configs: add CONFIG_CRYPTO_NHPOLY1305_NEON=m

[plumbeo]

Enable nhpoly1305_neon module to speed up Adiantum disk encryption.

[plumbeo]

When Adiantum was enabled (issue #3648) the CONFIG_CRYPTO_NHPOLY1305_NEON option, which significantly speeds up the encryption/decryption speed, was overlooked.

On a Raspberry Pi 3B tests with cryptsetup benchmark -c xchacha12,aes-adiantum -s 256 with the current 6.6.62 64bit kernel (rebuilt from the original linux_6.6.62-1+rpt1 source package) show a 20% improvement:

encryption/decryption speed (average of 5 runs)

governor        w/o nhpoly1305_neon     w/ nhpoly1305_neon      improvement
powersave       61.7/61.7               74.8/74.7               1.21x
performance     118.3/118.4             142.2/142.1             1.20x

The option doesn't select anything else (the only diff between the config files is CONFIG_CRYPTO_NHPOLY1305_NEON=m) and the new nhpoly1305-neon.ko.xz module's size is only 2.2kb so the impact on users who don't set up Adiantum encryption is minimal.

Can the option be enabled on all kernels?

[pelwell]

BCM2835 has no NEON support, and if you use your bcmrpi_defconfig you'll find that CONFIG_CRYPTO_NHPOLY1305_NEON=m does not stick.

[plumbeo]

BCM2835 has no NEON support, and if you use your bcmrpi_defconfig you'll find that CONFIG_CRYPTO_NHPOLY1305_NEON=m does not stick.

I didn't notice that, sorry. I force pushed a new version of the patch that only touches arch/arm/configs/{bcm2709_defconfig,bcm2711_defconfig} and arch/arm64/configs/{bcm2711_defconfig,bcm2712_defconfig,bcmrpi3_defconfig}, is that ok?

[pelwell]

That looks better. I'll just let the auto-builds complete before merging. Don't worry about the checkpatch Signed-off-by error - all the config patches get squashed together.

[plumbeo]

Thank you! Do you need a separate PR for 6.12.y/6.13.y or will the commit be picked up from this branch later?

[pelwell]

It will be automatically forward-ported.