How-To::Apply Intel-Microcode on Salix/Slackware

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pedro37
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Joined: 21. Dec 2020, 21:15

How-To::Apply Intel-Microcode on Salix/Slackware

Post by pedro37 » 28. Dec 2020, 23:11

I am not going to talk about the specter/meltdown bugs as i thing is well explained across the internet.

This how to shows how i installed the iucode_tool and intel-microcode packages on my machine.

First thing first: you can download the specter-meltdown-checker script to see if your processor is affected from:

"https://github.com/speed47/spectre-meltdown-checker".

After unpacking the script you run:

# ./specter-meltdown-checker.sh --explain

If your processor is vulnerable you should see some red warnings that say VULNERABLE.


Now to the procedure:

1- You need the packages iucode_tool and intel-microcode. You can install from spi, slapt-src or even compile from the site slackbuilds.org

2 - After compiling and installing there should be an archive named intel-ucode.cpio in the /boot directory. This archive will be concatenated with an initrd that you will create.

3 - Create the initrd:

# usr/share/mkinitrd/mkinitrd_command_generator.sh -i (-i interactive)

4 - Run the sugested command, but change the "-o /boot/initrd.gz" to "-o /boot/initrd-version-of-your-kernel.gz"

ex: -o /boot/initrd-4.4.240.gz"

5 - Having created the initrd-version-of-your-kernel, we are going to rename it so that we can concatenate the intel-ucode.cpio:

# cd /boot
# mv -v initrd-4.4.240.gz initrd-4.4.240.old.gz
# cat /boot/intel-ucode.cpio /boot/initrd-4.4.240.old.gz > /boot/initrd-4.4.240.gz

6 - After that you can remove the old initrd and create a new one:

# rm -fv initrd-4.4.240.old.gz initrd.gz
# ln -sv initrd-4.4.240.gz initrd.gz

7 - update the bootloader (lilo/elilo/grub)

# lilo -v
or
# grub-mkconfig -o /boot/grub/grub.cfg

8 - Reboot the machine. You can run again the specter-meltdow-checker to confirm:

# ./specter-meltdow-checker.sh --explain | grep 'NOT VULNERABLE'

Done!!

If you upgrade the kernel, you have to recreate the initrd and concatenate the archive again!

Hope someone find this helpful and useful.
Cheers!!

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