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Thu Apr 12 15:53:31 2012 UTC (2 years, 3 months ago) by swift
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CONFIG_DEVTMPFS is also needed but not mentioned in handbook yet. Introducing for x86 and amd64... other arches should check if the requirement is for them valid as well and update accordingly

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 1.47 <!-- $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 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 1.47 <version>17</version>
17     <date>2012-04-12</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 swift 1.47 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 ---&gt;
211     Generic Driver Options ---&gt;
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 neysx 1.1 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 neysx 1.2 file system</c>.
221     </p>
222    
223 neysx 1.1 <pre caption="Selecting necessary file systems">
224     File systems ---&gt;
225     <comment>(Select one or more of the following options as needed by your system)</comment>
226 swift 1.39 &lt;*&gt; Second extended fs support
227     &lt;*&gt; Ext3 journalling file system support
228     &lt;*&gt; The Extended 4 (ext4) filesystem
229 neysx 1.1 &lt;*&gt; Reiserfs support
230     &lt;*&gt; JFS filesystem support
231     &lt;*&gt; XFS filesystem support
232 swift 1.39 ...
233     Pseudo Filesystems ---&gt;
234     [*] /proc file system support
235     [*] Virtual memory file system support (former shm fs)
236 swift 1.42
237 nightmorph 1.43 <comment>(Enable GPT partition label support if you used that previously)</comment>
238 swift 1.42 Partition Types ---&gt;
239     [*] Advanced partition selection
240     ...
241     [*] EFI GUID Partition support
242 neysx 1.1 </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 nightmorph 1.25 <pre caption="Selecting PPPoE necessary drivers">
250 neysx 1.2 Device Drivers ---&gt;
251 swift 1.46 Network device support ---&gt;
252 neysx 1.2 &lt;*&gt; PPP (point-to-point protocol) support
253     &lt;*&gt; PPP support for async serial ports
254     &lt;*&gt; PPP support for sync tty ports
255     </pre>
256    
257 neysx 1.1 <p>
258     The two compression options won't harm but are not definitely needed, neither
259 nightmorph 1.10 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 neysx 1.1 </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 neysx 1.2 <p test="func:keyval('arch')='x86'">
269 neysx 1.1 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 neysx 1.2 <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 neysx 1.1 <pre caption="Activating SMP support">
279     Processor type and features ---&gt;
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 nightmorph 1.24 <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 neysx 1.1 <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 neysx 1.2 Device Drivers ---&gt;
299 nightmorph 1.26 [*] HID Devices ---&gt;
300 neysx 1.2 &lt;*&gt; USB Human Interface Device (full HID) support
301 neysx 1.1 </pre>
302    
303 neysx 1.2 </body>
304     <body test="func:keyval('arch')='x86'">
305    
306 neysx 1.1 <p>
307 nightmorph 1.10 If you want PCMCIA support for your laptop, don't forget to enable
308 neysx 1.1 support for the PCMCIA card bridge present in your system:
309     </p>
310    
311 nightmorph 1.10 <pre caption="Enabling PCMCIA support">
312 swift 1.39 Bus options (PCI etc.) ---&gt;
313 neysx 1.1 PCCARD (PCMCIA/CardBus) support ---&gt;
314     &lt;*&gt; PCCard (PCMCIA/CardBus) support
315     <comment>(select 16 bit if you need support for older PCMCIA cards. Most people want this.)</comment>
316     &lt;*&gt; 16-bit PCMCIA support
317     [*] 32-bit CardBus support
318     <comment>(select the relevant bridges below)</comment>
319 swift 1.39 *** PC-card bridges ***
320 neysx 1.1 &lt;*&gt; CardBus yenta-compatible bridge support (NEW)
321     &lt;*&gt; Cirrus PD6729 compatible bridge support (NEW)
322     &lt;*&gt; i82092 compatible bridge support (NEW)
323     </pre>
324    
325     <p>
326 swift 1.38 When you've finished configuring the kernel, continue with <uri
327 neysx 1.1 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 swift 1.38 Now that your kernel is configured, it is time to compile and install it. Exit
338 neysx 1.1 the configuration and start the compilation process:
339     </p>
340    
341 nightmorph 1.10 <pre caption="Compiling the kernel">
342 neysx 1.2 # <i>make &amp;&amp; make modules_install</i>
343     </pre>
344    
345 neysx 1.1 <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 neysx 1.2 bootloader. Remember to replace <c><keyval id="kernel-name"/></c> with the
350     name and version of your kernel.
351 neysx 1.1 </p>
352    
353     <pre caption="Installing the kernel">
354 neysx 1.2 # <i>cp arch/<keyval id="arch-sub"/>/boot/bzImage /boot/<keyval id="kernel-name"/></i>
355 neysx 1.1 </pre>
356    
357 swift 1.46 </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 neysx 1.4 <p>
411     Now continue with <uri link="#kernel_modules">Kernel Modules</uri>.
412     </p>
413    
414 neysx 1.1 </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 swift 1.38 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 neysx 1.1 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 swift 1.38 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 swift 1.41 <e>not</e> as a module). Users of LVM2 will probably want to add <c>--lvm2</c>
456     as an argument as well.
457 neysx 1.1 </p>
458    
459     <pre caption="Running genkernel">
460     # <i>genkernel all</i>
461     </pre>
462    
463     <p>
464 swift 1.38 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 neysx 1.1 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 swift 1.38 the bootloader configuration file. The initrd will be started immediately after
469 neysx 1.1 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 nightmorph 1.22
482 neysx 1.1 <subsection>
483 nightmorph 1.22 <include href="hb-install-kernelmodules.xml"/>
484     </subsection>
485 neysx 1.1
486     </section>
487     </sections>

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