ACPI: regression: Failed to initialize GIC IRQ controller

[Lorenzo Pieralisi]

On Fri, Jul 10, 2015 at 03:45:32PM +0100, Moore, Robert wrote:
> It's nice that someone took a sizeof() on the struct -- so, one would hope that no code actually depended on a particular value, no?

Unfortunately that sizeof has been there forever (x86/ia64),
ia64 code ran into a similar issue, so the check was removed
to cope with lsapic MADT updates, see:

arch/ia64/kernel/acpi.c line 204

/*Skip BAD_MADT_ENTRY check, as lsapic size could vary */

Is checking the subtable length field against a static value
really worthwhile/suitable ?

Thanks,
Lorenzo

> > -----Original Message-----
> > From: Ming Lei [mailto:ming.lei at canonical.com]
> > Sent: Friday, July 10, 2015 7:43 AM
> > To: Moore, Robert
> > Cc: Zheng, Lv; Wysocki, Rafael J; Linux Kernel Mailing List; linux-arm-
> > kernel; Thomas Gleixner; Jason Cooper; Hanjun Guo
> > Subject: Re: ACPI: regression: Failed to initialize GIC IRQ controller
> > 
> > On Fri, Jul 10, 2015 at 10:28 PM, Moore, Robert <robert.moore at intel.com>
> > wrote:
> > >
> > >
> > >> -----Original Message-----
> > >> From: Ming Lei [mailto:ming.lei at canonical.com]
> > >> Sent: Friday, July 10, 2015 12:46 AM
> > >> To: Moore, Robert; Zheng, Lv; Wysocki, Rafael J
> > >> Cc: Linux Kernel Mailing List; linux-arm-kernel; Thomas Gleixner;
> > >> Jason Cooper; Hanjun Guo
> > >> Subject: ACPI: regression: Failed to initialize GIC IRQ controller
> > >>
> > >> Hi,
> > >>
> > >> Commit 0cff8dc0099f6d4f(ACPICA: ACPI 6.0: Add changes for MADT
> > >> table.) causes the following failure on APM mustang board(arm64) when
> > >> booting via UEFI and ACPI:
> > >
> > >
> > > I would be interested to know just what exactly about this change broke
> > things.
> > 
> > sizeof(struct acpi_madt_generic_interrupt)
> N???????????????r??????y?????????b???X????????v???^???)??{.n???+????????????{????????????zX??????????????}???????????z???&j:+v?????????????????????zZ+??????+zf?????????h?????????~????????????i?????????z??????w??????????????????????&???)??f??????^j??y???m??????@A???a?????????0??????h??????i