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Vizitor

Member

Registered: 2015-01-05

Posts: 83

[SOLVED] amd-ucode - do I need it

Hello,
I've never looked into microcode subject, because I was thinking that is somehow 'automated' when installing system.

Today I meet this subject on ArchWiki, so I checked my system and got confused.
I must say that I don't have any problem with CPU or other hardware;
- AMD FX-8370, 8 cores, Family 21, Model 2, Stepping 0
- System boots with EFISTUB (GRUB is not installed)

I checked with pacman, and I don't have installed amd-ucode.
Also:

# dmesg | grep microcode
[    1.109118] microcode: CPU0: patch_level=0x06000822
[    1.109123] microcode: CPU1: patch_level=0x06000822
[    1.109129] microcode: CPU2: patch_level=0x06000822
[    1.109136] microcode: CPU3: patch_level=0x06000822
[    1.109141] microcode: CPU4: patch_level=0x06000822
[    1.109147] microcode: CPU5: patch_level=0x06000822
[    1.109154] microcode: CPU6: patch_level=0x06000822
[    1.109160] microcode: CPU7: patch_level=0x06000822
[    1.109212] microcode: Microcode Update Driver: v2.2.
[   17.177065] microcode: CPU1: new patch_level=0x06000852
[   17.184756] microcode: CPU4: new patch_level=0x06000852
[   17.194998] microcode: CPU7: new patch_level=0x06000852
[   17.202540] microcode: CPU3: new patch_level=0x06000852
[   17.202603] x86/CPU: CPU features have changed after loading microcode, but might not take effect.

And there is /lib/firmware/amd-ucode :

$ ls -1 /lib/firmware/amd-ucode
microcode_amd.bin
microcode_amd.bin.asc
microcode_amd_fam15h.bin
microcode_amd_fam15h.bin.asc
microcode_amd_fam16h.bin
microcode_amd_fam16h.bin.asc
microcode_amd_fam17h.bin
microcode_amd_fam17h.bin.asc

So, do I need to install amd-ucode, and reconfigure system ?

Last edited by Vizitor (2019-03-04 20:15:22)

/dev/zero

Member

From: Melbourne, Australia

Registered: 2011-10-20

Posts: 1,247

Re: [SOLVED] amd-ucode - do I need it

It's hard to be sure exactly what these microcodes do because they are released from AMD in binary form.

You can see that they are distributed as part of the linux firmware project:

$ pacman -Qi amd-ucode | grep URL
URL             : http://git.kernel.org/?p=linux/kernel/git/firmware/linux-firmware.git;a=summary

If you go to the linux firmware Git repository you can find their licence:

https://git.kernel.org/pub/scm/linux/ke … .amd-ucode

Basically, people are free to distribute them in binary form, but AMD does not want to be open about the source code.

Your system may work fine without them, and no one is going to force you to use them. On the other hand, the very wiki article which you say you've read explains why you might want them. It says they are for "stability and security updates".

If you don't want those updates, it is your prerogative to not install these proprietary blobs.

loqs

Member

Registered: 2014-03-06

Posts: 19,103

Re: [SOLVED] amd-ucode - do I need it

Late loading of microcode is discouraged because certain changes can only be applied before the system has been initialized.
The update is applied to the system late and some cores seem to have not had the update applied which is another issue with late loading due to needing to stop all tasks on all cores simultaneously.
If you want the microcode to be updated early you need to install amd-ucode and follow the wiki instructions or follow https://www.kernel.org/doc/Documentatio … rocode.txt.

Vizitor

Member

Registered: 2015-01-05

Posts: 83

Re: [SOLVED] amd-ucode - do I need it

What confuses me is:
If there are amd microcodes already in /lib/firmware/amd-ucode, why do I need to install them (package amd-ucode)?
Do those (files in /lib/firmware/amd-ucode) microcodes have their functions for "stability and security updates"?

And, is this message normal:

[   17.202603] x86/CPU: CPU features have changed after loading microcode, but might not take effect.

I mean, do that take effect later when boot proccess finish; also will it dissapear if I install amd-ucode, and reconfigure system?

EDIT: loqs I saw your message AFTER I posted my. After reading Your message I finnaly understand that thing! Thank You! Now I am going to play with that!

Last edited by Vizitor (2019-03-04 20:06:56)

loqs

Member

Registered: 2014-03-06

Posts: 19,103

Re: [SOLVED] amd-ucode - do I need it

https://git.archlinux.org/svntogit/pack … rmware#n30 is where amd-ucode.img is generated from the same source as linux-firmware.
You could generate such a file locally following those commands or the second link from post #3.  Currently that is just how it is packaged.
Yes if you load the micrcode early the message will not appear.
Edit:
Ah saw your update

Last edited by loqs (2019-03-04 20:11:54)