dd59ed300d
describing the versions of FreeBSD that support PAE. Submitted by: hmp Reviewed by: simon Discussed with: simon, murray
1650 lines
71 KiB
Text
1650 lines
71 KiB
Text
<!--
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The FreeBSD Documentation Project
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$FreeBSD$
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-->
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<chapter id="kernelconfig">
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<chapterinfo>
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<authorgroup>
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<author>
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<firstname>Jim</firstname>
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<surname>Mock</surname>
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<contrib>Updated and restructured by </contrib>
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<!-- Mar 2000 -->
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</author>
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</authorgroup>
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<authorgroup>
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<author>
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<firstname>Jake</firstname>
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<surname>Hamby</surname>
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<contrib>Originally contributed by </contrib>
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<!-- 6 Oct 1995 -->
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</author>
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</authorgroup>
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</chapterinfo>
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<title>Configuring the FreeBSD Kernel</title>
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<sect1 id="kernelconfig-synopsis">
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<title>Synopsis</title>
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<indexterm>
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<primary>kernel</primary>
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<secondary>building a custom kernel</secondary>
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</indexterm>
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<para>The kernel is the core of the &os; operating system. It is
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responsible for managing memory, enforcing security controls,
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networking, disk access, and much more. While more and more of &os;
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becomes dynamically configurable it is still occasionally necessary to
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reconfigure and recompile your kernel.</para>
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<para>After reading this chapter, you will know:</para>
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<itemizedlist>
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<listitem>
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<para>Why you might need to build a custom kernel.</para>
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</listitem>
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<listitem>
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<para>How to write a kernel configuration file, or alter an existing
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configuration file.</para>
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</listitem>
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<listitem>
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<para>How to use the kernel configuration file to create and build a
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new kernel.</para>
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</listitem>
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<listitem>
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<para>How to install the new kernel.</para>
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</listitem>
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<listitem>
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<para>How to create any entries in <filename>/dev</filename> that may
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be required.</para>
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</listitem>
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<listitem>
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<para>How to troubleshoot if things go wrong.</para>
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</listitem>
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</itemizedlist>
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</sect1>
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<sect1 id="kernelconfig-custom-kernel">
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<title>Why Build a Custom Kernel?</title>
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<para>Traditionally, &os; has had what is called a
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<quote>monolithic</quote> kernel. This means that the kernel was one
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large program, supported a fixed list of devices, and if you wanted to
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change the kernel's behavior then you had to compile a new kernel, and
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then reboot your computer with the new kernel.</para>
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<para>Today, &os; is rapidly moving to a model where much of the
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kernel's functionality is contained in modules which can be
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dynamically loaded and unloaded from the kernel as necessary.
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This allows the kernel to adapt to new hardware suddenly
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becoming available (such as PCMCIA cards in a laptop), or for
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new functionality to be brought into the kernel that was not
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necessary when the kernel was originally compiled. This is
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known as a modular kernel. Colloquially these are called
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KLDs.</para>
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<para>Despite this, it is still necessary to carry out some static kernel
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configuration. In some cases this is because the functionality is so
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tied to the kernel that it can not be made dynamically loadable. In
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others it may simply be because no one has yet taken the time to write a
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dynamic loadable kernel module for that functionality yet.</para>
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<para>Building a custom kernel is one of the most important rites of
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passage nearly every &unix; user must endure. This process, while
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time consuming, will provide many benefits to your &os; system.
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Unlike the <filename>GENERIC</filename> kernel, which must support a
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wide range of hardware, a custom kernel only contains support for
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<emphasis>your</emphasis> PC's hardware. This has a number of
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benefits, such as:</para>
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<itemizedlist>
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<listitem>
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<para>Faster boot time. Since the kernel will only probe the
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hardware you have on your system, the time it takes your system to
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boot will decrease dramatically.</para>
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</listitem>
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<listitem>
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<para>Less memory usage. A custom kernel often uses less memory
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than the <filename>GENERIC</filename> kernel, which is important
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because the kernel must always be present in real
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memory. For this reason, a custom kernel is especially useful
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on a system with a small amount of RAM.</para>
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</listitem>
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<listitem>
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<para>Additional hardware support. A custom kernel allows you to
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add in support for devices such as sound cards, which are not
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present in the <filename>GENERIC</filename> kernel.</para>
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</listitem>
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</itemizedlist>
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</sect1>
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<sect1 id="kernelconfig-building">
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<title>Building and Installing a Custom Kernel</title>
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<indexterm>
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<primary>kernel</primary>
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<secondary>building / installing</secondary>
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</indexterm>
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<para>First, let us take a quick tour of the kernel build directory.
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All directories mentioned will be relative to the main
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<filename>/usr/src/sys</filename> directory, which is also
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accessible through <filename>/sys</filename>. There are a number of
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subdirectories here representing different parts of the kernel, but
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the most important, for our purposes, are
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<filename><replaceable>arch</replaceable>/conf</filename>, where you
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will edit your custom kernel configuration, and
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<filename>compile</filename>, which is the staging area where your
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kernel will be built. <replaceable>arch</replaceable> represents
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either <filename>i386</filename>, <filename>alpha</filename>, or
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<filename>pc98</filename> (an alternative development branch of PC
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hardware, popular in Japan). Everything inside a particular
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architecture's directory deals with that architecture only; the rest
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of the code is common to all platforms to which &os; could
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potentially be ported. Notice the logical organization of the
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directory structure, with each supported device, file system, and
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option in its own subdirectory. &os; 5.X and up has support for
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<filename>sparc64</filename>, and a few other architectures under
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development.</para>
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<note>
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<para>If there is <emphasis>not</emphasis> a
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<filename>/usr/src/sys</filename> directory on your system,
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then the kernel source has not been installed. The easiest
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way to do this is by running
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<command>/stand/sysinstall</command> as
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<username>root</username>, choosing
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<guimenuitem>Configure</guimenuitem>, then
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<guimenuitem>Distributions</guimenuitem>, then
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<guimenuitem>src</guimenuitem>, then
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<guimenuitem>sys</guimenuitem>. If you have an aversion to
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<application>sysinstall</application> and you have access to
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an <quote>official</quote> &os; CDROM, then you can also
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install the source from the command line:</para>
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<screen>&prompt.root; <userinput>mount /cdrom</userinput>
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&prompt.root; <userinput>mkdir -p /usr/src/sys</userinput>
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&prompt.root; <userinput>ln -s /usr/src/sys /sys</userinput>
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&prompt.root; <userinput>cat /cdrom/src/ssys.[a-d]* | tar -xzvf -</userinput></screen>
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</note>
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<para>Next, move to the
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<filename><replaceable>arch</replaceable>/conf</filename> directory
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and copy the <filename>GENERIC</filename> configuration file to the
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name you want to give your kernel. For example:</para>
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<screen>&prompt.root; <userinput>cd /usr/src/sys/i386/conf</userinput>
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&prompt.root; <userinput>cp GENERIC MYKERNEL</userinput></screen>
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<para>Traditionally, this name is in all capital letters and, if you
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are maintaining multiple &os; machines with different hardware,
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it is a good idea to name it after your machine's hostname. We will
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call it <filename>MYKERNEL</filename> for the purpose of this
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example.</para>
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<tip>
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<para>Storing your kernel config file directly under
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<filename>/usr/src</filename> can be a bad idea. If you are
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experiencing problems it can be tempting to just delete
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<filename>/usr/src</filename> and start again. Five seconds after
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you do that you realize that you have deleted your custom kernel
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config file. Do not edit <filename>GENERIC</filename>
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directly, as it may get overwritten the next time you
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<link linkend="cutting-edge">update your source tree</link>, and
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your kernel modifications will be lost.</para>
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<para>You might want to keep your kernel config file elsewhere, and then
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create a symbolic link to the file in the <filename>i386</filename>
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directory.</para>
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<para>For example:</para>
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<screen>&prompt.root; <userinput>cd /usr/src/sys/i386/conf</userinput>
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&prompt.root; <userinput>mkdir /root/kernels</userinput>
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&prompt.root; <userinput>cp GENERIC /root/kernels/<replaceable>MYKERNEL</replaceable></userinput>
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&prompt.root; <userinput>ln -s /root/kernels/<replaceable>MYKERNEL</replaceable></userinput></screen>
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</tip>
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<note>
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<para>You must execute these and all of the following commands under
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the <username>root</username> account or you will get
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<errortype>permission denied</errortype> errors.</para>
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</note>
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<para>Now, edit <filename>MYKERNEL</filename> with your favorite text
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editor. If you are just starting out, the only editor available
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will probably be <application>vi</application>, which is too complex to
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explain here, but is covered well in many books in the <link
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linkend="bibliography">bibliography</link>. However, &os; does
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offer an easier editor called <application>ee</application> which, if
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you are a beginner, should be your editor of choice. Feel free to
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change the comment lines at the top to reflect your configuration or
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the changes you have made to differentiate it from
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<filename>GENERIC</filename>.</para>
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<indexterm><primary>SunOS</primary></indexterm>
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<para>If you have built a kernel under &sunos; or some other BSD
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operating system, much of this file will be very familiar to you.
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If you are coming from some other operating system such as DOS, on
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the other hand, the <filename>GENERIC</filename> configuration file
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might seem overwhelming to you, so follow the descriptions in the
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<link linkend="kernelconfig-config">Configuration File</link>
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section slowly and carefully.</para>
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<note>
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<para>Be sure to always check the file
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<filename>/usr/src/UPDATING</filename>, before you perform any update
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steps, in the case you <link
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linkend="cutting-edge">sync your source tree</link> with the
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latest sources of the &os; project.
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In this file all important issues with updating &os;
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are typed out. <filename>/usr/src/UPDATING</filename> always fits
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your version of the &os; source, and is therefore more accurate
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for new information than the handbook.</para>
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</note>
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<para>You must now compile the source code for the kernel. There are two
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procedures you can use to do this, and the one you will use depends on
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why you are rebuilding the kernel, and the version of &os; you are
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running.</para>
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<itemizedlist>
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<listitem>
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<para>If you have installed <emphasis>only</emphasis> the kernel
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source code, use procedure 1.</para>
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</listitem>
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<listitem>
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<para>If you are running a &os; version prior to 4.0, and you are
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<emphasis>not</emphasis> upgrading to &os; 4.0 or higher using
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the <maketarget>make world</maketarget> procedure, use procedure 1.
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</para>
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</listitem>
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<listitem>
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<para>If you are building a new kernel without updating the source
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code (perhaps just to add a new option, such as
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<literal>IPFIREWALL</literal>) you can use either procedure.</para>
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</listitem>
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<listitem>
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<para>If you are rebuilding the kernel as part of a
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<maketarget>make world</maketarget> process, use procedure 2.
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</para>
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</listitem>
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</itemizedlist>
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<procedure>
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<title>Procedure 1. Building a Kernel the <quote>Traditional</quote> Way</title>
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<step>
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<para>Run &man.config.8; to generate the kernel source code.</para>
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<screen>&prompt.root; <userinput>/usr/sbin/config <replaceable>MYKERNEL</replaceable></userinput></screen>
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</step>
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<step>
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<para>Change into the build directory. This is printed out after running the aforementioned
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command.</para>
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<screen>&prompt.root; <userinput>cd ../compile/<replaceable>MYKERNEL</replaceable></userinput></screen>
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<para>For &os; version prior to 5.0, use instead:</para>
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<screen>&prompt.root; <userinput>cd ../../compile/<replaceable>MYKERNEL</replaceable></userinput></screen>
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</step>
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<step>
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<para>Compile the kernel.</para>
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<screen>&prompt.root; <userinput>make depend</userinput>
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&prompt.root; <userinput>make</userinput></screen>
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</step>
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<step>
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<para>Install the new kernel.</para>
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<screen>&prompt.root; <userinput>make install</userinput></screen>
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</step>
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</procedure>
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<procedure>
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<title>Procedure 2. Building a Kernel the <quote>New</quote>
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Way</title>
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<step>
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<para>Change to the <filename>/usr/src</filename> directory.</para>
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<screen>&prompt.root; <userinput>cd /usr/src</userinput></screen>
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</step>
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<step>
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<para>Compile the kernel.</para>
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<screen>&prompt.root; <userinput>make buildkernel KERNCONF=<replaceable>MYKERNEL</replaceable></userinput></screen>
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</step>
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<step>
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<para>Install the new kernel.</para>
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<screen>&prompt.root; <userinput>make installkernel KERNCONF=<replaceable>MYKERNEL</replaceable></userinput></screen>
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</step>
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</procedure>
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<note>
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<para>In &os; 4.2 and older you must replace
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<literal>KERNCONF=</literal> with <literal>KERNEL=</literal>.
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4.2-STABLE that was fetched before Feb 2nd, 2001 does not
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recognize <literal>KERNCONF=</literal>.</para>
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</note>
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<indexterm>
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<primary><command>cvsup</command></primary>
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</indexterm>
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<indexterm><primary>anonymous CVS</primary></indexterm>
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<indexterm><primary>CTM</primary></indexterm>
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<indexterm>
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<primary>CVS</primary>
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<secondary>anonymous</secondary>
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</indexterm>
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<para>If you have <emphasis>not</emphasis> upgraded your source
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tree in any way (you have not run <application>CVSup</application>,
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<application>CTM</application>, or used
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<application>anoncvs</application>), then you should use the
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<command>config</command>, <maketarget>make depend</maketarget>,
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<command>make</command>, <maketarget>make install</maketarget> sequence.
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</para>
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<indexterm>
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<primary><filename>kernel.old</filename></primary>
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</indexterm>
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<para>The new kernel will be copied to the root directory as
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<filename>/kernel</filename> and the old kernel will be moved to
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<filename>/kernel.old</filename>. Now, shutdown the system and
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reboot to use your new kernel. In case something goes wrong, there are
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some <link linkend="kernelconfig-trouble">troubleshooting</link>
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instructions at the end of this chapter. Be sure to read the
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section which explains how to recover in case your new kernel <link
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linkend="kernelconfig-noboot">does not boot</link>.</para>
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<note>
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<para>As of &os; 5.0, kernels are installed along with their
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modules in <filename>/boot/kernel</filename>, and old kernels
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will be backed up in <filename>/boot/kernel.old</filename>.
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Other files relating to the boot process, such as the boot
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&man.loader.8; and configuration are also stored in
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<filename>/boot</filename>. Third party or custom modules
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may be placed in <filename>/boot/modules</filename>, although
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users should be aware that keeping modules in sync with the
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compiled kernel is very important. Modules not intended
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to run with the compiled kernel may result in instability
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or incorrectness.</para>
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</note>
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<note>
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<para>If you have added any new devices (such as sound cards)
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and you are running &os; 4.X or previous versions, you
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may have to add some device nodes to your
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<filename>/dev</filename> directory before you can use
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them. For more information, take a look at <link
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linkend="kernelconfig-nodes">Making Device Nodes</link>
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section later on in this chapter.</para>
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</note>
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</sect1>
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<sect1 id="kernelconfig-config">
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<title>The Configuration File</title>
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<indexterm>
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<primary>kernel</primary>
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<secondary>LINT</secondary>
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</indexterm>
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<indexterm><primary>LINT</primary></indexterm>
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<indexterm>
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<primary>kernel</primary>
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<secondary>config file</secondary>
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</indexterm>
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<para>The general format of a configuration file is quite simple.
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Each line contains a keyword and one or more arguments. For
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simplicity, most lines only contain one argument. Anything
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following a <literal>#</literal> is considered a comment and
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ignored. The following sections describe each keyword, generally in
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the order they are listed in <filename>GENERIC</filename>, although
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some related keywords have been grouped together in a single section
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(such as Networking) even though they are actually scattered
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throughout the <filename>GENERIC</filename> file. <anchor
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id="kernelconfig-options"> An exhaustive list of options and more
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detailed explanations of the device lines is present in the
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<filename>LINT</filename> configuration file, located in the same
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directory as <filename>GENERIC</filename>. If you are in doubt as
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to the purpose or necessity of a line, check first in
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<filename>LINT</filename>.</para>
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<note><para>In &os; 5.X and above the <filename>LINT</filename> is
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non-existent. See the <filename>NOTES</filename> file for
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architecture dependent options. Some options, mainly
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architecture independent ones, are stored in the
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<filename>/usr/src/sys/conf/NOTES</filename> file. It's
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advisable to review the options in here also.</para></note>
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<indexterm>
|
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<primary>kernel</primary>
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<secondary>example config file</secondary>
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</indexterm>
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<para>The following is an example <filename>GENERIC</filename> kernel
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configuration file with various additional comments where needed for
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clarity. This example should match your copy in
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<filename>/usr/src/sys/i386/conf/GENERIC</filename> fairly
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closely. For details of all the possible kernel options, see
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<filename>/usr/src/sys/i386/conf/LINT</filename>.</para>
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<programlisting>#
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# GENERIC -- Generic kernel configuration file for &os;/i386
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#
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# For more information on this file, please read the handbook section on
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# Kernel Configuration Files:
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#
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# http://www.&os;.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html
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#
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# The handbook is also available locally in /usr/share/doc/handbook
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# if you've installed the doc distribution, otherwise always see the
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# &os; World Wide Web server (http://www.FreeBSD.org/) for the
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# latest information.
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#
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# An exhaustive list of options and more detailed explanations of the
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# device lines is also present in the ../../conf/NOTES and NOTES files.
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# If you are in doubt as to the purpose or necessity of a line, check first
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# in NOTES.
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#
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# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.380 2003/03/29 13:36:41 mdodd Exp $</programlisting>
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|
|
<para>The following are the mandatory keywords required in
|
|
<emphasis>every</emphasis> kernel you build:</para>
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>machine</secondary>
|
|
</indexterm>
|
|
|
|
<programlisting>machine i386</programlisting>
|
|
|
|
<para>This is the machine architecture. It must be either
|
|
<literal>i386</literal>, <literal>pc98</literal>,
|
|
<literal>sparc64</literal>, <literal>alpha</literal>,
|
|
<literal>ia64</literal>, <literal>amd64</literal>, or
|
|
<literal>powerpc</literal>.</para>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>cpu</secondary>
|
|
</indexterm>
|
|
<programlisting>cpu I486_CPU
|
|
cpu I586_CPU
|
|
cpu I686_CPU</programlisting>
|
|
|
|
<para>The above option specifies the type of CPU you have in your
|
|
system. You may have multiple instances of the CPU line (i.e.,
|
|
you are not sure whether you should use
|
|
<literal>I586_CPU</literal> or <literal>I686_CPU</literal>),
|
|
however, for a custom kernel, it is best to specify only the CPU
|
|
you have. If you are unsure of your CPU type, you can check the
|
|
<filename>/var/run/dmesg.boot</filename> file to view your boot
|
|
up messages.</para>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>cpu type</secondary>
|
|
</indexterm>
|
|
<para>Support for <literal>I386_CPU</literal> is still provided in the
|
|
source of &os;, but it is disabled by default in both -STABLE and
|
|
-CURRENT. This means that to install &os; with a 386-class cpu, you now
|
|
have the following options:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>Install an older &os; release and rebuild from source as
|
|
described in <xref linkend="kernelconfig-building">.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Build the userland and kernel on a newer machine and install on
|
|
the 386 using the precompiled <filename>/usr/obj</filename>
|
|
files (see <xref linkend="small-lan"> for details).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Roll your own release of FreeBSD which includes
|
|
<literal>I386_CPU</literal> support in the kernels of the
|
|
installation CD-ROM.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The first of these options is probably the easiest of all, but you
|
|
will need a lot of disk space on a 386-class machine which may be
|
|
difficult to find.</para>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>ident</secondary>
|
|
</indexterm>
|
|
|
|
<programlisting>ident GENERIC</programlisting>
|
|
|
|
<para>This is the identification of the kernel. You should change
|
|
this to whatever you named your kernel,
|
|
i.e. <literal>MYKERNEL</literal> if you have followed the
|
|
instructions of the previous examples. The value you put in the
|
|
<literal>ident</literal> string will print when you boot up the
|
|
kernel, so it is useful to give the new kernel a different name if you
|
|
want to keep it separate from your usual kernel (i.e. you want to
|
|
build an experimental kernel).</para>
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>maxusers</secondary>
|
|
</indexterm>
|
|
|
|
<programlisting>maxusers <replaceable>n</replaceable></programlisting>
|
|
|
|
<para>The <literal>maxusers</literal> option sets the size of a number
|
|
of important system tables. This number is supposed to be roughly
|
|
equal to the number of simultaneous users you expect to have on your
|
|
machine.</para>
|
|
|
|
<para>Starting with &os; 4.5, the system will auto-tune this setting
|
|
for you if you explicitly set it to <literal>0</literal><footnote>
|
|
<para>The auto-tuning algorithm sets <literal>maxuser</literal> equal
|
|
to the amount of memory in the system, with a minimum of 32, and a
|
|
maximum of 384.</para></footnote>.
|
|
In &os; 5.X, <literal>maxusers</literal> will default to
|
|
<literal>0</literal> if not specified. If you are using an
|
|
version of &os; earlier than 4.5, or you want to manage it
|
|
yourself you will want to set
|
|
<literal>maxusers</literal> to at least 4, especially if you are
|
|
using the X Window System or compiling software. The reason is that
|
|
the most important table set by <literal>maxusers</literal> is the
|
|
maximum number of processes, which is set to <literal>20 + 16 *
|
|
maxusers</literal>, so if you set <literal>maxusers</literal> to 1,
|
|
then you can only have 36 simultaneous processes, including the 18
|
|
or so that the system starts up at boot time, and the 15 or so you
|
|
will probably create when you start the X Window System. Even a
|
|
simple task like reading a manual page will start up nine processes to
|
|
filter, decompress, and view it. Setting
|
|
<literal>maxusers</literal> to 64 will allow you to have up to 1044
|
|
simultaneous processes, which should be enough for nearly all uses.
|
|
If, however, you see the dreaded <errortype>proc table
|
|
full</errortype> error when trying to start another program, or are
|
|
running a server with a large number of simultaneous users (like
|
|
<hostid role="fqdn">ftp.FreeBSD.org</hostid>), you can always
|
|
increase the number and rebuild.</para>
|
|
|
|
<note>
|
|
<para><literal>maxusers</literal> does <emphasis>not</emphasis>
|
|
limit the number of users which can log into your machine. It
|
|
simply sets various table sizes to reasonable values considering
|
|
the maximum number of users you will likely have on your system
|
|
and how many processes each of them will be running. One keyword
|
|
which <emphasis>does</emphasis> limit the number of simultaneous
|
|
<emphasis>remote logins and X terminal windows</emphasis> is <link
|
|
linkend="kernelconfig-ptys"><literal>pseudo-device pty
|
|
16</literal></link>.</para>
|
|
</note>
|
|
|
|
<programlisting># Floating point support - do not disable.
|
|
device npx0 at nexus? port IO_NPX irq 13</programlisting>
|
|
|
|
<para><literal>npx0</literal> is the interface to the floating point
|
|
math unit in &os;, which is either the hardware co-processor or
|
|
the software math emulator. This is <emphasis>not</emphasis>
|
|
optional.</para>
|
|
|
|
<programlisting># Pseudo devices - the number indicates how many units to allocate.
|
|
pseudo-device loop # Network loopback</programlisting>
|
|
|
|
<para>This is the generic loopback device for TCP/IP. If you telnet
|
|
or FTP to <hostid>localhost</hostid> (a.k.a., <hostid
|
|
role="ipaddr">127.0.0.1</hostid>) it will come back at you through
|
|
this pseudo-device. This is <emphasis>mandatory</emphasis>.</para>
|
|
|
|
<para>Everything that follows is more or less optional. See the notes
|
|
underneath or next to each option for more information.</para>
|
|
|
|
<programlisting>#To statically compile in device wiring instead of /boot/device.hints
|
|
#hints "GENERIC.hints" #Default places to look for devices.</programlisting>
|
|
|
|
<para>In &os; 5.X and newer versions the &man.device.hints.5; is
|
|
used to configure options of the device drivers. The default
|
|
location that &man.loader.8; will check at boot time is
|
|
<filename>/boot/device.hints</filename>. Using the
|
|
<literal>hints</literal> option you can compile these hints
|
|
statically into your kernel. Then there is no need to create a
|
|
<filename>device.hints</filename> file in
|
|
<filename>/boot</filename>.</para>
|
|
|
|
<!-- XXX: Add a comment here that explains when compiling hints into the kernel is a good idea and why. -->
|
|
|
|
<programlisting>#makeoptions DEBUG=-g #Build kernel with gdb(1) debug symbols</programlisting>
|
|
|
|
<para>The normal build process of the &os; does not include
|
|
debugging information when building the kernel and strips most
|
|
symbols after the resulting kernel is linked, to save some space
|
|
at the install location. If you are going to do tests of kernels
|
|
in the -CURRENT branch or develop changes of your own for the &os;
|
|
kernel, you might want to uncomment this line. It will enable the
|
|
use of the <option>-g</option> option which enables debugging
|
|
information when passed to &man.gcc.1;. The same can be
|
|
accomplished by the &man.config.8; <option>-g</option> option, if
|
|
you are using the <quote>traditional</quote> way for building your kernels (See the <xref linkend="kernelconfig-building">
|
|
for more informations.).</para>
|
|
|
|
<programlisting>options MATH_EMULATE #Support for x87 emulation</programlisting>
|
|
|
|
<para>This line allows the kernel to simulate a math co-processor if
|
|
your computer does not have one (386 or 486SX). If you have a
|
|
486DX, or a 386 or 486SX (with a separate 387 or 487 chip), or
|
|
higher (&pentium;, &pentium; II, etc.), you can comment this line
|
|
out.</para>
|
|
|
|
<note>
|
|
<para>The normal math co-processor emulation routines that come with
|
|
&os; are <emphasis>not</emphasis> very accurate. If you do not
|
|
have a math co-processor, and you need the best accuracy, it is
|
|
recommended that you change this option to
|
|
<literal>GPL_MATH_EMULATE</literal> to use the GNU math support,
|
|
which is not included by default for licensing reasons.</para>
|
|
|
|
<para>In &os; 5.X, math emulation is disabled by default,
|
|
as older CPUs that do not have native floating point math support
|
|
are far less common, and in many cases not supported by the
|
|
<filename>GENERIC</filename> kernel without other additional options.</para></note>
|
|
|
|
<programlisting>options INET #InterNETworking</programlisting>
|
|
|
|
<para>Networking support. Leave this in, even if you do not plan to
|
|
be connected to a network. Most programs require at least loopback
|
|
networking (i.e., making network connections within your PC), so
|
|
this is essentially mandatory.</para>
|
|
|
|
<programlisting>options INET6 #IPv6 communications protocols</programlisting>
|
|
|
|
<para>This enables the IPv6 communication protocols.</para>
|
|
|
|
<programlisting>options FFS #Berkeley Fast Filesystem
|
|
options FFS_ROOT #FFS usable as root device [keep this!]</programlisting>
|
|
|
|
<para>This is the basic hard drive Filesystem. Leave it in if you
|
|
boot from the hard disk.</para>
|
|
|
|
<note><para>In &os; 5.X, <literal>FFS_ROOT</literal> is no longer
|
|
required.</para></note>
|
|
|
|
<programlisting>options UFS_ACL #Support for access control lists</programlisting>
|
|
|
|
<para>This option, present only in &os; 5.X, enables kernel support
|
|
for access control lists. This relies on the use of extended
|
|
attributes and <acronym>UFS2</acronym>, and the feature is described in detail
|
|
in the <xref linkend="fs-acl">. <acronym>ACL</acronym>s are enabled by default, and should not be
|
|
disabled in the kernel if they have been used previously on a file
|
|
system, as this will remove the access control lists changing the
|
|
way files are protected in unpredictable ways.</para>
|
|
|
|
<programlisting>options UFS_DIRHASH #Improve performance on big directories</programlisting>
|
|
|
|
<para>This option includes functionality to speed up disk
|
|
operations on large directories, at the expense of using
|
|
additional memory. You would normally keep this for a large
|
|
server, or interactive workstation, and remove it if you are
|
|
using &os; on a smaller system where memory is at a premium and
|
|
disk access speed is less important, such as a firewall.</para>
|
|
|
|
<programlisting>options SOFTUPDATES #Enable FFS Soft Updates support</programlisting>
|
|
|
|
<para>This option enables Soft Updates in the kernel, this will
|
|
help speed up write access on the disks. Even when this
|
|
functionality is provided by the kernel, it must be turned on
|
|
for specific disks. Review the output from &man.mount.8; to see
|
|
if Soft Updates is enabled for your system disks. If you do not
|
|
see the <literal>soft-updates</literal> option then you will
|
|
need to activate it using the &man.tunefs.8; (for existing
|
|
filesystems) or &man.newfs.8; (for new filesystems)
|
|
commands.</para>
|
|
|
|
<programlisting>options MFS #Memory Filesystem
|
|
options MD_ROOT #MD is a potential root device</programlisting>
|
|
|
|
<para>This is the memory-mapped Filesystem. This is basically a RAM
|
|
disk for fast storage of temporary files, useful if you have a lot
|
|
of swap space that you want to take advantage of. A perfect place
|
|
to mount an MFS partition is on the <filename>/tmp</filename>
|
|
directory, since many programs store temporary data here. To mount
|
|
an MFS RAM disk on <filename>/tmp</filename>, add the following line
|
|
to <filename>/etc/fstab</filename>:</para>
|
|
|
|
<informalexample>
|
|
<programlisting>/dev/ad1s2b /tmp mfs rw 0 0</programlisting>
|
|
</informalexample>
|
|
|
|
<para>Now you simply need to either reboot, or run the command
|
|
<command>mount /tmp</command>.</para>
|
|
|
|
<note><para>In &os; 5.X, &man.md.4;-backed UFS file systems are
|
|
used for memory file systems rather than MFS. Information on
|
|
configuring memory-backed file systems may be found in the manual pages
|
|
for &man.mdconfig.8; and &man.mdmfs.8;, and in <xref linkend="disks-virtual">. As a result, the
|
|
<literal>MFS</literal> option is no longer supported.</para></note>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>NFS</secondary>
|
|
</indexterm>
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>NFS_ROOT</secondary>
|
|
</indexterm>
|
|
<programlisting>options NFS #Network Filesystem
|
|
options NFS_ROOT #NFS usable as root device, NFS required</programlisting>
|
|
|
|
<para>The network Filesystem. Unless you plan to mount partitions
|
|
from a &unix; file server over TCP/IP, you can comment these
|
|
out.</para>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>MSDOSFS</secondary>
|
|
</indexterm>
|
|
<programlisting>options MSDOSFS #MSDOS Filesystem</programlisting>
|
|
|
|
<para>The &ms-dos; Filesystem. Unless you plan to mount a DOS formatted
|
|
hard drive partition at boot time, you can safely comment this out.
|
|
It will be automatically loaded the first time you mount a DOS
|
|
partition, as described above. Also, the excellent
|
|
<application>mtools</application> software (in the ports collection)
|
|
allows you to access DOS floppies without having to mount and
|
|
unmount them (and does not require <literal>MSDOSFS</literal> at
|
|
all).</para>
|
|
|
|
<programlisting>options CD9660 #ISO 9660 Filesystem
|
|
options CD9660_ROOT #CD-ROM usable as root, CD9660 required</programlisting>
|
|
|
|
<para>The ISO 9660 Filesystem for CDROMs. Comment it out if you do
|
|
not have a CDROM drive or only mount data CDs occasionally (since it
|
|
will be dynamically loaded the first time you mount a data CD).
|
|
Audio CDs do not need this Filesystem.</para>
|
|
|
|
<programlisting>options PROCFS #Process filesystem</programlisting>
|
|
|
|
<para>The process filesystem. This is a <quote>pretend</quote>
|
|
filesystem mounted on <filename>/proc</filename> which allows
|
|
programs like &man.ps.1; to give you more information on what
|
|
processes are running. In &os; 5.X, use of <literal>PROCFS</literal>
|
|
is not required under most circumstances, as most
|
|
debugging and monitoring tools have been adapted to run without
|
|
<literal>PROCFS</literal>. In addition, 5.X-CURRENT kernels
|
|
making use of <literal>PROCFS</literal> must now also include
|
|
support for <literal>PSEUDOFS</literal>:</para>
|
|
|
|
<programlisting>options PSEUDOFS #Pseudo-filesystem framework</programlisting>
|
|
|
|
<para><literal>PSEUDOFS</literal> is not available in &os; 4.X.
|
|
Unlike in &os; 4.X, new installations of &os; 5.X will not mount
|
|
the process file system by default.</para>
|
|
|
|
<programlisting>options COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!]</programlisting>
|
|
|
|
<para>Compatibility with 4.3BSD. Leave this in; some programs will
|
|
act strangely if you comment this out.</para>
|
|
|
|
<programlisting>options COMPAT_FREEBSD4 #Compatible with &os;4</programlisting>
|
|
|
|
<para>This option is required on &os; 5.X &i386; and Alpha systems
|
|
to support applications compiled on older versions of &os;
|
|
that use older system call interfaces. It is recommended that
|
|
this option be used on all &i386; and Alpha systems that may
|
|
run older applications; platforms that gained support only in
|
|
5.X, such as ia64 and &sparc64;, do not require this option.</para>
|
|
|
|
<programlisting>options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI</programlisting>
|
|
|
|
<para>This causes the kernel to pause for 15 seconds before probing
|
|
each SCSI device in your system. If you only have IDE hard drives,
|
|
you can ignore this, otherwise you will probably want to lower this
|
|
number, perhaps to 5 seconds, to speed up booting. Of course, if
|
|
you do this, and &os; has trouble recognizing your SCSI devices,
|
|
you will have to raise it back up.</para>
|
|
|
|
<programlisting>options UCONSOLE #Allow users to grab the console</programlisting>
|
|
|
|
<para>Allow users to grab the console, which is useful for X users.
|
|
For example, you can create a console <application>xterm</application>
|
|
by typing <command>xterm
|
|
-C</command>, which will display any &man.write.1;,
|
|
&man.talk.1;, and any other messages you receive, as well
|
|
as any console messages sent by the kernel.</para>
|
|
|
|
<note><para>In &os; 5.X, <literal>UCONSOLE</literal> is no
|
|
longer required.</para></note>
|
|
|
|
<programlisting>options USERCONFIG #boot -c editor</programlisting>
|
|
|
|
<para>This option allows you to boot the configuration editor from the
|
|
boot menu.</para>
|
|
|
|
<programlisting>options VISUAL_USERCONFIG #visual boot -c editor</programlisting>
|
|
|
|
<para>This option allows you to boot the visual configuration editor
|
|
from the boot menu.</para>
|
|
|
|
<note><para>From &os; versions 5.0 and later, the <literal>USERCONFIG</literal> options has
|
|
been depreciated in favor of the new &man.device.hints.5;
|
|
method. For more information on &man.device.hints.5; please
|
|
visit <xref linkend="device-hints">.</para></note>
|
|
|
|
<programlisting>options KTRACE #ktrace(1) support</programlisting>
|
|
|
|
<para>This enables kernel process tracing, which is useful in
|
|
debugging.</para>
|
|
|
|
<programlisting>options SYSVSHM #SYSV-style shared memory</programlisting>
|
|
|
|
<para>This option provides for System V shared memory. The most
|
|
common use of this is the XSHM extension in X, which many
|
|
graphics-intensive programs will automatically take advantage of for
|
|
extra speed. If you use X, you will definitely want to include
|
|
this.</para>
|
|
|
|
<programlisting>options SYSVSEM #SYSV-style semaphores</programlisting>
|
|
|
|
<para>Support for System V semaphores. Less commonly used but only
|
|
adds a few hundred bytes to the kernel.</para>
|
|
|
|
<programlisting>options SYSVMSG #SYSV-style message queues</programlisting>
|
|
|
|
<para>Support for System V messages. Again, only adds a few hundred
|
|
bytes to the kernel.</para>
|
|
|
|
<note>
|
|
<para>The &man.ipcs.1; command will list any processes using each of
|
|
these System V facilities.</para>
|
|
</note>
|
|
|
|
<programlisting>options P1003_1B #Posix P1003_1B real-time extensions
|
|
options _KPOSIX_PRIORITY_SCHEDULING</programlisting>
|
|
|
|
<para>Real-time extensions added in the 1993 &posix;. Certain
|
|
applications in the ports collection use these
|
|
(such as <application>&staroffice;</application>).</para>
|
|
|
|
<note><para>In &os; 5.X, all of this functionality is now
|
|
provided by the <literal>_KPOSIX_PRIORITY_SCHEDULING</literal>
|
|
option, and <literal>P1003_1B</literal> is no longer
|
|
required.</para></note>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>ICMP_BANDLIM</secondary>
|
|
</indexterm>
|
|
<indexterm>
|
|
<primary>Denial of Service (DoS)</primary>
|
|
</indexterm>
|
|
<programlisting>options ICMP_BANDLIM #Rate limit bad replies</programlisting>
|
|
|
|
<para>This option enables ICMP error response bandwidth limiting. You
|
|
typically want this option as it will help protect the machine from
|
|
denial of service packet attacks.</para>
|
|
|
|
<note><para>In &os; 5.X, this feature is enabled by default and
|
|
the <literal>ICMP_BANDLIM</literal> option is not required.
|
|
</para></note>
|
|
|
|
<indexterm>
|
|
<primary>kernel options</primary>
|
|
<secondary>SMP</secondary>
|
|
</indexterm>
|
|
<programlisting># To make an SMP kernel, the next two are needed
|
|
#options SMP # Symmetric MultiProcessor Kernel
|
|
#options APIC_IO # Symmetric (APIC) I/O</programlisting>
|
|
|
|
<para>The above are both required for SMP support.</para>
|
|
|
|
<programlisting>device isa</programlisting>
|
|
|
|
<para>All PCs supported by &os; have one of these. If you have an
|
|
IBM PS/2 (Micro Channel Architecture), &os; provides some
|
|
limited support at this time. For more information about the
|
|
MCA support, see
|
|
<filename>/usr/src/sys/i386/conf/LINT</filename>.</para>
|
|
|
|
<programlisting>device eisa</programlisting>
|
|
|
|
<para>Include this if you have an EISA motherboard. This enables
|
|
auto-detection and configuration support for all devices on the EISA
|
|
bus.</para>
|
|
|
|
<programlisting>device pci</programlisting>
|
|
|
|
<para>Include this if you have a PCI motherboard. This enables
|
|
auto-detection of PCI cards and gatewaying from the PCI to ISA
|
|
bus.</para>
|
|
|
|
<programlisting>device agp</programlisting>
|
|
|
|
<para>Include this if you have an AGP card in the system. This
|
|
will enable support for AGP, and AGP GART for boards which
|
|
have these features.</para>
|
|
|
|
<programlisting># Floppy drives
|
|
device fdc0 at isa? port IO_FD1 irq 6 drq 2
|
|
device fd0 at fdc0 drive 0
|
|
device fd1 at fdc0 drive 1</programlisting>
|
|
|
|
<para>This is the floppy drive controller. <literal>fd0</literal> is
|
|
the <devicename>A:</devicename> floppy drive, and
|
|
<literal>fd1</literal> is the <devicename>B:</devicename>
|
|
drive.</para>
|
|
|
|
<programlisting>device ata</programlisting>
|
|
|
|
<para>This driver supports all ATA and ATAPI devices. You only need
|
|
one <literal>device ata</literal> line for the kernel to detect all
|
|
PCI ATA/ATAPI devices on modern machines.</para>
|
|
|
|
<programlisting>device atadisk # ATA disk drives</programlisting>
|
|
|
|
<para>This is needed along with <literal>device ata</literal> for
|
|
ATA disk drives.</para>
|
|
|
|
<programlisting><anchor id="kernelconfig-atapi">
|
|
device atapicd # ATAPI CDROM drives</programlisting>
|
|
|
|
<para>This is needed along with <literal>device ata</literal> for
|
|
ATAPI CDROM drives.</para>
|
|
|
|
<programlisting>device atapifd # ATAPI floppy drives</programlisting>
|
|
|
|
<para>This is needed along with <literal>device ata</literal> for
|
|
ATAPI floppy drives.</para>
|
|
|
|
<programlisting>device atapist # ATAPI tape drives</programlisting>
|
|
|
|
<para>This is needed along with <literal>device ata</literal> for
|
|
ATAPI tape drives.</para>
|
|
|
|
<programlisting>options ATA_STATIC_ID #Static device numbering</programlisting>
|
|
|
|
<para>This makes the controller number static (like the old driver) or
|
|
else the device numbers are dynamically allocated.</para>
|
|
|
|
<programlisting># ATA and ATAPI devices
|
|
device ata0 at isa? port IO_WD1 irq 14
|
|
device ata1 at isa? port IO_WD2 irq 15</programlisting>
|
|
|
|
<para>Use the above for older, non-PCI systems.</para>
|
|
|
|
<programlisting># SCSI Controllers
|
|
device ahb # EISA AHA1742 family
|
|
device ahc # AHA2940 and onboard AIC7xxx devices
|
|
device amd # AMD 53C974 (Teckram DC-390(T))
|
|
device dpt # DPT Smartcache - See LINT for options!
|
|
device isp # Qlogic family
|
|
device ncr # NCR/Symbios Logic
|
|
device sym # NCR/Symbios Logic (newer chipsets)
|
|
|
|
device adv0 at isa?
|
|
device adw
|
|
device bt0 at isa?
|
|
device aha0 at isa?
|
|
device aic0 at isa?</programlisting>
|
|
|
|
<para>SCSI controllers. Comment out any you do not have in your
|
|
system. If you have an IDE only system, you can remove these
|
|
altogether.</para>
|
|
|
|
<programlisting># SCSI peripherals
|
|
device scbus # SCSI bus (required)
|
|
device da # Direct Access (disks)
|
|
device sa # Sequential Access (tape etc)
|
|
device cd # CD
|
|
device pass # Passthrough device (direct SCSI
|
|
access)</programlisting>
|
|
|
|
<para>SCSI peripherals. Again, comment out any you do not have, or if
|
|
you have only IDE hardware, you can remove them completely.</para>
|
|
|
|
<programlisting># RAID controllers
|
|
device ida # Compaq Smart RAID
|
|
device amr # AMI MegaRAID
|
|
device mlx # Mylex DAC960 family</programlisting>
|
|
|
|
<para>Supported RAID controllers. If you do not have any of these,
|
|
you can comment them out or remove them.</para>
|
|
|
|
<programlisting># atkbdc0 controls both the keyboard and the PS/2 mouse
|
|
device atkbdc0 at isa? port IO_KBD</programlisting>
|
|
|
|
<para>The keyboard controller (<literal>atkbdc</literal>) provides I/O
|
|
services for the AT keyboard and PS/2 style pointing devices. This
|
|
controller is required by the keyboard driver
|
|
(<literal>atkbd</literal>) and the PS/2 pointing device driver
|
|
(<literal>psm</literal>).</para>
|
|
|
|
<programlisting>device atkbd0 at atkbdc? irq 1</programlisting>
|
|
|
|
<para>The <literal>atkbd</literal> driver, together with
|
|
<literal>atkbdc</literal> controller, provides access to the AT 84
|
|
keyboard or the AT enhanced keyboard which is connected to the AT
|
|
keyboard controller.</para>
|
|
|
|
<programlisting>device psm0 at atkbdc? irq 12</programlisting>
|
|
|
|
<para>Use this device if your mouse plugs into the PS/2 mouse
|
|
port.</para>
|
|
|
|
<programlisting>device vga0 at isa?</programlisting>
|
|
|
|
<para>The video card driver.</para>
|
|
|
|
<programlisting># splash screen/screen saver
|
|
pseudo-device splash</programlisting>
|
|
|
|
<para>Splash screen at start up! Screen savers require this
|
|
too.</para>
|
|
|
|
<programlisting># syscons is the default console driver, resembling an SCO console
|
|
device sc0 at isa?</programlisting>
|
|
|
|
<para><literal>sc0</literal> is the default console driver, which
|
|
resembles a SCO console. Since most full-screen programs access the
|
|
console through a terminal database library like
|
|
<filename>termcap</filename>, it should not matter whether you use
|
|
this or <literal>vt0</literal>, the <literal>VT220</literal>
|
|
compatible console driver. When you log in, set your
|
|
<envar>TERM</envar> variable to <literal>scoansi</literal> if
|
|
full-screen programs have trouble running under this console.</para>
|
|
|
|
<programlisting># Enable this and PCVT_FREEBSD for pcvt vt220 compatible console driver
|
|
#device vt0 at isa?
|
|
#options XSERVER # support for X server on a vt console
|
|
#options FAT_CURSOR # start with block cursor
|
|
# If you have a ThinkPAD, uncomment this along with the rest of the PCVT lines
|
|
#options PCVT_SCANSET=2 # IBM keyboards are non-std</programlisting>
|
|
|
|
<para>This is a VT220-compatible console driver, backward compatible to
|
|
VT100/102. It works well on some laptops which have hardware
|
|
incompatibilities with <literal>sc0</literal>. Also set your
|
|
<envar>TERM</envar> variable to <literal>vt100</literal> or
|
|
<literal>vt220</literal> when you log in. This driver might also
|
|
prove useful when connecting to a large number of different machines
|
|
over the network, where <filename>termcap</filename> or
|
|
<filename>terminfo</filename> entries for the <literal>sc0</literal>
|
|
device are often not available — <literal>vt100</literal>
|
|
should be available on virtually any platform.</para>
|
|
|
|
<programlisting># Power management support (see LINT for more options)
|
|
device apm0 at nexus? disable flags 0x20 # Advanced Power Management</programlisting>
|
|
|
|
<para>Advanced Power Management support. Useful for laptops.</para>
|
|
|
|
<programlisting># PCCARD (PCMCIA) support
|
|
device card
|
|
device pcic0 at isa? irq 10 port 0x3e0 iomem 0xd0000
|
|
device pcic1 at isa? irq 11 port 0x3e2 iomem 0xd4000 disable</programlisting>
|
|
|
|
<para>PCMCIA support. You want this if you are using a
|
|
laptop.</para>
|
|
|
|
<programlisting># Serial (COM) ports
|
|
device sio0 at isa? port IO_COM1 flags 0x10 irq 4
|
|
device sio1 at isa? port IO_COM2 irq 3
|
|
device sio2 at isa? disable port IO_COM3 irq 5
|
|
device sio3 at isa? disable port IO_COM4 irq 9</programlisting>
|
|
|
|
<para>These are the four serial ports referred to as COM1 through COM4
|
|
in the &ms-dos/&windows; world.</para>
|
|
|
|
<note>
|
|
<para>If you have an internal modem on COM4 and a serial port at
|
|
COM2, you will have to change the IRQ of the modem to 2 (for
|
|
obscure technical reasons, IRQ2 = IRQ 9) in order to access it
|
|
from &os;. If you have a multiport serial card, check the
|
|
manual page for &man.sio.4; for more information on the proper
|
|
values for these lines. Some video cards (notably those based on
|
|
S3 chips) use IO addresses in the form of
|
|
<literal>0x*2e8</literal>, and since many cheap serial cards do
|
|
not fully decode the 16-bit IO address space, they clash with
|
|
these cards making the COM4 port practically unavailable.</para>
|
|
|
|
<para>Each serial port is required to have a unique IRQ (unless you
|
|
are using one of the multiport cards where shared interrupts are
|
|
supported), so the default IRQs for COM3 and COM4 cannot be
|
|
used.</para>
|
|
</note>
|
|
|
|
<programlisting># Parallel port
|
|
device ppc0 at isa? irq 7</programlisting>
|
|
|
|
<para>This is the ISA-bus parallel port interface.</para>
|
|
|
|
<programlisting>device ppbus # Parallel port bus (required)</programlisting>
|
|
|
|
<para>Provides support for the parallel port bus.</para>
|
|
|
|
<programlisting>device lpt # Printer</programlisting>
|
|
|
|
<para>Support for parallel port printers.</para>
|
|
|
|
<note>
|
|
<para>All three of the above are required to enable parallel printer
|
|
support.</para>
|
|
</note>
|
|
|
|
<programlisting>device plip # TCP/IP over parallel</programlisting>
|
|
|
|
<para>This is the driver for the parallel network interface.</para>
|
|
|
|
<programlisting>device ppi # Parallel port interface device</programlisting>
|
|
|
|
<para>The general-purpose I/O (<quote>geek port</quote>) + IEEE1284
|
|
I/O.</para>
|
|
|
|
<programlisting>#device vpo # Requires scbus and da</programlisting>
|
|
|
|
<indexterm><primary>zip drive</primary></indexterm>
|
|
<para>This is for an Iomega Zip drive. It requires
|
|
<literal>scbus</literal> and <literal>da</literal> support. Best
|
|
performance is achieved with ports in EPP 1.9 mode.</para>
|
|
|
|
<programlisting># PCI Ethernet NICs.
|
|
device de # DEC/Intel DC21x4x (<quote>Tulip</quote>)
|
|
device fxp # Intel EtherExpress PRO/100B (82557, 82558)
|
|
device tx # SMC 9432TX (83c170 <quote>EPIC</quote>)
|
|
device vx # 3Com 3c590, 3c595 (<quote>Vortex</quote>)
|
|
device wx # Intel Gigabit Ethernet Card (<quote>Wiseman</quote>)</programlisting>
|
|
|
|
<para>Various PCI network card drivers. Comment out or remove any of
|
|
these not present in your system.</para>
|
|
|
|
<programlisting># PCI Ethernet NICs that use the common MII bus controller code.
|
|
device miibus # MII bus support</programlisting>
|
|
|
|
<para>MII bus support is required for some PCI 10/100 Ethernet NICs,
|
|
namely those which use MII-compliant transceivers or implement
|
|
transceiver control interfaces that operate like an MII. Adding
|
|
<literal>device miibus</literal> to the kernel config pulls in
|
|
support for the generic miibus API and all of the PHY drivers,
|
|
including a generic one for PHYs that are not specifically handled
|
|
by an individual driver.</para>
|
|
|
|
<programlisting>device dc # DEC/Intel 21143 and various workalikes
|
|
device rl # RealTek 8129/8139
|
|
device sf # Adaptec AIC-6915 (<quote>Starfire</quote>)
|
|
device sis # Silicon Integrated Systems SiS 900/SiS 7016
|
|
device ste # Sundance ST201 (D-Link DFE-550TX)
|
|
device tl # Texas Instruments ThunderLAN
|
|
device vr # VIA Rhine, Rhine II
|
|
device wb # Winbond W89C840F
|
|
device xl # 3Com 3c90x (<quote>Boomerang</quote>, <quote>Cyclone</quote>)</programlisting>
|
|
|
|
<para>Drivers that use the MII bus controller code.</para>
|
|
|
|
<programlisting># ISA Ethernet NICs.
|
|
device ed0 at isa? port 0x280 irq 10 iomem 0xd8000
|
|
device ex
|
|
device ep
|
|
# WaveLAN/IEEE 802.11 wireless NICs. Note: the WaveLAN/IEEE really
|
|
# exists only as a PCMCIA device, so there is no ISA attachment needed
|
|
# and resources will always be dynamically assigned by the pccard code.
|
|
device wi
|
|
# Aironet 4500/4800 802.11 wireless NICs. Note: the declaration below will
|
|
# work for PCMCIA and PCI cards, as well as ISA cards set to ISA PnP
|
|
# mode (the factory default). If you set the switches on your ISA
|
|
# card for a manually chosen I/O address and IRQ, you must specify
|
|
# those parameters here.
|
|
device an
|
|
# The probe order of these is presently determined by i386/isa/isa_compat.c.
|
|
device ie0 at isa? port 0x300 irq 10 iomem 0xd0000
|
|
device fe0 at isa? port 0x300
|
|
device le0 at isa? port 0x300 irq 5 iomem 0xd0000
|
|
device lnc0 at isa? port 0x280 irq 10 drq 0
|
|
device cs0 at isa? port 0x300
|
|
device sn0 at isa? port 0x300 irq 10
|
|
# requires PCCARD (PCMCIA) support to be activated
|
|
#device xe0 at isa?</programlisting>
|
|
|
|
<para>ISA Ethernet drivers. See
|
|
<filename>/usr/src/sys/i386/conf/LINT</filename> for which cards are
|
|
supported by which driver.</para>
|
|
|
|
<programlisting>pseudo-device ether # Ethernet support</programlisting>
|
|
|
|
<para><literal>ether</literal> is only needed if you have an Ethernet
|
|
card. It includes generic Ethernet protocol code.</para>
|
|
|
|
<programlisting>pseudo-device sl 1 # Kernel SLIP</programlisting>
|
|
|
|
<para><literal>sl</literal> is for SLIP support. This has been almost
|
|
entirely supplanted by PPP, which is easier to set up, better suited
|
|
for modem-to-modem connection, and more powerful. The
|
|
<replaceable>number</replaceable> after <literal>sl</literal>
|
|
specifies how many simultaneous SLIP sessions to support.</para>
|
|
|
|
<programlisting>pseudo-device ppp 1 # Kernel PPP</programlisting>
|
|
|
|
<para>This is for kernel PPP support for dial-up connections. There
|
|
is also a version of PPP implemented as a userland application that
|
|
uses <literal>tun</literal> and offers more flexibility and features
|
|
such as demand dialing. The <replaceable>number</replaceable> after
|
|
<literal>ppp</literal> specifies how many simultaneous PPP
|
|
connections to support.</para>
|
|
|
|
<programlisting>pseudo-device tun # Packet tunnel.</programlisting>
|
|
|
|
<para>This is used by the userland PPP software. A
|
|
<replaceable>number</replaceable> after <literal>tun</literal>
|
|
specifies the number of simultaneous PPP sessions to support. See
|
|
the <link linkend="userppp">PPP</link> section of this book for more
|
|
information.</para>
|
|
|
|
<programlisting><anchor id="kernelconfig-ptys">
|
|
pseudo-device pty # Pseudo-ttys (telnet etc)</programlisting>
|
|
|
|
<para>This is a <quote>pseudo-terminal</quote> or simulated login port.
|
|
It is used by incoming <command>telnet</command> and
|
|
<command>rlogin</command> sessions,
|
|
<application>xterm</application>, and some other applications such
|
|
as <application>Emacs</application>. A
|
|
<replaceable>number</replaceable> after <literal>pty</literal> indicates the number of
|
|
<literal>pty</literal>s to create. If you need more than the
|
|
default of 16 simultaneous <application>xterm</application> windows
|
|
and/or remote logins, be sure to increase this number accordingly,
|
|
up to a maximum of 256.</para>
|
|
|
|
<programlisting>pseudo-device md # Memory <quote>disks</quote></programlisting>
|
|
|
|
<para>Memory disk pseudo-devices.</para>
|
|
|
|
<programlisting>pseudo-device gif</programlisting>
|
|
|
|
<para>or</para>
|
|
|
|
<programlisting>pseudo-device gif 4 # IPv6 and IPv4 tunneling</programlisting>
|
|
|
|
<para>This implements IPv6 over IPv4 tunneling, IPv4 over IPv6 tunneling,
|
|
IPv4 over IPv4 tunneling, and IPv6 over IPv6 tunneling. Beginning with
|
|
&os; 4.4 the <literal>gif</literal> device is
|
|
<quote>auto-cloning</quote>, and you should use the first example
|
|
(without the number after <literal>gif</literal>). Earlier versions of
|
|
&os; require the number.</para>
|
|
|
|
<programlisting>pseudo-device faith 1 # IPv6-to-IPv4 relaying (translation)</programlisting>
|
|
|
|
<para>This pseudo-device captures packets that are sent to it and
|
|
diverts them to the IPv4/IPv6 translation daemon.</para>
|
|
|
|
<programlisting># The `bpf' pseudo-device enables the Berkeley Packet Filter.
|
|
# Be aware of the administrative consequences of enabling this!
|
|
pseudo-device bpf # Berkeley packet filter</programlisting>
|
|
|
|
<para>This is the Berkeley Packet Filter. This pseudo-device allows
|
|
network interfaces to be placed in promiscuous mode, capturing every
|
|
packet on a broadcast network (e.g., an Ethernet). These packets
|
|
can be captured to disk and or examined with the &man.tcpdump.1;
|
|
program.</para>
|
|
|
|
<note>
|
|
<para>The <literal>bpf pseudo-device</literal> is also used by
|
|
&man.dhclient.8; to obtain the IP address of the default router
|
|
(gateway) and so on. If you use DHCP, leave this
|
|
uncommented.</para>
|
|
</note>
|
|
|
|
<programlisting># USB support
|
|
#device uhci # UHCI PCI->USB interface
|
|
#device ohci # OHCI PCI->USB interface
|
|
#device usb # USB Bus (required)
|
|
#device ugen # Generic
|
|
#device uhid # <quote>Human Interface Devices</quote>
|
|
#device ukbd # Keyboard
|
|
#device ulpt # Printer
|
|
#device umass # Disks/Mass storage - Requires scbus and da
|
|
#device ums # Mouse
|
|
# USB Ethernet, requires mii
|
|
#device aue # ADMtek USB ethernet
|
|
#device cue # CATC USB ethernet
|
|
#device kue # Kawasaki LSI USB ethernet</programlisting>
|
|
|
|
<para>Support for various USB devices.</para>
|
|
|
|
<para>For more information and additional devices supported by
|
|
&os;, see
|
|
<filename>/usr/src/sys/i386/conf/LINT</filename>.</para>
|
|
|
|
<sect2>
|
|
<title>Large Memory Configurations (<acronym>PAE</acronym>)</title>
|
|
<indexterm>
|
|
<primary>
|
|
Physical Address Extensions (<acronym>PAE</acronym>)
|
|
</primary>
|
|
<secondary>
|
|
Large Memory Configurations
|
|
</secondary>
|
|
</indexterm>
|
|
|
|
<para>Large memory configuration machines require access to
|
|
more than the 4 gigabyte limit on User+Kernel Virtual
|
|
Address (<acronym>KVA</acronym>) space. Due to this
|
|
limitation, Intel added support for 36-bit physical address
|
|
space access in the &pentium; Pro and later line of CPUs.</para>
|
|
|
|
<para>The Physical Address Extension (<acronym>PAE</acronym>)
|
|
capability of the &intel; &pentium; Pro and later CPUs
|
|
allows memory configurations of up to 64 gigabytes.
|
|
&os; provides support for this capability via the
|
|
<option>PAE</option> kernel configuration option, available
|
|
in the 4.X series of &os; beginning with 4.9-RELEASE and
|
|
in the 5.X series of &os; beginning with 5.1-RELEASE. Due to
|
|
the limitations of the Intel memory architecture, no distinction
|
|
is made for memory above or below 4 gigabytes. Memory allocated
|
|
above 4 gigabytes is simply added to the pool of available
|
|
memory.</para>
|
|
|
|
<para>To enable <acronym>PAE</acronym> support in the kernel,
|
|
simply add the following line to your kernel configuration
|
|
file:</para>
|
|
|
|
<programlisting>options PAE</programlisting>
|
|
|
|
<note>
|
|
<para>The <acronym>PAE</acronym> support in &os; is only
|
|
available for &intel; IA-32 processors. It should also be
|
|
noted, that the <acronym>PAE</acronym> support in &os; has
|
|
not received wide testing, and should be considered beta
|
|
quality compared to other stable features of &os;.</para>
|
|
</note>
|
|
|
|
<para>PAE support in &os; has a few limitations:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>A process is not able to access more than 4
|
|
gigabytes of VM space.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><acronym>KLD</acronym> modules cannot be loaded into
|
|
a <acronym>PAE</acronym> enabled kernel, due to the
|
|
differences in the build framework of a module and the
|
|
kernel.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Device drivers that do not use the &man.bus.dma.9;
|
|
interface will cause data corruption in a
|
|
<acronym>PAE</acronym> enabled kernel and are not
|
|
recommended for use. For this reason, the
|
|
<filename>PAE</filename> kernel
|
|
configuration file is provided in &os; 5.X, which
|
|
excludes all drivers not known to work in a PAE enabled
|
|
kernel.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Some system tunables determine memory resource usage
|
|
by the amount of available physical memory. Such
|
|
tunables can unnecessarily over-allocate due to the
|
|
large memory nature of a <acronym>PAE</acronym> system.
|
|
One such example is the <option>kern.maxvnodes</option>
|
|
sysctl, which controls the maximum number of vnodes allowed
|
|
in the kernel. It is advised to adjust this and other
|
|
such tunables to a reasonable value.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>It might be necessary to increase the kernel virtual
|
|
address (<acronym>KVA</acronym>) space or to reduce the
|
|
amount of specific kernel resource that is heavily used
|
|
(see above) in order to avoid <acronym>KVA</acronym>
|
|
exhaustion. The <option>KVA_PAGES</option> kernel option
|
|
can be used for increasing the
|
|
<acronym>KVA</acronym> space.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>For performance and stability concerns, it is advised to
|
|
consult the &man.tuning.7; manual page. The &man.pae.4;
|
|
manual page contains up-to-date information on &os;'s
|
|
<acronym>PAE</acronym> support.</para>
|
|
</sect2>
|
|
</sect1>
|
|
|
|
<sect1 id="kernelconfig-nodes">
|
|
<title>Making Device Nodes</title>
|
|
|
|
<indexterm><primary>device nodes</primary></indexterm>
|
|
<indexterm>
|
|
<primary><command>MAKEDEV</command></primary>
|
|
</indexterm>
|
|
|
|
<note><para>If you are running &os; 5.0 or later
|
|
you can safely skip this section. These versions use
|
|
&man.devfs.5; to allocate device nodes transparently for the user.</para></note>
|
|
|
|
<para>Almost every device in the kernel has a corresponding
|
|
<quote>node</quote> entry in the <filename>/dev</filename> directory.
|
|
These nodes look like regular files, but are actually special
|
|
entries into the kernel which programs use to access the device.
|
|
The shell script <filename>/dev/MAKEDEV</filename>, which is
|
|
executed when you first install the operating system, creates
|
|
nearly all of the device nodes supported. However, it does not
|
|
create <emphasis>all</emphasis> of them, so when you add support for
|
|
a new device, it pays to make sure that the appropriate entries are
|
|
in this directory, and if not, add them. Here is a simple
|
|
example:</para>
|
|
|
|
<para>Suppose you add the IDE CD-ROM support to the kernel. The line
|
|
to add is:</para>
|
|
|
|
<programlisting>device acd0</programlisting>
|
|
|
|
<para>This means that you should look for some entries that start with
|
|
<filename>acd0</filename> in the <filename>/dev</filename>
|
|
directory, possibly followed by a letter, such as
|
|
<literal>c</literal>, or preceded by the letter
|
|
<literal>r</literal>, which means a <quote>raw</quote> device. It
|
|
turns out that those files are not there, so you must change to the
|
|
<filename>/dev</filename> directory and type:</para>
|
|
|
|
<indexterm>
|
|
<primary><command>MAKEDEV</command></primary></indexterm>
|
|
<screen>&prompt.root; <userinput>sh MAKEDEV acd0</userinput></screen>
|
|
|
|
<para>When this script finishes, you will find that there are now
|
|
<filename>acd0c</filename> and <filename>racd0c</filename> entries
|
|
in <filename>/dev</filename> so you know that it executed
|
|
correctly.</para>
|
|
|
|
<para>For sound cards, the following command creates the appropriate
|
|
entries:</para>
|
|
|
|
<screen>&prompt.root; <userinput>sh MAKEDEV snd0</userinput></screen>
|
|
|
|
<note>
|
|
<para>When creating device nodes for devices such as sound cards, if
|
|
other people have access to your machine, it may be desirable to
|
|
protect the devices from outside access by adding them to the
|
|
<filename>/etc/fbtab</filename> file. See &man.fbtab.5; for more
|
|
information.</para>
|
|
</note>
|
|
|
|
<para>Follow this simple procedure for any other
|
|
non-<filename>GENERIC</filename> devices which do not have
|
|
entries.</para>
|
|
|
|
<note>
|
|
<para>All SCSI controllers use the same set of
|
|
<filename>/dev</filename> entries, so you do not need to create
|
|
these. Also, network cards and SLIP/PPP pseudo-devices do not
|
|
have entries in <filename>/dev</filename> at all, so you do not
|
|
have to worry about these either.</para>
|
|
</note>
|
|
</sect1>
|
|
|
|
<sect1 id="kernelconfig-trouble">
|
|
<title>If Something Goes Wrong</title>
|
|
|
|
<para>There are five categories of trouble that can occur when
|
|
building a custom kernel. They are:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><command>config</command> fails:</term>
|
|
|
|
<listitem>
|
|
<para>If the &man.config.8; command fails when you
|
|
give it your kernel description, you have probably made a
|
|
simple error somewhere. Fortunately,
|
|
&man.config.8; will print the line number that it
|
|
had trouble with, so you can quickly skip to it with
|
|
<application>vi</application>. For example, if you see:</para>
|
|
|
|
<screen>config: line 17: syntax error</screen>
|
|
|
|
<para>You can skip to the problem in <application>vi</application> by
|
|
typing <command>17G</command> in command mode. Make sure the
|
|
keyword is typed correctly, by comparing it to the
|
|
<filename>GENERIC</filename> kernel or another
|
|
reference.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><command>make</command> fails:</term>
|
|
|
|
<listitem>
|
|
<para>If the <command>make</command> command fails, it usually
|
|
signals an error in your kernel description, but not severe
|
|
enough for &man.config.8; to catch it. Again, look
|
|
over your configuration, and if you still cannot resolve the
|
|
problem, send mail to the &a.questions; with your kernel
|
|
configuration, and it should be diagnosed very quickly.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>Installing the new kernel fails:</term>
|
|
|
|
<listitem>
|
|
<para>If the kernel compiled fine, but failed to install
|
|
(the <command>make install</command> or
|
|
<command>make installkernel</command> command failed),
|
|
the first thing to check is if your system is running at
|
|
securelevel 1 or higher (see &man.init.8;). The kernel
|
|
installation tries to remove the immutable flag from
|
|
your kernel and set the immutable flag on the new one.
|
|
Since securelevel 1 or higher prevents unsetting the immutable
|
|
flag for any files on the system, the kernel installation needs
|
|
to be performed at securelevel 0 or lower.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>The kernel does not boot:<anchor
|
|
id="kernelconfig-noboot"></term>
|
|
|
|
<listitem>
|
|
<para>If your new kernel does not boot, or fails to
|
|
recognize your devices, do not panic! Fortunately, &os; has
|
|
an excellent mechanism for recovering from incompatible
|
|
kernels. Simply choose the kernel you want to boot from at
|
|
the &os; boot loader. You can access this when the system
|
|
counts down from 10. Hit any key except for the
|
|
<keycap>Enter</keycap> key, type <command>unload</command>
|
|
and then type
|
|
<command>boot <replaceable>kernel.old</replaceable></command>,
|
|
or the filename of any other kernel that will boot properly.
|
|
When reconfiguring a kernel, it is always a good idea to keep
|
|
a kernel that is known to work on hand.</para>
|
|
|
|
<para>After booting with a good kernel you can check over your
|
|
configuration file and try to build it again. One helpful
|
|
resource is the <filename>/var/log/messages</filename> file
|
|
which records, among other things, all of the kernel messages
|
|
from every successful boot. Also, the &man.dmesg.8; command
|
|
will print the kernel messages from the current boot.</para>
|
|
|
|
<note>
|
|
<para>If you are having trouble building a kernel, make sure
|
|
to keep a <filename>GENERIC</filename>, or some other kernel
|
|
that is known to work on hand as a different name that will
|
|
not get erased on the next build. You cannot rely on
|
|
<filename>kernel.old</filename> because when installing a
|
|
new kernel, <filename>kernel.old</filename> is overwritten
|
|
with the last installed kernel which may be non-functional.
|
|
Also, as soon as possible, move the working kernel to the
|
|
proper <filename>kernel</filename> location or commands such
|
|
as &man.ps.1; will not work properly. The proper command to
|
|
<quote>unlock</quote> the kernel file that
|
|
<command>make</command> installs (in order to move another
|
|
kernel back permanently) is:</para>
|
|
|
|
<screen>&prompt.root; <userinput>chflags noschg /kernel</userinput></screen>
|
|
|
|
<para>If you find you cannot do this, you are probably running
|
|
at a &man.securelevel.8; greater than zero. Edit
|
|
<literal>kern_securelevel</literal> in
|
|
<filename>/etc/rc.conf</filename> and set it to
|
|
<literal>-1</literal>, then reboot. You can change it back
|
|
to its previous setting when you are happy with your new
|
|
kernel.</para>
|
|
|
|
<para>And, if you want to <quote>lock</quote> your new kernel
|
|
into place, or any file for that matter, so that it cannot
|
|
be moved or tampered with:</para>
|
|
|
|
<screen>&prompt.root; <userinput>chflags schg /kernel</userinput></screen>
|
|
|
|
<para>In &os; 5.X, kernels are not installed with the
|
|
system immutable flag, so this is unlikely to be the source
|
|
of the problem you are experiencing.</para></note>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>The kernel works, but &man.ps.1; does not work
|
|
any more:</term>
|
|
|
|
<listitem>
|
|
<para>If you have installed a different version of the kernel
|
|
from the one that the system utilities have been built with,
|
|
for example, a 4.X kernel on a 3.X system, many system-status
|
|
commands like &man.ps.1; and &man.vmstat.8; will not work any
|
|
more. You must recompile the <filename>libkvm</filename>
|
|
library as well as these utilities. This is one reason it is
|
|
not normally a good idea to use a different version of the
|
|
kernel from the rest of the operating system.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</sect1>
|
|
</chapter>
|
|
|
|
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|
|
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|
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|
|
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|
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|
|
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|
|
sgml-always-quote-attributes: t
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sgml-parent-document: ("../book.sgml" "part" "chapter")
|
|
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|
|
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|
|
|