Environment setup for kernel building

README.txt

Paths:
# /home/prebuilts/aarch64-linux-android-4.9    : your toolchain
# /home/work/ZS570KL                           : your working directory
# /home/work/ZS570KL/kernel/msm-3.18           : your kernel source (with AndroidKernel.mk)
# /home/work/ZS570KL/out/KERNEL_OBJ            : compiled kernel objects
# /home/work/ZS570KL/system/lib/modules        : output modules

* execute 'source envsetup.sh' when login
* mkconfig to setup kernel config file for building
* mkkernel to build kernel image and modules
* modules will be at <working_dir>/system/lib/modules
* kernel will be at <working_dir>/out/kernel/msm-3.18/arch/arm64/boot/Image.gz-dtb

envsetup.sh

# basic environment setup
export LC_CTYPE=C
export PATH=/home/prebuilts/aarch64-linux-android-4.9/bin/:$PATH
export TARGET_OUT=system
export TARGET_OUT_INTERMEDIATES=out
export JOB_NUMBER=`grep "^processor" /proc/cpuinfo | wc -l`

# kernel compile flags
export TARGET_KERNEL_ARCH=arm64
export TARGET_KERNEL_CROSS_COMPILE_PREFIX=aarch64-linux-android-
export TARGET_KERNEL_APPEND_DTB=true
export KERNEL_DEFCONFIG=zs570kl-perf_defconfig

# shortcuts
alias mkconfig='make -f kernel/msm-3.18/AndroidKernel.mk "$TARGET_OUT_INTERMEDIATES"/kernel/msm-3.18/.config'
alias mkkernel='make -f kernel/msm-3.18/AndroidKernel.mk "$TARGET_OUT_INTERMEDIATES"/kernel/msm-3.18/arch/arm64/boot/Image.gz-dtb -j"$JOB_NUMBER"'