UefiCpuPkg: Move AsmRelocateApLoopStart from Mpfuncs.nasm to AmdSev.nasm

[mirror_edk2.git] / MdePkg / Library / BaseRngLib / BaseRng.c

/** @file\r
  Random number generator services that uses CPU RNG instructions to\r
  provide random numbers.\r
\r
Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>\r
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>\r
\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include <Library/BaseLib.h>\r
#include <Library/DebugLib.h>\r
\r
#include "BaseRngLibInternals.h"\r
\r
//\r
// Limited retry number when valid random data is returned.\r
// Uses the recommended value defined in Section 7.3.17 of "Intel 64 and IA-32\r
// Architectures Software Developer's Manual".\r
//\r
#define GETRANDOM_RETRY_LIMIT  10\r
\r
/**\r
  Generates a 16-bit random number.\r
\r
  if Rand is NULL, then ASSERT().\r
\r
  @param[out] Rand     Buffer pointer to store the 16-bit random value.\r
\r
  @retval TRUE         Random number generated successfully.\r
  @retval FALSE        Failed to generate the random number.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
GetRandomNumber16 (\r
  OUT     UINT16  *Rand\r
  )\r
{\r
  UINT32  Index;\r
\r
  ASSERT (Rand != NULL);\r
\r
  if (Rand == NULL) {\r
    return FALSE;\r
  }\r
\r
  if (!ArchIsRngSupported ()) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // A loop to fetch a 16 bit random value with a retry count limit.\r
  //\r
  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {\r
    if (ArchGetRandomNumber16 (Rand)) {\r
      return TRUE;\r
    }\r
  }\r
\r
  return FALSE;\r
}\r
\r
/**\r
  Generates a 32-bit random number.\r
\r
  if Rand is NULL, then ASSERT().\r
\r
  @param[out] Rand     Buffer pointer to store the 32-bit random value.\r
\r
  @retval TRUE         Random number generated successfully.\r
  @retval FALSE        Failed to generate the random number.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
GetRandomNumber32 (\r
  OUT     UINT32  *Rand\r
  )\r
{\r
  UINT32  Index;\r
\r
  ASSERT (Rand != NULL);\r
\r
  if (Rand == NULL) {\r
    return FALSE;\r
  }\r
\r
  if (!ArchIsRngSupported ()) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // A loop to fetch a 32 bit random value with a retry count limit.\r
  //\r
  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {\r
    if (ArchGetRandomNumber32 (Rand)) {\r
      return TRUE;\r
    }\r
  }\r
\r
  return FALSE;\r
}\r
\r
/**\r
  Generates a 64-bit random number.\r
\r
  if Rand is NULL, then ASSERT().\r
\r
  @param[out] Rand     Buffer pointer to store the 64-bit random value.\r
\r
  @retval TRUE         Random number generated successfully.\r
  @retval FALSE        Failed to generate the random number.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
GetRandomNumber64 (\r
  OUT     UINT64  *Rand\r
  )\r
{\r
  UINT32  Index;\r
\r
  ASSERT (Rand != NULL);\r
\r
  if (Rand == NULL) {\r
    return FALSE;\r
  }\r
\r
  if (!ArchIsRngSupported ()) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // A loop to fetch a 64 bit random value with a retry count limit.\r
  //\r
  for (Index = 0; Index < GETRANDOM_RETRY_LIMIT; Index++) {\r
    if (ArchGetRandomNumber64 (Rand)) {\r
      return TRUE;\r
    }\r
  }\r
\r
  return FALSE;\r
}\r
\r
/**\r
  Generates a 128-bit random number.\r
\r
  if Rand is NULL, then ASSERT().\r
\r
  @param[out] Rand     Buffer pointer to store the 128-bit random value.\r
\r
  @retval TRUE         Random number generated successfully.\r
  @retval FALSE        Failed to generate the random number.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
GetRandomNumber128 (\r
  OUT     UINT64  *Rand\r
  )\r
{\r
  ASSERT (Rand != NULL);\r
\r
  if (Rand == NULL) {\r
    return FALSE;\r
  }\r
\r
  if (!ArchIsRngSupported ()) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // Read first 64 bits\r
  //\r
  if (!GetRandomNumber64 (Rand)) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // Read second 64 bits\r
  //\r
  return GetRandomNumber64 (++Rand);\r
}\r