Re: [PATCH] lib/crypto: sparc: Drop optimized MD5 code

[Eric Biggers]

On Thu, Mar 26, 2026 at 10:51:01PM +0100, John Paul Adrian Glaubitz wrote:
> On Thu, 2026-03-26 at 13:33 -0700, Eric Biggers wrote:
> > MD5 is obsolete.  Continuing to maintain architecture-optimized
> > implementations of MD5 is unnecessary and risky.  It diverts resources
> > from the modern algorithms that are actually important.
> 
> Why is it risky? That makes no sense.

Because there can be issues in architecture-optimized algorithm
implementations that don't exist in the generic implementations.  That's
a very common class of issue that has repeated over time.

> I also don't see how it diverts resources as no one is forced to work
> on the code.
> 
> SPARC is an architecture used by hobbyists and in space these days (in
> the form of Leon). I don't think any other kernel developer will have
> to take a look at it.

Huh?  We've been refactoring how the various crypto and CRC algorithms
are integrated, for all architectures.

So people outside the SPARC community, especially myself, been having to
spend quite a bit of time updating the SPARC code so that it can still
be used.

And this isn't new.  I've had to patch arch/sparc/crypto/ many times
over the years as things change in the crypto subsystem.  Many other
people, again outside the SPARC community, have as well.

The fact that you're denying that we've had to do this is really
frustrating.  There is a significant maintenance cost to keeping this
code working, which is being paid by people outside the SPARC community.

It seems best to at least focus that effort on modern algorithms like
AES and SHA-256, and not obsolete ones like MD5 and DES.  Note that
dropping those eliminates the need to add them to QEMU, as well.

I think that makes things easier for everyone.

- Eric