[PATCH] ARM: formalize an IPI for CPU wake-ups

[Nicolas Pitre]

On Wed, 29 Aug 2012, Stephen Boyd wrote:

> 
> On 8/22/2012 12:05 PM, Stephen Boyd wrote:
> > Ok, I've put it in the patch tracker.
> >
> 
> Russell, what's involved in getting rid of the printk now? Can we just
> shift everything down by 1 and then formalize 0 as the wakeup ipi? Or do
> you want to completely remove that ipi from the stats? It's not clear to
> me what we should do. Something like the following untested patch would
> be a possibility.

Please make this into a proper patch and send it to the patch system 
with...

Reviewed-by: Nicolas Pitre <nico at linaro.org>

I do need this and would prefer to use a version likely to hit mainline 
rather than a local version.  And I don't think we should remove IPI 0 
from the stats.

> ----8<------->8------
> 
> diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h
> index 436e60b..2740c2a2 100644
> --- a/arch/arm/include/asm/hardirq.h
> +++ b/arch/arm/include/asm/hardirq.h
> @@ -5,7 +5,7 @@
>  #include <linux/threads.h>
>  #include <asm/irq.h>
> 
> -#define NR_IPI 5
> +#define NR_IPI 6
> 
>  typedef struct {
>         unsigned int __softirq_pending;
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index ebd8ad2..d98c37e 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -51,7 +51,8 @@
>  struct secondary_data secondary_data;
> 
>  enum ipi_msg_type {
> -       IPI_TIMER = 2,
> +       IPI_WAKEUP,
> +       IPI_TIMER,
>         IPI_RESCHEDULE,
>         IPI_CALL_FUNC,
>         IPI_CALL_FUNC_SINGLE,
> @@ -347,7 +348,8 @@ void arch_send_call_function_single_ipi(int cpu)
>  }
> 
>  static const char *ipi_types[NR_IPI] = {
> -#define S(x,s) [x - IPI_TIMER] = s
> +#define S(x,s) [x] = s
> +       S(IPI_WAKEUP, "CPU wakeup interrupts"),
>         S(IPI_TIMER, "Timer broadcast interrupts"),
>         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
>         S(IPI_CALL_FUNC, "Function call interrupts"),
> @@ -500,10 +502,13 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
>         unsigned int cpu = smp_processor_id();
>         struct pt_regs *old_regs = set_irq_regs(regs);
> 
> -       if (ipinr >= IPI_TIMER && ipinr < IPI_TIMER + NR_IPI)
> -               __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_TIMER]);
> +       if (ipinr < NR_IPI)
> +               __inc_irq_stat(cpu, ipi_irqs[ipinr]);
> 
>         switch (ipinr) {
> +       case IPI_WAKEUP:
> +               break;
> +
>         case IPI_TIMER:
>                 irq_enter();
>                 ipi_timer();
> 
> -- 
> Sent by an employee of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
>