Build arch kernel packages from local git kernel tree

PKGBUILD

# This will build Arch Linux binary and linux-headers packages from a git
# kernel tree in the current directory
# Derived from:
# https://github.com/archlinux/svntogit-packages/blob/packages/linux/trunk/PKGBUILD

_srcname="$PWD"

pkgbase=linux-tpc
pkgver=6.1.0
pkgrel=1
pkgdesc='Linux'
_srctag=v${pkgver%.*}-${pkgver##*.}
arch=(x86_64)
license=(GPL2)
makedepends=(
  bc libelf cpio perl tar xz
  git
)
options=('!strip')

export KBUILD_BUILD_HOST=archlinux
export KBUILD_BUILD_USER=$pkgbase
export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"

prepare() {
    cd $_srcname

    scripts/setlocalversion --save-scmversion
    echo "-tpc-$pkgrel" > localversion.10

    kernver="$(make -s kernelrelease)"
    echo "$kernver" > version
    echo "Prepared version $kernver"
}

build() {
    cd $_srcname
    make all -j$(nproc)
}

_package() {
    pkgdesc="The $pkgdesc kernel and modules"
    depends=(coreutils kmod initramfs)
    optdepends=('wireless-regdb: to set the correct wireless channels of your country'
              'linux-firmware: firmware images needed for some devices')
    provides=(VIRTUALBOX-GUEST-MODULES WIREGUARD-MODULE KSMBD-MODULE)
    replaces=(virtualbox-guest-modules-arch wireguard-arch)

    cd $_srcname
    local kernver="$(< version)"
    local modulesdir="$pkgdir/usr/lib/modules/$kernver"

    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"

    # 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 and source links
    rm "$modulesdir/"{source,build}
}

_package-headers() {
    pkgdesc="Headers and scripts for building modules for the $pkgdesc kernel"
    depends=(pahole)

    cd $_srcname
    local kernver="$(< version)"
    local builddir="$pkgdir/usr/lib/modules/$kernver/build"

    echo "Installing build files..."
    install -Dt "$builddir" -m644 .config Makefile Module.symvers System.map \
        localversion.* version vmlinux
    install -Dt "$builddir/kernel" -m644 kernel/Makefile
    install -Dt "$builddir/arch/x86" -m644 arch/x86/Makefile
    cp -t "$builddir" -a scripts

    # required when STACK_VALIDATION is enabled
    install -Dt "$builddir/tools/objtool" tools/objtool/objtool

    # required when DEBUG_INFO_BTF_MODULES is enabled
    ##install -Dt "$builddir/tools/bpf/resolve_btfids" tools/bpf/resolve_btfids/resolve_btfids

    echo "Installing headers..."
    cp -t "$builddir" -a include
    cp -t "$builddir/arch/x86" -a arch/x86/include
    install -Dt "$builddir/arch/x86/kernel" -m644 arch/x86/kernel/asm-offsets.s

    install -Dt "$builddir/drivers/md" -m644 drivers/md/*.h
    install -Dt "$builddir/net/mac80211" -m644 net/mac80211/*.h

    # https://bugs.archlinux.org/task/13146
    install -Dt "$builddir/drivers/media/i2c" -m644 drivers/media/i2c/msp3400-driver.h

    # https://bugs.archlinux.org/task/20402
    install -Dt "$builddir/drivers/media/usb/dvb-usb" -m644 drivers/media/usb/dvb-usb/*.h
    install -Dt "$builddir/drivers/media/dvb-frontends" -m644 drivers/media/dvb-frontends/*.h
    install -Dt "$builddir/drivers/media/tuners" -m644 drivers/media/tuners/*.h

    # https://bugs.archlinux.org/task/71392
    install -Dt "$builddir/drivers/iio/common/hid-sensors" -m644 drivers/iio/common/hid-sensors/*.h

    echo "Installing KConfig files..."
    find . -name 'Kconfig*' -exec install -Dm644 {} "$builddir/{}" \;

    echo "Removing unneeded architectures..."
    local arch
    for arch in "$builddir"/arch/*/; do
        [[ $arch = */x86/ ]] && continue
        echo "Removing $(basename "$arch")"
        rm -r "$arch"
    done

    echo "Removing documentation..."
    rm -r "$builddir/Documentation"

    echo "Removing broken symlinks..."
    find -L "$builddir" -type l -printf 'Removing %P\n' -delete

    echo "Removing loose objects..."
    find "$builddir" -type f -name '*.o' -printf 'Removing %P\n' -delete

    echo "Stripping build tools..."
    local file
    while read -rd '' file; do
        case "$(file -Sib "$file")" in
            application/x-sharedlib\;*)      # Libraries (.so)
                strip -v $STRIP_SHARED "$file" ;;
            application/x-archive\;*)        # Libraries (.a)
                strip -v $STRIP_STATIC "$file" ;;
            application/x-executable\;*)     # Binaries
                strip -v $STRIP_BINARIES "$file" ;;
            application/x-pie-executable\;*) # Relocatable binaries
                strip -v $STRIP_SHARED "$file" ;;
        esac
    done < <(find "$builddir" -type f -perm -u+x ! -name vmlinux -print0)

    echo "Stripping vmlinux..."
    strip -v $STRIP_STATIC "$builddir/vmlinux"

    echo "Adding symlink..."
    mkdir -p "$pkgdir/usr/src"
    ln -sr "$builddir" "$pkgdir/usr/src/$pkgbase"
}

pkgname=("$pkgbase" "$pkgbase-headers")
for _p in "${pkgname[@]}"; do
  eval "package_$_p() {
    $(declare -f "_package${_p#$pkgbase}")
    _package${_p#$pkgbase}
  }"
done

# vim:set ts=8 sts=2 sw=2 et: