[PATCH 08/16] ARM: bL_platsmp.c: make sure the GIC interface of a dying CPU is disabled
Will Deacon
will.deacon at arm.com
Mon Jan 14 12:02:10 EST 2013
On Mon, Jan 14, 2013 at 04:54:52PM +0000, Nicolas Pitre wrote:
> On Mon, 14 Jan 2013, Will Deacon wrote:
>
> > On Thu, Jan 10, 2013 at 12:20:43AM +0000, Nicolas Pitre wrote:
> > > Otherwise there might be some interrupts or IPIs becoming pending and the
> > > CPU will not enter low power mode when doing a WFI. The effect of this
> > > is a CPU that loops back into the kernel, go through the first man
> > > election, signals itself as alive, and prevent the cluster from being
> > > shut down.
> > >
> > > This could benefit from a better solution.
> > >
> > > Signed-off-by: Nicolas Pitre <nico at linaro.org>
> > > ---
> > > arch/arm/common/bL_platsmp.c | 1 +
> > > arch/arm/common/gic.c | 6 ++++++
> > > arch/arm/include/asm/hardware/gic.h | 2 ++
> > > 3 files changed, 9 insertions(+)
> > >
> > > diff --git a/arch/arm/common/bL_platsmp.c b/arch/arm/common/bL_platsmp.c
> > > index 0ae44123bf..6a3b251b97 100644
> > > --- a/arch/arm/common/bL_platsmp.c
> > > +++ b/arch/arm/common/bL_platsmp.c
> > > @@ -68,6 +68,7 @@ static void __ref bL_cpu_die(unsigned int cpu)
> > > pcpu = mpidr & 0xff;
> > > pcluster = (mpidr >> 8) & 0xff;
> > > bL_set_entry_vector(pcpu, pcluster, NULL);
> > > + gic_cpu_if_down();
> >
> > I'm starting to sound like a stuck record (and not a very tuneful one at
> > that) but... I think you need a barrier here.
>
> And I'm getting puzzled at the repetition. ;-)
Sorry! This case is more interesting though, because you also want to order
the cpu_if_down GIC write so that it completes before we do the power_off.
Will
More information about the linux-arm-kernel
mailing list