On Wednesday 01 Feb 2017 00:55:01 Marc Joliet wrote: > On Sunday 29 January 2017 13:51:39 Mick wrote: > > Hi All, > > > > I am trying out a systemd installation on a MackBook Pro and I am not sure > > the documentation on systemd + microcode is entirely correct. So, I read > > here: > > > > https://wiki.gentoo.org/wiki/Intel_microcode#systemd > > > > that the "microcode loader is set as a module in the kernel > > configuration". > > However, my kernel configuration is not offering this option. Both 'CPU > > microcode loading support' and 'Intel microcode loading support' can only > > be set as built in elements. I am not using an initramfs (yet) so I > > wonder how I should go about this. > > AIUI these days the microcode is supposed to be put in the initramfs and > loaded from there during early boot (I read this somewhere, but don't > remember where). Dracut takes care of this, e.g., the initramfs on my > laptop contains a microcode blob: > > # lsinitrd /boot/initramfs-4.9.6-gentoo.img|grep -i micro > drwxr-xr-x 1 root root 0 Jan 27 01:14 kernel/x86/microcode > -rw-r--r-- 1 root root 983040 Jan 27 01:14 > kernel/x86/microcode/GenuineIntel.bin > > The third journal entry on said laptop is then: > > Jan 30 20:42:17 localhost kernel: microcode: microcode updated early to > revision 0x4, date = 2013-06-28 > > So it looks to me like the kernel loads it autonomously, and the reason to > put the file in the initramfs is for the microcode to get updated as early > as possible (before the kernel has to read from disk). > > HTH
I eventually got on top of this. No initramfs is needed, although if you are
using one then it will serve the same purpose too.
These are the steps I followed:
Emerged sys-apps/iucode_tool and ran:
iucode_tool -S
which spewed out the CPU signature as: 0x00040661
Then I emerged intel-microcode with USE=split-ucode, to generate the microcode
binaries the kernel can use directly. Saving and searching through the output
of the emerge compilation I found this snippet:
intel-ucode/06-46-01
signature: 0x40661 <===<
flags: 0x32
revision: 0x16
date: 2016-04-01
size: 24576
Previously in a rush, I got confused when I compared the hex notation of the
CPU signature with 0x000 in front of it, with the above. Thereafter I added
'intel-ucode/06-46-01' in the kernel, like so:
Device Drivers --->
Generic Driver Options --->
[*] Include in-kernel firmware blobs in kernel binary
(intel-ucode/06-46-01 <other_CPU_firmware_follows_here>) External firmware
blobs to build into the kernel binary
(/lib/firmware/) Firmware blobs root directory
The intel-ucode needs to be loaded early at the start of the boot process, so
I put it first and comma separated the rest of the CPU firmware blobs. I now
get an output which clearly states "microcode updated early".
I posted this in case it helps others too.
--
Regards,
Mick
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