• Antonio Nino Diaz's avatar
    Replace magic numbers in linkerscripts by PAGE_SIZE · a2aedac2
    Antonio Nino Diaz authored
    
    When defining different sections in linker scripts it is needed to align
    them to multiples of the page size. In most linker scripts this is done
    by aligning to the hardcoded value 4096 instead of PAGE_SIZE.
    
    This may be confusing when taking a look at all the codebase, as 4096
    is used in some parts that aren't meant to be a multiple of the page
    size.
    
    Change-Id: I36c6f461c7782437a58d13d37ec8b822a1663ec1
    Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
    a2aedac2
bl2.ld.S 4.01 KB
/*
 * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <platform_def.h>
#include <xlat_tables_defs.h>

OUTPUT_FORMAT(PLATFORM_LINKER_FORMAT)
OUTPUT_ARCH(PLATFORM_LINKER_ARCH)
ENTRY(bl2_entrypoint)

MEMORY {
    RAM (rwx): ORIGIN = BL2_BASE, LENGTH = BL2_LIMIT - BL2_BASE
}


SECTIONS
{
    . = BL2_BASE;
    ASSERT(. == ALIGN(PAGE_SIZE),
           "BL2_BASE address is not aligned on a page boundary.")

#if SEPARATE_CODE_AND_RODATA
    .text . : {
        __TEXT_START__ = .;
        *bl2_entrypoint.o(.text*)
        *(.text*)
        *(.vectors)
        . = NEXT(PAGE_SIZE);
        __TEXT_END__ = .;
     } >RAM

    .rodata . : {
        __RODATA_START__ = .;
        *(.rodata*)

        /* Ensure 8-byte alignment for descriptors and ensure inclusion */
        . = ALIGN(8);
        __PARSER_LIB_DESCS_START__ = .;
        KEEP(*(.img_parser_lib_descs))
        __PARSER_LIB_DESCS_END__ = .;

        . = NEXT(PAGE_SIZE);
        __RODATA_END__ = .;
    } >RAM
#else
    ro . : {
        __RO_START__ = .;
        *bl2_entrypoint.o(.text*)
        *(.text*)
        *(.rodata*)

        /* Ensure 8-byte alignment for descriptors and ensure inclusion */
        . = ALIGN(8);
        __PARSER_LIB_DESCS_START__ = .;
        KEEP(*(.img_parser_lib_descs))
        __PARSER_LIB_DESCS_END__ = .;

        *(.vectors)
        __RO_END_UNALIGNED__ = .;
        /*
         * Memory page(s) mapped to this section will be marked as
         * read-only, executable.  No RW data from the next section must
         * creep in.  Ensure the rest of the current memory page is unused.
         */
        . = NEXT(PAGE_SIZE);
        __RO_END__ = .;
    } >RAM
#endif

    /*
     * Define a linker symbol to mark start of the RW memory area for this
     * image.
     */
    __RW_START__ = . ;

    /*
     * .data must be placed at a lower address than the stacks if the stack
     * protector is enabled. Alternatively, the .data.stack_protector_canary
     * section can be placed independently of the main .data section.
     */
    .data . : {
        __DATA_START__ = .;
        *(.data*)
        __DATA_END__ = .;
    } >RAM

    stacks (NOLOAD) : {
        __STACKS_START__ = .;
        *(tzfw_normal_stacks)
        __STACKS_END__ = .;
    } >RAM

    /*
     * The .bss section gets initialised to 0 at runtime.
     * Its base address should be 16-byte aligned for better performance of the
     * zero-initialization code.
     */
    .bss : ALIGN(16) {
        __BSS_START__ = .;
        *(SORT_BY_ALIGNMENT(.bss*))
        *(COMMON)
        __BSS_END__ = .;
    } >RAM

    /*
     * The xlat_table section is for full, aligned page tables (4K).
     * Removing them from .bss avoids forcing 4K alignment on
     * the .bss section and eliminates the unecessary zero init
     */
    xlat_table (NOLOAD) : {
        *(xlat_table)
    } >RAM

#if USE_COHERENT_MEM
    /*
     * The base address of the coherent memory section must be page-aligned (4K)
     * to guarantee that the coherent data are stored on their own pages and
     * are not mixed with normal data.  This is required to set up the correct
     * memory attributes for the coherent data page tables.
     */
    coherent_ram (NOLOAD) : ALIGN(PAGE_SIZE) {
        __COHERENT_RAM_START__ = .;
        *(tzfw_coherent_mem)
        __COHERENT_RAM_END_UNALIGNED__ = .;
        /*
         * Memory page(s) mapped to this section will be marked
         * as device memory.  No other unexpected data must creep in.
         * Ensure the rest of the current memory page is unused.
         */
        . = NEXT(PAGE_SIZE);
        __COHERENT_RAM_END__ = .;
    } >RAM
#endif

    /*
     * Define a linker symbol to mark end of the RW memory area for this
     * image.
     */
    __RW_END__ = .;
    __BL2_END__ = .;

    __BSS_SIZE__ = SIZEOF(.bss);

#if USE_COHERENT_MEM
    __COHERENT_RAM_UNALIGNED_SIZE__ =
        __COHERENT_RAM_END_UNALIGNED__ - __COHERENT_RAM_START__;
#endif

    ASSERT(. <= BL2_LIMIT, "BL2 image has exceeded its limit.")
}