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https://github.com/edk2-porting/linux-next.git
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546c8c44f0
Apart from the arm64/linux and EFI header data structures, there is nothing in the .head.text section that must reside at the beginning of the Image. So let's move it to the .init section where it belongs. Note that this involves some minor tweaking of the EFI header, primarily because the address of 'stext' no longer coincides with the start of the .text section. It also requires a couple of relocated symbol references to be slightly rewritten or their definition moved to the linker script. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
809 lines
22 KiB
ArmAsm
809 lines
22 KiB
ArmAsm
/*
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* Low-level CPU initialisation
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* Based on arch/arm/kernel/head.S
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*
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* Copyright (C) 1994-2002 Russell King
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* Copyright (C) 2003-2012 ARM Ltd.
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* Authors: Catalin Marinas <catalin.marinas@arm.com>
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* Will Deacon <will.deacon@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <linux/irqchip/arm-gic-v3.h>
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#include <asm/assembler.h>
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#include <asm/ptrace.h>
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#include <asm/asm-offsets.h>
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#include <asm/cache.h>
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#include <asm/cputype.h>
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#include <asm/elf.h>
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#include <asm/kernel-pgtable.h>
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#include <asm/kvm_arm.h>
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#include <asm/memory.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/pgtable.h>
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#include <asm/page.h>
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#include <asm/smp.h>
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#include <asm/sysreg.h>
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#include <asm/thread_info.h>
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#include <asm/virt.h>
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#define __PHYS_OFFSET (KERNEL_START - TEXT_OFFSET)
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#if (TEXT_OFFSET & 0xfff) != 0
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#error TEXT_OFFSET must be at least 4KB aligned
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#elif (PAGE_OFFSET & 0x1fffff) != 0
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#error PAGE_OFFSET must be at least 2MB aligned
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#elif TEXT_OFFSET > 0x1fffff
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#error TEXT_OFFSET must be less than 2MB
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#endif
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#define KERNEL_START _text
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#define KERNEL_END _end
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/*
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* Kernel startup entry point.
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* ---------------------------
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*
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* The requirements are:
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* MMU = off, D-cache = off, I-cache = on or off,
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* x0 = physical address to the FDT blob.
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*
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* This code is mostly position independent so you call this at
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* __pa(PAGE_OFFSET + TEXT_OFFSET).
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*
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* Note that the callee-saved registers are used for storing variables
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* that are useful before the MMU is enabled. The allocations are described
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* in the entry routines.
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*/
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__HEAD
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_head:
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/*
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* DO NOT MODIFY. Image header expected by Linux boot-loaders.
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*/
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#ifdef CONFIG_EFI
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/*
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* This add instruction has no meaningful effect except that
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* its opcode forms the magic "MZ" signature required by UEFI.
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*/
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add x13, x18, #0x16
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b stext
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#else
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b stext // branch to kernel start, magic
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.long 0 // reserved
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#endif
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le64sym _kernel_offset_le // Image load offset from start of RAM, little-endian
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le64sym _kernel_size_le // Effective size of kernel image, little-endian
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le64sym _kernel_flags_le // Informative flags, little-endian
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.quad 0 // reserved
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.quad 0 // reserved
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.quad 0 // reserved
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.byte 0x41 // Magic number, "ARM\x64"
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.byte 0x52
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.byte 0x4d
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.byte 0x64
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#ifdef CONFIG_EFI
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.long pe_header - _head // Offset to the PE header.
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#else
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.word 0 // reserved
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#endif
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#ifdef CONFIG_EFI
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.align 3
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pe_header:
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.ascii "PE"
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.short 0
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coff_header:
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.short 0xaa64 // AArch64
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.short 2 // nr_sections
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.long 0 // TimeDateStamp
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.long 0 // PointerToSymbolTable
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.long 1 // NumberOfSymbols
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.short section_table - optional_header // SizeOfOptionalHeader
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.short 0x206 // Characteristics.
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// IMAGE_FILE_DEBUG_STRIPPED |
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// IMAGE_FILE_EXECUTABLE_IMAGE |
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// IMAGE_FILE_LINE_NUMS_STRIPPED
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optional_header:
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.short 0x20b // PE32+ format
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.byte 0x02 // MajorLinkerVersion
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.byte 0x14 // MinorLinkerVersion
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.long _end - efi_header_end // SizeOfCode
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.long 0 // SizeOfInitializedData
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.long 0 // SizeOfUninitializedData
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.long __efistub_entry - _head // AddressOfEntryPoint
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.long efi_header_end - _head // BaseOfCode
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extra_header_fields:
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.quad 0 // ImageBase
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.long 0x1000 // SectionAlignment
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.long PECOFF_FILE_ALIGNMENT // FileAlignment
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.short 0 // MajorOperatingSystemVersion
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.short 0 // MinorOperatingSystemVersion
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.short 0 // MajorImageVersion
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.short 0 // MinorImageVersion
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.short 0 // MajorSubsystemVersion
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.short 0 // MinorSubsystemVersion
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.long 0 // Win32VersionValue
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.long _end - _head // SizeOfImage
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// Everything before the kernel image is considered part of the header
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.long efi_header_end - _head // SizeOfHeaders
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.long 0 // CheckSum
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.short 0xa // Subsystem (EFI application)
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.short 0 // DllCharacteristics
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.quad 0 // SizeOfStackReserve
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.quad 0 // SizeOfStackCommit
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.quad 0 // SizeOfHeapReserve
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.quad 0 // SizeOfHeapCommit
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.long 0 // LoaderFlags
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.long 0x6 // NumberOfRvaAndSizes
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.quad 0 // ExportTable
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.quad 0 // ImportTable
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.quad 0 // ResourceTable
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.quad 0 // ExceptionTable
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.quad 0 // CertificationTable
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.quad 0 // BaseRelocationTable
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// Section table
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section_table:
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/*
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* The EFI application loader requires a relocation section
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* because EFI applications must be relocatable. This is a
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* dummy section as far as we are concerned.
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*/
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.ascii ".reloc"
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.byte 0
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.byte 0 // end of 0 padding of section name
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.long 0
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.long 0
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.long 0 // SizeOfRawData
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.long 0 // PointerToRawData
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.long 0 // PointerToRelocations
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.long 0 // PointerToLineNumbers
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.short 0 // NumberOfRelocations
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.short 0 // NumberOfLineNumbers
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.long 0x42100040 // Characteristics (section flags)
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.ascii ".text"
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.byte 0
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.byte 0
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.byte 0 // end of 0 padding of section name
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.long _end - efi_header_end // VirtualSize
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.long efi_header_end - _head // VirtualAddress
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.long _edata - efi_header_end // SizeOfRawData
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.long efi_header_end - _head // PointerToRawData
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.long 0 // PointerToRelocations (0 for executables)
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.long 0 // PointerToLineNumbers (0 for executables)
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.short 0 // NumberOfRelocations (0 for executables)
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.short 0 // NumberOfLineNumbers (0 for executables)
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.long 0xe0500020 // Characteristics (section flags)
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/*
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* EFI will load .text onwards at the 4k section alignment
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* described in the PE/COFF header. To ensure that instruction
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* sequences using an adrp and a :lo12: immediate will function
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* correctly at this alignment, we must ensure that .text is
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* placed at a 4k boundary in the Image to begin with.
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*/
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.align 12
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efi_header_end:
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#endif
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__INIT
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ENTRY(stext)
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bl preserve_boot_args
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bl el2_setup // Drop to EL1, w20=cpu_boot_mode
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mov x23, xzr // KASLR offset, defaults to 0
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adrp x24, __PHYS_OFFSET
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bl set_cpu_boot_mode_flag
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bl __create_page_tables // x25=TTBR0, x26=TTBR1
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/*
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* The following calls CPU setup code, see arch/arm64/mm/proc.S for
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* details.
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* On return, the CPU will be ready for the MMU to be turned on and
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* the TCR will have been set.
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*/
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ldr x27, 0f // address to jump to after
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neg x27, x27 // MMU has been enabled
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adr_l lr, __enable_mmu // return (PIC) address
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b __cpu_setup // initialise processor
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ENDPROC(stext)
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.align 3
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0: .quad (_text - TEXT_OFFSET) - __mmap_switched - KIMAGE_VADDR
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/*
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* Preserve the arguments passed by the bootloader in x0 .. x3
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*/
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preserve_boot_args:
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mov x21, x0 // x21=FDT
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adr_l x0, boot_args // record the contents of
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stp x21, x1, [x0] // x0 .. x3 at kernel entry
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stp x2, x3, [x0, #16]
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dmb sy // needed before dc ivac with
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// MMU off
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add x1, x0, #0x20 // 4 x 8 bytes
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b __inval_cache_range // tail call
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ENDPROC(preserve_boot_args)
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/*
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* Macro to create a table entry to the next page.
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*
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* tbl: page table address
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* virt: virtual address
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* shift: #imm page table shift
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* ptrs: #imm pointers per table page
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*
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* Preserves: virt
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* Corrupts: tmp1, tmp2
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* Returns: tbl -> next level table page address
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*/
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.macro create_table_entry, tbl, virt, shift, ptrs, tmp1, tmp2
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lsr \tmp1, \virt, #\shift
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and \tmp1, \tmp1, #\ptrs - 1 // table index
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add \tmp2, \tbl, #PAGE_SIZE
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orr \tmp2, \tmp2, #PMD_TYPE_TABLE // address of next table and entry type
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str \tmp2, [\tbl, \tmp1, lsl #3]
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add \tbl, \tbl, #PAGE_SIZE // next level table page
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.endm
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/*
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* Macro to populate the PGD (and possibily PUD) for the corresponding
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* block entry in the next level (tbl) for the given virtual address.
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*
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* Preserves: tbl, next, virt
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* Corrupts: tmp1, tmp2
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*/
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.macro create_pgd_entry, tbl, virt, tmp1, tmp2
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create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2
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#if SWAPPER_PGTABLE_LEVELS > 3
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create_table_entry \tbl, \virt, PUD_SHIFT, PTRS_PER_PUD, \tmp1, \tmp2
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#endif
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#if SWAPPER_PGTABLE_LEVELS > 2
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create_table_entry \tbl, \virt, SWAPPER_TABLE_SHIFT, PTRS_PER_PTE, \tmp1, \tmp2
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#endif
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.endm
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/*
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* Macro to populate block entries in the page table for the start..end
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* virtual range (inclusive).
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*
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* Preserves: tbl, flags
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* Corrupts: phys, start, end, pstate
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*/
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.macro create_block_map, tbl, flags, phys, start, end
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lsr \phys, \phys, #SWAPPER_BLOCK_SHIFT
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lsr \start, \start, #SWAPPER_BLOCK_SHIFT
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and \start, \start, #PTRS_PER_PTE - 1 // table index
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orr \phys, \flags, \phys, lsl #SWAPPER_BLOCK_SHIFT // table entry
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lsr \end, \end, #SWAPPER_BLOCK_SHIFT
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and \end, \end, #PTRS_PER_PTE - 1 // table end index
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9999: str \phys, [\tbl, \start, lsl #3] // store the entry
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add \start, \start, #1 // next entry
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add \phys, \phys, #SWAPPER_BLOCK_SIZE // next block
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cmp \start, \end
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b.ls 9999b
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.endm
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/*
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* Setup the initial page tables. We only setup the barest amount which is
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* required to get the kernel running. The following sections are required:
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* - identity mapping to enable the MMU (low address, TTBR0)
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* - first few MB of the kernel linear mapping to jump to once the MMU has
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* been enabled
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*/
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__create_page_tables:
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adrp x25, idmap_pg_dir
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adrp x26, swapper_pg_dir
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mov x28, lr
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/*
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* Invalidate the idmap and swapper page tables to avoid potential
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* dirty cache lines being evicted.
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*/
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mov x0, x25
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add x1, x26, #SWAPPER_DIR_SIZE
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bl __inval_cache_range
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/*
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* Clear the idmap and swapper page tables.
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*/
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mov x0, x25
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add x6, x26, #SWAPPER_DIR_SIZE
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1: stp xzr, xzr, [x0], #16
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stp xzr, xzr, [x0], #16
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stp xzr, xzr, [x0], #16
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stp xzr, xzr, [x0], #16
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cmp x0, x6
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b.lo 1b
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ldr x7, =SWAPPER_MM_MMUFLAGS
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/*
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* Create the identity mapping.
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*/
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mov x0, x25 // idmap_pg_dir
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adrp x3, __idmap_text_start // __pa(__idmap_text_start)
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#ifndef CONFIG_ARM64_VA_BITS_48
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#define EXTRA_SHIFT (PGDIR_SHIFT + PAGE_SHIFT - 3)
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#define EXTRA_PTRS (1 << (48 - EXTRA_SHIFT))
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/*
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* If VA_BITS < 48, it may be too small to allow for an ID mapping to be
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* created that covers system RAM if that is located sufficiently high
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* in the physical address space. So for the ID map, use an extended
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* virtual range in that case, by configuring an additional translation
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* level.
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* First, we have to verify our assumption that the current value of
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* VA_BITS was chosen such that all translation levels are fully
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* utilised, and that lowering T0SZ will always result in an additional
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* translation level to be configured.
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*/
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#if VA_BITS != EXTRA_SHIFT
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#error "Mismatch between VA_BITS and page size/number of translation levels"
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#endif
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/*
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* Calculate the maximum allowed value for TCR_EL1.T0SZ so that the
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* entire ID map region can be mapped. As T0SZ == (64 - #bits used),
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* this number conveniently equals the number of leading zeroes in
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* the physical address of __idmap_text_end.
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*/
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adrp x5, __idmap_text_end
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clz x5, x5
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cmp x5, TCR_T0SZ(VA_BITS) // default T0SZ small enough?
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b.ge 1f // .. then skip additional level
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adr_l x6, idmap_t0sz
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str x5, [x6]
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dmb sy
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dc ivac, x6 // Invalidate potentially stale cache line
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create_table_entry x0, x3, EXTRA_SHIFT, EXTRA_PTRS, x5, x6
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1:
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#endif
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create_pgd_entry x0, x3, x5, x6
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mov x5, x3 // __pa(__idmap_text_start)
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adr_l x6, __idmap_text_end // __pa(__idmap_text_end)
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create_block_map x0, x7, x3, x5, x6
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/*
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* Map the kernel image (starting with PHYS_OFFSET).
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*/
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mov x0, x26 // swapper_pg_dir
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ldr x5, =KIMAGE_VADDR
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add x5, x5, x23 // add KASLR displacement
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create_pgd_entry x0, x5, x3, x6
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ldr w6, =kernel_img_size
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add x6, x6, x5
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mov x3, x24 // phys offset
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create_block_map x0, x7, x3, x5, x6
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/*
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* Since the page tables have been populated with non-cacheable
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* accesses (MMU disabled), invalidate the idmap and swapper page
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* tables again to remove any speculatively loaded cache lines.
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*/
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mov x0, x25
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add x1, x26, #SWAPPER_DIR_SIZE
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dmb sy
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bl __inval_cache_range
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ret x28
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ENDPROC(__create_page_tables)
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.ltorg
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/*
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* The following fragment of code is executed with the MMU enabled.
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*/
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.set initial_sp, init_thread_union + THREAD_START_SP
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__mmap_switched:
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mov x28, lr // preserve LR
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adr_l x8, vectors // load VBAR_EL1 with virtual
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msr vbar_el1, x8 // vector table address
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isb
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// Clear BSS
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adr_l x0, __bss_start
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mov x1, xzr
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adr_l x2, __bss_stop
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sub x2, x2, x0
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bl __pi_memset
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dsb ishst // Make zero page visible to PTW
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#ifdef CONFIG_RELOCATABLE
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/*
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* Iterate over each entry in the relocation table, and apply the
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* relocations in place.
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*/
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adr_l x8, __dynsym_start // start of symbol table
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adr_l x9, __reloc_start // start of reloc table
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adr_l x10, __reloc_end // end of reloc table
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0: cmp x9, x10
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b.hs 2f
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ldp x11, x12, [x9], #24
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ldr x13, [x9, #-8]
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cmp w12, #R_AARCH64_RELATIVE
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b.ne 1f
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add x13, x13, x23 // relocate
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str x13, [x11, x23]
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b 0b
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1: cmp w12, #R_AARCH64_ABS64
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b.ne 0b
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add x12, x12, x12, lsl #1 // symtab offset: 24x top word
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add x12, x8, x12, lsr #(32 - 3) // ... shifted into bottom word
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ldrsh w14, [x12, #6] // Elf64_Sym::st_shndx
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ldr x15, [x12, #8] // Elf64_Sym::st_value
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cmp w14, #-0xf // SHN_ABS (0xfff1) ?
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add x14, x15, x23 // relocate
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csel x15, x14, x15, ne
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add x15, x13, x15
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str x15, [x11, x23]
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b 0b
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2: adr_l x8, kimage_vaddr // make relocated kimage_vaddr
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dc cvac, x8 // value visible to secondaries
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dsb sy // with MMU off
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#endif
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adr_l sp, initial_sp, x4
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mov x4, sp
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|
and x4, x4, #~(THREAD_SIZE - 1)
|
|
msr sp_el0, x4 // Save thread_info
|
|
str_l x21, __fdt_pointer, x5 // Save FDT pointer
|
|
|
|
ldr_l x4, kimage_vaddr // Save the offset between
|
|
sub x4, x4, x24 // the kernel virtual and
|
|
str_l x4, kimage_voffset, x5 // physical mappings
|
|
|
|
mov x29, #0
|
|
#ifdef CONFIG_KASAN
|
|
bl kasan_early_init
|
|
#endif
|
|
#ifdef CONFIG_RANDOMIZE_BASE
|
|
cbnz x23, 0f // already running randomized?
|
|
mov x0, x21 // pass FDT address in x0
|
|
bl kaslr_early_init // parse FDT for KASLR options
|
|
cbz x0, 0f // KASLR disabled? just proceed
|
|
mov x23, x0 // record KASLR offset
|
|
ret x28 // we must enable KASLR, return
|
|
// to __enable_mmu()
|
|
0:
|
|
#endif
|
|
b start_kernel
|
|
ENDPROC(__mmap_switched)
|
|
|
|
/*
|
|
* end early head section, begin head code that is also used for
|
|
* hotplug and needs to have the same protections as the text region
|
|
*/
|
|
.section ".text","ax"
|
|
|
|
ENTRY(kimage_vaddr)
|
|
.quad _text - TEXT_OFFSET
|
|
|
|
/*
|
|
* If we're fortunate enough to boot at EL2, ensure that the world is
|
|
* sane before dropping to EL1.
|
|
*
|
|
* Returns either BOOT_CPU_MODE_EL1 or BOOT_CPU_MODE_EL2 in x20 if
|
|
* booted in EL1 or EL2 respectively.
|
|
*/
|
|
ENTRY(el2_setup)
|
|
mrs x0, CurrentEL
|
|
cmp x0, #CurrentEL_EL2
|
|
b.ne 1f
|
|
mrs x0, sctlr_el2
|
|
CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2
|
|
CPU_LE( bic x0, x0, #(1 << 25) ) // Clear the EE bit for EL2
|
|
msr sctlr_el2, x0
|
|
b 2f
|
|
1: mrs x0, sctlr_el1
|
|
CPU_BE( orr x0, x0, #(3 << 24) ) // Set the EE and E0E bits for EL1
|
|
CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
|
|
msr sctlr_el1, x0
|
|
mov w20, #BOOT_CPU_MODE_EL1 // This cpu booted in EL1
|
|
isb
|
|
ret
|
|
|
|
2:
|
|
#ifdef CONFIG_ARM64_VHE
|
|
/*
|
|
* Check for VHE being present. For the rest of the EL2 setup,
|
|
* x2 being non-zero indicates that we do have VHE, and that the
|
|
* kernel is intended to run at EL2.
|
|
*/
|
|
mrs x2, id_aa64mmfr1_el1
|
|
ubfx x2, x2, #8, #4
|
|
#else
|
|
mov x2, xzr
|
|
#endif
|
|
|
|
/* Hyp configuration. */
|
|
mov x0, #HCR_RW // 64-bit EL1
|
|
cbz x2, set_hcr
|
|
orr x0, x0, #HCR_TGE // Enable Host Extensions
|
|
orr x0, x0, #HCR_E2H
|
|
set_hcr:
|
|
msr hcr_el2, x0
|
|
isb
|
|
|
|
/* Generic timers. */
|
|
mrs x0, cnthctl_el2
|
|
orr x0, x0, #3 // Enable EL1 physical timers
|
|
msr cnthctl_el2, x0
|
|
msr cntvoff_el2, xzr // Clear virtual offset
|
|
|
|
#ifdef CONFIG_ARM_GIC_V3
|
|
/* GICv3 system register access */
|
|
mrs x0, id_aa64pfr0_el1
|
|
ubfx x0, x0, #24, #4
|
|
cmp x0, #1
|
|
b.ne 3f
|
|
|
|
mrs_s x0, ICC_SRE_EL2
|
|
orr x0, x0, #ICC_SRE_EL2_SRE // Set ICC_SRE_EL2.SRE==1
|
|
orr x0, x0, #ICC_SRE_EL2_ENABLE // Set ICC_SRE_EL2.Enable==1
|
|
msr_s ICC_SRE_EL2, x0
|
|
isb // Make sure SRE is now set
|
|
mrs_s x0, ICC_SRE_EL2 // Read SRE back,
|
|
tbz x0, #0, 3f // and check that it sticks
|
|
msr_s ICH_HCR_EL2, xzr // Reset ICC_HCR_EL2 to defaults
|
|
|
|
3:
|
|
#endif
|
|
|
|
/* Populate ID registers. */
|
|
mrs x0, midr_el1
|
|
mrs x1, mpidr_el1
|
|
msr vpidr_el2, x0
|
|
msr vmpidr_el2, x1
|
|
|
|
/* sctlr_el1 */
|
|
mov x0, #0x0800 // Set/clear RES{1,0} bits
|
|
CPU_BE( movk x0, #0x33d0, lsl #16 ) // Set EE and E0E on BE systems
|
|
CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
|
|
msr sctlr_el1, x0
|
|
|
|
/* Coprocessor traps. */
|
|
mov x0, #0x33ff
|
|
msr cptr_el2, x0 // Disable copro. traps to EL2
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
msr hstr_el2, xzr // Disable CP15 traps to EL2
|
|
#endif
|
|
|
|
/* EL2 debug */
|
|
mrs x0, id_aa64dfr0_el1 // Check ID_AA64DFR0_EL1 PMUVer
|
|
sbfx x0, x0, #8, #4
|
|
cmp x0, #1
|
|
b.lt 4f // Skip if no PMU present
|
|
mrs x0, pmcr_el0 // Disable debug access traps
|
|
ubfx x0, x0, #11, #5 // to EL2 and allow access to
|
|
msr mdcr_el2, x0 // all PMU counters from EL1
|
|
4:
|
|
|
|
/* Stage-2 translation */
|
|
msr vttbr_el2, xzr
|
|
|
|
cbz x2, install_el2_stub
|
|
|
|
mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2
|
|
isb
|
|
ret
|
|
|
|
install_el2_stub:
|
|
/* Hypervisor stub */
|
|
adrp x0, __hyp_stub_vectors
|
|
add x0, x0, #:lo12:__hyp_stub_vectors
|
|
msr vbar_el2, x0
|
|
|
|
/* spsr */
|
|
mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
|
|
PSR_MODE_EL1h)
|
|
msr spsr_el2, x0
|
|
msr elr_el2, lr
|
|
mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2
|
|
eret
|
|
ENDPROC(el2_setup)
|
|
|
|
/*
|
|
* Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
|
|
* in x20. See arch/arm64/include/asm/virt.h for more info.
|
|
*/
|
|
ENTRY(set_cpu_boot_mode_flag)
|
|
adr_l x1, __boot_cpu_mode
|
|
cmp w20, #BOOT_CPU_MODE_EL2
|
|
b.ne 1f
|
|
add x1, x1, #4
|
|
1: str w20, [x1] // This CPU has booted in EL1
|
|
dmb sy
|
|
dc ivac, x1 // Invalidate potentially stale cache line
|
|
ret
|
|
ENDPROC(set_cpu_boot_mode_flag)
|
|
|
|
/*
|
|
* We need to find out the CPU boot mode long after boot, so we need to
|
|
* store it in a writable variable.
|
|
*
|
|
* This is not in .bss, because we set it sufficiently early that the boot-time
|
|
* zeroing of .bss would clobber it.
|
|
*/
|
|
.pushsection .data..cacheline_aligned
|
|
.align L1_CACHE_SHIFT
|
|
ENTRY(__boot_cpu_mode)
|
|
.long BOOT_CPU_MODE_EL2
|
|
.long BOOT_CPU_MODE_EL1
|
|
.popsection
|
|
|
|
/*
|
|
* This provides a "holding pen" for platforms to hold all secondary
|
|
* cores are held until we're ready for them to initialise.
|
|
*/
|
|
ENTRY(secondary_holding_pen)
|
|
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
|
|
bl set_cpu_boot_mode_flag
|
|
mrs x0, mpidr_el1
|
|
ldr x1, =MPIDR_HWID_BITMASK
|
|
and x0, x0, x1
|
|
adr_l x3, secondary_holding_pen_release
|
|
pen: ldr x4, [x3]
|
|
cmp x4, x0
|
|
b.eq secondary_startup
|
|
wfe
|
|
b pen
|
|
ENDPROC(secondary_holding_pen)
|
|
|
|
/*
|
|
* Secondary entry point that jumps straight into the kernel. Only to
|
|
* be used where CPUs are brought online dynamically by the kernel.
|
|
*/
|
|
ENTRY(secondary_entry)
|
|
bl el2_setup // Drop to EL1
|
|
bl set_cpu_boot_mode_flag
|
|
b secondary_startup
|
|
ENDPROC(secondary_entry)
|
|
|
|
ENTRY(secondary_startup)
|
|
/*
|
|
* Common entry point for secondary CPUs.
|
|
*/
|
|
adrp x25, idmap_pg_dir
|
|
adrp x26, swapper_pg_dir
|
|
bl __cpu_setup // initialise processor
|
|
|
|
ldr x8, kimage_vaddr
|
|
ldr w9, 0f
|
|
sub x27, x8, w9, sxtw // address to jump to after enabling the MMU
|
|
b __enable_mmu
|
|
ENDPROC(secondary_startup)
|
|
0: .long (_text - TEXT_OFFSET) - __secondary_switched
|
|
|
|
ENTRY(__secondary_switched)
|
|
adr_l x5, vectors
|
|
msr vbar_el1, x5
|
|
isb
|
|
|
|
adr_l x0, secondary_data
|
|
ldr x0, [x0, #CPU_BOOT_STACK] // get secondary_data.stack
|
|
mov sp, x0
|
|
and x0, x0, #~(THREAD_SIZE - 1)
|
|
msr sp_el0, x0 // save thread_info
|
|
mov x29, #0
|
|
b secondary_start_kernel
|
|
ENDPROC(__secondary_switched)
|
|
|
|
/*
|
|
* The booting CPU updates the failed status @__early_cpu_boot_status,
|
|
* with MMU turned off.
|
|
*
|
|
* update_early_cpu_boot_status tmp, status
|
|
* - Corrupts tmp1, tmp2
|
|
* - Writes 'status' to __early_cpu_boot_status and makes sure
|
|
* it is committed to memory.
|
|
*/
|
|
|
|
.macro update_early_cpu_boot_status status, tmp1, tmp2
|
|
mov \tmp2, #\status
|
|
str_l \tmp2, __early_cpu_boot_status, \tmp1
|
|
dmb sy
|
|
dc ivac, \tmp1 // Invalidate potentially stale cache line
|
|
.endm
|
|
|
|
.pushsection .data..cacheline_aligned
|
|
.align L1_CACHE_SHIFT
|
|
ENTRY(__early_cpu_boot_status)
|
|
.long 0
|
|
.popsection
|
|
|
|
/*
|
|
* Enable the MMU.
|
|
*
|
|
* x0 = SCTLR_EL1 value for turning on the MMU.
|
|
* x27 = *virtual* address to jump to upon completion
|
|
*
|
|
* Other registers depend on the function called upon completion.
|
|
*
|
|
* Checks if the selected granule size is supported by the CPU.
|
|
* If it isn't, park the CPU
|
|
*/
|
|
.section ".idmap.text", "ax"
|
|
__enable_mmu:
|
|
mrs x22, sctlr_el1 // preserve old SCTLR_EL1 value
|
|
mrs x1, ID_AA64MMFR0_EL1
|
|
ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4
|
|
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
|
|
b.ne __no_granule_support
|
|
update_early_cpu_boot_status 0, x1, x2
|
|
msr ttbr0_el1, x25 // load TTBR0
|
|
msr ttbr1_el1, x26 // load TTBR1
|
|
isb
|
|
msr sctlr_el1, x0
|
|
isb
|
|
/*
|
|
* Invalidate the local I-cache so that any instructions fetched
|
|
* speculatively from the PoC are discarded, since they may have
|
|
* been dynamically patched at the PoU.
|
|
*/
|
|
ic iallu
|
|
dsb nsh
|
|
isb
|
|
#ifdef CONFIG_RANDOMIZE_BASE
|
|
mov x19, x0 // preserve new SCTLR_EL1 value
|
|
blr x27
|
|
|
|
/*
|
|
* If we return here, we have a KASLR displacement in x23 which we need
|
|
* to take into account by discarding the current kernel mapping and
|
|
* creating a new one.
|
|
*/
|
|
msr sctlr_el1, x22 // disable the MMU
|
|
isb
|
|
bl __create_page_tables // recreate kernel mapping
|
|
|
|
msr sctlr_el1, x19 // re-enable the MMU
|
|
isb
|
|
ic iallu // flush instructions fetched
|
|
dsb nsh // via old mapping
|
|
isb
|
|
add x27, x27, x23 // relocated __mmap_switched
|
|
#endif
|
|
br x27
|
|
ENDPROC(__enable_mmu)
|
|
|
|
__no_granule_support:
|
|
/* Indicate that this CPU can't boot and is stuck in the kernel */
|
|
update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x1, x2
|
|
1:
|
|
wfe
|
|
wfi
|
|
b 1b
|
|
ENDPROC(__no_granule_support)
|