1 /*
2 * Copyright (c) 1999, 2017, 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 "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
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 "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
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.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/timer.hpp"
63 #include "semaphore_posix.hpp"
64 #include "services/attachListener.hpp"
65 #include "services/memTracker.hpp"
66 #include "services/runtimeService.hpp"
67 #include "utilities/decoder.hpp"
68 #include "utilities/defaultStream.hpp"
69 #include "utilities/events.hpp"
70 #include "utilities/elfFile.hpp"
71 #include "utilities/growableArray.hpp"
72 #include "utilities/macros.hpp"
73 #include "utilities/vmError.hpp"
74
75 // put OS-includes here
76 # include <sys/types.h>
77 # include <sys/mman.h>
78 # include <sys/stat.h>
79 # include <sys/select.h>
80 # include <pthread.h>
81 # include <signal.h>
82 # include <errno.h>
83 # include <dlfcn.h>
84 # include <stdio.h>
85 # include <unistd.h>
86 # include <sys/resource.h>
87 # include <pthread.h>
88 # include <sys/stat.h>
89 # include <sys/time.h>
90 # include <sys/times.h>
91 # include <sys/utsname.h>
92 # include <sys/socket.h>
93 # include <sys/wait.h>
94 # include <pwd.h>
95 # include <poll.h>
96 # include <semaphore.h>
97 # include <fcntl.h>
98 # include <string.h>
99 # include <syscall.h>
100 # include <sys/sysinfo.h>
101 # include <gnu/libc-version.h>
102 # include <sys/ipc.h>
103 # include <sys/shm.h>
104 # include <link.h>
105 # include <stdint.h>
106 # include <inttypes.h>
107 # include <sys/ioctl.h>
108
109 #ifndef _GNU_SOURCE
110 #define _GNU_SOURCE
111 #include <sched.h>
112 #undef _GNU_SOURCE
113 #else
114 #include <sched.h>
115 #endif
116
117 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
118 // getrusage() is prepared to handle the associated failure.
119 #ifndef RUSAGE_THREAD
120 #define RUSAGE_THREAD (1) /* only the calling thread */
121 #endif
122
123 #define MAX_PATH (2 * K)
124
125 #define MAX_SECS 100000000
126
127 // for timer info max values which include all bits
128 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
129
130 #define LARGEPAGES_BIT (1 << 6)
131 ////////////////////////////////////////////////////////////////////////////////
132 // global variables
133 julong os::Linux::_physical_memory = 0;
134
135 address os::Linux::_initial_thread_stack_bottom = NULL;
136 uintptr_t os::Linux::_initial_thread_stack_size = 0;
137
138 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
139 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
140 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
141 Mutex* os::Linux::_createThread_lock = NULL;
142 pthread_t os::Linux::_main_thread;
143 int os::Linux::_page_size = -1;
144 bool os::Linux::_supports_fast_thread_cpu_time = false;
145 uint32_t os::Linux::_os_version = 0;
146 const char * os::Linux::_glibc_version = NULL;
147 const char * os::Linux::_libpthread_version = NULL;
148
149 static jlong initial_time_count=0;
150
151 static int clock_tics_per_sec = 100;
152
153 // For diagnostics to print a message once. see run_periodic_checks
154 static sigset_t check_signal_done;
155 static bool check_signals = true;
156
157 // Signal number used to suspend/resume a thread
158
159 // do not use any signal number less than SIGSEGV, see 4355769
160 static int SR_signum = SIGUSR2;
161 sigset_t SR_sigset;
162
163 // utility functions
164
165 static int SR_initialize();
166
167 julong os::available_memory() {
168 return Linux::available_memory();
169 }
170
171 julong os::Linux::available_memory() {
172 // values in struct sysinfo are "unsigned long"
173 struct sysinfo si;
174 sysinfo(&si);
175
176 return (julong)si.freeram * si.mem_unit;
177 }
178
179 julong os::physical_memory() {
180 return Linux::physical_memory();
181 }
182
183 // Return true if user is running as root.
184
185 bool os::have_special_privileges() {
186 static bool init = false;
187 static bool privileges = false;
188 if (!init) {
189 privileges = (getuid() != geteuid()) || (getgid() != getegid());
190 init = true;
191 }
192 return privileges;
193 }
194
195
196 #ifndef SYS_gettid
197 // i386: 224, ia64: 1105, amd64: 186, sparc 143
198 #ifdef __ia64__
199 #define SYS_gettid 1105
200 #else
201 #ifdef __i386__
202 #define SYS_gettid 224
203 #else
204 #ifdef __amd64__
205 #define SYS_gettid 186
206 #else
207 #ifdef __sparc__
208 #define SYS_gettid 143
209 #else
210 #error define gettid for the arch
211 #endif
212 #endif
213 #endif
214 #endif
215 #endif
216
217
218 // pid_t gettid()
219 //
220 // Returns the kernel thread id of the currently running thread. Kernel
221 // thread id is used to access /proc.
222 pid_t os::Linux::gettid() {
223 int rslt = syscall(SYS_gettid);
224 assert(rslt != -1, "must be."); // old linuxthreads implementation?
225 return (pid_t)rslt;
226 }
227
228 // Most versions of linux have a bug where the number of processors are
229 // determined by looking at the /proc file system. In a chroot environment,
230 // the system call returns 1. This causes the VM to act as if it is
231 // a single processor and elide locking (see is_MP() call).
232 static bool unsafe_chroot_detected = false;
233 static const char *unstable_chroot_error = "/proc file system not found.\n"
234 "Java may be unstable running multithreaded in a chroot "
235 "environment on Linux when /proc filesystem is not mounted.";
236
237 void os::Linux::initialize_system_info() {
238 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
239 if (processor_count() == 1) {
240 pid_t pid = os::Linux::gettid();
241 char fname[32];
242 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
243 FILE *fp = fopen(fname, "r");
244 if (fp == NULL) {
245 unsafe_chroot_detected = true;
246 } else {
247 fclose(fp);
248 }
249 }
250 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
251 assert(processor_count() > 0, "linux error");
252 }
253
254 void os::init_system_properties_values() {
255 // The next steps are taken in the product version:
256 //
257 // Obtain the JAVA_HOME value from the location of libjvm.so.
258 // This library should be located at:
259 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
260 //
261 // If "/jre/lib/" appears at the right place in the path, then we
262 // assume libjvm.so is installed in a JDK and we use this path.
263 //
264 // Otherwise exit with message: "Could not create the Java virtual machine."
265 //
266 // The following extra steps are taken in the debugging version:
267 //
268 // If "/jre/lib/" does NOT appear at the right place in the path
269 // instead of exit check for $JAVA_HOME environment variable.
270 //
271 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
272 // then we append a fake suffix "hotspot/libjvm.so" to this path so
273 // it looks like libjvm.so is installed there
274 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
275 //
276 // Otherwise exit.
277 //
278 // Important note: if the location of libjvm.so changes this
279 // code needs to be changed accordingly.
280
281 // See ld(1):
282 // The linker uses the following search paths to locate required
283 // shared libraries:
284 // 1: ...
285 // ...
286 // 7: The default directories, normally /lib and /usr/lib.
287 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
288 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
289 #else
290 #define DEFAULT_LIBPATH "/lib:/usr/lib"
291 #endif
292
293 // Base path of extensions installed on the system.
294 #define SYS_EXT_DIR "/usr/java/packages"
295 #define EXTENSIONS_DIR "/lib/ext"
296
297 // Buffer that fits several sprintfs.
298 // Note that the space for the colon and the trailing null are provided
299 // by the nulls included by the sizeof operator.
300 const size_t bufsize =
301 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
302 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
303 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
304
305 // sysclasspath, java_home, dll_dir
306 {
307 char *pslash;
308 os::jvm_path(buf, bufsize);
309
310 // Found the full path to libjvm.so.
311 // Now cut the path to <java_home>/jre if we can.
312 pslash = strrchr(buf, '/');
313 if (pslash != NULL) {
314 *pslash = '\0'; // Get rid of /libjvm.so.
315 }
316 pslash = strrchr(buf, '/');
317 if (pslash != NULL) {
318 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
319 }
320 Arguments::set_dll_dir(buf);
321
322 if (pslash != NULL) {
323 pslash = strrchr(buf, '/');
324 if (pslash != NULL) {
325 *pslash = '\0'; // Get rid of /lib.
326 }
327 }
328 Arguments::set_java_home(buf);
329 set_boot_path('/', ':');
330 }
331
332 // Where to look for native libraries.
333 //
334 // Note: Due to a legacy implementation, most of the library path
335 // is set in the launcher. This was to accomodate linking restrictions
336 // on legacy Linux implementations (which are no longer supported).
337 // Eventually, all the library path setting will be done here.
338 //
339 // However, to prevent the proliferation of improperly built native
340 // libraries, the new path component /usr/java/packages is added here.
341 // Eventually, all the library path setting will be done here.
342 {
343 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
344 // should always exist (until the legacy problem cited above is
345 // addressed).
346 const char *v = ::getenv("LD_LIBRARY_PATH");
347 const char *v_colon = ":";
348 if (v == NULL) { v = ""; v_colon = ""; }
349 // That's +1 for the colon and +1 for the trailing '\0'.
350 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
351 strlen(v) + 1 +
352 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
353 mtInternal);
354 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
355 Arguments::set_library_path(ld_library_path);
356 FREE_C_HEAP_ARRAY(char, ld_library_path);
357 }
358
359 // Extensions directories.
360 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
361 Arguments::set_ext_dirs(buf);
362
363 FREE_C_HEAP_ARRAY(char, buf);
364
365 #undef DEFAULT_LIBPATH
366 #undef SYS_EXT_DIR
367 #undef EXTENSIONS_DIR
368 }
369
370 ////////////////////////////////////////////////////////////////////////////////
371 // breakpoint support
372
373 void os::breakpoint() {
374 BREAKPOINT;
375 }
376
377 extern "C" void breakpoint() {
378 // use debugger to set breakpoint here
379 }
380
381 ////////////////////////////////////////////////////////////////////////////////
382 // signal support
383
384 debug_only(static bool signal_sets_initialized = false);
385 static sigset_t unblocked_sigs, vm_sigs;
386
387 bool os::Linux::is_sig_ignored(int sig) {
388 struct sigaction oact;
389 sigaction(sig, (struct sigaction*)NULL, &oact);
390 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
391 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
392 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
393 return true;
394 } else {
395 return false;
396 }
397 }
398
399 void os::Linux::signal_sets_init() {
400 // Should also have an assertion stating we are still single-threaded.
401 assert(!signal_sets_initialized, "Already initialized");
402 // Fill in signals that are necessarily unblocked for all threads in
403 // the VM. Currently, we unblock the following signals:
404 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
405 // by -Xrs (=ReduceSignalUsage));
406 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
407 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
408 // the dispositions or masks wrt these signals.
409 // Programs embedding the VM that want to use the above signals for their
410 // own purposes must, at this time, use the "-Xrs" option to prevent
411 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
412 // (See bug 4345157, and other related bugs).
413 // In reality, though, unblocking these signals is really a nop, since
414 // these signals are not blocked by default.
415 sigemptyset(&unblocked_sigs);
416 sigaddset(&unblocked_sigs, SIGILL);
417 sigaddset(&unblocked_sigs, SIGSEGV);
418 sigaddset(&unblocked_sigs, SIGBUS);
419 sigaddset(&unblocked_sigs, SIGFPE);
420 #if defined(PPC64)
421 sigaddset(&unblocked_sigs, SIGTRAP);
422 #endif
423 sigaddset(&unblocked_sigs, SR_signum);
424
425 if (!ReduceSignalUsage) {
426 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
427 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
428 }
429 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
430 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
431 }
432 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
433 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
434 }
435 }
436 // Fill in signals that are blocked by all but the VM thread.
437 sigemptyset(&vm_sigs);
438 if (!ReduceSignalUsage) {
439 sigaddset(&vm_sigs, BREAK_SIGNAL);
440 }
441 debug_only(signal_sets_initialized = true);
442
443 }
444
445 // These are signals that are unblocked while a thread is running Java.
446 // (For some reason, they get blocked by default.)
447 sigset_t* os::Linux::unblocked_signals() {
448 assert(signal_sets_initialized, "Not initialized");
449 return &unblocked_sigs;
450 }
451
452 // These are the signals that are blocked while a (non-VM) thread is
453 // running Java. Only the VM thread handles these signals.
454 sigset_t* os::Linux::vm_signals() {
455 assert(signal_sets_initialized, "Not initialized");
456 return &vm_sigs;
457 }
458
459 void os::Linux::hotspot_sigmask(Thread* thread) {
460
461 //Save caller's signal mask before setting VM signal mask
462 sigset_t caller_sigmask;
463 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
464
465 OSThread* osthread = thread->osthread();
466 osthread->set_caller_sigmask(caller_sigmask);
467
468 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
469
470 if (!ReduceSignalUsage) {
471 if (thread->is_VM_thread()) {
472 // Only the VM thread handles BREAK_SIGNAL ...
473 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
474 } else {
475 // ... all other threads block BREAK_SIGNAL
476 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
477 }
478 }
479 }
480
481 //////////////////////////////////////////////////////////////////////////////
482 // detecting pthread library
483
484 void os::Linux::libpthread_init() {
485 // Save glibc and pthread version strings.
486 #if !defined(_CS_GNU_LIBC_VERSION) || \
487 !defined(_CS_GNU_LIBPTHREAD_VERSION)
488 #error "glibc too old (< 2.3.2)"
489 #endif
490
491 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
492 assert(n > 0, "cannot retrieve glibc version");
493 char *str = (char *)malloc(n, mtInternal);
494 confstr(_CS_GNU_LIBC_VERSION, str, n);
495 os::Linux::set_glibc_version(str);
496
497 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
498 assert(n > 0, "cannot retrieve pthread version");
499 str = (char *)malloc(n, mtInternal);
500 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
501 os::Linux::set_libpthread_version(str);
502 }
503
504 /////////////////////////////////////////////////////////////////////////////
505 // thread stack expansion
506
507 // os::Linux::manually_expand_stack() takes care of expanding the thread
508 // stack. Note that this is normally not needed: pthread stacks allocate
509 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
510 // committed. Therefore it is not necessary to expand the stack manually.
511 //
512 // Manually expanding the stack was historically needed on LinuxThreads
513 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
514 // it is kept to deal with very rare corner cases:
515 //
516 // For one, user may run the VM on an own implementation of threads
517 // whose stacks are - like the old LinuxThreads - implemented using
518 // mmap(MAP_GROWSDOWN).
519 //
520 // Also, this coding may be needed if the VM is running on the primordial
521 // thread. Normally we avoid running on the primordial thread; however,
522 // user may still invoke the VM on the primordial thread.
523 //
524 // The following historical comment describes the details about running
525 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
526
527
528 // Force Linux kernel to expand current thread stack. If "bottom" is close
529 // to the stack guard, caller should block all signals.
530 //
531 // MAP_GROWSDOWN:
532 // A special mmap() flag that is used to implement thread stacks. It tells
533 // kernel that the memory region should extend downwards when needed. This
534 // allows early versions of LinuxThreads to only mmap the first few pages
535 // when creating a new thread. Linux kernel will automatically expand thread
536 // stack as needed (on page faults).
537 //
538 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
539 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
540 // region, it's hard to tell if the fault is due to a legitimate stack
541 // access or because of reading/writing non-exist memory (e.g. buffer
542 // overrun). As a rule, if the fault happens below current stack pointer,
543 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
544 // application (see Linux kernel fault.c).
545 //
546 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
547 // stack overflow detection.
548 //
549 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
550 // not use MAP_GROWSDOWN.
551 //
552 // To get around the problem and allow stack banging on Linux, we need to
553 // manually expand thread stack after receiving the SIGSEGV.
554 //
555 // There are two ways to expand thread stack to address "bottom", we used
556 // both of them in JVM before 1.5:
557 // 1. adjust stack pointer first so that it is below "bottom", and then
558 // touch "bottom"
559 // 2. mmap() the page in question
560 //
561 // Now alternate signal stack is gone, it's harder to use 2. For instance,
562 // if current sp is already near the lower end of page 101, and we need to
563 // call mmap() to map page 100, it is possible that part of the mmap() frame
564 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
565 // That will destroy the mmap() frame and cause VM to crash.
566 //
567 // The following code works by adjusting sp first, then accessing the "bottom"
568 // page to force a page fault. Linux kernel will then automatically expand the
569 // stack mapping.
570 //
571 // _expand_stack_to() assumes its frame size is less than page size, which
572 // should always be true if the function is not inlined.
573
574 static void NOINLINE _expand_stack_to(address bottom) {
575 address sp;
576 size_t size;
577 volatile char *p;
578
579 // Adjust bottom to point to the largest address within the same page, it
580 // gives us a one-page buffer if alloca() allocates slightly more memory.
581 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
582 bottom += os::Linux::page_size() - 1;
583
584 // sp might be slightly above current stack pointer; if that's the case, we
585 // will alloca() a little more space than necessary, which is OK. Don't use
586 // os::current_stack_pointer(), as its result can be slightly below current
587 // stack pointer, causing us to not alloca enough to reach "bottom".
588 sp = (address)&sp;
589
590 if (sp > bottom) {
591 size = sp - bottom;
592 p = (volatile char *)alloca(size);
593 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
594 p[0] = '\0';
595 }
596 }
597
598 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
599 assert(t!=NULL, "just checking");
600 assert(t->osthread()->expanding_stack(), "expand should be set");
601 assert(t->stack_base() != NULL, "stack_base was not initialized");
602
603 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
604 sigset_t mask_all, old_sigset;
605 sigfillset(&mask_all);
606 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
607 _expand_stack_to(addr);
608 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
609 return true;
610 }
611 return false;
612 }
613
614 //////////////////////////////////////////////////////////////////////////////
615 // create new thread
616
617 // Thread start routine for all newly created threads
618 static void *thread_native_entry(Thread *thread) {
619 // Try to randomize the cache line index of hot stack frames.
620 // This helps when threads of the same stack traces evict each other's
621 // cache lines. The threads can be either from the same JVM instance, or
622 // from different JVM instances. The benefit is especially true for
623 // processors with hyperthreading technology.
624 static int counter = 0;
625 int pid = os::current_process_id();
626 alloca(((pid ^ counter++) & 7) * 128);
627
628 thread->initialize_thread_current();
629
630 OSThread* osthread = thread->osthread();
631 Monitor* sync = osthread->startThread_lock();
632
633 osthread->set_thread_id(os::current_thread_id());
634
635 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
636 os::current_thread_id(), (uintx) pthread_self());
637
638 if (UseNUMA) {
639 int lgrp_id = os::numa_get_group_id();
640 if (lgrp_id != -1) {
641 thread->set_lgrp_id(lgrp_id);
642 }
643 }
644 // initialize signal mask for this thread
645 os::Linux::hotspot_sigmask(thread);
646
647 // initialize floating point control register
648 os::Linux::init_thread_fpu_state();
649
650 // handshaking with parent thread
651 {
652 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
653
654 // notify parent thread
655 osthread->set_state(INITIALIZED);
656 sync->notify_all();
657
658 // wait until os::start_thread()
659 while (osthread->get_state() == INITIALIZED) {
660 sync->wait(Mutex::_no_safepoint_check_flag);
661 }
662 }
663
664 // call one more level start routine
665 thread->run();
666
667 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
668 os::current_thread_id(), (uintx) pthread_self());
669
670 // If a thread has not deleted itself ("delete this") as part of its
671 // termination sequence, we have to ensure thread-local-storage is
672 // cleared before we actually terminate. No threads should ever be
673 // deleted asynchronously with respect to their termination.
674 if (Thread::current_or_null_safe() != NULL) {
675 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
676 thread->clear_thread_current();
677 }
678
679 return 0;
680 }
681
682 bool os::create_thread(Thread* thread, ThreadType thr_type,
683 size_t req_stack_size) {
684 assert(thread->osthread() == NULL, "caller responsible");
685
686 // Allocate the OSThread object
687 OSThread* osthread = new OSThread(NULL, NULL);
688 if (osthread == NULL) {
689 return false;
690 }
691
692 // set the correct thread state
693 osthread->set_thread_type(thr_type);
694
695 // Initial state is ALLOCATED but not INITIALIZED
696 osthread->set_state(ALLOCATED);
697
698 thread->set_osthread(osthread);
699
700 // init thread attributes
701 pthread_attr_t attr;
702 pthread_attr_init(&attr);
703 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
704
705 // Calculate stack size if it's not specified by caller.
706 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
707 // In the Linux NPTL pthread implementation the guard size mechanism
708 // is not implemented properly. The posix standard requires adding
709 // the size of the guard pages to the stack size, instead Linux
710 // takes the space out of 'stacksize'. Thus we adapt the requested
711 // stack_size by the size of the guard pages to mimick proper
712 // behaviour. However, be careful not to end up with a size
713 // of zero due to overflow. Don't add the guard page in that case.
714 size_t guard_size = os::Linux::default_guard_size(thr_type);
715 if (stack_size <= SIZE_MAX - guard_size) {
716 stack_size += guard_size;
717 }
718 assert(is_size_aligned(stack_size, os::vm_page_size()), "stack_size not aligned");
719
720 int status = pthread_attr_setstacksize(&attr, stack_size);
721 assert_status(status == 0, status, "pthread_attr_setstacksize");
722
723 // Configure glibc guard page.
724 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
725
726 ThreadState state;
727
728 {
729 pthread_t tid;
730 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
731
732 char buf[64];
733 if (ret == 0) {
734 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
735 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
736 } else {
737 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
738 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
739 }
740
741 pthread_attr_destroy(&attr);
742
743 if (ret != 0) {
744 // Need to clean up stuff we've allocated so far
745 thread->set_osthread(NULL);
746 delete osthread;
747 return false;
748 }
749
750 // Store pthread info into the OSThread
751 osthread->set_pthread_id(tid);
752
753 // Wait until child thread is either initialized or aborted
754 {
755 Monitor* sync_with_child = osthread->startThread_lock();
756 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
757 while ((state = osthread->get_state()) == ALLOCATED) {
758 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
759 }
760 }
761 }
762
763 // Aborted due to thread limit being reached
764 if (state == ZOMBIE) {
765 thread->set_osthread(NULL);
766 delete osthread;
767 return false;
768 }
769
770 // The thread is returned suspended (in state INITIALIZED),
771 // and is started higher up in the call chain
772 assert(state == INITIALIZED, "race condition");
773 return true;
774 }
775
776 /////////////////////////////////////////////////////////////////////////////
777 // attach existing thread
778
779 // bootstrap the main thread
780 bool os::create_main_thread(JavaThread* thread) {
781 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
782 return create_attached_thread(thread);
783 }
784
785 bool os::create_attached_thread(JavaThread* thread) {
786 #ifdef ASSERT
787 thread->verify_not_published();
788 #endif
789
790 // Allocate the OSThread object
791 OSThread* osthread = new OSThread(NULL, NULL);
792
793 if (osthread == NULL) {
794 return false;
795 }
796
797 // Store pthread info into the OSThread
798 osthread->set_thread_id(os::Linux::gettid());
799 osthread->set_pthread_id(::pthread_self());
800
801 // initialize floating point control register
802 os::Linux::init_thread_fpu_state();
803
804 // Initial thread state is RUNNABLE
805 osthread->set_state(RUNNABLE);
806
807 thread->set_osthread(osthread);
808
809 if (UseNUMA) {
810 int lgrp_id = os::numa_get_group_id();
811 if (lgrp_id != -1) {
812 thread->set_lgrp_id(lgrp_id);
813 }
814 }
815
816 if (os::Linux::is_initial_thread()) {
817 // If current thread is initial thread, its stack is mapped on demand,
818 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
819 // the entire stack region to avoid SEGV in stack banging.
820 // It is also useful to get around the heap-stack-gap problem on SuSE
821 // kernel (see 4821821 for details). We first expand stack to the top
822 // of yellow zone, then enable stack yellow zone (order is significant,
823 // enabling yellow zone first will crash JVM on SuSE Linux), so there
824 // is no gap between the last two virtual memory regions.
825
826 JavaThread *jt = (JavaThread *)thread;
827 address addr = jt->stack_reserved_zone_base();
828 assert(addr != NULL, "initialization problem?");
829 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
830
831 osthread->set_expanding_stack();
832 os::Linux::manually_expand_stack(jt, addr);
833 osthread->clear_expanding_stack();
834 }
835
836 // initialize signal mask for this thread
837 // and save the caller's signal mask
838 os::Linux::hotspot_sigmask(thread);
839
840 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
841 os::current_thread_id(), (uintx) pthread_self());
842
843 return true;
844 }
845
846 void os::pd_start_thread(Thread* thread) {
847 OSThread * osthread = thread->osthread();
848 assert(osthread->get_state() != INITIALIZED, "just checking");
849 Monitor* sync_with_child = osthread->startThread_lock();
850 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
851 sync_with_child->notify();
852 }
853
854 // Free Linux resources related to the OSThread
855 void os::free_thread(OSThread* osthread) {
856 assert(osthread != NULL, "osthread not set");
857
858 // We are told to free resources of the argument thread,
859 // but we can only really operate on the current thread.
860 assert(Thread::current()->osthread() == osthread,
861 "os::free_thread but not current thread");
862
863 #ifdef ASSERT
864 sigset_t current;
865 sigemptyset(¤t);
866 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
867 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
868 #endif
869
870 // Restore caller's signal mask
871 sigset_t sigmask = osthread->caller_sigmask();
872 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
873
874 delete osthread;
875 }
876
877 //////////////////////////////////////////////////////////////////////////////
878 // initial thread
879
880 // Check if current thread is the initial thread, similar to Solaris thr_main.
881 bool os::Linux::is_initial_thread(void) {
882 char dummy;
883 // If called before init complete, thread stack bottom will be null.
884 // Can be called if fatal error occurs before initialization.
885 if (initial_thread_stack_bottom() == NULL) return false;
886 assert(initial_thread_stack_bottom() != NULL &&
887 initial_thread_stack_size() != 0,
888 "os::init did not locate initial thread's stack region");
889 if ((address)&dummy >= initial_thread_stack_bottom() &&
890 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
891 return true;
892 } else {
893 return false;
894 }
895 }
896
897 // Find the virtual memory area that contains addr
898 static bool find_vma(address addr, address* vma_low, address* vma_high) {
899 FILE *fp = fopen("/proc/self/maps", "r");
900 if (fp) {
901 address low, high;
902 while (!feof(fp)) {
903 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
904 if (low <= addr && addr < high) {
905 if (vma_low) *vma_low = low;
906 if (vma_high) *vma_high = high;
907 fclose(fp);
908 return true;
909 }
910 }
911 for (;;) {
912 int ch = fgetc(fp);
913 if (ch == EOF || ch == (int)'\n') break;
914 }
915 }
916 fclose(fp);
917 }
918 return false;
919 }
920
921 // Locate initial thread stack. This special handling of initial thread stack
922 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
923 // bogus value for the primordial process thread. While the launcher has created
924 // the VM in a new thread since JDK 6, we still have to allow for the use of the
925 // JNI invocation API from a primordial thread.
926 void os::Linux::capture_initial_stack(size_t max_size) {
927
928 // max_size is either 0 (which means accept OS default for thread stacks) or
929 // a user-specified value known to be at least the minimum needed. If we
930 // are actually on the primordial thread we can make it appear that we have a
931 // smaller max_size stack by inserting the guard pages at that location. But we
932 // cannot do anything to emulate a larger stack than what has been provided by
933 // the OS or threading library. In fact if we try to use a stack greater than
934 // what is set by rlimit then we will crash the hosting process.
935
936 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
937 // If this is "unlimited" then it will be a huge value.
938 struct rlimit rlim;
939 getrlimit(RLIMIT_STACK, &rlim);
940 size_t stack_size = rlim.rlim_cur;
941
942 // 6308388: a bug in ld.so will relocate its own .data section to the
943 // lower end of primordial stack; reduce ulimit -s value a little bit
944 // so we won't install guard page on ld.so's data section.
945 stack_size -= 2 * page_size();
946
947 // Try to figure out where the stack base (top) is. This is harder.
948 //
949 // When an application is started, glibc saves the initial stack pointer in
950 // a global variable "__libc_stack_end", which is then used by system
951 // libraries. __libc_stack_end should be pretty close to stack top. The
952 // variable is available since the very early days. However, because it is
953 // a private interface, it could disappear in the future.
954 //
955 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
956 // to __libc_stack_end, it is very close to stack top, but isn't the real
957 // stack top. Note that /proc may not exist if VM is running as a chroot
958 // program, so reading /proc/<pid>/stat could fail. Also the contents of
959 // /proc/<pid>/stat could change in the future (though unlikely).
960 //
961 // We try __libc_stack_end first. If that doesn't work, look for
962 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
963 // as a hint, which should work well in most cases.
964
965 uintptr_t stack_start;
966
967 // try __libc_stack_end first
968 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
969 if (p && *p) {
970 stack_start = *p;
971 } else {
972 // see if we can get the start_stack field from /proc/self/stat
973 FILE *fp;
974 int pid;
975 char state;
976 int ppid;
977 int pgrp;
978 int session;
979 int nr;
980 int tpgrp;
981 unsigned long flags;
982 unsigned long minflt;
983 unsigned long cminflt;
984 unsigned long majflt;
985 unsigned long cmajflt;
986 unsigned long utime;
987 unsigned long stime;
988 long cutime;
989 long cstime;
990 long prio;
991 long nice;
992 long junk;
993 long it_real;
994 uintptr_t start;
995 uintptr_t vsize;
996 intptr_t rss;
997 uintptr_t rsslim;
998 uintptr_t scodes;
999 uintptr_t ecode;
1000 int i;
1001
1002 // Figure what the primordial thread stack base is. Code is inspired
1003 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1004 // followed by command name surrounded by parentheses, state, etc.
1005 char stat[2048];
1006 int statlen;
1007
1008 fp = fopen("/proc/self/stat", "r");
1009 if (fp) {
1010 statlen = fread(stat, 1, 2047, fp);
1011 stat[statlen] = '\0';
1012 fclose(fp);
1013
1014 // Skip pid and the command string. Note that we could be dealing with
1015 // weird command names, e.g. user could decide to rename java launcher
1016 // to "java 1.4.2 :)", then the stat file would look like
1017 // 1234 (java 1.4.2 :)) R ... ...
1018 // We don't really need to know the command string, just find the last
1019 // occurrence of ")" and then start parsing from there. See bug 4726580.
1020 char * s = strrchr(stat, ')');
1021
1022 i = 0;
1023 if (s) {
1024 // Skip blank chars
1025 do { s++; } while (s && isspace(*s));
1026
1027 #define _UFM UINTX_FORMAT
1028 #define _DFM INTX_FORMAT
1029
1030 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1031 // 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
1032 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,
1033 &state, // 3 %c
1034 &ppid, // 4 %d
1035 &pgrp, // 5 %d
1036 &session, // 6 %d
1037 &nr, // 7 %d
1038 &tpgrp, // 8 %d
1039 &flags, // 9 %lu
1040 &minflt, // 10 %lu
1041 &cminflt, // 11 %lu
1042 &majflt, // 12 %lu
1043 &cmajflt, // 13 %lu
1044 &utime, // 14 %lu
1045 &stime, // 15 %lu
1046 &cutime, // 16 %ld
1047 &cstime, // 17 %ld
1048 &prio, // 18 %ld
1049 &nice, // 19 %ld
1050 &junk, // 20 %ld
1051 &it_real, // 21 %ld
1052 &start, // 22 UINTX_FORMAT
1053 &vsize, // 23 UINTX_FORMAT
1054 &rss, // 24 INTX_FORMAT
1055 &rsslim, // 25 UINTX_FORMAT
1056 &scodes, // 26 UINTX_FORMAT
1057 &ecode, // 27 UINTX_FORMAT
1058 &stack_start); // 28 UINTX_FORMAT
1059 }
1060
1061 #undef _UFM
1062 #undef _DFM
1063
1064 if (i != 28 - 2) {
1065 assert(false, "Bad conversion from /proc/self/stat");
1066 // product mode - assume we are the initial thread, good luck in the
1067 // embedded case.
1068 warning("Can't detect initial thread stack location - bad conversion");
1069 stack_start = (uintptr_t) &rlim;
1070 }
1071 } else {
1072 // For some reason we can't open /proc/self/stat (for example, running on
1073 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1074 // most cases, so don't abort:
1075 warning("Can't detect initial thread stack location - no /proc/self/stat");
1076 stack_start = (uintptr_t) &rlim;
1077 }
1078 }
1079
1080 // Now we have a pointer (stack_start) very close to the stack top, the
1081 // next thing to do is to figure out the exact location of stack top. We
1082 // can find out the virtual memory area that contains stack_start by
1083 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1084 // and its upper limit is the real stack top. (again, this would fail if
1085 // running inside chroot, because /proc may not exist.)
1086
1087 uintptr_t stack_top;
1088 address low, high;
1089 if (find_vma((address)stack_start, &low, &high)) {
1090 // success, "high" is the true stack top. (ignore "low", because initial
1091 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1092 stack_top = (uintptr_t)high;
1093 } else {
1094 // failed, likely because /proc/self/maps does not exist
1095 warning("Can't detect initial thread stack location - find_vma failed");
1096 // best effort: stack_start is normally within a few pages below the real
1097 // stack top, use it as stack top, and reduce stack size so we won't put
1098 // guard page outside stack.
1099 stack_top = stack_start;
1100 stack_size -= 16 * page_size();
1101 }
1102
1103 // stack_top could be partially down the page so align it
1104 stack_top = align_size_up(stack_top, page_size());
1105
1106 // Allowed stack value is minimum of max_size and what we derived from rlimit
1107 if (max_size > 0) {
1108 _initial_thread_stack_size = MIN2(max_size, stack_size);
1109 } else {
1110 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1111 // clamp it at 8MB as we do on Solaris
1112 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1113 }
1114 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1115 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1116
1117 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1118
1119 if (log_is_enabled(Info, os, thread)) {
1120 // See if we seem to be on primordial process thread
1121 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1122 uintptr_t(&rlim) < stack_top;
1123
1124 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1125 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1126 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1127 stack_top, intptr_t(_initial_thread_stack_bottom));
1128 }
1129 }
1130
1131 ////////////////////////////////////////////////////////////////////////////////
1132 // time support
1133
1134 // Time since start-up in seconds to a fine granularity.
1135 // Used by VMSelfDestructTimer and the MemProfiler.
1136 double os::elapsedTime() {
1137
1138 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1139 }
1140
1141 jlong os::elapsed_counter() {
1142 return javaTimeNanos() - initial_time_count;
1143 }
1144
1145 jlong os::elapsed_frequency() {
1146 return NANOSECS_PER_SEC; // nanosecond resolution
1147 }
1148
1149 bool os::supports_vtime() { return true; }
1150 bool os::enable_vtime() { return false; }
1151 bool os::vtime_enabled() { return false; }
1152
1153 double os::elapsedVTime() {
1154 struct rusage usage;
1155 int retval = getrusage(RUSAGE_THREAD, &usage);
1156 if (retval == 0) {
1157 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);
1158 } else {
1159 // better than nothing, but not much
1160 return elapsedTime();
1161 }
1162 }
1163
1164 jlong os::javaTimeMillis() {
1165 timeval time;
1166 int status = gettimeofday(&time, NULL);
1167 assert(status != -1, "linux error");
1168 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1169 }
1170
1171 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1172 timeval time;
1173 int status = gettimeofday(&time, NULL);
1174 assert(status != -1, "linux error");
1175 seconds = jlong(time.tv_sec);
1176 nanos = jlong(time.tv_usec) * 1000;
1177 }
1178
1179
1180 #ifndef CLOCK_MONOTONIC
1181 #define CLOCK_MONOTONIC (1)
1182 #endif
1183
1184 void os::Linux::clock_init() {
1185 // we do dlopen's in this particular order due to bug in linux
1186 // dynamical loader (see 6348968) leading to crash on exit
1187 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1188 if (handle == NULL) {
1189 handle = dlopen("librt.so", RTLD_LAZY);
1190 }
1191
1192 if (handle) {
1193 int (*clock_getres_func)(clockid_t, struct timespec*) =
1194 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1195 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1196 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1197 if (clock_getres_func && clock_gettime_func) {
1198 // See if monotonic clock is supported by the kernel. Note that some
1199 // early implementations simply return kernel jiffies (updated every
1200 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1201 // for nano time (though the monotonic property is still nice to have).
1202 // It's fixed in newer kernels, however clock_getres() still returns
1203 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1204 // resolution for now. Hopefully as people move to new kernels, this
1205 // won't be a problem.
1206 struct timespec res;
1207 struct timespec tp;
1208 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1209 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1210 // yes, monotonic clock is supported
1211 _clock_gettime = clock_gettime_func;
1212 return;
1213 } else {
1214 // close librt if there is no monotonic clock
1215 dlclose(handle);
1216 }
1217 }
1218 }
1219 warning("No monotonic clock was available - timed services may " \
1220 "be adversely affected if the time-of-day clock changes");
1221 }
1222
1223 #ifndef SYS_clock_getres
1224 #if defined(X86) || defined(PPC64) || defined(S390)
1225 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261)
1226 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1227 #else
1228 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1229 #define sys_clock_getres(x,y) -1
1230 #endif
1231 #else
1232 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1233 #endif
1234
1235 void os::Linux::fast_thread_clock_init() {
1236 if (!UseLinuxPosixThreadCPUClocks) {
1237 return;
1238 }
1239 clockid_t clockid;
1240 struct timespec tp;
1241 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1242 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1243
1244 // Switch to using fast clocks for thread cpu time if
1245 // the sys_clock_getres() returns 0 error code.
1246 // Note, that some kernels may support the current thread
1247 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1248 // returned by the pthread_getcpuclockid().
1249 // If the fast Posix clocks are supported then the sys_clock_getres()
1250 // must return at least tp.tv_sec == 0 which means a resolution
1251 // better than 1 sec. This is extra check for reliability.
1252
1253 if (pthread_getcpuclockid_func &&
1254 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1255 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1256 _supports_fast_thread_cpu_time = true;
1257 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1258 }
1259 }
1260
1261 jlong os::javaTimeNanos() {
1262 if (os::supports_monotonic_clock()) {
1263 struct timespec tp;
1264 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1265 assert(status == 0, "gettime error");
1266 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1267 return result;
1268 } else {
1269 timeval time;
1270 int status = gettimeofday(&time, NULL);
1271 assert(status != -1, "linux error");
1272 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1273 return 1000 * usecs;
1274 }
1275 }
1276
1277 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1278 if (os::supports_monotonic_clock()) {
1279 info_ptr->max_value = ALL_64_BITS;
1280
1281 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1282 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1283 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1284 } else {
1285 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1286 info_ptr->max_value = ALL_64_BITS;
1287
1288 // gettimeofday is a real time clock so it skips
1289 info_ptr->may_skip_backward = true;
1290 info_ptr->may_skip_forward = true;
1291 }
1292
1293 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1294 }
1295
1296 // Return the real, user, and system times in seconds from an
1297 // arbitrary fixed point in the past.
1298 bool os::getTimesSecs(double* process_real_time,
1299 double* process_user_time,
1300 double* process_system_time) {
1301 struct tms ticks;
1302 clock_t real_ticks = times(&ticks);
1303
1304 if (real_ticks == (clock_t) (-1)) {
1305 return false;
1306 } else {
1307 double ticks_per_second = (double) clock_tics_per_sec;
1308 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1309 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1310 *process_real_time = ((double) real_ticks) / ticks_per_second;
1311
1312 return true;
1313 }
1314 }
1315
1316
1317 char * os::local_time_string(char *buf, size_t buflen) {
1318 struct tm t;
1319 time_t long_time;
1320 time(&long_time);
1321 localtime_r(&long_time, &t);
1322 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1323 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1324 t.tm_hour, t.tm_min, t.tm_sec);
1325 return buf;
1326 }
1327
1328 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1329 return localtime_r(clock, res);
1330 }
1331
1332 ////////////////////////////////////////////////////////////////////////////////
1333 // runtime exit support
1334
1335 // Note: os::shutdown() might be called very early during initialization, or
1336 // called from signal handler. Before adding something to os::shutdown(), make
1337 // sure it is async-safe and can handle partially initialized VM.
1338 void os::shutdown() {
1339
1340 // allow PerfMemory to attempt cleanup of any persistent resources
1341 perfMemory_exit();
1342
1343 // needs to remove object in file system
1344 AttachListener::abort();
1345
1346 // flush buffered output, finish log files
1347 ostream_abort();
1348
1349 // Check for abort hook
1350 abort_hook_t abort_hook = Arguments::abort_hook();
1351 if (abort_hook != NULL) {
1352 abort_hook();
1353 }
1354
1355 }
1356
1357 // Note: os::abort() might be called very early during initialization, or
1358 // called from signal handler. Before adding something to os::abort(), make
1359 // sure it is async-safe and can handle partially initialized VM.
1360 void os::abort(bool dump_core, void* siginfo, const void* context) {
1361 os::shutdown();
1362 if (dump_core) {
1363 #ifndef PRODUCT
1364 fdStream out(defaultStream::output_fd());
1365 out.print_raw("Current thread is ");
1366 char buf[16];
1367 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1368 out.print_raw_cr(buf);
1369 out.print_raw_cr("Dumping core ...");
1370 #endif
1371 ::abort(); // dump core
1372 }
1373
1374 ::exit(1);
1375 }
1376
1377 // Die immediately, no exit hook, no abort hook, no cleanup.
1378 void os::die() {
1379 ::abort();
1380 }
1381
1382
1383 // This method is a copy of JDK's sysGetLastErrorString
1384 // from src/solaris/hpi/src/system_md.c
1385
1386 size_t os::lasterror(char *buf, size_t len) {
1387 if (errno == 0) return 0;
1388
1389 const char *s = os::strerror(errno);
1390 size_t n = ::strlen(s);
1391 if (n >= len) {
1392 n = len - 1;
1393 }
1394 ::strncpy(buf, s, n);
1395 buf[n] = '\0';
1396 return n;
1397 }
1398
1399 // thread_id is kernel thread id (similar to Solaris LWP id)
1400 intx os::current_thread_id() { return os::Linux::gettid(); }
1401 int os::current_process_id() {
1402 return ::getpid();
1403 }
1404
1405 // DLL functions
1406
1407 const char* os::dll_file_extension() { return ".so"; }
1408
1409 // This must be hard coded because it's the system's temporary
1410 // directory not the java application's temp directory, ala java.io.tmpdir.
1411 const char* os::get_temp_directory() { return "/tmp"; }
1412
1413 static bool file_exists(const char* filename) {
1414 struct stat statbuf;
1415 if (filename == NULL || strlen(filename) == 0) {
1416 return false;
1417 }
1418 return os::stat(filename, &statbuf) == 0;
1419 }
1420
1421 bool os::dll_build_name(char* buffer, size_t buflen,
1422 const char* pname, const char* fname) {
1423 bool retval = false;
1424 // Copied from libhpi
1425 const size_t pnamelen = pname ? strlen(pname) : 0;
1426
1427 // Return error on buffer overflow.
1428 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1429 return retval;
1430 }
1431
1432 if (pnamelen == 0) {
1433 snprintf(buffer, buflen, "lib%s.so", fname);
1434 retval = true;
1435 } else if (strchr(pname, *os::path_separator()) != NULL) {
1436 int n;
1437 char** pelements = split_path(pname, &n);
1438 if (pelements == NULL) {
1439 return false;
1440 }
1441 for (int i = 0; i < n; i++) {
1442 // Really shouldn't be NULL, but check can't hurt
1443 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1444 continue; // skip the empty path values
1445 }
1446 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1447 if (file_exists(buffer)) {
1448 retval = true;
1449 break;
1450 }
1451 }
1452 // release the storage
1453 for (int i = 0; i < n; i++) {
1454 if (pelements[i] != NULL) {
1455 FREE_C_HEAP_ARRAY(char, pelements[i]);
1456 }
1457 }
1458 if (pelements != NULL) {
1459 FREE_C_HEAP_ARRAY(char*, pelements);
1460 }
1461 } else {
1462 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1463 retval = true;
1464 }
1465 return retval;
1466 }
1467
1468 // check if addr is inside libjvm.so
1469 bool os::address_is_in_vm(address addr) {
1470 static address libjvm_base_addr;
1471 Dl_info dlinfo;
1472
1473 if (libjvm_base_addr == NULL) {
1474 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1475 libjvm_base_addr = (address)dlinfo.dli_fbase;
1476 }
1477 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1478 }
1479
1480 if (dladdr((void *)addr, &dlinfo) != 0) {
1481 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1482 }
1483
1484 return false;
1485 }
1486
1487 bool os::dll_address_to_function_name(address addr, char *buf,
1488 int buflen, int *offset,
1489 bool demangle) {
1490 // buf is not optional, but offset is optional
1491 assert(buf != NULL, "sanity check");
1492
1493 Dl_info dlinfo;
1494
1495 if (dladdr((void*)addr, &dlinfo) != 0) {
1496 // see if we have a matching symbol
1497 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1498 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1499 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1500 }
1501 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1502 return true;
1503 }
1504 // no matching symbol so try for just file info
1505 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1506 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1507 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1508 return true;
1509 }
1510 }
1511 }
1512
1513 buf[0] = '\0';
1514 if (offset != NULL) *offset = -1;
1515 return false;
1516 }
1517
1518 struct _address_to_library_name {
1519 address addr; // input : memory address
1520 size_t buflen; // size of fname
1521 char* fname; // output: library name
1522 address base; // library base addr
1523 };
1524
1525 static int address_to_library_name_callback(struct dl_phdr_info *info,
1526 size_t size, void *data) {
1527 int i;
1528 bool found = false;
1529 address libbase = NULL;
1530 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1531
1532 // iterate through all loadable segments
1533 for (i = 0; i < info->dlpi_phnum; i++) {
1534 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1535 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1536 // base address of a library is the lowest address of its loaded
1537 // segments.
1538 if (libbase == NULL || libbase > segbase) {
1539 libbase = segbase;
1540 }
1541 // see if 'addr' is within current segment
1542 if (segbase <= d->addr &&
1543 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1544 found = true;
1545 }
1546 }
1547 }
1548
1549 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1550 // so dll_address_to_library_name() can fall through to use dladdr() which
1551 // can figure out executable name from argv[0].
1552 if (found && info->dlpi_name && info->dlpi_name[0]) {
1553 d->base = libbase;
1554 if (d->fname) {
1555 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1556 }
1557 return 1;
1558 }
1559 return 0;
1560 }
1561
1562 bool os::dll_address_to_library_name(address addr, char* buf,
1563 int buflen, int* offset) {
1564 // buf is not optional, but offset is optional
1565 assert(buf != NULL, "sanity check");
1566
1567 Dl_info dlinfo;
1568 struct _address_to_library_name data;
1569
1570 // There is a bug in old glibc dladdr() implementation that it could resolve
1571 // to wrong library name if the .so file has a base address != NULL. Here
1572 // we iterate through the program headers of all loaded libraries to find
1573 // out which library 'addr' really belongs to. This workaround can be
1574 // removed once the minimum requirement for glibc is moved to 2.3.x.
1575 data.addr = addr;
1576 data.fname = buf;
1577 data.buflen = buflen;
1578 data.base = NULL;
1579 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1580
1581 if (rslt) {
1582 // buf already contains library name
1583 if (offset) *offset = addr - data.base;
1584 return true;
1585 }
1586 if (dladdr((void*)addr, &dlinfo) != 0) {
1587 if (dlinfo.dli_fname != NULL) {
1588 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1589 }
1590 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1591 *offset = addr - (address)dlinfo.dli_fbase;
1592 }
1593 return true;
1594 }
1595
1596 buf[0] = '\0';
1597 if (offset) *offset = -1;
1598 return false;
1599 }
1600
1601 // Loads .dll/.so and
1602 // in case of error it checks if .dll/.so was built for the
1603 // same architecture as Hotspot is running on
1604
1605
1606 // Remember the stack's state. The Linux dynamic linker will change
1607 // the stack to 'executable' at most once, so we must safepoint only once.
1608 bool os::Linux::_stack_is_executable = false;
1609
1610 // VM operation that loads a library. This is necessary if stack protection
1611 // of the Java stacks can be lost during loading the library. If we
1612 // do not stop the Java threads, they can stack overflow before the stacks
1613 // are protected again.
1614 class VM_LinuxDllLoad: public VM_Operation {
1615 private:
1616 const char *_filename;
1617 char *_ebuf;
1618 int _ebuflen;
1619 void *_lib;
1620 public:
1621 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1622 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1623 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1624 void doit() {
1625 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1626 os::Linux::_stack_is_executable = true;
1627 }
1628 void* loaded_library() { return _lib; }
1629 };
1630
1631 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1632 void * result = NULL;
1633 bool load_attempted = false;
1634
1635 // Check whether the library to load might change execution rights
1636 // of the stack. If they are changed, the protection of the stack
1637 // guard pages will be lost. We need a safepoint to fix this.
1638 //
1639 // See Linux man page execstack(8) for more info.
1640 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1641 ElfFile ef(filename);
1642 if (!ef.specifies_noexecstack()) {
1643 if (!is_init_completed()) {
1644 os::Linux::_stack_is_executable = true;
1645 // This is OK - No Java threads have been created yet, and hence no
1646 // stack guard pages to fix.
1647 //
1648 // This should happen only when you are building JDK7 using a very
1649 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1650 //
1651 // Dynamic loader will make all stacks executable after
1652 // this function returns, and will not do that again.
1653 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1654 } else {
1655 warning("You have loaded library %s which might have disabled stack guard. "
1656 "The VM will try to fix the stack guard now.\n"
1657 "It's highly recommended that you fix the library with "
1658 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1659 filename);
1660
1661 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1662 JavaThread *jt = JavaThread::current();
1663 if (jt->thread_state() != _thread_in_native) {
1664 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1665 // that requires ExecStack. Cannot enter safe point. Let's give up.
1666 warning("Unable to fix stack guard. Giving up.");
1667 } else {
1668 if (!LoadExecStackDllInVMThread) {
1669 // This is for the case where the DLL has an static
1670 // constructor function that executes JNI code. We cannot
1671 // load such DLLs in the VMThread.
1672 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1673 }
1674
1675 ThreadInVMfromNative tiv(jt);
1676 debug_only(VMNativeEntryWrapper vew;)
1677
1678 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1679 VMThread::execute(&op);
1680 if (LoadExecStackDllInVMThread) {
1681 result = op.loaded_library();
1682 }
1683 load_attempted = true;
1684 }
1685 }
1686 }
1687 }
1688
1689 if (!load_attempted) {
1690 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1691 }
1692
1693 if (result != NULL) {
1694 // Successful loading
1695 return result;
1696 }
1697
1698 Elf32_Ehdr elf_head;
1699 int diag_msg_max_length=ebuflen-strlen(ebuf);
1700 char* diag_msg_buf=ebuf+strlen(ebuf);
1701
1702 if (diag_msg_max_length==0) {
1703 // No more space in ebuf for additional diagnostics message
1704 return NULL;
1705 }
1706
1707
1708 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1709
1710 if (file_descriptor < 0) {
1711 // Can't open library, report dlerror() message
1712 return NULL;
1713 }
1714
1715 bool failed_to_read_elf_head=
1716 (sizeof(elf_head)!=
1717 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1718
1719 ::close(file_descriptor);
1720 if (failed_to_read_elf_head) {
1721 // file i/o error - report dlerror() msg
1722 return NULL;
1723 }
1724
1725 typedef struct {
1726 Elf32_Half code; // Actual value as defined in elf.h
1727 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1728 unsigned char elf_class; // 32 or 64 bit
1729 unsigned char endianess; // MSB or LSB
1730 char* name; // String representation
1731 } arch_t;
1732
1733 #ifndef EM_486
1734 #define EM_486 6 /* Intel 80486 */
1735 #endif
1736 #ifndef EM_AARCH64
1737 #define EM_AARCH64 183 /* ARM AARCH64 */
1738 #endif
1739
1740 static const arch_t arch_array[]={
1741 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1742 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1743 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1744 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1745 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1746 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1747 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1748 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1749 #if defined(VM_LITTLE_ENDIAN)
1750 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1751 #else
1752 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1753 #endif
1754 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1755 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1756 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1757 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1758 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1759 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1760 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1761 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1762 };
1763
1764 #if (defined IA32)
1765 static Elf32_Half running_arch_code=EM_386;
1766 #elif (defined AMD64)
1767 static Elf32_Half running_arch_code=EM_X86_64;
1768 #elif (defined IA64)
1769 static Elf32_Half running_arch_code=EM_IA_64;
1770 #elif (defined __sparc) && (defined _LP64)
1771 static Elf32_Half running_arch_code=EM_SPARCV9;
1772 #elif (defined __sparc) && (!defined _LP64)
1773 static Elf32_Half running_arch_code=EM_SPARC;
1774 #elif (defined __powerpc64__)
1775 static Elf32_Half running_arch_code=EM_PPC64;
1776 #elif (defined __powerpc__)
1777 static Elf32_Half running_arch_code=EM_PPC;
1778 #elif (defined AARCH64)
1779 static Elf32_Half running_arch_code=EM_AARCH64;
1780 #elif (defined ARM)
1781 static Elf32_Half running_arch_code=EM_ARM;
1782 #elif (defined S390)
1783 static Elf32_Half running_arch_code=EM_S390;
1784 #elif (defined ALPHA)
1785 static Elf32_Half running_arch_code=EM_ALPHA;
1786 #elif (defined MIPSEL)
1787 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1788 #elif (defined PARISC)
1789 static Elf32_Half running_arch_code=EM_PARISC;
1790 #elif (defined MIPS)
1791 static Elf32_Half running_arch_code=EM_MIPS;
1792 #elif (defined M68K)
1793 static Elf32_Half running_arch_code=EM_68K;
1794 #else
1795 #error Method os::dll_load requires that one of following is defined:\
1796 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc
1797 #endif
1798
1799 // Identify compatability class for VM's architecture and library's architecture
1800 // Obtain string descriptions for architectures
1801
1802 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1803 int running_arch_index=-1;
1804
1805 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1806 if (running_arch_code == arch_array[i].code) {
1807 running_arch_index = i;
1808 }
1809 if (lib_arch.code == arch_array[i].code) {
1810 lib_arch.compat_class = arch_array[i].compat_class;
1811 lib_arch.name = arch_array[i].name;
1812 }
1813 }
1814
1815 assert(running_arch_index != -1,
1816 "Didn't find running architecture code (running_arch_code) in arch_array");
1817 if (running_arch_index == -1) {
1818 // Even though running architecture detection failed
1819 // we may still continue with reporting dlerror() message
1820 return NULL;
1821 }
1822
1823 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1824 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1825 return NULL;
1826 }
1827
1828 #ifndef S390
1829 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1830 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1831 return NULL;
1832 }
1833 #endif // !S390
1834
1835 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1836 if (lib_arch.name!=NULL) {
1837 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1838 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1839 lib_arch.name, arch_array[running_arch_index].name);
1840 } else {
1841 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1842 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1843 lib_arch.code,
1844 arch_array[running_arch_index].name);
1845 }
1846 }
1847
1848 return NULL;
1849 }
1850
1851 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1852 int ebuflen) {
1853 void * result = ::dlopen(filename, RTLD_LAZY);
1854 if (result == NULL) {
1855 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1856 ebuf[ebuflen-1] = '\0';
1857 }
1858 return result;
1859 }
1860
1861 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1862 int ebuflen) {
1863 void * result = NULL;
1864 if (LoadExecStackDllInVMThread) {
1865 result = dlopen_helper(filename, ebuf, ebuflen);
1866 }
1867
1868 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1869 // library that requires an executable stack, or which does not have this
1870 // stack attribute set, dlopen changes the stack attribute to executable. The
1871 // read protection of the guard pages gets lost.
1872 //
1873 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1874 // may have been queued at the same time.
1875
1876 if (!_stack_is_executable) {
1877 JavaThread *jt = Threads::first();
1878
1879 while (jt) {
1880 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1881 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1882 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1883 warning("Attempt to reguard stack yellow zone failed.");
1884 }
1885 }
1886 jt = jt->next();
1887 }
1888 }
1889
1890 return result;
1891 }
1892
1893 void* os::dll_lookup(void* handle, const char* name) {
1894 void* res = dlsym(handle, name);
1895 return res;
1896 }
1897
1898 void* os::get_default_process_handle() {
1899 return (void*)::dlopen(NULL, RTLD_LAZY);
1900 }
1901
1902 static bool _print_ascii_file(const char* filename, outputStream* st) {
1903 int fd = ::open(filename, O_RDONLY);
1904 if (fd == -1) {
1905 return false;
1906 }
1907
1908 char buf[33];
1909 int bytes;
1910 buf[32] = '\0';
1911 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1912 st->print_raw(buf, bytes);
1913 }
1914
1915 ::close(fd);
1916
1917 return true;
1918 }
1919
1920 void os::print_dll_info(outputStream *st) {
1921 st->print_cr("Dynamic libraries:");
1922
1923 char fname[32];
1924 pid_t pid = os::Linux::gettid();
1925
1926 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1927
1928 if (!_print_ascii_file(fname, st)) {
1929 st->print("Can not get library information for pid = %d\n", pid);
1930 }
1931 }
1932
1933 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1934 FILE *procmapsFile = NULL;
1935
1936 // Open the procfs maps file for the current process
1937 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1938 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1939 char line[PATH_MAX + 100];
1940
1941 // Read line by line from 'file'
1942 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1943 u8 base, top, offset, inode;
1944 char permissions[5];
1945 char device[6];
1946 char name[PATH_MAX + 1];
1947
1948 // Parse fields from line
1949 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1950 &base, &top, permissions, &offset, device, &inode, name);
1951
1952 // Filter by device id '00:00' so that we only get file system mapped files.
1953 if (strcmp(device, "00:00") != 0) {
1954
1955 // Call callback with the fields of interest
1956 if(callback(name, (address)base, (address)top, param)) {
1957 // Oops abort, callback aborted
1958 fclose(procmapsFile);
1959 return 1;
1960 }
1961 }
1962 }
1963 fclose(procmapsFile);
1964 }
1965 return 0;
1966 }
1967
1968 void os::print_os_info_brief(outputStream* st) {
1969 os::Linux::print_distro_info(st);
1970
1971 os::Posix::print_uname_info(st);
1972
1973 os::Linux::print_libversion_info(st);
1974
1975 }
1976
1977 void os::print_os_info(outputStream* st) {
1978 st->print("OS:");
1979
1980 os::Linux::print_distro_info(st);
1981
1982 os::Posix::print_uname_info(st);
1983
1984 // Print warning if unsafe chroot environment detected
1985 if (unsafe_chroot_detected) {
1986 st->print("WARNING!! ");
1987 st->print_cr("%s", unstable_chroot_error);
1988 }
1989
1990 os::Linux::print_libversion_info(st);
1991
1992 os::Posix::print_rlimit_info(st);
1993
1994 os::Posix::print_load_average(st);
1995
1996 os::Linux::print_full_memory_info(st);
1997 }
1998
1999 // Try to identify popular distros.
2000 // Most Linux distributions have a /etc/XXX-release file, which contains
2001 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2002 // file that also contains the OS version string. Some have more than one
2003 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2004 // /etc/redhat-release.), so the order is important.
2005 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2006 // their own specific XXX-release file as well as a redhat-release file.
2007 // Because of this the XXX-release file needs to be searched for before the
2008 // redhat-release file.
2009 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2010 // search for redhat-release / SuSE-release needs to be before lsb-release.
2011 // Since the lsb-release file is the new standard it needs to be searched
2012 // before the older style release files.
2013 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2014 // next to last resort. The os-release file is a new standard that contains
2015 // distribution information and the system-release file seems to be an old
2016 // standard that has been replaced by the lsb-release and os-release files.
2017 // Searching for the debian_version file is the last resort. It contains
2018 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2019 // "Debian " is printed before the contents of the debian_version file.
2020
2021 const char* distro_files[] = {
2022 "/etc/oracle-release",
2023 "/etc/mandriva-release",
2024 "/etc/mandrake-release",
2025 "/etc/sun-release",
2026 "/etc/redhat-release",
2027 "/etc/SuSE-release",
2028 "/etc/lsb-release",
2029 "/etc/turbolinux-release",
2030 "/etc/gentoo-release",
2031 "/etc/ltib-release",
2032 "/etc/angstrom-version",
2033 "/etc/system-release",
2034 "/etc/os-release",
2035 NULL };
2036
2037 void os::Linux::print_distro_info(outputStream* st) {
2038 for (int i = 0;; i++) {
2039 const char* file = distro_files[i];
2040 if (file == NULL) {
2041 break; // done
2042 }
2043 // If file prints, we found it.
2044 if (_print_ascii_file(file, st)) {
2045 return;
2046 }
2047 }
2048
2049 if (file_exists("/etc/debian_version")) {
2050 st->print("Debian ");
2051 _print_ascii_file("/etc/debian_version", st);
2052 } else {
2053 st->print("Linux");
2054 }
2055 st->cr();
2056 }
2057
2058 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2059 char buf[256];
2060 while (fgets(buf, sizeof(buf), fp)) {
2061 // Edit out extra stuff in expected format
2062 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2063 char* ptr = strstr(buf, "\""); // the name is in quotes
2064 if (ptr != NULL) {
2065 ptr++; // go beyond first quote
2066 char* nl = strchr(ptr, '\"');
2067 if (nl != NULL) *nl = '\0';
2068 strncpy(distro, ptr, length);
2069 } else {
2070 ptr = strstr(buf, "=");
2071 ptr++; // go beyond equals then
2072 char* nl = strchr(ptr, '\n');
2073 if (nl != NULL) *nl = '\0';
2074 strncpy(distro, ptr, length);
2075 }
2076 return;
2077 } else if (get_first_line) {
2078 char* nl = strchr(buf, '\n');
2079 if (nl != NULL) *nl = '\0';
2080 strncpy(distro, buf, length);
2081 return;
2082 }
2083 }
2084 // print last line and close
2085 char* nl = strchr(buf, '\n');
2086 if (nl != NULL) *nl = '\0';
2087 strncpy(distro, buf, length);
2088 }
2089
2090 static void parse_os_info(char* distro, size_t length, const char* file) {
2091 FILE* fp = fopen(file, "r");
2092 if (fp != NULL) {
2093 // if suse format, print out first line
2094 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2095 parse_os_info_helper(fp, distro, length, get_first_line);
2096 fclose(fp);
2097 }
2098 }
2099
2100 void os::get_summary_os_info(char* buf, size_t buflen) {
2101 for (int i = 0;; i++) {
2102 const char* file = distro_files[i];
2103 if (file == NULL) {
2104 break; // ran out of distro_files
2105 }
2106 if (file_exists(file)) {
2107 parse_os_info(buf, buflen, file);
2108 return;
2109 }
2110 }
2111 // special case for debian
2112 if (file_exists("/etc/debian_version")) {
2113 strncpy(buf, "Debian ", buflen);
2114 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2115 } else {
2116 strncpy(buf, "Linux", buflen);
2117 }
2118 }
2119
2120 void os::Linux::print_libversion_info(outputStream* st) {
2121 // libc, pthread
2122 st->print("libc:");
2123 st->print("%s ", os::Linux::glibc_version());
2124 st->print("%s ", os::Linux::libpthread_version());
2125 st->cr();
2126 }
2127
2128 void os::Linux::print_full_memory_info(outputStream* st) {
2129 st->print("\n/proc/meminfo:\n");
2130 _print_ascii_file("/proc/meminfo", st);
2131 st->cr();
2132 }
2133
2134 void os::print_memory_info(outputStream* st) {
2135
2136 st->print("Memory:");
2137 st->print(" %dk page", os::vm_page_size()>>10);
2138
2139 // values in struct sysinfo are "unsigned long"
2140 struct sysinfo si;
2141 sysinfo(&si);
2142
2143 st->print(", physical " UINT64_FORMAT "k",
2144 os::physical_memory() >> 10);
2145 st->print("(" UINT64_FORMAT "k free)",
2146 os::available_memory() >> 10);
2147 st->print(", swap " UINT64_FORMAT "k",
2148 ((jlong)si.totalswap * si.mem_unit) >> 10);
2149 st->print("(" UINT64_FORMAT "k free)",
2150 ((jlong)si.freeswap * si.mem_unit) >> 10);
2151 st->cr();
2152 }
2153
2154 // Print the first "model name" line and the first "flags" line
2155 // that we find and nothing more. We assume "model name" comes
2156 // before "flags" so if we find a second "model name", then the
2157 // "flags" field is considered missing.
2158 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2159 #if defined(IA32) || defined(AMD64)
2160 // Other platforms have less repetitive cpuinfo files
2161 FILE *fp = fopen("/proc/cpuinfo", "r");
2162 if (fp) {
2163 while (!feof(fp)) {
2164 if (fgets(buf, buflen, fp)) {
2165 // Assume model name comes before flags
2166 bool model_name_printed = false;
2167 if (strstr(buf, "model name") != NULL) {
2168 if (!model_name_printed) {
2169 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2170 st->print_raw(buf);
2171 model_name_printed = true;
2172 } else {
2173 // model name printed but not flags? Odd, just return
2174 fclose(fp);
2175 return true;
2176 }
2177 }
2178 // print the flags line too
2179 if (strstr(buf, "flags") != NULL) {
2180 st->print_raw(buf);
2181 fclose(fp);
2182 return true;
2183 }
2184 }
2185 }
2186 fclose(fp);
2187 }
2188 #endif // x86 platforms
2189 return false;
2190 }
2191
2192 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2193 // Only print the model name if the platform provides this as a summary
2194 if (!print_model_name_and_flags(st, buf, buflen)) {
2195 st->print("\n/proc/cpuinfo:\n");
2196 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2197 st->print_cr(" <Not Available>");
2198 }
2199 }
2200 }
2201
2202 #if defined(AMD64) || defined(IA32) || defined(X32)
2203 const char* search_string = "model name";
2204 #elif defined(PPC64)
2205 const char* search_string = "cpu";
2206 #elif defined(S390)
2207 const char* search_string = "processor";
2208 #elif defined(SPARC)
2209 const char* search_string = "cpu";
2210 #else
2211 const char* search_string = "Processor";
2212 #endif
2213
2214 // Parses the cpuinfo file for string representing the model name.
2215 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2216 FILE* fp = fopen("/proc/cpuinfo", "r");
2217 if (fp != NULL) {
2218 while (!feof(fp)) {
2219 char buf[256];
2220 if (fgets(buf, sizeof(buf), fp)) {
2221 char* start = strstr(buf, search_string);
2222 if (start != NULL) {
2223 char *ptr = start + strlen(search_string);
2224 char *end = buf + strlen(buf);
2225 while (ptr != end) {
2226 // skip whitespace and colon for the rest of the name.
2227 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2228 break;
2229 }
2230 ptr++;
2231 }
2232 if (ptr != end) {
2233 // reasonable string, get rid of newline and keep the rest
2234 char* nl = strchr(buf, '\n');
2235 if (nl != NULL) *nl = '\0';
2236 strncpy(cpuinfo, ptr, length);
2237 fclose(fp);
2238 return;
2239 }
2240 }
2241 }
2242 }
2243 fclose(fp);
2244 }
2245 // cpuinfo not found or parsing failed, just print generic string. The entire
2246 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2247 #if defined(AARCH64)
2248 strncpy(cpuinfo, "AArch64", length);
2249 #elif defined(AMD64)
2250 strncpy(cpuinfo, "x86_64", length);
2251 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2252 strncpy(cpuinfo, "ARM", length);
2253 #elif defined(IA32)
2254 strncpy(cpuinfo, "x86_32", length);
2255 #elif defined(IA64)
2256 strncpy(cpuinfo, "IA64", length);
2257 #elif defined(PPC)
2258 strncpy(cpuinfo, "PPC64", length);
2259 #elif defined(S390)
2260 strncpy(cpuinfo, "S390", length);
2261 #elif defined(SPARC)
2262 strncpy(cpuinfo, "sparcv9", length);
2263 #elif defined(ZERO_LIBARCH)
2264 strncpy(cpuinfo, ZERO_LIBARCH, length);
2265 #else
2266 strncpy(cpuinfo, "unknown", length);
2267 #endif
2268 }
2269
2270 static void print_signal_handler(outputStream* st, int sig,
2271 char* buf, size_t buflen);
2272
2273 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2274 st->print_cr("Signal Handlers:");
2275 print_signal_handler(st, SIGSEGV, buf, buflen);
2276 print_signal_handler(st, SIGBUS , buf, buflen);
2277 print_signal_handler(st, SIGFPE , buf, buflen);
2278 print_signal_handler(st, SIGPIPE, buf, buflen);
2279 print_signal_handler(st, SIGXFSZ, buf, buflen);
2280 print_signal_handler(st, SIGILL , buf, buflen);
2281 print_signal_handler(st, SR_signum, buf, buflen);
2282 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2283 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2284 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2285 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2286 #if defined(PPC64)
2287 print_signal_handler(st, SIGTRAP, buf, buflen);
2288 #endif
2289 }
2290
2291 static char saved_jvm_path[MAXPATHLEN] = {0};
2292
2293 // Find the full path to the current module, libjvm.so
2294 void os::jvm_path(char *buf, jint buflen) {
2295 // Error checking.
2296 if (buflen < MAXPATHLEN) {
2297 assert(false, "must use a large-enough buffer");
2298 buf[0] = '\0';
2299 return;
2300 }
2301 // Lazy resolve the path to current module.
2302 if (saved_jvm_path[0] != 0) {
2303 strcpy(buf, saved_jvm_path);
2304 return;
2305 }
2306
2307 char dli_fname[MAXPATHLEN];
2308 bool ret = dll_address_to_library_name(
2309 CAST_FROM_FN_PTR(address, os::jvm_path),
2310 dli_fname, sizeof(dli_fname), NULL);
2311 assert(ret, "cannot locate libjvm");
2312 char *rp = NULL;
2313 if (ret && dli_fname[0] != '\0') {
2314 rp = os::Posix::realpath(dli_fname, buf, buflen);
2315 }
2316 if (rp == NULL) {
2317 return;
2318 }
2319
2320 if (Arguments::sun_java_launcher_is_altjvm()) {
2321 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2322 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2323 // If "/jre/lib/" appears at the right place in the string, then
2324 // assume we are installed in a JDK and we're done. Otherwise, check
2325 // for a JAVA_HOME environment variable and fix up the path so it
2326 // looks like libjvm.so is installed there (append a fake suffix
2327 // hotspot/libjvm.so).
2328 const char *p = buf + strlen(buf) - 1;
2329 for (int count = 0; p > buf && count < 5; ++count) {
2330 for (--p; p > buf && *p != '/'; --p)
2331 /* empty */ ;
2332 }
2333
2334 if (strncmp(p, "/jre/lib/", 9) != 0) {
2335 // Look for JAVA_HOME in the environment.
2336 char* java_home_var = ::getenv("JAVA_HOME");
2337 if (java_home_var != NULL && java_home_var[0] != 0) {
2338 char* jrelib_p;
2339 int len;
2340
2341 // Check the current module name "libjvm.so".
2342 p = strrchr(buf, '/');
2343 if (p == NULL) {
2344 return;
2345 }
2346 assert(strstr(p, "/libjvm") == p, "invalid library name");
2347
2348 rp = os::Posix::realpath(java_home_var, buf, buflen);
2349 if (rp == NULL) {
2350 return;
2351 }
2352
2353 // determine if this is a legacy image or modules image
2354 // modules image doesn't have "jre" subdirectory
2355 len = strlen(buf);
2356 assert(len < buflen, "Ran out of buffer room");
2357 jrelib_p = buf + len;
2358 snprintf(jrelib_p, buflen-len, "/jre/lib");
2359 if (0 != access(buf, F_OK)) {
2360 snprintf(jrelib_p, buflen-len, "/lib");
2361 }
2362
2363 if (0 == access(buf, F_OK)) {
2364 // Use current module name "libjvm.so"
2365 len = strlen(buf);
2366 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2367 } else {
2368 // Go back to path of .so
2369 rp = os::Posix::realpath(dli_fname, buf, buflen);
2370 if (rp == NULL) {
2371 return;
2372 }
2373 }
2374 }
2375 }
2376 }
2377
2378 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2379 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2380 }
2381
2382 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2383 // no prefix required, not even "_"
2384 }
2385
2386 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2387 // no suffix required
2388 }
2389
2390 ////////////////////////////////////////////////////////////////////////////////
2391 // sun.misc.Signal support
2392
2393 static volatile jint sigint_count = 0;
2394
2395 static void UserHandler(int sig, void *siginfo, void *context) {
2396 // 4511530 - sem_post is serialized and handled by the manager thread. When
2397 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2398 // don't want to flood the manager thread with sem_post requests.
2399 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2400 return;
2401 }
2402
2403 // Ctrl-C is pressed during error reporting, likely because the error
2404 // handler fails to abort. Let VM die immediately.
2405 if (sig == SIGINT && is_error_reported()) {
2406 os::die();
2407 }
2408
2409 os::signal_notify(sig);
2410 }
2411
2412 void* os::user_handler() {
2413 return CAST_FROM_FN_PTR(void*, UserHandler);
2414 }
2415
2416 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2417 struct timespec ts;
2418 // Semaphore's are always associated with CLOCK_REALTIME
2419 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2420 // see unpackTime for discussion on overflow checking
2421 if (sec >= MAX_SECS) {
2422 ts.tv_sec += MAX_SECS;
2423 ts.tv_nsec = 0;
2424 } else {
2425 ts.tv_sec += sec;
2426 ts.tv_nsec += nsec;
2427 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2428 ts.tv_nsec -= NANOSECS_PER_SEC;
2429 ++ts.tv_sec; // note: this must be <= max_secs
2430 }
2431 }
2432
2433 return ts;
2434 }
2435
2436 extern "C" {
2437 typedef void (*sa_handler_t)(int);
2438 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2439 }
2440
2441 void* os::signal(int signal_number, void* handler) {
2442 struct sigaction sigAct, oldSigAct;
2443
2444 sigfillset(&(sigAct.sa_mask));
2445 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2446 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2447
2448 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2449 // -1 means registration failed
2450 return (void *)-1;
2451 }
2452
2453 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2454 }
2455
2456 void os::signal_raise(int signal_number) {
2457 ::raise(signal_number);
2458 }
2459
2460 // The following code is moved from os.cpp for making this
2461 // code platform specific, which it is by its very nature.
2462
2463 // Will be modified when max signal is changed to be dynamic
2464 int os::sigexitnum_pd() {
2465 return NSIG;
2466 }
2467
2468 // a counter for each possible signal value
2469 static volatile jint pending_signals[NSIG+1] = { 0 };
2470
2471 // Linux(POSIX) specific hand shaking semaphore.
2472 static sem_t sig_sem;
2473 static PosixSemaphore sr_semaphore;
2474
2475 void os::signal_init_pd() {
2476 // Initialize signal structures
2477 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2478
2479 // Initialize signal semaphore
2480 ::sem_init(&sig_sem, 0, 0);
2481 }
2482
2483 void os::signal_notify(int sig) {
2484 Atomic::inc(&pending_signals[sig]);
2485 ::sem_post(&sig_sem);
2486 }
2487
2488 static int check_pending_signals(bool wait) {
2489 Atomic::store(0, &sigint_count);
2490 for (;;) {
2491 for (int i = 0; i < NSIG + 1; i++) {
2492 jint n = pending_signals[i];
2493 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2494 return i;
2495 }
2496 }
2497 if (!wait) {
2498 return -1;
2499 }
2500 JavaThread *thread = JavaThread::current();
2501 ThreadBlockInVM tbivm(thread);
2502
2503 bool threadIsSuspended;
2504 do {
2505 thread->set_suspend_equivalent();
2506 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2507 ::sem_wait(&sig_sem);
2508
2509 // were we externally suspended while we were waiting?
2510 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2511 if (threadIsSuspended) {
2512 // The semaphore has been incremented, but while we were waiting
2513 // another thread suspended us. We don't want to continue running
2514 // while suspended because that would surprise the thread that
2515 // suspended us.
2516 ::sem_post(&sig_sem);
2517
2518 thread->java_suspend_self();
2519 }
2520 } while (threadIsSuspended);
2521 }
2522 }
2523
2524 int os::signal_lookup() {
2525 return check_pending_signals(false);
2526 }
2527
2528 int os::signal_wait() {
2529 return check_pending_signals(true);
2530 }
2531
2532 ////////////////////////////////////////////////////////////////////////////////
2533 // Virtual Memory
2534
2535 int os::vm_page_size() {
2536 // Seems redundant as all get out
2537 assert(os::Linux::page_size() != -1, "must call os::init");
2538 return os::Linux::page_size();
2539 }
2540
2541 // Solaris allocates memory by pages.
2542 int os::vm_allocation_granularity() {
2543 assert(os::Linux::page_size() != -1, "must call os::init");
2544 return os::Linux::page_size();
2545 }
2546
2547 // Rationale behind this function:
2548 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2549 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2550 // samples for JITted code. Here we create private executable mapping over the code cache
2551 // and then we can use standard (well, almost, as mapping can change) way to provide
2552 // info for the reporting script by storing timestamp and location of symbol
2553 void linux_wrap_code(char* base, size_t size) {
2554 static volatile jint cnt = 0;
2555
2556 if (!UseOprofile) {
2557 return;
2558 }
2559
2560 char buf[PATH_MAX+1];
2561 int num = Atomic::add(1, &cnt);
2562
2563 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2564 os::get_temp_directory(), os::current_process_id(), num);
2565 unlink(buf);
2566
2567 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2568
2569 if (fd != -1) {
2570 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2571 if (rv != (off_t)-1) {
2572 if (::write(fd, "", 1) == 1) {
2573 mmap(base, size,
2574 PROT_READ|PROT_WRITE|PROT_EXEC,
2575 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2576 }
2577 }
2578 ::close(fd);
2579 unlink(buf);
2580 }
2581 }
2582
2583 static bool recoverable_mmap_error(int err) {
2584 // See if the error is one we can let the caller handle. This
2585 // list of errno values comes from JBS-6843484. I can't find a
2586 // Linux man page that documents this specific set of errno
2587 // values so while this list currently matches Solaris, it may
2588 // change as we gain experience with this failure mode.
2589 switch (err) {
2590 case EBADF:
2591 case EINVAL:
2592 case ENOTSUP:
2593 // let the caller deal with these errors
2594 return true;
2595
2596 default:
2597 // Any remaining errors on this OS can cause our reserved mapping
2598 // to be lost. That can cause confusion where different data
2599 // structures think they have the same memory mapped. The worst
2600 // scenario is if both the VM and a library think they have the
2601 // same memory mapped.
2602 return false;
2603 }
2604 }
2605
2606 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2607 int err) {
2608 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2609 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2610 os::strerror(err), err);
2611 }
2612
2613 static void warn_fail_commit_memory(char* addr, size_t size,
2614 size_t alignment_hint, bool exec,
2615 int err) {
2616 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2617 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2618 alignment_hint, exec, os::strerror(err), err);
2619 }
2620
2621 // NOTE: Linux kernel does not really reserve the pages for us.
2622 // All it does is to check if there are enough free pages
2623 // left at the time of mmap(). This could be a potential
2624 // problem.
2625 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2626 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2627 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2628 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2629 if (res != (uintptr_t) MAP_FAILED) {
2630 if (UseNUMAInterleaving) {
2631 numa_make_global(addr, size);
2632 }
2633 return 0;
2634 }
2635
2636 int err = errno; // save errno from mmap() call above
2637
2638 if (!recoverable_mmap_error(err)) {
2639 warn_fail_commit_memory(addr, size, exec, err);
2640 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2641 }
2642
2643 return err;
2644 }
2645
2646 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2647 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2648 }
2649
2650 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2651 const char* mesg) {
2652 assert(mesg != NULL, "mesg must be specified");
2653 int err = os::Linux::commit_memory_impl(addr, size, exec);
2654 if (err != 0) {
2655 // the caller wants all commit errors to exit with the specified mesg:
2656 warn_fail_commit_memory(addr, size, exec, err);
2657 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2658 }
2659 }
2660
2661 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2662 #ifndef MAP_HUGETLB
2663 #define MAP_HUGETLB 0x40000
2664 #endif
2665
2666 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2667 #ifndef MADV_HUGEPAGE
2668 #define MADV_HUGEPAGE 14
2669 #endif
2670
2671 int os::Linux::commit_memory_impl(char* addr, size_t size,
2672 size_t alignment_hint, bool exec) {
2673 int err = os::Linux::commit_memory_impl(addr, size, exec);
2674 if (err == 0) {
2675 realign_memory(addr, size, alignment_hint);
2676 }
2677 return err;
2678 }
2679
2680 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2681 bool exec) {
2682 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2683 }
2684
2685 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2686 size_t alignment_hint, bool exec,
2687 const char* mesg) {
2688 assert(mesg != NULL, "mesg must be specified");
2689 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2690 if (err != 0) {
2691 // the caller wants all commit errors to exit with the specified mesg:
2692 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2693 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2694 }
2695 }
2696
2697 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2698 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2699 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2700 // be supported or the memory may already be backed by huge pages.
2701 ::madvise(addr, bytes, MADV_HUGEPAGE);
2702 }
2703 }
2704
2705 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2706 // This method works by doing an mmap over an existing mmaping and effectively discarding
2707 // the existing pages. However it won't work for SHM-based large pages that cannot be
2708 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2709 // small pages on top of the SHM segment. This method always works for small pages, so we
2710 // allow that in any case.
2711 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2712 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2713 }
2714 }
2715
2716 void os::numa_make_global(char *addr, size_t bytes) {
2717 Linux::numa_interleave_memory(addr, bytes);
2718 }
2719
2720 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2721 // bind policy to MPOL_PREFERRED for the current thread.
2722 #define USE_MPOL_PREFERRED 0
2723
2724 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2725 // To make NUMA and large pages more robust when both enabled, we need to ease
2726 // the requirements on where the memory should be allocated. MPOL_BIND is the
2727 // default policy and it will force memory to be allocated on the specified
2728 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2729 // the specified node, but will not force it. Using this policy will prevent
2730 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2731 // free large pages.
2732 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2733 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2734 }
2735
2736 bool os::numa_topology_changed() { return false; }
2737
2738 size_t os::numa_get_groups_num() {
2739 // Return just the number of nodes in which it's possible to allocate memory
2740 // (in numa terminology, configured nodes).
2741 return Linux::numa_num_configured_nodes();
2742 }
2743
2744 int os::numa_get_group_id() {
2745 int cpu_id = Linux::sched_getcpu();
2746 if (cpu_id != -1) {
2747 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2748 if (lgrp_id != -1) {
2749 return lgrp_id;
2750 }
2751 }
2752 return 0;
2753 }
2754
2755 int os::Linux::get_existing_num_nodes() {
2756 size_t node;
2757 size_t highest_node_number = Linux::numa_max_node();
2758 int num_nodes = 0;
2759
2760 // Get the total number of nodes in the system including nodes without memory.
2761 for (node = 0; node <= highest_node_number; node++) {
2762 if (isnode_in_existing_nodes(node)) {
2763 num_nodes++;
2764 }
2765 }
2766 return num_nodes;
2767 }
2768
2769 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2770 size_t highest_node_number = Linux::numa_max_node();
2771 size_t i = 0;
2772
2773 // Map all node ids in which is possible to allocate memory. Also nodes are
2774 // not always consecutively available, i.e. available from 0 to the highest
2775 // node number.
2776 for (size_t node = 0; node <= highest_node_number; node++) {
2777 if (Linux::isnode_in_configured_nodes(node)) {
2778 ids[i++] = node;
2779 }
2780 }
2781 return i;
2782 }
2783
2784 bool os::get_page_info(char *start, page_info* info) {
2785 return false;
2786 }
2787
2788 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2789 page_info* page_found) {
2790 return end;
2791 }
2792
2793
2794 int os::Linux::sched_getcpu_syscall(void) {
2795 unsigned int cpu = 0;
2796 int retval = -1;
2797
2798 #if defined(IA32)
2799 #ifndef SYS_getcpu
2800 #define SYS_getcpu 318
2801 #endif
2802 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2803 #elif defined(AMD64)
2804 // Unfortunately we have to bring all these macros here from vsyscall.h
2805 // to be able to compile on old linuxes.
2806 #define __NR_vgetcpu 2
2807 #define VSYSCALL_START (-10UL << 20)
2808 #define VSYSCALL_SIZE 1024
2809 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2810 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2811 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2812 retval = vgetcpu(&cpu, NULL, NULL);
2813 #endif
2814
2815 return (retval == -1) ? retval : cpu;
2816 }
2817
2818 // Something to do with the numa-aware allocator needs these symbols
2819 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2820 extern "C" JNIEXPORT void numa_error(char *where) { }
2821
2822
2823 // If we are running with libnuma version > 2, then we should
2824 // be trying to use symbols with versions 1.1
2825 // If we are running with earlier version, which did not have symbol versions,
2826 // we should use the base version.
2827 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2828 void *f = dlvsym(handle, name, "libnuma_1.1");
2829 if (f == NULL) {
2830 f = dlsym(handle, name);
2831 }
2832 return f;
2833 }
2834
2835 bool os::Linux::libnuma_init() {
2836 // sched_getcpu() should be in libc.
2837 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2838 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2839
2840 // If it's not, try a direct syscall.
2841 if (sched_getcpu() == -1) {
2842 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2843 (void*)&sched_getcpu_syscall));
2844 }
2845
2846 if (sched_getcpu() != -1) { // Does it work?
2847 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2848 if (handle != NULL) {
2849 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2850 libnuma_dlsym(handle, "numa_node_to_cpus")));
2851 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2852 libnuma_dlsym(handle, "numa_max_node")));
2853 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
2854 libnuma_dlsym(handle, "numa_num_configured_nodes")));
2855 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2856 libnuma_dlsym(handle, "numa_available")));
2857 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2858 libnuma_dlsym(handle, "numa_tonode_memory")));
2859 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2860 libnuma_dlsym(handle, "numa_interleave_memory")));
2861 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2862 libnuma_dlsym(handle, "numa_set_bind_policy")));
2863 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
2864 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
2865 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
2866 libnuma_dlsym(handle, "numa_distance")));
2867
2868 if (numa_available() != -1) {
2869 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2870 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
2871 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
2872 // Create an index -> node mapping, since nodes are not always consecutive
2873 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2874 rebuild_nindex_to_node_map();
2875 // Create a cpu -> node mapping
2876 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2877 rebuild_cpu_to_node_map();
2878 return true;
2879 }
2880 }
2881 }
2882 return false;
2883 }
2884
2885 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
2886 // Creating guard page is very expensive. Java thread has HotSpot
2887 // guard pages, only enable glibc guard page for non-Java threads.
2888 // (Remember: compiler thread is a Java thread, too!)
2889 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
2890 }
2891
2892 void os::Linux::rebuild_nindex_to_node_map() {
2893 int highest_node_number = Linux::numa_max_node();
2894
2895 nindex_to_node()->clear();
2896 for (int node = 0; node <= highest_node_number; node++) {
2897 if (Linux::isnode_in_existing_nodes(node)) {
2898 nindex_to_node()->append(node);
2899 }
2900 }
2901 }
2902
2903 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2904 // The table is later used in get_node_by_cpu().
2905 void os::Linux::rebuild_cpu_to_node_map() {
2906 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2907 // in libnuma (possible values are starting from 16,
2908 // and continuing up with every other power of 2, but less
2909 // than the maximum number of CPUs supported by kernel), and
2910 // is a subject to change (in libnuma version 2 the requirements
2911 // are more reasonable) we'll just hardcode the number they use
2912 // in the library.
2913 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2914
2915 size_t cpu_num = processor_count();
2916 size_t cpu_map_size = NCPUS / BitsPerCLong;
2917 size_t cpu_map_valid_size =
2918 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2919
2920 cpu_to_node()->clear();
2921 cpu_to_node()->at_grow(cpu_num - 1);
2922
2923 size_t node_num = get_existing_num_nodes();
2924
2925 int distance = 0;
2926 int closest_distance = INT_MAX;
2927 int closest_node = 0;
2928 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2929 for (size_t i = 0; i < node_num; i++) {
2930 // Check if node is configured (not a memory-less node). If it is not, find
2931 // the closest configured node.
2932 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) {
2933 closest_distance = INT_MAX;
2934 // Check distance from all remaining nodes in the system. Ignore distance
2935 // from itself and from another non-configured node.
2936 for (size_t m = 0; m < node_num; m++) {
2937 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) {
2938 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
2939 // If a closest node is found, update. There is always at least one
2940 // configured node in the system so there is always at least one node
2941 // close.
2942 if (distance != 0 && distance < closest_distance) {
2943 closest_distance = distance;
2944 closest_node = nindex_to_node()->at(m);
2945 }
2946 }
2947 }
2948 } else {
2949 // Current node is already a configured node.
2950 closest_node = nindex_to_node()->at(i);
2951 }
2952
2953 // Get cpus from the original node and map them to the closest node. If node
2954 // is a configured node (not a memory-less node), then original node and
2955 // closest node are the same.
2956 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2957 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2958 if (cpu_map[j] != 0) {
2959 for (size_t k = 0; k < BitsPerCLong; k++) {
2960 if (cpu_map[j] & (1UL << k)) {
2961 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
2962 }
2963 }
2964 }
2965 }
2966 }
2967 }
2968 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2969 }
2970
2971 int os::Linux::get_node_by_cpu(int cpu_id) {
2972 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2973 return cpu_to_node()->at(cpu_id);
2974 }
2975 return -1;
2976 }
2977
2978 GrowableArray<int>* os::Linux::_cpu_to_node;
2979 GrowableArray<int>* os::Linux::_nindex_to_node;
2980 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2981 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2982 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2983 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
2984 os::Linux::numa_available_func_t os::Linux::_numa_available;
2985 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2986 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2987 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2988 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
2989 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
2990 unsigned long* os::Linux::_numa_all_nodes;
2991 struct bitmask* os::Linux::_numa_all_nodes_ptr;
2992 struct bitmask* os::Linux::_numa_nodes_ptr;
2993
2994 bool os::pd_uncommit_memory(char* addr, size_t size) {
2995 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2996 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2997 return res != (uintptr_t) MAP_FAILED;
2998 }
2999
3000 static address get_stack_commited_bottom(address bottom, size_t size) {
3001 address nbot = bottom;
3002 address ntop = bottom + size;
3003
3004 size_t page_sz = os::vm_page_size();
3005 unsigned pages = size / page_sz;
3006
3007 unsigned char vec[1];
3008 unsigned imin = 1, imax = pages + 1, imid;
3009 int mincore_return_value = 0;
3010
3011 assert(imin <= imax, "Unexpected page size");
3012
3013 while (imin < imax) {
3014 imid = (imax + imin) / 2;
3015 nbot = ntop - (imid * page_sz);
3016
3017 // Use a trick with mincore to check whether the page is mapped or not.
3018 // mincore sets vec to 1 if page resides in memory and to 0 if page
3019 // is swapped output but if page we are asking for is unmapped
3020 // it returns -1,ENOMEM
3021 mincore_return_value = mincore(nbot, page_sz, vec);
3022
3023 if (mincore_return_value == -1) {
3024 // Page is not mapped go up
3025 // to find first mapped page
3026 if (errno != EAGAIN) {
3027 assert(errno == ENOMEM, "Unexpected mincore errno");
3028 imax = imid;
3029 }
3030 } else {
3031 // Page is mapped go down
3032 // to find first not mapped page
3033 imin = imid + 1;
3034 }
3035 }
3036
3037 nbot = nbot + page_sz;
3038
3039 // Adjust stack bottom one page up if last checked page is not mapped
3040 if (mincore_return_value == -1) {
3041 nbot = nbot + page_sz;
3042 }
3043
3044 return nbot;
3045 }
3046
3047
3048 // Linux uses a growable mapping for the stack, and if the mapping for
3049 // the stack guard pages is not removed when we detach a thread the
3050 // stack cannot grow beyond the pages where the stack guard was
3051 // mapped. If at some point later in the process the stack expands to
3052 // that point, the Linux kernel cannot expand the stack any further
3053 // because the guard pages are in the way, and a segfault occurs.
3054 //
3055 // However, it's essential not to split the stack region by unmapping
3056 // a region (leaving a hole) that's already part of the stack mapping,
3057 // so if the stack mapping has already grown beyond the guard pages at
3058 // the time we create them, we have to truncate the stack mapping.
3059 // So, we need to know the extent of the stack mapping when
3060 // create_stack_guard_pages() is called.
3061
3062 // We only need this for stacks that are growable: at the time of
3063 // writing thread stacks don't use growable mappings (i.e. those
3064 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3065 // only applies to the main thread.
3066
3067 // If the (growable) stack mapping already extends beyond the point
3068 // where we're going to put our guard pages, truncate the mapping at
3069 // that point by munmap()ping it. This ensures that when we later
3070 // munmap() the guard pages we don't leave a hole in the stack
3071 // mapping. This only affects the main/initial thread
3072
3073 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3074 if (os::Linux::is_initial_thread()) {
3075 // As we manually grow stack up to bottom inside create_attached_thread(),
3076 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3077 // we don't need to do anything special.
3078 // Check it first, before calling heavy function.
3079 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3080 unsigned char vec[1];
3081
3082 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3083 // Fallback to slow path on all errors, including EAGAIN
3084 stack_extent = (uintptr_t) get_stack_commited_bottom(
3085 os::Linux::initial_thread_stack_bottom(),
3086 (size_t)addr - stack_extent);
3087 }
3088
3089 if (stack_extent < (uintptr_t)addr) {
3090 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3091 }
3092 }
3093
3094 return os::commit_memory(addr, size, !ExecMem);
3095 }
3096
3097 // If this is a growable mapping, remove the guard pages entirely by
3098 // munmap()ping them. If not, just call uncommit_memory(). This only
3099 // affects the main/initial thread, but guard against future OS changes
3100 // It's safe to always unmap guard pages for initial thread because we
3101 // always place it right after end of the mapped region
3102
3103 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3104 uintptr_t stack_extent, stack_base;
3105
3106 if (os::Linux::is_initial_thread()) {
3107 return ::munmap(addr, size) == 0;
3108 }
3109
3110 return os::uncommit_memory(addr, size);
3111 }
3112
3113 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3114 // at 'requested_addr'. If there are existing memory mappings at the same
3115 // location, however, they will be overwritten. If 'fixed' is false,
3116 // 'requested_addr' is only treated as a hint, the return value may or
3117 // may not start from the requested address. Unlike Linux mmap(), this
3118 // function returns NULL to indicate failure.
3119 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3120 char * addr;
3121 int flags;
3122
3123 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3124 if (fixed) {
3125 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3126 flags |= MAP_FIXED;
3127 }
3128
3129 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3130 // touch an uncommitted page. Otherwise, the read/write might
3131 // succeed if we have enough swap space to back the physical page.
3132 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3133 flags, -1, 0);
3134
3135 return addr == MAP_FAILED ? NULL : addr;
3136 }
3137
3138 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3139 // (req_addr != NULL) or with a given alignment.
3140 // - bytes shall be a multiple of alignment.
3141 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3142 // - alignment sets the alignment at which memory shall be allocated.
3143 // It must be a multiple of allocation granularity.
3144 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3145 // req_addr or NULL.
3146 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3147
3148 size_t extra_size = bytes;
3149 if (req_addr == NULL && alignment > 0) {
3150 extra_size += alignment;
3151 }
3152
3153 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3154 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3155 -1, 0);
3156 if (start == MAP_FAILED) {
3157 start = NULL;
3158 } else {
3159 if (req_addr != NULL) {
3160 if (start != req_addr) {
3161 ::munmap(start, extra_size);
3162 start = NULL;
3163 }
3164 } else {
3165 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3166 char* const end_aligned = start_aligned + bytes;
3167 char* const end = start + extra_size;
3168 if (start_aligned > start) {
3169 ::munmap(start, start_aligned - start);
3170 }
3171 if (end_aligned < end) {
3172 ::munmap(end_aligned, end - end_aligned);
3173 }
3174 start = start_aligned;
3175 }
3176 }
3177 return start;
3178 }
3179
3180 static int anon_munmap(char * addr, size_t size) {
3181 return ::munmap(addr, size) == 0;
3182 }
3183
3184 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3185 size_t alignment_hint) {
3186 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3187 }
3188
3189 bool os::pd_release_memory(char* addr, size_t size) {
3190 return anon_munmap(addr, size);
3191 }
3192
3193 static bool linux_mprotect(char* addr, size_t size, int prot) {
3194 // Linux wants the mprotect address argument to be page aligned.
3195 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3196
3197 // According to SUSv3, mprotect() should only be used with mappings
3198 // established by mmap(), and mmap() always maps whole pages. Unaligned
3199 // 'addr' likely indicates problem in the VM (e.g. trying to change
3200 // protection of malloc'ed or statically allocated memory). Check the
3201 // caller if you hit this assert.
3202 assert(addr == bottom, "sanity check");
3203
3204 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3205 return ::mprotect(bottom, size, prot) == 0;
3206 }
3207
3208 // Set protections specified
3209 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3210 bool is_committed) {
3211 unsigned int p = 0;
3212 switch (prot) {
3213 case MEM_PROT_NONE: p = PROT_NONE; break;
3214 case MEM_PROT_READ: p = PROT_READ; break;
3215 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3216 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3217 default:
3218 ShouldNotReachHere();
3219 }
3220 // is_committed is unused.
3221 return linux_mprotect(addr, bytes, p);
3222 }
3223
3224 bool os::guard_memory(char* addr, size_t size) {
3225 return linux_mprotect(addr, size, PROT_NONE);
3226 }
3227
3228 bool os::unguard_memory(char* addr, size_t size) {
3229 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3230 }
3231
3232 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3233 size_t page_size) {
3234 bool result = false;
3235 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3236 MAP_ANONYMOUS|MAP_PRIVATE,
3237 -1, 0);
3238 if (p != MAP_FAILED) {
3239 void *aligned_p = align_ptr_up(p, page_size);
3240
3241 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3242
3243 munmap(p, page_size * 2);
3244 }
3245
3246 if (warn && !result) {
3247 warning("TransparentHugePages is not supported by the operating system.");
3248 }
3249
3250 return result;
3251 }
3252
3253 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3254 bool result = false;
3255 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3256 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3257 -1, 0);
3258
3259 if (p != MAP_FAILED) {
3260 // We don't know if this really is a huge page or not.
3261 FILE *fp = fopen("/proc/self/maps", "r");
3262 if (fp) {
3263 while (!feof(fp)) {
3264 char chars[257];
3265 long x = 0;
3266 if (fgets(chars, sizeof(chars), fp)) {
3267 if (sscanf(chars, "%lx-%*x", &x) == 1
3268 && x == (long)p) {
3269 if (strstr (chars, "hugepage")) {
3270 result = true;
3271 break;
3272 }
3273 }
3274 }
3275 }
3276 fclose(fp);
3277 }
3278 munmap(p, page_size);
3279 }
3280
3281 if (warn && !result) {
3282 warning("HugeTLBFS is not supported by the operating system.");
3283 }
3284
3285 return result;
3286 }
3287
3288 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3289 //
3290 // From the coredump_filter documentation:
3291 //
3292 // - (bit 0) anonymous private memory
3293 // - (bit 1) anonymous shared memory
3294 // - (bit 2) file-backed private memory
3295 // - (bit 3) file-backed shared memory
3296 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3297 // effective only if the bit 2 is cleared)
3298 // - (bit 5) hugetlb private memory
3299 // - (bit 6) hugetlb shared memory
3300 //
3301 static void set_coredump_filter(void) {
3302 FILE *f;
3303 long cdm;
3304
3305 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3306 return;
3307 }
3308
3309 if (fscanf(f, "%lx", &cdm) != 1) {
3310 fclose(f);
3311 return;
3312 }
3313
3314 rewind(f);
3315
3316 if ((cdm & LARGEPAGES_BIT) == 0) {
3317 cdm |= LARGEPAGES_BIT;
3318 fprintf(f, "%#lx", cdm);
3319 }
3320
3321 fclose(f);
3322 }
3323
3324 // Large page support
3325
3326 static size_t _large_page_size = 0;
3327
3328 size_t os::Linux::find_large_page_size() {
3329 size_t large_page_size = 0;
3330
3331 // large_page_size on Linux is used to round up heap size. x86 uses either
3332 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3333 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3334 // page as large as 256M.
3335 //
3336 // Here we try to figure out page size by parsing /proc/meminfo and looking
3337 // for a line with the following format:
3338 // Hugepagesize: 2048 kB
3339 //
3340 // If we can't determine the value (e.g. /proc is not mounted, or the text
3341 // format has been changed), we'll use the largest page size supported by
3342 // the processor.
3343
3344 #ifndef ZERO
3345 large_page_size =
3346 AARCH64_ONLY(2 * M)
3347 AMD64_ONLY(2 * M)
3348 ARM32_ONLY(2 * M)
3349 IA32_ONLY(4 * M)
3350 IA64_ONLY(256 * M)
3351 PPC_ONLY(4 * M)
3352 S390_ONLY(1 * M)
3353 SPARC_ONLY(4 * M);
3354 #endif // ZERO
3355
3356 FILE *fp = fopen("/proc/meminfo", "r");
3357 if (fp) {
3358 while (!feof(fp)) {
3359 int x = 0;
3360 char buf[16];
3361 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3362 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3363 large_page_size = x * K;
3364 break;
3365 }
3366 } else {
3367 // skip to next line
3368 for (;;) {
3369 int ch = fgetc(fp);
3370 if (ch == EOF || ch == (int)'\n') break;
3371 }
3372 }
3373 }
3374 fclose(fp);
3375 }
3376
3377 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3378 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3379 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3380 proper_unit_for_byte_size(large_page_size));
3381 }
3382
3383 return large_page_size;
3384 }
3385
3386 size_t os::Linux::setup_large_page_size() {
3387 _large_page_size = Linux::find_large_page_size();
3388 const size_t default_page_size = (size_t)Linux::page_size();
3389 if (_large_page_size > default_page_size) {
3390 _page_sizes[0] = _large_page_size;
3391 _page_sizes[1] = default_page_size;
3392 _page_sizes[2] = 0;
3393 }
3394
3395 return _large_page_size;
3396 }
3397
3398 bool os::Linux::setup_large_page_type(size_t page_size) {
3399 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3400 FLAG_IS_DEFAULT(UseSHM) &&
3401 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3402
3403 // The type of large pages has not been specified by the user.
3404
3405 // Try UseHugeTLBFS and then UseSHM.
3406 UseHugeTLBFS = UseSHM = true;
3407
3408 // Don't try UseTransparentHugePages since there are known
3409 // performance issues with it turned on. This might change in the future.
3410 UseTransparentHugePages = false;
3411 }
3412
3413 if (UseTransparentHugePages) {
3414 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3415 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3416 UseHugeTLBFS = false;
3417 UseSHM = false;
3418 return true;
3419 }
3420 UseTransparentHugePages = false;
3421 }
3422
3423 if (UseHugeTLBFS) {
3424 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3425 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3426 UseSHM = false;
3427 return true;
3428 }
3429 UseHugeTLBFS = false;
3430 }
3431
3432 return UseSHM;
3433 }
3434
3435 void os::large_page_init() {
3436 if (!UseLargePages &&
3437 !UseTransparentHugePages &&
3438 !UseHugeTLBFS &&
3439 !UseSHM) {
3440 // Not using large pages.
3441 return;
3442 }
3443
3444 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3445 // The user explicitly turned off large pages.
3446 // Ignore the rest of the large pages flags.
3447 UseTransparentHugePages = false;
3448 UseHugeTLBFS = false;
3449 UseSHM = false;
3450 return;
3451 }
3452
3453 size_t large_page_size = Linux::setup_large_page_size();
3454 UseLargePages = Linux::setup_large_page_type(large_page_size);
3455
3456 set_coredump_filter();
3457 }
3458
3459 #ifndef SHM_HUGETLB
3460 #define SHM_HUGETLB 04000
3461 #endif
3462
3463 #define shm_warning_format(format, ...) \
3464 do { \
3465 if (UseLargePages && \
3466 (!FLAG_IS_DEFAULT(UseLargePages) || \
3467 !FLAG_IS_DEFAULT(UseSHM) || \
3468 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3469 warning(format, __VA_ARGS__); \
3470 } \
3471 } while (0)
3472
3473 #define shm_warning(str) shm_warning_format("%s", str)
3474
3475 #define shm_warning_with_errno(str) \
3476 do { \
3477 int err = errno; \
3478 shm_warning_format(str " (error = %d)", err); \
3479 } while (0)
3480
3481 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3482 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3483
3484 if (!is_size_aligned(alignment, SHMLBA)) {
3485 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3486 return NULL;
3487 }
3488
3489 // To ensure that we get 'alignment' aligned memory from shmat,
3490 // we pre-reserve aligned virtual memory and then attach to that.
3491
3492 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3493 if (pre_reserved_addr == NULL) {
3494 // Couldn't pre-reserve aligned memory.
3495 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3496 return NULL;
3497 }
3498
3499 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3500 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3501
3502 if ((intptr_t)addr == -1) {
3503 int err = errno;
3504 shm_warning_with_errno("Failed to attach shared memory.");
3505
3506 assert(err != EACCES, "Unexpected error");
3507 assert(err != EIDRM, "Unexpected error");
3508 assert(err != EINVAL, "Unexpected error");
3509
3510 // Since we don't know if the kernel unmapped the pre-reserved memory area
3511 // we can't unmap it, since that would potentially unmap memory that was
3512 // mapped from other threads.
3513 return NULL;
3514 }
3515
3516 return addr;
3517 }
3518
3519 static char* shmat_at_address(int shmid, char* req_addr) {
3520 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3521 assert(false, "Requested address needs to be SHMLBA aligned");
3522 return NULL;
3523 }
3524
3525 char* addr = (char*)shmat(shmid, req_addr, 0);
3526
3527 if ((intptr_t)addr == -1) {
3528 shm_warning_with_errno("Failed to attach shared memory.");
3529 return NULL;
3530 }
3531
3532 return addr;
3533 }
3534
3535 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3536 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3537 if (req_addr != NULL) {
3538 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3539 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3540 return shmat_at_address(shmid, req_addr);
3541 }
3542
3543 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3544 // return large page size aligned memory addresses when req_addr == NULL.
3545 // However, if the alignment is larger than the large page size, we have
3546 // to manually ensure that the memory returned is 'alignment' aligned.
3547 if (alignment > os::large_page_size()) {
3548 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3549 return shmat_with_alignment(shmid, bytes, alignment);
3550 } else {
3551 return shmat_at_address(shmid, NULL);
3552 }
3553 }
3554
3555 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3556 char* req_addr, bool exec) {
3557 // "exec" is passed in but not used. Creating the shared image for
3558 // the code cache doesn't have an SHM_X executable permission to check.
3559 assert(UseLargePages && UseSHM, "only for SHM large pages");
3560 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3561 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3562
3563 if (!is_size_aligned(bytes, os::large_page_size())) {
3564 return NULL; // Fallback to small pages.
3565 }
3566
3567 // Create a large shared memory region to attach to based on size.
3568 // Currently, size is the total size of the heap.
3569 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3570 if (shmid == -1) {
3571 // Possible reasons for shmget failure:
3572 // 1. shmmax is too small for Java heap.
3573 // > check shmmax value: cat /proc/sys/kernel/shmmax
3574 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3575 // 2. not enough large page memory.
3576 // > check available large pages: cat /proc/meminfo
3577 // > increase amount of large pages:
3578 // echo new_value > /proc/sys/vm/nr_hugepages
3579 // Note 1: different Linux may use different name for this property,
3580 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3581 // Note 2: it's possible there's enough physical memory available but
3582 // they are so fragmented after a long run that they can't
3583 // coalesce into large pages. Try to reserve large pages when
3584 // the system is still "fresh".
3585 shm_warning_with_errno("Failed to reserve shared memory.");
3586 return NULL;
3587 }
3588
3589 // Attach to the region.
3590 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3591
3592 // Remove shmid. If shmat() is successful, the actual shared memory segment
3593 // will be deleted when it's detached by shmdt() or when the process
3594 // terminates. If shmat() is not successful this will remove the shared
3595 // segment immediately.
3596 shmctl(shmid, IPC_RMID, NULL);
3597
3598 return addr;
3599 }
3600
3601 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3602 int error) {
3603 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3604
3605 bool warn_on_failure = UseLargePages &&
3606 (!FLAG_IS_DEFAULT(UseLargePages) ||
3607 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3608 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3609
3610 if (warn_on_failure) {
3611 char msg[128];
3612 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3613 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3614 warning("%s", msg);
3615 }
3616 }
3617
3618 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3619 char* req_addr,
3620 bool exec) {
3621 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3622 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3623 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3624
3625 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3626 char* addr = (char*)::mmap(req_addr, bytes, prot,
3627 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3628 -1, 0);
3629
3630 if (addr == MAP_FAILED) {
3631 warn_on_large_pages_failure(req_addr, bytes, errno);
3632 return NULL;
3633 }
3634
3635 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3636
3637 return addr;
3638 }
3639
3640 // Reserve memory using mmap(MAP_HUGETLB).
3641 // - bytes shall be a multiple of alignment.
3642 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3643 // - alignment sets the alignment at which memory shall be allocated.
3644 // It must be a multiple of allocation granularity.
3645 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3646 // req_addr or NULL.
3647 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3648 size_t alignment,
3649 char* req_addr,
3650 bool exec) {
3651 size_t large_page_size = os::large_page_size();
3652 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3653
3654 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3655 assert(is_size_aligned(bytes, alignment), "Must be");
3656
3657 // First reserve - but not commit - the address range in small pages.
3658 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3659
3660 if (start == NULL) {
3661 return NULL;
3662 }
3663
3664 assert(is_ptr_aligned(start, alignment), "Must be");
3665
3666 char* end = start + bytes;
3667
3668 // Find the regions of the allocated chunk that can be promoted to large pages.
3669 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3670 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3671
3672 size_t lp_bytes = lp_end - lp_start;
3673
3674 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3675
3676 if (lp_bytes == 0) {
3677 // The mapped region doesn't even span the start and the end of a large page.
3678 // Fall back to allocate a non-special area.
3679 ::munmap(start, end - start);
3680 return NULL;
3681 }
3682
3683 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3684
3685 void* result;
3686
3687 // Commit small-paged leading area.
3688 if (start != lp_start) {
3689 result = ::mmap(start, lp_start - start, prot,
3690 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3691 -1, 0);
3692 if (result == MAP_FAILED) {
3693 ::munmap(lp_start, end - lp_start);
3694 return NULL;
3695 }
3696 }
3697
3698 // Commit large-paged area.
3699 result = ::mmap(lp_start, lp_bytes, prot,
3700 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3701 -1, 0);
3702 if (result == MAP_FAILED) {
3703 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3704 // If the mmap above fails, the large pages region will be unmapped and we
3705 // have regions before and after with small pages. Release these regions.
3706 //
3707 // | mapped | unmapped | mapped |
3708 // ^ ^ ^ ^
3709 // start lp_start lp_end end
3710 //
3711 ::munmap(start, lp_start - start);
3712 ::munmap(lp_end, end - lp_end);
3713 return NULL;
3714 }
3715
3716 // Commit small-paged trailing area.
3717 if (lp_end != end) {
3718 result = ::mmap(lp_end, end - lp_end, prot,
3719 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3720 -1, 0);
3721 if (result == MAP_FAILED) {
3722 ::munmap(start, lp_end - start);
3723 return NULL;
3724 }
3725 }
3726
3727 return start;
3728 }
3729
3730 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3731 size_t alignment,
3732 char* req_addr,
3733 bool exec) {
3734 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3735 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3736 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3737 assert(is_power_of_2(os::large_page_size()), "Must be");
3738 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3739
3740 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3741 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3742 } else {
3743 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3744 }
3745 }
3746
3747 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3748 char* req_addr, bool exec) {
3749 assert(UseLargePages, "only for large pages");
3750
3751 char* addr;
3752 if (UseSHM) {
3753 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3754 } else {
3755 assert(UseHugeTLBFS, "must be");
3756 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3757 }
3758
3759 if (addr != NULL) {
3760 if (UseNUMAInterleaving) {
3761 numa_make_global(addr, bytes);
3762 }
3763
3764 // The memory is committed
3765 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3766 }
3767
3768 return addr;
3769 }
3770
3771 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3772 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3773 return shmdt(base) == 0;
3774 }
3775
3776 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3777 return pd_release_memory(base, bytes);
3778 }
3779
3780 bool os::release_memory_special(char* base, size_t bytes) {
3781 bool res;
3782 if (MemTracker::tracking_level() > NMT_minimal) {
3783 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3784 res = os::Linux::release_memory_special_impl(base, bytes);
3785 if (res) {
3786 tkr.record((address)base, bytes);
3787 }
3788
3789 } else {
3790 res = os::Linux::release_memory_special_impl(base, bytes);
3791 }
3792 return res;
3793 }
3794
3795 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3796 assert(UseLargePages, "only for large pages");
3797 bool res;
3798
3799 if (UseSHM) {
3800 res = os::Linux::release_memory_special_shm(base, bytes);
3801 } else {
3802 assert(UseHugeTLBFS, "must be");
3803 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3804 }
3805 return res;
3806 }
3807
3808 size_t os::large_page_size() {
3809 return _large_page_size;
3810 }
3811
3812 // With SysV SHM the entire memory region must be allocated as shared
3813 // memory.
3814 // HugeTLBFS allows application to commit large page memory on demand.
3815 // However, when committing memory with HugeTLBFS fails, the region
3816 // that was supposed to be committed will lose the old reservation
3817 // and allow other threads to steal that memory region. Because of this
3818 // behavior we can't commit HugeTLBFS memory.
3819 bool os::can_commit_large_page_memory() {
3820 return UseTransparentHugePages;
3821 }
3822
3823 bool os::can_execute_large_page_memory() {
3824 return UseTransparentHugePages || UseHugeTLBFS;
3825 }
3826
3827 // Reserve memory at an arbitrary address, only if that area is
3828 // available (and not reserved for something else).
3829
3830 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3831 const int max_tries = 10;
3832 char* base[max_tries];
3833 size_t size[max_tries];
3834 const size_t gap = 0x000000;
3835
3836 // Assert only that the size is a multiple of the page size, since
3837 // that's all that mmap requires, and since that's all we really know
3838 // about at this low abstraction level. If we need higher alignment,
3839 // we can either pass an alignment to this method or verify alignment
3840 // in one of the methods further up the call chain. See bug 5044738.
3841 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3842
3843 // Repeatedly allocate blocks until the block is allocated at the
3844 // right spot.
3845
3846 // Linux mmap allows caller to pass an address as hint; give it a try first,
3847 // if kernel honors the hint then we can return immediately.
3848 char * addr = anon_mmap(requested_addr, bytes, false);
3849 if (addr == requested_addr) {
3850 return requested_addr;
3851 }
3852
3853 if (addr != NULL) {
3854 // mmap() is successful but it fails to reserve at the requested address
3855 anon_munmap(addr, bytes);
3856 }
3857
3858 int i;
3859 for (i = 0; i < max_tries; ++i) {
3860 base[i] = reserve_memory(bytes);
3861
3862 if (base[i] != NULL) {
3863 // Is this the block we wanted?
3864 if (base[i] == requested_addr) {
3865 size[i] = bytes;
3866 break;
3867 }
3868
3869 // Does this overlap the block we wanted? Give back the overlapped
3870 // parts and try again.
3871
3872 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3873 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3874 unmap_memory(base[i], top_overlap);
3875 base[i] += top_overlap;
3876 size[i] = bytes - top_overlap;
3877 } else {
3878 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3879 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3880 unmap_memory(requested_addr, bottom_overlap);
3881 size[i] = bytes - bottom_overlap;
3882 } else {
3883 size[i] = bytes;
3884 }
3885 }
3886 }
3887 }
3888
3889 // Give back the unused reserved pieces.
3890
3891 for (int j = 0; j < i; ++j) {
3892 if (base[j] != NULL) {
3893 unmap_memory(base[j], size[j]);
3894 }
3895 }
3896
3897 if (i < max_tries) {
3898 return requested_addr;
3899 } else {
3900 return NULL;
3901 }
3902 }
3903
3904 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3905 return ::read(fd, buf, nBytes);
3906 }
3907
3908 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3909 return ::pread(fd, buf, nBytes, offset);
3910 }
3911
3912 // Short sleep, direct OS call.
3913 //
3914 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3915 // sched_yield(2) will actually give up the CPU:
3916 //
3917 // * Alone on this pariticular CPU, keeps running.
3918 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3919 // (pre 2.6.39).
3920 //
3921 // So calling this with 0 is an alternative.
3922 //
3923 void os::naked_short_sleep(jlong ms) {
3924 struct timespec req;
3925
3926 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3927 req.tv_sec = 0;
3928 if (ms > 0) {
3929 req.tv_nsec = (ms % 1000) * 1000000;
3930 } else {
3931 req.tv_nsec = 1;
3932 }
3933
3934 nanosleep(&req, NULL);
3935
3936 return;
3937 }
3938
3939 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3940 void os::infinite_sleep() {
3941 while (true) { // sleep forever ...
3942 ::sleep(100); // ... 100 seconds at a time
3943 }
3944 }
3945
3946 // Used to convert frequent JVM_Yield() to nops
3947 bool os::dont_yield() {
3948 return DontYieldALot;
3949 }
3950
3951 void os::naked_yield() {
3952 sched_yield();
3953 }
3954
3955 ////////////////////////////////////////////////////////////////////////////////
3956 // thread priority support
3957
3958 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3959 // only supports dynamic priority, static priority must be zero. For real-time
3960 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3961 // However, for large multi-threaded applications, SCHED_RR is not only slower
3962 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3963 // of 5 runs - Sep 2005).
3964 //
3965 // The following code actually changes the niceness of kernel-thread/LWP. It
3966 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3967 // not the entire user process, and user level threads are 1:1 mapped to kernel
3968 // threads. It has always been the case, but could change in the future. For
3969 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3970 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3971
3972 int os::java_to_os_priority[CriticalPriority + 1] = {
3973 19, // 0 Entry should never be used
3974
3975 4, // 1 MinPriority
3976 3, // 2
3977 2, // 3
3978
3979 1, // 4
3980 0, // 5 NormPriority
3981 -1, // 6
3982
3983 -2, // 7
3984 -3, // 8
3985 -4, // 9 NearMaxPriority
3986
3987 -5, // 10 MaxPriority
3988
3989 -5 // 11 CriticalPriority
3990 };
3991
3992 static int prio_init() {
3993 if (ThreadPriorityPolicy == 1) {
3994 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3995 // if effective uid is not root. Perhaps, a more elegant way of doing
3996 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3997 if (geteuid() != 0) {
3998 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3999 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
4000 }
4001 ThreadPriorityPolicy = 0;
4002 }
4003 }
4004 if (UseCriticalJavaThreadPriority) {
4005 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4006 }
4007 return 0;
4008 }
4009
4010 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4011 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
4012
4013 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4014 return (ret == 0) ? OS_OK : OS_ERR;
4015 }
4016
4017 OSReturn os::get_native_priority(const Thread* const thread,
4018 int *priority_ptr) {
4019 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
4020 *priority_ptr = java_to_os_priority[NormPriority];
4021 return OS_OK;
4022 }
4023
4024 errno = 0;
4025 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4026 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4027 }
4028
4029 // Hint to the underlying OS that a task switch would not be good.
4030 // Void return because it's a hint and can fail.
4031 void os::hint_no_preempt() {}
4032
4033 ////////////////////////////////////////////////////////////////////////////////
4034 // suspend/resume support
4035
4036 // the low-level signal-based suspend/resume support is a remnant from the
4037 // old VM-suspension that used to be for java-suspension, safepoints etc,
4038 // within hotspot. Now there is a single use-case for this:
4039 // - calling get_thread_pc() on the VMThread by the flat-profiler task
4040 // that runs in the watcher thread.
4041 // The remaining code is greatly simplified from the more general suspension
4042 // code that used to be used.
4043 //
4044 // The protocol is quite simple:
4045 // - suspend:
4046 // - sends a signal to the target thread
4047 // - polls the suspend state of the osthread using a yield loop
4048 // - target thread signal handler (SR_handler) sets suspend state
4049 // and blocks in sigsuspend until continued
4050 // - resume:
4051 // - sets target osthread state to continue
4052 // - sends signal to end the sigsuspend loop in the SR_handler
4053 //
4054 // Note that the SR_lock plays no role in this suspend/resume protocol,
4055 // but is checked for NULL in SR_handler as a thread termination indicator.
4056
4057 static void resume_clear_context(OSThread *osthread) {
4058 osthread->set_ucontext(NULL);
4059 osthread->set_siginfo(NULL);
4060 }
4061
4062 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4063 ucontext_t* context) {
4064 osthread->set_ucontext(context);
4065 osthread->set_siginfo(siginfo);
4066 }
4067
4068 // Handler function invoked when a thread's execution is suspended or
4069 // resumed. We have to be careful that only async-safe functions are
4070 // called here (Note: most pthread functions are not async safe and
4071 // should be avoided.)
4072 //
4073 // Note: sigwait() is a more natural fit than sigsuspend() from an
4074 // interface point of view, but sigwait() prevents the signal hander
4075 // from being run. libpthread would get very confused by not having
4076 // its signal handlers run and prevents sigwait()'s use with the
4077 // mutex granting granting signal.
4078 //
4079 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4080 //
4081 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4082 // Save and restore errno to avoid confusing native code with EINTR
4083 // after sigsuspend.
4084 int old_errno = errno;
4085
4086 Thread* thread = Thread::current_or_null_safe();
4087 assert(thread != NULL, "Missing current thread in SR_handler");
4088
4089 // On some systems we have seen signal delivery get "stuck" until the signal
4090 // mask is changed as part of thread termination. Check that the current thread
4091 // has not already terminated (via SR_lock()) - else the following assertion
4092 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4093 // destructor has completed.
4094
4095 if (thread->SR_lock() == NULL) {
4096 return;
4097 }
4098
4099 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4100
4101 OSThread* osthread = thread->osthread();
4102
4103 os::SuspendResume::State current = osthread->sr.state();
4104 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4105 suspend_save_context(osthread, siginfo, context);
4106
4107 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4108 os::SuspendResume::State state = osthread->sr.suspended();
4109 if (state == os::SuspendResume::SR_SUSPENDED) {
4110 sigset_t suspend_set; // signals for sigsuspend()
4111 sigemptyset(&suspend_set);
4112 // get current set of blocked signals and unblock resume signal
4113 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4114 sigdelset(&suspend_set, SR_signum);
4115
4116 sr_semaphore.signal();
4117 // wait here until we are resumed
4118 while (1) {
4119 sigsuspend(&suspend_set);
4120
4121 os::SuspendResume::State result = osthread->sr.running();
4122 if (result == os::SuspendResume::SR_RUNNING) {
4123 sr_semaphore.signal();
4124 break;
4125 }
4126 }
4127
4128 } else if (state == os::SuspendResume::SR_RUNNING) {
4129 // request was cancelled, continue
4130 } else {
4131 ShouldNotReachHere();
4132 }
4133
4134 resume_clear_context(osthread);
4135 } else if (current == os::SuspendResume::SR_RUNNING) {
4136 // request was cancelled, continue
4137 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4138 // ignore
4139 } else {
4140 // ignore
4141 }
4142
4143 errno = old_errno;
4144 }
4145
4146 static int SR_initialize() {
4147 struct sigaction act;
4148 char *s;
4149
4150 // Get signal number to use for suspend/resume
4151 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4152 int sig = ::strtol(s, 0, 10);
4153 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4154 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4155 SR_signum = sig;
4156 } else {
4157 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4158 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4159 }
4160 }
4161
4162 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4163 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4164
4165 sigemptyset(&SR_sigset);
4166 sigaddset(&SR_sigset, SR_signum);
4167
4168 // Set up signal handler for suspend/resume
4169 act.sa_flags = SA_RESTART|SA_SIGINFO;
4170 act.sa_handler = (void (*)(int)) SR_handler;
4171
4172 // SR_signum is blocked by default.
4173 // 4528190 - We also need to block pthread restart signal (32 on all
4174 // supported Linux platforms). Note that LinuxThreads need to block
4175 // this signal for all threads to work properly. So we don't have
4176 // to use hard-coded signal number when setting up the mask.
4177 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4178
4179 if (sigaction(SR_signum, &act, 0) == -1) {
4180 return -1;
4181 }
4182
4183 // Save signal flag
4184 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4185 return 0;
4186 }
4187
4188 static int sr_notify(OSThread* osthread) {
4189 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4190 assert_status(status == 0, status, "pthread_kill");
4191 return status;
4192 }
4193
4194 // "Randomly" selected value for how long we want to spin
4195 // before bailing out on suspending a thread, also how often
4196 // we send a signal to a thread we want to resume
4197 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4198 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4199
4200 // returns true on success and false on error - really an error is fatal
4201 // but this seems the normal response to library errors
4202 static bool do_suspend(OSThread* osthread) {
4203 assert(osthread->sr.is_running(), "thread should be running");
4204 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4205
4206 // mark as suspended and send signal
4207 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4208 // failed to switch, state wasn't running?
4209 ShouldNotReachHere();
4210 return false;
4211 }
4212
4213 if (sr_notify(osthread) != 0) {
4214 ShouldNotReachHere();
4215 }
4216
4217 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4218 while (true) {
4219 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4220 break;
4221 } else {
4222 // timeout
4223 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4224 if (cancelled == os::SuspendResume::SR_RUNNING) {
4225 return false;
4226 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4227 // make sure that we consume the signal on the semaphore as well
4228 sr_semaphore.wait();
4229 break;
4230 } else {
4231 ShouldNotReachHere();
4232 return false;
4233 }
4234 }
4235 }
4236
4237 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4238 return true;
4239 }
4240
4241 static void do_resume(OSThread* osthread) {
4242 assert(osthread->sr.is_suspended(), "thread should be suspended");
4243 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4244
4245 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4246 // failed to switch to WAKEUP_REQUEST
4247 ShouldNotReachHere();
4248 return;
4249 }
4250
4251 while (true) {
4252 if (sr_notify(osthread) == 0) {
4253 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4254 if (osthread->sr.is_running()) {
4255 return;
4256 }
4257 }
4258 } else {
4259 ShouldNotReachHere();
4260 }
4261 }
4262
4263 guarantee(osthread->sr.is_running(), "Must be running!");
4264 }
4265
4266 ///////////////////////////////////////////////////////////////////////////////////
4267 // signal handling (except suspend/resume)
4268
4269 // This routine may be used by user applications as a "hook" to catch signals.
4270 // The user-defined signal handler must pass unrecognized signals to this
4271 // routine, and if it returns true (non-zero), then the signal handler must
4272 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4273 // routine will never retun false (zero), but instead will execute a VM panic
4274 // routine kill the process.
4275 //
4276 // If this routine returns false, it is OK to call it again. This allows
4277 // the user-defined signal handler to perform checks either before or after
4278 // the VM performs its own checks. Naturally, the user code would be making
4279 // a serious error if it tried to handle an exception (such as a null check
4280 // or breakpoint) that the VM was generating for its own correct operation.
4281 //
4282 // This routine may recognize any of the following kinds of signals:
4283 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4284 // It should be consulted by handlers for any of those signals.
4285 //
4286 // The caller of this routine must pass in the three arguments supplied
4287 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4288 // field of the structure passed to sigaction(). This routine assumes that
4289 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4290 //
4291 // Note that the VM will print warnings if it detects conflicting signal
4292 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4293 //
4294 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4295 siginfo_t* siginfo,
4296 void* ucontext,
4297 int abort_if_unrecognized);
4298
4299 void signalHandler(int sig, siginfo_t* info, void* uc) {
4300 assert(info != NULL && uc != NULL, "it must be old kernel");
4301 int orig_errno = errno; // Preserve errno value over signal handler.
4302 JVM_handle_linux_signal(sig, info, uc, true);
4303 errno = orig_errno;
4304 }
4305
4306
4307 // This boolean allows users to forward their own non-matching signals
4308 // to JVM_handle_linux_signal, harmlessly.
4309 bool os::Linux::signal_handlers_are_installed = false;
4310
4311 // For signal-chaining
4312 struct sigaction sigact[NSIG];
4313 uint64_t sigs = 0;
4314 #if (64 < NSIG-1)
4315 #error "Not all signals can be encoded in sigs. Adapt its type!"
4316 #endif
4317 bool os::Linux::libjsig_is_loaded = false;
4318 typedef struct sigaction *(*get_signal_t)(int);
4319 get_signal_t os::Linux::get_signal_action = NULL;
4320
4321 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4322 struct sigaction *actp = NULL;
4323
4324 if (libjsig_is_loaded) {
4325 // Retrieve the old signal handler from libjsig
4326 actp = (*get_signal_action)(sig);
4327 }
4328 if (actp == NULL) {
4329 // Retrieve the preinstalled signal handler from jvm
4330 actp = get_preinstalled_handler(sig);
4331 }
4332
4333 return actp;
4334 }
4335
4336 static bool call_chained_handler(struct sigaction *actp, int sig,
4337 siginfo_t *siginfo, void *context) {
4338 // Call the old signal handler
4339 if (actp->sa_handler == SIG_DFL) {
4340 // It's more reasonable to let jvm treat it as an unexpected exception
4341 // instead of taking the default action.
4342 return false;
4343 } else if (actp->sa_handler != SIG_IGN) {
4344 if ((actp->sa_flags & SA_NODEFER) == 0) {
4345 // automaticlly block the signal
4346 sigaddset(&(actp->sa_mask), sig);
4347 }
4348
4349 sa_handler_t hand = NULL;
4350 sa_sigaction_t sa = NULL;
4351 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4352 // retrieve the chained handler
4353 if (siginfo_flag_set) {
4354 sa = actp->sa_sigaction;
4355 } else {
4356 hand = actp->sa_handler;
4357 }
4358
4359 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4360 actp->sa_handler = SIG_DFL;
4361 }
4362
4363 // try to honor the signal mask
4364 sigset_t oset;
4365 sigemptyset(&oset);
4366 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4367
4368 // call into the chained handler
4369 if (siginfo_flag_set) {
4370 (*sa)(sig, siginfo, context);
4371 } else {
4372 (*hand)(sig);
4373 }
4374
4375 // restore the signal mask
4376 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4377 }
4378 // Tell jvm's signal handler the signal is taken care of.
4379 return true;
4380 }
4381
4382 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4383 bool chained = false;
4384 // signal-chaining
4385 if (UseSignalChaining) {
4386 struct sigaction *actp = get_chained_signal_action(sig);
4387 if (actp != NULL) {
4388 chained = call_chained_handler(actp, sig, siginfo, context);
4389 }
4390 }
4391 return chained;
4392 }
4393
4394 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4395 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4396 return &sigact[sig];
4397 }
4398 return NULL;
4399 }
4400
4401 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4402 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4403 sigact[sig] = oldAct;
4404 sigs |= (uint64_t)1 << (sig-1);
4405 }
4406
4407 // for diagnostic
4408 int sigflags[NSIG];
4409
4410 int os::Linux::get_our_sigflags(int sig) {
4411 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4412 return sigflags[sig];
4413 }
4414
4415 void os::Linux::set_our_sigflags(int sig, int flags) {
4416 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4417 if (sig > 0 && sig < NSIG) {
4418 sigflags[sig] = flags;
4419 }
4420 }
4421
4422 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4423 // Check for overwrite.
4424 struct sigaction oldAct;
4425 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4426
4427 void* oldhand = oldAct.sa_sigaction
4428 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4429 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4430 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4431 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4432 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4433 if (AllowUserSignalHandlers || !set_installed) {
4434 // Do not overwrite; user takes responsibility to forward to us.
4435 return;
4436 } else if (UseSignalChaining) {
4437 // save the old handler in jvm
4438 save_preinstalled_handler(sig, oldAct);
4439 // libjsig also interposes the sigaction() call below and saves the
4440 // old sigaction on it own.
4441 } else {
4442 fatal("Encountered unexpected pre-existing sigaction handler "
4443 "%#lx for signal %d.", (long)oldhand, sig);
4444 }
4445 }
4446
4447 struct sigaction sigAct;
4448 sigfillset(&(sigAct.sa_mask));
4449 sigAct.sa_handler = SIG_DFL;
4450 if (!set_installed) {
4451 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4452 } else {
4453 sigAct.sa_sigaction = signalHandler;
4454 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4455 }
4456 // Save flags, which are set by ours
4457 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4458 sigflags[sig] = sigAct.sa_flags;
4459
4460 int ret = sigaction(sig, &sigAct, &oldAct);
4461 assert(ret == 0, "check");
4462
4463 void* oldhand2 = oldAct.sa_sigaction
4464 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4465 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4466 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4467 }
4468
4469 // install signal handlers for signals that HotSpot needs to
4470 // handle in order to support Java-level exception handling.
4471
4472 void os::Linux::install_signal_handlers() {
4473 if (!signal_handlers_are_installed) {
4474 signal_handlers_are_installed = true;
4475
4476 // signal-chaining
4477 typedef void (*signal_setting_t)();
4478 signal_setting_t begin_signal_setting = NULL;
4479 signal_setting_t end_signal_setting = NULL;
4480 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4481 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4482 if (begin_signal_setting != NULL) {
4483 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4484 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4485 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4486 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4487 libjsig_is_loaded = true;
4488 assert(UseSignalChaining, "should enable signal-chaining");
4489 }
4490 if (libjsig_is_loaded) {
4491 // Tell libjsig jvm is setting signal handlers
4492 (*begin_signal_setting)();
4493 }
4494
4495 set_signal_handler(SIGSEGV, true);
4496 set_signal_handler(SIGPIPE, true);
4497 set_signal_handler(SIGBUS, true);
4498 set_signal_handler(SIGILL, true);
4499 set_signal_handler(SIGFPE, true);
4500 #if defined(PPC64)
4501 set_signal_handler(SIGTRAP, true);
4502 #endif
4503 set_signal_handler(SIGXFSZ, true);
4504
4505 if (libjsig_is_loaded) {
4506 // Tell libjsig jvm finishes setting signal handlers
4507 (*end_signal_setting)();
4508 }
4509
4510 // We don't activate signal checker if libjsig is in place, we trust ourselves
4511 // and if UserSignalHandler is installed all bets are off.
4512 // Log that signal checking is off only if -verbose:jni is specified.
4513 if (CheckJNICalls) {
4514 if (libjsig_is_loaded) {
4515 if (PrintJNIResolving) {
4516 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4517 }
4518 check_signals = false;
4519 }
4520 if (AllowUserSignalHandlers) {
4521 if (PrintJNIResolving) {
4522 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4523 }
4524 check_signals = false;
4525 }
4526 }
4527 }
4528 }
4529
4530 // This is the fastest way to get thread cpu time on Linux.
4531 // Returns cpu time (user+sys) for any thread, not only for current.
4532 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4533 // It might work on 2.6.10+ with a special kernel/glibc patch.
4534 // For reference, please, see IEEE Std 1003.1-2004:
4535 // http://www.unix.org/single_unix_specification
4536
4537 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4538 struct timespec tp;
4539 int rc = os::Linux::clock_gettime(clockid, &tp);
4540 assert(rc == 0, "clock_gettime is expected to return 0 code");
4541
4542 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4543 }
4544
4545 void os::Linux::initialize_os_info() {
4546 assert(_os_version == 0, "OS info already initialized");
4547
4548 struct utsname _uname;
4549
4550 uint32_t major;
4551 uint32_t minor;
4552 uint32_t fix;
4553
4554 int rc;
4555
4556 // Kernel version is unknown if
4557 // verification below fails.
4558 _os_version = 0x01000000;
4559
4560 rc = uname(&_uname);
4561 if (rc != -1) {
4562
4563 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4564 if (rc == 3) {
4565
4566 if (major < 256 && minor < 256 && fix < 256) {
4567 // Kernel version format is as expected,
4568 // set it overriding unknown state.
4569 _os_version = (major << 16) |
4570 (minor << 8 ) |
4571 (fix << 0 ) ;
4572 }
4573 }
4574 }
4575 }
4576
4577 uint32_t os::Linux::os_version() {
4578 assert(_os_version != 0, "not initialized");
4579 return _os_version & 0x00FFFFFF;
4580 }
4581
4582 bool os::Linux::os_version_is_known() {
4583 assert(_os_version != 0, "not initialized");
4584 return _os_version & 0x01000000 ? false : true;
4585 }
4586
4587 /////
4588 // glibc on Linux platform uses non-documented flag
4589 // to indicate, that some special sort of signal
4590 // trampoline is used.
4591 // We will never set this flag, and we should
4592 // ignore this flag in our diagnostic
4593 #ifdef SIGNIFICANT_SIGNAL_MASK
4594 #undef SIGNIFICANT_SIGNAL_MASK
4595 #endif
4596 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4597
4598 static const char* get_signal_handler_name(address handler,
4599 char* buf, int buflen) {
4600 int offset = 0;
4601 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4602 if (found) {
4603 // skip directory names
4604 const char *p1, *p2;
4605 p1 = buf;
4606 size_t len = strlen(os::file_separator());
4607 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4608 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4609 } else {
4610 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4611 }
4612 return buf;
4613 }
4614
4615 static void print_signal_handler(outputStream* st, int sig,
4616 char* buf, size_t buflen) {
4617 struct sigaction sa;
4618
4619 sigaction(sig, NULL, &sa);
4620
4621 // See comment for SIGNIFICANT_SIGNAL_MASK define
4622 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4623
4624 st->print("%s: ", os::exception_name(sig, buf, buflen));
4625
4626 address handler = (sa.sa_flags & SA_SIGINFO)
4627 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4628 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4629
4630 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4631 st->print("SIG_DFL");
4632 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4633 st->print("SIG_IGN");
4634 } else {
4635 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4636 }
4637
4638 st->print(", sa_mask[0]=");
4639 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4640
4641 address rh = VMError::get_resetted_sighandler(sig);
4642 // May be, handler was resetted by VMError?
4643 if (rh != NULL) {
4644 handler = rh;
4645 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4646 }
4647
4648 st->print(", sa_flags=");
4649 os::Posix::print_sa_flags(st, sa.sa_flags);
4650
4651 // Check: is it our handler?
4652 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4653 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4654 // It is our signal handler
4655 // check for flags, reset system-used one!
4656 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4657 st->print(
4658 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4659 os::Linux::get_our_sigflags(sig));
4660 }
4661 }
4662 st->cr();
4663 }
4664
4665
4666 #define DO_SIGNAL_CHECK(sig) \
4667 do { \
4668 if (!sigismember(&check_signal_done, sig)) { \
4669 os::Linux::check_signal_handler(sig); \
4670 } \
4671 } while (0)
4672
4673 // This method is a periodic task to check for misbehaving JNI applications
4674 // under CheckJNI, we can add any periodic checks here
4675
4676 void os::run_periodic_checks() {
4677 if (check_signals == false) return;
4678
4679 // SEGV and BUS if overridden could potentially prevent
4680 // generation of hs*.log in the event of a crash, debugging
4681 // such a case can be very challenging, so we absolutely
4682 // check the following for a good measure:
4683 DO_SIGNAL_CHECK(SIGSEGV);
4684 DO_SIGNAL_CHECK(SIGILL);
4685 DO_SIGNAL_CHECK(SIGFPE);
4686 DO_SIGNAL_CHECK(SIGBUS);
4687 DO_SIGNAL_CHECK(SIGPIPE);
4688 DO_SIGNAL_CHECK(SIGXFSZ);
4689 #if defined(PPC64)
4690 DO_SIGNAL_CHECK(SIGTRAP);
4691 #endif
4692
4693 // ReduceSignalUsage allows the user to override these handlers
4694 // see comments at the very top and jvm_solaris.h
4695 if (!ReduceSignalUsage) {
4696 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4697 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4698 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4699 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4700 }
4701
4702 DO_SIGNAL_CHECK(SR_signum);
4703 }
4704
4705 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4706
4707 static os_sigaction_t os_sigaction = NULL;
4708
4709 void os::Linux::check_signal_handler(int sig) {
4710 char buf[O_BUFLEN];
4711 address jvmHandler = NULL;
4712
4713
4714 struct sigaction act;
4715 if (os_sigaction == NULL) {
4716 // only trust the default sigaction, in case it has been interposed
4717 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4718 if (os_sigaction == NULL) return;
4719 }
4720
4721 os_sigaction(sig, (struct sigaction*)NULL, &act);
4722
4723
4724 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4725
4726 address thisHandler = (act.sa_flags & SA_SIGINFO)
4727 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4728 : CAST_FROM_FN_PTR(address, act.sa_handler);
4729
4730
4731 switch (sig) {
4732 case SIGSEGV:
4733 case SIGBUS:
4734 case SIGFPE:
4735 case SIGPIPE:
4736 case SIGILL:
4737 case SIGXFSZ:
4738 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4739 break;
4740
4741 case SHUTDOWN1_SIGNAL:
4742 case SHUTDOWN2_SIGNAL:
4743 case SHUTDOWN3_SIGNAL:
4744 case BREAK_SIGNAL:
4745 jvmHandler = (address)user_handler();
4746 break;
4747
4748 default:
4749 if (sig == SR_signum) {
4750 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4751 } else {
4752 return;
4753 }
4754 break;
4755 }
4756
4757 if (thisHandler != jvmHandler) {
4758 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4759 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4760 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4761 // No need to check this sig any longer
4762 sigaddset(&check_signal_done, sig);
4763 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4764 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4765 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4766 exception_name(sig, buf, O_BUFLEN));
4767 }
4768 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4769 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4770 tty->print("expected:");
4771 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4772 tty->cr();
4773 tty->print(" found:");
4774 os::Posix::print_sa_flags(tty, act.sa_flags);
4775 tty->cr();
4776 // No need to check this sig any longer
4777 sigaddset(&check_signal_done, sig);
4778 }
4779
4780 // Dump all the signal
4781 if (sigismember(&check_signal_done, sig)) {
4782 print_signal_handlers(tty, buf, O_BUFLEN);
4783 }
4784 }
4785
4786 extern void report_error(char* file_name, int line_no, char* title,
4787 char* format, ...);
4788
4789 // this is called _before_ the most of global arguments have been parsed
4790 void os::init(void) {
4791 char dummy; // used to get a guess on initial stack address
4792 // first_hrtime = gethrtime();
4793
4794 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4795
4796 init_random(1234567);
4797
4798 ThreadCritical::initialize();
4799
4800 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4801 if (Linux::page_size() == -1) {
4802 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4803 os::strerror(errno));
4804 }
4805 init_page_sizes((size_t) Linux::page_size());
4806
4807 Linux::initialize_system_info();
4808
4809 Linux::initialize_os_info();
4810
4811 // main_thread points to the aboriginal thread
4812 Linux::_main_thread = pthread_self();
4813
4814 Linux::clock_init();
4815 initial_time_count = javaTimeNanos();
4816
4817 // retrieve entry point for pthread_setname_np
4818 Linux::_pthread_setname_np =
4819 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4820
4821 os::Posix::init();
4822 }
4823
4824 // To install functions for atexit system call
4825 extern "C" {
4826 static void perfMemory_exit_helper() {
4827 perfMemory_exit();
4828 }
4829 }
4830
4831 // this is called _after_ the global arguments have been parsed
4832 jint os::init_2(void) {
4833
4834 os::Posix::init_2();
4835
4836 Linux::fast_thread_clock_init();
4837
4838 // Allocate a single page and mark it as readable for safepoint polling
4839 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4840 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4841
4842 os::set_polling_page(polling_page);
4843 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4844
4845 if (!UseMembar) {
4846 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4847 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4848 os::set_memory_serialize_page(mem_serialize_page);
4849 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4850 }
4851
4852 // initialize suspend/resume support - must do this before signal_sets_init()
4853 if (SR_initialize() != 0) {
4854 perror("SR_initialize failed");
4855 return JNI_ERR;
4856 }
4857
4858 Linux::signal_sets_init();
4859 Linux::install_signal_handlers();
4860
4861 // Check and sets minimum stack sizes against command line options
4862 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
4863 return JNI_ERR;
4864 }
4865 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4866
4867 #if defined(IA32)
4868 workaround_expand_exec_shield_cs_limit();
4869 #endif
4870
4871 Linux::libpthread_init();
4872 log_info(os)("HotSpot is running with %s, %s",
4873 Linux::glibc_version(), Linux::libpthread_version());
4874
4875 if (UseNUMA) {
4876 if (!Linux::libnuma_init()) {
4877 UseNUMA = false;
4878 } else {
4879 if ((Linux::numa_max_node() < 1)) {
4880 // There's only one node(they start from 0), disable NUMA.
4881 UseNUMA = false;
4882 }
4883 }
4884 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4885 // we can make the adaptive lgrp chunk resizing work. If the user specified
4886 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4887 // disable adaptive resizing.
4888 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4889 if (FLAG_IS_DEFAULT(UseNUMA)) {
4890 UseNUMA = false;
4891 } else {
4892 if (FLAG_IS_DEFAULT(UseLargePages) &&
4893 FLAG_IS_DEFAULT(UseSHM) &&
4894 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4895 UseLargePages = false;
4896 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4897 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4898 UseAdaptiveSizePolicy = false;
4899 UseAdaptiveNUMAChunkSizing = false;
4900 }
4901 }
4902 }
4903 if (!UseNUMA && ForceNUMA) {
4904 UseNUMA = true;
4905 }
4906 }
4907
4908 if (MaxFDLimit) {
4909 // set the number of file descriptors to max. print out error
4910 // if getrlimit/setrlimit fails but continue regardless.
4911 struct rlimit nbr_files;
4912 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4913 if (status != 0) {
4914 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4915 } else {
4916 nbr_files.rlim_cur = nbr_files.rlim_max;
4917 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4918 if (status != 0) {
4919 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4920 }
4921 }
4922 }
4923
4924 // Initialize lock used to serialize thread creation (see os::create_thread)
4925 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4926
4927 // at-exit methods are called in the reverse order of their registration.
4928 // atexit functions are called on return from main or as a result of a
4929 // call to exit(3C). There can be only 32 of these functions registered
4930 // and atexit() does not set errno.
4931
4932 if (PerfAllowAtExitRegistration) {
4933 // only register atexit functions if PerfAllowAtExitRegistration is set.
4934 // atexit functions can be delayed until process exit time, which
4935 // can be problematic for embedded VM situations. Embedded VMs should
4936 // call DestroyJavaVM() to assure that VM resources are released.
4937
4938 // note: perfMemory_exit_helper atexit function may be removed in
4939 // the future if the appropriate cleanup code can be added to the
4940 // VM_Exit VMOperation's doit method.
4941 if (atexit(perfMemory_exit_helper) != 0) {
4942 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4943 }
4944 }
4945
4946 // initialize thread priority policy
4947 prio_init();
4948
4949 return JNI_OK;
4950 }
4951
4952 // Mark the polling page as unreadable
4953 void os::make_polling_page_unreadable(void) {
4954 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4955 fatal("Could not disable polling page");
4956 }
4957 }
4958
4959 // Mark the polling page as readable
4960 void os::make_polling_page_readable(void) {
4961 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4962 fatal("Could not enable polling page");
4963 }
4964 }
4965
4966 // older glibc versions don't have this macro (which expands to
4967 // an optimized bit-counting function) so we have to roll our own
4968 #ifndef CPU_COUNT
4969
4970 static int _cpu_count(const cpu_set_t* cpus) {
4971 int count = 0;
4972 // only look up to the number of configured processors
4973 for (int i = 0; i < os::processor_count(); i++) {
4974 if (CPU_ISSET(i, cpus)) {
4975 count++;
4976 }
4977 }
4978 return count;
4979 }
4980
4981 #define CPU_COUNT(cpus) _cpu_count(cpus)
4982
4983 #endif // CPU_COUNT
4984
4985 // Get the current number of available processors for this process.
4986 // This value can change at any time during a process's lifetime.
4987 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4988 // If it appears there may be more than 1024 processors then we do a
4989 // dynamic check - see 6515172 for details.
4990 // If anything goes wrong we fallback to returning the number of online
4991 // processors - which can be greater than the number available to the process.
4992 int os::active_processor_count() {
4993 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4994 cpu_set_t* cpus_p = &cpus;
4995 int cpus_size = sizeof(cpu_set_t);
4996
4997 int configured_cpus = processor_count(); // upper bound on available cpus
4998 int cpu_count = 0;
4999
5000 // old build platforms may not support dynamic cpu sets
5001 #ifdef CPU_ALLOC
5002
5003 // To enable easy testing of the dynamic path on different platforms we
5004 // introduce a diagnostic flag: UseCpuAllocPath
5005 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
5006 // kernel may use a mask bigger than cpu_set_t
5007 log_trace(os)("active_processor_count: using dynamic path %s"
5008 "- configured processors: %d",
5009 UseCpuAllocPath ? "(forced) " : "",
5010 configured_cpus);
5011 cpus_p = CPU_ALLOC(configured_cpus);
5012 if (cpus_p != NULL) {
5013 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
5014 // zero it just to be safe
5015 CPU_ZERO_S(cpus_size, cpus_p);
5016 }
5017 else {
5018 // failed to allocate so fallback to online cpus
5019 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5020 log_trace(os)("active_processor_count: "
5021 "CPU_ALLOC failed (%s) - using "
5022 "online processor count: %d",
5023 os::strerror(errno), online_cpus);
5024 return online_cpus;
5025 }
5026 }
5027 else {
5028 log_trace(os)("active_processor_count: using static path - configured processors: %d",
5029 configured_cpus);
5030 }
5031 #else // CPU_ALLOC
5032 // these stubs won't be executed
5033 #define CPU_COUNT_S(size, cpus) -1
5034 #define CPU_FREE(cpus)
5035
5036 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
5037 configured_cpus);
5038 #endif // CPU_ALLOC
5039
5040 // pid 0 means the current thread - which we have to assume represents the process
5041 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
5042 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5043 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5044 }
5045 else {
5046 cpu_count = CPU_COUNT(cpus_p);
5047 }
5048 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5049 }
5050 else {
5051 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5052 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5053 "which may exceed available processors", os::strerror(errno), cpu_count);
5054 }
5055
5056 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5057 CPU_FREE(cpus_p);
5058 }
5059
5060 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
5061 return cpu_count;
5062 }
5063
5064 void os::set_native_thread_name(const char *name) {
5065 if (Linux::_pthread_setname_np) {
5066 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5067 snprintf(buf, sizeof(buf), "%s", name);
5068 buf[sizeof(buf) - 1] = '\0';
5069 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5070 // ERANGE should not happen; all other errors should just be ignored.
5071 assert(rc != ERANGE, "pthread_setname_np failed");
5072 }
5073 }
5074
5075 bool os::distribute_processes(uint length, uint* distribution) {
5076 // Not yet implemented.
5077 return false;
5078 }
5079
5080 bool os::bind_to_processor(uint processor_id) {
5081 // Not yet implemented.
5082 return false;
5083 }
5084
5085 ///
5086
5087 void os::SuspendedThreadTask::internal_do_task() {
5088 if (do_suspend(_thread->osthread())) {
5089 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5090 do_task(context);
5091 do_resume(_thread->osthread());
5092 }
5093 }
5094
5095 class PcFetcher : public os::SuspendedThreadTask {
5096 public:
5097 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5098 ExtendedPC result();
5099 protected:
5100 void do_task(const os::SuspendedThreadTaskContext& context);
5101 private:
5102 ExtendedPC _epc;
5103 };
5104
5105 ExtendedPC PcFetcher::result() {
5106 guarantee(is_done(), "task is not done yet.");
5107 return _epc;
5108 }
5109
5110 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5111 Thread* thread = context.thread();
5112 OSThread* osthread = thread->osthread();
5113 if (osthread->ucontext() != NULL) {
5114 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5115 } else {
5116 // NULL context is unexpected, double-check this is the VMThread
5117 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5118 }
5119 }
5120
5121 // Suspends the target using the signal mechanism and then grabs the PC before
5122 // resuming the target. Used by the flat-profiler only
5123 ExtendedPC os::get_thread_pc(Thread* thread) {
5124 // Make sure that it is called by the watcher for the VMThread
5125 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5126 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5127
5128 PcFetcher fetcher(thread);
5129 fetcher.run();
5130 return fetcher.result();
5131 }
5132
5133 ////////////////////////////////////////////////////////////////////////////////
5134 // debug support
5135
5136 bool os::find(address addr, outputStream* st) {
5137 Dl_info dlinfo;
5138 memset(&dlinfo, 0, sizeof(dlinfo));
5139 if (dladdr(addr, &dlinfo) != 0) {
5140 st->print(PTR_FORMAT ": ", p2i(addr));
5141 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5142 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5143 p2i(addr) - p2i(dlinfo.dli_saddr));
5144 } else if (dlinfo.dli_fbase != NULL) {
5145 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5146 } else {
5147 st->print("<absolute address>");
5148 }
5149 if (dlinfo.dli_fname != NULL) {
5150 st->print(" in %s", dlinfo.dli_fname);
5151 }
5152 if (dlinfo.dli_fbase != NULL) {
5153 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5154 }
5155 st->cr();
5156
5157 if (Verbose) {
5158 // decode some bytes around the PC
5159 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5160 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5161 address lowest = (address) dlinfo.dli_sname;
5162 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5163 if (begin < lowest) begin = lowest;
5164 Dl_info dlinfo2;
5165 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5166 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5167 end = (address) dlinfo2.dli_saddr;
5168 }
5169 Disassembler::decode(begin, end, st);
5170 }
5171 return true;
5172 }
5173 return false;
5174 }
5175
5176 ////////////////////////////////////////////////////////////////////////////////
5177 // misc
5178
5179 // This does not do anything on Linux. This is basically a hook for being
5180 // able to use structured exception handling (thread-local exception filters)
5181 // on, e.g., Win32.
5182 void
5183 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5184 JavaCallArguments* args, Thread* thread) {
5185 f(value, method, args, thread);
5186 }
5187
5188 void os::print_statistics() {
5189 }
5190
5191 bool os::message_box(const char* title, const char* message) {
5192 int i;
5193 fdStream err(defaultStream::error_fd());
5194 for (i = 0; i < 78; i++) err.print_raw("=");
5195 err.cr();
5196 err.print_raw_cr(title);
5197 for (i = 0; i < 78; i++) err.print_raw("-");
5198 err.cr();
5199 err.print_raw_cr(message);
5200 for (i = 0; i < 78; i++) err.print_raw("=");
5201 err.cr();
5202
5203 char buf[16];
5204 // Prevent process from exiting upon "read error" without consuming all CPU
5205 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5206
5207 return buf[0] == 'y' || buf[0] == 'Y';
5208 }
5209
5210 int os::stat(const char *path, struct stat *sbuf) {
5211 char pathbuf[MAX_PATH];
5212 if (strlen(path) > MAX_PATH - 1) {
5213 errno = ENAMETOOLONG;
5214 return -1;
5215 }
5216 os::native_path(strcpy(pathbuf, path));
5217 return ::stat(pathbuf, sbuf);
5218 }
5219
5220 // Is a (classpath) directory empty?
5221 bool os::dir_is_empty(const char* path) {
5222 DIR *dir = NULL;
5223 struct dirent *ptr;
5224
5225 dir = opendir(path);
5226 if (dir == NULL) return true;
5227
5228 // Scan the directory
5229 bool result = true;
5230 char buf[sizeof(struct dirent) + MAX_PATH];
5231 while (result && (ptr = ::readdir(dir)) != NULL) {
5232 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5233 result = false;
5234 }
5235 }
5236 closedir(dir);
5237 return result;
5238 }
5239
5240 // This code originates from JDK's sysOpen and open64_w
5241 // from src/solaris/hpi/src/system_md.c
5242
5243 int os::open(const char *path, int oflag, int mode) {
5244 if (strlen(path) > MAX_PATH - 1) {
5245 errno = ENAMETOOLONG;
5246 return -1;
5247 }
5248
5249 // All file descriptors that are opened in the Java process and not
5250 // specifically destined for a subprocess should have the close-on-exec
5251 // flag set. If we don't set it, then careless 3rd party native code
5252 // might fork and exec without closing all appropriate file descriptors
5253 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5254 // turn might:
5255 //
5256 // - cause end-of-file to fail to be detected on some file
5257 // descriptors, resulting in mysterious hangs, or
5258 //
5259 // - might cause an fopen in the subprocess to fail on a system
5260 // suffering from bug 1085341.
5261 //
5262 // (Yes, the default setting of the close-on-exec flag is a Unix
5263 // design flaw)
5264 //
5265 // See:
5266 // 1085341: 32-bit stdio routines should support file descriptors >255
5267 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5268 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5269 //
5270 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5271 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5272 // because it saves a system call and removes a small window where the flag
5273 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5274 // and we fall back to using FD_CLOEXEC (see below).
5275 #ifdef O_CLOEXEC
5276 oflag |= O_CLOEXEC;
5277 #endif
5278
5279 int fd = ::open64(path, oflag, mode);
5280 if (fd == -1) return -1;
5281
5282 //If the open succeeded, the file might still be a directory
5283 {
5284 struct stat64 buf64;
5285 int ret = ::fstat64(fd, &buf64);
5286 int st_mode = buf64.st_mode;
5287
5288 if (ret != -1) {
5289 if ((st_mode & S_IFMT) == S_IFDIR) {
5290 errno = EISDIR;
5291 ::close(fd);
5292 return -1;
5293 }
5294 } else {
5295 ::close(fd);
5296 return -1;
5297 }
5298 }
5299
5300 #ifdef FD_CLOEXEC
5301 // Validate that the use of the O_CLOEXEC flag on open above worked.
5302 // With recent kernels, we will perform this check exactly once.
5303 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5304 if (!O_CLOEXEC_is_known_to_work) {
5305 int flags = ::fcntl(fd, F_GETFD);
5306 if (flags != -1) {
5307 if ((flags & FD_CLOEXEC) != 0)
5308 O_CLOEXEC_is_known_to_work = 1;
5309 else
5310 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5311 }
5312 }
5313 #endif
5314
5315 return fd;
5316 }
5317
5318
5319 // create binary file, rewriting existing file if required
5320 int os::create_binary_file(const char* path, bool rewrite_existing) {
5321 int oflags = O_WRONLY | O_CREAT;
5322 if (!rewrite_existing) {
5323 oflags |= O_EXCL;
5324 }
5325 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5326 }
5327
5328 // return current position of file pointer
5329 jlong os::current_file_offset(int fd) {
5330 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5331 }
5332
5333 // move file pointer to the specified offset
5334 jlong os::seek_to_file_offset(int fd, jlong offset) {
5335 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5336 }
5337
5338 // This code originates from JDK's sysAvailable
5339 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5340
5341 int os::available(int fd, jlong *bytes) {
5342 jlong cur, end;
5343 int mode;
5344 struct stat64 buf64;
5345
5346 if (::fstat64(fd, &buf64) >= 0) {
5347 mode = buf64.st_mode;
5348 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5349 int n;
5350 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5351 *bytes = n;
5352 return 1;
5353 }
5354 }
5355 }
5356 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5357 return 0;
5358 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5359 return 0;
5360 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5361 return 0;
5362 }
5363 *bytes = end - cur;
5364 return 1;
5365 }
5366
5367 // Map a block of memory.
5368 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5369 char *addr, size_t bytes, bool read_only,
5370 bool allow_exec) {
5371 int prot;
5372 int flags = MAP_PRIVATE;
5373
5374 if (read_only) {
5375 prot = PROT_READ;
5376 } else {
5377 prot = PROT_READ | PROT_WRITE;
5378 }
5379
5380 if (allow_exec) {
5381 prot |= PROT_EXEC;
5382 }
5383
5384 if (addr != NULL) {
5385 flags |= MAP_FIXED;
5386 }
5387
5388 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5389 fd, file_offset);
5390 if (mapped_address == MAP_FAILED) {
5391 return NULL;
5392 }
5393 return mapped_address;
5394 }
5395
5396
5397 // Remap a block of memory.
5398 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5399 char *addr, size_t bytes, bool read_only,
5400 bool allow_exec) {
5401 // same as map_memory() on this OS
5402 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5403 allow_exec);
5404 }
5405
5406
5407 // Unmap a block of memory.
5408 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5409 return munmap(addr, bytes) == 0;
5410 }
5411
5412 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5413
5414 static clockid_t thread_cpu_clockid(Thread* thread) {
5415 pthread_t tid = thread->osthread()->pthread_id();
5416 clockid_t clockid;
5417
5418 // Get thread clockid
5419 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5420 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5421 return clockid;
5422 }
5423
5424 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5425 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5426 // of a thread.
5427 //
5428 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5429 // the fast estimate available on the platform.
5430
5431 jlong os::current_thread_cpu_time() {
5432 if (os::Linux::supports_fast_thread_cpu_time()) {
5433 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5434 } else {
5435 // return user + sys since the cost is the same
5436 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5437 }
5438 }
5439
5440 jlong os::thread_cpu_time(Thread* thread) {
5441 // consistent with what current_thread_cpu_time() returns
5442 if (os::Linux::supports_fast_thread_cpu_time()) {
5443 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5444 } else {
5445 return slow_thread_cpu_time(thread, true /* user + sys */);
5446 }
5447 }
5448
5449 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5450 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5451 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5452 } else {
5453 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5454 }
5455 }
5456
5457 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5458 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5459 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5460 } else {
5461 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5462 }
5463 }
5464
5465 // -1 on error.
5466 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5467 pid_t tid = thread->osthread()->thread_id();
5468 char *s;
5469 char stat[2048];
5470 int statlen;
5471 char proc_name[64];
5472 int count;
5473 long sys_time, user_time;
5474 char cdummy;
5475 int idummy;
5476 long ldummy;
5477 FILE *fp;
5478
5479 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5480 fp = fopen(proc_name, "r");
5481 if (fp == NULL) return -1;
5482 statlen = fread(stat, 1, 2047, fp);
5483 stat[statlen] = '\0';
5484 fclose(fp);
5485
5486 // Skip pid and the command string. Note that we could be dealing with
5487 // weird command names, e.g. user could decide to rename java launcher
5488 // to "java 1.4.2 :)", then the stat file would look like
5489 // 1234 (java 1.4.2 :)) R ... ...
5490 // We don't really need to know the command string, just find the last
5491 // occurrence of ")" and then start parsing from there. See bug 4726580.
5492 s = strrchr(stat, ')');
5493 if (s == NULL) return -1;
5494
5495 // Skip blank chars
5496 do { s++; } while (s && isspace(*s));
5497
5498 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5499 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5500 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5501 &user_time, &sys_time);
5502 if (count != 13) return -1;
5503 if (user_sys_cpu_time) {
5504 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5505 } else {
5506 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5507 }
5508 }
5509
5510 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5511 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5512 info_ptr->may_skip_backward = false; // elapsed time not wall time
5513 info_ptr->may_skip_forward = false; // elapsed time not wall time
5514 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5515 }
5516
5517 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5518 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5519 info_ptr->may_skip_backward = false; // elapsed time not wall time
5520 info_ptr->may_skip_forward = false; // elapsed time not wall time
5521 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5522 }
5523
5524 bool os::is_thread_cpu_time_supported() {
5525 return true;
5526 }
5527
5528 // System loadavg support. Returns -1 if load average cannot be obtained.
5529 // Linux doesn't yet have a (official) notion of processor sets,
5530 // so just return the system wide load average.
5531 int os::loadavg(double loadavg[], int nelem) {
5532 return ::getloadavg(loadavg, nelem);
5533 }
5534
5535 void os::pause() {
5536 char filename[MAX_PATH];
5537 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5538 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5539 } else {
5540 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5541 }
5542
5543 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5544 if (fd != -1) {
5545 struct stat buf;
5546 ::close(fd);
5547 while (::stat(filename, &buf) == 0) {
5548 (void)::poll(NULL, 0, 100);
5549 }
5550 } else {
5551 jio_fprintf(stderr,
5552 "Could not open pause file '%s', continuing immediately.\n", filename);
5553 }
5554 }
5555
5556 extern char** environ;
5557
5558 // Run the specified command in a separate process. Return its exit value,
5559 // or -1 on failure (e.g. can't fork a new process).
5560 // Unlike system(), this function can be called from signal handler. It
5561 // doesn't block SIGINT et al.
5562 int os::fork_and_exec(char* cmd) {
5563 const char * argv[4] = {"sh", "-c", cmd, NULL};
5564
5565 pid_t pid = fork();
5566
5567 if (pid < 0) {
5568 // fork failed
5569 return -1;
5570
5571 } else if (pid == 0) {
5572 // child process
5573
5574 execve("/bin/sh", (char* const*)argv, environ);
5575
5576 // execve failed
5577 _exit(-1);
5578
5579 } else {
5580 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5581 // care about the actual exit code, for now.
5582
5583 int status;
5584
5585 // Wait for the child process to exit. This returns immediately if
5586 // the child has already exited. */
5587 while (waitpid(pid, &status, 0) < 0) {
5588 switch (errno) {
5589 case ECHILD: return 0;
5590 case EINTR: break;
5591 default: return -1;
5592 }
5593 }
5594
5595 if (WIFEXITED(status)) {
5596 // The child exited normally; get its exit code.
5597 return WEXITSTATUS(status);
5598 } else if (WIFSIGNALED(status)) {
5599 // The child exited because of a signal
5600 // The best value to return is 0x80 + signal number,
5601 // because that is what all Unix shells do, and because
5602 // it allows callers to distinguish between process exit and
5603 // process death by signal.
5604 return 0x80 + WTERMSIG(status);
5605 } else {
5606 // Unknown exit code; pass it through
5607 return status;
5608 }
5609 }
5610 }
5611
5612 // is_headless_jre()
5613 //
5614 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5615 // in order to report if we are running in a headless jre
5616 //
5617 // Since JDK8 xawt/libmawt.so was moved into the same directory
5618 // as libawt.so, and renamed libawt_xawt.so
5619 //
5620 bool os::is_headless_jre() {
5621 struct stat statbuf;
5622 char buf[MAXPATHLEN];
5623 char libmawtpath[MAXPATHLEN];
5624 const char *xawtstr = "/xawt/libmawt.so";
5625 const char *new_xawtstr = "/libawt_xawt.so";
5626 char *p;
5627
5628 // Get path to libjvm.so
5629 os::jvm_path(buf, sizeof(buf));
5630
5631 // Get rid of libjvm.so
5632 p = strrchr(buf, '/');
5633 if (p == NULL) {
5634 return false;
5635 } else {
5636 *p = '\0';
5637 }
5638
5639 // Get rid of client or server
5640 p = strrchr(buf, '/');
5641 if (p == NULL) {
5642 return false;
5643 } else {
5644 *p = '\0';
5645 }
5646
5647 // check xawt/libmawt.so
5648 strcpy(libmawtpath, buf);
5649 strcat(libmawtpath, xawtstr);
5650 if (::stat(libmawtpath, &statbuf) == 0) return false;
5651
5652 // check libawt_xawt.so
5653 strcpy(libmawtpath, buf);
5654 strcat(libmawtpath, new_xawtstr);
5655 if (::stat(libmawtpath, &statbuf) == 0) return false;
5656
5657 return true;
5658 }
5659
5660 // Get the default path to the core file
5661 // Returns the length of the string
5662 int os::get_core_path(char* buffer, size_t bufferSize) {
5663 /*
5664 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5665 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5666 */
5667 const int core_pattern_len = 129;
5668 char core_pattern[core_pattern_len] = {0};
5669
5670 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5671 if (core_pattern_file == -1) {
5672 return -1;
5673 }
5674
5675 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5676 ::close(core_pattern_file);
5677 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5678 return -1;
5679 }
5680 if (core_pattern[ret-1] == '\n') {
5681 core_pattern[ret-1] = '\0';
5682 } else {
5683 core_pattern[ret] = '\0';
5684 }
5685
5686 char *pid_pos = strstr(core_pattern, "%p");
5687 int written;
5688
5689 if (core_pattern[0] == '/') {
5690 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5691 } else {
5692 char cwd[PATH_MAX];
5693
5694 const char* p = get_current_directory(cwd, PATH_MAX);
5695 if (p == NULL) {
5696 return -1;
5697 }
5698
5699 if (core_pattern[0] == '|') {
5700 written = jio_snprintf(buffer, bufferSize,
5701 "\"%s\" (or dumping to %s/core.%d)",
5702 &core_pattern[1], p, current_process_id());
5703 } else {
5704 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5705 }
5706 }
5707
5708 if (written < 0) {
5709 return -1;
5710 }
5711
5712 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5713 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5714
5715 if (core_uses_pid_file != -1) {
5716 char core_uses_pid = 0;
5717 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5718 ::close(core_uses_pid_file);
5719
5720 if (core_uses_pid == '1') {
5721 jio_snprintf(buffer + written, bufferSize - written,
5722 ".%d", current_process_id());
5723 }
5724 }
5725 }
5726
5727 return strlen(buffer);
5728 }
5729
5730 bool os::start_debugging(char *buf, int buflen) {
5731 int len = (int)strlen(buf);
5732 char *p = &buf[len];
5733
5734 jio_snprintf(p, buflen-len,
5735 "\n\n"
5736 "Do you want to debug the problem?\n\n"
5737 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
5738 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
5739 "Otherwise, press RETURN to abort...",
5740 os::current_process_id(), os::current_process_id(),
5741 os::current_thread_id(), os::current_thread_id());
5742
5743 bool yes = os::message_box("Unexpected Error", buf);
5744
5745 if (yes) {
5746 // yes, user asked VM to launch debugger
5747 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
5748 os::current_process_id(), os::current_process_id());
5749
5750 os::fork_and_exec(buf);
5751 yes = false;
5752 }
5753 return yes;
5754 }
5755
5756
5757 // Java/Compiler thread:
5758 //
5759 // Low memory addresses
5760 // P0 +------------------------+
5761 // | |\ Java thread created by VM does not have glibc
5762 // | glibc guard page | - guard page, attached Java thread usually has
5763 // | |/ 1 glibc guard page.
5764 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5765 // | |\
5766 // | HotSpot Guard Pages | - red, yellow and reserved pages
5767 // | |/
5768 // +------------------------+ JavaThread::stack_reserved_zone_base()
5769 // | |\
5770 // | Normal Stack | -
5771 // | |/
5772 // P2 +------------------------+ Thread::stack_base()
5773 //
5774 // Non-Java thread:
5775 //
5776 // Low memory addresses
5777 // P0 +------------------------+
5778 // | |\
5779 // | glibc guard page | - usually 1 page
5780 // | |/
5781 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5782 // | |\
5783 // | Normal Stack | -
5784 // | |/
5785 // P2 +------------------------+ Thread::stack_base()
5786 //
5787 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
5788 // returned from pthread_attr_getstack().
5789 // ** Due to NPTL implementation error, linux takes the glibc guard page out
5790 // of the stack size given in pthread_attr. We work around this for
5791 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
5792 //
5793 #ifndef ZERO
5794 static void current_stack_region(address * bottom, size_t * size) {
5795 if (os::Linux::is_initial_thread()) {
5796 // initial thread needs special handling because pthread_getattr_np()
5797 // may return bogus value.
5798 *bottom = os::Linux::initial_thread_stack_bottom();
5799 *size = os::Linux::initial_thread_stack_size();
5800 } else {
5801 pthread_attr_t attr;
5802
5803 int rslt = pthread_getattr_np(pthread_self(), &attr);
5804
5805 // JVM needs to know exact stack location, abort if it fails
5806 if (rslt != 0) {
5807 if (rslt == ENOMEM) {
5808 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
5809 } else {
5810 fatal("pthread_getattr_np failed with error = %d", rslt);
5811 }
5812 }
5813
5814 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
5815 fatal("Cannot locate current stack attributes!");
5816 }
5817
5818 // Work around NPTL stack guard error.
5819 size_t guard_size = 0;
5820 rslt = pthread_attr_getguardsize(&attr, &guard_size);
5821 if (rslt != 0) {
5822 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
5823 }
5824 *bottom += guard_size;
5825 *size -= guard_size;
5826
5827 pthread_attr_destroy(&attr);
5828
5829 }
5830 assert(os::current_stack_pointer() >= *bottom &&
5831 os::current_stack_pointer() < *bottom + *size, "just checking");
5832 }
5833
5834 address os::current_stack_base() {
5835 address bottom;
5836 size_t size;
5837 current_stack_region(&bottom, &size);
5838 return (bottom + size);
5839 }
5840
5841 size_t os::current_stack_size() {
5842 // This stack size includes the usable stack and HotSpot guard pages
5843 // (for the threads that have Hotspot guard pages).
5844 address bottom;
5845 size_t size;
5846 current_stack_region(&bottom, &size);
5847 return size;
5848 }
5849 #endif
5850
5851 static inline struct timespec get_mtime(const char* filename) {
5852 struct stat st;
5853 int ret = os::stat(filename, &st);
5854 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
5855 return st.st_mtim;
5856 }
5857
5858 int os::compare_file_modified_times(const char* file1, const char* file2) {
5859 struct timespec filetime1 = get_mtime(file1);
5860 struct timespec filetime2 = get_mtime(file2);
5861 int diff = filetime1.tv_sec - filetime2.tv_sec;
5862 if (diff == 0) {
5863 return filetime1.tv_nsec - filetime2.tv_nsec;
5864 }
5865 return diff;
5866 }
5867
5868 /////////////// Unit tests ///////////////
5869
5870 #ifndef PRODUCT
5871
5872 #define test_log(...) \
5873 do { \
5874 if (VerboseInternalVMTests) { \
5875 tty->print_cr(__VA_ARGS__); \
5876 tty->flush(); \
5877 } \
5878 } while (false)
5879
5880 class TestReserveMemorySpecial : AllStatic {
5881 public:
5882 static void small_page_write(void* addr, size_t size) {
5883 size_t page_size = os::vm_page_size();
5884
5885 char* end = (char*)addr + size;
5886 for (char* p = (char*)addr; p < end; p += page_size) {
5887 *p = 1;
5888 }
5889 }
5890
5891 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
5892 if (!UseHugeTLBFS) {
5893 return;
5894 }
5895
5896 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
5897
5898 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
5899
5900 if (addr != NULL) {
5901 small_page_write(addr, size);
5902
5903 os::Linux::release_memory_special_huge_tlbfs(addr, size);
5904 }
5905 }
5906
5907 static void test_reserve_memory_special_huge_tlbfs_only() {
5908 if (!UseHugeTLBFS) {
5909 return;
5910 }
5911
5912 size_t lp = os::large_page_size();
5913
5914 for (size_t size = lp; size <= lp * 10; size += lp) {
5915 test_reserve_memory_special_huge_tlbfs_only(size);
5916 }
5917 }
5918
5919 static void test_reserve_memory_special_huge_tlbfs_mixed() {
5920 size_t lp = os::large_page_size();
5921 size_t ag = os::vm_allocation_granularity();
5922
5923 // sizes to test
5924 const size_t sizes[] = {
5925 lp, lp + ag, lp + lp / 2, lp * 2,
5926 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
5927 lp * 10, lp * 10 + lp / 2
5928 };
5929 const int num_sizes = sizeof(sizes) / sizeof(size_t);
5930
5931 // For each size/alignment combination, we test three scenarios:
5932 // 1) with req_addr == NULL
5933 // 2) with a non-null req_addr at which we expect to successfully allocate
5934 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
5935 // expect the allocation to either fail or to ignore req_addr
5936
5937 // Pre-allocate two areas; they shall be as large as the largest allocation
5938 // and aligned to the largest alignment we will be testing.
5939 const size_t mapping_size = sizes[num_sizes - 1] * 2;
5940 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
5941 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
5942 -1, 0);
5943 assert(mapping1 != MAP_FAILED, "should work");
5944
5945 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
5946 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
5947 -1, 0);
5948 assert(mapping2 != MAP_FAILED, "should work");
5949
5950 // Unmap the first mapping, but leave the second mapping intact: the first
5951 // mapping will serve as a value for a "good" req_addr (case 2). The second
5952 // mapping, still intact, as "bad" req_addr (case 3).
5953 ::munmap(mapping1, mapping_size);
5954
5955 // Case 1
5956 test_log("%s, req_addr NULL:", __FUNCTION__);
5957 test_log("size align result");
5958
5959 for (int i = 0; i < num_sizes; i++) {
5960 const size_t size = sizes[i];
5961 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5962 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
5963 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
5964 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
5965 if (p != NULL) {
5966 assert(is_ptr_aligned(p, alignment), "must be");
5967 small_page_write(p, size);
5968 os::Linux::release_memory_special_huge_tlbfs(p, size);
5969 }
5970 }
5971 }
5972
5973 // Case 2
5974 test_log("%s, req_addr non-NULL:", __FUNCTION__);
5975 test_log("size align req_addr result");
5976
5977 for (int i = 0; i < num_sizes; i++) {
5978 const size_t size = sizes[i];
5979 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5980 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
5981 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
5982 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
5983 size, alignment, p2i(req_addr), p2i(p),
5984 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
5985 if (p != NULL) {
5986 assert(p == req_addr, "must be");
5987 small_page_write(p, size);
5988 os::Linux::release_memory_special_huge_tlbfs(p, size);
5989 }
5990 }
5991 }
5992
5993 // Case 3
5994 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
5995 test_log("size align req_addr result");
5996
5997 for (int i = 0; i < num_sizes; i++) {
5998 const size_t size = sizes[i];
5999 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6000 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6001 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6002 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6003 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6004 // as the area around req_addr contains already existing mappings, the API should always
6005 // return NULL (as per contract, it cannot return another address)
6006 assert(p == NULL, "must be");
6007 }
6008 }
6009
6010 ::munmap(mapping2, mapping_size);
6011
6012 }
6013
6014 static void test_reserve_memory_special_huge_tlbfs() {
6015 if (!UseHugeTLBFS) {
6016 return;
6017 }
6018
6019 test_reserve_memory_special_huge_tlbfs_only();
6020 test_reserve_memory_special_huge_tlbfs_mixed();
6021 }
6022
6023 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6024 if (!UseSHM) {
6025 return;
6026 }
6027
6028 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6029
6030 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6031
6032 if (addr != NULL) {
6033 assert(is_ptr_aligned(addr, alignment), "Check");
6034 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6035
6036 small_page_write(addr, size);
6037
6038 os::Linux::release_memory_special_shm(addr, size);
6039 }
6040 }
6041
6042 static void test_reserve_memory_special_shm() {
6043 size_t lp = os::large_page_size();
6044 size_t ag = os::vm_allocation_granularity();
6045
6046 for (size_t size = ag; size < lp * 3; size += ag) {
6047 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6048 test_reserve_memory_special_shm(size, alignment);
6049 }
6050 }
6051 }
6052
6053 static void test() {
6054 test_reserve_memory_special_huge_tlbfs();
6055 test_reserve_memory_special_shm();
6056 }
6057 };
6058
6059 void TestReserveMemorySpecial_test() {
6060 TestReserveMemorySpecial::test();
6061 }
6062
6063 #endif