[PATCH] powerpc/85xx: allow CONFIG_PHYS_64BIT to be selectable

[Li Yang-R58472]

> Subject: Re: [PATCH] powerpc/85xx: allow CONFIG_PHYS_64BIT to be
> selectable
> 
> Li Yang-R58472 wrote:
> 
> > The mpc85xx_defconfig does include silicons with e500v1 core which
> > doesn't have the 36-bit support.  Won't enabling 36-bit support by
> > default break the support for them?
> 
> No.  The kernel will detect at runtime that that it's an e500v1 core and
> it won't try to create 36-bit TLBs. (e.g. it won't write to MAS7).

It's a good point.  Why can't we decide to use 32-bit/36-bit TLB at runtime even for e500v2?

> 
> Please remember that the Kconfig for the P1022DS already forced
> PHYS_64BIT for all mpc85xx platforms.  All we're doing is making it
> possible to deselect PHYS_64BIT.

I think it's a side-effect introduced by P1022DS support and need to be fixed.  There was no mentioning of enforcing 36-bit for all mpc85xx platforms.

- Leo