On Thu, 29 Nov 2012, Russell King - ARM Linux wrote:

On Thu, Nov 29, 2012 at 10:45:50AM -0500, Nicolas Pitre wrote:

quoted

On Thu, 29 Nov 2012, Rob Herring wrote:

quoted

Signed-off-by: Rob Herring <redacted>
Acked-by: Will Deacon <redacted>

With the above, and moving the call to cpu_init() after the call to 
cpu_switch_mm(mm->pgd, mm) to fix Will's concerns (personally I'd put it 
right after local_flush_tlb_all())... 

You're confused.  We were suggesting before the printk().

The reasoning is: printk() is not guaranteed not to access per-cpu
variables, so it needs to be before the first printk.  It can't be
before cpu_switch_mm(), and putting it before the TLB flush does
_not_ guarantee that TLB/MMU isn't going to still be seeing the
strongly-ordered attribute - so it _must_ be after the TLB flush.

But isn't that what I wrote above?  I said "personally I'd put it right 
after local_flush_tlb_all()".

As for the setup of the active MM, that's something that I still
think should come as early as possible (even before the per-cpu
stuff) because that is getting everything properly initialized and
setup for this new thread; there's a risk that a fault occuring
before that point may cause issues, specially if active_mm were NULL.

Good point.

So, between cpumask_set_cpu() and printk() please.

Agreed.


Nicolas