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 EFIAPI
  36 PeiImageRead (
  37   IN     VOID    *FileHandle,
  38   IN     UINTN   FileOffset,
  39   IN OUT UINTN   *ReadSize,
  40   OUT    VOID    *Buffer
  41   )
  42 {
  43   UINT8 *Destination32;
  44   UINT8 *Source32;
  45   UINTN  Length;
  46
  47
  48   Destination32 = Buffer;
  49   Source32      = (UINT8 *) ((UINTN) FileHandle + FileOffset);
  50
  51   //
  52   // This function assumes 32-bit alignment to increase performance
  53   //
  54 //  ASSERT (ALIGN_POINTER (Destination32, sizeof (UINT32)) == Destination32);
  55 //  ASSERT (ALIGN_POINTER (Source32, sizeof (UINT32)) == Source32);
  56
  57   Length = *ReadSize;
  58   while (Length--) {
  59     *(Destination32++) = *(Source32++);
  60   }
  61
  62   return EFI_SUCCESS;
  63 }
  64
  65
  66
  67
  68
  69 /**
  70    This function simply retrieves the function pointer of ImageRead in
  71    ImageContext structure.
  72
  73    @param ImageContext       A pointer to the structure of
  74                              PE_COFF_LOADER_IMAGE_CONTEXT
  75
  76    @retval EFI_SUCCESS       This function always return EFI_SUCCESS.
  77
  78 **/
  79 EFI_STATUS
  80 GetImageReadFunction (
  81   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  82   )
  83 {
  84   VOID        *MemoryBuffer;
  85
  86   if (gInMemory) {
  87     ImageContext->ImageRead = PeiImageRead;
  88     return EFI_SUCCESS;
  89   }
  90
  91   //
  92   // BugBug; This code assumes PeiImageRead() is less than a page in size!
  93   //  Allocate a page so we can shaddow the read function from FLASH into
  94   //  memory to increase performance.
  95   //
  96
  97   MemoryBuffer = AllocateCopyPool (0x400, (VOID *)(UINTN) PeiImageRead);
  98   ASSERT (MemoryBuffer != NULL);
  99
 100   ImageContext->ImageRead = (PE_COFF_LOADER_READ_FILE) (UINTN) MemoryBuffer;
 101
 102   return EFI_SUCCESS;
 103 }