Add support for microcode update on newer AMD CPUs (10h+)

[avg]

Summary

This includes new code for parsing microcode files as well as
the kernel-side change to apply the update on all processors
at the same time.

Developed with help from Borislav Petkov, formerly [e-mail].

Test Plan

Tested using Athlon II X2 processor on a system where BIOS does
not have the latest microcode version:
/boot/firmware/microcode_amd.bin: updating cpu /dev/cpuctl0 to revision 0x10000c7... done.

The microcode file is taken from here:
https://web.archive.org/web/20160528230514/http://www.amd64.org/microcode.html
(note that the site seems to be down at the moment)
It can also be found here:
https://git.kernel.org/cgit/linux/kernel/git/firmware/linux-firmware.git/tree/amd-ucode

[kib]

sys/dev/cpuctl/cpuctl.c

60

This is unrelated, commit separately (now ?).

396

Why is this required ? I do not see any harm from allowing the update to run from arbitrary /dev/cpuctlN.

428

Check for ptr != NULL is not needed. Use plain free(9).

usr.sbin/cpucontrol/amd10h.c

2

Copyright line should be updated.

[stas]

Looks good besides what kib@ already mentioned.

Thanks!

sys/dev/cpuctl/cpuctl.c

396

I agree. Unless there are restrictions on which cores the update can be performed on... But in that case the check will have to be a bit more sophisticated to account for multi-socket configurations.

usr.sbin/cpucontrol/amd10h.c

174

Double space.

[avg]

address comments from kib

[kib]

usr.sbin/cpucontrol/amd10h.c

38

sys/ headers should come before the usermode headers.

300

space after if

[avg]

really address kib's comment and replace contigfree with free

[avg]

sys/dev/cpuctl/cpuctl.c

396

There is really no restriction. I just wanted to skip unnecessary writes to the update MSR in the default configuration with microcode_cpus="ALL". But that was not needed anyway, because the first invocation of cpucontrol would update all CPUs and subsequent invocations would see that the CPUs have the latest version.

[avg]

address comments from stas

[avg]

add comments about the AMD update MSR being undocumented

[avg]

Just as a data point:

$ cpucontrol -vvv -d /boot/firmware -u /dev/cpuctl0
cpucontrol: skipping /boot/firmware/.: is a directory
cpucontrol: skipping /boot/firmware/..: is a directory
cpucontrol: found cpu family 0xf model 0x6 stepping 0x2 extfamily 0x1 extmodel 0.
cpucontrol: microcode revision 0x1000098
cpucontrol: equiv_id: 1062
cpucontrol: selecting revision: 10000c7
cpucontrol: selected ucode size is 960
/boot/firmware/microcode_amd.bin: updating cpu /dev/cpuctl0 to revision 0x10000c7... done.

$ cpucontrol -vvv -d /boot/firmware -u /dev/cpuctl1
cpucontrol: skipping /boot/firmware/.: is a directory
cpucontrol: skipping /boot/firmware/..: is a directory
cpucontrol: found cpu family 0xf model 0x6 stepping 0x2 extfamily 0x1 extmodel 0.
cpucontrol: microcode revision 0x10000c7
cpucontrol: equiv_id: 1062