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
  19
  20
  21 /**
  22   Support routine for the PE/COFF Loader that reads a buffer from a PE/COFF file
  23
  24   @param  FileHandle   The handle to the PE/COFF file
  25   @param  FileOffset   The offset, in bytes, into the file to read
  26   @param  ReadSize     The number of bytes to read from the file starting at
  27                        FileOffset
  28   @param  Buffer       A pointer to the buffer to read the data into.
  29
  30   @retval EFI_SUCCESS  ReadSize bytes of data were read into Buffer from the
  31                        PE/COFF file starting at FileOffset
  32
  33 **/
  34 EFI_STATUS
  35 PeiImageRead (
  36   IN     VOID    *FileHandle,
  37   IN     UINTN   FileOffset,
  38   IN OUT UINTN   *ReadSize,
  39   OUT    VOID    *Buffer
  40   )
  41 {
  42   UINT8 *Destination32;
  43   UINT8 *Source32;
  44   UINTN  Length;
  45
  46
  47   Destination32 = Buffer;
  48   Source32      = (UINT8 *) ((UINTN) FileHandle + FileOffset);
  49
  50   //
  51   // This function assumes 32-bit alignment to increase performance
  52   //
  53 //  ASSERT (ALIGN_POINTER (Destination32, sizeof (UINT32)) == Destination32);
  54 //  ASSERT (ALIGN_POINTER (Source32, sizeof (UINT32)) == Source32);
  55
  56   Length = *ReadSize;
  57   while (Length-- != 0) {
  58     *(Destination32++) = *(Source32++);
  59   }
  60
  61   return EFI_SUCCESS;
  62 }
  63
  64
  65
  66
  67
  68 /**
  69    This function simply retrieves the function pointer of ImageRead in
  70    ImageContext structure.
  71
  72    @param ImageContext       A pointer to the structure of
  73                              PE_COFF_LOADER_IMAGE_CONTEXT
  74
  75    @retval EFI_SUCCESS       This function always return EFI_SUCCESS.
  76
  77 **/
  78 EFI_STATUS
  79 GetImageReadFunction (
  80   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  81   )
  82 {
  83   VOID        *MemoryBuffer;
  84
  85   if (gInMemory) {
  86     ImageContext->ImageRead = PeiImageRead;
  87     return EFI_SUCCESS;
  88   }
  89
  90   //
  91   // BugBug; This code assumes PeiImageRead() is less than a page in size!
  92   //  Allocate a page so we can shaddow the read function from FLASH into
  93   //  memory to increase performance.
  94   //
  95
  96   MemoryBuffer = AllocateCopyPool (0x400, (VOID *)(UINTN) PeiImageRead);
  97   ASSERT (MemoryBuffer != NULL);
  98
  99   ImageContext->ImageRead = (PE_COFF_LOADER_READ_FILE) (UINTN) MemoryBuffer;
 100
 101   return EFI_SUCCESS;
 102 }