[PATCH v3] powerpc: mm: support ARCH_MMAP_RND_BITS

[Bhupesh SHARMA]

On Thu, Apr 13, 2017 at 12:39 PM, Balbir Singh <bsingharora at gmail.com> wrote:
>>>
>>> Yes. It was derived from TASK_SIZE :
>>>
>>> http://lxr.free-electrons.com/source/arch/powerpc/include/asm/processor.h#L105
>>>
>>
>> That is getting update to 128TB by default and conditionally to 512TB
>>
>
> Since this is compile time, we should probably keep the scope to 128TB
> for now and see if we want to change things at run time later, since
> the expansion is based on a hint. Suggestions?
>

I think this makes sense. If the conditional expansion to 512TB is
protected by a kconfig symbol, we can use the same to have separate
ranges for 128TB and 512TB using the kconfig symbol as the
differentiating factor.

Also please let me know which branch/tree to use where we are done
with the change making the default to 128TB. My v2 was based on
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
(mater branch), where the TASK_SIZE is set to 46-bits inside
'arch/powerpc/include/asm/processor.h'.

So that I can spin the v3 accordingly.

Thanks,
Bhupesh