Comment # 9 on bug 1188327 from Mian Yousaf Kaukab

(In reply to Richard Biener from comment #7)
> (In reply to Takashi Iwai from comment #6)
> > FWIW, ecc_swap_digits() handles the u64 array, so copying would be needed
> > there instead of the caller.  (And there are two calls of ecc_swap_digits()
> > in 
> > ecdsa_set_pub_key()).
> > 
> > If performance matters, we'd need two versions of ecc_swap_digits() for
> > aligned and unaligned.  But all calls of ecc_swap_digits() in ecdsa.c look
> > suspicious wrt alignment.
> 
> Instead of a memcpy you can also use
> 
> typedef u64 unaligned_u64 __attribute__((aligned(1)));
> 
>   *(unaligned_u64 *)digits
> 
> that avoids the memcpy (which should be similarly optimized in most cases,
> but you'd need to check).  It might of course be slow when the target
> cannot do unaligned accesses as it will to shifting/masking/etc. to
> produce the u64 value which might not actually be needed as 'u64' (without
> knowing the code in question)

Or may be use get_unaligned().