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 BootMonFsImageInThisBlock (
  93   IN  VOID                  *Buf,
  94   IN  UINTN                  Size,
  95   IN  UINT32                 Block,
  96   OUT HW_IMAGE_DESCRIPTION  *Image
  97   )
  98 {
  99   EFI_STATUS            Status;
 100   HW_IMAGE_FOOTER      *Ptr;
 101   HW_IMAGE_DESCRIPTION *Footer;
 102   UINT32                Checksum;
 103
 104   // The footer is stored as the last thing in the block
 105   Ptr = (HW_IMAGE_FOOTER *)((UINT8 *)Buf + Size - sizeof (HW_IMAGE_FOOTER));
 106
 107   // Check that the verification bytes are present
 108   if ((Ptr->FooterSignature1 != HW_IMAGE_FOOTER_SIGNATURE_1) || (Ptr->FooterSignature2 != HW_IMAGE_FOOTER_SIGNATURE_2)) {
 109     return FALSE;
 110   }
 111
 112   if (Ptr->Version != HW_IMAGE_FOOTER_VERSION) {
 113     return FALSE;
 114   }
 115
 116   if (Ptr->Offset != HW_IMAGE_FOOTER_OFFSET) {
 117     return FALSE;
 118   }
 119
 120   Footer = (HW_IMAGE_DESCRIPTION *)(((UINT8 *)Buf + Size - sizeof (HW_IMAGE_DESCRIPTION)));
 121   Checksum = Footer->FooterChecksum;
 122   Status = BootMonFsComputeFooterChecksum (Footer);
 123   if (EFI_ERROR (Status)) {
 124     DEBUG ((DEBUG_ERROR, "Warning: failed to compute checksum for image '%a'\n", Footer->Footer.Filename));
 125   }
 126
 127   if (Footer->FooterChecksum != Checksum) {
 128     DEBUG ((DEBUG_ERROR, "Warning: image '%a' checksum mismatch.\n", Footer->Footer.Filename));
 129   }
 130
 131   if ((Footer->BlockEnd != Block) || (Footer->BlockStart > Footer->BlockEnd)) {
 132     return FALSE;
 133   }
 134
 135   // Copy the image out
 136   CopyMem (Image, Footer, sizeof (HW_IMAGE_DESCRIPTION));
 137
 138   return TRUE;
 139 }
 140
 141 EFI_STATUS
 142 BootMonFsDiscoverNextImage (
 143   IN BOOTMON_FS_INSTANCE      *Instance,
 144   IN EFI_LBA                  *LbaStart,
 145   OUT HW_IMAGE_DESCRIPTION    *Image
 146   )
 147 {
 148   EFI_BLOCK_IO_PROTOCOL *Blocks;
 149   EFI_LBA                CurrentLba;
 150   VOID                  *Out;
 151
 152   Blocks = Instance->BlockIo;
 153
 154   // Allocate an output buffer
 155   Out = AllocatePool (Instance->Media->BlockSize);
 156   if (Out == NULL) {
 157     return EFI_OUT_OF_RESOURCES;
 158   }
 159
 160   Blocks->Reset (Blocks, FALSE);
 161   CurrentLba = *LbaStart;
 162
 163   // Look for images in the rest of this block
 164   while (CurrentLba <= Instance->Media->LastBlock) {
 165     // Read in the next block
 166     Blocks->ReadBlocks (Blocks, Instance->Media->MediaId, CurrentLba, Instance->Media->BlockSize, Out);
 167     // Check for an image in the current block
 168     if (BootMonFsImageInThisBlock (Out, Instance->Media->BlockSize, (CurrentLba - Instance->Media->LowestAlignedLba), Image)) {
 169       DEBUG ((EFI_D_ERROR, "Found image: %a in block %d.\n", &(Image->Footer.Filename), (UINTN)(CurrentLba - Instance->Media->LowestAlignedLba)));
 170       FreePool (Out);
 171       *LbaStart = Image->BlockEnd + 1;
 172       return EFI_SUCCESS;
 173     } else {
 174       CurrentLba++;
 175     }
 176   }
 177
 178   *LbaStart = CurrentLba;
 179   FreePool (Out);
 180   return EFI_NOT_FOUND;
 181 }
 182
 183 EFI_STATUS
 184 BootMonFsInitialize (
 185   IN BOOTMON_FS_INSTANCE *Instance
 186   )
 187 {
 188   EFI_STATUS               Status;
 189   EFI_LBA                  Lba;
 190   UINT32                   ImageCount;
 191   BOOTMON_FS_FILE          *NewFile;
 192
 193   ImageCount = 0;
 194   Lba = 0;
 195
 196   while (1) {
 197     Status = BootMonFsCreateFile (Instance, &NewFile);
 198     if (EFI_ERROR (Status)) {
 199       return Status;
 200     }
 201
 202     Status = BootMonFsDiscoverNextImage (Instance, &Lba, &(NewFile->HwDescription));
 203     if (EFI_ERROR (Status)) {
 204       // Free NewFile allocated by BootMonFsCreateFile ()
 205       FreePool (NewFile);
 206       break;
 207     }
 208     InsertTailList (&Instance->RootFile->Link, &NewFile->Link);
 209     ImageCount++;
 210   }
 211
 212   Instance->Initialized = TRUE;
 213   return EFI_SUCCESS;
 214 }