1/*
2 * Copyright (c) 1999, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25// no precompiled headers
26#include "asm/macroAssembler.hpp"
27#include "classfile/classLoader.hpp"
28#include "classfile/systemDictionary.hpp"
29#include "classfile/vmSymbols.hpp"
30#include "code/codeCache.hpp"
31#include "code/icBuffer.hpp"
32#include "code/vtableStubs.hpp"
33#include "interpreter/interpreter.hpp"
34#include "jvm_linux.h"
35#include "memory/allocation.inline.hpp"
36#include "nativeInst_sparc.hpp"
37#include "os_share_linux.hpp"
38#include "prims/jniFastGetField.hpp"
39#include "prims/jvm.h"
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.hpp"
45#include "runtime/java.hpp"
46#include "runtime/javaCalls.hpp"
47#include "runtime/mutexLocker.hpp"
48#include "runtime/osThread.hpp"
49#include "runtime/sharedRuntime.hpp"
50#include "runtime/stubRoutines.hpp"
51#include "runtime/thread.inline.hpp"
52#include "runtime/timer.hpp"
53#include "utilities/events.hpp"
54#include "utilities/vmError.hpp"
55
56// Linux/Sparc has rather obscure naming of registers in sigcontext
57// different between 32 and 64 bits
58#define SIG_PC(x) ((x)->sigc_regs.tpc)
59#define SIG_NPC(x) ((x)->sigc_regs.tnpc)
60#define SIG_REGS(x) ((x)->sigc_regs)
61
62// those are to reference registers in sigcontext
63enum {
64  CON_G0 = 0,
65  CON_G1,
66  CON_G2,
67  CON_G3,
68  CON_G4,
69  CON_G5,
70  CON_G6,
71  CON_G7,
72  CON_O0,
73  CON_O1,
74  CON_O2,
75  CON_O3,
76  CON_O4,
77  CON_O5,
78  CON_O6,
79  CON_O7,
80};
81
82// For Forte Analyzer AsyncGetCallTrace profiling support - thread is
83// currently interrupted by SIGPROF.
84// os::Solaris::fetch_frame_from_ucontext() tries to skip nested
85// signal frames. Currently we don't do that on Linux, so it's the
86// same as os::fetch_frame_from_context().
87ExtendedPC os::Linux::fetch_frame_from_ucontext(Thread* thread,
88                                                const ucontext_t* uc,
89                                                intptr_t** ret_sp,
90                                                intptr_t** ret_fp) {
91  assert(thread != NULL, "just checking");
92  assert(ret_sp != NULL, "just checking");
93  assert(ret_fp != NULL, "just checking");
94
95  return os::fetch_frame_from_context(uc, ret_sp, ret_fp);
96}
97
98ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
99                                        intptr_t** ret_sp,
100                                        intptr_t** ret_fp) {
101  const ucontext_t* uc = (const ucontext_t*) ucVoid;
102  ExtendedPC  epc;
103
104  if (uc != NULL) {
105    epc = ExtendedPC(os::Linux::ucontext_get_pc(uc));
106    if (ret_sp) {
107      *ret_sp = os::Linux::ucontext_get_sp(uc);
108    }
109    if (ret_fp) {
110      *ret_fp = (intptr_t*)NULL;
111    }
112  } else {
113    // construct empty ExtendedPC for return value checking
114    epc = ExtendedPC(NULL);
115    if (ret_sp) {
116      *ret_sp = (intptr_t*) NULL;
117    }
118    if (ret_fp) {
119      *ret_fp = (intptr_t*) NULL;
120    }
121  }
122
123  return epc;
124}
125
126frame os::fetch_frame_from_context(const void* ucVoid) {
127  intptr_t* sp;
128  ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, NULL);
129  return frame(sp, frame::unpatchable, epc.pc());
130}
131
132frame os::get_sender_for_C_frame(frame* fr) {
133  return frame(fr->sender_sp(), frame::unpatchable, fr->sender_pc());
134}
135
136frame os::current_frame() {
137  intptr_t* sp = StubRoutines::Sparc::flush_callers_register_windows_func()();
138  frame myframe(sp, frame::unpatchable,
139                CAST_FROM_FN_PTR(address, os::current_frame));
140  if (os::is_first_C_frame(&myframe)) {
141    // stack is not walkable
142    return frame(NULL, frame::unpatchable, NULL);
143  } else {
144    return os::get_sender_for_C_frame(&myframe);
145  }
146}
147
148address os::current_stack_pointer() {
149  register void *sp __asm__ ("sp");
150  return (address)sp;
151}
152
153char* os::non_memory_address_word() {
154  // Must never look like an address returned by reserve_memory,
155  // even in its subfields (as defined by the CPU immediate fields,
156  // if the CPU splits constants across multiple instructions).
157  // On SPARC, 0 != %hi(any real address), because there is no
158  // allocation in the first 1Kb of the virtual address space.
159  return (char*) 0;
160}
161
162void os::initialize_thread(Thread* thr) {}
163
164void os::print_context(outputStream *st, const void *context) {
165  if (context == NULL) return;
166
167  const ucontext_t* uc = (const ucontext_t*)context;
168  sigcontext* sc = (sigcontext*)context;
169  st->print_cr("Registers:");
170
171  st->print_cr(" G1=" INTPTR_FORMAT " G2=" INTPTR_FORMAT
172               " G3=" INTPTR_FORMAT " G4=" INTPTR_FORMAT,
173               SIG_REGS(sc).u_regs[CON_G1],
174               SIG_REGS(sc).u_regs[CON_G2],
175               SIG_REGS(sc).u_regs[CON_G3],
176               SIG_REGS(sc).u_regs[CON_G4]);
177  st->print_cr(" G5=" INTPTR_FORMAT " G6=" INTPTR_FORMAT
178               " G7=" INTPTR_FORMAT " Y=0x%x",
179               SIG_REGS(sc).u_regs[CON_G5],
180               SIG_REGS(sc).u_regs[CON_G6],
181               SIG_REGS(sc).u_regs[CON_G7],
182               SIG_REGS(sc).y);
183  st->print_cr(" O0=" INTPTR_FORMAT " O1=" INTPTR_FORMAT
184               " O2=" INTPTR_FORMAT " O3=" INTPTR_FORMAT,
185               SIG_REGS(sc).u_regs[CON_O0],
186               SIG_REGS(sc).u_regs[CON_O1],
187               SIG_REGS(sc).u_regs[CON_O2],
188               SIG_REGS(sc).u_regs[CON_O3]);
189  st->print_cr(" O4=" INTPTR_FORMAT " O5=" INTPTR_FORMAT
190               " O6=" INTPTR_FORMAT " O7=" INTPTR_FORMAT,
191               SIG_REGS(sc).u_regs[CON_O4],
192               SIG_REGS(sc).u_regs[CON_O5],
193               SIG_REGS(sc).u_regs[CON_O6],
194               SIG_REGS(sc).u_regs[CON_O7]);
195
196
197  intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
198  st->print_cr(" L0=" INTPTR_FORMAT " L1=" INTPTR_FORMAT
199               " L2=" INTPTR_FORMAT " L3=" INTPTR_FORMAT,
200               sp[L0->sp_offset_in_saved_window()],
201               sp[L1->sp_offset_in_saved_window()],
202               sp[L2->sp_offset_in_saved_window()],
203               sp[L3->sp_offset_in_saved_window()]);
204  st->print_cr(" L4=" INTPTR_FORMAT " L5=" INTPTR_FORMAT
205               " L6=" INTPTR_FORMAT " L7=" INTPTR_FORMAT,
206               sp[L4->sp_offset_in_saved_window()],
207               sp[L5->sp_offset_in_saved_window()],
208               sp[L6->sp_offset_in_saved_window()],
209               sp[L7->sp_offset_in_saved_window()]);
210  st->print_cr(" I0=" INTPTR_FORMAT " I1=" INTPTR_FORMAT
211               " I2=" INTPTR_FORMAT " I3=" INTPTR_FORMAT,
212               sp[I0->sp_offset_in_saved_window()],
213               sp[I1->sp_offset_in_saved_window()],
214               sp[I2->sp_offset_in_saved_window()],
215               sp[I3->sp_offset_in_saved_window()]);
216  st->print_cr(" I4=" INTPTR_FORMAT " I5=" INTPTR_FORMAT
217               " I6=" INTPTR_FORMAT " I7=" INTPTR_FORMAT,
218               sp[I4->sp_offset_in_saved_window()],
219               sp[I5->sp_offset_in_saved_window()],
220               sp[I6->sp_offset_in_saved_window()],
221               sp[I7->sp_offset_in_saved_window()]);
222
223  st->print_cr(" PC=" INTPTR_FORMAT " nPC=" INTPTR_FORMAT,
224               SIG_PC(sc),
225               SIG_NPC(sc));
226  st->cr();
227  st->cr();
228
229  st->print_cr("Top of Stack: (sp=" INTPTR_FORMAT ")", p2i(sp));
230  print_hex_dump(st, (address)sp, (address)(sp + 32), sizeof(intptr_t));
231  st->cr();
232
233  // Note: it may be unsafe to inspect memory near pc. For example, pc may
234  // point to garbage if entry point in an nmethod is corrupted. Leave
235  // this at the end, and hope for the best.
236  address pc = os::Linux::ucontext_get_pc(uc);
237  st->print_cr("Instructions: (pc=" INTPTR_FORMAT ")", p2i(pc));
238  print_hex_dump(st, pc - 32, pc + 32, sizeof(char));
239}
240
241
242void os::print_register_info(outputStream *st, const void *context) {
243  if (context == NULL) return;
244
245  const ucontext_t *uc = (const ucontext_t*)context;
246  const sigcontext* sc = (const sigcontext*)context;
247  intptr_t *sp = (intptr_t *)os::Linux::ucontext_get_sp(uc);
248
249  st->print_cr("Register to memory mapping:");
250  st->cr();
251
252  // this is only for the "general purpose" registers
253  st->print("G1="); print_location(st, SIG_REGS(sc).u_regs[CON_G1]);
254  st->print("G2="); print_location(st, SIG_REGS(sc).u_regs[CON_G2]);
255  st->print("G3="); print_location(st, SIG_REGS(sc).u_regs[CON_G3]);
256  st->print("G4="); print_location(st, SIG_REGS(sc).u_regs[CON_G4]);
257  st->print("G5="); print_location(st, SIG_REGS(sc).u_regs[CON_G5]);
258  st->print("G6="); print_location(st, SIG_REGS(sc).u_regs[CON_G6]);
259  st->print("G7="); print_location(st, SIG_REGS(sc).u_regs[CON_G7]);
260  st->cr();
261
262  st->print("O0="); print_location(st, SIG_REGS(sc).u_regs[CON_O0]);
263  st->print("O1="); print_location(st, SIG_REGS(sc).u_regs[CON_O1]);
264  st->print("O2="); print_location(st, SIG_REGS(sc).u_regs[CON_O2]);
265  st->print("O3="); print_location(st, SIG_REGS(sc).u_regs[CON_O3]);
266  st->print("O4="); print_location(st, SIG_REGS(sc).u_regs[CON_O4]);
267  st->print("O5="); print_location(st, SIG_REGS(sc).u_regs[CON_O5]);
268  st->print("O6="); print_location(st, SIG_REGS(sc).u_regs[CON_O6]);
269  st->print("O7="); print_location(st, SIG_REGS(sc).u_regs[CON_O7]);
270  st->cr();
271
272  st->print("L0="); print_location(st, sp[L0->sp_offset_in_saved_window()]);
273  st->print("L1="); print_location(st, sp[L1->sp_offset_in_saved_window()]);
274  st->print("L2="); print_location(st, sp[L2->sp_offset_in_saved_window()]);
275  st->print("L3="); print_location(st, sp[L3->sp_offset_in_saved_window()]);
276  st->print("L4="); print_location(st, sp[L4->sp_offset_in_saved_window()]);
277  st->print("L5="); print_location(st, sp[L5->sp_offset_in_saved_window()]);
278  st->print("L6="); print_location(st, sp[L6->sp_offset_in_saved_window()]);
279  st->print("L7="); print_location(st, sp[L7->sp_offset_in_saved_window()]);
280  st->cr();
281
282  st->print("I0="); print_location(st, sp[I0->sp_offset_in_saved_window()]);
283  st->print("I1="); print_location(st, sp[I1->sp_offset_in_saved_window()]);
284  st->print("I2="); print_location(st, sp[I2->sp_offset_in_saved_window()]);
285  st->print("I3="); print_location(st, sp[I3->sp_offset_in_saved_window()]);
286  st->print("I4="); print_location(st, sp[I4->sp_offset_in_saved_window()]);
287  st->print("I5="); print_location(st, sp[I5->sp_offset_in_saved_window()]);
288  st->print("I6="); print_location(st, sp[I6->sp_offset_in_saved_window()]);
289  st->print("I7="); print_location(st, sp[I7->sp_offset_in_saved_window()]);
290  st->cr();
291}
292
293
294address os::Linux::ucontext_get_pc(const ucontext_t* uc) {
295  return (address) SIG_PC((sigcontext*)uc);
296}
297
298void os::Linux::ucontext_set_pc(ucontext_t* uc, address pc) {
299  sigcontext* ctx = (sigcontext*) uc;
300  SIG_PC(ctx)  = (intptr_t)pc;
301  SIG_NPC(ctx) = (intptr_t)(pc+4);
302}
303
304intptr_t* os::Linux::ucontext_get_sp(const ucontext_t *uc) {
305  return (intptr_t*)
306    ((intptr_t)SIG_REGS((sigcontext*)uc).u_regs[CON_O6] + STACK_BIAS);
307}
308
309// not used on Sparc
310intptr_t* os::Linux::ucontext_get_fp(const ucontext_t *uc) {
311  ShouldNotReachHere();
312  return NULL;
313}
314
315// Utility functions
316
317inline static bool checkPrefetch(sigcontext* uc, address pc) {
318  if (StubRoutines::is_safefetch_fault(pc)) {
319    os::Linux::ucontext_set_pc((ucontext_t*)uc, StubRoutines::continuation_for_safefetch_fault(pc));
320    return true;
321  }
322  return false;
323}
324
325inline static bool checkOverflow(sigcontext* uc,
326                                 address pc,
327                                 address addr,
328                                 JavaThread* thread,
329                                 address* stub) {
330  // check if fault address is within thread stack
331  if (thread->on_local_stack(addr)) {
332    // stack overflow
333    if (thread->in_stack_yellow_reserved_zone(addr)) {
334      thread->disable_stack_yellow_reserved_zone();
335      if (thread->thread_state() == _thread_in_Java) {
336        // Throw a stack overflow exception.  Guard pages will be reenabled
337        // while unwinding the stack.
338        *stub =
339          SharedRuntime::continuation_for_implicit_exception(thread,
340                                                             pc,
341                                                             SharedRuntime::STACK_OVERFLOW);
342      } else {
343        // Thread was in the vm or native code.  Return and try to finish.
344        return true;
345      }
346    } else if (thread->in_stack_red_zone(addr)) {
347      // Fatal red zone violation.  Disable the guard pages and fall through
348      // to handle_unexpected_exception way down below.
349      thread->disable_stack_red_zone();
350      tty->print_raw_cr("An irrecoverable stack overflow has occurred.");
351
352      // This is a likely cause, but hard to verify. Let's just print
353      // it as a hint.
354      tty->print_raw_cr("Please check if any of your loaded .so files has "
355                        "enabled executable stack (see man page execstack(8))");
356    } else {
357      // Accessing stack address below sp may cause SEGV if current
358      // thread has MAP_GROWSDOWN stack. This should only happen when
359      // current thread was created by user code with MAP_GROWSDOWN flag
360      // and then attached to VM. See notes in os_linux.cpp.
361      if (thread->osthread()->expanding_stack() == 0) {
362        thread->osthread()->set_expanding_stack();
363        if (os::Linux::manually_expand_stack(thread, addr)) {
364          thread->osthread()->clear_expanding_stack();
365          return true;
366        }
367        thread->osthread()->clear_expanding_stack();
368      } else {
369        fatal("recursive segv. expanding stack.");
370      }
371    }
372  }
373  return false;
374}
375
376inline static bool checkPollingPage(address pc, address fault, address* stub) {
377  if (fault == os::get_polling_page()) {
378    *stub = SharedRuntime::get_poll_stub(pc);
379    return true;
380  }
381  return false;
382}
383
384inline static bool checkByteBuffer(address pc, address npc, JavaThread * thread, address* stub) {
385  // BugId 4454115: A read from a MappedByteBuffer can fault
386  // here if the underlying file has been truncated.
387  // Do not crash the VM in such a case.
388  CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
389  CompiledMethod* nm = cb->as_compiled_method_or_null();
390  if (nm != NULL && nm->has_unsafe_access()) {
391    *stub = SharedRuntime::handle_unsafe_access(thread, npc);
392    return true;
393  }
394  return false;
395}
396
397inline static bool checkVerifyOops(address pc, address fault, address* stub) {
398  if (pc >= MacroAssembler::_verify_oop_implicit_branch[0]
399      && pc <  MacroAssembler::_verify_oop_implicit_branch[1] ) {
400    *stub     =  MacroAssembler::_verify_oop_implicit_branch[2];
401    warning("fixed up memory fault in +VerifyOops at address "
402            INTPTR_FORMAT, p2i(fault));
403    return true;
404  }
405  return false;
406}
407
408inline static bool checkFPFault(address pc, int code,
409                                JavaThread* thread, address* stub) {
410  if (code == FPE_INTDIV || code == FPE_FLTDIV) {
411    *stub =
412      SharedRuntime::
413      continuation_for_implicit_exception(thread,
414                                          pc,
415                                          SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
416    return true;
417  }
418  return false;
419}
420
421inline static bool checkNullPointer(address pc, intptr_t fault,
422                                    JavaThread* thread, address* stub) {
423  if (!MacroAssembler::needs_explicit_null_check(fault)) {
424    // Determination of interpreter/vtable stub/compiled code null
425    // exception
426    *stub =
427      SharedRuntime::
428      continuation_for_implicit_exception(thread, pc,
429                                          SharedRuntime::IMPLICIT_NULL);
430    return true;
431  }
432  return false;
433}
434
435inline static bool checkFastJNIAccess(address pc, address* stub) {
436  address addr = JNI_FastGetField::find_slowcase_pc(pc);
437  if (addr != (address)-1) {
438    *stub = addr;
439    return true;
440  }
441  return false;
442}
443
444inline static bool checkSerializePage(JavaThread* thread, address addr) {
445  return os::is_memory_serialize_page(thread, addr);
446}
447
448inline static bool checkZombie(sigcontext* uc, address* pc, address* stub) {
449  if (nativeInstruction_at(*pc)->is_zombie()) {
450    // zombie method (ld [%g0],%o7 instruction)
451    *stub = SharedRuntime::get_handle_wrong_method_stub();
452
453    // At the stub it needs to look like a call from the caller of this
454    // method (not a call from the segv site).
455    *pc = (address)SIG_REGS(uc).u_regs[CON_O7];
456    return true;
457  }
458  return false;
459}
460
461inline static bool checkICMiss(sigcontext* uc, address* pc, address* stub) {
462#ifdef COMPILER2
463  if (nativeInstruction_at(*pc)->is_ic_miss_trap()) {
464#ifdef ASSERT
465#ifdef TIERED
466    CodeBlob* cb = CodeCache::find_blob_unsafe(*pc);
467    assert(cb->is_compiled_by_c2(), "Wrong compiler");
468#endif // TIERED
469#endif // ASSERT
470    // Inline cache missed and user trap "Tne G0+ST_RESERVED_FOR_USER_0+2" taken.
471    *stub = SharedRuntime::get_ic_miss_stub();
472    // At the stub it needs to look like a call from the caller of this
473    // method (not a call from the segv site).
474    *pc = (address)SIG_REGS(uc).u_regs[CON_O7];
475    return true;
476  }
477#endif  // COMPILER2
478  return false;
479}
480
481extern "C" JNIEXPORT int
482JVM_handle_linux_signal(int sig,
483                        siginfo_t* info,
484                        void* ucVoid,
485                        int abort_if_unrecognized) {
486  // in fact this isn't ucontext_t* at all, but struct sigcontext*
487  // but Linux porting layer uses ucontext_t, so to minimize code change
488  // we cast as needed
489  ucontext_t* ucFake = (ucontext_t*) ucVoid;
490  sigcontext* uc = (sigcontext*)ucVoid;
491
492  Thread* t = Thread::current_or_null_safe();
493
494  // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
495  // (no destructors can be run)
496  os::ThreadCrashProtection::check_crash_protection(sig, t);
497
498  SignalHandlerMark shm(t);
499
500  // Note: it's not uncommon that JNI code uses signal/sigset to install
501  // then restore certain signal handler (e.g. to temporarily block SIGPIPE,
502  // or have a SIGILL handler when detecting CPU type). When that happens,
503  // JVM_handle_linux_signal() might be invoked with junk info/ucVoid. To
504  // avoid unnecessary crash when libjsig is not preloaded, try handle signals
505  // that do not require siginfo/ucontext first.
506
507  if (sig == SIGPIPE || sig == SIGXFSZ) {
508    // allow chained handler to go first
509    if (os::Linux::chained_handler(sig, info, ucVoid)) {
510      return true;
511    } else {
512      // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
513      return true;
514    }
515  }
516
517  JavaThread* thread = NULL;
518  VMThread* vmthread = NULL;
519  if (os::Linux::signal_handlers_are_installed) {
520    if (t != NULL ){
521      if(t->is_Java_thread()) {
522        thread = (JavaThread*)t;
523      }
524      else if(t->is_VM_thread()){
525        vmthread = (VMThread *)t;
526      }
527    }
528  }
529
530  // decide if this trap can be handled by a stub
531  address stub = NULL;
532  address pc = NULL;
533  address npc = NULL;
534
535  //%note os_trap_1
536  if (info != NULL && uc != NULL && thread != NULL) {
537    pc = address(SIG_PC(uc));
538    npc = address(SIG_NPC(uc));
539
540    // Check to see if we caught the safepoint code in the
541    // process of write protecting the memory serialization page.
542    // It write enables the page immediately after protecting it
543    // so we can just return to retry the write.
544    if ((sig == SIGSEGV) && checkSerializePage(thread, (address)info->si_addr)) {
545      // Block current thread until the memory serialize page permission restored.
546      os::block_on_serialize_page_trap();
547      return 1;
548    }
549
550    if (checkPrefetch(uc, pc)) {
551      return 1;
552    }
553
554    // Handle ALL stack overflow variations here
555    if (sig == SIGSEGV) {
556      if (checkOverflow(uc, pc, (address)info->si_addr, thread, &stub)) {
557        return 1;
558      }
559    }
560
561    if (sig == SIGBUS &&
562        thread->thread_state() == _thread_in_vm &&
563        thread->doing_unsafe_access()) {
564      stub = SharedRuntime::handle_unsafe_access(thread, npc);
565    }
566
567    if (thread->thread_state() == _thread_in_Java) {
568      do {
569        // Java thread running in Java code => find exception handler if any
570        // a fault inside compiled code, the interpreter, or a stub
571
572        if ((sig == SIGSEGV) && checkPollingPage(pc, (address)info->si_addr, &stub)) {
573          break;
574        }
575
576        if ((sig == SIGBUS) && checkByteBuffer(pc, npc, thread, &stub)) {
577          break;
578        }
579
580        if ((sig == SIGSEGV || sig == SIGBUS) &&
581            checkVerifyOops(pc, (address)info->si_addr, &stub)) {
582          break;
583        }
584
585        if ((sig == SIGSEGV) && checkZombie(uc, &pc, &stub)) {
586          break;
587        }
588
589        if ((sig == SIGILL) && checkICMiss(uc, &pc, &stub)) {
590          break;
591        }
592
593        if ((sig == SIGFPE) && checkFPFault(pc, info->si_code, thread, &stub)) {
594          break;
595        }
596
597        if ((sig == SIGSEGV) &&
598            checkNullPointer(pc, (intptr_t)info->si_addr, thread, &stub)) {
599          break;
600        }
601      } while (0);
602
603      // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in
604      // and the heap gets shrunk before the field access.
605      if ((sig == SIGSEGV) || (sig == SIGBUS)) {
606        checkFastJNIAccess(pc, &stub);
607      }
608    }
609
610    if (stub != NULL) {
611      // save all thread context in case we need to restore it
612      thread->set_saved_exception_pc(pc);
613      thread->set_saved_exception_npc(npc);
614      os::Linux::ucontext_set_pc((ucontext_t*)uc, stub);
615      return true;
616    }
617  }
618
619  // signal-chaining
620  if (os::Linux::chained_handler(sig, info, ucVoid)) {
621    return true;
622  }
623
624  if (!abort_if_unrecognized) {
625    // caller wants another chance, so give it to him
626    return false;
627  }
628
629  if (pc == NULL && uc != NULL) {
630    pc = os::Linux::ucontext_get_pc((const ucontext_t*)uc);
631  }
632
633  // unmask current signal
634  sigset_t newset;
635  sigemptyset(&newset);
636  sigaddset(&newset, sig);
637  sigprocmask(SIG_UNBLOCK, &newset, NULL);
638
639  VMError::report_and_die(t, sig, pc, info, ucVoid);
640
641  ShouldNotReachHere();
642  return false;
643}
644
645void os::Linux::init_thread_fpu_state(void) {
646  // Nothing to do
647}
648
649int os::Linux::get_fpu_control_word() {
650  return 0;
651}
652
653void os::Linux::set_fpu_control_word(int fpu) {
654  // nothing
655}
656
657bool os::is_allocatable(size_t bytes) {
658  return true;
659}
660
661///////////////////////////////////////////////////////////////////////////////
662// thread stack
663
664// Minimum usable stack sizes required to get to user code. Space for
665// HotSpot guard pages is added later.
666size_t os::Posix::_compiler_thread_min_stack_allowed = 64 * K;
667size_t os::Posix::_java_thread_min_stack_allowed = 64 * K;
668size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
669
670// return default stack size for thr_type
671size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
672  // default stack size (compiler thread needs larger stack)
673  size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);
674  return s;
675}
676
677#ifndef PRODUCT
678void os::verify_stack_alignment() {
679}
680#endif
681
682int os::extra_bang_size_in_bytes() {
683  // SPARC does not require the additional stack bang.
684  return 0;
685}
686