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Remove duplicate kernel configuration as per bug #388299. Thanks to Tupone Alfredo for reporting it

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 1.43 2011/09/26 23:02:43 nightmorph 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>14</version>
17 <date>2011-11-05</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 GMT)</comment>
35 # <i>cp /usr/share/zoneinfo/GMT /etc/localtime</i>
36 </pre>
37
38 </body>
39 </section>
40 <section>
41 <title>Installing the Sources</title>
42 <subsection>
43 <title>Choosing a Kernel</title>
44 <body>
45
46 <p>
47 The core around which all distributions are built is the Linux kernel. It is the
48 layer between the user programs and your system hardware. Gentoo provides its
49 users several possible kernel sources. A full listing with description is
50 available at the <uri link="/doc/en/gentoo-kernel.xml">Gentoo Kernel
51 Guide</uri>.
52 </p>
53
54 <p>
55 For <keyval id="arch"/>-based systems we have <c>gentoo-sources</c>
56 (kernel source patched for extra features).
57 </p>
58
59 <p>
60 Choose your kernel source and install it using <c>emerge</c>.
61 </p>
62
63 <pre caption="Installing a kernel source">
64 # <i>emerge gentoo-sources</i>
65 </pre>
66
67 <p>
68 When you take a look in <path>/usr/src</path> you should see a symlink called
69 <path>linux</path> pointing to your kernel source. In this case, the installed
70 kernel source points to <c>gentoo-sources-<keyval id="kernel-version"/></c>.
71 Your version may be different, so keep this in mind.
72 </p>
73
74 <pre caption="Viewing the kernel source symlink">
75 # <i>ls -l /usr/src/linux</i>
76 lrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -&gt; linux-<keyval id="kernel-version"/>
77 </pre>
78
79 <p>
80 Now it is time to configure and compile your kernel source. You can use
81 <c>genkernel</c> for this, which will build a generic kernel as used by the
82 Installation CD. We explain the "manual" configuration first though, as it is
83 the best way to optimize your environment.
84 </p>
85
86 <p>
87 If you want to manually configure your kernel, continue now with <uri
88 link="#manual">Default: Manual Configuration</uri>. If you want to use
89 <c>genkernel</c> you should read <uri link="#genkernel">Alternative: Using
90 genkernel</uri> instead.
91 </p>
92
93 </body>
94 </subsection>
95 </section>
96 <section id="manual">
97 <title>Default: Manual Configuration</title>
98 <subsection>
99 <title>Introduction</title>
100 <body>
101
102 <p>
103 Manually configuring a kernel is often seen as the most difficult procedure a
104 Linux user ever has to perform. Nothing is less true -- after configuring a
105 couple of kernels you don't even remember that it was difficult ;)
106 </p>
107
108 <p>
109 However, one thing <e>is</e> true: you must know your system when you start
110 configuring a kernel manually. Most information can be gathered by emerging
111 pciutils (<c>emerge pciutils</c>) which contains <c>lspci</c>. You will now
112 be able to use <c>lspci</c> within the chrooted environment. You may safely
113 ignore any <e>pcilib</e> warnings (like pcilib: cannot open
114 /sys/bus/pci/devices) that <c>lspci</c> throws out. Alternatively, you can run
115 <c>lspci</c> from a <e>non-chrooted</e> environment. The results are the same.
116 You can also run <c>lsmod</c> to see what kernel modules the Installation CD
117 uses (it might provide you with a nice hint on what to enable).
118 </p>
119
120 <p>
121 Now go to your kernel source directory and execute <c>make menuconfig</c>. This
122 will fire up an ncurses-based configuration menu.
123 </p>
124
125 <pre caption="Invoking menuconfig">
126 # <i>cd /usr/src/linux</i>
127 # <i>make menuconfig</i>
128 </pre>
129
130 <p>
131 You will be greeted with several configuration sections. We'll first list some
132 options you must activate (otherwise Gentoo will not function, or not function
133 properly without additional tweaks).
134 </p>
135
136 </body>
137 </subsection>
138 <subsection>
139 <title>Activating Required Options</title>
140 <body>
141
142 <p>
143 Make sure that every driver that is vital to the booting of your system (such as
144 SCSI controller, ...) is compiled <e>in</e> the kernel and not as a module,
145 otherwise your system will not be able to boot completely.
146 </p>
147
148 </body>
149 <body test="func:keyval('arch')='AMD64'">
150
151 <p>
152 We shall then select the exact processor type. The x86_64 kernel maintainer
153 strongly recommends users enable MCE features so that they are able to be
154 notified of any hardware problems. On x86_64, these errors are not printed to
155 <c>dmesg</c> like on other architectures, but to <path>/dev/mcelog</path>. This
156 requires the <c>app-admin/mcelog</c> package. Make sure you select IA32
157 Emulation if you want to be able to run 32-bit programs. Gentoo will install a
158 multilib system (mixed 32-bit/64-bit computing) by default, so this option is
159 required.
160 </p>
161
162 <note>
163 If you plan to use a non-multilib profile (for a pure 64-bit system), then you
164 don't have to select IA32 Emulation support. However, you'll also need to follow
165 the <uri link="?part=1&amp;chap=6#doc_chap2_sect2">instructions</uri> for
166 switching to a <uri link="/doc/en/gentoo-amd64-faq.xml">non-multilib
167 profile</uri>, as well as choosing the correct <uri
168 link="?part=1&amp;chap=10#doc_chap2_sect2">bootloader</uri>.
169 </note>
170
171 <pre caption="Selecting processor type and features">
172 Processor type and features --->
173 [ ] Machine Check / overheating reporting
174 [ ] Intel MCE Features
175 [ ] AMD MCE Features
176 Processor family (AMD-Opteron/Athlon64) --->
177 ( ) Opteron/Athlon64/Hammer/K8
178 ( ) Intel P4 / older Netburst based Xeon
179 ( ) Core 2/newer Xeon
180 ( ) Intel Atom
181 ( ) Generic-x86-64
182 Executable file formats / Emulations --->
183 [*] IA32 Emulation
184 </pre>
185
186 </body>
187 <body test="func:keyval('arch')='x86'">
188
189 <p>
190 Now select the correct processor family:
191 </p>
192
193 <pre caption="Selecting correct processor family">
194 Processor type and features ---&gt;
195 <comment>(Change according to your system)</comment>
196 (<i>Athlon/Duron/K7</i>) Processor family
197 </pre>
198
199 </body>
200 <body>
201
202 <p>
203 Now go to <c>File Systems</c> and select support for the filesystems you use.
204 <e>Don't</e> compile them as modules, otherwise your Gentoo system will not be
205 able to mount your partitions. Also select <c>Virtual memory</c> and <c>/proc
206 file system</c>.
207 </p>
208
209 <pre caption="Selecting necessary file systems">
210 File systems ---&gt;
211 <comment>(Select one or more of the following options as needed by your system)</comment>
212 &lt;*&gt; Second extended fs support
213 &lt;*&gt; Ext3 journalling file system support
214 &lt;*&gt; The Extended 4 (ext4) filesystem
215 &lt;*&gt; Reiserfs support
216 &lt;*&gt; JFS filesystem support
217 &lt;*&gt; XFS filesystem support
218 ...
219 Pseudo Filesystems ---&gt;
220 [*] /proc file system support
221 [*] Virtual memory file system support (former shm fs)
222
223 <comment>(Enable GPT partition label support if you used that previously)</comment>
224 Partition Types ---&gt;
225 [*] Advanced partition selection
226 ...
227 [*] EFI GUID Partition support
228 </pre>
229
230 <p>
231 If you are using PPPoE to connect to the Internet or you are using a dial-up
232 modem, you will need the following options in the kernel:
233 </p>
234
235 <pre caption="Selecting PPPoE necessary drivers">
236 Device Drivers ---&gt;
237 Networking device Support ---&gt;
238 &lt;*&gt; PPP (point-to-point protocol) support
239 &lt;*&gt; PPP support for async serial ports
240 &lt;*&gt; PPP support for sync tty ports
241 </pre>
242
243 <p>
244 The two compression options won't harm but are not definitely needed, neither
245 does the <c>PPP over Ethernet</c> option, that might only be used by <c>ppp</c>
246 when configured to do kernel mode PPPoE.
247 </p>
248
249 <p>
250 If you require it, don't forget to include support in the kernel for your
251 ethernet card.
252 </p>
253
254 <p test="func:keyval('arch')='x86'">
255 If you have an Intel CPU that supports HyperThreading (tm), or you have a
256 multi-CPU system, you should activate "Symmetric multi-processing support":
257 </p>
258
259 <p test="func:keyval('arch')='AMD64'">
260 If you have a multi-CPU Opteron or a multi-core (e.g. AMD64 X2) system, you
261 should activate "Symmetric multi-processing support":
262 </p>
263
264 <pre caption="Activating SMP support">
265 Processor type and features ---&gt;
266 [*] Symmetric multi-processing support
267 </pre>
268
269 <note>
270 In multi-core systems, each core counts as one processor.
271 </note>
272
273 <p test="func:keyval('arch')='x86'">
274 If you have more than 4GB of RAM, you need to enable "High Memory Support
275 (64G)".
276 </p>
277
278 <p>
279 If you use USB Input Devices (like Keyboard or Mouse) don't forget to enable
280 those as well:
281 </p>
282
283 <pre caption="Activating USB Support for Input Devices">
284 Device Drivers ---&gt;
285 [*] HID Devices ---&gt;
286 &lt;*&gt; USB Human Interface Device (full HID) support
287 </pre>
288
289 </body>
290 <body test="func:keyval('arch')='x86'">
291
292 <p>
293 If you want PCMCIA support for your laptop, don't forget to enable
294 support for the PCMCIA card bridge present in your system:
295 </p>
296
297 <pre caption="Enabling PCMCIA support">
298 Bus options (PCI etc.) ---&gt;
299 PCCARD (PCMCIA/CardBus) support ---&gt;
300 &lt;*&gt; PCCard (PCMCIA/CardBus) support
301 <comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
302 &lt;*&gt; 16-bit PCMCIA support
303 [*] 32-bit CardBus support
304 <comment>(select the relevant bridges below)</comment>
305 *** PC-card bridges ***
306 &lt;*&gt; CardBus yenta-compatible bridge support (NEW)
307 &lt;*&gt; Cirrus PD6729 compatible bridge support (NEW)
308 &lt;*&gt; i82092 compatible bridge support (NEW)
309 </pre>
310
311 <p>
312 When you've finished configuring the kernel, continue with <uri
313 link="#compiling">Compiling and Installing</uri>.
314 </p>
315
316 </body>
317 </subsection>
318 <subsection id="compiling">
319 <title>Compiling and Installing</title>
320 <body>
321
322 <p>
323 Now that your kernel is configured, it is time to compile and install it. Exit
324 the configuration and start the compilation process:
325 </p>
326
327 <pre caption="Compiling the kernel">
328 # <i>make &amp;&amp; make modules_install</i>
329 </pre>
330
331 <p>
332 When the kernel has finished compiling, copy the kernel image to
333 <path>/boot</path>. Use whatever name you feel is appropriate for your kernel
334 choice and remember it as you will need it later on when you configure your
335 bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
336 name and version of your kernel.
337 </p>
338
339 <pre caption="Installing the kernel">
340 # <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
341 </pre>
342
343 <p>
344 Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
345 </p>
346
347 </body>
348 </subsection>
349 </section>
350 <section id="genkernel">
351 <title>Alternative: Using genkernel</title>
352 <body>
353
354 <p>
355 If you are reading this section, you have chosen to use our <c>genkernel</c>
356 script to configure your kernel for you.
357 </p>
358
359 <p>
360 Now that your kernel source tree is installed, it's now time to compile your
361 kernel by using our <c>genkernel</c> script to automatically build a kernel for
362 you. <c>genkernel</c> works by configuring a kernel nearly identically to the
363 way our Installation CD kernel is configured. This means that when you use
364 <c>genkernel</c> to build your kernel, your system will generally detect all
365 your hardware at boot-time, just like our Installation CD does. Because
366 genkernel doesn't require any manual kernel configuration, it is an ideal
367 solution for those users who may not be comfortable compiling their own kernels.
368 </p>
369
370 <p>
371 Now, let's see how to use genkernel. First, emerge the genkernel ebuild:
372 </p>
373
374 <pre caption="Emerging genkernel">
375 # <i>emerge genkernel</i>
376 </pre>
377
378 <p>
379 Now, compile your kernel sources by running <c>genkernel all</c>. Be aware
380 though, as <c>genkernel</c> compiles a kernel that supports almost all
381 hardware, this compilation will take quite a while to finish!
382 </p>
383
384 <p>
385 Note that, if your boot partition doesn't use ext2 or ext3 as filesystem you
386 might need to manually configure your kernel using <c>genkernel --menuconfig
387 all</c> and add support for your filesystem <e>in</e> the kernel (i.e.
388 <e>not</e> as a module). Users of LVM2 will probably want to add <c>--lvm2</c>
389 as an argument as well.
390 </p>
391
392 <pre caption="Running genkernel">
393 # <i>genkernel all</i>
394 </pre>
395
396 <p>
397 Once <c>genkernel</c> completes, a kernel, full set of modules and
398 <e>initial ram disk</e> (initramfs) will be created. We will use the kernel
399 and initrd when configuring a boot loader later in this document. Write
400 down the names of the kernel and initrd as you will need it when writing
401 the bootloader configuration file. The initrd will be started immediately after
402 booting to perform hardware autodetection (just like on the Installation CD)
403 before your "real" system starts up.
404 </p>
405
406 <pre caption="Checking the created kernel image name and initrd">
407 # <i>ls /boot/kernel* /boot/initramfs*</i>
408 </pre>
409
410 </body>
411 </section>
412 <section id="kernel_modules">
413 <title>Kernel Modules</title>
414
415 <subsection>
416 <include href="hb-install-kernelmodules.xml"/>
417 </subsection>
418
419 </section>
420 </sections>

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