UefiCpuPkg/CpuMpPei: Load GDT table on BSP

Load new GDT table and update segment accordingly.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17988 6f19259b-4bc3-4df7-8a09-765794883524

UefiCpuPkg/CpuMpPei/CpuMpPei.h

@@ -21,6 +21,36 @@
 #include <Library/BaseLib.h>
 #include <Library/PeimEntryPoint.h>
 
+#pragma pack(1)
+typedef union {
+  struct {
+    UINT32  LimitLow    : 16;
+    UINT32  BaseLow     : 16;
+    UINT32  BaseMid     : 8;
+    UINT32  Type        : 4;
+    UINT32  System      : 1;
+    UINT32  Dpl         : 2;
+    UINT32  Present     : 1;
+    UINT32  LimitHigh   : 4;
+    UINT32  Software    : 1;
+    UINT32  Reserved    : 1;
+    UINT32  DefaultSize : 1;
+    UINT32  Granularity : 1;
+    UINT32  BaseHigh    : 8;
+  } Bits;
+  UINT64  Uint64;
+} IA32_GDT;
+#pragma pack()
+/**
+  Assembly code to load GDT table and update segment accordingly.
+
+  @param Gdtr   Pointer to GDT descriptor
+**/
+VOID
+EFIAPI
+AsmInitializeGdt (
+  IN IA32_DESCRIPTOR  *Gdtr
+  );
 
 
 #endif