| Message ID | 20240402153028.1378868-1-vchernou@cisco.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add MO(mod objs) variable to process ext modules with subdirs | expand |
Hi, On 4/2/24 8:30 AM, Valerii Chernous wrote: > The change allow to build external modules with nested makefiles. > With current unofficial way(using "src" variable) it is posible to build possible > external(out of tree) kernel module with separating source and build > artifacts dirs but with nested makefiles it doesn't work properly. > Build system trap to recursion inside makefiles, articafts output dir artifacts > path grow with each iteration until exceed max path len and build failed > Providing "MO" variable and using "override" directive with declaring > "src" variable solve the problem > Usage example: > make -C KERNEL_SOURCE_TREE MO=BUILD_OUT_DIR M=EXT_MOD_SRC_DIR modules > > Cc: xe-linux-external@cisco.com > Cc: Valerii Chernous <vchernou@cisco.com> > Signed-off-by: Valerii Chernous <vchernou@cisco.com> > --- > Makefile | 17 +++++++++++++++++ > scripts/Makefile.build | 7 +++++++ > 2 files changed, 24 insertions(+) > If this code is going to be merged, there should also be a Documentation update to Documentation/kbuild/{kbuild.rst,modules.rst}. Thanks.
diff --git a/Makefile b/Makefile index 4bef6323c47d..5858708d357c 100644 --- a/Makefile +++ b/Makefile @@ -142,6 +142,7 @@ ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif +define kbuild_extmod_check_TEMPLATE $(if $(word 2, $(KBUILD_EXTMOD)), \ $(error building multiple external modules is not supported)) @@ -152,9 +153,25 @@ $(foreach x, % :, $(if $(findstring $x, $(KBUILD_EXTMOD)), \ ifneq ($(filter %/, $(KBUILD_EXTMOD)),) KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).) endif +endef +$(eval $(call kbuild_extmod_check_TEMPLATE)) export KBUILD_EXTMOD +# Use make M=src_dir MO=ko_dir or set the environment variables: +# KBUILD_EXTMOD_SRC, KBUILD_EXTMOD to specify separate directories of +# external module sources and build artifacts. +ifeq ("$(origin MO)", "command line") +ifeq (KBUILD_EXTMOD,) + $(error Ext module objects without module sources is not supported)) +endif +KBUILD_EXTMOD_SRC := $(KBUILD_EXTMOD) +KBUILD_EXTMOD := $(MO) +$(eval $(call kbuild_extmod_check_TEMPLATE)) +endif + +export KBUILD_EXTMOD_SRC + # backward compatibility KBUILD_EXTRA_WARN ?= $(KBUILD_ENABLE_EXTRA_GCC_CHECKS) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index baf86c0880b6..a293950e2e07 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -3,7 +3,14 @@ # Building # ========================================================================== +ifeq ($(KBUILD_EXTMOD_SRC),) src := $(obj) +else ifeq ($(KBUILD_EXTMOD),$(obj)) +override src := $(KBUILD_EXTMOD_SRC) +else +src_subdir := $(patsubst $(KBUILD_EXTMOD)/%,%,$(obj)) +override src := $(KBUILD_EXTMOD_SRC)/$(src_subdir) +endif PHONY := $(obj)/ $(obj)/:
The change allow to build external modules with nested makefiles. With current unofficial way(using "src" variable) it is posible to build external(out of tree) kernel module with separating source and build artifacts dirs but with nested makefiles it doesn't work properly. Build system trap to recursion inside makefiles, articafts output dir path grow with each iteration until exceed max path len and build failed Providing "MO" variable and using "override" directive with declaring "src" variable solve the problem Usage example: make -C KERNEL_SOURCE_TREE MO=BUILD_OUT_DIR M=EXT_MOD_SRC_DIR modules Cc: xe-linux-external@cisco.com Cc: Valerii Chernous <vchernou@cisco.com> Signed-off-by: Valerii Chernous <vchernou@cisco.com> --- Makefile | 17 +++++++++++++++++ scripts/Makefile.build | 7 +++++++ 2 files changed, 24 insertions(+)