Android kernel buildscript

build_kernel.sh

#!/bin/bash

#
# Copyright (C) 2022 A2L5E0X1
#
# Simple script for building Android kernels with multiple arch support and custom toolchain option
#

#
# Changelog:
#
# rev 1: initial upload, everything working fine!
#

# Config - only touch if you know what you are doing
KERNEL_OBJ=out
TARGET_OUT_DIR=$2_out
THREADS=$(nproc --all)
GIT=$(which git)
TOOLCHAIN_BRANCH=android-9.0.0_r61
LOCAL_PATH=`pwd`

# Bypasses
SKIP_TOOLCHAIN_RECLONE=true
SKIP_KERNEL_OBJ_CLEAN=false

# Simplify the parameters - DO NOT TOUCH
ARCH=$1
KERNEL_CONFIG=$2
CUSTOM_TOOLCHAIN=$3
CUSTOM_CC=$4

# Intro
echo "~~~ Simple Kernel Buildscript ~~~"
echo "~~~        by A2L5E0X1        ~~~"
sleep 1

# Check for parameters
if [ -z $ARCH ] || [ -z $KERNEL_CONFIG ]; then
    echo "Usage: $(basename $0) <arch> <defconfig> [toolchain path] [custom_cc]"
    echo "Example: $(basename $0) arm64 sample_defconfig /home/nobody/kernel/toolchain/aarch64-linux-android-4.9 aarch64-linux-android-"
    exit 1
fi

# Some CUSTOM_TOOLCHAIN checks
if [ ! -z $CUSTOM_TOOLCHAIN ]; then
    # Check if CUSTOM_CC is defined when CUSTOM_TOOLCHAIN is defined
    if [ -z $CUSTOM_CC ]; then
	echo "ERROR: CUSTOM_TOOLCHAIN defined but CUSTOM_CC isn't!"
	exit 1
    fi
    # Check if CUSTOM_TOOLCHAIN is actually present
    if [ ! -f $CUSTOM_TOOLCHAIN/bin/${CUSTOM_CC}gcc ]; then
	echo "ERROR: CUSTOM_TOOLCHAIN or CUSTOM_CC is invalid! Clone the toolchain or fix the path!"
	exit 1
    fi
fi

# Check if the script is located in an actual kernel source
if [ ! -f Makefile ]; then
    echo "ERROR: This doesn't look like a kernel source! Please put this script into a kernel source!"
    exit 1
fi

# Check if the defconfig exists and if the arch is correct
if [ ! -f arch/$ARCH/configs/$KERNEL_CONFIG ]; then
    echo "ERROR: Either the defconfig doesn't exist or the arch is wrong. Please correct it!"
    exit 1
fi

# Check for git
if [ ! -f $(which git) ]; then
    echo "ERROR: git is not installed. Please install it or set PATH!"
    exit 1
fi

# Choose and clone toolchain
if [ -z $CUSTOM_TOOLCHAIN ]; then
    # Delete existing toolchain
    if [ -d kernel_toolchain ] && [ "$SKIP_TOOLCHAIN_RECLONE" != "true" ]; then
	rm -rf kernel_toolchain
    fi
    # Choose toolchain
    if [ $ARCH = "arm" ]; then
	export CROSS_COMPILE="arm-linux-android-"
	export TOOLCHAIN="arm/arm-linux-android-4.9"
	export TOOLCHAIN_PATH="kernel_toolchain/arm-linux-androideabi-4.9"
    elif [ $ARCH = "arm64" ]; then
	export CROSS_COMPILE="aarch64-linux-android-"
	export TOOLCHAIN="aarch64/aarch64-linux-android-4.9"
	export TOOLCHAIN_PATH="kernel_toolchain/aarch64-linux-androideabi-4.9"
    elif [ $ARCH = "x86" ]; then
    	export CROSS_COMPILE="x86_64-linux-android-"
    	export TOOLCHAIN="x86_64/x86_64-linux-android-4.9"
    	export TOOLCHAIN_PATH="kernel_toolchain/x86_64-linux-androideabi-4.9"
    else
	echo "Couldn't find toolchain for your arch. I would recommend you to use a custom toolchain!"
	exit 1
    fi
    # Check for darwin
    if [ "$OSTYPE" = "darwin*" ]; then
	export TOOLCHAIN_OSTYPE="darwin-x86"
    else
	export TOOLCHAIN_OSTYPE="linux-x86"
    fi
    # Clone toolchain
    "$GIT" clone https://android.googlesource.com/platform/prebuilts/gcc/"$TOOLCHAIN_OSTYPE"/"$TOOLCHAIN" -b "$TOOLCHAIN_BRANCH" "$TOOLCHAIN_PATH" --depth=1
else
    # Export custom toolchain cc
    export CROSS_COMPILE=$CUSTOM_CC
    export TOOLCHAIN_PATH=$CUSTOM_TOOLCHAIN
fi

# Create OUT_DIR
if [ ! -d $KERNEL_OBJ ]; then
    mkdir $KERNEL_OBJ
elif [ $SKIP_KERNEL_OBJ_CLEAN != true ]; then
    rm -rf $KERNEL_OBJ; mkdir $KERNEL_OBJ
fi

# Export toolchain to PATH
export PATH="$LOCAL_PATH/$TOOLCHAIN_PATH/bin:$PATH"

# Start kernel build
echo "~                                 "
echo "~ INFO: building $KERNEL_CONFIG..."
echo "~                                 "
make ARCH=$ARCH O=$KERNEL_OBJ -j$THREADS $KERNEL_CONFIG

if [ ! -f $KERNEL_OBJ/.config ]; then
    echo "ERROR: Building $KERNEL_CONFIG failed! Check the log above!"
    exit 1
fi

echo "~                         "
echo "~ INFO: building kernel..."
echo "~                         "
make ARCH=$ARCH O=$KERNEL_OBJ -j$THREADS

# Check if kernel built successfully. If yes, copy to TARGET_OUT_DIR.
if [ ! -f $KERNEL_OBJ/arch/$ARCH/boot/Image ]; then
    echo "ERROR: Kernel build failed! Check the log above!"
    echo "Buildissues related to yylloc? Try this commit: https://github.com/hi6250-8/android_kernel_huawei_hi6250/commit/cb65db6f628c08f34f0ca95f49d054779b58cc1d"
    exit 1
else
    if [ -d $TARGET_OUT_DIR ]; then
	rm -rf $TARGET_OUT_DIR
    fi
    cp -r $KERNEL_OBJ/arch/$ARCH/boot $TARGET_OUT_DIR
    if [ $(find $KERNEL_OBJ -name "*.ko") != "" ]; then
	mkdir $TARGET_OUT_DIR/modules
	for module in $(find $KERNEL_OBJ -name "*.ko"); do cp $module $TARGET_OUT_DIR/modules/; done
    fi
fi

echo "~                                                                     "
echo "~ INFO: Successfully built kernel! You can find it in $TARGET_OUT_DIR."
echo "~                                                                     "
echo "* Kernel binaries"
ls $TARGET_OUT_DIR
if [ -d $TARGET_OUT_DIR/arch/$ARCH/boot/dts ]; then
echo "* Kernel DTBs"
find $TARGET_OUT_DIR -name '*.dtb*'
fi
if [ -d $TARGET_OUT_DIR/modules ]; then
echo "* Kernel Modules"
ls $TARGET_OUT_DIR/modules
fi