BTFHubForAndroid

We need BTFHub for Android too.

Build Android Common Kernel

build common-android12-5.10 kernel with BTF example

sync kernel source code

git clone https://gerrit.googlesource.com/git-repo
mkdir android-kernel && cd android-kernel
../git-repo/repo init --depth=1 -u https://android.googlesource.com/kernel/manifest -b common-android12-5.10
../git-repo/repo sync -j$(nproc --all)

enable CONFIG_DEBUG_INFO_BTF

cd common
make ARCH=arm64 gki_defconfig
make ARCH=arm64 menuconfig
# plz enable CONFIG_DEBUG_INFO_BTF on GUI
make ARCH=arm64 savedefconfig
cp defconfig arch/arm64/configs/gki_defconfig
rm .config
cd ..

perpare toolchains

mkdir gcc-aosp
wget https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/+archive/refs/tags/android-12.1.0_r27.tar.gz
tar -C gcc-aosp/ -zxvf android-12.1.0_r27.tar.gz

setup env and build, note: clang version can be found at build.config.common

export PATH=/home/kali/Downloads/android-kernel/prebuilts-master/clang/host/linux-x86/clang-r416183b/bin:$PATH
make -j$(nproc --all) O=out ARCH=arm64 CLANG_TRIPLE=aarch64-linux-gnu- CROSS_COMPILE=/home/kali/Downloads/gcc-aosp/bin/aarch64-linux-android- CC=clang LD=ld.lld gki_defconfig
make -j$(nproc --all) O=out ARCH=arm64 CLANG_TRIPLE=aarch64-linux-gnu- CROSS_COMPILE=/home/kali/Downloads/gcc-aosp/bin/aarch64-linux-android- CC=clang LD=ld.lld

vmlinux is out here => ./out/vmlinux

build common-android13-5.10 kernel with BTF example

CONFIG_DEBUG_INFO_BTF enabled default, just directly build

git clone https://gerrit.googlesource.com/git-repo
mkdir android-kernel && cd android-kernel
../git-repo/repo init --depth=1 -u https://mirrors.tuna.tsinghua.edu.cn/git/AOSP/kernel/manifest -b common-android13-5.10
../git-repo/repo sync -j$(nproc --all)

CCACHE="/usr/bin/ccache" LTO=thin BUILD_CONFIG=common/build.config.gki.aarch64 build/build.sh

vmlinux is out here => ./out/android13-5.10/dist/vmlinux

Build Pahole

sudo apt install libdwarf-dev
sudo apt install libdw-dev
git clone https://github.com/acmel/dwarves --depth=1
cd dwarves
mkdir build
cd build
cmake -D__LIB=lib -DBUILD_SHARED_LIBS=OFF ..
sudo make install

Pack vmlinux

pahole --btf_encode_detached a12-5.10-arm64.btf ./out/vmlinux
tar cvfJ "./a12-5.10-arm64.btf.tar.xz" a12-5.10-arm64.btf

Links

• KernelSU_Action build-kernel.yml
• KernelSU gki-kernel.yml
• btfhub update.sh
• 为vmlinux生成BTFhub这样的btf文件
• 安卓通用内核编译零碎记录