custom-kernel.sh

#!/bin/bash

set -e

trap '
    ret=$?;
    set +e;
    if [[ $ROOTFS ]]; then
        rm -rf $ROOTFS
    fi
    if [[ $ret -ne 0 ]]; then
        echo FAILED TO INSTALL CUSTOM KERNEL >&2
    fi
    exit $ret;
    ' EXIT

# clean up after ourselves no matter how we die.
trap 'exit 1;' SIGINT

KVER=$(make kernelrelease)
ROOTFS=$(mktemp -d --tmpdir custom-kernel.XXXXXXXX)

# workaround for make modules_install installing in /lib, which will be created
# as a dir if the directory didn't exit
mkdir -p $ROOTFS/usr/lib/modules
ln -s usr/lib $ROOTFS/lib

make modules_install INSTALL_MOD_PATH=$ROOTFS

# on target this will mean nothing
rm $ROOTFS/usr/lib/modules/$KVER/build
rm $ROOTFS/usr/lib/modules/$KVER/source

# copy the kernel image over to /usr/lib/custom-kernel - only one kernel will
# be kept there... user is supposed to call kernel-install on target (which
# copies this kernel to /boot) before installing another kernel
mkdir -p $ROOTFS/usr/lib/custom-kernel/
cp arch/x86/boot/bzImage $ROOTFS/usr/lib/custom-kernel/vmlinuz
echo $KVER > $ROOTFS/usr/lib/custom-kernel/VERSION

# target doesn't need the workaround, so now remove it
rm $ROOTFS/lib

D=$PWD
( cd $ROOTFS && tar -cJf $D/linux-${KVER}.tar.xz * )

xz --stdout .config > linux-${KVER}-config.xz