1 | <?xml version="1.0" encoding="UTF-8"?>
|
---|
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="initramfs">
|
---|
9 | <?dbhtml filename="initramfs.html"?>
|
---|
10 |
|
---|
11 |
|
---|
12 | <title>About initramfs</title>
|
---|
13 |
|
---|
14 | <para>
|
---|
15 | The only purpose of an initramfs is to mount the root filesystem. The
|
---|
16 | initramfs is a complete set of directories that you would find on a normal
|
---|
17 | root filesystem. It is bundled into a single cpio archive and compressed
|
---|
18 | with one of several compression algorithms.
|
---|
19 | </para>
|
---|
20 |
|
---|
21 | <para>
|
---|
22 | At boot time, the boot loader loads the kernel and the initramfs image
|
---|
23 | into memory and starts the kernel. The kernel checks for the presence
|
---|
24 | of the initramfs and, if found, mounts it as / and runs /init. The init
|
---|
25 | program is typically a shell script. Note that the boot process takes
|
---|
26 | longer, possibly significantly longer, if an initramfs is used.
|
---|
27 | </para>
|
---|
28 |
|
---|
29 | <para>
|
---|
30 | For most distributions, kernel modules are the biggest reason to have
|
---|
31 | an initramfs. In a general distribution, there are many unknowns such
|
---|
32 | as file system types and disk layouts. In a way, this is the opposite
|
---|
33 | of LFS where the system capabilities and layout are known and a custom
|
---|
34 | kernel is normally built. In this situation, an initramfs is rarely
|
---|
35 | needed.
|
---|
36 | </para>
|
---|
37 |
|
---|
38 | <para>
|
---|
39 | There are only four primary reasons to have an initramfs in the LFS
|
---|
40 | environment: loading the rootfs from a network, loading it from an LVM
|
---|
41 | logical volume, having an encrypted rootfs where a password is required, or
|
---|
42 | for the convenience of specifying the rootfs as a LABEL or UUID. Anything
|
---|
43 | else usually means that the kernel was not configured properly.
|
---|
44 | </para>
|
---|
45 |
|
---|
46 | <sect2 id="initramfs-build">
|
---|
47 | <title>Building an initramfs</title>
|
---|
48 |
|
---|
49 | <para>
|
---|
50 | If you do decide to build an initramfs, the following scripts will
|
---|
51 | provide a basis to do it. The scripts will allow specifying a rootfs
|
---|
52 | via partition UUID or partition LABEL or a rootfs on an LVM logical
|
---|
53 | volume. They do not support an encrypted root file system or mounting
|
---|
54 | the rootfs over a network card. For a more complete capability see
|
---|
55 | <ulink url="https://www.linuxfromscratch.org/hints/read.html"> the LFS
|
---|
56 | Hints</ulink> or <ulink
|
---|
57 | url="https://fedoraproject.org/wiki/Dracut">dracut</ulink>.
|
---|
58 | </para>
|
---|
59 |
|
---|
60 | <para>
|
---|
61 | To install these scripts, run the following commands as the
|
---|
62 | <systemitem class="username">root</systemitem> user:
|
---|
63 | </para>
|
---|
64 |
|
---|
65 | <screen role="root"><userinput>cat > /usr/sbin/mkinitramfs << "EOF"
|
---|
66 | <literal>#!/bin/bash
|
---|
67 | # This file based in part on the mkinitramfs script for the LFS LiveCD
|
---|
68 | # written by Alexander E. Patrakov and Jeremy Huntwork.
|
---|
69 |
|
---|
70 | copy()
|
---|
71 | {
|
---|
72 | local file
|
---|
73 |
|
---|
74 | if [ "$2" = "lib" ]; then
|
---|
75 | file=$(PATH=/usr/lib type -p $1)
|
---|
76 | else
|
---|
77 | file=$(type -p $1)
|
---|
78 | fi
|
---|
79 |
|
---|
80 | if [ -n "$file" ] ; then
|
---|
81 | cp $file $WDIR/usr/$2
|
---|
82 | else
|
---|
83 | echo "Missing required file: $1 for directory $2"
|
---|
84 | rm -rf $WDIR
|
---|
85 | exit 1
|
---|
86 | fi
|
---|
87 | }
|
---|
88 |
|
---|
89 | if [ -z $1 ] ; then
|
---|
90 | INITRAMFS_FILE=initrd.img-no-kmods
|
---|
91 | else
|
---|
92 | KERNEL_VERSION=$1
|
---|
93 | INITRAMFS_FILE=initrd.img-$KERNEL_VERSION
|
---|
94 | fi
|
---|
95 |
|
---|
96 | if [ -n "$KERNEL_VERSION" ] && [ ! -d "/usr/lib/modules/$1" ] ; then
|
---|
97 | echo "No modules directory named $1"
|
---|
98 | exit 1
|
---|
99 | fi
|
---|
100 |
|
---|
101 | printf "Creating $INITRAMFS_FILE... "
|
---|
102 |
|
---|
103 | binfiles="sh cat cp dd killall ls mkdir mknod mount "
|
---|
104 | binfiles="$binfiles umount sed sleep ln rm uname"
|
---|
105 | binfiles="$binfiles readlink basename"
|
---|
106 |
|
---|
107 | # Systemd installs udevadm in /bin. Other udev implementations have it in /sbin
|
---|
108 | if [ -x /usr/bin/udevadm ] ; then binfiles="$binfiles udevadm"; fi
|
---|
109 |
|
---|
110 | sbinfiles="modprobe blkid switch_root"
|
---|
111 |
|
---|
112 | # Optional files and locations
|
---|
113 | for f in mdadm mdmon udevd udevadm; do
|
---|
114 | if [ -x /usr/sbin/$f ] ; then sbinfiles="$sbinfiles $f"; fi
|
---|
115 | done
|
---|
116 |
|
---|
117 | # Add lvm if present (cannot be done with the others because it
|
---|
118 | # also needs dmsetup
|
---|
119 | if [ -x /usr/sbin/lvm ] ; then sbinfiles="$sbinfiles lvm dmsetup"; fi
|
---|
120 |
|
---|
121 | unsorted=$(mktemp /tmp/unsorted.XXXXXXXXXX)
|
---|
122 |
|
---|
123 | DATADIR=/usr/share/mkinitramfs
|
---|
124 | INITIN=init.in
|
---|
125 |
|
---|
126 | # Create a temporary working directory
|
---|
127 | WDIR=$(mktemp -d /tmp/initrd-work.XXXXXXXXXX)
|
---|
128 |
|
---|
129 | # Create base directory structure
|
---|
130 | mkdir -p $WDIR/{dev,run,sys,proc,usr/{bin,lib/{firmware,modules},sbin}}
|
---|
131 | mkdir -p $WDIR/etc/{modprobe.d,udev/rules.d}
|
---|
132 | touch $WDIR/etc/modprobe.d/modprobe.conf
|
---|
133 | ln -s usr/bin $WDIR/bin
|
---|
134 | ln -s usr/lib $WDIR/lib
|
---|
135 | ln -s usr/sbin $WDIR/sbin
|
---|
136 | ln -s lib $WDIR/lib64
|
---|
137 |
|
---|
138 | # Create necessary device nodes
|
---|
139 | mknod -m 640 $WDIR/dev/console c 5 1
|
---|
140 | mknod -m 664 $WDIR/dev/null c 1 3
|
---|
141 |
|
---|
142 | # Install the udev configuration files
|
---|
143 | if [ -f /etc/udev/udev.conf ]; then
|
---|
144 | cp /etc/udev/udev.conf $WDIR/etc/udev/udev.conf
|
---|
145 | fi
|
---|
146 |
|
---|
147 | for file in $(find /etc/udev/rules.d/ -type f) ; do
|
---|
148 | cp $file $WDIR/etc/udev/rules.d
|
---|
149 | done
|
---|
150 |
|
---|
151 | # Install any firmware present
|
---|
152 | cp -a /usr/lib/firmware $WDIR/usr/lib
|
---|
153 |
|
---|
154 | # Copy the RAID configuration file if present
|
---|
155 | if [ -f /etc/mdadm.conf ] ; then
|
---|
156 | cp /etc/mdadm.conf $WDIR/etc
|
---|
157 | fi
|
---|
158 |
|
---|
159 | # Install the init file
|
---|
160 | install -m0755 $DATADIR/$INITIN $WDIR/init
|
---|
161 |
|
---|
162 | if [ -n "$KERNEL_VERSION" ] ; then
|
---|
163 | if [ -x /usr/bin/kmod ] ; then
|
---|
164 | binfiles="$binfiles kmod"
|
---|
165 | else
|
---|
166 | binfiles="$binfiles lsmod"
|
---|
167 | sbinfiles="$sbinfiles insmod"
|
---|
168 | fi
|
---|
169 | fi
|
---|
170 |
|
---|
171 | # Install basic binaries
|
---|
172 | for f in $binfiles ; do
|
---|
173 | ldd /usr/bin/$f | sed "s/\t//" | cut -d " " -f1 >> $unsorted
|
---|
174 | copy /usr/bin/$f bin
|
---|
175 | done
|
---|
176 |
|
---|
177 | for f in $sbinfiles ; do
|
---|
178 | ldd /usr/sbin/$f | sed "s/\t//" | cut -d " " -f1 >> $unsorted
|
---|
179 | copy $f sbin
|
---|
180 | done
|
---|
181 |
|
---|
182 | # Add udevd libraries if not in /usr/sbin
|
---|
183 | if [ -x /usr/lib/udev/udevd ] ; then
|
---|
184 | ldd /usr/lib/udev/udevd | sed "s/\t//" | cut -d " " -f1 >> $unsorted
|
---|
185 | elif [ -x /usr/lib/systemd/systemd-udevd ] ; then
|
---|
186 | ldd /usr/lib/systemd/systemd-udevd | sed "s/\t//" | cut -d " " -f1 >> $unsorted
|
---|
187 | fi
|
---|
188 |
|
---|
189 | # Add module symlinks if appropriate
|
---|
190 | if [ -n "$KERNEL_VERSION" ] && [ -x /usr/bin/kmod ] ; then
|
---|
191 | ln -s kmod $WDIR/usr/bin/lsmod
|
---|
192 | ln -s kmod $WDIR/usr/bin/insmod
|
---|
193 | fi
|
---|
194 |
|
---|
195 | # Add lvm symlinks if appropriate
|
---|
196 | # Also copy the lvm.conf file
|
---|
197 | if [ -x /usr/sbin/lvm ] ; then
|
---|
198 | ln -s lvm $WDIR/usr/sbin/lvchange
|
---|
199 | ln -s lvm $WDIR/usr/sbin/lvrename
|
---|
200 | ln -s lvm $WDIR/usr/sbin/lvextend
|
---|
201 | ln -s lvm $WDIR/usr/sbin/lvcreate
|
---|
202 | ln -s lvm $WDIR/usr/sbin/lvdisplay
|
---|
203 | ln -s lvm $WDIR/usr/sbin/lvscan
|
---|
204 |
|
---|
205 | ln -s lvm $WDIR/usr/sbin/pvchange
|
---|
206 | ln -s lvm $WDIR/usr/sbin/pvck
|
---|
207 | ln -s lvm $WDIR/usr/sbin/pvcreate
|
---|
208 | ln -s lvm $WDIR/usr/sbin/pvdisplay
|
---|
209 | ln -s lvm $WDIR/usr/sbin/pvscan
|
---|
210 |
|
---|
211 | ln -s lvm $WDIR/usr/sbin/vgchange
|
---|
212 | ln -s lvm $WDIR/usr/sbin/vgcreate
|
---|
213 | ln -s lvm $WDIR/usr/sbin/vgscan
|
---|
214 | ln -s lvm $WDIR/usr/sbin/vgrename
|
---|
215 | ln -s lvm $WDIR/usr/sbin/vgck
|
---|
216 | # Conf file(s)
|
---|
217 | cp -a /etc/lvm $WDIR/etc
|
---|
218 | fi
|
---|
219 |
|
---|
220 | # Install libraries
|
---|
221 | sort $unsorted | uniq | while read library ; do
|
---|
222 | # linux-vdso and linux-gate are pseudo libraries and do not correspond to a file
|
---|
223 | # libsystemd-shared is in /lib/systemd, so it is not found by copy, and
|
---|
224 | # it is copied below anyway
|
---|
225 | if [[ "$library" == linux-vdso.so.1 ]] ||
|
---|
226 | [[ "$library" == linux-gate.so.1 ]] ||
|
---|
227 | [[ "$library" == libsystemd-shared* ]]; then
|
---|
228 | continue
|
---|
229 | fi
|
---|
230 |
|
---|
231 | copy $library lib
|
---|
232 | done
|
---|
233 |
|
---|
234 | if [ -d /usr/lib/udev ]; then
|
---|
235 | cp -a /usr/lib/udev $WDIR/usr/lib
|
---|
236 | fi
|
---|
237 | if [ -d /usr/lib/systemd ]; then
|
---|
238 | cp -a /usr/lib/systemd $WDIR/usr/lib
|
---|
239 | fi
|
---|
240 | if [ -d /usr/lib/elogind ]; then
|
---|
241 | cp -a /usr/lib/elogind $WDIR/usr/lib
|
---|
242 | fi
|
---|
243 |
|
---|
244 | # Install the kernel modules if requested
|
---|
245 | if [ -n "$KERNEL_VERSION" ]; then
|
---|
246 | find \
|
---|
247 | /usr/lib/modules/$KERNEL_VERSION/kernel/{crypto,fs,lib} \
|
---|
248 | /usr/lib/modules/$KERNEL_VERSION/kernel/drivers/{block,ata,nvme,md,firewire} \
|
---|
249 | /usr/lib/modules/$KERNEL_VERSION/kernel/drivers/{scsi,message,pcmcia,virtio} \
|
---|
250 | /usr/lib/modules/$KERNEL_VERSION/kernel/drivers/usb/{host,storage} \
|
---|
251 | -type f 2> /dev/null | cpio --make-directories -p --quiet $WDIR
|
---|
252 |
|
---|
253 | cp /usr/lib/modules/$KERNEL_VERSION/modules.{builtin,order} \
|
---|
254 | $WDIR/usr/lib/modules/$KERNEL_VERSION
|
---|
255 | if [ -f /usr/lib/modules/$KERNEL_VERSION/modules.builtin.modinfo ]; then
|
---|
256 | cp /usr/lib/modules/$KERNEL_VERSION/modules.builtin.modinfo \
|
---|
257 | $WDIR/usr/lib/modules/$KERNEL_VERSION
|
---|
258 | fi
|
---|
259 |
|
---|
260 | depmod -b $WDIR $KERNEL_VERSION
|
---|
261 | fi
|
---|
262 |
|
---|
263 | ( cd $WDIR ; find . | cpio -o -H newc --quiet | gzip -9 ) > $INITRAMFS_FILE
|
---|
264 |
|
---|
265 | # Prepare early loading of microcode if available
|
---|
266 | if ls /usr/lib/firmware/intel-ucode/* >/dev/null 2>&1 ||
|
---|
267 | ls /usr/lib/firmware/amd-ucode/* >/dev/null 2>&1; then
|
---|
268 |
|
---|
269 | # first empty WDIR to reuse it
|
---|
270 | rm -r $WDIR/*
|
---|
271 |
|
---|
272 | DSTDIR=$WDIR/kernel/x86/microcode
|
---|
273 | mkdir -p $DSTDIR
|
---|
274 |
|
---|
275 | if [ -d /usr/lib/firmware/amd-ucode ]; then
|
---|
276 | cat /usr/lib/firmware/amd-ucode/microcode_amd*.bin > $DSTDIR/AuthenticAMD.bin
|
---|
277 | fi
|
---|
278 |
|
---|
279 | if [ -d /usr/lib/firmware/intel-ucode ]; then
|
---|
280 | cat /usr/lib/firmware/intel-ucode/* > $DSTDIR/GenuineIntel.bin
|
---|
281 | fi
|
---|
282 |
|
---|
283 | ( cd $WDIR; find . | cpio -o -H newc --quiet ) > microcode.img
|
---|
284 | cat microcode.img $INITRAMFS_FILE > tmpfile
|
---|
285 | mv tmpfile $INITRAMFS_FILE
|
---|
286 | rm microcode.img
|
---|
287 | fi
|
---|
288 |
|
---|
289 | # Remove the temporary directories and files
|
---|
290 | rm -rf $WDIR $unsorted
|
---|
291 | printf "done.\n"
|
---|
292 | </literal>
|
---|
293 | EOF
|
---|
294 |
|
---|
295 | chmod 0755 /usr/sbin/mkinitramfs</userinput></screen>
|
---|
296 |
|
---|
297 | <screen role="root"><userinput>mkdir -p /usr/share/mkinitramfs &&
|
---|
298 | cat > /usr/share/mkinitramfs/init.in << "EOF"
|
---|
299 | <literal>#!/bin/sh
|
---|
300 |
|
---|
301 | PATH=/usr/bin:/usr/sbin
|
---|
302 | export PATH
|
---|
303 |
|
---|
304 | problem()
|
---|
305 | {
|
---|
306 | printf "Encountered a problem!\n\nDropping you to a shell.\n\n"
|
---|
307 | sh
|
---|
308 | }
|
---|
309 |
|
---|
310 | no_device()
|
---|
311 | {
|
---|
312 | printf "The device %s, which is supposed to contain the\n" $1
|
---|
313 | printf "root file system, does not exist.\n"
|
---|
314 | printf "Please fix this problem and exit this shell.\n\n"
|
---|
315 | }
|
---|
316 |
|
---|
317 | no_mount()
|
---|
318 | {
|
---|
319 | printf "Could not mount device %s\n" $1
|
---|
320 | printf "Sleeping forever. Please reboot and fix the kernel command line.\n\n"
|
---|
321 | printf "Maybe the device is formatted with an unsupported file system?\n\n"
|
---|
322 | printf "Or maybe filesystem type autodetection went wrong, in which case\n"
|
---|
323 | printf "you should add the rootfstype=... parameter to the kernel command line.\n\n"
|
---|
324 | printf "Available partitions:\n"
|
---|
325 | }
|
---|
326 |
|
---|
327 | do_mount_root()
|
---|
328 | {
|
---|
329 | mkdir /.root
|
---|
330 | [ -n "$rootflags" ] && rootflags="$rootflags,"
|
---|
331 | rootflags="$rootflags$ro"
|
---|
332 |
|
---|
333 | case "$root" in
|
---|
334 | /dev/* ) device=$root ;;
|
---|
335 | UUID=* ) eval $root; device="/dev/disk/by-uuid/$UUID" ;;
|
---|
336 | PARTUUID=*) eval $root; device="/dev/disk/by-partuuid/$PARTUUID" ;;
|
---|
337 | LABEL=* ) eval $root; device="/dev/disk/by-label/$LABEL" ;;
|
---|
338 | "" ) echo "No root device specified." ; problem ;;
|
---|
339 | esac
|
---|
340 |
|
---|
341 | while [ ! -b "$device" ] ; do
|
---|
342 | no_device $device
|
---|
343 | problem
|
---|
344 | done
|
---|
345 |
|
---|
346 | if ! mount -n -t "$rootfstype" -o "$rootflags" "$device" /.root ; then
|
---|
347 | no_mount $device
|
---|
348 | cat /proc/partitions
|
---|
349 | while true ; do sleep 10000 ; done
|
---|
350 | else
|
---|
351 | echo "Successfully mounted device $root"
|
---|
352 | fi
|
---|
353 | }
|
---|
354 |
|
---|
355 | do_try_resume()
|
---|
356 | {
|
---|
357 | case "$resume" in
|
---|
358 | UUID=* ) eval $resume; resume="/dev/disk/by-uuid/$UUID" ;;
|
---|
359 | LABEL=*) eval $resume; resume="/dev/disk/by-label/$LABEL" ;;
|
---|
360 | esac
|
---|
361 |
|
---|
362 | if $noresume || ! [ -b "$resume" ]; then return; fi
|
---|
363 |
|
---|
364 | ls -lH "$resume" | ( read x x x x maj min x
|
---|
365 | echo -n ${maj%,}:$min > /sys/power/resume )
|
---|
366 | }
|
---|
367 |
|
---|
368 | init=/sbin/init
|
---|
369 | root=
|
---|
370 | rootdelay=
|
---|
371 | rootfstype=auto
|
---|
372 | ro="ro"
|
---|
373 | rootflags=
|
---|
374 | device=
|
---|
375 | resume=
|
---|
376 | noresume=false
|
---|
377 |
|
---|
378 | mount -n -t devtmpfs devtmpfs /dev
|
---|
379 | mount -n -t proc proc /proc
|
---|
380 | mount -n -t sysfs sysfs /sys
|
---|
381 | mount -n -t tmpfs tmpfs /run
|
---|
382 |
|
---|
383 | read -r cmdline < /proc/cmdline
|
---|
384 |
|
---|
385 | for param in $cmdline ; do
|
---|
386 | case $param in
|
---|
387 | init=* ) init=${param#init=} ;;
|
---|
388 | root=* ) root=${param#root=} ;;
|
---|
389 | rootdelay=* ) rootdelay=${param#rootdelay=} ;;
|
---|
390 | rootfstype=*) rootfstype=${param#rootfstype=} ;;
|
---|
391 | rootflags=* ) rootflags=${param#rootflags=} ;;
|
---|
392 | resume=* ) resume=${param#resume=} ;;
|
---|
393 | noresume ) noresume=true ;;
|
---|
394 | ro ) ro="ro" ;;
|
---|
395 | rw ) ro="rw" ;;
|
---|
396 | esac
|
---|
397 | done
|
---|
398 |
|
---|
399 | # udevd location depends on version
|
---|
400 | if [ -x /sbin/udevd ]; then
|
---|
401 | UDEVD=/sbin/udevd
|
---|
402 | elif [ -x /lib/udev/udevd ]; then
|
---|
403 | UDEVD=/lib/udev/udevd
|
---|
404 | elif [ -x /lib/systemd/systemd-udevd ]; then
|
---|
405 | UDEVD=/lib/systemd/systemd-udevd
|
---|
406 | else
|
---|
407 | echo "Cannot find udevd nor systemd-udevd"
|
---|
408 | problem
|
---|
409 | fi
|
---|
410 |
|
---|
411 | ${UDEVD} --daemon --resolve-names=never
|
---|
412 | udevadm trigger
|
---|
413 | udevadm settle
|
---|
414 |
|
---|
415 | if [ -f /etc/mdadm.conf ] ; then mdadm -As ; fi
|
---|
416 | if [ -x /sbin/vgchange ] ; then /sbin/vgchange -a y > /dev/null ; fi
|
---|
417 | if [ -n "$rootdelay" ] ; then sleep "$rootdelay" ; fi
|
---|
418 |
|
---|
419 | do_try_resume # This function will not return if resuming from disk
|
---|
420 | do_mount_root
|
---|
421 |
|
---|
422 | killall -w ${UDEVD##*/}
|
---|
423 |
|
---|
424 | exec switch_root /.root "$init" "$@"
|
---|
425 | </literal>
|
---|
426 | EOF</userinput></screen>
|
---|
427 |
|
---|
428 | </sect2>
|
---|
429 |
|
---|
430 | <sect2 id="initramfs-install">
|
---|
431 | <title>Using an initramfs</title>
|
---|
432 |
|
---|
433 | <bridgehead renderas="sect3">Required Runtime Dependency</bridgehead>
|
---|
434 |
|
---|
435 | <para role="required">
|
---|
436 | <xref role="runtime" linkend="cpio"/>
|
---|
437 | </para>
|
---|
438 |
|
---|
439 | <bridgehead renderas="sect3">Other Runtime Dependencies</bridgehead>
|
---|
440 |
|
---|
441 | <para role="optional">
|
---|
442 | <xref role="runtime" linkend="lvm2"/> and/or
|
---|
443 | <xref role="runtime" linkend="mdadm"/> must be installed before
|
---|
444 | generating the initramfs, if the system partition uses them.
|
---|
445 | </para>
|
---|
446 |
|
---|
447 |
|
---|
448 |
|
---|
449 | <para>
|
---|
450 | To build an initramfs, run the following as the <systemitem
|
---|
451 | class="username">root</systemitem> user:
|
---|
452 | </para>
|
---|
453 |
|
---|
454 | <screen role="nodump"><userinput>mkinitramfs [KERNEL VERSION]</userinput></screen>
|
---|
455 |
|
---|
456 | <para>
|
---|
457 | The optional argument is the directory where the appropriate kernel
|
---|
458 | modules are located. This must be a subdirectory of <filename
|
---|
459 | class='directory'> /lib/modules</filename>. If no modules are specified,
|
---|
460 | then the initramfs is named <emphasis>initrd.img-no-kmods</emphasis>.
|
---|
461 | If a kernel version is specified, the initrd is named
|
---|
462 | <emphasis>initrd.img-$KERNEL_VERSION</emphasis> and is only appropriate
|
---|
463 | for the specific kernel specified. The output file will be placed in the
|
---|
464 | current directory.
|
---|
465 | </para>
|
---|
466 |
|
---|
467 | <para>
|
---|
468 | If early loading of microcode is needed (see <xref
|
---|
469 | linkend="cpu-microcode"/>), you can install the appropriate blob or
|
---|
470 | container in <filename class="directory">/lib/firmware</filename>.
|
---|
471 | It will be automatically added to the initrd when running
|
---|
472 | <command>mkinitramfs</command>.
|
---|
473 | </para>
|
---|
474 |
|
---|
475 | <para>
|
---|
476 | After generating the initrd, copy it to the <filename
|
---|
477 | class='directory'>/boot</filename> directory.
|
---|
478 | </para>
|
---|
479 |
|
---|
480 | <para>
|
---|
481 | Now edit <filename>/boot/grub/grub.cfg</filename> and add a new
|
---|
482 | menuentry. Below are several examples.
|
---|
483 | </para>
|
---|
484 |
|
---|
485 | <screen role="nodump"><userinput># Generic initramfs and root fs identified by UUID
|
---|
486 | menuentry "LFS Dev (LFS-7.0-Feb14) initrd, Linux 3.0.4"
|
---|
487 | {
|
---|
488 | linux /vmlinuz-3.0.4-lfs-20120214 root=UUID=54b934a9-302d-415e-ac11-4988408eb0a8 ro
|
---|
489 | initrd /initrd.img-no-kmods
|
---|
490 | }</userinput></screen>
|
---|
491 |
|
---|
492 | <screen role="nodump"><userinput># Generic initramfs and root fs on LVM partition
|
---|
493 | menuentry "LFS Dev (LFS-7.0-Feb18) initrd lvm, Linux 3.0.4"
|
---|
494 | {
|
---|
495 | linux /vmlinuz-3.0.4-lfs-20120218 root=/dev/mapper/myroot ro
|
---|
496 | initrd /initrd.img-no-kmods
|
---|
497 | }</userinput></screen>
|
---|
498 |
|
---|
499 | <screen role="nodump"><userinput># Specific initramfs and root fs identified by LABEL
|
---|
500 | menuentry "LFS Dev (LFS-7.1-Feb20) initrd label, Linux 3.2.6"
|
---|
501 | {
|
---|
502 | linux /vmlinuz-3.2.6-lfs71-120220 root=LABEL=lfs71 ro
|
---|
503 | initrd /initrd.img-3.2.6-lfs71-120220
|
---|
504 | }</userinput></screen>
|
---|
505 |
|
---|
506 | <para>
|
---|
507 | Finally, reboot the system and select the desired system.
|
---|
508 | </para>
|
---|
509 |
|
---|
510 | </sect2>
|
---|
511 |
|
---|
512 | </sect1>
|
---|