Build Your Own Kernel with Github Action

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This Github Action helps you build kernels. It reads multiple kernel sources from a configuration file and builds them using different toolchains. Additionally, it supports patching the kernel with KernelSU and uploading the built kernel image.

Configure Quick Start Local testing

Github Action

This action contains two jobs: Set-repos and Build-Kernel.

The Set-repos job reads the kernel sources from the configuration file and outputs them to the Build-Kernel job. The Build-Kernel job uses the outputted kernel sources to build the kernels and upload the built kernel images.

Trigger

Event name	Description
workflow_dispatch	Manually run

Workflow

Build Step	Description
Checkout	Check out code
Generate Matrix	Generate kernel source matrix from config file
Create working dir	Create working directory
Install prerequisites	Install necessary dependencies for build
Clone kernel source	Clone kernel source code
Set defconfig	Set default or custom defconfig
Get toolchains	Get toolchains
Set args	Set build arguments
Update KernelSU (optional)	Patch kernel with KernelSU
Make defconfig	Generate kernel configuration file
Build kernel	Build kernel
Upload Image	Upload kernel image
Upload Image.gz	Upload compressed kernel image
Upload dtb	Upload device tree blob file
Upload dtbo.img	Upload device tree overlay file

Configuration File Syntax

Here is an example configuration file:

[
  {
    "kernelSource": {
      "name": "DogDayAndroid",
      "repo": "https://codeberg.org/DogDayAndroid/android_kernel_xiaomi_thyme",
      "branch": "lineage-20.0",
      "device": "thyme",
      "useCustomDefconfig": true,
      "customDefconfig": "thyme_defconfig"
    },
    "withKernelSU": false,
    "toolchains": [
      {
        "repo": "https://android.googlesource.com/platform/prebuilts/gas/linux-x86",
        "branch": "master",
        "name": "gas"
      },
      {
        "repo": "https://gitlab.com/ThankYouMario/android_prebuilts_clang-standalone/",
        "branch": "11",
        "name": "clang"
      }
    ],
    "params": {
      "ARCH": "arm64",
      "CROSS_COMPILE": "aarch64-linux-gnu-",
      "CROSS_COMPILE_ARM32": "arm-linux-gnueabi-",
      "CROSS_COMPILE_COMPAT": "arm-linux-gnueabi-",
      "CLANG_TRIPLE": "aarch64-linux-gnu-",
      "AR": "",
      "CC": "clang"
    }
  },
  {
    "kernelSource": {
      "name": "DogDay-KernelSU",
      "repo": "https://codeberg.org/DogDayAndroid/android_kernel_xiaomi_thyme",
      "branch": "lineage-20.0",
      "device": "thyme"
    },
    "withKernelSU": true,
    "toolchains": [
      {
        "repo": "https://android.googlesource.com/platform/prebuilts/gas/linux-x86",
        "branch": "master",
        "name": "gas"
      },
      {
        "repo": "https://gitlab.com/ThankYouMario/android_prebuilts_clang-standalone/",
        "branch": "11",
        "name": "clang"
      }
    ],
    "params": {
      "ARCH": "arm64",
      "CROSS_COMPILE": "aarch64-linux-gnu-",
      "CROSS_COMPILE_ARM32": "arm-linux-gnueabi-",
      "CROSS_COMPILE_COMPAT": "arm-linux-gnueabi-",
      "CLANG_TRIPLE": "aarch64-linux-gnu-",
      "AR": "",
      "CC": "clang"
    }
  }
]

This JSON code describes a build configuration that includes the following:

Field Name	Description
kernelSource	Information about the kernel source code, including its name, repository URL, branch, and device.
withKernelSU	A boolean value indicating whether the `KernelSU` kernel patch tool was used.
toolchains	An array containing information about the required toolchains, including the repository URL, branch, and name.
params	An object containing information about the build parameters, including architecture type, cross-compiler, and compiler information.

Here's a table of the parameters in the params object:

Parameter Name	Description
ARCH	The architecture type, in this case `arm64`.
CROSS_COMPILE	The cross-compiler prefix, in this case `aarch64-linux-gnu-`.
CROSS_COMPILE_ARM32	The cross-compiler prefix for 32-bit compatibility support, in this case `arm-linux-gnueabi-`.
CROSS_COMPILE_COMPAT	The cross-compiler prefix for 32-bit compatibility support, in this case `arm-linux-gnueabi-`.
CLANG_TRIPLE	The clang compiler's triple, in this case `aarch64-linux-gnu-`.
AR	The archiving program for static libraries, which is empty in this case.
CC	The C compiler, which is `clang` in this case.

These configuration details will be used in the build process to automate the creation of specific kernel image files.

How to use

This project's basic usage is as follows:

Fork this project on GitHub.
Modify the repos.json file through the Github website or pull it to your local machine and commit the changes.
Go to the Action page on Github and find Build kernels, then Run workflow.
Wait for the compilation to finish, then download the compiled product from the corresponding page.
Use your preferred packaging software to package the kernel (AnyKernel3, Android-Image-Kitchen, MagiskBoot, etc.)

Local testing

If you don't want to run the action on Github, you can use nektos/act to test this workflow locally and output the files.

Normal local build (kernel source code is fetched using Git)

This is the recommended local testing process. Simply install nektos/act and run the following command:

# Collect artifacts to /tmp/artifacts folder:
act --artifact-server-path /tmp/artifacts

If you want to store the artifacts in a different location, change /tmp/artifacts to your preferred directory.

If there are errors, use the -v flag to generate an error report and submit an issue. Here's the command:

# Collect artifacts to /tmp/artifacts folder:
act --artifact-server-path /tmp/artifacts -v

Full local build (kernel source code is stored locally)

If you need to perform a completely local build, consider building as follows:

Set up a local Gitea or Gitlab Git service and modify the configuration file address to point to the local service address.
Use git daemon to create a secondary image locally.

This is just a suggestion, and we do not provide a specific guide.