On Thu, Nov 05, 2020 at 12:56:55PM +0000, Andre Przywara wrote:

>  static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
>  {
> +	struct arm_smccc_res res;
>  	unsigned long val;
> -	bool ok = arch_get_random_seed_long(&val);
>  
> -	*v = val;
> -	return ok;
> +	if (cpus_have_const_cap(ARM64_HAS_RNG)) {
> +		if (arch_get_random_seed_long(&val)) {
> +			*v = val;
> +			return true;
> +		}
> +		return false;
> +	}

It isn't obvious to me why we don't fall through to trying the SMCCC
TRNG here if for some reason the v8.5-RNG didn't give us something.
Definitely an obscure possibility but still...