[673b0d8] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
---|
[1770019] | 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
|
---|
[673b0d8] | 3 | <!ENTITY % general-entities SYSTEM "../general.ent">
|
---|
| 4 | %general-entities;
|
---|
| 5 | ]>
|
---|
[81fd230] | 6 | <sect1 id="ch-bootable-kernel" role="wrap">
|
---|
[673b0d8] | 7 | <title>Linux-&linux-version;</title>
|
---|
| 8 | <?dbhtml filename="kernel.html"?>
|
---|
| 9 |
|
---|
| 10 | <indexterm zone="ch-bootable-kernel"><primary sortas="a-Linux">Linux</primary></indexterm>
|
---|
[6370fa6] | 11 |
|
---|
[a001133] | 12 | <sect2 role="package"><title/>
|
---|
[68b786c] | 13 | <para>The Linux package contains the Linux kernel.</para>
|
---|
[5888299] | 14 |
|
---|
[a001133] | 15 | <segmentedlist>
|
---|
| 16 | <segtitle>&buildtime;</segtitle>
|
---|
| 17 | <segtitle>&diskspace;</segtitle>
|
---|
[81fd230] | 18 | <seglistitem><seg>4.20 SBU</seg>
|
---|
| 19 | <seg>181 MB</seg></seglistitem>
|
---|
[a001133] | 20 | </segmentedlist>
|
---|
| 21 |
|
---|
[81fd230] | 22 | <segmentedlist>
|
---|
[45992ae] | 23 | <segtitle>&dependencies;</segtitle>
|
---|
[81fd230] | 24 | <seglistitem><seg>Bash, Binutils, Coreutils, Findutils,
|
---|
| 25 | GCC, Glibc, Grep, Gzip, Make, Modutils, Perl, and Sed</seg></seglistitem>
|
---|
| 26 | </segmentedlist>
|
---|
[a001133] | 27 | </sect2>
|
---|
| 28 |
|
---|
| 29 | <sect2 role="installation">
|
---|
[2081905] | 30 | <title>Installation of the kernel</title>
|
---|
| 31 |
|
---|
[68b786c] | 32 | <para>Building the kernel involves a few steps—configuration, compilation,
|
---|
| 33 | and installation. Read the <filename>README</filename> file in the kernel source
|
---|
| 34 | tree for alternative methods to the way this book configures the kernel.</para>
|
---|
[81fd230] | 35 |
|
---|
[1d609dce] | 36 | <para>Prepare for compilation by running the following command:</para>
|
---|
[b9e738a] | 37 |
|
---|
[1d609dce] | 38 | <screen><userinput>make mrproper</userinput></screen>
|
---|
[b9e738a] | 39 |
|
---|
[81fd230] | 40 | <para>This ensures that the kernel tree is absolutely clean. The
|
---|
| 41 | kernel team recommends that this command be issued prior to each
|
---|
| 42 | kernel compilation. Do not rely on the source tree being clean after
|
---|
| 43 | un-tarring.</para>
|
---|
[d72e04a] | 44 |
|
---|
[81fd230] | 45 | <para>If, in <xref linkend="ch-scripts-console" role=","/> it was decided to
|
---|
| 46 | compile the keymap into the kernel, issue the command below:</para>
|
---|
[89d204ea] | 47 |
|
---|
[0c012ac] | 48 | <screen><userinput>loadkeys -m /usr/share/kbd/keymaps/<replaceable>[path to keymap]</replaceable> > \
|
---|
[d72e04a] | 49 | drivers/char/defkeymap.c</userinput></screen>
|
---|
[89d204ea] | 50 |
|
---|
[81fd230] | 51 | <para>For example, if using a Dutch keyboard, use
|
---|
[845846e0] | 52 | <filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename>.</para>
|
---|
[81fd230] | 53 |
|
---|
[53e6474] | 54 | <para>Configure the kernel via a menu-driven interface. BLFS has some
|
---|
[f134e88] | 55 | information regarding particular kernel configuration requirements of
|
---|
[497b047] | 56 | packages outside of LFS at <ulink
|
---|
[6a6a08a] | 57 | url="&blfs-root;view/svn/longindex.html#kernel-config-index"><phrase
|
---|
| 58 | condition="pdf">&blfs-root;view/svn/
|
---|
| 59 | longindex.html#kernel-config-index</phrase></ulink>:</para>
|
---|
[2081905] | 60 |
|
---|
| 61 | <screen><userinput>make menuconfig</userinput></screen>
|
---|
| 62 |
|
---|
[81fd230] | 63 | <para>Alternatively, <command>make oldconfig</command> may be more appropriate in some
|
---|
| 64 | situations. See the <filename>README</filename> file for more
|
---|
| 65 | information.</para>
|
---|
| 66 |
|
---|
[d6c28f96] | 67 | <note><para>When configuring the kernel, be sure to enable the <quote>Support
|
---|
| 68 | for hot-pluggable devices</quote> option under the <quote>General Setup</quote>
|
---|
| 69 | menu. This enables hotplug events that are used by <command>udev</command> to
|
---|
| 70 | populate the <filename class="directory">/dev</filename> directory with device
|
---|
| 71 | nodes. Likewise, enable the <quote>Virtual memory file system support</quote>
|
---|
| 72 | option under the <quote>File systems</quote>/<quote>Pseudo filesystems</quote>
|
---|
| 73 | menu. This enables the virtual filesystem that the <filename
|
---|
| 74 | class="directory">/dev</filename> directory will be mounted on.</para></note>
|
---|
[81fd230] | 75 |
|
---|
| 76 | <para>If desired, skip kernel configuration by copying the kernel
|
---|
| 77 | config file, <filename>.config</filename>, from the host system
|
---|
| 78 | (assuming it is available) to the unpacked <filename
|
---|
| 79 | class="directory">linux-&linux-version;</filename> directory. However,
|
---|
| 80 | we do not recommend this option. It is often better to explore all the
|
---|
| 81 | configuration menus and create the kernel configuration from
|
---|
| 82 | scratch.</para>
|
---|
| 83 |
|
---|
| 84 | <note><para>NPTL requires the kernel to be compiled with GCC 3.x, in
|
---|
| 85 | this case &gcc-version;. Compiling with 2.95.x is known to cause failures in
|
---|
| 86 | the glibc test suite, so it is not recommended to compile the kernel
|
---|
| 87 | with gcc 2.95.x.</para></note>
|
---|
| 88 |
|
---|
[9dfc02f] | 89 | <para>Compile the kernel image and modules:</para>
|
---|
[2081905] | 90 |
|
---|
[9dfc02f] | 91 | <screen><userinput>make</userinput></screen>
|
---|
[2081905] | 92 |
|
---|
[68b786c] | 93 | <para>If using kernel modules, an <filename>/etc/modprobe.conf</filename> file
|
---|
| 94 | may be needed. Information pertaining to modules and kernel configuration is
|
---|
[81fd230] | 95 | located in the kernel documentation in the <filename
|
---|
[37428334] | 96 | class="directory">linux-&linux-version;/Documentation</filename> directory.
|
---|
| 97 | Also, <filename>modprobe.conf(5)</filename> may be of interest.</para>
|
---|
[68b786c] | 98 |
|
---|
| 99 | <para>Be very careful when reading other documentation relating to kernel
|
---|
| 100 | modules because it usually applies to 2.4.x kernels only. As far as we know,
|
---|
| 101 | kernel configuration issues specific to Hotplug and Udev are not documented.
|
---|
| 102 | The problem is that Udev will create a device node only if Hotplug or a
|
---|
| 103 | user-written script inserts the corresponding module into the kernel, and not
|
---|
| 104 | all modules are detectable by Hotplug. Note that statements like the one below
|
---|
| 105 | in the <filename>/etc/modprobe.conf</filename> file do not work with
|
---|
[81fd230] | 106 | Udev:</para>
|
---|
| 107 |
|
---|
| 108 | <para><screen>alias char-major-XXX some-module</screen></para>
|
---|
| 109 |
|
---|
| 110 | <para>Because of the complications with Hotplug, Udev, and modules, we
|
---|
| 111 | strongly recommend starting with a completely non-modular kernel
|
---|
| 112 | configuration, especially if this is the first time using Udev.</para>
|
---|
| 113 |
|
---|
| 114 | <para>Install the modules, if the kernel configuration uses them:</para>
|
---|
[2081905] | 115 |
|
---|
[9dfc02f] | 116 | <screen><userinput>make modules_install</userinput></screen>
|
---|
[2081905] | 117 |
|
---|
[81fd230] | 118 | <para>After kernel compilation is complete, additional steps are
|
---|
| 119 | required to complete the installation. Some files need to be copied to
|
---|
| 120 | the <filename class="directory">/boot</filename> directory.</para>
|
---|
| 121 |
|
---|
| 122 | <para>The path to the kernel image may vary depending on the platform
|
---|
[d6c28f96] | 123 | being used. The following command assumes an x86 architecture:</para>
|
---|
[2081905] | 124 |
|
---|
[9dfc02f] | 125 | <screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-version;</userinput></screen>
|
---|
[2081905] | 126 |
|
---|
[81fd230] | 127 | <para><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 |
|
---|
[9dfc02f] | 132 | <screen><userinput>cp System.map /boot/System.map-&linux-version;</userinput></screen>
|
---|
[2081905] | 133 |
|
---|
[6a6a08a] | 134 | <beginpage/>
|
---|
| 135 |
|
---|
[81fd230] | 136 | <para>The kernel configuration file <filename>.config</filename>
|
---|
| 137 | produced by the <command>make menuconfig</command> step
|
---|
| 138 | above contains all the configuration selections for the kernel
|
---|
| 139 | that was just compiled. It is a good idea to keep this file for future
|
---|
| 140 | reference:</para>
|
---|
| 141 |
|
---|
[9dfc02f] | 142 | <screen><userinput>cp .config /boot/config-&linux-version;</userinput></screen>
|
---|
[2081905] | 143 |
|
---|
[81fd230] | 144 | <para>It is important to note that the files in the kernel source
|
---|
| 145 | directory are not owned by <emphasis>root</emphasis>. Whenever a
|
---|
| 146 | package is unpacked as user <emphasis>root</emphasis> (like we did
|
---|
| 147 | inside chroot), the files have the user and group IDs of whatever
|
---|
| 148 | they were on the packager's computer. This is usually not a problem
|
---|
| 149 | for any other package to be installed because the source tree is
|
---|
| 150 | removed after the installation. However, the Linux source tree is
|
---|
| 151 | often retained for a long time. Because of this, there is a chance
|
---|
| 152 | that whatever user ID the packager used will be assigned to somebody
|
---|
| 153 | on the machine. That person would then have write access to the kernel
|
---|
| 154 | source.</para>
|
---|
| 155 |
|
---|
| 156 | <para>If the kernel source tree is going to be retained, run
|
---|
| 157 | <command>chown -R 0:0</command> on the <filename
|
---|
| 158 | class="directory">linux-&linux-version;</filename> directory to ensure
|
---|
| 159 | all files are owned by user <emphasis>root</emphasis>.</para>
|
---|
| 160 |
|
---|
| 161 | <warning><para>Some kernel documentation recommends creating a symlink from
|
---|
| 162 | <filename class="symlink">/usr/src/linux</filename> pointing to the kernel
|
---|
| 163 | source directory. This is specific to kernels prior to the 2.6 series and
|
---|
| 164 | <emphasis>must not</emphasis> be created on an LFS system as it can cause
|
---|
| 165 | problems for packages you may wish to build once your base LFS system is
|
---|
[497b047] | 166 | complete.</para>
|
---|
| 167 |
|
---|
| 168 | <para>Also, the headers in the system's
|
---|
| 169 | <filename class="directory">include</filename> directory should
|
---|
| 170 | <emphasis>always</emphasis> be the ones against which Glibc was compiled,
|
---|
| 171 | that is, the ones from the Linux-Libc-Headers package, and therefore, should
|
---|
| 172 | <emphasis>never</emphasis> be replaced by the kernel headers.</para></warning>
|
---|
[2081905] | 173 |
|
---|
| 174 | </sect2>
|
---|
[6910868] | 175 |
|
---|
[673b0d8] | 176 |
|
---|
[c6cb3aa] | 177 | <sect2 id="contents-kernel" role="content"><title>Contents of Linux</title>
|
---|
[673b0d8] | 178 |
|
---|
[81fd230] | 179 | <segmentedlist>
|
---|
| 180 | <segtitle>Installed files</segtitle>
|
---|
[497b047] | 181 | <seglistitem><seg>config-&linux-version;, lfskernel-&linux-version;,
|
---|
| 182 | and System.map-&linux-version;</seg></seglistitem>
|
---|
[81fd230] | 183 | </segmentedlist>
|
---|
| 184 |
|
---|
| 185 | <variablelist><bridgehead renderas="sect3">Short Descriptions</bridgehead>
|
---|
| 186 | <?dbfo list-presentation="list"?>
|
---|
[8f97096] | 187 | <?dbhtml list-presentation="table"?>
|
---|
[81fd230] | 188 |
|
---|
[497b047] | 189 | <varlistentry id="config">
|
---|
| 190 | <term><filename>config-&linux-version;</filename></term>
|
---|
| 191 | <listitem>
|
---|
| 192 | <para>Contains all the configuration selections for the kernel</para>
|
---|
| 193 | <indexterm zone="ch-bootable-kernel config"><primary sortas="e-/boot/config">/boot/config-&linux-version;</primary></indexterm>
|
---|
| 194 | </listitem>
|
---|
| 195 | </varlistentry>
|
---|
| 196 |
|
---|
| 197 | <varlistentry id="lfskernel">
|
---|
| 198 | <term><filename>lfskernel-&linux-version;</filename></term>
|
---|
[81fd230] | 199 | <listitem>
|
---|
| 200 | <para>The engine of the Linux system. When turning on the computer,
|
---|
| 201 | the kernel is the first part of the operating system that gets loaded.
|
---|
| 202 | It detects and initializes all components of the computer's hardware,
|
---|
| 203 | then makes these components available as a tree of files to the
|
---|
| 204 | software and turns a single CPU into a multitasking machine capable
|
---|
[497b047] | 205 | of running scores of programs seemingly at the same time</para>
|
---|
| 206 | <indexterm zone="ch-bootable-kernel lfskernel"><primary sortas="b-lfskernel">lfskernel-&linux-version;</primary></indexterm>
|
---|
[81fd230] | 207 | </listitem>
|
---|
| 208 | </varlistentry>
|
---|
| 209 |
|
---|
| 210 | <varlistentry id="System.map">
|
---|
[497b047] | 211 | <term><filename>System.map-&linux-version;</filename></term>
|
---|
[81fd230] | 212 | <listitem>
|
---|
| 213 | <para>A list of addresses and symbols; it maps the entry points and
|
---|
| 214 | addresses of all the functions and data structures in the
|
---|
| 215 | kernel</para>
|
---|
[497b047] | 216 | <indexterm zone="ch-bootable-kernel System.map"><primary sortas="e-/boot/System.map">/boot/System.map-&linux-version;</primary></indexterm>
|
---|
[81fd230] | 217 | </listitem>
|
---|
| 218 | </varlistentry>
|
---|
| 219 | </variablelist>
|
---|
[673b0d8] | 220 |
|
---|
| 221 | </sect2>
|
---|
| 222 |
|
---|
[6370fa6] | 223 | </sect1>
|
---|