kconfig-lsp

A language server for the Kconfig configuration language used in Linux, Zephyr, U-Boot, coreboot, and other projects.

Features

LSP Method	Description
textDocument/hover	Keyword documentation and symbol help text
textDocument/definition	Jump to config / menuconfig definition and configdefault blocks, and to the files of source paths
textDocument/references	Find all references to a symbol
textDocument/rename	Rename a symbol in all indexed files
textDocument/completion	Complete keywords and known symbols
textDocument/documentSymbol	Outline of menus, choices, if blocks and symbols
workspace/symbol	Search config / menuconfig definitions in all indexed files
textDocument/foldingRange	Fold menus, choices, if blocks and help text
textDocument/documentLink	Link the paths of source statements to their files
textDocument/publishDiagnostics	Parse errors and undefined symbol warnings

Full coverage of the Kconfig grammar defined in Documentation/kbuild/kconfig-language.rst:

• All entry types: config, menuconfig, choice, comment, menu, if, source, mainmenu
• All attributes: bool, tristate, string, hex, int, prompt, default, def_bool, def_tristate, depends on, select, imply, visible if, range, help, modules, transitional, optional
• Full expression syntax with correct precedence: ||, &&, =, !=, <, >, <=, >=, !, ()
• Macro invocations $(...) and macro variable assignments with =, := and +=
• Line continuations \

Installation

From crates.io

cargo install kconfig-lsp

From source

cargo build --release
cp target/release/kconfig-lsp ~/.local/bin/

Editor Configuration

Neovim

vim.lsp.config.kconfig = {
    root_markers = { '.git', 'Kconfig' },
    cmd = { 'kconfig-lsp' },
    filetypes = { 'kconfig' },
}

vim.lsp.enable('kconfig')

Other Editors

Any LSP client that communicates over stdio can launch kconfig-lsp directly:

kconfig-lsp

Supported Kconfig Syntax

Category	Tokens
Entry keywords	config menuconfig choice endchoice comment menu endmenu if endif source mainmenu
Type keywords	bool tristate string hex int
Attribute keywords	prompt default def_bool def_tristate depends on select imply visible range help ---help--- modules transitional optional
Operators	= != < > <= >= ! && || ( )
Literals	"double quoted" 'single quoted'
Macros	$(cc-option,...) $(success,...) name = value name := value name += value
Zephyr extensions (with zephyr_extensions)	configdefault def_int def_hex def_string rsource osource orsource

Configuration

Options are read from initializationOptions when the server starts, so changing them requires restarting the server. Unknown options and values of the wrong type are reported as a warning.

option	type	default value	description
zephyr_extensions	bool	false	accept configdefault, def_int, def_hex, def_string, rsource, osource and orsource from the Zephyr Kconfig extensions, and do not warn about undefined DT_HAS_*_ENABLED and BOARD_* symbols, because Zephyr makes most of them at build time
kconfig_files	list of strings	["Kconfig", "Kconfig.*", "Kconfig_*"]	patterns of the names of the files to read from the workspace. * matches any characters and ? matches one character. The list replaces the default. For example, use ["Config.in*"] for Buildroot, or ["Kconfig", "Config.in", "Config-*.in"] for OpenWrt. The server also reads the files in the workspace that source statements name. The editor must also give these files the Kconfig file type

Neovim passes them through init_options:

vim.lsp.config.kconfig = {
    root_markers = { '.git', 'Kconfig' },
    cmd = { 'kconfig-lsp' },
    filetypes = { 'kconfig' },
    init_options = { zephyr_extensions = true },
}

Building & Testing

cargo build
cargo test

The test suite includes:

• Lexer coverage for all keyword and operator tokens
• Parser correctness against a comprehensive Kconfig sample
• Semantic analysis: symbol definitions, references, type tracking
• Help text indentation parsing
• Real-world validation against the Linux kernel's init/Kconfig

The kernel test needs a Linux source tree and is skipped by default:

KCONFIG_LINUX_DIR=/path/to/linux cargo test -- --ignored

License

MIT