mirror of
https://git.linuxfromscratch.org/lfs.git
synced 2025-01-19 05:27:39 +00:00
0c012ac2c9
git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@3819 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
218 lines
9.8 KiB
XML
218 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. If you don't like the way this book configures the kernel, view
|
|
the <filename>README</filename> file in the kernel source tree for alternative
|
|
methods.</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 <emphasis>each</emphasis>
|
|
kernel compilation. You shouldn't 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 you want
|
|
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 you have a Dutch keyboard, you would 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>
|
|
|
|
<para>If you wish, you may skip kernel configuration by simply copying the
|
|
kernel config file, <filename>.config</filename>, from your host system
|
|
(assuming it is available) to the unpacked <filename class="directory">linux-&linux-version;</filename>
|
|
directory. However, we
|
|
don't recommend this option. You're much better off exploring all the
|
|
configuration menus and creating your own 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 you either compile
|
|
both <quote>Support for Host-side USB</quote> and
|
|
<quote>USB device filesystem</quote> directly into the kernel, or don't compile them at
|
|
all. Bootscripts will not work properly if it is a module (<filename>usbcore.ko</filename>).</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 do <emphasis>not</emphasis> compile the kernel with gcc 2.95.x
|
|
unless you know what you're getting yourself into.</para></note>
|
|
|
|
<para>Compile the kernel image and modules:</para>
|
|
|
|
<screen><userinput>make</userinput></screen>
|
|
|
|
<para>If you intend to use kernel modules, you may need an
|
|
<filename>/etc/modprobe.conf</filename> file. Information pertaining
|
|
to modules and to kernel configuration in general may be found in the
|
|
kernel documentation, which is found in the
|
|
<filename class="directory">linux-&linux-version;/Documentation</filename> directory.
|
|
The modprobe.conf man page
|
|
<!-- removed for review from tldp.org
|
|
and the kernel HOWTO at
|
|
<ulink url="http://www.tldp.org/HOWTO/Kernel-HOWTO.html"/> -->
|
|
may also be of interest to you.</para>
|
|
|
|
<para>Be very suspicious while reading other documentation, because it
|
|
usually applies to 2.4.x kernels only. As far as the editors know, kernel
|
|
configuration issues specific to Hotplug and Udev
|
|
are documented nowhere. 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 <filename>/etc/modprobe.conf</filename> file don't work with
|
|
Udev, and other aliases are often unnecessary with Hotplug.</para>
|
|
|
|
<para>Because of all those compilcations with Hotplug, Udev and modules, we
|
|
strongly recommend you to start with a completely non-modular kernel
|
|
configuration, especially if this is the first time you use Udev.</para>
|
|
|
|
<para>Install the modules, if your kernel configuration uses them:</para>
|
|
|
|
<screen><userinput>make modules_install</userinput></screen>
|
|
|
|
<para>If you have a lot of modules and very little space, you may want to
|
|
consider stripping and compressing the modules. For most people such compression
|
|
isn't worth the trouble, but if you're really pressed for space, then have a look at
|
|
<ulink url="http://www.linux-mips.org/archives/linux-mips/2002-04/msg00031.html"/>.</para>
|
|
|
|
<para>Kernel compilation has finished but more 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 you're
|
|
using. 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 (Application Programming Interface), 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 configuration file that was
|
|
produced by the <command>make menuconfig</command> step above. It contains all
|
|
the config selections for the kernel that was just compiled. It's 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 you unpack a package as user
|
|
<emphasis>root</emphasis> (like we did here inside chroot), the files end up
|
|
having the user and group IDs of whatever they were on the packager's computer.
|
|
This is usually not a problem for any other package you install because you
|
|
remove the source tree after the installation. But the Linux source tree is
|
|
often kept around for a long time, so there's a chance that whatever user ID
|
|
the packager used will be assigned to somebody on your machine and then that
|
|
person would have write access to the kernel source.</para>
|
|
|
|
<para>If you are going to keep the kernel source tree around, you may want to
|
|
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><title>Short descriptions</title>
|
|
|
|
<varlistentry id="kernel">
|
|
<term>The <emphasis>kernel</emphasis></term>
|
|
<listitem>
|
|
<indexterm zone="ch-bootable-kernel kernel"><primary sortas="b-kernel">kernel</primary></indexterm>
|
|
<para>is the engine of your Linux system.
|
|
When switching on your box, the kernel is the first part of your operating
|
|
system that gets loaded. It detects and initializes all the components of your
|
|
computer's hardware, then makes these components available as a tree of files
|
|
to the software, and turns a single CPU into a multi-tasking machine capable
|
|
of running scores of programs seemingly at the same time.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="kernel-headers">
|
|
<term>The <emphasis>kernel headers</emphasis></term>
|
|
<listitem>
|
|
<indexterm zone="ch-bootable-kernel kernel-headers"><primary sortas="e-kernel-headers">kernel headers</primary></indexterm>
|
|
<para>define 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 should therefore
|
|
<emphasis>not</emphasis> be replaced when upgrading the kernel.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="System.map">
|
|
<term><filename>System.map</filename></term>
|
|
<listitem>
|
|
<indexterm zone="ch-bootable-kernel System.map"><primary sortas="e-/boot/System.map">/boot/System.map</primary></indexterm>
|
|
<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>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
</sect2>
|
|
|
|
</sect1>
|