MdeModulePkg/Core/DxeIplPeim/Ia32/ImageRead.c

   1 /** @file
   2   This module loads an image to memory for IA32 Cpu architecture.
   3
   4 Copyright (c) 2006 - 2008, Intel Corporation. <BR>
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "DxeIpl.h"
  16
  17 /**
  18   Support routine for the PE/COFF Loader that reads a buffer from a PE/COFF file
  19
  20   @param  FileHandle   The handle to the PE/COFF file
  21   @param  FileOffset   The offset, in bytes, into the file to read
  22   @param  ReadSize     The number of bytes to read from the file starting at
  23                        FileOffset
  24   @param  Buffer       A pointer to the buffer to read the data into.
  25
  26   @retval EFI_SUCCESS  ReadSize bytes of data were read into Buffer from the
  27                        PE/COFF file starting at FileOffset
  28
  29 **/
  30 EFI_STATUS
  31 PeiImageRead (
  32   IN     VOID    *FileHandle,
  33   IN     UINTN   FileOffset,
  34   IN OUT UINTN   *ReadSize,
  35   OUT    VOID    *Buffer
  36   )
  37 {
  38   UINT8 *Destination32;
  39   UINT8 *Source32;
  40   UINTN  Length;
  41
  42
  43   Destination32 = Buffer;
  44   Source32      = (UINT8 *) ((UINTN) FileHandle + FileOffset);
  45
  46   //
  47   // This function assumes 32-bit alignment to increase performance
  48   //
  49
  50   Length = *ReadSize;
  51   while (Length-- != 0) {
  52     *(Destination32++) = *(Source32++);
  53   }
  54
  55   return EFI_SUCCESS;
  56 }
  57
  58
  59 /**
  60    This function simply retrieves the function pointer of ImageRead in
  61    ImageContext structure.
  62
  63    @param ImageContext       A pointer to the structure of
  64                              PE_COFF_LOADER_IMAGE_CONTEXT
  65
  66    @retval EFI_SUCCESS       This function always returns EFI_SUCCESS.
  67
  68 **/
  69 EFI_STATUS
  70 GetImageReadFunction (
  71   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  72   )
  73 {
  74   VOID        *MemoryBuffer;
  75
  76   if (gInMemory) {
  77     ImageContext->ImageRead = PeiImageRead;
  78     return EFI_SUCCESS;
  79   }
  80
  81   //
  82   // BugBug; This code assumes PeiImageRead() is less than a page in size!
  83   //  Allocate a page so we can shaddow the read function from FLASH into
  84   //  memory to increase performance.
  85   //
  86
  87   MemoryBuffer = AllocateCopyPool (0x400, (VOID *)(UINTN) PeiImageRead);
  88   ASSERT (MemoryBuffer != NULL);
  89
  90   ImageContext->ImageRead = (PE_COFF_LOADER_READ_FILE) (UINTN) MemoryBuffer;
  91
  92   return EFI_SUCCESS;
  93 }