source: chapter06/kernel.xml@ 56f1739

xry111/clfs-ng
Last change on this file since 56f1739 was 56f1739, checked in by Xi Ruoyao <xry111@…>, 10 months ago

cross-ng: use uncompressed kernel image in chapter 6

"vmlinux" always exists after running "make". Use it so we won't need
to change the command porting to another arch.

  • Property mode set to 100644
File size: 7.2 KB
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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-tools-kernel" role="wrap">
9 <?dbhtml filename="kernel.html"?>
10
11 <sect1info condition="script">
12 <productname>kernel</productname>
13 <productnumber>&linux-version;</productnumber>
14 <address>&linux-url;</address>
15 </sect1info>
16
17 <title>Linux-&linux-version;</title>
18
19 <indexterm zone="ch-tools-kernel">
20 <primary sortas="a-Linux">Linux</primary>
21 <secondary>tools</secondary>
22 </indexterm>
23
24 <sect2 role="package">
25 <title/>
26
27 <para>The Linux package contains the Linux kernel.</para>
28
29 <segmentedlist>
30 <segtitle>&buildtime;</segtitle>
31 <segtitle>&diskspace;</segtitle>
32
33 <seglistitem>
34 <seg>&linux-tmp-sbu;</seg>
35 <seg>&linux-tmp-du;</seg>
36 </seglistitem>
37 </segmentedlist>
38
39 </sect2>
40
41 <sect2 role="installation">
42 <title>Installation of the kernel</title>
43
44 <para>Building the kernel involves a few steps&mdash;configuration,
45 compilation, and installation. Read the <filename>README</filename> file
46 in the kernel source tree for alternative methods to the way this book
47 configures the kernel.</para>
48
49 <para>Prepare for compilation by running the following command:</para>
50
51<screen><userinput remap="pre">make mrproper</userinput></screen>
52
53 <para>This ensures that the kernel tree is absolutely clean. The
54 kernel team recommends that this command be issued prior to each
55 kernel compilation. Do not rely on the source tree being clean after
56 un-tarring.</para>
57
58 <para>There are several ways to configure the kernel options. Usually,
59 This is done through a menu-driven interface, for example:</para>
60
61<screen role="nodump"><userinput>make ARCH=<replaceable>x86</replaceable> CROSS_COMPILE=$LFS_TGT- menuconfig</userinput></screen>
62
63 <variablelist>
64 <title>The meaning of make environment variables:</title>
65
66 <varlistentry>
67 <term><command>ARCH=x86</command></term>
68 <listitem>
69 <para>Configure the kernel for running on the target machine.
70 Replace <replaceable>x86</replaceable> with a value suitable
71 for your target machine if it's not a 32-bit or 64-bit x86.</para>
72 </listitem>
73 </varlistentry>
74
75 <varlistentry>
76 <term><command>CROSS_COMPILE=$LFS_TGT-</command></term>
77 <listitem>
78 <para>Build the kernel with Binutils and GCC built in
79 <xref linkend='chapter-cross-tools'/>.</para>
80 </listitem>
81 </varlistentry>
82
83 <varlistentry>
84 <term><command>menuconfig</command></term>
85 <listitem>
86 <para>This launches an ncurses menu-driven interface. For other
87 (graphical) interfaces, type <command>make help</command>.</para>
88 </listitem>
89 </varlistentry>
90
91 <varlistentry>
92 <term>(optional) <parameter>LANG=&lt;host_LANG_value&gt; LC_ALL=</parameter></term>
93 <listitem>
94 <para>This establishes the locale setting to the one used on the
95 host. This may be needed for a proper menuconfig ncurses interface
96 line drawing on a UTF-8 linux text console.</para>
97
98 <para>If used, be sure to replace
99 <replaceable>&lt;host_LANG_value&gt;</replaceable> by the value of
100 the <envar>$LANG</envar> variable from your host. You can
101 alternatively use instead the host's value of <envar>$LC_ALL</envar>
102 or <envar>$LC_CTYPE</envar>.</para>
103 </listitem>
104 </varlistentry>
105
106 </variablelist>
107
108 <note>
109
110 <para>A good starting place for setting up the kernel configuration is to
111 run <command>make ARCH=x86 CROSS_COMPILE=$LFS_TGT- defconfig</command>. This will set the base
112 configuration to a good state that takes your target system architecture
113 into account.</para>
114
115 </note>
116
117 <para>Read <xref linkend='ch-bootable-kernel'/> for more information
118 about kernel configuration. You should enable or disable some kernel
119 configuration options now:</para>
120
121 <variablelist>
122 <title>Kernel configuration options and explanation:</title>
123
124 <varlistentry>
125 <term>Set <parameter>CONFIG_MODULES=n</parameter></term>
126 <listitem>
127 <para>Modular kernel needs <command>modprobe</command> tool from
128 <application>Kmod</application> to load modules, which is not
129 installed in the temporary system.</para>
130 </listitem>
131 </varlistentry>
132
133 <varlistentry>
134 <term>Set <parameter>CONFIG_EXTRA_FIRMWARE="<replaceable>a.bin b.bin</replaceable>"</parameter></term>
135 <listitem>
136 <para>Build firmware blobs into the kernel. Some drivers may
137 require the firmwares to be in-kernel if the driver is not built
138 as module.</para>
139 <note>
140 <para>
141 The kernel binaries with third-party blobs are not
142 distributable. If you distribute such a kernel binary to
143 others, you may violate GPL. It's recommended to remove the
144 temporary kernel image after you've successfully boot your LFS
145 system with the new kernel image, which will be installed in
146 <xref linkend="ch-bootable-kernel"/>.
147 </para>
148 </note>
149 </listitem>
150 </varlistentry>
151
152 <varlistentry>
153 <term>Set <parameter>CONFIG_EXTRA_FIRMWARE_DIR="<replaceable>$LFS</replaceable>/lib/firmware"</parameter></term>
154 <listitem>
155 <para>The building system will search
156 <filename class="directory">/lib/firmware</filename> for firmware
157 blobs in <parameter>CONFIG_EXTRA_FIRMWARE</parameter>. Note that
158 you'll need to install the needed firmwares into
159 <filename class="directory">$LFS/lib/firmware</filename> first,
160 and manually replace <envar>$LFS</envar> with the value in
161 configuration. The firmwares in
162 <filename class="directory">$LFS/lib/filename</filename> will be
163 copied to the target machine along with the system, so kernel and
164 kernel modules which will be built in
165 <xref linkend="ch-bootable-kernel"/> can load them without
166 <parameter>CONFIG_EXTRA_FIRMWARE</parameter>.</para>
167 </listitem>
168 </varlistentry>
169
170 <varlistentry>
171 <term>Enable <parameter>CONFIG_EXT2</parameter>,
172 <parameter>CONFIG_EXT4</parameter>,
173 and <parameter>CONFIG_VFAT_FS</parameter></term>
174 <listitem>
175 <para>They are needed to access the filesystems we'll make for the
176 target system.</para>
177 </listitem>
178 </varlistentry>
179 </variablelist>
180
181 <para>Compile the kernel image:</para>
182
183<screen><userinput remap="make">make ARCH=x86 CROSS_COMPILE=$LFS_TGT-</userinput></screen>
184
185 <para>Install the kernel image into the
186 <filename class="directory">$LFS/boot</filename> directory:</para>
187
188 <screen><userinput remap="install">install -vm644 vmlinux $LFS/boot/vmlinux</userinput></screen>
189
190 </sect2>
191
192 <sect2 role="content">
193 <title/>
194
195 <para>Details on this package are located in
196 <xref linkend="contents-kernel" role="."/></para>
197
198 </sect2>
199
200</sect1>
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