more TheRealMDoerr suggestions

src/hotspot/cpu/zero/nativeInst_zero.cpp

@@ -1,30 +0,0 @@
-/*
- * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
- * Copyright 2008 Red Hat, Inc.
- * 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.
- *
- */
-
-#include "asm/assembler.inline.hpp"
-#include "entry_zero.hpp"
-#include "interpreter/zero/zeroInterpreter.hpp"
-#include "nativeInst_zero.hpp"
-#include "runtime/sharedRuntime.hpp"

src/hotspot/os_cpu/linux_arm/os_linux_arm.cpp

@@ -359,11 +359,6 @@ bool PosixSignals::pd_hotspot_signal_handler(int sig, siginfo_t* info,
           stub = SharedRuntime::continuation_for_implicit_exception(
               thread, pc, SharedRuntime::IMPLICIT_NULL);
         }
-      } else if (sig == SIGILL &&
-                 *(int*)pc ==
-                     NativeInstruction::not_entrant_illegal_instruction) {
-        // Not entrant
-        stub = SharedRuntime::get_handle_wrong_method_stub();
       }
     } else if ((thread->thread_state() == _thread_in_vm ||
                 thread->thread_state() == _thread_in_native) &&

src/hotspot/share/gc/shared/barrierSetNMethod.cpp

@@ -246,7 +246,10 @@ void BarrierSetNMethod::make_not_entrant(nmethod* nm) {
   // Enter critical section.  Does not block for safepoint.
   ConditionalMutexLocker ml(NMethodEntryBarrier_lock, !NMethodEntryBarrier_lock->owned_by_self(), Mutex::_no_safepoint_check_flag);
   int value = guard_value(nm) | not_entrant;
-  set_guard_value(nm, value);
+  if (guard_value(nm) != value) {
+    // Patch the code only if needed.
+    set_guard_value(nm, value);
+  }
 }
 
 bool BarrierSetNMethod::is_not_entrant(nmethod* nm) {