User:mrAureliusR/sandbox/Kconfig

menuconfig for Linux version 4.4.2
Written in	C
Operating system	Linux
Type	Build automation tool
License	GNU General Public License
Website	www.kernel.org

make menuconfig is one of five similar tools that can assist a user in configuring the Linux kernel before building, a necessary step needed to compile the source code. make menuconfig, with a menu-driven user interface, allows the user to choose which features and modules to compile. It is normally invoked using the command make menuconfig; menuconfig is a target in the Linux Makefile.

Overview

make menuconfig was not in the first version of Linux. The predecessor tool is a question-and-answer-based utility (make config, make oldconfig).

Variations of the tool for Linux configuration include:

• make xconfig, which requires Qt
• make gconfig, which uses GTK+
• make nconfig, which is similar to make menuconfig.

All these tools use the Kconfig language internally. Kconfig is also used in other projects, such as Das U-Boot, a bootloader for embedded devices, Buildroot, a tool for generating embedded Linux systems, and BusyBox, a single-executable shell utility toolbox for embedded systems.

Advantages over earlier versions

Despite being a simple design, make menuconfig offers considerable advantages to the question-and-answer-based configuration tool make config, the most notable being a basic search system and the ability to load and save files with filenames different from ".config". make menuconfig allows navigation forwards or backwards directly between features, rather than make config's approach of listing every single option one by one, which requires pressing the ↵ Enter key repeatedly to view all options.

If the user is satisfied with a previous .config file, using make oldconfig uses this previous file to answer all questions that it can, only interactively presenting the new features. This is intended for a version upgrade, but may be appropriate at other times.

make menuconfig is a light load on system resources unlike make xconfig (uses Qt as of version 2.6.31.1, formerly Tk) or make gconfig, which utilizes GTK+. Instead of editing the .config by hand, make menuconfig shows the descriptions of each feature (by pressing the "Help" button while on a menu option), and adds some (primitive in version 2.6.31.1) dependency checking.

The help information is distributed throughout the kernel source tree in the various files called Kconfig.

Dependencies

To use make menuconfig, Linux source is a requirement, a make tool, a C compiler, and the ncurses library.

Key strokes

Main Key strokes

Key stroke	Meaning
?	Option description and tips/Help
←→↑↓PgUpPgDn	Navigate through the kernel features and menuconfig commands.
Esc+Esc	Exit menuconfig or cancel the command.
↵ Enter	Activate a command, or expand a branch.
y	Compile and include this feature inside of the kernel.
m	Compile this feature as a module, separate from the kernel.
n	Do not compile the feature.
/	Search configuration parameter.

Symbols

To the left of the features is the setting (y, M, or empty) enclosed in two punctuation marks.

Dependency information

Symbol	Meaning
< >	No dependencies.
[ ]	A dependency requires this to be compiled-in (y), or not compiled (n).
{ }	A dependency requires this to be a module (m) or compiled-in (y).
- -	A dependency requires this to be compiled-in (y).

Note that the supplied dependency information is primitive, it does not tell you the names of the dependant features.

Other symbols

Symbol	Meaning
--->	Use ↵ Enter to expand this branch as a new window.
(Experimental)	Unstable/lesser code, beware.
(New)	An option not in an older version of Linux.
(Deprecated)	An option that will be removed in future versions.

menuconfig in the kernel-build workflow

The user is encouraged to read the Linux README, since there are also many other make targets (beyond modules_install and install). Each will configure the kernel, but with different features activated, or using a different interactive interface; such as tinyconfig or allyesconfig.

simple (but effective) workflow

1. make menuconfig
2. Next build the compressed kernel and its modules, a long process. make.
3. Install using your favorite method such as make modules_install, make install.

See also

• GNU Compiler Collection
• TUI

References

• The make menuconfig tool itself.
• Linux From Scratch
• How to Build a Minimal Linux System Archived 2009-10-23 at the Wayback Machine
• Creating custom kernels with Debian's kernel-package system
• Cross compiling Linux on IBM System z
• How to roll your own Linux
• Building A Kernel The Traditional Way
• The Linux Kernel HOWTO
• Kconfig language

External links

• The Linux Kernel Archives