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.inline.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 // Cpu architecture string
222 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
223
224
225 // pid_t gettid()
226 //
227 // Returns the kernel thread id of the currently running thread. Kernel
228 // thread id is used to access /proc.
229 pid_t os::Linux::gettid() {
230 int rslt = syscall(SYS_gettid);
231 assert(rslt != -1, "must be."); // old linuxthreads implementation?
232 return (pid_t)rslt;
233 }
234
235 // Most versions of linux have a bug where the number of processors are
236 // determined by looking at the /proc file system. In a chroot environment,
237 // the system call returns 1. This causes the VM to act as if it is
238 // a single processor and elide locking (see is_MP() call).
239 static bool unsafe_chroot_detected = false;
240 static const char *unstable_chroot_error = "/proc file system not found.\n"
241 "Java may be unstable running multithreaded in a chroot "
242 "environment on Linux when /proc filesystem is not mounted.";
243
244 void os::Linux::initialize_system_info() {
245 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
246 if (processor_count() == 1) {
247 pid_t pid = os::Linux::gettid();
248 char fname[32];
249 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
250 FILE *fp = fopen(fname, "r");
251 if (fp == NULL) {
252 unsafe_chroot_detected = true;
253 } else {
254 fclose(fp);
255 }
256 }
257 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
258 assert(processor_count() > 0, "linux error");
259 }
260
261 void os::init_system_properties_values() {
262 // The next steps are taken in the product version:
263 //
264 // Obtain the JAVA_HOME value from the location of libjvm.so.
265 // This library should be located at:
266 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
267 //
268 // If "/jre/lib/" appears at the right place in the path, then we
269 // assume libjvm.so is installed in a JDK and we use this path.
270 //
271 // Otherwise exit with message: "Could not create the Java virtual machine."
272 //
273 // The following extra steps are taken in the debugging version:
274 //
275 // If "/jre/lib/" does NOT appear at the right place in the path
276 // instead of exit check for $JAVA_HOME environment variable.
277 //
278 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
279 // then we append a fake suffix "hotspot/libjvm.so" to this path so
280 // it looks like libjvm.so is installed there
281 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
282 //
283 // Otherwise exit.
284 //
285 // Important note: if the location of libjvm.so changes this
286 // code needs to be changed accordingly.
287
288 // See ld(1):
289 // The linker uses the following search paths to locate required
290 // shared libraries:
291 // 1: ...
292 // ...
293 // 7: The default directories, normally /lib and /usr/lib.
294 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
295 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
296 #else
297 #define DEFAULT_LIBPATH "/lib:/usr/lib"
298 #endif
299
300 // Base path of extensions installed on the system.
301 #define SYS_EXT_DIR "/usr/java/packages"
302 #define EXTENSIONS_DIR "/lib/ext"
303
304 // Buffer that fits several sprintfs.
305 // Note that the space for the colon and the trailing null are provided
306 // by the nulls included by the sizeof operator.
307 const size_t bufsize =
308 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
309 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
310 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
311
312 // sysclasspath, java_home, dll_dir
313 {
314 char *pslash;
315 os::jvm_path(buf, bufsize);
316
317 // Found the full path to libjvm.so.
318 // Now cut the path to <java_home>/jre if we can.
319 pslash = strrchr(buf, '/');
320 if (pslash != NULL) {
321 *pslash = '\0'; // Get rid of /libjvm.so.
322 }
323 pslash = strrchr(buf, '/');
324 if (pslash != NULL) {
325 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
326 }
327 Arguments::set_dll_dir(buf);
328
329 if (pslash != NULL) {
330 pslash = strrchr(buf, '/');
331 if (pslash != NULL) {
332 *pslash = '\0'; // Get rid of /<arch>.
333 pslash = strrchr(buf, '/');
334 if (pslash != NULL) {
335 *pslash = '\0'; // Get rid of /lib.
336 }
337 }
338 }
339 Arguments::set_java_home(buf);
340 set_boot_path('/', ':');
341 }
342
343 // Where to look for native libraries.
344 //
345 // Note: Due to a legacy implementation, most of the library path
346 // is set in the launcher. This was to accomodate linking restrictions
347 // on legacy Linux implementations (which are no longer supported).
348 // Eventually, all the library path setting will be done here.
349 //
350 // However, to prevent the proliferation of improperly built native
351 // libraries, the new path component /usr/java/packages is added here.
352 // Eventually, all the library path setting will be done here.
353 {
354 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
355 // should always exist (until the legacy problem cited above is
356 // addressed).
357 const char *v = ::getenv("LD_LIBRARY_PATH");
358 const char *v_colon = ":";
359 if (v == NULL) { v = ""; v_colon = ""; }
360 // That's +1 for the colon and +1 for the trailing '\0'.
361 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
362 strlen(v) + 1 +
363 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
364 mtInternal);
365 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
366 Arguments::set_library_path(ld_library_path);
367 FREE_C_HEAP_ARRAY(char, ld_library_path);
368 }
369
370 // Extensions directories.
371 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
372 Arguments::set_ext_dirs(buf);
373
374 FREE_C_HEAP_ARRAY(char, buf);
375
376 #undef DEFAULT_LIBPATH
377 #undef SYS_EXT_DIR
378 #undef EXTENSIONS_DIR
379 }
380
381 ////////////////////////////////////////////////////////////////////////////////
382 // breakpoint support
383
384 void os::breakpoint() {
385 BREAKPOINT;
386 }
387
388 extern "C" void breakpoint() {
389 // use debugger to set breakpoint here
390 }
391
392 ////////////////////////////////////////////////////////////////////////////////
393 // signal support
394
395 debug_only(static bool signal_sets_initialized = false);
396 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
397
398 bool os::Linux::is_sig_ignored(int sig) {
399 struct sigaction oact;
400 sigaction(sig, (struct sigaction*)NULL, &oact);
401 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
402 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
403 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
404 return true;
405 } else {
406 return false;
407 }
408 }
409
410 void os::Linux::signal_sets_init() {
411 // Should also have an assertion stating we are still single-threaded.
412 assert(!signal_sets_initialized, "Already initialized");
413 // Fill in signals that are necessarily unblocked for all threads in
414 // the VM. Currently, we unblock the following signals:
415 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
416 // by -Xrs (=ReduceSignalUsage));
417 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
418 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
419 // the dispositions or masks wrt these signals.
420 // Programs embedding the VM that want to use the above signals for their
421 // own purposes must, at this time, use the "-Xrs" option to prevent
422 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
423 // (See bug 4345157, and other related bugs).
424 // In reality, though, unblocking these signals is really a nop, since
425 // these signals are not blocked by default.
426 sigemptyset(&unblocked_sigs);
427 sigemptyset(&allowdebug_blocked_sigs);
428 sigaddset(&unblocked_sigs, SIGILL);
429 sigaddset(&unblocked_sigs, SIGSEGV);
430 sigaddset(&unblocked_sigs, SIGBUS);
431 sigaddset(&unblocked_sigs, SIGFPE);
432 #if defined(PPC64)
433 sigaddset(&unblocked_sigs, SIGTRAP);
434 #endif
435 sigaddset(&unblocked_sigs, SR_signum);
436
437 if (!ReduceSignalUsage) {
438 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
439 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
440 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
441 }
442 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
443 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
444 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
445 }
446 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
447 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
448 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
449 }
450 }
451 // Fill in signals that are blocked by all but the VM thread.
452 sigemptyset(&vm_sigs);
453 if (!ReduceSignalUsage) {
454 sigaddset(&vm_sigs, BREAK_SIGNAL);
455 }
456 debug_only(signal_sets_initialized = true);
457
458 }
459
460 // These are signals that are unblocked while a thread is running Java.
461 // (For some reason, they get blocked by default.)
462 sigset_t* os::Linux::unblocked_signals() {
463 assert(signal_sets_initialized, "Not initialized");
464 return &unblocked_sigs;
465 }
466
467 // These are the signals that are blocked while a (non-VM) thread is
468 // running Java. Only the VM thread handles these signals.
469 sigset_t* os::Linux::vm_signals() {
470 assert(signal_sets_initialized, "Not initialized");
471 return &vm_sigs;
472 }
473
474 // These are signals that are blocked during cond_wait to allow debugger in
475 sigset_t* os::Linux::allowdebug_blocked_signals() {
476 assert(signal_sets_initialized, "Not initialized");
477 return &allowdebug_blocked_sigs;
478 }
479
480 void os::Linux::hotspot_sigmask(Thread* thread) {
481
482 //Save caller's signal mask before setting VM signal mask
483 sigset_t caller_sigmask;
484 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
485
486 OSThread* osthread = thread->osthread();
487 osthread->set_caller_sigmask(caller_sigmask);
488
489 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
490
491 if (!ReduceSignalUsage) {
492 if (thread->is_VM_thread()) {
493 // Only the VM thread handles BREAK_SIGNAL ...
494 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
495 } else {
496 // ... all other threads block BREAK_SIGNAL
497 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
498 }
499 }
500 }
501
502 //////////////////////////////////////////////////////////////////////////////
503 // detecting pthread library
504
505 void os::Linux::libpthread_init() {
506 // Save glibc and pthread version strings.
507 #if !defined(_CS_GNU_LIBC_VERSION) || \
508 !defined(_CS_GNU_LIBPTHREAD_VERSION)
509 #error "glibc too old (< 2.3.2)"
510 #endif
511
512 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
513 assert(n > 0, "cannot retrieve glibc version");
514 char *str = (char *)malloc(n, mtInternal);
515 confstr(_CS_GNU_LIBC_VERSION, str, n);
516 os::Linux::set_glibc_version(str);
517
518 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
519 assert(n > 0, "cannot retrieve pthread version");
520 str = (char *)malloc(n, mtInternal);
521 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
522 os::Linux::set_libpthread_version(str);
523 }
524
525 /////////////////////////////////////////////////////////////////////////////
526 // thread stack expansion
527
528 // os::Linux::manually_expand_stack() takes care of expanding the thread
529 // stack. Note that this is normally not needed: pthread stacks allocate
530 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
531 // committed. Therefore it is not necessary to expand the stack manually.
532 //
533 // Manually expanding the stack was historically needed on LinuxThreads
534 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
535 // it is kept to deal with very rare corner cases:
536 //
537 // For one, user may run the VM on an own implementation of threads
538 // whose stacks are - like the old LinuxThreads - implemented using
539 // mmap(MAP_GROWSDOWN).
540 //
541 // Also, this coding may be needed if the VM is running on the primordial
542 // thread. Normally we avoid running on the primordial thread; however,
543 // user may still invoke the VM on the primordial thread.
544 //
545 // The following historical comment describes the details about running
546 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
547
548
549 // Force Linux kernel to expand current thread stack. If "bottom" is close
550 // to the stack guard, caller should block all signals.
551 //
552 // MAP_GROWSDOWN:
553 // A special mmap() flag that is used to implement thread stacks. It tells
554 // kernel that the memory region should extend downwards when needed. This
555 // allows early versions of LinuxThreads to only mmap the first few pages
556 // when creating a new thread. Linux kernel will automatically expand thread
557 // stack as needed (on page faults).
558 //
559 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
560 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
561 // region, it's hard to tell if the fault is due to a legitimate stack
562 // access or because of reading/writing non-exist memory (e.g. buffer
563 // overrun). As a rule, if the fault happens below current stack pointer,
564 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
565 // application (see Linux kernel fault.c).
566 //
567 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
568 // stack overflow detection.
569 //
570 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
571 // not use MAP_GROWSDOWN.
572 //
573 // To get around the problem and allow stack banging on Linux, we need to
574 // manually expand thread stack after receiving the SIGSEGV.
575 //
576 // There are two ways to expand thread stack to address "bottom", we used
577 // both of them in JVM before 1.5:
578 // 1. adjust stack pointer first so that it is below "bottom", and then
579 // touch "bottom"
580 // 2. mmap() the page in question
581 //
582 // Now alternate signal stack is gone, it's harder to use 2. For instance,
583 // if current sp is already near the lower end of page 101, and we need to
584 // call mmap() to map page 100, it is possible that part of the mmap() frame
585 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
586 // That will destroy the mmap() frame and cause VM to crash.
587 //
588 // The following code works by adjusting sp first, then accessing the "bottom"
589 // page to force a page fault. Linux kernel will then automatically expand the
590 // stack mapping.
591 //
592 // _expand_stack_to() assumes its frame size is less than page size, which
593 // should always be true if the function is not inlined.
594
595 static void NOINLINE _expand_stack_to(address bottom) {
596 address sp;
597 size_t size;
598 volatile char *p;
599
600 // Adjust bottom to point to the largest address within the same page, it
601 // gives us a one-page buffer if alloca() allocates slightly more memory.
602 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
603 bottom += os::Linux::page_size() - 1;
604
605 // sp might be slightly above current stack pointer; if that's the case, we
606 // will alloca() a little more space than necessary, which is OK. Don't use
607 // os::current_stack_pointer(), as its result can be slightly below current
608 // stack pointer, causing us to not alloca enough to reach "bottom".
609 sp = (address)&sp;
610
611 if (sp > bottom) {
612 size = sp - bottom;
613 p = (volatile char *)alloca(size);
614 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
615 p[0] = '\0';
616 }
617 }
618
619 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
620 assert(t!=NULL, "just checking");
621 assert(t->osthread()->expanding_stack(), "expand should be set");
622 assert(t->stack_base() != NULL, "stack_base was not initialized");
623
624 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
625 sigset_t mask_all, old_sigset;
626 sigfillset(&mask_all);
627 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
628 _expand_stack_to(addr);
629 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
630 return true;
631 }
632 return false;
633 }
634
635 //////////////////////////////////////////////////////////////////////////////
636 // create new thread
637
638 // Thread start routine for all newly created threads
639 static void *thread_native_entry(Thread *thread) {
640 // Try to randomize the cache line index of hot stack frames.
641 // This helps when threads of the same stack traces evict each other's
642 // cache lines. The threads can be either from the same JVM instance, or
643 // from different JVM instances. The benefit is especially true for
644 // processors with hyperthreading technology.
645 static int counter = 0;
646 int pid = os::current_process_id();
647 alloca(((pid ^ counter++) & 7) * 128);
648
649 thread->initialize_thread_current();
650
651 OSThread* osthread = thread->osthread();
652 Monitor* sync = osthread->startThread_lock();
653
654 osthread->set_thread_id(os::current_thread_id());
655
656 log_info(os, thread)("Thread is alive (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
657 os::current_thread_id(), (uintx) pthread_self());
658
659 if (UseNUMA) {
660 int lgrp_id = os::numa_get_group_id();
661 if (lgrp_id != -1) {
662 thread->set_lgrp_id(lgrp_id);
663 }
664 }
665 // initialize signal mask for this thread
666 os::Linux::hotspot_sigmask(thread);
667
668 // initialize floating point control register
669 os::Linux::init_thread_fpu_state();
670
671 // handshaking with parent thread
672 {
673 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
674
675 // notify parent thread
676 osthread->set_state(INITIALIZED);
677 sync->notify_all();
678
679 // wait until os::start_thread()
680 while (osthread->get_state() == INITIALIZED) {
681 sync->wait(Mutex::_no_safepoint_check_flag);
682 }
683 }
684
685 // call one more level start routine
686 thread->run();
687
688 log_info(os, thread)("Thread finished (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
689 os::current_thread_id(), (uintx) pthread_self());
690
691 // If a thread has not deleted itself ("delete this") as part of its
692 // termination sequence, we have to ensure thread-local-storage is
693 // cleared before we actually terminate. No threads should ever be
694 // deleted asynchronously with respect to their termination.
695 if (Thread::current_or_null_safe() != NULL) {
696 assert(Thread::current_or_null_safe() == thread, "current thread is wrong");
697 thread->clear_thread_current();
698 }
699
700 return 0;
701 }
702
703 bool os::create_thread(Thread* thread, ThreadType thr_type,
704 size_t stack_size) {
705 assert(thread->osthread() == NULL, "caller responsible");
706
707 // Allocate the OSThread object
708 OSThread* osthread = new OSThread(NULL, NULL);
709 if (osthread == NULL) {
710 return false;
711 }
712
713 // set the correct thread state
714 osthread->set_thread_type(thr_type);
715
716 // Initial state is ALLOCATED but not INITIALIZED
717 osthread->set_state(ALLOCATED);
718
719 thread->set_osthread(osthread);
720
721 // init thread attributes
722 pthread_attr_t attr;
723 pthread_attr_init(&attr);
724 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
725
726 // stack size
727 // calculate stack size if it's not specified by caller
728 if (stack_size == 0) {
729 stack_size = os::Linux::default_stack_size(thr_type);
730
731 switch (thr_type) {
732 case os::java_thread:
733 // Java threads use ThreadStackSize which default value can be
734 // changed with the flag -Xss
735 assert(JavaThread::stack_size_at_create() > 0, "this should be set");
736 stack_size = JavaThread::stack_size_at_create();
737 break;
738 case os::compiler_thread:
739 if (CompilerThreadStackSize > 0) {
740 stack_size = (size_t)(CompilerThreadStackSize * K);
741 break;
742 } // else fall through:
743 // use VMThreadStackSize if CompilerThreadStackSize is not defined
744 case os::vm_thread:
745 case os::pgc_thread:
746 case os::cgc_thread:
747 case os::watcher_thread:
748 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
749 break;
750 }
751 }
752
753 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
754 pthread_attr_setstacksize(&attr, stack_size);
755
756 // glibc guard page
757 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
758
759 ThreadState state;
760
761 {
762 pthread_t tid;
763 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) thread_native_entry, thread);
764
765 char buf[64];
766 if (ret == 0) {
767 log_info(os, thread)("Thread started (pthread id: " UINTX_FORMAT ", attributes: %s). ",
768 (uintx) tid, os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
769 } else {
770 log_warning(os, thread)("Failed to start thread - pthread_create failed (%s) for attributes: %s.",
771 os::errno_name(ret), os::Posix::describe_pthread_attr(buf, sizeof(buf), &attr));
772 }
773
774 pthread_attr_destroy(&attr);
775
776 if (ret != 0) {
777 // Need to clean up stuff we've allocated so far
778 thread->set_osthread(NULL);
779 delete osthread;
780 return false;
781 }
782
783 // Store pthread info into the OSThread
784 osthread->set_pthread_id(tid);
785
786 // Wait until child thread is either initialized or aborted
787 {
788 Monitor* sync_with_child = osthread->startThread_lock();
789 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
790 while ((state = osthread->get_state()) == ALLOCATED) {
791 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
792 }
793 }
794 }
795
796 // Aborted due to thread limit being reached
797 if (state == ZOMBIE) {
798 thread->set_osthread(NULL);
799 delete osthread;
800 return false;
801 }
802
803 // The thread is returned suspended (in state INITIALIZED),
804 // and is started higher up in the call chain
805 assert(state == INITIALIZED, "race condition");
806 return true;
807 }
808
809 /////////////////////////////////////////////////////////////////////////////
810 // attach existing thread
811
812 // bootstrap the main thread
813 bool os::create_main_thread(JavaThread* thread) {
814 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
815 return create_attached_thread(thread);
816 }
817
818 bool os::create_attached_thread(JavaThread* thread) {
819 #ifdef ASSERT
820 thread->verify_not_published();
821 #endif
822
823 // Allocate the OSThread object
824 OSThread* osthread = new OSThread(NULL, NULL);
825
826 if (osthread == NULL) {
827 return false;
828 }
829
830 // Store pthread info into the OSThread
831 osthread->set_thread_id(os::Linux::gettid());
832 osthread->set_pthread_id(::pthread_self());
833
834 // initialize floating point control register
835 os::Linux::init_thread_fpu_state();
836
837 // Initial thread state is RUNNABLE
838 osthread->set_state(RUNNABLE);
839
840 thread->set_osthread(osthread);
841
842 if (UseNUMA) {
843 int lgrp_id = os::numa_get_group_id();
844 if (lgrp_id != -1) {
845 thread->set_lgrp_id(lgrp_id);
846 }
847 }
848
849 if (os::Linux::is_initial_thread()) {
850 // If current thread is initial thread, its stack is mapped on demand,
851 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
852 // the entire stack region to avoid SEGV in stack banging.
853 // It is also useful to get around the heap-stack-gap problem on SuSE
854 // kernel (see 4821821 for details). We first expand stack to the top
855 // of yellow zone, then enable stack yellow zone (order is significant,
856 // enabling yellow zone first will crash JVM on SuSE Linux), so there
857 // is no gap between the last two virtual memory regions.
858
859 JavaThread *jt = (JavaThread *)thread;
860 address addr = jt->stack_reserved_zone_base();
861 assert(addr != NULL, "initialization problem?");
862 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
863
864 osthread->set_expanding_stack();
865 os::Linux::manually_expand_stack(jt, addr);
866 osthread->clear_expanding_stack();
867 }
868
869 // initialize signal mask for this thread
870 // and save the caller's signal mask
871 os::Linux::hotspot_sigmask(thread);
872
873 log_info(os, thread)("Thread attached (tid: " UINTX_FORMAT ", pthread id: " UINTX_FORMAT ").",
874 os::current_thread_id(), (uintx) pthread_self());
875
876 return true;
877 }
878
879 void os::pd_start_thread(Thread* thread) {
880 OSThread * osthread = thread->osthread();
881 assert(osthread->get_state() != INITIALIZED, "just checking");
882 Monitor* sync_with_child = osthread->startThread_lock();
883 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
884 sync_with_child->notify();
885 }
886
887 // Free Linux resources related to the OSThread
888 void os::free_thread(OSThread* osthread) {
889 assert(osthread != NULL, "osthread not set");
890
891 // We are told to free resources of the argument thread,
892 // but we can only really operate on the current thread.
893 assert(Thread::current()->osthread() == osthread,
894 "os::free_thread but not current thread");
895
896 #ifdef ASSERT
897 sigset_t current;
898 sigemptyset(¤t);
899 pthread_sigmask(SIG_SETMASK, NULL, ¤t);
900 assert(!sigismember(¤t, SR_signum), "SR signal should not be blocked!");
901 #endif
902
903 // Restore caller's signal mask
904 sigset_t sigmask = osthread->caller_sigmask();
905 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
906
907 delete osthread;
908 }
909
910 //////////////////////////////////////////////////////////////////////////////
911 // initial thread
912
913 // Check if current thread is the initial thread, similar to Solaris thr_main.
914 bool os::Linux::is_initial_thread(void) {
915 char dummy;
916 // If called before init complete, thread stack bottom will be null.
917 // Can be called if fatal error occurs before initialization.
918 if (initial_thread_stack_bottom() == NULL) return false;
919 assert(initial_thread_stack_bottom() != NULL &&
920 initial_thread_stack_size() != 0,
921 "os::init did not locate initial thread's stack region");
922 if ((address)&dummy >= initial_thread_stack_bottom() &&
923 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
924 return true;
925 } else {
926 return false;
927 }
928 }
929
930 // Find the virtual memory area that contains addr
931 static bool find_vma(address addr, address* vma_low, address* vma_high) {
932 FILE *fp = fopen("/proc/self/maps", "r");
933 if (fp) {
934 address low, high;
935 while (!feof(fp)) {
936 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
937 if (low <= addr && addr < high) {
938 if (vma_low) *vma_low = low;
939 if (vma_high) *vma_high = high;
940 fclose(fp);
941 return true;
942 }
943 }
944 for (;;) {
945 int ch = fgetc(fp);
946 if (ch == EOF || ch == (int)'\n') break;
947 }
948 }
949 fclose(fp);
950 }
951 return false;
952 }
953
954 // Locate initial thread stack. This special handling of initial thread stack
955 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
956 // bogus value for initial thread.
957 void os::Linux::capture_initial_stack(size_t max_size) {
958 // stack size is the easy part, get it from RLIMIT_STACK
959 size_t stack_size;
960 struct rlimit rlim;
961 getrlimit(RLIMIT_STACK, &rlim);
962 stack_size = rlim.rlim_cur;
963
964 // 6308388: a bug in ld.so will relocate its own .data section to the
965 // lower end of primordial stack; reduce ulimit -s value a little bit
966 // so we won't install guard page on ld.so's data section.
967 stack_size -= 2 * page_size();
968
969 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
970 // 7.1, in both cases we will get 2G in return value.
971 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
972 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
973 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
974 // in case other parts in glibc still assumes 2M max stack size.
975 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
976 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
977 if (stack_size > 2 * K * K IA64_ONLY(*2)) {
978 stack_size = 2 * K * K IA64_ONLY(*2);
979 }
980 // Try to figure out where the stack base (top) is. This is harder.
981 //
982 // When an application is started, glibc saves the initial stack pointer in
983 // a global variable "__libc_stack_end", which is then used by system
984 // libraries. __libc_stack_end should be pretty close to stack top. The
985 // variable is available since the very early days. However, because it is
986 // a private interface, it could disappear in the future.
987 //
988 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
989 // to __libc_stack_end, it is very close to stack top, but isn't the real
990 // stack top. Note that /proc may not exist if VM is running as a chroot
991 // program, so reading /proc/<pid>/stat could fail. Also the contents of
992 // /proc/<pid>/stat could change in the future (though unlikely).
993 //
994 // We try __libc_stack_end first. If that doesn't work, look for
995 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
996 // as a hint, which should work well in most cases.
997
998 uintptr_t stack_start;
999
1000 // try __libc_stack_end first
1001 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1002 if (p && *p) {
1003 stack_start = *p;
1004 } else {
1005 // see if we can get the start_stack field from /proc/self/stat
1006 FILE *fp;
1007 int pid;
1008 char state;
1009 int ppid;
1010 int pgrp;
1011 int session;
1012 int nr;
1013 int tpgrp;
1014 unsigned long flags;
1015 unsigned long minflt;
1016 unsigned long cminflt;
1017 unsigned long majflt;
1018 unsigned long cmajflt;
1019 unsigned long utime;
1020 unsigned long stime;
1021 long cutime;
1022 long cstime;
1023 long prio;
1024 long nice;
1025 long junk;
1026 long it_real;
1027 uintptr_t start;
1028 uintptr_t vsize;
1029 intptr_t rss;
1030 uintptr_t rsslim;
1031 uintptr_t scodes;
1032 uintptr_t ecode;
1033 int i;
1034
1035 // Figure what the primordial thread stack base is. Code is inspired
1036 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1037 // followed by command name surrounded by parentheses, state, etc.
1038 char stat[2048];
1039 int statlen;
1040
1041 fp = fopen("/proc/self/stat", "r");
1042 if (fp) {
1043 statlen = fread(stat, 1, 2047, fp);
1044 stat[statlen] = '\0';
1045 fclose(fp);
1046
1047 // Skip pid and the command string. Note that we could be dealing with
1048 // weird command names, e.g. user could decide to rename java launcher
1049 // to "java 1.4.2 :)", then the stat file would look like
1050 // 1234 (java 1.4.2 :)) R ... ...
1051 // We don't really need to know the command string, just find the last
1052 // occurrence of ")" and then start parsing from there. See bug 4726580.
1053 char * s = strrchr(stat, ')');
1054
1055 i = 0;
1056 if (s) {
1057 // Skip blank chars
1058 do { s++; } while (s && isspace(*s));
1059
1060 #define _UFM UINTX_FORMAT
1061 #define _DFM INTX_FORMAT
1062
1063 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1064 // 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
1065 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,
1066 &state, // 3 %c
1067 &ppid, // 4 %d
1068 &pgrp, // 5 %d
1069 &session, // 6 %d
1070 &nr, // 7 %d
1071 &tpgrp, // 8 %d
1072 &flags, // 9 %lu
1073 &minflt, // 10 %lu
1074 &cminflt, // 11 %lu
1075 &majflt, // 12 %lu
1076 &cmajflt, // 13 %lu
1077 &utime, // 14 %lu
1078 &stime, // 15 %lu
1079 &cutime, // 16 %ld
1080 &cstime, // 17 %ld
1081 &prio, // 18 %ld
1082 &nice, // 19 %ld
1083 &junk, // 20 %ld
1084 &it_real, // 21 %ld
1085 &start, // 22 UINTX_FORMAT
1086 &vsize, // 23 UINTX_FORMAT
1087 &rss, // 24 INTX_FORMAT
1088 &rsslim, // 25 UINTX_FORMAT
1089 &scodes, // 26 UINTX_FORMAT
1090 &ecode, // 27 UINTX_FORMAT
1091 &stack_start); // 28 UINTX_FORMAT
1092 }
1093
1094 #undef _UFM
1095 #undef _DFM
1096
1097 if (i != 28 - 2) {
1098 assert(false, "Bad conversion from /proc/self/stat");
1099 // product mode - assume we are the initial thread, good luck in the
1100 // embedded case.
1101 warning("Can't detect initial thread stack location - bad conversion");
1102 stack_start = (uintptr_t) &rlim;
1103 }
1104 } else {
1105 // For some reason we can't open /proc/self/stat (for example, running on
1106 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1107 // most cases, so don't abort:
1108 warning("Can't detect initial thread stack location - no /proc/self/stat");
1109 stack_start = (uintptr_t) &rlim;
1110 }
1111 }
1112
1113 // Now we have a pointer (stack_start) very close to the stack top, the
1114 // next thing to do is to figure out the exact location of stack top. We
1115 // can find out the virtual memory area that contains stack_start by
1116 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1117 // and its upper limit is the real stack top. (again, this would fail if
1118 // running inside chroot, because /proc may not exist.)
1119
1120 uintptr_t stack_top;
1121 address low, high;
1122 if (find_vma((address)stack_start, &low, &high)) {
1123 // success, "high" is the true stack top. (ignore "low", because initial
1124 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1125 stack_top = (uintptr_t)high;
1126 } else {
1127 // failed, likely because /proc/self/maps does not exist
1128 warning("Can't detect initial thread stack location - find_vma failed");
1129 // best effort: stack_start is normally within a few pages below the real
1130 // stack top, use it as stack top, and reduce stack size so we won't put
1131 // guard page outside stack.
1132 stack_top = stack_start;
1133 stack_size -= 16 * page_size();
1134 }
1135
1136 // stack_top could be partially down the page so align it
1137 stack_top = align_size_up(stack_top, page_size());
1138
1139 if (max_size && stack_size > max_size) {
1140 _initial_thread_stack_size = max_size;
1141 } else {
1142 _initial_thread_stack_size = stack_size;
1143 }
1144
1145 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1146 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1147 }
1148
1149 ////////////////////////////////////////////////////////////////////////////////
1150 // time support
1151
1152 // Time since start-up in seconds to a fine granularity.
1153 // Used by VMSelfDestructTimer and the MemProfiler.
1154 double os::elapsedTime() {
1155
1156 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1157 }
1158
1159 jlong os::elapsed_counter() {
1160 return javaTimeNanos() - initial_time_count;
1161 }
1162
1163 jlong os::elapsed_frequency() {
1164 return NANOSECS_PER_SEC; // nanosecond resolution
1165 }
1166
1167 bool os::supports_vtime() { return true; }
1168 bool os::enable_vtime() { return false; }
1169 bool os::vtime_enabled() { return false; }
1170
1171 double os::elapsedVTime() {
1172 struct rusage usage;
1173 int retval = getrusage(RUSAGE_THREAD, &usage);
1174 if (retval == 0) {
1175 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);
1176 } else {
1177 // better than nothing, but not much
1178 return elapsedTime();
1179 }
1180 }
1181
1182 jlong os::javaTimeMillis() {
1183 timeval time;
1184 int status = gettimeofday(&time, NULL);
1185 assert(status != -1, "linux error");
1186 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1187 }
1188
1189 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1190 timeval time;
1191 int status = gettimeofday(&time, NULL);
1192 assert(status != -1, "linux error");
1193 seconds = jlong(time.tv_sec);
1194 nanos = jlong(time.tv_usec) * 1000;
1195 }
1196
1197
1198 #ifndef CLOCK_MONOTONIC
1199 #define CLOCK_MONOTONIC (1)
1200 #endif
1201
1202 void os::Linux::clock_init() {
1203 // we do dlopen's in this particular order due to bug in linux
1204 // dynamical loader (see 6348968) leading to crash on exit
1205 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1206 if (handle == NULL) {
1207 handle = dlopen("librt.so", RTLD_LAZY);
1208 }
1209
1210 if (handle) {
1211 int (*clock_getres_func)(clockid_t, struct timespec*) =
1212 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1213 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1214 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1215 if (clock_getres_func && clock_gettime_func) {
1216 // See if monotonic clock is supported by the kernel. Note that some
1217 // early implementations simply return kernel jiffies (updated every
1218 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1219 // for nano time (though the monotonic property is still nice to have).
1220 // It's fixed in newer kernels, however clock_getres() still returns
1221 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1222 // resolution for now. Hopefully as people move to new kernels, this
1223 // won't be a problem.
1224 struct timespec res;
1225 struct timespec tp;
1226 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1227 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1228 // yes, monotonic clock is supported
1229 _clock_gettime = clock_gettime_func;
1230 return;
1231 } else {
1232 // close librt if there is no monotonic clock
1233 dlclose(handle);
1234 }
1235 }
1236 }
1237 warning("No monotonic clock was available - timed services may " \
1238 "be adversely affected if the time-of-day clock changes");
1239 }
1240
1241 #ifndef SYS_clock_getres
1242 #if defined(IA32) || defined(AMD64)
1243 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1244 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1245 #else
1246 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1247 #define sys_clock_getres(x,y) -1
1248 #endif
1249 #else
1250 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1251 #endif
1252
1253 void os::Linux::fast_thread_clock_init() {
1254 if (!UseLinuxPosixThreadCPUClocks) {
1255 return;
1256 }
1257 clockid_t clockid;
1258 struct timespec tp;
1259 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1260 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1261
1262 // Switch to using fast clocks for thread cpu time if
1263 // the sys_clock_getres() returns 0 error code.
1264 // Note, that some kernels may support the current thread
1265 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1266 // returned by the pthread_getcpuclockid().
1267 // If the fast Posix clocks are supported then the sys_clock_getres()
1268 // must return at least tp.tv_sec == 0 which means a resolution
1269 // better than 1 sec. This is extra check for reliability.
1270
1271 if (pthread_getcpuclockid_func &&
1272 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1273 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1274 _supports_fast_thread_cpu_time = true;
1275 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1276 }
1277 }
1278
1279 jlong os::javaTimeNanos() {
1280 if (os::supports_monotonic_clock()) {
1281 struct timespec tp;
1282 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1283 assert(status == 0, "gettime error");
1284 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1285 return result;
1286 } else {
1287 timeval time;
1288 int status = gettimeofday(&time, NULL);
1289 assert(status != -1, "linux error");
1290 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1291 return 1000 * usecs;
1292 }
1293 }
1294
1295 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1296 if (os::supports_monotonic_clock()) {
1297 info_ptr->max_value = ALL_64_BITS;
1298
1299 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1300 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1301 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1302 } else {
1303 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1304 info_ptr->max_value = ALL_64_BITS;
1305
1306 // gettimeofday is a real time clock so it skips
1307 info_ptr->may_skip_backward = true;
1308 info_ptr->may_skip_forward = true;
1309 }
1310
1311 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1312 }
1313
1314 // Return the real, user, and system times in seconds from an
1315 // arbitrary fixed point in the past.
1316 bool os::getTimesSecs(double* process_real_time,
1317 double* process_user_time,
1318 double* process_system_time) {
1319 struct tms ticks;
1320 clock_t real_ticks = times(&ticks);
1321
1322 if (real_ticks == (clock_t) (-1)) {
1323 return false;
1324 } else {
1325 double ticks_per_second = (double) clock_tics_per_sec;
1326 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1327 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1328 *process_real_time = ((double) real_ticks) / ticks_per_second;
1329
1330 return true;
1331 }
1332 }
1333
1334
1335 char * os::local_time_string(char *buf, size_t buflen) {
1336 struct tm t;
1337 time_t long_time;
1338 time(&long_time);
1339 localtime_r(&long_time, &t);
1340 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1341 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1342 t.tm_hour, t.tm_min, t.tm_sec);
1343 return buf;
1344 }
1345
1346 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1347 return localtime_r(clock, res);
1348 }
1349
1350 ////////////////////////////////////////////////////////////////////////////////
1351 // runtime exit support
1352
1353 // Note: os::shutdown() might be called very early during initialization, or
1354 // called from signal handler. Before adding something to os::shutdown(), make
1355 // sure it is async-safe and can handle partially initialized VM.
1356 void os::shutdown() {
1357
1358 // allow PerfMemory to attempt cleanup of any persistent resources
1359 perfMemory_exit();
1360
1361 // needs to remove object in file system
1362 AttachListener::abort();
1363
1364 // flush buffered output, finish log files
1365 ostream_abort();
1366
1367 // Check for abort hook
1368 abort_hook_t abort_hook = Arguments::abort_hook();
1369 if (abort_hook != NULL) {
1370 abort_hook();
1371 }
1372
1373 }
1374
1375 // Note: os::abort() might be called very early during initialization, or
1376 // called from signal handler. Before adding something to os::abort(), make
1377 // sure it is async-safe and can handle partially initialized VM.
1378 void os::abort(bool dump_core, void* siginfo, const void* context) {
1379 os::shutdown();
1380 if (dump_core) {
1381 #ifndef PRODUCT
1382 fdStream out(defaultStream::output_fd());
1383 out.print_raw("Current thread is ");
1384 char buf[16];
1385 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1386 out.print_raw_cr(buf);
1387 out.print_raw_cr("Dumping core ...");
1388 #endif
1389 ::abort(); // dump core
1390 }
1391
1392 ::exit(1);
1393 }
1394
1395 // Die immediately, no exit hook, no abort hook, no cleanup.
1396 void os::die() {
1397 ::abort();
1398 }
1399
1400
1401 // This method is a copy of JDK's sysGetLastErrorString
1402 // from src/solaris/hpi/src/system_md.c
1403
1404 size_t os::lasterror(char *buf, size_t len) {
1405 if (errno == 0) return 0;
1406
1407 const char *s = os::strerror(errno);
1408 size_t n = ::strlen(s);
1409 if (n >= len) {
1410 n = len - 1;
1411 }
1412 ::strncpy(buf, s, n);
1413 buf[n] = '\0';
1414 return n;
1415 }
1416
1417 // thread_id is kernel thread id (similar to Solaris LWP id)
1418 intx os::current_thread_id() { return os::Linux::gettid(); }
1419 int os::current_process_id() {
1420 return ::getpid();
1421 }
1422
1423 // DLL functions
1424
1425 const char* os::dll_file_extension() { return ".so"; }
1426
1427 // This must be hard coded because it's the system's temporary
1428 // directory not the java application's temp directory, ala java.io.tmpdir.
1429 const char* os::get_temp_directory() { return "/tmp"; }
1430
1431 static bool file_exists(const char* filename) {
1432 struct stat statbuf;
1433 if (filename == NULL || strlen(filename) == 0) {
1434 return false;
1435 }
1436 return os::stat(filename, &statbuf) == 0;
1437 }
1438
1439 bool os::dll_build_name(char* buffer, size_t buflen,
1440 const char* pname, const char* fname) {
1441 bool retval = false;
1442 // Copied from libhpi
1443 const size_t pnamelen = pname ? strlen(pname) : 0;
1444
1445 // Return error on buffer overflow.
1446 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1447 return retval;
1448 }
1449
1450 if (pnamelen == 0) {
1451 snprintf(buffer, buflen, "lib%s.so", fname);
1452 retval = true;
1453 } else if (strchr(pname, *os::path_separator()) != NULL) {
1454 int n;
1455 char** pelements = split_path(pname, &n);
1456 if (pelements == NULL) {
1457 return false;
1458 }
1459 for (int i = 0; i < n; i++) {
1460 // Really shouldn't be NULL, but check can't hurt
1461 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1462 continue; // skip the empty path values
1463 }
1464 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1465 if (file_exists(buffer)) {
1466 retval = true;
1467 break;
1468 }
1469 }
1470 // release the storage
1471 for (int i = 0; i < n; i++) {
1472 if (pelements[i] != NULL) {
1473 FREE_C_HEAP_ARRAY(char, pelements[i]);
1474 }
1475 }
1476 if (pelements != NULL) {
1477 FREE_C_HEAP_ARRAY(char*, pelements);
1478 }
1479 } else {
1480 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1481 retval = true;
1482 }
1483 return retval;
1484 }
1485
1486 // check if addr is inside libjvm.so
1487 bool os::address_is_in_vm(address addr) {
1488 static address libjvm_base_addr;
1489 Dl_info dlinfo;
1490
1491 if (libjvm_base_addr == NULL) {
1492 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1493 libjvm_base_addr = (address)dlinfo.dli_fbase;
1494 }
1495 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1496 }
1497
1498 if (dladdr((void *)addr, &dlinfo) != 0) {
1499 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1500 }
1501
1502 return false;
1503 }
1504
1505 bool os::dll_address_to_function_name(address addr, char *buf,
1506 int buflen, int *offset,
1507 bool demangle) {
1508 // buf is not optional, but offset is optional
1509 assert(buf != NULL, "sanity check");
1510
1511 Dl_info dlinfo;
1512
1513 if (dladdr((void*)addr, &dlinfo) != 0) {
1514 // see if we have a matching symbol
1515 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1516 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1517 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1518 }
1519 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1520 return true;
1521 }
1522 // no matching symbol so try for just file info
1523 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1524 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1525 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1526 return true;
1527 }
1528 }
1529 }
1530
1531 buf[0] = '\0';
1532 if (offset != NULL) *offset = -1;
1533 return false;
1534 }
1535
1536 struct _address_to_library_name {
1537 address addr; // input : memory address
1538 size_t buflen; // size of fname
1539 char* fname; // output: library name
1540 address base; // library base addr
1541 };
1542
1543 static int address_to_library_name_callback(struct dl_phdr_info *info,
1544 size_t size, void *data) {
1545 int i;
1546 bool found = false;
1547 address libbase = NULL;
1548 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1549
1550 // iterate through all loadable segments
1551 for (i = 0; i < info->dlpi_phnum; i++) {
1552 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1553 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1554 // base address of a library is the lowest address of its loaded
1555 // segments.
1556 if (libbase == NULL || libbase > segbase) {
1557 libbase = segbase;
1558 }
1559 // see if 'addr' is within current segment
1560 if (segbase <= d->addr &&
1561 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1562 found = true;
1563 }
1564 }
1565 }
1566
1567 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1568 // so dll_address_to_library_name() can fall through to use dladdr() which
1569 // can figure out executable name from argv[0].
1570 if (found && info->dlpi_name && info->dlpi_name[0]) {
1571 d->base = libbase;
1572 if (d->fname) {
1573 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1574 }
1575 return 1;
1576 }
1577 return 0;
1578 }
1579
1580 bool os::dll_address_to_library_name(address addr, char* buf,
1581 int buflen, int* offset) {
1582 // buf is not optional, but offset is optional
1583 assert(buf != NULL, "sanity check");
1584
1585 Dl_info dlinfo;
1586 struct _address_to_library_name data;
1587
1588 // There is a bug in old glibc dladdr() implementation that it could resolve
1589 // to wrong library name if the .so file has a base address != NULL. Here
1590 // we iterate through the program headers of all loaded libraries to find
1591 // out which library 'addr' really belongs to. This workaround can be
1592 // removed once the minimum requirement for glibc is moved to 2.3.x.
1593 data.addr = addr;
1594 data.fname = buf;
1595 data.buflen = buflen;
1596 data.base = NULL;
1597 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1598
1599 if (rslt) {
1600 // buf already contains library name
1601 if (offset) *offset = addr - data.base;
1602 return true;
1603 }
1604 if (dladdr((void*)addr, &dlinfo) != 0) {
1605 if (dlinfo.dli_fname != NULL) {
1606 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1607 }
1608 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1609 *offset = addr - (address)dlinfo.dli_fbase;
1610 }
1611 return true;
1612 }
1613
1614 buf[0] = '\0';
1615 if (offset) *offset = -1;
1616 return false;
1617 }
1618
1619 // Loads .dll/.so and
1620 // in case of error it checks if .dll/.so was built for the
1621 // same architecture as Hotspot is running on
1622
1623
1624 // Remember the stack's state. The Linux dynamic linker will change
1625 // the stack to 'executable' at most once, so we must safepoint only once.
1626 bool os::Linux::_stack_is_executable = false;
1627
1628 // VM operation that loads a library. This is necessary if stack protection
1629 // of the Java stacks can be lost during loading the library. If we
1630 // do not stop the Java threads, they can stack overflow before the stacks
1631 // are protected again.
1632 class VM_LinuxDllLoad: public VM_Operation {
1633 private:
1634 const char *_filename;
1635 char *_ebuf;
1636 int _ebuflen;
1637 void *_lib;
1638 public:
1639 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1640 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1641 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1642 void doit() {
1643 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1644 os::Linux::_stack_is_executable = true;
1645 }
1646 void* loaded_library() { return _lib; }
1647 };
1648
1649 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1650 void * result = NULL;
1651 bool load_attempted = false;
1652
1653 // Check whether the library to load might change execution rights
1654 // of the stack. If they are changed, the protection of the stack
1655 // guard pages will be lost. We need a safepoint to fix this.
1656 //
1657 // See Linux man page execstack(8) for more info.
1658 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1659 ElfFile ef(filename);
1660 if (!ef.specifies_noexecstack()) {
1661 if (!is_init_completed()) {
1662 os::Linux::_stack_is_executable = true;
1663 // This is OK - No Java threads have been created yet, and hence no
1664 // stack guard pages to fix.
1665 //
1666 // This should happen only when you are building JDK7 using a very
1667 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1668 //
1669 // Dynamic loader will make all stacks executable after
1670 // this function returns, and will not do that again.
1671 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1672 } else {
1673 warning("You have loaded library %s which might have disabled stack guard. "
1674 "The VM will try to fix the stack guard now.\n"
1675 "It's highly recommended that you fix the library with "
1676 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1677 filename);
1678
1679 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1680 JavaThread *jt = JavaThread::current();
1681 if (jt->thread_state() != _thread_in_native) {
1682 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1683 // that requires ExecStack. Cannot enter safe point. Let's give up.
1684 warning("Unable to fix stack guard. Giving up.");
1685 } else {
1686 if (!LoadExecStackDllInVMThread) {
1687 // This is for the case where the DLL has an static
1688 // constructor function that executes JNI code. We cannot
1689 // load such DLLs in the VMThread.
1690 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1691 }
1692
1693 ThreadInVMfromNative tiv(jt);
1694 debug_only(VMNativeEntryWrapper vew;)
1695
1696 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1697 VMThread::execute(&op);
1698 if (LoadExecStackDllInVMThread) {
1699 result = op.loaded_library();
1700 }
1701 load_attempted = true;
1702 }
1703 }
1704 }
1705 }
1706
1707 if (!load_attempted) {
1708 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1709 }
1710
1711 if (result != NULL) {
1712 // Successful loading
1713 return result;
1714 }
1715
1716 Elf32_Ehdr elf_head;
1717 int diag_msg_max_length=ebuflen-strlen(ebuf);
1718 char* diag_msg_buf=ebuf+strlen(ebuf);
1719
1720 if (diag_msg_max_length==0) {
1721 // No more space in ebuf for additional diagnostics message
1722 return NULL;
1723 }
1724
1725
1726 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1727
1728 if (file_descriptor < 0) {
1729 // Can't open library, report dlerror() message
1730 return NULL;
1731 }
1732
1733 bool failed_to_read_elf_head=
1734 (sizeof(elf_head)!=
1735 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1736
1737 ::close(file_descriptor);
1738 if (failed_to_read_elf_head) {
1739 // file i/o error - report dlerror() msg
1740 return NULL;
1741 }
1742
1743 typedef struct {
1744 Elf32_Half code; // Actual value as defined in elf.h
1745 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1746 unsigned char elf_class; // 32 or 64 bit
1747 unsigned char endianess; // MSB or LSB
1748 char* name; // String representation
1749 } arch_t;
1750
1751 #ifndef EM_486
1752 #define EM_486 6 /* Intel 80486 */
1753 #endif
1754 #ifndef EM_AARCH64
1755 #define EM_AARCH64 183 /* ARM AARCH64 */
1756 #endif
1757
1758 static const arch_t arch_array[]={
1759 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1760 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1761 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1762 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1763 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1764 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1765 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1766 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1767 #if defined(VM_LITTLE_ENDIAN)
1768 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1769 #else
1770 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1771 #endif
1772 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1773 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1774 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1775 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1776 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1777 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1778 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1779 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1780 };
1781
1782 #if (defined IA32)
1783 static Elf32_Half running_arch_code=EM_386;
1784 #elif (defined AMD64)
1785 static Elf32_Half running_arch_code=EM_X86_64;
1786 #elif (defined IA64)
1787 static Elf32_Half running_arch_code=EM_IA_64;
1788 #elif (defined __sparc) && (defined _LP64)
1789 static Elf32_Half running_arch_code=EM_SPARCV9;
1790 #elif (defined __sparc) && (!defined _LP64)
1791 static Elf32_Half running_arch_code=EM_SPARC;
1792 #elif (defined __powerpc64__)
1793 static Elf32_Half running_arch_code=EM_PPC64;
1794 #elif (defined __powerpc__)
1795 static Elf32_Half running_arch_code=EM_PPC;
1796 #elif (defined ARM)
1797 static Elf32_Half running_arch_code=EM_ARM;
1798 #elif (defined S390)
1799 static Elf32_Half running_arch_code=EM_S390;
1800 #elif (defined ALPHA)
1801 static Elf32_Half running_arch_code=EM_ALPHA;
1802 #elif (defined MIPSEL)
1803 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1804 #elif (defined PARISC)
1805 static Elf32_Half running_arch_code=EM_PARISC;
1806 #elif (defined MIPS)
1807 static Elf32_Half running_arch_code=EM_MIPS;
1808 #elif (defined M68K)
1809 static Elf32_Half running_arch_code=EM_68K;
1810 #elif (defined AARCH64)
1811 static Elf32_Half running_arch_code=EM_AARCH64;
1812 #else
1813 #error Method os::dll_load requires that one of following is defined:\
1814 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64
1815 #endif
1816
1817 // Identify compatability class for VM's architecture and library's architecture
1818 // Obtain string descriptions for architectures
1819
1820 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1821 int running_arch_index=-1;
1822
1823 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1824 if (running_arch_code == arch_array[i].code) {
1825 running_arch_index = i;
1826 }
1827 if (lib_arch.code == arch_array[i].code) {
1828 lib_arch.compat_class = arch_array[i].compat_class;
1829 lib_arch.name = arch_array[i].name;
1830 }
1831 }
1832
1833 assert(running_arch_index != -1,
1834 "Didn't find running architecture code (running_arch_code) in arch_array");
1835 if (running_arch_index == -1) {
1836 // Even though running architecture detection failed
1837 // we may still continue with reporting dlerror() message
1838 return NULL;
1839 }
1840
1841 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1842 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1843 return NULL;
1844 }
1845
1846 #ifndef S390
1847 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1848 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1849 return NULL;
1850 }
1851 #endif // !S390
1852
1853 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1854 if (lib_arch.name!=NULL) {
1855 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1856 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1857 lib_arch.name, arch_array[running_arch_index].name);
1858 } else {
1859 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1860 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1861 lib_arch.code,
1862 arch_array[running_arch_index].name);
1863 }
1864 }
1865
1866 return NULL;
1867 }
1868
1869 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1870 int ebuflen) {
1871 void * result = ::dlopen(filename, RTLD_LAZY);
1872 if (result == NULL) {
1873 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1874 ebuf[ebuflen-1] = '\0';
1875 }
1876 return result;
1877 }
1878
1879 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1880 int ebuflen) {
1881 void * result = NULL;
1882 if (LoadExecStackDllInVMThread) {
1883 result = dlopen_helper(filename, ebuf, ebuflen);
1884 }
1885
1886 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1887 // library that requires an executable stack, or which does not have this
1888 // stack attribute set, dlopen changes the stack attribute to executable. The
1889 // read protection of the guard pages gets lost.
1890 //
1891 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1892 // may have been queued at the same time.
1893
1894 if (!_stack_is_executable) {
1895 JavaThread *jt = Threads::first();
1896
1897 while (jt) {
1898 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1899 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1900 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1901 warning("Attempt to reguard stack yellow zone failed.");
1902 }
1903 }
1904 jt = jt->next();
1905 }
1906 }
1907
1908 return result;
1909 }
1910
1911 void* os::dll_lookup(void* handle, const char* name) {
1912 void* res = dlsym(handle, name);
1913 return res;
1914 }
1915
1916 void* os::get_default_process_handle() {
1917 return (void*)::dlopen(NULL, RTLD_LAZY);
1918 }
1919
1920 static bool _print_ascii_file(const char* filename, outputStream* st) {
1921 int fd = ::open(filename, O_RDONLY);
1922 if (fd == -1) {
1923 return false;
1924 }
1925
1926 char buf[33];
1927 int bytes;
1928 buf[32] = '\0';
1929 while ((bytes = ::read(fd, buf, sizeof(buf)-1)) > 0) {
1930 st->print_raw(buf, bytes);
1931 }
1932
1933 ::close(fd);
1934
1935 return true;
1936 }
1937
1938 void os::print_dll_info(outputStream *st) {
1939 st->print_cr("Dynamic libraries:");
1940
1941 char fname[32];
1942 pid_t pid = os::Linux::gettid();
1943
1944 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1945
1946 if (!_print_ascii_file(fname, st)) {
1947 st->print("Can not get library information for pid = %d\n", pid);
1948 }
1949 }
1950
1951 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1952 FILE *procmapsFile = NULL;
1953
1954 // Open the procfs maps file for the current process
1955 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1956 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1957 char line[PATH_MAX + 100];
1958
1959 // Read line by line from 'file'
1960 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1961 u8 base, top, offset, inode;
1962 char permissions[5];
1963 char device[6];
1964 char name[PATH_MAX + 1];
1965
1966 // Parse fields from line
1967 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1968 &base, &top, permissions, &offset, device, &inode, name);
1969
1970 // Filter by device id '00:00' so that we only get file system mapped files.
1971 if (strcmp(device, "00:00") != 0) {
1972
1973 // Call callback with the fields of interest
1974 if(callback(name, (address)base, (address)top, param)) {
1975 // Oops abort, callback aborted
1976 fclose(procmapsFile);
1977 return 1;
1978 }
1979 }
1980 }
1981 fclose(procmapsFile);
1982 }
1983 return 0;
1984 }
1985
1986 void os::print_os_info_brief(outputStream* st) {
1987 os::Linux::print_distro_info(st);
1988
1989 os::Posix::print_uname_info(st);
1990
1991 os::Linux::print_libversion_info(st);
1992
1993 }
1994
1995 void os::print_os_info(outputStream* st) {
1996 st->print("OS:");
1997
1998 os::Linux::print_distro_info(st);
1999
2000 os::Posix::print_uname_info(st);
2001
2002 // Print warning if unsafe chroot environment detected
2003 if (unsafe_chroot_detected) {
2004 st->print("WARNING!! ");
2005 st->print_cr("%s", unstable_chroot_error);
2006 }
2007
2008 os::Linux::print_libversion_info(st);
2009
2010 os::Posix::print_rlimit_info(st);
2011
2012 os::Posix::print_load_average(st);
2013
2014 os::Linux::print_full_memory_info(st);
2015 }
2016
2017 // Try to identify popular distros.
2018 // Most Linux distributions have a /etc/XXX-release file, which contains
2019 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2020 // file that also contains the OS version string. Some have more than one
2021 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2022 // /etc/redhat-release.), so the order is important.
2023 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2024 // their own specific XXX-release file as well as a redhat-release file.
2025 // Because of this the XXX-release file needs to be searched for before the
2026 // redhat-release file.
2027 // Since Red Hat and SuSE have an lsb-release file that is not very descriptive the
2028 // search for redhat-release / SuSE-release needs to be before lsb-release.
2029 // Since the lsb-release file is the new standard it needs to be searched
2030 // before the older style release files.
2031 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2032 // next to last resort. The os-release file is a new standard that contains
2033 // distribution information and the system-release file seems to be an old
2034 // standard that has been replaced by the lsb-release and os-release files.
2035 // Searching for the debian_version file is the last resort. It contains
2036 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2037 // "Debian " is printed before the contents of the debian_version file.
2038
2039 const char* distro_files[] = {
2040 "/etc/oracle-release",
2041 "/etc/mandriva-release",
2042 "/etc/mandrake-release",
2043 "/etc/sun-release",
2044 "/etc/redhat-release",
2045 "/etc/SuSE-release",
2046 "/etc/lsb-release",
2047 "/etc/turbolinux-release",
2048 "/etc/gentoo-release",
2049 "/etc/ltib-release",
2050 "/etc/angstrom-version",
2051 "/etc/system-release",
2052 "/etc/os-release",
2053 NULL };
2054
2055 void os::Linux::print_distro_info(outputStream* st) {
2056 for (int i = 0;; i++) {
2057 const char* file = distro_files[i];
2058 if (file == NULL) {
2059 break; // done
2060 }
2061 // If file prints, we found it.
2062 if (_print_ascii_file(file, st)) {
2063 return;
2064 }
2065 }
2066
2067 if (file_exists("/etc/debian_version")) {
2068 st->print("Debian ");
2069 _print_ascii_file("/etc/debian_version", st);
2070 } else {
2071 st->print("Linux");
2072 }
2073 st->cr();
2074 }
2075
2076 static void parse_os_info_helper(FILE* fp, char* distro, size_t length, bool get_first_line) {
2077 char buf[256];
2078 while (fgets(buf, sizeof(buf), fp)) {
2079 // Edit out extra stuff in expected format
2080 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL || strstr(buf, "PRETTY_NAME=") != NULL) {
2081 char* ptr = strstr(buf, "\""); // the name is in quotes
2082 if (ptr != NULL) {
2083 ptr++; // go beyond first quote
2084 char* nl = strchr(ptr, '\"');
2085 if (nl != NULL) *nl = '\0';
2086 strncpy(distro, ptr, length);
2087 } else {
2088 ptr = strstr(buf, "=");
2089 ptr++; // go beyond equals then
2090 char* nl = strchr(ptr, '\n');
2091 if (nl != NULL) *nl = '\0';
2092 strncpy(distro, ptr, length);
2093 }
2094 return;
2095 } else if (get_first_line) {
2096 char* nl = strchr(buf, '\n');
2097 if (nl != NULL) *nl = '\0';
2098 strncpy(distro, buf, length);
2099 return;
2100 }
2101 }
2102 // print last line and close
2103 char* nl = strchr(buf, '\n');
2104 if (nl != NULL) *nl = '\0';
2105 strncpy(distro, buf, length);
2106 }
2107
2108 static void parse_os_info(char* distro, size_t length, const char* file) {
2109 FILE* fp = fopen(file, "r");
2110 if (fp != NULL) {
2111 // if suse format, print out first line
2112 bool get_first_line = (strcmp(file, "/etc/SuSE-release") == 0);
2113 parse_os_info_helper(fp, distro, length, get_first_line);
2114 fclose(fp);
2115 }
2116 }
2117
2118 void os::get_summary_os_info(char* buf, size_t buflen) {
2119 for (int i = 0;; i++) {
2120 const char* file = distro_files[i];
2121 if (file == NULL) {
2122 break; // ran out of distro_files
2123 }
2124 if (file_exists(file)) {
2125 parse_os_info(buf, buflen, file);
2126 return;
2127 }
2128 }
2129 // special case for debian
2130 if (file_exists("/etc/debian_version")) {
2131 strncpy(buf, "Debian ", buflen);
2132 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2133 } else {
2134 strncpy(buf, "Linux", buflen);
2135 }
2136 }
2137
2138 void os::Linux::print_libversion_info(outputStream* st) {
2139 // libc, pthread
2140 st->print("libc:");
2141 st->print("%s ", os::Linux::glibc_version());
2142 st->print("%s ", os::Linux::libpthread_version());
2143 st->cr();
2144 }
2145
2146 void os::Linux::print_full_memory_info(outputStream* st) {
2147 st->print("\n/proc/meminfo:\n");
2148 _print_ascii_file("/proc/meminfo", st);
2149 st->cr();
2150 }
2151
2152 void os::print_memory_info(outputStream* st) {
2153
2154 st->print("Memory:");
2155 st->print(" %dk page", os::vm_page_size()>>10);
2156
2157 // values in struct sysinfo are "unsigned long"
2158 struct sysinfo si;
2159 sysinfo(&si);
2160
2161 st->print(", physical " UINT64_FORMAT "k",
2162 os::physical_memory() >> 10);
2163 st->print("(" UINT64_FORMAT "k free)",
2164 os::available_memory() >> 10);
2165 st->print(", swap " UINT64_FORMAT "k",
2166 ((jlong)si.totalswap * si.mem_unit) >> 10);
2167 st->print("(" UINT64_FORMAT "k free)",
2168 ((jlong)si.freeswap * si.mem_unit) >> 10);
2169 st->cr();
2170 }
2171
2172 // Print the first "model name" line and the first "flags" line
2173 // that we find and nothing more. We assume "model name" comes
2174 // before "flags" so if we find a second "model name", then the
2175 // "flags" field is considered missing.
2176 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2177 #if defined(IA32) || defined(AMD64)
2178 // Other platforms have less repetitive cpuinfo files
2179 FILE *fp = fopen("/proc/cpuinfo", "r");
2180 if (fp) {
2181 while (!feof(fp)) {
2182 if (fgets(buf, buflen, fp)) {
2183 // Assume model name comes before flags
2184 bool model_name_printed = false;
2185 if (strstr(buf, "model name") != NULL) {
2186 if (!model_name_printed) {
2187 st->print_raw("CPU Model and flags from /proc/cpuinfo:\n");
2188 st->print_raw(buf);
2189 model_name_printed = true;
2190 } else {
2191 // model name printed but not flags? Odd, just return
2192 fclose(fp);
2193 return true;
2194 }
2195 }
2196 // print the flags line too
2197 if (strstr(buf, "flags") != NULL) {
2198 st->print_raw(buf);
2199 fclose(fp);
2200 return true;
2201 }
2202 }
2203 }
2204 fclose(fp);
2205 }
2206 #endif // x86 platforms
2207 return false;
2208 }
2209
2210 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2211 // Only print the model name if the platform provides this as a summary
2212 if (!print_model_name_and_flags(st, buf, buflen)) {
2213 st->print("\n/proc/cpuinfo:\n");
2214 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2215 st->print_cr(" <Not Available>");
2216 }
2217 }
2218 }
2219
2220 #if defined(AMD64) || defined(IA32) || defined(X32)
2221 const char* search_string = "model name";
2222 #elif defined(SPARC)
2223 const char* search_string = "cpu";
2224 #elif defined(PPC64)
2225 const char* search_string = "cpu";
2226 #else
2227 const char* search_string = "Processor";
2228 #endif
2229
2230 // Parses the cpuinfo file for string representing the model name.
2231 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2232 FILE* fp = fopen("/proc/cpuinfo", "r");
2233 if (fp != NULL) {
2234 while (!feof(fp)) {
2235 char buf[256];
2236 if (fgets(buf, sizeof(buf), fp)) {
2237 char* start = strstr(buf, search_string);
2238 if (start != NULL) {
2239 char *ptr = start + strlen(search_string);
2240 char *end = buf + strlen(buf);
2241 while (ptr != end) {
2242 // skip whitespace and colon for the rest of the name.
2243 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2244 break;
2245 }
2246 ptr++;
2247 }
2248 if (ptr != end) {
2249 // reasonable string, get rid of newline and keep the rest
2250 char* nl = strchr(buf, '\n');
2251 if (nl != NULL) *nl = '\0';
2252 strncpy(cpuinfo, ptr, length);
2253 fclose(fp);
2254 return;
2255 }
2256 }
2257 }
2258 }
2259 fclose(fp);
2260 }
2261 // cpuinfo not found or parsing failed, just print generic string. The entire
2262 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2263 #if defined(AMD64)
2264 strncpy(cpuinfo, "x86_64", length);
2265 #elif defined(IA32)
2266 strncpy(cpuinfo, "x86_32", length);
2267 #elif defined(IA64)
2268 strncpy(cpuinfo, "IA64", length);
2269 #elif defined(SPARC)
2270 strncpy(cpuinfo, "sparcv9", length);
2271 #elif defined(AARCH64)
2272 strncpy(cpuinfo, "AArch64", length);
2273 #elif defined(ARM)
2274 strncpy(cpuinfo, "ARM", length);
2275 #elif defined(PPC)
2276 strncpy(cpuinfo, "PPC64", length);
2277 #elif defined(ZERO_LIBARCH)
2278 strncpy(cpuinfo, ZERO_LIBARCH, length);
2279 #else
2280 strncpy(cpuinfo, "unknown", length);
2281 #endif
2282 }
2283
2284 static void print_signal_handler(outputStream* st, int sig,
2285 char* buf, size_t buflen);
2286
2287 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2288 st->print_cr("Signal Handlers:");
2289 print_signal_handler(st, SIGSEGV, buf, buflen);
2290 print_signal_handler(st, SIGBUS , buf, buflen);
2291 print_signal_handler(st, SIGFPE , buf, buflen);
2292 print_signal_handler(st, SIGPIPE, buf, buflen);
2293 print_signal_handler(st, SIGXFSZ, buf, buflen);
2294 print_signal_handler(st, SIGILL , buf, buflen);
2295 print_signal_handler(st, SR_signum, buf, buflen);
2296 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2297 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2298 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2299 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2300 #if defined(PPC64)
2301 print_signal_handler(st, SIGTRAP, buf, buflen);
2302 #endif
2303 }
2304
2305 static char saved_jvm_path[MAXPATHLEN] = {0};
2306
2307 // Find the full path to the current module, libjvm.so
2308 void os::jvm_path(char *buf, jint buflen) {
2309 // Error checking.
2310 if (buflen < MAXPATHLEN) {
2311 assert(false, "must use a large-enough buffer");
2312 buf[0] = '\0';
2313 return;
2314 }
2315 // Lazy resolve the path to current module.
2316 if (saved_jvm_path[0] != 0) {
2317 strcpy(buf, saved_jvm_path);
2318 return;
2319 }
2320
2321 char dli_fname[MAXPATHLEN];
2322 bool ret = dll_address_to_library_name(
2323 CAST_FROM_FN_PTR(address, os::jvm_path),
2324 dli_fname, sizeof(dli_fname), NULL);
2325 assert(ret, "cannot locate libjvm");
2326 char *rp = NULL;
2327 if (ret && dli_fname[0] != '\0') {
2328 rp = realpath(dli_fname, buf);
2329 }
2330 if (rp == NULL) {
2331 return;
2332 }
2333
2334 if (Arguments::sun_java_launcher_is_altjvm()) {
2335 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2336 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so".
2337 // If "/jre/lib/" appears at the right place in the string, then
2338 // assume we are installed in a JDK and we're done. Otherwise, check
2339 // for a JAVA_HOME environment variable and fix up the path so it
2340 // looks like libjvm.so is installed there (append a fake suffix
2341 // hotspot/libjvm.so).
2342 const char *p = buf + strlen(buf) - 1;
2343 for (int count = 0; p > buf && count < 5; ++count) {
2344 for (--p; p > buf && *p != '/'; --p)
2345 /* empty */ ;
2346 }
2347
2348 if (strncmp(p, "/jre/lib/", 9) != 0) {
2349 // Look for JAVA_HOME in the environment.
2350 char* java_home_var = ::getenv("JAVA_HOME");
2351 if (java_home_var != NULL && java_home_var[0] != 0) {
2352 char* jrelib_p;
2353 int len;
2354
2355 // Check the current module name "libjvm.so".
2356 p = strrchr(buf, '/');
2357 if (p == NULL) {
2358 return;
2359 }
2360 assert(strstr(p, "/libjvm") == p, "invalid library name");
2361
2362 rp = realpath(java_home_var, buf);
2363 if (rp == NULL) {
2364 return;
2365 }
2366
2367 // determine if this is a legacy image or modules image
2368 // modules image doesn't have "jre" subdirectory
2369 len = strlen(buf);
2370 assert(len < buflen, "Ran out of buffer room");
2371 jrelib_p = buf + len;
2372 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2373 if (0 != access(buf, F_OK)) {
2374 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2375 }
2376
2377 if (0 == access(buf, F_OK)) {
2378 // Use current module name "libjvm.so"
2379 len = strlen(buf);
2380 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2381 } else {
2382 // Go back to path of .so
2383 rp = realpath(dli_fname, buf);
2384 if (rp == NULL) {
2385 return;
2386 }
2387 }
2388 }
2389 }
2390 }
2391
2392 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2393 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2394 }
2395
2396 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2397 // no prefix required, not even "_"
2398 }
2399
2400 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2401 // no suffix required
2402 }
2403
2404 ////////////////////////////////////////////////////////////////////////////////
2405 // sun.misc.Signal support
2406
2407 static volatile jint sigint_count = 0;
2408
2409 static void UserHandler(int sig, void *siginfo, void *context) {
2410 // 4511530 - sem_post is serialized and handled by the manager thread. When
2411 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2412 // don't want to flood the manager thread with sem_post requests.
2413 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2414 return;
2415 }
2416
2417 // Ctrl-C is pressed during error reporting, likely because the error
2418 // handler fails to abort. Let VM die immediately.
2419 if (sig == SIGINT && is_error_reported()) {
2420 os::die();
2421 }
2422
2423 os::signal_notify(sig);
2424 }
2425
2426 void* os::user_handler() {
2427 return CAST_FROM_FN_PTR(void*, UserHandler);
2428 }
2429
2430 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2431 struct timespec ts;
2432 // Semaphore's are always associated with CLOCK_REALTIME
2433 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2434 // see unpackTime for discussion on overflow checking
2435 if (sec >= MAX_SECS) {
2436 ts.tv_sec += MAX_SECS;
2437 ts.tv_nsec = 0;
2438 } else {
2439 ts.tv_sec += sec;
2440 ts.tv_nsec += nsec;
2441 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2442 ts.tv_nsec -= NANOSECS_PER_SEC;
2443 ++ts.tv_sec; // note: this must be <= max_secs
2444 }
2445 }
2446
2447 return ts;
2448 }
2449
2450 extern "C" {
2451 typedef void (*sa_handler_t)(int);
2452 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2453 }
2454
2455 void* os::signal(int signal_number, void* handler) {
2456 struct sigaction sigAct, oldSigAct;
2457
2458 sigfillset(&(sigAct.sa_mask));
2459 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2460 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2461
2462 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2463 // -1 means registration failed
2464 return (void *)-1;
2465 }
2466
2467 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2468 }
2469
2470 void os::signal_raise(int signal_number) {
2471 ::raise(signal_number);
2472 }
2473
2474 // The following code is moved from os.cpp for making this
2475 // code platform specific, which it is by its very nature.
2476
2477 // Will be modified when max signal is changed to be dynamic
2478 int os::sigexitnum_pd() {
2479 return NSIG;
2480 }
2481
2482 // a counter for each possible signal value
2483 static volatile jint pending_signals[NSIG+1] = { 0 };
2484
2485 // Linux(POSIX) specific hand shaking semaphore.
2486 static sem_t sig_sem;
2487 static PosixSemaphore sr_semaphore;
2488
2489 void os::signal_init_pd() {
2490 // Initialize signal structures
2491 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2492
2493 // Initialize signal semaphore
2494 ::sem_init(&sig_sem, 0, 0);
2495 }
2496
2497 void os::signal_notify(int sig) {
2498 Atomic::inc(&pending_signals[sig]);
2499 ::sem_post(&sig_sem);
2500 }
2501
2502 static int check_pending_signals(bool wait) {
2503 Atomic::store(0, &sigint_count);
2504 for (;;) {
2505 for (int i = 0; i < NSIG + 1; i++) {
2506 jint n = pending_signals[i];
2507 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2508 return i;
2509 }
2510 }
2511 if (!wait) {
2512 return -1;
2513 }
2514 JavaThread *thread = JavaThread::current();
2515 ThreadBlockInVM tbivm(thread);
2516
2517 bool threadIsSuspended;
2518 do {
2519 thread->set_suspend_equivalent();
2520 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2521 ::sem_wait(&sig_sem);
2522
2523 // were we externally suspended while we were waiting?
2524 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2525 if (threadIsSuspended) {
2526 // The semaphore has been incremented, but while we were waiting
2527 // another thread suspended us. We don't want to continue running
2528 // while suspended because that would surprise the thread that
2529 // suspended us.
2530 ::sem_post(&sig_sem);
2531
2532 thread->java_suspend_self();
2533 }
2534 } while (threadIsSuspended);
2535 }
2536 }
2537
2538 int os::signal_lookup() {
2539 return check_pending_signals(false);
2540 }
2541
2542 int os::signal_wait() {
2543 return check_pending_signals(true);
2544 }
2545
2546 ////////////////////////////////////////////////////////////////////////////////
2547 // Virtual Memory
2548
2549 int os::vm_page_size() {
2550 // Seems redundant as all get out
2551 assert(os::Linux::page_size() != -1, "must call os::init");
2552 return os::Linux::page_size();
2553 }
2554
2555 // Solaris allocates memory by pages.
2556 int os::vm_allocation_granularity() {
2557 assert(os::Linux::page_size() != -1, "must call os::init");
2558 return os::Linux::page_size();
2559 }
2560
2561 // Rationale behind this function:
2562 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2563 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2564 // samples for JITted code. Here we create private executable mapping over the code cache
2565 // and then we can use standard (well, almost, as mapping can change) way to provide
2566 // info for the reporting script by storing timestamp and location of symbol
2567 void linux_wrap_code(char* base, size_t size) {
2568 static volatile jint cnt = 0;
2569
2570 if (!UseOprofile) {
2571 return;
2572 }
2573
2574 char buf[PATH_MAX+1];
2575 int num = Atomic::add(1, &cnt);
2576
2577 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2578 os::get_temp_directory(), os::current_process_id(), num);
2579 unlink(buf);
2580
2581 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2582
2583 if (fd != -1) {
2584 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2585 if (rv != (off_t)-1) {
2586 if (::write(fd, "", 1) == 1) {
2587 mmap(base, size,
2588 PROT_READ|PROT_WRITE|PROT_EXEC,
2589 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2590 }
2591 }
2592 ::close(fd);
2593 unlink(buf);
2594 }
2595 }
2596
2597 static bool recoverable_mmap_error(int err) {
2598 // See if the error is one we can let the caller handle. This
2599 // list of errno values comes from JBS-6843484. I can't find a
2600 // Linux man page that documents this specific set of errno
2601 // values so while this list currently matches Solaris, it may
2602 // change as we gain experience with this failure mode.
2603 switch (err) {
2604 case EBADF:
2605 case EINVAL:
2606 case ENOTSUP:
2607 // let the caller deal with these errors
2608 return true;
2609
2610 default:
2611 // Any remaining errors on this OS can cause our reserved mapping
2612 // to be lost. That can cause confusion where different data
2613 // structures think they have the same memory mapped. The worst
2614 // scenario is if both the VM and a library think they have the
2615 // same memory mapped.
2616 return false;
2617 }
2618 }
2619
2620 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2621 int err) {
2622 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2623 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2624 os::strerror(err), err);
2625 }
2626
2627 static void warn_fail_commit_memory(char* addr, size_t size,
2628 size_t alignment_hint, bool exec,
2629 int err) {
2630 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2631 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2632 alignment_hint, exec, os::strerror(err), err);
2633 }
2634
2635 // NOTE: Linux kernel does not really reserve the pages for us.
2636 // All it does is to check if there are enough free pages
2637 // left at the time of mmap(). This could be a potential
2638 // problem.
2639 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2640 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2641 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2642 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2643 if (res != (uintptr_t) MAP_FAILED) {
2644 if (UseNUMAInterleaving) {
2645 numa_make_global(addr, size);
2646 }
2647 return 0;
2648 }
2649
2650 int err = errno; // save errno from mmap() call above
2651
2652 if (!recoverable_mmap_error(err)) {
2653 warn_fail_commit_memory(addr, size, exec, err);
2654 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2655 }
2656
2657 return err;
2658 }
2659
2660 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2661 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2662 }
2663
2664 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2665 const char* mesg) {
2666 assert(mesg != NULL, "mesg must be specified");
2667 int err = os::Linux::commit_memory_impl(addr, size, exec);
2668 if (err != 0) {
2669 // the caller wants all commit errors to exit with the specified mesg:
2670 warn_fail_commit_memory(addr, size, exec, err);
2671 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2672 }
2673 }
2674
2675 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2676 #ifndef MAP_HUGETLB
2677 #define MAP_HUGETLB 0x40000
2678 #endif
2679
2680 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2681 #ifndef MADV_HUGEPAGE
2682 #define MADV_HUGEPAGE 14
2683 #endif
2684
2685 int os::Linux::commit_memory_impl(char* addr, size_t size,
2686 size_t alignment_hint, bool exec) {
2687 int err = os::Linux::commit_memory_impl(addr, size, exec);
2688 if (err == 0) {
2689 realign_memory(addr, size, alignment_hint);
2690 }
2691 return err;
2692 }
2693
2694 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2695 bool exec) {
2696 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2697 }
2698
2699 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2700 size_t alignment_hint, bool exec,
2701 const char* mesg) {
2702 assert(mesg != NULL, "mesg must be specified");
2703 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2704 if (err != 0) {
2705 // the caller wants all commit errors to exit with the specified mesg:
2706 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2707 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2708 }
2709 }
2710
2711 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2712 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2713 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2714 // be supported or the memory may already be backed by huge pages.
2715 ::madvise(addr, bytes, MADV_HUGEPAGE);
2716 }
2717 }
2718
2719 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2720 // This method works by doing an mmap over an existing mmaping and effectively discarding
2721 // the existing pages. However it won't work for SHM-based large pages that cannot be
2722 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2723 // small pages on top of the SHM segment. This method always works for small pages, so we
2724 // allow that in any case.
2725 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2726 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2727 }
2728 }
2729
2730 void os::numa_make_global(char *addr, size_t bytes) {
2731 Linux::numa_interleave_memory(addr, bytes);
2732 }
2733
2734 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2735 // bind policy to MPOL_PREFERRED for the current thread.
2736 #define USE_MPOL_PREFERRED 0
2737
2738 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2739 // To make NUMA and large pages more robust when both enabled, we need to ease
2740 // the requirements on where the memory should be allocated. MPOL_BIND is the
2741 // default policy and it will force memory to be allocated on the specified
2742 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2743 // the specified node, but will not force it. Using this policy will prevent
2744 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2745 // free large pages.
2746 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2747 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2748 }
2749
2750 bool os::numa_topology_changed() { return false; }
2751
2752 size_t os::numa_get_groups_num() {
2753 int max_node = Linux::numa_max_node();
2754 return max_node > 0 ? max_node + 1 : 1;
2755 }
2756
2757 int os::numa_get_group_id() {
2758 int cpu_id = Linux::sched_getcpu();
2759 if (cpu_id != -1) {
2760 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2761 if (lgrp_id != -1) {
2762 return lgrp_id;
2763 }
2764 }
2765 return 0;
2766 }
2767
2768 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2769 for (size_t i = 0; i < size; i++) {
2770 ids[i] = i;
2771 }
2772 return size;
2773 }
2774
2775 bool os::get_page_info(char *start, page_info* info) {
2776 return false;
2777 }
2778
2779 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2780 page_info* page_found) {
2781 return end;
2782 }
2783
2784
2785 int os::Linux::sched_getcpu_syscall(void) {
2786 unsigned int cpu = 0;
2787 int retval = -1;
2788
2789 #if defined(IA32)
2790 #ifndef SYS_getcpu
2791 #define SYS_getcpu 318
2792 #endif
2793 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2794 #elif defined(AMD64)
2795 // Unfortunately we have to bring all these macros here from vsyscall.h
2796 // to be able to compile on old linuxes.
2797 #define __NR_vgetcpu 2
2798 #define VSYSCALL_START (-10UL << 20)
2799 #define VSYSCALL_SIZE 1024
2800 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2801 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2802 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2803 retval = vgetcpu(&cpu, NULL, NULL);
2804 #endif
2805
2806 return (retval == -1) ? retval : cpu;
2807 }
2808
2809 // Something to do with the numa-aware allocator needs these symbols
2810 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2811 extern "C" JNIEXPORT void numa_error(char *where) { }
2812
2813
2814 // If we are running with libnuma version > 2, then we should
2815 // be trying to use symbols with versions 1.1
2816 // If we are running with earlier version, which did not have symbol versions,
2817 // we should use the base version.
2818 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2819 void *f = dlvsym(handle, name, "libnuma_1.1");
2820 if (f == NULL) {
2821 f = dlsym(handle, name);
2822 }
2823 return f;
2824 }
2825
2826 bool os::Linux::libnuma_init() {
2827 // sched_getcpu() should be in libc.
2828 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2829 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2830
2831 // If it's not, try a direct syscall.
2832 if (sched_getcpu() == -1) {
2833 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2834 (void*)&sched_getcpu_syscall));
2835 }
2836
2837 if (sched_getcpu() != -1) { // Does it work?
2838 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2839 if (handle != NULL) {
2840 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2841 libnuma_dlsym(handle, "numa_node_to_cpus")));
2842 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2843 libnuma_dlsym(handle, "numa_max_node")));
2844 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2845 libnuma_dlsym(handle, "numa_available")));
2846 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2847 libnuma_dlsym(handle, "numa_tonode_memory")));
2848 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2849 libnuma_dlsym(handle, "numa_interleave_memory")));
2850 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2851 libnuma_dlsym(handle, "numa_set_bind_policy")));
2852
2853
2854 if (numa_available() != -1) {
2855 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2856 // Create a cpu -> node mapping
2857 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2858 rebuild_cpu_to_node_map();
2859 return true;
2860 }
2861 }
2862 }
2863 return false;
2864 }
2865
2866 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2867 // The table is later used in get_node_by_cpu().
2868 void os::Linux::rebuild_cpu_to_node_map() {
2869 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2870 // in libnuma (possible values are starting from 16,
2871 // and continuing up with every other power of 2, but less
2872 // than the maximum number of CPUs supported by kernel), and
2873 // is a subject to change (in libnuma version 2 the requirements
2874 // are more reasonable) we'll just hardcode the number they use
2875 // in the library.
2876 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2877
2878 size_t cpu_num = os::active_processor_count();
2879 size_t cpu_map_size = NCPUS / BitsPerCLong;
2880 size_t cpu_map_valid_size =
2881 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2882
2883 cpu_to_node()->clear();
2884 cpu_to_node()->at_grow(cpu_num - 1);
2885 size_t node_num = numa_get_groups_num();
2886
2887 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2888 for (size_t i = 0; i < node_num; i++) {
2889 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2890 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2891 if (cpu_map[j] != 0) {
2892 for (size_t k = 0; k < BitsPerCLong; k++) {
2893 if (cpu_map[j] & (1UL << k)) {
2894 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2895 }
2896 }
2897 }
2898 }
2899 }
2900 }
2901 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2902 }
2903
2904 int os::Linux::get_node_by_cpu(int cpu_id) {
2905 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2906 return cpu_to_node()->at(cpu_id);
2907 }
2908 return -1;
2909 }
2910
2911 GrowableArray<int>* os::Linux::_cpu_to_node;
2912 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2913 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2914 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2915 os::Linux::numa_available_func_t os::Linux::_numa_available;
2916 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2917 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2918 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2919 unsigned long* os::Linux::_numa_all_nodes;
2920
2921 bool os::pd_uncommit_memory(char* addr, size_t size) {
2922 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2923 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2924 return res != (uintptr_t) MAP_FAILED;
2925 }
2926
2927 static address get_stack_commited_bottom(address bottom, size_t size) {
2928 address nbot = bottom;
2929 address ntop = bottom + size;
2930
2931 size_t page_sz = os::vm_page_size();
2932 unsigned pages = size / page_sz;
2933
2934 unsigned char vec[1];
2935 unsigned imin = 1, imax = pages + 1, imid;
2936 int mincore_return_value = 0;
2937
2938 assert(imin <= imax, "Unexpected page size");
2939
2940 while (imin < imax) {
2941 imid = (imax + imin) / 2;
2942 nbot = ntop - (imid * page_sz);
2943
2944 // Use a trick with mincore to check whether the page is mapped or not.
2945 // mincore sets vec to 1 if page resides in memory and to 0 if page
2946 // is swapped output but if page we are asking for is unmapped
2947 // it returns -1,ENOMEM
2948 mincore_return_value = mincore(nbot, page_sz, vec);
2949
2950 if (mincore_return_value == -1) {
2951 // Page is not mapped go up
2952 // to find first mapped page
2953 if (errno != EAGAIN) {
2954 assert(errno == ENOMEM, "Unexpected mincore errno");
2955 imax = imid;
2956 }
2957 } else {
2958 // Page is mapped go down
2959 // to find first not mapped page
2960 imin = imid + 1;
2961 }
2962 }
2963
2964 nbot = nbot + page_sz;
2965
2966 // Adjust stack bottom one page up if last checked page is not mapped
2967 if (mincore_return_value == -1) {
2968 nbot = nbot + page_sz;
2969 }
2970
2971 return nbot;
2972 }
2973
2974
2975 // Linux uses a growable mapping for the stack, and if the mapping for
2976 // the stack guard pages is not removed when we detach a thread the
2977 // stack cannot grow beyond the pages where the stack guard was
2978 // mapped. If at some point later in the process the stack expands to
2979 // that point, the Linux kernel cannot expand the stack any further
2980 // because the guard pages are in the way, and a segfault occurs.
2981 //
2982 // However, it's essential not to split the stack region by unmapping
2983 // a region (leaving a hole) that's already part of the stack mapping,
2984 // so if the stack mapping has already grown beyond the guard pages at
2985 // the time we create them, we have to truncate the stack mapping.
2986 // So, we need to know the extent of the stack mapping when
2987 // create_stack_guard_pages() is called.
2988
2989 // We only need this for stacks that are growable: at the time of
2990 // writing thread stacks don't use growable mappings (i.e. those
2991 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2992 // only applies to the main thread.
2993
2994 // If the (growable) stack mapping already extends beyond the point
2995 // where we're going to put our guard pages, truncate the mapping at
2996 // that point by munmap()ping it. This ensures that when we later
2997 // munmap() the guard pages we don't leave a hole in the stack
2998 // mapping. This only affects the main/initial thread
2999
3000 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3001 if (os::Linux::is_initial_thread()) {
3002 // As we manually grow stack up to bottom inside create_attached_thread(),
3003 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3004 // we don't need to do anything special.
3005 // Check it first, before calling heavy function.
3006 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3007 unsigned char vec[1];
3008
3009 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3010 // Fallback to slow path on all errors, including EAGAIN
3011 stack_extent = (uintptr_t) get_stack_commited_bottom(
3012 os::Linux::initial_thread_stack_bottom(),
3013 (size_t)addr - stack_extent);
3014 }
3015
3016 if (stack_extent < (uintptr_t)addr) {
3017 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3018 }
3019 }
3020
3021 return os::commit_memory(addr, size, !ExecMem);
3022 }
3023
3024 // If this is a growable mapping, remove the guard pages entirely by
3025 // munmap()ping them. If not, just call uncommit_memory(). This only
3026 // affects the main/initial thread, but guard against future OS changes
3027 // It's safe to always unmap guard pages for initial thread because we
3028 // always place it right after end of the mapped region
3029
3030 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3031 uintptr_t stack_extent, stack_base;
3032
3033 if (os::Linux::is_initial_thread()) {
3034 return ::munmap(addr, size) == 0;
3035 }
3036
3037 return os::uncommit_memory(addr, size);
3038 }
3039
3040 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3041 // at 'requested_addr'. If there are existing memory mappings at the same
3042 // location, however, they will be overwritten. If 'fixed' is false,
3043 // 'requested_addr' is only treated as a hint, the return value may or
3044 // may not start from the requested address. Unlike Linux mmap(), this
3045 // function returns NULL to indicate failure.
3046 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3047 char * addr;
3048 int flags;
3049
3050 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3051 if (fixed) {
3052 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3053 flags |= MAP_FIXED;
3054 }
3055
3056 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3057 // touch an uncommitted page. Otherwise, the read/write might
3058 // succeed if we have enough swap space to back the physical page.
3059 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3060 flags, -1, 0);
3061
3062 return addr == MAP_FAILED ? NULL : addr;
3063 }
3064
3065 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3066 // (req_addr != NULL) or with a given alignment.
3067 // - bytes shall be a multiple of alignment.
3068 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3069 // - alignment sets the alignment at which memory shall be allocated.
3070 // It must be a multiple of allocation granularity.
3071 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3072 // req_addr or NULL.
3073 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3074
3075 size_t extra_size = bytes;
3076 if (req_addr == NULL && alignment > 0) {
3077 extra_size += alignment;
3078 }
3079
3080 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3081 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3082 -1, 0);
3083 if (start == MAP_FAILED) {
3084 start = NULL;
3085 } else {
3086 if (req_addr != NULL) {
3087 if (start != req_addr) {
3088 ::munmap(start, extra_size);
3089 start = NULL;
3090 }
3091 } else {
3092 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3093 char* const end_aligned = start_aligned + bytes;
3094 char* const end = start + extra_size;
3095 if (start_aligned > start) {
3096 ::munmap(start, start_aligned - start);
3097 }
3098 if (end_aligned < end) {
3099 ::munmap(end_aligned, end - end_aligned);
3100 }
3101 start = start_aligned;
3102 }
3103 }
3104 return start;
3105 }
3106
3107 static int anon_munmap(char * addr, size_t size) {
3108 return ::munmap(addr, size) == 0;
3109 }
3110
3111 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3112 size_t alignment_hint) {
3113 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3114 }
3115
3116 bool os::pd_release_memory(char* addr, size_t size) {
3117 return anon_munmap(addr, size);
3118 }
3119
3120 static bool linux_mprotect(char* addr, size_t size, int prot) {
3121 // Linux wants the mprotect address argument to be page aligned.
3122 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3123
3124 // According to SUSv3, mprotect() should only be used with mappings
3125 // established by mmap(), and mmap() always maps whole pages. Unaligned
3126 // 'addr' likely indicates problem in the VM (e.g. trying to change
3127 // protection of malloc'ed or statically allocated memory). Check the
3128 // caller if you hit this assert.
3129 assert(addr == bottom, "sanity check");
3130
3131 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3132 return ::mprotect(bottom, size, prot) == 0;
3133 }
3134
3135 // Set protections specified
3136 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3137 bool is_committed) {
3138 unsigned int p = 0;
3139 switch (prot) {
3140 case MEM_PROT_NONE: p = PROT_NONE; break;
3141 case MEM_PROT_READ: p = PROT_READ; break;
3142 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3143 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3144 default:
3145 ShouldNotReachHere();
3146 }
3147 // is_committed is unused.
3148 return linux_mprotect(addr, bytes, p);
3149 }
3150
3151 bool os::guard_memory(char* addr, size_t size) {
3152 return linux_mprotect(addr, size, PROT_NONE);
3153 }
3154
3155 bool os::unguard_memory(char* addr, size_t size) {
3156 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3157 }
3158
3159 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3160 size_t page_size) {
3161 bool result = false;
3162 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3163 MAP_ANONYMOUS|MAP_PRIVATE,
3164 -1, 0);
3165 if (p != MAP_FAILED) {
3166 void *aligned_p = align_ptr_up(p, page_size);
3167
3168 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3169
3170 munmap(p, page_size * 2);
3171 }
3172
3173 if (warn && !result) {
3174 warning("TransparentHugePages is not supported by the operating system.");
3175 }
3176
3177 return result;
3178 }
3179
3180 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3181 bool result = false;
3182 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3183 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3184 -1, 0);
3185
3186 if (p != MAP_FAILED) {
3187 // We don't know if this really is a huge page or not.
3188 FILE *fp = fopen("/proc/self/maps", "r");
3189 if (fp) {
3190 while (!feof(fp)) {
3191 char chars[257];
3192 long x = 0;
3193 if (fgets(chars, sizeof(chars), fp)) {
3194 if (sscanf(chars, "%lx-%*x", &x) == 1
3195 && x == (long)p) {
3196 if (strstr (chars, "hugepage")) {
3197 result = true;
3198 break;
3199 }
3200 }
3201 }
3202 }
3203 fclose(fp);
3204 }
3205 munmap(p, page_size);
3206 }
3207
3208 if (warn && !result) {
3209 warning("HugeTLBFS is not supported by the operating system.");
3210 }
3211
3212 return result;
3213 }
3214
3215 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3216 //
3217 // From the coredump_filter documentation:
3218 //
3219 // - (bit 0) anonymous private memory
3220 // - (bit 1) anonymous shared memory
3221 // - (bit 2) file-backed private memory
3222 // - (bit 3) file-backed shared memory
3223 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3224 // effective only if the bit 2 is cleared)
3225 // - (bit 5) hugetlb private memory
3226 // - (bit 6) hugetlb shared memory
3227 //
3228 static void set_coredump_filter(void) {
3229 FILE *f;
3230 long cdm;
3231
3232 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3233 return;
3234 }
3235
3236 if (fscanf(f, "%lx", &cdm) != 1) {
3237 fclose(f);
3238 return;
3239 }
3240
3241 rewind(f);
3242
3243 if ((cdm & LARGEPAGES_BIT) == 0) {
3244 cdm |= LARGEPAGES_BIT;
3245 fprintf(f, "%#lx", cdm);
3246 }
3247
3248 fclose(f);
3249 }
3250
3251 // Large page support
3252
3253 static size_t _large_page_size = 0;
3254
3255 size_t os::Linux::find_large_page_size() {
3256 size_t large_page_size = 0;
3257
3258 // large_page_size on Linux is used to round up heap size. x86 uses either
3259 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3260 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3261 // page as large as 256M.
3262 //
3263 // Here we try to figure out page size by parsing /proc/meminfo and looking
3264 // for a line with the following format:
3265 // Hugepagesize: 2048 kB
3266 //
3267 // If we can't determine the value (e.g. /proc is not mounted, or the text
3268 // format has been changed), we'll use the largest page size supported by
3269 // the processor.
3270
3271 #ifndef ZERO
3272 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3273 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M);
3274 #endif // ZERO
3275
3276 FILE *fp = fopen("/proc/meminfo", "r");
3277 if (fp) {
3278 while (!feof(fp)) {
3279 int x = 0;
3280 char buf[16];
3281 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3282 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3283 large_page_size = x * K;
3284 break;
3285 }
3286 } else {
3287 // skip to next line
3288 for (;;) {
3289 int ch = fgetc(fp);
3290 if (ch == EOF || ch == (int)'\n') break;
3291 }
3292 }
3293 }
3294 fclose(fp);
3295 }
3296
3297 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3298 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3299 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3300 proper_unit_for_byte_size(large_page_size));
3301 }
3302
3303 return large_page_size;
3304 }
3305
3306 size_t os::Linux::setup_large_page_size() {
3307 _large_page_size = Linux::find_large_page_size();
3308 const size_t default_page_size = (size_t)Linux::page_size();
3309 if (_large_page_size > default_page_size) {
3310 _page_sizes[0] = _large_page_size;
3311 _page_sizes[1] = default_page_size;
3312 _page_sizes[2] = 0;
3313 }
3314
3315 return _large_page_size;
3316 }
3317
3318 bool os::Linux::setup_large_page_type(size_t page_size) {
3319 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3320 FLAG_IS_DEFAULT(UseSHM) &&
3321 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3322
3323 // The type of large pages has not been specified by the user.
3324
3325 // Try UseHugeTLBFS and then UseSHM.
3326 UseHugeTLBFS = UseSHM = true;
3327
3328 // Don't try UseTransparentHugePages since there are known
3329 // performance issues with it turned on. This might change in the future.
3330 UseTransparentHugePages = false;
3331 }
3332
3333 if (UseTransparentHugePages) {
3334 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3335 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3336 UseHugeTLBFS = false;
3337 UseSHM = false;
3338 return true;
3339 }
3340 UseTransparentHugePages = false;
3341 }
3342
3343 if (UseHugeTLBFS) {
3344 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3345 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3346 UseSHM = false;
3347 return true;
3348 }
3349 UseHugeTLBFS = false;
3350 }
3351
3352 return UseSHM;
3353 }
3354
3355 void os::large_page_init() {
3356 if (!UseLargePages &&
3357 !UseTransparentHugePages &&
3358 !UseHugeTLBFS &&
3359 !UseSHM) {
3360 // Not using large pages.
3361 return;
3362 }
3363
3364 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3365 // The user explicitly turned off large pages.
3366 // Ignore the rest of the large pages flags.
3367 UseTransparentHugePages = false;
3368 UseHugeTLBFS = false;
3369 UseSHM = false;
3370 return;
3371 }
3372
3373 size_t large_page_size = Linux::setup_large_page_size();
3374 UseLargePages = Linux::setup_large_page_type(large_page_size);
3375
3376 set_coredump_filter();
3377 }
3378
3379 #ifndef SHM_HUGETLB
3380 #define SHM_HUGETLB 04000
3381 #endif
3382
3383 #define shm_warning_format(format, ...) \
3384 do { \
3385 if (UseLargePages && \
3386 (!FLAG_IS_DEFAULT(UseLargePages) || \
3387 !FLAG_IS_DEFAULT(UseSHM) || \
3388 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3389 warning(format, __VA_ARGS__); \
3390 } \
3391 } while (0)
3392
3393 #define shm_warning(str) shm_warning_format("%s", str)
3394
3395 #define shm_warning_with_errno(str) \
3396 do { \
3397 int err = errno; \
3398 shm_warning_format(str " (error = %d)", err); \
3399 } while (0)
3400
3401 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3402 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3403
3404 if (!is_size_aligned(alignment, SHMLBA)) {
3405 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3406 return NULL;
3407 }
3408
3409 // To ensure that we get 'alignment' aligned memory from shmat,
3410 // we pre-reserve aligned virtual memory and then attach to that.
3411
3412 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3413 if (pre_reserved_addr == NULL) {
3414 // Couldn't pre-reserve aligned memory.
3415 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3416 return NULL;
3417 }
3418
3419 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3420 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3421
3422 if ((intptr_t)addr == -1) {
3423 int err = errno;
3424 shm_warning_with_errno("Failed to attach shared memory.");
3425
3426 assert(err != EACCES, "Unexpected error");
3427 assert(err != EIDRM, "Unexpected error");
3428 assert(err != EINVAL, "Unexpected error");
3429
3430 // Since we don't know if the kernel unmapped the pre-reserved memory area
3431 // we can't unmap it, since that would potentially unmap memory that was
3432 // mapped from other threads.
3433 return NULL;
3434 }
3435
3436 return addr;
3437 }
3438
3439 static char* shmat_at_address(int shmid, char* req_addr) {
3440 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3441 assert(false, "Requested address needs to be SHMLBA aligned");
3442 return NULL;
3443 }
3444
3445 char* addr = (char*)shmat(shmid, req_addr, 0);
3446
3447 if ((intptr_t)addr == -1) {
3448 shm_warning_with_errno("Failed to attach shared memory.");
3449 return NULL;
3450 }
3451
3452 return addr;
3453 }
3454
3455 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3456 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3457 if (req_addr != NULL) {
3458 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3459 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3460 return shmat_at_address(shmid, req_addr);
3461 }
3462
3463 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3464 // return large page size aligned memory addresses when req_addr == NULL.
3465 // However, if the alignment is larger than the large page size, we have
3466 // to manually ensure that the memory returned is 'alignment' aligned.
3467 if (alignment > os::large_page_size()) {
3468 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3469 return shmat_with_alignment(shmid, bytes, alignment);
3470 } else {
3471 return shmat_at_address(shmid, NULL);
3472 }
3473 }
3474
3475 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3476 char* req_addr, bool exec) {
3477 // "exec" is passed in but not used. Creating the shared image for
3478 // the code cache doesn't have an SHM_X executable permission to check.
3479 assert(UseLargePages && UseSHM, "only for SHM large pages");
3480 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3481 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3482
3483 if (!is_size_aligned(bytes, os::large_page_size())) {
3484 return NULL; // Fallback to small pages.
3485 }
3486
3487 // Create a large shared memory region to attach to based on size.
3488 // Currently, size is the total size of the heap.
3489 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3490 if (shmid == -1) {
3491 // Possible reasons for shmget failure:
3492 // 1. shmmax is too small for Java heap.
3493 // > check shmmax value: cat /proc/sys/kernel/shmmax
3494 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3495 // 2. not enough large page memory.
3496 // > check available large pages: cat /proc/meminfo
3497 // > increase amount of large pages:
3498 // echo new_value > /proc/sys/vm/nr_hugepages
3499 // Note 1: different Linux may use different name for this property,
3500 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3501 // Note 2: it's possible there's enough physical memory available but
3502 // they are so fragmented after a long run that they can't
3503 // coalesce into large pages. Try to reserve large pages when
3504 // the system is still "fresh".
3505 shm_warning_with_errno("Failed to reserve shared memory.");
3506 return NULL;
3507 }
3508
3509 // Attach to the region.
3510 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3511
3512 // Remove shmid. If shmat() is successful, the actual shared memory segment
3513 // will be deleted when it's detached by shmdt() or when the process
3514 // terminates. If shmat() is not successful this will remove the shared
3515 // segment immediately.
3516 shmctl(shmid, IPC_RMID, NULL);
3517
3518 return addr;
3519 }
3520
3521 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3522 int error) {
3523 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3524
3525 bool warn_on_failure = UseLargePages &&
3526 (!FLAG_IS_DEFAULT(UseLargePages) ||
3527 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3528 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3529
3530 if (warn_on_failure) {
3531 char msg[128];
3532 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3533 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3534 warning("%s", msg);
3535 }
3536 }
3537
3538 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3539 char* req_addr,
3540 bool exec) {
3541 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3542 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3543 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3544
3545 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3546 char* addr = (char*)::mmap(req_addr, bytes, prot,
3547 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3548 -1, 0);
3549
3550 if (addr == MAP_FAILED) {
3551 warn_on_large_pages_failure(req_addr, bytes, errno);
3552 return NULL;
3553 }
3554
3555 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3556
3557 return addr;
3558 }
3559
3560 // Reserve memory using mmap(MAP_HUGETLB).
3561 // - bytes shall be a multiple of alignment.
3562 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3563 // - alignment sets the alignment at which memory shall be allocated.
3564 // It must be a multiple of allocation granularity.
3565 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3566 // req_addr or NULL.
3567 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3568 size_t alignment,
3569 char* req_addr,
3570 bool exec) {
3571 size_t large_page_size = os::large_page_size();
3572 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3573
3574 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3575 assert(is_size_aligned(bytes, alignment), "Must be");
3576
3577 // First reserve - but not commit - the address range in small pages.
3578 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3579
3580 if (start == NULL) {
3581 return NULL;
3582 }
3583
3584 assert(is_ptr_aligned(start, alignment), "Must be");
3585
3586 char* end = start + bytes;
3587
3588 // Find the regions of the allocated chunk that can be promoted to large pages.
3589 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3590 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3591
3592 size_t lp_bytes = lp_end - lp_start;
3593
3594 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3595
3596 if (lp_bytes == 0) {
3597 // The mapped region doesn't even span the start and the end of a large page.
3598 // Fall back to allocate a non-special area.
3599 ::munmap(start, end - start);
3600 return NULL;
3601 }
3602
3603 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3604
3605 void* result;
3606
3607 // Commit small-paged leading area.
3608 if (start != lp_start) {
3609 result = ::mmap(start, lp_start - start, prot,
3610 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3611 -1, 0);
3612 if (result == MAP_FAILED) {
3613 ::munmap(lp_start, end - lp_start);
3614 return NULL;
3615 }
3616 }
3617
3618 // Commit large-paged area.
3619 result = ::mmap(lp_start, lp_bytes, prot,
3620 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3621 -1, 0);
3622 if (result == MAP_FAILED) {
3623 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3624 // If the mmap above fails, the large pages region will be unmapped and we
3625 // have regions before and after with small pages. Release these regions.
3626 //
3627 // | mapped | unmapped | mapped |
3628 // ^ ^ ^ ^
3629 // start lp_start lp_end end
3630 //
3631 ::munmap(start, lp_start - start);
3632 ::munmap(lp_end, end - lp_end);
3633 return NULL;
3634 }
3635
3636 // Commit small-paged trailing area.
3637 if (lp_end != end) {
3638 result = ::mmap(lp_end, end - lp_end, prot,
3639 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3640 -1, 0);
3641 if (result == MAP_FAILED) {
3642 ::munmap(start, lp_end - start);
3643 return NULL;
3644 }
3645 }
3646
3647 return start;
3648 }
3649
3650 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3651 size_t alignment,
3652 char* req_addr,
3653 bool exec) {
3654 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3655 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3656 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3657 assert(is_power_of_2(os::large_page_size()), "Must be");
3658 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3659
3660 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3661 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3662 } else {
3663 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3664 }
3665 }
3666
3667 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3668 char* req_addr, bool exec) {
3669 assert(UseLargePages, "only for large pages");
3670
3671 char* addr;
3672 if (UseSHM) {
3673 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3674 } else {
3675 assert(UseHugeTLBFS, "must be");
3676 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3677 }
3678
3679 if (addr != NULL) {
3680 if (UseNUMAInterleaving) {
3681 numa_make_global(addr, bytes);
3682 }
3683
3684 // The memory is committed
3685 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3686 }
3687
3688 return addr;
3689 }
3690
3691 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3692 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3693 return shmdt(base) == 0;
3694 }
3695
3696 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3697 return pd_release_memory(base, bytes);
3698 }
3699
3700 bool os::release_memory_special(char* base, size_t bytes) {
3701 bool res;
3702 if (MemTracker::tracking_level() > NMT_minimal) {
3703 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3704 res = os::Linux::release_memory_special_impl(base, bytes);
3705 if (res) {
3706 tkr.record((address)base, bytes);
3707 }
3708
3709 } else {
3710 res = os::Linux::release_memory_special_impl(base, bytes);
3711 }
3712 return res;
3713 }
3714
3715 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3716 assert(UseLargePages, "only for large pages");
3717 bool res;
3718
3719 if (UseSHM) {
3720 res = os::Linux::release_memory_special_shm(base, bytes);
3721 } else {
3722 assert(UseHugeTLBFS, "must be");
3723 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3724 }
3725 return res;
3726 }
3727
3728 size_t os::large_page_size() {
3729 return _large_page_size;
3730 }
3731
3732 // With SysV SHM the entire memory region must be allocated as shared
3733 // memory.
3734 // HugeTLBFS allows application to commit large page memory on demand.
3735 // However, when committing memory with HugeTLBFS fails, the region
3736 // that was supposed to be committed will lose the old reservation
3737 // and allow other threads to steal that memory region. Because of this
3738 // behavior we can't commit HugeTLBFS memory.
3739 bool os::can_commit_large_page_memory() {
3740 return UseTransparentHugePages;
3741 }
3742
3743 bool os::can_execute_large_page_memory() {
3744 return UseTransparentHugePages || UseHugeTLBFS;
3745 }
3746
3747 // Reserve memory at an arbitrary address, only if that area is
3748 // available (and not reserved for something else).
3749
3750 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3751 const int max_tries = 10;
3752 char* base[max_tries];
3753 size_t size[max_tries];
3754 const size_t gap = 0x000000;
3755
3756 // Assert only that the size is a multiple of the page size, since
3757 // that's all that mmap requires, and since that's all we really know
3758 // about at this low abstraction level. If we need higher alignment,
3759 // we can either pass an alignment to this method or verify alignment
3760 // in one of the methods further up the call chain. See bug 5044738.
3761 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3762
3763 // Repeatedly allocate blocks until the block is allocated at the
3764 // right spot.
3765
3766 // Linux mmap allows caller to pass an address as hint; give it a try first,
3767 // if kernel honors the hint then we can return immediately.
3768 char * addr = anon_mmap(requested_addr, bytes, false);
3769 if (addr == requested_addr) {
3770 return requested_addr;
3771 }
3772
3773 if (addr != NULL) {
3774 // mmap() is successful but it fails to reserve at the requested address
3775 anon_munmap(addr, bytes);
3776 }
3777
3778 int i;
3779 for (i = 0; i < max_tries; ++i) {
3780 base[i] = reserve_memory(bytes);
3781
3782 if (base[i] != NULL) {
3783 // Is this the block we wanted?
3784 if (base[i] == requested_addr) {
3785 size[i] = bytes;
3786 break;
3787 }
3788
3789 // Does this overlap the block we wanted? Give back the overlapped
3790 // parts and try again.
3791
3792 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3793 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3794 unmap_memory(base[i], top_overlap);
3795 base[i] += top_overlap;
3796 size[i] = bytes - top_overlap;
3797 } else {
3798 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3799 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3800 unmap_memory(requested_addr, bottom_overlap);
3801 size[i] = bytes - bottom_overlap;
3802 } else {
3803 size[i] = bytes;
3804 }
3805 }
3806 }
3807 }
3808
3809 // Give back the unused reserved pieces.
3810
3811 for (int j = 0; j < i; ++j) {
3812 if (base[j] != NULL) {
3813 unmap_memory(base[j], size[j]);
3814 }
3815 }
3816
3817 if (i < max_tries) {
3818 return requested_addr;
3819 } else {
3820 return NULL;
3821 }
3822 }
3823
3824 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3825 return ::read(fd, buf, nBytes);
3826 }
3827
3828 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3829 return ::pread(fd, buf, nBytes, offset);
3830 }
3831
3832 // Short sleep, direct OS call.
3833 //
3834 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3835 // sched_yield(2) will actually give up the CPU:
3836 //
3837 // * Alone on this pariticular CPU, keeps running.
3838 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3839 // (pre 2.6.39).
3840 //
3841 // So calling this with 0 is an alternative.
3842 //
3843 void os::naked_short_sleep(jlong ms) {
3844 struct timespec req;
3845
3846 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3847 req.tv_sec = 0;
3848 if (ms > 0) {
3849 req.tv_nsec = (ms % 1000) * 1000000;
3850 } else {
3851 req.tv_nsec = 1;
3852 }
3853
3854 nanosleep(&req, NULL);
3855
3856 return;
3857 }
3858
3859 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3860 void os::infinite_sleep() {
3861 while (true) { // sleep forever ...
3862 ::sleep(100); // ... 100 seconds at a time
3863 }
3864 }
3865
3866 // Used to convert frequent JVM_Yield() to nops
3867 bool os::dont_yield() {
3868 return DontYieldALot;
3869 }
3870
3871 void os::naked_yield() {
3872 sched_yield();
3873 }
3874
3875 ////////////////////////////////////////////////////////////////////////////////
3876 // thread priority support
3877
3878 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3879 // only supports dynamic priority, static priority must be zero. For real-time
3880 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3881 // However, for large multi-threaded applications, SCHED_RR is not only slower
3882 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3883 // of 5 runs - Sep 2005).
3884 //
3885 // The following code actually changes the niceness of kernel-thread/LWP. It
3886 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3887 // not the entire user process, and user level threads are 1:1 mapped to kernel
3888 // threads. It has always been the case, but could change in the future. For
3889 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3890 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3891
3892 int os::java_to_os_priority[CriticalPriority + 1] = {
3893 19, // 0 Entry should never be used
3894
3895 4, // 1 MinPriority
3896 3, // 2
3897 2, // 3
3898
3899 1, // 4
3900 0, // 5 NormPriority
3901 -1, // 6
3902
3903 -2, // 7
3904 -3, // 8
3905 -4, // 9 NearMaxPriority
3906
3907 -5, // 10 MaxPriority
3908
3909 -5 // 11 CriticalPriority
3910 };
3911
3912 static int prio_init() {
3913 if (ThreadPriorityPolicy == 1) {
3914 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3915 // if effective uid is not root. Perhaps, a more elegant way of doing
3916 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3917 if (geteuid() != 0) {
3918 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3919 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3920 }
3921 ThreadPriorityPolicy = 0;
3922 }
3923 }
3924 if (UseCriticalJavaThreadPriority) {
3925 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3926 }
3927 return 0;
3928 }
3929
3930 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3931 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3932
3933 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3934 return (ret == 0) ? OS_OK : OS_ERR;
3935 }
3936
3937 OSReturn os::get_native_priority(const Thread* const thread,
3938 int *priority_ptr) {
3939 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3940 *priority_ptr = java_to_os_priority[NormPriority];
3941 return OS_OK;
3942 }
3943
3944 errno = 0;
3945 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3946 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3947 }
3948
3949 // Hint to the underlying OS that a task switch would not be good.
3950 // Void return because it's a hint and can fail.
3951 void os::hint_no_preempt() {}
3952
3953 ////////////////////////////////////////////////////////////////////////////////
3954 // suspend/resume support
3955
3956 // the low-level signal-based suspend/resume support is a remnant from the
3957 // old VM-suspension that used to be for java-suspension, safepoints etc,
3958 // within hotspot. Now there is a single use-case for this:
3959 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3960 // that runs in the watcher thread.
3961 // The remaining code is greatly simplified from the more general suspension
3962 // code that used to be used.
3963 //
3964 // The protocol is quite simple:
3965 // - suspend:
3966 // - sends a signal to the target thread
3967 // - polls the suspend state of the osthread using a yield loop
3968 // - target thread signal handler (SR_handler) sets suspend state
3969 // and blocks in sigsuspend until continued
3970 // - resume:
3971 // - sets target osthread state to continue
3972 // - sends signal to end the sigsuspend loop in the SR_handler
3973 //
3974 // Note that the SR_lock plays no role in this suspend/resume protocol.
3975
3976 static void resume_clear_context(OSThread *osthread) {
3977 osthread->set_ucontext(NULL);
3978 osthread->set_siginfo(NULL);
3979 }
3980
3981 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
3982 ucontext_t* context) {
3983 osthread->set_ucontext(context);
3984 osthread->set_siginfo(siginfo);
3985 }
3986
3987 // Handler function invoked when a thread's execution is suspended or
3988 // resumed. We have to be careful that only async-safe functions are
3989 // called here (Note: most pthread functions are not async safe and
3990 // should be avoided.)
3991 //
3992 // Note: sigwait() is a more natural fit than sigsuspend() from an
3993 // interface point of view, but sigwait() prevents the signal hander
3994 // from being run. libpthread would get very confused by not having
3995 // its signal handlers run and prevents sigwait()'s use with the
3996 // mutex granting granting signal.
3997 //
3998 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3999 //
4000 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4001 // Save and restore errno to avoid confusing native code with EINTR
4002 // after sigsuspend.
4003 int old_errno = errno;
4004
4005 Thread* thread = Thread::current_or_null_safe();
4006 assert(thread != NULL, "Missing current thread in SR_handler");
4007
4008 // On some systems we have seen signal delivery get "stuck" until the signal
4009 // mask is changed as part of thread termination. Check the current thread
4010 // has not already terminated (via SR_lock()) - else the following assertion
4011 // will fail because the thread is no longer a JavaThread as the ~JavaThread
4012 // destructor has completed.
4013
4014 if (thread->SR_lock() == NULL)
4015 return;
4016
4017 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4018
4019 OSThread* osthread = thread->osthread();
4020
4021 os::SuspendResume::State current = osthread->sr.state();
4022 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4023 suspend_save_context(osthread, siginfo, context);
4024
4025 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4026 os::SuspendResume::State state = osthread->sr.suspended();
4027 if (state == os::SuspendResume::SR_SUSPENDED) {
4028 sigset_t suspend_set; // signals for sigsuspend()
4029 sigemptyset(&suspend_set);
4030 // get current set of blocked signals and unblock resume signal
4031 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4032 sigdelset(&suspend_set, SR_signum);
4033
4034 sr_semaphore.signal();
4035 // wait here until we are resumed
4036 while (1) {
4037 sigsuspend(&suspend_set);
4038
4039 os::SuspendResume::State result = osthread->sr.running();
4040 if (result == os::SuspendResume::SR_RUNNING) {
4041 sr_semaphore.signal();
4042 break;
4043 }
4044 }
4045
4046 } else if (state == os::SuspendResume::SR_RUNNING) {
4047 // request was cancelled, continue
4048 } else {
4049 ShouldNotReachHere();
4050 }
4051
4052 resume_clear_context(osthread);
4053 } else if (current == os::SuspendResume::SR_RUNNING) {
4054 // request was cancelled, continue
4055 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4056 // ignore
4057 } else {
4058 // ignore
4059 }
4060
4061 errno = old_errno;
4062 }
4063
4064 static int SR_initialize() {
4065 struct sigaction act;
4066 char *s;
4067
4068 // Get signal number to use for suspend/resume
4069 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4070 int sig = ::strtol(s, 0, 10);
4071 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
4072 sig < NSIG) { // Must be legal signal and fit into sigflags[].
4073 SR_signum = sig;
4074 } else {
4075 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
4076 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
4077 }
4078 }
4079
4080 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4081 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4082
4083 sigemptyset(&SR_sigset);
4084 sigaddset(&SR_sigset, SR_signum);
4085
4086 // Set up signal handler for suspend/resume
4087 act.sa_flags = SA_RESTART|SA_SIGINFO;
4088 act.sa_handler = (void (*)(int)) SR_handler;
4089
4090 // SR_signum is blocked by default.
4091 // 4528190 - We also need to block pthread restart signal (32 on all
4092 // supported Linux platforms). Note that LinuxThreads need to block
4093 // this signal for all threads to work properly. So we don't have
4094 // to use hard-coded signal number when setting up the mask.
4095 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4096
4097 if (sigaction(SR_signum, &act, 0) == -1) {
4098 return -1;
4099 }
4100
4101 // Save signal flag
4102 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4103 return 0;
4104 }
4105
4106 static int sr_notify(OSThread* osthread) {
4107 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4108 assert_status(status == 0, status, "pthread_kill");
4109 return status;
4110 }
4111
4112 // "Randomly" selected value for how long we want to spin
4113 // before bailing out on suspending a thread, also how often
4114 // we send a signal to a thread we want to resume
4115 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4116 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4117
4118 // returns true on success and false on error - really an error is fatal
4119 // but this seems the normal response to library errors
4120 static bool do_suspend(OSThread* osthread) {
4121 assert(osthread->sr.is_running(), "thread should be running");
4122 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4123
4124 // mark as suspended and send signal
4125 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4126 // failed to switch, state wasn't running?
4127 ShouldNotReachHere();
4128 return false;
4129 }
4130
4131 if (sr_notify(osthread) != 0) {
4132 ShouldNotReachHere();
4133 }
4134
4135 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4136 while (true) {
4137 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4138 break;
4139 } else {
4140 // timeout
4141 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4142 if (cancelled == os::SuspendResume::SR_RUNNING) {
4143 return false;
4144 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4145 // make sure that we consume the signal on the semaphore as well
4146 sr_semaphore.wait();
4147 break;
4148 } else {
4149 ShouldNotReachHere();
4150 return false;
4151 }
4152 }
4153 }
4154
4155 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4156 return true;
4157 }
4158
4159 static void do_resume(OSThread* osthread) {
4160 assert(osthread->sr.is_suspended(), "thread should be suspended");
4161 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4162
4163 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4164 // failed to switch to WAKEUP_REQUEST
4165 ShouldNotReachHere();
4166 return;
4167 }
4168
4169 while (true) {
4170 if (sr_notify(osthread) == 0) {
4171 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4172 if (osthread->sr.is_running()) {
4173 return;
4174 }
4175 }
4176 } else {
4177 ShouldNotReachHere();
4178 }
4179 }
4180
4181 guarantee(osthread->sr.is_running(), "Must be running!");
4182 }
4183
4184 ///////////////////////////////////////////////////////////////////////////////////
4185 // signal handling (except suspend/resume)
4186
4187 // This routine may be used by user applications as a "hook" to catch signals.
4188 // The user-defined signal handler must pass unrecognized signals to this
4189 // routine, and if it returns true (non-zero), then the signal handler must
4190 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4191 // routine will never retun false (zero), but instead will execute a VM panic
4192 // routine kill the process.
4193 //
4194 // If this routine returns false, it is OK to call it again. This allows
4195 // the user-defined signal handler to perform checks either before or after
4196 // the VM performs its own checks. Naturally, the user code would be making
4197 // a serious error if it tried to handle an exception (such as a null check
4198 // or breakpoint) that the VM was generating for its own correct operation.
4199 //
4200 // This routine may recognize any of the following kinds of signals:
4201 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4202 // It should be consulted by handlers for any of those signals.
4203 //
4204 // The caller of this routine must pass in the three arguments supplied
4205 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4206 // field of the structure passed to sigaction(). This routine assumes that
4207 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4208 //
4209 // Note that the VM will print warnings if it detects conflicting signal
4210 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4211 //
4212 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4213 siginfo_t* siginfo,
4214 void* ucontext,
4215 int abort_if_unrecognized);
4216
4217 void signalHandler(int sig, siginfo_t* info, void* uc) {
4218 assert(info != NULL && uc != NULL, "it must be old kernel");
4219 int orig_errno = errno; // Preserve errno value over signal handler.
4220 JVM_handle_linux_signal(sig, info, uc, true);
4221 errno = orig_errno;
4222 }
4223
4224
4225 // This boolean allows users to forward their own non-matching signals
4226 // to JVM_handle_linux_signal, harmlessly.
4227 bool os::Linux::signal_handlers_are_installed = false;
4228
4229 // For signal-chaining
4230 struct sigaction sigact[NSIG];
4231 uint64_t sigs = 0;
4232 #if (64 < NSIG-1)
4233 #error "Not all signals can be encoded in sigs. Adapt its type!"
4234 #endif
4235 bool os::Linux::libjsig_is_loaded = false;
4236 typedef struct sigaction *(*get_signal_t)(int);
4237 get_signal_t os::Linux::get_signal_action = NULL;
4238
4239 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4240 struct sigaction *actp = NULL;
4241
4242 if (libjsig_is_loaded) {
4243 // Retrieve the old signal handler from libjsig
4244 actp = (*get_signal_action)(sig);
4245 }
4246 if (actp == NULL) {
4247 // Retrieve the preinstalled signal handler from jvm
4248 actp = get_preinstalled_handler(sig);
4249 }
4250
4251 return actp;
4252 }
4253
4254 static bool call_chained_handler(struct sigaction *actp, int sig,
4255 siginfo_t *siginfo, void *context) {
4256 // Call the old signal handler
4257 if (actp->sa_handler == SIG_DFL) {
4258 // It's more reasonable to let jvm treat it as an unexpected exception
4259 // instead of taking the default action.
4260 return false;
4261 } else if (actp->sa_handler != SIG_IGN) {
4262 if ((actp->sa_flags & SA_NODEFER) == 0) {
4263 // automaticlly block the signal
4264 sigaddset(&(actp->sa_mask), sig);
4265 }
4266
4267 sa_handler_t hand = NULL;
4268 sa_sigaction_t sa = NULL;
4269 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4270 // retrieve the chained handler
4271 if (siginfo_flag_set) {
4272 sa = actp->sa_sigaction;
4273 } else {
4274 hand = actp->sa_handler;
4275 }
4276
4277 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4278 actp->sa_handler = SIG_DFL;
4279 }
4280
4281 // try to honor the signal mask
4282 sigset_t oset;
4283 sigemptyset(&oset);
4284 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4285
4286 // call into the chained handler
4287 if (siginfo_flag_set) {
4288 (*sa)(sig, siginfo, context);
4289 } else {
4290 (*hand)(sig);
4291 }
4292
4293 // restore the signal mask
4294 pthread_sigmask(SIG_SETMASK, &oset, NULL);
4295 }
4296 // Tell jvm's signal handler the signal is taken care of.
4297 return true;
4298 }
4299
4300 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4301 bool chained = false;
4302 // signal-chaining
4303 if (UseSignalChaining) {
4304 struct sigaction *actp = get_chained_signal_action(sig);
4305 if (actp != NULL) {
4306 chained = call_chained_handler(actp, sig, siginfo, context);
4307 }
4308 }
4309 return chained;
4310 }
4311
4312 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4313 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4314 return &sigact[sig];
4315 }
4316 return NULL;
4317 }
4318
4319 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4320 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4321 sigact[sig] = oldAct;
4322 sigs |= (uint64_t)1 << (sig-1);
4323 }
4324
4325 // for diagnostic
4326 int sigflags[NSIG];
4327
4328 int os::Linux::get_our_sigflags(int sig) {
4329 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4330 return sigflags[sig];
4331 }
4332
4333 void os::Linux::set_our_sigflags(int sig, int flags) {
4334 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4335 if (sig > 0 && sig < NSIG) {
4336 sigflags[sig] = flags;
4337 }
4338 }
4339
4340 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4341 // Check for overwrite.
4342 struct sigaction oldAct;
4343 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4344
4345 void* oldhand = oldAct.sa_sigaction
4346 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4347 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4348 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4349 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4350 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4351 if (AllowUserSignalHandlers || !set_installed) {
4352 // Do not overwrite; user takes responsibility to forward to us.
4353 return;
4354 } else if (UseSignalChaining) {
4355 // save the old handler in jvm
4356 save_preinstalled_handler(sig, oldAct);
4357 // libjsig also interposes the sigaction() call below and saves the
4358 // old sigaction on it own.
4359 } else {
4360 fatal("Encountered unexpected pre-existing sigaction handler "
4361 "%#lx for signal %d.", (long)oldhand, sig);
4362 }
4363 }
4364
4365 struct sigaction sigAct;
4366 sigfillset(&(sigAct.sa_mask));
4367 sigAct.sa_handler = SIG_DFL;
4368 if (!set_installed) {
4369 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4370 } else {
4371 sigAct.sa_sigaction = signalHandler;
4372 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4373 }
4374 // Save flags, which are set by ours
4375 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4376 sigflags[sig] = sigAct.sa_flags;
4377
4378 int ret = sigaction(sig, &sigAct, &oldAct);
4379 assert(ret == 0, "check");
4380
4381 void* oldhand2 = oldAct.sa_sigaction
4382 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4383 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4384 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4385 }
4386
4387 // install signal handlers for signals that HotSpot needs to
4388 // handle in order to support Java-level exception handling.
4389
4390 void os::Linux::install_signal_handlers() {
4391 if (!signal_handlers_are_installed) {
4392 signal_handlers_are_installed = true;
4393
4394 // signal-chaining
4395 typedef void (*signal_setting_t)();
4396 signal_setting_t begin_signal_setting = NULL;
4397 signal_setting_t end_signal_setting = NULL;
4398 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4399 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4400 if (begin_signal_setting != NULL) {
4401 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4402 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4403 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4404 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4405 libjsig_is_loaded = true;
4406 assert(UseSignalChaining, "should enable signal-chaining");
4407 }
4408 if (libjsig_is_loaded) {
4409 // Tell libjsig jvm is setting signal handlers
4410 (*begin_signal_setting)();
4411 }
4412
4413 set_signal_handler(SIGSEGV, true);
4414 set_signal_handler(SIGPIPE, true);
4415 set_signal_handler(SIGBUS, true);
4416 set_signal_handler(SIGILL, true);
4417 set_signal_handler(SIGFPE, true);
4418 #if defined(PPC64)
4419 set_signal_handler(SIGTRAP, true);
4420 #endif
4421 set_signal_handler(SIGXFSZ, true);
4422
4423 if (libjsig_is_loaded) {
4424 // Tell libjsig jvm finishes setting signal handlers
4425 (*end_signal_setting)();
4426 }
4427
4428 // We don't activate signal checker if libjsig is in place, we trust ourselves
4429 // and if UserSignalHandler is installed all bets are off.
4430 // Log that signal checking is off only if -verbose:jni is specified.
4431 if (CheckJNICalls) {
4432 if (libjsig_is_loaded) {
4433 if (PrintJNIResolving) {
4434 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4435 }
4436 check_signals = false;
4437 }
4438 if (AllowUserSignalHandlers) {
4439 if (PrintJNIResolving) {
4440 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4441 }
4442 check_signals = false;
4443 }
4444 }
4445 }
4446 }
4447
4448 // This is the fastest way to get thread cpu time on Linux.
4449 // Returns cpu time (user+sys) for any thread, not only for current.
4450 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4451 // It might work on 2.6.10+ with a special kernel/glibc patch.
4452 // For reference, please, see IEEE Std 1003.1-2004:
4453 // http://www.unix.org/single_unix_specification
4454
4455 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4456 struct timespec tp;
4457 int rc = os::Linux::clock_gettime(clockid, &tp);
4458 assert(rc == 0, "clock_gettime is expected to return 0 code");
4459
4460 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4461 }
4462
4463 void os::Linux::initialize_os_info() {
4464 assert(_os_version == 0, "OS info already initialized");
4465
4466 struct utsname _uname;
4467
4468 uint32_t major;
4469 uint32_t minor;
4470 uint32_t fix;
4471
4472 int rc;
4473
4474 // Kernel version is unknown if
4475 // verification below fails.
4476 _os_version = 0x01000000;
4477
4478 rc = uname(&_uname);
4479 if (rc != -1) {
4480
4481 rc = sscanf(_uname.release,"%d.%d.%d", &major, &minor, &fix);
4482 if (rc == 3) {
4483
4484 if (major < 256 && minor < 256 && fix < 256) {
4485 // Kernel version format is as expected,
4486 // set it overriding unknown state.
4487 _os_version = (major << 16) |
4488 (minor << 8 ) |
4489 (fix << 0 ) ;
4490 }
4491 }
4492 }
4493 }
4494
4495 uint32_t os::Linux::os_version() {
4496 assert(_os_version != 0, "not initialized");
4497 return _os_version & 0x00FFFFFF;
4498 }
4499
4500 bool os::Linux::os_version_is_known() {
4501 assert(_os_version != 0, "not initialized");
4502 return _os_version & 0x01000000 ? false : true;
4503 }
4504
4505 /////
4506 // glibc on Linux platform uses non-documented flag
4507 // to indicate, that some special sort of signal
4508 // trampoline is used.
4509 // We will never set this flag, and we should
4510 // ignore this flag in our diagnostic
4511 #ifdef SIGNIFICANT_SIGNAL_MASK
4512 #undef SIGNIFICANT_SIGNAL_MASK
4513 #endif
4514 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4515
4516 static const char* get_signal_handler_name(address handler,
4517 char* buf, int buflen) {
4518 int offset = 0;
4519 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4520 if (found) {
4521 // skip directory names
4522 const char *p1, *p2;
4523 p1 = buf;
4524 size_t len = strlen(os::file_separator());
4525 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4526 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4527 } else {
4528 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4529 }
4530 return buf;
4531 }
4532
4533 static void print_signal_handler(outputStream* st, int sig,
4534 char* buf, size_t buflen) {
4535 struct sigaction sa;
4536
4537 sigaction(sig, NULL, &sa);
4538
4539 // See comment for SIGNIFICANT_SIGNAL_MASK define
4540 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4541
4542 st->print("%s: ", os::exception_name(sig, buf, buflen));
4543
4544 address handler = (sa.sa_flags & SA_SIGINFO)
4545 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4546 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4547
4548 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4549 st->print("SIG_DFL");
4550 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4551 st->print("SIG_IGN");
4552 } else {
4553 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4554 }
4555
4556 st->print(", sa_mask[0]=");
4557 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4558
4559 address rh = VMError::get_resetted_sighandler(sig);
4560 // May be, handler was resetted by VMError?
4561 if (rh != NULL) {
4562 handler = rh;
4563 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4564 }
4565
4566 st->print(", sa_flags=");
4567 os::Posix::print_sa_flags(st, sa.sa_flags);
4568
4569 // Check: is it our handler?
4570 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4571 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4572 // It is our signal handler
4573 // check for flags, reset system-used one!
4574 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4575 st->print(
4576 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4577 os::Linux::get_our_sigflags(sig));
4578 }
4579 }
4580 st->cr();
4581 }
4582
4583
4584 #define DO_SIGNAL_CHECK(sig) \
4585 do { \
4586 if (!sigismember(&check_signal_done, sig)) { \
4587 os::Linux::check_signal_handler(sig); \
4588 } \
4589 } while (0)
4590
4591 // This method is a periodic task to check for misbehaving JNI applications
4592 // under CheckJNI, we can add any periodic checks here
4593
4594 void os::run_periodic_checks() {
4595 if (check_signals == false) return;
4596
4597 // SEGV and BUS if overridden could potentially prevent
4598 // generation of hs*.log in the event of a crash, debugging
4599 // such a case can be very challenging, so we absolutely
4600 // check the following for a good measure:
4601 DO_SIGNAL_CHECK(SIGSEGV);
4602 DO_SIGNAL_CHECK(SIGILL);
4603 DO_SIGNAL_CHECK(SIGFPE);
4604 DO_SIGNAL_CHECK(SIGBUS);
4605 DO_SIGNAL_CHECK(SIGPIPE);
4606 DO_SIGNAL_CHECK(SIGXFSZ);
4607 #if defined(PPC64)
4608 DO_SIGNAL_CHECK(SIGTRAP);
4609 #endif
4610
4611 // ReduceSignalUsage allows the user to override these handlers
4612 // see comments at the very top and jvm_solaris.h
4613 if (!ReduceSignalUsage) {
4614 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4615 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4616 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4617 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4618 }
4619
4620 DO_SIGNAL_CHECK(SR_signum);
4621 }
4622
4623 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4624
4625 static os_sigaction_t os_sigaction = NULL;
4626
4627 void os::Linux::check_signal_handler(int sig) {
4628 char buf[O_BUFLEN];
4629 address jvmHandler = NULL;
4630
4631
4632 struct sigaction act;
4633 if (os_sigaction == NULL) {
4634 // only trust the default sigaction, in case it has been interposed
4635 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4636 if (os_sigaction == NULL) return;
4637 }
4638
4639 os_sigaction(sig, (struct sigaction*)NULL, &act);
4640
4641
4642 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4643
4644 address thisHandler = (act.sa_flags & SA_SIGINFO)
4645 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4646 : CAST_FROM_FN_PTR(address, act.sa_handler);
4647
4648
4649 switch (sig) {
4650 case SIGSEGV:
4651 case SIGBUS:
4652 case SIGFPE:
4653 case SIGPIPE:
4654 case SIGILL:
4655 case SIGXFSZ:
4656 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4657 break;
4658
4659 case SHUTDOWN1_SIGNAL:
4660 case SHUTDOWN2_SIGNAL:
4661 case SHUTDOWN3_SIGNAL:
4662 case BREAK_SIGNAL:
4663 jvmHandler = (address)user_handler();
4664 break;
4665
4666 default:
4667 if (sig == SR_signum) {
4668 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4669 } else {
4670 return;
4671 }
4672 break;
4673 }
4674
4675 if (thisHandler != jvmHandler) {
4676 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4677 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4678 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4679 // No need to check this sig any longer
4680 sigaddset(&check_signal_done, sig);
4681 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4682 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4683 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4684 exception_name(sig, buf, O_BUFLEN));
4685 }
4686 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4687 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4688 tty->print("expected:");
4689 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4690 tty->cr();
4691 tty->print(" found:");
4692 os::Posix::print_sa_flags(tty, act.sa_flags);
4693 tty->cr();
4694 // No need to check this sig any longer
4695 sigaddset(&check_signal_done, sig);
4696 }
4697
4698 // Dump all the signal
4699 if (sigismember(&check_signal_done, sig)) {
4700 print_signal_handlers(tty, buf, O_BUFLEN);
4701 }
4702 }
4703
4704 extern void report_error(char* file_name, int line_no, char* title,
4705 char* format, ...);
4706
4707 // this is called _before_ the most of global arguments have been parsed
4708 void os::init(void) {
4709 char dummy; // used to get a guess on initial stack address
4710 // first_hrtime = gethrtime();
4711
4712 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4713
4714 init_random(1234567);
4715
4716 ThreadCritical::initialize();
4717
4718 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4719 if (Linux::page_size() == -1) {
4720 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4721 os::strerror(errno));
4722 }
4723 init_page_sizes((size_t) Linux::page_size());
4724
4725 Linux::initialize_system_info();
4726
4727 Linux::initialize_os_info();
4728
4729 // main_thread points to the aboriginal thread
4730 Linux::_main_thread = pthread_self();
4731
4732 Linux::clock_init();
4733 initial_time_count = javaTimeNanos();
4734
4735 // pthread_condattr initialization for monotonic clock
4736 int status;
4737 pthread_condattr_t* _condattr = os::Linux::condAttr();
4738 if ((status = pthread_condattr_init(_condattr)) != 0) {
4739 fatal("pthread_condattr_init: %s", os::strerror(status));
4740 }
4741 // Only set the clock if CLOCK_MONOTONIC is available
4742 if (os::supports_monotonic_clock()) {
4743 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4744 if (status == EINVAL) {
4745 warning("Unable to use monotonic clock with relative timed-waits" \
4746 " - changes to the time-of-day clock may have adverse affects");
4747 } else {
4748 fatal("pthread_condattr_setclock: %s", os::strerror(status));
4749 }
4750 }
4751 }
4752 // else it defaults to CLOCK_REALTIME
4753
4754 // retrieve entry point for pthread_setname_np
4755 Linux::_pthread_setname_np =
4756 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4757
4758 }
4759
4760 // To install functions for atexit system call
4761 extern "C" {
4762 static void perfMemory_exit_helper() {
4763 perfMemory_exit();
4764 }
4765 }
4766
4767 // this is called _after_ the global arguments have been parsed
4768 jint os::init_2(void) {
4769 Linux::fast_thread_clock_init();
4770
4771 // Allocate a single page and mark it as readable for safepoint polling
4772 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4773 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4774
4775 os::set_polling_page(polling_page);
4776 log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(polling_page));
4777
4778 if (!UseMembar) {
4779 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4780 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4781 os::set_memory_serialize_page(mem_serialize_page);
4782 log_info(os)("Memory Serialize Page address: " INTPTR_FORMAT, p2i(mem_serialize_page));
4783 }
4784
4785 // initialize suspend/resume support - must do this before signal_sets_init()
4786 if (SR_initialize() != 0) {
4787 perror("SR_initialize failed");
4788 return JNI_ERR;
4789 }
4790
4791 Linux::signal_sets_init();
4792 Linux::install_signal_handlers();
4793
4794 // Check minimum allowable stack size for thread creation and to initialize
4795 // the java system classes, including StackOverflowError - depends on page
4796 // size. Add two 4K pages for compiler2 recursion in main thread.
4797 // Add in 4*BytesPerWord 4K pages to account for VM stack during
4798 // class initialization depending on 32 or 64 bit VM.
4799 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4800 JavaThread::stack_guard_zone_size() +
4801 JavaThread::stack_shadow_zone_size() +
4802 (4*BytesPerWord COMPILER2_PRESENT(+2)) * 4 * K);
4803
4804 os::Linux::min_stack_allowed = align_size_up(os::Linux::min_stack_allowed, os::vm_page_size());
4805
4806 size_t threadStackSizeInBytes = ThreadStackSize * K;
4807 if (threadStackSizeInBytes != 0 &&
4808 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4809 tty->print_cr("\nThe stack size specified is too small, "
4810 "Specify at least " SIZE_FORMAT "k",
4811 os::Linux::min_stack_allowed/ K);
4812 return JNI_ERR;
4813 }
4814
4815 // Make the stack size a multiple of the page size so that
4816 // the yellow/red zones can be guarded.
4817 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4818 vm_page_size()));
4819
4820 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4821
4822 #if defined(IA32)
4823 workaround_expand_exec_shield_cs_limit();
4824 #endif
4825
4826 Linux::libpthread_init();
4827 log_info(os)("HotSpot is running with %s, %s",
4828 Linux::glibc_version(), Linux::libpthread_version());
4829
4830 if (UseNUMA) {
4831 if (!Linux::libnuma_init()) {
4832 UseNUMA = false;
4833 } else {
4834 if ((Linux::numa_max_node() < 1)) {
4835 // There's only one node(they start from 0), disable NUMA.
4836 UseNUMA = false;
4837 }
4838 }
4839 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4840 // we can make the adaptive lgrp chunk resizing work. If the user specified
4841 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4842 // disable adaptive resizing.
4843 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4844 if (FLAG_IS_DEFAULT(UseNUMA)) {
4845 UseNUMA = false;
4846 } else {
4847 if (FLAG_IS_DEFAULT(UseLargePages) &&
4848 FLAG_IS_DEFAULT(UseSHM) &&
4849 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4850 UseLargePages = false;
4851 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4852 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4853 UseAdaptiveSizePolicy = false;
4854 UseAdaptiveNUMAChunkSizing = false;
4855 }
4856 }
4857 }
4858 if (!UseNUMA && ForceNUMA) {
4859 UseNUMA = true;
4860 }
4861 }
4862
4863 if (MaxFDLimit) {
4864 // set the number of file descriptors to max. print out error
4865 // if getrlimit/setrlimit fails but continue regardless.
4866 struct rlimit nbr_files;
4867 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4868 if (status != 0) {
4869 log_info(os)("os::init_2 getrlimit failed: %s", os::strerror(errno));
4870 } else {
4871 nbr_files.rlim_cur = nbr_files.rlim_max;
4872 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4873 if (status != 0) {
4874 log_info(os)("os::init_2 setrlimit failed: %s", os::strerror(errno));
4875 }
4876 }
4877 }
4878
4879 // Initialize lock used to serialize thread creation (see os::create_thread)
4880 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4881
4882 // at-exit methods are called in the reverse order of their registration.
4883 // atexit functions are called on return from main or as a result of a
4884 // call to exit(3C). There can be only 32 of these functions registered
4885 // and atexit() does not set errno.
4886
4887 if (PerfAllowAtExitRegistration) {
4888 // only register atexit functions if PerfAllowAtExitRegistration is set.
4889 // atexit functions can be delayed until process exit time, which
4890 // can be problematic for embedded VM situations. Embedded VMs should
4891 // call DestroyJavaVM() to assure that VM resources are released.
4892
4893 // note: perfMemory_exit_helper atexit function may be removed in
4894 // the future if the appropriate cleanup code can be added to the
4895 // VM_Exit VMOperation's doit method.
4896 if (atexit(perfMemory_exit_helper) != 0) {
4897 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4898 }
4899 }
4900
4901 // initialize thread priority policy
4902 prio_init();
4903
4904 return JNI_OK;
4905 }
4906
4907 // Mark the polling page as unreadable
4908 void os::make_polling_page_unreadable(void) {
4909 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4910 fatal("Could not disable polling page");
4911 }
4912 }
4913
4914 // Mark the polling page as readable
4915 void os::make_polling_page_readable(void) {
4916 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4917 fatal("Could not enable polling page");
4918 }
4919 }
4920
4921 // older glibc versions don't have this macro (which expands to
4922 // an optimized bit-counting function) so we have to roll our own
4923 #ifndef CPU_COUNT
4924
4925 static int _cpu_count(const cpu_set_t* cpus) {
4926 int count = 0;
4927 // only look up to the number of configured processors
4928 for (int i = 0; i < os::processor_count(); i++) {
4929 if (CPU_ISSET(i, cpus)) {
4930 count++;
4931 }
4932 }
4933 return count;
4934 }
4935
4936 #define CPU_COUNT(cpus) _cpu_count(cpus)
4937
4938 #endif // CPU_COUNT
4939
4940 // Get the current number of available processors for this process.
4941 // This value can change at any time during a process's lifetime.
4942 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4943 // If it appears there may be more than 1024 processors then we do a
4944 // dynamic check - see 6515172 for details.
4945 // If anything goes wrong we fallback to returning the number of online
4946 // processors - which can be greater than the number available to the process.
4947 int os::active_processor_count() {
4948 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4949 cpu_set_t* cpus_p = &cpus;
4950 int cpus_size = sizeof(cpu_set_t);
4951
4952 int configured_cpus = processor_count(); // upper bound on available cpus
4953 int cpu_count = 0;
4954
4955 // old build platforms may not support dynamic cpu sets
4956 #ifdef CPU_ALLOC
4957
4958 // To enable easy testing of the dynamic path on different platforms we
4959 // introduce a diagnostic flag: UseCpuAllocPath
4960 if (configured_cpus >= CPU_SETSIZE || UseCpuAllocPath) {
4961 // kernel may use a mask bigger than cpu_set_t
4962 log_trace(os)("active_processor_count: using dynamic path %s"
4963 "- configured processors: %d",
4964 UseCpuAllocPath ? "(forced) " : "",
4965 configured_cpus);
4966 cpus_p = CPU_ALLOC(configured_cpus);
4967 if (cpus_p != NULL) {
4968 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4969 // zero it just to be safe
4970 CPU_ZERO_S(cpus_size, cpus_p);
4971 }
4972 else {
4973 // failed to allocate so fallback to online cpus
4974 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4975 log_trace(os)("active_processor_count: "
4976 "CPU_ALLOC failed (%s) - using "
4977 "online processor count: %d",
4978 os::strerror(errno), online_cpus);
4979 return online_cpus;
4980 }
4981 }
4982 else {
4983 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4984 configured_cpus);
4985 }
4986 #else // CPU_ALLOC
4987 // these stubs won't be executed
4988 #define CPU_COUNT_S(size, cpus) -1
4989 #define CPU_FREE(cpus)
4990
4991 log_trace(os)("active_processor_count: only static path available - configured processors: %d",
4992 configured_cpus);
4993 #endif // CPU_ALLOC
4994
4995 // pid 0 means the current thread - which we have to assume represents the process
4996 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4997 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
4998 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4999 }
5000 else {
5001 cpu_count = CPU_COUNT(cpus_p);
5002 }
5003 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5004 }
5005 else {
5006 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5007 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5008 "which may exceed available processors", os::strerror(errno), cpu_count);
5009 }
5010
5011 if (cpus_p != &cpus) { // can only be true when CPU_ALLOC used
5012 CPU_FREE(cpus_p);
5013 }
5014
5015 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
5016 return cpu_count;
5017 }
5018
5019 void os::set_native_thread_name(const char *name) {
5020 if (Linux::_pthread_setname_np) {
5021 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5022 snprintf(buf, sizeof(buf), "%s", name);
5023 buf[sizeof(buf) - 1] = '\0';
5024 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5025 // ERANGE should not happen; all other errors should just be ignored.
5026 assert(rc != ERANGE, "pthread_setname_np failed");
5027 }
5028 }
5029
5030 bool os::distribute_processes(uint length, uint* distribution) {
5031 // Not yet implemented.
5032 return false;
5033 }
5034
5035 bool os::bind_to_processor(uint processor_id) {
5036 // Not yet implemented.
5037 return false;
5038 }
5039
5040 ///
5041
5042 void os::SuspendedThreadTask::internal_do_task() {
5043 if (do_suspend(_thread->osthread())) {
5044 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5045 do_task(context);
5046 do_resume(_thread->osthread());
5047 }
5048 }
5049
5050 class PcFetcher : public os::SuspendedThreadTask {
5051 public:
5052 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5053 ExtendedPC result();
5054 protected:
5055 void do_task(const os::SuspendedThreadTaskContext& context);
5056 private:
5057 ExtendedPC _epc;
5058 };
5059
5060 ExtendedPC PcFetcher::result() {
5061 guarantee(is_done(), "task is not done yet.");
5062 return _epc;
5063 }
5064
5065 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5066 Thread* thread = context.thread();
5067 OSThread* osthread = thread->osthread();
5068 if (osthread->ucontext() != NULL) {
5069 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
5070 } else {
5071 // NULL context is unexpected, double-check this is the VMThread
5072 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5073 }
5074 }
5075
5076 // Suspends the target using the signal mechanism and then grabs the PC before
5077 // resuming the target. Used by the flat-profiler only
5078 ExtendedPC os::get_thread_pc(Thread* thread) {
5079 // Make sure that it is called by the watcher for the VMThread
5080 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5081 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5082
5083 PcFetcher fetcher(thread);
5084 fetcher.run();
5085 return fetcher.result();
5086 }
5087
5088 ////////////////////////////////////////////////////////////////////////////////
5089 // debug support
5090
5091 bool os::find(address addr, outputStream* st) {
5092 Dl_info dlinfo;
5093 memset(&dlinfo, 0, sizeof(dlinfo));
5094 if (dladdr(addr, &dlinfo) != 0) {
5095 st->print(PTR_FORMAT ": ", p2i(addr));
5096 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5097 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
5098 p2i(addr) - p2i(dlinfo.dli_saddr));
5099 } else if (dlinfo.dli_fbase != NULL) {
5100 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
5101 } else {
5102 st->print("<absolute address>");
5103 }
5104 if (dlinfo.dli_fname != NULL) {
5105 st->print(" in %s", dlinfo.dli_fname);
5106 }
5107 if (dlinfo.dli_fbase != NULL) {
5108 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
5109 }
5110 st->cr();
5111
5112 if (Verbose) {
5113 // decode some bytes around the PC
5114 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5115 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5116 address lowest = (address) dlinfo.dli_sname;
5117 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5118 if (begin < lowest) begin = lowest;
5119 Dl_info dlinfo2;
5120 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5121 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
5122 end = (address) dlinfo2.dli_saddr;
5123 }
5124 Disassembler::decode(begin, end, st);
5125 }
5126 return true;
5127 }
5128 return false;
5129 }
5130
5131 ////////////////////////////////////////////////////////////////////////////////
5132 // misc
5133
5134 // This does not do anything on Linux. This is basically a hook for being
5135 // able to use structured exception handling (thread-local exception filters)
5136 // on, e.g., Win32.
5137 void
5138 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
5139 JavaCallArguments* args, Thread* thread) {
5140 f(value, method, args, thread);
5141 }
5142
5143 void os::print_statistics() {
5144 }
5145
5146 bool os::message_box(const char* title, const char* message) {
5147 int i;
5148 fdStream err(defaultStream::error_fd());
5149 for (i = 0; i < 78; i++) err.print_raw("=");
5150 err.cr();
5151 err.print_raw_cr(title);
5152 for (i = 0; i < 78; i++) err.print_raw("-");
5153 err.cr();
5154 err.print_raw_cr(message);
5155 for (i = 0; i < 78; i++) err.print_raw("=");
5156 err.cr();
5157
5158 char buf[16];
5159 // Prevent process from exiting upon "read error" without consuming all CPU
5160 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5161
5162 return buf[0] == 'y' || buf[0] == 'Y';
5163 }
5164
5165 int os::stat(const char *path, struct stat *sbuf) {
5166 char pathbuf[MAX_PATH];
5167 if (strlen(path) > MAX_PATH - 1) {
5168 errno = ENAMETOOLONG;
5169 return -1;
5170 }
5171 os::native_path(strcpy(pathbuf, path));
5172 return ::stat(pathbuf, sbuf);
5173 }
5174
5175 bool os::check_heap(bool force) {
5176 return true;
5177 }
5178
5179 // Is a (classpath) directory empty?
5180 bool os::dir_is_empty(const char* path) {
5181 DIR *dir = NULL;
5182 struct dirent *ptr;
5183
5184 dir = opendir(path);
5185 if (dir == NULL) return true;
5186
5187 // Scan the directory
5188 bool result = true;
5189 char buf[sizeof(struct dirent) + MAX_PATH];
5190 while (result && (ptr = ::readdir(dir)) != NULL) {
5191 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5192 result = false;
5193 }
5194 }
5195 closedir(dir);
5196 return result;
5197 }
5198
5199 // This code originates from JDK's sysOpen and open64_w
5200 // from src/solaris/hpi/src/system_md.c
5201
5202 int os::open(const char *path, int oflag, int mode) {
5203 if (strlen(path) > MAX_PATH - 1) {
5204 errno = ENAMETOOLONG;
5205 return -1;
5206 }
5207
5208 // All file descriptors that are opened in the Java process and not
5209 // specifically destined for a subprocess should have the close-on-exec
5210 // flag set. If we don't set it, then careless 3rd party native code
5211 // might fork and exec without closing all appropriate file descriptors
5212 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5213 // turn might:
5214 //
5215 // - cause end-of-file to fail to be detected on some file
5216 // descriptors, resulting in mysterious hangs, or
5217 //
5218 // - might cause an fopen in the subprocess to fail on a system
5219 // suffering from bug 1085341.
5220 //
5221 // (Yes, the default setting of the close-on-exec flag is a Unix
5222 // design flaw)
5223 //
5224 // See:
5225 // 1085341: 32-bit stdio routines should support file descriptors >255
5226 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5227 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5228 //
5229 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5230 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5231 // because it saves a system call and removes a small window where the flag
5232 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5233 // and we fall back to using FD_CLOEXEC (see below).
5234 #ifdef O_CLOEXEC
5235 oflag |= O_CLOEXEC;
5236 #endif
5237
5238 int fd = ::open64(path, oflag, mode);
5239 if (fd == -1) return -1;
5240
5241 //If the open succeeded, the file might still be a directory
5242 {
5243 struct stat64 buf64;
5244 int ret = ::fstat64(fd, &buf64);
5245 int st_mode = buf64.st_mode;
5246
5247 if (ret != -1) {
5248 if ((st_mode & S_IFMT) == S_IFDIR) {
5249 errno = EISDIR;
5250 ::close(fd);
5251 return -1;
5252 }
5253 } else {
5254 ::close(fd);
5255 return -1;
5256 }
5257 }
5258
5259 #ifdef FD_CLOEXEC
5260 // Validate that the use of the O_CLOEXEC flag on open above worked.
5261 // With recent kernels, we will perform this check exactly once.
5262 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5263 if (!O_CLOEXEC_is_known_to_work) {
5264 int flags = ::fcntl(fd, F_GETFD);
5265 if (flags != -1) {
5266 if ((flags & FD_CLOEXEC) != 0)
5267 O_CLOEXEC_is_known_to_work = 1;
5268 else
5269 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5270 }
5271 }
5272 #endif
5273
5274 return fd;
5275 }
5276
5277
5278 // create binary file, rewriting existing file if required
5279 int os::create_binary_file(const char* path, bool rewrite_existing) {
5280 int oflags = O_WRONLY | O_CREAT;
5281 if (!rewrite_existing) {
5282 oflags |= O_EXCL;
5283 }
5284 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5285 }
5286
5287 // return current position of file pointer
5288 jlong os::current_file_offset(int fd) {
5289 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5290 }
5291
5292 // move file pointer to the specified offset
5293 jlong os::seek_to_file_offset(int fd, jlong offset) {
5294 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5295 }
5296
5297 // This code originates from JDK's sysAvailable
5298 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5299
5300 int os::available(int fd, jlong *bytes) {
5301 jlong cur, end;
5302 int mode;
5303 struct stat64 buf64;
5304
5305 if (::fstat64(fd, &buf64) >= 0) {
5306 mode = buf64.st_mode;
5307 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5308 int n;
5309 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5310 *bytes = n;
5311 return 1;
5312 }
5313 }
5314 }
5315 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5316 return 0;
5317 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5318 return 0;
5319 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5320 return 0;
5321 }
5322 *bytes = end - cur;
5323 return 1;
5324 }
5325
5326 // Map a block of memory.
5327 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5328 char *addr, size_t bytes, bool read_only,
5329 bool allow_exec) {
5330 int prot;
5331 int flags = MAP_PRIVATE;
5332
5333 if (read_only) {
5334 prot = PROT_READ;
5335 } else {
5336 prot = PROT_READ | PROT_WRITE;
5337 }
5338
5339 if (allow_exec) {
5340 prot |= PROT_EXEC;
5341 }
5342
5343 if (addr != NULL) {
5344 flags |= MAP_FIXED;
5345 }
5346
5347 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5348 fd, file_offset);
5349 if (mapped_address == MAP_FAILED) {
5350 return NULL;
5351 }
5352 return mapped_address;
5353 }
5354
5355
5356 // Remap a block of memory.
5357 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5358 char *addr, size_t bytes, bool read_only,
5359 bool allow_exec) {
5360 // same as map_memory() on this OS
5361 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5362 allow_exec);
5363 }
5364
5365
5366 // Unmap a block of memory.
5367 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5368 return munmap(addr, bytes) == 0;
5369 }
5370
5371 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5372
5373 static clockid_t thread_cpu_clockid(Thread* thread) {
5374 pthread_t tid = thread->osthread()->pthread_id();
5375 clockid_t clockid;
5376
5377 // Get thread clockid
5378 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5379 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5380 return clockid;
5381 }
5382
5383 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5384 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5385 // of a thread.
5386 //
5387 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5388 // the fast estimate available on the platform.
5389
5390 jlong os::current_thread_cpu_time() {
5391 if (os::Linux::supports_fast_thread_cpu_time()) {
5392 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5393 } else {
5394 // return user + sys since the cost is the same
5395 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5396 }
5397 }
5398
5399 jlong os::thread_cpu_time(Thread* thread) {
5400 // consistent with what current_thread_cpu_time() returns
5401 if (os::Linux::supports_fast_thread_cpu_time()) {
5402 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5403 } else {
5404 return slow_thread_cpu_time(thread, true /* user + sys */);
5405 }
5406 }
5407
5408 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5409 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5410 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5411 } else {
5412 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5413 }
5414 }
5415
5416 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5417 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5418 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5419 } else {
5420 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5421 }
5422 }
5423
5424 // -1 on error.
5425 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5426 pid_t tid = thread->osthread()->thread_id();
5427 char *s;
5428 char stat[2048];
5429 int statlen;
5430 char proc_name[64];
5431 int count;
5432 long sys_time, user_time;
5433 char cdummy;
5434 int idummy;
5435 long ldummy;
5436 FILE *fp;
5437
5438 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5439 fp = fopen(proc_name, "r");
5440 if (fp == NULL) return -1;
5441 statlen = fread(stat, 1, 2047, fp);
5442 stat[statlen] = '\0';
5443 fclose(fp);
5444
5445 // Skip pid and the command string. Note that we could be dealing with
5446 // weird command names, e.g. user could decide to rename java launcher
5447 // to "java 1.4.2 :)", then the stat file would look like
5448 // 1234 (java 1.4.2 :)) R ... ...
5449 // We don't really need to know the command string, just find the last
5450 // occurrence of ")" and then start parsing from there. See bug 4726580.
5451 s = strrchr(stat, ')');
5452 if (s == NULL) return -1;
5453
5454 // Skip blank chars
5455 do { s++; } while (s && isspace(*s));
5456
5457 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5458 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5459 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5460 &user_time, &sys_time);
5461 if (count != 13) return -1;
5462 if (user_sys_cpu_time) {
5463 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5464 } else {
5465 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5466 }
5467 }
5468
5469 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5470 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5471 info_ptr->may_skip_backward = false; // elapsed time not wall time
5472 info_ptr->may_skip_forward = false; // elapsed time not wall time
5473 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5474 }
5475
5476 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5477 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5478 info_ptr->may_skip_backward = false; // elapsed time not wall time
5479 info_ptr->may_skip_forward = false; // elapsed time not wall time
5480 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5481 }
5482
5483 bool os::is_thread_cpu_time_supported() {
5484 return true;
5485 }
5486
5487 // System loadavg support. Returns -1 if load average cannot be obtained.
5488 // Linux doesn't yet have a (official) notion of processor sets,
5489 // so just return the system wide load average.
5490 int os::loadavg(double loadavg[], int nelem) {
5491 return ::getloadavg(loadavg, nelem);
5492 }
5493
5494 void os::pause() {
5495 char filename[MAX_PATH];
5496 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5497 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5498 } else {
5499 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5500 }
5501
5502 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5503 if (fd != -1) {
5504 struct stat buf;
5505 ::close(fd);
5506 while (::stat(filename, &buf) == 0) {
5507 (void)::poll(NULL, 0, 100);
5508 }
5509 } else {
5510 jio_fprintf(stderr,
5511 "Could not open pause file '%s', continuing immediately.\n", filename);
5512 }
5513 }
5514
5515
5516 // Refer to the comments in os_solaris.cpp park-unpark. The next two
5517 // comment paragraphs are worth repeating here:
5518 //
5519 // Assumption:
5520 // Only one parker can exist on an event, which is why we allocate
5521 // them per-thread. Multiple unparkers can coexist.
5522 //
5523 // _Event serves as a restricted-range semaphore.
5524 // -1 : thread is blocked, i.e. there is a waiter
5525 // 0 : neutral: thread is running or ready,
5526 // could have been signaled after a wait started
5527 // 1 : signaled - thread is running or ready
5528 //
5529
5530 // utility to compute the abstime argument to timedwait:
5531 // millis is the relative timeout time
5532 // abstime will be the absolute timeout time
5533 // TODO: replace compute_abstime() with unpackTime()
5534
5535 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5536 if (millis < 0) millis = 0;
5537
5538 jlong seconds = millis / 1000;
5539 millis %= 1000;
5540 if (seconds > 50000000) { // see man cond_timedwait(3T)
5541 seconds = 50000000;
5542 }
5543
5544 if (os::supports_monotonic_clock()) {
5545 struct timespec now;
5546 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5547 assert_status(status == 0, status, "clock_gettime");
5548 abstime->tv_sec = now.tv_sec + seconds;
5549 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5550 if (nanos >= NANOSECS_PER_SEC) {
5551 abstime->tv_sec += 1;
5552 nanos -= NANOSECS_PER_SEC;
5553 }
5554 abstime->tv_nsec = nanos;
5555 } else {
5556 struct timeval now;
5557 int status = gettimeofday(&now, NULL);
5558 assert(status == 0, "gettimeofday");
5559 abstime->tv_sec = now.tv_sec + seconds;
5560 long usec = now.tv_usec + millis * 1000;
5561 if (usec >= 1000000) {
5562 abstime->tv_sec += 1;
5563 usec -= 1000000;
5564 }
5565 abstime->tv_nsec = usec * 1000;
5566 }
5567 return abstime;
5568 }
5569
5570 void os::PlatformEvent::park() { // AKA "down()"
5571 // Transitions for _Event:
5572 // -1 => -1 : illegal
5573 // 1 => 0 : pass - return immediately
5574 // 0 => -1 : block; then set _Event to 0 before returning
5575
5576 // Invariant: Only the thread associated with the Event/PlatformEvent
5577 // may call park().
5578 // TODO: assert that _Assoc != NULL or _Assoc == Self
5579 assert(_nParked == 0, "invariant");
5580
5581 int v;
5582 for (;;) {
5583 v = _Event;
5584 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5585 }
5586 guarantee(v >= 0, "invariant");
5587 if (v == 0) {
5588 // Do this the hard way by blocking ...
5589 int status = pthread_mutex_lock(_mutex);
5590 assert_status(status == 0, status, "mutex_lock");
5591 guarantee(_nParked == 0, "invariant");
5592 ++_nParked;
5593 while (_Event < 0) {
5594 status = pthread_cond_wait(_cond, _mutex);
5595 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5596 // Treat this the same as if the wait was interrupted
5597 if (status == ETIME) { status = EINTR; }
5598 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5599 }
5600 --_nParked;
5601
5602 _Event = 0;
5603 status = pthread_mutex_unlock(_mutex);
5604 assert_status(status == 0, status, "mutex_unlock");
5605 // Paranoia to ensure our locked and lock-free paths interact
5606 // correctly with each other.
5607 OrderAccess::fence();
5608 }
5609 guarantee(_Event >= 0, "invariant");
5610 }
5611
5612 int os::PlatformEvent::park(jlong millis) {
5613 // Transitions for _Event:
5614 // -1 => -1 : illegal
5615 // 1 => 0 : pass - return immediately
5616 // 0 => -1 : block; then set _Event to 0 before returning
5617
5618 guarantee(_nParked == 0, "invariant");
5619
5620 int v;
5621 for (;;) {
5622 v = _Event;
5623 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5624 }
5625 guarantee(v >= 0, "invariant");
5626 if (v != 0) return OS_OK;
5627
5628 // We do this the hard way, by blocking the thread.
5629 // Consider enforcing a minimum timeout value.
5630 struct timespec abst;
5631 compute_abstime(&abst, millis);
5632
5633 int ret = OS_TIMEOUT;
5634 int status = pthread_mutex_lock(_mutex);
5635 assert_status(status == 0, status, "mutex_lock");
5636 guarantee(_nParked == 0, "invariant");
5637 ++_nParked;
5638
5639 // Object.wait(timo) will return because of
5640 // (a) notification
5641 // (b) timeout
5642 // (c) thread.interrupt
5643 //
5644 // Thread.interrupt and object.notify{All} both call Event::set.
5645 // That is, we treat thread.interrupt as a special case of notification.
5646 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
5647 // We assume all ETIME returns are valid.
5648 //
5649 // TODO: properly differentiate simultaneous notify+interrupt.
5650 // In that case, we should propagate the notify to another waiter.
5651
5652 while (_Event < 0) {
5653 status = pthread_cond_timedwait(_cond, _mutex, &abst);
5654 assert_status(status == 0 || status == EINTR ||
5655 status == ETIME || status == ETIMEDOUT,
5656 status, "cond_timedwait");
5657 if (!FilterSpuriousWakeups) break; // previous semantics
5658 if (status == ETIME || status == ETIMEDOUT) break;
5659 // We consume and ignore EINTR and spurious wakeups.
5660 }
5661 --_nParked;
5662 if (_Event >= 0) {
5663 ret = OS_OK;
5664 }
5665 _Event = 0;
5666 status = pthread_mutex_unlock(_mutex);
5667 assert_status(status == 0, status, "mutex_unlock");
5668 assert(_nParked == 0, "invariant");
5669 // Paranoia to ensure our locked and lock-free paths interact
5670 // correctly with each other.
5671 OrderAccess::fence();
5672 return ret;
5673 }
5674
5675 void os::PlatformEvent::unpark() {
5676 // Transitions for _Event:
5677 // 0 => 1 : just return
5678 // 1 => 1 : just return
5679 // -1 => either 0 or 1; must signal target thread
5680 // That is, we can safely transition _Event from -1 to either
5681 // 0 or 1.
5682 // See also: "Semaphores in Plan 9" by Mullender & Cox
5683 //
5684 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5685 // that it will take two back-to-back park() calls for the owning
5686 // thread to block. This has the benefit of forcing a spurious return
5687 // from the first park() call after an unpark() call which will help
5688 // shake out uses of park() and unpark() without condition variables.
5689
5690 if (Atomic::xchg(1, &_Event) >= 0) return;
5691
5692 // Wait for the thread associated with the event to vacate
5693 int status = pthread_mutex_lock(_mutex);
5694 assert_status(status == 0, status, "mutex_lock");
5695 int AnyWaiters = _nParked;
5696 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5697 status = pthread_mutex_unlock(_mutex);
5698 assert_status(status == 0, status, "mutex_unlock");
5699 if (AnyWaiters != 0) {
5700 // Note that we signal() *after* dropping the lock for "immortal" Events.
5701 // This is safe and avoids a common class of futile wakeups. In rare
5702 // circumstances this can cause a thread to return prematurely from
5703 // cond_{timed}wait() but the spurious wakeup is benign and the victim
5704 // will simply re-test the condition and re-park itself.
5705 // This provides particular benefit if the underlying platform does not
5706 // provide wait morphing.
5707 status = pthread_cond_signal(_cond);
5708 assert_status(status == 0, status, "cond_signal");
5709 }
5710 }
5711
5712
5713 // JSR166
5714 // -------------------------------------------------------
5715
5716 // The solaris and linux implementations of park/unpark are fairly
5717 // conservative for now, but can be improved. They currently use a
5718 // mutex/condvar pair, plus a a count.
5719 // Park decrements count if > 0, else does a condvar wait. Unpark
5720 // sets count to 1 and signals condvar. Only one thread ever waits
5721 // on the condvar. Contention seen when trying to park implies that someone
5722 // is unparking you, so don't wait. And spurious returns are fine, so there
5723 // is no need to track notifications.
5724
5725 // This code is common to linux and solaris and will be moved to a
5726 // common place in dolphin.
5727 //
5728 // The passed in time value is either a relative time in nanoseconds
5729 // or an absolute time in milliseconds. Either way it has to be unpacked
5730 // into suitable seconds and nanoseconds components and stored in the
5731 // given timespec structure.
5732 // Given time is a 64-bit value and the time_t used in the timespec is only
5733 // a signed-32-bit value (except on 64-bit Linux) we have to watch for
5734 // overflow if times way in the future are given. Further on Solaris versions
5735 // prior to 10 there is a restriction (see cond_timedwait) that the specified
5736 // number of seconds, in abstime, is less than current_time + 100,000,000.
5737 // As it will be 28 years before "now + 100000000" will overflow we can
5738 // ignore overflow and just impose a hard-limit on seconds using the value
5739 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
5740 // years from "now".
5741
5742 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5743 assert(time > 0, "convertTime");
5744 time_t max_secs = 0;
5745
5746 if (!os::supports_monotonic_clock() || isAbsolute) {
5747 struct timeval now;
5748 int status = gettimeofday(&now, NULL);
5749 assert(status == 0, "gettimeofday");
5750
5751 max_secs = now.tv_sec + MAX_SECS;
5752
5753 if (isAbsolute) {
5754 jlong secs = time / 1000;
5755 if (secs > max_secs) {
5756 absTime->tv_sec = max_secs;
5757 } else {
5758 absTime->tv_sec = secs;
5759 }
5760 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5761 } else {
5762 jlong secs = time / NANOSECS_PER_SEC;
5763 if (secs >= MAX_SECS) {
5764 absTime->tv_sec = max_secs;
5765 absTime->tv_nsec = 0;
5766 } else {
5767 absTime->tv_sec = now.tv_sec + secs;
5768 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5769 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5770 absTime->tv_nsec -= NANOSECS_PER_SEC;
5771 ++absTime->tv_sec; // note: this must be <= max_secs
5772 }
5773 }
5774 }
5775 } else {
5776 // must be relative using monotonic clock
5777 struct timespec now;
5778 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5779 assert_status(status == 0, status, "clock_gettime");
5780 max_secs = now.tv_sec + MAX_SECS;
5781 jlong secs = time / NANOSECS_PER_SEC;
5782 if (secs >= MAX_SECS) {
5783 absTime->tv_sec = max_secs;
5784 absTime->tv_nsec = 0;
5785 } else {
5786 absTime->tv_sec = now.tv_sec + secs;
5787 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5788 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5789 absTime->tv_nsec -= NANOSECS_PER_SEC;
5790 ++absTime->tv_sec; // note: this must be <= max_secs
5791 }
5792 }
5793 }
5794 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5795 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5796 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5797 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5798 }
5799
5800 void Parker::park(bool isAbsolute, jlong time) {
5801 // Ideally we'd do something useful while spinning, such
5802 // as calling unpackTime().
5803
5804 // Optional fast-path check:
5805 // Return immediately if a permit is available.
5806 // We depend on Atomic::xchg() having full barrier semantics
5807 // since we are doing a lock-free update to _counter.
5808 if (Atomic::xchg(0, &_counter) > 0) return;
5809
5810 Thread* thread = Thread::current();
5811 assert(thread->is_Java_thread(), "Must be JavaThread");
5812 JavaThread *jt = (JavaThread *)thread;
5813
5814 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5815 // Check interrupt before trying to wait
5816 if (Thread::is_interrupted(thread, false)) {
5817 return;
5818 }
5819
5820 // Next, demultiplex/decode time arguments
5821 timespec absTime;
5822 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
5823 return;
5824 }
5825 if (time > 0) {
5826 unpackTime(&absTime, isAbsolute, time);
5827 }
5828
5829
5830 // Enter safepoint region
5831 // Beware of deadlocks such as 6317397.
5832 // The per-thread Parker:: mutex is a classic leaf-lock.
5833 // In particular a thread must never block on the Threads_lock while
5834 // holding the Parker:: mutex. If safepoints are pending both the
5835 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5836 ThreadBlockInVM tbivm(jt);
5837
5838 // Don't wait if cannot get lock since interference arises from
5839 // unblocking. Also. check interrupt before trying wait
5840 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5841 return;
5842 }
5843
5844 int status;
5845 if (_counter > 0) { // no wait needed
5846 _counter = 0;
5847 status = pthread_mutex_unlock(_mutex);
5848 assert_status(status == 0, status, "invariant");
5849 // Paranoia to ensure our locked and lock-free paths interact
5850 // correctly with each other and Java-level accesses.
5851 OrderAccess::fence();
5852 return;
5853 }
5854
5855 #ifdef ASSERT
5856 // Don't catch signals while blocked; let the running threads have the signals.
5857 // (This allows a debugger to break into the running thread.)
5858 sigset_t oldsigs;
5859 sigemptyset(&oldsigs);
5860 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5861 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5862 #endif
5863
5864 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5865 jt->set_suspend_equivalent();
5866 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5867
5868 assert(_cur_index == -1, "invariant");
5869 if (time == 0) {
5870 _cur_index = REL_INDEX; // arbitrary choice when not timed
5871 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
5872 } else {
5873 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5874 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
5875 }
5876 _cur_index = -1;
5877 assert_status(status == 0 || status == EINTR ||
5878 status == ETIME || status == ETIMEDOUT,
5879 status, "cond_timedwait");
5880
5881 #ifdef ASSERT
5882 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5883 #endif
5884
5885 _counter = 0;
5886 status = pthread_mutex_unlock(_mutex);
5887 assert_status(status == 0, status, "invariant");
5888 // Paranoia to ensure our locked and lock-free paths interact
5889 // correctly with each other and Java-level accesses.
5890 OrderAccess::fence();
5891
5892 // If externally suspended while waiting, re-suspend
5893 if (jt->handle_special_suspend_equivalent_condition()) {
5894 jt->java_suspend_self();
5895 }
5896 }
5897
5898 void Parker::unpark() {
5899 int status = pthread_mutex_lock(_mutex);
5900 assert_status(status == 0, status, "invariant");
5901 const int s = _counter;
5902 _counter = 1;
5903 // must capture correct index before unlocking
5904 int index = _cur_index;
5905 status = pthread_mutex_unlock(_mutex);
5906 assert_status(status == 0, status, "invariant");
5907 if (s < 1 && index != -1) {
5908 // thread is definitely parked
5909 status = pthread_cond_signal(&_cond[index]);
5910 assert_status(status == 0, status, "invariant");
5911 }
5912 }
5913
5914
5915 extern char** environ;
5916
5917 // Run the specified command in a separate process. Return its exit value,
5918 // or -1 on failure (e.g. can't fork a new process).
5919 // Unlike system(), this function can be called from signal handler. It
5920 // doesn't block SIGINT et al.
5921 int os::fork_and_exec(char* cmd) {
5922 const char * argv[4] = {"sh", "-c", cmd, NULL};
5923
5924 pid_t pid = fork();
5925
5926 if (pid < 0) {
5927 // fork failed
5928 return -1;
5929
5930 } else if (pid == 0) {
5931 // child process
5932
5933 execve("/bin/sh", (char* const*)argv, environ);
5934
5935 // execve failed
5936 _exit(-1);
5937
5938 } else {
5939 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5940 // care about the actual exit code, for now.
5941
5942 int status;
5943
5944 // Wait for the child process to exit. This returns immediately if
5945 // the child has already exited. */
5946 while (waitpid(pid, &status, 0) < 0) {
5947 switch (errno) {
5948 case ECHILD: return 0;
5949 case EINTR: break;
5950 default: return -1;
5951 }
5952 }
5953
5954 if (WIFEXITED(status)) {
5955 // The child exited normally; get its exit code.
5956 return WEXITSTATUS(status);
5957 } else if (WIFSIGNALED(status)) {
5958 // The child exited because of a signal
5959 // The best value to return is 0x80 + signal number,
5960 // because that is what all Unix shells do, and because
5961 // it allows callers to distinguish between process exit and
5962 // process death by signal.
5963 return 0x80 + WTERMSIG(status);
5964 } else {
5965 // Unknown exit code; pass it through
5966 return status;
5967 }
5968 }
5969 }
5970
5971 // is_headless_jre()
5972 //
5973 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5974 // in order to report if we are running in a headless jre
5975 //
5976 // Since JDK8 xawt/libmawt.so was moved into the same directory
5977 // as libawt.so, and renamed libawt_xawt.so
5978 //
5979 bool os::is_headless_jre() {
5980 struct stat statbuf;
5981 char buf[MAXPATHLEN];
5982 char libmawtpath[MAXPATHLEN];
5983 const char *xawtstr = "/xawt/libmawt.so";
5984 const char *new_xawtstr = "/libawt_xawt.so";
5985 char *p;
5986
5987 // Get path to libjvm.so
5988 os::jvm_path(buf, sizeof(buf));
5989
5990 // Get rid of libjvm.so
5991 p = strrchr(buf, '/');
5992 if (p == NULL) {
5993 return false;
5994 } else {
5995 *p = '\0';
5996 }
5997
5998 // Get rid of client or server
5999 p = strrchr(buf, '/');
6000 if (p == NULL) {
6001 return false;
6002 } else {
6003 *p = '\0';
6004 }
6005
6006 // check xawt/libmawt.so
6007 strcpy(libmawtpath, buf);
6008 strcat(libmawtpath, xawtstr);
6009 if (::stat(libmawtpath, &statbuf) == 0) return false;
6010
6011 // check libawt_xawt.so
6012 strcpy(libmawtpath, buf);
6013 strcat(libmawtpath, new_xawtstr);
6014 if (::stat(libmawtpath, &statbuf) == 0) return false;
6015
6016 return true;
6017 }
6018
6019 // Get the default path to the core file
6020 // Returns the length of the string
6021 int os::get_core_path(char* buffer, size_t bufferSize) {
6022 /*
6023 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
6024 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
6025 */
6026 const int core_pattern_len = 129;
6027 char core_pattern[core_pattern_len] = {0};
6028
6029 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
6030 if (core_pattern_file == -1) {
6031 return -1;
6032 }
6033
6034 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
6035 ::close(core_pattern_file);
6036 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
6037 return -1;
6038 }
6039 if (core_pattern[ret-1] == '\n') {
6040 core_pattern[ret-1] = '\0';
6041 } else {
6042 core_pattern[ret] = '\0';
6043 }
6044
6045 char *pid_pos = strstr(core_pattern, "%p");
6046 int written;
6047
6048 if (core_pattern[0] == '/') {
6049 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
6050 } else {
6051 char cwd[PATH_MAX];
6052
6053 const char* p = get_current_directory(cwd, PATH_MAX);
6054 if (p == NULL) {
6055 return -1;
6056 }
6057
6058 if (core_pattern[0] == '|') {
6059 written = jio_snprintf(buffer, bufferSize,
6060 "\"%s\" (or dumping to %s/core.%d)",
6061 &core_pattern[1], p, current_process_id());
6062 } else {
6063 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
6064 }
6065 }
6066
6067 if (written < 0) {
6068 return -1;
6069 }
6070
6071 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
6072 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
6073
6074 if (core_uses_pid_file != -1) {
6075 char core_uses_pid = 0;
6076 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
6077 ::close(core_uses_pid_file);
6078
6079 if (core_uses_pid == '1') {
6080 jio_snprintf(buffer + written, bufferSize - written,
6081 ".%d", current_process_id());
6082 }
6083 }
6084 }
6085
6086 return strlen(buffer);
6087 }
6088
6089 bool os::start_debugging(char *buf, int buflen) {
6090 int len = (int)strlen(buf);
6091 char *p = &buf[len];
6092
6093 jio_snprintf(p, buflen-len,
6094 "\n\n"
6095 "Do you want to debug the problem?\n\n"
6096 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6097 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6098 "Otherwise, press RETURN to abort...",
6099 os::current_process_id(), os::current_process_id(),
6100 os::current_thread_id(), os::current_thread_id());
6101
6102 bool yes = os::message_box("Unexpected Error", buf);
6103
6104 if (yes) {
6105 // yes, user asked VM to launch debugger
6106 jio_snprintf(buf, sizeof(char)*buflen, "gdb /proc/%d/exe %d",
6107 os::current_process_id(), os::current_process_id());
6108
6109 os::fork_and_exec(buf);
6110 yes = false;
6111 }
6112 return yes;
6113 }
6114
6115 static inline struct timespec get_mtime(const char* filename) {
6116 struct stat st;
6117 int ret = os::stat(filename, &st);
6118 assert(ret == 0, "failed to stat() file '%s': %s", filename, strerror(errno));
6119 return st.st_mtim;
6120 }
6121
6122 int os::compare_file_modified_times(const char* file1, const char* file2) {
6123 struct timespec filetime1 = get_mtime(file1);
6124 struct timespec filetime2 = get_mtime(file2);
6125 int diff = filetime1.tv_sec - filetime2.tv_sec;
6126 if (diff == 0) {
6127 return filetime1.tv_nsec - filetime2.tv_nsec;
6128 }
6129 return diff;
6130 }
6131
6132 /////////////// Unit tests ///////////////
6133
6134 #ifndef PRODUCT
6135
6136 #define test_log(...) \
6137 do { \
6138 if (VerboseInternalVMTests) { \
6139 tty->print_cr(__VA_ARGS__); \
6140 tty->flush(); \
6141 } \
6142 } while (false)
6143
6144 class TestReserveMemorySpecial : AllStatic {
6145 public:
6146 static void small_page_write(void* addr, size_t size) {
6147 size_t page_size = os::vm_page_size();
6148
6149 char* end = (char*)addr + size;
6150 for (char* p = (char*)addr; p < end; p += page_size) {
6151 *p = 1;
6152 }
6153 }
6154
6155 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6156 if (!UseHugeTLBFS) {
6157 return;
6158 }
6159
6160 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6161
6162 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6163
6164 if (addr != NULL) {
6165 small_page_write(addr, size);
6166
6167 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6168 }
6169 }
6170
6171 static void test_reserve_memory_special_huge_tlbfs_only() {
6172 if (!UseHugeTLBFS) {
6173 return;
6174 }
6175
6176 size_t lp = os::large_page_size();
6177
6178 for (size_t size = lp; size <= lp * 10; size += lp) {
6179 test_reserve_memory_special_huge_tlbfs_only(size);
6180 }
6181 }
6182
6183 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6184 size_t lp = os::large_page_size();
6185 size_t ag = os::vm_allocation_granularity();
6186
6187 // sizes to test
6188 const size_t sizes[] = {
6189 lp, lp + ag, lp + lp / 2, lp * 2,
6190 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6191 lp * 10, lp * 10 + lp / 2
6192 };
6193 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6194
6195 // For each size/alignment combination, we test three scenarios:
6196 // 1) with req_addr == NULL
6197 // 2) with a non-null req_addr at which we expect to successfully allocate
6198 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6199 // expect the allocation to either fail or to ignore req_addr
6200
6201 // Pre-allocate two areas; they shall be as large as the largest allocation
6202 // and aligned to the largest alignment we will be testing.
6203 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6204 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6205 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6206 -1, 0);
6207 assert(mapping1 != MAP_FAILED, "should work");
6208
6209 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6210 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6211 -1, 0);
6212 assert(mapping2 != MAP_FAILED, "should work");
6213
6214 // Unmap the first mapping, but leave the second mapping intact: the first
6215 // mapping will serve as a value for a "good" req_addr (case 2). The second
6216 // mapping, still intact, as "bad" req_addr (case 3).
6217 ::munmap(mapping1, mapping_size);
6218
6219 // Case 1
6220 test_log("%s, req_addr NULL:", __FUNCTION__);
6221 test_log("size align result");
6222
6223 for (int i = 0; i < num_sizes; i++) {
6224 const size_t size = sizes[i];
6225 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6226 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6227 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6228 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6229 if (p != NULL) {
6230 assert(is_ptr_aligned(p, alignment), "must be");
6231 small_page_write(p, size);
6232 os::Linux::release_memory_special_huge_tlbfs(p, size);
6233 }
6234 }
6235 }
6236
6237 // Case 2
6238 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6239 test_log("size align req_addr result");
6240
6241 for (int i = 0; i < num_sizes; i++) {
6242 const size_t size = sizes[i];
6243 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6244 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6245 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6246 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6247 size, alignment, p2i(req_addr), p2i(p),
6248 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6249 if (p != NULL) {
6250 assert(p == req_addr, "must be");
6251 small_page_write(p, size);
6252 os::Linux::release_memory_special_huge_tlbfs(p, size);
6253 }
6254 }
6255 }
6256
6257 // Case 3
6258 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6259 test_log("size align req_addr result");
6260
6261 for (int i = 0; i < num_sizes; i++) {
6262 const size_t size = sizes[i];
6263 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6264 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6265 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6266 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6267 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6268 // as the area around req_addr contains already existing mappings, the API should always
6269 // return NULL (as per contract, it cannot return another address)
6270 assert(p == NULL, "must be");
6271 }
6272 }
6273
6274 ::munmap(mapping2, mapping_size);
6275
6276 }
6277
6278 static void test_reserve_memory_special_huge_tlbfs() {
6279 if (!UseHugeTLBFS) {
6280 return;
6281 }
6282
6283 test_reserve_memory_special_huge_tlbfs_only();
6284 test_reserve_memory_special_huge_tlbfs_mixed();
6285 }
6286
6287 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6288 if (!UseSHM) {
6289 return;
6290 }
6291
6292 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6293
6294 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6295
6296 if (addr != NULL) {
6297 assert(is_ptr_aligned(addr, alignment), "Check");
6298 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6299
6300 small_page_write(addr, size);
6301
6302 os::Linux::release_memory_special_shm(addr, size);
6303 }
6304 }
6305
6306 static void test_reserve_memory_special_shm() {
6307 size_t lp = os::large_page_size();
6308 size_t ag = os::vm_allocation_granularity();
6309
6310 for (size_t size = ag; size < lp * 3; size += ag) {
6311 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6312 test_reserve_memory_special_shm(size, alignment);
6313 }
6314 }
6315 }
6316
6317 static void test() {
6318 test_reserve_memory_special_huge_tlbfs();
6319 test_reserve_memory_special_shm();
6320 }
6321 };
6322
6323 void TestReserveMemorySpecial_test() {
6324 TestReserveMemorySpecial::test();
6325 }
6326
6327 #endif