• Achin Gupta's avatar
    Make generic code work in presence of system caches · 54dc71e7
    Achin Gupta authored
    On the ARMv8 architecture, cache maintenance operations by set/way on the last
    level of integrated cache do not affect the system cache. This means that such a
    flush or clean operation could result in the data being pushed out to the system
    cache rather than main memory. Another CPU could access this data before it
    enables its data cache or MMU. Such accesses could be serviced from the main
    memory instead of the system cache. If the data in the sysem cache has not yet
    been flushed or evicted to main memory then there could be a loss of
    coherency. The only mechanism to guarantee that the main memory will be updated
    is to use cache maintenance operations to the PoC by MVA(See section D3.4.11
    (System level caches) of ARMv8-A Reference Manual (Issue A.g/ARM DDI0487A.G).
    
    This patch removes the reliance of Trusted Firmware on the flush by set/way
    operation to ensure visibility of data in the main memory. Cache maintenance
    operations by MVA are now used instea...
    54dc71e7
bl2.ld.S 4.5 KB
/*
 * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of ARM nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <platform_def.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(4096),
           "BL2_BASE address is not aligned on a page boundary.")

    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(4096);
        __RO_END__ = .;
    } >RAM

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

    .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 must be 16-byte aligned.
     */
    .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(4096) {
        __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(4096);
        __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.")
}