Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 // no precompiled headers

 #include "asm/macroAssembler.hpp"

 #include "classfile/classLoader.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "classfile/vmSymbols.hpp"

 #include "code/icBuffer.hpp"

 #include "code/vtableStubs.hpp"

 #include "interpreter/interpreter.hpp"

 #include "jvm_bsd.h"

 #include "memory/allocation.inline.hpp"

 #include "mutex_bsd.inline.hpp"

 #include "os_share_bsd.hpp"

 #include "prims/jniFastGetField.hpp"

 #include "prims/jvm.h"

 #include "prims/jvm_misc.hpp"

 #include "runtime/arguments.hpp"

 #include "runtime/extendedPC.hpp"

 #include "runtime/frame.inline.hpp"

 #include "runtime/interfaceSupport.hpp"

 #include "runtime/java.hpp"

 #include "runtime/javaCalls.hpp"

 #include "runtime/mutexLocker.hpp"

 #include "runtime/osThread.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "runtime/stubRoutines.hpp"

 #include "runtime/thread.inline.hpp"

 #include "runtime/timer.hpp"

 #include "utilities/events.hpp"

 #include "utilities/vmError.hpp"

 // put OS-includes here

 # include <sys/types.h>

 # include <sys/mman.h>

 # include <pthread.h>

 # include <signal.h>

 # include <errno.h>

 # include <dlfcn.h>

 # include <stdlib.h>

 # include <stdio.h>

 # include <unistd.h>

 # include <sys/resource.h>

 # include <pthread.h>

 # include <sys/stat.h>

 # include <sys/time.h>

 # include <sys/utsname.h>

 # include <sys/socket.h>

 # include <sys/wait.h>

 # include <pwd.h>

 # include <poll.h>

 #ifndef __OpenBSD__

 # include <ucontext.h>

 #endif

 #if !defined(__APPLE__) && !defined(__NetBSD__)

 # include <pthread_np.h>

 #endif

 #ifdef AMD64

 #define SPELL_REG_SP "rsp"

 #define SPELL_REG_FP "rbp"

 #else

 #define SPELL_REG_SP "esp"

 #define SPELL_REG_FP "ebp"

 #endif // AMD64

 #ifdef __FreeBSD__

 # define context_trapno uc_mcontext.mc_trapno

 # ifdef AMD64

 #  define context_pc uc_mcontext.mc_rip

 #  define context_sp uc_mcontext.mc_rsp

 #  define context_fp uc_mcontext.mc_rbp

 #  define context_rip uc_mcontext.mc_rip

 #  define context_rsp uc_mcontext.mc_rsp

 #  define context_rbp uc_mcontext.mc_rbp

 #  define context_rax uc_mcontext.mc_rax

 #  define context_rbx uc_mcontext.mc_rbx

 #  define context_rcx uc_mcontext.mc_rcx

 #  define context_rdx uc_mcontext.mc_rdx

 #  define context_rsi uc_mcontext.mc_rsi

 #  define context_rdi uc_mcontext.mc_rdi

 #  define context_r8  uc_mcontext.mc_r8

 #  define context_r9  uc_mcontext.mc_r9

 #  define context_r10 uc_mcontext.mc_r10

 #  define context_r11 uc_mcontext.mc_r11

 #  define context_r12 uc_mcontext.mc_r12

 #  define context_r13 uc_mcontext.mc_r13

 #  define context_r14 uc_mcontext.mc_r14

 #  define context_r15 uc_mcontext.mc_r15

 #  define context_flags uc_mcontext.mc_flags

 #  define context_err uc_mcontext.mc_err

 # else

 #  define context_pc uc_mcontext.mc_eip

 #  define context_sp uc_mcontext.mc_esp

 #  define context_fp uc_mcontext.mc_ebp

 #  define context_eip uc_mcontext.mc_eip

 #  define context_esp uc_mcontext.mc_esp

 #  define context_eax uc_mcontext.mc_eax

 #  define context_ebx uc_mcontext.mc_ebx

 #  define context_ecx uc_mcontext.mc_ecx

 #  define context_edx uc_mcontext.mc_edx

 #  define context_ebp uc_mcontext.mc_ebp

 #  define context_esi uc_mcontext.mc_esi

 #  define context_edi uc_mcontext.mc_edi

 #  define context_eflags uc_mcontext.mc_eflags

 #  define context_trapno uc_mcontext.mc_trapno

 # endif

 #endif

 #ifdef __APPLE__

 # if __DARWIN_UNIX03 && (MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5)

   // 10.5 UNIX03 member name prefixes

   #define DU3_PREFIX(s, m) __ ## s.__ ## m

 # else

   #define DU3_PREFIX(s, m) s ## . ## m

 # endif

 # ifdef AMD64

 #  define context_pc context_rip

 #  define context_sp context_rsp

 #  define context_fp context_rbp

 #  define context_rip uc_mcontext->DU3_PREFIX(ss,rip)

 #  define context_rsp uc_mcontext->DU3_PREFIX(ss,rsp)

 #  define context_rax uc_mcontext->DU3_PREFIX(ss,rax)

 #  define context_rbx uc_mcontext->DU3_PREFIX(ss,rbx)

 #  define context_rcx uc_mcontext->DU3_PREFIX(ss,rcx)

 #  define context_rdx uc_mcontext->DU3_PREFIX(ss,rdx)

 #  define context_rbp uc_mcontext->DU3_PREFIX(ss,rbp)

 #  define context_rsi uc_mcontext->DU3_PREFIX(ss,rsi)

 #  define context_rdi uc_mcontext->DU3_PREFIX(ss,rdi)

 #  define context_r8  uc_mcontext->DU3_PREFIX(ss,r8)

 #  define context_r9  uc_mcontext->DU3_PREFIX(ss,r9)

 #  define context_r10 uc_mcontext->DU3_PREFIX(ss,r10)

 #  define context_r11 uc_mcontext->DU3_PREFIX(ss,r11)

 #  define context_r12 uc_mcontext->DU3_PREFIX(ss,r12)

 #  define context_r13 uc_mcontext->DU3_PREFIX(ss,r13)

 #  define context_r14 uc_mcontext->DU3_PREFIX(ss,r14)

 #  define context_r15 uc_mcontext->DU3_PREFIX(ss,r15)

 #  define context_flags uc_mcontext->DU3_PREFIX(ss,rflags)

 #  define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)

 #  define context_err uc_mcontext->DU3_PREFIX(es,err)

 # else

 #  define context_pc context_eip

 #  define context_sp context_esp

 #  define context_fp context_ebp

 #  define context_eip uc_mcontext->DU3_PREFIX(ss,eip)

 #  define context_esp uc_mcontext->DU3_PREFIX(ss,esp)

 #  define context_eax uc_mcontext->DU3_PREFIX(ss,eax)

 #  define context_ebx uc_mcontext->DU3_PREFIX(ss,ebx)

 #  define context_ecx uc_mcontext->DU3_PREFIX(ss,ecx)

 #  define context_edx uc_mcontext->DU3_PREFIX(ss,edx)

 #  define context_ebp uc_mcontext->DU3_PREFIX(ss,ebp)

 #  define context_esi uc_mcontext->DU3_PREFIX(ss,esi)

 #  define context_edi uc_mcontext->DU3_PREFIX(ss,edi)

 #  define context_eflags uc_mcontext->DU3_PREFIX(ss,eflags)

 #  define context_trapno uc_mcontext->DU3_PREFIX(es,trapno)

 # endif

 #endif

 #ifdef __OpenBSD__

 # define context_trapno sc_trapno

 # ifdef AMD64

 #  define context_pc sc_rip

 #  define context_sp sc_rsp

 #  define context_fp sc_rbp

 #  define context_rip sc_rip

 #  define context_rsp sc_rsp

 #  define context_rbp sc_rbp

 #  define context_rax sc_rax

 #  define context_rbx sc_rbx

 #  define context_rcx sc_rcx

 #  define context_rdx sc_rdx

 #  define context_rsi sc_rsi

 #  define context_rdi sc_rdi

 #  define context_r8  sc_r8

 #  define context_r9  sc_r9

 #  define context_r10 sc_r10

 #  define context_r11 sc_r11

 #  define context_r12 sc_r12

 #  define context_r13 sc_r13

 #  define context_r14 sc_r14

 #  define context_r15 sc_r15

 #  define context_flags sc_rflags

 #  define context_err sc_err

 # else

 #  define context_pc sc_eip

 #  define context_sp sc_esp

 #  define context_fp sc_ebp

 #  define context_eip sc_eip

 #  define context_esp sc_esp

 #  define context_eax sc_eax

 #  define context_ebx sc_ebx

 #  define context_ecx sc_ecx

 #  define context_edx sc_edx

 #  define context_ebp sc_ebp

 #  define context_esi sc_esi

 #  define context_edi sc_edi

 #  define context_eflags sc_eflags

 #  define context_trapno sc_trapno

 # endif

 #endif

 #ifdef __NetBSD__

 # define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]

 # ifdef AMD64

 #  define __register_t __greg_t

 #  define context_pc uc_mcontext.__gregs[_REG_RIP]

 #  define context_sp uc_mcontext.__gregs[_REG_URSP]

 #  define context_fp uc_mcontext.__gregs[_REG_RBP]

 #  define context_rip uc_mcontext.__gregs[_REG_RIP]

 #  define context_rsp uc_mcontext.__gregs[_REG_URSP]

 #  define context_rax uc_mcontext.__gregs[_REG_RAX]

 #  define context_rbx uc_mcontext.__gregs[_REG_RBX]

 #  define context_rcx uc_mcontext.__gregs[_REG_RCX]

 #  define context_rdx uc_mcontext.__gregs[_REG_RDX]

 #  define context_rbp uc_mcontext.__gregs[_REG_RBP]

 #  define context_rsi uc_mcontext.__gregs[_REG_RSI]

 #  define context_rdi uc_mcontext.__gregs[_REG_RDI]

 #  define context_r8  uc_mcontext.__gregs[_REG_R8]

 #  define context_r9  uc_mcontext.__gregs[_REG_R9]

 #  define context_r10 uc_mcontext.__gregs[_REG_R10]

 #  define context_r11 uc_mcontext.__gregs[_REG_R11]

 #  define context_r12 uc_mcontext.__gregs[_REG_R12]

 #  define context_r13 uc_mcontext.__gregs[_REG_R13]

 #  define context_r14 uc_mcontext.__gregs[_REG_R14]

 #  define context_r15 uc_mcontext.__gregs[_REG_R15]

 #  define context_flags uc_mcontext.__gregs[_REG_RFL]

 #  define context_err uc_mcontext.__gregs[_REG_ERR]

 # else

 #  define context_pc uc_mcontext.__gregs[_REG_EIP]

 #  define context_sp uc_mcontext.__gregs[_REG_UESP]

 #  define context_fp uc_mcontext.__gregs[_REG_EBP]

 #  define context_eip uc_mcontext.__gregs[_REG_EIP]

 #  define context_esp uc_mcontext.__gregs[_REG_UESP]

 #  define context_eax uc_mcontext.__gregs[_REG_EAX]

 #  define context_ebx uc_mcontext.__gregs[_REG_EBX]

 #  define context_ecx uc_mcontext.__gregs[_REG_ECX]

 #  define context_edx uc_mcontext.__gregs[_REG_EDX]

 #  define context_ebp uc_mcontext.__gregs[_REG_EBP]

 #  define context_esi uc_mcontext.__gregs[_REG_ESI]

 #  define context_edi uc_mcontext.__gregs[_REG_EDI]

 #  define context_eflags uc_mcontext.__gregs[_REG_EFL]

 #  define context_trapno uc_mcontext.__gregs[_REG_TRAPNO]

 # endif

 #endif

 address os::current_stack_pointer() {

 #if defined(__clang__) || defined(__llvm__)

   register void *esp;

   __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));

   return (address) esp;

 #elif defined(SPARC_WORKS)

   register void *esp;

   __asm__("mov %%"SPELL_REG_SP", %0":"=r"(esp));

   return (address) ((char*)esp + sizeof(long)*2);

 #else

   register void *esp __asm__ (SPELL_REG_SP);

   return (address) esp;

 #endif

 }

 char* os::non_memory_address_word() {

   // Must never look like an address returned by reserve_memory,

   // even in its subfields (as defined by the CPU immediate fields,

   // if the CPU splits constants across multiple instructions).

   return (char*) -1;

 }

 void os::initialize_thread(Thread* thr) {

 // Nothing to do.

 }

 address os::Bsd::ucontext_get_pc(ucontext_t * uc) {

   return (address)uc->context_pc;

 }

 intptr_t* os::Bsd::ucontext_get_sp(ucontext_t * uc) {

   return (intptr_t*)uc->context_sp;

 }

 intptr_t* os::Bsd::ucontext_get_fp(ucontext_t * uc) {

   return (intptr_t*)uc->context_fp;

 }

 // For Forte Analyzer AsyncGetCallTrace profiling support - thread

 // is currently interrupted by SIGPROF.

 // os::Solaris::fetch_frame_from_ucontext() tries to skip nested signal

 // frames. Currently we don't do that on Bsd, so it's the same as

 // os::fetch_frame_from_context().

 ExtendedPC os::Bsd::fetch_frame_from_ucontext(Thread* thread,

   ucontext_t* uc, intptr_t** ret_sp, intptr_t** ret_fp) {

   assert(thread != NULL, "just checking");

   assert(ret_sp != NULL, "just checking");

   assert(ret_fp != NULL, "just checking");

   return os::fetch_frame_from_context(uc, ret_sp, ret_fp);

 }

 ExtendedPC os::fetch_frame_from_context(void* ucVoid,

                     intptr_t** ret_sp, intptr_t** ret_fp) {

   ExtendedPC  epc;

   ucontext_t* uc = (ucontext_t*)ucVoid;

   if (uc != NULL) {

     epc = ExtendedPC(os::Bsd::ucontext_get_pc(uc));

     if (ret_sp) *ret_sp = os::Bsd::ucontext_get_sp(uc);

     if (ret_fp) *ret_fp = os::Bsd::ucontext_get_fp(uc);

   } else {

     // construct empty ExtendedPC for return value checking

     epc = ExtendedPC(NULL);

     if (ret_sp) *ret_sp = (intptr_t *)NULL;

     if (ret_fp) *ret_fp = (intptr_t *)NULL;

   }

   return epc;

 }

 frame os::fetch_frame_from_context(void* ucVoid) {

   intptr_t* sp;

   intptr_t* fp;

   ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);

   return frame(sp, fp, epc.pc());

 }

 // By default, gcc always save frame pointer (%ebp/%rbp) on stack. It may get

 // turned off by -fomit-frame-pointer,

 frame os::get_sender_for_C_frame(frame* fr) {

   return frame(fr->sender_sp(), fr->link(), fr->sender_pc());

 }

 intptr_t* _get_previous_fp() {

 #if defined(SPARC_WORKS) || defined(__clang__) || defined(__llvm__)

   register intptr_t **ebp;

   __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));

 #else

   register intptr_t **ebp __asm__ (SPELL_REG_FP);

 #endif

   return (intptr_t*) *ebp;   // we want what it points to.

 }

 frame os::current_frame() {

   intptr_t* fp = _get_previous_fp();

   frame myframe((intptr_t*)os::current_stack_pointer(),

                 (intptr_t*)fp,

                 CAST_FROM_FN_PTR(address, os::current_frame));

   if (os::is_first_C_frame(&myframe)) {

     // stack is not walkable

     return frame();

   } else {

     return os::get_sender_for_C_frame(&myframe);

   }

 }

 // Utility functions

 // From IA32 System Programming Guide

 enum {

   trap_page_fault = 0xE

 };

 extern "C" void Fetch32PFI () ;

 extern "C" void Fetch32Resume () ;

 #ifdef AMD64

 extern "C" void FetchNPFI () ;

 extern "C" void FetchNResume () ;

 #endif // AMD64

 extern "C" JNIEXPORT int

 JVM_handle_bsd_signal(int sig,

                         siginfo_t* info,

                         void* ucVoid,

                         int abort_if_unrecognized) {

   ucontext_t* uc = (ucontext_t*) ucVoid;

   Thread* t = ThreadLocalStorage::get_thread_slow();

   SignalHandlerMark shm(t);

   // Note: it's not uncommon that JNI code uses signal/sigset to install

   // then restore certain signal handler (e.g. to temporarily block SIGPIPE,

   // or have a SIGILL handler when detecting CPU type). When that happens,

   // JVM_handle_bsd_signal() might be invoked with junk info/ucVoid. To

   // avoid unnecessary crash when libjsig is not preloaded, try handle signals

   // that do not require siginfo/ucontext first.

   if (sig == SIGPIPE || sig == SIGXFSZ) {

     // allow chained handler to go first

     if (os::Bsd::chained_handler(sig, info, ucVoid)) {

       return true;

     } else {

       if (PrintMiscellaneous && (WizardMode || Verbose)) {

         char buf[64];

         warning("Ignoring %s - see bugs 4229104 or 646499219",

                 os::exception_name(sig, buf, sizeof(buf)));

       }

       return true;

     }

   }

   JavaThread* thread = NULL;

   VMThread* vmthread = NULL;

   if (os::Bsd::signal_handlers_are_installed) {

     if (t != NULL ){

       if(t->is_Java_thread()) {

         thread = (JavaThread*)t;

       }

       else if(t->is_VM_thread()){

         vmthread = (VMThread *)t;

       }

     }

   }

 /*

   NOTE: does not seem to work on bsd.

   if (info == NULL || info->si_code <= 0 || info->si_code == SI_NOINFO) {

     // can't decode this kind of signal

     info = NULL;

   } else {

     assert(sig == info->si_signo, "bad siginfo");

   }

 */

   // decide if this trap can be handled by a stub

   address stub = NULL;

   address pc          = NULL;

   //%note os_trap_1

   if (info != NULL && uc != NULL && thread != NULL) {

     pc = (address) os::Bsd::ucontext_get_pc(uc);

     if (pc == (address) Fetch32PFI) {

        uc->context_pc = intptr_t(Fetch32Resume) ;

        return 1 ;

     }

 #ifdef AMD64

     if (pc == (address) FetchNPFI) {

        uc->context_pc = intptr_t (FetchNResume) ;

        return 1 ;

     }

 #endif // AMD64

     // Handle ALL stack overflow variations here

     if (sig == SIGSEGV || sig == SIGBUS) {

       address addr = (address) info->si_addr;

       // check if fault address is within thread stack

       if (addr < thread->stack_base() &&

           addr >= thread->stack_base() - thread->stack_size()) {

         // stack overflow

         if (thread->in_stack_yellow_zone(addr)) {

           thread->disable_stack_yellow_zone();

           if (thread->thread_state() == _thread_in_Java) {

             // Throw a stack overflow exception.  Guard pages will be reenabled

             // while unwinding the stack.

             stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::STACK_OVERFLOW);

           } else {

             // Thread was in the vm or native code.  Return and try to finish.

             return 1;

           }

         } else if (thread->in_stack_red_zone(addr)) {

           // Fatal red zone violation.  Disable the guard pages and fall through

           // to handle_unexpected_exception way down below.

           thread->disable_stack_red_zone();

           tty->print_raw_cr("An irrecoverable stack overflow has occurred.");

         }

       }

     }

     // We test if stub is already set (by the stack overflow code

     // above) so it is not overwritten by the code that follows. This

     // check is not required on other platforms, because on other

     // platforms we check for SIGSEGV only or SIGBUS only, where here

     // we have to check for both SIGSEGV and SIGBUS.

     if (thread->thread_state() == _thread_in_Java && stub == NULL) {

       // Java thread running in Java code => find exception handler if any

       // a fault inside compiled code, the interpreter, or a stub

       if ((sig == SIGSEGV || sig == SIGBUS) && os::is_poll_address((address)info->si_addr)) {

         stub = SharedRuntime::get_poll_stub(pc);

 #if defined(__APPLE__)

       // 32-bit Darwin reports a SIGBUS for nearly all memory access exceptions.

       // 64-bit Darwin may also use a SIGBUS (seen with compressed oops).

       // Catching SIGBUS here prevents the implicit SIGBUS NULL check below from

       // being called, so only do so if the implicit NULL check is not necessary.

       } else if (sig == SIGBUS && MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {

 #else

       } else if (sig == SIGBUS /* && info->si_code == BUS_OBJERR */) {

 #endif

         // BugId 4454115: A read from a MappedByteBuffer can fault

         // here if the underlying file has been truncated.

         // Do not crash the VM in such a case.

         CodeBlob* cb = CodeCache::find_blob_unsafe(pc);

         nmethod* nm = cb->is_nmethod() ? (nmethod*)cb : NULL;

         if (nm != NULL && nm->has_unsafe_access()) {

           stub = StubRoutines::handler_for_unsafe_access();

         }

       }

       else

 #ifdef AMD64

       if (sig == SIGFPE  &&

           (info->si_code == FPE_INTDIV || info->si_code == FPE_FLTDIV)) {

         stub =

           SharedRuntime::

           continuation_for_implicit_exception(thread,

                                               pc,

                                               SharedRuntime::

                                               IMPLICIT_DIVIDE_BY_ZERO);

 #ifdef __APPLE__

       } else if (sig == SIGFPE && info->si_code == FPE_NOOP) {

         int op = pc[0];

         // Skip REX

         if ((pc[0] & 0xf0) == 0x40) {

           op = pc[1];

         } else {

           op = pc[0];

         }

         // Check for IDIV

         if (op == 0xF7) {

           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime:: IMPLICIT_DIVIDE_BY_ZERO);

         } else {

           // TODO: handle more cases if we are using other x86 instructions

           //   that can generate SIGFPE signal.

           tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);

           fatal("please update this code.");

         }

 #endif /* __APPLE__ */

 #else

       if (sig == SIGFPE /* && info->si_code == FPE_INTDIV */) {

         // HACK: si_code does not work on bsd 2.2.12-20!!!

         int op = pc[0];

         if (op == 0xDB) {

           // FIST

           // TODO: The encoding of D2I in i486.ad can cause an exception

           // prior to the fist instruction if there was an invalid operation

           // pending. We want to dismiss that exception. From the win_32

           // side it also seems that if it really was the fist causing

           // the exception that we do the d2i by hand with different

           // rounding. Seems kind of weird.

           // NOTE: that we take the exception at the NEXT floating point instruction.

           assert(pc[0] == 0xDB, "not a FIST opcode");

           assert(pc[1] == 0x14, "not a FIST opcode");

           assert(pc[2] == 0x24, "not a FIST opcode");

           return true;

         } else if (op == 0xF7) {

           // IDIV

           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);

         } else {

           // TODO: handle more cases if we are using other x86 instructions

           //   that can generate SIGFPE signal on bsd.

           tty->print_cr("unknown opcode 0x%X with SIGFPE.", op);

           fatal("please update this code.");

         }

 #endif // AMD64

       } else if ((sig == SIGSEGV || sig == SIGBUS) &&

                !MacroAssembler::needs_explicit_null_check((intptr_t)info->si_addr)) {

           // Determination of interpreter/vtable stub/compiled code null exception

           stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL);

       }

     } else if (thread->thread_state() == _thread_in_vm &&

                sig == SIGBUS && /* info->si_code == BUS_OBJERR && */

                thread->doing_unsafe_access()) {

         stub = StubRoutines::handler_for_unsafe_access();

     }

     // jni_fast_Get<Primitive>Field can trap at certain pc's if a GC kicks in

     // and the heap gets shrunk before the field access.

     if ((sig == SIGSEGV) || (sig == SIGBUS)) {

       address addr = JNI_FastGetField::find_slowcase_pc(pc);

       if (addr != (address)-1) {

         stub = addr;

       }

     }

     // Check to see if we caught the safepoint code in the

     // process of write protecting the memory serialization page.

     // It write enables the page immediately after protecting it

     // so we can just return to retry the write.

     if ((sig == SIGSEGV || sig == SIGBUS) &&

         os::is_memory_serialize_page(thread, (address) info->si_addr)) {

       // Block current thread until the memory serialize page permission restored.

       os::block_on_serialize_page_trap();

       return true;

     }

   }

 #ifndef AMD64

   // Execution protection violation

   //

   // This should be kept as the last step in the triage.  We don't

   // have a dedicated trap number for a no-execute fault, so be

   // conservative and allow other handlers the first shot.

   //

   // Note: We don't test that info->si_code == SEGV_ACCERR here.

   // this si_code is so generic that it is almost meaningless; and

   // the si_code for this condition may change in the future.

   // Furthermore, a false-positive should be harmless.

   if (UnguardOnExecutionViolation > 0 &&

       (sig == SIGSEGV || sig == SIGBUS) &&

       uc->context_trapno == trap_page_fault) {

     int page_size = os::vm_page_size();

     address addr = (address) info->si_addr;

     address pc = os::Bsd::ucontext_get_pc(uc);

     // Make sure the pc and the faulting address are sane.

     //

     // If an instruction spans a page boundary, and the page containing

     // the beginning of the instruction is executable but the following

     // page is not, the pc and the faulting address might be slightly

     // different - we still want to unguard the 2nd page in this case.

     //

     // 15 bytes seems to be a (very) safe value for max instruction size.

     bool pc_is_near_addr =

       (pointer_delta((void*) addr, (void*) pc, sizeof(char)) < 15);

     bool instr_spans_page_boundary =

       (align_size_down((intptr_t) pc ^ (intptr_t) addr,

                        (intptr_t) page_size) > 0);

     if (pc == addr || (pc_is_near_addr && instr_spans_page_boundary)) {

       static volatile address last_addr =

         (address) os::non_memory_address_word();

       // In conservative mode, don't unguard unless the address is in the VM

       if (addr != last_addr &&

           (UnguardOnExecutionViolation > 1 || os::address_is_in_vm(addr))) {

         // Set memory to RWX and retry

         address page_start =

           (address) align_size_down((intptr_t) addr, (intptr_t) page_size);

         bool res = os::protect_memory((char*) page_start, page_size,

                                       os::MEM_PROT_RWX);

         if (PrintMiscellaneous && Verbose) {

           char buf[256];

           jio_snprintf(buf, sizeof(buf), "Execution protection violation "

                        "at " INTPTR_FORMAT

                        ", unguarding " INTPTR_FORMAT ": %s, errno=%d", addr,

                        page_start, (res ? "success" : "failed"), errno);

           tty->print_raw_cr(buf);

         }

         stub = pc;

         // Set last_addr so if we fault again at the same address, we don't end

         // up in an endless loop.

         //

         // There are two potential complications here.  Two threads trapping at

         // the same address at the same time could cause one of the threads to

         // think it already unguarded, and abort the VM.  Likely very rare.

         //

         // The other race involves two threads alternately trapping at

         // different addresses and failing to unguard the page, resulting in

         // an endless loop.  This condition is probably even more unlikely than

         // the first.

         //

         // Although both cases could be avoided by using locks or thread local

         // last_addr, these solutions are unnecessary complication: this

         // handler is a best-effort safety net, not a complete solution.  It is

         // disabled by default and should only be used as a workaround in case

         // we missed any no-execute-unsafe VM code.

         last_addr = addr;

       }

     }

   }

 #endif // !AMD64

   if (stub != NULL) {

     // save all thread context in case we need to restore it

     if (thread != NULL) thread->set_saved_exception_pc(pc);

     uc->context_pc = (intptr_t)stub;

     return true;

   }

   // signal-chaining

   if (os::Bsd::chained_handler(sig, info, ucVoid)) {

      return true;

   }

   if (!abort_if_unrecognized) {

     // caller wants another chance, so give it to him

     return false;

   }

   if (pc == NULL && uc != NULL) {

     pc = os::Bsd::ucontext_get_pc(uc);

   }

   // unmask current signal

   sigset_t newset;

   sigemptyset(&newset);

   sigaddset(&newset, sig);

   sigprocmask(SIG_UNBLOCK, &newset, NULL);

   VMError err(t, sig, pc, info, ucVoid);

   err.report_and_die();

   ShouldNotReachHere();

 }

 // From solaris_i486.s ported to bsd_i486.s

 extern "C" void fixcw();

 void os::Bsd::init_thread_fpu_state(void) {

 #ifndef AMD64

   // Set fpu to 53 bit precision. This happens too early to use a stub.

   fixcw();

 #endif // !AMD64

 }

 // Check that the bsd kernel version is 2.4 or higher since earlier

 // versions do not support SSE without patches.

 bool os::supports_sse() {

   return true;

 }

 bool os::is_allocatable(size_t bytes) {

 #ifdef AMD64

   // unused on amd64?

   return true;

 #else

   if (bytes < 2 * G) {

     return true;

   }

   char* addr = reserve_memory(bytes, NULL);

   if (addr != NULL) {

     release_memory(addr, bytes);

   }

   return addr != NULL;

 #endif // AMD64

 }

 ////////////////////////////////////////////////////////////////////////////////

 // thread stack

 #ifdef AMD64

 size_t os::Bsd::min_stack_allowed  = 64 * K;

 // amd64: pthread on amd64 is always in floating stack mode

 bool os::Bsd::supports_variable_stack_size() {  return true; }

 #else

 size_t os::Bsd::min_stack_allowed  =  (48 DEBUG_ONLY(+4))*K;

 #ifdef __GNUC__

 #define GET_GS() ({int gs; __asm__ volatile("movw %%gs, %w0":"=q"(gs)); gs&0xffff;})

 #endif

 bool os::Bsd::supports_variable_stack_size() { return true; }

 #endif // AMD64

 // return default stack size for thr_type

 size_t os::Bsd::default_stack_size(os::ThreadType thr_type) {

   // default stack size (compiler thread needs larger stack)

 #ifdef AMD64

   size_t s = (thr_type == os::compiler_thread ? 4 * M : 1 * M);

 #else

   size_t s = (thr_type == os::compiler_thread ? 2 * M : 512 * K);

 #endif // AMD64

   return s;

 }

 size_t os::Bsd::default_guard_size(os::ThreadType thr_type) {

   // Creating guard page is very expensive. Java thread has HotSpot

   // guard page, only enable glibc guard page for non-Java threads.

   return (thr_type == java_thread ? 0 : page_size());

 }

 // Java thread:

 //

 //   Low memory addresses

 //    +------------------------+

 //    |                        |\  JavaThread created by VM does not have glibc

 //    |    glibc guard page    | - guard, attached Java thread usually has

 //    |                        |/  1 page glibc guard.

 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()

 //    |                        |\

 //    |  HotSpot Guard Pages   | - red and yellow pages

 //    |                        |/

 //    +------------------------+ JavaThread::stack_yellow_zone_base()

 //    |                        |\

 //    |      Normal Stack      | -

 //    |                        |/

 // P2 +------------------------+ Thread::stack_base()

 //

 // Non-Java thread:

 //

 //   Low memory addresses

 //    +------------------------+

 //    |                        |\

 //    |  glibc guard page      | - usually 1 page

 //    |                        |/

 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()

 //    |                        |\

 //    |      Normal Stack      | -

 //    |                        |/

 // P2 +------------------------+ Thread::stack_base()

 //

 // ** P1 (aka bottom) and size ( P2 = P1 - size) are the address and stack size returned from

 //    pthread_attr_getstack()

 static void current_stack_region(address * bottom, size_t * size) {

 #ifdef __APPLE__

   pthread_t self = pthread_self();

   void *stacktop = pthread_get_stackaddr_np(self);

   *size = pthread_get_stacksize_np(self);

   *bottom = (address) stacktop - *size;

 #elif defined(__OpenBSD__)

   stack_t ss;

   int rslt = pthread_stackseg_np(pthread_self(), &ss);

   if (rslt != 0)

     fatal(err_msg("pthread_stackseg_np failed with err = %d", rslt));

   *bottom = (address)((char *)ss.ss_sp - ss.ss_size);

   *size   = ss.ss_size;

 #else

   pthread_attr_t attr;

   int rslt = pthread_attr_init(&attr);

   // JVM needs to know exact stack location, abort if it fails

   if (rslt != 0)

     fatal(err_msg("pthread_attr_init failed with err = %d", rslt));

   rslt = pthread_attr_get_np(pthread_self(), &attr);

   if (rslt != 0)

     fatal(err_msg("pthread_attr_get_np failed with err = %d", rslt));

   if (pthread_attr_getstackaddr(&attr, (void **)bottom) != 0 ||

     pthread_attr_getstacksize(&attr, size) != 0) {

     fatal("Can not locate current stack attributes!");

   }

   pthread_attr_destroy(&attr);

 #endif

   assert(os::current_stack_pointer() >= *bottom &&

          os::current_stack_pointer() < *bottom + *size, "just checking");

 }

 address os::current_stack_base() {

   address bottom;

   size_t size;

   current_stack_region(&bottom, &size);

   return (bottom + size);

 }

 size_t os::current_stack_size() {

   // stack size includes normal stack and HotSpot guard pages

   address bottom;

   size_t size;

   current_stack_region(&bottom, &size);

   return size;

 }

 /////////////////////////////////////////////////////////////////////////////

 // helper functions for fatal error handler

 void os::print_context(outputStream *st, void *context) {

   if (context == NULL) return;

   ucontext_t *uc = (ucontext_t*)context;

   st->print_cr("Registers:");

 #ifdef AMD64

   st->print(  "RAX=" INTPTR_FORMAT, uc->context_rax);

   st->print(", RBX=" INTPTR_FORMAT, uc->context_rbx);

   st->print(", RCX=" INTPTR_FORMAT, uc->context_rcx);

   st->print(", RDX=" INTPTR_FORMAT, uc->context_rdx);

   st->cr();

   st->print(  "RSP=" INTPTR_FORMAT, uc->context_rsp);

   st->print(", RBP=" INTPTR_FORMAT, uc->context_rbp);

   st->print(", RSI=" INTPTR_FORMAT, uc->context_rsi);

   st->print(", RDI=" INTPTR_FORMAT, uc->context_rdi);

   st->cr();

   st->print(  "R8 =" INTPTR_FORMAT, uc->context_r8);

   st->print(", R9 =" INTPTR_FORMAT, uc->context_r9);

   st->print(", R10=" INTPTR_FORMAT, uc->context_r10);

   st->print(", R11=" INTPTR_FORMAT, uc->context_r11);

   st->cr();

   st->print(  "R12=" INTPTR_FORMAT, uc->context_r12);

   st->print(", R13=" INTPTR_FORMAT, uc->context_r13);

   st->print(", R14=" INTPTR_FORMAT, uc->context_r14);

   st->print(", R15=" INTPTR_FORMAT, uc->context_r15);

   st->cr();

   st->print(  "RIP=" INTPTR_FORMAT, uc->context_rip);

   st->print(", EFLAGS=" INTPTR_FORMAT, uc->context_flags);

   st->print(", ERR=" INTPTR_FORMAT, uc->context_err);

   st->cr();

   st->print("  TRAPNO=" INTPTR_FORMAT, uc->context_trapno);

 #else

   st->print(  "EAX=" INTPTR_FORMAT, uc->context_eax);

   st->print(", EBX=" INTPTR_FORMAT, uc->context_ebx);

   st->print(", ECX=" INTPTR_FORMAT, uc->context_ecx);

   st->print(", EDX=" INTPTR_FORMAT, uc->context_edx);

   st->cr();

   st->print(  "ESP=" INTPTR_FORMAT, uc->context_esp);

   st->print(", EBP=" INTPTR_FORMAT, uc->context_ebp);

   st->print(", ESI=" INTPTR_FORMAT, uc->context_esi);

   st->print(", EDI=" INTPTR_FORMAT, uc->context_edi);

   st->cr();

   st->print(  "EIP=" INTPTR_FORMAT, uc->context_eip);

   st->print(", EFLAGS=" INTPTR_FORMAT, uc->context_eflags);

 #endif // AMD64

   st->cr();

   st->cr();

   intptr_t *sp = (intptr_t *)os::Bsd::ucontext_get_sp(uc);

   st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);

   print_hex_dump(st, (address)sp, (address)(sp + 8*sizeof(intptr_t)), sizeof(intptr_t));

   st->cr();

   // Note: it may be unsafe to inspect memory near pc. For example, pc may

   // point to garbage if entry point in an nmethod is corrupted. Leave

   // this at the end, and hope for the best.

   address pc = os::Bsd::ucontext_get_pc(uc);

   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);

   print_hex_dump(st, pc - 32, pc + 32, sizeof(char));

 }

 void os::print_register_info(outputStream *st, void *context) {

   if (context == NULL) return;

   ucontext_t *uc = (ucontext_t*)context;

   st->print_cr("Register to memory mapping:");

   st->cr();

   // this is horrendously verbose but the layout of the registers in the

   // context does not match how we defined our abstract Register set, so

   // we can't just iterate through the gregs area

   // this is only for the "general purpose" registers

 #ifdef AMD64

   st->print("RAX="); print_location(st, uc->context_rax);

   st->print("RBX="); print_location(st, uc->context_rbx);

   st->print("RCX="); print_location(st, uc->context_rcx);

   st->print("RDX="); print_location(st, uc->context_rdx);

   st->print("RSP="); print_location(st, uc->context_rsp);

   st->print("RBP="); print_location(st, uc->context_rbp);

   st->print("RSI="); print_location(st, uc->context_rsi);

   st->print("RDI="); print_location(st, uc->context_rdi);

   st->print("R8 ="); print_location(st, uc->context_r8);

   st->print("R9 ="); print_location(st, uc->context_r9);

   st->print("R10="); print_location(st, uc->context_r10);

   st->print("R11="); print_location(st, uc->context_r11);

   st->print("R12="); print_location(st, uc->context_r12);

   st->print("R13="); print_location(st, uc->context_r13);

   st->print("R14="); print_location(st, uc->context_r14);

   st->print("R15="); print_location(st, uc->context_r15);

 #else

   st->print("EAX="); print_location(st, uc->context_eax);

   st->print("EBX="); print_location(st, uc->context_ebx);

   st->print("ECX="); print_location(st, uc->context_ecx);

   st->print("EDX="); print_location(st, uc->context_edx);

   st->print("ESP="); print_location(st, uc->context_esp);

   st->print("EBP="); print_location(st, uc->context_ebp);

   st->print("ESI="); print_location(st, uc->context_esi);

   st->print("EDI="); print_location(st, uc->context_edi);

 #endif // AMD64

   st->cr();

 }

 void os::setup_fpu() {

 #ifndef AMD64

   address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();

   __asm__ volatile (  "fldcw (%0)" :

                       : "r" (fpu_cntrl) : "memory");

 #endif // !AMD64

 }

 #ifndef PRODUCT

 void os::verify_stack_alignment() {

 }

 #endif