Conversation
jarkko

Jarkko Sakkinen

Edited 1 month ago

Just wanted try out what I minimally need for qemu-system-x86_64 -kernel arch/x86/boot/bzImage: 

#!/usr/bin/env bash

set -e

make defconfig
scripts/config --set-str CONFIG_INITRAMFS_SOURCE "initramfs.txt"
yes '' | make oldconfig

cat > initramfs.txt << EOF
dir /dev 755 0 0
nod /dev/console 644 0 0 c 5 1
nod /dev/loop0 644 0 0 b 7 0
dir /bin 755 1000 1000
slink /bin/sh busybox 777 0 0
file /bin/busybox initramfs/busybox 755 0 0
dir /proc 755 0 0
dir /sys 755 0 0
dir /mnt 755 0 0
file /init initramfs/init.sh 755 0 0
EOF

mkdir initramfs

curl -sSf https://dl-cdn.alpinelinux.org/alpine/edge/main/x86_64/busybox-static-1.36.1-r25.apk | tar zx --strip-components 1
cp busybox.static initramfs/busybox

cat > initramfs/init.sh << EOF
#!/bin/sh
mount -t proc none /proc
mount -t sysfs none /sys
sh
EOF

“linux from scratch” in 32 lines :-)

#linux #kernel #alpine

3
3
2
r1w1s1@mastodon.social

Ric🐧☕

Reply to @jarkko

@jarkko nice :)

1
0
1
jarkko

Jarkko Sakkinen

Reply to @r1w1s1@mastodon.social
glad you liked it :-)
0
0
0
noflcl@mastodon.social

Stephen McNamara

Reply to @jarkko

@jarkko

I love how after decades of Linux use... This is human readable lol

Very nice

1
0
1
jarkko

Jarkko Sakkinen

Reply to @noflcl@mastodon.social

@noflcl it’s missing the last command tho: make -j$(nproc) but just a minor detail ;-)

0
0
2
jarkko

Jarkko Sakkinen

Reply to @jarkko
Edited 29 days ago
kudos to @ncopa again for the static busybox binary tip! i'll refine this at some point to multi-arch with toolchains from https://toolchains.bootlin.com/. i.e. one arg for arch and it will download the toolchain and matching busybox binary. #bootlin #buildroot
0
0
0
About social.kernel.org

Terms of service

  1. Please do not use this service in violation of the Linux Kernel Code of Conduct. Doing so will result in your account suspension with the referral of the matter to the CoC committee.

  2. "Repeating"/"boosting" someone else's status on this platform will be treated as endorsement and will fall under rule #1.

  3. You are encouraged to use this platform to promote your work on the Linux Kernel, but there is no restriction on permitted topics (with the exception of anything covered by #1 above).

  4. There is no requirement to post in English, but it should be considered the primary language of communication on this platform.

Privacy notice

The admins of this service have access to all posted statuses. They aren't looking, but if it's something they shouldn't know about, then you should not post it on this platform.

Please see the Linux Foundation Privacy Policy, which applies to this platform as well.

Getting your own account

If you would like an account on this instance, please check that the following applies to you:

  • You are listed in MAINTAINERS or CREDITS

  • OR: You have a kernel.org account or email address

  • OR: You have a long and established history of involvement with the Linux Kernel

If the above is true and you agree with the Terms of Service and Privacy Notice listed above, please use these instructions to request an account: