| 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
|---|
| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|---|
| 3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
|
|---|
| 4 | <!ENTITY % general-entities SYSTEM "../general.ent">
|
|---|
| 5 | %general-entities;
|
|---|
| 6 | ]>
|
|---|
| 7 |
|
|---|
| 8 | <sect1 id="ch-bootable-kernel" role="wrap">
|
|---|
| 9 | <?dbhtml filename="kernel.html"?>
|
|---|
| 10 |
|
|---|
| 11 | <sect1info condition="script">
|
|---|
| 12 | <productname>kernel</productname>
|
|---|
| 13 | <productnumber>&linux-version;</productnumber>
|
|---|
| 14 | <address>&linux-url;</address>
|
|---|
| 15 | </sect1info>
|
|---|
| 16 |
|
|---|
| 17 | <title>Linux-&linux-version;</title>
|
|---|
| 18 |
|
|---|
| 19 | <indexterm zone="ch-bootable-kernel">
|
|---|
| 20 | <primary sortas="a-Linux">Linux</primary>
|
|---|
| 21 | </indexterm>
|
|---|
| 22 |
|
|---|
| 23 | <sect2 role="package">
|
|---|
| 24 | <title/>
|
|---|
| 25 |
|
|---|
| 26 | <para>The Linux package contains the Linux kernel.</para>
|
|---|
| 27 |
|
|---|
| 28 | <segmentedlist>
|
|---|
| 29 | <segtitle>&buildtime;</segtitle>
|
|---|
| 30 | <segtitle>&diskspace;</segtitle>
|
|---|
| 31 |
|
|---|
| 32 | <seglistitem>
|
|---|
| 33 | <seg>&linux-knl-sbu;</seg>
|
|---|
| 34 | <seg>&linux-knl-du;</seg>
|
|---|
| 35 | </seglistitem>
|
|---|
| 36 | </segmentedlist>
|
|---|
| 37 |
|
|---|
| 38 | </sect2>
|
|---|
| 39 |
|
|---|
| 40 | <sect2 role="installation">
|
|---|
| 41 | <title>Installation of the kernel</title>
|
|---|
| 42 |
|
|---|
| 43 | <para>Building the kernel involves a few steps—configuration,
|
|---|
| 44 | compilation, and installation. Read the <filename>README</filename> file
|
|---|
| 45 | in the kernel source tree for alternative methods to the way this book
|
|---|
| 46 | configures the kernel.</para>
|
|---|
| 47 |
|
|---|
| 48 | <important>
|
|---|
| 49 | <para>
|
|---|
| 50 | Building the linux kernel for the first time is one of the most
|
|---|
| 51 | challenging tasks in LFS. Getting it right depends on the specific
|
|---|
| 52 | hardware for the target system and your specific needs. There are
|
|---|
| 53 | almost 12,000 configuration items that are available for the kernel
|
|---|
| 54 | although only about a third of them are needed for most computers. The
|
|---|
| 55 | LFS editors recommend that users not familiar with this process follow
|
|---|
| 56 | the procedures below fairly closely. The objective is to get an
|
|---|
| 57 | initial system to a point where you can log in at the command line when
|
|---|
| 58 | you reboot later in <xref linkend="ch-finish-reboot"/>. At his point
|
|---|
| 59 | optimization and customization is not a goal.
|
|---|
| 60 | </para>
|
|---|
| 61 |
|
|---|
| 62 |
|
|---|
| 63 | <para>
|
|---|
| 64 | For general information on kernel configuration see <ulink
|
|---|
| 65 | url="&hints-root;kernel-configuration.txt"/>. Additional information
|
|---|
| 66 | about configuring and building the kernel can be found at <ulink
|
|---|
| 67 | url="&anduin-sources;/kernel-nutshell/"/>.
|
|---|
| 68 | These references are a bit
|
|---|
| 69 | dated, but still give a reasonable overview of the process.
|
|---|
| 70 | </para>
|
|---|
| 71 |
|
|---|
| 72 | <para>
|
|---|
| 73 | If all else fails, you can ask for help on the <ulink
|
|---|
| 74 | url="https://www.linuxfromscratch.org/mail.html">lfs-support</ulink>
|
|---|
| 75 | mailing list. Note that subscribing is required in order for the list
|
|---|
| 76 | to avoid spam.
|
|---|
| 77 | </para>
|
|---|
| 78 | </important>
|
|---|
| 79 |
|
|---|
| 80 | <para>Prepare for compilation by running the following command:</para>
|
|---|
| 81 |
|
|---|
| 82 | <screen><userinput remap="pre">make mrproper</userinput></screen>
|
|---|
| 83 |
|
|---|
| 84 | <para>This ensures that the kernel tree is absolutely clean. The
|
|---|
| 85 | kernel team recommends that this command be issued prior to each
|
|---|
| 86 | kernel compilation. Do not rely on the source tree being clean after
|
|---|
| 87 | un-tarring.</para>
|
|---|
| 88 |
|
|---|
| 89 | <para>There are several ways to configure the kernel options. Usually,
|
|---|
| 90 | This is done through a menu-driven interface, for example:</para>
|
|---|
| 91 |
|
|---|
| 92 | <screen role="nodump"><userinput>make menuconfig</userinput></screen>
|
|---|
| 93 |
|
|---|
| 94 | <variablelist>
|
|---|
| 95 | <title>The meaning of optional make environment variables:</title>
|
|---|
| 96 |
|
|---|
| 97 | <varlistentry>
|
|---|
| 98 | <term><parameter>LANG=<host_LANG_value> LC_ALL=</parameter></term>
|
|---|
| 99 | <listitem>
|
|---|
| 100 | <para>This establishes the locale setting to the one used on the
|
|---|
| 101 | host. This may be needed for a proper menuconfig ncurses interface
|
|---|
| 102 | line drawing on a UTF-8 linux text console.</para>
|
|---|
| 103 |
|
|---|
| 104 | <para>If used, be sure to replace
|
|---|
| 105 | <replaceable><host_LANG_value></replaceable> by the value of
|
|---|
| 106 | the <envar>$LANG</envar> variable from your host. You can
|
|---|
| 107 | alternatively use instead the host's value of <envar>$LC_ALL</envar>
|
|---|
| 108 | or <envar>$LC_CTYPE</envar>.</para>
|
|---|
| 109 | </listitem>
|
|---|
| 110 | </varlistentry>
|
|---|
| 111 |
|
|---|
| 112 | <varlistentry>
|
|---|
| 113 | <term><command>make menuconfig</command></term>
|
|---|
| 114 | <listitem>
|
|---|
| 115 | <para>This launches an ncurses menu-driven interface. For other
|
|---|
| 116 | (graphical) interfaces, type <command>make help</command>.</para>
|
|---|
| 117 | </listitem>
|
|---|
| 118 | </varlistentry>
|
|---|
| 119 | </variablelist>
|
|---|
| 120 |
|
|---|
| 121 | <!-- Support for compiling a keymap into the kernel is deliberately removed -->
|
|---|
| 122 |
|
|---|
| 123 |
|
|---|
| 124 | <note>
|
|---|
| 125 | <para>A good starting place for setting up the kernel configuration is to
|
|---|
| 126 | run <command>make defconfig</command>. This will set the base
|
|---|
| 127 | configuration to a good state that takes your current system architecture
|
|---|
| 128 | into account.</para>
|
|---|
| 129 |
|
|---|
| 130 | <para>Be sure to enable/disable/set the following features or the system might
|
|---|
| 131 | not work correctly or boot at all:</para>
|
|---|
| 132 |
|
|---|
| 133 | <screen role="nodump" revision="sysv">Processor type and features --->
|
|---|
| 134 | [*] Build a relocatable kernel [CONFIG_RELOCATABLE]
|
|---|
| 135 | [*] Randomize the address of the kernel image (KASLR) [CONFIG_RANDOMIZE_BASE]
|
|---|
| 136 | General setup --->
|
|---|
| 137 | [ ] Compile the kernel with warnings as errors [CONFIG_WERROR]
|
|---|
| 138 | < > Enable kernel headers through /sys/kernel/kheaders.tar.xz [CONFIG_IKHEADERS]
|
|---|
| 139 | [ ] Configure standard kernel features (expert users) [CONFIG_EXPERT]
|
|---|
| 140 | General architecture-dependent options --->
|
|---|
| 141 | [*] Stack Protector buffer overflow detection [CONFIG_STACKPROTECTOR]
|
|---|
| 142 | [*] Strong Stack Protector [CONFIG_STACKPROTECTOR_STRONG]
|
|---|
| 143 | Device Drivers --->
|
|---|
| 144 | Firmware Drivers --->
|
|---|
| 145 | EFI (Extensible Firmware Interface) Support --->
|
|---|
| 146 | [*] Enable the generic EFI decompressor [CONFIG_EFI_ZBOOT]
|
|---|
| 147 | Graphics support --->
|
|---|
| 148 | Frame buffer Devices --->
|
|---|
| 149 | <*> Support for frame buffer devices --->
|
|---|
| 150 | Console display driver support --->
|
|---|
| 151 | [*] Framebuffer Console support [CONFIG_FRAMEBUFFER_CONSOLE]
|
|---|
| 152 | Generic Driver Options --->
|
|---|
| 153 | [ ] Support for uevent helper [CONFIG_UEVENT_HELPER]
|
|---|
| 154 | [*] Maintain a devtmpfs filesystem to mount at /dev [CONFIG_DEVTMPFS]
|
|---|
| 155 | [*] Automount devtmpfs at /dev, after the kernel mounted the rootfs [CONFIG_DEVTMPFS_MOUNT]</screen>
|
|---|
| 156 |
|
|---|
| 157 | <screen role="nodump" revision="systemd">Processor type and features --->
|
|---|
| 158 | [*] Build a relocatable kernel [CONFIG_RELOCATABLE]
|
|---|
| 159 | [*] Randomize the address of the kernel image (KASLR) [CONFIG_RANDOMIZE_BASE]
|
|---|
| 160 | General setup --->
|
|---|
| 161 | [ ] Compile the kernel with warnings as errors [CONFIG_WERROR]
|
|---|
| 162 | [ ] Auditing Support [CONFIG_AUDIT]
|
|---|
| 163 | CPU/Task time and stats accounting --->
|
|---|
| 164 | [*] Pressure stall information tracking [CONFIG_PSI]
|
|---|
| 165 | < > Enable kernel headers through /sys/kernel/kheaders.tar.xz [CONFIG_IKHEADERS]
|
|---|
| 166 | [*] Control Group support [CONFIG_CGROUPS] --->
|
|---|
| 167 | [*] Memory controller [CONFIG_MEMCG]
|
|---|
| 168 | [ ] Enable deprecated sysfs features to support old userspace tools [CONFIG_SYSFS_DEPRECATED]
|
|---|
| 169 | [ ] Configure standard kernel features (expert users) [CONFIG_EXPERT]
|
|---|
| 170 | General architecture-dependent options --->
|
|---|
| 171 | [*] Enable seccomp to safely compute untrusted bytecode [CONFIG_SECCOMP]
|
|---|
| 172 | [*] Stack Protector buffer overflow detection [CONFIG_STACKPROTECTOR]
|
|---|
| 173 | [*] Strong Stack Protector [CONFIG_STACKPROTECTOR_STRONG]
|
|---|
| 174 | Networking support --->
|
|---|
| 175 | Networking options --->
|
|---|
| 176 | <*> The IPv6 protocol [CONFIG_IPV6]
|
|---|
| 177 | Device Drivers --->
|
|---|
| 178 | Generic Driver Options --->
|
|---|
| 179 | [ ] Support for uevent helper [CONFIG_UEVENT_HELPER]
|
|---|
| 180 | [*] Maintain a devtmpfs filesystem to mount at /dev [CONFIG_DEVTMPFS]
|
|---|
| 181 | [*] Automount devtmpfs at /dev, after the kernel mounted the rootfs [CONFIG_DEVTMPFS_MOUNT]
|
|---|
| 182 | Firmware Loader --->
|
|---|
| 183 | [ ] Enable the firmware sysfs fallback mechanism [CONFIG_FW_LOADER_USER_HELPER]
|
|---|
| 184 | Firmware Drivers --->
|
|---|
| 185 | [*] Export DMI identification via sysfs to userspace [CONFIG_DMIID]
|
|---|
| 186 | EFI (Extensible Firmware Interface) Support --->
|
|---|
| 187 | [*] Enable the generic EFI decompressor [CONFIG_EFI_ZBOOT]
|
|---|
| 188 | Graphics support --->
|
|---|
| 189 | Frame buffer Devices --->
|
|---|
| 190 | <*> Support for frame buffer devices --->
|
|---|
| 191 | Console display driver support --->
|
|---|
| 192 | [*] Framebuffer Console support [CONFIG_FRAMEBUFFER_CONSOLE]
|
|---|
| 193 | File systems --->
|
|---|
| 194 | [*] Inotify support for userspace [CONFIG_INOTIFY_USER]
|
|---|
| 195 | Pseudo filesystems --->
|
|---|
| 196 | [*] Tmpfs POSIX Access Control Lists [CONFIG_TMPFS_POSIX_ACL]</screen>
|
|---|
| 197 |
|
|---|
| 198 | <para>If the partition for the LFS system is in a NVME SSD (i. e. the
|
|---|
| 199 | device node for the partition is <filename>/dev/nvme*</filename>
|
|---|
| 200 | instead of <filename>/dev/sd*</filename>), enable NVME support or
|
|---|
| 201 | the LFS system won't boot:</para>
|
|---|
| 202 |
|
|---|
| 203 | <screen role="nodump">Device Drivers --->
|
|---|
| 204 | NVME Support --->
|
|---|
| 205 | <*> NVM Express block device [CONFIG_BLK_DEV_NVME]</screen>
|
|---|
| 206 | </note>
|
|---|
| 207 |
|
|---|
| 208 | <note revision="systemd">
|
|---|
| 209 | <para>While "The IPv6 Protocol" is not strictly
|
|---|
| 210 | required, it is highly recommended by the systemd developers.</para>
|
|---|
| 211 | </note>
|
|---|
| 212 |
|
|---|
| 213 | <para>There are several other options that may be desired
|
|---|
| 214 | depending on the requirements for the system. For a list of options needed
|
|---|
| 215 | for BLFS packages, see the <ulink
|
|---|
| 216 | url="&lfs-root;blfs/view/&short-version;/longindex.html#kernel-config-index">BLFS
|
|---|
| 217 | Index of Kernel Settings</ulink>.</para>
|
|---|
| 218 |
|
|---|
| 219 | <note>
|
|---|
| 220 | <para>If your host hardware is using UEFI and you wish to boot the
|
|---|
| 221 | LFS system with it, you should adjust some kernel configuration
|
|---|
| 222 | following <ulink url="&blfs-book;postlfs/grub-setup.html#uefi-kernel">
|
|---|
| 223 | the BLFS page</ulink> <emphasis role='bold'>even if you'll use the
|
|---|
| 224 | UEFI bootloader from the host distro</emphasis>.</para>
|
|---|
| 225 | </note>
|
|---|
| 226 |
|
|---|
| 227 | <variablelist>
|
|---|
| 228 | <title>The rationale for the above configuration items:</title>
|
|---|
| 229 |
|
|---|
| 230 | <varlistentry>
|
|---|
| 231 | <term><parameter>Randomize the address of the kernel image (KASLR)</parameter></term>
|
|---|
| 232 | <listitem>
|
|---|
| 233 | <para>Enable ASLR for kernel image, to mitigate some attacks based
|
|---|
| 234 | on fixed addresses of sensitive data or code in the kernel.</para>
|
|---|
| 235 | </listitem>
|
|---|
| 236 | </varlistentry>
|
|---|
| 237 |
|
|---|
| 238 | <varlistentry>
|
|---|
| 239 | <term>
|
|---|
| 240 | <parameter>
|
|---|
| 241 | Compile the kernel with warnings as errors
|
|---|
| 242 | </parameter>
|
|---|
| 243 | </term>
|
|---|
| 244 | <listitem>
|
|---|
| 245 | <para>This may cause building failure if the compiler and/or
|
|---|
| 246 | configuration are different from those of the kernel
|
|---|
| 247 | developers.</para>
|
|---|
| 248 | </listitem>
|
|---|
| 249 | </varlistentry>
|
|---|
| 250 |
|
|---|
| 251 | <varlistentry>
|
|---|
| 252 | <term>
|
|---|
| 253 | <parameter>
|
|---|
| 254 | Enable kernel headers through /sys/kernel/kheaders.tar.xz
|
|---|
| 255 | </parameter>
|
|---|
| 256 | </term>
|
|---|
| 257 | <listitem>
|
|---|
| 258 | <para>This will require <command>cpio</command> building the kernel.
|
|---|
| 259 | <command>cpio</command> is not installed by LFS.</para>
|
|---|
| 260 | </listitem>
|
|---|
| 261 | </varlistentry>
|
|---|
| 262 |
|
|---|
| 263 | <varlistentry>
|
|---|
| 264 | <term>
|
|---|
| 265 | <parameter>
|
|---|
| 266 | Configure standard kernel features (expert users)
|
|---|
| 267 | </parameter>
|
|---|
| 268 | </term>
|
|---|
| 269 | <listitem>
|
|---|
| 270 | <para>This will make some options show up in the configuration
|
|---|
| 271 | interface but changing those options may be dangerous. Do not use
|
|---|
| 272 | this unless you know what you are doing.</para>
|
|---|
| 273 | </listitem>
|
|---|
| 274 | </varlistentry>
|
|---|
| 275 |
|
|---|
| 276 | <varlistentry>
|
|---|
| 277 | <term><parameter>Strong Stack Protector</parameter></term>
|
|---|
| 278 | <listitem>
|
|---|
| 279 | <para>Enable SSP for the kernel. We've enabled it for the entire
|
|---|
| 280 | userspace with <parameter>--enable-default-ssp</parameter>
|
|---|
| 281 | configuring GCC, but the kernel does not use GCC default setting
|
|---|
| 282 | for SSP. We enable it explicitly here.</para>
|
|---|
| 283 | </listitem>
|
|---|
| 284 | </varlistentry>
|
|---|
| 285 |
|
|---|
| 286 | <varlistentry>
|
|---|
| 287 | <term><parameter>Support for uevent helper</parameter></term>
|
|---|
| 288 | <listitem>
|
|---|
| 289 | <para>Having this option set may interfere with device
|
|---|
| 290 | management when using Udev/Eudev. </para>
|
|---|
| 291 | </listitem>
|
|---|
| 292 | </varlistentry>
|
|---|
| 293 |
|
|---|
| 294 | <varlistentry>
|
|---|
| 295 | <term><parameter>Maintain a devtmpfs</parameter></term>
|
|---|
| 296 | <listitem>
|
|---|
| 297 | <para>This will create automated device nodes which are populated by the
|
|---|
| 298 | kernel, even without Udev running. Udev then runs on top of this,
|
|---|
| 299 | managing permissions and adding symlinks. This configuration
|
|---|
| 300 | item is required for all users of Udev/Eudev.</para>
|
|---|
| 301 | </listitem>
|
|---|
| 302 | </varlistentry>
|
|---|
| 303 |
|
|---|
| 304 | <varlistentry>
|
|---|
| 305 | <term><parameter>Automount devtmpfs at /dev</parameter></term>
|
|---|
| 306 | <listitem>
|
|---|
| 307 | <para>This will mount the kernel view of the devices on /dev
|
|---|
| 308 | upon switching to root filesystem just before starting
|
|---|
| 309 | init.</para>
|
|---|
| 310 | </listitem>
|
|---|
| 311 | </varlistentry>
|
|---|
| 312 |
|
|---|
| 313 | <varlistentry>
|
|---|
| 314 | <term><parameter>Enable the generic EFI decompressor</parameter></term>
|
|---|
| 315 | <listitem>
|
|---|
| 316 | <para>Create the bootable image as an EFI application that carries
|
|---|
| 317 | the actual kernel image in compressed form. It can make the
|
|---|
| 318 | bootable image 50% smaller.</para>
|
|---|
| 319 | </listitem>
|
|---|
| 320 | </varlistentry>
|
|---|
| 321 |
|
|---|
| 322 | <varlistentry>
|
|---|
| 323 | <term><parameter>Framebuffer Console support</parameter></term>
|
|---|
| 324 | <listitem>
|
|---|
| 325 | <para>This is needed to display the Linux console on a frame
|
|---|
| 326 | buffer device. To allow the kernel to print debug messages at an
|
|---|
| 327 | early boot stage, it shouldn't be built as a kernel module
|
|---|
| 328 | unless an initramfs will be used. And, if
|
|---|
| 329 | <option>CONFIG_DRM</option> (Direct Rendering Manager) is enabled,
|
|---|
| 330 | it's likely <option>CONFIG_DRM_FBDEV_EMULATION</option> (Enable
|
|---|
| 331 | legacy fbdev support for your modesetting driver) should be
|
|---|
| 332 | enabled as well.</para>
|
|---|
| 333 | </listitem>
|
|---|
| 334 | </varlistentry>
|
|---|
| 335 |
|
|---|
| 336 | </variablelist>
|
|---|
| 337 |
|
|---|
| 338 | <para>Alternatively, <command>make oldconfig</command> may be more
|
|---|
| 339 | appropriate in some situations. See the <filename>README</filename>
|
|---|
| 340 | file for more information.</para>
|
|---|
| 341 |
|
|---|
| 342 | <para>If desired, skip kernel configuration by copying the kernel
|
|---|
| 343 | config file, <filename>.config</filename>, from the host system
|
|---|
| 344 | (assuming it is available) to the unpacked <filename
|
|---|
| 345 | class="directory">linux-&linux-version;</filename> directory. However,
|
|---|
| 346 | we do not recommend this option. It is often better to explore all the
|
|---|
| 347 | configuration menus and create the kernel configuration from
|
|---|
| 348 | scratch.</para>
|
|---|
| 349 |
|
|---|
| 350 | <para>Compile the kernel image and modules:</para>
|
|---|
| 351 |
|
|---|
| 352 | <screen><userinput remap="make">make</userinput></screen>
|
|---|
| 353 |
|
|---|
| 354 | <para>If using kernel modules, module configuration in <filename
|
|---|
| 355 | class="directory">/etc/modprobe.d</filename> may be required.
|
|---|
| 356 | Information pertaining to modules and kernel configuration is
|
|---|
| 357 | located in <xref linkend="ch-config-udev"/> and in the kernel
|
|---|
| 358 | documentation in the <filename
|
|---|
| 359 | class="directory">linux-&linux-version;/Documentation</filename> directory.
|
|---|
| 360 | Also, <filename>modprobe.d(5)</filename> may be of interest.</para>
|
|---|
| 361 |
|
|---|
| 362 | <para>Unless module support has been disabled in the kernel configuration,
|
|---|
| 363 | install the modules with:</para>
|
|---|
| 364 |
|
|---|
| 365 | <screen><userinput remap="install">make modules_install</userinput></screen>
|
|---|
| 366 |
|
|---|
| 367 | <para>After kernel compilation is complete, additional steps are
|
|---|
| 368 | required to complete the installation. Some files need to be copied to
|
|---|
| 369 | the <filename class="directory">/boot</filename> directory.</para>
|
|---|
| 370 |
|
|---|
| 371 | <caution>
|
|---|
| 372 | <para>If you've decided to use a separate &boot-dir; partition for the
|
|---|
| 373 | LFS system (maybe sharing a &boot-dir; partition with the host
|
|---|
| 374 | distro) , the files copied below should go there. The easiest way to
|
|---|
| 375 | do that is to create the entry for &boot-dir; in &fstab; first (read
|
|---|
| 376 | the previous section for details), then issue the following command
|
|---|
| 377 | as the &root; user in the
|
|---|
| 378 | <emphasis>chroot environment</emphasis>:</para>
|
|---|
| 379 |
|
|---|
| 380 | <screen role="nodump"><userinput>mount /boot</userinput></screen>
|
|---|
| 381 |
|
|---|
| 382 | <para>The path to the device node is omitted in the command because
|
|---|
| 383 | <command>mount</command> can read it from &fstab;.</para>
|
|---|
| 384 | </caution>
|
|---|
| 385 |
|
|---|
| 386 | <para>The path to the kernel image may vary depending on the platform being
|
|---|
| 387 | used. The filename below can be changed to suit your taste, but the stem of
|
|---|
| 388 | the filename should be <emphasis>vmlinuz</emphasis> to be compatible with
|
|---|
| 389 | the automatic setup of the boot process described in the next section. The
|
|---|
| 390 | following command assumes an ARM64 architecture with an EFI boot loader
|
|---|
| 391 | (for example, GRUB built in &ch-final;):</para>
|
|---|
| 392 |
|
|---|
| 393 | <screen><userinput remap="install">cp -iv arch/arm64/boot/vmlinuz.efi /boot/vmlinuz-&linux-version;-lfs-&version;</userinput></screen>
|
|---|
| 394 |
|
|---|
| 395 | <para><filename>System.map</filename> is a symbol file for the kernel.
|
|---|
| 396 | It maps the function entry points of every function in the kernel API,
|
|---|
| 397 | as well as the addresses of the kernel data structures for the running
|
|---|
| 398 | kernel. It is used as a resource when investigating kernel problems.
|
|---|
| 399 | Issue the following command to install the map file:</para>
|
|---|
| 400 |
|
|---|
| 401 | <screen><userinput remap="install">cp -iv System.map /boot/System.map-&linux-version;</userinput></screen>
|
|---|
| 402 |
|
|---|
| 403 | <para>The kernel configuration file <filename>.config</filename>
|
|---|
| 404 | produced by the <command>make menuconfig</command> step
|
|---|
| 405 | above contains all the configuration selections for the kernel
|
|---|
| 406 | that was just compiled. It is a good idea to keep this file for future
|
|---|
| 407 | reference:</para>
|
|---|
| 408 |
|
|---|
| 409 | <screen><userinput remap="install">cp -iv .config /boot/config-&linux-version;</userinput></screen>
|
|---|
| 410 |
|
|---|
| 411 | <para>Install the documentation for the Linux kernel:</para>
|
|---|
| 412 |
|
|---|
| 413 | <screen><userinput remap="install">install -d /usr/share/doc/linux-&linux-version;
|
|---|
| 414 | cp -r Documentation/* /usr/share/doc/linux-&linux-version;</userinput></screen>
|
|---|
| 415 |
|
|---|
| 416 | <para>It is important to note that the files in the kernel source
|
|---|
| 417 | directory are not owned by <emphasis>root</emphasis>. Whenever a
|
|---|
| 418 | package is unpacked as user <emphasis>root</emphasis> (like we did
|
|---|
| 419 | inside chroot), the files have the user and group IDs of whatever
|
|---|
| 420 | they were on the packager's computer. This is usually not a problem
|
|---|
| 421 | for any other package to be installed because the source tree is
|
|---|
| 422 | removed after the installation. However, the Linux source tree is
|
|---|
| 423 | often retained for a long time. Because of this, there is a chance
|
|---|
| 424 | that whatever user ID the packager used will be assigned to somebody
|
|---|
| 425 | on the machine. That person would then have write access to the kernel
|
|---|
| 426 | source.</para>
|
|---|
| 427 |
|
|---|
| 428 | <note>
|
|---|
| 429 | <para>In many cases, the configuration of the kernel will need to be
|
|---|
| 430 | updated for packages that will be installed later in BLFS. Unlike
|
|---|
| 431 | other packages, it is not necessary to remove the kernel source tree
|
|---|
| 432 | after the newly built kernel is installed.</para>
|
|---|
| 433 |
|
|---|
| 434 | <para>If the kernel source tree is going to be retained, run
|
|---|
| 435 | <command>chown -R 0:0</command> on the <filename
|
|---|
| 436 | class="directory">linux-&linux-version;</filename> directory to ensure
|
|---|
| 437 | all files are owned by user <emphasis>root</emphasis>.</para>
|
|---|
| 438 | </note>
|
|---|
| 439 |
|
|---|
| 440 | <warning>
|
|---|
| 441 | <para>Some kernel documentation recommends creating a symlink from
|
|---|
| 442 | <filename class="symlink">/usr/src/linux</filename> pointing to the kernel
|
|---|
| 443 | source directory. This is specific to kernels prior to the 2.6 series and
|
|---|
| 444 | <emphasis>must not</emphasis> be created on an LFS system as it can cause
|
|---|
| 445 | problems for packages you may wish to build once your base LFS system is
|
|---|
| 446 | complete.</para>
|
|---|
| 447 | </warning>
|
|---|
| 448 |
|
|---|
| 449 | <warning>
|
|---|
| 450 | <para>The headers in the system's <filename
|
|---|
| 451 | class="directory">include</filename> directory (<filename
|
|---|
| 452 | class="directory">/usr/include</filename>) should
|
|---|
| 453 | <emphasis>always</emphasis> be the ones against which Glibc was compiled,
|
|---|
| 454 | that is, the sanitised headers installed in <xref
|
|---|
| 455 | linkend="ch-tools-linux-headers"/>. Therefore, they should
|
|---|
| 456 | <emphasis>never</emphasis> be replaced by either the raw kernel headers
|
|---|
| 457 | or any other kernel sanitized headers.</para>
|
|---|
| 458 | </warning>
|
|---|
| 459 |
|
|---|
| 460 | </sect2>
|
|---|
| 461 |
|
|---|
| 462 | <sect2 id="conf-modprobe" role="configuration">
|
|---|
| 463 | <title>Configuring Linux Module Load Order</title>
|
|---|
| 464 |
|
|---|
| 465 | <indexterm zone="conf-modprobe">
|
|---|
| 466 | <primary sortas="e-/etc/modprobe.d/usb.conf">/etc/modprobe.d/usb.conf</primary>
|
|---|
| 467 | </indexterm>
|
|---|
| 468 |
|
|---|
| 469 | <para>Most of the time Linux modules are loaded automatically, but
|
|---|
| 470 | sometimes it needs some specific direction. The program that loads
|
|---|
| 471 | modules, <command>modprobe</command> or <command>insmod</command>, uses
|
|---|
| 472 | <filename>/etc/modprobe.d/usb.conf</filename> for this purpose. This file
|
|---|
| 473 | needs to be created so that if the USB drivers (ehci_hcd, ohci_hcd and
|
|---|
| 474 | uhci_hcd) have been built as modules, they will be loaded in the correct
|
|---|
| 475 | order; ehci_hcd needs to be loaded prior to ohci_hcd and uhci_hcd in order
|
|---|
| 476 | to avoid a warning being output at boot time.</para>
|
|---|
| 477 |
|
|---|
| 478 | <para>Create a new file <filename>/etc/modprobe.d/usb.conf</filename> by running
|
|---|
| 479 | the following:</para>
|
|---|
| 480 |
|
|---|
| 481 | <screen><userinput>install -v -m755 -d /etc/modprobe.d
|
|---|
| 482 | cat > /etc/modprobe.d/usb.conf << "EOF"
|
|---|
| 483 | <literal># Begin /etc/modprobe.d/usb.conf
|
|---|
| 484 |
|
|---|
| 485 | install ohci_hcd /sbin/modprobe ehci_hcd ; /sbin/modprobe -i ohci_hcd ; true
|
|---|
| 486 | install uhci_hcd /sbin/modprobe ehci_hcd ; /sbin/modprobe -i uhci_hcd ; true
|
|---|
| 487 |
|
|---|
| 488 | # End /etc/modprobe.d/usb.conf</literal>
|
|---|
| 489 | EOF</userinput></screen>
|
|---|
| 490 |
|
|---|
| 491 | </sect2>
|
|---|
| 492 |
|
|---|
| 493 | <sect2 id="contents-kernel" role="content">
|
|---|
| 494 | <title>Contents of Linux</title>
|
|---|
| 495 |
|
|---|
| 496 | <segmentedlist>
|
|---|
| 497 | <segtitle>Installed files</segtitle>
|
|---|
| 498 | <segtitle>Installed directories</segtitle>
|
|---|
| 499 |
|
|---|
| 500 | <seglistitem>
|
|---|
| 501 | <seg>config-&linux-version;,
|
|---|
| 502 | vmlinuz-&linux-version;-lfs-&version;,
|
|---|
| 503 | and System.map-&linux-version;</seg>
|
|---|
| 504 | <seg>/lib/modules, /usr/share/doc/linux-&linux-version;</seg>
|
|---|
| 505 | </seglistitem>
|
|---|
| 506 | </segmentedlist>
|
|---|
| 507 |
|
|---|
| 508 | <variablelist>
|
|---|
| 509 | <bridgehead renderas="sect3">Short Descriptions</bridgehead>
|
|---|
| 510 | <?dbfo list-presentation="list"?>
|
|---|
| 511 | <?dbhtml list-presentation="table"?>
|
|---|
| 512 |
|
|---|
| 513 | <varlistentry id="config">
|
|---|
| 514 | <term><filename>config-&linux-version;</filename></term>
|
|---|
| 515 | <listitem>
|
|---|
| 516 | <para>Contains all the configuration selections for the kernel</para>
|
|---|
| 517 | <indexterm zone="ch-bootable-kernel config">
|
|---|
| 518 | <primary sortas="e-/boot/config">/boot/config-&linux-version;</primary>
|
|---|
| 519 | </indexterm>
|
|---|
| 520 | </listitem>
|
|---|
| 521 | </varlistentry>
|
|---|
| 522 |
|
|---|
| 523 | <varlistentry id="lfskernel">
|
|---|
| 524 | <term><filename>vmlinuz-&linux-version;-lfs-&version;</filename></term>
|
|---|
| 525 | <listitem>
|
|---|
| 526 | <para>The engine of the Linux system. When turning on the computer,
|
|---|
| 527 | the kernel is the first part of the operating system that gets loaded.
|
|---|
| 528 | It detects and initializes all components of the computer's hardware,
|
|---|
| 529 | then makes these components available as a tree of files to the
|
|---|
| 530 | software and turns a single CPU into a multitasking machine capable
|
|---|
| 531 | of running scores of programs seemingly at the same time</para>
|
|---|
| 532 | <indexterm zone="ch-bootable-kernel lfskernel">
|
|---|
| 533 | <primary sortas="b-lfskernel">lfskernel-&linux-version;</primary>
|
|---|
| 534 | </indexterm>
|
|---|
| 535 | </listitem>
|
|---|
| 536 | </varlistentry>
|
|---|
| 537 |
|
|---|
| 538 | <varlistentry id="System.map">
|
|---|
| 539 | <term><filename>System.map-&linux-version;</filename></term>
|
|---|
| 540 | <listitem>
|
|---|
| 541 | <para>A list of addresses and symbols; it maps the entry points and
|
|---|
| 542 | addresses of all the functions and data structures in the
|
|---|
| 543 | kernel</para>
|
|---|
| 544 | <indexterm zone="ch-bootable-kernel System.map">
|
|---|
| 545 | <primary sortas="e-/boot/System.map">/boot/System.map-&linux-version;</primary>
|
|---|
| 546 | </indexterm>
|
|---|
| 547 | </listitem>
|
|---|
| 548 | </varlistentry>
|
|---|
| 549 |
|
|---|
| 550 | </variablelist>
|
|---|
| 551 |
|
|---|
| 552 | </sect2>
|
|---|
| 553 |
|
|---|
| 554 | </sect1>
|
|---|
