[OE-core] [PATCH v2] kernel-devsrc: restructure for out of tree (and on target) module builds
Bruce Ashfield
bruce.ashfield at windriver.com
Wed Feb 28 21:12:06 UTC 2018
On 2018-02-28 4:10 PM, Mark Hatle wrote:
> One question, below inline:
>
> On 2/28/18 1:20 PM, Bruce Ashfield wrote:
>> The existing kernel-devsrc package starts with a full copy of the kernel
>> source and then starts to strip out elements that are not required.
>>
>> This results in extra time (I/O) and extra space being taken up in the
>> final package. The main purpose of the kernel-devsrc package has been to
>> build modules against the running kernel, not to include a full copy of
>> the source code for re-building the kernel. The end result was a
>> 600M kernel-devsrc package.
>>
>> This restructuring of the package uses an approach similar to other
>> distros, where the kernel-devsrc package is for building against the
>> running kernel and uses a curated set of copied infrastructure, versus
>> a mass copy of the entire kernel.
>>
>> The differences in this approach versus other is largely due to the
>> architecture support and the split build/source directory of the
>> kernel.
>>
>> The result is a kernel-devsrc package of about 10M, which is capable
>> of running "make scripts" and compiling kernel modules against the
>> running kernel.
>>
>> Along with the changes to the copying of the infrascture, we also
>> have the following changes:
>>
>> - a better/more explicit listing of dependencies for on-target
>> builds of "make scripts" or "make modules_prepare"
>>
>> - The kernel source is installed into /lib/modules/<version>/build
>> and a symlink created from /usr/src/kernel to the new location.
>> This aligns with the standard location for module support
>> code
>>
>> - There is also a symlink from /lib/modules/<version>/source -> build
>> to reserve a spot for a new package that is simply the kernel
>> source. That package is not part of this update.
>>
>> [YOCTO #12535]
>>
>> Signed-off-by: Bruce Ashfield <bruce.ashfield at windriver.com>
>> ---
>>
>> v2: fix arch/arm devsrc builds
>>
>> The arch conditional code for ARM was using invalid variables for the
>> current version of the recipe. Those are now fixed, and we can package
>> for ARM.
>>
>> meta/recipes-kernel/linux/kernel-devsrc.bb | 178 ++++++++++++++++++++++-------
>> 1 file changed, 138 insertions(+), 40 deletions(-)
>>
>> diff --git a/meta/recipes-kernel/linux/kernel-devsrc.bb b/meta/recipes-kernel/linux/kernel-devsrc.bb
>> index c1b5b7786d7c..738290ac2dc3 100644
>> --- a/meta/recipes-kernel/linux/kernel-devsrc.bb
>> +++ b/meta/recipes-kernel/linux/kernel-devsrc.bb
>> @@ -30,50 +30,148 @@ do_populate_sysroot[noexec] = "1"
>> S = "${STAGING_KERNEL_DIR}"
>> B = "${STAGING_KERNEL_BUILDDIR}"
>>
>> -KERNEL_VERSION = "${@get_kernelversion_headers('${S}')}"
>> -
>
> I see this is removed, but later items reference KERNEL_VERSION. Is that
> defined elsewhere?
Yup. It comes from the base classes. That variable in the current
form, is actually empty.
Bruce
>
> --Mark
>
>> PACKAGE_ARCH = "${MACHINE_ARCH}"
>>
>> +KERNEL_BUILD_ROOT="/lib/modules/"
>> +
>> do_install() {
>> - kerneldir=${D}${KERNEL_SRC_PATH}
>> - install -d $kerneldir
>> -
>> - #
>> - # Copy the staging dir source (and module build support) into the devsrc structure.
>> - # We can keep this copy simple and take everything, since a we'll clean up any build
>> - # artifacts afterwards, and the extra i/o is not significant
>> - #
>> - cd ${B}
>> - find . -type d -name '.git*' -prune -o -path '.debug' -prune -o -type f -print0 | cpio --null -pdlu $kerneldir
>> - cd ${S}
>> - find . -type d -name '.git*' -prune -o -type d -name '.kernel-meta' -prune -o -type f -print0 | cpio --null -pdlu $kerneldir
>> -
>> - # Explicitly set KBUILD_OUTPUT to ensure that the image directory is cleaned and not
>> - # The main build artifacts. We clean the directory to avoid QA errors on mismatched
>> - # architecture (since scripts and helpers are native format).
>> - KBUILD_OUTPUT="$kerneldir"
>> - oe_runmake -C $kerneldir CC="${KERNEL_CC}" LD="${KERNEL_LD}" clean _mrproper_scripts
>> - # make clean generates an absolute path symlink called "source"
>> - # in $kerneldir points to $kerneldir, which doesn't make any
>> - # sense, so remove it.
>> - if [ -L $kerneldir/source ]; then
>> - bbnote "Removing $kerneldir/source symlink"
>> - rm -f $kerneldir/source
>> - fi
>> -
>> - # As of Linux kernel version 3.0.1, the clean target removes
>> - # arch/powerpc/lib/crtsavres.o which is present in
>> - # KBUILD_LDFLAGS_MODULE, making it required to build external modules.
>> - if [ ${ARCH} = "powerpc" ]; then
>> - mkdir -p $kerneldir/arch/powerpc/lib/
>> - cp ${B}/arch/powerpc/lib/crtsavres.o $kerneldir/arch/powerpc/lib/crtsavres.o
>> - fi
>> -
>> - chown -R root:root ${D}
>> + kerneldir=${D}${KERNEL_BUILD_ROOT}${KERNEL_VERSION}
>> + install -d $kerneldir
>> +
>> + # create the directory structure
>> + rm -f $kerneldir/build
>> + rm -f $kerneldir/source
>> + mkdir -p $kerneldir/build
>> +
>> + # for compatibility with some older variants of this package, we
>> + # create a /usr/src/kernel symlink to /lib/modules/<version>/source
>> + mkdir -p ${D}/usr/src
>> + (
>> + cd ${D}/usr/src
>> + ln -s ${KERNEL_BUILD_ROOT}${KERNEL_VERSION}/source kernel
>> + )
>> +
>> + # for on target purposes, we unify build and source
>> + (
>> + cd $kerneldir
>> + ln -s build source
>> + )
>> +
>> + # first copy everything
>> + (
>> + cd ${S}
>> + cp --parents $(find -type f -name "Makefile*" -o -name "Kconfig*") $kerneldir/build
>> + )
>> +
>> + # then drop all but the needed Makefiles/Kconfig files
>> + rm -rf $kerneldir/build/Documentation
>> + rm -rf $kerneldir/build/scripts
>> + rm -rf $kerneldir/build/include
>> +
>> + # now copy in parts from the build that we'll need later
>> + (
>> + cd ${B}
>> +
>> + cp Module.symvers $kerneldir/build
>> + cp System.map* $kerneldir/build
>> + if [ -s Module.markers ]; then
>> + cp Module.markers $kerneldir/build
>> + fi
>> +
>> + cp .config $kerneldir/build
>> +
>> + # TODO: this scripts copy will likely blow up QA, so for now, we
>> + # require a more complex 'make scripts' to restore these, versus
>> + # copying them here. Left as a reference to indicate that we
>> + # know the scripts must be dealt with.
>> + # cp -a scripts $kerneldir/build
>> +
>> + if [ -f tools/objtool/objtool ]; then
>> + cp -a tools/objtool/objtool $kerneldir/build/tools/objtool/
>> + fi
>> + if [ -d arch/${ARCH}/scripts ]; then
>> + cp -a arch/${ARCH}/scripts $kerneldir/build/arch/${ARCH}
>> + fi
>> + if [ -f arch/${ARCH}/*lds ]; then
>> + cp -a arch/${ARCH}/*lds $kerneldir/build/arch/${ARCH}
>> + fi
>> +
>> + rm -f $kerneldir/build/scripts/*.o
>> + rm -f $kerneldir/build/scripts/*/*.o
>> +
>> + if [ "${ARCH}" = "powerpc" ]; then
>> + cp -a --parents arch/powerpc/lib/crtsavres.[So] $kerneldir/build/
>> + fi
>> +
>> + cp -a include $kerneldir/build/include
>> + )
>> +
>> + # now grab the chunks from the source tree that we need
>> + (
>> + cd ${S}
>> +
>> + cp -a scripts $kerneldir/build
>> + if [ "${ARCH}" = "arm64" ]; then
>> + # arch/arm64/include/asm/xen references arch/arm
>> + cp -a --parents arch/arm/include/asm/xen $kerneldir/build/
>> + # arch/arm64/include/asm/opcodes.h references arch/arm
>> + cp -a --parents arch/arm/include/asm/opcodes.h $kerneldir/build/
>> + fi
>> +
>> + # include the machine specific headers for ARM variants, if available.
>> + if [ "${ARCH}" = "arm" ]; then
>> + cp -a --parents arch/${ARCH}/mach-*/include $kerneldir/build/
>> +
>> + # include a few files for 'make prepare'
>> + cp -a --parents arch/arm/tools/gen-mach-types $kerneldir/build/
>> + cp -a --parents arch/arm/tools/mach-types $kerneldir/build/
>> + fi
>> +
>> + if [ -d arch/${ARCH}/include ]; then
>> + cp -a --parents arch/${ARCH}/include $kerneldir/build/
>> + fi
>> +
>> + cp -a include $kerneldir/build
>> +
>> + if [ "${ARCH}" = "x86" ]; then
>> + # files for 'make prepare' to succeed with kernel-devel
>> + cp -a --parents arch/x86/entry/syscalls/syscall_32.tbl $kerneldir/build/
>> + cp -a --parents arch/x86/entry/syscalls/syscalltbl.sh $kerneldir/build/
>> + cp -a --parents arch/x86/entry/syscalls/syscallhdr.sh $kerneldir/build/
>> + cp -a --parents arch/x86/entry/syscalls/syscall_64.tbl $kerneldir/build/
>> + cp -a --parents arch/x86/tools/relocs_32.c $kerneldir/build/
>> + cp -a --parents arch/x86/tools/relocs_64.c $kerneldir/build/
>> + cp -a --parents arch/x86/tools/relocs.c $kerneldir/build/
>> + cp -a --parents arch/x86/tools/relocs_common.c $kerneldir/build/
>> + cp -a --parents arch/x86/tools/relocs.h $kerneldir/build/
>> + cp -a --parents tools/include/tools/le_byteshift.h $kerneldir/build/
>> + cp -a --parents tools/include/tools/be_byteshift.h $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/purgatory.c $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/sha256.h $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/sha256.c $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/stack.S $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/string.c $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/setup-x86_64.S $kerneldir/build/
>> + cp -a --parents arch/x86/purgatory/entry64.S $kerneldir/build/
>> + cp -a --parents arch/x86/boot/string.h $kerneldir/build/
>> + cp -a --parents arch/x86/boot/string.c $kerneldir/build/
>> + cp -a --parents arch/x86/boot/ctype.h $kerneldir/build/
>> + fi
>> + )
>> +
>> + # Make sure the Makefile and version.h have a matching timestamp so that
>> + # external modules can be built
>> + touch -r $kerneldir/build/Makefile $kerneldir/build/include/generated/uapi/linux/version.h
>> +
>> + # Copy .config to include/config/auto.conf so "make prepare" is unnecessary.
>> + cp $kerneldir/build/.config $kerneldir/build/include/config/auto.conf
>> +
>> + chown -R root:root ${D}
>> }
>> +
>> # Ensure we don't race against "make scripts" during cpio
>> do_install[lockfiles] = "${TMPDIR}/kernel-scripts.lock"
>>
>> -PACKAGES = "kernel-devsrc"
>> -FILES_${PN} = "${KERNEL_SRC_PATH}"
>> -RDEPENDS_${PN} = "bc"
>> +FILES_${PN} = "${KERNEL_BUILD_ROOT} ${KERNEL_SRC_PATH}"
>> +FILES_${PN}-dbg += "${KERNEL_BUILD_ROOT}*/build/scripts/*/.debug/*"
>> +RDEPENDS_${PN} = "bc glibc-utils"
>>
>
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