src/hotspot/os_cpu/solaris_sparc/os_solaris_sparc.cpp

/*
 * Copyright (c) 1999, 2017, 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 "jvm.h"
#include "asm/macroAssembler.hpp"
#include "macroAssembler_sparc.hpp"
#include "classfile/classLoader.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
#include "code/codeCache.hpp"
#include "code/icBuffer.hpp"
#include "code/vtableStubs.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/allocation.inline.hpp"
#include "nativeInst_sparc.hpp"
#include "os_share_solaris.hpp"
#include "prims/jniFastGetField.hpp"
#include "prims/jvm_misc.hpp"
#include "runtime/arguments.hpp"
#include "runtime/extendedPC.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/interfaceSupport.inline.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"

# include <signal.h>        // needed first to avoid name collision for "std" with SC 5.0

// put OS-includes here
# include <sys/types.h>
# include <sys/mman.h>
# include <pthread.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/lwp.h>
# include <poll.h>
# include <sys/lwp.h>

# define _STRUCTURED_PROC 1  //  this gets us the new structured proc interfaces of 5.6 & later
# include <sys/procfs.h>     //  see comment in <sys/procfs.h>

#define MAX_PATH (2 * K)

// Minimum usable stack sizes required to get to user code. Space for
// HotSpot guard pages is added later.
size_t os::Posix::_compiler_thread_min_stack_allowed = 104 * K;
size_t os::Posix::_java_thread_min_stack_allowed = 86 * K;
size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;

int os::Solaris::max_register_window_saves_before_flushing() {
  // We should detect this at run time. For now, filling
  // in with a constant.
  return 8;
}

static void handle_unflushed_register_windows(gwindows_t *win) {
  int restore_count = win->wbcnt;
  int i;

  for(i=0; i<restore_count; i++) {
    address sp = ((address)win->spbuf[i]) + STACK_BIAS;
    address reg_win = (address)&win->wbuf[i];
    memcpy(sp,reg_win,sizeof(struct rwindow));
  }
}

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).
  // On SPARC, 0 != %hi(any real address), because there is no
  // allocation in the first 1Kb of the virtual address space.
  return (char*) 0;
}

// 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, const ucontext_t* valid, const 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;
    }
    address _sp   = (address)((intptr_t)suspect->uc_mcontext.gregs[REG_SP] + STACK_BIAS);
    if (!valid_stack_address(thread, _sp) ||
        !frame::is_valid_stack_pointer(((JavaThread*)thread)->base_of_stack_pointer(), (intptr_t*)_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.
const ucontext_t* os::Solaris::get_valid_uc_in_signal_handler(Thread *thread,
  const ucontext_t *uc) {

  const ucontext_t *retuc = NULL;

  // Sometimes the topmost register windows are not properly flushed.
  // i.e., if the kernel would have needed to take a page fault
  if (uc != NULL && uc->uc_mcontext.gwins != NULL) {
    ::handle_unflushed_register_windows(uc->uc_mcontext.gwins);
  }

  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(const ucontext_t *uc) {
  address pc = (address)uc->uc_mcontext.gregs[REG_PC];
  // set npc to zero to avoid using it for safepoint, good for profiling only
  return ExtendedPC(pc);
}

void os::Solaris::ucontext_set_pc(ucontext_t* uc, address pc) {
  uc->uc_mcontext.gregs [REG_PC]  = (greg_t) pc;
  uc->uc_mcontext.gregs [REG_nPC] = (greg_t) (pc + 4);
}

// Assumes ucontext is valid
intptr_t* os::Solaris::ucontext_get_sp(const ucontext_t *uc) {
  return (intptr_t*)((intptr_t)uc->uc_mcontext.gregs[REG_SP] + STACK_BIAS);
}

// Solaris X86 only
intptr_t* os::Solaris::ucontext_get_fp(const ucontext_t *uc) {
  ShouldNotReachHere();
  return NULL;
}

address os::Solaris::ucontext_get_pc(const ucontext_t *uc) {
  return (address) uc->uc_mcontext.gregs[REG_PC];
}


// For Forte Analyzer AsyncGetCallTrace profiling support - thread
// is currently interrupted by SIGPROF.
//
// ret_fp parameter is only used by Solaris X86.
//
// The difference between this and os::fetch_frame_from_context() is that
// here we try to skip nested signal frames.
// This method is also used for stack overflow signal handling.
ExtendedPC os::Solaris::fetch_frame_from_ucontext(Thread* thread,
  const 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");

  const ucontext_t *luc = os::Solaris::get_valid_uc_in_signal_handler(thread, uc);

  return os::fetch_frame_from_context(luc, ret_sp, ret_fp);
}


// ret_fp parameter is only used by Solaris X86.
ExtendedPC os::fetch_frame_from_context(const void* ucVoid,
                    intptr_t** ret_sp, intptr_t** ret_fp) {

  ExtendedPC  epc;
  const ucontext_t *uc = (const ucontext_t*)ucVoid;

  if (uc != NULL) {
    epc = os::Solaris::ucontext_get_ExtendedPC(uc);
    if (ret_sp) *ret_sp = os::Solaris::ucontext_get_sp(uc);
  } else {
    // construct empty ExtendedPC for return value checking
    epc = ExtendedPC(NULL);
    if (ret_sp) *ret_sp = (intptr_t *)NULL;
  }

  return epc;
}

frame os::fetch_frame_from_context(const void* ucVoid) {
  intptr_t* sp;
  intptr_t* fp;
  ExtendedPC epc = fetch_frame_from_context(ucVoid, &sp, &fp);
  return frame(sp, frame::unpatchable, epc.pc());
}

frame os::fetch_frame_from_ucontext(Thread* thread, void* ucVoid) {
  intptr_t* sp;
  ExtendedPC epc = os::Solaris::fetch_frame_from_ucontext(thread, (ucontext_t*)ucVoid, &sp, NULL);
  return frame(sp, frame::unpatchable, epc.pc());
}

bool os::Solaris::get_frame_at_stack_banging_point(JavaThread* thread, ucontext_t* uc, frame* fr) {
  address pc = (address) os::Solaris::ucontext_get_pc(uc);
  if (Interpreter::contains(pc)) {
    *fr = os::fetch_frame_from_ucontext(thread, uc);
    if (!fr->is_first_java_frame()) {
      assert(fr->safe_for_sender(thread), "Safety check");
      *fr = fr->java_sender();
    }
  } else {
    // more complex code with compiled code
    assert(!Interpreter::contains(pc), "Interpreted methods should have been handled above");
    CodeBlob* cb = CodeCache::find_blob(pc);
    if (cb == NULL || !cb->is_nmethod() || cb->is_frame_complete_at(pc)) {
      // Not sure where the pc points to, fallback to default
      // stack overflow handling
      return false;
    } else {
      // Returned frame will be the caller of the method that faults on the stack bang.
      // Register window not yet rotated (happens at SAVE after stack bang), so there is no new
      // frame to go with the faulting PC. Using caller SP that is still in SP, and caller PC
      // that was written to O7 at call.
      intptr_t* sp = os::Solaris::ucontext_get_sp(uc);
      address pc = (address)uc->uc_mcontext.gregs[REG_O7];
      *fr = frame(sp, frame::unpatchable, pc);

      if (!fr->is_java_frame()) {
        assert(fr->safe_for_sender(thread), "Safety check");
        *fr = fr->java_sender();
      }
    }
  }
  assert(fr->is_java_frame(), "Safety check");
  return true;
}

frame os::get_sender_for_C_frame(frame* fr) {
  return frame(fr->sender_sp(), frame::unpatchable, fr->sender_pc());
}

// Returns an estimate of the current stack pointer. Result must be guaranteed to
// point into the calling threads stack, and be no lower than the current stack
// pointer.
address os::current_stack_pointer() {
  volatile int dummy;
  address sp = (address)&dummy + 8;     // %%%% need to confirm if this is right
  return sp;
}

frame os::current_frame() {
  intptr_t* sp = StubRoutines::Sparc::flush_callers_register_windows_func()();
  frame myframe(sp, frame::unpatchable,
                CAST_FROM_FN_PTR(address, os::current_frame));
  if (os::is_first_C_frame(&myframe)) {
    // stack is not walkable
    return frame(NULL, NULL, false);
  } else {
    return os::get_sender_for_C_frame(&myframe);
  }
}

bool os::is_allocatable(size_t bytes) {
   return true;
}

extern "C" JNIEXPORT int
JVM_handle_solaris_signal(int sig, siginfo_t* info, void* ucVoid,
                          int abort_if_unrecognized) {
  ucontext_t* uc = (ucontext_t*) ucVoid;

  Thread* t = Thread::current_or_null_safe();

  // Must do this before SignalHandlerMark, if crash protection installed we will longjmp away
  // (no destructors can be run)
  os::ThreadCrashProtection::check_crash_protection(sig, t);

  SignalHandlerMark shm(t);

  if(sig == SIGPIPE || sig == SIGXFSZ) {
    if (os::Solaris::chained_handler(sig, info, ucVoid)) {
      return true;
    } else {
      // Ignoring SIGPIPE/SIGXFSZ - see bugs 4229104 or 6499219
      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;
      }
    }
  }

  if (sig == ASYNC_SIGNAL) {
    if (thread || vmthread) {
      OSThread::SR_handler(t, uc);
      return true;
    } else if (os::Solaris::chained_handler(sig, info, ucVoid)) {
      return true;
    } else {
      // If ASYNC_SIGNAL 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");
  }

  // Handle SafeFetch faults:
  if (uc != NULL) {
    address const pc = (address) uc->uc_mcontext.gregs[REG_PC];
    if (pc && StubRoutines::is_safefetch_fault(pc)) {
      os::Solaris::ucontext_set_pc(uc, StubRoutines::continuation_for_safefetch_fault(pc));
      return 1;
    }
  }

  // decide if this trap can be handled by a stub
  address stub = NULL;

  address pc          = NULL;
  address npc         = NULL;

  //%note os_trap_1
  if (info != NULL && uc != NULL && thread != NULL) {
    // factor me: getPCfromContext
    pc  = (address) uc->uc_mcontext.gregs[REG_PC];
    npc = (address) uc->uc_mcontext.gregs[REG_nPC];

    // 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_reserved_zone(addr)) {
        // Sometimes the register windows are not properly flushed.
        if(uc->uc_mcontext.gwins != NULL) {
          ::handle_unflushed_register_windows(uc->uc_mcontext.gwins);
        }
        if (thread->thread_state() == _thread_in_Java) {
          if (thread->in_stack_reserved_zone(addr)) {
            frame fr;
            if (os::Solaris::get_frame_at_stack_banging_point(thread, uc, &fr)) {
              assert(fr.is_java_frame(), "Must be a Java frame");
              frame activation = SharedRuntime::look_for_reserved_stack_annotated_method(thread, fr);
              if (activation.sp() != NULL) {
                thread->disable_stack_reserved_zone();
                RegisterMap map(thread);
                int frame_size = activation.frame_size(&map);
                thread->set_reserved_stack_activation((address)(((address)activation.sp()) - STACK_BIAS));
                return true;
              }
            }
          }
          // Throw a stack overflow exception.  Guard pages will be reenabled
          // while unwinding the stack.
          thread->disable_stack_yellow_reserved_zone();
          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.
          thread->disable_stack_yellow_reserved_zone();
          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.");
        // Sometimes the register windows are not properly flushed.
        if(uc->uc_mcontext.gwins != NULL) {
          ::handle_unflushed_register_windows(uc->uc_mcontext.gwins);
        }
      }
    }


    if (thread->thread_state() == _thread_in_vm) {
      if (sig == SIGBUS && thread->doing_unsafe_access()) {
        stub = SharedRuntime::handle_unsafe_access(thread, npc);
      }
    }

    else if (thread->thread_state() == _thread_in_Java) {
      // Java thread running in Java code => find exception handler if any
      // a fault inside compiled code, the interpreter, or a stub

      // Support Safepoint Polling
      if (sig == SIGSEGV && os::is_poll_address((address)info->si_addr)) {
        stub = SharedRuntime::get_poll_stub(pc);
      }

      // Not needed on x86 solaris because verify_oops doesn't generate
      // SEGV/BUS like sparc does.
      if ( (sig == SIGSEGV || sig == SIGBUS)
           && pc >= MacroAssembler::_verify_oop_implicit_branch[0]
           && pc <  MacroAssembler::_verify_oop_implicit_branch[1] ) {
        stub     =  MacroAssembler::_verify_oop_implicit_branch[2];
        warning("fixed up memory fault in +VerifyOops at address " INTPTR_FORMAT, info->si_addr);
      }

      // This is not factored because on x86 solaris the patching for
      // zombies does not generate a SEGV.
      else if (sig == SIGSEGV && nativeInstruction_at(pc)->is_zombie()) {
        // zombie method (ld [%g0],%o7 instruction)
        stub = SharedRuntime::get_handle_wrong_method_stub();

        // At the stub it needs to look like a call from the caller of this
        // method (not a call from the segv site).
        pc = (address)uc->uc_mcontext.gregs[REG_O7];
      }
      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);
        CompiledMethod* nm = cb->as_compiled_method_or_null();
        if (nm != NULL && nm->has_unsafe_access()) {
          stub = SharedRuntime::handle_unsafe_access(thread, npc);
        }
      }

      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);
      }
      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);
      }
#ifdef COMPILER2
      else if (sig == SIGILL && nativeInstruction_at(pc)->is_ic_miss_trap()) {
#ifdef ASSERT
  #ifdef TIERED
        CodeBlob* cb = CodeCache::find_blob_unsafe(pc);
        assert(cb->is_compiled_by_c2(), "Wrong compiler");
  #endif // TIERED
#endif // ASSERT
        // Inline cache missed and user trap "Tne G0+ST_RESERVED_FOR_USER_0+2" taken.
        stub = SharedRuntime::get_ic_miss_stub();
        // At the stub it needs to look like a call from the caller of this
        // method (not a call from the segv site).
        pc = (address)uc->uc_mcontext.gregs[REG_O7];
      }
#endif  // COMPILER2

      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 just return.
    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;
    }
  }

  if (stub != NULL) {
    // save all thread context in case we need to restore it

    thread->set_saved_exception_pc(pc);
    thread->set_saved_exception_npc(npc);

    // simulate a branch to the stub (a "call" in the safepoint stub case)
    // factor me: setPC
    os::Solaris::ucontext_set_pc(uc, stub);

    return true;
  }

  // signal-chaining
  if (os::Solaris::chained_handler(sig, info, ucVoid)) {
    return true;
  }

  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 occurred under user-defined signal handler " INTPTR_FORMAT, sig, (intptr_t)sighand);
    }
  }

  if (pc == NULL && uc != NULL) {
    pc = (address) uc->uc_mcontext.gregs[REG_PC];
  }

  // Sometimes the register windows are not properly flushed.
  if(uc->uc_mcontext.gwins != NULL) {
    ::handle_unflushed_register_windows(uc->uc_mcontext.gwins);
  }

  // unmask current signal
  sigset_t newset;
  sigemptyset(&newset);
  sigaddset(&newset, sig);
  sigprocmask(SIG_UNBLOCK, &newset, NULL);

  // Determine which sort of error to throw.  Out of swap may signal
  // on the thread stack, which could get a mapping error when touched.
  address addr = (address) info->si_addr;
  if (sig == SIGBUS && info->si_code == BUS_OBJERR && info->si_errno == ENOMEM) {
    vm_exit_out_of_memory(0, OOM_MMAP_ERROR, "Out of swap space to map in thread stack.");
  }

  VMError::report_and_die(t, sig, pc, info, ucVoid);

  ShouldNotReachHere();
  return false;
}

void os::print_context(outputStream *st, const void *context) {
  if (context == NULL) return;

  const ucontext_t *uc = (const ucontext_t*)context;
  st->print_cr("Registers:");

  st->print_cr(" G1=" INTPTR_FORMAT " G2=" INTPTR_FORMAT
               " G3=" INTPTR_FORMAT " G4=" INTPTR_FORMAT,
            uc->uc_mcontext.gregs[REG_G1],
            uc->uc_mcontext.gregs[REG_G2],
            uc->uc_mcontext.gregs[REG_G3],
            uc->uc_mcontext.gregs[REG_G4]);
  st->print_cr(" G5=" INTPTR_FORMAT " G6=" INTPTR_FORMAT
               " G7=" INTPTR_FORMAT " Y=" INTPTR_FORMAT,
            uc->uc_mcontext.gregs[REG_G5],
            uc->uc_mcontext.gregs[REG_G6],
            uc->uc_mcontext.gregs[REG_G7],
            uc->uc_mcontext.gregs[REG_Y]);
  st->print_cr(" O0=" INTPTR_FORMAT " O1=" INTPTR_FORMAT
               " O2=" INTPTR_FORMAT " O3=" INTPTR_FORMAT,
                 uc->uc_mcontext.gregs[REG_O0],
                 uc->uc_mcontext.gregs[REG_O1],
                 uc->uc_mcontext.gregs[REG_O2],
                 uc->uc_mcontext.gregs[REG_O3]);
  st->print_cr(" O4=" INTPTR_FORMAT " O5=" INTPTR_FORMAT
               " O6=" INTPTR_FORMAT " O7=" INTPTR_FORMAT,
            uc->uc_mcontext.gregs[REG_O4],
            uc->uc_mcontext.gregs[REG_O5],
            uc->uc_mcontext.gregs[REG_O6],
            uc->uc_mcontext.gregs[REG_O7]);


  intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc);
  st->print_cr(" L0=" INTPTR_FORMAT " L1=" INTPTR_FORMAT
               " L2=" INTPTR_FORMAT " L3=" INTPTR_FORMAT,
               sp[L0->sp_offset_in_saved_window()],
               sp[L1->sp_offset_in_saved_window()],
               sp[L2->sp_offset_in_saved_window()],
               sp[L3->sp_offset_in_saved_window()]);
  st->print_cr(" L4=" INTPTR_FORMAT " L5=" INTPTR_FORMAT
               " L6=" INTPTR_FORMAT " L7=" INTPTR_FORMAT,
               sp[L4->sp_offset_in_saved_window()],
               sp[L5->sp_offset_in_saved_window()],
               sp[L6->sp_offset_in_saved_window()],
               sp[L7->sp_offset_in_saved_window()]);
  st->print_cr(" I0=" INTPTR_FORMAT " I1=" INTPTR_FORMAT
               " I2=" INTPTR_FORMAT " I3=" INTPTR_FORMAT,
               sp[I0->sp_offset_in_saved_window()],
               sp[I1->sp_offset_in_saved_window()],
               sp[I2->sp_offset_in_saved_window()],
               sp[I3->sp_offset_in_saved_window()]);
  st->print_cr(" I4=" INTPTR_FORMAT " I5=" INTPTR_FORMAT
               " I6=" INTPTR_FORMAT " I7=" INTPTR_FORMAT,
               sp[I4->sp_offset_in_saved_window()],
               sp[I5->sp_offset_in_saved_window()],
               sp[I6->sp_offset_in_saved_window()],
               sp[I7->sp_offset_in_saved_window()]);

  st->print_cr(" PC=" INTPTR_FORMAT " nPC=" INTPTR_FORMAT,
            uc->uc_mcontext.gregs[REG_PC],
            uc->uc_mcontext.gregs[REG_nPC]);
  st->cr();
  st->cr();

  st->print_cr("Top of Stack: (sp=" PTR_FORMAT ")", sp);
  print_hex_dump(st, (address)sp, (address)(sp + 32), 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();
  print_instructions(st, pc, sizeof(char));
  st->cr();
}

void os::print_register_info(outputStream *st, const void *context) {
  if (context == NULL) return;

  const ucontext_t *uc = (const ucontext_t*)context;
  intptr_t *sp = (intptr_t *)os::Solaris::ucontext_get_sp(uc);

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

  // this is only for the "general purpose" registers
  st->print("G1="); print_location(st, uc->uc_mcontext.gregs[REG_G1]);
  st->print("G2="); print_location(st, uc->uc_mcontext.gregs[REG_G2]);
  st->print("G3="); print_location(st, uc->uc_mcontext.gregs[REG_G3]);
  st->print("G4="); print_location(st, uc->uc_mcontext.gregs[REG_G4]);
  st->print("G5="); print_location(st, uc->uc_mcontext.gregs[REG_G5]);
  st->print("G6="); print_location(st, uc->uc_mcontext.gregs[REG_G6]);
  st->print("G7="); print_location(st, uc->uc_mcontext.gregs[REG_G7]);
  st->cr();

  st->print("O0="); print_location(st, uc->uc_mcontext.gregs[REG_O0]);
  st->print("O1="); print_location(st, uc->uc_mcontext.gregs[REG_O1]);
  st->print("O2="); print_location(st, uc->uc_mcontext.gregs[REG_O2]);
  st->print("O3="); print_location(st, uc->uc_mcontext.gregs[REG_O3]);
  st->print("O4="); print_location(st, uc->uc_mcontext.gregs[REG_O4]);
  st->print("O5="); print_location(st, uc->uc_mcontext.gregs[REG_O5]);
  st->print("O6="); print_location(st, uc->uc_mcontext.gregs[REG_O6]);
  st->print("O7="); print_location(st, uc->uc_mcontext.gregs[REG_O7]);
  st->cr();

  st->print("L0="); print_location(st, sp[L0->sp_offset_in_saved_window()]);
  st->print("L1="); print_location(st, sp[L1->sp_offset_in_saved_window()]);
  st->print("L2="); print_location(st, sp[L2->sp_offset_in_saved_window()]);
  st->print("L3="); print_location(st, sp[L3->sp_offset_in_saved_window()]);
  st->print("L4="); print_location(st, sp[L4->sp_offset_in_saved_window()]);
  st->print("L5="); print_location(st, sp[L5->sp_offset_in_saved_window()]);
  st->print("L6="); print_location(st, sp[L6->sp_offset_in_saved_window()]);
  st->print("L7="); print_location(st, sp[L7->sp_offset_in_saved_window()]);
  st->cr();

  st->print("I0="); print_location(st, sp[I0->sp_offset_in_saved_window()]);
  st->print("I1="); print_location(st, sp[I1->sp_offset_in_saved_window()]);
  st->print("I2="); print_location(st, sp[I2->sp_offset_in_saved_window()]);
  st->print("I3="); print_location(st, sp[I3->sp_offset_in_saved_window()]);
  st->print("I4="); print_location(st, sp[I4->sp_offset_in_saved_window()]);
  st->print("I5="); print_location(st, sp[I5->sp_offset_in_saved_window()]);
  st->print("I6="); print_location(st, sp[I6->sp_offset_in_saved_window()]);
  st->print("I7="); print_location(st, sp[I7->sp_offset_in_saved_window()]);
  st->cr();
}

void os::Solaris::init_thread_fpu_state(void) {
    // Nothing needed on Sparc.
}

#ifndef PRODUCT
void os::verify_stack_alignment() {
}
#endif

int os::extra_bang_size_in_bytes() {
  // SPARC does not require an additional stack bang.
  return 0;
}