If we want to learn android linux kernel, do something about it is the best way. Here records the steps to build and run android linux kernel in emulator. It is a good start for customizing the kernel.
Some steps may have alternative choices, but the following steps are proved by my own practice.
0. We need a linux-x86/linux-x86_64 machine.
1. Download aosp sources. We need the prebuilt gcc tool chain. From https://source.android.com/source/downloading.html.
$cd aosp_master
$repo init -u https://android.googlesource.com/platform/manifest
$repo sync -c -j256
$export PATH=$PATH:`pwd`/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/bin
2. Download and build goldfish kernel source. It's the kernel used by android emulator. From http://source.android.com/source/building-kernels.html.
$git clone https://android.googlesource.com/kernel/goldfish.git
$cd goldfish
# We can use git branch -r to find which remote branch we want to checkout.
$git checkout -t origin/android-goldfish-3.4 -b goldfish3.4
$export ARCH=arm
$export SUBARCH=arm
$export CROSS_COMPILE=arm-eabi-
$make goldfish_armv7_defconfig
$make
Now we get the kernel zImage in arch/arm/boot/zImage
3. Download android sdk. From http://developer.android.com/sdk/installing/index.html and http://developer.android.com/sdk/installing/adding-packages.html.
Download android sdk from http://developer.android.com/sdk/installing/index.html.
Run tools/android, install packages (In my experience, the default option to install is enough for this experiment).
Create an android virtual device for arm_v7. You can see a list of available targets by `tools/android list targets` command. In my enviroment, I create a avd by the following command:
$./android create avd --name myavd --target 1 --abi default/armeabi-v7a
You can see what avds you have by:
$./emulator -list-avds
4. Good, now its time to run emulator with the kernel.
$./emulator -avd myavd -kernel "path to the arch/arm/boot/zImage"
We can verify what kernel is used by add some options in emulator.
$./emulator -avd myavd -kernel "path to the arch/arm/boot/zImage" -show-kernel -verbose 2>&1 | tee emulator.log
Now we can have fun, looking around to see what we can do with the android linux kernel!
