1 # SPDX-License-Identifier: GPL-2.0
3 # Makefile for the linux kernel.
6 ccflags-y := -fno-function-sections -fno-data-sections
8 obj-y := main.o version.o mounts.o
9 ifneq ($(CONFIG_BLK_DEV_INITRD),y)
10 obj-y += noinitramfs.o
12 obj-$(CONFIG_BLK_DEV_INITRD) += initramfs.o
14 obj-$(CONFIG_GENERIC_CALIBRATE_DELAY) += calibrate.o
18 mounts-y := do_mounts.o
19 mounts-$(CONFIG_BLK_DEV_RAM) += do_mounts_rd.o
20 mounts-$(CONFIG_BLK_DEV_INITRD) += do_mounts_initrd.o
26 smp-flag-$(CONFIG_SMP) := SMP
27 preempt-flag-$(CONFIG_PREEMPT_BUILD) := PREEMPT
28 preempt-flag-$(CONFIG_PREEMPT_DYNAMIC) := PREEMPT_DYNAMIC
29 preempt-flag-$(CONFIG_PREEMPT_RT) := PREEMPT_RT
31 build-version = $(or $(KBUILD_BUILD_VERSION), $(build-version-auto))
32 build-timestamp = $(or $(KBUILD_BUILD_TIMESTAMP), $(build-timestamp-auto))
34 # Maximum length of UTS_VERSION is 64 chars
35 filechk_uts_version = \
36 utsver=$$(echo '$(pound)'"$(build-version)" $(smp-flag-y) $(preempt-flag-y) "$(build-timestamp)" | cut -b -64); \
37 echo '$(pound)'define UTS_VERSION \""$${utsver}"\"
40 # Build version.c with temporary UTS_VERSION
43 $(obj)/utsversion-tmp.h: FORCE
44 $(call filechk,uts_version)
46 clean-files += utsversion-tmp.h
48 $(obj)/version.o: $(obj)/utsversion-tmp.h
49 CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
52 # Build version-timestamp.c with final UTS_VERSION
55 include/generated/utsversion.h: build-version-auto = $(shell $(srctree)/$(src)/build-version)
56 include/generated/utsversion.h: build-timestamp-auto = $(shell LC_ALL=C date)
57 include/generated/utsversion.h: FORCE
58 $(call filechk,uts_version)
60 $(obj)/version-timestamp.o: include/generated/utsversion.h
61 CFLAGS_version-timestamp.o := -include include/generated/utsversion.h