[RFC PATCH] crypto: riscv: scalar accelerated GHASH

[Herbert Xu]

On Thu, Apr 17, 2025 at 02:49:38PM +0800, Qingfang Deng wrote:
>
> +static int riscv64_clmul_ghash_update(struct shash_desc *desc, const u8 *src, unsigned int srclen)
> +{
> +	struct riscv64_clmul_ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
> +	struct riscv64_clmul_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
> +	unsigned int len;
> +
> +	if (dctx->bytes) {
> +		if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
> +			memcpy(dctx->buffer + dctx->bytes, src, srclen);
> +			dctx->bytes += srclen;
> +			return 0;
> +		}
> +		memcpy(dctx->buffer + dctx->bytes, src, GHASH_DIGEST_SIZE - dctx->bytes);
> +
> +		gcm_ghash_rv64i_zbc(&dctx->shash, ctx->key, dctx->buffer, GHASH_DIGEST_SIZE);
> +
> +		src += GHASH_DIGEST_SIZE - dctx->bytes;
> +		srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
> +		dctx->bytes = 0;
> +	}

If this progresses beyond an RFC, you will need to do convert this
into a block-only algorithm on top of:

https://patchwork.kernel.org/project/linux-crypto/patch/b2eb753b083c029785c5e18238ca6cf06f48c86a.1744784515.git.herbert@gondor.apana.org.au/

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