src/hotspot/os_cpu/linux_s390/atomic_linux_s390.hpp

rev 49845 : 8202080: Introduce ordering semantics for Atomic::add
Reviewed-by:

@@ -71,16 +71,17 @@
 template<size_t byte_size>
 struct Atomic::PlatformAdd
   : Atomic::AddAndFetch<Atomic::PlatformAdd<byte_size> >
 {
   template<typename I, typename D>
-  D add_and_fetch(I add_value, D volatile* dest) const;
+  D add_and_fetch(I add_value, D volatile* dest, cmpxchg_memory_order order) const;
 };
 
 template<>
 template<typename I, typename D>
-inline D Atomic::PlatformAdd<4>::add_and_fetch(I inc, D volatile* dest) const {
+inline D Atomic::PlatformAdd<4>::add_and_fetch(I inc, D volatile* dest,
+                                               cmpxchg_memory_order order) const {
   STATIC_ASSERT(4 == sizeof(I));
   STATIC_ASSERT(4 == sizeof(D));
 
   D old, upd;
 

@@ -104,10 +105,13 @@
       //---<  inputs  >---
       : [inc]  "a"   (inc)    // read-only.
       //---<  clobbered  >---
       : "cc", "r0", "r2", "r3", "memory"
     );
+    if (order == memory_order_conservative) {
+      __asm__ __volatile__ ("bcr 14, 0" : : : "memory");
+    }
   } else {
     __asm__ __volatile__ (
       "   LLGF     %[old],%[mem]           \n\t" // get old value
       "0: LA       %[upd],0(%[inc],%[old]) \n\t" // calc result
       "   CS       %[old],%[upd],%[mem]    \n\t" // try to xchg res with mem

@@ -127,11 +131,12 @@
 }
 
 
 template<>
 template<typename I, typename D>
-inline D Atomic::PlatformAdd<8>::add_and_fetch(I inc, D volatile* dest) const {
+inline D Atomic::PlatformAdd<8>::add_and_fetch(I inc, D volatile* dest,
+                                               cmpxchg_memory_order order) const {
   STATIC_ASSERT(8 == sizeof(I));
   STATIC_ASSERT(8 == sizeof(D));
 
   D old, upd;
 

@@ -155,10 +160,13 @@
       //---<  inputs  >---
       : [inc]  "a"   (inc)    // read-only.
       //---<  clobbered  >---
       : "cc", "r0", "r2", "r3", "memory"
     );
+    if (order == memory_order_conservative) {
+      __asm__ __volatile__ ("bcr 14, 0" : : : "memory");
+    }
   } else {
     __asm__ __volatile__ (
       "   LG       %[old],%[mem]           \n\t" // get old value
       "0: LA       %[upd],0(%[inc],%[old]) \n\t" // calc result
       "   CSG      %[old],%[upd],%[mem]    \n\t" // try to xchg res with mem