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SubjectRe: [PATCH] tpm: Document UEFI event log quirks
On 7/5/19 3:15 AM, Jarkko Sakkinen wrote:
> On Wed, 2019-07-03 at 09:45 -0700, Randy Dunlap wrote:
>>> +This introduces another problem: nothing guarantees that it is not
>>> +called before the stub gets to run. Thus, it needs to copy the final
>>> +events table preboot size to the custom configuration table so that
>>> +kernel offset it later on.

(so that)
the kernel can use that final table preboot size as an events table
offset later on.

>> ? kernel can offset it later on.
> EFI stub calculates the total size of the events in the final events
> table at the time.
> Later on, TPM driver uses this offset to copy only the events that
> were actually generated after ExitBootServices():
> /*
> * Copy any of the final events log that didn't also end up in the
> * main log. Events can be logged in both if events are generated
> * between GetEventLog() and ExitBootServices().
> */
> memcpy((void *)log->bios_event_log + log_size,
> final_tbl->events + log_tbl->final_events_preboot_size,
> efi_tpm_final_log_size);
> What would be a better way to describe this?

Yeah, I think I see what it's doing, how it's using that.
See above.



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