Baoquan, thanks for cc me. On Sat, 5 Nov 2022 at 11:10, Baoquan He <bhe@xxxxxxxxxx> wrote: > > Add Dave to CC > > On 10/28/22 at 01:02pm, ns@xxxxxxxx wrote: > > Greetings, > > > > I've been hitting a bug on my Lenovo ThinkPad T480 where kexecing will > > cause EFI mode (if that's the right term for it) to be unconditionally > > disabled, even when not using the --noefi option to kexec. > > > > What I mean by "EFI mode" being disabled, more than just EFI runtime > > services, is that basically nothing about the system's EFI is visible > > post-kexec. Normally you have a message like this in dmesg when the > > system is booted in EFI mode: > > > > [ 0.000000] efi: EFI v2.70 by EDK II > > [ 0.000000] efi: SMBIOS=0x7f98a000 ACPI=0x7fb7e000 ACPI 2.0=0x7fb7e014 > > MEMATTR=0x7ec63018 > > (obviously not the real firmware of the machine I'm talking about, but I > > can also send that if it would be of any help) > > > > No such message pops up in my dmesg as a result of this bug, & this > > causes some fallout like being unable to find the system's DMI > > information: > > > > <6>[ 0.000000] DMI not present or invalid. > > > > The efivarfs module also fails to load with -ENODEV. > > > > I've tried also booting with efi=runtime explicitly but it doesn't > > change anything. The kernel still does not print the name of the EFI > > firmware, DMI is still missing, & efivarfs still fails to load. > > > > I've been using the kexec_load syscall for all these tests, if it's > > important. > > > > Also, to make it very clear, all this only ever happens post-kexec. When > > booting straight from UEFI (with the EFI stub), all the aforementioned > > stuff that fails works perfectly fine (i.e. name of firmware is printed, > > DMI is properly found, & efivarfs loads & mounts just fine). > > > > This is reproducible with a vanilla 6.1-rc2 kernel. I've been trying to > > bisect it, but it seems like it goes pretty far back. I've got vanilla > > mainline kernel builds dating back to 5.17 that have the exact same > > issue. It might be worth noting that during this testing, I made sure > > the version of the kernel being kexeced & the kernel kexecing were the > > same version. It may not have been a problem in older kernels, but that > > would be difficult to test for me (a pretty important driver for this > > machine was only merged during v5.17-rc4). So it may not have been a > > regression & just a hidden problem since time immemorial. > > > > I am willing to test any patches I may get to further debug or fix > > this issue, preferably based on the current state of torvalds/linux.git. > > I can build & test kernels quite a few times per day. > > > > I can also send any important materials (kernel config, dmesg, firmware > > information, so on & so forth) on request. I'll also just mention I'm > > using kexec-tools 2.0.24 upfront, if it matters. Can you check the efi runtime in sysfs: ls /sys/firmware/efi/runtime-map/ If nothing then maybe you did not enable CONFIG_EFI_RUNTIME_MAP=y, it is needed for kexec UEFI boot on x86_64. Otherwise you can add debug printf in kexec-tools efi error path to see what is wrong. kexec/arch/i386/x86-linux-setup.c : function setup_efi_data And if it still not work please post your kernel config, I can have a try although I do not have the t480 now. > > > > Regards, > > > > _______________________________________________ > > kexec mailing list > > kexec@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/kexec > > >
