mirror of
https://git.linuxfromscratch.org/lfs.git
synced 2026-05-20 05:10:27 -04:00
3ed279fe4d
git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/testing/BOOK@4009 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
231 lines
9.8 KiB
XML
231 lines
9.8 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
|
|
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
|
|
<!ENTITY % general-entities SYSTEM "../general.ent">
|
|
%general-entities;
|
|
]>
|
|
<sect1 id="ch-bootable-kernel" xreflabel="Linux" role="wrap">
|
|
<title>Linux-&linux-version;</title>
|
|
<?dbhtml filename="kernel.html"?>
|
|
|
|
<indexterm zone="ch-bootable-kernel"><primary sortas="a-Linux">Linux</primary></indexterm>
|
|
|
|
<sect2 role="package"><title/>
|
|
<para>The Linux package contains the kernel and the header files.</para>
|
|
|
|
<segmentedlist>
|
|
<segtitle>&buildtime;</segtitle>
|
|
<segtitle>&diskspace;</segtitle>
|
|
<seglistitem><seg>All default options: 4.20 SBU</seg>
|
|
<seg>All default options: 181 MB</seg></seglistitem>
|
|
</segmentedlist>
|
|
|
|
<segmentedlist>
|
|
<segtitle>Linux installation depends on</segtitle>
|
|
<seglistitem><seg>Bash, Binutils, Coreutils, Findutils,
|
|
GCC, Glibc, Grep, Gzip, Make, Modutils, Perl, Sed</seg></seglistitem>
|
|
</segmentedlist>
|
|
</sect2>
|
|
|
|
<sect2 role="installation">
|
|
<title>Installation of the kernel</title>
|
|
|
|
<para>Building the kernel involves a few steps -- configuration,
|
|
compilation, and installation. Read the <filename>README</filename>
|
|
file in the kernel source tree for alternative methods to the way this
|
|
book configures the kernel.</para>
|
|
|
|
<para>Prepare for compilation by running the following command:</para>
|
|
|
|
<screen><userinput>make mrproper</userinput></screen>
|
|
|
|
<para>This ensures that the kernel tree is absolutely clean. The
|
|
kernel team recommends that this command be issued prior to each
|
|
kernel compilation. Do not rely on the source tree being clean after
|
|
un-tarring.</para>
|
|
|
|
<para>Also, ensure that the kernel does not attempt to pass
|
|
hotplugging events to userspace until userspace specifies that it is
|
|
ready:</para>
|
|
|
|
<screen><userinput>sed -i 's@/sbin/hotplug@/bin/true@' kernel/kmod.c</userinput></screen>
|
|
|
|
<para>If, in <xref linkend="ch-scripts-console"/>, you decided to
|
|
compile the keymap into the kernel, issue the command below:</para>
|
|
|
|
<screen><userinput>loadkeys -m /usr/share/kbd/keymaps/<replaceable>[path to keymap]</replaceable> > \
|
|
<replaceable>[unpacked sources dir]</replaceable>/linux-&linux-version;/drivers/char/defkeymap.c</userinput></screen>
|
|
|
|
<para>For example, if using a Dutch keyboard, use
|
|
<filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename>.</para>
|
|
|
|
<para>Configure the kernel via a menu-driven interface:</para>
|
|
|
|
<screen><userinput>make menuconfig</userinput></screen>
|
|
|
|
<para><command>make oldconfig</command> may be more appropriate in some
|
|
situations. See the <filename>README</filename> file for more
|
|
information.</para>
|
|
|
|
<note><para>When you configure the kernel, be sure to enable the
|
|
<quote>Support for hot-pluggable devices</quote> option under the
|
|
<quote>General Setup</quote> menu. This enables hotplug events that
|
|
are used by <command>udev</command> to populate the <filename
|
|
class="directory">/dev</filename> directory with device
|
|
nodes.</para></note>
|
|
|
|
<para>If desired, skip kernel configuration by copying the kernel
|
|
config file, <filename>.config</filename>, from the host system
|
|
(assuming it is available) to the unpacked <filename
|
|
class="directory">linux-&linux-version;</filename> directory. However,
|
|
we do not recommend this option. It is often better to explore all the
|
|
configuration menus and creating the kernel configuration from
|
|
scratch.</para>
|
|
|
|
<para>For POSIX shared memory support, ensure that the kernel config
|
|
option <quote>Virtual memory file system support</quote> is enabled.
|
|
It resides within the <quote>File systems</quote> menu and is normally
|
|
enabled by default.</para>
|
|
|
|
<para>LFS bootscripts make the assumption that either both
|
|
<quote>Support for Host-side USB</quote> and <quote>USB device
|
|
filesystem</quote> have been compiled directly into the kernel, or
|
|
that neither is compiled at all. Bootscripts will not work properly
|
|
if it is a module (usbcore.ko).</para>
|
|
|
|
<note><para>NPTL requires the kernel to be compiled with GCC 3.x, in
|
|
this case &gcc-version;. Compiling with 2.95.x is known to cause failures in
|
|
the glibc testsuite, so it is not recommended to compile the kernel
|
|
with gcc 2.95.x.</para></note>
|
|
|
|
<para>Compile the kernel image and modules:</para>
|
|
|
|
<screen><userinput>make</userinput></screen>
|
|
|
|
<para>If using kernel modules, an
|
|
<filename>/etc/modprobe.conf</filename> file may be needed.
|
|
Information pertaining to modules and to kernel configuration is
|
|
located in the kernel documentation in the <filename
|
|
class="directory">linux-&linux-version;/Documentation</filename>
|
|
directory. The <emphasis>modprobe.conf</emphasis> man page may also be
|
|
of interest.</para>
|
|
|
|
<para>Be very careful when reading other documentation, because it
|
|
usually applies to 2.4.x kernels only. As far as we know, kernel
|
|
configuration issues specific to Hotplug and Udev are not documented.
|
|
The problem is that Udev will create a device node only if Hotplug or
|
|
a user-written script inserts the corresponding module into the
|
|
kernel, and not all modules are detectable by Hotplug. Note that
|
|
statements like <screen>alias char-major-XXX some-module</screen> in
|
|
the <filename>/etc/modprobe.conf</filename> file do not work with
|
|
Udev, and other aliases are often unnecessary with Hotplug.</para>
|
|
|
|
<para>Because of the complications with Hotplug, Udev, and modules, we
|
|
strongly recommend starting with a completely non-modular kernel
|
|
configuration, especially if this is the first time using Udev.</para>
|
|
|
|
<para>Install the modules, if your kernel configuration uses them:</para>
|
|
|
|
<screen><userinput>make modules_install</userinput></screen>
|
|
|
|
<para>If there are many modules and very little space, consider
|
|
stripping and compressing the modules. For most users, such
|
|
compression is not worth the time, but if the system is pressed for
|
|
space, see <ulink
|
|
url="http://www.linux-mips.org/archives/linux-mips/2002-04/msg00031.html"/>.</para>
|
|
|
|
<para>After kernel compilation is complete, additional steps are
|
|
required to complete the installation. Some files need to be copied to
|
|
the <filename class="directory">/boot</filename> directory.</para>
|
|
|
|
<para>The path to the kernel image may vary depending on the platform
|
|
being used. Issue the following command to install the kernel:</para>
|
|
|
|
<screen><userinput>cp arch/i386/boot/bzImage /boot/lfskernel-&linux-version;</userinput></screen>
|
|
|
|
<para><filename>System.map</filename> is a symbol file for the kernel.
|
|
It maps the function entry points of every function in the kernel API,
|
|
as well as the addresses of the kernel data structures for the running
|
|
kernel. Issue the following command to install the map file:</para>
|
|
|
|
<screen><userinput>cp System.map /boot/System.map-&linux-version;</userinput></screen>
|
|
|
|
<para><filename>.config</filename> is the kernel's configuration file
|
|
that was produced by the <command>make menuconfig</command> step
|
|
above. It contains all the configuration selections for the kernel
|
|
that was just compiled. It is a good idea to keep this file for future
|
|
reference:</para>
|
|
|
|
<screen><userinput>cp .config /boot/config-&linux-version;</userinput></screen>
|
|
|
|
<para>It is important to note that the files in the kernel source
|
|
directory are not owned by <emphasis>root</emphasis>. Whenever a
|
|
package is unpacked as user <emphasis>root</emphasis> (like we did
|
|
here inside chroot), the files have the user and group IDs of whatever
|
|
they were on the packager's computer. This is usually not a problem
|
|
for any other package to be installed because the source tree is
|
|
removed after the installation. However, the Linux source tree is
|
|
often retained for a long time. Because of this, there is a chance
|
|
that whatever user ID the packager used will be assigned to somebody
|
|
on the machine. That person would then have write access to the kernel
|
|
source.</para>
|
|
|
|
<para>If the kernel source tree is going to retained, run
|
|
<command>chown -R 0:0</command> on the <filename
|
|
class="directory">linux-&linux-version;</filename> directory to ensure
|
|
all files are owned by user <emphasis>root</emphasis>.</para>
|
|
</sect2>
|
|
|
|
|
|
<sect2 id="contents-kernel" role="content"><title>Contents of Linux</title>
|
|
|
|
<segmentedlist>
|
|
<segtitle>Installed files</segtitle>
|
|
<seglistitem><seg>the kernel, the kernel headers,
|
|
and the System.map</seg></seglistitem>
|
|
</segmentedlist>
|
|
|
|
<variablelist><bridgehead renderas="sect3">Short descriptions</bridgehead>
|
|
<?dbfo list-presentation="list"?>
|
|
|
|
<varlistentry id="kernel">
|
|
<term>The <emphasis>kernel</emphasis></term>
|
|
<listitem>
|
|
<para>the engine of the Linux system. When turning on your computer,
|
|
the kernel is the first part of the operating system that gets loaded.
|
|
It detects and initializes all components of the computer's hardware,
|
|
then makes these components available as a tree of files to the
|
|
software, and turns a single CPU into a multitasking machine capable
|
|
of running scores of programs seemingly at the same time.</para>
|
|
<indexterm zone="ch-bootable-kernel kernel"><primary sortas="b-kernel">kernel</primary></indexterm>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="kernel-headers">
|
|
<term>The <emphasis>kernel headers</emphasis></term>
|
|
<listitem>
|
|
<para>defines the interface to the services that the kernel provides.
|
|
The headers in your system's <filename
|
|
class="directory">include</filename> directory should
|
|
<emphasis>always</emphasis> be the ones against which Glibc was
|
|
compiled and therefore, should <emphasis>not</emphasis> be replaced
|
|
when upgrading the kernel.</para>
|
|
<indexterm zone="ch-bootable-kernel kernel-headers"><primary sortas="e-kernel-headers">kernel headers</primary></indexterm>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="System.map">
|
|
<term><filename>System.map</filename></term>
|
|
<listitem>
|
|
<para>is a list of addresses and symbols. It maps the entry points and
|
|
addresses of all the functions and data structures in the
|
|
kernel.</para>
|
|
<indexterm zone="ch-bootable-kernel System.map"><primary sortas="e-/boot/System.map">/boot/System.map</primary></indexterm>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
</sect2>
|
|
|
|
</sect1>
|
|
|