kernel.mk - device/generic/brillo - Git at Google

 #
 # Copyright 2015 The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #

 # Targets for builing kernels
 #
 # The following must be set before including this file:
 # TARGET_KERNEL_SRC must be set the base of a kernel tree.
 # TARGET_KERNEL_DEFCONFIG must name a base kernel config.
 # TARGET_KERNEL_ARCH must be set to match kernel arch.
 #
 # The following maybe set:
 # TARGET_KERNEL_CROSS_COMPILE_PREFIX to override toolchain.
 # TARGET_KERNEL_CONFIGS to specify a set of additional kernel configs.
 # TARGET_KERNEL_DTB to define a DTB to build.
 # TARGET_KERNEL_DTB_APPEND to append the built DTB to the kernel.


 # Brillo does not support prebuilt kernels.
 ifneq ($(TARGET_PREBUILT_KERNEL),)
 $(error TARGET_PREBUILT_KERNEL defined but Brillo kernels build from source)
 endif

 ifeq ($(TARGET_KERNEL_SRC),)
 $(error TARGET_KERNEL_SRC not defined)
 endif

 ifeq ($(TARGET_KERNEL_DEFCONFIG),)
 $(error TARGET_KERNEL_DEFCONFIG not defined)
 endif

 ifeq ($(TARGET_KERNEL_ARCH),)
 $(error TARGET_KERNEL_ARCH not defined)
 endif

 # This is optional, but we'd like to use it as a dependency.
 ifndef TARGET_KERNEL_CONFIGS
 TARGET_KERNEL_CONFIGS := /dev/null
 endif

 # Check target arch.
 KERNEL_TOOLCHAIN_ABS := $(realpath $(TARGET_TOOLCHAIN_ROOT)/bin)
 TARGET_KERNEL_ARCH := $(strip $(TARGET_KERNEL_ARCH))
 KERNEL_ARCH := $(TARGET_KERNEL_ARCH)
 KERNEL_CC_WRAPPER := $(CC_WRAPPER)
 KERNEL_AFLAGS :=

 ifeq ($(TARGET_KERNEL_ARCH), arm)
 KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/arm-linux-androidkernel-
 KERNEL_SRC_ARCH := arm
 KERNEL_CFLAGS :=
 ifdef TARGET_KERNEL_DTB
 KERNEL_NAME := zImage
 else
 # If TARGET_KERNEL_DTB is not defined, the source tree already has logic
 # built into it to produce a merged kernel/DTB image.
 KERNEL_NAME := zImage-dtb
 endif
 else ifeq ($(TARGET_KERNEL_ARCH), arm64)
 KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/aarch64-linux-androidkernel-
 KERNEL_SRC_ARCH := arm64
 KERNEL_CFLAGS :=
 KERNEL_NAME := Image.gz
 else ifeq ($(TARGET_KERNEL_ARCH), i386)
 KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/x86_64-linux-androidkernel-
 KERNEL_SRC_ARCH := x86
 KERNEL_CFLAGS := -mstack-protector-guard=tls
 KERNEL_NAME := bzImage
 else ifeq ($(TARGET_KERNEL_ARCH), x86_64)
 KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/x86_64-linux-androidkernel-
 KERNEL_SRC_ARCH := x86
 KERNEL_CFLAGS := -mstack-protector-guard=tls
 KERNEL_NAME := bzImage
 else ifeq ($(TARGET_KERNEL_ARCH), mips)
 KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/mips64el-linux-androidkernel-
 KERNEL_SRC_ARCH := mips
 KERNEL_CFLAGS :=
 KERNEL_NAME := compressed/vmlinux.bin
 # TODO(b/27679097): Re-enable after Goma issues are fixed.
 KERNEL_CC_WRAPPER :=
 else
 $(error kernel arch not supported at present)
 endif

 # Allow caller to override toolchain.
 TARGET_KERNEL_CROSS_COMPILE_PREFIX := $(strip $(TARGET_KERNEL_CROSS_COMPILE_PREFIX))
 ifneq ($(TARGET_KERNEL_CROSS_COMPILE_PREFIX),)
 KERNEL_CROSS_COMPILE := $(TARGET_KERNEL_CROSS_COMPILE_PREFIX)
 endif

 # Use ccache if requested by USE_CCACHE variable
 KERNEL_CROSS_COMPILE_WRAPPER := $(realpath $(KERNEL_CC_WRAPPER)) $(KERNEL_CROSS_COMPILE)

 KERNEL_GCC_NOANDROID_CHK := $(shell (echo "int main() {return 0;}" | $(KERNEL_CROSS_COMPILE)gcc -E -mno-android - > /dev/null 2>&1 ; echo $$?))
 ifeq ($(strip $(KERNEL_GCC_NOANDROID_CHK)),0)
 KERNEL_CFLAGS += -mno-android
 KERNEL_AFLAGS += -mno-android
 endif

 # Set the output for the kernel build products.
 KERNEL_OUT := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ

 # The kernel configs, in precedence order.
 KERNEL_CONFIG_DEFAULT := $(KERNEL_OUT)/.config.default
 KERNEL_CONFIG_RECOMMENDED := $(KERNEL_OUT)/.config.recommended
 KERNEL_CONFIG_PRODUCT := $(KERNEL_OUT)/.config.product
 KERNEL_CONFIG_REQUIRED := $(KERNEL_OUT)/.config.required
 KERNEL_CONFIG := $(KERNEL_OUT)/.config

 KERNEL_BIN := $(KERNEL_OUT)/arch/$(KERNEL_SRC_ARCH)/boot/$(KERNEL_NAME)

 # Figure out which kernel version is being built (disregard -stable version).
 KERNEL_VERSION := $(shell $(MAKE) --no-print-directory -C $(TARGET_KERNEL_SRC) -s SUBLEVEL="" kernelversion)

 KERNEL_CONFIGS_DIR := device/generic/brillo/kconfig
 KERNEL_CONFIGS_COMMON := $(KERNEL_CONFIGS_DIR)/common.config
 KERNEL_CONFIGS_ARCH := $(KERNEL_CONFIGS_DIR)/$(KERNEL_ARCH).config
 KERNEL_CONFIGS_VER := $(KERNEL_CONFIGS_DIR)/$(KERNEL_VERSION)/common.config
 KERNEL_CONFIGS_VER_ARCH := $(KERNEL_CONFIGS_DIR)/$(KERNEL_VERSION)/$(KERNEL_ARCH).config
 KERNEL_CONFIGS_RECOMMENDED := $(KERNEL_CONFIGS_DIR)/recommended.config

 KERNEL_MERGE_CONFIG := device/generic/brillo/mergeconfig.sh
 KERNEL_HEADERS_INSTALL := $(KERNEL_OUT)/usr

 $(KERNEL_OUT):
 	mkdir -p $(KERNEL_OUT)

 $(KERNEL_CONFIG_DEFAULT): $(TARGET_KERNEL_SRC)/arch/$(KERNEL_SRC_ARCH)/configs/$(TARGET_KERNEL_DEFCONFIG) | $(KERNEL_OUT)
 	$(hide) cat $< > $@

 $(KERNEL_CONFIG_RECOMMENDED): $(KERNEL_CONFIGS_RECOMMENDED) | $(KERNEL_OUT)
 	$(hide) cat $< > $@

 $(KERNEL_CONFIG_PRODUCT): $(TARGET_KERNEL_CONFIGS) | $(KERNEL_OUT)
 	$(hide) cat $< > $@

 # Merge the required kernel config elements.
 $(KERNEL_CONFIG_REQUIRED): $(KERNEL_CONFIGS_COMMON) $(KERNEL_CONFIGS_ARCH) \
 			   $(KERNEL_CONFIGS_VER) $(KERNEL_CONFIGS_VER_ARCH) \
 			   | $(KERNEL_OUT)
 	$(hide) cat $(filter-out $(KERNEL_OUT),$^) > $@

 # Merge the final target kernel config.
 $(KERNEL_CONFIG): $(KERNEL_CONFIG_DEFAULT) $(KERNEL_CONFIG_RECOMMENDED) \
 		  $(KERNEL_CONFIG_PRODUCT) $(KERNEL_CONFIG_REQUIRED) \
 		  | $(KERNEL_OUT)
 	$(hide) echo Merging kernel config
 	$(KERNEL_MERGE_CONFIG) $(TARGET_KERNEL_SRC) $(realpath $(KERNEL_OUT)) \
 		$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) \
 		$(realpath $(KERNEL_CONFIG_DEFAULT)) \
 		$(realpath $(KERNEL_CONFIG_RECOMMENDED)) \
 		$(realpath $(KERNEL_CONFIG_PRODUCT)) \
 		$(realpath $(KERNEL_CONFIG_REQUIRED))

 # Disable CCACHE_DIRECT so that header location changes are noticed.
 define build_kernel
 	CCACHE_NODIRECT="true" $(MAKE) -C $(TARGET_KERNEL_SRC) \
 		O=$(realpath $(KERNEL_OUT)) \
 		ARCH=$(KERNEL_ARCH) \
 		CROSS_COMPILE="$(KERNEL_CROSS_COMPILE_WRAPPER)" \
 		KCFLAGS="$(KERNEL_CFLAGS)" \
 		KAFLAGS="$(KERNEL_AFLAGS)" \
 		INSTALL_MOD_PATH=$(realpath $(TARGET_OUT)) \
 		$(1)
 endef

 $(KERNEL_BIN): $(KERNEL_CONFIG) | $(KERNEL_OUT)
 	$(hide) echo "Building $(KERNEL_ARCH) $(KERNEL_VERSION) kernel ..."
 	$(hide) rm -rf $(KERNEL_OUT)/arch/$(KERNEL_ARCH)/boot/dts
 	$(hide) rm -rf $(PRODUCT_OUT)/kernel.dtb $(PRODUCT_OUT)/kernel-and-dtb
 	$(call build_kernel,all)
 	if grep -q ^CONFIG_MODULES=y $(KERNEL_CONFIG) ; then \
 		$(call build_kernel,modules_install) ; \
 	fi

 $(KERNEL_HEADERS_INSTALL): $(KERNEL_BIN)
 	$(hide) echo "Installing kernel headers ..."
 	$(call build_kernel,headers_install)

 # If the kernel generates VDSO files, generate breakpad symbol files for them.
 # VDSO libraries are mapped as linux-gate.so, so rename the symbol file to
 # match as well as the filename in the first line of the .sym file.
 .PHONY: $(KERNEL_BIN).vdso
 $(KERNEL_BIN).vdso: $(KERNEL_BIN)
 ifeq ($(BREAKPAD_GENERATE_SYMBOLS),true)
 	$(hide) echo "BREAKPAD: Generating kernel VDSO symbol files."
 	$(hide) set -e; \
 	for sofile in `cd $(KERNEL_OUT) && find . -type f -name '*.so'`; do \
 		mkdir -p $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}; \
 		$(BREAKPAD_DUMP_SYMS) -c $(KERNEL_OUT)/$${sofile} > $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym; \
 		sed -i.tmp "1s/`basename "$${sofile}"`/linux-gate.so/" $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym; \
 		rm $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym.tmp; \
 	done
 endif

 # Merges all TARGET_KERNEL_DTB files together into a single kernel.dtb.
 KERNEL_DTB := $(addprefix $(KERNEL_OUT)/arch/$(KERNEL_SRC_ARCH)/boot/dts/, $(TARGET_KERNEL_DTB))
 $(PRODUCT_OUT)/kernel.dtb: $(KERNEL_BIN)
 	$(hide) cat $(KERNEL_DTB) > $@

 # Produces a merged kernel and kernel.dtb file.
 $(PRODUCT_OUT)/kernel-and-dtb: $(KERNEL_BIN) $(PRODUCT_OUT)/kernel.dtb
 	$(hide) cat $^ > $@

 # The list of dependencies for the final kernel.
 KERNEL_DEPS := $(KERNEL_BIN).vdso $(KERNEL_HEADERS_INSTALL)
 ifdef TARGET_KERNEL_DTB
 # If we need the DTB, include it in the build list.
 KERNEL_DEPS += $(PRODUCT_OUT)/kernel.dtb
 endif

 # The final kernel image is either the raw kernel binary or merged kernel+dtb.
 ifdef TARGET_KERNEL_DTB_APPEND
 KERNEL_IMAGE := $(PRODUCT_OUT)/kernel-and-dtb
 else
 KERNEL_IMAGE := $(KERNEL_BIN)
 endif

 # Produces the actual kernel image!
 $(PRODUCT_OUT)/kernel: $(KERNEL_IMAGE) $(KERNEL_DEPS) | $(ACP)
 	$(ACP) -fp $< $@
	#
	# Copyright 2015 The Android Open Source Project
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	#

	# Targets for builing kernels
	#
	# The following must be set before including this file:
	# TARGET_KERNEL_SRC must be set the base of a kernel tree.
	# TARGET_KERNEL_DEFCONFIG must name a base kernel config.
	# TARGET_KERNEL_ARCH must be set to match kernel arch.
	#
	# The following maybe set:
	# TARGET_KERNEL_CROSS_COMPILE_PREFIX to override toolchain.
	# TARGET_KERNEL_CONFIGS to specify a set of additional kernel configs.
	# TARGET_KERNEL_DTB to define a DTB to build.
	# TARGET_KERNEL_DTB_APPEND to append the built DTB to the kernel.


	# Brillo does not support prebuilt kernels.
	ifneq ($(TARGET_PREBUILT_KERNEL),)
	$(error TARGET_PREBUILT_KERNEL defined but Brillo kernels build from source)
	endif

	ifeq ($(TARGET_KERNEL_SRC),)
	$(error TARGET_KERNEL_SRC not defined)
	endif

	ifeq ($(TARGET_KERNEL_DEFCONFIG),)
	$(error TARGET_KERNEL_DEFCONFIG not defined)
	endif

	ifeq ($(TARGET_KERNEL_ARCH),)
	$(error TARGET_KERNEL_ARCH not defined)
	endif

	# This is optional, but we'd like to use it as a dependency.
	ifndef TARGET_KERNEL_CONFIGS
	TARGET_KERNEL_CONFIGS := /dev/null
	endif

	# Check target arch.
	KERNEL_TOOLCHAIN_ABS := $(realpath $(TARGET_TOOLCHAIN_ROOT)/bin)
	TARGET_KERNEL_ARCH := $(strip $(TARGET_KERNEL_ARCH))
	KERNEL_ARCH := $(TARGET_KERNEL_ARCH)
	KERNEL_CC_WRAPPER := $(CC_WRAPPER)
	KERNEL_AFLAGS :=

	ifeq ($(TARGET_KERNEL_ARCH), arm)
	KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/arm-linux-androidkernel-
	KERNEL_SRC_ARCH := arm
	KERNEL_CFLAGS :=
	ifdef TARGET_KERNEL_DTB
	KERNEL_NAME := zImage
	else
	# If TARGET_KERNEL_DTB is not defined, the source tree already has logic
	# built into it to produce a merged kernel/DTB image.
	KERNEL_NAME := zImage-dtb
	endif
	else ifeq ($(TARGET_KERNEL_ARCH), arm64)
	KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/aarch64-linux-androidkernel-
	KERNEL_SRC_ARCH := arm64
	KERNEL_CFLAGS :=
	KERNEL_NAME := Image.gz
	else ifeq ($(TARGET_KERNEL_ARCH), i386)
	KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/x86_64-linux-androidkernel-
	KERNEL_SRC_ARCH := x86
	KERNEL_CFLAGS := -mstack-protector-guard=tls
	KERNEL_NAME := bzImage
	else ifeq ($(TARGET_KERNEL_ARCH), x86_64)
	KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/x86_64-linux-androidkernel-
	KERNEL_SRC_ARCH := x86
	KERNEL_CFLAGS := -mstack-protector-guard=tls
	KERNEL_NAME := bzImage
	else ifeq ($(TARGET_KERNEL_ARCH), mips)
	KERNEL_CROSS_COMPILE := $(KERNEL_TOOLCHAIN_ABS)/mips64el-linux-androidkernel-
	KERNEL_SRC_ARCH := mips
	KERNEL_CFLAGS :=
	KERNEL_NAME := compressed/vmlinux.bin
	# TODO(b/27679097): Re-enable after Goma issues are fixed.
	KERNEL_CC_WRAPPER :=
	else
	$(error kernel arch not supported at present)
	endif

	# Allow caller to override toolchain.
	TARGET_KERNEL_CROSS_COMPILE_PREFIX := $(strip $(TARGET_KERNEL_CROSS_COMPILE_PREFIX))
	ifneq ($(TARGET_KERNEL_CROSS_COMPILE_PREFIX),)
	KERNEL_CROSS_COMPILE := $(TARGET_KERNEL_CROSS_COMPILE_PREFIX)
	endif

	# Use ccache if requested by USE_CCACHE variable
	KERNEL_CROSS_COMPILE_WRAPPER := $(realpath $(KERNEL_CC_WRAPPER)) $(KERNEL_CROSS_COMPILE)

	KERNEL_GCC_NOANDROID_CHK := $(shell (echo "int main() {return 0;}" \| $(KERNEL_CROSS_COMPILE)gcc -E -mno-android - > /dev/null 2>&1 ; echo $$?))
	ifeq ($(strip $(KERNEL_GCC_NOANDROID_CHK)),0)
	KERNEL_CFLAGS += -mno-android
	KERNEL_AFLAGS += -mno-android
	endif

	# Set the output for the kernel build products.
	KERNEL_OUT := $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ

	# The kernel configs, in precedence order.
	KERNEL_CONFIG_DEFAULT := $(KERNEL_OUT)/.config.default
	KERNEL_CONFIG_RECOMMENDED := $(KERNEL_OUT)/.config.recommended
	KERNEL_CONFIG_PRODUCT := $(KERNEL_OUT)/.config.product
	KERNEL_CONFIG_REQUIRED := $(KERNEL_OUT)/.config.required
	KERNEL_CONFIG := $(KERNEL_OUT)/.config

	KERNEL_BIN := $(KERNEL_OUT)/arch/$(KERNEL_SRC_ARCH)/boot/$(KERNEL_NAME)

	# Figure out which kernel version is being built (disregard -stable version).
	KERNEL_VERSION := $(shell $(MAKE) --no-print-directory -C $(TARGET_KERNEL_SRC) -s SUBLEVEL="" kernelversion)

	KERNEL_CONFIGS_DIR := device/generic/brillo/kconfig
	KERNEL_CONFIGS_COMMON := $(KERNEL_CONFIGS_DIR)/common.config
	KERNEL_CONFIGS_ARCH := $(KERNEL_CONFIGS_DIR)/$(KERNEL_ARCH).config
	KERNEL_CONFIGS_VER := $(KERNEL_CONFIGS_DIR)/$(KERNEL_VERSION)/common.config
	KERNEL_CONFIGS_VER_ARCH := $(KERNEL_CONFIGS_DIR)/$(KERNEL_VERSION)/$(KERNEL_ARCH).config
	KERNEL_CONFIGS_RECOMMENDED := $(KERNEL_CONFIGS_DIR)/recommended.config

	KERNEL_MERGE_CONFIG := device/generic/brillo/mergeconfig.sh
	KERNEL_HEADERS_INSTALL := $(KERNEL_OUT)/usr

	$(KERNEL_OUT):
	mkdir -p $(KERNEL_OUT)

	$(KERNEL_CONFIG_DEFAULT): $(TARGET_KERNEL_SRC)/arch/$(KERNEL_SRC_ARCH)/configs/$(TARGET_KERNEL_DEFCONFIG) \| $(KERNEL_OUT)
	$(hide) cat $< > $@

	$(KERNEL_CONFIG_RECOMMENDED): $(KERNEL_CONFIGS_RECOMMENDED) \| $(KERNEL_OUT)
	$(hide) cat $< > $@

	$(KERNEL_CONFIG_PRODUCT): $(TARGET_KERNEL_CONFIGS) \| $(KERNEL_OUT)
	$(hide) cat $< > $@

	# Merge the required kernel config elements.
	$(KERNEL_CONFIG_REQUIRED): $(KERNEL_CONFIGS_COMMON) $(KERNEL_CONFIGS_ARCH) \
	$(KERNEL_CONFIGS_VER) $(KERNEL_CONFIGS_VER_ARCH) \
	\| $(KERNEL_OUT)
	$(hide) cat $(filter-out $(KERNEL_OUT),$^) > $@

	# Merge the final target kernel config.
	$(KERNEL_CONFIG): $(KERNEL_CONFIG_DEFAULT) $(KERNEL_CONFIG_RECOMMENDED) \
	$(KERNEL_CONFIG_PRODUCT) $(KERNEL_CONFIG_REQUIRED) \
	\| $(KERNEL_OUT)
	$(hide) echo Merging kernel config
	$(KERNEL_MERGE_CONFIG) $(TARGET_KERNEL_SRC) $(realpath $(KERNEL_OUT)) \
	$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) \
	$(realpath $(KERNEL_CONFIG_DEFAULT)) \
	$(realpath $(KERNEL_CONFIG_RECOMMENDED)) \
	$(realpath $(KERNEL_CONFIG_PRODUCT)) \
	$(realpath $(KERNEL_CONFIG_REQUIRED))

	# Disable CCACHE_DIRECT so that header location changes are noticed.
	define build_kernel
	CCACHE_NODIRECT="true" $(MAKE) -C $(TARGET_KERNEL_SRC) \
	O=$(realpath $(KERNEL_OUT)) \
	ARCH=$(KERNEL_ARCH) \
	CROSS_COMPILE="$(KERNEL_CROSS_COMPILE_WRAPPER)" \
	KCFLAGS="$(KERNEL_CFLAGS)" \
	KAFLAGS="$(KERNEL_AFLAGS)" \
	INSTALL_MOD_PATH=$(realpath $(TARGET_OUT)) \
	$(1)
	endef

	$(KERNEL_BIN): $(KERNEL_CONFIG) \| $(KERNEL_OUT)
	$(hide) echo "Building $(KERNEL_ARCH) $(KERNEL_VERSION) kernel ..."
	$(hide) rm -rf $(KERNEL_OUT)/arch/$(KERNEL_ARCH)/boot/dts
	$(hide) rm -rf $(PRODUCT_OUT)/kernel.dtb $(PRODUCT_OUT)/kernel-and-dtb
	$(call build_kernel,all)
	if grep -q ^CONFIG_MODULES=y $(KERNEL_CONFIG) ; then \
	$(call build_kernel,modules_install) ; \
	fi

	$(KERNEL_HEADERS_INSTALL): $(KERNEL_BIN)
	$(hide) echo "Installing kernel headers ..."
	$(call build_kernel,headers_install)

	# If the kernel generates VDSO files, generate breakpad symbol files for them.
	# VDSO libraries are mapped as linux-gate.so, so rename the symbol file to
	# match as well as the filename in the first line of the .sym file.
	.PHONY: $(KERNEL_BIN).vdso
	$(KERNEL_BIN).vdso: $(KERNEL_BIN)
	ifeq ($(BREAKPAD_GENERATE_SYMBOLS),true)
	$(hide) echo "BREAKPAD: Generating kernel VDSO symbol files."
	$(hide) set -e; \
	for sofile in `cd $(KERNEL_OUT) && find . -type f -name '*.so'`; do \
	mkdir -p $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}; \
	$(BREAKPAD_DUMP_SYMS) -c $(KERNEL_OUT)/$${sofile} > $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym; \
	sed -i.tmp "1s/`basename "$${sofile}"`/linux-gate.so/" $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym; \
	rm $(TARGET_OUT_BREAKPAD)/kernel/$${sofile}/linux-gate.so.sym.tmp; \
	done
	endif

	# Merges all TARGET_KERNEL_DTB files together into a single kernel.dtb.
	KERNEL_DTB := $(addprefix $(KERNEL_OUT)/arch/$(KERNEL_SRC_ARCH)/boot/dts/, $(TARGET_KERNEL_DTB))
	$(PRODUCT_OUT)/kernel.dtb: $(KERNEL_BIN)
	$(hide) cat $(KERNEL_DTB) > $@

	# Produces a merged kernel and kernel.dtb file.
	$(PRODUCT_OUT)/kernel-and-dtb: $(KERNEL_BIN) $(PRODUCT_OUT)/kernel.dtb
	$(hide) cat $^ > $@

	# The list of dependencies for the final kernel.
	KERNEL_DEPS := $(KERNEL_BIN).vdso $(KERNEL_HEADERS_INSTALL)
	ifdef TARGET_KERNEL_DTB
	# If we need the DTB, include it in the build list.
	KERNEL_DEPS += $(PRODUCT_OUT)/kernel.dtb
	endif

	# The final kernel image is either the raw kernel binary or merged kernel+dtb.
	ifdef TARGET_KERNEL_DTB_APPEND
	KERNEL_IMAGE := $(PRODUCT_OUT)/kernel-and-dtb
	else
	KERNEL_IMAGE := $(KERNEL_BIN)
	endif

	# Produces the actual kernel image!
	$(PRODUCT_OUT)/kernel: $(KERNEL_IMAGE) $(KERNEL_DEPS) \| $(ACP)
	$(ACP) -fp $< $@