Re: [PATCH v2] xen/arm: disable cpuidle and cpufreq when linux isrunning as dom0

From: Konrad Rzeszutek Wilk
Date: Fri Jul 19 2013 - 09:51:34 EST


On Fri, Jul 19, 2013 at 12:27:00PM +0100, Julien Grall wrote:
> When linux is running as dom0, Xen doesn't show the physical cpu but a
> virtual CPU.
> On some ARM SOC (for instance the exynos 5250), linux registers callbacks
> for cpuidle and cpufreq. When these callbacks are called, they will modify
> directly the physical cpu not the virtual one. It can impact the whole board
> instead of only dom0.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>
> ---
> Changes in v2:
> - Disable cpufreq
> ---
> arch/arm/xen/enlighten.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 49839d8..af82792 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -24,6 +24,8 @@
> #include <linux/of.h>
> #include <linux/of_irq.h>
> #include <linux/of_address.h>
> +#include <linux/cpuidle.h>
> +#include <linux/cpufreq.h>
>
> #include <linux/mm.h>
>
> @@ -292,6 +294,12 @@ static int __init xen_pm_init(void)
> {
> pm_power_off = xen_power_off;
> arm_pm_restart = xen_restart;
> + /*
> + * Making sure board specific code will not set up ops for
> + * cpu idle and cpu freq.
> + */
> + disable_cpuidle();
> + disable_cpufreq();
>
> return 0;
> }
> --
> 1.7.10.4
>
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