diff --git a/Makefile.base b/Makefile.base
index 582ae88f3..1def37be5 100644
--- a/Makefile.base
+++ b/Makefile.base
@@ -22,16 +22,33 @@ ${DIRS:%=ALL--%}:
 ${DIRS:%=CLEAN--%}:
 	$(QQ)"$(MAKE)" -C ${@:CLEAN--%=%} clean
 
-ifeq ($(strip $(SRC)),)
+## submodules
+ifeq (1, $(SUBMODULES))
+    # don't use *.c as SRC if SRC is empty (e.g., no module selected)
+    NO_AUTO_SRC := 1
+
+    # allow different submodule basename (e.g., MODULE=cpu_periph_common, but match just periph_%)
+    BASE_MODULE ?= $(MODULE)
+
+    # for each $(BASE_MODULE)_<name> in USEMODULE, add <name>.c to SRC
+    SRC += $(patsubst $(BASE_MODULE)_%,%.c,$(filter $(BASE_MODULE)_%,$(USEMODULE)))
+
+    # don't fail if a selected *.c file does not exist
+    ifeq (1, $(SUBMODULES_NOFORCE))
+        SRC := $(filter $(SRC), $(wildcard *.c))
+    endif
+endif
+
+ifeq ($(strip $(SRC))$(NO_AUTO_SRC),)
     SRC := $(filter-out $(SRC_NOLTO), $(wildcard *.c))
 endif
-ifeq ($(strip $(SRCXX)),)
+ifeq ($(strip $(SRCXX))$(NO_AUTO_SRC),)
     SRCXX := $(wildcard *.cpp)
 endif
-ifeq ($(strip $(ASMSRC)),)
+ifeq ($(strip $(ASMSRC))$(NO_AUTO_SRC),)
     ASMSRC := $(wildcard *.s)
 endif
-ifeq ($(strip $(ASSMSRC)),)
+ifeq ($(strip $(ASSMSRC))$(NO_AUTO_SRC),)
     ASSMSRC := $(wildcard *.S)
 endif
 
diff --git a/Makefile.pseudomodules b/Makefile.pseudomodules
index a91c8c63e..2602805b4 100644
--- a/Makefile.pseudomodules
+++ b/Makefile.pseudomodules
@@ -3,9 +3,7 @@ PSEUDOMODULES += conn
 PSEUDOMODULES += conn_ip
 PSEUDOMODULES += conn_tcp
 PSEUDOMODULES += conn_udp
-PSEUDOMODULES += core_msg
-PSEUDOMODULES += core_mbox
-PSEUDOMODULES += core_thread_flags
+PSEUDOMODULES += core_%
 PSEUDOMODULES += emb6_router
 PSEUDOMODULES += gnrc_ipv6_default
 PSEUDOMODULES += gnrc_ipv6_router
diff --git a/core/Makefile b/core/Makefile
index 48422e909..4f1236694 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1 +1,7 @@
+# exclude submodule sources from *.c wildcard source selection
+SRC := $(filter-out mbox.c msg.c thread_flags.c,$(wildcard *.c))
+
+# enable submodules
+SUBMODULES := 1
+
 include $(RIOTBASE)/Makefile.base
diff --git a/core/mbox.c b/core/mbox.c
index 7c14f3514..bd5e32415 100644
--- a/core/mbox.c
+++ b/core/mbox.c
@@ -28,8 +28,6 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-#ifdef MODULE_CORE_MBOX
-
 static void _wake_waiter(thread_t *thread, unsigned irqstate)
 {
     sched_set_status(thread, STATUS_PENDING);
@@ -122,5 +120,3 @@ int _mbox_get(mbox_t *mbox, msg_t *msg, int blocking)
         return 0;
     }
 }
-
-#endif /* MODULE_CORE_MBOX */
diff --git a/core/msg.c b/core/msg.c
index 4ab206141..190244cca 100644
--- a/core/msg.c
+++ b/core/msg.c
@@ -34,8 +34,6 @@
 #include "debug.h"
 #include "thread.h"
 
-#ifdef MODULE_CORE_MSG
-
 static int _msg_receive(msg_t *m, int block);
 static int _msg_send(msg_t *m, kernel_pid_t target_pid, bool block, unsigned state);
 
@@ -409,5 +407,3 @@ void msg_queue_print(void)
 
     irq_restore(state);
 }
-
-#endif /* MODULE_CORE_MSG */
diff --git a/core/thread_flags.c b/core/thread_flags.c
index 9396c31e3..281a59230 100644
--- a/core/thread_flags.c
+++ b/core/thread_flags.c
@@ -26,7 +26,6 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-#ifdef MODULE_CORE_THREAD_FLAGS
 static thread_flags_t _thread_flags_clear_atomic(thread_t *thread, thread_flags_t mask)
 {
     unsigned state = irq_disable();
@@ -133,4 +132,3 @@ void thread_flags_set(thread_t *thread, thread_flags_t mask)
         irq_restore(state);
     }
 }
-#endif /* MODULE_CORE_THREAD_FLAGS */