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Revision 1.39 - (show annotations) (download) (as text)
Mon Aug 22 17:28:40 2011 UTC (3 years, 4 months ago) by swift
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Fix bug #372077 - Update kernel configuration for x86/x86_64 architectures. Thanks to nimiux for the patch

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 1.38 2011/08/22 17:23:47 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>10</version>
17 <date>2011-08-22</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 Pseudo Filesystems ---&gt;
212 [*] /proc file system support
213 [*] Virtual memory file system support (former shm fs)
214
215 <comment>(Select one or more of the following options as needed by your system)</comment>
216 &lt;*&gt; Second extended fs support
217 &lt;*&gt; Ext3 journalling file system support
218 &lt;*&gt; The Extended 4 (ext4) filesystem
219 &lt;*&gt; Reiserfs support
220 &lt;*&gt; JFS filesystem support
221 &lt;*&gt; XFS filesystem support
222 ...
223 Pseudo Filesystems ---&gt;
224 [*] /proc file system support
225 [*] Virtual memory file system support (former shm fs)
226 </pre>
227
228 <p>
229 If you are using PPPoE to connect to the Internet or you are using a dial-up
230 modem, you will need the following options in the kernel:
231 </p>
232
233 <pre caption="Selecting PPPoE necessary drivers">
234 Device Drivers ---&gt;
235 Networking device Support ---&gt;
236 &lt;*&gt; PPP (point-to-point protocol) support
237 &lt;*&gt; PPP support for async serial ports
238 &lt;*&gt; PPP support for sync tty ports
239 </pre>
240
241 <p>
242 The two compression options won't harm but are not definitely needed, neither
243 does the <c>PPP over Ethernet</c> option, that might only be used by <c>ppp</c>
244 when configured to do kernel mode PPPoE.
245 </p>
246
247 <p>
248 If you require it, don't forget to include support in the kernel for your
249 ethernet card.
250 </p>
251
252 <p test="func:keyval('arch')='x86'">
253 If you have an Intel CPU that supports HyperThreading (tm), or you have a
254 multi-CPU system, you should activate "Symmetric multi-processing support":
255 </p>
256
257 <p test="func:keyval('arch')='AMD64'">
258 If you have a multi-CPU Opteron or a multi-core (e.g. AMD64 X2) system, you
259 should activate "Symmetric multi-processing support":
260 </p>
261
262 <pre caption="Activating SMP support">
263 Processor type and features ---&gt;
264 [*] Symmetric multi-processing support
265 </pre>
266
267 <note>
268 In multi-core systems, each core counts as one processor.
269 </note>
270
271 <p test="func:keyval('arch')='x86'">
272 If you have more than 4GB of RAM, you need to enable "High Memory Support
273 (64G)".
274 </p>
275
276 <p>
277 If you use USB Input Devices (like Keyboard or Mouse) don't forget to enable
278 those as well:
279 </p>
280
281 <pre caption="Activating USB Support for Input Devices">
282 Device Drivers ---&gt;
283 [*] HID Devices ---&gt;
284 &lt;*&gt; USB Human Interface Device (full HID) support
285 </pre>
286
287 </body>
288 <body test="func:keyval('arch')='x86'">
289
290 <p>
291 If you want PCMCIA support for your laptop, don't forget to enable
292 support for the PCMCIA card bridge present in your system:
293 </p>
294
295 <pre caption="Enabling PCMCIA support">
296 Bus options (PCI etc.) ---&gt;
297 PCCARD (PCMCIA/CardBus) support ---&gt;
298 &lt;*&gt; PCCard (PCMCIA/CardBus) support
299 <comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
300 &lt;*&gt; 16-bit PCMCIA support
301 [*] 32-bit CardBus support
302 <comment>(select the relevant bridges below)</comment>
303 *** PC-card bridges ***
304 &lt;*&gt; CardBus yenta-compatible bridge support (NEW)
305 &lt;*&gt; Cirrus PD6729 compatible bridge support (NEW)
306 &lt;*&gt; i82092 compatible bridge support (NEW)
307 </pre>
308
309 <p>
310 When you've finished configuring the kernel, continue with <uri
311 link="#compiling">Compiling and Installing</uri>.
312 </p>
313
314 </body>
315 </subsection>
316 <subsection id="compiling">
317 <title>Compiling and Installing</title>
318 <body>
319
320 <p>
321 Now that your kernel is configured, it is time to compile and install it. Exit
322 the configuration and start the compilation process:
323 </p>
324
325 <pre caption="Compiling the kernel">
326 # <i>make &amp;&amp; make modules_install</i>
327 </pre>
328
329 <p>
330 When the kernel has finished compiling, copy the kernel image to
331 <path>/boot</path>. Use whatever name you feel is appropriate for your kernel
332 choice and remember it as you will need it later on when you configure your
333 bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
334 name and version of your kernel.
335 </p>
336
337 <pre caption="Installing the kernel">
338 # <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
339 </pre>
340
341 <p>
342 Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
343 </p>
344
345 </body>
346 </subsection>
347 </section>
348 <section id="genkernel">
349 <title>Alternative: Using genkernel</title>
350 <body>
351
352 <p>
353 If you are reading this section, you have chosen to use our <c>genkernel</c>
354 script to configure your kernel for you.
355 </p>
356
357 <p>
358 Now that your kernel source tree is installed, it's now time to compile your
359 kernel by using our <c>genkernel</c> script to automatically build a kernel for
360 you. <c>genkernel</c> works by configuring a kernel nearly identically to the
361 way our Installation CD kernel is configured. This means that when you use
362 <c>genkernel</c> to build your kernel, your system will generally detect all
363 your hardware at boot-time, just like our Installation CD does. Because
364 genkernel doesn't require any manual kernel configuration, it is an ideal
365 solution for those users who may not be comfortable compiling their own kernels.
366 </p>
367
368 <p>
369 Now, let's see how to use genkernel. First, emerge the genkernel ebuild:
370 </p>
371
372 <pre caption="Emerging genkernel">
373 # <i>emerge genkernel</i>
374 </pre>
375
376 <p>
377 Next, copy over the kernel configuration used by the Installation CD to the
378 location where genkernel looks for the default kernel configuration:
379 </p>
380
381 <pre test="func:keyval('arch')='x86'" caption="Copying over the Installation CD kernel config">
382 # <i>zcat /proc/config.gz &gt; /usr/share/genkernel/arch/x86/kernel-config</i>
383 </pre>
384
385 <pre test="func:keyval('arch')='AMD64'" caption="Copying over the Installation CD kernel config">
386 # <i>zcat /proc/config.gz &gt; /usr/share/genkernel/arch/x86_64/kernel-config</i>
387 </pre>
388
389 <p>
390 Now, compile your kernel sources by running <c>genkernel all</c>. Be aware
391 though, as <c>genkernel</c> compiles a kernel that supports almost all
392 hardware, this compilation will take quite a while to finish!
393 </p>
394
395 <p>
396 Note that, if your boot partition doesn't use ext2 or ext3 as filesystem you
397 might need to manually configure your kernel using <c>genkernel --menuconfig
398 all</c> and add support for your filesystem <e>in</e> the kernel (i.e.
399 <e>not</e> as a module). Users of EVMS2 or LVM2 will probably want to add
400 <c>--evms2</c> or <c>--lvm2</c> as arguments as well.
401 </p>
402
403 <pre caption="Running genkernel">
404 # <i>genkernel all</i>
405 </pre>
406
407 <p>
408 Once <c>genkernel</c> completes, a kernel, full set of modules and
409 <e>initial ram disk</e> (initramfs) will be created. We will use the kernel
410 and initrd when configuring a boot loader later in this document. Write
411 down the names of the kernel and initrd as you will need it when writing
412 the bootloader configuration file. The initrd will be started immediately after
413 booting to perform hardware autodetection (just like on the Installation CD)
414 before your "real" system starts up.
415 </p>
416
417 <pre caption="Checking the created kernel image name and initrd">
418 # <i>ls /boot/kernel* /boot/initramfs*</i>
419 </pre>
420
421 </body>
422 </section>
423 <section id="kernel_modules">
424 <title>Kernel Modules</title>
425
426 <subsection>
427 <include href="hb-install-kernelmodules.xml"/>
428 </subsection>
429
430 </section>
431 </sections>

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