[Buildroot] [RFC] Building linux kernel in $(PROJECT_BUILD_DIR)

[Bernhard Fischer <rep.dot.nop@gmail.com>]

On Mon, Aug 20, 2007 at 10:34:50AM +0200, Ulf Samuelsson wrote:
>Proposed fix to allow each project to build its own linux kernel
>in $(PROJECT_BUILD_DIR)  == project_build_dir/<project>
>
>Basic approach is to unpack the linux header source in 
>"$(TOOL_BUILD_DIR)" instead of in "$(BUILD_DIR)"
>Patches are applied (some depending on BR2_<xxx>) as in current trunk,
>
>Each board can add additional patches by defining
>KERNEL_HEADERS_PATCH_DIR to point at the directory with additional
>patches (That patch just applied to get rid of AVR32 patches in 
>toolchain/kernel-headers).
>
>Headers are still installed in "$(TOOL_BUILD_DIR)/linux"
>The kernel-headers source tree is unpacked once per toolchain.
>
>The target/linux build (modules and kernel) will unpack a 
>second linux source tree in "$(PROJECT_BUILD_DIR)".
>This source tree is generated once per *project*.
>
>Since this is a fresh unpack, the same patches as were applied
>to the kernel-headers are applied to "$(PROJECT_BUILD_DIR)/linux-*".
>
>A common linux source tree for all projects is not possible, since
>different boards can require different patches to be applied.
>There is a significant risk that the linux build breaks if patches for
>one project are applied on top of patches for another project
>in the same source tree.
>
>With a single source, you therefore will have to remove the linux source
>tree each time you work on a new project.
>With a separate source, you can move between projects without removing
>the linux source directory.
>
>
>The patch is also include it as an attachement, due to linewrap.
>
>Tested this on x86/Atmel targets.
>
>Comments?
>
>
>Index: toolchain/kernel-headers/kernel-headers-new.makefile
>===================================================================
>--- toolchain/kernel-headers/kernel-headers-new.makefile	(revision
>19588)
>+++ toolchain/kernel-headers/kernel-headers-new.makefile	(arbetskopia)
>@@ -13,7 +13,7 @@
> LINUX_HEADERS_SITE:=http://www.kernel.org/pub/linux/kernel/v2.6/
> LINUX_HEADERS_SOURCE:=linux-$(LINUX_HEADERS_VERSION).tar.bz2
> LINUX_HEADERS_CAT:=$(BZCAT)
>-LINUX_HEADERS_UNPACK_DIR:=$(BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
>+LINUX_HEADERS_UNPACK_DIR:=
>$(TOOL_BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
> LINUX_HEADERS_DIR:=$(TOOL_BUILD_DIR)/linux
> LINUX_HEADERS_IS_KERNEL=y
> endif
>@@ -28,7 +28,7 @@
> LINUX_HEADERS_SITE:=http://www.kernel.org/pub/linux/kernel/v2.6/
> LINUX_HEADERS_SOURCE:=linux-$(LINUX_HEADERS_VERSION).tar.bz2
> LINUX_HEADERS_CAT:=$(BZCAT)
>-LINUX_HEADERS_UNPACK_DIR:=$(BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
>+LINUX_HEADERS_UNPACK_DIR:=
>$(TOOL_BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
> LINUX_HEADERS_DIR:=$(TOOL_BUILD_DIR)/linux
> LINUX_HEADERS_IS_KERNEL=y
> endif
>@@ -43,7 +43,7 @@
> LINUX_HEADERS_SITE:=http://www.kernel.org/pub/linux/kernel/v2.6/
> LINUX_HEADERS_SOURCE:=linux-$(LINUX_HEADERS_VERSION).tar.bz2
> LINUX_HEADERS_CAT:=$(BZCAT)
>-LINUX_HEADERS_UNPACK_DIR:=$(BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
>+LINUX_HEADERS_UNPACK_DIR:=
>$(TOOL_BUILD_DIR)/linux-$(LINUX_HEADERS_VERSION)
> LINUX_HEADERS_DIR:=$(TOOL_BUILD_DIR)/linux
> LINUX_HEADERS_IS_KERNEL=y
> endif
>@@ -56,8 +56,8 @@
> $(LINUX_HEADERS_UNPACK_DIR)/.unpacked:
>$(DL_DIR)/$(LINUX_HEADERS_SOURCE)
> 	@echo "*** Using kernel-headers generated from kernel source"
> 	rm -rf $(LINUX_HEADERS_DIR)
>-	[ -d $(BUILD_DIR) ] || $(INSTALL) -d $(BUILD_DIR)
>-	$(LINUX_HEADERS_CAT) $(DL_DIR)/$(LINUX_HEADERS_SOURCE) | tar -C
>$(BUILD_DIR) $(TAR_OPTIONS) -
>+	[ -d $(TOOL_BUILD_DIR) ] || $(INSTALL) -d $(TOOL_BUILD_DIR)

I think that the TOOL_BUILD_DIR will already exist now.
To verify, set BR2_JLEVEL=1 and execute a toplevel
make -j 64
If it is not yet created at this stage, just adding a dependency to that
dir should be sufficient (we already have a rule for it, IIRC).

>+	$(LINUX_HEADERS_CAT) $(DL_DIR)/$(LINUX_HEADERS_SOURCE) | tar -C
>$(TOOL_BUILD_DIR) $(TAR_OPTIONS) -
> 	touch $@
> 
> $(LINUX_HEADERS_UNPACK_DIR)/.patched:
>$(LINUX_HEADERS_UNPACK_DIR)/.unpacked
>Index: toolchain/kernel-headers/kernel-headers.mk
>===================================================================
>--- toolchain/kernel-headers/kernel-headers.mk	(revision 19588)
>+++ toolchain/kernel-headers/kernel-headers.mk	(arbetskopia)
>@@ -37,5 +37,6 @@
> 
> kernel-headers-dirclean:
> 	rm -rf $(LINUX_HEADERS_DIR)
>+	rm -rf $(LINUX_HEADERS_UNPACK_DIR)
> 
> .PHONY: kernel-headers
>Index: target/linux/Makefile.in
>===================================================================
>--- target/linux/Makefile.in	(revision 19588)
>+++ target/linux/Makefile.in	(arbetskopia)
>@@ -68,7 +68,7 @@
> endif
> 
> # Version of Linux AFTER patches
>-LINUX26_DIR=$(BUILD_DIR)/linux-$(LINUX26_VERSION)
>+LINUX26_DIR=$(PROJECT_BUILD_DIR)/linux-$(LINUX26_VERSION)
> 
> # for packages that need it
> LINUX_VERSION:=$(LINUX_VERSION)
>@@ -76,7 +76,9 @@
> LINUX_KERNEL=$(LINUX26_KERNEL)
> 
> # kernel patches
>+ifeq ($(strip $(LINUX26_PATCH_DIR)),)
> LINUX26_PATCH_DIR=$(BR2_BOARD_PATH)/kernel-patches/
>+endif
> __LINUX26_NO_PIC=-fPIC -fpic -DPIC
> LINUX26_MAKE_FLAGS = HOSTCC="$(HOSTCC)" HOSTCFLAGS=$(HOSTCFLAGS) \
> 	ARCH=$(KERNEL_ARCH) \
>@@ -96,20 +98,38 @@
> ifneq ($(strip $(LINUX26_VERSION)),$(strip $(LINUX_HEADERS_VERSION)))
> $(DL_DIR)/$(LINUX26_SOURCE):
> 	 $(WGET) -P $(DL_DIR) $(LINUX26_SITE)/$(LINUX26_SOURCE)
>+endif # ($(LINUX26_VERSION),$(LINUX_HEADERS_VERSION))
> 
> $(LINUX26_DIR)/.unpacked: $(DL_DIR)/$(LINUX26_SOURCE)
> 	rm -rf $(LINUX26_DIR)
>-	$(LINUX26_BZCAT) $(DL_DIR)/$(LINUX26_SOURCE) | tar -C $(BUILD_DIR)
>$(TAR_OPTIONS) -
>+	$(LINUX26_BZCAT) $(DL_DIR)/$(LINUX26_SOURCE) | tar -C
>$(PROJECT_BUILD_DIR) $(TAR_OPTIONS) -
> ifneq ($(DOWNLOAD_LINUX26_VERSION),$(LINUX26_VERSION))
> 	# Rename the dir from the downloaded version to the AFTER patch
>version
>-	mv -f $(BUILD_DIR)/linux-$(DOWNLOAD_LINUX26_VERSION) $(LINUX26_DIR)
>+	mv -f $(PROJECT_BUILD_DIR)/linux-$(DOWNLOAD_LINUX26_VERSION)
>$(LINUX26_DIR)
> endif
> 	touch $@
> 
> $(LINUX26_DIR)/.patched: $(LINUX26_DIR)/.unpacked
>-	toolchain/patch-kernel.sh $(LINUX26_DIR) $(LINUX26_PATCH_DIR) \*.patch
>+	toolchain/patch-kernel.sh $(LINUX26_DIR) toolchain/kernel-headers \
>+		linux-$(LINUX26_VERSION)-\*.patch{,.gz,.bz2}
>+ifeq ($(BR2_KERNEL_HEADERS_IPMI),y)
>+	toolchain/patch-kernel.sh $(LINUX26_DIR) toolchain/kernel-headers/ipmi
>\
>+		linux-$(LINUX26_VERSION)-\*.patch{,.gz,.bz2}
>+endif
>+ifeq ($(BR2_KERNEL_HEADERS_LZMA),y)
>+	toolchain/patch-kernel.sh $(LINUX26_DIR) toolchain/kernel-headers/lzma
>\
>+		linux-$(LINUX26_VERSION)-\*.patch{,.gz,.bz2}
>+endif
>+ifeq ($(BR2_KERNEL_HEADERS_PATCH_DIR),y)
>+	toolchain/patch-kernel.sh $(LINUX26_DIR) $(KERNEL_HEADERS_PATCH_DIR) \
>+		linux-$(LINUX26_VERSION)-\*.patch{,.gz,.bz2}
>+endif
>+ifeq ($(BR2_PACKAGE_OPENSWAN),y)
>+	toolchain/patch-kernel.sh $(LINUX_HEADERS_UNPACK_DIR) package/openswan
>\
>+		linux-$(LINUX26_VERSION)-\*.patch{,.gz,.bz2}
>+endif
>+	toolchain/patch-kernel.sh $(LINUX26_DIR) $(LINUX26_PATCH_DIR)

Hardcoding these is very, very ugly.

>linux-$(LINUX26_VERSION)\*.patch
> 	touch $@
>-endif # ($(LINUX26_VERSION),$(LINUX_HEADERS_VERSION))
> 
> $(LINUX26_DIR)/.configured: $(LINUX26_DIR)/.patched $(LINUX26_KCONFIG)
> 	cp -dpf $(LINUX26_KCONFIG) $(LINUX26_DIR)/.config
>

Did you test this with the old, deprecated headers, with new headers ==
src and new-headers != src ?

If so, then please apply with abovementioned fix for the mkdir.

thanks,