Re: [PATCH v3 2/3] ACPI / ARM64: add BAD_MADT_GICC_ENTRY() macro

Catalin Marinas
2015-07-06T10:34:03Z

On Sat, Jul 04, 2015 at 01:54:15AM +0200, Rafael J. Wysocki wrote:
> On Friday, July 03, 2015 01:51:36 PM Al Stone wrote:
> > Perhaps the sanity checking for the MADT subtables needs to be revisited
> > and a more general solution provided -- this is not the only MADT subtable
> > with this problem and it may occur again.
> >
> > Even the versions above are not technically compliant with the spec. If
> > we implement what the spec currently says, it might look something like
> > this:
> >
> > #define ACPI_MADT_GICC_LENGTH ({ \
> > u8 length; \
> > switch (ACPI_FADT_SPEC_VERSION) { \
> > case ACPI_FADT_SPEC_VERSION_5_0: \
> > length = 40; \
> > break; \
> > case ACPI_FADT_SPEC_VERSION_5_1: \
> > length = 76; \
> > break; \
> > default: /* use 6.0 size */ \
> > length = 80; \
> > } \
> > length; \
> > })
> >
> > So it's just messy and there will be a need for change. Let me think about
> > making this a function instead of a macro; it may make sense to really fix
> > BAD_MADT_ENTRY in general instead of just dealing with the GICC subtable,
> > but it could also be overkill.
>
> So here's my suggestion.
>
> First, make ARM64 boot with 4.2+ in the simplest way possible.
>
> Second, set out to fix BAD_MADT_ENTRY() etc. Start with fixing ACPICA to
> distinguish between the different formats depending on the spec version and
> follow up from there.

That's fine by me (as long as there is a plan to fix it properly,
ideally in 4.3).

--
Catalin