ArmPlatformPkg/FileSystem/BootMonFs/BootMonFsImages.c

   1 /** @file
   2 *
   3 *  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
   4 *
   5 *  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 <Library/IoLib.h>
  16 #include <Library/NorFlashPlatformLib.h>
  17 #include <Library/BaseMemoryLib.h>
  18 #include <Library/MemoryAllocationLib.h>
  19
  20 #include <Protocol/SimpleFileSystem.h>
  21
  22 #include "BootMonFsInternal.h"
  23
  24 UINT32
  25 BootMonFsChecksum (
  26   IN VOID   *Data,
  27   IN UINT32 Size
  28   )
  29 {
  30   UINT32  *Ptr;
  31   UINT32  Word;
  32   UINT32  Checksum;
  33
  34   ASSERT (Size % 4 == 0);
  35
  36   Checksum = 0;
  37   Ptr = (UINT32*)Data;
  38
  39   while (Size > 0) {
  40     Word = *Ptr++;
  41     Size -= 4;
  42
  43     if (Word > ~Checksum) {
  44       Checksum++;
  45     }
  46
  47     Checksum += Word;
  48   }
  49
  50   return ~Checksum;
  51 }
  52
  53 EFI_STATUS
  54 BootMonFsComputeFooterChecksum (
  55   IN OUT HW_IMAGE_DESCRIPTION *Footer
  56   )
  57 {
  58   HW_IMAGE_DESCRIPTION *Description;
  59   UINT32                Index;
  60
  61   Footer->Attributes = 1;
  62
  63   Description = AllocateZeroPool (sizeof (HW_IMAGE_DESCRIPTION));
  64   if (Description == NULL) {
  65     DEBUG ((DEBUG_ERROR, "BootMonFsComputeFooterChecksum: Unable to allocate memory.\n"));
  66     return EFI_OUT_OF_RESOURCES;
  67   }
  68
  69   // Copy over to temporary shim
  70   CopyMem (Description, Footer, sizeof (HW_IMAGE_DESCRIPTION));
  71
  72   // BootMon doesn't checksum the previous checksum
  73   Description->FooterChecksum = 0;
  74
  75   // Blank out regions which aren't being used.
  76   for (Index = Footer->RegionCount; Index < HW_IMAGE_DESCRIPTION_REGION_MAX; Index++) {
  77     Description->Region[Index].Checksum = 0;
  78     Description->Region[Index].LoadAddress = 0;
  79     Description->Region[Index].Offset = 0;
  80     Description->Region[Index].Size = 0;
  81   }
  82
  83   // Compute the checksum
  84   Footer->FooterChecksum = BootMonFsChecksum (Description, sizeof (HW_IMAGE_DESCRIPTION));
  85
  86   FreePool (Description);
  87
  88   return EFI_SUCCESS;
  89 }
  90
  91 BOOLEAN
  92 BootMonFsIsImageValid (
  93   IN HW_IMAGE_DESCRIPTION  *Desc,
  94   IN EFI_LBA                Lba
  95   )
  96 {
  97   EFI_STATUS            Status;
  98   HW_IMAGE_FOOTER      *Footer;
  99   UINT32                Checksum;
 100
 101   Footer = &Desc->Footer;
 102
 103   // Check that the verification bytes are present
 104   if ((Footer->FooterSignature1 != HW_IMAGE_FOOTER_SIGNATURE_1) ||
 105       (Footer->FooterSignature2 != HW_IMAGE_FOOTER_SIGNATURE_2)) {
 106     return FALSE;
 107   }
 108
 109   if (Footer->Version == HW_IMAGE_FOOTER_VERSION) {
 110     if (Footer->Offset != HW_IMAGE_FOOTER_OFFSET) {
 111       return FALSE;
 112     }
 113   } else if (Footer->Version == HW_IMAGE_FOOTER_VERSION2) {
 114     if (Footer->Offset != HW_IMAGE_FOOTER_OFFSET2) {
 115       return FALSE;
 116     }
 117   } else {
 118     return FALSE;
 119   }
 120
 121   Checksum = Desc->FooterChecksum;
 122   Status = BootMonFsComputeFooterChecksum (Desc);
 123   if (EFI_ERROR (Status)) {
 124     DEBUG ((DEBUG_ERROR, "Warning: failed to compute checksum for image '%a'\n", Desc->Footer.Filename));
 125   }
 126
 127   if (Desc->FooterChecksum != Checksum) {
 128     DEBUG ((DEBUG_ERROR, "Warning: image '%a' checksum mismatch.\n", Desc->Footer.Filename));
 129   }
 130
 131   if ((Desc->BlockEnd != Lba) || (Desc->BlockStart > Desc->BlockEnd)) {
 132     return FALSE;
 133   }
 134
 135   return TRUE;
 136 }
 137
 138 EFI_STATUS
 139 BootMonFsDiscoverNextImage (
 140   IN BOOTMON_FS_INSTANCE      *Instance,
 141   IN EFI_LBA                  *LbaStart,
 142   OUT HW_IMAGE_DESCRIPTION    *ImageDescription
 143   )
 144 {
 145   EFI_DISK_IO_PROTOCOL  *DiskIo;
 146   EFI_LBA                CurrentLba;
 147   UINT64                 DescOffset;
 148   EFI_STATUS             Status;
 149
 150   DiskIo = Instance->DiskIo;
 151
 152   CurrentLba = *LbaStart;
 153
 154   // Look for images in the rest of this block
 155   while (CurrentLba <= Instance->Media->LastBlock) {
 156     // Work out the byte offset into media of the image description in this block
 157     // If present, the image description is at the very end of the block.
 158     DescOffset = ((CurrentLba + 1) * Instance->Media->BlockSize) - sizeof (HW_IMAGE_DESCRIPTION);
 159
 160     // Read the image description from media
 161     Status = DiskIo->ReadDisk (DiskIo,
 162                        Instance->Media->MediaId,
 163                        DescOffset,
 164                        sizeof (HW_IMAGE_DESCRIPTION),
 165                        ImageDescription
 166                        );
 167     if (EFI_ERROR (Status)) {
 168       return Status;
 169     }
 170
 171     // If we found a valid image description...
 172     if (BootMonFsIsImageValid (ImageDescription, (CurrentLba - Instance->Media->LowestAlignedLba))) {
 173       DEBUG ((EFI_D_ERROR, "Found image: %a in block %d.\n", &(ImageDescription->Footer.Filename), (UINTN)(CurrentLba - Instance->Media->LowestAlignedLba)));
 174
 175       *LbaStart = ImageDescription->BlockEnd + 1;
 176       return EFI_SUCCESS;
 177     } else {
 178       CurrentLba++;
 179     }
 180   }
 181
 182   *LbaStart = CurrentLba;
 183   return EFI_NOT_FOUND;
 184 }
 185
 186 EFI_STATUS
 187 BootMonFsInitialize (
 188   IN BOOTMON_FS_INSTANCE *Instance
 189   )
 190 {
 191   EFI_STATUS               Status;
 192   EFI_LBA                  Lba;
 193   UINT32                   ImageCount;
 194   BOOTMON_FS_FILE          *NewFile;
 195
 196   ImageCount = 0;
 197   Lba = 0;
 198
 199   while (1) {
 200     Status = BootMonFsCreateFile (Instance, &NewFile);
 201     if (EFI_ERROR (Status)) {
 202       return Status;
 203     }
 204
 205     Status = BootMonFsDiscoverNextImage (Instance, &Lba, &(NewFile->HwDescription));
 206     if (EFI_ERROR (Status)) {
 207       // Free NewFile allocated by BootMonFsCreateFile ()
 208       FreePool (NewFile);
 209       break;
 210     }
 211     InsertTailList (&Instance->RootFile->Link, &NewFile->Link);
 212     ImageCount++;
 213   }
 214
 215   Instance->Initialized = TRUE;
 216   return EFI_SUCCESS;
 217 }