BuildAOSP10Kernel
Jan 29, 2022
Technology
为模拟器emulator编译aosp10的内核.
内核源码获取
需要获取模拟器自身的内核代码，方法是通过adb shell进入到shell下运行uname -a。
尽量找和默认内核差不多的版本的内核进行编译，否则有可能编译出的内核无法启动系统。这里选择的是4.14.112+.
$ git clone https://android.googlesource.com/kernel/goldfish.git
$ git checkout -b android-goldfish-4.14-gchips remotes/origin/android-goldfish-4.14-gchips
$ git branch
* android-goldfish-4.14-gchips
master
获取的内核源码架构如下：
# ls
arch build-kernel.sh CREDITS firmware ipc lib modules.builtin README sound verity_dev_keys.x509
block built-in.o crypto fs Kbuild MAINTAINERS modules.order samples System.map virt
build.config.goldfish.arm64 certs Documentation include Kconfig Makefile Module.symvers scripts tools vmlinux
build.config.goldfish.x86_64 COPYING drivers init kernel mm net security usr vmlinux.o
内核编译链获取
内核编译链在编译好的aosp10源码下，编译方法不再详细讲解。
# ls prebuilts/gcc/linux-x86/x86/x86_64-linux-android-4.9/
bin COPYING COPYING3 COPYING3.LIB COPYING.LIB COPYING.RUNTIME lib libexec MODULE_LICENSE_GPL NOTICE OWNERS repo.prop x86_64-linux-android
# ls prebuilts/qemu-kernel/build-kernel.sh
prebuilts/qemu-kernel/build-kernel.sh
编译
android-goldfish-4.14-gchips内核中需要做以下修改以通过编译:
# vim /security/selinux/include/classmap.h
添加:
#include <linux/socket.h>
# vim scripts/selinux/mdp/mdp.c
# scripts/selinux/genheaders/genheaders.c
去掉头文件包含的 #include <sys/socket.h>
编译配置:
export PATH=$PATH:/home/xxxxx/Code/aosp10/prebuilts/gcc/linux-x86/x86/x86_64-linux-android-4.9/bin
export ARCH=x86_64
export CROSS_COMPILE=x86_64-linux-android-
export REAL_CROSS_COMPILE=x86_64-linux-android-
创建内核定义文件：
# cp arch/x86/configs/x86_64_ranchu_defconfig arch/x86/configs/x86_64_emu_defconfig
编译:
# /home/xxxx/Code/aosp10/prebuilts/qemu-kernel/build-kernel.sh --arch=x86_64
最终编译成品:
# cp /tmp/kernel-qemu/x86_64-4.14.112/kernel-qemu ~/
测试内核
emulator启动的时候显式指定所需的内核:
# emulator -show-kernel -kernel ~/kernel-qemu
检测内核的方式同样是通过adb shell进入到命令行界面下查看内核。