1 files changed, 181 insertions, 0 deletions
diff --git a/OvmfPkg/Library/LoadLinuxLib/LinuxGdt.c b/OvmfPkg/Library/LoadLinuxLib/LinuxGdt.c
new file mode 100644
index 0000000000..4e20436246
--- /dev/null
+++ b/OvmfPkg/Library/LoadLinuxLib/LinuxGdt.c
@@ -0,0 +1,181 @@
+/** @file
+  Initialize GDT for Linux.
+
+  Copyright (c) 2006 - 2012, 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
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "LoadLinuxLib.h"
+
+
+//
+// Local structure definitions
+//
+
+#pragma pack (1)
+
+//
+// Global Descriptor Entry structures
+//
+
+typedef struct _GDT_ENTRY {
+  UINT16 Limit15_0;
+  UINT16 Base15_0;
+  UINT8  Base23_16;
+  UINT8  Type;
+  UINT8  Limit19_16_and_flags;
+  UINT8  Base31_24;
+} GDT_ENTRY;
+
+typedef
+struct _GDT_ENTRIES {
+  GDT_ENTRY Null;
+  GDT_ENTRY Null2;
+  GDT_ENTRY Linear;
+  GDT_ENTRY LinearCode;
+  GDT_ENTRY TaskSegment;
+  GDT_ENTRY Spare4;
+  GDT_ENTRY Spare5;
+} GDT_ENTRIES;
+
+#pragma pack ()
+
+STATIC GDT_ENTRIES *mGdt = NULL;
+
+//
+// Global descriptor table (GDT) Template
+//
+STATIC GDT_ENTRIES GdtTemplate = {
+  //
+  // Null
+  //
+  {
+    0x0,            // limit 15:0
+    0x0,            // base 15:0
+    0x0,            // base 23:16
+    0x0,            // type
+    0x0,            // limit 19:16, flags
+    0x0,            // base 31:24
+  },
+  //
+  // Null2
+  //
+  {
+    0x0,            // limit 15:0
+    0x0,            // base 15:0
+    0x0,            // base 23:16
+    0x0,            // type
+    0x0,            // limit 19:16, flags
+    0x0,            // base 31:24
+  },
+  //
+  // Linear
+  //
+  {
+    0x0FFFF,        // limit 0xFFFFF
+    0x0,            // base 0
+    0x0,
+    0x09A,          // present, ring 0, data, expand-up, writable
+    0x0CF,          // page-granular, 32-bit
+    0x0,
+  },
+  //
+  // LinearCode
+  //
+  {
+    0x0FFFF,        // limit 0xFFFFF
+    0x0,            // base 0
+    0x0,
+    0x092,          // present, ring 0, data, expand-up, writable
+    0x0CF,          // page-granular, 32-bit
+    0x0,
+  },
+  //
+  // TaskSegment
+  //
+  {
+    0x0,            // limit 0
+    0x0,            // base 0
+    0x0,
+    0x089,          // ?
+    0x080,          // ?
+    0x0,
+  },
+  //
+  // Spare4
+  //
+  {
+    0x0,            // limit 0
+    0x0,            // base 0
+    0x0,
+    0x0,            // present, ring 0, data, expand-up, writable
+    0x0,            // page-granular, 32-bit
+    0x0,
+  },
+  //
+  // Spare5
+  //
+  {
+    0x0,            // limit 0
+    0x0,            // base 0
+    0x0,
+    0x0,            // present, ring 0, data, expand-up, writable
+    0x0,            // page-granular, 32-bit
+    0x0,
+  },
+};
+
+/**
+  Initialize Global Descriptor Table.
+
+**/
+VOID
+InitLinuxDescriptorTables (
+  VOID
+  )
+{
+  //
+  // Allocate Runtime Data for the GDT
+  //
+  mGdt = AllocateRuntimePool (sizeof (GdtTemplate) + 8);
+  ASSERT (mGdt != NULL);
+  mGdt = ALIGN_POINTER (mGdt, 8);
+
+  //
+  // Initialize all GDT entries
+  //
+  CopyMem (mGdt, &GdtTemplate, sizeof (GdtTemplate));
+
+}
+
+/**
+  Initialize Global Descriptor Table.
+
+**/
+VOID
+SetLinuxDescriptorTables (
+  VOID
+  )
+{
+  IA32_DESCRIPTOR GdtPtr;
+  IA32_DESCRIPTOR IdtPtr;
+
+  //
+  // Write GDT register
+  //
+  GdtPtr.Base = (UINT32)(UINTN)(VOID*) mGdt;
+  GdtPtr.Limit = (UINT16) (sizeof (GdtTemplate) - 1);
+  AsmWriteGdtr (&GdtPtr);
+
+  IdtPtr.Base = (UINT32) 0;
+  IdtPtr.Limit = (UINT16) 0;
+  AsmWriteIdtr (&IdtPtr);
+}
+