EdkModulePkg/Core/DxeIplPeim/ia32/ImageRead.c

   1 /*++
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14   ImageRead.c
  15
  16 Abstract:
  17
  18 --*/
  19
  20 #include <DxeIpl.h>
  21
  22 EFI_STATUS
  23 EFIAPI
  24 PeiImageRead (
  25   IN     VOID    *FileHandle,
  26   IN     UINTN   FileOffset,
  27   IN OUT UINTN   *ReadSize,
  28   OUT    VOID    *Buffer
  29   )
  30 /*++
  31
  32 Routine Description:
  33
  34   Support routine for the PE/COFF Loader that reads a buffer from a PE/COFF file
  35
  36 Arguments:
  37
  38   FileHandle - The handle to the PE/COFF file
  39
  40   FileOffset - The offset, in bytes, into the file to read
  41
  42   ReadSize   - The number of bytes to read from the file starting at FileOffset
  43
  44   Buffer     - A pointer to the buffer to read the data into.
  45
  46 Returns:
  47
  48   EFI_SUCCESS - ReadSize bytes of data were read into Buffer from the PE/COFF file starting at FileOffset
  49
  50 --*/
  51 {
  52   UINT8 *Destination32;
  53   UINT8 *Source32;
  54   UINTN  Length;
  55
  56
  57   Destination32 = Buffer;
  58   Source32      = (UINT8 *) ((UINTN) FileHandle + FileOffset);
  59
  60   //
  61   // This function assumes 32-bit alignment to increase performance
  62   //
  63 //  ASSERT (ALIGN_POINTER (Destination32, sizeof (UINT32)) == Destination32);
  64 //  ASSERT (ALIGN_POINTER (Source32, sizeof (UINT32)) == Source32);
  65
  66   Length = *ReadSize;
  67   while (Length--) {
  68     *(Destination32++) = *(Source32++);
  69   }
  70
  71   return EFI_SUCCESS;
  72 }
  73
  74 EFI_STATUS
  75 GetImageReadFunction (
  76   IN      PE_COFF_LOADER_IMAGE_CONTEXT  *ImageContext
  77   )
  78 /*++
  79
  80 Routine Description:
  81   Support routine to return the PE32 Image Reader.
  82   If the PeiImageRead() function is less than a page
  83   in legnth. If the function is more than a page the DXE IPL will crash!!!!
  84
  85 Arguments:
  86   ImageContext  - The context of the image being loaded
  87
  88 Returns:
  89   EFI_SUCCESS - If Image function location is found
  90
  91 --*/
  92 {
  93   VOID        *MemoryBuffer;
  94
  95   if (gInMemory) {
  96     ImageContext->ImageRead = PeiImageRead;
  97     return EFI_SUCCESS;
  98   }
  99
 100   //
 101   // BugBug; This code assumes PeiImageRead() is less than a page in size!
 102   //  Allocate a page so we can shaddow the read function from FLASH into
 103   //  memory to increase performance.
 104   //
 105
 106   MemoryBuffer = AllocateCopyPool (0x400, (VOID *)(UINTN) PeiImageRead);
 107   ASSERT (MemoryBuffer != NULL);
 108
 109   ImageContext->ImageRead = (PE_COFF_LOADER_READ_FILE) (UINTN) MemoryBuffer;
 110
 111   return EFI_SUCCESS;
 112 }