[PATCH v3] powerpc: mm: support ARCH_MMAP_RND_BITS

[Balbir Singh]

>>
>> 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?

Balbir