Re: Locking for HW crypto accelerators

On Thu, 30 Aug 2018 at 15:27, Kamil Konieczny
[off-list ref] wrote:

On 30.08.2018 15:09, Krzysztof Kozlowski wrote:

quoted

[...]
Thanks Stephan for hints. Let's assume the each of init, update and
final are atomic... but how about the relation between update and
final? I have two concurrent users in user-space but only one HW:

Process A:             Process B:
init() and set_key()
                       init() and different key
update(some_data)
                       update(different_data)
final()
                       final()

The final() from process A will now produce the result of hashing/CRC
of some_data and different_data (and even maybe mixed with init() for
different key). All because in the meantime process B added its own
data to the HW.

Best regards,
Krzysztof

Can your hardware do export/import ?

If yes, you can use workqueue and guard HW with spinlock,
as in exynos hash in s5p-sss.c (or see other drivers).

Yes, workqueue doing all necessary HW initialization would be the
solution here as well. The point is what later Herbert wrote - I need
to take care about the HW state because the requests even for shash
will be coming in random order.

Best regards,
Krzysztof