Re: RFC: s390/crypto: Add hardware acceleration for HMAC modes

[Harald Freudenberger <freude@linux.ibm.com>]

On 2024-08-13 10:12, Herbert Xu wrote:
> On Tue, Aug 13, 2024 at 09:37:24AM +0200, Harald Freudenberger wrote:
>> 
>> +static int hash(const u8 *in, unsigned int inlen,
>> +		u8 *digest, unsigned int digestsize)
>> +{
>> +	struct crypto_shash *htfm;
>> +	const char *alg_name;
>> +	int ret;
>> +
>> +	switch (digestsize) {
>> +	case SHA224_DIGEST_SIZE:
>> +		alg_name = "sha224";
>> +		break;
>> +	case SHA256_DIGEST_SIZE:
>> +		alg_name = "sha256";
>> +		break;
>> +	case SHA384_DIGEST_SIZE:
>> +		alg_name = "sha384";
>> +		break;
>> +	case SHA512_DIGEST_SIZE:
>> +		alg_name = "sha512";
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	htfm = crypto_alloc_shash(alg_name, 0, CRYPTO_ALG_NEED_FALLBACK);
>> +	if (IS_ERR(htfm))
>> +		return PTR_ERR(htfm);
>> +
>> +	ret = crypto_shash_tfm_digest(htfm, in, inlen, digest);
>> +	if (ret)
>> +		pr_err("shash digest error: %d\n", ret);
>> +
>> +	crypto_free_shash(htfm);
>> +	return ret;
>> +}
> 
> The setkey function can be called in softirq context.  Therefore
> calling crypto_alloc_* from it is not allowed.  You could either
> move the allocation to init_tfm and carry it throughout the life
> of the tfm, or perhaps you could call the s390 underlying sha hash
> function directly?
> 
> Cheers,

Ok, good catch. I'll discuss this with Holger when he is back from 
vacation.

Thanks for your work.