How to create Secure Pi image?

Building a Secure Pi image involves integrating three critical components: U-Boot, Kernel Linux, and the Linux OS. Each layer plays a specific role in enabling the functionality and security of the Secure Pi module, working seamlessly together to create a reliable and efficient platform.

Working Environment

WSL Ubuntu Environment

Ubuntu Version: 20.04

Flex Version: latest (2.6.4)

Bison Version: latest (3.5.1)

Make Version: latest (4.2.1)

GCC Version: latest (9.4.0)

Download and handle the SDK file

• Please go to SDK section to download the full SDK file
• Extract the file using tar command

tar -xzvf SDK_file_name

U-Boot

U-Boot is the foundation of the Secure Pi system, responsible for configuring the hardware and defining the purpose of the MPU's pin layouts.

• Pin Configuration: U-Boot assigns functions to the MPU's pins, ensuring the hardware interfaces are configured correctly.
• Preconfigured SDK: The Secure Pi SDK provides a pre-set U-Boot layer optimized for the module layout, minimizing the need for user modifications.
• Recommendation: Altering the U-Boot layer is not advised, as it may introduce unnecessary errors and disrupt the hardware's compatibility with the system.

Steps and Procedure:

• Run the u-boot build script

./build_sdk_uboot_user.sh

Created files:

It created “splsign.bin” and "u-boot_sign.bin”

Kernel Linux

Kernel Linux serves as the intermediary layer between U-Boot and the Linux OS, acting as a translator and executor for hardware instructions.

• Translation Layer: The kernel allows the MPU to interpret and execute Linux OS instructions effectively.
• Hardware Control: It manages the hardware's operational processes, including the behavior of pins assigned in the U-Boot layer.
• Critical Role: The kernel ensures seamless communication between hardware and software, enabling the entire system to function cohesively.

Steps and Procedure:

• Run the Kernal Linux build script

./build_linux_uboot_user.sh

Created files:

It created “dtb_sign.bin” and “zImage_sign.bin”

Linux OS

Linux OS is the highest layer in the Secure Pi architecture, providing an interface for users to develop and execute complex applications.

• Application Platform: The Linux OS offers a robust and user-friendly environment for running various applications and scripts.
• Versatile Development: Users can leverage scripting languages like Python to build custom solutions tailored to their needs.
• Compatibility: Only Linux OS versions running Kernel Linux 4.14 are compatible with the Secure Pi module, ensuring stability and performance.

Steps and Procedure:

• Set the permission for mkubuntu.sh & ch-mount.sh

chmod +x ch-mount.sh mkubuntu.sh

• Set the environment to create an ubuntu image

sudo ./mkubuntu.sh -env

• Set the basic settings using script number 1

sudo ./mkubuntu.sh -s1

• Get into qemu environment (Please remember to set your own login password)

sudo ./mkubuntu.sh -s2

Start to create your own style of ubuntu image (for default, please use script command -c)

./mkubuntu.sh -c

Created files:

It created “ubuntu_minbase.ext4” and “ubuntu_minbase_256_4k.img”

Gather all the files

For simply the installation progress, Secure Pi has created a installation software with procedure list to allow user could easily work on.

Thus, we recommend to relocated all those generate files to this directory in SDK for a easy installation.

User mode Directory:../SDKdirectory/images/mh_user

Debug mode Directory:../SDKdirectory/images/mh_debug

User mode Directory:../SDKdirectory/images/mh_userDebug mode Directory:../SDKdirectory/images/mh_debug

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