[PATCH v2 5/6] crypto/fsl: instantiate the RNG with prediciton resistance

[Horia Geantă]

On 6/4/2020 6:48 PM, Michael Walle wrote:
> +static int deinstantiate_rng(u8 sec_idx, int state_handle_mask)
> +{
> +	u32 *desc;
> +	int sh_idx, ret = 0;
> +	int desc_size = sizeof(u32) * 3;
As you mentioned, descriptor size should be sizeof(u32) * 2.

> +
> +	desc = memalign(ARCH_DMA_MINALIGN, desc_size);
> +	if (!desc) {
> +		debug("cannot allocate RNG init descriptor memory\n");
> +		return -ENOMEM;
> +	}
> +
> +	for (sh_idx = 0; sh_idx < RNG4_MAX_HANDLES; sh_idx++) {
> +		/*
> +		 * If the corresponding bit is set, then it means the state
> +		 * handle was initialized by us, and thus it needs to be
> +		 * deinitialized as well
> +		 */
> +
> +		if (state_handle_mask & RDSTA_IF(sh_idx)) {
> +			/*
> +			 * Create the descriptor for deinstantating this state
> +			 * handle.
> +			 */
> +			inline_cnstr_jobdesc_rng_deinstantiation(desc, sh_idx);
> +			flush_dcache_range((unsigned long)desc,
> +					   (unsigned long)desc + desc_size);
Shouldn't this be roundup(desc_size, ARCH_DMA_MINALIGN) instead of desc_size?

> @@ -466,9 +511,18 @@ static int instantiate_rng(u8 sec_idx, int gen_sk)
>  		 * If the corresponding bit is set, this state handle
>  		 * was initialized by somebody else, so it's left alone.
>  		 */
> -		rdsta_val = sec_in32(&rng->rdsta) & RNG_STATE_HANDLE_MASK;
> -		if (rdsta_val & (1 << sh_idx))
> -			continue;
> +		rdsta_val = sec_in32(&rng->rdsta);
> +		if (rdsta_val & (RDSTA_IF(sh_idx) | RDSTA_PR(sh_idx))) {
Adding RDSTA_PR(sh_idx) to the mask is not needed,
PR bit is meaningless without IF bit set.

> +			if (rdsta_val & RDSTA_PR(sh_idx))
> +				continue;
Could combine the condition here with the outer if condition:
		if (rdsta_val & RDSTA_IF(sh_idx) && !(rdsta_val & RDSTA_PR(sh_idx))) {

> +
> +			printf("SEC%u:  RNG4 SH%d was instantiated w/o prediction resistance. Tearing it down\n",
> +			       sec_idx, sh_idx);
> +
> +			ret = deinstantiate_rng(sec_idx, RDSTA_IF(sh_idx));
> +			if (ret)
> +				break;
> +		}

Horia