Re: [PATCH v1 8/8] SecurityPkg/RngDxe: Simplify Rng algorithm selection for Arm

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Pierre,

Thank you for this patch.

These changes look good to me.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

On 09/05/2023 08:40 am, pierre.gondois@arm.com wrote:
> From: Pierre Gondois <pierre.gondois@arm.com>
>
> The first element of mAvailableAlgoArray is defined as the default
> Rng algorithm to use. Don't go through the array at each RngGetRNG()
> call and just return the first element of the array.
>
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---
>   .../RandomNumberGenerator/RngDxe/ArmRngDxe.c    | 17 ++++-------------
>   1 file changed, 4 insertions(+), 13 deletions(-)
>
> diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/ArmRngDxe.c b/SecurityPkg/RandomNumberGenerator/RngDxe/ArmRngDxe.c
> index 78a18c5e1177..7a42e3cbe3d2 100644
> --- a/SecurityPkg/RandomNumberGenerator/RngDxe/ArmRngDxe.c
> +++ b/SecurityPkg/RandomNumberGenerator/RngDxe/ArmRngDxe.c
> @@ -77,7 +77,6 @@ RngGetRNG (
>     )
>   {
>     EFI_STATUS  Status;
> -  UINTN       Index;
>     GUID        RngGuid;
>   
>     if ((This == NULL) || (RNGValueLength == 0) || (RNGValue == NULL)) {
> @@ -88,21 +87,13 @@ RngGetRNG (
>       //
>       // Use the default RNG algorithm if RNGAlgorithm is NULL.
>       //
> -    for (Index = 0; Index < mAvailableAlgoArrayCount; Index++) {
> -      if (!IsZeroGuid (&mAvailableAlgoArray[Index])) {
> -        RNGAlgorithm = &mAvailableAlgoArray[Index];
> -        goto FoundAlgo;
> -      }
> -    }
> -
> -    if (Index == mAvailableAlgoArrayCount) {
> -      // No algorithm available.
> -      ASSERT (Index != mAvailableAlgoArrayCount);
> -      return EFI_DEVICE_ERROR;
> +    if (mAvailableAlgoArrayCount != 0) {
> +      RNGAlgorithm = &mAvailableAlgoArray[0];
> +    } else {
> +      return EFI_UNSUPPORTED;
>       }
>     }
>   
> -FoundAlgo:
>     Status = GetRngGuid (&RngGuid);
>     if (!EFI_ERROR (Status) &&
>         CompareGuid (RNGAlgorithm, &RngGuid))