From 138c9021ca68d6f8a6fac3418995fee102a3cc22 Mon Sep 17 00:00:00 2001
From: Nick Piggin <npiggin@suse.de>
Date: Tue, 8 Jul 2008 11:31:06 +0200
Subject: [PATCH] [S390] protect _PAGE_SPECIAL bit against mprotect
Stop mprotect's pte_modify from wiping out the s390 pte_special bit, which
caused oops thereafter when vm_normal_page thought X's abnormal was normal.
Debugged-by: Ryan Hope <rmh3093@gmail.com>
Debugged-by: Zan Lynx <zlynx@acm.org>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
include/asm-s390/pgtable.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index c7f4f8e3e29..bd0ea191dfa 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -223,6 +223,9 @@ extern char empty_zero_page[PAGE_SIZE];
#define _PAGE_SPECIAL 0x004 /* SW associated with special page */
#define __HAVE_ARCH_PTE_SPECIAL
+/* Set of bits not changed in pte_modify */
+#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_SPECIAL)
+
/* Six different types of pages. */
#define _PAGE_TYPE_EMPTY 0x400
#define _PAGE_TYPE_NONE 0x401
@@ -681,7 +684,7 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *pt
*/
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
- pte_val(pte) &= PAGE_MASK;
+ pte_val(pte) &= _PAGE_CHG_MASK;
pte_val(pte) |= pgprot_val(newprot);
return pte;
}
--
2.41.3