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