8356556: AArch64: No need for acquire fence in safepoint poll in FFM

src/hotspot/cpu/aarch64/aarch64.ad

@@ -1888,7 +1888,7 @@ void MachEpilogNode::emit(C2_MacroAssembler *masm, PhaseRegAlloc *ra_) const {
       code_stub = &stub->entry();
     }
     __ relocate(relocInfo::poll_return_type);
-    __ safepoint_poll(*code_stub, true /* at_return */, false /* acquire */, true /* in_nmethod */);
+    __ safepoint_poll(*code_stub, true /* at_return */, true /* in_nmethod */);
   }
 }
 

src/hotspot/cpu/aarch64/c1_LIRAssembler_aarch64.cpp

@@ -483,7 +483,7 @@ void LIR_Assembler::return_op(LIR_Opr result, C1SafepointPollStub* code_stub) {
 
   code_stub->set_safepoint_offset(__ offset());
   __ relocate(relocInfo::poll_return_type);
-  __ safepoint_poll(*code_stub->entry(), true /* at_return */, false /* acquire */, true /* in_nmethod */);
+  __ safepoint_poll(*code_stub->entry(), true /* at_return */, true /* in_nmethod */);
   __ ret(lr);
 }
 

src/hotspot/cpu/aarch64/downcallLinker_aarch64.cpp

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2019, 2025 Arm Limited. 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
@@ -289,7 +289,7 @@ void DowncallLinker::StubGenerator::generate() {
 
     __ verify_sve_vector_length(tmp1);
 
-    __ safepoint_poll(L_safepoint_poll_slow_path, true /* at_return */, true /* acquire */, false /* in_nmethod */, tmp1);
+    __ safepoint_poll(L_safepoint_poll_slow_path, true /* at_return */, false /* in_nmethod */, tmp1);
 
     __ ldrw(tmp1, Address(rthread, JavaThread::suspend_flags_offset()));
     __ cbnzw(tmp1, L_safepoint_poll_slow_path);

src/hotspot/cpu/aarch64/interp_masm_aarch64.cpp

@@ -484,7 +484,7 @@ void InterpreterMacroAssembler::remove_activation(
   // the stack, will call InterpreterRuntime::at_unwind.
   Label slow_path;
   Label fast_path;
-  safepoint_poll(slow_path, true /* at_return */, false /* acquire */, false /* in_nmethod */);
+  safepoint_poll(slow_path, true /* at_return */, false /* in_nmethod */);
   br(Assembler::AL, fast_path);
   bind(slow_path);
   push(state);

src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp

@@ -553,13 +553,8 @@ address MacroAssembler::target_addr_for_insn_or_null(address insn_addr, unsigned
   return MacroAssembler::target_addr_for_insn(insn_addr, insn);
 }
 
-void MacroAssembler::safepoint_poll(Label& slow_path, bool at_return, bool acquire, bool in_nmethod, Register tmp) {
-  if (acquire) {
-    lea(tmp, Address(rthread, JavaThread::polling_word_offset()));
-    ldar(tmp, tmp);
-  } else {
-    ldr(tmp, Address(rthread, JavaThread::polling_word_offset()));
-  }
+void MacroAssembler::safepoint_poll(Label& slow_path, bool at_return, bool in_nmethod, Register tmp) {
+  ldr(tmp, Address(rthread, JavaThread::polling_word_offset()));
   if (at_return) {
     // Note that when in_nmethod is set, the stack pointer is incremented before the poll. Therefore,
     // we may safely use the sp instead to perform the stack watermark check.

src/hotspot/cpu/aarch64/macroAssembler_aarch64.hpp

@@ -120,7 +120,7 @@ class MacroAssembler: public Assembler {
  virtual void check_and_handle_popframe(Register java_thread);
  virtual void check_and_handle_earlyret(Register java_thread);
 
-  void safepoint_poll(Label& slow_path, bool at_return, bool acquire, bool in_nmethod, Register tmp = rscratch1);
+  void safepoint_poll(Label& slow_path, bool at_return, bool in_nmethod, Register tmp = rscratch1);
   void rt_call(address dest, Register tmp = rscratch1);
 
   // Load Effective Address

src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp

@@ -1875,8 +1875,7 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
 
   // Check for safepoint operation in progress and/or pending suspend requests.
   {
-    // No need for acquire as Java threads always disarm themselves.
-    __ safepoint_poll(safepoint_in_progress, true /* at_return */, false /* acquire */, false /* in_nmethod */);
+    __ safepoint_poll(safepoint_in_progress, true /* at_return */, false /* in_nmethod */);
     __ ldrw(rscratch1, Address(rthread, JavaThread::suspend_flags_offset()));
     __ cbnzw(rscratch1, safepoint_in_progress);
     __ bind(safepoint_in_progress_done);

src/hotspot/cpu/aarch64/templateInterpreterGenerator_aarch64.cpp

@@ -1013,7 +1013,7 @@ address TemplateInterpreterGenerator::generate_CRC32_update_entry() {
 
   Label slow_path;
   // If we need a safepoint check, generate full interpreter entry.
-  __ safepoint_poll(slow_path, false /* at_return */, false /* acquire */, false /* in_nmethod */);
+  __ safepoint_poll(slow_path, false /* at_return */, false /* in_nmethod */);
 
   // We don't generate local frame and don't align stack because
   // we call stub code and there is no safepoint on this path.
@@ -1060,7 +1060,7 @@ address TemplateInterpreterGenerator::generate_CRC32_updateBytes_entry(AbstractI
 
   Label slow_path;
   // If we need a safepoint check, generate full interpreter entry.
-  __ safepoint_poll(slow_path, false /* at_return */, false /* acquire */, false /* in_nmethod */);
+  __ safepoint_poll(slow_path, false /* at_return */, false /* in_nmethod */);
 
   // We don't generate local frame and don't align stack because
   // we call stub code and there is no safepoint on this path.
@@ -1449,8 +1449,7 @@ address TemplateInterpreterGenerator::generate_native_entry(bool synchronized) {
   {
     Label L, Continue;
 
-    // No need for acquire as Java threads always disarm themselves.
-    __ safepoint_poll(L, true /* at_return */, false /* acquire */, false /* in_nmethod */);
+    __ safepoint_poll(L, true /* at_return */, false /* in_nmethod */);
     __ ldrw(rscratch2, Address(rthread, JavaThread::suspend_flags_offset()));
     __ cbz(rscratch2, Continue);
     __ bind(L);