source: BOOK/bootable/x86/kernel.xml@ cf4bffa

clfs-1.2 clfs-2.1 clfs-3.0.0-systemd clfs-3.0.0-sysvinit systemd sysvinit
Last change on this file since cf4bffa was fb40919, checked in by Chris Staub <chris@…>, 19 years ago

Changed many 'LFS' references to 'CLFS'

  • Property mode set to 100644
File size: 9.4 KB
RevLine 
[3f8be484]1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
3 "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../../general.ent">
5 %general-entities;
6]>
7
8<sect1 id="ch-bootable-kernel" role="wrap">
9 <?dbhtml filename="kernel.html"?>
10
[43daa01]11 <title>Linux-&linux-version;</title>
[3f8be484]12
13 <indexterm zone="ch-bootable-kernel">
14 <primary sortas="a-Linux">Linux</primary>
15 </indexterm>
16
17 <sect2 role="package"><title/>
18 <para>The Linux package contains the Linux kernel.</para>
19
20 </sect2>
21
22 <sect2 role="installation">
23 <title>Installation of the kernel</title>
24
25 <para os="a">Building the kernel involves a few steps&mdash;configuration,
26 compilation, and installation. Read the <filename>README</filename>
27 file in the kernel source tree for alternative methods to the way this
28 book configures the kernel.</para>
29
30 <para os="b">Prepare for compilation by running the following command:</para>
31
32<screen os="c"><userinput>make mrproper</userinput></screen>
33
34 <para os="d">This ensures that the kernel tree is absolutely clean. The
35 kernel team recommends that this command be issued prior to each
36 kernel compilation. Do not rely on the source tree being clean after
37 un-tarring.</para>
38
39 <para os="e">If, in <xref linkend="ch-scripts-console" role=","/> it was
40 decided to compile the keymap into the kernel, issue the command
41 below:</para>
42
43<screen os="f"><userinput>loadkeys -m /usr/share/kbd/keymaps/<replaceable>[path to keymap]</replaceable> &gt; \
44 drivers/char/defkeymap.c</userinput></screen>
45
46 <para os="g">For example, if using a Dutch keyboard, use
47 <filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename>.</para>
48
[77e81f1]49 <para os="h">Configure the kernel via a menu-driven interface.
50 Please note that the udev bootscript requires "rtc" and "tmpfs" to be
51 enabled and built into the kernel, not as modules. BLFS has
[3f8be484]52 some information regarding particular kernel configuration requirements of
[fb40919]53 packages outside of CLFS at <ulink
[3f8be484]54 url="&blfs-root;view/svn/longindex.html#kernel-config-index"/>:</para>
55
56<screen os="i"><userinput>make menuconfig</userinput></screen>
57
58 <para os="j">Alternatively, <command>make oldconfig</command> may be more
59 appropriate in some situations. See the <filename>README</filename>
60 file for more information.</para>
61
62 <para os="k">If desired, skip kernel configuration by copying the kernel
63 config file, <filename>.config</filename>, from the host system
64 (assuming it is available) to the root directory of the unpacked kernel
65 sources. However, we do not recommend this option. It is often better
66 to explore all the configuration menus and create the kernel configuration
67 from scratch.</para>
68
69 <para os="m">Compile the kernel image and modules:</para>
70
71<screen os="n"><userinput>make</userinput></screen>
72
73 <para os="o">If using kernel modules, an
74 <filename>/etc/modprobe.conf</filename> file may be needed.
75 Information pertaining to modules and kernel configuration is
76 located in the kernel documentation in the <filename
77 class="directory">Documentation</filename> directory of the kernel
78 sources tree. Also, <filename>modprobe.conf(5)</filename> may
79 be of interest.</para>
80
81 <para os="p">Be very careful when reading other documentation relating to
82 kernel modules because it usually applies to 2.4.x kernels only. As
83 far as we know, kernel configuration issues specific to Hotplug and
84 Udev are not documented. The problem is that Udev will create a device
85 node only if Hotplug or a user-written script inserts the corresponding
86 module into the kernel, and not all modules are detectable by Hotplug.
87 Note that statements like the one below in the
88 <filename>/etc/modprobe.conf</filename> file do not work with Udev:</para>
89
90<screen os="q"><literal>alias char-major-XXX some-module</literal></screen>
91
[5d9d2e5]92 <para os="r">Because of the complications with Udev and modules,
[3f8be484]93 we strongly recommend starting with a completely non-modular kernel
94 configuration, especially if this is the first time using Udev.</para>
95
96 <para os="s">Install the modules, if the kernel configuration uses
97 them:</para>
98
99<screen os="t"><userinput>make modules_install</userinput></screen>
100
101 <para os="u">After kernel compilation is complete, additional steps are
102 required to complete the installation. Some files need to be copied to
103 the <filename class="directory">/boot</filename> directory.</para>
104
105 <para os="v">Issue the following command to install the kernel:</para>
106
[43daa01]107<screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-version;</userinput></screen>
[3f8be484]108
109 <para os="w"><filename>System.map</filename> is a symbol file for the kernel.
110 It maps the function entry points of every function in the kernel API,
111 as well as the addresses of the kernel data structures for the running
112 kernel. Issue the following command to install the map file:</para>
113
[43daa01]114<screen os="w1"><userinput>cp System.map /boot/System.map-&linux-version;</userinput></screen>
[3f8be484]115
116 <para os="x">The kernel configuration file <filename>.config</filename>
117 produced by the <command>make menuconfig</command> step above contains
118 all the configuration selections for the kernel that was just compiled.
119 It is a good idea to keep this file for future reference:</para>
120
[43daa01]121<screen os="x1"><userinput>cp .config /boot/config-&linux-version;</userinput></screen>
[3f8be484]122
123 <para os="y">It is important to note that the files in the kernel source
124 directory are not owned by <systemitem class="username">root</systemitem>.
125 Whenever a package is unpacked as user <systemitem
126 class="username">root</systemitem> (like we did
127 inside chroot), the files have the user and group IDs of whatever
128 they were on the packager's computer. This is usually not a problem
129 for any other package to be installed because the source tree is
130 removed after the installation. However, the Linux source tree is
131 often retained for a long time. Because of this, there is a chance
132 that whatever user ID the packager used will be assigned to somebody
133 on the machine. That person would then have write access to the kernel
134 source.</para>
135
[43daa01]136 <para os="y1">If the kernel source tree is going to retained, run
[3f8be484]137 <command>chown -R 0:0</command> on the <filename
[43daa01]138 class="directory">linux-&linux-version;</filename> directory to
[3f8be484]139 ensure all files are owned by user <systemitem
140 class="username">root</systemitem>.</para>
141
142 <warning os="z">
143 <para>Some kernel documentation recommends creating a symlink from
144 <filename class="symlink">/usr/src/linux</filename> pointing to the
145 kernel source directory. This is specific to kernels prior to the
[fb40919]146 2.6 series and <emphasis>must not</emphasis> be created on a CLFS
[3f8be484]147 system as it can cause problems for packages you may wish to build
[fb40919]148 once your base CLFS system is complete.</para>
[3f8be484]149
150 <para>Also, the headers in the system's <filename
151 class="directory">include</filename> directory should
152 <emphasis>always</emphasis> be the ones against which Glibc was
[5d9d2e5]153 compiled (from the Linux-Headers package) and should
154 <emphasis>never</emphasis> be replaced by the kernel headers.</para>
[3f8be484]155 </warning>
156
157 </sect2>
158
159 <sect2 id="contents-kernel" role="content">
160 <title>Contents of Linux</title>
161
162 <segmentedlist>
163 <segtitle>Installed files</segtitle>
164
165 <seglistitem>
166 <seg>config-[linux-version], lfskernel-[linux-version],
167 and System.map-[linux-version]</seg>
168 </seglistitem>
169 </segmentedlist>
170
171 <variablelist>
172 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
173 <?dbfo list-presentation="list"?>
174 <?dbhtml list-presentation="table"?>
175
176 <varlistentry id="config">
177 <term><filename>config-[linux-version]</filename></term>
178 <listitem>
179 <para>Contains all the configuration selections for the kernel</para>
180 <indexterm zone="ch-bootable-kernel config">
181 <primary sortas="e-/boot/config">/boot/config-[linux-version]</primary>
182 </indexterm>
183 </listitem>
184 </varlistentry>
185
186 <varlistentry id="lfskernel">
187 <term><filename>lfskernel-[linux-version]</filename></term>
188 <listitem>
189 <para>The engine of the Linux system. When turning on the
190 computer, the kernel is the first part of the operating system
191 that gets loaded. It detects and initializes all components of
192 the computer's hardware, then makes these components available
193 as a tree of files to the software and turns a single CPU into
194 a multitasking machine capable of running scores of programs
195 seemingly at the same time.</para>
196 <indexterm zone="ch-bootable-kernel lfskernel">
197 <primary sortas="b-lfskernel">lfskernel-[linux-version]</primary>
198 </indexterm>
199 </listitem>
200 </varlistentry>
201
202 <varlistentry id="System.map">
203 <term><filename>System.map-[linux-version]</filename></term>
204 <listitem>
205 <para>A list of addresses and symbols; it maps the entry points
206 and addresses of all the functions and data structures in the
207 kernel</para>
208 <indexterm zone="ch-bootable-kernel System.map">
209 <primary sortas="e-/boot/System.map">/boot/System.map-[linux-version]</primary>
210 </indexterm>
211 </listitem>
212 </varlistentry>
213
214 </variablelist>
215
216 </sect2>
217
218</sect1>
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