# SPDX-License-Identifier: GPL-2.0-only
#
# Copyright (C) 2006-2020 OpenWrt.org

ifdef CONFIG_STRIP_KERNEL_EXPORTS
  KERNEL_MAKEOPTS_IMAGE += \
	EXTRA_LDSFLAGS="-I$(KERNEL_BUILD_DIR) -include symtab.h"
endif

INITRAMFS_EXTRA_FILES ?= $(GENERIC_PLATFORM_DIR)/image/initramfs-base-files.txt

export HOST_EXTRACFLAGS=-I$(STAGING_DIR_HOST)/include

# defined in quilt.mk
Kernel/Patch:=$(Kernel/Patch/Default)

ifneq (,$(findstring .xz,$(LINUX_SOURCE)))
  LINUX_CAT:=xzcat
else
  LINUX_CAT:=$(STAGING_DIR_HOST)/bin/libdeflate-gzip -dc
endif

ifeq ($(strip $(CONFIG_EXTERNAL_KERNEL_TREE)),"")
  ifeq ($(strip $(CONFIG_KERNEL_GIT_CLONE_URI)),"")
    define Kernel/Prepare/Default
	$(LINUX_CAT) $(DL_DIR)/$(LINUX_SOURCE) | $(TAR) -C $(KERNEL_BUILD_DIR) $(TAR_OPTIONS)
	$(Kernel/Patch)
	$(if $(QUILT),touch $(LINUX_DIR)/.quilt_used)
    endef
  else
    define Kernel/Prepare/Default
	$(LINUX_CAT) $(DL_DIR)/$(LINUX_SOURCE) | $(TAR) -C $(KERNEL_BUILD_DIR) $(TAR_OPTIONS)
    endef
  endif
else
  define Kernel/Prepare/Default
	mkdir -p $(KERNEL_BUILD_DIR)
	if [ -d $(LINUX_DIR) ]; then \
		rmdir $(LINUX_DIR); \
	fi
	ln -s $(CONFIG_EXTERNAL_KERNEL_TREE) $(LINUX_DIR)
	if [ -d $(LINUX_DIR)/user_headers ]; then \
		rm -rf $(LINUX_DIR)/user_headers; \
	fi
  endef
endif

ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),y)
  ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),y)
    define Kernel/SetInitramfs/PreConfigure
	grep -v -e CONFIG_BLK_DEV_INITRD $(2)/.config.old > $(2)/.config
	echo 'CONFIG_BLK_DEV_INITRD=y' >> $(2)/.config
	echo 'CONFIG_INITRAMFS_SOURCE=""' >> $(2)/.config
    endef
  else
  ifeq ($(strip $(CONFIG_EXTERNAL_CPIO)),"")
    define Kernel/SetInitramfs/PreConfigure
	grep -v -e INITRAMFS -e CONFIG_RD_ -e CONFIG_BLK_DEV_INITRD $(2)/.config.old > $(2)/.config
	echo 'CONFIG_BLK_DEV_INITRD=y' >> $(2)/.config
	echo 'CONFIG_INITRAMFS_SOURCE="$(strip $(1) $(INITRAMFS_EXTRA_FILES))"' >> $(2)/.config
    endef
  else
    define Kernel/SetInitramfs/PreConfigure
	grep -v INITRAMFS $(2)/.config.old > $(2)/.config
	echo 'CONFIG_INITRAMFS_SOURCE="$(call qstrip,$(CONFIG_EXTERNAL_CPIO))"' >> $(2)/.config
    endef
  endif
endif

  define Kernel/SetInitramfs
	rm -f $(2)/.config.prev
	mv $(2)/.config $(2)/.config.old
	$(call Kernel/SetInitramfs/PreConfigure,$(1),$(2))
	echo "# CONFIG_INITRAMFS_PRESERVE_MTIME is not set" >> $(2)/.config
  ifneq ($(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),y)
	echo 'CONFIG_INITRAMFS_ROOT_UID=$(shell id -u)' >> $(2)/.config
	echo 'CONFIG_INITRAMFS_ROOT_GID=$(shell id -g)' >> $(2)/.config
	echo "$(if $(CONFIG_TARGET_INITRAMFS_FORCE),CONFIG_INITRAMFS_FORCE=y,# CONFIG_INITRAMFS_FORCE is not set)" >> $(2)/.config
  else
	echo "# CONFIG_INITRAMFS_FORCE is not set" >> $(2)/.config
  endif
	echo "$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_NONE),CONFIG_INITRAMFS_COMPRESSION_NONE=y,# CONFIG_INITRAMFS_COMPRESSION_NONE is not set)" >> $(2)/.config
	$(foreach ALGO,GZIP BZIP2 LZMA LZO XZ LZ4 ZSTD, \
		$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_$(ALGO)),\
			echo -e "CONFIG_INITRAMFS_COMPRESSION_$(ALGO)=y\nCONFIG_RD_$(ALGO)=y" >> $(2)/.config;,\
			echo -e "# CONFIG_INITRAMFS_COMPRESSION_$(ALGO) is not set\n# CONFIG_RD_$(ALGO) is not set" >> $(2)/.config;))
  endef
else
endif

define Kernel/SetNoInitramfs
	mv $(LINUX_DIR)/.config.set $(LINUX_DIR)/.config.old
	grep -v INITRAMFS $(LINUX_DIR)/.config.old > $(LINUX_DIR)/.config.set
	echo 'CONFIG_INITRAMFS_SOURCE=""' >> $(LINUX_DIR)/.config.set
	echo '# CONFIG_INITRAMFS_FORCE is not set' >> $(LINUX_DIR)/.config.set
	echo "# CONFIG_INITRAMFS_PRESERVE_MTIME is not set" >> $(LINUX_DIR)/.config.set
endef

define Kernel/Configure/Default
	rm -f $(LINUX_DIR)/localversion
	$(LINUX_CONF_CMD) > $(LINUX_DIR)/.config.target
# copy CONFIG_KERNEL_* settings over to .config.target
	awk '/^(#[[:space:]]+)?CONFIG_KERNEL/{sub("CONFIG_KERNEL_","CONFIG_");print}' $(TOPDIR)/.config >> $(LINUX_DIR)/.config.target
	echo "# CONFIG_KALLSYMS_EXTRA_PASS is not set" >> $(LINUX_DIR)/.config.target
	echo "# CONFIG_KALLSYMS_ALL is not set" >> $(LINUX_DIR)/.config.target
	echo "CONFIG_KALLSYMS_UNCOMPRESSED=y" >> $(LINUX_DIR)/.config.target
	$(SCRIPT_DIR)/package-metadata.pl kconfig $(TMP_DIR)/.packageinfo $(TOPDIR)/.config $(KERNEL_PATCHVER) > $(LINUX_DIR)/.config.override
	$(SCRIPT_DIR)/kconfig.pl 'm+' '+' $(LINUX_DIR)/.config.target /dev/null $(LINUX_DIR)/.config.override > $(LINUX_DIR)/.config.set
	$(call Kernel/SetNoInitramfs)
	rm -rf $(KERNEL_BUILD_DIR)/modules
	cmp -s $(LINUX_DIR)/.config.set $(LINUX_DIR)/.config.prev || { \
		cp $(LINUX_DIR)/.config.set $(LINUX_DIR)/.config; \
		cp $(LINUX_DIR)/.config.set $(LINUX_DIR)/.config.prev; \
	}
	$(_SINGLE) [ -d $(LINUX_DIR)/user_headers ] || $(KERNEL_MAKE) $(if $(findstring uml,$(BOARD)),ARCH=$(ARCH)) INSTALL_HDR_PATH=$(LINUX_DIR)/user_headers headers_install
	grep '=[ym]' $(LINUX_DIR)/.config.set | LC_ALL=C sort | $(MKHASH) md5 > $(LINUX_DIR)/.vermagic
endef

define Kernel/Configure/Initramfs
	$(call Kernel/SetInitramfs,$(1),$(2))
endef

define Kernel/CompileModules/Default
	rm -f $(LINUX_DIR)/vmlinux $(LINUX_DIR)/System.map
	+$(KERNEL_MAKE) $(if $(KERNELNAME),$(KERNELNAME),all) modules
	# If .config did not change, use the previous timestamp to avoid package rebuilds
	cmp -s $(LINUX_DIR)/.config $(LINUX_DIR)/.config.modules.save && \
		mv $(LINUX_DIR)/.config.modules.save $(LINUX_DIR)/.config; \
	$(CP) $(LINUX_DIR)/.config $(LINUX_DIR)/.config.modules.save
endef

OBJCOPY_STRIP = -R .reginfo -R .notes -R .note -R .comment -R .mdebug -R .note.gnu.build-id

# AMD64 shares the location with x86
ifeq ($(LINUX_KARCH),x86_64)
IMAGES_DIR:=../../x86/boot
endif

# $1: image suffix
# $2: Per Device Rootfs ID
define Kernel/CopyImage
	cmp -s $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2) || { \
		$(KERNEL_CROSS)objcopy -O binary $(OBJCOPY_STRIP) -S $(LINUX_DIR)/vmlinux $(LINUX_KERNEL)$(1)$(2); \
		$(KERNEL_CROSS)objcopy $(OBJCOPY_STRIP) -S $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).elf$(2); \
		$(CP) $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2); \
		$(foreach k, \
			$(if $(KERNEL_IMAGES),$(KERNEL_IMAGES),$(filter-out vmlinux dtbs,$(KERNELNAME))), \
			$(CP) $(LINUX_DIR)/arch/$(LINUX_KARCH)/boot/$(IMAGES_DIR)/$(k) $(KERNEL_BUILD_DIR)/$(k)$(1)$(2); \
		) \
	}
endef

define Kernel/CompileImage/Default
	rm -f $(TARGET_DIR)/init
	+$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all)
	$(call Kernel/CopyImage)
endef

define Kernel/PrepareConfigPerRootfs
	[ ! -d "$(1)" ] || rm -rf $(1)
	mkdir $(1)

	$(CP) $(LINUX_DIR)/.config $(1)
endef

ifneq ($(CONFIG_TARGET_ROOTFS_INITRAMFS),)
# $1: Custom TARGET_DIR. If omitted TARGET_DIR is used.
# $2: If defined Generate Per Rootfs Kernel Directory and use it
# For Separate Initramf with $2 declared, skip kernel compile, it has
# already been done previously on generic image build
define Kernel/CompileImage/Initramfs
	$(if $(2),$(call Kernel/PrepareConfigPerRootfs,$(LINUX_DIR)$(2)))
	$(call Kernel/Configure/Initramfs,$(if $(1),$(1),$(TARGET_DIR)),$(LINUX_DIR)$(2))
	$(CP) $(GENERIC_PLATFORM_DIR)/other-files/init $(if $(1),$(1),$(TARGET_DIR))/init
	$(if $(SOURCE_DATE_EPOCH),touch -hcd "@$(SOURCE_DATE_EPOCH)" $(if $(1),$(1),$(TARGET_DIR)) $(if $(1),$(1),$(TARGET_DIR))/init)
ifeq ($(CONFIG_TARGET_ROOTFS_INITRAMFS_SEPARATE),y)
ifneq ($(call qstrip,$(CONFIG_EXTERNAL_CPIO)),)
	$(CP) $(CONFIG_EXTERNAL_CPIO) $(KERNEL_BUILD_DIR)/initrd.cpio$(2)
else
	( cd $(if $(1),$(1),$(TARGET_DIR)); find . | LC_ALL=C sort | $(STAGING_DIR_HOST)/bin/cpio --reproducible -o -H newc -R 0:0 > $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio )
endif
	$(if $(SOURCE_DATE_EPOCH),touch -hcd "@$(SOURCE_DATE_EPOCH)" $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_BZIP2),$(STAGING_DIR_HOST)/bin/bzip2 -9 -c < $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio > $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio.bzip2)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_GZIP),$(STAGING_DIR_HOST)/bin/libdeflate-gzip -n -f -S .gzip -12 $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZ4),$(STAGING_DIR_HOST)/bin/lz4c -l -c1 -fz --favor-decSpeed $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZMA),$(STAGING_DIR_HOST)/bin/lzma e -lc1 -lp2 -pb2 $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio.lzma)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_LZO),$(STAGING_DIR_HOST)/bin/lzop -9 -f $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_XZ),$(STAGING_DIR_HOST)/bin/xz -T$(if $(filter 1,$(NPROC)),2,0) -9 -fz --check=crc32 $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD),$(STAGING_DIR_HOST)/bin/zstd -T0 -f -o $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio.zstd $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio)
	$(if $(2),,$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all))
	$(call Kernel/CopyImage,-initramfs,$(2))
else
	+$(call locked,$(if $(2),$(CP) $(LINUX_DIR)$(2)/.config* $(LINUX_DIR) && touch $(LINUX_DIR)/.config && )\
		rm -rf $(LINUX_DIR)/usr/initramfs_data.cpio* $(LINUX_DIR)/.config.prev && \
		$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all) && \
		{ $(call Kernel/CopyImage,-initramfs,$(2)) },gen-initramfs)
endif
endef
else
define Kernel/CompileImage/Initramfs
endef
endif

define Kernel/Clean/Default
	rm -f $(KERNEL_BUILD_DIR)/linux-$(LINUX_VERSION)/.configured
	rm -f $(LINUX_KERNEL)
	$(_SINGLE)$(MAKE) -C $(KERNEL_BUILD_DIR)/linux-$(LINUX_VERSION) clean
endef