linux-stable/arch/arm64/kernel/efi-header.S
Ard Biesheuvel 7919385b9f arm64: head: tidy up the Image header definition
Even though support for EFI boot remains entirely optional for arm64,
it is unlikely that we will ever be able to repurpose the image header
fields that the EFI loader relies on, i.e., the magic NOP at offset
0x0 and the PE header address at offset 0x3c.

So let's factor out the differences into a 'efi_signature_nop' macro and
a local symbol representing the PE header address, and move the
conditional definitions into efi-header.S, taking into account whether
CONFIG_EFI is enabled or not. While at it, switch to a signature NOP
that behaves more like a NOP, i.e., one that only clobbers the
flags.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201117124729.12642-4-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-11-17 16:14:20 +00:00

166 lines
5 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2013 - 2017 Linaro, Ltd.
* Copyright (C) 2013, 2014 Red Hat, Inc.
*/
#include <linux/pe.h>
#include <linux/sizes.h>
.macro efi_signature_nop
#ifdef CONFIG_EFI
.L_head:
/*
* This ccmp instruction has no meaningful effect except that
* its opcode forms the magic "MZ" signature required by UEFI.
*/
ccmp x18, #0, #0xd, pl
#else
/*
* Bootloaders may inspect the opcode at the start of the kernel
* image to decide if the kernel is capable of booting via UEFI.
* So put an ordinary NOP here, not the "MZ.." pseudo-nop above.
*/
nop
#endif
.endm
.macro __EFI_PE_HEADER
#ifdef CONFIG_EFI
.set .Lpe_header_offset, . - .L_head
.long PE_MAGIC
.short IMAGE_FILE_MACHINE_ARM64 // Machine
.short .Lsection_count // NumberOfSections
.long 0 // TimeDateStamp
.long 0 // PointerToSymbolTable
.long 0 // NumberOfSymbols
.short .Lsection_table - .Loptional_header // SizeOfOptionalHeader
.short IMAGE_FILE_DEBUG_STRIPPED | \
IMAGE_FILE_EXECUTABLE_IMAGE | \
IMAGE_FILE_LINE_NUMS_STRIPPED // Characteristics
.Loptional_header:
.short PE_OPT_MAGIC_PE32PLUS // PE32+ format
.byte 0x02 // MajorLinkerVersion
.byte 0x14 // MinorLinkerVersion
.long __initdata_begin - .Lefi_header_end // SizeOfCode
.long __pecoff_data_size // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
.long __efistub_efi_pe_entry - .L_head // AddressOfEntryPoint
.long .Lefi_header_end - .L_head // BaseOfCode
.quad 0 // ImageBase
.long SEGMENT_ALIGN // SectionAlignment
.long PECOFF_FILE_ALIGNMENT // FileAlignment
.short 0 // MajorOperatingSystemVersion
.short 0 // MinorOperatingSystemVersion
.short LINUX_EFISTUB_MAJOR_VERSION // MajorImageVersion
.short LINUX_EFISTUB_MINOR_VERSION // MinorImageVersion
.short 0 // MajorSubsystemVersion
.short 0 // MinorSubsystemVersion
.long 0 // Win32VersionValue
.long _end - .L_head // SizeOfImage
// Everything before the kernel image is considered part of the header
.long .Lefi_header_end - .L_head // SizeOfHeaders
.long 0 // CheckSum
.short IMAGE_SUBSYSTEM_EFI_APPLICATION // Subsystem
.short 0 // DllCharacteristics
.quad 0 // SizeOfStackReserve
.quad 0 // SizeOfStackCommit
.quad 0 // SizeOfHeapReserve
.quad 0 // SizeOfHeapCommit
.long 0 // LoaderFlags
.long (.Lsection_table - .) / 8 // NumberOfRvaAndSizes
.quad 0 // ExportTable
.quad 0 // ImportTable
.quad 0 // ResourceTable
.quad 0 // ExceptionTable
.quad 0 // CertificationTable
.quad 0 // BaseRelocationTable
#ifdef CONFIG_DEBUG_EFI
.long .Lefi_debug_table - .L_head // DebugTable
.long .Lefi_debug_table_size
#endif
// Section table
.Lsection_table:
.ascii ".text\0\0\0"
.long __initdata_begin - .Lefi_header_end // VirtualSize
.long .Lefi_header_end - .L_head // VirtualAddress
.long __initdata_begin - .Lefi_header_end // SizeOfRawData
.long .Lefi_header_end - .L_head // PointerToRawData
.long 0 // PointerToRelocations
.long 0 // PointerToLineNumbers
.short 0 // NumberOfRelocations
.short 0 // NumberOfLineNumbers
.long IMAGE_SCN_CNT_CODE | \
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_EXECUTE // Characteristics
.ascii ".data\0\0\0"
.long __pecoff_data_size // VirtualSize
.long __initdata_begin - .L_head // VirtualAddress
.long __pecoff_data_rawsize // SizeOfRawData
.long __initdata_begin - .L_head // PointerToRawData
.long 0 // PointerToRelocations
.long 0 // PointerToLineNumbers
.short 0 // NumberOfRelocations
.short 0 // NumberOfLineNumbers
.long IMAGE_SCN_CNT_INITIALIZED_DATA | \
IMAGE_SCN_MEM_READ | \
IMAGE_SCN_MEM_WRITE // Characteristics
.set .Lsection_count, (. - .Lsection_table) / 40
#ifdef CONFIG_DEBUG_EFI
/*
* The debug table is referenced via its Relative Virtual Address (RVA),
* which is only defined for those parts of the image that are covered
* by a section declaration. Since this header is not covered by any
* section, the debug table must be emitted elsewhere. So stick it in
* the .init.rodata section instead.
*
* Note that the EFI debug entry itself may legally have a zero RVA,
* which means we can simply put it right after the section headers.
*/
__INITRODATA
.align 2
.Lefi_debug_table:
// EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
.long 0 // Characteristics
.long 0 // TimeDateStamp
.short 0 // MajorVersion
.short 0 // MinorVersion
.long IMAGE_DEBUG_TYPE_CODEVIEW // Type
.long .Lefi_debug_entry_size // SizeOfData
.long 0 // RVA
.long .Lefi_debug_entry - .L_head // FileOffset
.set .Lefi_debug_table_size, . - .Lefi_debug_table
.previous
.Lefi_debug_entry:
// EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
.ascii "NB10" // Signature
.long 0 // Unknown
.long 0 // Unknown2
.long 0 // Unknown3
.asciz VMLINUX_PATH
.set .Lefi_debug_entry_size, . - .Lefi_debug_entry
#endif
.balign SEGMENT_ALIGN
.Lefi_header_end:
#else
.set .Lpe_header_offset, 0x0
#endif
.endm