[PATCH 3/3] hash: Allow for SHA512 hardware implementations

[Simon Glass]

Hi Heinrich,

On Wed, 12 May 2021 at 10:25, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> On 12.05.21 18:05, Simon Glass wrote:
> > Hi Heinrich,
> >
> > On Wed, 12 May 2021 at 10:01, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> >>
> >> On 17.02.21 04:20, Joel Stanley wrote:
> >>> Similar to support for SHA1 and SHA256, allow the use of hardware hashing
> >>> engine by enabling the algorithm and setting  CONFIG_SHA_HW_ACCEL /
> >>> CONFIG_SHA_PROG_HW_ACCEL.
> >>>
> >>> Signed-off-by: Joel Stanley <joel at jms.id.au>
> >>
> >> This merged patch leads to errors compiling the EFI TCG2 protocol on
> >> boards with CONFIG_SHA_HW_ACCEL.
> >>
> >> There is not as single implementation of hw_sha384 and hw_sha512. You
> >> could only use CONFIG_SHA_HW_ACCEL for selecting these functions if
> >> these were implemented for *all* boards with CONFIG_SHA_HW_ACCEL=y. But
> >> this will never happen.
> >>
> >> *This patch needs to be reverted.*
> >>
> >> Why do we have CONFIG_SHA_HW_ACCEL at all and don't use weak functions
> >> instead?
> >
> > This is all a mess. We should not use weak functions IMO, but instead
> > have a driver interface, like we do with filesystems.
> >
> > Part of the challenge is the need to keep code size small for
> > platforms that only need one algorithm.
>
> If a function is not referenced, the linker will eliminate it. But with
> a driver interface every function in the interface is referenced.

Indeed, but we can still have an option for enabling the progressive
interface. My point is that the implementation (software or hardware)
should use a driver.

Regards,
Simon

> Heinrich