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    Subject[PATCH 6/6] x86: if kernel .text .data .bss are not marked as E820_RAM, complain and fix
    Date
    There could be cases where user supplied memmap=exactmap memory
    mappings do not mark the region where the kernel .text .data and
    .bss reside as E820_RAM, as reported here:

    https://lkml.org/lkml/2012/8/14/86

    Handle it by complaining, and adding the range back into the e820.

    Signed-off-by: Jacob Shin <jacob.shin@amd.com>
    ---
    arch/x86/kernel/setup.c | 14 ++++++++++++++
    1 file changed, 14 insertions(+)

    diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
    index a2e392e..68f82d2 100644
    --- a/arch/x86/kernel/setup.c
    +++ b/arch/x86/kernel/setup.c
    @@ -913,6 +913,20 @@ void __init setup_arch(char **cmdline_p)
    insert_resource(&iomem_resource, &data_resource);
    insert_resource(&iomem_resource, &bss_resource);

    + /*
    + * Complain if .text .data and .bss are not marked as E820_RAM and
    + * attempt to fix it by adding the range. We may have a confused BIOS,
    + * or the user may have incorrectly supplied it via memmap=exactmap. If
    + * we really are running on top non-RAM, we will crash later anyways.
    + */
    + if (!e820_all_mapped(code_resource.start, __pa(__brk_limit), E820_RAM)) {
    + pr_warn(".text .data .bss are not marked as E820_RAM!\n");
    +
    + e820_add_region(code_resource.start,
    + __pa(__brk_limit) - code_resource.start + 1,
    + E820_RAM);
    + }
    +
    trim_bios_range();
    #ifdef CONFIG_X86_32
    if (ppro_with_ram_bug()) {
    --
    1.7.9.5



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