root/arch/arm/kernel/vmlinux-xip.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>
 */

/* No __ro_after_init data in the .rodata section - which will always be ro */
#define RO_AFTER_INIT_DATA

#include <linux/sizes.h>

#include <asm/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/mpu.h>

OUTPUT_ARCH(arm)
ENTRY(stext)

#ifndef __ARMEB__
jiffies = jiffies_64;
#else
jiffies = jiffies_64 + 4;
#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.
         *
         * unwind exit sections must be discarded before the rest of the
         * unwind sections get included.
         */
        /DISCARD/ : {
                ARM_DISCARD
                *(.alt.smp.init)
                *(.pv_table)
#ifndef CONFIG_ARM_UNWIND
                *(.ARM.exidx) *(.ARM.exidx.*)
                *(.ARM.extab) *(.ARM.extab.*)
#endif
        }

        . = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
        _xiprom = .;                    /* XIP ROM area to be mapped */

        .head.text : {
                _text = .;
                HEAD_TEXT
        }

        .text : {                       /* Real text segment            */
                _stext = .;             /* Text and read-only data      */
                ARM_TEXT
        }

        RO_DATA(PAGE_SIZE)

        . = ALIGN(4);
        __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
                __start___ex_table = .;
                ARM_MMU_KEEP(*(__ex_table))
                __stop___ex_table = .;
        }

#ifdef CONFIG_ARM_UNWIND
        ARM_UNWIND_SECTIONS
#endif

        _etext = .;                     /* End of text and rodata section */

        ARM_VECTORS
        INIT_TEXT_SECTION(8)
        .exit.text : {
                ARM_EXIT_KEEP(EXIT_TEXT)
        }
        .init.proc.info : {
                ARM_CPU_DISCARD(PROC_INFO)
        }
        .init.arch.info : {
                __arch_info_begin = .;
                KEEP(*(.arch.info.init))
                __arch_info_end = .;
        }
        .init.tagtable : {
                __tagtable_begin = .;
                *(.taglist.init)
                __tagtable_end = .;
        }
        .init.rodata : {
                INIT_SETUP(16)
                INIT_CALLS
                CON_INITCALL
                INIT_RAM_FS
        }

#ifdef CONFIG_ARM_MPU
        . = ALIGN(SZ_128K);
#endif
        _exiprom = .;                   /* End of XIP ROM area */

/*
 * From this point, stuff is considered writable and will be copied to RAM
 */
        __data_loc = ALIGN(4);          /* location in file */
        . = PAGE_OFFSET + TEXT_OFFSET;  /* location in memory */
#undef LOAD_OFFSET
#define LOAD_OFFSET (PAGE_OFFSET + TEXT_OFFSET - __data_loc)

        . = ALIGN(THREAD_SIZE);
        _sdata = .;
        RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
        .data.ro_after_init : AT(ADDR(.data.ro_after_init) - LOAD_OFFSET) {
                *(.data..ro_after_init)
        }
        _edata = .;

        . = ALIGN(PAGE_SIZE);
        __init_begin = .;
        .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
                INIT_DATA
        }
        .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
                ARM_EXIT_KEEP(EXIT_DATA)
        }
#ifdef CONFIG_SMP
        PERCPU_SECTION(L1_CACHE_BYTES)
#endif

#ifdef CONFIG_HAVE_TCM
        ARM_TCM
#endif

        /*
         * End of copied data. We need a dummy section to get its LMA.
         * Also located before final ALIGN() as trailing padding is not stored
         * in the resulting binary file and useless to copy.
         */
        .data.endmark : AT(ADDR(.data.endmark) - LOAD_OFFSET) { }
        _edata_loc = LOADADDR(.data.endmark);

        . = ALIGN(PAGE_SIZE);
        __init_end = .;

        BSS_SECTION(0, 0, 8)
#ifdef CONFIG_ARM_MPU
        . = ALIGN(PMSAv8_MINALIGN);
#endif
        _end = .;

        STABS_DEBUG
        DWARF_DEBUG
        MODINFO
        ARM_DETAILS

        ARM_ASSERTS
}

/*
 * These must never be empty
 * If you have to comment these two assert statements out, your
 * binutils is too old (for other reasons as well)
 */
ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support")
#ifndef CONFIG_COMPILE_TEST
ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
#endif

#ifdef CONFIG_XIP_DEFLATED_DATA
/*
 * The .bss is used as a stack area for __inflate_kernel_data() whose stack
 * frame is 9568 bytes. Make sure it has extra room left.
 */
ASSERT((_end - __bss_start) >= 12288, ".bss too small for CONFIG_XIP_DEFLATED_DATA")
#endif

#if defined(CONFIG_ARM_MPU) && !defined(CONFIG_COMPILE_TEST)
/*
 * Due to PMSAv7 restriction on base address and size we have to
 * enforce minimal alignment restrictions. It was seen that weaker
 * alignment restriction on _xiprom will likely force XIP address
 * space spawns multiple MPU regions thus it is likely we run in
 * situation when we are reprogramming MPU region we run on with
 * something which doesn't cover reprogramming code itself, so as soon
 * as we update MPU settings we'd immediately try to execute straight
 * from background region which is XN.
 * It seem that alignment in 1M should suit most users.
 * _exiprom is aligned as 1/8 of 1M so can be covered by subregion
 * disable
 */
ASSERT(!(_xiprom & (SZ_1M - 1)), "XIP start address may cause MPU programming issues")
ASSERT(!(_exiprom & (SZ_128K - 1)), "XIP end address may cause MPU programming issues")
#endif