# Maintainer: Gabor Pali <pali.gabor@gmail.com>

pkgname=linux-lts
pkgver=5.15.36
case $pkgver in
	*.*.*)	_kernver=${pkgver%.*};;
	*.*) _kernver=$pkgver;;
esac
pkgrel=0
pkgdesc="Linux LTS kernel"
url="https://www.kernel.org"
depends=
_depends_dev="perl gmp-dev mpc1-dev mpfr-dev elfutils-dev bash flex bison zstd"
makedepends="$_depends_dev perl flex bison elfutils-dev sed installkernel bc linux-headers linux-firmware-any openssl1.1-compat-dev diffutils findutils zstd xz"
options="!strip"
install=
source="https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/linux-$_kernver.tar.xz
	config-lts.x86_64
	"
subpackages="$pkgname-dev:_dev:$CBUILD_ARCH"

if [ "${pkgver%.0}" = "$pkgver" ]; then
	source="$source
	https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/patch-$pkgver.xz"
fi

arch="x86_64"
license="GPL-2.0"

prepare() {
	local _patch_failed=
	cd "$srcdir"/linux-$_kernver
	if [ "$_kernver" != "$pkgver" ]; then
		msg "Applying patch-$pkgver.xz"
		unxz -c < "$srcdir"/patch-$pkgver.xz | patch -p1 -N
	fi

	# first apply patches in specified order
	for i in $source; do
		case $i in
		*.patch)
			msg "Applying $i..."
			if ! patch -s -p1 -N -i "$srcdir"/$i; then
				echo $i >>failed
				_patch_failed=1
			fi
			;;
		esac
	done

	if ! [ -z "$_patch_failed" ]; then
		error "The following patches failed:"
		cat failed
		return 1
	fi

	# remove localversion from patch if any
	rm -f localversion*
	oldconfig
}

oldconfig() {
	local _config=config-lts.x86_64
	local _builddir="$srcdir"/build-lts.x86_64
	mkdir -p "$_builddir"
	echo "-$pkgrel-lts" > "$_builddir"/localversion-alpine \
		|| return 1

	cp "$srcdir"/$_config "$_builddir"/.config
	make -C "$srcdir"/linux-$_kernver \
		O="$_builddir" \
		ARCH="x86_64" \
		listnewconfig oldconfig
}

build() {
	unset LDFLAGS
	export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"
	cd "$srcdir"/build-lts.x86_64
	make ARCH="x86_64" CC="${CC:-gcc}" \
		KBUILD_BUILD_VERSION="$((pkgrel + 1 ))-Alpine"
}

package() {
	local _outdir="$pkgdir"
	local _abi_release=${pkgver}-${pkgrel}-lts
	export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"

	cd "$srcdir"/build-lts.x86_64
	# modules_install seems to regenerate a defect Modules.symvers on s390x. Work
	# around it by backing it up and restore it after modules_install
	cp Module.symvers Module.symvers.backup

	mkdir -p "$_outdir"/boot "$_outdir"/lib/modules

	make -j1 modules_install install \
		ARCH="x86_64" \
		INSTALL_MOD_PATH="$_outdir" \
		INSTALL_PATH="$_outdir"/boot \
		INSTALL_DTBS_PATH="$_outdir/boot/dtbs-lts"

	cp Module.symvers.backup Module.symvers

	rm -f "$_outdir"/lib/modules/${_abi_release}/build \
		"$_outdir"/lib/modules/${_abi_release}/source \
		"$_outdir"/boot/System.map-lts \
		"$_outdir"/boot/config-lts
	rm -rf "$_outdir"/lib/firmware
}

_dev() {
	local _abi_release=${pkgver}-${pkgrel}-lts
	# copy the only the parts that we really need for build 3rd party
	# kernel modules and install those as /usr/src/linux-headers,
	# simlar to what ubuntu does
	#
	# this way you dont need to install the 300-400 kernel sources to
	# build a tiny kernel module
	#
	pkgdesc="Headers and script for third party modules for lts kernel"
	depends="$_depends_dev"
	local dir="$subpkgdir"/usr/src/linux-headers-${_abi_release}
	export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"

	# first we import config, run prepare to set up for building
	# external modules, and create the scripts
	mkdir -p "$dir"
	cp "$srcdir"/config-lts.x86_64 "$dir"/.config
	echo "-$pkgrel-lts" > "$dir"/localversion-alpine

	make -j1 -C "$srcdir"/linux-$_kernver O="$dir" ARCH="x86_64" \
		syncconfig prepare modules_prepare scripts

	# remove the stuff that points to real sources. we want 3rd party
	# modules to believe this is the soruces
	rm "$dir"/Makefile "$dir"/source

	# copy the needed stuff from real sources
	#
	# this is taken from ubuntu kernel build script
	# http://kernel.ubuntu.com/git/ubuntu/ubuntu-zesty.git/tree/debian/rules.d/3-binary-indep.mk
	cd "$srcdir"/linux-$_kernver
	find .  -path './include/*' -prune \
		-o -path './scripts/*' -prune -o -type f \
		\( -name 'Makefile*' -o -name 'Kconfig*' -o -name 'Kbuild*' -o \
		   -name '*.sh' -o -name '*.pl' -o -name '*.lds' -o -name 'Platform' \) \
		-print | cpio -pdm "$dir"

	cp -a scripts include "$dir"

	find $(find arch -name include -type d -print) -type f \
		| cpio -pdm "$dir"

	install -Dm644 "$srcdir"/build-lts.$CARCH/Module.symvers \
		"$dir"/Module.symvers

	mkdir -p "$subpkgdir"/lib/modules/${_abi_release}
	ln -sf /usr/src/linux-headers-${_abi_release} \
		"$subpkgdir"/lib/modules/${_abi_release}/build
}

sha512sums="
d25ad40b5bcd6a4c6042fd0fd84e196e7a58024734c3e9a484fd0d5d54a0c1d87db8a3c784eff55e43b6f021709dc685eb0efa18d2aec327e4f88a79f405705a  linux-5.15.tar.xz
707daa3a56186daac44478e746a883f65d8b198ccedc2f32febaf9302482685270bde9695786a14914020925197f6d952530cd5753a709731f183ad32303b099  config-lts.x86_64
e4ff344c62a99bc48a69b3c241eed15288a20476ee89030b961d0bf09dad7762f18831b12abdc445a3346c6367c132ca30420e8f7d1b813fe857fcf96e6e49ae  patch-5.15.36.xz
"