1 /*
2 * Copyright (c) 1999, 2018, 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 "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_linux.inline.hpp"
40 #include "os_share_linux.hpp"
41 #include "osContainer_linux.hpp"
42 #include "prims/jniFastGetField.hpp"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/extendedPC.hpp"
47 #include "runtime/globals.hpp"
48 #include "runtime/interfaceSupport.inline.hpp"
49 #include "runtime/init.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "runtime/objectMonitor.hpp"
54 #include "runtime/orderAccess.inline.hpp"
55 #include "runtime/osThread.hpp"
56 #include "runtime/perfMemory.hpp"
57 #include "runtime/sharedRuntime.hpp"
58 #include "runtime/statSampler.hpp"
59 #include "runtime/stubRoutines.hpp"
60 #include "runtime/thread.inline.hpp"
61 #include "runtime/threadCritical.hpp"
62 #include "runtime/threadSMR.hpp"
63 #include "runtime/timer.hpp"
64 #include "semaphore_posix.hpp"
65 #include "services/attachListener.hpp"
66 #include "services/memTracker.hpp"
67 #include "services/runtimeService.hpp"
68 #include "utilities/align.hpp"
69 #include "utilities/decoder.hpp"
70 #include "utilities/defaultStream.hpp"
71 #include "utilities/events.hpp"
72 #include "utilities/elfFile.hpp"
73 #include "utilities/growableArray.hpp"
74 #include "utilities/macros.hpp"
75 #include "utilities/vmError.hpp"
76
77 // put OS-includes here
78 # include <sys/types.h>
79 # include <sys/mman.h>
80 # include <sys/stat.h>
81 # include <sys/select.h>
82 # include <pthread.h>
83 # include <signal.h>
84 # include <errno.h>
85 # include <dlfcn.h>
86 # include <stdio.h>
87 # include <unistd.h>
88 # include <sys/resource.h>
89 # include <pthread.h>
90 # include <sys/stat.h>
91 # include <sys/time.h>
92 # include <sys/times.h>
93 # include <sys/utsname.h>
94 # include <sys/socket.h>
95 # include <sys/wait.h>
96 # include <pwd.h>
97 # include <poll.h>
98 # include <fcntl.h>
99 # include <string.h>
100 # include <syscall.h>
101 # include <sys/sysinfo.h>
102 # include <gnu/libc-version.h>
103 # include <sys/ipc.h>
104 # include <sys/shm.h>
105 # include <link.h>
106 # include <stdint.h>
107 # include <inttypes.h>
108 # include <sys/ioctl.h>
109
110 #ifndef _GNU_SOURCE
111 #define _GNU_SOURCE
112 #include <sched.h>
113 #undef _GNU_SOURCE
114 #else
115 #include <sched.h>
116 #endif
117
118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
119 // getrusage() is prepared to handle the associated failure.
120 #ifndef RUSAGE_THREAD
121 #define RUSAGE_THREAD (1) /* only the calling thread */
122 #endif
123
124 #define MAX_PATH (2 * K)
125
126 #define MAX_SECS 100000000
127
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130
131 #define LARGEPAGES_BIT (1 << 6)
132 #define DAX_SHARED_BIT (1 << 8)
133 ////////////////////////////////////////////////////////////////////////////////
134 // global variables
135 julong os::Linux::_physical_memory = 0;
136
137 address os::Linux::_initial_thread_stack_bottom = NULL;
138 uintptr_t os::Linux::_initial_thread_stack_size = 0;
139
140 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
141 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
142 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
143 Mutex* os::Linux::_createThread_lock = NULL;
144 pthread_t os::Linux::_main_thread;
145 int os::Linux::_page_size = -1;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 uint32_t os::Linux::_os_version = 0;
148 const char * os::Linux::_glibc_version = NULL;
149 const char * os::Linux::_libpthread_version = NULL;
150
151 static jlong initial_time_count=0;
152
153 static int clock_tics_per_sec = 100;
154
155 // If the VM might have been created on the primordial thread, we need to resolve the
156 // primordial thread stack bounds and check if the current thread might be the
157 // primordial thread in places. If we know that the primordial thread is never used,
158 // such as when the VM was created by one of the standard java launchers, we can
159 // avoid this
160 static bool suppress_primordial_thread_resolution = false;
161
162 // For diagnostics to print a message once. see run_periodic_checks
163 static sigset_t check_signal_done;
164 static bool check_signals = true;
165
166 // Signal number used to suspend/resume a thread
167
168 // do not use any signal number less than SIGSEGV, see 4355769
169 static int SR_signum = SIGUSR2;
170 sigset_t SR_sigset;
171
172 // utility functions
173
174 static int SR_initialize();
175
176 julong os::available_memory() {
177 return Linux::available_memory();
178 }
179
180 julong os::Linux::available_memory() {
181 // values in struct sysinfo are "unsigned long"
182 struct sysinfo si;
183 julong avail_mem;
184
185 if (OSContainer::is_containerized()) {
186 jlong mem_limit, mem_usage;
187 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
188 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
189 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
190 }
191 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
192 log_debug(os, container)("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
193 }
194 if (mem_limit > 0 && mem_usage > 0 ) {
195 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
196 log_trace(os)("available container memory: " JULONG_FORMAT, avail_mem);
197 return avail_mem;
198 }
199 }
200
201 sysinfo(&si);
202 avail_mem = (julong)si.freeram * si.mem_unit;
203 log_trace(os)("available memory: " JULONG_FORMAT, avail_mem);
204 return avail_mem;
205 }
206
207 julong os::physical_memory() {
208 jlong phys_mem = 0;
209 if (OSContainer::is_containerized()) {
210 jlong mem_limit;
211 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
212 log_trace(os)("total container memory: " JLONG_FORMAT, mem_limit);
213 return mem_limit;
214 }
215 log_debug(os, container)("container memory limit %s: " JLONG_FORMAT ", using host value",
216 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
217 }
218
219 phys_mem = Linux::physical_memory();
220 log_trace(os)("total system memory: " JLONG_FORMAT, phys_mem);
221 return phys_mem;
222 }
223
224 // Return true if user is running as root.
225
226 bool os::have_special_privileges() {
227 static bool init = false;
228 static bool privileges = false;
229 if (!init) {
230 privileges = (getuid() != geteuid()) || (getgid() != getegid());
231 init = true;
232 }
233 return privileges;
234 }
235
236
237 #ifndef SYS_gettid
238 // i386: 224, ia64: 1105, amd64: 186, sparc 143
239 #ifdef __ia64__
240 #define SYS_gettid 1105
241 #else
242 #ifdef __i386__
243 #define SYS_gettid 224
244 #else
245 #ifdef __amd64__
246 #define SYS_gettid 186
247 #else
248 #ifdef __sparc__
249 #define SYS_gettid 143
250 #else
251 #error define gettid for the arch
252 #endif
253 #endif
254 #endif
255 #endif
256 #endif
257
258
259 // pid_t gettid()
260 //
261 // Returns the kernel thread id of the currently running thread. Kernel
262 // thread id is used to access /proc.
263 pid_t os::Linux::gettid() {
264 int rslt = syscall(SYS_gettid);
265 assert(rslt != -1, "must be."); // old linuxthreads implementation?
266 return (pid_t)rslt;
267 }
268
269 // Most versions of linux have a bug where the number of processors are
270 // determined by looking at the /proc file system. In a chroot environment,
271 // the system call returns 1. This causes the VM to act as if it is
272 // a single processor and elide locking (see is_MP() call).
273 static bool unsafe_chroot_detected = false;
274 static const char *unstable_chroot_error = "/proc file system not found.\n"
275 "Java may be unstable running multithreaded in a chroot "
276 "environment on Linux when /proc filesystem is not mounted.";
277
278 void os::Linux::initialize_system_info() {
279 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
280 if (processor_count() == 1) {
281 pid_t pid = os::Linux::gettid();
282 char fname[32];
283 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
284 FILE *fp = fopen(fname, "r");
285 if (fp == NULL) {
286 unsafe_chroot_detected = true;
287 } else {
288 fclose(fp);
289 }
290 }
291 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
292 assert(processor_count() > 0, "linux error");
293 }
294
295 void os::init_system_properties_values() {
296 // The next steps are taken in the product version:
297 //
298 // Obtain the JAVA_HOME value from the location of libjvm.so.
299 // This library should be located at:
300 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
301 //
302 // If "/jre/lib/" appears at the right place in the path, then we
303 // assume libjvm.so is installed in a JDK and we use this path.
304 //
305 // Otherwise exit with message: "Could not create the Java virtual machine."
306 //
307 // The following extra steps are taken in the debugging version:
308 //
309 // If "/jre/lib/" does NOT appear at the right place in the path
310 // instead of exit check for $JAVA_HOME environment variable.
311 //
312 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
313 // then we append a fake suffix "hotspot/libjvm.so" to this path so
314 // it looks like libjvm.so is installed there
315 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
316 //
317 // Otherwise exit.
318 //
319 // Important note: if the location of libjvm.so changes this
320 // code needs to be changed accordingly.
321
322 // See ld(1):
323 // The linker uses the following search paths to locate required
324 // shared libraries:
325 // 1: ...
326 // ...
327 // 7: The default directories, normally /lib and /usr/lib.
328 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
329 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
330 #else
331 #define DEFAULT_LIBPATH "/lib:/usr/lib"
332 #endif
333
334 // Base path of extensions installed on the system.
335 #define SYS_EXT_DIR "/usr/java/packages"
336 #define EXTENSIONS_DIR "/lib/ext"
337
338 // Buffer that fits several sprintfs.
339 // Note that the space for the colon and the trailing null are provided
340 // by the nulls included by the sizeof operator.
341 const size_t bufsize =
342 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
343 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
344 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
345
346 // sysclasspath, java_home, dll_dir
347 {
348 char *pslash;
349 os::jvm_path(buf, bufsize);
350
351 // Found the full path to libjvm.so.
352 // Now cut the path to <java_home>/jre if we can.
353 pslash = strrchr(buf, '/');
354 if (pslash != NULL) {
355 *pslash = '\0'; // Get rid of /libjvm.so.
356 }
357 pslash = strrchr(buf, '/');
358 if (pslash != NULL) {
359 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
360 }
361 Arguments::set_dll_dir(buf);
362
363 if (pslash != NULL) {
364 pslash = strrchr(buf, '/');
365 if (pslash != NULL) {
366 *pslash = '\0'; // Get rid of /lib.
367 }
368 }
369 Arguments::set_java_home(buf);
370 set_boot_path('/', ':');
371 }
372
373 // Where to look for native libraries.
374 //
375 // Note: Due to a legacy implementation, most of the library path
376 // is set in the launcher. This was to accomodate linking restrictions
377 // on legacy Linux implementations (which are no longer supported).
378 // Eventually, all the library path setting will be done here.
379 //
380 // However, to prevent the proliferation of improperly built native
381 // libraries, the new path component /usr/java/packages is added here.
382 // Eventually, all the library path setting will be done here.
383 {
384 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
385 // should always exist (until the legacy problem cited above is
386 // addressed).
387 const char *v = ::getenv("LD_LIBRARY_PATH");
388 const char *v_colon = ":";
389 if (v == NULL) { v = ""; v_colon = ""; }
390 // That's +1 for the colon and +1 for the trailing '\0'.
391 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
392 strlen(v) + 1 +
393 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
394 mtInternal);
395 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
396 Arguments::set_library_path(ld_library_path);
397 FREE_C_HEAP_ARRAY(char, ld_library_path);
398 }
399
400 // Extensions directories.
401 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
402 Arguments::set_ext_dirs(buf);
403
404 FREE_C_HEAP_ARRAY(char, buf);
405
406 #undef DEFAULT_LIBPATH
407 #undef SYS_EXT_DIR
408 #undef EXTENSIONS_DIR
409 }
410
411 ////////////////////////////////////////////////////////////////////////////////
412 // breakpoint support
413
414 void os::breakpoint() {
415 BREAKPOINT;
416 }
417
418 extern "C" void breakpoint() {
419 // use debugger to set breakpoint here
420 }
421
422 ////////////////////////////////////////////////////////////////////////////////
423 // signal support
424
425 debug_only(static bool signal_sets_initialized = false);
426 static sigset_t unblocked_sigs, vm_sigs;
427
428 bool os::Linux::is_sig_ignored(int sig) {
429 struct sigaction oact;
430 sigaction(sig, (struct sigaction*)NULL, &oact);
431 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
432 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
433 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
434 return true;
435 } else {
436 return false;
437 }
438 }
439
440 void os::Linux::signal_sets_init() {
441 // Should also have an assertion stating we are still single-threaded.
442 assert(!signal_sets_initialized, "Already initialized");
443 // Fill in signals that are necessarily unblocked for all threads in
444 // the VM. Currently, we unblock the following signals:
445 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
446 // by -Xrs (=ReduceSignalUsage));
447 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
448 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
449 // the dispositions or masks wrt these signals.
450 // Programs embedding the VM that want to use the above signals for their
451 // own purposes must, at this time, use the "-Xrs" option to prevent
452 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
453 // (See bug 4345157, and other related bugs).
454 // In reality, though, unblocking these signals is really a nop, since
455 // these signals are not blocked by default.
456 sigemptyset(&unblocked_sigs);
457 sigaddset(&unblocked_sigs, SIGILL);
458 sigaddset(&unblocked_sigs, SIGSEGV);
459 sigaddset(&unblocked_sigs, SIGBUS);
460 sigaddset(&unblocked_sigs, SIGFPE);
461 #if defined(PPC64)
462 sigaddset(&unblocked_sigs, SIGTRAP);
463 #endif
464 sigaddset(&unblocked_sigs, SR_signum);
465
466 if (!ReduceSignalUsage) {
467 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
468 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
469 }
470 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
471 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
472 }
473 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
474 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
475 }
476 }
477 // Fill in signals that are blocked by all but the VM thread.
478 sigemptyset(&vm_sigs);
479 if (!ReduceSignalUsage) {
480 sigaddset(&vm_sigs, BREAK_SIGNAL);
481 }
482 debug_only(signal_sets_initialized = true);
483
484 }
485
486 // These are signals that are unblocked while a thread is running Java.
487 // (For some reason, they get blocked by default.)
488 sigset_t* os::Linux::unblocked_signals() {
489 assert(signal_sets_initialized, "Not initialized");
490 return &unblocked_sigs;
491 }
492
493 // These are the signals that are blocked while a (non-VM) thread is
494 // running Java. Only the VM thread handles these signals.
495 sigset_t* os::Linux::vm_signals() {
496 assert(signal_sets_initialized, "Not initialized");
497 return &vm_sigs;
498 }
499
500 void os::Linux::hotspot_sigmask(Thread* thread) {
501
502 //Save caller's signal mask before setting VM signal mask
503 sigset_t caller_sigmask;
504 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
505
506 OSThread* osthread = thread->osthread();
507 osthread->set_caller_sigmask(caller_sigmask);
508
509 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
510
511 if (!ReduceSignalUsage) {
512 if (thread->is_VM_thread()) {
513 // Only the VM thread handles BREAK_SIGNAL ...
514 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
515 } else {
516 // ... all other threads block BREAK_SIGNAL
517 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
518 }
519 }
520 }
521
522 //////////////////////////////////////////////////////////////////////////////
523 // detecting pthread library
524
525 void os::Linux::libpthread_init() {
526 // Save glibc and pthread version strings.
527 #if !defined(_CS_GNU_LIBC_VERSION) || \
528 !defined(_CS_GNU_LIBPTHREAD_VERSION)
529 #error "glibc too old (< 2.3.2)"
530 #endif
531
532 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
533 assert(n > 0, "cannot retrieve glibc version");
534 char *str = (char *)malloc(n, mtInternal);
535 confstr(_CS_GNU_LIBC_VERSION, str, n);
536 os::Linux::set_glibc_version(str);
537
538 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
539 assert(n > 0, "cannot retrieve pthread version");
540 str = (char *)malloc(n, mtInternal);
541 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
542 os::Linux::set_libpthread_version(str);
543 }
544
545 /////////////////////////////////////////////////////////////////////////////
546 // thread stack expansion
547
548 // os::Linux::manually_expand_stack() takes care of expanding the thread
549 // stack. Note that this is normally not needed: pthread stacks allocate
550 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
551 // committed. Therefore it is not necessary to expand the stack manually.
552 //
553 // Manually expanding the stack was historically needed on LinuxThreads
554 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
555 // it is kept to deal with very rare corner cases:
556 //
557 // For one, user may run the VM on an own implementation of threads
558 // whose stacks are - like the old LinuxThreads - implemented using
559 // mmap(MAP_GROWSDOWN).
560 //
561 // Also, this coding may be needed if the VM is running on the primordial
562 // thread. Normally we avoid running on the primordial thread; however,
563 // user may still invoke the VM on the primordial thread.
564 //
565 // The following historical comment describes the details about running
566 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
567
568
569 // Force Linux kernel to expand current thread stack. If "bottom" is close
570 // to the stack guard, caller should block all signals.
571 //
572 // MAP_GROWSDOWN:
573 // A special mmap() flag that is used to implement thread stacks. It tells
574 // kernel that the memory region should extend downwards when needed. This
575 // allows early versions of LinuxThreads to only mmap the first few pages
576 // when creating a new thread. Linux kernel will automatically expand thread
577 // stack as needed (on page faults).
578 //
579 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
580 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
581 // region, it's hard to tell if the fault is due to a legitimate stack
582 // access or because of reading/writing non-exist memory (e.g. buffer
583 // overrun). As a rule, if the fault happens below current stack pointer,
584 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
585 // application (see Linux kernel fault.c).
586 //
587 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
588 // stack overflow detection.
589 //
590 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
591 // not use MAP_GROWSDOWN.
592 //
593 // To get around the problem and allow stack banging on Linux, we need to
594 // manually expand thread stack after receiving the SIGSEGV.
595 //
596 // There are two ways to expand thread stack to address "bottom", we used
597 // both of them in JVM before 1.5:
598 // 1. adjust stack pointer first so that it is below "bottom", and then
599 // touch "bottom"
600 // 2. mmap() the page in question
601 //
602 // Now alternate signal stack is gone, it's harder to use 2. For instance,
603 // if current sp is already near the lower end of page 101, and we need to
604 // call mmap() to map page 100, it is possible that part of the mmap() frame
605 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
606 // That will destroy the mmap() frame and cause VM to crash.
607 //
608 // The following code works by adjusting sp first, then accessing the "bottom"
609 // page to force a page fault. Linux kernel will then automatically expand the
610 // stack mapping.
611 //
612 // _expand_stack_to() assumes its frame size is less than page size, which
613 // should always be true if the function is not inlined.
614
615 static void NOINLINE _expand_stack_to(address bottom) {
616 address sp;
617 size_t size;
618 volatile char *p;
619
620 // Adjust bottom to point to the largest address within the same page, it
621 // gives us a one-page buffer if alloca() allocates slightly more memory.
622 bottom = (address)align_down((uintptr_t)bottom, os::Linux::page_size());
623 bottom += os::Linux::page_size() - 1;
624
625 // sp might be slightly above current stack pointer; if that's the case, we
626 // will alloca() a little more space than necessary, which is OK. Don't use
627 // os::current_stack_pointer(), as its result can be slightly below current
628 // stack pointer, causing us to not alloca enough to reach "bottom".
629 sp = (address)&sp;
630
631 if (sp > bottom) {
632 size = sp - bottom;
633 p = (volatile char *)alloca(size);
634 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
635 p[0] = '\0';
636 }
637 }
638
639 void os::Linux::expand_stack_to(address bottom) {
640 _expand_stack_to(bottom);
641 }
642
643 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
644 assert(t!=NULL, "just checking");
645 assert(t->osthread()->expanding_stack(), "expand should be set");
646 assert(t->stack_base() != NULL, "stack_base was not initialized");
647
648 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
649 sigset_t mask_all, old_sigset;
650 sigfillset(&mask_all);
651 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
652 _expand_stack_to(addr);
653 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
654 return true;
655 }
656 return false;
657 }
658
659 //////////////////////////////////////////////////////////////////////////////
660 // create new thread
661
662 // Thread start routine for all newly created threads
663 static void *thread_native_entry(Thread *thread) {
664 // Try to randomize the cache line index of hot stack frames.
665 // This helps when threads of the same stack traces evict each other's
666 // cache lines. The threads can be either from the same JVM instance, or
667 // from different JVM instances. The benefit is especially true for
668 // processors with hyperthreading technology.
669 static int counter = 0;
670 int pid = os::current_process_id();
671 alloca(((pid ^ counter++) & 7) * 128);
672
673 thread->initialize_thread_current();
674
675 OSThread* osthread = thread->osthread();
676 Monitor* sync = osthread->startThread_lock();
677
678 osthread->set_thread_id(os::current_thread_id());
679
680 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
681 os::current_thread_id(), (uintx) pthread_self());
682
683 if (UseNUMA) {
684 int lgrp_id = os::numa_get_group_id();
685 if (lgrp_id != -1) {
686 thread->set_lgrp_id(lgrp_id);
687 }
688 }
689 // initialize signal mask for this thread
690 os::Linux::hotspot_sigmask(thread);
691
692 // initialize floating point control register
693 os::Linux::init_thread_fpu_state();
694
695 // handshaking with parent thread
696 {
697 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
698
699 // notify parent thread
700 osthread->set_state(INITIALIZED);
701 sync->notify_all();
702
703 // wait until os::start_thread()
704 while (osthread->get_state() == INITIALIZED) {
705 sync->wait(Mutex::_no_safepoint_check_flag);
706 }
707 }
708
709 // call one more level start routine
710 thread->run();
711
712 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
713 os::current_thread_id(), (uintx) pthread_self());
714
715 // If a thread has not deleted itself ("delete this") as part of its
716 // termination sequence, we have to ensure thread-local-storage is
717 // cleared before we actually terminate. No threads should ever be
718 // deleted asynchronously with respect to their termination.
719 if (Thread::current_or_null_safe() != NULL) {
720 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
721 thread->clear_thread_current();
722 }
723
724 return 0;
725 }
726
727 bool os::create_thread(Thread* thread, ThreadType thr_type,
728 size_t req_stack_size) {
729 assert(thread->osthread() == NULL, "caller responsible");
730
731 // Allocate the OSThread object
732 OSThread* osthread = new OSThread(NULL, NULL);
733 if (osthread == NULL) {
734 return false;
735 }
736
737 // set the correct thread state
738 osthread->set_thread_type(thr_type);
739
740 // Initial state is ALLOCATED but not INITIALIZED
741 osthread->set_state(ALLOCATED);
742
743 thread->set_osthread(osthread);
744
745 // init thread attributes
746 pthread_attr_t attr;
747 pthread_attr_init(&attr);
748 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
749
750 // Calculate stack size if it's not specified by caller.
751 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
752 // In the Linux NPTL pthread implementation the guard size mechanism
753 // is not implemented properly. The posix standard requires adding
754 // the size of the guard pages to the stack size, instead Linux
755 // takes the space out of 'stacksize'. Thus we adapt the requested
756 // stack_size by the size of the guard pages to mimick proper
757 // behaviour. However, be careful not to end up with a size
758 // of zero due to overflow. Don't add the guard page in that case.
759 size_t guard_size = os::Linux::default_guard_size(thr_type);
760 if (stack_size <= SIZE_MAX - guard_size) {
761 stack_size += guard_size;
762 }
763 assert(is_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
764
765 int status = pthread_attr_setstacksize(&attr, stack_size);
766 assert_status(status == 0, status, "pthread_attr_setstacksize");
767
768 // Configure glibc guard page.
769 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
770
771 ThreadState state;
772
773 {
774 pthread_t tid;
775 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
776
777 char buf[64];
778 if (ret == 0) {
779 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
780 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
781 } else {
782 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
783 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
784 }
785
786 pthread_attr_destroy(&attr);
787
788 if (ret != 0) {
789 // Need to clean up stuff we've allocated so far
790 thread->set_osthread(NULL);
791 delete osthread;
792 return false;
793 }
794
795 // Store pthread info into the OSThread
796 osthread->set_pthread_id(tid);
797
798 // Wait until child thread is either initialized or aborted
799 {
800 Monitor* sync_with_child = osthread->startThread_lock();
801 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
802 while ((state = osthread->get_state()) == ALLOCATED) {
803 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
804 }
805 }
806 }
807
808 // Aborted due to thread limit being reached
809 if (state == ZOMBIE) {
810 thread->set_osthread(NULL);
811 delete osthread;
812 return false;
813 }
814
815 // The thread is returned suspended (in state INITIALIZED),
816 // and is started higher up in the call chain
817 assert(state == INITIALIZED, "race condition");
818 return true;
819 }
820
821 /////////////////////////////////////////////////////////////////////////////
822 // attach existing thread
823
824 // bootstrap the main thread
825 bool os::create_main_thread(JavaThread* thread) {
826 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
827 return create_attached_thread(thread);
828 }
829
830 bool os::create_attached_thread(JavaThread* thread) {
831 #ifdef ASSERT
832 thread->verify_not_published();
833 #endif
834
835 // Allocate the OSThread object
836 OSThread* osthread = new OSThread(NULL, NULL);
837
838 if (osthread == NULL) {
839 return false;
840 }
841
842 // Store pthread info into the OSThread
843 osthread->set_thread_id(os::Linux::gettid());
844 osthread->set_pthread_id(::pthread_self());
845
846 // initialize floating point control register
847 os::Linux::init_thread_fpu_state();
848
849 // Initial thread state is RUNNABLE
850 osthread->set_state(RUNNABLE);
851
852 thread->set_osthread(osthread);
853
854 if (UseNUMA) {
855 int lgrp_id = os::numa_get_group_id();
856 if (lgrp_id != -1) {
857 thread->set_lgrp_id(lgrp_id);
858 }
859 }
860
861 if (os::is_primordial_thread()) {
862 // If current thread is primordial thread, its stack is mapped on demand,
863 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
864 // the entire stack region to avoid SEGV in stack banging.
865 // It is also useful to get around the heap-stack-gap problem on SuSE
866 // kernel (see 4821821 for details). We first expand stack to the top
867 // of yellow zone, then enable stack yellow zone (order is significant,
868 // enabling yellow zone first will crash JVM on SuSE Linux), so there
869 // is no gap between the last two virtual memory regions.
870
871 JavaThread *jt = (JavaThread *)thread;
872 address addr = jt->stack_reserved_zone_base();
873 assert(addr != NULL, "initialization problem?");
874 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
875
876 osthread->set_expanding_stack();
877 os::Linux::manually_expand_stack(jt, addr);
878 osthread->clear_expanding_stack();
879 }
880
881 // initialize signal mask for this thread
882 // and save the caller's signal mask
883 os::Linux::hotspot_sigmask(thread);
884
885 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
886 os::current_thread_id(), (uintx) pthread_self());
887
888 return true;
889 }
890
891 void os::pd_start_thread(Thread* thread) {
892 OSThread * osthread = thread->osthread();
893 assert(osthread->get_state() != INITIALIZED, "just checking");
894 Monitor* sync_with_child = osthread->startThread_lock();
895 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
896 sync_with_child->notify();
897 }
898
899 // Free Linux resources related to the OSThread
900 void os::free_thread(OSThread* osthread) {
901 assert(osthread != NULL, "osthread not set");
902
903 // We are told to free resources of the argument thread,
904 // but we can only really operate on the current thread.
905 assert(Thread::current()->osthread() == osthread,
906 "os::free_thread but not current thread");
907
908 #ifdef ASSERT
909 sigset_t current;
910 sigemptyset(¤t);
911 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
912 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
913 #endif
914
915 // Restore caller's signal mask
916 sigset_t sigmask = osthread->caller_sigmask();
917 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
918
919 delete osthread;
920 }
921
922 //////////////////////////////////////////////////////////////////////////////
923 // primordial thread
924
925 // Check if current thread is the primordial thread, similar to Solaris thr_main.
926 bool os::is_primordial_thread(void) {
927 if (suppress_primordial_thread_resolution) {
928 return false;
929 }
930 char dummy;
931 // If called before init complete, thread stack bottom will be null.
932 // Can be called if fatal error occurs before initialization.
933 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
934 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
935 os::Linux::initial_thread_stack_size() != 0,
936 "os::init did not locate primordial thread's stack region");
937 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
938 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
939 os::Linux::initial_thread_stack_size()) {
940 return true;
941 } else {
942 return false;
943 }
944 }
945
946 // Find the virtual memory area that contains addr
947 static bool find_vma(address addr, address* vma_low, address* vma_high) {
948 FILE *fp = fopen("/proc/self/maps", "r");
949 if (fp) {
950 address low, high;
951 while (!feof(fp)) {
952 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
953 if (low <= addr && addr < high) {
954 if (vma_low) *vma_low = low;
955 if (vma_high) *vma_high = high;
956 fclose(fp);
957 return true;
958 }
959 }
960 for (;;) {
961 int ch = fgetc(fp);
962 if (ch == EOF || ch == (int)'\n') break;
963 }
964 }
965 fclose(fp);
966 }
967 return false;
968 }
969
970 // Locate primordial thread stack. This special handling of primordial thread stack
971 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
972 // bogus value for the primordial process thread. While the launcher has created
973 // the VM in a new thread since JDK 6, we still have to allow for the use of the
974 // JNI invocation API from a primordial thread.
975 void os::Linux::capture_initial_stack(size_t max_size) {
976
977 // max_size is either 0 (which means accept OS default for thread stacks) or
978 // a user-specified value known to be at least the minimum needed. If we
979 // are actually on the primordial thread we can make it appear that we have a
980 // smaller max_size stack by inserting the guard pages at that location. But we
981 // cannot do anything to emulate a larger stack than what has been provided by
982 // the OS or threading library. In fact if we try to use a stack greater than
983 // what is set by rlimit then we will crash the hosting process.
984
985 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
986 // If this is "unlimited" then it will be a huge value.
987 struct rlimit rlim;
988 getrlimit(RLIMIT_STACK, &rlim);
989 size_t stack_size = rlim.rlim_cur;
990
991 // 6308388: a bug in ld.so will relocate its own .data section to the
992 // lower end of primordial stack; reduce ulimit -s value a little bit
993 // so we won't install guard page on ld.so's data section.
994 // But ensure we don't underflow the stack size - allow 1 page spare
995 if (stack_size >= (size_t)(3 * page_size())) {
996 stack_size -= 2 * page_size();
997 }
998
999 // Try to figure out where the stack base (top) is. This is harder.
1000 //
1001 // When an application is started, glibc saves the initial stack pointer in
1002 // a global variable "__libc_stack_end", which is then used by system
1003 // libraries. __libc_stack_end should be pretty close to stack top. The
1004 // variable is available since the very early days. However, because it is
1005 // a private interface, it could disappear in the future.
1006 //
1007 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1008 // to __libc_stack_end, it is very close to stack top, but isn't the real
1009 // stack top. Note that /proc may not exist if VM is running as a chroot
1010 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1011 // /proc/<pid>/stat could change in the future (though unlikely).
1012 //
1013 // We try __libc_stack_end first. If that doesn't work, look for
1014 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1015 // as a hint, which should work well in most cases.
1016
1017 uintptr_t stack_start;
1018
1019 // try __libc_stack_end first
1020 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1021 if (p && *p) {
1022 stack_start = *p;
1023 } else {
1024 // see if we can get the start_stack field from /proc/self/stat
1025 FILE *fp;
1026 int pid;
1027 char state;
1028 int ppid;
1029 int pgrp;
1030 int session;
1031 int nr;
1032 int tpgrp;
1033 unsigned long flags;
1034 unsigned long minflt;
1035 unsigned long cminflt;
1036 unsigned long majflt;
1037 unsigned long cmajflt;
1038 unsigned long utime;
1039 unsigned long stime;
1040 long cutime;
1041 long cstime;
1042 long prio;
1043 long nice;
1044 long junk;
1045 long it_real;
1046 uintptr_t start;
1047 uintptr_t vsize;
1048 intptr_t rss;
1049 uintptr_t rsslim;
1050 uintptr_t scodes;
1051 uintptr_t ecode;
1052 int i;
1053
1054 // Figure what the primordial thread stack base is. Code is inspired
1055 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1056 // followed by command name surrounded by parentheses, state, etc.
1057 char stat[2048];
1058 int statlen;
1059
1060 fp = fopen("/proc/self/stat", "r");
1061 if (fp) {
1062 statlen = fread(stat, 1, 2047, fp);
1063 stat[statlen] = '\0';
1064 fclose(fp);
1065
1066 // Skip pid and the command string. Note that we could be dealing with
1067 // weird command names, e.g. user could decide to rename java launcher
1068 // to "java 1.4.2 :)", then the stat file would look like
1069 // 1234 (java 1.4.2 :)) R ... ...
1070 // We don't really need to know the command string, just find the last
1071 // occurrence of ")" and then start parsing from there. See bug 4726580.
1072 char * s = strrchr(stat, ')');
1073
1074 i = 0;
1075 if (s) {
1076 // Skip blank chars
1077 do { s++; } while (s && isspace(*s));
1078
1079 #define _UFM UINTX_FORMAT
1080 #define _DFM INTX_FORMAT
1081
1082 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1083 // 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
1084 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,
1085 &state, // 3 %c
1086 &ppid, // 4 %d
1087 &pgrp, // 5 %d
1088 &session, // 6 %d
1089 &nr, // 7 %d
1090 &tpgrp, // 8 %d
1091 &flags, // 9 %lu
1092 &minflt, // 10 %lu
1093 &cminflt, // 11 %lu
1094 &majflt, // 12 %lu
1095 &cmajflt, // 13 %lu
1096 &utime, // 14 %lu
1097 &stime, // 15 %lu
1098 &cutime, // 16 %ld
1099 &cstime, // 17 %ld
1100 &prio, // 18 %ld
1101 &nice, // 19 %ld
1102 &junk, // 20 %ld
1103 &it_real, // 21 %ld
1104 &start, // 22 UINTX_FORMAT
1105 &vsize, // 23 UINTX_FORMAT
1106 &rss, // 24 INTX_FORMAT
1107 &rsslim, // 25 UINTX_FORMAT
1108 &scodes, // 26 UINTX_FORMAT
1109 &ecode, // 27 UINTX_FORMAT
1110 &stack_start); // 28 UINTX_FORMAT
1111 }
1112
1113 #undef _UFM
1114 #undef _DFM
1115
1116 if (i != 28 - 2) {
1117 assert(false, "Bad conversion from /proc/self/stat");
1118 // product mode - assume we are the primordial thread, good luck in the
1119 // embedded case.
1120 warning("Can't detect primordial thread stack location - bad conversion");
1121 stack_start = (uintptr_t) &rlim;
1122 }
1123 } else {
1124 // For some reason we can't open /proc/self/stat (for example, running on
1125 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1126 // most cases, so don't abort:
1127 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1128 stack_start = (uintptr_t) &rlim;
1129 }
1130 }
1131
1132 // Now we have a pointer (stack_start) very close to the stack top, the
1133 // next thing to do is to figure out the exact location of stack top. We
1134 // can find out the virtual memory area that contains stack_start by
1135 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1136 // and its upper limit is the real stack top. (again, this would fail if
1137 // running inside chroot, because /proc may not exist.)
1138
1139 uintptr_t stack_top;
1140 address low, high;
1141 if (find_vma((address)stack_start, &low, &high)) {
1142 // success, "high" is the true stack top. (ignore "low", because initial
1143 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1144 stack_top = (uintptr_t)high;
1145 } else {
1146 // failed, likely because /proc/self/maps does not exist
1147 warning("Can't detect primordial thread stack location - find_vma failed");
1148 // best effort: stack_start is normally within a few pages below the real
1149 // stack top, use it as stack top, and reduce stack size so we won't put
1150 // guard page outside stack.
1151 stack_top = stack_start;
1152 stack_size -= 16 * page_size();
1153 }
1154
1155 // stack_top could be partially down the page so align it
1156 stack_top = align_up(stack_top, page_size());
1157
1158 // Allowed stack value is minimum of max_size and what we derived from rlimit
1159 if (max_size > 0) {
1160 _initial_thread_stack_size = MIN2(max_size, stack_size);
1161 } else {
1162 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1163 // clamp it at 8MB as we do on Solaris
1164 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1165 }
1166 _initial_thread_stack_size = align_down(_initial_thread_stack_size, page_size());
1167 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1168
1169 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1170
1171 if (log_is_enabled(Info, os, thread)) {
1172 // See if we seem to be on primordial process thread
1173 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1174 uintptr_t(&rlim) < stack_top;
1175
1176 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1177 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1178 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1179 stack_top, intptr_t(_initial_thread_stack_bottom));
1180 }
1181 }
1182
1183 ////////////////////////////////////////////////////////////////////////////////
1184 // time support
1185
1186 // Time since start-up in seconds to a fine granularity.
1187 // Used by VMSelfDestructTimer and the MemProfiler.
1188 double os::elapsedTime() {
1189
1190 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1191 }
1192
1193 jlong os::elapsed_counter() {
1194 return javaTimeNanos() - initial_time_count;
1195 }
1196
1197 jlong os::elapsed_frequency() {
1198 return NANOSECS_PER_SEC; // nanosecond resolution
1199 }
1200
1201 bool os::supports_vtime() { return true; }
1202 bool os::enable_vtime() { return false; }
1203 bool os::vtime_enabled() { return false; }
1204
1205 double os::elapsedVTime() {
1206 struct rusage usage;
1207 int retval = getrusage(RUSAGE_THREAD, &usage);
1208 if (retval == 0) {
1209 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);
1210 } else {
1211 // better than nothing, but not much
1212 return elapsedTime();
1213 }
1214 }
1215
1216 jlong os::javaTimeMillis() {
1217 timeval time;
1218 int status = gettimeofday(&time, NULL);
1219 assert(status != -1, "linux error");
1220 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1221 }
1222
1223 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1224 timeval time;
1225 int status = gettimeofday(&time, NULL);
1226 assert(status != -1, "linux error");
1227 seconds = jlong(time.tv_sec);
1228 nanos = jlong(time.tv_usec) * 1000;
1229 }
1230
1231
1232 #ifndef CLOCK_MONOTONIC
1233 #define CLOCK_MONOTONIC (1)
1234 #endif
1235
1236 void os::Linux::clock_init() {
1237 // we do dlopen's in this particular order due to bug in linux
1238 // dynamical loader (see 6348968) leading to crash on exit
1239 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1240 if (handle == NULL) {
1241 handle = dlopen("librt.so", RTLD_LAZY);
1242 }
1243
1244 if (handle) {
1245 int (*clock_getres_func)(clockid_t, struct timespec*) =
1246 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1247 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1248 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1249 if (clock_getres_func && clock_gettime_func) {
1250 // See if monotonic clock is supported by the kernel. Note that some
1251 // early implementations simply return kernel jiffies (updated every
1252 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1253 // for nano time (though the monotonic property is still nice to have).
1254 // It's fixed in newer kernels, however clock_getres() still returns
1255 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1256 // resolution for now. Hopefully as people move to new kernels, this
1257 // won't be a problem.
1258 struct timespec res;
1259 struct timespec tp;
1260 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1261 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1262 // yes, monotonic clock is supported
1263 _clock_gettime = clock_gettime_func;
1264 return;
1265 } else {
1266 // close librt if there is no monotonic clock
1267 dlclose(handle);
1268 }
1269 }
1270 }
1271 warning("No monotonic clock was available - timed services may " \
1272 "be adversely affected if the time-of-day clock changes");
1273 }
1274
1275 #ifndef SYS_clock_getres
1276 #if defined(X86) || defined(PPC64) || defined(S390)
1277 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261)
1278 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1279 #else
1280 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1281 #define sys_clock_getres(x,y) -1
1282 #endif
1283 #else
1284 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1285 #endif
1286
1287 void os::Linux::fast_thread_clock_init() {
1288 if (!UseLinuxPosixThreadCPUClocks) {
1289 return;
1290 }
1291 clockid_t clockid;
1292 struct timespec tp;
1293 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1294 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1295
1296 // Switch to using fast clocks for thread cpu time if
1297 // the sys_clock_getres() returns 0 error code.
1298 // Note, that some kernels may support the current thread
1299 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1300 // returned by the pthread_getcpuclockid().
1301 // If the fast Posix clocks are supported then the sys_clock_getres()
1302 // must return at least tp.tv_sec == 0 which means a resolution
1303 // better than 1 sec. This is extra check for reliability.
1304
1305 if (pthread_getcpuclockid_func &&
1306 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1307 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1308 _supports_fast_thread_cpu_time = true;
1309 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1310 }
1311 }
1312
1313 jlong os::javaTimeNanos() {
1314 if (os::supports_monotonic_clock()) {
1315 struct timespec tp;
1316 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1317 assert(status == 0, "gettime error");
1318 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1319 return result;
1320 } else {
1321 timeval time;
1322 int status = gettimeofday(&time, NULL);
1323 assert(status != -1, "linux error");
1324 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1325 return 1000 * usecs;
1326 }
1327 }
1328
1329 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1330 if (os::supports_monotonic_clock()) {
1331 info_ptr->max_value = ALL_64_BITS;
1332
1333 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1334 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1335 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1336 } else {
1337 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1338 info_ptr->max_value = ALL_64_BITS;
1339
1340 // gettimeofday is a real time clock so it skips
1341 info_ptr->may_skip_backward = true;
1342 info_ptr->may_skip_forward = true;
1343 }
1344
1345 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1346 }
1347
1348 // Return the real, user, and system times in seconds from an
1349 // arbitrary fixed point in the past.
1350 bool os::getTimesSecs(double* process_real_time,
1351 double* process_user_time,
1352 double* process_system_time) {
1353 struct tms ticks;
1354 clock_t real_ticks = times(&ticks);
1355
1356 if (real_ticks == (clock_t) (-1)) {
1357 return false;
1358 } else {
1359 double ticks_per_second = (double) clock_tics_per_sec;
1360 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1361 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1362 *process_real_time = ((double) real_ticks) / ticks_per_second;
1363
1364 return true;
1365 }
1366 }
1367
1368
1369 char * os::local_time_string(char *buf, size_t buflen) {
1370 struct tm t;
1371 time_t long_time;
1372 time(&long_time);
1373 localtime_r(&long_time, &t);
1374 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1375 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1376 t.tm_hour, t.tm_min, t.tm_sec);
1377 return buf;
1378 }
1379
1380 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1381 return localtime_r(clock, res);
1382 }
1383
1384 ////////////////////////////////////////////////////////////////////////////////
1385 // runtime exit support
1386
1387 // Note: os::shutdown() might be called very early during initialization, or
1388 // called from signal handler. Before adding something to os::shutdown(), make
1389 // sure it is async-safe and can handle partially initialized VM.
1390 void os::shutdown() {
1391
1392 // allow PerfMemory to attempt cleanup of any persistent resources
1393 perfMemory_exit();
1394
1395 // needs to remove object in file system
1396 AttachListener::abort();
1397
1398 // flush buffered output, finish log files
1399 ostream_abort();
1400
1401 // Check for abort hook
1402 abort_hook_t abort_hook = Arguments::abort_hook();
1403 if (abort_hook != NULL) {
1404 abort_hook();
1405 }
1406
1407 }
1408
1409 // Note: os::abort() might be called very early during initialization, or
1410 // called from signal handler. Before adding something to os::abort(), make
1411 // sure it is async-safe and can handle partially initialized VM.
1412 void os::abort(bool dump_core, void* siginfo, const void* context) {
1413 os::shutdown();
1414 if (dump_core) {
1415 #ifndef PRODUCT
1416 fdStream out(defaultStream::output_fd());
1417 out.print_raw("Current thread is ");
1418 char buf[16];
1419 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1420 out.print_raw_cr(buf);
1421 out.print_raw_cr("Dumping core ...");
1422 #endif
1423 ::abort(); // dump core
1424 }
1425
1426 ::exit(1);
1427 }
1428
1429 // Die immediately, no exit hook, no abort hook, no cleanup.
1430 void os::die() {
1431 ::abort();
1432 }
1433
1434
1435 // This method is a copy of JDK's sysGetLastErrorString
1436 // from src/solaris/hpi/src/system_md.c
1437
1438 size_t os::lasterror(char *buf, size_t len) {
1439 if (errno == 0) return 0;
1440
1441 const char *s = os::strerror(errno);
1442 size_t n = ::strlen(s);
1443 if (n >= len) {
1444 n = len - 1;
1445 }
1446 ::strncpy(buf, s, n);
1447 buf[n] = '\0';
1448 return n;
1449 }
1450
1451 // thread_id is kernel thread id (similar to Solaris LWP id)
1452 intx os::current_thread_id() { return os::Linux::gettid(); }
1453 int os::current_process_id() {
1454 return ::getpid();
1455 }
1456
1457 // DLL functions
1458
1459 const char* os::dll_file_extension() { return ".so"; }
1460
1461 // This must be hard coded because it's the system's temporary
1462 // directory not the java application's temp directory, ala java.io.tmpdir.
1463 const char* os::get_temp_directory() { return "/tmp"; }
1464
1465 static bool file_exists(const char* filename) {
1466 struct stat statbuf;
1467 if (filename == NULL || strlen(filename) == 0) {
1468 return false;
1469 }
1470 return os::stat(filename, &statbuf) == 0;
1471 }
1472
1473 // check if addr is inside libjvm.so
1474 bool os::address_is_in_vm(address addr) {
1475 static address libjvm_base_addr;
1476 Dl_info dlinfo;
1477
1478 if (libjvm_base_addr == NULL) {
1479 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1480 libjvm_base_addr = (address)dlinfo.dli_fbase;
1481 }
1482 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1483 }
1484
1485 if (dladdr((void *)addr, &dlinfo) != 0) {
1486 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1487 }
1488
1489 return false;
1490 }
1491
1492 bool os::dll_address_to_function_name(address addr, char *buf,
1493 int buflen, int *offset,
1494 bool demangle) {
1495 // buf is not optional, but offset is optional
1496 assert(buf != NULL, "sanity check");
1497
1498 Dl_info dlinfo;
1499
1500 if (dladdr((void*)addr, &dlinfo) != 0) {
1501 // see if we have a matching symbol
1502 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1503 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1504 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1505 }
1506 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1507 return true;
1508 }
1509 // no matching symbol so try for just file info
1510 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1511 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1512 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1513 return true;
1514 }
1515 }
1516 }
1517
1518 buf[0] = '\0';
1519 if (offset != NULL) *offset = -1;
1520 return false;
1521 }
1522
1523 struct _address_to_library_name {
1524 address addr; // input : memory address
1525 size_t buflen; // size of fname
1526 char* fname; // output: library name
1527 address base; // library base addr
1528 };
1529
1530 static int address_to_library_name_callback(struct dl_phdr_info *info,
1531 size_t size, void *data) {
1532 int i;
1533 bool found = false;
1534 address libbase = NULL;
1535 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1536
1537 // iterate through all loadable segments
1538 for (i = 0; i < info->dlpi_phnum; i++) {
1539 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1540 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1541 // base address of a library is the lowest address of its loaded
1542 // segments.
1543 if (libbase == NULL || libbase > segbase) {
1544 libbase = segbase;
1545 }
1546 // see if 'addr' is within current segment
1547 if (segbase <= d->addr &&
1548 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1549 found = true;
1550 }
1551 }
1552 }
1553
1554 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1555 // so dll_address_to_library_name() can fall through to use dladdr() which
1556 // can figure out executable name from argv[0].
1557 if (found && info->dlpi_name && info->dlpi_name[0]) {
1558 d->base = libbase;
1559 if (d->fname) {
1560 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1561 }
1562 return 1;
1563 }
1564 return 0;
1565 }
1566
1567 bool os::dll_address_to_library_name(address addr, char* buf,
1568 int buflen, int* offset) {
1569 // buf is not optional, but offset is optional
1570 assert(buf != NULL, "sanity check");
1571
1572 Dl_info dlinfo;
1573 struct _address_to_library_name data;
1574
1575 // There is a bug in old glibc dladdr() implementation that it could resolve
1576 // to wrong library name if the .so file has a base address != NULL. Here
1577 // we iterate through the program headers of all loaded libraries to find
1578 // out which library 'addr' really belongs to. This workaround can be
1579 // removed once the minimum requirement for glibc is moved to 2.3.x.
1580 data.addr = addr;
1581 data.fname = buf;
1582 data.buflen = buflen;
1583 data.base = NULL;
1584 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1585
1586 if (rslt) {
1587 // buf already contains library name
1588 if (offset) *offset = addr - data.base;
1589 return true;
1590 }
1591 if (dladdr((void*)addr, &dlinfo) != 0) {
1592 if (dlinfo.dli_fname != NULL) {
1593 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1594 }
1595 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1596 *offset = addr - (address)dlinfo.dli_fbase;
1597 }
1598 return true;
1599 }
1600
1601 buf[0] = '\0';
1602 if (offset) *offset = -1;
1603 return false;
1604 }
1605
1606 // Loads .dll/.so and
1607 // in case of error it checks if .dll/.so was built for the
1608 // same architecture as Hotspot is running on
1609
1610
1611 // Remember the stack's state. The Linux dynamic linker will change
1612 // the stack to 'executable' at most once, so we must safepoint only once.
1613 bool os::Linux::_stack_is_executable = false;
1614
1615 // VM operation that loads a library. This is necessary if stack protection
1616 // of the Java stacks can be lost during loading the library. If we
1617 // do not stop the Java threads, they can stack overflow before the stacks
1618 // are protected again.
1619 class VM_LinuxDllLoad: public VM_Operation {
1620 private:
1621 const char *_filename;
1622 char *_ebuf;
1623 int _ebuflen;
1624 void *_lib;
1625 public:
1626 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1627 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1628 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1629 void doit() {
1630 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1631 os::Linux::_stack_is_executable = true;
1632 }
1633 void* loaded_library() { return _lib; }
1634 };
1635
1636 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1637 void * result = NULL;
1638 bool load_attempted = false;
1639
1640 // Check whether the library to load might change execution rights
1641 // of the stack. If they are changed, the protection of the stack
1642 // guard pages will be lost. We need a safepoint to fix this.
1643 //
1644 // See Linux man page execstack(8) for more info.
1645 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1646 if (!ElfFile::specifies_noexecstack(filename)) {
1647 if (!is_init_completed()) {
1648 os::Linux::_stack_is_executable = true;
1649 // This is OK - No Java threads have been created yet, and hence no
1650 // stack guard pages to fix.
1651 //
1652 // This should happen only when you are building JDK7 using a very
1653 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1654 //
1655 // Dynamic loader will make all stacks executable after
1656 // this function returns, and will not do that again.
1657 assert(Threads::number_of_threads() == 0, "no Java threads should exist yet.");
1658 } else {
1659 warning("You have loaded library %s which might have disabled stack guard. "
1660 "The VM will try to fix the stack guard now.\n"
1661 "It's highly recommended that you fix the library with "
1662 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1663 filename);
1664
1665 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1666 JavaThread *jt = JavaThread::current();
1667 if (jt->thread_state() != _thread_in_native) {
1668 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1669 // that requires ExecStack. Cannot enter safe point. Let's give up.
1670 warning("Unable to fix stack guard. Giving up.");
1671 } else {
1672 if (!LoadExecStackDllInVMThread) {
1673 // This is for the case where the DLL has an static
1674 // constructor function that executes JNI code. We cannot
1675 // load such DLLs in the VMThread.
1676 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1677 }
1678
1679 ThreadInVMfromNative tiv(jt);
1680 debug_only(VMNativeEntryWrapper vew;)
1681
1682 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1683 VMThread::execute(&op);
1684 if (LoadExecStackDllInVMThread) {
1685 result = op.loaded_library();
1686 }
1687 load_attempted = true;
1688 }
1689 }
1690 }
1691 }
1692
1693 if (!load_attempted) {
1694 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1695 }
1696
1697 if (result != NULL) {
1698 // Successful loading
1699 return result;
1700 }
1701
1702 Elf32_Ehdr elf_head;
1703 int diag_msg_max_length=ebuflen-strlen(ebuf);
1704 char* diag_msg_buf=ebuf+strlen(ebuf);
1705
1706 if (diag_msg_max_length==0) {
1707 // No more space in ebuf for additional diagnostics message
1708 return NULL;
1709 }
1710
1711
1712 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1713
1714 if (file_descriptor < 0) {
1715 // Can't open library, report dlerror() message
1716 return NULL;
1717 }
1718
1719 bool failed_to_read_elf_head=
1720 (sizeof(elf_head)!=
1721 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1722
1723 ::close(file_descriptor);
1724 if (failed_to_read_elf_head) {
1725 // file i/o error - report dlerror() msg
1726 return NULL;
1727 }
1728
1729 typedef struct {
1730 Elf32_Half code; // Actual value as defined in elf.h
1731 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1732 unsigned char elf_class; // 32 or 64 bit
1733 unsigned char endianess; // MSB or LSB
1734 char* name; // String representation
1735 } arch_t;
1736
1737 #ifndef EM_486
1738 #define EM_486 6 /* Intel 80486 */
1739 #endif
1740 #ifndef EM_AARCH64
1741 #define EM_AARCH64 183 /* ARM AARCH64 */
1742 #endif
1743
1744 static const arch_t arch_array[]={
1745 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1746 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1747 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1748 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1749 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1750 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1751 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1752 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1753 #if defined(VM_LITTLE_ENDIAN)
1754 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1755 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SuperH"},
1756 #else
1757 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1758 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2MSB, (char*)"SuperH BE"},
1759 #endif
1760 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1761 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1762 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1763 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1764 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1765 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1766 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1767 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1768 };
1769
1770 #if (defined IA32)
1771 static Elf32_Half running_arch_code=EM_386;
1772 #elif (defined AMD64)
1773 static Elf32_Half running_arch_code=EM_X86_64;
1774 #elif (defined IA64)
1775 static Elf32_Half running_arch_code=EM_IA_64;
1776 #elif (defined __sparc) && (defined _LP64)
1777 static Elf32_Half running_arch_code=EM_SPARCV9;
1778 #elif (defined __sparc) && (!defined _LP64)
1779 static Elf32_Half running_arch_code=EM_SPARC;
1780 #elif (defined __powerpc64__)
1781 static Elf32_Half running_arch_code=EM_PPC64;
1782 #elif (defined __powerpc__)
1783 static Elf32_Half running_arch_code=EM_PPC;
1784 #elif (defined AARCH64)
1785 static Elf32_Half running_arch_code=EM_AARCH64;
1786 #elif (defined ARM)
1787 static Elf32_Half running_arch_code=EM_ARM;
1788 #elif (defined S390)
1789 static Elf32_Half running_arch_code=EM_S390;
1790 #elif (defined ALPHA)
1791 static Elf32_Half running_arch_code=EM_ALPHA;
1792 #elif (defined MIPSEL)
1793 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1794 #elif (defined PARISC)
1795 static Elf32_Half running_arch_code=EM_PARISC;
1796 #elif (defined MIPS)
1797 static Elf32_Half running_arch_code=EM_MIPS;
1798 #elif (defined M68K)
1799 static Elf32_Half running_arch_code=EM_68K;
1800 #elif (defined SH)
1801 static Elf32_Half running_arch_code=EM_SH;
1802 #else
1803 #error Method os::dll_load requires that one of following is defined:\
1804 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, SH, __sparc
1805 #endif
1806
1807 // Identify compatability class for VM's architecture and library's architecture
1808 // Obtain string descriptions for architectures
1809
1810 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1811 int running_arch_index=-1;
1812
1813 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1814 if (running_arch_code == arch_array[i].code) {
1815 running_arch_index = i;
1816 }
1817 if (lib_arch.code == arch_array[i].code) {
1818 lib_arch.compat_class = arch_array[i].compat_class;
1819 lib_arch.name = arch_array[i].name;
1820 }
1821 }
1822
1823 assert(running_arch_index != -1,
1824 "Didn't find running architecture code (running_arch_code) in arch_array");
1825 if (running_arch_index == -1) {
1826 // Even though running architecture detection failed
1827 // we may still continue with reporting dlerror() message
1828 return NULL;
1829 }
1830
1831 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1832 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1833 return NULL;
1834 }
1835
1836 #ifndef S390
1837 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1838 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1839 return NULL;
1840 }
1841 #endif // !S390
1842
1843 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1844 if (lib_arch.name!=NULL) {
1845 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1846 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1847 lib_arch.name, arch_array[running_arch_index].name);
1848 } else {
1849 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1850 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1851 lib_arch.code,
1852 arch_array[running_arch_index].name);
1853 }
1854 }
1855
1856 return NULL;
1857 }
1858
1859 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1860 int ebuflen) {
1861 void * result = ::dlopen(filename, RTLD_LAZY);
1862 if (result == NULL) {
1863 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1864 ebuf[ebuflen-1] = '\0';
1865 }
1866 return result;
1867 }
1868
1869 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1870 int ebuflen) {
1871 void * result = NULL;
1872 if (LoadExecStackDllInVMThread) {
1873 result = dlopen_helper(filename, ebuf, ebuflen);
1874 }
1875
1876 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1877 // library that requires an executable stack, or which does not have this
1878 // stack attribute set, dlopen changes the stack attribute to executable. The
1879 // read protection of the guard pages gets lost.
1880 //
1881 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1882 // may have been queued at the same time.
1883
1884 if (!_stack_is_executable) {
1885 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
1886 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1887 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1888 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1889 warning("Attempt to reguard stack yellow zone failed.");
1890 }
1891 }
1892 }
1893 }
1894
1895 return result;
1896 }
1897
1898 void* os::dll_lookup(void* handle, const char* name) {
1899 void* res = dlsym(handle, name);
1900 return res;
1901 }
1902
1903 void* os::get_default_process_handle() {
1904 return (void*)::dlopen(NULL, RTLD_LAZY);
1905 }
1906
1907 static bool _print_ascii_file(const char* filename, outputStream* st) {
1908 int fd = ::open(filename, O_RDONLY);
1909 if (fd == -1) {
1910 return false;
1911 }
1912
1913 char buf[33];
1914 int bytes;
1915 buf[32] = '\0';
1916 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1917 st->print_raw(buf, bytes);
1918 }
1919
1920 ::close(fd);
1921
1922 return true;
1923 }
1924
1925 void os::print_dll_info(outputStream *st) {
1926 st->print_cr("Dynamic libraries:");
1927
1928 char fname[32];
1929 pid_t pid = os::Linux::gettid();
1930
1931 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1932
1933 if (!_print_ascii_file(fname, st)) {
1934 st->print("Can not get library information for pid = %d\n", pid);
1935 }
1936 }
1937
1938 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1939 FILE *procmapsFile = NULL;
1940
1941 // Open the procfs maps file for the current process
1942 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1943 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1944 char line[PATH_MAX + 100];
1945
1946 // Read line by line from 'file'
1947 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1948 u8 base, top, offset, inode;
1949 char permissions[5];
1950 char device[6];
1951 char name[PATH_MAX + 1];
1952
1953 // Parse fields from line
1954 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1955 &base, &top, permissions, &offset, device, &inode, name);
1956
1957 // Filter by device id '00:00' so that we only get file system mapped files.
1958 if (strcmp(device, "00:00") != 0) {
1959
1960 // Call callback with the fields of interest
1961 if(callback(name, (address)base, (address)top, param)) {
1962 // Oops abort, callback aborted
1963 fclose(procmapsFile);
1964 return 1;
1965 }
1966 }
1967 }
1968 fclose(procmapsFile);
1969 }
1970 return 0;
1971 }
1972
1973 void os::print_os_info_brief(outputStream* st) {
1974 os::Linux::print_distro_info(st);
1975
1976 os::Posix::print_uname_info(st);
1977
1978 os::Linux::print_libversion_info(st);
1979
1980 }
1981
1982 void os::print_os_info(outputStream* st) {
1983 st->print("OS:");
1984
1985 os::Linux::print_distro_info(st);
1986
1987 os::Posix::print_uname_info(st);
1988
1989 // Print warning if unsafe chroot environment detected
1990 if (unsafe_chroot_detected) {
1991 st->print("WARNING!! ");
1992 st->print_cr("%s", unstable_chroot_error);
1993 }
1994
1995 os::Linux::print_libversion_info(st);
1996
1997 os::Posix::print_rlimit_info(st);
1998
1999 os::Posix::print_load_average(st);
2000
2001 os::Linux::print_full_memory_info(st);
2002
2003 os::Linux::print_container_info(st);
2004 }
2005
2006 // Try to identify popular distros.
2007 // Most Linux distributions have a /etc/XXX-release file, which contains
2008 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2009 // file that also contains the OS version string. Some have more than one
2010 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2011 // /etc/redhat-release.), so the order is important.
2012 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2013 // their own specific XXX-release file as well as a redhat-release file.
2014 // Because of this the XXX-release file needs to be searched for before the
2015 // redhat-release file.
2016 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2017 // search for redhat-release / SuSE-release needs to be before lsb-release.
2018 // Since the lsb-release file is the new standard it needs to be searched
2019 // before the older style release files.
2020 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2021 // next to last resort. The os-release file is a new standard that contains
2022 // distribution information and the system-release file seems to be an old
2023 // standard that has been replaced by the lsb-release and os-release files.
2024 // Searching for the debian_version file is the last resort. It contains
2025 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2026 // "Debian " is printed before the contents of the debian_version file.
2027
2028 const char* distro_files[] = {
2029 "/etc/oracle-release",
2030 "/etc/mandriva-release",
2031 "/etc/mandrake-release",
2032 "/etc/sun-release",
2033 "/etc/redhat-release",
2034 "/etc/SuSE-release",
2035 "/etc/lsb-release",
2036 "/etc/turbolinux-release",
2037 "/etc/gentoo-release",
2038 "/etc/ltib-release",
2039 "/etc/angstrom-version",
2040 "/etc/system-release",
2041 "/etc/os-release",
2042 NULL };
2043
2044 void os::Linux::print_distro_info(outputStream* st) {
2045 for (int i = 0;; i++) {
2046 const char* file = distro_files[i];
2047 if (file == NULL) {
2048 break; // done
2049 }
2050 // If file prints, we found it.
2051 if (_print_ascii_file(file, st)) {
2052 return;
2053 }
2054 }
2055
2056 if (file_exists("/etc/debian_version")) {
2057 st->print("Debian ");
2058 _print_ascii_file("/etc/debian_version", st);
2059 } else {
2060 st->print("Linux");
2061 }
2062 st->cr();
2063 }
2064
2065 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2066 char buf[256];
2067 while (fgets(buf, sizeof(buf), fp)) {
2068 // Edit out extra stuff in expected format
2069 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2070 char* ptr = strstr(buf, "\""); // the name is in quotes
2071 if (ptr != NULL) {
2072 ptr++; // go beyond first quote
2073 char* nl = strchr(ptr, '\"');
2074 if (nl != NULL) *nl = '\0';
2075 strncpy(distro, ptr, length);
2076 } else {
2077 ptr = strstr(buf, "=");
2078 ptr++; // go beyond equals then
2079 char* nl = strchr(ptr, '\n');
2080 if (nl != NULL) *nl = '\0';
2081 strncpy(distro, ptr, length);
2082 }
2083 return;
2084 } else if (get_first_line) {
2085 char* nl = strchr(buf, '\n');
2086 if (nl != NULL) *nl = '\0';
2087 strncpy(distro, buf, length);
2088 return;
2089 }
2090 }
2091 // print last line and close
2092 char* nl = strchr(buf, '\n');
2093 if (nl != NULL) *nl = '\0';
2094 strncpy(distro, buf, length);
2095 }
2096
2097 static void parse_os_info(char* distro, size_t length, const char* file) {
2098 FILE* fp = fopen(file, "r");
2099 if (fp != NULL) {
2100 // if suse format, print out first line
2101 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2102 parse_os_info_helper(fp, distro, length, get_first_line);
2103 fclose(fp);
2104 }
2105 }
2106
2107 void os::get_summary_os_info(char* buf, size_t buflen) {
2108 for (int i = 0;; i++) {
2109 const char* file = distro_files[i];
2110 if (file == NULL) {
2111 break; // ran out of distro_files
2112 }
2113 if (file_exists(file)) {
2114 parse_os_info(buf, buflen, file);
2115 return;
2116 }
2117 }
2118 // special case for debian
2119 if (file_exists("/etc/debian_version")) {
2120 strncpy(buf, "Debian ", buflen);
2121 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2122 } else {
2123 strncpy(buf, "Linux", buflen);
2124 }
2125 }
2126
2127 void os::Linux::print_libversion_info(outputStream* st) {
2128 // libc, pthread
2129 st->print("libc:");
2130 st->print("%s ", os::Linux::glibc_version());
2131 st->print("%s ", os::Linux::libpthread_version());
2132 st->cr();
2133 }
2134
2135 void os::Linux::print_full_memory_info(outputStream* st) {
2136 st->print("\n/proc/meminfo:\n");
2137 _print_ascii_file("/proc/meminfo", st);
2138 st->cr();
2139 }
2140
2141 void os::Linux::print_container_info(outputStream* st) {
2142 if (!OSContainer::is_containerized()) {
2143 return;
2144 }
2145
2146 st->print("container (cgroup) information:\n");
2147
2148 const char *p_ct = OSContainer::container_type();
2149 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed");
2150
2151 char *p = OSContainer::cpu_cpuset_cpus();
2152 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed");
2153 free(p);
2154
2155 p = OSContainer::cpu_cpuset_memory_nodes();
2156 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed");
2157 free(p);
2158
2159 int i = OSContainer::active_processor_count();
2160 if (i > 0) {
2161 st->print("active_processor_count: %d\n", i);
2162 } else {
2163 st->print("active_processor_count: failed\n");
2164 }
2165
2166 i = OSContainer::cpu_quota();
2167 st->print("cpu_quota: %d\n", i);
2168
2169 i = OSContainer::cpu_period();
2170 st->print("cpu_period: %d\n", i);
2171
2172 i = OSContainer::cpu_shares();
2173 st->print("cpu_shares: %d\n", i);
2174
2175 jlong j = OSContainer::memory_limit_in_bytes();
2176 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j);
2177
2178 j = OSContainer::memory_and_swap_limit_in_bytes();
2179 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j);
2180
2181 j = OSContainer::memory_soft_limit_in_bytes();
2182 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j);
2183
2184 j = OSContainer::OSContainer::memory_usage_in_bytes();
2185 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j);
2186
2187 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2188 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j);
2189 st->cr();
2190 }
2191
2192 void os::print_memory_info(outputStream* st) {
2193
2194 st->print("Memory:");
2195 st->print(" %dk page", os::vm_page_size()>>10);
2196
2197 // values in struct sysinfo are "unsigned long"
2198 struct sysinfo si;
2199 sysinfo(&si);
2200
2201 st->print(", physical " UINT64_FORMAT "k",
2202 os::physical_memory() >> 10);
2203 st->print("(" UINT64_FORMAT "k free)",
2204 os::available_memory() >> 10);
2205 st->print(", swap " UINT64_FORMAT "k",
2206 ((jlong)si.totalswap * si.mem_unit) >> 10);
2207 st->print("(" UINT64_FORMAT "k free)",
2208 ((jlong)si.freeswap * si.mem_unit) >> 10);
2209 st->cr();
2210 }
2211
2212 // Print the first "model name" line and the first "flags" line
2213 // that we find and nothing more. We assume "model name" comes
2214 // before "flags" so if we find a second "model name", then the
2215 // "flags" field is considered missing.
2216 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2217 #if defined(IA32) || defined(AMD64)
2218 // Other platforms have less repetitive cpuinfo files
2219 FILE *fp = fopen("/proc/cpuinfo", "r");
2220 if (fp) {
2221 while (!feof(fp)) {
2222 if (fgets(buf, buflen, fp)) {
2223 // Assume model name comes before flags
2224 bool model_name_printed = false;
2225 if (strstr(buf, "model name") != NULL) {
2226 if (!model_name_printed) {
2227 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2228 st->print_raw(buf);
2229 model_name_printed = true;
2230 } else {
2231 // model name printed but not flags? Odd, just return
2232 fclose(fp);
2233 return true;
2234 }
2235 }
2236 // print the flags line too
2237 if (strstr(buf, "flags") != NULL) {
2238 st->print_raw(buf);
2239 fclose(fp);
2240 return true;
2241 }
2242 }
2243 }
2244 fclose(fp);
2245 }
2246 #endif // x86 platforms
2247 return false;
2248 }
2249
2250 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2251 // Only print the model name if the platform provides this as a summary
2252 if (!print_model_name_and_flags(st, buf, buflen)) {
2253 st->print("\n/proc/cpuinfo:\n");
2254 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2255 st->print_cr(" <Not Available>");
2256 }
2257 }
2258 }
2259
2260 #if defined(AMD64) || defined(IA32) || defined(X32)
2261 const char* search_string = "model name";
2262 #elif defined(M68K)
2263 const char* search_string = "CPU";
2264 #elif defined(PPC64)
2265 const char* search_string = "cpu";
2266 #elif defined(S390)
2267 const char* search_string = "processor";
2268 #elif defined(SPARC)
2269 const char* search_string = "cpu";
2270 #else
2271 const char* search_string = "Processor";
2272 #endif
2273
2274 // Parses the cpuinfo file for string representing the model name.
2275 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2276 FILE* fp = fopen("/proc/cpuinfo", "r");
2277 if (fp != NULL) {
2278 while (!feof(fp)) {
2279 char buf[256];
2280 if (fgets(buf, sizeof(buf), fp)) {
2281 char* start = strstr(buf, search_string);
2282 if (start != NULL) {
2283 char *ptr = start + strlen(search_string);
2284 char *end = buf + strlen(buf);
2285 while (ptr != end) {
2286 // skip whitespace and colon for the rest of the name.
2287 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2288 break;
2289 }
2290 ptr++;
2291 }
2292 if (ptr != end) {
2293 // reasonable string, get rid of newline and keep the rest
2294 char* nl = strchr(buf, '\n');
2295 if (nl != NULL) *nl = '\0';
2296 strncpy(cpuinfo, ptr, length);
2297 fclose(fp);
2298 return;
2299 }
2300 }
2301 }
2302 }
2303 fclose(fp);
2304 }
2305 // cpuinfo not found or parsing failed, just print generic string. The entire
2306 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2307 #if defined(AARCH64)
2308 strncpy(cpuinfo, "AArch64", length);
2309 #elif defined(AMD64)
2310 strncpy(cpuinfo, "x86_64", length);
2311 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2312 strncpy(cpuinfo, "ARM", length);
2313 #elif defined(IA32)
2314 strncpy(cpuinfo, "x86_32", length);
2315 #elif defined(IA64)
2316 strncpy(cpuinfo, "IA64", length);
2317 #elif defined(PPC)
2318 strncpy(cpuinfo, "PPC64", length);
2319 #elif defined(S390)
2320 strncpy(cpuinfo, "S390", length);
2321 #elif defined(SPARC)
2322 strncpy(cpuinfo, "sparcv9", length);
2323 #elif defined(ZERO_LIBARCH)
2324 strncpy(cpuinfo, ZERO_LIBARCH, length);
2325 #else
2326 strncpy(cpuinfo, "unknown", length);
2327 #endif
2328 }
2329
2330 static void print_signal_handler(outputStream* st, int sig,
2331 char* buf, size_t buflen);
2332
2333 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2334 st->print_cr("Signal Handlers:");
2335 print_signal_handler(st, SIGSEGV, buf, buflen);
2336 print_signal_handler(st, SIGBUS , buf, buflen);
2337 print_signal_handler(st, SIGFPE , buf, buflen);
2338 print_signal_handler(st, SIGPIPE, buf, buflen);
2339 print_signal_handler(st, SIGXFSZ, buf, buflen);
2340 print_signal_handler(st, SIGILL , buf, buflen);
2341 print_signal_handler(st, SR_signum, buf, buflen);
2342 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2343 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2344 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2345 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2346 #if defined(PPC64)
2347 print_signal_handler(st, SIGTRAP, buf, buflen);
2348 #endif
2349 }
2350
2351 static char saved_jvm_path[MAXPATHLEN] = {0};
2352
2353 // Find the full path to the current module, libjvm.so
2354 void os::jvm_path(char *buf, jint buflen) {
2355 // Error checking.
2356 if (buflen < MAXPATHLEN) {
2357 assert(false, "must use a large-enough buffer");
2358 buf[0] = '\0';
2359 return;
2360 }
2361 // Lazy resolve the path to current module.
2362 if (saved_jvm_path[0] != 0) {
2363 strcpy(buf, saved_jvm_path);
2364 return;
2365 }
2366
2367 char dli_fname[MAXPATHLEN];
2368 bool ret = dll_address_to_library_name(
2369 CAST_FROM_FN_PTR(address, os::jvm_path),
2370 dli_fname, sizeof(dli_fname), NULL);
2371 assert(ret, "cannot locate libjvm");
2372 char *rp = NULL;
2373 if (ret && dli_fname[0] != '\0') {
2374 rp = os::Posix::realpath(dli_fname, buf, buflen);
2375 }
2376 if (rp == NULL) {
2377 return;
2378 }
2379
2380 if (Arguments::sun_java_launcher_is_altjvm()) {
2381 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2382 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2383 // If "/jre/lib/" appears at the right place in the string, then
2384 // assume we are installed in a JDK and we're done. Otherwise, check
2385 // for a JAVA_HOME environment variable and fix up the path so it
2386 // looks like libjvm.so is installed there (append a fake suffix
2387 // hotspot/libjvm.so).
2388 const char *p = buf + strlen(buf) - 1;
2389 for (int count = 0; p > buf && count < 5; ++count) {
2390 for (--p; p > buf && *p != '/'; --p)
2391 /* empty */ ;
2392 }
2393
2394 if (strncmp(p, "/jre/lib/", 9) != 0) {
2395 // Look for JAVA_HOME in the environment.
2396 char* java_home_var = ::getenv("JAVA_HOME");
2397 if (java_home_var != NULL && java_home_var[0] != 0) {
2398 char* jrelib_p;
2399 int len;
2400
2401 // Check the current module name "libjvm.so".
2402 p = strrchr(buf, '/');
2403 if (p == NULL) {
2404 return;
2405 }
2406 assert(strstr(p, "/libjvm") == p, "invalid library name");
2407
2408 rp = os::Posix::realpath(java_home_var, buf, buflen);
2409 if (rp == NULL) {
2410 return;
2411 }
2412
2413 // determine if this is a legacy image or modules image
2414 // modules image doesn't have "jre" subdirectory
2415 len = strlen(buf);
2416 assert(len < buflen, "Ran out of buffer room");
2417 jrelib_p = buf + len;
2418 snprintf(jrelib_p, buflen-len, "/jre/lib");
2419 if (0 != access(buf, F_OK)) {
2420 snprintf(jrelib_p, buflen-len, "/lib");
2421 }
2422
2423 if (0 == access(buf, F_OK)) {
2424 // Use current module name "libjvm.so"
2425 len = strlen(buf);
2426 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2427 } else {
2428 // Go back to path of .so
2429 rp = os::Posix::realpath(dli_fname, buf, buflen);
2430 if (rp == NULL) {
2431 return;
2432 }
2433 }
2434 }
2435 }
2436 }
2437
2438 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2439 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2440 }
2441
2442 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2443 // no prefix required, not even "_"
2444 }
2445
2446 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2447 // no suffix required
2448 }
2449
2450 ////////////////////////////////////////////////////////////////////////////////
2451 // sun.misc.Signal support
2452
2453 static volatile jint sigint_count = 0;
2454
2455 static void UserHandler(int sig, void *siginfo, void *context) {
2456 // 4511530 - sem_post is serialized and handled by the manager thread. When
2457 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2458 // don't want to flood the manager thread with sem_post requests.
2459 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2460 return;
2461 }
2462
2463 // Ctrl-C is pressed during error reporting, likely because the error
2464 // handler fails to abort. Let VM die immediately.
2465 if (sig == SIGINT && VMError::is_error_reported()) {
2466 os::die();
2467 }
2468
2469 os::signal_notify(sig);
2470 }
2471
2472 void* os::user_handler() {
2473 return CAST_FROM_FN_PTR(void*, UserHandler);
2474 }
2475
2476 static struct timespec create_semaphore_timespec(unsigned int sec, int nsec) {
2477 struct timespec ts;
2478 // Semaphore's are always associated with CLOCK_REALTIME
2479 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2480 // see os_posix.cpp for discussion on overflow checking
2481 if (sec >= MAX_SECS) {
2482 ts.tv_sec += MAX_SECS;
2483 ts.tv_nsec = 0;
2484 } else {
2485 ts.tv_sec += sec;
2486 ts.tv_nsec += nsec;
2487 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2488 ts.tv_nsec -= NANOSECS_PER_SEC;
2489 ++ts.tv_sec; // note: this must be <= max_secs
2490 }
2491 }
2492
2493 return ts;
2494 }
2495
2496 extern "C" {
2497 typedef void (*sa_handler_t)(int);
2498 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2499 }
2500
2501 void* os::signal(int signal_number, void* handler) {
2502 struct sigaction sigAct, oldSigAct;
2503
2504 sigfillset(&(sigAct.sa_mask));
2505 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2506 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2507
2508 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2509 // -1 means registration failed
2510 return (void *)-1;
2511 }
2512
2513 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2514 }
2515
2516 void os::signal_raise(int signal_number) {
2517 ::raise(signal_number);
2518 }
2519
2520 // The following code is moved from os.cpp for making this
2521 // code platform specific, which it is by its very nature.
2522
2523 // Will be modified when max signal is changed to be dynamic
2524 int os::sigexitnum_pd() {
2525 return NSIG;
2526 }
2527
2528 // a counter for each possible signal value
2529 static volatile jint pending_signals[NSIG+1] = { 0 };
2530
2531 // Linux(POSIX) specific hand shaking semaphore.
2532 static Semaphore* sig_sem = NULL;
2533 static PosixSemaphore sr_semaphore;
2534
2535 void os::signal_init_pd() {
2536 // Initialize signal structures
2537 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2538
2539 // Initialize signal semaphore
2540 sig_sem = new Semaphore();
2541 }
2542
2543 void os::signal_notify(int sig) {
2544 if (sig_sem != NULL) {
2545 Atomic::inc(&pending_signals[sig]);
2546 sig_sem->signal();
2547 } else {
2548 // Signal thread is not created with ReduceSignalUsage and signal_init_pd
2549 // initialization isn't called.
2550 assert(ReduceSignalUsage, "signal semaphore should be created");
2551 }
2552 }
2553
2554 static int check_pending_signals() {
2555 Atomic::store(0, &sigint_count);
2556 for (;;) {
2557 for (int i = 0; i < NSIG + 1; i++) {
2558 jint n = pending_signals[i];
2559 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2560 return i;
2561 }
2562 }
2563 JavaThread *thread = JavaThread::current();
2564 ThreadBlockInVM tbivm(thread);
2565
2566 bool threadIsSuspended;
2567 do {
2568 thread->set_suspend_equivalent();
2569 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2570 sig_sem->wait();
2571
2572 // were we externally suspended while we were waiting?
2573 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2574 if (threadIsSuspended) {
2575 // The semaphore has been incremented, but while we were waiting
2576 // another thread suspended us. We don't want to continue running
2577 // while suspended because that would surprise the thread that
2578 // suspended us.
2579 sig_sem->signal();
2580
2581 thread->java_suspend_self();
2582 }
2583 } while (threadIsSuspended);
2584 }
2585 }
2586
2587 int os::signal_wait() {
2588 return check_pending_signals();
2589 }
2590
2591 ////////////////////////////////////////////////////////////////////////////////
2592 // Virtual Memory
2593
2594 int os::vm_page_size() {
2595 // Seems redundant as all get out
2596 assert(os::Linux::page_size() != -1, "must call os::init");
2597 return os::Linux::page_size();
2598 }
2599
2600 // Solaris allocates memory by pages.
2601 int os::vm_allocation_granularity() {
2602 assert(os::Linux::page_size() != -1, "must call os::init");
2603 return os::Linux::page_size();
2604 }
2605
2606 // Rationale behind this function:
2607 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2608 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2609 // samples for JITted code. Here we create private executable mapping over the code cache
2610 // and then we can use standard (well, almost, as mapping can change) way to provide
2611 // info for the reporting script by storing timestamp and location of symbol
2612 void linux_wrap_code(char* base, size_t size) {
2613 static volatile jint cnt = 0;
2614
2615 if (!UseOprofile) {
2616 return;
2617 }
2618
2619 char buf[PATH_MAX+1];
2620 int num = Atomic::add(1, &cnt);
2621
2622 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2623 os::get_temp_directory(), os::current_process_id(), num);
2624 unlink(buf);
2625
2626 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2627
2628 if (fd != -1) {
2629 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2630 if (rv != (off_t)-1) {
2631 if (::write(fd, "", 1) == 1) {
2632 mmap(base, size,
2633 PROT_READ|PROT_WRITE|PROT_EXEC,
2634 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2635 }
2636 }
2637 ::close(fd);
2638 unlink(buf);
2639 }
2640 }
2641
2642 static bool recoverable_mmap_error(int err) {
2643 // See if the error is one we can let the caller handle. This
2644 // list of errno values comes from JBS-6843484. I can't find a
2645 // Linux man page that documents this specific set of errno
2646 // values so while this list currently matches Solaris, it may
2647 // change as we gain experience with this failure mode.
2648 switch (err) {
2649 case EBADF:
2650 case EINVAL:
2651 case ENOTSUP:
2652 // let the caller deal with these errors
2653 return true;
2654
2655 default:
2656 // Any remaining errors on this OS can cause our reserved mapping
2657 // to be lost. That can cause confusion where different data
2658 // structures think they have the same memory mapped. The worst
2659 // scenario is if both the VM and a library think they have the
2660 // same memory mapped.
2661 return false;
2662 }
2663 }
2664
2665 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2666 int err) {
2667 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2668 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2669 os::strerror(err), err);
2670 }
2671
2672 static void warn_fail_commit_memory(char* addr, size_t size,
2673 size_t alignment_hint, bool exec,
2674 int err) {
2675 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2676 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2677 alignment_hint, exec, os::strerror(err), err);
2678 }
2679
2680 // NOTE: Linux kernel does not really reserve the pages for us.
2681 // All it does is to check if there are enough free pages
2682 // left at the time of mmap(). This could be a potential
2683 // problem.
2684 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2685 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2686 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2687 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2688 if (res != (uintptr_t) MAP_FAILED) {
2689 if (UseNUMAInterleaving) {
2690 numa_make_global(addr, size);
2691 }
2692 return 0;
2693 }
2694
2695 int err = errno; // save errno from mmap() call above
2696
2697 if (!recoverable_mmap_error(err)) {
2698 warn_fail_commit_memory(addr, size, exec, err);
2699 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2700 }
2701
2702 return err;
2703 }
2704
2705 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2706 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2707 }
2708
2709 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2710 const char* mesg) {
2711 assert(mesg != NULL, "mesg must be specified");
2712 int err = os::Linux::commit_memory_impl(addr, size, exec);
2713 if (err != 0) {
2714 // the caller wants all commit errors to exit with the specified mesg:
2715 warn_fail_commit_memory(addr, size, exec, err);
2716 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2717 }
2718 }
2719
2720 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2721 #ifndef MAP_HUGETLB
2722 #define MAP_HUGETLB 0x40000
2723 #endif
2724
2725 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2726 #ifndef MADV_HUGEPAGE
2727 #define MADV_HUGEPAGE 14
2728 #endif
2729
2730 int os::Linux::commit_memory_impl(char* addr, size_t size,
2731 size_t alignment_hint, bool exec) {
2732 int err = os::Linux::commit_memory_impl(addr, size, exec);
2733 if (err == 0) {
2734 realign_memory(addr, size, alignment_hint);
2735 }
2736 return err;
2737 }
2738
2739 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2740 bool exec) {
2741 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2742 }
2743
2744 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2745 size_t alignment_hint, bool exec,
2746 const char* mesg) {
2747 assert(mesg != NULL, "mesg must be specified");
2748 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2749 if (err != 0) {
2750 // the caller wants all commit errors to exit with the specified mesg:
2751 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2752 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2753 }
2754 }
2755
2756 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2757 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2758 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2759 // be supported or the memory may already be backed by huge pages.
2760 ::madvise(addr, bytes, MADV_HUGEPAGE);
2761 }
2762 }
2763
2764 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2765 // This method works by doing an mmap over an existing mmaping and effectively discarding
2766 // the existing pages. However it won't work for SHM-based large pages that cannot be
2767 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2768 // small pages on top of the SHM segment. This method always works for small pages, so we
2769 // allow that in any case.
2770 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2771 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2772 }
2773 }
2774
2775 void os::numa_make_global(char *addr, size_t bytes) {
2776 Linux::numa_interleave_memory(addr, bytes);
2777 }
2778
2779 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2780 // bind policy to MPOL_PREFERRED for the current thread.
2781 #define USE_MPOL_PREFERRED 0
2782
2783 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2784 // To make NUMA and large pages more robust when both enabled, we need to ease
2785 // the requirements on where the memory should be allocated. MPOL_BIND is the
2786 // default policy and it will force memory to be allocated on the specified
2787 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2788 // the specified node, but will not force it. Using this policy will prevent
2789 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2790 // free large pages.
2791 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2792 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2793 }
2794
2795 bool os::numa_topology_changed() { return false; }
2796
2797 size_t os::numa_get_groups_num() {
2798 // Return just the number of nodes in which it's possible to allocate memory
2799 // (in numa terminology, configured nodes).
2800 return Linux::numa_num_configured_nodes();
2801 }
2802
2803 int os::numa_get_group_id() {
2804 int cpu_id = Linux::sched_getcpu();
2805 if (cpu_id != -1) {
2806 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2807 if (lgrp_id != -1) {
2808 return lgrp_id;
2809 }
2810 }
2811 return 0;
2812 }
2813
2814 int os::Linux::get_existing_num_nodes() {
2815 size_t node;
2816 size_t highest_node_number = Linux::numa_max_node();
2817 int num_nodes = 0;
2818
2819 // Get the total number of nodes in the system including nodes without memory.
2820 for (node = 0; node <= highest_node_number; node++) {
2821 if (isnode_in_existing_nodes(node)) {
2822 num_nodes++;
2823 }
2824 }
2825 return num_nodes;
2826 }
2827
2828 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2829 size_t highest_node_number = Linux::numa_max_node();
2830 size_t i = 0;
2831
2832 // Map all node ids in which is possible to allocate memory. Also nodes are
2833 // not always consecutively available, i.e. available from 0 to the highest
2834 // node number.
2835 for (size_t node = 0; node <= highest_node_number; node++) {
2836 if (Linux::isnode_in_configured_nodes(node)) {
2837 ids[i++] = node;
2838 }
2839 }
2840 return i;
2841 }
2842
2843 bool os::get_page_info(char *start, page_info* info) {
2844 return false;
2845 }
2846
2847 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2848 page_info* page_found) {
2849 return end;
2850 }
2851
2852
2853 int os::Linux::sched_getcpu_syscall(void) {
2854 unsigned int cpu = 0;
2855 int retval = -1;
2856
2857 #if defined(IA32)
2858 #ifndef SYS_getcpu
2859 #define SYS_getcpu 318
2860 #endif
2861 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2862 #elif defined(AMD64)
2863 // Unfortunately we have to bring all these macros here from vsyscall.h
2864 // to be able to compile on old linuxes.
2865 #define __NR_vgetcpu 2
2866 #define VSYSCALL_START (-10UL << 20)
2867 #define VSYSCALL_SIZE 1024
2868 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2869 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2870 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2871 retval = vgetcpu(&cpu, NULL, NULL);
2872 #endif
2873
2874 return (retval == -1) ? retval : cpu;
2875 }
2876
2877 void os::Linux::sched_getcpu_init() {
2878 // sched_getcpu() should be in libc.
2879 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2880 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2881
2882 // If it's not, try a direct syscall.
2883 if (sched_getcpu() == -1) {
2884 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2885 (void*)&sched_getcpu_syscall));
2886 }
2887 }
2888
2889 // Something to do with the numa-aware allocator needs these symbols
2890 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2891 extern "C" JNIEXPORT void numa_error(char *where) { }
2892
2893 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
2894 // load symbol from base version instead.
2895 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2896 void *f = dlvsym(handle, name, "libnuma_1.1");
2897 if (f == NULL) {
2898 f = dlsym(handle, name);
2899 }
2900 return f;
2901 }
2902
2903 // Handle request to load libnuma symbol version 1.2 (API v2) only.
2904 // Return NULL if the symbol is not defined in this particular version.
2905 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
2906 return dlvsym(handle, name, "libnuma_1.2");
2907 }
2908
2909 bool os::Linux::libnuma_init() {
2910 if (sched_getcpu() != -1) { // Requires sched_getcpu() support
2911 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2912 if (handle != NULL) {
2913 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2914 libnuma_dlsym(handle, "numa_node_to_cpus")));
2915 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2916 libnuma_dlsym(handle, "numa_max_node")));
2917 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
2918 libnuma_dlsym(handle, "numa_num_configured_nodes")));
2919 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2920 libnuma_dlsym(handle, "numa_available")));
2921 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2922 libnuma_dlsym(handle, "numa_tonode_memory")));
2923 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2924 libnuma_dlsym(handle, "numa_interleave_memory")));
2925 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
2926 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
2927 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2928 libnuma_dlsym(handle, "numa_set_bind_policy")));
2929 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
2930 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
2931 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
2932 libnuma_dlsym(handle, "numa_distance")));
2933
2934 if (numa_available() != -1) {
2935 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2936 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
2937 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
2938 // Create an index -> node mapping, since nodes are not always consecutive
2939 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2940 rebuild_nindex_to_node_map();
2941 // Create a cpu -> node mapping
2942 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2943 rebuild_cpu_to_node_map();
2944 return true;
2945 }
2946 }
2947 }
2948 return false;
2949 }
2950
2951 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
2952 // Creating guard page is very expensive. Java thread has HotSpot
2953 // guard pages, only enable glibc guard page for non-Java threads.
2954 // (Remember: compiler thread is a Java thread, too!)
2955 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
2956 }
2957
2958 void os::Linux::rebuild_nindex_to_node_map() {
2959 int highest_node_number = Linux::numa_max_node();
2960
2961 nindex_to_node()->clear();
2962 for (int node = 0; node <= highest_node_number; node++) {
2963 if (Linux::isnode_in_existing_nodes(node)) {
2964 nindex_to_node()->append(node);
2965 }
2966 }
2967 }
2968
2969 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2970 // The table is later used in get_node_by_cpu().
2971 void os::Linux::rebuild_cpu_to_node_map() {
2972 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2973 // in libnuma (possible values are starting from 16,
2974 // and continuing up with every other power of 2, but less
2975 // than the maximum number of CPUs supported by kernel), and
2976 // is a subject to change (in libnuma version 2 the requirements
2977 // are more reasonable) we'll just hardcode the number they use
2978 // in the library.
2979 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2980
2981 size_t cpu_num = processor_count();
2982 size_t cpu_map_size = NCPUS / BitsPerCLong;
2983 size_t cpu_map_valid_size =
2984 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2985
2986 cpu_to_node()->clear();
2987 cpu_to_node()->at_grow(cpu_num - 1);
2988
2989 size_t node_num = get_existing_num_nodes();
2990
2991 int distance = 0;
2992 int closest_distance = INT_MAX;
2993 int closest_node = 0;
2994 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2995 for (size_t i = 0; i < node_num; i++) {
2996 // Check if node is configured (not a memory-less node). If it is not, find
2997 // the closest configured node.
2998 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) {
2999 closest_distance = INT_MAX;
3000 // Check distance from all remaining nodes in the system. Ignore distance
3001 // from itself and from another non-configured node.
3002 for (size_t m = 0; m < node_num; m++) {
3003 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) {
3004 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3005 // If a closest node is found, update. There is always at least one
3006 // configured node in the system so there is always at least one node
3007 // close.
3008 if (distance != 0 && distance < closest_distance) {
3009 closest_distance = distance;
3010 closest_node = nindex_to_node()->at(m);
3011 }
3012 }
3013 }
3014 } else {
3015 // Current node is already a configured node.
3016 closest_node = nindex_to_node()->at(i);
3017 }
3018
3019 // Get cpus from the original node and map them to the closest node. If node
3020 // is a configured node (not a memory-less node), then original node and
3021 // closest node are the same.
3022 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3023 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3024 if (cpu_map[j] != 0) {
3025 for (size_t k = 0; k < BitsPerCLong; k++) {
3026 if (cpu_map[j] & (1UL << k)) {
3027 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3028 }
3029 }
3030 }
3031 }
3032 }
3033 }
3034 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
3035 }
3036
3037 int os::Linux::get_node_by_cpu(int cpu_id) {
3038 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3039 return cpu_to_node()->at(cpu_id);
3040 }
3041 return -1;
3042 }
3043
3044 GrowableArray<int>* os::Linux::_cpu_to_node;
3045 GrowableArray<int>* os::Linux::_nindex_to_node;
3046 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3047 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3048 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3049 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3050 os::Linux::numa_available_func_t os::Linux::_numa_available;
3051 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3052 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3053 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3054 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3055 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3056 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3057 unsigned long* os::Linux::_numa_all_nodes;
3058 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3059 struct bitmask* os::Linux::_numa_nodes_ptr;
3060
3061 bool os::pd_uncommit_memory(char* addr, size_t size) {
3062 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3063 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3064 return res != (uintptr_t) MAP_FAILED;
3065 }
3066
3067 static address get_stack_commited_bottom(address bottom, size_t size) {
3068 address nbot = bottom;
3069 address ntop = bottom + size;
3070
3071 size_t page_sz = os::vm_page_size();
3072 unsigned pages = size / page_sz;
3073
3074 unsigned char vec[1];
3075 unsigned imin = 1, imax = pages + 1, imid;
3076 int mincore_return_value = 0;
3077
3078 assert(imin <= imax, "Unexpected page size");
3079
3080 while (imin < imax) {
3081 imid = (imax + imin) / 2;
3082 nbot = ntop - (imid * page_sz);
3083
3084 // Use a trick with mincore to check whether the page is mapped or not.
3085 // mincore sets vec to 1 if page resides in memory and to 0 if page
3086 // is swapped output but if page we are asking for is unmapped
3087 // it returns -1,ENOMEM
3088 mincore_return_value = mincore(nbot, page_sz, vec);
3089
3090 if (mincore_return_value == -1) {
3091 // Page is not mapped go up
3092 // to find first mapped page
3093 if (errno != EAGAIN) {
3094 assert(errno == ENOMEM, "Unexpected mincore errno");
3095 imax = imid;
3096 }
3097 } else {
3098 // Page is mapped go down
3099 // to find first not mapped page
3100 imin = imid + 1;
3101 }
3102 }
3103
3104 nbot = nbot + page_sz;
3105
3106 // Adjust stack bottom one page up if last checked page is not mapped
3107 if (mincore_return_value == -1) {
3108 nbot = nbot + page_sz;
3109 }
3110
3111 return nbot;
3112 }
3113
3114 bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
3115 int mincore_return_value;
3116 const size_t stripe = 1024; // query this many pages each time
3117 unsigned char vec[stripe];
3118 const size_t page_sz = os::vm_page_size();
3119 size_t pages = size / page_sz;
3120
3121 assert(is_aligned(start, page_sz), "Start address must be page aligned");
3122 assert(is_aligned(size, page_sz), "Size must be page aligned");
3123
3124 committed_start = NULL;
3125
3126 int loops = (pages + stripe - 1) / stripe;
3127 int committed_pages = 0;
3128 address loop_base = start;
3129 for (int index = 0; index < loops; index ++) {
3130 assert(pages > 0, "Nothing to do");
3131 int pages_to_query = (pages >= stripe) ? stripe : pages;
3132 pages -= pages_to_query;
3133
3134 // Get stable read
3135 while ((mincore_return_value = mincore(loop_base, pages_to_query * page_sz, vec)) == -1 && errno == EAGAIN);
3136
3137 // During shutdown, some memory goes away without properly notifying NMT,
3138 // E.g. ConcurrentGCThread/WatcherThread can exit without deleting thread object.
3139 // Bailout and return as not committed for now.
3140 if (mincore_return_value == -1 && errno == ENOMEM) {
3141 return false;
3142 }
3143
3144 assert(mincore_return_value == 0, "Range must be valid");
3145 // Process this stripe
3146 for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
3147 if ((vec[vecIdx] & 0x01) == 0) { // not committed
3148 // End of current contiguous region
3149 if (committed_start != NULL) {
3150 break;
3151 }
3152 } else { // committed
3153 // Start of region
3154 if (committed_start == NULL) {
3155 committed_start = loop_base + page_sz * vecIdx;
3156 }
3157 committed_pages ++;
3158 }
3159 }
3160
3161 loop_base += pages_to_query * page_sz;
3162 }
3163
3164 if (committed_start != NULL) {
3165 assert(committed_pages > 0, "Must have committed region");
3166 assert(committed_pages <= int(size / page_sz), "Can not commit more than it has");
3167 assert(committed_start >= start && committed_start < start + size, "Out of range");
3168 committed_size = page_sz * committed_pages;
3169 return true;
3170 } else {
3171 assert(committed_pages == 0, "Should not have committed region");
3172 return false;
3173 }
3174 }
3175
3176
3177 // Linux uses a growable mapping for the stack, and if the mapping for
3178 // the stack guard pages is not removed when we detach a thread the
3179 // stack cannot grow beyond the pages where the stack guard was
3180 // mapped. If at some point later in the process the stack expands to
3181 // that point, the Linux kernel cannot expand the stack any further
3182 // because the guard pages are in the way, and a segfault occurs.
3183 //
3184 // However, it's essential not to split the stack region by unmapping
3185 // a region (leaving a hole) that's already part of the stack mapping,
3186 // so if the stack mapping has already grown beyond the guard pages at
3187 // the time we create them, we have to truncate the stack mapping.
3188 // So, we need to know the extent of the stack mapping when
3189 // create_stack_guard_pages() is called.
3190
3191 // We only need this for stacks that are growable: at the time of
3192 // writing thread stacks don't use growable mappings (i.e. those
3193 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3194 // only applies to the main thread.
3195
3196 // If the (growable) stack mapping already extends beyond the point
3197 // where we're going to put our guard pages, truncate the mapping at
3198 // that point by munmap()ping it. This ensures that when we later
3199 // munmap() the guard pages we don't leave a hole in the stack
3200 // mapping. This only affects the main/primordial thread
3201
3202 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3203 if (os::is_primordial_thread()) {
3204 // As we manually grow stack up to bottom inside create_attached_thread(),
3205 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3206 // we don't need to do anything special.
3207 // Check it first, before calling heavy function.
3208 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3209 unsigned char vec[1];
3210
3211 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3212 // Fallback to slow path on all errors, including EAGAIN
3213 stack_extent = (uintptr_t) get_stack_commited_bottom(
3214 os::Linux::initial_thread_stack_bottom(),
3215 (size_t)addr - stack_extent);
3216 }
3217
3218 if (stack_extent < (uintptr_t)addr) {
3219 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3220 }
3221 }
3222
3223 return os::commit_memory(addr, size, !ExecMem);
3224 }
3225
3226 // If this is a growable mapping, remove the guard pages entirely by
3227 // munmap()ping them. If not, just call uncommit_memory(). This only
3228 // affects the main/primordial thread, but guard against future OS changes.
3229 // It's safe to always unmap guard pages for primordial thread because we
3230 // always place it right after end of the mapped region.
3231
3232 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3233 uintptr_t stack_extent, stack_base;
3234
3235 if (os::is_primordial_thread()) {
3236 return ::munmap(addr, size) == 0;
3237 }
3238
3239 return os::uncommit_memory(addr, size);
3240 }
3241
3242 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3243 // at 'requested_addr'. If there are existing memory mappings at the same
3244 // location, however, they will be overwritten. If 'fixed' is false,
3245 // 'requested_addr' is only treated as a hint, the return value may or
3246 // may not start from the requested address. Unlike Linux mmap(), this
3247 // function returns NULL to indicate failure.
3248 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3249 char * addr;
3250 int flags;
3251
3252 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3253 if (fixed) {
3254 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3255 flags |= MAP_FIXED;
3256 }
3257
3258 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3259 // touch an uncommitted page. Otherwise, the read/write might
3260 // succeed if we have enough swap space to back the physical page.
3261 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3262 flags, -1, 0);
3263
3264 return addr == MAP_FAILED ? NULL : addr;
3265 }
3266
3267 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3268 // (req_addr != NULL) or with a given alignment.
3269 // - bytes shall be a multiple of alignment.
3270 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3271 // - alignment sets the alignment at which memory shall be allocated.
3272 // It must be a multiple of allocation granularity.
3273 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3274 // req_addr or NULL.
3275 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3276
3277 size_t extra_size = bytes;
3278 if (req_addr == NULL && alignment > 0) {
3279 extra_size += alignment;
3280 }
3281
3282 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3283 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3284 -1, 0);
3285 if (start == MAP_FAILED) {
3286 start = NULL;
3287 } else {
3288 if (req_addr != NULL) {
3289 if (start != req_addr) {
3290 ::munmap(start, extra_size);
3291 start = NULL;
3292 }
3293 } else {
3294 char* const start_aligned = align_up(start, alignment);
3295 char* const end_aligned = start_aligned + bytes;
3296 char* const end = start + extra_size;
3297 if (start_aligned > start) {
3298 ::munmap(start, start_aligned - start);
3299 }
3300 if (end_aligned < end) {
3301 ::munmap(end_aligned, end - end_aligned);
3302 }
3303 start = start_aligned;
3304 }
3305 }
3306 return start;
3307 }
3308
3309 static int anon_munmap(char * addr, size_t size) {
3310 return ::munmap(addr, size) == 0;
3311 }
3312
3313 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3314 size_t alignment_hint) {
3315 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3316 }
3317
3318 bool os::pd_release_memory(char* addr, size_t size) {
3319 return anon_munmap(addr, size);
3320 }
3321
3322 static bool linux_mprotect(char* addr, size_t size, int prot) {
3323 // Linux wants the mprotect address argument to be page aligned.
3324 char* bottom = (char*)align_down((intptr_t)addr, os::Linux::page_size());
3325
3326 // According to SUSv3, mprotect() should only be used with mappings
3327 // established by mmap(), and mmap() always maps whole pages. Unaligned
3328 // 'addr' likely indicates problem in the VM (e.g. trying to change
3329 // protection of malloc'ed or statically allocated memory). Check the
3330 // caller if you hit this assert.
3331 assert(addr == bottom, "sanity check");
3332
3333 size = align_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3334 return ::mprotect(bottom, size, prot) == 0;
3335 }
3336
3337 // Set protections specified
3338 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3339 bool is_committed) {
3340 unsigned int p = 0;
3341 switch (prot) {
3342 case MEM_PROT_NONE: p = PROT_NONE; break;
3343 case MEM_PROT_READ: p = PROT_READ; break;
3344 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3345 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3346 default:
3347 ShouldNotReachHere();
3348 }
3349 // is_committed is unused.
3350 return linux_mprotect(addr, bytes, p);
3351 }
3352
3353 bool os::guard_memory(char* addr, size_t size) {
3354 return linux_mprotect(addr, size, PROT_NONE);
3355 }
3356
3357 bool os::unguard_memory(char* addr, size_t size) {
3358 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3359 }
3360
3361 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3362 size_t page_size) {
3363 bool result = false;
3364 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3365 MAP_ANONYMOUS|MAP_PRIVATE,
3366 -1, 0);
3367 if (p != MAP_FAILED) {
3368 void *aligned_p = align_up(p, page_size);
3369
3370 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3371
3372 munmap(p, page_size * 2);
3373 }
3374
3375 if (warn && !result) {
3376 warning("TransparentHugePages is not supported by the operating system.");
3377 }
3378
3379 return result;
3380 }
3381
3382 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3383 bool result = false;
3384 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3385 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3386 -1, 0);
3387
3388 if (p != MAP_FAILED) {
3389 // We don't know if this really is a huge page or not.
3390 FILE *fp = fopen("/proc/self/maps", "r");
3391 if (fp) {
3392 while (!feof(fp)) {
3393 char chars[257];
3394 long x = 0;
3395 if (fgets(chars, sizeof(chars), fp)) {
3396 if (sscanf(chars, "%lx-%*x", &x) == 1
3397 && x == (long)p) {
3398 if (strstr (chars, "hugepage")) {
3399 result = true;
3400 break;
3401 }
3402 }
3403 }
3404 }
3405 fclose(fp);
3406 }
3407 munmap(p, page_size);
3408 }
3409
3410 if (warn && !result) {
3411 warning("HugeTLBFS is not supported by the operating system.");
3412 }
3413
3414 return result;
3415 }
3416
3417 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3418 //
3419 // From the coredump_filter documentation:
3420 //
3421 // - (bit 0) anonymous private memory
3422 // - (bit 1) anonymous shared memory
3423 // - (bit 2) file-backed private memory
3424 // - (bit 3) file-backed shared memory
3425 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3426 // effective only if the bit 2 is cleared)
3427 // - (bit 5) hugetlb private memory
3428 // - (bit 6) hugetlb shared memory
3429 // - (bit 7) dax private memory
3430 // - (bit 8) dax shared memory
3431 //
3432 static void set_coredump_filter(bool largepages, bool dax_shared) {
3433 FILE *f;
3434 long cdm;
3435 bool filter_changed = false;
3436
3437 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3438 return;
3439 }
3440
3441 if (fscanf(f, "%lx", &cdm) != 1) {
3442 fclose(f);
3443 return;
3444 }
3445
3446 rewind(f);
3447
3448 if (largepages && (cdm & LARGEPAGES_BIT) == 0) {
3449 cdm |= LARGEPAGES_BIT;
3450 filter_changed = true;
3451 }
3452 if (dax_shared && (cdm & DAX_SHARED_BIT) == 0) {
3453 cdm |= DAX_SHARED_BIT;
3454 filter_changed = true;
3455 }
3456 if (filter_changed) {
3457 fprintf(f, "%#lx", cdm);
3458 }
3459
3460 fclose(f);
3461 }
3462
3463 // Large page support
3464
3465 static size_t _large_page_size = 0;
3466
3467 size_t os::Linux::find_large_page_size() {
3468 size_t large_page_size = 0;
3469
3470 // large_page_size on Linux is used to round up heap size. x86 uses either
3471 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3472 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3473 // page as large as 256M.
3474 //
3475 // Here we try to figure out page size by parsing /proc/meminfo and looking
3476 // for a line with the following format:
3477 // Hugepagesize: 2048 kB
3478 //
3479 // If we can't determine the value (e.g. /proc is not mounted, or the text
3480 // format has been changed), we'll use the largest page size supported by
3481 // the processor.
3482
3483 #ifndef ZERO
3484 large_page_size =
3485 AARCH64_ONLY(2 * M)
3486 AMD64_ONLY(2 * M)
3487 ARM32_ONLY(2 * M)
3488 IA32_ONLY(4 * M)
3489 IA64_ONLY(256 * M)
3490 PPC_ONLY(4 * M)
3491 S390_ONLY(1 * M)
3492 SPARC_ONLY(4 * M);
3493 #endif // ZERO
3494
3495 FILE *fp = fopen("/proc/meminfo", "r");
3496 if (fp) {
3497 while (!feof(fp)) {
3498 int x = 0;
3499 char buf[16];
3500 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3501 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3502 large_page_size = x * K;
3503 break;
3504 }
3505 } else {
3506 // skip to next line
3507 for (;;) {
3508 int ch = fgetc(fp);
3509 if (ch == EOF || ch == (int)'\n') break;
3510 }
3511 }
3512 }
3513 fclose(fp);
3514 }
3515
3516 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3517 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3518 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3519 proper_unit_for_byte_size(large_page_size));
3520 }
3521
3522 return large_page_size;
3523 }
3524
3525 size_t os::Linux::setup_large_page_size() {
3526 _large_page_size = Linux::find_large_page_size();
3527 const size_t default_page_size = (size_t)Linux::page_size();
3528 if (_large_page_size > default_page_size) {
3529 _page_sizes[0] = _large_page_size;
3530 _page_sizes[1] = default_page_size;
3531 _page_sizes[2] = 0;
3532 }
3533
3534 return _large_page_size;
3535 }
3536
3537 bool os::Linux::setup_large_page_type(size_t page_size) {
3538 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3539 FLAG_IS_DEFAULT(UseSHM) &&
3540 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3541
3542 // The type of large pages has not been specified by the user.
3543
3544 // Try UseHugeTLBFS and then UseSHM.
3545 UseHugeTLBFS = UseSHM = true;
3546
3547 // Don't try UseTransparentHugePages since there are known
3548 // performance issues with it turned on. This might change in the future.
3549 UseTransparentHugePages = false;
3550 }
3551
3552 if (UseTransparentHugePages) {
3553 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3554 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3555 UseHugeTLBFS = false;
3556 UseSHM = false;
3557 return true;
3558 }
3559 UseTransparentHugePages = false;
3560 }
3561
3562 if (UseHugeTLBFS) {
3563 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3564 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3565 UseSHM = false;
3566 return true;
3567 }
3568 UseHugeTLBFS = false;
3569 }
3570
3571 return UseSHM;
3572 }
3573
3574 void os::large_page_init() {
3575 if (!UseLargePages &&
3576 !UseTransparentHugePages &&
3577 !UseHugeTLBFS &&
3578 !UseSHM) {
3579 // Not using large pages.
3580 return;
3581 }
3582
3583 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3584 // The user explicitly turned off large pages.
3585 // Ignore the rest of the large pages flags.
3586 UseTransparentHugePages = false;
3587 UseHugeTLBFS = false;
3588 UseSHM = false;
3589 return;
3590 }
3591
3592 size_t large_page_size = Linux::setup_large_page_size();
3593 UseLargePages = Linux::setup_large_page_type(large_page_size);
3594
3595 set_coredump_filter(true /*largepages*/, false /*dax_shared*/);
3596 }
3597
3598 #ifndef SHM_HUGETLB
3599 #define SHM_HUGETLB 04000
3600 #endif
3601
3602 #define shm_warning_format(format, ...) \
3603 do { \
3604 if (UseLargePages && \
3605 (!FLAG_IS_DEFAULT(UseLargePages) || \
3606 !FLAG_IS_DEFAULT(UseSHM) || \
3607 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3608 warning(format, __VA_ARGS__); \
3609 } \
3610 } while (0)
3611
3612 #define shm_warning(str) shm_warning_format("%s", str)
3613
3614 #define shm_warning_with_errno(str) \
3615 do { \
3616 int err = errno; \
3617 shm_warning_format(str " (error = %d)", err); \
3618 } while (0)
3619
3620 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3621 assert(is_aligned(bytes, alignment), "Must be divisible by the alignment");
3622
3623 if (!is_aligned(alignment, SHMLBA)) {
3624 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3625 return NULL;
3626 }
3627
3628 // To ensure that we get 'alignment' aligned memory from shmat,
3629 // we pre-reserve aligned virtual memory and then attach to that.
3630
3631 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3632 if (pre_reserved_addr == NULL) {
3633 // Couldn't pre-reserve aligned memory.
3634 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3635 return NULL;
3636 }
3637
3638 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3639 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3640
3641 if ((intptr_t)addr == -1) {
3642 int err = errno;
3643 shm_warning_with_errno("Failed to attach shared memory.");
3644
3645 assert(err != EACCES, "Unexpected error");
3646 assert(err != EIDRM, "Unexpected error");
3647 assert(err != EINVAL, "Unexpected error");
3648
3649 // Since we don't know if the kernel unmapped the pre-reserved memory area
3650 // we can't unmap it, since that would potentially unmap memory that was
3651 // mapped from other threads.
3652 return NULL;
3653 }
3654
3655 return addr;
3656 }
3657
3658 static char* shmat_at_address(int shmid, char* req_addr) {
3659 if (!is_aligned(req_addr, SHMLBA)) {
3660 assert(false, "Requested address needs to be SHMLBA aligned");
3661 return NULL;
3662 }
3663
3664 char* addr = (char*)shmat(shmid, req_addr, 0);
3665
3666 if ((intptr_t)addr == -1) {
3667 shm_warning_with_errno("Failed to attach shared memory.");
3668 return NULL;
3669 }
3670
3671 return addr;
3672 }
3673
3674 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3675 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3676 if (req_addr != NULL) {
3677 assert(is_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3678 assert(is_aligned(req_addr, alignment), "Must be divisible by given alignment");
3679 return shmat_at_address(shmid, req_addr);
3680 }
3681
3682 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3683 // return large page size aligned memory addresses when req_addr == NULL.
3684 // However, if the alignment is larger than the large page size, we have
3685 // to manually ensure that the memory returned is 'alignment' aligned.
3686 if (alignment > os::large_page_size()) {
3687 assert(is_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3688 return shmat_with_alignment(shmid, bytes, alignment);
3689 } else {
3690 return shmat_at_address(shmid, NULL);
3691 }
3692 }
3693
3694 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3695 char* req_addr, bool exec) {
3696 // "exec" is passed in but not used. Creating the shared image for
3697 // the code cache doesn't have an SHM_X executable permission to check.
3698 assert(UseLargePages && UseSHM, "only for SHM large pages");
3699 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3700 assert(is_aligned(req_addr, alignment), "Unaligned address");
3701
3702 if (!is_aligned(bytes, os::large_page_size())) {
3703 return NULL; // Fallback to small pages.
3704 }
3705
3706 // Create a large shared memory region to attach to based on size.
3707 // Currently, size is the total size of the heap.
3708 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3709 if (shmid == -1) {
3710 // Possible reasons for shmget failure:
3711 // 1. shmmax is too small for Java heap.
3712 // > check shmmax value: cat /proc/sys/kernel/shmmax
3713 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3714 // 2. not enough large page memory.
3715 // > check available large pages: cat /proc/meminfo
3716 // > increase amount of large pages:
3717 // echo new_value > /proc/sys/vm/nr_hugepages
3718 // Note 1: different Linux may use different name for this property,
3719 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3720 // Note 2: it's possible there's enough physical memory available but
3721 // they are so fragmented after a long run that they can't
3722 // coalesce into large pages. Try to reserve large pages when
3723 // the system is still "fresh".
3724 shm_warning_with_errno("Failed to reserve shared memory.");
3725 return NULL;
3726 }
3727
3728 // Attach to the region.
3729 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3730
3731 // Remove shmid. If shmat() is successful, the actual shared memory segment
3732 // will be deleted when it's detached by shmdt() or when the process
3733 // terminates. If shmat() is not successful this will remove the shared
3734 // segment immediately.
3735 shmctl(shmid, IPC_RMID, NULL);
3736
3737 return addr;
3738 }
3739
3740 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3741 int error) {
3742 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3743
3744 bool warn_on_failure = UseLargePages &&
3745 (!FLAG_IS_DEFAULT(UseLargePages) ||
3746 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3747 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3748
3749 if (warn_on_failure) {
3750 char msg[128];
3751 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3752 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3753 warning("%s", msg);
3754 }
3755 }
3756
3757 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3758 char* req_addr,
3759 bool exec) {
3760 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3761 assert(is_aligned(bytes, os::large_page_size()), "Unaligned size");
3762 assert(is_aligned(req_addr, os::large_page_size()), "Unaligned address");
3763
3764 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3765 char* addr = (char*)::mmap(req_addr, bytes, prot,
3766 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3767 -1, 0);
3768
3769 if (addr == MAP_FAILED) {
3770 warn_on_large_pages_failure(req_addr, bytes, errno);
3771 return NULL;
3772 }
3773
3774 assert(is_aligned(addr, os::large_page_size()), "Must be");
3775
3776 return addr;
3777 }
3778
3779 // Reserve memory using mmap(MAP_HUGETLB).
3780 // - bytes shall be a multiple of alignment.
3781 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3782 // - alignment sets the alignment at which memory shall be allocated.
3783 // It must be a multiple of allocation granularity.
3784 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3785 // req_addr or NULL.
3786 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3787 size_t alignment,
3788 char* req_addr,
3789 bool exec) {
3790 size_t large_page_size = os::large_page_size();
3791 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3792
3793 assert(is_aligned(req_addr, alignment), "Must be");
3794 assert(is_aligned(bytes, alignment), "Must be");
3795
3796 // First reserve - but not commit - the address range in small pages.
3797 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3798
3799 if (start == NULL) {
3800 return NULL;
3801 }
3802
3803 assert(is_aligned(start, alignment), "Must be");
3804
3805 char* end = start + bytes;
3806
3807 // Find the regions of the allocated chunk that can be promoted to large pages.
3808 char* lp_start = align_up(start, large_page_size);
3809 char* lp_end = align_down(end, large_page_size);
3810
3811 size_t lp_bytes = lp_end - lp_start;
3812
3813 assert(is_aligned(lp_bytes, large_page_size), "Must be");
3814
3815 if (lp_bytes == 0) {
3816 // The mapped region doesn't even span the start and the end of a large page.
3817 // Fall back to allocate a non-special area.
3818 ::munmap(start, end - start);
3819 return NULL;
3820 }
3821
3822 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3823
3824 void* result;
3825
3826 // Commit small-paged leading area.
3827 if (start != lp_start) {
3828 result = ::mmap(start, lp_start - start, prot,
3829 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3830 -1, 0);
3831 if (result == MAP_FAILED) {
3832 ::munmap(lp_start, end - lp_start);
3833 return NULL;
3834 }
3835 }
3836
3837 // Commit large-paged area.
3838 result = ::mmap(lp_start, lp_bytes, prot,
3839 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3840 -1, 0);
3841 if (result == MAP_FAILED) {
3842 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3843 // If the mmap above fails, the large pages region will be unmapped and we
3844 // have regions before and after with small pages. Release these regions.
3845 //
3846 // | mapped | unmapped | mapped |
3847 // ^ ^ ^ ^
3848 // start lp_start lp_end end
3849 //
3850 ::munmap(start, lp_start - start);
3851 ::munmap(lp_end, end - lp_end);
3852 return NULL;
3853 }
3854
3855 // Commit small-paged trailing area.
3856 if (lp_end != end) {
3857 result = ::mmap(lp_end, end - lp_end, prot,
3858 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3859 -1, 0);
3860 if (result == MAP_FAILED) {
3861 ::munmap(start, lp_end - start);
3862 return NULL;
3863 }
3864 }
3865
3866 return start;
3867 }
3868
3869 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3870 size_t alignment,
3871 char* req_addr,
3872 bool exec) {
3873 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3874 assert(is_aligned(req_addr, alignment), "Must be");
3875 assert(is_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3876 assert(is_power_of_2(os::large_page_size()), "Must be");
3877 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3878
3879 if (is_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3880 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3881 } else {
3882 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3883 }
3884 }
3885
3886 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3887 char* req_addr, bool exec) {
3888 assert(UseLargePages, "only for large pages");
3889
3890 char* addr;
3891 if (UseSHM) {
3892 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3893 } else {
3894 assert(UseHugeTLBFS, "must be");
3895 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3896 }
3897
3898 if (addr != NULL) {
3899 if (UseNUMAInterleaving) {
3900 numa_make_global(addr, bytes);
3901 }
3902
3903 // The memory is committed
3904 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3905 }
3906
3907 return addr;
3908 }
3909
3910 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3911 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3912 return shmdt(base) == 0;
3913 }
3914
3915 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3916 return pd_release_memory(base, bytes);
3917 }
3918
3919 bool os::release_memory_special(char* base, size_t bytes) {
3920 bool res;
3921 if (MemTracker::tracking_level() > NMT_minimal) {
3922 Tracker tkr(Tracker::release);
3923 res = os::Linux::release_memory_special_impl(base, bytes);
3924 if (res) {
3925 tkr.record((address)base, bytes);
3926 }
3927
3928 } else {
3929 res = os::Linux::release_memory_special_impl(base, bytes);
3930 }
3931 return res;
3932 }
3933
3934 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3935 assert(UseLargePages, "only for large pages");
3936 bool res;
3937
3938 if (UseSHM) {
3939 res = os::Linux::release_memory_special_shm(base, bytes);
3940 } else {
3941 assert(UseHugeTLBFS, "must be");
3942 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3943 }
3944 return res;
3945 }
3946
3947 size_t os::large_page_size() {
3948 return _large_page_size;
3949 }
3950
3951 // With SysV SHM the entire memory region must be allocated as shared
3952 // memory.
3953 // HugeTLBFS allows application to commit large page memory on demand.
3954 // However, when committing memory with HugeTLBFS fails, the region
3955 // that was supposed to be committed will lose the old reservation
3956 // and allow other threads to steal that memory region. Because of this
3957 // behavior we can't commit HugeTLBFS memory.
3958 bool os::can_commit_large_page_memory() {
3959 return UseTransparentHugePages;
3960 }
3961
3962 bool os::can_execute_large_page_memory() {
3963 return UseTransparentHugePages || UseHugeTLBFS;
3964 }
3965
3966 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr, int file_desc) {
3967 assert(file_desc >= 0, "file_desc is not valid");
3968 char* result = pd_attempt_reserve_memory_at(bytes, requested_addr);
3969 if (result != NULL) {
3970 if (replace_existing_mapping_with_file_mapping(result, bytes, file_desc) == NULL) {
3971 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
3972 }
3973 }
3974 return result;
3975 }
3976
3977 // Reserve memory at an arbitrary address, only if that area is
3978 // available (and not reserved for something else).
3979
3980 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3981 const int max_tries = 10;
3982 char* base[max_tries];
3983 size_t size[max_tries];
3984 const size_t gap = 0x000000;
3985
3986 // Assert only that the size is a multiple of the page size, since
3987 // that's all that mmap requires, and since that's all we really know
3988 // about at this low abstraction level. If we need higher alignment,
3989 // we can either pass an alignment to this method or verify alignment
3990 // in one of the methods further up the call chain. See bug 5044738.
3991 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3992
3993 // Repeatedly allocate blocks until the block is allocated at the
3994 // right spot.
3995
3996 // Linux mmap allows caller to pass an address as hint; give it a try first,
3997 // if kernel honors the hint then we can return immediately.
3998 char * addr = anon_mmap(requested_addr, bytes, false);
3999 if (addr == requested_addr) {
4000 return requested_addr;
4001 }
4002
4003 if (addr != NULL) {
4004 // mmap() is successful but it fails to reserve at the requested address
4005 anon_munmap(addr, bytes);
4006 }
4007
4008 int i;
4009 for (i = 0; i < max_tries; ++i) {
4010 base[i] = reserve_memory(bytes);
4011
4012 if (base[i] != NULL) {
4013 // Is this the block we wanted?
4014 if (base[i] == requested_addr) {
4015 size[i] = bytes;
4016 break;
4017 }
4018
4019 // Does this overlap the block we wanted? Give back the overlapped
4020 // parts and try again.
4021
4022 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
4023 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
4024 unmap_memory(base[i], top_overlap);
4025 base[i] += top_overlap;
4026 size[i] = bytes - top_overlap;
4027 } else {
4028 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
4029 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
4030 unmap_memory(requested_addr, bottom_overlap);
4031 size[i] = bytes - bottom_overlap;
4032 } else {
4033 size[i] = bytes;
4034 }
4035 }
4036 }
4037 }
4038
4039 // Give back the unused reserved pieces.
4040
4041 for (int j = 0; j < i; ++j) {
4042 if (base[j] != NULL) {
4043 unmap_memory(base[j], size[j]);
4044 }
4045 }
4046
4047 if (i < max_tries) {
4048 return requested_addr;
4049 } else {
4050 return NULL;
4051 }
4052 }
4053
4054 size_t os::read(int fd, void *buf, unsigned int nBytes) {
4055 return ::read(fd, buf, nBytes);
4056 }
4057
4058 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
4059 return ::pread(fd, buf, nBytes, offset);
4060 }
4061
4062 // Short sleep, direct OS call.
4063 //
4064 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
4065 // sched_yield(2) will actually give up the CPU:
4066 //
4067 // * Alone on this pariticular CPU, keeps running.
4068 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
4069 // (pre 2.6.39).
4070 //
4071 // So calling this with 0 is an alternative.
4072 //
4073 void os::naked_short_sleep(jlong ms) {
4074 struct timespec req;
4075
4076 assert(ms < 1000, "Un-interruptable sleep, short time use only");
4077 req.tv_sec = 0;
4078 if (ms > 0) {
4079 req.tv_nsec = (ms % 1000) * 1000000;
4080 } else {
4081 req.tv_nsec = 1;
4082 }
4083
4084 nanosleep(&req, NULL);
4085
4086 return;
4087 }
4088
4089 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4090 void os::infinite_sleep() {
4091 while (true) { // sleep forever ...
4092 ::sleep(100); // ... 100 seconds at a time
4093 }
4094 }
4095
4096 // Used to convert frequent JVM_Yield() to nops
4097 bool os::dont_yield() {
4098 return DontYieldALot;
4099 }
4100
4101 void os::naked_yield() {
4102 sched_yield();
4103 }
4104
4105 ////////////////////////////////////////////////////////////////////////////////
4106 // thread priority support
4107
4108 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4109 // only supports dynamic priority, static priority must be zero. For real-time
4110 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4111 // However, for large multi-threaded applications, SCHED_RR is not only slower
4112 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4113 // of 5 runs - Sep 2005).
4114 //
4115 // The following code actually changes the niceness of kernel-thread/LWP. It
4116 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4117 // not the entire user process, and user level threads are 1:1 mapped to kernel
4118 // threads. It has always been the case, but could change in the future. For
4119 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4120 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
4121
4122 int os::java_to_os_priority[CriticalPriority + 1] = {
4123 19, // 0 Entry should never be used
4124
4125 4, // 1 MinPriority
4126 3, // 2
4127 2, // 3
4128
4129 1, // 4
4130 0, // 5 NormPriority
4131 -1, // 6
4132
4133 -2, // 7
4134 -3, // 8
4135 -4, // 9 NearMaxPriority
4136
4137 -5, // 10 MaxPriority
4138
4139 -5 // 11 CriticalPriority
4140 };
4141
4142 static int prio_init() {
4143 if (ThreadPriorityPolicy == 1) {
4144 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
4145 // if effective uid is not root. Perhaps, a more elegant way of doing
4146 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
4147 if (geteuid() != 0) {
4148 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4149 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
4150 }
4151 ThreadPriorityPolicy = 0;
4152 }
4153 }
4154 if (UseCriticalJavaThreadPriority) {
4155 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4156 }
4157 return 0;
4158 }
4159
4160 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4161 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4162
4163 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4164 return (ret == 0) ? OS_OK : OS_ERR;
4165 }
4166
4167 OSReturn os::get_native_priority(const Thread* const thread,
4168 int *priority_ptr) {
4169 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4170 *priority_ptr = java_to_os_priority[NormPriority];
4171 return OS_OK;
4172 }
4173
4174 errno = 0;
4175 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4176 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4177 }
4178
4179 // Hint to the underlying OS that a task switch would not be good.
4180 // Void return because it's a hint and can fail.
4181 void os::hint_no_preempt() {}
4182
4183 ////////////////////////////////////////////////////////////////////////////////
4184 // suspend/resume support
4185
4186 // The low-level signal-based suspend/resume support is a remnant from the
4187 // old VM-suspension that used to be for java-suspension, safepoints etc,
4188 // within hotspot. Currently used by JFR's OSThreadSampler
4189 //
4190 // The remaining code is greatly simplified from the more general suspension
4191 // code that used to be used.
4192 //
4193 // The protocol is quite simple:
4194 // - suspend:
4195 // - sends a signal to the target thread
4196 // - polls the suspend state of the osthread using a yield loop
4197 // - target thread signal handler (SR_handler) sets suspend state
4198 // and blocks in sigsuspend until continued
4199 // - resume:
4200 // - sets target osthread state to continue
4201 // - sends signal to end the sigsuspend loop in the SR_handler
4202 //
4203 // Note that the SR_lock plays no role in this suspend/resume protocol,
4204 // but is checked for NULL in SR_handler as a thread termination indicator.
4205 // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
4206 //
4207 // Note that resume_clear_context() and suspend_save_context() are needed
4208 // by SR_handler(), so that fetch_frame_from_ucontext() works,
4209 // which in part is used by:
4210 // - Forte Analyzer: AsyncGetCallTrace()
4211 // - StackBanging: get_frame_at_stack_banging_point()
4212
4213 static void resume_clear_context(OSThread *osthread) {
4214 osthread->set_ucontext(NULL);
4215 osthread->set_siginfo(NULL);
4216 }
4217
4218 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4219 ucontext_t* context) {
4220 osthread->set_ucontext(context);
4221 osthread->set_siginfo(siginfo);
4222 }
4223
4224 // Handler function invoked when a thread's execution is suspended or
4225 // resumed. We have to be careful that only async-safe functions are
4226 // called here (Note: most pthread functions are not async safe and
4227 // should be avoided.)
4228 //
4229 // Note: sigwait() is a more natural fit than sigsuspend() from an
4230 // interface point of view, but sigwait() prevents the signal hander
4231 // from being run. libpthread would get very confused by not having
4232 // its signal handlers run and prevents sigwait()'s use with the
4233 // mutex granting granting signal.
4234 //
4235 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4236 //
4237 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4238 // Save and restore errno to avoid confusing native code with EINTR
4239 // after sigsuspend.
4240 int old_errno = errno;
4241
4242 Thread* thread = Thread::current_or_null_safe();
4243 assert(thread != NULL, "Missing current thread in SR_handler");
4244
4245 // On some systems we have seen signal delivery get "stuck" until the signal
4246 // mask is changed as part of thread termination. Check that the current thread
4247 // has not already terminated (via SR_lock()) - else the following assertion
4248 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4249 // destructor has completed.
4250
4251 if (thread->SR_lock() == NULL) {
4252 return;
4253 }
4254
4255 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4256
4257 OSThread* osthread = thread->osthread();
4258
4259 os::SuspendResume::State current = osthread->sr.state();
4260 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4261 suspend_save_context(osthread, siginfo, context);
4262
4263 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4264 os::SuspendResume::State state = osthread->sr.suspended();
4265 if (state == os::SuspendResume::SR_SUSPENDED) {
4266 sigset_t suspend_set; // signals for sigsuspend()
4267 sigemptyset(&suspend_set);
4268 // get current set of blocked signals and unblock resume signal
4269 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4270 sigdelset(&suspend_set, SR_signum);
4271
4272 sr_semaphore.signal();
4273 // wait here until we are resumed
4274 while (1) {
4275 sigsuspend(&suspend_set);
4276
4277 os::SuspendResume::State result = osthread->sr.running();
4278 if (result == os::SuspendResume::SR_RUNNING) {
4279 sr_semaphore.signal();
4280 break;
4281 }
4282 }
4283
4284 } else if (state == os::SuspendResume::SR_RUNNING) {
4285 // request was cancelled, continue
4286 } else {
4287 ShouldNotReachHere();
4288 }
4289
4290 resume_clear_context(osthread);
4291 } else if (current == os::SuspendResume::SR_RUNNING) {
4292 // request was cancelled, continue
4293 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4294 // ignore
4295 } else {
4296 // ignore
4297 }
4298
4299 errno = old_errno;
4300 }
4301
4302 static int SR_initialize() {
4303 struct sigaction act;
4304 char *s;
4305
4306 // Get signal number to use for suspend/resume
4307 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4308 int sig = ::strtol(s, 0, 10);
4309 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4310 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4311 SR_signum = sig;
4312 } else {
4313 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4314 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4315 }
4316 }
4317
4318 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4319 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4320
4321 sigemptyset(&SR_sigset);
4322 sigaddset(&SR_sigset, SR_signum);
4323
4324 // Set up signal handler for suspend/resume
4325 act.sa_flags = SA_RESTART|SA_SIGINFO;
4326 act.sa_handler = (void (*)(int)) SR_handler;
4327
4328 // SR_signum is blocked by default.
4329 // 4528190 - We also need to block pthread restart signal (32 on all
4330 // supported Linux platforms). Note that LinuxThreads need to block
4331 // this signal for all threads to work properly. So we don't have
4332 // to use hard-coded signal number when setting up the mask.
4333 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4334
4335 if (sigaction(SR_signum, &act, 0) == -1) {
4336 return -1;
4337 }
4338
4339 // Save signal flag
4340 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4341 return 0;
4342 }
4343
4344 static int sr_notify(OSThread* osthread) {
4345 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4346 assert_status(status == 0, status, "pthread_kill");
4347 return status;
4348 }
4349
4350 // "Randomly" selected value for how long we want to spin
4351 // before bailing out on suspending a thread, also how often
4352 // we send a signal to a thread we want to resume
4353 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4354 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4355
4356 // returns true on success and false on error - really an error is fatal
4357 // but this seems the normal response to library errors
4358 static bool do_suspend(OSThread* osthread) {
4359 assert(osthread->sr.is_running(), "thread should be running");
4360 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4361
4362 // mark as suspended and send signal
4363 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4364 // failed to switch, state wasn't running?
4365 ShouldNotReachHere();
4366 return false;
4367 }
4368
4369 if (sr_notify(osthread) != 0) {
4370 ShouldNotReachHere();
4371 }
4372
4373 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4374 while (true) {
4375 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) {
4376 break;
4377 } else {
4378 // timeout
4379 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4380 if (cancelled == os::SuspendResume::SR_RUNNING) {
4381 return false;
4382 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4383 // make sure that we consume the signal on the semaphore as well
4384 sr_semaphore.wait();
4385 break;
4386 } else {
4387 ShouldNotReachHere();
4388 return false;
4389 }
4390 }
4391 }
4392
4393 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4394 return true;
4395 }
4396
4397 static void do_resume(OSThread* osthread) {
4398 assert(osthread->sr.is_suspended(), "thread should be suspended");
4399 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4400
4401 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4402 // failed to switch to WAKEUP_REQUEST
4403 ShouldNotReachHere();
4404 return;
4405 }
4406
4407 while (true) {
4408 if (sr_notify(osthread) == 0) {
4409 if (sr_semaphore.timedwait(create_semaphore_timespec(0, 2 * NANOSECS_PER_MILLISEC))) {
4410 if (osthread->sr.is_running()) {
4411 return;
4412 }
4413 }
4414 } else {
4415 ShouldNotReachHere();
4416 }
4417 }
4418
4419 guarantee(osthread->sr.is_running(), "Must be running!");
4420 }
4421
4422 ///////////////////////////////////////////////////////////////////////////////////
4423 // signal handling (except suspend/resume)
4424
4425 // This routine may be used by user applications as a "hook" to catch signals.
4426 // The user-defined signal handler must pass unrecognized signals to this
4427 // routine, and if it returns true (non-zero), then the signal handler must
4428 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4429 // routine will never retun false (zero), but instead will execute a VM panic
4430 // routine kill the process.
4431 //
4432 // If this routine returns false, it is OK to call it again. This allows
4433 // the user-defined signal handler to perform checks either before or after
4434 // the VM performs its own checks. Naturally, the user code would be making
4435 // a serious error if it tried to handle an exception (such as a null check
4436 // or breakpoint) that the VM was generating for its own correct operation.
4437 //
4438 // This routine may recognize any of the following kinds of signals:
4439 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4440 // It should be consulted by handlers for any of those signals.
4441 //
4442 // The caller of this routine must pass in the three arguments supplied
4443 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4444 // field of the structure passed to sigaction(). This routine assumes that
4445 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4446 //
4447 // Note that the VM will print warnings if it detects conflicting signal
4448 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4449 //
4450 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4451 siginfo_t* siginfo,
4452 void* ucontext,
4453 int abort_if_unrecognized);
4454
4455 void signalHandler(int sig, siginfo_t* info, void* uc) {
4456 assert(info != NULL && uc != NULL, "it must be old kernel");
4457 int orig_errno = errno; // Preserve errno value over signal handler.
4458 JVM_handle_linux_signal(sig, info, uc, true);
4459 errno = orig_errno;
4460 }
4461
4462
4463 // This boolean allows users to forward their own non-matching signals
4464 // to JVM_handle_linux_signal, harmlessly.
4465 bool os::Linux::signal_handlers_are_installed = false;
4466
4467 // For signal-chaining
4468 struct sigaction sigact[NSIG];
4469 uint64_t sigs = 0;
4470 #if (64 < NSIG-1)
4471 #error "Not all signals can be encoded in sigs. Adapt its type!"
4472 #endif
4473 bool os::Linux::libjsig_is_loaded = false;
4474 typedef struct sigaction *(*get_signal_t)(int);
4475 get_signal_t os::Linux::get_signal_action = NULL;
4476
4477 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4478 struct sigaction *actp = NULL;
4479
4480 if (libjsig_is_loaded) {
4481 // Retrieve the old signal handler from libjsig
4482 actp = (*get_signal_action)(sig);
4483 }
4484 if (actp == NULL) {
4485 // Retrieve the preinstalled signal handler from jvm
4486 actp = get_preinstalled_handler(sig);
4487 }
4488
4489 return actp;
4490 }
4491
4492 static bool call_chained_handler(struct sigaction *actp, int sig,
4493 siginfo_t *siginfo, void *context) {
4494 // Call the old signal handler
4495 if (actp->sa_handler == SIG_DFL) {
4496 // It's more reasonable to let jvm treat it as an unexpected exception
4497 // instead of taking the default action.
4498 return false;
4499 } else if (actp->sa_handler != SIG_IGN) {
4500 if ((actp->sa_flags & SA_NODEFER) == 0) {
4501 // automaticlly block the signal
4502 sigaddset(&(actp->sa_mask), sig);
4503 }
4504
4505 sa_handler_t hand = NULL;
4506 sa_sigaction_t sa = NULL;
4507 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4508 // retrieve the chained handler
4509 if (siginfo_flag_set) {
4510 sa = actp->sa_sigaction;
4511 } else {
4512 hand = actp->sa_handler;
4513 }
4514
4515 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4516 actp->sa_handler = SIG_DFL;
4517 }
4518
4519 // try to honor the signal mask
4520 sigset_t oset;
4521 sigemptyset(&oset);
4522 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4523
4524 // call into the chained handler
4525 if (siginfo_flag_set) {
4526 (*sa)(sig, siginfo, context);
4527 } else {
4528 (*hand)(sig);
4529 }
4530
4531 // restore the signal mask
4532 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4533 }
4534 // Tell jvm's signal handler the signal is taken care of.
4535 return true;
4536 }
4537
4538 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4539 bool chained = false;
4540 // signal-chaining
4541 if (UseSignalChaining) {
4542 struct sigaction *actp = get_chained_signal_action(sig);
4543 if (actp != NULL) {
4544 chained = call_chained_handler(actp, sig, siginfo, context);
4545 }
4546 }
4547 return chained;
4548 }
4549
4550 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4551 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4552 return &sigact[sig];
4553 }
4554 return NULL;
4555 }
4556
4557 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4558 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4559 sigact[sig] = oldAct;
4560 sigs |= (uint64_t)1 << (sig-1);
4561 }
4562
4563 // for diagnostic
4564 int sigflags[NSIG];
4565
4566 int os::Linux::get_our_sigflags(int sig) {
4567 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4568 return sigflags[sig];
4569 }
4570
4571 void os::Linux::set_our_sigflags(int sig, int flags) {
4572 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4573 if (sig > 0 && sig < NSIG) {
4574 sigflags[sig] = flags;
4575 }
4576 }
4577
4578 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4579 // Check for overwrite.
4580 struct sigaction oldAct;
4581 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4582
4583 void* oldhand = oldAct.sa_sigaction
4584 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4585 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4586 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4587 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4588 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4589 if (AllowUserSignalHandlers || !set_installed) {
4590 // Do not overwrite; user takes responsibility to forward to us.
4591 return;
4592 } else if (UseSignalChaining) {
4593 // save the old handler in jvm
4594 save_preinstalled_handler(sig, oldAct);
4595 // libjsig also interposes the sigaction() call below and saves the
4596 // old sigaction on it own.
4597 } else {
4598 fatal("Encountered unexpected pre-existing sigaction handler "
4599 "%#lx for signal %d.", (long)oldhand, sig);
4600 }
4601 }
4602
4603 struct sigaction sigAct;
4604 sigfillset(&(sigAct.sa_mask));
4605 sigAct.sa_handler = SIG_DFL;
4606 if (!set_installed) {
4607 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4608 } else {
4609 sigAct.sa_sigaction = signalHandler;
4610 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4611 }
4612 // Save flags, which are set by ours
4613 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4614 sigflags[sig] = sigAct.sa_flags;
4615
4616 int ret = sigaction(sig, &sigAct, &oldAct);
4617 assert(ret == 0, "check");
4618
4619 void* oldhand2 = oldAct.sa_sigaction
4620 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4621 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4622 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4623 }
4624
4625 // install signal handlers for signals that HotSpot needs to
4626 // handle in order to support Java-level exception handling.
4627
4628 void os::Linux::install_signal_handlers() {
4629 if (!signal_handlers_are_installed) {
4630 signal_handlers_are_installed = true;
4631
4632 // signal-chaining
4633 typedef void (*signal_setting_t)();
4634 signal_setting_t begin_signal_setting = NULL;
4635 signal_setting_t end_signal_setting = NULL;
4636 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4637 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4638 if (begin_signal_setting != NULL) {
4639 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4640 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4641 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4642 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4643 libjsig_is_loaded = true;
4644 assert(UseSignalChaining, "should enable signal-chaining");
4645 }
4646 if (libjsig_is_loaded) {
4647 // Tell libjsig jvm is setting signal handlers
4648 (*begin_signal_setting)();
4649 }
4650
4651 set_signal_handler(SIGSEGV, true);
4652 set_signal_handler(SIGPIPE, true);
4653 set_signal_handler(SIGBUS, true);
4654 set_signal_handler(SIGILL, true);
4655 set_signal_handler(SIGFPE, true);
4656 #if defined(PPC64)
4657 set_signal_handler(SIGTRAP, true);
4658 #endif
4659 set_signal_handler(SIGXFSZ, true);
4660
4661 if (libjsig_is_loaded) {
4662 // Tell libjsig jvm finishes setting signal handlers
4663 (*end_signal_setting)();
4664 }
4665
4666 // We don't activate signal checker if libjsig is in place, we trust ourselves
4667 // and if UserSignalHandler is installed all bets are off.
4668 // Log that signal checking is off only if -verbose:jni is specified.
4669 if (CheckJNICalls) {
4670 if (libjsig_is_loaded) {
4671 if (PrintJNIResolving) {
4672 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4673 }
4674 check_signals = false;
4675 }
4676 if (AllowUserSignalHandlers) {
4677 if (PrintJNIResolving) {
4678 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4679 }
4680 check_signals = false;
4681 }
4682 }
4683 }
4684 }
4685
4686 // This is the fastest way to get thread cpu time on Linux.
4687 // Returns cpu time (user+sys) for any thread, not only for current.
4688 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4689 // It might work on 2.6.10+ with a special kernel/glibc patch.
4690 // For reference, please, see IEEE Std 1003.1-2004:
4691 // http://www.unix.org/single_unix_specification
4692
4693 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4694 struct timespec tp;
4695 int rc = os::Linux::clock_gettime(clockid, &tp);
4696 assert(rc == 0, "clock_gettime is expected to return 0 code");
4697
4698 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4699 }
4700
4701 void os::Linux::initialize_os_info() {
4702 assert(_os_version == 0, "OS info already initialized");
4703
4704 struct utsname _uname;
4705
4706 uint32_t major;
4707 uint32_t minor;
4708 uint32_t fix;
4709
4710 int rc;
4711
4712 // Kernel version is unknown if
4713 // verification below fails.
4714 _os_version = 0x01000000;
4715
4716 rc = uname(&_uname);
4717 if (rc != -1) {
4718
4719 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4720 if (rc == 3) {
4721
4722 if (major < 256 && minor < 256 && fix < 256) {
4723 // Kernel version format is as expected,
4724 // set it overriding unknown state.
4725 _os_version = (major << 16) |
4726 (minor << 8 ) |
4727 (fix << 0 ) ;
4728 }
4729 }
4730 }
4731 }
4732
4733 uint32_t os::Linux::os_version() {
4734 assert(_os_version != 0, "not initialized");
4735 return _os_version & 0x00FFFFFF;
4736 }
4737
4738 bool os::Linux::os_version_is_known() {
4739 assert(_os_version != 0, "not initialized");
4740 return _os_version & 0x01000000 ? false : true;
4741 }
4742
4743 /////
4744 // glibc on Linux platform uses non-documented flag
4745 // to indicate, that some special sort of signal
4746 // trampoline is used.
4747 // We will never set this flag, and we should
4748 // ignore this flag in our diagnostic
4749 #ifdef SIGNIFICANT_SIGNAL_MASK
4750 #undef SIGNIFICANT_SIGNAL_MASK
4751 #endif
4752 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4753
4754 static const char* get_signal_handler_name(address handler,
4755 char* buf, int buflen) {
4756 int offset = 0;
4757 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4758 if (found) {
4759 // skip directory names
4760 const char *p1, *p2;
4761 p1 = buf;
4762 size_t len = strlen(os::file_separator());
4763 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4764 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4765 } else {
4766 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4767 }
4768 return buf;
4769 }
4770
4771 static void print_signal_handler(outputStream* st, int sig,
4772 char* buf, size_t buflen) {
4773 struct sigaction sa;
4774
4775 sigaction(sig, NULL, &sa);
4776
4777 // See comment for SIGNIFICANT_SIGNAL_MASK define
4778 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4779
4780 st->print("%s: ", os::exception_name(sig, buf, buflen));
4781
4782 address handler = (sa.sa_flags & SA_SIGINFO)
4783 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4784 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4785
4786 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4787 st->print("SIG_DFL");
4788 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4789 st->print("SIG_IGN");
4790 } else {
4791 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4792 }
4793
4794 st->print(", sa_mask[0]=");
4795 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4796
4797 address rh = VMError::get_resetted_sighandler(sig);
4798 // May be, handler was resetted by VMError?
4799 if (rh != NULL) {
4800 handler = rh;
4801 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4802 }
4803
4804 st->print(", sa_flags=");
4805 os::Posix::print_sa_flags(st, sa.sa_flags);
4806
4807 // Check: is it our handler?
4808 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4809 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4810 // It is our signal handler
4811 // check for flags, reset system-used one!
4812 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4813 st->print(
4814 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4815 os::Linux::get_our_sigflags(sig));
4816 }
4817 }
4818 st->cr();
4819 }
4820
4821
4822 #define DO_SIGNAL_CHECK(sig) \
4823 do { \
4824 if (!sigismember(&check_signal_done, sig)) { \
4825 os::Linux::check_signal_handler(sig); \
4826 } \
4827 } while (0)
4828
4829 // This method is a periodic task to check for misbehaving JNI applications
4830 // under CheckJNI, we can add any periodic checks here
4831
4832 void os::run_periodic_checks() {
4833 if (check_signals == false) return;
4834
4835 // SEGV and BUS if overridden could potentially prevent
4836 // generation of hs*.log in the event of a crash, debugging
4837 // such a case can be very challenging, so we absolutely
4838 // check the following for a good measure:
4839 DO_SIGNAL_CHECK(SIGSEGV);
4840 DO_SIGNAL_CHECK(SIGILL);
4841 DO_SIGNAL_CHECK(SIGFPE);
4842 DO_SIGNAL_CHECK(SIGBUS);
4843 DO_SIGNAL_CHECK(SIGPIPE);
4844 DO_SIGNAL_CHECK(SIGXFSZ);
4845 #if defined(PPC64)
4846 DO_SIGNAL_CHECK(SIGTRAP);
4847 #endif
4848
4849 // ReduceSignalUsage allows the user to override these handlers
4850 // see comments at the very top and jvm_md.h
4851 if (!ReduceSignalUsage) {
4852 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4853 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4854 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4855 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4856 }
4857
4858 DO_SIGNAL_CHECK(SR_signum);
4859 }
4860
4861 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4862
4863 static os_sigaction_t os_sigaction = NULL;
4864
4865 void os::Linux::check_signal_handler(int sig) {
4866 char buf[O_BUFLEN];
4867 address jvmHandler = NULL;
4868
4869
4870 struct sigaction act;
4871 if (os_sigaction == NULL) {
4872 // only trust the default sigaction, in case it has been interposed
4873 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4874 if (os_sigaction == NULL) return;
4875 }
4876
4877 os_sigaction(sig, (struct sigaction*)NULL, &act);
4878
4879
4880 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4881
4882 address thisHandler = (act.sa_flags & SA_SIGINFO)
4883 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4884 : CAST_FROM_FN_PTR(address, act.sa_handler);
4885
4886
4887 switch (sig) {
4888 case SIGSEGV:
4889 case SIGBUS:
4890 case SIGFPE:
4891 case SIGPIPE:
4892 case SIGILL:
4893 case SIGXFSZ:
4894 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4895 break;
4896
4897 case SHUTDOWN1_SIGNAL:
4898 case SHUTDOWN2_SIGNAL:
4899 case SHUTDOWN3_SIGNAL:
4900 case BREAK_SIGNAL:
4901 jvmHandler = (address)user_handler();
4902 break;
4903
4904 default:
4905 if (sig == SR_signum) {
4906 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4907 } else {
4908 return;
4909 }
4910 break;
4911 }
4912
4913 if (thisHandler != jvmHandler) {
4914 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4915 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4916 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4917 // No need to check this sig any longer
4918 sigaddset(&check_signal_done, sig);
4919 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4920 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4921 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4922 exception_name(sig, buf, O_BUFLEN));
4923 }
4924 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4925 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4926 tty->print("expected:");
4927 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4928 tty->cr();
4929 tty->print(" found:");
4930 os::Posix::print_sa_flags(tty, act.sa_flags);
4931 tty->cr();
4932 // No need to check this sig any longer
4933 sigaddset(&check_signal_done, sig);
4934 }
4935
4936 // Dump all the signal
4937 if (sigismember(&check_signal_done, sig)) {
4938 print_signal_handlers(tty, buf, O_BUFLEN);
4939 }
4940 }
4941
4942 extern void report_error(char* file_name, int line_no, char* title,
4943 char* format, ...);
4944
4945 // this is called _before_ most of the global arguments have been parsed
4946 void os::init(void) {
4947 char dummy; // used to get a guess on initial stack address
4948
4949 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4950
4951 init_random(1234567);
4952
4953 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4954 if (Linux::page_size() == -1) {
4955 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4956 os::strerror(errno));
4957 }
4958 init_page_sizes((size_t) Linux::page_size());
4959
4960 Linux::initialize_system_info();
4961
4962 Linux::initialize_os_info();
4963
4964 // _main_thread points to the thread that created/loaded the JVM.
4965 Linux::_main_thread = pthread_self();
4966
4967 Linux::clock_init();
4968 initial_time_count = javaTimeNanos();
4969
4970 // retrieve entry point for pthread_setname_np
4971 Linux::_pthread_setname_np =
4972 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4973
4974 os::Posix::init();
4975 }
4976
4977 // To install functions for atexit system call
4978 extern "C" {
4979 static void perfMemory_exit_helper() {
4980 perfMemory_exit();
4981 }
4982 }
4983
4984 void os::pd_init_container_support() {
4985 OSContainer::init();
4986 }
4987
4988 // this is called _after_ the global arguments have been parsed
4989 jint os::init_2(void) {
4990
4991 os::Posix::init_2();
4992
4993 Linux::fast_thread_clock_init();
4994
4995 // initialize suspend/resume support - must do this before signal_sets_init()
4996 if (SR_initialize() != 0) {
4997 perror("SR_initialize failed");
4998 return JNI_ERR;
4999 }
5000
5001 Linux::signal_sets_init();
5002 Linux::install_signal_handlers();
5003
5004 // Check and sets minimum stack sizes against command line options
5005 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
5006 return JNI_ERR;
5007 }
5008
5009 suppress_primordial_thread_resolution = Arguments::created_by_java_launcher();
5010 if (!suppress_primordial_thread_resolution) {
5011 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5012 }
5013
5014 #if defined(IA32)
5015 workaround_expand_exec_shield_cs_limit();
5016 #endif
5017
5018 Linux::libpthread_init();
5019 Linux::sched_getcpu_init();
5020 log_info(os)("HotSpot is running with %s, %s",
5021 Linux::glibc_version(), Linux::libpthread_version());
5022
5023 if (UseNUMA) {
5024 if (!Linux::libnuma_init()) {
5025 UseNUMA = false;
5026 } else {
5027 if ((Linux::numa_max_node() < 1)) {
5028 // There's only one node(they start from 0), disable NUMA.
5029 UseNUMA = false;
5030 }
5031 }
5032
5033 if (UseParallelGC && UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5034 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5035 // we can make the adaptive lgrp chunk resizing work. If the user specified both
5036 // UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn
5037 // and disable adaptive resizing.
5038 if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
5039 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, "
5040 "disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
5041 UseAdaptiveSizePolicy = false;
5042 UseAdaptiveNUMAChunkSizing = false;
5043 }
5044 }
5045
5046 if (!UseNUMA && ForceNUMA) {
5047 UseNUMA = true;
5048 }
5049 }
5050
5051 if (MaxFDLimit) {
5052 // set the number of file descriptors to max. print out error
5053 // if getrlimit/setrlimit fails but continue regardless.
5054 struct rlimit nbr_files;
5055 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5056 if (status != 0) {
5057 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
5058 } else {
5059 nbr_files.rlim_cur = nbr_files.rlim_max;
5060 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5061 if (status != 0) {
5062 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
5063 }
5064 }
5065 }
5066
5067 // Initialize lock used to serialize thread creation (see os::create_thread)
5068 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
5069
5070 // at-exit methods are called in the reverse order of their registration.
5071 // atexit functions are called on return from main or as a result of a
5072 // call to exit(3C). There can be only 32 of these functions registered
5073 // and atexit() does not set errno.
5074
5075 if (PerfAllowAtExitRegistration) {
5076 // only register atexit functions if PerfAllowAtExitRegistration is set.
5077 // atexit functions can be delayed until process exit time, which
5078 // can be problematic for embedded VM situations. Embedded VMs should
5079 // call DestroyJavaVM() to assure that VM resources are released.
5080
5081 // note: perfMemory_exit_helper atexit function may be removed in
5082 // the future if the appropriate cleanup code can be added to the
5083 // VM_Exit VMOperation's doit method.
5084 if (atexit(perfMemory_exit_helper) != 0) {
5085 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5086 }
5087 }
5088
5089 // initialize thread priority policy
5090 prio_init();
5091
5092 if (!FLAG_IS_DEFAULT(AllocateHeapAt)) {
5093 set_coredump_filter(false /*largepages*/, true /*dax_shared*/);
5094 }
5095 return JNI_OK;
5096 }
5097
5098 // Mark the polling page as unreadable
5099 void os::make_polling_page_unreadable(void) {
5100 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
5101 fatal("Could not disable polling page");
5102 }
5103 }
5104
5105 // Mark the polling page as readable
5106 void os::make_polling_page_readable(void) {
5107 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5108 fatal("Could not enable polling page");
5109 }
5110 }
5111
5112 // older glibc versions don't have this macro (which expands to
5113 // an optimized bit-counting function) so we have to roll our own
5114 #ifndef CPU_COUNT
5115
5116 static int _cpu_count(const cpu_set_t* cpus) {
5117 int count = 0;
5118 // only look up to the number of configured processors
5119 for (int i = 0; i < os::processor_count(); i++) {
5120 if (CPU_ISSET(i, cpus)) {
5121 count++;
5122 }
5123 }
5124 return count;
5125 }
5126
5127 #define CPU_COUNT(cpus) _cpu_count(cpus)
5128
5129 #endif // CPU_COUNT
5130
5131 // Get the current number of available processors for this process.
5132 // This value can change at any time during a process's lifetime.
5133 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5134 // If it appears there may be more than 1024 processors then we do a
5135 // dynamic check - see 6515172 for details.
5136 // If anything goes wrong we fallback to returning the number of online
5137 // processors - which can be greater than the number available to the process.
5138 int os::Linux::active_processor_count() {
5139 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5140 cpu_set_t* cpus_p = &cpus;
5141 int cpus_size = sizeof(cpu_set_t);
5142
5143 int configured_cpus = os::processor_count(); // upper bound on available cpus
5144 int cpu_count = 0;
5145
5146 // old build platforms may not support dynamic cpu sets
5147 #ifdef CPU_ALLOC
5148
5149 // To enable easy testing of the dynamic path on different platforms we
5150 // introduce a diagnostic flag: UseCpuAllocPath
5151 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5152 // kernel may use a mask bigger than cpu_set_t
5153 log_trace(os)("active_processor_count: using dynamic path %s"
5154 "- configured processors: %d",
5155 UseCpuAllocPath ? "(forced) " : "",
5156 configured_cpus);
5157 cpus_p = CPU_ALLOC(configured_cpus);
5158 if (cpus_p != NULL) {
5159 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5160 // zero it just to be safe
5161 CPU_ZERO_S(cpus_size, cpus_p);
5162 }
5163 else {
5164 // failed to allocate so fallback to online cpus
5165 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5166 log_trace(os)("active_processor_count: "
5167 "CPU_ALLOC failed (%s) - using "
5168 "online processor count: %d",
5169 os::strerror(errno), online_cpus);
5170 return online_cpus;
5171 }
5172 }
5173 else {
5174 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5175 configured_cpus);
5176 }
5177 #else // CPU_ALLOC
5178 // these stubs won't be executed
5179 #define CPU_COUNT_S(size, cpus) -1
5180 #define CPU_FREE(cpus)
5181
5182 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5183 configured_cpus);
5184 #endif // CPU_ALLOC
5185
5186 // pid 0 means the current thread - which we have to assume represents the process
5187 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5188 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5189 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5190 }
5191 else {
5192 cpu_count = CPU_COUNT(cpus_p);
5193 }
5194 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5195 }
5196 else {
5197 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5198 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5199 "which may exceed available processors", os::strerror(errno), cpu_count);
5200 }
5201
5202 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5203 CPU_FREE(cpus_p);
5204 }
5205
5206 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5207 return cpu_count;
5208 }
5209
5210 // Determine the active processor count from one of
5211 // three different sources:
5212 //
5213 // 1. User option -XX:ActiveProcessorCount
5214 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5215 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5216 //
5217 // Option 1, if specified, will always override.
5218 // If the cgroup subsystem is active and configured, we
5219 // will return the min of the cgroup and option 2 results.
5220 // This is required since tools, such as numactl, that
5221 // alter cpu affinity do not update cgroup subsystem
5222 // cpuset configuration files.
5223 int os::active_processor_count() {
5224 // User has overridden the number of active processors
5225 if (ActiveProcessorCount > 0) {
5226 log_trace(os)("active_processor_count: "
5227 "active processor count set by user : %d",
5228 ActiveProcessorCount);
5229 return ActiveProcessorCount;
5230 }
5231
5232 int active_cpus;
5233 if (OSContainer::is_containerized()) {
5234 active_cpus = OSContainer::active_processor_count();
5235 log_trace(os)("active_processor_count: determined by OSContainer: %d",
5236 active_cpus);
5237 } else {
5238 active_cpus = os::Linux::active_processor_count();
5239 }
5240
5241 return active_cpus;
5242 }
5243
5244 void os::set_native_thread_name(const char *name) {
5245 if (Linux::_pthread_setname_np) {
5246 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5247 snprintf(buf, sizeof(buf), "%s", name);
5248 buf[sizeof(buf) - 1] = '\0';
5249 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5250 // ERANGE should not happen; all other errors should just be ignored.
5251 assert(rc != ERANGE, "pthread_setname_np failed");
5252 }
5253 }
5254
5255 bool os::distribute_processes(uint length, uint* distribution) {
5256 // Not yet implemented.
5257 return false;
5258 }
5259
5260 bool os::bind_to_processor(uint processor_id) {
5261 // Not yet implemented.
5262 return false;
5263 }
5264
5265 ///
5266
5267 void os::SuspendedThreadTask::internal_do_task() {
5268 if (do_suspend(_thread->osthread())) {
5269 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5270 do_task(context);
5271 do_resume(_thread->osthread());
5272 }
5273 }
5274
5275 ////////////////////////////////////////////////////////////////////////////////
5276 // debug support
5277
5278 bool os::find(address addr, outputStream* st) {
5279 Dl_info dlinfo;
5280 memset(&dlinfo, 0, sizeof(dlinfo));
5281 if (dladdr(addr, &dlinfo) != 0) {
5282 st->print(PTR_FORMAT ": ", p2i(addr));
5283 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5284 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5285 p2i(addr) - p2i(dlinfo.dli_saddr));
5286 } else if (dlinfo.dli_fbase != NULL) {
5287 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5288 } else {
5289 st->print("<absolute address>");
5290 }
5291 if (dlinfo.dli_fname != NULL) {
5292 st->print(" in %s", dlinfo.dli_fname);
5293 }
5294 if (dlinfo.dli_fbase != NULL) {
5295 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5296 }
5297 st->cr();
5298
5299 if (Verbose) {
5300 // decode some bytes around the PC
5301 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5302 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5303 address lowest = (address) dlinfo.dli_sname;
5304 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5305 if (begin < lowest) begin = lowest;
5306 Dl_info dlinfo2;
5307 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5308 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5309 end = (address) dlinfo2.dli_saddr;
5310 }
5311 Disassembler::decode(begin, end, st);
5312 }
5313 return true;
5314 }
5315 return false;
5316 }
5317
5318 ////////////////////////////////////////////////////////////////////////////////
5319 // misc
5320
5321 // This does not do anything on Linux. This is basically a hook for being
5322 // able to use structured exception handling (thread-local exception filters)
5323 // on, e.g., Win32.
5324 void
5325 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5326 JavaCallArguments* args, Thread* thread) {
5327 f(value, method, args, thread);
5328 }
5329
5330 void os::print_statistics() {
5331 }
5332
5333 bool os::message_box(const char* title, const char* message) {
5334 int i;
5335 fdStream err(defaultStream::error_fd());
5336 for (i = 0; i < 78; i++) err.print_raw("=");
5337 err.cr();
5338 err.print_raw_cr(title);
5339 for (i = 0; i < 78; i++) err.print_raw("-");
5340 err.cr();
5341 err.print_raw_cr(message);
5342 for (i = 0; i < 78; i++) err.print_raw("=");
5343 err.cr();
5344
5345 char buf[16];
5346 // Prevent process from exiting upon "read error" without consuming all CPU
5347 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5348
5349 return buf[0] == 'y' || buf[0] == 'Y';
5350 }
5351
5352 int os::stat(const char *path, struct stat *sbuf) {
5353 char pathbuf[MAX_PATH];
5354 if (strlen(path) > MAX_PATH - 1) {
5355 errno = ENAMETOOLONG;
5356 return -1;
5357 }
5358 os::native_path(strcpy(pathbuf, path));
5359 return ::stat(pathbuf, sbuf);
5360 }
5361
5362 // Is a (classpath) directory empty?
5363 bool os::dir_is_empty(const char* path) {
5364 DIR *dir = NULL;
5365 struct dirent *ptr;
5366
5367 dir = opendir(path);
5368 if (dir == NULL) return true;
5369
5370 // Scan the directory
5371 bool result = true;
5372 char buf[sizeof(struct dirent) + MAX_PATH];
5373 while (result && (ptr = ::readdir(dir)) != NULL) {
5374 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5375 result = false;
5376 }
5377 }
5378 closedir(dir);
5379 return result;
5380 }
5381
5382 // This code originates from JDK's sysOpen and open64_w
5383 // from src/solaris/hpi/src/system_md.c
5384
5385 int os::open(const char *path, int oflag, int mode) {
5386 if (strlen(path) > MAX_PATH - 1) {
5387 errno = ENAMETOOLONG;
5388 return -1;
5389 }
5390
5391 // All file descriptors that are opened in the Java process and not
5392 // specifically destined for a subprocess should have the close-on-exec
5393 // flag set. If we don't set it, then careless 3rd party native code
5394 // might fork and exec without closing all appropriate file descriptors
5395 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5396 // turn might:
5397 //
5398 // - cause end-of-file to fail to be detected on some file
5399 // descriptors, resulting in mysterious hangs, or
5400 //
5401 // - might cause an fopen in the subprocess to fail on a system
5402 // suffering from bug 1085341.
5403 //
5404 // (Yes, the default setting of the close-on-exec flag is a Unix
5405 // design flaw)
5406 //
5407 // See:
5408 // 1085341: 32-bit stdio routines should support file descriptors >255
5409 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5410 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5411 //
5412 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5413 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5414 // because it saves a system call and removes a small window where the flag
5415 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5416 // and we fall back to using FD_CLOEXEC (see below).
5417 #ifdef O_CLOEXEC
5418 oflag |= O_CLOEXEC;
5419 #endif
5420
5421 int fd = ::open64(path, oflag, mode);
5422 if (fd == -1) return -1;
5423
5424 //If the open succeeded, the file might still be a directory
5425 {
5426 struct stat64 buf64;
5427 int ret = ::fstat64(fd, &buf64);
5428 int st_mode = buf64.st_mode;
5429
5430 if (ret != -1) {
5431 if ((st_mode & S_IFMT) == S_IFDIR) {
5432 errno = EISDIR;
5433 ::close(fd);
5434 return -1;
5435 }
5436 } else {
5437 ::close(fd);
5438 return -1;
5439 }
5440 }
5441
5442 #ifdef FD_CLOEXEC
5443 // Validate that the use of the O_CLOEXEC flag on open above worked.
5444 // With recent kernels, we will perform this check exactly once.
5445 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5446 if (!O_CLOEXEC_is_known_to_work) {
5447 int flags = ::fcntl(fd, F_GETFD);
5448 if (flags != -1) {
5449 if ((flags & FD_CLOEXEC) != 0)
5450 O_CLOEXEC_is_known_to_work = 1;
5451 else
5452 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5453 }
5454 }
5455 #endif
5456
5457 return fd;
5458 }
5459
5460
5461 // create binary file, rewriting existing file if required
5462 int os::create_binary_file(const char* path, bool rewrite_existing) {
5463 int oflags = O_WRONLY | O_CREAT;
5464 if (!rewrite_existing) {
5465 oflags |= O_EXCL;
5466 }
5467 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5468 }
5469
5470 // return current position of file pointer
5471 jlong os::current_file_offset(int fd) {
5472 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5473 }
5474
5475 // move file pointer to the specified offset
5476 jlong os::seek_to_file_offset(int fd, jlong offset) {
5477 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5478 }
5479
5480 // This code originates from JDK's sysAvailable
5481 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5482
5483 int os::available(int fd, jlong *bytes) {
5484 jlong cur, end;
5485 int mode;
5486 struct stat64 buf64;
5487
5488 if (::fstat64(fd, &buf64) >= 0) {
5489 mode = buf64.st_mode;
5490 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5491 int n;
5492 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5493 *bytes = n;
5494 return 1;
5495 }
5496 }
5497 }
5498 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5499 return 0;
5500 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5501 return 0;
5502 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5503 return 0;
5504 }
5505 *bytes = end - cur;
5506 return 1;
5507 }
5508
5509 // Map a block of memory.
5510 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5511 char *addr, size_t bytes, bool read_only,
5512 bool allow_exec) {
5513 int prot;
5514 int flags = MAP_PRIVATE;
5515
5516 if (read_only) {
5517 prot = PROT_READ;
5518 } else {
5519 prot = PROT_READ | PROT_WRITE;
5520 }
5521
5522 if (allow_exec) {
5523 prot |= PROT_EXEC;
5524 }
5525
5526 if (addr != NULL) {
5527 flags |= MAP_FIXED;
5528 }
5529
5530 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5531 fd, file_offset);
5532 if (mapped_address == MAP_FAILED) {
5533 return NULL;
5534 }
5535 return mapped_address;
5536 }
5537
5538
5539 // Remap a block of memory.
5540 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5541 char *addr, size_t bytes, bool read_only,
5542 bool allow_exec) {
5543 // same as map_memory() on this OS
5544 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5545 allow_exec);
5546 }
5547
5548
5549 // Unmap a block of memory.
5550 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5551 return munmap(addr, bytes) == 0;
5552 }
5553
5554 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5555
5556 static clockid_t thread_cpu_clockid(Thread* thread) {
5557 pthread_t tid = thread->osthread()->pthread_id();
5558 clockid_t clockid;
5559
5560 // Get thread clockid
5561 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5562 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5563 return clockid;
5564 }
5565
5566 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5567 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5568 // of a thread.
5569 //
5570 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5571 // the fast estimate available on the platform.
5572
5573 jlong os::current_thread_cpu_time() {
5574 if (os::Linux::supports_fast_thread_cpu_time()) {
5575 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5576 } else {
5577 // return user + sys since the cost is the same
5578 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5579 }
5580 }
5581
5582 jlong os::thread_cpu_time(Thread* thread) {
5583 // consistent with what current_thread_cpu_time() returns
5584 if (os::Linux::supports_fast_thread_cpu_time()) {
5585 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5586 } else {
5587 return slow_thread_cpu_time(thread, true /* user + sys */);
5588 }
5589 }
5590
5591 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5592 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5593 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5594 } else {
5595 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5596 }
5597 }
5598
5599 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5600 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5601 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5602 } else {
5603 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5604 }
5605 }
5606
5607 // -1 on error.
5608 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5609 pid_t tid = thread->osthread()->thread_id();
5610 char *s;
5611 char stat[2048];
5612 int statlen;
5613 char proc_name[64];
5614 int count;
5615 long sys_time, user_time;
5616 char cdummy;
5617 int idummy;
5618 long ldummy;
5619 FILE *fp;
5620
5621 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5622 fp = fopen(proc_name, "r");
5623 if (fp == NULL) return -1;
5624 statlen = fread(stat, 1, 2047, fp);
5625 stat[statlen] = '\0';
5626 fclose(fp);
5627
5628 // Skip pid and the command string. Note that we could be dealing with
5629 // weird command names, e.g. user could decide to rename java launcher
5630 // to "java 1.4.2 :)", then the stat file would look like
5631 // 1234 (java 1.4.2 :)) R ... ...
5632 // We don't really need to know the command string, just find the last
5633 // occurrence of ")" and then start parsing from there. See bug 4726580.
5634 s = strrchr(stat, ')');
5635 if (s == NULL) return -1;
5636
5637 // Skip blank chars
5638 do { s++; } while (s && isspace(*s));
5639
5640 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5641 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5642 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5643 &user_time, &sys_time);
5644 if (count != 13) return -1;
5645 if (user_sys_cpu_time) {
5646 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5647 } else {
5648 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5649 }
5650 }
5651
5652 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5653 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5654 info_ptr->may_skip_backward = false; // elapsed time not wall time
5655 info_ptr->may_skip_forward = false; // elapsed time not wall time
5656 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5657 }
5658
5659 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5660 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5661 info_ptr->may_skip_backward = false; // elapsed time not wall time
5662 info_ptr->may_skip_forward = false; // elapsed time not wall time
5663 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5664 }
5665
5666 bool os::is_thread_cpu_time_supported() {
5667 return true;
5668 }
5669
5670 // System loadavg support. Returns -1 if load average cannot be obtained.
5671 // Linux doesn't yet have a (official) notion of processor sets,
5672 // so just return the system wide load average.
5673 int os::loadavg(double loadavg[], int nelem) {
5674 return ::getloadavg(loadavg, nelem);
5675 }
5676
5677 void os::pause() {
5678 char filename[MAX_PATH];
5679 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5680 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5681 } else {
5682 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5683 }
5684
5685 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5686 if (fd != -1) {
5687 struct stat buf;
5688 ::close(fd);
5689 while (::stat(filename, &buf) == 0) {
5690 (void)::poll(NULL, 0, 100);
5691 }
5692 } else {
5693 jio_fprintf(stderr,
5694 "Could not open pause file '%s', continuing immediately.\n", filename);
5695 }
5696 }
5697
5698 extern char** environ;
5699
5700 // Run the specified command in a separate process. Return its exit value,
5701 // or -1 on failure (e.g. can't fork a new process).
5702 // Unlike system(), this function can be called from signal handler. It
5703 // doesn't block SIGINT et al.
5704 int os::fork_and_exec(char* cmd) {
5705 const char * argv[4] = {"sh", "-c", cmd, NULL};
5706
5707 pid_t pid = fork();
5708
5709 if (pid < 0) {
5710 // fork failed
5711 return -1;
5712
5713 } else if (pid == 0) {
5714 // child process
5715
5716 execve("/bin/sh", (char* const*)argv, environ);
5717
5718 // execve failed
5719 _exit(-1);
5720
5721 } else {
5722 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5723 // care about the actual exit code, for now.
5724
5725 int status;
5726
5727 // Wait for the child process to exit. This returns immediately if
5728 // the child has already exited. */
5729 while (waitpid(pid, &status, 0) < 0) {
5730 switch (errno) {
5731 case ECHILD: return 0;
5732 case EINTR: break;
5733 default: return -1;
5734 }
5735 }
5736
5737 if (WIFEXITED(status)) {
5738 // The child exited normally; get its exit code.
5739 return WEXITSTATUS(status);
5740 } else if (WIFSIGNALED(status)) {
5741 // The child exited because of a signal
5742 // The best value to return is 0x80 + signal number,
5743 // because that is what all Unix shells do, and because
5744 // it allows callers to distinguish between process exit and
5745 // process death by signal.
5746 return 0x80 + WTERMSIG(status);
5747 } else {
5748 // Unknown exit code; pass it through
5749 return status;
5750 }
5751 }
5752 }
5753
5754 // Get the default path to the core file
5755 // Returns the length of the string
5756 int os::get_core_path(char* buffer, size_t bufferSize) {
5757 /*
5758 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5759 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5760 */
5761 const int core_pattern_len = 129;
5762 char core_pattern[core_pattern_len] = {0};
5763
5764 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5765 if (core_pattern_file == -1) {
5766 return -1;
5767 }
5768
5769 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5770 ::close(core_pattern_file);
5771 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5772 return -1;
5773 }
5774 if (core_pattern[ret-1] == '\n') {
5775 core_pattern[ret-1] = '\0';
5776 } else {
5777 core_pattern[ret] = '\0';
5778 }
5779
5780 char *pid_pos = strstr(core_pattern, "%p");
5781 int written;
5782
5783 if (core_pattern[0] == '/') {
5784 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5785 } else {
5786 char cwd[PATH_MAX];
5787
5788 const char* p = get_current_directory(cwd, PATH_MAX);
5789 if (p == NULL) {
5790 return -1;
5791 }
5792
5793 if (core_pattern[0] == '|') {
5794 written = jio_snprintf(buffer, bufferSize,
5795 "\"%s\" (or dumping to %s/core.%d)",
5796 &core_pattern[1], p, current_process_id());
5797 } else {
5798 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5799 }
5800 }
5801
5802 if (written < 0) {
5803 return -1;
5804 }
5805
5806 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5807 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5808
5809 if (core_uses_pid_file != -1) {
5810 char core_uses_pid = 0;
5811 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5812 ::close(core_uses_pid_file);
5813
5814 if (core_uses_pid == '1') {
5815 jio_snprintf(buffer + written, bufferSize - written,
5816 ".%d", current_process_id());
5817 }
5818 }
5819 }
5820
5821 return strlen(buffer);
5822 }
5823
5824 bool os::start_debugging(char *buf, int buflen) {
5825 int len = (int)strlen(buf);
5826 char *p = &buf[len];
5827
5828 jio_snprintf(p, buflen-len,
5829 "\n\n"
5830 "Do you want to debug the problem?\n\n"
5831 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
5832 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
5833 "Otherwise, press RETURN to abort...",
5834 os::current_process_id(), os::current_process_id(),
5835 os::current_thread_id(), os::current_thread_id());
5836
5837 bool yes = os::message_box("Unexpected Error", buf);
5838
5839 if (yes) {
5840 // yes, user asked VM to launch debugger
5841 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
5842 os::current_process_id(), os::current_process_id());
5843
5844 os::fork_and_exec(buf);
5845 yes = false;
5846 }
5847 return yes;
5848 }
5849
5850
5851 // Java/Compiler thread:
5852 //
5853 // Low memory addresses
5854 // P0 +------------------------+
5855 // | |\ Java thread created by VM does not have glibc
5856 // | glibc guard page | - guard page, attached Java thread usually has
5857 // | |/ 1 glibc guard page.
5858 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5859 // | |\
5860 // | HotSpot Guard Pages | - red, yellow and reserved pages
5861 // | |/
5862 // +------------------------+ JavaThread::stack_reserved_zone_base()
5863 // | |\
5864 // | Normal Stack | -
5865 // | |/
5866 // P2 +------------------------+ Thread::stack_base()
5867 //
5868 // Non-Java thread:
5869 //
5870 // Low memory addresses
5871 // P0 +------------------------+
5872 // | |\
5873 // | glibc guard page | - usually 1 page
5874 // | |/
5875 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5876 // | |\
5877 // | Normal Stack | -
5878 // | |/
5879 // P2 +------------------------+ Thread::stack_base()
5880 //
5881 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
5882 // returned from pthread_attr_getstack().
5883 // ** Due to NPTL implementation error, linux takes the glibc guard page out
5884 // of the stack size given in pthread_attr. We work around this for
5885 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
5886 //
5887 #ifndef ZERO
5888 static void current_stack_region(address * bottom, size_t * size) {
5889 if (os::is_primordial_thread()) {
5890 // primordial thread needs special handling because pthread_getattr_np()
5891 // may return bogus value.
5892 *bottom = os::Linux::initial_thread_stack_bottom();
5893 *size = os::Linux::initial_thread_stack_size();
5894 } else {
5895 pthread_attr_t attr;
5896
5897 int rslt = pthread_getattr_np(pthread_self(), &attr);
5898
5899 // JVM needs to know exact stack location, abort if it fails
5900 if (rslt != 0) {
5901 if (rslt == ENOMEM) {
5902 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
5903 } else {
5904 fatal("pthread_getattr_np failed with error = %d", rslt);
5905 }
5906 }
5907
5908 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
5909 fatal("Cannot locate current stack attributes!");
5910 }
5911
5912 // Work around NPTL stack guard error.
5913 size_t guard_size = 0;
5914 rslt = pthread_attr_getguardsize(&attr, &guard_size);
5915 if (rslt != 0) {
5916 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
5917 }
5918 *bottom += guard_size;
5919 *size -= guard_size;
5920
5921 pthread_attr_destroy(&attr);
5922
5923 }
5924 assert(os::current_stack_pointer() >= *bottom &&
5925 os::current_stack_pointer() < *bottom + *size, "just checking");
5926 }
5927
5928 address os::current_stack_base() {
5929 address bottom;
5930 size_t size;
5931 current_stack_region(&bottom, &size);
5932 return (bottom + size);
5933 }
5934
5935 size_t os::current_stack_size() {
5936 // This stack size includes the usable stack and HotSpot guard pages
5937 // (for the threads that have Hotspot guard pages).
5938 address bottom;
5939 size_t size;
5940 current_stack_region(&bottom, &size);
5941 return size;
5942 }
5943 #endif
5944
5945 static inline struct timespec get_mtime(const char* filename) {
5946 struct stat st;
5947 int ret = os::stat(filename, &st);
5948 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
5949 return st.st_mtim;
5950 }
5951
5952 int os::compare_file_modified_times(const char* file1, const char* file2) {
5953 struct timespec filetime1 = get_mtime(file1);
5954 struct timespec filetime2 = get_mtime(file2);
5955 int diff = filetime1.tv_sec - filetime2.tv_sec;
5956 if (diff == 0) {
5957 return filetime1.tv_nsec - filetime2.tv_nsec;
5958 }
5959 return diff;
5960 }
5961
5962 /////////////// Unit tests ///////////////
5963
5964 #ifndef PRODUCT
5965
5966 #define test_log(...) \
5967 do { \
5968 if (VerboseInternalVMTests) { \
5969 tty->print_cr(__VA_ARGS__); \
5970 tty->flush(); \
5971 } \
5972 } while (false)
5973
5974 class TestReserveMemorySpecial : AllStatic {
5975 public:
5976 static void small_page_write(void* addr, size_t size) {
5977 size_t page_size = os::vm_page_size();
5978
5979 char* end = (char*)addr + size;
5980 for (char* p = (char*)addr; p < end; p += page_size) {
5981 *p = 1;
5982 }
5983 }
5984
5985 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
5986 if (!UseHugeTLBFS) {
5987 return;
5988 }
5989
5990 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
5991
5992 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
5993
5994 if (addr != NULL) {
5995 small_page_write(addr, size);
5996
5997 os::Linux::release_memory_special_huge_tlbfs(addr, size);
5998 }
5999 }
6000
6001 static void test_reserve_memory_special_huge_tlbfs_only() {
6002 if (!UseHugeTLBFS) {
6003 return;
6004 }
6005
6006 size_t lp = os::large_page_size();
6007
6008 for (size_t size = lp; size <= lp * 10; size += lp) {
6009 test_reserve_memory_special_huge_tlbfs_only(size);
6010 }
6011 }
6012
6013 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6014 size_t lp = os::large_page_size();
6015 size_t ag = os::vm_allocation_granularity();
6016
6017 // sizes to test
6018 const size_t sizes[] = {
6019 lp, lp + ag, lp + lp / 2, lp * 2,
6020 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6021 lp * 10, lp * 10 + lp / 2
6022 };
6023 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6024
6025 // For each size/alignment combination, we test three scenarios:
6026 // 1) with req_addr == NULL
6027 // 2) with a non-null req_addr at which we expect to successfully allocate
6028 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6029 // expect the allocation to either fail or to ignore req_addr
6030
6031 // Pre-allocate two areas; they shall be as large as the largest allocation
6032 // and aligned to the largest alignment we will be testing.
6033 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6034 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6035 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6036 -1, 0);
6037 assert(mapping1 != MAP_FAILED, "should work");
6038
6039 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6040 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6041 -1, 0);
6042 assert(mapping2 != MAP_FAILED, "should work");
6043
6044 // Unmap the first mapping, but leave the second mapping intact: the first
6045 // mapping will serve as a value for a "good" req_addr (case 2). The second
6046 // mapping, still intact, as "bad" req_addr (case 3).
6047 ::munmap(mapping1, mapping_size);
6048
6049 // Case 1
6050 test_log("%s, req_addr NULL:", __FUNCTION__);
6051 test_log("size align result");
6052
6053 for (int i = 0; i < num_sizes; i++) {
6054 const size_t size = sizes[i];
6055 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6056 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6057 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6058 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6059 if (p != NULL) {
6060 assert(is_aligned(p, alignment), "must be");
6061 small_page_write(p, size);
6062 os::Linux::release_memory_special_huge_tlbfs(p, size);
6063 }
6064 }
6065 }
6066
6067 // Case 2
6068 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6069 test_log("size align req_addr result");
6070
6071 for (int i = 0; i < num_sizes; i++) {
6072 const size_t size = sizes[i];
6073 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6074 char* const req_addr = align_up(mapping1, alignment);
6075 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6076 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6077 size, alignment, p2i(req_addr), p2i(p),
6078 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6079 if (p != NULL) {
6080 assert(p == req_addr, "must be");
6081 small_page_write(p, size);
6082 os::Linux::release_memory_special_huge_tlbfs(p, size);
6083 }
6084 }
6085 }
6086
6087 // Case 3
6088 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6089 test_log("size align req_addr result");
6090
6091 for (int i = 0; i < num_sizes; i++) {
6092 const size_t size = sizes[i];
6093 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6094 char* const req_addr = align_up(mapping2, alignment);
6095 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6096 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6097 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6098 // as the area around req_addr contains already existing mappings, the API should always
6099 // return NULL (as per contract, it cannot return another address)
6100 assert(p == NULL, "must be");
6101 }
6102 }
6103
6104 ::munmap(mapping2, mapping_size);
6105
6106 }
6107
6108 static void test_reserve_memory_special_huge_tlbfs() {
6109 if (!UseHugeTLBFS) {
6110 return;
6111 }
6112
6113 test_reserve_memory_special_huge_tlbfs_only();
6114 test_reserve_memory_special_huge_tlbfs_mixed();
6115 }
6116
6117 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6118 if (!UseSHM) {
6119 return;
6120 }
6121
6122 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6123
6124 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6125
6126 if (addr != NULL) {
6127 assert(is_aligned(addr, alignment), "Check");
6128 assert(is_aligned(addr, os::large_page_size()), "Check");
6129
6130 small_page_write(addr, size);
6131
6132 os::Linux::release_memory_special_shm(addr, size);
6133 }
6134 }
6135
6136 static void test_reserve_memory_special_shm() {
6137 size_t lp = os::large_page_size();
6138 size_t ag = os::vm_allocation_granularity();
6139
6140 for (size_t size = ag; size < lp * 3; size += ag) {
6141 for (size_t alignment = ag; is_aligned(size, alignment); alignment *= 2) {
6142 test_reserve_memory_special_shm(size, alignment);
6143 }
6144 }
6145 }
6146
6147 static void test() {
6148 test_reserve_memory_special_huge_tlbfs();
6149 test_reserve_memory_special_shm();
6150 }
6151 };
6152
6153 void TestReserveMemorySpecial_test() {
6154 TestReserveMemorySpecial::test();
6155 }
6156
6157 #endif