Re: [Xen-devel] [PATCH 3/7] xen/arm: Initialize correctly IRQ routing

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2013-08-30 at 14:30 +0100, Julien Grall wrote:
> When Xen initialize the GIC distributor, we need to route all the IRQs to
> the boot CPU. The CPU ID can differ between Xen and the GIC.
> 
> When ITARGETSR0 is read, each field will return a value that corresponds
> only to the processor reading the register.

This trick is used a few times in this series, is it really the best way
to figure this out?

Not in some ID register or in DT?

>  So Xen can use the PPI 0 to
> initialize correctly the routing.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> ---
>  xen/arch/arm/gic.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 37a73fb..cadc258 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -275,9 +275,10 @@ void gic_route_dt_irq(const struct dt_irq *irq, const 
> cpumask_t *cpu_mask,
>  static void __init gic_dist_init(void)
>  {
>      uint32_t type;
> -    uint32_t cpumask = 1 << smp_processor_id();
> +    uint32_t cpumask;
>      int i;
>  
> +    cpumask = GICD[GICD_ITARGETSR] & 0xff;
>      cpumask |= cpumask << 8;
>      cpumask |= cpumask << 16;
>  



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