1 files changed, 103 insertions, 0 deletions
diff --git a/roms/edk2/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c b/roms/edk2/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c
new file mode 100644
index 000000000..001fc6f8f
--- /dev/null
+++ b/roms/edk2/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c
@@ -0,0 +1,103 @@
+/** @file
+  Execute 32-bit code in Long Mode.
+  Provide a thunk function to transition from long mode to compatibility mode to execute 32-bit code and then transit
+  back to long mode.
+
+  Copyright (c) 2014 - 2018, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <Library/BaseLib.h>
+#include <FspEas.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()
+
+GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT mGdtEntries[] = {
+  {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x0:  reserve */
+  {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x8:  compatibility mode */
+  {{0xFFFF, 0,  0,  0xB,  1,  0,  1,  0xF,  0,  1, 0,  1,  0}}, /* 0x10: for long mode */
+  {{0xFFFF, 0,  0,  0x3,  1,  0,  1,  0xF,  0,  0, 1,  1,  0}}, /* 0x18: data */
+  {{0,      0,  0,  0,    0,  0,  0,  0,    0,  0, 0,  0,  0}}, /* 0x20: reserve */
+};
+
+//
+// IA32 Gdt register
+//
+GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = {
+  sizeof (mGdtEntries) - 1,
+  (UINTN) mGdtEntries
+  };
+
+/**
+  Assembly function to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+  long mode.
+
+  @param[in] Function     The 32bit code entry to be executed.
+  @param[in] Param1       The first parameter to pass to 32bit code
+  @param[in] Param2       The second parameter to pass to 32bit code
+  @param[in] InternalGdtr The GDT and GDT descriptor used by this library
+
+  @return status.
+**/
+UINT32
+EFIAPI
+AsmExecute32BitCode (
+  IN UINT64           Function,
+  IN UINT64           Param1,
+  IN UINT64           Param2,
+  IN IA32_DESCRIPTOR  *InternalGdtr
+  );
+
+/**
+  Wrapper for a thunk  to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+  long mode.
+
+  @param[in] Function     The 32bit code entry to be executed.
+  @param[in] Param1       The first parameter to pass to 32bit code.
+  @param[in] Param2       The second parameter to pass to 32bit code.
+
+  @return EFI_STATUS.
+**/
+EFI_STATUS
+Execute32BitCode (
+  IN UINT64      Function,
+  IN UINT64      Param1,
+  IN UINT64      Param2
+  )
+{
+  EFI_STATUS       Status;
+  IA32_DESCRIPTOR  Idtr;
+
+  //
+  // Idtr might be changed inside of FSP. 32bit FSP only knows the <4G address.
+  // If IDTR.Base is >4G, FSP can not handle. So we need save/restore IDTR here for X64 only.
+  // Interrupt is already disabled here, so it is safety to update IDTR.
+  //
+  AsmReadIdtr (&Idtr);
+  Status = AsmExecute32BitCode (Function, Param1, Param2, &mGdt);
+  AsmWriteIdtr (&Idtr);
+
+  return Status;
+}
+