Re: [v2 PATCH] kernel.bbclass, image.bbclass: Implement kernel INITRAMFS dependency and bundling

[Khem Raj <raj.khem@gmail.com>]

On Thu, Aug 22, 2013 at 4:04 PM, Jason Wessel
<jason.wessel@windriver.com> wrote:
> This patch aims to fix the following two cases for the INITRAMFS generation.
>   1) Allow an image recipe to specify a paired INITRAMFS recipe such
>      as core-image-minimal-initramfs.  This allows building a base
>      image which always generates the needed initramfs image in one step
>   2) Allow building a single binary which contains a kernel and
>      the initramfs.

I think this could be a bit simpler. Have a full kernel image recipe (
kernel + initramfs)
separate. It fits into the equation nicely. The final image can bundle
initramfs which has modules from practically same kernel build is
staged step 1 of kernel build which
automatically happens today for any image build.

The new recipe for kernel+initramfs requires the existing kernel
recipes and tweaks the .config to enable INITRAMFS_IMAGE

You can share the sources for both stages where kernel is built like
gcc is putting the sources under work-shared and building all gcc
recipes out of this location.


>
> A key requirement of the initramfs is to be able to add kernel
> modules.  The current implementation of the INITRAMFS_IMAGE variable
> has a circular dependency when using kernel modules in the initramfs
> image.bb file that is caused by kernel.bbclass trying to build the
> initramfs before the kernel's do_install rule.
>
> The solution for this problem is to have the kernel's
> do_bundle_initramfs_image task depend on the do_rootfs from the
> INITRAMFS_IMAGE and not some intermediate point.  The image.bbclass
> will also sets up dependencies to make the initramfs creation task run
> last.
>
> The code to bundle the kernel and initramfs together has been added.
> At a high level, all it is doing is invoking a second compilation of
> the kernel but changing the value of CONFIG_INITRAMFS_SOURCE to point
> to the generated initramfs from the image recipe.
>
> [YOCTO #4072]
>
> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
> Acked-by: Bruce Ashfield <bruce.ashfield@windriver.com>
>
> ---
>  meta/classes/image.bbclass  |   12 ++++++
>  meta/classes/kernel.bbclass |   96 +++++++++++++++++++++++++++++++++++++------
>  meta/conf/local.conf.sample |   20 +++++++++
>  3 files changed, 116 insertions(+), 12 deletions(-)
>
> diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
> index 909702a..23967ec 100644
> --- a/meta/classes/image.bbclass
> +++ b/meta/classes/image.bbclass
> @@ -130,6 +130,10 @@ python () {
>      d.setVar('MULTILIB_VENDORS', ml_vendor_list)
>
>      check_image_features(d)
> +    initramfs_image = d.getVar('INITRAMFS_IMAGE', True) or ""
> +    if initramfs_image != "":
> +        d.appendVarFlag('do_build', 'depends', " %s:do_bundle_initramfs" %  d.getVar('PN', True))
> +        d.appendVarFlag('do_bundle_initramfs', 'depends', " %s:do_rootfs" % initramfs_image)
>  }
>
>  #
> @@ -629,3 +633,11 @@ do_package_write_deb[noexec] = "1"
>  do_package_write_rpm[noexec] = "1"
>
>  addtask rootfs before do_build
> +# Allow the kernel to be repacked with the initramfs and boot image file as a single file
> +do_bundle_initramfs[depends] += "virtual/kernel:do_bundle_initramfs"
> +do_bundle_initramfs[nostamp] = "1"
> +do_bundle_initramfs[noexec] = "1"
> +do_bundle_initramfs () {
> +       :
> +}
> +addtask bundle_initramfs after do_rootfs
> diff --git a/meta/classes/kernel.bbclass b/meta/classes/kernel.bbclass
> index e039dfc..8cf66ce 100644
> --- a/meta/classes/kernel.bbclass
> +++ b/meta/classes/kernel.bbclass
> @@ -9,6 +9,7 @@ INHIBIT_DEFAULT_DEPS = "1"
>  KERNEL_IMAGETYPE ?= "zImage"
>  INITRAMFS_IMAGE ?= ""
>  INITRAMFS_TASK ?= ""
> +INITRAMFS_IMAGE_BUNDLE ?= ""
>
>  python __anonymous () {
>      kerneltype = d.getVar('KERNEL_IMAGETYPE', True) or ''
> @@ -19,7 +20,15 @@ python __anonymous () {
>
>      image = d.getVar('INITRAMFS_IMAGE', True)
>      if image:
> -        d.setVar('INITRAMFS_TASK', '${INITRAMFS_IMAGE}:do_rootfs')
> +        d.appendVarFlag('do_bundle_initramfs', 'depends', ' ${INITRAMFS_IMAGE}:do_rootfs')
> +
> +    # NOTE: setting INITRAMFS_TASK is for backward compatibility
> +    #       The preferred method is to set INITRAMFS_IMAGE, because
> +    #       this INITRAMFS_TASK has circular dependency problems
> +    #       if the initramfs requires kernel modules
> +    image_task = d.getVar('INITRAMFS_TASK', True)
> +    if image_task:
> +        d.appendVarFlag('do_configure', 'depends', ' ${INITRAMFS_TASK}')
>  }
>
>  inherit kernel-arch deploy
> @@ -72,9 +81,82 @@ KERNEL_SRC_PATH = "/usr/src/kernel"
>
>  KERNEL_IMAGETYPE_FOR_MAKE = "${@(lambda s: s[:-3] if s[-3:] == ".gz" else s)(d.getVar('KERNEL_IMAGETYPE', True))}"
>
> +copy_initramfs() {
> +       echo "Copying initramfs into ./usr ..."
> +       # Find and use the first initramfs image archive type we find
> +       rm -f ${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.cpio
> +       for img in cpio.gz cpio.lzo cpio.lzma cpio.xz; do
> +               if [ -e "${DEPLOY_DIR_IMAGE}/${INITRAMFS_IMAGE}-${MACHINE}.$img" ]; then
> +                       cp ${DEPLOY_DIR_IMAGE}/${INITRAMFS_IMAGE}-${MACHINE}.$img ${B}/usr/.
> +                       case $img in
> +                       *gz)
> +                               echo "gzip decompressing image"
> +                               gunzip -f ${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.$img
> +                               break
> +                               ;;
> +                       *lzo)
> +                               echo "lzo decompressing image"
> +                               lzop -df ${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.$img
> +                               break
> +                               ;;
> +                       *lzma)
> +                               echo "lzma decompressing image"
> +                               lzmash -df ${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.$img
> +                               break
> +                               ;;
> +                       *xz)
> +                               echo "xz decompressing image"
> +                               xz -df ${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.$img
> +                               break
> +                               ;;
> +                       esac
> +               fi
> +       done
> +       echo "Finished copy of initramfs into ./usr"
> +}
> +
> +INITRAMFS_BASE_NAME = "${KERNEL_IMAGETYPE}-initramfs-${PV}-${PR}-${MACHINE}-${DATETIME}"
> +INITRAMFS_BASE_NAME[vardepsexclude] = "DATETIME"
> +do_bundle_initramfs () {
> +       if [ ! -z "${INITRAMFS_IMAGE}" -a x"${INITRAMFS_IMAGE_BUNDLE}" = x1 ]; then
> +               echo "Creating a kernel image with a bundled initramfs..."
> +               copy_initramfs
> +               if [ -e ${KERNEL_OUTPUT} ] ; then
> +                       mv -f ${KERNEL_OUTPUT} ${KERNEL_OUTPUT}.bak
> +               fi
> +               use_alternate_initrd=CONFIG_INITRAMFS_SOURCE=${B}/usr/${INITRAMFS_IMAGE}-${MACHINE}.cpio
> +               kernel_do_compile
> +               mv -f ${KERNEL_OUTPUT} ${KERNEL_OUTPUT}.initramfs
> +               mv -f ${KERNEL_OUTPUT}.bak ${KERNEL_OUTPUT}
> +               # Update install area
> +               echo "There is kernel image bundled with initramfs: ${B}/${KERNEL_OUTPUT}.initramfs"
> +               install -m 0644 ${B}/${KERNEL_OUTPUT}.initramfs ${D}/boot/${KERNEL_IMAGETYPE}-initramfs-${MACHINE}.bin
> +               echo "${B}/${KERNEL_OUTPUT}.initramfs"
> +               cd ${B}
> +               # Update deploy directory
> +               if [ -e "${KERNEL_OUTPUT}.initramfs" ]; then
> +                       echo "Copying deploy kernel-initramfs image and setting up links..."
> +                       initramfs_base_name=${INITRAMFS_BASE_NAME}
> +                       initramfs_symlink_name=${KERNEL_IMAGETYPE}-initramfs-${MACHINE}
> +                       install -m 0644 ${KERNEL_OUTPUT}.initramfs ${DEPLOY_DIR_IMAGE}/${initramfs_base_name}.bin
> +                       cd ${DEPLOY_DIR_IMAGE}
> +                       ln -sf ${initramfs_base_name}.bin ${initramfs_symlink_name}.bin
> +               fi
> +       fi
> +}
> +do_bundle_initramfs[nostamp] = "1"
> +addtask bundle_initramfs after do_compile
> +
>  kernel_do_compile() {
>         unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS MACHINE
> -       oe_runmake ${KERNEL_IMAGETYPE_FOR_MAKE} ${KERNEL_ALT_IMAGETYPE} CC="${KERNEL_CC}" LD="${KERNEL_LD}" ${KERNEL_EXTRA_ARGS}
> +       # The $use_alternate_initrd is only set from
> +       # do_bundle_initramfs() This variable is specifically for the
> +       # case where we are making a second pass at the kernel
> +       # compilation and we want to force the kernel build to use a
> +       # different initramfs image.  The way to do that in the kernel
> +       # is to specify:
> +       # make ...args... CONFIG_INITRAMFS_SOURCE=some_other_initramfs.cpio
> +       oe_runmake ${KERNEL_IMAGETYPE_FOR_MAKE} ${KERNEL_ALT_IMAGETYPE} CC="${KERNEL_CC}" LD="${KERNEL_LD}" ${KERNEL_EXTRA_ARGS} $use_alternate_initrd
>         if test "${KERNEL_IMAGETYPE_FOR_MAKE}.gz" = "${KERNEL_IMAGETYPE}"; then
>                 gzip -9c < "${KERNEL_IMAGETYPE_FOR_MAKE}" > "${KERNEL_OUTPUT}"
>         fi
> @@ -219,18 +301,8 @@ kernel_do_configure() {
>                 cp "${WORKDIR}/defconfig" "${B}/.config"
>         fi
>         yes '' | oe_runmake oldconfig
> -
> -       if [ ! -z "${INITRAMFS_IMAGE}" ]; then
> -               for img in cpio.gz cpio.lzo cpio.lzma cpio.xz; do
> -               if [ -e "${DEPLOY_DIR_IMAGE}/${INITRAMFS_IMAGE}-${MACHINE}.$img" ]; then
> -                       cp "${DEPLOY_DIR_IMAGE}/${INITRAMFS_IMAGE}-${MACHINE}.$img" initramfs.$img
> -               fi
> -               done
> -       fi
>  }
>
> -do_configure[depends] += "${INITRAMFS_TASK}"
> -
>  do_savedefconfig() {
>         oe_runmake savedefconfig
>  }
> diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
> index 2b078d0..17733ab 100644
> --- a/meta/conf/local.conf.sample
> +++ b/meta/conf/local.conf.sample
> @@ -146,6 +146,26 @@ EXTRA_IMAGE_FEATURES = "debug-tweaks"
>  USER_CLASSES ?= "buildstats image-mklibs image-prelink"
>
>  #
> +# Kernel image features
> +#
> +# The INITRAMFS_IMAGE image variable will cause an additional recipe to
> +# be built as a dependency to the what ever rootfs recipe you might be
> +# using such as core-image-sato.  The initramfs might be needed for
> +# the initial boot of of the target system such as to load kernel
> +# modules prior to mounting the root file system.
> +#
> +# INITRAMFS_IMAGE_BUNDLE variable controls if the image recipe
> +# specified by the INITRAMFS_IMAGE will be run through an extra pass
> +# through the kernel compilation in order to build a single binary
> +# which contains both the kernel image and the initramfs.  The
> +# combined binary will be deposited into the tmp/deploy directory.
> +# NOTE: You can set INITRAMFS_IMAGE in an image recipe, but
> +#       INITRAMFS_IMAGE_BUNDLE can only be set in a conf file.
> +#
> +#INITRAMFS_IMAGE = "core-image-minimal-initramfs"
> +#INITRAMFS_IMAGE_BUNDLE = "1"
> +
> +#
>  # Runtime testing of images
>  #
>  # The build system can test booting virtual machine images under qemu (an emulator)
> --
> 1.7.9.5
>
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