Drop default y from CONFIG_EFI_GRUB_ARM32_WORKAROUND?

[Jan Kiszka]

On 06.01.26 16:34, Mark Kettenis wrote:
>> Date: Tue, 6 Jan 2026 14:47:30 +0100
>> From: Jan Kiszka <jan.kiszka at siemens.com>
> 
> Hi Jan,
> 
>> Hi,
>>
>> it seems that some kernel configs can cause problems with the
>> CONFIG_EFI_GRUB_ARM32_WORKAROUND. Namely, 6.1-cip and 5.10-cip with its
>> current defconfigs [1] no longer boot on the BeagleBone Black (other
>> boards still need validation), both with the more recommendable
>> systemd-boot and grub. I do not have the motivation to debug the reason
>> in the kernel / its config, given that everything works fine once the
>> firmware behaves according to the UEFI spec.
>>
>> Meanwhile, grub reached 2.12 now which is far away from the old, broken
>> version of 2019. So, should we rather make this workaround opt-in in 2026?
> 
> This isn't just about GRUB though.  There is also the issue with the
> the non-architected caches that are typically found on systems that
> use Cortex-A9 cores such as i.MX6.

i.MX6 is a good hint to cross-check with some related board.

But what does that mean exactly? If we turn off the workaround, not
calling cleanup_before_linux() anymore, we will then leave caches for
i.MX6, e.g., enabled, and that would also be against the spec?

 * According to the UEFI spec caches that can be managed via CP15
 * operations should be enabled. Caches requiring platform information
 * to manage should be disabled. This should not happen in
 * ExitBootServices() but before invoking any UEFI binary is invoked.

> 
> The OpenBSD bootloader used to have the same problem as those older
> versions of GRUB.  I fixed that back in 2019, and there shouldn't be
> any users left with a broken version.
> 

That's good.

Thanks,
Jan

-- 
Siemens AG, Foundational Technologies
Linux Expert Center