--- /dev/null
+# Copyright 2019 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+inherit mount-boot savedconfig toolchain-funcs
+
+MY_P=linux-${PV}
+CONFIG_VER=5.4.4.arch1-1
+CONFIG_HASH=f101331956bb37080dce191ca789a5c44fac9e69
+
+DESCRIPTION="Linux kernel built from vanilla upstream sources"
+HOMEPAGE="https://www.kernel.org/"
+SRC_URI="https://cdn.kernel.org/pub/linux/kernel/v5.x/${MY_P}.tar.xz
+ https://git.archlinux.org/svntogit/packages.git/plain/trunk/config?h=packages/linux&id=${CONFIG_HASH}
+ -> linux-${CONFIG_VER}.config"
+S=${WORKDIR}/${MY_P}
+
+LICENSE="GPL-2"
+SLOT="${PV}"
+KEYWORDS="~amd64"
+IUSE="+initramfs"
+
+# install-DEPEND actually
+# note: we need installkernel with initramfs support!
+RDEPEND="
+ || (
+ sys-kernel/installkernel-gentoo
+ sys-kernel/installkernel-systemd-boot
+ )
+ initramfs? ( sys-kernel/dracut )"
+
+pkg_pretend() {
+ mount-boot_pkg_pretend
+
+ ewarn "This is an experimental package. The built kernel and/or initramfs"
+ ewarn "may not work at all or fail with your bootloader configuration. Please"
+ ewarn "make sure to keep a backup kernel available before testing it."
+}
+
+src_configure() {
+ # force ld.bfd if we can find it easily
+ local LD="$(tc-getLD)"
+ if type -P "${LD}.bfd" &>/dev/null; then
+ LD+=.bfd
+ fi
+
+ MAKEARGS=(
+ V=1
+
+ HOSTCC="$(tc-getCC)"
+ HOSTCXX="$(tc-getCXX)"
+ HOSTCFLAGS="${CFLAGS}"
+ HOSTLDFLAGS="${LDFLAGS}"
+
+ AS="$(tc-getAS)"
+ CC="$(tc-getCC)"
+ LD="${LD}"
+ AR="$(tc-getAR)"
+ NM="$(tc-getNM)"
+ STRIP=":"
+ OBJCOPY="$(tc-getOBJCOPY)"
+ OBJDUMP="$(tc-getOBJDUMP)"
+
+ # we need to pass it to override colliding Gentoo envvar
+ ARCH=x86
+ )
+
+ cp "${DISTDIR}"/linux-${CONFIG_VER}.config .config || die
+ # while Arch config is cool, we don't want gcc plugins as they
+ # break distcc
+ sed -i -e '/GCC_PLUGIN/d' .config || die
+ # module compression prevents us from stripping them post-inst
+ sed -i -e '/MODULE_COMPRESS/d' .config || die
+ # shove our theft under the carpet!
+ sed -i -e '/HOSTNAME/s:archlinux:gentoo:' .config || die
+ restore_config .config
+
+ mkdir -p "${WORKDIR}"/modprep || die
+ mv .config "${WORKDIR}"/modprep/ || die
+ emake O="${WORKDIR}"/modprep "${MAKEARGS[@]}" olddefconfig
+ emake O="${WORKDIR}"/modprep "${MAKEARGS[@]}" modules_prepare
+ cp -pR "${WORKDIR}"/modprep "${WORKDIR}"/build || die
+}
+
+src_compile() {
+ emake O="${WORKDIR}"/build "${MAKEARGS[@]}" all
+}
+
+src_test() {
+ :
+}
+
+src_install() {
+ # do not use 'make install' as it behaves differently based
+ # on what kind of installkernel is installed
+ emake O="${WORKDIR}"/build "${MAKEARGS[@]}" \
+ INSTALL_MOD_PATH="${ED}" modules_install
+
+ # install headers and prepared objects on top of them
+ # note: we're using mv rather than doins to save space and time
+ find -name '*.c' -delete || die
+ rm -r Documentation || die
+ dodir /usr/src
+ cd "${WORKDIR}" || die
+ mv "${S}" "${ED}"/usr/src/ || die
+ # strip out-of-source build stuffs from modprep
+ find modprep -type f '(' \
+ -name Makefile -o \
+ -name '*.[ao]' -o \
+ '(' -name '.*' -a -not -name '.config' ')' \
+ ')' -delete || die
+ rm modprep/source || die
+ cp -pR modprep/. "${ED}/usr/src/linux-${PV}"/ || die
+
+ # install the kernel and files needed for module builds
+ cp build/{arch/x86/boot/bzImage,System.map,Module.symvers} \
+ "${ED}/usr/src/linux-${PV}"/ || die
+
+ # fix source tree and build dir symlinks
+ dosym ../../../usr/src/linux-${PV} /lib/modules/${PV}/build
+ dosym ../../../usr/src/linux-${PV} /lib/modules/${PV}/source
+
+ save_config build/.config
+}
+
+pkg_preinst() {
+ :
+}
+
+pkg_postinst() {
+ if [[ -z ${ROOT} ]]; then
+ mount-boot_pkg_preinst
+
+ local fail=
+
+ if use initramfs; then
+ ebegin "Building initramfs via dracut"
+ # putting it alongside kernel image as 'initrd' makes
+ # kernel-install happier
+ dracut --force "${EROOT}/usr/src/linux-${PV}/initrd" "${PV}"
+ eend || die "Building initramfs failed"
+ fi
+
+ ebegin "Installing the kernel via installkernel"
+ # note: .config is taken relatively to System.map;
+ # initrd relatively to bzImage
+ installkernel "${PV}" \
+ "${EROOT}/usr/src/linux-${PV}/bzImage" \
+ "${EROOT}/usr/src/linux-${PV}/System.map"
+ eend || fail=1
+
+ [[ ${fail} ]] && die "Installing the kernel failed"
+ fi
+
+ local symlink_target=$(readlink "${EROOT}"/usr/src/linux)
+ if [[ ${symlink_target} == linux-[0-9]* ]]; then
+ local symlink_ver=${symlink_target#linux-}
+ local symlink_pkg=${CATEGORY}/${PN}-${symlink_ver}
+ # if the current target is either being replaced, or still
+ # installed (probably depclean candidate), update the symlink
+ if has "${symlink_ver}" ${REPLACING_VERSIONS} ||
+ has_version -r "~${symlink_pkg}"
+ then
+ ebegin "Updating /usr/src/linux symlink"
+ ln -f -n -s linux-${PV} "${EROOT}"/usr/src/linux
+ eend
+ fi
+ fi
+
+ savedconfig_pkg_postinst
+}
+
+pkg_prerm() {
+ :
+}
+
+pkg_postrm() {
+ rm -f "${EROOT}/usr/src/linux-${PV}/initrd" &&
+ rmdir --ignore-fail-on-non-empty "${EROOT}/usr/src/linux-${PV}"
+}