1 /*
2 * Copyright (c) 1999, 2016, 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 <sys/ipc.h>
102 # include <sys/shm.h>
103 # include <link.h>
104 # include <stdint.h>
105 # include <inttypes.h>
106 # include <sys/ioctl.h>
107
108 #ifndef _GNU_SOURCE
109 #define _GNU_SOURCE
110 #include <sched.h>
111 #undef _GNU_SOURCE
112 #else
113 #include <sched.h>
114 #endif
115
116 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
117 // getrusage() is prepared to handle the associated failure.
118 #ifndef RUSAGE_THREAD
119 #define RUSAGE_THREAD (1) /* only the calling thread */
120 #endif
121
122 #define MAX_PATH (2 * K)
123
124 #define MAX_SECS 100000000
125
126 // for timer info max values which include all bits
127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
128
129 #define LARGEPAGES_BIT (1 << 6)
130 ////////////////////////////////////////////////////////////////////////////////
131 // global variables
132 julong os::Linux::_physical_memory = 0;
133
134 address os::Linux::_initial_thread_stack_bottom = NULL;
135 uintptr_t os::Linux::_initial_thread_stack_size = 0;
136
137 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
138 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
139 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
140 Mutex* os::Linux::_createThread_lock = NULL;
141 pthread_t os::Linux::_main_thread;
142 int os::Linux::_page_size = -1;
143 bool os::Linux::_supports_fast_thread_cpu_time = false;
144 uint32_t os::Linux::_os_version = 0;
145 const char * os::Linux::_glibc_version = "unknown";
146 const char * os::Linux::_libpthread_version = "unknown";
147 pthread_condattr_t os::Linux::_condattr[1];
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 // Declarations
164 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
165
166 // utility functions
167
168 static int SR_initialize();
169
170 julong os::available_memory() {
171 return Linux::available_memory();
172 }
173
174 julong os::Linux::available_memory() {
175 // values in struct sysinfo are "unsigned long"
176 struct sysinfo si;
177 sysinfo(&si);
178
179 return (julong)si.freeram * si.mem_unit;
180 }
181
182 julong os::physical_memory() {
183 return Linux::physical_memory();
184 }
185
186 // Return true if user is running as root.
187
188 bool os::have_special_privileges() {
189 static bool init = false;
190 static bool privileges = false;
191 if (!init) {
192 privileges = (getuid() != geteuid()) || (getgid() != getegid());
193 init = true;
194 }
195 return privileges;
196 }
197
198
199 #ifndef SYS_gettid
200 // i386: 224, ia64: 1105, amd64: 186, sparc 143
201 #ifdef __ia64__
202 #define SYS_gettid 1105
203 #else
204 #ifdef __i386__
205 #define SYS_gettid 224
206 #else
207 #ifdef __amd64__
208 #define SYS_gettid 186
209 #else
210 #ifdef __sparc__
211 #define SYS_gettid 143
212 #else
213 #error define gettid for the arch
214 #endif
215 #endif
216 #endif
217 #endif
218 #endif
219
220
221 // pid_t gettid()
222 //
223 // Returns the kernel thread id of the currently running thread. Kernel
224 // thread id is used to access /proc.
225 pid_t os::Linux::gettid() {
226 int rslt = syscall(SYS_gettid);
227 assert(rslt != -1, "must be."); // old linuxthreads implementation?
228 return (pid_t)rslt;
229 }
230
231 // Most versions of linux have a bug where the number of processors are
232 // determined by looking at the /proc file system. In a chroot environment,
233 // the system call returns 1. This causes the VM to act as if it is
234 // a single processor and elide locking (see is_MP() call).
235 static bool unsafe_chroot_detected = false;
236 static const char *unstable_chroot_error = "/proc file system not found.\n"
237 "Java may be unstable running multithreaded in a chroot "
238 "environment on Linux when /proc filesystem is not mounted.";
239
240 void os::Linux::initialize_system_info() {
241 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
242 if (processor_count() == 1) {
243 pid_t pid = os::Linux::gettid();
244 char fname[32];
245 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
246 FILE *fp = fopen(fname, "r");
247 if (fp == NULL) {
248 unsafe_chroot_detected = true;
249 } else {
250 fclose(fp);
251 }
252 }
253 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
254 assert(processor_count() > 0, "linux error");
255 }
256
257 void os::init_system_properties_values() {
258 // The next steps are taken in the product version:
259 //
260 // Obtain the JAVA_HOME value from the location of libjvm.so.
261 // This library should be located at:
262 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
263 //
264 // If "/jre/lib/" appears at the right place in the path, then we
265 // assume libjvm.so is installed in a JDK and we use this path.
266 //
267 // Otherwise exit with message: "Could not create the Java virtual machine."
268 //
269 // The following extra steps are taken in the debugging version:
270 //
271 // If "/jre/lib/" does NOT appear at the right place in the path
272 // instead of exit check for $JAVA_HOME environment variable.
273 //
274 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
275 // then we append a fake suffix "hotspot/libjvm.so" to this path so
276 // it looks like libjvm.so is installed there
277 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
278 //
279 // Otherwise exit.
280 //
281 // Important note: if the location of libjvm.so changes this
282 // code needs to be changed accordingly.
283
284 // See ld(1):
285 // The linker uses the following search paths to locate required
286 // shared libraries:
287 // 1: ...
288 // ...
289 // 7: The default directories, normally /lib and /usr/lib.
290 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
291 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
292 #else
293 #define DEFAULT_LIBPATH "/lib:/usr/lib"
294 #endif
295
296 // Base path of extensions installed on the system.
297 #define SYS_EXT_DIR "/usr/java/packages"
298 #define EXTENSIONS_DIR "/lib/ext"
299
300 // Buffer that fits several sprintfs.
301 // Note that the space for the colon and the trailing null are provided
302 // by the nulls included by the sizeof operator.
303 const size_t bufsize =
304 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
305 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
306 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
307
308 // sysclasspath, java_home, dll_dir
309 {
310 char *pslash;
311 os::jvm_path(buf, bufsize);
312
313 // Found the full path to libjvm.so.
314 // Now cut the path to <java_home>/jre if we can.
315 pslash = strrchr(buf, '/');
316 if (pslash != NULL) {
317 *pslash = '\0'; // Get rid of /libjvm.so.
318 }
319 pslash = strrchr(buf, '/');
320 if (pslash != NULL) {
321 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
322 }
323 Arguments::set_dll_dir(buf);
324
325 if (pslash != NULL) {
326 pslash = strrchr(buf, '/');
327 if (pslash != NULL) {
328 *pslash = '\0'; // Get rid of /lib.
329 }
330 }
331 Arguments::set_java_home(buf);
332 set_boot_path('/', ':');
333 }
334
335 // Where to look for native libraries.
336 //
337 // Note: Due to a legacy implementation, most of the library path
338 // is set in the launcher. This was to accomodate linking restrictions
339 // on legacy Linux implementations (which are no longer supported).
340 // Eventually, all the library path setting will be done here.
341 //
342 // However, to prevent the proliferation of improperly built native
343 // libraries, the new path component /usr/java/packages is added here.
344 // Eventually, all the library path setting will be done here.
345 {
346 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
347 // should always exist (until the legacy problem cited above is
348 // addressed).
349 const char *v = ::getenv("LD_LIBRARY_PATH");
350 const char *v_colon = ":";
351 if (v == NULL) { v = ""; v_colon = ""; }
352 // That's +1 for the colon and +1 for the trailing '\0'.
353 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
354 strlen(v) + 1 +
355 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
356 mtInternal);
357 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
358 Arguments::set_library_path(ld_library_path);
359 FREE_C_HEAP_ARRAY(char, ld_library_path);
360 }
361
362 // Extensions directories.
363 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
364 Arguments::set_ext_dirs(buf);
365
366 FREE_C_HEAP_ARRAY(char, buf);
367
368 #undef DEFAULT_LIBPATH
369 #undef SYS_EXT_DIR
370 #undef EXTENSIONS_DIR
371 }
372
373 ////////////////////////////////////////////////////////////////////////////////
374 // breakpoint support
375
376 void os::breakpoint() {
377 BREAKPOINT;
378 }
379
380 extern "C" void breakpoint() {
381 // use debugger to set breakpoint here
382 }
383
384 ////////////////////////////////////////////////////////////////////////////////
385 // signal support
386
387 debug_only(static bool signal_sets_initialized = false);
388 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
389
390 bool os::Linux::is_sig_ignored(int sig) {
391 struct sigaction oact;
392 sigaction(sig, (struct sigaction*)NULL, &oact);
393 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
394 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
395 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
396 return true;
397 } else {
398 return false;
399 }
400 }
401
402 void os::Linux::signal_sets_init() {
403 // Should also have an assertion stating we are still single-threaded.
404 assert(!signal_sets_initialized, "Already initialized");
405 // Fill in signals that are necessarily unblocked for all threads in
406 // the VM. Currently, we unblock the following signals:
407 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
408 // by -Xrs (=ReduceSignalUsage));
409 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
410 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
411 // the dispositions or masks wrt these signals.
412 // Programs embedding the VM that want to use the above signals for their
413 // own purposes must, at this time, use the "-Xrs" option to prevent
414 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
415 // (See bug 4345157, and other related bugs).
416 // In reality, though, unblocking these signals is really a nop, since
417 // these signals are not blocked by default.
418 sigemptyset(&unblocked_sigs);
419 sigemptyset(&allowdebug_blocked_sigs);
420 sigaddset(&unblocked_sigs, SIGILL);
421 sigaddset(&unblocked_sigs, SIGSEGV);
422 sigaddset(&unblocked_sigs, SIGBUS);
423 sigaddset(&unblocked_sigs, SIGFPE);
424 #if defined(PPC64)
425 sigaddset(&unblocked_sigs, SIGTRAP);
426 #endif
427 sigaddset(&unblocked_sigs, SR_signum);
428
429 if (!ReduceSignalUsage) {
430 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
431 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
432 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
433 }
434 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
435 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
436 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
437 }
438 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
439 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
441 }
442 }
443 // Fill in signals that are blocked by all but the VM thread.
444 sigemptyset(&vm_sigs);
445 if (!ReduceSignalUsage) {
446 sigaddset(&vm_sigs, BREAK_SIGNAL);
447 }
448 debug_only(signal_sets_initialized = true);
449
450 }
451
452 // These are signals that are unblocked while a thread is running Java.
453 // (For some reason, they get blocked by default.)
454 sigset_t* os::Linux::unblocked_signals() {
455 assert(signal_sets_initialized, "Not initialized");
456 return &unblocked_sigs;
457 }
458
459 // These are the signals that are blocked while a (non-VM) thread is
460 // running Java. Only the VM thread handles these signals.
461 sigset_t* os::Linux::vm_signals() {
462 assert(signal_sets_initialized, "Not initialized");
463 return &vm_sigs;
464 }
465
466 // These are signals that are blocked during cond_wait to allow debugger in
467 sigset_t* os::Linux::allowdebug_blocked_signals() {
468 assert(signal_sets_initialized, "Not initialized");
469 return &allowdebug_blocked_sigs;
470 }
471
472 void os::Linux::hotspot_sigmask(Thread* thread) {
473
474 //Save caller's signal mask before setting VM signal mask
475 sigset_t caller_sigmask;
476 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
477
478 OSThread* osthread = thread->osthread();
479 osthread->set_caller_sigmask(caller_sigmask);
480
481 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
482
483 if (!ReduceSignalUsage) {
484 if (thread->is_VM_thread()) {
485 // Only the VM thread handles BREAK_SIGNAL ...
486 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
487 } else {
488 // ... all other threads block BREAK_SIGNAL
489 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
490 }
491 }
492 }
493
494 //////////////////////////////////////////////////////////////////////////////
495 // detecting pthread library
496
497 void os::Linux::libpthread_init() {
498 // Save glibc and pthread version strings.
499 #if !defined(_CS_GNU_LIBC_VERSION) || \
500 !defined(_CS_GNU_LIBPTHREAD_VERSION)
501 #error "glibc too old (< 2.3.2)"
502 #endif
503
504 size_t n;
505
506 n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
507 if (n > 0) {
508 char* str = (char *)malloc(n, mtInternal);
509 confstr(_CS_GNU_LIBC_VERSION, str, n);
510 os::Linux::set_glibc_version(str);
511 }
512
513 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
514 if (n > 0) {
515 char* str = (char *)malloc(n, mtInternal);
516 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
517 os::Linux::set_libpthread_version(str);
518 }
519 }
520
521 /////////////////////////////////////////////////////////////////////////////
522 // thread stack expansion
523
524 // os::Linux::manually_expand_stack() takes care of expanding the thread
525 // stack. Note that this is normally not needed: pthread stacks allocate
526 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
527 // committed. Therefore it is not necessary to expand the stack manually.
528 //
529 // Manually expanding the stack was historically needed on LinuxThreads
530 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
531 // it is kept to deal with very rare corner cases:
532 //
533 // For one, user may run the VM on an own implementation of threads
534 // whose stacks are - like the old LinuxThreads - implemented using
535 // mmap(MAP_GROWSDOWN).
536 //
537 // Also, this coding may be needed if the VM is running on the primordial
538 // thread. Normally we avoid running on the primordial thread; however,
539 // user may still invoke the VM on the primordial thread.
540 //
541 // The following historical comment describes the details about running
542 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
543
544
545 // Force Linux kernel to expand current thread stack. If "bottom" is close
546 // to the stack guard, caller should block all signals.
547 //
548 // MAP_GROWSDOWN:
549 // A special mmap() flag that is used to implement thread stacks. It tells
550 // kernel that the memory region should extend downwards when needed. This
551 // allows early versions of LinuxThreads to only mmap the first few pages
552 // when creating a new thread. Linux kernel will automatically expand thread
553 // stack as needed (on page faults).
554 //
555 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
556 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
557 // region, it's hard to tell if the fault is due to a legitimate stack
558 // access or because of reading/writing non-exist memory (e.g. buffer
559 // overrun). As a rule, if the fault happens below current stack pointer,
560 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
561 // application (see Linux kernel fault.c).
562 //
563 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
564 // stack overflow detection.
565 //
566 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
567 // not use MAP_GROWSDOWN.
568 //
569 // To get around the problem and allow stack banging on Linux, we need to
570 // manually expand thread stack after receiving the SIGSEGV.
571 //
572 // There are two ways to expand thread stack to address "bottom", we used
573 // both of them in JVM before 1.5:
574 // 1. adjust stack pointer first so that it is below "bottom", and then
575 // touch "bottom"
576 // 2. mmap() the page in question
577 //
578 // Now alternate signal stack is gone, it's harder to use 2. For instance,
579 // if current sp is already near the lower end of page 101, and we need to
580 // call mmap() to map page 100, it is possible that part of the mmap() frame
581 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
582 // That will destroy the mmap() frame and cause VM to crash.
583 //
584 // The following code works by adjusting sp first, then accessing the "bottom"
585 // page to force a page fault. Linux kernel will then automatically expand the
586 // stack mapping.
587 //
588 // _expand_stack_to() assumes its frame size is less than page size, which
589 // should always be true if the function is not inlined.
590
591 static void NOINLINE _expand_stack_to(address bottom) {
592 address sp;
593 size_t size;
594 volatile char *p;
595
596 // Adjust bottom to point to the largest address within the same page, it
597 // gives us a one-page buffer if alloca() allocates slightly more memory.
598 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
599 bottom += os::Linux::page_size() - 1;
600
601 // sp might be slightly above current stack pointer; if that's the case, we
602 // will alloca() a little more space than necessary, which is OK. Don't use
603 // os::current_stack_pointer(), as its result can be slightly below current
604 // stack pointer, causing us to not alloca enough to reach "bottom".
605 sp = (address)&sp;
606
607 if (sp > bottom) {
608 size = sp - bottom;
609 p = (volatile char *)alloca(size);
610 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
611 p[0] = '\0';
612 }
613 }
614
615 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
616 assert(t!=NULL, "just checking");
617 assert(t->osthread()->expanding_stack(), "expand should be set");
618 assert(t->stack_base() != NULL, "stack_base was not initialized");
619
620 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
621 sigset_t mask_all, old_sigset;
622 sigfillset(&mask_all);
623 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
624 _expand_stack_to(addr);
625 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
626 return true;
627 }
628 return false;
629 }
630
631 //////////////////////////////////////////////////////////////////////////////
632 // create new thread
633
634 // Thread start routine for all newly created threads
635 static void *thread_native_entry(Thread *thread) {
636 // Try to randomize the cache line index of hot stack frames.
637 // This helps when threads of the same stack traces evict each other's
638 // cache lines. The threads can be either from the same JVM instance, or
639 // from different JVM instances. The benefit is especially true for
640 // processors with hyperthreading technology.
641 static int counter = 0;
642 int pid = os::current_process_id();
643 alloca(((pid ^ counter++) & 7) * 128);
644
645 thread->initialize_thread_current();
646
647 OSThread* osthread = thread->osthread();
648 Monitor* sync = osthread->startThread_lock();
649
650 osthread->set_thread_id(os::current_thread_id());
651
652 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
653 os::current_thread_id(), (uintx) pthread_self());
654
655 if (UseNUMA) {
656 int lgrp_id = os::numa_get_group_id();
657 if (lgrp_id != -1) {
658 thread->set_lgrp_id(lgrp_id);
659 }
660 }
661 // initialize signal mask for this thread
662 os::Linux::hotspot_sigmask(thread);
663
664 // initialize floating point control register
665 os::Linux::init_thread_fpu_state();
666
667 // handshaking with parent thread
668 {
669 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
670
671 // notify parent thread
672 osthread->set_state(INITIALIZED);
673 sync->notify_all();
674
675 // wait until os::start_thread()
676 while (osthread->get_state() == INITIALIZED) {
677 sync->wait(Mutex::_no_safepoint_check_flag);
678 }
679 }
680
681 // call one more level start routine
682 thread->run();
683
684 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
685 os::current_thread_id(), (uintx) pthread_self());
686
687 // If a thread has not deleted itself ("delete this") as part of its
688 // termination sequence, we have to ensure thread-local-storage is
689 // cleared before we actually terminate. No threads should ever be
690 // deleted asynchronously with respect to their termination.
691 if (Thread::current_or_null_safe() != NULL) {
692 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
693 thread->clear_thread_current();
694 }
695
696 return 0;
697 }
698
699 bool os::create_thread(Thread* thread, ThreadType thr_type,
700 size_t req_stack_size) {
701 assert(thread->osthread() == NULL, "caller responsible");
702
703 // Allocate the OSThread object
704 OSThread* osthread = new OSThread(NULL, NULL);
705 if (osthread == NULL) {
706 return false;
707 }
708
709 // set the correct thread state
710 osthread->set_thread_type(thr_type);
711
712 // Initial state is ALLOCATED but not INITIALIZED
713 osthread->set_state(ALLOCATED);
714
715 thread->set_osthread(osthread);
716
717 // init thread attributes
718 pthread_attr_t attr;
719 pthread_attr_init(&attr);
720 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
721
722 // Calculate stack size if it's not specified by caller.
723 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
724 // In the Linux NPTL pthread implementation the guard size mechanism
725 // is not implemented properly. The posix standard requires adding
726 // the size of the guard pages to the stack size, instead Linux
727 // takes the space out of 'stacksize'. Thus we adapt the requested
728 // stack_size by the size of the guard pages to mimick proper
729 // behaviour.
730 stack_size = align_size_up(stack_size + os::Linux::default_guard_size(thr_type), vm_page_size());
731 pthread_attr_setstacksize(&attr, stack_size);
732
733 // Configure glibc guard page.
734 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
735
736 ThreadState state;
737
738 {
739 pthread_t tid;
740 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
741
742 char buf[64];
743 if (ret == 0) {
744 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
745 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
746 } else {
747 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
748 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
749 }
750
751 pthread_attr_destroy(&attr);
752
753 if (ret != 0) {
754 // Need to clean up stuff we've allocated so far
755 thread->set_osthread(NULL);
756 delete osthread;
757 return false;
758 }
759
760 // Store pthread info into the OSThread
761 osthread->set_pthread_id(tid);
762
763 // Wait until child thread is either initialized or aborted
764 {
765 Monitor* sync_with_child = osthread->startThread_lock();
766 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
767 while ((state = osthread->get_state()) == ALLOCATED) {
768 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
769 }
770 }
771 }
772
773 // Aborted due to thread limit being reached
774 if (state == ZOMBIE) {
775 thread->set_osthread(NULL);
776 delete osthread;
777 return false;
778 }
779
780 // The thread is returned suspended (in state INITIALIZED),
781 // and is started higher up in the call chain
782 assert(state == INITIALIZED, "race condition");
783 return true;
784 }
785
786 /////////////////////////////////////////////////////////////////////////////
787 // attach existing thread
788
789 // bootstrap the main thread
790 bool os::create_main_thread(JavaThread* thread) {
791 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
792 return create_attached_thread(thread);
793 }
794
795 bool os::create_attached_thread(JavaThread* thread) {
796 #ifdef ASSERT
797 thread->verify_not_published();
798 #endif
799
800 // Allocate the OSThread object
801 OSThread* osthread = new OSThread(NULL, NULL);
802
803 if (osthread == NULL) {
804 return false;
805 }
806
807 // Store pthread info into the OSThread
808 osthread->set_thread_id(os::Linux::gettid());
809 osthread->set_pthread_id(::pthread_self());
810
811 // initialize floating point control register
812 os::Linux::init_thread_fpu_state();
813
814 // Initial thread state is RUNNABLE
815 osthread->set_state(RUNNABLE);
816
817 thread->set_osthread(osthread);
818
819 if (UseNUMA) {
820 int lgrp_id = os::numa_get_group_id();
821 if (lgrp_id != -1) {
822 thread->set_lgrp_id(lgrp_id);
823 }
824 }
825
826 if (os::Linux::is_initial_thread()) {
827 // If current thread is initial thread, its stack is mapped on demand,
828 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
829 // the entire stack region to avoid SEGV in stack banging.
830 // It is also useful to get around the heap-stack-gap problem on SuSE
831 // kernel (see 4821821 for details). We first expand stack to the top
832 // of yellow zone, then enable stack yellow zone (order is significant,
833 // enabling yellow zone first will crash JVM on SuSE Linux), so there
834 // is no gap between the last two virtual memory regions.
835
836 JavaThread *jt = (JavaThread *)thread;
837 address addr = jt->stack_reserved_zone_base();
838 assert(addr != NULL, "initialization problem?");
839 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
840
841 osthread->set_expanding_stack();
842 os::Linux::manually_expand_stack(jt, addr);
843 osthread->clear_expanding_stack();
844 }
845
846 // initialize signal mask for this thread
847 // and save the caller's signal mask
848 os::Linux::hotspot_sigmask(thread);
849
850 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
851 os::current_thread_id(), (uintx) pthread_self());
852
853 return true;
854 }
855
856 void os::pd_start_thread(Thread* thread) {
857 OSThread * osthread = thread->osthread();
858 assert(osthread->get_state() != INITIALIZED, "just checking");
859 Monitor* sync_with_child = osthread->startThread_lock();
860 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
861 sync_with_child->notify();
862 }
863
864 // Free Linux resources related to the OSThread
865 void os::free_thread(OSThread* osthread) {
866 assert(osthread != NULL, "osthread not set");
867
868 // We are told to free resources of the argument thread,
869 // but we can only really operate on the current thread.
870 assert(Thread::current()->osthread() == osthread,
871 "os::free_thread but not current thread");
872
873 #ifdef ASSERT
874 sigset_t current;
875 sigemptyset(¤t);
876 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
877 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
878 #endif
879
880 // Restore caller's signal mask
881 sigset_t sigmask = osthread->caller_sigmask();
882 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
883
884 delete osthread;
885 }
886
887 //////////////////////////////////////////////////////////////////////////////
888 // initial thread
889
890 // Check if current thread is the initial thread, similar to Solaris thr_main.
891 bool os::Linux::is_initial_thread(void) {
892 char dummy;
893 // If called before init complete, thread stack bottom will be null.
894 // Can be called if fatal error occurs before initialization.
895 if (initial_thread_stack_bottom() == NULL) return false;
896 assert(initial_thread_stack_bottom() != NULL &&
897 initial_thread_stack_size() != 0,
898 "os::init did not locate initial thread's stack region");
899 if ((address)&dummy >= initial_thread_stack_bottom() &&
900 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
901 return true;
902 } else {
903 return false;
904 }
905 }
906
907 // Find the virtual memory area that contains addr
908 static bool find_vma(address addr, address* vma_low, address* vma_high) {
909 FILE *fp = fopen("/proc/self/maps", "r");
910 if (fp) {
911 address low, high;
912 while (!feof(fp)) {
913 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
914 if (low <= addr && addr < high) {
915 if (vma_low) *vma_low = low;
916 if (vma_high) *vma_high = high;
917 fclose(fp);
918 return true;
919 }
920 }
921 for (;;) {
922 int ch = fgetc(fp);
923 if (ch == EOF || ch == (int)'\n') break;
924 }
925 }
926 fclose(fp);
927 }
928 return false;
929 }
930
931 // Locate initial thread stack. This special handling of initial thread stack
932 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
933 // bogus value for the primordial process thread. While the launcher has created
934 // the VM in a new thread since JDK 6, we still have to allow for the use of the
935 // JNI invocation API from a primordial thread.
936 void os::Linux::capture_initial_stack(size_t max_size) {
937
938 // max_size is either 0 (which means accept OS default for thread stacks) or
939 // a user-specified value known to be at least the minimum needed. If we
940 // are actually on the primordial thread we can make it appear that we have a
941 // smaller max_size stack by inserting the guard pages at that location. But we
942 // cannot do anything to emulate a larger stack than what has been provided by
943 // the OS or threading library. In fact if we try to use a stack greater than
944 // what is set by rlimit then we will crash the hosting process.
945
946 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
947 // If this is "unlimited" then it will be a huge value.
948 struct rlimit rlim;
949 getrlimit(RLIMIT_STACK, &rlim);
950 size_t stack_size = rlim.rlim_cur;
951
952 // 6308388: a bug in ld.so will relocate its own .data section to the
953 // lower end of primordial stack; reduce ulimit -s value a little bit
954 // so we won't install guard page on ld.so's data section.
955 stack_size -= 2 * page_size();
956
957 // Try to figure out where the stack base (top) is. This is harder.
958 //
959 // When an application is started, glibc saves the initial stack pointer in
960 // a global variable "__libc_stack_end", which is then used by system
961 // libraries. __libc_stack_end should be pretty close to stack top. The
962 // variable is available since the very early days. However, because it is
963 // a private interface, it could disappear in the future.
964 //
965 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
966 // to __libc_stack_end, it is very close to stack top, but isn't the real
967 // stack top. Note that /proc may not exist if VM is running as a chroot
968 // program, so reading /proc/<pid>/stat could fail. Also the contents of
969 // /proc/<pid>/stat could change in the future (though unlikely).
970 //
971 // We try __libc_stack_end first. If that doesn't work, look for
972 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
973 // as a hint, which should work well in most cases.
974
975 uintptr_t stack_start;
976
977 // try __libc_stack_end first
978 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
979 if (p && *p) {
980 stack_start = *p;
981 } else {
982 // see if we can get the start_stack field from /proc/self/stat
983 FILE *fp;
984 int pid;
985 char state;
986 int ppid;
987 int pgrp;
988 int session;
989 int nr;
990 int tpgrp;
991 unsigned long flags;
992 unsigned long minflt;
993 unsigned long cminflt;
994 unsigned long majflt;
995 unsigned long cmajflt;
996 unsigned long utime;
997 unsigned long stime;
998 long cutime;
999 long cstime;
1000 long prio;
1001 long nice;
1002 long junk;
1003 long it_real;
1004 uintptr_t start;
1005 uintptr_t vsize;
1006 intptr_t rss;
1007 uintptr_t rsslim;
1008 uintptr_t scodes;
1009 uintptr_t ecode;
1010 int i;
1011
1012 // Figure what the primordial thread stack base is. Code is inspired
1013 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1014 // followed by command name surrounded by parentheses, state, etc.
1015 char stat[2048];
1016 int statlen;
1017
1018 fp = fopen("/proc/self/stat", "r");
1019 if (fp) {
1020 statlen = fread(stat, 1, 2047, fp);
1021 stat[statlen] = '\0';
1022 fclose(fp);
1023
1024 // Skip pid and the command string. Note that we could be dealing with
1025 // weird command names, e.g. user could decide to rename java launcher
1026 // to "java 1.4.2 :)", then the stat file would look like
1027 // 1234 (java 1.4.2 :)) R ... ...
1028 // We don't really need to know the command string, just find the last
1029 // occurrence of ")" and then start parsing from there. See bug 4726580.
1030 char * s = strrchr(stat, ')');
1031
1032 i = 0;
1033 if (s) {
1034 // Skip blank chars
1035 do { s++; } while (s && isspace(*s));
1036
1037 #define _UFM UINTX_FORMAT
1038 #define _DFM INTX_FORMAT
1039
1040 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1041 // 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
1042 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,
1043 &state, // 3 %c
1044 &ppid, // 4 %d
1045 &pgrp, // 5 %d
1046 &session, // 6 %d
1047 &nr, // 7 %d
1048 &tpgrp, // 8 %d
1049 &flags, // 9 %lu
1050 &minflt, // 10 %lu
1051 &cminflt, // 11 %lu
1052 &majflt, // 12 %lu
1053 &cmajflt, // 13 %lu
1054 &utime, // 14 %lu
1055 &stime, // 15 %lu
1056 &cutime, // 16 %ld
1057 &cstime, // 17 %ld
1058 &prio, // 18 %ld
1059 &nice, // 19 %ld
1060 &junk, // 20 %ld
1061 &it_real, // 21 %ld
1062 &start, // 22 UINTX_FORMAT
1063 &vsize, // 23 UINTX_FORMAT
1064 &rss, // 24 INTX_FORMAT
1065 &rsslim, // 25 UINTX_FORMAT
1066 &scodes, // 26 UINTX_FORMAT
1067 &ecode, // 27 UINTX_FORMAT
1068 &stack_start); // 28 UINTX_FORMAT
1069 }
1070
1071 #undef _UFM
1072 #undef _DFM
1073
1074 if (i != 28 - 2) {
1075 assert(false, "Bad conversion from /proc/self/stat");
1076 // product mode - assume we are the initial thread, good luck in the
1077 // embedded case.
1078 warning("Can't detect initial thread stack location - bad conversion");
1079 stack_start = (uintptr_t) &rlim;
1080 }
1081 } else {
1082 // For some reason we can't open /proc/self/stat (for example, running on
1083 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1084 // most cases, so don't abort:
1085 warning("Can't detect initial thread stack location - no /proc/self/stat");
1086 stack_start = (uintptr_t) &rlim;
1087 }
1088 }
1089
1090 // Now we have a pointer (stack_start) very close to the stack top, the
1091 // next thing to do is to figure out the exact location of stack top. We
1092 // can find out the virtual memory area that contains stack_start by
1093 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1094 // and its upper limit is the real stack top. (again, this would fail if
1095 // running inside chroot, because /proc may not exist.)
1096
1097 uintptr_t stack_top;
1098 address low, high;
1099 if (find_vma((address)stack_start, &low, &high)) {
1100 // success, "high" is the true stack top. (ignore "low", because initial
1101 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1102 stack_top = (uintptr_t)high;
1103 } else {
1104 // failed, likely because /proc/self/maps does not exist
1105 warning("Can't detect initial thread stack location - find_vma failed");
1106 // best effort: stack_start is normally within a few pages below the real
1107 // stack top, use it as stack top, and reduce stack size so we won't put
1108 // guard page outside stack.
1109 stack_top = stack_start;
1110 stack_size -= 16 * page_size();
1111 }
1112
1113 // stack_top could be partially down the page so align it
1114 stack_top = align_size_up(stack_top, page_size());
1115
1116 // Allowed stack value is minimum of max_size and what we derived from rlimit
1117 if (max_size > 0) {
1118 _initial_thread_stack_size = MIN2(max_size, stack_size);
1119 } else {
1120 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1121 // clamp it at 8MB as we do on Solaris
1122 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1123 }
1124 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1125 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1126
1127 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1128
1129 if (log_is_enabled(Info, os, thread)) {
1130 // See if we seem to be on primordial process thread
1131 bool primordial = uintptr_t(&rlim) > uintptr_t(_initial_thread_stack_bottom) &&
1132 uintptr_t(&rlim) < stack_top;
1133
1134 log_info(os, thread)("Capturing initial stack in %s thread: req. size: " SIZE_FORMAT "K, actual size: "
1135 SIZE_FORMAT "K, top=" INTPTR_FORMAT ", bottom=" INTPTR_FORMAT,
1136 primordial ? "primordial" : "user", max_size / K, _initial_thread_stack_size / K,
1137 stack_top, intptr_t(_initial_thread_stack_bottom));
1138 }
1139 }
1140
1141 ////////////////////////////////////////////////////////////////////////////////
1142 // time support
1143
1144 // Time since start-up in seconds to a fine granularity.
1145 // Used by VMSelfDestructTimer and the MemProfiler.
1146 double os::elapsedTime() {
1147
1148 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1149 }
1150
1151 jlong os::elapsed_counter() {
1152 return javaTimeNanos() - initial_time_count;
1153 }
1154
1155 jlong os::elapsed_frequency() {
1156 return NANOSECS_PER_SEC; // nanosecond resolution
1157 }
1158
1159 bool os::supports_vtime() { return true; }
1160 bool os::enable_vtime() { return false; }
1161 bool os::vtime_enabled() { return false; }
1162
1163 double os::elapsedVTime() {
1164 struct rusage usage;
1165 int retval = getrusage(RUSAGE_THREAD, &usage);
1166 if (retval == 0) {
1167 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);
1168 } else {
1169 // better than nothing, but not much
1170 return elapsedTime();
1171 }
1172 }
1173
1174 jlong os::javaTimeMillis() {
1175 timeval time;
1176 int status = gettimeofday(&time, NULL);
1177 assert(status != -1, "linux error");
1178 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1179 }
1180
1181 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1182 timeval time;
1183 int status = gettimeofday(&time, NULL);
1184 assert(status != -1, "linux error");
1185 seconds = jlong(time.tv_sec);
1186 nanos = jlong(time.tv_usec) * 1000;
1187 }
1188
1189
1190 #ifndef CLOCK_MONOTONIC
1191 #define CLOCK_MONOTONIC (1)
1192 #endif
1193
1194 void os::Linux::clock_init() {
1195 // we do dlopen's in this particular order due to bug in linux
1196 // dynamical loader (see 6348968) leading to crash on exit
1197 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1198 if (handle == NULL) {
1199 handle = dlopen("librt.so", RTLD_LAZY);
1200 }
1201
1202 if (handle) {
1203 int (*clock_getres_func)(clockid_t, struct timespec*) =
1204 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1205 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1206 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1207 if (clock_getres_func && clock_gettime_func) {
1208 // See if monotonic clock is supported by the kernel. Note that some
1209 // early implementations simply return kernel jiffies (updated every
1210 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1211 // for nano time (though the monotonic property is still nice to have).
1212 // It's fixed in newer kernels, however clock_getres() still returns
1213 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1214 // resolution for now. Hopefully as people move to new kernels, this
1215 // won't be a problem.
1216 struct timespec res;
1217 struct timespec tp;
1218 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1219 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1220 // yes, monotonic clock is supported
1221 _clock_gettime = clock_gettime_func;
1222 return;
1223 } else {
1224 // close librt if there is no monotonic clock
1225 dlclose(handle);
1226 }
1227 }
1228 }
1229 warning("No monotonic clock was available - timed services may " \
1230 "be adversely affected if the time-of-day clock changes");
1231 }
1232
1233 #ifndef SYS_clock_getres
1234 #if defined(X86) || defined(PPC64) || defined(S390)
1235 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261)
1236 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1237 #else
1238 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1239 #define sys_clock_getres(x,y) -1
1240 #endif
1241 #else
1242 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1243 #endif
1244
1245 void os::Linux::fast_thread_clock_init() {
1246 if (!UseLinuxPosixThreadCPUClocks) {
1247 return;
1248 }
1249 clockid_t clockid;
1250 struct timespec tp;
1251 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1252 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1253
1254 // Switch to using fast clocks for thread cpu time if
1255 // the sys_clock_getres() returns 0 error code.
1256 // Note, that some kernels may support the current thread
1257 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1258 // returned by the pthread_getcpuclockid().
1259 // If the fast Posix clocks are supported then the sys_clock_getres()
1260 // must return at least tp.tv_sec == 0 which means a resolution
1261 // better than 1 sec. This is extra check for reliability.
1262
1263 if (pthread_getcpuclockid_func &&
1264 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1265 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1266 _supports_fast_thread_cpu_time = true;
1267 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1268 }
1269 }
1270
1271 jlong os::javaTimeNanos() {
1272 if (os::supports_monotonic_clock()) {
1273 struct timespec tp;
1274 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1275 assert(status == 0, "gettime error");
1276 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1277 return result;
1278 } else {
1279 timeval time;
1280 int status = gettimeofday(&time, NULL);
1281 assert(status != -1, "linux error");
1282 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1283 return 1000 * usecs;
1284 }
1285 }
1286
1287 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1288 if (os::supports_monotonic_clock()) {
1289 info_ptr->max_value = ALL_64_BITS;
1290
1291 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1292 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1293 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1294 } else {
1295 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1296 info_ptr->max_value = ALL_64_BITS;
1297
1298 // gettimeofday is a real time clock so it skips
1299 info_ptr->may_skip_backward = true;
1300 info_ptr->may_skip_forward = true;
1301 }
1302
1303 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1304 }
1305
1306 // Return the real, user, and system times in seconds from an
1307 // arbitrary fixed point in the past.
1308 bool os::getTimesSecs(double* process_real_time,
1309 double* process_user_time,
1310 double* process_system_time) {
1311 struct tms ticks;
1312 clock_t real_ticks = times(&ticks);
1313
1314 if (real_ticks == (clock_t) (-1)) {
1315 return false;
1316 } else {
1317 double ticks_per_second = (double) clock_tics_per_sec;
1318 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1319 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1320 *process_real_time = ((double) real_ticks) / ticks_per_second;
1321
1322 return true;
1323 }
1324 }
1325
1326
1327 char * os::local_time_string(char *buf, size_t buflen) {
1328 struct tm t;
1329 time_t long_time;
1330 time(&long_time);
1331 localtime_r(&long_time, &t);
1332 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1333 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1334 t.tm_hour, t.tm_min, t.tm_sec);
1335 return buf;
1336 }
1337
1338 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1339 return localtime_r(clock, res);
1340 }
1341
1342 ////////////////////////////////////////////////////////////////////////////////
1343 // runtime exit support
1344
1345 // Note: os::shutdown() might be called very early during initialization, or
1346 // called from signal handler. Before adding something to os::shutdown(), make
1347 // sure it is async-safe and can handle partially initialized VM.
1348 void os::shutdown() {
1349
1350 // allow PerfMemory to attempt cleanup of any persistent resources
1351 perfMemory_exit();
1352
1353 // needs to remove object in file system
1354 AttachListener::abort();
1355
1356 // flush buffered output, finish log files
1357 ostream_abort();
1358
1359 // Check for abort hook
1360 abort_hook_t abort_hook = Arguments::abort_hook();
1361 if (abort_hook != NULL) {
1362 abort_hook();
1363 }
1364
1365 }
1366
1367 // Note: os::abort() might be called very early during initialization, or
1368 // called from signal handler. Before adding something to os::abort(), make
1369 // sure it is async-safe and can handle partially initialized VM.
1370 void os::abort(bool dump_core, void* siginfo, const void* context) {
1371 os::shutdown();
1372 if (dump_core) {
1373 #ifndef PRODUCT
1374 fdStream out(defaultStream::output_fd());
1375 out.print_raw("Current thread is ");
1376 char buf[16];
1377 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1378 out.print_raw_cr(buf);
1379 out.print_raw_cr("Dumping core ...");
1380 #endif
1381 ::abort(); // dump core
1382 }
1383
1384 ::exit(1);
1385 }
1386
1387 // Die immediately, no exit hook, no abort hook, no cleanup.
1388 void os::die() {
1389 ::abort();
1390 }
1391
1392
1393 // This method is a copy of JDK's sysGetLastErrorString
1394 // from src/solaris/hpi/src/system_md.c
1395
1396 size_t os::lasterror(char *buf, size_t len) {
1397 if (errno == 0) return 0;
1398
1399 const char *s = os::strerror(errno);
1400 size_t n = ::strlen(s);
1401 if (n >= len) {
1402 n = len - 1;
1403 }
1404 ::strncpy(buf, s, n);
1405 buf[n] = '\0';
1406 return n;
1407 }
1408
1409 // thread_id is kernel thread id (similar to Solaris LWP id)
1410 intx os::current_thread_id() { return os::Linux::gettid(); }
1411 int os::current_process_id() {
1412 return ::getpid();
1413 }
1414
1415 // DLL functions
1416
1417 const char* os::dll_file_extension() { return ".so"; }
1418
1419 // This must be hard coded because it's the system's temporary
1420 // directory not the java application's temp directory, ala java.io.tmpdir.
1421 const char* os::get_temp_directory() { return "/tmp"; }
1422
1423 static bool file_exists(const char* filename) {
1424 struct stat statbuf;
1425 if (filename == NULL || strlen(filename) == 0) {
1426 return false;
1427 }
1428 return os::stat(filename, &statbuf) == 0;
1429 }
1430
1431 bool os::dll_build_name(char* buffer, size_t buflen,
1432 const char* pname, const char* fname) {
1433 bool retval = false;
1434 // Copied from libhpi
1435 const size_t pnamelen = pname ? strlen(pname) : 0;
1436
1437 // Return error on buffer overflow.
1438 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1439 return retval;
1440 }
1441
1442 if (pnamelen == 0) {
1443 snprintf(buffer, buflen, "lib%s.so", fname);
1444 retval = true;
1445 } else if (strchr(pname, *os::path_separator()) != NULL) {
1446 int n;
1447 char** pelements = split_path(pname, &n);
1448 if (pelements == NULL) {
1449 return false;
1450 }
1451 for (int i = 0; i < n; i++) {
1452 // Really shouldn't be NULL, but check can't hurt
1453 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1454 continue; // skip the empty path values
1455 }
1456 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1457 if (file_exists(buffer)) {
1458 retval = true;
1459 break;
1460 }
1461 }
1462 // release the storage
1463 for (int i = 0; i < n; i++) {
1464 if (pelements[i] != NULL) {
1465 FREE_C_HEAP_ARRAY(char, pelements[i]);
1466 }
1467 }
1468 if (pelements != NULL) {
1469 FREE_C_HEAP_ARRAY(char*, pelements);
1470 }
1471 } else {
1472 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1473 retval = true;
1474 }
1475 return retval;
1476 }
1477
1478 // check if addr is inside libjvm.so
1479 bool os::address_is_in_vm(address addr) {
1480 static address libjvm_base_addr;
1481 Dl_info dlinfo;
1482
1483 if (libjvm_base_addr == NULL) {
1484 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1485 libjvm_base_addr = (address)dlinfo.dli_fbase;
1486 }
1487 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1488 }
1489
1490 if (dladdr((void *)addr, &dlinfo) != 0) {
1491 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1492 }
1493
1494 return false;
1495 }
1496
1497 bool os::dll_address_to_function_name(address addr, char *buf,
1498 int buflen, int *offset,
1499 bool demangle) {
1500 // buf is not optional, but offset is optional
1501 assert(buf != NULL, "sanity check");
1502
1503 Dl_info dlinfo;
1504
1505 if (dladdr((void*)addr, &dlinfo) != 0) {
1506 // see if we have a matching symbol
1507 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1508 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1509 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1510 }
1511 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1512 return true;
1513 }
1514 // no matching symbol so try for just file info
1515 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1516 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1517 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1518 return true;
1519 }
1520 }
1521 }
1522
1523 buf[0] = '\0';
1524 if (offset != NULL) *offset = -1;
1525 return false;
1526 }
1527
1528 struct _address_to_library_name {
1529 address addr; // input : memory address
1530 size_t buflen; // size of fname
1531 char* fname; // output: library name
1532 address base; // library base addr
1533 };
1534
1535 static int address_to_library_name_callback(struct dl_phdr_info *info,
1536 size_t size, void *data) {
1537 int i;
1538 bool found = false;
1539 address libbase = NULL;
1540 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1541
1542 // iterate through all loadable segments
1543 for (i = 0; i < info->dlpi_phnum; i++) {
1544 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1545 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1546 // base address of a library is the lowest address of its loaded
1547 // segments.
1548 if (libbase == NULL || libbase > segbase) {
1549 libbase = segbase;
1550 }
1551 // see if 'addr' is within current segment
1552 if (segbase <= d->addr &&
1553 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1554 found = true;
1555 }
1556 }
1557 }
1558
1559 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1560 // so dll_address_to_library_name() can fall through to use dladdr() which
1561 // can figure out executable name from argv[0].
1562 if (found && info->dlpi_name && info->dlpi_name[0]) {
1563 d->base = libbase;
1564 if (d->fname) {
1565 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1566 }
1567 return 1;
1568 }
1569 return 0;
1570 }
1571
1572 bool os::dll_address_to_library_name(address addr, char* buf,
1573 int buflen, int* offset) {
1574 // buf is not optional, but offset is optional
1575 assert(buf != NULL, "sanity check");
1576
1577 Dl_info dlinfo;
1578 struct _address_to_library_name data;
1579
1580 // There is a bug in old glibc dladdr() implementation that it could resolve
1581 // to wrong library name if the .so file has a base address != NULL. Here
1582 // we iterate through the program headers of all loaded libraries to find
1583 // out which library 'addr' really belongs to. This workaround can be
1584 // removed once the minimum requirement for glibc is moved to 2.3.x.
1585 data.addr = addr;
1586 data.fname = buf;
1587 data.buflen = buflen;
1588 data.base = NULL;
1589 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1590
1591 if (rslt) {
1592 // buf already contains library name
1593 if (offset) *offset = addr - data.base;
1594 return true;
1595 }
1596 if (dladdr((void*)addr, &dlinfo) != 0) {
1597 if (dlinfo.dli_fname != NULL) {
1598 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1599 }
1600 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1601 *offset = addr - (address)dlinfo.dli_fbase;
1602 }
1603 return true;
1604 }
1605
1606 buf[0] = '\0';
1607 if (offset) *offset = -1;
1608 return false;
1609 }
1610
1611 // Loads .dll/.so and
1612 // in case of error it checks if .dll/.so was built for the
1613 // same architecture as Hotspot is running on
1614
1615
1616 // Remember the stack's state. The Linux dynamic linker will change
1617 // the stack to 'executable' at most once, so we must safepoint only once.
1618 bool os::Linux::_stack_is_executable = false;
1619
1620 // VM operation that loads a library. This is necessary if stack protection
1621 // of the Java stacks can be lost during loading the library. If we
1622 // do not stop the Java threads, they can stack overflow before the stacks
1623 // are protected again.
1624 class VM_LinuxDllLoad: public VM_Operation {
1625 private:
1626 const char *_filename;
1627 char *_ebuf;
1628 int _ebuflen;
1629 void *_lib;
1630 public:
1631 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1632 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1633 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1634 void doit() {
1635 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1636 os::Linux::_stack_is_executable = true;
1637 }
1638 void* loaded_library() { return _lib; }
1639 };
1640
1641 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1642 void * result = NULL;
1643 bool load_attempted = false;
1644
1645 // Check whether the library to load might change execution rights
1646 // of the stack. If they are changed, the protection of the stack
1647 // guard pages will be lost. We need a safepoint to fix this.
1648 //
1649 // See Linux man page execstack(8) for more info.
1650 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1651 ElfFile ef(filename);
1652 if (!ef.specifies_noexecstack()) {
1653 if (!is_init_completed()) {
1654 os::Linux::_stack_is_executable = true;
1655 // This is OK - No Java threads have been created yet, and hence no
1656 // stack guard pages to fix.
1657 //
1658 // This should happen only when you are building JDK7 using a very
1659 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1660 //
1661 // Dynamic loader will make all stacks executable after
1662 // this function returns, and will not do that again.
1663 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1664 } else {
1665 warning("You have loaded library %s which might have disabled stack guard. "
1666 "The VM will try to fix the stack guard now.\n"
1667 "It's highly recommended that you fix the library with "
1668 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1669 filename);
1670
1671 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1672 JavaThread *jt = JavaThread::current();
1673 if (jt->thread_state() != _thread_in_native) {
1674 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1675 // that requires ExecStack. Cannot enter safe point. Let's give up.
1676 warning("Unable to fix stack guard. Giving up.");
1677 } else {
1678 if (!LoadExecStackDllInVMThread) {
1679 // This is for the case where the DLL has an static
1680 // constructor function that executes JNI code. We cannot
1681 // load such DLLs in the VMThread.
1682 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1683 }
1684
1685 ThreadInVMfromNative tiv(jt);
1686 debug_only(VMNativeEntryWrapper vew;)
1687
1688 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1689 VMThread::execute(&op);
1690 if (LoadExecStackDllInVMThread) {
1691 result = op.loaded_library();
1692 }
1693 load_attempted = true;
1694 }
1695 }
1696 }
1697 }
1698
1699 if (!load_attempted) {
1700 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1701 }
1702
1703 if (result != NULL) {
1704 // Successful loading
1705 return result;
1706 }
1707
1708 Elf32_Ehdr elf_head;
1709 int diag_msg_max_length=ebuflen-strlen(ebuf);
1710 char* diag_msg_buf=ebuf+strlen(ebuf);
1711
1712 if (diag_msg_max_length==0) {
1713 // No more space in ebuf for additional diagnostics message
1714 return NULL;
1715 }
1716
1717
1718 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1719
1720 if (file_descriptor < 0) {
1721 // Can't open library, report dlerror() message
1722 return NULL;
1723 }
1724
1725 bool failed_to_read_elf_head=
1726 (sizeof(elf_head)!=
1727 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1728
1729 ::close(file_descriptor);
1730 if (failed_to_read_elf_head) {
1731 // file i/o error - report dlerror() msg
1732 return NULL;
1733 }
1734
1735 typedef struct {
1736 Elf32_Half code; // Actual value as defined in elf.h
1737 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1738 unsigned char elf_class; // 32 or 64 bit
1739 unsigned char endianess; // MSB or LSB
1740 char* name; // String representation
1741 } arch_t;
1742
1743 #ifndef EM_486
1744 #define EM_486 6 /* Intel 80486 */
1745 #endif
1746 #ifndef EM_AARCH64
1747 #define EM_AARCH64 183 /* ARM AARCH64 */
1748 #endif
1749
1750 static const arch_t arch_array[]={
1751 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1752 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1753 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1754 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1755 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1756 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1757 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1758 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1759 #if defined(VM_LITTLE_ENDIAN)
1760 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1761 #else
1762 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1763 #endif
1764 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1765 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1766 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1767 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1768 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1769 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1770 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1771 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1772 };
1773
1774 #if (defined IA32)
1775 static Elf32_Half running_arch_code=EM_386;
1776 #elif (defined AMD64)
1777 static Elf32_Half running_arch_code=EM_X86_64;
1778 #elif (defined IA64)
1779 static Elf32_Half running_arch_code=EM_IA_64;
1780 #elif (defined __sparc) && (defined _LP64)
1781 static Elf32_Half running_arch_code=EM_SPARCV9;
1782 #elif (defined __sparc) && (!defined _LP64)
1783 static Elf32_Half running_arch_code=EM_SPARC;
1784 #elif (defined __powerpc64__)
1785 static Elf32_Half running_arch_code=EM_PPC64;
1786 #elif (defined __powerpc__)
1787 static Elf32_Half running_arch_code=EM_PPC;
1788 #elif (defined AARCH64)
1789 static Elf32_Half running_arch_code=EM_AARCH64;
1790 #elif (defined ARM)
1791 static Elf32_Half running_arch_code=EM_ARM;
1792 #elif (defined S390)
1793 static Elf32_Half running_arch_code=EM_S390;
1794 #elif (defined ALPHA)
1795 static Elf32_Half running_arch_code=EM_ALPHA;
1796 #elif (defined MIPSEL)
1797 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1798 #elif (defined PARISC)
1799 static Elf32_Half running_arch_code=EM_PARISC;
1800 #elif (defined MIPS)
1801 static Elf32_Half running_arch_code=EM_MIPS;
1802 #elif (defined M68K)
1803 static Elf32_Half running_arch_code=EM_68K;
1804 #else
1805 #error Method os::dll_load requires that one of following is defined:\
1806 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc
1807 #endif
1808
1809 // Identify compatability class for VM's architecture and library's architecture
1810 // Obtain string descriptions for architectures
1811
1812 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1813 int running_arch_index=-1;
1814
1815 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1816 if (running_arch_code == arch_array[i].code) {
1817 running_arch_index = i;
1818 }
1819 if (lib_arch.code == arch_array[i].code) {
1820 lib_arch.compat_class = arch_array[i].compat_class;
1821 lib_arch.name = arch_array[i].name;
1822 }
1823 }
1824
1825 assert(running_arch_index != -1,
1826 "Didn't find running architecture code (running_arch_code) in arch_array");
1827 if (running_arch_index == -1) {
1828 // Even though running architecture detection failed
1829 // we may still continue with reporting dlerror() message
1830 return NULL;
1831 }
1832
1833 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1834 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1835 return NULL;
1836 }
1837
1838 #ifndef S390
1839 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1840 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1841 return NULL;
1842 }
1843 #endif // !S390
1844
1845 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1846 if (lib_arch.name!=NULL) {
1847 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1848 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1849 lib_arch.name, arch_array[running_arch_index].name);
1850 } else {
1851 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1852 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1853 lib_arch.code,
1854 arch_array[running_arch_index].name);
1855 }
1856 }
1857
1858 return NULL;
1859 }
1860
1861 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1862 int ebuflen) {
1863 void * result = ::dlopen(filename, RTLD_LAZY);
1864 if (result == NULL) {
1865 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1866 ebuf[ebuflen-1] = '\0';
1867 }
1868 return result;
1869 }
1870
1871 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1872 int ebuflen) {
1873 void * result = NULL;
1874 if (LoadExecStackDllInVMThread) {
1875 result = dlopen_helper(filename, ebuf, ebuflen);
1876 }
1877
1878 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1879 // library that requires an executable stack, or which does not have this
1880 // stack attribute set, dlopen changes the stack attribute to executable. The
1881 // read protection of the guard pages gets lost.
1882 //
1883 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1884 // may have been queued at the same time.
1885
1886 if (!_stack_is_executable) {
1887 JavaThread *jt = Threads::first();
1888
1889 while (jt) {
1890 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1891 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1892 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1893 warning("Attempt to reguard stack yellow zone failed.");
1894 }
1895 }
1896 jt = jt->next();
1897 }
1898 }
1899
1900 return result;
1901 }
1902
1903 void* os::dll_lookup(void* handle, const char* name) {
1904 void* res = dlsym(handle, name);
1905 return res;
1906 }
1907
1908 void* os::get_default_process_handle() {
1909 return (void*)::dlopen(NULL, RTLD_LAZY);
1910 }
1911
1912 static bool _print_ascii_file(const char* filename, outputStream* st) {
1913 int fd = ::open(filename, O_RDONLY);
1914 if (fd == -1) {
1915 return false;
1916 }
1917
1918 char buf[33];
1919 int bytes;
1920 buf[32] = '\0';
1921 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1922 st->print_raw(buf, bytes);
1923 }
1924
1925 ::close(fd);
1926
1927 return true;
1928 }
1929
1930 void os::print_dll_info(outputStream *st) {
1931 st->print_cr("Dynamic libraries:");
1932
1933 char fname[32];
1934 pid_t pid = os::Linux::gettid();
1935
1936 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1937
1938 if (!_print_ascii_file(fname, st)) {
1939 st->print("Can not get library information for pid = %d\n", pid);
1940 }
1941 }
1942
1943 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1944 FILE *procmapsFile = NULL;
1945
1946 // Open the procfs maps file for the current process
1947 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1948 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1949 char line[PATH_MAX + 100];
1950
1951 // Read line by line from 'file'
1952 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1953 u8 base, top, offset, inode;
1954 char permissions[5];
1955 char device[6];
1956 char name[PATH_MAX + 1];
1957
1958 // Parse fields from line
1959 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1960 &base, &top, permissions, &offset, device, &inode, name);
1961
1962 // Filter by device id '00:00' so that we only get file system mapped files.
1963 if (strcmp(device, "00:00") != 0) {
1964
1965 // Call callback with the fields of interest
1966 if(callback(name, (address)base, (address)top, param)) {
1967 // Oops abort, callback aborted
1968 fclose(procmapsFile);
1969 return 1;
1970 }
1971 }
1972 }
1973 fclose(procmapsFile);
1974 }
1975 return 0;
1976 }
1977
1978 void os::print_os_info_brief(outputStream* st) {
1979 os::Linux::print_distro_info(st);
1980
1981 os::Posix::print_uname_info(st);
1982
1983 os::Linux::print_libversion_info(st);
1984
1985 }
1986
1987 void os::print_os_info(outputStream* st) {
1988 st->print("OS:");
1989
1990 os::Linux::print_distro_info(st);
1991
1992 os::Posix::print_uname_info(st);
1993
1994 // Print warning if unsafe chroot environment detected
1995 if (unsafe_chroot_detected) {
1996 st->print("WARNING!! ");
1997 st->print_cr("%s", unstable_chroot_error);
1998 }
1999
2000 os::Linux::print_libversion_info(st);
2001
2002 os::Posix::print_rlimit_info(st);
2003
2004 os::Posix::print_load_average(st);
2005
2006 os::Linux::print_full_memory_info(st);
2007 }
2008
2009 // Try to identify popular distros.
2010 // Most Linux distributions have a /etc/XXX-release file, which contains
2011 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2012 // file that also contains the OS version string. Some have more than one
2013 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2014 // /etc/redhat-release.), so the order is important.
2015 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2016 // their own specific XXX-release file as well as a redhat-release file.
2017 // Because of this the XXX-release file needs to be searched for before the
2018 // redhat-release file.
2019 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2020 // search for redhat-release / SuSE-release needs to be before lsb-release.
2021 // Since the lsb-release file is the new standard it needs to be searched
2022 // before the older style release files.
2023 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2024 // next to last resort. The os-release file is a new standard that contains
2025 // distribution information and the system-release file seems to be an old
2026 // standard that has been replaced by the lsb-release and os-release files.
2027 // Searching for the debian_version file is the last resort. It contains
2028 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2029 // "Debian " is printed before the contents of the debian_version file.
2030
2031 const char* distro_files[] = {
2032 "/etc/oracle-release",
2033 "/etc/mandriva-release",
2034 "/etc/mandrake-release",
2035 "/etc/sun-release",
2036 "/etc/redhat-release",
2037 "/etc/SuSE-release",
2038 "/etc/lsb-release",
2039 "/etc/turbolinux-release",
2040 "/etc/gentoo-release",
2041 "/etc/ltib-release",
2042 "/etc/angstrom-version",
2043 "/etc/system-release",
2044 "/etc/os-release",
2045 NULL };
2046
2047 void os::Linux::print_distro_info(outputStream* st) {
2048 for (int i = 0;; i++) {
2049 const char* file = distro_files[i];
2050 if (file == NULL) {
2051 break; // done
2052 }
2053 // If file prints, we found it.
2054 if (_print_ascii_file(file, st)) {
2055 return;
2056 }
2057 }
2058
2059 if (file_exists("/etc/debian_version")) {
2060 st->print("Debian ");
2061 _print_ascii_file("/etc/debian_version", st);
2062 } else {
2063 st->print("Linux");
2064 }
2065 st->cr();
2066 }
2067
2068 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2069 char buf[256];
2070 while (fgets(buf, sizeof(buf), fp)) {
2071 // Edit out extra stuff in expected format
2072 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2073 char* ptr = strstr(buf, "\""); // the name is in quotes
2074 if (ptr != NULL) {
2075 ptr++; // go beyond first quote
2076 char* nl = strchr(ptr, '\"');
2077 if (nl != NULL) *nl = '\0';
2078 strncpy(distro, ptr, length);
2079 } else {
2080 ptr = strstr(buf, "=");
2081 ptr++; // go beyond equals then
2082 char* nl = strchr(ptr, '\n');
2083 if (nl != NULL) *nl = '\0';
2084 strncpy(distro, ptr, length);
2085 }
2086 return;
2087 } else if (get_first_line) {
2088 char* nl = strchr(buf, '\n');
2089 if (nl != NULL) *nl = '\0';
2090 strncpy(distro, buf, length);
2091 return;
2092 }
2093 }
2094 // print last line and close
2095 char* nl = strchr(buf, '\n');
2096 if (nl != NULL) *nl = '\0';
2097 strncpy(distro, buf, length);
2098 }
2099
2100 static void parse_os_info(char* distro, size_t length, const char* file) {
2101 FILE* fp = fopen(file, "r");
2102 if (fp != NULL) {
2103 // if suse format, print out first line
2104 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2105 parse_os_info_helper(fp, distro, length, get_first_line);
2106 fclose(fp);
2107 }
2108 }
2109
2110 void os::get_summary_os_info(char* buf, size_t buflen) {
2111 for (int i = 0;; i++) {
2112 const char* file = distro_files[i];
2113 if (file == NULL) {
2114 break; // ran out of distro_files
2115 }
2116 if (file_exists(file)) {
2117 parse_os_info(buf, buflen, file);
2118 return;
2119 }
2120 }
2121 // special case for debian
2122 if (file_exists("/etc/debian_version")) {
2123 strncpy(buf, "Debian ", buflen);
2124 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2125 } else {
2126 strncpy(buf, "Linux", buflen);
2127 }
2128 }
2129
2130 void os::Linux::print_libversion_info(outputStream* st) {
2131 // libc, pthread
2132 st->print("libc:");
2133 st->print("%s ", os::Linux::glibc_version());
2134 st->print("%s ", os::Linux::libpthread_version());
2135 st->cr();
2136 }
2137
2138 void os::Linux::print_full_memory_info(outputStream* st) {
2139 st->print("\n/proc/meminfo:\n");
2140 _print_ascii_file("/proc/meminfo", st);
2141 st->cr();
2142 }
2143
2144 void os::print_memory_info(outputStream* st) {
2145
2146 st->print("Memory:");
2147 st->print(" %dk page", os::vm_page_size()>>10);
2148
2149 // values in struct sysinfo are "unsigned long"
2150 struct sysinfo si;
2151 sysinfo(&si);
2152
2153 st->print(", physical " UINT64_FORMAT "k",
2154 os::physical_memory() >> 10);
2155 st->print("(" UINT64_FORMAT "k free)",
2156 os::available_memory() >> 10);
2157 st->print(", swap " UINT64_FORMAT "k",
2158 ((jlong)si.totalswap * si.mem_unit) >> 10);
2159 st->print("(" UINT64_FORMAT "k free)",
2160 ((jlong)si.freeswap * si.mem_unit) >> 10);
2161 st->cr();
2162 }
2163
2164 // Print the first "model name" line and the first "flags" line
2165 // that we find and nothing more. We assume "model name" comes
2166 // before "flags" so if we find a second "model name", then the
2167 // "flags" field is considered missing.
2168 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2169 #if defined(IA32) || defined(AMD64)
2170 // Other platforms have less repetitive cpuinfo files
2171 FILE *fp = fopen("/proc/cpuinfo", "r");
2172 if (fp) {
2173 while (!feof(fp)) {
2174 if (fgets(buf, buflen, fp)) {
2175 // Assume model name comes before flags
2176 bool model_name_printed = false;
2177 if (strstr(buf, "model name") != NULL) {
2178 if (!model_name_printed) {
2179 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2180 st->print_raw(buf);
2181 model_name_printed = true;
2182 } else {
2183 // model name printed but not flags? Odd, just return
2184 fclose(fp);
2185 return true;
2186 }
2187 }
2188 // print the flags line too
2189 if (strstr(buf, "flags") != NULL) {
2190 st->print_raw(buf);
2191 fclose(fp);
2192 return true;
2193 }
2194 }
2195 }
2196 fclose(fp);
2197 }
2198 #endif // x86 platforms
2199 return false;
2200 }
2201
2202 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2203 // Only print the model name if the platform provides this as a summary
2204 if (!print_model_name_and_flags(st, buf, buflen)) {
2205 st->print("\n/proc/cpuinfo:\n");
2206 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2207 st->print_cr(" <Not Available>");
2208 }
2209 }
2210 }
2211
2212 #if defined(AMD64) || defined(IA32) || defined(X32)
2213 const char* search_string = "model name";
2214 #elif defined(PPC64)
2215 const char* search_string = "cpu";
2216 #elif defined(S390)
2217 const char* search_string = "processor";
2218 #elif defined(SPARC)
2219 const char* search_string = "cpu";
2220 #else
2221 const char* search_string = "Processor";
2222 #endif
2223
2224 // Parses the cpuinfo file for string representing the model name.
2225 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2226 FILE* fp = fopen("/proc/cpuinfo", "r");
2227 if (fp != NULL) {
2228 while (!feof(fp)) {
2229 char buf[256];
2230 if (fgets(buf, sizeof(buf), fp)) {
2231 char* start = strstr(buf, search_string);
2232 if (start != NULL) {
2233 char *ptr = start + strlen(search_string);
2234 char *end = buf + strlen(buf);
2235 while (ptr != end) {
2236 // skip whitespace and colon for the rest of the name.
2237 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2238 break;
2239 }
2240 ptr++;
2241 }
2242 if (ptr != end) {
2243 // reasonable string, get rid of newline and keep the rest
2244 char* nl = strchr(buf, '\n');
2245 if (nl != NULL) *nl = '\0';
2246 strncpy(cpuinfo, ptr, length);
2247 fclose(fp);
2248 return;
2249 }
2250 }
2251 }
2252 }
2253 fclose(fp);
2254 }
2255 // cpuinfo not found or parsing failed, just print generic string. The entire
2256 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2257 #if defined(AARCH64)
2258 strncpy(cpuinfo, "AArch64", length);
2259 #elif defined(AMD64)
2260 strncpy(cpuinfo, "x86_64", length);
2261 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2262 strncpy(cpuinfo, "ARM", length);
2263 #elif defined(IA32)
2264 strncpy(cpuinfo, "x86_32", length);
2265 #elif defined(IA64)
2266 strncpy(cpuinfo, "IA64", length);
2267 #elif defined(PPC)
2268 strncpy(cpuinfo, "PPC64", length);
2269 #elif defined(S390)
2270 strncpy(cpuinfo, "S390", length);
2271 #elif defined(SPARC)
2272 strncpy(cpuinfo, "sparcv9", length);
2273 #elif defined(ZERO_LIBARCH)
2274 strncpy(cpuinfo, ZERO_LIBARCH, length);
2275 #else
2276 strncpy(cpuinfo, "unknown", length);
2277 #endif
2278 }
2279
2280 static void print_signal_handler(outputStream* st, int sig,
2281 char* buf, size_t buflen);
2282
2283 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2284 st->print_cr("Signal Handlers:");
2285 print_signal_handler(st, SIGSEGV, buf, buflen);
2286 print_signal_handler(st, SIGBUS , buf, buflen);
2287 print_signal_handler(st, SIGFPE , buf, buflen);
2288 print_signal_handler(st, SIGPIPE, buf, buflen);
2289 print_signal_handler(st, SIGXFSZ, buf, buflen);
2290 print_signal_handler(st, SIGILL , buf, buflen);
2291 print_signal_handler(st, SR_signum, buf, buflen);
2292 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2293 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2294 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2295 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2296 #if defined(PPC64)
2297 print_signal_handler(st, SIGTRAP, buf, buflen);
2298 #endif
2299 }
2300
2301 static char saved_jvm_path[MAXPATHLEN] = {0};
2302
2303 // Find the full path to the current module, libjvm.so
2304 void os::jvm_path(char *buf, jint buflen) {
2305 // Error checking.
2306 if (buflen < MAXPATHLEN) {
2307 assert(false, "must use a large-enough buffer");
2308 buf[0] = '\0';
2309 return;
2310 }
2311 // Lazy resolve the path to current module.
2312 if (saved_jvm_path[0] != 0) {
2313 strcpy(buf, saved_jvm_path);
2314 return;
2315 }
2316
2317 char dli_fname[MAXPATHLEN];
2318 bool ret = dll_address_to_library_name(
2319 CAST_FROM_FN_PTR(address, os::jvm_path),
2320 dli_fname, sizeof(dli_fname), NULL);
2321 assert(ret, "cannot locate libjvm");
2322 char *rp = NULL;
2323 if (ret && dli_fname[0] != '\0') {
2324 rp = realpath(dli_fname, buf);
2325 }
2326 if (rp == NULL) {
2327 return;
2328 }
2329
2330 if (Arguments::sun_java_launcher_is_altjvm()) {
2331 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2332 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2333 // If "/jre/lib/" appears at the right place in the string, then
2334 // assume we are installed in a JDK and we're done. Otherwise, check
2335 // for a JAVA_HOME environment variable and fix up the path so it
2336 // looks like libjvm.so is installed there (append a fake suffix
2337 // hotspot/libjvm.so).
2338 const char *p = buf + strlen(buf) - 1;
2339 for (int count = 0; p > buf && count < 5; ++count) {
2340 for (--p; p > buf && *p != '/'; --p)
2341 /* empty */ ;
2342 }
2343
2344 if (strncmp(p, "/jre/lib/", 9) != 0) {
2345 // Look for JAVA_HOME in the environment.
2346 char* java_home_var = ::getenv("JAVA_HOME");
2347 if (java_home_var != NULL && java_home_var[0] != 0) {
2348 char* jrelib_p;
2349 int len;
2350
2351 // Check the current module name "libjvm.so".
2352 p = strrchr(buf, '/');
2353 if (p == NULL) {
2354 return;
2355 }
2356 assert(strstr(p, "/libjvm") == p, "invalid library name");
2357
2358 rp = realpath(java_home_var, buf);
2359 if (rp == NULL) {
2360 return;
2361 }
2362
2363 // determine if this is a legacy image or modules image
2364 // modules image doesn't have "jre" subdirectory
2365 len = strlen(buf);
2366 assert(len < buflen, "Ran out of buffer room");
2367 jrelib_p = buf + len;
2368 snprintf(jrelib_p, buflen-len, "/jre/lib");
2369 if (0 != access(buf, F_OK)) {
2370 snprintf(jrelib_p, buflen-len, "/lib");
2371 }
2372
2373 if (0 == access(buf, F_OK)) {
2374 // Use current module name "libjvm.so"
2375 len = strlen(buf);
2376 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2377 } else {
2378 // Go back to path of .so
2379 rp = realpath(dli_fname, buf);
2380 if (rp == NULL) {
2381 return;
2382 }
2383 }
2384 }
2385 }
2386 }
2387
2388 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2389 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2390 }
2391
2392 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2393 // no prefix required, not even "_"
2394 }
2395
2396 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2397 // no suffix required
2398 }
2399
2400 ////////////////////////////////////////////////////////////////////////////////
2401 // sun.misc.Signal support
2402
2403 static volatile jint sigint_count = 0;
2404
2405 static void UserHandler(int sig, void *siginfo, void *context) {
2406 // 4511530 - sem_post is serialized and handled by the manager thread. When
2407 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2408 // don't want to flood the manager thread with sem_post requests.
2409 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2410 return;
2411 }
2412
2413 // Ctrl-C is pressed during error reporting, likely because the error
2414 // handler fails to abort. Let VM die immediately.
2415 if (sig == SIGINT && is_error_reported()) {
2416 os::die();
2417 }
2418
2419 os::signal_notify(sig);
2420 }
2421
2422 void* os::user_handler() {
2423 return CAST_FROM_FN_PTR(void*, UserHandler);
2424 }
2425
2426 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2427 struct timespec ts;
2428 // Semaphore's are always associated with CLOCK_REALTIME
2429 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2430 // see unpackTime for discussion on overflow checking
2431 if (sec >= MAX_SECS) {
2432 ts.tv_sec += MAX_SECS;
2433 ts.tv_nsec = 0;
2434 } else {
2435 ts.tv_sec += sec;
2436 ts.tv_nsec += nsec;
2437 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2438 ts.tv_nsec -= NANOSECS_PER_SEC;
2439 ++ts.tv_sec; // note: this must be <= max_secs
2440 }
2441 }
2442
2443 return ts;
2444 }
2445
2446 extern "C" {
2447 typedef void (*sa_handler_t)(int);
2448 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2449 }
2450
2451 void* os::signal(int signal_number, void* handler) {
2452 struct sigaction sigAct, oldSigAct;
2453
2454 sigfillset(&(sigAct.sa_mask));
2455 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2456 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2457
2458 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2459 // -1 means registration failed
2460 return (void *)-1;
2461 }
2462
2463 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2464 }
2465
2466 void os::signal_raise(int signal_number) {
2467 ::raise(signal_number);
2468 }
2469
2470 // The following code is moved from os.cpp for making this
2471 // code platform specific, which it is by its very nature.
2472
2473 // Will be modified when max signal is changed to be dynamic
2474 int os::sigexitnum_pd() {
2475 return NSIG;
2476 }
2477
2478 // a counter for each possible signal value
2479 static volatile jint pending_signals[NSIG+1] = { 0 };
2480
2481 // Linux(POSIX) specific hand shaking semaphore.
2482 static sem_t sig_sem;
2483 static PosixSemaphore sr_semaphore;
2484
2485 void os::signal_init_pd() {
2486 // Initialize signal structures
2487 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2488
2489 // Initialize signal semaphore
2490 ::sem_init(&sig_sem, 0, 0);
2491 }
2492
2493 void os::signal_notify(int sig) {
2494 Atomic::inc(&pending_signals[sig]);
2495 ::sem_post(&sig_sem);
2496 }
2497
2498 static int check_pending_signals(bool wait) {
2499 Atomic::store(0, &sigint_count);
2500 for (;;) {
2501 for (int i = 0; i < NSIG + 1; i++) {
2502 jint n = pending_signals[i];
2503 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2504 return i;
2505 }
2506 }
2507 if (!wait) {
2508 return -1;
2509 }
2510 JavaThread *thread = JavaThread::current();
2511 ThreadBlockInVM tbivm(thread);
2512
2513 bool threadIsSuspended;
2514 do {
2515 thread->set_suspend_equivalent();
2516 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2517 ::sem_wait(&sig_sem);
2518
2519 // were we externally suspended while we were waiting?
2520 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2521 if (threadIsSuspended) {
2522 // The semaphore has been incremented, but while we were waiting
2523 // another thread suspended us. We don't want to continue running
2524 // while suspended because that would surprise the thread that
2525 // suspended us.
2526 ::sem_post(&sig_sem);
2527
2528 thread->java_suspend_self();
2529 }
2530 } while (threadIsSuspended);
2531 }
2532 }
2533
2534 int os::signal_lookup() {
2535 return check_pending_signals(false);
2536 }
2537
2538 int os::signal_wait() {
2539 return check_pending_signals(true);
2540 }
2541
2542 ////////////////////////////////////////////////////////////////////////////////
2543 // Virtual Memory
2544
2545 int os::vm_page_size() {
2546 // Seems redundant as all get out
2547 assert(os::Linux::page_size() != -1, "must call os::init");
2548 return os::Linux::page_size();
2549 }
2550
2551 // Solaris allocates memory by pages.
2552 int os::vm_allocation_granularity() {
2553 assert(os::Linux::page_size() != -1, "must call os::init");
2554 return os::Linux::page_size();
2555 }
2556
2557 // Rationale behind this function:
2558 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2559 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2560 // samples for JITted code. Here we create private executable mapping over the code cache
2561 // and then we can use standard (well, almost, as mapping can change) way to provide
2562 // info for the reporting script by storing timestamp and location of symbol
2563 void linux_wrap_code(char* base, size_t size) {
2564 static volatile jint cnt = 0;
2565
2566 if (!UseOprofile) {
2567 return;
2568 }
2569
2570 char buf[PATH_MAX+1];
2571 int num = Atomic::add(1, &cnt);
2572
2573 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2574 os::get_temp_directory(), os::current_process_id(), num);
2575 unlink(buf);
2576
2577 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2578
2579 if (fd != -1) {
2580 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2581 if (rv != (off_t)-1) {
2582 if (::write(fd, "", 1) == 1) {
2583 mmap(base, size,
2584 PROT_READ|PROT_WRITE|PROT_EXEC,
2585 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2586 }
2587 }
2588 ::close(fd);
2589 unlink(buf);
2590 }
2591 }
2592
2593 static bool recoverable_mmap_error(int err) {
2594 // See if the error is one we can let the caller handle. This
2595 // list of errno values comes from JBS-6843484. I can't find a
2596 // Linux man page that documents this specific set of errno
2597 // values so while this list currently matches Solaris, it may
2598 // change as we gain experience with this failure mode.
2599 switch (err) {
2600 case EBADF:
2601 case EINVAL:
2602 case ENOTSUP:
2603 // let the caller deal with these errors
2604 return true;
2605
2606 default:
2607 // Any remaining errors on this OS can cause our reserved mapping
2608 // to be lost. That can cause confusion where different data
2609 // structures think they have the same memory mapped. The worst
2610 // scenario is if both the VM and a library think they have the
2611 // same memory mapped.
2612 return false;
2613 }
2614 }
2615
2616 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2617 int err) {
2618 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2619 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2620 os::strerror(err), err);
2621 }
2622
2623 static void warn_fail_commit_memory(char* addr, size_t size,
2624 size_t alignment_hint, bool exec,
2625 int err) {
2626 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2627 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2628 alignment_hint, exec, os::strerror(err), err);
2629 }
2630
2631 // NOTE: Linux kernel does not really reserve the pages for us.
2632 // All it does is to check if there are enough free pages
2633 // left at the time of mmap(). This could be a potential
2634 // problem.
2635 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2636 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2637 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2638 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2639 if (res != (uintptr_t) MAP_FAILED) {
2640 if (UseNUMAInterleaving) {
2641 numa_make_global(addr, size);
2642 }
2643 return 0;
2644 }
2645
2646 int err = errno; // save errno from mmap() call above
2647
2648 if (!recoverable_mmap_error(err)) {
2649 warn_fail_commit_memory(addr, size, exec, err);
2650 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2651 }
2652
2653 return err;
2654 }
2655
2656 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2657 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2658 }
2659
2660 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2661 const char* mesg) {
2662 assert(mesg != NULL, "mesg must be specified");
2663 int err = os::Linux::commit_memory_impl(addr, size, exec);
2664 if (err != 0) {
2665 // the caller wants all commit errors to exit with the specified mesg:
2666 warn_fail_commit_memory(addr, size, exec, err);
2667 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2668 }
2669 }
2670
2671 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2672 #ifndef MAP_HUGETLB
2673 #define MAP_HUGETLB 0x40000
2674 #endif
2675
2676 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2677 #ifndef MADV_HUGEPAGE
2678 #define MADV_HUGEPAGE 14
2679 #endif
2680
2681 int os::Linux::commit_memory_impl(char* addr, size_t size,
2682 size_t alignment_hint, bool exec) {
2683 int err = os::Linux::commit_memory_impl(addr, size, exec);
2684 if (err == 0) {
2685 realign_memory(addr, size, alignment_hint);
2686 }
2687 return err;
2688 }
2689
2690 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2691 bool exec) {
2692 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2693 }
2694
2695 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2696 size_t alignment_hint, bool exec,
2697 const char* mesg) {
2698 assert(mesg != NULL, "mesg must be specified");
2699 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2700 if (err != 0) {
2701 // the caller wants all commit errors to exit with the specified mesg:
2702 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2703 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2704 }
2705 }
2706
2707 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2708 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2709 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2710 // be supported or the memory may already be backed by huge pages.
2711 ::madvise(addr, bytes, MADV_HUGEPAGE);
2712 }
2713 }
2714
2715 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2716 // This method works by doing an mmap over an existing mmaping and effectively discarding
2717 // the existing pages. However it won't work for SHM-based large pages that cannot be
2718 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2719 // small pages on top of the SHM segment. This method always works for small pages, so we
2720 // allow that in any case.
2721 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2722 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2723 }
2724 }
2725
2726 void os::numa_make_global(char *addr, size_t bytes) {
2727 Linux::numa_interleave_memory(addr, bytes);
2728 }
2729
2730 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2731 // bind policy to MPOL_PREFERRED for the current thread.
2732 #define USE_MPOL_PREFERRED 0
2733
2734 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2735 // To make NUMA and large pages more robust when both enabled, we need to ease
2736 // the requirements on where the memory should be allocated. MPOL_BIND is the
2737 // default policy and it will force memory to be allocated on the specified
2738 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2739 // the specified node, but will not force it. Using this policy will prevent
2740 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2741 // free large pages.
2742 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2743 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2744 }
2745
2746 bool os::numa_topology_changed() { return false; }
2747
2748 size_t os::numa_get_groups_num() {
2749 int max_node = Linux::numa_max_node();
2750 return max_node > 0 ? max_node + 1 : 1;
2751 }
2752
2753 int os::numa_get_group_id() {
2754 int cpu_id = Linux::sched_getcpu();
2755 if (cpu_id != -1) {
2756 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2757 if (lgrp_id != -1) {
2758 return lgrp_id;
2759 }
2760 }
2761 return 0;
2762 }
2763
2764 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2765 for (size_t i = 0; i < size; i++) {
2766 ids[i] = i;
2767 }
2768 return size;
2769 }
2770
2771 bool os::get_page_info(char *start, page_info* info) {
2772 return false;
2773 }
2774
2775 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2776 page_info* page_found) {
2777 return end;
2778 }
2779
2780
2781 int os::Linux::sched_getcpu_syscall(void) {
2782 unsigned int cpu = 0;
2783 int retval = -1;
2784
2785 #if defined(IA32)
2786 #ifndef SYS_getcpu
2787 #define SYS_getcpu 318
2788 #endif
2789 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2790 #elif defined(AMD64)
2791 // Unfortunately we have to bring all these macros here from vsyscall.h
2792 // to be able to compile on old linuxes.
2793 #define __NR_vgetcpu 2
2794 #define VSYSCALL_START (-10UL << 20)
2795 #define VSYSCALL_SIZE 1024
2796 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2797 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2798 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2799 retval = vgetcpu(&cpu, NULL, NULL);
2800 #endif
2801
2802 return (retval == -1) ? retval : cpu;
2803 }
2804
2805 // Something to do with the numa-aware allocator needs these symbols
2806 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2807 extern "C" JNIEXPORT void numa_error(char *where) { }
2808
2809
2810 // If we are running with libnuma version > 2, then we should
2811 // be trying to use symbols with versions 1.1
2812 // If we are running with earlier version, which did not have symbol versions,
2813 // we should use the base version.
2814 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2815 typedef void* (*dlvsym_func_type)(void* handle, const char* name, const char* version);
2816 static dlvsym_func_type dlvsym_func;
2817 static bool initialized = false;
2818
2819 if (!initialized) {
2820 dlvsym_func = (dlvsym_func_type)dlsym(RTLD_NEXT, "dlvsym");
2821 initialized = true;
2822 }
2823
2824 if (dlvsym_func != NULL) {
2825 void *f = dlvsym_func(handle, name, "libnuma_1.1");
2826 if (f != NULL) {
2827 return f;
2828 }
2829 }
2830
2831 return dlsym(handle, name);
2832 }
2833
2834 bool os::Linux::libnuma_init() {
2835 // sched_getcpu() should be in libc.
2836 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2837 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2838
2839 // If it's not, try a direct syscall.
2840 if (sched_getcpu() == -1) {
2841 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2842 (void*)&sched_getcpu_syscall));
2843 }
2844
2845 if (sched_getcpu() != -1) { // Does it work?
2846 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2847 if (handle != NULL) {
2848 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2849 libnuma_dlsym(handle, "numa_node_to_cpus")));
2850 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2851 libnuma_dlsym(handle, "numa_max_node")));
2852 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2853 libnuma_dlsym(handle, "numa_available")));
2854 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2855 libnuma_dlsym(handle, "numa_tonode_memory")));
2856 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2857 libnuma_dlsym(handle, "numa_interleave_memory")));
2858 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2859 libnuma_dlsym(handle, "numa_set_bind_policy")));
2860
2861
2862 if (numa_available() != -1) {
2863 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2864 // Create a cpu -> node mapping
2865 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2866 rebuild_cpu_to_node_map();
2867 return true;
2868 }
2869 }
2870 }
2871 return false;
2872 }
2873
2874 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
2875 // Creating guard page is very expensive. Java thread has HotSpot
2876 // guard pages, only enable glibc guard page for non-Java threads.
2877 // (Remember: compiler thread is a Java thread, too!)
2878 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
2879 }
2880
2881 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2882 // The table is later used in get_node_by_cpu().
2883 void os::Linux::rebuild_cpu_to_node_map() {
2884 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2885 // in libnuma (possible values are starting from 16,
2886 // and continuing up with every other power of 2, but less
2887 // than the maximum number of CPUs supported by kernel), and
2888 // is a subject to change (in libnuma version 2 the requirements
2889 // are more reasonable) we'll just hardcode the number they use
2890 // in the library.
2891 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2892
2893 size_t cpu_num = processor_count();
2894 size_t cpu_map_size = NCPUS / BitsPerCLong;
2895 size_t cpu_map_valid_size =
2896 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2897
2898 cpu_to_node()->clear();
2899 cpu_to_node()->at_grow(cpu_num - 1);
2900 size_t node_num = numa_get_groups_num();
2901
2902 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2903 for (size_t i = 0; i < node_num; i++) {
2904 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2905 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2906 if (cpu_map[j] != 0) {
2907 for (size_t k = 0; k < BitsPerCLong; k++) {
2908 if (cpu_map[j] & (1UL << k)) {
2909 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2910 }
2911 }
2912 }
2913 }
2914 }
2915 }
2916 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2917 }
2918
2919 int os::Linux::get_node_by_cpu(int cpu_id) {
2920 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2921 return cpu_to_node()->at(cpu_id);
2922 }
2923 return -1;
2924 }
2925
2926 GrowableArray<int>* os::Linux::_cpu_to_node;
2927 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2928 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2929 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2930 os::Linux::numa_available_func_t os::Linux::_numa_available;
2931 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2932 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2933 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2934 unsigned long* os::Linux::_numa_all_nodes;
2935
2936 bool os::pd_uncommit_memory(char* addr, size_t size) {
2937 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2938 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2939 return res != (uintptr_t) MAP_FAILED;
2940 }
2941
2942 static address get_stack_commited_bottom(address bottom, size_t size) {
2943 address nbot = bottom;
2944 address ntop = bottom + size;
2945
2946 size_t page_sz = os::vm_page_size();
2947 unsigned pages = size / page_sz;
2948
2949 unsigned char vec[1];
2950 unsigned imin = 1, imax = pages + 1, imid;
2951 int mincore_return_value = 0;
2952
2953 assert(imin <= imax, "Unexpected page size");
2954
2955 while (imin < imax) {
2956 imid = (imax + imin) / 2;
2957 nbot = ntop - (imid * page_sz);
2958
2959 // Use a trick with mincore to check whether the page is mapped or not.
2960 // mincore sets vec to 1 if page resides in memory and to 0 if page
2961 // is swapped output but if page we are asking for is unmapped
2962 // it returns -1,ENOMEM
2963 mincore_return_value = mincore(nbot, page_sz, vec);
2964
2965 if (mincore_return_value == -1) {
2966 // Page is not mapped go up
2967 // to find first mapped page
2968 if (errno != EAGAIN) {
2969 assert(errno == ENOMEM, "Unexpected mincore errno");
2970 imax = imid;
2971 }
2972 } else {
2973 // Page is mapped go down
2974 // to find first not mapped page
2975 imin = imid + 1;
2976 }
2977 }
2978
2979 nbot = nbot + page_sz;
2980
2981 // Adjust stack bottom one page up if last checked page is not mapped
2982 if (mincore_return_value == -1) {
2983 nbot = nbot + page_sz;
2984 }
2985
2986 return nbot;
2987 }
2988
2989
2990 // Linux uses a growable mapping for the stack, and if the mapping for
2991 // the stack guard pages is not removed when we detach a thread the
2992 // stack cannot grow beyond the pages where the stack guard was
2993 // mapped. If at some point later in the process the stack expands to
2994 // that point, the Linux kernel cannot expand the stack any further
2995 // because the guard pages are in the way, and a segfault occurs.
2996 //
2997 // However, it's essential not to split the stack region by unmapping
2998 // a region (leaving a hole) that's already part of the stack mapping,
2999 // so if the stack mapping has already grown beyond the guard pages at
3000 // the time we create them, we have to truncate the stack mapping.
3001 // So, we need to know the extent of the stack mapping when
3002 // create_stack_guard_pages() is called.
3003
3004 // We only need this for stacks that are growable: at the time of
3005 // writing thread stacks don't use growable mappings (i.e. those
3006 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3007 // only applies to the main thread.
3008
3009 // If the (growable) stack mapping already extends beyond the point
3010 // where we're going to put our guard pages, truncate the mapping at
3011 // that point by munmap()ping it. This ensures that when we later
3012 // munmap() the guard pages we don't leave a hole in the stack
3013 // mapping. This only affects the main/initial thread
3014
3015 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3016 if (os::Linux::is_initial_thread()) {
3017 // As we manually grow stack up to bottom inside create_attached_thread(),
3018 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3019 // we don't need to do anything special.
3020 // Check it first, before calling heavy function.
3021 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3022 unsigned char vec[1];
3023
3024 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3025 // Fallback to slow path on all errors, including EAGAIN
3026 stack_extent = (uintptr_t) get_stack_commited_bottom(
3027 os::Linux::initial_thread_stack_bottom(),
3028 (size_t)addr - stack_extent);
3029 }
3030
3031 if (stack_extent < (uintptr_t)addr) {
3032 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3033 }
3034 }
3035
3036 return os::commit_memory(addr, size, !ExecMem);
3037 }
3038
3039 // If this is a growable mapping, remove the guard pages entirely by
3040 // munmap()ping them. If not, just call uncommit_memory(). This only
3041 // affects the main/initial thread, but guard against future OS changes
3042 // It's safe to always unmap guard pages for initial thread because we
3043 // always place it right after end of the mapped region
3044
3045 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3046 uintptr_t stack_extent, stack_base;
3047
3048 if (os::Linux::is_initial_thread()) {
3049 return ::munmap(addr, size) == 0;
3050 }
3051
3052 return os::uncommit_memory(addr, size);
3053 }
3054
3055 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3056 // at 'requested_addr'. If there are existing memory mappings at the same
3057 // location, however, they will be overwritten. If 'fixed' is false,
3058 // 'requested_addr' is only treated as a hint, the return value may or
3059 // may not start from the requested address. Unlike Linux mmap(), this
3060 // function returns NULL to indicate failure.
3061 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3062 char * addr;
3063 int flags;
3064
3065 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3066 if (fixed) {
3067 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3068 flags |= MAP_FIXED;
3069 }
3070
3071 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3072 // touch an uncommitted page. Otherwise, the read/write might
3073 // succeed if we have enough swap space to back the physical page.
3074 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3075 flags, -1, 0);
3076
3077 return addr == MAP_FAILED ? NULL : addr;
3078 }
3079
3080 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3081 // (req_addr != NULL) or with a given alignment.
3082 // - bytes shall be a multiple of alignment.
3083 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3084 // - alignment sets the alignment at which memory shall be allocated.
3085 // It must be a multiple of allocation granularity.
3086 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3087 // req_addr or NULL.
3088 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3089
3090 size_t extra_size = bytes;
3091 if (req_addr == NULL && alignment > 0) {
3092 extra_size += alignment;
3093 }
3094
3095 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3096 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3097 -1, 0);
3098 if (start == MAP_FAILED) {
3099 start = NULL;
3100 } else {
3101 if (req_addr != NULL) {
3102 if (start != req_addr) {
3103 ::munmap(start, extra_size);
3104 start = NULL;
3105 }
3106 } else {
3107 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3108 char* const end_aligned = start_aligned + bytes;
3109 char* const end = start + extra_size;
3110 if (start_aligned > start) {
3111 ::munmap(start, start_aligned - start);
3112 }
3113 if (end_aligned < end) {
3114 ::munmap(end_aligned, end - end_aligned);
3115 }
3116 start = start_aligned;
3117 }
3118 }
3119 return start;
3120 }
3121
3122 static int anon_munmap(char * addr, size_t size) {
3123 return ::munmap(addr, size) == 0;
3124 }
3125
3126 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3127 size_t alignment_hint) {
3128 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3129 }
3130
3131 bool os::pd_release_memory(char* addr, size_t size) {
3132 return anon_munmap(addr, size);
3133 }
3134
3135 static bool linux_mprotect(char* addr, size_t size, int prot) {
3136 // Linux wants the mprotect address argument to be page aligned.
3137 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3138
3139 // According to SUSv3, mprotect() should only be used with mappings
3140 // established by mmap(), and mmap() always maps whole pages. Unaligned
3141 // 'addr' likely indicates problem in the VM (e.g. trying to change
3142 // protection of malloc'ed or statically allocated memory). Check the
3143 // caller if you hit this assert.
3144 assert(addr == bottom, "sanity check");
3145
3146 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3147 return ::mprotect(bottom, size, prot) == 0;
3148 }
3149
3150 // Set protections specified
3151 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3152 bool is_committed) {
3153 unsigned int p = 0;
3154 switch (prot) {
3155 case MEM_PROT_NONE: p = PROT_NONE; break;
3156 case MEM_PROT_READ: p = PROT_READ; break;
3157 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3158 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3159 default:
3160 ShouldNotReachHere();
3161 }
3162 // is_committed is unused.
3163 return linux_mprotect(addr, bytes, p);
3164 }
3165
3166 bool os::guard_memory(char* addr, size_t size) {
3167 return linux_mprotect(addr, size, PROT_NONE);
3168 }
3169
3170 bool os::unguard_memory(char* addr, size_t size) {
3171 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3172 }
3173
3174 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3175 size_t page_size) {
3176 bool result = false;
3177 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3178 MAP_ANONYMOUS|MAP_PRIVATE,
3179 -1, 0);
3180 if (p != MAP_FAILED) {
3181 void *aligned_p = align_ptr_up(p, page_size);
3182
3183 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3184
3185 munmap(p, page_size * 2);
3186 }
3187
3188 if (warn && !result) {
3189 warning("TransparentHugePages is not supported by the operating system.");
3190 }
3191
3192 return result;
3193 }
3194
3195 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3196 bool result = false;
3197 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3198 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3199 -1, 0);
3200
3201 if (p != MAP_FAILED) {
3202 // We don't know if this really is a huge page or not.
3203 FILE *fp = fopen("/proc/self/maps", "r");
3204 if (fp) {
3205 while (!feof(fp)) {
3206 char chars[257];
3207 long x = 0;
3208 if (fgets(chars, sizeof(chars), fp)) {
3209 if (sscanf(chars, "%lx-%*x", &x) == 1
3210 && x == (long)p) {
3211 if (strstr (chars, "hugepage")) {
3212 result = true;
3213 break;
3214 }
3215 }
3216 }
3217 }
3218 fclose(fp);
3219 }
3220 munmap(p, page_size);
3221 }
3222
3223 if (warn && !result) {
3224 warning("HugeTLBFS is not supported by the operating system.");
3225 }
3226
3227 return result;
3228 }
3229
3230 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3231 //
3232 // From the coredump_filter documentation:
3233 //
3234 // - (bit 0) anonymous private memory
3235 // - (bit 1) anonymous shared memory
3236 // - (bit 2) file-backed private memory
3237 // - (bit 3) file-backed shared memory
3238 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3239 // effective only if the bit 2 is cleared)
3240 // - (bit 5) hugetlb private memory
3241 // - (bit 6) hugetlb shared memory
3242 //
3243 static void set_coredump_filter(void) {
3244 FILE *f;
3245 long cdm;
3246
3247 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3248 return;
3249 }
3250
3251 if (fscanf(f, "%lx", &cdm) != 1) {
3252 fclose(f);
3253 return;
3254 }
3255
3256 rewind(f);
3257
3258 if ((cdm & LARGEPAGES_BIT) == 0) {
3259 cdm |= LARGEPAGES_BIT;
3260 fprintf(f, "%#lx", cdm);
3261 }
3262
3263 fclose(f);
3264 }
3265
3266 // Large page support
3267
3268 static size_t _large_page_size = 0;
3269
3270 size_t os::Linux::find_large_page_size() {
3271 size_t large_page_size = 0;
3272
3273 // large_page_size on Linux is used to round up heap size. x86 uses either
3274 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3275 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3276 // page as large as 256M.
3277 //
3278 // Here we try to figure out page size by parsing /proc/meminfo and looking
3279 // for a line with the following format:
3280 // Hugepagesize: 2048 kB
3281 //
3282 // If we can't determine the value (e.g. /proc is not mounted, or the text
3283 // format has been changed), we'll use the largest page size supported by
3284 // the processor.
3285
3286 #ifndef ZERO
3287 large_page_size =
3288 AARCH64_ONLY(2 * M)
3289 AMD64_ONLY(2 * M)
3290 ARM32_ONLY(2 * M)
3291 IA32_ONLY(4 * M)
3292 IA64_ONLY(256 * M)
3293 PPC_ONLY(4 * M)
3294 S390_ONLY(1 * M)
3295 SPARC_ONLY(4 * M);
3296 #endif // ZERO
3297
3298 FILE *fp = fopen("/proc/meminfo", "r");
3299 if (fp) {
3300 while (!feof(fp)) {
3301 int x = 0;
3302 char buf[16];
3303 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3304 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3305 large_page_size = x * K;
3306 break;
3307 }
3308 } else {
3309 // skip to next line
3310 for (;;) {
3311 int ch = fgetc(fp);
3312 if (ch == EOF || ch == (int)'\n') break;
3313 }
3314 }
3315 }
3316 fclose(fp);
3317 }
3318
3319 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3320 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3321 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3322 proper_unit_for_byte_size(large_page_size));
3323 }
3324
3325 return large_page_size;
3326 }
3327
3328 size_t os::Linux::setup_large_page_size() {
3329 _large_page_size = Linux::find_large_page_size();
3330 const size_t default_page_size = (size_t)Linux::page_size();
3331 if (_large_page_size > default_page_size) {
3332 _page_sizes[0] = _large_page_size;
3333 _page_sizes[1] = default_page_size;
3334 _page_sizes[2] = 0;
3335 }
3336
3337 return _large_page_size;
3338 }
3339
3340 bool os::Linux::setup_large_page_type(size_t page_size) {
3341 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3342 FLAG_IS_DEFAULT(UseSHM) &&
3343 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3344
3345 // The type of large pages has not been specified by the user.
3346
3347 // Try UseHugeTLBFS and then UseSHM.
3348 UseHugeTLBFS = UseSHM = true;
3349
3350 // Don't try UseTransparentHugePages since there are known
3351 // performance issues with it turned on. This might change in the future.
3352 UseTransparentHugePages = false;
3353 }
3354
3355 if (UseTransparentHugePages) {
3356 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3357 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3358 UseHugeTLBFS = false;
3359 UseSHM = false;
3360 return true;
3361 }
3362 UseTransparentHugePages = false;
3363 }
3364
3365 if (UseHugeTLBFS) {
3366 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3367 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3368 UseSHM = false;
3369 return true;
3370 }
3371 UseHugeTLBFS = false;
3372 }
3373
3374 return UseSHM;
3375 }
3376
3377 void os::large_page_init() {
3378 if (!UseLargePages &&
3379 !UseTransparentHugePages &&
3380 !UseHugeTLBFS &&
3381 !UseSHM) {
3382 // Not using large pages.
3383 return;
3384 }
3385
3386 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3387 // The user explicitly turned off large pages.
3388 // Ignore the rest of the large pages flags.
3389 UseTransparentHugePages = false;
3390 UseHugeTLBFS = false;
3391 UseSHM = false;
3392 return;
3393 }
3394
3395 size_t large_page_size = Linux::setup_large_page_size();
3396 UseLargePages = Linux::setup_large_page_type(large_page_size);
3397
3398 set_coredump_filter();
3399 }
3400
3401 #ifndef SHM_HUGETLB
3402 #define SHM_HUGETLB 04000
3403 #endif
3404
3405 #define shm_warning_format(format, ...) \
3406 do { \
3407 if (UseLargePages && \
3408 (!FLAG_IS_DEFAULT(UseLargePages) || \
3409 !FLAG_IS_DEFAULT(UseSHM) || \
3410 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3411 warning(format, __VA_ARGS__); \
3412 } \
3413 } while (0)
3414
3415 #define shm_warning(str) shm_warning_format("%s", str)
3416
3417 #define shm_warning_with_errno(str) \
3418 do { \
3419 int err = errno; \
3420 shm_warning_format(str " (error = %d)", err); \
3421 } while (0)
3422
3423 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3424 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3425
3426 if (!is_size_aligned(alignment, SHMLBA)) {
3427 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3428 return NULL;
3429 }
3430
3431 // To ensure that we get 'alignment' aligned memory from shmat,
3432 // we pre-reserve aligned virtual memory and then attach to that.
3433
3434 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3435 if (pre_reserved_addr == NULL) {
3436 // Couldn't pre-reserve aligned memory.
3437 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3438 return NULL;
3439 }
3440
3441 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3442 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3443
3444 if ((intptr_t)addr == -1) {
3445 int err = errno;
3446 shm_warning_with_errno("Failed to attach shared memory.");
3447
3448 assert(err != EACCES, "Unexpected error");
3449 assert(err != EIDRM, "Unexpected error");
3450 assert(err != EINVAL, "Unexpected error");
3451
3452 // Since we don't know if the kernel unmapped the pre-reserved memory area
3453 // we can't unmap it, since that would potentially unmap memory that was
3454 // mapped from other threads.
3455 return NULL;
3456 }
3457
3458 return addr;
3459 }
3460
3461 static char* shmat_at_address(int shmid, char* req_addr) {
3462 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3463 assert(false, "Requested address needs to be SHMLBA aligned");
3464 return NULL;
3465 }
3466
3467 char* addr = (char*)shmat(shmid, req_addr, 0);
3468
3469 if ((intptr_t)addr == -1) {
3470 shm_warning_with_errno("Failed to attach shared memory.");
3471 return NULL;
3472 }
3473
3474 return addr;
3475 }
3476
3477 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3478 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3479 if (req_addr != NULL) {
3480 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3481 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3482 return shmat_at_address(shmid, req_addr);
3483 }
3484
3485 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3486 // return large page size aligned memory addresses when req_addr == NULL.
3487 // However, if the alignment is larger than the large page size, we have
3488 // to manually ensure that the memory returned is 'alignment' aligned.
3489 if (alignment > os::large_page_size()) {
3490 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3491 return shmat_with_alignment(shmid, bytes, alignment);
3492 } else {
3493 return shmat_at_address(shmid, NULL);
3494 }
3495 }
3496
3497 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3498 char* req_addr, bool exec) {
3499 // "exec" is passed in but not used. Creating the shared image for
3500 // the code cache doesn't have an SHM_X executable permission to check.
3501 assert(UseLargePages && UseSHM, "only for SHM large pages");
3502 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3503 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3504
3505 if (!is_size_aligned(bytes, os::large_page_size())) {
3506 return NULL; // Fallback to small pages.
3507 }
3508
3509 // Create a large shared memory region to attach to based on size.
3510 // Currently, size is the total size of the heap.
3511 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3512 if (shmid == -1) {
3513 // Possible reasons for shmget failure:
3514 // 1. shmmax is too small for Java heap.
3515 // > check shmmax value: cat /proc/sys/kernel/shmmax
3516 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3517 // 2. not enough large page memory.
3518 // > check available large pages: cat /proc/meminfo
3519 // > increase amount of large pages:
3520 // echo new_value > /proc/sys/vm/nr_hugepages
3521 // Note 1: different Linux may use different name for this property,
3522 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3523 // Note 2: it's possible there's enough physical memory available but
3524 // they are so fragmented after a long run that they can't
3525 // coalesce into large pages. Try to reserve large pages when
3526 // the system is still "fresh".
3527 shm_warning_with_errno("Failed to reserve shared memory.");
3528 return NULL;
3529 }
3530
3531 // Attach to the region.
3532 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3533
3534 // Remove shmid. If shmat() is successful, the actual shared memory segment
3535 // will be deleted when it's detached by shmdt() or when the process
3536 // terminates. If shmat() is not successful this will remove the shared
3537 // segment immediately.
3538 shmctl(shmid, IPC_RMID, NULL);
3539
3540 return addr;
3541 }
3542
3543 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3544 int error) {
3545 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3546
3547 bool warn_on_failure = UseLargePages &&
3548 (!FLAG_IS_DEFAULT(UseLargePages) ||
3549 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3550 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3551
3552 if (warn_on_failure) {
3553 char msg[128];
3554 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3555 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3556 warning("%s", msg);
3557 }
3558 }
3559
3560 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3561 char* req_addr,
3562 bool exec) {
3563 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3564 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3565 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3566
3567 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3568 char* addr = (char*)::mmap(req_addr, bytes, prot,
3569 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3570 -1, 0);
3571
3572 if (addr == MAP_FAILED) {
3573 warn_on_large_pages_failure(req_addr, bytes, errno);
3574 return NULL;
3575 }
3576
3577 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3578
3579 return addr;
3580 }
3581
3582 // Reserve memory using mmap(MAP_HUGETLB).
3583 // - bytes shall be a multiple of alignment.
3584 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3585 // - alignment sets the alignment at which memory shall be allocated.
3586 // It must be a multiple of allocation granularity.
3587 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3588 // req_addr or NULL.
3589 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3590 size_t alignment,
3591 char* req_addr,
3592 bool exec) {
3593 size_t large_page_size = os::large_page_size();
3594 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3595
3596 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3597 assert(is_size_aligned(bytes, alignment), "Must be");
3598
3599 // First reserve - but not commit - the address range in small pages.
3600 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3601
3602 if (start == NULL) {
3603 return NULL;
3604 }
3605
3606 assert(is_ptr_aligned(start, alignment), "Must be");
3607
3608 char* end = start + bytes;
3609
3610 // Find the regions of the allocated chunk that can be promoted to large pages.
3611 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3612 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3613
3614 size_t lp_bytes = lp_end - lp_start;
3615
3616 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3617
3618 if (lp_bytes == 0) {
3619 // The mapped region doesn't even span the start and the end of a large page.
3620 // Fall back to allocate a non-special area.
3621 ::munmap(start, end - start);
3622 return NULL;
3623 }
3624
3625 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3626
3627 void* result;
3628
3629 // Commit small-paged leading area.
3630 if (start != lp_start) {
3631 result = ::mmap(start, lp_start - start, prot,
3632 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3633 -1, 0);
3634 if (result == MAP_FAILED) {
3635 ::munmap(lp_start, end - lp_start);
3636 return NULL;
3637 }
3638 }
3639
3640 // Commit large-paged area.
3641 result = ::mmap(lp_start, lp_bytes, prot,
3642 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3643 -1, 0);
3644 if (result == MAP_FAILED) {
3645 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3646 // If the mmap above fails, the large pages region will be unmapped and we
3647 // have regions before and after with small pages. Release these regions.
3648 //
3649 // | mapped | unmapped | mapped |
3650 // ^ ^ ^ ^
3651 // start lp_start lp_end end
3652 //
3653 ::munmap(start, lp_start - start);
3654 ::munmap(lp_end, end - lp_end);
3655 return NULL;
3656 }
3657
3658 // Commit small-paged trailing area.
3659 if (lp_end != end) {
3660 result = ::mmap(lp_end, end - lp_end, prot,
3661 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3662 -1, 0);
3663 if (result == MAP_FAILED) {
3664 ::munmap(start, lp_end - start);
3665 return NULL;
3666 }
3667 }
3668
3669 return start;
3670 }
3671
3672 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3673 size_t alignment,
3674 char* req_addr,
3675 bool exec) {
3676 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3677 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3678 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3679 assert(is_power_of_2(os::large_page_size()), "Must be");
3680 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3681
3682 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3683 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3684 } else {
3685 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3686 }
3687 }
3688
3689 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3690 char* req_addr, bool exec) {
3691 assert(UseLargePages, "only for large pages");
3692
3693 char* addr;
3694 if (UseSHM) {
3695 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3696 } else {
3697 assert(UseHugeTLBFS, "must be");
3698 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3699 }
3700
3701 if (addr != NULL) {
3702 if (UseNUMAInterleaving) {
3703 numa_make_global(addr, bytes);
3704 }
3705
3706 // The memory is committed
3707 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3708 }
3709
3710 return addr;
3711 }
3712
3713 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3714 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3715 return shmdt(base) == 0;
3716 }
3717
3718 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3719 return pd_release_memory(base, bytes);
3720 }
3721
3722 bool os::release_memory_special(char* base, size_t bytes) {
3723 bool res;
3724 if (MemTracker::tracking_level() > NMT_minimal) {
3725 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3726 res = os::Linux::release_memory_special_impl(base, bytes);
3727 if (res) {
3728 tkr.record((address)base, bytes);
3729 }
3730
3731 } else {
3732 res = os::Linux::release_memory_special_impl(base, bytes);
3733 }
3734 return res;
3735 }
3736
3737 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3738 assert(UseLargePages, "only for large pages");
3739 bool res;
3740
3741 if (UseSHM) {
3742 res = os::Linux::release_memory_special_shm(base, bytes);
3743 } else {
3744 assert(UseHugeTLBFS, "must be");
3745 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3746 }
3747 return res;
3748 }
3749
3750 size_t os::large_page_size() {
3751 return _large_page_size;
3752 }
3753
3754 // With SysV SHM the entire memory region must be allocated as shared
3755 // memory.
3756 // HugeTLBFS allows application to commit large page memory on demand.
3757 // However, when committing memory with HugeTLBFS fails, the region
3758 // that was supposed to be committed will lose the old reservation
3759 // and allow other threads to steal that memory region. Because of this
3760 // behavior we can't commit HugeTLBFS memory.
3761 bool os::can_commit_large_page_memory() {
3762 return UseTransparentHugePages;
3763 }
3764
3765 bool os::can_execute_large_page_memory() {
3766 return UseTransparentHugePages || UseHugeTLBFS;
3767 }
3768
3769 // Reserve memory at an arbitrary address, only if that area is
3770 // available (and not reserved for something else).
3771
3772 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3773 const int max_tries = 10;
3774 char* base[max_tries];
3775 size_t size[max_tries];
3776 const size_t gap = 0x000000;
3777
3778 // Assert only that the size is a multiple of the page size, since
3779 // that's all that mmap requires, and since that's all we really know
3780 // about at this low abstraction level. If we need higher alignment,
3781 // we can either pass an alignment to this method or verify alignment
3782 // in one of the methods further up the call chain. See bug 5044738.
3783 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3784
3785 // Repeatedly allocate blocks until the block is allocated at the
3786 // right spot.
3787
3788 // Linux mmap allows caller to pass an address as hint; give it a try first,
3789 // if kernel honors the hint then we can return immediately.
3790 char * addr = anon_mmap(requested_addr, bytes, false);
3791 if (addr == requested_addr) {
3792 return requested_addr;
3793 }
3794
3795 if (addr != NULL) {
3796 // mmap() is successful but it fails to reserve at the requested address
3797 anon_munmap(addr, bytes);
3798 }
3799
3800 int i;
3801 for (i = 0; i < max_tries; ++i) {
3802 base[i] = reserve_memory(bytes);
3803
3804 if (base[i] != NULL) {
3805 // Is this the block we wanted?
3806 if (base[i] == requested_addr) {
3807 size[i] = bytes;
3808 break;
3809 }
3810
3811 // Does this overlap the block we wanted? Give back the overlapped
3812 // parts and try again.
3813
3814 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3815 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3816 unmap_memory(base[i], top_overlap);
3817 base[i] += top_overlap;
3818 size[i] = bytes - top_overlap;
3819 } else {
3820 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3821 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3822 unmap_memory(requested_addr, bottom_overlap);
3823 size[i] = bytes - bottom_overlap;
3824 } else {
3825 size[i] = bytes;
3826 }
3827 }
3828 }
3829 }
3830
3831 // Give back the unused reserved pieces.
3832
3833 for (int j = 0; j < i; ++j) {
3834 if (base[j] != NULL) {
3835 unmap_memory(base[j], size[j]);
3836 }
3837 }
3838
3839 if (i < max_tries) {
3840 return requested_addr;
3841 } else {
3842 return NULL;
3843 }
3844 }
3845
3846 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3847 return ::read(fd, buf, nBytes);
3848 }
3849
3850 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3851 return ::pread(fd, buf, nBytes, offset);
3852 }
3853
3854 // Short sleep, direct OS call.
3855 //
3856 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3857 // sched_yield(2) will actually give up the CPU:
3858 //
3859 // * Alone on this pariticular CPU, keeps running.
3860 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3861 // (pre 2.6.39).
3862 //
3863 // So calling this with 0 is an alternative.
3864 //
3865 void os::naked_short_sleep(jlong ms) {
3866 struct timespec req;
3867
3868 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3869 req.tv_sec = 0;
3870 if (ms > 0) {
3871 req.tv_nsec = (ms % 1000) * 1000000;
3872 } else {
3873 req.tv_nsec = 1;
3874 }
3875
3876 nanosleep(&req, NULL);
3877
3878 return;
3879 }
3880
3881 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3882 void os::infinite_sleep() {
3883 while (true) { // sleep forever ...
3884 ::sleep(100); // ... 100 seconds at a time
3885 }
3886 }
3887
3888 // Used to convert frequent JVM_Yield() to nops
3889 bool os::dont_yield() {
3890 return DontYieldALot;
3891 }
3892
3893 void os::naked_yield() {
3894 sched_yield();
3895 }
3896
3897 ////////////////////////////////////////////////////////////////////////////////
3898 // thread priority support
3899
3900 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3901 // only supports dynamic priority, static priority must be zero. For real-time
3902 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3903 // However, for large multi-threaded applications, SCHED_RR is not only slower
3904 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3905 // of 5 runs - Sep 2005).
3906 //
3907 // The following code actually changes the niceness of kernel-thread/LWP. It
3908 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3909 // not the entire user process, and user level threads are 1:1 mapped to kernel
3910 // threads. It has always been the case, but could change in the future. For
3911 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3912 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3913
3914 int os::java_to_os_priority[CriticalPriority + 1] = {
3915 19, // 0 Entry should never be used
3916
3917 4, // 1 MinPriority
3918 3, // 2
3919 2, // 3
3920
3921 1, // 4
3922 0, // 5 NormPriority
3923 -1, // 6
3924
3925 -2, // 7
3926 -3, // 8
3927 -4, // 9 NearMaxPriority
3928
3929 -5, // 10 MaxPriority
3930
3931 -5 // 11 CriticalPriority
3932 };
3933
3934 static int prio_init() {
3935 if (ThreadPriorityPolicy == 1) {
3936 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3937 // if effective uid is not root. Perhaps, a more elegant way of doing
3938 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3939 if (geteuid() != 0) {
3940 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3941 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3942 }
3943 ThreadPriorityPolicy = 0;
3944 }
3945 }
3946 if (UseCriticalJavaThreadPriority) {
3947 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3948 }
3949 return 0;
3950 }
3951
3952 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3953 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3954
3955 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3956 return (ret == 0) ? OS_OK : OS_ERR;
3957 }
3958
3959 OSReturn os::get_native_priority(const Thread* const thread,
3960 int *priority_ptr) {
3961 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3962 *priority_ptr = java_to_os_priority[NormPriority];
3963 return OS_OK;
3964 }
3965
3966 errno = 0;
3967 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3968 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3969 }
3970
3971 // Hint to the underlying OS that a task switch would not be good.
3972 // Void return because it's a hint and can fail.
3973 void os::hint_no_preempt() {}
3974
3975 ////////////////////////////////////////////////////////////////////////////////
3976 // suspend/resume support
3977
3978 // the low-level signal-based suspend/resume support is a remnant from the
3979 // old VM-suspension that used to be for java-suspension, safepoints etc,
3980 // within hotspot. Now there is a single use-case for this:
3981 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3982 // that runs in the watcher thread.
3983 // The remaining code is greatly simplified from the more general suspension
3984 // code that used to be used.
3985 //
3986 // The protocol is quite simple:
3987 // - suspend:
3988 // - sends a signal to the target thread
3989 // - polls the suspend state of the osthread using a yield loop
3990 // - target thread signal handler (SR_handler) sets suspend state
3991 // and blocks in sigsuspend until continued
3992 // - resume:
3993 // - sets target osthread state to continue
3994 // - sends signal to end the sigsuspend loop in the SR_handler
3995 //
3996 // Note that the SR_lock plays no role in this suspend/resume protocol,
3997 // but is checked for NULL in SR_handler as a thread termination indicator.
3998
3999 static void resume_clear_context(OSThread *osthread) {
4000 osthread->set_ucontext(NULL);
4001 osthread->set_siginfo(NULL);
4002 }
4003
4004 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
4005 ucontext_t* context) {
4006 osthread->set_ucontext(context);
4007 osthread->set_siginfo(siginfo);
4008 }
4009
4010 // Handler function invoked when a thread's execution is suspended or
4011 // resumed. We have to be careful that only async-safe functions are
4012 // called here (Note: most pthread functions are not async safe and
4013 // should be avoided.)
4014 //
4015 // Note: sigwait() is a more natural fit than sigsuspend() from an
4016 // interface point of view, but sigwait() prevents the signal hander
4017 // from being run. libpthread would get very confused by not having
4018 // its signal handlers run and prevents sigwait()'s use with the
4019 // mutex granting granting signal.
4020 //
4021 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4022 //
4023 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4024 // Save and restore errno to avoid confusing native code with EINTR
4025 // after sigsuspend.
4026 int old_errno = errno;
4027
4028 Thread* thread = Thread::current_or_null_safe();
4029 assert(thread != NULL, "Missing current thread in SR_handler");
4030
4031 // On some systems we have seen signal delivery get "stuck" until the signal
4032 // mask is changed as part of thread termination. Check that the current thread
4033 // has not already terminated (via SR_lock()) - else the following assertion
4034 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4035 // destructor has completed.
4036
4037 if (thread->SR_lock() == NULL) {
4038 return;
4039 }
4040
4041 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4042
4043 OSThread* osthread = thread->osthread();
4044
4045 os::SuspendResume::State current = osthread->sr.state();
4046 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4047 suspend_save_context(osthread, siginfo, context);
4048
4049 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4050 os::SuspendResume::State state = osthread->sr.suspended();
4051 if (state == os::SuspendResume::SR_SUSPENDED) {
4052 sigset_t suspend_set; // signals for sigsuspend()
4053 sigemptyset(&suspend_set);
4054 // get current set of blocked signals and unblock resume signal
4055 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4056 sigdelset(&suspend_set, SR_signum);
4057
4058 sr_semaphore.signal();
4059 // wait here until we are resumed
4060 while (1) {
4061 sigsuspend(&suspend_set);
4062
4063 os::SuspendResume::State result = osthread->sr.running();
4064 if (result == os::SuspendResume::SR_RUNNING) {
4065 sr_semaphore.signal();
4066 break;
4067 }
4068 }
4069
4070 } else if (state == os::SuspendResume::SR_RUNNING) {
4071 // request was cancelled, continue
4072 } else {
4073 ShouldNotReachHere();
4074 }
4075
4076 resume_clear_context(osthread);
4077 } else if (current == os::SuspendResume::SR_RUNNING) {
4078 // request was cancelled, continue
4079 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4080 // ignore
4081 } else {
4082 // ignore
4083 }
4084
4085 errno = old_errno;
4086 }
4087
4088 static int SR_initialize() {
4089 struct sigaction act;
4090 char *s;
4091
4092 // Get signal number to use for suspend/resume
4093 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4094 int sig = ::strtol(s, 0, 10);
4095 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4096 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4097 SR_signum = sig;
4098 } else {
4099 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4100 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4101 }
4102 }
4103
4104 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4105 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4106
4107 sigemptyset(&SR_sigset);
4108 sigaddset(&SR_sigset, SR_signum);
4109
4110 // Set up signal handler for suspend/resume
4111 act.sa_flags = SA_RESTART|SA_SIGINFO;
4112 act.sa_handler = (void (*)(int)) SR_handler;
4113
4114 // SR_signum is blocked by default.
4115 // 4528190 - We also need to block pthread restart signal (32 on all
4116 // supported Linux platforms). Note that LinuxThreads need to block
4117 // this signal for all threads to work properly. So we don't have
4118 // to use hard-coded signal number when setting up the mask.
4119 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4120
4121 if (sigaction(SR_signum, &act, 0) == -1) {
4122 return -1;
4123 }
4124
4125 // Save signal flag
4126 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4127 return 0;
4128 }
4129
4130 static int sr_notify(OSThread* osthread) {
4131 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4132 assert_status(status == 0, status, "pthread_kill");
4133 return status;
4134 }
4135
4136 // "Randomly" selected value for how long we want to spin
4137 // before bailing out on suspending a thread, also how often
4138 // we send a signal to a thread we want to resume
4139 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4140 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4141
4142 // returns true on success and false on error - really an error is fatal
4143 // but this seems the normal response to library errors
4144 static bool do_suspend(OSThread* osthread) {
4145 assert(osthread->sr.is_running(), "thread should be running");
4146 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4147
4148 // mark as suspended and send signal
4149 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4150 // failed to switch, state wasn't running?
4151 ShouldNotReachHere();
4152 return false;
4153 }
4154
4155 if (sr_notify(osthread) != 0) {
4156 ShouldNotReachHere();
4157 }
4158
4159 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4160 while (true) {
4161 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4162 break;
4163 } else {
4164 // timeout
4165 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4166 if (cancelled == os::SuspendResume::SR_RUNNING) {
4167 return false;
4168 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4169 // make sure that we consume the signal on the semaphore as well
4170 sr_semaphore.wait();
4171 break;
4172 } else {
4173 ShouldNotReachHere();
4174 return false;
4175 }
4176 }
4177 }
4178
4179 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4180 return true;
4181 }
4182
4183 static void do_resume(OSThread* osthread) {
4184 assert(osthread->sr.is_suspended(), "thread should be suspended");
4185 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4186
4187 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4188 // failed to switch to WAKEUP_REQUEST
4189 ShouldNotReachHere();
4190 return;
4191 }
4192
4193 while (true) {
4194 if (sr_notify(osthread) == 0) {
4195 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4196 if (osthread->sr.is_running()) {
4197 return;
4198 }
4199 }
4200 } else {
4201 ShouldNotReachHere();
4202 }
4203 }
4204
4205 guarantee(osthread->sr.is_running(), "Must be running!");
4206 }
4207
4208 ///////////////////////////////////////////////////////////////////////////////////
4209 // signal handling (except suspend/resume)
4210
4211 // This routine may be used by user applications as a "hook" to catch signals.
4212 // The user-defined signal handler must pass unrecognized signals to this
4213 // routine, and if it returns true (non-zero), then the signal handler must
4214 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4215 // routine will never retun false (zero), but instead will execute a VM panic
4216 // routine kill the process.
4217 //
4218 // If this routine returns false, it is OK to call it again. This allows
4219 // the user-defined signal handler to perform checks either before or after
4220 // the VM performs its own checks. Naturally, the user code would be making
4221 // a serious error if it tried to handle an exception (such as a null check
4222 // or breakpoint) that the VM was generating for its own correct operation.
4223 //
4224 // This routine may recognize any of the following kinds of signals:
4225 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4226 // It should be consulted by handlers for any of those signals.
4227 //
4228 // The caller of this routine must pass in the three arguments supplied
4229 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4230 // field of the structure passed to sigaction(). This routine assumes that
4231 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4232 //
4233 // Note that the VM will print warnings if it detects conflicting signal
4234 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4235 //
4236 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4237 siginfo_t* siginfo,
4238 void* ucontext,
4239 int abort_if_unrecognized);
4240
4241 void signalHandler(int sig, siginfo_t* info, void* uc) {
4242 assert(info != NULL && uc != NULL, "it must be old kernel");
4243 int orig_errno = errno; // Preserve errno value over signal handler.
4244 JVM_handle_linux_signal(sig, info, uc, true);
4245 errno = orig_errno;
4246 }
4247
4248
4249 // This boolean allows users to forward their own non-matching signals
4250 // to JVM_handle_linux_signal, harmlessly.
4251 bool os::Linux::signal_handlers_are_installed = false;
4252
4253 // For signal-chaining
4254 struct sigaction sigact[NSIG];
4255 uint64_t sigs = 0;
4256 #if (64 < NSIG-1)
4257 #error "Not all signals can be encoded in sigs. Adapt its type!"
4258 #endif
4259 bool os::Linux::libjsig_is_loaded = false;
4260 typedef struct sigaction *(*get_signal_t)(int);
4261 get_signal_t os::Linux::get_signal_action = NULL;
4262
4263 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4264 struct sigaction *actp = NULL;
4265
4266 if (libjsig_is_loaded) {
4267 // Retrieve the old signal handler from libjsig
4268 actp = (*get_signal_action)(sig);
4269 }
4270 if (actp == NULL) {
4271 // Retrieve the preinstalled signal handler from jvm
4272 actp = get_preinstalled_handler(sig);
4273 }
4274
4275 return actp;
4276 }
4277
4278 static bool call_chained_handler(struct sigaction *actp, int sig,
4279 siginfo_t *siginfo, void *context) {
4280 // Call the old signal handler
4281 if (actp->sa_handler == SIG_DFL) {
4282 // It's more reasonable to let jvm treat it as an unexpected exception
4283 // instead of taking the default action.
4284 return false;
4285 } else if (actp->sa_handler != SIG_IGN) {
4286 if ((actp->sa_flags & SA_NODEFER) == 0) {
4287 // automaticlly block the signal
4288 sigaddset(&(actp->sa_mask), sig);
4289 }
4290
4291 sa_handler_t hand = NULL;
4292 sa_sigaction_t sa = NULL;
4293 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4294 // retrieve the chained handler
4295 if (siginfo_flag_set) {
4296 sa = actp->sa_sigaction;
4297 } else {
4298 hand = actp->sa_handler;
4299 }
4300
4301 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4302 actp->sa_handler = SIG_DFL;
4303 }
4304
4305 // try to honor the signal mask
4306 sigset_t oset;
4307 sigemptyset(&oset);
4308 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4309
4310 // call into the chained handler
4311 if (siginfo_flag_set) {
4312 (*sa)(sig, siginfo, context);
4313 } else {
4314 (*hand)(sig);
4315 }
4316
4317 // restore the signal mask
4318 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4319 }
4320 // Tell jvm's signal handler the signal is taken care of.
4321 return true;
4322 }
4323
4324 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4325 bool chained = false;
4326 // signal-chaining
4327 if (UseSignalChaining) {
4328 struct sigaction *actp = get_chained_signal_action(sig);
4329 if (actp != NULL) {
4330 chained = call_chained_handler(actp, sig, siginfo, context);
4331 }
4332 }
4333 return chained;
4334 }
4335
4336 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4337 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4338 return &sigact[sig];
4339 }
4340 return NULL;
4341 }
4342
4343 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4344 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4345 sigact[sig] = oldAct;
4346 sigs |= (uint64_t)1 << (sig-1);
4347 }
4348
4349 // for diagnostic
4350 int sigflags[NSIG];
4351
4352 int os::Linux::get_our_sigflags(int sig) {
4353 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4354 return sigflags[sig];
4355 }
4356
4357 void os::Linux::set_our_sigflags(int sig, int flags) {
4358 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4359 if (sig > 0 && sig < NSIG) {
4360 sigflags[sig] = flags;
4361 }
4362 }
4363
4364 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4365 // Check for overwrite.
4366 struct sigaction oldAct;
4367 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4368
4369 void* oldhand = oldAct.sa_sigaction
4370 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4371 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4372 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4373 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4374 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4375 if (AllowUserSignalHandlers || !set_installed) {
4376 // Do not overwrite; user takes responsibility to forward to us.
4377 return;
4378 } else if (UseSignalChaining) {
4379 // save the old handler in jvm
4380 save_preinstalled_handler(sig, oldAct);
4381 // libjsig also interposes the sigaction() call below and saves the
4382 // old sigaction on it own.
4383 } else {
4384 fatal("Encountered unexpected pre-existing sigaction handler "
4385 "%#lx for signal %d.", (long)oldhand, sig);
4386 }
4387 }
4388
4389 struct sigaction sigAct;
4390 sigfillset(&(sigAct.sa_mask));
4391 sigAct.sa_handler = SIG_DFL;
4392 if (!set_installed) {
4393 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4394 } else {
4395 sigAct.sa_sigaction = signalHandler;
4396 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4397 }
4398 // Save flags, which are set by ours
4399 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4400 sigflags[sig] = sigAct.sa_flags;
4401
4402 int ret = sigaction(sig, &sigAct, &oldAct);
4403 assert(ret == 0, "check");
4404
4405 void* oldhand2 = oldAct.sa_sigaction
4406 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4407 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4408 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4409 }
4410
4411 // install signal handlers for signals that HotSpot needs to
4412 // handle in order to support Java-level exception handling.
4413
4414 void os::Linux::install_signal_handlers() {
4415 if (!signal_handlers_are_installed) {
4416 signal_handlers_are_installed = true;
4417
4418 // signal-chaining
4419 typedef void (*signal_setting_t)();
4420 signal_setting_t begin_signal_setting = NULL;
4421 signal_setting_t end_signal_setting = NULL;
4422 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4423 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4424 if (begin_signal_setting != NULL) {
4425 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4426 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4427 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4428 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4429 libjsig_is_loaded = true;
4430 assert(UseSignalChaining, "should enable signal-chaining");
4431 }
4432 if (libjsig_is_loaded) {
4433 // Tell libjsig jvm is setting signal handlers
4434 (*begin_signal_setting)();
4435 }
4436
4437 set_signal_handler(SIGSEGV, true);
4438 set_signal_handler(SIGPIPE, true);
4439 set_signal_handler(SIGBUS, true);
4440 set_signal_handler(SIGILL, true);
4441 set_signal_handler(SIGFPE, true);
4442 #if defined(PPC64)
4443 set_signal_handler(SIGTRAP, true);
4444 #endif
4445 set_signal_handler(SIGXFSZ, true);
4446
4447 if (libjsig_is_loaded) {
4448 // Tell libjsig jvm finishes setting signal handlers
4449 (*end_signal_setting)();
4450 }
4451
4452 // We don't activate signal checker if libjsig is in place, we trust ourselves
4453 // and if UserSignalHandler is installed all bets are off.
4454 // Log that signal checking is off only if -verbose:jni is specified.
4455 if (CheckJNICalls) {
4456 if (libjsig_is_loaded) {
4457 if (PrintJNIResolving) {
4458 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4459 }
4460 check_signals = false;
4461 }
4462 if (AllowUserSignalHandlers) {
4463 if (PrintJNIResolving) {
4464 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4465 }
4466 check_signals = false;
4467 }
4468 }
4469 }
4470 }
4471
4472 // This is the fastest way to get thread cpu time on Linux.
4473 // Returns cpu time (user+sys) for any thread, not only for current.
4474 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4475 // It might work on 2.6.10+ with a special kernel/glibc patch.
4476 // For reference, please, see IEEE Std 1003.1-2004:
4477 // http://www.unix.org/single_unix_specification
4478
4479 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4480 struct timespec tp;
4481 int rc = os::Linux::clock_gettime(clockid, &tp);
4482 assert(rc == 0, "clock_gettime is expected to return 0 code");
4483
4484 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4485 }
4486
4487 void os::Linux::initialize_os_info() {
4488 assert(_os_version == 0, "OS info already initialized");
4489
4490 struct utsname _uname;
4491
4492 uint32_t major;
4493 uint32_t minor;
4494 uint32_t fix;
4495
4496 int rc;
4497
4498 // Kernel version is unknown if
4499 // verification below fails.
4500 _os_version = 0x01000000;
4501
4502 rc = uname(&_uname);
4503 if (rc != -1) {
4504
4505 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4506 if (rc == 3) {
4507
4508 if (major < 256 && minor < 256 && fix < 256) {
4509 // Kernel version format is as expected,
4510 // set it overriding unknown state.
4511 _os_version = (major << 16) |
4512 (minor << 8 ) |
4513 (fix << 0 ) ;
4514 }
4515 }
4516 }
4517 }
4518
4519 uint32_t os::Linux::os_version() {
4520 assert(_os_version != 0, "not initialized");
4521 return _os_version & 0x00FFFFFF;
4522 }
4523
4524 bool os::Linux::os_version_is_known() {
4525 assert(_os_version != 0, "not initialized");
4526 return _os_version & 0x01000000 ? false : true;
4527 }
4528
4529 /////
4530 // glibc on Linux platform uses non-documented flag
4531 // to indicate, that some special sort of signal
4532 // trampoline is used.
4533 // We will never set this flag, and we should
4534 // ignore this flag in our diagnostic
4535 #ifdef SIGNIFICANT_SIGNAL_MASK
4536 #undef SIGNIFICANT_SIGNAL_MASK
4537 #endif
4538 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4539
4540 static const char* get_signal_handler_name(address handler,
4541 char* buf, int buflen) {
4542 int offset = 0;
4543 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4544 if (found) {
4545 // skip directory names
4546 const char *p1, *p2;
4547 p1 = buf;
4548 size_t len = strlen(os::file_separator());
4549 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4550 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4551 } else {
4552 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4553 }
4554 return buf;
4555 }
4556
4557 static void print_signal_handler(outputStream* st, int sig,
4558 char* buf, size_t buflen) {
4559 struct sigaction sa;
4560
4561 sigaction(sig, NULL, &sa);
4562
4563 // See comment for SIGNIFICANT_SIGNAL_MASK define
4564 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4565
4566 st->print("%s: ", os::exception_name(sig, buf, buflen));
4567
4568 address handler = (sa.sa_flags & SA_SIGINFO)
4569 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4570 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4571
4572 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4573 st->print("SIG_DFL");
4574 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4575 st->print("SIG_IGN");
4576 } else {
4577 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4578 }
4579
4580 st->print(", sa_mask[0]=");
4581 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4582
4583 address rh = VMError::get_resetted_sighandler(sig);
4584 // May be, handler was resetted by VMError?
4585 if (rh != NULL) {
4586 handler = rh;
4587 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4588 }
4589
4590 st->print(", sa_flags=");
4591 os::Posix::print_sa_flags(st, sa.sa_flags);
4592
4593 // Check: is it our handler?
4594 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4595 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4596 // It is our signal handler
4597 // check for flags, reset system-used one!
4598 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4599 st->print(
4600 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4601 os::Linux::get_our_sigflags(sig));
4602 }
4603 }
4604 st->cr();
4605 }
4606
4607
4608 #define DO_SIGNAL_CHECK(sig) \
4609 do { \
4610 if (!sigismember(&check_signal_done, sig)) { \
4611 os::Linux::check_signal_handler(sig); \
4612 } \
4613 } while (0)
4614
4615 // This method is a periodic task to check for misbehaving JNI applications
4616 // under CheckJNI, we can add any periodic checks here
4617
4618 void os::run_periodic_checks() {
4619 if (check_signals == false) return;
4620
4621 // SEGV and BUS if overridden could potentially prevent
4622 // generation of hs*.log in the event of a crash, debugging
4623 // such a case can be very challenging, so we absolutely
4624 // check the following for a good measure:
4625 DO_SIGNAL_CHECK(SIGSEGV);
4626 DO_SIGNAL_CHECK(SIGILL);
4627 DO_SIGNAL_CHECK(SIGFPE);
4628 DO_SIGNAL_CHECK(SIGBUS);
4629 DO_SIGNAL_CHECK(SIGPIPE);
4630 DO_SIGNAL_CHECK(SIGXFSZ);
4631 #if defined(PPC64)
4632 DO_SIGNAL_CHECK(SIGTRAP);
4633 #endif
4634
4635 // ReduceSignalUsage allows the user to override these handlers
4636 // see comments at the very top and jvm_solaris.h
4637 if (!ReduceSignalUsage) {
4638 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4639 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4640 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4641 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4642 }
4643
4644 DO_SIGNAL_CHECK(SR_signum);
4645 }
4646
4647 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4648
4649 static os_sigaction_t os_sigaction = NULL;
4650
4651 void os::Linux::check_signal_handler(int sig) {
4652 char buf[O_BUFLEN];
4653 address jvmHandler = NULL;
4654
4655
4656 struct sigaction act;
4657 if (os_sigaction == NULL) {
4658 // only trust the default sigaction, in case it has been interposed
4659 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4660 if (os_sigaction == NULL) return;
4661 }
4662
4663 os_sigaction(sig, (struct sigaction*)NULL, &act);
4664
4665
4666 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4667
4668 address thisHandler = (act.sa_flags & SA_SIGINFO)
4669 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4670 : CAST_FROM_FN_PTR(address, act.sa_handler);
4671
4672
4673 switch (sig) {
4674 case SIGSEGV:
4675 case SIGBUS:
4676 case SIGFPE:
4677 case SIGPIPE:
4678 case SIGILL:
4679 case SIGXFSZ:
4680 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4681 break;
4682
4683 case SHUTDOWN1_SIGNAL:
4684 case SHUTDOWN2_SIGNAL:
4685 case SHUTDOWN3_SIGNAL:
4686 case BREAK_SIGNAL:
4687 jvmHandler = (address)user_handler();
4688 break;
4689
4690 default:
4691 if (sig == SR_signum) {
4692 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4693 } else {
4694 return;
4695 }
4696 break;
4697 }
4698
4699 if (thisHandler != jvmHandler) {
4700 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4701 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4702 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4703 // No need to check this sig any longer
4704 sigaddset(&check_signal_done, sig);
4705 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4706 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4707 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4708 exception_name(sig, buf, O_BUFLEN));
4709 }
4710 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4711 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4712 tty->print("expected:");
4713 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4714 tty->cr();
4715 tty->print(" found:");
4716 os::Posix::print_sa_flags(tty, act.sa_flags);
4717 tty->cr();
4718 // No need to check this sig any longer
4719 sigaddset(&check_signal_done, sig);
4720 }
4721
4722 // Dump all the signal
4723 if (sigismember(&check_signal_done, sig)) {
4724 print_signal_handlers(tty, buf, O_BUFLEN);
4725 }
4726 }
4727
4728 extern void report_error(char* file_name, int line_no, char* title,
4729 char* format, ...);
4730
4731 // this is called _before_ the most of global arguments have been parsed
4732 void os::init(void) {
4733 char dummy; // used to get a guess on initial stack address
4734 // first_hrtime = gethrtime();
4735
4736 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4737
4738 init_random(1234567);
4739
4740 ThreadCritical::initialize();
4741
4742 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4743 if (Linux::page_size() == -1) {
4744 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4745 os::strerror(errno));
4746 }
4747 init_page_sizes((size_t) Linux::page_size());
4748
4749 Linux::initialize_system_info();
4750
4751 Linux::initialize_os_info();
4752
4753 // main_thread points to the aboriginal thread
4754 Linux::_main_thread = pthread_self();
4755
4756 Linux::clock_init();
4757 initial_time_count = javaTimeNanos();
4758
4759 // pthread_condattr initialization for monotonic clock
4760 int status;
4761 pthread_condattr_t* _condattr = os::Linux::condAttr();
4762 if ((status = pthread_condattr_init(_condattr)) != 0) {
4763 fatal("pthread_condattr_init: %s", os::strerror(status));
4764 }
4765 // Only set the clock if CLOCK_MONOTONIC is available
4766 if (os::supports_monotonic_clock()) {
4767 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4768 if (status == EINVAL) {
4769 warning("Unable to use monotonic clock with relative timed-waits" \
4770 " - changes to the time-of-day clock may have adverse affects");
4771 } else {
4772 fatal("pthread_condattr_setclock: %s", os::strerror(status));
4773 }
4774 }
4775 }
4776 // else it defaults to CLOCK_REALTIME
4777
4778 // retrieve entry point for pthread_setname_np
4779 Linux::_pthread_setname_np =
4780 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4781
4782 }
4783
4784 // To install functions for atexit system call
4785 extern "C" {
4786 static void perfMemory_exit_helper() {
4787 perfMemory_exit();
4788 }
4789 }
4790
4791 // this is called _after_ the global arguments have been parsed
4792 jint os::init_2(void) {
4793 Linux::fast_thread_clock_init();
4794
4795 // Allocate a single page and mark it as readable for safepoint polling
4796 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4797 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4798
4799 os::set_polling_page(polling_page);
4800 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4801
4802 if (!UseMembar) {
4803 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4804 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4805 os::set_memory_serialize_page(mem_serialize_page);
4806 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4807 }
4808
4809 // initialize suspend/resume support - must do this before signal_sets_init()
4810 if (SR_initialize() != 0) {
4811 perror("SR_initialize failed");
4812 return JNI_ERR;
4813 }
4814
4815 Linux::signal_sets_init();
4816 Linux::install_signal_handlers();
4817
4818 // Check and sets minimum stack sizes against command line options
4819 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
4820 return JNI_ERR;
4821 }
4822 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4823
4824 #if defined(IA32)
4825 workaround_expand_exec_shield_cs_limit();
4826 #endif
4827
4828 Linux::libpthread_init();
4829 log_info(os)("HotSpot is running with %s, %s",
4830 Linux::glibc_version(), Linux::libpthread_version());
4831
4832 if (UseNUMA) {
4833 if (!Linux::libnuma_init()) {
4834 UseNUMA = false;
4835 } else {
4836 if ((Linux::numa_max_node() < 1)) {
4837 // There's only one node(they start from 0), disable NUMA.
4838 UseNUMA = false;
4839 }
4840 }
4841 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4842 // we can make the adaptive lgrp chunk resizing work. If the user specified
4843 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4844 // disable adaptive resizing.
4845 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4846 if (FLAG_IS_DEFAULT(UseNUMA)) {
4847 UseNUMA = false;
4848 } else {
4849 if (FLAG_IS_DEFAULT(UseLargePages) &&
4850 FLAG_IS_DEFAULT(UseSHM) &&
4851 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4852 UseLargePages = false;
4853 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4854 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4855 UseAdaptiveSizePolicy = false;
4856 UseAdaptiveNUMAChunkSizing = false;
4857 }
4858 }
4859 }
4860 if (!UseNUMA && ForceNUMA) {
4861 UseNUMA = true;
4862 }
4863 }
4864
4865 if (MaxFDLimit) {
4866 // set the number of file descriptors to max. print out error
4867 // if getrlimit/setrlimit fails but continue regardless.
4868 struct rlimit nbr_files;
4869 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4870 if (status != 0) {
4871 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4872 } else {
4873 nbr_files.rlim_cur = nbr_files.rlim_max;
4874 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4875 if (status != 0) {
4876 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4877 }
4878 }
4879 }
4880
4881 // Initialize lock used to serialize thread creation (see os::create_thread)
4882 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4883
4884 // at-exit methods are called in the reverse order of their registration.
4885 // atexit functions are called on return from main or as a result of a
4886 // call to exit(3C). There can be only 32 of these functions registered
4887 // and atexit() does not set errno.
4888
4889 if (PerfAllowAtExitRegistration) {
4890 // only register atexit functions if PerfAllowAtExitRegistration is set.
4891 // atexit functions can be delayed until process exit time, which
4892 // can be problematic for embedded VM situations. Embedded VMs should
4893 // call DestroyJavaVM() to assure that VM resources are released.
4894
4895 // note: perfMemory_exit_helper atexit function may be removed in
4896 // the future if the appropriate cleanup code can be added to the
4897 // VM_Exit VMOperation's doit method.
4898 if (atexit(perfMemory_exit_helper) != 0) {
4899 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4900 }
4901 }
4902
4903 // initialize thread priority policy
4904 prio_init();
4905
4906 return JNI_OK;
4907 }
4908
4909 // Mark the polling page as unreadable
4910 void os::make_polling_page_unreadable(void) {
4911 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4912 fatal("Could not disable polling page");
4913 }
4914 }
4915
4916 // Mark the polling page as readable
4917 void os::make_polling_page_readable(void) {
4918 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4919 fatal("Could not enable polling page");
4920 }
4921 }
4922
4923 // older glibc versions don't have this macro (which expands to
4924 // an optimized bit-counting function) so we have to roll our own
4925 #ifndef CPU_COUNT
4926
4927 static int _cpu_count(const cpu_set_t* cpus) {
4928 int count = 0;
4929 // only look up to the number of configured processors
4930 for (int i = 0; i < os::processor_count(); i++) {
4931 if (CPU_ISSET(i, cpus)) {
4932 count++;
4933 }
4934 }
4935 return count;
4936 }
4937
4938 #define CPU_COUNT(cpus) _cpu_count(cpus)
4939
4940 #endif // CPU_COUNT
4941
4942 // Get the current number of available processors for this process.
4943 // This value can change at any time during a process's lifetime.
4944 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4945 // If it appears there may be more than 1024 processors then we do a
4946 // dynamic check - see 6515172 for details.
4947 // If anything goes wrong we fallback to returning the number of online
4948 // processors - which can be greater than the number available to the process.
4949 int os::active_processor_count() {
4950 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4951 cpu_set_t* cpus_p = &cpus;
4952 int cpus_size = sizeof(cpu_set_t);
4953
4954 int configured_cpus = processor_count(); // upper bound on available cpus
4955 int cpu_count = 0;
4956
4957 // old build platforms may not support dynamic cpu sets
4958 #ifdef CPU_ALLOC
4959
4960 // To enable easy testing of the dynamic path on different platforms we
4961 // introduce a diagnostic flag: UseCpuAllocPath
4962 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4963 // kernel may use a mask bigger than cpu_set_t
4964 log_trace(os)("active_processor_count: using dynamic path %s"
4965 "- configured processors: %d",
4966 UseCpuAllocPath ? "(forced) " : "",
4967 configured_cpus);
4968 cpus_p = CPU_ALLOC(configured_cpus);
4969 if (cpus_p != NULL) {
4970 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4971 // zero it just to be safe
4972 CPU_ZERO_S(cpus_size, cpus_p);
4973 }
4974 else {
4975 // failed to allocate so fallback to online cpus
4976 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4977 log_trace(os)("active_processor_count: "
4978 "CPU_ALLOC failed (%s) - using "
4979 "online processor count: %d",
4980 os::strerror(errno), online_cpus);
4981 return online_cpus;
4982 }
4983 }
4984 else {
4985 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4986 configured_cpus);
4987 }
4988 #else // CPU_ALLOC
4989 // these stubs won't be executed
4990 #define CPU_COUNT_S(size, cpus) -1
4991 #define CPU_FREE(cpus)
4992
4993 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4994 configured_cpus);
4995 #endif // CPU_ALLOC
4996
4997 // pid 0 means the current thread - which we have to assume represents the process
4998 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4999 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5000 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
5001 }
5002 else {
5003 cpu_count = CPU_COUNT(cpus_p);
5004 }
5005 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5006 }
5007 else {
5008 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5009 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5010 "which may exceed available processors", os::strerror(errno), cpu_count);
5011 }
5012
5013 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5014 CPU_FREE(cpus_p);
5015 }
5016
5017 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
5018 return cpu_count;
5019 }
5020
5021 void os::set_native_thread_name(const char *name) {
5022 if (Linux::_pthread_setname_np) {
5023 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5024 snprintf(buf, sizeof(buf), "%s", name);
5025 buf[sizeof(buf) - 1] = '\0';
5026 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5027 // ERANGE should not happen; all other errors should just be ignored.
5028 assert(rc != ERANGE, "pthread_setname_np failed");
5029 }
5030 }
5031
5032 bool os::distribute_processes(uint length, uint* distribution) {
5033 // Not yet implemented.
5034 return false;
5035 }
5036
5037 bool os::bind_to_processor(uint processor_id) {
5038 // Not yet implemented.
5039 return false;
5040 }
5041
5042 ///
5043
5044 void os::SuspendedThreadTask::internal_do_task() {
5045 if (do_suspend(_thread->osthread())) {
5046 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5047 do_task(context);
5048 do_resume(_thread->osthread());
5049 }
5050 }
5051
5052 class PcFetcher : public os::SuspendedThreadTask {
5053 public:
5054 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5055 ExtendedPC result();
5056 protected:
5057 void do_task(const os::SuspendedThreadTaskContext& context);
5058 private:
5059 ExtendedPC _epc;
5060 };
5061
5062 ExtendedPC PcFetcher::result() {
5063 guarantee(is_done(), "task is not done yet.");
5064 return _epc;
5065 }
5066
5067 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5068 Thread* thread = context.thread();
5069 OSThread* osthread = thread->osthread();
5070 if (osthread->ucontext() != NULL) {
5071 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5072 } else {
5073 // NULL context is unexpected, double-check this is the VMThread
5074 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5075 }
5076 }
5077
5078 // Suspends the target using the signal mechanism and then grabs the PC before
5079 // resuming the target. Used by the flat-profiler only
5080 ExtendedPC os::get_thread_pc(Thread* thread) {
5081 // Make sure that it is called by the watcher for the VMThread
5082 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5083 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5084
5085 PcFetcher fetcher(thread);
5086 fetcher.run();
5087 return fetcher.result();
5088 }
5089
5090 ////////////////////////////////////////////////////////////////////////////////
5091 // debug support
5092
5093 bool os::find(address addr, outputStream* st) {
5094 Dl_info dlinfo;
5095 memset(&dlinfo, 0, sizeof(dlinfo));
5096 if (dladdr(addr, &dlinfo) != 0) {
5097 st->print(PTR_FORMAT ": ", p2i(addr));
5098 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5099 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5100 p2i(addr) - p2i(dlinfo.dli_saddr));
5101 } else if (dlinfo.dli_fbase != NULL) {
5102 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5103 } else {
5104 st->print("<absolute address>");
5105 }
5106 if (dlinfo.dli_fname != NULL) {
5107 st->print(" in %s", dlinfo.dli_fname);
5108 }
5109 if (dlinfo.dli_fbase != NULL) {
5110 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5111 }
5112 st->cr();
5113
5114 if (Verbose) {
5115 // decode some bytes around the PC
5116 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5117 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5118 address lowest = (address) dlinfo.dli_sname;
5119 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5120 if (begin < lowest) begin = lowest;
5121 Dl_info dlinfo2;
5122 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5123 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5124 end = (address) dlinfo2.dli_saddr;
5125 }
5126 Disassembler::decode(begin, end, st);
5127 }
5128 return true;
5129 }
5130 return false;
5131 }
5132
5133 ////////////////////////////////////////////////////////////////////////////////
5134 // misc
5135
5136 // This does not do anything on Linux. This is basically a hook for being
5137 // able to use structured exception handling (thread-local exception filters)
5138 // on, e.g., Win32.
5139 void
5140 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5141 JavaCallArguments* args, Thread* thread) {
5142 f(value, method, args, thread);
5143 }
5144
5145 void os::print_statistics() {
5146 }
5147
5148 bool os::message_box(const char* title, const char* message) {
5149 int i;
5150 fdStream err(defaultStream::error_fd());
5151 for (i = 0; i < 78; i++) err.print_raw("=");
5152 err.cr();
5153 err.print_raw_cr(title);
5154 for (i = 0; i < 78; i++) err.print_raw("-");
5155 err.cr();
5156 err.print_raw_cr(message);
5157 for (i = 0; i < 78; i++) err.print_raw("=");
5158 err.cr();
5159
5160 char buf[16];
5161 // Prevent process from exiting upon "read error" without consuming all CPU
5162 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5163
5164 return buf[0] == 'y' || buf[0] == 'Y';
5165 }
5166
5167 int os::stat(const char *path, struct stat *sbuf) {
5168 char pathbuf[MAX_PATH];
5169 if (strlen(path) > MAX_PATH - 1) {
5170 errno = ENAMETOOLONG;
5171 return -1;
5172 }
5173 os::native_path(strcpy(pathbuf, path));
5174 return ::stat(pathbuf, sbuf);
5175 }
5176
5177 // Is a (classpath) directory empty?
5178 bool os::dir_is_empty(const char* path) {
5179 DIR *dir = NULL;
5180 struct dirent *ptr;
5181
5182 dir = opendir(path);
5183 if (dir == NULL) return true;
5184
5185 // Scan the directory
5186 bool result = true;
5187 char buf[sizeof(struct dirent) + MAX_PATH];
5188 while (result && (ptr = ::readdir(dir)) != NULL) {
5189 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5190 result = false;
5191 }
5192 }
5193 closedir(dir);
5194 return result;
5195 }
5196
5197 // This code originates from JDK's sysOpen and open64_w
5198 // from src/solaris/hpi/src/system_md.c
5199
5200 int os::open(const char *path, int oflag, int mode) {
5201 if (strlen(path) > MAX_PATH - 1) {
5202 errno = ENAMETOOLONG;
5203 return -1;
5204 }
5205
5206 // All file descriptors that are opened in the Java process and not
5207 // specifically destined for a subprocess should have the close-on-exec
5208 // flag set. If we don't set it, then careless 3rd party native code
5209 // might fork and exec without closing all appropriate file descriptors
5210 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5211 // turn might:
5212 //
5213 // - cause end-of-file to fail to be detected on some file
5214 // descriptors, resulting in mysterious hangs, or
5215 //
5216 // - might cause an fopen in the subprocess to fail on a system
5217 // suffering from bug 1085341.
5218 //
5219 // (Yes, the default setting of the close-on-exec flag is a Unix
5220 // design flaw)
5221 //
5222 // See:
5223 // 1085341: 32-bit stdio routines should support file descriptors >255
5224 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5225 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5226 //
5227 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5228 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5229 // because it saves a system call and removes a small window where the flag
5230 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5231 // and we fall back to using FD_CLOEXEC (see below).
5232 #ifdef O_CLOEXEC
5233 oflag |= O_CLOEXEC;
5234 #endif
5235
5236 int fd = ::open64(path, oflag, mode);
5237 if (fd == -1) return -1;
5238
5239 //If the open succeeded, the file might still be a directory
5240 {
5241 struct stat64 buf64;
5242 int ret = ::fstat64(fd, &buf64);
5243 int st_mode = buf64.st_mode;
5244
5245 if (ret != -1) {
5246 if ((st_mode & S_IFMT) == S_IFDIR) {
5247 errno = EISDIR;
5248 ::close(fd);
5249 return -1;
5250 }
5251 } else {
5252 ::close(fd);
5253 return -1;
5254 }
5255 }
5256
5257 #ifdef FD_CLOEXEC
5258 // Validate that the use of the O_CLOEXEC flag on open above worked.
5259 // With recent kernels, we will perform this check exactly once.
5260 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5261 if (!O_CLOEXEC_is_known_to_work) {
5262 int flags = ::fcntl(fd, F_GETFD);
5263 if (flags != -1) {
5264 if ((flags & FD_CLOEXEC) != 0)
5265 O_CLOEXEC_is_known_to_work = 1;
5266 else
5267 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5268 }
5269 }
5270 #endif
5271
5272 return fd;
5273 }
5274
5275
5276 // create binary file, rewriting existing file if required
5277 int os::create_binary_file(const char* path, bool rewrite_existing) {
5278 int oflags = O_WRONLY | O_CREAT;
5279 if (!rewrite_existing) {
5280 oflags |= O_EXCL;
5281 }
5282 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5283 }
5284
5285 // return current position of file pointer
5286 jlong os::current_file_offset(int fd) {
5287 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5288 }
5289
5290 // move file pointer to the specified offset
5291 jlong os::seek_to_file_offset(int fd, jlong offset) {
5292 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5293 }
5294
5295 // This code originates from JDK's sysAvailable
5296 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5297
5298 int os::available(int fd, jlong *bytes) {
5299 jlong cur, end;
5300 int mode;
5301 struct stat64 buf64;
5302
5303 if (::fstat64(fd, &buf64) >= 0) {
5304 mode = buf64.st_mode;
5305 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5306 int n;
5307 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5308 *bytes = n;
5309 return 1;
5310 }
5311 }
5312 }
5313 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5314 return 0;
5315 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5316 return 0;
5317 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5318 return 0;
5319 }
5320 *bytes = end - cur;
5321 return 1;
5322 }
5323
5324 // Map a block of memory.
5325 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5326 char *addr, size_t bytes, bool read_only,
5327 bool allow_exec) {
5328 int prot;
5329 int flags = MAP_PRIVATE;
5330
5331 if (read_only) {
5332 prot = PROT_READ;
5333 } else {
5334 prot = PROT_READ | PROT_WRITE;
5335 }
5336
5337 if (allow_exec) {
5338 prot |= PROT_EXEC;
5339 }
5340
5341 if (addr != NULL) {
5342 flags |= MAP_FIXED;
5343 }
5344
5345 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5346 fd, file_offset);
5347 if (mapped_address == MAP_FAILED) {
5348 return NULL;
5349 }
5350 return mapped_address;
5351 }
5352
5353
5354 // Remap a block of memory.
5355 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5356 char *addr, size_t bytes, bool read_only,
5357 bool allow_exec) {
5358 // same as map_memory() on this OS
5359 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5360 allow_exec);
5361 }
5362
5363
5364 // Unmap a block of memory.
5365 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5366 return munmap(addr, bytes) == 0;
5367 }
5368
5369 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5370
5371 static clockid_t thread_cpu_clockid(Thread* thread) {
5372 pthread_t tid = thread->osthread()->pthread_id();
5373 clockid_t clockid;
5374
5375 // Get thread clockid
5376 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5377 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5378 return clockid;
5379 }
5380
5381 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5382 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5383 // of a thread.
5384 //
5385 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5386 // the fast estimate available on the platform.
5387
5388 jlong os::current_thread_cpu_time() {
5389 if (os::Linux::supports_fast_thread_cpu_time()) {
5390 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5391 } else {
5392 // return user + sys since the cost is the same
5393 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5394 }
5395 }
5396
5397 jlong os::thread_cpu_time(Thread* thread) {
5398 // consistent with what current_thread_cpu_time() returns
5399 if (os::Linux::supports_fast_thread_cpu_time()) {
5400 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5401 } else {
5402 return slow_thread_cpu_time(thread, true /* user + sys */);
5403 }
5404 }
5405
5406 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5407 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5408 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5409 } else {
5410 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5411 }
5412 }
5413
5414 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5415 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5416 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5417 } else {
5418 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5419 }
5420 }
5421
5422 // -1 on error.
5423 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5424 pid_t tid = thread->osthread()->thread_id();
5425 char *s;
5426 char stat[2048];
5427 int statlen;
5428 char proc_name[64];
5429 int count;
5430 long sys_time, user_time;
5431 char cdummy;
5432 int idummy;
5433 long ldummy;
5434 FILE *fp;
5435
5436 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5437 fp = fopen(proc_name, "r");
5438 if (fp == NULL) return -1;
5439 statlen = fread(stat, 1, 2047, fp);
5440 stat[statlen] = '\0';
5441 fclose(fp);
5442
5443 // Skip pid and the command string. Note that we could be dealing with
5444 // weird command names, e.g. user could decide to rename java launcher
5445 // to "java 1.4.2 :)", then the stat file would look like
5446 // 1234 (java 1.4.2 :)) R ... ...
5447 // We don't really need to know the command string, just find the last
5448 // occurrence of ")" and then start parsing from there. See bug 4726580.
5449 s = strrchr(stat, ')');
5450 if (s == NULL) return -1;
5451
5452 // Skip blank chars
5453 do { s++; } while (s && isspace(*s));
5454
5455 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5456 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5457 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5458 &user_time, &sys_time);
5459 if (count != 13) return -1;
5460 if (user_sys_cpu_time) {
5461 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5462 } else {
5463 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5464 }
5465 }
5466
5467 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5468 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5469 info_ptr->may_skip_backward = false; // elapsed time not wall time
5470 info_ptr->may_skip_forward = false; // elapsed time not wall time
5471 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5472 }
5473
5474 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5475 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5476 info_ptr->may_skip_backward = false; // elapsed time not wall time
5477 info_ptr->may_skip_forward = false; // elapsed time not wall time
5478 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5479 }
5480
5481 bool os::is_thread_cpu_time_supported() {
5482 return true;
5483 }
5484
5485 // System loadavg support. Returns -1 if load average cannot be obtained.
5486 // Linux doesn't yet have a (official) notion of processor sets,
5487 // so just return the system wide load average.
5488 int os::loadavg(double loadavg[], int nelem) {
5489 return ::getloadavg(loadavg, nelem);
5490 }
5491
5492 void os::pause() {
5493 char filename[MAX_PATH];
5494 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5495 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5496 } else {
5497 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5498 }
5499
5500 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5501 if (fd != -1) {
5502 struct stat buf;
5503 ::close(fd);
5504 while (::stat(filename, &buf) == 0) {
5505 (void)::poll(NULL, 0, 100);
5506 }
5507 } else {
5508 jio_fprintf(stderr,
5509 "Could not open pause file '%s', continuing immediately.\n", filename);
5510 }
5511 }
5512
5513
5514 // Refer to the comments in os_solaris.cpp park-unpark. The next two
5515 // comment paragraphs are worth repeating here:
5516 //
5517 // Assumption:
5518 // Only one parker can exist on an event, which is why we allocate
5519 // them per-thread. Multiple unparkers can coexist.
5520 //
5521 // _Event serves as a restricted-range semaphore.
5522 // -1 : thread is blocked, i.e. there is a waiter
5523 // 0 : neutral: thread is running or ready,
5524 // could have been signaled after a wait started
5525 // 1 : signaled - thread is running or ready
5526 //
5527
5528 // utility to compute the abstime argument to timedwait:
5529 // millis is the relative timeout time
5530 // abstime will be the absolute timeout time
5531 // TODO: replace compute_abstime() with unpackTime()
5532
5533 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5534 if (millis < 0) millis = 0;
5535
5536 jlong seconds = millis / 1000;
5537 millis %= 1000;
5538 if (seconds > 50000000) { // see man cond_timedwait(3T)
5539 seconds = 50000000;
5540 }
5541
5542 if (os::supports_monotonic_clock()) {
5543 struct timespec now;
5544 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5545 assert_status(status == 0, status, "clock_gettime");
5546 abstime->tv_sec = now.tv_sec + seconds;
5547 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5548 if (nanos >= NANOSECS_PER_SEC) {
5549 abstime->tv_sec += 1;
5550 nanos -= NANOSECS_PER_SEC;
5551 }
5552 abstime->tv_nsec = nanos;
5553 } else {
5554 struct timeval now;
5555 int status = gettimeofday(&now, NULL);
5556 assert(status == 0, "gettimeofday");
5557 abstime->tv_sec = now.tv_sec + seconds;
5558 long usec = now.tv_usec + millis * 1000;
5559 if (usec >= 1000000) {
5560 abstime->tv_sec += 1;
5561 usec -= 1000000;
5562 }
5563 abstime->tv_nsec = usec * 1000;
5564 }
5565 return abstime;
5566 }
5567
5568 void os::PlatformEvent::park() { // AKA "down()"
5569 // Transitions for _Event:
5570 // -1 => -1 : illegal
5571 // 1 => 0 : pass - return immediately
5572 // 0 => -1 : block; then set _Event to 0 before returning
5573
5574 // Invariant: Only the thread associated with the Event/PlatformEvent
5575 // may call park().
5576 // TODO: assert that _Assoc != NULL or _Assoc == Self
5577 assert(_nParked == 0, "invariant");
5578
5579 int v;
5580 for (;;) {
5581 v = _Event;
5582 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5583 }
5584 guarantee(v >= 0, "invariant");
5585 if (v == 0) {
5586 // Do this the hard way by blocking ...
5587 int status = pthread_mutex_lock(_mutex);
5588 assert_status(status == 0, status, "mutex_lock");
5589 guarantee(_nParked == 0, "invariant");
5590 ++_nParked;
5591 while (_Event < 0) {
5592 status = pthread_cond_wait(_cond, _mutex);
5593 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5594 // Treat this the same as if the wait was interrupted
5595 if (status == ETIME) { status = EINTR; }
5596 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5597 }
5598 --_nParked;
5599
5600 _Event = 0;
5601 status = pthread_mutex_unlock(_mutex);
5602 assert_status(status == 0, status, "mutex_unlock");
5603 // Paranoia to ensure our locked and lock-free paths interact
5604 // correctly with each other.
5605 OrderAccess::fence();
5606 }
5607 guarantee(_Event >= 0, "invariant");
5608 }
5609
5610 int os::PlatformEvent::park(jlong millis) {
5611 // Transitions for _Event:
5612 // -1 => -1 : illegal
5613 // 1 => 0 : pass - return immediately
5614 // 0 => -1 : block; then set _Event to 0 before returning
5615
5616 guarantee(_nParked == 0, "invariant");
5617
5618 int v;
5619 for (;;) {
5620 v = _Event;
5621 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5622 }
5623 guarantee(v >= 0, "invariant");
5624 if (v != 0) return OS_OK;
5625
5626 // We do this the hard way, by blocking the thread.
5627 // Consider enforcing a minimum timeout value.
5628 struct timespec abst;
5629 compute_abstime(&abst, millis);
5630
5631 int ret = OS_TIMEOUT;
5632 int status = pthread_mutex_lock(_mutex);
5633 assert_status(status == 0, status, "mutex_lock");
5634 guarantee(_nParked == 0, "invariant");
5635 ++_nParked;
5636
5637 // Object.wait(timo) will return because of
5638 // (a) notification
5639 // (b) timeout
5640 // (c) thread.interrupt
5641 //
5642 // Thread.interrupt and object.notify{All} both call Event::set.
5643 // That is, we treat thread.interrupt as a special case of notification.
5644 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
5645 // We assume all ETIME returns are valid.
5646 //
5647 // TODO: properly differentiate simultaneous notify+interrupt.
5648 // In that case, we should propagate the notify to another waiter.
5649
5650 while (_Event < 0) {
5651 status = pthread_cond_timedwait(_cond, _mutex, &abst);
5652 assert_status(status == 0 || status == EINTR ||
5653 status == ETIME || status == ETIMEDOUT,
5654 status, "cond_timedwait");
5655 if (!FilterSpuriousWakeups) break; // previous semantics
5656 if (status == ETIME || status == ETIMEDOUT) break;
5657 // We consume and ignore EINTR and spurious wakeups.
5658 }
5659 --_nParked;
5660 if (_Event >= 0) {
5661 ret = OS_OK;
5662 }
5663 _Event = 0;
5664 status = pthread_mutex_unlock(_mutex);
5665 assert_status(status == 0, status, "mutex_unlock");
5666 assert(_nParked == 0, "invariant");
5667 // Paranoia to ensure our locked and lock-free paths interact
5668 // correctly with each other.
5669 OrderAccess::fence();
5670 return ret;
5671 }
5672
5673 void os::PlatformEvent::unpark() {
5674 // Transitions for _Event:
5675 // 0 => 1 : just return
5676 // 1 => 1 : just return
5677 // -1 => either 0 or 1; must signal target thread
5678 // That is, we can safely transition _Event from -1 to either
5679 // 0 or 1.
5680 // See also: "Semaphores in Plan 9" by Mullender & Cox
5681 //
5682 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5683 // that it will take two back-to-back park() calls for the owning
5684 // thread to block. This has the benefit of forcing a spurious return
5685 // from the first park() call after an unpark() call which will help
5686 // shake out uses of park() and unpark() without condition variables.
5687
5688 if (Atomic::xchg(1, &_Event) >= 0) return;
5689
5690 // Wait for the thread associated with the event to vacate
5691 int status = pthread_mutex_lock(_mutex);
5692 assert_status(status == 0, status, "mutex_lock");
5693 int AnyWaiters = _nParked;
5694 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5695 status = pthread_mutex_unlock(_mutex);
5696 assert_status(status == 0, status, "mutex_unlock");
5697 if (AnyWaiters != 0) {
5698 // Note that we signal() *after* dropping the lock for "immortal" Events.
5699 // This is safe and avoids a common class of futile wakeups. In rare
5700 // circumstances this can cause a thread to return prematurely from
5701 // cond_{timed}wait() but the spurious wakeup is benign and the victim
5702 // will simply re-test the condition and re-park itself.
5703 // This provides particular benefit if the underlying platform does not
5704 // provide wait morphing.
5705 status = pthread_cond_signal(_cond);
5706 assert_status(status == 0, status, "cond_signal");
5707 }
5708 }
5709
5710
5711 // JSR166
5712 // -------------------------------------------------------
5713
5714 // The solaris and linux implementations of park/unpark are fairly
5715 // conservative for now, but can be improved. They currently use a
5716 // mutex/condvar pair, plus a a count.
5717 // Park decrements count if > 0, else does a condvar wait. Unpark
5718 // sets count to 1 and signals condvar. Only one thread ever waits
5719 // on the condvar. Contention seen when trying to park implies that someone
5720 // is unparking you, so don't wait. And spurious returns are fine, so there
5721 // is no need to track notifications.
5722
5723 // This code is common to linux and solaris and will be moved to a
5724 // common place in dolphin.
5725 //
5726 // The passed in time value is either a relative time in nanoseconds
5727 // or an absolute time in milliseconds. Either way it has to be unpacked
5728 // into suitable seconds and nanoseconds components and stored in the
5729 // given timespec structure.
5730 // Given time is a 64-bit value and the time_t used in the timespec is only
5731 // a signed-32-bit value (except on 64-bit Linux) we have to watch for
5732 // overflow if times way in the future are given. Further on Solaris versions
5733 // prior to 10 there is a restriction (see cond_timedwait) that the specified
5734 // number of seconds, in abstime, is less than current_time + 100,000,000.
5735 // As it will be 28 years before "now + 100000000" will overflow we can
5736 // ignore overflow and just impose a hard-limit on seconds using the value
5737 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
5738 // years from "now".
5739
5740 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5741 assert(time > 0, "convertTime");
5742 time_t max_secs = 0;
5743
5744 if (!os::supports_monotonic_clock() || isAbsolute) {
5745 struct timeval now;
5746 int status = gettimeofday(&now, NULL);
5747 assert(status == 0, "gettimeofday");
5748
5749 max_secs = now.tv_sec + MAX_SECS;
5750
5751 if (isAbsolute) {
5752 jlong secs = time / 1000;
5753 if (secs > max_secs) {
5754 absTime->tv_sec = max_secs;
5755 } else {
5756 absTime->tv_sec = secs;
5757 }
5758 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5759 } else {
5760 jlong secs = time / NANOSECS_PER_SEC;
5761 if (secs >= MAX_SECS) {
5762 absTime->tv_sec = max_secs;
5763 absTime->tv_nsec = 0;
5764 } else {
5765 absTime->tv_sec = now.tv_sec + secs;
5766 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5767 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5768 absTime->tv_nsec -= NANOSECS_PER_SEC;
5769 ++absTime->tv_sec; // note: this must be <= max_secs
5770 }
5771 }
5772 }
5773 } else {
5774 // must be relative using monotonic clock
5775 struct timespec now;
5776 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5777 assert_status(status == 0, status, "clock_gettime");
5778 max_secs = now.tv_sec + MAX_SECS;
5779 jlong secs = time / NANOSECS_PER_SEC;
5780 if (secs >= MAX_SECS) {
5781 absTime->tv_sec = max_secs;
5782 absTime->tv_nsec = 0;
5783 } else {
5784 absTime->tv_sec = now.tv_sec + secs;
5785 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5786 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5787 absTime->tv_nsec -= NANOSECS_PER_SEC;
5788 ++absTime->tv_sec; // note: this must be <= max_secs
5789 }
5790 }
5791 }
5792 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5793 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5794 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5795 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5796 }
5797
5798 void Parker::park(bool isAbsolute, jlong time) {
5799 // Ideally we'd do something useful while spinning, such
5800 // as calling unpackTime().
5801
5802 // Optional fast-path check:
5803 // Return immediately if a permit is available.
5804 // We depend on Atomic::xchg() having full barrier semantics
5805 // since we are doing a lock-free update to _counter.
5806 if (Atomic::xchg(0, &_counter) > 0) return;
5807
5808 Thread* thread = Thread::current();
5809 assert(thread->is_Java_thread(), "Must be JavaThread");
5810 JavaThread *jt = (JavaThread *)thread;
5811
5812 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5813 // Check interrupt before trying to wait
5814 if (Thread::is_interrupted(thread, false)) {
5815 return;
5816 }
5817
5818 // Next, demultiplex/decode time arguments
5819 timespec absTime;
5820 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
5821 return;
5822 }
5823 if (time > 0) {
5824 unpackTime(&absTime, isAbsolute, time);
5825 }
5826
5827
5828 // Enter safepoint region
5829 // Beware of deadlocks such as 6317397.
5830 // The per-thread Parker:: mutex is a classic leaf-lock.
5831 // In particular a thread must never block on the Threads_lock while
5832 // holding the Parker:: mutex. If safepoints are pending both the
5833 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5834 ThreadBlockInVM tbivm(jt);
5835
5836 // Don't wait if cannot get lock since interference arises from
5837 // unblocking. Also. check interrupt before trying wait
5838 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5839 return;
5840 }
5841
5842 int status;
5843 if (_counter > 0) { // no wait needed
5844 _counter = 0;
5845 status = pthread_mutex_unlock(_mutex);
5846 assert_status(status == 0, status, "invariant");
5847 // Paranoia to ensure our locked and lock-free paths interact
5848 // correctly with each other and Java-level accesses.
5849 OrderAccess::fence();
5850 return;
5851 }
5852
5853 #ifdef ASSERT
5854 // Don't catch signals while blocked; let the running threads have the signals.
5855 // (This allows a debugger to break into the running thread.)
5856 sigset_t oldsigs;
5857 sigemptyset(&oldsigs);
5858 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5859 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5860 #endif
5861
5862 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5863 jt->set_suspend_equivalent();
5864 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5865
5866 assert(_cur_index == -1, "invariant");
5867 if (time == 0) {
5868 _cur_index = REL_INDEX; // arbitrary choice when not timed
5869 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
5870 } else {
5871 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5872 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
5873 }
5874 _cur_index = -1;
5875 assert_status(status == 0 || status == EINTR ||
5876 status == ETIME || status == ETIMEDOUT,
5877 status, "cond_timedwait");
5878
5879 #ifdef ASSERT
5880 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5881 #endif
5882
5883 _counter = 0;
5884 status = pthread_mutex_unlock(_mutex);
5885 assert_status(status == 0, status, "invariant");
5886 // Paranoia to ensure our locked and lock-free paths interact
5887 // correctly with each other and Java-level accesses.
5888 OrderAccess::fence();
5889
5890 // If externally suspended while waiting, re-suspend
5891 if (jt->handle_special_suspend_equivalent_condition()) {
5892 jt->java_suspend_self();
5893 }
5894 }
5895
5896 void Parker::unpark() {
5897 int status = pthread_mutex_lock(_mutex);
5898 assert_status(status == 0, status, "invariant");
5899 const int s = _counter;
5900 _counter = 1;
5901 // must capture correct index before unlocking
5902 int index = _cur_index;
5903 status = pthread_mutex_unlock(_mutex);
5904 assert_status(status == 0, status, "invariant");
5905 if (s < 1 && index != -1) {
5906 // thread is definitely parked
5907 status = pthread_cond_signal(&_cond[index]);
5908 assert_status(status == 0, status, "invariant");
5909 }
5910 }
5911
5912
5913 extern char** environ;
5914
5915 // Run the specified command in a separate process. Return its exit value,
5916 // or -1 on failure (e.g. can't fork a new process).
5917 // Unlike system(), this function can be called from signal handler. It
5918 // doesn't block SIGINT et al.
5919 int os::fork_and_exec(char* cmd) {
5920 const char * argv[4] = {"sh", "-c", cmd, NULL};
5921
5922 pid_t pid = fork();
5923
5924 if (pid < 0) {
5925 // fork failed
5926 return -1;
5927
5928 } else if (pid == 0) {
5929 // child process
5930
5931 execve("/bin/sh", (char* const*)argv, environ);
5932
5933 // execve failed
5934 _exit(-1);
5935
5936 } else {
5937 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5938 // care about the actual exit code, for now.
5939
5940 int status;
5941
5942 // Wait for the child process to exit. This returns immediately if
5943 // the child has already exited. */
5944 while (waitpid(pid, &status, 0) < 0) {
5945 switch (errno) {
5946 case ECHILD: return 0;
5947 case EINTR: break;
5948 default: return -1;
5949 }
5950 }
5951
5952 if (WIFEXITED(status)) {
5953 // The child exited normally; get its exit code.
5954 return WEXITSTATUS(status);
5955 } else if (WIFSIGNALED(status)) {
5956 // The child exited because of a signal
5957 // The best value to return is 0x80 + signal number,
5958 // because that is what all Unix shells do, and because
5959 // it allows callers to distinguish between process exit and
5960 // process death by signal.
5961 return 0x80 + WTERMSIG(status);
5962 } else {
5963 // Unknown exit code; pass it through
5964 return status;
5965 }
5966 }
5967 }
5968
5969 // is_headless_jre()
5970 //
5971 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5972 // in order to report if we are running in a headless jre
5973 //
5974 // Since JDK8 xawt/libmawt.so was moved into the same directory
5975 // as libawt.so, and renamed libawt_xawt.so
5976 //
5977 bool os::is_headless_jre() {
5978 struct stat statbuf;
5979 char buf[MAXPATHLEN];
5980 char libmawtpath[MAXPATHLEN];
5981 const char *xawtstr = "/xawt/libmawt.so";
5982 const char *new_xawtstr = "/libawt_xawt.so";
5983 char *p;
5984
5985 // Get path to libjvm.so
5986 os::jvm_path(buf, sizeof(buf));
5987
5988 // Get rid of libjvm.so
5989 p = strrchr(buf, '/');
5990 if (p == NULL) {
5991 return false;
5992 } else {
5993 *p = '\0';
5994 }
5995
5996 // Get rid of client or server
5997 p = strrchr(buf, '/');
5998 if (p == NULL) {
5999 return false;
6000 } else {
6001 *p = '\0';
6002 }
6003
6004 // check xawt/libmawt.so
6005 strcpy(libmawtpath, buf);
6006 strcat(libmawtpath, xawtstr);
6007 if (::stat(libmawtpath, &statbuf) == 0) return false;
6008
6009 // check libawt_xawt.so
6010 strcpy(libmawtpath, buf);
6011 strcat(libmawtpath, new_xawtstr);
6012 if (::stat(libmawtpath, &statbuf) == 0) return false;
6013
6014 return true;
6015 }
6016
6017 // Get the default path to the core file
6018 // Returns the length of the string
6019 int os::get_core_path(char* buffer, size_t bufferSize) {
6020 /*
6021 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
6022 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
6023 */
6024 const int core_pattern_len = 129;
6025 char core_pattern[core_pattern_len] = {0};
6026
6027 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
6028 if (core_pattern_file == -1) {
6029 return -1;
6030 }
6031
6032 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
6033 ::close(core_pattern_file);
6034 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
6035 return -1;
6036 }
6037 if (core_pattern[ret-1] == '\n') {
6038 core_pattern[ret-1] = '\0';
6039 } else {
6040 core_pattern[ret] = '\0';
6041 }
6042
6043 char *pid_pos = strstr(core_pattern, "%p");
6044 int written;
6045
6046 if (core_pattern[0] == '/') {
6047 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6048 } else {
6049 char cwd[PATH_MAX];
6050
6051 const char* p = get_current_directory(cwd, PATH_MAX);
6052 if (p == NULL) {
6053 return -1;
6054 }
6055
6056 if (core_pattern[0] == '|') {
6057 written = jio_snprintf(buffer, bufferSize,
6058 "\"%s\" (or dumping to %s/core.%d)",
6059 &core_pattern[1], p, current_process_id());
6060 } else {
6061 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6062 }
6063 }
6064
6065 if (written < 0) {
6066 return -1;
6067 }
6068
6069 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6070 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6071
6072 if (core_uses_pid_file != -1) {
6073 char core_uses_pid = 0;
6074 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6075 ::close(core_uses_pid_file);
6076
6077 if (core_uses_pid == '1') {
6078 jio_snprintf(buffer + written, bufferSize - written,
6079 ".%d", current_process_id());
6080 }
6081 }
6082 }
6083
6084 return strlen(buffer);
6085 }
6086
6087 bool os::start_debugging(char *buf, int buflen) {
6088 int len = (int)strlen(buf);
6089 char *p = &buf[len];
6090
6091 jio_snprintf(p, buflen-len,
6092 "\n\n"
6093 "Do you want to debug the problem?\n\n"
6094 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6095 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6096 "Otherwise, press RETURN to abort...",
6097 os::current_process_id(), os::current_process_id(),
6098 os::current_thread_id(), os::current_thread_id());
6099
6100 bool yes = os::message_box("Unexpected Error", buf);
6101
6102 if (yes) {
6103 // yes, user asked VM to launch debugger
6104 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6105 os::current_process_id(), os::current_process_id());
6106
6107 os::fork_and_exec(buf);
6108 yes = false;
6109 }
6110 return yes;
6111 }
6112
6113
6114 // Java/Compiler thread:
6115 //
6116 // Low memory addresses
6117 // P0 +------------------------+
6118 // | |\ Java thread created by VM does not have glibc
6119 // | glibc guard page | - guard page, attached Java thread usually has
6120 // | |/ 1 glibc guard page.
6121 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6122 // | |\
6123 // | HotSpot Guard Pages | - red, yellow and reserved pages
6124 // | |/
6125 // +------------------------+ JavaThread::stack_reserved_zone_base()
6126 // | |\
6127 // | Normal Stack | -
6128 // | |/
6129 // P2 +------------------------+ Thread::stack_base()
6130 //
6131 // Non-Java thread:
6132 //
6133 // Low memory addresses
6134 // P0 +------------------------+
6135 // | |\
6136 // | glibc guard page | - usually 1 page
6137 // | |/
6138 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6139 // | |\
6140 // | Normal Stack | -
6141 // | |/
6142 // P2 +------------------------+ Thread::stack_base()
6143 //
6144 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6145 // returned from pthread_attr_getstack().
6146 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6147 // of the stack size given in pthread_attr. We work around this for
6148 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6149 //
6150 #ifndef ZERO
6151 static void current_stack_region(address * bottom, size_t * size) {
6152 if (os::Linux::is_initial_thread()) {
6153 // initial thread needs special handling because pthread_getattr_np()
6154 // may return bogus value.
6155 *bottom = os::Linux::initial_thread_stack_bottom();
6156 *size = os::Linux::initial_thread_stack_size();
6157 } else {
6158 pthread_attr_t attr;
6159
6160 int rslt = pthread_getattr_np(pthread_self(), &attr);
6161
6162 // JVM needs to know exact stack location, abort if it fails
6163 if (rslt != 0) {
6164 if (rslt == ENOMEM) {
6165 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6166 } else {
6167 fatal("pthread_getattr_np failed with error = %d", rslt);
6168 }
6169 }
6170
6171 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6172 fatal("Cannot locate current stack attributes!");
6173 }
6174
6175 // Work around NPTL stack guard error.
6176 size_t guard_size = 0;
6177 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6178 if (rslt != 0) {
6179 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6180 }
6181 *bottom += guard_size;
6182 *size -= guard_size;
6183
6184 pthread_attr_destroy(&attr);
6185
6186 }
6187 assert(os::current_stack_pointer() >= *bottom &&
6188 os::current_stack_pointer() < *bottom + *size, "just checking");
6189 }
6190
6191 address os::current_stack_base() {
6192 address bottom;
6193 size_t size;
6194 current_stack_region(&bottom, &size);
6195 return (bottom + size);
6196 }
6197
6198 size_t os::current_stack_size() {
6199 // This stack size includes the usable stack and HotSpot guard pages
6200 // (for the threads that have Hotspot guard pages).
6201 address bottom;
6202 size_t size;
6203 current_stack_region(&bottom, &size);
6204 return size;
6205 }
6206 #endif
6207
6208 static inline struct timespec get_mtime(const char* filename) {
6209 struct stat st;
6210 int ret = os::stat(filename, &st);
6211 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
6212 return st.st_mtim;
6213 }
6214
6215 int os::compare_file_modified_times(const char* file1, const char* file2) {
6216 struct timespec filetime1 = get_mtime(file1);
6217 struct timespec filetime2 = get_mtime(file2);
6218 int diff = filetime1.tv_sec - filetime2.tv_sec;
6219 if (diff == 0) {
6220 return filetime1.tv_nsec - filetime2.tv_nsec;
6221 }
6222 return diff;
6223 }
6224
6225 /////////////// Unit tests ///////////////
6226
6227 #ifndef PRODUCT
6228
6229 #define test_log(...) \
6230 do { \
6231 if (VerboseInternalVMTests) { \
6232 tty->print_cr(__VA_ARGS__); \
6233 tty->flush(); \
6234 } \
6235 } while (false)
6236
6237 class TestReserveMemorySpecial : AllStatic {
6238 public:
6239 static void small_page_write(void* addr, size_t size) {
6240 size_t page_size = os::vm_page_size();
6241
6242 char* end = (char*)addr + size;
6243 for (char* p = (char*)addr; p < end; p += page_size) {
6244 *p = 1;
6245 }
6246 }
6247
6248 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6249 if (!UseHugeTLBFS) {
6250 return;
6251 }
6252
6253 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6254
6255 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6256
6257 if (addr != NULL) {
6258 small_page_write(addr, size);
6259
6260 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6261 }
6262 }
6263
6264 static void test_reserve_memory_special_huge_tlbfs_only() {
6265 if (!UseHugeTLBFS) {
6266 return;
6267 }
6268
6269 size_t lp = os::large_page_size();
6270
6271 for (size_t size = lp; size <= lp * 10; size += lp) {
6272 test_reserve_memory_special_huge_tlbfs_only(size);
6273 }
6274 }
6275
6276 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6277 size_t lp = os::large_page_size();
6278 size_t ag = os::vm_allocation_granularity();
6279
6280 // sizes to test
6281 const size_t sizes[] = {
6282 lp, lp + ag, lp + lp / 2, lp * 2,
6283 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6284 lp * 10, lp * 10 + lp / 2
6285 };
6286 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6287
6288 // For each size/alignment combination, we test three scenarios:
6289 // 1) with req_addr == NULL
6290 // 2) with a non-null req_addr at which we expect to successfully allocate
6291 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6292 // expect the allocation to either fail or to ignore req_addr
6293
6294 // Pre-allocate two areas; they shall be as large as the largest allocation
6295 // and aligned to the largest alignment we will be testing.
6296 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6297 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6298 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6299 -1, 0);
6300 assert(mapping1 != MAP_FAILED, "should work");
6301
6302 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6303 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6304 -1, 0);
6305 assert(mapping2 != MAP_FAILED, "should work");
6306
6307 // Unmap the first mapping, but leave the second mapping intact: the first
6308 // mapping will serve as a value for a "good" req_addr (case 2). The second
6309 // mapping, still intact, as "bad" req_addr (case 3).
6310 ::munmap(mapping1, mapping_size);
6311
6312 // Case 1
6313 test_log("%s, req_addr NULL:", __FUNCTION__);
6314 test_log("size align result");
6315
6316 for (int i = 0; i < num_sizes; i++) {
6317 const size_t size = sizes[i];
6318 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6319 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6320 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6321 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6322 if (p != NULL) {
6323 assert(is_ptr_aligned(p, alignment), "must be");
6324 small_page_write(p, size);
6325 os::Linux::release_memory_special_huge_tlbfs(p, size);
6326 }
6327 }
6328 }
6329
6330 // Case 2
6331 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6332 test_log("size align req_addr result");
6333
6334 for (int i = 0; i < num_sizes; i++) {
6335 const size_t size = sizes[i];
6336 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6337 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6338 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6339 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6340 size, alignment, p2i(req_addr), p2i(p),
6341 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6342 if (p != NULL) {
6343 assert(p == req_addr, "must be");
6344 small_page_write(p, size);
6345 os::Linux::release_memory_special_huge_tlbfs(p, size);
6346 }
6347 }
6348 }
6349
6350 // Case 3
6351 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6352 test_log("size align req_addr result");
6353
6354 for (int i = 0; i < num_sizes; i++) {
6355 const size_t size = sizes[i];
6356 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6357 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6358 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6359 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6360 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6361 // as the area around req_addr contains already existing mappings, the API should always
6362 // return NULL (as per contract, it cannot return another address)
6363 assert(p == NULL, "must be");
6364 }
6365 }
6366
6367 ::munmap(mapping2, mapping_size);
6368
6369 }
6370
6371 static void test_reserve_memory_special_huge_tlbfs() {
6372 if (!UseHugeTLBFS) {
6373 return;
6374 }
6375
6376 test_reserve_memory_special_huge_tlbfs_only();
6377 test_reserve_memory_special_huge_tlbfs_mixed();
6378 }
6379
6380 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6381 if (!UseSHM) {
6382 return;
6383 }
6384
6385 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6386
6387 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6388
6389 if (addr != NULL) {
6390 assert(is_ptr_aligned(addr, alignment), "Check");
6391 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6392
6393 small_page_write(addr, size);
6394
6395 os::Linux::release_memory_special_shm(addr, size);
6396 }
6397 }
6398
6399 static void test_reserve_memory_special_shm() {
6400 size_t lp = os::large_page_size();
6401 size_t ag = os::vm_allocation_granularity();
6402
6403 for (size_t size = ag; size < lp * 3; size += ag) {
6404 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6405 test_reserve_memory_special_shm(size, alignment);
6406 }
6407 }
6408 }
6409
6410 static void test() {
6411 test_reserve_memory_special_huge_tlbfs();
6412 test_reserve_memory_special_shm();
6413 }
6414 };
6415
6416 void TestReserveMemorySpecial_test() {
6417 TestReserveMemorySpecial::test();
6418 }
6419
6420 #endif