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Linux Systems Field Manual

Build, Kconfig, And Modules

Imported from _research/manual-study-linux/build-kconfig-modules.md.

Build, Kconfig, And Modules

Status: implemented source-backed volume.

Source Surface

  • Kconfig: top-level feature configuration entry.
  • Makefile: top-level build orchestration.
  • Documentation/process/coding-style.rst: maintainability contract that shapes acceptable kernel code.

Configuration Model

Linux uses Kconfig to describe selectable features, defaults, dependencies, and menus. This means much of the architecture is conditional. A subsystem is not just code; it is code plus configuration constraints.

For research, that matters because one source path may compile into different runtime behavior depending on CONFIG_* symbols. Examples in this dossier include RCU variants, BPF support, tracing support, preemption, cgroups, and Rust support.

Build Model

The top-level Makefile orchestrates architecture selection, generated files, recursive builds, module targets, and install/package targets. Kernel build is not equivalent to cc *.c; it is a graph of generated headers, configuration outputs, architecture rules, and per-directory object lists.

Style As Architecture

Documentation/process/coding-style.rst belongs in this dossier because style rules affect maintainability at kernel scale. Naming, function shape, error paths, comments, and avoiding cleverness are not cosmetic in a project this large. They are part of how reviewers preserve local reasoning.

Rust Translation

A Rust OS/runtime needs:

  • Declarative feature configuration.
  • Build-time dependency validation.
  • Separate generated artifacts from handwritten code.
  • Per-subsystem feature gates.
  • Style rules for unsafe blocks, error handling, ownership wrappers, and public API stability.

AI-Native Translation

For AI-native development, build metadata should be machine-readable. Agents should know which features are enabled, which subsystem owns a file, what tests cover it, and which generated artifacts are not source of truth.

  • file-notes/linux__Kconfig.md
  • file-notes/linux__Makefile.md
  • file-notes/linux__Documentation__process__coding-style.rst.md