From 9293d6e42e677e4a38e055258c0993ad8a9df14e Mon Sep 17 00:00:00 2001
From: Jeff Fan <jeff.fan@intel.com>
Date: Wed, 19 Apr 2017 11:16:55 +0800
Subject: [PATCH] UefiCpuPkg/MpInitLib: save/restore original contents

If APs is in HLT-LOOP mode, we need AP reset vector for waking up APs. This
updating is to save/restore original contents of AP reset vector around waking
up APs always.

https://bugzilla.tianocore.org/show_bug.cgi?id=500

Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/PeiMpLib.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
index fb1d48fad8..5ce5788125 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
@@ -1,7 +1,7 @@
 /** @file
   MP initialize support functions for PEI phase.
 
-  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2016 - 2017, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -129,10 +129,8 @@ CpuMpEndOfPeiCallback (
       }
       Hob.Raw = GET_NEXT_HOB (Hob);
     }
-  } else {
-    CpuMpData->SaveRestoreFlag = TRUE;
-    RestoreWakeupBuffer (CpuMpData);
   }
+
   return EFI_SUCCESS;
 }
 
@@ -286,12 +284,8 @@ AllocateResetVector (
     CpuMpData->WakeupBuffer      = GetWakeupBuffer (ApResetVectorSize);
     CpuMpData->MpCpuExchangeInfo = (MP_CPU_EXCHANGE_INFO *) (UINTN)
                     (CpuMpData->WakeupBuffer + CpuMpData->AddressMap.RendezvousFunnelSize);
-    BackupAndPrepareWakeupBuffer (CpuMpData);
-  }
-
-  if (CpuMpData->SaveRestoreFlag) {
-    BackupAndPrepareWakeupBuffer (CpuMpData);
   }
+  BackupAndPrepareWakeupBuffer (CpuMpData);
 }
 
 /**
@@ -304,9 +298,7 @@ FreeResetVector (
   IN CPU_MP_DATA              *CpuMpData
   )
 {
-  if (CpuMpData->SaveRestoreFlag) {
-    RestoreWakeupBuffer (CpuMpData);
-  }
+  RestoreWakeupBuffer (CpuMpData);
 }
 
 /**
-- 
2.39.2