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: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
This commit is contained in:
Thomas Petazzoni 2010-04-03 18:46:46 +02:00
parent cd7459b4ee
commit 487e21cff6
4 changed files with 253 additions and 1 deletions

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@ -295,4 +295,4 @@ source "fs/Config.in"
source "boot/Config.in"
source "target/Config.in"
source "linux/Config.in"

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@ -323,6 +323,7 @@ endif
include boot/common.mk
include target/Makefile.in
include linux/linux.mk
include fs/common.mk
TARGETS+=erase-fakeroots

133
linux/Config.in Normal file
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@ -0,0 +1,133 @@
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

118
linux/linux.mk Normal file
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@ -0,0 +1,118 @@
###############################################################################
#
# 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