Andrew, Allow the pfn to be offset by more than just PAGE_SHIFT in the pte. Today, PAGE_SHIFT tends to allow us to have 12-bits of flags in the pte. In the future if we have a larger pte we can allocate more bits for flags by offsetting the pfn even further.
Signed-off-by: Kumar Gala <kumar.gala at freescale.com> --- diff -Nru a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h --- a/include/asm-ppc/pgtable.h 2005-04-07 14:25:07 -05:00 +++ b/include/asm-ppc/pgtable.h 2005-04-07 14:25:07 -05:00 @@ -431,10 +431,15 @@ * Conversions between PTE values and page frame numbers. */ -#define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT) +/* in some case we want to additionaly adjust where the pfn is in the pte to + * allow room for more flags */ +#define PFN_SHIFT_OFFSET (PAGE_SHIFT) + +#define pte_pfn(x) (pte_val(x) >> PFN_SHIFT_OFFSET) #define pte_page(x) pfn_to_page(pte_pfn(x)) -#define pfn_pte(pfn, prot) __pte(((pte_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)) +#define pfn_pte(pfn, prot) __pte(((pte_basic_t)(pfn) << PFN_SHIFT_OFFSET) |\ + pgprot_val(prot)) #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot) /*
