[U-Boot] [PATCH 3/9] efi_loader: Add PE image loader

[Alexander Graf <agraf@suse.de>]

On 26.12.15 17:26, Leif Lindholm wrote:
> On Tue, Dec 22, 2015 at 02:57:50PM +0100, Alexander Graf wrote:
>> EFI uses the PE binary format for its application images. Add support to EFI PE
>> binaries as well as all necessary bits for the "EFI image loader" interfaces.
>>
>> Signed-off-by: Alexander Graf <agraf@suse.de>
>> ---
>>  include/efi_loader.h              |  37 +++++
>>  include/pe.h                      | 277 ++++++++++++++++++++++++++++++++++++++
>>  lib/efi_loader/efi_image_loader.c | 203 ++++++++++++++++++++++++++++
>>  3 files changed, 517 insertions(+)
>>  create mode 100644 include/efi_loader.h
>>  create mode 100644 include/pe.h
>>  create mode 100644 lib/efi_loader/efi_image_loader.c
>>
>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>> new file mode 100644
>> index 0000000..da82354
>> --- /dev/null
>> +++ b/include/efi_loader.h
>> @@ -0,0 +1,37 @@
>> +/*
>> + *  EFI application loader
>> + *
>> + *  Copyright (c) 2015 Alexander Graf
>> + *
>> + *  This library is free software; you can redistribute it and/or
>> + *  modify it under the terms of the GNU Lesser General Public
>> + *  License as published by the Free Software Foundation; either
>> + *  version 2.1 of the License, or (at your option) any later version.
>> + *
>> + *  This library is distributed in the hope that it will be useful,
>> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + *  Lesser General Public License for more details.
>> + *
>> + *  You should have received a copy of the GNU Lesser General Public
>> + *  License along with this library; if not, write to the Free Software
>> + *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
>> + *
>> + *  SPDX-License-Identifier:     LGPL-2.1+
>> + */
>> +
>> +#include <part_efi.h>
>> +#include <efi_api.h>
>> +#include <linux/list.h>
>> +
>> +extern const efi_guid_t efi_guid_device_path;
>> +extern const efi_guid_t efi_guid_loaded_image;
>> +
>> +efi_status_t efi_return_handle(void *handle,
>> +		efi_guid_t *protocol, void **protocol_interface,
>> +		void *agent_handle, void *controller_handle,
>> +		uint32_t attributes);
>> +void *efi_load_pe(void *efi, struct efi_loaded_image *loaded_image_info);
>> +
>> +#define EFI_LOADER_POOL_SIZE (128 * 1024 * 1024)
>> +void *efi_loader_alloc(uint64_t len);
>> diff --git a/include/pe.h b/include/pe.h
>> new file mode 100644
>> index 0000000..009b0c5
>> --- /dev/null
>> +++ b/include/pe.h
>> @@ -0,0 +1,277 @@
>> +/*
>> + *  Portable Executable binary format structures
>> + *
>> + *  Copyright (c) 2015 Alexander Graf
>> + *
>> + *  Based on wine code
>> + *
>> + *  This library is free software; you can redistribute it and/or
>> + *  modify it under the terms of the GNU Lesser General Public
>> + *  License as published by the Free Software Foundation; either
>> + *  version 2.1 of the License, or (at your option) any later version.
>> + *
>> + *  This library is distributed in the hope that it will be useful,
>> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + *  Lesser General Public License for more details.
>> + *
>> + *  You should have received a copy of the GNU Lesser General Public
>> + *  License along with this library; if not, write to the Free Software
>> + *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
>> + *
>> + *  SPDX-License-Identifier:     LGPL-2.1+
>> + */
>> +
>> +#ifndef _PE_H
>> +#define _PE_H
>> +
>> +typedef struct _IMAGE_DOS_HEADER {
>> +	uint16_t e_magic;      /* 00: MZ Header signature */
>> +	uint16_t e_cblp;       /* 02: Bytes on last page of file */
>> +	uint16_t e_cp;         /* 04: Pages in file */
>> +	uint16_t e_crlc;       /* 06: Relocations */
>> +	uint16_t e_cparhdr;    /* 08: Size of header in paragraphs */
>> +	uint16_t e_minalloc;   /* 0a: Minimum extra paragraphs needed */
>> +	uint16_t e_maxalloc;   /* 0c: Maximum extra paragraphs needed */
>> +	uint16_t e_ss;         /* 0e: Initial (relative) SS value */
>> +	uint16_t e_sp;         /* 10: Initial SP value */
>> +	uint16_t e_csum;       /* 12: Checksum */
>> +	uint16_t e_ip;         /* 14: Initial IP value */
>> +	uint16_t e_cs;         /* 16: Initial (relative) CS value */
>> +	uint16_t e_lfarlc;     /* 18: File address of relocation table */
>> +	uint16_t e_ovno;       /* 1a: Overlay number */
>> +	uint16_t e_res[4];     /* 1c: Reserved words */
>> +	uint16_t e_oemid;      /* 24: OEM identifier (for e_oeminfo) */
>> +	uint16_t e_oeminfo;    /* 26: OEM information; e_oemid specific */
>> +	uint16_t e_res2[10];   /* 28: Reserved words */
>> +	uint32_t e_lfanew;     /* 3c: Offset to extended header */
>> +} IMAGE_DOS_HEADER, *PIMAGE_DOS_HEADER;
>> +
>> +#define IMAGE_DOS_SIGNATURE		0x5A4D     /* MZ   */
>> +#define IMAGE_NT_SIGNATURE		0x00004550 /* PE00 */
>> +
>> +#define IMAGE_FILE_MACHINE_ARM		0x01c0
>> +#define IMAGE_FILE_MACHINE_THUMB	0x01c2
>> +#define IMAGE_FILE_MACHINE_ARMNT	0x01c4
>> +#define IMAGE_FILE_MACHINE_AMD64	0x8664
>> +#define IMAGE_FILE_MACHINE_ARM64	0xaa64
>> +#define IMAGE_NT_OPTIONAL_HDR32_MAGIC	0x10b
>> +#define IMAGE_NT_OPTIONAL_HDR64_MAGIC	0x20b
>> +#define IMAGE_SUBSYSTEM_EFI_APPLICATION	10
>> +
>> +typedef struct _IMAGE_FILE_HEADER {
>> +	uint16_t  Machine;
>> +	uint16_t  NumberOfSections;
>> +	uint32_t TimeDateStamp;
>> +	uint32_t PointerToSymbolTable;
>> +	uint32_t NumberOfSymbols;
>> +	uint16_t  SizeOfOptionalHeader;
>> +	uint16_t  Characteristics;
>> +} IMAGE_FILE_HEADER, *PIMAGE_FILE_HEADER;
>> +
>> +typedef struct _IMAGE_DATA_DIRECTORY {
>> +	uint32_t VirtualAddress;
>> +	uint32_t Size;
>> +} IMAGE_DATA_DIRECTORY, *PIMAGE_DATA_DIRECTORY;
>> +
>> +#define IMAGE_NUMBEROF_DIRECTORY_ENTRIES 16
>> +
>> +typedef struct _IMAGE_OPTIONAL_HEADER64 {
>> +	uint16_t  Magic; /* 0x20b */
>> +	uint8_t MajorLinkerVersion;
>> +	uint8_t MinorLinkerVersion;
>> +	uint32_t SizeOfCode;
>> +	uint32_t SizeOfInitializedData;
>> +	uint32_t SizeOfUninitializedData;
>> +	uint32_t AddressOfEntryPoint;
>> +	uint32_t BaseOfCode;
>> +	uint64_t ImageBase;
>> +	uint32_t SectionAlignment;
>> +	uint32_t FileAlignment;
>> +	uint16_t MajorOperatingSystemVersion;
>> +	uint16_t MinorOperatingSystemVersion;
>> +	uint16_t MajorImageVersion;
>> +	uint16_t MinorImageVersion;
>> +	uint16_t MajorSubsystemVersion;
>> +	uint16_t MinorSubsystemVersion;
>> +	uint32_t Win32VersionValue;
>> +	uint32_t SizeOfImage;
>> +	uint32_t SizeOfHeaders;
>> +	uint32_t CheckSum;
>> +	uint16_t Subsystem;
>> +	uint16_t DllCharacteristics;
>> +	uint64_t SizeOfStackReserve;
>> +	uint64_t SizeOfStackCommit;
>> +	uint64_t SizeOfHeapReserve;
>> +	uint64_t SizeOfHeapCommit;
>> +	uint32_t LoaderFlags;
>> +	uint32_t NumberOfRvaAndSizes;
>> +	IMAGE_DATA_DIRECTORY DataDirectory[IMAGE_NUMBEROF_DIRECTORY_ENTRIES];
>> +} IMAGE_OPTIONAL_HEADER64, *PIMAGE_OPTIONAL_HEADER64;
>> +
>> +typedef struct _IMAGE_NT_HEADERS64 {
>> +	uint32_t Signature;
>> +	IMAGE_FILE_HEADER FileHeader;
>> +	IMAGE_OPTIONAL_HEADER64 OptionalHeader;
>> +} IMAGE_NT_HEADERS64, *PIMAGE_NT_HEADERS64;
>> +
>> +typedef struct _IMAGE_OPTIONAL_HEADER {
>> +
>> +	/* Standard fields */
>> +
>> +	uint16_t  Magic; /* 0x10b or 0x107 */     /* 0x00 */
>> +	uint8_t  MajorLinkerVersion;
>> +	uint8_t  MinorLinkerVersion;
>> +	uint32_t SizeOfCode;
>> +	uint32_t SizeOfInitializedData;
>> +	uint32_t SizeOfUninitializedData;
>> +	uint32_t AddressOfEntryPoint;            /* 0x10 */
>> +	uint32_t BaseOfCode;
>> +	uint32_t BaseOfData;
>> +
>> +	/* NT additional fields */
>> +
>> +	uint32_t ImageBase;
>> +	uint32_t SectionAlignment;               /* 0x20 */
>> +	uint32_t FileAlignment;
>> +	uint16_t  MajorOperatingSystemVersion;
>> +	uint16_t  MinorOperatingSystemVersion;
>> +	uint16_t  MajorImageVersion;
>> +	uint16_t  MinorImageVersion;
>> +	uint16_t  MajorSubsystemVersion;          /* 0x30 */
>> +	uint16_t  MinorSubsystemVersion;
>> +	uint32_t Win32VersionValue;
>> +	uint32_t SizeOfImage;
>> +	uint32_t SizeOfHeaders;
>> +	uint32_t CheckSum;                       /* 0x40 */
>> +	uint16_t  Subsystem;
>> +	uint16_t  DllCharacteristics;
>> +	uint32_t SizeOfStackReserve;
>> +	uint32_t SizeOfStackCommit;
>> +	uint32_t SizeOfHeapReserve;              /* 0x50 */
>> +	uint32_t SizeOfHeapCommit;
>> +	uint32_t LoaderFlags;
>> +	uint32_t NumberOfRvaAndSizes;
>> +	IMAGE_DATA_DIRECTORY DataDirectory[IMAGE_NUMBEROF_DIRECTORY_ENTRIES]; /* 0x60 */
>> +	/* 0xE0 */
>> +} IMAGE_OPTIONAL_HEADER32, *PIMAGE_OPTIONAL_HEADER32;
>> +
>> +typedef struct _IMAGE_NT_HEADERS {
>> +	uint32_t Signature; /* "PE"\0\0 */       /* 0x00 */
>> +	IMAGE_FILE_HEADER FileHeader;         /* 0x04 */
>> +	IMAGE_OPTIONAL_HEADER32 OptionalHeader;       /* 0x18 */
>> +} IMAGE_NT_HEADERS32, *PIMAGE_NT_HEADERS32;
>> +
>> +#define IMAGE_SIZEOF_SHORT_NAME 8
>> +
>> +typedef struct _IMAGE_SECTION_HEADER {
>> +	uint8_t	Name[IMAGE_SIZEOF_SHORT_NAME];
>> +	union {
>> +		uint32_t PhysicalAddress;
>> +		uint32_t VirtualSize;
>> +	} Misc;
>> +	uint32_t VirtualAddress;
>> +	uint32_t SizeOfRawData;
>> +	uint32_t PointerToRawData;
>> +	uint32_t PointerToRelocations;
>> +	uint32_t PointerToLinenumbers;
>> +	uint16_t	NumberOfRelocations;
>> +	uint16_t	NumberOfLinenumbers;
>> +	uint32_t Characteristics;
>> +} IMAGE_SECTION_HEADER, *PIMAGE_SECTION_HEADER;
>> +
>> +#define IMAGE_DIRECTORY_ENTRY_BASERELOC         5
>> +
>> +typedef struct _IMAGE_BASE_RELOCATION
>> +{
>> +        uint32_t VirtualAddress;
>> +        uint32_t SizeOfBlock;
>> +        /* WORD TypeOffset[1]; */
>> +} IMAGE_BASE_RELOCATION,*PIMAGE_BASE_RELOCATION;
>> +
>> +typedef struct _IMAGE_RELOCATION
>> +{
>> +	union {
>> +		uint32_t   VirtualAddress;
>> +		uint32_t   RelocCount;
>> +	} DUMMYUNIONNAME;
>> +	uint32_t   SymbolTableIndex;
>> +	uint16_t	Type;
>> +} IMAGE_RELOCATION, *PIMAGE_RELOCATION;
>> +
>> +#define IMAGE_SIZEOF_RELOCATION 10
>> +
>> +/* generic relocation types */
>> +#define IMAGE_REL_BASED_ABSOLUTE                0
>> +#define IMAGE_REL_BASED_HIGH                    1
>> +#define IMAGE_REL_BASED_LOW                     2
>> +#define IMAGE_REL_BASED_HIGHLOW                 3
>> +#define IMAGE_REL_BASED_HIGHADJ                 4
>> +#define IMAGE_REL_BASED_MIPS_JMPADDR            5
>> +#define IMAGE_REL_BASED_ARM_MOV32A              5 /* yes, 5 too */
>> +#define IMAGE_REL_BASED_ARM_MOV32               5 /* yes, 5 too */
>> +#define IMAGE_REL_BASED_SECTION                 6
>> +#define IMAGE_REL_BASED_REL                     7
>> +#define IMAGE_REL_BASED_ARM_MOV32T              7 /* yes, 7 too */
>> +#define IMAGE_REL_BASED_THUMB_MOV32             7 /* yes, 7 too */
>> +#define IMAGE_REL_BASED_MIPS_JMPADDR16          9
>> +#define IMAGE_REL_BASED_IA64_IMM64              9 /* yes, 9 too */
>> +#define IMAGE_REL_BASED_DIR64                   10
>> +#define IMAGE_REL_BASED_HIGH3ADJ                11
>> +
>> +/* ARM relocation types */
>> +#define IMAGE_REL_ARM_ABSOLUTE          0x0000
>> +#define IMAGE_REL_ARM_ADDR              0x0001
>> +#define IMAGE_REL_ARM_ADDR32NB          0x0002
>> +#define IMAGE_REL_ARM_BRANCH24          0x0003
>> +#define IMAGE_REL_ARM_BRANCH11          0x0004
>> +#define IMAGE_REL_ARM_TOKEN             0x0005
>> +#define IMAGE_REL_ARM_GPREL12           0x0006
>> +#define IMAGE_REL_ARM_GPREL7            0x0007
>> +#define IMAGE_REL_ARM_BLX24             0x0008
>> +#define IMAGE_REL_ARM_BLX11             0x0009
>> +#define IMAGE_REL_ARM_SECTION           0x000E
>> +#define IMAGE_REL_ARM_SECREL            0x000F
>> +#define IMAGE_REL_ARM_MOV32A            0x0010
>> +#define IMAGE_REL_ARM_MOV32T            0x0011
>> +#define IMAGE_REL_ARM_BRANCH20T 0x0012
>> +#define IMAGE_REL_ARM_BRANCH24T 0x0014
>> +#define IMAGE_REL_ARM_BLX23T            0x0015
>> +
>> +/* ARM64 relocation types */
>> +#define IMAGE_REL_ARM64_ABSOLUTE        0x0000
>> +#define IMAGE_REL_ARM64_ADDR32          0x0001
>> +#define IMAGE_REL_ARM64_ADDR32NB        0x0002
>> +#define IMAGE_REL_ARM64_BRANCH26        0x0003
>> +#define IMAGE_REL_ARM64_PAGEBASE_REL21  0x0004
>> +#define IMAGE_REL_ARM64_REL21           0x0005
>> +#define IMAGE_REL_ARM64_PAGEOFFSET_12A  0x0006
>> +#define IMAGE_REL_ARM64_PAGEOFFSET_12L  0x0007
>> +#define IMAGE_REL_ARM64_SECREL          0x0008
>> +#define IMAGE_REL_ARM64_SECREL_LOW12A   0x0009
>> +#define IMAGE_REL_ARM64_SECREL_HIGH12A  0x000A
>> +#define IMAGE_REL_ARM64_SECREL_LOW12L   0x000B
>> +#define IMAGE_REL_ARM64_TOKEN           0x000C
>> +#define IMAGE_REL_ARM64_SECTION         0x000D
>> +#define IMAGE_REL_ARM64_ADDR64          0x000E
>> +
>> +/* AMD64 relocation types */
>> +#define IMAGE_REL_AMD64_ABSOLUTE        0x0000
>> +#define IMAGE_REL_AMD64_ADDR64          0x0001
>> +#define IMAGE_REL_AMD64_ADDR32          0x0002
>> +#define IMAGE_REL_AMD64_ADDR32NB        0x0003
>> +#define IMAGE_REL_AMD64_REL32           0x0004
>> +#define IMAGE_REL_AMD64_REL32_1         0x0005
>> +#define IMAGE_REL_AMD64_REL32_2         0x0006
>> +#define IMAGE_REL_AMD64_REL32_3         0x0007
>> +#define IMAGE_REL_AMD64_REL32_4         0x0008
>> +#define IMAGE_REL_AMD64_REL32_5         0x0009
>> +#define IMAGE_REL_AMD64_SECTION         0x000A
>> +#define IMAGE_REL_AMD64_SECREL          0x000B
>> +#define IMAGE_REL_AMD64_SECREL7         0x000C
>> +#define IMAGE_REL_AMD64_TOKEN           0x000D
>> +#define IMAGE_REL_AMD64_SREL32          0x000E
>> +#define IMAGE_REL_AMD64_PAIR            0x000F
>> +#define IMAGE_REL_AMD64_SSPAN32         0x0010
>> +
>> +#endif /* _PE_H */
>> diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
>> new file mode 100644
>> index 0000000..688e177
>> --- /dev/null
>> +++ b/lib/efi_loader/efi_image_loader.c
>> @@ -0,0 +1,203 @@
>> +/*
>> + *  EFI image loader
>> + *
>> + *  based partly on wine code
>> + *
>> + *  Copyright (c) 2015 Alexander Graf
>> + *
>> + *  This library is free software; you can redistribute it and/or
>> + *  modify it under the terms of the GNU Lesser General Public
>> + *  License as published by the Free Software Foundation; either
>> + *  version 2.1 of the License, or (at your option) any later version.
>> + *
>> + *  This library is distributed in the hope that it will be useful,
>> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> + *  Lesser General Public License for more details.
>> + *
>> + *  You should have received a copy of the GNU Lesser General Public
>> + *  License along with this library; if not, write to the Free Software
>> + *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
>> + *
>> + *  SPDX-License-Identifier:     LGPL-2.1+
>> + */
>> +
>> +#include <common.h>
>> +#include <pe.h>
>> +#include <efi_loader.h>
>> +#include <asm/global_data.h>
>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +#define ROUND_UP(val, round) ((val + (round - 1)) & ~(round - 1))
>> +#define MB (1024 * 1024)
>> +
>> +const efi_guid_t efi_guid_device_path = DEVICE_PATH_GUID;
>> +const efi_guid_t efi_guid_loaded_image = LOADED_IMAGE_GUID;
>> +
>> +efi_status_t efi_return_handle(void *handle, efi_guid_t *protocol,
>> +			void **protocol_interface, void *agent_handle,
>> +			void *controller_handle, uint32_t attributes)
>> +{
>> +	*protocol_interface = handle;
>> +	return EFI_SUCCESS;
>> +}
>> +
>> +/*
>> + * EFI payloads potentially want to load pretty big images into memory,
>> + * so our small malloc region isn't enough for them. However, they usually
>> + * don't need a smart allocator either.
>> + *
>> + * So instead give them a really dumb one. We just reserve EFI_LOADER_POOL_SIZE
>> + * bytes from 16MB below the malloc region start to give the stack some space.
> 
> Is there any chance you could break out the memory allocation and
> memory map management as a separate patch, rather than spread across
> 3,4 and 6?

Uh, sure, I can try. I'm not sure it'll end up more readable than now
though :).

> 
> Assigning a specific 128MB pool for LOADER_DATA memory can have
> unexpected side effects.

Like for example?

> 
>> + * Then every allocation gets a 4k aligned chunk from it. We never free.
> 
> Never freeing LOADER_DATA should not be an issue in and of itself. It
> all gets zapped by the OS anyway.

That's the idea, yes :).

> 
>> + */
>> +void *efi_loader_alloc(uint64_t len)
>> +{
>> +	static unsigned long loader_pool;
>> +	void *r;
>> +
>> +	if (!loader_pool) {
>> +		loader_pool = gd->relocaddr - TOTAL_MALLOC_LEN -
>> +			      EFI_LOADER_POOL_SIZE - (16 * MB);
>> +	}
>> +
>> +	len = ROUND_UP(len, 4096);
>> +	/* Out of memory */
>> +	if ((loader_pool + len) >= (gd->relocaddr - TOTAL_MALLOC_LEN))
>> +		return NULL;
>> +
>> +	r = (void *)loader_pool;
>> +	loader_pool += len;
>> +
>> +	return r;
>> +}
>> +
>> +/*
>> + * This function loads all sections from a PE binary into a newly reserved
>> + * piece of memory. On successful load it then returns the entry point for
>> + * the binary. Otherwise NULL.
>> + */
>> +void *efi_load_pe(void *efi, struct efi_loaded_image *loaded_image_info)
>> +{
>> +	IMAGE_NT_HEADERS32 *nt;
>> +	IMAGE_DOS_HEADER *dos;
>> +	IMAGE_SECTION_HEADER *sections;
>> +	int num_sections;
>> +	void *efi_reloc;
>> +	int i;
>> +	const uint16_t *relocs;
>> +	const IMAGE_BASE_RELOCATION *rel;
>> +	const IMAGE_BASE_RELOCATION *end;
>> +	unsigned long rel_size;
>> +	int rel_idx = IMAGE_DIRECTORY_ENTRY_BASERELOC;
>> +	void *entry;
>> +	uint64_t image_size;
>> +	unsigned long virt_size = 0;
>> +
>> +	dos = efi;
>> +	if (dos->e_magic != IMAGE_DOS_SIGNATURE) {
>> +		printf("%s: Invalid DOS Signature\n", __func__);
>> +		return NULL;
>> +	}
>> +
>> +	nt = (void *) ((char *)efi + dos->e_lfanew);
>> +	if (nt->Signature != IMAGE_NT_SIGNATURE) {
>> +		printf("%s: Invalid NT Signature\n", __func__);
>> +		return NULL;
>> +	}
>> +
>> +	/* Calculate upper virtual address boundary */
>> +	num_sections = nt->FileHeader.NumberOfSections;
>> +	sections = (void *)&nt->OptionalHeader +
>> +			    nt->FileHeader.SizeOfOptionalHeader;
>> +
>> +	for (i = num_sections - 1; i >= 0; i--) {
>> +		IMAGE_SECTION_HEADER *sec = &sections[i];
>> +		virt_size = max_t(unsigned long, virt_size,
>> +				  sec->VirtualAddress + sec->Misc.VirtualSize);
>> +	}
>> +
>> +	/* Read 32/64bit specific header bits */
> 
> I guess x86 may support 32-on-64 or 64-on-32, but ARM won't - so could
> probably be compile-time conditionalised somehow.
> (CONFIG_EFI_SUPPORTS_PE32/CONFIG_EFI_SUPPORTS_PE64)

I think I have a reasonably elegant solution now. I hope.

> 
>> +	if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
>> +		IMAGE_NT_HEADERS64 *nt64 = (void *)nt;
>> +		IMAGE_OPTIONAL_HEADER64 *opt = &nt64->OptionalHeader;
>> +		image_size = opt->SizeOfImage;
>> +		efi_reloc = efi_loader_alloc(virt_size);
>> +		if (!efi_reloc) {
>> +			printf("%s: Could not allocate %ld bytes\n",
>> +				__func__, virt_size);
>> +			return NULL;
>> +		}
>> +		entry = efi_reloc + opt->AddressOfEntryPoint;
>> +		rel_size = opt->DataDirectory[rel_idx].Size;
>> +		rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
>> +	} else {
> 
> ...and should still check the magic value for 32-bit?

True.


Alex