1 /*
   2  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "code/nmethod.hpp"
  26 #include "gc/z/zBarrierSetNMethod.hpp"
  27 #include "gc/z/zGlobals.hpp"
  28 #include "gc/z/zLock.inline.hpp"
  29 #include "gc/z/zOopClosures.hpp"
  30 #include "gc/z/zNMethod.hpp"
  31 #include "gc/z/zThreadLocalData.hpp"
  32 #include "logging/log.hpp"
  33 
  34 bool ZBarrierSetNMethod::nmethod_entry_barrier(nmethod* nm) {
  35   ZLocker<ZReentrantLock> locker(ZNMethod::lock_for_nmethod(nm));
  36   log_trace(nmethod, barrier)("Entered critical zone for %p", nm);
  37 
  38   if (!is_armed(nm)) {
  39     // Some other thread got here first and healed the oops
  40     // and disarmed the nmethod.
  41     return true;
  42   }
  43 
  44   if (nm->is_unloading()) {
  45     // We don't need to take the lock when unlinking nmethods from
  46     // the Method, because it is only concurrently unlinked by
  47     // the entry barrier, which acquires the per nmethod lock.
  48     nm->unlink_from_method();
  49 
  50     // We can end up calling nmethods that are unloading
  51     // since we clear compiled ICs lazily. Returning false
  52     // will re-resovle the call and update the compiled IC.
  53     return false;
  54   }
  55 
  56   // Heal oops and disarm
  57   ZNMethodOopClosure cl;
  58   ZNMethod::nmethod_oops_do(nm, &cl);
  59   disarm(nm);
  60 
  61   return true;
  62 }
  63 
  64 int ZBarrierSetNMethod::disarmed_value() const {
  65   // We override the default BarrierSetNMethod::disarmed_value() since
  66   // this can be called by GC threads, which doesn't keep an up to date
  67   // address_bad_mask.
  68   const uintptr_t disarmed_addr = ((uintptr_t)&ZAddressBadMask) + ZNMethodDisarmedOffset;
  69   return *((int*)disarmed_addr);
  70 }
  71 
  72 ByteSize ZBarrierSetNMethod::thread_disarmed_offset() const {
  73   return ZThreadLocalData::nmethod_disarmed_offset();
  74 }
  75 
  76 intptr_t ZBarrierSetNMethod::disarmed_address() const {
  77   ShouldNotReachHere();
  78   return (intptr_t)NULL;
  79 }