UefiCpuPkg/MpInitLib: Skip reading PlatformId on AMD processors.

[mirror_edk2.git] / UefiCpuPkg / Library / MpInitLib / MpLib.c

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index d0fbc17ce5516ae0ab07bde8460fa07f185b8426..64a4c3546e22f254b463a2b4ee279b6e118aba64 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -2,6 +2,8 @@
   CPU MP Initialize Library common functions.\r
 \r
   Copyright (c) 2016 - 2020, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2020, AMD Inc. All rights reserved.<BR>\r
+\r
   SPDX-License-Identifier: BSD-2-Clause-Patent\r
 \r
 **/\r
@@ -10,6 +12,30 @@
 \r
 EFI_GUID mCpuInitMpLibHobGuid = CPU_INIT_MP_LIB_HOB_GUID;\r
 \r
+\r
+/**\r
+  Determine if the standard CPU signature is "AuthenticAMD".\r
+\r
+  @retval TRUE  The CPU signature matches.\r
+  @retval FALSE The CPU signature does not match.\r
+\r
+**/\r
+STATIC\r
+BOOLEAN\r
+StandardSignatureIsAuthenticAMD (\r
+  VOID\r
+  )\r
+{\r
+  UINT32  RegEbx;\r
+  UINT32  RegEcx;\r
+  UINT32  RegEdx;\r
+\r
+  AsmCpuid (CPUID_SIGNATURE, NULL, &RegEbx, &RegEcx, &RegEdx);\r
+  return (RegEbx == CPUID_SIGNATURE_AUTHENTIC_AMD_EBX &&\r
+          RegEcx == CPUID_SIGNATURE_AUTHENTIC_AMD_ECX &&\r
+          RegEdx == CPUID_SIGNATURE_AUTHENTIC_AMD_EDX);\r
+}\r
+\r
 /**\r
   The function will check if BSP Execute Disable is enabled.\r
 \r
@@ -564,8 +590,13 @@ InitializeApData (
   CpuMpData->CpuData[ProcessorNumber].Waiting    = FALSE;\r
   CpuMpData->CpuData[ProcessorNumber].CpuHealthy = (BistData == 0) ? TRUE : FALSE;\r
 \r
-  PlatformIdMsr.Uint64 = AsmReadMsr64 (MSR_IA32_PLATFORM_ID);\r
-  CpuMpData->CpuData[ProcessorNumber].PlatformId = (UINT8) PlatformIdMsr.Bits.PlatformId;\r
+  //\r
+  // NOTE: PlatformId is not relevant on AMD platforms.\r
+  //\r
+  if (!StandardSignatureIsAuthenticAMD ()) {\r
+    PlatformIdMsr.Uint64 = AsmReadMsr64 (MSR_IA32_PLATFORM_ID);\r
+    CpuMpData->CpuData[ProcessorNumber].PlatformId = (UINT8)PlatformIdMsr.Bits.PlatformId;\r
+  }\r
 \r
   AsmCpuid (\r
     CPUID_VERSION_INFO,\r