On Tue, Oct 04, 2022 at 11:46:39AM +0200, niek nooijens wrote:
> when Using the normal linux-image 5.10.0-18 I can use efibootmgr to change
> boot variables and /sys/firmware/efi/efivars is populated.
> when using the real-time variant efibootmgr and efivar report "efi variables
> are not supported on this system" and /sys/firmware/efi/efivars is empty.
> trying to insert the /lib/modules/kernel/fs/efivarfs/efivarfs.ko kernel
> module will result in a FAIL "no such file or directory" as well as modprobe.
> I therefore conclude this is a bug, and problematic since I need to load
> signed kernel-modules for our industrial etherCAT stack and really need the
> whole EFI/secure-boot/mok chain to work on the rt_kernel.
This is no bug. The EFI runtime services are explicitly disabled. The
reason is:
| The EFI runtime services are disabled by default when PREEMPT_RT is enabled,
| because measurements have shown that some EFI functions calls might take too
| much time to complete, causing large latencies which is an issue for Real-Time
| kernels.
You can enable it by adding "efi=runtime" to the kernel command line.
Bastian
--
I have never understood the female capacity to avoid a direct answer to
any question.
-- Spock, "This Side of Paradise", stardate 3417.3
