[PATCH 1/2] ARM: tlb: don't perform inner-shareable invalidation for local TLB ops

[Will Deacon]

Hi Russell,

On Fri, May 17, 2013 at 06:04:11PM +0100, Russell King - ARM Linux wrote:
> On Fri, May 17, 2013 at 05:54:37PM +0100, Will Deacon wrote:
> >  	if (possible_tlb_flags & (TLB_V4_U_FULL|TLB_V4_D_FULL|TLB_V4_I_FULL)) {
> > -		if (cpumask_test_cpu(get_cpu(), mm_cpumask(mm))) {
> > +		if (cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm))) {
> >  			tlb_op(TLB_V4_U_FULL, "c8, c7, 0", zero);
> >  			tlb_op(TLB_V4_D_FULL, "c8, c6, 0", zero);
> >  			tlb_op(TLB_V4_I_FULL, "c8, c5, 0", zero);
> >  		}
> > -		put_cpu();
> 
> NAK.  You may wish to read daaeb6c93829806221b2ac533330c64f338ebb89
> which changed this from smp_processor_id() _to_ using get_cpu()/put_cpu().

With these changes, it would be a bug to call a local_* operation from
preemptible context, so the issue described in the commit above will never
trigger from properly written code. Since the flush_* operations are moved
to non-local variants, that shouldn't affect any existing users.

Will