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It seems that LLVM's linker does not correctly handle variable assignments involving section positions that are updated during the SECTIONS parsing. Commitaa69fb62be("arm64/efi: Mark __efistub_stext_offset as an absolute symbol explicitly") ran into this too, but found a different workaround. However, this was not enough, as other variables were also miscalculated which manifested as boot failures under UEFI where __efistub__end was not taking the correct _end value (they should be the same): $ ld.lld -EL -maarch64elf --no-undefined -X -shared \ -Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \ -o vmlinux.lld -T poc.lds --whole-archive vmlinux.o && \ readelf -Ws vmlinux.lld | egrep '\b(__efistub_|)_end\b' 368272: ffff000002218000 0 NOTYPE LOCAL HIDDEN 38 __efistub__end 368322: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 38 _end $ aarch64-linux-gnu-ld.bfd -EL -maarch64elf --no-undefined -X -shared \ -Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \ -o vmlinux.bfd -T poc.lds --whole-archive vmlinux.o && \ readelf -Ws vmlinux.bfd | egrep '\b(__efistub_|)_end\b' 338124: ffff000012318000 0 NOTYPE LOCAL DEFAULT ABS __efistub__end 383812: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 15325 _end To work around this, all of the __efistub_-prefixed variable assignments need to be moved after the linker script's SECTIONS entry. As it turns out, this also solves the problem fixed in commitaa69fb62be, so those changes are reverted here. Link: https://github.com/ClangBuiltLinux/linux/issues/634 Link: https://bugs.llvm.org/show_bug.cgi?id=42990 Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Will Deacon <will@kernel.org>
279 lines
6.2 KiB
ArmAsm
279 lines
6.2 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* ld script to make ARM Linux kernel
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* taken from the i386 version by Russell King
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* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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*/
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/cache.h>
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#include <asm/kernel-pgtable.h>
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#include <asm/thread_info.h>
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#include <asm/memory.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include "image.h"
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/* .exit.text needed in case of alternative patching */
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#define ARM_EXIT_KEEP(x) x
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#define ARM_EXIT_DISCARD(x)
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OUTPUT_ARCH(aarch64)
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ENTRY(_text)
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jiffies = jiffies_64;
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#define HYPERVISOR_TEXT \
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/* \
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* Align to 4 KB so that \
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* a) the HYP vector table is at its minimum \
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* alignment of 2048 bytes \
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* b) the HYP init code will not cross a page \
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* boundary if its size does not exceed \
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* 4 KB (see related ASSERT() below) \
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*/ \
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. = ALIGN(SZ_4K); \
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__hyp_idmap_text_start = .; \
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*(.hyp.idmap.text) \
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__hyp_idmap_text_end = .; \
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__hyp_text_start = .; \
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*(.hyp.text) \
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__hyp_text_end = .;
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#define IDMAP_TEXT \
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. = ALIGN(SZ_4K); \
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__idmap_text_start = .; \
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*(.idmap.text) \
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__idmap_text_end = .;
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#ifdef CONFIG_HIBERNATION
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#define HIBERNATE_TEXT \
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. = ALIGN(SZ_4K); \
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__hibernate_exit_text_start = .; \
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*(.hibernate_exit.text) \
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__hibernate_exit_text_end = .;
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#else
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#define HIBERNATE_TEXT
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#endif
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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
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#define TRAMP_TEXT \
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. = ALIGN(PAGE_SIZE); \
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__entry_tramp_text_start = .; \
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*(.entry.tramp.text) \
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. = ALIGN(PAGE_SIZE); \
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__entry_tramp_text_end = .;
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#else
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#define TRAMP_TEXT
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#endif
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/*
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* The size of the PE/COFF section that covers the kernel image, which
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* runs from stext to _edata, must be a round multiple of the PE/COFF
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* FileAlignment, which we set to its minimum value of 0x200. 'stext'
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* itself is 4 KB aligned, so padding out _edata to a 0x200 aligned
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* boundary should be sufficient.
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*/
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PECOFF_FILE_ALIGNMENT = 0x200;
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#ifdef CONFIG_EFI
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#define PECOFF_EDATA_PADDING \
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.pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); }
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#else
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#define PECOFF_EDATA_PADDING
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#endif
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SECTIONS
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{
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/*
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* XXX: The linker does not define how output sections are
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* assigned to input sections when there are multiple statements
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* matching the same input section name. There is no documented
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* order of matching.
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*/
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/DISCARD/ : {
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ARM_EXIT_DISCARD(EXIT_TEXT)
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ARM_EXIT_DISCARD(EXIT_DATA)
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EXIT_CALL
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*(.discard)
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*(.discard.*)
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*(.interp .dynamic)
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*(.dynsym .dynstr .hash .gnu.hash)
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*(.eh_frame)
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}
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. = KIMAGE_VADDR + TEXT_OFFSET;
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.head.text : {
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_text = .;
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HEAD_TEXT
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}
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.text : { /* Real text segment */
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_stext = .; /* Text and read-only data */
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__exception_text_start = .;
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*(.exception.text)
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__exception_text_end = .;
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IRQENTRY_TEXT
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SOFTIRQENTRY_TEXT
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ENTRY_TEXT
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TEXT_TEXT
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SCHED_TEXT
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CPUIDLE_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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HYPERVISOR_TEXT
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IDMAP_TEXT
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HIBERNATE_TEXT
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TRAMP_TEXT
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*(.fixup)
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*(.gnu.warning)
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. = ALIGN(16);
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*(.got) /* Global offset table */
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}
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. = ALIGN(SEGMENT_ALIGN);
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_etext = .; /* End of text section */
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RO_DATA(PAGE_SIZE) /* everything from this point to */
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EXCEPTION_TABLE(8) /* __init_begin will be marked RO NX */
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NOTES
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. = ALIGN(PAGE_SIZE);
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idmap_pg_dir = .;
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. += IDMAP_DIR_SIZE;
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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
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tramp_pg_dir = .;
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. += PAGE_SIZE;
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#endif
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#ifdef CONFIG_ARM64_SW_TTBR0_PAN
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reserved_ttbr0 = .;
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. += RESERVED_TTBR0_SIZE;
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#endif
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swapper_pg_dir = .;
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. += PAGE_SIZE;
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swapper_pg_end = .;
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. = ALIGN(SEGMENT_ALIGN);
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__init_begin = .;
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__inittext_begin = .;
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INIT_TEXT_SECTION(8)
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.exit.text : {
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ARM_EXIT_KEEP(EXIT_TEXT)
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}
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. = ALIGN(4);
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.altinstructions : {
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__alt_instructions = .;
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*(.altinstructions)
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__alt_instructions_end = .;
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}
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.altinstr_replacement : {
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*(.altinstr_replacement)
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}
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. = ALIGN(PAGE_SIZE);
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__inittext_end = .;
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__initdata_begin = .;
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.init.data : {
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INIT_DATA
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INIT_SETUP(16)
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INIT_CALLS
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CON_INITCALL
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INIT_RAM_FS
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*(.init.rodata.* .init.bss) /* from the EFI stub */
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}
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.exit.data : {
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ARM_EXIT_KEEP(EXIT_DATA)
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}
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PERCPU_SECTION(L1_CACHE_BYTES)
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.rela.dyn : ALIGN(8) {
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*(.rela .rela*)
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}
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__rela_offset = ABSOLUTE(ADDR(.rela.dyn) - KIMAGE_VADDR);
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__rela_size = SIZEOF(.rela.dyn);
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#ifdef CONFIG_RELR
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.relr.dyn : ALIGN(8) {
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*(.relr.dyn)
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}
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__relr_offset = ABSOLUTE(ADDR(.relr.dyn) - KIMAGE_VADDR);
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__relr_size = SIZEOF(.relr.dyn);
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#endif
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. = ALIGN(SEGMENT_ALIGN);
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__initdata_end = .;
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__init_end = .;
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_data = .;
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_sdata = .;
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RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
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/*
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* Data written with the MMU off but read with the MMU on requires
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* cache lines to be invalidated, discarding up to a Cache Writeback
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* Granule (CWG) of data from the cache. Keep the section that
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* requires this type of maintenance to be in its own Cache Writeback
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* Granule (CWG) area so the cache maintenance operations don't
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* interfere with adjacent data.
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*/
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.mmuoff.data.write : ALIGN(SZ_2K) {
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__mmuoff_data_start = .;
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*(.mmuoff.data.write)
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}
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. = ALIGN(SZ_2K);
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.mmuoff.data.read : {
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*(.mmuoff.data.read)
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__mmuoff_data_end = .;
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}
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PECOFF_EDATA_PADDING
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__pecoff_data_rawsize = ABSOLUTE(. - __initdata_begin);
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_edata = .;
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BSS_SECTION(0, 0, 0)
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. = ALIGN(PAGE_SIZE);
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init_pg_dir = .;
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. += INIT_DIR_SIZE;
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init_pg_end = .;
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__pecoff_data_size = ABSOLUTE(. - __initdata_begin);
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_end = .;
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STABS_DEBUG
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HEAD_SYMBOLS
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}
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#include "image-vars.h"
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/*
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* The HYP init code and ID map text can't be longer than a page each,
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* and should not cross a page boundary.
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*/
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ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
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"HYP init code too big or misaligned")
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ASSERT(__idmap_text_end - (__idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
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"ID map text too big or misaligned")
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#ifdef CONFIG_HIBERNATION
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ASSERT(__hibernate_exit_text_end - (__hibernate_exit_text_start & ~(SZ_4K - 1))
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<= SZ_4K, "Hibernate exit text too big or misaligned")
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#endif
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#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
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ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
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"Entry trampoline text too big")
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#endif
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/*
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* If padding is applied before .head.text, virt<->phys conversions will fail.
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*/
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ASSERT(_text == (KIMAGE_VADDR + TEXT_OFFSET), "HEAD is misaligned")
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