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Fix bug #408691 - Update instructions with initramfs information, bug #406961 - update kernel configuration entries

1 neysx 1.1 <?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 swift 1.46 <!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/handbook/hb-install-x86+amd64-kernel.xml,v 1.45 2012/02/22 21:27:45 swift Exp $ -->
8 neysx 1.1
9     <sections>
10    
11 neysx 1.6 <abstract>
12     The Linux kernel is the core of every distribution. This chapter
13     explains how to configure your kernel.
14     </abstract>
15    
16 swift 1.46 <version>16</version>
17     <date>2012-03-27</date>
18 neysx 1.1
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 neysx 1.11 located. Look for your timezone in <path>/usr/share/zoneinfo</path>, then copy
26     it to <path>/etc/localtime</path>. Please avoid the
27 neysx 1.1 <path>/usr/share/zoneinfo/Etc/GMT*</path> timezones as their names do not
28 neysx 1.11 indicate the expected zones. For instance, <path>GMT-8</path> is in fact
29     GMT+8.
30 neysx 1.1 </p>
31    
32     <pre caption="Setting the timezone information">
33     # <i>ls /usr/share/zoneinfo</i>
34 swift 1.45 <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" &gt; /etc/timezone</i>
38 neysx 1.1 </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 swift 1.38 Guide</uri>.
54 neysx 1.1 </p>
55    
56 nightmorph 1.22 <p>
57     For <keyval id="arch"/>-based systems we have <c>gentoo-sources</c>
58 neysx 1.18 (kernel source patched for extra features).
59 neysx 1.1 </p>
60    
61     <p>
62 nightmorph 1.8 Choose your kernel source and install it using <c>emerge</c>.
63 neysx 1.1 </p>
64    
65     <pre caption="Installing a kernel source">
66 nightmorph 1.8 # <i>emerge gentoo-sources</i>
67 neysx 1.1 </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 neysx 1.2 kernel source points to <c>gentoo-sources-<keyval id="kernel-version"/></c>.
73     Your version may be different, so keep this in mind.
74 neysx 1.1 </p>
75    
76     <pre caption="Viewing the kernel source symlink">
77     # <i>ls -l /usr/src/linux</i>
78 neysx 1.2 lrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -&gt; linux-<keyval id="kernel-version"/>
79 neysx 1.1 </pre>
80    
81     <p>
82 neysx 1.2 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 neysx 1.1 </p>
87    
88     <p>
89     If you want to manually configure your kernel, continue now with <uri
90 swift 1.38 link="#manual">Default: Manual Configuration</uri>. If you want to use
91     <c>genkernel</c> you should read <uri link="#genkernel">Alternative: Using
92 neysx 1.1 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 swift 1.38 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 neysx 1.1 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 neysx 1.2 </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 nightmorph 1.19 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 nightmorph 1.33 multilib system (mixed 32-bit/64-bit computing) by default, so this option is
161     required.
162 neysx 1.2 </p>
163    
164 nightmorph 1.33 <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&amp;chap=6#doc_chap2_sect2">instructions</uri> for
168 nightmorph 1.35 switching to a <uri link="/doc/en/gentoo-amd64-faq.xml">non-multilib
169 nightmorph 1.33 profile</uri>, as well as choosing the correct <uri
170     link="?part=1&amp;chap=10#doc_chap2_sect2">bootloader</uri>.
171     </note>
172    
173 neysx 1.2 <pre caption="Selecting processor type and features">
174     Processor type and features --->
175 swift 1.38 [ ] Machine Check / overheating reporting
176 nightmorph 1.27 [ ] Intel MCE Features
177     [ ] AMD MCE Features
178 neysx 1.2 Processor family (AMD-Opteron/Athlon64) --->
179 nightmorph 1.27 ( ) Opteron/Athlon64/Hammer/K8
180     ( ) Intel P4 / older Netburst based Xeon
181     ( ) Core 2/newer Xeon
182 nightmorph 1.32 ( ) Intel Atom
183 neysx 1.2 ( ) Generic-x86-64
184 nightmorph 1.19 Executable file formats / Emulations --->
185     [*] IA32 Emulation
186 neysx 1.2 </pre>
187    
188     </body>
189     <body test="func:keyval('arch')='x86'">
190    
191 neysx 1.1 <p>
192     Now select the correct processor family:
193     </p>
194    
195     <pre caption="Selecting correct processor family">
196     Processor type and features ---&gt;
197     <comment>(Change according to your system)</comment>
198     (<i>Athlon/Duron/K7</i>) Processor family
199     </pre>
200    
201 neysx 1.2 </body>
202     <body>
203    
204 neysx 1.1 <p>
205     Now go to <c>File Systems</c> and select support for the filesystems you use.
206     <e>Don't</e> compile them as modules, otherwise your Gentoo system will not be
207     able to mount your partitions. Also select <c>Virtual memory</c> and <c>/proc
208 neysx 1.2 file system</c>.
209     </p>
210    
211 neysx 1.1 <pre caption="Selecting necessary file systems">
212     File systems ---&gt;
213     <comment>(Select one or more of the following options as needed by your system)</comment>
214 swift 1.39 &lt;*&gt; Second extended fs support
215     &lt;*&gt; Ext3 journalling file system support
216     &lt;*&gt; The Extended 4 (ext4) filesystem
217 neysx 1.1 &lt;*&gt; Reiserfs support
218     &lt;*&gt; JFS filesystem support
219     &lt;*&gt; XFS filesystem support
220 swift 1.39 ...
221     Pseudo Filesystems ---&gt;
222     [*] /proc file system support
223     [*] Virtual memory file system support (former shm fs)
224 swift 1.42
225 nightmorph 1.43 <comment>(Enable GPT partition label support if you used that previously)</comment>
226 swift 1.42 Partition Types ---&gt;
227     [*] Advanced partition selection
228     ...
229     [*] EFI GUID Partition support
230 neysx 1.1 </pre>
231    
232     <p>
233     If you are using PPPoE to connect to the Internet or you are using a dial-up
234     modem, you will need the following options in the kernel:
235     </p>
236    
237 nightmorph 1.25 <pre caption="Selecting PPPoE necessary drivers">
238 neysx 1.2 Device Drivers ---&gt;
239 swift 1.46 Network device support ---&gt;
240 neysx 1.2 &lt;*&gt; PPP (point-to-point protocol) support
241     &lt;*&gt; PPP support for async serial ports
242     &lt;*&gt; PPP support for sync tty ports
243     </pre>
244    
245 neysx 1.1 <p>
246     The two compression options won't harm but are not definitely needed, neither
247 nightmorph 1.10 does the <c>PPP over Ethernet</c> option, that might only be used by <c>ppp</c>
248     when configured to do kernel mode PPPoE.
249 neysx 1.1 </p>
250    
251     <p>
252     If you require it, don't forget to include support in the kernel for your
253     ethernet card.
254     </p>
255    
256 neysx 1.2 <p test="func:keyval('arch')='x86'">
257 neysx 1.1 If you have an Intel CPU that supports HyperThreading (tm), or you have a
258     multi-CPU system, you should activate "Symmetric multi-processing support":
259     </p>
260    
261 neysx 1.2 <p test="func:keyval('arch')='AMD64'">
262     If you have a multi-CPU Opteron or a multi-core (e.g. AMD64 X2) system, you
263     should activate "Symmetric multi-processing support":
264     </p>
265    
266 neysx 1.1 <pre caption="Activating SMP support">
267     Processor type and features ---&gt;
268     [*] Symmetric multi-processing support
269     </pre>
270    
271     <note>
272     In multi-core systems, each core counts as one processor.
273     </note>
274    
275 nightmorph 1.24 <p test="func:keyval('arch')='x86'">
276     If you have more than 4GB of RAM, you need to enable "High Memory Support
277     (64G)".
278     </p>
279    
280 neysx 1.1 <p>
281     If you use USB Input Devices (like Keyboard or Mouse) don't forget to enable
282     those as well:
283     </p>
284    
285     <pre caption="Activating USB Support for Input Devices">
286 neysx 1.2 Device Drivers ---&gt;
287 nightmorph 1.26 [*] HID Devices ---&gt;
288 neysx 1.2 &lt;*&gt; USB Human Interface Device (full HID) support
289 neysx 1.1 </pre>
290    
291 neysx 1.2 </body>
292     <body test="func:keyval('arch')='x86'">
293    
294 neysx 1.1 <p>
295 nightmorph 1.10 If you want PCMCIA support for your laptop, don't forget to enable
296 neysx 1.1 support for the PCMCIA card bridge present in your system:
297     </p>
298    
299 nightmorph 1.10 <pre caption="Enabling PCMCIA support">
300 swift 1.39 Bus options (PCI etc.) ---&gt;
301 neysx 1.1 PCCARD (PCMCIA/CardBus) support ---&gt;
302     &lt;*&gt; PCCard (PCMCIA/CardBus) support
303     <comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
304     &lt;*&gt; 16-bit PCMCIA support
305     [*] 32-bit CardBus support
306     <comment>(select the relevant bridges below)</comment>
307 swift 1.39 *** PC-card bridges ***
308 neysx 1.1 &lt;*&gt; CardBus yenta-compatible bridge support (NEW)
309     &lt;*&gt; Cirrus PD6729 compatible bridge support (NEW)
310     &lt;*&gt; i82092 compatible bridge support (NEW)
311     </pre>
312    
313     <p>
314 swift 1.38 When you've finished configuring the kernel, continue with <uri
315 neysx 1.1 link="#compiling">Compiling and Installing</uri>.
316     </p>
317    
318     </body>
319     </subsection>
320     <subsection id="compiling">
321     <title>Compiling and Installing</title>
322     <body>
323    
324     <p>
325 swift 1.38 Now that your kernel is configured, it is time to compile and install it. Exit
326 neysx 1.1 the configuration and start the compilation process:
327     </p>
328    
329 nightmorph 1.10 <pre caption="Compiling the kernel">
330 neysx 1.2 # <i>make &amp;&amp; make modules_install</i>
331     </pre>
332    
333 neysx 1.1 <p>
334     When the kernel has finished compiling, copy the kernel image to
335     <path>/boot</path>. Use whatever name you feel is appropriate for your kernel
336     choice and remember it as you will need it later on when you configure your
337 neysx 1.2 bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
338     name and version of your kernel.
339 neysx 1.1 </p>
340    
341     <pre caption="Installing the kernel">
342 neysx 1.2 # <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
343 neysx 1.1 </pre>
344    
345 swift 1.46 </body>
346     </subsection>
347     <subsection id="initramfs">
348     <title>(Optional) Building an Initramfs</title>
349     <body>
350    
351     <p>
352     If you use a specific partition layout where important file system locations
353     (like <path>/usr</path> or <path>/var</path>) are on separate partitions, then
354     you will need to setup an initramfs so that this partition can be mounted before
355     it is needed.
356     </p>
357    
358     <p>
359     Without an initramfs, you risk that the system will not boot up properly as the
360     tools that are responsible for mounting the file systems need information that
361     resides on those file systems. An initramfs will pull in the necessary files
362     into an archive which is used right after the kernel boots, but before the
363     control is handed over to the <c>init</c> tool. Scripts on the initramfs will
364     then make sure that the partitions are properly mounted before the system
365     continues booting.
366     </p>
367    
368     <p>
369     To install an initramfs, install <c>genkernel</c> first, then have it
370     generate an initramfs for you.
371     </p>
372    
373     <pre caption="Building an initramfs">
374     # <i>emerge genkernel</i>
375     # <i>genkernel --install initramfs</i>
376     </pre>
377    
378     <p>
379     If you need specific support in the initramfs, such as lvm or raid, add in the
380     appropriate options to genkernel. See <c>genkernel --help</c> for more
381     information, or the next example which enables support for LVM and software raid
382     (mdadm):
383     </p>
384    
385     <pre caption="Building an initramfs with support for LVM and software raid">
386     # <i>genkernel --lvm --mdadm --install initramfs</i>
387     </pre>
388    
389     <p>
390     The initramfs will be stored in <path>/boot</path>. You can find the file by
391     simply listing the files starting with <path>initramfs</path>:
392     </p>
393    
394     <pre caption="Checking the initramfs file name">
395     # <i>ls /boot/initramfs*</i>
396     </pre>
397    
398 neysx 1.4 <p>
399     Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
400     </p>
401    
402 neysx 1.1 </body>
403     </subsection>
404     </section>
405     <section id="genkernel">
406     <title>Alternative: Using genkernel</title>
407     <body>
408    
409     <p>
410     If you are reading this section, you have chosen to use our <c>genkernel</c>
411     script to configure your kernel for you.
412     </p>
413    
414     <p>
415 swift 1.38 Now that your kernel source tree is installed, it's now time to compile your
416     kernel by using our <c>genkernel</c> script to automatically build a kernel for
417     you. <c>genkernel</c> works by configuring a kernel nearly identically to the
418     way our Installation CD kernel is configured. This means that when you use
419     <c>genkernel</c> to build your kernel, your system will generally detect all
420     your hardware at boot-time, just like our Installation CD does. Because
421     genkernel doesn't require any manual kernel configuration, it is an ideal
422 neysx 1.1 solution for those users who may not be comfortable compiling their own kernels.
423     </p>
424    
425     <p>
426     Now, let's see how to use genkernel. First, emerge the genkernel ebuild:
427     </p>
428    
429     <pre caption="Emerging genkernel">
430     # <i>emerge genkernel</i>
431     </pre>
432    
433     <p>
434     Now, compile your kernel sources by running <c>genkernel all</c>. Be aware
435     though, as <c>genkernel</c> compiles a kernel that supports almost all
436     hardware, this compilation will take quite a while to finish!
437     </p>
438    
439     <p>
440     Note that, if your boot partition doesn't use ext2 or ext3 as filesystem you
441 swift 1.38 might need to manually configure your kernel using <c>genkernel --menuconfig
442     all</c> and add support for your filesystem <e>in</e> the kernel (i.e.
443 swift 1.41 <e>not</e> as a module). Users of LVM2 will probably want to add <c>--lvm2</c>
444     as an argument as well.
445 neysx 1.1 </p>
446    
447     <pre caption="Running genkernel">
448     # <i>genkernel all</i>
449     </pre>
450    
451     <p>
452 swift 1.38 Once <c>genkernel</c> completes, a kernel, full set of modules and
453     <e>initial ram disk</e> (initramfs) will be created. We will use the kernel
454 neysx 1.1 and initrd when configuring a boot loader later in this document. Write
455     down the names of the kernel and initrd as you will need it when writing
456 swift 1.38 the bootloader configuration file. The initrd will be started immediately after
457 neysx 1.1 booting to perform hardware autodetection (just like on the Installation CD)
458     before your "real" system starts up.
459     </p>
460    
461     <pre caption="Checking the created kernel image name and initrd">
462     # <i>ls /boot/kernel* /boot/initramfs*</i>
463     </pre>
464    
465     </body>
466     </section>
467     <section id="kernel_modules">
468     <title>Kernel Modules</title>
469 nightmorph 1.22
470 neysx 1.1 <subsection>
471 nightmorph 1.22 <include href="hb-install-kernelmodules.xml"/>
472     </subsection>
473 neysx 1.1
474     </section>
475     </sections>

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