How does loadable kernel modules work?

How does loadable kernel modules work?

In computing, a loadable kernel module (LKM) is an object file that contains code to extend the running kernel, or so-called base kernel, of an operating system. When the functionality provided by an LKM is no longer required, it can be unloaded in order to free memory and other resources. …

How do Linux kernel modules work?

Linux Kernel Modules. Kernel modules are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This saves time and prevents the possibility of introducing an error in rebuilding and reinstalling the base kernel.

How do I create a Linux kernel module?

The procedure to compile and run a kernel module is as follows:

1. Modify the makefile by replacing every occurrence of helloWorld and kernelRead by the names of the modules you wish to create.
2. compile the modules by running make in the directory where the modules reside.
3. Now become superuser by typing.

How do you write a simple kernel module?

II. Write a Simple Hello World Kernel Module

1. Installing the linux headers. You need to install the linux-headers-..
2. Hello World Module Source Code. Next, create the following hello.
3. Create Makefile to Compile Kernel Module.
4. Insert or Remove the Sample Kernel Module.

What are the modules in Linux?

Linux modules are lumps of code that can be dynamically linked into the kernel at any point after the system has booted. They can be unlinked from the kernel and removed when they are no longer needed. Mostly Linux kernel modules are device drivers, pseudo-device drivers such as network drivers, or file-systems.

How do you call a kernel module?

call a kernel module function from program at user space

1. You can just call any function from other space. You can call syscall function, or interact via procfs or interact with some device file, which is handled by your module.
2. The module have some network management functions.

What is the difference between kernel module and device driver?

Kernel code can be optimized for a specific processor. Kernel modules can be dynamically loaded. The collection of subroutines and data that constitute a device driver can be compiled into a single loadable module of object code. You can add functionality to the kernel while the system is up and running.