1 /*
 2  * Copyright (c) 2018, 2022, 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/zNMethod.hpp"
30 #include "gc/z/zThreadLocalData.hpp"
31 #include "logging/log.hpp"
32 #include "runtime/threadWXSetters.inline.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   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current()));
45 
46   if (nm->is_unloading()) {
47     // We don't need to take the lock when unlinking nmethods from
48     // the Method, because it is only concurrently unlinked by
49     // the entry barrier, which acquires the per nmethod lock.
50     nm->unlink_from_method();
51 
52     // We can end up calling nmethods that are unloading
53     // since we clear compiled ICs lazily. Returning false
54     // will re-resovle the call and update the compiled IC.
55     return false;
56   }
57 
58   // Heal oops
59   ZNMethod::nmethod_oops_barrier(nm);
60 
61 
62   // CodeCache unloading support
63   nm->mark_as_maybe_on_stack();
64 
65   // Disarm
66   disarm(nm);
67 
68   return true;
69 }
70 
71 int* ZBarrierSetNMethod::disarmed_guard_value_address() const {
72   return (int*)ZAddressBadMaskHighOrderBitsAddr;
73 }
74 
75 ByteSize ZBarrierSetNMethod::thread_disarmed_guard_value_offset() const {
76   return ZThreadLocalData::nmethod_disarmed_offset();
77 }