Hi, On 3/21/24 11:48 PM, Ard Biesheuvel wrote: > (cc Hans) > > On Thu, 21 Mar 2024 at 23:05, Clayton Craft <clayton@xxxxxxxxxxxxx> wrote: >> >> I've been chasing a problem with 32-bit EFI mixed mode booting on two different >> (x86_64) Intel Bay Trail platforms, where the system reboots or hangs seemingly >> very early somewhere before or after loading the kernel. I've not been able to >> get any output from the kernel or stub over efifb when the issue happens[0], and >> do not have serial console access on these systems. >> >> v6.8 fails for me, and presumably so does everything back to v6.2. v6.1 is able >> to boot OK on these platforms with mixed mode, and it looks like there are a lot >> of changes from 6.1..6.2 for EFI/mixed mode booting. > > v6.1 just received some EFI related backports, so please check the > latest v6.1.y as well. > >> I did managed to bisect the >> issue to: >> >> commit e2ab9eab324cdf240de89741e4a1aa79919f0196 >> Author: Ard Biesheuvel <ardb@xxxxxxxxxx> >> Date: Tue Nov 22 17:10:02 2022 +0100 >> >> x86/boot/compressed: Move 32-bit entrypoint code into .text section >> >> However I'm not sure how to proceed from here, or if my bisect is all that >> useful since the commit seems to be in the middle of a bunch of changes I do not >> understand. I've been using systemd-boot to test this (both the full bootloader >> and UKI w/ the sd-boot stub). Is 32-bit mixed mode on x86_64 working for others? >> > > I usually test on 32-bit OVMF built with LOAD_X64_ON_IA32_ENABLE, > which allows the use of the compat entry point. This is different from > the EFI handover protocol, and I am not sure which one you are using. > > I have never had any reports, or noticed any issues myself. Last time > I tried (some weeks ago) it was working for me. > CC'ing Hans who may have more data points. I've been offline for most of the week and I see that in the mean time you seem to have found a fix, great. FWIW I have been booting everything up to 6.8.0 on my own mixed-mode Bay Trail tablets without issues, so the problem seems to be specific to certain BIOS-es. Please Cc me on the final fix, then I can test that early and double check that things don't regress on other mixed-mode Bay Trail devices. Regards, Hans
