Sunday, April 25, 2021

Linux: Kernel makefile system in brief

 There are multiple components in the kernel build system as shown in the table below:

Components in the Linux kernel build system

The Top makefile builds kernel image and modules. It does this by visiting directories recursively based on the kernel .config. The top Makefile textually includes an arch Makefile with the name arch/$(ARCH)/Makefile. The arch Makefile supplies architecture-specific information to the top Makefile. Each directory has a kbuild makefile which builds built-in or modular targets based on commands passed from above and info n the .config. Makefiles in the kernel are also referred to as kbuild files.

Further reading: A detailed discussion on these is available in the kernel documentation.