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SubjectRe: [PATCH 5/5] x86: if kernel .text .data .bss are not marked as E820_RAM, complain and fix
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On Fri, Aug 24, 2012 at 4:55 PM, Jacob Shin <jacob.shin@amd.com> wrote:
> 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 | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 4217fb4..b84aceb5 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -926,6 +926,21 @@ 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, bss_resource.end, E820_RAM)) {
> + pr_warn(".text .data .bss are not marked as E820_RAM!\n");
> +
> + e820_add_region(code_resource.start,
> + bss_resource.end - code_resource.start + 1,
> + E820_RAM);
> + sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

this sanitze_e820_map could be spared. trim_bios_range will
that always.

> + }
> +
> trim_bios_range();
> #ifdef CONFIG_X86_32
> if (ppro_with_ram_bug()) {

also should use brk_limit instead of bss_resource.end. aka need to
keep the map for brk area.

Thanks

Yinghai


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