How to build kernel for Android
This article explains how to build the Android® kernel binaries (including the kernel image, the modules and the device trees) for a selected STM32 device. It is intended for Distribution Package users.
The AndroidTM Linux® Common kernel is used in the distribution package.
The environment must be installed using the Distribution Package adapted to the selected microprocessor device. See the list of AndroidTM Distribution Package.
To be able to execute the following instructions work from the distribution root directory and initialize the environment:
PC $> source build/envsetup.sh PC $> bspsetup PC $> lunch aosp-<BoardId>-userdebug
The distribution includes prebuilt kernel binaries used to generate the partition images (
vendor). These binaries are available in the
2 Partition layout
The Linux® kernel binary is part of the
The Linux® kernel drivers built as loadable modules (
.ko files) are part of the
The device tree binary file is part of the
For information on the complete partition layout for the selected development platform, refer to the corresponding Flash mapping article named Your_development_platform Flash mapping for Android. Example: STM32MP15 Flash mapping for Android for the STM32MP15 boards.
All Flash mapping for AndroidTM articles belong to the Category:Flash mapping for Android.
3 Load the kernel sources
By default, the kernel sources are not part of the STM32MPU distribution for AndroidTM. To load the sources, execute the following instruction:
PC $> load_kernel
This will load the Android™ common Linux® kernel sources. These are located in the
4 Build the kernel
After retrieving the kernel sources, it is built using:
PC $> build_kernel
The output is located in:
This instruction generates the kernel, DT and gpu modules. It is possible to generate them separately from one another:
PC $> build_kernel dtb PC $> build_kernel gpu PC $> build_kernel vmlinux
For more details check the instruction helper:
PC $> build_kernel --help PC $> Usage: build_kernel [Options] [Command]
This script builds the Linux® kernel source
PC $> -h/--help: print this message PC $> -i/--install: update prebuilt images PC $> -v/--version: get script version PC $> --verbose: enable verbose output.
Instruction: only one instruction is supported at a time.
PC $> dtb: build only device-tree binaries PC $> gpu: build only gpu module (the kernel is build if not already performed) PC $> defaultconfig: build only .config based on default defconfig files and fragments PC $> menuconfig: display standard Linux® kernel menuconfig interface PC $> modules: build only kernel modules binaries (kernel is build if not already performed) PC $> mrproper: execute make mrproper on targeted kernel PC $> vmlinux: build only kernel vmlinux binary
5 Integrate the kernel
To integrate the new kernel, modules or/and device tree in the distribution, the prebuilt images have to be update first:
PC $> build_kernel -i
PC $> build_kernel -i dtb PC $> build_kernel -i modules PC $> build_kernel -i vmlinux
And then build the distribution to generate output images.
PC $> make -j
Finally, update the associated device partitions. Refer to How to populate boards for Android
6 Customize the kernel
If the kernel configuration has to be changed, refer to How to customize kernel for Android page.