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 57df17fe26
("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>
144 lines
4.0 KiB
C
144 lines
4.0 KiB
C
/** @file
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* PE/COFF emulator protocol implementation to start Linux kernel
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* images from non-native firmware
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*
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* Copyright (c) 2020, ARM Ltd. All rights reserved.<BR>
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*
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* SPDX-License-Identifier: BSD-2-Clause-Patent
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*
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*/
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#include <PiDxe.h>
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#include <Library/BaseMemoryLib.h>
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#include <Library/DebugLib.h>
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#include <Library/PeCoffLib.h>
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#include <Library/UefiBootServicesTableLib.h>
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#include <Protocol/PeCoffImageEmulator.h>
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#pragma pack (1)
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typedef struct {
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UINT8 Type;
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UINT8 Size;
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UINT16 MachineType;
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UINT32 EntryPoint;
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} PE_COMPAT_TYPE1;
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#pragma pack ()
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STATIC
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BOOLEAN
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EFIAPI
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IsImageSupported (
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IN EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL *This,
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IN UINT16 ImageType,
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IN EFI_DEVICE_PATH_PROTOCOL *DevicePath OPTIONAL
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)
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{
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return ImageType == EFI_IMAGE_SUBSYSTEM_EFI_APPLICATION;
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}
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STATIC
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EFI_IMAGE_ENTRY_POINT
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EFIAPI
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GetCompatEntryPoint (
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IN EFI_PHYSICAL_ADDRESS ImageBase
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)
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{
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EFI_IMAGE_DOS_HEADER *DosHdr;
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UINTN PeCoffHeaderOffset;
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EFI_IMAGE_NT_HEADERS32 *Pe32;
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EFI_IMAGE_SECTION_HEADER *Section;
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UINTN NumberOfSections;
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PE_COMPAT_TYPE1 *PeCompat;
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UINTN PeCompatEnd;
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DosHdr = (EFI_IMAGE_DOS_HEADER *)(UINTN)ImageBase;
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if (DosHdr->e_magic != EFI_IMAGE_DOS_SIGNATURE) {
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return NULL;
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}
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PeCoffHeaderOffset = DosHdr->e_lfanew;
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Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINTN)ImageBase + PeCoffHeaderOffset);
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Section = (EFI_IMAGE_SECTION_HEADER *)((UINTN)&Pe32->OptionalHeader +
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Pe32->FileHeader.SizeOfOptionalHeader);
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NumberOfSections = (UINTN)Pe32->FileHeader.NumberOfSections;
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while (NumberOfSections--) {
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if (!CompareMem (Section->Name, ".compat", sizeof (Section->Name))) {
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//
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// Dereference the section contents to find the mixed mode entry point
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//
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PeCompat = (PE_COMPAT_TYPE1 *)((UINTN)ImageBase + Section->VirtualAddress);
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PeCompatEnd = (UINTN)(VOID *)PeCompat + Section->Misc.VirtualSize;
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while (PeCompat->Type != 0 && (UINTN)(VOID *)PeCompat < PeCompatEnd) {
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if (PeCompat->Type == 1 &&
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PeCompat->Size >= sizeof (PE_COMPAT_TYPE1) &&
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EFI_IMAGE_MACHINE_TYPE_SUPPORTED (PeCompat->MachineType)) {
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return (EFI_IMAGE_ENTRY_POINT)((UINTN)ImageBase + PeCompat->EntryPoint);
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}
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PeCompat = (PE_COMPAT_TYPE1 *)((UINTN)PeCompat + PeCompat->Size);
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ASSERT ((UINTN)(VOID *)PeCompat < PeCompatEnd);
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}
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}
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Section++;
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}
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return NULL;
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}
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STATIC
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EFI_STATUS
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EFIAPI
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RegisterImage (
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IN EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL *This,
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IN EFI_PHYSICAL_ADDRESS ImageBase,
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IN UINT64 ImageSize,
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IN OUT EFI_IMAGE_ENTRY_POINT *EntryPoint
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)
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{
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EFI_IMAGE_ENTRY_POINT CompatEntryPoint;
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CompatEntryPoint = GetCompatEntryPoint (ImageBase);
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if (CompatEntryPoint == NULL) {
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return EFI_UNSUPPORTED;
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}
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*EntryPoint = CompatEntryPoint;
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return EFI_SUCCESS;
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}
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STATIC
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EFI_STATUS
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EFIAPI
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UnregisterImage (
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IN EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL *This,
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IN EFI_PHYSICAL_ADDRESS ImageBase
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)
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{
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return EFI_SUCCESS;
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}
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STATIC EDKII_PECOFF_IMAGE_EMULATOR_PROTOCOL mCompatLoaderPeCoffEmuProtocol = {
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IsImageSupported,
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RegisterImage,
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UnregisterImage,
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EDKII_PECOFF_IMAGE_EMULATOR_VERSION,
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EFI_IMAGE_MACHINE_X64
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};
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EFI_STATUS
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EFIAPI
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CompatImageLoaderDxeEntryPoint (
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IN EFI_HANDLE ImageHandle,
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IN EFI_SYSTEM_TABLE *SystemTable
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)
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{
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return gBS->InstallProtocolInterface (&ImageHandle,
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&gEdkiiPeCoffImageEmulatorProtocolGuid,
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EFI_NATIVE_INTERFACE,
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&mCompatLoaderPeCoffEmuProtocol);
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}
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