nonlinear vma problem in uml

nonlinear vma problem in uml

[Miklos Szeredi]

_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 <mszeredi@suse.cz>
---

Index: linux/include/asm-um/pgtable-2level.h
===================================================================
--- linux.orig/include/asm-um/pgtable-2level.h	2007-03-02 23:03:15.000000000 +0100
+++ linux/include/asm-um/pgtable-2level.h	2007-03-02 23:03:26.000000000 +0100
@@ -45,12 +45,12 @@ static inline void pgd_mkuptodate(pgd_t 
 	((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

Re: nonlinear vma problem in uml

[Jeff Dike]

On Sat, Mar 03, 2007 at 12:06:20AM +0100, Miklos Szeredi wrote:
> _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.

Thanks, I'll send this in.

				Jeff

-- 
Work email - jdike at linux dot intel dot com