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

pkgname=linux-lts
pkgver=6.1.54
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 sed installkernel bc linux-headers linux-firmware-any openssl-dev>3 mawk
	diffutils findutils zstd pahole>=1.25 python3"
options="!strip"
install=
source="https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/linux-$_kernver.tar.xz
	awk.patch
	config-lts.x86_64
	"
subpackages="$pkgname-dev:_dev:$CBUILD_ARCH"
builddir="$srcdir"/linux-"$_kernver"

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-only"

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

	default_prepare

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

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

	cp "$srcdir"/"$_config" "$_builddir"/.config
	msg "Configuring the kernel"
	make -C "$srcdir"/linux-"$_kernver" \
		O="$_builddir" \
		ARCH=x86_64 \
		olddefconfig
}

build() {
	unset LDFLAGS
	# for some reason these sometimes leak into the kernel build,
	# -Werror=format-security breaks some stuff
	unset CFLAGS CPPFLAGS CXXFLAGS
	export KBUILD_BUILD_TIMESTAMP="$(date -Ru${SOURCE_DATE_EPOCH:+d @$SOURCE_DATE_EPOCH})"
	_prepareconfig
	msg "Building the kernel"
	cd "$srcdir"/build-lts.x86_64
	make ARCH="x86_64" \
		CC="${CC:-gcc}" \
		AWK="${AWK:-mawk}" \
		KBUILD_BUILD_VERSION="$((pkgrel + 1 ))-Alpine"
}

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

	cd "$srcdir"/build-lts.x86_64
	local _abi_release="$(make -s kernelrelease)"
	# 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 modules_install install \
		ARCH="x86_64" \
		INSTALL_MOD_PATH="$_outdir" \
		INSTALL_MOD_STRIP=1 \
		INSTALL_PATH="$_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 _builddir="$srcdir"/build-lts.x86_64
	local _abi_release="$(make -C "$_builddir" -s kernelrelease)"
	# copy the only the parts that we really need for build 3rd party
	# kernel modules and install those as /usr/src/linux-headers,
	# simlar to what ubuntu does
	#
	# this way you dont need to install the 300-400 kernel sources to
	# build a tiny kernel module
	#
	pkgdesc="Headers and script for third party modules for lts kernel"
	depends="$_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 "$dir"
	cp -a "$_builddir"/.config "$_builddir"/localversion-alpine \
		"$dir"/

	make -C "$srcdir"/linux-"$_kernver" \
		O="$dir" \
		ARCH="x86_64" \
		AWK="${AWK:-mawk}" \
		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 arch/x86 -name include -type d -print | while IFS='' read -r folder; do
		find "$folder" -type f
	done | sort -u | cpio -pdm "$dir"

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

	# remove unneeded things
	msg "Removing documentation..."
	rm -rf "$dir"/Documentation
	find "$dir" -type f -name '*.o' -printf 'Removing %P\n' -delete
	
	mkdir -p "$subpkgdir"/lib/modules/"$_abi_release"
	ln -sf /usr/src/linux-headers-"$_abi_release" \
		"$subpkgdir"/lib/modules/"$_abi_release"/build
}

sha512sums="
6ed2a73c2699d0810e54753715635736fc370288ad5ce95c594f2379959b0e418665cd71bc512a0273fe226fe90074d8b10d14c209080a6466498417a4fdda68  linux-6.1.tar.xz
3816cfc8dd14d1c5ced05bbf19b099472c9bbbd1abced32cbb4b6b5baecfaa28c345e4e522648837d98e5bc7c311810cae9160f4c91019bb857a3857076b8e0e  awk.patch
005a39a389103fb4515ee8d8cb74092afaf7a1c2d871189fe7296aba4e272485afa574aa9fde5f9d35e97fda3e5930556ad68d83726b5a26e0c0df9fa35c84d4  config-lts.x86_64
adf488c3d4ef31d011501f91474d9863fc95f402dc2dca5a07a8a9a38101775916d8442962a64e6353152f10e79410bc7a6b2a2eb84e9be993ca2c2334fbb5f9  patch-6.1.54.xz
"