Commit 487e21cf authored by Thomas Petazzoni's avatar Thomas Petazzoni
Browse files

New, simpler, infrastructure for building the Linux kernel 



This patch introduces a single, simple, infrastructure to build the
Linux kernel. The configuration is limited to :

 * Kernel version: a fixed recent stable version, same as kernel
   headers version (for internal toolchains only), custom stable
   version, or custom tarball URL

 * Kernel patch: either a local file, directory or an URL

 * Kernel configuration: either the name of a defconfig or the
   location of a custom configuration file

 * Kernel image: either uImage, bzImage, zImage or vmlinux.

Signed-off-by: default avatarThomas Petazzoni <thomas.petazzoni@free-electrons.com>
parent cd7459b4

Config.in

+1 −1
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@@ -295,4 +295,4 @@ source "fs/Config.in" 


source "boot/Config.in"



source "target/Config.in"
 
source "linux/Config.in"

Makefile

+1 −0
Original line number Diff line number Diff line
@@ -323,6 +323,7 @@ endif 


include boot/common.mk

include target/Makefile.in

include linux/linux.mk

include fs/common.mk



TARGETS+=erase-fakeroots

linux/Config.in

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menu "Kernel"



config BR2_LINUX_KERNEL

	bool "Linux Kernel"

	help

	  Enable this option if you want to build a Linux kernel for

	  your embedded device



if BR2_LINUX_KERNEL



#

# Version selection. We provide the choice between:

#

#  1. A single fairly recent stable kernel version

#  2. In case an internal toolchain has been built, the same kernel

#     version as the kernel headers

#  3. A custom stable version

#  4. A custom tarball

#

choice

	prompt "Kernel version"

	default BR2_LINUX_KERNEL_2_6_34



config BR2_LINUX_KERNEL_2_6_34

	bool "2.6.34"



config BR2_LINUX_KERNEL_SAME_AS_HEADERS

	bool "Same as toolchain kernel headers"

	depends on BR2_TOOLCHAIN_BUILDROOT

	help

	  This option will re-use the same kernel sources as the one

	  that have been used for the kernel headers of the

	  cross-compiling toolchain. Having the same version for the

	  kernel running on the system and for the kernel headers is

	  not a requirement, but using the same version allows to

	  download only one tarball of the kernel sources.



config BR2_LINUX_KERNEL_CUSTOM_VERSION

	bool "Custom version"

	help

	  This option allows to use a specific 2.6.x or 2.6.x.y

	  official versions, as available on kernel.org



config BR2_LINUX_KERNEL_CUSTOM_TARBALL

	bool "Custom tarball"

	help

	  This option allows to specify the http or ftp location of a

	  specific kernel source tarball



endchoice



config BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE

	string "Kernel version"

	depends on BR2_LINUX_KERNEL_CUSTOM_VERSION

	default "2.6.34"



config BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION

	string "URL of custom kernel tarball"

	depends on BR2_LINUX_KERNEL_CUSTOM_TARBALL



config BR2_LINUX_KERNEL_VERSION

	string

	default "2.6.34" if BR2_LINUX_KERNEL_2_6_34

	default BR2_DEFAULT_KERNEL_HEADERS if BR2_LINUX_KERNEL_SAME_AS_HEADERS

	default BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE if BR2_LINUX_KERNEL_CUSTOM_VERSION

	default "custom" if BR2_LINUX_KERNEL_CUSTOM_TARBALL



#

# Patch selection

#



config BR2_LINUX_KERNEL_PATCH

	string "Custom kernel patch"

	help

         The location can be an URL, a file path, or a directory. In

         the case of a directory, all files matching linux-*.patch

         will be applied.



#

# Configuration selection

#



choice

	prompt "Kernel configuration"

	default BR2_LINUX_KERNEL_USE_DEFCONFIG



config BR2_LINUX_KERNEL_USE_DEFCONFIG

	bool "Using a defconfig"



config BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG

	bool "Using a custom config file"



endchoice



config BR2_LINUX_KERNEL_DEFCONFIG

	string "Defconfig name"

	depends on BR2_LINUX_KERNEL_USE_DEFCONFIG

	help

	 Name of the defconfig file to use, without the leading

	 _defconfig



config BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE

	string "Configuration file path"

	depends on BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG

	help

	  Path to the kernel configuration file



#

# Binary format

#



choice

	prompt "Kernel binary format"

	default BR2_LINUX_KERNEL_UIMAGE if !BR2_i386 && !BR2_x86_64

	default BR2_LINUX_KERNEL_BZIMAGE if BR2_i386 || BR2_x86_64



config BR2_LINUX_KERNEL_UIMAGE

	bool "uImage"



config BR2_LINUX_KERNEL_BZIMAGE

	bool "bzImage"



config BR2_LINUX_KERNEL_ZIMAGE

	bool "zImage"



config BR2_LINUX_KERNEL_VMLINUX

	bool "vmlinux"



endchoice



endif # BR2_LINUX_KERNEL



endmenu

linux/linux.mk

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###############################################################################

#

# Linux kernel 2.6 target

#

###############################################################################

LINUX26_VERSION=$(call qstrip,$(BR2_LINUX_KERNEL_VERSION))



# Compute LINUX26_SOURCE and LINUX26_SITE from the configuration

ifeq ($(LINUX26_VERSION),custom)

LINUX26_TARBALL:=$(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION))

LINUX26_SITE:=$(dir $(LINUX26_TARBALL))

LINUX26_SOURCE:=$(notdir $(LINUX26_TARBALL))

else

LINUX26_SOURCE:=linux-$(LINUX26_VERSION).tar.bz2

LINUX26_SITE:=$(BR2_KERNEL_MIRROR)/linux/kernel/v2.6/

endif



LINUX26_DIR:=$(BUILD_DIR)/linux-$(LINUX26_VERSION)

LINUX26_PATCH=$(call qstrip,$(BR2_LINUX_KERNEL_PATCH))



LINUX26_MAKE_FLAGS = \

	HOSTCC="$(HOSTCC)" \

	HOSTCFLAGS="$(HOSTCFLAGS)" \

	ARCH=$(KERNEL_ARCH) \

	INSTALL_MOD_PATH=$(TARGET_DIR) \

	CROSS_COMPILE=$(TARGET_CROSS) \

	LDFLAGS="$(TARGET_LDFLAGS)" \

	LZMA="$(LZMA)"



# Get the real Linux version, which tells us where kernel modules are

# going to be installed in the target filesystem.

LINUX26_VERSION_PROBED = $(shell $(MAKE) $(LINUX26_MAKE_FLAGS) -C $(LINUX26_DIR) --no-print-directory -s kernelrelease)



ifeq ($(BR2_LINUX_KERNEL_UIMAGE),y)

LINUX26_IMAGE_NAME=uImage

LINUX26_DEPENDENCIES+=$(MKIMAGE)

else ifeq ($(BR2_LINUX_KERNEL_BZIMAGE),y)

LINUX26_IMAGE_NAME=bzImage

else ifeq ($(BR2_LINUX_KERNEL_ZIMAGE),y)

LINUX26_IMAGE_NAME=zImage

else ifeq ($(BR2_LINUX_KERNEL_VMLINUX),y)

LINUX26_IMAGE_NAME=vmlinux.bin

endif



LINUX26_IMAGE_PATH=$(LINUX26_DIR)/arch/$(KERNEL_ARCH)/boot/$(LINUX26_IMAGE_NAME)



# Download

$(LINUX26_DIR)/.stamp_downloaded:

	@$(call MESSAGE,"Downloading kernel")

	$(call DOWNLOAD,$(LINUX26_SITE),$(LINUX26_SOURCE))

ifneq ($(filter ftp://% http://%,$(LINUX26_PATCH)),)

	$(call DOWNLOAD,$(dir $(LINUX26_PATCH)),$(notdir $(LINUX26_PATCH)))

endif

	mkdir -p $(@D)

	touch $@



# Extraction

$(LINUX26_DIR)/.stamp_extracted: $(LINUX26_DIR)/.stamp_downloaded

	@$(call MESSAGE,"Extracting kernel")

	mkdir -p $(@D)

	$(Q)$(INFLATE$(suffix $(LINUX26_SOURCE))) $(DL_DIR)/$(LINUX26_SOURCE) | \

		tar -C $(@D) $(TAR_STRIP_COMPONENTS)=1 $(TAR_OPTIONS) -

	$(Q)touch $@



# Patch

$(LINUX26_DIR)/.stamp_patched: $(LINUX26_DIR)/.stamp_extracted

	@$(call MESSAGE,"Patching kernel")

ifneq ($(LINUX26_PATCH),)

ifneq ($(filter ftp://% http://%,$(LINUX26_PATCH)),)

	toolchain/patch-kernel.sh $(@D) $(DL_DIR) $(notdir $(LINUX26_PATCH))

else ifeq ($(shell test -d $(LINUX26_PATCH) && echo "dir"),dir)

	toolchain/patch-kernel.sh $(@D) $(LINUX26_PATCH) linux-\*.patch

else

	toolchain/patch-kernel.sh $(@D) $(dir $(LINUX26_PATCH)) $(notdir $(LINUX26_PATCH))

endif

endif

	$(Q)touch $@





# Configuration

$(LINUX26_DIR)/.stamp_configured: $(LINUX26_DIR)/.stamp_patched

	@$(call MESSAGE,"Configuring kernel")

ifeq ($(BR2_LINUX_KERNEL_USE_DEFCONFIG),y)

	$(TARGET_MAKE_ENV) $(MAKE1) $(LINUX26_MAKE_FLAGS) -C $(@D) $(call qstrip,$(BR2_LINUX_KERNEL_DEFCONFIG))_defconfig

else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y)

	cp $(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE) $(@D)/.config

endif

	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX26_MAKE_FLAGS) -C $(@D) oldconfig

	$(Q)touch $@



# Compilation

$(LINUX26_DIR)/.stamp_compiled: $(LINUX26_DIR)/.stamp_configured

	@$(call MESSAGE,"Compiling kernel")

	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX26_MAKE_FLAGS) -C $(@D) $(LINUX26_IMAGE_NAME)

	@if [ $(shell grep -c "CONFIG_MODULES=y" $(LINUX26_DIR)/.config) != 0 ] ; then 	\

		$(TARGET_MAKE_ENV) $(MAKE) $(LINUX26_MAKE_FLAGS) -C $(@D) modules ;	\

	fi

	$(Q)touch $@



# Installation

$(LINUX26_DIR)/.stamp_installed: $(LINUX26_DIR)/.stamp_compiled

	@$(call MESSAGE,"Installing kernel")

	cp $(LINUX26_IMAGE_PATH) $(BINARIES_DIR)

	# Install modules and remove symbolic links pointing to build

	# directories, not relevant on the target

	@if [ $(shell grep -c "CONFIG_MODULES=y" $(LINUX26_DIR)/.config) != 0 ] ; then 	\

		$(TARGET_MAKE_ENV) $(MAKE1) $(LINUX26_MAKE_FLAGS) -C $(@D) 		\

			INSTALL_MOD_PATH=$(TARGET_DIR) modules_install ;		\

		rm -f $(TARGET_DIR)/lib/modules/$(LINUX26_VERSION_PROBED)/build ;	\

		rm -f $(TARGET_DIR)/lib/modules/$(LINUX26_VERSION_PROBED)/source ;	\

	fi

	$(Q)touch $@



linux26: $(LINUX26_DEPENDENCIES) $(LINUX26_DIR)/.stamp_installed



ifeq ($(BR2_LINUX_KERNEL),y)

TARGETS+=linux26

endif