On Tue, Jan 22, 2019 at 03:14:13AM +0100, Krystian Lewandowski wrote: > Hello misc@, > > I’m trying to boot OpenBSD (current) on iMac Pro (iMacPro1,1). > It’s Apple’s Xeon-W based PC with ECC memory. > > This machine is very picky when it comes to OS support. Obviously macOS is > well > supported and I don’t have problems with it, MS Windows on an > external USB drive is stable as well. > I tried whole BSD family, multiple Linux based distros and Illumos. The only > Linux distribution I was able to boot and install was Clear Linux* - ended up > with kernel > panicking randomly, and regarding BSDs - I was able to install and boot > FreeBSD > but it randomly fails with a Machine Check Exceptions. > > The other interesting thing is infamous T2 chip in which iMac Pro is equipped > - > almost every crash ends up with BridgeOS crash report. > > I would consider OpenBSD assertion failures and FreeBSD MCA errors > "UNCORR PCC GCACHE L2 ERR error" as valid if it wasn’t for rock stable macOS > and > MS Windows (and on both it’s pushed hard at times, for a few hours straight, > incl. VMs). > And my understanding is that this iMac Pro is no exception - other iMacs > present > similar behaviour (ending up with similar T2 chip Bridge OS crash reports). > > I tried to do my homework and installed OpenBSD on an external USB drive via > VMWare Fusion and built kernel with DEBUG flag. > External USB drive is the only option because of T2 chip. > > Tried to boot .SP kernel, tried to disable some devices - though probably > doesn’t matter because I assume it’s crashing before autoconf is even > involved. > I also, tried to update microcode at boot on FreeBSD - someone suggested that > via Twitter - didn’t help for at runtime MCA faults (CPU had most recent > microcode). > > OpenBSD snapshot fails with: > "fatal machine check in supervisor mode" > "panic: trap type 18, code=0, pc=…" > https://www.dropbox.com/s/birtxskxayjvxht/OpenBSD%20default%20kernel.jpeg?dl=0 >
This may be related to a set of recent changes I made. Can you try 6.4-RELEASE and see if that still panics? -ml > The only mention I found regarding this issue and potential solution - other > than > replacing potentially faulty CPU - was to turn off the BIOS option > “Page directory cache”, for “older Linux kernels”: > https://virtuallyfun.com/wordpress/2009/09/01/openbsd-amd64-fun/ > But there is no standard BIOS or anything similar on this Apple PC. > > Debug kernel fails with something similar to: > "kernel: machine check trap, code=0" > "Stopped at uvm_pmr_assertvalid+0xd6: testq %rsi,%rsi" > https://www.dropbox.com/s/08nvew3ajk5cs7e/OpenBSD%20DEBUG%20kernel.jpeg?dl=0 > > Other crashes (from different tries): > https://www.dropbox.com/s/di4dbeju0uwyfvt/Crash%20default.jpeg?dl=0 > https://www.dropbox.com/s/5pkf64afjnixv1b/Crash%20DEBUG.jpeg?dl=0 > https://www.dropbox.com/s/q0dieiwkisj1ilr/Crash%20default%202.png?dl=0 > > PC reboots soon after (USB keyboard doesn’t work anyway). > > FreeBSD MSA crash: > https://www.dropbox.com/s/66dmjjqhbwyd194/FreeBSD%20MCA.jpeg?dl=0 > > After a few weeks of throwing different OpenBSD kernels, BSD, Linux based > distributions at this iMac I decided to post here, maybe someone would have an > idea how to improve OpenBSD experience on this machine. ;) > > I understand that I just may be doomed and have to accept facts - either it’s > broken > by design or faulty CPU must be replaced, and it’s just a hobby project - > especially > I’d like to play/learn more about arm/arm64 boards and OpenBSD - > but if there is even a slight chance to boot it on iMac… > > Thank you for any hint, > Krystian > > I wasn't sure how I could share images, decided to use Dropbox. >
