61 #include "runtime/stubRoutines.hpp"
62 #include "runtime/thread.inline.hpp"
63 #include "runtime/threadCritical.hpp"
64 #include "runtime/threadSMR.hpp"
65 #include "runtime/timer.hpp"
66 #include "runtime/vm_version.hpp"
67 #include "semaphore_posix.hpp"
68 #include "services/attachListener.hpp"
69 #include "services/memTracker.hpp"
70 #include "services/runtimeService.hpp"
71 #include "utilities/align.hpp"
72 #include "utilities/decoder.hpp"
73 #include "utilities/defaultStream.hpp"
74 #include "utilities/events.hpp"
75 #include "utilities/elfFile.hpp"
76 #include "utilities/growableArray.hpp"
77 #include "utilities/macros.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
114 #ifndef _GNU_SOURCE
115 #define _GNU_SOURCE
116 #include <sched.h>
117 #undef _GNU_SOURCE
118 #else
119 #include <sched.h>
120 #endif
121
122 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
123 // getrusage() is prepared to handle the associated failure.
124 #ifndef RUSAGE_THREAD
125 #define RUSAGE_THREAD (1) /* only the calling thread */
126 #endif
127
128 #define MAX_PATH (2 * K)
129
130 #define MAX_SECS 100000000
131
132 // for timer info max values which include all bits
133 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
134
135 enum CoredumpFilterBit {
136 FILE_BACKED_PVT_BIT = 1 << 2,
137 FILE_BACKED_SHARED_BIT = 1 << 3,
138 LARGEPAGES_BIT = 1 << 6,
139 DAX_SHARED_BIT = 1 << 8
140 };
141
142 ////////////////////////////////////////////////////////////////////////////////
143 // global variables
144 julong os::Linux::_physical_memory = 0;
145
146 address os::Linux::_initial_thread_stack_bottom = NULL;
147 uintptr_t os::Linux::_initial_thread_stack_size = 0;
148
149 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
150 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
151 pthread_t os::Linux::_main_thread;
152 int os::Linux::_page_size = -1;
153 bool os::Linux::_supports_fast_thread_cpu_time = false;
154 const char * os::Linux::_glibc_version = NULL;
155 const char * os::Linux::_libpthread_version = NULL;
156
157 static jlong initial_time_count=0;
158
159 static int clock_tics_per_sec = 100;
160
161 // If the VM might have been created on the primordial thread, we need to resolve the
162 // primordial thread stack bounds and check if the current thread might be the
163 // primordial thread in places. If we know that the primordial thread is never used,
164 // such as when the VM was created by one of the standard java launchers, we can
165 // avoid this
166 static bool suppress_primordial_thread_resolution = false;
167
168 // For diagnostics to print a message once. see run_periodic_checks
169 static sigset_t check_signal_done;
170 static bool check_signals = true;
171
172 // Signal number used to suspend/resume a thread
173
174 // do not use any signal number less than SIGSEGV, see 4355769
175 static int SR_signum = SIGUSR2;
176 sigset_t SR_sigset;
177
178 // utility functions
179
180 static int SR_initialize();
181
182 julong os::available_memory() {
183 return Linux::available_memory();
184 }
185
186 julong os::Linux::available_memory() {
187 // values in struct sysinfo are "unsigned long"
188 struct sysinfo si;
189 julong avail_mem;
190
191 if (OSContainer::is_containerized()) {
192 jlong mem_limit, mem_usage;
193 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
194 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
195 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
196 }
197 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
198 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
199 }
200 if (mem_limit > 0 && mem_usage > 0 ) {
201 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
202 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
203 return avail_mem;
204 }
205 }
206
207 sysinfo(&si);
208 avail_mem = (julong)si.freeram * si.mem_unit;
209 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
210 return avail_mem;
211 }
212
213 julong os::physical_memory() {
214 jlong phys_mem = 0;
215 if (OSContainer::is_containerized()) {
216 jlong mem_limit;
217 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
218 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
219 return mem_limit;
220 }
221 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
222 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
223 }
224
225 phys_mem = Linux::physical_memory();
226 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
227 return phys_mem;
228 }
229
230 static uint64_t initial_total_ticks = 0;
231 static uint64_t initial_steal_ticks = 0;
232 static bool has_initial_tick_info = false;
233
234 static void next_line(FILE *f) {
235 int c;
236 do {
237 c = fgetc(f);
238 } while (c != '\n' && c != EOF);
239 }
240
241 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
242 FILE* fh;
243 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
244 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
245 // irq: time servicing interrupts; softirq: time servicing softirqs
246 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
247 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
248 uint64_t stealTicks = 0;
249 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
250 // control of the Linux kernel
251 uint64_t guestNiceTicks = 0;
252 int logical_cpu = -1;
253 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
254 int n;
255
256 memset(pticks, 0, sizeof(CPUPerfTicks));
257
258 if ((fh = fopen("/proc/stat", "r")) == NULL) {
259 return false;
260 }
261
262 if (which_logical_cpu == -1) {
263 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
264 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " ",
266 &userTicks, &niceTicks, &systemTicks, &idleTicks,
267 &iowTicks, &irqTicks, &sirqTicks,
268 &stealTicks, &guestNiceTicks);
269 } else {
270 // Move to next line
271 next_line(fh);
272
273 // find the line for requested cpu faster to just iterate linefeeds?
274 for (int i = 0; i < which_logical_cpu; i++) {
275 next_line(fh);
276 }
277
278 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
279 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " ",
281 &logical_cpu, &userTicks, &niceTicks,
282 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
283 &stealTicks, &guestNiceTicks);
284 }
285
286 fclose(fh);
287 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
288 return false;
289 }
290 pticks->used = userTicks + niceTicks;
291 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
292 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
293 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
294
295 if (n > required_tickinfo_count + 3) {
296 pticks->steal = stealTicks;
297 pticks->has_steal_ticks = true;
298 } else {
299 pticks->steal = 0;
300 pticks->has_steal_ticks = false;
301 }
302
303 return true;
304 }
305
306 // Return true if user is running as root.
307
308 bool os::have_special_privileges() {
309 static bool init = false;
310 static bool privileges = false;
311 if (!init) {
312 privileges = (getuid() != geteuid()) || (getgid() != getegid());
313 init = true;
314 }
315 return privileges;
316 }
317
318
319 #ifndef SYS_gettid
320 // i386: 224, ia64: 1105, amd64: 186, sparc 143
321 #ifdef __ia64__
322 #define SYS_gettid 1105
323 #else
324 #ifdef __i386__
325 #define SYS_gettid 224
326 #else
327 #ifdef __amd64__
328 #define SYS_gettid 186
329 #else
330 #ifdef __sparc__
331 #define SYS_gettid 143
332 #else
333 #error define gettid for the arch
334 #endif
335 #endif
336 #endif
337 #endif
338 #endif
339
340
341 // pid_t gettid()
342 //
343 // Returns the kernel thread id of the currently running thread. Kernel
344 // thread id is used to access /proc.
345 pid_t os::Linux::gettid() {
346 int rslt = syscall(SYS_gettid);
347 assert(rslt != -1, "must be."); // old linuxthreads implementation?
348 return (pid_t)rslt;
349 }
350
351 // Most versions of linux have a bug where the number of processors are
352 // determined by looking at the /proc file system. In a chroot environment,
353 // the system call returns 1.
354 static bool unsafe_chroot_detected = false;
355 static const char *unstable_chroot_error = "/proc file system not found.\n"
356 "Java may be unstable running multithreaded in a chroot "
357 "environment on Linux when /proc filesystem is not mounted.";
358
359 void os::Linux::initialize_system_info() {
360 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
361 if (processor_count() == 1) {
362 pid_t pid = os::Linux::gettid();
363 char fname[32];
364 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
365 FILE *fp = fopen(fname, "r");
366 if (fp == NULL) {
367 unsafe_chroot_detected = true;
368 } else {
369 fclose(fp);
370 }
371 }
372 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
373 assert(processor_count() > 0, "linux error");
374 }
375
376 void os::init_system_properties_values() {
377 // The next steps are taken in the product version:
378 //
379 // Obtain the JAVA_HOME value from the location of libjvm.so.
380 // This library should be located at:
381 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
382 //
383 // If "/jre/lib/" appears at the right place in the path, then we
384 // assume libjvm.so is installed in a JDK and we use this path.
385 //
386 // Otherwise exit with message: "Could not create the Java virtual machine."
387 //
388 // The following extra steps are taken in the debugging version:
389 //
390 // If "/jre/lib/" does NOT appear at the right place in the path
391 // instead of exit check for $JAVA_HOME environment variable.
392 //
393 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
394 // then we append a fake suffix "hotspot/libjvm.so" to this path so
395 // it looks like libjvm.so is installed there
396 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
397 //
398 // Otherwise exit.
399 //
400 // Important note: if the location of libjvm.so changes this
401 // code needs to be changed accordingly.
402
403 // See ld(1):
404 // The linker uses the following search paths to locate required
405 // shared libraries:
406 // 1: ...
407 // ...
408 // 7: The default directories, normally /lib and /usr/lib.
409 #ifndef OVERRIDE_LIBPATH
410 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
411 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
412 #else
413 #define DEFAULT_LIBPATH "/lib:/usr/lib"
414 #endif
415 #else
416 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
417 #endif
418
419 // Base path of extensions installed on the system.
420 #define SYS_EXT_DIR "/usr/java/packages"
421 #define EXTENSIONS_DIR "/lib/ext"
422
423 // Buffer that fits several sprintfs.
424 // Note that the space for the colon and the trailing null are provided
425 // by the nulls included by the sizeof operator.
426 const size_t bufsize =
427 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
428 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
429 char *buf = NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
430
431 // sysclasspath, java_home, dll_dir
432 {
433 char *pslash;
434 os::jvm_path(buf, bufsize);
435
436 // Found the full path to libjvm.so.
437 // Now cut the path to <java_home>/jre if we can.
438 pslash = strrchr(buf, '/');
439 if (pslash != NULL) {
440 *pslash = '\0'; // Get rid of /libjvm.so.
441 }
442 pslash = strrchr(buf, '/');
443 if (pslash != NULL) {
444 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
445 }
446 Arguments::set_dll_dir(buf);
447
448 if (pslash != NULL) {
449 pslash = strrchr(buf, '/');
450 if (pslash != NULL) {
451 *pslash = '\0'; // Get rid of /lib.
452 }
453 }
454 Arguments::set_java_home(buf);
455 if (!set_boot_path('/', ':')) {
456 vm_exit_during_initialization("Failed setting boot class path.", NULL);
457 }
458 }
459
460 // Where to look for native libraries.
461 //
462 // Note: Due to a legacy implementation, most of the library path
463 // is set in the launcher. This was to accomodate linking restrictions
464 // on legacy Linux implementations (which are no longer supported).
465 // Eventually, all the library path setting will be done here.
466 //
467 // However, to prevent the proliferation of improperly built native
468 // libraries, the new path component /usr/java/packages is added here.
469 // Eventually, all the library path setting will be done here.
470 {
471 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
472 // should always exist (until the legacy problem cited above is
473 // addressed).
474 const char *v = ::getenv("LD_LIBRARY_PATH");
475 const char *v_colon = ":";
476 if (v == NULL) { v = ""; v_colon = ""; }
477 // That's +1 for the colon and +1 for the trailing '\0'.
478 char *ld_library_path = NEW_C_HEAP_ARRAY(char,
479 strlen(v) + 1 +
480 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
481 mtInternal);
482 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
483 Arguments::set_library_path(ld_library_path);
484 FREE_C_HEAP_ARRAY(char, ld_library_path);
485 }
486
487 // Extensions directories.
488 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
489 Arguments::set_ext_dirs(buf);
490
491 FREE_C_HEAP_ARRAY(char, buf);
492
493 #undef DEFAULT_LIBPATH
494 #undef SYS_EXT_DIR
495 #undef EXTENSIONS_DIR
496 }
497
498 ////////////////////////////////////////////////////////////////////////////////
499 // breakpoint support
500
501 void os::breakpoint() {
502 BREAKPOINT;
503 }
504
505 extern "C" void breakpoint() {
506 // use debugger to set breakpoint here
507 }
508
509 ////////////////////////////////////////////////////////////////////////////////
510 // signal support
511
512 debug_only(static bool signal_sets_initialized = false);
513 static sigset_t unblocked_sigs, vm_sigs;
514
515 void os::Linux::signal_sets_init() {
516 // Should also have an assertion stating we are still single-threaded.
517 assert(!signal_sets_initialized, "Already initialized");
518 // Fill in signals that are necessarily unblocked for all threads in
519 // the VM. Currently, we unblock the following signals:
520 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
521 // by -Xrs (=ReduceSignalUsage));
522 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
523 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
524 // the dispositions or masks wrt these signals.
525 // Programs embedding the VM that want to use the above signals for their
526 // own purposes must, at this time, use the "-Xrs" option to prevent
527 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
528 // (See bug 4345157, and other related bugs).
529 // In reality, though, unblocking these signals is really a nop, since
530 // these signals are not blocked by default.
531 sigemptyset(&unblocked_sigs);
532 sigaddset(&unblocked_sigs, SIGILL);
533 sigaddset(&unblocked_sigs, SIGSEGV);
534 sigaddset(&unblocked_sigs, SIGBUS);
535 sigaddset(&unblocked_sigs, SIGFPE);
536 #if defined(PPC64)
537 sigaddset(&unblocked_sigs, SIGTRAP);
538 #endif
539 sigaddset(&unblocked_sigs, SR_signum);
540
541 if (!ReduceSignalUsage) {
542 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
543 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
544 }
545 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
546 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
547 }
548 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
549 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
550 }
551 }
552 // Fill in signals that are blocked by all but the VM thread.
553 sigemptyset(&vm_sigs);
554 if (!ReduceSignalUsage) {
555 sigaddset(&vm_sigs, BREAK_SIGNAL);
556 }
557 debug_only(signal_sets_initialized = true);
558
559 }
560
561 // These are signals that are unblocked while a thread is running Java.
562 // (For some reason, they get blocked by default.)
563 sigset_t* os::Linux::unblocked_signals() {
564 assert(signal_sets_initialized, "Not initialized");
565 return &unblocked_sigs;
566 }
567
568 // These are the signals that are blocked while a (non-VM) thread is
569 // running Java. Only the VM thread handles these signals.
570 sigset_t* os::Linux::vm_signals() {
571 assert(signal_sets_initialized, "Not initialized");
572 return &vm_sigs;
573 }
574
575 void os::Linux::hotspot_sigmask(Thread* thread) {
576
577 //Save caller's signal mask before setting VM signal mask
578 sigset_t caller_sigmask;
579 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
580
581 OSThread* osthread = thread->osthread();
582 osthread->set_caller_sigmask(caller_sigmask);
583
584 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
585
586 if (!ReduceSignalUsage) {
587 if (thread->is_VM_thread()) {
588 // Only the VM thread handles BREAK_SIGNAL ...
589 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
590 } else {
591 // ... all other threads block BREAK_SIGNAL
592 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
593 }
594 }
595 }
596
597 //////////////////////////////////////////////////////////////////////////////
598 // detecting pthread library
599
600 void os::Linux::libpthread_init() {
601 // Save glibc and pthread version strings.
602 #if !defined(_CS_GNU_LIBC_VERSION) || \
603 !defined(_CS_GNU_LIBPTHREAD_VERSION)
604 #error "glibc too old (< 2.3.2)"
605 #endif
606
607 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
608 assert(n > 0, "cannot retrieve glibc version");
609 char *str = (char *)malloc(n, mtInternal);
610 confstr(_CS_GNU_LIBC_VERSION, str, n);
611 os::Linux::set_glibc_version(str);
612
613 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
614 assert(n > 0, "cannot retrieve pthread version");
615 str = (char *)malloc(n, mtInternal);
616 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
617 os::Linux::set_libpthread_version(str);
618 }
619
620 /////////////////////////////////////////////////////////////////////////////
621 // thread stack expansion
622
623 // os::Linux::manually_expand_stack() takes care of expanding the thread
624 // stack. Note that this is normally not needed: pthread stacks allocate
625 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
626 // committed. Therefore it is not necessary to expand the stack manually.
627 //
628 // Manually expanding the stack was historically needed on LinuxThreads
629 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
630 // it is kept to deal with very rare corner cases:
631 //
632 // For one, user may run the VM on an own implementation of threads
633 // whose stacks are - like the old LinuxThreads - implemented using
634 // mmap(MAP_GROWSDOWN).
635 //
636 // Also, this coding may be needed if the VM is running on the primordial
637 // thread. Normally we avoid running on the primordial thread; however,
638 // user may still invoke the VM on the primordial thread.
639 //
640 // The following historical comment describes the details about running
641 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
642
643
644 // Force Linux kernel to expand current thread stack. If "bottom" is close
645 // to the stack guard, caller should block all signals.
646 //
647 // MAP_GROWSDOWN:
648 // A special mmap() flag that is used to implement thread stacks. It tells
649 // kernel that the memory region should extend downwards when needed. This
650 // allows early versions of LinuxThreads to only mmap the first few pages
651 // when creating a new thread. Linux kernel will automatically expand thread
652 // stack as needed (on page faults).
653 //
654 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
655 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
656 // region, it's hard to tell if the fault is due to a legitimate stack
657 // access or because of reading/writing non-exist memory (e.g. buffer
658 // overrun). As a rule, if the fault happens below current stack pointer,
659 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
660 // application (see Linux kernel fault.c).
661 //
662 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
663 // stack overflow detection.
664 //
665 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
666 // not use MAP_GROWSDOWN.
667 //
668 // To get around the problem and allow stack banging on Linux, we need to
669 // manually expand thread stack after receiving the SIGSEGV.
670 //
671 // There are two ways to expand thread stack to address "bottom", we used
672 // both of them in JVM before 1.5:
673 // 1. adjust stack pointer first so that it is below "bottom", and then
674 // touch "bottom"
675 // 2. mmap() the page in question
676 //
677 // Now alternate signal stack is gone, it's harder to use 2. For instance,
678 // if current sp is already near the lower end of page 101, and we need to
679 // call mmap() to map page 100, it is possible that part of the mmap() frame
680 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
681 // That will destroy the mmap() frame and cause VM to crash.
682 //
683 // The following code works by adjusting sp first, then accessing the "bottom"
684 // page to force a page fault. Linux kernel will then automatically expand the
685 // stack mapping.
686 //
687 // _expand_stack_to() assumes its frame size is less than page size, which
688 // should always be true if the function is not inlined.
689
690 static void NOINLINE _expand_stack_to(address bottom) {
691 address sp;
692 size_t size;
693 volatile char *p;
694
695 // Adjust bottom to point to the largest address within the same page, it
696 // gives us a one-page buffer if alloca() allocates slightly more memory.
697 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
698 bottom += os::Linux::page_size() - 1;
699
700 // sp might be slightly above current stack pointer; if that's the case, we
701 // will alloca() a little more space than necessary, which is OK. Don't use
702 // os::current_stack_pointer(), as its result can be slightly below current
703 // stack pointer, causing us to not alloca enough to reach "bottom".
704 sp = (address)&sp;
705
706 if (sp > bottom) {
707 size = sp - bottom;
708 p = (volatile char *)alloca(size);
709 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
710 p[0] = '\0';
711 }
712 }
713
714 void os::Linux::expand_stack_to(address bottom) {
715 _expand_stack_to(bottom);
716 }
717
718 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
719 assert(t!=NULL, "just checking");
720 assert(t->osthread()->expanding_stack(), "expand should be set");
721 assert(t->stack_base() != NULL, "stack_base was not initialized");
722
723 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
724 sigset_t mask_all, old_sigset;
725 sigfillset(&mask_all);
726 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
727 _expand_stack_to(addr);
728 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
729 return true;
730 }
731 return false;
732 }
733
734 //////////////////////////////////////////////////////////////////////////////
735 // create new thread
736
737 // Thread start routine for all newly created threads
738 static void *thread_native_entry(Thread *thread) {
739
740 thread->record_stack_base_and_size();
741
742 // Try to randomize the cache line index of hot stack frames.
743 // This helps when threads of the same stack traces evict each other's
744 // cache lines. The threads can be either from the same JVM instance, or
745 // from different JVM instances. The benefit is especially true for
746 // processors with hyperthreading technology.
747 static int counter = 0;
748 int pid = os::current_process_id();
749 alloca(((pid ^ counter++) & 7) * 128);
750
751 thread->initialize_thread_current();
752
753 OSThread* osthread = thread->osthread();
754 Monitor* sync = osthread->startThread_lock();
755
756 osthread->set_thread_id(os::current_thread_id());
757
758 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
759 os::current_thread_id(), (uintx) pthread_self());
760
761 if (UseNUMA) {
762 int lgrp_id = os::numa_get_group_id();
763 if (lgrp_id != -1) {
764 thread->set_lgrp_id(lgrp_id);
765 }
766 }
767 // initialize signal mask for this thread
768 os::Linux::hotspot_sigmask(thread);
769
770 // initialize floating point control register
771 os::Linux::init_thread_fpu_state();
772
773 // handshaking with parent thread
774 {
775 MutexLocker ml(sync, Mutex::_no_safepoint_check_flag);
776
777 // notify parent thread
778 osthread->set_state(INITIALIZED);
779 sync->notify_all();
780
781 // wait until os::start_thread()
782 while (osthread->get_state() == INITIALIZED) {
783 sync->wait_without_safepoint_check();
784 }
785 }
786
787 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
788
789 // call one more level start routine
790 thread->call_run();
791
792 // Note: at this point the thread object may already have deleted itself.
793 // Prevent dereferencing it from here on out.
794 thread = NULL;
795
796 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
797 os::current_thread_id(), (uintx) pthread_self());
798
799 return 0;
800 }
801
802 // On Linux, glibc places static TLS blocks (for __thread variables) on
803 // the thread stack. This decreases the stack size actually available
804 // to threads.
805 //
806 // For large static TLS sizes, this may cause threads to malfunction due
807 // to insufficient stack space. This is a well-known issue in glibc:
808 // http://sourceware.org/bugzilla/show_bug.cgi?id=11787.
809 //
810 // As a workaround, we call a private but assumed-stable glibc function,
811 // __pthread_get_minstack() to obtain the minstack size and derive the
812 // static TLS size from it. We then increase the user requested stack
813 // size by this TLS size.
814 //
815 // Due to compatibility concerns, this size adjustment is opt-in and
816 // controlled via AdjustStackSizeForTLS.
817 typedef size_t (*GetMinStack)(const pthread_attr_t *attr);
818
819 GetMinStack _get_minstack_func = NULL;
820
821 static void get_minstack_init() {
822 _get_minstack_func =
823 (GetMinStack)dlsym(RTLD_DEFAULT, "__pthread_get_minstack");
824 log_info(os, thread)("Lookup of __pthread_get_minstack %s",
825 _get_minstack_func == NULL ? "failed" : "succeeded");
826 }
827
828 // Returns the size of the static TLS area glibc puts on thread stacks.
829 // The value is cached on first use, which occurs when the first thread
830 // is created during VM initialization.
831 static size_t get_static_tls_area_size(const pthread_attr_t *attr) {
832 size_t tls_size = 0;
833 if (_get_minstack_func != NULL) {
834 // Obtain the pthread minstack size by calling __pthread_get_minstack.
835 size_t minstack_size = _get_minstack_func(attr);
836
837 // Remove non-TLS area size included in minstack size returned
838 // by __pthread_get_minstack() to get the static TLS size.
839 // In glibc before 2.27, minstack size includes guard_size.
840 // In glibc 2.27 and later, guard_size is automatically added
841 // to the stack size by pthread_create and is no longer included
842 // in minstack size. In both cases, the guard_size is taken into
843 // account, so there is no need to adjust the result for that.
844 //
845 // Although __pthread_get_minstack() is a private glibc function,
846 // it is expected to have a stable behavior across future glibc
847 // versions while glibc still allocates the static TLS blocks off
848 // the stack. Following is glibc 2.28 __pthread_get_minstack():
849 //
850 // size_t
851 // __pthread_get_minstack (const pthread_attr_t *attr)
852 // {
853 // return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
854 // }
855 //
856 //
857 // The following 'minstack_size > os::vm_page_size() + PTHREAD_STACK_MIN'
858 // if check is done for precaution.
859 if (minstack_size > (size_t)os::vm_page_size() + PTHREAD_STACK_MIN) {
860 tls_size = minstack_size - os::vm_page_size() - PTHREAD_STACK_MIN;
861 }
862 }
863
864 log_info(os, thread)("Stack size adjustment for TLS is " SIZE_FORMAT,
865 tls_size);
866 return tls_size;
867 }
868
869 bool os::create_thread(Thread* thread, ThreadType thr_type,
870 size_t req_stack_size) {
871 assert(thread->osthread() == NULL, "caller responsible");
872
873 // Allocate the OSThread object
874 OSThread* osthread = new OSThread(NULL, NULL);
875 if (osthread == NULL) {
876 return false;
877 }
878
879 // set the correct thread state
880 osthread->set_thread_type(thr_type);
881
882 // Initial state is ALLOCATED but not INITIALIZED
883 osthread->set_state(ALLOCATED);
884
885 thread->set_osthread(osthread);
886
887 // init thread attributes
888 pthread_attr_t attr;
889 pthread_attr_init(&attr);
890 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
891
892 // Calculate stack size if it's not specified by caller.
893 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
894 // In glibc versions prior to 2.7 the guard size mechanism
895 // is not implemented properly. The posix standard requires adding
896 // the size of the guard pages to the stack size, instead Linux
897 // takes the space out of 'stacksize'. Thus we adapt the requested
898 // stack_size by the size of the guard pages to mimick proper
899 // behaviour. However, be careful not to end up with a size
900 // of zero due to overflow. Don't add the guard page in that case.
901 size_t guard_size = os::Linux::default_guard_size(thr_type);
902 // Configure glibc guard page. Must happen before calling
903 // get_static_tls_area_size(), which uses the guard_size.
904 pthread_attr_setguardsize(&attr, guard_size);
905
906 size_t stack_adjust_size = 0;
907 if (AdjustStackSizeForTLS) {
908 // Adjust the stack_size for on-stack TLS - see get_static_tls_area_size().
909 stack_adjust_size += get_static_tls_area_size(&attr);
910 } else {
911 stack_adjust_size += guard_size;
912 }
913
914 stack_adjust_size = align_up(stack_adjust_size, os::vm_page_size());
915 if (stack_size <= SIZE_MAX - stack_adjust_size) {
916 stack_size += stack_adjust_size;
917 }
918 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
919
920 int status = pthread_attr_setstacksize(&attr, stack_size);
921 assert_status(status == 0, status, "pthread_attr_setstacksize");
922
923 ThreadState state;
924
925 {
926 pthread_t tid;
927 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
928
929 char buf[64];
930 if (ret == 0) {
931 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
932 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
933 } else {
934 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
935 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
936 // Log some OS information which might explain why creating the thread failed.
937 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
938 LogStream st(Log(os, thread)::info());
939 os::Posix::print_rlimit_info(&st);
940 os::print_memory_info(&st);
941 os::Linux::print_proc_sys_info(&st);
942 os::Linux::print_container_info(&st);
943 }
944
945 pthread_attr_destroy(&attr);
946
947 if (ret != 0) {
948 // Need to clean up stuff we've allocated so far
949 thread->set_osthread(NULL);
950 delete osthread;
951 return false;
952 }
953
954 // Store pthread info into the OSThread
955 osthread->set_pthread_id(tid);
956
957 // Wait until child thread is either initialized or aborted
958 {
959 Monitor* sync_with_child = osthread->startThread_lock();
960 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
961 while ((state = osthread->get_state()) == ALLOCATED) {
962 sync_with_child->wait_without_safepoint_check();
963 }
964 }
965 }
966
967 // Aborted due to thread limit being reached
968 if (state == ZOMBIE) {
969 thread->set_osthread(NULL);
970 delete osthread;
971 return false;
972 }
973
974 // The thread is returned suspended (in state INITIALIZED),
975 // and is started higher up in the call chain
976 assert(state == INITIALIZED, "race condition");
977 return true;
978 }
979
980 /////////////////////////////////////////////////////////////////////////////
981 // attach existing thread
982
983 // bootstrap the main thread
984 bool os::create_main_thread(JavaThread* thread) {
985 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
986 return create_attached_thread(thread);
987 }
988
989 bool os::create_attached_thread(JavaThread* thread) {
990 #ifdef ASSERT
991 thread->verify_not_published();
992 #endif
993
994 // Allocate the OSThread object
995 OSThread* osthread = new OSThread(NULL, NULL);
996
997 if (osthread == NULL) {
998 return false;
999 }
1000
1001 // Store pthread info into the OSThread
1002 osthread->set_thread_id(os::Linux::gettid());
1003 osthread->set_pthread_id(::pthread_self());
1004
1005 // initialize floating point control register
1006 os::Linux::init_thread_fpu_state();
1007
1008 // Initial thread state is RUNNABLE
1009 osthread->set_state(RUNNABLE);
1010
1011 thread->set_osthread(osthread);
1012
1013 if (UseNUMA) {
1014 int lgrp_id = os::numa_get_group_id();
1015 if (lgrp_id != -1) {
1016 thread->set_lgrp_id(lgrp_id);
1017 }
1018 }
1019
1020 if (os::is_primordial_thread()) {
1021 // If current thread is primordial thread, its stack is mapped on demand,
1022 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1023 // the entire stack region to avoid SEGV in stack banging.
1024 // It is also useful to get around the heap-stack-gap problem on SuSE
1025 // kernel (see 4821821 for details). We first expand stack to the top
1026 // of yellow zone, then enable stack yellow zone (order is significant,
1027 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1028 // is no gap between the last two virtual memory regions.
1029
1030 JavaThread *jt = (JavaThread *)thread;
1031 address addr = jt->stack_reserved_zone_base();
1032 assert(addr != NULL, "initialization problem?");
1033 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1034
1035 osthread->set_expanding_stack();
1036 os::Linux::manually_expand_stack(jt, addr);
1037 osthread->clear_expanding_stack();
1038 }
1039
1040 // initialize signal mask for this thread
1041 // and save the caller's signal mask
1042 os::Linux::hotspot_sigmask(thread);
1043
1044 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
1045 os::current_thread_id(), (uintx) pthread_self());
1046
1047 return true;
1048 }
1049
1050 void os::pd_start_thread(Thread* thread) {
1051 OSThread * osthread = thread->osthread();
1052 assert(osthread->get_state() != INITIALIZED, "just checking");
1053 Monitor* sync_with_child = osthread->startThread_lock();
1054 MutexLocker ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1055 sync_with_child->notify();
1056 }
1057
1058 // Free Linux resources related to the OSThread
1059 void os::free_thread(OSThread* osthread) {
1060 assert(osthread != NULL, "osthread not set");
1061
1062 // We are told to free resources of the argument thread,
1063 // but we can only really operate on the current thread.
1064 assert(Thread::current()->osthread() == osthread,
1065 "os::free_thread but not current thread");
1066
1067 #ifdef ASSERT
1068 sigset_t current;
1069 sigemptyset(¤t);
1070 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
1071 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
1072 #endif
1073
1074 // Restore caller's signal mask
1075 sigset_t sigmask = osthread->caller_sigmask();
1076 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1077
1078 delete osthread;
1079 }
1080
1081 //////////////////////////////////////////////////////////////////////////////
1082 // primordial thread
1083
1084 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1085 bool os::is_primordial_thread(void) {
1086 if (suppress_primordial_thread_resolution) {
1087 return false;
1088 }
1089 char dummy;
1090 // If called before init complete, thread stack bottom will be null.
1091 // Can be called if fatal error occurs before initialization.
1092 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1093 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1094 os::Linux::initial_thread_stack_size() != 0,
1095 "os::init did not locate primordial thread's stack region");
1096 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1097 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1098 os::Linux::initial_thread_stack_size()) {
1099 return true;
1100 } else {
1101 return false;
1102 }
1103 }
1104
1105 // Find the virtual memory area that contains addr
1106 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1107 FILE *fp = fopen("/proc/self/maps", "r");
1108 if (fp) {
1109 address low, high;
1110 while (!feof(fp)) {
1111 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1112 if (low <= addr && addr < high) {
1113 if (vma_low) *vma_low = low;
1114 if (vma_high) *vma_high = high;
1115 fclose(fp);
1116 return true;
1117 }
1118 }
1119 for (;;) {
1120 int ch = fgetc(fp);
1121 if (ch == EOF || ch == (int)'\n') break;
1122 }
1123 }
1124 fclose(fp);
1125 }
1126 return false;
1127 }
1128
1129 // Locate primordial thread stack. This special handling of primordial thread stack
1130 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1131 // bogus value for the primordial process thread. While the launcher has created
1132 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1133 // JNI invocation API from a primordial thread.
1134 void os::Linux::capture_initial_stack(size_t max_size) {
1135
1136 // max_size is either 0 (which means accept OS default for thread stacks) or
1137 // a user-specified value known to be at least the minimum needed. If we
1138 // are actually on the primordial thread we can make it appear that we have a
1139 // smaller max_size stack by inserting the guard pages at that location. But we
1140 // cannot do anything to emulate a larger stack than what has been provided by
1141 // the OS or threading library. In fact if we try to use a stack greater than
1142 // what is set by rlimit then we will crash the hosting process.
1143
1144 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1145 // If this is "unlimited" then it will be a huge value.
1146 struct rlimit rlim;
1147 getrlimit(RLIMIT_STACK, &rlim);
1148 size_t stack_size = rlim.rlim_cur;
1149
1150 // 6308388: a bug in ld.so will relocate its own .data section to the
1151 // lower end of primordial stack; reduce ulimit -s value a little bit
1152 // so we won't install guard page on ld.so's data section.
1153 // But ensure we don't underflow the stack size - allow 1 page spare
1154 if (stack_size >= (size_t)(3 * page_size())) {
1155 stack_size -= 2 * page_size();
1156 }
1157
1158 // Try to figure out where the stack base (top) is. This is harder.
1159 //
1160 // When an application is started, glibc saves the initial stack pointer in
1161 // a global variable "__libc_stack_end", which is then used by system
1162 // libraries. __libc_stack_end should be pretty close to stack top. The
1163 // variable is available since the very early days. However, because it is
1164 // a private interface, it could disappear in the future.
1165 //
1166 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1167 // to __libc_stack_end, it is very close to stack top, but isn't the real
1168 // stack top. Note that /proc may not exist if VM is running as a chroot
1169 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1170 // /proc/<pid>/stat could change in the future (though unlikely).
1171 //
1172 // We try __libc_stack_end first. If that doesn't work, look for
1173 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1174 // as a hint, which should work well in most cases.
1175
1176 uintptr_t stack_start;
1177
1178 // try __libc_stack_end first
1179 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1180 if (p && *p) {
1181 stack_start = *p;
1182 } else {
1183 // see if we can get the start_stack field from /proc/self/stat
1184 FILE *fp;
1185 int pid;
1186 char state;
1187 int ppid;
1188 int pgrp;
1189 int session;
1190 int nr;
1191 int tpgrp;
1192 unsigned long flags;
1193 unsigned long minflt;
1194 unsigned long cminflt;
1195 unsigned long majflt;
1196 unsigned long cmajflt;
1197 unsigned long utime;
1198 unsigned long stime;
1199 long cutime;
1200 long cstime;
1201 long prio;
1202 long nice;
1203 long junk;
1204 long it_real;
1205 uintptr_t start;
1206 uintptr_t vsize;
1207 intptr_t rss;
1208 uintptr_t rsslim;
1209 uintptr_t scodes;
1210 uintptr_t ecode;
1211 int i;
1212
1213 // Figure what the primordial thread stack base is. Code is inspired
1214 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1215 // followed by command name surrounded by parentheses, state, etc.
1216 char stat[2048];
1217 int statlen;
1218
1219 fp = fopen("/proc/self/stat", "r");
1220 if (fp) {
1221 statlen = fread(stat, 1, 2047, fp);
1222 stat[statlen] = '\0';
1223 fclose(fp);
1224
1225 // Skip pid and the command string. Note that we could be dealing with
1226 // weird command names, e.g. user could decide to rename java launcher
1227 // to "java 1.4.2 :)", then the stat file would look like
1228 // 1234 (java 1.4.2 :)) R ... ...
1229 // We don't really need to know the command string, just find the last
1230 // occurrence of ")" and then start parsing from there. See bug 4726580.
1231 char * s = strrchr(stat, ')');
1232
1233 i = 0;
1234 if (s) {
1235 // Skip blank chars
1236 do { s++; } while (s && isspace(*s));
1237
1238 #define _UFM UINTX_FORMAT
1239 #define _DFM INTX_FORMAT
1240
1241 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1242 // 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8
1243 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1244 &state, // 3 %c
1245 &ppid, // 4 %d
1246 &pgrp, // 5 %d
1247 &session, // 6 %d
1248 &nr, // 7 %d
1249 &tpgrp, // 8 %d
1250 &flags, // 9 %lu
1251 &minflt, // 10 %lu
1252 &cminflt, // 11 %lu
1253 &majflt, // 12 %lu
1254 &cmajflt, // 13 %lu
1255 &utime, // 14 %lu
1256 &stime, // 15 %lu
1257 &cutime, // 16 %ld
1258 &cstime, // 17 %ld
1259 &prio, // 18 %ld
1260 &nice, // 19 %ld
1261 &junk, // 20 %ld
1262 &it_real, // 21 %ld
1263 &start, // 22 UINTX_FORMAT
1264 &vsize, // 23 UINTX_FORMAT
1265 &rss, // 24 INTX_FORMAT
1266 &rsslim, // 25 UINTX_FORMAT
1267 &scodes, // 26 UINTX_FORMAT
1268 &ecode, // 27 UINTX_FORMAT
1269 &stack_start); // 28 UINTX_FORMAT
1270 }
1271
1272 #undef _UFM
1273 #undef _DFM
1274
1275 if (i != 28 - 2) {
1276 assert(false, "Bad conversion from /proc/self/stat");
1277 // product mode - assume we are the primordial thread, good luck in the
1278 // embedded case.
1279 warning("Can't detect primordial thread stack location - bad conversion");
1280 stack_start = (uintptr_t) &rlim;
1281 }
1282 } else {
1283 // For some reason we can't open /proc/self/stat (for example, running on
1284 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1285 // most cases, so don't abort:
1286 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1287 stack_start = (uintptr_t) &rlim;
1288 }
1289 }
1290
1291 // Now we have a pointer (stack_start) very close to the stack top, the
1292 // next thing to do is to figure out the exact location of stack top. We
1293 // can find out the virtual memory area that contains stack_start by
1294 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1295 // and its upper limit is the real stack top. (again, this would fail if
1296 // running inside chroot, because /proc may not exist.)
1297
1298 uintptr_t stack_top;
1299 address low, high;
1300 if (find_vma((address)stack_start, &low, &high)) {
1301 // success, "high" is the true stack top. (ignore "low", because initial
1302 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1303 stack_top = (uintptr_t)high;
1304 } else {
1305 // failed, likely because /proc/self/maps does not exist
1306 warning("Can't detect primordial thread stack location - find_vma failed");
1307 // best effort: stack_start is normally within a few pages below the real
1308 // stack top, use it as stack top, and reduce stack size so we won't put
1309 // guard page outside stack.
1310 stack_top = stack_start;
1311 stack_size -= 16 * page_size();
1312 }
1313
1314 // stack_top could be partially down the page so align it
1315 stack_top = align_up(stack_top, page_size());
1316
1317 // Allowed stack value is minimum of max_size and what we derived from rlimit
1318 if (max_size > 0) {
1319 _initial_thread_stack_size = MIN2(max_size, stack_size);
1320 } else {
1321 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1322 // clamp it at 8MB as we do on Solaris
1323 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1324 }
1325 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1326 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1327
1328 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1329
1330 if (log_is_enabled(Info, os, thread)) {
1331 // See if we seem to be on primordial process thread
1332 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1333 uintptr_t(&rlim) < stack_top;
1334
1335 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1336 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1337 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1338 stack_top, intptr_t(_initial_thread_stack_bottom));
1339 }
1340 }
1341
1342 ////////////////////////////////////////////////////////////////////////////////
1343 // time support
1344
1345 #ifndef SUPPORTS_CLOCK_MONOTONIC
1346 #error "Build platform doesn't support clock_gettime and related functionality"
1347 #endif
1348
1349 // Time since start-up in seconds to a fine granularity.
1350 // Used by VMSelfDestructTimer and the MemProfiler.
1351 double os::elapsedTime() {
1352
1353 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1354 }
1355
1356 jlong os::elapsed_counter() {
1357 return javaTimeNanos() - initial_time_count;
1358 }
1359
1360 jlong os::elapsed_frequency() {
1361 return NANOSECS_PER_SEC; // nanosecond resolution
1362 }
1363
1364 bool os::supports_vtime() { return true; }
1365
1366 double os::elapsedVTime() {
1367 struct rusage usage;
1368 int retval = getrusage(RUSAGE_THREAD, &usage);
1369 if (retval == 0) {
1370 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1371 } else {
1372 // better than nothing, but not much
1373 return elapsedTime();
1374 }
1375 }
1376
1377 jlong os::javaTimeMillis() {
1378 timeval time;
1379 int status = gettimeofday(&time, NULL);
1380 assert(status != -1, "linux error");
1381 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1382 }
1383
1384 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1385 timeval time;
1386 int status = gettimeofday(&time, NULL);
1387 assert(status != -1, "linux error");
1388 seconds = jlong(time.tv_sec);
1389 nanos = jlong(time.tv_usec) * 1000;
1390 }
1391
1392 void os::Linux::fast_thread_clock_init() {
1393 if (!UseLinuxPosixThreadCPUClocks) {
1394 return;
1395 }
1396 clockid_t clockid;
1397 struct timespec tp;
1398 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1399 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1400
1401 // Switch to using fast clocks for thread cpu time if
1402 // the clock_getres() returns 0 error code.
1403 // Note, that some kernels may support the current thread
1404 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1405 // returned by the pthread_getcpuclockid().
1406 // If the fast Posix clocks are supported then the clock_getres()
1407 // must return at least tp.tv_sec == 0 which means a resolution
1408 // better than 1 sec. This is extra check for reliability.
1409
1410 if (pthread_getcpuclockid_func &&
1411 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1412 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1413 _supports_fast_thread_cpu_time = true;
1414 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1415 }
1416 }
1417
1418 jlong os::javaTimeNanos() {
1419 if (os::supports_monotonic_clock()) {
1420 struct timespec tp;
1421 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1422 assert(status == 0, "gettime error");
1423 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1424 return result;
1425 } else {
1426 timeval time;
1427 int status = gettimeofday(&time, NULL);
1428 assert(status != -1, "linux error");
1429 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1430 return 1000 * usecs;
1431 }
1432 }
1433
1434 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1435 if (os::supports_monotonic_clock()) {
1436 info_ptr->max_value = ALL_64_BITS;
1437
1438 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1439 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1440 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1441 } else {
1442 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1443 info_ptr->max_value = ALL_64_BITS;
1444
1445 // gettimeofday is a real time clock so it skips
1446 info_ptr->may_skip_backward = true;
1447 info_ptr->may_skip_forward = true;
1448 }
1449
1450 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1451 }
1452
1453 // Return the real, user, and system times in seconds from an
1454 // arbitrary fixed point in the past.
1455 bool os::getTimesSecs(double* process_real_time,
1456 double* process_user_time,
1457 double* process_system_time) {
1458 struct tms ticks;
1459 clock_t real_ticks = times(&ticks);
1460
1461 if (real_ticks == (clock_t) (-1)) {
1462 return false;
1463 } else {
1464 double ticks_per_second = (double) clock_tics_per_sec;
1465 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1466 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1467 *process_real_time = ((double) real_ticks) / ticks_per_second;
1468
1469 return true;
1470 }
1471 }
1472
1473
1474 char * os::local_time_string(char *buf, size_t buflen) {
1475 struct tm t;
1476 time_t long_time;
1477 time(&long_time);
1478 localtime_r(&long_time, &t);
1479 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1480 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1481 t.tm_hour, t.tm_min, t.tm_sec);
1482 return buf;
1483 }
1484
1485 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1486 return localtime_r(clock, res);
1487 }
1488
1489 ////////////////////////////////////////////////////////////////////////////////
1490 // runtime exit support
1491
1492 // Note: os::shutdown() might be called very early during initialization, or
1493 // called from signal handler. Before adding something to os::shutdown(), make
1494 // sure it is async-safe and can handle partially initialized VM.
1495 void os::shutdown() {
1496
1497 // allow PerfMemory to attempt cleanup of any persistent resources
1498 perfMemory_exit();
1499
1500 // needs to remove object in file system
1501 AttachListener::abort();
1502
1503 // flush buffered output, finish log files
1504 ostream_abort();
1505
1506 // Check for abort hook
1507 abort_hook_t abort_hook = Arguments::abort_hook();
1508 if (abort_hook != NULL) {
1509 abort_hook();
1510 }
1511
1512 }
1513
1514 // Note: os::abort() might be called very early during initialization, or
1515 // called from signal handler. Before adding something to os::abort(), make
1516 // sure it is async-safe and can handle partially initialized VM.
1517 void os::abort(bool dump_core, void* siginfo, const void* context) {
1518 os::shutdown();
1519 if (dump_core) {
1520 if (DumpPrivateMappingsInCore) {
1521 ClassLoader::close_jrt_image();
1522 }
1523 #ifndef PRODUCT
1524 fdStream out(defaultStream::output_fd());
1525 out.print_raw("Current thread is ");
1526 char buf[16];
1527 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1528 out.print_raw_cr(buf);
1529 out.print_raw_cr("Dumping core ...");
1530 #endif
1531 ::abort(); // dump core
1532 }
1533
1534 ::exit(1);
1535 }
1536
1537 // Die immediately, no exit hook, no abort hook, no cleanup.
1538 // Dump a core file, if possible, for debugging.
1539 void os::die() {
1540 if (TestUnresponsiveErrorHandler && !CreateCoredumpOnCrash) {
1541 // For TimeoutInErrorHandlingTest.java, we just kill the VM
1542 // and don't take the time to generate a core file.
1543 os::signal_raise(SIGKILL);
1544 } else {
1545 ::abort();
1546 }
1547 }
1548
1549 // thread_id is kernel thread id (similar to Solaris LWP id)
1550 intx os::current_thread_id() { return os::Linux::gettid(); }
1551 int os::current_process_id() {
1552 return ::getpid();
1553 }
1554
1555 // DLL functions
1556
1557 const char* os::dll_file_extension() { return ".so"; }
1558
1559 // This must be hard coded because it's the system's temporary
1560 // directory not the java application's temp directory, ala java.io.tmpdir.
1561 const char* os::get_temp_directory() { return "/tmp"; }
1562
1563 static bool file_exists(const char* filename) {
1564 struct stat statbuf;
1565 if (filename == NULL || strlen(filename) == 0) {
1566 return false;
1567 }
1568 return os::stat(filename, &statbuf) == 0;
1569 }
1570
1571 // check if addr is inside libjvm.so
1572 bool os::address_is_in_vm(address addr) {
1573 static address libjvm_base_addr;
1574 Dl_info dlinfo;
1575
1576 if (libjvm_base_addr == NULL) {
1577 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1578 libjvm_base_addr = (address)dlinfo.dli_fbase;
1579 }
1580 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1581 }
1582
1583 if (dladdr((void *)addr, &dlinfo) != 0) {
1584 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1585 }
1586
1587 return false;
1588 }
1589
1590 bool os::dll_address_to_function_name(address addr, char *buf,
1591 int buflen, int *offset,
1592 bool demangle) {
1593 // buf is not optional, but offset is optional
1594 assert(buf != NULL, "sanity check");
1595
1596 Dl_info dlinfo;
1597
1598 if (dladdr((void*)addr, &dlinfo) != 0) {
1599 // see if we have a matching symbol
1600 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1601 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1602 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1603 }
1604 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1605 return true;
1606 }
1607 // no matching symbol so try for just file info
1608 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1609 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1610 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1611 return true;
1612 }
1613 }
1614 }
1615
1616 buf[0] = '\0';
1617 if (offset != NULL) *offset = -1;
1618 return false;
1619 }
1620
1621 struct _address_to_library_name {
1622 address addr; // input : memory address
1623 size_t buflen; // size of fname
1624 char* fname; // output: library name
1625 address base; // library base addr
1626 };
1627
1628 static int address_to_library_name_callback(struct dl_phdr_info *info,
1629 size_t size, void *data) {
1630 int i;
1631 bool found = false;
1632 address libbase = NULL;
1633 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1634
1635 // iterate through all loadable segments
1636 for (i = 0; i < info->dlpi_phnum; i++) {
1637 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1638 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1639 // base address of a library is the lowest address of its loaded
1640 // segments.
1641 if (libbase == NULL || libbase > segbase) {
1642 libbase = segbase;
1643 }
1644 // see if 'addr' is within current segment
1645 if (segbase <= d->addr &&
1646 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1647 found = true;
1648 }
1649 }
1650 }
1651
1652 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1653 // so dll_address_to_library_name() can fall through to use dladdr() which
1654 // can figure out executable name from argv[0].
1655 if (found && info->dlpi_name && info->dlpi_name[0]) {
1656 d->base = libbase;
1657 if (d->fname) {
1658 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1659 }
1660 return 1;
1661 }
1662 return 0;
1663 }
1664
1665 bool os::dll_address_to_library_name(address addr, char* buf,
1666 int buflen, int* offset) {
1667 // buf is not optional, but offset is optional
1668 assert(buf != NULL, "sanity check");
1669
1670 Dl_info dlinfo;
1671 struct _address_to_library_name data;
1672
1673 // There is a bug in old glibc dladdr() implementation that it could resolve
1674 // to wrong library name if the .so file has a base address != NULL. Here
1675 // we iterate through the program headers of all loaded libraries to find
1676 // out which library 'addr' really belongs to. This workaround can be
1677 // removed once the minimum requirement for glibc is moved to 2.3.x.
1678 data.addr = addr;
1679 data.fname = buf;
1680 data.buflen = buflen;
1681 data.base = NULL;
1682 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1683
1684 if (rslt) {
1685 // buf already contains library name
1686 if (offset) *offset = addr - data.base;
1687 return true;
1688 }
1689 if (dladdr((void*)addr, &dlinfo) != 0) {
1690 if (dlinfo.dli_fname != NULL) {
1691 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1692 }
1693 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1694 *offset = addr - (address)dlinfo.dli_fbase;
1695 }
1696 return true;
1697 }
1698
1699 buf[0] = '\0';
1700 if (offset) *offset = -1;
1701 return false;
1702 }
1703
1704 // Loads .dll/.so and
1705 // in case of error it checks if .dll/.so was built for the
1706 // same architecture as Hotspot is running on
1707
1708
1709 // Remember the stack's state. The Linux dynamic linker will change
1710 // the stack to 'executable' at most once, so we must safepoint only once.
1711 bool os::Linux::_stack_is_executable = false;
1712
1713 // VM operation that loads a library. This is necessary if stack protection
1714 // of the Java stacks can be lost during loading the library. If we
1715 // do not stop the Java threads, they can stack overflow before the stacks
1716 // are protected again.
1717 class VM_LinuxDllLoad: public VM_Operation {
1718 private:
1719 const char *_filename;
1720 char *_ebuf;
1721 int _ebuflen;
1722 void *_lib;
1723 public:
1724 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1725 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1726 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1727 void doit() {
1728 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1729 os::Linux::_stack_is_executable = true;
1730 }
1731 void* loaded_library() { return _lib; }
1732 };
1733
1734 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1735 void * result = NULL;
1736 bool load_attempted = false;
1737
1738 log_info(os)("attempting shared library load of %s", filename);
1739
1740 // Check whether the library to load might change execution rights
1741 // of the stack. If they are changed, the protection of the stack
1742 // guard pages will be lost. We need a safepoint to fix this.
1743 //
1744 // See Linux man page execstack(8) for more info.
1745 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1746 if (!ElfFile::specifies_noexecstack(filename)) {
1747 if (!is_init_completed()) {
1748 os::Linux::_stack_is_executable = true;
1749 // This is OK - No Java threads have been created yet, and hence no
1750 // stack guard pages to fix.
1751 //
1752 // Dynamic loader will make all stacks executable after
1753 // this function returns, and will not do that again.
1754 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1755 } else {
1756 warning("You have loaded library %s which might have disabled stack guard. "
1757 "The VM will try to fix the stack guard now.\n"
1758 "It's highly recommended that you fix the library with "
1759 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1760 filename);
1761
1762 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1763 JavaThread *jt = JavaThread::current();
1764 if (jt->thread_state() != _thread_in_native) {
1765 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1766 // that requires ExecStack. Cannot enter safe point. Let's give up.
1767 warning("Unable to fix stack guard. Giving up.");
1768 } else {
1769 if (!LoadExecStackDllInVMThread) {
1770 // This is for the case where the DLL has an static
1771 // constructor function that executes JNI code. We cannot
1772 // load such DLLs in the VMThread.
1773 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1774 }
1775
1776 ThreadInVMfromNative tiv(jt);
1777 debug_only(VMNativeEntryWrapper vew;)
1778
1779 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1780 VMThread::execute(&op);
1781 if (LoadExecStackDllInVMThread) {
1782 result = op.loaded_library();
1783 }
1784 load_attempted = true;
1785 }
1786 }
1787 }
1788 }
1789
1790 if (!load_attempted) {
1791 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1792 }
1793
1794 if (result != NULL) {
1795 // Successful loading
1796 return result;
1797 }
1798
1799 Elf32_Ehdr elf_head;
1800 int diag_msg_max_length=ebuflen-strlen(ebuf);
1801 char* diag_msg_buf=ebuf+strlen(ebuf);
1802
1803 if (diag_msg_max_length==0) {
1804 // No more space in ebuf for additional diagnostics message
1805 return NULL;
1806 }
1807
1808
1809 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1810
1811 if (file_descriptor < 0) {
1812 // Can't open library, report dlerror() message
1813 return NULL;
1814 }
1815
1816 bool failed_to_read_elf_head=
1817 (sizeof(elf_head)!=
1818 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1819
1820 ::close(file_descriptor);
1821 if (failed_to_read_elf_head) {
1822 // file i/o error - report dlerror() msg
1823 return NULL;
1824 }
1825
1826 if (elf_head.e_ident[EI_DATA] != LITTLE_ENDIAN_ONLY(ELFDATA2LSB) BIG_ENDIAN_ONLY(ELFDATA2MSB)) {
1827 // handle invalid/out of range endianness values
1828 if (elf_head.e_ident[EI_DATA] == 0 || elf_head.e_ident[EI_DATA] > 2) {
1829 return NULL;
1830 }
1831
1832 #if defined(VM_LITTLE_ENDIAN)
1833 // VM is LE, shared object BE
1834 elf_head.e_machine = be16toh(elf_head.e_machine);
1835 #else
1836 // VM is BE, shared object LE
1837 elf_head.e_machine = le16toh(elf_head.e_machine);
1838 #endif
1839 }
1840
1841 typedef struct {
1842 Elf32_Half code; // Actual value as defined in elf.h
1843 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1844 unsigned char elf_class; // 32 or 64 bit
1845 unsigned char endianness; // MSB or LSB
1846 char* name; // String representation
1847 } arch_t;
1848
1849 #ifndef EM_486
1850 #define EM_486 6 /* Intel 80486 */
1851 #endif
1852 #ifndef EM_AARCH64
1853 #define EM_AARCH64 183 /* ARM AARCH64 */
1854 #endif
1855
1856 static const arch_t arch_array[]={
1857 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1858 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1859 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1860 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1861 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1862 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1863 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1864 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1865 #if defined(VM_LITTLE_ENDIAN)
1866 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1867 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1868 #else
1869 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1870 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1871 #endif
1872 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1873 // we only support 64 bit z architecture
1874 {EM_S390, EM_S390, ELFCLASS64, ELFDATA2MSB, (char*)"IBM System/390"},
1875 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1876 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1877 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1878 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1879 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1880 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1881 };
1882
1883 #if (defined IA32)
1884 static Elf32_Half running_arch_code=EM_386;
1885 #elif (defined AMD64) || (defined X32)
1886 static Elf32_Half running_arch_code=EM_X86_64;
1887 #elif (defined IA64)
1888 static Elf32_Half running_arch_code=EM_IA_64;
1889 #elif (defined __sparc) && (defined _LP64)
1890 static Elf32_Half running_arch_code=EM_SPARCV9;
1891 #elif (defined __sparc) && (!defined _LP64)
1892 static Elf32_Half running_arch_code=EM_SPARC;
1893 #elif (defined __powerpc64__)
1894 static Elf32_Half running_arch_code=EM_PPC64;
1895 #elif (defined __powerpc__)
1896 static Elf32_Half running_arch_code=EM_PPC;
1897 #elif (defined AARCH64)
1898 static Elf32_Half running_arch_code=EM_AARCH64;
1899 #elif (defined ARM)
1900 static Elf32_Half running_arch_code=EM_ARM;
1901 #elif (defined S390)
1902 static Elf32_Half running_arch_code=EM_S390;
1903 #elif (defined ALPHA)
1904 static Elf32_Half running_arch_code=EM_ALPHA;
1905 #elif (defined MIPSEL)
1906 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1907 #elif (defined PARISC)
1908 static Elf32_Half running_arch_code=EM_PARISC;
1909 #elif (defined MIPS)
1910 static Elf32_Half running_arch_code=EM_MIPS;
1911 #elif (defined M68K)
1912 static Elf32_Half running_arch_code=EM_68K;
1913 #elif (defined SH)
1914 static Elf32_Half running_arch_code=EM_SH;
1915 #else
1916 #error Method os::dll_load requires that one of following is defined:\
1917 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc
1918 #endif
1919
1920 // Identify compatibility class for VM's architecture and library's architecture
1921 // Obtain string descriptions for architectures
1922
1923 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1924 int running_arch_index=-1;
1925
1926 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1927 if (running_arch_code == arch_array[i].code) {
1928 running_arch_index = i;
1929 }
1930 if (lib_arch.code == arch_array[i].code) {
1931 lib_arch.compat_class = arch_array[i].compat_class;
1932 lib_arch.name = arch_array[i].name;
1933 }
1934 }
1935
1936 assert(running_arch_index != -1,
1937 "Didn't find running architecture code (running_arch_code) in arch_array");
1938 if (running_arch_index == -1) {
1939 // Even though running architecture detection failed
1940 // we may still continue with reporting dlerror() message
1941 return NULL;
1942 }
1943
1944 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1945 if (lib_arch.name != NULL) {
1946 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1947 " (Possible cause: can't load %s .so on a %s platform)",
1948 lib_arch.name, arch_array[running_arch_index].name);
1949 } else {
1950 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1951 " (Possible cause: can't load this .so (machine code=0x%x) on a %s platform)",
1952 lib_arch.code, arch_array[running_arch_index].name);
1953 }
1954 return NULL;
1955 }
1956
1957 if (lib_arch.endianness != arch_array[running_arch_index].endianness) {
1958 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: endianness mismatch)");
1959 return NULL;
1960 }
1961
1962 // ELF file class/capacity : 0 - invalid, 1 - 32bit, 2 - 64bit
1963 if (lib_arch.elf_class > 2 || lib_arch.elf_class < 1) {
1964 ::snprintf(diag_msg_buf, diag_msg_max_length-1, " (Possible cause: invalid ELF file class)");
1965 return NULL;
1966 }
1967
1968 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1969 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1970 " (Possible cause: architecture word width mismatch, can't load %d-bit .so on a %d-bit platform)",
1971 (int) lib_arch.elf_class * 32, arch_array[running_arch_index].elf_class * 32);
1972 return NULL;
1973 }
1974
1975 return NULL;
1976 }
1977
1978 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1979 int ebuflen) {
1980 void * result = ::dlopen(filename, RTLD_LAZY);
1981 if (result == NULL) {
1982 const char* error_report = ::dlerror();
1983 if (error_report == NULL) {
1984 error_report = "dlerror returned no error description";
1985 }
1986 if (ebuf != NULL && ebuflen > 0) {
1987 ::strncpy(ebuf, error_report, ebuflen-1);
1988 ebuf[ebuflen-1]='\0';
1989 }
1990 Events::log(NULL, "Loading shared library %s failed, %s", filename, error_report);
1991 log_info(os)("shared library load of %s failed, %s", filename, error_report);
1992 } else {
1993 Events::log(NULL, "Loaded shared library %s", filename);
1994 log_info(os)("shared library load of %s was successful", filename);
1995 }
1996 return result;
1997 }
1998
1999 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
2000 int ebuflen) {
2001 void * result = NULL;
2002 if (LoadExecStackDllInVMThread) {
2003 result = dlopen_helper(filename, ebuf, ebuflen);
2004 }
2005
2006 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2007 // library that requires an executable stack, or which does not have this
2008 // stack attribute set, dlopen changes the stack attribute to executable. The
2009 // read protection of the guard pages gets lost.
2010 //
2011 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2012 // may have been queued at the same time.
2013
2014 if (!_stack_is_executable) {
2015 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2016 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2017 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
2018 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
2019 warning("Attempt to reguard stack yellow zone failed.");
2020 }
2021 }
2022 }
2023 }
2024
2025 return result;
2026 }
2027
2028 void* os::dll_lookup(void* handle, const char* name) {
2029 void* res = dlsym(handle, name);
2030 return res;
2031 }
2032
2033 void* os::get_default_process_handle() {
2034 return (void*)::dlopen(NULL, RTLD_LAZY);
2035 }
2036
2037 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
2038 int fd = ::open(filename, O_RDONLY);
2039 if (fd == -1) {
2040 return false;
2041 }
2042
2043 if (hdr != NULL) {
2044 st->print_cr("%s", hdr);
2045 }
2046
2047 char buf[33];
2048 int bytes;
2049 buf[32] = '\0';
2050 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
2051 st->print_raw(buf, bytes);
2052 }
2053
2054 ::close(fd);
2055
2056 return true;
2057 }
2058
2059 void os::print_dll_info(outputStream *st) {
2060 st->print_cr("Dynamic libraries:");
2061
2062 char fname[32];
2063 pid_t pid = os::Linux::gettid();
2064
2065 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2066
2067 if (!_print_ascii_file(fname, st)) {
2068 st->print("Can not get library information for pid = %d\n", pid);
2069 }
2070 }
2071
2072 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2073 FILE *procmapsFile = NULL;
2074
2075 // Open the procfs maps file for the current process
2076 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2077 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2078 char line[PATH_MAX + 100];
2079
2080 // Read line by line from 'file'
2081 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2082 u8 base, top, offset, inode;
2083 char permissions[5];
2084 char device[6];
2085 char name[PATH_MAX + 1];
2086
2087 // Parse fields from line
2088 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s",
2089 &base, &top, permissions, &offset, device, &inode, name);
2090
2091 // Filter by device id '00:00' so that we only get file system mapped files.
2092 if (strcmp(device, "00:00") != 0) {
2093
2094 // Call callback with the fields of interest
2095 if(callback(name, (address)base, (address)top, param)) {
2096 // Oops abort, callback aborted
2097 fclose(procmapsFile);
2098 return 1;
2099 }
2100 }
2101 }
2102 fclose(procmapsFile);
2103 }
2104 return 0;
2105 }
2106
2107 void os::print_os_info_brief(outputStream* st) {
2108 os::Linux::print_distro_info(st);
2109
2110 os::Posix::print_uname_info(st);
2111
2112 os::Linux::print_libversion_info(st);
2113
2114 }
2115
2116 void os::print_os_info(outputStream* st) {
2117 st->print("OS:");
2118
2119 os::Linux::print_distro_info(st);
2120
2121 os::Posix::print_uname_info(st);
2122
2123 // Print warning if unsafe chroot environment detected
2124 if (unsafe_chroot_detected) {
2125 st->print("WARNING!! ");
2126 st->print_cr("%s", unstable_chroot_error);
2127 }
2128
2129 os::Linux::print_libversion_info(st);
2130
2131 os::Posix::print_rlimit_info(st);
2132
2133 os::Posix::print_load_average(st);
2134
2135 os::Linux::print_full_memory_info(st);
2136
2137 os::Linux::print_proc_sys_info(st);
2138
2139 os::Linux::print_ld_preload_file(st);
2140
2141 os::Linux::print_container_info(st);
2142
2143 VM_Version::print_platform_virtualization_info(st);
2144
2145 os::Linux::print_steal_info(st);
2146 }
2147
2148 // Try to identify popular distros.
2149 // Most Linux distributions have a /etc/XXX-release file, which contains
2150 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2151 // file that also contains the OS version string. Some have more than one
2152 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2153 // /etc/redhat-release.), so the order is important.
2154 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2155 // their own specific XXX-release file as well as a redhat-release file.
2156 // Because of this the XXX-release file needs to be searched for before the
2157 // redhat-release file.
2158 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2159 // search for redhat-release / SuSE-release needs to be before lsb-release.
2160 // Since the lsb-release file is the new standard it needs to be searched
2161 // before the older style release files.
2162 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2163 // next to last resort. The os-release file is a new standard that contains
2164 // distribution information and the system-release file seems to be an old
2165 // standard that has been replaced by the lsb-release and os-release files.
2166 // Searching for the debian_version file is the last resort. It contains
2167 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2168 // "Debian " is printed before the contents of the debian_version file.
2169
2170 const char* distro_files[] = {
2171 "/etc/oracle-release",
2172 "/etc/mandriva-release",
2173 "/etc/mandrake-release",
2174 "/etc/sun-release",
2175 "/etc/redhat-release",
2176 "/etc/SuSE-release",
2177 "/etc/lsb-release",
2178 "/etc/turbolinux-release",
2179 "/etc/gentoo-release",
2180 "/etc/ltib-release",
2181 "/etc/angstrom-version",
2182 "/etc/system-release",
2183 "/etc/os-release",
2184 NULL };
2185
2186 void os::Linux::print_distro_info(outputStream* st) {
2187 for (int i = 0;; i++) {
2188 const char* file = distro_files[i];
2189 if (file == NULL) {
2190 break; // done
2191 }
2192 // If file prints, we found it.
2193 if (_print_ascii_file(file, st)) {
2194 return;
2195 }
2196 }
2197
2198 if (file_exists("/etc/debian_version")) {
2199 st->print("Debian ");
2200 _print_ascii_file("/etc/debian_version", st);
2201 } else {
2202 st->print("Linux");
2203 }
2204 st->cr();
2205 }
2206
2207 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2208 char buf[256];
2209 while (fgets(buf, sizeof(buf), fp)) {
2210 // Edit out extra stuff in expected format
2211 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2212 char* ptr = strstr(buf, "\""); // the name is in quotes
2213 if (ptr != NULL) {
2214 ptr++; // go beyond first quote
2215 char* nl = strchr(ptr, '\"');
2216 if (nl != NULL) *nl = '\0';
2217 strncpy(distro, ptr, length);
2218 } else {
2219 ptr = strstr(buf, "=");
2220 ptr++; // go beyond equals then
2221 char* nl = strchr(ptr, '\n');
2222 if (nl != NULL) *nl = '\0';
2223 strncpy(distro, ptr, length);
2224 }
2225 return;
2226 } else if (get_first_line) {
2227 char* nl = strchr(buf, '\n');
2228 if (nl != NULL) *nl = '\0';
2229 strncpy(distro, buf, length);
2230 return;
2231 }
2232 }
2233 // print last line and close
2234 char* nl = strchr(buf, '\n');
2235 if (nl != NULL) *nl = '\0';
2236 strncpy(distro, buf, length);
2237 }
2238
2239 static void parse_os_info(char* distro, size_t length, const char* file) {
2240 FILE* fp = fopen(file, "r");
2241 if (fp != NULL) {
2242 // if suse format, print out first line
2243 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2244 parse_os_info_helper(fp, distro, length, get_first_line);
2245 fclose(fp);
2246 }
2247 }
2248
2249 void os::get_summary_os_info(char* buf, size_t buflen) {
2250 for (int i = 0;; i++) {
2251 const char* file = distro_files[i];
2252 if (file == NULL) {
2253 break; // ran out of distro_files
2254 }
2255 if (file_exists(file)) {
2256 parse_os_info(buf, buflen, file);
2257 return;
2258 }
2259 }
2260 // special case for debian
2261 if (file_exists("/etc/debian_version")) {
2262 strncpy(buf, "Debian ", buflen);
2263 if (buflen > 7) {
2264 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2265 }
2266 } else {
2267 strncpy(buf, "Linux", buflen);
2268 }
2269 }
2270
2271 void os::Linux::print_libversion_info(outputStream* st) {
2272 // libc, pthread
2273 st->print("libc:");
2274 st->print("%s ", os::Linux::glibc_version());
2275 st->print("%s ", os::Linux::libpthread_version());
2276 st->cr();
2277 }
2278
2279 void os::Linux::print_proc_sys_info(outputStream* st) {
2280 st->cr();
2281 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
2282 _print_ascii_file("/proc/sys/kernel/threads-max", st);
2283 st->cr();
2284 st->cr();
2285
2286 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
2287 _print_ascii_file("/proc/sys/vm/max_map_count", st);
2288 st->cr();
2289 st->cr();
2290
2291 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
2292 _print_ascii_file("/proc/sys/kernel/pid_max", st);
2293 st->cr();
2294 st->cr();
2295 }
2296
2297 void os::Linux::print_full_memory_info(outputStream* st) {
2298 st->print("\n/proc/meminfo:\n");
2299 _print_ascii_file("/proc/meminfo", st);
2300 st->cr();
2301 }
2302
2303 void os::Linux::print_ld_preload_file(outputStream* st) {
2304 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2305 st->cr();
2306 }
2307
2308 void os::Linux::print_container_info(outputStream* st) {
2309 if (!OSContainer::is_containerized()) {
2310 return;
2311 }
2312
2313 st->print("container (cgroup) information:\n");
2314
2315 const char *p_ct = OSContainer::container_type();
2316 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2317
2318 char *p = OSContainer::cpu_cpuset_cpus();
2319 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2320 free(p);
2321
2322 p = OSContainer::cpu_cpuset_memory_nodes();
2323 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2324 free(p);
2325
2326 int i = OSContainer::active_processor_count();
2327 st->print("active_processor_count: ");
2328 if (i > 0) {
2329 st->print("%d\n", i);
2330 } else {
2331 st->print("not supported\n");
2332 }
2333
2334 i = OSContainer::cpu_quota();
2335 st->print("cpu_quota: ");
2336 if (i > 0) {
2337 st->print("%d\n", i);
2338 } else {
2339 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2340 }
2341
2342 i = OSContainer::cpu_period();
2343 st->print("cpu_period: ");
2344 if (i > 0) {
2345 st->print("%d\n", i);
2346 } else {
2347 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2348 }
2349
2350 i = OSContainer::cpu_shares();
2351 st->print("cpu_shares: ");
2352 if (i > 0) {
2353 st->print("%d\n", i);
2354 } else {
2355 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2356 }
2357
2358 jlong j = OSContainer::memory_limit_in_bytes();
2359 st->print("memory_limit_in_bytes: ");
2360 if (j > 0) {
2361 st->print(JLONG_FORMAT "\n", j);
2362 } else {
2363 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2364 }
2365
2366 j = OSContainer::memory_and_swap_limit_in_bytes();
2367 st->print("memory_and_swap_limit_in_bytes: ");
2368 if (j > 0) {
2369 st->print(JLONG_FORMAT "\n", j);
2370 } else {
2371 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2372 }
2373
2374 j = OSContainer::memory_soft_limit_in_bytes();
2375 st->print("memory_soft_limit_in_bytes: ");
2376 if (j > 0) {
2377 st->print(JLONG_FORMAT "\n", j);
2378 } else {
2379 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2380 }
2381
2382 j = OSContainer::OSContainer::memory_usage_in_bytes();
2383 st->print("memory_usage_in_bytes: ");
2384 if (j > 0) {
2385 st->print(JLONG_FORMAT "\n", j);
2386 } else {
2387 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2388 }
2389
2390 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2391 st->print("memory_max_usage_in_bytes: ");
2392 if (j > 0) {
2393 st->print(JLONG_FORMAT "\n", j);
2394 } else {
2395 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2396 }
2397 st->cr();
2398 }
2399
2400 void os::Linux::print_steal_info(outputStream* st) {
2401 if (has_initial_tick_info) {
2402 CPUPerfTicks pticks;
2403 bool res = os::Linux::get_tick_information(&pticks, -1);
2404
2405 if (res && pticks.has_steal_ticks) {
2406 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2407 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2408 double steal_ticks_perc = 0.0;
2409 if (total_ticks_difference != 0) {
2410 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2411 }
2412 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2413 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2414 }
2415 }
2416 }
2417
2418 void os::print_memory_info(outputStream* st) {
2419
2420 st->print("Memory:");
2421 st->print(" %dk page", os::vm_page_size()>>10);
2422
2423 // values in struct sysinfo are "unsigned long"
2424 struct sysinfo si;
2425 sysinfo(&si);
2426
2427 st->print(", physical " UINT64_FORMAT "k",
2428 os::physical_memory() >> 10);
2429 st->print("(" UINT64_FORMAT "k free)",
2430 os::available_memory() >> 10);
2431 st->print(", swap " UINT64_FORMAT "k",
2432 ((jlong)si.totalswap * si.mem_unit) >> 10);
2433 st->print("(" UINT64_FORMAT "k free)",
2434 ((jlong)si.freeswap * si.mem_unit) >> 10);
2435 st->cr();
2436 }
2437
2438 // Print the first "model name" line and the first "flags" line
2439 // that we find and nothing more. We assume "model name" comes
2440 // before "flags" so if we find a second "model name", then the
2441 // "flags" field is considered missing.
2442 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2443 #if defined(IA32) || defined(AMD64)
2444 // Other platforms have less repetitive cpuinfo files
2445 FILE *fp = fopen("/proc/cpuinfo", "r");
2446 if (fp) {
2447 while (!feof(fp)) {
2448 if (fgets(buf, buflen, fp)) {
2449 // Assume model name comes before flags
2450 bool model_name_printed = false;
2451 if (strstr(buf, "model name") != NULL) {
2452 if (!model_name_printed) {
2453 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2454 st->print_raw(buf);
2455 model_name_printed = true;
2456 } else {
2457 // model name printed but not flags? Odd, just return
2458 fclose(fp);
2459 return true;
2460 }
2461 }
2462 // print the flags line too
2463 if (strstr(buf, "flags") != NULL) {
2464 st->print_raw(buf);
2465 fclose(fp);
2466 return true;
2467 }
2468 }
2469 }
2470 fclose(fp);
2471 }
2472 #endif // x86 platforms
2473 return false;
2474 }
2475
2476 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2477 // Only print the model name if the platform provides this as a summary
2478 if (!print_model_name_and_flags(st, buf, buflen)) {
2479 st->print("\n/proc/cpuinfo:\n");
2480 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2481 st->print_cr(" <Not Available>");
2482 }
2483 }
2484 }
2485
2486 #if defined(AMD64) || defined(IA32) || defined(X32)
2487 const char* search_string = "model name";
2488 #elif defined(M68K)
2489 const char* search_string = "CPU";
2490 #elif defined(PPC64)
2491 const char* search_string = "cpu";
2492 #elif defined(S390)
2493 const char* search_string = "machine =";
2494 #elif defined(SPARC)
2495 const char* search_string = "cpu";
2496 #else
2497 const char* search_string = "Processor";
2498 #endif
2499
2500 // Parses the cpuinfo file for string representing the model name.
2501 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2502 FILE* fp = fopen("/proc/cpuinfo", "r");
2503 if (fp != NULL) {
2504 while (!feof(fp)) {
2505 char buf[256];
2506 if (fgets(buf, sizeof(buf), fp)) {
2507 char* start = strstr(buf, search_string);
2508 if (start != NULL) {
2509 char *ptr = start + strlen(search_string);
2510 char *end = buf + strlen(buf);
2511 while (ptr != end) {
2512 // skip whitespace and colon for the rest of the name.
2513 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2514 break;
2515 }
2516 ptr++;
2517 }
2518 if (ptr != end) {
2519 // reasonable string, get rid of newline and keep the rest
2520 char* nl = strchr(buf, '\n');
2521 if (nl != NULL) *nl = '\0';
2522 strncpy(cpuinfo, ptr, length);
2523 fclose(fp);
2524 return;
2525 }
2526 }
2527 }
2528 }
2529 fclose(fp);
2530 }
2531 // cpuinfo not found or parsing failed, just print generic string. The entire
2532 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2533 #if defined(AARCH64)
2534 strncpy(cpuinfo, "AArch64", length);
2535 #elif defined(AMD64)
2536 strncpy(cpuinfo, "x86_64", length);
2537 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2538 strncpy(cpuinfo, "ARM", length);
2539 #elif defined(IA32)
2540 strncpy(cpuinfo, "x86_32", length);
2541 #elif defined(IA64)
2542 strncpy(cpuinfo, "IA64", length);
2543 #elif defined(PPC)
2544 strncpy(cpuinfo, "PPC64", length);
2545 #elif defined(S390)
2546 strncpy(cpuinfo, "S390", length);
2547 #elif defined(SPARC)
2548 strncpy(cpuinfo, "sparcv9", length);
2549 #elif defined(ZERO_LIBARCH)
2550 strncpy(cpuinfo, ZERO_LIBARCH, length);
2551 #else
2552 strncpy(cpuinfo, "unknown", length);
2553 #endif
2554 }
2555
2556 static void print_signal_handler(outputStream* st, int sig,
2557 char* buf, size_t buflen);
2558
2559 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2560 st->print_cr("Signal Handlers:");
2561 print_signal_handler(st, SIGSEGV, buf, buflen);
2562 print_signal_handler(st, SIGBUS , buf, buflen);
2563 print_signal_handler(st, SIGFPE , buf, buflen);
2564 print_signal_handler(st, SIGPIPE, buf, buflen);
2565 print_signal_handler(st, SIGXFSZ, buf, buflen);
2566 print_signal_handler(st, SIGILL , buf, buflen);
2567 print_signal_handler(st, SR_signum, buf, buflen);
2568 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2569 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2570 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2571 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2572 #if defined(PPC64)
2573 print_signal_handler(st, SIGTRAP, buf, buflen);
2574 #endif
2575 }
2576
2577 static char saved_jvm_path[MAXPATHLEN] = {0};
2578
2579 // Find the full path to the current module, libjvm.so
2580 void os::jvm_path(char *buf, jint buflen) {
2581 // Error checking.
2582 if (buflen < MAXPATHLEN) {
2583 assert(false, "must use a large-enough buffer");
2584 buf[0] = '\0';
2585 return;
2586 }
2587 // Lazy resolve the path to current module.
2588 if (saved_jvm_path[0] != 0) {
2589 strcpy(buf, saved_jvm_path);
2590 return;
2591 }
2592
2593 char dli_fname[MAXPATHLEN];
2594 bool ret = dll_address_to_library_name(
2595 CAST_FROM_FN_PTR(address, os::jvm_path),
2596 dli_fname, sizeof(dli_fname), NULL);
2597 assert(ret, "cannot locate libjvm");
2598 char *rp = NULL;
2599 if (ret && dli_fname[0] != '\0') {
2600 rp = os::Posix::realpath(dli_fname, buf, buflen);
2601 }
2602 if (rp == NULL) {
2603 return;
2604 }
2605
2606 if (Arguments::sun_java_launcher_is_altjvm()) {
2607 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2608 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2609 // If "/jre/lib/" appears at the right place in the string, then
2610 // assume we are installed in a JDK and we're done. Otherwise, check
2611 // for a JAVA_HOME environment variable and fix up the path so it
2612 // looks like libjvm.so is installed there (append a fake suffix
2613 // hotspot/libjvm.so).
2614 const char *p = buf + strlen(buf) - 1;
2615 for (int count = 0; p > buf && count < 5; ++count) {
2616 for (--p; p > buf && *p != '/'; --p)
2617 /* empty */ ;
2618 }
2619
2620 if (strncmp(p, "/jre/lib/", 9) != 0) {
2621 // Look for JAVA_HOME in the environment.
2622 char* java_home_var = ::getenv("JAVA_HOME");
2623 if (java_home_var != NULL && java_home_var[0] != 0) {
2624 char* jrelib_p;
2625 int len;
2626
2627 // Check the current module name "libjvm.so".
2628 p = strrchr(buf, '/');
2629 if (p == NULL) {
2630 return;
2631 }
2632 assert(strstr(p, "/libjvm") == p, "invalid library name");
2633
2634 rp = os::Posix::realpath(java_home_var, buf, buflen);
2635 if (rp == NULL) {
2636 return;
2637 }
2638
2639 // determine if this is a legacy image or modules image
2640 // modules image doesn't have "jre" subdirectory
2641 len = strlen(buf);
2642 assert(len < buflen, "Ran out of buffer room");
2643 jrelib_p = buf + len;
2644 snprintf(jrelib_p, buflen-len, "/jre/lib");
2645 if (0 != access(buf, F_OK)) {
2646 snprintf(jrelib_p, buflen-len, "/lib");
2647 }
2648
2649 if (0 == access(buf, F_OK)) {
2650 // Use current module name "libjvm.so"
2651 len = strlen(buf);
2652 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2653 } else {
2654 // Go back to path of .so
2655 rp = os::Posix::realpath(dli_fname, buf, buflen);
2656 if (rp == NULL) {
2657 return;
2658 }
2659 }
2660 }
2661 }
2662 }
2663
2664 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2665 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2666 }
2667
2668 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2669 // no prefix required, not even "_"
2670 }
2671
2672 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2673 // no suffix required
2674 }
2675
2676 ////////////////////////////////////////////////////////////////////////////////
2677 // sun.misc.Signal support
2678
2679 static void UserHandler(int sig, void *siginfo, void *context) {
2680 // Ctrl-C is pressed during error reporting, likely because the error
2681 // handler fails to abort. Let VM die immediately.
2682 if (sig == SIGINT && VMError::is_error_reported()) {
2683 os::die();
2684 }
2685
2686 os::signal_notify(sig);
2687 }
2688
2689 void* os::user_handler() {
2690 return CAST_FROM_FN_PTR(void*, UserHandler);
2691 }
2692
2693 extern "C" {
2694 typedef void (*sa_handler_t)(int);
2695 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2696 }
2697
2698 void* os::signal(int signal_number, void* handler) {
2699 struct sigaction sigAct, oldSigAct;
2700
2701 sigfillset(&(sigAct.sa_mask));
2702 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2703 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2704
2705 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2706 // -1 means registration failed
2707 return (void *)-1;
2708 }
2709
2710 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2711 }
2712
2713 void os::signal_raise(int signal_number) {
2714 ::raise(signal_number);
2715 }
2716
2717 // The following code is moved from os.cpp for making this
2718 // code platform specific, which it is by its very nature.
2719
2720 // Will be modified when max signal is changed to be dynamic
2721 int os::sigexitnum_pd() {
2722 return NSIG;
2723 }
2724
2725 // a counter for each possible signal value
2726 static volatile jint pending_signals[NSIG+1] = { 0 };
2727
2728 // Linux(POSIX) specific hand shaking semaphore.
2729 static Semaphore* sig_sem = NULL;
2730 static PosixSemaphore sr_semaphore;
2731
2732 static void jdk_misc_signal_init() {
2733 // Initialize signal structures
2734 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2735
2736 // Initialize signal semaphore
2737 sig_sem = new Semaphore();
2738 }
2739
2740 void os::signal_notify(int sig) {
2741 if (sig_sem != NULL) {
2742 Atomic::inc(&pending_signals[sig]);
2743 sig_sem->signal();
2744 } else {
2745 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2746 // initialization isn't called.
2747 assert(ReduceSignalUsage, "signal semaphore should be created");
2748 }
2749 }
2750
2751 static int check_pending_signals() {
2752 for (;;) {
2753 for (int i = 0; i < NSIG + 1; i++) {
2754 jint n = pending_signals[i];
2755 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2756 return i;
2757 }
2758 }
2759 JavaThread *thread = JavaThread::current();
2760 ThreadBlockInVM tbivm(thread);
2761
2762 bool threadIsSuspended;
2763 do {
2764 thread->set_suspend_equivalent();
2765 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2766 sig_sem->wait();
2767
2768 // were we externally suspended while we were waiting?
2769 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2770 if (threadIsSuspended) {
2771 // The semaphore has been incremented, but while we were waiting
2772 // another thread suspended us. We don't want to continue running
2773 // while suspended because that would surprise the thread that
2774 // suspended us.
2775 sig_sem->signal();
2776
2777 thread->java_suspend_self();
2778 }
2779 } while (threadIsSuspended);
2780 }
2781 }
2782
2783 int os::signal_wait() {
2784 return check_pending_signals();
2785 }
2786
2787 ////////////////////////////////////////////////////////////////////////////////
2788 // Virtual Memory
2789
2790 int os::vm_page_size() {
2791 // Seems redundant as all get out
2792 assert(os::Linux::page_size() != -1, "must call os::init");
2793 return os::Linux::page_size();
2794 }
2795
2796 // Solaris allocates memory by pages.
2797 int os::vm_allocation_granularity() {
2798 assert(os::Linux::page_size() != -1, "must call os::init");
2799 return os::Linux::page_size();
2800 }
2801
2802 // Rationale behind this function:
2803 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2804 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2805 // samples for JITted code. Here we create private executable mapping over the code cache
2806 // and then we can use standard (well, almost, as mapping can change) way to provide
2807 // info for the reporting script by storing timestamp and location of symbol
2808 void linux_wrap_code(char* base, size_t size) {
2809 static volatile jint cnt = 0;
2810
2811 if (!UseOprofile) {
2812 return;
2813 }
2814
2815 char buf[PATH_MAX+1];
2816 int num = Atomic::add(1, &cnt);
2817
2818 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2819 os::get_temp_directory(), os::current_process_id(), num);
2820 unlink(buf);
2821
2822 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2823
2824 if (fd != -1) {
2825 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2826 if (rv != (off_t)-1) {
2827 if (::write(fd, "", 1) == 1) {
2828 mmap(base, size,
2829 PROT_READ|PROT_WRITE|PROT_EXEC,
2830 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2831 }
2832 }
2833 ::close(fd);
2834 unlink(buf);
2835 }
2836 }
2837
2838 static bool recoverable_mmap_error(int err) {
2839 // See if the error is one we can let the caller handle. This
2840 // list of errno values comes from JBS-6843484. I can't find a
2841 // Linux man page that documents this specific set of errno
2842 // values so while this list currently matches Solaris, it may
2843 // change as we gain experience with this failure mode.
2844 switch (err) {
2845 case EBADF:
2846 case EINVAL:
2847 case ENOTSUP:
2848 // let the caller deal with these errors
2849 return true;
2850
2851 default:
2852 // Any remaining errors on this OS can cause our reserved mapping
2853 // to be lost. That can cause confusion where different data
2854 // structures think they have the same memory mapped. The worst
2855 // scenario is if both the VM and a library think they have the
2856 // same memory mapped.
2857 return false;
2858 }
2859 }
2860
2861 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2862 int err) {
2863 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2864 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2865 os::strerror(err), err);
2866 }
2867
2868 static void warn_fail_commit_memory(char* addr, size_t size,
2869 size_t alignment_hint, bool exec,
2870 int err) {
2871 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2872 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2873 alignment_hint, exec, os::strerror(err), err);
2874 }
2875
2876 // NOTE: Linux kernel does not really reserve the pages for us.
2877 // All it does is to check if there are enough free pages
2878 // left at the time of mmap(). This could be a potential
2879 // problem.
2880 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2881 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2882 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2883 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2884 if (res != (uintptr_t) MAP_FAILED) {
2885 if (UseNUMAInterleaving) {
2886 numa_make_global(addr, size);
2887 }
2888 return 0;
2889 }
2890
2891 int err = errno; // save errno from mmap() call above
2892
2893 if (!recoverable_mmap_error(err)) {
2894 warn_fail_commit_memory(addr, size, exec, err);
2895 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2896 }
2897
2898 return err;
2899 }
2900
2901 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2902 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2903 }
2904
2905 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2906 const char* mesg) {
2907 assert(mesg != NULL, "mesg must be specified");
2908 int err = os::Linux::commit_memory_impl(addr, size, exec);
2909 if (err != 0) {
2910 // the caller wants all commit errors to exit with the specified mesg:
2911 warn_fail_commit_memory(addr, size, exec, err);
2912 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2913 }
2914 }
2915
2916 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2917 #ifndef MAP_HUGETLB
2918 #define MAP_HUGETLB 0x40000
2919 #endif
2920
2921 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2922 #ifndef MADV_HUGEPAGE
2923 #define MADV_HUGEPAGE 14
2924 #endif
2925
2926 int os::Linux::commit_memory_impl(char* addr, size_t size,
2927 size_t alignment_hint, bool exec) {
2928 int err = os::Linux::commit_memory_impl(addr, size, exec);
2929 if (err == 0) {
2930 realign_memory(addr, size, alignment_hint);
2931 }
2932 return err;
2933 }
2934
2935 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2936 bool exec) {
2937 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2938 }
2939
2940 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2941 size_t alignment_hint, bool exec,
2942 const char* mesg) {
2943 assert(mesg != NULL, "mesg must be specified");
2944 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2945 if (err != 0) {
2946 // the caller wants all commit errors to exit with the specified mesg:
2947 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2948 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2949 }
2950 }
2951
2952 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2953 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2954 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2955 // be supported or the memory may already be backed by huge pages.
2956 ::madvise(addr, bytes, MADV_HUGEPAGE);
2957 }
2958 }
2959
2960 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2961 // This method works by doing an mmap over an existing mmaping and effectively discarding
2962 // the existing pages. However it won't work for SHM-based large pages that cannot be
2963 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2964 // small pages on top of the SHM segment. This method always works for small pages, so we
2965 // allow that in any case.
2966 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2967 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2968 }
2969 }
2970
2971 void os::numa_make_global(char *addr, size_t bytes) {
2972 Linux::numa_interleave_memory(addr, bytes);
2973 }
2974
2975 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2976 // bind policy to MPOL_PREFERRED for the current thread.
2977 #define USE_MPOL_PREFERRED 0
2978
2979 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2980 // To make NUMA and large pages more robust when both enabled, we need to ease
2981 // the requirements on where the memory should be allocated. MPOL_BIND is the
2982 // default policy and it will force memory to be allocated on the specified
2983 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2984 // the specified node, but will not force it. Using this policy will prevent
2985 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2986 // free large pages.
2987 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2988 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2989 }
2990
2991 bool os::numa_topology_changed() { return false; }
2992
2993 size_t os::numa_get_groups_num() {
2994 // Return just the number of nodes in which it's possible to allocate memory
2995 // (in numa terminology, configured nodes).
2996 return Linux::numa_num_configured_nodes();
2997 }
2998
2999 int os::numa_get_group_id() {
3000 int cpu_id = Linux::sched_getcpu();
3001 if (cpu_id != -1) {
3002 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
3003 if (lgrp_id != -1) {
3004 return lgrp_id;
3005 }
3006 }
3007 return 0;
3008 }
3009
3010 int os::numa_get_group_id_for_address(const void* address) {
3011 void** pages = const_cast<void**>(&address);
3012 int id = -1;
3013
3014 if (os::Linux::numa_move_pages(0, 1, pages, NULL, &id, 0) == -1) {
3015 return -1;
3016 }
3017 if (id < 0) {
3018 return -1;
3019 }
3020 return id;
3021 }
3022
3023 int os::Linux::get_existing_num_nodes() {
3024 int node;
3025 int highest_node_number = Linux::numa_max_node();
3026 int num_nodes = 0;
3027
3028 // Get the total number of nodes in the system including nodes without memory.
3029 for (node = 0; node <= highest_node_number; node++) {
3030 if (is_node_in_existing_nodes(node)) {
3031 num_nodes++;
3032 }
3033 }
3034 return num_nodes;
3035 }
3036
3037 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
3038 int highest_node_number = Linux::numa_max_node();
3039 size_t i = 0;
3040
3041 // Map all node ids in which it is possible to allocate memory. Also nodes are
3042 // not always consecutively available, i.e. available from 0 to the highest
3043 // node number. If the nodes have been bound explicitly using numactl membind,
3044 // then allocate memory from those nodes only.
3045 for (int node = 0; node <= highest_node_number; node++) {
3046 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
3047 ids[i++] = node;
3048 }
3049 }
3050 return i;
3051 }
3052
3053 bool os::get_page_info(char *start, page_info* info) {
3054 return false;
3055 }
3056
3057 char *os::scan_pages(char *start, char* end, page_info* page_expected,
3058 page_info* page_found) {
3059 return end;
3060 }
3061
3062
3063 int os::Linux::sched_getcpu_syscall(void) {
3064 unsigned int cpu = 0;
3065 int retval = -1;
3066
3067 #if defined(IA32)
3068 #ifndef SYS_getcpu
3069 #define SYS_getcpu 318
3070 #endif
3071 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
3072 #elif defined(AMD64)
3073 // Unfortunately we have to bring all these macros here from vsyscall.h
3074 // to be able to compile on old linuxes.
3075 #define __NR_vgetcpu 2
3076 #define VSYSCALL_START (-10UL << 20)
3077 #define VSYSCALL_SIZE 1024
3078 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
3079 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
3080 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
3081 retval = vgetcpu(&cpu, NULL, NULL);
3082 #endif
3083
3084 return (retval == -1) ? retval : cpu;
3085 }
3086
3087 void os::Linux::sched_getcpu_init() {
3088 // sched_getcpu() should be in libc.
3089 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3090 dlsym(RTLD_DEFAULT, "sched_getcpu")));
3091
3092 // If it's not, try a direct syscall.
3093 if (sched_getcpu() == -1) {
3094 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
3095 (void*)&sched_getcpu_syscall));
3096 }
3097
3098 if (sched_getcpu() == -1) {
3099 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
3100 }
3101 }
3102
3103 // Something to do with the numa-aware allocator needs these symbols
3104 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
3105 extern "C" JNIEXPORT void numa_error(char *where) { }
3106
3107 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
3108 // load symbol from base version instead.
3109 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
3110 void *f = dlvsym(handle, name, "libnuma_1.1");
3111 if (f == NULL) {
3112 f = dlsym(handle, name);
3113 }
3114 return f;
3115 }
3116
3117 // Handle request to load libnuma symbol version 1.2 (API v2) only.
3118 // Return NULL if the symbol is not defined in this particular version.
3119 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3120 return dlvsym(handle, name, "libnuma_1.2");
3121 }
3122
3123 bool os::Linux::libnuma_init() {
3124 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3125 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3126 if (handle != NULL) {
3127 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3128 libnuma_dlsym(handle, "numa_node_to_cpus")));
3129 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3130 libnuma_dlsym(handle, "numa_max_node")));
3131 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3132 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3133 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3134 libnuma_dlsym(handle, "numa_available")));
3135 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3136 libnuma_dlsym(handle, "numa_tonode_memory")));
3137 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3138 libnuma_dlsym(handle, "numa_interleave_memory")));
3139 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3140 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3141 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3142 libnuma_dlsym(handle, "numa_set_bind_policy")));
3143 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3144 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3145 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3146 libnuma_dlsym(handle, "numa_distance")));
3147 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3148 libnuma_v2_dlsym(handle, "numa_get_membind")));
3149 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3150 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3151 set_numa_move_pages(CAST_TO_FN_PTR(numa_move_pages_func_t,
3152 libnuma_dlsym(handle, "numa_move_pages")));
3153
3154 if (numa_available() != -1) {
3155 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3156 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3157 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3158 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3159 set_numa_membind_bitmask(_numa_get_membind());
3160 // Create an index -> node mapping, since nodes are not always consecutive
3161 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3162 rebuild_nindex_to_node_map();
3163 // Create a cpu -> node mapping
3164 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3165 rebuild_cpu_to_node_map();
3166 return true;
3167 }
3168 }
3169 }
3170 return false;
3171 }
3172
3173 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3174 // Creating guard page is very expensive. Java thread has HotSpot
3175 // guard pages, only enable glibc guard page for non-Java threads.
3176 // (Remember: compiler thread is a Java thread, too!)
3177 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3178 }
3179
3180 void os::Linux::rebuild_nindex_to_node_map() {
3181 int highest_node_number = Linux::numa_max_node();
3182
3183 nindex_to_node()->clear();
3184 for (int node = 0; node <= highest_node_number; node++) {
3185 if (Linux::is_node_in_existing_nodes(node)) {
3186 nindex_to_node()->append(node);
3187 }
3188 }
3189 }
3190
3191 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3192 // The table is later used in get_node_by_cpu().
3193 void os::Linux::rebuild_cpu_to_node_map() {
3194 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3195 // in libnuma (possible values are starting from 16,
3196 // and continuing up with every other power of 2, but less
3197 // than the maximum number of CPUs supported by kernel), and
3198 // is a subject to change (in libnuma version 2 the requirements
3199 // are more reasonable) we'll just hardcode the number they use
3200 // in the library.
3201 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3202
3203 size_t cpu_num = processor_count();
3204 size_t cpu_map_size = NCPUS / BitsPerCLong;
3205 size_t cpu_map_valid_size =
3206 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3207
3208 cpu_to_node()->clear();
3209 cpu_to_node()->at_grow(cpu_num - 1);
3210
3211 size_t node_num = get_existing_num_nodes();
3212
3213 int distance = 0;
3214 int closest_distance = INT_MAX;
3215 int closest_node = 0;
3216 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3217 for (size_t i = 0; i < node_num; i++) {
3218 // Check if node is configured (not a memory-less node). If it is not, find
3219 // the closest configured node. Check also if node is bound, i.e. it's allowed
3220 // to allocate memory from the node. If it's not allowed, map cpus in that node
3221 // to the closest node from which memory allocation is allowed.
3222 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3223 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3224 closest_distance = INT_MAX;
3225 // Check distance from all remaining nodes in the system. Ignore distance
3226 // from itself, from another non-configured node, and from another non-bound
3227 // node.
3228 for (size_t m = 0; m < node_num; m++) {
3229 if (m != i &&
3230 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3231 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3232 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3233 // If a closest node is found, update. There is always at least one
3234 // configured and bound node in the system so there is always at least
3235 // one node close.
3236 if (distance != 0 && distance < closest_distance) {
3237 closest_distance = distance;
3238 closest_node = nindex_to_node()->at(m);
3239 }
3240 }
3241 }
3242 } else {
3243 // Current node is already a configured node.
3244 closest_node = nindex_to_node()->at(i);
3245 }
3246
3247 // Get cpus from the original node and map them to the closest node. If node
3248 // is a configured node (not a memory-less node), then original node and
3249 // closest node are the same.
3250 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3251 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3252 if (cpu_map[j] != 0) {
3253 for (size_t k = 0; k < BitsPerCLong; k++) {
3254 if (cpu_map[j] & (1UL << k)) {
3255 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3256 }
3257 }
3258 }
3259 }
3260 }
3261 }
3262 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3263 }
3264
3265 int os::Linux::get_node_by_cpu(int cpu_id) {
3266 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3267 return cpu_to_node()->at(cpu_id);
3268 }
3269 return -1;
3270 }
3271
3272 GrowableArray<int>* os::Linux::_cpu_to_node;
3273 GrowableArray<int>* os::Linux::_nindex_to_node;
3274 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3275 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3276 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3277 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3278 os::Linux::numa_available_func_t os::Linux::_numa_available;
3279 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3280 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3281 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3282 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3283 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3284 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3285 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3286 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3287 os::Linux::numa_move_pages_func_t os::Linux::_numa_move_pages;
3288 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3289 unsigned long* os::Linux::_numa_all_nodes;
3290 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3291 struct bitmask* os::Linux::_numa_nodes_ptr;
3292 struct bitmask* os::Linux::_numa_interleave_bitmask;
3293 struct bitmask* os::Linux::_numa_membind_bitmask;
3294
3295 bool os::pd_uncommit_memory(char* addr, size_t size) {
3296 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3297 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3298 return res != (uintptr_t) MAP_FAILED;
3299 }
3300
3301 static address get_stack_commited_bottom(address bottom, size_t size) {
3302 address nbot = bottom;
3303 address ntop = bottom + size;
3304
3305 size_t page_sz = os::vm_page_size();
3306 unsigned pages = size / page_sz;
3307
3308 unsigned char vec[1];
3309 unsigned imin = 1, imax = pages + 1, imid;
3310 int mincore_return_value = 0;
3311
3312 assert(imin <= imax, "Unexpected page size");
3313
3314 while (imin < imax) {
3315 imid = (imax + imin) / 2;
3316 nbot = ntop - (imid * page_sz);
3317
3318 // Use a trick with mincore to check whether the page is mapped or not.
3319 // mincore sets vec to 1 if page resides in memory and to 0 if page
3320 // is swapped output but if page we are asking for is unmapped
3321 // it returns -1,ENOMEM
3322 mincore_return_value = mincore(nbot, page_sz, vec);
3323
3324 if (mincore_return_value == -1) {
3325 // Page is not mapped go up
3326 // to find first mapped page
3327 if (errno != EAGAIN) {
3328 assert(errno == ENOMEM, "Unexpected mincore errno");
3329 imax = imid;
3330 }
3331 } else {
3332 // Page is mapped go down
3333 // to find first not mapped page
3334 imin = imid + 1;
3335 }
3336 }
3337
3338 nbot = nbot + page_sz;
3339
3340 // Adjust stack bottom one page up if last checked page is not mapped
3341 if (mincore_return_value == -1) {
3342 nbot = nbot + page_sz;
3343 }
3344
3345 return nbot;
3346 }
3347
3348 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3349 int mincore_return_value;
3350 const size_t stripe = 1024; // query this many pages each time
3351 unsigned char vec[stripe + 1];
3352 // set a guard
3353 vec[stripe] = 'X';
3354
3355 const size_t page_sz = os::vm_page_size();
3356 size_t pages = size / page_sz;
3357
3358 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3359 assert(is_aligned(size, page_sz), "Size must be page aligned");
3360
3361 committed_start = NULL;
3362
3363 int loops = (pages + stripe - 1) / stripe;
3364 int committed_pages = 0;
3365 address loop_base = start;
3366 bool found_range = false;
3367
3368 for (int index = 0; index < loops && !found_range; index ++) {
3369 assert(pages > 0, "Nothing to do");
3370 int pages_to_query = (pages >= stripe) ? stripe : pages;
3371 pages -= pages_to_query;
3372
3373 // Get stable read
3374 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3375
3376 // During shutdown, some memory goes away without properly notifying NMT,
3377 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3378 // Bailout and return as not committed for now.
3379 if (mincore_return_value == -1 && errno == ENOMEM) {
3380 return false;
3381 }
3382
3383 assert(vec[stripe] == 'X', "overflow guard");
3384 assert(mincore_return_value == 0, "Range must be valid");
3385 // Process this stripe
3386 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3387 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3388 // End of current contiguous region
3389 if (committed_start != NULL) {
3390 found_range = true;
3391 break;
3392 }
3393 } else { // committed
3394 // Start of region
3395 if (committed_start == NULL) {
3396 committed_start = loop_base + page_sz * vecIdx;
3397 }
3398 committed_pages ++;
3399 }
3400 }
3401
3402 loop_base += pages_to_query * page_sz;
3403 }
3404
3405 if (committed_start != NULL) {
3406 assert(committed_pages > 0, "Must have committed region");
3407 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3408 assert(committed_start >= start && committed_start < start + size, "Out of range");
3409 committed_size = page_sz * committed_pages;
3410 return true;
3411 } else {
3412 assert(committed_pages == 0, "Should not have committed region");
3413 return false;
3414 }
3415 }
3416
3417
3418 // Linux uses a growable mapping for the stack, and if the mapping for
3419 // the stack guard pages is not removed when we detach a thread the
3420 // stack cannot grow beyond the pages where the stack guard was
3421 // mapped. If at some point later in the process the stack expands to
3422 // that point, the Linux kernel cannot expand the stack any further
3423 // because the guard pages are in the way, and a segfault occurs.
3424 //
3425 // However, it's essential not to split the stack region by unmapping
3426 // a region (leaving a hole) that's already part of the stack mapping,
3427 // so if the stack mapping has already grown beyond the guard pages at
3428 // the time we create them, we have to truncate the stack mapping.
3429 // So, we need to know the extent of the stack mapping when
3430 // create_stack_guard_pages() is called.
3431
3432 // We only need this for stacks that are growable: at the time of
3433 // writing thread stacks don't use growable mappings (i.e. those
3434 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3435 // only applies to the main thread.
3436
3437 // If the (growable) stack mapping already extends beyond the point
3438 // where we're going to put our guard pages, truncate the mapping at
3439 // that point by munmap()ping it. This ensures that when we later
3440 // munmap() the guard pages we don't leave a hole in the stack
3441 // mapping. This only affects the main/primordial thread
3442
3443 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3444 if (os::is_primordial_thread()) {
3445 // As we manually grow stack up to bottom inside create_attached_thread(),
3446 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3447 // we don't need to do anything special.
3448 // Check it first, before calling heavy function.
3449 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3450 unsigned char vec[1];
3451
3452 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3453 // Fallback to slow path on all errors, including EAGAIN
3454 stack_extent = (uintptr_t) get_stack_commited_bottom(
3455 os::Linux::initial_thread_stack_bottom(),
3456 (size_t)addr - stack_extent);
3457 }
3458
3459 if (stack_extent < (uintptr_t)addr) {
3460 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3461 }
3462 }
3463
3464 return os::commit_memory(addr, size, !ExecMem);
3465 }
3466
3467 // If this is a growable mapping, remove the guard pages entirely by
3468 // munmap()ping them. If not, just call uncommit_memory(). This only
3469 // affects the main/primordial thread, but guard against future OS changes.
3470 // It's safe to always unmap guard pages for primordial thread because we
3471 // always place it right after end of the mapped region.
3472
3473 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3474 uintptr_t stack_extent, stack_base;
3475
3476 if (os::is_primordial_thread()) {
3477 return ::munmap(addr, size) == 0;
3478 }
3479
3480 return os::uncommit_memory(addr, size);
3481 }
3482
3483 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3484 // at 'requested_addr'. If there are existing memory mappings at the same
3485 // location, however, they will be overwritten. If 'fixed' is false,
3486 // 'requested_addr' is only treated as a hint, the return value may or
3487 // may not start from the requested address. Unlike Linux mmap(), this
3488 // function returns NULL to indicate failure.
3489 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3490 char * addr;
3491 int flags;
3492
3493 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3494 if (fixed) {
3495 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3496 flags |= MAP_FIXED;
3497 }
3498
3499 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3500 // touch an uncommitted page. Otherwise, the read/write might
3501 // succeed if we have enough swap space to back the physical page.
3502 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3503 flags, -1, 0);
3504
3505 return addr == MAP_FAILED ? NULL : addr;
3506 }
3507
3508 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3509 // (req_addr != NULL) or with a given alignment.
3510 // - bytes shall be a multiple of alignment.
3511 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3512 // - alignment sets the alignment at which memory shall be allocated.
3513 // It must be a multiple of allocation granularity.
3514 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3515 // req_addr or NULL.
3516 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3517
3518 size_t extra_size = bytes;
3519 if (req_addr == NULL && alignment > 0) {
3520 extra_size += alignment;
3521 }
3522
3523 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3524 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3525 -1, 0);
3526 if (start == MAP_FAILED) {
3527 start = NULL;
3528 } else {
3529 if (req_addr != NULL) {
3530 if (start != req_addr) {
3531 ::munmap(start, extra_size);
3532 start = NULL;
3533 }
3534 } else {
3535 char* const start_aligned = align_up(start, alignment);
3536 char* const end_aligned = start_aligned + bytes;
3537 char* const end = start + extra_size;
3538 if (start_aligned > start) {
3539 ::munmap(start, start_aligned - start);
3540 }
3541 if (end_aligned < end) {
3542 ::munmap(end_aligned, end - end_aligned);
3543 }
3544 start = start_aligned;
3545 }
3546 }
3547 return start;
3548 }
3549
3550 static int anon_munmap(char * addr, size_t size) {
3551 return ::munmap(addr, size) == 0;
3552 }
3553
3554 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3555 size_t alignment_hint) {
3556 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3557 }
3558
3559 bool os::pd_release_memory(char* addr, size_t size) {
3560 return anon_munmap(addr, size);
3561 }
3562
3563 static bool linux_mprotect(char* addr, size_t size, int prot) {
3564 // Linux wants the mprotect address argument to be page aligned.
3565 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3566
3567 // According to SUSv3, mprotect() should only be used with mappings
3568 // established by mmap(), and mmap() always maps whole pages. Unaligned
3569 // 'addr' likely indicates problem in the VM (e.g. trying to change
3570 // protection of malloc'ed or statically allocated memory). Check the
3571 // caller if you hit this assert.
3572 assert(addr == bottom, "sanity check");
3573
3574 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3575 Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(bottom), p2i(bottom+size), prot);
3576 return ::mprotect(bottom, size, prot) == 0;
3577 }
3578
3579 // Set protections specified
3580 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3581 bool is_committed) {
3582 unsigned int p = 0;
3583 switch (prot) {
3584 case MEM_PROT_NONE: p = PROT_NONE; break;
3585 case MEM_PROT_READ: p = PROT_READ; break;
3586 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3587 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3588 default:
3589 ShouldNotReachHere();
3590 }
3591 // is_committed is unused.
3592 return linux_mprotect(addr, bytes, p);
3593 }
3594
3595 bool os::guard_memory(char* addr, size_t size) {
3596 return linux_mprotect(addr, size, PROT_NONE);
3597 }
3598
3599 bool os::unguard_memory(char* addr, size_t size) {
3600 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3601 }
3602
3603 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3604 size_t page_size) {
3605 bool result = false;
3606 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3607 MAP_ANONYMOUS|MAP_PRIVATE,
3608 -1, 0);
3609 if (p != MAP_FAILED) {
3610 void *aligned_p = align_up(p, page_size);
3611
3612 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3613
3614 munmap(p, page_size * 2);
3615 }
3616
3617 if (warn && !result) {
3618 warning("TransparentHugePages is not supported by the operating system.");
3619 }
3620
3621 return result;
3622 }
3623
3624 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3625 bool result = false;
3626 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3627 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3628 -1, 0);
3629
3630 if (p != MAP_FAILED) {
3631 // We don't know if this really is a huge page or not.
3632 FILE *fp = fopen("/proc/self/maps", "r");
3633 if (fp) {
3634 while (!feof(fp)) {
3635 char chars[257];
3636 long x = 0;
3637 if (fgets(chars, sizeof(chars), fp)) {
3638 if (sscanf(chars, "%lx-%*x", &x) == 1
3639 && x == (long)p) {
3640 if (strstr (chars, "hugepage")) {
3641 result = true;
3642 break;
3643 }
3644 }
3645 }
3646 }
3647 fclose(fp);
3648 }
3649 munmap(p, page_size);
3650 }
3651
3652 if (warn && !result) {
3653 warning("HugeTLBFS is not supported by the operating system.");
3654 }
3655
3656 return result;
3657 }
3658
3659 // From the coredump_filter documentation:
3660 //
3661 // - (bit 0) anonymous private memory
3662 // - (bit 1) anonymous shared memory
3663 // - (bit 2) file-backed private memory
3664 // - (bit 3) file-backed shared memory
3665 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3666 // effective only if the bit 2 is cleared)
3667 // - (bit 5) hugetlb private memory
3668 // - (bit 6) hugetlb shared memory
3669 // - (bit 7) dax private memory
3670 // - (bit 8) dax shared memory
3671 //
3672 static void set_coredump_filter(CoredumpFilterBit bit) {
3673 FILE *f;
3674 long cdm;
3675
3676 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3677 return;
3678 }
3679
3680 if (fscanf(f, "%lx", &cdm) != 1) {
3681 fclose(f);
3682 return;
3683 }
3684
3685 long saved_cdm = cdm;
3686 rewind(f);
3687 cdm |= bit;
3688
3689 if (cdm != saved_cdm) {
3690 fprintf(f, "%#lx", cdm);
3691 }
3692
3693 fclose(f);
3694 }
3695
3696 // Large page support
3697
3698 static size_t _large_page_size = 0;
3699
3700 size_t os::Linux::find_large_page_size() {
3701 size_t large_page_size = 0;
3702
3703 // large_page_size on Linux is used to round up heap size. x86 uses either
3704 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3705 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3706 // page as large as 256M.
3707 //
3708 // Here we try to figure out page size by parsing /proc/meminfo and looking
3709 // for a line with the following format:
3710 // Hugepagesize: 2048 kB
3711 //
3712 // If we can't determine the value (e.g. /proc is not mounted, or the text
3713 // format has been changed), we'll use the largest page size supported by
3714 // the processor.
3715
3716 #ifndef ZERO
3717 large_page_size =
3718 AARCH64_ONLY(2 * M)
3719 AMD64_ONLY(2 * M)
3720 ARM32_ONLY(2 * M)
3721 IA32_ONLY(4 * M)
3722 IA64_ONLY(256 * M)
3723 PPC_ONLY(4 * M)
3724 S390_ONLY(1 * M)
3725 SPARC_ONLY(4 * M);
3726 #endif // ZERO
3727
3728 FILE *fp = fopen("/proc/meminfo", "r");
3729 if (fp) {
3730 while (!feof(fp)) {
3731 int x = 0;
3732 char buf[16];
3733 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3734 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3735 large_page_size = x * K;
3736 break;
3737 }
3738 } else {
3739 // skip to next line
3740 for (;;) {
3741 int ch = fgetc(fp);
3742 if (ch == EOF || ch == (int)'\n') break;
3743 }
3744 }
3745 }
3746 fclose(fp);
3747 }
3748
3749 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3750 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3751 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3752 proper_unit_for_byte_size(large_page_size));
3753 }
3754
3755 return large_page_size;
3756 }
3757
3758 size_t os::Linux::setup_large_page_size() {
3759 _large_page_size = Linux::find_large_page_size();
3760 const size_t default_page_size = (size_t)Linux::page_size();
3761 if (_large_page_size > default_page_size) {
3762 _page_sizes[0] = _large_page_size;
3763 _page_sizes[1] = default_page_size;
3764 _page_sizes[2] = 0;
3765 }
3766
3767 return _large_page_size;
3768 }
3769
3770 bool os::Linux::setup_large_page_type(size_t page_size) {
3771 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3772 FLAG_IS_DEFAULT(UseSHM) &&
3773 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3774
3775 // The type of large pages has not been specified by the user.
3776
3777 // Try UseHugeTLBFS and then UseSHM.
3778 UseHugeTLBFS = UseSHM = true;
3779
3780 // Don't try UseTransparentHugePages since there are known
3781 // performance issues with it turned on. This might change in the future.
3782 UseTransparentHugePages = false;
3783 }
3784
3785 if (UseTransparentHugePages) {
3786 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3787 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3788 UseHugeTLBFS = false;
3789 UseSHM = false;
3790 return true;
3791 }
3792 UseTransparentHugePages = false;
3793 }
3794
3795 if (UseHugeTLBFS) {
3796 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3797 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3798 UseSHM = false;
3799 return true;
3800 }
3801 UseHugeTLBFS = false;
3802 }
3803
3804 return UseSHM;
3805 }
3806
3807 void os::large_page_init() {
3808 if (!UseLargePages &&
3809 !UseTransparentHugePages &&
3810 !UseHugeTLBFS &&
3811 !UseSHM) {
3812 // Not using large pages.
3813 return;
3814 }
3815
3816 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3817 // The user explicitly turned off large pages.
3818 // Ignore the rest of the large pages flags.
3819 UseTransparentHugePages = false;
3820 UseHugeTLBFS = false;
3821 UseSHM = false;
3822 return;
3823 }
3824
3825 size_t large_page_size = Linux::setup_large_page_size();
3826 UseLargePages = Linux::setup_large_page_type(large_page_size);
3827
3828 set_coredump_filter(LARGEPAGES_BIT);
3829 }
3830
3831 #ifndef SHM_HUGETLB
3832 #define SHM_HUGETLB 04000
3833 #endif
3834
3835 #define shm_warning_format(format, ...) \
3836 do { \
3837 if (UseLargePages && \
3838 (!FLAG_IS_DEFAULT(UseLargePages) || \
3839 !FLAG_IS_DEFAULT(UseSHM) || \
3840 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3841 warning(format, __VA_ARGS__); \
3842 } \
3843 } while (0)
3844
3845 #define shm_warning(str) shm_warning_format("%s", str)
3846
3847 #define shm_warning_with_errno(str) \
3848 do { \
3849 int err = errno; \
3850 shm_warning_format(str " (error = %d)", err); \
3851 } while (0)
3852
3853 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3854 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3855
3856 if (!is_aligned(alignment, SHMLBA)) {
3857 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3858 return NULL;
3859 }
3860
3861 // To ensure that we get 'alignment' aligned memory from shmat,
3862 // we pre-reserve aligned virtual memory and then attach to that.
3863
3864 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3865 if (pre_reserved_addr == NULL) {
3866 // Couldn't pre-reserve aligned memory.
3867 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3868 return NULL;
3869 }
3870
3871 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3872 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3873
3874 if ((intptr_t)addr == -1) {
3875 int err = errno;
3876 shm_warning_with_errno("Failed to attach shared memory.");
3877
3878 assert(err != EACCES, "Unexpected error");
3879 assert(err != EIDRM, "Unexpected error");
3880 assert(err != EINVAL, "Unexpected error");
3881
3882 // Since we don't know if the kernel unmapped the pre-reserved memory area
3883 // we can't unmap it, since that would potentially unmap memory that was
3884 // mapped from other threads.
3885 return NULL;
3886 }
3887
3888 return addr;
3889 }
3890
3891 static char* shmat_at_address(int shmid, char* req_addr) {
3892 if (!is_aligned(req_addr, SHMLBA)) {
3893 assert(false, "Requested address needs to be SHMLBA aligned");
3894 return NULL;
3895 }
3896
3897 char* addr = (char*)shmat(shmid, req_addr, 0);
3898
3899 if ((intptr_t)addr == -1) {
3900 shm_warning_with_errno("Failed to attach shared memory.");
3901 return NULL;
3902 }
3903
3904 return addr;
3905 }
3906
3907 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3908 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3909 if (req_addr != NULL) {
3910 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3911 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3912 return shmat_at_address(shmid, req_addr);
3913 }
3914
3915 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3916 // return large page size aligned memory addresses when req_addr == NULL.
3917 // However, if the alignment is larger than the large page size, we have
3918 // to manually ensure that the memory returned is 'alignment' aligned.
3919 if (alignment > os::large_page_size()) {
3920 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3921 return shmat_with_alignment(shmid, bytes, alignment);
3922 } else {
3923 return shmat_at_address(shmid, NULL);
3924 }
3925 }
3926
3927 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3928 char* req_addr, bool exec) {
3929 // "exec" is passed in but not used. Creating the shared image for
3930 // the code cache doesn't have an SHM_X executable permission to check.
3931 assert(UseLargePages && UseSHM, "only for SHM large pages");
3932 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3933 assert(is_aligned(req_addr, alignment), "Unaligned address");
3934
3935 if (!is_aligned(bytes, os::large_page_size())) {
3936 return NULL; // Fallback to small pages.
3937 }
3938
3939 // Create a large shared memory region to attach to based on size.
3940 // Currently, size is the total size of the heap.
3941 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3942 if (shmid == -1) {
3943 // Possible reasons for shmget failure:
3944 // 1. shmmax is too small for Java heap.
3945 // > check shmmax value: cat /proc/sys/kernel/shmmax
3946 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3947 // 2. not enough large page memory.
3948 // > check available large pages: cat /proc/meminfo
3949 // > increase amount of large pages:
3950 // echo new_value > /proc/sys/vm/nr_hugepages
3951 // Note 1: different Linux may use different name for this property,
3952 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3953 // Note 2: it's possible there's enough physical memory available but
3954 // they are so fragmented after a long run that they can't
3955 // coalesce into large pages. Try to reserve large pages when
3956 // the system is still "fresh".
3957 shm_warning_with_errno("Failed to reserve shared memory.");
3958 return NULL;
3959 }
3960
3961 // Attach to the region.
3962 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3963
3964 // Remove shmid. If shmat() is successful, the actual shared memory segment
3965 // will be deleted when it's detached by shmdt() or when the process
3966 // terminates. If shmat() is not successful this will remove the shared
3967 // segment immediately.
3968 shmctl(shmid, IPC_RMID, NULL);
3969
3970 return addr;
3971 }
3972
3973 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3974 int error) {
3975 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3976
3977 bool warn_on_failure = UseLargePages &&
3978 (!FLAG_IS_DEFAULT(UseLargePages) ||
3979 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3980 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3981
3982 if (warn_on_failure) {
3983 char msg[128];
3984 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3985 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3986 warning("%s", msg);
3987 }
3988 }
3989
3990 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3991 char* req_addr,
3992 bool exec) {
3993 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3994 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
3995 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3996
3997 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3998 char* addr = (char*)::mmap(req_addr, bytes, prot,
3999 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
4000 -1, 0);
4001
4002 if (addr == MAP_FAILED) {
4003 warn_on_large_pages_failure(req_addr, bytes, errno);
4004 return NULL;
4005 }
4006
4007 assert(is_aligned(addr, os::large_page_size()), "Must be");
4008
4009 return addr;
4010 }
4011
4012 // Reserve memory using mmap(MAP_HUGETLB).
4013 // - bytes shall be a multiple of alignment.
4014 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
4015 // - alignment sets the alignment at which memory shall be allocated.
4016 // It must be a multiple of allocation granularity.
4017 // Returns address of memory or NULL. If req_addr was not NULL, will only return
4018 // req_addr or NULL.
4019 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
4020 size_t alignment,
4021 char* req_addr,
4022 bool exec) {
4023 size_t large_page_size = os::large_page_size();
4024 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
4025
4026 assert(is_aligned(req_addr, alignment), "Must be");
4027 assert(is_aligned(bytes, alignment), "Must be");
4028
4029 // First reserve - but not commit - the address range in small pages.
4030 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
4031
4032 if (start == NULL) {
4033 return NULL;
4034 }
4035
4036 assert(is_aligned(start, alignment), "Must be");
4037
4038 char* end = start + bytes;
4039
4040 // Find the regions of the allocated chunk that can be promoted to large pages.
4041 char* lp_start = align_up(start, large_page_size);
4042 char* lp_end = align_down(end, large_page_size);
4043
4044 size_t lp_bytes = lp_end - lp_start;
4045
4046 assert(is_aligned(lp_bytes, large_page_size), "Must be");
4047
4048 if (lp_bytes == 0) {
4049 // The mapped region doesn't even span the start and the end of a large page.
4050 // Fall back to allocate a non-special area.
4051 ::munmap(start, end - start);
4052 return NULL;
4053 }
4054
4055 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
4056
4057 void* result;
4058
4059 // Commit small-paged leading area.
4060 if (start != lp_start) {
4061 result = ::mmap(start, lp_start - start, prot,
4062 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4063 -1, 0);
4064 if (result == MAP_FAILED) {
4065 ::munmap(lp_start, end - lp_start);
4066 return NULL;
4067 }
4068 }
4069
4070 // Commit large-paged area.
4071 result = ::mmap(lp_start, lp_bytes, prot,
4072 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
4073 -1, 0);
4074 if (result == MAP_FAILED) {
4075 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
4076 // If the mmap above fails, the large pages region will be unmapped and we
4077 // have regions before and after with small pages. Release these regions.
4078 //
4079 // | mapped | unmapped | mapped |
4080 // ^ ^ ^ ^
4081 // start lp_start lp_end end
4082 //
4083 ::munmap(start, lp_start - start);
4084 ::munmap(lp_end, end - lp_end);
4085 return NULL;
4086 }
4087
4088 // Commit small-paged trailing area.
4089 if (lp_end != end) {
4090 result = ::mmap(lp_end, end - lp_end, prot,
4091 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
4092 -1, 0);
4093 if (result == MAP_FAILED) {
4094 ::munmap(start, lp_end - start);
4095 return NULL;
4096 }
4097 }
4098
4099 return start;
4100 }
4101
4102 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
4103 size_t alignment,
4104 char* req_addr,
4105 bool exec) {
4106 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
4107 assert(is_aligned(req_addr, alignment), "Must be");
4108 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
4109 assert(is_power_of_2(os::large_page_size()), "Must be");
4110 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
4111
4112 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
4113 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
4114 } else {
4115 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
4116 }
4117 }
4118
4119 char* os::reserve_memory_special(size_t bytes, size_t alignment,
4120 char* req_addr, bool exec) {
4121 assert(UseLargePages, "only for large pages");
4122
4123 char* addr;
4124 if (UseSHM) {
4125 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4126 } else {
4127 assert(UseHugeTLBFS, "must be");
4128 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4129 }
4130
4131 if (addr != NULL) {
4132 if (UseNUMAInterleaving) {
4133 numa_make_global(addr, bytes);
4134 }
4135
4136 // The memory is committed
4137 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
4138 }
4139
4140 return addr;
4141 }
4142
4143 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4144 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4145 return shmdt(base) == 0;
4146 }
4147
4148 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4149 return pd_release_memory(base, bytes);
4150 }
4151
4152 bool os::release_memory_special(char* base, size_t bytes) {
4153 bool res;
4154 if (MemTracker::tracking_level() > NMT_minimal) {
4155 Tracker tkr(Tracker::release);
4156 res = os::Linux::release_memory_special_impl(base, bytes);
4157 if (res) {
4158 tkr.record((address)base, bytes);
4159 }
4160
4161 } else {
4162 res = os::Linux::release_memory_special_impl(base, bytes);
4163 }
4164 return res;
4165 }
4166
4167 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
4168 assert(UseLargePages, "only for large pages");
4169 bool res;
4170
4171 if (UseSHM) {
4172 res = os::Linux::release_memory_special_shm(base, bytes);
4173 } else {
4174 assert(UseHugeTLBFS, "must be");
4175 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4176 }
4177 return res;
4178 }
4179
4180 size_t os::large_page_size() {
4181 return _large_page_size;
4182 }
4183
4184 // With SysV SHM the entire memory region must be allocated as shared
4185 // memory.
4186 // HugeTLBFS allows application to commit large page memory on demand.
4187 // However, when committing memory with HugeTLBFS fails, the region
4188 // that was supposed to be committed will lose the old reservation
4189 // and allow other threads to steal that memory region. Because of this
4190 // behavior we can't commit HugeTLBFS memory.
4191 bool os::can_commit_large_page_memory() {
4192 return UseTransparentHugePages;
4193 }
4194
4195 bool os::can_execute_large_page_memory() {
4196 return UseTransparentHugePages || UseHugeTLBFS;
4197 }
4198
4199 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4200 assert(file_desc >= 0, "file_desc is not valid");
4201 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4202 if (result != NULL) {
4203 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4204 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4205 }
4206 }
4207 return result;
4208 }
4209
4210 // Reserve memory at an arbitrary address, only if that area is
4211 // available (and not reserved for something else).
4212
4213 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4214 // Assert only that the size is a multiple of the page size, since
4215 // that's all that mmap requires, and since that's all we really know
4216 // about at this low abstraction level. If we need higher alignment,
4217 // we can either pass an alignment to this method or verify alignment
4218 // in one of the methods further up the call chain. See bug 5044738.
4219 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4220
4221 // Repeatedly allocate blocks until the block is allocated at the
4222 // right spot.
4223
4224 // Linux mmap allows caller to pass an address as hint; give it a try first,
4225 // if kernel honors the hint then we can return immediately.
4226 char * addr = anon_mmap(requested_addr, bytes, false);
4227 if (addr == requested_addr) {
4228 return requested_addr;
4229 }
4230
4231 if (addr != NULL) {
4232 // mmap() is successful but it fails to reserve at the requested address
4233 anon_munmap(addr, bytes);
4234 }
4235
4236 return NULL;
4237 }
4238
4239 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4240 void os::infinite_sleep() {
4241 while (true) { // sleep forever ...
4242 ::sleep(100); // ... 100 seconds at a time
4243 }
4244 }
4245
4246 // Used to convert frequent JVM_Yield() to nops
4247 bool os::dont_yield() {
4248 return DontYieldALot;
4249 }
4250
4251 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4252 // actually give up the CPU. Since skip buddy (v2.6.28):
4253 //
4254 // * Sets the yielding task as skip buddy for current CPU's run queue.
4255 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4256 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4257 //
4258 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4259 // getting re-scheduled immediately.
4260 //
4261 void os::naked_yield() {
4262 sched_yield();
4263 }
4264
4265 ////////////////////////////////////////////////////////////////////////////////
4266 // thread priority support
4267
4268 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4269 // only supports dynamic priority, static priority must be zero. For real-time
4270 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4271 // However, for large multi-threaded applications, SCHED_RR is not only slower
4272 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4273 // of 5 runs - Sep 2005).
4274 //
4275 // The following code actually changes the niceness of kernel-thread/LWP. It
4276 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4277 // not the entire user process, and user level threads are 1:1 mapped to kernel
4278 // threads. It has always been the case, but could change in the future. For
4279 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4280 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4281 // (e.g., root privilege or CAP_SYS_NICE capability).
4282
4283 int os::java_to_os_priority[CriticalPriority + 1] = {
4284 19, // 0 Entry should never be used
4285
4286 4, // 1 MinPriority
4287 3, // 2
4288 2, // 3
4289
4290 1, // 4
4291 0, // 5 NormPriority
4292 -1, // 6
4293
4294 -2, // 7
4295 -3, // 8
4296 -4, // 9 NearMaxPriority
4297
4298 -5, // 10 MaxPriority
4299
4300 -5 // 11 CriticalPriority
4301 };
4302
4303 static int prio_init() {
4304 if (ThreadPriorityPolicy == 1) {
4305 if (geteuid() != 0) {
4306 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4307 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4308 "e.g., being the root user. If the necessary permission is not " \
4309 "possessed, changes to priority will be silently ignored.");
4310 }
4311 }
4312 }
4313 if (UseCriticalJavaThreadPriority) {
4314 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4315 }
4316 return 0;
4317 }
4318
4319 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4320 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4321
4322 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4323 return (ret == 0) ? OS_OK : OS_ERR;
4324 }
4325
4326 OSReturn os::get_native_priority(const Thread* const thread,
4327 int *priority_ptr) {
4328 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4329 *priority_ptr = java_to_os_priority[NormPriority];
4330 return OS_OK;
4331 }
4332
4333 errno = 0;
4334 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4335 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4336 }
4337
4338 ////////////////////////////////////////////////////////////////////////////////
4339 // suspend/resume support
4340
4341 // The low-level signal-based suspend/resume support is a remnant from the
4342 // old VM-suspension that used to be for java-suspension, safepoints etc,
4343 // within hotspot. Currently used by JFR's OSThreadSampler
4344 //
4345 // The remaining code is greatly simplified from the more general suspension
4346 // code that used to be used.
4347 //
4348 // The protocol is quite simple:
4349 // - suspend:
4350 // - sends a signal to the target thread
4351 // - polls the suspend state of the osthread using a yield loop
4352 // - target thread signal handler (SR_handler) sets suspend state
4353 // and blocks in sigsuspend until continued
4354 // - resume:
4355 // - sets target osthread state to continue
4356 // - sends signal to end the sigsuspend loop in the SR_handler
4357 //
4358 // Note that the SR_lock plays no role in this suspend/resume protocol,
4359 // but is checked for NULL in SR_handler as a thread termination indicator.
4360 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4361 //
4362 // Note that resume_clear_context() and suspend_save_context() are needed
4363 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4364 // which in part is used by:
4365 // - Forte Analyzer: AsyncGetCallTrace()
4366 // - StackBanging: get_frame_at_stack_banging_point()
4367
4368 static void resume_clear_context(OSThread *osthread) {
4369 osthread->set_ucontext(NULL);
4370 osthread->set_siginfo(NULL);
4371 }
4372
4373 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4374 ucontext_t* context) {
4375 osthread->set_ucontext(context);
4376 osthread->set_siginfo(siginfo);
4377 }
4378
4379 // Handler function invoked when a thread's execution is suspended or
4380 // resumed. We have to be careful that only async-safe functions are
4381 // called here (Note: most pthread functions are not async safe and
4382 // should be avoided.)
4383 //
4384 // Note: sigwait() is a more natural fit than sigsuspend() from an
4385 // interface point of view, but sigwait() prevents the signal hander
4386 // from being run. libpthread would get very confused by not having
4387 // its signal handlers run and prevents sigwait()'s use with the
4388 // mutex granting granting signal.
4389 //
4390 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4391 //
4392 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4393 // Save and restore errno to avoid confusing native code with EINTR
4394 // after sigsuspend.
4395 int old_errno = errno;
4396
4397 Thread* thread = Thread::current_or_null_safe();
4398 assert(thread != NULL, "Missing current thread in SR_handler");
4399
4400 // On some systems we have seen signal delivery get "stuck" until the signal
4401 // mask is changed as part of thread termination. Check that the current thread
4402 // has not already terminated (via SR_lock()) - else the following assertion
4403 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4404 // destructor has completed.
4405
4406 if (thread->SR_lock() == NULL) {
4407 return;
4408 }
4409
4410 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4411
4412 OSThread* osthread = thread->osthread();
4413
4414 os::SuspendResume::State current = osthread->sr.state();
4415 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4416 suspend_save_context(osthread, siginfo, context);
4417
4418 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4419 os::SuspendResume::State state = osthread->sr.suspended();
4420 if (state == os::SuspendResume::SR_SUSPENDED) {
4421 sigset_t suspend_set; // signals for sigsuspend()
4422 sigemptyset(&suspend_set);
4423 // get current set of blocked signals and unblock resume signal
4424 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4425 sigdelset(&suspend_set, SR_signum);
4426
4427 sr_semaphore.signal();
4428 // wait here until we are resumed
4429 while (1) {
4430 sigsuspend(&suspend_set);
4431
4432 os::SuspendResume::State result = osthread->sr.running();
4433 if (result == os::SuspendResume::SR_RUNNING) {
4434 sr_semaphore.signal();
4435 break;
4436 }
4437 }
4438
4439 } else if (state == os::SuspendResume::SR_RUNNING) {
4440 // request was cancelled, continue
4441 } else {
4442 ShouldNotReachHere();
4443 }
4444
4445 resume_clear_context(osthread);
4446 } else if (current == os::SuspendResume::SR_RUNNING) {
4447 // request was cancelled, continue
4448 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4449 // ignore
4450 } else {
4451 // ignore
4452 }
4453
4454 errno = old_errno;
4455 }
4456
4457 static int SR_initialize() {
4458 struct sigaction act;
4459 char *s;
4460
4461 // Get signal number to use for suspend/resume
4462 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4463 int sig = ::strtol(s, 0, 10);
4464 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4465 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4466 SR_signum = sig;
4467 } else {
4468 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4469 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4470 }
4471 }
4472
4473 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4474 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4475
4476 sigemptyset(&SR_sigset);
4477 sigaddset(&SR_sigset, SR_signum);
4478
4479 // Set up signal handler for suspend/resume
4480 act.sa_flags = SA_RESTART|SA_SIGINFO;
4481 act.sa_handler = (void (*)(int)) SR_handler;
4482
4483 // SR_signum is blocked by default.
4484 // 4528190 - We also need to block pthread restart signal (32 on all
4485 // supported Linux platforms). Note that LinuxThreads need to block
4486 // this signal for all threads to work properly. So we don't have
4487 // to use hard-coded signal number when setting up the mask.
4488 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4489
4490 if (sigaction(SR_signum, &act, 0) == -1) {
4491 return -1;
4492 }
4493
4494 // Save signal flag
4495 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4496 return 0;
4497 }
4498
4499 static int sr_notify(OSThread* osthread) {
4500 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4501 assert_status(status == 0, status, "pthread_kill");
4502 return status;
4503 }
4504
4505 // "Randomly" selected value for how long we want to spin
4506 // before bailing out on suspending a thread, also how often
4507 // we send a signal to a thread we want to resume
4508 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4509 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4510
4511 // returns true on success and false on error - really an error is fatal
4512 // but this seems the normal response to library errors
4513 static bool do_suspend(OSThread* osthread) {
4514 assert(osthread->sr.is_running(), "thread should be running");
4515 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4516
4517 // mark as suspended and send signal
4518 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4519 // failed to switch, state wasn't running?
4520 ShouldNotReachHere();
4521 return false;
4522 }
4523
4524 if (sr_notify(osthread) != 0) {
4525 ShouldNotReachHere();
4526 }
4527
4528 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4529 while (true) {
4530 if (sr_semaphore.timedwait(2)) {
4531 break;
4532 } else {
4533 // timeout
4534 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4535 if (cancelled == os::SuspendResume::SR_RUNNING) {
4536 return false;
4537 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4538 // make sure that we consume the signal on the semaphore as well
4539 sr_semaphore.wait();
4540 break;
4541 } else {
4542 ShouldNotReachHere();
4543 return false;
4544 }
4545 }
4546 }
4547
4548 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4549 return true;
4550 }
4551
4552 static void do_resume(OSThread* osthread) {
4553 assert(osthread->sr.is_suspended(), "thread should be suspended");
4554 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4555
4556 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4557 // failed to switch to WAKEUP_REQUEST
4558 ShouldNotReachHere();
4559 return;
4560 }
4561
4562 while (true) {
4563 if (sr_notify(osthread) == 0) {
4564 if (sr_semaphore.timedwait(2)) {
4565 if (osthread->sr.is_running()) {
4566 return;
4567 }
4568 }
4569 } else {
4570 ShouldNotReachHere();
4571 }
4572 }
4573
4574 guarantee(osthread->sr.is_running(), "Must be running!");
4575 }
4576
4577 ///////////////////////////////////////////////////////////////////////////////////
4578 // signal handling (except suspend/resume)
4579
4580 // This routine may be used by user applications as a "hook" to catch signals.
4581 // The user-defined signal handler must pass unrecognized signals to this
4582 // routine, and if it returns true (non-zero), then the signal handler must
4583 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4584 // routine will never retun false (zero), but instead will execute a VM panic
4585 // routine kill the process.
4586 //
4587 // If this routine returns false, it is OK to call it again. This allows
4588 // the user-defined signal handler to perform checks either before or after
4589 // the VM performs its own checks. Naturally, the user code would be making
4590 // a serious error if it tried to handle an exception (such as a null check
4591 // or breakpoint) that the VM was generating for its own correct operation.
4592 //
4593 // This routine may recognize any of the following kinds of signals:
4594 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4595 // It should be consulted by handlers for any of those signals.
4596 //
4597 // The caller of this routine must pass in the three arguments supplied
4598 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4599 // field of the structure passed to sigaction(). This routine assumes that
4600 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4601 //
4602 // Note that the VM will print warnings if it detects conflicting signal
4603 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4604 //
4605 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4606 siginfo_t* siginfo,
4607 void* ucontext,
4608 int abort_if_unrecognized);
4609
4610 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4611 assert(info != NULL && uc != NULL, "it must be old kernel");
4612 int orig_errno = errno; // Preserve errno value over signal handler.
4613 JVM_handle_linux_signal(sig, info, uc, true);
4614 errno = orig_errno;
4615 }
4616
4617
4618 // This boolean allows users to forward their own non-matching signals
4619 // to JVM_handle_linux_signal, harmlessly.
4620 bool os::Linux::signal_handlers_are_installed = false;
4621
4622 // For signal-chaining
4623 bool os::Linux::libjsig_is_loaded = false;
4624 typedef struct sigaction *(*get_signal_t)(int);
4625 get_signal_t os::Linux::get_signal_action = NULL;
4626
4627 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4628 struct sigaction *actp = NULL;
4629
4630 if (libjsig_is_loaded) {
4631 // Retrieve the old signal handler from libjsig
4632 actp = (*get_signal_action)(sig);
4633 }
4634 if (actp == NULL) {
4635 // Retrieve the preinstalled signal handler from jvm
4636 actp = os::Posix::get_preinstalled_handler(sig);
4637 }
4638
4639 return actp;
4640 }
4641
4642 static bool call_chained_handler(struct sigaction *actp, int sig,
4643 siginfo_t *siginfo, void *context) {
4644 // Call the old signal handler
4645 if (actp->sa_handler == SIG_DFL) {
4646 // It's more reasonable to let jvm treat it as an unexpected exception
4647 // instead of taking the default action.
4648 return false;
4649 } else if (actp->sa_handler != SIG_IGN) {
4650 if ((actp->sa_flags & SA_NODEFER) == 0) {
4651 // automaticlly block the signal
4652 sigaddset(&(actp->sa_mask), sig);
4653 }
4654
4655 sa_handler_t hand = NULL;
4656 sa_sigaction_t sa = NULL;
4657 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4658 // retrieve the chained handler
4659 if (siginfo_flag_set) {
4660 sa = actp->sa_sigaction;
4661 } else {
4662 hand = actp->sa_handler;
4663 }
4664
4665 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4666 actp->sa_handler = SIG_DFL;
4667 }
4668
4669 // try to honor the signal mask
4670 sigset_t oset;
4671 sigemptyset(&oset);
4672 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4673
4674 // call into the chained handler
4675 if (siginfo_flag_set) {
4676 (*sa)(sig, siginfo, context);
4677 } else {
4678 (*hand)(sig);
4679 }
4680
4681 // restore the signal mask
4682 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4683 }
4684 // Tell jvm's signal handler the signal is taken care of.
4685 return true;
4686 }
4687
4688 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4689 bool chained = false;
4690 // signal-chaining
4691 if (UseSignalChaining) {
4692 struct sigaction *actp = get_chained_signal_action(sig);
4693 if (actp != NULL) {
4694 chained = call_chained_handler(actp, sig, siginfo, context);
4695 }
4696 }
4697 return chained;
4698 }
4699
4700 // for diagnostic
4701 int sigflags[NSIG];
4702
4703 int os::Linux::get_our_sigflags(int sig) {
4704 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4705 return sigflags[sig];
4706 }
4707
4708 void os::Linux::set_our_sigflags(int sig, int flags) {
4709 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4710 if (sig > 0 && sig < NSIG) {
4711 sigflags[sig] = flags;
4712 }
4713 }
4714
4715 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4716 // Check for overwrite.
4717 struct sigaction oldAct;
4718 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4719
4720 void* oldhand = oldAct.sa_sigaction
4721 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4722 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4723 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4724 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4725 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4726 if (AllowUserSignalHandlers || !set_installed) {
4727 // Do not overwrite; user takes responsibility to forward to us.
4728 return;
4729 } else if (UseSignalChaining) {
4730 // save the old handler in jvm
4731 os::Posix::save_preinstalled_handler(sig, oldAct);
4732 // libjsig also interposes the sigaction() call below and saves the
4733 // old sigaction on it own.
4734 } else {
4735 fatal("Encountered unexpected pre-existing sigaction handler "
4736 "%#lx for signal %d.", (long)oldhand, sig);
4737 }
4738 }
4739
4740 struct sigaction sigAct;
4741 sigfillset(&(sigAct.sa_mask));
4742 sigAct.sa_handler = SIG_DFL;
4743 if (!set_installed) {
4744 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4745 } else {
4746 sigAct.sa_sigaction = signalHandler;
4747 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4748 }
4749 // Save flags, which are set by ours
4750 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4751 sigflags[sig] = sigAct.sa_flags;
4752
4753 int ret = sigaction(sig, &sigAct, &oldAct);
4754 assert(ret == 0, "check");
4755
4756 void* oldhand2 = oldAct.sa_sigaction
4757 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4758 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4759 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4760 }
4761
4762 // install signal handlers for signals that HotSpot needs to
4763 // handle in order to support Java-level exception handling.
4764
4765 void os::Linux::install_signal_handlers() {
4766 if (!signal_handlers_are_installed) {
4767 signal_handlers_are_installed = true;
4768
4769 // signal-chaining
4770 typedef void (*signal_setting_t)();
4771 signal_setting_t begin_signal_setting = NULL;
4772 signal_setting_t end_signal_setting = NULL;
4773 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4774 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4775 if (begin_signal_setting != NULL) {
4776 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4777 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4778 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4779 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4780 libjsig_is_loaded = true;
4781 assert(UseSignalChaining, "should enable signal-chaining");
4782 }
4783 if (libjsig_is_loaded) {
4784 // Tell libjsig jvm is setting signal handlers
4785 (*begin_signal_setting)();
4786 }
4787
4788 set_signal_handler(SIGSEGV, true);
4789 set_signal_handler(SIGPIPE, true);
4790 set_signal_handler(SIGBUS, true);
4791 set_signal_handler(SIGILL, true);
4792 set_signal_handler(SIGFPE, true);
4793 #if defined(PPC64)
4794 set_signal_handler(SIGTRAP, true);
4795 #endif
4796 set_signal_handler(SIGXFSZ, true);
4797
4798 if (libjsig_is_loaded) {
4799 // Tell libjsig jvm finishes setting signal handlers
4800 (*end_signal_setting)();
4801 }
4802
4803 // We don't activate signal checker if libjsig is in place, we trust ourselves
4804 // and if UserSignalHandler is installed all bets are off.
4805 // Log that signal checking is off only if -verbose:jni is specified.
4806 if (CheckJNICalls) {
4807 if (libjsig_is_loaded) {
4808 log_debug(jni, resolve)("Info: libjsig is activated, all active signal checking is disabled");
4809 check_signals = false;
4810 }
4811 if (AllowUserSignalHandlers) {
4812 log_debug(jni, resolve)("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4813 check_signals = false;
4814 }
4815 }
4816 }
4817 }
4818
4819 // This is the fastest way to get thread cpu time on Linux.
4820 // Returns cpu time (user+sys) for any thread, not only for current.
4821 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4822 // It might work on 2.6.10+ with a special kernel/glibc patch.
4823 // For reference, please, see IEEE Std 1003.1-2004:
4824 // http://www.unix.org/single_unix_specification
4825
4826 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4827 struct timespec tp;
4828 int rc = os::Posix::clock_gettime(clockid, &tp);
4829 assert(rc == 0, "clock_gettime is expected to return 0 code");
4830
4831 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4832 }
4833
4834 /////
4835 // glibc on Linux platform uses non-documented flag
4836 // to indicate, that some special sort of signal
4837 // trampoline is used.
4838 // We will never set this flag, and we should
4839 // ignore this flag in our diagnostic
4840 #ifdef SIGNIFICANT_SIGNAL_MASK
4841 #undef SIGNIFICANT_SIGNAL_MASK
4842 #endif
4843 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4844
4845 static const char* get_signal_handler_name(address handler,
4846 char* buf, int buflen) {
4847 int offset = 0;
4848 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4849 if (found) {
4850 // skip directory names
4851 const char *p1, *p2;
4852 p1 = buf;
4853 size_t len = strlen(os::file_separator());
4854 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4855 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4856 } else {
4857 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4858 }
4859 return buf;
4860 }
4861
4862 static void print_signal_handler(outputStream* st, int sig,
4863 char* buf, size_t buflen) {
4864 struct sigaction sa;
4865
4866 sigaction(sig, NULL, &sa);
4867
4868 // See comment for SIGNIFICANT_SIGNAL_MASK define
4869 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4870
4871 st->print("%s: ", os::exception_name(sig, buf, buflen));
4872
4873 address handler = (sa.sa_flags & SA_SIGINFO)
4874 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4875 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4876
4877 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4878 st->print("SIG_DFL");
4879 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4880 st->print("SIG_IGN");
4881 } else {
4882 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4883 }
4884
4885 st->print(", sa_mask[0]=");
4886 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4887
4888 address rh = VMError::get_resetted_sighandler(sig);
4889 // May be, handler was resetted by VMError?
4890 if (rh != NULL) {
4891 handler = rh;
4892 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4893 }
4894
4895 st->print(", sa_flags=");
4896 os::Posix::print_sa_flags(st, sa.sa_flags);
4897
4898 // Check: is it our handler?
4899 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4900 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4901 // It is our signal handler
4902 // check for flags, reset system-used one!
4903 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4904 st->print(
4905 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4906 os::Linux::get_our_sigflags(sig));
4907 }
4908 }
4909 st->cr();
4910 }
4911
4912
4913 #define DO_SIGNAL_CHECK(sig) \
4914 do { \
4915 if (!sigismember(&check_signal_done, sig)) { \
4916 os::Linux::check_signal_handler(sig); \
4917 } \
4918 } while (0)
4919
4920 // This method is a periodic task to check for misbehaving JNI applications
4921 // under CheckJNI, we can add any periodic checks here
4922
4923 void os::run_periodic_checks() {
4924 if (check_signals == false) return;
4925
4926 // SEGV and BUS if overridden could potentially prevent
4927 // generation of hs*.log in the event of a crash, debugging
4928 // such a case can be very challenging, so we absolutely
4929 // check the following for a good measure:
4930 DO_SIGNAL_CHECK(SIGSEGV);
4931 DO_SIGNAL_CHECK(SIGILL);
4932 DO_SIGNAL_CHECK(SIGFPE);
4933 DO_SIGNAL_CHECK(SIGBUS);
4934 DO_SIGNAL_CHECK(SIGPIPE);
4935 DO_SIGNAL_CHECK(SIGXFSZ);
4936 #if defined(PPC64)
4937 DO_SIGNAL_CHECK(SIGTRAP);
4938 #endif
4939
4940 // ReduceSignalUsage allows the user to override these handlers
4941 // see comments at the very top and jvm_md.h
4942 if (!ReduceSignalUsage) {
4943 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4944 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4945 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4946 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4947 }
4948
4949 DO_SIGNAL_CHECK(SR_signum);
4950 }
4951
4952 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4953
4954 static os_sigaction_t os_sigaction = NULL;
4955
4956 void os::Linux::check_signal_handler(int sig) {
4957 char buf[O_BUFLEN];
4958 address jvmHandler = NULL;
4959
4960
4961 struct sigaction act;
4962 if (os_sigaction == NULL) {
4963 // only trust the default sigaction, in case it has been interposed
4964 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4965 if (os_sigaction == NULL) return;
4966 }
4967
4968 os_sigaction(sig, (struct sigaction*)NULL, &act);
4969
4970
4971 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4972
4973 address thisHandler = (act.sa_flags & SA_SIGINFO)
4974 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4975 : CAST_FROM_FN_PTR(address, act.sa_handler);
4976
4977
4978 switch (sig) {
4979 case SIGSEGV:
4980 case SIGBUS:
4981 case SIGFPE:
4982 case SIGPIPE:
4983 case SIGILL:
4984 case SIGXFSZ:
4985 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4986 break;
4987
4988 case SHUTDOWN1_SIGNAL:
4989 case SHUTDOWN2_SIGNAL:
4990 case SHUTDOWN3_SIGNAL:
4991 case BREAK_SIGNAL:
4992 jvmHandler = (address)user_handler();
4993 break;
4994
4995 default:
4996 if (sig == SR_signum) {
4997 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4998 } else {
4999 return;
5000 }
5001 break;
5002 }
5003
5004 if (thisHandler != jvmHandler) {
5005 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
5006 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
5007 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
5008 // No need to check this sig any longer
5009 sigaddset(&check_signal_done, sig);
5010 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
5011 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5012 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5013 exception_name(sig, buf, O_BUFLEN));
5014 }
5015 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5016 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5017 tty->print("expected:");
5018 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
5019 tty->cr();
5020 tty->print(" found:");
5021 os::Posix::print_sa_flags(tty, act.sa_flags);
5022 tty->cr();
5023 // No need to check this sig any longer
5024 sigaddset(&check_signal_done, sig);
5025 }
5026
5027 // Dump all the signal
5028 if (sigismember(&check_signal_done, sig)) {
5029 print_signal_handlers(tty, buf, O_BUFLEN);
5030 }
5031 }
5032
5033 extern void report_error(char* file_name, int line_no, char* title,
5034 char* format, ...);
5035
5036 // this is called _before_ most of the global arguments have been parsed
5037 void os::init(void) {
5038 char dummy; // used to get a guess on initial stack address
5039
5040 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5041
5042 init_random(1234567);
5043
5044 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5045 if (Linux::page_size() == -1) {
5046 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5047 os::strerror(errno));
5048 }
5049 init_page_sizes((size_t) Linux::page_size());
5050
5051 Linux::initialize_system_info();
5052
5053 os::Linux::CPUPerfTicks pticks;
5054 bool res = os::Linux::get_tick_information(&pticks, -1);
5055
5056 if (res && pticks.has_steal_ticks) {
5057 has_initial_tick_info = true;
5058 initial_total_ticks = pticks.total;
5059 initial_steal_ticks = pticks.steal;
5060 }
5061
5062 // _main_thread points to the thread that created/loaded the JVM.
5063 Linux::_main_thread = pthread_self();
5064
5065 // retrieve entry point for pthread_setname_np
5066 Linux::_pthread_setname_np =
5067 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5068
5069 os::Posix::init();
5070
5071 initial_time_count = javaTimeNanos();
5072
5073 // Always warn if no monotonic clock available
5074 if (!os::Posix::supports_monotonic_clock()) {
5075 warning("No monotonic clock was available - timed services may " \
5076 "be adversely affected if the time-of-day clock changes");
5077 }
5078 }
5079
5080 // To install functions for atexit system call
5081 extern "C" {
5082 static void perfMemory_exit_helper() {
5083 perfMemory_exit();
5084 }
5085 }
5086
5087 void os::pd_init_container_support() {
5088 OSContainer::init();
5089 }
5090
5091 void os::Linux::numa_init() {
5092
5093 // Java can be invoked as
5094 // 1. Without numactl and heap will be allocated/configured on all nodes as
5095 // per the system policy.
5096 // 2. With numactl --interleave:
5097 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5098 // API for membind case bitmask is reset.
5099 // Interleave is only hint and Kernel can fallback to other nodes if
5100 // no memory is available on the target nodes.
5101 // 3. With numactl --membind:
5102 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5103 // interleave case returns bitmask of all nodes.
5104 // numa_all_nodes_ptr holds bitmask of all nodes.
5105 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5106 // bitmask when externally configured to run on all or fewer nodes.
5107
5108 if (!Linux::libnuma_init()) {
5109 UseNUMA = false;
5110 } else {
5111 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5112 // If there's only one node (they start from 0) or if the process
5113 // is bound explicitly to a single node using membind, disable NUMA.
5114 UseNUMA = false;
5115 } else {
5116
5117 LogTarget(Info,os) log;
5118 LogStream ls(log);
5119
5120 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5121
5122 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5123 const char* numa_mode = "membind";
5124
5125 if (Linux::is_running_in_interleave_mode()) {
5126 bmp = Linux::_numa_interleave_bitmask;
5127 numa_mode = "interleave";
5128 }
5129
5130 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5131 " Heap will be configured using NUMA memory nodes:", numa_mode);
5132
5133 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5134 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5135 ls.print(" %d", node);
5136 }
5137 }
5138 }
5139 }
5140
5141 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5142 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5143 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5144 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5145 // and disable adaptive resizing.
5146 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5147 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5148 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5149 UseAdaptiveSizePolicy = false;
5150 UseAdaptiveNUMAChunkSizing = false;
5151 }
5152 }
5153
5154 if (!UseNUMA && ForceNUMA) {
5155 UseNUMA = true;
5156 }
5157 }
5158
5159 // this is called _after_ the global arguments have been parsed
5160 jint os::init_2(void) {
5161
5162 // This could be set after os::Posix::init() but all platforms
5163 // have to set it the same so we have to mirror Solaris.
5164 DEBUG_ONLY(os::set_mutex_init_done();)
5165
5166 os::Posix::init_2();
5167
5168 Linux::fast_thread_clock_init();
5169
5170 // initialize suspend/resume support - must do this before signal_sets_init()
5171 if (SR_initialize() != 0) {
5172 perror("SR_initialize failed");
5173 return JNI_ERR;
5174 }
5175
5176 Linux::signal_sets_init();
5177 Linux::install_signal_handlers();
5178 // Initialize data for jdk.internal.misc.Signal
5179 if (!ReduceSignalUsage) {
5180 jdk_misc_signal_init();
5181 }
5182
5183 if (AdjustStackSizeForTLS) {
5184 get_minstack_init();
5185 }
5186
5187 // Check and sets minimum stack sizes against command line options
5188 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5189 return JNI_ERR;
5190 }
5191
5192 #if defined(IA32)
5193 // Need to ensure we've determined the process's initial stack to
5194 // perform the workaround
5195 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5196 workaround_expand_exec_shield_cs_limit();
5197 #else
5198 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5199 if (!suppress_primordial_thread_resolution) {
5200 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5201 }
5202 #endif
5203
5204 Linux::libpthread_init();
5205 Linux::sched_getcpu_init();
5206 log_info(os)("HotSpot is running with %s, %s",
5207 Linux::glibc_version(), Linux::libpthread_version());
5208
5209 if (UseNUMA) {
5210 Linux::numa_init();
5211 }
5212
5213 if (MaxFDLimit) {
5214 // set the number of file descriptors to max. print out error
5215 // if getrlimit/setrlimit fails but continue regardless.
5216 struct rlimit nbr_files;
5217 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5218 if (status != 0) {
5219 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5220 } else {
5221 nbr_files.rlim_cur = nbr_files.rlim_max;
5222 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5223 if (status != 0) {
5224 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5225 }
5226 }
5227 }
5228
5229 // at-exit methods are called in the reverse order of their registration.
5230 // atexit functions are called on return from main or as a result of a
5231 // call to exit(3C). There can be only 32 of these functions registered
5232 // and atexit() does not set errno.
5233
5234 if (PerfAllowAtExitRegistration) {
5235 // only register atexit functions if PerfAllowAtExitRegistration is set.
5236 // atexit functions can be delayed until process exit time, which
5237 // can be problematic for embedded VM situations. Embedded VMs should
5238 // call DestroyJavaVM() to assure that VM resources are released.
5239
5240 // note: perfMemory_exit_helper atexit function may be removed in
5241 // the future if the appropriate cleanup code can be added to the
5242 // VM_Exit VMOperation's doit method.
5243 if (atexit(perfMemory_exit_helper) != 0) {
5244 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5245 }
5246 }
5247
5248 // initialize thread priority policy
5249 prio_init();
5250
5251 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5252 set_coredump_filter(DAX_SHARED_BIT);
5253 }
5254
5255 if (DumpPrivateMappingsInCore) {
5256 set_coredump_filter(FILE_BACKED_PVT_BIT);
5257 }
5258
5259 if (DumpSharedMappingsInCore) {
5260 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5261 }
5262
5263 return JNI_OK;
5264 }
5265
5266 // Mark the polling page as unreadable
5267 void os::make_polling_page_unreadable(void) {
5268 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
5269 fatal("Could not disable polling page");
5270 }
5271 }
5272
5273 // Mark the polling page as readable
5274 void os::make_polling_page_readable(void) {
5275 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5276 fatal("Could not enable polling page");
5277 }
5278 }
5279
5280 // older glibc versions don't have this macro (which expands to
5281 // an optimized bit-counting function) so we have to roll our own
5282 #ifndef CPU_COUNT
5283
5284 static int _cpu_count(const cpu_set_t* cpus) {
5285 int count = 0;
5286 // only look up to the number of configured processors
5287 for (int i = 0; i < os::processor_count(); i++) {
5288 if (CPU_ISSET(i, cpus)) {
5289 count++;
5290 }
5291 }
5292 return count;
5293 }
5294
5295 #define CPU_COUNT(cpus) _cpu_count(cpus)
5296
5297 #endif // CPU_COUNT
5298
5299 // Get the current number of available processors for this process.
5300 // This value can change at any time during a process's lifetime.
5301 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5302 // If it appears there may be more than 1024 processors then we do a
5303 // dynamic check - see 6515172 for details.
5304 // If anything goes wrong we fallback to returning the number of online
5305 // processors - which can be greater than the number available to the process.
5306 int os::Linux::active_processor_count() {
5307 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5308 cpu_set_t* cpus_p = &cpus;
5309 int cpus_size = sizeof(cpu_set_t);
5310
5311 int configured_cpus = os::processor_count(); // upper bound on available cpus
5312 int cpu_count = 0;
5313
5314 // old build platforms may not support dynamic cpu sets
5315 #ifdef CPU_ALLOC
5316
5317 // To enable easy testing of the dynamic path on different platforms we
5318 // introduce a diagnostic flag: UseCpuAllocPath
5319 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5320 // kernel may use a mask bigger than cpu_set_t
5321 log_trace(os)("active_processor_count: using dynamic path %s"
5322 "- configured processors: %d",
5323 UseCpuAllocPath ? "(forced) " : "",
5324 configured_cpus);
5325 cpus_p = CPU_ALLOC(configured_cpus);
5326 if (cpus_p != NULL) {
5327 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5328 // zero it just to be safe
5329 CPU_ZERO_S(cpus_size, cpus_p);
5330 }
5331 else {
5332 // failed to allocate so fallback to online cpus
5333 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5334 log_trace(os)("active_processor_count: "
5335 "CPU_ALLOC failed (%s) - using "
5336 "online processor count: %d",
5337 os::strerror(errno), online_cpus);
5338 return online_cpus;
5339 }
5340 }
5341 else {
5342 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5343 configured_cpus);
5344 }
5345 #else // CPU_ALLOC
5346 // these stubs won't be executed
5347 #define CPU_COUNT_S(size, cpus) -1
5348 #define CPU_FREE(cpus)
5349
5350 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5351 configured_cpus);
5352 #endif // CPU_ALLOC
5353
5354 // pid 0 means the current thread - which we have to assume represents the process
5355 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5356 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5357 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5358 }
5359 else {
5360 cpu_count = CPU_COUNT(cpus_p);
5361 }
5362 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5363 }
5364 else {
5365 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5366 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5367 "which may exceed available processors", os::strerror(errno), cpu_count);
5368 }
5369
5370 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5371 CPU_FREE(cpus_p);
5372 }
5373
5374 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5375 return cpu_count;
5376 }
5377
5378 // Determine the active processor count from one of
5379 // three different sources:
5380 //
5381 // 1. User option -XX:ActiveProcessorCount
5382 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5383 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5384 //
5385 // Option 1, if specified, will always override.
5386 // If the cgroup subsystem is active and configured, we
5387 // will return the min of the cgroup and option 2 results.
5388 // This is required since tools, such as numactl, that
5389 // alter cpu affinity do not update cgroup subsystem
5390 // cpuset configuration files.
5391 int os::active_processor_count() {
5392 // User has overridden the number of active processors
5393 if (ActiveProcessorCount > 0) {
5394 log_trace(os)("active_processor_count: "
5395 "active processor count set by user : %d",
5396 ActiveProcessorCount);
5397 return ActiveProcessorCount;
5398 }
5399
5400 int active_cpus;
5401 if (OSContainer::is_containerized()) {
5402 active_cpus = OSContainer::active_processor_count();
5403 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5404 active_cpus);
5405 } else {
5406 active_cpus = os::Linux::active_processor_count();
5407 }
5408
5409 return active_cpus;
5410 }
5411
5412 uint os::processor_id() {
5413 const int id = Linux::sched_getcpu();
5414 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5415 return (uint)id;
5416 }
5417
5418 void os::set_native_thread_name(const char *name) {
5419 if (Linux::_pthread_setname_np) {
5420 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5421 snprintf(buf, sizeof(buf), "%s", name);
5422 buf[sizeof(buf) - 1] = '\0';
5423 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5424 // ERANGE should not happen; all other errors should just be ignored.
5425 assert(rc != ERANGE, "pthread_setname_np failed");
5426 }
5427 }
5428
5429 bool os::bind_to_processor(uint processor_id) {
5430 // Not yet implemented.
5431 return false;
5432 }
5433
5434 ///
5435
5436 void os::SuspendedThreadTask::internal_do_task() {
5437 if (do_suspend(_thread->osthread())) {
5438 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5439 do_task(context);
5440 do_resume(_thread->osthread());
5441 }
5442 }
5443
5444 ////////////////////////////////////////////////////////////////////////////////
5445 // debug support
5446
5447 bool os::find(address addr, outputStream* st) {
5448 Dl_info dlinfo;
5449 memset(&dlinfo, 0, sizeof(dlinfo));
5450 if (dladdr(addr, &dlinfo) != 0) {
5451 st->print(PTR_FORMAT ": ", p2i(addr));
5452 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5453 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5454 p2i(addr) - p2i(dlinfo.dli_saddr));
5455 } else if (dlinfo.dli_fbase != NULL) {
5456 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5457 } else {
5458 st->print("<absolute address>");
5459 }
5460 if (dlinfo.dli_fname != NULL) {
5461 st->print(" in %s", dlinfo.dli_fname);
5462 }
5463 if (dlinfo.dli_fbase != NULL) {
5464 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5465 }
5466 st->cr();
5467
5468 if (Verbose) {
5469 // decode some bytes around the PC
5470 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5471 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5472 address lowest = (address) dlinfo.dli_sname;
5473 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5474 if (begin < lowest) begin = lowest;
5475 Dl_info dlinfo2;
5476 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5477 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5478 end = (address) dlinfo2.dli_saddr;
5479 }
5480 Disassembler::decode(begin, end, st);
5481 }
5482 return true;
5483 }
5484 return false;
5485 }
5486
5487 ////////////////////////////////////////////////////////////////////////////////
5488 // misc
5489
5490 // This does not do anything on Linux. This is basically a hook for being
5491 // able to use structured exception handling (thread-local exception filters)
5492 // on, e.g., Win32.
5493 void
5494 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5495 JavaCallArguments* args, Thread* thread) {
5496 f(value, method, args, thread);
5497 }
5498
5499 void os::print_statistics() {
5500 }
5501
5502 bool os::message_box(const char* title, const char* message) {
5503 int i;
5504 fdStream err(defaultStream::error_fd());
5505 for (i = 0; i < 78; i++) err.print_raw("=");
5506 err.cr();
5507 err.print_raw_cr(title);
5508 for (i = 0; i < 78; i++) err.print_raw("-");
5509 err.cr();
5510 err.print_raw_cr(message);
5511 for (i = 0; i < 78; i++) err.print_raw("=");
5512 err.cr();
5513
5514 char buf[16];
5515 // Prevent process from exiting upon "read error" without consuming all CPU
5516 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5517
5518 return buf[0] == 'y' || buf[0] == 'Y';
5519 }
5520
5521 // Is a (classpath) directory empty?
5522 bool os::dir_is_empty(const char* path) {
5523 DIR *dir = NULL;
5524 struct dirent *ptr;
5525
5526 dir = opendir(path);
5527 if (dir == NULL) return true;
5528
5529 // Scan the directory
5530 bool result = true;
5531 while (result && (ptr = readdir(dir)) != NULL) {
5532 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5533 result = false;
5534 }
5535 }
5536 closedir(dir);
5537 return result;
5538 }
5539
5540 // This code originates from JDK's sysOpen and open64_w
5541 // from src/solaris/hpi/src/system_md.c
5542
5543 int os::open(const char *path, int oflag, int mode) {
5544 if (strlen(path) > MAX_PATH - 1) {
5545 errno = ENAMETOOLONG;
5546 return -1;
5547 }
5548
5549 // All file descriptors that are opened in the Java process and not
5550 // specifically destined for a subprocess should have the close-on-exec
5551 // flag set. If we don't set it, then careless 3rd party native code
5552 // might fork and exec without closing all appropriate file descriptors
5553 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5554 // turn might:
5555 //
5556 // - cause end-of-file to fail to be detected on some file
5557 // descriptors, resulting in mysterious hangs, or
5558 //
5559 // - might cause an fopen in the subprocess to fail on a system
5560 // suffering from bug 1085341.
5561 //
5562 // (Yes, the default setting of the close-on-exec flag is a Unix
5563 // design flaw)
5564 //
5565 // See:
5566 // 1085341: 32-bit stdio routines should support file descriptors >255
5567 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5568 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5569 //
5570 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5571 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5572 // because it saves a system call and removes a small window where the flag
5573 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5574 // and we fall back to using FD_CLOEXEC (see below).
5575 #ifdef O_CLOEXEC
5576 oflag |= O_CLOEXEC;
5577 #endif
5578
5579 int fd = ::open64(path, oflag, mode);
5580 if (fd == -1) return -1;
5581
5582 //If the open succeeded, the file might still be a directory
5583 {
5584 struct stat64 buf64;
5585 int ret = ::fstat64(fd, &buf64);
5586 int st_mode = buf64.st_mode;
5587
5588 if (ret != -1) {
5589 if ((st_mode & S_IFMT) == S_IFDIR) {
5590 errno = EISDIR;
5591 ::close(fd);
5592 return -1;
5593 }
5594 } else {
5595 ::close(fd);
5596 return -1;
5597 }
5598 }
5599
5600 #ifdef FD_CLOEXEC
5601 // Validate that the use of the O_CLOEXEC flag on open above worked.
5602 // With recent kernels, we will perform this check exactly once.
5603 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5604 if (!O_CLOEXEC_is_known_to_work) {
5605 int flags = ::fcntl(fd, F_GETFD);
5606 if (flags != -1) {
5607 if ((flags & FD_CLOEXEC) != 0)
5608 O_CLOEXEC_is_known_to_work = 1;
5609 else
5610 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5611 }
5612 }
5613 #endif
5614
5615 return fd;
5616 }
5617
5618
5619 // create binary file, rewriting existing file if required
5620 int os::create_binary_file(const char* path, bool rewrite_existing) {
5621 int oflags = O_WRONLY | O_CREAT;
5622 if (!rewrite_existing) {
5623 oflags |= O_EXCL;
5624 }
5625 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5626 }
5627
5628 // return current position of file pointer
5629 jlong os::current_file_offset(int fd) {
5630 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5631 }
5632
5633 // move file pointer to the specified offset
5634 jlong os::seek_to_file_offset(int fd, jlong offset) {
5635 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5636 }
5637
5638 // This code originates from JDK's sysAvailable
5639 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5640
5641 int os::available(int fd, jlong *bytes) {
5642 jlong cur, end;
5643 int mode;
5644 struct stat64 buf64;
5645
5646 if (::fstat64(fd, &buf64) >= 0) {
5647 mode = buf64.st_mode;
5648 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5649 int n;
5650 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5651 *bytes = n;
5652 return 1;
5653 }
5654 }
5655 }
5656 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5657 return 0;
5658 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5659 return 0;
5660 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5661 return 0;
5662 }
5663 *bytes = end - cur;
5664 return 1;
5665 }
5666
5667 // Map a block of memory.
5668 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5669 char *addr, size_t bytes, bool read_only,
5670 bool allow_exec) {
5671 int prot;
5672 int flags = MAP_PRIVATE;
5673
5674 if (read_only) {
5675 prot = PROT_READ;
5676 } else {
5677 prot = PROT_READ | PROT_WRITE;
5678 }
5679
5680 if (allow_exec) {
5681 prot |= PROT_EXEC;
5682 }
5683
5684 if (addr != NULL) {
5685 flags |= MAP_FIXED;
5686 }
5687
5688 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5689 fd, file_offset);
5690 if (mapped_address == MAP_FAILED) {
5691 return NULL;
5692 }
5693 return mapped_address;
5694 }
5695
5696
5697 // Remap a block of memory.
5698 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5699 char *addr, size_t bytes, bool read_only,
5700 bool allow_exec) {
5701 // same as map_memory() on this OS
5702 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5703 allow_exec);
5704 }
5705
5706
5707 // Unmap a block of memory.
5708 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5709 return munmap(addr, bytes) == 0;
5710 }
5711
5712 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5713
5714 static jlong fast_cpu_time(Thread *thread) {
5715 clockid_t clockid;
5716 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5717 &clockid);
5718 if (rc == 0) {
5719 return os::Linux::fast_thread_cpu_time(clockid);
5720 } else {
5721 // It's possible to encounter a terminated native thread that failed
5722 // to detach itself from the VM - which should result in ESRCH.
5723 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5724 return -1;
5725 }
5726 }
5727
5728 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5729 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5730 // of a thread.
5731 //
5732 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5733 // the fast estimate available on the platform.
5734
5735 jlong os::current_thread_cpu_time() {
5736 if (os::Linux::supports_fast_thread_cpu_time()) {
5737 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5738 } else {
5739 // return user + sys since the cost is the same
5740 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5741 }
5742 }
5743
5744 jlong os::thread_cpu_time(Thread* thread) {
5745 // consistent with what current_thread_cpu_time() returns
5746 if (os::Linux::supports_fast_thread_cpu_time()) {
5747 return fast_cpu_time(thread);
5748 } else {
5749 return slow_thread_cpu_time(thread, true /* user + sys */);
5750 }
5751 }
5752
5753 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5754 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5755 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5756 } else {
5757 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5758 }
5759 }
5760
5761 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5762 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5763 return fast_cpu_time(thread);
5764 } else {
5765 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5766 }
5767 }
5768
5769 // -1 on error.
5770 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5771 pid_t tid = thread->osthread()->thread_id();
5772 char *s;
5773 char stat[2048];
5774 int statlen;
5775 char proc_name[64];
5776 int count;
5777 long sys_time, user_time;
5778 char cdummy;
5779 int idummy;
5780 long ldummy;
5781 FILE *fp;
5782
5783 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5784 fp = fopen(proc_name, "r");
5785 if (fp == NULL) return -1;
5786 statlen = fread(stat, 1, 2047, fp);
5787 stat[statlen] = '\0';
5788 fclose(fp);
5789
5790 // Skip pid and the command string. Note that we could be dealing with
5791 // weird command names, e.g. user could decide to rename java launcher
5792 // to "java 1.4.2 :)", then the stat file would look like
5793 // 1234 (java 1.4.2 :)) R ... ...
5794 // We don't really need to know the command string, just find the last
5795 // occurrence of ")" and then start parsing from there. See bug 4726580.
5796 s = strrchr(stat, ')');
5797 if (s == NULL) return -1;
5798
5799 // Skip blank chars
5800 do { s++; } while (s && isspace(*s));
5801
5802 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5803 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5804 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5805 &user_time, &sys_time);
5806 if (count != 13) return -1;
5807 if (user_sys_cpu_time) {
5808 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5809 } else {
5810 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5811 }
5812 }
5813
5814 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5815 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5816 info_ptr->may_skip_backward = false; // elapsed time not wall time
5817 info_ptr->may_skip_forward = false; // elapsed time not wall time
5818 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5819 }
5820
5821 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5822 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5823 info_ptr->may_skip_backward = false; // elapsed time not wall time
5824 info_ptr->may_skip_forward = false; // elapsed time not wall time
5825 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5826 }
5827
5828 bool os::is_thread_cpu_time_supported() {
5829 return true;
5830 }
5831
5832 // System loadavg support. Returns -1 if load average cannot be obtained.
5833 // Linux doesn't yet have a (official) notion of processor sets,
5834 // so just return the system wide load average.
5835 int os::loadavg(double loadavg[], int nelem) {
5836 return ::getloadavg(loadavg, nelem);
5837 }
5838
5839 void os::pause() {
5840 char filename[MAX_PATH];
5841 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5842 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5843 } else {
5844 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5845 }
5846
5847 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5848 if (fd != -1) {
5849 struct stat buf;
5850 ::close(fd);
5851 while (::stat(filename, &buf) == 0) {
5852 (void)::poll(NULL, 0, 100);
5853 }
5854 } else {
5855 jio_fprintf(stderr,
5856 "Could not open pause file '%s', continuing immediately.\n", filename);
5857 }
5858 }
5859
5860 extern char** environ;
5861
5862 // Run the specified command in a separate process. Return its exit value,
5863 // or -1 on failure (e.g. can't fork a new process).
5864 // Unlike system(), this function can be called from signal handler. It
5865 // doesn't block SIGINT et al.
5866 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5867 const char * argv[4] = {"sh", "-c", cmd, NULL};
5868
5869 pid_t pid ;
5870
5871 if (use_vfork_if_available) {
5872 pid = vfork();
5873 } else {
5874 pid = fork();
5875 }
5876
5877 if (pid < 0) {
5878 // fork failed
5879 return -1;
5880
5881 } else if (pid == 0) {
5882 // child process
5883
5884 execve("/bin/sh", (char* const*)argv, environ);
5885
5886 // execve failed
5887 _exit(-1);
5888
5889 } else {
5890 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5891 // care about the actual exit code, for now.
5892
5893 int status;
5894
5895 // Wait for the child process to exit. This returns immediately if
5896 // the child has already exited. */
5897 while (waitpid(pid, &status, 0) < 0) {
5898 switch (errno) {
5899 case ECHILD: return 0;
5900 case EINTR: break;
5901 default: return -1;
5902 }
5903 }
5904
5905 if (WIFEXITED(status)) {
5906 // The child exited normally; get its exit code.
5907 return WEXITSTATUS(status);
5908 } else if (WIFSIGNALED(status)) {
5909 // The child exited because of a signal
5910 // The best value to return is 0x80 + signal number,
5911 // because that is what all Unix shells do, and because
5912 // it allows callers to distinguish between process exit and
5913 // process death by signal.
5914 return 0x80 + WTERMSIG(status);
5915 } else {
5916 // Unknown exit code; pass it through
5917 return status;
5918 }
5919 }
5920 }
5921
5922 // Get the default path to the core file
5923 // Returns the length of the string
5924 int os::get_core_path(char* buffer, size_t bufferSize) {
5925 /*
5926 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5927 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5928 */
5929 const int core_pattern_len = 129;
5930 char core_pattern[core_pattern_len] = {0};
5931
5932 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5933 if (core_pattern_file == -1) {
5934 return -1;
5935 }
5936
5937 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5938 ::close(core_pattern_file);
5939 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5940 return -1;
5941 }
5942 if (core_pattern[ret-1] == '\n') {
5943 core_pattern[ret-1] = '\0';
5944 } else {
5945 core_pattern[ret] = '\0';
5946 }
5947
5948 // Replace the %p in the core pattern with the process id. NOTE: we do this
5949 // only if the pattern doesn't start with "|", and we support only one %p in
5950 // the pattern.
5951 char *pid_pos = strstr(core_pattern, "%p");
5952 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
5953 int written;
5954
5955 if (core_pattern[0] == '/') {
5956 if (pid_pos != NULL) {
5957 *pid_pos = '\0';
5958 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
5959 current_process_id(), tail);
5960 } else {
5961 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5962 }
5963 } else {
5964 char cwd[PATH_MAX];
5965
5966 const char* p = get_current_directory(cwd, PATH_MAX);
5967 if (p == NULL) {
5968 return -1;
5969 }
5970
5971 if (core_pattern[0] == '|') {
5972 written = jio_snprintf(buffer, bufferSize,
5973 "\"%s\" (or dumping to %s/core.%d)",
5974 &core_pattern[1], p, current_process_id());
5975 } else if (pid_pos != NULL) {
5976 *pid_pos = '\0';
5977 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
5978 current_process_id(), tail);
5979 } else {
5980 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5981 }
5982 }
5983
5984 if (written < 0) {
5985 return -1;
5986 }
5987
5988 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5989 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5990
5991 if (core_uses_pid_file != -1) {
5992 char core_uses_pid = 0;
5993 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5994 ::close(core_uses_pid_file);
5995
5996 if (core_uses_pid == '1') {
5997 jio_snprintf(buffer + written, bufferSize - written,
5998 ".%d", current_process_id());
5999 }
6000 }
6001 }
6002
6003 return strlen(buffer);
6004 }
6005
6006 bool os::start_debugging(char *buf, int buflen) {
6007 int len = (int)strlen(buf);
6008 char *p = &buf[len];
6009
6010 jio_snprintf(p, buflen-len,
6011 "\n\n"
6012 "Do you want to debug the problem?\n\n"
6013 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6014 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6015 "Otherwise, press RETURN to abort...",
6016 os::current_process_id(), os::current_process_id(),
6017 os::current_thread_id(), os::current_thread_id());
6018
6019 bool yes = os::message_box("Unexpected Error", buf);
6020
6021 if (yes) {
6022 // yes, user asked VM to launch debugger
6023 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6024 os::current_process_id(), os::current_process_id());
6025
6026 os::fork_and_exec(buf);
6027 yes = false;
6028 }
6029 return yes;
6030 }
6031
6032
6033 // Java/Compiler thread:
6034 //
6035 // Low memory addresses
6036 // P0 +------------------------+
6037 // | |\ Java thread created by VM does not have glibc
6038 // | glibc guard page | - guard page, attached Java thread usually has
6039 // | |/ 1 glibc guard page.
6040 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6041 // | |\
6042 // | HotSpot Guard Pages | - red, yellow and reserved pages
6043 // | |/
6044 // +------------------------+ JavaThread::stack_reserved_zone_base()
6045 // | |\
6046 // | Normal Stack | -
6047 // | |/
6048 // P2 +------------------------+ Thread::stack_base()
6049 //
6050 // Non-Java thread:
6051 //
6052 // Low memory addresses
6053 // P0 +------------------------+
6054 // | |\
6055 // | glibc guard page | - usually 1 page
6056 // | |/
6057 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6058 // | |\
6059 // | Normal Stack | -
6060 // | |/
6061 // P2 +------------------------+ Thread::stack_base()
6062 //
6063 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6064 // returned from pthread_attr_getstack().
6065 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6066 // of the stack size given in pthread_attr. We work around this for
6067 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6068 //
6069 #ifndef ZERO
6070 static void current_stack_region(address * bottom, size_t * size) {
6071 if (os::is_primordial_thread()) {
6072 // primordial thread needs special handling because pthread_getattr_np()
6073 // may return bogus value.
6074 *bottom = os::Linux::initial_thread_stack_bottom();
6075 *size = os::Linux::initial_thread_stack_size();
6076 } else {
6077 pthread_attr_t attr;
6078
6079 int rslt = pthread_getattr_np(pthread_self(), &attr);
6080
6081 // JVM needs to know exact stack location, abort if it fails
6082 if (rslt != 0) {
6083 if (rslt == ENOMEM) {
6084 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6085 } else {
6086 fatal("pthread_getattr_np failed with error = %d", rslt);
6087 }
6088 }
6089
6090 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6091 fatal("Cannot locate current stack attributes!");
6092 }
6093
6094 // Work around NPTL stack guard error.
6095 size_t guard_size = 0;
6096 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6097 if (rslt != 0) {
6098 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6099 }
6100 *bottom += guard_size;
6101 *size -= guard_size;
6102
6103 pthread_attr_destroy(&attr);
6104
6105 }
6106 assert(os::current_stack_pointer() >= *bottom &&
6107 os::current_stack_pointer() < *bottom + *size, "just checking");
6108 }
6109
6110 address os::current_stack_base() {
6111 address bottom;
6112 size_t size;
6113 current_stack_region(&bottom, &size);
6114 return (bottom + size);
6115 }
6116
6117 size_t os::current_stack_size() {
6118 // This stack size includes the usable stack and HotSpot guard pages
6119 // (for the threads that have Hotspot guard pages).
6120 address bottom;
6121 size_t size;
6122 current_stack_region(&bottom, &size);
6123 return size;
6124 }
6125 #endif
6126
6127 static inline struct timespec get_mtime(const char* filename) {
6128 struct stat st;
6129 int ret = os::stat(filename, &st);
6130 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6131 return st.st_mtim;
6132 }
6133
6134 int os::compare_file_modified_times(const char* file1, const char* file2) {
6135 struct timespec filetime1 = get_mtime(file1);
6136 struct timespec filetime2 = get_mtime(file2);
6137 int diff = filetime1.tv_sec - filetime2.tv_sec;
6138 if (diff == 0) {
6139 return filetime1.tv_nsec - filetime2.tv_nsec;
6140 }
6141 return diff;
6142 }
6143
6144 bool os::supports_map_sync() {
6145 return true;
6146 }
6147
6148 /////////////// Unit tests ///////////////
6149
6150 #ifndef PRODUCT
6151
6152 class TestReserveMemorySpecial : AllStatic {
6153 public:
6154 static void small_page_write(void* addr, size_t size) {
6155 size_t page_size = os::vm_page_size();
6156
6157 char* end = (char*)addr + size;
6158 for (char* p = (char*)addr; p < end; p += page_size) {
6159 *p = 1;
6160 }
6161 }
6162
6163 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6164 if (!UseHugeTLBFS) {
6165 return;
6166 }
6167
6168 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6169
6170 if (addr != NULL) {
6171 small_page_write(addr, size);
6172
6173 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6174 }
6175 }
6176
6177 static void test_reserve_memory_special_huge_tlbfs_only() {
6178 if (!UseHugeTLBFS) {
6179 return;
6180 }
6181
6182 size_t lp = os::large_page_size();
6183
6184 for (size_t size = lp; size <= lp * 10; size += lp) {
6185 test_reserve_memory_special_huge_tlbfs_only(size);
6186 }
6187 }
6188
6189 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6190 size_t lp = os::large_page_size();
6191 size_t ag = os::vm_allocation_granularity();
6192
6193 // sizes to test
6194 const size_t sizes[] = {
6195 lp, lp + ag, lp + lp / 2, lp * 2,
6196 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6197 lp * 10, lp * 10 + lp / 2
6198 };
6199 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6200
6201 // For each size/alignment combination, we test three scenarios:
6202 // 1) with req_addr == NULL
6203 // 2) with a non-null req_addr at which we expect to successfully allocate
6204 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6205 // expect the allocation to either fail or to ignore req_addr
6206
6207 // Pre-allocate two areas; they shall be as large as the largest allocation
6208 // and aligned to the largest alignment we will be testing.
6209 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6210 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6211 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6212 -1, 0);
6213 assert(mapping1 != MAP_FAILED, "should work");
6214
6215 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6216 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6217 -1, 0);
6218 assert(mapping2 != MAP_FAILED, "should work");
6219
6220 // Unmap the first mapping, but leave the second mapping intact: the first
6221 // mapping will serve as a value for a "good" req_addr (case 2). The second
6222 // mapping, still intact, as "bad" req_addr (case 3).
6223 ::munmap(mapping1, mapping_size);
6224
6225 // Case 1
6226 for (int i = 0; i < num_sizes; i++) {
6227 const size_t size = sizes[i];
6228 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6229 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6230 if (p != NULL) {
6231 assert(is_aligned(p, alignment), "must be");
6232 small_page_write(p, size);
6233 os::Linux::release_memory_special_huge_tlbfs(p, size);
6234 }
6235 }
6236 }
6237
6238 // Case 2
6239 for (int i = 0; i < num_sizes; i++) {
6240 const size_t size = sizes[i];
6241 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6242 char* const req_addr = align_up(mapping1, alignment);
6243 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6244 if (p != NULL) {
6245 assert(p == req_addr, "must be");
6246 small_page_write(p, size);
6247 os::Linux::release_memory_special_huge_tlbfs(p, size);
6248 }
6249 }
6250 }
6251
6252 // Case 3
6253 for (int i = 0; i < num_sizes; i++) {
6254 const size_t size = sizes[i];
6255 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6256 char* const req_addr = align_up(mapping2, alignment);
6257 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6258 // as the area around req_addr contains already existing mappings, the API should always
6259 // return NULL (as per contract, it cannot return another address)
6260 assert(p == NULL, "must be");
6261 }
6262 }
6263
6264 ::munmap(mapping2, mapping_size);
6265
6266 }
6267
6268 static void test_reserve_memory_special_huge_tlbfs() {
6269 if (!UseHugeTLBFS) {
6270 return;
6271 }
6272
6273 test_reserve_memory_special_huge_tlbfs_only();
6274 test_reserve_memory_special_huge_tlbfs_mixed();
6275 }
6276
6277 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6278 if (!UseSHM) {
6279 return;
6280 }
6281
6282 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6283
6284 if (addr != NULL) {
6285 assert(is_aligned(addr, alignment), "Check");
6286 assert(is_aligned(addr, os::large_page_size()), "Check");
6287
6288 small_page_write(addr, size);
6289
6290 os::Linux::release_memory_special_shm(addr, size);
6291 }
6292 }
6293
6294 static void test_reserve_memory_special_shm() {
6295 size_t lp = os::large_page_size();
6296 size_t ag = os::vm_allocation_granularity();
6297
6298 for (size_t size = ag; size < lp * 3; size += ag) {
6299 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6300 test_reserve_memory_special_shm(size, alignment);
6301 }
6302 }
6303 }
6304
6305 static void test() {
6306 test_reserve_memory_special_huge_tlbfs();
6307 test_reserve_memory_special_shm();
6308 }
6309 };
6310
6311 void TestReserveMemorySpecial_test() {
6312 TestReserveMemorySpecial::test();
6313 }
6314
6315 #endif