Re: linux-next: Tree for Sep 1

From: Bartlomiej Zolnierkiewicz
Date: Wed Sep 03 2014 - 12:10:12 EST



Hi,

On Tuesday, September 02, 2014 10:00:07 AM Christoph Lameter wrote:
> On Tue, 2 Sep 2014, Christoph Lameter wrote:
>
> > Oww.. This is double indirection deal there. A percpu offset pointing to
> > a pointer?
> >
> > Generally the following is true (definition from
> > include/asm-generic/percpu.h that is used for ARM for raw_cpu_read):
> >
> > #define raw_cpu_read_4(pcp) (*raw_cpu_ptr(&(pcp)))
>
> I think what the issue is that we dropped the fetch of the percpu offset
> in the patch. Instead we are using the address of the variable that
> contains the offset. Does this patch fix it?

Yes, it fixes the problem. Thank you.

Tested-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> Subject: irqchip: Properly fetch the per cpu offset
>
> The raw_cpu_read() conversion dropped the fetch of the offset
> from base->percpu_base in gic_get_percpu_base.
>
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
>
> Index: linux/drivers/irqchip/irq-gic.c
> ===================================================================
> --- linux.orig/drivers/irqchip/irq-gic.c
> +++ linux/drivers/irqchip/irq-gic.c
> @@ -102,7 +102,7 @@ static struct gic_chip_data gic_data[MAX
> #ifdef CONFIG_GIC_NON_BANKED
> static void __iomem *gic_get_percpu_base(union gic_base *base)
> {
> - return raw_cpu_read(base->percpu_base);
> + return raw_cpu_read(*base->percpu_base);
> }
>
> static void __iomem *gic_get_common_base(union gic_base *base)

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