RE: [v6 PATCH 0/7] crypto: stm32 - Save and restore between each request

[<lionel.debieve@foss.st.com>]

Hi All,

Sorry for the very (very very) late response.
Thanks for highlighting the issue. I'm worried about the issue seen that
we've fixed at our downstream level.
We (ST) are currently working on upstreaming the new peripheral update for
STM32MP13 that fixed the old issue seen (such as CSR register numbers), and
so on....

The issue about the context management relies on a question I've get time to
ask you. There is no internal test purpose (using test manager) that really
show the need of a hash update that needs to be "self-content". We've seen
the issue using openssl use cases that is not using import/export.
I'm wondering to understand the real need of import/export in the framework
if the request must be safe itself?

From hardware point of view, it is a penalty to wait for completion to save
the context after each request. I understand the need of multiple hash
request in // but I was wondering that it can be managed by the
import/export, but it seems I was wrong. The penalty of the context saving
will impact all hash requests where, in a runtime context is probably not
the most important use case.
I'm looking deeper to check with the DMA use case and there is some new HW
restriction on the coming hash version that doesn't allow the read of CSR
register at some times.

BR,
Lionel


ST Restricted

-----Original Message-----
From: Herbert Xu <herbert@gondor.apana.org.au> 
Sent: Monday, March 6, 2023 5:42 AM
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Lionel Debieve <lionel.debieve@foss.st.com>; Li kunyu
<kunyu@nfschina.com>; davem@davemloft.net;
linux-arm-kernel@lists.infradead.org; linux-crypto@vger.kernel.org;
linux-kernel@vger.kernel.org; linux-stm32@st-md-mailman.stormreply.com;
mcoquelin.stm32@gmail.com
Subject: [v6 PATCH 0/7] crypto: stm32 - Save and restore between each
request

On Sat, Mar 04, 2023 at 05:34:04PM +0800, Herbert Xu wrote:
> 
> I've split the patch up into smaller chunks for easier testing.

v6 fixes a bug in the finup patch that caused the new data to be discarded
instead of hashed.

This patch series fixes the import/export functions in the stm32 driver.  As
usual, a failure in import/export indicates a general bug in the hash driver
that may break as soon as two concurrent users show up and hash at the same
time using any method other than digest or init+finup.

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page:
http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt