1 /*
2 * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "logging/log.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "mutex_linux.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "os_linux.inline.hpp"
41 #include "os_share_linux.hpp"
42 #include "prims/jniFastGetField.hpp"
43 #include "prims/jvm.h"
44 #include "prims/jvm_misc.hpp"
45 #include "runtime/arguments.hpp"
46 #include "runtime/atomic.inline.hpp"
47 #include "runtime/extendedPC.hpp"
48 #include "runtime/globals.hpp"
49 #include "runtime/interfaceSupport.hpp"
50 #include "runtime/init.hpp"
51 #include "runtime/java.hpp"
52 #include "runtime/javaCalls.hpp"
53 #include "runtime/mutexLocker.hpp"
54 #include "runtime/objectMonitor.hpp"
55 #include "runtime/orderAccess.inline.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/perfMemory.hpp"
58 #include "runtime/sharedRuntime.hpp"
59 #include "runtime/statSampler.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/thread.inline.hpp"
62 #include "runtime/threadCritical.hpp"
63 #include "runtime/timer.hpp"
64 #include "semaphore_posix.hpp"
65 #include "services/attachListener.hpp"
66 #include "services/memTracker.hpp"
67 #include "services/runtimeService.hpp"
68 #include "utilities/decoder.hpp"
69 #include "utilities/defaultStream.hpp"
70 #include "utilities/events.hpp"
71 #include "utilities/elfFile.hpp"
72 #include "utilities/growableArray.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/vmError.hpp"
75
76 // put OS-includes here
77 # include <sys/types.h>
78 # include <sys/mman.h>
79 # include <sys/stat.h>
80 # include <sys/select.h>
81 # include <pthread.h>
82 # include <signal.h>
83 # include <errno.h>
84 # include <dlfcn.h>
85 # include <stdio.h>
86 # include <unistd.h>
87 # include <sys/resource.h>
88 # include <pthread.h>
89 # include <sys/stat.h>
90 # include <sys/time.h>
91 # include <sys/times.h>
92 # include <sys/utsname.h>
93 # include <sys/socket.h>
94 # include <sys/wait.h>
95 # include <pwd.h>
96 # include <poll.h>
97 # include <semaphore.h>
98 # include <fcntl.h>
99 # include <string.h>
100 # include <syscall.h>
101 # include <sys/sysinfo.h>
102 # include <gnu/libc-version.h>
103 # include <sys/ipc.h>
104 # include <sys/shm.h>
105 # include <link.h>
106 # include <stdint.h>
107 # include <inttypes.h>
108 # include <sys/ioctl.h>
109
110 #ifndef _GNU_SOURCE
111 #define _GNU_SOURCE
112 #include <sched.h>
113 #undef _GNU_SOURCE
114 #else
115 #include <sched.h>
116 #endif
117
118 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
119 // getrusage() is prepared to handle the associated failure.
120 #ifndef RUSAGE_THREAD
121 #define RUSAGE_THREAD (1) /* only the calling thread */
122 #endif
123
124 #define MAX_PATH (2 * K)
125
126 #define MAX_SECS 100000000
127
128 // for timer info max values which include all bits
129 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
130
131 #define LARGEPAGES_BIT (1 << 6)
132 ////////////////////////////////////////////////////////////////////////////////
133 // global variables
134 julong os::Linux::_physical_memory = 0;
135
136 address os::Linux::_initial_thread_stack_bottom = NULL;
137 uintptr_t os::Linux::_initial_thread_stack_size = 0;
138
139 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
140 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
141 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
142 Mutex* os::Linux::_createThread_lock = NULL;
143 pthread_t os::Linux::_main_thread;
144 int os::Linux::_page_size = -1;
145 const int os::Linux::_vm_default_page_size = (8 * K);
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
149 pthread_condattr_t os::Linux::_condattr[1];
150
151 static jlong initial_time_count=0;
152
153 static int clock_tics_per_sec = 100;
154
155 // For diagnostics to print a message once. see run_periodic_checks
156 static sigset_t check_signal_done;
157 static bool check_signals = true;
158
159 // Signal number used to suspend/resume a thread
160
161 // do not use any signal number less than SIGSEGV, see 4355769
162 static int SR_signum = SIGUSR2;
163 sigset_t SR_sigset;
164
165 // Declarations
166 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
167
168 // utility functions
169
170 static int SR_initialize();
171
172 julong os::available_memory() {
173 return Linux::available_memory();
174 }
175
176 julong os::Linux::available_memory() {
177 // values in struct sysinfo are "unsigned long"
178 struct sysinfo si;
179 sysinfo(&si);
180
181 return (julong)si.freeram * si.mem_unit;
182 }
183
184 julong os::physical_memory() {
185 return Linux::physical_memory();
186 }
187
188 // Return true if user is running as root.
189
190 bool os::have_special_privileges() {
191 static bool init = false;
192 static bool privileges = false;
193 if (!init) {
194 privileges = (getuid() != geteuid()) || (getgid() != getegid());
195 init = true;
196 }
197 return privileges;
198 }
199
200
201 #ifndef SYS_gettid
202 // i386: 224, ia64: 1105, amd64: 186, sparc 143
203 #ifdef __ia64__
204 #define SYS_gettid 1105
205 #else
206 #ifdef __i386__
207 #define SYS_gettid 224
208 #else
209 #ifdef __amd64__
210 #define SYS_gettid 186
211 #else
212 #ifdef __sparc__
213 #define SYS_gettid 143
214 #else
215 #error define gettid for the arch
216 #endif
217 #endif
218 #endif
219 #endif
220 #endif
221
222 // Cpu architecture string
223 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
224
225
226 // pid_t gettid()
227 //
228 // Returns the kernel thread id of the currently running thread. Kernel
229 // thread id is used to access /proc.
230 pid_t os::Linux::gettid() {
231 int rslt = syscall(SYS_gettid);
232 assert(rslt != -1, "must be."); // old linuxthreads implementation?
233 return (pid_t)rslt;
234 }
235
236 // Most versions of linux have a bug where the number of processors are
237 // determined by looking at the /proc file system. In a chroot environment,
238 // the system call returns 1. This causes the VM to act as if it is
239 // a single processor and elide locking (see is_MP() call).
240 static bool unsafe_chroot_detected = false;
241 static const char *unstable_chroot_error = "/proc file system not found.\n"
242 "Java may be unstable running multithreaded in a chroot "
243 "environment on Linux when /proc filesystem is not mounted.";
244
245 void os::Linux::initialize_system_info() {
246 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
247 if (processor_count() == 1) {
248 pid_t pid = os::Linux::gettid();
249 char fname[32];
250 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
251 FILE *fp = fopen(fname, "r");
252 if (fp == NULL) {
253 unsafe_chroot_detected = true;
254 } else {
255 fclose(fp);
256 }
257 }
258 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
259 assert(processor_count() > 0, "linux error");
260 }
261
262 void os::init_system_properties_values() {
263 // The next steps are taken in the product version:
264 //
265 // Obtain the JAVA_HOME value from the location of libjvm.so.
266 // This library should be located at:
267 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
268 //
269 // If "/jre/lib/" appears at the right place in the path, then we
270 // assume libjvm.so is installed in a JDK and we use this path.
271 //
272 // Otherwise exit with message: "Could not create the Java virtual machine."
273 //
274 // The following extra steps are taken in the debugging version:
275 //
276 // If "/jre/lib/" does NOT appear at the right place in the path
277 // instead of exit check for $JAVA_HOME environment variable.
278 //
279 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
280 // then we append a fake suffix "hotspot/libjvm.so" to this path so
281 // it looks like libjvm.so is installed there
282 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
283 //
284 // Otherwise exit.
285 //
286 // Important note: if the location of libjvm.so changes this
287 // code needs to be changed accordingly.
288
289 // See ld(1):
290 // The linker uses the following search paths to locate required
291 // shared libraries:
292 // 1: ...
293 // ...
294 // 7: The default directories, normally /lib and /usr/lib.
295 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
296 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
297 #else
298 #define DEFAULT_LIBPATH "/lib:/usr/lib"
299 #endif
300
301 // Base path of extensions installed on the system.
302 #define SYS_EXT_DIR "/usr/java/packages"
303 #define EXTENSIONS_DIR "/lib/ext"
304
305 // Buffer that fits several sprintfs.
306 // Note that the space for the colon and the trailing null are provided
307 // by the nulls included by the sizeof operator.
308 const size_t bufsize =
309 MAX2((size_t)MAXPATHLEN, // For dll_dir & friends.
310 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR)); // extensions dir
311 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
312
313 // sysclasspath, java_home, dll_dir
314 {
315 char *pslash;
316 os::jvm_path(buf, bufsize);
317
318 // Found the full path to libjvm.so.
319 // Now cut the path to <java_home>/jre if we can.
320 pslash = strrchr(buf, '/');
321 if (pslash != NULL) {
322 *pslash = '\0'; // Get rid of /libjvm.so.
323 }
324 pslash = strrchr(buf, '/');
325 if (pslash != NULL) {
326 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
327 }
328 Arguments::set_dll_dir(buf);
329
330 if (pslash != NULL) {
331 pslash = strrchr(buf, '/');
332 if (pslash != NULL) {
333 *pslash = '\0'; // Get rid of /<arch>.
334 pslash = strrchr(buf, '/');
335 if (pslash != NULL) {
336 *pslash = '\0'; // Get rid of /lib.
337 }
338 }
339 }
340 Arguments::set_java_home(buf);
341 set_boot_path('/', ':');
342 }
343
344 // Where to look for native libraries.
345 //
346 // Note: Due to a legacy implementation, most of the library path
347 // is set in the launcher. This was to accomodate linking restrictions
348 // on legacy Linux implementations (which are no longer supported).
349 // Eventually, all the library path setting will be done here.
350 //
351 // However, to prevent the proliferation of improperly built native
352 // libraries, the new path component /usr/java/packages is added here.
353 // Eventually, all the library path setting will be done here.
354 {
355 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
356 // should always exist (until the legacy problem cited above is
357 // addressed).
358 const char *v = ::getenv("LD_LIBRARY_PATH");
359 const char *v_colon = ":";
360 if (v == NULL) { v = ""; v_colon = ""; }
361 // That's +1 for the colon and +1 for the trailing '\0'.
362 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
363 strlen(v) + 1 +
364 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
365 mtInternal);
366 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
367 Arguments::set_library_path(ld_library_path);
368 FREE_C_HEAP_ARRAY(char, ld_library_path);
369 }
370
371 // Extensions directories.
372 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
373 Arguments::set_ext_dirs(buf);
374
375 FREE_C_HEAP_ARRAY(char, buf);
376
377 #undef DEFAULT_LIBPATH
378 #undef SYS_EXT_DIR
379 #undef EXTENSIONS_DIR
380 }
381
382 ////////////////////////////////////////////////////////////////////////////////
383 // breakpoint support
384
385 void os::breakpoint() {
386 BREAKPOINT;
387 }
388
389 extern "C" void breakpoint() {
390 // use debugger to set breakpoint here
391 }
392
393 ////////////////////////////////////////////////////////////////////////////////
394 // signal support
395
396 debug_only(static bool signal_sets_initialized = false);
397 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
398
399 bool os::Linux::is_sig_ignored(int sig) {
400 struct sigaction oact;
401 sigaction(sig, (struct sigaction*)NULL, &oact);
402 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
403 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
404 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
405 return true;
406 } else {
407 return false;
408 }
409 }
410
411 void os::Linux::signal_sets_init() {
412 // Should also have an assertion stating we are still single-threaded.
413 assert(!signal_sets_initialized, "Already initialized");
414 // Fill in signals that are necessarily unblocked for all threads in
415 // the VM. Currently, we unblock the following signals:
416 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
417 // by -Xrs (=ReduceSignalUsage));
418 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
419 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
420 // the dispositions or masks wrt these signals.
421 // Programs embedding the VM that want to use the above signals for their
422 // own purposes must, at this time, use the "-Xrs" option to prevent
423 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
424 // (See bug 4345157, and other related bugs).
425 // In reality, though, unblocking these signals is really a nop, since
426 // these signals are not blocked by default.
427 sigemptyset(&unblocked_sigs);
428 sigemptyset(&allowdebug_blocked_sigs);
429 sigaddset(&unblocked_sigs, SIGILL);
430 sigaddset(&unblocked_sigs, SIGSEGV);
431 sigaddset(&unblocked_sigs, SIGBUS);
432 sigaddset(&unblocked_sigs, SIGFPE);
433 #if defined(PPC64)
434 sigaddset(&unblocked_sigs, SIGTRAP);
435 #endif
436 sigaddset(&unblocked_sigs, SR_signum);
437
438 if (!ReduceSignalUsage) {
439 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
440 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
441 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
442 }
443 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
444 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
445 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
446 }
447 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
448 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
449 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
450 }
451 }
452 // Fill in signals that are blocked by all but the VM thread.
453 sigemptyset(&vm_sigs);
454 if (!ReduceSignalUsage) {
455 sigaddset(&vm_sigs, BREAK_SIGNAL);
456 }
457 debug_only(signal_sets_initialized = true);
458
459 }
460
461 // These are signals that are unblocked while a thread is running Java.
462 // (For some reason, they get blocked by default.)
463 sigset_t* os::Linux::unblocked_signals() {
464 assert(signal_sets_initialized, "Not initialized");
465 return &unblocked_sigs;
466 }
467
468 // These are the signals that are blocked while a (non-VM) thread is
469 // running Java. Only the VM thread handles these signals.
470 sigset_t* os::Linux::vm_signals() {
471 assert(signal_sets_initialized, "Not initialized");
472 return &vm_sigs;
473 }
474
475 // These are signals that are blocked during cond_wait to allow debugger in
476 sigset_t* os::Linux::allowdebug_blocked_signals() {
477 assert(signal_sets_initialized, "Not initialized");
478 return &allowdebug_blocked_sigs;
479 }
480
481 void os::Linux::hotspot_sigmask(Thread* thread) {
482
483 //Save caller's signal mask before setting VM signal mask
484 sigset_t caller_sigmask;
485 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
486
487 OSThread* osthread = thread->osthread();
488 osthread->set_caller_sigmask(caller_sigmask);
489
490 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
491
492 if (!ReduceSignalUsage) {
493 if (thread->is_VM_thread()) {
494 // Only the VM thread handles BREAK_SIGNAL ...
495 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
496 } else {
497 // ... all other threads block BREAK_SIGNAL
498 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
499 }
500 }
501 }
502
503 //////////////////////////////////////////////////////////////////////////////
504 // detecting pthread library
505
506 void os::Linux::libpthread_init() {
507 // Save glibc and pthread version strings.
508 #if !defined(_CS_GNU_LIBC_VERSION) || \
509 !defined(_CS_GNU_LIBPTHREAD_VERSION)
510 #error "glibc too old (< 2.3.2)"
511 #endif
512
513 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
514 assert(n > 0, "cannot retrieve glibc version");
515 char *str = (char *)malloc(n, mtInternal);
516 confstr(_CS_GNU_LIBC_VERSION, str, n);
517 os::Linux::set_glibc_version(str);
518
519 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
520 assert(n > 0, "cannot retrieve pthread version");
521 str = (char *)malloc(n, mtInternal);
522 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
523 os::Linux::set_libpthread_version(str);
524 }
525
526 /////////////////////////////////////////////////////////////////////////////
527 // thread stack expansion
528
529 // os::Linux::manually_expand_stack() takes care of expanding the thread
530 // stack. Note that this is normally not needed: pthread stacks allocate
531 // thread stack using mmap() without MAP_NORESERVE, so the stack is already
532 // committed. Therefore it is not necessary to expand the stack manually.
533 //
534 // Manually expanding the stack was historically needed on LinuxThreads
535 // thread stacks, which were allocated with mmap(MAP_GROWSDOWN). Nowadays
536 // it is kept to deal with very rare corner cases:
537 //
538 // For one, user may run the VM on an own implementation of threads
539 // whose stacks are - like the old LinuxThreads - implemented using
540 // mmap(MAP_GROWSDOWN).
541 //
542 // Also, this coding may be needed if the VM is running on the primordial
543 // thread. Normally we avoid running on the primordial thread; however,
544 // user may still invoke the VM on the primordial thread.
545 //
546 // The following historical comment describes the details about running
547 // on a thread stack allocated with mmap(MAP_GROWSDOWN):
548
549
550 // Force Linux kernel to expand current thread stack. If "bottom" is close
551 // to the stack guard, caller should block all signals.
552 //
553 // MAP_GROWSDOWN:
554 // A special mmap() flag that is used to implement thread stacks. It tells
555 // kernel that the memory region should extend downwards when needed. This
556 // allows early versions of LinuxThreads to only mmap the first few pages
557 // when creating a new thread. Linux kernel will automatically expand thread
558 // stack as needed (on page faults).
559 //
560 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
561 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
562 // region, it's hard to tell if the fault is due to a legitimate stack
563 // access or because of reading/writing non-exist memory (e.g. buffer
564 // overrun). As a rule, if the fault happens below current stack pointer,
565 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
566 // application (see Linux kernel fault.c).
567 //
568 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
569 // stack overflow detection.
570 //
571 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
572 // not use MAP_GROWSDOWN.
573 //
574 // To get around the problem and allow stack banging on Linux, we need to
575 // manually expand thread stack after receiving the SIGSEGV.
576 //
577 // There are two ways to expand thread stack to address "bottom", we used
578 // both of them in JVM before 1.5:
579 // 1. adjust stack pointer first so that it is below "bottom", and then
580 // touch "bottom"
581 // 2. mmap() the page in question
582 //
583 // Now alternate signal stack is gone, it's harder to use 2. For instance,
584 // if current sp is already near the lower end of page 101, and we need to
585 // call mmap() to map page 100, it is possible that part of the mmap() frame
586 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
587 // That will destroy the mmap() frame and cause VM to crash.
588 //
589 // The following code works by adjusting sp first, then accessing the "bottom"
590 // page to force a page fault. Linux kernel will then automatically expand the
591 // stack mapping.
592 //
593 // _expand_stack_to() assumes its frame size is less than page size, which
594 // should always be true if the function is not inlined.
595
596 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
597 #define NOINLINE
598 #else
599 #define NOINLINE __attribute__ ((noinline))
600 #endif
601
602 static void _expand_stack_to(address bottom) NOINLINE;
603
604 static void _expand_stack_to(address bottom) {
605 address sp;
606 size_t size;
607 volatile char *p;
608
609 // Adjust bottom to point to the largest address within the same page, it
610 // gives us a one-page buffer if alloca() allocates slightly more memory.
611 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
612 bottom += os::Linux::page_size() - 1;
613
614 // sp might be slightly above current stack pointer; if that's the case, we
615 // will alloca() a little more space than necessary, which is OK. Don't use
616 // os::current_stack_pointer(), as its result can be slightly below current
617 // stack pointer, causing us to not alloca enough to reach "bottom".
618 sp = (address)&sp;
619
620 if (sp > bottom) {
621 size = sp - bottom;
622 p = (volatile char *)alloca(size);
623 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
624 p[0] = '\0';
625 }
626 }
627
628 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
629 assert(t!=NULL, "just checking");
630 assert(t->osthread()->expanding_stack(), "expand should be set");
631 assert(t->stack_base() != NULL, "stack_base was not initialized");
632
633 if (addr < t->stack_base() && addr >= t->stack_reserved_zone_base()) {
634 sigset_t mask_all, old_sigset;
635 sigfillset(&mask_all);
636 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
637 _expand_stack_to(addr);
638 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
639 return true;
640 }
641 return false;
642 }
643
644 //////////////////////////////////////////////////////////////////////////////
645 // create new thread
646
647 // Thread start routine for all newly created threads
648 static void *java_start(Thread *thread) {
649 // Try to randomize the cache line index of hot stack frames.
650 // This helps when threads of the same stack traces evict each other's
651 // cache lines. The threads can be either from the same JVM instance, or
652 // from different JVM instances. The benefit is especially true for
653 // processors with hyperthreading technology.
654 static int counter = 0;
655 int pid = os::current_process_id();
656 alloca(((pid ^ counter++) & 7) * 128);
657
658 thread->initialize_thread_current();
659
660 OSThread* osthread = thread->osthread();
661 Monitor* sync = osthread->startThread_lock();
662
663 osthread->set_thread_id(os::current_thread_id());
664
665 if (UseNUMA) {
666 int lgrp_id = os::numa_get_group_id();
667 if (lgrp_id != -1) {
668 thread->set_lgrp_id(lgrp_id);
669 }
670 }
671 // initialize signal mask for this thread
672 os::Linux::hotspot_sigmask(thread);
673
674 // initialize floating point control register
675 os::Linux::init_thread_fpu_state();
676
677 // handshaking with parent thread
678 {
679 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
680
681 // notify parent thread
682 osthread->set_state(INITIALIZED);
683 sync->notify_all();
684
685 // wait until os::start_thread()
686 while (osthread->get_state() == INITIALIZED) {
687 sync->wait(Mutex::_no_safepoint_check_flag);
688 }
689 }
690
691 // call one more level start routine
692 thread->run();
693
694 return 0;
695 }
696
697 bool os::create_thread(Thread* thread, ThreadType thr_type,
698 size_t stack_size) {
699 assert(thread->osthread() == NULL, "caller responsible");
700
701 // Allocate the OSThread object
702 OSThread* osthread = new OSThread(NULL, NULL);
703 if (osthread == NULL) {
704 return false;
705 }
706
707 // set the correct thread state
708 osthread->set_thread_type(thr_type);
709
710 // Initial state is ALLOCATED but not INITIALIZED
711 osthread->set_state(ALLOCATED);
712
713 thread->set_osthread(osthread);
714
715 // init thread attributes
716 pthread_attr_t attr;
717 pthread_attr_init(&attr);
718 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
719
720 // stack size
721 // calculate stack size if it's not specified by caller
722 if (stack_size == 0) {
723 stack_size = os::Linux::default_stack_size(thr_type);
724
725 switch (thr_type) {
726 case os::java_thread:
727 // Java threads use ThreadStackSize which default value can be
728 // changed with the flag -Xss
729 assert(JavaThread::stack_size_at_create() > 0, "this should be set");
730 stack_size = JavaThread::stack_size_at_create();
731 break;
732 case os::compiler_thread:
733 if (CompilerThreadStackSize > 0) {
734 stack_size = (size_t)(CompilerThreadStackSize * K);
735 break;
736 } // else fall through:
737 // use VMThreadStackSize if CompilerThreadStackSize is not defined
738 case os::vm_thread:
739 case os::pgc_thread:
740 case os::cgc_thread:
741 case os::watcher_thread:
742 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
743 break;
744 }
745 }
746
747 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
748 pthread_attr_setstacksize(&attr, stack_size);
749
750 // glibc guard page
751 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
752
753 ThreadState state;
754
755 {
756 pthread_t tid;
757 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
758
759 pthread_attr_destroy(&attr);
760
761 if (ret != 0) {
762 if (PrintMiscellaneous && (Verbose || WizardMode)) {
763 perror("pthread_create()");
764 }
765 // Need to clean up stuff we've allocated so far
766 thread->set_osthread(NULL);
767 delete osthread;
768 return false;
769 }
770
771 // Store pthread info into the OSThread
772 osthread->set_pthread_id(tid);
773
774 // Wait until child thread is either initialized or aborted
775 {
776 Monitor* sync_with_child = osthread->startThread_lock();
777 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
778 while ((state = osthread->get_state()) == ALLOCATED) {
779 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
780 }
781 }
782 }
783
784 // Aborted due to thread limit being reached
785 if (state == ZOMBIE) {
786 thread->set_osthread(NULL);
787 delete osthread;
788 return false;
789 }
790
791 // The thread is returned suspended (in state INITIALIZED),
792 // and is started higher up in the call chain
793 assert(state == INITIALIZED, "race condition");
794 return true;
795 }
796
797 /////////////////////////////////////////////////////////////////////////////
798 // attach existing thread
799
800 // bootstrap the main thread
801 bool os::create_main_thread(JavaThread* thread) {
802 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
803 return create_attached_thread(thread);
804 }
805
806 bool os::create_attached_thread(JavaThread* thread) {
807 #ifdef ASSERT
808 thread->verify_not_published();
809 #endif
810
811 // Allocate the OSThread object
812 OSThread* osthread = new OSThread(NULL, NULL);
813
814 if (osthread == NULL) {
815 return false;
816 }
817
818 // Store pthread info into the OSThread
819 osthread->set_thread_id(os::Linux::gettid());
820 osthread->set_pthread_id(::pthread_self());
821
822 // initialize floating point control register
823 os::Linux::init_thread_fpu_state();
824
825 // Initial thread state is RUNNABLE
826 osthread->set_state(RUNNABLE);
827
828 thread->set_osthread(osthread);
829
830 if (UseNUMA) {
831 int lgrp_id = os::numa_get_group_id();
832 if (lgrp_id != -1) {
833 thread->set_lgrp_id(lgrp_id);
834 }
835 }
836
837 if (os::Linux::is_initial_thread()) {
838 // If current thread is initial thread, its stack is mapped on demand,
839 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
840 // the entire stack region to avoid SEGV in stack banging.
841 // It is also useful to get around the heap-stack-gap problem on SuSE
842 // kernel (see 4821821 for details). We first expand stack to the top
843 // of yellow zone, then enable stack yellow zone (order is significant,
844 // enabling yellow zone first will crash JVM on SuSE Linux), so there
845 // is no gap between the last two virtual memory regions.
846
847 JavaThread *jt = (JavaThread *)thread;
848 address addr = jt->stack_reserved_zone_base();
849 assert(addr != NULL, "initialization problem?");
850 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
851
852 osthread->set_expanding_stack();
853 os::Linux::manually_expand_stack(jt, addr);
854 osthread->clear_expanding_stack();
855 }
856
857 // initialize signal mask for this thread
858 // and save the caller's signal mask
859 os::Linux::hotspot_sigmask(thread);
860
861 return true;
862 }
863
864 void os::pd_start_thread(Thread* thread) {
865 OSThread * osthread = thread->osthread();
866 assert(osthread->get_state() != INITIALIZED, "just checking");
867 Monitor* sync_with_child = osthread->startThread_lock();
868 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
869 sync_with_child->notify();
870 }
871
872 // Free Linux resources related to the OSThread
873 void os::free_thread(OSThread* osthread) {
874 assert(osthread != NULL, "osthread not set");
875
876 if (Thread::current()->osthread() == osthread) {
877 // Restore caller's signal mask
878 sigset_t sigmask = osthread->caller_sigmask();
879 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
880 }
881
882 delete osthread;
883 }
884
885 //////////////////////////////////////////////////////////////////////////////
886 // initial thread
887
888 // Check if current thread is the initial thread, similar to Solaris thr_main.
889 bool os::Linux::is_initial_thread(void) {
890 char dummy;
891 // If called before init complete, thread stack bottom will be null.
892 // Can be called if fatal error occurs before initialization.
893 if (initial_thread_stack_bottom() == NULL) return false;
894 assert(initial_thread_stack_bottom() != NULL &&
895 initial_thread_stack_size() != 0,
896 "os::init did not locate initial thread's stack region");
897 if ((address)&dummy >= initial_thread_stack_bottom() &&
898 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size()) {
899 return true;
900 } else {
901 return false;
902 }
903 }
904
905 // Find the virtual memory area that contains addr
906 static bool find_vma(address addr, address* vma_low, address* vma_high) {
907 FILE *fp = fopen("/proc/self/maps", "r");
908 if (fp) {
909 address low, high;
910 while (!feof(fp)) {
911 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
912 if (low <= addr && addr < high) {
913 if (vma_low) *vma_low = low;
914 if (vma_high) *vma_high = high;
915 fclose(fp);
916 return true;
917 }
918 }
919 for (;;) {
920 int ch = fgetc(fp);
921 if (ch == EOF || ch == (int)'\n') break;
922 }
923 }
924 fclose(fp);
925 }
926 return false;
927 }
928
929 // Locate initial thread stack. This special handling of initial thread stack
930 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
931 // bogus value for initial thread.
932 void os::Linux::capture_initial_stack(size_t max_size) {
933 // stack size is the easy part, get it from RLIMIT_STACK
934 size_t stack_size;
935 struct rlimit rlim;
936 getrlimit(RLIMIT_STACK, &rlim);
937 stack_size = rlim.rlim_cur;
938
939 // 6308388: a bug in ld.so will relocate its own .data section to the
940 // lower end of primordial stack; reduce ulimit -s value a little bit
941 // so we won't install guard page on ld.so's data section.
942 stack_size -= 2 * page_size();
943
944 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
945 // 7.1, in both cases we will get 2G in return value.
946 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
947 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
948 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
949 // in case other parts in glibc still assumes 2M max stack size.
950 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
951 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
952 if (stack_size > 2 * K * K IA64_ONLY(*2)) {
953 stack_size = 2 * K * K IA64_ONLY(*2);
954 }
955 // Try to figure out where the stack base (top) is. This is harder.
956 //
957 // When an application is started, glibc saves the initial stack pointer in
958 // a global variable "__libc_stack_end", which is then used by system
959 // libraries. __libc_stack_end should be pretty close to stack top. The
960 // variable is available since the very early days. However, because it is
961 // a private interface, it could disappear in the future.
962 //
963 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
964 // to __libc_stack_end, it is very close to stack top, but isn't the real
965 // stack top. Note that /proc may not exist if VM is running as a chroot
966 // program, so reading /proc/<pid>/stat could fail. Also the contents of
967 // /proc/<pid>/stat could change in the future (though unlikely).
968 //
969 // We try __libc_stack_end first. If that doesn't work, look for
970 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
971 // as a hint, which should work well in most cases.
972
973 uintptr_t stack_start;
974
975 // try __libc_stack_end first
976 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
977 if (p && *p) {
978 stack_start = *p;
979 } else {
980 // see if we can get the start_stack field from /proc/self/stat
981 FILE *fp;
982 int pid;
983 char state;
984 int ppid;
985 int pgrp;
986 int session;
987 int nr;
988 int tpgrp;
989 unsigned long flags;
990 unsigned long minflt;
991 unsigned long cminflt;
992 unsigned long majflt;
993 unsigned long cmajflt;
994 unsigned long utime;
995 unsigned long stime;
996 long cutime;
997 long cstime;
998 long prio;
999 long nice;
1000 long junk;
1001 long it_real;
1002 uintptr_t start;
1003 uintptr_t vsize;
1004 intptr_t rss;
1005 uintptr_t rsslim;
1006 uintptr_t scodes;
1007 uintptr_t ecode;
1008 int i;
1009
1010 // Figure what the primordial thread stack base is. Code is inspired
1011 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1012 // followed by command name surrounded by parentheses, state, etc.
1013 char stat[2048];
1014 int statlen;
1015
1016 fp = fopen("/proc/self/stat", "r");
1017 if (fp) {
1018 statlen = fread(stat, 1, 2047, fp);
1019 stat[statlen] = '\0';
1020 fclose(fp);
1021
1022 // Skip pid and the command string. Note that we could be dealing with
1023 // weird command names, e.g. user could decide to rename java launcher
1024 // to "java 1.4.2 :)", then the stat file would look like
1025 // 1234 (java 1.4.2 :)) R ... ...
1026 // We don't really need to know the command string, just find the last
1027 // occurrence of ")" and then start parsing from there. See bug 4726580.
1028 char * s = strrchr(stat, ')');
1029
1030 i = 0;
1031 if (s) {
1032 // Skip blank chars
1033 do { s++; } while (s && isspace(*s));
1034
1035 #define _UFM UINTX_FORMAT
1036 #define _DFM INTX_FORMAT
1037
1038 // 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2
1039 // 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
1040 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,
1041 &state, // 3 %c
1042 &ppid, // 4 %d
1043 &pgrp, // 5 %d
1044 &session, // 6 %d
1045 &nr, // 7 %d
1046 &tpgrp, // 8 %d
1047 &flags, // 9 %lu
1048 &minflt, // 10 %lu
1049 &cminflt, // 11 %lu
1050 &majflt, // 12 %lu
1051 &cmajflt, // 13 %lu
1052 &utime, // 14 %lu
1053 &stime, // 15 %lu
1054 &cutime, // 16 %ld
1055 &cstime, // 17 %ld
1056 &prio, // 18 %ld
1057 &nice, // 19 %ld
1058 &junk, // 20 %ld
1059 &it_real, // 21 %ld
1060 &start, // 22 UINTX_FORMAT
1061 &vsize, // 23 UINTX_FORMAT
1062 &rss, // 24 INTX_FORMAT
1063 &rsslim, // 25 UINTX_FORMAT
1064 &scodes, // 26 UINTX_FORMAT
1065 &ecode, // 27 UINTX_FORMAT
1066 &stack_start); // 28 UINTX_FORMAT
1067 }
1068
1069 #undef _UFM
1070 #undef _DFM
1071
1072 if (i != 28 - 2) {
1073 assert(false, "Bad conversion from /proc/self/stat");
1074 // product mode - assume we are the initial thread, good luck in the
1075 // embedded case.
1076 warning("Can't detect initial thread stack location - bad conversion");
1077 stack_start = (uintptr_t) &rlim;
1078 }
1079 } else {
1080 // For some reason we can't open /proc/self/stat (for example, running on
1081 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1082 // most cases, so don't abort:
1083 warning("Can't detect initial thread stack location - no /proc/self/stat");
1084 stack_start = (uintptr_t) &rlim;
1085 }
1086 }
1087
1088 // Now we have a pointer (stack_start) very close to the stack top, the
1089 // next thing to do is to figure out the exact location of stack top. We
1090 // can find out the virtual memory area that contains stack_start by
1091 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1092 // and its upper limit is the real stack top. (again, this would fail if
1093 // running inside chroot, because /proc may not exist.)
1094
1095 uintptr_t stack_top;
1096 address low, high;
1097 if (find_vma((address)stack_start, &low, &high)) {
1098 // success, "high" is the true stack top. (ignore "low", because initial
1099 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1100 stack_top = (uintptr_t)high;
1101 } else {
1102 // failed, likely because /proc/self/maps does not exist
1103 warning("Can't detect initial thread stack location - find_vma failed");
1104 // best effort: stack_start is normally within a few pages below the real
1105 // stack top, use it as stack top, and reduce stack size so we won't put
1106 // guard page outside stack.
1107 stack_top = stack_start;
1108 stack_size -= 16 * page_size();
1109 }
1110
1111 // stack_top could be partially down the page so align it
1112 stack_top = align_size_up(stack_top, page_size());
1113
1114 if (max_size && stack_size > max_size) {
1115 _initial_thread_stack_size = max_size;
1116 } else {
1117 _initial_thread_stack_size = stack_size;
1118 }
1119
1120 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1121 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1122 }
1123
1124 ////////////////////////////////////////////////////////////////////////////////
1125 // time support
1126
1127 // Time since start-up in seconds to a fine granularity.
1128 // Used by VMSelfDestructTimer and the MemProfiler.
1129 double os::elapsedTime() {
1130
1131 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1132 }
1133
1134 jlong os::elapsed_counter() {
1135 return javaTimeNanos() - initial_time_count;
1136 }
1137
1138 jlong os::elapsed_frequency() {
1139 return NANOSECS_PER_SEC; // nanosecond resolution
1140 }
1141
1142 bool os::supports_vtime() { return true; }
1143 bool os::enable_vtime() { return false; }
1144 bool os::vtime_enabled() { return false; }
1145
1146 double os::elapsedVTime() {
1147 struct rusage usage;
1148 int retval = getrusage(RUSAGE_THREAD, &usage);
1149 if (retval == 0) {
1150 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1151 } else {
1152 // better than nothing, but not much
1153 return elapsedTime();
1154 }
1155 }
1156
1157 jlong os::javaTimeMillis() {
1158 timeval time;
1159 int status = gettimeofday(&time, NULL);
1160 assert(status != -1, "linux error");
1161 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1162 }
1163
1164 void os::javaTimeSystemUTC(jlong &seconds, jlong &nanos) {
1165 timeval time;
1166 int status = gettimeofday(&time, NULL);
1167 assert(status != -1, "linux error");
1168 seconds = jlong(time.tv_sec);
1169 nanos = jlong(time.tv_usec) * 1000;
1170 }
1171
1172
1173 #ifndef CLOCK_MONOTONIC
1174 #define CLOCK_MONOTONIC (1)
1175 #endif
1176
1177 void os::Linux::clock_init() {
1178 // we do dlopen's in this particular order due to bug in linux
1179 // dynamical loader (see 6348968) leading to crash on exit
1180 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1181 if (handle == NULL) {
1182 handle = dlopen("librt.so", RTLD_LAZY);
1183 }
1184
1185 if (handle) {
1186 int (*clock_getres_func)(clockid_t, struct timespec*) =
1187 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1188 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1189 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1190 if (clock_getres_func && clock_gettime_func) {
1191 // See if monotonic clock is supported by the kernel. Note that some
1192 // early implementations simply return kernel jiffies (updated every
1193 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1194 // for nano time (though the monotonic property is still nice to have).
1195 // It's fixed in newer kernels, however clock_getres() still returns
1196 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1197 // resolution for now. Hopefully as people move to new kernels, this
1198 // won't be a problem.
1199 struct timespec res;
1200 struct timespec tp;
1201 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1202 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1203 // yes, monotonic clock is supported
1204 _clock_gettime = clock_gettime_func;
1205 return;
1206 } else {
1207 // close librt if there is no monotonic clock
1208 dlclose(handle);
1209 }
1210 }
1211 }
1212 warning("No monotonic clock was available - timed services may " \
1213 "be adversely affected if the time-of-day clock changes");
1214 }
1215
1216 #ifndef SYS_clock_getres
1217 #if defined(IA32) || defined(AMD64)
1218 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1219 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1220 #else
1221 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1222 #define sys_clock_getres(x,y) -1
1223 #endif
1224 #else
1225 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1226 #endif
1227
1228 void os::Linux::fast_thread_clock_init() {
1229 if (!UseLinuxPosixThreadCPUClocks) {
1230 return;
1231 }
1232 clockid_t clockid;
1233 struct timespec tp;
1234 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1235 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1236
1237 // Switch to using fast clocks for thread cpu time if
1238 // the sys_clock_getres() returns 0 error code.
1239 // Note, that some kernels may support the current thread
1240 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1241 // returned by the pthread_getcpuclockid().
1242 // If the fast Posix clocks are supported then the sys_clock_getres()
1243 // must return at least tp.tv_sec == 0 which means a resolution
1244 // better than 1 sec. This is extra check for reliability.
1245
1246 if (pthread_getcpuclockid_func &&
1247 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1248 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1249 _supports_fast_thread_cpu_time = true;
1250 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1251 }
1252 }
1253
1254 jlong os::javaTimeNanos() {
1255 if (os::supports_monotonic_clock()) {
1256 struct timespec tp;
1257 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1258 assert(status == 0, "gettime error");
1259 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1260 return result;
1261 } else {
1262 timeval time;
1263 int status = gettimeofday(&time, NULL);
1264 assert(status != -1, "linux error");
1265 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1266 return 1000 * usecs;
1267 }
1268 }
1269
1270 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1271 if (os::supports_monotonic_clock()) {
1272 info_ptr->max_value = ALL_64_BITS;
1273
1274 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1275 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1276 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1277 } else {
1278 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1279 info_ptr->max_value = ALL_64_BITS;
1280
1281 // gettimeofday is a real time clock so it skips
1282 info_ptr->may_skip_backward = true;
1283 info_ptr->may_skip_forward = true;
1284 }
1285
1286 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1287 }
1288
1289 // Return the real, user, and system times in seconds from an
1290 // arbitrary fixed point in the past.
1291 bool os::getTimesSecs(double* process_real_time,
1292 double* process_user_time,
1293 double* process_system_time) {
1294 struct tms ticks;
1295 clock_t real_ticks = times(&ticks);
1296
1297 if (real_ticks == (clock_t) (-1)) {
1298 return false;
1299 } else {
1300 double ticks_per_second = (double) clock_tics_per_sec;
1301 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1302 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1303 *process_real_time = ((double) real_ticks) / ticks_per_second;
1304
1305 return true;
1306 }
1307 }
1308
1309
1310 char * os::local_time_string(char *buf, size_t buflen) {
1311 struct tm t;
1312 time_t long_time;
1313 time(&long_time);
1314 localtime_r(&long_time, &t);
1315 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1316 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1317 t.tm_hour, t.tm_min, t.tm_sec);
1318 return buf;
1319 }
1320
1321 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1322 return localtime_r(clock, res);
1323 }
1324
1325 ////////////////////////////////////////////////////////////////////////////////
1326 // runtime exit support
1327
1328 // Note: os::shutdown() might be called very early during initialization, or
1329 // called from signal handler. Before adding something to os::shutdown(), make
1330 // sure it is async-safe and can handle partially initialized VM.
1331 void os::shutdown() {
1332
1333 // allow PerfMemory to attempt cleanup of any persistent resources
1334 perfMemory_exit();
1335
1336 // needs to remove object in file system
1337 AttachListener::abort();
1338
1339 // flush buffered output, finish log files
1340 ostream_abort();
1341
1342 // Check for abort hook
1343 abort_hook_t abort_hook = Arguments::abort_hook();
1344 if (abort_hook != NULL) {
1345 abort_hook();
1346 }
1347
1348 }
1349
1350 // Note: os::abort() might be called very early during initialization, or
1351 // called from signal handler. Before adding something to os::abort(), make
1352 // sure it is async-safe and can handle partially initialized VM.
1353 void os::abort(bool dump_core, void* siginfo, const void* context) {
1354 os::shutdown();
1355 if (dump_core) {
1356 #ifndef PRODUCT
1357 fdStream out(defaultStream::output_fd());
1358 out.print_raw("Current thread is ");
1359 char buf[16];
1360 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1361 out.print_raw_cr(buf);
1362 out.print_raw_cr("Dumping core ...");
1363 #endif
1364 ::abort(); // dump core
1365 }
1366
1367 ::exit(1);
1368 }
1369
1370 // Die immediately, no exit hook, no abort hook, no cleanup.
1371 void os::die() {
1372 ::abort();
1373 }
1374
1375
1376 // This method is a copy of JDK's sysGetLastErrorString
1377 // from src/solaris/hpi/src/system_md.c
1378
1379 size_t os::lasterror(char *buf, size_t len) {
1380 if (errno == 0) return 0;
1381
1382 const char *s = ::strerror(errno);
1383 size_t n = ::strlen(s);
1384 if (n >= len) {
1385 n = len - 1;
1386 }
1387 ::strncpy(buf, s, n);
1388 buf[n] = '\0';
1389 return n;
1390 }
1391
1392 // thread_id is kernel thread id (similar to Solaris LWP id)
1393 intx os::current_thread_id() { return os::Linux::gettid(); }
1394 int os::current_process_id() {
1395 return ::getpid();
1396 }
1397
1398 // DLL functions
1399
1400 const char* os::dll_file_extension() { return ".so"; }
1401
1402 // This must be hard coded because it's the system's temporary
1403 // directory not the java application's temp directory, ala java.io.tmpdir.
1404 const char* os::get_temp_directory() { return "/tmp"; }
1405
1406 static bool file_exists(const char* filename) {
1407 struct stat statbuf;
1408 if (filename == NULL || strlen(filename) == 0) {
1409 return false;
1410 }
1411 return os::stat(filename, &statbuf) == 0;
1412 }
1413
1414 bool os::dll_build_name(char* buffer, size_t buflen,
1415 const char* pname, const char* fname) {
1416 bool retval = false;
1417 // Copied from libhpi
1418 const size_t pnamelen = pname ? strlen(pname) : 0;
1419
1420 // Return error on buffer overflow.
1421 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1422 return retval;
1423 }
1424
1425 if (pnamelen == 0) {
1426 snprintf(buffer, buflen, "lib%s.so", fname);
1427 retval = true;
1428 } else if (strchr(pname, *os::path_separator()) != NULL) {
1429 int n;
1430 char** pelements = split_path(pname, &n);
1431 if (pelements == NULL) {
1432 return false;
1433 }
1434 for (int i = 0; i < n; i++) {
1435 // Really shouldn't be NULL, but check can't hurt
1436 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1437 continue; // skip the empty path values
1438 }
1439 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1440 if (file_exists(buffer)) {
1441 retval = true;
1442 break;
1443 }
1444 }
1445 // release the storage
1446 for (int i = 0; i < n; i++) {
1447 if (pelements[i] != NULL) {
1448 FREE_C_HEAP_ARRAY(char, pelements[i]);
1449 }
1450 }
1451 if (pelements != NULL) {
1452 FREE_C_HEAP_ARRAY(char*, pelements);
1453 }
1454 } else {
1455 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1456 retval = true;
1457 }
1458 return retval;
1459 }
1460
1461 // check if addr is inside libjvm.so
1462 bool os::address_is_in_vm(address addr) {
1463 static address libjvm_base_addr;
1464 Dl_info dlinfo;
1465
1466 if (libjvm_base_addr == NULL) {
1467 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1468 libjvm_base_addr = (address)dlinfo.dli_fbase;
1469 }
1470 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1471 }
1472
1473 if (dladdr((void *)addr, &dlinfo) != 0) {
1474 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1475 }
1476
1477 return false;
1478 }
1479
1480 bool os::dll_address_to_function_name(address addr, char *buf,
1481 int buflen, int *offset,
1482 bool demangle) {
1483 // buf is not optional, but offset is optional
1484 assert(buf != NULL, "sanity check");
1485
1486 Dl_info dlinfo;
1487
1488 if (dladdr((void*)addr, &dlinfo) != 0) {
1489 // see if we have a matching symbol
1490 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1491 if (!(demangle && Decoder::demangle(dlinfo.dli_sname, buf, buflen))) {
1492 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1493 }
1494 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1495 return true;
1496 }
1497 // no matching symbol so try for just file info
1498 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1499 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1500 buf, buflen, offset, dlinfo.dli_fname, demangle)) {
1501 return true;
1502 }
1503 }
1504 }
1505
1506 buf[0] = '\0';
1507 if (offset != NULL) *offset = -1;
1508 return false;
1509 }
1510
1511 struct _address_to_library_name {
1512 address addr; // input : memory address
1513 size_t buflen; // size of fname
1514 char* fname; // output: library name
1515 address base; // library base addr
1516 };
1517
1518 static int address_to_library_name_callback(struct dl_phdr_info *info,
1519 size_t size, void *data) {
1520 int i;
1521 bool found = false;
1522 address libbase = NULL;
1523 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1524
1525 // iterate through all loadable segments
1526 for (i = 0; i < info->dlpi_phnum; i++) {
1527 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1528 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1529 // base address of a library is the lowest address of its loaded
1530 // segments.
1531 if (libbase == NULL || libbase > segbase) {
1532 libbase = segbase;
1533 }
1534 // see if 'addr' is within current segment
1535 if (segbase <= d->addr &&
1536 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1537 found = true;
1538 }
1539 }
1540 }
1541
1542 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1543 // so dll_address_to_library_name() can fall through to use dladdr() which
1544 // can figure out executable name from argv[0].
1545 if (found && info->dlpi_name && info->dlpi_name[0]) {
1546 d->base = libbase;
1547 if (d->fname) {
1548 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1549 }
1550 return 1;
1551 }
1552 return 0;
1553 }
1554
1555 bool os::dll_address_to_library_name(address addr, char* buf,
1556 int buflen, int* offset) {
1557 // buf is not optional, but offset is optional
1558 assert(buf != NULL, "sanity check");
1559
1560 Dl_info dlinfo;
1561 struct _address_to_library_name data;
1562
1563 // There is a bug in old glibc dladdr() implementation that it could resolve
1564 // to wrong library name if the .so file has a base address != NULL. Here
1565 // we iterate through the program headers of all loaded libraries to find
1566 // out which library 'addr' really belongs to. This workaround can be
1567 // removed once the minimum requirement for glibc is moved to 2.3.x.
1568 data.addr = addr;
1569 data.fname = buf;
1570 data.buflen = buflen;
1571 data.base = NULL;
1572 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1573
1574 if (rslt) {
1575 // buf already contains library name
1576 if (offset) *offset = addr - data.base;
1577 return true;
1578 }
1579 if (dladdr((void*)addr, &dlinfo) != 0) {
1580 if (dlinfo.dli_fname != NULL) {
1581 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1582 }
1583 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1584 *offset = addr - (address)dlinfo.dli_fbase;
1585 }
1586 return true;
1587 }
1588
1589 buf[0] = '\0';
1590 if (offset) *offset = -1;
1591 return false;
1592 }
1593
1594 // Loads .dll/.so and
1595 // in case of error it checks if .dll/.so was built for the
1596 // same architecture as Hotspot is running on
1597
1598
1599 // Remember the stack's state. The Linux dynamic linker will change
1600 // the stack to 'executable' at most once, so we must safepoint only once.
1601 bool os::Linux::_stack_is_executable = false;
1602
1603 // VM operation that loads a library. This is necessary if stack protection
1604 // of the Java stacks can be lost during loading the library. If we
1605 // do not stop the Java threads, they can stack overflow before the stacks
1606 // are protected again.
1607 class VM_LinuxDllLoad: public VM_Operation {
1608 private:
1609 const char *_filename;
1610 char *_ebuf;
1611 int _ebuflen;
1612 void *_lib;
1613 public:
1614 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1615 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1616 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1617 void doit() {
1618 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1619 os::Linux::_stack_is_executable = true;
1620 }
1621 void* loaded_library() { return _lib; }
1622 };
1623
1624 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1625 void * result = NULL;
1626 bool load_attempted = false;
1627
1628 // Check whether the library to load might change execution rights
1629 // of the stack. If they are changed, the protection of the stack
1630 // guard pages will be lost. We need a safepoint to fix this.
1631 //
1632 // See Linux man page execstack(8) for more info.
1633 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1634 ElfFile ef(filename);
1635 if (!ef.specifies_noexecstack()) {
1636 if (!is_init_completed()) {
1637 os::Linux::_stack_is_executable = true;
1638 // This is OK - No Java threads have been created yet, and hence no
1639 // stack guard pages to fix.
1640 //
1641 // This should happen only when you are building JDK7 using a very
1642 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1643 //
1644 // Dynamic loader will make all stacks executable after
1645 // this function returns, and will not do that again.
1646 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1647 } else {
1648 warning("You have loaded library %s which might have disabled stack guard. "
1649 "The VM will try to fix the stack guard now.\n"
1650 "It's highly recommended that you fix the library with "
1651 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1652 filename);
1653
1654 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1655 JavaThread *jt = JavaThread::current();
1656 if (jt->thread_state() != _thread_in_native) {
1657 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1658 // that requires ExecStack. Cannot enter safe point. Let's give up.
1659 warning("Unable to fix stack guard. Giving up.");
1660 } else {
1661 if (!LoadExecStackDllInVMThread) {
1662 // This is for the case where the DLL has an static
1663 // constructor function that executes JNI code. We cannot
1664 // load such DLLs in the VMThread.
1665 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1666 }
1667
1668 ThreadInVMfromNative tiv(jt);
1669 debug_only(VMNativeEntryWrapper vew;)
1670
1671 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1672 VMThread::execute(&op);
1673 if (LoadExecStackDllInVMThread) {
1674 result = op.loaded_library();
1675 }
1676 load_attempted = true;
1677 }
1678 }
1679 }
1680 }
1681
1682 if (!load_attempted) {
1683 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1684 }
1685
1686 if (result != NULL) {
1687 // Successful loading
1688 return result;
1689 }
1690
1691 Elf32_Ehdr elf_head;
1692 int diag_msg_max_length=ebuflen-strlen(ebuf);
1693 char* diag_msg_buf=ebuf+strlen(ebuf);
1694
1695 if (diag_msg_max_length==0) {
1696 // No more space in ebuf for additional diagnostics message
1697 return NULL;
1698 }
1699
1700
1701 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1702
1703 if (file_descriptor < 0) {
1704 // Can't open library, report dlerror() message
1705 return NULL;
1706 }
1707
1708 bool failed_to_read_elf_head=
1709 (sizeof(elf_head)!=
1710 (::read(file_descriptor, &elf_head,sizeof(elf_head))));
1711
1712 ::close(file_descriptor);
1713 if (failed_to_read_elf_head) {
1714 // file i/o error - report dlerror() msg
1715 return NULL;
1716 }
1717
1718 typedef struct {
1719 Elf32_Half code; // Actual value as defined in elf.h
1720 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1721 char elf_class; // 32 or 64 bit
1722 char endianess; // MSB or LSB
1723 char* name; // String representation
1724 } arch_t;
1725
1726 #ifndef EM_486
1727 #define EM_486 6 /* Intel 80486 */
1728 #endif
1729 #ifndef EM_AARCH64
1730 #define EM_AARCH64 183 /* ARM AARCH64 */
1731 #endif
1732
1733 static const arch_t arch_array[]={
1734 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1735 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1736 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1737 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1738 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1739 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1740 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1741 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1742 #if defined(VM_LITTLE_ENDIAN)
1743 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64"},
1744 #else
1745 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64 LE"},
1746 #endif
1747 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1748 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1749 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1750 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1751 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1752 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1753 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"},
1754 {EM_AARCH64, EM_AARCH64, ELFCLASS64, ELFDATA2LSB, (char*)"AARCH64"},
1755 };
1756
1757 #if (defined IA32)
1758 static Elf32_Half running_arch_code=EM_386;
1759 #elif (defined AMD64)
1760 static Elf32_Half running_arch_code=EM_X86_64;
1761 #elif (defined IA64)
1762 static Elf32_Half running_arch_code=EM_IA_64;
1763 #elif (defined __sparc) && (defined _LP64)
1764 static Elf32_Half running_arch_code=EM_SPARCV9;
1765 #elif (defined __sparc) && (!defined _LP64)
1766 static Elf32_Half running_arch_code=EM_SPARC;
1767 #elif (defined __powerpc64__)
1768 static Elf32_Half running_arch_code=EM_PPC64;
1769 #elif (defined __powerpc__)
1770 static Elf32_Half running_arch_code=EM_PPC;
1771 #elif (defined ARM)
1772 static Elf32_Half running_arch_code=EM_ARM;
1773 #elif (defined S390)
1774 static Elf32_Half running_arch_code=EM_S390;
1775 #elif (defined ALPHA)
1776 static Elf32_Half running_arch_code=EM_ALPHA;
1777 #elif (defined MIPSEL)
1778 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1779 #elif (defined PARISC)
1780 static Elf32_Half running_arch_code=EM_PARISC;
1781 #elif (defined MIPS)
1782 static Elf32_Half running_arch_code=EM_MIPS;
1783 #elif (defined M68K)
1784 static Elf32_Half running_arch_code=EM_68K;
1785 #elif (defined AARCH64)
1786 static Elf32_Half running_arch_code=EM_AARCH64;
1787 #else
1788 #error Method os::dll_load requires that one of following is defined:\
1789 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K, AARCH64
1790 #endif
1791
1792 // Identify compatability class for VM's architecture and library's architecture
1793 // Obtain string descriptions for architectures
1794
1795 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1796 int running_arch_index=-1;
1797
1798 for (unsigned int i=0; i < ARRAY_SIZE(arch_array); i++) {
1799 if (running_arch_code == arch_array[i].code) {
1800 running_arch_index = i;
1801 }
1802 if (lib_arch.code == arch_array[i].code) {
1803 lib_arch.compat_class = arch_array[i].compat_class;
1804 lib_arch.name = arch_array[i].name;
1805 }
1806 }
1807
1808 assert(running_arch_index != -1,
1809 "Didn't find running architecture code (running_arch_code) in arch_array");
1810 if (running_arch_index == -1) {
1811 // Even though running architecture detection failed
1812 // we may still continue with reporting dlerror() message
1813 return NULL;
1814 }
1815
1816 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1817 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1818 return NULL;
1819 }
1820
1821 #ifndef S390
1822 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1823 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1824 return NULL;
1825 }
1826 #endif // !S390
1827
1828 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1829 if (lib_arch.name!=NULL) {
1830 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1831 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1832 lib_arch.name, arch_array[running_arch_index].name);
1833 } else {
1834 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1835 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1836 lib_arch.code,
1837 arch_array[running_arch_index].name);
1838 }
1839 }
1840
1841 return NULL;
1842 }
1843
1844 void * os::Linux::dlopen_helper(const char *filename, char *ebuf,
1845 int ebuflen) {
1846 void * result = ::dlopen(filename, RTLD_LAZY);
1847 if (result == NULL) {
1848 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
1849 ebuf[ebuflen-1] = '\0';
1850 }
1851 return result;
1852 }
1853
1854 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf,
1855 int ebuflen) {
1856 void * result = NULL;
1857 if (LoadExecStackDllInVMThread) {
1858 result = dlopen_helper(filename, ebuf, ebuflen);
1859 }
1860
1861 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
1862 // library that requires an executable stack, or which does not have this
1863 // stack attribute set, dlopen changes the stack attribute to executable. The
1864 // read protection of the guard pages gets lost.
1865 //
1866 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
1867 // may have been queued at the same time.
1868
1869 if (!_stack_is_executable) {
1870 JavaThread *jt = Threads::first();
1871
1872 while (jt) {
1873 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
1874 jt->stack_guards_enabled()) { // No pending stack overflow exceptions
1875 if (!os::guard_memory((char *)jt->stack_end(), jt->stack_guard_zone_size())) {
1876 warning("Attempt to reguard stack yellow zone failed.");
1877 }
1878 }
1879 jt = jt->next();
1880 }
1881 }
1882
1883 return result;
1884 }
1885
1886 void* os::dll_lookup(void* handle, const char* name) {
1887 void* res = dlsym(handle, name);
1888 return res;
1889 }
1890
1891 void* os::get_default_process_handle() {
1892 return (void*)::dlopen(NULL, RTLD_LAZY);
1893 }
1894
1895 static bool _print_ascii_file(const char* filename, outputStream* st) {
1896 int fd = ::open(filename, O_RDONLY);
1897 if (fd == -1) {
1898 return false;
1899 }
1900
1901 char buf[32];
1902 int bytes;
1903 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
1904 st->print_raw(buf, bytes);
1905 }
1906
1907 ::close(fd);
1908
1909 return true;
1910 }
1911
1912 void os::print_dll_info(outputStream *st) {
1913 st->print_cr("Dynamic libraries:");
1914
1915 char fname[32];
1916 pid_t pid = os::Linux::gettid();
1917
1918 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1919
1920 if (!_print_ascii_file(fname, st)) {
1921 st->print("Can not get library information for pid = %d\n", pid);
1922 }
1923 }
1924
1925 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
1926 FILE *procmapsFile = NULL;
1927
1928 // Open the procfs maps file for the current process
1929 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
1930 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
1931 char line[PATH_MAX + 100];
1932
1933 // Read line by line from 'file'
1934 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
1935 u8 base, top, offset, inode;
1936 char permissions[5];
1937 char device[6];
1938 char name[PATH_MAX + 1];
1939
1940 // Parse fields from line
1941 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %5s " INT64_FORMAT " %s",
1942 &base, &top, permissions, &offset, device, &inode, name);
1943
1944 // Filter by device id '00:00' so that we only get file system mapped files.
1945 if (strcmp(device, "00:00") != 0) {
1946
1947 // Call callback with the fields of interest
1948 if(callback(name, (address)base, (address)top, param)) {
1949 // Oops abort, callback aborted
1950 fclose(procmapsFile);
1951 return 1;
1952 }
1953 }
1954 }
1955 fclose(procmapsFile);
1956 }
1957 return 0;
1958 }
1959
1960 void os::print_os_info_brief(outputStream* st) {
1961 os::Linux::print_distro_info(st);
1962
1963 os::Posix::print_uname_info(st);
1964
1965 os::Linux::print_libversion_info(st);
1966
1967 }
1968
1969 void os::print_os_info(outputStream* st) {
1970 st->print("OS:");
1971
1972 os::Linux::print_distro_info(st);
1973
1974 os::Posix::print_uname_info(st);
1975
1976 // Print warning if unsafe chroot environment detected
1977 if (unsafe_chroot_detected) {
1978 st->print("WARNING!! ");
1979 st->print_cr("%s", unstable_chroot_error);
1980 }
1981
1982 os::Linux::print_libversion_info(st);
1983
1984 os::Posix::print_rlimit_info(st);
1985
1986 os::Posix::print_load_average(st);
1987
1988 os::Linux::print_full_memory_info(st);
1989 }
1990
1991 // Try to identify popular distros.
1992 // Most Linux distributions have a /etc/XXX-release file, which contains
1993 // the OS version string. Newer Linux distributions have a /etc/lsb-release
1994 // file that also contains the OS version string. Some have more than one
1995 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
1996 // /etc/redhat-release.), so the order is important.
1997 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
1998 // their own specific XXX-release file as well as a redhat-release file.
1999 // Because of this the XXX-release file needs to be searched for before the
2000 // redhat-release file.
2001 // Since Red Hat has a lsb-release file that is not very descriptive the
2002 // search for redhat-release needs to be before lsb-release.
2003 // Since the lsb-release file is the new standard it needs to be searched
2004 // before the older style release files.
2005 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2006 // next to last resort. The os-release file is a new standard that contains
2007 // distribution information and the system-release file seems to be an old
2008 // standard that has been replaced by the lsb-release and os-release files.
2009 // Searching for the debian_version file is the last resort. It contains
2010 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2011 // "Debian " is printed before the contents of the debian_version file.
2012
2013 const char* distro_files[] = {
2014 "/etc/oracle-release",
2015 "/etc/mandriva-release",
2016 "/etc/mandrake-release",
2017 "/etc/sun-release",
2018 "/etc/redhat-release",
2019 "/etc/lsb-release",
2020 "/etc/SuSE-release",
2021 "/etc/turbolinux-release",
2022 "/etc/gentoo-release",
2023 "/etc/ltib-release",
2024 "/etc/angstrom-version",
2025 "/etc/system-release",
2026 "/etc/os-release",
2027 NULL };
2028
2029 void os::Linux::print_distro_info(outputStream* st) {
2030 for (int i = 0;; i++) {
2031 const char* file = distro_files[i];
2032 if (file == NULL) {
2033 break; // done
2034 }
2035 // If file prints, we found it.
2036 if (_print_ascii_file(file, st)) {
2037 return;
2038 }
2039 }
2040
2041 if (file_exists("/etc/debian_version")) {
2042 st->print("Debian ");
2043 _print_ascii_file("/etc/debian_version", st);
2044 } else {
2045 st->print("Linux");
2046 }
2047 st->cr();
2048 }
2049
2050 static void parse_os_info(char* distro, size_t length, const char* file) {
2051 FILE* fp = fopen(file, "r");
2052 if (fp != NULL) {
2053 char buf[256];
2054 // get last line of the file.
2055 while (fgets(buf, sizeof(buf), fp)) { }
2056 // Edit out extra stuff in expected ubuntu format
2057 if (strstr(buf, "DISTRIB_DESCRIPTION=") != NULL) {
2058 char* ptr = strstr(buf, "\""); // the name is in quotes
2059 if (ptr != NULL) {
2060 ptr++; // go beyond first quote
2061 char* nl = strchr(ptr, '\"');
2062 if (nl != NULL) *nl = '\0';
2063 strncpy(distro, ptr, length);
2064 } else {
2065 ptr = strstr(buf, "=");
2066 ptr++; // go beyond equals then
2067 char* nl = strchr(ptr, '\n');
2068 if (nl != NULL) *nl = '\0';
2069 strncpy(distro, ptr, length);
2070 }
2071 } else {
2072 // if not in expected Ubuntu format, print out whole line minus \n
2073 char* nl = strchr(buf, '\n');
2074 if (nl != NULL) *nl = '\0';
2075 strncpy(distro, buf, length);
2076 }
2077 // close distro file
2078 fclose(fp);
2079 }
2080 }
2081
2082 void os::get_summary_os_info(char* buf, size_t buflen) {
2083 for (int i = 0;; i++) {
2084 const char* file = distro_files[i];
2085 if (file == NULL) {
2086 break; // ran out of distro_files
2087 }
2088 if (file_exists(file)) {
2089 parse_os_info(buf, buflen, file);
2090 return;
2091 }
2092 }
2093 // special case for debian
2094 if (file_exists("/etc/debian_version")) {
2095 strncpy(buf, "Debian ", buflen);
2096 parse_os_info(&buf[7], buflen-7, "/etc/debian_version");
2097 } else {
2098 strncpy(buf, "Linux", buflen);
2099 }
2100 }
2101
2102 void os::Linux::print_libversion_info(outputStream* st) {
2103 // libc, pthread
2104 st->print("libc:");
2105 st->print("%s ", os::Linux::glibc_version());
2106 st->print("%s ", os::Linux::libpthread_version());
2107 st->cr();
2108 }
2109
2110 void os::Linux::print_full_memory_info(outputStream* st) {
2111 st->print("\n/proc/meminfo:\n");
2112 _print_ascii_file("/proc/meminfo", st);
2113 st->cr();
2114 }
2115
2116 void os::print_memory_info(outputStream* st) {
2117
2118 st->print("Memory:");
2119 st->print(" %dk page", os::vm_page_size()>>10);
2120
2121 // values in struct sysinfo are "unsigned long"
2122 struct sysinfo si;
2123 sysinfo(&si);
2124
2125 st->print(", physical " UINT64_FORMAT "k",
2126 os::physical_memory() >> 10);
2127 st->print("(" UINT64_FORMAT "k free)",
2128 os::available_memory() >> 10);
2129 st->print(", swap " UINT64_FORMAT "k",
2130 ((jlong)si.totalswap * si.mem_unit) >> 10);
2131 st->print("(" UINT64_FORMAT "k free)",
2132 ((jlong)si.freeswap * si.mem_unit) >> 10);
2133 st->cr();
2134 }
2135
2136 // Print the first "model name" line and the first "flags" line
2137 // that we find and nothing more. We assume "model name" comes
2138 // before "flags" so if we find a second "model name", then the
2139 // "flags" field is considered missing.
2140 static bool print_model_name_and_flags(outputStream* st, char* buf, size_t buflen) {
2141 #if defined(IA32) || defined(AMD64)
2142 // Other platforms have less repetitive cpuinfo files
2143 FILE *fp = fopen("/proc/cpuinfo", "r");
2144 if (fp) {
2145 while (!feof(fp)) {
2146 if (fgets(buf, buflen, fp)) {
2147 // Assume model name comes before flags
2148 bool model_name_printed = false;
2149 if (strstr(buf, "model name") != NULL) {
2150 if (!model_name_printed) {
2151 st->print_raw("\nCPU Model and flags from /proc/cpuinfo:\n");
2152 st->print_raw(buf);
2153 model_name_printed = true;
2154 } else {
2155 // model name printed but not flags? Odd, just return
2156 fclose(fp);
2157 return true;
2158 }
2159 }
2160 // print the flags line too
2161 if (strstr(buf, "flags") != NULL) {
2162 st->print_raw(buf);
2163 fclose(fp);
2164 return true;
2165 }
2166 }
2167 }
2168 fclose(fp);
2169 }
2170 #endif // x86 platforms
2171 return false;
2172 }
2173
2174 void os::pd_print_cpu_info(outputStream* st, char* buf, size_t buflen) {
2175 // Only print the model name if the platform provides this as a summary
2176 if (!print_model_name_and_flags(st, buf, buflen)) {
2177 st->print("\n/proc/cpuinfo:\n");
2178 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2179 st->print_cr(" <Not Available>");
2180 }
2181 }
2182 }
2183
2184 #if defined(AMD64) || defined(IA32) || defined(X32)
2185 const char* search_string = "model name";
2186 #elif defined(SPARC)
2187 const char* search_string = "cpu";
2188 #elif defined(PPC64)
2189 const char* search_string = "cpu";
2190 #else
2191 const char* search_string = "Processor";
2192 #endif
2193
2194 // Parses the cpuinfo file for string representing the model name.
2195 void os::get_summary_cpu_info(char* cpuinfo, size_t length) {
2196 FILE* fp = fopen("/proc/cpuinfo", "r");
2197 if (fp != NULL) {
2198 while (!feof(fp)) {
2199 char buf[256];
2200 if (fgets(buf, sizeof(buf), fp)) {
2201 char* start = strstr(buf, search_string);
2202 if (start != NULL) {
2203 char *ptr = start + strlen(search_string);
2204 char *end = buf + strlen(buf);
2205 while (ptr != end) {
2206 // skip whitespace and colon for the rest of the name.
2207 if (*ptr != ' ' && *ptr != '\t' && *ptr != ':') {
2208 break;
2209 }
2210 ptr++;
2211 }
2212 if (ptr != end) {
2213 // reasonable string, get rid of newline and keep the rest
2214 char* nl = strchr(buf, '\n');
2215 if (nl != NULL) *nl = '\0';
2216 strncpy(cpuinfo, ptr, length);
2217 fclose(fp);
2218 return;
2219 }
2220 }
2221 }
2222 }
2223 fclose(fp);
2224 }
2225 // cpuinfo not found or parsing failed, just print generic string. The entire
2226 // /proc/cpuinfo file will be printed later in the file (or enough of it for x86)
2227 #if defined(AMD64)
2228 strncpy(cpuinfo, "x86_64", length);
2229 #elif defined(IA32)
2230 strncpy(cpuinfo, "x86_32", length);
2231 #elif defined(IA64)
2232 strncpy(cpuinfo, "IA64", length);
2233 #elif defined(SPARC)
2234 strncpy(cpuinfo, "sparcv9", length);
2235 #elif defined(AARCH64)
2236 strncpy(cpuinfo, "AArch64", length);
2237 #elif defined(ARM)
2238 strncpy(cpuinfo, "ARM", length);
2239 #elif defined(PPC)
2240 strncpy(cpuinfo, "PPC64", length);
2241 #elif defined(ZERO_LIBARCH)
2242 strncpy(cpuinfo, ZERO_LIBARCH, length);
2243 #else
2244 strncpy(cpuinfo, "unknown", length);
2245 #endif
2246 }
2247
2248 static void print_signal_handler(outputStream* st, int sig,
2249 char* buf, size_t buflen);
2250
2251 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2252 st->print_cr("Signal Handlers:");
2253 print_signal_handler(st, SIGSEGV, buf, buflen);
2254 print_signal_handler(st, SIGBUS , buf, buflen);
2255 print_signal_handler(st, SIGFPE , buf, buflen);
2256 print_signal_handler(st, SIGPIPE, buf, buflen);
2257 print_signal_handler(st, SIGXFSZ, buf, buflen);
2258 print_signal_handler(st, SIGILL , buf, buflen);
2259 print_signal_handler(st, SR_signum, buf, buflen);
2260 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2261 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2262 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2263 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2264 #if defined(PPC64)
2265 print_signal_handler(st, SIGTRAP, buf, buflen);
2266 #endif
2267 }
2268
2269 static char saved_jvm_path[MAXPATHLEN] = {0};
2270
2271 // Find the full path to the current module, libjvm.so
2272 void os::jvm_path(char *buf, jint buflen) {
2273 // Error checking.
2274 if (buflen < MAXPATHLEN) {
2275 assert(false, "must use a large-enough buffer");
2276 buf[0] = '\0';
2277 return;
2278 }
2279 // Lazy resolve the path to current module.
2280 if (saved_jvm_path[0] != 0) {
2281 strcpy(buf, saved_jvm_path);
2282 return;
2283 }
2284
2285 char dli_fname[MAXPATHLEN];
2286 bool ret = dll_address_to_library_name(
2287 CAST_FROM_FN_PTR(address, os::jvm_path),
2288 dli_fname, sizeof(dli_fname), NULL);
2289 assert(ret, "cannot locate libjvm");
2290 char *rp = NULL;
2291 if (ret && dli_fname[0] != '\0') {
2292 rp = realpath(dli_fname, buf);
2293 }
2294 if (rp == NULL) {
2295 return;
2296 }
2297
2298 if (Arguments::sun_java_launcher_is_altjvm()) {
2299 // Support for the java launcher's '-XXaltjvm=<path>' option. Typical
2300 // value for buf is "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so".
2301 // If "/jre/lib/" appears at the right place in the string, then
2302 // assume we are installed in a JDK and we're done. Otherwise, check
2303 // for a JAVA_HOME environment variable and fix up the path so it
2304 // looks like libjvm.so is installed there (append a fake suffix
2305 // hotspot/libjvm.so).
2306 const char *p = buf + strlen(buf) - 1;
2307 for (int count = 0; p > buf && count < 5; ++count) {
2308 for (--p; p > buf && *p != '/'; --p)
2309 /* empty */ ;
2310 }
2311
2312 if (strncmp(p, "/jre/lib/", 9) != 0) {
2313 // Look for JAVA_HOME in the environment.
2314 char* java_home_var = ::getenv("JAVA_HOME");
2315 if (java_home_var != NULL && java_home_var[0] != 0) {
2316 char* jrelib_p;
2317 int len;
2318
2319 // Check the current module name "libjvm.so".
2320 p = strrchr(buf, '/');
2321 if (p == NULL) {
2322 return;
2323 }
2324 assert(strstr(p, "/libjvm") == p, "invalid library name");
2325
2326 rp = realpath(java_home_var, buf);
2327 if (rp == NULL) {
2328 return;
2329 }
2330
2331 // determine if this is a legacy image or modules image
2332 // modules image doesn't have "jre" subdirectory
2333 len = strlen(buf);
2334 assert(len < buflen, "Ran out of buffer room");
2335 jrelib_p = buf + len;
2336 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2337 if (0 != access(buf, F_OK)) {
2338 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2339 }
2340
2341 if (0 == access(buf, F_OK)) {
2342 // Use current module name "libjvm.so"
2343 len = strlen(buf);
2344 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2345 } else {
2346 // Go back to path of .so
2347 rp = realpath(dli_fname, buf);
2348 if (rp == NULL) {
2349 return;
2350 }
2351 }
2352 }
2353 }
2354 }
2355
2356 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2357 saved_jvm_path[MAXPATHLEN - 1] = '\0';
2358 }
2359
2360 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2361 // no prefix required, not even "_"
2362 }
2363
2364 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2365 // no suffix required
2366 }
2367
2368 ////////////////////////////////////////////////////////////////////////////////
2369 // sun.misc.Signal support
2370
2371 static volatile jint sigint_count = 0;
2372
2373 static void UserHandler(int sig, void *siginfo, void *context) {
2374 // 4511530 - sem_post is serialized and handled by the manager thread. When
2375 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2376 // don't want to flood the manager thread with sem_post requests.
2377 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1) {
2378 return;
2379 }
2380
2381 // Ctrl-C is pressed during error reporting, likely because the error
2382 // handler fails to abort. Let VM die immediately.
2383 if (sig == SIGINT && is_error_reported()) {
2384 os::die();
2385 }
2386
2387 os::signal_notify(sig);
2388 }
2389
2390 void* os::user_handler() {
2391 return CAST_FROM_FN_PTR(void*, UserHandler);
2392 }
2393
2394 struct timespec PosixSemaphore::create_timespec(unsigned int sec, int nsec) {
2395 struct timespec ts;
2396 // Semaphore's are always associated with CLOCK_REALTIME
2397 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2398 // see unpackTime for discussion on overflow checking
2399 if (sec >= MAX_SECS) {
2400 ts.tv_sec += MAX_SECS;
2401 ts.tv_nsec = 0;
2402 } else {
2403 ts.tv_sec += sec;
2404 ts.tv_nsec += nsec;
2405 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2406 ts.tv_nsec -= NANOSECS_PER_SEC;
2407 ++ts.tv_sec; // note: this must be <= max_secs
2408 }
2409 }
2410
2411 return ts;
2412 }
2413
2414 extern "C" {
2415 typedef void (*sa_handler_t)(int);
2416 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2417 }
2418
2419 void* os::signal(int signal_number, void* handler) {
2420 struct sigaction sigAct, oldSigAct;
2421
2422 sigfillset(&(sigAct.sa_mask));
2423 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2424 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2425
2426 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2427 // -1 means registration failed
2428 return (void *)-1;
2429 }
2430
2431 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2432 }
2433
2434 void os::signal_raise(int signal_number) {
2435 ::raise(signal_number);
2436 }
2437
2438 // The following code is moved from os.cpp for making this
2439 // code platform specific, which it is by its very nature.
2440
2441 // Will be modified when max signal is changed to be dynamic
2442 int os::sigexitnum_pd() {
2443 return NSIG;
2444 }
2445
2446 // a counter for each possible signal value
2447 static volatile jint pending_signals[NSIG+1] = { 0 };
2448
2449 // Linux(POSIX) specific hand shaking semaphore.
2450 static sem_t sig_sem;
2451 static PosixSemaphore sr_semaphore;
2452
2453 void os::signal_init_pd() {
2454 // Initialize signal structures
2455 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2456
2457 // Initialize signal semaphore
2458 ::sem_init(&sig_sem, 0, 0);
2459 }
2460
2461 void os::signal_notify(int sig) {
2462 Atomic::inc(&pending_signals[sig]);
2463 ::sem_post(&sig_sem);
2464 }
2465
2466 static int check_pending_signals(bool wait) {
2467 Atomic::store(0, &sigint_count);
2468 for (;;) {
2469 for (int i = 0; i < NSIG + 1; i++) {
2470 jint n = pending_signals[i];
2471 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2472 return i;
2473 }
2474 }
2475 if (!wait) {
2476 return -1;
2477 }
2478 JavaThread *thread = JavaThread::current();
2479 ThreadBlockInVM tbivm(thread);
2480
2481 bool threadIsSuspended;
2482 do {
2483 thread->set_suspend_equivalent();
2484 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2485 ::sem_wait(&sig_sem);
2486
2487 // were we externally suspended while we were waiting?
2488 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2489 if (threadIsSuspended) {
2490 // The semaphore has been incremented, but while we were waiting
2491 // another thread suspended us. We don't want to continue running
2492 // while suspended because that would surprise the thread that
2493 // suspended us.
2494 ::sem_post(&sig_sem);
2495
2496 thread->java_suspend_self();
2497 }
2498 } while (threadIsSuspended);
2499 }
2500 }
2501
2502 int os::signal_lookup() {
2503 return check_pending_signals(false);
2504 }
2505
2506 int os::signal_wait() {
2507 return check_pending_signals(true);
2508 }
2509
2510 ////////////////////////////////////////////////////////////////////////////////
2511 // Virtual Memory
2512
2513 int os::vm_page_size() {
2514 // Seems redundant as all get out
2515 assert(os::Linux::page_size() != -1, "must call os::init");
2516 return os::Linux::page_size();
2517 }
2518
2519 // Solaris allocates memory by pages.
2520 int os::vm_allocation_granularity() {
2521 assert(os::Linux::page_size() != -1, "must call os::init");
2522 return os::Linux::page_size();
2523 }
2524
2525 // Rationale behind this function:
2526 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2527 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2528 // samples for JITted code. Here we create private executable mapping over the code cache
2529 // and then we can use standard (well, almost, as mapping can change) way to provide
2530 // info for the reporting script by storing timestamp and location of symbol
2531 void linux_wrap_code(char* base, size_t size) {
2532 static volatile jint cnt = 0;
2533
2534 if (!UseOprofile) {
2535 return;
2536 }
2537
2538 char buf[PATH_MAX+1];
2539 int num = Atomic::add(1, &cnt);
2540
2541 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2542 os::get_temp_directory(), os::current_process_id(), num);
2543 unlink(buf);
2544
2545 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2546
2547 if (fd != -1) {
2548 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2549 if (rv != (off_t)-1) {
2550 if (::write(fd, "", 1) == 1) {
2551 mmap(base, size,
2552 PROT_READ|PROT_WRITE|PROT_EXEC,
2553 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2554 }
2555 }
2556 ::close(fd);
2557 unlink(buf);
2558 }
2559 }
2560
2561 static bool recoverable_mmap_error(int err) {
2562 // See if the error is one we can let the caller handle. This
2563 // list of errno values comes from JBS-6843484. I can't find a
2564 // Linux man page that documents this specific set of errno
2565 // values so while this list currently matches Solaris, it may
2566 // change as we gain experience with this failure mode.
2567 switch (err) {
2568 case EBADF:
2569 case EINVAL:
2570 case ENOTSUP:
2571 // let the caller deal with these errors
2572 return true;
2573
2574 default:
2575 // Any remaining errors on this OS can cause our reserved mapping
2576 // to be lost. That can cause confusion where different data
2577 // structures think they have the same memory mapped. The worst
2578 // scenario is if both the VM and a library think they have the
2579 // same memory mapped.
2580 return false;
2581 }
2582 }
2583
2584 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2585 int err) {
2586 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2587 ", %d) failed; error='%s' (errno=%d)", p2i(addr), size, exec,
2588 strerror(err), err);
2589 }
2590
2591 static void warn_fail_commit_memory(char* addr, size_t size,
2592 size_t alignment_hint, bool exec,
2593 int err) {
2594 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2595 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", p2i(addr), size,
2596 alignment_hint, exec, strerror(err), err);
2597 }
2598
2599 // NOTE: Linux kernel does not really reserve the pages for us.
2600 // All it does is to check if there are enough free pages
2601 // left at the time of mmap(). This could be a potential
2602 // problem.
2603 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2604 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2605 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2606 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2607 if (res != (uintptr_t) MAP_FAILED) {
2608 if (UseNUMAInterleaving) {
2609 numa_make_global(addr, size);
2610 }
2611 return 0;
2612 }
2613
2614 int err = errno; // save errno from mmap() call above
2615
2616 if (!recoverable_mmap_error(err)) {
2617 warn_fail_commit_memory(addr, size, exec, err);
2618 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2619 }
2620
2621 return err;
2622 }
2623
2624 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2625 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2626 }
2627
2628 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2629 const char* mesg) {
2630 assert(mesg != NULL, "mesg must be specified");
2631 int err = os::Linux::commit_memory_impl(addr, size, exec);
2632 if (err != 0) {
2633 // the caller wants all commit errors to exit with the specified mesg:
2634 warn_fail_commit_memory(addr, size, exec, err);
2635 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2636 }
2637 }
2638
2639 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2640 #ifndef MAP_HUGETLB
2641 #define MAP_HUGETLB 0x40000
2642 #endif
2643
2644 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2645 #ifndef MADV_HUGEPAGE
2646 #define MADV_HUGEPAGE 14
2647 #endif
2648
2649 int os::Linux::commit_memory_impl(char* addr, size_t size,
2650 size_t alignment_hint, bool exec) {
2651 int err = os::Linux::commit_memory_impl(addr, size, exec);
2652 if (err == 0) {
2653 realign_memory(addr, size, alignment_hint);
2654 }
2655 return err;
2656 }
2657
2658 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2659 bool exec) {
2660 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2661 }
2662
2663 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2664 size_t alignment_hint, bool exec,
2665 const char* mesg) {
2666 assert(mesg != NULL, "mesg must be specified");
2667 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2668 if (err != 0) {
2669 // the caller wants all commit errors to exit with the specified mesg:
2670 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2671 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "%s", mesg);
2672 }
2673 }
2674
2675 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2676 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2677 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2678 // be supported or the memory may already be backed by huge pages.
2679 ::madvise(addr, bytes, MADV_HUGEPAGE);
2680 }
2681 }
2682
2683 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2684 // This method works by doing an mmap over an existing mmaping and effectively discarding
2685 // the existing pages. However it won't work for SHM-based large pages that cannot be
2686 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2687 // small pages on top of the SHM segment. This method always works for small pages, so we
2688 // allow that in any case.
2689 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2690 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2691 }
2692 }
2693
2694 void os::numa_make_global(char *addr, size_t bytes) {
2695 Linux::numa_interleave_memory(addr, bytes);
2696 }
2697
2698 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2699 // bind policy to MPOL_PREFERRED for the current thread.
2700 #define USE_MPOL_PREFERRED 0
2701
2702 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2703 // To make NUMA and large pages more robust when both enabled, we need to ease
2704 // the requirements on where the memory should be allocated. MPOL_BIND is the
2705 // default policy and it will force memory to be allocated on the specified
2706 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2707 // the specified node, but will not force it. Using this policy will prevent
2708 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2709 // free large pages.
2710 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2711 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2712 }
2713
2714 bool os::numa_topology_changed() { return false; }
2715
2716 size_t os::numa_get_groups_num() {
2717 int max_node = Linux::numa_max_node();
2718 return max_node > 0 ? max_node + 1 : 1;
2719 }
2720
2721 int os::numa_get_group_id() {
2722 int cpu_id = Linux::sched_getcpu();
2723 if (cpu_id != -1) {
2724 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2725 if (lgrp_id != -1) {
2726 return lgrp_id;
2727 }
2728 }
2729 return 0;
2730 }
2731
2732 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2733 for (size_t i = 0; i < size; i++) {
2734 ids[i] = i;
2735 }
2736 return size;
2737 }
2738
2739 bool os::get_page_info(char *start, page_info* info) {
2740 return false;
2741 }
2742
2743 char *os::scan_pages(char *start, char* end, page_info* page_expected,
2744 page_info* page_found) {
2745 return end;
2746 }
2747
2748
2749 int os::Linux::sched_getcpu_syscall(void) {
2750 unsigned int cpu = 0;
2751 int retval = -1;
2752
2753 #if defined(IA32)
2754 #ifndef SYS_getcpu
2755 #define SYS_getcpu 318
2756 #endif
2757 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2758 #elif defined(AMD64)
2759 // Unfortunately we have to bring all these macros here from vsyscall.h
2760 // to be able to compile on old linuxes.
2761 #define __NR_vgetcpu 2
2762 #define VSYSCALL_START (-10UL << 20)
2763 #define VSYSCALL_SIZE 1024
2764 #define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2765 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2766 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2767 retval = vgetcpu(&cpu, NULL, NULL);
2768 #endif
2769
2770 return (retval == -1) ? retval : cpu;
2771 }
2772
2773 // Something to do with the numa-aware allocator needs these symbols
2774 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2775 extern "C" JNIEXPORT void numa_error(char *where) { }
2776
2777
2778 // If we are running with libnuma version > 2, then we should
2779 // be trying to use symbols with versions 1.1
2780 // If we are running with earlier version, which did not have symbol versions,
2781 // we should use the base version.
2782 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2783 void *f = dlvsym(handle, name, "libnuma_1.1");
2784 if (f == NULL) {
2785 f = dlsym(handle, name);
2786 }
2787 return f;
2788 }
2789
2790 bool os::Linux::libnuma_init() {
2791 // sched_getcpu() should be in libc.
2792 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2793 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2794
2795 // If it's not, try a direct syscall.
2796 if (sched_getcpu() == -1) {
2797 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2798 (void*)&sched_getcpu_syscall));
2799 }
2800
2801 if (sched_getcpu() != -1) { // Does it work?
2802 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2803 if (handle != NULL) {
2804 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2805 libnuma_dlsym(handle, "numa_node_to_cpus")));
2806 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2807 libnuma_dlsym(handle, "numa_max_node")));
2808 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2809 libnuma_dlsym(handle, "numa_available")));
2810 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2811 libnuma_dlsym(handle, "numa_tonode_memory")));
2812 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2813 libnuma_dlsym(handle, "numa_interleave_memory")));
2814 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
2815 libnuma_dlsym(handle, "numa_set_bind_policy")));
2816
2817
2818 if (numa_available() != -1) {
2819 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2820 // Create a cpu -> node mapping
2821 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2822 rebuild_cpu_to_node_map();
2823 return true;
2824 }
2825 }
2826 }
2827 return false;
2828 }
2829
2830 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2831 // The table is later used in get_node_by_cpu().
2832 void os::Linux::rebuild_cpu_to_node_map() {
2833 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2834 // in libnuma (possible values are starting from 16,
2835 // and continuing up with every other power of 2, but less
2836 // than the maximum number of CPUs supported by kernel), and
2837 // is a subject to change (in libnuma version 2 the requirements
2838 // are more reasonable) we'll just hardcode the number they use
2839 // in the library.
2840 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2841
2842 size_t cpu_num = os::active_processor_count();
2843 size_t cpu_map_size = NCPUS / BitsPerCLong;
2844 size_t cpu_map_valid_size =
2845 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2846
2847 cpu_to_node()->clear();
2848 cpu_to_node()->at_grow(cpu_num - 1);
2849 size_t node_num = numa_get_groups_num();
2850
2851 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2852 for (size_t i = 0; i < node_num; i++) {
2853 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2854 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2855 if (cpu_map[j] != 0) {
2856 for (size_t k = 0; k < BitsPerCLong; k++) {
2857 if (cpu_map[j] & (1UL << k)) {
2858 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2859 }
2860 }
2861 }
2862 }
2863 }
2864 }
2865 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2866 }
2867
2868 int os::Linux::get_node_by_cpu(int cpu_id) {
2869 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2870 return cpu_to_node()->at(cpu_id);
2871 }
2872 return -1;
2873 }
2874
2875 GrowableArray<int>* os::Linux::_cpu_to_node;
2876 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2877 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2878 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2879 os::Linux::numa_available_func_t os::Linux::_numa_available;
2880 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2881 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2882 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
2883 unsigned long* os::Linux::_numa_all_nodes;
2884
2885 bool os::pd_uncommit_memory(char* addr, size_t size) {
2886 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2887 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2888 return res != (uintptr_t) MAP_FAILED;
2889 }
2890
2891 static address get_stack_commited_bottom(address bottom, size_t size) {
2892 address nbot = bottom;
2893 address ntop = bottom + size;
2894
2895 size_t page_sz = os::vm_page_size();
2896 unsigned pages = size / page_sz;
2897
2898 unsigned char vec[1];
2899 unsigned imin = 1, imax = pages + 1, imid;
2900 int mincore_return_value = 0;
2901
2902 assert(imin <= imax, "Unexpected page size");
2903
2904 while (imin < imax) {
2905 imid = (imax + imin) / 2;
2906 nbot = ntop - (imid * page_sz);
2907
2908 // Use a trick with mincore to check whether the page is mapped or not.
2909 // mincore sets vec to 1 if page resides in memory and to 0 if page
2910 // is swapped output but if page we are asking for is unmapped
2911 // it returns -1,ENOMEM
2912 mincore_return_value = mincore(nbot, page_sz, vec);
2913
2914 if (mincore_return_value == -1) {
2915 // Page is not mapped go up
2916 // to find first mapped page
2917 if (errno != EAGAIN) {
2918 assert(errno == ENOMEM, "Unexpected mincore errno");
2919 imax = imid;
2920 }
2921 } else {
2922 // Page is mapped go down
2923 // to find first not mapped page
2924 imin = imid + 1;
2925 }
2926 }
2927
2928 nbot = nbot + page_sz;
2929
2930 // Adjust stack bottom one page up if last checked page is not mapped
2931 if (mincore_return_value == -1) {
2932 nbot = nbot + page_sz;
2933 }
2934
2935 return nbot;
2936 }
2937
2938
2939 // Linux uses a growable mapping for the stack, and if the mapping for
2940 // the stack guard pages is not removed when we detach a thread the
2941 // stack cannot grow beyond the pages where the stack guard was
2942 // mapped. If at some point later in the process the stack expands to
2943 // that point, the Linux kernel cannot expand the stack any further
2944 // because the guard pages are in the way, and a segfault occurs.
2945 //
2946 // However, it's essential not to split the stack region by unmapping
2947 // a region (leaving a hole) that's already part of the stack mapping,
2948 // so if the stack mapping has already grown beyond the guard pages at
2949 // the time we create them, we have to truncate the stack mapping.
2950 // So, we need to know the extent of the stack mapping when
2951 // create_stack_guard_pages() is called.
2952
2953 // We only need this for stacks that are growable: at the time of
2954 // writing thread stacks don't use growable mappings (i.e. those
2955 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2956 // only applies to the main thread.
2957
2958 // If the (growable) stack mapping already extends beyond the point
2959 // where we're going to put our guard pages, truncate the mapping at
2960 // that point by munmap()ping it. This ensures that when we later
2961 // munmap() the guard pages we don't leave a hole in the stack
2962 // mapping. This only affects the main/initial thread
2963
2964 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2965 if (os::Linux::is_initial_thread()) {
2966 // As we manually grow stack up to bottom inside create_attached_thread(),
2967 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
2968 // we don't need to do anything special.
2969 // Check it first, before calling heavy function.
2970 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
2971 unsigned char vec[1];
2972
2973 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
2974 // Fallback to slow path on all errors, including EAGAIN
2975 stack_extent = (uintptr_t) get_stack_commited_bottom(
2976 os::Linux::initial_thread_stack_bottom(),
2977 (size_t)addr - stack_extent);
2978 }
2979
2980 if (stack_extent < (uintptr_t)addr) {
2981 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
2982 }
2983 }
2984
2985 return os::commit_memory(addr, size, !ExecMem);
2986 }
2987
2988 // If this is a growable mapping, remove the guard pages entirely by
2989 // munmap()ping them. If not, just call uncommit_memory(). This only
2990 // affects the main/initial thread, but guard against future OS changes
2991 // It's safe to always unmap guard pages for initial thread because we
2992 // always place it right after end of the mapped region
2993
2994 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2995 uintptr_t stack_extent, stack_base;
2996
2997 if (os::Linux::is_initial_thread()) {
2998 return ::munmap(addr, size) == 0;
2999 }
3000
3001 return os::uncommit_memory(addr, size);
3002 }
3003
3004 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3005 // at 'requested_addr'. If there are existing memory mappings at the same
3006 // location, however, they will be overwritten. If 'fixed' is false,
3007 // 'requested_addr' is only treated as a hint, the return value may or
3008 // may not start from the requested address. Unlike Linux mmap(), this
3009 // function returns NULL to indicate failure.
3010 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3011 char * addr;
3012 int flags;
3013
3014 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3015 if (fixed) {
3016 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3017 flags |= MAP_FIXED;
3018 }
3019
3020 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3021 // touch an uncommitted page. Otherwise, the read/write might
3022 // succeed if we have enough swap space to back the physical page.
3023 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3024 flags, -1, 0);
3025
3026 return addr == MAP_FAILED ? NULL : addr;
3027 }
3028
3029 static int anon_munmap(char * addr, size_t size) {
3030 return ::munmap(addr, size) == 0;
3031 }
3032
3033 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3034 size_t alignment_hint) {
3035 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3036 }
3037
3038 bool os::pd_release_memory(char* addr, size_t size) {
3039 return anon_munmap(addr, size);
3040 }
3041
3042 static bool linux_mprotect(char* addr, size_t size, int prot) {
3043 // Linux wants the mprotect address argument to be page aligned.
3044 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3045
3046 // According to SUSv3, mprotect() should only be used with mappings
3047 // established by mmap(), and mmap() always maps whole pages. Unaligned
3048 // 'addr' likely indicates problem in the VM (e.g. trying to change
3049 // protection of malloc'ed or statically allocated memory). Check the
3050 // caller if you hit this assert.
3051 assert(addr == bottom, "sanity check");
3052
3053 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3054 return ::mprotect(bottom, size, prot) == 0;
3055 }
3056
3057 // Set protections specified
3058 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3059 bool is_committed) {
3060 unsigned int p = 0;
3061 switch (prot) {
3062 case MEM_PROT_NONE: p = PROT_NONE; break;
3063 case MEM_PROT_READ: p = PROT_READ; break;
3064 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3065 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3066 default:
3067 ShouldNotReachHere();
3068 }
3069 // is_committed is unused.
3070 return linux_mprotect(addr, bytes, p);
3071 }
3072
3073 bool os::guard_memory(char* addr, size_t size) {
3074 return linux_mprotect(addr, size, PROT_NONE);
3075 }
3076
3077 bool os::unguard_memory(char* addr, size_t size) {
3078 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3079 }
3080
3081 bool os::Linux::transparent_huge_pages_sanity_check(bool warn,
3082 size_t page_size) {
3083 bool result = false;
3084 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3085 MAP_ANONYMOUS|MAP_PRIVATE,
3086 -1, 0);
3087 if (p != MAP_FAILED) {
3088 void *aligned_p = align_ptr_up(p, page_size);
3089
3090 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3091
3092 munmap(p, page_size * 2);
3093 }
3094
3095 if (warn && !result) {
3096 warning("TransparentHugePages is not supported by the operating system.");
3097 }
3098
3099 return result;
3100 }
3101
3102 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3103 bool result = false;
3104 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3105 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3106 -1, 0);
3107
3108 if (p != MAP_FAILED) {
3109 // We don't know if this really is a huge page or not.
3110 FILE *fp = fopen("/proc/self/maps", "r");
3111 if (fp) {
3112 while (!feof(fp)) {
3113 char chars[257];
3114 long x = 0;
3115 if (fgets(chars, sizeof(chars), fp)) {
3116 if (sscanf(chars, "%lx-%*x", &x) == 1
3117 && x == (long)p) {
3118 if (strstr (chars, "hugepage")) {
3119 result = true;
3120 break;
3121 }
3122 }
3123 }
3124 }
3125 fclose(fp);
3126 }
3127 munmap(p, page_size);
3128 }
3129
3130 if (warn && !result) {
3131 warning("HugeTLBFS is not supported by the operating system.");
3132 }
3133
3134 return result;
3135 }
3136
3137 // Set the coredump_filter bits to include largepages in core dump (bit 6)
3138 //
3139 // From the coredump_filter documentation:
3140 //
3141 // - (bit 0) anonymous private memory
3142 // - (bit 1) anonymous shared memory
3143 // - (bit 2) file-backed private memory
3144 // - (bit 3) file-backed shared memory
3145 // - (bit 4) ELF header pages in file-backed private memory areas (it is
3146 // effective only if the bit 2 is cleared)
3147 // - (bit 5) hugetlb private memory
3148 // - (bit 6) hugetlb shared memory
3149 //
3150 static void set_coredump_filter(void) {
3151 FILE *f;
3152 long cdm;
3153
3154 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3155 return;
3156 }
3157
3158 if (fscanf(f, "%lx", &cdm) != 1) {
3159 fclose(f);
3160 return;
3161 }
3162
3163 rewind(f);
3164
3165 if ((cdm & LARGEPAGES_BIT) == 0) {
3166 cdm |= LARGEPAGES_BIT;
3167 fprintf(f, "%#lx", cdm);
3168 }
3169
3170 fclose(f);
3171 }
3172
3173 // Large page support
3174
3175 static size_t _large_page_size = 0;
3176
3177 size_t os::Linux::find_large_page_size() {
3178 size_t large_page_size = 0;
3179
3180 // large_page_size on Linux is used to round up heap size. x86 uses either
3181 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3182 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3183 // page as large as 256M.
3184 //
3185 // Here we try to figure out page size by parsing /proc/meminfo and looking
3186 // for a line with the following format:
3187 // Hugepagesize: 2048 kB
3188 //
3189 // If we can't determine the value (e.g. /proc is not mounted, or the text
3190 // format has been changed), we'll use the largest page size supported by
3191 // the processor.
3192
3193 #ifndef ZERO
3194 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3195 ARM32_ONLY(2 * M) PPC_ONLY(4 * M) AARCH64_ONLY(2 * M);
3196 #endif // ZERO
3197
3198 FILE *fp = fopen("/proc/meminfo", "r");
3199 if (fp) {
3200 while (!feof(fp)) {
3201 int x = 0;
3202 char buf[16];
3203 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3204 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3205 large_page_size = x * K;
3206 break;
3207 }
3208 } else {
3209 // skip to next line
3210 for (;;) {
3211 int ch = fgetc(fp);
3212 if (ch == EOF || ch == (int)'\n') break;
3213 }
3214 }
3215 }
3216 fclose(fp);
3217 }
3218
3219 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3220 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3221 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3222 proper_unit_for_byte_size(large_page_size));
3223 }
3224
3225 return large_page_size;
3226 }
3227
3228 size_t os::Linux::setup_large_page_size() {
3229 _large_page_size = Linux::find_large_page_size();
3230 const size_t default_page_size = (size_t)Linux::page_size();
3231 if (_large_page_size > default_page_size) {
3232 _page_sizes[0] = _large_page_size;
3233 _page_sizes[1] = default_page_size;
3234 _page_sizes[2] = 0;
3235 }
3236
3237 return _large_page_size;
3238 }
3239
3240 bool os::Linux::setup_large_page_type(size_t page_size) {
3241 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3242 FLAG_IS_DEFAULT(UseSHM) &&
3243 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3244
3245 // The type of large pages has not been specified by the user.
3246
3247 // Try UseHugeTLBFS and then UseSHM.
3248 UseHugeTLBFS = UseSHM = true;
3249
3250 // Don't try UseTransparentHugePages since there are known
3251 // performance issues with it turned on. This might change in the future.
3252 UseTransparentHugePages = false;
3253 }
3254
3255 if (UseTransparentHugePages) {
3256 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3257 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3258 UseHugeTLBFS = false;
3259 UseSHM = false;
3260 return true;
3261 }
3262 UseTransparentHugePages = false;
3263 }
3264
3265 if (UseHugeTLBFS) {
3266 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3267 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3268 UseSHM = false;
3269 return true;
3270 }
3271 UseHugeTLBFS = false;
3272 }
3273
3274 return UseSHM;
3275 }
3276
3277 void os::large_page_init() {
3278 if (!UseLargePages &&
3279 !UseTransparentHugePages &&
3280 !UseHugeTLBFS &&
3281 !UseSHM) {
3282 // Not using large pages.
3283 return;
3284 }
3285
3286 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3287 // The user explicitly turned off large pages.
3288 // Ignore the rest of the large pages flags.
3289 UseTransparentHugePages = false;
3290 UseHugeTLBFS = false;
3291 UseSHM = false;
3292 return;
3293 }
3294
3295 size_t large_page_size = Linux::setup_large_page_size();
3296 UseLargePages = Linux::setup_large_page_type(large_page_size);
3297
3298 set_coredump_filter();
3299 }
3300
3301 #ifndef SHM_HUGETLB
3302 #define SHM_HUGETLB 04000
3303 #endif
3304
3305 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment,
3306 char* req_addr, bool exec) {
3307 // "exec" is passed in but not used. Creating the shared image for
3308 // the code cache doesn't have an SHM_X executable permission to check.
3309 assert(UseLargePages && UseSHM, "only for SHM large pages");
3310 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3311
3312 if (!is_size_aligned(bytes, os::large_page_size()) || alignment > os::large_page_size()) {
3313 return NULL; // Fallback to small pages.
3314 }
3315
3316 key_t key = IPC_PRIVATE;
3317 char *addr;
3318
3319 bool warn_on_failure = UseLargePages &&
3320 (!FLAG_IS_DEFAULT(UseLargePages) ||
3321 !FLAG_IS_DEFAULT(UseSHM) ||
3322 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3323 char msg[128];
3324
3325 // Create a large shared memory region to attach to based on size.
3326 // Currently, size is the total size of the heap
3327 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3328 if (shmid == -1) {
3329 // Possible reasons for shmget failure:
3330 // 1. shmmax is too small for Java heap.
3331 // > check shmmax value: cat /proc/sys/kernel/shmmax
3332 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3333 // 2. not enough large page memory.
3334 // > check available large pages: cat /proc/meminfo
3335 // > increase amount of large pages:
3336 // echo new_value > /proc/sys/vm/nr_hugepages
3337 // Note 1: different Linux may use different name for this property,
3338 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3339 // Note 2: it's possible there's enough physical memory available but
3340 // they are so fragmented after a long run that they can't
3341 // coalesce into large pages. Try to reserve large pages when
3342 // the system is still "fresh".
3343 if (warn_on_failure) {
3344 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3345 warning("%s", msg);
3346 }
3347 return NULL;
3348 }
3349
3350 // attach to the region
3351 addr = (char*)shmat(shmid, req_addr, 0);
3352 int err = errno;
3353
3354 // Remove shmid. If shmat() is successful, the actual shared memory segment
3355 // will be deleted when it's detached by shmdt() or when the process
3356 // terminates. If shmat() is not successful this will remove the shared
3357 // segment immediately.
3358 shmctl(shmid, IPC_RMID, NULL);
3359
3360 if ((intptr_t)addr == -1) {
3361 if (warn_on_failure) {
3362 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3363 warning("%s", msg);
3364 }
3365 return NULL;
3366 }
3367
3368 return addr;
3369 }
3370
3371 static void warn_on_large_pages_failure(char* req_addr, size_t bytes,
3372 int error) {
3373 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3374
3375 bool warn_on_failure = UseLargePages &&
3376 (!FLAG_IS_DEFAULT(UseLargePages) ||
3377 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3378 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3379
3380 if (warn_on_failure) {
3381 char msg[128];
3382 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3383 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3384 warning("%s", msg);
3385 }
3386 }
3387
3388 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes,
3389 char* req_addr,
3390 bool exec) {
3391 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3392 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3393 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3394
3395 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3396 char* addr = (char*)::mmap(req_addr, bytes, prot,
3397 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3398 -1, 0);
3399
3400 if (addr == MAP_FAILED) {
3401 warn_on_large_pages_failure(req_addr, bytes, errno);
3402 return NULL;
3403 }
3404
3405 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3406
3407 return addr;
3408 }
3409
3410 // Helper for os::Linux::reserve_memory_special_huge_tlbfs_mixed().
3411 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3412 // (req_addr != NULL) or with a given alignment.
3413 // - bytes shall be a multiple of alignment.
3414 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3415 // - alignment sets the alignment at which memory shall be allocated.
3416 // It must be a multiple of allocation granularity.
3417 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3418 // req_addr or NULL.
3419 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3420
3421 size_t extra_size = bytes;
3422 if (req_addr == NULL && alignment > 0) {
3423 extra_size += alignment;
3424 }
3425
3426 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3427 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3428 -1, 0);
3429 if (start == MAP_FAILED) {
3430 start = NULL;
3431 } else {
3432 if (req_addr != NULL) {
3433 if (start != req_addr) {
3434 ::munmap(start, extra_size);
3435 start = NULL;
3436 }
3437 } else {
3438 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3439 char* const end_aligned = start_aligned + bytes;
3440 char* const end = start + extra_size;
3441 if (start_aligned > start) {
3442 ::munmap(start, start_aligned - start);
3443 }
3444 if (end_aligned < end) {
3445 ::munmap(end_aligned, end - end_aligned);
3446 }
3447 start = start_aligned;
3448 }
3449 }
3450 return start;
3451
3452 }
3453
3454 // Reserve memory using mmap(MAP_HUGETLB).
3455 // - bytes shall be a multiple of alignment.
3456 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3457 // - alignment sets the alignment at which memory shall be allocated.
3458 // It must be a multiple of allocation granularity.
3459 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3460 // req_addr or NULL.
3461 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes,
3462 size_t alignment,
3463 char* req_addr,
3464 bool exec) {
3465 size_t large_page_size = os::large_page_size();
3466 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3467
3468 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3469 assert(is_size_aligned(bytes, alignment), "Must be");
3470
3471 // First reserve - but not commit - the address range in small pages.
3472 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3473
3474 if (start == NULL) {
3475 return NULL;
3476 }
3477
3478 assert(is_ptr_aligned(start, alignment), "Must be");
3479
3480 char* end = start + bytes;
3481
3482 // Find the regions of the allocated chunk that can be promoted to large pages.
3483 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3484 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3485
3486 size_t lp_bytes = lp_end - lp_start;
3487
3488 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3489
3490 if (lp_bytes == 0) {
3491 // The mapped region doesn't even span the start and the end of a large page.
3492 // Fall back to allocate a non-special area.
3493 ::munmap(start, end - start);
3494 return NULL;
3495 }
3496
3497 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3498
3499 void* result;
3500
3501 // Commit small-paged leading area.
3502 if (start != lp_start) {
3503 result = ::mmap(start, lp_start - start, prot,
3504 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3505 -1, 0);
3506 if (result == MAP_FAILED) {
3507 ::munmap(lp_start, end - lp_start);
3508 return NULL;
3509 }
3510 }
3511
3512 // Commit large-paged area.
3513 result = ::mmap(lp_start, lp_bytes, prot,
3514 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3515 -1, 0);
3516 if (result == MAP_FAILED) {
3517 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3518 // If the mmap above fails, the large pages region will be unmapped and we
3519 // have regions before and after with small pages. Release these regions.
3520 //
3521 // | mapped | unmapped | mapped |
3522 // ^ ^ ^ ^
3523 // start lp_start lp_end end
3524 //
3525 ::munmap(start, lp_start - start);
3526 ::munmap(lp_end, end - lp_end);
3527 return NULL;
3528 }
3529
3530 // Commit small-paged trailing area.
3531 if (lp_end != end) {
3532 result = ::mmap(lp_end, end - lp_end, prot,
3533 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3534 -1, 0);
3535 if (result == MAP_FAILED) {
3536 ::munmap(start, lp_end - start);
3537 return NULL;
3538 }
3539 }
3540
3541 return start;
3542 }
3543
3544 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes,
3545 size_t alignment,
3546 char* req_addr,
3547 bool exec) {
3548 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3549 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3550 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3551 assert(is_power_of_2(os::large_page_size()), "Must be");
3552 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3553
3554 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3555 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3556 } else {
3557 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3558 }
3559 }
3560
3561 char* os::reserve_memory_special(size_t bytes, size_t alignment,
3562 char* req_addr, bool exec) {
3563 assert(UseLargePages, "only for large pages");
3564
3565 char* addr;
3566 if (UseSHM) {
3567 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3568 } else {
3569 assert(UseHugeTLBFS, "must be");
3570 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3571 }
3572
3573 if (addr != NULL) {
3574 if (UseNUMAInterleaving) {
3575 numa_make_global(addr, bytes);
3576 }
3577
3578 // The memory is committed
3579 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3580 }
3581
3582 return addr;
3583 }
3584
3585 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3586 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3587 return shmdt(base) == 0;
3588 }
3589
3590 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3591 return pd_release_memory(base, bytes);
3592 }
3593
3594 bool os::release_memory_special(char* base, size_t bytes) {
3595 bool res;
3596 if (MemTracker::tracking_level() > NMT_minimal) {
3597 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3598 res = os::Linux::release_memory_special_impl(base, bytes);
3599 if (res) {
3600 tkr.record((address)base, bytes);
3601 }
3602
3603 } else {
3604 res = os::Linux::release_memory_special_impl(base, bytes);
3605 }
3606 return res;
3607 }
3608
3609 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3610 assert(UseLargePages, "only for large pages");
3611 bool res;
3612
3613 if (UseSHM) {
3614 res = os::Linux::release_memory_special_shm(base, bytes);
3615 } else {
3616 assert(UseHugeTLBFS, "must be");
3617 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3618 }
3619 return res;
3620 }
3621
3622 size_t os::large_page_size() {
3623 return _large_page_size;
3624 }
3625
3626 // With SysV SHM the entire memory region must be allocated as shared
3627 // memory.
3628 // HugeTLBFS allows application to commit large page memory on demand.
3629 // However, when committing memory with HugeTLBFS fails, the region
3630 // that was supposed to be committed will lose the old reservation
3631 // and allow other threads to steal that memory region. Because of this
3632 // behavior we can't commit HugeTLBFS memory.
3633 bool os::can_commit_large_page_memory() {
3634 return UseTransparentHugePages;
3635 }
3636
3637 bool os::can_execute_large_page_memory() {
3638 return UseTransparentHugePages || UseHugeTLBFS;
3639 }
3640
3641 // Reserve memory at an arbitrary address, only if that area is
3642 // available (and not reserved for something else).
3643
3644 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3645 const int max_tries = 10;
3646 char* base[max_tries];
3647 size_t size[max_tries];
3648 const size_t gap = 0x000000;
3649
3650 // Assert only that the size is a multiple of the page size, since
3651 // that's all that mmap requires, and since that's all we really know
3652 // about at this low abstraction level. If we need higher alignment,
3653 // we can either pass an alignment to this method or verify alignment
3654 // in one of the methods further up the call chain. See bug 5044738.
3655 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3656
3657 // Repeatedly allocate blocks until the block is allocated at the
3658 // right spot.
3659
3660 // Linux mmap allows caller to pass an address as hint; give it a try first,
3661 // if kernel honors the hint then we can return immediately.
3662 char * addr = anon_mmap(requested_addr, bytes, false);
3663 if (addr == requested_addr) {
3664 return requested_addr;
3665 }
3666
3667 if (addr != NULL) {
3668 // mmap() is successful but it fails to reserve at the requested address
3669 anon_munmap(addr, bytes);
3670 }
3671
3672 int i;
3673 for (i = 0; i < max_tries; ++i) {
3674 base[i] = reserve_memory(bytes);
3675
3676 if (base[i] != NULL) {
3677 // Is this the block we wanted?
3678 if (base[i] == requested_addr) {
3679 size[i] = bytes;
3680 break;
3681 }
3682
3683 // Does this overlap the block we wanted? Give back the overlapped
3684 // parts and try again.
3685
3686 ptrdiff_t top_overlap = requested_addr + (bytes + gap) - base[i];
3687 if (top_overlap >= 0 && (size_t)top_overlap < bytes) {
3688 unmap_memory(base[i], top_overlap);
3689 base[i] += top_overlap;
3690 size[i] = bytes - top_overlap;
3691 } else {
3692 ptrdiff_t bottom_overlap = base[i] + bytes - requested_addr;
3693 if (bottom_overlap >= 0 && (size_t)bottom_overlap < bytes) {
3694 unmap_memory(requested_addr, bottom_overlap);
3695 size[i] = bytes - bottom_overlap;
3696 } else {
3697 size[i] = bytes;
3698 }
3699 }
3700 }
3701 }
3702
3703 // Give back the unused reserved pieces.
3704
3705 for (int j = 0; j < i; ++j) {
3706 if (base[j] != NULL) {
3707 unmap_memory(base[j], size[j]);
3708 }
3709 }
3710
3711 if (i < max_tries) {
3712 return requested_addr;
3713 } else {
3714 return NULL;
3715 }
3716 }
3717
3718 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3719 return ::read(fd, buf, nBytes);
3720 }
3721
3722 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
3723 return ::pread(fd, buf, nBytes, offset);
3724 }
3725
3726 // Short sleep, direct OS call.
3727 //
3728 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
3729 // sched_yield(2) will actually give up the CPU:
3730 //
3731 // * Alone on this pariticular CPU, keeps running.
3732 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
3733 // (pre 2.6.39).
3734 //
3735 // So calling this with 0 is an alternative.
3736 //
3737 void os::naked_short_sleep(jlong ms) {
3738 struct timespec req;
3739
3740 assert(ms < 1000, "Un-interruptable sleep, short time use only");
3741 req.tv_sec = 0;
3742 if (ms > 0) {
3743 req.tv_nsec = (ms % 1000) * 1000000;
3744 } else {
3745 req.tv_nsec = 1;
3746 }
3747
3748 nanosleep(&req, NULL);
3749
3750 return;
3751 }
3752
3753 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3754 void os::infinite_sleep() {
3755 while (true) { // sleep forever ...
3756 ::sleep(100); // ... 100 seconds at a time
3757 }
3758 }
3759
3760 // Used to convert frequent JVM_Yield() to nops
3761 bool os::dont_yield() {
3762 return DontYieldALot;
3763 }
3764
3765 void os::naked_yield() {
3766 sched_yield();
3767 }
3768
3769 ////////////////////////////////////////////////////////////////////////////////
3770 // thread priority support
3771
3772 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3773 // only supports dynamic priority, static priority must be zero. For real-time
3774 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3775 // However, for large multi-threaded applications, SCHED_RR is not only slower
3776 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3777 // of 5 runs - Sep 2005).
3778 //
3779 // The following code actually changes the niceness of kernel-thread/LWP. It
3780 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3781 // not the entire user process, and user level threads are 1:1 mapped to kernel
3782 // threads. It has always been the case, but could change in the future. For
3783 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3784 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3785
3786 int os::java_to_os_priority[CriticalPriority + 1] = {
3787 19, // 0 Entry should never be used
3788
3789 4, // 1 MinPriority
3790 3, // 2
3791 2, // 3
3792
3793 1, // 4
3794 0, // 5 NormPriority
3795 -1, // 6
3796
3797 -2, // 7
3798 -3, // 8
3799 -4, // 9 NearMaxPriority
3800
3801 -5, // 10 MaxPriority
3802
3803 -5 // 11 CriticalPriority
3804 };
3805
3806 static int prio_init() {
3807 if (ThreadPriorityPolicy == 1) {
3808 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3809 // if effective uid is not root. Perhaps, a more elegant way of doing
3810 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3811 if (geteuid() != 0) {
3812 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3813 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3814 }
3815 ThreadPriorityPolicy = 0;
3816 }
3817 }
3818 if (UseCriticalJavaThreadPriority) {
3819 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3820 }
3821 return 0;
3822 }
3823
3824 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3825 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) return OS_OK;
3826
3827 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3828 return (ret == 0) ? OS_OK : OS_ERR;
3829 }
3830
3831 OSReturn os::get_native_priority(const Thread* const thread,
3832 int *priority_ptr) {
3833 if (!UseThreadPriorities || ThreadPriorityPolicy == 0) {
3834 *priority_ptr = java_to_os_priority[NormPriority];
3835 return OS_OK;
3836 }
3837
3838 errno = 0;
3839 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3840 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3841 }
3842
3843 // Hint to the underlying OS that a task switch would not be good.
3844 // Void return because it's a hint and can fail.
3845 void os::hint_no_preempt() {}
3846
3847 ////////////////////////////////////////////////////////////////////////////////
3848 // suspend/resume support
3849
3850 // the low-level signal-based suspend/resume support is a remnant from the
3851 // old VM-suspension that used to be for java-suspension, safepoints etc,
3852 // within hotspot. Now there is a single use-case for this:
3853 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3854 // that runs in the watcher thread.
3855 // The remaining code is greatly simplified from the more general suspension
3856 // code that used to be used.
3857 //
3858 // The protocol is quite simple:
3859 // - suspend:
3860 // - sends a signal to the target thread
3861 // - polls the suspend state of the osthread using a yield loop
3862 // - target thread signal handler (SR_handler) sets suspend state
3863 // and blocks in sigsuspend until continued
3864 // - resume:
3865 // - sets target osthread state to continue
3866 // - sends signal to end the sigsuspend loop in the SR_handler
3867 //
3868 // Note that the SR_lock plays no role in this suspend/resume protocol.
3869
3870 static void resume_clear_context(OSThread *osthread) {
3871 osthread->set_ucontext(NULL);
3872 osthread->set_siginfo(NULL);
3873 }
3874
3875 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo,
3876 ucontext_t* context) {
3877 osthread->set_ucontext(context);
3878 osthread->set_siginfo(siginfo);
3879 }
3880
3881 // Handler function invoked when a thread's execution is suspended or
3882 // resumed. We have to be careful that only async-safe functions are
3883 // called here (Note: most pthread functions are not async safe and
3884 // should be avoided.)
3885 //
3886 // Note: sigwait() is a more natural fit than sigsuspend() from an
3887 // interface point of view, but sigwait() prevents the signal hander
3888 // from being run. libpthread would get very confused by not having
3889 // its signal handlers run and prevents sigwait()'s use with the
3890 // mutex granting granting signal.
3891 //
3892 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
3893 //
3894 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3895 // Save and restore errno to avoid confusing native code with EINTR
3896 // after sigsuspend.
3897 int old_errno = errno;
3898
3899 Thread* thread = Thread::current();
3900 OSThread* osthread = thread->osthread();
3901 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
3902
3903 os::SuspendResume::State current = osthread->sr.state();
3904 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
3905 suspend_save_context(osthread, siginfo, context);
3906
3907 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
3908 os::SuspendResume::State state = osthread->sr.suspended();
3909 if (state == os::SuspendResume::SR_SUSPENDED) {
3910 sigset_t suspend_set; // signals for sigsuspend()
3911
3912 // get current set of blocked signals and unblock resume signal
3913 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3914 sigdelset(&suspend_set, SR_signum);
3915
3916 sr_semaphore.signal();
3917 // wait here until we are resumed
3918 while (1) {
3919 sigsuspend(&suspend_set);
3920
3921 os::SuspendResume::State result = osthread->sr.running();
3922 if (result == os::SuspendResume::SR_RUNNING) {
3923 sr_semaphore.signal();
3924 break;
3925 }
3926 }
3927
3928 } else if (state == os::SuspendResume::SR_RUNNING) {
3929 // request was cancelled, continue
3930 } else {
3931 ShouldNotReachHere();
3932 }
3933
3934 resume_clear_context(osthread);
3935 } else if (current == os::SuspendResume::SR_RUNNING) {
3936 // request was cancelled, continue
3937 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
3938 // ignore
3939 } else {
3940 // ignore
3941 }
3942
3943 errno = old_errno;
3944 }
3945
3946 static int SR_initialize() {
3947 struct sigaction act;
3948 char *s;
3949
3950 // Get signal number to use for suspend/resume
3951 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3952 int sig = ::strtol(s, 0, 10);
3953 if (sig > MAX2(SIGSEGV, SIGBUS) && // See 4355769.
3954 sig < NSIG) { // Must be legal signal and fit into sigflags[].
3955 SR_signum = sig;
3956 } else {
3957 warning("You set _JAVA_SR_SIGNUM=%d. It must be in range [%d, %d]. Using %d instead.",
3958 sig, MAX2(SIGSEGV, SIGBUS)+1, NSIG-1, SR_signum);
3959 }
3960 }
3961
3962 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3963 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3964
3965 sigemptyset(&SR_sigset);
3966 sigaddset(&SR_sigset, SR_signum);
3967
3968 // Set up signal handler for suspend/resume
3969 act.sa_flags = SA_RESTART|SA_SIGINFO;
3970 act.sa_handler = (void (*)(int)) SR_handler;
3971
3972 // SR_signum is blocked by default.
3973 // 4528190 - We also need to block pthread restart signal (32 on all
3974 // supported Linux platforms). Note that LinuxThreads need to block
3975 // this signal for all threads to work properly. So we don't have
3976 // to use hard-coded signal number when setting up the mask.
3977 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3978
3979 if (sigaction(SR_signum, &act, 0) == -1) {
3980 return -1;
3981 }
3982
3983 // Save signal flag
3984 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3985 return 0;
3986 }
3987
3988 static int sr_notify(OSThread* osthread) {
3989 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3990 assert_status(status == 0, status, "pthread_kill");
3991 return status;
3992 }
3993
3994 // "Randomly" selected value for how long we want to spin
3995 // before bailing out on suspending a thread, also how often
3996 // we send a signal to a thread we want to resume
3997 static const int RANDOMLY_LARGE_INTEGER = 1000000;
3998 static const int RANDOMLY_LARGE_INTEGER2 = 100;
3999
4000 // returns true on success and false on error - really an error is fatal
4001 // but this seems the normal response to library errors
4002 static bool do_suspend(OSThread* osthread) {
4003 assert(osthread->sr.is_running(), "thread should be running");
4004 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4005
4006 // mark as suspended and send signal
4007 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4008 // failed to switch, state wasn't running?
4009 ShouldNotReachHere();
4010 return false;
4011 }
4012
4013 if (sr_notify(osthread) != 0) {
4014 ShouldNotReachHere();
4015 }
4016
4017 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4018 while (true) {
4019 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4020 break;
4021 } else {
4022 // timeout
4023 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4024 if (cancelled == os::SuspendResume::SR_RUNNING) {
4025 return false;
4026 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4027 // make sure that we consume the signal on the semaphore as well
4028 sr_semaphore.wait();
4029 break;
4030 } else {
4031 ShouldNotReachHere();
4032 return false;
4033 }
4034 }
4035 }
4036
4037 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4038 return true;
4039 }
4040
4041 static void do_resume(OSThread* osthread) {
4042 assert(osthread->sr.is_suspended(), "thread should be suspended");
4043 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4044
4045 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4046 // failed to switch to WAKEUP_REQUEST
4047 ShouldNotReachHere();
4048 return;
4049 }
4050
4051 while (true) {
4052 if (sr_notify(osthread) == 0) {
4053 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4054 if (osthread->sr.is_running()) {
4055 return;
4056 }
4057 }
4058 } else {
4059 ShouldNotReachHere();
4060 }
4061 }
4062
4063 guarantee(osthread->sr.is_running(), "Must be running!");
4064 }
4065
4066 ///////////////////////////////////////////////////////////////////////////////////
4067 // signal handling (except suspend/resume)
4068
4069 // This routine may be used by user applications as a "hook" to catch signals.
4070 // The user-defined signal handler must pass unrecognized signals to this
4071 // routine, and if it returns true (non-zero), then the signal handler must
4072 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4073 // routine will never retun false (zero), but instead will execute a VM panic
4074 // routine kill the process.
4075 //
4076 // If this routine returns false, it is OK to call it again. This allows
4077 // the user-defined signal handler to perform checks either before or after
4078 // the VM performs its own checks. Naturally, the user code would be making
4079 // a serious error if it tried to handle an exception (such as a null check
4080 // or breakpoint) that the VM was generating for its own correct operation.
4081 //
4082 // This routine may recognize any of the following kinds of signals:
4083 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4084 // It should be consulted by handlers for any of those signals.
4085 //
4086 // The caller of this routine must pass in the three arguments supplied
4087 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4088 // field of the structure passed to sigaction(). This routine assumes that
4089 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4090 //
4091 // Note that the VM will print warnings if it detects conflicting signal
4092 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4093 //
4094 extern "C" JNIEXPORT int JVM_handle_linux_signal(int signo,
4095 siginfo_t* siginfo,
4096 void* ucontext,
4097 int abort_if_unrecognized);
4098
4099 void signalHandler(int sig, siginfo_t* info, void* uc) {
4100 assert(info != NULL && uc != NULL, "it must be old kernel");
4101 int orig_errno = errno; // Preserve errno value over signal handler.
4102 JVM_handle_linux_signal(sig, info, uc, true);
4103 errno = orig_errno;
4104 }
4105
4106
4107 // This boolean allows users to forward their own non-matching signals
4108 // to JVM_handle_linux_signal, harmlessly.
4109 bool os::Linux::signal_handlers_are_installed = false;
4110
4111 // For signal-chaining
4112 struct sigaction sigact[NSIG];
4113 uint64_t sigs = 0;
4114 #if (64 < NSIG-1)
4115 #error "Not all signals can be encoded in sigs. Adapt its type!"
4116 #endif
4117 bool os::Linux::libjsig_is_loaded = false;
4118 typedef struct sigaction *(*get_signal_t)(int);
4119 get_signal_t os::Linux::get_signal_action = NULL;
4120
4121 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4122 struct sigaction *actp = NULL;
4123
4124 if (libjsig_is_loaded) {
4125 // Retrieve the old signal handler from libjsig
4126 actp = (*get_signal_action)(sig);
4127 }
4128 if (actp == NULL) {
4129 // Retrieve the preinstalled signal handler from jvm
4130 actp = get_preinstalled_handler(sig);
4131 }
4132
4133 return actp;
4134 }
4135
4136 static bool call_chained_handler(struct sigaction *actp, int sig,
4137 siginfo_t *siginfo, void *context) {
4138 // Call the old signal handler
4139 if (actp->sa_handler == SIG_DFL) {
4140 // It's more reasonable to let jvm treat it as an unexpected exception
4141 // instead of taking the default action.
4142 return false;
4143 } else if (actp->sa_handler != SIG_IGN) {
4144 if ((actp->sa_flags & SA_NODEFER) == 0) {
4145 // automaticlly block the signal
4146 sigaddset(&(actp->sa_mask), sig);
4147 }
4148
4149 sa_handler_t hand = NULL;
4150 sa_sigaction_t sa = NULL;
4151 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4152 // retrieve the chained handler
4153 if (siginfo_flag_set) {
4154 sa = actp->sa_sigaction;
4155 } else {
4156 hand = actp->sa_handler;
4157 }
4158
4159 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4160 actp->sa_handler = SIG_DFL;
4161 }
4162
4163 // try to honor the signal mask
4164 sigset_t oset;
4165 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4166
4167 // call into the chained handler
4168 if (siginfo_flag_set) {
4169 (*sa)(sig, siginfo, context);
4170 } else {
4171 (*hand)(sig);
4172 }
4173
4174 // restore the signal mask
4175 pthread_sigmask(SIG_SETMASK, &oset, 0);
4176 }
4177 // Tell jvm's signal handler the signal is taken care of.
4178 return true;
4179 }
4180
4181 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4182 bool chained = false;
4183 // signal-chaining
4184 if (UseSignalChaining) {
4185 struct sigaction *actp = get_chained_signal_action(sig);
4186 if (actp != NULL) {
4187 chained = call_chained_handler(actp, sig, siginfo, context);
4188 }
4189 }
4190 return chained;
4191 }
4192
4193 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4194 if ((((uint64_t)1 << (sig-1)) & sigs) != 0) {
4195 return &sigact[sig];
4196 }
4197 return NULL;
4198 }
4199
4200 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4201 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4202 sigact[sig] = oldAct;
4203 sigs |= (uint64_t)1 << (sig-1);
4204 }
4205
4206 // for diagnostic
4207 int sigflags[NSIG];
4208
4209 int os::Linux::get_our_sigflags(int sig) {
4210 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4211 return sigflags[sig];
4212 }
4213
4214 void os::Linux::set_our_sigflags(int sig, int flags) {
4215 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4216 if (sig > 0 && sig < NSIG) {
4217 sigflags[sig] = flags;
4218 }
4219 }
4220
4221 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4222 // Check for overwrite.
4223 struct sigaction oldAct;
4224 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4225
4226 void* oldhand = oldAct.sa_sigaction
4227 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4228 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4229 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4230 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4231 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4232 if (AllowUserSignalHandlers || !set_installed) {
4233 // Do not overwrite; user takes responsibility to forward to us.
4234 return;
4235 } else if (UseSignalChaining) {
4236 // save the old handler in jvm
4237 save_preinstalled_handler(sig, oldAct);
4238 // libjsig also interposes the sigaction() call below and saves the
4239 // old sigaction on it own.
4240 } else {
4241 fatal("Encountered unexpected pre-existing sigaction handler "
4242 "%#lx for signal %d.", (long)oldhand, sig);
4243 }
4244 }
4245
4246 struct sigaction sigAct;
4247 sigfillset(&(sigAct.sa_mask));
4248 sigAct.sa_handler = SIG_DFL;
4249 if (!set_installed) {
4250 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4251 } else {
4252 sigAct.sa_sigaction = signalHandler;
4253 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4254 }
4255 // Save flags, which are set by ours
4256 assert(sig > 0 && sig < NSIG, "vm signal out of expected range");
4257 sigflags[sig] = sigAct.sa_flags;
4258
4259 int ret = sigaction(sig, &sigAct, &oldAct);
4260 assert(ret == 0, "check");
4261
4262 void* oldhand2 = oldAct.sa_sigaction
4263 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4264 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4265 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4266 }
4267
4268 // install signal handlers for signals that HotSpot needs to
4269 // handle in order to support Java-level exception handling.
4270
4271 void os::Linux::install_signal_handlers() {
4272 if (!signal_handlers_are_installed) {
4273 signal_handlers_are_installed = true;
4274
4275 // signal-chaining
4276 typedef void (*signal_setting_t)();
4277 signal_setting_t begin_signal_setting = NULL;
4278 signal_setting_t end_signal_setting = NULL;
4279 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4280 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4281 if (begin_signal_setting != NULL) {
4282 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4283 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4284 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4285 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4286 libjsig_is_loaded = true;
4287 assert(UseSignalChaining, "should enable signal-chaining");
4288 }
4289 if (libjsig_is_loaded) {
4290 // Tell libjsig jvm is setting signal handlers
4291 (*begin_signal_setting)();
4292 }
4293
4294 set_signal_handler(SIGSEGV, true);
4295 set_signal_handler(SIGPIPE, true);
4296 set_signal_handler(SIGBUS, true);
4297 set_signal_handler(SIGILL, true);
4298 set_signal_handler(SIGFPE, true);
4299 #if defined(PPC64)
4300 set_signal_handler(SIGTRAP, true);
4301 #endif
4302 set_signal_handler(SIGXFSZ, true);
4303
4304 if (libjsig_is_loaded) {
4305 // Tell libjsig jvm finishes setting signal handlers
4306 (*end_signal_setting)();
4307 }
4308
4309 // We don't activate signal checker if libjsig is in place, we trust ourselves
4310 // and if UserSignalHandler is installed all bets are off.
4311 // Log that signal checking is off only if -verbose:jni is specified.
4312 if (CheckJNICalls) {
4313 if (libjsig_is_loaded) {
4314 if (PrintJNIResolving) {
4315 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4316 }
4317 check_signals = false;
4318 }
4319 if (AllowUserSignalHandlers) {
4320 if (PrintJNIResolving) {
4321 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4322 }
4323 check_signals = false;
4324 }
4325 }
4326 }
4327 }
4328
4329 // This is the fastest way to get thread cpu time on Linux.
4330 // Returns cpu time (user+sys) for any thread, not only for current.
4331 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4332 // It might work on 2.6.10+ with a special kernel/glibc patch.
4333 // For reference, please, see IEEE Std 1003.1-2004:
4334 // http://www.unix.org/single_unix_specification
4335
4336 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4337 struct timespec tp;
4338 int rc = os::Linux::clock_gettime(clockid, &tp);
4339 assert(rc == 0, "clock_gettime is expected to return 0 code");
4340
4341 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4342 }
4343
4344 /////
4345 // glibc on Linux platform uses non-documented flag
4346 // to indicate, that some special sort of signal
4347 // trampoline is used.
4348 // We will never set this flag, and we should
4349 // ignore this flag in our diagnostic
4350 #ifdef SIGNIFICANT_SIGNAL_MASK
4351 #undef SIGNIFICANT_SIGNAL_MASK
4352 #endif
4353 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4354
4355 static const char* get_signal_handler_name(address handler,
4356 char* buf, int buflen) {
4357 int offset = 0;
4358 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4359 if (found) {
4360 // skip directory names
4361 const char *p1, *p2;
4362 p1 = buf;
4363 size_t len = strlen(os::file_separator());
4364 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4365 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4366 } else {
4367 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4368 }
4369 return buf;
4370 }
4371
4372 static void print_signal_handler(outputStream* st, int sig,
4373 char* buf, size_t buflen) {
4374 struct sigaction sa;
4375
4376 sigaction(sig, NULL, &sa);
4377
4378 // See comment for SIGNIFICANT_SIGNAL_MASK define
4379 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4380
4381 st->print("%s: ", os::exception_name(sig, buf, buflen));
4382
4383 address handler = (sa.sa_flags & SA_SIGINFO)
4384 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4385 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4386
4387 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4388 st->print("SIG_DFL");
4389 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4390 st->print("SIG_IGN");
4391 } else {
4392 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4393 }
4394
4395 st->print(", sa_mask[0]=");
4396 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4397
4398 address rh = VMError::get_resetted_sighandler(sig);
4399 // May be, handler was resetted by VMError?
4400 if (rh != NULL) {
4401 handler = rh;
4402 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4403 }
4404
4405 st->print(", sa_flags=");
4406 os::Posix::print_sa_flags(st, sa.sa_flags);
4407
4408 // Check: is it our handler?
4409 if (handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4410 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4411 // It is our signal handler
4412 // check for flags, reset system-used one!
4413 if ((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4414 st->print(
4415 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4416 os::Linux::get_our_sigflags(sig));
4417 }
4418 }
4419 st->cr();
4420 }
4421
4422
4423 #define DO_SIGNAL_CHECK(sig) \
4424 do { \
4425 if (!sigismember(&check_signal_done, sig)) { \
4426 os::Linux::check_signal_handler(sig); \
4427 } \
4428 } while (0)
4429
4430 // This method is a periodic task to check for misbehaving JNI applications
4431 // under CheckJNI, we can add any periodic checks here
4432
4433 void os::run_periodic_checks() {
4434 if (check_signals == false) return;
4435
4436 // SEGV and BUS if overridden could potentially prevent
4437 // generation of hs*.log in the event of a crash, debugging
4438 // such a case can be very challenging, so we absolutely
4439 // check the following for a good measure:
4440 DO_SIGNAL_CHECK(SIGSEGV);
4441 DO_SIGNAL_CHECK(SIGILL);
4442 DO_SIGNAL_CHECK(SIGFPE);
4443 DO_SIGNAL_CHECK(SIGBUS);
4444 DO_SIGNAL_CHECK(SIGPIPE);
4445 DO_SIGNAL_CHECK(SIGXFSZ);
4446 #if defined(PPC64)
4447 DO_SIGNAL_CHECK(SIGTRAP);
4448 #endif
4449
4450 // ReduceSignalUsage allows the user to override these handlers
4451 // see comments at the very top and jvm_solaris.h
4452 if (!ReduceSignalUsage) {
4453 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4454 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4455 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4456 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4457 }
4458
4459 DO_SIGNAL_CHECK(SR_signum);
4460 }
4461
4462 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4463
4464 static os_sigaction_t os_sigaction = NULL;
4465
4466 void os::Linux::check_signal_handler(int sig) {
4467 char buf[O_BUFLEN];
4468 address jvmHandler = NULL;
4469
4470
4471 struct sigaction act;
4472 if (os_sigaction == NULL) {
4473 // only trust the default sigaction, in case it has been interposed
4474 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4475 if (os_sigaction == NULL) return;
4476 }
4477
4478 os_sigaction(sig, (struct sigaction*)NULL, &act);
4479
4480
4481 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4482
4483 address thisHandler = (act.sa_flags & SA_SIGINFO)
4484 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4485 : CAST_FROM_FN_PTR(address, act.sa_handler);
4486
4487
4488 switch (sig) {
4489 case SIGSEGV:
4490 case SIGBUS:
4491 case SIGFPE:
4492 case SIGPIPE:
4493 case SIGILL:
4494 case SIGXFSZ:
4495 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4496 break;
4497
4498 case SHUTDOWN1_SIGNAL:
4499 case SHUTDOWN2_SIGNAL:
4500 case SHUTDOWN3_SIGNAL:
4501 case BREAK_SIGNAL:
4502 jvmHandler = (address)user_handler();
4503 break;
4504
4505 default:
4506 if (sig == SR_signum) {
4507 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4508 } else {
4509 return;
4510 }
4511 break;
4512 }
4513
4514 if (thisHandler != jvmHandler) {
4515 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4516 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4517 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4518 // No need to check this sig any longer
4519 sigaddset(&check_signal_done, sig);
4520 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4521 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
4522 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
4523 exception_name(sig, buf, O_BUFLEN));
4524 }
4525 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4526 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4527 tty->print("expected:");
4528 os::Posix::print_sa_flags(tty, os::Linux::get_our_sigflags(sig));
4529 tty->cr();
4530 tty->print(" found:");
4531 os::Posix::print_sa_flags(tty, act.sa_flags);
4532 tty->cr();
4533 // No need to check this sig any longer
4534 sigaddset(&check_signal_done, sig);
4535 }
4536
4537 // Dump all the signal
4538 if (sigismember(&check_signal_done, sig)) {
4539 print_signal_handlers(tty, buf, O_BUFLEN);
4540 }
4541 }
4542
4543 extern void report_error(char* file_name, int line_no, char* title,
4544 char* format, ...);
4545
4546 // this is called _before_ the most of global arguments have been parsed
4547 void os::init(void) {
4548 char dummy; // used to get a guess on initial stack address
4549 // first_hrtime = gethrtime();
4550
4551 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4552
4553 init_random(1234567);
4554
4555 ThreadCritical::initialize();
4556
4557 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4558 if (Linux::page_size() == -1) {
4559 fatal("os_linux.cpp: os::init: sysconf failed (%s)",
4560 strerror(errno));
4561 }
4562 init_page_sizes((size_t) Linux::page_size());
4563
4564 Linux::initialize_system_info();
4565
4566 // main_thread points to the aboriginal thread
4567 Linux::_main_thread = pthread_self();
4568
4569 Linux::clock_init();
4570 initial_time_count = javaTimeNanos();
4571
4572 // pthread_condattr initialization for monotonic clock
4573 int status;
4574 pthread_condattr_t* _condattr = os::Linux::condAttr();
4575 if ((status = pthread_condattr_init(_condattr)) != 0) {
4576 fatal("pthread_condattr_init: %s", strerror(status));
4577 }
4578 // Only set the clock if CLOCK_MONOTONIC is available
4579 if (os::supports_monotonic_clock()) {
4580 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
4581 if (status == EINVAL) {
4582 warning("Unable to use monotonic clock with relative timed-waits" \
4583 " - changes to the time-of-day clock may have adverse affects");
4584 } else {
4585 fatal("pthread_condattr_setclock: %s", strerror(status));
4586 }
4587 }
4588 }
4589 // else it defaults to CLOCK_REALTIME
4590
4591 // retrieve entry point for pthread_setname_np
4592 Linux::_pthread_setname_np =
4593 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
4594
4595 }
4596
4597 // To install functions for atexit system call
4598 extern "C" {
4599 static void perfMemory_exit_helper() {
4600 perfMemory_exit();
4601 }
4602 }
4603
4604 // this is called _after_ the global arguments have been parsed
4605 jint os::init_2(void) {
4606 Linux::fast_thread_clock_init();
4607
4608 // Allocate a single page and mark it as readable for safepoint polling
4609 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4610 guarantee(polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page");
4611
4612 os::set_polling_page(polling_page);
4613
4614 #ifndef PRODUCT
4615 if (Verbose && PrintMiscellaneous) {
4616 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n",
4617 (intptr_t)polling_page);
4618 }
4619 #endif
4620
4621 if (!UseMembar) {
4622 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4623 guarantee(mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
4624 os::set_memory_serialize_page(mem_serialize_page);
4625
4626 #ifndef PRODUCT
4627 if (Verbose && PrintMiscellaneous) {
4628 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n",
4629 (intptr_t)mem_serialize_page);
4630 }
4631 #endif
4632 }
4633
4634 // initialize suspend/resume support - must do this before signal_sets_init()
4635 if (SR_initialize() != 0) {
4636 perror("SR_initialize failed");
4637 return JNI_ERR;
4638 }
4639
4640 Linux::signal_sets_init();
4641 Linux::install_signal_handlers();
4642
4643 // Check minimum allowable stack size for thread creation and to initialize
4644 // the java system classes, including StackOverflowError - depends on page
4645 // size. Add a page for compiler2 recursion in main thread.
4646 // Add in 2*BytesPerWord times page size to account for VM stack during
4647 // class initialization depending on 32 or 64 bit VM.
4648 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4649 JavaThread::stack_guard_zone_size() +
4650 JavaThread::stack_shadow_zone_size() +
4651 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
4652
4653 size_t threadStackSizeInBytes = ThreadStackSize * K;
4654 if (threadStackSizeInBytes != 0 &&
4655 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4656 tty->print_cr("\nThe stack size specified is too small, "
4657 "Specify at least " SIZE_FORMAT "k",
4658 os::Linux::min_stack_allowed/ K);
4659 return JNI_ERR;
4660 }
4661
4662 // Make the stack size a multiple of the page size so that
4663 // the yellow/red zones can be guarded.
4664 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4665 vm_page_size()));
4666
4667 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4668
4669 #if defined(IA32)
4670 workaround_expand_exec_shield_cs_limit();
4671 #endif
4672
4673 Linux::libpthread_init();
4674 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4675 tty->print_cr("[HotSpot is running with %s, %s]\n",
4676 Linux::glibc_version(), Linux::libpthread_version());
4677 }
4678
4679 if (UseNUMA) {
4680 if (!Linux::libnuma_init()) {
4681 UseNUMA = false;
4682 } else {
4683 if ((Linux::numa_max_node() < 1)) {
4684 // There's only one node(they start from 0), disable NUMA.
4685 UseNUMA = false;
4686 }
4687 }
4688 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
4689 // we can make the adaptive lgrp chunk resizing work. If the user specified
4690 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
4691 // disable adaptive resizing.
4692 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
4693 if (FLAG_IS_DEFAULT(UseNUMA)) {
4694 UseNUMA = false;
4695 } else {
4696 if (FLAG_IS_DEFAULT(UseLargePages) &&
4697 FLAG_IS_DEFAULT(UseSHM) &&
4698 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
4699 UseLargePages = false;
4700 } else if (UseAdaptiveSizePolicy || UseAdaptiveNUMAChunkSizing) {
4701 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing (-XX:-UseAdaptiveSizePolicy -XX:-UseAdaptiveNUMAChunkSizing)");
4702 UseAdaptiveSizePolicy = false;
4703 UseAdaptiveNUMAChunkSizing = false;
4704 }
4705 }
4706 }
4707 if (!UseNUMA && ForceNUMA) {
4708 UseNUMA = true;
4709 }
4710 }
4711
4712 if (MaxFDLimit) {
4713 // set the number of file descriptors to max. print out error
4714 // if getrlimit/setrlimit fails but continue regardless.
4715 struct rlimit nbr_files;
4716 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4717 if (status != 0) {
4718 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4719 perror("os::init_2 getrlimit failed");
4720 }
4721 } else {
4722 nbr_files.rlim_cur = nbr_files.rlim_max;
4723 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4724 if (status != 0) {
4725 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4726 perror("os::init_2 setrlimit failed");
4727 }
4728 }
4729 }
4730 }
4731
4732 // Initialize lock used to serialize thread creation (see os::create_thread)
4733 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4734
4735 // at-exit methods are called in the reverse order of their registration.
4736 // atexit functions are called on return from main or as a result of a
4737 // call to exit(3C). There can be only 32 of these functions registered
4738 // and atexit() does not set errno.
4739
4740 if (PerfAllowAtExitRegistration) {
4741 // only register atexit functions if PerfAllowAtExitRegistration is set.
4742 // atexit functions can be delayed until process exit time, which
4743 // can be problematic for embedded VM situations. Embedded VMs should
4744 // call DestroyJavaVM() to assure that VM resources are released.
4745
4746 // note: perfMemory_exit_helper atexit function may be removed in
4747 // the future if the appropriate cleanup code can be added to the
4748 // VM_Exit VMOperation's doit method.
4749 if (atexit(perfMemory_exit_helper) != 0) {
4750 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
4751 }
4752 }
4753
4754 // initialize thread priority policy
4755 prio_init();
4756
4757 return JNI_OK;
4758 }
4759
4760 // Mark the polling page as unreadable
4761 void os::make_polling_page_unreadable(void) {
4762 if (!guard_memory((char*)_polling_page, Linux::page_size())) {
4763 fatal("Could not disable polling page");
4764 }
4765 }
4766
4767 // Mark the polling page as readable
4768 void os::make_polling_page_readable(void) {
4769 if (!linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4770 fatal("Could not enable polling page");
4771 }
4772 }
4773
4774 // Get the current number of available processors for this process.
4775 // This value can change at any time during a process's lifetime.
4776 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
4777 // If it appears there may be more than 1024 processors then we do a
4778 // dynamic check - see 6515172 for details.
4779 // If anything goes wrong we fallback to returning the number of online
4780 // processors - which can be greater than the number available to the process.
4781 int os::active_processor_count() {
4782 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
4783 cpu_set_t* cpus_p = &cpus;
4784 int cpus_size = sizeof(cpu_set_t);
4785
4786 int configured_cpus = processor_count(); // upper bound on available cpus
4787 int cpu_count = 0;
4788
4789 // To enable easy testing of the dynamic path on different platforms we leave
4790 // in the diagnostic flag UseNewCode, for non-product builds
4791 if (configured_cpus >= CPU_SETSIZE NOT_PRODUCT(|| UseNewCode)) {
4792 // kernel may use a mask bigger than cpu_set_t
4793 log_trace(os)("active_processor_count: using dynamic path - configured processors: %d",
4794 configured_cpus);
4795 cpus_p = CPU_ALLOC(configured_cpus);
4796 if (cpus_p != NULL) {
4797 cpus_size = CPU_ALLOC_SIZE(configured_cpus);
4798 // zero it just to be safe
4799 CPU_ZERO_S(cpus_size, cpus_p);
4800 }
4801 else {
4802 // failed to allocate so fallback to online cpus
4803 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4804 log_trace(os)("active_processor_count: "
4805 "CPU_ALLOC failed (%s) - using "
4806 "online processor count: %d",
4807 strerror(errno), online_cpus);
4808 return online_cpus;
4809 }
4810 }
4811 else {
4812 log_trace(os)("active_processor_count: using static path - configured processors: %d",
4813 configured_cpus);
4814 }
4815
4816 // pid 0 means the current thread - which we have to assume represents the process
4817 if (sched_getaffinity(0, cpus_size, cpus_p) == 0) {
4818 if (cpus_p != &cpus) {
4819 cpu_count = CPU_COUNT_S(cpus_size, cpus_p);
4820 }
4821 else {
4822 cpu_count = CPU_COUNT(cpus_p);
4823 }
4824 log_trace(os)("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
4825 }
4826 else {
4827 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
4828 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
4829 "which may exceed available processors", strerror(errno), cpu_count);
4830 }
4831
4832 if (cpus_p != &cpus) {
4833 CPU_FREE(cpus_p);
4834 }
4835
4836 assert(cpu_count > 0 && cpu_count <= processor_count(), "sanity check");
4837 return cpu_count;
4838 }
4839
4840 void os::set_native_thread_name(const char *name) {
4841 if (Linux::_pthread_setname_np) {
4842 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
4843 snprintf(buf, sizeof(buf), "%s", name);
4844 buf[sizeof(buf) - 1] = '\0';
4845 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
4846 // ERANGE should not happen; all other errors should just be ignored.
4847 assert(rc != ERANGE, "pthread_setname_np failed");
4848 }
4849 }
4850
4851 bool os::distribute_processes(uint length, uint* distribution) {
4852 // Not yet implemented.
4853 return false;
4854 }
4855
4856 bool os::bind_to_processor(uint processor_id) {
4857 // Not yet implemented.
4858 return false;
4859 }
4860
4861 ///
4862
4863 void os::SuspendedThreadTask::internal_do_task() {
4864 if (do_suspend(_thread->osthread())) {
4865 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
4866 do_task(context);
4867 do_resume(_thread->osthread());
4868 }
4869 }
4870
4871 class PcFetcher : public os::SuspendedThreadTask {
4872 public:
4873 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
4874 ExtendedPC result();
4875 protected:
4876 void do_task(const os::SuspendedThreadTaskContext& context);
4877 private:
4878 ExtendedPC _epc;
4879 };
4880
4881 ExtendedPC PcFetcher::result() {
4882 guarantee(is_done(), "task is not done yet.");
4883 return _epc;
4884 }
4885
4886 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
4887 Thread* thread = context.thread();
4888 OSThread* osthread = thread->osthread();
4889 if (osthread->ucontext() != NULL) {
4890 _epc = os::Linux::ucontext_get_pc((const ucontext_t *) context.ucontext());
4891 } else {
4892 // NULL context is unexpected, double-check this is the VMThread
4893 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4894 }
4895 }
4896
4897 // Suspends the target using the signal mechanism and then grabs the PC before
4898 // resuming the target. Used by the flat-profiler only
4899 ExtendedPC os::get_thread_pc(Thread* thread) {
4900 // Make sure that it is called by the watcher for the VMThread
4901 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4902 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4903
4904 PcFetcher fetcher(thread);
4905 fetcher.run();
4906 return fetcher.result();
4907 }
4908
4909 ////////////////////////////////////////////////////////////////////////////////
4910 // debug support
4911
4912 bool os::find(address addr, outputStream* st) {
4913 Dl_info dlinfo;
4914 memset(&dlinfo, 0, sizeof(dlinfo));
4915 if (dladdr(addr, &dlinfo) != 0) {
4916 st->print(PTR_FORMAT ": ", p2i(addr));
4917 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
4918 st->print("%s+" PTR_FORMAT, dlinfo.dli_sname,
4919 p2i(addr) - p2i(dlinfo.dli_saddr));
4920 } else if (dlinfo.dli_fbase != NULL) {
4921 st->print("<offset " PTR_FORMAT ">", p2i(addr) - p2i(dlinfo.dli_fbase));
4922 } else {
4923 st->print("<absolute address>");
4924 }
4925 if (dlinfo.dli_fname != NULL) {
4926 st->print(" in %s", dlinfo.dli_fname);
4927 }
4928 if (dlinfo.dli_fbase != NULL) {
4929 st->print(" at " PTR_FORMAT, p2i(dlinfo.dli_fbase));
4930 }
4931 st->cr();
4932
4933 if (Verbose) {
4934 // decode some bytes around the PC
4935 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
4936 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
4937 address lowest = (address) dlinfo.dli_sname;
4938 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4939 if (begin < lowest) begin = lowest;
4940 Dl_info dlinfo2;
4941 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
4942 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin) {
4943 end = (address) dlinfo2.dli_saddr;
4944 }
4945 Disassembler::decode(begin, end, st);
4946 }
4947 return true;
4948 }
4949 return false;
4950 }
4951
4952 ////////////////////////////////////////////////////////////////////////////////
4953 // misc
4954
4955 // This does not do anything on Linux. This is basically a hook for being
4956 // able to use structured exception handling (thread-local exception filters)
4957 // on, e.g., Win32.
4958 void
4959 os::os_exception_wrapper(java_call_t f, JavaValue* value, const methodHandle& method,
4960 JavaCallArguments* args, Thread* thread) {
4961 f(value, method, args, thread);
4962 }
4963
4964 void os::print_statistics() {
4965 }
4966
4967 bool os::message_box(const char* title, const char* message) {
4968 int i;
4969 fdStream err(defaultStream::error_fd());
4970 for (i = 0; i < 78; i++) err.print_raw("=");
4971 err.cr();
4972 err.print_raw_cr(title);
4973 for (i = 0; i < 78; i++) err.print_raw("-");
4974 err.cr();
4975 err.print_raw_cr(message);
4976 for (i = 0; i < 78; i++) err.print_raw("=");
4977 err.cr();
4978
4979 char buf[16];
4980 // Prevent process from exiting upon "read error" without consuming all CPU
4981 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4982
4983 return buf[0] == 'y' || buf[0] == 'Y';
4984 }
4985
4986 int os::stat(const char *path, struct stat *sbuf) {
4987 char pathbuf[MAX_PATH];
4988 if (strlen(path) > MAX_PATH - 1) {
4989 errno = ENAMETOOLONG;
4990 return -1;
4991 }
4992 os::native_path(strcpy(pathbuf, path));
4993 return ::stat(pathbuf, sbuf);
4994 }
4995
4996 bool os::check_heap(bool force) {
4997 return true;
4998 }
4999
5000 // Is a (classpath) directory empty?
5001 bool os::dir_is_empty(const char* path) {
5002 DIR *dir = NULL;
5003 struct dirent *ptr;
5004
5005 dir = opendir(path);
5006 if (dir == NULL) return true;
5007
5008 // Scan the directory
5009 bool result = true;
5010 char buf[sizeof(struct dirent) + MAX_PATH];
5011 while (result && (ptr = ::readdir(dir)) != NULL) {
5012 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5013 result = false;
5014 }
5015 }
5016 closedir(dir);
5017 return result;
5018 }
5019
5020 // This code originates from JDK's sysOpen and open64_w
5021 // from src/solaris/hpi/src/system_md.c
5022
5023 int os::open(const char *path, int oflag, int mode) {
5024 if (strlen(path) > MAX_PATH - 1) {
5025 errno = ENAMETOOLONG;
5026 return -1;
5027 }
5028
5029 // All file descriptors that are opened in the Java process and not
5030 // specifically destined for a subprocess should have the close-on-exec
5031 // flag set. If we don't set it, then careless 3rd party native code
5032 // might fork and exec without closing all appropriate file descriptors
5033 // (e.g. as we do in closeDescriptors in UNIXProcess.c), and this in
5034 // turn might:
5035 //
5036 // - cause end-of-file to fail to be detected on some file
5037 // descriptors, resulting in mysterious hangs, or
5038 //
5039 // - might cause an fopen in the subprocess to fail on a system
5040 // suffering from bug 1085341.
5041 //
5042 // (Yes, the default setting of the close-on-exec flag is a Unix
5043 // design flaw)
5044 //
5045 // See:
5046 // 1085341: 32-bit stdio routines should support file descriptors >255
5047 // 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5048 // 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5049 //
5050 // Modern Linux kernels (after 2.6.23 2007) support O_CLOEXEC with open().
5051 // O_CLOEXEC is preferable to using FD_CLOEXEC on an open file descriptor
5052 // because it saves a system call and removes a small window where the flag
5053 // is unset. On ancient Linux kernels the O_CLOEXEC flag will be ignored
5054 // and we fall back to using FD_CLOEXEC (see below).
5055 #ifdef O_CLOEXEC
5056 oflag |= O_CLOEXEC;
5057 #endif
5058
5059 int fd = ::open64(path, oflag, mode);
5060 if (fd == -1) return -1;
5061
5062 //If the open succeeded, the file might still be a directory
5063 {
5064 struct stat64 buf64;
5065 int ret = ::fstat64(fd, &buf64);
5066 int st_mode = buf64.st_mode;
5067
5068 if (ret != -1) {
5069 if ((st_mode & S_IFMT) == S_IFDIR) {
5070 errno = EISDIR;
5071 ::close(fd);
5072 return -1;
5073 }
5074 } else {
5075 ::close(fd);
5076 return -1;
5077 }
5078 }
5079
5080 #ifdef FD_CLOEXEC
5081 // Validate that the use of the O_CLOEXEC flag on open above worked.
5082 // With recent kernels, we will perform this check exactly once.
5083 static sig_atomic_t O_CLOEXEC_is_known_to_work = 0;
5084 if (!O_CLOEXEC_is_known_to_work) {
5085 int flags = ::fcntl(fd, F_GETFD);
5086 if (flags != -1) {
5087 if ((flags & FD_CLOEXEC) != 0)
5088 O_CLOEXEC_is_known_to_work = 1;
5089 else
5090 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5091 }
5092 }
5093 #endif
5094
5095 return fd;
5096 }
5097
5098
5099 // create binary file, rewriting existing file if required
5100 int os::create_binary_file(const char* path, bool rewrite_existing) {
5101 int oflags = O_WRONLY | O_CREAT;
5102 if (!rewrite_existing) {
5103 oflags |= O_EXCL;
5104 }
5105 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5106 }
5107
5108 // return current position of file pointer
5109 jlong os::current_file_offset(int fd) {
5110 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5111 }
5112
5113 // move file pointer to the specified offset
5114 jlong os::seek_to_file_offset(int fd, jlong offset) {
5115 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5116 }
5117
5118 // This code originates from JDK's sysAvailable
5119 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5120
5121 int os::available(int fd, jlong *bytes) {
5122 jlong cur, end;
5123 int mode;
5124 struct stat64 buf64;
5125
5126 if (::fstat64(fd, &buf64) >= 0) {
5127 mode = buf64.st_mode;
5128 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5129 int n;
5130 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5131 *bytes = n;
5132 return 1;
5133 }
5134 }
5135 }
5136 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5137 return 0;
5138 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5139 return 0;
5140 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5141 return 0;
5142 }
5143 *bytes = end - cur;
5144 return 1;
5145 }
5146
5147 // Map a block of memory.
5148 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5149 char *addr, size_t bytes, bool read_only,
5150 bool allow_exec) {
5151 int prot;
5152 int flags = MAP_PRIVATE;
5153
5154 if (read_only) {
5155 prot = PROT_READ;
5156 } else {
5157 prot = PROT_READ | PROT_WRITE;
5158 }
5159
5160 if (allow_exec) {
5161 prot |= PROT_EXEC;
5162 }
5163
5164 if (addr != NULL) {
5165 flags |= MAP_FIXED;
5166 }
5167
5168 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5169 fd, file_offset);
5170 if (mapped_address == MAP_FAILED) {
5171 return NULL;
5172 }
5173 return mapped_address;
5174 }
5175
5176
5177 // Remap a block of memory.
5178 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5179 char *addr, size_t bytes, bool read_only,
5180 bool allow_exec) {
5181 // same as map_memory() on this OS
5182 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5183 allow_exec);
5184 }
5185
5186
5187 // Unmap a block of memory.
5188 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5189 return munmap(addr, bytes) == 0;
5190 }
5191
5192 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5193
5194 static clockid_t thread_cpu_clockid(Thread* thread) {
5195 pthread_t tid = thread->osthread()->pthread_id();
5196 clockid_t clockid;
5197
5198 // Get thread clockid
5199 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5200 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5201 return clockid;
5202 }
5203
5204 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5205 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5206 // of a thread.
5207 //
5208 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5209 // the fast estimate available on the platform.
5210
5211 jlong os::current_thread_cpu_time() {
5212 if (os::Linux::supports_fast_thread_cpu_time()) {
5213 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5214 } else {
5215 // return user + sys since the cost is the same
5216 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5217 }
5218 }
5219
5220 jlong os::thread_cpu_time(Thread* thread) {
5221 // consistent with what current_thread_cpu_time() returns
5222 if (os::Linux::supports_fast_thread_cpu_time()) {
5223 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5224 } else {
5225 return slow_thread_cpu_time(thread, true /* user + sys */);
5226 }
5227 }
5228
5229 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5230 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5231 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5232 } else {
5233 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5234 }
5235 }
5236
5237 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5238 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5239 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5240 } else {
5241 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5242 }
5243 }
5244
5245 // -1 on error.
5246 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5247 pid_t tid = thread->osthread()->thread_id();
5248 char *s;
5249 char stat[2048];
5250 int statlen;
5251 char proc_name[64];
5252 int count;
5253 long sys_time, user_time;
5254 char cdummy;
5255 int idummy;
5256 long ldummy;
5257 FILE *fp;
5258
5259 snprintf(proc_name, 64, "/proc/self/task/%d/stat", tid);
5260 fp = fopen(proc_name, "r");
5261 if (fp == NULL) return -1;
5262 statlen = fread(stat, 1, 2047, fp);
5263 stat[statlen] = '\0';
5264 fclose(fp);
5265
5266 // Skip pid and the command string. Note that we could be dealing with
5267 // weird command names, e.g. user could decide to rename java launcher
5268 // to "java 1.4.2 :)", then the stat file would look like
5269 // 1234 (java 1.4.2 :)) R ... ...
5270 // We don't really need to know the command string, just find the last
5271 // occurrence of ")" and then start parsing from there. See bug 4726580.
5272 s = strrchr(stat, ')');
5273 if (s == NULL) return -1;
5274
5275 // Skip blank chars
5276 do { s++; } while (s && isspace(*s));
5277
5278 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5279 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5280 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5281 &user_time, &sys_time);
5282 if (count != 13) return -1;
5283 if (user_sys_cpu_time) {
5284 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5285 } else {
5286 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5287 }
5288 }
5289
5290 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5291 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5292 info_ptr->may_skip_backward = false; // elapsed time not wall time
5293 info_ptr->may_skip_forward = false; // elapsed time not wall time
5294 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5295 }
5296
5297 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5298 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5299 info_ptr->may_skip_backward = false; // elapsed time not wall time
5300 info_ptr->may_skip_forward = false; // elapsed time not wall time
5301 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5302 }
5303
5304 bool os::is_thread_cpu_time_supported() {
5305 return true;
5306 }
5307
5308 // System loadavg support. Returns -1 if load average cannot be obtained.
5309 // Linux doesn't yet have a (official) notion of processor sets,
5310 // so just return the system wide load average.
5311 int os::loadavg(double loadavg[], int nelem) {
5312 return ::getloadavg(loadavg, nelem);
5313 }
5314
5315 void os::pause() {
5316 char filename[MAX_PATH];
5317 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5318 jio_snprintf(filename, MAX_PATH, "%s", PauseAtStartupFile);
5319 } else {
5320 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5321 }
5322
5323 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5324 if (fd != -1) {
5325 struct stat buf;
5326 ::close(fd);
5327 while (::stat(filename, &buf) == 0) {
5328 (void)::poll(NULL, 0, 100);
5329 }
5330 } else {
5331 jio_fprintf(stderr,
5332 "Could not open pause file '%s', continuing immediately.\n", filename);
5333 }
5334 }
5335
5336
5337 // Refer to the comments in os_solaris.cpp park-unpark. The next two
5338 // comment paragraphs are worth repeating here:
5339 //
5340 // Assumption:
5341 // Only one parker can exist on an event, which is why we allocate
5342 // them per-thread. Multiple unparkers can coexist.
5343 //
5344 // _Event serves as a restricted-range semaphore.
5345 // -1 : thread is blocked, i.e. there is a waiter
5346 // 0 : neutral: thread is running or ready,
5347 // could have been signaled after a wait started
5348 // 1 : signaled - thread is running or ready
5349 //
5350 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5351 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5352 // For specifics regarding the bug see GLIBC BUGID 261237 :
5353 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5354 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5355 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5356 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5357 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5358 // and monitorenter when we're using 1-0 locking. All those operations may result in
5359 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5360 // of libpthread avoids the problem, but isn't practical.
5361 //
5362 // Possible remedies:
5363 //
5364 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5365 // This is palliative and probabilistic, however. If the thread is preempted
5366 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5367 // than the minimum period may have passed, and the abstime may be stale (in the
5368 // past) resultin in a hang. Using this technique reduces the odds of a hang
5369 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5370 //
5371 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5372 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5373 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5374 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5375 // thread.
5376 //
5377 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5378 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5379 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5380 // This also works well. In fact it avoids kernel-level scalability impediments
5381 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5382 // timers in a graceful fashion.
5383 //
5384 // 4. When the abstime value is in the past it appears that control returns
5385 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5386 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5387 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5388 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5389 // It may be possible to avoid reinitialization by checking the return
5390 // value from pthread_cond_timedwait(). In addition to reinitializing the
5391 // condvar we must establish the invariant that cond_signal() is only called
5392 // within critical sections protected by the adjunct mutex. This prevents
5393 // cond_signal() from "seeing" a condvar that's in the midst of being
5394 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5395 // desirable signal-after-unlock optimization that avoids futile context switching.
5396 //
5397 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5398 // structure when a condvar is used or initialized. cond_destroy() would
5399 // release the helper structure. Our reinitialize-after-timedwait fix
5400 // put excessive stress on malloc/free and locks protecting the c-heap.
5401 //
5402 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5403 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5404 // and only enabling the work-around for vulnerable environments.
5405
5406 // utility to compute the abstime argument to timedwait:
5407 // millis is the relative timeout time
5408 // abstime will be the absolute timeout time
5409 // TODO: replace compute_abstime() with unpackTime()
5410
5411 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5412 if (millis < 0) millis = 0;
5413
5414 jlong seconds = millis / 1000;
5415 millis %= 1000;
5416 if (seconds > 50000000) { // see man cond_timedwait(3T)
5417 seconds = 50000000;
5418 }
5419
5420 if (os::supports_monotonic_clock()) {
5421 struct timespec now;
5422 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5423 assert_status(status == 0, status, "clock_gettime");
5424 abstime->tv_sec = now.tv_sec + seconds;
5425 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5426 if (nanos >= NANOSECS_PER_SEC) {
5427 abstime->tv_sec += 1;
5428 nanos -= NANOSECS_PER_SEC;
5429 }
5430 abstime->tv_nsec = nanos;
5431 } else {
5432 struct timeval now;
5433 int status = gettimeofday(&now, NULL);
5434 assert(status == 0, "gettimeofday");
5435 abstime->tv_sec = now.tv_sec + seconds;
5436 long usec = now.tv_usec + millis * 1000;
5437 if (usec >= 1000000) {
5438 abstime->tv_sec += 1;
5439 usec -= 1000000;
5440 }
5441 abstime->tv_nsec = usec * 1000;
5442 }
5443 return abstime;
5444 }
5445
5446 void os::PlatformEvent::park() { // AKA "down()"
5447 // Transitions for _Event:
5448 // -1 => -1 : illegal
5449 // 1 => 0 : pass - return immediately
5450 // 0 => -1 : block; then set _Event to 0 before returning
5451
5452 // Invariant: Only the thread associated with the Event/PlatformEvent
5453 // may call park().
5454 // TODO: assert that _Assoc != NULL or _Assoc == Self
5455 assert(_nParked == 0, "invariant");
5456
5457 int v;
5458 for (;;) {
5459 v = _Event;
5460 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5461 }
5462 guarantee(v >= 0, "invariant");
5463 if (v == 0) {
5464 // Do this the hard way by blocking ...
5465 int status = pthread_mutex_lock(_mutex);
5466 assert_status(status == 0, status, "mutex_lock");
5467 guarantee(_nParked == 0, "invariant");
5468 ++_nParked;
5469 while (_Event < 0) {
5470 status = pthread_cond_wait(_cond, _mutex);
5471 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5472 // Treat this the same as if the wait was interrupted
5473 if (status == ETIME) { status = EINTR; }
5474 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5475 }
5476 --_nParked;
5477
5478 _Event = 0;
5479 status = pthread_mutex_unlock(_mutex);
5480 assert_status(status == 0, status, "mutex_unlock");
5481 // Paranoia to ensure our locked and lock-free paths interact
5482 // correctly with each other.
5483 OrderAccess::fence();
5484 }
5485 guarantee(_Event >= 0, "invariant");
5486 }
5487
5488 int os::PlatformEvent::park(jlong millis) {
5489 // Transitions for _Event:
5490 // -1 => -1 : illegal
5491 // 1 => 0 : pass - return immediately
5492 // 0 => -1 : block; then set _Event to 0 before returning
5493
5494 guarantee(_nParked == 0, "invariant");
5495
5496 int v;
5497 for (;;) {
5498 v = _Event;
5499 if (Atomic::cmpxchg(v-1, &_Event, v) == v) break;
5500 }
5501 guarantee(v >= 0, "invariant");
5502 if (v != 0) return OS_OK;
5503
5504 // We do this the hard way, by blocking the thread.
5505 // Consider enforcing a minimum timeout value.
5506 struct timespec abst;
5507 compute_abstime(&abst, millis);
5508
5509 int ret = OS_TIMEOUT;
5510 int status = pthread_mutex_lock(_mutex);
5511 assert_status(status == 0, status, "mutex_lock");
5512 guarantee(_nParked == 0, "invariant");
5513 ++_nParked;
5514
5515 // Object.wait(timo) will return because of
5516 // (a) notification
5517 // (b) timeout
5518 // (c) thread.interrupt
5519 //
5520 // Thread.interrupt and object.notify{All} both call Event::set.
5521 // That is, we treat thread.interrupt as a special case of notification.
5522 // We ignore spurious OS wakeups unless FilterSpuriousWakeups is false.
5523 // We assume all ETIME returns are valid.
5524 //
5525 // TODO: properly differentiate simultaneous notify+interrupt.
5526 // In that case, we should propagate the notify to another waiter.
5527
5528 while (_Event < 0) {
5529 status = pthread_cond_timedwait(_cond, _mutex, &abst);
5530 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5531 pthread_cond_destroy(_cond);
5532 pthread_cond_init(_cond, os::Linux::condAttr());
5533 }
5534 assert_status(status == 0 || status == EINTR ||
5535 status == ETIME || status == ETIMEDOUT,
5536 status, "cond_timedwait");
5537 if (!FilterSpuriousWakeups) break; // previous semantics
5538 if (status == ETIME || status == ETIMEDOUT) break;
5539 // We consume and ignore EINTR and spurious wakeups.
5540 }
5541 --_nParked;
5542 if (_Event >= 0) {
5543 ret = OS_OK;
5544 }
5545 _Event = 0;
5546 status = pthread_mutex_unlock(_mutex);
5547 assert_status(status == 0, status, "mutex_unlock");
5548 assert(_nParked == 0, "invariant");
5549 // Paranoia to ensure our locked and lock-free paths interact
5550 // correctly with each other.
5551 OrderAccess::fence();
5552 return ret;
5553 }
5554
5555 void os::PlatformEvent::unpark() {
5556 // Transitions for _Event:
5557 // 0 => 1 : just return
5558 // 1 => 1 : just return
5559 // -1 => either 0 or 1; must signal target thread
5560 // That is, we can safely transition _Event from -1 to either
5561 // 0 or 1.
5562 // See also: "Semaphores in Plan 9" by Mullender & Cox
5563 //
5564 // Note: Forcing a transition from "-1" to "1" on an unpark() means
5565 // that it will take two back-to-back park() calls for the owning
5566 // thread to block. This has the benefit of forcing a spurious return
5567 // from the first park() call after an unpark() call which will help
5568 // shake out uses of park() and unpark() without condition variables.
5569
5570 if (Atomic::xchg(1, &_Event) >= 0) return;
5571
5572 // Wait for the thread associated with the event to vacate
5573 int status = pthread_mutex_lock(_mutex);
5574 assert_status(status == 0, status, "mutex_lock");
5575 int AnyWaiters = _nParked;
5576 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
5577 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5578 AnyWaiters = 0;
5579 pthread_cond_signal(_cond);
5580 }
5581 status = pthread_mutex_unlock(_mutex);
5582 assert_status(status == 0, status, "mutex_unlock");
5583 if (AnyWaiters != 0) {
5584 // Note that we signal() *after* dropping the lock for "immortal" Events.
5585 // This is safe and avoids a common class of futile wakeups. In rare
5586 // circumstances this can cause a thread to return prematurely from
5587 // cond_{timed}wait() but the spurious wakeup is benign and the victim
5588 // will simply re-test the condition and re-park itself.
5589 // This provides particular benefit if the underlying platform does not
5590 // provide wait morphing.
5591 status = pthread_cond_signal(_cond);
5592 assert_status(status == 0, status, "cond_signal");
5593 }
5594 }
5595
5596
5597 // JSR166
5598 // -------------------------------------------------------
5599
5600 // The solaris and linux implementations of park/unpark are fairly
5601 // conservative for now, but can be improved. They currently use a
5602 // mutex/condvar pair, plus a a count.
5603 // Park decrements count if > 0, else does a condvar wait. Unpark
5604 // sets count to 1 and signals condvar. Only one thread ever waits
5605 // on the condvar. Contention seen when trying to park implies that someone
5606 // is unparking you, so don't wait. And spurious returns are fine, so there
5607 // is no need to track notifications.
5608
5609 // This code is common to linux and solaris and will be moved to a
5610 // common place in dolphin.
5611 //
5612 // The passed in time value is either a relative time in nanoseconds
5613 // or an absolute time in milliseconds. Either way it has to be unpacked
5614 // into suitable seconds and nanoseconds components and stored in the
5615 // given timespec structure.
5616 // Given time is a 64-bit value and the time_t used in the timespec is only
5617 // a signed-32-bit value (except on 64-bit Linux) we have to watch for
5618 // overflow if times way in the future are given. Further on Solaris versions
5619 // prior to 10 there is a restriction (see cond_timedwait) that the specified
5620 // number of seconds, in abstime, is less than current_time + 100,000,000.
5621 // As it will be 28 years before "now + 100000000" will overflow we can
5622 // ignore overflow and just impose a hard-limit on seconds using the value
5623 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
5624 // years from "now".
5625
5626 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5627 assert(time > 0, "convertTime");
5628 time_t max_secs = 0;
5629
5630 if (!os::supports_monotonic_clock() || isAbsolute) {
5631 struct timeval now;
5632 int status = gettimeofday(&now, NULL);
5633 assert(status == 0, "gettimeofday");
5634
5635 max_secs = now.tv_sec + MAX_SECS;
5636
5637 if (isAbsolute) {
5638 jlong secs = time / 1000;
5639 if (secs > max_secs) {
5640 absTime->tv_sec = max_secs;
5641 } else {
5642 absTime->tv_sec = secs;
5643 }
5644 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5645 } else {
5646 jlong secs = time / NANOSECS_PER_SEC;
5647 if (secs >= MAX_SECS) {
5648 absTime->tv_sec = max_secs;
5649 absTime->tv_nsec = 0;
5650 } else {
5651 absTime->tv_sec = now.tv_sec + secs;
5652 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5653 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5654 absTime->tv_nsec -= NANOSECS_PER_SEC;
5655 ++absTime->tv_sec; // note: this must be <= max_secs
5656 }
5657 }
5658 }
5659 } else {
5660 // must be relative using monotonic clock
5661 struct timespec now;
5662 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5663 assert_status(status == 0, status, "clock_gettime");
5664 max_secs = now.tv_sec + MAX_SECS;
5665 jlong secs = time / NANOSECS_PER_SEC;
5666 if (secs >= MAX_SECS) {
5667 absTime->tv_sec = max_secs;
5668 absTime->tv_nsec = 0;
5669 } else {
5670 absTime->tv_sec = now.tv_sec + secs;
5671 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
5672 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5673 absTime->tv_nsec -= NANOSECS_PER_SEC;
5674 ++absTime->tv_sec; // note: this must be <= max_secs
5675 }
5676 }
5677 }
5678 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5679 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5680 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5681 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5682 }
5683
5684 void Parker::park(bool isAbsolute, jlong time) {
5685 // Ideally we'd do something useful while spinning, such
5686 // as calling unpackTime().
5687
5688 // Optional fast-path check:
5689 // Return immediately if a permit is available.
5690 // We depend on Atomic::xchg() having full barrier semantics
5691 // since we are doing a lock-free update to _counter.
5692 if (Atomic::xchg(0, &_counter) > 0) return;
5693
5694 Thread* thread = Thread::current();
5695 assert(thread->is_Java_thread(), "Must be JavaThread");
5696 JavaThread *jt = (JavaThread *)thread;
5697
5698 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5699 // Check interrupt before trying to wait
5700 if (Thread::is_interrupted(thread, false)) {
5701 return;
5702 }
5703
5704 // Next, demultiplex/decode time arguments
5705 timespec absTime;
5706 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
5707 return;
5708 }
5709 if (time > 0) {
5710 unpackTime(&absTime, isAbsolute, time);
5711 }
5712
5713
5714 // Enter safepoint region
5715 // Beware of deadlocks such as 6317397.
5716 // The per-thread Parker:: mutex is a classic leaf-lock.
5717 // In particular a thread must never block on the Threads_lock while
5718 // holding the Parker:: mutex. If safepoints are pending both the
5719 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5720 ThreadBlockInVM tbivm(jt);
5721
5722 // Don't wait if cannot get lock since interference arises from
5723 // unblocking. Also. check interrupt before trying wait
5724 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5725 return;
5726 }
5727
5728 int status;
5729 if (_counter > 0) { // no wait needed
5730 _counter = 0;
5731 status = pthread_mutex_unlock(_mutex);
5732 assert(status == 0, "invariant");
5733 // Paranoia to ensure our locked and lock-free paths interact
5734 // correctly with each other and Java-level accesses.
5735 OrderAccess::fence();
5736 return;
5737 }
5738
5739 #ifdef ASSERT
5740 // Don't catch signals while blocked; let the running threads have the signals.
5741 // (This allows a debugger to break into the running thread.)
5742 sigset_t oldsigs;
5743 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5744 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5745 #endif
5746
5747 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5748 jt->set_suspend_equivalent();
5749 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5750
5751 assert(_cur_index == -1, "invariant");
5752 if (time == 0) {
5753 _cur_index = REL_INDEX; // arbitrary choice when not timed
5754 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
5755 } else {
5756 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
5757 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
5758 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5759 pthread_cond_destroy(&_cond[_cur_index]);
5760 pthread_cond_init(&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
5761 }
5762 }
5763 _cur_index = -1;
5764 assert_status(status == 0 || status == EINTR ||
5765 status == ETIME || status == ETIMEDOUT,
5766 status, "cond_timedwait");
5767
5768 #ifdef ASSERT
5769 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5770 #endif
5771
5772 _counter = 0;
5773 status = pthread_mutex_unlock(_mutex);
5774 assert_status(status == 0, status, "invariant");
5775 // Paranoia to ensure our locked and lock-free paths interact
5776 // correctly with each other and Java-level accesses.
5777 OrderAccess::fence();
5778
5779 // If externally suspended while waiting, re-suspend
5780 if (jt->handle_special_suspend_equivalent_condition()) {
5781 jt->java_suspend_self();
5782 }
5783 }
5784
5785 void Parker::unpark() {
5786 int status = pthread_mutex_lock(_mutex);
5787 assert(status == 0, "invariant");
5788 const int s = _counter;
5789 _counter = 1;
5790 if (s < 1) {
5791 // thread might be parked
5792 if (_cur_index != -1) {
5793 // thread is definitely parked
5794 if (WorkAroundNPTLTimedWaitHang) {
5795 status = pthread_cond_signal(&_cond[_cur_index]);
5796 assert(status == 0, "invariant");
5797 status = pthread_mutex_unlock(_mutex);
5798 assert(status == 0, "invariant");
5799 } else {
5800 // must capture correct index before unlocking
5801 int index = _cur_index;
5802 status = pthread_mutex_unlock(_mutex);
5803 assert(status == 0, "invariant");
5804 status = pthread_cond_signal(&_cond[index]);
5805 assert(status == 0, "invariant");
5806 }
5807 } else {
5808 pthread_mutex_unlock(_mutex);
5809 assert(status == 0, "invariant");
5810 }
5811 } else {
5812 pthread_mutex_unlock(_mutex);
5813 assert(status == 0, "invariant");
5814 }
5815 }
5816
5817
5818 extern char** environ;
5819
5820 // Run the specified command in a separate process. Return its exit value,
5821 // or -1 on failure (e.g. can't fork a new process).
5822 // Unlike system(), this function can be called from signal handler. It
5823 // doesn't block SIGINT et al.
5824 int os::fork_and_exec(char* cmd) {
5825 const char * argv[4] = {"sh", "-c", cmd, NULL};
5826
5827 pid_t pid = fork();
5828
5829 if (pid < 0) {
5830 // fork failed
5831 return -1;
5832
5833 } else if (pid == 0) {
5834 // child process
5835
5836 execve("/bin/sh", (char* const*)argv, environ);
5837
5838 // execve failed
5839 _exit(-1);
5840
5841 } else {
5842 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5843 // care about the actual exit code, for now.
5844
5845 int status;
5846
5847 // Wait for the child process to exit. This returns immediately if
5848 // the child has already exited. */
5849 while (waitpid(pid, &status, 0) < 0) {
5850 switch (errno) {
5851 case ECHILD: return 0;
5852 case EINTR: break;
5853 default: return -1;
5854 }
5855 }
5856
5857 if (WIFEXITED(status)) {
5858 // The child exited normally; get its exit code.
5859 return WEXITSTATUS(status);
5860 } else if (WIFSIGNALED(status)) {
5861 // The child exited because of a signal
5862 // The best value to return is 0x80 + signal number,
5863 // because that is what all Unix shells do, and because
5864 // it allows callers to distinguish between process exit and
5865 // process death by signal.
5866 return 0x80 + WTERMSIG(status);
5867 } else {
5868 // Unknown exit code; pass it through
5869 return status;
5870 }
5871 }
5872 }
5873
5874 // is_headless_jre()
5875 //
5876 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5877 // in order to report if we are running in a headless jre
5878 //
5879 // Since JDK8 xawt/libmawt.so was moved into the same directory
5880 // as libawt.so, and renamed libawt_xawt.so
5881 //
5882 bool os::is_headless_jre() {
5883 struct stat statbuf;
5884 char buf[MAXPATHLEN];
5885 char libmawtpath[MAXPATHLEN];
5886 const char *xawtstr = "/xawt/libmawt.so";
5887 const char *new_xawtstr = "/libawt_xawt.so";
5888 char *p;
5889
5890 // Get path to libjvm.so
5891 os::jvm_path(buf, sizeof(buf));
5892
5893 // Get rid of libjvm.so
5894 p = strrchr(buf, '/');
5895 if (p == NULL) {
5896 return false;
5897 } else {
5898 *p = '\0';
5899 }
5900
5901 // Get rid of client or server
5902 p = strrchr(buf, '/');
5903 if (p == NULL) {
5904 return false;
5905 } else {
5906 *p = '\0';
5907 }
5908
5909 // check xawt/libmawt.so
5910 strcpy(libmawtpath, buf);
5911 strcat(libmawtpath, xawtstr);
5912 if (::stat(libmawtpath, &statbuf) == 0) return false;
5913
5914 // check libawt_xawt.so
5915 strcpy(libmawtpath, buf);
5916 strcat(libmawtpath, new_xawtstr);
5917 if (::stat(libmawtpath, &statbuf) == 0) return false;
5918
5919 return true;
5920 }
5921
5922 // Get the default path to the core file
5923 // Returns the length of the string
5924 int os::get_core_path(char* buffer, size_t bufferSize) {
5925 /*
5926 * Max length of /proc/sys/kernel/core_pattern is 128 characters.
5927 * See https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
5928 */
5929 const int core_pattern_len = 129;
5930 char core_pattern[core_pattern_len] = {0};
5931
5932 int core_pattern_file = ::open("/proc/sys/kernel/core_pattern", O_RDONLY);
5933 if (core_pattern_file == -1) {
5934 return -1;
5935 }
5936
5937 ssize_t ret = ::read(core_pattern_file, core_pattern, core_pattern_len);
5938 ::close(core_pattern_file);
5939 if (ret <= 0 || ret >= core_pattern_len || core_pattern[0] == '\n') {
5940 return -1;
5941 }
5942 if (core_pattern[ret-1] == '\n') {
5943 core_pattern[ret-1] = '\0';
5944 } else {
5945 core_pattern[ret] = '\0';
5946 }
5947
5948 char *pid_pos = strstr(core_pattern, "%p");
5949 int written;
5950
5951 if (core_pattern[0] == '/') {
5952 written = jio_snprintf(buffer, bufferSize, "%s", core_pattern);
5953 } else {
5954 char cwd[PATH_MAX];
5955
5956 const char* p = get_current_directory(cwd, PATH_MAX);
5957 if (p == NULL) {
5958 return -1;
5959 }
5960
5961 if (core_pattern[0] == '|') {
5962 written = jio_snprintf(buffer, bufferSize,
5963 "\"%s\" (or dumping to %s/core.%d)",
5964 &core_pattern[1], p, current_process_id());
5965 } else {
5966 written = jio_snprintf(buffer, bufferSize, "%s/%s", p, core_pattern);
5967 }
5968 }
5969
5970 if (written < 0) {
5971 return -1;
5972 }
5973
5974 if (((size_t)written < bufferSize) && (pid_pos == NULL) && (core_pattern[0] != '|')) {
5975 int core_uses_pid_file = ::open("/proc/sys/kernel/core_uses_pid", O_RDONLY);
5976
5977 if (core_uses_pid_file != -1) {
5978 char core_uses_pid = 0;
5979 ssize_t ret = ::read(core_uses_pid_file, &core_uses_pid, 1);
5980 ::close(core_uses_pid_file);
5981
5982 if (core_uses_pid == '1') {
5983 jio_snprintf(buffer + written, bufferSize - written,
5984 ".%d", current_process_id());
5985 }
5986 }
5987 }
5988
5989 return strlen(buffer);
5990 }
5991
5992 bool os::start_debugging(char *buf, int buflen) {
5993 int len = (int)strlen(buf);
5994 char *p = &buf[len];
5995
5996 jio_snprintf(p, buflen-len,
5997 "\n\n"
5998 "Do you want to debug the problem?\n\n"
5999 "To debug, run 'gdb /proc/%d/exe %d'; then switch to thread " UINTX_FORMAT " (" INTPTR_FORMAT ")\n"
6000 "Enter 'yes' to launch gdb automatically (PATH must include gdb)\n"
6001 "Otherwise, press RETURN to abort...",
6002 os::current_process_id(), os::current_process_id(),
6003 os::current_thread_id(), os::current_thread_id());
6004
6005 bool yes = os::message_box("Unexpected Error", buf);
6006
6007 if (yes) {
6008 // yes, user asked VM to launch debugger
6009 jio_snprintf(buf, sizeof(buf), "gdb /proc/%d/exe %d",
6010 os::current_process_id(), os::current_process_id());
6011
6012 os::fork_and_exec(buf);
6013 yes = false;
6014 }
6015 return yes;
6016 }
6017
6018
6019
6020 /////////////// Unit tests ///////////////
6021
6022 #ifndef PRODUCT
6023
6024 #define test_log(...) \
6025 do { \
6026 if (VerboseInternalVMTests) { \
6027 tty->print_cr(__VA_ARGS__); \
6028 tty->flush(); \
6029 } \
6030 } while (false)
6031
6032 class TestReserveMemorySpecial : AllStatic {
6033 public:
6034 static void small_page_write(void* addr, size_t size) {
6035 size_t page_size = os::vm_page_size();
6036
6037 char* end = (char*)addr + size;
6038 for (char* p = (char*)addr; p < end; p += page_size) {
6039 *p = 1;
6040 }
6041 }
6042
6043 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6044 if (!UseHugeTLBFS) {
6045 return;
6046 }
6047
6048 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6049
6050 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6051
6052 if (addr != NULL) {
6053 small_page_write(addr, size);
6054
6055 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6056 }
6057 }
6058
6059 static void test_reserve_memory_special_huge_tlbfs_only() {
6060 if (!UseHugeTLBFS) {
6061 return;
6062 }
6063
6064 size_t lp = os::large_page_size();
6065
6066 for (size_t size = lp; size <= lp * 10; size += lp) {
6067 test_reserve_memory_special_huge_tlbfs_only(size);
6068 }
6069 }
6070
6071 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6072 size_t lp = os::large_page_size();
6073 size_t ag = os::vm_allocation_granularity();
6074
6075 // sizes to test
6076 const size_t sizes[] = {
6077 lp, lp + ag, lp + lp / 2, lp * 2,
6078 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6079 lp * 10, lp * 10 + lp / 2
6080 };
6081 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6082
6083 // For each size/alignment combination, we test three scenarios:
6084 // 1) with req_addr == NULL
6085 // 2) with a non-null req_addr at which we expect to successfully allocate
6086 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6087 // expect the allocation to either fail or to ignore req_addr
6088
6089 // Pre-allocate two areas; they shall be as large as the largest allocation
6090 // and aligned to the largest alignment we will be testing.
6091 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6092 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6093 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6094 -1, 0);
6095 assert(mapping1 != MAP_FAILED, "should work");
6096
6097 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6098 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6099 -1, 0);
6100 assert(mapping2 != MAP_FAILED, "should work");
6101
6102 // Unmap the first mapping, but leave the second mapping intact: the first
6103 // mapping will serve as a value for a "good" req_addr (case 2). The second
6104 // mapping, still intact, as "bad" req_addr (case 3).
6105 ::munmap(mapping1, mapping_size);
6106
6107 // Case 1
6108 test_log("%s, req_addr NULL:", __FUNCTION__);
6109 test_log("size align result");
6110
6111 for (int i = 0; i < num_sizes; i++) {
6112 const size_t size = sizes[i];
6113 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6114 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6115 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6116 size, alignment, p2i(p), (p != NULL ? "" : "(failed)"));
6117 if (p != NULL) {
6118 assert(is_ptr_aligned(p, alignment), "must be");
6119 small_page_write(p, size);
6120 os::Linux::release_memory_special_huge_tlbfs(p, size);
6121 }
6122 }
6123 }
6124
6125 // Case 2
6126 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6127 test_log("size align req_addr result");
6128
6129 for (int i = 0; i < num_sizes; i++) {
6130 const size_t size = sizes[i];
6131 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6132 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6133 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6134 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6135 size, alignment, p2i(req_addr), p2i(p),
6136 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6137 if (p != NULL) {
6138 assert(p == req_addr, "must be");
6139 small_page_write(p, size);
6140 os::Linux::release_memory_special_huge_tlbfs(p, size);
6141 }
6142 }
6143 }
6144
6145 // Case 3
6146 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6147 test_log("size align req_addr result");
6148
6149 for (int i = 0; i < num_sizes; i++) {
6150 const size_t size = sizes[i];
6151 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6152 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6153 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6154 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6155 size, alignment, p2i(req_addr), p2i(p), ((p != NULL ? "" : "(failed)")));
6156 // as the area around req_addr contains already existing mappings, the API should always
6157 // return NULL (as per contract, it cannot return another address)
6158 assert(p == NULL, "must be");
6159 }
6160 }
6161
6162 ::munmap(mapping2, mapping_size);
6163
6164 }
6165
6166 static void test_reserve_memory_special_huge_tlbfs() {
6167 if (!UseHugeTLBFS) {
6168 return;
6169 }
6170
6171 test_reserve_memory_special_huge_tlbfs_only();
6172 test_reserve_memory_special_huge_tlbfs_mixed();
6173 }
6174
6175 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6176 if (!UseSHM) {
6177 return;
6178 }
6179
6180 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6181
6182 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6183
6184 if (addr != NULL) {
6185 assert(is_ptr_aligned(addr, alignment), "Check");
6186 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6187
6188 small_page_write(addr, size);
6189
6190 os::Linux::release_memory_special_shm(addr, size);
6191 }
6192 }
6193
6194 static void test_reserve_memory_special_shm() {
6195 size_t lp = os::large_page_size();
6196 size_t ag = os::vm_allocation_granularity();
6197
6198 for (size_t size = ag; size < lp * 3; size += ag) {
6199 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6200 test_reserve_memory_special_shm(size, alignment);
6201 }
6202 }
6203 }
6204
6205 static void test() {
6206 test_reserve_memory_special_huge_tlbfs();
6207 test_reserve_memory_special_shm();
6208 }
6209 };
6210
6211 void TestReserveMemorySpecial_test() {
6212 TestReserveMemorySpecial::test();
6213 }
6214
6215 #endif