1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2012, 2016 SAP SE. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 // no precompiled headers
27 #include "asm/assembler.inline.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "code/vtableStubs.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "jvm_linux.h"
36 #include "memory/allocation.inline.hpp"
37 #include "nativeInst_ppc.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/frame.inline.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/osThread.hpp"
50 #include "runtime/sharedRuntime.hpp"
51 #include "runtime/stubRoutines.hpp"
52 #include "runtime/thread.inline.hpp"
53 #include "runtime/timer.hpp"
54 #include "utilities/events.hpp"
55 #include "utilities/vmError.hpp"
56
57 // put OS-includes here
58 # include <sys/types.h>
59 # include <sys/mman.h>
60 # include <pthread.h>
61 # include <signal.h>
62 # include <errno.h>
63 # include <dlfcn.h>
64 # include <stdlib.h>
65 # include <stdio.h>
66 # include <unistd.h>
67 # include <sys/resource.h>
68 # include <pthread.h>
69 # include <sys/stat.h>
70 # include <sys/time.h>
71 # include <sys/utsname.h>
72 # include <sys/socket.h>
73 # include <sys/wait.h>
74 # include <pwd.h>
75 # include <poll.h>
76 # include <ucontext.h>
77
78
79 address os::current_stack_pointer() {
80 intptr_t* csp;
81
82 // inline assembly `mr regno(csp), R1_SP':
83 __asm__ __volatile__ ("mr %0, 1":"=r"(csp):);
84
85 return (address) csp;
86 }
87
88 char* os::non_memory_address_word() {
89 // Must never look like an address returned by reserve_memory,
90 // even in its subfields (as defined by the CPU immediate fields,
91 // if the CPU splits constants across multiple instructions).
92
93 return (char*) -1;
94 }
95
96 void os::initialize_thread(Thread *thread) { }
97
98 // Frame information (pc, sp, fp) retrieved via ucontext
99 // always looks like a C-frame according to the frame
100 // conventions in frame_ppc64.hpp.
101 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
102 // On powerpc64, ucontext_t is not selfcontained but contains
103 // a pointer to an optional substructure (mcontext_t.regs) containing the volatile
104 // registers - NIP, among others.
105 // This substructure may or may not be there depending where uc came from:
106 // - if uc was handed over as the argument to a sigaction handler, a pointer to the
107 // substructure was provided by the kernel when calling the signal handler, and
108 // regs->nip can be accessed.
109 // - if uc was filled by getcontext(), it is undefined - getcontext() does not fill
110 // it because the volatile registers are not needed to make setcontext() work.
111 // Hopefully it was zero'd out beforehand.
112 guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_get_pc in sigaction context");
113 return (address)uc->uc_mcontext.regs->nip;
114 }
115
116 // modify PC in ucontext.
117 // Note: Only use this for an ucontext handed down to a signal handler. See comment
118 // in ucontext_get_pc.
119 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
120 guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_set_pc in sigaction context");
121 uc->uc_mcontext.regs->nip = (unsigned long)pc;
122 }
123
124 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
125 return (intptr_t*)uc->uc_mcontext.regs->gpr[1/*REG_SP*/];
126 }
127
128 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
129 return NULL;
130 }
131
132 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
133 intptr_t** ret_sp, intptr_t** ret_fp) {
134
135 ExtendedPC epc;
136 const ucontext_t* uc = (const ucontext_t*)ucVoid;
137
138 if (uc != NULL) {
139 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
140 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
141 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
142 } else {
143 // construct empty ExtendedPC for return value checking
144 epc = ExtendedPC(NULL);
145 if (ret_sp) *ret_sp = (intptr_t *)NULL;
146 if (ret_fp) *ret_fp = (intptr_t *)NULL;
147 }
148
149 return epc;
150 }
151
152 frame os::fetch_frame_from_context(const void* ucVoid) {
153 intptr_t* sp;
154 intptr_t* fp;
155 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
156 return frame(sp, epc.pc());
157 }
158
159 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
160 address pc = (address) os::Linux::ucontext_get_pc(uc);
161 if (Interpreter::contains(pc)) {
162 // Interpreter performs stack banging after the fixed frame header has
163 // been generated while the compilers perform it before. To maintain
164 // semantic consistency between interpreted and compiled frames, the
165 // method returns the Java sender of the current frame.
166 *fr = os::fetch_frame_from_context(uc);
167 if (!fr->is_first_java_frame()) {
168 assert(fr->safe_for_sender(thread), "Safety check");
169 *fr = fr->java_sender();
170 }
171 } else {
172 // More complex code with compiled code.
173 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
174 CodeBlob* cb = CodeCache::find_blob(pc);
175 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
176 // Not sure where the pc points to, fallback to default
177 // stack overflow handling. In compiled code, we bang before
178 // the frame is complete.
179 return false;
180 } else {
181 intptr_t* fp = os::Linux::ucontext_get_fp(uc);
182 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
183 *fr = frame(sp, (address)*sp);
184 if (!fr->is_java_frame()) {
185 assert(fr->safe_for_sender(thread), "Safety check");
186 assert(!fr->is_first_frame(), "Safety check");
187 *fr = fr->java_sender();
188 }
189 }
190 }
191 assert(fr->is_java_frame(), "Safety check");
192 return true;
193 }
194
195 frame os::get_sender_for_C_frame(frame* fr) {
196 if (*fr->sp() == 0) {
197 // fr is the last C frame
198 return frame(NULL, NULL);
199 }
200 return frame(fr->sender_sp(), fr->sender_pc());
201 }
202
203
204 frame os::current_frame() {
205 intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer());
206 // hack.
207 frame topframe(csp, (address)0x8);
208 // Return sender of sender of current topframe which hopefully
209 // both have pc != NULL.
210 frame tmp = os::get_sender_for_C_frame(&topframe);
211 return os::get_sender_for_C_frame(&tmp);
212 }
213
214 // Utility functions
215
216 extern "C" JNIEXPORT int
217 JVM_handle_linux_signal(int sig,
218 siginfo_t* info,
219 void* ucVoid,
220 int abort_if_unrecognized) {
221 ucontext_t* uc = (ucontext_t*) ucVoid;
222
223 Thread* t = Thread::current_or_null_safe();
224
225 SignalHandlerMark shm(t);
226
227 // Note: it's not uncommon that JNI code uses signal/sigset to install
228 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
229 // or have a SIGILL handler when detecting CPU type). When that happens,
230 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
231 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
232 // that do not require siginfo/ucontext first.
233
234 if (sig == SIGPIPE) {
235 if (os::Linux::chained_handler(sig, info, ucVoid)) {
236 return true;
237 } else {
238 // Ignoring SIGPIPE - see bugs 4229104
239 return true;
240 }
241 }
242
243 // Make the signal handler transaction-aware by checking the existence of a
244 // second (transactional) context with MSR TS bits active. If the signal is
245 // caught during a transaction, then just return to the HTM abort handler.
246 // Please refer to Linux kernel document powerpc/transactional_memory.txt,
247 // section "Signals".
248 if (uc && uc->uc_link) {
249 ucontext_t* second_uc = uc->uc_link;
250
251 // MSR TS bits are 29 and 30 (Power ISA, v2.07B, Book III-S, pp. 857-858,
252 // 3.2.1 "Machine State Register"), however note that ISA notation for bit
253 // numbering is MSB 0, so for normal bit numbering (LSB 0) they come to be
254 // bits 33 and 34. It's not related to endianness, just a notation matter.
255 if (second_uc->uc_mcontext.regs->msr & 0x600000000) {
256 if (TraceTraps) {
257 tty->print_cr("caught signal in transaction, "
258 "ignoring to jump to abort handler");
259 }
260 // Return control to the HTM abort handler.
261 return true;
262 }
263 }
264
265 JavaThread* thread = NULL;
266 VMThread* vmthread = NULL;
267 if (os::Linux::signal_handlers_are_installed) {
268 if (t != NULL) {
269 if(t->is_Java_thread()) {
270 thread = (JavaThread*)t;
271 } else if(t->is_VM_thread()) {
272 vmthread = (VMThread *)t;
273 }
274 }
275 }
276
277 // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
278 // it work if no associated JavaThread object exists.
279 if (uc) {
280 address const pc = os::Linux::ucontext_get_pc(uc);
281 if (pc && StubRoutines::is_safefetch_fault(pc)) {
282 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
283 return true;
284 }
285 }
286
287 // decide if this trap can be handled by a stub
288 address stub = NULL;
289 address pc = NULL;
290
291 //%note os_trap_1
292 if (info != NULL && uc != NULL && thread != NULL) {
293 pc = (address) os::Linux::ucontext_get_pc(uc);
294
295 // Handle ALL stack overflow variations here
296 if (sig == SIGSEGV) {
297 // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see
298 // comment below). Use get_stack_bang_address instead of si_addr.
299 address addr = ((NativeInstruction*)pc)->get_stack_bang_address(uc);
300
301 // Check if fault address is within thread stack.
302 if (thread->on_local_stack(addr)) {
303 // stack overflow
304 if (thread->in_stack_yellow_reserved_zone(addr)) {
305 if (thread->thread_state() == _thread_in_Java) {
306 if (thread->in_stack_reserved_zone(addr)) {
307 frame fr;
308 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
309 assert(fr.is_java_frame(), "Must be a Javac frame");
310 frame activation =
311 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
312 if (activation.sp() != NULL) {
313 thread->disable_stack_reserved_zone();
314 if (activation.is_interpreted_frame()) {
315 thread->set_reserved_stack_activation((address)activation.fp());
316 } else {
317 thread->set_reserved_stack_activation((address)activation.unextended_sp());
318 }
319 return 1;
320 }
321 }
322 }
323 // Throw a stack overflow exception.
324 // Guard pages will be reenabled while unwinding the stack.
325 thread->disable_stack_yellow_reserved_zone();
326 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
327 } else {
328 // Thread was in the vm or native code. Return and try to finish.
329 thread->disable_stack_yellow_reserved_zone();
330 return 1;
331 }
332 } else if (thread->in_stack_red_zone(addr)) {
333 // Fatal red zone violation. Disable the guard pages and fall through
334 // to handle_unexpected_exception way down below.
335 thread->disable_stack_red_zone();
336 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
337
338 // This is a likely cause, but hard to verify. Let's just print
339 // it as a hint.
340 tty->print_raw_cr("Please check if any of your loaded .so files has "
341 "enabled executable stack (see man page execstack(8))");
342 } else {
343 // Accessing stack address below sp may cause SEGV if current
344 // thread has MAP_GROWSDOWN stack. This should only happen when
345 // current thread was created by user code with MAP_GROWSDOWN flag
346 // and then attached to VM. See notes in os_linux.cpp.
347 if (thread->osthread()->expanding_stack() == 0) {
348 thread->osthread()->set_expanding_stack();
349 if (os::Linux::manually_expand_stack(thread, addr)) {
350 thread->osthread()->clear_expanding_stack();
351 return 1;
352 }
353 thread->osthread()->clear_expanding_stack();
354 } else {
355 fatal("recursive segv. expanding stack.");
356 }
357 }
358 }
359 }
360
361 if (thread->thread_state() == _thread_in_Java) {
362 // Java thread running in Java code => find exception handler if any
363 // a fault inside compiled code, the interpreter, or a stub
364
365 // A VM-related SIGILL may only occur if we are not in the zero page.
366 // On AIX, we get a SIGILL if we jump to 0x0 or to somewhere else
367 // in the zero page, because it is filled with 0x0. We ignore
368 // explicit SIGILLs in the zero page.
369 if (sig == SIGILL && (pc < (address) 0x200)) {
370 if (TraceTraps) {
371 tty->print_raw_cr("SIGILL happened inside zero page.");
372 }
373 goto report_and_die;
374 }
375
376 CodeBlob *cb = NULL;
377 // Handle signal from NativeJump::patch_verified_entry().
378 if (( TrapBasedNotEntrantChecks && sig == SIGTRAP && nativeInstruction_at(pc)->is_sigtrap_zombie_not_entrant()) ||
379 (!TrapBasedNotEntrantChecks && sig == SIGILL && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant())) {
380 if (TraceTraps) {
381 tty->print_cr("trap: zombie_not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL");
382 }
383 stub = SharedRuntime::get_handle_wrong_method_stub();
384 }
385
386 else if (sig == SIGSEGV &&
387 // A linux-ppc64 kernel before 2.6.6 doesn't set si_addr on some segfaults
388 // in 64bit mode (cf. http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.6),
389 // especially when we try to read from the safepoint polling page. So the check
390 // (address)info->si_addr == os::get_standard_polling_page()
391 // doesn't work for us. We use:
392 ((NativeInstruction*)pc)->is_safepoint_poll() &&
393 CodeCache::contains((void*) pc) &&
394 ((cb = CodeCache::find_blob(pc)) != NULL) &&
395 cb->is_compiled()) {
396 if (TraceTraps) {
397 tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
398 }
399 stub = SharedRuntime::get_poll_stub(pc);
400 }
401
402 // SIGTRAP-based ic miss check in compiled code.
403 else if (sig == SIGTRAP && TrapBasedICMissChecks &&
404 nativeInstruction_at(pc)->is_sigtrap_ic_miss_check()) {
405 if (TraceTraps) {
406 tty->print_cr("trap: ic_miss_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
407 }
408 stub = SharedRuntime::get_ic_miss_stub();
409 }
410
411 // SIGTRAP-based implicit null check in compiled code.
412 else if (sig == SIGTRAP && TrapBasedNullChecks &&
413 nativeInstruction_at(pc)->is_sigtrap_null_check()) {
414 if (TraceTraps) {
415 tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
416 }
417 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
418 }
419
420 // SIGSEGV-based implicit null check in compiled code.
421 else if (sig == SIGSEGV && ImplicitNullChecks &&
422 CodeCache::contains((void*) pc) &&
423 !MacroAssembler::needs_explicit_null_check((intptr_t) info->si_addr)) {
424 if (TraceTraps) {
425 tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
426 }
427 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
428 }
429
430 #ifdef COMPILER2
431 // SIGTRAP-based implicit range check in compiled code.
432 else if (sig == SIGTRAP && TrapBasedRangeChecks &&
433 nativeInstruction_at(pc)->is_sigtrap_range_check()) {
434 if (TraceTraps) {
435 tty->print_cr("trap: range_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
436 }
437 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
438 }
439 #endif
440 else if (sig == SIGBUS) {
441 // BugId 4454115: A read from a MappedByteBuffer can fault here if the
442 // underlying file has been truncated. Do not crash the VM in such a case.
443 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
444 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
445 if (nm != NULL && nm->has_unsafe_access()) {
446 address next_pc = pc + 4;
447 next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
448 os::Linux::ucontext_set_pc(uc, next_pc);
449 return true;
450 }
451 }
452 }
453
454 else { // thread->thread_state() != _thread_in_Java
455 if (sig == SIGILL && VM_Version::is_determine_features_test_running()) {
456 // SIGILL must be caused by VM_Version::determine_features().
457 *(int *)pc = 0; // patch instruction to 0 to indicate that it causes a SIGILL,
458 // flushing of icache is not necessary.
459 stub = pc + 4; // continue with next instruction.
460 }
461 else if (thread->thread_state() == _thread_in_vm &&
462 sig == SIGBUS && thread->doing_unsafe_access()) {
463 address next_pc = pc + 4;
464 next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
465 os::Linux::ucontext_set_pc(uc, pc + 4);
466 return true;
467 }
468 }
469
470 // Check to see if we caught the safepoint code in the
471 // process of write protecting the memory serialization page.
472 // It write enables the page immediately after protecting it
473 // so we can just return to retry the write.
474 if ((sig == SIGSEGV) &&
475 // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see comment above).
476 // Use is_memory_serialization instead of si_addr.
477 ((NativeInstruction*)pc)->is_memory_serialization(thread, ucVoid)) {
478 // Synchronization problem in the pseudo memory barrier code (bug id 6546278)
479 // Block current thread until the memory serialize page permission restored.
480 os::block_on_serialize_page_trap();
481 return true;
482 }
483 }
484
485 if (stub != NULL) {
486 // Save all thread context in case we need to restore it.
487 if (thread != NULL) thread->set_saved_exception_pc(pc);
488 os::Linux::ucontext_set_pc(uc, stub);
489 return true;
490 }
491
492 // signal-chaining
493 if (os::Linux::chained_handler(sig, info, ucVoid)) {
494 return true;
495 }
496
497 if (!abort_if_unrecognized) {
498 // caller wants another chance, so give it to him
499 return false;
500 }
501
502 if (pc == NULL && uc != NULL) {
503 pc = os::Linux::ucontext_get_pc(uc);
504 }
505
506 report_and_die:
507 // unmask current signal
508 sigset_t newset;
509 sigemptyset(&newset);
510 sigaddset(&newset, sig);
511 sigprocmask(SIG_UNBLOCK, &newset, NULL);
512
513 VMError::report_and_die(t, sig, pc, info, ucVoid);
514
515 ShouldNotReachHere();
516 return false;
517 }
518
519 void os::Linux::init_thread_fpu_state(void) {
520 // Disable FP exceptions.
521 __asm__ __volatile__ ("mtfsfi 6,0");
522 }
523
524 int os::Linux::get_fpu_control_word(void) {
525 // x86 has problems with FPU precision after pthread_cond_timedwait().
526 // nothing to do on ppc64.
527 return 0;
528 }
529
530 void os::Linux::set_fpu_control_word(int fpu_control) {
531 // x86 has problems with FPU precision after pthread_cond_timedwait().
532 // nothing to do on ppc64.
533 }
534
535 ////////////////////////////////////////////////////////////////////////////////
536 // thread stack
537
538 // These sizes exclude OS stack guard pages, but include
539 // the VM guard pages.
540 size_t os::Posix::_compiler_thread_min_stack_allowed = 192 * K;
541 size_t os::Posix::_java_thread_min_stack_allowed = 128 * K;
542 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
543
544 // return default stack size for thr_type
545 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
546 // default stack size (compiler thread needs larger stack)
547 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
548 return s;
549 }
550
551 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
552 // Creating guard page is very expensive. Java thread has HotSpot
553 // guard page, only enable glibc guard page for non-Java threads.
554 return (thr_type == java_thread ? 0 : page_size());
555 }
556
557 // Java thread:
558 //
559 // Low memory addresses
560 // +------------------------+
561 // | |\ JavaThread created by VM does not have glibc
562 // | glibc guard page | - guard, attached Java thread usually has
563 // | |/ 1 page glibc guard.
564 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
565 // | |\
566 // | HotSpot Guard Pages | - red and yellow pages
567 // | |/
568 // +------------------------+ JavaThread::stack_yellow_zone_base()
569 // | |\
570 // | Normal Stack | -
571 // | |/
572 // P2 +------------------------+ Thread::stack_base()
573 //
574 // Non-Java thread:
575 //
576 // Low memory addresses
577 // +------------------------+
578 // | |\
579 // | glibc guard page | - usually 1 page
580 // | |/
581 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
582 // | |\
583 // | Normal Stack | -
584 // | |/
585 // P2 +------------------------+ Thread::stack_base()
586 //
587 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from
588 // pthread_attr_getstack()
589
590 static void current_stack_region(address * bottom, size_t * size) {
591 if (os::Linux::is_initial_thread()) {
592 // initial thread needs special handling because pthread_getattr_np()
593 // may return bogus value.
594 *bottom = os::Linux::initial_thread_stack_bottom();
595 *size = os::Linux::initial_thread_stack_size();
596 } else {
597 pthread_attr_t attr;
598
599 int rslt = pthread_getattr_np(pthread_self(), &attr);
600
601 // JVM needs to know exact stack location, abort if it fails
602 if (rslt != 0) {
603 if (rslt == ENOMEM) {
604 vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "pthread_getattr_np");
605 } else {
606 fatal("pthread_getattr_np failed with errno = %d", rslt);
607 }
608 }
609
610 if (pthread_attr_getstack(&attr, (void **)bottom, size) != 0) {
611 fatal("Can not locate current stack attributes!");
612 }
613
614 pthread_attr_destroy(&attr);
615
616 }
617 assert(os::current_stack_pointer() >= *bottom &&
618 os::current_stack_pointer() < *bottom + *size, "just checking");
619 }
620
621 address os::current_stack_base() {
622 address bottom;
623 size_t size;
624 current_stack_region(&bottom, &size);
625 return (bottom + size);
626 }
627
628 size_t os::current_stack_size() {
629 // stack size includes normal stack and HotSpot guard pages
630 address bottom;
631 size_t size;
632 current_stack_region(&bottom, &size);
633 return size;
634 }
635
636 /////////////////////////////////////////////////////////////////////////////
637 // helper functions for fatal error handler
638
639 void os::print_context(outputStream *st, const void *context) {
640 if (context == NULL) return;
641
642 const ucontext_t* uc = (const ucontext_t*)context;
643
644 st->print_cr("Registers:");
645 st->print("pc =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->nip);
646 st->print("lr =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->link);
647 st->print("ctr=" INTPTR_FORMAT " ", uc->uc_mcontext.regs->ctr);
648 st->cr();
649 for (int i = 0; i < 32; i++) {
650 st->print("r%-2d=" INTPTR_FORMAT " ", i, uc->uc_mcontext.regs->gpr[i]);
651 if (i % 3 == 2) st->cr();
652 }
653 st->cr();
654 st->cr();
655
656 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
657 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
658 print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t));
659 st->cr();
660
661 // Note: it may be unsafe to inspect memory near pc. For example, pc may
662 // point to garbage if entry point in an nmethod is corrupted. Leave
663 // this at the end, and hope for the best.
664 address pc = os::Linux::ucontext_get_pc(uc);
665 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
666 print_hex_dump(st, pc - 64, pc + 64, /*instrsize=*/4);
667 st->cr();
668 }
669
670 void os::print_register_info(outputStream *st, const void *context) {
671 if (context == NULL) return;
672
673 const ucontext_t *uc = (const ucontext_t*)context;
674
675 st->print_cr("Register to memory mapping:");
676 st->cr();
677
678 // this is only for the "general purpose" registers
679 for (int i = 0; i < 32; i++) {
680 st->print("r%-2d=", i);
681 print_location(st, uc->uc_mcontext.regs->gpr[i]);
682 }
683 st->cr();
684 }
685
686 extern "C" {
687 int SpinPause() {
688 return 0;
689 }
690 }
691
692 #ifndef PRODUCT
693 void os::verify_stack_alignment() {
694 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
695 }
696 #endif
697
698 int os::extra_bang_size_in_bytes() {
699 // PPC does not require the additional stack bang.
700 return 0;
701 }