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).
Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c | 140
++++++++++++++++++++
OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf | 36 +++++
OvmfPkg/OvmfPkgIa32.dsc | 5 +
OvmfPkg/OvmfPkgIa32.fdf | 4 +
4 files changed, 185 insertions(+)
diff --git a/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c
b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c
new file mode 100644
index 000000000000..d2ae03eabf7f
--- /dev/null
+++ b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.c
@@ -0,0 +1,140 @@
+/** @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/PeCoffLib.h>
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiDriverEntryPoint.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;
+
+ 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);
+
+ while (PeCompat->Type != 0) {
+ 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);
+ }
+ }
+ 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 000000000000..82369384fbe6
--- /dev/null
+++ b/OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf
@@ -0,0 +1,36 @@
+## @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
+ PeCoffLib
+ UefiBootServicesTableLib
+ UefiDriverEntryPoint
+
+[Protocols]
+ gEdkiiPeCoffImageEmulatorProtocolGuid ## PRODUCES
+
+[Depex]
+ TRUE
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index 870eb7aa7429..a996c0a7a7c9 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -33,6 +33,7 @@ [Defines]
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 @@ [Components]
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 b6cd5da4f2b3..ff8d80859fb9 100644
--- a/OvmfPkg/OvmfPkgIa32.fdf
+++ b/OvmfPkg/OvmfPkgIa32.fdf
@@ -354,6 +354,10 @@ [FV.DXEFV]
!endif
!endif
+!if $(LOAD_X64_ON_IA32_ENABLE) == TRUE
+INF OvmfPkg/CompatImageLoaderDxe/CompatImageLoaderDxe.inf
+!endif
+
################################################################################
[FV.FVMAIN_COMPACT]
--
2.17.1
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