Messages in this thread Patch in this message | | | Date | Mon, 22 Jan 2018 13:46:07 -0800 | From | Jakub Kicinski <> | Subject | Mutli-directory module Makefiles |
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Hi!
in drivers/net/ethernet/netronome/nfp there is a module which is built from C sources in 4 directories. What is the best way to handle that?
Currently we just add all the objects in one Makefile:
nfp-objs := \ nfpcore/nfp6000_pcie.o \ nfpcore/nfp_cppcore.o \ etc.
However, this makes it impossible to build a single object in subdirs:
$ make drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.o scripts/Makefile.build:45: drivers/net/ethernet/netronome/nfp/nfpcore/Makefile: No such file or directory make[2]: *** No rule to make target 'drivers/net/ethernet/netronome/nfp/nfpcore/Makefile'. Stop.
Documentation/kbuild/modules.txt also contains an unclear remark that this is not recommended (or is it about the use of $(src)?):
--- 4.3 Several Subdirectories ... To build the module complex.ko, we then need the following kbuild file:
--> filename: Kbuild obj-m := complex.o complex-y := src/complex_main.o complex-y += src/hal/hardwareif.o
ccflags-y := -I$(src)/include ccflags-y += -I$(src)/src/hal/include
As you can see, kbuild knows how to handle object files located in other directories. The trick is to specify the directory relative to the kbuild file's location. **That being said, this is NOT recommended practice.**
Making the include optional would work:
diff --git a/scripts/Makefile.build b/scripts/Makefile.build @@ -42,7 +42,7 @@ save-cflags := $(CFLAGS) # The filename Kbuild has precedence over Makefile kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile) -include $(kbuild-file) +-include $(kbuild-file) # If the save-* variables changed error out ifeq ($(KBUILD_NOPEDANTIC),) Or we could create empty Makefiles in subdirectories... Is there a better way of handling this? Which is preferred?
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