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 <errno.h>
88 # include <dlfcn.h>
89 # include <stdio.h>
90 # include <unistd.h>
91 # include <sys/resource.h>
92 # include <pthread.h>
93 # include <sys/stat.h>
94 # include <sys/time.h>
95 # include <sys/times.h>
96 # include <sys/utsname.h>
97 # include <sys/socket.h>
98 # include <sys/wait.h>
99 # include <pwd.h>
100 # include <poll.h>
101 # include <fcntl.h>
102 # include <string.h>
103 # include <syscall.h>
104 # include <sys/sysinfo.h>
105 # include <gnu/libc-version.h>
106 # include <sys/ipc.h>
107 # include <sys/shm.h>
108 # include <link.h>
109 # include <stdint.h>
110 # include <inttypes.h>
111 # include <sys/ioctl.h>
112
113 #ifndef _GNU_SOURCE
114 #define _GNU_SOURCE
115 #include <sched.h>
116 #undef _GNU_SOURCE
117 #else
118 #include <sched.h>
119 #endif
120
121 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
122 // getrusage() is prepared to handle the associated failure.
123 #ifndef RUSAGE_THREAD
124 #define RUSAGE_THREAD (1) /* only the calling thread */
125 #endif
126
127 #define MAX_PATH (2 * K)
128
129 #define MAX_SECS 100000000
130
131 // for timer info max values which include all bits
132 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
133
134 enum CoredumpFilterBit {
135 FILE_BACKED_PVT_BIT = 1 << 2,
136 FILE_BACKED_SHARED_BIT = 1 << 3,
137 LARGEPAGES_BIT = 1 << 6,
138 DAX_SHARED_BIT = 1 << 8
139 };
140
141 ////////////////////////////////////////////////////////////////////////////////
142 // global variables
143 julong os::Linux::_physical_memory = 0;
144
145 address os::Linux::_initial_thread_stack_bottom = NULL;
146 uintptr_t os::Linux::_initial_thread_stack_size = 0;
147
148 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
149 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
150 Mutex* os::Linux::_createThread_lock = 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 uint32_t os::Linux::_os_version = 0;
155 const char * os::Linux::_glibc_version = NULL;
156 const char * os::Linux::_libpthread_version = NULL;
157
158 static jlong initial_time_count=0;
159
160 static int clock_tics_per_sec = 100;
161
162 // If the VM might have been created on the primordial thread, we need to resolve the
163 // primordial thread stack bounds and check if the current thread might be the
164 // primordial thread in places. If we know that the primordial thread is never used,
165 // such as when the VM was created by one of the standard java launchers, we can
166 // avoid this
167 static bool suppress_primordial_thread_resolution = false;
168
169 // For diagnostics to print a message once. see run_periodic_checks
170 static sigset_t check_signal_done;
171 static bool check_signals = true;
172
173 // Signal number used to suspend/resume a thread
174
175 // do not use any signal number less than SIGSEGV, see 4355769
176 static int SR_signum = SIGUSR2;
177 sigset_t SR_sigset;
178
179 // utility functions
180
181 static int SR_initialize();
182
183 julong os::available_memory() {
184 return Linux::available_memory();
185 }
186
187 julong os::Linux::available_memory() {
188 // values in struct sysinfo are "unsigned long"
189 struct sysinfo si;
190 julong avail_mem;
191
192 if (OSContainer::is_containerized()) {
193 jlong mem_limit, mem_usage;
194 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
195 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
196 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
197 }
198 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
199 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
200 }
201 if (mem_limit > 0 && mem_usage > 0 ) {
202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
203 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
204 return avail_mem;
205 }
206 }
207
208 sysinfo(&si);
209 avail_mem = (julong)si.freeram * si.mem_unit;
210 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
211 return avail_mem;
212 }
213
214 julong os::physical_memory() {
215 jlong phys_mem = 0;
216 if (OSContainer::is_containerized()) {
217 jlong mem_limit;
218 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
219 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
220 return mem_limit;
221 }
222 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
223 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
224 }
225
226 phys_mem = Linux::physical_memory();
227 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
228 return phys_mem;
229 }
230
231 static uint64_t initial_total_ticks = 0;
232 static uint64_t initial_steal_ticks = 0;
233 static bool has_initial_tick_info = false;
234
235 static void next_line(FILE *f) {
236 int c;
237 do {
238 c = fgetc(f);
239 } while (c != '\n' && c != EOF);
240 }
241
242 bool os::Linux::get_tick_information(CPUPerfTicks* pticks, int which_logical_cpu) {
243 FILE* fh;
244 uint64_t userTicks, niceTicks, systemTicks, idleTicks;
245 // since at least kernel 2.6 : iowait: time waiting for I/O to complete
246 // irq: time servicing interrupts; softirq: time servicing softirqs
247 uint64_t iowTicks = 0, irqTicks = 0, sirqTicks= 0;
248 // steal (since kernel 2.6.11): time spent in other OS when running in a virtualized environment
249 uint64_t stealTicks = 0;
250 // guest (since kernel 2.6.24): time spent running a virtual CPU for guest OS under the
251 // control of the Linux kernel
252 uint64_t guestNiceTicks = 0;
253 int logical_cpu = -1;
254 const int required_tickinfo_count = (which_logical_cpu == -1) ? 4 : 5;
255 int n;
256
257 memset(pticks, 0, sizeof(CPUPerfTicks));
258
259 if ((fh = fopen("/proc/stat", "r")) == NULL) {
260 return false;
261 }
262
263 if (which_logical_cpu == -1) {
264 n = fscanf(fh, "cpu " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
265 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
266 UINT64_FORMAT " " UINT64_FORMAT " ",
267 &userTicks, &niceTicks, &systemTicks, &idleTicks,
268 &iowTicks, &irqTicks, &sirqTicks,
269 &stealTicks, &guestNiceTicks);
270 } else {
271 // Move to next line
272 next_line(fh);
273
274 // find the line for requested cpu faster to just iterate linefeeds?
275 for (int i = 0; i < which_logical_cpu; i++) {
276 next_line(fh);
277 }
278
279 n = fscanf(fh, "cpu%u " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
280 UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " " UINT64_FORMAT " "
281 UINT64_FORMAT " " UINT64_FORMAT " ",
282 &logical_cpu, &userTicks, &niceTicks,
283 &systemTicks, &idleTicks, &iowTicks, &irqTicks, &sirqTicks,
284 &stealTicks, &guestNiceTicks);
285 }
286
287 fclose(fh);
288 if (n < required_tickinfo_count || logical_cpu != which_logical_cpu) {
289 return false;
290 }
291 pticks->used = userTicks + niceTicks;
292 pticks->usedKernel = systemTicks + irqTicks + sirqTicks;
293 pticks->total = userTicks + niceTicks + systemTicks + idleTicks +
294 iowTicks + irqTicks + sirqTicks + stealTicks + guestNiceTicks;
295
296 if (n > required_tickinfo_count + 3) {
297 pticks->steal = stealTicks;
298 pticks->has_steal_ticks = true;
299 } else {
300 pticks->steal = 0;
301 pticks->has_steal_ticks = false;
302 }
303
304 return true;
305 }
306
307 // Return true if user is running as root.
308
309 bool os::have_special_privileges() {
310 static bool init = false;
311 static bool privileges = false;
312 if (!init) {
313 privileges = (getuid() != geteuid()) || (getgid() != getegid());
314 init = true;
315 }
316 return privileges;
317 }
318
319
320 #ifndef SYS_gettid
321 // i386: 224, ia64: 1105, amd64: 186, sparc 143
322 #ifdef __ia64__
323 #define SYS_gettid 1105
324 #else
325 #ifdef __i386__
326 #define SYS_gettid 224
327 #else
328 #ifdef __amd64__
329 #define SYS_gettid 186
330 #else
331 #ifdef __sparc__
332 #define SYS_gettid 143
333 #else
334 #error define gettid for the arch
335 #endif
336 #endif
337 #endif
338 #endif
339 #endif
340
341
342 // pid_t gettid()
343 //
344 // Returns the kernel thread id of the currently running thread. Kernel
345 // thread id is used to access /proc.
346 pid_t os::Linux::gettid() {
347 int rslt = syscall(SYS_gettid);
348 assert(rslt != -1, "must be."); // old linuxthreads implementation?
349 return (pid_t)rslt;
350 }
351
352 // Most versions of linux have a bug where the number of processors are
353 // determined by looking at the /proc file system. In a chroot environment,
354 // the system call returns 1.
355 static bool unsafe_chroot_detected = false;
356 static const char *unstable_chroot_error = "/proc file system not found.\n"
357 "Java may be unstable running multithreaded in a chroot "
358 "environment on Linux when /proc filesystem is not mounted.";
359
360 void os::Linux::initialize_system_info() {
361 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
362 if (processor_count() == 1) {
363 pid_t pid = os::Linux::gettid();
364 char fname[32];
365 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
366 FILE *fp = fopen(fname, "r");
367 if (fp == NULL) {
368 unsafe_chroot_detected = true;
369 } else {
370 fclose(fp);
371 }
372 }
373 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
374 assert(processor_count() > 0, "linux error");
375 }
376
377 void os::init_system_properties_values() {
378 // The next steps are taken in the product version:
379 //
380 // Obtain the JAVA_HOME value from the location of libjvm.so.
381 // This library should be located at:
382 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
383 //
384 // If "/jre/lib/" appears at the right place in the path, then we
385 // assume libjvm.so is installed in a JDK and we use this path.
386 //
387 // Otherwise exit with message: "Could not create the Java virtual machine."
388 //
389 // The following extra steps are taken in the debugging version:
390 //
391 // If "/jre/lib/" does NOT appear at the right place in the path
392 // instead of exit check for $JAVA_HOME environment variable.
393 //
394 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
395 // then we append a fake suffix "hotspot/libjvm.so" to this path so
396 // it looks like libjvm.so is installed there
397 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
398 //
399 // Otherwise exit.
400 //
401 // Important note: if the location of libjvm.so changes this
402 // code needs to be changed accordingly.
403
404 // See ld(1):
405 // The linker uses the following search paths to locate required
406 // shared libraries:
407 // 1: ...
408 // ...
409 // 7: The default directories, normally /lib and /usr/lib.
410 #ifndef OVERRIDE_LIBPATH
411 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
412 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
413 #else
414 #define DEFAULT_LIBPATH "/lib:/usr/lib"
415 #endif
416 #else
417 #define DEFAULT_LIBPATH OVERRIDE_LIBPATH
418 #endif
419
420 // Base path of extensions installed on the system.
421 #define SYS_EXT_DIR "/usr/java/packages"
422 #define EXTENSIONS_DIR "/lib/ext"
423
424 // Buffer that fits several sprintfs.
425 // Note that the space for the colon and the trailing null are provided
426 // by the nulls included by the sizeof operator.
427 const size_t bufsize =
428 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
429 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
430 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
431
432 // sysclasspath, java_home, dll_dir
433 {
434 char *pslash;
435 os::jvm_path(buf, bufsize);
436
437 // Found the full path to libjvm.so.
438 // Now cut the path to <java_home>/jre if we can.
439 pslash = strrchr(buf, '/');
440 if (pslash != NULL) {
441 *pslash = '\0'; // Get rid of /libjvm.so.
442 }
443 pslash = strrchr(buf, '/');
444 if (pslash != NULL) {
445 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
446 }
447 Arguments::set_dll_dir(buf);
448
449 if (pslash != NULL) {
450 pslash = strrchr(buf, '/');
451 if (pslash != NULL) {
452 *pslash = '\0'; // Get rid of /lib.
453 }
454 }
455 Arguments::set_java_home(buf);
456 if (!set_boot_path('/', ':')) {
457 vm_exit_during_initialization("Failed setting boot class path.", NULL);
458 }
459 }
460
461 // Where to look for native libraries.
462 //
463 // Note: Due to a legacy implementation, most of the library path
464 // is set in the launcher. This was to accomodate linking restrictions
465 // on legacy Linux implementations (which are no longer supported).
466 // Eventually, all the library path setting will be done here.
467 //
468 // However, to prevent the proliferation of improperly built native
469 // libraries, the new path component /usr/java/packages is added here.
470 // Eventually, all the library path setting will be done here.
471 {
472 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
473 // should always exist (until the legacy problem cited above is
474 // addressed).
475 const char *v = ::getenv("LD_LIBRARY_PATH");
476 const char *v_colon = ":";
477 if (v == NULL) { v = ""; v_colon = ""; }
478 // That's +1 for the colon and +1 for the trailing '\0'.
479 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
480 strlen(v) + 1 +
481 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
482 mtInternal);
483 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
484 Arguments::set_library_path(ld_library_path);
485 FREE_C_HEAP_ARRAY(char, ld_library_path);
486 }
487
488 // Extensions directories.
489 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
490 Arguments::set_ext_dirs(buf);
491
492 FREE_C_HEAP_ARRAY(char, buf);
493
494 #undef DEFAULT_LIBPATH
495 #undef SYS_EXT_DIR
496 #undef EXTENSIONS_DIR
497 }
498
499 ////////////////////////////////////////////////////////////////////////////////
500 // breakpoint support
501
502 void os::breakpoint() {
503 BREAKPOINT;
504 }
505
506 extern "C" void breakpoint() {
507 // use debugger to set breakpoint here
508 }
509
510 ////////////////////////////////////////////////////////////////////////////////
511 // signal support
512
513 debug_only(static bool signal_sets_initialized = false);
514 static sigset_t unblocked_sigs, vm_sigs;
515
516 void os::Linux::signal_sets_init() {
517 // Should also have an assertion stating we are still single-threaded.
518 assert(!signal_sets_initialized, "Already initialized");
519 // Fill in signals that are necessarily unblocked for all threads in
520 // the VM. Currently, we unblock the following signals:
521 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
522 // by -Xrs (=ReduceSignalUsage));
523 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
524 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
525 // the dispositions or masks wrt these signals.
526 // Programs embedding the VM that want to use the above signals for their
527 // own purposes must, at this time, use the "-Xrs" option to prevent
528 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
529 // (See bug 4345157, and other related bugs).
530 // In reality, though, unblocking these signals is really a nop, since
531 // these signals are not blocked by default.
532 sigemptyset(&unblocked_sigs);
533 sigaddset(&unblocked_sigs, SIGILL);
534 sigaddset(&unblocked_sigs, SIGSEGV);
535 sigaddset(&unblocked_sigs, SIGBUS);
536 sigaddset(&unblocked_sigs, SIGFPE);
537 #if defined(PPC64)
538 sigaddset(&unblocked_sigs, SIGTRAP);
539 #endif
540 sigaddset(&unblocked_sigs, SR_signum);
541
542 if (!ReduceSignalUsage) {
543 if (!os::Posix::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
544 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
545 }
546 if (!os::Posix::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
547 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
548 }
549 if (!os::Posix::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
550 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
551 }
552 }
553 // Fill in signals that are blocked by all but the VM thread.
554 sigemptyset(&vm_sigs);
555 if (!ReduceSignalUsage) {
556 sigaddset(&vm_sigs, BREAK_SIGNAL);
557 }
558 debug_only(signal_sets_initialized = true);
559
560 }
561
562 // These are signals that are unblocked while a thread is running Java.
563 // (For some reason, they get blocked by default.)
564 sigset_t* os::Linux::unblocked_signals() {
565 assert(signal_sets_initialized, "Not initialized");
566 return &unblocked_sigs;
567 }
568
569 // These are the signals that are blocked while a (non-VM) thread is
570 // running Java. Only the VM thread handles these signals.
571 sigset_t* os::Linux::vm_signals() {
572 assert(signal_sets_initialized, "Not initialized");
573 return &vm_sigs;
574 }
575
576 void os::Linux::hotspot_sigmask(Thread* thread) {
577
578 //Save caller's signal mask before setting VM signal mask
579 sigset_t caller_sigmask;
580 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
581
582 OSThread* osthread = thread->osthread();
583 osthread->set_caller_sigmask(caller_sigmask);
584
585 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
586
587 if (!ReduceSignalUsage) {
588 if (thread->is_VM_thread()) {
589 // Only the VM thread handles BREAK_SIGNAL ...
590 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
591 } else {
592 // ... all other threads block BREAK_SIGNAL
593 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
594 }
595 }
596 }
597
598 //////////////////////////////////////////////////////////////////////////////
599 // detecting pthread library
600
601 void os::Linux::libpthread_init() {
602 // Save glibc and pthread version strings.
603 #if !defined(_CS_GNU_LIBC_VERSION) || \
604 !defined(_CS_GNU_LIBPTHREAD_VERSION)
605 #error "glibc too old (< 2.3.2)"
606 #endif
607
608 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
609 assert(n > 0, "cannot retrieve glibc version");
610 char *str = (char *)malloc(n, mtInternal);
611 confstr(_CS_GNU_LIBC_VERSION, str, n);
612 os::Linux::set_glibc_version(str);
613
614 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
615 assert(n > 0, "cannot retrieve pthread version");
616 str = (char *)malloc(n, mtInternal);
617 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
618 os::Linux::set_libpthread_version(str);
619 }
620
621 /////////////////////////////////////////////////////////////////////////////
622 // thread stack expansion
623
624 // os::Linux::manually_expand_stack() takes care of expanding the thread
625 // stack. Note that this is normally not needed: pthread stacks allocate
626 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
627 // committed. Therefore it is not necessary to expand the stack manually.
628 //
629 // Manually expanding the stack was historically needed on LinuxThreads
630 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
631 // it is kept to deal with very rare corner cases:
632 //
633 // For one, user may run the VM on an own implementation of threads
634 // whose stacks are - like the old LinuxThreads - implemented using
635 // mmap(MAP_GROWSDOWN).
636 //
637 // Also, this coding may be needed if the VM is running on the primordial
638 // thread. Normally we avoid running on the primordial thread; however,
639 // user may still invoke the VM on the primordial thread.
640 //
641 // The following historical comment describes the details about running
642 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
643
644
645 // Force Linux kernel to expand current thread stack. If "bottom" is close
646 // to the stack guard, caller should block all signals.
647 //
648 // MAP_GROWSDOWN:
649 // A special mmap() flag that is used to implement thread stacks. It tells
650 // kernel that the memory region should extend downwards when needed. This
651 // allows early versions of LinuxThreads to only mmap the first few pages
652 // when creating a new thread. Linux kernel will automatically expand thread
653 // stack as needed (on page faults).
654 //
655 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
656 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
657 // region, it's hard to tell if the fault is due to a legitimate stack
658 // access or because of reading/writing non-exist memory (e.g. buffer
659 // overrun). As a rule, if the fault happens below current stack pointer,
660 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
661 // application (see Linux kernel fault.c).
662 //
663 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
664 // stack overflow detection.
665 //
666 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
667 // not use MAP_GROWSDOWN.
668 //
669 // To get around the problem and allow stack banging on Linux, we need to
670 // manually expand thread stack after receiving the SIGSEGV.
671 //
672 // There are two ways to expand thread stack to address "bottom", we used
673 // both of them in JVM before 1.5:
674 // 1. adjust stack pointer first so that it is below "bottom", and then
675 // touch "bottom"
676 // 2. mmap() the page in question
677 //
678 // Now alternate signal stack is gone, it's harder to use 2. For instance,
679 // if current sp is already near the lower end of page 101, and we need to
680 // call mmap() to map page 100, it is possible that part of the mmap() frame
681 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
682 // That will destroy the mmap() frame and cause VM to crash.
683 //
684 // The following code works by adjusting sp first, then accessing the "bottom"
685 // page to force a page fault. Linux kernel will then automatically expand the
686 // stack mapping.
687 //
688 // _expand_stack_to() assumes its frame size is less than page size, which
689 // should always be true if the function is not inlined.
690
691 static void NOINLINE _expand_stack_to(address bottom) {
692 address sp;
693 size_t size;
694 volatile char *p;
695
696 // Adjust bottom to point to the largest address within the same page, it
697 // gives us a one-page buffer if alloca() allocates slightly more memory.
698 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
699 bottom += os::Linux::page_size() - 1;
700
701 // sp might be slightly above current stack pointer; if that's the case, we
702 // will alloca() a little more space than necessary, which is OK. Don't use
703 // os::current_stack_pointer(), as its result can be slightly below current
704 // stack pointer, causing us to not alloca enough to reach "bottom".
705 sp = (address)&sp;
706
707 if (sp > bottom) {
708 size = sp - bottom;
709 p = (volatile char *)alloca(size);
710 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
711 p[0] = '\0';
712 }
713 }
714
715 void os::Linux::expand_stack_to(address bottom) {
716 _expand_stack_to(bottom);
717 }
718
719 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
720 assert(t!=NULL, "just checking");
721 assert(t->osthread()->expanding_stack(), "expand should be set");
722 assert(t->stack_base() != NULL, "stack_base was not initialized");
723
724 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
725 sigset_t mask_all, old_sigset;
726 sigfillset(&mask_all);
727 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
728 _expand_stack_to(addr);
729 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
730 return true;
731 }
732 return false;
733 }
734
735 //////////////////////////////////////////////////////////////////////////////
736 // create new thread
737
738 // Thread start routine for all newly created threads
739 static void *thread_native_entry(Thread *thread) {
740
741 thread->record_stack_base_and_size();
742
743 // Try to randomize the cache line index of hot stack frames.
744 // This helps when threads of the same stack traces evict each other's
745 // cache lines. The threads can be either from the same JVM instance, or
746 // from different JVM instances. The benefit is especially true for
747 // processors with hyperthreading technology.
748 static int counter = 0;
749 int pid = os::current_process_id();
750 alloca(((pid ^ counter++) & 7) * 128);
751
752 thread->initialize_thread_current();
753
754 OSThread* osthread = thread->osthread();
755 Monitor* sync = osthread->startThread_lock();
756
757 osthread->set_thread_id(os::current_thread_id());
758
759 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
760 os::current_thread_id(), (uintx) pthread_self());
761
762 if (UseNUMA) {
763 int lgrp_id = os::numa_get_group_id();
764 if (lgrp_id != -1) {
765 thread->set_lgrp_id(lgrp_id);
766 }
767 }
768 // initialize signal mask for this thread
769 os::Linux::hotspot_sigmask(thread);
770
771 // initialize floating point control register
772 os::Linux::init_thread_fpu_state();
773
774 // handshaking with parent thread
775 {
776 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
777
778 // notify parent thread
779 osthread->set_state(INITIALIZED);
780 sync->notify_all();
781
782 // wait until os::start_thread()
783 while (osthread->get_state() == INITIALIZED) {
784 sync->wait(Mutex::_no_safepoint_check_flag);
785 }
786 }
787
788 assert(osthread->pthread_id() != 0, "pthread_id was not set as expected");
789
790 // call one more level start routine
791 thread->call_run();
792
793 // Note: at this point the thread object may already have deleted itself.
794 // Prevent dereferencing it from here on out.
795 thread = NULL;
796
797 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
798 os::current_thread_id(), (uintx) pthread_self());
799
800 return 0;
801 }
802
803 bool os::create_thread(Thread* thread, ThreadType thr_type,
804 size_t req_stack_size) {
805 assert(thread->osthread() == NULL, "caller responsible");
806
807 // Allocate the OSThread object
808 OSThread* osthread = new OSThread(NULL, NULL);
809 if (osthread == NULL) {
810 return false;
811 }
812
813 // set the correct thread state
814 osthread->set_thread_type(thr_type);
815
816 // Initial state is ALLOCATED but not INITIALIZED
817 osthread->set_state(ALLOCATED);
818
819 thread->set_osthread(osthread);
820
821 // init thread attributes
822 pthread_attr_t attr;
823 pthread_attr_init(&attr);
824 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
825
826 // Calculate stack size if it's not specified by caller.
827 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
828 // In the Linux NPTL pthread implementation the guard size mechanism
829 // is not implemented properly. The posix standard requires adding
830 // the size of the guard pages to the stack size, instead Linux
831 // takes the space out of 'stacksize'. Thus we adapt the requested
832 // stack_size by the size of the guard pages to mimick proper
833 // behaviour. However, be careful not to end up with a size
834 // of zero due to overflow. Don't add the guard page in that case.
835 size_t guard_size = os::Linux::default_guard_size(thr_type);
836 if (stack_size <= SIZE_MAX - guard_size) {
837 stack_size += guard_size;
838 }
839 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
840
841 int status = pthread_attr_setstacksize(&attr, stack_size);
842 assert_status(status == 0, status, "pthread_attr_setstacksize");
843
844 // Configure glibc guard page.
845 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
846
847 ThreadState state;
848
849 {
850 pthread_t tid;
851 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
852
853 char buf[64];
854 if (ret == 0) {
855 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
856 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
857 } else {
858 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
859 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
860 // Log some OS information which might explain why creating the thread failed.
861 log_info(os, thread)("Number of threads approx. running in the VM: %d", Threads::number_of_threads());
862 LogStream st(Log(os, thread)::info());
863 os::Posix::print_rlimit_info(&st);
864 os::print_memory_info(&st);
865 os::Linux::print_proc_sys_info(&st);
866 os::Linux::print_container_info(&st);
867 }
868
869 pthread_attr_destroy(&attr);
870
871 if (ret != 0) {
872 // Need to clean up stuff we've allocated so far
873 thread->set_osthread(NULL);
874 delete osthread;
875 return false;
876 }
877
878 // Store pthread info into the OSThread
879 osthread->set_pthread_id(tid);
880
881 // Wait until child thread is either initialized or aborted
882 {
883 Monitor* sync_with_child = osthread->startThread_lock();
884 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
885 while ((state = osthread->get_state()) == ALLOCATED) {
886 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
887 }
888 }
889 }
890
891 // Aborted due to thread limit being reached
892 if (state == ZOMBIE) {
893 thread->set_osthread(NULL);
894 delete osthread;
895 return false;
896 }
897
898 // The thread is returned suspended (in state INITIALIZED),
899 // and is started higher up in the call chain
900 assert(state == INITIALIZED, "race condition");
901 return true;
902 }
903
904 /////////////////////////////////////////////////////////////////////////////
905 // attach existing thread
906
907 // bootstrap the main thread
908 bool os::create_main_thread(JavaThread* thread) {
909 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
910 return create_attached_thread(thread);
911 }
912
913 bool os::create_attached_thread(JavaThread* thread) {
914 #ifdef ASSERT
915 thread->verify_not_published();
916 #endif
917
918 // Allocate the OSThread object
919 OSThread* osthread = new OSThread(NULL, NULL);
920
921 if (osthread == NULL) {
922 return false;
923 }
924
925 // Store pthread info into the OSThread
926 osthread->set_thread_id(os::Linux::gettid());
927 osthread->set_pthread_id(::pthread_self());
928
929 // initialize floating point control register
930 os::Linux::init_thread_fpu_state();
931
932 // Initial thread state is RUNNABLE
933 osthread->set_state(RUNNABLE);
934
935 thread->set_osthread(osthread);
936
937 if (UseNUMA) {
938 int lgrp_id = os::numa_get_group_id();
939 if (lgrp_id != -1) {
940 thread->set_lgrp_id(lgrp_id);
941 }
942 }
943
944 if (os::is_primordial_thread()) {
945 // If current thread is primordial thread, its stack is mapped on demand,
946 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
947 // the entire stack region to avoid SEGV in stack banging.
948 // It is also useful to get around the heap-stack-gap problem on SuSE
949 // kernel (see 4821821 for details). We first expand stack to the top
950 // of yellow zone, then enable stack yellow zone (order is significant,
951 // enabling yellow zone first will crash JVM on SuSE Linux), so there
952 // is no gap between the last two virtual memory regions.
953
954 JavaThread *jt = (JavaThread *)thread;
955 address addr = jt->stack_reserved_zone_base();
956 assert(addr != NULL, "initialization problem?");
957 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
958
959 osthread->set_expanding_stack();
960 os::Linux::manually_expand_stack(jt, addr);
961 osthread->clear_expanding_stack();
962 }
963
964 // initialize signal mask for this thread
965 // and save the caller's signal mask
966 os::Linux::hotspot_sigmask(thread);
967
968 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
969 os::current_thread_id(), (uintx) pthread_self());
970
971 return true;
972 }
973
974 void os::pd_start_thread(Thread* thread) {
975 OSThread * osthread = thread->osthread();
976 assert(osthread->get_state() != INITIALIZED, "just checking");
977 Monitor* sync_with_child = osthread->startThread_lock();
978 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
979 sync_with_child->notify();
980 }
981
982 // Free Linux resources related to the OSThread
983 void os::free_thread(OSThread* osthread) {
984 assert(osthread != NULL, "osthread not set");
985
986 // We are told to free resources of the argument thread,
987 // but we can only really operate on the current thread.
988 assert(Thread::current()->osthread() == osthread,
989 "os::free_thread but not current thread");
990
991 #ifdef ASSERT
992 sigset_t current;
993 sigemptyset(¤t);
994 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
995 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
996 #endif
997
998 // Restore caller's signal mask
999 sigset_t sigmask = osthread->caller_sigmask();
1000 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1001
1002 delete osthread;
1003 }
1004
1005 //////////////////////////////////////////////////////////////////////////////
1006 // primordial thread
1007
1008 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1009 bool os::is_primordial_thread(void) {
1010 if (suppress_primordial_thread_resolution) {
1011 return false;
1012 }
1013 char dummy;
1014 // If called before init complete, thread stack bottom will be null.
1015 // Can be called if fatal error occurs before initialization.
1016 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1017 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1018 os::Linux::initial_thread_stack_size() != 0,
1019 "os::init did not locate primordial thread's stack region");
1020 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1021 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1022 os::Linux::initial_thread_stack_size()) {
1023 return true;
1024 } else {
1025 return false;
1026 }
1027 }
1028
1029 // Find the virtual memory area that contains addr
1030 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1031 FILE *fp = fopen("/proc/self/maps", "r");
1032 if (fp) {
1033 address low, high;
1034 while (!feof(fp)) {
1035 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1036 if (low <= addr && addr < high) {
1037 if (vma_low) *vma_low = low;
1038 if (vma_high) *vma_high = high;
1039 fclose(fp);
1040 return true;
1041 }
1042 }
1043 for (;;) {
1044 int ch = fgetc(fp);
1045 if (ch == EOF || ch == (int)'\n') break;
1046 }
1047 }
1048 fclose(fp);
1049 }
1050 return false;
1051 }
1052
1053 // Locate primordial thread stack. This special handling of primordial thread stack
1054 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1055 // bogus value for the primordial process thread. While the launcher has created
1056 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1057 // JNI invocation API from a primordial thread.
1058 void os::Linux::capture_initial_stack(size_t max_size) {
1059
1060 // max_size is either 0 (which means accept OS default for thread stacks) or
1061 // a user-specified value known to be at least the minimum needed. If we
1062 // are actually on the primordial thread we can make it appear that we have a
1063 // smaller max_size stack by inserting the guard pages at that location. But we
1064 // cannot do anything to emulate a larger stack than what has been provided by
1065 // the OS or threading library. In fact if we try to use a stack greater than
1066 // what is set by rlimit then we will crash the hosting process.
1067
1068 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1069 // If this is "unlimited" then it will be a huge value.
1070 struct rlimit rlim;
1071 getrlimit(RLIMIT_STACK, &rlim);
1072 size_t stack_size = rlim.rlim_cur;
1073
1074 // 6308388: a bug in ld.so will relocate its own .data section to the
1075 // lower end of primordial stack; reduce ulimit -s value a little bit
1076 // so we won't install guard page on ld.so's data section.
1077 // But ensure we don't underflow the stack size - allow 1 page spare
1078 if (stack_size >= (size_t)(3 * page_size())) {
1079 stack_size -= 2 * page_size();
1080 }
1081
1082 // Try to figure out where the stack base (top) is. This is harder.
1083 //
1084 // When an application is started, glibc saves the initial stack pointer in
1085 // a global variable "__libc_stack_end", which is then used by system
1086 // libraries. __libc_stack_end should be pretty close to stack top. The
1087 // variable is available since the very early days. However, because it is
1088 // a private interface, it could disappear in the future.
1089 //
1090 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1091 // to __libc_stack_end, it is very close to stack top, but isn't the real
1092 // stack top. Note that /proc may not exist if VM is running as a chroot
1093 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1094 // /proc/<pid>/stat could change in the future (though unlikely).
1095 //
1096 // We try __libc_stack_end first. If that doesn't work, look for
1097 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1098 // as a hint, which should work well in most cases.
1099
1100 uintptr_t stack_start;
1101
1102 // try __libc_stack_end first
1103 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1104 if (p && *p) {
1105 stack_start = *p;
1106 } else {
1107 // see if we can get the start_stack field from /proc/self/stat
1108 FILE *fp;
1109 int pid;
1110 char state;
1111 int ppid;
1112 int pgrp;
1113 int session;
1114 int nr;
1115 int tpgrp;
1116 unsigned long flags;
1117 unsigned long minflt;
1118 unsigned long cminflt;
1119 unsigned long majflt;
1120 unsigned long cmajflt;
1121 unsigned long utime;
1122 unsigned long stime;
1123 long cutime;
1124 long cstime;
1125 long prio;
1126 long nice;
1127 long junk;
1128 long it_real;
1129 uintptr_t start;
1130 uintptr_t vsize;
1131 intptr_t rss;
1132 uintptr_t rsslim;
1133 uintptr_t scodes;
1134 uintptr_t ecode;
1135 int i;
1136
1137 // Figure what the primordial thread stack base is. Code is inspired
1138 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1139 // followed by command name surrounded by parentheses, state, etc.
1140 char stat[2048];
1141 int statlen;
1142
1143 fp = fopen("/proc/self/stat", "r");
1144 if (fp) {
1145 statlen = fread(stat, 1, 2047, fp);
1146 stat[statlen] = '\0';
1147 fclose(fp);
1148
1149 // Skip pid and the command string. Note that we could be dealing with
1150 // weird command names, e.g. user could decide to rename java launcher
1151 // to "java 1.4.2 :)", then the stat file would look like
1152 // 1234 (java 1.4.2 :)) R ... ...
1153 // We don't really need to know the command string, just find the last
1154 // occurrence of ")" and then start parsing from there. See bug 4726580.
1155 char * s = strrchr(stat, ')');
1156
1157 i = 0;
1158 if (s) {
1159 // Skip blank chars
1160 do { s++; } while (s && isspace(*s));
1161
1162 #define _UFM UINTX_FORMAT
1163 #define _DFM INTX_FORMAT
1164
1165 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1166 // 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
1167 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,
1168 &state, // 3 %c
1169 &ppid, // 4 %d
1170 &pgrp, // 5 %d
1171 &session, // 6 %d
1172 &nr, // 7 %d
1173 &tpgrp, // 8 %d
1174 &flags, // 9 %lu
1175 &minflt, // 10 %lu
1176 &cminflt, // 11 %lu
1177 &majflt, // 12 %lu
1178 &cmajflt, // 13 %lu
1179 &utime, // 14 %lu
1180 &stime, // 15 %lu
1181 &cutime, // 16 %ld
1182 &cstime, // 17 %ld
1183 &prio, // 18 %ld
1184 &nice, // 19 %ld
1185 &junk, // 20 %ld
1186 &it_real, // 21 %ld
1187 &start, // 22 UINTX_FORMAT
1188 &vsize, // 23 UINTX_FORMAT
1189 &rss, // 24 INTX_FORMAT
1190 &rsslim, // 25 UINTX_FORMAT
1191 &scodes, // 26 UINTX_FORMAT
1192 &ecode, // 27 UINTX_FORMAT
1193 &stack_start); // 28 UINTX_FORMAT
1194 }
1195
1196 #undef _UFM
1197 #undef _DFM
1198
1199 if (i != 28 - 2) {
1200 assert(false, "Bad conversion from /proc/self/stat");
1201 // product mode - assume we are the primordial thread, good luck in the
1202 // embedded case.
1203 warning("Can't detect primordial thread stack location - bad conversion");
1204 stack_start = (uintptr_t) &rlim;
1205 }
1206 } else {
1207 // For some reason we can't open /proc/self/stat (for example, running on
1208 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1209 // most cases, so don't abort:
1210 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1211 stack_start = (uintptr_t) &rlim;
1212 }
1213 }
1214
1215 // Now we have a pointer (stack_start) very close to the stack top, the
1216 // next thing to do is to figure out the exact location of stack top. We
1217 // can find out the virtual memory area that contains stack_start by
1218 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1219 // and its upper limit is the real stack top. (again, this would fail if
1220 // running inside chroot, because /proc may not exist.)
1221
1222 uintptr_t stack_top;
1223 address low, high;
1224 if (find_vma((address)stack_start, &low, &high)) {
1225 // success, "high" is the true stack top. (ignore "low", because initial
1226 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1227 stack_top = (uintptr_t)high;
1228 } else {
1229 // failed, likely because /proc/self/maps does not exist
1230 warning("Can't detect primordial thread stack location - find_vma failed");
1231 // best effort: stack_start is normally within a few pages below the real
1232 // stack top, use it as stack top, and reduce stack size so we won't put
1233 // guard page outside stack.
1234 stack_top = stack_start;
1235 stack_size -= 16 * page_size();
1236 }
1237
1238 // stack_top could be partially down the page so align it
1239 stack_top = align_up(stack_top, page_size());
1240
1241 // Allowed stack value is minimum of max_size and what we derived from rlimit
1242 if (max_size > 0) {
1243 _initial_thread_stack_size = MIN2(max_size, stack_size);
1244 } else {
1245 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1246 // clamp it at 8MB as we do on Solaris
1247 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1248 }
1249 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1250 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1251
1252 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1253
1254 if (log_is_enabled(Info, os, thread)) {
1255 // See if we seem to be on primordial process thread
1256 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1257 uintptr_t(&rlim) < stack_top;
1258
1259 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1260 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1261 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1262 stack_top, intptr_t(_initial_thread_stack_bottom));
1263 }
1264 }
1265
1266 ////////////////////////////////////////////////////////////////////////////////
1267 // time support
1268
1269 #ifndef SUPPORTS_CLOCK_MONOTONIC
1270 #error "Build platform doesn't support clock_gettime and related functionality"
1271 #endif
1272
1273 // Time since start-up in seconds to a fine granularity.
1274 // Used by VMSelfDestructTimer and the MemProfiler.
1275 double os::elapsedTime() {
1276
1277 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1278 }
1279
1280 jlong os::elapsed_counter() {
1281 return javaTimeNanos() - initial_time_count;
1282 }
1283
1284 jlong os::elapsed_frequency() {
1285 return NANOSECS_PER_SEC; // nanosecond resolution
1286 }
1287
1288 bool os::supports_vtime() { return true; }
1289 bool os::enable_vtime() { return false; }
1290 bool os::vtime_enabled() { return false; }
1291
1292 double os::elapsedVTime() {
1293 struct rusage usage;
1294 int retval = getrusage(RUSAGE_THREAD, &usage);
1295 if (retval == 0) {
1296 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);
1297 } else {
1298 // better than nothing, but not much
1299 return elapsedTime();
1300 }
1301 }
1302
1303 jlong os::javaTimeMillis() {
1304 timeval time;
1305 int status = gettimeofday(&time, NULL);
1306 assert(status != -1, "linux error");
1307 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1308 }
1309
1310 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1311 timeval time;
1312 int status = gettimeofday(&time, NULL);
1313 assert(status != -1, "linux error");
1314 seconds = jlong(time.tv_sec);
1315 nanos = jlong(time.tv_usec) * 1000;
1316 }
1317
1318 void os::Linux::fast_thread_clock_init() {
1319 if (!UseLinuxPosixThreadCPUClocks) {
1320 return;
1321 }
1322 clockid_t clockid;
1323 struct timespec tp;
1324 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1325 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1326
1327 // Switch to using fast clocks for thread cpu time if
1328 // the clock_getres() returns 0 error code.
1329 // Note, that some kernels may support the current thread
1330 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1331 // returned by the pthread_getcpuclockid().
1332 // If the fast Posix clocks are supported then the clock_getres()
1333 // must return at least tp.tv_sec == 0 which means a resolution
1334 // better than 1 sec. This is extra check for reliability.
1335
1336 if (pthread_getcpuclockid_func &&
1337 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1338 os::Posix::clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1339 _supports_fast_thread_cpu_time = true;
1340 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1341 }
1342 }
1343
1344 jlong os::javaTimeNanos() {
1345 if (os::supports_monotonic_clock()) {
1346 struct timespec tp;
1347 int status = os::Posix::clock_gettime(CLOCK_MONOTONIC, &tp);
1348 assert(status == 0, "gettime error");
1349 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1350 return result;
1351 } else {
1352 timeval time;
1353 int status = gettimeofday(&time, NULL);
1354 assert(status != -1, "linux error");
1355 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1356 return 1000 * usecs;
1357 }
1358 }
1359
1360 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1361 if (os::supports_monotonic_clock()) {
1362 info_ptr->max_value = ALL_64_BITS;
1363
1364 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1365 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1366 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1367 } else {
1368 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1369 info_ptr->max_value = ALL_64_BITS;
1370
1371 // gettimeofday is a real time clock so it skips
1372 info_ptr->may_skip_backward = true;
1373 info_ptr->may_skip_forward = true;
1374 }
1375
1376 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1377 }
1378
1379 // Return the real, user, and system times in seconds from an
1380 // arbitrary fixed point in the past.
1381 bool os::getTimesSecs(double* process_real_time,
1382 double* process_user_time,
1383 double* process_system_time) {
1384 struct tms ticks;
1385 clock_t real_ticks = times(&ticks);
1386
1387 if (real_ticks == (clock_t) (-1)) {
1388 return false;
1389 } else {
1390 double ticks_per_second = (double) clock_tics_per_sec;
1391 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1392 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1393 *process_real_time = ((double) real_ticks) / ticks_per_second;
1394
1395 return true;
1396 }
1397 }
1398
1399
1400 char * os::local_time_string(char *buf, size_t buflen) {
1401 struct tm t;
1402 time_t long_time;
1403 time(&long_time);
1404 localtime_r(&long_time, &t);
1405 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1406 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1407 t.tm_hour, t.tm_min, t.tm_sec);
1408 return buf;
1409 }
1410
1411 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1412 return localtime_r(clock, res);
1413 }
1414
1415 ////////////////////////////////////////////////////////////////////////////////
1416 // runtime exit support
1417
1418 // Note: os::shutdown() might be called very early during initialization, or
1419 // called from signal handler. Before adding something to os::shutdown(), make
1420 // sure it is async-safe and can handle partially initialized VM.
1421 void os::shutdown() {
1422
1423 // allow PerfMemory to attempt cleanup of any persistent resources
1424 perfMemory_exit();
1425
1426 // needs to remove object in file system
1427 AttachListener::abort();
1428
1429 // flush buffered output, finish log files
1430 ostream_abort();
1431
1432 // Check for abort hook
1433 abort_hook_t abort_hook = Arguments::abort_hook();
1434 if (abort_hook != NULL) {
1435 abort_hook();
1436 }
1437
1438 }
1439
1440 // Note: os::abort() might be called very early during initialization, or
1441 // called from signal handler. Before adding something to os::abort(), make
1442 // sure it is async-safe and can handle partially initialized VM.
1443 void os::abort(bool dump_core, void* siginfo, const void* context) {
1444 os::shutdown();
1445 if (dump_core) {
1446 if (DumpPrivateMappingsInCore) {
1447 ClassLoader::close_jrt_image();
1448 }
1449 #ifndef PRODUCT
1450 fdStream out(defaultStream::output_fd());
1451 out.print_raw("Current thread is ");
1452 char buf[16];
1453 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1454 out.print_raw_cr(buf);
1455 out.print_raw_cr("Dumping core ...");
1456 #endif
1457 ::abort(); // dump core
1458 }
1459
1460 ::exit(1);
1461 }
1462
1463 // Die immediately, no exit hook, no abort hook, no cleanup.
1464 void os::die() {
1465 ::abort();
1466 }
1467
1468 // thread_id is kernel thread id (similar to Solaris LWP id)
1469 intx os::current_thread_id() { return os::Linux::gettid(); }
1470 int os::current_process_id() {
1471 return ::getpid();
1472 }
1473
1474 // DLL functions
1475
1476 const char* os::dll_file_extension() { return ".so"; }
1477
1478 // This must be hard coded because it's the system's temporary
1479 // directory not the java application's temp directory, ala java.io.tmpdir.
1480 const char* os::get_temp_directory() { return "/tmp"; }
1481
1482 static bool file_exists(const char* filename) {
1483 struct stat statbuf;
1484 if (filename == NULL || strlen(filename) == 0) {
1485 return false;
1486 }
1487 return os::stat(filename, &statbuf) == 0;
1488 }
1489
1490 // check if addr is inside libjvm.so
1491 bool os::address_is_in_vm(address addr) {
1492 static address libjvm_base_addr;
1493 Dl_info dlinfo;
1494
1495 if (libjvm_base_addr == NULL) {
1496 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1497 libjvm_base_addr = (address)dlinfo.dli_fbase;
1498 }
1499 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1500 }
1501
1502 if (dladdr((void *)addr, &dlinfo) != 0) {
1503 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1504 }
1505
1506 return false;
1507 }
1508
1509 bool os::dll_address_to_function_name(address addr, char *buf,
1510 int buflen, int *offset,
1511 bool demangle) {
1512 // buf is not optional, but offset is optional
1513 assert(buf != NULL, "sanity check");
1514
1515 Dl_info dlinfo;
1516
1517 if (dladdr((void*)addr, &dlinfo) != 0) {
1518 // see if we have a matching symbol
1519 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1520 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1521 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1522 }
1523 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1524 return true;
1525 }
1526 // no matching symbol so try for just file info
1527 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1528 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1529 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1530 return true;
1531 }
1532 }
1533 }
1534
1535 buf[0] = '\0';
1536 if (offset != NULL) *offset = -1;
1537 return false;
1538 }
1539
1540 struct _address_to_library_name {
1541 address addr; // input : memory address
1542 size_t buflen; // size of fname
1543 char* fname; // output: library name
1544 address base; // library base addr
1545 };
1546
1547 static int address_to_library_name_callback(struct dl_phdr_info *info,
1548 size_t size, void *data) {
1549 int i;
1550 bool found = false;
1551 address libbase = NULL;
1552 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1553
1554 // iterate through all loadable segments
1555 for (i = 0; i < info->dlpi_phnum; i++) {
1556 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1557 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1558 // base address of a library is the lowest address of its loaded
1559 // segments.
1560 if (libbase == NULL || libbase > segbase) {
1561 libbase = segbase;
1562 }
1563 // see if 'addr' is within current segment
1564 if (segbase <= d->addr &&
1565 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1566 found = true;
1567 }
1568 }
1569 }
1570
1571 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1572 // so dll_address_to_library_name() can fall through to use dladdr() which
1573 // can figure out executable name from argv[0].
1574 if (found && info->dlpi_name && info->dlpi_name[0]) {
1575 d->base = libbase;
1576 if (d->fname) {
1577 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1578 }
1579 return 1;
1580 }
1581 return 0;
1582 }
1583
1584 bool os::dll_address_to_library_name(address addr, char* buf,
1585 int buflen, int* offset) {
1586 // buf is not optional, but offset is optional
1587 assert(buf != NULL, "sanity check");
1588
1589 Dl_info dlinfo;
1590 struct _address_to_library_name data;
1591
1592 // There is a bug in old glibc dladdr() implementation that it could resolve
1593 // to wrong library name if the .so file has a base address != NULL. Here
1594 // we iterate through the program headers of all loaded libraries to find
1595 // out which library 'addr' really belongs to. This workaround can be
1596 // removed once the minimum requirement for glibc is moved to 2.3.x.
1597 data.addr = addr;
1598 data.fname = buf;
1599 data.buflen = buflen;
1600 data.base = NULL;
1601 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1602
1603 if (rslt) {
1604 // buf already contains library name
1605 if (offset) *offset = addr - data.base;
1606 return true;
1607 }
1608 if (dladdr((void*)addr, &dlinfo) != 0) {
1609 if (dlinfo.dli_fname != NULL) {
1610 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1611 }
1612 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1613 *offset = addr - (address)dlinfo.dli_fbase;
1614 }
1615 return true;
1616 }
1617
1618 buf[0] = '\0';
1619 if (offset) *offset = -1;
1620 return false;
1621 }
1622
1623 // Loads .dll/.so and
1624 // in case of error it checks if .dll/.so was built for the
1625 // same architecture as Hotspot is running on
1626
1627
1628 // Remember the stack's state. The Linux dynamic linker will change
1629 // the stack to 'executable' at most once, so we must safepoint only once.
1630 bool os::Linux::_stack_is_executable = false;
1631
1632 // VM operation that loads a library. This is necessary if stack protection
1633 // of the Java stacks can be lost during loading the library. If we
1634 // do not stop the Java threads, they can stack overflow before the stacks
1635 // are protected again.
1636 class VM_LinuxDllLoad: public VM_Operation {
1637 private:
1638 const char *_filename;
1639 char *_ebuf;
1640 int _ebuflen;
1641 void *_lib;
1642 public:
1643 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1644 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1645 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1646 void doit() {
1647 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1648 os::Linux::_stack_is_executable = true;
1649 }
1650 void* loaded_library() { return _lib; }
1651 };
1652
1653 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1654 void * result = NULL;
1655 bool load_attempted = false;
1656
1657 // Check whether the library to load might change execution rights
1658 // of the stack. If they are changed, the protection of the stack
1659 // guard pages will be lost. We need a safepoint to fix this.
1660 //
1661 // See Linux man page execstack(8) for more info.
1662 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1663 if (!ElfFile::specifies_noexecstack(filename)) {
1664 if (!is_init_completed()) {
1665 os::Linux::_stack_is_executable = true;
1666 // This is OK - No Java threads have been created yet, and hence no
1667 // stack guard pages to fix.
1668 //
1669 // Dynamic loader will make all stacks executable after
1670 // this function returns, and will not do that again.
1671 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1672 } else {
1673 warning("You have loaded library %s which might have disabled stack guard. "
1674 "The VM will try to fix the stack guard now.\n"
1675 "It's highly recommended that you fix the library with "
1676 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1677 filename);
1678
1679 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1680 JavaThread *jt = JavaThread::current();
1681 if (jt->thread_state() != _thread_in_native) {
1682 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1683 // that requires ExecStack. Cannot enter safe point. Let's give up.
1684 warning("Unable to fix stack guard. Giving up.");
1685 } else {
1686 if (!LoadExecStackDllInVMThread) {
1687 // This is for the case where the DLL has an static
1688 // constructor function that executes JNI code. We cannot
1689 // load such DLLs in the VMThread.
1690 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1691 }
1692
1693 ThreadInVMfromNative tiv(jt);
1694 debug_only(VMNativeEntryWrapper vew;)
1695
1696 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1697 VMThread::execute(&op);
1698 if (LoadExecStackDllInVMThread) {
1699 result = op.loaded_library();
1700 }
1701 load_attempted = true;
1702 }
1703 }
1704 }
1705 }
1706
1707 if (!load_attempted) {
1708 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1709 }
1710
1711 if (result != NULL) {
1712 // Successful loading
1713 return result;
1714 }
1715
1716 Elf32_Ehdr elf_head;
1717 int diag_msg_max_length=ebuflen-strlen(ebuf);
1718 char* diag_msg_buf=ebuf+strlen(ebuf);
1719
1720 if (diag_msg_max_length==0) {
1721 // No more space in ebuf for additional diagnostics message
1722 return NULL;
1723 }
1724
1725
1726 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1727
1728 if (file_descriptor < 0) {
1729 // Can't open library, report dlerror() message
1730 return NULL;
1731 }
1732
1733 bool failed_to_read_elf_head=
1734 (sizeof(elf_head)!=
1735 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1736
1737 ::close(file_descriptor);
1738 if (failed_to_read_elf_head) {
1739 // file i/o error - report dlerror() msg
1740 return NULL;
1741 }
1742
1743 typedef struct {
1744 Elf32_Half code; // Actual value as defined in elf.h
1745 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1746 unsigned char elf_class; // 32 or 64 bit
1747 unsigned char endianess; // MSB or LSB
1748 char* name; // String representation
1749 } arch_t;
1750
1751 #ifndef EM_486
1752 #define EM_486 6 /* Intel 80486 */
1753 #endif
1754 #ifndef EM_AARCH64
1755 #define EM_AARCH64 183 /* ARM AARCH64 */
1756 #endif
1757
1758 static const arch_t arch_array[]={
1759 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1760 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1761 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1762 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1763 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1764 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1765 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1766 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1767 #if defined(VM_LITTLE_ENDIAN)
1768 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1769 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1770 #else
1771 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1772 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1773 #endif
1774 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1775 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1776 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1777 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1778 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1779 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1780 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1781 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1782 };
1783
1784 #if (defined IA32)
1785 static Elf32_Half running_arch_code=EM_386;
1786 #elif (defined AMD64) || (defined X32)
1787 static Elf32_Half running_arch_code=EM_X86_64;
1788 #elif (defined IA64)
1789 static Elf32_Half running_arch_code=EM_IA_64;
1790 #elif (defined __sparc) && (defined _LP64)
1791 static Elf32_Half running_arch_code=EM_SPARCV9;
1792 #elif (defined __sparc) && (!defined _LP64)
1793 static Elf32_Half running_arch_code=EM_SPARC;
1794 #elif (defined __powerpc64__)
1795 static Elf32_Half running_arch_code=EM_PPC64;
1796 #elif (defined __powerpc__)
1797 static Elf32_Half running_arch_code=EM_PPC;
1798 #elif (defined AARCH64)
1799 static Elf32_Half running_arch_code=EM_AARCH64;
1800 #elif (defined ARM)
1801 static Elf32_Half running_arch_code=EM_ARM;
1802 #elif (defined S390)
1803 static Elf32_Half running_arch_code=EM_S390;
1804 #elif (defined ALPHA)
1805 static Elf32_Half running_arch_code=EM_ALPHA;
1806 #elif (defined MIPSEL)
1807 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1808 #elif (defined PARISC)
1809 static Elf32_Half running_arch_code=EM_PARISC;
1810 #elif (defined MIPS)
1811 static Elf32_Half running_arch_code=EM_MIPS;
1812 #elif (defined M68K)
1813 static Elf32_Half running_arch_code=EM_68K;
1814 #elif (defined SH)
1815 static Elf32_Half running_arch_code=EM_SH;
1816 #else
1817 #error Method os::dll_load requires that one of following is defined:\
1818 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc
1819 #endif
1820
1821 // Identify compatability class for VM's architecture and library's architecture
1822 // Obtain string descriptions for architectures
1823
1824 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1825 int running_arch_index=-1;
1826
1827 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1828 if (running_arch_code == arch_array[i].code) {
1829 running_arch_index = i;
1830 }
1831 if (lib_arch.code == arch_array[i].code) {
1832 lib_arch.compat_class = arch_array[i].compat_class;
1833 lib_arch.name = arch_array[i].name;
1834 }
1835 }
1836
1837 assert(running_arch_index != -1,
1838 "Didn't find running architecture code (running_arch_code) in arch_array");
1839 if (running_arch_index == -1) {
1840 // Even though running architecture detection failed
1841 // we may still continue with reporting dlerror() message
1842 return NULL;
1843 }
1844
1845 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1846 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1847 return NULL;
1848 }
1849
1850 #ifndef S390
1851 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1852 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1853 return NULL;
1854 }
1855 #endif // !S390
1856
1857 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1858 if (lib_arch.name!=NULL) {
1859 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1860 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1861 lib_arch.name, arch_array[running_arch_index].name);
1862 } else {
1863 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1864 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1865 lib_arch.code,
1866 arch_array[running_arch_index].name);
1867 }
1868 }
1869
1870 return NULL;
1871 }
1872
1873 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1874 int ebuflen) {
1875 void * result = ::dlopen(filename, RTLD_LAZY);
1876 if (result == NULL) {
1877 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1878 ebuf[ebuflen-1] = '\0';
1879 }
1880 return result;
1881 }
1882
1883 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1884 int ebuflen) {
1885 void * result = NULL;
1886 if (LoadExecStackDllInVMThread) {
1887 result = dlopen_helper(filename, ebuf, ebuflen);
1888 }
1889
1890 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1891 // library that requires an executable stack, or which does not have this
1892 // stack attribute set, dlopen changes the stack attribute to executable. The
1893 // read protection of the guard pages gets lost.
1894 //
1895 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1896 // may have been queued at the same time.
1897
1898 if (!_stack_is_executable) {
1899 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
1900 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1901 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1902 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1903 warning("Attempt to reguard stack yellow zone failed.");
1904 }
1905 }
1906 }
1907 }
1908
1909 return result;
1910 }
1911
1912 void* os::dll_lookup(void* handle, const char* name) {
1913 void* res = dlsym(handle, name);
1914 return res;
1915 }
1916
1917 void* os::get_default_process_handle() {
1918 return (void*)::dlopen(NULL, RTLD_LAZY);
1919 }
1920
1921 static bool _print_ascii_file(const char* filename, outputStream* st, const char* hdr = NULL) {
1922 int fd = ::open(filename, O_RDONLY);
1923 if (fd == -1) {
1924 return false;
1925 }
1926
1927 if (hdr != NULL) {
1928 st->print_cr("%s", hdr);
1929 }
1930
1931 char buf[33];
1932 int bytes;
1933 buf[32] = '\0';
1934 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1935 st->print_raw(buf, bytes);
1936 }
1937
1938 ::close(fd);
1939
1940 return true;
1941 }
1942
1943 void os::print_dll_info(outputStream *st) {
1944 st->print_cr("Dynamic libraries:");
1945
1946 char fname[32];
1947 pid_t pid = os::Linux::gettid();
1948
1949 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1950
1951 if (!_print_ascii_file(fname, st)) {
1952 st->print("Can not get library information for pid = %d\n", pid);
1953 }
1954 }
1955
1956 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1957 FILE *procmapsFile = NULL;
1958
1959 // Open the procfs maps file for the current process
1960 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1961 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1962 char line[PATH_MAX + 100];
1963
1964 // Read line by line from 'file'
1965 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1966 u8 base, top, offset, inode;
1967 char permissions[5];
1968 char device[6];
1969 char name[PATH_MAX + 1];
1970
1971 // Parse fields from line
1972 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s",
1973 &base, &top, permissions, &offset, device, &inode, name);
1974
1975 // Filter by device id '00:00' so that we only get file system mapped files.
1976 if (strcmp(device, "00:00") != 0) {
1977
1978 // Call callback with the fields of interest
1979 if(callback(name, (address)base, (address)top, param)) {
1980 // Oops abort, callback aborted
1981 fclose(procmapsFile);
1982 return 1;
1983 }
1984 }
1985 }
1986 fclose(procmapsFile);
1987 }
1988 return 0;
1989 }
1990
1991 void os::print_os_info_brief(outputStream* st) {
1992 os::Linux::print_distro_info(st);
1993
1994 os::Posix::print_uname_info(st);
1995
1996 os::Linux::print_libversion_info(st);
1997
1998 }
1999
2000 void os::print_os_info(outputStream* st) {
2001 st->print("OS:");
2002
2003 os::Linux::print_distro_info(st);
2004
2005 os::Posix::print_uname_info(st);
2006
2007 // Print warning if unsafe chroot environment detected
2008 if (unsafe_chroot_detected) {
2009 st->print("WARNING!! ");
2010 st->print_cr("%s", unstable_chroot_error);
2011 }
2012
2013 os::Linux::print_libversion_info(st);
2014
2015 os::Posix::print_rlimit_info(st);
2016
2017 os::Posix::print_load_average(st);
2018
2019 os::Linux::print_full_memory_info(st);
2020
2021 os::Linux::print_proc_sys_info(st);
2022
2023 os::Linux::print_ld_preload_file(st);
2024
2025 os::Linux::print_container_info(st);
2026
2027 VM_Version::print_platform_virtualization_info(st);
2028
2029 os::Linux::print_steal_info(st);
2030 }
2031
2032 // Try to identify popular distros.
2033 // Most Linux distributions have a /etc/XXX-release file, which contains
2034 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2035 // file that also contains the OS version string. Some have more than one
2036 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2037 // /etc/redhat-release.), so the order is important.
2038 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2039 // their own specific XXX-release file as well as a redhat-release file.
2040 // Because of this the XXX-release file needs to be searched for before the
2041 // redhat-release file.
2042 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2043 // search for redhat-release / SuSE-release needs to be before lsb-release.
2044 // Since the lsb-release file is the new standard it needs to be searched
2045 // before the older style release files.
2046 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2047 // next to last resort. The os-release file is a new standard that contains
2048 // distribution information and the system-release file seems to be an old
2049 // standard that has been replaced by the lsb-release and os-release files.
2050 // Searching for the debian_version file is the last resort. It contains
2051 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2052 // "Debian " is printed before the contents of the debian_version file.
2053
2054 const char* distro_files[] = {
2055 "/etc/oracle-release",
2056 "/etc/mandriva-release",
2057 "/etc/mandrake-release",
2058 "/etc/sun-release",
2059 "/etc/redhat-release",
2060 "/etc/SuSE-release",
2061 "/etc/lsb-release",
2062 "/etc/turbolinux-release",
2063 "/etc/gentoo-release",
2064 "/etc/ltib-release",
2065 "/etc/angstrom-version",
2066 "/etc/system-release",
2067 "/etc/os-release",
2068 NULL };
2069
2070 void os::Linux::print_distro_info(outputStream* st) {
2071 for (int i = 0;; i++) {
2072 const char* file = distro_files[i];
2073 if (file == NULL) {
2074 break; // done
2075 }
2076 // If file prints, we found it.
2077 if (_print_ascii_file(file, st)) {
2078 return;
2079 }
2080 }
2081
2082 if (file_exists("/etc/debian_version")) {
2083 st->print("Debian ");
2084 _print_ascii_file("/etc/debian_version", st);
2085 } else {
2086 st->print("Linux");
2087 }
2088 st->cr();
2089 }
2090
2091 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2092 char buf[256];
2093 while (fgets(buf, sizeof(buf), fp)) {
2094 // Edit out extra stuff in expected format
2095 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2096 char* ptr = strstr(buf, "\""); // the name is in quotes
2097 if (ptr != NULL) {
2098 ptr++; // go beyond first quote
2099 char* nl = strchr(ptr, '\"');
2100 if (nl != NULL) *nl = '\0';
2101 strncpy(distro, ptr, length);
2102 } else {
2103 ptr = strstr(buf, "=");
2104 ptr++; // go beyond equals then
2105 char* nl = strchr(ptr, '\n');
2106 if (nl != NULL) *nl = '\0';
2107 strncpy(distro, ptr, length);
2108 }
2109 return;
2110 } else if (get_first_line) {
2111 char* nl = strchr(buf, '\n');
2112 if (nl != NULL) *nl = '\0';
2113 strncpy(distro, buf, length);
2114 return;
2115 }
2116 }
2117 // print last line and close
2118 char* nl = strchr(buf, '\n');
2119 if (nl != NULL) *nl = '\0';
2120 strncpy(distro, buf, length);
2121 }
2122
2123 static void parse_os_info(char* distro, size_t length, const char* file) {
2124 FILE* fp = fopen(file, "r");
2125 if (fp != NULL) {
2126 // if suse format, print out first line
2127 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2128 parse_os_info_helper(fp, distro, length, get_first_line);
2129 fclose(fp);
2130 }
2131 }
2132
2133 void os::get_summary_os_info(char* buf, size_t buflen) {
2134 for (int i = 0;; i++) {
2135 const char* file = distro_files[i];
2136 if (file == NULL) {
2137 break; // ran out of distro_files
2138 }
2139 if (file_exists(file)) {
2140 parse_os_info(buf, buflen, file);
2141 return;
2142 }
2143 }
2144 // special case for debian
2145 if (file_exists("/etc/debian_version")) {
2146 strncpy(buf, "Debian ", buflen);
2147 if (buflen > 7) {
2148 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2149 }
2150 } else {
2151 strncpy(buf, "Linux", buflen);
2152 }
2153 }
2154
2155 void os::Linux::print_libversion_info(outputStream* st) {
2156 // libc, pthread
2157 st->print("libc:");
2158 st->print("%s ", os::Linux::glibc_version());
2159 st->print("%s ", os::Linux::libpthread_version());
2160 st->cr();
2161 }
2162
2163 void os::Linux::print_proc_sys_info(outputStream* st) {
2164 st->cr();
2165 st->print_cr("/proc/sys/kernel/threads-max (system-wide limit on the number of threads):");
2166 _print_ascii_file("/proc/sys/kernel/threads-max", st);
2167 st->cr();
2168 st->cr();
2169
2170 st->print_cr("/proc/sys/vm/max_map_count (maximum number of memory map areas a process may have):");
2171 _print_ascii_file("/proc/sys/vm/max_map_count", st);
2172 st->cr();
2173 st->cr();
2174
2175 st->print_cr("/proc/sys/kernel/pid_max (system-wide limit on number of process identifiers):");
2176 _print_ascii_file("/proc/sys/kernel/pid_max", st);
2177 st->cr();
2178 st->cr();
2179 }
2180
2181 void os::Linux::print_full_memory_info(outputStream* st) {
2182 st->print("\n/proc/meminfo:\n");
2183 _print_ascii_file("/proc/meminfo", st);
2184 st->cr();
2185 }
2186
2187 void os::Linux::print_ld_preload_file(outputStream* st) {
2188 _print_ascii_file("/etc/ld.so.preload", st, "\n/etc/ld.so.preload:");
2189 st->cr();
2190 }
2191
2192 void os::Linux::print_container_info(outputStream* st) {
2193 if (!OSContainer::is_containerized()) {
2194 return;
2195 }
2196
2197 st->print("container (cgroup) information:\n");
2198
2199 const char *p_ct = OSContainer::container_type();
2200 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "not supported");
2201
2202 char *p = OSContainer::cpu_cpuset_cpus();
2203 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "not supported");
2204 free(p);
2205
2206 p = OSContainer::cpu_cpuset_memory_nodes();
2207 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "not supported");
2208 free(p);
2209
2210 int i = OSContainer::active_processor_count();
2211 st->print("active_processor_count: ");
2212 if (i > 0) {
2213 st->print("%d\n", i);
2214 } else {
2215 st->print("not supported\n");
2216 }
2217
2218 i = OSContainer::cpu_quota();
2219 st->print("cpu_quota: ");
2220 if (i > 0) {
2221 st->print("%d\n", i);
2222 } else {
2223 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no quota");
2224 }
2225
2226 i = OSContainer::cpu_period();
2227 st->print("cpu_period: ");
2228 if (i > 0) {
2229 st->print("%d\n", i);
2230 } else {
2231 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no period");
2232 }
2233
2234 i = OSContainer::cpu_shares();
2235 st->print("cpu_shares: ");
2236 if (i > 0) {
2237 st->print("%d\n", i);
2238 } else {
2239 st->print("%s\n", i == OSCONTAINER_ERROR ? "not supported" : "no shares");
2240 }
2241
2242 jlong j = OSContainer::memory_limit_in_bytes();
2243 st->print("memory_limit_in_bytes: ");
2244 if (j > 0) {
2245 st->print(JLONG_FORMAT "\n", j);
2246 } else {
2247 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2248 }
2249
2250 j = OSContainer::memory_and_swap_limit_in_bytes();
2251 st->print("memory_and_swap_limit_in_bytes: ");
2252 if (j > 0) {
2253 st->print(JLONG_FORMAT "\n", j);
2254 } else {
2255 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2256 }
2257
2258 j = OSContainer::memory_soft_limit_in_bytes();
2259 st->print("memory_soft_limit_in_bytes: ");
2260 if (j > 0) {
2261 st->print(JLONG_FORMAT "\n", j);
2262 } else {
2263 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2264 }
2265
2266 j = OSContainer::OSContainer::memory_usage_in_bytes();
2267 st->print("memory_usage_in_bytes: ");
2268 if (j > 0) {
2269 st->print(JLONG_FORMAT "\n", j);
2270 } else {
2271 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2272 }
2273
2274 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2275 st->print("memory_max_usage_in_bytes: ");
2276 if (j > 0) {
2277 st->print(JLONG_FORMAT "\n", j);
2278 } else {
2279 st->print("%s\n", j == OSCONTAINER_ERROR ? "not supported" : "unlimited");
2280 }
2281 st->cr();
2282 }
2283
2284 void os::Linux::print_steal_info(outputStream* st) {
2285 if (has_initial_tick_info) {
2286 CPUPerfTicks pticks;
2287 bool res = os::Linux::get_tick_information(&pticks, -1);
2288
2289 if (res && pticks.has_steal_ticks) {
2290 uint64_t steal_ticks_difference = pticks.steal - initial_steal_ticks;
2291 uint64_t total_ticks_difference = pticks.total - initial_total_ticks;
2292 double steal_ticks_perc = 0.0;
2293 if (total_ticks_difference != 0) {
2294 steal_ticks_perc = (double) steal_ticks_difference / total_ticks_difference;
2295 }
2296 st->print_cr("Steal ticks since vm start: " UINT64_FORMAT, steal_ticks_difference);
2297 st->print_cr("Steal ticks percentage since vm start:%7.3f", steal_ticks_perc);
2298 }
2299 }
2300 }
2301
2302 void os::print_memory_info(outputStream* st) {
2303
2304 st->print("Memory:");
2305 st->print(" %dk page", os::vm_page_size()>>10);
2306
2307 // values in struct sysinfo are "unsigned long"
2308 struct sysinfo si;
2309 sysinfo(&si);
2310
2311 st->print(", physical " UINT64_FORMAT "k",
2312 os::physical_memory() >> 10);
2313 st->print("(" UINT64_FORMAT "k free)",
2314 os::available_memory() >> 10);
2315 st->print(", swap " UINT64_FORMAT "k",
2316 ((jlong)si.totalswap * si.mem_unit) >> 10);
2317 st->print("(" UINT64_FORMAT "k free)",
2318 ((jlong)si.freeswap * si.mem_unit) >> 10);
2319 st->cr();
2320 }
2321
2322 // Print the first "model name" line and the first "flags" line
2323 // that we find and nothing more. We assume "model name" comes
2324 // before "flags" so if we find a second "model name", then the
2325 // "flags" field is considered missing.
2326 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2327 #if defined(IA32) || defined(AMD64)
2328 // Other platforms have less repetitive cpuinfo files
2329 FILE *fp = fopen("/proc/cpuinfo", "r");
2330 if (fp) {
2331 while (!feof(fp)) {
2332 if (fgets(buf, buflen, fp)) {
2333 // Assume model name comes before flags
2334 bool model_name_printed = false;
2335 if (strstr(buf, "model name") != NULL) {
2336 if (!model_name_printed) {
2337 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2338 st->print_raw(buf);
2339 model_name_printed = true;
2340 } else {
2341 // model name printed but not flags? Odd, just return
2342 fclose(fp);
2343 return true;
2344 }
2345 }
2346 // print the flags line too
2347 if (strstr(buf, "flags") != NULL) {
2348 st->print_raw(buf);
2349 fclose(fp);
2350 return true;
2351 }
2352 }
2353 }
2354 fclose(fp);
2355 }
2356 #endif // x86 platforms
2357 return false;
2358 }
2359
2360 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2361 // Only print the model name if the platform provides this as a summary
2362 if (!print_model_name_and_flags(st, buf, buflen)) {
2363 st->print("\n/proc/cpuinfo:\n");
2364 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2365 st->print_cr(" <Not Available>");
2366 }
2367 }
2368 }
2369
2370 #if defined(AMD64) || defined(IA32) || defined(X32)
2371 const char* search_string = "model name";
2372 #elif defined(M68K)
2373 const char* search_string = "CPU";
2374 #elif defined(PPC64)
2375 const char* search_string = "cpu";
2376 #elif defined(S390)
2377 const char* search_string = "machine =";
2378 #elif defined(SPARC)
2379 const char* search_string = "cpu";
2380 #else
2381 const char* search_string = "Processor";
2382 #endif
2383
2384 // Parses the cpuinfo file for string representing the model name.
2385 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2386 FILE* fp = fopen("/proc/cpuinfo", "r");
2387 if (fp != NULL) {
2388 while (!feof(fp)) {
2389 char buf[256];
2390 if (fgets(buf, sizeof(buf), fp)) {
2391 char* start = strstr(buf, search_string);
2392 if (start != NULL) {
2393 char *ptr = start + strlen(search_string);
2394 char *end = buf + strlen(buf);
2395 while (ptr != end) {
2396 // skip whitespace and colon for the rest of the name.
2397 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2398 break;
2399 }
2400 ptr++;
2401 }
2402 if (ptr != end) {
2403 // reasonable string, get rid of newline and keep the rest
2404 char* nl = strchr(buf, '\n');
2405 if (nl != NULL) *nl = '\0';
2406 strncpy(cpuinfo, ptr, length);
2407 fclose(fp);
2408 return;
2409 }
2410 }
2411 }
2412 }
2413 fclose(fp);
2414 }
2415 // cpuinfo not found or parsing failed, just print generic string. The entire
2416 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2417 #if defined(AARCH64)
2418 strncpy(cpuinfo, "AArch64", length);
2419 #elif defined(AMD64)
2420 strncpy(cpuinfo, "x86_64", length);
2421 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2422 strncpy(cpuinfo, "ARM", length);
2423 #elif defined(IA32)
2424 strncpy(cpuinfo, "x86_32", length);
2425 #elif defined(IA64)
2426 strncpy(cpuinfo, "IA64", length);
2427 #elif defined(PPC)
2428 strncpy(cpuinfo, "PPC64", length);
2429 #elif defined(S390)
2430 strncpy(cpuinfo, "S390", length);
2431 #elif defined(SPARC)
2432 strncpy(cpuinfo, "sparcv9", length);
2433 #elif defined(ZERO_LIBARCH)
2434 strncpy(cpuinfo, ZERO_LIBARCH, length);
2435 #else
2436 strncpy(cpuinfo, "unknown", length);
2437 #endif
2438 }
2439
2440 static void print_signal_handler(outputStream* st, int sig,
2441 char* buf, size_t buflen);
2442
2443 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2444 st->print_cr("Signal Handlers:");
2445 print_signal_handler(st, SIGSEGV, buf, buflen);
2446 print_signal_handler(st, SIGBUS , buf, buflen);
2447 print_signal_handler(st, SIGFPE , buf, buflen);
2448 print_signal_handler(st, SIGPIPE, buf, buflen);
2449 print_signal_handler(st, SIGXFSZ, buf, buflen);
2450 print_signal_handler(st, SIGILL , buf, buflen);
2451 print_signal_handler(st, SR_signum, buf, buflen);
2452 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2453 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2454 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2455 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2456 #if defined(PPC64)
2457 print_signal_handler(st, SIGTRAP, buf, buflen);
2458 #endif
2459 }
2460
2461 static char saved_jvm_path[MAXPATHLEN] = {0};
2462
2463 // Find the full path to the current module, libjvm.so
2464 void os::jvm_path(char *buf, jint buflen) {
2465 // Error checking.
2466 if (buflen < MAXPATHLEN) {
2467 assert(false, "must use a large-enough buffer");
2468 buf[0] = '\0';
2469 return;
2470 }
2471 // Lazy resolve the path to current module.
2472 if (saved_jvm_path[0] != 0) {
2473 strcpy(buf, saved_jvm_path);
2474 return;
2475 }
2476
2477 char dli_fname[MAXPATHLEN];
2478 bool ret = dll_address_to_library_name(
2479 CAST_FROM_FN_PTR(address, os::jvm_path),
2480 dli_fname, sizeof(dli_fname), NULL);
2481 assert(ret, "cannot locate libjvm");
2482 char *rp = NULL;
2483 if (ret && dli_fname[0] != '\0') {
2484 rp = os::Posix::realpath(dli_fname, buf, buflen);
2485 }
2486 if (rp == NULL) {
2487 return;
2488 }
2489
2490 if (Arguments::sun_java_launcher_is_altjvm()) {
2491 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2492 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2493 // If "/jre/lib/" appears at the right place in the string, then
2494 // assume we are installed in a JDK and we're done. Otherwise, check
2495 // for a JAVA_HOME environment variable and fix up the path so it
2496 // looks like libjvm.so is installed there (append a fake suffix
2497 // hotspot/libjvm.so).
2498 const char *p = buf + strlen(buf) - 1;
2499 for (int count = 0; p > buf && count < 5; ++count) {
2500 for (--p; p > buf && *p != '/'; --p)
2501 /* empty */ ;
2502 }
2503
2504 if (strncmp(p, "/jre/lib/", 9) != 0) {
2505 // Look for JAVA_HOME in the environment.
2506 char* java_home_var = ::getenv("JAVA_HOME");
2507 if (java_home_var != NULL && java_home_var[0] != 0) {
2508 char* jrelib_p;
2509 int len;
2510
2511 // Check the current module name "libjvm.so".
2512 p = strrchr(buf, '/');
2513 if (p == NULL) {
2514 return;
2515 }
2516 assert(strstr(p, "/libjvm") == p, "invalid library name");
2517
2518 rp = os::Posix::realpath(java_home_var, buf, buflen);
2519 if (rp == NULL) {
2520 return;
2521 }
2522
2523 // determine if this is a legacy image or modules image
2524 // modules image doesn't have "jre" subdirectory
2525 len = strlen(buf);
2526 assert(len < buflen, "Ran out of buffer room");
2527 jrelib_p = buf + len;
2528 snprintf(jrelib_p, buflen-len, "/jre/lib");
2529 if (0 != access(buf, F_OK)) {
2530 snprintf(jrelib_p, buflen-len, "/lib");
2531 }
2532
2533 if (0 == access(buf, F_OK)) {
2534 // Use current module name "libjvm.so"
2535 len = strlen(buf);
2536 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2537 } else {
2538 // Go back to path of .so
2539 rp = os::Posix::realpath(dli_fname, buf, buflen);
2540 if (rp == NULL) {
2541 return;
2542 }
2543 }
2544 }
2545 }
2546 }
2547
2548 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2549 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2550 }
2551
2552 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2553 // no prefix required, not even "_"
2554 }
2555
2556 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2557 // no suffix required
2558 }
2559
2560 ////////////////////////////////////////////////////////////////////////////////
2561 // sun.misc.Signal support
2562
2563 static volatile jint sigint_count = 0;
2564
2565 static void UserHandler(int sig, void *siginfo, void *context) {
2566 // 4511530 - sem_post is serialized and handled by the manager thread. When
2567 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2568 // don't want to flood the manager thread with sem_post requests.
2569 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2570 return;
2571 }
2572
2573 // Ctrl-C is pressed during error reporting, likely because the error
2574 // handler fails to abort. Let VM die immediately.
2575 if (sig == SIGINT && VMError::is_error_reported()) {
2576 os::die();
2577 }
2578
2579 os::signal_notify(sig);
2580 }
2581
2582 void* os::user_handler() {
2583 return CAST_FROM_FN_PTR(void*, UserHandler);
2584 }
2585
2586 extern "C" {
2587 typedef void (*sa_handler_t)(int);
2588 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2589 }
2590
2591 void* os::signal(int signal_number, void* handler) {
2592 struct sigaction sigAct, oldSigAct;
2593
2594 sigfillset(&(sigAct.sa_mask));
2595 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2596 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2597
2598 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2599 // -1 means registration failed
2600 return (void *)-1;
2601 }
2602
2603 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2604 }
2605
2606 void os::signal_raise(int signal_number) {
2607 ::raise(signal_number);
2608 }
2609
2610 // The following code is moved from os.cpp for making this
2611 // code platform specific, which it is by its very nature.
2612
2613 // Will be modified when max signal is changed to be dynamic
2614 int os::sigexitnum_pd() {
2615 return NSIG;
2616 }
2617
2618 // a counter for each possible signal value
2619 static volatile jint pending_signals[NSIG+1] = { 0 };
2620
2621 // Linux(POSIX) specific hand shaking semaphore.
2622 static Semaphore* sig_sem = NULL;
2623 static PosixSemaphore sr_semaphore;
2624
2625 static void jdk_misc_signal_init() {
2626 // Initialize signal structures
2627 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2628
2629 // Initialize signal semaphore
2630 sig_sem = new Semaphore();
2631 }
2632
2633 void os::signal_notify(int sig) {
2634 if (sig_sem != NULL) {
2635 Atomic::inc(&pending_signals[sig]);
2636 sig_sem->signal();
2637 } else {
2638 // Signal thread is not created with ReduceSignalUsage and jdk_misc_signal_init
2639 // initialization isn't called.
2640 assert(ReduceSignalUsage, "signal semaphore should be created");
2641 }
2642 }
2643
2644 static int check_pending_signals() {
2645 Atomic::store(0, &sigint_count);
2646 for (;;) {
2647 for (int i = 0; i < NSIG + 1; i++) {
2648 jint n = pending_signals[i];
2649 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2650 return i;
2651 }
2652 }
2653 JavaThread *thread = JavaThread::current();
2654 ThreadBlockInVM tbivm(thread);
2655
2656 bool threadIsSuspended;
2657 do {
2658 thread->set_suspend_equivalent();
2659 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2660 sig_sem->wait();
2661
2662 // were we externally suspended while we were waiting?
2663 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2664 if (threadIsSuspended) {
2665 // The semaphore has been incremented, but while we were waiting
2666 // another thread suspended us. We don't want to continue running
2667 // while suspended because that would surprise the thread that
2668 // suspended us.
2669 sig_sem->signal();
2670
2671 thread->java_suspend_self();
2672 }
2673 } while (threadIsSuspended);
2674 }
2675 }
2676
2677 int os::signal_wait() {
2678 return check_pending_signals();
2679 }
2680
2681 ////////////////////////////////////////////////////////////////////////////////
2682 // Virtual Memory
2683
2684 int os::vm_page_size() {
2685 // Seems redundant as all get out
2686 assert(os::Linux::page_size() != -1, "must call os::init");
2687 return os::Linux::page_size();
2688 }
2689
2690 // Solaris allocates memory by pages.
2691 int os::vm_allocation_granularity() {
2692 assert(os::Linux::page_size() != -1, "must call os::init");
2693 return os::Linux::page_size();
2694 }
2695
2696 // Rationale behind this function:
2697 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2698 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2699 // samples for JITted code. Here we create private executable mapping over the code cache
2700 // and then we can use standard (well, almost, as mapping can change) way to provide
2701 // info for the reporting script by storing timestamp and location of symbol
2702 void linux_wrap_code(char* base, size_t size) {
2703 static volatile jint cnt = 0;
2704
2705 if (!UseOprofile) {
2706 return;
2707 }
2708
2709 char buf[PATH_MAX+1];
2710 int num = Atomic::add(1, &cnt);
2711
2712 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2713 os::get_temp_directory(), os::current_process_id(), num);
2714 unlink(buf);
2715
2716 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2717
2718 if (fd != -1) {
2719 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2720 if (rv != (off_t)-1) {
2721 if (::write(fd, "", 1) == 1) {
2722 mmap(base, size,
2723 PROT_READ|PROT_WRITE|PROT_EXEC,
2724 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2725 }
2726 }
2727 ::close(fd);
2728 unlink(buf);
2729 }
2730 }
2731
2732 static bool recoverable_mmap_error(int err) {
2733 // See if the error is one we can let the caller handle. This
2734 // list of errno values comes from JBS-6843484. I can't find a
2735 // Linux man page that documents this specific set of errno
2736 // values so while this list currently matches Solaris, it may
2737 // change as we gain experience with this failure mode.
2738 switch (err) {
2739 case EBADF:
2740 case EINVAL:
2741 case ENOTSUP:
2742 // let the caller deal with these errors
2743 return true;
2744
2745 default:
2746 // Any remaining errors on this OS can cause our reserved mapping
2747 // to be lost. That can cause confusion where different data
2748 // structures think they have the same memory mapped. The worst
2749 // scenario is if both the VM and a library think they have the
2750 // same memory mapped.
2751 return false;
2752 }
2753 }
2754
2755 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2756 int err) {
2757 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2758 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2759 os::strerror(err), err);
2760 }
2761
2762 static void warn_fail_commit_memory(char* addr, size_t size,
2763 size_t alignment_hint, bool exec,
2764 int err) {
2765 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2766 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2767 alignment_hint, exec, os::strerror(err), err);
2768 }
2769
2770 // NOTE: Linux kernel does not really reserve the pages for us.
2771 // All it does is to check if there are enough free pages
2772 // left at the time of mmap(). This could be a potential
2773 // problem.
2774 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2775 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2776 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2777 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2778 if (res != (uintptr_t) MAP_FAILED) {
2779 if (UseNUMAInterleaving) {
2780 numa_make_global(addr, size);
2781 }
2782 return 0;
2783 }
2784
2785 int err = errno; // save errno from mmap() call above
2786
2787 if (!recoverable_mmap_error(err)) {
2788 warn_fail_commit_memory(addr, size, exec, err);
2789 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2790 }
2791
2792 return err;
2793 }
2794
2795 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2796 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2797 }
2798
2799 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2800 const char* mesg) {
2801 assert(mesg != NULL, "mesg must be specified");
2802 int err = os::Linux::commit_memory_impl(addr, size, exec);
2803 if (err != 0) {
2804 // the caller wants all commit errors to exit with the specified mesg:
2805 warn_fail_commit_memory(addr, size, exec, err);
2806 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2807 }
2808 }
2809
2810 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2811 #ifndef MAP_HUGETLB
2812 #define MAP_HUGETLB 0x40000
2813 #endif
2814
2815 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2816 #ifndef MADV_HUGEPAGE
2817 #define MADV_HUGEPAGE 14
2818 #endif
2819
2820 int os::Linux::commit_memory_impl(char* addr, size_t size,
2821 size_t alignment_hint, bool exec) {
2822 int err = os::Linux::commit_memory_impl(addr, size, exec);
2823 if (err == 0) {
2824 realign_memory(addr, size, alignment_hint);
2825 }
2826 return err;
2827 }
2828
2829 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2830 bool exec) {
2831 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2832 }
2833
2834 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2835 size_t alignment_hint, bool exec,
2836 const char* mesg) {
2837 assert(mesg != NULL, "mesg must be specified");
2838 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2839 if (err != 0) {
2840 // the caller wants all commit errors to exit with the specified mesg:
2841 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2842 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2843 }
2844 }
2845
2846 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2847 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2848 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2849 // be supported or the memory may already be backed by huge pages.
2850 ::madvise(addr, bytes, MADV_HUGEPAGE);
2851 }
2852 }
2853
2854 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2855 // This method works by doing an mmap over an existing mmaping and effectively discarding
2856 // the existing pages. However it won't work for SHM-based large pages that cannot be
2857 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2858 // small pages on top of the SHM segment. This method always works for small pages, so we
2859 // allow that in any case.
2860 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2861 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2862 }
2863 }
2864
2865 void os::numa_make_global(char *addr, size_t bytes) {
2866 Linux::numa_interleave_memory(addr, bytes);
2867 }
2868
2869 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2870 // bind policy to MPOL_PREFERRED for the current thread.
2871 #define USE_MPOL_PREFERRED 0
2872
2873 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2874 // To make NUMA and large pages more robust when both enabled, we need to ease
2875 // the requirements on where the memory should be allocated. MPOL_BIND is the
2876 // default policy and it will force memory to be allocated on the specified
2877 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2878 // the specified node, but will not force it. Using this policy will prevent
2879 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2880 // free large pages.
2881 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2882 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2883 }
2884
2885 bool os::numa_topology_changed() { return false; }
2886
2887 size_t os::numa_get_groups_num() {
2888 // Return just the number of nodes in which it's possible to allocate memory
2889 // (in numa terminology, configured nodes).
2890 return Linux::numa_num_configured_nodes();
2891 }
2892
2893 int os::numa_get_group_id() {
2894 int cpu_id = Linux::sched_getcpu();
2895 if (cpu_id != -1) {
2896 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2897 if (lgrp_id != -1) {
2898 return lgrp_id;
2899 }
2900 }
2901 return 0;
2902 }
2903
2904 int os::Linux::get_existing_num_nodes() {
2905 int node;
2906 int highest_node_number = Linux::numa_max_node();
2907 int num_nodes = 0;
2908
2909 // Get the total number of nodes in the system including nodes without memory.
2910 for (node = 0; node <= highest_node_number; node++) {
2911 if (is_node_in_existing_nodes(node)) {
2912 num_nodes++;
2913 }
2914 }
2915 return num_nodes;
2916 }
2917
2918 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2919 int highest_node_number = Linux::numa_max_node();
2920 size_t i = 0;
2921
2922 // Map all node ids in which it is possible to allocate memory. Also nodes are
2923 // not always consecutively available, i.e. available from 0 to the highest
2924 // node number. If the nodes have been bound explicitly using numactl membind,
2925 // then allocate memory from those nodes only.
2926 for (int node = 0; node <= highest_node_number; node++) {
2927 if (Linux::is_node_in_bound_nodes((unsigned int)node)) {
2928 ids[i++] = node;
2929 }
2930 }
2931 return i;
2932 }
2933
2934 bool os::get_page_info(char *start, page_info* info) {
2935 return false;
2936 }
2937
2938 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2939 page_info* page_found) {
2940 return end;
2941 }
2942
2943
2944 int os::Linux::sched_getcpu_syscall(void) {
2945 unsigned int cpu = 0;
2946 int retval = -1;
2947
2948 #if defined(IA32)
2949 #ifndef SYS_getcpu
2950 #define SYS_getcpu 318
2951 #endif
2952 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2953 #elif defined(AMD64)
2954 // Unfortunately we have to bring all these macros here from vsyscall.h
2955 // to be able to compile on old linuxes.
2956 #define __NR_vgetcpu 2
2957 #define VSYSCALL_START (-10UL << 20)
2958 #define VSYSCALL_SIZE 1024
2959 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2960 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2961 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2962 retval = vgetcpu(&cpu, NULL, NULL);
2963 #endif
2964
2965 return (retval == -1) ? retval : cpu;
2966 }
2967
2968 void os::Linux::sched_getcpu_init() {
2969 // sched_getcpu() should be in libc.
2970 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2971 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2972
2973 // If it's not, try a direct syscall.
2974 if (sched_getcpu() == -1) {
2975 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2976 (void*)&sched_getcpu_syscall));
2977 }
2978
2979 if (sched_getcpu() == -1) {
2980 vm_exit_during_initialization("getcpu(2) system call not supported by kernel");
2981 }
2982 }
2983
2984 // Something to do with the numa-aware allocator needs these symbols
2985 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2986 extern "C" JNIEXPORT void numa_error(char *where) { }
2987
2988 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
2989 // load symbol from base version instead.
2990 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2991 void *f = dlvsym(handle, name, "libnuma_1.1");
2992 if (f == NULL) {
2993 f = dlsym(handle, name);
2994 }
2995 return f;
2996 }
2997
2998 // Handle request to load libnuma symbol version 1.2 (API v2) only.
2999 // Return NULL if the symbol is not defined in this particular version.
3000 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
3001 return dlvsym(handle, name, "libnuma_1.2");
3002 }
3003
3004 bool os::Linux::libnuma_init() {
3005 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
3006 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
3007 if (handle != NULL) {
3008 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3009 libnuma_dlsym(handle, "numa_node_to_cpus")));
3010 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3011 libnuma_dlsym(handle, "numa_max_node")));
3012 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3013 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3014 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3015 libnuma_dlsym(handle, "numa_available")));
3016 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3017 libnuma_dlsym(handle, "numa_tonode_memory")));
3018 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3019 libnuma_dlsym(handle, "numa_interleave_memory")));
3020 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3021 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3022 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3023 libnuma_dlsym(handle, "numa_set_bind_policy")));
3024 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3025 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3026 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3027 libnuma_dlsym(handle, "numa_distance")));
3028 set_numa_get_membind(CAST_TO_FN_PTR(numa_get_membind_func_t,
3029 libnuma_v2_dlsym(handle, "numa_get_membind")));
3030 set_numa_get_interleave_mask(CAST_TO_FN_PTR(numa_get_interleave_mask_func_t,
3031 libnuma_v2_dlsym(handle, "numa_get_interleave_mask")));
3032
3033 if (numa_available() != -1) {
3034 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3035 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3036 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3037 set_numa_interleave_bitmask(_numa_get_interleave_mask());
3038 set_numa_membind_bitmask(_numa_get_membind());
3039 // Create an index -> node mapping, since nodes are not always consecutive
3040 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3041 rebuild_nindex_to_node_map();
3042 // Create a cpu -> node mapping
3043 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3044 rebuild_cpu_to_node_map();
3045 return true;
3046 }
3047 }
3048 }
3049 return false;
3050 }
3051
3052 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
3053 // Creating guard page is very expensive. Java thread has HotSpot
3054 // guard pages, only enable glibc guard page for non-Java threads.
3055 // (Remember: compiler thread is a Java thread, too!)
3056 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
3057 }
3058
3059 void os::Linux::rebuild_nindex_to_node_map() {
3060 int highest_node_number = Linux::numa_max_node();
3061
3062 nindex_to_node()->clear();
3063 for (int node = 0; node <= highest_node_number; node++) {
3064 if (Linux::is_node_in_existing_nodes(node)) {
3065 nindex_to_node()->append(node);
3066 }
3067 }
3068 }
3069
3070 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3071 // The table is later used in get_node_by_cpu().
3072 void os::Linux::rebuild_cpu_to_node_map() {
3073 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3074 // in libnuma (possible values are starting from 16,
3075 // and continuing up with every other power of 2, but less
3076 // than the maximum number of CPUs supported by kernel), and
3077 // is a subject to change (in libnuma version 2 the requirements
3078 // are more reasonable) we'll just hardcode the number they use
3079 // in the library.
3080 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3081
3082 size_t cpu_num = processor_count();
3083 size_t cpu_map_size = NCPUS / BitsPerCLong;
3084 size_t cpu_map_valid_size =
3085 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3086
3087 cpu_to_node()->clear();
3088 cpu_to_node()->at_grow(cpu_num - 1);
3089
3090 size_t node_num = get_existing_num_nodes();
3091
3092 int distance = 0;
3093 int closest_distance = INT_MAX;
3094 int closest_node = 0;
3095 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3096 for (size_t i = 0; i < node_num; i++) {
3097 // Check if node is configured (not a memory-less node). If it is not, find
3098 // the closest configured node. Check also if node is bound, i.e. it's allowed
3099 // to allocate memory from the node. If it's not allowed, map cpus in that node
3100 // to the closest node from which memory allocation is allowed.
3101 if (!is_node_in_configured_nodes(nindex_to_node()->at(i)) ||
3102 !is_node_in_bound_nodes(nindex_to_node()->at(i))) {
3103 closest_distance = INT_MAX;
3104 // Check distance from all remaining nodes in the system. Ignore distance
3105 // from itself, from another non-configured node, and from another non-bound
3106 // node.
3107 for (size_t m = 0; m < node_num; m++) {
3108 if (m != i &&
3109 is_node_in_configured_nodes(nindex_to_node()->at(m)) &&
3110 is_node_in_bound_nodes(nindex_to_node()->at(m))) {
3111 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3112 // If a closest node is found, update. There is always at least one
3113 // configured and bound node in the system so there is always at least
3114 // one node close.
3115 if (distance != 0 && distance < closest_distance) {
3116 closest_distance = distance;
3117 closest_node = nindex_to_node()->at(m);
3118 }
3119 }
3120 }
3121 } else {
3122 // Current node is already a configured node.
3123 closest_node = nindex_to_node()->at(i);
3124 }
3125
3126 // Get cpus from the original node and map them to the closest node. If node
3127 // is a configured node (not a memory-less node), then original node and
3128 // closest node are the same.
3129 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3130 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3131 if (cpu_map[j] != 0) {
3132 for (size_t k = 0; k < BitsPerCLong; k++) {
3133 if (cpu_map[j] & (1UL << k)) {
3134 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3135 }
3136 }
3137 }
3138 }
3139 }
3140 }
3141 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3142 }
3143
3144 int os::Linux::get_node_by_cpu(int cpu_id) {
3145 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3146 return cpu_to_node()->at(cpu_id);
3147 }
3148 return -1;
3149 }
3150
3151 GrowableArray<int>* os::Linux::_cpu_to_node;
3152 GrowableArray<int>* os::Linux::_nindex_to_node;
3153 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3154 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3155 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3156 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3157 os::Linux::numa_available_func_t os::Linux::_numa_available;
3158 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3159 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3160 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3161 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3162 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3163 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3164 os::Linux::numa_get_membind_func_t os::Linux::_numa_get_membind;
3165 os::Linux::numa_get_interleave_mask_func_t os::Linux::_numa_get_interleave_mask;
3166 os::Linux::NumaAllocationPolicy os::Linux::_current_numa_policy;
3167 unsigned long* os::Linux::_numa_all_nodes;
3168 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3169 struct bitmask* os::Linux::_numa_nodes_ptr;
3170 struct bitmask* os::Linux::_numa_interleave_bitmask;
3171 struct bitmask* os::Linux::_numa_membind_bitmask;
3172
3173 bool os::pd_uncommit_memory(char* addr, size_t size) {
3174 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3175 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3176 return res != (uintptr_t) MAP_FAILED;
3177 }
3178
3179 static address get_stack_commited_bottom(address bottom, size_t size) {
3180 address nbot = bottom;
3181 address ntop = bottom + size;
3182
3183 size_t page_sz = os::vm_page_size();
3184 unsigned pages = size / page_sz;
3185
3186 unsigned char vec[1];
3187 unsigned imin = 1, imax = pages + 1, imid;
3188 int mincore_return_value = 0;
3189
3190 assert(imin <= imax, "Unexpected page size");
3191
3192 while (imin < imax) {
3193 imid = (imax + imin) / 2;
3194 nbot = ntop - (imid * page_sz);
3195
3196 // Use a trick with mincore to check whether the page is mapped or not.
3197 // mincore sets vec to 1 if page resides in memory and to 0 if page
3198 // is swapped output but if page we are asking for is unmapped
3199 // it returns -1,ENOMEM
3200 mincore_return_value = mincore(nbot, page_sz, vec);
3201
3202 if (mincore_return_value == -1) {
3203 // Page is not mapped go up
3204 // to find first mapped page
3205 if (errno != EAGAIN) {
3206 assert(errno == ENOMEM, "Unexpected mincore errno");
3207 imax = imid;
3208 }
3209 } else {
3210 // Page is mapped go down
3211 // to find first not mapped page
3212 imin = imid + 1;
3213 }
3214 }
3215
3216 nbot = nbot + page_sz;
3217
3218 // Adjust stack bottom one page up if last checked page is not mapped
3219 if (mincore_return_value == -1) {
3220 nbot = nbot + page_sz;
3221 }
3222
3223 return nbot;
3224 }
3225
3226 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3227 int mincore_return_value;
3228 const size_t stripe = 1024; // query this many pages each time
3229 unsigned char vec[stripe + 1];
3230 // set a guard
3231 vec[stripe] = 'X';
3232
3233 const size_t page_sz = os::vm_page_size();
3234 size_t pages = size / page_sz;
3235
3236 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3237 assert(is_aligned(size, page_sz), "Size must be page aligned");
3238
3239 committed_start = NULL;
3240
3241 int loops = (pages + stripe - 1) / stripe;
3242 int committed_pages = 0;
3243 address loop_base = start;
3244 bool found_range = false;
3245
3246 for (int index = 0; index < loops && !found_range; index ++) {
3247 assert(pages > 0, "Nothing to do");
3248 int pages_to_query = (pages >= stripe) ? stripe : pages;
3249 pages -= pages_to_query;
3250
3251 // Get stable read
3252 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3253
3254 // During shutdown, some memory goes away without properly notifying NMT,
3255 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3256 // Bailout and return as not committed for now.
3257 if (mincore_return_value == -1 && errno == ENOMEM) {
3258 return false;
3259 }
3260
3261 assert(vec[stripe] == 'X', "overflow guard");
3262 assert(mincore_return_value == 0, "Range must be valid");
3263 // Process this stripe
3264 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3265 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3266 // End of current contiguous region
3267 if (committed_start != NULL) {
3268 found_range = true;
3269 break;
3270 }
3271 } else { // committed
3272 // Start of region
3273 if (committed_start == NULL) {
3274 committed_start = loop_base + page_sz * vecIdx;
3275 }
3276 committed_pages ++;
3277 }
3278 }
3279
3280 loop_base += pages_to_query * page_sz;
3281 }
3282
3283 if (committed_start != NULL) {
3284 assert(committed_pages > 0, "Must have committed region");
3285 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3286 assert(committed_start >= start && committed_start < start + size, "Out of range");
3287 committed_size = page_sz * committed_pages;
3288 return true;
3289 } else {
3290 assert(committed_pages == 0, "Should not have committed region");
3291 return false;
3292 }
3293 }
3294
3295
3296 // Linux uses a growable mapping for the stack, and if the mapping for
3297 // the stack guard pages is not removed when we detach a thread the
3298 // stack cannot grow beyond the pages where the stack guard was
3299 // mapped. If at some point later in the process the stack expands to
3300 // that point, the Linux kernel cannot expand the stack any further
3301 // because the guard pages are in the way, and a segfault occurs.
3302 //
3303 // However, it's essential not to split the stack region by unmapping
3304 // a region (leaving a hole) that's already part of the stack mapping,
3305 // so if the stack mapping has already grown beyond the guard pages at
3306 // the time we create them, we have to truncate the stack mapping.
3307 // So, we need to know the extent of the stack mapping when
3308 // create_stack_guard_pages() is called.
3309
3310 // We only need this for stacks that are growable: at the time of
3311 // writing thread stacks don't use growable mappings (i.e. those
3312 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3313 // only applies to the main thread.
3314
3315 // If the (growable) stack mapping already extends beyond the point
3316 // where we're going to put our guard pages, truncate the mapping at
3317 // that point by munmap()ping it. This ensures that when we later
3318 // munmap() the guard pages we don't leave a hole in the stack
3319 // mapping. This only affects the main/primordial thread
3320
3321 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3322 if (os::is_primordial_thread()) {
3323 // As we manually grow stack up to bottom inside create_attached_thread(),
3324 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3325 // we don't need to do anything special.
3326 // Check it first, before calling heavy function.
3327 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3328 unsigned char vec[1];
3329
3330 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3331 // Fallback to slow path on all errors, including EAGAIN
3332 stack_extent = (uintptr_t) get_stack_commited_bottom(
3333 os::Linux::initial_thread_stack_bottom(),
3334 (size_t)addr - stack_extent);
3335 }
3336
3337 if (stack_extent < (uintptr_t)addr) {
3338 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3339 }
3340 }
3341
3342 return os::commit_memory(addr, size, !ExecMem);
3343 }
3344
3345 // If this is a growable mapping, remove the guard pages entirely by
3346 // munmap()ping them. If not, just call uncommit_memory(). This only
3347 // affects the main/primordial thread, but guard against future OS changes.
3348 // It's safe to always unmap guard pages for primordial thread because we
3349 // always place it right after end of the mapped region.
3350
3351 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3352 uintptr_t stack_extent, stack_base;
3353
3354 if (os::is_primordial_thread()) {
3355 return ::munmap(addr, size) == 0;
3356 }
3357
3358 return os::uncommit_memory(addr, size);
3359 }
3360
3361 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3362 // at 'requested_addr'. If there are existing memory mappings at the same
3363 // location, however, they will be overwritten. If 'fixed' is false,
3364 // 'requested_addr' is only treated as a hint, the return value may or
3365 // may not start from the requested address. Unlike Linux mmap(), this
3366 // function returns NULL to indicate failure.
3367 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3368 char * addr;
3369 int flags;
3370
3371 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3372 if (fixed) {
3373 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3374 flags |= MAP_FIXED;
3375 }
3376
3377 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3378 // touch an uncommitted page. Otherwise, the read/write might
3379 // succeed if we have enough swap space to back the physical page.
3380 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3381 flags, -1, 0);
3382
3383 return addr == MAP_FAILED ? NULL : addr;
3384 }
3385
3386 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3387 // (req_addr != NULL) or with a given alignment.
3388 // - bytes shall be a multiple of alignment.
3389 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3390 // - alignment sets the alignment at which memory shall be allocated.
3391 // It must be a multiple of allocation granularity.
3392 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3393 // req_addr or NULL.
3394 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3395
3396 size_t extra_size = bytes;
3397 if (req_addr == NULL && alignment > 0) {
3398 extra_size += alignment;
3399 }
3400
3401 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3402 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3403 -1, 0);
3404 if (start == MAP_FAILED) {
3405 start = NULL;
3406 } else {
3407 if (req_addr != NULL) {
3408 if (start != req_addr) {
3409 ::munmap(start, extra_size);
3410 start = NULL;
3411 }
3412 } else {
3413 char* const start_aligned = align_up(start, alignment);
3414 char* const end_aligned = start_aligned + bytes;
3415 char* const end = start + extra_size;
3416 if (start_aligned > start) {
3417 ::munmap(start, start_aligned - start);
3418 }
3419 if (end_aligned < end) {
3420 ::munmap(end_aligned, end - end_aligned);
3421 }
3422 start = start_aligned;
3423 }
3424 }
3425 return start;
3426 }
3427
3428 static int anon_munmap(char * addr, size_t size) {
3429 return ::munmap(addr, size) == 0;
3430 }
3431
3432 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3433 size_t alignment_hint) {
3434 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3435 }
3436
3437 bool os::pd_release_memory(char* addr, size_t size) {
3438 return anon_munmap(addr, size);
3439 }
3440
3441 static bool linux_mprotect(char* addr, size_t size, int prot) {
3442 // Linux wants the mprotect address argument to be page aligned.
3443 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3444
3445 // According to SUSv3, mprotect() should only be used with mappings
3446 // established by mmap(), and mmap() always maps whole pages. Unaligned
3447 // 'addr' likely indicates problem in the VM (e.g. trying to change
3448 // protection of malloc'ed or statically allocated memory). Check the
3449 // caller if you hit this assert.
3450 assert(addr == bottom, "sanity check");
3451
3452 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3453 return ::mprotect(bottom, size, prot) == 0;
3454 }
3455
3456 // Set protections specified
3457 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3458 bool is_committed) {
3459 unsigned int p = 0;
3460 switch (prot) {
3461 case MEM_PROT_NONE: p = PROT_NONE; break;
3462 case MEM_PROT_READ: p = PROT_READ; break;
3463 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3464 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3465 default:
3466 ShouldNotReachHere();
3467 }
3468 // is_committed is unused.
3469 return linux_mprotect(addr, bytes, p);
3470 }
3471
3472 bool os::guard_memory(char* addr, size_t size) {
3473 return linux_mprotect(addr, size, PROT_NONE);
3474 }
3475
3476 bool os::unguard_memory(char* addr, size_t size) {
3477 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3478 }
3479
3480 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3481 size_t page_size) {
3482 bool result = false;
3483 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3484 MAP_ANONYMOUS|MAP_PRIVATE,
3485 -1, 0);
3486 if (p != MAP_FAILED) {
3487 void *aligned_p = align_up(p, page_size);
3488
3489 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3490
3491 munmap(p, page_size * 2);
3492 }
3493
3494 if (warn && !result) {
3495 warning("TransparentHugePages is not supported by the operating system.");
3496 }
3497
3498 return result;
3499 }
3500
3501 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3502 bool result = false;
3503 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3504 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3505 -1, 0);
3506
3507 if (p != MAP_FAILED) {
3508 // We don't know if this really is a huge page or not.
3509 FILE *fp = fopen("/proc/self/maps", "r");
3510 if (fp) {
3511 while (!feof(fp)) {
3512 char chars[257];
3513 long x = 0;
3514 if (fgets(chars, sizeof(chars), fp)) {
3515 if (sscanf(chars, "%lx-%*x", &x) == 1
3516 && x == (long)p) {
3517 if (strstr (chars, "hugepage")) {
3518 result = true;
3519 break;
3520 }
3521 }
3522 }
3523 }
3524 fclose(fp);
3525 }
3526 munmap(p, page_size);
3527 }
3528
3529 if (warn && !result) {
3530 warning("HugeTLBFS is not supported by the operating system.");
3531 }
3532
3533 return result;
3534 }
3535
3536 // From the coredump_filter documentation:
3537 //
3538 // - (bit 0) anonymous private memory
3539 // - (bit 1) anonymous shared memory
3540 // - (bit 2) file-backed private memory
3541 // - (bit 3) file-backed shared memory
3542 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3543 // effective only if the bit 2 is cleared)
3544 // - (bit 5) hugetlb private memory
3545 // - (bit 6) hugetlb shared memory
3546 // - (bit 7) dax private memory
3547 // - (bit 8) dax shared memory
3548 //
3549 static void set_coredump_filter(CoredumpFilterBit bit) {
3550 FILE *f;
3551 long cdm;
3552
3553 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3554 return;
3555 }
3556
3557 if (fscanf(f, "%lx", &cdm) != 1) {
3558 fclose(f);
3559 return;
3560 }
3561
3562 long saved_cdm = cdm;
3563 rewind(f);
3564 cdm |= bit;
3565
3566 if (cdm != saved_cdm) {
3567 fprintf(f, "%#lx", cdm);
3568 }
3569
3570 fclose(f);
3571 }
3572
3573 // Large page support
3574
3575 static size_t _large_page_size = 0;
3576
3577 size_t os::Linux::find_large_page_size() {
3578 size_t large_page_size = 0;
3579
3580 // large_page_size on Linux is used to round up heap size. x86 uses either
3581 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3582 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3583 // page as large as 256M.
3584 //
3585 // Here we try to figure out page size by parsing /proc/meminfo and looking
3586 // for a line with the following format:
3587 // Hugepagesize: 2048 kB
3588 //
3589 // If we can't determine the value (e.g. /proc is not mounted, or the text
3590 // format has been changed), we'll use the largest page size supported by
3591 // the processor.
3592
3593 #ifndef ZERO
3594 large_page_size =
3595 AARCH64_ONLY(2 * M)
3596 AMD64_ONLY(2 * M)
3597 ARM32_ONLY(2 * M)
3598 IA32_ONLY(4 * M)
3599 IA64_ONLY(256 * M)
3600 PPC_ONLY(4 * M)
3601 S390_ONLY(1 * M)
3602 SPARC_ONLY(4 * M);
3603 #endif // ZERO
3604
3605 FILE *fp = fopen("/proc/meminfo", "r");
3606 if (fp) {
3607 while (!feof(fp)) {
3608 int x = 0;
3609 char buf[16];
3610 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3611 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3612 large_page_size = x * K;
3613 break;
3614 }
3615 } else {
3616 // skip to next line
3617 for (;;) {
3618 int ch = fgetc(fp);
3619 if (ch == EOF || ch == (int)'\n') break;
3620 }
3621 }
3622 }
3623 fclose(fp);
3624 }
3625
3626 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3627 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3628 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3629 proper_unit_for_byte_size(large_page_size));
3630 }
3631
3632 return large_page_size;
3633 }
3634
3635 size_t os::Linux::setup_large_page_size() {
3636 _large_page_size = Linux::find_large_page_size();
3637 const size_t default_page_size = (size_t)Linux::page_size();
3638 if (_large_page_size > default_page_size) {
3639 _page_sizes[0] = _large_page_size;
3640 _page_sizes[1] = default_page_size;
3641 _page_sizes[2] = 0;
3642 }
3643
3644 return _large_page_size;
3645 }
3646
3647 bool os::Linux::setup_large_page_type(size_t page_size) {
3648 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3649 FLAG_IS_DEFAULT(UseSHM) &&
3650 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3651
3652 // The type of large pages has not been specified by the user.
3653
3654 // Try UseHugeTLBFS and then UseSHM.
3655 UseHugeTLBFS = UseSHM = true;
3656
3657 // Don't try UseTransparentHugePages since there are known
3658 // performance issues with it turned on. This might change in the future.
3659 UseTransparentHugePages = false;
3660 }
3661
3662 if (UseTransparentHugePages) {
3663 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3664 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3665 UseHugeTLBFS = false;
3666 UseSHM = false;
3667 return true;
3668 }
3669 UseTransparentHugePages = false;
3670 }
3671
3672 if (UseHugeTLBFS) {
3673 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3674 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3675 UseSHM = false;
3676 return true;
3677 }
3678 UseHugeTLBFS = false;
3679 }
3680
3681 return UseSHM;
3682 }
3683
3684 void os::large_page_init() {
3685 if (!UseLargePages &&
3686 !UseTransparentHugePages &&
3687 !UseHugeTLBFS &&
3688 !UseSHM) {
3689 // Not using large pages.
3690 return;
3691 }
3692
3693 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3694 // The user explicitly turned off large pages.
3695 // Ignore the rest of the large pages flags.
3696 UseTransparentHugePages = false;
3697 UseHugeTLBFS = false;
3698 UseSHM = false;
3699 return;
3700 }
3701
3702 size_t large_page_size = Linux::setup_large_page_size();
3703 UseLargePages = Linux::setup_large_page_type(large_page_size);
3704
3705 set_coredump_filter(LARGEPAGES_BIT);
3706 }
3707
3708 #ifndef SHM_HUGETLB
3709 #define SHM_HUGETLB 04000
3710 #endif
3711
3712 #define shm_warning_format(format, ...) \
3713 do { \
3714 if (UseLargePages && \
3715 (!FLAG_IS_DEFAULT(UseLargePages) || \
3716 !FLAG_IS_DEFAULT(UseSHM) || \
3717 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3718 warning(format, __VA_ARGS__); \
3719 } \
3720 } while (0)
3721
3722 #define shm_warning(str) shm_warning_format("%s", str)
3723
3724 #define shm_warning_with_errno(str) \
3725 do { \
3726 int err = errno; \
3727 shm_warning_format(str " (error = %d)", err); \
3728 } while (0)
3729
3730 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3731 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3732
3733 if (!is_aligned(alignment, SHMLBA)) {
3734 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3735 return NULL;
3736 }
3737
3738 // To ensure that we get 'alignment' aligned memory from shmat,
3739 // we pre-reserve aligned virtual memory and then attach to that.
3740
3741 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3742 if (pre_reserved_addr == NULL) {
3743 // Couldn't pre-reserve aligned memory.
3744 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3745 return NULL;
3746 }
3747
3748 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3749 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3750
3751 if ((intptr_t)addr == -1) {
3752 int err = errno;
3753 shm_warning_with_errno("Failed to attach shared memory.");
3754
3755 assert(err != EACCES, "Unexpected error");
3756 assert(err != EIDRM, "Unexpected error");
3757 assert(err != EINVAL, "Unexpected error");
3758
3759 // Since we don't know if the kernel unmapped the pre-reserved memory area
3760 // we can't unmap it, since that would potentially unmap memory that was
3761 // mapped from other threads.
3762 return NULL;
3763 }
3764
3765 return addr;
3766 }
3767
3768 static char* shmat_at_address(int shmid, char* req_addr) {
3769 if (!is_aligned(req_addr, SHMLBA)) {
3770 assert(false, "Requested address needs to be SHMLBA aligned");
3771 return NULL;
3772 }
3773
3774 char* addr = (char*)shmat(shmid, req_addr, 0);
3775
3776 if ((intptr_t)addr == -1) {
3777 shm_warning_with_errno("Failed to attach shared memory.");
3778 return NULL;
3779 }
3780
3781 return addr;
3782 }
3783
3784 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3785 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3786 if (req_addr != NULL) {
3787 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3788 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3789 return shmat_at_address(shmid, req_addr);
3790 }
3791
3792 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3793 // return large page size aligned memory addresses when req_addr == NULL.
3794 // However, if the alignment is larger than the large page size, we have
3795 // to manually ensure that the memory returned is 'alignment' aligned.
3796 if (alignment > os::large_page_size()) {
3797 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3798 return shmat_with_alignment(shmid, bytes, alignment);
3799 } else {
3800 return shmat_at_address(shmid, NULL);
3801 }
3802 }
3803
3804 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3805 char* req_addr, bool exec) {
3806 // "exec" is passed in but not used. Creating the shared image for
3807 // the code cache doesn't have an SHM_X executable permission to check.
3808 assert(UseLargePages && UseSHM, "only for SHM large pages");
3809 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3810 assert(is_aligned(req_addr, alignment), "Unaligned address");
3811
3812 if (!is_aligned(bytes, os::large_page_size())) {
3813 return NULL; // Fallback to small pages.
3814 }
3815
3816 // Create a large shared memory region to attach to based on size.
3817 // Currently, size is the total size of the heap.
3818 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3819 if (shmid == -1) {
3820 // Possible reasons for shmget failure:
3821 // 1. shmmax is too small for Java heap.
3822 // > check shmmax value: cat /proc/sys/kernel/shmmax
3823 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3824 // 2. not enough large page memory.
3825 // > check available large pages: cat /proc/meminfo
3826 // > increase amount of large pages:
3827 // echo new_value > /proc/sys/vm/nr_hugepages
3828 // Note 1: different Linux may use different name for this property,
3829 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3830 // Note 2: it's possible there's enough physical memory available but
3831 // they are so fragmented after a long run that they can't
3832 // coalesce into large pages. Try to reserve large pages when
3833 // the system is still "fresh".
3834 shm_warning_with_errno("Failed to reserve shared memory.");
3835 return NULL;
3836 }
3837
3838 // Attach to the region.
3839 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3840
3841 // Remove shmid. If shmat() is successful, the actual shared memory segment
3842 // will be deleted when it's detached by shmdt() or when the process
3843 // terminates. If shmat() is not successful this will remove the shared
3844 // segment immediately.
3845 shmctl(shmid, IPC_RMID, NULL);
3846
3847 return addr;
3848 }
3849
3850 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3851 int error) {
3852 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3853
3854 bool warn_on_failure = UseLargePages &&
3855 (!FLAG_IS_DEFAULT(UseLargePages) ||
3856 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3857 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3858
3859 if (warn_on_failure) {
3860 char msg[128];
3861 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3862 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3863 warning("%s", msg);
3864 }
3865 }
3866
3867 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3868 char* req_addr,
3869 bool exec) {
3870 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3871 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
3872 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3873
3874 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3875 char* addr = (char*)::mmap(req_addr, bytes, prot,
3876 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3877 -1, 0);
3878
3879 if (addr == MAP_FAILED) {
3880 warn_on_large_pages_failure(req_addr, bytes, errno);
3881 return NULL;
3882 }
3883
3884 assert(is_aligned(addr, os::large_page_size()), "Must be");
3885
3886 return addr;
3887 }
3888
3889 // Reserve memory using mmap(MAP_HUGETLB).
3890 // - bytes shall be a multiple of alignment.
3891 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3892 // - alignment sets the alignment at which memory shall be allocated.
3893 // It must be a multiple of allocation granularity.
3894 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3895 // req_addr or NULL.
3896 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3897 size_t alignment,
3898 char* req_addr,
3899 bool exec) {
3900 size_t large_page_size = os::large_page_size();
3901 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3902
3903 assert(is_aligned(req_addr, alignment), "Must be");
3904 assert(is_aligned(bytes, alignment), "Must be");
3905
3906 // First reserve - but not commit - the address range in small pages.
3907 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3908
3909 if (start == NULL) {
3910 return NULL;
3911 }
3912
3913 assert(is_aligned(start, alignment), "Must be");
3914
3915 char* end = start + bytes;
3916
3917 // Find the regions of the allocated chunk that can be promoted to large pages.
3918 char* lp_start = align_up(start, large_page_size);
3919 char* lp_end = align_down(end, large_page_size);
3920
3921 size_t lp_bytes = lp_end - lp_start;
3922
3923 assert(is_aligned(lp_bytes, large_page_size), "Must be");
3924
3925 if (lp_bytes == 0) {
3926 // The mapped region doesn't even span the start and the end of a large page.
3927 // Fall back to allocate a non-special area.
3928 ::munmap(start, end - start);
3929 return NULL;
3930 }
3931
3932 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3933
3934 void* result;
3935
3936 // Commit small-paged leading area.
3937 if (start != lp_start) {
3938 result = ::mmap(start, lp_start - start, prot,
3939 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3940 -1, 0);
3941 if (result == MAP_FAILED) {
3942 ::munmap(lp_start, end - lp_start);
3943 return NULL;
3944 }
3945 }
3946
3947 // Commit large-paged area.
3948 result = ::mmap(lp_start, lp_bytes, prot,
3949 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3950 -1, 0);
3951 if (result == MAP_FAILED) {
3952 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3953 // If the mmap above fails, the large pages region will be unmapped and we
3954 // have regions before and after with small pages. Release these regions.
3955 //
3956 // | mapped | unmapped | mapped |
3957 // ^ ^ ^ ^
3958 // start lp_start lp_end end
3959 //
3960 ::munmap(start, lp_start - start);
3961 ::munmap(lp_end, end - lp_end);
3962 return NULL;
3963 }
3964
3965 // Commit small-paged trailing area.
3966 if (lp_end != end) {
3967 result = ::mmap(lp_end, end - lp_end, prot,
3968 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3969 -1, 0);
3970 if (result == MAP_FAILED) {
3971 ::munmap(start, lp_end - start);
3972 return NULL;
3973 }
3974 }
3975
3976 return start;
3977 }
3978
3979 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3980 size_t alignment,
3981 char* req_addr,
3982 bool exec) {
3983 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3984 assert(is_aligned(req_addr, alignment), "Must be");
3985 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3986 assert(is_power_of_2(os::large_page_size()), "Must be");
3987 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3988
3989 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3990 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3991 } else {
3992 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3993 }
3994 }
3995
3996 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3997 char* req_addr, bool exec) {
3998 assert(UseLargePages, "only for large pages");
3999
4000 char* addr;
4001 if (UseSHM) {
4002 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
4003 } else {
4004 assert(UseHugeTLBFS, "must be");
4005 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
4006 }
4007
4008 if (addr != NULL) {
4009 if (UseNUMAInterleaving) {
4010 numa_make_global(addr, bytes);
4011 }
4012
4013 // The memory is committed
4014 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
4015 }
4016
4017 return addr;
4018 }
4019
4020 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
4021 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
4022 return shmdt(base) == 0;
4023 }
4024
4025 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
4026 return pd_release_memory(base, bytes);
4027 }
4028
4029 bool os::release_memory_special(char* base, size_t bytes) {
4030 bool res;
4031 if (MemTracker::tracking_level() > NMT_minimal) {
4032 Tracker tkr(Tracker::release);
4033 res = os::Linux::release_memory_special_impl(base, bytes);
4034 if (res) {
4035 tkr.record((address)base, bytes);
4036 }
4037
4038 } else {
4039 res = os::Linux::release_memory_special_impl(base, bytes);
4040 }
4041 return res;
4042 }
4043
4044 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
4045 assert(UseLargePages, "only for large pages");
4046 bool res;
4047
4048 if (UseSHM) {
4049 res = os::Linux::release_memory_special_shm(base, bytes);
4050 } else {
4051 assert(UseHugeTLBFS, "must be");
4052 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
4053 }
4054 return res;
4055 }
4056
4057 size_t os::large_page_size() {
4058 return _large_page_size;
4059 }
4060
4061 // With SysV SHM the entire memory region must be allocated as shared
4062 // memory.
4063 // HugeTLBFS allows application to commit large page memory on demand.
4064 // However, when committing memory with HugeTLBFS fails, the region
4065 // that was supposed to be committed will lose the old reservation
4066 // and allow other threads to steal that memory region. Because of this
4067 // behavior we can't commit HugeTLBFS memory.
4068 bool os::can_commit_large_page_memory() {
4069 return UseTransparentHugePages;
4070 }
4071
4072 bool os::can_execute_large_page_memory() {
4073 return UseTransparentHugePages || UseHugeTLBFS;
4074 }
4075
4076 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
4077 assert(file_desc >= 0, "file_desc is not valid");
4078 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
4079 if (result != NULL) {
4080 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
4081 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
4082 }
4083 }
4084 return result;
4085 }
4086
4087 // Reserve memory at an arbitrary address, only if that area is
4088 // available (and not reserved for something else).
4089
4090 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
4091 const int max_tries = 10;
4092 char* base[max_tries];
4093 size_t size[max_tries];
4094 const size_t gap = 0x000000;
4095
4096 // Assert only that the size is a multiple of the page size, since
4097 // that's all that mmap requires, and since that's all we really know
4098 // about at this low abstraction level. If we need higher alignment,
4099 // we can either pass an alignment to this method or verify alignment
4100 // in one of the methods further up the call chain. See bug 5044738.
4101 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
4102
4103 // Repeatedly allocate blocks until the block is allocated at the
4104 // right spot.
4105
4106 // Linux mmap allows caller to pass an address as hint; give it a try first,
4107 // if kernel honors the hint then we can return immediately.
4108 char * addr = anon_mmap(requested_addr, bytes, false);
4109 if (addr == requested_addr) {
4110 return requested_addr;
4111 }
4112
4113 if (addr != NULL) {
4114 // mmap() is successful but it fails to reserve at the requested address
4115 anon_munmap(addr, bytes);
4116 }
4117
4118 int i;
4119 for (i = 0; i < max_tries; ++i) {
4120 base[i] = reserve_memory(bytes);
4121
4122 if (base[i] != NULL) {
4123 // Is this the block we wanted?
4124 if (base[i] == requested_addr) {
4125 size[i] = bytes;
4126 break;
4127 }
4128
4129 // Does this overlap the block we wanted? Give back the overlapped
4130 // parts and try again.
4131
4132 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
4133 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
4134 unmap_memory(base[i], top_overlap);
4135 base[i] += top_overlap;
4136 size[i] = bytes - top_overlap;
4137 } else {
4138 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
4139 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
4140 unmap_memory(requested_addr, bottom_overlap);
4141 size[i] = bytes - bottom_overlap;
4142 } else {
4143 size[i] = bytes;
4144 }
4145 }
4146 }
4147 }
4148
4149 // Give back the unused reserved pieces.
4150
4151 for (int j = 0; j < i; ++j) {
4152 if (base[j] != NULL) {
4153 unmap_memory(base[j], size[j]);
4154 }
4155 }
4156
4157 if (i < max_tries) {
4158 return requested_addr;
4159 } else {
4160 return NULL;
4161 }
4162 }
4163
4164 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4165 void os::infinite_sleep() {
4166 while (true) { // sleep forever ...
4167 ::sleep(100); // ... 100 seconds at a time
4168 }
4169 }
4170
4171 // Used to convert frequent JVM_Yield() to nops
4172 bool os::dont_yield() {
4173 return DontYieldALot;
4174 }
4175
4176 // Linux CFS scheduler (since 2.6.23) does not guarantee sched_yield(2) will
4177 // actually give up the CPU. Since skip buddy (v2.6.28):
4178 //
4179 // * Sets the yielding task as skip buddy for current CPU's run queue.
4180 // * Picks next from run queue, if empty, picks a skip buddy (can be the yielding task).
4181 // * Clears skip buddies for this run queue (yielding task no longer a skip buddy).
4182 //
4183 // An alternative is calling os::naked_short_nanosleep with a small number to avoid
4184 // getting re-scheduled immediately.
4185 //
4186 void os::naked_yield() {
4187 sched_yield();
4188 }
4189
4190 ////////////////////////////////////////////////////////////////////////////////
4191 // thread priority support
4192
4193 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4194 // only supports dynamic priority, static priority must be zero. For real-time
4195 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4196 // However, for large multi-threaded applications, SCHED_RR is not only slower
4197 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4198 // of 5 runs - Sep 2005).
4199 //
4200 // The following code actually changes the niceness of kernel-thread/LWP. It
4201 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4202 // not the entire user process, and user level threads are 1:1 mapped to kernel
4203 // threads. It has always been the case, but could change in the future. For
4204 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4205 // It is only used when ThreadPriorityPolicy=1 and may require system level permission
4206 // (e.g., root privilege or CAP_SYS_NICE capability).
4207
4208 int os::java_to_os_priority[CriticalPriority + 1] = {
4209 19, // 0 Entry should never be used
4210
4211 4, // 1 MinPriority
4212 3, // 2
4213 2, // 3
4214
4215 1, // 4
4216 0, // 5 NormPriority
4217 -1, // 6
4218
4219 -2, // 7
4220 -3, // 8
4221 -4, // 9 NearMaxPriority
4222
4223 -5, // 10 MaxPriority
4224
4225 -5 // 11 CriticalPriority
4226 };
4227
4228 static int prio_init() {
4229 if (ThreadPriorityPolicy == 1) {
4230 if (geteuid() != 0) {
4231 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4232 warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
4233 "e.g., being the root user. If the necessary permission is not " \
4234 "possessed, changes to priority will be silently ignored.");
4235 }
4236 }
4237 }
4238 if (UseCriticalJavaThreadPriority) {
4239 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4240 }
4241 return 0;
4242 }
4243
4244 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4245 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4246
4247 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4248 return (ret == 0) ? OS_OK : OS_ERR;
4249 }
4250
4251 OSReturn os::get_native_priority(const Thread* const thread,
4252 int *priority_ptr) {
4253 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4254 *priority_ptr = java_to_os_priority[NormPriority];
4255 return OS_OK;
4256 }
4257
4258 errno = 0;
4259 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4260 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4261 }
4262
4263 ////////////////////////////////////////////////////////////////////////////////
4264 // suspend/resume support
4265
4266 // The low-level signal-based suspend/resume support is a remnant from the
4267 // old VM-suspension that used to be for java-suspension, safepoints etc,
4268 // within hotspot. Currently used by JFR's OSThreadSampler
4269 //
4270 // The remaining code is greatly simplified from the more general suspension
4271 // code that used to be used.
4272 //
4273 // The protocol is quite simple:
4274 // - suspend:
4275 // - sends a signal to the target thread
4276 // - polls the suspend state of the osthread using a yield loop
4277 // - target thread signal handler (SR_handler) sets suspend state
4278 // and blocks in sigsuspend until continued
4279 // - resume:
4280 // - sets target osthread state to continue
4281 // - sends signal to end the sigsuspend loop in the SR_handler
4282 //
4283 // Note that the SR_lock plays no role in this suspend/resume protocol,
4284 // but is checked for NULL in SR_handler as a thread termination indicator.
4285 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4286 //
4287 // Note that resume_clear_context() and suspend_save_context() are needed
4288 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4289 // which in part is used by:
4290 // - Forte Analyzer: AsyncGetCallTrace()
4291 // - StackBanging: get_frame_at_stack_banging_point()
4292
4293 static void resume_clear_context(OSThread *osthread) {
4294 osthread->set_ucontext(NULL);
4295 osthread->set_siginfo(NULL);
4296 }
4297
4298 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4299 ucontext_t* context) {
4300 osthread->set_ucontext(context);
4301 osthread->set_siginfo(siginfo);
4302 }
4303
4304 // Handler function invoked when a thread's execution is suspended or
4305 // resumed. We have to be careful that only async-safe functions are
4306 // called here (Note: most pthread functions are not async safe and
4307 // should be avoided.)
4308 //
4309 // Note: sigwait() is a more natural fit than sigsuspend() from an
4310 // interface point of view, but sigwait() prevents the signal hander
4311 // from being run. libpthread would get very confused by not having
4312 // its signal handlers run and prevents sigwait()'s use with the
4313 // mutex granting granting signal.
4314 //
4315 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4316 //
4317 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4318 // Save and restore errno to avoid confusing native code with EINTR
4319 // after sigsuspend.
4320 int old_errno = errno;
4321
4322 Thread* thread = Thread::current_or_null_safe();
4323 assert(thread != NULL, "Missing current thread in SR_handler");
4324
4325 // On some systems we have seen signal delivery get "stuck" until the signal
4326 // mask is changed as part of thread termination. Check that the current thread
4327 // has not already terminated (via SR_lock()) - else the following assertion
4328 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4329 // destructor has completed.
4330
4331 if (thread->SR_lock() == NULL) {
4332 return;
4333 }
4334
4335 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4336
4337 OSThread* osthread = thread->osthread();
4338
4339 os::SuspendResume::State current = osthread->sr.state();
4340 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4341 suspend_save_context(osthread, siginfo, context);
4342
4343 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4344 os::SuspendResume::State state = osthread->sr.suspended();
4345 if (state == os::SuspendResume::SR_SUSPENDED) {
4346 sigset_t suspend_set; // signals for sigsuspend()
4347 sigemptyset(&suspend_set);
4348 // get current set of blocked signals and unblock resume signal
4349 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4350 sigdelset(&suspend_set, SR_signum);
4351
4352 sr_semaphore.signal();
4353 // wait here until we are resumed
4354 while (1) {
4355 sigsuspend(&suspend_set);
4356
4357 os::SuspendResume::State result = osthread->sr.running();
4358 if (result == os::SuspendResume::SR_RUNNING) {
4359 sr_semaphore.signal();
4360 break;
4361 }
4362 }
4363
4364 } else if (state == os::SuspendResume::SR_RUNNING) {
4365 // request was cancelled, continue
4366 } else {
4367 ShouldNotReachHere();
4368 }
4369
4370 resume_clear_context(osthread);
4371 } else if (current == os::SuspendResume::SR_RUNNING) {
4372 // request was cancelled, continue
4373 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4374 // ignore
4375 } else {
4376 // ignore
4377 }
4378
4379 errno = old_errno;
4380 }
4381
4382 static int SR_initialize() {
4383 struct sigaction act;
4384 char *s;
4385
4386 // Get signal number to use for suspend/resume
4387 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4388 int sig = ::strtol(s, 0, 10);
4389 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4390 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4391 SR_signum = sig;
4392 } else {
4393 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4394 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4395 }
4396 }
4397
4398 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4399 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4400
4401 sigemptyset(&SR_sigset);
4402 sigaddset(&SR_sigset, SR_signum);
4403
4404 // Set up signal handler for suspend/resume
4405 act.sa_flags = SA_RESTART|SA_SIGINFO;
4406 act.sa_handler = (void (*)(int)) SR_handler;
4407
4408 // SR_signum is blocked by default.
4409 // 4528190 - We also need to block pthread restart signal (32 on all
4410 // supported Linux platforms). Note that LinuxThreads need to block
4411 // this signal for all threads to work properly. So we don't have
4412 // to use hard-coded signal number when setting up the mask.
4413 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4414
4415 if (sigaction(SR_signum, &act, 0) == -1) {
4416 return -1;
4417 }
4418
4419 // Save signal flag
4420 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4421 return 0;
4422 }
4423
4424 static int sr_notify(OSThread* osthread) {
4425 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4426 assert_status(status == 0, status, "pthread_kill");
4427 return status;
4428 }
4429
4430 // "Randomly" selected value for how long we want to spin
4431 // before bailing out on suspending a thread, also how often
4432 // we send a signal to a thread we want to resume
4433 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4434 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4435
4436 // returns true on success and false on error - really an error is fatal
4437 // but this seems the normal response to library errors
4438 static bool do_suspend(OSThread* osthread) {
4439 assert(osthread->sr.is_running(), "thread should be running");
4440 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4441
4442 // mark as suspended and send signal
4443 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4444 // failed to switch, state wasn't running?
4445 ShouldNotReachHere();
4446 return false;
4447 }
4448
4449 if (sr_notify(osthread) != 0) {
4450 ShouldNotReachHere();
4451 }
4452
4453 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4454 while (true) {
4455 if (sr_semaphore.timedwait(2)) {
4456 break;
4457 } else {
4458 // timeout
4459 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4460 if (cancelled == os::SuspendResume::SR_RUNNING) {
4461 return false;
4462 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4463 // make sure that we consume the signal on the semaphore as well
4464 sr_semaphore.wait();
4465 break;
4466 } else {
4467 ShouldNotReachHere();
4468 return false;
4469 }
4470 }
4471 }
4472
4473 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4474 return true;
4475 }
4476
4477 static void do_resume(OSThread* osthread) {
4478 assert(osthread->sr.is_suspended(), "thread should be suspended");
4479 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4480
4481 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4482 // failed to switch to WAKEUP_REQUEST
4483 ShouldNotReachHere();
4484 return;
4485 }
4486
4487 while (true) {
4488 if (sr_notify(osthread) == 0) {
4489 if (sr_semaphore.timedwait(2)) {
4490 if (osthread->sr.is_running()) {
4491 return;
4492 }
4493 }
4494 } else {
4495 ShouldNotReachHere();
4496 }
4497 }
4498
4499 guarantee(osthread->sr.is_running(), "Must be running!");
4500 }
4501
4502 ///////////////////////////////////////////////////////////////////////////////////
4503 // signal handling (except suspend/resume)
4504
4505 // This routine may be used by user applications as a "hook" to catch signals.
4506 // The user-defined signal handler must pass unrecognized signals to this
4507 // routine, and if it returns true (non-zero), then the signal handler must
4508 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4509 // routine will never retun false (zero), but instead will execute a VM panic
4510 // routine kill the process.
4511 //
4512 // If this routine returns false, it is OK to call it again. This allows
4513 // the user-defined signal handler to perform checks either before or after
4514 // the VM performs its own checks. Naturally, the user code would be making
4515 // a serious error if it tried to handle an exception (such as a null check
4516 // or breakpoint) that the VM was generating for its own correct operation.
4517 //
4518 // This routine may recognize any of the following kinds of signals:
4519 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4520 // It should be consulted by handlers for any of those signals.
4521 //
4522 // The caller of this routine must pass in the three arguments supplied
4523 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4524 // field of the structure passed to sigaction(). This routine assumes that
4525 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4526 //
4527 // Note that the VM will print warnings if it detects conflicting signal
4528 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4529 //
4530 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4531 siginfo_t* siginfo,
4532 void* ucontext,
4533 int abort_if_unrecognized);
4534
4535 static void signalHandler(int sig, siginfo_t* info, void* uc) {
4536 assert(info != NULL && uc != NULL, "it must be old kernel");
4537 int orig_errno = errno; // Preserve errno value over signal handler.
4538 JVM_handle_linux_signal(sig, info, uc, true);
4539 errno = orig_errno;
4540 }
4541
4542
4543 // This boolean allows users to forward their own non-matching signals
4544 // to JVM_handle_linux_signal, harmlessly.
4545 bool os::Linux::signal_handlers_are_installed = false;
4546
4547 // For signal-chaining
4548 bool os::Linux::libjsig_is_loaded = false;
4549 typedef struct sigaction *(*get_signal_t)(int);
4550 get_signal_t os::Linux::get_signal_action = NULL;
4551
4552 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4553 struct sigaction *actp = NULL;
4554
4555 if (libjsig_is_loaded) {
4556 // Retrieve the old signal handler from libjsig
4557 actp = (*get_signal_action)(sig);
4558 }
4559 if (actp == NULL) {
4560 // Retrieve the preinstalled signal handler from jvm
4561 actp = os::Posix::get_preinstalled_handler(sig);
4562 }
4563
4564 return actp;
4565 }
4566
4567 static bool call_chained_handler(struct sigaction *actp, int sig,
4568 siginfo_t *siginfo, void *context) {
4569 // Call the old signal handler
4570 if (actp->sa_handler == SIG_DFL) {
4571 // It's more reasonable to let jvm treat it as an unexpected exception
4572 // instead of taking the default action.
4573 return false;
4574 } else if (actp->sa_handler != SIG_IGN) {
4575 if ((actp->sa_flags & SA_NODEFER) == 0) {
4576 // automaticlly block the signal
4577 sigaddset(&(actp->sa_mask), sig);
4578 }
4579
4580 sa_handler_t hand = NULL;
4581 sa_sigaction_t sa = NULL;
4582 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4583 // retrieve the chained handler
4584 if (siginfo_flag_set) {
4585 sa = actp->sa_sigaction;
4586 } else {
4587 hand = actp->sa_handler;
4588 }
4589
4590 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4591 actp->sa_handler = SIG_DFL;
4592 }
4593
4594 // try to honor the signal mask
4595 sigset_t oset;
4596 sigemptyset(&oset);
4597 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4598
4599 // call into the chained handler
4600 if (siginfo_flag_set) {
4601 (*sa)(sig, siginfo, context);
4602 } else {
4603 (*hand)(sig);
4604 }
4605
4606 // restore the signal mask
4607 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4608 }
4609 // Tell jvm's signal handler the signal is taken care of.
4610 return true;
4611 }
4612
4613 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4614 bool chained = false;
4615 // signal-chaining
4616 if (UseSignalChaining) {
4617 struct sigaction *actp = get_chained_signal_action(sig);
4618 if (actp != NULL) {
4619 chained = call_chained_handler(actp, sig, siginfo, context);
4620 }
4621 }
4622 return chained;
4623 }
4624
4625 // for diagnostic
4626 int sigflags[NSIG];
4627
4628 int os::Linux::get_our_sigflags(int sig) {
4629 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4630 return sigflags[sig];
4631 }
4632
4633 void os::Linux::set_our_sigflags(int sig, int flags) {
4634 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4635 if (sig > 0 && sig < NSIG) {
4636 sigflags[sig] = flags;
4637 }
4638 }
4639
4640 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4641 // Check for overwrite.
4642 struct sigaction oldAct;
4643 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4644
4645 void* oldhand = oldAct.sa_sigaction
4646 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4647 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4648 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4649 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4650 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4651 if (AllowUserSignalHandlers || !set_installed) {
4652 // Do not overwrite; user takes responsibility to forward to us.
4653 return;
4654 } else if (UseSignalChaining) {
4655 // save the old handler in jvm
4656 os::Posix::save_preinstalled_handler(sig, oldAct);
4657 // libjsig also interposes the sigaction() call below and saves the
4658 // old sigaction on it own.
4659 } else {
4660 fatal("Encountered unexpected pre-existing sigaction handler "
4661 "%#lx for signal %d.", (long)oldhand, sig);
4662 }
4663 }
4664
4665 struct sigaction sigAct;
4666 sigfillset(&(sigAct.sa_mask));
4667 sigAct.sa_handler = SIG_DFL;
4668 if (!set_installed) {
4669 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4670 } else {
4671 sigAct.sa_sigaction = signalHandler;
4672 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4673 }
4674 // Save flags, which are set by ours
4675 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4676 sigflags[sig] = sigAct.sa_flags;
4677
4678 int ret = sigaction(sig, &sigAct, &oldAct);
4679 assert(ret == 0, "check");
4680
4681 void* oldhand2 = oldAct.sa_sigaction
4682 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4683 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4684 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4685 }
4686
4687 // install signal handlers for signals that HotSpot needs to
4688 // handle in order to support Java-level exception handling.
4689
4690 void os::Linux::install_signal_handlers() {
4691 if (!signal_handlers_are_installed) {
4692 signal_handlers_are_installed = true;
4693
4694 // signal-chaining
4695 typedef void (*signal_setting_t)();
4696 signal_setting_t begin_signal_setting = NULL;
4697 signal_setting_t end_signal_setting = NULL;
4698 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4699 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4700 if (begin_signal_setting != NULL) {
4701 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4702 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4703 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4704 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4705 libjsig_is_loaded = true;
4706 assert(UseSignalChaining, "should enable signal-chaining");
4707 }
4708 if (libjsig_is_loaded) {
4709 // Tell libjsig jvm is setting signal handlers
4710 (*begin_signal_setting)();
4711 }
4712
4713 set_signal_handler(SIGSEGV, true);
4714 set_signal_handler(SIGPIPE, true);
4715 set_signal_handler(SIGBUS, true);
4716 set_signal_handler(SIGILL, true);
4717 set_signal_handler(SIGFPE, true);
4718 #if defined(PPC64)
4719 set_signal_handler(SIGTRAP, true);
4720 #endif
4721 set_signal_handler(SIGXFSZ, true);
4722
4723 if (libjsig_is_loaded) {
4724 // Tell libjsig jvm finishes setting signal handlers
4725 (*end_signal_setting)();
4726 }
4727
4728 // We don't activate signal checker if libjsig is in place, we trust ourselves
4729 // and if UserSignalHandler is installed all bets are off.
4730 // Log that signal checking is off only if -verbose:jni is specified.
4731 if (CheckJNICalls) {
4732 if (libjsig_is_loaded) {
4733 if (PrintJNIResolving) {
4734 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4735 }
4736 check_signals = false;
4737 }
4738 if (AllowUserSignalHandlers) {
4739 if (PrintJNIResolving) {
4740 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4741 }
4742 check_signals = false;
4743 }
4744 }
4745 }
4746 }
4747
4748 // This is the fastest way to get thread cpu time on Linux.
4749 // Returns cpu time (user+sys) for any thread, not only for current.
4750 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4751 // It might work on 2.6.10+ with a special kernel/glibc patch.
4752 // For reference, please, see IEEE Std 1003.1-2004:
4753 // http://www.unix.org/single_unix_specification
4754
4755 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4756 struct timespec tp;
4757 int rc = os::Posix::clock_gettime(clockid, &tp);
4758 assert(rc == 0, "clock_gettime is expected to return 0 code");
4759
4760 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4761 }
4762
4763 void os::Linux::initialize_os_info() {
4764 assert(_os_version == 0, "OS info already initialized");
4765
4766 struct utsname _uname;
4767
4768 uint32_t major;
4769 uint32_t minor;
4770 uint32_t fix;
4771
4772 int rc;
4773
4774 // Kernel version is unknown if
4775 // verification below fails.
4776 _os_version = 0x01000000;
4777
4778 rc = uname(&_uname);
4779 if (rc != -1) {
4780
4781 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4782 if (rc == 3) {
4783
4784 if (major < 256 && minor < 256 && fix < 256) {
4785 // Kernel version format is as expected,
4786 // set it overriding unknown state.
4787 _os_version = (major << 16) |
4788 (minor << 8 ) |
4789 (fix << 0 ) ;
4790 }
4791 }
4792 }
4793 }
4794
4795 uint32_t os::Linux::os_version() {
4796 assert(_os_version != 0, "not initialized");
4797 return _os_version & 0x00FFFFFF;
4798 }
4799
4800 bool os::Linux::os_version_is_known() {
4801 assert(_os_version != 0, "not initialized");
4802 return _os_version & 0x01000000 ? false : true;
4803 }
4804
4805 /////
4806 // glibc on Linux platform uses non-documented flag
4807 // to indicate, that some special sort of signal
4808 // trampoline is used.
4809 // We will never set this flag, and we should
4810 // ignore this flag in our diagnostic
4811 #ifdef SIGNIFICANT_SIGNAL_MASK
4812 #undef SIGNIFICANT_SIGNAL_MASK
4813 #endif
4814 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4815
4816 static const char* get_signal_handler_name(address handler,
4817 char* buf, int buflen) {
4818 int offset = 0;
4819 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4820 if (found) {
4821 // skip directory names
4822 const char *p1, *p2;
4823 p1 = buf;
4824 size_t len = strlen(os::file_separator());
4825 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4826 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4827 } else {
4828 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4829 }
4830 return buf;
4831 }
4832
4833 static void print_signal_handler(outputStream* st, int sig,
4834 char* buf, size_t buflen) {
4835 struct sigaction sa;
4836
4837 sigaction(sig, NULL, &sa);
4838
4839 // See comment for SIGNIFICANT_SIGNAL_MASK define
4840 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4841
4842 st->print("%s: ", os::exception_name(sig, buf, buflen));
4843
4844 address handler = (sa.sa_flags & SA_SIGINFO)
4845 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4846 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4847
4848 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4849 st->print("SIG_DFL");
4850 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4851 st->print("SIG_IGN");
4852 } else {
4853 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4854 }
4855
4856 st->print(", sa_mask[0]=");
4857 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4858
4859 address rh = VMError::get_resetted_sighandler(sig);
4860 // May be, handler was resetted by VMError?
4861 if (rh != NULL) {
4862 handler = rh;
4863 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4864 }
4865
4866 st->print(", sa_flags=");
4867 os::Posix::print_sa_flags(st, sa.sa_flags);
4868
4869 // Check: is it our handler?
4870 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4871 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4872 // It is our signal handler
4873 // check for flags, reset system-used one!
4874 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4875 st->print(
4876 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4877 os::Linux::get_our_sigflags(sig));
4878 }
4879 }
4880 st->cr();
4881 }
4882
4883
4884 #define DO_SIGNAL_CHECK(sig) \
4885 do { \
4886 if (!sigismember(&check_signal_done, sig)) { \
4887 os::Linux::check_signal_handler(sig); \
4888 } \
4889 } while (0)
4890
4891 // This method is a periodic task to check for misbehaving JNI applications
4892 // under CheckJNI, we can add any periodic checks here
4893
4894 void os::run_periodic_checks() {
4895 if (check_signals == false) return;
4896
4897 // SEGV and BUS if overridden could potentially prevent
4898 // generation of hs*.log in the event of a crash, debugging
4899 // such a case can be very challenging, so we absolutely
4900 // check the following for a good measure:
4901 DO_SIGNAL_CHECK(SIGSEGV);
4902 DO_SIGNAL_CHECK(SIGILL);
4903 DO_SIGNAL_CHECK(SIGFPE);
4904 DO_SIGNAL_CHECK(SIGBUS);
4905 DO_SIGNAL_CHECK(SIGPIPE);
4906 DO_SIGNAL_CHECK(SIGXFSZ);
4907 #if defined(PPC64)
4908 DO_SIGNAL_CHECK(SIGTRAP);
4909 #endif
4910
4911 // ReduceSignalUsage allows the user to override these handlers
4912 // see comments at the very top and jvm_md.h
4913 if (!ReduceSignalUsage) {
4914 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4915 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4916 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4917 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4918 }
4919
4920 DO_SIGNAL_CHECK(SR_signum);
4921 }
4922
4923 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4924
4925 static os_sigaction_t os_sigaction = NULL;
4926
4927 void os::Linux::check_signal_handler(int sig) {
4928 char buf[O_BUFLEN];
4929 address jvmHandler = NULL;
4930
4931
4932 struct sigaction act;
4933 if (os_sigaction == NULL) {
4934 // only trust the default sigaction, in case it has been interposed
4935 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4936 if (os_sigaction == NULL) return;
4937 }
4938
4939 os_sigaction(sig, (struct sigaction*)NULL, &act);
4940
4941
4942 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4943
4944 address thisHandler = (act.sa_flags & SA_SIGINFO)
4945 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4946 : CAST_FROM_FN_PTR(address, act.sa_handler);
4947
4948
4949 switch (sig) {
4950 case SIGSEGV:
4951 case SIGBUS:
4952 case SIGFPE:
4953 case SIGPIPE:
4954 case SIGILL:
4955 case SIGXFSZ:
4956 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4957 break;
4958
4959 case SHUTDOWN1_SIGNAL:
4960 case SHUTDOWN2_SIGNAL:
4961 case SHUTDOWN3_SIGNAL:
4962 case BREAK_SIGNAL:
4963 jvmHandler = (address)user_handler();
4964 break;
4965
4966 default:
4967 if (sig == SR_signum) {
4968 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4969 } else {
4970 return;
4971 }
4972 break;
4973 }
4974
4975 if (thisHandler != jvmHandler) {
4976 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4977 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4978 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4979 // No need to check this sig any longer
4980 sigaddset(&check_signal_done, sig);
4981 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4982 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4983 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4984 exception_name(sig, buf, O_BUFLEN));
4985 }
4986 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4987 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4988 tty->print("expected:");
4989 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4990 tty->cr();
4991 tty->print(" found:");
4992 os::Posix::print_sa_flags(tty, act.sa_flags);
4993 tty->cr();
4994 // No need to check this sig any longer
4995 sigaddset(&check_signal_done, sig);
4996 }
4997
4998 // Dump all the signal
4999 if (sigismember(&check_signal_done, sig)) {
5000 print_signal_handlers(tty, buf, O_BUFLEN);
5001 }
5002 }
5003
5004 extern void report_error(char* file_name, int line_no, char* title,
5005 char* format, ...);
5006
5007 // this is called _before_ most of the global arguments have been parsed
5008 void os::init(void) {
5009 char dummy; // used to get a guess on initial stack address
5010
5011 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5012
5013 init_random(1234567);
5014
5015 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5016 if (Linux::page_size() == -1) {
5017 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
5018 os::strerror(errno));
5019 }
5020 init_page_sizes((size_t) Linux::page_size());
5021
5022 Linux::initialize_system_info();
5023
5024 Linux::initialize_os_info();
5025
5026 os::Linux::CPUPerfTicks pticks;
5027 bool res = os::Linux::get_tick_information(&pticks, -1);
5028
5029 if (res && pticks.has_steal_ticks) {
5030 has_initial_tick_info = true;
5031 initial_total_ticks = pticks.total;
5032 initial_steal_ticks = pticks.steal;
5033 }
5034
5035 // _main_thread points to the thread that created/loaded the JVM.
5036 Linux::_main_thread = pthread_self();
5037
5038 // retrieve entry point for pthread_setname_np
5039 Linux::_pthread_setname_np =
5040 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5041
5042 os::Posix::init();
5043
5044 initial_time_count = javaTimeNanos();
5045
5046 // Always warn if no monotonic clock available
5047 if (!os::Posix::supports_monotonic_clock()) {
5048 warning("No monotonic clock was available - timed services may " \
5049 "be adversely affected if the time-of-day clock changes");
5050 }
5051 }
5052
5053 // To install functions for atexit system call
5054 extern "C" {
5055 static void perfMemory_exit_helper() {
5056 perfMemory_exit();
5057 }
5058 }
5059
5060 void os::pd_init_container_support() {
5061 OSContainer::init();
5062 }
5063
5064 void os::Linux::numa_init() {
5065
5066 // Java can be invoked as
5067 // 1. Without numactl and heap will be allocated/configured on all nodes as
5068 // per the system policy.
5069 // 2. With numactl --interleave:
5070 // Use numa_get_interleave_mask(v2) API to get nodes bitmask. The same
5071 // API for membind case bitmask is reset.
5072 // Interleave is only hint and Kernel can fallback to other nodes if
5073 // no memory is available on the target nodes.
5074 // 3. With numactl --membind:
5075 // Use numa_get_membind(v2) API to get nodes bitmask. The same API for
5076 // interleave case returns bitmask of all nodes.
5077 // numa_all_nodes_ptr holds bitmask of all nodes.
5078 // numa_get_interleave_mask(v2) and numa_get_membind(v2) APIs returns correct
5079 // bitmask when externally configured to run on all or fewer nodes.
5080
5081 if (!Linux::libnuma_init()) {
5082 UseNUMA = false;
5083 } else {
5084 if ((Linux::numa_max_node() < 1) || Linux::is_bound_to_single_node()) {
5085 // If there's only one node (they start from 0) or if the process
5086 // is bound explicitly to a single node using membind, disable NUMA.
5087 UseNUMA = false;
5088 } else {
5089
5090 LogTarget(Info,os) log;
5091 LogStream ls(log);
5092
5093 Linux::set_configured_numa_policy(Linux::identify_numa_policy());
5094
5095 struct bitmask* bmp = Linux::_numa_membind_bitmask;
5096 const char* numa_mode = "membind";
5097
5098 if (Linux::is_running_in_interleave_mode()) {
5099 bmp = Linux::_numa_interleave_bitmask;
5100 numa_mode = "interleave";
5101 }
5102
5103 ls.print("UseNUMA is enabled and invoked in '%s' mode."
5104 " Heap will be configured using NUMA memory nodes:", numa_mode);
5105
5106 for (int node = 0; node <= Linux::numa_max_node(); node++) {
5107 if (Linux::_numa_bitmask_isbitset(bmp, node)) {
5108 ls.print(" %d", node);
5109 }
5110 }
5111 }
5112 }
5113
5114 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5115 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5116 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5117 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5118 // and disable adaptive resizing.
5119 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5120 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5121 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5122 UseAdaptiveSizePolicy = false;
5123 UseAdaptiveNUMAChunkSizing = false;
5124 }
5125 }
5126
5127 if (!UseNUMA && ForceNUMA) {
5128 UseNUMA = true;
5129 }
5130 }
5131
5132 // this is called _after_ the global arguments have been parsed
5133 jint os::init_2(void) {
5134
5135 // This could be set after os::Posix::init() but all platforms
5136 // have to set it the same so we have to mirror Solaris.
5137 DEBUG_ONLY(os::set_mutex_init_done();)
5138
5139 os::Posix::init_2();
5140
5141 Linux::fast_thread_clock_init();
5142
5143 // initialize suspend/resume support - must do this before signal_sets_init()
5144 if (SR_initialize() != 0) {
5145 perror("SR_initialize failed");
5146 return JNI_ERR;
5147 }
5148
5149 Linux::signal_sets_init();
5150 Linux::install_signal_handlers();
5151 // Initialize data for jdk.internal.misc.Signal
5152 if (!ReduceSignalUsage) {
5153 jdk_misc_signal_init();
5154 }
5155
5156 // Check and sets minimum stack sizes against command line options
5157 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5158 return JNI_ERR;
5159 }
5160
5161 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5162 if (!suppress_primordial_thread_resolution) {
5163 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5164 }
5165
5166 #if defined(IA32)
5167 workaround_expand_exec_shield_cs_limit();
5168 #endif
5169
5170 Linux::libpthread_init();
5171 Linux::sched_getcpu_init();
5172 log_info(os)("HotSpot is running with %s, %s",
5173 Linux::glibc_version(), Linux::libpthread_version());
5174
5175 if (UseNUMA) {
5176 Linux::numa_init();
5177 }
5178
5179 if (MaxFDLimit) {
5180 // set the number of file descriptors to max. print out error
5181 // if getrlimit/setrlimit fails but continue regardless.
5182 struct rlimit nbr_files;
5183 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5184 if (status != 0) {
5185 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5186 } else {
5187 nbr_files.rlim_cur = nbr_files.rlim_max;
5188 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5189 if (status != 0) {
5190 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5191 }
5192 }
5193 }
5194
5195 // Initialize lock used to serialize thread creation (see os::create_thread)
5196 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
5197
5198 // at-exit methods are called in the reverse order of their registration.
5199 // atexit functions are called on return from main or as a result of a
5200 // call to exit(3C). There can be only 32 of these functions registered
5201 // and atexit() does not set errno.
5202
5203 if (PerfAllowAtExitRegistration) {
5204 // only register atexit functions if PerfAllowAtExitRegistration is set.
5205 // atexit functions can be delayed until process exit time, which
5206 // can be problematic for embedded VM situations. Embedded VMs should
5207 // call DestroyJavaVM() to assure that VM resources are released.
5208
5209 // note: perfMemory_exit_helper atexit function may be removed in
5210 // the future if the appropriate cleanup code can be added to the
5211 // VM_Exit VMOperation's doit method.
5212 if (atexit(perfMemory_exit_helper) != 0) {
5213 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5214 }
5215 }
5216
5217 // initialize thread priority policy
5218 prio_init();
5219
5220 if (!FLAG_IS_DEFAULT(AllocateHeapAt) || !FLAG_IS_DEFAULT(AllocateOldGenAt)) {
5221 set_coredump_filter(DAX_SHARED_BIT);
5222 }
5223
5224 if (DumpPrivateMappingsInCore) {
5225 set_coredump_filter(FILE_BACKED_PVT_BIT);
5226 }
5227
5228 if (DumpSharedMappingsInCore) {
5229 set_coredump_filter(FILE_BACKED_SHARED_BIT);
5230 }
5231
5232 return JNI_OK;
5233 }
5234
5235 // Mark the polling page as unreadable
5236 void os::make_polling_page_unreadable(void) {
5237 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
5238 fatal("Could not disable polling page");
5239 }
5240 }
5241
5242 // Mark the polling page as readable
5243 void os::make_polling_page_readable(void) {
5244 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5245 fatal("Could not enable polling page");
5246 }
5247 }
5248
5249 // older glibc versions don't have this macro (which expands to
5250 // an optimized bit-counting function) so we have to roll our own
5251 #ifndef CPU_COUNT
5252
5253 static int _cpu_count(const cpu_set_t* cpus) {
5254 int count = 0;
5255 // only look up to the number of configured processors
5256 for (int i = 0; i < os::processor_count(); i++) {
5257 if (CPU_ISSET(i, cpus)) {
5258 count++;
5259 }
5260 }
5261 return count;
5262 }
5263
5264 #define CPU_COUNT(cpus) _cpu_count(cpus)
5265
5266 #endif // CPU_COUNT
5267
5268 // Get the current number of available processors for this process.
5269 // This value can change at any time during a process's lifetime.
5270 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5271 // If it appears there may be more than 1024 processors then we do a
5272 // dynamic check - see 6515172 for details.
5273 // If anything goes wrong we fallback to returning the number of online
5274 // processors - which can be greater than the number available to the process.
5275 int os::Linux::active_processor_count() {
5276 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5277 cpu_set_t* cpus_p = &cpus;
5278 int cpus_size = sizeof(cpu_set_t);
5279
5280 int configured_cpus = os::processor_count(); // upper bound on available cpus
5281 int cpu_count = 0;
5282
5283 // old build platforms may not support dynamic cpu sets
5284 #ifdef CPU_ALLOC
5285
5286 // To enable easy testing of the dynamic path on different platforms we
5287 // introduce a diagnostic flag: UseCpuAllocPath
5288 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5289 // kernel may use a mask bigger than cpu_set_t
5290 log_trace(os)("active_processor_count: using dynamic path %s"
5291 "- configured processors: %d",
5292 UseCpuAllocPath ? "(forced) " : "",
5293 configured_cpus);
5294 cpus_p = CPU_ALLOC(configured_cpus);
5295 if (cpus_p != NULL) {
5296 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5297 // zero it just to be safe
5298 CPU_ZERO_S(cpus_size, cpus_p);
5299 }
5300 else {
5301 // failed to allocate so fallback to online cpus
5302 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5303 log_trace(os)("active_processor_count: "
5304 "CPU_ALLOC failed (%s) - using "
5305 "online processor count: %d",
5306 os::strerror(errno), online_cpus);
5307 return online_cpus;
5308 }
5309 }
5310 else {
5311 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5312 configured_cpus);
5313 }
5314 #else // CPU_ALLOC
5315 // these stubs won't be executed
5316 #define CPU_COUNT_S(size, cpus) -1
5317 #define CPU_FREE(cpus)
5318
5319 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5320 configured_cpus);
5321 #endif // CPU_ALLOC
5322
5323 // pid 0 means the current thread - which we have to assume represents the process
5324 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5325 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5326 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5327 }
5328 else {
5329 cpu_count = CPU_COUNT(cpus_p);
5330 }
5331 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5332 }
5333 else {
5334 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5335 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5336 "which may exceed available processors", os::strerror(errno), cpu_count);
5337 }
5338
5339 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5340 CPU_FREE(cpus_p);
5341 }
5342
5343 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5344 return cpu_count;
5345 }
5346
5347 // Determine the active processor count from one of
5348 // three different sources:
5349 //
5350 // 1. User option -XX:ActiveProcessorCount
5351 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5352 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5353 //
5354 // Option 1, if specified, will always override.
5355 // If the cgroup subsystem is active and configured, we
5356 // will return the min of the cgroup and option 2 results.
5357 // This is required since tools, such as numactl, that
5358 // alter cpu affinity do not update cgroup subsystem
5359 // cpuset configuration files.
5360 int os::active_processor_count() {
5361 // User has overridden the number of active processors
5362 if (ActiveProcessorCount > 0) {
5363 log_trace(os)("active_processor_count: "
5364 "active processor count set by user : %d",
5365 ActiveProcessorCount);
5366 return ActiveProcessorCount;
5367 }
5368
5369 int active_cpus;
5370 if (OSContainer::is_containerized()) {
5371 active_cpus = OSContainer::active_processor_count();
5372 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5373 active_cpus);
5374 } else {
5375 active_cpus = os::Linux::active_processor_count();
5376 }
5377
5378 return active_cpus;
5379 }
5380
5381 uint os::processor_id() {
5382 const int id = Linux::sched_getcpu();
5383 assert(id >= 0 && id < _processor_count, "Invalid processor id");
5384 return (uint)id;
5385 }
5386
5387 void os::set_native_thread_name(const char *name) {
5388 if (Linux::_pthread_setname_np) {
5389 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5390 snprintf(buf, sizeof(buf), "%s", name);
5391 buf[sizeof(buf) - 1] = '\0';
5392 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5393 // ERANGE should not happen; all other errors should just be ignored.
5394 assert(rc != ERANGE, "pthread_setname_np failed");
5395 }
5396 }
5397
5398 bool os::distribute_processes(uint length, uint* distribution) {
5399 // Not yet implemented.
5400 return false;
5401 }
5402
5403 bool os::bind_to_processor(uint processor_id) {
5404 // Not yet implemented.
5405 return false;
5406 }
5407
5408 ///
5409
5410 void os::SuspendedThreadTask::internal_do_task() {
5411 if (do_suspend(_thread->osthread())) {
5412 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5413 do_task(context);
5414 do_resume(_thread->osthread());
5415 }
5416 }
5417
5418 ////////////////////////////////////////////////////////////////////////////////
5419 // debug support
5420
5421 bool os::find(address addr, outputStream* st) {
5422 Dl_info dlinfo;
5423 memset(&dlinfo, 0, sizeof(dlinfo));
5424 if (dladdr(addr, &dlinfo) != 0) {
5425 st->print(PTR_FORMAT ": ", p2i(addr));
5426 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5427 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5428 p2i(addr) - p2i(dlinfo.dli_saddr));
5429 } else if (dlinfo.dli_fbase != NULL) {
5430 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5431 } else {
5432 st->print("<absolute address>");
5433 }
5434 if (dlinfo.dli_fname != NULL) {
5435 st->print(" in %s", dlinfo.dli_fname);
5436 }
5437 if (dlinfo.dli_fbase != NULL) {
5438 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5439 }
5440 st->cr();
5441
5442 if (Verbose) {
5443 // decode some bytes around the PC
5444 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5445 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5446 address lowest = (address) dlinfo.dli_sname;
5447 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5448 if (begin < lowest) begin = lowest;
5449 Dl_info dlinfo2;
5450 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5451 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5452 end = (address) dlinfo2.dli_saddr;
5453 }
5454 Disassembler::decode(begin, end, st);
5455 }
5456 return true;
5457 }
5458 return false;
5459 }
5460
5461 ////////////////////////////////////////////////////////////////////////////////
5462 // misc
5463
5464 // This does not do anything on Linux. This is basically a hook for being
5465 // able to use structured exception handling (thread-local exception filters)
5466 // on, e.g., Win32.
5467 void
5468 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5469 JavaCallArguments* args, Thread* thread) {
5470 f(value, method, args, thread);
5471 }
5472
5473 void os::print_statistics() {
5474 }
5475
5476 bool os::message_box(const char* title, const char* message) {
5477 int i;
5478 fdStream err(defaultStream::error_fd());
5479 for (i = 0; i < 78; i++) err.print_raw("=");
5480 err.cr();
5481 err.print_raw_cr(title);
5482 for (i = 0; i < 78; i++) err.print_raw("-");
5483 err.cr();
5484 err.print_raw_cr(message);
5485 for (i = 0; i < 78; i++) err.print_raw("=");
5486 err.cr();
5487
5488 char buf[16];
5489 // Prevent process from exiting upon "read error" without consuming all CPU
5490 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5491
5492 return buf[0] == 'y' || buf[0] == 'Y';
5493 }
5494
5495 // Is a (classpath) directory empty?
5496 bool os::dir_is_empty(const char* path) {
5497 DIR *dir = NULL;
5498 struct dirent *ptr;
5499
5500 dir = opendir(path);
5501 if (dir == NULL) return true;
5502
5503 // Scan the directory
5504 bool result = true;
5505 while (result && (ptr = readdir(dir)) != NULL) {
5506 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5507 result = false;
5508 }
5509 }
5510 closedir(dir);
5511 return result;
5512 }
5513
5514 // This code originates from JDK's sysOpen and open64_w
5515 // from src/solaris/hpi/src/system_md.c
5516
5517 int os::open(const char *path, int oflag, int mode) {
5518 if (strlen(path) > MAX_PATH - 1) {
5519 errno = ENAMETOOLONG;
5520 return -1;
5521 }
5522
5523 // All file descriptors that are opened in the Java process and not
5524 // specifically destined for a subprocess should have the close-on-exec
5525 // flag set. If we don't set it, then careless 3rd party native code
5526 // might fork and exec without closing all appropriate file descriptors
5527 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5528 // turn might:
5529 //
5530 // - cause end-of-file to fail to be detected on some file
5531 // descriptors, resulting in mysterious hangs, or
5532 //
5533 // - might cause an fopen in the subprocess to fail on a system
5534 // suffering from bug 1085341.
5535 //
5536 // (Yes, the default setting of the close-on-exec flag is a Unix
5537 // design flaw)
5538 //
5539 // See:
5540 // 1085341: 32-bit stdio routines should support file descriptors >255
5541 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5542 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5543 //
5544 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5545 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5546 // because it saves a system call and removes a small window where the flag
5547 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5548 // and we fall back to using FD_CLOEXEC (see below).
5549 #ifdef O_CLOEXEC
5550 oflag |= O_CLOEXEC;
5551 #endif
5552
5553 int fd = ::open64(path, oflag, mode);
5554 if (fd == -1) return -1;
5555
5556 //If the open succeeded, the file might still be a directory
5557 {
5558 struct stat64 buf64;
5559 int ret = ::fstat64(fd, &buf64);
5560 int st_mode = buf64.st_mode;
5561
5562 if (ret != -1) {
5563 if ((st_mode & S_IFMT) == S_IFDIR) {
5564 errno = EISDIR;
5565 ::close(fd);
5566 return -1;
5567 }
5568 } else {
5569 ::close(fd);
5570 return -1;
5571 }
5572 }
5573
5574 #ifdef FD_CLOEXEC
5575 // Validate that the use of the O_CLOEXEC flag on open above worked.
5576 // With recent kernels, we will perform this check exactly once.
5577 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5578 if (!O_CLOEXEC_is_known_to_work) {
5579 int flags = ::fcntl(fd, F_GETFD);
5580 if (flags != -1) {
5581 if ((flags & FD_CLOEXEC) != 0)
5582 O_CLOEXEC_is_known_to_work = 1;
5583 else
5584 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5585 }
5586 }
5587 #endif
5588
5589 return fd;
5590 }
5591
5592
5593 // create binary file, rewriting existing file if required
5594 int os::create_binary_file(const char* path, bool rewrite_existing) {
5595 int oflags = O_WRONLY | O_CREAT;
5596 if (!rewrite_existing) {
5597 oflags |= O_EXCL;
5598 }
5599 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5600 }
5601
5602 // return current position of file pointer
5603 jlong os::current_file_offset(int fd) {
5604 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5605 }
5606
5607 // move file pointer to the specified offset
5608 jlong os::seek_to_file_offset(int fd, jlong offset) {
5609 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5610 }
5611
5612 // This code originates from JDK's sysAvailable
5613 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5614
5615 int os::available(int fd, jlong *bytes) {
5616 jlong cur, end;
5617 int mode;
5618 struct stat64 buf64;
5619
5620 if (::fstat64(fd, &buf64) >= 0) {
5621 mode = buf64.st_mode;
5622 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5623 int n;
5624 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5625 *bytes = n;
5626 return 1;
5627 }
5628 }
5629 }
5630 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5631 return 0;
5632 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5633 return 0;
5634 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5635 return 0;
5636 }
5637 *bytes = end - cur;
5638 return 1;
5639 }
5640
5641 // Map a block of memory.
5642 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5643 char *addr, size_t bytes, bool read_only,
5644 bool allow_exec) {
5645 int prot;
5646 int flags = MAP_PRIVATE;
5647
5648 if (read_only) {
5649 prot = PROT_READ;
5650 } else {
5651 prot = PROT_READ | PROT_WRITE;
5652 }
5653
5654 if (allow_exec) {
5655 prot |= PROT_EXEC;
5656 }
5657
5658 if (addr != NULL) {
5659 flags |= MAP_FIXED;
5660 }
5661
5662 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5663 fd, file_offset);
5664 if (mapped_address == MAP_FAILED) {
5665 return NULL;
5666 }
5667 return mapped_address;
5668 }
5669
5670
5671 // Remap a block of memory.
5672 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5673 char *addr, size_t bytes, bool read_only,
5674 bool allow_exec) {
5675 // same as map_memory() on this OS
5676 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5677 allow_exec);
5678 }
5679
5680
5681 // Unmap a block of memory.
5682 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5683 return munmap(addr, bytes) == 0;
5684 }
5685
5686 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5687
5688 static jlong fast_cpu_time(Thread *thread) {
5689 clockid_t clockid;
5690 int rc = os::Linux::pthread_getcpuclockid(thread->osthread()->pthread_id(),
5691 &clockid);
5692 if (rc == 0) {
5693 return os::Linux::fast_thread_cpu_time(clockid);
5694 } else {
5695 // It's possible to encounter a terminated native thread that failed
5696 // to detach itself from the VM - which should result in ESRCH.
5697 assert_status(rc == ESRCH, rc, "pthread_getcpuclockid failed");
5698 return -1;
5699 }
5700 }
5701
5702 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5703 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5704 // of a thread.
5705 //
5706 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5707 // the fast estimate available on the platform.
5708
5709 jlong os::current_thread_cpu_time() {
5710 if (os::Linux::supports_fast_thread_cpu_time()) {
5711 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5712 } else {
5713 // return user + sys since the cost is the same
5714 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5715 }
5716 }
5717
5718 jlong os::thread_cpu_time(Thread* thread) {
5719 // consistent with what current_thread_cpu_time() returns
5720 if (os::Linux::supports_fast_thread_cpu_time()) {
5721 return fast_cpu_time(thread);
5722 } else {
5723 return slow_thread_cpu_time(thread, true /* user + sys */);
5724 }
5725 }
5726
5727 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5728 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5729 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5730 } else {
5731 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5732 }
5733 }
5734
5735 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5736 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5737 return fast_cpu_time(thread);
5738 } else {
5739 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5740 }
5741 }
5742
5743 // -1 on error.
5744 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5745 pid_t tid = thread->osthread()->thread_id();
5746 char *s;
5747 char stat[2048];
5748 int statlen;
5749 char proc_name[64];
5750 int count;
5751 long sys_time, user_time;
5752 char cdummy;
5753 int idummy;
5754 long ldummy;
5755 FILE *fp;
5756
5757 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5758 fp = fopen(proc_name, "r");
5759 if (fp == NULL) return -1;
5760 statlen = fread(stat, 1, 2047, fp);
5761 stat[statlen] = '\0';
5762 fclose(fp);
5763
5764 // Skip pid and the command string. Note that we could be dealing with
5765 // weird command names, e.g. user could decide to rename java launcher
5766 // to "java 1.4.2 :)", then the stat file would look like
5767 // 1234 (java 1.4.2 :)) R ... ...
5768 // We don't really need to know the command string, just find the last
5769 // occurrence of ")" and then start parsing from there. See bug 4726580.
5770 s = strrchr(stat, ')');
5771 if (s == NULL) return -1;
5772
5773 // Skip blank chars
5774 do { s++; } while (s && isspace(*s));
5775
5776 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5777 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5778 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5779 &user_time, &sys_time);
5780 if (count != 13) return -1;
5781 if (user_sys_cpu_time) {
5782 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5783 } else {
5784 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5785 }
5786 }
5787
5788 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5789 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5790 info_ptr->may_skip_backward = false; // elapsed time not wall time
5791 info_ptr->may_skip_forward = false; // elapsed time not wall time
5792 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5793 }
5794
5795 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5796 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5797 info_ptr->may_skip_backward = false; // elapsed time not wall time
5798 info_ptr->may_skip_forward = false; // elapsed time not wall time
5799 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5800 }
5801
5802 bool os::is_thread_cpu_time_supported() {
5803 return true;
5804 }
5805
5806 // System loadavg support. Returns -1 if load average cannot be obtained.
5807 // Linux doesn't yet have a (official) notion of processor sets,
5808 // so just return the system wide load average.
5809 int os::loadavg(double loadavg[], int nelem) {
5810 return ::getloadavg(loadavg, nelem);
5811 }
5812
5813 void os::pause() {
5814 char filename[MAX_PATH];
5815 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5816 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5817 } else {
5818 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5819 }
5820
5821 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5822 if (fd != -1) {
5823 struct stat buf;
5824 ::close(fd);
5825 while (::stat(filename, &buf) == 0) {
5826 (void)::poll(NULL, 0, 100);
5827 }
5828 } else {
5829 jio_fprintf(stderr,
5830 "Could not open pause file '%s', continuing immediately.\n", filename);
5831 }
5832 }
5833
5834 extern char** environ;
5835
5836 // Run the specified command in a separate process. Return its exit value,
5837 // or -1 on failure (e.g. can't fork a new process).
5838 // Unlike system(), this function can be called from signal handler. It
5839 // doesn't block SIGINT et al.
5840 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
5841 const char * argv[4] = {"sh", "-c", cmd, NULL};
5842
5843 pid_t pid ;
5844
5845 if (use_vfork_if_available) {
5846 pid = vfork();
5847 } else {
5848 pid = fork();
5849 }
5850
5851 if (pid < 0) {
5852 // fork failed
5853 return -1;
5854
5855 } else if (pid == 0) {
5856 // child process
5857
5858 execve("/bin/sh", (char* const*)argv, environ);
5859
5860 // execve failed
5861 _exit(-1);
5862
5863 } else {
5864 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5865 // care about the actual exit code, for now.
5866
5867 int status;
5868
5869 // Wait for the child process to exit. This returns immediately if
5870 // the child has already exited. */
5871 while (waitpid(pid, &status, 0) < 0) {
5872 switch (errno) {
5873 case ECHILD: return 0;
5874 case EINTR: break;
5875 default: return -1;
5876 }
5877 }
5878
5879 if (WIFEXITED(status)) {
5880 // The child exited normally; get its exit code.
5881 return WEXITSTATUS(status);
5882 } else if (WIFSIGNALED(status)) {
5883 // The child exited because of a signal
5884 // The best value to return is 0x80 + signal number,
5885 // because that is what all Unix shells do, and because
5886 // it allows callers to distinguish between process exit and
5887 // process death by signal.
5888 return 0x80 + WTERMSIG(status);
5889 } else {
5890 // Unknown exit code; pass it through
5891 return status;
5892 }
5893 }
5894 }
5895
5896 // Get the default path to the core file
5897 // Returns the length of the string
5898 int os::get_core_path(char* buffer, size_t bufferSize) {
5899 /*
5900 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5901 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5902 */
5903 const int core_pattern_len = 129;
5904 char core_pattern[core_pattern_len] = {0};
5905
5906 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5907 if (core_pattern_file == -1) {
5908 return -1;
5909 }
5910
5911 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5912 ::close(core_pattern_file);
5913 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5914 return -1;
5915 }
5916 if (core_pattern[ret-1] == '\n') {
5917 core_pattern[ret-1] = '\0';
5918 } else {
5919 core_pattern[ret] = '\0';
5920 }
5921
5922 // Replace the %p in the core pattern with the process id. NOTE: we do this
5923 // only if the pattern doesn't start with "|", and we support only one %p in
5924 // the pattern.
5925 char *pid_pos = strstr(core_pattern, "%p");
5926 const char* tail = (pid_pos != NULL) ? (pid_pos + 2) : ""; // skip over the "%p"
5927 int written;
5928
5929 if (core_pattern[0] == '/') {
5930 if (pid_pos != NULL) {
5931 *pid_pos = '\0';
5932 written = jio_snprintf(buffer, bufferSize, "%s%d%s", core_pattern,
5933 current_process_id(), tail);
5934 } else {
5935 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5936 }
5937 } else {
5938 char cwd[PATH_MAX];
5939
5940 const char* p = get_current_directory(cwd, PATH_MAX);
5941 if (p == NULL) {
5942 return -1;
5943 }
5944
5945 if (core_pattern[0] == '|') {
5946 written = jio_snprintf(buffer, bufferSize,
5947 "\"%s\" (or dumping to %s/core.%d)",
5948 &core_pattern[1], p, current_process_id());
5949 } else if (pid_pos != NULL) {
5950 *pid_pos = '\0';
5951 written = jio_snprintf(buffer, bufferSize, "%s/%s%d%s", p, core_pattern,
5952 current_process_id(), tail);
5953 } else {
5954 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5955 }
5956 }
5957
5958 if (written < 0) {
5959 return -1;
5960 }
5961
5962 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5963 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5964
5965 if (core_uses_pid_file != -1) {
5966 char core_uses_pid = 0;
5967 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5968 ::close(core_uses_pid_file);
5969
5970 if (core_uses_pid == '1') {
5971 jio_snprintf(buffer + written, bufferSize - written,
5972 ".%d", current_process_id());
5973 }
5974 }
5975 }
5976
5977 return strlen(buffer);
5978 }
5979
5980 bool os::start_debugging(char *buf, int buflen) {
5981 int len = (int)strlen(buf);
5982 char *p = &buf[len];
5983
5984 jio_snprintf(p, buflen-len,
5985 "\n\n"
5986 "Do you want to debug the problem?\n\n"
5987 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
5988 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
5989 "Otherwise, press RETURN to abort...",
5990 os::current_process_id(), os::current_process_id(),
5991 os::current_thread_id(), os::current_thread_id());
5992
5993 bool yes = os::message_box("Unexpected Error", buf);
5994
5995 if (yes) {
5996 // yes, user asked VM to launch debugger
5997 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
5998 os::current_process_id(), os::current_process_id());
5999
6000 os::fork_and_exec(buf);
6001 yes = false;
6002 }
6003 return yes;
6004 }
6005
6006
6007 // Java/Compiler thread:
6008 //
6009 // Low memory addresses
6010 // P0 +------------------------+
6011 // | |\ Java thread created by VM does not have glibc
6012 // | glibc guard page | - guard page, attached Java thread usually has
6013 // | |/ 1 glibc guard page.
6014 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6015 // | |\
6016 // | HotSpot Guard Pages | - red, yellow and reserved pages
6017 // | |/
6018 // +------------------------+ JavaThread::stack_reserved_zone_base()
6019 // | |\
6020 // | Normal Stack | -
6021 // | |/
6022 // P2 +------------------------+ Thread::stack_base()
6023 //
6024 // Non-Java thread:
6025 //
6026 // Low memory addresses
6027 // P0 +------------------------+
6028 // | |\
6029 // | glibc guard page | - usually 1 page
6030 // | |/
6031 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6032 // | |\
6033 // | Normal Stack | -
6034 // | |/
6035 // P2 +------------------------+ Thread::stack_base()
6036 //
6037 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6038 // returned from pthread_attr_getstack().
6039 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6040 // of the stack size given in pthread_attr. We work around this for
6041 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6042 //
6043 #ifndef ZERO
6044 static void current_stack_region(address * bottom, size_t * size) {
6045 if (os::is_primordial_thread()) {
6046 // primordial thread needs special handling because pthread_getattr_np()
6047 // may return bogus value.
6048 *bottom = os::Linux::initial_thread_stack_bottom();
6049 *size = os::Linux::initial_thread_stack_size();
6050 } else {
6051 pthread_attr_t attr;
6052
6053 int rslt = pthread_getattr_np(pthread_self(), &attr);
6054
6055 // JVM needs to know exact stack location, abort if it fails
6056 if (rslt != 0) {
6057 if (rslt == ENOMEM) {
6058 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6059 } else {
6060 fatal("pthread_getattr_np failed with error = %d", rslt);
6061 }
6062 }
6063
6064 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6065 fatal("Cannot locate current stack attributes!");
6066 }
6067
6068 // Work around NPTL stack guard error.
6069 size_t guard_size = 0;
6070 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6071 if (rslt != 0) {
6072 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6073 }
6074 *bottom += guard_size;
6075 *size -= guard_size;
6076
6077 pthread_attr_destroy(&attr);
6078
6079 }
6080 assert(os::current_stack_pointer() >= *bottom &&
6081 os::current_stack_pointer() < *bottom + *size, "just checking");
6082 }
6083
6084 address os::current_stack_base() {
6085 address bottom;
6086 size_t size;
6087 current_stack_region(&bottom, &size);
6088 return (bottom + size);
6089 }
6090
6091 size_t os::current_stack_size() {
6092 // This stack size includes the usable stack and HotSpot guard pages
6093 // (for the threads that have Hotspot guard pages).
6094 address bottom;
6095 size_t size;
6096 current_stack_region(&bottom, &size);
6097 return size;
6098 }
6099 #endif
6100
6101 static inline struct timespec get_mtime(const char* filename) {
6102 struct stat st;
6103 int ret = os::stat(filename, &st);
6104 assert(ret == 0, "failed to stat() file '%s': %s", filename, os::strerror(errno));
6105 return st.st_mtim;
6106 }
6107
6108 int os::compare_file_modified_times(const char* file1, const char* file2) {
6109 struct timespec filetime1 = get_mtime(file1);
6110 struct timespec filetime2 = get_mtime(file2);
6111 int diff = filetime1.tv_sec - filetime2.tv_sec;
6112 if (diff == 0) {
6113 return filetime1.tv_nsec - filetime2.tv_nsec;
6114 }
6115 return diff;
6116 }
6117
6118 /////////////// Unit tests ///////////////
6119
6120 #ifndef PRODUCT
6121
6122 class TestReserveMemorySpecial : AllStatic {
6123 public:
6124 static void small_page_write(void* addr, size_t size) {
6125 size_t page_size = os::vm_page_size();
6126
6127 char* end = (char*)addr + size;
6128 for (char* p = (char*)addr; p < end; p += page_size) {
6129 *p = 1;
6130 }
6131 }
6132
6133 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6134 if (!UseHugeTLBFS) {
6135 return;
6136 }
6137
6138 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6139
6140 if (addr != NULL) {
6141 small_page_write(addr, size);
6142
6143 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6144 }
6145 }
6146
6147 static void test_reserve_memory_special_huge_tlbfs_only() {
6148 if (!UseHugeTLBFS) {
6149 return;
6150 }
6151
6152 size_t lp = os::large_page_size();
6153
6154 for (size_t size = lp; size <= lp * 10; size += lp) {
6155 test_reserve_memory_special_huge_tlbfs_only(size);
6156 }
6157 }
6158
6159 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6160 size_t lp = os::large_page_size();
6161 size_t ag = os::vm_allocation_granularity();
6162
6163 // sizes to test
6164 const size_t sizes[] = {
6165 lp, lp + ag, lp + lp / 2, lp * 2,
6166 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6167 lp * 10, lp * 10 + lp / 2
6168 };
6169 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6170
6171 // For each size/alignment combination, we test three scenarios:
6172 // 1) with req_addr == NULL
6173 // 2) with a non-null req_addr at which we expect to successfully allocate
6174 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6175 // expect the allocation to either fail or to ignore req_addr
6176
6177 // Pre-allocate two areas; they shall be as large as the largest allocation
6178 // and aligned to the largest alignment we will be testing.
6179 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6180 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6181 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6182 -1, 0);
6183 assert(mapping1 != MAP_FAILED, "should work");
6184
6185 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6186 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6187 -1, 0);
6188 assert(mapping2 != MAP_FAILED, "should work");
6189
6190 // Unmap the first mapping, but leave the second mapping intact: the first
6191 // mapping will serve as a value for a "good" req_addr (case 2). The second
6192 // mapping, still intact, as "bad" req_addr (case 3).
6193 ::munmap(mapping1, mapping_size);
6194
6195 // Case 1
6196 for (int i = 0; i < num_sizes; i++) {
6197 const size_t size = sizes[i];
6198 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6199 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6200 if (p != NULL) {
6201 assert(is_aligned(p, alignment), "must be");
6202 small_page_write(p, size);
6203 os::Linux::release_memory_special_huge_tlbfs(p, size);
6204 }
6205 }
6206 }
6207
6208 // Case 2
6209 for (int i = 0; i < num_sizes; i++) {
6210 const size_t size = sizes[i];
6211 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6212 char* const req_addr = align_up(mapping1, alignment);
6213 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6214 if (p != NULL) {
6215 assert(p == req_addr, "must be");
6216 small_page_write(p, size);
6217 os::Linux::release_memory_special_huge_tlbfs(p, size);
6218 }
6219 }
6220 }
6221
6222 // Case 3
6223 for (int i = 0; i < num_sizes; i++) {
6224 const size_t size = sizes[i];
6225 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6226 char* const req_addr = align_up(mapping2, alignment);
6227 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6228 // as the area around req_addr contains already existing mappings, the API should always
6229 // return NULL (as per contract, it cannot return another address)
6230 assert(p == NULL, "must be");
6231 }
6232 }
6233
6234 ::munmap(mapping2, mapping_size);
6235
6236 }
6237
6238 static void test_reserve_memory_special_huge_tlbfs() {
6239 if (!UseHugeTLBFS) {
6240 return;
6241 }
6242
6243 test_reserve_memory_special_huge_tlbfs_only();
6244 test_reserve_memory_special_huge_tlbfs_mixed();
6245 }
6246
6247 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6248 if (!UseSHM) {
6249 return;
6250 }
6251
6252 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6253
6254 if (addr != NULL) {
6255 assert(is_aligned(addr, alignment), "Check");
6256 assert(is_aligned(addr, os::large_page_size()), "Check");
6257
6258 small_page_write(addr, size);
6259
6260 os::Linux::release_memory_special_shm(addr, size);
6261 }
6262 }
6263
6264 static void test_reserve_memory_special_shm() {
6265 size_t lp = os::large_page_size();
6266 size_t ag = os::vm_allocation_granularity();
6267
6268 for (size_t size = ag; size < lp * 3; size += ag) {
6269 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6270 test_reserve_memory_special_shm(size, alignment);
6271 }
6272 }
6273 }
6274
6275 static void test() {
6276 test_reserve_memory_special_huge_tlbfs();
6277 test_reserve_memory_special_shm();
6278 }
6279 };
6280
6281 void TestReserveMemorySpecial_test() {
6282 TestReserveMemorySpecial::test();
6283 }
6284
6285 #endif