On Wednesday 11 June 2014 10:16:03 Paolo Bonzini wrote:
If kernels actually do use the UEFI runtime services and have no need for direct access to an RTC when runing in a UEFI compliant system, then I agree with not specifying the hardware details.
The RTC is not needed for ordinary operation of the kernel and, in the current kernel, the EFI RTC driver is only used for IA64. However, it seems to be platform independent. I'll give it a shot (on x86, since that's the only architecture for which I know how to get UEFI firmware).
Using the EFI RTC seems appropriate for ARM, as it's a reasonable abstraction that should work with any hypervisor. I suspect the only reason we don't use it on x86 is that we know which RTC hardware we have and the kernel comes with a mandatory driver already.
Arnd