From 1e3f7a3782f1928a19bba81d9d0dba28d15fdae5 Mon Sep 17 00:00:00 2001
From: Eric Dong <eric.dong@intel.com>
Date: Thu, 19 Oct 2017 10:40:16 +0800
Subject: [PATCH] UefiCpuPkg/MpInitLib: Avoid call PcdGet* in Ap & Bsp.

MicrocodeDetect function will run by every threads, and it will
use PcdGet to get PcdCpuMicrocodePatchAddress and
PcdCpuMicrocodePatchRegionSize, if change both PCD default to dynamic,
system will in non-deterministic behavior.

By design, UEFI/PI services are single threaded and not re-entrant
so Multi processor code should not use UEFI/PI services. Here, Pcd
protocol/PPI is used to access dynamic PCDs so it would result in
non-deterministic behavior.

This code get PCD value in BSP and save them in CPU_MP_DATA for Ap.

https://bugzilla.tianocore.org/show_bug.cgi?id=726

Cc: Crystal Lee <CrystalLee@ami.com.tw>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/Microcode.c | 12 ++++--------
 UefiCpuPkg/Library/MpInitLib/MpLib.c     |  2 ++
 UefiCpuPkg/Library/MpInitLib/MpLib.h     |  2 ++
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/Microcode.c b/UefiCpuPkg/Library/MpInitLib/Microcode.c
index 982995be7d..9d61da6c23 100644
--- a/UefiCpuPkg/Library/MpInitLib/Microcode.c
+++ b/UefiCpuPkg/Library/MpInitLib/Microcode.c
@@ -1,7 +1,7 @@
 /** @file
   Implementation of loading microcode on processors.
 
-  Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2015 - 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
@@ -42,8 +42,6 @@ MicrocodeDetect (
   IN CPU_MP_DATA             *CpuMpData
   )
 {
-  UINT64                                  MicrocodePatchAddress;
-  UINT64                                  MicrocodePatchRegionSize;
   UINT32                                  ExtendedTableLength;
   UINT32                                  ExtendedTableCount;
   CPU_MICROCODE_EXTENDED_TABLE            *ExtendedTable;
@@ -61,9 +59,7 @@ MicrocodeDetect (
   VOID                                    *MicrocodeData;
   MSR_IA32_PLATFORM_ID_REGISTER           PlatformIdMsr;
 
-  MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);
-  MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);
-  if (MicrocodePatchRegionSize == 0) {
+  if (CpuMpData->MicrocodePatchRegionSize == 0) {
     //
     // There is no microcode patches
     //
@@ -93,8 +89,8 @@ MicrocodeDetect (
 
   LatestRevision = 0;
   MicrocodeData  = NULL;
-  MicrocodeEnd = (UINTN) (MicrocodePatchAddress + MicrocodePatchRegionSize);
-  MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN) MicrocodePatchAddress;
+  MicrocodeEnd = (UINTN) (CpuMpData->MicrocodePatchAddress + CpuMpData->MicrocodePatchRegionSize);
+  MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN) CpuMpData->MicrocodePatchAddress;
   do {
     //
     // Check if the microcode is for the Cpu and the version is newer
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 924b9097f2..f3ee6d4436 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -1458,6 +1458,8 @@ MpInitLibInitialize (
   CpuMpData->SwitchBspFlag    = FALSE;
   CpuMpData->CpuData          = (CPU_AP_DATA *) (CpuMpData + 1);
   CpuMpData->CpuInfoInHob     = (UINT64) (UINTN) (CpuMpData->CpuData + MaxLogicalProcessorNumber);
+  CpuMpData->MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);
+  CpuMpData->MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);
   InitializeSpinLock(&CpuMpData->MpLock);
   //
   // Save BSP's Control registers to APs
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 19defdaf4b..84ae24f88d 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -233,6 +233,8 @@ struct _CPU_MP_DATA {
   UINT8                          Vector;
   BOOLEAN                        PeriodicMode;
   BOOLEAN                        TimerInterruptState;
+  UINT64                         MicrocodePatchAddress;
+  UINT64                         MicrocodePatchRegionSize;
 };
 
 extern EFI_GUID mCpuInitMpLibHobGuid;
-- 
2.39.2