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