On 22.08.20 20:05, Awan, Arsalan wrote: >> Or is this the UEFI boot services watchdog that terminates early during >> Linux boot? That's unfortunately a completely useless thing when it >> comes to A/B update monitoring. >> > Arsalan: > I'm not sure if I exactly got you here, but I want to share my experience > with this > method that the underlying hardware wdt (at least for the platforms I > mentioned) > that got configured was the same. > So whether efibootguard configures the wdt, or UEFI configures the wdt and > then > dies, the hardware wdt gets configured... and it will pop! It does! I've > tested it!
UEFI Spec 2.6, EFI_BOOT_SERVICES.SetWatchdogTimer(): "The watchdog timer is only used during boot services. On successful completion of EFI_BOOT_SERVICES.ExitBootServices() the watchdog timer is disabled." ExitBootServices is run early during Linux boot. Thus, a watchdog that is managed by UEFI is completely useless for our purposes. We've looked into that already, even started discussions with the community. The spec will have to be enhanced to make this usable (and to back its implementation also by no-way-out hw watchdogs...). Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux -- You received this message because you are subscribed to the Google Groups "EFI Boot Guard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/efibootguard-dev/6eafdeb2-bb1d-12d4-c2b7-c8c078e27c69%40siemens.com.
