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 int max_node = Linux::numa_max_node();
2740 return max_node > 0 ? max_node + 1 : 1;
2741 }
2742
2743 int os::numa_get_group_id() {
2744 int cpu_id = Linux::sched_getcpu();
2745 if (cpu_id != -1) {
2746 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2747 if (lgrp_id != -1) {
2748 return lgrp_id;
2749 }
2750 }
2751 return 0;
2752 }
2753
2754 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2755 for (size_t i = 0; i < size; i++) {
2756 ids[i] = i;
2757 }
2758 return size;
2759 }
2760
2761 bool os::get_page_info(char *start, page_info* info) {
2762 return false;
2763 }
2764
2765 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2766 page_info* page_found) {
2767 return end;
2768 }
2769
2770
2771 int os::Linux::sched_getcpu_syscall(void) {
2772 unsigned int cpu = 0;
2773 int retval = -1;
2774
2775 #if defined(IA32)
2776 #ifndef SYS_getcpu
2777 #define SYS_getcpu 318
2778 #endif
2779 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2780 #elif defined(AMD64)
2781 // Unfortunately we have to bring all these macros here from vsyscall.h
2782 // to be able to compile on old linuxes.
2783 #define __NR_vgetcpu 2
2784 #define VSYSCALL_START (-10UL << 20)
2785 #define VSYSCALL_SIZE 1024
2786 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2787 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2788 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2789 retval = vgetcpu(&cpu, NULL, NULL);
2790 #endif
2791
2792 return (retval == -1) ? retval : cpu;
2793 }
2794
2795 // Something to do with the numa-aware allocator needs these symbols
2796 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2797 extern "C" JNIEXPORT void numa_error(char *where) { }
2798
2799
2800 // If we are running with libnuma version > 2, then we should
2801 // be trying to use symbols with versions 1.1
2802 // If we are running with earlier version, which did not have symbol versions,
2803 // we should use the base version.
2804 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2805 void *f = dlvsym(handle, name, "libnuma_1.1");
2806 if (f == NULL) {
2807 f = dlsym(handle, name);
2808 }
2809 return f;
2810 }
2811
2812 bool os::Linux::libnuma_init() {
2813 // sched_getcpu() should be in libc.
2814 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2815 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2816
2817 // If it's not, try a direct syscall.
2818 if (sched_getcpu() == -1) {
2819 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2820 (void*)&sched_getcpu_syscall));
2821 }
2822
2823 if (sched_getcpu() != -1) { // Does it work?
2824 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2825 if (handle != NULL) {
2826 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2827 libnuma_dlsym(handle, "numa_node_to_cpus")));
2828 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2829 libnuma_dlsym(handle, "numa_max_node")));
2830 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2831 libnuma_dlsym(handle, "numa_available")));
2832 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2833 libnuma_dlsym(handle, "numa_tonode_memory")));
2834 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2835 libnuma_dlsym(handle, "numa_interleave_memory")));
2836 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2837 libnuma_dlsym(handle, "numa_set_bind_policy")));
2838
2839
2840 if (numa_available() != -1) {
2841 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2842 // Create a cpu -> node mapping
2843 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2844 rebuild_cpu_to_node_map();
2845 return true;
2846 }
2847 }
2848 }
2849 return false;
2850 }
2851
2852 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
2853 // Creating guard page is very expensive. Java thread has HotSpot
2854 // guard pages, only enable glibc guard page for non-Java threads.
2855 // (Remember: compiler thread is a Java thread, too!)
2856 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
2857 }
2858
2859 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2860 // The table is later used in get_node_by_cpu().
2861 void os::Linux::rebuild_cpu_to_node_map() {
2862 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2863 // in libnuma (possible values are starting from 16,
2864 // and continuing up with every other power of 2, but less
2865 // than the maximum number of CPUs supported by kernel), and
2866 // is a subject to change (in libnuma version 2 the requirements
2867 // are more reasonable) we'll just hardcode the number they use
2868 // in the library.
2869 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2870
2871 size_t cpu_num = processor_count();
2872 size_t cpu_map_size = NCPUS / BitsPerCLong;
2873 size_t cpu_map_valid_size =
2874 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2875
2876 cpu_to_node()->clear();
2877 cpu_to_node()->at_grow(cpu_num - 1);
2878 size_t node_num = numa_get_groups_num();
2879
2880 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2881 for (size_t i = 0; i < node_num; i++) {
2882 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2883 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2884 if (cpu_map[j] != 0) {
2885 for (size_t k = 0; k < BitsPerCLong; k++) {
2886 if (cpu_map[j] & (1UL << k)) {
2887 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2888 }
2889 }
2890 }
2891 }
2892 }
2893 }
2894 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2895 }
2896
2897 int os::Linux::get_node_by_cpu(int cpu_id) {
2898 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2899 return cpu_to_node()->at(cpu_id);
2900 }
2901 return -1;
2902 }
2903
2904 GrowableArray<int>* os::Linux::_cpu_to_node;
2905 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2906 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2907 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2908 os::Linux::numa_available_func_t os::Linux::_numa_available;
2909 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2910 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2911 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2912 unsigned long* os::Linux::_numa_all_nodes;
2913
2914 bool os::pd_uncommit_memory(char* addr, size_t size) {
2915 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2916 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2917 return res != (uintptr_t) MAP_FAILED;
2918 }
2919
2920 static address get_stack_commited_bottom(address bottom, size_t size) {
2921 address nbot = bottom;
2922 address ntop = bottom + size;
2923
2924 size_t page_sz = os::vm_page_size();
2925 unsigned pages = size / page_sz;
2926
2927 unsigned char vec[1];
2928 unsigned imin = 1, imax = pages + 1, imid;
2929 int mincore_return_value = 0;
2930
2931 assert(imin <= imax, "Unexpected page size");
2932
2933 while (imin < imax) {
2934 imid = (imax + imin) / 2;
2935 nbot = ntop - (imid * page_sz);
2936
2937 // Use a trick with mincore to check whether the page is mapped or not.
2938 // mincore sets vec to 1 if page resides in memory and to 0 if page
2939 // is swapped output but if page we are asking for is unmapped
2940 // it returns -1,ENOMEM
2941 mincore_return_value = mincore(nbot, page_sz, vec);
2942
2943 if (mincore_return_value == -1) {
2944 // Page is not mapped go up
2945 // to find first mapped page
2946 if (errno != EAGAIN) {
2947 assert(errno == ENOMEM, "Unexpected mincore errno");
2948 imax = imid;
2949 }
2950 } else {
2951 // Page is mapped go down
2952 // to find first not mapped page
2953 imin = imid + 1;
2954 }
2955 }
2956
2957 nbot = nbot + page_sz;
2958
2959 // Adjust stack bottom one page up if last checked page is not mapped
2960 if (mincore_return_value == -1) {
2961 nbot = nbot + page_sz;
2962 }
2963
2964 return nbot;
2965 }
2966
2967
2968 // Linux uses a growable mapping for the stack, and if the mapping for
2969 // the stack guard pages is not removed when we detach a thread the
2970 // stack cannot grow beyond the pages where the stack guard was
2971 // mapped. If at some point later in the process the stack expands to
2972 // that point, the Linux kernel cannot expand the stack any further
2973 // because the guard pages are in the way, and a segfault occurs.
2974 //
2975 // However, it's essential not to split the stack region by unmapping
2976 // a region (leaving a hole) that's already part of the stack mapping,
2977 // so if the stack mapping has already grown beyond the guard pages at
2978 // the time we create them, we have to truncate the stack mapping.
2979 // So, we need to know the extent of the stack mapping when
2980 // create_stack_guard_pages() is called.
2981
2982 // We only need this for stacks that are growable: at the time of
2983 // writing thread stacks don't use growable mappings (i.e. those
2984 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2985 // only applies to the main thread.
2986
2987 // If the (growable) stack mapping already extends beyond the point
2988 // where we're going to put our guard pages, truncate the mapping at
2989 // that point by munmap()ping it. This ensures that when we later
2990 // munmap() the guard pages we don't leave a hole in the stack
2991 // mapping. This only affects the main/initial thread
2992
2993 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2994 if (os::Linux::is_initial_thread()) {
2995 // As we manually grow stack up to bottom inside create_attached_thread(),
2996 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
2997 // we don't need to do anything special.
2998 // Check it first, before calling heavy function.
2999 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3000 unsigned char vec[1];
3001
3002 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3003 // Fallback to slow path on all errors, including EAGAIN
3004 stack_extent = (uintptr_t) get_stack_commited_bottom(
3005 os::Linux::initial_thread_stack_bottom(),
3006 (size_t)addr - stack_extent);
3007 }
3008
3009 if (stack_extent < (uintptr_t)addr) {
3010 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3011 }
3012 }
3013
3014 return os::commit_memory(addr, size, !ExecMem);
3015 }
3016
3017 // If this is a growable mapping, remove the guard pages entirely by
3018 // munmap()ping them. If not, just call uncommit_memory(). This only
3019 // affects the main/initial thread, but guard against future OS changes
3020 // It's safe to always unmap guard pages for initial thread because we
3021 // always place it right after end of the mapped region
3022
3023 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3024 uintptr_t stack_extent, stack_base;
3025
3026 if (os::Linux::is_initial_thread()) {
3027 return ::munmap(addr, size) == 0;
3028 }
3029
3030 return os::uncommit_memory(addr, size);
3031 }
3032
3033 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3034 // at 'requested_addr'. If there are existing memory mappings at the same
3035 // location, however, they will be overwritten. If 'fixed' is false,
3036 // 'requested_addr' is only treated as a hint, the return value may or
3037 // may not start from the requested address. Unlike Linux mmap(), this
3038 // function returns NULL to indicate failure.
3039 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3040 char * addr;
3041 int flags;
3042
3043 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3044 if (fixed) {
3045 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3046 flags |= MAP_FIXED;
3047 }
3048
3049 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3050 // touch an uncommitted page. Otherwise, the read/write might
3051 // succeed if we have enough swap space to back the physical page.
3052 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3053 flags, -1, 0);
3054
3055 return addr == MAP_FAILED ? NULL : addr;
3056 }
3057
3058 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3059 // (req_addr != NULL) or with a given alignment.
3060 // - bytes shall be a multiple of alignment.
3061 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3062 // - alignment sets the alignment at which memory shall be allocated.
3063 // It must be a multiple of allocation granularity.
3064 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3065 // req_addr or NULL.
3066 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3067
3068 size_t extra_size = bytes;
3069 if (req_addr == NULL && alignment > 0) {
3070 extra_size += alignment;
3071 }
3072
3073 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3074 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3075 -1, 0);
3076 if (start == MAP_FAILED) {
3077 start = NULL;
3078 } else {
3079 if (req_addr != NULL) {
3080 if (start != req_addr) {
3081 ::munmap(start, extra_size);
3082 start = NULL;
3083 }
3084 } else {
3085 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3086 char* const end_aligned = start_aligned + bytes;
3087 char* const end = start + extra_size;
3088 if (start_aligned > start) {
3089 ::munmap(start, start_aligned - start);
3090 }
3091 if (end_aligned < end) {
3092 ::munmap(end_aligned, end - end_aligned);
3093 }
3094 start = start_aligned;
3095 }
3096 }
3097 return start;
3098 }
3099
3100 static int anon_munmap(char * addr, size_t size) {
3101 return ::munmap(addr, size) == 0;
3102 }
3103
3104 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3105 size_t alignment_hint) {
3106 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3107 }
3108
3109 bool os::pd_release_memory(char* addr, size_t size) {
3110 return anon_munmap(addr, size);
3111 }
3112
3113 static bool linux_mprotect(char* addr, size_t size, int prot) {
3114 // Linux wants the mprotect address argument to be page aligned.
3115 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3116
3117 // According to SUSv3, mprotect() should only be used with mappings
3118 // established by mmap(), and mmap() always maps whole pages. Unaligned
3119 // 'addr' likely indicates problem in the VM (e.g. trying to change
3120 // protection of malloc'ed or statically allocated memory). Check the
3121 // caller if you hit this assert.
3122 assert(addr == bottom, "sanity check");
3123
3124 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3125 return ::mprotect(bottom, size, prot) == 0;
3126 }
3127
3128 // Set protections specified
3129 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3130 bool is_committed) {
3131 unsigned int p = 0;
3132 switch (prot) {
3133 case MEM_PROT_NONE: p = PROT_NONE; break;
3134 case MEM_PROT_READ: p = PROT_READ; break;
3135 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3136 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3137 default:
3138 ShouldNotReachHere();
3139 }
3140 // is_committed is unused.
3141 return linux_mprotect(addr, bytes, p);
3142 }
3143
3144 bool os::guard_memory(char* addr, size_t size) {
3145 return linux_mprotect(addr, size, PROT_NONE);
3146 }
3147
3148 bool os::unguard_memory(char* addr, size_t size) {
3149 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3150 }
3151
3152 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3153 size_t page_size) {
3154 bool result = false;
3155 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3156 MAP_ANONYMOUS|MAP_PRIVATE,
3157 -1, 0);
3158 if (p != MAP_FAILED) {
3159 void *aligned_p = align_ptr_up(p, page_size);
3160
3161 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3162
3163 munmap(p, page_size * 2);
3164 }
3165
3166 if (warn && !result) {
3167 warning("TransparentHugePages is not supported by the operating system.");
3168 }
3169
3170 return result;
3171 }
3172
3173 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3174 bool result = false;
3175 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3176 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3177 -1, 0);
3178
3179 if (p != MAP_FAILED) {
3180 // We don't know if this really is a huge page or not.
3181 FILE *fp = fopen("/proc/self/maps", "r");
3182 if (fp) {
3183 while (!feof(fp)) {
3184 char chars[257];
3185 long x = 0;
3186 if (fgets(chars, sizeof(chars), fp)) {
3187 if (sscanf(chars, "%lx-%*x", &x) == 1
3188 && x == (long)p) {
3189 if (strstr (chars, "hugepage")) {
3190 result = true;
3191 break;
3192 }
3193 }
3194 }
3195 }
3196 fclose(fp);
3197 }
3198 munmap(p, page_size);
3199 }
3200
3201 if (warn && !result) {
3202 warning("HugeTLBFS is not supported by the operating system.");
3203 }
3204
3205 return result;
3206 }
3207
3208 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3209 //
3210 // From the coredump_filter documentation:
3211 //
3212 // - (bit 0) anonymous private memory
3213 // - (bit 1) anonymous shared memory
3214 // - (bit 2) file-backed private memory
3215 // - (bit 3) file-backed shared memory
3216 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3217 // effective only if the bit 2 is cleared)
3218 // - (bit 5) hugetlb private memory
3219 // - (bit 6) hugetlb shared memory
3220 //
3221 static void set_coredump_filter(void) {
3222 FILE *f;
3223 long cdm;
3224
3225 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3226 return;
3227 }
3228
3229 if (fscanf(f, "%lx", &cdm) != 1) {
3230 fclose(f);
3231 return;
3232 }
3233
3234 rewind(f);
3235
3236 if ((cdm & LARGEPAGES_BIT) == 0) {
3237 cdm |= LARGEPAGES_BIT;
3238 fprintf(f, "%#lx", cdm);
3239 }
3240
3241 fclose(f);
3242 }
3243
3244 // Large page support
3245
3246 static size_t _large_page_size = 0;
3247
3248 size_t os::Linux::find_large_page_size() {
3249 size_t large_page_size = 0;
3250
3251 // large_page_size on Linux is used to round up heap size. x86 uses either
3252 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3253 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3254 // page as large as 256M.
3255 //
3256 // Here we try to figure out page size by parsing /proc/meminfo and looking
3257 // for a line with the following format:
3258 // Hugepagesize: 2048 kB
3259 //
3260 // If we can't determine the value (e.g. /proc is not mounted, or the text
3261 // format has been changed), we'll use the largest page size supported by
3262 // the processor.
3263
3264 #ifndef ZERO
3265 large_page_size =
3266 AARCH64_ONLY(2 * M)
3267 AMD64_ONLY(2 * M)
3268 ARM32_ONLY(2 * M)
3269 IA32_ONLY(4 * M)
3270 IA64_ONLY(256 * M)
3271 PPC_ONLY(4 * M)
3272 S390_ONLY(1 * M)
3273 SPARC_ONLY(4 * M);
3274 #endif // ZERO
3275
3276 FILE *fp = fopen("/proc/meminfo", "r");
3277 if (fp) {
3278 while (!feof(fp)) {
3279 int x = 0;
3280 char buf[16];
3281 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3282 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3283 large_page_size = x * K;
3284 break;
3285 }
3286 } else {
3287 // skip to next line
3288 for (;;) {
3289 int ch = fgetc(fp);
3290 if (ch == EOF || ch == (int)'\n') break;
3291 }
3292 }
3293 }
3294 fclose(fp);
3295 }
3296
3297 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3298 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3299 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3300 proper_unit_for_byte_size(large_page_size));
3301 }
3302
3303 return large_page_size;
3304 }
3305
3306 size_t os::Linux::setup_large_page_size() {
3307 _large_page_size = Linux::find_large_page_size();
3308 const size_t default_page_size = (size_t)Linux::page_size();
3309 if (_large_page_size > default_page_size) {
3310 _page_sizes[0] = _large_page_size;
3311 _page_sizes[1] = default_page_size;
3312 _page_sizes[2] = 0;
3313 }
3314
3315 return _large_page_size;
3316 }
3317
3318 bool os::Linux::setup_large_page_type(size_t page_size) {
3319 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3320 FLAG_IS_DEFAULT(UseSHM) &&
3321 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3322
3323 // The type of large pages has not been specified by the user.
3324
3325 // Try UseHugeTLBFS and then UseSHM.
3326 UseHugeTLBFS = UseSHM = true;
3327
3328 // Don't try UseTransparentHugePages since there are known
3329 // performance issues with it turned on. This might change in the future.
3330 UseTransparentHugePages = false;
3331 }
3332
3333 if (UseTransparentHugePages) {
3334 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3335 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3336 UseHugeTLBFS = false;
3337 UseSHM = false;
3338 return true;
3339 }
3340 UseTransparentHugePages = false;
3341 }
3342
3343 if (UseHugeTLBFS) {
3344 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3345 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3346 UseSHM = false;
3347 return true;
3348 }
3349 UseHugeTLBFS = false;
3350 }
3351
3352 return UseSHM;
3353 }
3354
3355 void os::large_page_init() {
3356 if (!UseLargePages &&
3357 !UseTransparentHugePages &&
3358 !UseHugeTLBFS &&
3359 !UseSHM) {
3360 // Not using large pages.
3361 return;
3362 }
3363
3364 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3365 // The user explicitly turned off large pages.
3366 // Ignore the rest of the large pages flags.
3367 UseTransparentHugePages = false;
3368 UseHugeTLBFS = false;
3369 UseSHM = false;
3370 return;
3371 }
3372
3373 size_t large_page_size = Linux::setup_large_page_size();
3374 UseLargePages = Linux::setup_large_page_type(large_page_size);
3375
3376 set_coredump_filter();
3377 }
3378
3379 #ifndef SHM_HUGETLB
3380 #define SHM_HUGETLB 04000
3381 #endif
3382
3383 #define shm_warning_format(format, ...) \
3384 do { \
3385 if (UseLargePages && \
3386 (!FLAG_IS_DEFAULT(UseLargePages) || \
3387 !FLAG_IS_DEFAULT(UseSHM) || \
3388 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3389 warning(format, __VA_ARGS__); \
3390 } \
3391 } while (0)
3392
3393 #define shm_warning(str) shm_warning_format("%s", str)
3394
3395 #define shm_warning_with_errno(str) \
3396 do { \
3397 int err = errno; \
3398 shm_warning_format(str " (error = %d)", err); \
3399 } while (0)
3400
3401 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3402 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3403
3404 if (!is_size_aligned(alignment, SHMLBA)) {
3405 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3406 return NULL;
3407 }
3408
3409 // To ensure that we get 'alignment' aligned memory from shmat,
3410 // we pre-reserve aligned virtual memory and then attach to that.
3411
3412 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3413 if (pre_reserved_addr == NULL) {
3414 // Couldn't pre-reserve aligned memory.
3415 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3416 return NULL;
3417 }
3418
3419 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3420 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3421
3422 if ((intptr_t)addr == -1) {
3423 int err = errno;
3424 shm_warning_with_errno("Failed to attach shared memory.");
3425
3426 assert(err != EACCES, "Unexpected error");
3427 assert(err != EIDRM, "Unexpected error");
3428 assert(err != EINVAL, "Unexpected error");
3429
3430 // Since we don't know if the kernel unmapped the pre-reserved memory area
3431 // we can't unmap it, since that would potentially unmap memory that was
3432 // mapped from other threads.
3433 return NULL;
3434 }
3435
3436 return addr;
3437 }
3438
3439 static char* shmat_at_address(int shmid, char* req_addr) {
3440 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3441 assert(false, "Requested address needs to be SHMLBA aligned");
3442 return NULL;
3443 }
3444
3445 char* addr = (char*)shmat(shmid, req_addr, 0);
3446
3447 if ((intptr_t)addr == -1) {
3448 shm_warning_with_errno("Failed to attach shared memory.");
3449 return NULL;
3450 }
3451
3452 return addr;
3453 }
3454
3455 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3456 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3457 if (req_addr != NULL) {
3458 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3459 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3460 return shmat_at_address(shmid, req_addr);
3461 }
3462
3463 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3464 // return large page size aligned memory addresses when req_addr == NULL.
3465 // However, if the alignment is larger than the large page size, we have
3466 // to manually ensure that the memory returned is 'alignment' aligned.
3467 if (alignment > os::large_page_size()) {
3468 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3469 return shmat_with_alignment(shmid, bytes, alignment);
3470 } else {
3471 return shmat_at_address(shmid, NULL);
3472 }
3473 }
3474
3475 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3476 char* req_addr, bool exec) {
3477 // "exec" is passed in but not used. Creating the shared image for
3478 // the code cache doesn't have an SHM_X executable permission to check.
3479 assert(UseLargePages && UseSHM, "only for SHM large pages");
3480 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3481 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3482
3483 if (!is_size_aligned(bytes, os::large_page_size())) {
3484 return NULL; // Fallback to small pages.
3485 }
3486
3487 // Create a large shared memory region to attach to based on size.
3488 // Currently, size is the total size of the heap.
3489 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3490 if (shmid == -1) {
3491 // Possible reasons for shmget failure:
3492 // 1. shmmax is too small for Java heap.
3493 // > check shmmax value: cat /proc/sys/kernel/shmmax
3494 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3495 // 2. not enough large page memory.
3496 // > check available large pages: cat /proc/meminfo
3497 // > increase amount of large pages:
3498 // echo new_value > /proc/sys/vm/nr_hugepages
3499 // Note 1: different Linux may use different name for this property,
3500 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3501 // Note 2: it's possible there's enough physical memory available but
3502 // they are so fragmented after a long run that they can't
3503 // coalesce into large pages. Try to reserve large pages when
3504 // the system is still "fresh".
3505 shm_warning_with_errno("Failed to reserve shared memory.");
3506 return NULL;
3507 }
3508
3509 // Attach to the region.
3510 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3511
3512 // Remove shmid. If shmat() is successful, the actual shared memory segment
3513 // will be deleted when it's detached by shmdt() or when the process
3514 // terminates. If shmat() is not successful this will remove the shared
3515 // segment immediately.
3516 shmctl(shmid, IPC_RMID, NULL);
3517
3518 return addr;
3519 }
3520
3521 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3522 int error) {
3523 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3524
3525 bool warn_on_failure = UseLargePages &&
3526 (!FLAG_IS_DEFAULT(UseLargePages) ||
3527 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3528 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3529
3530 if (warn_on_failure) {
3531 char msg[128];
3532 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3533 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3534 warning("%s", msg);
3535 }
3536 }
3537
3538 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3539 char* req_addr,
3540 bool exec) {
3541 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3542 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3543 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3544
3545 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3546 char* addr = (char*)::mmap(req_addr, bytes, prot,
3547 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3548 -1, 0);
3549
3550 if (addr == MAP_FAILED) {
3551 warn_on_large_pages_failure(req_addr, bytes, errno);
3552 return NULL;
3553 }
3554
3555 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3556
3557 return addr;
3558 }
3559
3560 // Reserve memory using mmap(MAP_HUGETLB).
3561 // - bytes shall be a multiple of alignment.
3562 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3563 // - alignment sets the alignment at which memory shall be allocated.
3564 // It must be a multiple of allocation granularity.
3565 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3566 // req_addr or NULL.
3567 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3568 size_t alignment,
3569 char* req_addr,
3570 bool exec) {
3571 size_t large_page_size = os::large_page_size();
3572 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3573
3574 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3575 assert(is_size_aligned(bytes, alignment), "Must be");
3576
3577 // First reserve - but not commit - the address range in small pages.
3578 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3579
3580 if (start == NULL) {
3581 return NULL;
3582 }
3583
3584 assert(is_ptr_aligned(start, alignment), "Must be");
3585
3586 char* end = start + bytes;
3587
3588 // Find the regions of the allocated chunk that can be promoted to large pages.
3589 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3590 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3591
3592 size_t lp_bytes = lp_end - lp_start;
3593
3594 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3595
3596 if (lp_bytes == 0) {
3597 // The mapped region doesn't even span the start and the end of a large page.
3598 // Fall back to allocate a non-special area.
3599 ::munmap(start, end - start);
3600 return NULL;
3601 }
3602
3603 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3604
3605 void* result;
3606
3607 // Commit small-paged leading area.
3608 if (start != lp_start) {
3609 result = ::mmap(start, lp_start - start, prot,
3610 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3611 -1, 0);
3612 if (result == MAP_FAILED) {
3613 ::munmap(lp_start, end - lp_start);
3614 return NULL;
3615 }
3616 }
3617
3618 // Commit large-paged area.
3619 result = ::mmap(lp_start, lp_bytes, prot,
3620 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3621 -1, 0);
3622 if (result == MAP_FAILED) {
3623 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3624 // If the mmap above fails, the large pages region will be unmapped and we
3625 // have regions before and after with small pages. Release these regions.
3626 //
3627 // | mapped | unmapped | mapped |
3628 // ^ ^ ^ ^
3629 // start lp_start lp_end end
3630 //
3631 ::munmap(start, lp_start - start);
3632 ::munmap(lp_end, end - lp_end);
3633 return NULL;
3634 }
3635
3636 // Commit small-paged trailing area.
3637 if (lp_end != end) {
3638 result = ::mmap(lp_end, end - lp_end, prot,
3639 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3640 -1, 0);
3641 if (result == MAP_FAILED) {
3642 ::munmap(start, lp_end - start);
3643 return NULL;
3644 }
3645 }
3646
3647 return start;
3648 }
3649
3650 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3651 size_t alignment,
3652 char* req_addr,
3653 bool exec) {
3654 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3655 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3656 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3657 assert(is_power_of_2(os::large_page_size()), "Must be");
3658 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3659
3660 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3661 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3662 } else {
3663 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3664 }
3665 }
3666
3667 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3668 char* req_addr, bool exec) {
3669 assert(UseLargePages, "only for large pages");
3670
3671 char* addr;
3672 if (UseSHM) {
3673 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3674 } else {
3675 assert(UseHugeTLBFS, "must be");
3676 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3677 }
3678
3679 if (addr != NULL) {
3680 if (UseNUMAInterleaving) {
3681 numa_make_global(addr, bytes);
3682 }
3683
3684 // The memory is committed
3685 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3686 }
3687
3688 return addr;
3689 }
3690
3691 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3692 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3693 return shmdt(base) == 0;
3694 }
3695
3696 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3697 return pd_release_memory(base, bytes);
3698 }
3699
3700 bool os::release_memory_special(char* base, size_t bytes) {
3701 bool res;
3702 if (MemTracker::tracking_level() > NMT_minimal) {
3703 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3704 res = os::Linux::release_memory_special_impl(base, bytes);
3705 if (res) {
3706 tkr.record((address)base, bytes);
3707 }
3708
3709 } else {
3710 res = os::Linux::release_memory_special_impl(base, bytes);
3711 }
3712 return res;
3713 }
3714
3715 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3716 assert(UseLargePages, "only for large pages");
3717 bool res;
3718
3719 if (UseSHM) {
3720 res = os::Linux::release_memory_special_shm(base, bytes);
3721 } else {
3722 assert(UseHugeTLBFS, "must be");
3723 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3724 }
3725 return res;
3726 }
3727
3728 size_t os::large_page_size() {
3729 return _large_page_size;
3730 }
3731
3732 // With SysV SHM the entire memory region must be allocated as shared
3733 // memory.
3734 // HugeTLBFS allows application to commit large page memory on demand.
3735 // However, when committing memory with HugeTLBFS fails, the region
3736 // that was supposed to be committed will lose the old reservation
3737 // and allow other threads to steal that memory region. Because of this
3738 // behavior we can't commit HugeTLBFS memory.
3739 bool os::can_commit_large_page_memory() {
3740 return UseTransparentHugePages;
3741 }
3742
3743 bool os::can_execute_large_page_memory() {
3744 return UseTransparentHugePages || UseHugeTLBFS;
3745 }
3746
3747 // Reserve memory at an arbitrary address, only if that area is
3748 // available (and not reserved for something else).
3749
3750 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3751 const int max_tries = 10;
3752 char* base[max_tries];
3753 size_t size[max_tries];
3754 const size_t gap = 0x000000;
3755
3756 // Assert only that the size is a multiple of the page size, since
3757 // that's all that mmap requires, and since that's all we really know
3758 // about at this low abstraction level. If we need higher alignment,
3759 // we can either pass an alignment to this method or verify alignment
3760 // in one of the methods further up the call chain. See bug 5044738.
3761 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3762
3763 // Repeatedly allocate blocks until the block is allocated at the
3764 // right spot.
3765
3766 // Linux mmap allows caller to pass an address as hint; give it a try first,
3767 // if kernel honors the hint then we can return immediately.
3768 char * addr = anon_mmap(requested_addr, bytes, false);
3769 if (addr == requested_addr) {
3770 return requested_addr;
3771 }
3772
3773 if (addr != NULL) {
3774 // mmap() is successful but it fails to reserve at the requested address
3775 anon_munmap(addr, bytes);
3776 }
3777
3778 int i;
3779 for (i = 0; i < max_tries; ++i) {
3780 base[i] = reserve_memory(bytes);
3781
3782 if (base[i] != NULL) {
3783 // Is this the block we wanted?
3784 if (base[i] == requested_addr) {
3785 size[i] = bytes;
3786 break;
3787 }
3788
3789 // Does this overlap the block we wanted? Give back the overlapped
3790 // parts and try again.
3791
3792 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3793 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3794 unmap_memory(base[i], top_overlap);
3795 base[i] += top_overlap;
3796 size[i] = bytes - top_overlap;
3797 } else {
3798 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3799 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3800 unmap_memory(requested_addr, bottom_overlap);
3801 size[i] = bytes - bottom_overlap;
3802 } else {
3803 size[i] = bytes;
3804 }
3805 }
3806 }
3807 }
3808
3809 // Give back the unused reserved pieces.
3810
3811 for (int j = 0; j < i; ++j) {
3812 if (base[j] != NULL) {
3813 unmap_memory(base[j], size[j]);
3814 }
3815 }
3816
3817 if (i < max_tries) {
3818 return requested_addr;
3819 } else {
3820 return NULL;
3821 }
3822 }
3823
3824 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3825 return ::read(fd, buf, nBytes);
3826 }
3827
3828 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3829 return ::pread(fd, buf, nBytes, offset);
3830 }
3831
3832 // Short sleep, direct OS call.
3833 //
3834 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3835 // sched_yield(2) will actually give up the CPU:
3836 //
3837 // * Alone on this pariticular CPU, keeps running.
3838 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3839 // (pre 2.6.39).
3840 //
3841 // So calling this with 0 is an alternative.
3842 //
3843 void os::naked_short_sleep(jlong ms) {
3844 struct timespec req;
3845
3846 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3847 req.tv_sec = 0;
3848 if (ms > 0) {
3849 req.tv_nsec = (ms % 1000) * 1000000;
3850 } else {
3851 req.tv_nsec = 1;
3852 }
3853
3854 nanosleep(&req, NULL);
3855
3856 return;
3857 }
3858
3859 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3860 void os::infinite_sleep() {
3861 while (true) { // sleep forever ...
3862 ::sleep(100); // ... 100 seconds at a time
3863 }
3864 }
3865
3866 // Used to convert frequent JVM_Yield() to nops
3867 bool os::dont_yield() {
3868 return DontYieldALot;
3869 }
3870
3871 void os::naked_yield() {
3872 sched_yield();
3873 }
3874
3875 ////////////////////////////////////////////////////////////////////////////////
3876 // thread priority support
3877
3878 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3879 // only supports dynamic priority, static priority must be zero. For real-time
3880 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3881 // However, for large multi-threaded applications, SCHED_RR is not only slower
3882 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3883 // of 5 runs - Sep 2005).
3884 //
3885 // The following code actually changes the niceness of kernel-thread/LWP. It
3886 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3887 // not the entire user process, and user level threads are 1:1 mapped to kernel
3888 // threads. It has always been the case, but could change in the future. For
3889 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3890 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3891
3892 int os::java_to_os_priority[CriticalPriority + 1] = {
3893 19, // 0 Entry should never be used
3894
3895 4, // 1 MinPriority
3896 3, // 2
3897 2, // 3
3898
3899 1, // 4
3900 0, // 5 NormPriority
3901 -1, // 6
3902
3903 -2, // 7
3904 -3, // 8
3905 -4, // 9 NearMaxPriority
3906
3907 -5, // 10 MaxPriority
3908
3909 -5 // 11 CriticalPriority
3910 };
3911
3912 static int prio_init() {
3913 if (ThreadPriorityPolicy == 1) {
3914 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3915 // if effective uid is not root. Perhaps, a more elegant way of doing
3916 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3917 if (geteuid() != 0) {
3918 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3919 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3920 }
3921 ThreadPriorityPolicy = 0;
3922 }
3923 }
3924 if (UseCriticalJavaThreadPriority) {
3925 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3926 }
3927 return 0;
3928 }
3929
3930 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3931 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3932
3933 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3934 return (ret == 0) ? OS_OK : OS_ERR;
3935 }
3936
3937 OSReturn os::get_native_priority(const Thread* const thread,
3938 int *priority_ptr) {
3939 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3940 *priority_ptr = java_to_os_priority[NormPriority];
3941 return OS_OK;
3942 }
3943
3944 errno = 0;
3945 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3946 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3947 }
3948
3949 // Hint to the underlying OS that a task switch would not be good.
3950 // Void return because it's a hint and can fail.
3951 void os::hint_no_preempt() {}
3952
3953 ////////////////////////////////////////////////////////////////////////////////
3954 // suspend/resume support
3955
3956 // the low-level signal-based suspend/resume support is a remnant from the
3957 // old VM-suspension that used to be for java-suspension, safepoints etc,
3958 // within hotspot. Now there is a single use-case for this:
3959 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3960 // that runs in the watcher thread.
3961 // The remaining code is greatly simplified from the more general suspension
3962 // code that used to be used.
3963 //
3964 // The protocol is quite simple:
3965 // - suspend:
3966 // - sends a signal to the target thread
3967 // - polls the suspend state of the osthread using a yield loop
3968 // - target thread signal handler (SR_handler) sets suspend state
3969 // and blocks in sigsuspend until continued
3970 // - resume:
3971 // - sets target osthread state to continue
3972 // - sends signal to end the sigsuspend loop in the SR_handler
3973 //
3974 // Note that the SR_lock plays no role in this suspend/resume protocol,
3975 // but is checked for NULL in SR_handler as a thread termination indicator.
3976
3977 static void resume_clear_context(OSThread *osthread) {
3978 osthread->set_ucontext(NULL);
3979 osthread->set_siginfo(NULL);
3980 }
3981
3982 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
3983 ucontext_t* context) {
3984 osthread->set_ucontext(context);
3985 osthread->set_siginfo(siginfo);
3986 }
3987
3988 // Handler function invoked when a thread's execution is suspended or
3989 // resumed. We have to be careful that only async-safe functions are
3990 // called here (Note: most pthread functions are not async safe and
3991 // should be avoided.)
3992 //
3993 // Note: sigwait() is a more natural fit than sigsuspend() from an
3994 // interface point of view, but sigwait() prevents the signal hander
3995 // from being run. libpthread would get very confused by not having
3996 // its signal handlers run and prevents sigwait()'s use with the
3997 // mutex granting granting signal.
3998 //
3999 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4000 //
4001 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4002 // Save and restore errno to avoid confusing native code with EINTR
4003 // after sigsuspend.
4004 int old_errno = errno;
4005
4006 Thread* thread = Thread::current_or_null_safe();
4007 assert(thread != NULL, "Missing current thread in SR_handler");
4008
4009 // On some systems we have seen signal delivery get "stuck" until the signal
4010 // mask is changed as part of thread termination. Check that the current thread
4011 // has not already terminated (via SR_lock()) - else the following assertion
4012 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4013 // destructor has completed.
4014
4015 if (thread->SR_lock() == NULL) {
4016 return;
4017 }
4018
4019 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4020
4021 OSThread* osthread = thread->osthread();
4022
4023 os::SuspendResume::State current = osthread->sr.state();
4024 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4025 suspend_save_context(osthread, siginfo, context);
4026
4027 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4028 os::SuspendResume::State state = osthread->sr.suspended();
4029 if (state == os::SuspendResume::SR_SUSPENDED) {
4030 sigset_t suspend_set; // signals for sigsuspend()
4031 sigemptyset(&suspend_set);
4032 // get current set of blocked signals and unblock resume signal
4033 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4034 sigdelset(&suspend_set, SR_signum);
4035
4036 sr_semaphore.signal();
4037 // wait here until we are resumed
4038 while (1) {
4039 sigsuspend(&suspend_set);
4040
4041 os::SuspendResume::State result = osthread->sr.running();
4042 if (result == os::SuspendResume::SR_RUNNING) {
4043 sr_semaphore.signal();
4044 break;
4045 }
4046 }
4047
4048 } else if (state == os::SuspendResume::SR_RUNNING) {
4049 // request was cancelled, continue
4050 } else {
4051 ShouldNotReachHere();
4052 }
4053
4054 resume_clear_context(osthread);
4055 } else if (current == os::SuspendResume::SR_RUNNING) {
4056 // request was cancelled, continue
4057 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4058 // ignore
4059 } else {
4060 // ignore
4061 }
4062
4063 errno = old_errno;
4064 }
4065
4066 static int SR_initialize() {
4067 struct sigaction act;
4068 char *s;
4069
4070 // Get signal number to use for suspend/resume
4071 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4072 int sig = ::strtol(s, 0, 10);
4073 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4074 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4075 SR_signum = sig;
4076 } else {
4077 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4078 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4079 }
4080 }
4081
4082 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4083 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4084
4085 sigemptyset(&SR_sigset);
4086 sigaddset(&SR_sigset, SR_signum);
4087
4088 // Set up signal handler for suspend/resume
4089 act.sa_flags = SA_RESTART|SA_SIGINFO;
4090 act.sa_handler = (void (*)(int)) SR_handler;
4091
4092 // SR_signum is blocked by default.
4093 // 4528190 - We also need to block pthread restart signal (32 on all
4094 // supported Linux platforms). Note that LinuxThreads need to block
4095 // this signal for all threads to work properly. So we don't have
4096 // to use hard-coded signal number when setting up the mask.
4097 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4098
4099 if (sigaction(SR_signum, &act, 0) == -1) {
4100 return -1;
4101 }
4102
4103 // Save signal flag
4104 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4105 return 0;
4106 }
4107
4108 static int sr_notify(OSThread* osthread) {
4109 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4110 assert_status(status == 0, status, "pthread_kill");
4111 return status;
4112 }
4113
4114 // "Randomly" selected value for how long we want to spin
4115 // before bailing out on suspending a thread, also how often
4116 // we send a signal to a thread we want to resume
4117 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4118 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4119
4120 // returns true on success and false on error - really an error is fatal
4121 // but this seems the normal response to library errors
4122 static bool do_suspend(OSThread* osthread) {
4123 assert(osthread->sr.is_running(), "thread should be running");
4124 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4125
4126 // mark as suspended and send signal
4127 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4128 // failed to switch, state wasn't running?
4129 ShouldNotReachHere();
4130 return false;
4131 }
4132
4133 if (sr_notify(osthread) != 0) {
4134 ShouldNotReachHere();
4135 }
4136
4137 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4138 while (true) {
4139 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4140 break;
4141 } else {
4142 // timeout
4143 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4144 if (cancelled == os::SuspendResume::SR_RUNNING) {
4145 return false;
4146 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4147 // make sure that we consume the signal on the semaphore as well
4148 sr_semaphore.wait();
4149 break;
4150 } else {
4151 ShouldNotReachHere();
4152 return false;
4153 }
4154 }
4155 }
4156
4157 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4158 return true;
4159 }
4160
4161 static void do_resume(OSThread* osthread) {
4162 assert(osthread->sr.is_suspended(), "thread should be suspended");
4163 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4164
4165 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4166 // failed to switch to WAKEUP_REQUEST
4167 ShouldNotReachHere();
4168 return;
4169 }
4170
4171 while (true) {
4172 if (sr_notify(osthread) == 0) {
4173 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4174 if (osthread->sr.is_running()) {
4175 return;
4176 }
4177 }
4178 } else {
4179 ShouldNotReachHere();
4180 }
4181 }
4182
4183 guarantee(osthread->sr.is_running(), "Must be running!");
4184 }
4185
4186 ///////////////////////////////////////////////////////////////////////////////////
4187 // signal handling (except suspend/resume)
4188
4189 // This routine may be used by user applications as a "hook" to catch signals.
4190 // The user-defined signal handler must pass unrecognized signals to this
4191 // routine, and if it returns true (non-zero), then the signal handler must
4192 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4193 // routine will never retun false (zero), but instead will execute a VM panic
4194 // routine kill the process.
4195 //
4196 // If this routine returns false, it is OK to call it again. This allows
4197 // the user-defined signal handler to perform checks either before or after
4198 // the VM performs its own checks. Naturally, the user code would be making
4199 // a serious error if it tried to handle an exception (such as a null check
4200 // or breakpoint) that the VM was generating for its own correct operation.
4201 //
4202 // This routine may recognize any of the following kinds of signals:
4203 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4204 // It should be consulted by handlers for any of those signals.
4205 //
4206 // The caller of this routine must pass in the three arguments supplied
4207 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4208 // field of the structure passed to sigaction(). This routine assumes that
4209 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4210 //
4211 // Note that the VM will print warnings if it detects conflicting signal
4212 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4213 //
4214 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4215 siginfo_t* siginfo,
4216 void* ucontext,
4217 int abort_if_unrecognized);
4218
4219 void signalHandler(int sig, siginfo_t* info, void* uc) {
4220 assert(info != NULL && uc != NULL, "it must be old kernel");
4221 int orig_errno = errno; // Preserve errno value over signal handler.
4222 JVM_handle_linux_signal(sig, info, uc, true);
4223 errno = orig_errno;
4224 }
4225
4226
4227 // This boolean allows users to forward their own non-matching signals
4228 // to JVM_handle_linux_signal, harmlessly.
4229 bool os::Linux::signal_handlers_are_installed = false;
4230
4231 // For signal-chaining
4232 struct sigaction sigact[NSIG];
4233 uint64_t sigs = 0;
4234 #if (64 < NSIG-1)
4235 #error "Not all signals can be encoded in sigs. Adapt its type!"
4236 #endif
4237 bool os::Linux::libjsig_is_loaded = false;
4238 typedef struct sigaction *(*get_signal_t)(int);
4239 get_signal_t os::Linux::get_signal_action = NULL;
4240
4241 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4242 struct sigaction *actp = NULL;
4243
4244 if (libjsig_is_loaded) {
4245 // Retrieve the old signal handler from libjsig
4246 actp = (*get_signal_action)(sig);
4247 }
4248 if (actp == NULL) {
4249 // Retrieve the preinstalled signal handler from jvm
4250 actp = get_preinstalled_handler(sig);
4251 }
4252
4253 return actp;
4254 }
4255
4256 static bool call_chained_handler(struct sigaction *actp, int sig,
4257 siginfo_t *siginfo, void *context) {
4258 // Call the old signal handler
4259 if (actp->sa_handler == SIG_DFL) {
4260 // It's more reasonable to let jvm treat it as an unexpected exception
4261 // instead of taking the default action.
4262 return false;
4263 } else if (actp->sa_handler != SIG_IGN) {
4264 if ((actp->sa_flags & SA_NODEFER) == 0) {
4265 // automaticlly block the signal
4266 sigaddset(&(actp->sa_mask), sig);
4267 }
4268
4269 sa_handler_t hand = NULL;
4270 sa_sigaction_t sa = NULL;
4271 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4272 // retrieve the chained handler
4273 if (siginfo_flag_set) {
4274 sa = actp->sa_sigaction;
4275 } else {
4276 hand = actp->sa_handler;
4277 }
4278
4279 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4280 actp->sa_handler = SIG_DFL;
4281 }
4282
4283 // try to honor the signal mask
4284 sigset_t oset;
4285 sigemptyset(&oset);
4286 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4287
4288 // call into the chained handler
4289 if (siginfo_flag_set) {
4290 (*sa)(sig, siginfo, context);
4291 } else {
4292 (*hand)(sig);
4293 }
4294
4295 // restore the signal mask
4296 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4297 }
4298 // Tell jvm's signal handler the signal is taken care of.
4299 return true;
4300 }
4301
4302 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4303 bool chained = false;
4304 // signal-chaining
4305 if (UseSignalChaining) {
4306 struct sigaction *actp = get_chained_signal_action(sig);
4307 if (actp != NULL) {
4308 chained = call_chained_handler(actp, sig, siginfo, context);
4309 }
4310 }
4311 return chained;
4312 }
4313
4314 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4315 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4316 return &sigact[sig];
4317 }
4318 return NULL;
4319 }
4320
4321 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4322 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4323 sigact[sig] = oldAct;
4324 sigs |= (uint64_t)1 << (sig-1);
4325 }
4326
4327 // for diagnostic
4328 int sigflags[NSIG];
4329
4330 int os::Linux::get_our_sigflags(int sig) {
4331 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4332 return sigflags[sig];
4333 }
4334
4335 void os::Linux::set_our_sigflags(int sig, int flags) {
4336 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4337 if (sig > 0 && sig < NSIG) {
4338 sigflags[sig] = flags;
4339 }
4340 }
4341
4342 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4343 // Check for overwrite.
4344 struct sigaction oldAct;
4345 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4346
4347 void* oldhand = oldAct.sa_sigaction
4348 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4349 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4350 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4351 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4352 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4353 if (AllowUserSignalHandlers || !set_installed) {
4354 // Do not overwrite; user takes responsibility to forward to us.
4355 return;
4356 } else if (UseSignalChaining) {
4357 // save the old handler in jvm
4358 save_preinstalled_handler(sig, oldAct);
4359 // libjsig also interposes the sigaction() call below and saves the
4360 // old sigaction on it own.
4361 } else {
4362 fatal("Encountered unexpected pre-existing sigaction handler "
4363 "%#lx for signal %d.", (long)oldhand, sig);
4364 }
4365 }
4366
4367 struct sigaction sigAct;
4368 sigfillset(&(sigAct.sa_mask));
4369 sigAct.sa_handler = SIG_DFL;
4370 if (!set_installed) {
4371 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4372 } else {
4373 sigAct.sa_sigaction = signalHandler;
4374 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4375 }
4376 // Save flags, which are set by ours
4377 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4378 sigflags[sig] = sigAct.sa_flags;
4379
4380 int ret = sigaction(sig, &sigAct, &oldAct);
4381 assert(ret == 0, "check");
4382
4383 void* oldhand2 = oldAct.sa_sigaction
4384 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4385 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4386 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4387 }
4388
4389 // install signal handlers for signals that HotSpot needs to
4390 // handle in order to support Java-level exception handling.
4391
4392 void os::Linux::install_signal_handlers() {
4393 if (!signal_handlers_are_installed) {
4394 signal_handlers_are_installed = true;
4395
4396 // signal-chaining
4397 typedef void (*signal_setting_t)();
4398 signal_setting_t begin_signal_setting = NULL;
4399 signal_setting_t end_signal_setting = NULL;
4400 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4401 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4402 if (begin_signal_setting != NULL) {
4403 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4404 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4405 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4406 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4407 libjsig_is_loaded = true;
4408 assert(UseSignalChaining, "should enable signal-chaining");
4409 }
4410 if (libjsig_is_loaded) {
4411 // Tell libjsig jvm is setting signal handlers
4412 (*begin_signal_setting)();
4413 }
4414
4415 set_signal_handler(SIGSEGV, true);
4416 set_signal_handler(SIGPIPE, true);
4417 set_signal_handler(SIGBUS, true);
4418 set_signal_handler(SIGILL, true);
4419 set_signal_handler(SIGFPE, true);
4420 #if defined(PPC64)
4421 set_signal_handler(SIGTRAP, true);
4422 #endif
4423 set_signal_handler(SIGXFSZ, true);
4424
4425 if (libjsig_is_loaded) {
4426 // Tell libjsig jvm finishes setting signal handlers
4427 (*end_signal_setting)();
4428 }
4429
4430 // We don't activate signal checker if libjsig is in place, we trust ourselves
4431 // and if UserSignalHandler is installed all bets are off.
4432 // Log that signal checking is off only if -verbose:jni is specified.
4433 if (CheckJNICalls) {
4434 if (libjsig_is_loaded) {
4435 if (PrintJNIResolving) {
4436 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4437 }
4438 check_signals = false;
4439 }
4440 if (AllowUserSignalHandlers) {
4441 if (PrintJNIResolving) {
4442 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4443 }
4444 check_signals = false;
4445 }
4446 }
4447 }
4448 }
4449
4450 // This is the fastest way to get thread cpu time on Linux.
4451 // Returns cpu time (user+sys) for any thread, not only for current.
4452 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4453 // It might work on 2.6.10+ with a special kernel/glibc patch.
4454 // For reference, please, see IEEE Std 1003.1-2004:
4455 // http://www.unix.org/single_unix_specification
4456
4457 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4458 struct timespec tp;
4459 int rc = os::Linux::clock_gettime(clockid, &tp);
4460 assert(rc == 0, "clock_gettime is expected to return 0 code");
4461
4462 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4463 }
4464
4465 void os::Linux::initialize_os_info() {
4466 assert(_os_version == 0, "OS info already initialized");
4467
4468 struct utsname _uname;
4469
4470 uint32_t major;
4471 uint32_t minor;
4472 uint32_t fix;
4473
4474 int rc;
4475
4476 // Kernel version is unknown if
4477 // verification below fails.
4478 _os_version = 0x01000000;
4479
4480 rc = uname(&_uname);
4481 if (rc != -1) {
4482
4483 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4484 if (rc == 3) {
4485
4486 if (major < 256 && minor < 256 && fix < 256) {
4487 // Kernel version format is as expected,
4488 // set it overriding unknown state.
4489 _os_version = (major << 16) |
4490 (minor << 8 ) |
4491 (fix << 0 ) ;
4492 }
4493 }
4494 }
4495 }
4496
4497 uint32_t os::Linux::os_version() {
4498 assert(_os_version != 0, "not initialized");
4499 return _os_version & 0x00FFFFFF;
4500 }
4501
4502 bool os::Linux::os_version_is_known() {
4503 assert(_os_version != 0, "not initialized");
4504 return _os_version & 0x01000000 ? false : true;
4505 }
4506
4507 /////
4508 // glibc on Linux platform uses non-documented flag
4509 // to indicate, that some special sort of signal
4510 // trampoline is used.
4511 // We will never set this flag, and we should
4512 // ignore this flag in our diagnostic
4513 #ifdef SIGNIFICANT_SIGNAL_MASK
4514 #undef SIGNIFICANT_SIGNAL_MASK
4515 #endif
4516 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4517
4518 static const char* get_signal_handler_name(address handler,
4519 char* buf, int buflen) {
4520 int offset = 0;
4521 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4522 if (found) {
4523 // skip directory names
4524 const char *p1, *p2;
4525 p1 = buf;
4526 size_t len = strlen(os::file_separator());
4527 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4528 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4529 } else {
4530 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4531 }
4532 return buf;
4533 }
4534
4535 static void print_signal_handler(outputStream* st, int sig,
4536 char* buf, size_t buflen) {
4537 struct sigaction sa;
4538
4539 sigaction(sig, NULL, &sa);
4540
4541 // See comment for SIGNIFICANT_SIGNAL_MASK define
4542 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4543
4544 st->print("%s: ", os::exception_name(sig, buf, buflen));
4545
4546 address handler = (sa.sa_flags & SA_SIGINFO)
4547 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4548 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4549
4550 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4551 st->print("SIG_DFL");
4552 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4553 st->print("SIG_IGN");
4554 } else {
4555 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4556 }
4557
4558 st->print(", sa_mask[0]=");
4559 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4560
4561 address rh = VMError::get_resetted_sighandler(sig);
4562 // May be, handler was resetted by VMError?
4563 if (rh != NULL) {
4564 handler = rh;
4565 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4566 }
4567
4568 st->print(", sa_flags=");
4569 os::Posix::print_sa_flags(st, sa.sa_flags);
4570
4571 // Check: is it our handler?
4572 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4573 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4574 // It is our signal handler
4575 // check for flags, reset system-used one!
4576 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4577 st->print(
4578 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4579 os::Linux::get_our_sigflags(sig));
4580 }
4581 }
4582 st->cr();
4583 }
4584
4585
4586 #define DO_SIGNAL_CHECK(sig) \
4587 do { \
4588 if (!sigismember(&check_signal_done, sig)) { \
4589 os::Linux::check_signal_handler(sig); \
4590 } \
4591 } while (0)
4592
4593 // This method is a periodic task to check for misbehaving JNI applications
4594 // under CheckJNI, we can add any periodic checks here
4595
4596 void os::run_periodic_checks() {
4597 if (check_signals == false) return;
4598
4599 // SEGV and BUS if overridden could potentially prevent
4600 // generation of hs*.log in the event of a crash, debugging
4601 // such a case can be very challenging, so we absolutely
4602 // check the following for a good measure:
4603 DO_SIGNAL_CHECK(SIGSEGV);
4604 DO_SIGNAL_CHECK(SIGILL);
4605 DO_SIGNAL_CHECK(SIGFPE);
4606 DO_SIGNAL_CHECK(SIGBUS);
4607 DO_SIGNAL_CHECK(SIGPIPE);
4608 DO_SIGNAL_CHECK(SIGXFSZ);
4609 #if defined(PPC64)
4610 DO_SIGNAL_CHECK(SIGTRAP);
4611 #endif
4612
4613 // ReduceSignalUsage allows the user to override these handlers
4614 // see comments at the very top and jvm_solaris.h
4615 if (!ReduceSignalUsage) {
4616 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4617 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4618 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4619 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4620 }
4621
4622 DO_SIGNAL_CHECK(SR_signum);
4623 }
4624
4625 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4626
4627 static os_sigaction_t os_sigaction = NULL;
4628
4629 void os::Linux::check_signal_handler(int sig) {
4630 char buf[O_BUFLEN];
4631 address jvmHandler = NULL;
4632
4633
4634 struct sigaction act;
4635 if (os_sigaction == NULL) {
4636 // only trust the default sigaction, in case it has been interposed
4637 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4638 if (os_sigaction == NULL) return;
4639 }
4640
4641 os_sigaction(sig, (struct sigaction*)NULL, &act);
4642
4643
4644 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4645
4646 address thisHandler = (act.sa_flags & SA_SIGINFO)
4647 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4648 : CAST_FROM_FN_PTR(address, act.sa_handler);
4649
4650
4651 switch (sig) {
4652 case SIGSEGV:
4653 case SIGBUS:
4654 case SIGFPE:
4655 case SIGPIPE:
4656 case SIGILL:
4657 case SIGXFSZ:
4658 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4659 break;
4660
4661 case SHUTDOWN1_SIGNAL:
4662 case SHUTDOWN2_SIGNAL:
4663 case SHUTDOWN3_SIGNAL:
4664 case BREAK_SIGNAL:
4665 jvmHandler = (address)user_handler();
4666 break;
4667
4668 default:
4669 if (sig == SR_signum) {
4670 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4671 } else {
4672 return;
4673 }
4674 break;
4675 }
4676
4677 if (thisHandler != jvmHandler) {
4678 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4679 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4680 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4681 // No need to check this sig any longer
4682 sigaddset(&check_signal_done, sig);
4683 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4684 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4685 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4686 exception_name(sig, buf, O_BUFLEN));
4687 }
4688 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4689 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4690 tty->print("expected:");
4691 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4692 tty->cr();
4693 tty->print(" found:");
4694 os::Posix::print_sa_flags(tty, act.sa_flags);
4695 tty->cr();
4696 // No need to check this sig any longer
4697 sigaddset(&check_signal_done, sig);
4698 }
4699
4700 // Dump all the signal
4701 if (sigismember(&check_signal_done, sig)) {
4702 print_signal_handlers(tty, buf, O_BUFLEN);
4703 }
4704 }
4705
4706 extern void report_error(char* file_name, int line_no, char* title,
4707 char* format, ...);
4708
4709 // this is called _before_ the most of global arguments have been parsed
4710 void os::init(void) {
4711 char dummy; // used to get a guess on initial stack address
4712 // first_hrtime = gethrtime();
4713
4714 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4715
4716 init_random(1234567);
4717
4718 ThreadCritical::initialize();
4719
4720 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4721 if (Linux::page_size() == -1) {
4722 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4723 os::strerror(errno));
4724 }
4725 init_page_sizes((size_t) Linux::page_size());
4726
4727 Linux::initialize_system_info();
4728
4729 Linux::initialize_os_info();
4730
4731 // main_thread points to the aboriginal thread
4732 Linux::_main_thread = pthread_self();
4733
4734 Linux::clock_init();
4735 initial_time_count = javaTimeNanos();
4736
4737 // retrieve entry point for pthread_setname_np
4738 Linux::_pthread_setname_np =
4739 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4740
4741 os::Posix::init();
4742 }
4743
4744 // To install functions for atexit system call
4745 extern "C" {
4746 static void perfMemory_exit_helper() {
4747 perfMemory_exit();
4748 }
4749 }
4750
4751 // this is called _after_ the global arguments have been parsed
4752 jint os::init_2(void) {
4753
4754 os::Posix::init_2();
4755
4756 Linux::fast_thread_clock_init();
4757
4758 // Allocate a single page and mark it as readable for safepoint polling
4759 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4760 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4761
4762 os::set_polling_page(polling_page);
4763 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4764
4765 if (!UseMembar) {
4766 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4767 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4768 os::set_memory_serialize_page(mem_serialize_page);
4769 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4770 }
4771
4772 // initialize suspend/resume support - must do this before signal_sets_init()
4773 if (SR_initialize() != 0) {
4774 perror("SR_initialize failed");
4775 return JNI_ERR;
4776 }
4777
4778 Linux::signal_sets_init();
4779 Linux::install_signal_handlers();
4780
4781 // Check and sets minimum stack sizes against command line options
4782 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
4783 return JNI_ERR;
4784 }
4785 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4786
4787 #if defined(IA32)
4788 workaround_expand_exec_shield_cs_limit();
4789 #endif
4790
4791 Linux::libpthread_init();
4792 log_info(os)("HotSpot is running with %s, %s",
4793 Linux::glibc_version(), Linux::libpthread_version());
4794
4795 if (UseNUMA) {
4796 if (!Linux::libnuma_init()) {
4797 UseNUMA = false;
4798 } else {
4799 if ((Linux::numa_max_node() < 1)) {
4800 // There's only one node(they start from 0), disable NUMA.
4801 UseNUMA = false;
4802 }
4803 }
4804 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4805 // we can make the adaptive lgrp chunk resizing work. If the user specified
4806 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4807 // disable adaptive resizing.
4808 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4809 if (FLAG_IS_DEFAULT(UseNUMA)) {
4810 UseNUMA = false;
4811 } else {
4812 if (FLAG_IS_DEFAULT(UseLargePages) &&
4813 FLAG_IS_DEFAULT(UseSHM) &&
4814 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4815 UseLargePages = false;
4816 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4817 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4818 UseAdaptiveSizePolicy = false;
4819 UseAdaptiveNUMAChunkSizing = false;
4820 }
4821 }
4822 }
4823 if (!UseNUMA && ForceNUMA) {
4824 UseNUMA = true;
4825 }
4826 }
4827
4828 if (MaxFDLimit) {
4829 // set the number of file descriptors to max. print out error
4830 // if getrlimit/setrlimit fails but continue regardless.
4831 struct rlimit nbr_files;
4832 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4833 if (status != 0) {
4834 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4835 } else {
4836 nbr_files.rlim_cur = nbr_files.rlim_max;
4837 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4838 if (status != 0) {
4839 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4840 }
4841 }
4842 }
4843
4844 // Initialize lock used to serialize thread creation (see os::create_thread)
4845 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4846
4847 // at-exit methods are called in the reverse order of their registration.
4848 // atexit functions are called on return from main or as a result of a
4849 // call to exit(3C). There can be only 32 of these functions registered
4850 // and atexit() does not set errno.
4851
4852 if (PerfAllowAtExitRegistration) {
4853 // only register atexit functions if PerfAllowAtExitRegistration is set.
4854 // atexit functions can be delayed until process exit time, which
4855 // can be problematic for embedded VM situations. Embedded VMs should
4856 // call DestroyJavaVM() to assure that VM resources are released.
4857
4858 // note: perfMemory_exit_helper atexit function may be removed in
4859 // the future if the appropriate cleanup code can be added to the
4860 // VM_Exit VMOperation's doit method.
4861 if (atexit(perfMemory_exit_helper) != 0) {
4862 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4863 }
4864 }
4865
4866 // initialize thread priority policy
4867 prio_init();
4868
4869 return JNI_OK;
4870 }
4871
4872 // Mark the polling page as unreadable
4873 void os::make_polling_page_unreadable(void) {
4874 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4875 fatal("Could not disable polling page");
4876 }
4877 }
4878
4879 // Mark the polling page as readable
4880 void os::make_polling_page_readable(void) {
4881 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4882 fatal("Could not enable polling page");
4883 }
4884 }
4885
4886 // older glibc versions don't have this macro (which expands to
4887 // an optimized bit-counting function) so we have to roll our own
4888 #ifndef CPU_COUNT
4889
4890 static int _cpu_count(const cpu_set_t* cpus) {
4891 int count = 0;
4892 // only look up to the number of configured processors
4893 for (int i = 0; i < os::processor_count(); i++) {
4894 if (CPU_ISSET(i, cpus)) {
4895 count++;
4896 }
4897 }
4898 return count;
4899 }
4900
4901 #define CPU_COUNT(cpus) _cpu_count(cpus)
4902
4903 #endif // CPU_COUNT
4904
4905 // Get the current number of available processors for this process.
4906 // This value can change at any time during a process's lifetime.
4907 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4908 // If it appears there may be more than 1024 processors then we do a
4909 // dynamic check - see 6515172 for details.
4910 // If anything goes wrong we fallback to returning the number of online
4911 // processors - which can be greater than the number available to the process.
4912 int os::active_processor_count() {
4913 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4914 cpu_set_t* cpus_p = &cpus;
4915 int cpus_size = sizeof(cpu_set_t);
4916
4917 int configured_cpus = processor_count(); // upper bound on available cpus
4918 int cpu_count = 0;
4919
4920 // old build platforms may not support dynamic cpu sets
4921 #ifdef CPU_ALLOC
4922
4923 // To enable easy testing of the dynamic path on different platforms we
4924 // introduce a diagnostic flag: UseCpuAllocPath
4925 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4926 // kernel may use a mask bigger than cpu_set_t
4927 log_trace(os)("active_processor_count: using dynamic path %s"
4928 "- configured processors: %d",
4929 UseCpuAllocPath ? "(forced) " : "",
4930 configured_cpus);
4931 cpus_p = CPU_ALLOC(configured_cpus);
4932 if (cpus_p != NULL) {
4933 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4934 // zero it just to be safe
4935 CPU_ZERO_S(cpus_size, cpus_p);
4936 }
4937 else {
4938 // failed to allocate so fallback to online cpus
4939 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4940 log_trace(os)("active_processor_count: "
4941 "CPU_ALLOC failed (%s) - using "
4942 "online processor count: %d",
4943 os::strerror(errno), online_cpus);
4944 return online_cpus;
4945 }
4946 }
4947 else {
4948 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4949 configured_cpus);
4950 }
4951 #else // CPU_ALLOC
4952 // these stubs won't be executed
4953 #define CPU_COUNT_S(size, cpus) -1
4954 #define CPU_FREE(cpus)
4955
4956 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4957 configured_cpus);
4958 #endif // CPU_ALLOC
4959
4960 // pid 0 means the current thread - which we have to assume represents the process
4961 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4962 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4963 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4964 }
4965 else {
4966 cpu_count = CPU_COUNT(cpus_p);
4967 }
4968 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
4969 }
4970 else {
4971 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
4972 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
4973 "which may exceed available processors", os::strerror(errno), cpu_count);
4974 }
4975
4976 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4977 CPU_FREE(cpus_p);
4978 }
4979
4980 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
4981 return cpu_count;
4982 }
4983
4984 void os::set_native_thread_name(const char *name) {
4985 if (Linux::_pthread_setname_np) {
4986 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
4987 snprintf(buf, sizeof(buf), "%s", name);
4988 buf[sizeof(buf) - 1] = '\0';
4989 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
4990 // ERANGE should not happen; all other errors should just be ignored.
4991 assert(rc != ERANGE, "pthread_setname_np failed");
4992 }
4993 }
4994
4995 bool os::distribute_processes(uint length, uint* distribution) {
4996 // Not yet implemented.
4997 return false;
4998 }
4999
5000 bool os::bind_to_processor(uint processor_id) {
5001 // Not yet implemented.
5002 return false;
5003 }
5004
5005 ///
5006
5007 void os::SuspendedThreadTask::internal_do_task() {
5008 if (do_suspend(_thread->osthread())) {
5009 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5010 do_task(context);
5011 do_resume(_thread->osthread());
5012 }
5013 }
5014
5015 class PcFetcher : public os::SuspendedThreadTask {
5016 public:
5017 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5018 ExtendedPC result();
5019 protected:
5020 void do_task(const os::SuspendedThreadTaskContext& context);
5021 private:
5022 ExtendedPC _epc;
5023 };
5024
5025 ExtendedPC PcFetcher::result() {
5026 guarantee(is_done(), "task is not done yet.");
5027 return _epc;
5028 }
5029
5030 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5031 Thread* thread = context.thread();
5032 OSThread* osthread = thread->osthread();
5033 if (osthread->ucontext() != NULL) {
5034 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5035 } else {
5036 // NULL context is unexpected, double-check this is the VMThread
5037 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5038 }
5039 }
5040
5041 // Suspends the target using the signal mechanism and then grabs the PC before
5042 // resuming the target. Used by the flat-profiler only
5043 ExtendedPC os::get_thread_pc(Thread* thread) {
5044 // Make sure that it is called by the watcher for the VMThread
5045 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5046 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5047
5048 PcFetcher fetcher(thread);
5049 fetcher.run();
5050 return fetcher.result();
5051 }
5052
5053 ////////////////////////////////////////////////////////////////////////////////
5054 // debug support
5055
5056 bool os::find(address addr, outputStream* st) {
5057 Dl_info dlinfo;
5058 memset(&dlinfo, 0, sizeof(dlinfo));
5059 if (dladdr(addr, &dlinfo) != 0) {
5060 st->print(PTR_FORMAT ": ", p2i(addr));
5061 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5062 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5063 p2i(addr) - p2i(dlinfo.dli_saddr));
5064 } else if (dlinfo.dli_fbase != NULL) {
5065 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5066 } else {
5067 st->print("<absolute address>");
5068 }
5069 if (dlinfo.dli_fname != NULL) {
5070 st->print(" in %s", dlinfo.dli_fname);
5071 }
5072 if (dlinfo.dli_fbase != NULL) {
5073 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5074 }
5075 st->cr();
5076
5077 if (Verbose) {
5078 // decode some bytes around the PC
5079 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5080 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5081 address lowest = (address) dlinfo.dli_sname;
5082 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5083 if (begin < lowest) begin = lowest;
5084 Dl_info dlinfo2;
5085 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5086 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5087 end = (address) dlinfo2.dli_saddr;
5088 }
5089 Disassembler::decode(begin, end, st);
5090 }
5091 return true;
5092 }
5093 return false;
5094 }
5095
5096 ////////////////////////////////////////////////////////////////////////////////
5097 // misc
5098
5099 // This does not do anything on Linux. This is basically a hook for being
5100 // able to use structured exception handling (thread-local exception filters)
5101 // on, e.g., Win32.
5102 void
5103 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5104 JavaCallArguments* args, Thread* thread) {
5105 f(value, method, args, thread);
5106 }
5107
5108 void os::print_statistics() {
5109 }
5110
5111 bool os::message_box(const char* title, const char* message) {
5112 int i;
5113 fdStream err(defaultStream::error_fd());
5114 for (i = 0; i < 78; i++) err.print_raw("=");
5115 err.cr();
5116 err.print_raw_cr(title);
5117 for (i = 0; i < 78; i++) err.print_raw("-");
5118 err.cr();
5119 err.print_raw_cr(message);
5120 for (i = 0; i < 78; i++) err.print_raw("=");
5121 err.cr();
5122
5123 char buf[16];
5124 // Prevent process from exiting upon "read error" without consuming all CPU
5125 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5126
5127 return buf[0] == 'y' || buf[0] == 'Y';
5128 }
5129
5130 int os::stat(const char *path, struct stat *sbuf) {
5131 char pathbuf[MAX_PATH];
5132 if (strlen(path) > MAX_PATH - 1) {
5133 errno = ENAMETOOLONG;
5134 return -1;
5135 }
5136 os::native_path(strcpy(pathbuf, path));
5137 return ::stat(pathbuf, sbuf);
5138 }
5139
5140 // Is a (classpath) directory empty?
5141 bool os::dir_is_empty(const char* path) {
5142 DIR *dir = NULL;
5143 struct dirent *ptr;
5144
5145 dir = opendir(path);
5146 if (dir == NULL) return true;
5147
5148 // Scan the directory
5149 bool result = true;
5150 char buf[sizeof(struct dirent) + MAX_PATH];
5151 while (result && (ptr = ::readdir(dir)) != NULL) {
5152 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5153 result = false;
5154 }
5155 }
5156 closedir(dir);
5157 return result;
5158 }
5159
5160 // This code originates from JDK's sysOpen and open64_w
5161 // from src/solaris/hpi/src/system_md.c
5162
5163 int os::open(const char *path, int oflag, int mode) {
5164 if (strlen(path) > MAX_PATH - 1) {
5165 errno = ENAMETOOLONG;
5166 return -1;
5167 }
5168
5169 // All file descriptors that are opened in the Java process and not
5170 // specifically destined for a subprocess should have the close-on-exec
5171 // flag set. If we don't set it, then careless 3rd party native code
5172 // might fork and exec without closing all appropriate file descriptors
5173 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5174 // turn might:
5175 //
5176 // - cause end-of-file to fail to be detected on some file
5177 // descriptors, resulting in mysterious hangs, or
5178 //
5179 // - might cause an fopen in the subprocess to fail on a system
5180 // suffering from bug 1085341.
5181 //
5182 // (Yes, the default setting of the close-on-exec flag is a Unix
5183 // design flaw)
5184 //
5185 // See:
5186 // 1085341: 32-bit stdio routines should support file descriptors >255
5187 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5188 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5189 //
5190 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5191 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5192 // because it saves a system call and removes a small window where the flag
5193 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5194 // and we fall back to using FD_CLOEXEC (see below).
5195 #ifdef O_CLOEXEC
5196 oflag |= O_CLOEXEC;
5197 #endif
5198
5199 int fd = ::open64(path, oflag, mode);
5200 if (fd == -1) return -1;
5201
5202 //If the open succeeded, the file might still be a directory
5203 {
5204 struct stat64 buf64;
5205 int ret = ::fstat64(fd, &buf64);
5206 int st_mode = buf64.st_mode;
5207
5208 if (ret != -1) {
5209 if ((st_mode & S_IFMT) == S_IFDIR) {
5210 errno = EISDIR;
5211 ::close(fd);
5212 return -1;
5213 }
5214 } else {
5215 ::close(fd);
5216 return -1;
5217 }
5218 }
5219
5220 #ifdef FD_CLOEXEC
5221 // Validate that the use of the O_CLOEXEC flag on open above worked.
5222 // With recent kernels, we will perform this check exactly once.
5223 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5224 if (!O_CLOEXEC_is_known_to_work) {
5225 int flags = ::fcntl(fd, F_GETFD);
5226 if (flags != -1) {
5227 if ((flags & FD_CLOEXEC) != 0)
5228 O_CLOEXEC_is_known_to_work = 1;
5229 else
5230 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5231 }
5232 }
5233 #endif
5234
5235 return fd;
5236 }
5237
5238
5239 // create binary file, rewriting existing file if required
5240 int os::create_binary_file(const char* path, bool rewrite_existing) {
5241 int oflags = O_WRONLY | O_CREAT;
5242 if (!rewrite_existing) {
5243 oflags |= O_EXCL;
5244 }
5245 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5246 }
5247
5248 // return current position of file pointer
5249 jlong os::current_file_offset(int fd) {
5250 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5251 }
5252
5253 // move file pointer to the specified offset
5254 jlong os::seek_to_file_offset(int fd, jlong offset) {
5255 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5256 }
5257
5258 // This code originates from JDK's sysAvailable
5259 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5260
5261 int os::available(int fd, jlong *bytes) {
5262 jlong cur, end;
5263 int mode;
5264 struct stat64 buf64;
5265
5266 if (::fstat64(fd, &buf64) >= 0) {
5267 mode = buf64.st_mode;
5268 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5269 int n;
5270 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5271 *bytes = n;
5272 return 1;
5273 }
5274 }
5275 }
5276 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5277 return 0;
5278 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5279 return 0;
5280 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5281 return 0;
5282 }
5283 *bytes = end - cur;
5284 return 1;
5285 }
5286
5287 // Map a block of memory.
5288 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5289 char *addr, size_t bytes, bool read_only,
5290 bool allow_exec) {
5291 int prot;
5292 int flags = MAP_PRIVATE;
5293
5294 if (read_only) {
5295 prot = PROT_READ;
5296 } else {
5297 prot = PROT_READ | PROT_WRITE;
5298 }
5299
5300 if (allow_exec) {
5301 prot |= PROT_EXEC;
5302 }
5303
5304 if (addr != NULL) {
5305 flags |= MAP_FIXED;
5306 }
5307
5308 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5309 fd, file_offset);
5310 if (mapped_address == MAP_FAILED) {
5311 return NULL;
5312 }
5313 return mapped_address;
5314 }
5315
5316
5317 // Remap a block of memory.
5318 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5319 char *addr, size_t bytes, bool read_only,
5320 bool allow_exec) {
5321 // same as map_memory() on this OS
5322 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5323 allow_exec);
5324 }
5325
5326
5327 // Unmap a block of memory.
5328 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5329 return munmap(addr, bytes) == 0;
5330 }
5331
5332 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5333
5334 static clockid_t thread_cpu_clockid(Thread* thread) {
5335 pthread_t tid = thread->osthread()->pthread_id();
5336 clockid_t clockid;
5337
5338 // Get thread clockid
5339 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5340 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5341 return clockid;
5342 }
5343
5344 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5345 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5346 // of a thread.
5347 //
5348 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5349 // the fast estimate available on the platform.
5350
5351 jlong os::current_thread_cpu_time() {
5352 if (os::Linux::supports_fast_thread_cpu_time()) {
5353 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5354 } else {
5355 // return user + sys since the cost is the same
5356 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5357 }
5358 }
5359
5360 jlong os::thread_cpu_time(Thread* thread) {
5361 // consistent with what current_thread_cpu_time() returns
5362 if (os::Linux::supports_fast_thread_cpu_time()) {
5363 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5364 } else {
5365 return slow_thread_cpu_time(thread, true /* user + sys */);
5366 }
5367 }
5368
5369 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5370 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5371 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5372 } else {
5373 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5374 }
5375 }
5376
5377 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5378 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5379 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5380 } else {
5381 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5382 }
5383 }
5384
5385 // -1 on error.
5386 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5387 pid_t tid = thread->osthread()->thread_id();
5388 char *s;
5389 char stat[2048];
5390 int statlen;
5391 char proc_name[64];
5392 int count;
5393 long sys_time, user_time;
5394 char cdummy;
5395 int idummy;
5396 long ldummy;
5397 FILE *fp;
5398
5399 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5400 fp = fopen(proc_name, "r");
5401 if (fp == NULL) return -1;
5402 statlen = fread(stat, 1, 2047, fp);
5403 stat[statlen] = '\0';
5404 fclose(fp);
5405
5406 // Skip pid and the command string. Note that we could be dealing with
5407 // weird command names, e.g. user could decide to rename java launcher
5408 // to "java 1.4.2 :)", then the stat file would look like
5409 // 1234 (java 1.4.2 :)) R ... ...
5410 // We don't really need to know the command string, just find the last
5411 // occurrence of ")" and then start parsing from there. See bug 4726580.
5412 s = strrchr(stat, ')');
5413 if (s == NULL) return -1;
5414
5415 // Skip blank chars
5416 do { s++; } while (s && isspace(*s));
5417
5418 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5419 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5420 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5421 &user_time, &sys_time);
5422 if (count != 13) return -1;
5423 if (user_sys_cpu_time) {
5424 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5425 } else {
5426 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5427 }
5428 }
5429
5430 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5431 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5432 info_ptr->may_skip_backward = false; // elapsed time not wall time
5433 info_ptr->may_skip_forward = false; // elapsed time not wall time
5434 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5435 }
5436
5437 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5438 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5439 info_ptr->may_skip_backward = false; // elapsed time not wall time
5440 info_ptr->may_skip_forward = false; // elapsed time not wall time
5441 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5442 }
5443
5444 bool os::is_thread_cpu_time_supported() {
5445 return true;
5446 }
5447
5448 // System loadavg support. Returns -1 if load average cannot be obtained.
5449 // Linux doesn't yet have a (official) notion of processor sets,
5450 // so just return the system wide load average.
5451 int os::loadavg(double loadavg[], int nelem) {
5452 return ::getloadavg(loadavg, nelem);
5453 }
5454
5455 void os::pause() {
5456 char filename[MAX_PATH];
5457 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5458 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5459 } else {
5460 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5461 }
5462
5463 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5464 if (fd != -1) {
5465 struct stat buf;
5466 ::close(fd);
5467 while (::stat(filename, &buf) == 0) {
5468 (void)::poll(NULL, 0, 100);
5469 }
5470 } else {
5471 jio_fprintf(stderr,
5472 "Could not open pause file '%s', continuing immediately.\n", filename);
5473 }
5474 }
5475
5476 extern char** environ;
5477
5478 // Run the specified command in a separate process. Return its exit value,
5479 // or -1 on failure (e.g. can't fork a new process).
5480 // Unlike system(), this function can be called from signal handler. It
5481 // doesn't block SIGINT et al.
5482 int os::fork_and_exec(char* cmd) {
5483 const char * argv[4] = {"sh", "-c", cmd, NULL};
5484
5485 pid_t pid = fork();
5486
5487 if (pid < 0) {
5488 // fork failed
5489 return -1;
5490
5491 } else if (pid == 0) {
5492 // child process
5493
5494 execve("/bin/sh", (char* const*)argv, environ);
5495
5496 // execve failed
5497 _exit(-1);
5498
5499 } else {
5500 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5501 // care about the actual exit code, for now.
5502
5503 int status;
5504
5505 // Wait for the child process to exit. This returns immediately if
5506 // the child has already exited. */
5507 while (waitpid(pid, &status, 0) < 0) {
5508 switch (errno) {
5509 case ECHILD: return 0;
5510 case EINTR: break;
5511 default: return -1;
5512 }
5513 }
5514
5515 if (WIFEXITED(status)) {
5516 // The child exited normally; get its exit code.
5517 return WEXITSTATUS(status);
5518 } else if (WIFSIGNALED(status)) {
5519 // The child exited because of a signal
5520 // The best value to return is 0x80 + signal number,
5521 // because that is what all Unix shells do, and because
5522 // it allows callers to distinguish between process exit and
5523 // process death by signal.
5524 return 0x80 + WTERMSIG(status);
5525 } else {
5526 // Unknown exit code; pass it through
5527 return status;
5528 }
5529 }
5530 }
5531
5532 // is_headless_jre()
5533 //
5534 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5535 // in order to report if we are running in a headless jre
5536 //
5537 // Since JDK8 xawt/libmawt.so was moved into the same directory
5538 // as libawt.so, and renamed libawt_xawt.so
5539 //
5540 bool os::is_headless_jre() {
5541 struct stat statbuf;
5542 char buf[MAXPATHLEN];
5543 char libmawtpath[MAXPATHLEN];
5544 const char *xawtstr = "/xawt/libmawt.so";
5545 const char *new_xawtstr = "/libawt_xawt.so";
5546 char *p;
5547
5548 // Get path to libjvm.so
5549 os::jvm_path(buf, sizeof(buf));
5550
5551 // Get rid of libjvm.so
5552 p = strrchr(buf, '/');
5553 if (p == NULL) {
5554 return false;
5555 } else {
5556 *p = '\0';
5557 }
5558
5559 // Get rid of client or server
5560 p = strrchr(buf, '/');
5561 if (p == NULL) {
5562 return false;
5563 } else {
5564 *p = '\0';
5565 }
5566
5567 // check xawt/libmawt.so
5568 strcpy(libmawtpath, buf);
5569 strcat(libmawtpath, xawtstr);
5570 if (::stat(libmawtpath, &statbuf) == 0) return false;
5571
5572 // check libawt_xawt.so
5573 strcpy(libmawtpath, buf);
5574 strcat(libmawtpath, new_xawtstr);
5575 if (::stat(libmawtpath, &statbuf) == 0) return false;
5576
5577 return true;
5578 }
5579
5580 // Get the default path to the core file
5581 // Returns the length of the string
5582 int os::get_core_path(char* buffer, size_t bufferSize) {
5583 /*
5584 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5585 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5586 */
5587 const int core_pattern_len = 129;
5588 char core_pattern[core_pattern_len] = {0};
5589
5590 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5591 if (core_pattern_file == -1) {
5592 return -1;
5593 }
5594
5595 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5596 ::close(core_pattern_file);
5597 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5598 return -1;
5599 }
5600 if (core_pattern[ret-1] == '\n') {
5601 core_pattern[ret-1] = '\0';
5602 } else {
5603 core_pattern[ret] = '\0';
5604 }
5605
5606 char *pid_pos = strstr(core_pattern, "%p");
5607 int written;
5608
5609 if (core_pattern[0] == '/') {
5610 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5611 } else {
5612 char cwd[PATH_MAX];
5613
5614 const char* p = get_current_directory(cwd, PATH_MAX);
5615 if (p == NULL) {
5616 return -1;
5617 }
5618
5619 if (core_pattern[0] == '|') {
5620 written = jio_snprintf(buffer, bufferSize,
5621 "\"%s\" (or dumping to %s/core.%d)",
5622 &core_pattern[1], p, current_process_id());
5623 } else {
5624 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5625 }
5626 }
5627
5628 if (written < 0) {
5629 return -1;
5630 }
5631
5632 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5633 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5634
5635 if (core_uses_pid_file != -1) {
5636 char core_uses_pid = 0;
5637 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5638 ::close(core_uses_pid_file);
5639
5640 if (core_uses_pid == '1') {
5641 jio_snprintf(buffer + written, bufferSize - written,
5642 ".%d", current_process_id());
5643 }
5644 }
5645 }
5646
5647 return strlen(buffer);
5648 }
5649
5650 bool os::start_debugging(char *buf, int buflen) {
5651 int len = (int)strlen(buf);
5652 char *p = &buf[len];
5653
5654 jio_snprintf(p, buflen-len,
5655 "\n\n"
5656 "Do you want to debug the problem?\n\n"
5657 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
5658 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
5659 "Otherwise, press RETURN to abort...",
5660 os::current_process_id(), os::current_process_id(),
5661 os::current_thread_id(), os::current_thread_id());
5662
5663 bool yes = os::message_box("Unexpected Error", buf);
5664
5665 if (yes) {
5666 // yes, user asked VM to launch debugger
5667 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
5668 os::current_process_id(), os::current_process_id());
5669
5670 os::fork_and_exec(buf);
5671 yes = false;
5672 }
5673 return yes;
5674 }
5675
5676
5677 // Java/Compiler thread:
5678 //
5679 // Low memory addresses
5680 // P0 +------------------------+
5681 // | |\ Java thread created by VM does not have glibc
5682 // | glibc guard page | - guard page, attached Java thread usually has
5683 // | |/ 1 glibc guard page.
5684 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5685 // | |\
5686 // | HotSpot Guard Pages | - red, yellow and reserved pages
5687 // | |/
5688 // +------------------------+ JavaThread::stack_reserved_zone_base()
5689 // | |\
5690 // | Normal Stack | -
5691 // | |/
5692 // P2 +------------------------+ Thread::stack_base()
5693 //
5694 // Non-Java thread:
5695 //
5696 // Low memory addresses
5697 // P0 +------------------------+
5698 // | |\
5699 // | glibc guard page | - usually 1 page
5700 // | |/
5701 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
5702 // | |\
5703 // | Normal Stack | -
5704 // | |/
5705 // P2 +------------------------+ Thread::stack_base()
5706 //
5707 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
5708 // returned from pthread_attr_getstack().
5709 // ** Due to NPTL implementation error, linux takes the glibc guard page out
5710 // of the stack size given in pthread_attr. We work around this for
5711 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
5712 //
5713 #ifndef ZERO
5714 static void current_stack_region(address * bottom, size_t * size) {
5715 if (os::Linux::is_initial_thread()) {
5716 // initial thread needs special handling because pthread_getattr_np()
5717 // may return bogus value.
5718 *bottom = os::Linux::initial_thread_stack_bottom();
5719 *size = os::Linux::initial_thread_stack_size();
5720 } else {
5721 pthread_attr_t attr;
5722
5723 int rslt = pthread_getattr_np(pthread_self(), &attr);
5724
5725 // JVM needs to know exact stack location, abort if it fails
5726 if (rslt != 0) {
5727 if (rslt == ENOMEM) {
5728 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
5729 } else {
5730 fatal("pthread_getattr_np failed with error = %d", rslt);
5731 }
5732 }
5733
5734 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
5735 fatal("Cannot locate current stack attributes!");
5736 }
5737
5738 // Work around NPTL stack guard error.
5739 size_t guard_size = 0;
5740 rslt = pthread_attr_getguardsize(&attr, &guard_size);
5741 if (rslt != 0) {
5742 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
5743 }
5744 *bottom += guard_size;
5745 *size -= guard_size;
5746
5747 pthread_attr_destroy(&attr);
5748
5749 }
5750 assert(os::current_stack_pointer() >= *bottom &&
5751 os::current_stack_pointer() < *bottom + *size, "just checking");
5752 }
5753
5754 address os::current_stack_base() {
5755 address bottom;
5756 size_t size;
5757 current_stack_region(&bottom, &size);
5758 return (bottom + size);
5759 }
5760
5761 size_t os::current_stack_size() {
5762 // This stack size includes the usable stack and HotSpot guard pages
5763 // (for the threads that have Hotspot guard pages).
5764 address bottom;
5765 size_t size;
5766 current_stack_region(&bottom, &size);
5767 return size;
5768 }
5769 #endif
5770
5771 static inline struct timespec get_mtime(const char* filename) {
5772 struct stat st;
5773 int ret = os::stat(filename, &st);
5774 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
5775 return st.st_mtim;
5776 }
5777
5778 int os::compare_file_modified_times(const char* file1, const char* file2) {
5779 struct timespec filetime1 = get_mtime(file1);
5780 struct timespec filetime2 = get_mtime(file2);
5781 int diff = filetime1.tv_sec - filetime2.tv_sec;
5782 if (diff == 0) {
5783 return filetime1.tv_nsec - filetime2.tv_nsec;
5784 }
5785 return diff;
5786 }
5787
5788 /////////////// Unit tests ///////////////
5789
5790 #ifndef PRODUCT
5791
5792 #define test_log(...) \
5793 do { \
5794 if (VerboseInternalVMTests) { \
5795 tty->print_cr(__VA_ARGS__); \
5796 tty->flush(); \
5797 } \
5798 } while (false)
5799
5800 class TestReserveMemorySpecial : AllStatic {
5801 public:
5802 static void small_page_write(void* addr, size_t size) {
5803 size_t page_size = os::vm_page_size();
5804
5805 char* end = (char*)addr + size;
5806 for (char* p = (char*)addr; p < end; p += page_size) {
5807 *p = 1;
5808 }
5809 }
5810
5811 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
5812 if (!UseHugeTLBFS) {
5813 return;
5814 }
5815
5816 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
5817
5818 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
5819
5820 if (addr != NULL) {
5821 small_page_write(addr, size);
5822
5823 os::Linux::release_memory_special_huge_tlbfs(addr, size);
5824 }
5825 }
5826
5827 static void test_reserve_memory_special_huge_tlbfs_only() {
5828 if (!UseHugeTLBFS) {
5829 return;
5830 }
5831
5832 size_t lp = os::large_page_size();
5833
5834 for (size_t size = lp; size <= lp * 10; size += lp) {
5835 test_reserve_memory_special_huge_tlbfs_only(size);
5836 }
5837 }
5838
5839 static void test_reserve_memory_special_huge_tlbfs_mixed() {
5840 size_t lp = os::large_page_size();
5841 size_t ag = os::vm_allocation_granularity();
5842
5843 // sizes to test
5844 const size_t sizes[] = {
5845 lp, lp + ag, lp + lp / 2, lp * 2,
5846 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
5847 lp * 10, lp * 10 + lp / 2
5848 };
5849 const int num_sizes = sizeof(sizes) / sizeof(size_t);
5850
5851 // For each size/alignment combination, we test three scenarios:
5852 // 1) with req_addr == NULL
5853 // 2) with a non-null req_addr at which we expect to successfully allocate
5854 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
5855 // expect the allocation to either fail or to ignore req_addr
5856
5857 // Pre-allocate two areas; they shall be as large as the largest allocation
5858 // and aligned to the largest alignment we will be testing.
5859 const size_t mapping_size = sizes[num_sizes - 1] * 2;
5860 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
5861 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
5862 -1, 0);
5863 assert(mapping1 != MAP_FAILED, "should work");
5864
5865 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
5866 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
5867 -1, 0);
5868 assert(mapping2 != MAP_FAILED, "should work");
5869
5870 // Unmap the first mapping, but leave the second mapping intact: the first
5871 // mapping will serve as a value for a "good" req_addr (case 2). The second
5872 // mapping, still intact, as "bad" req_addr (case 3).
5873 ::munmap(mapping1, mapping_size);
5874
5875 // Case 1
5876 test_log("%s, req_addr NULL:", __FUNCTION__);
5877 test_log("size align result");
5878
5879 for (int i = 0; i < num_sizes; i++) {
5880 const size_t size = sizes[i];
5881 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5882 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
5883 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
5884 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
5885 if (p != NULL) {
5886 assert(is_ptr_aligned(p, alignment), "must be");
5887 small_page_write(p, size);
5888 os::Linux::release_memory_special_huge_tlbfs(p, size);
5889 }
5890 }
5891 }
5892
5893 // Case 2
5894 test_log("%s, req_addr non-NULL:", __FUNCTION__);
5895 test_log("size align req_addr result");
5896
5897 for (int i = 0; i < num_sizes; i++) {
5898 const size_t size = sizes[i];
5899 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5900 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
5901 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
5902 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
5903 size, alignment, p2i(req_addr), p2i(p),
5904 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
5905 if (p != NULL) {
5906 assert(p == req_addr, "must be");
5907 small_page_write(p, size);
5908 os::Linux::release_memory_special_huge_tlbfs(p, size);
5909 }
5910 }
5911 }
5912
5913 // Case 3
5914 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
5915 test_log("size align req_addr result");
5916
5917 for (int i = 0; i < num_sizes; i++) {
5918 const size_t size = sizes[i];
5919 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5920 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
5921 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
5922 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
5923 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
5924 // as the area around req_addr contains already existing mappings, the API should always
5925 // return NULL (as per contract, it cannot return another address)
5926 assert(p == NULL, "must be");
5927 }
5928 }
5929
5930 ::munmap(mapping2, mapping_size);
5931
5932 }
5933
5934 static void test_reserve_memory_special_huge_tlbfs() {
5935 if (!UseHugeTLBFS) {
5936 return;
5937 }
5938
5939 test_reserve_memory_special_huge_tlbfs_only();
5940 test_reserve_memory_special_huge_tlbfs_mixed();
5941 }
5942
5943 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
5944 if (!UseSHM) {
5945 return;
5946 }
5947
5948 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
5949
5950 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
5951
5952 if (addr != NULL) {
5953 assert(is_ptr_aligned(addr, alignment), "Check");
5954 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
5955
5956 small_page_write(addr, size);
5957
5958 os::Linux::release_memory_special_shm(addr, size);
5959 }
5960 }
5961
5962 static void test_reserve_memory_special_shm() {
5963 size_t lp = os::large_page_size();
5964 size_t ag = os::vm_allocation_granularity();
5965
5966 for (size_t size = ag; size < lp * 3; size += ag) {
5967 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
5968 test_reserve_memory_special_shm(size, alignment);
5969 }
5970 }
5971 }
5972
5973 static void test() {
5974 test_reserve_memory_special_huge_tlbfs();
5975 test_reserve_memory_special_shm();
5976 }
5977 };
5978
5979 void TestReserveMemorySpecial_test() {
5980 TestReserveMemorySpecial::test();
5981 }
5982
5983 #endif