Re: [PATCH V2 1/2] xen/arm: gic_disable_cpu must be called with interrupts disabled

[Julien Grall <julien.grall@citrix.com>]

On 05/01/2013 12:55 PM, Ian Campbell wrote:

> On Tue, 2013-04-16 at 14:38 +0100, Julien Grall wrote:
>> gic_disable_cpu is only called with interrupt disabled.
>> Use spin_lock instead of spin_lock_irq and check the function is
>> called with interrupts disabled.
> 
> Is this patch still relevant after this change which is now in master?


Yes. gic_disable is only called by __cpu_disable, and the irq is disabled.

local_irq_disable();
gic_disable_cpu();

> 
> commit b4aae03ce525e8e2364814d0fed8f982aefc4958
> Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Date:   Mon Apr 29 18:04:25 2013 +0100
> 
>     xen/arm: do not call __cpu_disable on machine_halt
>     
>     __cpu_disable shouldn't be called on machine_halt, in fact it cannot
>     succeed: cpu_disable_scheduler won't be able to migrate away vcpus to
>     others pcpus.
>     
>     Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
>     Acked-by: Ian Campbell <ian.campbell@citrix.com>
> 
>>
>> Signed-off-by: Julien Grall <julien.grall@citrix.com>
>> ---
>>  xen/arch/arm/gic.c |    6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
>> index aa179a9..0ef994e 100644
>> --- a/xen/arch/arm/gic.c
>> +++ b/xen/arch/arm/gic.c
>> @@ -419,10 +419,12 @@ void __cpuinit gic_init_secondary_cpu(void)
>>  /* Shut down the per-CPU GIC interface */
>>  void gic_disable_cpu(void)
>>  {
>> -    spin_lock_irq(&gic.lock);
>> +    ASSERT(!local_irq_is_enabled());
>> +
>> +    spin_lock(&gic.lock);
>>      gic_cpu_disable();
>>      gic_hyp_disable();
>> -    spin_unlock_irq(&gic.lock);
>> +    spin_unlock(&gic.lock);
>>  }
>>  
>>  void gic_route_ppis(void)
> 
>