OvmfPkg IA32: add support for loading X64 images

This is the UEFI counterpart to my Linux series which generalizes
mixed mode support into a feature that requires very little internal
knowledge about the architecture specifics of booting Linux on the
part of the bootloader or firmware.

Instead, we add a .compat PE/COFF header containing an array of
PE_COMPAT nodes containing <machine type, entrypoint> tuples that
describe alternate entrypoints into the image for different native
machine types, e.g., IA-32 in a 64-bit image so it can be booted
from IA-32 firmware.

This patch implements the PE/COFF emulator protocol to take this new
section into account, so that such images can simply be loaded via
LoadImage/StartImage, e.g., straight from the shell.

This feature is based on the EDK2 specific PE/COFF emulator protocol
that was introduced in commit 57df17fe26cd ("MdeModulePkg/DxeCore:
invoke the emulator protocol for foreign images", 2019-04-14).

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2564
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>

4 files changed, 189 insertions, 0 deletions

diff --git a/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c
new file mode 100644
index 0000000000..41ddfbc517
--- /dev/null
+++ b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c
@@ -0,0 +1,143 @@
+/** @file

+ *  PE/COFF emulator protocol implementation to start Linux kernel

+ *  images from non-native firmware

+ *

+ *  Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>

+ *

+ *  SPDX-License-Identifier: BSD-2-Clause-Patent

+ *

+ */

+

+#include <PiDxe.h>

+

+#include <Library/BaseMemoryLib.h>

+#include <Library/DebugLib.h>

+#include <Library/PeCoffLib.h>

+#include <Library/UefiBootServicesTableLib.h>

+

+#include <Protocol/PeCoffImageEmulator.h>

+

+#pragma pack (1)

+typedef struct {

+  UINT8   Type;

+  UINT8   Size;

+  UINT16  MachineType;

+  UINT32  EntryPoint;

+} PE_COMPAT_TYPE1;

+#pragma pack ()

+

+STATIC

+BOOLEAN

+EFIAPI

+IsImageSupported (

+  IN  EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL    *This,

+  IN  UINT16                                  ImageType,

+  IN  EFI_DEVICE_PATH_PROTOCOL                *DevicePath   OPTIONAL

+  )

+{

+  return ImageType == EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION;

+}

+

+STATIC

+EFI_IMAGE_ENTRY_POINT

+EFIAPI

+GetCompatEntryPoint (

+  IN  EFI_PHYSICAL_ADDRESS              ImageBase

+  )

+{

+  EFI_IMAGE_DOS_HEADER                  *DosHdr;

+  UINTN                                 PeCoffHeaderOffset;

+  EFI_IMAGE_NT_HEADERS32                *Pe32;

+  EFI_IMAGE_SECTION_HEADER              *Section;

+  UINTN                                 NumberOfSections;

+  PE_COMPAT_TYPE1                       *PeCompat;

+  UINTN                                 PeCompatEnd;

+

+  DosHdr = (EFI_IMAGE_DOS_HEADER *)(UINTN)ImageBase;

+  if (DosHdr->e_magic != EFI_IMAGE_DOS_SIGNATURE) {

+    return NULL;

+  }

+

+  PeCoffHeaderOffset = DosHdr->e_lfanew;

+  Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN)ImageBase + PeCoffHeaderOffset);

+

+  Section = (EFI_IMAGE_SECTION_HEADER *)((UINTN)&Pe32->OptionalHeader +

+                                         Pe32->FileHeader.SizeOfOptionalHeader);

+  NumberOfSections = (UINTN)Pe32->FileHeader.NumberOfSections;

+

+  while (NumberOfSections--) {

+    if (!CompareMem (Section->Name, ".compat", sizeof (Section->Name))) {

+      //

+      // Dereference the section contents to find the mixed mode entry point

+      //

+      PeCompat = (PE_COMPAT_TYPE1 *)((UINTN)ImageBase + Section->VirtualAddress);

+      PeCompatEnd = (UINTN)(VOID *)PeCompat + Section->Misc.VirtualSize;

+

+      while (PeCompat->Type != 0 && (UINTN)(VOID *)PeCompat < PeCompatEnd) {

+        if (PeCompat->Type == 1 &&

+            PeCompat->Size >= sizeof (PE_COMPAT_TYPE1) &&

+            EFI_IMAGE_MACHINE_TYPE_SUPPORTED (PeCompat->MachineType)) {

+

+          return (EFI_IMAGE_ENTRY_POINT)((UINTN)ImageBase + PeCompat->EntryPoint);

+        }

+        PeCompat = (PE_COMPAT_TYPE1 *)((UINTN)PeCompat + PeCompat->Size);

+        ASSERT ((UINTN)(VOID *)PeCompat < PeCompatEnd);

+      }

+    }

+    Section++;

+  }

+  return NULL;

+}

+

+STATIC

+EFI_STATUS

+EFIAPI

+RegisterImage (

+  IN      EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL    *This,

+  IN      EFI_PHYSICAL_ADDRESS                    ImageBase,

+  IN      UINT64                                  ImageSize,

+  IN  OUT EFI_IMAGE_ENTRY_POINT                   *EntryPoint

+  )

+{

+  EFI_IMAGE_ENTRY_POINT                           CompatEntryPoint;

+

+  CompatEntryPoint = GetCompatEntryPoint (ImageBase);

+  if (CompatEntryPoint == NULL) {

+    return EFI_UNSUPPORTED;

+  }

+

+  *EntryPoint = CompatEntryPoint;

+  return EFI_SUCCESS;

+}

+

+STATIC

+EFI_STATUS

+EFIAPI

+UnregisterImage (

+  IN  EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL    *This,

+  IN  EFI_PHYSICAL_ADDRESS                    ImageBase

+  )

+{

+  return EFI_SUCCESS;

+}

+

+STATIC EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL mCompatLoaderPeCoffEmuProtocol = {

+  IsImageSupported,

+  RegisterImage,

+  UnregisterImage,

+  EDKII_PECOFF_IMAGE_EMULATOR_VERSION,

+  EFI_IMAGE_MACHINE_X64

+};

+

+EFI_STATUS

+EFIAPI

+CompatImageLoaderDxeEntryPoint (

+  IN EFI_HANDLE        ImageHandle,

+  IN EFI_SYSTEM_TABLE  *SystemTable

+  )

+{

+  return gBS->InstallProtocolInterface (&ImageHandle,

+                &gEdkiiPeCoffImageEmulatorProtocolGuid,

+                EFI_NATIVE_INTERFACE,

+                &mCompatLoaderPeCoffEmuProtocol);

+}

diff --git a/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf
new file mode 100644
index 0000000000..74f06c64bf
--- /dev/null
+++ b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf
@@ -0,0 +1,37 @@
+## @file

+#  PE/COFF emulator protocol implementation to start Linux kernel

+#  images from non-native firmware

+#

+#  Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>

+#

+#  SPDX-License-Identifier: BSD-2-Clause-Patent

+#

+##

+

+[Defines]

+  INF_VERSION                    = 1.27

+  BASE_NAME                      = CompatImageLoaderDxe

+  FILE_GUID                      = 1019f54a-2560-41b2-87b0-6750b98f3eff

+  MODULE_TYPE                    = DXE_DRIVER

+  VERSION_STRING                 = 1.0

+  ENTRY_POINT                    = CompatImageLoaderDxeEntryPoint

+

+[Sources]

+  CompatImageLoaderDxe.c

+

+[Packages]

+  MdePkg/MdePkg.dec

+  MdeModulePkg/MdeModulePkg.dec

+

+[LibraryClasses]

+  BaseMemoryLib

+  DebugLib

+  PeCoffLib

+  UefiBootServicesTableLib

+  UefiDriverEntryPoint

+

+[Protocols]

+  gEdkiiPeCoffImageEmulatorProtocolGuid   ## PRODUCES

+

+[Depex]

+  TRUE

diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 76e52a3de1..8d91903f8b 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -33,6 +33,7 @@
   DEFINE SOURCE_DEBUG_ENABLE     = FALSE

   DEFINE TPM2_ENABLE             = FALSE

   DEFINE TPM2_CONFIG_ENABLE      = FALSE

+  DEFINE LOAD_X64_ON_IA32_ENABLE = FALSE

 

   #

   # Network definition

@@ -932,3 +933,7 @@
   SecurityPkg/Tcg/Tcg2Config/Tcg2ConfigDxe.inf

 !endif

 !endif

+

+!if $(LOAD_X64_ON_IA32_ENABLE) == TRUE

+  OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf

+!endif

diff --git a/OvmfPkg/OvmfPkgIa32.fdf b/OvmfPkg/OvmfPkgIa32.fdf
index 6c342823d2..f57de4a26f 100644
--- a/OvmfPkg/OvmfPkgIa32.fdf
+++ b/OvmfPkg/OvmfPkgIa32.fdf
@@ -354,6 +354,10 @@ INF  SecurityPkg/Tcg/Tcg2Config/Tcg2ConfigDxe.inf
 !endif

 !endif

 

+!if $(LOAD_X64_ON_IA32_ENABLE) == TRUE

+INF  OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf

+!endif

+

 ################################################################################

 

 [FV.FVMAIN_COMPACT]