feat(coreos-bootkernel) add coreos-bootkernel ebuild

This is a separate kernel package, and configuration, for the "boot"
kernel.  It reuses the same eclass for kernel builds, but does two
things differently for boot kernels:
  - no boot/vmlinuz symlink
  - picks the boot version of the kernel configuration.

sdk_container/src/third_party/coreos-overlay/eclass/cros-kernel2.eclass

@@ -85,6 +85,14 @@ get_build_cfg() {
 	echo "$(cros-workon_get_build_dir)/.config"
 }
 
+get_boot_kernel() {
+	if [[ "${PN}" =~ boot ]] ; then
+		echo "true"
+	else
+		echo "false"
+	fi
+}
+
 get_build_arch() {
 	if [ "${ARCH}" = "arm" ] ; then
 		case "${CHROMEOS_KERNEL_SPLITCONFIG}" in
@@ -232,6 +240,12 @@ cros-kernel2_src_configure() {
 	local config
 	local cfgarch="$(get_build_arch)"
 
+	if [ "$(get_boot_kernel)" = "true" ] ; then
+		boot="_boot"
+	else
+		boot=""
+	fi
+
 	if [ -n "${CHROMEOS_KERNEL_CONFIG}" ]; then
 		config="${S}/${CHROMEOS_KERNEL_CONFIG}"
 	else
@@ -257,7 +271,7 @@ cros-kernel2_src_configure() {
 			chromeos/scripts/prepareconfig ${config} \
 				"$(get_build_cfg)" || die
 		else
-			config="$(defconfig_dir)/${cfgarch}_defconfig"
+			config="$(defconfig_dir)/${cfgarch}_defconfig${boot}"
 			ewarn "Can't prepareconfig, falling back to default " \
 				"${config}"
 			cp "${config}" "$(get_build_cfg)" || die
@@ -442,7 +456,9 @@ cros-kernel2_src_install() {
 		ln -sf $(basename "${zimage_bin}") zImage || die
 	fi
 	if [ ! -e "${D}/boot/vmlinuz" ]; then
-		ln -sf "vmlinuz-${version}" "${D}/boot/vmlinuz" || die
+		if [ "$(get_boot_kernel)" = "false" ]; then
+			ln -sf "vmlinuz-${version}" "${D}/boot/vmlinuz" || die
+		fi
 	fi
 
 	# Check the size of kernel image and issue warning when image size is near

sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-bootkernel/README

@@ -0,0 +1,3 @@
+Go read the README in coreos-kernel for more information on how to setup the
+git tree, this one is identical to that (for the kernel source), but it uses a
+different kernel configuration.

sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-bootkernel/coreos-bootkernel-3.9.5.ebuild

@@ -0,0 +1,26 @@
+# Copyright 1999-2013 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: /var/cvsroot/gentoo-x86/sys-kernel/vanilla-sources/vanilla-sources-3.7.5.ebuild,v 1.1 2013/01/28 13:18:54 ago Exp $
+
+EAPI=4
+CROS_WORKON_COMMIT="da3093ad9f44ba53c3f254b4392f3c742dee41d3"
+CROS_WORKON_TREE="0ff44b050e7f57e7d3743a44af2c9211da30bdb4"
+CROS_WORKON_REPO="git://github.com"
+CROS_WORKON_PROJECT="coreos/linux"
+#inherit cros-workon cros-bootkernel
+inherit cros-workon cros-kernel2
+
+DEPEND="
+	sys-devel/bc
+"
+
+DESCRIPTION="CoreOS kernel"
+HOMEPAGE="http://www.kernel.org"
+SRC_URI="${KERNEL_URI}"
+
+KEYWORDS="amd64 arm x86"
+IUSE="deblob"
+
+src_prepare() {
+	epatch "${FILESDIR}"/no_firmware.patch
+}

sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-bootkernel/files/no_firmware.patch

@@ -0,0 +1,37 @@
+From: Greg Kroah-Hartman <greg@kroah.com>
+Subject: [PATCH] firmware: disable the firmware path entirely
+
+We really don't want to build firmware images into the kernel package at
+all, so rip out all references to the firmware directory that we can
+fine.
+
+
+diff --git a/Makefile b/Makefile
+index 8818c95..0beba841 100644
+--- a/Makefile
++++ b/Makefile
+@@ -519,7 +519,7 @@ scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
+ 
+ # Objects we will link into vmlinux / subdirs we need to visit
+ init-y		:= init/
+-drivers-y	:= drivers/ sound/ firmware/
++drivers-y	:= drivers/ sound/
+ net-y		:= net/
+ libs-y		:= lib/
+ core-y		:= usr/
+@@ -944,7 +944,6 @@ modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
+ 	$(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
+ 	@$(kecho) '  Building modules, stage 2.';
+ 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modbuild
+ 
+ modules.builtin: $(vmlinux-dirs:%=%/modules.builtin)
+ 	$(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
+@@ -980,7 +979,6 @@ _modinst_:
+ # boot script depmod is the master version.
+ PHONY += _modinst_post
+ _modinst_post: _modinst_
+-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.fwinst obj=firmware __fw_modinst
+ 	$(call cmd,depmod)
+ 
+ ifeq ($(CONFIG_MODULE_SIG), y)