[RFC PATCH v2 3/4] powerpc: Don't bolt the hpte in kernel_map_linear_page()

[Li Zhong]

On Mon, 2013-04-15 at 13:27 +0200, Benjamin Herrenschmidt wrote:
> On Mon, 2013-04-15 at 16:15 +0800, Li Zhong wrote:
> 
> > So the code is implemented in ppc_md.hpte_remove(), may be called by
> > __hash_huge_page(), and asm code htab_call_hpte_remove?
> > 
> > > This is why the linear mapping (and the vmemmap) must be bolted.
> > 
> > If not, it would result the infinite recursion like above?
> 
> Potentially, we don't expect to fault linear mapping or vmemmap entries
> on demand. We aren't equipped to do it and we occasionally have code
> path that access the linear mapping and cannot afford to have SRR0 and
> SRR1 clobbered by a page fault.

Thank you for the education :)

Thanks, Zhong

> 
> Cheers,
> Ben.
> 
>