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 | <!ENTITY % patches-entities SYSTEM "../../patches.ent"> |
---|
6 | %general-entities; |
---|
7 | %patches-entities; |
---|
8 | ]> |
---|
9 | |
---|
10 | <sect1 id="ch-bootable-kernel" role="wrap"> |
---|
11 | <?dbhtml filename="kernel.html"?> |
---|
12 | |
---|
13 | <title>Linux-&linux-x86-version;</title> |
---|
14 | |
---|
15 | <indexterm zone="ch-bootable-kernel"> |
---|
16 | <primary sortas="a-Linux">Linux</primary> |
---|
17 | </indexterm> |
---|
18 | |
---|
19 | <sect2 role="package"><title/> |
---|
20 | <para>The Linux package contains the Linux kernel.</para> |
---|
21 | |
---|
22 | <segmentedlist> |
---|
23 | <segtitle>&dependencies;</segtitle> |
---|
24 | |
---|
25 | <seglistitem> |
---|
26 | <seg>Bash, Binutils, Coreutils, Findutils, GCC, Glibc, Grep, |
---|
27 | Gzip, Make, Modutils, Perl, and Sed</seg> |
---|
28 | </seglistitem> |
---|
29 | </segmentedlist> |
---|
30 | |
---|
31 | </sect2> |
---|
32 | |
---|
33 | <sect2 role="installation"> |
---|
34 | <title>Installation of the kernel</title> |
---|
35 | |
---|
36 | <para os="a">Building the kernel involves a few steps—configuration, |
---|
37 | compilation, and installation. Read the <filename>README</filename> |
---|
38 | file in the kernel source tree for alternative methods to the way this |
---|
39 | book configures the kernel.</para> |
---|
40 | |
---|
41 | <para os="b">Prepare for compilation by running the following command:</para> |
---|
42 | |
---|
43 | <screen os="c"><userinput>make mrproper</userinput></screen> |
---|
44 | |
---|
45 | <para os="d">This ensures that the kernel tree is absolutely clean. The |
---|
46 | kernel team recommends that this command be issued prior to each |
---|
47 | kernel compilation. Do not rely on the source tree being clean after |
---|
48 | un-tarring.</para> |
---|
49 | |
---|
50 | <para os="e">If, in <xref linkend="ch-scripts-console" role=","/> it was |
---|
51 | decided to compile the keymap into the kernel, issue the command |
---|
52 | below:</para> |
---|
53 | |
---|
54 | <screen os="f"><userinput>loadkeys -m /usr/share/kbd/keymaps/<replaceable>[path to keymap]</replaceable> > \ |
---|
55 | drivers/char/defkeymap.c</userinput></screen> |
---|
56 | |
---|
57 | <para os="g">For example, if using a Dutch keyboard, use |
---|
58 | <filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename>.</para> |
---|
59 | |
---|
60 | <para os="h">Configure the kernel via a menu-driven interface. 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 | <note os="l"> |
---|
79 | <para>Linux-2.6 kernel series requires to be compiled with GCC-3.x or |
---|
80 | later, in this case &gcc-version;. It is not recommended to compile the |
---|
81 | kernel with GCC-2.95.x, as this causes failures in the Glibc test suite. |
---|
82 | Normally, this wouldn't be mentioned as LFS doesn't build GCC-2.95.x. |
---|
83 | Unfortunately, the kernel documentation is outdated and still claims |
---|
84 | GCC-2.95.3 is the recommended compiler.</para> |
---|
85 | </note> |
---|
86 | |
---|
87 | <para os="m">Compile the kernel image and modules:</para> |
---|
88 | |
---|
89 | <screen os="n"><userinput>make</userinput></screen> |
---|
90 | |
---|
91 | <para os="o">If using kernel modules, an |
---|
92 | <filename>/etc/modprobe.conf</filename> file may be needed. |
---|
93 | Information pertaining to modules and kernel configuration is |
---|
94 | located in the kernel documentation in the <filename |
---|
95 | class="directory">Documentation</filename> directory of the kernel |
---|
96 | sources tree. Also, <filename>modprobe.conf(5)</filename> may |
---|
97 | be of interest.</para> |
---|
98 | |
---|
99 | <para os="p">Be very careful when reading other documentation relating to |
---|
100 | kernel modules because it usually applies to 2.4.x kernels only. As |
---|
101 | far as we know, kernel configuration issues specific to Hotplug and |
---|
102 | Udev are not documented. The problem is that Udev will create a device |
---|
103 | node only if Hotplug or a user-written script inserts the corresponding |
---|
104 | module into the kernel, and not all modules are detectable by Hotplug. |
---|
105 | Note that statements like the one below in the |
---|
106 | <filename>/etc/modprobe.conf</filename> file do not work with Udev:</para> |
---|
107 | |
---|
108 | <screen os="q"><literal>alias char-major-XXX some-module</literal></screen> |
---|
109 | |
---|
110 | <para os="r">Because of the complications with Hotplug, Udev, and modules, |
---|
111 | we strongly recommend starting with a completely non-modular kernel |
---|
112 | configuration, especially if this is the first time using Udev.</para> |
---|
113 | |
---|
114 | <para os="s">Install the modules, if the kernel configuration uses |
---|
115 | them:</para> |
---|
116 | |
---|
117 | <screen os="t"><userinput>make modules_install</userinput></screen> |
---|
118 | |
---|
119 | <para os="u">After kernel compilation is complete, additional steps are |
---|
120 | required to complete the installation. Some files need to be copied to |
---|
121 | the <filename class="directory">/boot</filename> directory.</para> |
---|
122 | |
---|
123 | <para os="v">Issue the following command to install the kernel:</para> |
---|
124 | |
---|
125 | <screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-x86-version;</userinput></screen> |
---|
126 | |
---|
127 | <para os="w"><filename>System.map</filename> is a symbol file for the kernel. |
---|
128 | It maps the function entry points of every function in the kernel API, |
---|
129 | as well as the addresses of the kernel data structures for the running |
---|
130 | kernel. Issue the following command to install the map file:</para> |
---|
131 | |
---|
132 | <screen><userinput>cp System.map /boot/System.map-&linux-x86-version;</userinput></screen> |
---|
133 | |
---|
134 | <para os="x">The kernel configuration file <filename>.config</filename> |
---|
135 | produced by the <command>make menuconfig</command> step above contains |
---|
136 | all the configuration selections for the kernel that was just compiled. |
---|
137 | It is a good idea to keep this file for future reference:</para> |
---|
138 | |
---|
139 | <screen><userinput>cp .config /boot/config-&linux-x86-version;</userinput></screen> |
---|
140 | |
---|
141 | <para os="y">It is important to note that the files in the kernel source |
---|
142 | directory are not owned by <systemitem class="username">root</systemitem>. |
---|
143 | Whenever a package is unpacked as user <systemitem |
---|
144 | class="username">root</systemitem> (like we did |
---|
145 | inside chroot), the files have the user and group IDs of whatever |
---|
146 | they were on the packager's computer. This is usually not a problem |
---|
147 | for any other package to be installed because the source tree is |
---|
148 | removed after the installation. However, the Linux source tree is |
---|
149 | often retained for a long time. Because of this, there is a chance |
---|
150 | that whatever user ID the packager used will be assigned to somebody |
---|
151 | on the machine. That person would then have write access to the kernel |
---|
152 | source.</para> |
---|
153 | |
---|
154 | <para>If the kernel source tree is going to retained, run |
---|
155 | <command>chown -R 0:0</command> on the <filename |
---|
156 | class="directory">linux-&linux-x86-version;</filename> directory to |
---|
157 | ensure all files are owned by user <systemitem |
---|
158 | class="username">root</systemitem>.</para> |
---|
159 | |
---|
160 | <warning os="z"> |
---|
161 | <para>Some kernel documentation recommends creating a symlink from |
---|
162 | <filename class="symlink">/usr/src/linux</filename> pointing to the |
---|
163 | kernel source directory. This is specific to kernels prior to the |
---|
164 | 2.6 series and <emphasis>must not</emphasis> be created on an LFS |
---|
165 | system as it can cause problems for packages you may wish to build |
---|
166 | once your base LFS system is complete.</para> |
---|
167 | |
---|
168 | <para>Also, the headers in the system's <filename |
---|
169 | class="directory">include</filename> directory should |
---|
170 | <emphasis>always</emphasis> be the ones against which Glibc was |
---|
171 | compiled, that is, the ones from the Linux-Libc-Headers package, |
---|
172 | and therefore, should <emphasis>never</emphasis> be replaced by |
---|
173 | the kernel headers.</para> |
---|
174 | </warning> |
---|
175 | |
---|
176 | </sect2> |
---|
177 | |
---|
178 | <sect2 id="contents-kernel" role="content"> |
---|
179 | <title>Contents of Linux</title> |
---|
180 | |
---|
181 | <segmentedlist> |
---|
182 | <segtitle>Installed files</segtitle> |
---|
183 | |
---|
184 | <seglistitem> |
---|
185 | <seg>config-[linux-version], lfskernel-[linux-version], |
---|
186 | and System.map-[linux-version]</seg> |
---|
187 | </seglistitem> |
---|
188 | </segmentedlist> |
---|
189 | |
---|
190 | <variablelist> |
---|
191 | <bridgehead renderas="sect3">Short Descriptions</bridgehead> |
---|
192 | <?dbfo list-presentation="list"?> |
---|
193 | <?dbhtml list-presentation="table"?> |
---|
194 | |
---|
195 | <varlistentry id="config"> |
---|
196 | <term><filename>config-[linux-version]</filename></term> |
---|
197 | <listitem> |
---|
198 | <para>Contains all the configuration selections for the kernel</para> |
---|
199 | <indexterm zone="ch-bootable-kernel config"> |
---|
200 | <primary sortas="e-/boot/config">/boot/config-[linux-version]</primary> |
---|
201 | </indexterm> |
---|
202 | </listitem> |
---|
203 | </varlistentry> |
---|
204 | |
---|
205 | <varlistentry id="lfskernel"> |
---|
206 | <term><filename>lfskernel-[linux-version]</filename></term> |
---|
207 | <listitem> |
---|
208 | <para>The engine of the Linux system. When turning on the |
---|
209 | computer, the kernel is the first part of the operating system |
---|
210 | that gets loaded. It detects and initializes all components of |
---|
211 | the computer's hardware, then makes these components available |
---|
212 | as a tree of files to the software and turns a single CPU into |
---|
213 | a multitasking machine capable of running scores of programs |
---|
214 | seemingly at the same time.</para> |
---|
215 | <indexterm zone="ch-bootable-kernel lfskernel"> |
---|
216 | <primary sortas="b-lfskernel">lfskernel-[linux-version]</primary> |
---|
217 | </indexterm> |
---|
218 | </listitem> |
---|
219 | </varlistentry> |
---|
220 | |
---|
221 | <varlistentry id="System.map"> |
---|
222 | <term><filename>System.map-[linux-version]</filename></term> |
---|
223 | <listitem> |
---|
224 | <para>A list of addresses and symbols; it maps the entry points |
---|
225 | and addresses of all the functions and data structures in the |
---|
226 | kernel</para> |
---|
227 | <indexterm zone="ch-bootable-kernel System.map"> |
---|
228 | <primary sortas="e-/boot/System.map">/boot/System.map-[linux-version]</primary> |
---|
229 | </indexterm> |
---|
230 | </listitem> |
---|
231 | </varlistentry> |
---|
232 | |
---|
233 | </variablelist> |
---|
234 | |
---|
235 | </sect2> |
---|
236 | |
---|
237 | </sect1> |
---|