Hey Heinrich,
Not sure why this hasn't come up before as the issue with testing goes back to 2021.01-rc1/merge window, or if it's something like a newer firmware (I currently have one from 2021-02-25) but I'm seeing issues with the Raspberry Pi bringing up the secondary CPUs in Linux [1].
Ine of our users worked out it was a u-boot issue and with bisecting I got it down to down to the "efi_loader: consider no-map property of reserved memory" commit 4cbb293. I don't know too much about SMP bringing online CPUs on the RPi raspberry pi but I wonder if that commit is clobbering some piece of memory needed for that (I vaguely remember some mention of spin tables).
I see it on both the original RPi3 and the 3B+, what are your thoughts?
Peter
[ 0.008498] Remapping and enabling EFI services. [ 0.009304] smp: Bringing up secondary CPUs ... [ 5.042966] CPU1: failed to come online [ 5.042994] CPU1: failed in unknown state : 0x0 [ 10.085989] CPU2: failed to come online [ 10.086017] CPU2: failed in unknown state : 0x0 [ 15.128975] CPU3: failed to come online [ 15.129003] CPU3: failed in unknown state : 0x0 [ 15.129114] smp: Brought up 1 node, 1 CPU [ 15.129138] SMP: Total of 1 processors activated.