Index: head/sys/dev/sym/sym_hipd.c
===================================================================
--- head/sys/dev/sym/sym_hipd.c
+++ head/sys/dev/sym/sym_hipd.c
@@ -136,6 +136,8 @@
 #define MEMORY_BARRIER()	__asm__ volatile("membar #Sync" : : : "memory")
 #elif	defined	__arm__
 #define MEMORY_BARRIER()	dmb()
+#elif	defined	__aarch64__
+#define MEMORY_BARRIER()	dmb(sy)
 #else
 #error	"Not supported platform"
 #endif