Re: [PATCH] crypto/arm64: sm4 - Drop cpu feature table for PMULL

[Eric Biggers]

On Mon, Nov 09, 2026 at 05:10:52PM +0100, Uwe Kleine-König wrote:
> The result of having that table is that the sm4-ce-gcm module is
> autoloaded if the CPU supports the PMULL cpu feature. However that
> module is only usefull if there are both SM4 and PMULL. The module is
> already auto-loaded if the CPU has SM4 and calls sm4_ce_gcm_init() then
> which fails without PMULL.
> 
> So dropping the PMULL cpu feature table has the only affect that on
> machines with PMULL but without SM4 the useless module isn't loaded any
> more.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxx>
> ---
> Hello,
> 
> PSA: I don't know what these cpu features are and what the sm4-ce-gcm
> module does. I just stumbled over that MODULE_DEVICE_TABLE(cpu, ...) and
> convinced myself by looking at the code about the above analysis. It
> wouldn't be a big surprise to me if I missed something relevant. So
> please apply some distrust before the patch.

I guess this and your other patch look fine, if Herbert wants to apply
them.  Note that we've actually been moving away from having separate
modules for the architecture-optimized crypto code, and when that
happens to this code the MODULE_DEVICE_TABLE will go away anyway.

- Eric