Re: [PATCH v4 0/2] Correct for ACPI 5.1->6.0 spec changes in MADT GICC entries

[Catalin Marinas]

On Tue, Jul 07, 2015 at 01:20:51AM +0200, Rafael J. Wysocki wrote:
> On Tue, Jul 7, 2015 at 1:16 AM, Al Stone <al.stone@xxxxxxxxxx> 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 does not appear to have this
> > problem since it still has the 5.1 struct definition.
> >
> > Though there is precedent in ia64 code for ignoring the changes in size,
> > this patch set instead verifies correctness.  The first patch adds the
> > BAD_MADT_GICC_ENTRY() macro to check the GICC subtable only, accounting
> > for the difference in specification versions that are possible.  The
> > second 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.e., the system
> > will boot with either Linux 4.1 or linux-next kernels using the same ACPI
> > 5.1 compatible firmware.
> 
> ACK for the series, but I guess it's better to let it go via ARM64, right?

Fine by me. I'll pick them up for 4.2-rc2.

Thanks.

-- 
Catalin
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