Hi Following a discussion with Civil Infrastructure Project TSC, there is a watchdog protection issue with EFI: the time between the call to ExitBootService and Linux kernel takes over watchdog service is not covered by any watchdog protection.
The EFI specification for BS.SetWatchdogTimer is very flexible as it states "perform a platform specific action that must eventually cause the platform to be reset.". So we could naively implement a solution that would arm platform hardware watchdog in addition to EFI timer. Assuming watchdog period is long enough that it cover the time for Linux to take over the hardware watchdog, there is nothing to be done in EFI Stub to benefit from the new protection. But this scheme fails to handle FF-A update capsules which can take a long time. So either the period is long enough to support that or we need a FF-A watchdog service. Based on Siemens feedback, time to update can last 20 minutes. StandAloneMM may also need such a protection so FF-A watchdog service seems desired. I'd be happy to receive feedback on the problem itself (watchdog in EFI) and on the possible solution (FF-A based). Cheers FF _______________________________________________ boot-architecture mailing list boot-architecture@lists.linaro.org https://lists.linaro.org/mailman/listinfo/boot-architecture
