Re: Locking for HW crypto accelerators
From: Krzysztof Kozlowski
Date: Thu Aug 30 2018 - 10:00:07 EST
On Thu, 30 Aug 2018 at 15:27, Kamil Konieczny
> On 30.08.2018 15:09, Krzysztof Kozlowski wrote:
> > [...]
> > 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.