Re: [PATCH L-C v2 7/7] linux-custom: rewrite to no longer depend on the kernel's builddeb

[Jan Kiszka <jan.kiszka@siemens.com>]

On 09.11.19 14:43, Cedric Hombourger wrote:
> 
> 
> On Sat, 9 Nov 2019 at 09:51, Jan Kiszka <jan.kiszka@siemens.com 
> <mailto:jan.kiszka@siemens.com>> wrote:
> 
>     On 07.11.19 10:23, Cedric Hombourger wrote:
>      > Regain control over the packaging of the Linux kernel by
>     providing our
>      > own debian recipes (debian,{control,rules} files and friends) instead
>      > of using the kernel's builddeb script. This will allow generation of
>      > packages for "perf" (not included in this changeset) with per distro
>      > scheme (Debian and Ubuntu have differences) and maintain
>     compatibility
>      > with upstream packages generated from different source packages but
>      > dependent on a certain deployment scheme (e.g. linux-base for Debian)
>      >
>      > Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com
>     <mailto:Cedric_Hombourger@mentor.com>>
>      > ---
>      >   doc/custom_kernel.md                          | 181
>     ++++++++++++++++
>      >   .../linux/files/build-kernel.sh               | 128 -----------
>      >   meta/recipes-kernel/linux/files/debian/compat |   1 +
>      >   .../linux/files/debian/control.tmpl           |  37 ++++
>      >   .../linux/files/debian/isar/build.tmpl        |  36 ++++
>      >   .../linux/files/debian/isar/clean.tmpl        |  20 ++
>      >   .../linux/files/debian/isar/common.tmpl       |  48 +++++
>      >   .../linux/files/debian/isar/install.tmpl      | 204
>     ++++++++++++++++++
>      >   .../files/debian/linux-image.postinst.tmpl    |  29 +++
>      >   .../files/debian/linux-image.postrm.tmpl      |  35 +++
>      >   .../files/debian/linux-image.preinst.tmpl     |  25 +++
>      >   .../linux/files/debian/linux-image.prerm.tmpl |  21 ++
>      >   .../linux/files/debian/rules.tmpl             |  41 ++++
>      >   meta/recipes-kernel/linux/linux-custom.inc    | 179 ++++++++++-----
>      >   14 files changed, 800 insertions(+), 185 deletions(-)
>      >   create mode 100644 doc/custom_kernel.md
>      >   delete mode 100644 meta/recipes-kernel/linux/files/build-kernel.sh
>      >   create mode 100644 meta/recipes-kernel/linux/files/debian/compat
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/control.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/isar/build.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/isar/clean.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/isar/common.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/isar/install.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/linux-image.postinst.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/linux-image.postrm.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/linux-image.preinst.tmpl
>      >   create mode 100644
>     meta/recipes-kernel/linux/files/debian/linux-image.prerm.tmpl
>      >   create mode 100755
>     meta/recipes-kernel/linux/files/debian/rules.tmpl
>      >
>      > diff --git a/doc/custom_kernel.md b/doc/custom_kernel.md
>      > new file mode 100644
>      > index 0000000..934325a
>      > --- /dev/null
>      > +++ b/doc/custom_kernel.md
>      > @@ -0,0 +1,181 @@
>      > +# Custom kernel recipe for Isar
>      > +
>      > +## Contents
>      > +
>      > + - [Summary](#summary)
>      > + - [Proposal owners](#proposal-owners)
>      > + - [Current status](#current-status)
>      > + - [Detailed description](#detailed-description)
>      > + - [Benefit to Isar](#benefit-to-isar)
>      > + - [How can I help?](#how-can-i-help)
>      > + - [Scope](#scope)
>      > + - [How to test](#how-to-test)
>      > + - [Dependencies](#dependencies)
>      > + - [Documentation](#documentation)
>      > + - [Questions and answers](#questions-and-answers)
>      > +
>      > +## Summary
>      > +
>      > +Isar currently uses the Linux kernel's builddeb script to
>     generate linux-image,
>      > +linux-headers and linux-libc-dev packages for your custom kernel
>     sources. The
>      > +main benefit of this approach was that the low level details of
>     how to package
>      > +the Linux kernel image, modules and headers were left in the
>     kernel. There are
>      > +however some drawbacks: Isar had to repack generated packages to
>     introduce some
>      > +of the changes it needs such as suffixing the kernel packages
>     with the name of
>      > +the custom kernel (e.g. with "mainline" for the "linux-mainline"
>     recipe), lack
>      > +of automatic dependencies (the builddeb script from the kernel
>     does not use
>      > +debhelper), it was difficult to add packages especially
>     distribution specific
>      > +packages (maintain version specific patch in Isar vs being able
>     to upstream
>      > +distribution specific changes upstream), etc. This change is
>     about being less
>      > +dependent on the kernel packaging scripts (which aren't used by
>     major distros
>      > +anyway) and regain control on how we want or need the Linux
>     kernel packaged.
>      > +
>      > +## Proposal owners
>      > +
>      > + * name: [Cedric Hombourger](https://github.com/chombourger)
>      > +
>      > +## Current status
>      > +
>      > +### Tests
>      > +
>      > +The following were recently checked:
>      > +
>      > + * Custom kernels in meta-isar build without (known) failures
>      > + * initrd image gets generated when the kernel is added to the
>     rootfs
>      > + * `ISAR_CROSS_COMPILE` is supported
>      > + * `KERNEL_FILE` is honored
>      > + * `KERNEL_DEFCONFIG` may either be a file (specified via
>     `SRC_URI`) or a
>      > +   kernel-provided defconfig
>      > + * Config fragments get merged with the user-specified kernel
>     configuration
>      > + * Path to installed DTBs may be configured (new)
>      > + * Configuration and build from a `devshell`
>      > + * Support for the `KERNEL_LIBC_DEV_DEPLOY` directive
>      > +
>      > +while the following needs work:
>      > +
>      > + * Check if custom-kernel builds are reproducible
>      > +
>      > +### Remaining work items
>      > +
>      > + * Check if there is a better way to cross compile kernel
>     "scripts" such as
>      > +   `fixdep` or `modpost` than manually compiling them (they are
>     compiled for
>      > +   the build machine (amd64) and not for the target (e.g. armhf)
>     even though
>      > +   we are cross-compiling - yet the linux-headers package should
>     be shipping
>      > +   "scripts" for the target machine)
>      > +
>      > +## Detailed description
>      > +
>      > +### Requirements
>      > +
>      > +#### Current
>      > +
>      > +Isar has had a `linux-custom` recipe for a long time and counts
>     many users. It is therefore
>      > +paramount to maintain features that it has today with no or
>     little changes to the APIs. The
>      > +following requirements were identified and will be maintained:
>      > +
>      > + 1. Sources to the custom Linux kernel may be specified via
>     `SRC_URI`
>      > +
>      > + 2. Configure the kernel via an in-tree or an external
>     `defconfig` via `KERNEL_DEFCONFIG`
>      > +
>      > + 3. Support kernel configuration tweaks via configuration
>     fragments (`.cfg` files)
>      > +
>      > + 4. Patches to the linux kernel may be specified via `SRC_URI`
>      > +
>      > + 5. Ensure that the Isar recipe `PV` matches the kernel release
>     identifier (`KERNEL_RELEASE`)
>      > +
>      > + 6. Produce a `linux-image` package that ships the kernel image
>     and modules
>      > +
>      > + 7. Allow the name of the kernel image to be changed via
>     `KERNEL_FILE` (defaults to `vmlinuz`)
>      > +
>      > + 8. Produce a `linux-headers` package which includes kernel
>     headers and kbuild scripts/tools
>      > +
>      > + 9. The `linux-headers` package shall support native and cross
>     compiles of out-of-tree kernel modules
>      > +
>      > + 10. Produce a `linux-libc-dev` package to support user-land builds
>      > +
>      > + 11. Only ship the `linux-libc-dev` package if instructed to
>     (`KERNEL_LIBC_DEV_DEPLOY` equals to `"1"`)
>      > +
>      > + 12. Support both native and cross compiles (`ISAR_CROSS_COMPILE`)
>      > +
>      > + 13. Support for the following kernel architectures:
>      > +
>      > +   * arm
>      > +   * arm64
>      > +   * mips
>      > +   * x86
>      > +
>      > + 14. Support `devshell` (kernel configuration shall be applied)
>      > +
>      > +#### New requirements (proposed)
>      > +
>      > +This proposal includes the following new requirements:
>      > +
>      > + 1. Support creation of additional packages
>      > +
>      > + 2. Allow per-distro packaging tweaks
>      > +
>      > +### Approach
>      > +
>      > +The new implementation will have the `builddeb` code ported from
>     the Linux kernel included to the
>      > +Isar environment. It will be refactor to support pre and post
>     hooks. Hooks may be used by external
>      > +layers to extend the kernel packaging instructions provided by
>     "stock" Isar or by Isar itself to
>      > +implement distro-specific packages or tweaks.
>      > +
>      > +Hooks need the ability to add `build` and `install` steps which
>     can be achieved by having the main
>      > +`build` and `install` steps call pre and post scripts. This will
>     however solve only one side of the
>      > +problem: new packages should be declared in the `debian/control`
>     file. The packaging process
>      > +(initiated by `debian/rules`) will use a baseline `control` file
>     when started and a mechanism will
>      > +be provided for hooks to append `control` blocks as they are
>     processed.
>      > +
>      > +### Future work
>      > +
>      > +In the event where this proposal is accepted, here are a few
>     future projects that are being
>      > +considered:
>      > +
>      > + 1. Package `perf` as Debian does
>      > +
>      > + 2. Add `ubuntu` as an Isar supported target distro and validate
>     `linux-custom` recipe
>      > +
>      > +## Benefit to Isar
>      > +
>      > + * Control the kernel build and packaging process
>      > +
>      > + * No longer need to repack packages
>      > +
>      > + * Provide hooks for custom kernel recipes to add build/install
>     directives
>      > +
>      > +## How can I help?
>      > +
>      > + * Check if you are able to build your own linux-custom recipes
>     with this change
>      > + * Check if packages generated by this recipe are compatible
>     with your Debian-based distro
>      > + * Review and provide comments on this changeset
>      > + * Create templates for distro-specific packages (e.g. perf)
>      > +
>      > +## Scope
>      > +
>      > + * Proposal owners: proposal owners are to communicate the idea
>     to isar-users and make sure
>      > +   that all of their requirements are met (to the extent they
>     are already supported with the
>      > +   current solution) or may be met in the future.
>      > +
>      > + * Other developers: port your out-of-tree linux-custom recipes
>     to this new solution and
>      > +   report issues.
>      > +
>      > +## How to test?
>      > +
>      > +The linux-mainline recipe may be used for some basic testing.
>     This recipe is being used by the
>      > +following machines:
>      > +
>      > + * de0-nano-soc
>      > + * qemumipsel
>      > +
>      > +## Dependencies
>      > +
>      > + * None
>      > +
>      > +## Documentation
>      > +
>      > + * Document user-visible variables added by this proposal
>      > +
>      > +## Questions and answers
>      > +
>      > + * None
>      > diff --git a/meta/recipes-kernel/linux/files/build-kernel.sh
>     b/meta/recipes-kernel/linux/files/build-kernel.sh
>      > deleted file mode 100644
>      > index f56e96c..0000000
>      > --- a/meta/recipes-kernel/linux/files/build-kernel.sh
>      > +++ /dev/null
>      > @@ -1,128 +0,0 @@
>      > -#!/bin/bash
>      > -#
>      > -# Custom kernel build
>      > -#
>      > -# This software is a part of ISAR.
>      > -# Copyright (c) Siemens AG, 2018
>      > -#
>      > -# SPDX-License-Identifier: MIT
>      > -
>      > -source /isar/common.sh
>      > -
>      > -host_arch=$(dpkg --print-architecture)
>      > -
>      > -if [ "$host_arch" != "$target_arch" ]; then
>      > -    case $target_arch in
>      > -    armhf)
>      > -        export ARCH=arm
>      > -        export CROSS_COMPILE="arm-linux-gnueabihf-"
>      > -        ;;
>      > -    arm64)
>      > -        export ARCH=arm64
>      > -        export CROSS_COMPILE="aarch64-linux-gnu-"
>      > -        ;;
>      > -    mipsel)
>      > -        export ARCH=mips
>      > -        export CROSS_COMPILE="mipsel-linux-gnu-"
>      > -        ;;
>      > -    *)
>      > -        echo "error: unsupported architecture ($target_arch)"
>      > -        exit 1
>      > -        ;;
>      > -    esac
>      > -fi
>      > -
>      > -REPACK_DIR="$1/../repack"
>      > -REPACK_LINUX_IMAGE_DIR="${REPACK_DIR}/linux-image"
>      > -REPACK_LINUX_HEADERS_DIR="${REPACK_DIR}/linux-headers"
>      > -
>      > -make ${KERNEL_CONFIG_TARGET} || exit ${?}
>      > -if [ -n "${KERNEL_FRAGMENTS}" ]; then
>      > -    scripts/kconfig/merge_config.sh -m .config ${KERNEL_FRAGMENTS}
>      > -fi
>      > -
>      > -KV=$( make -s kernelrelease )
>      > -if [ "${KV}" != "${PV}" ]; then
>      > -     echo "ERROR: Recipe PV is \"${PV}\" but should be
>     \"${KV}\"" 1>&2
>      > -     echo "ERROR: Probably due to CONFIG_LOCALVERSION" 1>&2
>      > -     exit 1
>      > -fi
>      > -
>      > -rm -f .version
>      > -KBUILD_DEBARCH=$target_arch make -j $(($(nproc) * 2)) deb-pkg
>      > -
>      > -rm -rf "${REPACK_DIR}"
>      > -mkdir -p "${REPACK_DIR}"
>      > -mkdir -p "${REPACK_LINUX_IMAGE_DIR}"
>      > -mkdir -p "${REPACK_LINUX_HEADERS_DIR}"
>      > -
>      > -cp -a debian "${REPACK_DIR}"
>      > -
>      > -# dpkg-gencontrol performs cross-incompatible checks on the
>      > -# Architecture field; trick it to accept the control file
>      > -sed -i "s/Architecture: .*/Architecture: any/"
>     "${REPACK_DIR}/debian/control"
>      > -
>      > -cd ..
>      > -
>      > -dpkg-deb -R linux-image-${PV}_${PV}-1_*.deb
>     "${REPACK_LINUX_IMAGE_DIR}"
>      > -dpkg-deb -R linux-headers-${PV}_${PV}-1_*.deb
>     "${REPACK_LINUX_HEADERS_DIR}"
>      > -
>      > -dpkg-gencontrol -crepack/debian/control \
>      > -     -lrepack/debian/changelog \
>      > -     -frepack/debian/files \
>      > -     -plinux-image-${PV} \
>      > -     -P"${REPACK_LINUX_IMAGE_DIR}" \
>      > -     -DPackage="linux-image-${KERNEL_NAME}" \
>      > -     -DSection=kernel \
>      > -     -DPriority=required \
>      > -     -DDepends="${KERNEL_DEBIAN_DEPENDS}" \
>      > -     -DArchitecture=$target_arch
>      > -
>      > -# Add Debian-like link installation to postinst
>      > -mkdir -p ${REPACK_LINUX_IMAGE_DIR}/lib/modules/${PV}
>      > -touch "${REPACK_LINUX_IMAGE_DIR}/lib/modules/${PV}/.fresh-install"
>      > -sed -i "${REPACK_LINUX_IMAGE_DIR}/DEBIAN/postinst" \
>      > -    -e "/^set -e$/a\\
>      > -\\
>      > -if [ -f /lib/modules/${PV}/.fresh-install ]; then\\
>      > -     change=install\\
>      > -else\\
>      > -     change=upgrade\\
>      > -fi\\
>      > -linux-update-symlinks \$change ${PV} /boot/${KERNEL_FILE}-${PV}\\
>      > -rm -f /lib/modules/${PV}/.fresh-install"
>      > -
>      > -# Add Debian-like link removal to postrm
>      > -sed -i "${REPACK_LINUX_IMAGE_DIR}/DEBIAN/postrm" \
>      > -    -e "/^set -e$/a\\
>      > -\\
>      > -rm -f /lib/modules/${PV}/.fresh-install\\
>      > -\\
>      > -if [ \"\$1\" != upgrade ] && command -v linux-update-symlinks
>      >/dev/null; then\\
>      > -     linux-update-symlinks remove ${PV} 
>     /boot/${KERNEL_FILE}-${PV}\\
>      > -fi"
>      > -
>      > -# Make sure arm64 kernels are decompressed
>      > -if [ "$target_arch" = "arm64" ]; then
>      > -   
>       kernel_file="${REPACK_LINUX_IMAGE_DIR}/boot/${KERNEL_FILE}-${PV}"
>      > -     mv "${kernel_file}" "${kernel_file}.gz"
>      > -     gunzip "${kernel_file}.gz"
>      > -fi
> 
>     Next regression: This got lost.
> 
> 
> Fixed locally 
> (https://github.com/chombourger/isar-fork/blob/cedric/next/meta/recipes-kernel/linux/files/debian/isar/install.tmpl#L62)
> Started a test build to check
> 
> Thanks for catching that subtle one
> 

Do you plan to send a v4 soon? I'm playing with the "final" fix for 
patch.bbclass (i.e. an OE-core import), and that clashes with the 
current kernel build. Before patching that again...

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux