[PATCH] arm64: SHA-224/SHA-256 using ARMv8 Crypto Extensions

[Ard Biesheuvel]

On 24 March 2014 21:36, Marek Vasut <marex at denx.de> wrote:
> On Thursday, March 20, 2014 at 03:48:06 PM, Ard Biesheuvel wrote:
>> This patch adds support for the SHA-224 and SHA-256 hash algorithms using
>> the NEON based SHA-256 instructions that were introduced in ARM v8.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> ---
>
> [...]
>
>> + * Copyright (c) Alan Smithee.
>
> Email contact is missing here.
>
> [...]
>

Actually, this is mostly copied from the original sha1_generic.c. In
fact, my current v2 (which I will post shortly) has been reworked to
such an extent that I am contemplating dropping this attribution
altogether.

>> +static int sha224_init(struct shash_desc *desc)
>> +{
>> +     struct sha256_state *sctx = shash_desc_ctx(desc);
>> +
>> +     *sctx = (struct sha256_state){
>
> This cast is interesting, I don't quite understand it. Can you please explain
> that to me ?
>

http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html

>> +             .state = {
>> +                     SHA224_H0, SHA224_H1, SHA224_H2, SHA224_H3,
>> +                     SHA224_H4, SHA224_H5, SHA224_H6, SHA224_H7,
>> +             }
>> +     };
>> +     return 0;
>> +}
>
> [...]
>
>> +static int sha224_final(struct shash_desc *desc, u8 *out)
>> +{
>> +     struct sha256_state *sctx = shash_desc_ctx(desc);
>> +     __be32 *dst = (__be32 *)out;
>> +     int i;
>> +
>> +     sha2_final(desc);
>> +
>> +     for (i = 0; i < SHA224_DIGEST_SIZE / sizeof(*dst); i++)
>> +             dst[i] = cpu_to_be32(sctx->state[i]);
>
> Won't this cause unaligned access if *dst is not aligned to 32 bytes ?
>

arm64 does not care about that, but I agree it would be better (and
more explicit) to use put_unaligned() here, and leave it up to the
architecture to allow it or work around it.
WIll update that in v2.

Thanks for the review.

-- 
Ard.