#
# Copyright 2021 Google LLC
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# version 2 as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#

# Check for EAPI 5+
case "${EAPI:-0}" in
0|1|2|3|4) die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}" ;;
5|6) inherit eapi7-ver ;;
7) ;;
esac

inherit linux-info linux-mod toolchain-funcs

IUSE="
	+clang
	+llvm_ias
	module_sign
	platform-key
"

REQUIRED_USE="
	llvm_ias? ( clang )
"

DEPEND="
	platform-key? ( sys-boot/platform-key )
	virtual/linux-sources
"

# Because our kernel version string ends with '+' (e.g.
# "4.4.21+"), Gentoo Linux's linux-info.eclass cannot locate the kernel build
# output directory. Hence we set it up here.
KBUILD_OUTPUT="${KERNEL_DIR}"/build

pkg_setup() {
	CONFIG_CHECK=""
	MODULE_NAMES="${MODULE_NAME}(::)"
	linux-mod_pkg_setup
	BUILD_PARAMS="KERNEL_SOURCES=${KV_DIR} KBUILD_OUTPUT=${KBUILD_OUTPUT}"
}

cos-linux-mod_src_prepare() {
	# Allowing gcc to be used when clang is not set.
	# This is copied from cros-kernel2.eclass to make sure the third
	# party kernel module uses the same compiler as kernel.
	use clang || cros_use_gcc

	default
}

cos-linux-mod_src_compile() {
	# Assemble with LLVM's integrated assembler on x86_64 and aarch64
	if use llvm_ias; then
		export LLVM_IAS=1
	fi
	BUILD_TARGETS="module" linux-mod_src_compile
}

cos-linux-mod_src_install() {
	local key_path="${KBUILD_OUTPUT}"/certs
	if use platform-key ; then
		key_path="${ROOT}"/build/share/platform-key
	fi
	if use module_sign ; then
		# Sign the module first.
		cp ${MODULE_NAME}.ko ${MODULE_NAME}.ko.orig
		"${KBUILD_OUTPUT}"/scripts/sign-file \
			sha256 \
			"${key_path}"/signing_key.pem \
			"${key_path}"/signing_key.x509 \
			${MODULE_NAME}.ko
	fi

	linux-mod_src_install
}