source: bootable/x86/kernel.xml @ fc626f1

Last change on this file since fc626f1 was 2f33c50, checked in by Jim Gifford <clfs@…>, 18 years ago

r3217@server (orig r1499): chris | 2006-05-01 10:22:43 -0700
Text/grammar fixes

  • Property mode set to 100644
File size: 9.7 KB
Line 
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
11  <title>Linux-&linux-version;</title>
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    <segmentedlist>
21      <segtitle>&dependencies;</segtitle>
22
23      <seglistitem>
24        <seg>Bash, Binutils, Coreutils, Findutils, GCC, Glibc, Grep,
25        Gzip, Kbd, Make, Module-Init-Tools, Perl, and Sed</seg>
26      </seglistitem>
27    </segmentedlist>
28
29  </sect2>
30
31  <sect2 role="installation">
32    <title>Installation of the kernel</title>
33
34    <para os="a">Building the kernel involves a few steps&mdash;configuration,
35    compilation, and installation. Read the <filename>README</filename>
36    file in the kernel source tree for alternative methods to the way this
37    book configures the kernel.</para>
38
39    <para os="b">Prepare for compilation by running the following command:</para>
40
41<screen os="c"><userinput>make mrproper</userinput></screen>
42
43    <para os="d">This ensures that the kernel tree is absolutely clean. The
44    kernel team recommends that this command be issued prior to each
45    kernel compilation. Do not rely on the source tree being clean after
46    un-tarring.</para>
47
48    <para os="e">If, in <xref linkend="ch-scripts-console" role=","/> it was
49    decided to compile the keymap into the kernel, issue the command
50    below:</para>
51
52<screen os="f"><userinput>loadkeys -m /usr/share/kbd/keymaps/<replaceable>[path to  keymap]</replaceable> &gt; \
53    drivers/char/defkeymap.c</userinput></screen>
54
55    <para os="g">For example, if using a Dutch keyboard, use
56    <filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename>.</para>
57
58    <para os="h">Configure the kernel via a menu-driven interface.
59    Please note that the udev bootscript requires "rtc" and "tmpfs" to be
60    enabled and built into the kernel, not as modules. BLFS has
61    some information regarding particular kernel configuration requirements of
62    packages outside of LFS at <ulink
63    url="&blfs-root;view/svn/longindex.html#kernel-config-index"/>:</para>
64
65<screen os="i"><userinput>make menuconfig</userinput></screen>
66
67    <para os="j">Alternatively, <command>make oldconfig</command> may be more
68    appropriate in some situations. See the <filename>README</filename>
69    file for more information.</para>
70
71    <para os="k">If desired, skip kernel configuration by copying the kernel
72    config file, <filename>.config</filename>, from the host system
73    (assuming it is available) to the root directory of the unpacked kernel
74    sources. However, we do not recommend this option. It is often better
75    to explore all the configuration menus and create the kernel configuration
76    from scratch.</para>
77
78    <para os="m">Compile the kernel image and modules:</para>
79
80<screen os="n"><userinput>make</userinput></screen>
81
82    <para os="o">If using kernel modules, an
83    <filename>/etc/modprobe.conf</filename> file may be needed.
84    Information pertaining to modules and kernel configuration is
85    located in the kernel documentation in the <filename
86    class="directory">Documentation</filename> directory of the kernel
87    sources tree. Also, <filename>modprobe.conf(5)</filename> may
88    be of interest.</para>
89
90    <para os="p">Be very careful when reading other documentation relating to
91    kernel modules because it usually applies to 2.4.x kernels only. As
92    far as we know, kernel configuration issues specific to Hotplug and
93    Udev are not documented. The problem is that Udev will create a device
94    node only if Hotplug or a user-written script inserts the corresponding
95    module into the kernel, and not all modules are detectable by Hotplug.
96    Note that statements like the one below in the
97    <filename>/etc/modprobe.conf</filename> file do not work with Udev:</para>
98
99<screen os="q"><literal>alias char-major-XXX some-module</literal></screen>
100
101    <para os="r">Because of the complications with Udev and modules,
102    we strongly recommend starting with a completely non-modular kernel
103    configuration, especially if this is the first time using Udev.</para>
104
105    <para os="s">Install the modules, if the kernel configuration uses
106    them:</para>
107
108<screen os="t"><userinput>make modules_install</userinput></screen>
109
110    <para os="u">After kernel compilation is complete, additional steps are
111    required to complete the installation. Some files need to be copied to
112    the <filename class="directory">/boot</filename> directory.</para>
113
114    <para os="v">Issue the following command to install the kernel:</para>
115
116<screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-version;</userinput></screen>
117
118    <para os="w"><filename>System.map</filename> is a symbol file for the kernel.
119    It maps the function entry points of every function in the kernel API,
120    as well as the addresses of the kernel data structures for the running
121    kernel. Issue the following command to install the map file:</para>
122
123<screen os="w1"><userinput>cp System.map /boot/System.map-&linux-version;</userinput></screen>
124
125    <para os="x">The kernel configuration file <filename>.config</filename>
126    produced by the <command>make menuconfig</command> step above contains
127    all the configuration selections for the kernel that was just compiled.
128    It is a good idea to keep this file for future reference:</para>
129
130<screen os="x1"><userinput>cp .config /boot/config-&linux-version;</userinput></screen>
131
132    <para os="y">It is important to note that the files in the kernel source
133    directory are not owned by <systemitem class="username">root</systemitem>.
134    Whenever a package is unpacked as user <systemitem
135    class="username">root</systemitem> (like we did
136    inside chroot), the files have the user and group IDs of whatever
137    they were on the packager's computer. This is usually not a problem
138    for any other package to be installed because the source tree is
139    removed after the installation. However, the Linux source tree is
140    often retained for a long time.  Because of this, there is a chance
141    that whatever user ID the packager used will be assigned to somebody
142    on the machine. That person would then have write access to the kernel
143    source.</para>
144
145    <para os="y1">If the kernel source tree is going to retained, run
146    <command>chown -R 0:0</command> on the <filename
147    class="directory">linux-&linux-version;</filename> directory to
148    ensure all files are owned by user <systemitem
149    class="username">root</systemitem>.</para>
150
151    <warning os="z">
152      <para>Some kernel documentation recommends creating a symlink from
153      <filename class="symlink">/usr/src/linux</filename> pointing to the
154      kernel source directory. This is specific to kernels prior to the
155      2.6 series and <emphasis>must not</emphasis> be created on an LFS
156      system as it can cause problems for packages you may wish to build
157      once your base LFS system is complete.</para>
158
159      <para>Also, the headers in the system's <filename
160      class="directory">include</filename> directory should
161      <emphasis>always</emphasis> be the ones against which Glibc was
162      compiled (from the Linux-Headers package) and should
163      <emphasis>never</emphasis> be replaced by the kernel headers.</para>
164    </warning>
165
166  </sect2>
167
168  <sect2 id="contents-kernel" role="content">
169    <title>Contents of Linux</title>
170
171    <segmentedlist>
172      <segtitle>Installed files</segtitle>
173
174      <seglistitem>
175        <seg>config-[linux-version], lfskernel-[linux-version],
176        and System.map-[linux-version]</seg>
177      </seglistitem>
178    </segmentedlist>
179
180    <variablelist>
181      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
182      <?dbfo list-presentation="list"?>
183      <?dbhtml list-presentation="table"?>
184
185      <varlistentry id="config">
186        <term><filename>config-[linux-version]</filename></term>
187        <listitem>
188          <para>Contains all the configuration selections for the kernel</para>
189          <indexterm zone="ch-bootable-kernel config">
190            <primary sortas="e-/boot/config">/boot/config-[linux-version]</primary>
191          </indexterm>
192        </listitem>
193      </varlistentry>
194
195      <varlistentry id="lfskernel">
196        <term><filename>lfskernel-[linux-version]</filename></term>
197        <listitem>
198          <para>The engine of the Linux system. When turning on the
199          computer, the kernel is the first part of the operating system
200          that gets loaded. It detects and initializes all components of
201          the computer's hardware, then makes these components available
202          as a tree of files to the software and turns a single CPU into
203          a multitasking machine capable of running scores of programs
204          seemingly at the same time.</para>
205          <indexterm zone="ch-bootable-kernel lfskernel">
206            <primary sortas="b-lfskernel">lfskernel-[linux-version]</primary>
207          </indexterm>
208        </listitem>
209      </varlistentry>
210
211      <varlistentry id="System.map">
212        <term><filename>System.map-[linux-version]</filename></term>
213        <listitem>
214          <para>A list of addresses and symbols; it maps the entry points
215          and addresses of all the functions and data structures in the
216          kernel</para>
217          <indexterm zone="ch-bootable-kernel System.map">
218            <primary sortas="e-/boot/System.map">/boot/System.map-[linux-version]</primary>
219          </indexterm>
220        </listitem>
221      </varlistentry>
222
223    </variablelist>
224
225  </sect2>
226
227</sect1>
Note: See TracBrowser for help on using the repository browser.