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>

diff --git a/Config.in b/Config.in
index f5eb859070693267c2c21450aec7e6f0e1e6fb4d..0a07576da141bb2e5758f2e2a93fcd4c8a103d6c 100644 (file)
--- a/Config.in
+++ b/Config.in
@@ -295,4 +295,4 @@ source "fs/Config.in"
 
 source "boot/Config.in"
 
-source "target/Config.in"
+source "linux/Config.in"

diff --git a/Makefile b/Makefile
index 7e00b657e71cc0206db6c9910f5c1c90972b49ba..3bf23d9c41042d1d257f2f90dc9c18215095a6db 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -323,6 +323,7 @@ endif
 
 include boot/common.mk
 include target/Makefile.in
+include linux/linux.mk
 include fs/common.mk
 
 TARGETS+=erase-fakeroots

diff --git a/linux/Config.in b/linux/Config.in
new file mode 100644 (file)
index 0000000..d8a5157
--- /dev/null
+++ b/linux/Config.in
@@ -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

diff --git a/linux/linux.mk b/linux/linux.mk
new file mode 100644 (file)
index 0000000..3e91eca
--- /dev/null
+++ b/linux/linux.mk
@@ -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