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 "mutex_linux.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_linux.inline.hpp"
41 #include "os_share_linux.hpp"
42 #include "prims/jniFastGetField.hpp"
43 #include "prims/jvm.h"
44 #include "prims/jvm_misc.hpp"
45 #include "runtime/arguments.hpp"
46 #include "runtime/atomic.inline.hpp"
47 #include "runtime/extendedPC.hpp"
48 #include "runtime/globals.hpp"
49 #include "runtime/interfaceSupport.hpp"
50 #include "runtime/init.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/javaCalls.hpp"
53 #include "runtime/mutexLocker.hpp"
54 #include "runtime/objectMonitor.hpp"
55 #include "runtime/orderAccess.inline.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/perfMemory.hpp"
58 #include "runtime/sharedRuntime.hpp"
59 #include "runtime/statSampler.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/thread.inline.hpp"
62 #include "runtime/threadCritical.hpp"
63 #include "runtime/timer.hpp"
64 #include "semaphore_posix.hpp"
65 #include "services/attachListener.hpp"
66 #include "services/memTracker.hpp"
67 #include "services/runtimeService.hpp"
68 #include "utilities/decoder.hpp"
69 #include "utilities/defaultStream.hpp"
70 #include "utilities/events.hpp"
71 #include "utilities/elfFile.hpp"
72 #include "utilities/growableArray.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/vmError.hpp"
75
76 // put OS-includes here
77 # include <sys/types.h>
78 # include <sys/mman.h>
79 # include <sys/stat.h>
80 # include <sys/select.h>
81 # include <pthread.h>
82 # include <signal.h>
83 # include <errno.h>
84 # include <dlfcn.h>
85 # include <stdio.h>
86 # include <unistd.h>
87 # include <sys/resource.h>
88 # include <pthread.h>
89 # include <sys/stat.h>
90 # include <sys/time.h>
91 # include <sys/times.h>
92 # include <sys/utsname.h>
93 # include <sys/socket.h>
94 # include <sys/wait.h>
95 # include <pwd.h>
96 # include <poll.h>
97 # include <semaphore.h>
98 # include <fcntl.h>
99 # include <string.h>
100 # include <syscall.h>
101 # include <sys/sysinfo.h>
102 # include <gnu/libc-version.h>
103 # include <sys/ipc.h>
104 # include <sys/shm.h>
105 # include <link.h>
106 # include <stdint.h>
107 # include <inttypes.h>
108 # include <sys/ioctl.h>
109
110 #ifndef _GNU_SOURCE
111 #define _GNU_SOURCE
112 #include <sched.h>
113 #undef _GNU_SOURCE
114 #else
115 #include <sched.h>
116 #endif
117
118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
119 // getrusage() is prepared to handle the associated failure.
120 #ifndef RUSAGE_THREAD
121 #define RUSAGE_THREAD (1) /* only the calling thread */
122 #endif
123
124 #define MAX_PATH (2 * K)
125
126 #define MAX_SECS 100000000
127
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130
131 #define LARGEPAGES_BIT (1 << 6)
132 ////////////////////////////////////////////////////////////////////////////////
133 // global variables
134 julong os::Linux::_physical_memory = 0;
135
136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
138
139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
142 Mutex* os::Linux::_createThread_lock = NULL;
143 pthread_t os::Linux::_main_thread;
144 int os::Linux::_page_size = -1;
145 const int os::Linux::_vm_default_page_size = (8 * K);
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 uint32_t os::Linux::_os_version = 0;
148 const char * os::Linux::_glibc_version = NULL;
149 const char * os::Linux::_libpthread_version = NULL;
150 pthread_condattr_t os::Linux::_condattr[1];
151
152 static jlong initial_time_count=0;
153
154 static int clock_tics_per_sec = 100;
155
156 // For diagnostics to print a message once. see run_periodic_checks
157 static sigset_t check_signal_done;
158 static bool check_signals = true;
159
160 // Signal number used to suspend/resume a thread
161
162 // do not use any signal number less than SIGSEGV, see 4355769
163 static int SR_signum = SIGUSR2;
164 sigset_t SR_sigset;
165
166 // Declarations
167 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
168
169 // utility functions
170
171 static int SR_initialize();
172
173 julong os::available_memory() {
174 return Linux::available_memory();
175 }
176
177 julong os::Linux::available_memory() {
178 // values in struct sysinfo are "unsigned long"
179 struct sysinfo si;
180 sysinfo(&si);
181
182 return (julong)si.freeram * si.mem_unit;
183 }
184
185 julong os::physical_memory() {
186 return Linux::physical_memory();
187 }
188
189 // Return true if user is running as root.
190
191 bool os::have_special_privileges() {
192 static bool init = false;
193 static bool privileges = false;
194 if (!init) {
195 privileges = (getuid() != geteuid()) || (getgid() != getegid());
196 init = true;
197 }
198 return privileges;
199 }
200
201
202 #ifndef SYS_gettid
203 // i386: 224, ia64: 1105, amd64: 186, sparc 143
204 #ifdef __ia64__
205 #define SYS_gettid 1105
206 #else
207 #ifdef __i386__
208 #define SYS_gettid 224
209 #else
210 #ifdef __amd64__
211 #define SYS_gettid 186
212 #else
213 #ifdef __sparc__
214 #define SYS_gettid 143
215 #else
216 #error define gettid for the arch
217 #endif
218 #endif
219 #endif
220 #endif
221 #endif
222
223 // Cpu architecture string
224 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
225
226
227 // pid_t gettid()
228 //
229 // Returns the kernel thread id of the currently running thread. Kernel
230 // thread id is used to access /proc.
231 pid_t os::Linux::gettid() {
232 int rslt = syscall(SYS_gettid);
233 assert(rslt != -1, "must be."); // old linuxthreads implementation?
234 return (pid_t)rslt;
235 }
236
237 // Most versions of linux have a bug where the number of processors are
238 // determined by looking at the /proc file system. In a chroot environment,
239 // the system call returns 1. This causes the VM to act as if it is
240 // a single processor and elide locking (see is_MP() call).
241 static bool unsafe_chroot_detected = false;
242 static const char *unstable_chroot_error = "/proc file system not found.\n"
243 "Java may be unstable running multithreaded in a chroot "
244 "environment on Linux when /proc filesystem is not mounted.";
245
246 void os::Linux::initialize_system_info() {
247 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
248 if (processor_count() == 1) {
249 pid_t pid = os::Linux::gettid();
250 char fname[32];
251 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
252 FILE *fp = fopen(fname, "r");
253 if (fp == NULL) {
254 unsafe_chroot_detected = true;
255 } else {
256 fclose(fp);
257 }
258 }
259 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
260 assert(processor_count() > 0, "linux error");
261 }
262
263 void os::init_system_properties_values() {
264 // The next steps are taken in the product version:
265 //
266 // Obtain the JAVA_HOME value from the location of libjvm.so.
267 // This library should be located at:
268 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
269 //
270 // If "/jre/lib/" appears at the right place in the path, then we
271 // assume libjvm.so is installed in a JDK and we use this path.
272 //
273 // Otherwise exit with message: "Could not create the Java virtual machine."
274 //
275 // The following extra steps are taken in the debugging version:
276 //
277 // If "/jre/lib/" does NOT appear at the right place in the path
278 // instead of exit check for $JAVA_HOME environment variable.
279 //
280 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
281 // then we append a fake suffix "hotspot/libjvm.so" to this path so
282 // it looks like libjvm.so is installed there
283 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
284 //
285 // Otherwise exit.
286 //
287 // Important note: if the location of libjvm.so changes this
288 // code needs to be changed accordingly.
289
290 // See ld(1):
291 // The linker uses the following search paths to locate required
292 // shared libraries:
293 // 1: ...
294 // ...
295 // 7: The default directories, normally /lib and /usr/lib.
296 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
297 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
298 #else
299 #define DEFAULT_LIBPATH "/lib:/usr/lib"
300 #endif
301
302 // Base path of extensions installed on the system.
303 #define SYS_EXT_DIR "/usr/java/packages"
304 #define EXTENSIONS_DIR "/lib/ext"
305
306 // Buffer that fits several sprintfs.
307 // Note that the space for the colon and the trailing null are provided
308 // by the nulls included by the sizeof operator.
309 const size_t bufsize =
310 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
311 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
312 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
313
314 // sysclasspath, java_home, dll_dir
315 {
316 char *pslash;
317 os::jvm_path(buf, bufsize);
318
319 // Found the full path to libjvm.so.
320 // Now cut the path to <java_home>/jre if we can.
321 pslash = strrchr(buf, '/');
322 if (pslash != NULL) {
323 *pslash = '\0'; // Get rid of /libjvm.so.
324 }
325 pslash = strrchr(buf, '/');
326 if (pslash != NULL) {
327 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
328 }
329 Arguments::set_dll_dir(buf);
330
331 if (pslash != NULL) {
332 pslash = strrchr(buf, '/');
333 if (pslash != NULL) {
334 *pslash = '\0'; // Get rid of /<arch>.
335 pslash = strrchr(buf, '/');
336 if (pslash != NULL) {
337 *pslash = '\0'; // Get rid of /lib.
338 }
339 }
340 }
341 Arguments::set_java_home(buf);
342 set_boot_path('/', ':');
343 }
344
345 // Where to look for native libraries.
346 //
347 // Note: Due to a legacy implementation, most of the library path
348 // is set in the launcher. This was to accomodate linking restrictions
349 // on legacy Linux implementations (which are no longer supported).
350 // Eventually, all the library path setting will be done here.
351 //
352 // However, to prevent the proliferation of improperly built native
353 // libraries, the new path component /usr/java/packages is added here.
354 // Eventually, all the library path setting will be done here.
355 {
356 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
357 // should always exist (until the legacy problem cited above is
358 // addressed).
359 const char *v = ::getenv("LD_LIBRARY_PATH");
360 const char *v_colon = ":";
361 if (v == NULL) { v = ""; v_colon = ""; }
362 // That's +1 for the colon and +1 for the trailing '\0'.
363 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
364 strlen(v) + 1 +
365 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
366 mtInternal);
367 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
368 Arguments::set_library_path(ld_library_path);
369 FREE_C_HEAP_ARRAY(char, ld_library_path);
370 }
371
372 // Extensions directories.
373 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
374 Arguments::set_ext_dirs(buf);
375
376 FREE_C_HEAP_ARRAY(char, buf);
377
378 #undef DEFAULT_LIBPATH
379 #undef SYS_EXT_DIR
380 #undef EXTENSIONS_DIR
381 }
382
383 ////////////////////////////////////////////////////////////////////////////////
384 // breakpoint support
385
386 void os::breakpoint() {
387 BREAKPOINT;
388 }
389
390 extern "C" void breakpoint() {
391 // use debugger to set breakpoint here
392 }
393
394 ////////////////////////////////////////////////////////////////////////////////
395 // signal support
396
397 debug_only(static bool signal_sets_initialized = false);
398 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
399
400 bool os::Linux::is_sig_ignored(int sig) {
401 struct sigaction oact;
402 sigaction(sig, (struct sigaction*)NULL, &oact);
403 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
404 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
405 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
406 return true;
407 } else {
408 return false;
409 }
410 }
411
412 void os::Linux::signal_sets_init() {
413 // Should also have an assertion stating we are still single-threaded.
414 assert(!signal_sets_initialized, "Already initialized");
415 // Fill in signals that are necessarily unblocked for all threads in
416 // the VM. Currently, we unblock the following signals:
417 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
418 // by -Xrs (=ReduceSignalUsage));
419 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
420 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
421 // the dispositions or masks wrt these signals.
422 // Programs embedding the VM that want to use the above signals for their
423 // own purposes must, at this time, use the "-Xrs" option to prevent
424 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
425 // (See bug 4345157, and other related bugs).
426 // In reality, though, unblocking these signals is really a nop, since
427 // these signals are not blocked by default.
428 sigemptyset(&unblocked_sigs);
429 sigemptyset(&allowdebug_blocked_sigs);
430 sigaddset(&unblocked_sigs, SIGILL);
431 sigaddset(&unblocked_sigs, SIGSEGV);
432 sigaddset(&unblocked_sigs, SIGBUS);
433 sigaddset(&unblocked_sigs, SIGFPE);
434 #if defined(PPC64)
435 sigaddset(&unblocked_sigs, SIGTRAP);
436 #endif
437 sigaddset(&unblocked_sigs, SR_signum);
438
439 if (!ReduceSignalUsage) {
440 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
441 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
442 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
443 }
444 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
445 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
446 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
447 }
448 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
449 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
450 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
451 }
452 }
453 // Fill in signals that are blocked by all but the VM thread.
454 sigemptyset(&vm_sigs);
455 if (!ReduceSignalUsage) {
456 sigaddset(&vm_sigs, BREAK_SIGNAL);
457 }
458 debug_only(signal_sets_initialized = true);
459
460 }
461
462 // These are signals that are unblocked while a thread is running Java.
463 // (For some reason, they get blocked by default.)
464 sigset_t* os::Linux::unblocked_signals() {
465 assert(signal_sets_initialized, "Not initialized");
466 return &unblocked_sigs;
467 }
468
469 // These are the signals that are blocked while a (non-VM) thread is
470 // running Java. Only the VM thread handles these signals.
471 sigset_t* os::Linux::vm_signals() {
472 assert(signal_sets_initialized, "Not initialized");
473 return &vm_sigs;
474 }
475
476 // These are signals that are blocked during cond_wait to allow debugger in
477 sigset_t* os::Linux::allowdebug_blocked_signals() {
478 assert(signal_sets_initialized, "Not initialized");
479 return &allowdebug_blocked_sigs;
480 }
481
482 void os::Linux::hotspot_sigmask(Thread* thread) {
483
484 //Save caller's signal mask before setting VM signal mask
485 sigset_t caller_sigmask;
486 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
487
488 OSThread* osthread = thread->osthread();
489 osthread->set_caller_sigmask(caller_sigmask);
490
491 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
492
493 if (!ReduceSignalUsage) {
494 if (thread->is_VM_thread()) {
495 // Only the VM thread handles BREAK_SIGNAL ...
496 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
497 } else {
498 // ... all other threads block BREAK_SIGNAL
499 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
500 }
501 }
502 }
503
504 //////////////////////////////////////////////////////////////////////////////
505 // detecting pthread library
506
507 void os::Linux::libpthread_init() {
508 // Save glibc and pthread version strings.
509 #if !defined(_CS_GNU_LIBC_VERSION) || \
510 !defined(_CS_GNU_LIBPTHREAD_VERSION)
511 #error "glibc too old (< 2.3.2)"
512 #endif
513
514 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
515 assert(n > 0, "cannot retrieve glibc version");
516 char *str = (char *)malloc(n, mtInternal);
517 confstr(_CS_GNU_LIBC_VERSION, str, n);
518 os::Linux::set_glibc_version(str);
519
520 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
521 assert(n > 0, "cannot retrieve pthread version");
522 str = (char *)malloc(n, mtInternal);
523 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
524 os::Linux::set_libpthread_version(str);
525 }
526
527 /////////////////////////////////////////////////////////////////////////////
528 // thread stack expansion
529
530 // os::Linux::manually_expand_stack() takes care of expanding the thread
531 // stack. Note that this is normally not needed: pthread stacks allocate
532 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
533 // committed. Therefore it is not necessary to expand the stack manually.
534 //
535 // Manually expanding the stack was historically needed on LinuxThreads
536 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
537 // it is kept to deal with very rare corner cases:
538 //
539 // For one, user may run the VM on an own implementation of threads
540 // whose stacks are - like the old LinuxThreads - implemented using
541 // mmap(MAP_GROWSDOWN).
542 //
543 // Also, this coding may be needed if the VM is running on the primordial
544 // thread. Normally we avoid running on the primordial thread; however,
545 // user may still invoke the VM on the primordial thread.
546 //
547 // The following historical comment describes the details about running
548 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
549
550
551 // Force Linux kernel to expand current thread stack. If "bottom" is close
552 // to the stack guard, caller should block all signals.
553 //
554 // MAP_GROWSDOWN:
555 // A special mmap() flag that is used to implement thread stacks. It tells
556 // kernel that the memory region should extend downwards when needed. This
557 // allows early versions of LinuxThreads to only mmap the first few pages
558 // when creating a new thread. Linux kernel will automatically expand thread
559 // stack as needed (on page faults).
560 //
561 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
562 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
563 // region, it's hard to tell if the fault is due to a legitimate stack
564 // access or because of reading/writing non-exist memory (e.g. buffer
565 // overrun). As a rule, if the fault happens below current stack pointer,
566 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
567 // application (see Linux kernel fault.c).
568 //
569 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
570 // stack overflow detection.
571 //
572 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
573 // not use MAP_GROWSDOWN.
574 //
575 // To get around the problem and allow stack banging on Linux, we need to
576 // manually expand thread stack after receiving the SIGSEGV.
577 //
578 // There are two ways to expand thread stack to address "bottom", we used
579 // both of them in JVM before 1.5:
580 // 1. adjust stack pointer first so that it is below "bottom", and then
581 // touch "bottom"
582 // 2. mmap() the page in question
583 //
584 // Now alternate signal stack is gone, it's harder to use 2. For instance,
585 // if current sp is already near the lower end of page 101, and we need to
586 // call mmap() to map page 100, it is possible that part of the mmap() frame
587 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
588 // That will destroy the mmap() frame and cause VM to crash.
589 //
590 // The following code works by adjusting sp first, then accessing the "bottom"
591 // page to force a page fault. Linux kernel will then automatically expand the
592 // stack mapping.
593 //
594 // _expand_stack_to() assumes its frame size is less than page size, which
595 // should always be true if the function is not inlined.
596
597 static void NOINLINE _expand_stack_to(address bottom) {
598 address sp;
599 size_t size;
600 volatile char *p;
601
602 // Adjust bottom to point to the largest address within the same page, it
603 // gives us a one-page buffer if alloca() allocates slightly more memory.
604 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
605 bottom += os::Linux::page_size() - 1;
606
607 // sp might be slightly above current stack pointer; if that's the case, we
608 // will alloca() a little more space than necessary, which is OK. Don't use
609 // os::current_stack_pointer(), as its result can be slightly below current
610 // stack pointer, causing us to not alloca enough to reach "bottom".
611 sp = (address)&sp;
612
613 if (sp > bottom) {
614 size = sp - bottom;
615 p = (volatile char *)alloca(size);
616 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
617 p[0] = '\0';
618 }
619 }
620
621 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
622 assert(t!=NULL, "just checking");
623 assert(t->osthread()->expanding_stack(), "expand should be set");
624 assert(t->stack_base() != NULL, "stack_base was not initialized");
625
626 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
627 sigset_t mask_all, old_sigset;
628 sigfillset(&mask_all);
629 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
630 _expand_stack_to(addr);
631 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
632 return true;
633 }
634 return false;
635 }
636
637 //////////////////////////////////////////////////////////////////////////////
638 // create new thread
639
640 // Thread start routine for all newly created threads
641 static void *thread_native_entry(Thread *thread) {
642 // Try to randomize the cache line index of hot stack frames.
643 // This helps when threads of the same stack traces evict each other's
644 // cache lines. The threads can be either from the same JVM instance, or
645 // from different JVM instances. The benefit is especially true for
646 // processors with hyperthreading technology.
647 static int counter = 0;
648 int pid = os::current_process_id();
649 alloca(((pid ^ counter++) & 7) * 128);
650
651 thread->initialize_thread_current();
652
653 OSThread* osthread = thread->osthread();
654 Monitor* sync = osthread->startThread_lock();
655
656 osthread->set_thread_id(os::current_thread_id());
657
658 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
659 os::current_thread_id(), (uintx) pthread_self());
660
661 if (UseNUMA) {
662 int lgrp_id = os::numa_get_group_id();
663 if (lgrp_id != -1) {
664 thread->set_lgrp_id(lgrp_id);
665 }
666 }
667 // initialize signal mask for this thread
668 os::Linux::hotspot_sigmask(thread);
669
670 // initialize floating point control register
671 os::Linux::init_thread_fpu_state();
672
673 // handshaking with parent thread
674 {
675 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
676
677 // notify parent thread
678 osthread->set_state(INITIALIZED);
679 sync->notify_all();
680
681 // wait until os::start_thread()
682 while (osthread->get_state() == INITIALIZED) {
683 sync->wait(Mutex::_no_safepoint_check_flag);
684 }
685 }
686
687 // call one more level start routine
688 thread->run();
689
690 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
691 os::current_thread_id(), (uintx) pthread_self());
692
693 // If a thread has not deleted itself ("delete this") as part of its
694 // termination sequence, we have to ensure thread-local-storage is
695 // cleared before we actually terminate. No threads should ever be
696 // deleted asynchronously with respect to their termination.
697 if (Thread::current_or_null_safe() != NULL) {
698 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
699 thread->clear_thread_current();
700 }
701
702 return 0;
703 }
704
705 bool os::create_thread(Thread* thread, ThreadType thr_type,
706 size_t stack_size) {
707 assert(thread->osthread() == NULL, "caller responsible");
708
709 // Allocate the OSThread object
710 OSThread* osthread = new OSThread(NULL, NULL);
711 if (osthread == NULL) {
712 return false;
713 }
714
715 // set the correct thread state
716 osthread->set_thread_type(thr_type);
717
718 // Initial state is ALLOCATED but not INITIALIZED
719 osthread->set_state(ALLOCATED);
720
721 thread->set_osthread(osthread);
722
723 // init thread attributes
724 pthread_attr_t attr;
725 pthread_attr_init(&attr);
726 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
727
728 // stack size
729 // calculate stack size if it's not specified by caller
730 if (stack_size == 0) {
731 stack_size = os::Linux::default_stack_size(thr_type);
732
733 switch (thr_type) {
734 case os::java_thread:
735 // Java threads use ThreadStackSize which default value can be
736 // changed with the flag -Xss
737 assert(JavaThread::stack_size_at_create() > 0, "this should be set");
738 stack_size = JavaThread::stack_size_at_create();
739 break;
740 case os::compiler_thread:
741 if (CompilerThreadStackSize > 0) {
742 stack_size = (size_t)(CompilerThreadStackSize * K);
743 break;
744 } // else fall through:
745 // use VMThreadStackSize if CompilerThreadStackSize is not defined
746 case os::vm_thread:
747 case os::pgc_thread:
748 case os::cgc_thread:
749 case os::watcher_thread:
750 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
751 break;
752 }
753 }
754
755 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
756 pthread_attr_setstacksize(&attr, stack_size);
757
758 // glibc guard page
759 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
760
761 ThreadState state;
762
763 {
764 pthread_t tid;
765 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
766
767 char buf[64];
768 if (ret == 0) {
769 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
770 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
771 } else {
772 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
773 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
774 }
775
776 pthread_attr_destroy(&attr);
777
778 if (ret != 0) {
779 // Need to clean up stuff we've allocated so far
780 thread->set_osthread(NULL);
781 delete osthread;
782 return false;
783 }
784
785 // Store pthread info into the OSThread
786 osthread->set_pthread_id(tid);
787
788 // Wait until child thread is either initialized or aborted
789 {
790 Monitor* sync_with_child = osthread->startThread_lock();
791 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
792 while ((state = osthread->get_state()) == ALLOCATED) {
793 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
794 }
795 }
796 }
797
798 // Aborted due to thread limit being reached
799 if (state == ZOMBIE) {
800 thread->set_osthread(NULL);
801 delete osthread;
802 return false;
803 }
804
805 // The thread is returned suspended (in state INITIALIZED),
806 // and is started higher up in the call chain
807 assert(state == INITIALIZED, "race condition");
808 return true;
809 }
810
811 /////////////////////////////////////////////////////////////////////////////
812 // attach existing thread
813
814 // bootstrap the main thread
815 bool os::create_main_thread(JavaThread* thread) {
816 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
817 return create_attached_thread(thread);
818 }
819
820 bool os::create_attached_thread(JavaThread* thread) {
821 #ifdef ASSERT
822 thread->verify_not_published();
823 #endif
824
825 // Allocate the OSThread object
826 OSThread* osthread = new OSThread(NULL, NULL);
827
828 if (osthread == NULL) {
829 return false;
830 }
831
832 // Store pthread info into the OSThread
833 osthread->set_thread_id(os::Linux::gettid());
834 osthread->set_pthread_id(::pthread_self());
835
836 // initialize floating point control register
837 os::Linux::init_thread_fpu_state();
838
839 // Initial thread state is RUNNABLE
840 osthread->set_state(RUNNABLE);
841
842 thread->set_osthread(osthread);
843
844 if (UseNUMA) {
845 int lgrp_id = os::numa_get_group_id();
846 if (lgrp_id != -1) {
847 thread->set_lgrp_id(lgrp_id);
848 }
849 }
850
851 if (os::Linux::is_initial_thread()) {
852 // If current thread is initial thread, its stack is mapped on demand,
853 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
854 // the entire stack region to avoid SEGV in stack banging.
855 // It is also useful to get around the heap-stack-gap problem on SuSE
856 // kernel (see 4821821 for details). We first expand stack to the top
857 // of yellow zone, then enable stack yellow zone (order is significant,
858 // enabling yellow zone first will crash JVM on SuSE Linux), so there
859 // is no gap between the last two virtual memory regions.
860
861 JavaThread *jt = (JavaThread *)thread;
862 address addr = jt->stack_reserved_zone_base();
863 assert(addr != NULL, "initialization problem?");
864 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
865
866 osthread->set_expanding_stack();
867 os::Linux::manually_expand_stack(jt, addr);
868 osthread->clear_expanding_stack();
869 }
870
871 // initialize signal mask for this thread
872 // and save the caller's signal mask
873 os::Linux::hotspot_sigmask(thread);
874
875 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
876 os::current_thread_id(), (uintx) pthread_self());
877
878 return true;
879 }
880
881 void os::pd_start_thread(Thread* thread) {
882 OSThread * osthread = thread->osthread();
883 assert(osthread->get_state() != INITIALIZED, "just checking");
884 Monitor* sync_with_child = osthread->startThread_lock();
885 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
886 sync_with_child->notify();
887 }
888
889 // Free Linux resources related to the OSThread
890 void os::free_thread(OSThread* osthread) {
891 assert(osthread != NULL, "osthread not set");
892
893 // We are told to free resources of the argument thread,
894 // but we can only really operate on the current thread.
895 assert(Thread::current()->osthread() == osthread,
896 "os::free_thread but not current thread");
897
898 #ifdef ASSERT
899 sigset_t current;
900 sigemptyset(¤t);
901 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
902 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
903 #endif
904
905 // Restore caller's signal mask
906 sigset_t sigmask = osthread->caller_sigmask();
907 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
908
909 delete osthread;
910 }
911
912 //////////////////////////////////////////////////////////////////////////////
913 // initial thread
914
915 // Check if current thread is the initial thread, similar to Solaris thr_main.
916 bool os::Linux::is_initial_thread(void) {
917 char dummy;
918 // If called before init complete, thread stack bottom will be null.
919 // Can be called if fatal error occurs before initialization.
920 if (initial_thread_stack_bottom() == NULL) return false;
921 assert(initial_thread_stack_bottom() != NULL &&
922 initial_thread_stack_size() != 0,
923 "os::init did not locate initial thread's stack region");
924 if ((address)&dummy >= initial_thread_stack_bottom() &&
925 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
926 return true;
927 } else {
928 return false;
929 }
930 }
931
932 // Find the virtual memory area that contains addr
933 static bool find_vma(address addr, address* vma_low, address* vma_high) {
934 FILE *fp = fopen("/proc/self/maps", "r");
935 if (fp) {
936 address low, high;
937 while (!feof(fp)) {
938 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
939 if (low <= addr && addr < high) {
940 if (vma_low) *vma_low = low;
941 if (vma_high) *vma_high = high;
942 fclose(fp);
943 return true;
944 }
945 }
946 for (;;) {
947 int ch = fgetc(fp);
948 if (ch == EOF || ch == (int)'\n') break;
949 }
950 }
951 fclose(fp);
952 }
953 return false;
954 }
955
956 // Locate initial thread stack. This special handling of initial thread stack
957 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
958 // bogus value for initial thread.
959 void os::Linux::capture_initial_stack(size_t max_size) {
960 // stack size is the easy part, get it from RLIMIT_STACK
961 size_t stack_size;
962 struct rlimit rlim;
963 getrlimit(RLIMIT_STACK, &rlim);
964 stack_size = rlim.rlim_cur;
965
966 // 6308388: a bug in ld.so will relocate its own .data section to the
967 // lower end of primordial stack; reduce ulimit -s value a little bit
968 // so we won't install guard page on ld.so's data section.
969 stack_size -= 2 * page_size();
970
971 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
972 // 7.1, in both cases we will get 2G in return value.
973 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
974 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
975 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
976 // in case other parts in glibc still assumes 2M max stack size.
977 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
978 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
979 if (stack_size > 2 * K * K IA64_ONLY(*2)) {
980 stack_size = 2 * K * K IA64_ONLY(*2);
981 }
982 // Try to figure out where the stack base (top) is. This is harder.
983 //
984 // When an application is started, glibc saves the initial stack pointer in
985 // a global variable "__libc_stack_end", which is then used by system
986 // libraries. __libc_stack_end should be pretty close to stack top. The
987 // variable is available since the very early days. However, because it is
988 // a private interface, it could disappear in the future.
989 //
990 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
991 // to __libc_stack_end, it is very close to stack top, but isn't the real
992 // stack top. Note that /proc may not exist if VM is running as a chroot
993 // program, so reading /proc/<pid>/stat could fail. Also the contents of
994 // /proc/<pid>/stat could change in the future (though unlikely).
995 //
996 // We try __libc_stack_end first. If that doesn't work, look for
997 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
998 // as a hint, which should work well in most cases.
999
1000 uintptr_t stack_start;
1001
1002 // try __libc_stack_end first
1003 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1004 if (p && *p) {
1005 stack_start = *p;
1006 } else {
1007 // see if we can get the start_stack field from /proc/self/stat
1008 FILE *fp;
1009 int pid;
1010 char state;
1011 int ppid;
1012 int pgrp;
1013 int session;
1014 int nr;
1015 int tpgrp;
1016 unsigned long flags;
1017 unsigned long minflt;
1018 unsigned long cminflt;
1019 unsigned long majflt;
1020 unsigned long cmajflt;
1021 unsigned long utime;
1022 unsigned long stime;
1023 long cutime;
1024 long cstime;
1025 long prio;
1026 long nice;
1027 long junk;
1028 long it_real;
1029 uintptr_t start;
1030 uintptr_t vsize;
1031 intptr_t rss;
1032 uintptr_t rsslim;
1033 uintptr_t scodes;
1034 uintptr_t ecode;
1035 int i;
1036
1037 // Figure what the primordial thread stack base is. Code is inspired
1038 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1039 // followed by command name surrounded by parentheses, state, etc.
1040 char stat[2048];
1041 int statlen;
1042
1043 fp = fopen("/proc/self/stat", "r");
1044 if (fp) {
1045 statlen = fread(stat, 1, 2047, fp);
1046 stat[statlen] = '\0';
1047 fclose(fp);
1048
1049 // Skip pid and the command string. Note that we could be dealing with
1050 // weird command names, e.g. user could decide to rename java launcher
1051 // to "java 1.4.2 :)", then the stat file would look like
1052 // 1234 (java 1.4.2 :)) R ... ...
1053 // We don't really need to know the command string, just find the last
1054 // occurrence of ")" and then start parsing from there. See bug 4726580.
1055 char * s = strrchr(stat, ')');
1056
1057 i = 0;
1058 if (s) {
1059 // Skip blank chars
1060 do { s++; } while (s && isspace(*s));
1061
1062 #define _UFM UINTX_FORMAT
1063 #define _DFM INTX_FORMAT
1064
1065 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1066 // 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
1067 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,
1068 &state, // 3 %c
1069 &ppid, // 4 %d
1070 &pgrp, // 5 %d
1071 &session, // 6 %d
1072 &nr, // 7 %d
1073 &tpgrp, // 8 %d
1074 &flags, // 9 %lu
1075 &minflt, // 10 %lu
1076 &cminflt, // 11 %lu
1077 &majflt, // 12 %lu
1078 &cmajflt, // 13 %lu
1079 &utime, // 14 %lu
1080 &stime, // 15 %lu
1081 &cutime, // 16 %ld
1082 &cstime, // 17 %ld
1083 &prio, // 18 %ld
1084 &nice, // 19 %ld
1085 &junk, // 20 %ld
1086 &it_real, // 21 %ld
1087 &start, // 22 UINTX_FORMAT
1088 &vsize, // 23 UINTX_FORMAT
1089 &rss, // 24 INTX_FORMAT
1090 &rsslim, // 25 UINTX_FORMAT
1091 &scodes, // 26 UINTX_FORMAT
1092 &ecode, // 27 UINTX_FORMAT
1093 &stack_start); // 28 UINTX_FORMAT
1094 }
1095
1096 #undef _UFM
1097 #undef _DFM
1098
1099 if (i != 28 - 2) {
1100 assert(false, "Bad conversion from /proc/self/stat");
1101 // product mode - assume we are the initial thread, good luck in the
1102 // embedded case.
1103 warning("Can't detect initial thread stack location - bad conversion");
1104 stack_start = (uintptr_t) &rlim;
1105 }
1106 } else {
1107 // For some reason we can't open /proc/self/stat (for example, running on
1108 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1109 // most cases, so don't abort:
1110 warning("Can't detect initial thread stack location - no /proc/self/stat");
1111 stack_start = (uintptr_t) &rlim;
1112 }
1113 }
1114
1115 // Now we have a pointer (stack_start) very close to the stack top, the
1116 // next thing to do is to figure out the exact location of stack top. We
1117 // can find out the virtual memory area that contains stack_start by
1118 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1119 // and its upper limit is the real stack top. (again, this would fail if
1120 // running inside chroot, because /proc may not exist.)
1121
1122 uintptr_t stack_top;
1123 address low, high;
1124 if (find_vma((address)stack_start, &low, &high)) {
1125 // success, "high" is the true stack top. (ignore "low", because initial
1126 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1127 stack_top = (uintptr_t)high;
1128 } else {
1129 // failed, likely because /proc/self/maps does not exist
1130 warning("Can't detect initial thread stack location - find_vma failed");
1131 // best effort: stack_start is normally within a few pages below the real
1132 // stack top, use it as stack top, and reduce stack size so we won't put
1133 // guard page outside stack.
1134 stack_top = stack_start;
1135 stack_size -= 16 * page_size();
1136 }
1137
1138 // stack_top could be partially down the page so align it
1139 stack_top = align_size_up(stack_top, page_size());
1140
1141 if (max_size && stack_size > max_size) {
1142 _initial_thread_stack_size = max_size;
1143 } else {
1144 _initial_thread_stack_size = stack_size;
1145 }
1146
1147 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1148 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1149 }
1150
1151 ////////////////////////////////////////////////////////////////////////////////
1152 // time support
1153
1154 // Time since start-up in seconds to a fine granularity.
1155 // Used by VMSelfDestructTimer and the MemProfiler.
1156 double os::elapsedTime() {
1157
1158 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1159 }
1160
1161 jlong os::elapsed_counter() {
1162 return javaTimeNanos() - initial_time_count;
1163 }
1164
1165 jlong os::elapsed_frequency() {
1166 return NANOSECS_PER_SEC; // nanosecond resolution
1167 }
1168
1169 bool os::supports_vtime() { return true; }
1170 bool os::enable_vtime() { return false; }
1171 bool os::vtime_enabled() { return false; }
1172
1173 double os::elapsedVTime() {
1174 struct rusage usage;
1175 int retval = getrusage(RUSAGE_THREAD, &usage);
1176 if (retval == 0) {
1177 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);
1178 } else {
1179 // better than nothing, but not much
1180 return elapsedTime();
1181 }
1182 }
1183
1184 jlong os::javaTimeMillis() {
1185 timeval time;
1186 int status = gettimeofday(&time, NULL);
1187 assert(status != -1, "linux error");
1188 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1189 }
1190
1191 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1192 timeval time;
1193 int status = gettimeofday(&time, NULL);
1194 assert(status != -1, "linux error");
1195 seconds = jlong(time.tv_sec);
1196 nanos = jlong(time.tv_usec) * 1000;
1197 }
1198
1199
1200 #ifndef CLOCK_MONOTONIC
1201 #define CLOCK_MONOTONIC (1)
1202 #endif
1203
1204 void os::Linux::clock_init() {
1205 // we do dlopen's in this particular order due to bug in linux
1206 // dynamical loader (see 6348968) leading to crash on exit
1207 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1208 if (handle == NULL) {
1209 handle = dlopen("librt.so", RTLD_LAZY);
1210 }
1211
1212 if (handle) {
1213 int (*clock_getres_func)(clockid_t, struct timespec*) =
1214 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1215 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1216 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1217 if (clock_getres_func && clock_gettime_func) {
1218 // See if monotonic clock is supported by the kernel. Note that some
1219 // early implementations simply return kernel jiffies (updated every
1220 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1221 // for nano time (though the monotonic property is still nice to have).
1222 // It's fixed in newer kernels, however clock_getres() still returns
1223 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1224 // resolution for now. Hopefully as people move to new kernels, this
1225 // won't be a problem.
1226 struct timespec res;
1227 struct timespec tp;
1228 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1229 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1230 // yes, monotonic clock is supported
1231 _clock_gettime = clock_gettime_func;
1232 return;
1233 } else {
1234 // close librt if there is no monotonic clock
1235 dlclose(handle);
1236 }
1237 }
1238 }
1239 warning("No monotonic clock was available - timed services may " \
1240 "be adversely affected if the time-of-day clock changes");
1241 }
1242
1243 #ifndef SYS_clock_getres
1244 #if defined(IA32) || defined(AMD64)
1245 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1246 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1247 #else
1248 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1249 #define sys_clock_getres(x,y) -1
1250 #endif
1251 #else
1252 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1253 #endif
1254
1255 void os::Linux::fast_thread_clock_init() {
1256 if (!UseLinuxPosixThreadCPUClocks) {
1257 return;
1258 }
1259 clockid_t clockid;
1260 struct timespec tp;
1261 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1262 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1263
1264 // Switch to using fast clocks for thread cpu time if
1265 // the sys_clock_getres() returns 0 error code.
1266 // Note, that some kernels may support the current thread
1267 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1268 // returned by the pthread_getcpuclockid().
1269 // If the fast Posix clocks are supported then the sys_clock_getres()
1270 // must return at least tp.tv_sec == 0 which means a resolution
1271 // better than 1 sec. This is extra check for reliability.
1272
1273 if (pthread_getcpuclockid_func &&
1274 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1275 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1276 _supports_fast_thread_cpu_time = true;
1277 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1278 }
1279 }
1280
1281 jlong os::javaTimeNanos() {
1282 if (os::supports_monotonic_clock()) {
1283 struct timespec tp;
1284 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1285 assert(status == 0, "gettime error");
1286 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1287 return result;
1288 } else {
1289 timeval time;
1290 int status = gettimeofday(&time, NULL);
1291 assert(status != -1, "linux error");
1292 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1293 return 1000 * usecs;
1294 }
1295 }
1296
1297 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1298 if (os::supports_monotonic_clock()) {
1299 info_ptr->max_value = ALL_64_BITS;
1300
1301 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1302 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1303 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1304 } else {
1305 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1306 info_ptr->max_value = ALL_64_BITS;
1307
1308 // gettimeofday is a real time clock so it skips
1309 info_ptr->may_skip_backward = true;
1310 info_ptr->may_skip_forward = true;
1311 }
1312
1313 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1314 }
1315
1316 // Return the real, user, and system times in seconds from an
1317 // arbitrary fixed point in the past.
1318 bool os::getTimesSecs(double* process_real_time,
1319 double* process_user_time,
1320 double* process_system_time) {
1321 struct tms ticks;
1322 clock_t real_ticks = times(&ticks);
1323
1324 if (real_ticks == (clock_t) (-1)) {
1325 return false;
1326 } else {
1327 double ticks_per_second = (double) clock_tics_per_sec;
1328 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1329 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1330 *process_real_time = ((double) real_ticks) / ticks_per_second;
1331
1332 return true;
1333 }
1334 }
1335
1336
1337 char * os::local_time_string(char *buf, size_t buflen) {
1338 struct tm t;
1339 time_t long_time;
1340 time(&long_time);
1341 localtime_r(&long_time, &t);
1342 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1343 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1344 t.tm_hour, t.tm_min, t.tm_sec);
1345 return buf;
1346 }
1347
1348 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1349 return localtime_r(clock, res);
1350 }
1351
1352 ////////////////////////////////////////////////////////////////////////////////
1353 // runtime exit support
1354
1355 // Note: os::shutdown() might be called very early during initialization, or
1356 // called from signal handler. Before adding something to os::shutdown(), make
1357 // sure it is async-safe and can handle partially initialized VM.
1358 void os::shutdown() {
1359
1360 // allow PerfMemory to attempt cleanup of any persistent resources
1361 perfMemory_exit();
1362
1363 // needs to remove object in file system
1364 AttachListener::abort();
1365
1366 // flush buffered output, finish log files
1367 ostream_abort();
1368
1369 // Check for abort hook
1370 abort_hook_t abort_hook = Arguments::abort_hook();
1371 if (abort_hook != NULL) {
1372 abort_hook();
1373 }
1374
1375 }
1376
1377 // Note: os::abort() might be called very early during initialization, or
1378 // called from signal handler. Before adding something to os::abort(), make
1379 // sure it is async-safe and can handle partially initialized VM.
1380 void os::abort(bool dump_core, void* siginfo, const void* context) {
1381 os::shutdown();
1382 if (dump_core) {
1383 #ifndef PRODUCT
1384 fdStream out(defaultStream::output_fd());
1385 out.print_raw("Current thread is ");
1386 char buf[16];
1387 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1388 out.print_raw_cr(buf);
1389 out.print_raw_cr("Dumping core ...");
1390 #endif
1391 ::abort(); // dump core
1392 }
1393
1394 ::exit(1);
1395 }
1396
1397 // Die immediately, no exit hook, no abort hook, no cleanup.
1398 void os::die() {
1399 ::abort();
1400 }
1401
1402
1403 // This method is a copy of JDK's sysGetLastErrorString
1404 // from src/solaris/hpi/src/system_md.c
1405
1406 size_t os::lasterror(char *buf, size_t len) {
1407 if (errno == 0) return 0;
1408
1409 const char *s = os::strerror(errno);
1410 size_t n = ::strlen(s);
1411 if (n >= len) {
1412 n = len - 1;
1413 }
1414 ::strncpy(buf, s, n);
1415 buf[n] = '\0';
1416 return n;
1417 }
1418
1419 // thread_id is kernel thread id (similar to Solaris LWP id)
1420 intx os::current_thread_id() { return os::Linux::gettid(); }
1421 int os::current_process_id() {
1422 return ::getpid();
1423 }
1424
1425 // DLL functions
1426
1427 const char* os::dll_file_extension() { return ".so"; }
1428
1429 // This must be hard coded because it's the system's temporary
1430 // directory not the java application's temp directory, ala java.io.tmpdir.
1431 const char* os::get_temp_directory() { return "/tmp"; }
1432
1433 static bool file_exists(const char* filename) {
1434 struct stat statbuf;
1435 if (filename == NULL || strlen(filename) == 0) {
1436 return false;
1437 }
1438 return os::stat(filename, &statbuf) == 0;
1439 }
1440
1441 bool os::dll_build_name(char* buffer, size_t buflen,
1442 const char* pname, const char* fname) {
1443 bool retval = false;
1444 // Copied from libhpi
1445 const size_t pnamelen = pname ? strlen(pname) : 0;
1446
1447 // Return error on buffer overflow.
1448 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1449 return retval;
1450 }
1451
1452 if (pnamelen == 0) {
1453 snprintf(buffer, buflen, "lib%s.so", fname);
1454 retval = true;
1455 } else if (strchr(pname, *os::path_separator()) != NULL) {
1456 int n;
1457 char** pelements = split_path(pname, &n);
1458 if (pelements == NULL) {
1459 return false;
1460 }
1461 for (int i = 0; i < n; i++) {
1462 // Really shouldn't be NULL, but check can't hurt
1463 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1464 continue; // skip the empty path values
1465 }
1466 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1467 if (file_exists(buffer)) {
1468 retval = true;
1469 break;
1470 }
1471 }
1472 // release the storage
1473 for (int i = 0; i < n; i++) {
1474 if (pelements[i] != NULL) {
1475 FREE_C_HEAP_ARRAY(char, pelements[i]);
1476 }
1477 }
1478 if (pelements != NULL) {
1479 FREE_C_HEAP_ARRAY(char*, pelements);
1480 }
1481 } else {
1482 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1483 retval = true;
1484 }
1485 return retval;
1486 }
1487
1488 // check if addr is inside libjvm.so
1489 bool os::address_is_in_vm(address addr) {
1490 static address libjvm_base_addr;
1491 Dl_info dlinfo;
1492
1493 if (libjvm_base_addr == NULL) {
1494 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1495 libjvm_base_addr = (address)dlinfo.dli_fbase;
1496 }
1497 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1498 }
1499
1500 if (dladdr((void *)addr, &dlinfo) != 0) {
1501 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1502 }
1503
1504 return false;
1505 }
1506
1507 bool os::dll_address_to_function_name(address addr, char *buf,
1508 int buflen, int *offset,
1509 bool demangle) {
1510 // buf is not optional, but offset is optional
1511 assert(buf != NULL, "sanity check");
1512
1513 Dl_info dlinfo;
1514
1515 if (dladdr((void*)addr, &dlinfo) != 0) {
1516 // see if we have a matching symbol
1517 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1518 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1519 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1520 }
1521 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1522 return true;
1523 }
1524 // no matching symbol so try for just file info
1525 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1526 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1527 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1528 return true;
1529 }
1530 }
1531 }
1532
1533 buf[0] = '\0';
1534 if (offset != NULL) *offset = -1;
1535 return false;
1536 }
1537
1538 struct _address_to_library_name {
1539 address addr; // input : memory address
1540 size_t buflen; // size of fname
1541 char* fname; // output: library name
1542 address base; // library base addr
1543 };
1544
1545 static int address_to_library_name_callback(struct dl_phdr_info *info,
1546 size_t size, void *data) {
1547 int i;
1548 bool found = false;
1549 address libbase = NULL;
1550 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1551
1552 // iterate through all loadable segments
1553 for (i = 0; i < info->dlpi_phnum; i++) {
1554 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1555 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1556 // base address of a library is the lowest address of its loaded
1557 // segments.
1558 if (libbase == NULL || libbase > segbase) {
1559 libbase = segbase;
1560 }
1561 // see if 'addr' is within current segment
1562 if (segbase <= d->addr &&
1563 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1564 found = true;
1565 }
1566 }
1567 }
1568
1569 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1570 // so dll_address_to_library_name() can fall through to use dladdr() which
1571 // can figure out executable name from argv[0].
1572 if (found && info->dlpi_name && info->dlpi_name[0]) {
1573 d->base = libbase;
1574 if (d->fname) {
1575 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1576 }
1577 return 1;
1578 }
1579 return 0;
1580 }
1581
1582 bool os::dll_address_to_library_name(address addr, char* buf,
1583 int buflen, int* offset) {
1584 // buf is not optional, but offset is optional
1585 assert(buf != NULL, "sanity check");
1586
1587 Dl_info dlinfo;
1588 struct _address_to_library_name data;
1589
1590 // There is a bug in old glibc dladdr() implementation that it could resolve
1591 // to wrong library name if the .so file has a base address != NULL. Here
1592 // we iterate through the program headers of all loaded libraries to find
1593 // out which library 'addr' really belongs to. This workaround can be
1594 // removed once the minimum requirement for glibc is moved to 2.3.x.
1595 data.addr = addr;
1596 data.fname = buf;
1597 data.buflen = buflen;
1598 data.base = NULL;
1599 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1600
1601 if (rslt) {
1602 // buf already contains library name
1603 if (offset) *offset = addr - data.base;
1604 return true;
1605 }
1606 if (dladdr((void*)addr, &dlinfo) != 0) {
1607 if (dlinfo.dli_fname != NULL) {
1608 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1609 }
1610 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1611 *offset = addr - (address)dlinfo.dli_fbase;
1612 }
1613 return true;
1614 }
1615
1616 buf[0] = '\0';
1617 if (offset) *offset = -1;
1618 return false;
1619 }
1620
1621 // Loads .dll/.so and
1622 // in case of error it checks if .dll/.so was built for the
1623 // same architecture as Hotspot is running on
1624
1625
1626 // Remember the stack's state. The Linux dynamic linker will change
1627 // the stack to 'executable' at most once, so we must safepoint only once.
1628 bool os::Linux::_stack_is_executable = false;
1629
1630 // VM operation that loads a library. This is necessary if stack protection
1631 // of the Java stacks can be lost during loading the library. If we
1632 // do not stop the Java threads, they can stack overflow before the stacks
1633 // are protected again.
1634 class VM_LinuxDllLoad: public VM_Operation {
1635 private:
1636 const char *_filename;
1637 char *_ebuf;
1638 int _ebuflen;
1639 void *_lib;
1640 public:
1641 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1642 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1643 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1644 void doit() {
1645 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1646 os::Linux::_stack_is_executable = true;
1647 }
1648 void* loaded_library() { return _lib; }
1649 };
1650
1651 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1652 void * result = NULL;
1653 bool load_attempted = false;
1654
1655 // Check whether the library to load might change execution rights
1656 // of the stack. If they are changed, the protection of the stack
1657 // guard pages will be lost. We need a safepoint to fix this.
1658 //
1659 // See Linux man page execstack(8) for more info.
1660 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1661 ElfFile ef(filename);
1662 if (!ef.specifies_noexecstack()) {
1663 if (!is_init_completed()) {
1664 os::Linux::_stack_is_executable = true;
1665 // This is OK - No Java threads have been created yet, and hence no
1666 // stack guard pages to fix.
1667 //
1668 // This should happen only when you are building JDK7 using a very
1669 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1670 //
1671 // Dynamic loader will make all stacks executable after
1672 // this function returns, and will not do that again.
1673 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1674 } else {
1675 warning("You have loaded library %s which might have disabled stack guard. "
1676 "The VM will try to fix the stack guard now.\n"
1677 "It's highly recommended that you fix the library with "
1678 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1679 filename);
1680
1681 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1682 JavaThread *jt = JavaThread::current();
1683 if (jt->thread_state() != _thread_in_native) {
1684 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1685 // that requires ExecStack. Cannot enter safe point. Let's give up.
1686 warning("Unable to fix stack guard. Giving up.");
1687 } else {
1688 if (!LoadExecStackDllInVMThread) {
1689 // This is for the case where the DLL has an static
1690 // constructor function that executes JNI code. We cannot
1691 // load such DLLs in the VMThread.
1692 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1693 }
1694
1695 ThreadInVMfromNative tiv(jt);
1696 debug_only(VMNativeEntryWrapper vew;)
1697
1698 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1699 VMThread::execute(&op);
1700 if (LoadExecStackDllInVMThread) {
1701 result = op.loaded_library();
1702 }
1703 load_attempted = true;
1704 }
1705 }
1706 }
1707 }
1708
1709 if (!load_attempted) {
1710 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1711 }
1712
1713 if (result != NULL) {
1714 // Successful loading
1715 return result;
1716 }
1717
1718 Elf32_Ehdr elf_head;
1719 int diag_msg_max_length=ebuflen-strlen(ebuf);
1720 char* diag_msg_buf=ebuf+strlen(ebuf);
1721
1722 if (diag_msg_max_length==0) {
1723 // No more space in ebuf for additional diagnostics message
1724 return NULL;
1725 }
1726
1727
1728 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1729
1730 if (file_descriptor < 0) {
1731 // Can't open library, report dlerror() message
1732 return NULL;
1733 }
1734
1735 bool failed_to_read_elf_head=
1736 (sizeof(elf_head)!=
1737 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1738
1739 ::close(file_descriptor);
1740 if (failed_to_read_elf_head) {
1741 // file i/o error - report dlerror() msg
1742 return NULL;
1743 }
1744
1745 typedef struct {
1746 Elf32_Half code; // Actual value as defined in elf.h
1747 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1748 char elf_class; // 32 or 64 bit
1749 char endianess; // MSB or LSB
1750 char* name; // String representation
1751 } arch_t;
1752
1753 #ifndef EM_486
1754 #define EM_486 6 /* Intel 80486 */
1755 #endif
1756 #ifndef EM_AARCH64
1757 #define EM_AARCH64 183 /* ARM AARCH64 */
1758 #endif
1759
1760 static const arch_t arch_array[]={
1761 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1762 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1763 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1764 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1765 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1766 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1767 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1768 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1769 #if defined(VM_LITTLE_ENDIAN)
1770 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1771 #else
1772 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1773 #endif
1774 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1775 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1776 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1777 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1778 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1779 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1780 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1781 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1782 };
1783
1784 #if (defined IA32)
1785 static Elf32_Half running_arch_code=EM_386;
1786 #elif (defined AMD64)
1787 static Elf32_Half running_arch_code=EM_X86_64;
1788 #elif (defined IA64)
1789 static Elf32_Half running_arch_code=EM_IA_64;
1790 #elif (defined __sparc) && (defined _LP64)
1791 static Elf32_Half running_arch_code=EM_SPARCV9;
1792 #elif (defined __sparc) && (!defined _LP64)
1793 static Elf32_Half running_arch_code=EM_SPARC;
1794 #elif (defined __powerpc64__)
1795 static Elf32_Half running_arch_code=EM_PPC64;
1796 #elif (defined __powerpc__)
1797 static Elf32_Half running_arch_code=EM_PPC;
1798 #elif (defined ARM)
1799 static Elf32_Half running_arch_code=EM_ARM;
1800 #elif (defined S390)
1801 static Elf32_Half running_arch_code=EM_S390;
1802 #elif (defined ALPHA)
1803 static Elf32_Half running_arch_code=EM_ALPHA;
1804 #elif (defined MIPSEL)
1805 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1806 #elif (defined PARISC)
1807 static Elf32_Half running_arch_code=EM_PARISC;
1808 #elif (defined MIPS)
1809 static Elf32_Half running_arch_code=EM_MIPS;
1810 #elif (defined M68K)
1811 static Elf32_Half running_arch_code=EM_68K;
1812 #elif (defined AARCH64)
1813 static Elf32_Half running_arch_code=EM_AARCH64;
1814 #else
1815 #error Method os::dll_load requires that one of following is defined:\
1816 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64
1817 #endif
1818
1819 // Identify compatability class for VM's architecture and library's architecture
1820 // Obtain string descriptions for architectures
1821
1822 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1823 int running_arch_index=-1;
1824
1825 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1826 if (running_arch_code == arch_array[i].code) {
1827 running_arch_index = i;
1828 }
1829 if (lib_arch.code == arch_array[i].code) {
1830 lib_arch.compat_class = arch_array[i].compat_class;
1831 lib_arch.name = arch_array[i].name;
1832 }
1833 }
1834
1835 assert(running_arch_index != -1,
1836 "Didn't find running architecture code (running_arch_code) in arch_array");
1837 if (running_arch_index == -1) {
1838 // Even though running architecture detection failed
1839 // we may still continue with reporting dlerror() message
1840 return NULL;
1841 }
1842
1843 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1844 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1845 return NULL;
1846 }
1847
1848 #ifndef S390
1849 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1850 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1851 return NULL;
1852 }
1853 #endif // !S390
1854
1855 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1856 if (lib_arch.name!=NULL) {
1857 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1858 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1859 lib_arch.name, arch_array[running_arch_index].name);
1860 } else {
1861 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1862 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1863 lib_arch.code,
1864 arch_array[running_arch_index].name);
1865 }
1866 }
1867
1868 return NULL;
1869 }
1870
1871 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1872 int ebuflen) {
1873 void * result = ::dlopen(filename, RTLD_LAZY);
1874 if (result == NULL) {
1875 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1876 ebuf[ebuflen-1] = '\0';
1877 }
1878 return result;
1879 }
1880
1881 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1882 int ebuflen) {
1883 void * result = NULL;
1884 if (LoadExecStackDllInVMThread) {
1885 result = dlopen_helper(filename, ebuf, ebuflen);
1886 }
1887
1888 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1889 // library that requires an executable stack, or which does not have this
1890 // stack attribute set, dlopen changes the stack attribute to executable. The
1891 // read protection of the guard pages gets lost.
1892 //
1893 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1894 // may have been queued at the same time.
1895
1896 if (!_stack_is_executable) {
1897 JavaThread *jt = Threads::first();
1898
1899 while (jt) {
1900 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1901 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1902 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1903 warning("Attempt to reguard stack yellow zone failed.");
1904 }
1905 }
1906 jt = jt->next();
1907 }
1908 }
1909
1910 return result;
1911 }
1912
1913 void* os::dll_lookup(void* handle, const char* name) {
1914 void* res = dlsym(handle, name);
1915 return res;
1916 }
1917
1918 void* os::get_default_process_handle() {
1919 return (void*)::dlopen(NULL, RTLD_LAZY);
1920 }
1921
1922 static bool _print_ascii_file(const char* filename, outputStream* st) {
1923 int fd = ::open(filename, O_RDONLY);
1924 if (fd == -1) {
1925 return false;
1926 }
1927
1928 char buf[33];
1929 int bytes;
1930 buf[32] = '\0';
1931 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1932 st->print_raw(buf, bytes);
1933 }
1934
1935 ::close(fd);
1936
1937 return true;
1938 }
1939
1940 void os::print_dll_info(outputStream *st) {
1941 st->print_cr("Dynamic libraries:");
1942
1943 char fname[32];
1944 pid_t pid = os::Linux::gettid();
1945
1946 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1947
1948 if (!_print_ascii_file(fname, st)) {
1949 st->print("Can not get library information for pid = %d\n", pid);
1950 }
1951 }
1952
1953 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1954 FILE *procmapsFile = NULL;
1955
1956 // Open the procfs maps file for the current process
1957 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1958 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1959 char line[PATH_MAX + 100];
1960
1961 // Read line by line from 'file'
1962 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1963 u8 base, top, offset, inode;
1964 char permissions[5];
1965 char device[6];
1966 char name[PATH_MAX + 1];
1967
1968 // Parse fields from line
1969 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1970 &base, &top, permissions, &offset, device, &inode, name);
1971
1972 // Filter by device id '00:00' so that we only get file system mapped files.
1973 if (strcmp(device, "00:00") != 0) {
1974
1975 // Call callback with the fields of interest
1976 if(callback(name, (address)base, (address)top, param)) {
1977 // Oops abort, callback aborted
1978 fclose(procmapsFile);
1979 return 1;
1980 }
1981 }
1982 }
1983 fclose(procmapsFile);
1984 }
1985 return 0;
1986 }
1987
1988 void os::print_os_info_brief(outputStream* st) {
1989 os::Linux::print_distro_info(st);
1990
1991 os::Posix::print_uname_info(st);
1992
1993 os::Linux::print_libversion_info(st);
1994
1995 }
1996
1997 void os::print_os_info(outputStream* st) {
1998 st->print("OS:");
1999
2000 os::Linux::print_distro_info(st);
2001
2002 os::Posix::print_uname_info(st);
2003
2004 // Print warning if unsafe chroot environment detected
2005 if (unsafe_chroot_detected) {
2006 st->print("WARNING!! ");
2007 st->print_cr("%s", unstable_chroot_error);
2008 }
2009
2010 os::Linux::print_libversion_info(st);
2011
2012 os::Posix::print_rlimit_info(st);
2013
2014 os::Posix::print_load_average(st);
2015
2016 os::Linux::print_full_memory_info(st);
2017 }
2018
2019 // Try to identify popular distros.
2020 // Most Linux distributions have a /etc/XXX-release file, which contains
2021 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2022 // file that also contains the OS version string. Some have more than one
2023 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2024 // /etc/redhat-release.), so the order is important.
2025 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2026 // their own specific XXX-release file as well as a redhat-release file.
2027 // Because of this the XXX-release file needs to be searched for before the
2028 // redhat-release file.
2029 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2030 // search for redhat-release / SuSE-release needs to be before lsb-release.
2031 // Since the lsb-release file is the new standard it needs to be searched
2032 // before the older style release files.
2033 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2034 // next to last resort. The os-release file is a new standard that contains
2035 // distribution information and the system-release file seems to be an old
2036 // standard that has been replaced by the lsb-release and os-release files.
2037 // Searching for the debian_version file is the last resort. It contains
2038 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2039 // "Debian " is printed before the contents of the debian_version file.
2040
2041 const char* distro_files[] = {
2042 "/etc/oracle-release",
2043 "/etc/mandriva-release",
2044 "/etc/mandrake-release",
2045 "/etc/sun-release",
2046 "/etc/redhat-release",
2047 "/etc/SuSE-release",
2048 "/etc/lsb-release",
2049 "/etc/turbolinux-release",
2050 "/etc/gentoo-release",
2051 "/etc/ltib-release",
2052 "/etc/angstrom-version",
2053 "/etc/system-release",
2054 "/etc/os-release",
2055 NULL };
2056
2057 void os::Linux::print_distro_info(outputStream* st) {
2058 for (int i = 0;; i++) {
2059 const char* file = distro_files[i];
2060 if (file == NULL) {
2061 break; // done
2062 }
2063 // If file prints, we found it.
2064 if (_print_ascii_file(file, st)) {
2065 return;
2066 }
2067 }
2068
2069 if (file_exists("/etc/debian_version")) {
2070 st->print("Debian ");
2071 _print_ascii_file("/etc/debian_version", st);
2072 } else {
2073 st->print("Linux");
2074 }
2075 st->cr();
2076 }
2077
2078 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2079 char buf[256];
2080 while (fgets(buf, sizeof(buf), fp)) {
2081 // Edit out extra stuff in expected format
2082 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2083 char* ptr = strstr(buf, "\""); // the name is in quotes
2084 if (ptr != NULL) {
2085 ptr++; // go beyond first quote
2086 char* nl = strchr(ptr, '\"');
2087 if (nl != NULL) *nl = '\0';
2088 strncpy(distro, ptr, length);
2089 } else {
2090 ptr = strstr(buf, "=");
2091 ptr++; // go beyond equals then
2092 char* nl = strchr(ptr, '\n');
2093 if (nl != NULL) *nl = '\0';
2094 strncpy(distro, ptr, length);
2095 }
2096 return;
2097 } else if (get_first_line) {
2098 char* nl = strchr(buf, '\n');
2099 if (nl != NULL) *nl = '\0';
2100 strncpy(distro, buf, length);
2101 return;
2102 }
2103 }
2104 // print last line and close
2105 char* nl = strchr(buf, '\n');
2106 if (nl != NULL) *nl = '\0';
2107 strncpy(distro, buf, length);
2108 }
2109
2110 static void parse_os_info(char* distro, size_t length, const char* file) {
2111 FILE* fp = fopen(file, "r");
2112 if (fp != NULL) {
2113 // if suse format, print out first line
2114 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2115 parse_os_info_helper(fp, distro, length, get_first_line);
2116 fclose(fp);
2117 }
2118 }
2119
2120 void os::get_summary_os_info(char* buf, size_t buflen) {
2121 for (int i = 0;; i++) {
2122 const char* file = distro_files[i];
2123 if (file == NULL) {
2124 break; // ran out of distro_files
2125 }
2126 if (file_exists(file)) {
2127 parse_os_info(buf, buflen, file);
2128 return;
2129 }
2130 }
2131 // special case for debian
2132 if (file_exists("/etc/debian_version")) {
2133 strncpy(buf, "Debian ", buflen);
2134 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2135 } else {
2136 strncpy(buf, "Linux", buflen);
2137 }
2138 }
2139
2140 void os::Linux::print_libversion_info(outputStream* st) {
2141 // libc, pthread
2142 st->print("libc:");
2143 st->print("%s ", os::Linux::glibc_version());
2144 st->print("%s ", os::Linux::libpthread_version());
2145 st->cr();
2146 }
2147
2148 void os::Linux::print_full_memory_info(outputStream* st) {
2149 st->print("\n/proc/meminfo:\n");
2150 _print_ascii_file("/proc/meminfo", st);
2151 st->cr();
2152 }
2153
2154 void os::print_memory_info(outputStream* st) {
2155
2156 st->print("Memory:");
2157 st->print(" %dk page", os::vm_page_size()>>10);
2158
2159 // values in struct sysinfo are "unsigned long"
2160 struct sysinfo si;
2161 sysinfo(&si);
2162
2163 st->print(", physical " UINT64_FORMAT "k",
2164 os::physical_memory() >> 10);
2165 st->print("(" UINT64_FORMAT "k free)",
2166 os::available_memory() >> 10);
2167 st->print(", swap " UINT64_FORMAT "k",
2168 ((jlong)si.totalswap * si.mem_unit) >> 10);
2169 st->print("(" UINT64_FORMAT "k free)",
2170 ((jlong)si.freeswap * si.mem_unit) >> 10);
2171 st->cr();
2172 }
2173
2174 // Print the first "model name" line and the first "flags" line
2175 // that we find and nothing more. We assume "model name" comes
2176 // before "flags" so if we find a second "model name", then the
2177 // "flags" field is considered missing.
2178 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2179 #if defined(IA32) || defined(AMD64)
2180 // Other platforms have less repetitive cpuinfo files
2181 FILE *fp = fopen("/proc/cpuinfo", "r");
2182 if (fp) {
2183 while (!feof(fp)) {
2184 if (fgets(buf, buflen, fp)) {
2185 // Assume model name comes before flags
2186 bool model_name_printed = false;
2187 if (strstr(buf, "model name") != NULL) {
2188 if (!model_name_printed) {
2189 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2190 st->print_raw(buf);
2191 model_name_printed = true;
2192 } else {
2193 // model name printed but not flags? Odd, just return
2194 fclose(fp);
2195 return true;
2196 }
2197 }
2198 // print the flags line too
2199 if (strstr(buf, "flags") != NULL) {
2200 st->print_raw(buf);
2201 fclose(fp);
2202 return true;
2203 }
2204 }
2205 }
2206 fclose(fp);
2207 }
2208 #endif // x86 platforms
2209 return false;
2210 }
2211
2212 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2213 // Only print the model name if the platform provides this as a summary
2214 if (!print_model_name_and_flags(st, buf, buflen)) {
2215 st->print("\n/proc/cpuinfo:\n");
2216 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2217 st->print_cr(" <Not Available>");
2218 }
2219 }
2220 }
2221
2222 #if defined(AMD64) || defined(IA32) || defined(X32)
2223 const char* search_string = "model name";
2224 #elif defined(SPARC)
2225 const char* search_string = "cpu";
2226 #elif defined(PPC64)
2227 const char* search_string = "cpu";
2228 #else
2229 const char* search_string = "Processor";
2230 #endif
2231
2232 // Parses the cpuinfo file for string representing the model name.
2233 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2234 FILE* fp = fopen("/proc/cpuinfo", "r");
2235 if (fp != NULL) {
2236 while (!feof(fp)) {
2237 char buf[256];
2238 if (fgets(buf, sizeof(buf), fp)) {
2239 char* start = strstr(buf, search_string);
2240 if (start != NULL) {
2241 char *ptr = start + strlen(search_string);
2242 char *end = buf + strlen(buf);
2243 while (ptr != end) {
2244 // skip whitespace and colon for the rest of the name.
2245 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2246 break;
2247 }
2248 ptr++;
2249 }
2250 if (ptr != end) {
2251 // reasonable string, get rid of newline and keep the rest
2252 char* nl = strchr(buf, '\n');
2253 if (nl != NULL) *nl = '\0';
2254 strncpy(cpuinfo, ptr, length);
2255 fclose(fp);
2256 return;
2257 }
2258 }
2259 }
2260 }
2261 fclose(fp);
2262 }
2263 // cpuinfo not found or parsing failed, just print generic string. The entire
2264 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2265 #if defined(AMD64)
2266 strncpy(cpuinfo, "x86_64", length);
2267 #elif defined(IA32)
2268 strncpy(cpuinfo, "x86_32", length);
2269 #elif defined(IA64)
2270 strncpy(cpuinfo, "IA64", length);
2271 #elif defined(SPARC)
2272 strncpy(cpuinfo, "sparcv9", length);
2273 #elif defined(AARCH64)
2274 strncpy(cpuinfo, "AArch64", length);
2275 #elif defined(ARM)
2276 strncpy(cpuinfo, "ARM", length);
2277 #elif defined(PPC)
2278 strncpy(cpuinfo, "PPC64", length);
2279 #elif defined(ZERO_LIBARCH)
2280 strncpy(cpuinfo, ZERO_LIBARCH, length);
2281 #else
2282 strncpy(cpuinfo, "unknown", length);
2283 #endif
2284 }
2285
2286 static void print_signal_handler(outputStream* st, int sig,
2287 char* buf, size_t buflen);
2288
2289 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2290 st->print_cr("Signal Handlers:");
2291 print_signal_handler(st, SIGSEGV, buf, buflen);
2292 print_signal_handler(st, SIGBUS , buf, buflen);
2293 print_signal_handler(st, SIGFPE , buf, buflen);
2294 print_signal_handler(st, SIGPIPE, buf, buflen);
2295 print_signal_handler(st, SIGXFSZ, buf, buflen);
2296 print_signal_handler(st, SIGILL , buf, buflen);
2297 print_signal_handler(st, SR_signum, buf, buflen);
2298 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2299 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2300 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2301 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2302 #if defined(PPC64)
2303 print_signal_handler(st, SIGTRAP, buf, buflen);
2304 #endif
2305 }
2306
2307 static char saved_jvm_path[MAXPATHLEN] = {0};
2308
2309 // Find the full path to the current module, libjvm.so
2310 void os::jvm_path(char *buf, jint buflen) {
2311 // Error checking.
2312 if (buflen < MAXPATHLEN) {
2313 assert(false, "must use a large-enough buffer");
2314 buf[0] = '\0';
2315 return;
2316 }
2317 // Lazy resolve the path to current module.
2318 if (saved_jvm_path[0] != 0) {
2319 strcpy(buf, saved_jvm_path);
2320 return;
2321 }
2322
2323 char dli_fname[MAXPATHLEN];
2324 bool ret = dll_address_to_library_name(
2325 CAST_FROM_FN_PTR(address, os::jvm_path),
2326 dli_fname, sizeof(dli_fname), NULL);
2327 assert(ret, "cannot locate libjvm");
2328 char *rp = NULL;
2329 if (ret && dli_fname[0] != '\0') {
2330 rp = realpath(dli_fname, buf);
2331 }
2332 if (rp == NULL) {
2333 return;
2334 }
2335
2336 if (Arguments::sun_java_launcher_is_altjvm()) {
2337 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2338 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so".
2339 // If "/jre/lib/" appears at the right place in the string, then
2340 // assume we are installed in a JDK and we're done. Otherwise, check
2341 // for a JAVA_HOME environment variable and fix up the path so it
2342 // looks like libjvm.so is installed there (append a fake suffix
2343 // hotspot/libjvm.so).
2344 const char *p = buf + strlen(buf) - 1;
2345 for (int count = 0; p > buf && count < 5; ++count) {
2346 for (--p; p > buf && *p != '/'; --p)
2347 /* empty */ ;
2348 }
2349
2350 if (strncmp(p, "/jre/lib/", 9) != 0) {
2351 // Look for JAVA_HOME in the environment.
2352 char* java_home_var = ::getenv("JAVA_HOME");
2353 if (java_home_var != NULL && java_home_var[0] != 0) {
2354 char* jrelib_p;
2355 int len;
2356
2357 // Check the current module name "libjvm.so".
2358 p = strrchr(buf, '/');
2359 if (p == NULL) {
2360 return;
2361 }
2362 assert(strstr(p, "/libjvm") == p, "invalid library name");
2363
2364 rp = realpath(java_home_var, buf);
2365 if (rp == NULL) {
2366 return;
2367 }
2368
2369 // determine if this is a legacy image or modules image
2370 // modules image doesn't have "jre" subdirectory
2371 len = strlen(buf);
2372 assert(len < buflen, "Ran out of buffer room");
2373 jrelib_p = buf + len;
2374 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2375 if (0 != access(buf, F_OK)) {
2376 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2377 }
2378
2379 if (0 == access(buf, F_OK)) {
2380 // Use current module name "libjvm.so"
2381 len = strlen(buf);
2382 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2383 } else {
2384 // Go back to path of .so
2385 rp = realpath(dli_fname, buf);
2386 if (rp == NULL) {
2387 return;
2388 }
2389 }
2390 }
2391 }
2392 }
2393
2394 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2395 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2396 }
2397
2398 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2399 // no prefix required, not even "_"
2400 }
2401
2402 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2403 // no suffix required
2404 }
2405
2406 ////////////////////////////////////////////////////////////////////////////////
2407 // sun.misc.Signal support
2408
2409 static volatile jint sigint_count = 0;
2410
2411 static void UserHandler(int sig, void *siginfo, void *context) {
2412 // 4511530 - sem_post is serialized and handled by the manager thread. When
2413 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2414 // don't want to flood the manager thread with sem_post requests.
2415 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2416 return;
2417 }
2418
2419 // Ctrl-C is pressed during error reporting, likely because the error
2420 // handler fails to abort. Let VM die immediately.
2421 if (sig == SIGINT && is_error_reported()) {
2422 os::die();
2423 }
2424
2425 os::signal_notify(sig);
2426 }
2427
2428 void* os::user_handler() {
2429 return CAST_FROM_FN_PTR(void*, UserHandler);
2430 }
2431
2432 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2433 struct timespec ts;
2434 // Semaphore's are always associated with CLOCK_REALTIME
2435 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2436 // see unpackTime for discussion on overflow checking
2437 if (sec >= MAX_SECS) {
2438 ts.tv_sec += MAX_SECS;
2439 ts.tv_nsec = 0;
2440 } else {
2441 ts.tv_sec += sec;
2442 ts.tv_nsec += nsec;
2443 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2444 ts.tv_nsec -= NANOSECS_PER_SEC;
2445 ++ts.tv_sec; // note: this must be <= max_secs
2446 }
2447 }
2448
2449 return ts;
2450 }
2451
2452 extern "C" {
2453 typedef void (*sa_handler_t)(int);
2454 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2455 }
2456
2457 void* os::signal(int signal_number, void* handler) {
2458 struct sigaction sigAct, oldSigAct;
2459
2460 sigfillset(&(sigAct.sa_mask));
2461 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2462 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2463
2464 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2465 // -1 means registration failed
2466 return (void *)-1;
2467 }
2468
2469 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2470 }
2471
2472 void os::signal_raise(int signal_number) {
2473 ::raise(signal_number);
2474 }
2475
2476 // The following code is moved from os.cpp for making this
2477 // code platform specific, which it is by its very nature.
2478
2479 // Will be modified when max signal is changed to be dynamic
2480 int os::sigexitnum_pd() {
2481 return NSIG;
2482 }
2483
2484 // a counter for each possible signal value
2485 static volatile jint pending_signals[NSIG+1] = { 0 };
2486
2487 // Linux(POSIX) specific hand shaking semaphore.
2488 static sem_t sig_sem;
2489 static PosixSemaphore sr_semaphore;
2490
2491 void os::signal_init_pd() {
2492 // Initialize signal structures
2493 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2494
2495 // Initialize signal semaphore
2496 ::sem_init(&sig_sem, 0, 0);
2497 }
2498
2499 void os::signal_notify(int sig) {
2500 Atomic::inc(&pending_signals[sig]);
2501 ::sem_post(&sig_sem);
2502 }
2503
2504 static int check_pending_signals(bool wait) {
2505 Atomic::store(0, &sigint_count);
2506 for (;;) {
2507 for (int i = 0; i < NSIG + 1; i++) {
2508 jint n = pending_signals[i];
2509 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2510 return i;
2511 }
2512 }
2513 if (!wait) {
2514 return -1;
2515 }
2516 JavaThread *thread = JavaThread::current();
2517 ThreadBlockInVM tbivm(thread);
2518
2519 bool threadIsSuspended;
2520 do {
2521 thread->set_suspend_equivalent();
2522 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2523 ::sem_wait(&sig_sem);
2524
2525 // were we externally suspended while we were waiting?
2526 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2527 if (threadIsSuspended) {
2528 // The semaphore has been incremented, but while we were waiting
2529 // another thread suspended us. We don't want to continue running
2530 // while suspended because that would surprise the thread that
2531 // suspended us.
2532 ::sem_post(&sig_sem);
2533
2534 thread->java_suspend_self();
2535 }
2536 } while (threadIsSuspended);
2537 }
2538 }
2539
2540 int os::signal_lookup() {
2541 return check_pending_signals(false);
2542 }
2543
2544 int os::signal_wait() {
2545 return check_pending_signals(true);
2546 }
2547
2548 ////////////////////////////////////////////////////////////////////////////////
2549 // Virtual Memory
2550
2551 int os::vm_page_size() {
2552 // Seems redundant as all get out
2553 assert(os::Linux::page_size() != -1, "must call os::init");
2554 return os::Linux::page_size();
2555 }
2556
2557 // Solaris allocates memory by pages.
2558 int os::vm_allocation_granularity() {
2559 assert(os::Linux::page_size() != -1, "must call os::init");
2560 return os::Linux::page_size();
2561 }
2562
2563 // Rationale behind this function:
2564 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2565 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2566 // samples for JITted code. Here we create private executable mapping over the code cache
2567 // and then we can use standard (well, almost, as mapping can change) way to provide
2568 // info for the reporting script by storing timestamp and location of symbol
2569 void linux_wrap_code(char* base, size_t size) {
2570 static volatile jint cnt = 0;
2571
2572 if (!UseOprofile) {
2573 return;
2574 }
2575
2576 char buf[PATH_MAX+1];
2577 int num = Atomic::add(1, &cnt);
2578
2579 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2580 os::get_temp_directory(), os::current_process_id(), num);
2581 unlink(buf);
2582
2583 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2584
2585 if (fd != -1) {
2586 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2587 if (rv != (off_t)-1) {
2588 if (::write(fd, "", 1) == 1) {
2589 mmap(base, size,
2590 PROT_READ|PROT_WRITE|PROT_EXEC,
2591 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2592 }
2593 }
2594 ::close(fd);
2595 unlink(buf);
2596 }
2597 }
2598
2599 static bool recoverable_mmap_error(int err) {
2600 // See if the error is one we can let the caller handle. This
2601 // list of errno values comes from JBS-6843484. I can't find a
2602 // Linux man page that documents this specific set of errno
2603 // values so while this list currently matches Solaris, it may
2604 // change as we gain experience with this failure mode.
2605 switch (err) {
2606 case EBADF:
2607 case EINVAL:
2608 case ENOTSUP:
2609 // let the caller deal with these errors
2610 return true;
2611
2612 default:
2613 // Any remaining errors on this OS can cause our reserved mapping
2614 // to be lost. That can cause confusion where different data
2615 // structures think they have the same memory mapped. The worst
2616 // scenario is if both the VM and a library think they have the
2617 // same memory mapped.
2618 return false;
2619 }
2620 }
2621
2622 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2623 int err) {
2624 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2625 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2626 os::strerror(err), err);
2627 }
2628
2629 static void warn_fail_commit_memory(char* addr, size_t size,
2630 size_t alignment_hint, bool exec,
2631 int err) {
2632 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2633 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2634 alignment_hint, exec, os::strerror(err), err);
2635 }
2636
2637 // NOTE: Linux kernel does not really reserve the pages for us.
2638 // All it does is to check if there are enough free pages
2639 // left at the time of mmap(). This could be a potential
2640 // problem.
2641 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2642 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2643 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2644 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2645 if (res != (uintptr_t) MAP_FAILED) {
2646 if (UseNUMAInterleaving) {
2647 numa_make_global(addr, size);
2648 }
2649 return 0;
2650 }
2651
2652 int err = errno; // save errno from mmap() call above
2653
2654 if (!recoverable_mmap_error(err)) {
2655 warn_fail_commit_memory(addr, size, exec, err);
2656 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2657 }
2658
2659 return err;
2660 }
2661
2662 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2663 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2664 }
2665
2666 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2667 const char* mesg) {
2668 assert(mesg != NULL, "mesg must be specified");
2669 int err = os::Linux::commit_memory_impl(addr, size, exec);
2670 if (err != 0) {
2671 // the caller wants all commit errors to exit with the specified mesg:
2672 warn_fail_commit_memory(addr, size, exec, err);
2673 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2674 }
2675 }
2676
2677 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2678 #ifndef MAP_HUGETLB
2679 #define MAP_HUGETLB 0x40000
2680 #endif
2681
2682 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2683 #ifndef MADV_HUGEPAGE
2684 #define MADV_HUGEPAGE 14
2685 #endif
2686
2687 int os::Linux::commit_memory_impl(char* addr, size_t size,
2688 size_t alignment_hint, bool exec) {
2689 int err = os::Linux::commit_memory_impl(addr, size, exec);
2690 if (err == 0) {
2691 realign_memory(addr, size, alignment_hint);
2692 }
2693 return err;
2694 }
2695
2696 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2697 bool exec) {
2698 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2699 }
2700
2701 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2702 size_t alignment_hint, bool exec,
2703 const char* mesg) {
2704 assert(mesg != NULL, "mesg must be specified");
2705 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2706 if (err != 0) {
2707 // the caller wants all commit errors to exit with the specified mesg:
2708 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2709 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2710 }
2711 }
2712
2713 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2714 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2715 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2716 // be supported or the memory may already be backed by huge pages.
2717 ::madvise(addr, bytes, MADV_HUGEPAGE);
2718 }
2719 }
2720
2721 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2722 // This method works by doing an mmap over an existing mmaping and effectively discarding
2723 // the existing pages. However it won't work for SHM-based large pages that cannot be
2724 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2725 // small pages on top of the SHM segment. This method always works for small pages, so we
2726 // allow that in any case.
2727 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2728 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2729 }
2730 }
2731
2732 void os::numa_make_global(char *addr, size_t bytes) {
2733 Linux::numa_interleave_memory(addr, bytes);
2734 }
2735
2736 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2737 // bind policy to MPOL_PREFERRED for the current thread.
2738 #define USE_MPOL_PREFERRED 0
2739
2740 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2741 // To make NUMA and large pages more robust when both enabled, we need to ease
2742 // the requirements on where the memory should be allocated. MPOL_BIND is the
2743 // default policy and it will force memory to be allocated on the specified
2744 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2745 // the specified node, but will not force it. Using this policy will prevent
2746 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2747 // free large pages.
2748 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2749 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2750 }
2751
2752 bool os::numa_topology_changed() { return false; }
2753
2754 size_t os::numa_get_groups_num() {
2755 int max_node = Linux::numa_max_node();
2756 return max_node > 0 ? max_node + 1 : 1;
2757 }
2758
2759 int os::numa_get_group_id() {
2760 int cpu_id = Linux::sched_getcpu();
2761 if (cpu_id != -1) {
2762 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2763 if (lgrp_id != -1) {
2764 return lgrp_id;
2765 }
2766 }
2767 return 0;
2768 }
2769
2770 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2771 for (size_t i = 0; i < size; i++) {
2772 ids[i] = i;
2773 }
2774 return size;
2775 }
2776
2777 bool os::get_page_info(char *start, page_info* info) {
2778 return false;
2779 }
2780
2781 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2782 page_info* page_found) {
2783 return end;
2784 }
2785
2786
2787 int os::Linux::sched_getcpu_syscall(void) {
2788 unsigned int cpu = 0;
2789 int retval = -1;
2790
2791 #if defined(IA32)
2792 #ifndef SYS_getcpu
2793 #define SYS_getcpu 318
2794 #endif
2795 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2796 #elif defined(AMD64)
2797 // Unfortunately we have to bring all these macros here from vsyscall.h
2798 // to be able to compile on old linuxes.
2799 #define __NR_vgetcpu 2
2800 #define VSYSCALL_START (-10UL << 20)
2801 #define VSYSCALL_SIZE 1024
2802 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2803 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2804 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2805 retval = vgetcpu(&cpu, NULL, NULL);
2806 #endif
2807
2808 return (retval == -1) ? retval : cpu;
2809 }
2810
2811 // Something to do with the numa-aware allocator needs these symbols
2812 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2813 extern "C" JNIEXPORT void numa_error(char *where) { }
2814
2815
2816 // If we are running with libnuma version > 2, then we should
2817 // be trying to use symbols with versions 1.1
2818 // If we are running with earlier version, which did not have symbol versions,
2819 // we should use the base version.
2820 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2821 void *f = dlvsym(handle, name, "libnuma_1.1");
2822 if (f == NULL) {
2823 f = dlsym(handle, name);
2824 }
2825 return f;
2826 }
2827
2828 bool os::Linux::libnuma_init() {
2829 // sched_getcpu() should be in libc.
2830 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2831 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2832
2833 // If it's not, try a direct syscall.
2834 if (sched_getcpu() == -1) {
2835 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2836 (void*)&sched_getcpu_syscall));
2837 }
2838
2839 if (sched_getcpu() != -1) { // Does it work?
2840 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2841 if (handle != NULL) {
2842 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2843 libnuma_dlsym(handle, "numa_node_to_cpus")));
2844 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2845 libnuma_dlsym(handle, "numa_max_node")));
2846 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2847 libnuma_dlsym(handle, "numa_available")));
2848 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2849 libnuma_dlsym(handle, "numa_tonode_memory")));
2850 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2851 libnuma_dlsym(handle, "numa_interleave_memory")));
2852 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2853 libnuma_dlsym(handle, "numa_set_bind_policy")));
2854
2855
2856 if (numa_available() != -1) {
2857 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2858 // Create a cpu -> node mapping
2859 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2860 rebuild_cpu_to_node_map();
2861 return true;
2862 }
2863 }
2864 }
2865 return false;
2866 }
2867
2868 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2869 // The table is later used in get_node_by_cpu().
2870 void os::Linux::rebuild_cpu_to_node_map() {
2871 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2872 // in libnuma (possible values are starting from 16,
2873 // and continuing up with every other power of 2, but less
2874 // than the maximum number of CPUs supported by kernel), and
2875 // is a subject to change (in libnuma version 2 the requirements
2876 // are more reasonable) we'll just hardcode the number they use
2877 // in the library.
2878 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2879
2880 size_t cpu_num = os::active_processor_count();
2881 size_t cpu_map_size = NCPUS / BitsPerCLong;
2882 size_t cpu_map_valid_size =
2883 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2884
2885 cpu_to_node()->clear();
2886 cpu_to_node()->at_grow(cpu_num - 1);
2887 size_t node_num = numa_get_groups_num();
2888
2889 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2890 for (size_t i = 0; i < node_num; i++) {
2891 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2892 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2893 if (cpu_map[j] != 0) {
2894 for (size_t k = 0; k < BitsPerCLong; k++) {
2895 if (cpu_map[j] & (1UL << k)) {
2896 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2897 }
2898 }
2899 }
2900 }
2901 }
2902 }
2903 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2904 }
2905
2906 int os::Linux::get_node_by_cpu(int cpu_id) {
2907 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2908 return cpu_to_node()->at(cpu_id);
2909 }
2910 return -1;
2911 }
2912
2913 GrowableArray<int>* os::Linux::_cpu_to_node;
2914 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2915 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2916 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2917 os::Linux::numa_available_func_t os::Linux::_numa_available;
2918 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2919 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2920 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2921 unsigned long* os::Linux::_numa_all_nodes;
2922
2923 bool os::pd_uncommit_memory(char* addr, size_t size) {
2924 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2925 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2926 return res != (uintptr_t) MAP_FAILED;
2927 }
2928
2929 static address get_stack_commited_bottom(address bottom, size_t size) {
2930 address nbot = bottom;
2931 address ntop = bottom + size;
2932
2933 size_t page_sz = os::vm_page_size();
2934 unsigned pages = size / page_sz;
2935
2936 unsigned char vec[1];
2937 unsigned imin = 1, imax = pages + 1, imid;
2938 int mincore_return_value = 0;
2939
2940 assert(imin <= imax, "Unexpected page size");
2941
2942 while (imin < imax) {
2943 imid = (imax + imin) / 2;
2944 nbot = ntop - (imid * page_sz);
2945
2946 // Use a trick with mincore to check whether the page is mapped or not.
2947 // mincore sets vec to 1 if page resides in memory and to 0 if page
2948 // is swapped output but if page we are asking for is unmapped
2949 // it returns -1,ENOMEM
2950 mincore_return_value = mincore(nbot, page_sz, vec);
2951
2952 if (mincore_return_value == -1) {
2953 // Page is not mapped go up
2954 // to find first mapped page
2955 if (errno != EAGAIN) {
2956 assert(errno == ENOMEM, "Unexpected mincore errno");
2957 imax = imid;
2958 }
2959 } else {
2960 // Page is mapped go down
2961 // to find first not mapped page
2962 imin = imid + 1;
2963 }
2964 }
2965
2966 nbot = nbot + page_sz;
2967
2968 // Adjust stack bottom one page up if last checked page is not mapped
2969 if (mincore_return_value == -1) {
2970 nbot = nbot + page_sz;
2971 }
2972
2973 return nbot;
2974 }
2975
2976
2977 // Linux uses a growable mapping for the stack, and if the mapping for
2978 // the stack guard pages is not removed when we detach a thread the
2979 // stack cannot grow beyond the pages where the stack guard was
2980 // mapped. If at some point later in the process the stack expands to
2981 // that point, the Linux kernel cannot expand the stack any further
2982 // because the guard pages are in the way, and a segfault occurs.
2983 //
2984 // However, it's essential not to split the stack region by unmapping
2985 // a region (leaving a hole) that's already part of the stack mapping,
2986 // so if the stack mapping has already grown beyond the guard pages at
2987 // the time we create them, we have to truncate the stack mapping.
2988 // So, we need to know the extent of the stack mapping when
2989 // create_stack_guard_pages() is called.
2990
2991 // We only need this for stacks that are growable: at the time of
2992 // writing thread stacks don't use growable mappings (i.e. those
2993 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2994 // only applies to the main thread.
2995
2996 // If the (growable) stack mapping already extends beyond the point
2997 // where we're going to put our guard pages, truncate the mapping at
2998 // that point by munmap()ping it. This ensures that when we later
2999 // munmap() the guard pages we don't leave a hole in the stack
3000 // mapping. This only affects the main/initial thread
3001
3002 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3003 if (os::Linux::is_initial_thread()) {
3004 // As we manually grow stack up to bottom inside create_attached_thread(),
3005 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3006 // we don't need to do anything special.
3007 // Check it first, before calling heavy function.
3008 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3009 unsigned char vec[1];
3010
3011 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3012 // Fallback to slow path on all errors, including EAGAIN
3013 stack_extent = (uintptr_t) get_stack_commited_bottom(
3014 os::Linux::initial_thread_stack_bottom(),
3015 (size_t)addr - stack_extent);
3016 }
3017
3018 if (stack_extent < (uintptr_t)addr) {
3019 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3020 }
3021 }
3022
3023 return os::commit_memory(addr, size, !ExecMem);
3024 }
3025
3026 // If this is a growable mapping, remove the guard pages entirely by
3027 // munmap()ping them. If not, just call uncommit_memory(). This only
3028 // affects the main/initial thread, but guard against future OS changes
3029 // It's safe to always unmap guard pages for initial thread because we
3030 // always place it right after end of the mapped region
3031
3032 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3033 uintptr_t stack_extent, stack_base;
3034
3035 if (os::Linux::is_initial_thread()) {
3036 return ::munmap(addr, size) == 0;
3037 }
3038
3039 return os::uncommit_memory(addr, size);
3040 }
3041
3042 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3043 // at 'requested_addr'. If there are existing memory mappings at the same
3044 // location, however, they will be overwritten. If 'fixed' is false,
3045 // 'requested_addr' is only treated as a hint, the return value may or
3046 // may not start from the requested address. Unlike Linux mmap(), this
3047 // function returns NULL to indicate failure.
3048 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3049 char * addr;
3050 int flags;
3051
3052 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3053 if (fixed) {
3054 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3055 flags |= MAP_FIXED;
3056 }
3057
3058 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3059 // touch an uncommitted page. Otherwise, the read/write might
3060 // succeed if we have enough swap space to back the physical page.
3061 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3062 flags, -1, 0);
3063
3064 return addr == MAP_FAILED ? NULL : addr;
3065 }
3066
3067 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3068 // (req_addr != NULL) or with a given alignment.
3069 // - bytes shall be a multiple of alignment.
3070 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3071 // - alignment sets the alignment at which memory shall be allocated.
3072 // It must be a multiple of allocation granularity.
3073 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3074 // req_addr or NULL.
3075 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3076
3077 size_t extra_size = bytes;
3078 if (req_addr == NULL && alignment > 0) {
3079 extra_size += alignment;
3080 }
3081
3082 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3083 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3084 -1, 0);
3085 if (start == MAP_FAILED) {
3086 start = NULL;
3087 } else {
3088 if (req_addr != NULL) {
3089 if (start != req_addr) {
3090 ::munmap(start, extra_size);
3091 start = NULL;
3092 }
3093 } else {
3094 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3095 char* const end_aligned = start_aligned + bytes;
3096 char* const end = start + extra_size;
3097 if (start_aligned > start) {
3098 ::munmap(start, start_aligned - start);
3099 }
3100 if (end_aligned < end) {
3101 ::munmap(end_aligned, end - end_aligned);
3102 }
3103 start = start_aligned;
3104 }
3105 }
3106 return start;
3107 }
3108
3109 static int anon_munmap(char * addr, size_t size) {
3110 return ::munmap(addr, size) == 0;
3111 }
3112
3113 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3114 size_t alignment_hint) {
3115 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3116 }
3117
3118 bool os::pd_release_memory(char* addr, size_t size) {
3119 return anon_munmap(addr, size);
3120 }
3121
3122 static bool linux_mprotect(char* addr, size_t size, int prot) {
3123 // Linux wants the mprotect address argument to be page aligned.
3124 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3125
3126 // According to SUSv3, mprotect() should only be used with mappings
3127 // established by mmap(), and mmap() always maps whole pages. Unaligned
3128 // 'addr' likely indicates problem in the VM (e.g. trying to change
3129 // protection of malloc'ed or statically allocated memory). Check the
3130 // caller if you hit this assert.
3131 assert(addr == bottom, "sanity check");
3132
3133 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3134 return ::mprotect(bottom, size, prot) == 0;
3135 }
3136
3137 // Set protections specified
3138 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3139 bool is_committed) {
3140 unsigned int p = 0;
3141 switch (prot) {
3142 case MEM_PROT_NONE: p = PROT_NONE; break;
3143 case MEM_PROT_READ: p = PROT_READ; break;
3144 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3145 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3146 default:
3147 ShouldNotReachHere();
3148 }
3149 // is_committed is unused.
3150 return linux_mprotect(addr, bytes, p);
3151 }
3152
3153 bool os::guard_memory(char* addr, size_t size) {
3154 return linux_mprotect(addr, size, PROT_NONE);
3155 }
3156
3157 bool os::unguard_memory(char* addr, size_t size) {
3158 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3159 }
3160
3161 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3162 size_t page_size) {
3163 bool result = false;
3164 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3165 MAP_ANONYMOUS|MAP_PRIVATE,
3166 -1, 0);
3167 if (p != MAP_FAILED) {
3168 void *aligned_p = align_ptr_up(p, page_size);
3169
3170 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3171
3172 munmap(p, page_size * 2);
3173 }
3174
3175 if (warn && !result) {
3176 warning("TransparentHugePages is not supported by the operating system.");
3177 }
3178
3179 return result;
3180 }
3181
3182 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3183 bool result = false;
3184 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3185 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3186 -1, 0);
3187
3188 if (p != MAP_FAILED) {
3189 // We don't know if this really is a huge page or not.
3190 FILE *fp = fopen("/proc/self/maps", "r");
3191 if (fp) {
3192 while (!feof(fp)) {
3193 char chars[257];
3194 long x = 0;
3195 if (fgets(chars, sizeof(chars), fp)) {
3196 if (sscanf(chars, "%lx-%*x", &x) == 1
3197 && x == (long)p) {
3198 if (strstr (chars, "hugepage")) {
3199 result = true;
3200 break;
3201 }
3202 }
3203 }
3204 }
3205 fclose(fp);
3206 }
3207 munmap(p, page_size);
3208 }
3209
3210 if (warn && !result) {
3211 warning("HugeTLBFS is not supported by the operating system.");
3212 }
3213
3214 return result;
3215 }
3216
3217 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3218 //
3219 // From the coredump_filter documentation:
3220 //
3221 // - (bit 0) anonymous private memory
3222 // - (bit 1) anonymous shared memory
3223 // - (bit 2) file-backed private memory
3224 // - (bit 3) file-backed shared memory
3225 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3226 // effective only if the bit 2 is cleared)
3227 // - (bit 5) hugetlb private memory
3228 // - (bit 6) hugetlb shared memory
3229 //
3230 static void set_coredump_filter(void) {
3231 FILE *f;
3232 long cdm;
3233
3234 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3235 return;
3236 }
3237
3238 if (fscanf(f, "%lx", &cdm) != 1) {
3239 fclose(f);
3240 return;
3241 }
3242
3243 rewind(f);
3244
3245 if ((cdm & LARGEPAGES_BIT) == 0) {
3246 cdm |= LARGEPAGES_BIT;
3247 fprintf(f, "%#lx", cdm);
3248 }
3249
3250 fclose(f);
3251 }
3252
3253 // Large page support
3254
3255 static size_t _large_page_size = 0;
3256
3257 size_t os::Linux::find_large_page_size() {
3258 size_t large_page_size = 0;
3259
3260 // large_page_size on Linux is used to round up heap size. x86 uses either
3261 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3262 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3263 // page as large as 256M.
3264 //
3265 // Here we try to figure out page size by parsing /proc/meminfo and looking
3266 // for a line with the following format:
3267 // Hugepagesize: 2048 kB
3268 //
3269 // If we can't determine the value (e.g. /proc is not mounted, or the text
3270 // format has been changed), we'll use the largest page size supported by
3271 // the processor.
3272
3273 #ifndef ZERO
3274 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3275 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M);
3276 #endif // ZERO
3277
3278 FILE *fp = fopen("/proc/meminfo", "r");
3279 if (fp) {
3280 while (!feof(fp)) {
3281 int x = 0;
3282 char buf[16];
3283 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3284 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3285 large_page_size = x * K;
3286 break;
3287 }
3288 } else {
3289 // skip to next line
3290 for (;;) {
3291 int ch = fgetc(fp);
3292 if (ch == EOF || ch == (int)'\n') break;
3293 }
3294 }
3295 }
3296 fclose(fp);
3297 }
3298
3299 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3300 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3301 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3302 proper_unit_for_byte_size(large_page_size));
3303 }
3304
3305 return large_page_size;
3306 }
3307
3308 size_t os::Linux::setup_large_page_size() {
3309 _large_page_size = Linux::find_large_page_size();
3310 const size_t default_page_size = (size_t)Linux::page_size();
3311 if (_large_page_size > default_page_size) {
3312 _page_sizes[0] = _large_page_size;
3313 _page_sizes[1] = default_page_size;
3314 _page_sizes[2] = 0;
3315 }
3316
3317 return _large_page_size;
3318 }
3319
3320 bool os::Linux::setup_large_page_type(size_t page_size) {
3321 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3322 FLAG_IS_DEFAULT(UseSHM) &&
3323 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3324
3325 // The type of large pages has not been specified by the user.
3326
3327 // Try UseHugeTLBFS and then UseSHM.
3328 UseHugeTLBFS = UseSHM = true;
3329
3330 // Don't try UseTransparentHugePages since there are known
3331 // performance issues with it turned on. This might change in the future.
3332 UseTransparentHugePages = false;
3333 }
3334
3335 if (UseTransparentHugePages) {
3336 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3337 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3338 UseHugeTLBFS = false;
3339 UseSHM = false;
3340 return true;
3341 }
3342 UseTransparentHugePages = false;
3343 }
3344
3345 if (UseHugeTLBFS) {
3346 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3347 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3348 UseSHM = false;
3349 return true;
3350 }
3351 UseHugeTLBFS = false;
3352 }
3353
3354 return UseSHM;
3355 }
3356
3357 void os::large_page_init() {
3358 if (!UseLargePages &&
3359 !UseTransparentHugePages &&
3360 !UseHugeTLBFS &&
3361 !UseSHM) {
3362 // Not using large pages.
3363 return;
3364 }
3365
3366 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3367 // The user explicitly turned off large pages.
3368 // Ignore the rest of the large pages flags.
3369 UseTransparentHugePages = false;
3370 UseHugeTLBFS = false;
3371 UseSHM = false;
3372 return;
3373 }
3374
3375 size_t large_page_size = Linux::setup_large_page_size();
3376 UseLargePages = Linux::setup_large_page_type(large_page_size);
3377
3378 set_coredump_filter();
3379 }
3380
3381 #ifndef SHM_HUGETLB
3382 #define SHM_HUGETLB 04000
3383 #endif
3384
3385 #define shm_warning_format(format, ...) \
3386 do { \
3387 if (UseLargePages && \
3388 (!FLAG_IS_DEFAULT(UseLargePages) || \
3389 !FLAG_IS_DEFAULT(UseSHM) || \
3390 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3391 warning(format, __VA_ARGS__); \
3392 } \
3393 } while (0)
3394
3395 #define shm_warning(str) shm_warning_format("%s", str)
3396
3397 #define shm_warning_with_errno(str) \
3398 do { \
3399 int err = errno; \
3400 shm_warning_format(str " (error = %d)", err); \
3401 } while (0)
3402
3403 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3404 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3405
3406 if (!is_size_aligned(alignment, SHMLBA)) {
3407 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3408 return NULL;
3409 }
3410
3411 // To ensure that we get 'alignment' aligned memory from shmat,
3412 // we pre-reserve aligned virtual memory and then attach to that.
3413
3414 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3415 if (pre_reserved_addr == NULL) {
3416 // Couldn't pre-reserve aligned memory.
3417 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3418 return NULL;
3419 }
3420
3421 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3422 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3423
3424 if ((intptr_t)addr == -1) {
3425 int err = errno;
3426 shm_warning_with_errno("Failed to attach shared memory.");
3427
3428 assert(err != EACCES, "Unexpected error");
3429 assert(err != EIDRM, "Unexpected error");
3430 assert(err != EINVAL, "Unexpected error");
3431
3432 // Since we don't know if the kernel unmapped the pre-reserved memory area
3433 // we can't unmap it, since that would potentially unmap memory that was
3434 // mapped from other threads.
3435 return NULL;
3436 }
3437
3438 return addr;
3439 }
3440
3441 static char* shmat_at_address(int shmid, char* req_addr) {
3442 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3443 assert(false, "Requested address needs to be SHMLBA aligned");
3444 return NULL;
3445 }
3446
3447 char* addr = (char*)shmat(shmid, req_addr, 0);
3448
3449 if ((intptr_t)addr == -1) {
3450 shm_warning_with_errno("Failed to attach shared memory.");
3451 return NULL;
3452 }
3453
3454 return addr;
3455 }
3456
3457 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3458 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3459 if (req_addr != NULL) {
3460 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3461 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3462 return shmat_at_address(shmid, req_addr);
3463 }
3464
3465 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3466 // return large page size aligned memory addresses when req_addr == NULL.
3467 // However, if the alignment is larger than the large page size, we have
3468 // to manually ensure that the memory returned is 'alignment' aligned.
3469 if (alignment > os::large_page_size()) {
3470 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3471 return shmat_with_alignment(shmid, bytes, alignment);
3472 } else {
3473 return shmat_at_address(shmid, NULL);
3474 }
3475 }
3476
3477 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3478 char* req_addr, bool exec) {
3479 // "exec" is passed in but not used. Creating the shared image for
3480 // the code cache doesn't have an SHM_X executable permission to check.
3481 assert(UseLargePages && UseSHM, "only for SHM large pages");
3482 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3483 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3484
3485 if (!is_size_aligned(bytes, os::large_page_size())) {
3486 return NULL; // Fallback to small pages.
3487 }
3488
3489 // Create a large shared memory region to attach to based on size.
3490 // Currently, size is the total size of the heap.
3491 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3492 if (shmid == -1) {
3493 // Possible reasons for shmget failure:
3494 // 1. shmmax is too small for Java heap.
3495 // > check shmmax value: cat /proc/sys/kernel/shmmax
3496 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3497 // 2. not enough large page memory.
3498 // > check available large pages: cat /proc/meminfo
3499 // > increase amount of large pages:
3500 // echo new_value > /proc/sys/vm/nr_hugepages
3501 // Note 1: different Linux may use different name for this property,
3502 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3503 // Note 2: it's possible there's enough physical memory available but
3504 // they are so fragmented after a long run that they can't
3505 // coalesce into large pages. Try to reserve large pages when
3506 // the system is still "fresh".
3507 shm_warning_with_errno("Failed to reserve shared memory.");
3508 return NULL;
3509 }
3510
3511 // Attach to the region.
3512 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3513
3514 // Remove shmid. If shmat() is successful, the actual shared memory segment
3515 // will be deleted when it's detached by shmdt() or when the process
3516 // terminates. If shmat() is not successful this will remove the shared
3517 // segment immediately.
3518 shmctl(shmid, IPC_RMID, NULL);
3519
3520 return addr;
3521 }
3522
3523 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3524 int error) {
3525 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3526
3527 bool warn_on_failure = UseLargePages &&
3528 (!FLAG_IS_DEFAULT(UseLargePages) ||
3529 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3530 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3531
3532 if (warn_on_failure) {
3533 char msg[128];
3534 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3535 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3536 warning("%s", msg);
3537 }
3538 }
3539
3540 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3541 char* req_addr,
3542 bool exec) {
3543 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3544 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3545 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3546
3547 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3548 char* addr = (char*)::mmap(req_addr, bytes, prot,
3549 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3550 -1, 0);
3551
3552 if (addr == MAP_FAILED) {
3553 warn_on_large_pages_failure(req_addr, bytes, errno);
3554 return NULL;
3555 }
3556
3557 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3558
3559 return addr;
3560 }
3561
3562 // Reserve memory using mmap(MAP_HUGETLB).
3563 // - bytes shall be a multiple of alignment.
3564 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3565 // - alignment sets the alignment at which memory shall be allocated.
3566 // It must be a multiple of allocation granularity.
3567 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3568 // req_addr or NULL.
3569 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3570 size_t alignment,
3571 char* req_addr,
3572 bool exec) {
3573 size_t large_page_size = os::large_page_size();
3574 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3575
3576 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3577 assert(is_size_aligned(bytes, alignment), "Must be");
3578
3579 // First reserve - but not commit - the address range in small pages.
3580 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3581
3582 if (start == NULL) {
3583 return NULL;
3584 }
3585
3586 assert(is_ptr_aligned(start, alignment), "Must be");
3587
3588 char* end = start + bytes;
3589
3590 // Find the regions of the allocated chunk that can be promoted to large pages.
3591 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3592 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3593
3594 size_t lp_bytes = lp_end - lp_start;
3595
3596 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3597
3598 if (lp_bytes == 0) {
3599 // The mapped region doesn't even span the start and the end of a large page.
3600 // Fall back to allocate a non-special area.
3601 ::munmap(start, end - start);
3602 return NULL;
3603 }
3604
3605 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3606
3607 void* result;
3608
3609 // Commit small-paged leading area.
3610 if (start != lp_start) {
3611 result = ::mmap(start, lp_start - start, prot,
3612 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3613 -1, 0);
3614 if (result == MAP_FAILED) {
3615 ::munmap(lp_start, end - lp_start);
3616 return NULL;
3617 }
3618 }
3619
3620 // Commit large-paged area.
3621 result = ::mmap(lp_start, lp_bytes, prot,
3622 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3623 -1, 0);
3624 if (result == MAP_FAILED) {
3625 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3626 // If the mmap above fails, the large pages region will be unmapped and we
3627 // have regions before and after with small pages. Release these regions.
3628 //
3629 // | mapped | unmapped | mapped |
3630 // ^ ^ ^ ^
3631 // start lp_start lp_end end
3632 //
3633 ::munmap(start, lp_start - start);
3634 ::munmap(lp_end, end - lp_end);
3635 return NULL;
3636 }
3637
3638 // Commit small-paged trailing area.
3639 if (lp_end != end) {
3640 result = ::mmap(lp_end, end - lp_end, prot,
3641 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3642 -1, 0);
3643 if (result == MAP_FAILED) {
3644 ::munmap(start, lp_end - start);
3645 return NULL;
3646 }
3647 }
3648
3649 return start;
3650 }
3651
3652 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3653 size_t alignment,
3654 char* req_addr,
3655 bool exec) {
3656 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3657 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3658 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3659 assert(is_power_of_2(os::large_page_size()), "Must be");
3660 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3661
3662 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3663 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3664 } else {
3665 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3666 }
3667 }
3668
3669 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3670 char* req_addr, bool exec) {
3671 assert(UseLargePages, "only for large pages");
3672
3673 char* addr;
3674 if (UseSHM) {
3675 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3676 } else {
3677 assert(UseHugeTLBFS, "must be");
3678 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3679 }
3680
3681 if (addr != NULL) {
3682 if (UseNUMAInterleaving) {
3683 numa_make_global(addr, bytes);
3684 }
3685
3686 // The memory is committed
3687 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3688 }
3689
3690 return addr;
3691 }
3692
3693 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3694 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3695 return shmdt(base) == 0;
3696 }
3697
3698 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3699 return pd_release_memory(base, bytes);
3700 }
3701
3702 bool os::release_memory_special(char* base, size_t bytes) {
3703 bool res;
3704 if (MemTracker::tracking_level() > NMT_minimal) {
3705 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3706 res = os::Linux::release_memory_special_impl(base, bytes);
3707 if (res) {
3708 tkr.record((address)base, bytes);
3709 }
3710
3711 } else {
3712 res = os::Linux::release_memory_special_impl(base, bytes);
3713 }
3714 return res;
3715 }
3716
3717 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3718 assert(UseLargePages, "only for large pages");
3719 bool res;
3720
3721 if (UseSHM) {
3722 res = os::Linux::release_memory_special_shm(base, bytes);
3723 } else {
3724 assert(UseHugeTLBFS, "must be");
3725 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3726 }
3727 return res;
3728 }
3729
3730 size_t os::large_page_size() {
3731 return _large_page_size;
3732 }
3733
3734 // With SysV SHM the entire memory region must be allocated as shared
3735 // memory.
3736 // HugeTLBFS allows application to commit large page memory on demand.
3737 // However, when committing memory with HugeTLBFS fails, the region
3738 // that was supposed to be committed will lose the old reservation
3739 // and allow other threads to steal that memory region. Because of this
3740 // behavior we can't commit HugeTLBFS memory.
3741 bool os::can_commit_large_page_memory() {
3742 return UseTransparentHugePages;
3743 }
3744
3745 bool os::can_execute_large_page_memory() {
3746 return UseTransparentHugePages || UseHugeTLBFS;
3747 }
3748
3749 // Reserve memory at an arbitrary address, only if that area is
3750 // available (and not reserved for something else).
3751
3752 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3753 const int max_tries = 10;
3754 char* base[max_tries];
3755 size_t size[max_tries];
3756 const size_t gap = 0x000000;
3757
3758 // Assert only that the size is a multiple of the page size, since
3759 // that's all that mmap requires, and since that's all we really know
3760 // about at this low abstraction level. If we need higher alignment,
3761 // we can either pass an alignment to this method or verify alignment
3762 // in one of the methods further up the call chain. See bug 5044738.
3763 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3764
3765 // Repeatedly allocate blocks until the block is allocated at the
3766 // right spot.
3767
3768 // Linux mmap allows caller to pass an address as hint; give it a try first,
3769 // if kernel honors the hint then we can return immediately.
3770 char * addr = anon_mmap(requested_addr, bytes, false);
3771 if (addr == requested_addr) {
3772 return requested_addr;
3773 }
3774
3775 if (addr != NULL) {
3776 // mmap() is successful but it fails to reserve at the requested address
3777 anon_munmap(addr, bytes);
3778 }
3779
3780 int i;
3781 for (i = 0; i < max_tries; ++i) {
3782 base[i] = reserve_memory(bytes);
3783
3784 if (base[i] != NULL) {
3785 // Is this the block we wanted?
3786 if (base[i] == requested_addr) {
3787 size[i] = bytes;
3788 break;
3789 }
3790
3791 // Does this overlap the block we wanted? Give back the overlapped
3792 // parts and try again.
3793
3794 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3795 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3796 unmap_memory(base[i], top_overlap);
3797 base[i] += top_overlap;
3798 size[i] = bytes - top_overlap;
3799 } else {
3800 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3801 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3802 unmap_memory(requested_addr, bottom_overlap);
3803 size[i] = bytes - bottom_overlap;
3804 } else {
3805 size[i] = bytes;
3806 }
3807 }
3808 }
3809 }
3810
3811 // Give back the unused reserved pieces.
3812
3813 for (int j = 0; j < i; ++j) {
3814 if (base[j] != NULL) {
3815 unmap_memory(base[j], size[j]);
3816 }
3817 }
3818
3819 if (i < max_tries) {
3820 return requested_addr;
3821 } else {
3822 return NULL;
3823 }
3824 }
3825
3826 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3827 return ::read(fd, buf, nBytes);
3828 }
3829
3830 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3831 return ::pread(fd, buf, nBytes, offset);
3832 }
3833
3834 // Short sleep, direct OS call.
3835 //
3836 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3837 // sched_yield(2) will actually give up the CPU:
3838 //
3839 // * Alone on this pariticular CPU, keeps running.
3840 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3841 // (pre 2.6.39).
3842 //
3843 // So calling this with 0 is an alternative.
3844 //
3845 void os::naked_short_sleep(jlong ms) {
3846 struct timespec req;
3847
3848 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3849 req.tv_sec = 0;
3850 if (ms > 0) {
3851 req.tv_nsec = (ms % 1000) * 1000000;
3852 } else {
3853 req.tv_nsec = 1;
3854 }
3855
3856 nanosleep(&req, NULL);
3857
3858 return;
3859 }
3860
3861 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3862 void os::infinite_sleep() {
3863 while (true) { // sleep forever ...
3864 ::sleep(100); // ... 100 seconds at a time
3865 }
3866 }
3867
3868 // Used to convert frequent JVM_Yield() to nops
3869 bool os::dont_yield() {
3870 return DontYieldALot;
3871 }
3872
3873 void os::naked_yield() {
3874 sched_yield();
3875 }
3876
3877 ////////////////////////////////////////////////////////////////////////////////
3878 // thread priority support
3879
3880 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3881 // only supports dynamic priority, static priority must be zero. For real-time
3882 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3883 // However, for large multi-threaded applications, SCHED_RR is not only slower
3884 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3885 // of 5 runs - Sep 2005).
3886 //
3887 // The following code actually changes the niceness of kernel-thread/LWP. It
3888 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3889 // not the entire user process, and user level threads are 1:1 mapped to kernel
3890 // threads. It has always been the case, but could change in the future. For
3891 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3892 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3893
3894 int os::java_to_os_priority[CriticalPriority + 1] = {
3895 19, // 0 Entry should never be used
3896
3897 4, // 1 MinPriority
3898 3, // 2
3899 2, // 3
3900
3901 1, // 4
3902 0, // 5 NormPriority
3903 -1, // 6
3904
3905 -2, // 7
3906 -3, // 8
3907 -4, // 9 NearMaxPriority
3908
3909 -5, // 10 MaxPriority
3910
3911 -5 // 11 CriticalPriority
3912 };
3913
3914 static int prio_init() {
3915 if (ThreadPriorityPolicy == 1) {
3916 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3917 // if effective uid is not root. Perhaps, a more elegant way of doing
3918 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3919 if (geteuid() != 0) {
3920 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3921 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3922 }
3923 ThreadPriorityPolicy = 0;
3924 }
3925 }
3926 if (UseCriticalJavaThreadPriority) {
3927 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3928 }
3929 return 0;
3930 }
3931
3932 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3933 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3934
3935 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3936 return (ret == 0) ? OS_OK : OS_ERR;
3937 }
3938
3939 OSReturn os::get_native_priority(const Thread* const thread,
3940 int *priority_ptr) {
3941 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3942 *priority_ptr = java_to_os_priority[NormPriority];
3943 return OS_OK;
3944 }
3945
3946 errno = 0;
3947 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3948 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3949 }
3950
3951 // Hint to the underlying OS that a task switch would not be good.
3952 // Void return because it's a hint and can fail.
3953 void os::hint_no_preempt() {}
3954
3955 ////////////////////////////////////////////////////////////////////////////////
3956 // suspend/resume support
3957
3958 // the low-level signal-based suspend/resume support is a remnant from the
3959 // old VM-suspension that used to be for java-suspension, safepoints etc,
3960 // within hotspot. Now there is a single use-case for this:
3961 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3962 // that runs in the watcher thread.
3963 // The remaining code is greatly simplified from the more general suspension
3964 // code that used to be used.
3965 //
3966 // The protocol is quite simple:
3967 // - suspend:
3968 // - sends a signal to the target thread
3969 // - polls the suspend state of the osthread using a yield loop
3970 // - target thread signal handler (SR_handler) sets suspend state
3971 // and blocks in sigsuspend until continued
3972 // - resume:
3973 // - sets target osthread state to continue
3974 // - sends signal to end the sigsuspend loop in the SR_handler
3975 //
3976 // Note that the SR_lock plays no role in this suspend/resume protocol.
3977
3978 static void resume_clear_context(OSThread *osthread) {
3979 osthread->set_ucontext(NULL);
3980 osthread->set_siginfo(NULL);
3981 }
3982
3983 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
3984 ucontext_t* context) {
3985 osthread->set_ucontext(context);
3986 osthread->set_siginfo(siginfo);
3987 }
3988
3989 // Handler function invoked when a thread's execution is suspended or
3990 // resumed. We have to be careful that only async-safe functions are
3991 // called here (Note: most pthread functions are not async safe and
3992 // should be avoided.)
3993 //
3994 // Note: sigwait() is a more natural fit than sigsuspend() from an
3995 // interface point of view, but sigwait() prevents the signal hander
3996 // from being run. libpthread would get very confused by not having
3997 // its signal handlers run and prevents sigwait()'s use with the
3998 // mutex granting granting signal.
3999 //
4000 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4001 //
4002 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4003 // Save and restore errno to avoid confusing native code with EINTR
4004 // after sigsuspend.
4005 int old_errno = errno;
4006
4007 Thread* thread = Thread::current_or_null_safe();
4008 assert(thread != NULL, "Missing current thread in SR_handler");
4009 OSThread* osthread = thread->osthread();
4010 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4011
4012 os::SuspendResume::State current = osthread->sr.state();
4013 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4014 suspend_save_context(osthread, siginfo, context);
4015
4016 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4017 os::SuspendResume::State state = osthread->sr.suspended();
4018 if (state == os::SuspendResume::SR_SUSPENDED) {
4019 sigset_t suspend_set; // signals for sigsuspend()
4020 sigemptyset(&suspend_set);
4021 // get current set of blocked signals and unblock resume signal
4022 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4023 sigdelset(&suspend_set, SR_signum);
4024
4025 sr_semaphore.signal();
4026 // wait here until we are resumed
4027 while (1) {
4028 sigsuspend(&suspend_set);
4029
4030 os::SuspendResume::State result = osthread->sr.running();
4031 if (result == os::SuspendResume::SR_RUNNING) {
4032 sr_semaphore.signal();
4033 break;
4034 }
4035 }
4036
4037 } else if (state == os::SuspendResume::SR_RUNNING) {
4038 // request was cancelled, continue
4039 } else {
4040 ShouldNotReachHere();
4041 }
4042
4043 resume_clear_context(osthread);
4044 } else if (current == os::SuspendResume::SR_RUNNING) {
4045 // request was cancelled, continue
4046 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4047 // ignore
4048 } else {
4049 // ignore
4050 }
4051
4052 errno = old_errno;
4053 }
4054
4055 static int SR_initialize() {
4056 struct sigaction act;
4057 char *s;
4058
4059 // Get signal number to use for suspend/resume
4060 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4061 int sig = ::strtol(s, 0, 10);
4062 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4063 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4064 SR_signum = sig;
4065 } else {
4066 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4067 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4068 }
4069 }
4070
4071 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4072 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4073
4074 sigemptyset(&SR_sigset);
4075 sigaddset(&SR_sigset, SR_signum);
4076
4077 // Set up signal handler for suspend/resume
4078 act.sa_flags = SA_RESTART|SA_SIGINFO;
4079 act.sa_handler = (void (*)(int)) SR_handler;
4080
4081 // SR_signum is blocked by default.
4082 // 4528190 - We also need to block pthread restart signal (32 on all
4083 // supported Linux platforms). Note that LinuxThreads need to block
4084 // this signal for all threads to work properly. So we don't have
4085 // to use hard-coded signal number when setting up the mask.
4086 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4087
4088 if (sigaction(SR_signum, &act, 0) == -1) {
4089 return -1;
4090 }
4091
4092 // Save signal flag
4093 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4094 return 0;
4095 }
4096
4097 static int sr_notify(OSThread* osthread) {
4098 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4099 assert_status(status == 0, status, "pthread_kill");
4100 return status;
4101 }
4102
4103 // "Randomly" selected value for how long we want to spin
4104 // before bailing out on suspending a thread, also how often
4105 // we send a signal to a thread we want to resume
4106 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4107 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4108
4109 // returns true on success and false on error - really an error is fatal
4110 // but this seems the normal response to library errors
4111 static bool do_suspend(OSThread* osthread) {
4112 assert(osthread->sr.is_running(), "thread should be running");
4113 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4114
4115 // mark as suspended and send signal
4116 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4117 // failed to switch, state wasn't running?
4118 ShouldNotReachHere();
4119 return false;
4120 }
4121
4122 if (sr_notify(osthread) != 0) {
4123 ShouldNotReachHere();
4124 }
4125
4126 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4127 while (true) {
4128 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4129 break;
4130 } else {
4131 // timeout
4132 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4133 if (cancelled == os::SuspendResume::SR_RUNNING) {
4134 return false;
4135 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4136 // make sure that we consume the signal on the semaphore as well
4137 sr_semaphore.wait();
4138 break;
4139 } else {
4140 ShouldNotReachHere();
4141 return false;
4142 }
4143 }
4144 }
4145
4146 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4147 return true;
4148 }
4149
4150 static void do_resume(OSThread* osthread) {
4151 assert(osthread->sr.is_suspended(), "thread should be suspended");
4152 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4153
4154 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4155 // failed to switch to WAKEUP_REQUEST
4156 ShouldNotReachHere();
4157 return;
4158 }
4159
4160 while (true) {
4161 if (sr_notify(osthread) == 0) {
4162 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4163 if (osthread->sr.is_running()) {
4164 return;
4165 }
4166 }
4167 } else {
4168 ShouldNotReachHere();
4169 }
4170 }
4171
4172 guarantee(osthread->sr.is_running(), "Must be running!");
4173 }
4174
4175 ///////////////////////////////////////////////////////////////////////////////////
4176 // signal handling (except suspend/resume)
4177
4178 // This routine may be used by user applications as a "hook" to catch signals.
4179 // The user-defined signal handler must pass unrecognized signals to this
4180 // routine, and if it returns true (non-zero), then the signal handler must
4181 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4182 // routine will never retun false (zero), but instead will execute a VM panic
4183 // routine kill the process.
4184 //
4185 // If this routine returns false, it is OK to call it again. This allows
4186 // the user-defined signal handler to perform checks either before or after
4187 // the VM performs its own checks. Naturally, the user code would be making
4188 // a serious error if it tried to handle an exception (such as a null check
4189 // or breakpoint) that the VM was generating for its own correct operation.
4190 //
4191 // This routine may recognize any of the following kinds of signals:
4192 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4193 // It should be consulted by handlers for any of those signals.
4194 //
4195 // The caller of this routine must pass in the three arguments supplied
4196 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4197 // field of the structure passed to sigaction(). This routine assumes that
4198 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4199 //
4200 // Note that the VM will print warnings if it detects conflicting signal
4201 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4202 //
4203 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4204 siginfo_t* siginfo,
4205 void* ucontext,
4206 int abort_if_unrecognized);
4207
4208 void signalHandler(int sig, siginfo_t* info, void* uc) {
4209 assert(info != NULL && uc != NULL, "it must be old kernel");
4210 int orig_errno = errno; // Preserve errno value over signal handler.
4211 JVM_handle_linux_signal(sig, info, uc, true);
4212 errno = orig_errno;
4213 }
4214
4215
4216 // This boolean allows users to forward their own non-matching signals
4217 // to JVM_handle_linux_signal, harmlessly.
4218 bool os::Linux::signal_handlers_are_installed = false;
4219
4220 // For signal-chaining
4221 struct sigaction sigact[NSIG];
4222 uint64_t sigs = 0;
4223 #if (64 < NSIG-1)
4224 #error "Not all signals can be encoded in sigs. Adapt its type!"
4225 #endif
4226 bool os::Linux::libjsig_is_loaded = false;
4227 typedef struct sigaction *(*get_signal_t)(int);
4228 get_signal_t os::Linux::get_signal_action = NULL;
4229
4230 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4231 struct sigaction *actp = NULL;
4232
4233 if (libjsig_is_loaded) {
4234 // Retrieve the old signal handler from libjsig
4235 actp = (*get_signal_action)(sig);
4236 }
4237 if (actp == NULL) {
4238 // Retrieve the preinstalled signal handler from jvm
4239 actp = get_preinstalled_handler(sig);
4240 }
4241
4242 return actp;
4243 }
4244
4245 static bool call_chained_handler(struct sigaction *actp, int sig,
4246 siginfo_t *siginfo, void *context) {
4247 // Call the old signal handler
4248 if (actp->sa_handler == SIG_DFL) {
4249 // It's more reasonable to let jvm treat it as an unexpected exception
4250 // instead of taking the default action.
4251 return false;
4252 } else if (actp->sa_handler != SIG_IGN) {
4253 if ((actp->sa_flags & SA_NODEFER) == 0) {
4254 // automaticlly block the signal
4255 sigaddset(&(actp->sa_mask), sig);
4256 }
4257
4258 sa_handler_t hand = NULL;
4259 sa_sigaction_t sa = NULL;
4260 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4261 // retrieve the chained handler
4262 if (siginfo_flag_set) {
4263 sa = actp->sa_sigaction;
4264 } else {
4265 hand = actp->sa_handler;
4266 }
4267
4268 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4269 actp->sa_handler = SIG_DFL;
4270 }
4271
4272 // try to honor the signal mask
4273 sigset_t oset;
4274 sigemptyset(&oset);
4275 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4276
4277 // call into the chained handler
4278 if (siginfo_flag_set) {
4279 (*sa)(sig, siginfo, context);
4280 } else {
4281 (*hand)(sig);
4282 }
4283
4284 // restore the signal mask
4285 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4286 }
4287 // Tell jvm's signal handler the signal is taken care of.
4288 return true;
4289 }
4290
4291 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4292 bool chained = false;
4293 // signal-chaining
4294 if (UseSignalChaining) {
4295 struct sigaction *actp = get_chained_signal_action(sig);
4296 if (actp != NULL) {
4297 chained = call_chained_handler(actp, sig, siginfo, context);
4298 }
4299 }
4300 return chained;
4301 }
4302
4303 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4304 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4305 return &sigact[sig];
4306 }
4307 return NULL;
4308 }
4309
4310 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4311 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4312 sigact[sig] = oldAct;
4313 sigs |= (uint64_t)1 << (sig-1);
4314 }
4315
4316 // for diagnostic
4317 int sigflags[NSIG];
4318
4319 int os::Linux::get_our_sigflags(int sig) {
4320 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4321 return sigflags[sig];
4322 }
4323
4324 void os::Linux::set_our_sigflags(int sig, int flags) {
4325 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4326 if (sig > 0 && sig < NSIG) {
4327 sigflags[sig] = flags;
4328 }
4329 }
4330
4331 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4332 // Check for overwrite.
4333 struct sigaction oldAct;
4334 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4335
4336 void* oldhand = oldAct.sa_sigaction
4337 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4338 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4339 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4340 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4341 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4342 if (AllowUserSignalHandlers || !set_installed) {
4343 // Do not overwrite; user takes responsibility to forward to us.
4344 return;
4345 } else if (UseSignalChaining) {
4346 // save the old handler in jvm
4347 save_preinstalled_handler(sig, oldAct);
4348 // libjsig also interposes the sigaction() call below and saves the
4349 // old sigaction on it own.
4350 } else {
4351 fatal("Encountered unexpected pre-existing sigaction handler "
4352 "%#lx for signal %d.", (long)oldhand, sig);
4353 }
4354 }
4355
4356 struct sigaction sigAct;
4357 sigfillset(&(sigAct.sa_mask));
4358 sigAct.sa_handler = SIG_DFL;
4359 if (!set_installed) {
4360 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4361 } else {
4362 sigAct.sa_sigaction = signalHandler;
4363 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4364 }
4365 // Save flags, which are set by ours
4366 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4367 sigflags[sig] = sigAct.sa_flags;
4368
4369 int ret = sigaction(sig, &sigAct, &oldAct);
4370 assert(ret == 0, "check");
4371
4372 void* oldhand2 = oldAct.sa_sigaction
4373 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4374 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4375 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4376 }
4377
4378 // install signal handlers for signals that HotSpot needs to
4379 // handle in order to support Java-level exception handling.
4380
4381 void os::Linux::install_signal_handlers() {
4382 if (!signal_handlers_are_installed) {
4383 signal_handlers_are_installed = true;
4384
4385 // signal-chaining
4386 typedef void (*signal_setting_t)();
4387 signal_setting_t begin_signal_setting = NULL;
4388 signal_setting_t end_signal_setting = NULL;
4389 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4390 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4391 if (begin_signal_setting != NULL) {
4392 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4393 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4394 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4395 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4396 libjsig_is_loaded = true;
4397 assert(UseSignalChaining, "should enable signal-chaining");
4398 }
4399 if (libjsig_is_loaded) {
4400 // Tell libjsig jvm is setting signal handlers
4401 (*begin_signal_setting)();
4402 }
4403
4404 set_signal_handler(SIGSEGV, true);
4405 set_signal_handler(SIGPIPE, true);
4406 set_signal_handler(SIGBUS, true);
4407 set_signal_handler(SIGILL, true);
4408 set_signal_handler(SIGFPE, true);
4409 #if defined(PPC64)
4410 set_signal_handler(SIGTRAP, true);
4411 #endif
4412 set_signal_handler(SIGXFSZ, true);
4413
4414 if (libjsig_is_loaded) {
4415 // Tell libjsig jvm finishes setting signal handlers
4416 (*end_signal_setting)();
4417 }
4418
4419 // We don't activate signal checker if libjsig is in place, we trust ourselves
4420 // and if UserSignalHandler is installed all bets are off.
4421 // Log that signal checking is off only if -verbose:jni is specified.
4422 if (CheckJNICalls) {
4423 if (libjsig_is_loaded) {
4424 if (PrintJNIResolving) {
4425 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4426 }
4427 check_signals = false;
4428 }
4429 if (AllowUserSignalHandlers) {
4430 if (PrintJNIResolving) {
4431 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4432 }
4433 check_signals = false;
4434 }
4435 }
4436 }
4437 }
4438
4439 // This is the fastest way to get thread cpu time on Linux.
4440 // Returns cpu time (user+sys) for any thread, not only for current.
4441 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4442 // It might work on 2.6.10+ with a special kernel/glibc patch.
4443 // For reference, please, see IEEE Std 1003.1-2004:
4444 // http://www.unix.org/single_unix_specification
4445
4446 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4447 struct timespec tp;
4448 int rc = os::Linux::clock_gettime(clockid, &tp);
4449 assert(rc == 0, "clock_gettime is expected to return 0 code");
4450
4451 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4452 }
4453
4454 void os::Linux::initialize_os_info() {
4455 assert(_os_version == 0, "OS info already initialized");
4456
4457 struct utsname _uname;
4458
4459 uint32_t major;
4460 uint32_t minor;
4461 uint32_t fix;
4462
4463 int rc;
4464
4465 // Kernel version is unknown if
4466 // verification below fails.
4467 _os_version = 0x01000000;
4468
4469 rc = uname(&_uname);
4470 if (rc != -1) {
4471
4472 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4473 if (rc == 3) {
4474
4475 if (major < 256 && minor < 256 && fix < 256) {
4476 // Kernel version format is as expected,
4477 // set it overriding unknown state.
4478 _os_version = (major << 16) |
4479 (minor << 8 ) |
4480 (fix << 0 ) ;
4481 }
4482 }
4483 }
4484 }
4485
4486 uint32_t os::Linux::os_version() {
4487 assert(_os_version != 0, "not initialized");
4488 return _os_version & 0x00FFFFFF;
4489 }
4490
4491 bool os::Linux::os_version_is_known() {
4492 assert(_os_version != 0, "not initialized");
4493 return _os_version & 0x01000000 ? false : true;
4494 }
4495
4496 /////
4497 // glibc on Linux platform uses non-documented flag
4498 // to indicate, that some special sort of signal
4499 // trampoline is used.
4500 // We will never set this flag, and we should
4501 // ignore this flag in our diagnostic
4502 #ifdef SIGNIFICANT_SIGNAL_MASK
4503 #undef SIGNIFICANT_SIGNAL_MASK
4504 #endif
4505 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4506
4507 static const char* get_signal_handler_name(address handler,
4508 char* buf, int buflen) {
4509 int offset = 0;
4510 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4511 if (found) {
4512 // skip directory names
4513 const char *p1, *p2;
4514 p1 = buf;
4515 size_t len = strlen(os::file_separator());
4516 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4517 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4518 } else {
4519 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4520 }
4521 return buf;
4522 }
4523
4524 static void print_signal_handler(outputStream* st, int sig,
4525 char* buf, size_t buflen) {
4526 struct sigaction sa;
4527
4528 sigaction(sig, NULL, &sa);
4529
4530 // See comment for SIGNIFICANT_SIGNAL_MASK define
4531 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4532
4533 st->print("%s: ", os::exception_name(sig, buf, buflen));
4534
4535 address handler = (sa.sa_flags & SA_SIGINFO)
4536 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4537 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4538
4539 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4540 st->print("SIG_DFL");
4541 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4542 st->print("SIG_IGN");
4543 } else {
4544 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4545 }
4546
4547 st->print(", sa_mask[0]=");
4548 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4549
4550 address rh = VMError::get_resetted_sighandler(sig);
4551 // May be, handler was resetted by VMError?
4552 if (rh != NULL) {
4553 handler = rh;
4554 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4555 }
4556
4557 st->print(", sa_flags=");
4558 os::Posix::print_sa_flags(st, sa.sa_flags);
4559
4560 // Check: is it our handler?
4561 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4562 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4563 // It is our signal handler
4564 // check for flags, reset system-used one!
4565 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4566 st->print(
4567 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4568 os::Linux::get_our_sigflags(sig));
4569 }
4570 }
4571 st->cr();
4572 }
4573
4574
4575 #define DO_SIGNAL_CHECK(sig) \
4576 do { \
4577 if (!sigismember(&check_signal_done, sig)) { \
4578 os::Linux::check_signal_handler(sig); \
4579 } \
4580 } while (0)
4581
4582 // This method is a periodic task to check for misbehaving JNI applications
4583 // under CheckJNI, we can add any periodic checks here
4584
4585 void os::run_periodic_checks() {
4586 if (check_signals == false) return;
4587
4588 // SEGV and BUS if overridden could potentially prevent
4589 // generation of hs*.log in the event of a crash, debugging
4590 // such a case can be very challenging, so we absolutely
4591 // check the following for a good measure:
4592 DO_SIGNAL_CHECK(SIGSEGV);
4593 DO_SIGNAL_CHECK(SIGILL);
4594 DO_SIGNAL_CHECK(SIGFPE);
4595 DO_SIGNAL_CHECK(SIGBUS);
4596 DO_SIGNAL_CHECK(SIGPIPE);
4597 DO_SIGNAL_CHECK(SIGXFSZ);
4598 #if defined(PPC64)
4599 DO_SIGNAL_CHECK(SIGTRAP);
4600 #endif
4601
4602 // ReduceSignalUsage allows the user to override these handlers
4603 // see comments at the very top and jvm_solaris.h
4604 if (!ReduceSignalUsage) {
4605 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4606 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4607 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4608 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4609 }
4610
4611 DO_SIGNAL_CHECK(SR_signum);
4612 }
4613
4614 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4615
4616 static os_sigaction_t os_sigaction = NULL;
4617
4618 void os::Linux::check_signal_handler(int sig) {
4619 char buf[O_BUFLEN];
4620 address jvmHandler = NULL;
4621
4622
4623 struct sigaction act;
4624 if (os_sigaction == NULL) {
4625 // only trust the default sigaction, in case it has been interposed
4626 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4627 if (os_sigaction == NULL) return;
4628 }
4629
4630 os_sigaction(sig, (struct sigaction*)NULL, &act);
4631
4632
4633 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4634
4635 address thisHandler = (act.sa_flags & SA_SIGINFO)
4636 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4637 : CAST_FROM_FN_PTR(address, act.sa_handler);
4638
4639
4640 switch (sig) {
4641 case SIGSEGV:
4642 case SIGBUS:
4643 case SIGFPE:
4644 case SIGPIPE:
4645 case SIGILL:
4646 case SIGXFSZ:
4647 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4648 break;
4649
4650 case SHUTDOWN1_SIGNAL:
4651 case SHUTDOWN2_SIGNAL:
4652 case SHUTDOWN3_SIGNAL:
4653 case BREAK_SIGNAL:
4654 jvmHandler = (address)user_handler();
4655 break;
4656
4657 default:
4658 if (sig == SR_signum) {
4659 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4660 } else {
4661 return;
4662 }
4663 break;
4664 }
4665
4666 if (thisHandler != jvmHandler) {
4667 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4668 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4669 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4670 // No need to check this sig any longer
4671 sigaddset(&check_signal_done, sig);
4672 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4673 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4674 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4675 exception_name(sig, buf, O_BUFLEN));
4676 }
4677 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4678 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4679 tty->print("expected:");
4680 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4681 tty->cr();
4682 tty->print(" found:");
4683 os::Posix::print_sa_flags(tty, act.sa_flags);
4684 tty->cr();
4685 // No need to check this sig any longer
4686 sigaddset(&check_signal_done, sig);
4687 }
4688
4689 // Dump all the signal
4690 if (sigismember(&check_signal_done, sig)) {
4691 print_signal_handlers(tty, buf, O_BUFLEN);
4692 }
4693 }
4694
4695 extern void report_error(char* file_name, int line_no, char* title,
4696 char* format, ...);
4697
4698 // this is called _before_ the most of global arguments have been parsed
4699 void os::init(void) {
4700 char dummy; // used to get a guess on initial stack address
4701 // first_hrtime = gethrtime();
4702
4703 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4704
4705 init_random(1234567);
4706
4707 ThreadCritical::initialize();
4708
4709 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4710 if (Linux::page_size() == -1) {
4711 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4712 os::strerror(errno));
4713 }
4714 init_page_sizes((size_t) Linux::page_size());
4715
4716 Linux::initialize_system_info();
4717
4718 Linux::initialize_os_info();
4719
4720 // main_thread points to the aboriginal thread
4721 Linux::_main_thread = pthread_self();
4722
4723 Linux::clock_init();
4724 initial_time_count = javaTimeNanos();
4725
4726 // pthread_condattr initialization for monotonic clock
4727 int status;
4728 pthread_condattr_t* _condattr = os::Linux::condAttr();
4729 if ((status = pthread_condattr_init(_condattr)) != 0) {
4730 fatal("pthread_condattr_init: %s", os::strerror(status));
4731 }
4732 // Only set the clock if CLOCK_MONOTONIC is available
4733 if (os::supports_monotonic_clock()) {
4734 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4735 if (status == EINVAL) {
4736 warning("Unable to use monotonic clock with relative timed-waits" \
4737 " - changes to the time-of-day clock may have adverse affects");
4738 } else {
4739 fatal("pthread_condattr_setclock: %s", os::strerror(status));
4740 }
4741 }
4742 }
4743 // else it defaults to CLOCK_REALTIME
4744
4745 // retrieve entry point for pthread_setname_np
4746 Linux::_pthread_setname_np =
4747 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4748
4749 }
4750
4751 // To install functions for atexit system call
4752 extern "C" {
4753 static void perfMemory_exit_helper() {
4754 perfMemory_exit();
4755 }
4756 }
4757
4758 // this is called _after_ the global arguments have been parsed
4759 jint os::init_2(void) {
4760 Linux::fast_thread_clock_init();
4761
4762 // Allocate a single page and mark it as readable for safepoint polling
4763 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4764 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4765
4766 os::set_polling_page(polling_page);
4767 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4768
4769 if (!UseMembar) {
4770 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4771 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4772 os::set_memory_serialize_page(mem_serialize_page);
4773 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4774 }
4775
4776 // initialize suspend/resume support - must do this before signal_sets_init()
4777 if (SR_initialize() != 0) {
4778 perror("SR_initialize failed");
4779 return JNI_ERR;
4780 }
4781
4782 Linux::signal_sets_init();
4783 Linux::install_signal_handlers();
4784
4785 // Check minimum allowable stack size for thread creation and to initialize
4786 // the java system classes, including StackOverflowError - depends on page
4787 // size. Add a page for compiler2 recursion in main thread.
4788 // Add in 2*BytesPerWord times page size to account for VM stack during
4789 // class initialization depending on 32 or 64 bit VM.
4790 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4791 JavaThread::stack_guard_zone_size() +
4792 JavaThread::stack_shadow_zone_size() +
4793 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4794
4795 size_t threadStackSizeInBytes = ThreadStackSize * K;
4796 if (threadStackSizeInBytes != 0 &&
4797 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4798 tty->print_cr("\nThe stack size specified is too small, "
4799 "Specify at least " SIZE_FORMAT "k",
4800 os::Linux::min_stack_allowed/ K);
4801 return JNI_ERR;
4802 }
4803
4804 // Make the stack size a multiple of the page size so that
4805 // the yellow/red zones can be guarded.
4806 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4807 vm_page_size()));
4808
4809 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4810
4811 #if defined(IA32)
4812 workaround_expand_exec_shield_cs_limit();
4813 #endif
4814
4815 Linux::libpthread_init();
4816 log_info(os)("HotSpot is running with %s, %s",
4817 Linux::glibc_version(), Linux::libpthread_version());
4818
4819 if (UseNUMA) {
4820 if (!Linux::libnuma_init()) {
4821 UseNUMA = false;
4822 } else {
4823 if ((Linux::numa_max_node() < 1)) {
4824 // There's only one node(they start from 0), disable NUMA.
4825 UseNUMA = false;
4826 }
4827 }
4828 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4829 // we can make the adaptive lgrp chunk resizing work. If the user specified
4830 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4831 // disable adaptive resizing.
4832 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4833 if (FLAG_IS_DEFAULT(UseNUMA)) {
4834 UseNUMA = false;
4835 } else {
4836 if (FLAG_IS_DEFAULT(UseLargePages) &&
4837 FLAG_IS_DEFAULT(UseSHM) &&
4838 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4839 UseLargePages = false;
4840 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4841 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4842 UseAdaptiveSizePolicy = false;
4843 UseAdaptiveNUMAChunkSizing = false;
4844 }
4845 }
4846 }
4847 if (!UseNUMA && ForceNUMA) {
4848 UseNUMA = true;
4849 }
4850 }
4851
4852 if (MaxFDLimit) {
4853 // set the number of file descriptors to max. print out error
4854 // if getrlimit/setrlimit fails but continue regardless.
4855 struct rlimit nbr_files;
4856 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4857 if (status != 0) {
4858 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4859 } else {
4860 nbr_files.rlim_cur = nbr_files.rlim_max;
4861 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4862 if (status != 0) {
4863 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4864 }
4865 }
4866 }
4867
4868 // Initialize lock used to serialize thread creation (see os::create_thread)
4869 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4870
4871 // at-exit methods are called in the reverse order of their registration.
4872 // atexit functions are called on return from main or as a result of a
4873 // call to exit(3C). There can be only 32 of these functions registered
4874 // and atexit() does not set errno.
4875
4876 if (PerfAllowAtExitRegistration) {
4877 // only register atexit functions if PerfAllowAtExitRegistration is set.
4878 // atexit functions can be delayed until process exit time, which
4879 // can be problematic for embedded VM situations. Embedded VMs should
4880 // call DestroyJavaVM() to assure that VM resources are released.
4881
4882 // note: perfMemory_exit_helper atexit function may be removed in
4883 // the future if the appropriate cleanup code can be added to the
4884 // VM_Exit VMOperation's doit method.
4885 if (atexit(perfMemory_exit_helper) != 0) {
4886 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4887 }
4888 }
4889
4890 // initialize thread priority policy
4891 prio_init();
4892
4893 return JNI_OK;
4894 }
4895
4896 // Mark the polling page as unreadable
4897 void os::make_polling_page_unreadable(void) {
4898 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4899 fatal("Could not disable polling page");
4900 }
4901 }
4902
4903 // Mark the polling page as readable
4904 void os::make_polling_page_readable(void) {
4905 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4906 fatal("Could not enable polling page");
4907 }
4908 }
4909
4910 // older glibc versions don't have this macro (which expands to
4911 // an optimized bit-counting function) so we have to roll our own
4912 #ifndef CPU_COUNT
4913
4914 static int _cpu_count(const cpu_set_t* cpus) {
4915 int count = 0;
4916 // only look up to the number of configured processors
4917 for (int i = 0; i < os::processor_count(); i++) {
4918 if (CPU_ISSET(i, cpus)) {
4919 count++;
4920 }
4921 }
4922 return count;
4923 }
4924
4925 #define CPU_COUNT(cpus) _cpu_count(cpus)
4926
4927 #endif // CPU_COUNT
4928
4929 // Get the current number of available processors for this process.
4930 // This value can change at any time during a process's lifetime.
4931 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4932 // If it appears there may be more than 1024 processors then we do a
4933 // dynamic check - see 6515172 for details.
4934 // If anything goes wrong we fallback to returning the number of online
4935 // processors - which can be greater than the number available to the process.
4936 int os::active_processor_count() {
4937 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4938 cpu_set_t* cpus_p = &cpus;
4939 int cpus_size = sizeof(cpu_set_t);
4940
4941 int configured_cpus = processor_count(); // upper bound on available cpus
4942 int cpu_count = 0;
4943
4944 // old build platforms may not support dynamic cpu sets
4945 #ifdef CPU_ALLOC
4946
4947 // To enable easy testing of the dynamic path on different platforms we
4948 // introduce a diagnostic flag: UseCpuAllocPath
4949 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4950 // kernel may use a mask bigger than cpu_set_t
4951 log_trace(os)("active_processor_count: using dynamic path %s"
4952 "- configured processors: %d",
4953 UseCpuAllocPath ? "(forced) " : "",
4954 configured_cpus);
4955 cpus_p = CPU_ALLOC(configured_cpus);
4956 if (cpus_p != NULL) {
4957 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4958 // zero it just to be safe
4959 CPU_ZERO_S(cpus_size, cpus_p);
4960 }
4961 else {
4962 // failed to allocate so fallback to online cpus
4963 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4964 log_trace(os)("active_processor_count: "
4965 "CPU_ALLOC failed (%s) - using "
4966 "online processor count: %d",
4967 os::strerror(errno), online_cpus);
4968 return online_cpus;
4969 }
4970 }
4971 else {
4972 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4973 configured_cpus);
4974 }
4975 #else // CPU_ALLOC
4976 // these stubs won't be executed
4977 #define CPU_COUNT_S(size, cpus) -1
4978 #define CPU_FREE(cpus)
4979
4980 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4981 configured_cpus);
4982 #endif // CPU_ALLOC
4983
4984 // pid 0 means the current thread - which we have to assume represents the process
4985 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4986 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4987 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4988 }
4989 else {
4990 cpu_count = CPU_COUNT(cpus_p);
4991 }
4992 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
4993 }
4994 else {
4995 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
4996 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
4997 "which may exceed available processors", os::strerror(errno), cpu_count);
4998 }
4999
5000 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5001 CPU_FREE(cpus_p);
5002 }
5003
5004 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
5005 return cpu_count;
5006 }
5007
5008 void os::set_native_thread_name(const char *name) {
5009 if (Linux::_pthread_setname_np) {
5010 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5011 snprintf(buf, sizeof(buf), "%s", name);
5012 buf[sizeof(buf) - 1] = '\0';
5013 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5014 // ERANGE should not happen; all other errors should just be ignored.
5015 assert(rc != ERANGE, "pthread_setname_np failed");
5016 }
5017 }
5018
5019 bool os::distribute_processes(uint length, uint* distribution) {
5020 // Not yet implemented.
5021 return false;
5022 }
5023
5024 bool os::bind_to_processor(uint processor_id) {
5025 // Not yet implemented.
5026 return false;
5027 }
5028
5029 ///
5030
5031 void os::SuspendedThreadTask::internal_do_task() {
5032 if (do_suspend(_thread->osthread())) {
5033 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5034 do_task(context);
5035 do_resume(_thread->osthread());
5036 }
5037 }
5038
5039 class PcFetcher : public os::SuspendedThreadTask {
5040 public:
5041 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5042 ExtendedPC result();
5043 protected:
5044 void do_task(const os::SuspendedThreadTaskContext& context);
5045 private:
5046 ExtendedPC _epc;
5047 };
5048
5049 ExtendedPC PcFetcher::result() {
5050 guarantee(is_done(), "task is not done yet.");
5051 return _epc;
5052 }
5053
5054 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5055 Thread* thread = context.thread();
5056 OSThread* osthread = thread->osthread();
5057 if (osthread->ucontext() != NULL) {
5058 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5059 } else {
5060 // NULL context is unexpected, double-check this is the VMThread
5061 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5062 }
5063 }
5064
5065 // Suspends the target using the signal mechanism and then grabs the PC before
5066 // resuming the target. Used by the flat-profiler only
5067 ExtendedPC os::get_thread_pc(Thread* thread) {
5068 // Make sure that it is called by the watcher for the VMThread
5069 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5070 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5071
5072 PcFetcher fetcher(thread);
5073 fetcher.run();
5074 return fetcher.result();
5075 }
5076
5077 ////////////////////////////////////////////////////////////////////////////////
5078 // debug support
5079
5080 bool os::find(address addr, outputStream* st) {
5081 Dl_info dlinfo;
5082 memset(&dlinfo, 0, sizeof(dlinfo));
5083 if (dladdr(addr, &dlinfo) != 0) {
5084 st->print(PTR_FORMAT ": ", p2i(addr));
5085 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5086 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5087 p2i(addr) - p2i(dlinfo.dli_saddr));
5088 } else if (dlinfo.dli_fbase != NULL) {
5089 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5090 } else {
5091 st->print("<absolute address>");
5092 }
5093 if (dlinfo.dli_fname != NULL) {
5094 st->print(" in %s", dlinfo.dli_fname);
5095 }
5096 if (dlinfo.dli_fbase != NULL) {
5097 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5098 }
5099 st->cr();
5100
5101 if (Verbose) {
5102 // decode some bytes around the PC
5103 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5104 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5105 address lowest = (address) dlinfo.dli_sname;
5106 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5107 if (begin < lowest) begin = lowest;
5108 Dl_info dlinfo2;
5109 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5110 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5111 end = (address) dlinfo2.dli_saddr;
5112 }
5113 Disassembler::decode(begin, end, st);
5114 }
5115 return true;
5116 }
5117 return false;
5118 }
5119
5120 ////////////////////////////////////////////////////////////////////////////////
5121 // misc
5122
5123 // This does not do anything on Linux. This is basically a hook for being
5124 // able to use structured exception handling (thread-local exception filters)
5125 // on, e.g., Win32.
5126 void
5127 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5128 JavaCallArguments* args, Thread* thread) {
5129 f(value, method, args, thread);
5130 }
5131
5132 void os::print_statistics() {
5133 }
5134
5135 bool os::message_box(const char* title, const char* message) {
5136 int i;
5137 fdStream err(defaultStream::error_fd());
5138 for (i = 0; i < 78; i++) err.print_raw("=");
5139 err.cr();
5140 err.print_raw_cr(title);
5141 for (i = 0; i < 78; i++) err.print_raw("-");
5142 err.cr();
5143 err.print_raw_cr(message);
5144 for (i = 0; i < 78; i++) err.print_raw("=");
5145 err.cr();
5146
5147 char buf[16];
5148 // Prevent process from exiting upon "read error" without consuming all CPU
5149 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5150
5151 return buf[0] == 'y' || buf[0] == 'Y';
5152 }
5153
5154 int os::stat(const char *path, struct stat *sbuf) {
5155 char pathbuf[MAX_PATH];
5156 if (strlen(path) > MAX_PATH - 1) {
5157 errno = ENAMETOOLONG;
5158 return -1;
5159 }
5160 os::native_path(strcpy(pathbuf, path));
5161 return ::stat(pathbuf, sbuf);
5162 }
5163
5164 bool os::check_heap(bool force) {
5165 return true;
5166 }
5167
5168 // Is a (classpath) directory empty?
5169 bool os::dir_is_empty(const char* path) {
5170 DIR *dir = NULL;
5171 struct dirent *ptr;
5172
5173 dir = opendir(path);
5174 if (dir == NULL) return true;
5175
5176 // Scan the directory
5177 bool result = true;
5178 char buf[sizeof(struct dirent) + MAX_PATH];
5179 while (result && (ptr = ::readdir(dir)) != NULL) {
5180 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5181 result = false;
5182 }
5183 }
5184 closedir(dir);
5185 return result;
5186 }
5187
5188 // This code originates from JDK's sysOpen and open64_w
5189 // from src/solaris/hpi/src/system_md.c
5190
5191 int os::open(const char *path, int oflag, int mode) {
5192 if (strlen(path) > MAX_PATH - 1) {
5193 errno = ENAMETOOLONG;
5194 return -1;
5195 }
5196
5197 // All file descriptors that are opened in the Java process and not
5198 // specifically destined for a subprocess should have the close-on-exec
5199 // flag set. If we don't set it, then careless 3rd party native code
5200 // might fork and exec without closing all appropriate file descriptors
5201 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5202 // turn might:
5203 //
5204 // - cause end-of-file to fail to be detected on some file
5205 // descriptors, resulting in mysterious hangs, or
5206 //
5207 // - might cause an fopen in the subprocess to fail on a system
5208 // suffering from bug 1085341.
5209 //
5210 // (Yes, the default setting of the close-on-exec flag is a Unix
5211 // design flaw)
5212 //
5213 // See:
5214 // 1085341: 32-bit stdio routines should support file descriptors >255
5215 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5216 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5217 //
5218 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5219 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5220 // because it saves a system call and removes a small window where the flag
5221 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5222 // and we fall back to using FD_CLOEXEC (see below).
5223 #ifdef O_CLOEXEC
5224 oflag |= O_CLOEXEC;
5225 #endif
5226
5227 int fd = ::open64(path, oflag, mode);
5228 if (fd == -1) return -1;
5229
5230 //If the open succeeded, the file might still be a directory
5231 {
5232 struct stat64 buf64;
5233 int ret = ::fstat64(fd, &buf64);
5234 int st_mode = buf64.st_mode;
5235
5236 if (ret != -1) {
5237 if ((st_mode & S_IFMT) == S_IFDIR) {
5238 errno = EISDIR;
5239 ::close(fd);
5240 return -1;
5241 }
5242 } else {
5243 ::close(fd);
5244 return -1;
5245 }
5246 }
5247
5248 #ifdef FD_CLOEXEC
5249 // Validate that the use of the O_CLOEXEC flag on open above worked.
5250 // With recent kernels, we will perform this check exactly once.
5251 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5252 if (!O_CLOEXEC_is_known_to_work) {
5253 int flags = ::fcntl(fd, F_GETFD);
5254 if (flags != -1) {
5255 if ((flags & FD_CLOEXEC) != 0)
5256 O_CLOEXEC_is_known_to_work = 1;
5257 else
5258 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5259 }
5260 }
5261 #endif
5262
5263 return fd;
5264 }
5265
5266
5267 // create binary file, rewriting existing file if required
5268 int os::create_binary_file(const char* path, bool rewrite_existing) {
5269 int oflags = O_WRONLY | O_CREAT;
5270 if (!rewrite_existing) {
5271 oflags |= O_EXCL;
5272 }
5273 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5274 }
5275
5276 // return current position of file pointer
5277 jlong os::current_file_offset(int fd) {
5278 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5279 }
5280
5281 // move file pointer to the specified offset
5282 jlong os::seek_to_file_offset(int fd, jlong offset) {
5283 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5284 }
5285
5286 // This code originates from JDK's sysAvailable
5287 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5288
5289 int os::available(int fd, jlong *bytes) {
5290 jlong cur, end;
5291 int mode;
5292 struct stat64 buf64;
5293
5294 if (::fstat64(fd, &buf64) >= 0) {
5295 mode = buf64.st_mode;
5296 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5297 int n;
5298 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5299 *bytes = n;
5300 return 1;
5301 }
5302 }
5303 }
5304 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5305 return 0;
5306 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5307 return 0;
5308 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5309 return 0;
5310 }
5311 *bytes = end - cur;
5312 return 1;
5313 }
5314
5315 // Map a block of memory.
5316 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5317 char *addr, size_t bytes, bool read_only,
5318 bool allow_exec) {
5319 int prot;
5320 int flags = MAP_PRIVATE;
5321
5322 if (read_only) {
5323 prot = PROT_READ;
5324 } else {
5325 prot = PROT_READ | PROT_WRITE;
5326 }
5327
5328 if (allow_exec) {
5329 prot |= PROT_EXEC;
5330 }
5331
5332 if (addr != NULL) {
5333 flags |= MAP_FIXED;
5334 }
5335
5336 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5337 fd, file_offset);
5338 if (mapped_address == MAP_FAILED) {
5339 return NULL;
5340 }
5341 return mapped_address;
5342 }
5343
5344
5345 // Remap a block of memory.
5346 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5347 char *addr, size_t bytes, bool read_only,
5348 bool allow_exec) {
5349 // same as map_memory() on this OS
5350 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5351 allow_exec);
5352 }
5353
5354
5355 // Unmap a block of memory.
5356 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5357 return munmap(addr, bytes) == 0;
5358 }
5359
5360 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5361
5362 static clockid_t thread_cpu_clockid(Thread* thread) {
5363 pthread_t tid = thread->osthread()->pthread_id();
5364 clockid_t clockid;
5365
5366 // Get thread clockid
5367 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5368 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5369 return clockid;
5370 }
5371
5372 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5373 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5374 // of a thread.
5375 //
5376 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5377 // the fast estimate available on the platform.
5378
5379 jlong os::current_thread_cpu_time() {
5380 if (os::Linux::supports_fast_thread_cpu_time()) {
5381 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5382 } else {
5383 // return user + sys since the cost is the same
5384 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5385 }
5386 }
5387
5388 jlong os::thread_cpu_time(Thread* thread) {
5389 // consistent with what current_thread_cpu_time() returns
5390 if (os::Linux::supports_fast_thread_cpu_time()) {
5391 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5392 } else {
5393 return slow_thread_cpu_time(thread, true /* user + sys */);
5394 }
5395 }
5396
5397 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5398 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5399 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5400 } else {
5401 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5402 }
5403 }
5404
5405 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5406 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5407 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5408 } else {
5409 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5410 }
5411 }
5412
5413 // -1 on error.
5414 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5415 pid_t tid = thread->osthread()->thread_id();
5416 char *s;
5417 char stat[2048];
5418 int statlen;
5419 char proc_name[64];
5420 int count;
5421 long sys_time, user_time;
5422 char cdummy;
5423 int idummy;
5424 long ldummy;
5425 FILE *fp;
5426
5427 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5428 fp = fopen(proc_name, "r");
5429 if (fp == NULL) return -1;
5430 statlen = fread(stat, 1, 2047, fp);
5431 stat[statlen] = '\0';
5432 fclose(fp);
5433
5434 // Skip pid and the command string. Note that we could be dealing with
5435 // weird command names, e.g. user could decide to rename java launcher
5436 // to "java 1.4.2 :)", then the stat file would look like
5437 // 1234 (java 1.4.2 :)) R ... ...
5438 // We don't really need to know the command string, just find the last
5439 // occurrence of ")" and then start parsing from there. See bug 4726580.
5440 s = strrchr(stat, ')');
5441 if (s == NULL) return -1;
5442
5443 // Skip blank chars
5444 do { s++; } while (s && isspace(*s));
5445
5446 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5447 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5448 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5449 &user_time, &sys_time);
5450 if (count != 13) return -1;
5451 if (user_sys_cpu_time) {
5452 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5453 } else {
5454 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5455 }
5456 }
5457
5458 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5459 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5460 info_ptr->may_skip_backward = false; // elapsed time not wall time
5461 info_ptr->may_skip_forward = false; // elapsed time not wall time
5462 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5463 }
5464
5465 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5466 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5467 info_ptr->may_skip_backward = false; // elapsed time not wall time
5468 info_ptr->may_skip_forward = false; // elapsed time not wall time
5469 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5470 }
5471
5472 bool os::is_thread_cpu_time_supported() {
5473 return true;
5474 }
5475
5476 // System loadavg support. Returns -1 if load average cannot be obtained.
5477 // Linux doesn't yet have a (official) notion of processor sets,
5478 // so just return the system wide load average.
5479 int os::loadavg(double loadavg[], int nelem) {
5480 return ::getloadavg(loadavg, nelem);
5481 }
5482
5483 void os::pause() {
5484 char filename[MAX_PATH];
5485 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5486 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5487 } else {
5488 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5489 }
5490
5491 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5492 if (fd != -1) {
5493 struct stat buf;
5494 ::close(fd);
5495 while (::stat(filename, &buf) == 0) {
5496 (void)::poll(NULL, 0, 100);
5497 }
5498 } else {
5499 jio_fprintf(stderr,
5500 "Could not open pause file '%s', continuing immediately.\n", filename);
5501 }
5502 }
5503
5504
5505 // Refer to the comments in os_solaris.cpp park-unpark. The next two
5506 // comment paragraphs are worth repeating here:
5507 //
5508 // Assumption:
5509 // Only one parker can exist on an event, which is why we allocate
5510 // them per-thread. Multiple unparkers can coexist.
5511 //
5512 // _Event serves as a restricted-range semaphore.
5513 // -1 : thread is blocked, i.e. there is a waiter
5514 // 0 : neutral: thread is running or ready,
5515 // could have been signaled after a wait started
5516 // 1 : signaled - thread is running or ready
5517 //
5518
5519 // utility to compute the abstime argument to timedwait:
5520 // millis is the relative timeout time
5521 // abstime will be the absolute timeout time
5522 // TODO: replace compute_abstime() with unpackTime()
5523
5524 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5525 if (millis < 0) millis = 0;
5526
5527 jlong seconds = millis / 1000;
5528 millis %= 1000;
5529 if (seconds > 50000000) { // see man cond_timedwait(3T)
5530 seconds = 50000000;
5531 }
5532
5533 if (os::supports_monotonic_clock()) {
5534 struct timespec now;
5535 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5536 assert_status(status == 0, status, "clock_gettime");
5537 abstime->tv_sec = now.tv_sec + seconds;
5538 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5539 if (nanos >= NANOSECS_PER_SEC) {
5540 abstime->tv_sec += 1;
5541 nanos -= NANOSECS_PER_SEC;
5542 }
5543 abstime->tv_nsec = nanos;
5544 } else {
5545 struct timeval now;
5546 int status = gettimeofday(&now, NULL);
5547 assert(status == 0, "gettimeofday");
5548 abstime->tv_sec = now.tv_sec + seconds;
5549 long usec = now.tv_usec + millis * 1000;
5550 if (usec >= 1000000) {
5551 abstime->tv_sec += 1;
5552 usec -= 1000000;
5553 }
5554 abstime->tv_nsec = usec * 1000;
5555 }
5556 return abstime;
5557 }
5558
5559 void os::PlatformEvent::park() { // AKA "down()"
5560 // Transitions for _Event:
5561 // -1 => -1 : illegal
5562 // 1 => 0 : pass - return immediately
5563 // 0 => -1 : block; then set _Event to 0 before returning
5564
5565 // Invariant: Only the thread associated with the Event/PlatformEvent
5566 // may call park().
5567 // TODO: assert that _Assoc != NULL or _Assoc == Self
5568 assert(_nParked == 0, "invariant");
5569
5570 int v;
5571 for (;;) {
5572 v = _Event;
5573 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5574 }
5575 guarantee(v >= 0, "invariant");
5576 if (v == 0) {
5577 // Do this the hard way by blocking ...
5578 int status = pthread_mutex_lock(_mutex);
5579 assert_status(status == 0, status, "mutex_lock");
5580 guarantee(_nParked == 0, "invariant");
5581 ++_nParked;
5582 while (_Event < 0) {
5583 status = pthread_cond_wait(_cond, _mutex);
5584 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5585 // Treat this the same as if the wait was interrupted
5586 if (status == ETIME) { status = EINTR; }
5587 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5588 }
5589 --_nParked;
5590
5591 _Event = 0;
5592 status = pthread_mutex_unlock(_mutex);
5593 assert_status(status == 0, status, "mutex_unlock");
5594 // Paranoia to ensure our locked and lock-free paths interact
5595 // correctly with each other.
5596 OrderAccess::fence();
5597 }
5598 guarantee(_Event >= 0, "invariant");
5599 }
5600
5601 int os::PlatformEvent::park(jlong millis) {
5602 // Transitions for _Event:
5603 // -1 => -1 : illegal
5604 // 1 => 0 : pass - return immediately
5605 // 0 => -1 : block; then set _Event to 0 before returning
5606
5607 guarantee(_nParked == 0, "invariant");
5608
5609 int v;
5610 for (;;) {
5611 v = _Event;
5612 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5613 }
5614 guarantee(v >= 0, "invariant");
5615 if (v != 0) return OS_OK;
5616
5617 // We do this the hard way, by blocking the thread.
5618 // Consider enforcing a minimum timeout value.
5619 struct timespec abst;
5620 compute_abstime(&abst, millis);
5621
5622 int ret = OS_TIMEOUT;
5623 int status = pthread_mutex_lock(_mutex);
5624 assert_status(status == 0, status, "mutex_lock");
5625 guarantee(_nParked == 0, "invariant");
5626 ++_nParked;
5627
5628 // Object.wait(timo) will return because of
5629 // (a) notification
5630 // (b) timeout
5631 // (c) thread.interrupt
5632 //
5633 // Thread.interrupt and object.notify{All} both call Event::set.
5634 // That is, we treat thread.interrupt as a special case of notification.
5635 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
5636 // We assume all ETIME returns are valid.
5637 //
5638 // TODO: properly differentiate simultaneous notify+interrupt.
5639 // In that case, we should propagate the notify to another waiter.
5640
5641 while (_Event < 0) {
5642 status = pthread_cond_timedwait(_cond, _mutex, &abst);
5643 assert_status(status == 0 || status == EINTR ||
5644 status == ETIME || status == ETIMEDOUT,
5645 status, "cond_timedwait");
5646 if (!FilterSpuriousWakeups) break; // previous semantics
5647 if (status == ETIME || status == ETIMEDOUT) break;
5648 // We consume and ignore EINTR and spurious wakeups.
5649 }
5650 --_nParked;
5651 if (_Event >= 0) {
5652 ret = OS_OK;
5653 }
5654 _Event = 0;
5655 status = pthread_mutex_unlock(_mutex);
5656 assert_status(status == 0, status, "mutex_unlock");
5657 assert(_nParked == 0, "invariant");
5658 // Paranoia to ensure our locked and lock-free paths interact
5659 // correctly with each other.
5660 OrderAccess::fence();
5661 return ret;
5662 }
5663
5664 void os::PlatformEvent::unpark() {
5665 // Transitions for _Event:
5666 // 0 => 1 : just return
5667 // 1 => 1 : just return
5668 // -1 => either 0 or 1; must signal target thread
5669 // That is, we can safely transition _Event from -1 to either
5670 // 0 or 1.
5671 // See also: "Semaphores in Plan 9" by Mullender & Cox
5672 //
5673 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5674 // that it will take two back-to-back park() calls for the owning
5675 // thread to block. This has the benefit of forcing a spurious return
5676 // from the first park() call after an unpark() call which will help
5677 // shake out uses of park() and unpark() without condition variables.
5678
5679 if (Atomic::xchg(1, &_Event) >= 0) return;
5680
5681 // Wait for the thread associated with the event to vacate
5682 int status = pthread_mutex_lock(_mutex);
5683 assert_status(status == 0, status, "mutex_lock");
5684 int AnyWaiters = _nParked;
5685 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5686 status = pthread_mutex_unlock(_mutex);
5687 assert_status(status == 0, status, "mutex_unlock");
5688 if (AnyWaiters != 0) {
5689 // Note that we signal() *after* dropping the lock for "immortal" Events.
5690 // This is safe and avoids a common class of futile wakeups. In rare
5691 // circumstances this can cause a thread to return prematurely from
5692 // cond_{timed}wait() but the spurious wakeup is benign and the victim
5693 // will simply re-test the condition and re-park itself.
5694 // This provides particular benefit if the underlying platform does not
5695 // provide wait morphing.
5696 status = pthread_cond_signal(_cond);
5697 assert_status(status == 0, status, "cond_signal");
5698 }
5699 }
5700
5701
5702 // JSR166
5703 // -------------------------------------------------------
5704
5705 // The solaris and linux implementations of park/unpark are fairly
5706 // conservative for now, but can be improved. They currently use a
5707 // mutex/condvar pair, plus a a count.
5708 // Park decrements count if > 0, else does a condvar wait. Unpark
5709 // sets count to 1 and signals condvar. Only one thread ever waits
5710 // on the condvar. Contention seen when trying to park implies that someone
5711 // is unparking you, so don't wait. And spurious returns are fine, so there
5712 // is no need to track notifications.
5713
5714 // This code is common to linux and solaris and will be moved to a
5715 // common place in dolphin.
5716 //
5717 // The passed in time value is either a relative time in nanoseconds
5718 // or an absolute time in milliseconds. Either way it has to be unpacked
5719 // into suitable seconds and nanoseconds components and stored in the
5720 // given timespec structure.
5721 // Given time is a 64-bit value and the time_t used in the timespec is only
5722 // a signed-32-bit value (except on 64-bit Linux) we have to watch for
5723 // overflow if times way in the future are given. Further on Solaris versions
5724 // prior to 10 there is a restriction (see cond_timedwait) that the specified
5725 // number of seconds, in abstime, is less than current_time + 100,000,000.
5726 // As it will be 28 years before "now + 100000000" will overflow we can
5727 // ignore overflow and just impose a hard-limit on seconds using the value
5728 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
5729 // years from "now".
5730
5731 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5732 assert(time > 0, "convertTime");
5733 time_t max_secs = 0;
5734
5735 if (!os::supports_monotonic_clock() || isAbsolute) {
5736 struct timeval now;
5737 int status = gettimeofday(&now, NULL);
5738 assert(status == 0, "gettimeofday");
5739
5740 max_secs = now.tv_sec + MAX_SECS;
5741
5742 if (isAbsolute) {
5743 jlong secs = time / 1000;
5744 if (secs > max_secs) {
5745 absTime->tv_sec = max_secs;
5746 } else {
5747 absTime->tv_sec = secs;
5748 }
5749 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5750 } else {
5751 jlong secs = time / NANOSECS_PER_SEC;
5752 if (secs >= MAX_SECS) {
5753 absTime->tv_sec = max_secs;
5754 absTime->tv_nsec = 0;
5755 } else {
5756 absTime->tv_sec = now.tv_sec + secs;
5757 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5758 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5759 absTime->tv_nsec -= NANOSECS_PER_SEC;
5760 ++absTime->tv_sec; // note: this must be <= max_secs
5761 }
5762 }
5763 }
5764 } else {
5765 // must be relative using monotonic clock
5766 struct timespec now;
5767 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5768 assert_status(status == 0, status, "clock_gettime");
5769 max_secs = now.tv_sec + MAX_SECS;
5770 jlong secs = time / NANOSECS_PER_SEC;
5771 if (secs >= MAX_SECS) {
5772 absTime->tv_sec = max_secs;
5773 absTime->tv_nsec = 0;
5774 } else {
5775 absTime->tv_sec = now.tv_sec + secs;
5776 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5777 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5778 absTime->tv_nsec -= NANOSECS_PER_SEC;
5779 ++absTime->tv_sec; // note: this must be <= max_secs
5780 }
5781 }
5782 }
5783 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5784 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5785 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5786 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5787 }
5788
5789 void Parker::park(bool isAbsolute, jlong time) {
5790 // Ideally we'd do something useful while spinning, such
5791 // as calling unpackTime().
5792
5793 // Optional fast-path check:
5794 // Return immediately if a permit is available.
5795 // We depend on Atomic::xchg() having full barrier semantics
5796 // since we are doing a lock-free update to _counter.
5797 if (Atomic::xchg(0, &_counter) > 0) return;
5798
5799 Thread* thread = Thread::current();
5800 assert(thread->is_Java_thread(), "Must be JavaThread");
5801 JavaThread *jt = (JavaThread *)thread;
5802
5803 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5804 // Check interrupt before trying to wait
5805 if (Thread::is_interrupted(thread, false)) {
5806 return;
5807 }
5808
5809 // Next, demultiplex/decode time arguments
5810 timespec absTime;
5811 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
5812 return;
5813 }
5814 if (time > 0) {
5815 unpackTime(&absTime, isAbsolute, time);
5816 }
5817
5818
5819 // Enter safepoint region
5820 // Beware of deadlocks such as 6317397.
5821 // The per-thread Parker:: mutex is a classic leaf-lock.
5822 // In particular a thread must never block on the Threads_lock while
5823 // holding the Parker:: mutex. If safepoints are pending both the
5824 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5825 ThreadBlockInVM tbivm(jt);
5826
5827 // Don't wait if cannot get lock since interference arises from
5828 // unblocking. Also. check interrupt before trying wait
5829 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5830 return;
5831 }
5832
5833 int status;
5834 if (_counter > 0) { // no wait needed
5835 _counter = 0;
5836 status = pthread_mutex_unlock(_mutex);
5837 assert_status(status == 0, status, "invariant");
5838 // Paranoia to ensure our locked and lock-free paths interact
5839 // correctly with each other and Java-level accesses.
5840 OrderAccess::fence();
5841 return;
5842 }
5843
5844 #ifdef ASSERT
5845 // Don't catch signals while blocked; let the running threads have the signals.
5846 // (This allows a debugger to break into the running thread.)
5847 sigset_t oldsigs;
5848 sigemptyset(&oldsigs);
5849 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5850 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5851 #endif
5852
5853 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5854 jt->set_suspend_equivalent();
5855 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5856
5857 assert(_cur_index == -1, "invariant");
5858 if (time == 0) {
5859 _cur_index = REL_INDEX; // arbitrary choice when not timed
5860 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
5861 } else {
5862 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5863 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
5864 }
5865 _cur_index = -1;
5866 assert_status(status == 0 || status == EINTR ||
5867 status == ETIME || status == ETIMEDOUT,
5868 status, "cond_timedwait");
5869
5870 #ifdef ASSERT
5871 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5872 #endif
5873
5874 _counter = 0;
5875 status = pthread_mutex_unlock(_mutex);
5876 assert_status(status == 0, status, "invariant");
5877 // Paranoia to ensure our locked and lock-free paths interact
5878 // correctly with each other and Java-level accesses.
5879 OrderAccess::fence();
5880
5881 // If externally suspended while waiting, re-suspend
5882 if (jt->handle_special_suspend_equivalent_condition()) {
5883 jt->java_suspend_self();
5884 }
5885 }
5886
5887 void Parker::unpark() {
5888 int status = pthread_mutex_lock(_mutex);
5889 assert_status(status == 0, status, "invariant");
5890 const int s = _counter;
5891 _counter = 1;
5892 // must capture correct index before unlocking
5893 int index = _cur_index;
5894 status = pthread_mutex_unlock(_mutex);
5895 assert_status(status == 0, status, "invariant");
5896 if (s < 1 && index != -1) {
5897 // thread is definitely parked
5898 status = pthread_cond_signal(&_cond[index]);
5899 assert_status(status == 0, status, "invariant");
5900 }
5901 }
5902
5903
5904 extern char** environ;
5905
5906 // Run the specified command in a separate process. Return its exit value,
5907 // or -1 on failure (e.g. can't fork a new process).
5908 // Unlike system(), this function can be called from signal handler. It
5909 // doesn't block SIGINT et al.
5910 int os::fork_and_exec(char* cmd) {
5911 const char * argv[4] = {"sh", "-c", cmd, NULL};
5912
5913 pid_t pid = fork();
5914
5915 if (pid < 0) {
5916 // fork failed
5917 return -1;
5918
5919 } else if (pid == 0) {
5920 // child process
5921
5922 execve("/bin/sh", (char* const*)argv, environ);
5923
5924 // execve failed
5925 _exit(-1);
5926
5927 } else {
5928 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5929 // care about the actual exit code, for now.
5930
5931 int status;
5932
5933 // Wait for the child process to exit. This returns immediately if
5934 // the child has already exited. */
5935 while (waitpid(pid, &status, 0) < 0) {
5936 switch (errno) {
5937 case ECHILD: return 0;
5938 case EINTR: break;
5939 default: return -1;
5940 }
5941 }
5942
5943 if (WIFEXITED(status)) {
5944 // The child exited normally; get its exit code.
5945 return WEXITSTATUS(status);
5946 } else if (WIFSIGNALED(status)) {
5947 // The child exited because of a signal
5948 // The best value to return is 0x80 + signal number,
5949 // because that is what all Unix shells do, and because
5950 // it allows callers to distinguish between process exit and
5951 // process death by signal.
5952 return 0x80 + WTERMSIG(status);
5953 } else {
5954 // Unknown exit code; pass it through
5955 return status;
5956 }
5957 }
5958 }
5959
5960 // is_headless_jre()
5961 //
5962 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5963 // in order to report if we are running in a headless jre
5964 //
5965 // Since JDK8 xawt/libmawt.so was moved into the same directory
5966 // as libawt.so, and renamed libawt_xawt.so
5967 //
5968 bool os::is_headless_jre() {
5969 struct stat statbuf;
5970 char buf[MAXPATHLEN];
5971 char libmawtpath[MAXPATHLEN];
5972 const char *xawtstr = "/xawt/libmawt.so";
5973 const char *new_xawtstr = "/libawt_xawt.so";
5974 char *p;
5975
5976 // Get path to libjvm.so
5977 os::jvm_path(buf, sizeof(buf));
5978
5979 // Get rid of libjvm.so
5980 p = strrchr(buf, '/');
5981 if (p == NULL) {
5982 return false;
5983 } else {
5984 *p = '\0';
5985 }
5986
5987 // Get rid of client or server
5988 p = strrchr(buf, '/');
5989 if (p == NULL) {
5990 return false;
5991 } else {
5992 *p = '\0';
5993 }
5994
5995 // check xawt/libmawt.so
5996 strcpy(libmawtpath, buf);
5997 strcat(libmawtpath, xawtstr);
5998 if (::stat(libmawtpath, &statbuf) == 0) return false;
5999
6000 // check libawt_xawt.so
6001 strcpy(libmawtpath, buf);
6002 strcat(libmawtpath, new_xawtstr);
6003 if (::stat(libmawtpath, &statbuf) == 0) return false;
6004
6005 return true;
6006 }
6007
6008 // Get the default path to the core file
6009 // Returns the length of the string
6010 int os::get_core_path(char* buffer, size_t bufferSize) {
6011 /*
6012 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
6013 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
6014 */
6015 const int core_pattern_len = 129;
6016 char core_pattern[core_pattern_len] = {0};
6017
6018 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
6019 if (core_pattern_file == -1) {
6020 return -1;
6021 }
6022
6023 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
6024 ::close(core_pattern_file);
6025 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
6026 return -1;
6027 }
6028 if (core_pattern[ret-1] == '\n') {
6029 core_pattern[ret-1] = '\0';
6030 } else {
6031 core_pattern[ret] = '\0';
6032 }
6033
6034 char *pid_pos = strstr(core_pattern, "%p");
6035 int written;
6036
6037 if (core_pattern[0] == '/') {
6038 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6039 } else {
6040 char cwd[PATH_MAX];
6041
6042 const char* p = get_current_directory(cwd, PATH_MAX);
6043 if (p == NULL) {
6044 return -1;
6045 }
6046
6047 if (core_pattern[0] == '|') {
6048 written = jio_snprintf(buffer, bufferSize,
6049 "\"%s\" (or dumping to %s/core.%d)",
6050 &core_pattern[1], p, current_process_id());
6051 } else {
6052 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6053 }
6054 }
6055
6056 if (written < 0) {
6057 return -1;
6058 }
6059
6060 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6061 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6062
6063 if (core_uses_pid_file != -1) {
6064 char core_uses_pid = 0;
6065 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6066 ::close(core_uses_pid_file);
6067
6068 if (core_uses_pid == '1') {
6069 jio_snprintf(buffer + written, bufferSize - written,
6070 ".%d", current_process_id());
6071 }
6072 }
6073 }
6074
6075 return strlen(buffer);
6076 }
6077
6078 bool os::start_debugging(char *buf, int buflen) {
6079 int len = (int)strlen(buf);
6080 char *p = &buf[len];
6081
6082 jio_snprintf(p, buflen-len,
6083 "\n\n"
6084 "Do you want to debug the problem?\n\n"
6085 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6086 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6087 "Otherwise, press RETURN to abort...",
6088 os::current_process_id(), os::current_process_id(),
6089 os::current_thread_id(), os::current_thread_id());
6090
6091 bool yes = os::message_box("Unexpected Error", buf);
6092
6093 if (yes) {
6094 // yes, user asked VM to launch debugger
6095 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6096 os::current_process_id(), os::current_process_id());
6097
6098 os::fork_and_exec(buf);
6099 yes = false;
6100 }
6101 return yes;
6102 }
6103
6104 static inline struct timespec get_mtime(const char* filename) {
6105 struct stat st;
6106 int ret = os::stat(filename, &st);
6107 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
6108 return st.st_mtim;
6109 }
6110
6111 int os::compare_file_modified_times(const char* file1, const char* file2) {
6112 struct timespec filetime1 = get_mtime(file1);
6113 struct timespec filetime2 = get_mtime(file2);
6114 int diff = filetime1.tv_sec - filetime2.tv_sec;
6115 if (diff == 0) {
6116 return filetime1.tv_nsec - filetime2.tv_nsec;
6117 }
6118 return diff;
6119 }
6120
6121 /////////////// Unit tests ///////////////
6122
6123 #ifndef PRODUCT
6124
6125 #define test_log(...) \
6126 do { \
6127 if (VerboseInternalVMTests) { \
6128 tty->print_cr(__VA_ARGS__); \
6129 tty->flush(); \
6130 } \
6131 } while (false)
6132
6133 class TestReserveMemorySpecial : AllStatic {
6134 public:
6135 static void small_page_write(void* addr, size_t size) {
6136 size_t page_size = os::vm_page_size();
6137
6138 char* end = (char*)addr + size;
6139 for (char* p = (char*)addr; p < end; p += page_size) {
6140 *p = 1;
6141 }
6142 }
6143
6144 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6145 if (!UseHugeTLBFS) {
6146 return;
6147 }
6148
6149 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6150
6151 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6152
6153 if (addr != NULL) {
6154 small_page_write(addr, size);
6155
6156 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6157 }
6158 }
6159
6160 static void test_reserve_memory_special_huge_tlbfs_only() {
6161 if (!UseHugeTLBFS) {
6162 return;
6163 }
6164
6165 size_t lp = os::large_page_size();
6166
6167 for (size_t size = lp; size <= lp * 10; size += lp) {
6168 test_reserve_memory_special_huge_tlbfs_only(size);
6169 }
6170 }
6171
6172 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6173 size_t lp = os::large_page_size();
6174 size_t ag = os::vm_allocation_granularity();
6175
6176 // sizes to test
6177 const size_t sizes[] = {
6178 lp, lp + ag, lp + lp / 2, lp * 2,
6179 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6180 lp * 10, lp * 10 + lp / 2
6181 };
6182 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6183
6184 // For each size/alignment combination, we test three scenarios:
6185 // 1) with req_addr == NULL
6186 // 2) with a non-null req_addr at which we expect to successfully allocate
6187 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6188 // expect the allocation to either fail or to ignore req_addr
6189
6190 // Pre-allocate two areas; they shall be as large as the largest allocation
6191 // and aligned to the largest alignment we will be testing.
6192 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6193 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6194 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6195 -1, 0);
6196 assert(mapping1 != MAP_FAILED, "should work");
6197
6198 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6199 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6200 -1, 0);
6201 assert(mapping2 != MAP_FAILED, "should work");
6202
6203 // Unmap the first mapping, but leave the second mapping intact: the first
6204 // mapping will serve as a value for a "good" req_addr (case 2). The second
6205 // mapping, still intact, as "bad" req_addr (case 3).
6206 ::munmap(mapping1, mapping_size);
6207
6208 // Case 1
6209 test_log("%s, req_addr NULL:", __FUNCTION__);
6210 test_log("size align result");
6211
6212 for (int i = 0; i < num_sizes; i++) {
6213 const size_t size = sizes[i];
6214 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6215 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6216 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6217 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6218 if (p != NULL) {
6219 assert(is_ptr_aligned(p, alignment), "must be");
6220 small_page_write(p, size);
6221 os::Linux::release_memory_special_huge_tlbfs(p, size);
6222 }
6223 }
6224 }
6225
6226 // Case 2
6227 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6228 test_log("size align req_addr result");
6229
6230 for (int i = 0; i < num_sizes; i++) {
6231 const size_t size = sizes[i];
6232 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6233 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6234 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6235 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6236 size, alignment, p2i(req_addr), p2i(p),
6237 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6238 if (p != NULL) {
6239 assert(p == req_addr, "must be");
6240 small_page_write(p, size);
6241 os::Linux::release_memory_special_huge_tlbfs(p, size);
6242 }
6243 }
6244 }
6245
6246 // Case 3
6247 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6248 test_log("size align req_addr result");
6249
6250 for (int i = 0; i < num_sizes; i++) {
6251 const size_t size = sizes[i];
6252 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6253 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6254 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6255 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6256 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6257 // as the area around req_addr contains already existing mappings, the API should always
6258 // return NULL (as per contract, it cannot return another address)
6259 assert(p == NULL, "must be");
6260 }
6261 }
6262
6263 ::munmap(mapping2, mapping_size);
6264
6265 }
6266
6267 static void test_reserve_memory_special_huge_tlbfs() {
6268 if (!UseHugeTLBFS) {
6269 return;
6270 }
6271
6272 test_reserve_memory_special_huge_tlbfs_only();
6273 test_reserve_memory_special_huge_tlbfs_mixed();
6274 }
6275
6276 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6277 if (!UseSHM) {
6278 return;
6279 }
6280
6281 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6282
6283 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6284
6285 if (addr != NULL) {
6286 assert(is_ptr_aligned(addr, alignment), "Check");
6287 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6288
6289 small_page_write(addr, size);
6290
6291 os::Linux::release_memory_special_shm(addr, size);
6292 }
6293 }
6294
6295 static void test_reserve_memory_special_shm() {
6296 size_t lp = os::large_page_size();
6297 size_t ag = os::vm_allocation_granularity();
6298
6299 for (size_t size = ag; size < lp * 3; size += ag) {
6300 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6301 test_reserve_memory_special_shm(size, alignment);
6302 }
6303 }
6304 }
6305
6306 static void test() {
6307 test_reserve_memory_special_huge_tlbfs();
6308 test_reserve_memory_special_shm();
6309 }
6310 };
6311
6312 void TestReserveMemorySpecial_test() {
6313 TestReserveMemorySpecial::test();
6314 }
6315
6316 #endif