From c8b6f16d7d3b0c225cf34bd1c750373c9b251284 Mon Sep 17 00:00:00 2001
From: Thomas Palmer <thomas.palmer@hpe.com>
Date: Fri, 9 Oct 2015 06:03:17 +0000
Subject: [PATCH] MdePkg: Create GetRandomNumber128 in RngLib

Declare GetRandomNumber128 in RngLib.h.
Create GetRandomNumber128 in BaseRngLib, which is simply calling
GetRandomNumber64 twice.

A GetRandomNumber128 function allows platforms with 128bit HWRNGs to
save on IO overhead that comes from having to prime the HWRNG device
before each read operation.
Using the HWRNG installed on the HP ProLiant m400 moonshot cartridge,
this will save about 50ms per RAW Entropy operation as compared with
calling GetRandomNumber64 twice.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Thomas Palmer <thomas.palmer@hpe.com>
Reviewed-by: Samer El-Haj-Mahmoud <elhaj@hpe.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Qin Long <qin.long@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18590 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdePkg/Include/Library/RngLib.h     | 17 +++++++++++++++
 MdePkg/Library/BaseRngLib/BaseRng.c | 32 +++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/MdePkg/Include/Library/RngLib.h b/MdePkg/Include/Library/RngLib.h
index 157a93139c..ece4394168 100644
--- a/MdePkg/Include/Library/RngLib.h
+++ b/MdePkg/Include/Library/RngLib.h
@@ -66,4 +66,21 @@ GetRandomNumber64 (
   OUT     UINT64                    *Rand
   );
 
+/**
+  Generates a 128-bit random number.
+
+  if Rand is NULL, then ASSERT().
+
+  @param[out] Rand     Buffer pointer to store the 128-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+GetRandomNumber128 (
+  OUT     UINT64                    *Rand
+  );
+
 #endif  // __RNG_LIB_H__
diff --git a/MdePkg/Library/BaseRngLib/BaseRng.c b/MdePkg/Library/BaseRngLib/BaseRng.c
index 279df3013c..2c8df56286 100644
--- a/MdePkg/Library/BaseRngLib/BaseRng.c
+++ b/MdePkg/Library/BaseRngLib/BaseRng.c
@@ -155,3 +155,35 @@ GetRandomNumber64 (
 
   return FALSE;
 }
+
+/**
+  Generates a 128-bit random number.
+
+  if Rand is NULL, then ASSERT().
+
+  @param[out] Rand     Buffer pointer to store the 128-bit random value.
+
+  @retval TRUE         Random number generated successfully.
+  @retval FALSE        Failed to generate the random number.
+
+**/
+BOOLEAN
+EFIAPI
+GetRandomNumber128 (
+  OUT     UINT64                    *Rand
+  )
+{
+  ASSERT (Rand != NULL);
+
+  //
+  // Read first 64 bits
+  //
+  if (!GetRandomNumber64 (Rand)) {
+    return FALSE;
+  }
+
+  //
+  // Read second 64 bits
+  //
+  return GetRandomNumber64 (++Rand);
+}