diff --git a/repos/base-hw/lib/mk/x86/core.inc b/repos/base-hw/lib/mk/x86/core.inc
index 79a1d7ce9..3c30ad66e 100644
--- a/repos/base-hw/lib/mk/x86/core.inc
+++ b/repos/base-hw/lib/mk/x86/core.inc
@@ -9,11 +9,12 @@
 INC_DIR += $(REP_DIR)/src/core/include/spec/x86
 
 # add C++ sources
-SRC_CC += platform_services.cc
 SRC_CC += spec/x86/platform_support.cc
 SRC_CC += spec/x86/kernel/thread.cc
 SRC_CC += spec/x86/kernel/cpu.cc
 SRC_CC += kernel/vm_thread.cc
+SRC_CC += x86/io_port_session_component.cc
+SRC_CC += x86/platform_services.cc
 
 # include less specific configuration
 include $(REP_DIR)/lib/mk/core.inc