src/hotspot/cpu/x86/sharedRuntime_x86_32.cpp

@@ -2005,16 +2005,13 @@
     __ orptr(swap_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
 
     // Save (object->mark() | 1) into BasicLock's displaced header
     __ movptr(Address(lock_reg, mark_word_offset), swap_reg);
 
-    if (os::is_MP()) {
-      __ lock();
-    }
-
     // src -> dest iff dest == rax, else rax, <- dest
     // *obj_reg = lock_reg iff *obj_reg == rax, else rax, = *(obj_reg)
+    __ lock();
     __ cmpxchgptr(lock_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
     __ jcc(Assembler::equal, lock_done);
 
     // Test if the oopMark is an obvious stack pointer, i.e.,
     //  1) (mark & 3) == 0, and

@@ -2089,11 +2086,10 @@
   //     VM thread changes sync state to synchronizing and suspends threads for GC.
   //     Thread A is resumed to finish this native method, but doesn't block here since it
   //     didn't see any synchronization is progress, and escapes.
   __ movl(Address(thread, JavaThread::thread_state_offset()), _thread_in_native_trans);
 
-  if(os::is_MP()) {
     if (UseMembar) {
       // Force this write out before the read below
       __ membar(Assembler::Membar_mask_bits(
            Assembler::LoadLoad | Assembler::LoadStore |
            Assembler::StoreLoad | Assembler::StoreStore));

@@ -2102,11 +2098,10 @@
       // We use the current thread pointer to calculate a thread specific
       // offset to write to within the page. This minimizes bus traffic
       // due to cache line collision.
       __ serialize_memory(thread, rcx);
     }
-  }
 
   if (AlwaysRestoreFPU) {
     // Make sure the control word is correct.
     __ fldcw(ExternalAddress(StubRoutines::addr_fpu_cntrl_wrd_std()));
   }

@@ -2197,16 +2192,13 @@
 
     // get address of the stack lock
     __ lea(rax, Address(rbp, lock_slot_rbp_offset));
 
     // Atomic swap old header if oop still contains the stack lock
-    if (os::is_MP()) {
-    __ lock();
-    }
-
     // src -> dest iff dest == rax, else rax, <- dest
     // *obj_reg = rbx, iff *obj_reg == rax, else rax, = *(obj_reg)
+    __ lock();
     __ cmpxchgptr(rbx, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
     __ jcc(Assembler::notEqual, slow_path_unlock);
 
     // slow path re-enters here
     __ bind(unlock_done);