1 /*
2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "logging/log.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_linux.inline.hpp"
40 #include "os_share_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/extendedPC.hpp"
47 #include "runtime/globals.hpp"
48 #include "runtime/interfaceSupport.hpp"
49 #include "runtime/init.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "runtime/objectMonitor.hpp"
54 #include "runtime/orderAccess.inline.hpp"
55 #include "runtime/osThread.hpp"
56 #include "runtime/perfMemory.hpp"
57 #include "runtime/sharedRuntime.hpp"
58 #include "runtime/statSampler.hpp"
59 #include "runtime/stubRoutines.hpp"
60 #include "runtime/thread.inline.hpp"
61 #include "runtime/threadCritical.hpp"
62 #include "runtime/timer.hpp"
63 #include "semaphore_posix.hpp"
64 #include "services/attachListener.hpp"
65 #include "services/memTracker.hpp"
66 #include "services/runtimeService.hpp"
67 #include "utilities/decoder.hpp"
68 #include "utilities/defaultStream.hpp"
69 #include "utilities/events.hpp"
70 #include "utilities/elfFile.hpp"
71 #include "utilities/growableArray.hpp"
72 #include "utilities/macros.hpp"
73 #include "utilities/vmError.hpp"
74
75 // put OS-includes here
76 # include <sys/types.h>
77 # include <sys/mman.h>
78 # include <sys/stat.h>
79 # include <sys/select.h>
80 # include <pthread.h>
81 # include <signal.h>
82 # include <errno.h>
83 # include <dlfcn.h>
84 # include <stdio.h>
85 # include <unistd.h>
86 # include <sys/resource.h>
87 # include <pthread.h>
88 # include <sys/stat.h>
89 # include <sys/time.h>
90 # include <sys/times.h>
91 # include <sys/utsname.h>
92 # include <sys/socket.h>
93 # include <sys/wait.h>
94 # include <pwd.h>
95 # include <poll.h>
96 # include <semaphore.h>
97 # include <fcntl.h>
98 # include <string.h>
99 # include <syscall.h>
100 # include <sys/sysinfo.h>
101 # include <gnu/libc-version.h>
102 # include <sys/ipc.h>
103 # include <sys/shm.h>
104 # include <link.h>
105 # include <stdint.h>
106 # include <inttypes.h>
107 # include <sys/ioctl.h>
108
109 #ifndef _GNU_SOURCE
110 #define _GNU_SOURCE
111 #include <sched.h>
112 #undef _GNU_SOURCE
113 #else
114 #include <sched.h>
115 #endif
116
117 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
118 // getrusage() is prepared to handle the associated failure.
119 #ifndef RUSAGE_THREAD
120 #define RUSAGE_THREAD (1) /* only the calling thread */
121 #endif
122
123 #define MAX_PATH (2 * K)
124
125 #define MAX_SECS 100000000
126
127 // for timer info max values which include all bits
128 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
129
130 #define LARGEPAGES_BIT (1 << 6)
131 ////////////////////////////////////////////////////////////////////////////////
132 // global variables
133 julong os::Linux::_physical_memory = 0;
134
135 address os::Linux::_initial_thread_stack_bottom = NULL;
136 uintptr_t os::Linux::_initial_thread_stack_size = 0;
137
138 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
139 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
140 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
141 Mutex* os::Linux::_createThread_lock = NULL;
142 pthread_t os::Linux::_main_thread;
143 int os::Linux::_page_size = -1;
144 bool os::Linux::_supports_fast_thread_cpu_time = false;
145 uint32_t os::Linux::_os_version = 0;
146 const char * os::Linux::_glibc_version = NULL;
147 const char * os::Linux::_libpthread_version = NULL;
148 pthread_condattr_t os::Linux::_condattr[1];
149
150 static jlong initial_time_count=0;
151
152 static int clock_tics_per_sec = 100;
153
154 // For diagnostics to print a message once. see run_periodic_checks
155 static sigset_t check_signal_done;
156 static bool check_signals = true;
157
158 // Signal number used to suspend/resume a thread
159
160 // do not use any signal number less than SIGSEGV, see 4355769
161 static int SR_signum = SIGUSR2;
162 sigset_t SR_sigset;
163
164 // Declarations
165 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
166
167 // utility functions
168
169 static int SR_initialize();
170
171 julong os::available_memory() {
172 return Linux::available_memory();
173 }
174
175 julong os::Linux::available_memory() {
176 // values in struct sysinfo are "unsigned long"
177 struct sysinfo si;
178 sysinfo(&si);
179
180 return (julong)si.freeram * si.mem_unit;
181 }
182
183 julong os::physical_memory() {
184 return Linux::physical_memory();
185 }
186
187 // Return true if user is running as root.
188
189 bool os::have_special_privileges() {
190 static bool init = false;
191 static bool privileges = false;
192 if (!init) {
193 privileges = (getuid() != geteuid()) || (getgid() != getegid());
194 init = true;
195 }
196 return privileges;
197 }
198
199
200 #ifndef SYS_gettid
201 // i386: 224, ia64: 1105, amd64: 186, sparc 143
202 #ifdef __ia64__
203 #define SYS_gettid 1105
204 #else
205 #ifdef __i386__
206 #define SYS_gettid 224
207 #else
208 #ifdef __amd64__
209 #define SYS_gettid 186
210 #else
211 #ifdef __sparc__
212 #define SYS_gettid 143
213 #else
214 #error define gettid for the arch
215 #endif
216 #endif
217 #endif
218 #endif
219 #endif
220
221
222 // pid_t gettid()
223 //
224 // Returns the kernel thread id of the currently running thread. Kernel
225 // thread id is used to access /proc.
226 pid_t os::Linux::gettid() {
227 int rslt = syscall(SYS_gettid);
228 assert(rslt != -1, "must be."); // old linuxthreads implementation?
229 return (pid_t)rslt;
230 }
231
232 // Most versions of linux have a bug where the number of processors are
233 // determined by looking at the /proc file system. In a chroot environment,
234 // the system call returns 1. This causes the VM to act as if it is
235 // a single processor and elide locking (see is_MP() call).
236 static bool unsafe_chroot_detected = false;
237 static const char *unstable_chroot_error = "/proc file system not found.\n"
238 "Java may be unstable running multithreaded in a chroot "
239 "environment on Linux when /proc filesystem is not mounted.";
240
241 void os::Linux::initialize_system_info() {
242 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
243 if (processor_count() == 1) {
244 pid_t pid = os::Linux::gettid();
245 char fname[32];
246 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
247 FILE *fp = fopen(fname, "r");
248 if (fp == NULL) {
249 unsafe_chroot_detected = true;
250 } else {
251 fclose(fp);
252 }
253 }
254 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
255 assert(processor_count() > 0, "linux error");
256 }
257
258 void os::init_system_properties_values() {
259 // The next steps are taken in the product version:
260 //
261 // Obtain the JAVA_HOME value from the location of libjvm.so.
262 // This library should be located at:
263 // <JAVA_HOME>/lib/{client|server}/libjvm.so.
264 //
265 // If "/jre/lib/" appears at the right place in the path, then we
266 // assume libjvm.so is installed in a JDK and we use this path.
267 //
268 // Otherwise exit with message: "Could not create the Java virtual machine."
269 //
270 // The following extra steps are taken in the debugging version:
271 //
272 // If "/jre/lib/" does NOT appear at the right place in the path
273 // instead of exit check for $JAVA_HOME environment variable.
274 //
275 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
276 // then we append a fake suffix "hotspot/libjvm.so" to this path so
277 // it looks like libjvm.so is installed there
278 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
279 //
280 // Otherwise exit.
281 //
282 // Important note: if the location of libjvm.so changes this
283 // code needs to be changed accordingly.
284
285 // See ld(1):
286 // The linker uses the following search paths to locate required
287 // shared libraries:
288 // 1: ...
289 // ...
290 // 7: The default directories, normally /lib and /usr/lib.
291 #if defined(AMD64) || (defined(_LP64) && defined(SPARC)) || defined(PPC64) || defined(S390)
292 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
293 #else
294 #define DEFAULT_LIBPATH "/lib:/usr/lib"
295 #endif
296
297 // Base path of extensions installed on the system.
298 #define SYS_EXT_DIR "/usr/java/packages"
299 #define EXTENSIONS_DIR "/lib/ext"
300
301 // Buffer that fits several sprintfs.
302 // Note that the space for the colon and the trailing null are provided
303 // by the nulls included by the sizeof operator.
304 const size_t bufsize =
305 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
306 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
307 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
308
309 // sysclasspath, java_home, dll_dir
310 {
311 char *pslash;
312 os::jvm_path(buf, bufsize);
313
314 // Found the full path to libjvm.so.
315 // Now cut the path to <java_home>/jre if we can.
316 pslash = strrchr(buf, '/');
317 if (pslash != NULL) {
318 *pslash = '\0'; // Get rid of /libjvm.so.
319 }
320 pslash = strrchr(buf, '/');
321 if (pslash != NULL) {
322 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
323 }
324 Arguments::set_dll_dir(buf);
325
326 if (pslash != NULL) {
327 pslash = strrchr(buf, '/');
328 if (pslash != NULL) {
329 *pslash = '\0'; // Get rid of /lib.
330 }
331 }
332 Arguments::set_java_home(buf);
333 set_boot_path('/', ':');
334 }
335
336 // Where to look for native libraries.
337 //
338 // Note: Due to a legacy implementation, most of the library path
339 // is set in the launcher. This was to accomodate linking restrictions
340 // on legacy Linux implementations (which are no longer supported).
341 // Eventually, all the library path setting will be done here.
342 //
343 // However, to prevent the proliferation of improperly built native
344 // libraries, the new path component /usr/java/packages is added here.
345 // Eventually, all the library path setting will be done here.
346 {
347 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
348 // should always exist (until the legacy problem cited above is
349 // addressed).
350 const char *v = ::getenv("LD_LIBRARY_PATH");
351 const char *v_colon = ":";
352 if (v == NULL) { v = ""; v_colon = ""; }
353 // That's +1 for the colon and +1 for the trailing '\0'.
354 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
355 strlen(v) + 1 +
356 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + sizeof(DEFAULT_LIBPATH) + 1,
357 mtInternal);
358 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib:" DEFAULT_LIBPATH, v, v_colon);
359 Arguments::set_library_path(ld_library_path);
360 FREE_C_HEAP_ARRAY(char, ld_library_path);
361 }
362
363 // Extensions directories.
364 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
365 Arguments::set_ext_dirs(buf);
366
367 FREE_C_HEAP_ARRAY(char, buf);
368
369 #undef DEFAULT_LIBPATH
370 #undef SYS_EXT_DIR
371 #undef EXTENSIONS_DIR
372 }
373
374 ////////////////////////////////////////////////////////////////////////////////
375 // breakpoint support
376
377 void os::breakpoint() {
378 BREAKPOINT;
379 }
380
381 extern "C" void breakpoint() {
382 // use debugger to set breakpoint here
383 }
384
385 ////////////////////////////////////////////////////////////////////////////////
386 // signal support
387
388 debug_only(static bool signal_sets_initialized = false);
389 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
390
391 bool os::Linux::is_sig_ignored(int sig) {
392 struct sigaction oact;
393 sigaction(sig, (struct sigaction*)NULL, &oact);
394 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
395 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
396 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
397 return true;
398 } else {
399 return false;
400 }
401 }
402
403 void os::Linux::signal_sets_init() {
404 // Should also have an assertion stating we are still single-threaded.
405 assert(!signal_sets_initialized, "Already initialized");
406 // Fill in signals that are necessarily unblocked for all threads in
407 // the VM. Currently, we unblock the following signals:
408 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
409 // by -Xrs (=ReduceSignalUsage));
410 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
411 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
412 // the dispositions or masks wrt these signals.
413 // Programs embedding the VM that want to use the above signals for their
414 // own purposes must, at this time, use the "-Xrs" option to prevent
415 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
416 // (See bug 4345157, and other related bugs).
417 // In reality, though, unblocking these signals is really a nop, since
418 // these signals are not blocked by default.
419 sigemptyset(&unblocked_sigs);
420 sigemptyset(&allowdebug_blocked_sigs);
421 sigaddset(&unblocked_sigs, SIGILL);
422 sigaddset(&unblocked_sigs, SIGSEGV);
423 sigaddset(&unblocked_sigs, SIGBUS);
424 sigaddset(&unblocked_sigs, SIGFPE);
425 #if defined(PPC64)
426 sigaddset(&unblocked_sigs, SIGTRAP);
427 #endif
428 sigaddset(&unblocked_sigs, SR_signum);
429
430 if (!ReduceSignalUsage) {
431 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
432 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
433 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
434 }
435 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
436 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
437 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
438 }
439 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
440 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
441 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
442 }
443 }
444 // Fill in signals that are blocked by all but the VM thread.
445 sigemptyset(&vm_sigs);
446 if (!ReduceSignalUsage) {
447 sigaddset(&vm_sigs, BREAK_SIGNAL);
448 }
449 debug_only(signal_sets_initialized = true);
450
451 }
452
453 // These are signals that are unblocked while a thread is running Java.
454 // (For some reason, they get blocked by default.)
455 sigset_t* os::Linux::unblocked_signals() {
456 assert(signal_sets_initialized, "Not initialized");
457 return &unblocked_sigs;
458 }
459
460 // These are the signals that are blocked while a (non-VM) thread is
461 // running Java. Only the VM thread handles these signals.
462 sigset_t* os::Linux::vm_signals() {
463 assert(signal_sets_initialized, "Not initialized");
464 return &vm_sigs;
465 }
466
467 // These are signals that are blocked during cond_wait to allow debugger in
468 sigset_t* os::Linux::allowdebug_blocked_signals() {
469 assert(signal_sets_initialized, "Not initialized");
470 return &allowdebug_blocked_sigs;
471 }
472
473 void os::Linux::hotspot_sigmask(Thread* thread) {
474
475 //Save caller's signal mask before setting VM signal mask
476 sigset_t caller_sigmask;
477 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
478
479 OSThread* osthread = thread->osthread();
480 osthread->set_caller_sigmask(caller_sigmask);
481
482 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
483
484 if (!ReduceSignalUsage) {
485 if (thread->is_VM_thread()) {
486 // Only the VM thread handles BREAK_SIGNAL ...
487 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
488 } else {
489 // ... all other threads block BREAK_SIGNAL
490 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
491 }
492 }
493 }
494
495 //////////////////////////////////////////////////////////////////////////////
496 // detecting pthread library
497
498 void os::Linux::libpthread_init() {
499 // Save glibc and pthread version strings.
500 #if !defined(_CS_GNU_LIBC_VERSION) || \
501 !defined(_CS_GNU_LIBPTHREAD_VERSION)
502 #error "glibc too old (< 2.3.2)"
503 #endif
504
505 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
506 assert(n > 0, "cannot retrieve glibc version");
507 char *str = (char *)malloc(n, mtInternal);
508 confstr(_CS_GNU_LIBC_VERSION, str, n);
509 os::Linux::set_glibc_version(str);
510
511 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
512 assert(n > 0, "cannot retrieve pthread version");
513 str = (char *)malloc(n, mtInternal);
514 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
515 os::Linux::set_libpthread_version(str);
516 }
517
518 /////////////////////////////////////////////////////////////////////////////
519 // thread stack expansion
520
521 // os::Linux::manually_expand_stack() takes care of expanding the thread
522 // stack. Note that this is normally not needed: pthread stacks allocate
523 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
524 // committed. Therefore it is not necessary to expand the stack manually.
525 //
526 // Manually expanding the stack was historically needed on LinuxThreads
527 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
528 // it is kept to deal with very rare corner cases:
529 //
530 // For one, user may run the VM on an own implementation of threads
531 // whose stacks are - like the old LinuxThreads - implemented using
532 // mmap(MAP_GROWSDOWN).
533 //
534 // Also, this coding may be needed if the VM is running on the primordial
535 // thread. Normally we avoid running on the primordial thread; however,
536 // user may still invoke the VM on the primordial thread.
537 //
538 // The following historical comment describes the details about running
539 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
540
541
542 // Force Linux kernel to expand current thread stack. If "bottom" is close
543 // to the stack guard, caller should block all signals.
544 //
545 // MAP_GROWSDOWN:
546 // A special mmap() flag that is used to implement thread stacks. It tells
547 // kernel that the memory region should extend downwards when needed. This
548 // allows early versions of LinuxThreads to only mmap the first few pages
549 // when creating a new thread. Linux kernel will automatically expand thread
550 // stack as needed (on page faults).
551 //
552 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
553 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
554 // region, it's hard to tell if the fault is due to a legitimate stack
555 // access or because of reading/writing non-exist memory (e.g. buffer
556 // overrun). As a rule, if the fault happens below current stack pointer,
557 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
558 // application (see Linux kernel fault.c).
559 //
560 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
561 // stack overflow detection.
562 //
563 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
564 // not use MAP_GROWSDOWN.
565 //
566 // To get around the problem and allow stack banging on Linux, we need to
567 // manually expand thread stack after receiving the SIGSEGV.
568 //
569 // There are two ways to expand thread stack to address "bottom", we used
570 // both of them in JVM before 1.5:
571 // 1. adjust stack pointer first so that it is below "bottom", and then
572 // touch "bottom"
573 // 2. mmap() the page in question
574 //
575 // Now alternate signal stack is gone, it's harder to use 2. For instance,
576 // if current sp is already near the lower end of page 101, and we need to
577 // call mmap() to map page 100, it is possible that part of the mmap() frame
578 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
579 // That will destroy the mmap() frame and cause VM to crash.
580 //
581 // The following code works by adjusting sp first, then accessing the "bottom"
582 // page to force a page fault. Linux kernel will then automatically expand the
583 // stack mapping.
584 //
585 // _expand_stack_to() assumes its frame size is less than page size, which
586 // should always be true if the function is not inlined.
587
588 static void NOINLINE _expand_stack_to(address bottom) {
589 address sp;
590 size_t size;
591 volatile char *p;
592
593 // Adjust bottom to point to the largest address within the same page, it
594 // gives us a one-page buffer if alloca() allocates slightly more memory.
595 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
596 bottom += os::Linux::page_size() - 1;
597
598 // sp might be slightly above current stack pointer; if that's the case, we
599 // will alloca() a little more space than necessary, which is OK. Don't use
600 // os::current_stack_pointer(), as its result can be slightly below current
601 // stack pointer, causing us to not alloca enough to reach "bottom".
602 sp = (address)&sp;
603
604 if (sp > bottom) {
605 size = sp - bottom;
606 p = (volatile char *)alloca(size);
607 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
608 p[0] = '\0';
609 }
610 }
611
612 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
613 assert(t!=NULL, "just checking");
614 assert(t->osthread()->expanding_stack(), "expand should be set");
615 assert(t->stack_base() != NULL, "stack_base was not initialized");
616
617 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
618 sigset_t mask_all, old_sigset;
619 sigfillset(&mask_all);
620 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
621 _expand_stack_to(addr);
622 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
623 return true;
624 }
625 return false;
626 }
627
628 //////////////////////////////////////////////////////////////////////////////
629 // create new thread
630
631 // Thread start routine for all newly created threads
632 static void *thread_native_entry(Thread *thread) {
633 // Try to randomize the cache line index of hot stack frames.
634 // This helps when threads of the same stack traces evict each other's
635 // cache lines. The threads can be either from the same JVM instance, or
636 // from different JVM instances. The benefit is especially true for
637 // processors with hyperthreading technology.
638 static int counter = 0;
639 int pid = os::current_process_id();
640 alloca(((pid ^ counter++) & 7) * 128);
641
642 thread->initialize_thread_current();
643
644 OSThread* osthread = thread->osthread();
645 Monitor* sync = osthread->startThread_lock();
646
647 osthread->set_thread_id(os::current_thread_id());
648
649 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
650 os::current_thread_id(), (uintx) pthread_self());
651
652 if (UseNUMA) {
653 int lgrp_id = os::numa_get_group_id();
654 if (lgrp_id != -1) {
655 thread->set_lgrp_id(lgrp_id);
656 }
657 }
658 // initialize signal mask for this thread
659 os::Linux::hotspot_sigmask(thread);
660
661 // initialize floating point control register
662 os::Linux::init_thread_fpu_state();
663
664 // handshaking with parent thread
665 {
666 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
667
668 // notify parent thread
669 osthread->set_state(INITIALIZED);
670 sync->notify_all();
671
672 // wait until os::start_thread()
673 while (osthread->get_state() == INITIALIZED) {
674 sync->wait(Mutex::_no_safepoint_check_flag);
675 }
676 }
677
678 // call one more level start routine
679 thread->run();
680
681 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
682 os::current_thread_id(), (uintx) pthread_self());
683
684 // If a thread has not deleted itself ("delete this") as part of its
685 // termination sequence, we have to ensure thread-local-storage is
686 // cleared before we actually terminate. No threads should ever be
687 // deleted asynchronously with respect to their termination.
688 if (Thread::current_or_null_safe() != NULL) {
689 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
690 thread->clear_thread_current();
691 }
692
693 return 0;
694 }
695
696 bool os::create_thread(Thread* thread, ThreadType thr_type,
697 size_t req_stack_size) {
698 assert(thread->osthread() == NULL, "caller responsible");
699
700 // Allocate the OSThread object
701 OSThread* osthread = new OSThread(NULL, NULL);
702 if (osthread == NULL) {
703 return false;
704 }
705
706 // set the correct thread state
707 osthread->set_thread_type(thr_type);
708
709 // Initial state is ALLOCATED but not INITIALIZED
710 osthread->set_state(ALLOCATED);
711
712 thread->set_osthread(osthread);
713
714 // init thread attributes
715 pthread_attr_t attr;
716 pthread_attr_init(&attr);
717 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
718
719 // Calculate stack size if it's not specified by caller.
720 size_t stack_size = os::Posix::get_initial_stack_size(thr_type, req_stack_size);
721 // In the Linux NPTL pthread implementation the guard size mechanism
722 // is not implemented properly. The posix standard requires adding
723 // the size of the guard pages to the stack size, instead Linux
724 // takes the space out of 'stacksize'. Thus we adapt the requested
725 // stack_size by the size of the guard pages to mimick proper
726 // behaviour.
727 stack_size = align_size_up(stack_size + os::Linux::default_guard_size(thr_type), vm_page_size());
728 pthread_attr_setstacksize(&attr, stack_size);
729
730 // Configure glibc guard page.
731 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
732
733 ThreadState state;
734
735 {
736 pthread_t tid;
737 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
738
739 char buf[64];
740 if (ret == 0) {
741 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
742 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
743 } else {
744 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
745 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
746 }
747
748 pthread_attr_destroy(&attr);
749
750 if (ret != 0) {
751 // Need to clean up stuff we've allocated so far
752 thread->set_osthread(NULL);
753 delete osthread;
754 return false;
755 }
756
757 // Store pthread info into the OSThread
758 osthread->set_pthread_id(tid);
759
760 // Wait until child thread is either initialized or aborted
761 {
762 Monitor* sync_with_child = osthread->startThread_lock();
763 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
764 while ((state = osthread->get_state()) == ALLOCATED) {
765 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
766 }
767 }
768 }
769
770 // Aborted due to thread limit being reached
771 if (state == ZOMBIE) {
772 thread->set_osthread(NULL);
773 delete osthread;
774 return false;
775 }
776
777 // The thread is returned suspended (in state INITIALIZED),
778 // and is started higher up in the call chain
779 assert(state == INITIALIZED, "race condition");
780 return true;
781 }
782
783 /////////////////////////////////////////////////////////////////////////////
784 // attach existing thread
785
786 // bootstrap the main thread
787 bool os::create_main_thread(JavaThread* thread) {
788 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
789 return create_attached_thread(thread);
790 }
791
792 bool os::create_attached_thread(JavaThread* thread) {
793 #ifdef ASSERT
794 thread->verify_not_published();
795 #endif
796
797 // Allocate the OSThread object
798 OSThread* osthread = new OSThread(NULL, NULL);
799
800 if (osthread == NULL) {
801 return false;
802 }
803
804 // Store pthread info into the OSThread
805 osthread->set_thread_id(os::Linux::gettid());
806 osthread->set_pthread_id(::pthread_self());
807
808 // initialize floating point control register
809 os::Linux::init_thread_fpu_state();
810
811 // Initial thread state is RUNNABLE
812 osthread->set_state(RUNNABLE);
813
814 thread->set_osthread(osthread);
815
816 if (UseNUMA) {
817 int lgrp_id = os::numa_get_group_id();
818 if (lgrp_id != -1) {
819 thread->set_lgrp_id(lgrp_id);
820 }
821 }
822
823 if (os::Linux::is_initial_thread()) {
824 // If current thread is initial thread, its stack is mapped on demand,
825 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
826 // the entire stack region to avoid SEGV in stack banging.
827 // It is also useful to get around the heap-stack-gap problem on SuSE
828 // kernel (see 4821821 for details). We first expand stack to the top
829 // of yellow zone, then enable stack yellow zone (order is significant,
830 // enabling yellow zone first will crash JVM on SuSE Linux), so there
831 // is no gap between the last two virtual memory regions.
832
833 JavaThread *jt = (JavaThread *)thread;
834 address addr = jt->stack_reserved_zone_base();
835 assert(addr != NULL, "initialization problem?");
836 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
837
838 osthread->set_expanding_stack();
839 os::Linux::manually_expand_stack(jt, addr);
840 osthread->clear_expanding_stack();
841 }
842
843 // initialize signal mask for this thread
844 // and save the caller's signal mask
845 os::Linux::hotspot_sigmask(thread);
846
847 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
848 os::current_thread_id(), (uintx) pthread_self());
849
850 return true;
851 }
852
853 void os::pd_start_thread(Thread* thread) {
854 OSThread * osthread = thread->osthread();
855 assert(osthread->get_state() != INITIALIZED, "just checking");
856 Monitor* sync_with_child = osthread->startThread_lock();
857 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
858 sync_with_child->notify();
859 }
860
861 // Free Linux resources related to the OSThread
862 void os::free_thread(OSThread* osthread) {
863 assert(osthread != NULL, "osthread not set");
864
865 // We are told to free resources of the argument thread,
866 // but we can only really operate on the current thread.
867 assert(Thread::current()->osthread() == osthread,
868 "os::free_thread but not current thread");
869
870 #ifdef ASSERT
871 sigset_t current;
872 sigemptyset(¤t);
873 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
874 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
875 #endif
876
877 // Restore caller's signal mask
878 sigset_t sigmask = osthread->caller_sigmask();
879 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
880
881 delete osthread;
882 }
883
884 //////////////////////////////////////////////////////////////////////////////
885 // initial thread
886
887 // Check if current thread is the initial thread, similar to Solaris thr_main.
888 bool os::Linux::is_initial_thread(void) {
889 char dummy;
890 // If called before init complete, thread stack bottom will be null.
891 // Can be called if fatal error occurs before initialization.
892 if (initial_thread_stack_bottom() == NULL) return false;
893 assert(initial_thread_stack_bottom() != NULL &&
894 initial_thread_stack_size() != 0,
895 "os::init did not locate initial thread's stack region");
896 if ((address)&dummy >= initial_thread_stack_bottom() &&
897 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
898 return true;
899 } else {
900 return false;
901 }
902 }
903
904 // Find the virtual memory area that contains addr
905 static bool find_vma(address addr, address* vma_low, address* vma_high) {
906 FILE *fp = fopen("/proc/self/maps", "r");
907 if (fp) {
908 address low, high;
909 while (!feof(fp)) {
910 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
911 if (low <= addr && addr < high) {
912 if (vma_low) *vma_low = low;
913 if (vma_high) *vma_high = high;
914 fclose(fp);
915 return true;
916 }
917 }
918 for (;;) {
919 int ch = fgetc(fp);
920 if (ch == EOF || ch == (int)'\n') break;
921 }
922 }
923 fclose(fp);
924 }
925 return false;
926 }
927
928 // Locate initial thread stack. This special handling of initial thread stack
929 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
930 // bogus value for initial thread.
931 void os::Linux::capture_initial_stack(size_t max_size) {
932 // stack size is the easy part, get it from RLIMIT_STACK
933 struct rlimit rlim;
934 getrlimit(RLIMIT_STACK, &rlim);
935 size_t stack_size = rlim.rlim_cur;
936
937 // 6308388: a bug in ld.so will relocate its own .data section to the
938 // lower end of primordial stack; reduce ulimit -s value a little bit
939 // so we won't install guard page on ld.so's data section.
940 stack_size -= 2 * page_size();
941
942 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
943 // 7.1, in both cases we will get 2G in return value.
944 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
945 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
946 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
947 // in case other parts in glibc still assumes 2M max stack size.
948 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
949 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
950 if (stack_size > 2 * K * K IA64_ONLY(*2)) {
951 stack_size = 2 * K * K IA64_ONLY(*2);
952 }
953 // Try to figure out where the stack base (top) is. This is harder.
954 //
955 // When an application is started, glibc saves the initial stack pointer in
956 // a global variable "__libc_stack_end", which is then used by system
957 // libraries. __libc_stack_end should be pretty close to stack top. The
958 // variable is available since the very early days. However, because it is
959 // a private interface, it could disappear in the future.
960 //
961 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
962 // to __libc_stack_end, it is very close to stack top, but isn't the real
963 // stack top. Note that /proc may not exist if VM is running as a chroot
964 // program, so reading /proc/<pid>/stat could fail. Also the contents of
965 // /proc/<pid>/stat could change in the future (though unlikely).
966 //
967 // We try __libc_stack_end first. If that doesn't work, look for
968 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
969 // as a hint, which should work well in most cases.
970
971 uintptr_t stack_start;
972
973 // try __libc_stack_end first
974 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
975 if (p && *p) {
976 stack_start = *p;
977 } else {
978 // see if we can get the start_stack field from /proc/self/stat
979 FILE *fp;
980 int pid;
981 char state;
982 int ppid;
983 int pgrp;
984 int session;
985 int nr;
986 int tpgrp;
987 unsigned long flags;
988 unsigned long minflt;
989 unsigned long cminflt;
990 unsigned long majflt;
991 unsigned long cmajflt;
992 unsigned long utime;
993 unsigned long stime;
994 long cutime;
995 long cstime;
996 long prio;
997 long nice;
998 long junk;
999 long it_real;
1000 uintptr_t start;
1001 uintptr_t vsize;
1002 intptr_t rss;
1003 uintptr_t rsslim;
1004 uintptr_t scodes;
1005 uintptr_t ecode;
1006 int i;
1007
1008 // Figure what the primordial thread stack base is. Code is inspired
1009 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1010 // followed by command name surrounded by parentheses, state, etc.
1011 char stat[2048];
1012 int statlen;
1013
1014 fp = fopen("/proc/self/stat", "r");
1015 if (fp) {
1016 statlen = fread(stat, 1, 2047, fp);
1017 stat[statlen] = '\0';
1018 fclose(fp);
1019
1020 // Skip pid and the command string. Note that we could be dealing with
1021 // weird command names, e.g. user could decide to rename java launcher
1022 // to "java 1.4.2 :)", then the stat file would look like
1023 // 1234 (java 1.4.2 :)) R ... ...
1024 // We don't really need to know the command string, just find the last
1025 // occurrence of ")" and then start parsing from there. See bug 4726580.
1026 char * s = strrchr(stat, ')');
1027
1028 i = 0;
1029 if (s) {
1030 // Skip blank chars
1031 do { s++; } while (s && isspace(*s));
1032
1033 #define _UFM UINTX_FORMAT
1034 #define _DFM INTX_FORMAT
1035
1036 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1037 // 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
1038 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,
1039 &state, // 3 %c
1040 &ppid, // 4 %d
1041 &pgrp, // 5 %d
1042 &session, // 6 %d
1043 &nr, // 7 %d
1044 &tpgrp, // 8 %d
1045 &flags, // 9 %lu
1046 &minflt, // 10 %lu
1047 &cminflt, // 11 %lu
1048 &majflt, // 12 %lu
1049 &cmajflt, // 13 %lu
1050 &utime, // 14 %lu
1051 &stime, // 15 %lu
1052 &cutime, // 16 %ld
1053 &cstime, // 17 %ld
1054 &prio, // 18 %ld
1055 &nice, // 19 %ld
1056 &junk, // 20 %ld
1057 &it_real, // 21 %ld
1058 &start, // 22 UINTX_FORMAT
1059 &vsize, // 23 UINTX_FORMAT
1060 &rss, // 24 INTX_FORMAT
1061 &rsslim, // 25 UINTX_FORMAT
1062 &scodes, // 26 UINTX_FORMAT
1063 &ecode, // 27 UINTX_FORMAT
1064 &stack_start); // 28 UINTX_FORMAT
1065 }
1066
1067 #undef _UFM
1068 #undef _DFM
1069
1070 if (i != 28 - 2) {
1071 assert(false, "Bad conversion from /proc/self/stat");
1072 // product mode - assume we are the initial thread, good luck in the
1073 // embedded case.
1074 warning("Can't detect initial thread stack location - bad conversion");
1075 stack_start = (uintptr_t) &rlim;
1076 }
1077 } else {
1078 // For some reason we can't open /proc/self/stat (for example, running on
1079 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1080 // most cases, so don't abort:
1081 warning("Can't detect initial thread stack location - no /proc/self/stat");
1082 stack_start = (uintptr_t) &rlim;
1083 }
1084 }
1085
1086 // Now we have a pointer (stack_start) very close to the stack top, the
1087 // next thing to do is to figure out the exact location of stack top. We
1088 // can find out the virtual memory area that contains stack_start by
1089 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1090 // and its upper limit is the real stack top. (again, this would fail if
1091 // running inside chroot, because /proc may not exist.)
1092
1093 uintptr_t stack_top;
1094 address low, high;
1095 if (find_vma((address)stack_start, &low, &high)) {
1096 // success, "high" is the true stack top. (ignore "low", because initial
1097 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1098 stack_top = (uintptr_t)high;
1099 } else {
1100 // failed, likely because /proc/self/maps does not exist
1101 warning("Can't detect initial thread stack location - find_vma failed");
1102 // best effort: stack_start is normally within a few pages below the real
1103 // stack top, use it as stack top, and reduce stack size so we won't put
1104 // guard page outside stack.
1105 stack_top = stack_start;
1106 stack_size -= 16 * page_size();
1107 }
1108
1109 // stack_top could be partially down the page so align it
1110 stack_top = align_size_up(stack_top, page_size());
1111
1112 if (max_size && stack_size > max_size) {
1113 _initial_thread_stack_size = max_size;
1114 } else {
1115 _initial_thread_stack_size = stack_size;
1116 }
1117
1118 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1119 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1120 }
1121
1122 ////////////////////////////////////////////////////////////////////////////////
1123 // time support
1124
1125 // Time since start-up in seconds to a fine granularity.
1126 // Used by VMSelfDestructTimer and the MemProfiler.
1127 double os::elapsedTime() {
1128
1129 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1130 }
1131
1132 jlong os::elapsed_counter() {
1133 return javaTimeNanos() - initial_time_count;
1134 }
1135
1136 jlong os::elapsed_frequency() {
1137 return NANOSECS_PER_SEC; // nanosecond resolution
1138 }
1139
1140 bool os::supports_vtime() { return true; }
1141 bool os::enable_vtime() { return false; }
1142 bool os::vtime_enabled() { return false; }
1143
1144 double os::elapsedVTime() {
1145 struct rusage usage;
1146 int retval = getrusage(RUSAGE_THREAD, &usage);
1147 if (retval == 0) {
1148 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);
1149 } else {
1150 // better than nothing, but not much
1151 return elapsedTime();
1152 }
1153 }
1154
1155 jlong os::javaTimeMillis() {
1156 timeval time;
1157 int status = gettimeofday(&time, NULL);
1158 assert(status != -1, "linux error");
1159 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1160 }
1161
1162 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1163 timeval time;
1164 int status = gettimeofday(&time, NULL);
1165 assert(status != -1, "linux error");
1166 seconds = jlong(time.tv_sec);
1167 nanos = jlong(time.tv_usec) * 1000;
1168 }
1169
1170
1171 #ifndef CLOCK_MONOTONIC
1172 #define CLOCK_MONOTONIC (1)
1173 #endif
1174
1175 void os::Linux::clock_init() {
1176 // we do dlopen's in this particular order due to bug in linux
1177 // dynamical loader (see 6348968) leading to crash on exit
1178 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1179 if (handle == NULL) {
1180 handle = dlopen("librt.so", RTLD_LAZY);
1181 }
1182
1183 if (handle) {
1184 int (*clock_getres_func)(clockid_t, struct timespec*) =
1185 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1186 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1187 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1188 if (clock_getres_func && clock_gettime_func) {
1189 // See if monotonic clock is supported by the kernel. Note that some
1190 // early implementations simply return kernel jiffies (updated every
1191 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1192 // for nano time (though the monotonic property is still nice to have).
1193 // It's fixed in newer kernels, however clock_getres() still returns
1194 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1195 // resolution for now. Hopefully as people move to new kernels, this
1196 // won't be a problem.
1197 struct timespec res;
1198 struct timespec tp;
1199 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1200 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1201 // yes, monotonic clock is supported
1202 _clock_gettime = clock_gettime_func;
1203 return;
1204 } else {
1205 // close librt if there is no monotonic clock
1206 dlclose(handle);
1207 }
1208 }
1209 }
1210 warning("No monotonic clock was available - timed services may " \
1211 "be adversely affected if the time-of-day clock changes");
1212 }
1213
1214 #ifndef SYS_clock_getres
1215 #if defined(X86) || defined(PPC64) || defined(S390)
1216 #define SYS_clock_getres AMD64_ONLY(229) IA32_ONLY(266) PPC64_ONLY(247) S390_ONLY(261)
1217 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1218 #else
1219 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1220 #define sys_clock_getres(x,y) -1
1221 #endif
1222 #else
1223 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1224 #endif
1225
1226 void os::Linux::fast_thread_clock_init() {
1227 if (!UseLinuxPosixThreadCPUClocks) {
1228 return;
1229 }
1230 clockid_t clockid;
1231 struct timespec tp;
1232 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1233 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1234
1235 // Switch to using fast clocks for thread cpu time if
1236 // the sys_clock_getres() returns 0 error code.
1237 // Note, that some kernels may support the current thread
1238 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1239 // returned by the pthread_getcpuclockid().
1240 // If the fast Posix clocks are supported then the sys_clock_getres()
1241 // must return at least tp.tv_sec == 0 which means a resolution
1242 // better than 1 sec. This is extra check for reliability.
1243
1244 if (pthread_getcpuclockid_func &&
1245 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1246 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1247 _supports_fast_thread_cpu_time = true;
1248 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1249 }
1250 }
1251
1252 jlong os::javaTimeNanos() {
1253 if (os::supports_monotonic_clock()) {
1254 struct timespec tp;
1255 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1256 assert(status == 0, "gettime error");
1257 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1258 return result;
1259 } else {
1260 timeval time;
1261 int status = gettimeofday(&time, NULL);
1262 assert(status != -1, "linux error");
1263 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1264 return 1000 * usecs;
1265 }
1266 }
1267
1268 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1269 if (os::supports_monotonic_clock()) {
1270 info_ptr->max_value = ALL_64_BITS;
1271
1272 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1273 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1274 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1275 } else {
1276 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1277 info_ptr->max_value = ALL_64_BITS;
1278
1279 // gettimeofday is a real time clock so it skips
1280 info_ptr->may_skip_backward = true;
1281 info_ptr->may_skip_forward = true;
1282 }
1283
1284 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1285 }
1286
1287 // Return the real, user, and system times in seconds from an
1288 // arbitrary fixed point in the past.
1289 bool os::getTimesSecs(double* process_real_time,
1290 double* process_user_time,
1291 double* process_system_time) {
1292 struct tms ticks;
1293 clock_t real_ticks = times(&ticks);
1294
1295 if (real_ticks == (clock_t) (-1)) {
1296 return false;
1297 } else {
1298 double ticks_per_second = (double) clock_tics_per_sec;
1299 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1300 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1301 *process_real_time = ((double) real_ticks) / ticks_per_second;
1302
1303 return true;
1304 }
1305 }
1306
1307
1308 char * os::local_time_string(char *buf, size_t buflen) {
1309 struct tm t;
1310 time_t long_time;
1311 time(&long_time);
1312 localtime_r(&long_time, &t);
1313 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1314 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1315 t.tm_hour, t.tm_min, t.tm_sec);
1316 return buf;
1317 }
1318
1319 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1320 return localtime_r(clock, res);
1321 }
1322
1323 ////////////////////////////////////////////////////////////////////////////////
1324 // runtime exit support
1325
1326 // Note: os::shutdown() might be called very early during initialization, or
1327 // called from signal handler. Before adding something to os::shutdown(), make
1328 // sure it is async-safe and can handle partially initialized VM.
1329 void os::shutdown() {
1330
1331 // allow PerfMemory to attempt cleanup of any persistent resources
1332 perfMemory_exit();
1333
1334 // needs to remove object in file system
1335 AttachListener::abort();
1336
1337 // flush buffered output, finish log files
1338 ostream_abort();
1339
1340 // Check for abort hook
1341 abort_hook_t abort_hook = Arguments::abort_hook();
1342 if (abort_hook != NULL) {
1343 abort_hook();
1344 }
1345
1346 }
1347
1348 // Note: os::abort() might be called very early during initialization, or
1349 // called from signal handler. Before adding something to os::abort(), make
1350 // sure it is async-safe and can handle partially initialized VM.
1351 void os::abort(bool dump_core, void* siginfo, const void* context) {
1352 os::shutdown();
1353 if (dump_core) {
1354 #ifndef PRODUCT
1355 fdStream out(defaultStream::output_fd());
1356 out.print_raw("Current thread is ");
1357 char buf[16];
1358 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1359 out.print_raw_cr(buf);
1360 out.print_raw_cr("Dumping core ...");
1361 #endif
1362 ::abort(); // dump core
1363 }
1364
1365 ::exit(1);
1366 }
1367
1368 // Die immediately, no exit hook, no abort hook, no cleanup.
1369 void os::die() {
1370 ::abort();
1371 }
1372
1373
1374 // This method is a copy of JDK's sysGetLastErrorString
1375 // from src/solaris/hpi/src/system_md.c
1376
1377 size_t os::lasterror(char *buf, size_t len) {
1378 if (errno == 0) return 0;
1379
1380 const char *s = os::strerror(errno);
1381 size_t n = ::strlen(s);
1382 if (n >= len) {
1383 n = len - 1;
1384 }
1385 ::strncpy(buf, s, n);
1386 buf[n] = '\0';
1387 return n;
1388 }
1389
1390 // thread_id is kernel thread id (similar to Solaris LWP id)
1391 intx os::current_thread_id() { return os::Linux::gettid(); }
1392 int os::current_process_id() {
1393 return ::getpid();
1394 }
1395
1396 // DLL functions
1397
1398 const char* os::dll_file_extension() { return ".so"; }
1399
1400 // This must be hard coded because it's the system's temporary
1401 // directory not the java application's temp directory, ala java.io.tmpdir.
1402 const char* os::get_temp_directory() { return "/tmp"; }
1403
1404 static bool file_exists(const char* filename) {
1405 struct stat statbuf;
1406 if (filename == NULL || strlen(filename) == 0) {
1407 return false;
1408 }
1409 return os::stat(filename, &statbuf) == 0;
1410 }
1411
1412 bool os::dll_build_name(char* buffer, size_t buflen,
1413 const char* pname, const char* fname) {
1414 bool retval = false;
1415 // Copied from libhpi
1416 const size_t pnamelen = pname ? strlen(pname) : 0;
1417
1418 // Return error on buffer overflow.
1419 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1420 return retval;
1421 }
1422
1423 if (pnamelen == 0) {
1424 snprintf(buffer, buflen, "lib%s.so", fname);
1425 retval = true;
1426 } else if (strchr(pname, *os::path_separator()) != NULL) {
1427 int n;
1428 char** pelements = split_path(pname, &n);
1429 if (pelements == NULL) {
1430 return false;
1431 }
1432 for (int i = 0; i < n; i++) {
1433 // Really shouldn't be NULL, but check can't hurt
1434 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1435 continue; // skip the empty path values
1436 }
1437 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1438 if (file_exists(buffer)) {
1439 retval = true;
1440 break;
1441 }
1442 }
1443 // release the storage
1444 for (int i = 0; i < n; i++) {
1445 if (pelements[i] != NULL) {
1446 FREE_C_HEAP_ARRAY(char, pelements[i]);
1447 }
1448 }
1449 if (pelements != NULL) {
1450 FREE_C_HEAP_ARRAY(char*, pelements);
1451 }
1452 } else {
1453 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1454 retval = true;
1455 }
1456 return retval;
1457 }
1458
1459 // check if addr is inside libjvm.so
1460 bool os::address_is_in_vm(address addr) {
1461 static address libjvm_base_addr;
1462 Dl_info dlinfo;
1463
1464 if (libjvm_base_addr == NULL) {
1465 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1466 libjvm_base_addr = (address)dlinfo.dli_fbase;
1467 }
1468 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1469 }
1470
1471 if (dladdr((void *)addr, &dlinfo) != 0) {
1472 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1473 }
1474
1475 return false;
1476 }
1477
1478 bool os::dll_address_to_function_name(address addr, char *buf,
1479 int buflen, int *offset,
1480 bool demangle) {
1481 // buf is not optional, but offset is optional
1482 assert(buf != NULL, "sanity check");
1483
1484 Dl_info dlinfo;
1485
1486 if (dladdr((void*)addr, &dlinfo) != 0) {
1487 // see if we have a matching symbol
1488 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1489 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1490 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1491 }
1492 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1493 return true;
1494 }
1495 // no matching symbol so try for just file info
1496 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1497 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1498 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1499 return true;
1500 }
1501 }
1502 }
1503
1504 buf[0] = '\0';
1505 if (offset != NULL) *offset = -1;
1506 return false;
1507 }
1508
1509 struct _address_to_library_name {
1510 address addr; // input : memory address
1511 size_t buflen; // size of fname
1512 char* fname; // output: library name
1513 address base; // library base addr
1514 };
1515
1516 static int address_to_library_name_callback(struct dl_phdr_info *info,
1517 size_t size, void *data) {
1518 int i;
1519 bool found = false;
1520 address libbase = NULL;
1521 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1522
1523 // iterate through all loadable segments
1524 for (i = 0; i < info->dlpi_phnum; i++) {
1525 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1526 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1527 // base address of a library is the lowest address of its loaded
1528 // segments.
1529 if (libbase == NULL || libbase > segbase) {
1530 libbase = segbase;
1531 }
1532 // see if 'addr' is within current segment
1533 if (segbase <= d->addr &&
1534 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1535 found = true;
1536 }
1537 }
1538 }
1539
1540 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1541 // so dll_address_to_library_name() can fall through to use dladdr() which
1542 // can figure out executable name from argv[0].
1543 if (found && info->dlpi_name && info->dlpi_name[0]) {
1544 d->base = libbase;
1545 if (d->fname) {
1546 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1547 }
1548 return 1;
1549 }
1550 return 0;
1551 }
1552
1553 bool os::dll_address_to_library_name(address addr, char* buf,
1554 int buflen, int* offset) {
1555 // buf is not optional, but offset is optional
1556 assert(buf != NULL, "sanity check");
1557
1558 Dl_info dlinfo;
1559 struct _address_to_library_name data;
1560
1561 // There is a bug in old glibc dladdr() implementation that it could resolve
1562 // to wrong library name if the .so file has a base address != NULL. Here
1563 // we iterate through the program headers of all loaded libraries to find
1564 // out which library 'addr' really belongs to. This workaround can be
1565 // removed once the minimum requirement for glibc is moved to 2.3.x.
1566 data.addr = addr;
1567 data.fname = buf;
1568 data.buflen = buflen;
1569 data.base = NULL;
1570 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1571
1572 if (rslt) {
1573 // buf already contains library name
1574 if (offset) *offset = addr - data.base;
1575 return true;
1576 }
1577 if (dladdr((void*)addr, &dlinfo) != 0) {
1578 if (dlinfo.dli_fname != NULL) {
1579 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1580 }
1581 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1582 *offset = addr - (address)dlinfo.dli_fbase;
1583 }
1584 return true;
1585 }
1586
1587 buf[0] = '\0';
1588 if (offset) *offset = -1;
1589 return false;
1590 }
1591
1592 // Loads .dll/.so and
1593 // in case of error it checks if .dll/.so was built for the
1594 // same architecture as Hotspot is running on
1595
1596
1597 // Remember the stack's state. The Linux dynamic linker will change
1598 // the stack to 'executable' at most once, so we must safepoint only once.
1599 bool os::Linux::_stack_is_executable = false;
1600
1601 // VM operation that loads a library. This is necessary if stack protection
1602 // of the Java stacks can be lost during loading the library. If we
1603 // do not stop the Java threads, they can stack overflow before the stacks
1604 // are protected again.
1605 class VM_LinuxDllLoad: public VM_Operation {
1606 private:
1607 const char *_filename;
1608 char *_ebuf;
1609 int _ebuflen;
1610 void *_lib;
1611 public:
1612 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1613 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1614 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1615 void doit() {
1616 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1617 os::Linux::_stack_is_executable = true;
1618 }
1619 void* loaded_library() { return _lib; }
1620 };
1621
1622 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1623 void * result = NULL;
1624 bool load_attempted = false;
1625
1626 // Check whether the library to load might change execution rights
1627 // of the stack. If they are changed, the protection of the stack
1628 // guard pages will be lost. We need a safepoint to fix this.
1629 //
1630 // See Linux man page execstack(8) for more info.
1631 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1632 ElfFile ef(filename);
1633 if (!ef.specifies_noexecstack()) {
1634 if (!is_init_completed()) {
1635 os::Linux::_stack_is_executable = true;
1636 // This is OK - No Java threads have been created yet, and hence no
1637 // stack guard pages to fix.
1638 //
1639 // This should happen only when you are building JDK7 using a very
1640 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1641 //
1642 // Dynamic loader will make all stacks executable after
1643 // this function returns, and will not do that again.
1644 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1645 } else {
1646 warning("You have loaded library %s which might have disabled stack guard. "
1647 "The VM will try to fix the stack guard now.\n"
1648 "It's highly recommended that you fix the library with "
1649 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1650 filename);
1651
1652 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1653 JavaThread *jt = JavaThread::current();
1654 if (jt->thread_state() != _thread_in_native) {
1655 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1656 // that requires ExecStack. Cannot enter safe point. Let's give up.
1657 warning("Unable to fix stack guard. Giving up.");
1658 } else {
1659 if (!LoadExecStackDllInVMThread) {
1660 // This is for the case where the DLL has an static
1661 // constructor function that executes JNI code. We cannot
1662 // load such DLLs in the VMThread.
1663 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1664 }
1665
1666 ThreadInVMfromNative tiv(jt);
1667 debug_only(VMNativeEntryWrapper vew;)
1668
1669 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1670 VMThread::execute(&op);
1671 if (LoadExecStackDllInVMThread) {
1672 result = op.loaded_library();
1673 }
1674 load_attempted = true;
1675 }
1676 }
1677 }
1678 }
1679
1680 if (!load_attempted) {
1681 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1682 }
1683
1684 if (result != NULL) {
1685 // Successful loading
1686 return result;
1687 }
1688
1689 Elf32_Ehdr elf_head;
1690 int diag_msg_max_length=ebuflen-strlen(ebuf);
1691 char* diag_msg_buf=ebuf+strlen(ebuf);
1692
1693 if (diag_msg_max_length==0) {
1694 // No more space in ebuf for additional diagnostics message
1695 return NULL;
1696 }
1697
1698
1699 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1700
1701 if (file_descriptor < 0) {
1702 // Can't open library, report dlerror() message
1703 return NULL;
1704 }
1705
1706 bool failed_to_read_elf_head=
1707 (sizeof(elf_head)!=
1708 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1709
1710 ::close(file_descriptor);
1711 if (failed_to_read_elf_head) {
1712 // file i/o error - report dlerror() msg
1713 return NULL;
1714 }
1715
1716 typedef struct {
1717 Elf32_Half code; // Actual value as defined in elf.h
1718 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1719 unsigned char elf_class; // 32 or 64 bit
1720 unsigned char endianess; // MSB or LSB
1721 char* name; // String representation
1722 } arch_t;
1723
1724 #ifndef EM_486
1725 #define EM_486 6 /* Intel 80486 */
1726 #endif
1727 #ifndef EM_AARCH64
1728 #define EM_AARCH64 183 /* ARM AARCH64 */
1729 #endif
1730
1731 static const arch_t arch_array[]={
1732 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1733 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1734 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1735 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1736 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1737 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1738 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1739 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1740 #if defined(VM_LITTLE_ENDIAN)
1741 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1742 #else
1743 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1744 #endif
1745 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1746 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1747 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1748 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1749 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1750 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1751 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1752 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1753 };
1754
1755 #if (defined IA32)
1756 static Elf32_Half running_arch_code=EM_386;
1757 #elif (defined AMD64)
1758 static Elf32_Half running_arch_code=EM_X86_64;
1759 #elif (defined IA64)
1760 static Elf32_Half running_arch_code=EM_IA_64;
1761 #elif (defined __sparc) && (defined _LP64)
1762 static Elf32_Half running_arch_code=EM_SPARCV9;
1763 #elif (defined __sparc) && (!defined _LP64)
1764 static Elf32_Half running_arch_code=EM_SPARC;
1765 #elif (defined __powerpc64__)
1766 static Elf32_Half running_arch_code=EM_PPC64;
1767 #elif (defined __powerpc__)
1768 static Elf32_Half running_arch_code=EM_PPC;
1769 #elif (defined AARCH64)
1770 static Elf32_Half running_arch_code=EM_AARCH64;
1771 #elif (defined ARM)
1772 static Elf32_Half running_arch_code=EM_ARM;
1773 #elif (defined S390)
1774 static Elf32_Half running_arch_code=EM_S390;
1775 #elif (defined ALPHA)
1776 static Elf32_Half running_arch_code=EM_ALPHA;
1777 #elif (defined MIPSEL)
1778 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1779 #elif (defined PARISC)
1780 static Elf32_Half running_arch_code=EM_PARISC;
1781 #elif (defined MIPS)
1782 static Elf32_Half running_arch_code=EM_MIPS;
1783 #elif (defined M68K)
1784 static Elf32_Half running_arch_code=EM_68K;
1785 #else
1786 #error Method os::dll_load requires that one of following is defined:\
1787 AARCH64, ALPHA, ARM, AMD64, IA32, IA64, M68K, MIPS, MIPSEL, PARISC, __powerpc__, __powerpc64__, S390, __sparc
1788 #endif
1789
1790 // Identify compatability class for VM's architecture and library's architecture
1791 // Obtain string descriptions for architectures
1792
1793 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1794 int running_arch_index=-1;
1795
1796 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1797 if (running_arch_code == arch_array[i].code) {
1798 running_arch_index = i;
1799 }
1800 if (lib_arch.code == arch_array[i].code) {
1801 lib_arch.compat_class = arch_array[i].compat_class;
1802 lib_arch.name = arch_array[i].name;
1803 }
1804 }
1805
1806 assert(running_arch_index != -1,
1807 "Didn't find running architecture code (running_arch_code) in arch_array");
1808 if (running_arch_index == -1) {
1809 // Even though running architecture detection failed
1810 // we may still continue with reporting dlerror() message
1811 return NULL;
1812 }
1813
1814 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1815 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1816 return NULL;
1817 }
1818
1819 #ifndef S390
1820 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1821 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1822 return NULL;
1823 }
1824 #endif // !S390
1825
1826 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1827 if (lib_arch.name!=NULL) {
1828 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1829 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1830 lib_arch.name, arch_array[running_arch_index].name);
1831 } else {
1832 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1833 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1834 lib_arch.code,
1835 arch_array[running_arch_index].name);
1836 }
1837 }
1838
1839 return NULL;
1840 }
1841
1842 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1843 int ebuflen) {
1844 void * result = ::dlopen(filename, RTLD_LAZY);
1845 if (result == NULL) {
1846 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1847 ebuf[ebuflen-1] = '\0';
1848 }
1849 return result;
1850 }
1851
1852 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1853 int ebuflen) {
1854 void * result = NULL;
1855 if (LoadExecStackDllInVMThread) {
1856 result = dlopen_helper(filename, ebuf, ebuflen);
1857 }
1858
1859 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1860 // library that requires an executable stack, or which does not have this
1861 // stack attribute set, dlopen changes the stack attribute to executable. The
1862 // read protection of the guard pages gets lost.
1863 //
1864 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1865 // may have been queued at the same time.
1866
1867 if (!_stack_is_executable) {
1868 JavaThread *jt = Threads::first();
1869
1870 while (jt) {
1871 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1872 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1873 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1874 warning("Attempt to reguard stack yellow zone failed.");
1875 }
1876 }
1877 jt = jt->next();
1878 }
1879 }
1880
1881 return result;
1882 }
1883
1884 void* os::dll_lookup(void* handle, const char* name) {
1885 void* res = dlsym(handle, name);
1886 return res;
1887 }
1888
1889 void* os::get_default_process_handle() {
1890 return (void*)::dlopen(NULL, RTLD_LAZY);
1891 }
1892
1893 static bool _print_ascii_file(const char* filename, outputStream* st) {
1894 int fd = ::open(filename, O_RDONLY);
1895 if (fd == -1) {
1896 return false;
1897 }
1898
1899 char buf[33];
1900 int bytes;
1901 buf[32] = '\0';
1902 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1903 st->print_raw(buf, bytes);
1904 }
1905
1906 ::close(fd);
1907
1908 return true;
1909 }
1910
1911 void os::print_dll_info(outputStream *st) {
1912 st->print_cr("Dynamic libraries:");
1913
1914 char fname[32];
1915 pid_t pid = os::Linux::gettid();
1916
1917 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1918
1919 if (!_print_ascii_file(fname, st)) {
1920 st->print("Can not get library information for pid = %d\n", pid);
1921 }
1922 }
1923
1924 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1925 FILE *procmapsFile = NULL;
1926
1927 // Open the procfs maps file for the current process
1928 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1929 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1930 char line[PATH_MAX + 100];
1931
1932 // Read line by line from 'file'
1933 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1934 u8 base, top, offset, inode;
1935 char permissions[5];
1936 char device[6];
1937 char name[PATH_MAX + 1];
1938
1939 // Parse fields from line
1940 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1941 &base, &top, permissions, &offset, device, &inode, name);
1942
1943 // Filter by device id '00:00' so that we only get file system mapped files.
1944 if (strcmp(device, "00:00") != 0) {
1945
1946 // Call callback with the fields of interest
1947 if(callback(name, (address)base, (address)top, param)) {
1948 // Oops abort, callback aborted
1949 fclose(procmapsFile);
1950 return 1;
1951 }
1952 }
1953 }
1954 fclose(procmapsFile);
1955 }
1956 return 0;
1957 }
1958
1959 void os::print_os_info_brief(outputStream* st) {
1960 os::Linux::print_distro_info(st);
1961
1962 os::Posix::print_uname_info(st);
1963
1964 os::Linux::print_libversion_info(st);
1965
1966 }
1967
1968 void os::print_os_info(outputStream* st) {
1969 st->print("OS:");
1970
1971 os::Linux::print_distro_info(st);
1972
1973 os::Posix::print_uname_info(st);
1974
1975 // Print warning if unsafe chroot environment detected
1976 if (unsafe_chroot_detected) {
1977 st->print("WARNING!! ");
1978 st->print_cr("%s", unstable_chroot_error);
1979 }
1980
1981 os::Linux::print_libversion_info(st);
1982
1983 os::Posix::print_rlimit_info(st);
1984
1985 os::Posix::print_load_average(st);
1986
1987 os::Linux::print_full_memory_info(st);
1988 }
1989
1990 // Try to identify popular distros.
1991 // Most Linux distributions have a /etc/XXX-release file, which contains
1992 // the OS version string. Newer Linux distributions have a /etc/lsb-release
1993 // file that also contains the OS version string. Some have more than one
1994 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
1995 // /etc/redhat-release.), so the order is important.
1996 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
1997 // their own specific XXX-release file as well as a redhat-release file.
1998 // Because of this the XXX-release file needs to be searched for before the
1999 // redhat-release file.
2000 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2001 // search for redhat-release / SuSE-release needs to be before lsb-release.
2002 // Since the lsb-release file is the new standard it needs to be searched
2003 // before the older style release files.
2004 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2005 // next to last resort. The os-release file is a new standard that contains
2006 // distribution information and the system-release file seems to be an old
2007 // standard that has been replaced by the lsb-release and os-release files.
2008 // Searching for the debian_version file is the last resort. It contains
2009 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2010 // "Debian " is printed before the contents of the debian_version file.
2011
2012 const char* distro_files[] = {
2013 "/etc/oracle-release",
2014 "/etc/mandriva-release",
2015 "/etc/mandrake-release",
2016 "/etc/sun-release",
2017 "/etc/redhat-release",
2018 "/etc/SuSE-release",
2019 "/etc/lsb-release",
2020 "/etc/turbolinux-release",
2021 "/etc/gentoo-release",
2022 "/etc/ltib-release",
2023 "/etc/angstrom-version",
2024 "/etc/system-release",
2025 "/etc/os-release",
2026 NULL };
2027
2028 void os::Linux::print_distro_info(outputStream* st) {
2029 for (int i = 0;; i++) {
2030 const char* file = distro_files[i];
2031 if (file == NULL) {
2032 break; // done
2033 }
2034 // If file prints, we found it.
2035 if (_print_ascii_file(file, st)) {
2036 return;
2037 }
2038 }
2039
2040 if (file_exists("/etc/debian_version")) {
2041 st->print("Debian ");
2042 _print_ascii_file("/etc/debian_version", st);
2043 } else {
2044 st->print("Linux");
2045 }
2046 st->cr();
2047 }
2048
2049 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2050 char buf[256];
2051 while (fgets(buf, sizeof(buf), fp)) {
2052 // Edit out extra stuff in expected format
2053 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2054 char* ptr = strstr(buf, "\""); // the name is in quotes
2055 if (ptr != NULL) {
2056 ptr++; // go beyond first quote
2057 char* nl = strchr(ptr, '\"');
2058 if (nl != NULL) *nl = '\0';
2059 strncpy(distro, ptr, length);
2060 } else {
2061 ptr = strstr(buf, "=");
2062 ptr++; // go beyond equals then
2063 char* nl = strchr(ptr, '\n');
2064 if (nl != NULL) *nl = '\0';
2065 strncpy(distro, ptr, length);
2066 }
2067 return;
2068 } else if (get_first_line) {
2069 char* nl = strchr(buf, '\n');
2070 if (nl != NULL) *nl = '\0';
2071 strncpy(distro, buf, length);
2072 return;
2073 }
2074 }
2075 // print last line and close
2076 char* nl = strchr(buf, '\n');
2077 if (nl != NULL) *nl = '\0';
2078 strncpy(distro, buf, length);
2079 }
2080
2081 static void parse_os_info(char* distro, size_t length, const char* file) {
2082 FILE* fp = fopen(file, "r");
2083 if (fp != NULL) {
2084 // if suse format, print out first line
2085 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2086 parse_os_info_helper(fp, distro, length, get_first_line);
2087 fclose(fp);
2088 }
2089 }
2090
2091 void os::get_summary_os_info(char* buf, size_t buflen) {
2092 for (int i = 0;; i++) {
2093 const char* file = distro_files[i];
2094 if (file == NULL) {
2095 break; // ran out of distro_files
2096 }
2097 if (file_exists(file)) {
2098 parse_os_info(buf, buflen, file);
2099 return;
2100 }
2101 }
2102 // special case for debian
2103 if (file_exists("/etc/debian_version")) {
2104 strncpy(buf, "Debian ", buflen);
2105 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2106 } else {
2107 strncpy(buf, "Linux", buflen);
2108 }
2109 }
2110
2111 void os::Linux::print_libversion_info(outputStream* st) {
2112 // libc, pthread
2113 st->print("libc:");
2114 st->print("%s ", os::Linux::glibc_version());
2115 st->print("%s ", os::Linux::libpthread_version());
2116 st->cr();
2117 }
2118
2119 void os::Linux::print_full_memory_info(outputStream* st) {
2120 st->print("\n/proc/meminfo:\n");
2121 _print_ascii_file("/proc/meminfo", st);
2122 st->cr();
2123 }
2124
2125 void os::print_memory_info(outputStream* st) {
2126
2127 st->print("Memory:");
2128 st->print(" %dk page", os::vm_page_size()>>10);
2129
2130 // values in struct sysinfo are "unsigned long"
2131 struct sysinfo si;
2132 sysinfo(&si);
2133
2134 st->print(", physical " UINT64_FORMAT "k",
2135 os::physical_memory() >> 10);
2136 st->print("(" UINT64_FORMAT "k free)",
2137 os::available_memory() >> 10);
2138 st->print(", swap " UINT64_FORMAT "k",
2139 ((jlong)si.totalswap * si.mem_unit) >> 10);
2140 st->print("(" UINT64_FORMAT "k free)",
2141 ((jlong)si.freeswap * si.mem_unit) >> 10);
2142 st->cr();
2143 }
2144
2145 // Print the first "model name" line and the first "flags" line
2146 // that we find and nothing more. We assume "model name" comes
2147 // before "flags" so if we find a second "model name", then the
2148 // "flags" field is considered missing.
2149 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2150 #if defined(IA32) || defined(AMD64)
2151 // Other platforms have less repetitive cpuinfo files
2152 FILE *fp = fopen("/proc/cpuinfo", "r");
2153 if (fp) {
2154 while (!feof(fp)) {
2155 if (fgets(buf, buflen, fp)) {
2156 // Assume model name comes before flags
2157 bool model_name_printed = false;
2158 if (strstr(buf, "model name") != NULL) {
2159 if (!model_name_printed) {
2160 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2161 st->print_raw(buf);
2162 model_name_printed = true;
2163 } else {
2164 // model name printed but not flags? Odd, just return
2165 fclose(fp);
2166 return true;
2167 }
2168 }
2169 // print the flags line too
2170 if (strstr(buf, "flags") != NULL) {
2171 st->print_raw(buf);
2172 fclose(fp);
2173 return true;
2174 }
2175 }
2176 }
2177 fclose(fp);
2178 }
2179 #endif // x86 platforms
2180 return false;
2181 }
2182
2183 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2184 // Only print the model name if the platform provides this as a summary
2185 if (!print_model_name_and_flags(st, buf, buflen)) {
2186 st->print("\n/proc/cpuinfo:\n");
2187 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2188 st->print_cr(" <Not Available>");
2189 }
2190 }
2191 }
2192
2193 #if defined(AMD64) || defined(IA32) || defined(X32)
2194 const char* search_string = "model name";
2195 #elif defined(PPC64)
2196 const char* search_string = "cpu";
2197 #elif defined(S390)
2198 const char* search_string = "processor";
2199 #elif defined(SPARC)
2200 const char* search_string = "cpu";
2201 #else
2202 const char* search_string = "Processor";
2203 #endif
2204
2205 // Parses the cpuinfo file for string representing the model name.
2206 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2207 FILE* fp = fopen("/proc/cpuinfo", "r");
2208 if (fp != NULL) {
2209 while (!feof(fp)) {
2210 char buf[256];
2211 if (fgets(buf, sizeof(buf), fp)) {
2212 char* start = strstr(buf, search_string);
2213 if (start != NULL) {
2214 char *ptr = start + strlen(search_string);
2215 char *end = buf + strlen(buf);
2216 while (ptr != end) {
2217 // skip whitespace and colon for the rest of the name.
2218 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2219 break;
2220 }
2221 ptr++;
2222 }
2223 if (ptr != end) {
2224 // reasonable string, get rid of newline and keep the rest
2225 char* nl = strchr(buf, '\n');
2226 if (nl != NULL) *nl = '\0';
2227 strncpy(cpuinfo, ptr, length);
2228 fclose(fp);
2229 return;
2230 }
2231 }
2232 }
2233 }
2234 fclose(fp);
2235 }
2236 // cpuinfo not found or parsing failed, just print generic string. The entire
2237 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2238 #if defined(AARCH64)
2239 strncpy(cpuinfo, "AArch64", length);
2240 #elif defined(AMD64)
2241 strncpy(cpuinfo, "x86_64", length);
2242 #elif defined(ARM) // Order wrt. AARCH64 is relevant!
2243 strncpy(cpuinfo, "ARM", length);
2244 #elif defined(IA32)
2245 strncpy(cpuinfo, "x86_32", length);
2246 #elif defined(IA64)
2247 strncpy(cpuinfo, "IA64", length);
2248 #elif defined(PPC)
2249 strncpy(cpuinfo, "PPC64", length);
2250 #elif defined(S390)
2251 strncpy(cpuinfo, "S390", length);
2252 #elif defined(SPARC)
2253 strncpy(cpuinfo, "sparcv9", length);
2254 #elif defined(ZERO_LIBARCH)
2255 strncpy(cpuinfo, ZERO_LIBARCH, length);
2256 #else
2257 strncpy(cpuinfo, "unknown", length);
2258 #endif
2259 }
2260
2261 static void print_signal_handler(outputStream* st, int sig,
2262 char* buf, size_t buflen);
2263
2264 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2265 st->print_cr("Signal Handlers:");
2266 print_signal_handler(st, SIGSEGV, buf, buflen);
2267 print_signal_handler(st, SIGBUS , buf, buflen);
2268 print_signal_handler(st, SIGFPE , buf, buflen);
2269 print_signal_handler(st, SIGPIPE, buf, buflen);
2270 print_signal_handler(st, SIGXFSZ, buf, buflen);
2271 print_signal_handler(st, SIGILL , buf, buflen);
2272 print_signal_handler(st, SR_signum, buf, buflen);
2273 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2274 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2275 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2276 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2277 #if defined(PPC64)
2278 print_signal_handler(st, SIGTRAP, buf, buflen);
2279 #endif
2280 }
2281
2282 static char saved_jvm_path[MAXPATHLEN] = {0};
2283
2284 // Find the full path to the current module, libjvm.so
2285 void os::jvm_path(char *buf, jint buflen) {
2286 // Error checking.
2287 if (buflen < MAXPATHLEN) {
2288 assert(false, "must use a large-enough buffer");
2289 buf[0] = '\0';
2290 return;
2291 }
2292 // Lazy resolve the path to current module.
2293 if (saved_jvm_path[0] != 0) {
2294 strcpy(buf, saved_jvm_path);
2295 return;
2296 }
2297
2298 char dli_fname[MAXPATHLEN];
2299 bool ret = dll_address_to_library_name(
2300 CAST_FROM_FN_PTR(address, os::jvm_path),
2301 dli_fname, sizeof(dli_fname), NULL);
2302 assert(ret, "cannot locate libjvm");
2303 char *rp = NULL;
2304 if (ret && dli_fname[0] != '\0') {
2305 rp = realpath(dli_fname, buf);
2306 }
2307 if (rp == NULL) {
2308 return;
2309 }
2310
2311 if (Arguments::sun_java_launcher_is_altjvm()) {
2312 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2313 // value for buf is "<JAVA_HOME>/jre/lib/<vmtype>/libjvm.so".
2314 // If "/jre/lib/" appears at the right place in the string, then
2315 // assume we are installed in a JDK and we're done. Otherwise, check
2316 // for a JAVA_HOME environment variable and fix up the path so it
2317 // looks like libjvm.so is installed there (append a fake suffix
2318 // hotspot/libjvm.so).
2319 const char *p = buf + strlen(buf) - 1;
2320 for (int count = 0; p > buf && count < 5; ++count) {
2321 for (--p; p > buf && *p != '/'; --p)
2322 /* empty */ ;
2323 }
2324
2325 if (strncmp(p, "/jre/lib/", 9) != 0) {
2326 // Look for JAVA_HOME in the environment.
2327 char* java_home_var = ::getenv("JAVA_HOME");
2328 if (java_home_var != NULL && java_home_var[0] != 0) {
2329 char* jrelib_p;
2330 int len;
2331
2332 // Check the current module name "libjvm.so".
2333 p = strrchr(buf, '/');
2334 if (p == NULL) {
2335 return;
2336 }
2337 assert(strstr(p, "/libjvm") == p, "invalid library name");
2338
2339 rp = realpath(java_home_var, buf);
2340 if (rp == NULL) {
2341 return;
2342 }
2343
2344 // determine if this is a legacy image or modules image
2345 // modules image doesn't have "jre" subdirectory
2346 len = strlen(buf);
2347 assert(len < buflen, "Ran out of buffer room");
2348 jrelib_p = buf + len;
2349 snprintf(jrelib_p, buflen-len, "/jre/lib");
2350 if (0 != access(buf, F_OK)) {
2351 snprintf(jrelib_p, buflen-len, "/lib");
2352 }
2353
2354 if (0 == access(buf, F_OK)) {
2355 // Use current module name "libjvm.so"
2356 len = strlen(buf);
2357 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2358 } else {
2359 // Go back to path of .so
2360 rp = realpath(dli_fname, buf);
2361 if (rp == NULL) {
2362 return;
2363 }
2364 }
2365 }
2366 }
2367 }
2368
2369 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2370 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2371 }
2372
2373 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2374 // no prefix required, not even "_"
2375 }
2376
2377 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2378 // no suffix required
2379 }
2380
2381 ////////////////////////////////////////////////////////////////////////////////
2382 // sun.misc.Signal support
2383
2384 static volatile jint sigint_count = 0;
2385
2386 static void UserHandler(int sig, void *siginfo, void *context) {
2387 // 4511530 - sem_post is serialized and handled by the manager thread. When
2388 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2389 // don't want to flood the manager thread with sem_post requests.
2390 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2391 return;
2392 }
2393
2394 // Ctrl-C is pressed during error reporting, likely because the error
2395 // handler fails to abort. Let VM die immediately.
2396 if (sig == SIGINT && is_error_reported()) {
2397 os::die();
2398 }
2399
2400 os::signal_notify(sig);
2401 }
2402
2403 void* os::user_handler() {
2404 return CAST_FROM_FN_PTR(void*, UserHandler);
2405 }
2406
2407 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2408 struct timespec ts;
2409 // Semaphore's are always associated with CLOCK_REALTIME
2410 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2411 // see unpackTime for discussion on overflow checking
2412 if (sec >= MAX_SECS) {
2413 ts.tv_sec += MAX_SECS;
2414 ts.tv_nsec = 0;
2415 } else {
2416 ts.tv_sec += sec;
2417 ts.tv_nsec += nsec;
2418 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2419 ts.tv_nsec -= NANOSECS_PER_SEC;
2420 ++ts.tv_sec; // note: this must be <= max_secs
2421 }
2422 }
2423
2424 return ts;
2425 }
2426
2427 extern "C" {
2428 typedef void (*sa_handler_t)(int);
2429 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2430 }
2431
2432 void* os::signal(int signal_number, void* handler) {
2433 struct sigaction sigAct, oldSigAct;
2434
2435 sigfillset(&(sigAct.sa_mask));
2436 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2437 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2438
2439 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2440 // -1 means registration failed
2441 return (void *)-1;
2442 }
2443
2444 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2445 }
2446
2447 void os::signal_raise(int signal_number) {
2448 ::raise(signal_number);
2449 }
2450
2451 // The following code is moved from os.cpp for making this
2452 // code platform specific, which it is by its very nature.
2453
2454 // Will be modified when max signal is changed to be dynamic
2455 int os::sigexitnum_pd() {
2456 return NSIG;
2457 }
2458
2459 // a counter for each possible signal value
2460 static volatile jint pending_signals[NSIG+1] = { 0 };
2461
2462 // Linux(POSIX) specific hand shaking semaphore.
2463 static sem_t sig_sem;
2464 static PosixSemaphore sr_semaphore;
2465
2466 void os::signal_init_pd() {
2467 // Initialize signal structures
2468 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2469
2470 // Initialize signal semaphore
2471 ::sem_init(&sig_sem, 0, 0);
2472 }
2473
2474 void os::signal_notify(int sig) {
2475 Atomic::inc(&pending_signals[sig]);
2476 ::sem_post(&sig_sem);
2477 }
2478
2479 static int check_pending_signals(bool wait) {
2480 Atomic::store(0, &sigint_count);
2481 for (;;) {
2482 for (int i = 0; i < NSIG + 1; i++) {
2483 jint n = pending_signals[i];
2484 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2485 return i;
2486 }
2487 }
2488 if (!wait) {
2489 return -1;
2490 }
2491 JavaThread *thread = JavaThread::current();
2492 ThreadBlockInVM tbivm(thread);
2493
2494 bool threadIsSuspended;
2495 do {
2496 thread->set_suspend_equivalent();
2497 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2498 ::sem_wait(&sig_sem);
2499
2500 // were we externally suspended while we were waiting?
2501 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2502 if (threadIsSuspended) {
2503 // The semaphore has been incremented, but while we were waiting
2504 // another thread suspended us. We don't want to continue running
2505 // while suspended because that would surprise the thread that
2506 // suspended us.
2507 ::sem_post(&sig_sem);
2508
2509 thread->java_suspend_self();
2510 }
2511 } while (threadIsSuspended);
2512 }
2513 }
2514
2515 int os::signal_lookup() {
2516 return check_pending_signals(false);
2517 }
2518
2519 int os::signal_wait() {
2520 return check_pending_signals(true);
2521 }
2522
2523 ////////////////////////////////////////////////////////////////////////////////
2524 // Virtual Memory
2525
2526 int os::vm_page_size() {
2527 // Seems redundant as all get out
2528 assert(os::Linux::page_size() != -1, "must call os::init");
2529 return os::Linux::page_size();
2530 }
2531
2532 // Solaris allocates memory by pages.
2533 int os::vm_allocation_granularity() {
2534 assert(os::Linux::page_size() != -1, "must call os::init");
2535 return os::Linux::page_size();
2536 }
2537
2538 // Rationale behind this function:
2539 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2540 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2541 // samples for JITted code. Here we create private executable mapping over the code cache
2542 // and then we can use standard (well, almost, as mapping can change) way to provide
2543 // info for the reporting script by storing timestamp and location of symbol
2544 void linux_wrap_code(char* base, size_t size) {
2545 static volatile jint cnt = 0;
2546
2547 if (!UseOprofile) {
2548 return;
2549 }
2550
2551 char buf[PATH_MAX+1];
2552 int num = Atomic::add(1, &cnt);
2553
2554 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2555 os::get_temp_directory(), os::current_process_id(), num);
2556 unlink(buf);
2557
2558 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2559
2560 if (fd != -1) {
2561 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2562 if (rv != (off_t)-1) {
2563 if (::write(fd, "", 1) == 1) {
2564 mmap(base, size,
2565 PROT_READ|PROT_WRITE|PROT_EXEC,
2566 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2567 }
2568 }
2569 ::close(fd);
2570 unlink(buf);
2571 }
2572 }
2573
2574 static bool recoverable_mmap_error(int err) {
2575 // See if the error is one we can let the caller handle. This
2576 // list of errno values comes from JBS-6843484. I can't find a
2577 // Linux man page that documents this specific set of errno
2578 // values so while this list currently matches Solaris, it may
2579 // change as we gain experience with this failure mode.
2580 switch (err) {
2581 case EBADF:
2582 case EINVAL:
2583 case ENOTSUP:
2584 // let the caller deal with these errors
2585 return true;
2586
2587 default:
2588 // Any remaining errors on this OS can cause our reserved mapping
2589 // to be lost. That can cause confusion where different data
2590 // structures think they have the same memory mapped. The worst
2591 // scenario is if both the VM and a library think they have the
2592 // same memory mapped.
2593 return false;
2594 }
2595 }
2596
2597 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2598 int err) {
2599 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2600 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2601 os::strerror(err), err);
2602 }
2603
2604 static void warn_fail_commit_memory(char* addr, size_t size,
2605 size_t alignment_hint, bool exec,
2606 int err) {
2607 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2608 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2609 alignment_hint, exec, os::strerror(err), err);
2610 }
2611
2612 // NOTE: Linux kernel does not really reserve the pages for us.
2613 // All it does is to check if there are enough free pages
2614 // left at the time of mmap(). This could be a potential
2615 // problem.
2616 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2617 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2618 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2619 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2620 if (res != (uintptr_t) MAP_FAILED) {
2621 if (UseNUMAInterleaving) {
2622 numa_make_global(addr, size);
2623 }
2624 return 0;
2625 }
2626
2627 int err = errno; // save errno from mmap() call above
2628
2629 if (!recoverable_mmap_error(err)) {
2630 warn_fail_commit_memory(addr, size, exec, err);
2631 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2632 }
2633
2634 return err;
2635 }
2636
2637 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2638 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2639 }
2640
2641 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2642 const char* mesg) {
2643 assert(mesg != NULL, "mesg must be specified");
2644 int err = os::Linux::commit_memory_impl(addr, size, exec);
2645 if (err != 0) {
2646 // the caller wants all commit errors to exit with the specified mesg:
2647 warn_fail_commit_memory(addr, size, exec, err);
2648 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2649 }
2650 }
2651
2652 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2653 #ifndef MAP_HUGETLB
2654 #define MAP_HUGETLB 0x40000
2655 #endif
2656
2657 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2658 #ifndef MADV_HUGEPAGE
2659 #define MADV_HUGEPAGE 14
2660 #endif
2661
2662 int os::Linux::commit_memory_impl(char* addr, size_t size,
2663 size_t alignment_hint, bool exec) {
2664 int err = os::Linux::commit_memory_impl(addr, size, exec);
2665 if (err == 0) {
2666 realign_memory(addr, size, alignment_hint);
2667 }
2668 return err;
2669 }
2670
2671 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2672 bool exec) {
2673 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2674 }
2675
2676 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2677 size_t alignment_hint, bool exec,
2678 const char* mesg) {
2679 assert(mesg != NULL, "mesg must be specified");
2680 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2681 if (err != 0) {
2682 // the caller wants all commit errors to exit with the specified mesg:
2683 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2684 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2685 }
2686 }
2687
2688 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2689 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2690 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2691 // be supported or the memory may already be backed by huge pages.
2692 ::madvise(addr, bytes, MADV_HUGEPAGE);
2693 }
2694 }
2695
2696 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2697 // This method works by doing an mmap over an existing mmaping and effectively discarding
2698 // the existing pages. However it won't work for SHM-based large pages that cannot be
2699 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2700 // small pages on top of the SHM segment. This method always works for small pages, so we
2701 // allow that in any case.
2702 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2703 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2704 }
2705 }
2706
2707 void os::numa_make_global(char *addr, size_t bytes) {
2708 Linux::numa_interleave_memory(addr, bytes);
2709 }
2710
2711 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2712 // bind policy to MPOL_PREFERRED for the current thread.
2713 #define USE_MPOL_PREFERRED 0
2714
2715 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2716 // To make NUMA and large pages more robust when both enabled, we need to ease
2717 // the requirements on where the memory should be allocated. MPOL_BIND is the
2718 // default policy and it will force memory to be allocated on the specified
2719 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2720 // the specified node, but will not force it. Using this policy will prevent
2721 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2722 // free large pages.
2723 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2724 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2725 }
2726
2727 bool os::numa_topology_changed() { return false; }
2728
2729 size_t os::numa_get_groups_num() {
2730 int max_node = Linux::numa_max_node();
2731 return max_node > 0 ? max_node + 1 : 1;
2732 }
2733
2734 int os::numa_get_group_id() {
2735 int cpu_id = Linux::sched_getcpu();
2736 if (cpu_id != -1) {
2737 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2738 if (lgrp_id != -1) {
2739 return lgrp_id;
2740 }
2741 }
2742 return 0;
2743 }
2744
2745 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2746 for (size_t i = 0; i < size; i++) {
2747 ids[i] = i;
2748 }
2749 return size;
2750 }
2751
2752 bool os::get_page_info(char *start, page_info* info) {
2753 return false;
2754 }
2755
2756 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2757 page_info* page_found) {
2758 return end;
2759 }
2760
2761
2762 int os::Linux::sched_getcpu_syscall(void) {
2763 unsigned int cpu = 0;
2764 int retval = -1;
2765
2766 #if defined(IA32)
2767 #ifndef SYS_getcpu
2768 #define SYS_getcpu 318
2769 #endif
2770 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2771 #elif defined(AMD64)
2772 // Unfortunately we have to bring all these macros here from vsyscall.h
2773 // to be able to compile on old linuxes.
2774 #define __NR_vgetcpu 2
2775 #define VSYSCALL_START (-10UL << 20)
2776 #define VSYSCALL_SIZE 1024
2777 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2778 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2779 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2780 retval = vgetcpu(&cpu, NULL, NULL);
2781 #endif
2782
2783 return (retval == -1) ? retval : cpu;
2784 }
2785
2786 // Something to do with the numa-aware allocator needs these symbols
2787 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2788 extern "C" JNIEXPORT void numa_error(char *where) { }
2789
2790
2791 // If we are running with libnuma version > 2, then we should
2792 // be trying to use symbols with versions 1.1
2793 // If we are running with earlier version, which did not have symbol versions,
2794 // we should use the base version.
2795 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2796 void *f = dlvsym(handle, name, "libnuma_1.1");
2797 if (f == NULL) {
2798 f = dlsym(handle, name);
2799 }
2800 return f;
2801 }
2802
2803 bool os::Linux::libnuma_init() {
2804 // sched_getcpu() should be in libc.
2805 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2806 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2807
2808 // If it's not, try a direct syscall.
2809 if (sched_getcpu() == -1) {
2810 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2811 (void*)&sched_getcpu_syscall));
2812 }
2813
2814 if (sched_getcpu() != -1) { // Does it work?
2815 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2816 if (handle != NULL) {
2817 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2818 libnuma_dlsym(handle, "numa_node_to_cpus")));
2819 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2820 libnuma_dlsym(handle, "numa_max_node")));
2821 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2822 libnuma_dlsym(handle, "numa_available")));
2823 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2824 libnuma_dlsym(handle, "numa_tonode_memory")));
2825 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2826 libnuma_dlsym(handle, "numa_interleave_memory")));
2827 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2828 libnuma_dlsym(handle, "numa_set_bind_policy")));
2829
2830
2831 if (numa_available() != -1) {
2832 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2833 // Create a cpu -> node mapping
2834 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2835 rebuild_cpu_to_node_map();
2836 return true;
2837 }
2838 }
2839 }
2840 return false;
2841 }
2842
2843 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
2844 // Creating guard page is very expensive. Java thread has HotSpot
2845 // guard pages, only enable glibc guard page for non-Java threads.
2846 // (Remember: compiler thread is a Java thread, too!)
2847 return ((thr_type == java_thread || thr_type == compiler_thread) ? 0 : page_size());
2848 }
2849
2850 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2851 // The table is later used in get_node_by_cpu().
2852 void os::Linux::rebuild_cpu_to_node_map() {
2853 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2854 // in libnuma (possible values are starting from 16,
2855 // and continuing up with every other power of 2, but less
2856 // than the maximum number of CPUs supported by kernel), and
2857 // is a subject to change (in libnuma version 2 the requirements
2858 // are more reasonable) we'll just hardcode the number they use
2859 // in the library.
2860 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2861
2862 size_t cpu_num = processor_count();
2863 size_t cpu_map_size = NCPUS / BitsPerCLong;
2864 size_t cpu_map_valid_size =
2865 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2866
2867 cpu_to_node()->clear();
2868 cpu_to_node()->at_grow(cpu_num - 1);
2869 size_t node_num = numa_get_groups_num();
2870
2871 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2872 for (size_t i = 0; i < node_num; i++) {
2873 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2874 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2875 if (cpu_map[j] != 0) {
2876 for (size_t k = 0; k < BitsPerCLong; k++) {
2877 if (cpu_map[j] & (1UL << k)) {
2878 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2879 }
2880 }
2881 }
2882 }
2883 }
2884 }
2885 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2886 }
2887
2888 int os::Linux::get_node_by_cpu(int cpu_id) {
2889 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2890 return cpu_to_node()->at(cpu_id);
2891 }
2892 return -1;
2893 }
2894
2895 GrowableArray<int>* os::Linux::_cpu_to_node;
2896 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2897 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2898 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2899 os::Linux::numa_available_func_t os::Linux::_numa_available;
2900 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2901 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2902 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2903 unsigned long* os::Linux::_numa_all_nodes;
2904
2905 bool os::pd_uncommit_memory(char* addr, size_t size) {
2906 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2907 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2908 return res != (uintptr_t) MAP_FAILED;
2909 }
2910
2911 static address get_stack_commited_bottom(address bottom, size_t size) {
2912 address nbot = bottom;
2913 address ntop = bottom + size;
2914
2915 size_t page_sz = os::vm_page_size();
2916 unsigned pages = size / page_sz;
2917
2918 unsigned char vec[1];
2919 unsigned imin = 1, imax = pages + 1, imid;
2920 int mincore_return_value = 0;
2921
2922 assert(imin <= imax, "Unexpected page size");
2923
2924 while (imin < imax) {
2925 imid = (imax + imin) / 2;
2926 nbot = ntop - (imid * page_sz);
2927
2928 // Use a trick with mincore to check whether the page is mapped or not.
2929 // mincore sets vec to 1 if page resides in memory and to 0 if page
2930 // is swapped output but if page we are asking for is unmapped
2931 // it returns -1,ENOMEM
2932 mincore_return_value = mincore(nbot, page_sz, vec);
2933
2934 if (mincore_return_value == -1) {
2935 // Page is not mapped go up
2936 // to find first mapped page
2937 if (errno != EAGAIN) {
2938 assert(errno == ENOMEM, "Unexpected mincore errno");
2939 imax = imid;
2940 }
2941 } else {
2942 // Page is mapped go down
2943 // to find first not mapped page
2944 imin = imid + 1;
2945 }
2946 }
2947
2948 nbot = nbot + page_sz;
2949
2950 // Adjust stack bottom one page up if last checked page is not mapped
2951 if (mincore_return_value == -1) {
2952 nbot = nbot + page_sz;
2953 }
2954
2955 return nbot;
2956 }
2957
2958
2959 // Linux uses a growable mapping for the stack, and if the mapping for
2960 // the stack guard pages is not removed when we detach a thread the
2961 // stack cannot grow beyond the pages where the stack guard was
2962 // mapped. If at some point later in the process the stack expands to
2963 // that point, the Linux kernel cannot expand the stack any further
2964 // because the guard pages are in the way, and a segfault occurs.
2965 //
2966 // However, it's essential not to split the stack region by unmapping
2967 // a region (leaving a hole) that's already part of the stack mapping,
2968 // so if the stack mapping has already grown beyond the guard pages at
2969 // the time we create them, we have to truncate the stack mapping.
2970 // So, we need to know the extent of the stack mapping when
2971 // create_stack_guard_pages() is called.
2972
2973 // We only need this for stacks that are growable: at the time of
2974 // writing thread stacks don't use growable mappings (i.e. those
2975 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2976 // only applies to the main thread.
2977
2978 // If the (growable) stack mapping already extends beyond the point
2979 // where we're going to put our guard pages, truncate the mapping at
2980 // that point by munmap()ping it. This ensures that when we later
2981 // munmap() the guard pages we don't leave a hole in the stack
2982 // mapping. This only affects the main/initial thread
2983
2984 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2985 if (os::Linux::is_initial_thread()) {
2986 // As we manually grow stack up to bottom inside create_attached_thread(),
2987 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
2988 // we don't need to do anything special.
2989 // Check it first, before calling heavy function.
2990 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
2991 unsigned char vec[1];
2992
2993 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
2994 // Fallback to slow path on all errors, including EAGAIN
2995 stack_extent = (uintptr_t) get_stack_commited_bottom(
2996 os::Linux::initial_thread_stack_bottom(),
2997 (size_t)addr - stack_extent);
2998 }
2999
3000 if (stack_extent < (uintptr_t)addr) {
3001 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3002 }
3003 }
3004
3005 return os::commit_memory(addr, size, !ExecMem);
3006 }
3007
3008 // If this is a growable mapping, remove the guard pages entirely by
3009 // munmap()ping them. If not, just call uncommit_memory(). This only
3010 // affects the main/initial thread, but guard against future OS changes
3011 // It's safe to always unmap guard pages for initial thread because we
3012 // always place it right after end of the mapped region
3013
3014 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3015 uintptr_t stack_extent, stack_base;
3016
3017 if (os::Linux::is_initial_thread()) {
3018 return ::munmap(addr, size) == 0;
3019 }
3020
3021 return os::uncommit_memory(addr, size);
3022 }
3023
3024 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3025 // at 'requested_addr'. If there are existing memory mappings at the same
3026 // location, however, they will be overwritten. If 'fixed' is false,
3027 // 'requested_addr' is only treated as a hint, the return value may or
3028 // may not start from the requested address. Unlike Linux mmap(), this
3029 // function returns NULL to indicate failure.
3030 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3031 char * addr;
3032 int flags;
3033
3034 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3035 if (fixed) {
3036 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3037 flags |= MAP_FIXED;
3038 }
3039
3040 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3041 // touch an uncommitted page. Otherwise, the read/write might
3042 // succeed if we have enough swap space to back the physical page.
3043 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3044 flags, -1, 0);
3045
3046 return addr == MAP_FAILED ? NULL : addr;
3047 }
3048
3049 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3050 // (req_addr != NULL) or with a given alignment.
3051 // - bytes shall be a multiple of alignment.
3052 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3053 // - alignment sets the alignment at which memory shall be allocated.
3054 // It must be a multiple of allocation granularity.
3055 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3056 // req_addr or NULL.
3057 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3058
3059 size_t extra_size = bytes;
3060 if (req_addr == NULL && alignment > 0) {
3061 extra_size += alignment;
3062 }
3063
3064 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3065 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3066 -1, 0);
3067 if (start == MAP_FAILED) {
3068 start = NULL;
3069 } else {
3070 if (req_addr != NULL) {
3071 if (start != req_addr) {
3072 ::munmap(start, extra_size);
3073 start = NULL;
3074 }
3075 } else {
3076 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3077 char* const end_aligned = start_aligned + bytes;
3078 char* const end = start + extra_size;
3079 if (start_aligned > start) {
3080 ::munmap(start, start_aligned - start);
3081 }
3082 if (end_aligned < end) {
3083 ::munmap(end_aligned, end - end_aligned);
3084 }
3085 start = start_aligned;
3086 }
3087 }
3088 return start;
3089 }
3090
3091 static int anon_munmap(char * addr, size_t size) {
3092 return ::munmap(addr, size) == 0;
3093 }
3094
3095 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3096 size_t alignment_hint) {
3097 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3098 }
3099
3100 bool os::pd_release_memory(char* addr, size_t size) {
3101 return anon_munmap(addr, size);
3102 }
3103
3104 static bool linux_mprotect(char* addr, size_t size, int prot) {
3105 // Linux wants the mprotect address argument to be page aligned.
3106 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3107
3108 // According to SUSv3, mprotect() should only be used with mappings
3109 // established by mmap(), and mmap() always maps whole pages. Unaligned
3110 // 'addr' likely indicates problem in the VM (e.g. trying to change
3111 // protection of malloc'ed or statically allocated memory). Check the
3112 // caller if you hit this assert.
3113 assert(addr == bottom, "sanity check");
3114
3115 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3116 return ::mprotect(bottom, size, prot) == 0;
3117 }
3118
3119 // Set protections specified
3120 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3121 bool is_committed) {
3122 unsigned int p = 0;
3123 switch (prot) {
3124 case MEM_PROT_NONE: p = PROT_NONE; break;
3125 case MEM_PROT_READ: p = PROT_READ; break;
3126 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3127 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3128 default:
3129 ShouldNotReachHere();
3130 }
3131 // is_committed is unused.
3132 return linux_mprotect(addr, bytes, p);
3133 }
3134
3135 bool os::guard_memory(char* addr, size_t size) {
3136 return linux_mprotect(addr, size, PROT_NONE);
3137 }
3138
3139 bool os::unguard_memory(char* addr, size_t size) {
3140 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3141 }
3142
3143 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3144 size_t page_size) {
3145 bool result = false;
3146 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3147 MAP_ANONYMOUS|MAP_PRIVATE,
3148 -1, 0);
3149 if (p != MAP_FAILED) {
3150 void *aligned_p = align_ptr_up(p, page_size);
3151
3152 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3153
3154 munmap(p, page_size * 2);
3155 }
3156
3157 if (warn && !result) {
3158 warning("TransparentHugePages is not supported by the operating system.");
3159 }
3160
3161 return result;
3162 }
3163
3164 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3165 bool result = false;
3166 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3167 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3168 -1, 0);
3169
3170 if (p != MAP_FAILED) {
3171 // We don't know if this really is a huge page or not.
3172 FILE *fp = fopen("/proc/self/maps", "r");
3173 if (fp) {
3174 while (!feof(fp)) {
3175 char chars[257];
3176 long x = 0;
3177 if (fgets(chars, sizeof(chars), fp)) {
3178 if (sscanf(chars, "%lx-%*x", &x) == 1
3179 && x == (long)p) {
3180 if (strstr (chars, "hugepage")) {
3181 result = true;
3182 break;
3183 }
3184 }
3185 }
3186 }
3187 fclose(fp);
3188 }
3189 munmap(p, page_size);
3190 }
3191
3192 if (warn && !result) {
3193 warning("HugeTLBFS is not supported by the operating system.");
3194 }
3195
3196 return result;
3197 }
3198
3199 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3200 //
3201 // From the coredump_filter documentation:
3202 //
3203 // - (bit 0) anonymous private memory
3204 // - (bit 1) anonymous shared memory
3205 // - (bit 2) file-backed private memory
3206 // - (bit 3) file-backed shared memory
3207 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3208 // effective only if the bit 2 is cleared)
3209 // - (bit 5) hugetlb private memory
3210 // - (bit 6) hugetlb shared memory
3211 //
3212 static void set_coredump_filter(void) {
3213 FILE *f;
3214 long cdm;
3215
3216 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3217 return;
3218 }
3219
3220 if (fscanf(f, "%lx", &cdm) != 1) {
3221 fclose(f);
3222 return;
3223 }
3224
3225 rewind(f);
3226
3227 if ((cdm & LARGEPAGES_BIT) == 0) {
3228 cdm |= LARGEPAGES_BIT;
3229 fprintf(f, "%#lx", cdm);
3230 }
3231
3232 fclose(f);
3233 }
3234
3235 // Large page support
3236
3237 static size_t _large_page_size = 0;
3238
3239 size_t os::Linux::find_large_page_size() {
3240 size_t large_page_size = 0;
3241
3242 // large_page_size on Linux is used to round up heap size. x86 uses either
3243 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3244 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3245 // page as large as 256M.
3246 //
3247 // Here we try to figure out page size by parsing /proc/meminfo and looking
3248 // for a line with the following format:
3249 // Hugepagesize: 2048 kB
3250 //
3251 // If we can't determine the value (e.g. /proc is not mounted, or the text
3252 // format has been changed), we'll use the largest page size supported by
3253 // the processor.
3254
3255 #ifndef ZERO
3256 large_page_size =
3257 AARCH64_ONLY(2 * M)
3258 AMD64_ONLY(2 * M)
3259 ARM32_ONLY(2 * M)
3260 IA32_ONLY(4 * M)
3261 IA64_ONLY(256 * M)
3262 PPC_ONLY(4 * M)
3263 S390_ONLY(1 * M)
3264 SPARC_ONLY(4 * M);
3265 #endif // ZERO
3266
3267 FILE *fp = fopen("/proc/meminfo", "r");
3268 if (fp) {
3269 while (!feof(fp)) {
3270 int x = 0;
3271 char buf[16];
3272 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3273 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3274 large_page_size = x * K;
3275 break;
3276 }
3277 } else {
3278 // skip to next line
3279 for (;;) {
3280 int ch = fgetc(fp);
3281 if (ch == EOF || ch == (int)'\n') break;
3282 }
3283 }
3284 }
3285 fclose(fp);
3286 }
3287
3288 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3289 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3290 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3291 proper_unit_for_byte_size(large_page_size));
3292 }
3293
3294 return large_page_size;
3295 }
3296
3297 size_t os::Linux::setup_large_page_size() {
3298 _large_page_size = Linux::find_large_page_size();
3299 const size_t default_page_size = (size_t)Linux::page_size();
3300 if (_large_page_size > default_page_size) {
3301 _page_sizes[0] = _large_page_size;
3302 _page_sizes[1] = default_page_size;
3303 _page_sizes[2] = 0;
3304 }
3305
3306 return _large_page_size;
3307 }
3308
3309 bool os::Linux::setup_large_page_type(size_t page_size) {
3310 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3311 FLAG_IS_DEFAULT(UseSHM) &&
3312 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3313
3314 // The type of large pages has not been specified by the user.
3315
3316 // Try UseHugeTLBFS and then UseSHM.
3317 UseHugeTLBFS = UseSHM = true;
3318
3319 // Don't try UseTransparentHugePages since there are known
3320 // performance issues with it turned on. This might change in the future.
3321 UseTransparentHugePages = false;
3322 }
3323
3324 if (UseTransparentHugePages) {
3325 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3326 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3327 UseHugeTLBFS = false;
3328 UseSHM = false;
3329 return true;
3330 }
3331 UseTransparentHugePages = false;
3332 }
3333
3334 if (UseHugeTLBFS) {
3335 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3336 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3337 UseSHM = false;
3338 return true;
3339 }
3340 UseHugeTLBFS = false;
3341 }
3342
3343 return UseSHM;
3344 }
3345
3346 void os::large_page_init() {
3347 if (!UseLargePages &&
3348 !UseTransparentHugePages &&
3349 !UseHugeTLBFS &&
3350 !UseSHM) {
3351 // Not using large pages.
3352 return;
3353 }
3354
3355 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3356 // The user explicitly turned off large pages.
3357 // Ignore the rest of the large pages flags.
3358 UseTransparentHugePages = false;
3359 UseHugeTLBFS = false;
3360 UseSHM = false;
3361 return;
3362 }
3363
3364 size_t large_page_size = Linux::setup_large_page_size();
3365 UseLargePages = Linux::setup_large_page_type(large_page_size);
3366
3367 set_coredump_filter();
3368 }
3369
3370 #ifndef SHM_HUGETLB
3371 #define SHM_HUGETLB 04000
3372 #endif
3373
3374 #define shm_warning_format(format, ...) \
3375 do { \
3376 if (UseLargePages && \
3377 (!FLAG_IS_DEFAULT(UseLargePages) || \
3378 !FLAG_IS_DEFAULT(UseSHM) || \
3379 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3380 warning(format, __VA_ARGS__); \
3381 } \
3382 } while (0)
3383
3384 #define shm_warning(str) shm_warning_format("%s", str)
3385
3386 #define shm_warning_with_errno(str) \
3387 do { \
3388 int err = errno; \
3389 shm_warning_format(str " (error = %d)", err); \
3390 } while (0)
3391
3392 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3393 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3394
3395 if (!is_size_aligned(alignment, SHMLBA)) {
3396 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3397 return NULL;
3398 }
3399
3400 // To ensure that we get 'alignment' aligned memory from shmat,
3401 // we pre-reserve aligned virtual memory and then attach to that.
3402
3403 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3404 if (pre_reserved_addr == NULL) {
3405 // Couldn't pre-reserve aligned memory.
3406 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3407 return NULL;
3408 }
3409
3410 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3411 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3412
3413 if ((intptr_t)addr == -1) {
3414 int err = errno;
3415 shm_warning_with_errno("Failed to attach shared memory.");
3416
3417 assert(err != EACCES, "Unexpected error");
3418 assert(err != EIDRM, "Unexpected error");
3419 assert(err != EINVAL, "Unexpected error");
3420
3421 // Since we don't know if the kernel unmapped the pre-reserved memory area
3422 // we can't unmap it, since that would potentially unmap memory that was
3423 // mapped from other threads.
3424 return NULL;
3425 }
3426
3427 return addr;
3428 }
3429
3430 static char* shmat_at_address(int shmid, char* req_addr) {
3431 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3432 assert(false, "Requested address needs to be SHMLBA aligned");
3433 return NULL;
3434 }
3435
3436 char* addr = (char*)shmat(shmid, req_addr, 0);
3437
3438 if ((intptr_t)addr == -1) {
3439 shm_warning_with_errno("Failed to attach shared memory.");
3440 return NULL;
3441 }
3442
3443 return addr;
3444 }
3445
3446 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3447 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3448 if (req_addr != NULL) {
3449 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3450 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3451 return shmat_at_address(shmid, req_addr);
3452 }
3453
3454 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3455 // return large page size aligned memory addresses when req_addr == NULL.
3456 // However, if the alignment is larger than the large page size, we have
3457 // to manually ensure that the memory returned is 'alignment' aligned.
3458 if (alignment > os::large_page_size()) {
3459 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3460 return shmat_with_alignment(shmid, bytes, alignment);
3461 } else {
3462 return shmat_at_address(shmid, NULL);
3463 }
3464 }
3465
3466 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3467 char* req_addr, bool exec) {
3468 // "exec" is passed in but not used. Creating the shared image for
3469 // the code cache doesn't have an SHM_X executable permission to check.
3470 assert(UseLargePages && UseSHM, "only for SHM large pages");
3471 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3472 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3473
3474 if (!is_size_aligned(bytes, os::large_page_size())) {
3475 return NULL; // Fallback to small pages.
3476 }
3477
3478 // Create a large shared memory region to attach to based on size.
3479 // Currently, size is the total size of the heap.
3480 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3481 if (shmid == -1) {
3482 // Possible reasons for shmget failure:
3483 // 1. shmmax is too small for Java heap.
3484 // > check shmmax value: cat /proc/sys/kernel/shmmax
3485 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3486 // 2. not enough large page memory.
3487 // > check available large pages: cat /proc/meminfo
3488 // > increase amount of large pages:
3489 // echo new_value > /proc/sys/vm/nr_hugepages
3490 // Note 1: different Linux may use different name for this property,
3491 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3492 // Note 2: it's possible there's enough physical memory available but
3493 // they are so fragmented after a long run that they can't
3494 // coalesce into large pages. Try to reserve large pages when
3495 // the system is still "fresh".
3496 shm_warning_with_errno("Failed to reserve shared memory.");
3497 return NULL;
3498 }
3499
3500 // Attach to the region.
3501 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3502
3503 // Remove shmid. If shmat() is successful, the actual shared memory segment
3504 // will be deleted when it's detached by shmdt() or when the process
3505 // terminates. If shmat() is not successful this will remove the shared
3506 // segment immediately.
3507 shmctl(shmid, IPC_RMID, NULL);
3508
3509 return addr;
3510 }
3511
3512 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3513 int error) {
3514 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3515
3516 bool warn_on_failure = UseLargePages &&
3517 (!FLAG_IS_DEFAULT(UseLargePages) ||
3518 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3519 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3520
3521 if (warn_on_failure) {
3522 char msg[128];
3523 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3524 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3525 warning("%s", msg);
3526 }
3527 }
3528
3529 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3530 char* req_addr,
3531 bool exec) {
3532 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3533 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3534 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3535
3536 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3537 char* addr = (char*)::mmap(req_addr, bytes, prot,
3538 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3539 -1, 0);
3540
3541 if (addr == MAP_FAILED) {
3542 warn_on_large_pages_failure(req_addr, bytes, errno);
3543 return NULL;
3544 }
3545
3546 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3547
3548 return addr;
3549 }
3550
3551 // Reserve memory using mmap(MAP_HUGETLB).
3552 // - bytes shall be a multiple of alignment.
3553 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3554 // - alignment sets the alignment at which memory shall be allocated.
3555 // It must be a multiple of allocation granularity.
3556 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3557 // req_addr or NULL.
3558 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3559 size_t alignment,
3560 char* req_addr,
3561 bool exec) {
3562 size_t large_page_size = os::large_page_size();
3563 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3564
3565 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3566 assert(is_size_aligned(bytes, alignment), "Must be");
3567
3568 // First reserve - but not commit - the address range in small pages.
3569 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3570
3571 if (start == NULL) {
3572 return NULL;
3573 }
3574
3575 assert(is_ptr_aligned(start, alignment), "Must be");
3576
3577 char* end = start + bytes;
3578
3579 // Find the regions of the allocated chunk that can be promoted to large pages.
3580 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3581 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3582
3583 size_t lp_bytes = lp_end - lp_start;
3584
3585 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3586
3587 if (lp_bytes == 0) {
3588 // The mapped region doesn't even span the start and the end of a large page.
3589 // Fall back to allocate a non-special area.
3590 ::munmap(start, end - start);
3591 return NULL;
3592 }
3593
3594 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3595
3596 void* result;
3597
3598 // Commit small-paged leading area.
3599 if (start != lp_start) {
3600 result = ::mmap(start, lp_start - start, prot,
3601 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3602 -1, 0);
3603 if (result == MAP_FAILED) {
3604 ::munmap(lp_start, end - lp_start);
3605 return NULL;
3606 }
3607 }
3608
3609 // Commit large-paged area.
3610 result = ::mmap(lp_start, lp_bytes, prot,
3611 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3612 -1, 0);
3613 if (result == MAP_FAILED) {
3614 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3615 // If the mmap above fails, the large pages region will be unmapped and we
3616 // have regions before and after with small pages. Release these regions.
3617 //
3618 // | mapped | unmapped | mapped |
3619 // ^ ^ ^ ^
3620 // start lp_start lp_end end
3621 //
3622 ::munmap(start, lp_start - start);
3623 ::munmap(lp_end, end - lp_end);
3624 return NULL;
3625 }
3626
3627 // Commit small-paged trailing area.
3628 if (lp_end != end) {
3629 result = ::mmap(lp_end, end - lp_end, prot,
3630 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3631 -1, 0);
3632 if (result == MAP_FAILED) {
3633 ::munmap(start, lp_end - start);
3634 return NULL;
3635 }
3636 }
3637
3638 return start;
3639 }
3640
3641 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3642 size_t alignment,
3643 char* req_addr,
3644 bool exec) {
3645 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3646 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3647 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3648 assert(is_power_of_2(os::large_page_size()), "Must be");
3649 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3650
3651 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3652 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3653 } else {
3654 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3655 }
3656 }
3657
3658 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3659 char* req_addr, bool exec) {
3660 assert(UseLargePages, "only for large pages");
3661
3662 char* addr;
3663 if (UseSHM) {
3664 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3665 } else {
3666 assert(UseHugeTLBFS, "must be");
3667 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3668 }
3669
3670 if (addr != NULL) {
3671 if (UseNUMAInterleaving) {
3672 numa_make_global(addr, bytes);
3673 }
3674
3675 // The memory is committed
3676 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3677 }
3678
3679 return addr;
3680 }
3681
3682 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3683 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3684 return shmdt(base) == 0;
3685 }
3686
3687 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3688 return pd_release_memory(base, bytes);
3689 }
3690
3691 bool os::release_memory_special(char* base, size_t bytes) {
3692 bool res;
3693 if (MemTracker::tracking_level() > NMT_minimal) {
3694 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3695 res = os::Linux::release_memory_special_impl(base, bytes);
3696 if (res) {
3697 tkr.record((address)base, bytes);
3698 }
3699
3700 } else {
3701 res = os::Linux::release_memory_special_impl(base, bytes);
3702 }
3703 return res;
3704 }
3705
3706 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3707 assert(UseLargePages, "only for large pages");
3708 bool res;
3709
3710 if (UseSHM) {
3711 res = os::Linux::release_memory_special_shm(base, bytes);
3712 } else {
3713 assert(UseHugeTLBFS, "must be");
3714 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3715 }
3716 return res;
3717 }
3718
3719 size_t os::large_page_size() {
3720 return _large_page_size;
3721 }
3722
3723 // With SysV SHM the entire memory region must be allocated as shared
3724 // memory.
3725 // HugeTLBFS allows application to commit large page memory on demand.
3726 // However, when committing memory with HugeTLBFS fails, the region
3727 // that was supposed to be committed will lose the old reservation
3728 // and allow other threads to steal that memory region. Because of this
3729 // behavior we can't commit HugeTLBFS memory.
3730 bool os::can_commit_large_page_memory() {
3731 return UseTransparentHugePages;
3732 }
3733
3734 bool os::can_execute_large_page_memory() {
3735 return UseTransparentHugePages || UseHugeTLBFS;
3736 }
3737
3738 // Reserve memory at an arbitrary address, only if that area is
3739 // available (and not reserved for something else).
3740
3741 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3742 const int max_tries = 10;
3743 char* base[max_tries];
3744 size_t size[max_tries];
3745 const size_t gap = 0x000000;
3746
3747 // Assert only that the size is a multiple of the page size, since
3748 // that's all that mmap requires, and since that's all we really know
3749 // about at this low abstraction level. If we need higher alignment,
3750 // we can either pass an alignment to this method or verify alignment
3751 // in one of the methods further up the call chain. See bug 5044738.
3752 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3753
3754 // Repeatedly allocate blocks until the block is allocated at the
3755 // right spot.
3756
3757 // Linux mmap allows caller to pass an address as hint; give it a try first,
3758 // if kernel honors the hint then we can return immediately.
3759 char * addr = anon_mmap(requested_addr, bytes, false);
3760 if (addr == requested_addr) {
3761 return requested_addr;
3762 }
3763
3764 if (addr != NULL) {
3765 // mmap() is successful but it fails to reserve at the requested address
3766 anon_munmap(addr, bytes);
3767 }
3768
3769 int i;
3770 for (i = 0; i < max_tries; ++i) {
3771 base[i] = reserve_memory(bytes);
3772
3773 if (base[i] != NULL) {
3774 // Is this the block we wanted?
3775 if (base[i] == requested_addr) {
3776 size[i] = bytes;
3777 break;
3778 }
3779
3780 // Does this overlap the block we wanted? Give back the overlapped
3781 // parts and try again.
3782
3783 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3784 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3785 unmap_memory(base[i], top_overlap);
3786 base[i] += top_overlap;
3787 size[i] = bytes - top_overlap;
3788 } else {
3789 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3790 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3791 unmap_memory(requested_addr, bottom_overlap);
3792 size[i] = bytes - bottom_overlap;
3793 } else {
3794 size[i] = bytes;
3795 }
3796 }
3797 }
3798 }
3799
3800 // Give back the unused reserved pieces.
3801
3802 for (int j = 0; j < i; ++j) {
3803 if (base[j] != NULL) {
3804 unmap_memory(base[j], size[j]);
3805 }
3806 }
3807
3808 if (i < max_tries) {
3809 return requested_addr;
3810 } else {
3811 return NULL;
3812 }
3813 }
3814
3815 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3816 return ::read(fd, buf, nBytes);
3817 }
3818
3819 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3820 return ::pread(fd, buf, nBytes, offset);
3821 }
3822
3823 // Short sleep, direct OS call.
3824 //
3825 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3826 // sched_yield(2) will actually give up the CPU:
3827 //
3828 // * Alone on this pariticular CPU, keeps running.
3829 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3830 // (pre 2.6.39).
3831 //
3832 // So calling this with 0 is an alternative.
3833 //
3834 void os::naked_short_sleep(jlong ms) {
3835 struct timespec req;
3836
3837 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3838 req.tv_sec = 0;
3839 if (ms > 0) {
3840 req.tv_nsec = (ms % 1000) * 1000000;
3841 } else {
3842 req.tv_nsec = 1;
3843 }
3844
3845 nanosleep(&req, NULL);
3846
3847 return;
3848 }
3849
3850 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3851 void os::infinite_sleep() {
3852 while (true) { // sleep forever ...
3853 ::sleep(100); // ... 100 seconds at a time
3854 }
3855 }
3856
3857 // Used to convert frequent JVM_Yield() to nops
3858 bool os::dont_yield() {
3859 return DontYieldALot;
3860 }
3861
3862 void os::naked_yield() {
3863 sched_yield();
3864 }
3865
3866 ////////////////////////////////////////////////////////////////////////////////
3867 // thread priority support
3868
3869 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3870 // only supports dynamic priority, static priority must be zero. For real-time
3871 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3872 // However, for large multi-threaded applications, SCHED_RR is not only slower
3873 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3874 // of 5 runs - Sep 2005).
3875 //
3876 // The following code actually changes the niceness of kernel-thread/LWP. It
3877 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3878 // not the entire user process, and user level threads are 1:1 mapped to kernel
3879 // threads. It has always been the case, but could change in the future. For
3880 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3881 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3882
3883 int os::java_to_os_priority[CriticalPriority + 1] = {
3884 19, // 0 Entry should never be used
3885
3886 4, // 1 MinPriority
3887 3, // 2
3888 2, // 3
3889
3890 1, // 4
3891 0, // 5 NormPriority
3892 -1, // 6
3893
3894 -2, // 7
3895 -3, // 8
3896 -4, // 9 NearMaxPriority
3897
3898 -5, // 10 MaxPriority
3899
3900 -5 // 11 CriticalPriority
3901 };
3902
3903 static int prio_init() {
3904 if (ThreadPriorityPolicy == 1) {
3905 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3906 // if effective uid is not root. Perhaps, a more elegant way of doing
3907 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3908 if (geteuid() != 0) {
3909 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3910 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3911 }
3912 ThreadPriorityPolicy = 0;
3913 }
3914 }
3915 if (UseCriticalJavaThreadPriority) {
3916 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3917 }
3918 return 0;
3919 }
3920
3921 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3922 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3923
3924 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3925 return (ret == 0) ? OS_OK : OS_ERR;
3926 }
3927
3928 OSReturn os::get_native_priority(const Thread* const thread,
3929 int *priority_ptr) {
3930 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3931 *priority_ptr = java_to_os_priority[NormPriority];
3932 return OS_OK;
3933 }
3934
3935 errno = 0;
3936 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3937 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3938 }
3939
3940 // Hint to the underlying OS that a task switch would not be good.
3941 // Void return because it's a hint and can fail.
3942 void os::hint_no_preempt() {}
3943
3944 ////////////////////////////////////////////////////////////////////////////////
3945 // suspend/resume support
3946
3947 // the low-level signal-based suspend/resume support is a remnant from the
3948 // old VM-suspension that used to be for java-suspension, safepoints etc,
3949 // within hotspot. Now there is a single use-case for this:
3950 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3951 // that runs in the watcher thread.
3952 // The remaining code is greatly simplified from the more general suspension
3953 // code that used to be used.
3954 //
3955 // The protocol is quite simple:
3956 // - suspend:
3957 // - sends a signal to the target thread
3958 // - polls the suspend state of the osthread using a yield loop
3959 // - target thread signal handler (SR_handler) sets suspend state
3960 // and blocks in sigsuspend until continued
3961 // - resume:
3962 // - sets target osthread state to continue
3963 // - sends signal to end the sigsuspend loop in the SR_handler
3964 //
3965 // Note that the SR_lock plays no role in this suspend/resume protocol,
3966 // but is checked for NULL in SR_handler as a thread termination indicator.
3967
3968 static void resume_clear_context(OSThread *osthread) {
3969 osthread->set_ucontext(NULL);
3970 osthread->set_siginfo(NULL);
3971 }
3972
3973 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
3974 ucontext_t* context) {
3975 osthread->set_ucontext(context);
3976 osthread->set_siginfo(siginfo);
3977 }
3978
3979 // Handler function invoked when a thread's execution is suspended or
3980 // resumed. We have to be careful that only async-safe functions are
3981 // called here (Note: most pthread functions are not async safe and
3982 // should be avoided.)
3983 //
3984 // Note: sigwait() is a more natural fit than sigsuspend() from an
3985 // interface point of view, but sigwait() prevents the signal hander
3986 // from being run. libpthread would get very confused by not having
3987 // its signal handlers run and prevents sigwait()'s use with the
3988 // mutex granting granting signal.
3989 //
3990 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3991 //
3992 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3993 // Save and restore errno to avoid confusing native code with EINTR
3994 // after sigsuspend.
3995 int old_errno = errno;
3996
3997 Thread* thread = Thread::current_or_null_safe();
3998 assert(thread != NULL, "Missing current thread in SR_handler");
3999
4000 // On some systems we have seen signal delivery get "stuck" until the signal
4001 // mask is changed as part of thread termination. Check that the current thread
4002 // has not already terminated (via SR_lock()) - else the following assertion
4003 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4004 // destructor has completed.
4005
4006 if (thread->SR_lock() == NULL) {
4007 return;
4008 }
4009
4010 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4011
4012 OSThread* osthread = thread->osthread();
4013
4014 os::SuspendResume::State current = osthread->sr.state();
4015 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4016 suspend_save_context(osthread, siginfo, context);
4017
4018 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4019 os::SuspendResume::State state = osthread->sr.suspended();
4020 if (state == os::SuspendResume::SR_SUSPENDED) {
4021 sigset_t suspend_set; // signals for sigsuspend()
4022 sigemptyset(&suspend_set);
4023 // get current set of blocked signals and unblock resume signal
4024 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4025 sigdelset(&suspend_set, SR_signum);
4026
4027 sr_semaphore.signal();
4028 // wait here until we are resumed
4029 while (1) {
4030 sigsuspend(&suspend_set);
4031
4032 os::SuspendResume::State result = osthread->sr.running();
4033 if (result == os::SuspendResume::SR_RUNNING) {
4034 sr_semaphore.signal();
4035 break;
4036 }
4037 }
4038
4039 } else if (state == os::SuspendResume::SR_RUNNING) {
4040 // request was cancelled, continue
4041 } else {
4042 ShouldNotReachHere();
4043 }
4044
4045 resume_clear_context(osthread);
4046 } else if (current == os::SuspendResume::SR_RUNNING) {
4047 // request was cancelled, continue
4048 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4049 // ignore
4050 } else {
4051 // ignore
4052 }
4053
4054 errno = old_errno;
4055 }
4056
4057 static int SR_initialize() {
4058 struct sigaction act;
4059 char *s;
4060
4061 // Get signal number to use for suspend/resume
4062 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4063 int sig = ::strtol(s, 0, 10);
4064 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4065 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4066 SR_signum = sig;
4067 } else {
4068 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4069 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4070 }
4071 }
4072
4073 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4074 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4075
4076 sigemptyset(&SR_sigset);
4077 sigaddset(&SR_sigset, SR_signum);
4078
4079 // Set up signal handler for suspend/resume
4080 act.sa_flags = SA_RESTART|SA_SIGINFO;
4081 act.sa_handler = (void (*)(int)) SR_handler;
4082
4083 // SR_signum is blocked by default.
4084 // 4528190 - We also need to block pthread restart signal (32 on all
4085 // supported Linux platforms). Note that LinuxThreads need to block
4086 // this signal for all threads to work properly. So we don't have
4087 // to use hard-coded signal number when setting up the mask.
4088 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4089
4090 if (sigaction(SR_signum, &act, 0) == -1) {
4091 return -1;
4092 }
4093
4094 // Save signal flag
4095 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4096 return 0;
4097 }
4098
4099 static int sr_notify(OSThread* osthread) {
4100 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4101 assert_status(status == 0, status, "pthread_kill");
4102 return status;
4103 }
4104
4105 // "Randomly" selected value for how long we want to spin
4106 // before bailing out on suspending a thread, also how often
4107 // we send a signal to a thread we want to resume
4108 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4109 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4110
4111 // returns true on success and false on error - really an error is fatal
4112 // but this seems the normal response to library errors
4113 static bool do_suspend(OSThread* osthread) {
4114 assert(osthread->sr.is_running(), "thread should be running");
4115 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4116
4117 // mark as suspended and send signal
4118 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4119 // failed to switch, state wasn't running?
4120 ShouldNotReachHere();
4121 return false;
4122 }
4123
4124 if (sr_notify(osthread) != 0) {
4125 ShouldNotReachHere();
4126 }
4127
4128 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4129 while (true) {
4130 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4131 break;
4132 } else {
4133 // timeout
4134 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4135 if (cancelled == os::SuspendResume::SR_RUNNING) {
4136 return false;
4137 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4138 // make sure that we consume the signal on the semaphore as well
4139 sr_semaphore.wait();
4140 break;
4141 } else {
4142 ShouldNotReachHere();
4143 return false;
4144 }
4145 }
4146 }
4147
4148 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4149 return true;
4150 }
4151
4152 static void do_resume(OSThread* osthread) {
4153 assert(osthread->sr.is_suspended(), "thread should be suspended");
4154 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4155
4156 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4157 // failed to switch to WAKEUP_REQUEST
4158 ShouldNotReachHere();
4159 return;
4160 }
4161
4162 while (true) {
4163 if (sr_notify(osthread) == 0) {
4164 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4165 if (osthread->sr.is_running()) {
4166 return;
4167 }
4168 }
4169 } else {
4170 ShouldNotReachHere();
4171 }
4172 }
4173
4174 guarantee(osthread->sr.is_running(), "Must be running!");
4175 }
4176
4177 ///////////////////////////////////////////////////////////////////////////////////
4178 // signal handling (except suspend/resume)
4179
4180 // This routine may be used by user applications as a "hook" to catch signals.
4181 // The user-defined signal handler must pass unrecognized signals to this
4182 // routine, and if it returns true (non-zero), then the signal handler must
4183 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4184 // routine will never retun false (zero), but instead will execute a VM panic
4185 // routine kill the process.
4186 //
4187 // If this routine returns false, it is OK to call it again. This allows
4188 // the user-defined signal handler to perform checks either before or after
4189 // the VM performs its own checks. Naturally, the user code would be making
4190 // a serious error if it tried to handle an exception (such as a null check
4191 // or breakpoint) that the VM was generating for its own correct operation.
4192 //
4193 // This routine may recognize any of the following kinds of signals:
4194 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4195 // It should be consulted by handlers for any of those signals.
4196 //
4197 // The caller of this routine must pass in the three arguments supplied
4198 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4199 // field of the structure passed to sigaction(). This routine assumes that
4200 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4201 //
4202 // Note that the VM will print warnings if it detects conflicting signal
4203 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4204 //
4205 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4206 siginfo_t* siginfo,
4207 void* ucontext,
4208 int abort_if_unrecognized);
4209
4210 void signalHandler(int sig, siginfo_t* info, void* uc) {
4211 assert(info != NULL && uc != NULL, "it must be old kernel");
4212 int orig_errno = errno; // Preserve errno value over signal handler.
4213 JVM_handle_linux_signal(sig, info, uc, true);
4214 errno = orig_errno;
4215 }
4216
4217
4218 // This boolean allows users to forward their own non-matching signals
4219 // to JVM_handle_linux_signal, harmlessly.
4220 bool os::Linux::signal_handlers_are_installed = false;
4221
4222 // For signal-chaining
4223 struct sigaction sigact[NSIG];
4224 uint64_t sigs = 0;
4225 #if (64 < NSIG-1)
4226 #error "Not all signals can be encoded in sigs. Adapt its type!"
4227 #endif
4228 bool os::Linux::libjsig_is_loaded = false;
4229 typedef struct sigaction *(*get_signal_t)(int);
4230 get_signal_t os::Linux::get_signal_action = NULL;
4231
4232 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4233 struct sigaction *actp = NULL;
4234
4235 if (libjsig_is_loaded) {
4236 // Retrieve the old signal handler from libjsig
4237 actp = (*get_signal_action)(sig);
4238 }
4239 if (actp == NULL) {
4240 // Retrieve the preinstalled signal handler from jvm
4241 actp = get_preinstalled_handler(sig);
4242 }
4243
4244 return actp;
4245 }
4246
4247 static bool call_chained_handler(struct sigaction *actp, int sig,
4248 siginfo_t *siginfo, void *context) {
4249 // Call the old signal handler
4250 if (actp->sa_handler == SIG_DFL) {
4251 // It's more reasonable to let jvm treat it as an unexpected exception
4252 // instead of taking the default action.
4253 return false;
4254 } else if (actp->sa_handler != SIG_IGN) {
4255 if ((actp->sa_flags & SA_NODEFER) == 0) {
4256 // automaticlly block the signal
4257 sigaddset(&(actp->sa_mask), sig);
4258 }
4259
4260 sa_handler_t hand = NULL;
4261 sa_sigaction_t sa = NULL;
4262 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4263 // retrieve the chained handler
4264 if (siginfo_flag_set) {
4265 sa = actp->sa_sigaction;
4266 } else {
4267 hand = actp->sa_handler;
4268 }
4269
4270 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4271 actp->sa_handler = SIG_DFL;
4272 }
4273
4274 // try to honor the signal mask
4275 sigset_t oset;
4276 sigemptyset(&oset);
4277 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4278
4279 // call into the chained handler
4280 if (siginfo_flag_set) {
4281 (*sa)(sig, siginfo, context);
4282 } else {
4283 (*hand)(sig);
4284 }
4285
4286 // restore the signal mask
4287 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4288 }
4289 // Tell jvm's signal handler the signal is taken care of.
4290 return true;
4291 }
4292
4293 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4294 bool chained = false;
4295 // signal-chaining
4296 if (UseSignalChaining) {
4297 struct sigaction *actp = get_chained_signal_action(sig);
4298 if (actp != NULL) {
4299 chained = call_chained_handler(actp, sig, siginfo, context);
4300 }
4301 }
4302 return chained;
4303 }
4304
4305 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4306 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4307 return &sigact[sig];
4308 }
4309 return NULL;
4310 }
4311
4312 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4313 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4314 sigact[sig] = oldAct;
4315 sigs |= (uint64_t)1 << (sig-1);
4316 }
4317
4318 // for diagnostic
4319 int sigflags[NSIG];
4320
4321 int os::Linux::get_our_sigflags(int sig) {
4322 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4323 return sigflags[sig];
4324 }
4325
4326 void os::Linux::set_our_sigflags(int sig, int flags) {
4327 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4328 if (sig > 0 && sig < NSIG) {
4329 sigflags[sig] = flags;
4330 }
4331 }
4332
4333 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4334 // Check for overwrite.
4335 struct sigaction oldAct;
4336 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4337
4338 void* oldhand = oldAct.sa_sigaction
4339 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4340 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4341 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4342 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4343 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4344 if (AllowUserSignalHandlers || !set_installed) {
4345 // Do not overwrite; user takes responsibility to forward to us.
4346 return;
4347 } else if (UseSignalChaining) {
4348 // save the old handler in jvm
4349 save_preinstalled_handler(sig, oldAct);
4350 // libjsig also interposes the sigaction() call below and saves the
4351 // old sigaction on it own.
4352 } else {
4353 fatal("Encountered unexpected pre-existing sigaction handler "
4354 "%#lx for signal %d.", (long)oldhand, sig);
4355 }
4356 }
4357
4358 struct sigaction sigAct;
4359 sigfillset(&(sigAct.sa_mask));
4360 sigAct.sa_handler = SIG_DFL;
4361 if (!set_installed) {
4362 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4363 } else {
4364 sigAct.sa_sigaction = signalHandler;
4365 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4366 }
4367 // Save flags, which are set by ours
4368 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4369 sigflags[sig] = sigAct.sa_flags;
4370
4371 int ret = sigaction(sig, &sigAct, &oldAct);
4372 assert(ret == 0, "check");
4373
4374 void* oldhand2 = oldAct.sa_sigaction
4375 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4376 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4377 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4378 }
4379
4380 // install signal handlers for signals that HotSpot needs to
4381 // handle in order to support Java-level exception handling.
4382
4383 void os::Linux::install_signal_handlers() {
4384 if (!signal_handlers_are_installed) {
4385 signal_handlers_are_installed = true;
4386
4387 // signal-chaining
4388 typedef void (*signal_setting_t)();
4389 signal_setting_t begin_signal_setting = NULL;
4390 signal_setting_t end_signal_setting = NULL;
4391 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4392 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4393 if (begin_signal_setting != NULL) {
4394 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4395 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4396 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4397 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4398 libjsig_is_loaded = true;
4399 assert(UseSignalChaining, "should enable signal-chaining");
4400 }
4401 if (libjsig_is_loaded) {
4402 // Tell libjsig jvm is setting signal handlers
4403 (*begin_signal_setting)();
4404 }
4405
4406 set_signal_handler(SIGSEGV, true);
4407 set_signal_handler(SIGPIPE, true);
4408 set_signal_handler(SIGBUS, true);
4409 set_signal_handler(SIGILL, true);
4410 set_signal_handler(SIGFPE, true);
4411 #if defined(PPC64)
4412 set_signal_handler(SIGTRAP, true);
4413 #endif
4414 set_signal_handler(SIGXFSZ, true);
4415
4416 if (libjsig_is_loaded) {
4417 // Tell libjsig jvm finishes setting signal handlers
4418 (*end_signal_setting)();
4419 }
4420
4421 // We don't activate signal checker if libjsig is in place, we trust ourselves
4422 // and if UserSignalHandler is installed all bets are off.
4423 // Log that signal checking is off only if -verbose:jni is specified.
4424 if (CheckJNICalls) {
4425 if (libjsig_is_loaded) {
4426 if (PrintJNIResolving) {
4427 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4428 }
4429 check_signals = false;
4430 }
4431 if (AllowUserSignalHandlers) {
4432 if (PrintJNIResolving) {
4433 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4434 }
4435 check_signals = false;
4436 }
4437 }
4438 }
4439 }
4440
4441 // This is the fastest way to get thread cpu time on Linux.
4442 // Returns cpu time (user+sys) for any thread, not only for current.
4443 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4444 // It might work on 2.6.10+ with a special kernel/glibc patch.
4445 // For reference, please, see IEEE Std 1003.1-2004:
4446 // http://www.unix.org/single_unix_specification
4447
4448 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4449 struct timespec tp;
4450 int rc = os::Linux::clock_gettime(clockid, &tp);
4451 assert(rc == 0, "clock_gettime is expected to return 0 code");
4452
4453 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4454 }
4455
4456 void os::Linux::initialize_os_info() {
4457 assert(_os_version == 0, "OS info already initialized");
4458
4459 struct utsname _uname;
4460
4461 uint32_t major;
4462 uint32_t minor;
4463 uint32_t fix;
4464
4465 int rc;
4466
4467 // Kernel version is unknown if
4468 // verification below fails.
4469 _os_version = 0x01000000;
4470
4471 rc = uname(&_uname);
4472 if (rc != -1) {
4473
4474 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4475 if (rc == 3) {
4476
4477 if (major < 256 && minor < 256 && fix < 256) {
4478 // Kernel version format is as expected,
4479 // set it overriding unknown state.
4480 _os_version = (major << 16) |
4481 (minor << 8 ) |
4482 (fix << 0 ) ;
4483 }
4484 }
4485 }
4486 }
4487
4488 uint32_t os::Linux::os_version() {
4489 assert(_os_version != 0, "not initialized");
4490 return _os_version & 0x00FFFFFF;
4491 }
4492
4493 bool os::Linux::os_version_is_known() {
4494 assert(_os_version != 0, "not initialized");
4495 return _os_version & 0x01000000 ? false : true;
4496 }
4497
4498 /////
4499 // glibc on Linux platform uses non-documented flag
4500 // to indicate, that some special sort of signal
4501 // trampoline is used.
4502 // We will never set this flag, and we should
4503 // ignore this flag in our diagnostic
4504 #ifdef SIGNIFICANT_SIGNAL_MASK
4505 #undef SIGNIFICANT_SIGNAL_MASK
4506 #endif
4507 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4508
4509 static const char* get_signal_handler_name(address handler,
4510 char* buf, int buflen) {
4511 int offset = 0;
4512 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4513 if (found) {
4514 // skip directory names
4515 const char *p1, *p2;
4516 p1 = buf;
4517 size_t len = strlen(os::file_separator());
4518 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4519 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4520 } else {
4521 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4522 }
4523 return buf;
4524 }
4525
4526 static void print_signal_handler(outputStream* st, int sig,
4527 char* buf, size_t buflen) {
4528 struct sigaction sa;
4529
4530 sigaction(sig, NULL, &sa);
4531
4532 // See comment for SIGNIFICANT_SIGNAL_MASK define
4533 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4534
4535 st->print("%s: ", os::exception_name(sig, buf, buflen));
4536
4537 address handler = (sa.sa_flags & SA_SIGINFO)
4538 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4539 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4540
4541 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4542 st->print("SIG_DFL");
4543 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4544 st->print("SIG_IGN");
4545 } else {
4546 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4547 }
4548
4549 st->print(", sa_mask[0]=");
4550 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4551
4552 address rh = VMError::get_resetted_sighandler(sig);
4553 // May be, handler was resetted by VMError?
4554 if (rh != NULL) {
4555 handler = rh;
4556 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4557 }
4558
4559 st->print(", sa_flags=");
4560 os::Posix::print_sa_flags(st, sa.sa_flags);
4561
4562 // Check: is it our handler?
4563 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4564 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4565 // It is our signal handler
4566 // check for flags, reset system-used one!
4567 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4568 st->print(
4569 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4570 os::Linux::get_our_sigflags(sig));
4571 }
4572 }
4573 st->cr();
4574 }
4575
4576
4577 #define DO_SIGNAL_CHECK(sig) \
4578 do { \
4579 if (!sigismember(&check_signal_done, sig)) { \
4580 os::Linux::check_signal_handler(sig); \
4581 } \
4582 } while (0)
4583
4584 // This method is a periodic task to check for misbehaving JNI applications
4585 // under CheckJNI, we can add any periodic checks here
4586
4587 void os::run_periodic_checks() {
4588 if (check_signals == false) return;
4589
4590 // SEGV and BUS if overridden could potentially prevent
4591 // generation of hs*.log in the event of a crash, debugging
4592 // such a case can be very challenging, so we absolutely
4593 // check the following for a good measure:
4594 DO_SIGNAL_CHECK(SIGSEGV);
4595 DO_SIGNAL_CHECK(SIGILL);
4596 DO_SIGNAL_CHECK(SIGFPE);
4597 DO_SIGNAL_CHECK(SIGBUS);
4598 DO_SIGNAL_CHECK(SIGPIPE);
4599 DO_SIGNAL_CHECK(SIGXFSZ);
4600 #if defined(PPC64)
4601 DO_SIGNAL_CHECK(SIGTRAP);
4602 #endif
4603
4604 // ReduceSignalUsage allows the user to override these handlers
4605 // see comments at the very top and jvm_solaris.h
4606 if (!ReduceSignalUsage) {
4607 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4608 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4609 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4610 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4611 }
4612
4613 DO_SIGNAL_CHECK(SR_signum);
4614 }
4615
4616 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4617
4618 static os_sigaction_t os_sigaction = NULL;
4619
4620 void os::Linux::check_signal_handler(int sig) {
4621 char buf[O_BUFLEN];
4622 address jvmHandler = NULL;
4623
4624
4625 struct sigaction act;
4626 if (os_sigaction == NULL) {
4627 // only trust the default sigaction, in case it has been interposed
4628 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4629 if (os_sigaction == NULL) return;
4630 }
4631
4632 os_sigaction(sig, (struct sigaction*)NULL, &act);
4633
4634
4635 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4636
4637 address thisHandler = (act.sa_flags & SA_SIGINFO)
4638 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4639 : CAST_FROM_FN_PTR(address, act.sa_handler);
4640
4641
4642 switch (sig) {
4643 case SIGSEGV:
4644 case SIGBUS:
4645 case SIGFPE:
4646 case SIGPIPE:
4647 case SIGILL:
4648 case SIGXFSZ:
4649 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4650 break;
4651
4652 case SHUTDOWN1_SIGNAL:
4653 case SHUTDOWN2_SIGNAL:
4654 case SHUTDOWN3_SIGNAL:
4655 case BREAK_SIGNAL:
4656 jvmHandler = (address)user_handler();
4657 break;
4658
4659 default:
4660 if (sig == SR_signum) {
4661 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4662 } else {
4663 return;
4664 }
4665 break;
4666 }
4667
4668 if (thisHandler != jvmHandler) {
4669 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4670 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4671 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4672 // No need to check this sig any longer
4673 sigaddset(&check_signal_done, sig);
4674 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4675 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4676 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4677 exception_name(sig, buf, O_BUFLEN));
4678 }
4679 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4680 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4681 tty->print("expected:");
4682 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4683 tty->cr();
4684 tty->print(" found:");
4685 os::Posix::print_sa_flags(tty, act.sa_flags);
4686 tty->cr();
4687 // No need to check this sig any longer
4688 sigaddset(&check_signal_done, sig);
4689 }
4690
4691 // Dump all the signal
4692 if (sigismember(&check_signal_done, sig)) {
4693 print_signal_handlers(tty, buf, O_BUFLEN);
4694 }
4695 }
4696
4697 extern void report_error(char* file_name, int line_no, char* title,
4698 char* format, ...);
4699
4700 // this is called _before_ the most of global arguments have been parsed
4701 void os::init(void) {
4702 char dummy; // used to get a guess on initial stack address
4703 // first_hrtime = gethrtime();
4704
4705 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4706
4707 init_random(1234567);
4708
4709 ThreadCritical::initialize();
4710
4711 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4712 if (Linux::page_size() == -1) {
4713 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4714 os::strerror(errno));
4715 }
4716 init_page_sizes((size_t) Linux::page_size());
4717
4718 Linux::initialize_system_info();
4719
4720 Linux::initialize_os_info();
4721
4722 // main_thread points to the aboriginal thread
4723 Linux::_main_thread = pthread_self();
4724
4725 Linux::clock_init();
4726 initial_time_count = javaTimeNanos();
4727
4728 // pthread_condattr initialization for monotonic clock
4729 int status;
4730 pthread_condattr_t* _condattr = os::Linux::condAttr();
4731 if ((status = pthread_condattr_init(_condattr)) != 0) {
4732 fatal("pthread_condattr_init: %s", os::strerror(status));
4733 }
4734 // Only set the clock if CLOCK_MONOTONIC is available
4735 if (os::supports_monotonic_clock()) {
4736 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4737 if (status == EINVAL) {
4738 warning("Unable to use monotonic clock with relative timed-waits" \
4739 " - changes to the time-of-day clock may have adverse affects");
4740 } else {
4741 fatal("pthread_condattr_setclock: %s", os::strerror(status));
4742 }
4743 }
4744 }
4745 // else it defaults to CLOCK_REALTIME
4746
4747 // retrieve entry point for pthread_setname_np
4748 Linux::_pthread_setname_np =
4749 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4750
4751 }
4752
4753 // To install functions for atexit system call
4754 extern "C" {
4755 static void perfMemory_exit_helper() {
4756 perfMemory_exit();
4757 }
4758 }
4759
4760 // this is called _after_ the global arguments have been parsed
4761 jint os::init_2(void) {
4762 Linux::fast_thread_clock_init();
4763
4764 // Allocate a single page and mark it as readable for safepoint polling
4765 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4766 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4767
4768 os::set_polling_page(polling_page);
4769 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4770
4771 if (!UseMembar) {
4772 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4773 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4774 os::set_memory_serialize_page(mem_serialize_page);
4775 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4776 }
4777
4778 // initialize suspend/resume support - must do this before signal_sets_init()
4779 if (SR_initialize() != 0) {
4780 perror("SR_initialize failed");
4781 return JNI_ERR;
4782 }
4783
4784 Linux::signal_sets_init();
4785 Linux::install_signal_handlers();
4786
4787 // Check and sets minimum stack sizes against command line options
4788 if (Posix::set_minimum_stack_sizes() == JNI_ERR) {
4789 return JNI_ERR;
4790 }
4791 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4792
4793 #if defined(IA32)
4794 workaround_expand_exec_shield_cs_limit();
4795 #endif
4796
4797 Linux::libpthread_init();
4798 log_info(os)("HotSpot is running with %s, %s",
4799 Linux::glibc_version(), Linux::libpthread_version());
4800
4801 if (UseNUMA) {
4802 if (!Linux::libnuma_init()) {
4803 UseNUMA = false;
4804 } else {
4805 if ((Linux::numa_max_node() < 1)) {
4806 // There's only one node(they start from 0), disable NUMA.
4807 UseNUMA = false;
4808 }
4809 }
4810 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4811 // we can make the adaptive lgrp chunk resizing work. If the user specified
4812 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4813 // disable adaptive resizing.
4814 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4815 if (FLAG_IS_DEFAULT(UseNUMA)) {
4816 UseNUMA = false;
4817 } else {
4818 if (FLAG_IS_DEFAULT(UseLargePages) &&
4819 FLAG_IS_DEFAULT(UseSHM) &&
4820 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4821 UseLargePages = false;
4822 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4823 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4824 UseAdaptiveSizePolicy = false;
4825 UseAdaptiveNUMAChunkSizing = false;
4826 }
4827 }
4828 }
4829 if (!UseNUMA && ForceNUMA) {
4830 UseNUMA = true;
4831 }
4832 }
4833
4834 if (MaxFDLimit) {
4835 // set the number of file descriptors to max. print out error
4836 // if getrlimit/setrlimit fails but continue regardless.
4837 struct rlimit nbr_files;
4838 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4839 if (status != 0) {
4840 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4841 } else {
4842 nbr_files.rlim_cur = nbr_files.rlim_max;
4843 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4844 if (status != 0) {
4845 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4846 }
4847 }
4848 }
4849
4850 // Initialize lock used to serialize thread creation (see os::create_thread)
4851 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4852
4853 // at-exit methods are called in the reverse order of their registration.
4854 // atexit functions are called on return from main or as a result of a
4855 // call to exit(3C). There can be only 32 of these functions registered
4856 // and atexit() does not set errno.
4857
4858 if (PerfAllowAtExitRegistration) {
4859 // only register atexit functions if PerfAllowAtExitRegistration is set.
4860 // atexit functions can be delayed until process exit time, which
4861 // can be problematic for embedded VM situations. Embedded VMs should
4862 // call DestroyJavaVM() to assure that VM resources are released.
4863
4864 // note: perfMemory_exit_helper atexit function may be removed in
4865 // the future if the appropriate cleanup code can be added to the
4866 // VM_Exit VMOperation's doit method.
4867 if (atexit(perfMemory_exit_helper) != 0) {
4868 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4869 }
4870 }
4871
4872 // initialize thread priority policy
4873 prio_init();
4874
4875 return JNI_OK;
4876 }
4877
4878 // Mark the polling page as unreadable
4879 void os::make_polling_page_unreadable(void) {
4880 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4881 fatal("Could not disable polling page");
4882 }
4883 }
4884
4885 // Mark the polling page as readable
4886 void os::make_polling_page_readable(void) {
4887 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4888 fatal("Could not enable polling page");
4889 }
4890 }
4891
4892 // older glibc versions don't have this macro (which expands to
4893 // an optimized bit-counting function) so we have to roll our own
4894 #ifndef CPU_COUNT
4895
4896 static int _cpu_count(const cpu_set_t* cpus) {
4897 int count = 0;
4898 // only look up to the number of configured processors
4899 for (int i = 0; i < os::processor_count(); i++) {
4900 if (CPU_ISSET(i, cpus)) {
4901 count++;
4902 }
4903 }
4904 return count;
4905 }
4906
4907 #define CPU_COUNT(cpus) _cpu_count(cpus)
4908
4909 #endif // CPU_COUNT
4910
4911 // Get the current number of available processors for this process.
4912 // This value can change at any time during a process's lifetime.
4913 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4914 // If it appears there may be more than 1024 processors then we do a
4915 // dynamic check - see 6515172 for details.
4916 // If anything goes wrong we fallback to returning the number of online
4917 // processors - which can be greater than the number available to the process.
4918 int os::active_processor_count() {
4919 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4920 cpu_set_t* cpus_p = &cpus;
4921 int cpus_size = sizeof(cpu_set_t);
4922
4923 int configured_cpus = processor_count(); // upper bound on available cpus
4924 int cpu_count = 0;
4925
4926 // old build platforms may not support dynamic cpu sets
4927 #ifdef CPU_ALLOC
4928
4929 // To enable easy testing of the dynamic path on different platforms we
4930 // introduce a diagnostic flag: UseCpuAllocPath
4931 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4932 // kernel may use a mask bigger than cpu_set_t
4933 log_trace(os)("active_processor_count: using dynamic path %s"
4934 "- configured processors: %d",
4935 UseCpuAllocPath ? "(forced) " : "",
4936 configured_cpus);
4937 cpus_p = CPU_ALLOC(configured_cpus);
4938 if (cpus_p != NULL) {
4939 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4940 // zero it just to be safe
4941 CPU_ZERO_S(cpus_size, cpus_p);
4942 }
4943 else {
4944 // failed to allocate so fallback to online cpus
4945 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4946 log_trace(os)("active_processor_count: "
4947 "CPU_ALLOC failed (%s) - using "
4948 "online processor count: %d",
4949 os::strerror(errno), online_cpus);
4950 return online_cpus;
4951 }
4952 }
4953 else {
4954 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4955 configured_cpus);
4956 }
4957 #else // CPU_ALLOC
4958 // these stubs won't be executed
4959 #define CPU_COUNT_S(size, cpus) -1
4960 #define CPU_FREE(cpus)
4961
4962 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4963 configured_cpus);
4964 #endif // CPU_ALLOC
4965
4966 // pid 0 means the current thread - which we have to assume represents the process
4967 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4968 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4969 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4970 }
4971 else {
4972 cpu_count = CPU_COUNT(cpus_p);
4973 }
4974 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
4975 }
4976 else {
4977 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
4978 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
4979 "which may exceed available processors", os::strerror(errno), cpu_count);
4980 }
4981
4982 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4983 CPU_FREE(cpus_p);
4984 }
4985
4986 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
4987 return cpu_count;
4988 }
4989
4990 void os::set_native_thread_name(const char *name) {
4991 if (Linux::_pthread_setname_np) {
4992 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
4993 snprintf(buf, sizeof(buf), "%s", name);
4994 buf[sizeof(buf) - 1] = '\0';
4995 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
4996 // ERANGE should not happen; all other errors should just be ignored.
4997 assert(rc != ERANGE, "pthread_setname_np failed");
4998 }
4999 }
5000
5001 bool os::distribute_processes(uint length, uint* distribution) {
5002 // Not yet implemented.
5003 return false;
5004 }
5005
5006 bool os::bind_to_processor(uint processor_id) {
5007 // Not yet implemented.
5008 return false;
5009 }
5010
5011 ///
5012
5013 void os::SuspendedThreadTask::internal_do_task() {
5014 if (do_suspend(_thread->osthread())) {
5015 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5016 do_task(context);
5017 do_resume(_thread->osthread());
5018 }
5019 }
5020
5021 class PcFetcher : public os::SuspendedThreadTask {
5022 public:
5023 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5024 ExtendedPC result();
5025 protected:
5026 void do_task(const os::SuspendedThreadTaskContext& context);
5027 private:
5028 ExtendedPC _epc;
5029 };
5030
5031 ExtendedPC PcFetcher::result() {
5032 guarantee(is_done(), "task is not done yet.");
5033 return _epc;
5034 }
5035
5036 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5037 Thread* thread = context.thread();
5038 OSThread* osthread = thread->osthread();
5039 if (osthread->ucontext() != NULL) {
5040 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5041 } else {
5042 // NULL context is unexpected, double-check this is the VMThread
5043 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5044 }
5045 }
5046
5047 // Suspends the target using the signal mechanism and then grabs the PC before
5048 // resuming the target. Used by the flat-profiler only
5049 ExtendedPC os::get_thread_pc(Thread* thread) {
5050 // Make sure that it is called by the watcher for the VMThread
5051 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5052 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5053
5054 PcFetcher fetcher(thread);
5055 fetcher.run();
5056 return fetcher.result();
5057 }
5058
5059 ////////////////////////////////////////////////////////////////////////////////
5060 // debug support
5061
5062 bool os::find(address addr, outputStream* st) {
5063 Dl_info dlinfo;
5064 memset(&dlinfo, 0, sizeof(dlinfo));
5065 if (dladdr(addr, &dlinfo) != 0) {
5066 st->print(PTR_FORMAT ": ", p2i(addr));
5067 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5068 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5069 p2i(addr) - p2i(dlinfo.dli_saddr));
5070 } else if (dlinfo.dli_fbase != NULL) {
5071 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5072 } else {
5073 st->print("<absolute address>");
5074 }
5075 if (dlinfo.dli_fname != NULL) {
5076 st->print(" in %s", dlinfo.dli_fname);
5077 }
5078 if (dlinfo.dli_fbase != NULL) {
5079 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5080 }
5081 st->cr();
5082
5083 if (Verbose) {
5084 // decode some bytes around the PC
5085 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5086 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5087 address lowest = (address) dlinfo.dli_sname;
5088 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5089 if (begin < lowest) begin = lowest;
5090 Dl_info dlinfo2;
5091 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5092 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5093 end = (address) dlinfo2.dli_saddr;
5094 }
5095 Disassembler::decode(begin, end, st);
5096 }
5097 return true;
5098 }
5099 return false;
5100 }
5101
5102 ////////////////////////////////////////////////////////////////////////////////
5103 // misc
5104
5105 // This does not do anything on Linux. This is basically a hook for being
5106 // able to use structured exception handling (thread-local exception filters)
5107 // on, e.g., Win32.
5108 void
5109 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5110 JavaCallArguments* args, Thread* thread) {
5111 f(value, method, args, thread);
5112 }
5113
5114 void os::print_statistics() {
5115 }
5116
5117 bool os::message_box(const char* title, const char* message) {
5118 int i;
5119 fdStream err(defaultStream::error_fd());
5120 for (i = 0; i < 78; i++) err.print_raw("=");
5121 err.cr();
5122 err.print_raw_cr(title);
5123 for (i = 0; i < 78; i++) err.print_raw("-");
5124 err.cr();
5125 err.print_raw_cr(message);
5126 for (i = 0; i < 78; i++) err.print_raw("=");
5127 err.cr();
5128
5129 char buf[16];
5130 // Prevent process from exiting upon "read error" without consuming all CPU
5131 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5132
5133 return buf[0] == 'y' || buf[0] == 'Y';
5134 }
5135
5136 int os::stat(const char *path, struct stat *sbuf) {
5137 char pathbuf[MAX_PATH];
5138 if (strlen(path) > MAX_PATH - 1) {
5139 errno = ENAMETOOLONG;
5140 return -1;
5141 }
5142 os::native_path(strcpy(pathbuf, path));
5143 return ::stat(pathbuf, sbuf);
5144 }
5145
5146 // Is a (classpath) directory empty?
5147 bool os::dir_is_empty(const char* path) {
5148 DIR *dir = NULL;
5149 struct dirent *ptr;
5150
5151 dir = opendir(path);
5152 if (dir == NULL) return true;
5153
5154 // Scan the directory
5155 bool result = true;
5156 char buf[sizeof(struct dirent) + MAX_PATH];
5157 while (result && (ptr = ::readdir(dir)) != NULL) {
5158 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5159 result = false;
5160 }
5161 }
5162 closedir(dir);
5163 return result;
5164 }
5165
5166 // This code originates from JDK's sysOpen and open64_w
5167 // from src/solaris/hpi/src/system_md.c
5168
5169 int os::open(const char *path, int oflag, int mode) {
5170 if (strlen(path) > MAX_PATH - 1) {
5171 errno = ENAMETOOLONG;
5172 return -1;
5173 }
5174
5175 // All file descriptors that are opened in the Java process and not
5176 // specifically destined for a subprocess should have the close-on-exec
5177 // flag set. If we don't set it, then careless 3rd party native code
5178 // might fork and exec without closing all appropriate file descriptors
5179 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5180 // turn might:
5181 //
5182 // - cause end-of-file to fail to be detected on some file
5183 // descriptors, resulting in mysterious hangs, or
5184 //
5185 // - might cause an fopen in the subprocess to fail on a system
5186 // suffering from bug 1085341.
5187 //
5188 // (Yes, the default setting of the close-on-exec flag is a Unix
5189 // design flaw)
5190 //
5191 // See:
5192 // 1085341: 32-bit stdio routines should support file descriptors >255
5193 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5194 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5195 //
5196 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5197 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5198 // because it saves a system call and removes a small window where the flag
5199 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5200 // and we fall back to using FD_CLOEXEC (see below).
5201 #ifdef O_CLOEXEC
5202 oflag |= O_CLOEXEC;
5203 #endif
5204
5205 int fd = ::open64(path, oflag, mode);
5206 if (fd == -1) return -1;
5207
5208 //If the open succeeded, the file might still be a directory
5209 {
5210 struct stat64 buf64;
5211 int ret = ::fstat64(fd, &buf64);
5212 int st_mode = buf64.st_mode;
5213
5214 if (ret != -1) {
5215 if ((st_mode & S_IFMT) == S_IFDIR) {
5216 errno = EISDIR;
5217 ::close(fd);
5218 return -1;
5219 }
5220 } else {
5221 ::close(fd);
5222 return -1;
5223 }
5224 }
5225
5226 #ifdef FD_CLOEXEC
5227 // Validate that the use of the O_CLOEXEC flag on open above worked.
5228 // With recent kernels, we will perform this check exactly once.
5229 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5230 if (!O_CLOEXEC_is_known_to_work) {
5231 int flags = ::fcntl(fd, F_GETFD);
5232 if (flags != -1) {
5233 if ((flags & FD_CLOEXEC) != 0)
5234 O_CLOEXEC_is_known_to_work = 1;
5235 else
5236 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5237 }
5238 }
5239 #endif
5240
5241 return fd;
5242 }
5243
5244
5245 // create binary file, rewriting existing file if required
5246 int os::create_binary_file(const char* path, bool rewrite_existing) {
5247 int oflags = O_WRONLY | O_CREAT;
5248 if (!rewrite_existing) {
5249 oflags |= O_EXCL;
5250 }
5251 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5252 }
5253
5254 // return current position of file pointer
5255 jlong os::current_file_offset(int fd) {
5256 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5257 }
5258
5259 // move file pointer to the specified offset
5260 jlong os::seek_to_file_offset(int fd, jlong offset) {
5261 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5262 }
5263
5264 // This code originates from JDK's sysAvailable
5265 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5266
5267 int os::available(int fd, jlong *bytes) {
5268 jlong cur, end;
5269 int mode;
5270 struct stat64 buf64;
5271
5272 if (::fstat64(fd, &buf64) >= 0) {
5273 mode = buf64.st_mode;
5274 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5275 int n;
5276 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5277 *bytes = n;
5278 return 1;
5279 }
5280 }
5281 }
5282 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5283 return 0;
5284 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5285 return 0;
5286 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5287 return 0;
5288 }
5289 *bytes = end - cur;
5290 return 1;
5291 }
5292
5293 // Map a block of memory.
5294 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5295 char *addr, size_t bytes, bool read_only,
5296 bool allow_exec) {
5297 int prot;
5298 int flags = MAP_PRIVATE;
5299
5300 if (read_only) {
5301 prot = PROT_READ;
5302 } else {
5303 prot = PROT_READ | PROT_WRITE;
5304 }
5305
5306 if (allow_exec) {
5307 prot |= PROT_EXEC;
5308 }
5309
5310 if (addr != NULL) {
5311 flags |= MAP_FIXED;
5312 }
5313
5314 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5315 fd, file_offset);
5316 if (mapped_address == MAP_FAILED) {
5317 return NULL;
5318 }
5319 return mapped_address;
5320 }
5321
5322
5323 // Remap a block of memory.
5324 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5325 char *addr, size_t bytes, bool read_only,
5326 bool allow_exec) {
5327 // same as map_memory() on this OS
5328 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5329 allow_exec);
5330 }
5331
5332
5333 // Unmap a block of memory.
5334 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5335 return munmap(addr, bytes) == 0;
5336 }
5337
5338 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5339
5340 static clockid_t thread_cpu_clockid(Thread* thread) {
5341 pthread_t tid = thread->osthread()->pthread_id();
5342 clockid_t clockid;
5343
5344 // Get thread clockid
5345 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5346 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5347 return clockid;
5348 }
5349
5350 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5351 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5352 // of a thread.
5353 //
5354 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5355 // the fast estimate available on the platform.
5356
5357 jlong os::current_thread_cpu_time() {
5358 if (os::Linux::supports_fast_thread_cpu_time()) {
5359 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5360 } else {
5361 // return user + sys since the cost is the same
5362 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5363 }
5364 }
5365
5366 jlong os::thread_cpu_time(Thread* thread) {
5367 // consistent with what current_thread_cpu_time() returns
5368 if (os::Linux::supports_fast_thread_cpu_time()) {
5369 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5370 } else {
5371 return slow_thread_cpu_time(thread, true /* user + sys */);
5372 }
5373 }
5374
5375 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5376 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5377 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5378 } else {
5379 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5380 }
5381 }
5382
5383 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5384 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5385 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5386 } else {
5387 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5388 }
5389 }
5390
5391 // -1 on error.
5392 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5393 pid_t tid = thread->osthread()->thread_id();
5394 char *s;
5395 char stat[2048];
5396 int statlen;
5397 char proc_name[64];
5398 int count;
5399 long sys_time, user_time;
5400 char cdummy;
5401 int idummy;
5402 long ldummy;
5403 FILE *fp;
5404
5405 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5406 fp = fopen(proc_name, "r");
5407 if (fp == NULL) return -1;
5408 statlen = fread(stat, 1, 2047, fp);
5409 stat[statlen] = '\0';
5410 fclose(fp);
5411
5412 // Skip pid and the command string. Note that we could be dealing with
5413 // weird command names, e.g. user could decide to rename java launcher
5414 // to "java 1.4.2 :)", then the stat file would look like
5415 // 1234 (java 1.4.2 :)) R ... ...
5416 // We don't really need to know the command string, just find the last
5417 // occurrence of ")" and then start parsing from there. See bug 4726580.
5418 s = strrchr(stat, ')');
5419 if (s == NULL) return -1;
5420
5421 // Skip blank chars
5422 do { s++; } while (s && isspace(*s));
5423
5424 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5425 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5426 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5427 &user_time, &sys_time);
5428 if (count != 13) return -1;
5429 if (user_sys_cpu_time) {
5430 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5431 } else {
5432 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5433 }
5434 }
5435
5436 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5437 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5438 info_ptr->may_skip_backward = false; // elapsed time not wall time
5439 info_ptr->may_skip_forward = false; // elapsed time not wall time
5440 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5441 }
5442
5443 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5444 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5445 info_ptr->may_skip_backward = false; // elapsed time not wall time
5446 info_ptr->may_skip_forward = false; // elapsed time not wall time
5447 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5448 }
5449
5450 bool os::is_thread_cpu_time_supported() {
5451 return true;
5452 }
5453
5454 // System loadavg support. Returns -1 if load average cannot be obtained.
5455 // Linux doesn't yet have a (official) notion of processor sets,
5456 // so just return the system wide load average.
5457 int os::loadavg(double loadavg[], int nelem) {
5458 return ::getloadavg(loadavg, nelem);
5459 }
5460
5461 void os::pause() {
5462 char filename[MAX_PATH];
5463 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5464 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5465 } else {
5466 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5467 }
5468
5469 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5470 if (fd != -1) {
5471 struct stat buf;
5472 ::close(fd);
5473 while (::stat(filename, &buf) == 0) {
5474 (void)::poll(NULL, 0, 100);
5475 }
5476 } else {
5477 jio_fprintf(stderr,
5478 "Could not open pause file '%s', continuing immediately.\n", filename);
5479 }
5480 }
5481
5482
5483 // Refer to the comments in os_solaris.cpp park-unpark. The next two
5484 // comment paragraphs are worth repeating here:
5485 //
5486 // Assumption:
5487 // Only one parker can exist on an event, which is why we allocate
5488 // them per-thread. Multiple unparkers can coexist.
5489 //
5490 // _Event serves as a restricted-range semaphore.
5491 // -1 : thread is blocked, i.e. there is a waiter
5492 // 0 : neutral: thread is running or ready,
5493 // could have been signaled after a wait started
5494 // 1 : signaled - thread is running or ready
5495 //
5496
5497 // utility to compute the abstime argument to timedwait:
5498 // millis is the relative timeout time
5499 // abstime will be the absolute timeout time
5500 // TODO: replace compute_abstime() with unpackTime()
5501
5502 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5503 if (millis < 0) millis = 0;
5504
5505 jlong seconds = millis / 1000;
5506 millis %= 1000;
5507 if (seconds > 50000000) { // see man cond_timedwait(3T)
5508 seconds = 50000000;
5509 }
5510
5511 if (os::supports_monotonic_clock()) {
5512 struct timespec now;
5513 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5514 assert_status(status == 0, status, "clock_gettime");
5515 abstime->tv_sec = now.tv_sec + seconds;
5516 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5517 if (nanos >= NANOSECS_PER_SEC) {
5518 abstime->tv_sec += 1;
5519 nanos -= NANOSECS_PER_SEC;
5520 }
5521 abstime->tv_nsec = nanos;
5522 } else {
5523 struct timeval now;
5524 int status = gettimeofday(&now, NULL);
5525 assert(status == 0, "gettimeofday");
5526 abstime->tv_sec = now.tv_sec + seconds;
5527 long usec = now.tv_usec + millis * 1000;
5528 if (usec >= 1000000) {
5529 abstime->tv_sec += 1;
5530 usec -= 1000000;
5531 }
5532 abstime->tv_nsec = usec * 1000;
5533 }
5534 return abstime;
5535 }
5536
5537 void os::PlatformEvent::park() { // AKA "down()"
5538 // Transitions for _Event:
5539 // -1 => -1 : illegal
5540 // 1 => 0 : pass - return immediately
5541 // 0 => -1 : block; then set _Event to 0 before returning
5542
5543 // Invariant: Only the thread associated with the Event/PlatformEvent
5544 // may call park().
5545 // TODO: assert that _Assoc != NULL or _Assoc == Self
5546 assert(_nParked == 0, "invariant");
5547
5548 int v;
5549 for (;;) {
5550 v = _Event;
5551 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5552 }
5553 guarantee(v >= 0, "invariant");
5554 if (v == 0) {
5555 // Do this the hard way by blocking ...
5556 int status = pthread_mutex_lock(_mutex);
5557 assert_status(status == 0, status, "mutex_lock");
5558 guarantee(_nParked == 0, "invariant");
5559 ++_nParked;
5560 while (_Event < 0) {
5561 status = pthread_cond_wait(_cond, _mutex);
5562 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5563 // Treat this the same as if the wait was interrupted
5564 if (status == ETIME) { status = EINTR; }
5565 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5566 }
5567 --_nParked;
5568
5569 _Event = 0;
5570 status = pthread_mutex_unlock(_mutex);
5571 assert_status(status == 0, status, "mutex_unlock");
5572 // Paranoia to ensure our locked and lock-free paths interact
5573 // correctly with each other.
5574 OrderAccess::fence();
5575 }
5576 guarantee(_Event >= 0, "invariant");
5577 }
5578
5579 int os::PlatformEvent::park(jlong millis) {
5580 // Transitions for _Event:
5581 // -1 => -1 : illegal
5582 // 1 => 0 : pass - return immediately
5583 // 0 => -1 : block; then set _Event to 0 before returning
5584
5585 guarantee(_nParked == 0, "invariant");
5586
5587 int v;
5588 for (;;) {
5589 v = _Event;
5590 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5591 }
5592 guarantee(v >= 0, "invariant");
5593 if (v != 0) return OS_OK;
5594
5595 // We do this the hard way, by blocking the thread.
5596 // Consider enforcing a minimum timeout value.
5597 struct timespec abst;
5598 compute_abstime(&abst, millis);
5599
5600 int ret = OS_TIMEOUT;
5601 int status = pthread_mutex_lock(_mutex);
5602 assert_status(status == 0, status, "mutex_lock");
5603 guarantee(_nParked == 0, "invariant");
5604 ++_nParked;
5605
5606 // Object.wait(timo) will return because of
5607 // (a) notification
5608 // (b) timeout
5609 // (c) thread.interrupt
5610 //
5611 // Thread.interrupt and object.notify{All} both call Event::set.
5612 // That is, we treat thread.interrupt as a special case of notification.
5613 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
5614 // We assume all ETIME returns are valid.
5615 //
5616 // TODO: properly differentiate simultaneous notify+interrupt.
5617 // In that case, we should propagate the notify to another waiter.
5618
5619 while (_Event < 0) {
5620 status = pthread_cond_timedwait(_cond, _mutex, &abst);
5621 assert_status(status == 0 || status == EINTR ||
5622 status == ETIME || status == ETIMEDOUT,
5623 status, "cond_timedwait");
5624 if (!FilterSpuriousWakeups) break; // previous semantics
5625 if (status == ETIME || status == ETIMEDOUT) break;
5626 // We consume and ignore EINTR and spurious wakeups.
5627 }
5628 --_nParked;
5629 if (_Event >= 0) {
5630 ret = OS_OK;
5631 }
5632 _Event = 0;
5633 status = pthread_mutex_unlock(_mutex);
5634 assert_status(status == 0, status, "mutex_unlock");
5635 assert(_nParked == 0, "invariant");
5636 // Paranoia to ensure our locked and lock-free paths interact
5637 // correctly with each other.
5638 OrderAccess::fence();
5639 return ret;
5640 }
5641
5642 void os::PlatformEvent::unpark() {
5643 // Transitions for _Event:
5644 // 0 => 1 : just return
5645 // 1 => 1 : just return
5646 // -1 => either 0 or 1; must signal target thread
5647 // That is, we can safely transition _Event from -1 to either
5648 // 0 or 1.
5649 // See also: "Semaphores in Plan 9" by Mullender & Cox
5650 //
5651 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5652 // that it will take two back-to-back park() calls for the owning
5653 // thread to block. This has the benefit of forcing a spurious return
5654 // from the first park() call after an unpark() call which will help
5655 // shake out uses of park() and unpark() without condition variables.
5656
5657 if (Atomic::xchg(1, &_Event) >= 0) return;
5658
5659 // Wait for the thread associated with the event to vacate
5660 int status = pthread_mutex_lock(_mutex);
5661 assert_status(status == 0, status, "mutex_lock");
5662 int AnyWaiters = _nParked;
5663 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5664 status = pthread_mutex_unlock(_mutex);
5665 assert_status(status == 0, status, "mutex_unlock");
5666 if (AnyWaiters != 0) {
5667 // Note that we signal() *after* dropping the lock for "immortal" Events.
5668 // This is safe and avoids a common class of futile wakeups. In rare
5669 // circumstances this can cause a thread to return prematurely from
5670 // cond_{timed}wait() but the spurious wakeup is benign and the victim
5671 // will simply re-test the condition and re-park itself.
5672 // This provides particular benefit if the underlying platform does not
5673 // provide wait morphing.
5674 status = pthread_cond_signal(_cond);
5675 assert_status(status == 0, status, "cond_signal");
5676 }
5677 }
5678
5679
5680 // JSR166
5681 // -------------------------------------------------------
5682
5683 // The solaris and linux implementations of park/unpark are fairly
5684 // conservative for now, but can be improved. They currently use a
5685 // mutex/condvar pair, plus a a count.
5686 // Park decrements count if > 0, else does a condvar wait. Unpark
5687 // sets count to 1 and signals condvar. Only one thread ever waits
5688 // on the condvar. Contention seen when trying to park implies that someone
5689 // is unparking you, so don't wait. And spurious returns are fine, so there
5690 // is no need to track notifications.
5691
5692 // This code is common to linux and solaris and will be moved to a
5693 // common place in dolphin.
5694 //
5695 // The passed in time value is either a relative time in nanoseconds
5696 // or an absolute time in milliseconds. Either way it has to be unpacked
5697 // into suitable seconds and nanoseconds components and stored in the
5698 // given timespec structure.
5699 // Given time is a 64-bit value and the time_t used in the timespec is only
5700 // a signed-32-bit value (except on 64-bit Linux) we have to watch for
5701 // overflow if times way in the future are given. Further on Solaris versions
5702 // prior to 10 there is a restriction (see cond_timedwait) that the specified
5703 // number of seconds, in abstime, is less than current_time + 100,000,000.
5704 // As it will be 28 years before "now + 100000000" will overflow we can
5705 // ignore overflow and just impose a hard-limit on seconds using the value
5706 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
5707 // years from "now".
5708
5709 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5710 assert(time > 0, "convertTime");
5711 time_t max_secs = 0;
5712
5713 if (!os::supports_monotonic_clock() || isAbsolute) {
5714 struct timeval now;
5715 int status = gettimeofday(&now, NULL);
5716 assert(status == 0, "gettimeofday");
5717
5718 max_secs = now.tv_sec + MAX_SECS;
5719
5720 if (isAbsolute) {
5721 jlong secs = time / 1000;
5722 if (secs > max_secs) {
5723 absTime->tv_sec = max_secs;
5724 } else {
5725 absTime->tv_sec = secs;
5726 }
5727 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5728 } else {
5729 jlong secs = time / NANOSECS_PER_SEC;
5730 if (secs >= MAX_SECS) {
5731 absTime->tv_sec = max_secs;
5732 absTime->tv_nsec = 0;
5733 } else {
5734 absTime->tv_sec = now.tv_sec + secs;
5735 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5736 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5737 absTime->tv_nsec -= NANOSECS_PER_SEC;
5738 ++absTime->tv_sec; // note: this must be <= max_secs
5739 }
5740 }
5741 }
5742 } else {
5743 // must be relative using monotonic clock
5744 struct timespec now;
5745 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5746 assert_status(status == 0, status, "clock_gettime");
5747 max_secs = now.tv_sec + MAX_SECS;
5748 jlong secs = time / NANOSECS_PER_SEC;
5749 if (secs >= MAX_SECS) {
5750 absTime->tv_sec = max_secs;
5751 absTime->tv_nsec = 0;
5752 } else {
5753 absTime->tv_sec = now.tv_sec + secs;
5754 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5755 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5756 absTime->tv_nsec -= NANOSECS_PER_SEC;
5757 ++absTime->tv_sec; // note: this must be <= max_secs
5758 }
5759 }
5760 }
5761 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5762 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5763 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5764 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5765 }
5766
5767 void Parker::park(bool isAbsolute, jlong time) {
5768 // Ideally we'd do something useful while spinning, such
5769 // as calling unpackTime().
5770
5771 // Optional fast-path check:
5772 // Return immediately if a permit is available.
5773 // We depend on Atomic::xchg() having full barrier semantics
5774 // since we are doing a lock-free update to _counter.
5775 if (Atomic::xchg(0, &_counter) > 0) return;
5776
5777 Thread* thread = Thread::current();
5778 assert(thread->is_Java_thread(), "Must be JavaThread");
5779 JavaThread *jt = (JavaThread *)thread;
5780
5781 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5782 // Check interrupt before trying to wait
5783 if (Thread::is_interrupted(thread, false)) {
5784 return;
5785 }
5786
5787 // Next, demultiplex/decode time arguments
5788 timespec absTime;
5789 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
5790 return;
5791 }
5792 if (time > 0) {
5793 unpackTime(&absTime, isAbsolute, time);
5794 }
5795
5796
5797 // Enter safepoint region
5798 // Beware of deadlocks such as 6317397.
5799 // The per-thread Parker:: mutex is a classic leaf-lock.
5800 // In particular a thread must never block on the Threads_lock while
5801 // holding the Parker:: mutex. If safepoints are pending both the
5802 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5803 ThreadBlockInVM tbivm(jt);
5804
5805 // Don't wait if cannot get lock since interference arises from
5806 // unblocking. Also. check interrupt before trying wait
5807 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5808 return;
5809 }
5810
5811 int status;
5812 if (_counter > 0) { // no wait needed
5813 _counter = 0;
5814 status = pthread_mutex_unlock(_mutex);
5815 assert_status(status == 0, status, "invariant");
5816 // Paranoia to ensure our locked and lock-free paths interact
5817 // correctly with each other and Java-level accesses.
5818 OrderAccess::fence();
5819 return;
5820 }
5821
5822 #ifdef ASSERT
5823 // Don't catch signals while blocked; let the running threads have the signals.
5824 // (This allows a debugger to break into the running thread.)
5825 sigset_t oldsigs;
5826 sigemptyset(&oldsigs);
5827 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5828 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5829 #endif
5830
5831 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5832 jt->set_suspend_equivalent();
5833 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5834
5835 assert(_cur_index == -1, "invariant");
5836 if (time == 0) {
5837 _cur_index = REL_INDEX; // arbitrary choice when not timed
5838 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
5839 } else {
5840 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5841 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
5842 }
5843 _cur_index = -1;
5844 assert_status(status == 0 || status == EINTR ||
5845 status == ETIME || status == ETIMEDOUT,
5846 status, "cond_timedwait");
5847
5848 #ifdef ASSERT
5849 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5850 #endif
5851
5852 _counter = 0;
5853 status = pthread_mutex_unlock(_mutex);
5854 assert_status(status == 0, status, "invariant");
5855 // Paranoia to ensure our locked and lock-free paths interact
5856 // correctly with each other and Java-level accesses.
5857 OrderAccess::fence();
5858
5859 // If externally suspended while waiting, re-suspend
5860 if (jt->handle_special_suspend_equivalent_condition()) {
5861 jt->java_suspend_self();
5862 }
5863 }
5864
5865 void Parker::unpark() {
5866 int status = pthread_mutex_lock(_mutex);
5867 assert_status(status == 0, status, "invariant");
5868 const int s = _counter;
5869 _counter = 1;
5870 // must capture correct index before unlocking
5871 int index = _cur_index;
5872 status = pthread_mutex_unlock(_mutex);
5873 assert_status(status == 0, status, "invariant");
5874 if (s < 1 && index != -1) {
5875 // thread is definitely parked
5876 status = pthread_cond_signal(&_cond[index]);
5877 assert_status(status == 0, status, "invariant");
5878 }
5879 }
5880
5881
5882 extern char** environ;
5883
5884 // Run the specified command in a separate process. Return its exit value,
5885 // or -1 on failure (e.g. can't fork a new process).
5886 // Unlike system(), this function can be called from signal handler. It
5887 // doesn't block SIGINT et al.
5888 int os::fork_and_exec(char* cmd) {
5889 const char * argv[4] = {"sh", "-c", cmd, NULL};
5890
5891 pid_t pid = fork();
5892
5893 if (pid < 0) {
5894 // fork failed
5895 return -1;
5896
5897 } else if (pid == 0) {
5898 // child process
5899
5900 execve("/bin/sh", (char* const*)argv, environ);
5901
5902 // execve failed
5903 _exit(-1);
5904
5905 } else {
5906 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5907 // care about the actual exit code, for now.
5908
5909 int status;
5910
5911 // Wait for the child process to exit. This returns immediately if
5912 // the child has already exited. */
5913 while (waitpid(pid, &status, 0) < 0) {
5914 switch (errno) {
5915 case ECHILD: return 0;
5916 case EINTR: break;
5917 default: return -1;
5918 }
5919 }
5920
5921 if (WIFEXITED(status)) {
5922 // The child exited normally; get its exit code.
5923 return WEXITSTATUS(status);
5924 } else if (WIFSIGNALED(status)) {
5925 // The child exited because of a signal
5926 // The best value to return is 0x80 + signal number,
5927 // because that is what all Unix shells do, and because
5928 // it allows callers to distinguish between process exit and
5929 // process death by signal.
5930 return 0x80 + WTERMSIG(status);
5931 } else {
5932 // Unknown exit code; pass it through
5933 return status;
5934 }
5935 }
5936 }
5937
5938 // is_headless_jre()
5939 //
5940 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5941 // in order to report if we are running in a headless jre
5942 //
5943 // Since JDK8 xawt/libmawt.so was moved into the same directory
5944 // as libawt.so, and renamed libawt_xawt.so
5945 //
5946 bool os::is_headless_jre() {
5947 struct stat statbuf;
5948 char buf[MAXPATHLEN];
5949 char libmawtpath[MAXPATHLEN];
5950 const char *xawtstr = "/xawt/libmawt.so";
5951 const char *new_xawtstr = "/libawt_xawt.so";
5952 char *p;
5953
5954 // Get path to libjvm.so
5955 os::jvm_path(buf, sizeof(buf));
5956
5957 // Get rid of libjvm.so
5958 p = strrchr(buf, '/');
5959 if (p == NULL) {
5960 return false;
5961 } else {
5962 *p = '\0';
5963 }
5964
5965 // Get rid of client or server
5966 p = strrchr(buf, '/');
5967 if (p == NULL) {
5968 return false;
5969 } else {
5970 *p = '\0';
5971 }
5972
5973 // check xawt/libmawt.so
5974 strcpy(libmawtpath, buf);
5975 strcat(libmawtpath, xawtstr);
5976 if (::stat(libmawtpath, &statbuf) == 0) return false;
5977
5978 // check libawt_xawt.so
5979 strcpy(libmawtpath, buf);
5980 strcat(libmawtpath, new_xawtstr);
5981 if (::stat(libmawtpath, &statbuf) == 0) return false;
5982
5983 return true;
5984 }
5985
5986 // Get the default path to the core file
5987 // Returns the length of the string
5988 int os::get_core_path(char* buffer, size_t bufferSize) {
5989 /*
5990 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5991 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5992 */
5993 const int core_pattern_len = 129;
5994 char core_pattern[core_pattern_len] = {0};
5995
5996 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5997 if (core_pattern_file == -1) {
5998 return -1;
5999 }
6000
6001 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
6002 ::close(core_pattern_file);
6003 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
6004 return -1;
6005 }
6006 if (core_pattern[ret-1] == '\n') {
6007 core_pattern[ret-1] = '\0';
6008 } else {
6009 core_pattern[ret] = '\0';
6010 }
6011
6012 char *pid_pos = strstr(core_pattern, "%p");
6013 int written;
6014
6015 if (core_pattern[0] == '/') {
6016 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6017 } else {
6018 char cwd[PATH_MAX];
6019
6020 const char* p = get_current_directory(cwd, PATH_MAX);
6021 if (p == NULL) {
6022 return -1;
6023 }
6024
6025 if (core_pattern[0] == '|') {
6026 written = jio_snprintf(buffer, bufferSize,
6027 "\"%s\" (or dumping to %s/core.%d)",
6028 &core_pattern[1], p, current_process_id());
6029 } else {
6030 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6031 }
6032 }
6033
6034 if (written < 0) {
6035 return -1;
6036 }
6037
6038 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6039 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6040
6041 if (core_uses_pid_file != -1) {
6042 char core_uses_pid = 0;
6043 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6044 ::close(core_uses_pid_file);
6045
6046 if (core_uses_pid == '1') {
6047 jio_snprintf(buffer + written, bufferSize - written,
6048 ".%d", current_process_id());
6049 }
6050 }
6051 }
6052
6053 return strlen(buffer);
6054 }
6055
6056 bool os::start_debugging(char *buf, int buflen) {
6057 int len = (int)strlen(buf);
6058 char *p = &buf[len];
6059
6060 jio_snprintf(p, buflen-len,
6061 "\n\n"
6062 "Do you want to debug the problem?\n\n"
6063 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6064 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6065 "Otherwise, press RETURN to abort...",
6066 os::current_process_id(), os::current_process_id(),
6067 os::current_thread_id(), os::current_thread_id());
6068
6069 bool yes = os::message_box("Unexpected Error", buf);
6070
6071 if (yes) {
6072 // yes, user asked VM to launch debugger
6073 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6074 os::current_process_id(), os::current_process_id());
6075
6076 os::fork_and_exec(buf);
6077 yes = false;
6078 }
6079 return yes;
6080 }
6081
6082
6083 // Java/Compiler thread:
6084 //
6085 // Low memory addresses
6086 // P0 +------------------------+
6087 // | |\ Java thread created by VM does not have glibc
6088 // | glibc guard page | - guard page, attached Java thread usually has
6089 // | |/ 1 glibc guard page.
6090 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6091 // | |\
6092 // | HotSpot Guard Pages | - red, yellow and reserved pages
6093 // | |/
6094 // +------------------------+ JavaThread::stack_reserved_zone_base()
6095 // | |\
6096 // | Normal Stack | -
6097 // | |/
6098 // P2 +------------------------+ Thread::stack_base()
6099 //
6100 // Non-Java thread:
6101 //
6102 // Low memory addresses
6103 // P0 +------------------------+
6104 // | |\
6105 // | glibc guard page | - usually 1 page
6106 // | |/
6107 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
6108 // | |\
6109 // | Normal Stack | -
6110 // | |/
6111 // P2 +------------------------+ Thread::stack_base()
6112 //
6113 // ** P1 (aka bottom) and size (P2 = P1 - size) are the address and stack size
6114 // returned from pthread_attr_getstack().
6115 // ** Due to NPTL implementation error, linux takes the glibc guard page out
6116 // of the stack size given in pthread_attr. We work around this for
6117 // threads created by the VM. (We adapt bottom to be P1 and size accordingly.)
6118 //
6119 #ifndef ZERO
6120 static void current_stack_region(address * bottom, size_t * size) {
6121 if (os::Linux::is_initial_thread()) {
6122 // initial thread needs special handling because pthread_getattr_np()
6123 // may return bogus value.
6124 *bottom = os::Linux::initial_thread_stack_bottom();
6125 *size = os::Linux::initial_thread_stack_size();
6126 } else {
6127 pthread_attr_t attr;
6128
6129 int rslt = pthread_getattr_np(pthread_self(), &attr);
6130
6131 // JVM needs to know exact stack location, abort if it fails
6132 if (rslt != 0) {
6133 if (rslt == ENOMEM) {
6134 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
6135 } else {
6136 fatal("pthread_getattr_np failed with error = %d", rslt);
6137 }
6138 }
6139
6140 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
6141 fatal("Cannot locate current stack attributes!");
6142 }
6143
6144 // Work around NPTL stack guard error.
6145 size_t guard_size = 0;
6146 rslt = pthread_attr_getguardsize(&attr, &guard_size);
6147 if (rslt != 0) {
6148 fatal("pthread_attr_getguardsize failed with error = %d", rslt);
6149 }
6150 *bottom += guard_size;
6151 *size -= guard_size;
6152
6153 pthread_attr_destroy(&attr);
6154
6155 }
6156 assert(os::current_stack_pointer() >= *bottom &&
6157 os::current_stack_pointer() < *bottom + *size, "just checking");
6158 }
6159
6160 address os::current_stack_base() {
6161 address bottom;
6162 size_t size;
6163 current_stack_region(&bottom, &size);
6164 return (bottom + size);
6165 }
6166
6167 size_t os::current_stack_size() {
6168 // This stack size includes the usable stack and HotSpot guard pages
6169 // (for the threads that have Hotspot guard pages).
6170 address bottom;
6171 size_t size;
6172 current_stack_region(&bottom, &size);
6173 return size;
6174 }
6175 #endif
6176
6177 static inline struct timespec get_mtime(const char* filename) {
6178 struct stat st;
6179 int ret = os::stat(filename, &st);
6180 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
6181 return st.st_mtim;
6182 }
6183
6184 int os::compare_file_modified_times(const char* file1, const char* file2) {
6185 struct timespec filetime1 = get_mtime(file1);
6186 struct timespec filetime2 = get_mtime(file2);
6187 int diff = filetime1.tv_sec - filetime2.tv_sec;
6188 if (diff == 0) {
6189 return filetime1.tv_nsec - filetime2.tv_nsec;
6190 }
6191 return diff;
6192 }
6193
6194 /////////////// Unit tests ///////////////
6195
6196 #ifndef PRODUCT
6197
6198 #define test_log(...) \
6199 do { \
6200 if (VerboseInternalVMTests) { \
6201 tty->print_cr(__VA_ARGS__); \
6202 tty->flush(); \
6203 } \
6204 } while (false)
6205
6206 class TestReserveMemorySpecial : AllStatic {
6207 public:
6208 static void small_page_write(void* addr, size_t size) {
6209 size_t page_size = os::vm_page_size();
6210
6211 char* end = (char*)addr + size;
6212 for (char* p = (char*)addr; p < end; p += page_size) {
6213 *p = 1;
6214 }
6215 }
6216
6217 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6218 if (!UseHugeTLBFS) {
6219 return;
6220 }
6221
6222 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6223
6224 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6225
6226 if (addr != NULL) {
6227 small_page_write(addr, size);
6228
6229 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6230 }
6231 }
6232
6233 static void test_reserve_memory_special_huge_tlbfs_only() {
6234 if (!UseHugeTLBFS) {
6235 return;
6236 }
6237
6238 size_t lp = os::large_page_size();
6239
6240 for (size_t size = lp; size <= lp * 10; size += lp) {
6241 test_reserve_memory_special_huge_tlbfs_only(size);
6242 }
6243 }
6244
6245 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6246 size_t lp = os::large_page_size();
6247 size_t ag = os::vm_allocation_granularity();
6248
6249 // sizes to test
6250 const size_t sizes[] = {
6251 lp, lp + ag, lp + lp / 2, lp * 2,
6252 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6253 lp * 10, lp * 10 + lp / 2
6254 };
6255 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6256
6257 // For each size/alignment combination, we test three scenarios:
6258 // 1) with req_addr == NULL
6259 // 2) with a non-null req_addr at which we expect to successfully allocate
6260 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6261 // expect the allocation to either fail or to ignore req_addr
6262
6263 // Pre-allocate two areas; they shall be as large as the largest allocation
6264 // and aligned to the largest alignment we will be testing.
6265 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6266 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6267 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6268 -1, 0);
6269 assert(mapping1 != MAP_FAILED, "should work");
6270
6271 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6272 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6273 -1, 0);
6274 assert(mapping2 != MAP_FAILED, "should work");
6275
6276 // Unmap the first mapping, but leave the second mapping intact: the first
6277 // mapping will serve as a value for a "good" req_addr (case 2). The second
6278 // mapping, still intact, as "bad" req_addr (case 3).
6279 ::munmap(mapping1, mapping_size);
6280
6281 // Case 1
6282 test_log("%s, req_addr NULL:", __FUNCTION__);
6283 test_log("size align result");
6284
6285 for (int i = 0; i < num_sizes; i++) {
6286 const size_t size = sizes[i];
6287 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6288 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6289 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6290 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6291 if (p != NULL) {
6292 assert(is_ptr_aligned(p, alignment), "must be");
6293 small_page_write(p, size);
6294 os::Linux::release_memory_special_huge_tlbfs(p, size);
6295 }
6296 }
6297 }
6298
6299 // Case 2
6300 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6301 test_log("size align req_addr result");
6302
6303 for (int i = 0; i < num_sizes; i++) {
6304 const size_t size = sizes[i];
6305 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6306 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6307 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6308 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6309 size, alignment, p2i(req_addr), p2i(p),
6310 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6311 if (p != NULL) {
6312 assert(p == req_addr, "must be");
6313 small_page_write(p, size);
6314 os::Linux::release_memory_special_huge_tlbfs(p, size);
6315 }
6316 }
6317 }
6318
6319 // Case 3
6320 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6321 test_log("size align req_addr result");
6322
6323 for (int i = 0; i < num_sizes; i++) {
6324 const size_t size = sizes[i];
6325 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6326 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6327 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6328 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6329 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6330 // as the area around req_addr contains already existing mappings, the API should always
6331 // return NULL (as per contract, it cannot return another address)
6332 assert(p == NULL, "must be");
6333 }
6334 }
6335
6336 ::munmap(mapping2, mapping_size);
6337
6338 }
6339
6340 static void test_reserve_memory_special_huge_tlbfs() {
6341 if (!UseHugeTLBFS) {
6342 return;
6343 }
6344
6345 test_reserve_memory_special_huge_tlbfs_only();
6346 test_reserve_memory_special_huge_tlbfs_mixed();
6347 }
6348
6349 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6350 if (!UseSHM) {
6351 return;
6352 }
6353
6354 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6355
6356 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6357
6358 if (addr != NULL) {
6359 assert(is_ptr_aligned(addr, alignment), "Check");
6360 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6361
6362 small_page_write(addr, size);
6363
6364 os::Linux::release_memory_special_shm(addr, size);
6365 }
6366 }
6367
6368 static void test_reserve_memory_special_shm() {
6369 size_t lp = os::large_page_size();
6370 size_t ag = os::vm_allocation_granularity();
6371
6372 for (size_t size = ag; size < lp * 3; size += ag) {
6373 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6374 test_reserve_memory_special_shm(size, alignment);
6375 }
6376 }
6377 }
6378
6379 static void test() {
6380 test_reserve_memory_special_huge_tlbfs();
6381 test_reserve_memory_special_shm();
6382 }
6383 };
6384
6385 void TestReserveMemorySpecial_test() {
6386 TestReserveMemorySpecial::test();
6387 }
6388
6389 #endif