1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2012, 2018 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 "jvm.h"
28 #include "asm/assembler.inline.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/icBuffer.hpp"
34 #include "code/vtableStubs.hpp"
35 #include "interpreter/interpreter.hpp"
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_misc.hpp"
41 #include "runtime/arguments.hpp"
42 #include "runtime/extendedPC.hpp"
43 #include "runtime/frame.inline.hpp"
44 #include "runtime/interfaceSupport.inline.hpp"
45 #include "runtime/java.hpp"
46 #include "runtime/javaCalls.hpp"
47 #include "runtime/mutexLocker.hpp"
48 #include "runtime/osThread.hpp"
49 #include "runtime/safepointMechanism.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/debug.hpp"
55 #include "utilities/events.hpp"
56 #include "utilities/vmError.hpp"
57
58 // put OS-includes here
59 # include <sys/types.h>
60 # include <sys/mman.h>
61 # include <pthread.h>
62 # include <signal.h>
63 # include <errno.h>
64 # include <dlfcn.h>
65 # include <stdlib.h>
66 # include <stdio.h>
67 # include <unistd.h>
68 # include <sys/resource.h>
69 # include <pthread.h>
70 # include <sys/stat.h>
71 # include <sys/time.h>
72 # include <sys/utsname.h>
73 # include <sys/socket.h>
74 # include <sys/wait.h>
75 # include <pwd.h>
76 # include <poll.h>
77 # include <ucontext.h>
78
79
80 address os::current_stack_pointer() {
81 intptr_t* csp;
82
83 // inline assembly `mr regno(csp), R1_SP':
84 __asm__ __volatile__ ("mr %0, 1":"=r"(csp):);
85
86 return (address) csp;
87 }
88
89 char* os::non_memory_address_word() {
90 // Must never look like an address returned by reserve_memory,
91 // even in its subfields (as defined by the CPU immediate fields,
92 // if the CPU splits constants across multiple instructions).
93
94 return (char*) -1;
95 }
96
97 // Frame information (pc, sp, fp) retrieved via ucontext
98 // always looks like a C-frame according to the frame
99 // conventions in frame_ppc64.hpp.
100 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
101 // On powerpc64, ucontext_t is not selfcontained but contains
102 // a pointer to an optional substructure (mcontext_t.regs) containing the volatile
103 // registers - NIP, among others.
104 // This substructure may or may not be there depending where uc came from:
105 // - if uc was handed over as the argument to a sigaction handler, a pointer to the
106 // substructure was provided by the kernel when calling the signal handler, and
107 // regs->nip can be accessed.
108 // - if uc was filled by getcontext(), it is undefined - getcontext() does not fill
109 // it because the volatile registers are not needed to make setcontext() work.
110 // Hopefully it was zero'd out beforehand.
111 guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_get_pc in sigaction context");
112 return (address)uc->uc_mcontext.regs->nip;
113 }
114
115 // modify PC in ucontext.
116 // Note: Only use this for an ucontext handed down to a signal handler. See comment
117 // in ucontext_get_pc.
118 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
119 guarantee(uc->uc_mcontext.regs != NULL, "only use ucontext_set_pc in sigaction context");
120 uc->uc_mcontext.regs->nip = (unsigned long)pc;
121 }
122
123 static address ucontext_get_lr(const ucontext_t * uc) {
124 return (address)uc->uc_mcontext.regs->link;
125 }
126
127 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
128 return (intptr_t*)uc->uc_mcontext.regs->gpr[1/*REG_SP*/];
129 }
130
131 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
132 return NULL;
133 }
134
135 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
136 intptr_t** ret_sp, intptr_t** ret_fp) {
137
138 ExtendedPC epc;
139 const ucontext_t* uc = (const ucontext_t*)ucVoid;
140
141 if (uc != NULL) {
142 epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
143 if (ret_sp) *ret_sp = os::Linux::ucontext_get_sp(uc);
144 if (ret_fp) *ret_fp = os::Linux::ucontext_get_fp(uc);
145 } else {
146 // construct empty ExtendedPC for return value checking
147 epc = ExtendedPC(NULL);
148 if (ret_sp) *ret_sp = (intptr_t *)NULL;
149 if (ret_fp) *ret_fp = (intptr_t *)NULL;
150 }
151
152 return epc;
153 }
154
155 frame os::fetch_frame_from_context(const void* ucVoid) {
156 intptr_t* sp;
157 intptr_t* fp;
158 ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
159 return frame(sp, epc.pc());
160 }
161
162 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
163 address pc = (address) os::Linux::ucontext_get_pc(uc);
164 if (Interpreter::contains(pc)) {
165 // Interpreter performs stack banging after the fixed frame header has
166 // been generated while the compilers perform it before. To maintain
167 // semantic consistency between interpreted and compiled frames, the
168 // method returns the Java sender of the current frame.
169 *fr = os::fetch_frame_from_context(uc);
170 if (!fr->is_first_java_frame()) {
171 assert(fr->safe_for_sender(thread), "Safety check");
172 *fr = fr->java_sender();
173 }
174 } else {
175 // More complex code with compiled code.
176 assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
177 CodeBlob* cb = CodeCache::find_blob(pc);
178 if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
179 // Not sure where the pc points to, fallback to default
180 // stack overflow handling. In compiled code, we bang before
181 // the frame is complete.
182 return false;
183 } else {
184 intptr_t* sp = os::Linux::ucontext_get_sp(uc);
185 address lr = ucontext_get_lr(uc);
186 *fr = frame(sp, lr);
187 if (!fr->is_java_frame()) {
188 assert(fr->safe_for_sender(thread), "Safety check");
189 assert(!fr->is_first_frame(), "Safety check");
190 *fr = fr->java_sender();
191 }
192 }
193 }
194 assert(fr->is_java_frame(), "Safety check");
195 return true;
196 }
197
198 frame os::get_sender_for_C_frame(frame* fr) {
199 if (*fr->sp() == 0) {
200 // fr is the last C frame
201 return frame(NULL, NULL);
202 }
203 return frame(fr->sender_sp(), fr->sender_pc());
204 }
205
206
207 frame os::current_frame() {
208 intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer());
209 // hack.
210 frame topframe(csp, (address)0x8);
211 // Return sender of sender of current topframe which hopefully
212 // both have pc != NULL.
213 frame tmp = os::get_sender_for_C_frame(&topframe);
214 return os::get_sender_for_C_frame(&tmp);
215 }
216
217 // Utility functions
218
219 extern "C" JNIEXPORT int
220 JVM_handle_linux_signal(int sig,
221 siginfo_t* info,
222 void* ucVoid,
223 int abort_if_unrecognized) {
224 ucontext_t* uc = (ucontext_t*) ucVoid;
225
226 Thread* t = Thread::current_or_null_safe();
227
228 SignalHandlerMark shm(t);
229
230 // Note: it's not uncommon that JNI code uses signal/sigset to install
231 // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
232 // or have a SIGILL handler when detecting CPU type). When that happens,
233 // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
234 // avoid unnecessary crash when libjsig is not preloaded, try handle signals
235 // that do not require siginfo/ucontext first.
236
237 if (sig == SIGPIPE) {
238 if (os::Linux::chained_handler(sig, info, ucVoid)) {
239 return true;
240 } else {
241 // Ignoring SIGPIPE - see bugs 4229104
242 return true;
243 }
244 }
245
246 // Make the signal handler transaction-aware by checking the existence of a
247 // second (transactional) context with MSR TS bits active. If the signal is
248 // caught during a transaction, then just return to the HTM abort handler.
249 // Please refer to Linux kernel document powerpc/transactional_memory.txt,
250 // section "Signals".
251 if (uc && uc->uc_link) {
252 ucontext_t* second_uc = uc->uc_link;
253
254 // MSR TS bits are 29 and 30 (Power ISA, v2.07B, Book III-S, pp. 857-858,
255 // 3.2.1 "Machine State Register"), however note that ISA notation for bit
256 // numbering is MSB 0, so for normal bit numbering (LSB 0) they come to be
257 // bits 33 and 34. It's not related to endianness, just a notation matter.
258 if (second_uc->uc_mcontext.regs->msr & 0x600000000) {
259 if (TraceTraps) {
260 tty->print_cr("caught signal in transaction, "
261 "ignoring to jump to abort handler");
262 }
263 // Return control to the HTM abort handler.
264 return true;
265 }
266 }
267
268 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
269 if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
270 handle_assert_poison_fault(ucVoid, info->si_addr);
271 return 1;
272 }
273 #endif
274
275 JavaThread* thread = NULL;
276 VMThread* vmthread = NULL;
277 if (os::Linux::signal_handlers_are_installed) {
278 if (t != NULL) {
279 if(t->is_Java_thread()) {
280 thread = (JavaThread*)t;
281 } else if(t->is_VM_thread()) {
282 vmthread = (VMThread *)t;
283 }
284 }
285 }
286
287 // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
288 // it work if no associated JavaThread object exists.
289 if (uc) {
290 address const pc = os::Linux::ucontext_get_pc(uc);
291 if (pc && StubRoutines::is_safefetch_fault(pc)) {
292 os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
293 return true;
294 }
295 }
296
297 // decide if this trap can be handled by a stub
298 address stub = NULL;
299 address pc = NULL;
300
301 //%note os_trap_1
302 if (info != NULL && uc != NULL && thread != NULL) {
303 pc = (address) os::Linux::ucontext_get_pc(uc);
304
305 // Handle ALL stack overflow variations here
306 if (sig == SIGSEGV) {
307 // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see
308 // comment below). Use get_stack_bang_address instead of si_addr.
309 address addr = ((NativeInstruction*)pc)->get_stack_bang_address(uc);
310
311 // Check if fault address is within thread stack.
312 if (thread->on_local_stack(addr)) {
313 // stack overflow
314 if (thread->in_stack_yellow_reserved_zone(addr)) {
315 if (thread->thread_state() == _thread_in_Java) {
316 if (thread->in_stack_reserved_zone(addr)) {
317 frame fr;
318 if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
319 assert(fr.is_java_frame(), "Must be a Javac frame");
320 frame activation =
321 SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
322 if (activation.sp() != NULL) {
323 thread->disable_stack_reserved_zone();
324 if (activation.is_interpreted_frame()) {
325 thread->set_reserved_stack_activation((address)activation.fp());
326 } else {
327 thread->set_reserved_stack_activation((address)activation.unextended_sp());
328 }
329 return 1;
330 }
331 }
332 }
333 // Throw a stack overflow exception.
334 // Guard pages will be reenabled while unwinding the stack.
335 thread->disable_stack_yellow_reserved_zone();
336 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
337 } else {
338 // Thread was in the vm or native code. Return and try to finish.
339 thread->disable_stack_yellow_reserved_zone();
340 return 1;
341 }
342 } else if (thread->in_stack_red_zone(addr)) {
343 // Fatal red zone violation. Disable the guard pages and fall through
344 // to handle_unexpected_exception way down below.
345 thread->disable_stack_red_zone();
346 tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
347
348 // This is a likely cause, but hard to verify. Let's just print
349 // it as a hint.
350 tty->print_raw_cr("Please check if any of your loaded .so files has "
351 "enabled executable stack (see man page execstack(8))");
352 } else {
353 // Accessing stack address below sp may cause SEGV if current
354 // thread has MAP_GROWSDOWN stack. This should only happen when
355 // current thread was created by user code with MAP_GROWSDOWN flag
356 // and then attached to VM. See notes in os_linux.cpp.
357 if (thread->osthread()->expanding_stack() == 0) {
358 thread->osthread()->set_expanding_stack();
359 if (os::Linux::manually_expand_stack(thread, addr)) {
360 thread->osthread()->clear_expanding_stack();
361 return 1;
362 }
363 thread->osthread()->clear_expanding_stack();
364 } else {
365 fatal("recursive segv. expanding stack.");
366 }
367 }
368 }
369 }
370
371 if (thread->thread_state() == _thread_in_Java) {
372 // Java thread running in Java code => find exception handler if any
373 // a fault inside compiled code, the interpreter, or a stub
374
375 // A VM-related SIGILL may only occur if we are not in the zero page.
376 // On AIX, we get a SIGILL if we jump to 0x0 or to somewhere else
377 // in the zero page, because it is filled with 0x0. We ignore
378 // explicit SIGILLs in the zero page.
379 if (sig == SIGILL && (pc < (address) 0x200)) {
380 if (TraceTraps) {
381 tty->print_raw_cr("SIGILL happened inside zero page.");
382 }
383 goto report_and_die;
384 }
385
386 CodeBlob *cb = NULL;
387 // Handle signal from NativeJump::patch_verified_entry().
388 if (( TrapBasedNotEntrantChecks && sig == SIGTRAP && nativeInstruction_at(pc)->is_sigtrap_zombie_not_entrant()) ||
389 (!TrapBasedNotEntrantChecks && sig == SIGILL && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant())) {
390 if (TraceTraps) {
391 tty->print_cr("trap: zombie_not_entrant (%s)", (sig == SIGTRAP) ? "SIGTRAP" : "SIGILL");
392 }
393 stub = SharedRuntime::get_handle_wrong_method_stub();
394 }
395
396 else if (sig == ((SafepointMechanism::uses_thread_local_poll() && USE_POLL_BIT_ONLY) ? SIGTRAP : SIGSEGV) &&
397 // A linux-ppc64 kernel before 2.6.6 doesn't set si_addr on some segfaults
398 // in 64bit mode (cf. http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.6),
399 // especially when we try to read from the safepoint polling page. So the check
400 // (address)info->si_addr == os::get_standard_polling_page()
401 // doesn't work for us. We use:
402 ((NativeInstruction*)pc)->is_safepoint_poll() &&
403 CodeCache::contains((void*) pc) &&
404 ((cb = CodeCache::find_blob(pc)) != NULL) &&
405 cb->is_compiled()) {
406 if (TraceTraps) {
407 tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (%s)", p2i(pc),
408 (SafepointMechanism::uses_thread_local_poll() && USE_POLL_BIT_ONLY) ? "SIGTRAP" : "SIGSEGV");
409 }
410 stub = SharedRuntime::get_poll_stub(pc);
411 }
412
413 // SIGTRAP-based ic miss check in compiled code.
414 else if (sig == SIGTRAP && TrapBasedICMissChecks &&
415 nativeInstruction_at(pc)->is_sigtrap_ic_miss_check()) {
416 if (TraceTraps) {
417 tty->print_cr("trap: ic_miss_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
418 }
419 stub = SharedRuntime::get_ic_miss_stub();
420 }
421
422 // SIGTRAP-based implicit null check in compiled code.
423 else if (sig == SIGTRAP && TrapBasedNullChecks &&
424 nativeInstruction_at(pc)->is_sigtrap_null_check()) {
425 if (TraceTraps) {
426 tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
427 }
428 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
429 }
430
431 // SIGSEGV-based implicit null check in compiled code.
432 else if (sig == SIGSEGV && ImplicitNullChecks &&
433 CodeCache::contains((void*) pc) &&
434 MacroAssembler::uses_implicit_null_check(info->si_addr)) {
435 if (TraceTraps) {
436 tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
437 }
438 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
439 }
440
441 #ifdef COMPILER2
442 // SIGTRAP-based implicit range check in compiled code.
443 else if (sig == SIGTRAP && TrapBasedRangeChecks &&
444 nativeInstruction_at(pc)->is_sigtrap_range_check()) {
445 if (TraceTraps) {
446 tty->print_cr("trap: range_check at " INTPTR_FORMAT " (SIGTRAP)", p2i(pc));
447 }
448 stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
449 }
450 #endif
451 else if (sig == SIGBUS) {
452 // BugId 4454115: A read from a MappedByteBuffer can fault here if the
453 // underlying file has been truncated. Do not crash the VM in such a case.
454 CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
455 CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
456 if (nm != NULL && nm->has_unsafe_access()) {
457 address next_pc = pc + 4;
458 next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
459 os::Linux::ucontext_set_pc(uc, next_pc);
460 return true;
461 }
462 }
463 }
464
465 else { // thread->thread_state() != _thread_in_Java
466 if (sig == SIGILL && VM_Version::is_determine_features_test_running()) {
467 // SIGILL must be caused by VM_Version::determine_features().
468 *(int *)pc = 0; // patch instruction to 0 to indicate that it causes a SIGILL,
469 // flushing of icache is not necessary.
470 stub = pc + 4; // continue with next instruction.
471 }
472 else if (thread->thread_state() == _thread_in_vm &&
473 sig == SIGBUS && thread->doing_unsafe_access()) {
474 address next_pc = pc + 4;
475 next_pc = SharedRuntime::handle_unsafe_access(thread, next_pc);
476 os::Linux::ucontext_set_pc(uc, pc + 4);
477 return true;
478 }
479 }
480
481 // Check to see if we caught the safepoint code in the
482 // process of write protecting the memory serialization page.
483 // It write enables the page immediately after protecting it
484 // so we can just return to retry the write.
485 if ((sig == SIGSEGV) &&
486 // Si_addr may not be valid due to a bug in the linux-ppc64 kernel (see comment above).
487 // Use is_memory_serialization instead of si_addr.
488 ((NativeInstruction*)pc)->is_memory_serialization(thread, ucVoid)) {
489 // Synchronization problem in the pseudo memory barrier code (bug id 6546278)
490 // Block current thread until the memory serialize page permission restored.
491 os::block_on_serialize_page_trap();
492 return true;
493 }
494 }
495
496 if (stub != NULL) {
497 // Save all thread context in case we need to restore it.
498 if (thread != NULL) thread->set_saved_exception_pc(pc);
499 os::Linux::ucontext_set_pc(uc, stub);
500 return true;
501 }
502
503 // signal-chaining
504 if (os::Linux::chained_handler(sig, info, ucVoid)) {
505 return true;
506 }
507
508 if (!abort_if_unrecognized) {
509 // caller wants another chance, so give it to him
510 return false;
511 }
512
513 if (pc == NULL && uc != NULL) {
514 pc = os::Linux::ucontext_get_pc(uc);
515 }
516
517 report_and_die:
518 // unmask current signal
519 sigset_t newset;
520 sigemptyset(&newset);
521 sigaddset(&newset, sig);
522 sigprocmask(SIG_UNBLOCK, &newset, NULL);
523
524 VMError::report_and_die(t, sig, pc, info, ucVoid);
525
526 ShouldNotReachHere();
527 return false;
528 }
529
530 void os::Linux::init_thread_fpu_state(void) {
531 // Disable FP exceptions.
532 __asm__ __volatile__ ("mtfsfi 6,0");
533 }
534
535 int os::Linux::get_fpu_control_word(void) {
536 // x86 has problems with FPU precision after pthread_cond_timedwait().
537 // nothing to do on ppc64.
538 return 0;
539 }
540
541 void os::Linux::set_fpu_control_word(int fpu_control) {
542 // x86 has problems with FPU precision after pthread_cond_timedwait().
543 // nothing to do on ppc64.
544 }
545
546 ////////////////////////////////////////////////////////////////////////////////
547 // thread stack
548
549 // Minimum usable stack sizes required to get to user code. Space for
550 // HotSpot guard pages is added later.
551 size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
552 size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
553 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 64 * K;
554
555 // Return default stack size for thr_type.
556 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
557 // Default stack size (compiler thread needs larger stack).
558 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
559 return s;
560 }
561
562 /////////////////////////////////////////////////////////////////////////////
563 // helper functions for fatal error handler
564
565 void os::print_context(outputStream *st, const void *context) {
566 if (context == NULL) return;
567
568 const ucontext_t* uc = (const ucontext_t*)context;
569
570 st->print_cr("Registers:");
571 st->print("pc =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->nip);
572 st->print("lr =" INTPTR_FORMAT " ", uc->uc_mcontext.regs->link);
573 st->print("ctr=" INTPTR_FORMAT " ", uc->uc_mcontext.regs->ctr);
574 st->cr();
575 for (int i = 0; i < 32; i++) {
576 st->print("r%-2d=" INTPTR_FORMAT " ", i, uc->uc_mcontext.regs->gpr[i]);
577 if (i % 3 == 2) st->cr();
578 }
579 st->cr();
580 st->cr();
581
582 intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
583 st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
584 print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t));
585 st->cr();
586
587 // Note: it may be unsafe to inspect memory near pc. For example, pc may
588 // point to garbage if entry point in an nmethod is corrupted. Leave
589 // this at the end, and hope for the best.
590 address pc = os::Linux::ucontext_get_pc(uc);
591 st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
592 print_hex_dump(st, pc - 64, pc + 64, /*instrsize=*/4);
593 st->cr();
594 }
595
596 void os::print_register_info(outputStream *st, const void *context) {
597 if (context == NULL) return;
598
599 const ucontext_t *uc = (const ucontext_t*)context;
600
601 st->print_cr("Register to memory mapping:");
602 st->cr();
603
604 st->print("pc ="); print_location(st, (intptr_t)uc->uc_mcontext.regs->nip);
605 st->print("lr ="); print_location(st, (intptr_t)uc->uc_mcontext.regs->link);
606 st->print("ctr ="); print_location(st, (intptr_t)uc->uc_mcontext.regs->ctr);
607 for (int i = 0; i < 32; i++) {
608 st->print("r%-2d=", i);
609 print_location(st, uc->uc_mcontext.regs->gpr[i]);
610 }
611 st->cr();
612 }
613
614 extern "C" {
615 int SpinPause() {
616 return 0;
617 }
618 }
619
620 #ifndef PRODUCT
621 void os::verify_stack_alignment() {
622 assert(((intptr_t)os::current_stack_pointer() & (StackAlignmentInBytes-1)) == 0, "incorrect stack alignment");
623 }
624 #endif
625
626 int os::extra_bang_size_in_bytes() {
627 // PPC does not require the additional stack bang.
628 return 0;
629 }