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

[Tabi Timur-B04825 <B04825@freescale.com>]

Li Yang-R58472 wrote:

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

That's not what PHYS_64BIT does.  PHYS_64BIT determines whether=20
phys_addr_t is a u64 or a u32.  This is something that must be determined=20
at compilation time.

>> 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 f=
ixed.

Exactly.  That's what these patches do.  And these patches have been=20
applied to the SDK.  I'm just waiting for Kumar to apply them to his=20
repository.

> There was no mentioning of enforcing 36-bit for all mpc85xx platforms.

It's not enforcing, it's just the default.  If you build with=20
mpc85xx_smp_defconfig, then you'll get a 36-bit kernel.  But now you can=20
also use menuconfig to turn off PHYS_64BIT.  Before these fixes, that was=20
not possible.

--=20
Timur Tabi
Linux kernel developer at Freescale=