alistair23-linux/arch/arm64/kernel/vmlinux.lds.S

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * ld script to make ARM Linux kernel
 * taken from the i386 version by Russell King
 * Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 */

#include <asm-generic/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/kernel-pgtable.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/page.h>
#include <asm/pgtable.h>

#include "image.h"

/* .exit.text needed in case of alternative patching */
#define ARM_EXIT_KEEP(x)	x
#define ARM_EXIT_DISCARD(x)

OUTPUT_ARCH(aarch64)
ENTRY(_text)

jiffies = jiffies_64;

#define HYPERVISOR_TEXT					\
	/*						\
	 * Align to 4 KB so that			\
	 * a) the HYP vector table is at its minimum	\
	 *    alignment of 2048 bytes			\
	 * b) the HYP init code will not cross a page	\
	 *    boundary if its size does not exceed	\
	 *    4 KB (see related ASSERT() below)		\
	 */						\
	. = ALIGN(SZ_4K);				\
	__hyp_idmap_text_start = .;			\
	*(.hyp.idmap.text)				\
	__hyp_idmap_text_end = .;			\
	__hyp_text_start = .;				\
	*(.hyp.text)					\
	__hyp_text_end = .;

#define IDMAP_TEXT					\
	. = ALIGN(SZ_4K);				\
	__idmap_text_start = .;				\
	*(.idmap.text)					\
	__idmap_text_end = .;

#ifdef CONFIG_HIBERNATION
#define HIBERNATE_TEXT					\
	. = ALIGN(SZ_4K);				\
	__hibernate_exit_text_start = .;		\
	*(.hibernate_exit.text)				\
	__hibernate_exit_text_end = .;
#else
#define HIBERNATE_TEXT
#endif

#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
#define TRAMP_TEXT					\
	. = ALIGN(PAGE_SIZE);				\
	__entry_tramp_text_start = .;			\
	*(.entry.tramp.text)				\
	. = ALIGN(PAGE_SIZE);				\
	__entry_tramp_text_end = .;
#else
#define TRAMP_TEXT
#endif

/*
 * The size of the PE/COFF section that covers the kernel image, which
 * runs from stext to _edata, must be a round multiple of the PE/COFF
 * FileAlignment, which we set to its minimum value of 0x200. 'stext'
 * itself is 4 KB aligned, so padding out _edata to a 0x200 aligned
 * boundary should be sufficient.
 */
PECOFF_FILE_ALIGNMENT = 0x200;

#ifdef CONFIG_EFI
#define PECOFF_EDATA_PADDING	\
	.pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); }
#else
#define PECOFF_EDATA_PADDING
#endif

SECTIONS
{
	/*
	 * XXX: The linker does not define how output sections are
	 * assigned to input sections when there are multiple statements
	 * matching the same input section name.  There is no documented
	 * order of matching.
	 */
	/DISCARD/ : {
		ARM_EXIT_DISCARD(EXIT_TEXT)
		ARM_EXIT_DISCARD(EXIT_DATA)
		EXIT_CALL
		*(.discard)
		*(.discard.*)
		*(.interp .dynamic)
		*(.dynsym .dynstr .hash .gnu.hash)
		*(.eh_frame)
	}

	. = KIMAGE_VADDR + TEXT_OFFSET;

	.head.text : {
		_text = .;
		HEAD_TEXT
	}
	.text : {			/* Real text segment		*/
		_stext = .;		/* Text and read-only data	*/
			__exception_text_start = .;
			*(.exception.text)
			__exception_text_end = .;
			IRQENTRY_TEXT
			SOFTIRQENTRY_TEXT
			ENTRY_TEXT
			TEXT_TEXT
			SCHED_TEXT
			CPUIDLE_TEXT
			LOCK_TEXT
			KPROBES_TEXT
			HYPERVISOR_TEXT
			IDMAP_TEXT
			HIBERNATE_TEXT
			TRAMP_TEXT
			*(.fixup)
			*(.gnu.warning)
		. = ALIGN(16);
		*(.got)			/* Global offset table		*/
	}

	. = ALIGN(SEGMENT_ALIGN);
	_etext = .;			/* End of text section */

	RO_DATA(PAGE_SIZE)		/* everything from this point to     */
	EXCEPTION_TABLE(8)		/* __init_begin will be marked RO NX */
	NOTES

	. = ALIGN(PAGE_SIZE);
	idmap_pg_dir = .;
	. += IDMAP_DIR_SIZE;

#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
	tramp_pg_dir = .;
	. += PAGE_SIZE;
#endif

#ifdef CONFIG_ARM64_SW_TTBR0_PAN
	reserved_ttbr0 = .;
	. += RESERVED_TTBR0_SIZE;
#endif
	swapper_pg_dir = .;
	. += PAGE_SIZE;
	swapper_pg_end = .;

	. = ALIGN(SEGMENT_ALIGN);
	__init_begin = .;
	__inittext_begin = .;

	INIT_TEXT_SECTION(8)
	.exit.text : {
		ARM_EXIT_KEEP(EXIT_TEXT)
	}

	. = ALIGN(4);
	.altinstructions : {
		__alt_instructions = .;
		*(.altinstructions)
		__alt_instructions_end = .;
	}
	.altinstr_replacement : {
		*(.altinstr_replacement)
	}

	. = ALIGN(PAGE_SIZE);
	__inittext_end = .;
	__initdata_begin = .;

	.init.data : {
		INIT_DATA
		INIT_SETUP(16)
		INIT_CALLS
		CON_INITCALL
		INIT_RAM_FS
		*(.init.rodata.* .init.bss)	/* from the EFI stub */
	}
	.exit.data : {
		ARM_EXIT_KEEP(EXIT_DATA)
	}

	PERCPU_SECTION(L1_CACHE_BYTES)

	.rela.dyn : ALIGN(8) {
		*(.rela .rela*)
	}

	__rela_offset	= ABSOLUTE(ADDR(.rela.dyn) - KIMAGE_VADDR);
	__rela_size	= SIZEOF(.rela.dyn);

	. = ALIGN(SEGMENT_ALIGN);
	__initdata_end = .;
	__init_end = .;

	_data = .;
	_sdata = .;
	RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)

	/*
	 * Data written with the MMU off but read with the MMU on requires
	 * cache lines to be invalidated, discarding up to a Cache Writeback
	 * Granule (CWG) of data from the cache. Keep the section that
	 * requires this type of maintenance to be in its own Cache Writeback
	 * Granule (CWG) area so the cache maintenance operations don't
	 * interfere with adjacent data.
	 */
	.mmuoff.data.write : ALIGN(SZ_2K) {
		__mmuoff_data_start = .;
		*(.mmuoff.data.write)
	}
	. = ALIGN(SZ_2K);
	.mmuoff.data.read : {
		*(.mmuoff.data.read)
		__mmuoff_data_end = .;
	}

	PECOFF_EDATA_PADDING
	__pecoff_data_rawsize = ABSOLUTE(. - __initdata_begin);
	_edata = .;

	BSS_SECTION(0, 0, 0)

	. = ALIGN(PAGE_SIZE);
	init_pg_dir = .;
	. += INIT_DIR_SIZE;
	init_pg_end = .;

	__pecoff_data_size = ABSOLUTE(. - __initdata_begin);
	_end = .;

	STABS_DEBUG

	HEAD_SYMBOLS
}

/*
 * The HYP init code and ID map text can't be longer than a page each,
 * and should not cross a page boundary.
 */
ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
	"HYP init code too big or misaligned")
ASSERT(__idmap_text_end - (__idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K,
	"ID map text too big or misaligned")
#ifdef CONFIG_HIBERNATION
ASSERT(__hibernate_exit_text_end - (__hibernate_exit_text_start & ~(SZ_4K - 1))
	<= SZ_4K, "Hibernate exit text too big or misaligned")
#endif
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
	"Entry trampoline text too big")
#endif
/*
 * If padding is applied before .head.text, virt<->phys conversions will fail.
 */
ASSERT(_text == (KIMAGE_VADDR + TEXT_OFFSET), "HEAD is misaligned")