[PATCH] ppc32: Allow adjust of pfn offset in pte

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@freescale.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h
index 2e88cd9..e135b4a 100644 (file)
--- a/include/asm-ppc/pgtable.h
+++ b/include/asm-ppc/pgtable.h
@@ -431,10 +431,15 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
  * 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)
 
 /*