Re: [Xen-devel] [PATCH V2] xen/arm: Missing +1 when then number of interrupt lines for the GIC is computed

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-04-29 at 14:25 +0100, Julien Grall wrote:
> In the GIC manual, the number of interrupt lines is computed with the 
> following
> formula: 32(N + 1) where N is the value retrieved from GICD_TYPER.
> 
> Without the +1 Xen doesn't initialize the last 32 interrupts and can get
> garbagge on these registers.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Acked + applied.

I rewrote the first line to fit in 80 characters:
"xen/arm: correct the computation of the number of interrupt lines for the GIC"


> ---
>  Modifications since v1:
>    - Precise the impact in the commit message
>    - Add description for the variable "lines"
> 
>  xen/arch/arm/gic.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 377b676..0fd8635 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -44,7 +44,7 @@ static struct {
>      paddr_t cbase;       /* Address of CPU interface registers */
>      paddr_t hbase;       /* Address of virtual interface registers */
>      paddr_t vbase;       /* Address of virtual cpu interface registers */
> -    unsigned int lines;
> +    unsigned int lines;  /* Number of interrupts (SPIs + PPIs + SGIs) */
>      unsigned int cpus;
>      spinlock_t lock;
>  } gic;
> @@ -214,7 +214,7 @@ static int gic_route_irq(unsigned int irq, bool_t level,
>  
>      ASSERT(!(cpu_mask & ~0xff));  /* Targets bitmap only supports 8 CPUs */
>      ASSERT(priority <= 0xff);     /* Only 8 bits of priority */
> -    ASSERT(irq < gic.lines + 32); /* Can't route interrupts that don't exist 
> */
> +    ASSERT(irq < gic.lines);      /* Can't route interrupts that don't exist 
> */
>  
>      spin_lock_irqsave(&desc->lock, flags);
>      spin_lock(&gic.lock);
> @@ -251,7 +251,7 @@ static void __init gic_dist_init(void)
>      GICD[GICD_CTLR] = 0;
>  
>      type = GICD[GICD_TYPER];
> -    gic.lines = 32 * (type & GICD_TYPE_LINES);
> +    gic.lines = 32 * ((type & GICD_TYPE_LINES) + 1);
>      gic.cpus = 1 + ((type & GICD_TYPE_CPUS) >> 5);
>      printk("GIC: %d lines, %d cpu%s%s (IID %8.8x).\n",
>             gic.lines, gic.cpus, (gic.cpus == 1) ? "" : "s",



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