Android Kernel Development - Kernel compilation and Hello World


Introduction


Due to the lack of the material that clearly kick off the  android kernel development , hopefully it will gives the clearer  guide to develop your own android driver and debugging it.

p.s. Due to the version differential, this article  is not ensure all of the Android Version , SDK version,  source  code , and   Emulator is compatible , however,  the door of   research is always opened,   just   feel   free   to contact me  and play together :P

All the materials   are also  saved   in   the VM  ,   you can just directly leverage  the  existing VM Image for  development or  alternatively, as a research and studying, follow the following guide  to create your own workplace. 

 Android kernel didn't have dynamically insmod like the other linux, so this tutorial is trying to build a new Android Kernel and make test our kernel driver as well.

Material

Ubuntu 18.04.2 LTS 
Android studio
Android ndk-r10
Android SDK
Goldfish v3.10
VMWare 15  

Prepare the environment

- Install a  Ubuntu  VM
- Install a Android Studio in your Ubuntu
- Install a latest android SDK
- Install a emulator by Android studio as following:




- Download the R10(suggested version) Android NDK  for compiling your Android Kernel

Compile the goldfish kernel


 - Goldfish is a kernel that opensource by Google, and it is packed with INSMOD and RMMOD for dynamically installing the driver and removing as well.

 - First of all, open your terminal, and execute the following command:

 
 cd ~  
 mkdir kernel  
 cd kernel  
 git clone http://android.googlesource.com/kernel/goldfish.git  
 git branch -a

Afterward, check all the branch it has

p.s. I have test with 3.10 pure version. 

- We could check out by the following command:

 git checkout remotes/origin/android-goldfish-3.10

- We set the compile path and emulator path into the environment variable
- The NDK is used for compile the Goldfish
- The emulator is used for testing



After the variable set, we could enter the command 

 make goldfish_armv7_defconfig  
 make menuconfig



So that you're able to custom your kernel configuration right now
In this tutorial we want to create a kernel with Loadable kernel module capability

so we enable the option that 'Enable loadable module support'


press 'esc' twice for quiting and saving the config 
Enter the following command in current directory  

 gedit Makefile


After that, just simple enter 'make' command for building the kernel, mostly it usually compile perfectly. As the following output, mean the kernel compile success


Next, we could use that newer kernel for launching the emulator! such an exciting moment!




Compile our hello driver 


 Just create a directory and change to there.

Create the Makefile in the directory, as following
ARCH and CROSS_COMPILE have to be as same as the kernel config (arm and arm-linux-androidebi-)

Just check it out,  is there a hello.ko comes out , after compilation

Testing

With the emulator, we connect the adb to the device (adb should be installed along with android studio, so we could just simply enter 'adb' command on the terminal.

 First of all , we check the existence of device

Second, we have to push (moving) the system drier file , to the disk of android emulator.


Thirdly, we connect to the shell of emulator, by using gdb shell command
and change directory to our destination (/data/local/tmp/) and install it on the the system


So, In the example, we just print out that, says, hello Tencent


  
Reference:
https://developer.android.com/ndk/







Comments

Post a Comment

Popular posts from this blog

How does Nested-Virtualization works?

Image
What is Nested virtualization? ----------------------------------------------------------------------------------------------------- Nowadays, Software Security is becoming more important criteria in the industry, and in recent years, virtualization as a popular topic for protecting / attacking a software, however, most of the virtualization technology framework (bluepill-liked) is not provide an ability that let a guest virtualize one more layer, we called it "Nested Virtualization", level 2. Basic Virtual Machine Monitor Architecture ------------------------------------------------------------------------------------------------------ Figure[1] Host VMM trap any type of event which wants to monitor, such as, Interrupt, exception, privileged register access, one of this event is VMX instruction, after VMM loaded, VMM can always monitor a any one of the  VMX instructions, which provide a good chance for us. As following chart: Figure[2] VMM Life Cycle ...
Read more

Understanding ACPI and Device Tree

Image
This blog document and help to understand how ACPI works AML (ACPI Machine Language) AML is compiled binary that written in the ACPI Source Language (ASL) and it is interpreted binary that interpreted by AML interpreter during OS runtime. AML is provided by hardware manufacture and embedded in the firmware, it provides the entire device base hierarchy (all thing that equipped on your motherboard, and cannot be removed.) and function to OS that could interface the dedicated hardware, like PCI-ISA bridge or processor, controlling the power, turn on/off, etc. AML operated by different object type, and defined in definition block in firmware table (DSDT / SSDT) AML object type Scope String   Constant Package Control Method Device   ACPI Object  Naming Convention 1. All object names are 32 bits long. 2. The first byte of a name must be one of 'A' - 'Z', '_'. 3. Each of the remaining bytes of a name must be one of 'A' - 'Z', '0' - ...
Read more

Windows Mini Class and Class Driver internal research notes

Image
Background －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ This is a first windows driver research notes in my blogger. And I will try to keep it simple and clear in this article, for who wants to understand the internal behavior of Class And Mini-Class Driver. －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ Audience －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ For who wants to understand Mini-Class and Class Driver internal. And understanding more about Hid Device stack. －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ Introduction －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ First, We are going to take a example of HidUsb and HidClass, the former is a Mini-Class Driver of a HidClass. We can simply think the relationships between them, is a child and parent relationship, Hidusb is one of the child of HidClass. HidClass can be thought as a helper module( like Dll do) in kernel mode, for helping all Driver who wants to join a hid family. －－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ Research －－－－...
Read more