Trunk is now identical to Testing

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@4648 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

1 files changed, 179 insertions, 18 deletions

diff --git a/chapter08/kernel.xml b/chapter08/kernel.xml
index 9fe3bc889..4b775a3d9 100644
--- a/chapter08/kernel.xml
+++ b/chapter08/kernel.xml
@@ -3,26 +3,37 @@
   <!ENTITY % general-entities SYSTEM "../general.ent">
   %general-entities;
 ]>
-<sect1 id="ch-bootable-kernel" xreflabel="Linux" role="wrap">
+<sect1 id="ch-bootable-kernel" 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>
+<seglistitem><seg>4.20 SBU</seg>
+<seg>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, and Sed</seg></seglistitem>
+</segmentedlist>
 </sect2>
 
 <sect2 role="installation">
 <title>Installation of the kernel</title>
 
+<para>Building the kernel involves a few steps&mdash;configuration,
+compilation, and installation. Read the <filename>README</filename>
+file in the kernel source tree for alternate methods to the way this
+book configures the kernel.</para>
+
 <para>Kernel version 2.6.10 has a security vulnerability that will allow user
 processes to gain root privledges upon loading of a kernel module.  See:
 <ulink url="http://www.uwsg.iu.edu/hypermail/linux/kernel/0412.3/0679.html"/> for more information.  The following patch fixes this problem:</para>
@@ -33,50 +44,200 @@ processes to gain root privledges upon loading of a kernel module.  See:
 
 <screen><userinput>make mrproper</userinput></screen>
 
-<!--NEW: the sed command has been removed-->
+<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>If, in <xref linkend="ch-scripts-console"/>, you decided you want
-to compile the keymap into the kernel, issue the command below:</para>
+<para>If, in <xref linkend="ch-scripts-console" role=","/> it was 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> &gt; \
     drivers/char/defkeymap.c</userinput></screen>
 
-<para>Configure the kernel via a menu-driven interface.  BLFS has some
-information regarding particular kernel configuration requirements of
-packages outside of LFS at
-<ulink url="&blfs-root;view/svn/longindex.html#kernel-config-index"/>.</para>
+<para>For example, if using a Dutch keyboard, use
+<phrase
+condition="html"><filename>/usr/share/kbd/keymaps/i386/qwerty/nl.map.gz</filename></phrase><phrase
+condition="pdf"><filename>/usr/share/kbd/keymaps/i386/
+qwerty/nl.map.gz</filename></phrase>.</para>
+
+<para>Configure the kernel via a menu-driven interface:</para>
 
 <screen><userinput>make menuconfig</userinput></screen>
 
+<para>Alternatively, <command>make oldconfig</command> may be more appropriate in some
+situations. See the <filename>README</filename> file for more
+information.</para>
+
+<note><para>When configuring 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 create 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 test suite, 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>Install the modules, if your kernel configuration uses them:</para>
+<para>If using kernel modules, an
+<filename>/etc/modprobe.conf</filename> file may be needed.
+Information pertaining to modules and 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 the one below in the
+<filename>/etc/modprobe.conf</filename> file do not work with
+Udev:</para>
+
+<para><screen>alias char-major-XXX some-module</screen></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 the kernel configuration uses them:</para>
 
 <screen><userinput>make modules_install</userinput></screen>
 
-<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>
+<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>The kernel configuration file <filename>.config</filename>
+produced by the <command>make menuconfig</command> step
+above 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>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>
+<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
+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 be 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>
+
+<warning><para>Some kernel documentation recommends creating a symlink from
+<filename class="symlink">/usr/src/linux</filename> pointing to the kernel
+source directory.  This is specific to kernels prior to the 2.6 series and
+<emphasis>must not</emphasis> be created on an LFS system as it can cause
+problems for packages you may wish to build once your base LFS system is
+complete.</para></warning>
 
 </sect2>
 
 
 <sect2 id="contents-kernel" role="content"><title>Contents of Linux</title>
 
-<para>See testing</para>
+<segmentedlist>
+<segtitle>Installed files</segtitle>
+<seglistitem><seg>kernel, kernel headers,
+and System.map</seg></seglistitem>
+</segmentedlist>
+
+<variablelist><bridgehead renderas="sect3">Short Descriptions</bridgehead>
+<?dbfo list-presentation="list"?>
+
+<varlistentry id="kernel">
+<term><filename>kernel</filename></term>
+<listitem>
+<para>The engine of the Linux system. When turning on the 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><filename>kernel headers</filename></term>
+<listitem>
+<para>Defines the interface to the services that the kernel provides.
+The headers in the 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>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>
+