Message-ID: <20240704182115.GA300903@thelio-3990X>
Date: Thu, 4 Jul 2024 11:21:15 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Thomas Weißschuh <linux@...ssschuh.net>
Cc: Masahiro Yamada <masahiroy@...nel.org>,
	Nicolas Schier <nicolas@...sle.eu>,
	"Jan Alexander Steffens (heftig)" <heftig@...hlinux.org>,
	linux-kernel@...r.kernel.org, linux-kbuild@...r.kernel.org
Subject: Re: [PATCH] kbuild: add script and target to generate pacman package

Hi Thomas,

On Thu, Jul 04, 2024 at 06:36:34PM +0200, Thomas Weißschuh wrote:
> pacman is the package manager used by Arch Linux and its derivates.
> Creating native packages from the kernel tree has multiple advantages:
> 
> * The package triggers the correct hooks for initramfs generation and
>   bootloader configuration
> * Uninstallation is complete and also invokes the relevant hooks
> * New UAPI headers can be installed without any manual bookkeeping
> 
> The PKGBUILD file is a simplified version of the one used for the
> downstream Arch Linux "linux" package.
> Extra steps that should not be necessary for a development kernel have
> been removed and an UAPI header package has been added.
> 
> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>

This is pretty awesome and much needed I think, it would allow me to
replace my own home grown "build an Arch Linux kernel package" script.
It should also make it much easier for users of Arch Linux and related
distributions to build and test mainline kernels for issue reproduction
and bisecting, which is one of the biggest hurdles I have encountered
when it comes to working with those users.

The resulting package that I get boots in my virtual machine (I can't
take down my workstation at the moment).

I notice one warning during the build phase that appears to come from makepkg
itself? The permissions of the pkg folder are execute only. This is building
using O=, I haven't had much time to look into it aside from that.

  $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 O=... olddefconfig pacman-pkg
  ==> Making package: linux-upstream 6.10.0_rc6_00051_g1dfe225e9af5_dirty-1 (Thu 04 Jul 2024 10:02:14 AM MST)
  ==> Checking runtime dependencies...
  ==> Checking buildtime dependencies...
  ==> Retrieving sources...
  ==> Extracting sources...
  ==> Starting build()...
  find: ‘./pacman/linux-upstream/pkg’: Permission denied
  ...

  $ ls -al .../pacman/linux-upstream
  total 16
  drwxr-xr-x 4 nathan nathan 4096 Jul  4 10:02 .
  drwxr-xr-x 3 nathan nathan 4096 Jul  4 10:02 ..
  d--x--x--x 2 nathan nathan 4096 Jul  4 10:02 pkg
  drwxr-xr-x 2 nathan nathan 4096 Jul  4 10:02 src

Not a big deal to me though, it's only a warning.

> ---
>  .gitignore               |  6 ++++
>  scripts/Makefile.package | 15 ++++++++++
>  scripts/package/PKGBUILD | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 93 insertions(+)
> 
> diff --git a/.gitignore b/.gitignore
> index c59dc60ba62e..7902adf4f7f1 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -92,6 +92,12 @@ modules.order
>  #
>  /tar-install/
>  
> +#
> +# pacman files (make pacman-pkg)
> +#
> +/PKGBUILD
> +/pacman/
> +
>  #
>  # We don't want to ignore the following even if they are dot-files
>  #
> diff --git a/scripts/Makefile.package b/scripts/Makefile.package
> index bf016af8bf8a..8c0c80f8bec0 100644
> --- a/scripts/Makefile.package
> +++ b/scripts/Makefile.package
> @@ -141,6 +141,20 @@ snap-pkg:
>  	cd $(objtree)/snap && \
>  	snapcraft --target-arch=$(UTS_MACHINE)
>  
> +# pacman-pkg
> +# ---------------------------------------------------------------------------
> +
> +PHONY += pacman-pkg
> +pacman-pkg:
> +	@ln -srf $(srctree)/scripts/package/PKGBUILD $(objtree)/PKGBUILD
> +	cd $(objtree) && \
> +		srctree="$(realpath $(srctree))" \
> +		objtree="$(realpath $(objtree))" \
> +		BUILDDIR="$(realpath $(objtree))/pacman" \
> +		KBUILD_MAKEFLAGS="$(MAKEFLAGS)" \
> +		KBUILD_REVISION="$(shell $(srctree)/init/build-version)" \
> +		makepkg
> +
>  # dir-pkg tar*-pkg - tarball targets
>  # ---------------------------------------------------------------------------
>  
> @@ -221,6 +235,7 @@ help:
>  	@echo '  bindeb-pkg          - Build only the binary kernel deb package'
>  	@echo '  snap-pkg            - Build only the binary kernel snap package'
>  	@echo '                        (will connect to external hosts)'
> +	@echo '  pacman-pkg          - Build only the binary kernel pacman package'
>  	@echo '  dir-pkg             - Build the kernel as a plain directory structure'
>  	@echo '  tar-pkg             - Build the kernel as an uncompressed tarball'
>  	@echo '  targz-pkg           - Build the kernel as a gzip compressed tarball'
> diff --git a/scripts/package/PKGBUILD b/scripts/package/PKGBUILD
> new file mode 100644
> index 000000000000..29daf357edc1
> --- /dev/null
> +++ b/scripts/package/PKGBUILD
> @@ -0,0 +1,72 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +# Contributor: Jan Alexander Steffens (heftig) <heftig@...hlinux.org>
> +# Maintainer: Thomas Weißschuh <linux@...ssschuh.net>
> +
> +pkgbase=linux-upstream
> +pkgname=("$pkgbase" "$pkgbase-headers" "$pkgbase-api-headers")
> +pkgver="${KERNELRELEASE//-/_}"
> +pkgrel="$KBUILD_REVISION"
> +pkgdesc='Linux'
> +url='https://www.kernel.org/'
> +arch=("$UTS_MACHINE")
> +options=(!strip)
> +license=(GPL-2.0-only)
> +
> +build() {
> +  export MAKEFLAGS="${KBUILD_MAKEFLAGS}"
> +  cd "$objtree"
> +
> +  ${MAKE} -f "${srctree}/Makefile"
> +
> +}
> +
> +package_linux-upstream() {
> +  pkgdesc="The $pkgdesc kernel and modules"
> +
> +  export MAKEFLAGS="${KBUILD_MAKEFLAGS}"
> +  cd "$objtree"
> +  local modulesdir="$pkgdir/usr/$MODLIB"
> +
> +  echo "Installing boot image..."
> +  # systemd expects to find the kernel here to allow hibernation
> +  # https://github.com/systemd/systemd/commit/edda44605f06a41fb86b7ab8128dcf99161d2344
> +  install -Dm644 "$(make -s image_name)" "$modulesdir/vmlinuz"

should this be ${MAKE}? I suppose it does not really matter much.

Would it be worth copying the .config and System.map to $modulesdir like
kernel.spec here as well? I know that upstream does not do this, as it
enables IKCONFIG in /proc but it would be potentially useful in certain
scenarios.

One other minor suggestion would be installing the dtbs somewhere if
the architecture supports them, maybe to $modulesdir/dtbs? Not super
critical but I know Arch Linux Ports is gaining traction, so it might be
good to future proof this a little bit.

> +  # Used by mkinitcpio to name the kernel
> +  echo "$pkgbase" | install -Dm644 /dev/stdin "$modulesdir/pkgbase"
> +
> +  echo "Installing modules..."
> +  ${MAKE} INSTALL_MOD_PATH="$pkgdir/usr" INSTALL_MOD_STRIP=1 \
> +    DEPMOD=/doesnt/exist modules_install  # Suppress depmod
> +
> +  # remove build link

Perhaps it is worth mentioning that this is done because it will be
created again/properly in the headers package?

> +  rm -f "$modulesdir/build"
> +}
> +
> +package_linux-upstream-headers() {
> +  pkgdesc="Headers and scripts for building modules for the $pkgdesc kernel"
> +
> +  export MAKEFLAGS="${KBUILD_MAKEFLAGS}"
> +  cd "$objtree"
> +  local builddir="$pkgdir/usr/$MODLIB/build"
> +
> +  echo "Installing build files..."
> +  "$srctree/scripts/package/install-extmod-build" "$builddir"
> +
> +  echo "Adding symlink..."
> +  mkdir -p "$pkgdir/usr/src"
> +  ln -sr "$builddir" "$pkgdir/usr/src/$pkgbase"
> +}
> +
> +package_linux-upstream-api-headers() {
> +  pkgdesc="Kernel headers sanitized for use in userspace"
> +  provides=(linux-api-headers)
> +  conflicts=(linux-api-headers)
> +
> +  export MAKEFLAGS="${KBUILD_MAKEFLAGS}"
> +  cd "$objtree"
> +
> +  ${MAKE} headers_install INSTALL_HDR_PATH="$pkgdir/usr"
> +}
> +
> +# vim:set ts=8 sts=2 sw=2 et:
> 
> ---
> base-commit: 795c58e4c7fc6163d8fb9f2baa86cfe898fa4b19
> change-id: 20240625-kbuild-pacman-pkg-b4f87e19d036
> 
> Best regards,
> -- 
> Thomas Weißschuh <linux@...ssschuh.net>
> 

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