Re: [PATCH v7 1/3] x86/boot: Add acpitb.c to parse acpi tables

Kees Cook
2018-09-22T15:45:19Z

On Thu, Sep 13, 2018 at 3:46 AM, Chao Fan <fanc.fnst@cn.fujitsu.com> wrote:
> There is a bug that kaslr may randomly chooses some positions
> which are located in movable memory regions. This will break memory
> hotplug feature and make the movable memory chosen by KASLR can't be
> removed. So dig SRAT table from ACPI tables to get memory information.
>
> Imitate the ACPI code of parsing ACPI tables to dig and read ACPI
> tables. Since some operations are not needed here, functions are
> simplified. Functions will be used to dig only SRAT tables to get
> information of memory, so that KASLR can the memory in immovable node.
>
> And also, these functions won't influence the initialization of
> ACPI after start_kernel().
>
> Since use physical address directely, so acpi_os_map_memory()
> and acpi_os_unmap_memory() are not needed.
>
> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
> ---
> arch/x86/boot/compressed/Makefile | 4 +
> arch/x86/boot/compressed/acpitb.c | 401 ++++++++++++++++++++++++++++++

Does this logic live anywhere else in the kernel already? (i.e. could
other code be reused?)

-Kees

--
Kees Cook
Pixel Security