Change name.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5977 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 245 insertions, 0 deletions

diff --git a/MdePkg/Library/BaseLib/X86Thunk.c b/MdePkg/Library/BaseLib/X86Thunk.c
new file mode 100644
index 0000000000..c982ee3e06
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X86Thunk.c
@@ -0,0 +1,245 @@
+/** @file

+  Real Mode Thunk Functions for IA32 and X64.

+

+  Copyright (c) 2006, Intel Corporation<BR>

+  All rights reserved. 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 <BaseLibInternals.h>

+

+

+//

+// Byte packed structure for a segment descriptor in a GDT/LDT

+//

+typedef union {

+  struct {

+    UINT32  LimitLow:16;

+    UINT32  BaseLow:16;

+    UINT32  BaseMid:8;

+    UINT32  Type:4;

+    UINT32  S:1;

+    UINT32  DPL:2;

+    UINT32  P:1;

+    UINT32  LimitHigh:4;

+    UINT32  AVL:1;

+    UINT32  L:1;

+    UINT32  DB:1;

+    UINT32  G:1;

+    UINT32  BaseHigh:8;

+  } Bits;

+  UINT64  Uint64;

+} IA32_SEGMENT_DESCRIPTOR;

+

+extern CONST UINT8                  m16Start;

+extern CONST UINT16                 m16Size;

+extern CONST UINT16                 mThunk16Attr;

+extern CONST UINT16                 m16Gdt;

+extern CONST UINT16                 m16GdtrBase;

+extern CONST UINT16                 mTransition;

+

+/**

+  Invokes 16-bit code in big real mode and returns the updated register set.

+

+  This function transfers control to the 16-bit code specified by CS:EIP using

+  the stack specified by SS:ESP in RegisterSet. The updated registers are saved

+  on the real mode stack and the starting address of the save area is returned.

+

+  @param  RegisterSet Values of registers before invocation of 16-bit code.

+  @param  Transition  Pointer to the transition code under 1MB.

+

+  @return The pointer to a IA32_REGISTER_SET structure containing the updated

+          register values.

+

+**/

+IA32_REGISTER_SET *

+EFIAPI

+InternalAsmThunk16 (

+  IN      IA32_REGISTER_SET         *RegisterSet,

+  IN OUT  VOID                      *Transition

+  );

+

+/**

+  Retrieves the properties for 16-bit thunk functions.

+

+  Computes the size of the buffer and stack below 1MB required to use the

+  AsmPrepareThunk16(), AsmThunk16() and AsmPrepareAndThunk16() functions. This

+  buffer size is returned in RealModeBufferSize, and the stack size is returned

+  in ExtraStackSize. If parameters are passed to the 16-bit real mode code,

+  then the actual minimum stack size is ExtraStackSize plus the maximum number

+  of bytes that need to be passed to the 16-bit real mode code.

+

+  If RealModeBufferSize is NULL, then ASSERT().

+  If ExtraStackSize is NULL, then ASSERT().

+

+  @param  RealModeBufferSize  A pointer to the size of the buffer below 1MB

+                              required to use the 16-bit thunk functions.

+  @param  ExtraStackSize      A pointer to the extra size of stack below 1MB

+                              that the 16-bit thunk functions require for

+                              temporary storage in the transition to and from

+                              16-bit real mode.

+

+**/

+VOID

+EFIAPI

+AsmGetThunk16Properties (

+  OUT     UINT32                    *RealModeBufferSize,

+  OUT     UINT32                    *ExtraStackSize

+  )

+{

+  ASSERT (RealModeBufferSize != NULL);

+  ASSERT (ExtraStackSize != NULL);

+

+  *RealModeBufferSize = m16Size;

+

+  //

+  // Extra 4 bytes for return address, and another 4 bytes for mode transition

+  //

+  *ExtraStackSize = sizeof (IA32_DWORD_REGS) + 8;

+}

+

+/**

+  Prepares all structures a code required to use AsmThunk16().

+

+  Prepares all structures and code required to use AsmThunk16().

+

+  If ThunkContext is NULL, then ASSERT().

+

+  @param  ThunkContext  A pointer to the context structure that describes the

+                        16-bit real mode code to call.

+

+**/

+VOID

+EFIAPI

+AsmPrepareThunk16 (

+  OUT     THUNK_CONTEXT             *ThunkContext

+  )

+{

+  IA32_SEGMENT_DESCRIPTOR           *RealModeGdt;

+

+  ASSERT (ThunkContext != NULL);

+  ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);

+  ASSERT (ThunkContext->RealModeBufferSize >= m16Size);

+  ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);

+

+  CopyMem (ThunkContext->RealModeBuffer, &m16Start, m16Size);

+

+  //

+  // Point RealModeGdt to the GDT to be used in transition

+  //

+  // RealModeGdt[0]: Reserved as NULL descriptor

+  // RealModeGdt[1]: Code Segment

+  // RealModeGdt[2]: Data Segment

+  // RealModeGdt[3]: Call Gate

+  //

+  RealModeGdt = (IA32_SEGMENT_DESCRIPTOR*)(

+                  (UINTN)ThunkContext->RealModeBuffer + m16Gdt);

+

+  //

+  // Update Code & Data Segment Descriptor

+  //

+  RealModeGdt[1].Bits.BaseLow =

+    (UINT32)(UINTN)ThunkContext->RealModeBuffer & ~0xf;

+  RealModeGdt[1].Bits.BaseMid =

+    (UINT32)(UINTN)ThunkContext->RealModeBuffer >> 16;

+

+  //

+  // Update transition code entry point offset

+  //

+  *(UINT32*)((UINTN)ThunkContext->RealModeBuffer + mTransition) +=

+    (UINT32)(UINTN)ThunkContext->RealModeBuffer & 0xf;

+

+  //

+  // Update Segment Limits for both Code and Data Segment Descriptors

+  //

+  if ((ThunkContext->ThunkAttributes & THUNK_ATTRIBUTE_BIG_REAL_MODE) == 0) {

+    //

+    // Set segment limits to 64KB

+    //

+    RealModeGdt[1].Bits.LimitHigh = 0;

+    RealModeGdt[1].Bits.G = 0;

+    RealModeGdt[2].Bits.LimitHigh = 0;

+    RealModeGdt[2].Bits.G = 0;

+  }

+

+  //

+  // Update GDTBASE for this thunk context

+  //

+  *(VOID**)((UINTN)ThunkContext->RealModeBuffer + m16GdtrBase) = RealModeGdt;

+

+  //

+  // Update Thunk Attributes

+  //

+  *(UINT32*)((UINTN)ThunkContext->RealModeBuffer + mThunk16Attr) =

+    ThunkContext->ThunkAttributes;

+}

+

+/**

+  Transfers control to a 16-bit real mode entry point and returns the results.

+

+  Transfers control to a 16-bit real mode entry point and returns the results.

+  AsmPrepareThunk16() must be called with ThunkContext before this function is

+  used. This function must be called with interrupts disabled.

+

+  If ThunkContext is NULL, then ASSERT().

+  If AsmPrepareThunk16() was not previously called with ThunkContext, then ASSERT().

+

+  @param  ThunkContext  A pointer to the context structure that describes the

+                        16-bit real mode code to call.

+

+**/

+VOID

+EFIAPI

+AsmThunk16 (

+  IN OUT  THUNK_CONTEXT             *ThunkContext

+  )

+{

+  IA32_REGISTER_SET                 *UpdatedRegs;

+

+  ASSERT (ThunkContext != NULL);

+  ASSERT ((UINTN)ThunkContext->RealModeBuffer < 0x100000);

+  ASSERT (ThunkContext->RealModeBufferSize >= m16Size);

+  ASSERT ((UINTN)ThunkContext->RealModeBuffer + m16Size <= 0x100000);

+

+  UpdatedRegs = InternalAsmThunk16 (

+                  ThunkContext->RealModeState,

+                  ThunkContext->RealModeBuffer

+                  );

+

+  CopyMem (ThunkContext->RealModeState, UpdatedRegs, sizeof (*UpdatedRegs));

+}

+

+/**

+  Prepares all structures and code for a 16-bit real mode thunk, transfers

+  control to a 16-bit real mode entry point, and returns the results.

+

+  Prepares all structures and code for a 16-bit real mode thunk, transfers

+  control to a 16-bit real mode entry point, and returns the results. If the

+  caller only need to perform a single 16-bit real mode thunk, then this

+  service should be used. If the caller intends to make more than one 16-bit

+  real mode thunk, then it is more efficient if AsmPrepareThunk16() is called

+  once and AsmThunk16() can be called for each 16-bit real mode thunk. This

+  function must be called with interrupts disabled.

+

+  If ThunkContext is NULL, then ASSERT().

+

+  @param  ThunkContext  A pointer to the context structure that describes the

+                        16-bit real mode code to call.

+

+**/

+VOID

+EFIAPI

+AsmPrepareAndThunk16 (

+  IN OUT  THUNK_CONTEXT             *ThunkContext

+  )

+{

+  AsmPrepareThunk16 (ThunkContext);

+  AsmThunk16 (ThunkContext);

+}