1 /*
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3  * Copyright (c) 2016, 2018 SAP SE. All rights reserved.
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
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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  *
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25 
26 // This file is organized as os_linux_x86.cpp.
27 
28 // no precompiled headers
29 #include "jvm.h"
30 #include "asm/assembler.inline.hpp"
31 #include "classfile/classLoader.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/icBuffer.hpp"
35 #include "code/nativeInst.hpp"
36 #include "code/vtableStubs.hpp"
37 #include "compiler/disassembler.hpp"
38 #include "interpreter/interpreter.hpp"
39 #include "memory/allocation.inline.hpp"
40 #include "nativeInst_s390.hpp"
41 #include "os_share_linux.hpp"
42 #include "prims/jniFastGetField.hpp"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/frame.inline.hpp"
47 #include "runtime/interfaceSupport.inline.hpp"
48 #include "runtime/java.hpp"
49 #include "runtime/javaCalls.hpp"
50 #include "runtime/mutexLocker.hpp"
51 #include "runtime/osThread.hpp"
52 #include "runtime/sharedRuntime.hpp"
53 #include "runtime/stubRoutines.hpp"
54 #include "runtime/thread.inline.hpp"
55 #include "runtime/timer.hpp"
56 #include "utilities/events.hpp"
57 #include "utilities/debug.hpp"
58 #include "utilities/vmError.hpp"
59 
60 // put OS-includes here
61 # include <sys/types.h>
62 # include <sys/mman.h>
63 # include <pthread.h>
64 # include <signal.h>
65 # include <errno.h>
66 # include <dlfcn.h>
67 # include <stdlib.h>
68 # include <stdio.h>
69 # include <unistd.h>
70 # include <sys/resource.h>
71 # include <pthread.h>
72 # include <sys/stat.h>
73 # include <sys/time.h>
74 # include <sys/utsname.h>
75 # include <sys/socket.h>
76 # include <sys/wait.h>
77 # include <pwd.h>
78 # include <poll.h>
79 # include <ucontext.h>
80 
current_stack_pointer()81 address os::current_stack_pointer() {
82   intptr_t* csp;
83 
84   // Inline assembly for `z_lgr regno(csp), Z_SP' (Z_SP = Z_R15):
85   __asm__ __volatile__ ("lgr %0, 15":"=r"(csp):);
86 
87   assert(((uint64_t)csp & (frame::alignment_in_bytes-1)) == 0, "SP must be aligned");
88   return (address) csp;
89 }
90 
non_memory_address_word()91 char* os::non_memory_address_word() {
92   // Must never look like an address returned by reserve_memory,
93   // even in its subfields (as defined by the CPU immediate fields,
94   // if the CPU splits constants across multiple instructions).
95   return (char*) -1;
96 }
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_s390.hpp.
ucontext_get_pc(const ucontext_t * uc)101 address os::Linux::ucontext_get_pc(const ucontext_t * uc) {
102   return (address)uc->uc_mcontext.psw.addr;
103 }
104 
ucontext_set_pc(ucontext_t * uc,address pc)105 void os::Linux::ucontext_set_pc(ucontext_t * uc, address pc) {
106   uc->uc_mcontext.psw.addr = (unsigned long)pc;
107 }
108 
ucontext_get_lr(const ucontext_t * uc)109 static address ucontext_get_lr(const ucontext_t * uc) {
110   return (address)uc->uc_mcontext.gregs[14/*LINK*/];
111 }
112 
ucontext_get_sp(const ucontext_t * uc)113 intptr_t* os::Linux::ucontext_get_sp(const ucontext_t * uc) {
114   return (intptr_t*)uc->uc_mcontext.gregs[15/*REG_SP*/];
115 }
116 
ucontext_get_fp(const ucontext_t * uc)117 intptr_t* os::Linux::ucontext_get_fp(const ucontext_t * uc) {
118   return NULL;
119 }
120 
fetch_frame_from_context(const void * ucVoid,intptr_t ** ret_sp,intptr_t ** ret_fp)121 ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
122                     intptr_t** ret_sp, intptr_t** ret_fp) {
123 
124   ExtendedPC  epc;
125   const ucontext_t* uc = (const ucontext_t*)ucVoid;
126 
127   if (uc != NULL) {
128     epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
129     if (ret_sp) { *ret_sp = os::Linux::ucontext_get_sp(uc); }
130     if (ret_fp) { *ret_fp = os::Linux::ucontext_get_fp(uc); }
131   } else {
132     // Construct empty ExtendedPC for return value checking.
133     epc = ExtendedPC(NULL);
134     if (ret_sp) { *ret_sp = (intptr_t *)NULL; }
135     if (ret_fp) { *ret_fp = (intptr_t *)NULL; }
136   }
137 
138   return epc;
139 }
140 
fetch_frame_from_context(const void * ucVoid)141 frame os::fetch_frame_from_context(const void* ucVoid) {
142   intptr_t* sp;
143   intptr_t* fp;
144   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
145   return frame(sp, epc.pc());
146 }
147 
get_frame_at_stack_banging_point(JavaThread * thread,ucontext_t * uc,frame * fr)148 bool os::Linux::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
149   address pc = (address) os::Linux::ucontext_get_pc(uc);
150   if (Interpreter::contains(pc)) {
151     // Interpreter performs stack banging after the fixed frame header has
152     // been generated while the compilers perform it before. To maintain
153     // semantic consistency between interpreted and compiled frames, the
154     // method returns the Java sender of the current frame.
155     *fr = os::fetch_frame_from_context(uc);
156     if (!fr->is_first_java_frame()) {
157       assert(fr->safe_for_sender(thread), "Safety check");
158       *fr = fr->java_sender();
159     }
160   } else {
161     // More complex code with compiled code.
162     assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
163     CodeBlob* cb = CodeCache::find_blob(pc);
164     if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
165       // Not sure where the pc points to, fallback to default
166       // stack overflow handling. In compiled code, we bang before
167       // the frame is complete.
168       return false;
169     } else {
170       intptr_t* sp = os::Linux::ucontext_get_sp(uc);
171       address lr = ucontext_get_lr(uc);
172       *fr = frame(sp, lr);
173       if (!fr->is_java_frame()) {
174         assert(fr->safe_for_sender(thread), "Safety check");
175         assert(!fr->is_first_frame(), "Safety check");
176         *fr = fr->java_sender();
177       }
178     }
179   }
180   assert(fr->is_java_frame(), "Safety check");
181   return true;
182 }
183 
get_sender_for_C_frame(frame * fr)184 frame os::get_sender_for_C_frame(frame* fr) {
185   if (*fr->sp() == 0) {
186     // fr is the last C frame.
187     return frame();
188   }
189 
190   // If its not one of our frames, the return pc is saved at gpr14
191   // stack slot. The call_stub stores the return_pc to the stack slot
192   // of gpr10.
193   if ((Interpreter::code() != NULL && Interpreter::contains(fr->pc())) ||
194       (CodeCache::contains(fr->pc()) && !StubRoutines::contains(fr->pc()))) {
195     return frame(fr->sender_sp(), fr->sender_pc());
196   } else {
197     if (StubRoutines::contains(fr->pc())) {
198       StubCodeDesc* desc = StubCodeDesc::desc_for(fr->pc());
199       if (desc && !strcmp(desc->name(),"call_stub")) {
200         return frame(fr->sender_sp(), fr->callstub_sender_pc());
201       } else {
202         return frame(fr->sender_sp(), fr->sender_pc());
203       }
204     } else {
205       return frame(fr->sender_sp(), fr->native_sender_pc());
206     }
207   }
208 }
209 
current_frame()210 frame os::current_frame() {
211   // Expected to return the stack pointer of this method.
212   // But if inlined, returns the stack pointer of our caller!
213   intptr_t* csp = (intptr_t*) *((intptr_t*) os::current_stack_pointer());
214   assert (csp != NULL, "sp should not be NULL");
215   // Pass a dummy pc. This way we don't have to load it from the
216   // stack, since we don't know in which slot we can find it.
217   frame topframe(csp, (address)0x8);
218   if (os::is_first_C_frame(&topframe)) {
219     // Stack is not walkable.
220     return frame();
221   } else {
222     frame senderFrame = os::get_sender_for_C_frame(&topframe);
223     assert(senderFrame.pc() != NULL, "Sender pc should not be NULL");
224     // Return sender of sender of current topframe which hopefully
225     // both have pc != NULL.
226 #ifdef _NMT_NOINLINE_   // Is set in slowdebug builds.
227     // Current_stack_pointer is not inlined, we must pop one more frame.
228     frame tmp = os::get_sender_for_C_frame(&topframe);
229     return os::get_sender_for_C_frame(&tmp);
230 #else
231     return os::get_sender_for_C_frame(&topframe);
232 #endif
233   }
234 }
235 
236 // Utility functions
237 
238 extern "C" JNIEXPORT int
JVM_handle_linux_signal(int sig,siginfo_t * info,void * ucVoid,int abort_if_unrecognized)239 JVM_handle_linux_signal(int sig,
240                         siginfo_t* info,
241                         void* ucVoid,
242                         int abort_if_unrecognized) {
243   ucontext_t* uc = (ucontext_t*) ucVoid;
244 
245   Thread* t = Thread::current_or_null_safe();
246 
247   // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
248   // (no destructors can be run).
249   os::ThreadCrashProtection::check_crash_protection(sig, t);
250 
251   SignalHandlerMark shm(t);
252 
253   // Note: it's not uncommon that JNI code uses signal/sigset to install
254   // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
255   // or have a SIGILL handler when detecting CPU type). When that happens,
256   // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
257   // avoid unnecessary crash when libjsig is not preloaded, try handle signals
258   // that do not require siginfo/ucontext first.
259 
260   if (sig == SIGPIPE) {
261     if (os::Linux::chained_handler(sig, info, ucVoid)) {
262       return true;
263     } else {
264       if (PrintMiscellaneous && (WizardMode || Verbose)) {
265         warning("Ignoring SIGPIPE - see bug 4229104");
266       }
267       return true;
268     }
269   }
270 
271 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
272   if ((sig == SIGSEGV || sig == SIGBUS) && info != NULL && info->si_addr == g_assert_poison) {
273     if (handle_assert_poison_fault(ucVoid, info->si_addr)) {
274       return 1;
275     }
276   }
277 #endif
278 
279   JavaThread* thread = NULL;
280   VMThread* vmthread = NULL;
281   if (os::Linux::signal_handlers_are_installed) {
282     if (t != NULL) {
283       if(t->is_Java_thread()) {
284         thread = (JavaThread*)t;
285       } else if(t->is_VM_thread()) {
286         vmthread = (VMThread *)t;
287       }
288     }
289   }
290 
291   // Moved SafeFetch32 handling outside thread!=NULL conditional block to make
292   // it work if no associated JavaThread object exists.
293   if (uc) {
294     address const pc = os::Linux::ucontext_get_pc(uc);
295     if (pc && StubRoutines::is_safefetch_fault(pc)) {
296       os::Linux::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
297       return true;
298     }
299   }
300 
301   // Decide if this trap can be handled by a stub.
302   address stub    = NULL;
303   address pc      = NULL;  // Pc as retrieved from PSW. Usually points past failing instruction.
304   address trap_pc = NULL;  // Pc of the instruction causing the trap.
305 
306   //%note os_trap_1
307   if (info != NULL && uc != NULL && thread != NULL) {
308     pc = os::Linux::ucontext_get_pc(uc);
309     if (TraceTraps) {
310       tty->print_cr("     pc at " INTPTR_FORMAT, p2i(pc));
311     }
312     if ((unsigned long)(pc - (address)info->si_addr) <= (unsigned long)Assembler::instr_maxlen() ) {
313       trap_pc = (address)info->si_addr;
314       if (TraceTraps) {
315         tty->print_cr("trap_pc at " INTPTR_FORMAT, p2i(trap_pc));
316       }
317     }
318 
319     // Handle ALL stack overflow variations here
320     if (sig == SIGSEGV) {
321       address addr = (address)info->si_addr; // Address causing SIGSEGV, usually mem ref target.
322 
323       // Check if fault address is within thread stack.
324       if (thread->on_local_stack(addr)) {
325         // stack overflow
326         if (thread->in_stack_yellow_reserved_zone(addr)) {
327           if (thread->thread_state() == _thread_in_Java) {
328             if (thread->in_stack_reserved_zone(addr)) {
329               frame fr;
330               if (os::Linux::get_frame_at_stack_banging_point(thread, uc, &fr)) {
331                 assert(fr.is_java_frame(), "Must be a Javac frame");
332                 frame activation =
333                   SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
334                 if (activation.sp() != NULL) {
335                   thread->disable_stack_reserved_zone();
336                   if (activation.is_interpreted_frame()) {
337                     thread->set_reserved_stack_activation((address)activation.fp());
338                   } else {
339                     thread->set_reserved_stack_activation((address)activation.unextended_sp());
340                   }
341                   return 1;
342                 }
343               }
344             }
345             // Throw a stack overflow exception.
346             // Guard pages will be reenabled while unwinding the stack.
347             thread->disable_stack_yellow_reserved_zone();
348             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);
349           } else {
350             // Thread was in the vm or native code. Return and try to finish.
351             thread->disable_stack_yellow_reserved_zone();
352             return 1;
353           }
354         } else if (thread->in_stack_red_zone(addr)) {
355           // Fatal red zone violation.  Disable the guard pages and fall through
356           // to handle_unexpected_exception way down below.
357           thread->disable_stack_red_zone();
358           tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
359 
360           // This is a likely cause, but hard to verify. Let's just print
361           // it as a hint.
362           tty->print_raw_cr("Please check if any of your loaded .so files has "
363                             "enabled executable stack (see man page execstack(8))");
364         } else {
365           // Accessing stack address below sp may cause SEGV if current
366           // thread has MAP_GROWSDOWN stack. This should only happen when
367           // current thread was created by user code with MAP_GROWSDOWN flag
368           // and then attached to VM. See notes in os_linux.cpp.
369           if (thread->osthread()->expanding_stack() == 0) {
370              thread->osthread()->set_expanding_stack();
371              if (os::Linux::manually_expand_stack(thread, addr)) {
372                thread->osthread()->clear_expanding_stack();
373                return 1;
374              }
375              thread->osthread()->clear_expanding_stack();
376           } else {
377              fatal("recursive segv. expanding stack.");
378           }
379         }
380       }
381     }
382 
383     if (thread->thread_state() == _thread_in_Java) {
384       // Java thread running in Java code => find exception handler if any
385       // a fault inside compiled code, the interpreter, or a stub
386 
387       // Handle signal from NativeJump::patch_verified_entry().
388       if (sig == SIGILL && nativeInstruction_at(pc)->is_sigill_zombie_not_entrant()) {
389         if (TraceTraps) {
390           tty->print_cr("trap: zombie_not_entrant (SIGILL)");
391         }
392         stub = SharedRuntime::get_handle_wrong_method_stub();
393       }
394 
395       else if (sig == SIGSEGV &&
396                os::is_poll_address((address)info->si_addr)) {
397         if (TraceTraps) {
398           tty->print_cr("trap: safepoint_poll at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
399         }
400         stub = SharedRuntime::get_poll_stub(pc);
401 
402         // Info->si_addr only points to the page base address, so we
403         // must extract the real si_addr from the instruction and the
404         // ucontext.
405         assert(((NativeInstruction*)pc)->is_safepoint_poll(), "must be safepoint poll");
406         const address real_si_addr = ((NativeInstruction*)pc)->get_poll_address(uc);
407       }
408 
409       // SIGTRAP-based implicit null check in compiled code.
410       else if ((sig == SIGFPE) &&
411                TrapBasedNullChecks &&
412                (trap_pc != NULL) &&
413                Assembler::is_sigtrap_zero_check(trap_pc)) {
414         if (TraceTraps) {
415           tty->print_cr("trap: NULL_CHECK at " INTPTR_FORMAT " (SIGFPE)", p2i(trap_pc));
416         }
417         stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_NULL);
418       }
419 
420       else if (sig == SIGSEGV && ImplicitNullChecks &&
421                CodeCache::contains((void*) pc) &&
422                MacroAssembler::uses_implicit_null_check(info->si_addr)) {
423         if (TraceTraps) {
424           tty->print_cr("trap: null_check at " INTPTR_FORMAT " (SIGSEGV)", p2i(pc));
425         }
426         stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);
427       }
428 
429       // SIGTRAP-based implicit range check in compiled code.
430       else if (sig == SIGFPE && TrapBasedRangeChecks &&
431                (trap_pc != NULL) &&
432                Assembler::is_sigtrap_range_check(trap_pc)) {
433         if (TraceTraps) {
434           tty->print_cr("trap: RANGE_CHECK at " INTPTR_FORMAT " (SIGFPE)", p2i(trap_pc));
435         }
436         stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_NULL);
437       }
438 
439       else if (sig == SIGFPE && info->si_code == FPE_INTDIV) {
440         stub = SharedRuntime::continuation_for_implicit_exception(thread, trap_pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
441       }
442 
443       else if (sig == SIGBUS) {
444         // BugId 4454115: A read from a MappedByteBuffer can fault here if the
445         // underlying file has been truncated. Do not crash the VM in such a case.
446         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
447         CompiledMethod* nm = (cb != NULL) ? cb->as_compiled_method_or_null() : NULL;
448         if (nm != NULL && nm->has_unsafe_access()) {
449           // We don't really need a stub here! Just set the pending exeption and
450           // continue at the next instruction after the faulting read. Returning
451           // garbage from this read is ok.
452           thread->set_pending_unsafe_access_error();
453           uc->uc_mcontext.psw.addr = ((unsigned long)pc) + Assembler::instr_len(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         // when attempting to execute a non-existing instruction.
463         //*(int *) (pc-6)=0; // Patch instruction to 0 to indicate that it causes a SIGILL.
464                              // Flushing of icache is not necessary.
465         stub = pc; // Continue with next instruction.
466       } else if ((sig == SIGFPE) && VM_Version::is_determine_features_test_running()) {
467         // SIGFPE is known to be caused by trying to execute a vector instruction
468         // when the vector facility is installed, but operating system support is missing.
469         VM_Version::reset_has_VectorFacility();
470         stub = pc; // Continue with next instruction.
471       } else if ((thread->thread_state() == _thread_in_vm ||
472                   thread->thread_state() == _thread_in_native) &&
473                  sig == SIGBUS && thread->doing_unsafe_access()) {
474         // We don't really need a stub here! Just set the pending exeption and
475         // continue at the next instruction after the faulting read. Returning
476         // garbage from this read is ok.
477         thread->set_pending_unsafe_access_error();
478         os::Linux::ucontext_set_pc(uc, pc + Assembler::instr_len(pc));
479         return true;
480       }
481     }
482   }
483 
484   if (stub != NULL) {
485     // Save all thread context in case we need to restore it.
486     if (thread != NULL) thread->set_saved_exception_pc(pc);
487     os::Linux::ucontext_set_pc(uc, stub);
488     return true;
489   }
490 
491   // signal-chaining
492   if (os::Linux::chained_handler(sig, info, ucVoid)) {
493     return true;
494   }
495 
496   if (!abort_if_unrecognized) {
497     // caller wants another chance, so give it to him
498     return false;
499   }
500 
501   if (pc == NULL && uc != NULL) {
502     pc = os::Linux::ucontext_get_pc(uc);
503   }
504 
505   // unmask current signal
506   sigset_t newset;
507   sigemptyset(&newset);
508   sigaddset(&newset, sig);
509   sigprocmask(SIG_UNBLOCK, &newset, NULL);
510 
511   // Hand down correct pc for SIGILL, SIGFPE. pc from context
512   // usually points to the instruction after the failing instruction.
513   // Note: this should be combined with the trap_pc handling above,
514   // because it handles the same issue.
515   if (sig == SIGILL || sig == SIGFPE) {
516     pc = (address)info->si_addr;
517   }
518 
519   VMError::report_and_die(t, sig, pc, info, ucVoid);
520 
521   ShouldNotReachHere();
522   return false;
523 }
524 
init_thread_fpu_state(void)525 void os::Linux::init_thread_fpu_state(void) {
526   // Nothing to do on z/Architecture.
527 }
528 
get_fpu_control_word(void)529 int os::Linux::get_fpu_control_word(void) {
530   // Nothing to do on z/Architecture.
531   return 0;
532 }
533 
set_fpu_control_word(int fpu_control)534 void os::Linux::set_fpu_control_word(int fpu_control) {
535   // Nothing to do on z/Architecture.
536 }
537 
538 ////////////////////////////////////////////////////////////////////////////////
539 // thread stack
540 
541 // Minimum usable stack sizes required to get to user code. Space for
542 // HotSpot guard pages is added later.
543 size_t os::Posix::_compiler_thread_min_stack_allowed = (52 DEBUG_ONLY(+ 32)) * K;
544 size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+ 8)) * K;
545 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 32 * K;
546 
547 // Return default stack size for thr_type.
default_stack_size(os::ThreadType thr_type)548 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
549   // Default stack size (compiler thread needs larger stack).
550   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
551   return s;
552 }
553 
554 /////////////////////////////////////////////////////////////////////////////
555 // helper functions for fatal error handler
556 
print_context(outputStream * st,const void * context)557 void os::print_context(outputStream *st, const void *context) {
558   if (context == NULL) return;
559 
560   const ucontext_t* uc = (const ucontext_t*)context;
561 
562   st->print_cr("Processor state:");
563   st->print_cr("----------------");
564   st->print_cr("        ip = " INTPTR_FORMAT " ", uc->uc_mcontext.psw.addr);
565   st->print_cr(" proc mask = " INTPTR_FORMAT " ", uc->uc_mcontext.psw.mask);
566   st->print_cr("   fpc reg = 0x%8.8x "          , uc->uc_mcontext.fpregs.fpc);
567   st->cr();
568 
569   st->print_cr("General Purpose Registers:");
570   st->print_cr("--------------------------");
571   for( int i = 0; i < 16; i+=2 ) {
572     st->print("  r%-2d = " INTPTR_FORMAT "  " ,  i,   uc->uc_mcontext.gregs[i]);
573     st->print("  r%-2d = " INTPTR_FORMAT "  |",  i+1, uc->uc_mcontext.gregs[i+1]);
574     st->print("  r%-2d = %23.1ld  "           ,  i,   uc->uc_mcontext.gregs[i]);
575     st->print("  r%-2d = %23.1ld  "           ,  i+1, uc->uc_mcontext.gregs[i+1]);
576     st->cr();
577   }
578   st->cr();
579 
580   st->print_cr("Access Registers:");
581   st->print_cr("-----------------");
582   for( int i = 0; i < 16; i+=2 ) {
583     st->print("  ar%-2d = 0x%8.8x  ", i,   uc->uc_mcontext.aregs[i]);
584     st->print("  ar%-2d = 0x%8.8x  ", i+1, uc->uc_mcontext.aregs[i+1]);
585     st->cr();
586   }
587   st->cr();
588 
589   st->print_cr("Float Registers:");
590   st->print_cr("----------------");
591   for (int i = 0; i < 16; i += 2) {
592     st->print("  fr%-2d = " INTPTR_FORMAT "  " , i,   (int64_t)(uc->uc_mcontext.fpregs.fprs[i].d));
593     st->print("  fr%-2d = " INTPTR_FORMAT "  |", i+1, (int64_t)(uc->uc_mcontext.fpregs.fprs[i+1].d));
594     st->print("  fr%-2d = %23.15e  "           , i,   (uc->uc_mcontext.fpregs.fprs[i].d));
595     st->print("  fr%-2d = %23.15e  "           , i+1, (uc->uc_mcontext.fpregs.fprs[i+1].d));
596     st->cr();
597   }
598   st->cr();
599   st->cr();
600 
601   intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
602   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", p2i(sp));
603   print_hex_dump(st, (address)sp, (address)(sp + 128), sizeof(intptr_t));
604   st->cr();
605 
606   // Note: it may be unsafe to inspect memory near pc. For example, pc may
607   // point to garbage if entry point in an nmethod is corrupted. Leave
608   // this at the end, and hope for the best.
609   address pc = os::Linux::ucontext_get_pc(uc);
610   print_instructions(st, pc, /*intrsize=*/4);
611   st->cr();
612 }
613 
print_register_info(outputStream * st,const void * context)614 void os::print_register_info(outputStream *st, const void *context) {
615   if (context == NULL) return;
616 
617   const ucontext_t *uc = (const ucontext_t*)context;
618 
619   st->print_cr("Register to memory mapping:");
620   st->cr();
621 
622   st->print("pc ="); print_location(st, (intptr_t)uc->uc_mcontext.psw.addr);
623   for (int i = 0; i < 16; i++) {
624     st->print("r%-2d=", i);
625     print_location(st, uc->uc_mcontext.gregs[i]);
626   }
627   st->cr();
628 }
629 
630 #ifndef PRODUCT
verify_stack_alignment()631 void os::verify_stack_alignment() {
632 }
633 #endif
634 
extra_bang_size_in_bytes()635 int os::extra_bang_size_in_bytes() {
636   // z/Architecture does not require the additional stack bang.
637   return 0;
638 }
639