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