[3f8be484] | 1 | <?xml version="1.0" encoding="ISO-8859-1"?> |
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[aa18ac0] | 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
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| 3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ |
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[3f8be484] | 4 | <!ENTITY % general-entities SYSTEM "../../general.ent"> |
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| 5 | %general-entities; |
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| 6 | ]> |
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| 7 | |
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| 8 | <sect1 id="ch-bootable-kernel" role="wrap"> |
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| 9 | <?dbhtml filename="kernel.html"?> |
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| 10 | |
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[7f8996d] | 11 | <title>Linux-&linux-version2;</title> |
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[3f8be484] | 12 | |
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| 13 | <indexterm zone="ch-bootable-kernel"> |
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| 14 | <primary sortas="a-Linux">Linux</primary> |
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| 15 | </indexterm> |
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| 16 | |
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| 17 | <sect2 role="package"><title/> |
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| 18 | <para>The Linux package contains the Linux kernel.</para> |
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| 19 | |
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| 20 | </sect2> |
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| 21 | |
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| 22 | <sect2 role="installation"> |
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| 23 | <title>Installation of the kernel</title> |
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| 24 | |
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| 25 | <para os="a">Building the kernel involves a few steps—configuration, |
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| 26 | compilation, and installation. Read the <filename>README</filename> |
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| 27 | file in the kernel source tree for alternative methods to the way this |
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| 28 | book configures the kernel.</para> |
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| 29 | |
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[f7bd24c] | 30 | <para os="p1">Apply the latest Linux sublevel patch:</para> |
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| 31 | |
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| 32 | <screen os="p2"><userinput>xzcat ../&linux-sublevel-patch; | patch -Np1 -i -</userinput></screen> |
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| 33 | |
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[3f8be484] | 34 | <para os="b">Prepare for compilation by running the following command:</para> |
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| 35 | |
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| 36 | <screen os="c"><userinput>make mrproper</userinput></screen> |
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| 37 | |
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| 38 | <para os="d">This ensures that the kernel tree is absolutely clean. The |
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| 39 | kernel team recommends that this command be issued prior to each |
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| 40 | kernel compilation. Do not rely on the source tree being clean after |
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| 41 | un-tarring.</para> |
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| 42 | |
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[573ee7a] | 43 | <note os="kc"><para>A good starting place for setting up the kernel |
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| 44 | configuration is to run <command>make defconfig</command>. This will set the base configuration to a good state that takes your current system |
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| 45 | architecture into account.</para> |
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[eaeb8faf] | 46 | |
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[573ee7a] | 47 | <para>Be sure to enable or disable following features or the system might |
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| 48 | not work correctly or boot at all. Refer to |
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| 49 | <filename>/usr/share/doc/systemd-&systemd-version;/README</filename>:</para> |
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[eaeb8faf] | 50 | |
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| 51 | <screen role="nodump">General setup ---> |
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[573ee7a] | 52 | [*] open by fhandle syscalls |
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[ca8dde0] | 53 | [ ] Auditing support |
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[eaeb8faf] | 54 | [*] Control Group support |
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| 55 | Processor type and features ---> |
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| 56 | [*] Enable seccomp to safely compute untrusted bytecode |
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| 57 | Networking support ---> |
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| 58 | Networking options ---> |
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| 59 | <*> The IPv6 protocol |
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| 60 | Device Drivers ---> |
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| 61 | Generic Driver Options ---> |
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| 62 | () path to uevent helper |
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| 63 | [*] Maintain a devtmpfs filesystem to mount at /dev |
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| 64 | [ ] Fallback user-helper invocation for firmware loading |
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| 65 | File systems ---> |
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| 66 | [*] Inotify support for userspace |
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| 67 | <*> Kernel automounter version 4 support (also supports v3) |
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| 68 | Pseudo filesystems ---> |
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| 69 | [*] Tmpfs POSIX Access Control Lists |
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[ca8dde0] | 70 | [*] Tmpfs extended attributes |
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| 71 | Firmware Drivers ---> |
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| 72 | EFI (Extensible Firmware Interface) Support ---> |
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| 73 | <*> EFI Variable Support via sysfs |
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| 74 | -*- Enable the block layer ---> |
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| 75 | Partition Types ---> |
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| 76 | [*] Advanced partition selection |
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| 77 | [*] EFI GUID Partition support |
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| 78 | Kernel Hacking ---> |
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| 79 | [*] Collect scheduler debugging info |
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| 80 | [*] Collect scheduler statistics</screen></note> |
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[eaeb8faf] | 81 | |
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[573ee7a] | 82 | <note os="kd"><para>While "The IPv6 Protocol" is not strictly required, it |
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[ca8dde0] | 83 | is highly recommended by the Systemd developers. "EFI Variable support" and |
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| 84 | "EFI GUID Partition support" are for UEFI systems. "Collect scheduler |
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| 85 | debugging info" and "Collect scheduler statistics" is for systemd-bootchart. |
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| 86 | </para></note> |
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[eaeb8faf] | 87 | |
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[77e81f1] | 88 | <para os="h">Configure the kernel via a menu-driven interface. |
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[573ee7a] | 89 | CBLFS has some information regarding particular kernel configuration |
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| 90 | requirements of packages outside of CLFS at <ulink |
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[0d4607d] | 91 | url="&cblfs-root;"/>:</para> |
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[3f8be484] | 92 | |
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| 93 | <screen os="i"><userinput>make menuconfig</userinput></screen> |
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| 94 | |
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| 95 | <para os="j">Alternatively, <command>make oldconfig</command> may be more |
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| 96 | appropriate in some situations. See the <filename>README</filename> |
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| 97 | file for more information.</para> |
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| 98 | |
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| 99 | <para os="k">If desired, skip kernel configuration by copying the kernel |
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| 100 | config file, <filename>.config</filename>, from the host system |
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| 101 | (assuming it is available) to the root directory of the unpacked kernel |
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| 102 | sources. However, we do not recommend this option. It is often better |
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| 103 | to explore all the configuration menus and create the kernel configuration |
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| 104 | from scratch.</para> |
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| 105 | |
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| 106 | <para os="m">Compile the kernel image and modules:</para> |
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| 107 | |
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| 108 | <screen os="n"><userinput>make</userinput></screen> |
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| 109 | |
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[4e982a0] | 110 | <para os="o">If using kernel modules, a configuration file in |
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| 111 | <filename class="directory">/etc/modprobe.d</filename> file may be needed. |
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[3f8be484] | 112 | Information pertaining to modules and kernel configuration is |
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| 113 | located in the kernel documentation in the <filename |
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| 114 | class="directory">Documentation</filename> directory of the kernel |
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[4e982a0] | 115 | sources tree. Also, <filename>modprobe.d(5)</filename> may |
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[3f8be484] | 116 | be of interest.</para> |
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| 117 | |
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| 118 | <para os="s">Install the modules, if the kernel configuration uses |
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| 119 | them:</para> |
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| 120 | |
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| 121 | <screen os="t"><userinput>make modules_install</userinput></screen> |
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| 122 | |
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[22211c7] | 123 | <para os="s2">Install the firmware, if the kernel configuration uses |
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| 124 | them:</para> |
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| 125 | |
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| 126 | <screen os="t2"><userinput>make firmware_install</userinput></screen> |
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| 127 | |
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[3f8be484] | 128 | <para os="u">After kernel compilation is complete, additional steps are |
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| 129 | required to complete the installation. Some files need to be copied to |
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| 130 | the <filename class="directory">/boot</filename> directory.</para> |
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| 131 | |
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| 132 | <para os="v">Issue the following command to install the kernel:</para> |
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| 133 | |
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[7f8996d] | 134 | <screen><userinput>cp -v arch/i386/boot/bzImage /boot/vmlinuz-clfs-&linux-version2;</userinput></screen> |
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[3f8be484] | 135 | |
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| 136 | <para os="w"><filename>System.map</filename> is a symbol file for the kernel. |
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| 137 | It maps the function entry points of every function in the kernel API, |
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| 138 | as well as the addresses of the kernel data structures for the running |
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| 139 | kernel. Issue the following command to install the map file:</para> |
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| 140 | |
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[7f8996d] | 141 | <screen os="w1"><userinput>cp -v System.map /boot/System.map-&linux-version2;</userinput></screen> |
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[3f8be484] | 142 | |
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| 143 | <para os="x">The kernel configuration file <filename>.config</filename> |
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| 144 | produced by the <command>make menuconfig</command> step above contains |
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| 145 | all the configuration selections for the kernel that was just compiled. |
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| 146 | It is a good idea to keep this file for future reference:</para> |
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| 147 | |
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[7f8996d] | 148 | <screen os="x1"><userinput>cp -v .config /boot/config-&linux-version2;</userinput></screen> |
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[3f8be484] | 149 | |
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| 150 | <para os="y">It is important to note that the files in the kernel source |
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| 151 | directory are not owned by <systemitem class="username">root</systemitem>. |
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| 152 | Whenever a package is unpacked as user <systemitem |
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[a7fa075] | 153 | class="username">root</systemitem> (like we do inside the final-system |
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| 154 | build environment), the files have the user and group IDs of whatever |
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[3f8be484] | 155 | they were on the packager's computer. This is usually not a problem |
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| 156 | for any other package to be installed because the source tree is |
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| 157 | removed after the installation. However, the Linux source tree is |
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[a7fa075] | 158 | often retained for a long time. Because of this, there is a chance |
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[3f8be484] | 159 | that whatever user ID the packager used will be assigned to somebody |
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| 160 | on the machine. That person would then have write access to the kernel |
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| 161 | source.</para> |
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| 162 | |
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[43daa01] | 163 | <para os="y1">If the kernel source tree is going to retained, run |
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[3f8be484] | 164 | <command>chown -R 0:0</command> on the <filename |
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[43daa01] | 165 | class="directory">linux-&linux-version;</filename> directory to |
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[3f8be484] | 166 | ensure all files are owned by user <systemitem |
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| 167 | class="username">root</systemitem>.</para> |
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| 168 | |
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| 169 | <warning os="z"> |
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| 170 | <para>Some kernel documentation recommends creating a symlink from |
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| 171 | <filename class="symlink">/usr/src/linux</filename> pointing to the |
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| 172 | kernel source directory. This is specific to kernels prior to the |
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[fb40919] | 173 | 2.6 series and <emphasis>must not</emphasis> be created on a CLFS |
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[3f8be484] | 174 | system as it can cause problems for packages you may wish to build |
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[fb40919] | 175 | once your base CLFS system is complete.</para> |
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[3f8be484] | 176 | |
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| 177 | <para>Also, the headers in the system's <filename |
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| 178 | class="directory">include</filename> directory should |
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| 179 | <emphasis>always</emphasis> be the ones against which Glibc was |
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[b169dfe] | 180 | compiled and should <emphasis>never</emphasis> be replaced by headers |
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| 181 | from a different kernel version.</para> |
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[3f8be484] | 182 | </warning> |
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| 183 | |
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| 184 | </sect2> |
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| 185 | |
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| 186 | <sect2 id="contents-kernel" role="content"> |
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| 187 | <title>Contents of Linux</title> |
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| 188 | |
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| 189 | <segmentedlist> |
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| 190 | <segtitle>Installed files</segtitle> |
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[61ad0b7f] | 191 | <segtitle>Installed directory</segtitle> |
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[3f8be484] | 192 | |
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| 193 | <seglistitem> |
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[3f76cac] | 194 | <seg>config-[linux-version], clfskernel-[linux-version], |
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[3f8be484] | 195 | and System.map-[linux-version]</seg> |
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[61ad0b7f] | 196 | <seg>/lib/modules</seg> |
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[3f8be484] | 197 | </seglistitem> |
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| 198 | </segmentedlist> |
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| 199 | |
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| 200 | <variablelist> |
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| 201 | <bridgehead renderas="sect3">Short Descriptions</bridgehead> |
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| 202 | <?dbfo list-presentation="list"?> |
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| 203 | <?dbhtml list-presentation="table"?> |
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| 204 | |
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| 205 | <varlistentry id="config"> |
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| 206 | <term><filename>config-[linux-version]</filename></term> |
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| 207 | <listitem> |
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| 208 | <para>Contains all the configuration selections for the kernel</para> |
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| 209 | <indexterm zone="ch-bootable-kernel config"> |
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| 210 | <primary sortas="e-/boot/config">/boot/config-[linux-version]</primary> |
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| 211 | </indexterm> |
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| 212 | </listitem> |
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| 213 | </varlistentry> |
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| 214 | |
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[3f76cac] | 215 | <varlistentry id="clfskernel"> |
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| 216 | <term><filename>clfskernel-[linux-version]</filename></term> |
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[3f8be484] | 217 | <listitem> |
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| 218 | <para>The engine of the Linux system. When turning on the |
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| 219 | computer, the kernel is the first part of the operating system |
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| 220 | that gets loaded. It detects and initializes all components of |
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| 221 | the computer's hardware, then makes these components available |
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| 222 | as a tree of files to the software and turns a single CPU into |
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| 223 | a multitasking machine capable of running scores of programs |
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| 224 | seemingly at the same time.</para> |
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[3f76cac] | 225 | <indexterm zone="ch-bootable-kernel clfskernel"> |
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| 226 | <primary sortas="b-clfskernel">clfskernel-[linux-version]</primary> |
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[3f8be484] | 227 | </indexterm> |
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| 228 | </listitem> |
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| 229 | </varlistentry> |
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| 230 | |
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| 231 | <varlistentry id="System.map"> |
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| 232 | <term><filename>System.map-[linux-version]</filename></term> |
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| 233 | <listitem> |
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| 234 | <para>A list of addresses and symbols; it maps the entry points |
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| 235 | and addresses of all the functions and data structures in the |
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| 236 | kernel</para> |
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| 237 | <indexterm zone="ch-bootable-kernel System.map"> |
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| 238 | <primary sortas="e-/boot/System.map">/boot/System.map-[linux-version]</primary> |
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| 239 | </indexterm> |
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| 240 | </listitem> |
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| 241 | </varlistentry> |
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| 242 | |
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| 243 | </variablelist> |
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| 244 | |
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| 245 | </sect2> |
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| 246 | |
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| 247 | </sect1> |
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