SecurityPkg/RandomNumberGenerator/RngDxe/X64/RdRandWord.c

   1 /** @file
   2   RDRAND Support Routines.
   3
   4 Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
   5 This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "RdRand.h"
  16
  17 /**
  18   Calls RDRAND to request a word-length random number.
  19
  20   @param[out]  Rand          Buffer pointer to store the random number.
  21   @param[in]   NeedRetry     Determine whether or not to loop retry.
  22
  23   @retval EFI_SUCCESS        Random word generation succeeded.
  24   @retval EFI_NOT_READY      Failed to request random word.
  25
  26 **/
  27 EFI_STATUS
  28 EFIAPI
  29 RdRandWord (
  30   OUT UINTN        *Rand,
  31   IN BOOLEAN       NeedRetry
  32   )
  33 {
  34   return RdRand64 (Rand, NeedRetry);
  35 }
  36
  37 /**
  38   Calls RDRAND to request multiple word-length random numbers.
  39
  40   @param[in]   Length        Size of the buffer, in words, to fill with.
  41   @param[out]  RandBuffer    Pointer to the buffer to store the random result.
  42
  43   @retval EFI_SUCCESS        Random words generation succeeded.
  44   @retval EFI_NOT_READY      Failed to request random words.
  45
  46 **/
  47 EFI_STATUS
  48 EFIAPI
  49 RdRandGetWords (
  50   IN UINTN         Length,
  51   OUT UINTN        *RandBuffer
  52   )
  53 {
  54   EFI_STATUS  Status;
  55   UINT32      Index;
  56
  57   for (Index = 0; Index < Length; Index++) {
  58     //
  59     // Obtain one word-length (64-bit) Random Number with possible retry-loop.
  60     //
  61     Status = RdRand64 (RandBuffer, TRUE);
  62     if (EFI_ERROR (Status)) {
  63       return Status;
  64     }
  65
  66     RandBuffer++;
  67   }
  68
  69   return EFI_SUCCESS;
  70 }