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Groups > linux.debian.kernel > #76428 > unrolled thread
| Started by | Bastian Blank <waldi@debian.org> |
|---|---|
| First post | 2022-10-04 15:00 +0200 |
| Last post | 2022-10-07 10:10 +0200 |
| Articles | 2 — 1 participant |
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Bug#1021245: linux-image-5.10.0-18-rt-amd64: can't access EFIVARS when using rt version of kernel Bastian Blank <waldi@debian.org> - 2022-10-04 15:00 +0200
Bug#1021245: linux-image-5.10.0-18-rt-amd64: can't access EFIVARS when using rt version of kernel Bastian Blank <waldi@debian.org> - 2022-10-07 10:10 +0200
| From | Bastian Blank <waldi@debian.org> |
|---|---|
| Date | 2022-10-04 15:00 +0200 |
| Subject | Bug#1021245: linux-image-5.10.0-18-rt-amd64: can't access EFIVARS when using rt version of kernel |
| Message-ID | <FcPGF-bZyc-1@gated-at.bofh.it> |
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
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| From | Bastian Blank <waldi@debian.org> |
|---|---|
| Date | 2022-10-07 10:10 +0200 |
| Message-ID | <FdQAG-cCcd-1@gated-at.bofh.it> |
| In reply to | #76428 |
[Removed OP] On Tue, Oct 04, 2022 at 02:46:14PM +0200, Bastian Blank wrote: > This is no bug. The EFI runtime services are explicitly disabled. The > reason is: > You can enable it by adding "efi=runtime" to the kernel command line. I think we should enable that by default, given that we expect several packages to write efi variables during the normal runtime. And not been able to do such critical tasks is kind of suprising. Bastian -- You're dead, Jim. -- McCoy, "The Tholian Web", stardate unknown
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