Yuri Tikhonov writes:

 The configuration option we had introduced changes the global PPC PAGE_SIZE 
definition indeed. To let changing the PAGE_SIZE from the configuration menu 
for the 44x processors only the following modification of the 
arch/ppc/Kconfig file might make sense:

 - int "Page size (12=>4KB; 16=>64KB)"
+ int "Page size (12=>4KB; 16=>64KB)" if 44x

 For other than 44x processors the PPC_PAGE_SHIFT value will be unchangeable 
from the configuration menu and set to default  value 12 ( PAGE_SIZE = 4 KB).

Your patch would still let users select a page shift of 13 or 15,
which won't work (and can't be made to work).

Paul.