#
# Copyright (C) 2006-2009 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
include $(TOPDIR)/rules.mk

override QUILT:=
override HOST_QUILT:=

include $(INCLUDE_DIR)/kernel.mk


PKG_NAME:=linux
PKG_PATCHVER:=5.10
PKG_VERSION:=$(PKG_PATCHVER)$(strip $(LINUX_VERSION-$(PKG_PATCHVER)))
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
PKG_SOURCE_URL:=$(LINUX_SITE)
PKG_HASH:=$(LINUX_KERNEL_HASH-$(strip $(PKG_VERSION)))
PKG_BUILD_DIR:=$(KERNEL_BUILD_DIR)/bpf-headers/$(PKG_NAME)-$(PKG_VERSION)

GENERIC_BACKPORT_DIR := $(GENERIC_PLATFORM_DIR)/backport$(if $(wildcard $(GENERIC_PLATFORM_DIR)/backport-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
GENERIC_PATCH_DIR := $(GENERIC_PLATFORM_DIR)/pending$(if $(wildcard $(GENERIC_PLATFORM_DIR)/pending-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
GENERIC_HACK_DIR := $(GENERIC_PLATFORM_DIR)/hack$(if $(wildcard $(GENERIC_PLATFORM_DIR)/hack-$(PKG_PATCHVER)),-$(PKG_PATCHVER))
GENERIC_FILES_DIR := $(foreach dir,$(wildcard $(GENERIC_PLATFORM_DIR)/files $(GENERIC_PLATFORM_DIR)/files-$(PKG_PATCHVER)),"$(dir)")
PATCH_DIR := $(CURDIR)/patches
FILES_DIR :=

REAL_LINUX_DIR := $(LINUX_DIR)
LINUX_DIR := $(PKG_BUILD_DIR)

include $(INCLUDE_DIR)/bpf.mk
include $(INCLUDE_DIR)/package.mk

define Package/bpf-headers
  SECTION:=kernel
  CATEGORY:=Kernel
  TITLE:=eBPF kernel headers
  BUILDONLY:=1
  HIDDEN:=1
endef

export HOST_EXTRACFLAGS=-I$(STAGING_DIR_HOST)/include

KERNEL_MAKE := \
	$(MAKE) -C $(PKG_BUILD_DIR) \
		ARCH=$(BPF_KARCH) \
		CROSS_COMPILE=$(BPF_ARCH)-linux- \
		LLVM=1 CC="$(CLANG)" LD="$(TARGET_CROSS)ld" \
		HOSTCC="$(HOSTCC)" \
		HOSTCXX="$(HOSTCXX)" \
		HOST_LOADLIBES="-L$(STAGING_DIR_HOST)/lib" \
		KBUILD_HOSTLDLIBS="-L$(STAGING_DIR_HOST)/lib" \
		CONFIG_SHELL="$(BASH)" \
		INSTALL_HDR_PATH="$(PKG_BUILD_DIR)/user_headers"

define Build/Patch
	$(Kernel/Patch/Default)
endef

BPF_DOC = $(PKG_BUILD_DIR)/scripts/bpf_helpers_doc.py

define Build/Configure
	grep -vE 'CONFIG_(CPU_.*ENDIAN|HZ)' $(PKG_BUILD_DIR)/arch/mips/configs/generic_defconfig > $(PKG_BUILD_DIR)/.config
	echo 'CONFIG_CPU_$(if $(CONFIG_BIG_ENDIAN),BIG,LITTLE)_ENDIAN=y' >> $(PKG_BUILD_DIR)/.config
	grep CONFIG_HZ $(REAL_LINUX_DIR)/.config >> $(PKG_BUILD_DIR)/.config
	yes '' | $(KERNEL_MAKE) oldconfig
	grep 'CONFIG_HZ=' $(REAL_LINUX_DIR)/.config | \
		cut -d= -f2 | \
		bc -q $(LINUX_DIR)/kernel/time/timeconst.bc \
		> $(LINUX_DIR)/include/generated/timeconst.h
	$(BPF_DOC) --header \
		--file $(LINUX_DIR)/tools/include/uapi/linux/bpf.h \
		> $(PKG_BUILD_DIR)/tools/lib/bpf/bpf_helper_defs.h
endef

define Build/Compile
	$(KERNEL_MAKE) archprepare headers_install
endef

define Build/InstallDev
	mkdir -p $(1)/bpf-headers/arch $(1)/bpf-headers/tools
	$(CP) \
		$(PKG_BUILD_DIR)/arch/$(BPF_KARCH) \
		$(1)/bpf-headers/arch/
	$(CP) \
		$(PKG_BUILD_DIR)/tools/lib \
		$(PKG_BUILD_DIR)/tools/testing \
		$(1)/bpf-headers/tools/
	$(CP) \
		$(PKG_BUILD_DIR)/include \
		$(PKG_BUILD_DIR)/samples \
		$(PKG_BUILD_DIR)/scripts \
		$(PKG_BUILD_DIR)/user_headers \
		$(1)/bpf-headers
endef

$(eval $(call BuildPackage,bpf-headers))