Kernel Modules

Sep 26, 2019
Apr 22, 2020

modules

Linux

IMAGE GALLERY (5)

Kernel modules¹ 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 system²

Built-in kernel modules
Lodable kernel modules

To dynamically load or remove a module, it has to be configured as a loadable module in the kernel configuration (the line related to the module will therefore display the letter M)

ko: kernle objects
so: Shared Objects; The advantage of .so (shared object) over .a library is that they are linked during the runtime i.e. after creation of your .o file -o option in gcc. So, if there’s any change in .so file, you don’t need to recompile your main program. But make sure that your main program is linked to the new .so file with ln command.; files are loaded in python pip modules like spidev
KMOD - kernel modules: a loadable kernel module is an object file that contains code to extend the running kernel

Commands

How to list all loadble kernel modules? lsmod
How to get module information? modinfo
How to dynamically add/remove kernel modules? modprobe -c | less
Move the kernel modules to device FS
- cd /build/bbb/tmp/deploy/ipk/beaglebone_yocto
- scp kernel-module-adis16400-4.18.25-yocto-standard_4.18.25+git0+9e348b6f9d_28e7781d57-r0_beaglebone_yocto.ipk root@192.168.120.141:/home/root
Installl the pkg opkg install
Path on device /lib/modules/4.18.25-yocto-standard/kernel/drivers/iio/imu
Automatically loading kernel modules using systemd? /etc/modules-load.d
Manually reoad/unload a kernel module? modprobe --remove kvm
Kernel Modules path on filesystem? ls -la /lib/modules/(uname --kernel-release)

Debug Kernel

It is assumed that we already know how to compile a kernel, use menuconfig and what kernel options are.

Questions

How to create/write a kernel module?
Have you compiled the linux kernel yourself?

Kernel Modules

IMAGE GALLERY (5)

Commands

Debug Kernel

Questions

Footnotes