source: BOOK/bootable/x86/kernel.xml@ 7ddb05f

sysvinit
Last change on this file since 7ddb05f was 181c0e3, checked in by Chris Staub <chris@…>, 10 years ago

Reworded note on kernel page

Conflicts:

BOOK/boot/x86/kernel.xml
BOOK/bootable/x86/kernel.xml

  • Property mode set to 100644
File size: 9.2 KB
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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/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-version2;</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 </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="p1">Apply the latest Linux sublevel patch:</para>
31
32<screen os="p2"><userinput>xzcat ../&linux-sublevel-patch; | patch -Np1 -i -</userinput></screen>
33
34 <para os="b">Prepare for compilation by running the following command:</para>
35
36<screen os="c"><userinput>make mrproper</userinput></screen>
37
38 <para os="d">This ensures that the kernel tree is absolutely clean. The
39 kernel team recommends that this command be issued prior to each
40 kernel compilation. Do not rely on the source tree being clean after
41 un-tarring.</para>
42
43 <note os="kc"><para>A good starting place for setting up the kernel
44 configuration is to run <command>make defconfig</command>. This will set the base configuration to a good state that takes your current system
45 architecture into account.</para>
46
47 <para>Be sure to configure the following options as
48 shown, or the system might not work correctly or boot at all:</para>
49
50 <screen role="nodump">Device Drivers ---&gt;
51 Generic Driver Options ---&gt;
52 () path to uevent helper (CONFIG_UEVENT_HELPER_PATH)
53 [*] Maintain a devtmpfs filesystem to mount at /dev (CONFIG_DEVTMPFS)
54 [ ] Fallback user-helper invocation for firmware loading (CONFIG_FW_LOADER_USER_HELPER)</screen></note>
55
56 <note os="kd"><para>"EFI Variable support" and
57 "EFI GUID Partition support" are for UEFI systems.</para></note>
58
59 <para os="h">Configure the kernel via a menu-driven interface.
60 CBLFS has some information regarding particular kernel configuration
61 requirements of packages outside of CLFS at <ulink
62 url="&cblfs-root;"/>:</para>
63
64<screen os="i"><userinput>make menuconfig</userinput></screen>
65
66 <para os="j">Alternatively, <command>make oldconfig</command> may be more
67 appropriate in some situations. See the <filename>README</filename>
68 file for more information.</para>
69
70 <para os="k">If desired, skip kernel configuration by copying the kernel
71 config file, <filename>.config</filename>, from the host system
72 (assuming it is available) to the root directory of the unpacked kernel
73 sources. However, we do not recommend this option. It is often better
74 to explore all the configuration menus and create the kernel configuration
75 from scratch.</para>
76
77 <para os="m">Compile the kernel image and modules:</para>
78
79<screen os="n"><userinput>make</userinput></screen>
80
81 <para os="o">If using kernel modules, a configuration file in
82 <filename class="directory">/etc/modprobe.d</filename> file may be needed.
83 Information pertaining to modules and kernel configuration is
84 located in the kernel documentation in the <filename
85 class="directory">Documentation</filename> directory of the kernel
86 sources tree. Also, <filename>modprobe.d(5)</filename> may
87 be of interest.</para>
88
89 <para os="s">Install the modules, if the kernel configuration uses
90 them:</para>
91
92<screen os="t"><userinput>make modules_install</userinput></screen>
93
94 <para os="s2">Install the firmware, if the kernel configuration uses
95 them:</para>
96
97<screen os="t2"><userinput>make firmware_install</userinput></screen>
98
99 <para os="u">After kernel compilation is complete, additional steps are
100 required to complete the installation. Some files need to be copied to
101 the <filename class="directory">/boot</filename> directory.</para>
102
103 <para os="v">Issue the following command to install the kernel:</para>
104
105<screen><userinput>cp -v arch/i386/boot/bzImage /boot/vmlinuz-clfs-&linux-version2;</userinput></screen>
106
107 <para os="w"><filename>System.map</filename> is a symbol file for the kernel.
108 It maps the function entry points of every function in the kernel API,
109 as well as the addresses of the kernel data structures for the running
110 kernel. Issue the following command to install the map file:</para>
111
112<screen os="w1"><userinput>cp -v System.map /boot/System.map-&linux-version2;</userinput></screen>
113
114 <para os="x">The kernel configuration file <filename>.config</filename>
115 produced by the <command>make menuconfig</command> step above contains
116 all the configuration selections for the kernel that was just compiled.
117 It is a good idea to keep this file for future reference:</para>
118
119<screen os="x1"><userinput>cp -v .config /boot/config-&linux-version2;</userinput></screen>
120
121 <para os="y">It is important to note that the files in the kernel source
122 directory are not owned by <systemitem class="username">root</systemitem>.
123 Whenever a package is unpacked as user <systemitem
124 class="username">root</systemitem> (like we do inside the final-system
125 build environment), the files have the user and group IDs of whatever
126 they were on the packager's computer. This is usually not a problem
127 for any other package to be installed because the source tree is
128 removed after the installation. However, the Linux source tree is
129 often retained for a long time. Because of this, there is a chance
130 that whatever user ID the packager used will be assigned to somebody
131 on the machine. That person would then have write access to the kernel
132 source.</para>
133
134 <para os="y1">If the kernel source tree is going to retained, run
135 <command>chown -R 0:0</command> on the <filename
136 class="directory">linux-&linux-version;</filename> directory to
137 ensure all files are owned by user <systemitem
138 class="username">root</systemitem>.</para>
139
140 <warning os="z">
141 <para>Some kernel documentation recommends creating a symlink from
142 <filename class="symlink">/usr/src/linux</filename> pointing to the
143 kernel source directory. This is specific to kernels prior to the
144 2.6 series and <emphasis>must not</emphasis> be created on a CLFS
145 system as it can cause problems for packages you may wish to build
146 once your base CLFS system is complete.</para>
147
148 <para>Also, the headers in the system's <filename
149 class="directory">include</filename> directory should
150 <emphasis>always</emphasis> be the ones against which Glibc was
151 compiled and should <emphasis>never</emphasis> be replaced by headers
152 from a different kernel version.</para>
153 </warning>
154
155 </sect2>
156
157 <sect2 id="contents-kernel" role="content">
158 <title>Contents of Linux</title>
159
160 <segmentedlist>
161 <segtitle>Installed files</segtitle>
162 <segtitle>Installed directory</segtitle>
163
164 <seglistitem>
165 <seg>config-[linux-version], clfskernel-[linux-version],
166 and System.map-[linux-version]</seg>
167 <seg>/lib/modules</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="clfskernel">
187 <term><filename>clfskernel-[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 clfskernel">
197 <primary sortas="b-clfskernel">clfskernel-[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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