en/handbook/hb-install-x86+amd64-kernel.xml

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<!DOCTYPE sections SYSTEM "/dtd/book.dtd">

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<sections>

<abstract>
The Linux kernel is the core of every distribution. This chapter
explains how to configure your kernel.
</abstract>

<version>17</version>
<date>2012-04-12</date>

<section>
<title>Timezone</title>
<body>

<p>
You first need to select your timezone so that your system knows where it is
located. Look for your timezone in <path>/usr/share/zoneinfo</path>, then copy
it to <path>/etc/localtime</path>. Please avoid the
<path>/usr/share/zoneinfo/Etc/GMT*</path> timezones as their names do not
indicate the expected zones. For instance, <path>GMT-8</path> is in fact
GMT+8.
</p>

<pre caption="Setting the timezone information">
# <i>ls /usr/share/zoneinfo</i>
<comment>(Suppose you want to use Europe/Brussels)</comment>
# <i>cp /usr/share/zoneinfo/Europe/Brussels /etc/localtime</i>
<comment>(Next set the timezone)</comment>
# <i>echo "Europe/Brussels" &gt; /etc/timezone</i>
</pre>

</body>
</section>
<section>
<title>Installing the Sources</title>
<subsection>
<title>Choosing a Kernel</title>
<body>

<p>
The core around which all distributions are built is the Linux kernel. It is the
layer between the user programs and your system hardware. Gentoo provides its
users several possible kernel sources. A full listing with description is
available at the <uri link="/doc/en/gentoo-kernel.xml">Gentoo Kernel
Guide</uri>.
</p>

<p>
For <keyval id="arch"/>-based systems we have <c>gentoo-sources</c>
(kernel source patched for extra features).
</p>

<p>
Choose your kernel source and install it using <c>emerge</c>.
</p>

<pre caption="Installing a kernel source">
# <i>emerge gentoo-sources</i>
</pre>

<p>
When you take a look in <path>/usr/src</path> you should see a symlink called
<path>linux</path> pointing to your kernel source. In this case, the installed
kernel source points to <c>gentoo-sources-<keyval id="kernel-version"/></c>.
Your version may be different, so keep this in mind.
</p>

<pre caption="Viewing the kernel source symlink">
# <i>ls -l /usr/src/linux</i>
lrwxrwxrwx    1 root   root    12 Oct 13 11:04 /usr/src/linux -&gt; linux-<keyval id="kernel-version"/>
</pre>

<p>
Now it is time to configure and compile your kernel source. You can use
<c>genkernel</c> for this, which will build a generic kernel as used by the
Installation CD. We explain the "manual" configuration first though, as it is
the best way to optimize your environment.
</p>

<p>
If you want to manually configure your kernel, continue now with <uri
link="#manual">Default: Manual Configuration</uri>. If you want to use
<c>genkernel</c> you should read <uri link="#genkernel">Alternative: Using
genkernel</uri> instead.
</p>

</body>
</subsection>
</section>
<section id="manual">
<title>Default: Manual Configuration</title>
<subsection>
<title>Introduction</title>
<body>

<p>
Manually configuring a kernel is often seen as the most difficult procedure a
Linux user ever has to perform. Nothing is less true -- after configuring a
couple of kernels you don't even remember that it was difficult ;)
</p>

<p>
However, one thing <e>is</e> true: you must know your system when you start
configuring a kernel manually. Most information can be gathered by emerging
pciutils (<c>emerge pciutils</c>) which contains <c>lspci</c>. You will now
be able to  use <c>lspci</c> within the chrooted environment. You may safely
ignore any <e>pcilib</e> warnings (like pcilib: cannot open
/sys/bus/pci/devices) that <c>lspci</c> throws out. Alternatively, you can run
<c>lspci</c> from a <e>non-chrooted</e> environment. The results are the same.
You can also run <c>lsmod</c> to see what kernel modules the Installation CD
uses (it might provide you with a nice hint on what to enable).
</p>

<p>
Now go to your kernel source directory and execute <c>make menuconfig</c>. This
will fire up an ncurses-based configuration menu.
</p>

<pre caption="Invoking menuconfig">
# <i>cd /usr/src/linux</i>
# <i>make menuconfig</i>
</pre>

<p>
You will be greeted with several configuration sections. We'll first list some
options you must activate (otherwise Gentoo will not function, or not function
properly without additional tweaks).
</p>

</body>
</subsection>
<subsection>
<title>Activating Required Options</title>
<body>

<p>
Make sure that every driver that is vital to the booting of your system (such as
SCSI controller, ...) is compiled <e>in</e> the kernel and not as a module,
otherwise your system will not be able to boot completely.
</p>

</body>
<body test="func:keyval('arch')='AMD64'">

<p>
We shall then select the exact processor type. The x86_64 kernel maintainer
strongly recommends users enable MCE features so that they are able to be
notified of any hardware problems. On x86_64, these errors are not printed to
<c>dmesg</c> like on other architectures, but to <path>/dev/mcelog</path>. This
requires the <c>app-admin/mcelog</c> package. Make sure you select IA32
Emulation if you want to be able to run 32-bit programs. Gentoo will install a
multilib system (mixed 32-bit/64-bit computing) by default, so this option is
required.
</p>

<note>
If you plan to use a non-multilib profile (for a pure 64-bit system), then you
don't have to select IA32 Emulation support. However, you'll also need to follow
the <uri link="?part=1&amp;chap=6#doc_chap2_sect2">instructions</uri> for
switching to a <uri link="/doc/en/gentoo-amd64-faq.xml">non-multilib
profile</uri>, as well as choosing the correct <uri
link="?part=1&amp;chap=10#doc_chap2_sect2">bootloader</uri>.
</note>

<pre caption="Selecting processor type and features">
Processor type and features  --->
   [ ] Machine Check / overheating reporting 
   [ ]   Intel MCE Features
   [ ]   AMD MCE Features
  Processor family (AMD-Opteron/Athlon64)  --->
    ( ) Opteron/Athlon64/Hammer/K8
    ( ) Intel P4 / older Netburst based Xeon
    ( ) Core 2/newer Xeon
    ( ) Intel Atom
    ( ) Generic-x86-64
Executable file formats / Emulations  --->
   [*] IA32 Emulation
</pre>

</body>
<body test="func:keyval('arch')='x86'">

<p>
Now select the correct processor family:
</p>

<pre caption="Selecting correct processor family">
Processor type and features ---&gt;
  <comment>(Change according to your system)</comment>
  (<i>Athlon/Duron/K7</i>) Processor family
</pre>

</body>
<body>

<p>
Next select <e>Maintain a devtmpfs file system to mount at /dev</e> so that
critical device files are already available early in the boot process.
</p>

<pre caption="Enabling devtmpfs support">
Device Drivers ---&gt;
  Generic Driver Options ---&gt;
    [*] Maintain a devtmpfs filesystem to mount at /dev
    [ ]   Automount devtmpfs at /dev, after the kernel mounted the rootfs
</pre>

<p>
Now go to <c>File Systems</c> and select support for the filesystems you use.
<e>Don't</e> compile them as modules, otherwise your Gentoo system will not be
able to mount your partitions. Also select <c>Virtual memory</c> and <c>/proc
file system</c>.
</p>

<pre caption="Selecting necessary file systems">
File systems ---&gt;
<comment>(Select one or more of the following options as needed by your system)</comment>
  &lt;*&gt; Second extended fs support
  &lt;*&gt; Ext3 journalling file system support
  &lt;*&gt; The Extended 4 (ext4) filesystem
  &lt;*&gt; Reiserfs support
  &lt;*&gt; JFS filesystem support
  &lt;*&gt; XFS filesystem support
  ...
  Pseudo Filesystems ---&gt;
    [*] /proc file system support
    [*] Virtual memory file system support (former shm fs)

<comment>(Enable GPT partition label support if you used that previously)</comment>
  Partition Types ---&gt;
    [*] Advanced partition selection
      ...
      [*] EFI GUID Partition support
</pre>

<p>
If you are using PPPoE to connect to the Internet or you are using a dial-up
modem, you will need the following options in the kernel:
</p>

<pre caption="Selecting PPPoE necessary drivers">
Device Drivers ---&gt;
  Network device support ---&gt;
    &lt;*&gt; PPP (point-to-point protocol) support
    &lt;*&gt;   PPP support for async serial ports
    &lt;*&gt;   PPP support for sync tty ports
</pre>

<p>
The two compression options won't harm but are not definitely needed, neither
does the <c>PPP over Ethernet</c> option, that might only be used by <c>ppp</c>
when configured to do kernel mode PPPoE.
</p>

<p>
If you require it, don't forget to include support in the kernel for your
ethernet card.
</p>

<p test="func:keyval('arch')='x86'">
If you have an Intel CPU that supports HyperThreading (tm), or you have a
multi-CPU system, you should activate "Symmetric multi-processing support":
</p>

<p test="func:keyval('arch')='AMD64'">
If you have a multi-CPU Opteron or a multi-core (e.g. AMD64 X2) system, you
should activate "Symmetric multi-processing support":
</p>

<pre caption="Activating SMP support">
Processor type and features  ---&gt;
  [*] Symmetric multi-processing support
</pre>

<note>
In multi-core systems, each core counts as one processor.
</note>

<p test="func:keyval('arch')='x86'">
If you have more than 4GB of RAM, you need to enable "High Memory Support
(64G)".
</p>

<p>
If you use USB Input Devices (like Keyboard or Mouse) don't forget to enable
those as well:
</p>

<pre caption="Activating USB Support for Input Devices">
Device Drivers ---&gt;
  [*] HID Devices  ---&gt;
    &lt;*&gt;   USB Human Interface Device (full HID) support
</pre>

</body>
<body test="func:keyval('arch')='x86'">

<p>
If you want PCMCIA support for your laptop, don't forget to enable
support for the PCMCIA card bridge present in your system:
</p>

<pre caption="Enabling PCMCIA support">
Bus options (PCI etc.)  ---&gt;
  PCCARD (PCMCIA/CardBus) support  ---&gt;
    &lt;*&gt; PCCard (PCMCIA/CardBus) support
<comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
    &lt;*&gt;   16-bit PCMCIA support
    [*]   32-bit CardBus support
<comment>(select the relevant bridges below)</comment>
    *** PC-card bridges ***
    &lt;*&gt; CardBus yenta-compatible bridge support (NEW)
    &lt;*&gt; Cirrus PD6729 compatible bridge support (NEW)
    &lt;*&gt; i82092 compatible bridge support (NEW)
</pre>

<p>
When you've finished configuring the kernel, continue with <uri
link="#compiling">Compiling and Installing</uri>.
</p>

</body>
</subsection>
<subsection id="compiling">
<title>Compiling and Installing</title>
<body>

<p>
Now that your kernel is configured, it is time to compile and install it. Exit
the configuration and start the compilation process:
</p>

<pre caption="Compiling the kernel">
# <i>make &amp;&amp; make modules_install</i>
</pre>

<p>
When the kernel has finished compiling, copy the kernel image to
<path>/boot</path>. Use whatever name you feel is appropriate for your kernel
choice and remember it as you will need it later on when you configure your
bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
name and version of your kernel.
</p>

<pre caption="Installing the kernel">
# <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
</pre>

</body>
</subsection>
<subsection id="initramfs">
<title>(Optional) Building an Initramfs</title>
<body>

<p>
If you use a specific partition layout where important file system locations
(like <path>/usr</path> or <path>/var</path>) are on separate partitions, then
you will need to setup an initramfs so that this partition can be mounted before
it is needed.
</p>

<p>
Without an initramfs, you risk that the system will not boot up properly as the
tools that are responsible for mounting the file systems need information that
resides on those file systems. An initramfs will pull in the necessary files
into an archive which is used right after the kernel boots, but before the
control is handed over to the <c>init</c> tool. Scripts on the initramfs will
then make sure that the partitions are properly mounted before the system
continues booting.
</p>

<p>
To install an initramfs, install <c>genkernel</c> first, then have it 
generate an initramfs for you.
</p>

<pre caption="Building an initramfs">
# <i>emerge genkernel</i>
# <i>genkernel --install initramfs</i>
</pre>

<p>
If you need specific support in the initramfs, such as lvm or raid, add in the
appropriate options to genkernel. See <c>genkernel --help</c> for more
information, or the next example which enables support for LVM and software raid
(mdadm):
</p>

<pre caption="Building an initramfs with support for LVM and software raid">
# <i>genkernel --lvm --mdadm --install initramfs</i>
</pre>

<p>
The initramfs will be stored in <path>/boot</path>. You can find the file by
simply listing the files starting with <path>initramfs</path>:
</p>

<pre caption="Checking the initramfs file name">
# <i>ls /boot/initramfs*</i>
</pre>

<p>
Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
</p>

</body>
</subsection>
</section>
<section id="genkernel">
<title>Alternative: Using genkernel</title>
<body>

<p>
If you are reading this section, you have chosen to use our <c>genkernel</c>
script to configure your kernel for you.
</p>

<p>
Now that your kernel source tree is installed, it's now time to compile your
kernel by using our <c>genkernel</c> script to automatically build a kernel for
you. <c>genkernel</c> works by configuring a kernel nearly identically to the
way our Installation CD kernel is configured. This means that when you use
<c>genkernel</c> to build your kernel, your system will generally detect all
your hardware at boot-time, just like our Installation CD does. Because
genkernel doesn't require any manual kernel configuration, it is an ideal
solution for those users who may not be comfortable compiling their own kernels.
</p>

<p>
Now, let's see how to use genkernel. First, emerge the genkernel ebuild:
</p>

<pre caption="Emerging genkernel">
# <i>emerge genkernel</i>
</pre>

<p>
Now, compile your kernel sources by running <c>genkernel all</c>. Be aware
though, as <c>genkernel</c> compiles a kernel that supports almost all
hardware, this compilation will take quite a while to finish!
</p>

<p>
Note that, if your boot partition doesn't use ext2 or ext3 as filesystem you
might need to manually configure your kernel using <c>genkernel --menuconfig
all</c> and add support for your filesystem <e>in</e> the kernel (i.e.
<e>not</e> as a module). Users of LVM2 will probably want to add <c>--lvm2</c>
as an argument as well.
</p>

<pre caption="Running genkernel">
# <i>genkernel all</i>
</pre>

<p>
Once <c>genkernel</c> completes, a kernel, full set of modules and
<e>initial ram disk</e> (initramfs) will be created. We will use the kernel
and initrd when configuring a boot loader later in this document. Write
down the names of the kernel and initrd as you will need it when writing
the bootloader configuration file. The initrd will be started immediately after
booting to perform hardware autodetection (just like on the Installation CD)
before your "real" system starts up.
</p>

<pre caption="Checking the created kernel image name and initrd">
# <i>ls /boot/kernel* /boot/initramfs*</i>
</pre>

</body>
</section>
<section id="kernel_modules">
<title>Kernel Modules</title>

<subsection>
<include href="hb-install-kernelmodules.xml"/>
</subsection>

</section>
</sections>
1	<?xml version='1.0' encoding='UTF-8'?>
2	<!DOCTYPE sections SYSTEM "/dtd/book.dtd">
3
4	<!-- The content of this document is licensed under the CC-BY-SA license -->
5	<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
6
7	<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-install-x86+amd64-kernel.xml,v 1.46 2012/03/27 17:47:19 swift Exp $ -->
8
9	<sections>
10
11	<abstract>
12	The Linux kernel is the core of every distribution. This chapter
13	explains how to configure your kernel.
14	</abstract>
15
16	<version>17</version>
17	<date>2012-04-12</date>
18
19	<section>
20	<title>Timezone</title>
21	<body>
22
23	<p>
24	You first need to select your timezone so that your system knows where it is
25	located. Look for your timezone in <path>/usr/share/zoneinfo</path>, then copy
26	it to <path>/etc/localtime</path>. Please avoid the
27	<path>/usr/share/zoneinfo/Etc/GMT*</path> timezones as their names do not
28	indicate the expected zones. For instance, <path>GMT-8</path> is in fact
29	GMT+8.
30	</p>
31
32	<pre caption="Setting the timezone information">
33	# <i>ls /usr/share/zoneinfo</i>
34	<comment>(Suppose you want to use Europe/Brussels)</comment>
35	# <i>cp /usr/share/zoneinfo/Europe/Brussels /etc/localtime</i>
36	<comment>(Next set the timezone)</comment>
37	# <i>echo "Europe/Brussels" > /etc/timezone</i>
38	</pre>
39
40	</body>
41	</section>
42	<section>
43	<title>Installing the Sources</title>
44	<subsection>
45	<title>Choosing a Kernel</title>
46	<body>
47
48	<p>
49	The core around which all distributions are built is the Linux kernel. It is the
50	layer between the user programs and your system hardware. Gentoo provides its
51	users several possible kernel sources. A full listing with description is
52	available at the <uri link="/doc/en/gentoo-kernel.xml">Gentoo Kernel
53	Guide</uri>.
54	</p>
55
56	<p>
57	For <keyval id="arch"/>-based systems we have <c>gentoo-sources</c>
58	(kernel source patched for extra features).
59	</p>
60
61	<p>
62	Choose your kernel source and install it using <c>emerge</c>.
63	</p>
64
65	<pre caption="Installing a kernel source">
66	# <i>emerge gentoo-sources</i>
67	</pre>
68
69	<p>
70	When you take a look in <path>/usr/src</path> you should see a symlink called
71	<path>linux</path> pointing to your kernel source. In this case, the installed
72	kernel source points to <c>gentoo-sources-<keyval id="kernel-version"/></c>.
73	Your version may be different, so keep this in mind.
74	</p>
75
76	<pre caption="Viewing the kernel source symlink">
77	# <i>ls -l /usr/src/linux</i>
78	lrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -> linux-<keyval id="kernel-version"/>
79	</pre>
80
81	<p>
82	Now it is time to configure and compile your kernel source. You can use
83	<c>genkernel</c> for this, which will build a generic kernel as used by the
84	Installation CD. We explain the "manual" configuration first though, as it is
85	the best way to optimize your environment.
86	</p>
87
88	<p>
89	If you want to manually configure your kernel, continue now with <uri
90	link="#manual">Default: Manual Configuration</uri>. If you want to use
91	<c>genkernel</c> you should read <uri link="#genkernel">Alternative: Using
92	genkernel</uri> instead.
93	</p>
94
95	</body>
96	</subsection>
97	</section>
98	<section id="manual">
99	<title>Default: Manual Configuration</title>
100	<subsection>
101	<title>Introduction</title>
102	<body>
103
104	<p>
105	Manually configuring a kernel is often seen as the most difficult procedure a
106	Linux user ever has to perform. Nothing is less true -- after configuring a
107	couple of kernels you don't even remember that it was difficult ;)
108	</p>
109
110	<p>
111	However, one thing <e>is</e> true: you must know your system when you start
112	configuring a kernel manually. Most information can be gathered by emerging
113	pciutils (<c>emerge pciutils</c>) which contains <c>lspci</c>. You will now
114	be able to use <c>lspci</c> within the chrooted environment. You may safely
115	ignore any <e>pcilib</e> warnings (like pcilib: cannot open
116	/sys/bus/pci/devices) that <c>lspci</c> throws out. Alternatively, you can run
117	<c>lspci</c> from a <e>non-chrooted</e> environment. The results are the same.
118	You can also run <c>lsmod</c> to see what kernel modules the Installation CD
119	uses (it might provide you with a nice hint on what to enable).
120	</p>
121
122	<p>
123	Now go to your kernel source directory and execute <c>make menuconfig</c>. This
124	will fire up an ncurses-based configuration menu.
125	</p>
126
127	<pre caption="Invoking menuconfig">
128	# <i>cd /usr/src/linux</i>
129	# <i>make menuconfig</i>
130	</pre>
131
132	<p>
133	You will be greeted with several configuration sections. We'll first list some
134	options you must activate (otherwise Gentoo will not function, or not function
135	properly without additional tweaks).
136	</p>
137
138	</body>
139	</subsection>
140	<subsection>
141	<title>Activating Required Options</title>
142	<body>
143
144	<p>
145	Make sure that every driver that is vital to the booting of your system (such as
146	SCSI controller, ...) is compiled <e>in</e> the kernel and not as a module,
147	otherwise your system will not be able to boot completely.
148	</p>
149
150	</body>
151	<body test="func:keyval('arch')='AMD64'">
152
153	<p>
154	We shall then select the exact processor type. The x86_64 kernel maintainer
155	strongly recommends users enable MCE features so that they are able to be
156	notified of any hardware problems. On x86_64, these errors are not printed to
157	<c>dmesg</c> like on other architectures, but to <path>/dev/mcelog</path>. This
158	requires the <c>app-admin/mcelog</c> package. Make sure you select IA32
159	Emulation if you want to be able to run 32-bit programs. Gentoo will install a
160	multilib system (mixed 32-bit/64-bit computing) by default, so this option is
161	required.
162	</p>
163
164	<note>
165	If you plan to use a non-multilib profile (for a pure 64-bit system), then you
166	don't have to select IA32 Emulation support. However, you'll also need to follow
167	the <uri link="?part=1&chap=6#doc_chap2_sect2">instructions</uri> for
168	switching to a <uri link="/doc/en/gentoo-amd64-faq.xml">non-multilib
169	profile</uri>, as well as choosing the correct <uri
170	link="?part=1&chap=10#doc_chap2_sect2">bootloader</uri>.
171	</note>
172
173	<pre caption="Selecting processor type and features">
174	Processor type and features --->
175	[ ] Machine Check / overheating reporting
176	[ ] Intel MCE Features
177	[ ] AMD MCE Features
178	Processor family (AMD-Opteron/Athlon64) --->
179	( ) Opteron/Athlon64/Hammer/K8
180	( ) Intel P4 / older Netburst based Xeon
181	( ) Core 2/newer Xeon
182	( ) Intel Atom
183	( ) Generic-x86-64
184	Executable file formats / Emulations --->
185	[*] IA32 Emulation
186	</pre>
187
188	</body>
189	<body test="func:keyval('arch')='x86'">
190
191	<p>
192	Now select the correct processor family:
193	</p>
194
195	<pre caption="Selecting correct processor family">
196	Processor type and features --->
197	<comment>(Change according to your system)</comment>
198	(<i>Athlon/Duron/K7</i>) Processor family
199	</pre>
200
201	</body>
202	<body>
203
204	<p>
205	Next select <e>Maintain a devtmpfs file system to mount at /dev</e> so that
206	critical device files are already available early in the boot process.
207	</p>
208
209	<pre caption="Enabling devtmpfs support">
210	Device Drivers --->
211	Generic Driver Options --->
212	[*] Maintain a devtmpfs filesystem to mount at /dev
213	[ ] Automount devtmpfs at /dev, after the kernel mounted the rootfs
214	</pre>
215
216	<p>
217	Now go to <c>File Systems</c> and select support for the filesystems you use.
218	<e>Don't</e> compile them as modules, otherwise your Gentoo system will not be
219	able to mount your partitions. Also select <c>Virtual memory</c> and <c>/proc
220	file system</c>.
221	</p>
222
223	<pre caption="Selecting necessary file systems">
224	File systems --->
225	<comment>(Select one or more of the following options as needed by your system)</comment>
226	<*> Second extended fs support
227	<*> Ext3 journalling file system support
228	<*> The Extended 4 (ext4) filesystem
229	<*> Reiserfs support
230	<*> JFS filesystem support
231	<*> XFS filesystem support
232	...
233	Pseudo Filesystems --->
234	[*] /proc file system support
235	[*] Virtual memory file system support (former shm fs)
236
237	<comment>(Enable GPT partition label support if you used that previously)</comment>
238	Partition Types --->
239	[*] Advanced partition selection
240	...
241	[*] EFI GUID Partition support
242	</pre>
243
244	<p>
245	If you are using PPPoE to connect to the Internet or you are using a dial-up
246	modem, you will need the following options in the kernel:
247	</p>
248
249	<pre caption="Selecting PPPoE necessary drivers">
250	Device Drivers --->
251	Network device support --->
252	<*> PPP (point-to-point protocol) support
253	<*> PPP support for async serial ports
254	<*> PPP support for sync tty ports
255	</pre>
256
257	<p>
258	The two compression options won't harm but are not definitely needed, neither
259	does the <c>PPP over Ethernet</c> option, that might only be used by <c>ppp</c>
260	when configured to do kernel mode PPPoE.
261	</p>
262
263	<p>
264	If you require it, don't forget to include support in the kernel for your
265	ethernet card.
266	</p>
267
268	<p test="func:keyval('arch')='x86'">
269	If you have an Intel CPU that supports HyperThreading (tm), or you have a
270	multi-CPU system, you should activate "Symmetric multi-processing support":
271	</p>
272
273	<p test="func:keyval('arch')='AMD64'">
274	If you have a multi-CPU Opteron or a multi-core (e.g. AMD64 X2) system, you
275	should activate "Symmetric multi-processing support":
276	</p>
277
278	<pre caption="Activating SMP support">
279	Processor type and features --->
280	[*] Symmetric multi-processing support
281	</pre>
282
283	<note>
284	In multi-core systems, each core counts as one processor.
285	</note>
286
287	<p test="func:keyval('arch')='x86'">
288	If you have more than 4GB of RAM, you need to enable "High Memory Support
289	(64G)".
290	</p>
291
292	<p>
293	If you use USB Input Devices (like Keyboard or Mouse) don't forget to enable
294	those as well:
295	</p>
296
297	<pre caption="Activating USB Support for Input Devices">
298	Device Drivers --->
299	[*] HID Devices --->
300	<*> USB Human Interface Device (full HID) support
301	</pre>
302
303	</body>
304	<body test="func:keyval('arch')='x86'">
305
306	<p>
307	If you want PCMCIA support for your laptop, don't forget to enable
308	support for the PCMCIA card bridge present in your system:
309	</p>
310
311	<pre caption="Enabling PCMCIA support">
312	Bus options (PCI etc.) --->
313	PCCARD (PCMCIA/CardBus) support --->
314	<*> PCCard (PCMCIA/CardBus) support
315	<comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
316	<*> 16-bit PCMCIA support
317	[*] 32-bit CardBus support
318	<comment>(select the relevant bridges below)</comment>
319	* PC-card bridges *
320	<*> CardBus yenta-compatible bridge support (NEW)
321	<*> Cirrus PD6729 compatible bridge support (NEW)
322	<*> i82092 compatible bridge support (NEW)
323	</pre>
324
325	<p>
326	When you've finished configuring the kernel, continue with <uri
327	link="#compiling">Compiling and Installing</uri>.
328	</p>
329
330	</body>
331	</subsection>
332	<subsection id="compiling">
333	<title>Compiling and Installing</title>
334	<body>
335
336	<p>
337	Now that your kernel is configured, it is time to compile and install it. Exit
338	the configuration and start the compilation process:
339	</p>
340
341	<pre caption="Compiling the kernel">
342	# <i>make && make modules_install</i>
343	</pre>
344
345	<p>
346	When the kernel has finished compiling, copy the kernel image to
347	<path>/boot</path>. Use whatever name you feel is appropriate for your kernel
348	choice and remember it as you will need it later on when you configure your
349	bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
350	name and version of your kernel.
351	</p>
352
353	<pre caption="Installing the kernel">
354	# <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
355	</pre>
356
357	</body>
358	</subsection>
359	<subsection id="initramfs">
360	<title>(Optional) Building an Initramfs</title>
361	<body>
362
363	<p>
364	If you use a specific partition layout where important file system locations
365	(like <path>/usr</path> or <path>/var</path>) are on separate partitions, then
366	you will need to setup an initramfs so that this partition can be mounted before
367	it is needed.
368	</p>
369
370	<p>
371	Without an initramfs, you risk that the system will not boot up properly as the
372	tools that are responsible for mounting the file systems need information that
373	resides on those file systems. An initramfs will pull in the necessary files
374	into an archive which is used right after the kernel boots, but before the
375	control is handed over to the <c>init</c> tool. Scripts on the initramfs will
376	then make sure that the partitions are properly mounted before the system
377	continues booting.
378	</p>
379
380	<p>
381	To install an initramfs, install <c>genkernel</c> first, then have it
382	generate an initramfs for you.
383	</p>
384
385	<pre caption="Building an initramfs">
386	# <i>emerge genkernel</i>
387	# <i>genkernel --install initramfs</i>
388	</pre>
389
390	<p>
391	If you need specific support in the initramfs, such as lvm or raid, add in the
392	appropriate options to genkernel. See <c>genkernel --help</c> for more
393	information, or the next example which enables support for LVM and software raid
394	(mdadm):
395	</p>
396
397	<pre caption="Building an initramfs with support for LVM and software raid">
398	# <i>genkernel --lvm --mdadm --install initramfs</i>
399	</pre>
400
401	<p>
402	The initramfs will be stored in <path>/boot</path>. You can find the file by
403	simply listing the files starting with <path>initramfs</path>:
404	</p>
405
406	<pre caption="Checking the initramfs file name">
407	# <i>ls /boot/initramfs*</i>
408	</pre>
409
410	<p>
411	Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
412	</p>
413
414	</body>
415	</subsection>
416	</section>
417	<section id="genkernel">
418	<title>Alternative: Using genkernel</title>
419	<body>
420
421	<p>
422	If you are reading this section, you have chosen to use our <c>genkernel</c>
423	script to configure your kernel for you.
424	</p>
425
426	<p>
427	Now that your kernel source tree is installed, it's now time to compile your
428	kernel by using our <c>genkernel</c> script to automatically build a kernel for
429	you. <c>genkernel</c> works by configuring a kernel nearly identically to the
430	way our Installation CD kernel is configured. This means that when you use
431	<c>genkernel</c> to build your kernel, your system will generally detect all
432	your hardware at boot-time, just like our Installation CD does. Because
433	genkernel doesn't require any manual kernel configuration, it is an ideal
434	solution for those users who may not be comfortable compiling their own kernels.
435	</p>
436
437	<p>
438	Now, let's see how to use genkernel. First, emerge the genkernel ebuild:
439	</p>
440
441	<pre caption="Emerging genkernel">
442	# <i>emerge genkernel</i>
443	</pre>
444
445	<p>
446	Now, compile your kernel sources by running <c>genkernel all</c>. Be aware
447	though, as <c>genkernel</c> compiles a kernel that supports almost all
448	hardware, this compilation will take quite a while to finish!
449	</p>
450
451	<p>
452	Note that, if your boot partition doesn't use ext2 or ext3 as filesystem you
453	might need to manually configure your kernel using <c>genkernel --menuconfig
454	all</c> and add support for your filesystem <e>in</e> the kernel (i.e.
455	<e>not</e> as a module). Users of LVM2 will probably want to add <c>--lvm2</c>
456	as an argument as well.
457	</p>
458
459	<pre caption="Running genkernel">
460	# <i>genkernel all</i>
461	</pre>
462
463	<p>
464	Once <c>genkernel</c> completes, a kernel, full set of modules and
465	<e>initial ram disk</e> (initramfs) will be created. We will use the kernel
466	and initrd when configuring a boot loader later in this document. Write
467	down the names of the kernel and initrd as you will need it when writing
468	the bootloader configuration file. The initrd will be started immediately after
469	booting to perform hardware autodetection (just like on the Installation CD)
470	before your "real" system starts up.
471	</p>
472
473	<pre caption="Checking the created kernel image name and initrd">
474	# <i>ls /boot/kernel* /boot/initramfs*</i>
475	</pre>
476
477	</body>
478	</section>
479	<section id="kernel_modules">
480	<title>Kernel Modules</title>
481
482	<subsection>
483	<include href="hb-install-kernelmodules.xml"/>
484	</subsection>
485
486	</section>
487	</sections>