source: BOOK/bootable/x86/kernel.xml@ e979069

systemd
Last change on this file since e979069 was 31072b5, checked in by Chris Staub <chris@…>, 10 years ago

Another wording change

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1<?xml version="1.0" encoding="ISO-8859-1"?>
2<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4 <!ENTITY % general-entities SYSTEM "../../general.ent">
5 %general-entities;
6]>
7
8<sect1 id="ch-bootable-kernel" role="wrap">
9 <?dbhtml filename="kernel.html"?>
10
11 <title>Linux-&linux-version2;</title>
12
13 <indexterm zone="ch-bootable-kernel">
14 <primary sortas="a-Linux">Linux</primary>
15 </indexterm>
16
17 <sect2 role="package"><title/>
18 <para>The Linux package contains the Linux kernel.</para>
19
20 </sect2>
21
22 <sect2 role="installation">
23 <title>Installation of the kernel</title>
24
25 <para os="a">Building the kernel involves a few steps&mdash;configuration,
26 compilation, and installation. Read the <filename>README</filename>
27 file in the kernel source tree for alternative methods to the way this
28 book configures the kernel.</para>
29
30 <para os="p1">Apply the latest Linux sublevel patch:</para>
31
32<screen os="p2"><userinput>xzcat ../&linux-sublevel-patch; | patch -Np1 -i -</userinput></screen>
33
34 <para os="b">Prepare for compilation by running the following command:</para>
35
36<screen os="c"><userinput>make mrproper</userinput></screen>
37
38 <para os="d">This ensures that the kernel tree is absolutely clean. The
39 kernel team recommends that this command be issued prior to each
40 kernel compilation. Do not rely on the source tree being clean after
41 un-tarring.</para>
42
43 <note os="kc"><para>A good starting place for setting up the kernel
44 configuration is to run <command>make defconfig</command>. This will set the base configuration to a good state that takes your current system
45 architecture into account.</para>
46
47 <para>Be sure to configure the following options as
48 shown, or the system might not work correctly or boot at all.
49 Refer to <filename>/usr/share/doc/systemd-&systemd-version;/README</filename>:</para>
50
51 <screen role="nodump">General setup ---&gt;
52 [*] open by fhandle syscalls (CONFIG_FHANDLE)
53 [ ] Auditing support (CONFIG_AUDIT)
54 [*] Control Group support (CONFIG_CGROUPS)
55Processor type and features ---&gt;
56 [*] Enable seccomp to safely compute untrusted bytecode (CONFIG_SECCOMP)
57Networking support ---&gt;
58 Networking options ---&gt;
59 &lt;*&gt; The IPv6 protocol (CONFIG_IPV6)
60Device Drivers ---&gt;
61 Generic Driver Options ---&gt;
62 () path to uevent helper (CONFIG_UEVENT_HELPER_PATH)
63 [*] Maintain a devtmpfs filesystem to mount at /dev (CONFIG_DEVTMPFS)
64 [ ] Fallback user-helper invocation for firmware loading (CONFIG_FW_LOADER_USER_HELPER)
65File systems ---&gt;
66 [*] Inotify support for userspace (CONFIG_FSNOTIFY)
67 &lt;*&gt; Kernel automounter version 4 support (also supports v3) (CONFIG_AUTOFS4_FS)
68 Pseudo filesystems ---&gt;
69 [*] Tmpfs POSIX Access Control Lists (CONFIG_TMPFS_POSIX_ACL)
70 [*] Tmpfs extended attributes (CONFIG_TMPFS_XATTR)
71Firmware Drivers ---&gt;
72 EFI (Extensible Firmware Interface) Support ---&gt;
73 &lt;*&gt; EFI Variable Support via sysfs (CONFIG_EFI_VARS)
74-*- Enable the block layer ---&gt; (CONFIG_BLOCK)
75 Partition Types ---&gt;
76 [*] Advanced partition selection (CONFIG_PARTITION_ADVANCED)
77 [*] EFI GUID Partition support (CONFIG_EFI_PARTITION)
78Kernel Hacking ---&gt;
79 [*] Collect scheduler debugging info (CONFIG_SCHED_DEBUG)
80 [*] Collect scheduler statistics (CONFIG_SCHEDSTATS)</screen></note>
81
82 <note os="kd"><para>While "The IPv6 Protocol" is not strictly required, it
83 is highly recommended by the Systemd developers. "EFI Variable support" and
84 "EFI GUID Partition support" are for UEFI systems. "Collect scheduler
85 debugging info" and "Collect scheduler statistics" is for systemd-bootchart.
86 </para></note>
87
88 <para os="h">Configure the kernel via a menu-driven interface.
89 CBLFS has some information regarding particular kernel configuration
90 requirements of packages outside of CLFS at <ulink
91 url="&cblfs-root;"/>:</para>
92
93<screen os="i"><userinput>make menuconfig</userinput></screen>
94
95 <para os="j">Alternatively, <command>make oldconfig</command> may be more
96 appropriate in some situations. See the <filename>README</filename>
97 file for more information.</para>
98
99 <para os="k">If desired, skip kernel configuration by copying the kernel
100 config file, <filename>.config</filename>, from the host system
101 (assuming it is available) to the root directory of the unpacked kernel
102 sources. However, we do not recommend this option. It is often better
103 to explore all the configuration menus and create the kernel configuration
104 from scratch.</para>
105
106 <para os="m">Compile the kernel image and modules:</para>
107
108<screen os="n"><userinput>make</userinput></screen>
109
110 <para os="o">If using kernel modules, a configuration file in
111 <filename class="directory">/etc/modprobe.d</filename> file may be needed.
112 Information pertaining to modules and kernel configuration is
113 located in the kernel documentation in the <filename
114 class="directory">Documentation</filename> directory of the kernel
115 sources tree. Also, <filename>modprobe.d(5)</filename> may
116 be of interest.</para>
117
118 <para os="s">Install the modules, if the kernel configuration uses
119 them:</para>
120
121<screen os="t"><userinput>make modules_install</userinput></screen>
122
123 <para os="s2">Install the firmware, if the kernel configuration uses
124 them:</para>
125
126<screen os="t2"><userinput>make firmware_install</userinput></screen>
127
128 <para os="u">After kernel compilation is complete, additional steps are
129 required to complete the installation. Some files need to be copied to
130 the <filename class="directory">/boot</filename> directory.</para>
131
132 <para os="v">Issue the following command to install the kernel:</para>
133
134<screen><userinput>cp -v arch/i386/boot/bzImage /boot/vmlinuz-clfs-&linux-version2;</userinput></screen>
135
136 <para os="w"><filename>System.map</filename> is a symbol file for the kernel.
137 It maps the function entry points of every function in the kernel API,
138 as well as the addresses of the kernel data structures for the running
139 kernel. Issue the following command to install the map file:</para>
140
141<screen os="w1"><userinput>cp -v System.map /boot/System.map-&linux-version2;</userinput></screen>
142
143 <para os="x">The kernel configuration file <filename>.config</filename>
144 produced by the <command>make menuconfig</command> step above contains
145 all the configuration selections for the kernel that was just compiled.
146 It is a good idea to keep this file for future reference:</para>
147
148<screen os="x1"><userinput>cp -v .config /boot/config-&linux-version2;</userinput></screen>
149
150 <para os="y">It is important to note that the files in the kernel source
151 directory are not owned by <systemitem class="username">root</systemitem>.
152 Whenever a package is unpacked as user <systemitem
153 class="username">root</systemitem> (like we do inside the final-system
154 build environment), the files have the user and group IDs of whatever
155 they were on the packager's computer. This is usually not a problem
156 for any other package to be installed because the source tree is
157 removed after the installation. However, the Linux source tree is
158 often retained for a long time. Because of this, there is a chance
159 that whatever user ID the packager used will be assigned to somebody
160 on the machine. That person would then have write access to the kernel
161 source.</para>
162
163 <para os="y1">If the kernel source tree is going to retained, run
164 <command>chown -R 0:0</command> on the <filename
165 class="directory">linux-&linux-version;</filename> directory to
166 ensure all files are owned by user <systemitem
167 class="username">root</systemitem>.</para>
168
169 <warning os="z">
170 <para>Some kernel documentation recommends creating a symlink from
171 <filename class="symlink">/usr/src/linux</filename> pointing to the
172 kernel source directory. This is specific to kernels prior to the
173 2.6 series and <emphasis>must not</emphasis> be created on a CLFS
174 system as it can cause problems for packages you may wish to build
175 once your base CLFS system is complete.</para>
176
177 <para>Also, the headers in the system's <filename
178 class="directory">include</filename> directory should
179 <emphasis>always</emphasis> be the ones against which Glibc was
180 compiled and should <emphasis>never</emphasis> be replaced by headers
181 from a different kernel version.</para>
182 </warning>
183
184 </sect2>
185
186 <sect2 id="contents-kernel" role="content">
187 <title>Contents of Linux</title>
188
189 <segmentedlist>
190 <segtitle>Installed files</segtitle>
191 <segtitle>Installed directory</segtitle>
192
193 <seglistitem>
194 <seg>config-[linux-version], clfskernel-[linux-version],
195 and System.map-[linux-version]</seg>
196 <seg>/lib/modules</seg>
197 </seglistitem>
198 </segmentedlist>
199
200 <variablelist>
201 <bridgehead renderas="sect3">Short Descriptions</bridgehead>
202 <?dbfo list-presentation="list"?>
203 <?dbhtml list-presentation="table"?>
204
205 <varlistentry id="config">
206 <term><filename>config-[linux-version]</filename></term>
207 <listitem>
208 <para>Contains all the configuration selections for the kernel</para>
209 <indexterm zone="ch-bootable-kernel config">
210 <primary sortas="e-/boot/config">/boot/config-[linux-version]</primary>
211 </indexterm>
212 </listitem>
213 </varlistentry>
214
215 <varlistentry id="clfskernel">
216 <term><filename>clfskernel-[linux-version]</filename></term>
217 <listitem>
218 <para>The engine of the Linux system. When turning on the
219 computer, the kernel is the first part of the operating system
220 that gets loaded. It detects and initializes all components of
221 the computer's hardware, then makes these components available
222 as a tree of files to the software and turns a single CPU into
223 a multitasking machine capable of running scores of programs
224 seemingly at the same time.</para>
225 <indexterm zone="ch-bootable-kernel clfskernel">
226 <primary sortas="b-clfskernel">clfskernel-[linux-version]</primary>
227 </indexterm>
228 </listitem>
229 </varlistentry>
230
231 <varlistentry id="System.map">
232 <term><filename>System.map-[linux-version]</filename></term>
233 <listitem>
234 <para>A list of addresses and symbols; it maps the entry points
235 and addresses of all the functions and data structures in the
236 kernel</para>
237 <indexterm zone="ch-bootable-kernel System.map">
238 <primary sortas="e-/boot/System.map">/boot/System.map-[linux-version]</primary>
239 </indexterm>
240 </listitem>
241 </varlistentry>
242
243 </variablelist>
244
245 </sect2>
246
247</sect1>
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