minimal/src/02_build_kernel.sh

112 lines
3.8 KiB
Bash
Executable File

#!/bin/sh
set -e
# Load common properties and functions in the current script.
. ./common.sh
echo "*** BUILD KERNEL BEGIN ***"
# Change to the kernel source directory which ls finds, e.g. 'linux-4.4.6'.
cd `ls -d $WORK_DIR/kernel/linux-*`
# Cleans up the kernel sources, including configuration files.
echo "Preparing kernel work area."
make mrproper -j $NUM_JOBS
# Read the 'USE_PREDEFINED_KERNEL_CONFIG' property from '.config'
USE_PREDEFINED_KERNEL_CONFIG=`read_property USE_PREDEFINED_KERNEL_CONFIG`
if [ "$USE_PREDEFINED_KERNEL_CONFIG" = "true" -a ! -f $SRC_DIR/minimal_config/kernel.config ] ; then
echo "Config file '$SRC_DIR/minimal_config/kernel.config' does not exist."
USE_PREDEFINED_KERNEL_CONFIG=false
fi
if [ "$USE_PREDEFINED_KERNEL_CONFIG" = "true" ] ; then
# Use predefined configuration file for the kernel.
echo "Using config file '$SRC_DIR/minimal_config/kernel.config'."
cp -f $SRC_DIR/minimal_config/kernel.config .config
else
# Create default configuration file for the kernel.
make defconfig -j $NUM_JOBS
echo "Generated default kernel configuration."
# Changes the name of the system to 'minimal'.
sed -i "s/.*CONFIG_DEFAULT_HOSTNAME.*/CONFIG_DEFAULT_HOSTNAME=\"minimal\"/" .config
# Enable overlay support, e.g. merge ro and rw directories (3.18+).
sed -i "s/.*CONFIG_OVERLAY_FS.*/CONFIG_OVERLAY_FS=y/" .config
# Enable overlayfs redirection (4.10+).
echo "CONFIG_OVERLAY_FS_REDIRECT_DIR=y" >> .config
# Turn on inodes index feature by default (4.13+).
echo "CONFIG_OVERLAY_FS_INDEX=y" >> .config
# Step 1 - disable all active kernel compression options (should be only one).
sed -i "s/.*\\(CONFIG_KERNEL_.*\\)=y/\\#\\ \\1 is not set/" .config
# Step 2 - enable the 'xz' compression option.
sed -i "s/.*CONFIG_KERNEL_XZ.*/CONFIG_KERNEL_XZ=y/" .config
# Enable the VESA framebuffer for graphics support.
sed -i "s/.*CONFIG_FB_VESA.*/CONFIG_FB_VESA=y/" .config
# Read the 'USE_BOOT_LOGO' property from '.config'
USE_BOOT_LOGO=`read_property USE_BOOT_LOGO`
if [ "$USE_BOOT_LOGO" = "true" ] ; then
sed -i "s/.*CONFIG_LOGO_LINUX_CLUT224.*/CONFIG_LOGO_LINUX_CLUT224=y/" .config
echo "Boot logo is enabled."
else
sed -i "s/.*CONFIG_LOGO_LINUX_CLUT224.*/\\# CONFIG_LOGO_LINUX_CLUT224 is not set/" .config
echo "Boot logo is disabled."
fi
# Disable debug symbols in kernel => smaller kernel binary.
sed -i "s/^CONFIG_DEBUG_KERNEL.*/\\# CONFIG_DEBUG_KERNEL is not set/" .config
# Enable the EFI stub
sed -i "s/.*CONFIG_EFI_STUB.*/CONFIG_EFI_STUB=y/" .config
# Request that the firmware clear the contents of RAM after reboot (4.14+).
echo "CONFIG_RESET_ATTACK_MITIGATION=y" >> .config
# Disable Apple Properties (Useful for Macs but useless in general)
echo "CONFIG_APPLE_PROPERTIES=n" >> .config
# Check if we are building 64-bit kernel.
if [ "`grep "CONFIG_X86_64=y" .config`" = "CONFIG_X86_64=y" ] ; then
# Enable the mixed EFI mode when building 64-bit kernel.
echo "CONFIG_EFI_MIXED=y" >> .config
fi
fi
# Compile the kernel with optimization for 'parallel jobs' = 'number of processors'.
# Good explanation of the different kernels:
# http://unix.stackexchange.com/questions/5518/what-is-the-difference-between-the-following-kernel-makefile-terms-vmlinux-vmlinux
echo "Building kernel."
make \
CFLAGS="$CFLAGS" \
bzImage -j $NUM_JOBS
# Prepare the kernel install area.
echo "Removing old kernel artifacts. This may take a while."
rm -rf $KERNEL_INSTALLED
mkdir $KERNEL_INSTALLED
# Install the kernel file.
cp arch/x86/boot/bzImage \
$KERNEL_INSTALLED/kernel
# Install kernel headers which are used later when we build and configure the
# GNU C library (glibc).
echo "Generating kernel headers."
make \
INSTALL_HDR_PATH=$KERNEL_INSTALLED \
headers_install -j $NUM_JOBS
cd $SRC_DIR
echo "*** BUILD KERNEL END ***"