Creating Linux Kernel Headers

The document shows the steps to create Linux kernel headers of SP7350 platforms.

Table of Contents

Download Source Files

Please refer to the Downloading and Compiling Code for downloading and compiling the source files for the SP7350 platform.

Configure Build Environment (create linux/kernel/.config)

For example, to configure the build environment for booting from an SD card and using BusyBox for the SP7350 Ev board:

Navigate to the project's top folder and execute make config. This will open a configuration menu with customization options:

Open

1. Select the board by pressing 1 for "SP7350 Ev Board."

2. Choose the boot device; for instance, press 5 for booting from the SD card.

3. Opt for the Linux root file-system by pressing 1 for “BusyBox 1.31.1.”

4. Choose image security by pressing 1 for building “No secure” images.

After making your selections, the system will configure the build environment. This may take several seconds to minutes depending on your computer's performance. Please wait for the process to complete.

Build Code (create linux/kernel/Module.symvers)

Once configurations are set, initiate the build process with the following command:

make

If you're not using the English version of Ubuntu, use:

LANG=C make

This command ensures that make uses English language settings. The build process will compile the code based on your configurations, typically taking a few minutes. Please be patient and let the build complete.

Open

Create Linux Kernel-headers

Generate Linux kernel headers by running:

make headers

After completion, list the contents of the project's top folder using the ll command. The Linux kernel headers will be stored in the linux-headers-5.10.201 folder.

Refer to content of folder: linux-headers-5.10.201

Install Linux Kernel-headers

Before using the Linux kernel headers, copy the linux-headers-5.10.201 folder to /usr/src/ on your target board. Refer to report of ll command in Ubuntu where linux-headers has been copied to:

Remove the soft link named source in /usr/src/linux-headers-5.10.201/ as it's unnecessary. Create a soft link named build at /lib/modules/5.10.201/ pointing to /usr/src/linux-headers-5.10.201:

Generate kernel scripts for aarch64 and copy scripts to /usr/src/linux-headers-5.10.201

Build a Kernel Module (an example)

To ensure compatibility, update your GCC version to 12.3:

Create a simple kernel module by setting up two files: hello.c and Makefile.

hello.c:

Makefile:

Navigate to your module directory and build it using the make command. You should see output similar to this:

This process will generate a hello.ko file, which is the compiled kernel module.

You can load the compiled module into the kernel with the insmod command and verify its presence with lsmod:

Build a Kernel Module with DKMS

Dynamic Kernel Module Support (DKMS) allows you to automatically rebuild kernel modules when a new kernel is installed. Refer to below link for an introduction of DKMS in Ubuntu:

dkms - Dynamic Kernel Module Support

Install DKMS

Create a Sample DKMS Module

First, set up a new directory and create the necessary files:

Then, create the following files:

Makefile:

mymodule.c:

dkms.conf:

Exit the superuser mode:

Add, Build and Install DKMS Module

Add the module to DKMS:

Build the module:

Install the module:

Load the module with modprobe and verify with lsmod:

Appendix: List of Target headers in Makefile within build/ under Project Top-directory