[PATCH] uml: fix pte bit collision

_PAGE_PROTNONE conflicts with the lowest bit of pgoff.  This causes all sorts
of weirdness when nonlinear mappings are used.

Took me a good half day to track this down.

Signed-off-by: Miklos Szeredi <[email protected]>
Signed-off-by: Jeff Dike <[email protected]>
Acked-by: Paolo 'Blaisorblade' Giarrusso <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/asm-um/pgtable-2level.h b/include/asm-um/pgtable-2level.h
index 6050e0eb257e0f2b81601b29fd4d049f7acd07e0..172a75fde51285c49803a3843dbe74d743c62a03 100644 (file)
--- a/include/asm-um/pgtable-2level.h
+++ b/include/asm-um/pgtable-2level.h
@@ -45,12 +45,12 @@ static inline void pgd_mkuptodate(pgd_t pgd)        { }
        ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 
 /*
- * Bits 0 through 3 are taken
+ * Bits 0 through 4 are taken
  */
-#define PTE_FILE_MAX_BITS      28
+#define PTE_FILE_MAX_BITS      27
 
-#define pte_to_pgoff(pte) (pte_val(pte) >> 4)
+#define pte_to_pgoff(pte) (pte_val(pte) >> 5)
 
-#define pgoff_to_pte(off) ((pte_t) { ((off) << 4) + _PAGE_FILE })
+#define pgoff_to_pte(off) ((pte_t) { ((off) << 5) + _PAGE_FILE })
 
 #endif