Re: [PATCH v5 1/1] irqchip/gic-v3: Enable non-coherent redistributors/ITSes ACPI probing

[Marc Zyngier]

On 2024-06-05 08:14, Lorenzo Pieralisi wrote:
> On Mon, Apr 22, 2024 at 10:42:19AM +0200, Lorenzo Pieralisi wrote:
> > On Tue, Jan 23, 2024 at 12:03:32PM +0100, Lorenzo Pieralisi wrote:
> > > The GIC architecture specification defines a set of registers for
> > > redistributors and ITSes that control the sharebility and cacheability
> > > attributes of redistributors/ITSes initiator ports on the interconnect
> > > (GICR_[V]PROPBASER, GICR_[V]PENDBASER, GITS_BASER<n>).
> > >
> > > Architecturally the GIC provides a means to drive shareability and
> > > cacheability attributes signals but it is not mandatory for designs to
> > > wire up the corresponding interconnect signals that control the
> > > cacheability/shareability of transactions.
> > >
> > > Redistributors and ITSes interconnect ports can be connected to
> > > non-coherent interconnects that are not able to manage the
> > > shareability/cacheability attributes; this implicitly makes the
> > > redistributors and ITSes non-coherent observers.
> > >
> > > To enable non-coherent GIC designs on ACPI based systems, parse the MADT
> > > GICC/GICR/ITS subtables non-coherent flags to determine whether the
> > > respective components are non-coherent observers and force the
> > > shareability attributes to be programmed into the redistributors and
> > > ITSes registers.
> > >
> > > An ACPI global function (acpi_get_madt_revision()) is added to retrieve
> > > the MADT revision, in that it is essential to check the MADT revision
> > > before checking for flags that were added with MADT revision 7 so that
> > > if the kernel is booted with an ACPI MADT table with revision < 7 it
> > > skips parsing the newly added flags (that should be zeroed reserved
> > > values for MADT versions < 7 but they could turn out to be buggy and
> > > should be ignored).
> > >
> > > Signed-off-by: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
> > > Cc: Robin Murphy <robin.murphy@xxxxxxx>
> > > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> > > Cc: Marc Zyngier <maz@xxxxxxxxxx>
> > > ---
> > >  drivers/acpi/processor_core.c    | 15 +++++++++++++++
> > >  drivers/irqchip/irq-gic-v3-its.c |  4 ++++
> > >  drivers/irqchip/irq-gic-v3.c     |  9 +++++++++
> > >  include/linux/acpi.h             |  3 +++
> > >  4 files changed, 31 insertions(+)
> >
> > Hi Marc, Rafael,
> >
> > I would kindly ask you please what to do with this patch, it still
> > applies to v6.9-rc5 - I can resend it if needed, ACPICA changes
> > are already merged as-per the cover letter.
>
> Hi Marc, Rafael,
>
> I would kindly ask please what to do with this patch, rebased to 
> v6.10-rc1,
> I can resend it if that's preferred, please let me know.

Please resend it with my:

Acked-by: Marc Zyngier <maz@xxxxxxxxxx>

and Cc'ing Thomas Gleixner.

Thanks,

        M.
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