SecurityPkg/RandomNumberGenerator/RngDxe/Arm/ArmAlgo.c

   1 /** @file
   2   Arm specific code.
   3
   4   Copyright (c) 2022, Arm Limited. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6 **/
   7
   8 #include <Library/BaseLib.h>
   9 #include <Library/BaseMemoryLib.h>
  10 #include <Library/DebugLib.h>
  11 #include <Library/MemoryAllocationLib.h>
  12 #include <Library/ArmTrngLib.h>
  13
  14 #include "RngDxeInternals.h"
  15
  16 // Maximum number of Rng algorithms.
  17 #define RNG_AVAILABLE_ALGO_MAX  1
  18
  19 /** Allocate and initialize mAvailableAlgoArray with the available
  20     Rng algorithms. Also update mAvailableAlgoArrayCount.
  21
  22   @retval EFI_SUCCESS             The function completed successfully.
  23   @retval EFI_OUT_OF_RESOURCES    Could not allocate memory.
  24 **/
  25 EFI_STATUS
  26 EFIAPI
  27 GetAvailableAlgorithms (
  28   VOID
  29   )
  30 {
  31   UINT16  MajorRevision;
  32   UINT16  MinorRevision;
  33
  34   // Rng algorithms 2 times, one for the allocation, one to populate.
  35   mAvailableAlgoArray = AllocateZeroPool (RNG_AVAILABLE_ALGO_MAX);
  36   if (mAvailableAlgoArray == NULL) {
  37     return EFI_OUT_OF_RESOURCES;
  38   }
  39
  40   // Raw algorithm (Trng)
  41   if (!EFI_ERROR (GetArmTrngVersion (&MajorRevision, &MinorRevision))) {
  42     CopyMem (
  43       &mAvailableAlgoArray[mAvailableAlgoArrayCount],
  44       &gEfiRngAlgorithmRaw,
  45       sizeof (EFI_RNG_ALGORITHM)
  46       );
  47     mAvailableAlgoArrayCount++;
  48   }
  49
  50   return EFI_SUCCESS;
  51 }