From eb7e0d42dbe44a452dcbf9afea979ac9591c2fd1 Mon Sep 17 00:00:00 2001
From: Matthieu Coudron <mattator@gmail.com>
Date: Thu, 30 Nov 2017 05:09:00 +0900
Subject: [PATCH] doc: Explain how to hack on kernel
Presents the options available (linuxManualConfig versus overriding
extraConfig, ignoreConfigErrors, autoModules, kernelPreferBuiltin.
For advanced hostPlatform customization refer to the commands shared by ericson1234 at
https://github.com/NixOS/nixpkgs/pull/33813 but it is too advanced to
put in the doc.
---
.../doc/manual/configuration/linux-kernel.xml | 51 +++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/nixos/doc/manual/configuration/linux-kernel.xml b/nixos/doc/manual/configuration/linux-kernel.xml
index 6502aaec83e5..f4d697c42dbd 100644
--- a/nixos/doc/manual/configuration/linux-kernel.xml
+++ b/nixos/doc/manual/configuration/linux-kernel.xml
@@ -66,6 +66,57 @@ nixpkgs.config.packageOverrides = pkgs:
sets the kernel’s TCP keepalive time to 120 seconds. To see the available
parameters, run <command>sysctl -a</command>.
</para>
+ <section>
+ <title>Customize your kernel</title>
+
+ <para>
+ The first step before compiling the kernel is to generate an appropriate
+ <literal>.config</literal> configuration. Either you pass your own config via
+ the <literal>configfile</literal> setting of <literal>linuxManualConfig</literal>:
+ <screen><![CDATA[
+ custom-kernel = super.linuxManualConfig {
+ inherit (super) stdenv hostPlatform;
+ inherit (linux_4_9) src;
+ version = "${linux_4_9.version}-custom";
+
+ configfile = /home/me/my_kernel_config;
+ allowImportFromDerivation = true;
+ };
+ ]]></screen>
+
+You can edit the config with this snippet (by default <command>make menuconfig</command> won't work
+ out of the box on nixos):
+ <screen><![CDATA[
+ nix-shell -E 'with import <nixpkgs> {}; kernelToOverride.overrideAttrs (o: {nativeBuildInputs=o.nativeBuildInputs ++ [ pkgconfig ncurses ];})'
+ ]]></screen>
+
+
+ or you can let nixpkgs generate the configuration.
+ Nixpkgs generates it via answering the interactive kernel utility <command>make config</command>.
+ The answers depend on parameters passed to <filename>pkgs/os-specific/linux/kernel/generic.nix</filename>
+ (which you can influence by overriding <literal>extraConfig, autoModules, modDirVersion, preferBuiltin, extraConfig</literal>).
+<screen><![CDATA[
+
+ mptcp93.override ({
+ name="mptcp-local";
+
+ ignoreConfigErrors = true;
+ autoModules = false;
+ kernelPreferBuiltin = true;
+
+ enableParallelBuilding = true;
+
+ extraConfig = ''
+ DEBUG_KERNEL y
+ FRAME_POINTER y
+ KGDB y
+ KGDB_SERIAL_CONSOLE y
+ DEBUG_INFO y
+ '';
+ });
+ ]]></screen>
+ </para>
+ </section>
<section>
<title>Developing kernel modules</title>