On 05/09/2013 02:35 AM, James Bottomley wrote:
> On Wed, 2013-05-08 at 22:42 +0200, Helge Deller wrote:
>> We need to enable local irqs to avoid this runtime warning.
>>
>> Signed-off-by: Helge Deller <deller@xxxxxx>
>>
>> diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
>> index 55f92b6..2840d43 100644
>> --- a/arch/parisc/kernel/process.c
>> +++ b/arch/parisc/kernel/process.c
>> @@ -286,3 +286,8 @@ void *dereference_function_descriptor(void *ptr)
>> return ptr;
>> }
>> #endif
>> +
>> +void arch_cpu_idle(void)
>> +{
>> + local_irq_enable();
>
> This is definitely wrong. we'd need at least a cpu_relax() in there.
> Without that the cpu will bounce around in the idle loop. I'd advise
> that we simply keep the default cpu_idle_poll().
>
> However, this looks like a kernel bug to me in cpu_idle_loop()? not
> something we should be working around in the arch code.
>
> Thomas, what's going on here? It looks like you can never avoid the
> WARN_ON_ONCE if you don't provide any arch specific idle functions. If
> you wish to allow this case then the correct patch (keeping the WARN_ON)
> would appear to be this one.
>
> James
>
> ----
> diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c
> index 8b86c0c..829e41f 100644
> --- a/kernel/cpu/idle.c
> +++ b/kernel/cpu/idle.c
> @@ -56,6 +56,7 @@ void __weak arch_cpu_idle_dead(void) { }
> void __weak arch_cpu_idle(void)
> {
> cpu_idle_force_poll = 1;
> + local_irq_enable();
> }
>
> /*
>
This patch looks like the correct fix to me.
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Regards,
Srivatsa S. Bhat
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