--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/os_cpu/solaris_x86/vm/os_solaris_x86.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,878 @@
+/*
+ * Copyright 1999-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// do not include  precompiled  header file
+# include "incls/_os_solaris_x86.cpp.incl"
+
+// put OS-includes here
+# include <sys/types.h>
+# include <sys/mman.h>
+# include <pthread.h>
+# include <signal.h>
+# include <setjmp.h>
+# include <errno.h>
+# include <dlfcn.h>
+# include <stdio.h>
+# include <unistd.h>
+# include <sys/resource.h>
+# include <thread.h>
+# include <sys/stat.h>
+# include <sys/time.h>
+# include <sys/filio.h>
+# include <sys/utsname.h>
+# include <sys/systeminfo.h>
+# include <sys/socket.h>
+# include <sys/trap.h>
+# include <sys/lwp.h>
+# include <pwd.h>
+# include <poll.h>
+# include <sys/lwp.h>
+# include <procfs.h>     //  see comment in <sys/procfs.h>
+
+#ifndef AMD64
+// QQQ seems useless at this point
+# define _STRUCTURED_PROC 1  //  this gets us the new structured proc interfaces of 5.6 & later
+#endif // AMD64
+# include <sys/procfs.h>     //  see comment in <sys/procfs.h>
+
+
+#define MAX_PATH (2 * K)
+
+// Minimum stack size for the VM.  It's easier to document a constant value
+// but it's different for x86 and sparc because the page sizes are different.
+#ifdef AMD64
+size_t os::Solaris::min_stack_allowed = 224*K;
+#define REG_SP REG_RSP
+#define REG_PC REG_RIP
+#define REG_FP REG_RBP
+#else
+size_t os::Solaris::min_stack_allowed = 64*K;
+#define REG_SP UESP
+#define REG_PC EIP
+#define REG_FP EBP
+// 4900493 counter to prevent runaway LDTR refresh attempt
+
+static volatile int ldtr_refresh = 0;
+// the libthread instruction that faults because of the stale LDTR
+
+static const unsigned char movlfs[] = { 0x8e, 0xe0    // movl %eax,%fs
+                       };
+#endif // AMD64
+
+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;
+}
+
+//
+// Validate a ucontext retrieved from walking a uc_link of a ucontext.
+// There are issues with libthread giving out uc_links for different threads
+// on the same uc_link chain and bad or circular links.
+//
+bool os::Solaris::valid_ucontext(Thread* thread, ucontext_t* valid, ucontext_t* suspect) {
+  if (valid >= suspect ||
+      valid->uc_stack.ss_flags != suspect->uc_stack.ss_flags ||
+      valid->uc_stack.ss_sp    != suspect->uc_stack.ss_sp    ||
+      valid->uc_stack.ss_size  != suspect->uc_stack.ss_size) {
+    DEBUG_ONLY(tty->print_cr("valid_ucontext: failed test 1");)
+    return false;
+  }
+
+  if (thread->is_Java_thread()) {
+    if (!valid_stack_address(thread, (address)suspect)) {
+      DEBUG_ONLY(tty->print_cr("valid_ucontext: uc_link not in thread stack");)
+      return false;
+    }
+    if (!valid_stack_address(thread,  (address) suspect->uc_mcontext.gregs[REG_SP])) {
+      DEBUG_ONLY(tty->print_cr("valid_ucontext: stackpointer not in thread stack");)
+      return false;
+    }
+  }
+  return true;
+}
+
+// We will only follow one level of uc_link since there are libthread
+// issues with ucontext linking and it is better to be safe and just
+// let caller retry later.
+ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread,
+  ucontext_t *uc) {
+
+  ucontext_t *retuc = NULL;
+
+  if (uc != NULL) {
+    if (uc->uc_link == NULL) {
+      // cannot validate without uc_link so accept current ucontext
+      retuc = uc;
+    } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
+      // first ucontext is valid so try the next one
+      uc = uc->uc_link;
+      if (uc->uc_link == NULL) {
+        // cannot validate without uc_link so accept current ucontext
+        retuc = uc;
+      } else if (os::Solaris::valid_ucontext(thread, uc, uc->uc_link)) {
+        // the ucontext one level down is also valid so return it
+        retuc = uc;
+      }
+    }
+  }
+  return retuc;
+}
+
+// Assumes ucontext is valid
+ExtendedPC os::Solaris::ucontext_get_ExtendedPC(ucontext_t *uc) {
+  return ExtendedPC((address)uc->uc_mcontext.gregs[REG_PC]);
+}
+
+// Assumes ucontext is valid
+intptr_t* os::Solaris::ucontext_get_sp(ucontext_t *uc) {
+  return (intptr_t*)uc->uc_mcontext.gregs[REG_SP];
+}
+
+// Assumes ucontext is valid
+intptr_t* os::Solaris::ucontext_get_fp(ucontext_t *uc) {
+  return (intptr_t*)uc->uc_mcontext.gregs[REG_FP];
+}
+
+// For Forte Analyzer AsyncGetCallTrace profiling support - thread
+// is currently interrupted by SIGPROF.
+//
+// The difference between this and os::fetch_frame_from_context() is that
+// here we try to skip nested signal frames.
+ExtendedPC os::Solaris::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");
+
+  ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc);
+  return os::fetch_frame_from_context(luc, 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 = os::Solaris::ucontext_get_ExtendedPC(uc);
+    if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc);
+    if (ret_fp) *ret_fp = os::Solaris::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());
+}
+
+frame os::get_sender_for_C_frame(frame* fr) {
+  return frame(fr->sender_sp(), fr->link(), fr->sender_pc());
+}
+
+extern "C" intptr_t *_get_previous_fp();  // in .il file.
+
+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(NULL, NULL, NULL);
+  } else {
+    return os::get_sender_for_C_frame(&myframe);
+  }
+}
+
+// This is a simple callback that just fetches a PC for an interrupted thread.
+// The thread need not be suspended and the fetched PC is just a hint.
+// This one is currently used for profiling the VMThread ONLY!
+
+// Must be synchronous
+void GetThreadPC_Callback::execute(OSThread::InterruptArguments *args) {
+  Thread*     thread = args->thread();
+  ucontext_t* uc     = args->ucontext();
+  intptr_t* sp;
+
+  assert(ProfileVM && thread->is_VM_thread(), "just checking");
+
+  ExtendedPC new_addr((address)uc->uc_mcontext.gregs[REG_PC]);
+  _addr = new_addr;
+}
+
+static int threadgetstate(thread_t tid, int *flags, lwpid_t *lwp, stack_t *ss, gregset_t rs, lwpstatus_t *lwpstatus) {
+  char lwpstatusfile[PROCFILE_LENGTH];
+  int lwpfd, err;
+
+  if (err = os::Solaris::thr_getstate(tid, flags, lwp, ss, rs))
+    return (err);
+  if (*flags == TRS_LWPID) {
+    sprintf(lwpstatusfile, "/proc/%d/lwp/%d/lwpstatus", getpid(),
+            *lwp);
+    if ((lwpfd = open(lwpstatusfile, O_RDONLY)) < 0) {
+      perror("thr_mutator_status: open lwpstatus");
+      return (EINVAL);
+    }
+    if (pread(lwpfd, lwpstatus, sizeof (lwpstatus_t), (off_t)0) !=
+        sizeof (lwpstatus_t)) {
+      perror("thr_mutator_status: read lwpstatus");
+      (void) close(lwpfd);
+      return (EINVAL);
+    }
+    (void) close(lwpfd);
+  }
+  return (0);
+}
+
+#ifndef AMD64
+
+// Detecting SSE support by OS
+// From solaris_i486.s
+extern "C" bool sse_check();
+extern "C" bool sse_unavailable();
+
+enum { SSE_UNKNOWN, SSE_NOT_SUPPORTED, SSE_SUPPORTED};
+static int sse_status = SSE_UNKNOWN;
+
+
+static void  check_for_sse_support() {
+  if (!VM_Version::supports_sse()) {
+    sse_status = SSE_NOT_SUPPORTED;
+    return;
+  }
+  // looking for _sse_hw in libc.so, if it does not exist or
+  // the value (int) is 0, OS has no support for SSE
+  int *sse_hwp;
+  void *h;
+
+  if ((h=dlopen("/usr/lib/libc.so", RTLD_LAZY)) == NULL) {
+    //open failed, presume no support for SSE
+    sse_status = SSE_NOT_SUPPORTED;
+    return;
+  }
+  if ((sse_hwp = (int *)dlsym(h, "_sse_hw")) == NULL) {
+    sse_status = SSE_NOT_SUPPORTED;
+  } else if (*sse_hwp == 0) {
+    sse_status = SSE_NOT_SUPPORTED;
+  }
+  dlclose(h);
+
+  if (sse_status == SSE_UNKNOWN) {
+    bool (*try_sse)() = (bool (*)())sse_check;
+    sse_status = (*try_sse)() ? SSE_SUPPORTED : SSE_NOT_SUPPORTED;
+  }
+
+}
+
+bool os::supports_sse() {
+  if (sse_status == SSE_UNKNOWN)
+    check_for_sse_support();
+  return sse_status == SSE_SUPPORTED;
+}
+
+#endif // AMD64
+
+bool os::is_allocatable(size_t bytes) {
+#ifdef 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
+
+}
+
+extern "C" int JVM_handle_solaris_signal(int signo, siginfo_t* siginfo, void* ucontext, int abort_if_unrecognized);
+
+extern "C" void Fetch32PFI () ;
+extern "C" void Fetch32Resume () ;
+#ifdef AMD64
+extern "C" void FetchNPFI () ;
+extern "C" void FetchNResume () ;
+#endif // AMD64
+
+int JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid, int abort_if_unrecognized) {
+  ucontext_t* uc = (ucontext_t*) ucVoid;
+
+#ifndef AMD64
+  if (sig == SIGILL && info->si_addr == (caddr_t)sse_check) {
+    // the SSE instruction faulted. supports_sse() need return false.
+    uc->uc_mcontext.gregs[EIP] = (greg_t)sse_unavailable;
+    return true;
+  }
+#endif // !AMD64
+
+  Thread* t = ThreadLocalStorage::get_thread_slow();  // slow & steady
+
+  SignalHandlerMark shm(t);
+
+  if(sig == SIGPIPE || sig == SIGXFSZ) {
+    if (os::Solaris::chained_handler(sig, info, ucVoid)) {
+      return true;
+    } else {
+      if (PrintMiscellaneous && (WizardMode || Verbose)) {
+        char buf[64];
+        warning("Ignoring %s - see 4229104 or 6499219",
+                os::exception_name(sig, buf, sizeof(buf)));
+
+      }
+      return true;
+    }
+  }
+
+  JavaThread* thread = NULL;
+  VMThread* vmthread = NULL;
+
+  if (os::Solaris::signal_handlers_are_installed) {
+    if (t != NULL ){
+      if(t->is_Java_thread()) {
+        thread = (JavaThread*)t;
+      }
+      else if(t->is_VM_thread()){
+        vmthread = (VMThread *)t;
+      }
+    }
+  }
+
+  guarantee(sig != os::Solaris::SIGinterrupt(), "Can not chain VM interrupt signal, try -XX:+UseAltSigs");
+
+  if (sig == os::Solaris::SIGasync()) {
+    if(thread){
+      OSThread::InterruptArguments args(thread, uc);
+      thread->osthread()->do_interrupt_callbacks_at_interrupt(&args);
+      return true;
+    }
+    else if(vmthread){
+      OSThread::InterruptArguments args(vmthread, uc);
+      vmthread->osthread()->do_interrupt_callbacks_at_interrupt(&args);
+      return true;
+    } else if (os::Solaris::chained_handler(sig, info, ucVoid)) {
+      return true;
+    } else {
+      // If os::Solaris::SIGasync not chained, and this is a non-vm and
+      // non-java thread
+      return true;
+    }
+  }
+
+  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) {
+    // factor me: getPCfromContext
+    pc = (address) uc->uc_mcontext.gregs[REG_PC];
+
+    // SafeFetch32() support
+    if (pc == (address) Fetch32PFI) {
+      uc->uc_mcontext.gregs[REG_PC] = intptr_t(Fetch32Resume) ;
+      return true ;
+    }
+#ifdef AMD64
+    if (pc == (address) FetchNPFI) {
+       uc->uc_mcontext.gregs [REG_PC] = intptr_t(FetchNResume) ;
+       return true ;
+    }
+#endif // AMD64
+
+    // Handle ALL stack overflow variations here
+    if (sig == SIGSEGV && info->si_code == SEGV_ACCERR) {
+      address addr = (address) info->si_addr;
+      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 true;
+        }
+      } 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.");
+      }
+    }
+
+    if (thread->thread_state() == _thread_in_vm) {
+      if (sig == SIGBUS && info->si_code == BUS_OBJERR && thread->doing_unsafe_access()) {
+        stub = StubRoutines::handler_for_unsafe_access();
+      }
+    }
+
+    if (thread->thread_state() == _thread_in_Java) {
+      // Support Safepoint Polling
+      if ( sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
+        stub = SharedRuntime::get_poll_stub(pc);
+      }
+      else if (sig == SIGBUS && info->si_code == BUS_OBJERR) {
+        // 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
+      if (sig == SIGFPE && info->si_code == FPE_INTDIV) {
+        // integer divide by zero
+        stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
+      }
+#ifndef AMD64
+      else if (sig == SIGFPE && info->si_code == FPE_FLTDIV) {
+        // floating-point divide by zero
+        stub = SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_DIVIDE_BY_ZERO);
+      }
+      else if (sig == SIGFPE && info->si_code == FPE_FLTINV) {
+        // 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. QQQ TODO
+        // Note that we take the exception at the NEXT floating point instruction.
+        if (pc[0] == 0xDB) {
+            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 {
+            assert(pc[-3] == 0xDB, "not an flt invalid opcode");
+            assert(pc[-2] == 0x14, "not an flt invalid opcode");
+            assert(pc[-1] == 0x24, "not an flt invalid opcode");
+        }
+      }
+      else if (sig == SIGFPE ) {
+        tty->print_cr("caught SIGFPE, info 0x%x.", info->si_code);
+      }
+#endif // !AMD64
+
+        // QQQ It doesn't seem that we need to do this on x86 because we should be able
+        // to return properly from the handler without this extra stuff on the back side.
+
+      else if (sig == SIGSEGV && info->si_code > 0 && !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);
+      }
+    }
+
+    // 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) &&
+        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;
+    }
+  }
+
+  // Execution protection violation
+  //
+  // Preventative code for future versions of Solaris which may
+  // enable execution protection when running the 32-bit VM on AMD64.
+  //
+  // 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->uc_mcontext.gregs[TRAPNO] == T_PGFLT) {  // page fault
+    int page_size = os::vm_page_size();
+    address addr = (address) info->si_addr;
+    address pc = (address) uc->uc_mcontext.gregs[REG_PC];
+    // 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))) {
+
+        // Unguard and retry
+        address page_start =
+          (address) align_size_down((intptr_t) addr, (intptr_t) page_size);
+        bool res = os::unguard_memory((char*) page_start, page_size);
+
+        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;
+      }
+    }
+  }
+
+  if (stub != NULL) {
+    // save all thread context in case we need to restore it
+
+    if (thread != NULL) thread->set_saved_exception_pc(pc);
+    // 12/02/99: On Sparc it appears that the full context is also saved
+    // but as yet, no one looks at or restores that saved context
+    // factor me: setPC
+    uc->uc_mcontext.gregs[REG_PC] = (greg_t)stub;
+    return true;
+  }
+
+  // signal-chaining
+  if (os::Solaris::chained_handler(sig, info, ucVoid)) {
+    return true;
+  }
+
+#ifndef AMD64
+  // Workaround (bug 4900493) for Solaris kernel bug 4966651.
+  // Handle an undefined selector caused by an attempt to assign
+  // fs in libthread getipriptr(). With the current libthread design every 512
+  // thread creations the LDT for a private thread data structure is extended
+  // and thre is a hazard that and another thread attempting a thread creation
+  // will use a stale LDTR that doesn't reflect the structure's growth,
+  // causing a GP fault.
+  // Enforce the probable limit of passes through here to guard against an
+  // infinite loop if some other move to fs caused the GP fault. Note that
+  // this loop counter is ultimately a heuristic as it is possible for
+  // more than one thread to generate this fault at a time in an MP system.
+  // In the case of the loop count being exceeded or if the poll fails
+  // just fall through to a fatal error.
+  // If there is some other source of T_GPFLT traps and the text at EIP is
+  // unreadable this code will loop infinitely until the stack is exausted.
+  // The key to diagnosis in this case is to look for the bottom signal handler
+  // frame.
+
+  if(! IgnoreLibthreadGPFault) {
+    if (sig == SIGSEGV && uc->uc_mcontext.gregs[TRAPNO] == T_GPFLT) {
+      const unsigned char *p =
+                        (unsigned const char *) uc->uc_mcontext.gregs[EIP];
+
+      // Expected instruction?
+
+      if(p[0] == movlfs[0] && p[1] == movlfs[1]) {
+
+        Atomic::inc(&ldtr_refresh);
+
+        // Infinite loop?
+
+        if(ldtr_refresh < ((2 << 16) / PAGESIZE)) {
+
+          // No, force scheduling to get a fresh view of the LDTR
+
+          if(poll(NULL, 0, 10) == 0) {
+
+            // Retry the move
+
+            return false;
+          }
+        }
+      }
+    }
+  }
+#endif // !AMD64
+
+  if (!abort_if_unrecognized) {
+    // caller wants another chance, so give it to him
+    return false;
+  }
+
+  if (!os::Solaris::libjsig_is_loaded) {
+    struct sigaction oldAct;
+    sigaction(sig, (struct sigaction *)0, &oldAct);
+    if (oldAct.sa_sigaction != signalHandler) {
+      void* sighand = oldAct.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
+                                          : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
+      warning("Unexpected Signal %d occured under user-defined signal handler %#lx", sig, (long)sighand);
+    }
+  }
+
+  if (pc == NULL && uc != NULL) {
+    pc = (address) uc->uc_mcontext.gregs[REG_PC];
+  }
+
+  // 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();
+}
+
+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->uc_mcontext.gregs[REG_RAX]);
+  st->print(", RBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBX]);
+  st->print(", RCX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RCX]);
+  st->print(", RDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDX]);
+  st->cr();
+  st->print(  "RSP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSP]);
+  st->print(", RBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RBP]);
+  st->print(", RSI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RSI]);
+  st->print(", RDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RDI]);
+  st->cr();
+  st->print(", R8=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R8]);
+  st->print(", R9=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R9]);
+  st->print(", R10=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R10]);
+  st->print(", R11=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R11]);
+  st->print(", R12=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R12]);
+  st->print(", R13=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R13]);
+  st->print(", R14=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R14]);
+  st->print(", R15=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_R15]);
+  st->cr();
+  st->print(  "RIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RIP]);
+  st->print(", RFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[REG_RFL]);
+#else
+  st->print(  "EAX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EAX]);
+  st->print(", EBX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBX]);
+  st->print(", ECX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ECX]);
+  st->print(", EDX=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDX]);
+  st->cr();
+  st->print(  "ESP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[UESP]);
+  st->print(", EBP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EBP]);
+  st->print(", ESI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[ESI]);
+  st->print(", EDI=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EDI]);
+  st->cr();
+  st->print(  "EIP=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EIP]);
+  st->print(", EFLAGS=" INTPTR_FORMAT, uc->uc_mcontext.gregs[EFL]);
+#endif // AMD64
+  st->cr();
+  st->cr();
+
+  intptr_t *sp = (intptr_t *)os::Solaris::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.
+  ExtendedPC epc = os::Solaris::ucontext_get_ExtendedPC(uc);
+  address pc = epc.pc();
+  st->print_cr("Instructions: (pc=" PTR_FORMAT ")", pc);
+  print_hex_dump(st, pc - 16, pc + 16, sizeof(char));
+}
+
+#ifdef AMD64
+void os::Solaris::init_thread_fpu_state(void) {
+  // Nothing to do
+}
+#else
+// From solaris_i486.s
+extern "C" void fixcw();
+
+void os::Solaris::init_thread_fpu_state(void) {
+  // Set fpu to 53 bit precision. This happens too early to use a stub.
+  fixcw();
+}
+
+// These routines are the initial value of atomic_xchg_entry(),
+// atomic_cmpxchg_entry(), atomic_inc_entry() and fence_entry()
+// until initialization is complete.
+// TODO - replace with .il implementation when compiler supports it.
+
+typedef jint  xchg_func_t        (jint,  volatile jint*);
+typedef jint  cmpxchg_func_t     (jint,  volatile jint*,  jint);
+typedef jlong cmpxchg_long_func_t(jlong, volatile jlong*, jlong);
+typedef jint  add_func_t         (jint,  volatile jint*);
+typedef void  fence_func_t       ();
+
+jint os::atomic_xchg_bootstrap(jint exchange_value, volatile jint* dest) {
+  // try to use the stub:
+  xchg_func_t* func = CAST_TO_FN_PTR(xchg_func_t*, StubRoutines::atomic_xchg_entry());
+
+  if (func != NULL) {
+    os::atomic_xchg_func = func;
+    return (*func)(exchange_value, dest);
+  }
+  assert(Threads::number_of_threads() == 0, "for bootstrap only");
+
+  jint old_value = *dest;
+  *dest = exchange_value;
+  return old_value;
+}
+
+jint os::atomic_cmpxchg_bootstrap(jint exchange_value, volatile jint* dest, jint compare_value) {
+  // try to use the stub:
+  cmpxchg_func_t* func = CAST_TO_FN_PTR(cmpxchg_func_t*, StubRoutines::atomic_cmpxchg_entry());
+
+  if (func != NULL) {
+    os::atomic_cmpxchg_func = func;
+    return (*func)(exchange_value, dest, compare_value);
+  }
+  assert(Threads::number_of_threads() == 0, "for bootstrap only");
+
+  jint old_value = *dest;
+  if (old_value == compare_value)
+    *dest = exchange_value;
+  return old_value;
+}
+
+jlong os::atomic_cmpxchg_long_bootstrap(jlong exchange_value, volatile jlong* dest, jlong compare_value) {
+  // try to use the stub:
+  cmpxchg_long_func_t* func = CAST_TO_FN_PTR(cmpxchg_long_func_t*, StubRoutines::atomic_cmpxchg_long_entry());
+
+  if (func != NULL) {
+    os::atomic_cmpxchg_long_func = func;
+    return (*func)(exchange_value, dest, compare_value);
+  }
+  assert(Threads::number_of_threads() == 0, "for bootstrap only");
+
+  jlong old_value = *dest;
+  if (old_value == compare_value)
+    *dest = exchange_value;
+  return old_value;
+}
+
+jint os::atomic_add_bootstrap(jint add_value, volatile jint* dest) {
+  // try to use the stub:
+  add_func_t* func = CAST_TO_FN_PTR(add_func_t*, StubRoutines::atomic_add_entry());
+
+  if (func != NULL) {
+    os::atomic_add_func = func;
+    return (*func)(add_value, dest);
+  }
+  assert(Threads::number_of_threads() == 0, "for bootstrap only");
+
+  return (*dest) += add_value;
+}
+
+void os::fence_bootstrap() {
+  // try to use the stub:
+  fence_func_t* func = CAST_TO_FN_PTR(fence_func_t*, StubRoutines::fence_entry());
+
+  if (func != NULL) {
+    os::fence_func = func;
+    (*func)();
+    return;
+  }
+  assert(Threads::number_of_threads() == 0, "for bootstrap only");
+
+  // don't have to do anything for a single thread
+}
+
+xchg_func_t*         os::atomic_xchg_func         = os::atomic_xchg_bootstrap;
+cmpxchg_func_t*      os::atomic_cmpxchg_func      = os::atomic_cmpxchg_bootstrap;
+cmpxchg_long_func_t* os::atomic_cmpxchg_long_func = os::atomic_cmpxchg_long_bootstrap;
+add_func_t*          os::atomic_add_func          = os::atomic_add_bootstrap;
+fence_func_t*        os::fence_func               = os::fence_bootstrap;
+
+extern "C" _solaris_raw_setup_fpu(address ptr);
+void os::setup_fpu() {
+  address fpu_cntrl = StubRoutines::addr_fpu_cntrl_wrd_std();
+  _solaris_raw_setup_fpu(fpu_cntrl);
+}
+#endif // AMD64