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    SubjectRe: [PATCH v2 0/3] Correct for ACPI 5.1->6.0 spec changes in MADT GICC entries
    On 06/19/2015 06:36 AM, Al Stone wrote:
    > In the ACPI 5.1 version of the spec, the struct for the GICC subtable
    > (struct acpi_madt_generic_interrupt) of the MADT is 76 bytes long; in
    > ACPI 6.0, the struct is 80 bytes long. But, there is only one definition
    > in ACPICA for this struct -- and that is the 6.0 version. Hence, when
    > BAD_MADT_ENTRY() compares the struct size to the length in the GICC
    > subtable, it fails if 5.1 structs are in use, and there are systems in
    > the wild that have them.
    >
    > Note that this was found in linux-next and these patches apply against
    > that tree and the arm64 kernel tree; 4.1-rc8 does not appear to have this
    > problem since it still has the 5.1 struct definition.
    >
    > Even though there is precendent in ia64 code for ignoring the changes in
    > size, this patch set instead tries to verify correctness. The first patch
    > in the set adds macros for easily using the ACPI spec version. The second
    > patch adds the BAD_MADT_GICC_ENTRY() macro that uses the version macros to
    > check the GICC subtable only, accounting for the difference in specification
    > versions that are possible. The final patch replaces BAD_MADT_ENTRY usage
    > with the BAD_MADT_GICC_ENTRY macro in arm64 code, which is currently the
    > only architecture affected. The BAD_MADT_ENTRY() will continue to work as
    > is for all other MADT subtables.
    >
    > I have tested these patches on an APM Mustang with version 1.15 firmware,
    > where the problem was found, and they fix the problem.

    I also tested on QEMU, it fixed the problem when I was using ACPICA 6.0
    updates for MADT table,

    Tested-by: Hanjun Guo <hanjun.guo@linaro.org>

    Thanks
    Hanjun

    >
    > Changes for v2:
    > -- Replace magic constants with proper defines (Lorenzo)
    > -- Minor syntax clean-up noted by checkpatch
    > -- Send out CCs properly this time
    > -- Minor clean-up of the paragraphs in this cover letter
    >
    >
    > Al Stone (3):
    > ACPI : introduce macros for using the ACPI specification version
    > ACPI: add BAD_MADT_GICC_ENTRY() macro
    > ACPI / ARM64 : use the new BAD_MADT_GICC_ENTRY macro
    >
    > arch/arm64/kernel/smp.c | 2 +-
    > drivers/irqchip/irq-gic.c | 2 +-
    > include/linux/acpi.h | 15 +++++++++++++++
    > 3 files changed, 17 insertions(+), 2 deletions(-)
    >
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