Kernel build environment for OnePlus SM8350 Kernel

This repository uses various scripts to create a building environment for the OnePlus SM8350 kernel tree.

Requirements

• A linux distro
• Git
• A Lineage OS ROM flashable zip, needed to build a working vendor_dlkm.img
• A oneplus-sm8350 kernel tree

Getting Started

• Download the kernel source in the root of this repository
  • The default name for the kernel source tree is android_kernel_oneplus_sm8350

  git clone [your-kernel-repo] android_kernel_oneplus_sm8350
  

• Download a lineage os build and place it in the root of this repository
  • This will be used to extract the vendor_dlkm.img which will be used as a base for the vendor_dlkm.img of the kernel being built
• Run build.sh

  ./build.sh
  

  • This will automatically build and package the kernel in an ak3 zip

Output

Final build files will be written in build folder. The environment produces the following

• Image
  • Kernel image
• vendord_dlkm.img
  • vendord_dlkm partition
• modules
  • Folder containing vendor_ramdisk modules
• kernel-oneplus-sm8350.zip
  • AnyKernel3 flashable zip of the kernel

Scripts Overview

Build.sh

Main script. Contains all possibile commands.

Commands list

• toolchain_setup
  • Checks and sets up the toolchain
  • Implemented in toolchain_setup.sh
• kernel
  • Builds the kernel
  • Implemented in build_kernel.sh
• kernel_clean
  • Runs make clean and make mrproper on the kernel source tree
  • Implemented in build_kernel.sh
• vendor
  • Builds vendro_dlkm.img and ramdisk modules
  • Implemented in vendor.sh
• ak3
  • Packages the kernel with anykernel3
  • See ak3.sh for details.
• lemonade
  • Downloads the latest Lineage OS ROM for OnePlus 9
  • See lineage.sh for details.
• lemonadep
  • Downloads the latest Lineage OS ROM for OnePlus 9 Pro
  • See lineage.sh for details.
• clean
  • Cleans all build artifacts
  • Implemented in build.sh

Utils scripts

These scripts are used by the main scripts for various utility functions

• colors.sh
  • Has cecho function for colored output
• extract_vendor_dlkm.sh
  • Extracts the vendor_dlkm.img from the provided Lineage OS zip file
• set_env.sh
  • Exports to PATH the locations of toolchain utilities
• lineage.sh
  • Downloads the latest Lineage OS rom for the specified device

Toolchain

The toolchain is installed in ~/android/toolchain_oneplus_sm8350 and has the following tools

• build-tools
  • Repository: https://android.googlesource.com/kernel/prebuilts/build-tools
  • Branch: main-kernel-build-2024
  • Contains various tools for building android images
  • Mainly used for mkfs.erofs implementation
• clang-r547379
  • Repository: https://gitlab.com/kei-space/clang/r547379.git
  • Version: 20.0.0
  • Main compiler
  • Compiled from this revision
  • This repository is a mirror of the prebuilt from google
    • This is used instead of google's repository because the google one contains various other clang versions not needed that make the download size unnecessarily big
• payload-dumper-go
  • Repository: https://github.com/ssut/payload-dumper-go
  • Version: latest
  • This tool is used to extract the payload.bin file from the Lineage OS zip
• anykernel3-oneplus-sm8350
  • Repository: https://github.com/Gamesmes90/anykernel3-oneplus-sm8350
  • Branch: lemonade
  • AnyKernel3 Zip Template customized for lemonade/lemonadep devices

Notes

To get a kernel up and running on lemonade/lemonadep, all the modules built with the kernel need to be added in vendor_dlkm.img and a specific set of modules have to be put in vendor_ramdisk and then these have to be flashed with the kernel.

This repository uses a custom AnyKernel3 repo to achieve this.

In addition, the AnyKernel3 repo has a small kernelsu module that runs some kernel tweaks at boot, it is configurable.

Modules in vendor_ramdisk/lib/modules

• msm_drm.ko
• apr_dlkm.ko
• q6_pdr_dlkm.ko
• q6_notifier_dlkm.ko
• adsp_loader_dlkm.ko
• snd_event_dlkm.ko

An alternative to this would be to build the kernel with all the modules as built-in.

vendor_dlkm.img

Using a base image is necessary to build a vendor_dlkm.img, as the image contains other files that are not generated by just building the kernel (e.g. /etc/build.prop generated by the lineage build system). This approach is also easier as it allows to drop-in replacement/new modules in the extracted base image and swiftly generate the erofs image.