kernel: Support kernel modules via kbuild
TARGET_EXTERNAL_KERNEL_MODULES variable is used for the list of modules,
same as the existing functionality, but is invoked if ':kbuild' is
appended to a module name
Existing external module build calls make in the module directory, which
is a standalone module build. The module makefile may chain to kbuild,
but that depends on the module. This addition invokes the kernel build
system, passing the module directory via the M= param, which is the
kernel standard for building out of tree modules.
Change-Id: I38a582952f79f7155cdbf8a5975cf23074bbdab0
diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 69f8780..ed1fe4f 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -282,6 +282,14 @@
$(PATH_OVERRIDE) $(KERNEL_MAKE_CMD) $(KERNEL_MAKE_FLAGS) -C $(TARGET_KERNEL_EXT_MODULE_ROOT)/$(1) M=$(2)/$(1) KERNEL_SRC=$(BUILD_TOP)/$(KERNEL_SRC) OUT_DIR=$(KERNEL_BUILD_OUT_PREFIX)$(KERNEL_OUT) O=$(KERNEL_BUILD_OUT_PREFIX)$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(3)
endef
+# Make an external module target using kbuild
+# $(1): module name
+# $(2): module root path relative to kernel source
+# $(2): target to build (eg. modules_install)
+define make-kbuild-module-target
+$(PATH_OVERRIDE) $(KERNEL_MAKE_CMD) $(KERNEL_MAKE_FLAGS) -C $(BUILD_TOP)/$(KERNEL_SRC) M=$(2)/$(1) O=$(KERNEL_BUILD_OUT_PREFIX)$(KERNEL_OUT) ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(3)
+endef
+
# Generate kernel .config from a given defconfig
# $(1): Output path (The value passed to O=)
# $(2): The defconfig to process (just the filename, no need for full path to file)
@@ -462,8 +470,8 @@
rpath=$$(python3 -c 'import os,sys;print(os.path.relpath(*(sys.argv[1:])))' $(TARGET_KERNEL_EXT_MODULE_ROOT) $(KERNEL_SRC)); \
$(foreach p, $(TARGET_KERNEL_EXT_MODULES),\
$$pwd; \
- $(call make-external-module-target,$(p),$$rpath,) || exit "$$?"; \
- $(call make-external-module-target,$(p),$$rpath,INSTALL_MOD_PATH=$(MODULES_INTERMEDIATES) INSTALL_MOD_STRIP=1 KERNEL_UAPI_HEADERS_DIR=$(KERNEL_OUT) modules_install)) || exit "$$?"; \
+ $(call $(if $(filter $(word 2,$(subst :, ,$(p))),kbuild),make-kbuild-module-target,make-external-module-target),$(word 1,$(subst :, ,$(p))),$$rpath,) || exit "$$?"; \
+ $(call $(if $(filter $(word 2,$(subst :, ,$(p))),kbuild),make-kbuild-module-target,make-external-module-target),$(word 1,$(subst :, ,$(p))),$$rpath,INSTALL_MOD_PATH=$(MODULES_INTERMEDIATES) INSTALL_MOD_STRIP=1 KERNEL_UAPI_HEADERS_DIR=$(KERNEL_OUT) modules_install)) || exit "$$?"; \
) \
kernel_release=$$(cat $(KERNEL_RELEASE)) \
kernel_modules_dir=$(MODULES_INTERMEDIATES)/lib/modules/$$kernel_release \