linux-kernel-module-cheat/kernel_modules/Makefile

# Trying to do:
# $(MAKE) -C '$(LINUX_DIR)' M='$(M)' hello.ko hello2.ko
# to restrict which modules are built leads to failures
# when doing parallel builds. The only solution I could find
# was to let the host select obj-m itself.
obj-m += $(OBJECT_FILES)
ccflags-y := \
  -DDEBUG \
  -ggdb3 \
  -std=gnu99 \
  -Werror \
  -Wframe-larger-than=1000000000 \
  -Wno-declaration-after-statement \
  $(CCFLAGS)

ifeq ($(ARCH),x86)
	# https://cirosantilli.com/linux-kernel-module-cheat#floating-point-in-kernel-modules
	CFLAGS_REMOVE_float.o += -mno-sse -mno-sse2
endif

.PHONY: all

all:
	$(MAKE) -C '$(LINUX_DIR)' M='$(M)'