OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c

   1 /** @file
   2  *  PE/COFF emulator protocol implementation to start Linux kernel
   3  *  images from non-native firmware
   4  *
   5  *  Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
   6  *
   7  *  SPDX-License-Identifier: BSD-2-Clause-Patent
   8  *
   9  */
  10
  11 #include <PiDxe.h>
  12
  13 #include <Library/BaseMemoryLib.h>
  14 #include <Library/DebugLib.h>
  15 #include <Library/PeCoffLib.h>
  16 #include <Library/UefiBootServicesTableLib.h>
  17
  18 #include <Protocol/PeCoffImageEmulator.h>
  19
  20 #pragma pack (1)
  21 typedef struct {
  22   UINT8     Type;
  23   UINT8     Size;
  24   UINT16    MachineType;
  25   UINT32    EntryPoint;
  26 } PE_COMPAT_TYPE1;
  27 #pragma pack ()
  28
  29 STATIC
  30 BOOLEAN
  31 EFIAPI
  32 IsImageSupported (
  33   IN  EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL  *This,
  34   IN  UINT16                                ImageType,
  35   IN  EFI_DEVICE_PATH_PROTOCOL              *DevicePath   OPTIONAL
  36   )
  37 {
  38   return ImageType == EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION;
  39 }
  40
  41 STATIC
  42 EFI_IMAGE_ENTRY_POINT
  43 EFIAPI
  44 GetCompatEntryPoint (
  45   IN  EFI_PHYSICAL_ADDRESS  ImageBase
  46   )
  47 {
  48   EFI_IMAGE_DOS_HEADER      *DosHdr;
  49   UINTN                     PeCoffHeaderOffset;
  50   EFI_IMAGE_NT_HEADERS32    *Pe32;
  51   EFI_IMAGE_SECTION_HEADER  *Section;
  52   UINTN                     NumberOfSections;
  53   PE_COMPAT_TYPE1           *PeCompat;
  54   UINTN                     PeCompatEnd;
  55
  56   DosHdr = (EFI_IMAGE_DOS_HEADER *)(UINTN)ImageBase;
  57   if (DosHdr->e_magic != EFI_IMAGE_DOS_SIGNATURE) {
  58     return NULL;
  59   }
  60
  61   PeCoffHeaderOffset = DosHdr->e_lfanew;
  62   Pe32               = (EFI_IMAGE_NT_HEADERS32 *)((UINTN)ImageBase + PeCoffHeaderOffset);
  63
  64   Section = (EFI_IMAGE_SECTION_HEADER *)((UINTN)&Pe32->OptionalHeader +
  65                                          Pe32->FileHeader.SizeOfOptionalHeader);
  66   NumberOfSections = (UINTN)Pe32->FileHeader.NumberOfSections;
  67
  68   while (NumberOfSections--) {
  69     if (!CompareMem (Section->Name, ".compat", sizeof (Section->Name))) {
  70       //
  71       // Dereference the section contents to find the mixed mode entry point
  72       //
  73       PeCompat    = (PE_COMPAT_TYPE1 *)((UINTN)ImageBase + Section->VirtualAddress);
  74       PeCompatEnd = (UINTN)(VOID *)PeCompat + Section->Misc.VirtualSize;
  75
  76       while (PeCompat->Type != 0 && (UINTN)(VOID *)PeCompat < PeCompatEnd) {
  77         if ((PeCompat->Type == 1) &&
  78             (PeCompat->Size >= sizeof (PE_COMPAT_TYPE1)) &&
  79             EFI_IMAGE_MACHINE_TYPE_SUPPORTED (PeCompat->MachineType))
  80         {
  81           return (EFI_IMAGE_ENTRY_POINT)((UINTN)ImageBase + PeCompat->EntryPoint);
  82         }
  83
  84         PeCompat = (PE_COMPAT_TYPE1 *)((UINTN)PeCompat + PeCompat->Size);
  85         ASSERT ((UINTN)(VOID *)PeCompat < PeCompatEnd);
  86       }
  87     }
  88
  89     Section++;
  90   }
  91
  92   return NULL;
  93 }
  94
  95 STATIC
  96 EFI_STATUS
  97 EFIAPI
  98 RegisterImage (
  99   IN      EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL  *This,
 100   IN      EFI_PHYSICAL_ADDRESS                  ImageBase,
 101   IN      UINT64                                ImageSize,
 102   IN  OUT EFI_IMAGE_ENTRY_POINT                 *EntryPoint
 103   )
 104 {
 105   EFI_IMAGE_ENTRY_POINT  CompatEntryPoint;
 106
 107   CompatEntryPoint = GetCompatEntryPoint (ImageBase);
 108   if (CompatEntryPoint == NULL) {
 109     return EFI_UNSUPPORTED;
 110   }
 111
 112   *EntryPoint = CompatEntryPoint;
 113   return EFI_SUCCESS;
 114 }
 115
 116 STATIC
 117 EFI_STATUS
 118 EFIAPI
 119 UnregisterImage (
 120   IN  EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL  *This,
 121   IN  EFI_PHYSICAL_ADDRESS                  ImageBase
 122   )
 123 {
 124   return EFI_SUCCESS;
 125 }
 126
 127 STATIC EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL  mCompatLoaderPeCoffEmuProtocol = {
 128   IsImageSupported,
 129   RegisterImage,
 130   UnregisterImage,
 131   EDKII_PECOFF_IMAGE_EMULATOR_VERSION,
 132   EFI_IMAGE_MACHINE_X64
 133 };
 134
 135 EFI_STATUS
 136 EFIAPI
 137 CompatImageLoaderDxeEntryPoint (
 138   IN EFI_HANDLE        ImageHandle,
 139   IN EFI_SYSTEM_TABLE  *SystemTable
 140   )
 141 {
 142   return gBS->InstallProtocolInterface (
 143                 &ImageHandle,
 144                 &gEdkiiPeCoffImageEmulatorProtocolGuid,
 145                 EFI_NATIVE_INTERFACE,
 146                 &mCompatLoaderPeCoffEmuProtocol
 147                 );
 148 }