forked from Minki/linux
9fdc14c55c
As Kees Cook notes in the ARM counterpart of this patch [0]: The _etext position is defined to be the end of the kernel text code, and should not include any part of the data segments. This interferes with things that might check memory ranges and expect executable code up to _etext. In particular, Kees is referring to the HARDENED_USERCOPY patch set [1], which rejects attempts to call copy_to_user() on kernel ranges containing executable code, but does allow access to the .rodata segment. Regardless of whether one may or may not agree with the distinction, it makes sense for _etext to have the same meaning across architectures. So let's put _etext where it belongs, between .text and .rodata, and fix up existing references to use __init_begin instead, which unlike _end_rodata includes the exception and notes sections as well. The _etext references in kaslr.c are left untouched, since its references to [_stext, _etext) are meant to capture potential jump instruction targets, and so disregarding .rodata is actually an improvement here. [0] http://article.gmane.org/gmane.linux.kernel/2245084 [1] http://thread.gmane.org/gmane.linux.kernel.hardened.devel/2502 Reported-by: Kees Cook <keescook@chromium.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
230 lines
5.2 KiB
ArmAsm
230 lines
5.2 KiB
ArmAsm
/*
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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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VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \
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*(.hyp.idmap.text) \
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VMLINUX_SYMBOL(__hyp_idmap_text_end) = .; \
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VMLINUX_SYMBOL(__hyp_text_start) = .; \
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*(.hyp.text) \
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VMLINUX_SYMBOL(__hyp_text_end) = .;
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#define IDMAP_TEXT \
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. = ALIGN(SZ_4K); \
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VMLINUX_SYMBOL(__idmap_text_start) = .; \
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*(.idmap.text) \
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VMLINUX_SYMBOL(__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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VMLINUX_SYMBOL(__hibernate_exit_text_start) = .;\
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*(.hibernate_exit.text) \
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VMLINUX_SYMBOL(__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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/*
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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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#if defined(CONFIG_DEBUG_ALIGN_RODATA)
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/*
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* 4 KB granule: 1 level 2 entry
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* 16 KB granule: 128 level 3 entries, with contiguous bit
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* 64 KB granule: 32 level 3 entries, with contiguous bit
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*/
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#define SEGMENT_ALIGN SZ_2M
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#else
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/*
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* 4 KB granule: 16 level 3 entries, with contiguous bit
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* 16 KB granule: 4 level 3 entries, without contiguous bit
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* 64 KB granule: 1 level 3 entry
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*/
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#define SEGMENT_ALIGN SZ_64K
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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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}
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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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TEXT_TEXT
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SCHED_TEXT
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LOCK_TEXT
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HYPERVISOR_TEXT
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IDMAP_TEXT
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HIBERNATE_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(SEGMENT_ALIGN);
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__init_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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.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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SECURITY_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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. = 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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.rela : ALIGN(8) {
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*(.rela .rela*)
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}
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.dynsym : ALIGN(8) {
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*(.dynsym)
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}
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.dynstr : {
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*(.dynstr)
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}
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.hash : {
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*(.hash)
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}
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__rela_offset = ADDR(.rela) - KIMAGE_VADDR;
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__rela_size = SIZEOF(.rela);
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__dynsym_offset = ADDR(.dynsym) - KIMAGE_VADDR;
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. = ALIGN(SEGMENT_ALIGN);
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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_SIZE)
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PECOFF_EDATA_PADDING
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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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idmap_pg_dir = .;
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. += IDMAP_DIR_SIZE;
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swapper_pg_dir = .;
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. += SWAPPER_DIR_SIZE;
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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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/*
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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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/*
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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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