1 /*
2 * Copyright (c) 1999, 2014, 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 "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/filemap.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/init.hpp"
47 #include "runtime/java.hpp"
48 #include "runtime/javaCalls.hpp"
49 #include "runtime/mutexLocker.hpp"
50 #include "runtime/objectMonitor.hpp"
51 #include "runtime/osThread.hpp"
52 #include "runtime/perfMemory.hpp"
53 #include "runtime/sharedRuntime.hpp"
54 #include "runtime/statSampler.hpp"
55 #include "runtime/stubRoutines.hpp"
56 #include "runtime/threadCritical.hpp"
57 #include "runtime/timer.hpp"
58 #include "services/attachListener.hpp"
59 #include "services/memTracker.hpp"
60 #include "services/runtimeService.hpp"
61 #include "thread_linux.inline.hpp"
62 #include "utilities/decoder.hpp"
63 #include "utilities/defaultStream.hpp"
64 #include "utilities/events.hpp"
65 #include "utilities/elfFile.hpp"
66 #include "utilities/growableArray.hpp"
67 #include "utilities/vmError.hpp"
68 #ifdef TARGET_ARCH_x86
69 # include "assembler_x86.inline.hpp"
70 # include "nativeInst_x86.hpp"
71 #endif
72 #ifdef TARGET_ARCH_aarch64
73 # include "assembler_aarch64.inline.hpp"
74 # include "nativeInst_aarch64.hpp"
75 #endif
76 #ifdef TARGET_ARCH_sparc
77 # include "assembler_sparc.inline.hpp"
78 # include "nativeInst_sparc.hpp"
79 #endif
80 #ifdef TARGET_ARCH_zero
81 # include "assembler_zero.inline.hpp"
82 # include "nativeInst_zero.hpp"
83 #endif
84 #ifdef TARGET_ARCH_arm
85 # include "assembler_arm.inline.hpp"
86 # include "nativeInst_arm.hpp"
87 #endif
88 #ifdef TARGET_ARCH_ppc
89 # include "assembler_ppc.inline.hpp"
90 # include "nativeInst_ppc.hpp"
91 #endif
92
93 // put OS-includes here
94 # include <sys/types.h>
95 # include <sys/mman.h>
96 # include <sys/stat.h>
97 # include <sys/select.h>
98 # include <pthread.h>
99 # include <signal.h>
100 # include <errno.h>
101 # include <dlfcn.h>
102 # include <stdio.h>
103 # include <unistd.h>
104 # include <sys/resource.h>
105 # include <pthread.h>
106 # include <sys/stat.h>
107 # include <sys/time.h>
108 # include <sys/times.h>
109 # include <sys/utsname.h>
110 # include <sys/socket.h>
111 # include <sys/wait.h>
112 # include <pwd.h>
113 # include <poll.h>
114 # include <semaphore.h>
115 # include <fcntl.h>
116 # include <string.h>
117 # include <syscall.h>
118 # include <sys/sysinfo.h>
119 # include <gnu/libc-version.h>
120 # include <sys/ipc.h>
121 # include <sys/shm.h>
122 # include <link.h>
123 # include <stdint.h>
124 # include <inttypes.h>
125 # include <sys/ioctl.h>
126
127 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
128 // getrusage() is prepared to handle the associated failure.
129 #ifndef RUSAGE_THREAD
130 #define RUSAGE_THREAD (1) /* only the calling thread */
131 #endif
132
133 #define MAX_PATH (2 * K)
134
135 #define MAX_SECS 100000000
136
137 // for timer info max values which include all bits
138 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
139
140 #define LARGEPAGES_BIT (1 << 6)
141
142 #ifndef EM_AARCH64
143 #define EM_AARCH64 183 /* ARM AARCH64 */
144 #endif
145
146 ////////////////////////////////////////////////////////////////////////////////
147 // global variables
148 julong os::Linux::_physical_memory = 0;
149
150 address os::Linux::_initial_thread_stack_bottom = NULL;
151 uintptr_t os::Linux::_initial_thread_stack_size = 0;
152
153 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
154 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
155 Mutex* os::Linux::_createThread_lock = NULL;
156 pthread_t os::Linux::_main_thread;
157 int os::Linux::_page_size = -1;
158 const int os::Linux::_vm_default_page_size = (8 * K);
159 bool os::Linux::_is_floating_stack = false;
160 bool os::Linux::_is_NPTL = false;
161 bool os::Linux::_supports_fast_thread_cpu_time = false;
162 const char * os::Linux::_glibc_version = NULL;
163 const char * os::Linux::_libpthread_version = NULL;
164 pthread_condattr_t os::Linux::_condattr[1];
165
166 static jlong initial_time_count=0;
167
168 static int clock_tics_per_sec = 100;
169
170 // For diagnostics to print a message once. see run_periodic_checks
171 static sigset_t check_signal_done;
172 static bool check_signals = true;
173
174 static pid_t _initial_pid = 0;
175
176 /* Signal number used to suspend/resume a thread */
177
178 /* do not use any signal number less than SIGSEGV, see 4355769 */
179 static int SR_signum = SIGUSR2;
180 sigset_t SR_sigset;
181
182 /* Used to protect dlsym() calls */
183 static pthread_mutex_t dl_mutex;
184
185 // Declarations
186 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
187
188 #ifdef JAVASE_EMBEDDED
189 class MemNotifyThread: public Thread {
190 friend class VMStructs;
191 public:
192 virtual void run();
193
194 private:
195 static MemNotifyThread* _memnotify_thread;
196 int _fd;
197
198 public:
199
200 // Constructor
201 MemNotifyThread(int fd);
202
203 // Tester
204 bool is_memnotify_thread() const { return true; }
205
206 // Printing
207 char* name() const { return (char*)"Linux MemNotify Thread"; }
208
209 // Returns the single instance of the MemNotifyThread
210 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
211
212 // Create and start the single instance of MemNotifyThread
213 static void start();
214 };
215 #endif // JAVASE_EMBEDDED
216
217 // utility functions
218
219 static int SR_initialize();
220 static int SR_finalize();
221
222 julong os::available_memory() {
223 return Linux::available_memory();
224 }
225
226 julong os::Linux::available_memory() {
227 // values in struct sysinfo are "unsigned long"
228 struct sysinfo si;
229 sysinfo(&si);
230
231 return (julong)si.freeram * si.mem_unit;
232 }
233
234 julong os::physical_memory() {
235 return Linux::physical_memory();
236 }
237
238 julong os::allocatable_physical_memory(julong size) {
239 #ifdef _LP64
240 return size;
241 #else
242 julong result = MIN2(size, (julong)3800*M);
243 if (!is_allocatable(result)) {
244 // See comments under solaris for alignment considerations
245 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
246 result = MIN2(size, reasonable_size);
247 }
248 return result;
249 #endif // _LP64
250 }
251
252 ////////////////////////////////////////////////////////////////////////////////
253 // environment support
254
255 bool os::getenv(const char* name, char* buf, int len) {
256 const char* val = ::getenv(name);
257 if (val != NULL && strlen(val) < (size_t)len) {
258 strcpy(buf, val);
259 return true;
260 }
261 if (len > 0) buf[0] = 0; // return a null string
262 return false;
263 }
264
265
266 // Return true if user is running as root.
267
268 bool os::have_special_privileges() {
269 static bool init = false;
270 static bool privileges = false;
271 if (!init) {
272 privileges = (getuid() != geteuid()) || (getgid() != getegid());
273 init = true;
274 }
275 return privileges;
276 }
277
278
279 #ifndef SYS_gettid
280 // i386: 224, ia64: 1105, amd64: 186, sparc 143
281 #ifdef __ia64__
282 #define SYS_gettid 1105
283 #elif __i386__
284 #define SYS_gettid 224
285 #elif __amd64__
286 #define SYS_gettid 186
287 #elif __sparc__
288 #define SYS_gettid 143
289 #else
290 #error define gettid for the arch
291 #endif
292 #endif
293
294 // Cpu architecture string
295 #if defined(ZERO)
296 static char cpu_arch[] = ZERO_LIBARCH;
297 #elif defined(IA64)
298 static char cpu_arch[] = "ia64";
299 #elif defined(IA32)
300 static char cpu_arch[] = "i386";
301 #elif defined(AMD64)
302 static char cpu_arch[] = "amd64";
303 #elif defined(ARM)
304 static char cpu_arch[] = "arm";
305 #elif defined(PPC32)
306 static char cpu_arch[] = "ppc";
307 #elif defined(PPC64)
308 static char cpu_arch[] = "ppc64";
309 #elif defined(SPARC)
310 # ifdef _LP64
311 static char cpu_arch[] = "sparcv9";
312 # else
313 static char cpu_arch[] = "sparc";
314 # endif
315 #elif defined(AARCH64)
316 static char cpu_arch[] = "aarch64";
317 #else
318 #error Add appropriate cpu_arch setting
319 #endif
320
321
322 // pid_t gettid()
323 //
324 // Returns the kernel thread id of the currently running thread. Kernel
325 // thread id is used to access /proc.
326 //
327 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
328 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
329 //
330 pid_t os::Linux::gettid() {
331 int rslt = syscall(SYS_gettid);
332 if (rslt == -1) {
333 // old kernel, no NPTL support
334 return getpid();
335 } else {
336 return (pid_t)rslt;
337 }
338 }
339
340 // Most versions of linux have a bug where the number of processors are
341 // determined by looking at the /proc file system. In a chroot environment,
342 // the system call returns 1. This causes the VM to act as if it is
343 // a single processor and elide locking (see is_MP() call).
344 static bool unsafe_chroot_detected = false;
345 static const char *unstable_chroot_error = "/proc file system not found.\n"
346 "Java may be unstable running multithreaded in a chroot "
347 "environment on Linux when /proc filesystem is not mounted.";
348
349 void os::Linux::initialize_system_info() {
350 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
351 if (processor_count() == 1) {
352 pid_t pid = os::Linux::gettid();
353 char fname[32];
354 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
355 FILE *fp = fopen(fname, "r");
356 if (fp == NULL) {
357 unsafe_chroot_detected = true;
358 } else {
359 fclose(fp);
360 }
361 }
362 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
363 assert(processor_count() > 0, "linux error");
364 }
365
366 void os::init_system_properties_values() {
367 // char arch[12];
368 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
369
370 // The next steps are taken in the product version:
371 //
372 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
373 // This library should be located at:
374 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
375 //
376 // If "/jre/lib/" appears at the right place in the path, then we
377 // assume libjvm[_g].so is installed in a JDK and we use this path.
378 //
379 // Otherwise exit with message: "Could not create the Java virtual machine."
380 //
381 // The following extra steps are taken in the debugging version:
382 //
383 // If "/jre/lib/" does NOT appear at the right place in the path
384 // instead of exit check for $JAVA_HOME environment variable.
385 //
386 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
387 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
388 // it looks like libjvm[_g].so is installed there
389 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
390 //
391 // Otherwise exit.
392 //
393 // Important note: if the location of libjvm.so changes this
394 // code needs to be changed accordingly.
395
396 // The next few definitions allow the code to be verbatim:
397 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
398 #define getenv(n) ::getenv(n)
399
400 /*
401 * See ld(1):
402 * The linker uses the following search paths to locate required
403 * shared libraries:
404 * 1: ...
405 * ...
406 * 7: The default directories, normally /lib and /usr/lib.
407 */
408 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390) || defined(AARCH64)) || defined(BUILTIN_SIM)
409 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
410 #else
411 #define DEFAULT_LIBPATH "/lib:/usr/lib"
412 #endif
413
414 #define EXTENSIONS_DIR "/lib/ext"
415 #define ENDORSED_DIR "/lib/endorsed"
416 #define REG_DIR "/usr/java/packages"
417
418 {
419 /* sysclasspath, java_home, dll_dir */
420 {
421 char *home_path;
422 char *dll_path;
423 char *pslash;
424 char buf[MAXPATHLEN];
425 os::jvm_path(buf, sizeof(buf));
426
427 // Found the full path to libjvm.so.
428 // Now cut the path to <java_home>/jre if we can.
429 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
430 pslash = strrchr(buf, '/');
431 if (pslash != NULL)
432 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
433 dll_path = malloc(strlen(buf) + 1);
434 if (dll_path == NULL)
435 return;
436 strcpy(dll_path, buf);
437 Arguments::set_dll_dir(dll_path);
438
439 if (pslash != NULL) {
440 pslash = strrchr(buf, '/');
441 if (pslash != NULL) {
442 *pslash = '\0'; /* get rid of /<arch> */
443 pslash = strrchr(buf, '/');
444 if (pslash != NULL)
445 *pslash = '\0'; /* get rid of /lib */
446 }
447 }
448
449 home_path = malloc(strlen(buf) + 1);
450 if (home_path == NULL)
451 return;
452 strcpy(home_path, buf);
453 Arguments::set_java_home(home_path);
454
455 if (!set_boot_path('/', ':'))
456 return;
457 }
458
459 /*
460 * Where to look for native libraries
461 *
462 * Note: Due to a legacy implementation, most of the library path
463 * is set in the launcher. This was to accomodate linking restrictions
464 * on legacy Linux implementations (which are no longer supported).
465 * Eventually, all the library path setting will be done here.
466 *
467 * However, to prevent the proliferation of improperly built native
468 * libraries, the new path component /usr/java/packages is added here.
469 * Eventually, all the library path setting will be done here.
470 */
471 {
472 char *ld_library_path;
473
474 /*
475 * Construct the invariant part of ld_library_path. Note that the
476 * space for the colon and the trailing null are provided by the
477 * nulls included by the sizeof operator (so actually we allocate
478 * a byte more than necessary).
479 */
480 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
481 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
482 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
483
484 /*
485 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
486 * should always exist (until the legacy problem cited above is
487 * addressed).
488 */
489 char *v = getenv("LD_LIBRARY_PATH");
490 if (v != NULL) {
491 char *t = ld_library_path;
492 /* That's +1 for the colon and +1 for the trailing '\0' */
493 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
494 sprintf(ld_library_path, "%s:%s", v, t);
495 }
496 Arguments::set_library_path(ld_library_path);
497 }
498
499 /*
500 * Extensions directories.
501 *
502 * Note that the space for the colon and the trailing null are provided
503 * by the nulls included by the sizeof operator (so actually one byte more
504 * than necessary is allocated).
505 */
506 {
507 char *buf = malloc(strlen(Arguments::get_java_home()) +
508 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
509 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
510 Arguments::get_java_home());
511 Arguments::set_ext_dirs(buf);
512 }
513
514 /* Endorsed standards default directory. */
515 {
516 char * buf;
517 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
518 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
519 Arguments::set_endorsed_dirs(buf);
520 }
521 }
522
523 #undef malloc
524 #undef getenv
525 #undef EXTENSIONS_DIR
526 #undef ENDORSED_DIR
527
528 // Done
529 return;
530 }
531
532 ////////////////////////////////////////////////////////////////////////////////
533 // breakpoint support
534
535 void os::breakpoint() {
536 BREAKPOINT;
537 }
538
539 extern "C" void breakpoint() {
540 // use debugger to set breakpoint here
541 }
542
543 ////////////////////////////////////////////////////////////////////////////////
544 // signal support
545
546 debug_only(static bool signal_sets_initialized = false);
547 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
548
549 bool os::Linux::is_sig_ignored(int sig) {
550 struct sigaction oact;
551 sigaction(sig, (struct sigaction*)NULL, &oact);
552 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
553 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
554 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
555 return true;
556 else
557 return false;
558 }
559
560 void os::Linux::signal_sets_init() {
561 // Should also have an assertion stating we are still single-threaded.
562 assert(!signal_sets_initialized, "Already initialized");
563 // Fill in signals that are necessarily unblocked for all threads in
564 // the VM. Currently, we unblock the following signals:
565 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
566 // by -Xrs (=ReduceSignalUsage));
567 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
568 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
569 // the dispositions or masks wrt these signals.
570 // Programs embedding the VM that want to use the above signals for their
571 // own purposes must, at this time, use the "-Xrs" option to prevent
572 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
573 // (See bug 4345157, and other related bugs).
574 // In reality, though, unblocking these signals is really a nop, since
575 // these signals are not blocked by default.
576 sigemptyset(&unblocked_sigs);
577 sigemptyset(&allowdebug_blocked_sigs);
578 sigaddset(&unblocked_sigs, SIGILL);
579 sigaddset(&unblocked_sigs, SIGSEGV);
580 sigaddset(&unblocked_sigs, SIGBUS);
581 sigaddset(&unblocked_sigs, SIGFPE);
582 #if defined(PPC64)
583 sigaddset(&unblocked_sigs, SIGTRAP);
584 #endif
585 sigaddset(&unblocked_sigs, SR_signum);
586
587 if (!ReduceSignalUsage) {
588 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
589 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
590 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
591 }
592 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
593 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
594 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
595 }
596 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
597 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
598 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
599 }
600 }
601 // Fill in signals that are blocked by all but the VM thread.
602 sigemptyset(&vm_sigs);
603 if (!ReduceSignalUsage)
604 sigaddset(&vm_sigs, BREAK_SIGNAL);
605 debug_only(signal_sets_initialized = true);
606
607 }
608
609 // These are signals that are unblocked while a thread is running Java.
610 // (For some reason, they get blocked by default.)
611 sigset_t* os::Linux::unblocked_signals() {
612 assert(signal_sets_initialized, "Not initialized");
613 return &unblocked_sigs;
614 }
615
616 // These are the signals that are blocked while a (non-VM) thread is
617 // running Java. Only the VM thread handles these signals.
618 sigset_t* os::Linux::vm_signals() {
619 assert(signal_sets_initialized, "Not initialized");
620 return &vm_sigs;
621 }
622
623 // These are signals that are blocked during cond_wait to allow debugger in
624 sigset_t* os::Linux::allowdebug_blocked_signals() {
625 assert(signal_sets_initialized, "Not initialized");
626 return &allowdebug_blocked_sigs;
627 }
628
629 void os::Linux::hotspot_sigmask(Thread* thread) {
630
631 //Save caller's signal mask before setting VM signal mask
632 sigset_t caller_sigmask;
633 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
634
635 OSThread* osthread = thread->osthread();
636 osthread->set_caller_sigmask(caller_sigmask);
637
638 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
639
640 if (!ReduceSignalUsage) {
641 if (thread->is_VM_thread()) {
642 // Only the VM thread handles BREAK_SIGNAL ...
643 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
644 } else {
645 // ... all other threads block BREAK_SIGNAL
646 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
647 }
648 }
649 }
650
651 //////////////////////////////////////////////////////////////////////////////
652 // detecting pthread library
653
654 void os::Linux::libpthread_init() {
655 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
656 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
657 // generic name for earlier versions.
658 // Define macros here so we can build HotSpot on old systems.
659 # ifndef _CS_GNU_LIBC_VERSION
660 # define _CS_GNU_LIBC_VERSION 2
661 # endif
662 # ifndef _CS_GNU_LIBPTHREAD_VERSION
663 # define _CS_GNU_LIBPTHREAD_VERSION 3
664 # endif
665
666 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
667 if (n > 0) {
668 char *str = (char *)malloc(n, mtInternal);
669 confstr(_CS_GNU_LIBC_VERSION, str, n);
670 os::Linux::set_glibc_version(str);
671 } else {
672 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
673 static char _gnu_libc_version[32];
674 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
675 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
676 os::Linux::set_glibc_version(_gnu_libc_version);
677 }
678
679 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
680 if (n > 0) {
681 char *str = (char *)malloc(n, mtInternal);
682 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
683 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
684 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
685 // is the case. LinuxThreads has a hard limit on max number of threads.
686 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
687 // On the other hand, NPTL does not have such a limit, sysconf()
688 // will return -1 and errno is not changed. Check if it is really NPTL.
689 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
690 strstr(str, "NPTL") &&
691 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
692 free(str);
693 os::Linux::set_libpthread_version("linuxthreads");
694 } else {
695 os::Linux::set_libpthread_version(str);
696 }
697 } else {
698 // glibc before 2.3.2 only has LinuxThreads.
699 os::Linux::set_libpthread_version("linuxthreads");
700 }
701
702 if (strstr(libpthread_version(), "NPTL")) {
703 os::Linux::set_is_NPTL();
704 } else {
705 os::Linux::set_is_LinuxThreads();
706 }
707
708 // LinuxThreads have two flavors: floating-stack mode, which allows variable
709 // stack size; and fixed-stack mode. NPTL is always floating-stack.
710 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
711 os::Linux::set_is_floating_stack();
712 }
713 }
714
715 /////////////////////////////////////////////////////////////////////////////
716 // thread stack
717
718 // Force Linux kernel to expand current thread stack. If "bottom" is close
719 // to the stack guard, caller should block all signals.
720 //
721 // MAP_GROWSDOWN:
722 // A special mmap() flag that is used to implement thread stacks. It tells
723 // kernel that the memory region should extend downwards when needed. This
724 // allows early versions of LinuxThreads to only mmap the first few pages
725 // when creating a new thread. Linux kernel will automatically expand thread
726 // stack as needed (on page faults).
727 //
728 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
729 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
730 // region, it's hard to tell if the fault is due to a legitimate stack
731 // access or because of reading/writing non-exist memory (e.g. buffer
732 // overrun). As a rule, if the fault happens below current stack pointer,
733 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
734 // application (see Linux kernel fault.c).
735 //
736 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
737 // stack overflow detection.
738 //
739 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
740 // not use this flag. However, the stack of initial thread is not created
741 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
742 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
743 // and then attach the thread to JVM.
744 //
745 // To get around the problem and allow stack banging on Linux, we need to
746 // manually expand thread stack after receiving the SIGSEGV.
747 //
748 // There are two ways to expand thread stack to address "bottom", we used
749 // both of them in JVM before 1.5:
750 // 1. adjust stack pointer first so that it is below "bottom", and then
751 // touch "bottom"
752 // 2. mmap() the page in question
753 //
754 // Now alternate signal stack is gone, it's harder to use 2. For instance,
755 // if current sp is already near the lower end of page 101, and we need to
756 // call mmap() to map page 100, it is possible that part of the mmap() frame
757 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
758 // That will destroy the mmap() frame and cause VM to crash.
759 //
760 // The following code works by adjusting sp first, then accessing the "bottom"
761 // page to force a page fault. Linux kernel will then automatically expand the
762 // stack mapping.
763 //
764 // _expand_stack_to() assumes its frame size is less than page size, which
765 // should always be true if the function is not inlined.
766
767 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
768 #define NOINLINE
769 #else
770 #define NOINLINE __attribute__ ((noinline))
771 #endif
772
773 static void _expand_stack_to(address bottom) NOINLINE;
774
775 static void _expand_stack_to(address bottom) {
776 address sp;
777 size_t size;
778 volatile char *p;
779
780 // Adjust bottom to point to the largest address within the same page, it
781 // gives us a one-page buffer if alloca() allocates slightly more memory.
782 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
783 bottom += os::Linux::page_size() - 1;
784
785 // sp might be slightly above current stack pointer; if that's the case, we
786 // will alloca() a little more space than necessary, which is OK. Don't use
787 // os::current_stack_pointer(), as its result can be slightly below current
788 // stack pointer, causing us to not alloca enough to reach "bottom".
789 sp = (address)&sp;
790
791 if (sp > bottom) {
792 size = sp - bottom;
793 p = (volatile char *)alloca(size);
794 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
795 p[0] = '\0';
796 }
797 }
798
799 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
800 assert(t!=NULL, "just checking");
801 assert(t->osthread()->expanding_stack(), "expand should be set");
802 assert(t->stack_base() != NULL, "stack_base was not initialized");
803
804 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
805 sigset_t mask_all, old_sigset;
806 sigfillset(&mask_all);
807 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
808 _expand_stack_to(addr);
809 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
810 return true;
811 }
812 return false;
813 }
814
815 //////////////////////////////////////////////////////////////////////////////
816 // create new thread
817
818 static address highest_vm_reserved_address();
819
820 // check if it's safe to start a new thread
821 static bool _thread_safety_check(Thread* thread) {
822 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
823 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
824 // Heap is mmap'ed at lower end of memory space. Thread stacks are
825 // allocated (MAP_FIXED) from high address space. Every thread stack
826 // occupies a fixed size slot (usually 2Mbytes, but user can change
827 // it to other values if they rebuild LinuxThreads).
828 //
829 // Problem with MAP_FIXED is that mmap() can still succeed even part of
830 // the memory region has already been mmap'ed. That means if we have too
831 // many threads and/or very large heap, eventually thread stack will
832 // collide with heap.
833 //
834 // Here we try to prevent heap/stack collision by comparing current
835 // stack bottom with the highest address that has been mmap'ed by JVM
836 // plus a safety margin for memory maps created by native code.
837 //
838 // This feature can be disabled by setting ThreadSafetyMargin to 0
839 //
840 if (ThreadSafetyMargin > 0) {
841 address stack_bottom = os::current_stack_base() - os::current_stack_size();
842
843 // not safe if our stack extends below the safety margin
844 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
845 } else {
846 return true;
847 }
848 } else {
849 // Floating stack LinuxThreads or NPTL:
850 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
851 // there's not enough space left, pthread_create() will fail. If we come
852 // here, that means enough space has been reserved for stack.
853 return true;
854 }
855 }
856
857 // Thread start routine for all newly created threads
858 static void *java_start(Thread *thread) {
859 // Try to randomize the cache line index of hot stack frames.
860 // This helps when threads of the same stack traces evict each other's
861 // cache lines. The threads can be either from the same JVM instance, or
862 // from different JVM instances. The benefit is especially true for
863 // processors with hyperthreading technology.
864 static int counter = 0;
865 int pid = os::current_process_id();
866 alloca(((pid ^ counter++) & 7) * 128);
867
868 ThreadLocalStorage::set_thread(thread);
869
870 OSThread* osthread = thread->osthread();
871 Monitor* sync = osthread->startThread_lock();
872
873 // non floating stack LinuxThreads needs extra check, see above
874 if (!_thread_safety_check(thread)) {
875 // notify parent thread
876 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
877 osthread->set_state(ZOMBIE);
878 sync->notify_all();
879 return NULL;
880 }
881
882 // thread_id is kernel thread id (similar to Solaris LWP id)
883 osthread->set_thread_id(os::Linux::gettid());
884
885 if (UseNUMA) {
886 int lgrp_id = os::numa_get_group_id();
887 if (lgrp_id != -1) {
888 thread->set_lgrp_id(lgrp_id);
889 }
890 }
891 // initialize signal mask for this thread
892 os::Linux::hotspot_sigmask(thread);
893
894 // initialize floating point control register
895 os::Linux::init_thread_fpu_state();
896
897 // handshaking with parent thread
898 {
899 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
900
901 // notify parent thread
902 osthread->set_state(INITIALIZED);
903 sync->notify_all();
904
905 // wait until os::start_thread()
906 while (osthread->get_state() == INITIALIZED) {
907 sync->wait(Mutex::_no_safepoint_check_flag);
908 }
909 }
910
911 // call one more level start routine
912 thread->run();
913
914 return 0;
915 }
916
917 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
918 assert(thread->osthread() == NULL, "caller responsible");
919
920 // Allocate the OSThread object
921 OSThread* osthread = new OSThread(NULL, NULL);
922 if (osthread == NULL) {
923 return false;
924 }
925
926 // set the correct thread state
927 osthread->set_thread_type(thr_type);
928
929 // Initial state is ALLOCATED but not INITIALIZED
930 osthread->set_state(ALLOCATED);
931
932 thread->set_osthread(osthread);
933
934 // init thread attributes
935 pthread_attr_t attr;
936 pthread_attr_init(&attr);
937 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
938
939 // stack size
940 if (os::Linux::supports_variable_stack_size()) {
941 // calculate stack size if it's not specified by caller
942 if (stack_size == 0) {
943 stack_size = os::Linux::default_stack_size(thr_type);
944
945 switch (thr_type) {
946 case os::java_thread:
947 // Java threads use ThreadStackSize which default value can be
948 // changed with the flag -Xss
949 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
950 stack_size = JavaThread::stack_size_at_create();
951 break;
952 case os::compiler_thread:
953 if (CompilerThreadStackSize > 0) {
954 stack_size = (size_t)(CompilerThreadStackSize * K);
955 break;
956 } // else fall through:
957 // use VMThreadStackSize if CompilerThreadStackSize is not defined
958 case os::vm_thread:
959 case os::pgc_thread:
960 case os::cgc_thread:
961 case os::watcher_thread:
962 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
963 break;
964 }
965 }
966
967 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
968 pthread_attr_setstacksize(&attr, stack_size);
969 } else {
970 // let pthread_create() pick the default value.
971 }
972
973 // glibc guard page
974 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
975
976 ThreadState state;
977
978 {
979 // Serialize thread creation if we are running with fixed stack LinuxThreads
980 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
981 if (lock) {
982 os::Linux::createThread_lock()->lock_without_safepoint_check();
983 }
984
985 pthread_t tid;
986 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
987
988 pthread_attr_destroy(&attr);
989
990 if (ret != 0) {
991 if (PrintMiscellaneous && (Verbose || WizardMode)) {
992 perror("pthread_create()");
993 }
994 // Need to clean up stuff we've allocated so far
995 thread->set_osthread(NULL);
996 delete osthread;
997 if (lock) os::Linux::createThread_lock()->unlock();
998 return false;
999 }
1000
1001 // Store pthread info into the OSThread
1002 osthread->set_pthread_id(tid);
1003
1004 // Wait until child thread is either initialized or aborted
1005 {
1006 Monitor* sync_with_child = osthread->startThread_lock();
1007 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1008 while ((state = osthread->get_state()) == ALLOCATED) {
1009 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
1010 }
1011 }
1012
1013 if (lock) {
1014 os::Linux::createThread_lock()->unlock();
1015 }
1016 }
1017
1018 // Aborted due to thread limit being reached
1019 if (state == ZOMBIE) {
1020 thread->set_osthread(NULL);
1021 delete osthread;
1022 return false;
1023 }
1024
1025 // The thread is returned suspended (in state INITIALIZED),
1026 // and is started higher up in the call chain
1027 assert(state == INITIALIZED, "race condition");
1028 return true;
1029 }
1030
1031 /////////////////////////////////////////////////////////////////////////////
1032 // attach existing thread
1033
1034 // bootstrap the main thread
1035 bool os::create_main_thread(JavaThread* thread) {
1036 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1037 return create_attached_thread(thread);
1038 }
1039
1040 bool os::create_attached_thread(JavaThread* thread) {
1041 #ifdef ASSERT
1042 thread->verify_not_published();
1043 #endif
1044
1045 // Allocate the OSThread object
1046 OSThread* osthread = new OSThread(NULL, NULL);
1047
1048 if (osthread == NULL) {
1049 return false;
1050 }
1051
1052 // Store pthread info into the OSThread
1053 osthread->set_thread_id(os::Linux::gettid());
1054 osthread->set_pthread_id(::pthread_self());
1055
1056 // initialize floating point control register
1057 os::Linux::init_thread_fpu_state();
1058
1059 // Initial thread state is RUNNABLE
1060 osthread->set_state(RUNNABLE);
1061
1062 thread->set_osthread(osthread);
1063
1064 if (UseNUMA) {
1065 int lgrp_id = os::numa_get_group_id();
1066 if (lgrp_id != -1) {
1067 thread->set_lgrp_id(lgrp_id);
1068 }
1069 }
1070
1071 if (os::Linux::is_initial_thread()) {
1072 // If current thread is initial thread, its stack is mapped on demand,
1073 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1074 // the entire stack region to avoid SEGV in stack banging.
1075 // It is also useful to get around the heap-stack-gap problem on SuSE
1076 // kernel (see 4821821 for details). We first expand stack to the top
1077 // of yellow zone, then enable stack yellow zone (order is significant,
1078 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1079 // is no gap between the last two virtual memory regions.
1080
1081 JavaThread *jt = (JavaThread *)thread;
1082 address addr = jt->stack_yellow_zone_base();
1083 assert(addr != NULL, "initialization problem?");
1084 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1085
1086 osthread->set_expanding_stack();
1087 os::Linux::manually_expand_stack(jt, addr);
1088 osthread->clear_expanding_stack();
1089 }
1090
1091 // initialize signal mask for this thread
1092 // and save the caller's signal mask
1093 os::Linux::hotspot_sigmask(thread);
1094
1095 return true;
1096 }
1097
1098 void os::pd_start_thread(Thread* thread) {
1099 OSThread * osthread = thread->osthread();
1100 assert(osthread->get_state() != INITIALIZED, "just checking");
1101 Monitor* sync_with_child = osthread->startThread_lock();
1102 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1103 sync_with_child->notify();
1104 }
1105
1106 // Free Linux resources related to the OSThread
1107 void os::free_thread(OSThread* osthread) {
1108 assert(osthread != NULL, "osthread not set");
1109
1110 if (Thread::current()->osthread() == osthread) {
1111 // Restore caller's signal mask
1112 sigset_t sigmask = osthread->caller_sigmask();
1113 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1114 }
1115
1116 delete osthread;
1117 }
1118
1119 //////////////////////////////////////////////////////////////////////////////
1120 // thread local storage
1121
1122 // Restore the thread pointer if the destructor is called. This is in case
1123 // someone from JNI code sets up a destructor with pthread_key_create to run
1124 // detachCurrentThread on thread death. Unless we restore the thread pointer we
1125 // will hang or crash. When detachCurrentThread is called the key will be set
1126 // to null and we will not be called again. If detachCurrentThread is never
1127 // called we could loop forever depending on the pthread implementation.
1128 static void restore_thread_pointer(void* p) {
1129 Thread* thread = (Thread*) p;
1130 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
1131 }
1132
1133 int os::allocate_thread_local_storage() {
1134 pthread_key_t key;
1135 int rslt = pthread_key_create(&key, restore_thread_pointer);
1136 assert(rslt == 0, "cannot allocate thread local storage");
1137 return (int)key;
1138 }
1139
1140 // Note: This is currently not used by VM, as we don't destroy TLS key
1141 // on VM exit.
1142 void os::free_thread_local_storage(int index) {
1143 int rslt = pthread_key_delete((pthread_key_t)index);
1144 assert(rslt == 0, "invalid index");
1145 }
1146
1147 void os::thread_local_storage_at_put(int index, void* value) {
1148 int rslt = pthread_setspecific((pthread_key_t)index, value);
1149 assert(rslt == 0, "pthread_setspecific failed");
1150 }
1151
1152 extern "C" Thread* get_thread() {
1153 return ThreadLocalStorage::thread();
1154 }
1155
1156 //////////////////////////////////////////////////////////////////////////////
1157 // initial thread
1158
1159 // Check if current thread is the initial thread, similar to Solaris thr_main.
1160 bool os::Linux::is_initial_thread(void) {
1161 char dummy;
1162 // If called before init complete, thread stack bottom will be null.
1163 // Can be called if fatal error occurs before initialization.
1164 if (initial_thread_stack_bottom() == NULL) return false;
1165 assert(initial_thread_stack_bottom() != NULL &&
1166 initial_thread_stack_size() != 0,
1167 "os::init did not locate initial thread's stack region");
1168 if ((address)&dummy >= initial_thread_stack_bottom() &&
1169 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1170 return true;
1171 else return false;
1172 }
1173
1174 // Find the virtual memory area that contains addr
1175 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1176 FILE *fp = fopen("/proc/self/maps", "r");
1177 if (fp) {
1178 address low, high;
1179 while (!feof(fp)) {
1180 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1181 if (low <= addr && addr < high) {
1182 if (vma_low) *vma_low = low;
1183 if (vma_high) *vma_high = high;
1184 fclose (fp);
1185 return true;
1186 }
1187 }
1188 for (;;) {
1189 int ch = fgetc(fp);
1190 if (ch == EOF || ch == (int)'\n') break;
1191 }
1192 }
1193 fclose(fp);
1194 }
1195 return false;
1196 }
1197
1198 // Locate initial thread stack. This special handling of initial thread stack
1199 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1200 // bogus value for initial thread.
1201 void os::Linux::capture_initial_stack(size_t max_size) {
1202 // stack size is the easy part, get it from RLIMIT_STACK
1203 size_t stack_size;
1204 struct rlimit rlim;
1205 getrlimit(RLIMIT_STACK, &rlim);
1206 stack_size = rlim.rlim_cur;
1207
1208 // 6308388: a bug in ld.so will relocate its own .data section to the
1209 // lower end of primordial stack; reduce ulimit -s value a little bit
1210 // so we won't install guard page on ld.so's data section.
1211 stack_size -= 2 * page_size();
1212
1213 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1214 // 7.1, in both cases we will get 2G in return value.
1215 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1216 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1217 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1218 // in case other parts in glibc still assumes 2M max stack size.
1219 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1220 #ifndef IA64
1221 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1222 #else
1223 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1224 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1225 #endif
1226
1227 // Try to figure out where the stack base (top) is. This is harder.
1228 //
1229 // When an application is started, glibc saves the initial stack pointer in
1230 // a global variable "__libc_stack_end", which is then used by system
1231 // libraries. __libc_stack_end should be pretty close to stack top. The
1232 // variable is available since the very early days. However, because it is
1233 // a private interface, it could disappear in the future.
1234 //
1235 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1236 // to __libc_stack_end, it is very close to stack top, but isn't the real
1237 // stack top. Note that /proc may not exist if VM is running as a chroot
1238 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1239 // /proc/<pid>/stat could change in the future (though unlikely).
1240 //
1241 // We try __libc_stack_end first. If that doesn't work, look for
1242 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1243 // as a hint, which should work well in most cases.
1244
1245 uintptr_t stack_start;
1246
1247 // try __libc_stack_end first
1248 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1249 if (p && *p) {
1250 stack_start = *p;
1251 } else {
1252 // see if we can get the start_stack field from /proc/self/stat
1253 FILE *fp;
1254 int pid;
1255 char state;
1256 int ppid;
1257 int pgrp;
1258 int session;
1259 int nr;
1260 int tpgrp;
1261 unsigned long flags;
1262 unsigned long minflt;
1263 unsigned long cminflt;
1264 unsigned long majflt;
1265 unsigned long cmajflt;
1266 unsigned long utime;
1267 unsigned long stime;
1268 long cutime;
1269 long cstime;
1270 long prio;
1271 long nice;
1272 long junk;
1273 long it_real;
1274 uintptr_t start;
1275 uintptr_t vsize;
1276 intptr_t rss;
1277 uintptr_t rsslim;
1278 uintptr_t scodes;
1279 uintptr_t ecode;
1280 int i;
1281
1282 // Figure what the primordial thread stack base is. Code is inspired
1283 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1284 // followed by command name surrounded by parentheses, state, etc.
1285 char stat[2048];
1286 int statlen;
1287
1288 fp = fopen("/proc/self/stat", "r");
1289 if (fp) {
1290 statlen = fread(stat, 1, 2047, fp);
1291 stat[statlen] = '\0';
1292 fclose(fp);
1293
1294 // Skip pid and the command string. Note that we could be dealing with
1295 // weird command names, e.g. user could decide to rename java launcher
1296 // to "java 1.4.2 :)", then the stat file would look like
1297 // 1234 (java 1.4.2 :)) R ... ...
1298 // We don't really need to know the command string, just find the last
1299 // occurrence of ")" and then start parsing from there. See bug 4726580.
1300 char * s = strrchr(stat, ')');
1301
1302 i = 0;
1303 if (s) {
1304 // Skip blank chars
1305 do s++; while (isspace(*s));
1306
1307 #define _UFM UINTX_FORMAT
1308 #define _DFM INTX_FORMAT
1309
1310 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1311 /* 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 */
1312 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,
1313 &state, /* 3 %c */
1314 &ppid, /* 4 %d */
1315 &pgrp, /* 5 %d */
1316 &session, /* 6 %d */
1317 &nr, /* 7 %d */
1318 &tpgrp, /* 8 %d */
1319 &flags, /* 9 %lu */
1320 &minflt, /* 10 %lu */
1321 &cminflt, /* 11 %lu */
1322 &majflt, /* 12 %lu */
1323 &cmajflt, /* 13 %lu */
1324 &utime, /* 14 %lu */
1325 &stime, /* 15 %lu */
1326 &cutime, /* 16 %ld */
1327 &cstime, /* 17 %ld */
1328 &prio, /* 18 %ld */
1329 &nice, /* 19 %ld */
1330 &junk, /* 20 %ld */
1331 &it_real, /* 21 %ld */
1332 &start, /* 22 UINTX_FORMAT */
1333 &vsize, /* 23 UINTX_FORMAT */
1334 &rss, /* 24 INTX_FORMAT */
1335 &rsslim, /* 25 UINTX_FORMAT */
1336 &scodes, /* 26 UINTX_FORMAT */
1337 &ecode, /* 27 UINTX_FORMAT */
1338 &stack_start); /* 28 UINTX_FORMAT */
1339 }
1340
1341 #undef _UFM
1342 #undef _DFM
1343
1344 if (i != 28 - 2) {
1345 assert(false, "Bad conversion from /proc/self/stat");
1346 // product mode - assume we are the initial thread, good luck in the
1347 // embedded case.
1348 warning("Can't detect initial thread stack location - bad conversion");
1349 stack_start = (uintptr_t) &rlim;
1350 }
1351 } else {
1352 // For some reason we can't open /proc/self/stat (for example, running on
1353 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1354 // most cases, so don't abort:
1355 warning("Can't detect initial thread stack location - no /proc/self/stat");
1356 stack_start = (uintptr_t) &rlim;
1357 }
1358 }
1359
1360 // Now we have a pointer (stack_start) very close to the stack top, the
1361 // next thing to do is to figure out the exact location of stack top. We
1362 // can find out the virtual memory area that contains stack_start by
1363 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1364 // and its upper limit is the real stack top. (again, this would fail if
1365 // running inside chroot, because /proc may not exist.)
1366
1367 uintptr_t stack_top;
1368 address low, high;
1369 if (find_vma((address)stack_start, &low, &high)) {
1370 // success, "high" is the true stack top. (ignore "low", because initial
1371 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1372 stack_top = (uintptr_t)high;
1373 } else {
1374 // failed, likely because /proc/self/maps does not exist
1375 warning("Can't detect initial thread stack location - find_vma failed");
1376 // best effort: stack_start is normally within a few pages below the real
1377 // stack top, use it as stack top, and reduce stack size so we won't put
1378 // guard page outside stack.
1379 stack_top = stack_start;
1380 stack_size -= 16 * page_size();
1381 }
1382
1383 // stack_top could be partially down the page so align it
1384 stack_top = align_size_up(stack_top, page_size());
1385
1386 if (max_size && stack_size > max_size) {
1387 _initial_thread_stack_size = max_size;
1388 } else {
1389 _initial_thread_stack_size = stack_size;
1390 }
1391
1392 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1393 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1394 }
1395
1396 ////////////////////////////////////////////////////////////////////////////////
1397 // time support
1398
1399 // Time since start-up in seconds to a fine granularity.
1400 // Used by VMSelfDestructTimer and the MemProfiler.
1401 double os::elapsedTime() {
1402
1403 return (double)(os::elapsed_counter()) * 0.000001;
1404 }
1405
1406 jlong os::elapsed_counter() {
1407 timeval time;
1408 int status = gettimeofday(&time, NULL);
1409 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1410 }
1411
1412 jlong os::elapsed_frequency() {
1413 return (1000 * 1000);
1414 }
1415
1416 bool os::supports_vtime() { return true; }
1417 bool os::enable_vtime() { return false; }
1418 bool os::vtime_enabled() { return false; }
1419
1420 double os::elapsedVTime() {
1421 struct rusage usage;
1422 int retval = getrusage(RUSAGE_THREAD, &usage);
1423 if (retval == 0) {
1424 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);
1425 } else {
1426 // better than nothing, but not much
1427 return elapsedTime();
1428 }
1429 }
1430
1431 jlong os::javaTimeMillis() {
1432 timeval time;
1433 int status = gettimeofday(&time, NULL);
1434 assert(status != -1, "linux error");
1435 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1436 }
1437
1438 #ifndef CLOCK_MONOTONIC
1439 #define CLOCK_MONOTONIC (1)
1440 #endif
1441
1442 void os::Linux::clock_init() {
1443 // we do dlopen's in this particular order due to bug in linux
1444 // dynamical loader (see 6348968) leading to crash on exit
1445 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1446 if (handle == NULL) {
1447 handle = dlopen("librt.so", RTLD_LAZY);
1448 }
1449
1450 if (handle) {
1451 int (*clock_getres_func)(clockid_t, struct timespec*) =
1452 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1453 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1454 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1455 if (clock_getres_func && clock_gettime_func) {
1456 // See if monotonic clock is supported by the kernel. Note that some
1457 // early implementations simply return kernel jiffies (updated every
1458 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1459 // for nano time (though the monotonic property is still nice to have).
1460 // It's fixed in newer kernels, however clock_getres() still returns
1461 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1462 // resolution for now. Hopefully as people move to new kernels, this
1463 // won't be a problem.
1464 struct timespec res;
1465 struct timespec tp;
1466 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1467 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1468 // yes, monotonic clock is supported
1469 _clock_gettime = clock_gettime_func;
1470 return;
1471 } else {
1472 // close librt if there is no monotonic clock
1473 dlclose(handle);
1474 }
1475 }
1476 }
1477 warning("No monotonic clock was available - timed services may " \
1478 "be adversely affected if the time-of-day clock changes");
1479 }
1480
1481 #ifndef SYS_clock_getres
1482
1483 #if defined(IA32) || defined(AMD64) || defined(AARCH64)
1484 #ifdef BUILTIN_SIM
1485 #define SYS_clock_getres 229
1486 #else
1487 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229) AARCH64_ONLY(114)
1488 #endif
1489 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1490 #else
1491 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1492 #define sys_clock_getres(x,y) -1
1493 #endif
1494
1495 #else
1496 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1497 #endif
1498
1499 void os::Linux::fast_thread_clock_init() {
1500 if (!UseLinuxPosixThreadCPUClocks) {
1501 return;
1502 }
1503 clockid_t clockid;
1504 struct timespec tp;
1505 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1506 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1507
1508 // Switch to using fast clocks for thread cpu time if
1509 // the sys_clock_getres() returns 0 error code.
1510 // Note, that some kernels may support the current thread
1511 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1512 // returned by the pthread_getcpuclockid().
1513 // If the fast Posix clocks are supported then the sys_clock_getres()
1514 // must return at least tp.tv_sec == 0 which means a resolution
1515 // better than 1 sec. This is extra check for reliability.
1516
1517 if(pthread_getcpuclockid_func &&
1518 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1519 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1520
1521 _supports_fast_thread_cpu_time = true;
1522 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1523 }
1524 }
1525
1526 jlong os::javaTimeNanos() {
1527 if (Linux::supports_monotonic_clock()) {
1528 struct timespec tp;
1529 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1530 assert(status == 0, "gettime error");
1531 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1532 return result;
1533 } else {
1534 timeval time;
1535 int status = gettimeofday(&time, NULL);
1536 assert(status != -1, "linux error");
1537 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1538 return 1000 * usecs;
1539 }
1540 }
1541
1542 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1543 if (Linux::supports_monotonic_clock()) {
1544 info_ptr->max_value = ALL_64_BITS;
1545
1546 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1547 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1548 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1549 } else {
1550 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1551 info_ptr->max_value = ALL_64_BITS;
1552
1553 // gettimeofday is a real time clock so it skips
1554 info_ptr->may_skip_backward = true;
1555 info_ptr->may_skip_forward = true;
1556 }
1557
1558 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1559 }
1560
1561 // Return the real, user, and system times in seconds from an
1562 // arbitrary fixed point in the past.
1563 bool os::getTimesSecs(double* process_real_time,
1564 double* process_user_time,
1565 double* process_system_time) {
1566 struct tms ticks;
1567 clock_t real_ticks = times(&ticks);
1568
1569 if (real_ticks == (clock_t) (-1)) {
1570 return false;
1571 } else {
1572 double ticks_per_second = (double) clock_tics_per_sec;
1573 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1574 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1575 *process_real_time = ((double) real_ticks) / ticks_per_second;
1576
1577 return true;
1578 }
1579 }
1580
1581
1582 char * os::local_time_string(char *buf, size_t buflen) {
1583 struct tm t;
1584 time_t long_time;
1585 time(&long_time);
1586 localtime_r(&long_time, &t);
1587 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1588 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1589 t.tm_hour, t.tm_min, t.tm_sec);
1590 return buf;
1591 }
1592
1593 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1594 return localtime_r(clock, res);
1595 }
1596
1597 ////////////////////////////////////////////////////////////////////////////////
1598 // runtime exit support
1599
1600 // Note: os::shutdown() might be called very early during initialization, or
1601 // called from signal handler. Before adding something to os::shutdown(), make
1602 // sure it is async-safe and can handle partially initialized VM.
1603 void os::shutdown() {
1604
1605 // allow PerfMemory to attempt cleanup of any persistent resources
1606 perfMemory_exit();
1607
1608 // needs to remove object in file system
1609 AttachListener::abort();
1610
1611 // flush buffered output, finish log files
1612 ostream_abort();
1613
1614 // Check for abort hook
1615 abort_hook_t abort_hook = Arguments::abort_hook();
1616 if (abort_hook != NULL) {
1617 abort_hook();
1618 }
1619
1620 }
1621
1622 // Note: os::abort() might be called very early during initialization, or
1623 // called from signal handler. Before adding something to os::abort(), make
1624 // sure it is async-safe and can handle partially initialized VM.
1625 void os::abort(bool dump_core) {
1626 os::shutdown();
1627 if (dump_core) {
1628 #ifndef PRODUCT
1629 fdStream out(defaultStream::output_fd());
1630 out.print_raw("Current thread is ");
1631 char buf[16];
1632 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1633 out.print_raw_cr(buf);
1634 out.print_raw_cr("Dumping core ...");
1635 #endif
1636 ::abort(); // dump core
1637 }
1638
1639 ::exit(1);
1640 }
1641
1642 // Die immediately, no exit hook, no abort hook, no cleanup.
1643 void os::die() {
1644 // _exit() on LinuxThreads only kills current thread
1645 ::abort();
1646 }
1647
1648
1649 // This method is a copy of JDK's sysGetLastErrorString
1650 // from src/solaris/hpi/src/system_md.c
1651
1652 size_t os::lasterror(char *buf, size_t len) {
1653
1654 if (errno == 0) return 0;
1655
1656 const char *s = ::strerror(errno);
1657 size_t n = ::strlen(s);
1658 if (n >= len) {
1659 n = len - 1;
1660 }
1661 ::strncpy(buf, s, n);
1662 buf[n] = '\0';
1663 return n;
1664 }
1665
1666 intx os::current_thread_id() { return (intx)pthread_self(); }
1667 int os::current_process_id() {
1668
1669 // Under the old linux thread library, linux gives each thread
1670 // its own process id. Because of this each thread will return
1671 // a different pid if this method were to return the result
1672 // of getpid(2). Linux provides no api that returns the pid
1673 // of the launcher thread for the vm. This implementation
1674 // returns a unique pid, the pid of the launcher thread
1675 // that starts the vm 'process'.
1676
1677 // Under the NPTL, getpid() returns the same pid as the
1678 // launcher thread rather than a unique pid per thread.
1679 // Use gettid() if you want the old pre NPTL behaviour.
1680
1681 // if you are looking for the result of a call to getpid() that
1682 // returns a unique pid for the calling thread, then look at the
1683 // OSThread::thread_id() method in osThread_linux.hpp file
1684
1685 return (int)(_initial_pid ? _initial_pid : getpid());
1686 }
1687
1688 // DLL functions
1689
1690 const char* os::dll_file_extension() { return ".so"; }
1691
1692 // This must be hard coded because it's the system's temporary
1693 // directory not the java application's temp directory, ala java.io.tmpdir.
1694 const char* os::get_temp_directory() { return "/tmp"; }
1695
1696 static bool file_exists(const char* filename) {
1697 struct stat statbuf;
1698 if (filename == NULL || strlen(filename) == 0) {
1699 return false;
1700 }
1701 return os::stat(filename, &statbuf) == 0;
1702 }
1703
1704 void os::dll_build_name(char* buffer, size_t buflen,
1705 const char* pname, const char* fname) {
1706 // Copied from libhpi
1707 const size_t pnamelen = pname ? strlen(pname) : 0;
1708
1709 // Quietly truncate on buffer overflow. Should be an error.
1710 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1711 *buffer = '\0';
1712 return;
1713 }
1714
1715 if (pnamelen == 0) {
1716 snprintf(buffer, buflen, "lib%s.so", fname);
1717 } else if (strchr(pname, *os::path_separator()) != NULL) {
1718 int n;
1719 char** pelements = split_path(pname, &n);
1720 for (int i = 0 ; i < n ; i++) {
1721 // Really shouldn't be NULL, but check can't hurt
1722 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1723 continue; // skip the empty path values
1724 }
1725 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1726 if (file_exists(buffer)) {
1727 break;
1728 }
1729 }
1730 // release the storage
1731 for (int i = 0 ; i < n ; i++) {
1732 if (pelements[i] != NULL) {
1733 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1734 }
1735 }
1736 if (pelements != NULL) {
1737 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1738 }
1739 } else {
1740 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1741 }
1742 }
1743
1744 const char* os::get_current_directory(char *buf, int buflen) {
1745 return getcwd(buf, buflen);
1746 }
1747
1748 // check if addr is inside libjvm[_g].so
1749 bool os::address_is_in_vm(address addr) {
1750 static address libjvm_base_addr;
1751 Dl_info dlinfo;
1752
1753 if (libjvm_base_addr == NULL) {
1754 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1755 libjvm_base_addr = (address)dlinfo.dli_fbase;
1756 }
1757 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1758 }
1759
1760 if (dladdr((void *)addr, &dlinfo) != 0) {
1761 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1762 }
1763
1764 return false;
1765 }
1766
1767 bool os::dll_address_to_function_name(address addr, char *buf,
1768 int buflen, int *offset) {
1769 // buf is not optional, but offset is optional
1770 assert(buf != NULL, "sanity check");
1771
1772 Dl_info dlinfo;
1773
1774 if (dladdr((void*)addr, &dlinfo) != 0) {
1775 // see if we have a matching symbol
1776 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1777 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1778 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1779 }
1780 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1781 return true;
1782 }
1783 // no matching symbol so try for just file info
1784 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1785 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1786 buf, buflen, offset, dlinfo.dli_fname)) {
1787 return true;
1788 }
1789 }
1790 }
1791
1792 buf[0] = '\0';
1793 if (offset != NULL) *offset = -1;
1794 return false;
1795 }
1796
1797 struct _address_to_library_name {
1798 address addr; // input : memory address
1799 size_t buflen; // size of fname
1800 char* fname; // output: library name
1801 address base; // library base addr
1802 };
1803
1804 static int address_to_library_name_callback(struct dl_phdr_info *info,
1805 size_t size, void *data) {
1806 int i;
1807 bool found = false;
1808 address libbase = NULL;
1809 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1810
1811 // iterate through all loadable segments
1812 for (i = 0; i < info->dlpi_phnum; i++) {
1813 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1814 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1815 // base address of a library is the lowest address of its loaded
1816 // segments.
1817 if (libbase == NULL || libbase > segbase) {
1818 libbase = segbase;
1819 }
1820 // see if 'addr' is within current segment
1821 if (segbase <= d->addr &&
1822 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1823 found = true;
1824 }
1825 }
1826 }
1827
1828 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1829 // so dll_address_to_library_name() can fall through to use dladdr() which
1830 // can figure out executable name from argv[0].
1831 if (found && info->dlpi_name && info->dlpi_name[0]) {
1832 d->base = libbase;
1833 if (d->fname) {
1834 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1835 }
1836 return 1;
1837 }
1838 return 0;
1839 }
1840
1841 bool os::dll_address_to_library_name(address addr, char* buf,
1842 int buflen, int* offset) {
1843 // buf is not optional, but offset is optional
1844 assert(buf != NULL, "sanity check");
1845
1846 Dl_info dlinfo;
1847 struct _address_to_library_name data;
1848
1849 // There is a bug in old glibc dladdr() implementation that it could resolve
1850 // to wrong library name if the .so file has a base address != NULL. Here
1851 // we iterate through the program headers of all loaded libraries to find
1852 // out which library 'addr' really belongs to. This workaround can be
1853 // removed once the minimum requirement for glibc is moved to 2.3.x.
1854 data.addr = addr;
1855 data.fname = buf;
1856 data.buflen = buflen;
1857 data.base = NULL;
1858 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1859
1860 if (rslt) {
1861 // buf already contains library name
1862 if (offset) *offset = addr - data.base;
1863 return true;
1864 }
1865 if (dladdr((void*)addr, &dlinfo) != 0) {
1866 if (dlinfo.dli_fname != NULL) {
1867 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1868 }
1869 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1870 *offset = addr - (address)dlinfo.dli_fbase;
1871 }
1872 return true;
1873 }
1874
1875 buf[0] = '\0';
1876 if (offset) *offset = -1;
1877 return false;
1878 }
1879
1880 // Loads .dll/.so and
1881 // in case of error it checks if .dll/.so was built for the
1882 // same architecture as Hotspot is running on
1883
1884
1885 // Remember the stack's state. The Linux dynamic linker will change
1886 // the stack to 'executable' at most once, so we must safepoint only once.
1887 bool os::Linux::_stack_is_executable = false;
1888
1889 // VM operation that loads a library. This is necessary if stack protection
1890 // of the Java stacks can be lost during loading the library. If we
1891 // do not stop the Java threads, they can stack overflow before the stacks
1892 // are protected again.
1893 class VM_LinuxDllLoad: public VM_Operation {
1894 private:
1895 const char *_filename;
1896 char *_ebuf;
1897 int _ebuflen;
1898 void *_lib;
1899 public:
1900 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1901 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1902 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1903 void doit() {
1904 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1905 os::Linux::_stack_is_executable = true;
1906 }
1907 void* loaded_library() { return _lib; }
1908 };
1909
1910 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1911 {
1912 void * result = NULL;
1913 bool load_attempted = false;
1914
1915 // Check whether the library to load might change execution rights
1916 // of the stack. If they are changed, the protection of the stack
1917 // guard pages will be lost. We need a safepoint to fix this.
1918 //
1919 // See Linux man page execstack(8) for more info.
1920 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1921 ElfFile ef(filename);
1922 if (!ef.specifies_noexecstack()) {
1923 if (!is_init_completed()) {
1924 os::Linux::_stack_is_executable = true;
1925 // This is OK - No Java threads have been created yet, and hence no
1926 // stack guard pages to fix.
1927 //
1928 // This should happen only when you are building JDK7 using a very
1929 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1930 //
1931 // Dynamic loader will make all stacks executable after
1932 // this function returns, and will not do that again.
1933 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1934 } else {
1935 warning("You have loaded library %s which might have disabled stack guard. "
1936 "The VM will try to fix the stack guard now.\n"
1937 "It's highly recommended that you fix the library with "
1938 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1939 filename);
1940
1941 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1942 JavaThread *jt = JavaThread::current();
1943 if (jt->thread_state() != _thread_in_native) {
1944 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1945 // that requires ExecStack. Cannot enter safe point. Let's give up.
1946 warning("Unable to fix stack guard. Giving up.");
1947 } else {
1948 if (!LoadExecStackDllInVMThread) {
1949 // This is for the case where the DLL has an static
1950 // constructor function that executes JNI code. We cannot
1951 // load such DLLs in the VMThread.
1952 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1953 }
1954
1955 ThreadInVMfromNative tiv(jt);
1956 debug_only(VMNativeEntryWrapper vew;)
1957
1958 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1959 VMThread::execute(&op);
1960 if (LoadExecStackDllInVMThread) {
1961 result = op.loaded_library();
1962 }
1963 load_attempted = true;
1964 }
1965 }
1966 }
1967 }
1968
1969 if (!load_attempted) {
1970 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1971 }
1972
1973 if (result != NULL) {
1974 // Successful loading
1975 return result;
1976 }
1977
1978 Elf32_Ehdr elf_head;
1979 int diag_msg_max_length=ebuflen-strlen(ebuf);
1980 char* diag_msg_buf=ebuf+strlen(ebuf);
1981
1982 if (diag_msg_max_length==0) {
1983 // No more space in ebuf for additional diagnostics message
1984 return NULL;
1985 }
1986
1987
1988 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1989
1990 if (file_descriptor < 0) {
1991 // Can't open library, report dlerror() message
1992 return NULL;
1993 }
1994
1995 bool failed_to_read_elf_head=
1996 (sizeof(elf_head)!=
1997 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1998
1999 ::close(file_descriptor);
2000 if (failed_to_read_elf_head) {
2001 // file i/o error - report dlerror() msg
2002 return NULL;
2003 }
2004
2005 typedef struct {
2006 Elf32_Half code; // Actual value as defined in elf.h
2007 Elf32_Half compat_class; // Compatibility of archs at VM's sense
2008 char elf_class; // 32 or 64 bit
2009 char endianess; // MSB or LSB
2010 char* name; // String representation
2011 } arch_t;
2012
2013 #ifndef EM_486
2014 #define EM_486 6 /* Intel 80486 */
2015 #endif
2016
2017 #ifndef EM_AARCH64
2018 #define EM_AARCH64 183
2019 #endif
2020
2021 static const arch_t arch_array[]={
2022 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
2023 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
2024 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
2025 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
2026 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
2027 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
2028 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
2029 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
2030 #if defined(VM_LITTLE_ENDIAN)
2031 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
2032 #else
2033 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
2034 #endif
2035 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
2036 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
2037 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
2038 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
2039 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
2040 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
2041 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
2042 {EM_SH, EM_SH, ELFCLASS32, ELFDATA2LSB, (char*)"SH"}, /* Support little endian only*/
2043 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"} /* Support little endian only*/
2044 };
2045
2046 #if (defined IA32)
2047 static Elf32_Half running_arch_code=EM_386;
2048 #elif (defined AMD64)
2049 static Elf32_Half running_arch_code=EM_X86_64;
2050 #elif (defined IA64)
2051 static Elf32_Half running_arch_code=EM_IA_64;
2052 #elif (defined __sparc) && (defined _LP64)
2053 static Elf32_Half running_arch_code=EM_SPARCV9;
2054 #elif (defined __sparc) && (!defined _LP64)
2055 static Elf32_Half running_arch_code=EM_SPARC;
2056 #elif (defined __powerpc64__)
2057 static Elf32_Half running_arch_code=EM_PPC64;
2058 #elif (defined __powerpc__)
2059 static Elf32_Half running_arch_code=EM_PPC;
2060 #elif (defined ARM)
2061 static Elf32_Half running_arch_code=EM_ARM;
2062 #elif (defined S390)
2063 static Elf32_Half running_arch_code=EM_S390;
2064 #elif (defined ALPHA)
2065 static Elf32_Half running_arch_code=EM_ALPHA;
2066 #elif (defined MIPSEL)
2067 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
2068 #elif (defined PARISC)
2069 static Elf32_Half running_arch_code=EM_PARISC;
2070 #elif (defined MIPS)
2071 static Elf32_Half running_arch_code=EM_MIPS;
2072 #elif (defined M68K)
2073 static Elf32_Half running_arch_code=EM_68K;
2074 #elif (defined SH)
2075 static Elf32_Half running_arch_code=EM_SH;
2076 #elif (defined AARCH64)
2077 static Elf32_Half running_arch_code=EM_AARCH64;
2078 #else
2079 #error Method os::dll_load requires that one of following is defined:\
2080 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, SH, AARCH64
2081 #endif
2082
2083 // Identify compatability class for VM's architecture and library's architecture
2084 // Obtain string descriptions for architectures
2085
2086 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2087 int running_arch_index=-1;
2088
2089 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2090 if (running_arch_code == arch_array[i].code) {
2091 running_arch_index = i;
2092 }
2093 if (lib_arch.code == arch_array[i].code) {
2094 lib_arch.compat_class = arch_array[i].compat_class;
2095 lib_arch.name = arch_array[i].name;
2096 }
2097 }
2098
2099 assert(running_arch_index != -1,
2100 "Didn't find running architecture code (running_arch_code) in arch_array");
2101 if (running_arch_index == -1) {
2102 // Even though running architecture detection failed
2103 // we may still continue with reporting dlerror() message
2104 return NULL;
2105 }
2106
2107 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2108 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2109 return NULL;
2110 }
2111
2112 #ifndef S390
2113 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2114 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2115 return NULL;
2116 }
2117 #endif // !S390
2118
2119 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2120 if ( lib_arch.name!=NULL ) {
2121 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2122 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2123 lib_arch.name, arch_array[running_arch_index].name);
2124 } else {
2125 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2126 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2127 lib_arch.code,
2128 arch_array[running_arch_index].name);
2129 }
2130 }
2131
2132 return NULL;
2133 }
2134
2135 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2136 void * result = ::dlopen(filename, RTLD_LAZY);
2137 if (result == NULL) {
2138 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2139 ebuf[ebuflen-1] = '\0';
2140 }
2141 return result;
2142 }
2143
2144 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2145 void * result = NULL;
2146 if (LoadExecStackDllInVMThread) {
2147 result = dlopen_helper(filename, ebuf, ebuflen);
2148 }
2149
2150 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2151 // library that requires an executable stack, or which does not have this
2152 // stack attribute set, dlopen changes the stack attribute to executable. The
2153 // read protection of the guard pages gets lost.
2154 //
2155 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2156 // may have been queued at the same time.
2157
2158 if (!_stack_is_executable) {
2159 JavaThread *jt = Threads::first();
2160
2161 while (jt) {
2162 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2163 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2164 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2165 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2166 warning("Attempt to reguard stack yellow zone failed.");
2167 }
2168 }
2169 jt = jt->next();
2170 }
2171 }
2172
2173 return result;
2174 }
2175
2176 /*
2177 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2178 * chances are you might want to run the generated bits against glibc-2.0
2179 * libdl.so, so always use locking for any version of glibc.
2180 */
2181 void* os::dll_lookup(void* handle, const char* name) {
2182 pthread_mutex_lock(&dl_mutex);
2183 void* res = dlsym(handle, name);
2184 pthread_mutex_unlock(&dl_mutex);
2185 return res;
2186 }
2187
2188
2189 static bool _print_ascii_file(const char* filename, outputStream* st) {
2190 int fd = ::open(filename, O_RDONLY);
2191 if (fd == -1) {
2192 return false;
2193 }
2194
2195 char buf[32];
2196 int bytes;
2197 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2198 st->print_raw(buf, bytes);
2199 }
2200
2201 ::close(fd);
2202
2203 return true;
2204 }
2205
2206 bool _print_lsb_file(const char* filename, outputStream* st) {
2207 int fd = open(filename, O_RDONLY);
2208 if (fd == -1) {
2209 return false;
2210 }
2211
2212 char buf[512], *d_i, *d_r, *d_c;
2213 int bytes;
2214
2215 if ((bytes = read(fd, buf, sizeof(buf)-1)) == sizeof(buf)-1) {
2216 close(fd);
2217 return false;
2218 }
2219 close(fd);
2220
2221 buf[bytes] = '\n';
2222 buf[bytes+1] = '\0';
2223 d_i = strstr(buf, "DISTRIB_ID=");
2224 d_r = strstr(buf, "DISTRIB_RELEASE=");
2225 d_c = strstr(buf, "DISTRIB_CODENAME=");
2226 if (!d_i || !d_r || !d_c) {
2227 return false;
2228 }
2229 d_i = strchr(d_i, '=') + 1; *strchrnul(d_i, '\n') = '\0';
2230 d_r = strchr(d_r, '=') + 1; *strchrnul(d_r, '\n') = '\0';
2231 d_c = strchr(d_c, '=') + 1; *strchrnul(d_c, '\n') = '\0';
2232 st->print("%s %s (%s)", d_i, d_r, d_c);
2233
2234 return true;
2235 }
2236
2237 void os::print_dll_info(outputStream *st) {
2238 st->print_cr("Dynamic libraries:");
2239
2240 char fname[32];
2241 pid_t pid = os::Linux::gettid();
2242
2243 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2244
2245 if (!_print_ascii_file(fname, st)) {
2246 st->print("Can not get library information for pid = %d\n", pid);
2247 }
2248 }
2249
2250 void os::print_os_info_brief(outputStream* st) {
2251 os::Linux::print_distro_info(st);
2252
2253 os::Posix::print_uname_info(st);
2254
2255 os::Linux::print_libversion_info(st);
2256
2257 }
2258
2259 void os::print_os_info(outputStream* st) {
2260 st->print("OS:");
2261
2262 os::Linux::print_distro_info(st);
2263
2264 os::Posix::print_uname_info(st);
2265
2266 // Print warning if unsafe chroot environment detected
2267 if (unsafe_chroot_detected) {
2268 st->print("WARNING!! ");
2269 st->print_cr(unstable_chroot_error);
2270 }
2271
2272 os::Linux::print_libversion_info(st);
2273
2274 os::Posix::print_rlimit_info(st);
2275
2276 os::Posix::print_load_average(st);
2277
2278 os::Linux::print_full_memory_info(st);
2279 }
2280
2281 // Try to identify popular distros.
2282 // Most Linux distributions have /etc/XXX-release file, which contains
2283 // the OS version string. Some have more than one /etc/XXX-release file
2284 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2285 // so the order is important.
2286 void os::Linux::print_distro_info(outputStream* st) {
2287 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2288 !_print_ascii_file("/etc/sun-release", st) &&
2289 !_print_ascii_file("/etc/redhat-release", st) &&
2290 !_print_ascii_file("/etc/SuSE-release", st) &&
2291 !_print_ascii_file("/etc/turbolinux-release", st) &&
2292 !_print_ascii_file("/etc/gentoo-release", st) &&
2293 !_print_lsb_file("/etc/lsb-release", st) &&
2294 !_print_ascii_file("/etc/debian_version", st) &&
2295 !_print_ascii_file("/etc/ltib-release", st) &&
2296 !_print_ascii_file("/etc/angstrom-version", st)) {
2297 st->print("Linux");
2298 }
2299 st->cr();
2300 }
2301
2302 void os::Linux::print_libversion_info(outputStream* st) {
2303 // libc, pthread
2304 st->print("libc:");
2305 st->print(os::Linux::glibc_version()); st->print(" ");
2306 st->print(os::Linux::libpthread_version()); st->print(" ");
2307 if (os::Linux::is_LinuxThreads()) {
2308 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2309 }
2310 st->cr();
2311 }
2312
2313 void os::Linux::print_full_memory_info(outputStream* st) {
2314 st->print("\n/proc/meminfo:\n");
2315 _print_ascii_file("/proc/meminfo", st);
2316 st->cr();
2317 }
2318
2319 void os::print_memory_info(outputStream* st) {
2320
2321 st->print("Memory:");
2322 st->print(" %dk page", os::vm_page_size()>>10);
2323
2324 // values in struct sysinfo are "unsigned long"
2325 struct sysinfo si;
2326 sysinfo(&si);
2327
2328 st->print(", physical " UINT64_FORMAT "k",
2329 os::physical_memory() >> 10);
2330 st->print("(" UINT64_FORMAT "k free)",
2331 os::available_memory() >> 10);
2332 st->print(", swap " UINT64_FORMAT "k",
2333 ((jlong)si.totalswap * si.mem_unit) >> 10);
2334 st->print("(" UINT64_FORMAT "k free)",
2335 ((jlong)si.freeswap * si.mem_unit) >> 10);
2336 st->cr();
2337 }
2338
2339 void os::pd_print_cpu_info(outputStream* st) {
2340 st->print("\n/proc/cpuinfo:\n");
2341 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2342 st->print(" <Not Available>");
2343 }
2344 st->cr();
2345 }
2346
2347 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2348 // but they're the same for all the linux arch that we support
2349 // and they're the same for solaris but there's no common place to put this.
2350 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2351 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2352 "ILL_COPROC", "ILL_BADSTK" };
2353
2354 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2355 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2356 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2357
2358 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2359
2360 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2361
2362 void os::print_siginfo(outputStream* st, void* siginfo) {
2363 st->print("siginfo:");
2364
2365 const int buflen = 100;
2366 char buf[buflen];
2367 siginfo_t *si = (siginfo_t*)siginfo;
2368 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2369 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2370 st->print("si_errno=%s", buf);
2371 } else {
2372 st->print("si_errno=%d", si->si_errno);
2373 }
2374 const int c = si->si_code;
2375 assert(c > 0, "unexpected si_code");
2376 switch (si->si_signo) {
2377 case SIGILL:
2378 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2379 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2380 break;
2381 case SIGFPE:
2382 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2383 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2384 break;
2385 case SIGSEGV:
2386 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2387 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2388 break;
2389 case SIGBUS:
2390 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2391 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2392 break;
2393 default:
2394 st->print(", si_code=%d", si->si_code);
2395 // no si_addr
2396 }
2397
2398 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2399 UseSharedSpaces) {
2400 FileMapInfo* mapinfo = FileMapInfo::current_info();
2401 if (mapinfo->is_in_shared_space(si->si_addr)) {
2402 st->print("\n\nError accessing class data sharing archive." \
2403 " Mapped file inaccessible during execution, " \
2404 " possible disk/network problem.");
2405 }
2406 }
2407 st->cr();
2408 }
2409
2410
2411 static void print_signal_handler(outputStream* st, int sig,
2412 char* buf, size_t buflen);
2413
2414 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2415 st->print_cr("Signal Handlers:");
2416 print_signal_handler(st, SIGSEGV, buf, buflen);
2417 print_signal_handler(st, SIGBUS , buf, buflen);
2418 print_signal_handler(st, SIGFPE , buf, buflen);
2419 print_signal_handler(st, SIGPIPE, buf, buflen);
2420 print_signal_handler(st, SIGXFSZ, buf, buflen);
2421 print_signal_handler(st, SIGILL , buf, buflen);
2422 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2423 print_signal_handler(st, SR_signum, buf, buflen);
2424 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2425 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2426 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2427 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2428 print_signal_handler(st, SIGTRAP, buf, buflen);
2429 }
2430
2431 static char saved_jvm_path[MAXPATHLEN] = {0};
2432
2433 // Find the full path to the current module, libjvm.so or libjvm_g.so
2434 void os::jvm_path(char *buf, jint buflen) {
2435 // Error checking.
2436 if (buflen < MAXPATHLEN) {
2437 assert(false, "must use a large-enough buffer");
2438 buf[0] = '\0';
2439 return;
2440 }
2441 // Lazy resolve the path to current module.
2442 if (saved_jvm_path[0] != 0) {
2443 strcpy(buf, saved_jvm_path);
2444 return;
2445 }
2446
2447 char dli_fname[MAXPATHLEN];
2448 bool ret = dll_address_to_library_name(
2449 CAST_FROM_FN_PTR(address, os::jvm_path),
2450 dli_fname, sizeof(dli_fname), NULL);
2451 assert(ret, "cannot locate libjvm");
2452 char *rp = NULL;
2453 if (ret && dli_fname[0] != '\0') {
2454 rp = realpath(dli_fname, buf);
2455 }
2456 if (rp == NULL)
2457 return;
2458
2459 if (Arguments::created_by_gamma_launcher()) {
2460 // Support for the gamma launcher. Typical value for buf is
2461 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2462 // the right place in the string, then assume we are installed in a JDK and
2463 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2464 // up the path so it looks like libjvm.so is installed there (append a
2465 // fake suffix hotspot/libjvm.so).
2466 const char *p = buf + strlen(buf) - 1;
2467 for (int count = 0; p > buf && count < 5; ++count) {
2468 for (--p; p > buf && *p != '/'; --p)
2469 /* empty */ ;
2470 }
2471
2472 if (strncmp(p, "/jre/lib/", 9) != 0) {
2473 // Look for JAVA_HOME in the environment.
2474 char* java_home_var = ::getenv("JAVA_HOME");
2475 if (java_home_var != NULL && java_home_var[0] != 0) {
2476 char* jrelib_p;
2477 int len;
2478
2479 // Check the current module name "libjvm.so" or "libjvm_g.so".
2480 p = strrchr(buf, '/');
2481 assert(strstr(p, "/libjvm") == p, "invalid library name");
2482 p = strstr(p, "_g") ? "_g" : "";
2483
2484 rp = realpath(java_home_var, buf);
2485 if (rp == NULL)
2486 return;
2487
2488 // determine if this is a legacy image or modules image
2489 // modules image doesn't have "jre" subdirectory
2490 len = strlen(buf);
2491 assert(len < buflen, "Ran out of buffer room");
2492 jrelib_p = buf + len;
2493 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2494 if (0 != access(buf, F_OK)) {
2495 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2496 }
2497
2498 if (0 == access(buf, F_OK)) {
2499 // Use current module name "libjvm[_g].so" instead of
2500 // "libjvm"debug_only("_g")".so" since for fastdebug version
2501 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2502 len = strlen(buf);
2503 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2504 } else {
2505 // Go back to path of .so
2506 rp = realpath(dli_fname, buf);
2507 if (rp == NULL)
2508 return;
2509 }
2510 }
2511 }
2512 }
2513
2514 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2515 }
2516
2517 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2518 // no prefix required, not even "_"
2519 }
2520
2521 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2522 // no suffix required
2523 }
2524
2525 ////////////////////////////////////////////////////////////////////////////////
2526 // sun.misc.Signal support
2527
2528 static volatile jint sigint_count = 0;
2529
2530 static void
2531 UserHandler(int sig, void *siginfo, void *context) {
2532 // 4511530 - sem_post is serialized and handled by the manager thread. When
2533 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2534 // don't want to flood the manager thread with sem_post requests.
2535 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2536 return;
2537
2538 // Ctrl-C is pressed during error reporting, likely because the error
2539 // handler fails to abort. Let VM die immediately.
2540 if (sig == SIGINT && is_error_reported()) {
2541 os::die();
2542 }
2543
2544 os::signal_notify(sig);
2545 }
2546
2547 void* os::user_handler() {
2548 return CAST_FROM_FN_PTR(void*, UserHandler);
2549 }
2550
2551 class Semaphore : public StackObj {
2552 public:
2553 Semaphore();
2554 ~Semaphore();
2555 void signal();
2556 void wait();
2557 bool trywait();
2558 bool timedwait(unsigned int sec, int nsec);
2559 private:
2560 sem_t _semaphore;
2561 };
2562
2563 Semaphore::Semaphore() {
2564 sem_init(&_semaphore, 0, 0);
2565 }
2566
2567 Semaphore::~Semaphore() {
2568 sem_destroy(&_semaphore);
2569 }
2570
2571 void Semaphore::signal() {
2572 sem_post(&_semaphore);
2573 }
2574
2575 void Semaphore::wait() {
2576 sem_wait(&_semaphore);
2577 }
2578
2579 bool Semaphore::trywait() {
2580 return sem_trywait(&_semaphore) == 0;
2581 }
2582
2583 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2584
2585 struct timespec ts;
2586 // Semaphore's are always associated with CLOCK_REALTIME
2587 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2588 // see unpackTime for discussion on overflow checking
2589 if (sec >= MAX_SECS) {
2590 ts.tv_sec += MAX_SECS;
2591 ts.tv_nsec = 0;
2592 } else {
2593 ts.tv_sec += sec;
2594 ts.tv_nsec += nsec;
2595 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2596 ts.tv_nsec -= NANOSECS_PER_SEC;
2597 ++ts.tv_sec; // note: this must be <= max_secs
2598 }
2599 }
2600
2601 while (1) {
2602 int result = sem_timedwait(&_semaphore, &ts);
2603 if (result == 0) {
2604 return true;
2605 } else if (errno == EINTR) {
2606 continue;
2607 } else if (errno == ETIMEDOUT) {
2608 return false;
2609 } else {
2610 return false;
2611 }
2612 }
2613 }
2614
2615 extern "C" {
2616 typedef void (*sa_handler_t)(int);
2617 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2618 }
2619
2620 void* os::signal(int signal_number, void* handler) {
2621 struct sigaction sigAct, oldSigAct;
2622
2623 sigfillset(&(sigAct.sa_mask));
2624 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2625 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2626
2627 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2628 // -1 means registration failed
2629 return (void *)-1;
2630 }
2631
2632 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2633 }
2634
2635 void os::signal_raise(int signal_number) {
2636 ::raise(signal_number);
2637 }
2638
2639 /*
2640 * The following code is moved from os.cpp for making this
2641 * code platform specific, which it is by its very nature.
2642 */
2643
2644 // Will be modified when max signal is changed to be dynamic
2645 int os::sigexitnum_pd() {
2646 return NSIG;
2647 }
2648
2649 // a counter for each possible signal value
2650 static volatile jint pending_signals[NSIG+1] = { 0 };
2651
2652 // Linux(POSIX) specific hand shaking semaphore.
2653 static sem_t sig_sem;
2654 static Semaphore sr_semaphore;
2655
2656 void os::signal_init_pd() {
2657 // Initialize signal structures
2658 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2659
2660 // Initialize signal semaphore
2661 ::sem_init(&sig_sem, 0, 0);
2662 }
2663
2664 void os::signal_notify(int sig) {
2665 Atomic::inc(&pending_signals[sig]);
2666 ::sem_post(&sig_sem);
2667 }
2668
2669 static int check_pending_signals(bool wait) {
2670 Atomic::store(0, &sigint_count);
2671 for (;;) {
2672 for (int i = 0; i < NSIG + 1; i++) {
2673 jint n = pending_signals[i];
2674 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2675 return i;
2676 }
2677 }
2678 if (!wait) {
2679 return -1;
2680 }
2681 JavaThread *thread = JavaThread::current();
2682 ThreadBlockInVM tbivm(thread);
2683
2684 bool threadIsSuspended;
2685 do {
2686 thread->set_suspend_equivalent();
2687 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2688 ::sem_wait(&sig_sem);
2689
2690 // were we externally suspended while we were waiting?
2691 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2692 if (threadIsSuspended) {
2693 //
2694 // The semaphore has been incremented, but while we were waiting
2695 // another thread suspended us. We don't want to continue running
2696 // while suspended because that would surprise the thread that
2697 // suspended us.
2698 //
2699 ::sem_post(&sig_sem);
2700
2701 thread->java_suspend_self();
2702 }
2703 } while (threadIsSuspended);
2704 }
2705 }
2706
2707 int os::signal_lookup() {
2708 return check_pending_signals(false);
2709 }
2710
2711 int os::signal_wait() {
2712 return check_pending_signals(true);
2713 }
2714
2715 ////////////////////////////////////////////////////////////////////////////////
2716 // Virtual Memory
2717
2718 int os::vm_page_size() {
2719 // Seems redundant as all get out
2720 assert(os::Linux::page_size() != -1, "must call os::init");
2721 return os::Linux::page_size();
2722 }
2723
2724 // Solaris allocates memory by pages.
2725 int os::vm_allocation_granularity() {
2726 assert(os::Linux::page_size() != -1, "must call os::init");
2727 return os::Linux::page_size();
2728 }
2729
2730 // Rationale behind this function:
2731 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2732 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2733 // samples for JITted code. Here we create private executable mapping over the code cache
2734 // and then we can use standard (well, almost, as mapping can change) way to provide
2735 // info for the reporting script by storing timestamp and location of symbol
2736 void linux_wrap_code(char* base, size_t size) {
2737 static volatile jint cnt = 0;
2738
2739 if (!UseOprofile) {
2740 return;
2741 }
2742
2743 char buf[PATH_MAX+1];
2744 int num = Atomic::add(1, &cnt);
2745
2746 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2747 os::get_temp_directory(), os::current_process_id(), num);
2748 unlink(buf);
2749
2750 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2751
2752 if (fd != -1) {
2753 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2754 if (rv != (off_t)-1) {
2755 if (::write(fd, "", 1) == 1) {
2756 mmap(base, size,
2757 PROT_READ|PROT_WRITE|PROT_EXEC,
2758 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2759 }
2760 }
2761 ::close(fd);
2762 unlink(buf);
2763 }
2764 }
2765
2766 static bool recoverable_mmap_error(int err) {
2767 // See if the error is one we can let the caller handle. This
2768 // list of errno values comes from JBS-6843484. I can't find a
2769 // Linux man page that documents this specific set of errno
2770 // values so while this list currently matches Solaris, it may
2771 // change as we gain experience with this failure mode.
2772 switch (err) {
2773 case EBADF:
2774 case EINVAL:
2775 case ENOTSUP:
2776 // let the caller deal with these errors
2777 return true;
2778
2779 default:
2780 // Any remaining errors on this OS can cause our reserved mapping
2781 // to be lost. That can cause confusion where different data
2782 // structures think they have the same memory mapped. The worst
2783 // scenario is if both the VM and a library think they have the
2784 // same memory mapped.
2785 return false;
2786 }
2787 }
2788
2789 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2790 int err) {
2791 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2792 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2793 strerror(err), err);
2794 }
2795
2796 static void warn_fail_commit_memory(char* addr, size_t size,
2797 size_t alignment_hint, bool exec,
2798 int err) {
2799 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2800 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2801 alignment_hint, exec, strerror(err), err);
2802 }
2803
2804 // NOTE: Linux kernel does not really reserve the pages for us.
2805 // All it does is to check if there are enough free pages
2806 // left at the time of mmap(). This could be a potential
2807 // problem.
2808 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2809 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2810 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2811 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2812 if (res != (uintptr_t) MAP_FAILED) {
2813 if (UseNUMAInterleaving) {
2814 numa_make_global(addr, size);
2815 }
2816 return 0;
2817 }
2818
2819 int err = errno; // save errno from mmap() call above
2820
2821 if (!recoverable_mmap_error(err)) {
2822 warn_fail_commit_memory(addr, size, exec, err);
2823 vm_exit_out_of_memory(size, "committing reserved memory.");
2824 }
2825
2826 return err;
2827 }
2828
2829 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2830 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2831 }
2832
2833 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2834 const char* mesg) {
2835 assert(mesg != NULL, "mesg must be specified");
2836 int err = os::Linux::commit_memory_impl(addr, size, exec);
2837 if (err != 0) {
2838 // the caller wants all commit errors to exit with the specified mesg:
2839 warn_fail_commit_memory(addr, size, exec, err);
2840 vm_exit_out_of_memory(size, mesg);
2841 }
2842 }
2843
2844 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2845 #ifndef MAP_HUGETLB
2846 #define MAP_HUGETLB 0x40000
2847 #endif
2848
2849 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2850 #ifndef MADV_HUGEPAGE
2851 #define MADV_HUGEPAGE 14
2852 #endif
2853
2854 int os::Linux::commit_memory_impl(char* addr, size_t size,
2855 size_t alignment_hint, bool exec) {
2856 int err = os::Linux::commit_memory_impl(addr, size, exec);
2857 if (err == 0) {
2858 realign_memory(addr, size, alignment_hint);
2859 }
2860 return err;
2861 }
2862
2863 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2864 bool exec) {
2865 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2866 }
2867
2868 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2869 size_t alignment_hint, bool exec,
2870 const char* mesg) {
2871 assert(mesg != NULL, "mesg must be specified");
2872 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2873 if (err != 0) {
2874 // the caller wants all commit errors to exit with the specified mesg:
2875 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2876 vm_exit_out_of_memory(size, mesg);
2877 }
2878 }
2879
2880 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2881 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2882 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2883 // be supported or the memory may already be backed by huge pages.
2884 ::madvise(addr, bytes, MADV_HUGEPAGE);
2885 }
2886 }
2887
2888 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2889 // This method works by doing an mmap over an existing mmaping and effectively discarding
2890 // the existing pages. However it won't work for SHM-based large pages that cannot be
2891 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2892 // small pages on top of the SHM segment. This method always works for small pages, so we
2893 // allow that in any case.
2894 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2895 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2896 }
2897 }
2898
2899 void os::numa_make_global(char *addr, size_t bytes) {
2900 Linux::numa_interleave_memory(addr, bytes);
2901 }
2902
2903 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2904 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2905 }
2906
2907 bool os::numa_topology_changed() { return false; }
2908
2909 size_t os::numa_get_groups_num() {
2910 int max_node = Linux::numa_max_node();
2911 return max_node > 0 ? max_node + 1 : 1;
2912 }
2913
2914 int os::numa_get_group_id() {
2915 int cpu_id = Linux::sched_getcpu();
2916 if (cpu_id != -1) {
2917 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2918 if (lgrp_id != -1) {
2919 return lgrp_id;
2920 }
2921 }
2922 return 0;
2923 }
2924
2925 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2926 for (size_t i = 0; i < size; i++) {
2927 ids[i] = i;
2928 }
2929 return size;
2930 }
2931
2932 bool os::get_page_info(char *start, page_info* info) {
2933 return false;
2934 }
2935
2936 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2937 return end;
2938 }
2939
2940
2941 int os::Linux::sched_getcpu_syscall(void) {
2942 unsigned int cpu;
2943 int retval = -1;
2944
2945 #if defined(AMD64) || defined(BUILTIN_SIM)
2946 // Unfortunately we have to bring all these macros here from vsyscall.h
2947 // to be able to compile on old linuxes.
2948 # define __NR_vgetcpu 2
2949 # define VSYSCALL_START (-10UL << 20)
2950 # define VSYSCALL_SIZE 1024
2951 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2952 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2953 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2954 retval = vgetcpu(&cpu, NULL, NULL);
2955 #elif defined(IA32) || defined(AARCH64)
2956 # ifndef SYS_getcpu
2957 # define SYS_getcpu AARCH64_ONLY(168) NOT_AARCH64(318)
2958 # endif
2959 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2960 #endif
2961
2962 return (retval == -1) ? retval : cpu;
2963 }
2964
2965 // Something to do with the numa-aware allocator needs these symbols
2966 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2967 extern "C" JNIEXPORT void numa_error(char *where) { }
2968 extern "C" JNIEXPORT int fork1() { return fork(); }
2969
2970
2971 // If we are running with libnuma version > 2, then we should
2972 // be trying to use symbols with versions 1.1
2973 // If we are running with earlier version, which did not have symbol versions,
2974 // we should use the base version.
2975 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2976 void *f = dlvsym(handle, name, "libnuma_1.1");
2977 if (f == NULL) {
2978 f = dlsym(handle, name);
2979 }
2980 return f;
2981 }
2982
2983 bool os::Linux::libnuma_init() {
2984 // sched_getcpu() should be in libc.
2985 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2986 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2987
2988 // If it's not, try a direct syscall.
2989 if (sched_getcpu() == -1)
2990 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2991
2992 if (sched_getcpu() != -1) { // Does it work?
2993 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2994 if (handle != NULL) {
2995 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2996 libnuma_dlsym(handle, "numa_node_to_cpus")));
2997 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2998 libnuma_dlsym(handle, "numa_max_node")));
2999 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3000 libnuma_dlsym(handle, "numa_available")));
3001 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3002 libnuma_dlsym(handle, "numa_tonode_memory")));
3003 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3004 libnuma_dlsym(handle, "numa_interleave_memory")));
3005
3006
3007 if (numa_available() != -1) {
3008 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3009 // Create a cpu -> node mapping
3010 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3011 rebuild_cpu_to_node_map();
3012 return true;
3013 }
3014 }
3015 }
3016 return false;
3017 }
3018
3019 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3020 // The table is later used in get_node_by_cpu().
3021 void os::Linux::rebuild_cpu_to_node_map() {
3022 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3023 // in libnuma (possible values are starting from 16,
3024 // and continuing up with every other power of 2, but less
3025 // than the maximum number of CPUs supported by kernel), and
3026 // is a subject to change (in libnuma version 2 the requirements
3027 // are more reasonable) we'll just hardcode the number they use
3028 // in the library.
3029 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3030
3031 size_t cpu_num = os::active_processor_count();
3032 size_t cpu_map_size = NCPUS / BitsPerCLong;
3033 size_t cpu_map_valid_size =
3034 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3035
3036 cpu_to_node()->clear();
3037 cpu_to_node()->at_grow(cpu_num - 1);
3038 size_t node_num = numa_get_groups_num();
3039
3040 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3041 for (size_t i = 0; i < node_num; i++) {
3042 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3043 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3044 if (cpu_map[j] != 0) {
3045 for (size_t k = 0; k < BitsPerCLong; k++) {
3046 if (cpu_map[j] & (1UL << k)) {
3047 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
3048 }
3049 }
3050 }
3051 }
3052 }
3053 }
3054 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
3055 }
3056
3057 int os::Linux::get_node_by_cpu(int cpu_id) {
3058 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3059 return cpu_to_node()->at(cpu_id);
3060 }
3061 return -1;
3062 }
3063
3064 GrowableArray<int>* os::Linux::_cpu_to_node;
3065 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3066 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3067 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3068 os::Linux::numa_available_func_t os::Linux::_numa_available;
3069 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3070 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3071 unsigned long* os::Linux::_numa_all_nodes;
3072
3073 bool os::pd_uncommit_memory(char* addr, size_t size) {
3074 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3075 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3076 return res != (uintptr_t) MAP_FAILED;
3077 }
3078
3079 static
3080 address get_stack_commited_bottom(address bottom, size_t size) {
3081 address nbot = bottom;
3082 address ntop = bottom + size;
3083
3084 size_t page_sz = os::vm_page_size();
3085 unsigned pages = size / page_sz;
3086
3087 unsigned char vec[1];
3088 unsigned imin = 1, imax = pages + 1, imid;
3089 int mincore_return_value;
3090
3091 while (imin < imax) {
3092 imid = (imax + imin) / 2;
3093 nbot = ntop - (imid * page_sz);
3094
3095 // Use a trick with mincore to check whether the page is mapped or not.
3096 // mincore sets vec to 1 if page resides in memory and to 0 if page
3097 // is swapped output but if page we are asking for is unmapped
3098 // it returns -1,ENOMEM
3099 mincore_return_value = mincore(nbot, page_sz, vec);
3100
3101 if (mincore_return_value == -1) {
3102 // Page is not mapped go up
3103 // to find first mapped page
3104 if (errno != EAGAIN) {
3105 assert(errno == ENOMEM, "Unexpected mincore errno");
3106 imax = imid;
3107 }
3108 } else {
3109 // Page is mapped go down
3110 // to find first not mapped page
3111 imin = imid + 1;
3112 }
3113 }
3114
3115 nbot = nbot + page_sz;
3116
3117 // Adjust stack bottom one page up if last checked page is not mapped
3118 if (mincore_return_value == -1) {
3119 nbot = nbot + page_sz;
3120 }
3121
3122 return nbot;
3123 }
3124
3125
3126 // Linux uses a growable mapping for the stack, and if the mapping for
3127 // the stack guard pages is not removed when we detach a thread the
3128 // stack cannot grow beyond the pages where the stack guard was
3129 // mapped. If at some point later in the process the stack expands to
3130 // that point, the Linux kernel cannot expand the stack any further
3131 // because the guard pages are in the way, and a segfault occurs.
3132 //
3133 // However, it's essential not to split the stack region by unmapping
3134 // a region (leaving a hole) that's already part of the stack mapping,
3135 // so if the stack mapping has already grown beyond the guard pages at
3136 // the time we create them, we have to truncate the stack mapping.
3137 // So, we need to know the extent of the stack mapping when
3138 // create_stack_guard_pages() is called.
3139
3140 // We only need this for stacks that are growable: at the time of
3141 // writing thread stacks don't use growable mappings (i.e. those
3142 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3143 // only applies to the main thread.
3144
3145 // If the (growable) stack mapping already extends beyond the point
3146 // where we're going to put our guard pages, truncate the mapping at
3147 // that point by munmap()ping it. This ensures that when we later
3148 // munmap() the guard pages we don't leave a hole in the stack
3149 // mapping. This only affects the main/initial thread
3150
3151 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3152
3153 if (os::Linux::is_initial_thread()) {
3154 // As we manually grow stack up to bottom inside create_attached_thread(),
3155 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3156 // we don't need to do anything special.
3157 // Check it first, before calling heavy function.
3158 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3159 unsigned char vec[1];
3160
3161 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3162 // Fallback to slow path on all errors, including EAGAIN
3163 stack_extent = (uintptr_t) get_stack_commited_bottom(
3164 os::Linux::initial_thread_stack_bottom(),
3165 (size_t)addr - stack_extent);
3166 }
3167
3168 if (stack_extent < (uintptr_t)addr) {
3169 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3170 }
3171 }
3172
3173 return os::commit_memory(addr, size, !ExecMem);
3174 }
3175
3176 // If this is a growable mapping, remove the guard pages entirely by
3177 // munmap()ping them. If not, just call uncommit_memory(). This only
3178 // affects the main/initial thread, but guard against future OS changes
3179 // It's safe to always unmap guard pages for initial thread because we
3180 // always place it right after end of the mapped region
3181
3182 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3183 uintptr_t stack_extent, stack_base;
3184
3185 if (os::Linux::is_initial_thread()) {
3186 return ::munmap(addr, size) == 0;
3187 }
3188
3189 return os::uncommit_memory(addr, size);
3190 }
3191
3192 static address _highest_vm_reserved_address = NULL;
3193
3194 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3195 // at 'requested_addr'. If there are existing memory mappings at the same
3196 // location, however, they will be overwritten. If 'fixed' is false,
3197 // 'requested_addr' is only treated as a hint, the return value may or
3198 // may not start from the requested address. Unlike Linux mmap(), this
3199 // function returns NULL to indicate failure.
3200 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3201 char * addr;
3202 int flags;
3203
3204 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3205 if (fixed) {
3206 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3207 flags |= MAP_FIXED;
3208 }
3209
3210 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
3211 // to PROT_EXEC if executable when we commit the page.
3212 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
3213 flags, -1, 0);
3214
3215 if (addr != MAP_FAILED) {
3216 // anon_mmap() should only get called during VM initialization,
3217 // don't need lock (actually we can skip locking even it can be called
3218 // from multiple threads, because _highest_vm_reserved_address is just a
3219 // hint about the upper limit of non-stack memory regions.)
3220 if ((address)addr + bytes > _highest_vm_reserved_address) {
3221 _highest_vm_reserved_address = (address)addr + bytes;
3222 }
3223 }
3224
3225 return addr == MAP_FAILED ? NULL : addr;
3226 }
3227
3228 // Don't update _highest_vm_reserved_address, because there might be memory
3229 // regions above addr + size. If so, releasing a memory region only creates
3230 // a hole in the address space, it doesn't help prevent heap-stack collision.
3231 //
3232 static int anon_munmap(char * addr, size_t size) {
3233 return ::munmap(addr, size) == 0;
3234 }
3235
3236 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3237 size_t alignment_hint) {
3238 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3239 }
3240
3241 bool os::pd_release_memory(char* addr, size_t size) {
3242 return anon_munmap(addr, size);
3243 }
3244
3245 static address highest_vm_reserved_address() {
3246 return _highest_vm_reserved_address;
3247 }
3248
3249 static bool linux_mprotect(char* addr, size_t size, int prot) {
3250 // Linux wants the mprotect address argument to be page aligned.
3251 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3252
3253 // According to SUSv3, mprotect() should only be used with mappings
3254 // established by mmap(), and mmap() always maps whole pages. Unaligned
3255 // 'addr' likely indicates problem in the VM (e.g. trying to change
3256 // protection of malloc'ed or statically allocated memory). Check the
3257 // caller if you hit this assert.
3258 assert(addr == bottom, "sanity check");
3259
3260 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3261 return ::mprotect(bottom, size, prot) == 0;
3262 }
3263
3264 // Set protections specified
3265 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3266 bool is_committed) {
3267 unsigned int p = 0;
3268 switch (prot) {
3269 case MEM_PROT_NONE: p = PROT_NONE; break;
3270 case MEM_PROT_READ: p = PROT_READ; break;
3271 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3272 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3273 default:
3274 ShouldNotReachHere();
3275 }
3276 // is_committed is unused.
3277 return linux_mprotect(addr, bytes, p);
3278 }
3279
3280 bool os::guard_memory(char* addr, size_t size) {
3281 return linux_mprotect(addr, size, PROT_NONE);
3282 }
3283
3284 bool os::unguard_memory(char* addr, size_t size) {
3285 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3286 }
3287
3288 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3289 bool result = false;
3290 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3291 MAP_ANONYMOUS|MAP_PRIVATE,
3292 -1, 0);
3293 if (p != MAP_FAILED) {
3294 void *aligned_p = align_ptr_up(p, page_size);
3295
3296 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3297
3298 munmap(p, page_size * 2);
3299 }
3300
3301 if (warn && !result) {
3302 warning("TransparentHugePages is not supported by the operating system.");
3303 }
3304
3305 return result;
3306 }
3307
3308 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3309 bool result = false;
3310 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3311 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3312 -1, 0);
3313
3314 if (p != MAP_FAILED) {
3315 // We don't know if this really is a huge page or not.
3316 FILE *fp = fopen("/proc/self/maps", "r");
3317 if (fp) {
3318 while (!feof(fp)) {
3319 char chars[257];
3320 long x = 0;
3321 if (fgets(chars, sizeof(chars), fp)) {
3322 if (sscanf(chars, "%lx-%*x", &x) == 1
3323 && x == (long)p) {
3324 if (strstr (chars, "hugepage")) {
3325 result = true;
3326 break;
3327 }
3328 }
3329 }
3330 }
3331 fclose(fp);
3332 }
3333 munmap(p, page_size);
3334 }
3335
3336 if (warn && !result) {
3337 warning("HugeTLBFS is not supported by the operating system.");
3338 }
3339
3340 return result;
3341 }
3342
3343 /*
3344 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3345 *
3346 * From the coredump_filter documentation:
3347 *
3348 * - (bit 0) anonymous private memory
3349 * - (bit 1) anonymous shared memory
3350 * - (bit 2) file-backed private memory
3351 * - (bit 3) file-backed shared memory
3352 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3353 * effective only if the bit 2 is cleared)
3354 * - (bit 5) hugetlb private memory
3355 * - (bit 6) hugetlb shared memory
3356 */
3357 static void set_coredump_filter(void) {
3358 FILE *f;
3359 long cdm;
3360
3361 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3362 return;
3363 }
3364
3365 if (fscanf(f, "%lx", &cdm) != 1) {
3366 fclose(f);
3367 return;
3368 }
3369
3370 rewind(f);
3371
3372 if ((cdm & LARGEPAGES_BIT) == 0) {
3373 cdm |= LARGEPAGES_BIT;
3374 fprintf(f, "%#lx", cdm);
3375 }
3376
3377 fclose(f);
3378 }
3379
3380 // Large page support
3381
3382 static size_t _large_page_size = 0;
3383
3384 size_t os::Linux::find_large_page_size() {
3385 size_t large_page_size = 0;
3386
3387 // large_page_size on Linux is used to round up heap size. x86 uses either
3388 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3389 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3390 // page as large as 256M.
3391 //
3392 // Here we try to figure out page size by parsing /proc/meminfo and looking
3393 // for a line with the following format:
3394 // Hugepagesize: 2048 kB
3395 //
3396 // If we can't determine the value (e.g. /proc is not mounted, or the text
3397 // format has been changed), we'll use the largest page size supported by
3398 // the processor.
3399
3400 #ifndef ZERO
3401 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3402 ARM_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M);
3403 #endif // ZERO
3404
3405 FILE *fp = fopen("/proc/meminfo", "r");
3406 if (fp) {
3407 while (!feof(fp)) {
3408 int x = 0;
3409 char buf[16];
3410 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3411 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3412 large_page_size = x * K;
3413 break;
3414 }
3415 } else {
3416 // skip to next line
3417 for (;;) {
3418 int ch = fgetc(fp);
3419 if (ch == EOF || ch == (int)'\n') break;
3420 }
3421 }
3422 }
3423 fclose(fp);
3424 }
3425
3426 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3427 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3428 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3429 proper_unit_for_byte_size(large_page_size));
3430 }
3431
3432 return large_page_size;
3433 }
3434
3435 size_t os::Linux::setup_large_page_size() {
3436 _large_page_size = Linux::find_large_page_size();
3437 const size_t default_page_size = (size_t)Linux::page_size();
3438 if (_large_page_size > default_page_size) {
3439 _page_sizes[0] = _large_page_size;
3440 _page_sizes[1] = default_page_size;
3441 _page_sizes[2] = 0;
3442 }
3443
3444 return _large_page_size;
3445 }
3446
3447 bool os::Linux::setup_large_page_type(size_t page_size) {
3448 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3449 FLAG_IS_DEFAULT(UseSHM) &&
3450 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3451
3452 // The type of large pages has not been specified by the user.
3453
3454 // Try UseHugeTLBFS and then UseSHM.
3455 UseHugeTLBFS = UseSHM = true;
3456
3457 // Don't try UseTransparentHugePages since there are known
3458 // performance issues with it turned on. This might change in the future.
3459 UseTransparentHugePages = false;
3460 }
3461
3462 if (UseTransparentHugePages) {
3463 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3464 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3465 UseHugeTLBFS = false;
3466 UseSHM = false;
3467 return true;
3468 }
3469 UseTransparentHugePages = false;
3470 }
3471
3472 if (UseHugeTLBFS) {
3473 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3474 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3475 UseSHM = false;
3476 return true;
3477 }
3478 UseHugeTLBFS = false;
3479 }
3480
3481 return UseSHM;
3482 }
3483
3484 void os::large_page_init() {
3485 if (!UseLargePages &&
3486 !UseTransparentHugePages &&
3487 !UseHugeTLBFS &&
3488 !UseSHM) {
3489 // Not using large pages.
3490 return;
3491 }
3492
3493 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3494 // The user explicitly turned off large pages.
3495 // Ignore the rest of the large pages flags.
3496 UseTransparentHugePages = false;
3497 UseHugeTLBFS = false;
3498 UseSHM = false;
3499 return;
3500 }
3501
3502 size_t large_page_size = Linux::setup_large_page_size();
3503 UseLargePages = Linux::setup_large_page_type(large_page_size);
3504
3505 set_coredump_filter();
3506 }
3507
3508 #ifndef SHM_HUGETLB
3509 #define SHM_HUGETLB 04000
3510 #endif
3511
3512 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3513 // "exec" is passed in but not used. Creating the shared image for
3514 // the code cache doesn't have an SHM_X executable permission to check.
3515 assert(UseLargePages && UseSHM, "only for SHM large pages");
3516 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3517
3518 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3519 return NULL; // Fallback to small pages.
3520 }
3521
3522 key_t key = IPC_PRIVATE;
3523 char *addr;
3524
3525 bool warn_on_failure = UseLargePages &&
3526 (!FLAG_IS_DEFAULT(UseLargePages) ||
3527 !FLAG_IS_DEFAULT(UseSHM) ||
3528 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3529 );
3530 char msg[128];
3531
3532 // Create a large shared memory region to attach to based on size.
3533 // Currently, size is the total size of the heap
3534 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3535 if (shmid == -1) {
3536 // Possible reasons for shmget failure:
3537 // 1. shmmax is too small for Java heap.
3538 // > check shmmax value: cat /proc/sys/kernel/shmmax
3539 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3540 // 2. not enough large page memory.
3541 // > check available large pages: cat /proc/meminfo
3542 // > increase amount of large pages:
3543 // echo new_value > /proc/sys/vm/nr_hugepages
3544 // Note 1: different Linux may use different name for this property,
3545 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3546 // Note 2: it's possible there's enough physical memory available but
3547 // they are so fragmented after a long run that they can't
3548 // coalesce into large pages. Try to reserve large pages when
3549 // the system is still "fresh".
3550 if (warn_on_failure) {
3551 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3552 warning(msg);
3553 }
3554 return NULL;
3555 }
3556
3557 // attach to the region
3558 addr = (char*)shmat(shmid, req_addr, 0);
3559 int err = errno;
3560
3561 // Remove shmid. If shmat() is successful, the actual shared memory segment
3562 // will be deleted when it's detached by shmdt() or when the process
3563 // terminates. If shmat() is not successful this will remove the shared
3564 // segment immediately.
3565 shmctl(shmid, IPC_RMID, NULL);
3566
3567 if ((intptr_t)addr == -1) {
3568 if (warn_on_failure) {
3569 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3570 warning(msg);
3571 }
3572 return NULL;
3573 }
3574
3575 return addr;
3576 }
3577
3578 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3579 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3580
3581 bool warn_on_failure = UseLargePages &&
3582 (!FLAG_IS_DEFAULT(UseLargePages) ||
3583 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3584 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3585
3586 if (warn_on_failure) {
3587 char msg[128];
3588 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3589 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3590 warning(msg);
3591 }
3592 }
3593
3594 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3595 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3596 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3597 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3598
3599 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3600 char* addr = (char*)::mmap(req_addr, bytes, prot,
3601 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3602 -1, 0);
3603
3604 if (addr == MAP_FAILED) {
3605 warn_on_large_pages_failure(req_addr, bytes, errno);
3606 return NULL;
3607 }
3608
3609 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3610
3611 return addr;
3612 }
3613
3614 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3615 size_t large_page_size = os::large_page_size();
3616
3617 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3618
3619 // Allocate small pages.
3620
3621 char* start;
3622 if (req_addr != NULL) {
3623 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3624 assert(is_size_aligned(bytes, alignment), "Must be");
3625 start = os::reserve_memory(bytes, req_addr);
3626 assert(start == NULL || start == req_addr, "Must be");
3627 } else {
3628 start = os::reserve_memory_aligned(bytes, alignment);
3629 }
3630
3631 if (start == NULL) {
3632 return NULL;
3633 }
3634
3635 assert(is_ptr_aligned(start, alignment), "Must be");
3636
3637 // os::reserve_memory_special will record this memory area.
3638 // Need to release it here to prevent overlapping reservations.
3639 MemTracker::record_virtual_memory_release((address)start, bytes);
3640
3641 char* end = start + bytes;
3642
3643 // Find the regions of the allocated chunk that can be promoted to large pages.
3644 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3645 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3646
3647 size_t lp_bytes = lp_end - lp_start;
3648
3649 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3650
3651 if (lp_bytes == 0) {
3652 // The mapped region doesn't even span the start and the end of a large page.
3653 // Fall back to allocate a non-special area.
3654 ::munmap(start, end - start);
3655 return NULL;
3656 }
3657
3658 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3659
3660
3661 void* result;
3662
3663 if (start != lp_start) {
3664 result = ::mmap(start, lp_start - start, prot,
3665 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3666 -1, 0);
3667 if (result == MAP_FAILED) {
3668 ::munmap(lp_start, end - lp_start);
3669 return NULL;
3670 }
3671 }
3672
3673 result = ::mmap(lp_start, lp_bytes, prot,
3674 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3675 -1, 0);
3676 if (result == MAP_FAILED) {
3677 warn_on_large_pages_failure(req_addr, bytes, errno);
3678 // If the mmap above fails, the large pages region will be unmapped and we
3679 // have regions before and after with small pages. Release these regions.
3680 //
3681 // | mapped | unmapped | mapped |
3682 // ^ ^ ^ ^
3683 // start lp_start lp_end end
3684 //
3685 ::munmap(start, lp_start - start);
3686 ::munmap(lp_end, end - lp_end);
3687 return NULL;
3688 }
3689
3690 if (lp_end != end) {
3691 result = ::mmap(lp_end, end - lp_end, prot,
3692 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3693 -1, 0);
3694 if (result == MAP_FAILED) {
3695 ::munmap(start, lp_end - start);
3696 return NULL;
3697 }
3698 }
3699
3700 return start;
3701 }
3702
3703 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3704 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3705 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3706 assert(is_power_of_2(alignment), "Must be");
3707 assert(is_power_of_2(os::large_page_size()), "Must be");
3708 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3709
3710 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3711 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3712 } else {
3713 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3714 }
3715 }
3716
3717 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3718 assert(UseLargePages, "only for large pages");
3719
3720 char* addr;
3721 if (UseSHM) {
3722 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3723 } else {
3724 assert(UseHugeTLBFS, "must be");
3725 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3726 }
3727
3728 if (addr != NULL) {
3729 if (UseNUMAInterleaving) {
3730 numa_make_global(addr, bytes);
3731 }
3732
3733 // The memory is committed
3734 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, mtNone, CALLER_PC);
3735 }
3736
3737 return addr;
3738 }
3739
3740 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3741 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3742 return shmdt(base) == 0;
3743 }
3744
3745 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3746 return pd_release_memory(base, bytes);
3747 }
3748
3749 bool os::release_memory_special(char* base, size_t bytes) {
3750 assert(UseLargePages, "only for large pages");
3751
3752 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3753
3754 bool res;
3755 if (UseSHM) {
3756 res = os::Linux::release_memory_special_shm(base, bytes);
3757 } else {
3758 assert(UseHugeTLBFS, "must be");
3759 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3760 }
3761
3762 if (res) {
3763 tkr.record((address)base, bytes);
3764 } else {
3765 tkr.discard();
3766 }
3767
3768 return res;
3769 }
3770
3771
3772 size_t os::large_page_size() {
3773 return _large_page_size;
3774 }
3775
3776 // With SysV SHM the entire memory region must be allocated as shared
3777 // memory.
3778 // HugeTLBFS allows application to commit large page memory on demand.
3779 // However, when committing memory with HugeTLBFS fails, the region
3780 // that was supposed to be committed will lose the old reservation
3781 // and allow other threads to steal that memory region. Because of this
3782 // behavior we can't commit HugeTLBFS memory.
3783 bool os::can_commit_large_page_memory() {
3784 return UseTransparentHugePages;
3785 }
3786
3787 bool os::can_execute_large_page_memory() {
3788 return UseTransparentHugePages || UseHugeTLBFS;
3789 }
3790
3791 // Reserve memory at an arbitrary address, only if that area is
3792 // available (and not reserved for something else).
3793
3794 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3795 const int max_tries = 10;
3796 char* base[max_tries];
3797 size_t size[max_tries];
3798 const size_t gap = 0x000000;
3799
3800 // Assert only that the size is a multiple of the page size, since
3801 // that's all that mmap requires, and since that's all we really know
3802 // about at this low abstraction level. If we need higher alignment,
3803 // we can either pass an alignment to this method or verify alignment
3804 // in one of the methods further up the call chain. See bug 5044738.
3805 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3806
3807 // Repeatedly allocate blocks until the block is allocated at the
3808 // right spot. Give up after max_tries. Note that reserve_memory() will
3809 // automatically update _highest_vm_reserved_address if the call is
3810 // successful. The variable tracks the highest memory address every reserved
3811 // by JVM. It is used to detect heap-stack collision if running with
3812 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3813 // space than needed, it could confuse the collision detecting code. To
3814 // solve the problem, save current _highest_vm_reserved_address and
3815 // calculate the correct value before return.
3816 address old_highest = _highest_vm_reserved_address;
3817
3818 // Linux mmap allows caller to pass an address as hint; give it a try first,
3819 // if kernel honors the hint then we can return immediately.
3820 char * addr = anon_mmap(requested_addr, bytes, false);
3821 if (addr == requested_addr) {
3822 return requested_addr;
3823 }
3824
3825 if (addr != NULL) {
3826 // mmap() is successful but it fails to reserve at the requested address
3827 anon_munmap(addr, bytes);
3828 }
3829
3830 int i;
3831 for (i = 0; i < max_tries; ++i) {
3832 base[i] = reserve_memory(bytes);
3833
3834 if (base[i] != NULL) {
3835 // Is this the block we wanted?
3836 if (base[i] == requested_addr) {
3837 size[i] = bytes;
3838 break;
3839 }
3840
3841 // Does this overlap the block we wanted? Give back the overlapped
3842 // parts and try again.
3843
3844 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3845 if (top_overlap >= 0 && top_overlap < bytes) {
3846 unmap_memory(base[i], top_overlap);
3847 base[i] += top_overlap;
3848 size[i] = bytes - top_overlap;
3849 } else {
3850 size_t bottom_overlap = base[i] + bytes - requested_addr;
3851 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3852 unmap_memory(requested_addr, bottom_overlap);
3853 size[i] = bytes - bottom_overlap;
3854 } else {
3855 size[i] = bytes;
3856 }
3857 }
3858 }
3859 }
3860
3861 // Give back the unused reserved pieces.
3862
3863 for (int j = 0; j < i; ++j) {
3864 if (base[j] != NULL) {
3865 unmap_memory(base[j], size[j]);
3866 }
3867 }
3868
3869 if (i < max_tries) {
3870 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3871 return requested_addr;
3872 } else {
3873 _highest_vm_reserved_address = old_highest;
3874 return NULL;
3875 }
3876 }
3877
3878 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3879 return ::read(fd, buf, nBytes);
3880 }
3881
3882 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3883 // Solaris uses poll(), linux uses park().
3884 // Poll() is likely a better choice, assuming that Thread.interrupt()
3885 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3886 // SIGSEGV, see 4355769.
3887
3888 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3889 assert(thread == Thread::current(), "thread consistency check");
3890
3891 ParkEvent * const slp = thread->_SleepEvent ;
3892 slp->reset() ;
3893 OrderAccess::fence() ;
3894
3895 if (interruptible) {
3896 jlong prevtime = javaTimeNanos();
3897
3898 for (;;) {
3899 if (os::is_interrupted(thread, true)) {
3900 return OS_INTRPT;
3901 }
3902
3903 jlong newtime = javaTimeNanos();
3904
3905 if (newtime - prevtime < 0) {
3906 // time moving backwards, should only happen if no monotonic clock
3907 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3908 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3909 } else {
3910 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3911 }
3912
3913 if(millis <= 0) {
3914 return OS_OK;
3915 }
3916
3917 prevtime = newtime;
3918
3919 {
3920 assert(thread->is_Java_thread(), "sanity check");
3921 JavaThread *jt = (JavaThread *) thread;
3922 ThreadBlockInVM tbivm(jt);
3923 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3924
3925 jt->set_suspend_equivalent();
3926 // cleared by handle_special_suspend_equivalent_condition() or
3927 // java_suspend_self() via check_and_wait_while_suspended()
3928
3929 slp->park(millis);
3930
3931 // were we externally suspended while we were waiting?
3932 jt->check_and_wait_while_suspended();
3933 }
3934 }
3935 } else {
3936 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3937 jlong prevtime = javaTimeNanos();
3938
3939 for (;;) {
3940 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3941 // the 1st iteration ...
3942 jlong newtime = javaTimeNanos();
3943
3944 if (newtime - prevtime < 0) {
3945 // time moving backwards, should only happen if no monotonic clock
3946 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3947 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3948 } else {
3949 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3950 }
3951
3952 if(millis <= 0) break ;
3953
3954 prevtime = newtime;
3955 slp->park(millis);
3956 }
3957 return OS_OK ;
3958 }
3959 }
3960
3961 //
3962 // Short sleep, direct OS call.
3963 //
3964 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3965 // sched_yield(2) will actually give up the CPU:
3966 //
3967 // * Alone on this pariticular CPU, keeps running.
3968 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3969 // (pre 2.6.39).
3970 //
3971 // So calling this with 0 is an alternative.
3972 //
3973 void os::naked_short_sleep(jlong ms) {
3974 struct timespec req;
3975
3976 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3977 req.tv_sec = 0;
3978 if (ms > 0) {
3979 req.tv_nsec = (ms % 1000) * 1000000;
3980 }
3981 else {
3982 req.tv_nsec = 1;
3983 }
3984
3985 nanosleep(&req, NULL);
3986
3987 return;
3988 }
3989
3990 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3991 void os::infinite_sleep() {
3992 while (true) { // sleep forever ...
3993 ::sleep(100); // ... 100 seconds at a time
3994 }
3995 }
3996
3997 // Used to convert frequent JVM_Yield() to nops
3998 bool os::dont_yield() {
3999 return DontYieldALot;
4000 }
4001
4002 void os::yield() {
4003 sched_yield();
4004 }
4005
4006 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
4007
4008 void os::yield_all(int attempts) {
4009 // Yields to all threads, including threads with lower priorities
4010 // Threads on Linux are all with same priority. The Solaris style
4011 // os::yield_all() with nanosleep(1ms) is not necessary.
4012 sched_yield();
4013 }
4014
4015 // Called from the tight loops to possibly influence time-sharing heuristics
4016 void os::loop_breaker(int attempts) {
4017 os::yield_all(attempts);
4018 }
4019
4020 ////////////////////////////////////////////////////////////////////////////////
4021 // thread priority support
4022
4023 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4024 // only supports dynamic priority, static priority must be zero. For real-time
4025 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4026 // However, for large multi-threaded applications, SCHED_RR is not only slower
4027 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4028 // of 5 runs - Sep 2005).
4029 //
4030 // The following code actually changes the niceness of kernel-thread/LWP. It
4031 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4032 // not the entire user process, and user level threads are 1:1 mapped to kernel
4033 // threads. It has always been the case, but could change in the future. For
4034 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4035 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
4036
4037 int os::java_to_os_priority[CriticalPriority + 1] = {
4038 19, // 0 Entry should never be used
4039
4040 4, // 1 MinPriority
4041 3, // 2
4042 2, // 3
4043
4044 1, // 4
4045 0, // 5 NormPriority
4046 -1, // 6
4047
4048 -2, // 7
4049 -3, // 8
4050 -4, // 9 NearMaxPriority
4051
4052 -5, // 10 MaxPriority
4053
4054 -5 // 11 CriticalPriority
4055 };
4056
4057 static int prio_init() {
4058 if (ThreadPriorityPolicy == 1) {
4059 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
4060 // if effective uid is not root. Perhaps, a more elegant way of doing
4061 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
4062 if (geteuid() != 0) {
4063 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4064 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
4065 }
4066 ThreadPriorityPolicy = 0;
4067 }
4068 }
4069 if (UseCriticalJavaThreadPriority) {
4070 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4071 }
4072 return 0;
4073 }
4074
4075 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4076 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
4077
4078 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4079 return (ret == 0) ? OS_OK : OS_ERR;
4080 }
4081
4082 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
4083 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
4084 *priority_ptr = java_to_os_priority[NormPriority];
4085 return OS_OK;
4086 }
4087
4088 errno = 0;
4089 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4090 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4091 }
4092
4093 // Hint to the underlying OS that a task switch would not be good.
4094 // Void return because it's a hint and can fail.
4095 void os::hint_no_preempt() {}
4096
4097 ////////////////////////////////////////////////////////////////////////////////
4098 // suspend/resume support
4099
4100 // the low-level signal-based suspend/resume support is a remnant from the
4101 // old VM-suspension that used to be for java-suspension, safepoints etc,
4102 // within hotspot. Now there is a single use-case for this:
4103 // - calling get_thread_pc() on the VMThread by the flat-profiler task
4104 // that runs in the watcher thread.
4105 // The remaining code is greatly simplified from the more general suspension
4106 // code that used to be used.
4107 //
4108 // The protocol is quite simple:
4109 // - suspend:
4110 // - sends a signal to the target thread
4111 // - polls the suspend state of the osthread using a yield loop
4112 // - target thread signal handler (SR_handler) sets suspend state
4113 // and blocks in sigsuspend until continued
4114 // - resume:
4115 // - sets target osthread state to continue
4116 // - sends signal to end the sigsuspend loop in the SR_handler
4117 //
4118 // Note that the SR_lock plays no role in this suspend/resume protocol.
4119 //
4120
4121 static void resume_clear_context(OSThread *osthread) {
4122 osthread->set_ucontext(NULL);
4123 osthread->set_siginfo(NULL);
4124 }
4125
4126 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
4127 osthread->set_ucontext(context);
4128 osthread->set_siginfo(siginfo);
4129 }
4130
4131 //
4132 // Handler function invoked when a thread's execution is suspended or
4133 // resumed. We have to be careful that only async-safe functions are
4134 // called here (Note: most pthread functions are not async safe and
4135 // should be avoided.)
4136 //
4137 // Note: sigwait() is a more natural fit than sigsuspend() from an
4138 // interface point of view, but sigwait() prevents the signal hander
4139 // from being run. libpthread would get very confused by not having
4140 // its signal handlers run and prevents sigwait()'s use with the
4141 // mutex granting granting signal.
4142 //
4143 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4144 //
4145 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4146 // Save and restore errno to avoid confusing native code with EINTR
4147 // after sigsuspend.
4148 int old_errno = errno;
4149
4150 Thread* thread = Thread::current();
4151 OSThread* osthread = thread->osthread();
4152 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4153
4154 os::SuspendResume::State current = osthread->sr.state();
4155 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4156 suspend_save_context(osthread, siginfo, context);
4157
4158 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4159 os::SuspendResume::State state = osthread->sr.suspended();
4160 if (state == os::SuspendResume::SR_SUSPENDED) {
4161 sigset_t suspend_set; // signals for sigsuspend()
4162
4163 // get current set of blocked signals and unblock resume signal
4164 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4165 sigdelset(&suspend_set, SR_signum);
4166
4167 sr_semaphore.signal();
4168 // wait here until we are resumed
4169 while (1) {
4170 sigsuspend(&suspend_set);
4171
4172 os::SuspendResume::State result = osthread->sr.running();
4173 if (result == os::SuspendResume::SR_RUNNING) {
4174 sr_semaphore.signal();
4175 break;
4176 }
4177 }
4178
4179 } else if (state == os::SuspendResume::SR_RUNNING) {
4180 // request was cancelled, continue
4181 } else {
4182 ShouldNotReachHere();
4183 }
4184
4185 resume_clear_context(osthread);
4186 } else if (current == os::SuspendResume::SR_RUNNING) {
4187 // request was cancelled, continue
4188 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4189 // ignore
4190 } else {
4191 // ignore
4192 }
4193
4194 errno = old_errno;
4195 }
4196
4197
4198 static int SR_initialize() {
4199 struct sigaction act;
4200 char *s;
4201 /* Get signal number to use for suspend/resume */
4202 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4203 int sig = ::strtol(s, 0, 10);
4204 if (sig > 0 || sig < _NSIG) {
4205 SR_signum = sig;
4206 }
4207 }
4208
4209 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4210 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4211
4212 sigemptyset(&SR_sigset);
4213 sigaddset(&SR_sigset, SR_signum);
4214
4215 /* Set up signal handler for suspend/resume */
4216 act.sa_flags = SA_RESTART|SA_SIGINFO;
4217 act.sa_handler = (void (*)(int)) SR_handler;
4218
4219 // SR_signum is blocked by default.
4220 // 4528190 - We also need to block pthread restart signal (32 on all
4221 // supported Linux platforms). Note that LinuxThreads need to block
4222 // this signal for all threads to work properly. So we don't have
4223 // to use hard-coded signal number when setting up the mask.
4224 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4225
4226 if (sigaction(SR_signum, &act, 0) == -1) {
4227 return -1;
4228 }
4229
4230 // Save signal flag
4231 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4232 return 0;
4233 }
4234
4235 static int SR_finalize() {
4236 return 0;
4237 }
4238
4239 static int sr_notify(OSThread* osthread) {
4240 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4241 assert_status(status == 0, status, "pthread_kill");
4242 return status;
4243 }
4244
4245 // "Randomly" selected value for how long we want to spin
4246 // before bailing out on suspending a thread, also how often
4247 // we send a signal to a thread we want to resume
4248 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4249 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4250
4251 // returns true on success and false on error - really an error is fatal
4252 // but this seems the normal response to library errors
4253 static bool do_suspend(OSThread* osthread) {
4254 assert(osthread->sr.is_running(), "thread should be running");
4255 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4256
4257 // mark as suspended and send signal
4258 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4259 // failed to switch, state wasn't running?
4260 ShouldNotReachHere();
4261 return false;
4262 }
4263
4264 if (sr_notify(osthread) != 0) {
4265 ShouldNotReachHere();
4266 }
4267
4268 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4269 while (true) {
4270 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4271 break;
4272 } else {
4273 // timeout
4274 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4275 if (cancelled == os::SuspendResume::SR_RUNNING) {
4276 return false;
4277 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4278 // make sure that we consume the signal on the semaphore as well
4279 sr_semaphore.wait();
4280 break;
4281 } else {
4282 ShouldNotReachHere();
4283 return false;
4284 }
4285 }
4286 }
4287
4288 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4289 return true;
4290 }
4291
4292 static void do_resume(OSThread* osthread) {
4293 assert(osthread->sr.is_suspended(), "thread should be suspended");
4294 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4295
4296 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4297 // failed to switch to WAKEUP_REQUEST
4298 ShouldNotReachHere();
4299 return;
4300 }
4301
4302 while (true) {
4303 if (sr_notify(osthread) == 0) {
4304 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4305 if (osthread->sr.is_running()) {
4306 return;
4307 }
4308 }
4309 } else {
4310 ShouldNotReachHere();
4311 }
4312 }
4313
4314 guarantee(osthread->sr.is_running(), "Must be running!");
4315 }
4316
4317 ////////////////////////////////////////////////////////////////////////////////
4318 // interrupt support
4319
4320 void os::interrupt(Thread* thread) {
4321 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4322 "possibility of dangling Thread pointer");
4323
4324 OSThread* osthread = thread->osthread();
4325
4326 if (!osthread->interrupted()) {
4327 osthread->set_interrupted(true);
4328 // More than one thread can get here with the same value of osthread,
4329 // resulting in multiple notifications. We do, however, want the store
4330 // to interrupted() to be visible to other threads before we execute unpark().
4331 OrderAccess::fence();
4332 ParkEvent * const slp = thread->_SleepEvent ;
4333 if (slp != NULL) slp->unpark() ;
4334 }
4335
4336 // For JSR166. Unpark even if interrupt status already was set
4337 if (thread->is_Java_thread())
4338 ((JavaThread*)thread)->parker()->unpark();
4339
4340 ParkEvent * ev = thread->_ParkEvent ;
4341 if (ev != NULL) ev->unpark() ;
4342
4343 }
4344
4345 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
4346 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4347 "possibility of dangling Thread pointer");
4348
4349 OSThread* osthread = thread->osthread();
4350
4351 bool interrupted = osthread->interrupted();
4352
4353 if (interrupted && clear_interrupted) {
4354 osthread->set_interrupted(false);
4355 // consider thread->_SleepEvent->reset() ... optional optimization
4356 }
4357
4358 return interrupted;
4359 }
4360
4361 ///////////////////////////////////////////////////////////////////////////////////
4362 // signal handling (except suspend/resume)
4363
4364 // This routine may be used by user applications as a "hook" to catch signals.
4365 // The user-defined signal handler must pass unrecognized signals to this
4366 // routine, and if it returns true (non-zero), then the signal handler must
4367 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4368 // routine will never retun false (zero), but instead will execute a VM panic
4369 // routine kill the process.
4370 //
4371 // If this routine returns false, it is OK to call it again. This allows
4372 // the user-defined signal handler to perform checks either before or after
4373 // the VM performs its own checks. Naturally, the user code would be making
4374 // a serious error if it tried to handle an exception (such as a null check
4375 // or breakpoint) that the VM was generating for its own correct operation.
4376 //
4377 // This routine may recognize any of the following kinds of signals:
4378 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4379 // It should be consulted by handlers for any of those signals.
4380 //
4381 // The caller of this routine must pass in the three arguments supplied
4382 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4383 // field of the structure passed to sigaction(). This routine assumes that
4384 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4385 //
4386 // Note that the VM will print warnings if it detects conflicting signal
4387 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4388 //
4389 extern "C" JNIEXPORT int
4390 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4391 void* ucontext, int abort_if_unrecognized);
4392
4393 void signalHandler(int sig, siginfo_t* info, void* uc) {
4394 assert(info != NULL && uc != NULL, "it must be old kernel");
4395 JVM_handle_linux_signal(sig, info, uc, true);
4396 }
4397
4398
4399 // This boolean allows users to forward their own non-matching signals
4400 // to JVM_handle_linux_signal, harmlessly.
4401 bool os::Linux::signal_handlers_are_installed = false;
4402
4403 // For signal-chaining
4404 struct sigaction os::Linux::sigact[MAXSIGNUM];
4405 unsigned int os::Linux::sigs = 0;
4406 bool os::Linux::libjsig_is_loaded = false;
4407 typedef struct sigaction *(*get_signal_t)(int);
4408 get_signal_t os::Linux::get_signal_action = NULL;
4409
4410 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4411 struct sigaction *actp = NULL;
4412
4413 if (libjsig_is_loaded) {
4414 // Retrieve the old signal handler from libjsig
4415 actp = (*get_signal_action)(sig);
4416 }
4417 if (actp == NULL) {
4418 // Retrieve the preinstalled signal handler from jvm
4419 actp = get_preinstalled_handler(sig);
4420 }
4421
4422 return actp;
4423 }
4424
4425 static bool call_chained_handler(struct sigaction *actp, int sig,
4426 siginfo_t *siginfo, void *context) {
4427 // Call the old signal handler
4428 if (actp->sa_handler == SIG_DFL) {
4429 // It's more reasonable to let jvm treat it as an unexpected exception
4430 // instead of taking the default action.
4431 return false;
4432 } else if (actp->sa_handler != SIG_IGN) {
4433 if ((actp->sa_flags & SA_NODEFER) == 0) {
4434 // automaticlly block the signal
4435 sigaddset(&(actp->sa_mask), sig);
4436 }
4437
4438 sa_handler_t hand;
4439 sa_sigaction_t sa;
4440 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4441 // retrieve the chained handler
4442 if (siginfo_flag_set) {
4443 sa = actp->sa_sigaction;
4444 } else {
4445 hand = actp->sa_handler;
4446 }
4447
4448 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4449 actp->sa_handler = SIG_DFL;
4450 }
4451
4452 // try to honor the signal mask
4453 sigset_t oset;
4454 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4455
4456 // call into the chained handler
4457 if (siginfo_flag_set) {
4458 (*sa)(sig, siginfo, context);
4459 } else {
4460 (*hand)(sig);
4461 }
4462
4463 // restore the signal mask
4464 pthread_sigmask(SIG_SETMASK, &oset, 0);
4465 }
4466 // Tell jvm's signal handler the signal is taken care of.
4467 return true;
4468 }
4469
4470 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4471 bool chained = false;
4472 // signal-chaining
4473 if (UseSignalChaining) {
4474 struct sigaction *actp = get_chained_signal_action(sig);
4475 if (actp != NULL) {
4476 chained = call_chained_handler(actp, sig, siginfo, context);
4477 }
4478 }
4479 return chained;
4480 }
4481
4482 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4483 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4484 return &sigact[sig];
4485 }
4486 return NULL;
4487 }
4488
4489 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4490 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4491 sigact[sig] = oldAct;
4492 sigs |= (unsigned int)1 << sig;
4493 }
4494
4495 // for diagnostic
4496 int os::Linux::sigflags[MAXSIGNUM];
4497
4498 int os::Linux::get_our_sigflags(int sig) {
4499 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4500 return sigflags[sig];
4501 }
4502
4503 void os::Linux::set_our_sigflags(int sig, int flags) {
4504 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4505 sigflags[sig] = flags;
4506 }
4507
4508 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4509 // Check for overwrite.
4510 struct sigaction oldAct;
4511 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4512
4513 void* oldhand = oldAct.sa_sigaction
4514 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4515 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4516 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4517 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4518 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4519 if (AllowUserSignalHandlers || !set_installed) {
4520 // Do not overwrite; user takes responsibility to forward to us.
4521 return;
4522 } else if (UseSignalChaining) {
4523 // save the old handler in jvm
4524 save_preinstalled_handler(sig, oldAct);
4525 // libjsig also interposes the sigaction() call below and saves the
4526 // old sigaction on it own.
4527 } else {
4528 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4529 "%#lx for signal %d.", (long)oldhand, sig));
4530 }
4531 }
4532
4533 struct sigaction sigAct;
4534 sigfillset(&(sigAct.sa_mask));
4535 sigAct.sa_handler = SIG_DFL;
4536 if (!set_installed) {
4537 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4538 } else {
4539 sigAct.sa_sigaction = signalHandler;
4540 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4541 }
4542 // Save flags, which are set by ours
4543 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4544 sigflags[sig] = sigAct.sa_flags;
4545
4546 int ret = sigaction(sig, &sigAct, &oldAct);
4547 assert(ret == 0, "check");
4548
4549 void* oldhand2 = oldAct.sa_sigaction
4550 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4551 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4552 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4553 }
4554
4555 // install signal handlers for signals that HotSpot needs to
4556 // handle in order to support Java-level exception handling.
4557
4558 void os::Linux::install_signal_handlers() {
4559 if (!signal_handlers_are_installed) {
4560 signal_handlers_are_installed = true;
4561
4562 // signal-chaining
4563 typedef void (*signal_setting_t)();
4564 signal_setting_t begin_signal_setting = NULL;
4565 signal_setting_t end_signal_setting = NULL;
4566 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4567 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4568 if (begin_signal_setting != NULL) {
4569 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4570 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4571 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4572 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4573 libjsig_is_loaded = true;
4574 assert(UseSignalChaining, "should enable signal-chaining");
4575 }
4576 if (libjsig_is_loaded) {
4577 // Tell libjsig jvm is setting signal handlers
4578 (*begin_signal_setting)();
4579 }
4580
4581 set_signal_handler(SIGSEGV, true);
4582 set_signal_handler(SIGPIPE, true);
4583 set_signal_handler(SIGBUS, true);
4584 set_signal_handler(SIGILL, true);
4585 set_signal_handler(SIGFPE, true);
4586 #if defined(PPC64)
4587 set_signal_handler(SIGTRAP, true);
4588 #endif
4589 set_signal_handler(SIGXFSZ, true);
4590
4591 if (libjsig_is_loaded) {
4592 // Tell libjsig jvm finishes setting signal handlers
4593 (*end_signal_setting)();
4594 }
4595
4596 // We don't activate signal checker if libjsig is in place, we trust ourselves
4597 // and if UserSignalHandler is installed all bets are off.
4598 // Log that signal checking is off only if -verbose:jni is specified.
4599 if (CheckJNICalls) {
4600 if (libjsig_is_loaded) {
4601 if (PrintJNIResolving) {
4602 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4603 }
4604 check_signals = false;
4605 }
4606 if (AllowUserSignalHandlers) {
4607 if (PrintJNIResolving) {
4608 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4609 }
4610 check_signals = false;
4611 }
4612 }
4613 }
4614 }
4615
4616 // This is the fastest way to get thread cpu time on Linux.
4617 // Returns cpu time (user+sys) for any thread, not only for current.
4618 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4619 // It might work on 2.6.10+ with a special kernel/glibc patch.
4620 // For reference, please, see IEEE Std 1003.1-2004:
4621 // http://www.unix.org/single_unix_specification
4622
4623 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4624 struct timespec tp;
4625 int rc = os::Linux::clock_gettime(clockid, &tp);
4626 assert(rc == 0, "clock_gettime is expected to return 0 code");
4627
4628 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4629 }
4630
4631 /////
4632 // glibc on Linux platform uses non-documented flag
4633 // to indicate, that some special sort of signal
4634 // trampoline is used.
4635 // We will never set this flag, and we should
4636 // ignore this flag in our diagnostic
4637 #ifdef SIGNIFICANT_SIGNAL_MASK
4638 #undef SIGNIFICANT_SIGNAL_MASK
4639 #endif
4640 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4641
4642 static const char* get_signal_handler_name(address handler,
4643 char* buf, int buflen) {
4644 int offset;
4645 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4646 if (found) {
4647 // skip directory names
4648 const char *p1, *p2;
4649 p1 = buf;
4650 size_t len = strlen(os::file_separator());
4651 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4652 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4653 } else {
4654 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4655 }
4656 return buf;
4657 }
4658
4659 static void print_signal_handler(outputStream* st, int sig,
4660 char* buf, size_t buflen) {
4661 struct sigaction sa;
4662
4663 sigaction(sig, NULL, &sa);
4664
4665 // See comment for SIGNIFICANT_SIGNAL_MASK define
4666 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4667
4668 st->print("%s: ", os::exception_name(sig, buf, buflen));
4669
4670 address handler = (sa.sa_flags & SA_SIGINFO)
4671 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4672 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4673
4674 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4675 st->print("SIG_DFL");
4676 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4677 st->print("SIG_IGN");
4678 } else {
4679 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4680 }
4681
4682 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
4683
4684 address rh = VMError::get_resetted_sighandler(sig);
4685 // May be, handler was resetted by VMError?
4686 if(rh != NULL) {
4687 handler = rh;
4688 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4689 }
4690
4691 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
4692
4693 // Check: is it our handler?
4694 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4695 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4696 // It is our signal handler
4697 // check for flags, reset system-used one!
4698 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4699 st->print(
4700 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4701 os::Linux::get_our_sigflags(sig));
4702 }
4703 }
4704 st->cr();
4705 }
4706
4707
4708 #define DO_SIGNAL_CHECK(sig) \
4709 if (!sigismember(&check_signal_done, sig)) \
4710 os::Linux::check_signal_handler(sig)
4711
4712 // This method is a periodic task to check for misbehaving JNI applications
4713 // under CheckJNI, we can add any periodic checks here
4714
4715 void os::run_periodic_checks() {
4716
4717 if (check_signals == false) return;
4718
4719 // SEGV and BUS if overridden could potentially prevent
4720 // generation of hs*.log in the event of a crash, debugging
4721 // such a case can be very challenging, so we absolutely
4722 // check the following for a good measure:
4723 DO_SIGNAL_CHECK(SIGSEGV);
4724 DO_SIGNAL_CHECK(SIGILL);
4725 DO_SIGNAL_CHECK(SIGFPE);
4726 DO_SIGNAL_CHECK(SIGBUS);
4727 DO_SIGNAL_CHECK(SIGPIPE);
4728 DO_SIGNAL_CHECK(SIGXFSZ);
4729 #if defined(PPC64)
4730 DO_SIGNAL_CHECK(SIGTRAP);
4731 #endif
4732
4733 // ReduceSignalUsage allows the user to override these handlers
4734 // see comments at the very top and jvm_solaris.h
4735 if (!ReduceSignalUsage) {
4736 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4737 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4738 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4739 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4740 }
4741
4742 DO_SIGNAL_CHECK(SR_signum);
4743 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4744 }
4745
4746 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4747
4748 static os_sigaction_t os_sigaction = NULL;
4749
4750 void os::Linux::check_signal_handler(int sig) {
4751 char buf[O_BUFLEN];
4752 address jvmHandler = NULL;
4753
4754
4755 struct sigaction act;
4756 if (os_sigaction == NULL) {
4757 // only trust the default sigaction, in case it has been interposed
4758 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4759 if (os_sigaction == NULL) return;
4760 }
4761
4762 os_sigaction(sig, (struct sigaction*)NULL, &act);
4763
4764
4765 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4766
4767 address thisHandler = (act.sa_flags & SA_SIGINFO)
4768 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4769 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4770
4771
4772 switch(sig) {
4773 case SIGSEGV:
4774 case SIGBUS:
4775 case SIGFPE:
4776 case SIGPIPE:
4777 case SIGILL:
4778 case SIGXFSZ:
4779 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4780 break;
4781
4782 case SHUTDOWN1_SIGNAL:
4783 case SHUTDOWN2_SIGNAL:
4784 case SHUTDOWN3_SIGNAL:
4785 case BREAK_SIGNAL:
4786 jvmHandler = (address)user_handler();
4787 break;
4788
4789 case INTERRUPT_SIGNAL:
4790 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4791 break;
4792
4793 default:
4794 if (sig == SR_signum) {
4795 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4796 } else {
4797 return;
4798 }
4799 break;
4800 }
4801
4802 if (thisHandler != jvmHandler) {
4803 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4804 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4805 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4806 // No need to check this sig any longer
4807 sigaddset(&check_signal_done, sig);
4808 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4809 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4810 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4811 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4812 // No need to check this sig any longer
4813 sigaddset(&check_signal_done, sig);
4814 }
4815
4816 // Dump all the signal
4817 if (sigismember(&check_signal_done, sig)) {
4818 print_signal_handlers(tty, buf, O_BUFLEN);
4819 }
4820 }
4821
4822 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4823
4824 extern bool signal_name(int signo, char* buf, size_t len);
4825
4826 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4827 if (0 < exception_code && exception_code <= SIGRTMAX) {
4828 // signal
4829 if (!signal_name(exception_code, buf, size)) {
4830 jio_snprintf(buf, size, "SIG%d", exception_code);
4831 }
4832 return buf;
4833 } else {
4834 return NULL;
4835 }
4836 }
4837
4838 // this is called _before_ the most of global arguments have been parsed
4839 void os::init(void) {
4840 char dummy; /* used to get a guess on initial stack address */
4841 // first_hrtime = gethrtime();
4842
4843 // With LinuxThreads the JavaMain thread pid (primordial thread)
4844 // is different than the pid of the java launcher thread.
4845 // So, on Linux, the launcher thread pid is passed to the VM
4846 // via the sun.java.launcher.pid property.
4847 // Use this property instead of getpid() if it was correctly passed.
4848 // See bug 6351349.
4849 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4850
4851 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4852
4853 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4854
4855 init_random(1234567);
4856
4857 ThreadCritical::initialize();
4858
4859 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4860 if (Linux::page_size() == -1) {
4861 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4862 strerror(errno)));
4863 }
4864 init_page_sizes((size_t) Linux::page_size());
4865
4866 Linux::initialize_system_info();
4867
4868 // main_thread points to the aboriginal thread
4869 Linux::_main_thread = pthread_self();
4870
4871 Linux::clock_init();
4872 initial_time_count = os::elapsed_counter();
4873
4874 // pthread_condattr initialization for monotonic clock
4875 int status;
4876 pthread_condattr_t* _condattr = os::Linux::condAttr();
4877 if ((status = pthread_condattr_init(_condattr)) != 0) {
4878 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
4879 }
4880 // Only set the clock if CLOCK_MONOTONIC is available
4881 if (Linux::supports_monotonic_clock()) {
4882 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4883 if (status == EINVAL) {
4884 warning("Unable to use monotonic clock with relative timed-waits" \
4885 " - changes to the time-of-day clock may have adverse affects");
4886 } else {
4887 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
4888 }
4889 }
4890 }
4891 // else it defaults to CLOCK_REALTIME
4892
4893 pthread_mutex_init(&dl_mutex, NULL);
4894
4895 NOT_ZERO (
4896 // If the pagesize of the VM is greater than 8K determine the appropriate
4897 // number of initial guard pages. The user can change this with the
4898 // command line arguments, if needed.
4899 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
4900 StackYellowPages = 1;
4901 StackRedPages = 1;
4902 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
4903 }
4904 )
4905 }
4906
4907 // To install functions for atexit system call
4908 extern "C" {
4909 static void perfMemory_exit_helper() {
4910 perfMemory_exit();
4911 }
4912 }
4913
4914 // this is called _after_ the global arguments have been parsed
4915 jint os::init_2(void)
4916 {
4917 Linux::fast_thread_clock_init();
4918
4919 // Allocate a single page and mark it as readable for safepoint polling
4920 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4921 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4922
4923 os::set_polling_page( polling_page );
4924
4925 #ifndef PRODUCT
4926 if(Verbose && PrintMiscellaneous)
4927 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4928 #endif
4929
4930 if (!UseMembar) {
4931 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4932 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4933 os::set_memory_serialize_page( mem_serialize_page );
4934
4935 #ifndef PRODUCT
4936 if(Verbose && PrintMiscellaneous)
4937 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4938 #endif
4939 }
4940
4941 os::large_page_init();
4942
4943 // initialize suspend/resume support - must do this before signal_sets_init()
4944 if (SR_initialize() != 0) {
4945 perror("SR_initialize failed");
4946 return JNI_ERR;
4947 }
4948
4949 Linux::signal_sets_init();
4950 Linux::install_signal_handlers();
4951
4952 // Check minimum allowable stack size for thread creation and to initialize
4953 // the java system classes, including StackOverflowError - depends on page
4954 // size. Add a page for compiler2 recursion in main thread.
4955 // Add in 2*BytesPerWord times page size to account for VM stack during
4956 // class initialization depending on 32 or 64 bit VM.
4957 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4958 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
4959 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4960
4961 #ifdef ZERO
4962 // If this is Zero, allow at the very minimum one page each for the
4963 // Zero stack and the native stack. This won't make any difference
4964 // for 4k pages, but is significant for large pages.
4965 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4966 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+2) * Linux::page_size());
4967 #endif
4968
4969 size_t threadStackSizeInBytes = ThreadStackSize * K;
4970 if (threadStackSizeInBytes != 0 &&
4971 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4972 tty->print_cr("\nThe stack size specified is too small, "
4973 "Specify at least %dk",
4974 os::Linux::min_stack_allowed/ K);
4975 return JNI_ERR;
4976 }
4977
4978 // Make the stack size a multiple of the page size so that
4979 // the yellow/red zones can be guarded.
4980 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4981 vm_page_size()));
4982
4983 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4984
4985 #if defined(IA32) && !defined(ZERO)
4986 workaround_expand_exec_shield_cs_limit();
4987 #endif
4988
4989 Linux::libpthread_init();
4990 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4991 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4992 Linux::glibc_version(), Linux::libpthread_version(),
4993 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4994 }
4995
4996 if (UseNUMA) {
4997 if (!Linux::libnuma_init()) {
4998 UseNUMA = false;
4999 } else {
5000 if ((Linux::numa_max_node() < 1)) {
5001 // There's only one node(they start from 0), disable NUMA.
5002 UseNUMA = false;
5003 }
5004 }
5005 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5006 // we can make the adaptive lgrp chunk resizing work. If the user specified
5007 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
5008 // disable adaptive resizing.
5009 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5010 if (FLAG_IS_DEFAULT(UseNUMA)) {
5011 UseNUMA = false;
5012 } else {
5013 if (FLAG_IS_DEFAULT(UseLargePages) &&
5014 FLAG_IS_DEFAULT(UseSHM) &&
5015 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
5016 UseLargePages = false;
5017 } else {
5018 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
5019 UseAdaptiveSizePolicy = false;
5020 UseAdaptiveNUMAChunkSizing = false;
5021 }
5022 }
5023 }
5024 if (!UseNUMA && ForceNUMA) {
5025 UseNUMA = true;
5026 }
5027 }
5028
5029 if (MaxFDLimit) {
5030 // set the number of file descriptors to max. print out error
5031 // if getrlimit/setrlimit fails but continue regardless.
5032 struct rlimit nbr_files;
5033 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5034 if (status != 0) {
5035 if (PrintMiscellaneous && (Verbose || WizardMode))
5036 perror("os::init_2 getrlimit failed");
5037 } else {
5038 nbr_files.rlim_cur = nbr_files.rlim_max;
5039 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5040 if (status != 0) {
5041 if (PrintMiscellaneous && (Verbose || WizardMode))
5042 perror("os::init_2 setrlimit failed");
5043 }
5044 }
5045 }
5046
5047 // Initialize lock used to serialize thread creation (see os::create_thread)
5048 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
5049
5050 // at-exit methods are called in the reverse order of their registration.
5051 // atexit functions are called on return from main or as a result of a
5052 // call to exit(3C). There can be only 32 of these functions registered
5053 // and atexit() does not set errno.
5054
5055 if (PerfAllowAtExitRegistration) {
5056 // only register atexit functions if PerfAllowAtExitRegistration is set.
5057 // atexit functions can be delayed until process exit time, which
5058 // can be problematic for embedded VM situations. Embedded VMs should
5059 // call DestroyJavaVM() to assure that VM resources are released.
5060
5061 // note: perfMemory_exit_helper atexit function may be removed in
5062 // the future if the appropriate cleanup code can be added to the
5063 // VM_Exit VMOperation's doit method.
5064 if (atexit(perfMemory_exit_helper) != 0) {
5065 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5066 }
5067 }
5068
5069 // initialize thread priority policy
5070 prio_init();
5071
5072 return JNI_OK;
5073 }
5074
5075 // this is called at the end of vm_initialization
5076 void os::init_3(void) {
5077 #ifdef JAVASE_EMBEDDED
5078 // Start the MemNotifyThread
5079 if (LowMemoryProtection) {
5080 MemNotifyThread::start();
5081 }
5082 return;
5083 #endif
5084 }
5085
5086 // Mark the polling page as unreadable
5087 void os::make_polling_page_unreadable(void) {
5088 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
5089 fatal("Could not disable polling page");
5090 };
5091
5092 // Mark the polling page as readable
5093 void os::make_polling_page_readable(void) {
5094 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5095 fatal("Could not enable polling page");
5096 }
5097 };
5098
5099 int os::active_processor_count() {
5100 // Linux doesn't yet have a (official) notion of processor sets,
5101 // so just return the number of online processors.
5102 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
5103 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
5104 return online_cpus;
5105 }
5106
5107 void os::set_native_thread_name(const char *name) {
5108 // Not yet implemented.
5109 return;
5110 }
5111
5112 bool os::distribute_processes(uint length, uint* distribution) {
5113 // Not yet implemented.
5114 return false;
5115 }
5116
5117 bool os::bind_to_processor(uint processor_id) {
5118 // Not yet implemented.
5119 return false;
5120 }
5121
5122 ///
5123
5124 void os::SuspendedThreadTask::internal_do_task() {
5125 if (do_suspend(_thread->osthread())) {
5126 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5127 do_task(context);
5128 do_resume(_thread->osthread());
5129 }
5130 }
5131
5132 class PcFetcher : public os::SuspendedThreadTask {
5133 public:
5134 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5135 ExtendedPC result();
5136 protected:
5137 void do_task(const os::SuspendedThreadTaskContext& context);
5138 private:
5139 ExtendedPC _epc;
5140 };
5141
5142 ExtendedPC PcFetcher::result() {
5143 guarantee(is_done(), "task is not done yet.");
5144 return _epc;
5145 }
5146
5147 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5148 Thread* thread = context.thread();
5149 OSThread* osthread = thread->osthread();
5150 if (osthread->ucontext() != NULL) {
5151 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
5152 } else {
5153 // NULL context is unexpected, double-check this is the VMThread
5154 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5155 }
5156 }
5157
5158 // Suspends the target using the signal mechanism and then grabs the PC before
5159 // resuming the target. Used by the flat-profiler only
5160 ExtendedPC os::get_thread_pc(Thread* thread) {
5161 // Make sure that it is called by the watcher for the VMThread
5162 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5163 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5164
5165 PcFetcher fetcher(thread);
5166 fetcher.run();
5167 return fetcher.result();
5168 }
5169
5170 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
5171 {
5172 if (is_NPTL()) {
5173 return pthread_cond_timedwait(_cond, _mutex, _abstime);
5174 } else {
5175 #ifndef IA64
5176 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
5177 // word back to default 64bit precision if condvar is signaled. Java
5178 // wants 53bit precision. Save and restore current value.
5179 int fpu = get_fpu_control_word();
5180 #endif // IA64
5181 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
5182 #ifndef IA64
5183 set_fpu_control_word(fpu);
5184 #endif // IA64
5185 return status;
5186 }
5187 }
5188
5189 ////////////////////////////////////////////////////////////////////////////////
5190 // debug support
5191
5192 static address same_page(address x, address y) {
5193 intptr_t page_bits = -os::vm_page_size();
5194 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
5195 return x;
5196 else if (x > y)
5197 return (address)(intptr_t(y) | ~page_bits) + 1;
5198 else
5199 return (address)(intptr_t(y) & page_bits);
5200 }
5201
5202 bool os::find(address addr, outputStream* st) {
5203 Dl_info dlinfo;
5204 memset(&dlinfo, 0, sizeof(dlinfo));
5205 if (dladdr(addr, &dlinfo) != 0) {
5206 st->print(PTR_FORMAT ": ", addr);
5207 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5208 st->print("%s+%#x", dlinfo.dli_sname,
5209 addr - (intptr_t)dlinfo.dli_saddr);
5210 } else if (dlinfo.dli_fbase != NULL) {
5211 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
5212 } else {
5213 st->print("<absolute address>");
5214 }
5215 if (dlinfo.dli_fname != NULL) {
5216 st->print(" in %s", dlinfo.dli_fname);
5217 }
5218 if (dlinfo.dli_fbase != NULL) {
5219 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
5220 }
5221 st->cr();
5222
5223 if (Verbose) {
5224 // decode some bytes around the PC
5225 address begin = same_page(addr-40, addr);
5226 address end = same_page(addr+40, addr);
5227 address lowest = (address) dlinfo.dli_sname;
5228 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5229 if (begin < lowest) begin = lowest;
5230 Dl_info dlinfo2;
5231 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5232 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
5233 end = (address) dlinfo2.dli_saddr;
5234 Disassembler::decode(begin, end, st);
5235 }
5236 return true;
5237 }
5238 return false;
5239 }
5240
5241 ////////////////////////////////////////////////////////////////////////////////
5242 // misc
5243
5244 // This does not do anything on Linux. This is basically a hook for being
5245 // able to use structured exception handling (thread-local exception filters)
5246 // on, e.g., Win32.
5247 void
5248 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
5249 JavaCallArguments* args, Thread* thread) {
5250 f(value, method, args, thread);
5251 }
5252
5253 void os::print_statistics() {
5254 }
5255
5256 int os::message_box(const char* title, const char* message) {
5257 int i;
5258 fdStream err(defaultStream::error_fd());
5259 for (i = 0; i < 78; i++) err.print_raw("=");
5260 err.cr();
5261 err.print_raw_cr(title);
5262 for (i = 0; i < 78; i++) err.print_raw("-");
5263 err.cr();
5264 err.print_raw_cr(message);
5265 for (i = 0; i < 78; i++) err.print_raw("=");
5266 err.cr();
5267
5268 char buf[16];
5269 // Prevent process from exiting upon "read error" without consuming all CPU
5270 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5271
5272 return buf[0] == 'y' || buf[0] == 'Y';
5273 }
5274
5275 int os::stat(const char *path, struct stat *sbuf) {
5276 char pathbuf[MAX_PATH];
5277 if (strlen(path) > MAX_PATH - 1) {
5278 errno = ENAMETOOLONG;
5279 return -1;
5280 }
5281 os::native_path(strcpy(pathbuf, path));
5282 return ::stat(pathbuf, sbuf);
5283 }
5284
5285 bool os::check_heap(bool force) {
5286 return true;
5287 }
5288
5289 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5290 return ::vsnprintf(buf, count, format, args);
5291 }
5292
5293 // Is a (classpath) directory empty?
5294 bool os::dir_is_empty(const char* path) {
5295 DIR *dir = NULL;
5296 struct dirent *ptr;
5297
5298 dir = opendir(path);
5299 if (dir == NULL) return true;
5300
5301 /* Scan the directory */
5302 bool result = true;
5303 char buf[sizeof(struct dirent) + MAX_PATH];
5304 while (result && (ptr = ::readdir(dir)) != NULL) {
5305 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5306 result = false;
5307 }
5308 }
5309 closedir(dir);
5310 return result;
5311 }
5312
5313 // This code originates from JDK's sysOpen and open64_w
5314 // from src/solaris/hpi/src/system_md.c
5315
5316 #ifndef O_DELETE
5317 #define O_DELETE 0x10000
5318 #endif
5319
5320 // Open a file. Unlink the file immediately after open returns
5321 // if the specified oflag has the O_DELETE flag set.
5322 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5323
5324 int os::open(const char *path, int oflag, int mode) {
5325
5326 if (strlen(path) > MAX_PATH - 1) {
5327 errno = ENAMETOOLONG;
5328 return -1;
5329 }
5330 int fd;
5331 int o_delete = (oflag & O_DELETE);
5332 oflag = oflag & ~O_DELETE;
5333
5334 fd = ::open64(path, oflag, mode);
5335 if (fd == -1) return -1;
5336
5337 //If the open succeeded, the file might still be a directory
5338 {
5339 struct stat64 buf64;
5340 int ret = ::fstat64(fd, &buf64);
5341 int st_mode = buf64.st_mode;
5342
5343 if (ret != -1) {
5344 if ((st_mode & S_IFMT) == S_IFDIR) {
5345 errno = EISDIR;
5346 ::close(fd);
5347 return -1;
5348 }
5349 } else {
5350 ::close(fd);
5351 return -1;
5352 }
5353 }
5354
5355 /*
5356 * All file descriptors that are opened in the JVM and not
5357 * specifically destined for a subprocess should have the
5358 * close-on-exec flag set. If we don't set it, then careless 3rd
5359 * party native code might fork and exec without closing all
5360 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5361 * UNIXProcess.c), and this in turn might:
5362 *
5363 * - cause end-of-file to fail to be detected on some file
5364 * descriptors, resulting in mysterious hangs, or
5365 *
5366 * - might cause an fopen in the subprocess to fail on a system
5367 * suffering from bug 1085341.
5368 *
5369 * (Yes, the default setting of the close-on-exec flag is a Unix
5370 * design flaw)
5371 *
5372 * See:
5373 * 1085341: 32-bit stdio routines should support file descriptors >255
5374 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5375 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5376 */
5377 #ifdef FD_CLOEXEC
5378 {
5379 int flags = ::fcntl(fd, F_GETFD);
5380 if (flags != -1)
5381 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5382 }
5383 #endif
5384
5385 if (o_delete != 0) {
5386 ::unlink(path);
5387 }
5388 return fd;
5389 }
5390
5391
5392 // create binary file, rewriting existing file if required
5393 int os::create_binary_file(const char* path, bool rewrite_existing) {
5394 int oflags = O_WRONLY | O_CREAT;
5395 if (!rewrite_existing) {
5396 oflags |= O_EXCL;
5397 }
5398 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5399 }
5400
5401 // return current position of file pointer
5402 jlong os::current_file_offset(int fd) {
5403 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5404 }
5405
5406 // move file pointer to the specified offset
5407 jlong os::seek_to_file_offset(int fd, jlong offset) {
5408 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5409 }
5410
5411 // This code originates from JDK's sysAvailable
5412 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5413
5414 int os::available(int fd, jlong *bytes) {
5415 jlong cur, end;
5416 int mode;
5417 struct stat64 buf64;
5418
5419 if (::fstat64(fd, &buf64) >= 0) {
5420 mode = buf64.st_mode;
5421 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5422 /*
5423 * XXX: is the following call interruptible? If so, this might
5424 * need to go through the INTERRUPT_IO() wrapper as for other
5425 * blocking, interruptible calls in this file.
5426 */
5427 int n;
5428 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5429 *bytes = n;
5430 return 1;
5431 }
5432 }
5433 }
5434 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5435 return 0;
5436 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5437 return 0;
5438 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5439 return 0;
5440 }
5441 *bytes = end - cur;
5442 return 1;
5443 }
5444
5445 int os::socket_available(int fd, jint *pbytes) {
5446 // Linux doc says EINTR not returned, unlike Solaris
5447 int ret = ::ioctl(fd, FIONREAD, pbytes);
5448
5449 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5450 // is expected to return 0 on failure and 1 on success to the jdk.
5451 return (ret < 0) ? 0 : 1;
5452 }
5453
5454 // Map a block of memory.
5455 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5456 char *addr, size_t bytes, bool read_only,
5457 bool allow_exec) {
5458 int prot;
5459 int flags = MAP_PRIVATE;
5460
5461 if (read_only) {
5462 prot = PROT_READ;
5463 } else {
5464 prot = PROT_READ | PROT_WRITE;
5465 }
5466
5467 if (allow_exec) {
5468 prot |= PROT_EXEC;
5469 }
5470
5471 if (addr != NULL) {
5472 flags |= MAP_FIXED;
5473 }
5474
5475 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5476 fd, file_offset);
5477 if (mapped_address == MAP_FAILED) {
5478 return NULL;
5479 }
5480 return mapped_address;
5481 }
5482
5483
5484 // Remap a block of memory.
5485 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5486 char *addr, size_t bytes, bool read_only,
5487 bool allow_exec) {
5488 // same as map_memory() on this OS
5489 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5490 allow_exec);
5491 }
5492
5493
5494 // Unmap a block of memory.
5495 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5496 return munmap(addr, bytes) == 0;
5497 }
5498
5499 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5500
5501 static clockid_t thread_cpu_clockid(Thread* thread) {
5502 pthread_t tid = thread->osthread()->pthread_id();
5503 clockid_t clockid;
5504
5505 // Get thread clockid
5506 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5507 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5508 return clockid;
5509 }
5510
5511 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5512 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5513 // of a thread.
5514 //
5515 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5516 // the fast estimate available on the platform.
5517
5518 jlong os::current_thread_cpu_time() {
5519 if (os::Linux::supports_fast_thread_cpu_time()) {
5520 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5521 } else {
5522 // return user + sys since the cost is the same
5523 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5524 }
5525 }
5526
5527 jlong os::thread_cpu_time(Thread* thread) {
5528 // consistent with what current_thread_cpu_time() returns
5529 if (os::Linux::supports_fast_thread_cpu_time()) {
5530 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5531 } else {
5532 return slow_thread_cpu_time(thread, true /* user + sys */);
5533 }
5534 }
5535
5536 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5537 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5538 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5539 } else {
5540 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5541 }
5542 }
5543
5544 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5545 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5546 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5547 } else {
5548 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5549 }
5550 }
5551
5552 //
5553 // -1 on error.
5554 //
5555
5556 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5557 static bool proc_pid_cpu_avail = true;
5558 static bool proc_task_unchecked = true;
5559 static const char *proc_stat_path = "/proc/%d/stat";
5560 pid_t tid = thread->osthread()->thread_id();
5561 int i;
5562 char *s;
5563 char stat[2048];
5564 int statlen;
5565 char proc_name[64];
5566 int count;
5567 long sys_time, user_time;
5568 char string[64];
5569 char cdummy;
5570 int idummy;
5571 long ldummy;
5572 FILE *fp;
5573
5574 // We first try accessing /proc/<pid>/cpu since this is faster to
5575 // process. If this file is not present (linux kernels 2.5 and above)
5576 // then we open /proc/<pid>/stat.
5577 if ( proc_pid_cpu_avail ) {
5578 sprintf(proc_name, "/proc/%d/cpu", tid);
5579 fp = fopen(proc_name, "r");
5580 if ( fp != NULL ) {
5581 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
5582 fclose(fp);
5583 if ( count != 3 ) return -1;
5584
5585 if (user_sys_cpu_time) {
5586 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5587 } else {
5588 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5589 }
5590 }
5591 else proc_pid_cpu_avail = false;
5592 }
5593
5594 // The /proc/<tid>/stat aggregates per-process usage on
5595 // new Linux kernels 2.6+ where NPTL is supported.
5596 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5597 // See bug 6328462.
5598 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
5599 // and possibly in some other cases, so we check its availability.
5600 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5601 // This is executed only once
5602 proc_task_unchecked = false;
5603 fp = fopen("/proc/self/task", "r");
5604 if (fp != NULL) {
5605 proc_stat_path = "/proc/self/task/%d/stat";
5606 fclose(fp);
5607 }
5608 }
5609
5610 sprintf(proc_name, proc_stat_path, tid);
5611 fp = fopen(proc_name, "r");
5612 if ( fp == NULL ) return -1;
5613 statlen = fread(stat, 1, 2047, fp);
5614 stat[statlen] = '\0';
5615 fclose(fp);
5616
5617 // Skip pid and the command string. Note that we could be dealing with
5618 // weird command names, e.g. user could decide to rename java launcher
5619 // to "java 1.4.2 :)", then the stat file would look like
5620 // 1234 (java 1.4.2 :)) R ... ...
5621 // We don't really need to know the command string, just find the last
5622 // occurrence of ")" and then start parsing from there. See bug 4726580.
5623 s = strrchr(stat, ')');
5624 i = 0;
5625 if (s == NULL ) return -1;
5626
5627 // Skip blank chars
5628 do s++; while (isspace(*s));
5629
5630 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5631 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5632 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5633 &user_time, &sys_time);
5634 if ( count != 13 ) return -1;
5635 if (user_sys_cpu_time) {
5636 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5637 } else {
5638 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5639 }
5640 }
5641
5642 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5643 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5644 info_ptr->may_skip_backward = false; // elapsed time not wall time
5645 info_ptr->may_skip_forward = false; // elapsed time not wall time
5646 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5647 }
5648
5649 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5650 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5651 info_ptr->may_skip_backward = false; // elapsed time not wall time
5652 info_ptr->may_skip_forward = false; // elapsed time not wall time
5653 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5654 }
5655
5656 bool os::is_thread_cpu_time_supported() {
5657 return true;
5658 }
5659
5660 // System loadavg support. Returns -1 if load average cannot be obtained.
5661 // Linux doesn't yet have a (official) notion of processor sets,
5662 // so just return the system wide load average.
5663 int os::loadavg(double loadavg[], int nelem) {
5664 return ::getloadavg(loadavg, nelem);
5665 }
5666
5667 void os::pause() {
5668 char filename[MAX_PATH];
5669 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5670 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5671 } else {
5672 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5673 }
5674
5675 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5676 if (fd != -1) {
5677 struct stat buf;
5678 ::close(fd);
5679 while (::stat(filename, &buf) == 0) {
5680 (void)::poll(NULL, 0, 100);
5681 }
5682 } else {
5683 jio_fprintf(stderr,
5684 "Could not open pause file '%s', continuing immediately.\n", filename);
5685 }
5686 }
5687
5688
5689 // Refer to the comments in os_solaris.cpp park-unpark.
5690 //
5691 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5692 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5693 // For specifics regarding the bug see GLIBC BUGID 261237 :
5694 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5695 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5696 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5697 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5698 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5699 // and monitorenter when we're using 1-0 locking. All those operations may result in
5700 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5701 // of libpthread avoids the problem, but isn't practical.
5702 //
5703 // Possible remedies:
5704 //
5705 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5706 // This is palliative and probabilistic, however. If the thread is preempted
5707 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5708 // than the minimum period may have passed, and the abstime may be stale (in the
5709 // past) resultin in a hang. Using this technique reduces the odds of a hang
5710 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5711 //
5712 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5713 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5714 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5715 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5716 // thread.
5717 //
5718 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5719 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5720 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5721 // This also works well. In fact it avoids kernel-level scalability impediments
5722 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5723 // timers in a graceful fashion.
5724 //
5725 // 4. When the abstime value is in the past it appears that control returns
5726 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5727 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5728 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5729 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5730 // It may be possible to avoid reinitialization by checking the return
5731 // value from pthread_cond_timedwait(). In addition to reinitializing the
5732 // condvar we must establish the invariant that cond_signal() is only called
5733 // within critical sections protected by the adjunct mutex. This prevents
5734 // cond_signal() from "seeing" a condvar that's in the midst of being
5735 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5736 // desirable signal-after-unlock optimization that avoids futile context switching.
5737 //
5738 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5739 // structure when a condvar is used or initialized. cond_destroy() would
5740 // release the helper structure. Our reinitialize-after-timedwait fix
5741 // put excessive stress on malloc/free and locks protecting the c-heap.
5742 //
5743 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5744 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5745 // and only enabling the work-around for vulnerable environments.
5746
5747 // utility to compute the abstime argument to timedwait:
5748 // millis is the relative timeout time
5749 // abstime will be the absolute timeout time
5750 // TODO: replace compute_abstime() with unpackTime()
5751
5752 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5753 if (millis < 0) millis = 0;
5754
5755 jlong seconds = millis / 1000;
5756 millis %= 1000;
5757 if (seconds > 50000000) { // see man cond_timedwait(3T)
5758 seconds = 50000000;
5759 }
5760
5761 if (os::Linux::supports_monotonic_clock()) {
5762 struct timespec now;
5763 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5764 assert_status(status == 0, status, "clock_gettime");
5765 abstime->tv_sec = now.tv_sec + seconds;
5766 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5767 if (nanos >= NANOSECS_PER_SEC) {
5768 abstime->tv_sec += 1;
5769 nanos -= NANOSECS_PER_SEC;
5770 }
5771 abstime->tv_nsec = nanos;
5772 } else {
5773 struct timeval now;
5774 int status = gettimeofday(&now, NULL);
5775 assert(status == 0, "gettimeofday");
5776 abstime->tv_sec = now.tv_sec + seconds;
5777 long usec = now.tv_usec + millis * 1000;
5778 if (usec >= 1000000) {
5779 abstime->tv_sec += 1;
5780 usec -= 1000000;
5781 }
5782 abstime->tv_nsec = usec * 1000;
5783 }
5784 return abstime;
5785 }
5786
5787
5788 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
5789 // Conceptually TryPark() should be equivalent to park(0).
5790
5791 int os::PlatformEvent::TryPark() {
5792 for (;;) {
5793 const int v = _Event ;
5794 guarantee ((v == 0) || (v == 1), "invariant") ;
5795 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
5796 }
5797 }
5798
5799 void os::PlatformEvent::park() { // AKA "down()"
5800 // Invariant: Only the thread associated with the Event/PlatformEvent
5801 // may call park().
5802 // TODO: assert that _Assoc != NULL or _Assoc == Self
5803 int v ;
5804 for (;;) {
5805 v = _Event ;
5806 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5807 }
5808 guarantee (v >= 0, "invariant") ;
5809 if (v == 0) {
5810 // Do this the hard way by blocking ...
5811 int status = pthread_mutex_lock(_mutex);
5812 assert_status(status == 0, status, "mutex_lock");
5813 guarantee (_nParked == 0, "invariant") ;
5814 ++ _nParked ;
5815 while (_Event < 0) {
5816 status = pthread_cond_wait(_cond, _mutex);
5817 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5818 // Treat this the same as if the wait was interrupted
5819 if (status == ETIME) { status = EINTR; }
5820 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5821 }
5822 -- _nParked ;
5823
5824 _Event = 0 ;
5825 status = pthread_mutex_unlock(_mutex);
5826 assert_status(status == 0, status, "mutex_unlock");
5827 // Paranoia to ensure our locked and lock-free paths interact
5828 // correctly with each other.
5829 OrderAccess::fence();
5830 }
5831 guarantee (_Event >= 0, "invariant") ;
5832 }
5833
5834 int os::PlatformEvent::park(jlong millis) {
5835 guarantee (_nParked == 0, "invariant") ;
5836
5837 int v ;
5838 for (;;) {
5839 v = _Event ;
5840 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5841 }
5842 guarantee (v >= 0, "invariant") ;
5843 if (v != 0) return OS_OK ;
5844
5845 // We do this the hard way, by blocking the thread.
5846 // Consider enforcing a minimum timeout value.
5847 struct timespec abst;
5848 compute_abstime(&abst, millis);
5849
5850 int ret = OS_TIMEOUT;
5851 int status = pthread_mutex_lock(_mutex);
5852 assert_status(status == 0, status, "mutex_lock");
5853 guarantee (_nParked == 0, "invariant") ;
5854 ++_nParked ;
5855
5856 // Object.wait(timo) will return because of
5857 // (a) notification
5858 // (b) timeout
5859 // (c) thread.interrupt
5860 //
5861 // Thread.interrupt and object.notify{All} both call Event::set.
5862 // That is, we treat thread.interrupt as a special case of notification.
5863 // The underlying Solaris implementation, cond_timedwait, admits
5864 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5865 // JVM from making those visible to Java code. As such, we must
5866 // filter out spurious wakeups. We assume all ETIME returns are valid.
5867 //
5868 // TODO: properly differentiate simultaneous notify+interrupt.
5869 // In that case, we should propagate the notify to another waiter.
5870
5871 while (_Event < 0) {
5872 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5873 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5874 pthread_cond_destroy (_cond);
5875 pthread_cond_init (_cond, os::Linux::condAttr()) ;
5876 }
5877 assert_status(status == 0 || status == EINTR ||
5878 status == ETIME || status == ETIMEDOUT,
5879 status, "cond_timedwait");
5880 if (!FilterSpuriousWakeups) break ; // previous semantics
5881 if (status == ETIME || status == ETIMEDOUT) break ;
5882 // We consume and ignore EINTR and spurious wakeups.
5883 }
5884 --_nParked ;
5885 if (_Event >= 0) {
5886 ret = OS_OK;
5887 }
5888 _Event = 0 ;
5889 status = pthread_mutex_unlock(_mutex);
5890 assert_status(status == 0, status, "mutex_unlock");
5891 assert (_nParked == 0, "invariant") ;
5892 // Paranoia to ensure our locked and lock-free paths interact
5893 // correctly with each other.
5894 OrderAccess::fence();
5895 return ret;
5896 }
5897
5898 void os::PlatformEvent::unpark() {
5899 // Transitions for _Event:
5900 // 0 :=> 1
5901 // 1 :=> 1
5902 // -1 :=> either 0 or 1; must signal target thread
5903 // That is, we can safely transition _Event from -1 to either
5904 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
5905 // unpark() calls.
5906 // See also: "Semaphores in Plan 9" by Mullender & Cox
5907 //
5908 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5909 // that it will take two back-to-back park() calls for the owning
5910 // thread to block. This has the benefit of forcing a spurious return
5911 // from the first park() call after an unpark() call which will help
5912 // shake out uses of park() and unpark() without condition variables.
5913
5914 if (Atomic::xchg(1, &_Event) >= 0) return;
5915
5916 // Wait for the thread associated with the event to vacate
5917 int status = pthread_mutex_lock(_mutex);
5918 assert_status(status == 0, status, "mutex_lock");
5919 int AnyWaiters = _nParked;
5920 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5921 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5922 AnyWaiters = 0;
5923 pthread_cond_signal(_cond);
5924 }
5925 status = pthread_mutex_unlock(_mutex);
5926 assert_status(status == 0, status, "mutex_unlock");
5927 if (AnyWaiters != 0) {
5928 status = pthread_cond_signal(_cond);
5929 assert_status(status == 0, status, "cond_signal");
5930 }
5931
5932 // Note that we signal() _after dropping the lock for "immortal" Events.
5933 // This is safe and avoids a common class of futile wakeups. In rare
5934 // circumstances this can cause a thread to return prematurely from
5935 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5936 // simply re-test the condition and re-park itself.
5937 }
5938
5939
5940 // JSR166
5941 // -------------------------------------------------------
5942
5943 /*
5944 * The solaris and linux implementations of park/unpark are fairly
5945 * conservative for now, but can be improved. They currently use a
5946 * mutex/condvar pair, plus a a count.
5947 * Park decrements count if > 0, else does a condvar wait. Unpark
5948 * sets count to 1 and signals condvar. Only one thread ever waits
5949 * on the condvar. Contention seen when trying to park implies that someone
5950 * is unparking you, so don't wait. And spurious returns are fine, so there
5951 * is no need to track notifications.
5952 */
5953
5954 /*
5955 * This code is common to linux and solaris and will be moved to a
5956 * common place in dolphin.
5957 *
5958 * The passed in time value is either a relative time in nanoseconds
5959 * or an absolute time in milliseconds. Either way it has to be unpacked
5960 * into suitable seconds and nanoseconds components and stored in the
5961 * given timespec structure.
5962 * Given time is a 64-bit value and the time_t used in the timespec is only
5963 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5964 * overflow if times way in the future are given. Further on Solaris versions
5965 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5966 * number of seconds, in abstime, is less than current_time + 100,000,000.
5967 * As it will be 28 years before "now + 100000000" will overflow we can
5968 * ignore overflow and just impose a hard-limit on seconds using the value
5969 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5970 * years from "now".
5971 */
5972
5973 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5974 assert (time > 0, "convertTime");
5975 time_t max_secs = 0;
5976
5977 if (!os::Linux::supports_monotonic_clock() || isAbsolute) {
5978 struct timeval now;
5979 int status = gettimeofday(&now, NULL);
5980 assert(status == 0, "gettimeofday");
5981
5982 max_secs = now.tv_sec + MAX_SECS;
5983
5984 if (isAbsolute) {
5985 jlong secs = time / 1000;
5986 if (secs > max_secs) {
5987 absTime->tv_sec = max_secs;
5988 } else {
5989 absTime->tv_sec = secs;
5990 }
5991 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5992 } else {
5993 jlong secs = time / NANOSECS_PER_SEC;
5994 if (secs >= MAX_SECS) {
5995 absTime->tv_sec = max_secs;
5996 absTime->tv_nsec = 0;
5997 } else {
5998 absTime->tv_sec = now.tv_sec + secs;
5999 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
6000 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6001 absTime->tv_nsec -= NANOSECS_PER_SEC;
6002 ++absTime->tv_sec; // note: this must be <= max_secs
6003 }
6004 }
6005 }
6006 } else {
6007 // must be relative using monotonic clock
6008 struct timespec now;
6009 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
6010 assert_status(status == 0, status, "clock_gettime");
6011 max_secs = now.tv_sec + MAX_SECS;
6012 jlong secs = time / NANOSECS_PER_SEC;
6013 if (secs >= MAX_SECS) {
6014 absTime->tv_sec = max_secs;
6015 absTime->tv_nsec = 0;
6016 } else {
6017 absTime->tv_sec = now.tv_sec + secs;
6018 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
6019 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6020 absTime->tv_nsec -= NANOSECS_PER_SEC;
6021 ++absTime->tv_sec; // note: this must be <= max_secs
6022 }
6023 }
6024 }
6025 assert(absTime->tv_sec >= 0, "tv_sec < 0");
6026 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
6027 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
6028 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
6029 }
6030
6031 void Parker::park(bool isAbsolute, jlong time) {
6032 // Ideally we'd do something useful while spinning, such
6033 // as calling unpackTime().
6034
6035 // Optional fast-path check:
6036 // Return immediately if a permit is available.
6037 // We depend on Atomic::xchg() having full barrier semantics
6038 // since we are doing a lock-free update to _counter.
6039 if (Atomic::xchg(0, &_counter) > 0) return;
6040
6041 Thread* thread = Thread::current();
6042 assert(thread->is_Java_thread(), "Must be JavaThread");
6043 JavaThread *jt = (JavaThread *)thread;
6044
6045 // Optional optimization -- avoid state transitions if there's an interrupt pending.
6046 // Check interrupt before trying to wait
6047 if (Thread::is_interrupted(thread, false)) {
6048 return;
6049 }
6050
6051 // Next, demultiplex/decode time arguments
6052 timespec absTime;
6053 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
6054 return;
6055 }
6056 if (time > 0) {
6057 unpackTime(&absTime, isAbsolute, time);
6058 }
6059
6060
6061 // Enter safepoint region
6062 // Beware of deadlocks such as 6317397.
6063 // The per-thread Parker:: mutex is a classic leaf-lock.
6064 // In particular a thread must never block on the Threads_lock while
6065 // holding the Parker:: mutex. If safepoints are pending both the
6066 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
6067 ThreadBlockInVM tbivm(jt);
6068
6069 // Don't wait if cannot get lock since interference arises from
6070 // unblocking. Also. check interrupt before trying wait
6071 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
6072 return;
6073 }
6074
6075 int status ;
6076 if (_counter > 0) { // no wait needed
6077 _counter = 0;
6078 status = pthread_mutex_unlock(_mutex);
6079 assert (status == 0, "invariant") ;
6080 // Paranoia to ensure our locked and lock-free paths interact
6081 // correctly with each other and Java-level accesses.
6082 OrderAccess::fence();
6083 return;
6084 }
6085
6086 #ifdef ASSERT
6087 // Don't catch signals while blocked; let the running threads have the signals.
6088 // (This allows a debugger to break into the running thread.)
6089 sigset_t oldsigs;
6090 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
6091 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
6092 #endif
6093
6094 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
6095 jt->set_suspend_equivalent();
6096 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
6097 assert(_cur_index == -1, "invariant");
6098 if (time == 0) {
6099 _cur_index = REL_INDEX; // arbitrary choice when not timed
6100 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
6101 } else {
6102 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
6103 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
6104 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
6105 pthread_cond_destroy (&_cond[_cur_index]) ;
6106 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
6107 }
6108 }
6109 _cur_index = -1;
6110
6111 assert_status(status == 0 || status == EINTR ||
6112 status == ETIME || status == ETIMEDOUT,
6113 status, "cond_timedwait");
6114
6115 #ifdef ASSERT
6116 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
6117 #endif
6118
6119 _counter = 0 ;
6120 status = pthread_mutex_unlock(_mutex) ;
6121 assert_status(status == 0, status, "invariant") ;
6122 // Paranoia to ensure our locked and lock-free paths interact
6123 // correctly with each other and Java-level accesses.
6124 OrderAccess::fence();
6125
6126 // If externally suspended while waiting, re-suspend
6127 if (jt->handle_special_suspend_equivalent_condition()) {
6128 jt->java_suspend_self();
6129 }
6130 }
6131
6132 void Parker::unpark() {
6133 int s, status ;
6134 status = pthread_mutex_lock(_mutex);
6135 assert (status == 0, "invariant") ;
6136 s = _counter;
6137 _counter = 1;
6138 if (s < 1) {
6139 // thread might be parked
6140 if (_cur_index != -1) {
6141 // thread is definitely parked
6142 if (WorkAroundNPTLTimedWaitHang) {
6143 status = pthread_cond_signal (&_cond[_cur_index]);
6144 assert (status == 0, "invariant");
6145 status = pthread_mutex_unlock(_mutex);
6146 assert (status == 0, "invariant");
6147 } else {
6148 status = pthread_mutex_unlock(_mutex);
6149 assert (status == 0, "invariant");
6150 status = pthread_cond_signal (&_cond[_cur_index]);
6151 assert (status == 0, "invariant");
6152 }
6153 } else {
6154 pthread_mutex_unlock(_mutex);
6155 assert (status == 0, "invariant") ;
6156 }
6157 } else {
6158 pthread_mutex_unlock(_mutex);
6159 assert (status == 0, "invariant") ;
6160 }
6161 }
6162
6163
6164 extern char** environ;
6165
6166 #ifndef __NR_fork
6167 #ifdef BUILTIN_SIM
6168 #define __NR_fork 57
6169 #else
6170 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57) AARCH64_ONLY(1079)
6171 #endif
6172 #endif
6173
6174 #ifndef __NR_execve
6175 #ifdef BUILTIN_SIM
6176 #define __NR_execve 59
6177 #else
6178 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59) AARCH64_ONLY(221)
6179 #endif
6180 #endif
6181
6182 // Run the specified command in a separate process. Return its exit value,
6183 // or -1 on failure (e.g. can't fork a new process).
6184 // Unlike system(), this function can be called from signal handler. It
6185 // doesn't block SIGINT et al.
6186 int os::fork_and_exec(char* cmd) {
6187 const char * argv[4] = {"sh", "-c", cmd, NULL};
6188
6189 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
6190 // pthread_atfork handlers and reset pthread library. All we need is a
6191 // separate process to execve. Make a direct syscall to fork process.
6192 // On IA64 there's no fork syscall, we have to use fork() and hope for
6193 // the best...
6194 pid_t pid = NOT_IA64(syscall(__NR_fork);)
6195 IA64_ONLY(fork();)
6196
6197 if (pid < 0) {
6198 // fork failed
6199 return -1;
6200
6201 } else if (pid == 0) {
6202 // child process
6203
6204 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
6205 // first to kill every thread on the thread list. Because this list is
6206 // not reset by fork() (see notes above), execve() will instead kill
6207 // every thread in the parent process. We know this is the only thread
6208 // in the new process, so make a system call directly.
6209 // IA64 should use normal execve() from glibc to match the glibc fork()
6210 // above.
6211 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
6212 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
6213
6214 // execve failed
6215 _exit(-1);
6216
6217 } else {
6218 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
6219 // care about the actual exit code, for now.
6220
6221 int status;
6222
6223 // Wait for the child process to exit. This returns immediately if
6224 // the child has already exited. */
6225 while (waitpid(pid, &status, 0) < 0) {
6226 switch (errno) {
6227 case ECHILD: return 0;
6228 case EINTR: break;
6229 default: return -1;
6230 }
6231 }
6232
6233 if (WIFEXITED(status)) {
6234 // The child exited normally; get its exit code.
6235 return WEXITSTATUS(status);
6236 } else if (WIFSIGNALED(status)) {
6237 // The child exited because of a signal
6238 // The best value to return is 0x80 + signal number,
6239 // because that is what all Unix shells do, and because
6240 // it allows callers to distinguish between process exit and
6241 // process death by signal.
6242 return 0x80 + WTERMSIG(status);
6243 } else {
6244 // Unknown exit code; pass it through
6245 return status;
6246 }
6247 }
6248 }
6249
6250 // is_headless_jre()
6251 //
6252 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
6253 // in order to report if we are running in a headless jre
6254 //
6255 // Since JDK8 xawt/libmawt.so was moved into the same directory
6256 // as libawt.so, and renamed libawt_xawt.so
6257 //
6258 bool os::is_headless_jre() {
6259 struct stat statbuf;
6260 char buf[MAXPATHLEN];
6261 char libmawtpath[MAXPATHLEN];
6262 const char *xawtstr = "/xawt/libmawt.so";
6263 const char *new_xawtstr = "/libawt_xawt.so";
6264 char *p;
6265
6266 // Get path to libjvm.so
6267 os::jvm_path(buf, sizeof(buf));
6268
6269 // Get rid of libjvm.so
6270 p = strrchr(buf, '/');
6271 if (p == NULL) return false;
6272 else *p = '\0';
6273
6274 // Get rid of client or server
6275 p = strrchr(buf, '/');
6276 if (p == NULL) return false;
6277 else *p = '\0';
6278
6279 // check xawt/libmawt.so
6280 strcpy(libmawtpath, buf);
6281 strcat(libmawtpath, xawtstr);
6282 if (::stat(libmawtpath, &statbuf) == 0) return false;
6283
6284 // check libawt_xawt.so
6285 strcpy(libmawtpath, buf);
6286 strcat(libmawtpath, new_xawtstr);
6287 if (::stat(libmawtpath, &statbuf) == 0) return false;
6288
6289 return true;
6290 }
6291
6292 // Get the default path to the core file
6293 // Returns the length of the string
6294 int os::get_core_path(char* buffer, size_t bufferSize) {
6295 const char* p = get_current_directory(buffer, bufferSize);
6296
6297 if (p == NULL) {
6298 assert(p != NULL, "failed to get current directory");
6299 return 0;
6300 }
6301
6302 return strlen(buffer);
6303 }
6304
6305 #ifdef JAVASE_EMBEDDED
6306 //
6307 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
6308 //
6309 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
6310
6311 // ctor
6312 //
6313 MemNotifyThread::MemNotifyThread(int fd): Thread() {
6314 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
6315 _fd = fd;
6316
6317 if (os::create_thread(this, os::os_thread)) {
6318 _memnotify_thread = this;
6319 os::set_priority(this, NearMaxPriority);
6320 os::start_thread(this);
6321 }
6322 }
6323
6324 // Where all the work gets done
6325 //
6326 void MemNotifyThread::run() {
6327 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
6328
6329 // Set up the select arguments
6330 fd_set rfds;
6331 if (_fd != -1) {
6332 FD_ZERO(&rfds);
6333 FD_SET(_fd, &rfds);
6334 }
6335
6336 // Now wait for the mem_notify device to wake up
6337 while (1) {
6338 // Wait for the mem_notify device to signal us..
6339 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
6340 if (rc == -1) {
6341 perror("select!\n");
6342 break;
6343 } else if (rc) {
6344 //ssize_t free_before = os::available_memory();
6345 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
6346
6347 // The kernel is telling us there is not much memory left...
6348 // try to do something about that
6349
6350 // If we are not already in a GC, try one.
6351 if (!Universe::heap()->is_gc_active()) {
6352 Universe::heap()->collect(GCCause::_allocation_failure);
6353
6354 //ssize_t free_after = os::available_memory();
6355 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
6356 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
6357 }
6358 // We might want to do something like the following if we find the GC's are not helping...
6359 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
6360 }
6361 }
6362 }
6363
6364 //
6365 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
6366 //
6367 void MemNotifyThread::start() {
6368 int fd;
6369 fd = open ("/dev/mem_notify", O_RDONLY, 0);
6370 if (fd < 0) {
6371 return;
6372 }
6373
6374 if (memnotify_thread() == NULL) {
6375 new MemNotifyThread(fd);
6376 }
6377 }
6378
6379 #endif // JAVASE_EMBEDDED
6380
6381
6382 /////////////// Unit tests ///////////////
6383
6384 #ifndef PRODUCT
6385
6386 #define test_log(...) \
6387 do {\
6388 if (VerboseInternalVMTests) { \
6389 tty->print_cr(__VA_ARGS__); \
6390 tty->flush(); \
6391 }\
6392 } while (false)
6393
6394 class TestReserveMemorySpecial : AllStatic {
6395 public:
6396 static void small_page_write(void* addr, size_t size) {
6397 size_t page_size = os::vm_page_size();
6398
6399 char* end = (char*)addr + size;
6400 for (char* p = (char*)addr; p < end; p += page_size) {
6401 *p = 1;
6402 }
6403 }
6404
6405 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6406 if (!UseHugeTLBFS) {
6407 return;
6408 }
6409
6410 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6411
6412 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6413
6414 if (addr != NULL) {
6415 small_page_write(addr, size);
6416
6417 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6418 }
6419 }
6420
6421 static void test_reserve_memory_special_huge_tlbfs_only() {
6422 if (!UseHugeTLBFS) {
6423 return;
6424 }
6425
6426 size_t lp = os::large_page_size();
6427
6428 for (size_t size = lp; size <= lp * 10; size += lp) {
6429 test_reserve_memory_special_huge_tlbfs_only(size);
6430 }
6431 }
6432
6433 static void test_reserve_memory_special_huge_tlbfs_mixed(size_t size, size_t alignment) {
6434 if (!UseHugeTLBFS) {
6435 return;
6436 }
6437
6438 test_log("test_reserve_memory_special_huge_tlbfs_mixed(" SIZE_FORMAT ", " SIZE_FORMAT ")",
6439 size, alignment);
6440
6441 assert(size >= os::large_page_size(), "Incorrect input to test");
6442
6443 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6444
6445 if (addr != NULL) {
6446 small_page_write(addr, size);
6447
6448 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6449 }
6450 }
6451
6452 static void test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(size_t size) {
6453 size_t lp = os::large_page_size();
6454 size_t ag = os::vm_allocation_granularity();
6455
6456 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6457 test_reserve_memory_special_huge_tlbfs_mixed(size, alignment);
6458 }
6459 }
6460
6461 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6462 size_t lp = os::large_page_size();
6463 size_t ag = os::vm_allocation_granularity();
6464
6465 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp);
6466 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + ag);
6467 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp + lp / 2);
6468 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2);
6469 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + ag);
6470 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 - ag);
6471 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 2 + lp / 2);
6472 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10);
6473 test_reserve_memory_special_huge_tlbfs_mixed_all_alignments(lp * 10 + lp / 2);
6474 }
6475
6476 static void test_reserve_memory_special_huge_tlbfs() {
6477 if (!UseHugeTLBFS) {
6478 return;
6479 }
6480
6481 test_reserve_memory_special_huge_tlbfs_only();
6482 test_reserve_memory_special_huge_tlbfs_mixed();
6483 }
6484
6485 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6486 if (!UseSHM) {
6487 return;
6488 }
6489
6490 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6491
6492 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6493
6494 if (addr != NULL) {
6495 assert(is_ptr_aligned(addr, alignment), "Check");
6496 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6497
6498 small_page_write(addr, size);
6499
6500 os::Linux::release_memory_special_shm(addr, size);
6501 }
6502 }
6503
6504 static void test_reserve_memory_special_shm() {
6505 size_t lp = os::large_page_size();
6506 size_t ag = os::vm_allocation_granularity();
6507
6508 for (size_t size = ag; size < lp * 3; size += ag) {
6509 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6510 test_reserve_memory_special_shm(size, alignment);
6511 }
6512 }
6513 }
6514
6515 static void test() {
6516 test_reserve_memory_special_huge_tlbfs();
6517 test_reserve_memory_special_shm();
6518 }
6519 };
6520
6521 void TestReserveMemorySpecial_test() {
6522 TestReserveMemorySpecial::test();
6523 }
6524
6525 #endif