[RFC PATCH 05/17] ARM: kernel: save/restore kernel IF

Frank Hofmann frank.hofmann at tomtom.com
Mon Jul 11 12:57:29 EDT 2011

On Mon, 11 Jul 2011, Lorenzo Pieralisi wrote:

[ ... ]
>>> The array of pointers is there to save pgdir on idle entry, one per-cpu.
>> If you're going through cpu_{do_}suspend/resume, the TTBRs are
>> saved/restored anyway, what do you need to keep the virtual addresses
>> around for ?
> Because I switch mm before calling suspend, which is called
> with a cloned pgdir. I am not sure I can avoid that.

On resume, you'll be restoring the same thread as was previously running, 
right ? If so, all you do there is copying current->active_mm->pgd to some 
other place ?

Also, if you'd be using cpu_suspend(), would there still be a need for 
cpu_switch_mm() before ? It'd rather be a case of possibly calling that 
before the MMU-off sequence / cpu_resume() ?

Or is it that you use the new pgdir to make a memory region uncacheable ?


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