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

[Catalin Marinas <catalin.marinas@arm.com>]

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