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 EFI_STATUS
  18 EFIAPI
  19 PeiImageRead (
  20   IN     VOID    *FileHandle,
  21   IN     UINTN   FileOffset,
  22   IN OUT UINTN   *ReadSize,
  23   OUT    VOID    *Buffer
  24   )
  25 /*++
  26
  27 Routine Description:
  28
  29   Support routine for the PE/COFF Loader that reads a buffer from a PE/COFF file
  30
  31 Arguments:
  32
  33   FileHandle - The handle to the PE/COFF file
  34
  35   FileOffset - The offset, in bytes, into the file to read
  36
  37   ReadSize   - The number of bytes to read from the file starting at FileOffset
  38
  39   Buffer     - A pointer to the buffer to read the data into.
  40
  41 Returns:
  42
  43   EFI_SUCCESS - ReadSize bytes of data were read into Buffer from the PE/COFF file starting at FileOffset
  44
  45 --*/
  46 {
  47   UINT8 *Destination32;
  48   UINT8 *Source32;
  49   UINTN  Length;
  50
  51
  52   Destination32 = Buffer;
  53   Source32      = (UINT8 *) ((UINTN) FileHandle + FileOffset);
  54
  55   //
  56   // This function assumes 32-bit alignment to increase performance
  57   //
  58 //  ASSERT (ALIGN_POINTER (Destination32, sizeof (UINT32)) == Destination32);
  59 //  ASSERT (ALIGN_POINTER (Source32, sizeof (UINT32)) == Source32);
  60
  61   Length = *ReadSize;
  62   while (Length--) {
  63     *(Destination32++) = *(Source32++);
  64   }
  65
  66   return EFI_SUCCESS;
  67 }
  68
  69 EFI_STATUS
  70 GetImageReadFunction (
  71   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  72   )
  73 /*++
  74
  75 Routine Description:
  76   Support routine to return the PE32 Image Reader.
  77   If the PeiImageRead() function is less than a page
  78   in legnth. If the function is more than a page the DXE IPL will crash!!!!
  79
  80 Arguments:
  81   ImageContext  - The context of the image being loaded
  82
  83 Returns:
  84   EFI_SUCCESS - If Image function location is found
  85
  86 --*/
  87 {
  88   VOID        *MemoryBuffer;
  89
  90   if (gInMemory) {
  91     ImageContext->ImageRead = PeiImageRead;
  92     return EFI_SUCCESS;
  93   }
  94
  95   //
  96   // BugBug; This code assumes PeiImageRead() is less than a page in size!
  97   //  Allocate a page so we can shaddow the read function from FLASH into
  98   //  memory to increase performance.
  99   //
 100
 101   MemoryBuffer = AllocateCopyPool (0x400, (VOID *)(UINTN) PeiImageRead);
 102   ASSERT (MemoryBuffer != NULL);
 103
 104   ImageContext->ImageRead = (PE_COFF_LOADER_READ_FILE) (UINTN) MemoryBuffer;
 105
 106   return EFI_SUCCESS;
 107 }