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authorCyrill Gorcunov <gorcunov@gmail.com>2013-09-11 14:22:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:58:06 -0700
commitfa0f281cf9de8e6877e6536f18a3fc77368df64d (patch)
treef542d0f6b19d56f4bfddca7d971bac6c00fca63b /arch
parent5a53748568f79641eaf40e41081a2f4987f005c2 (diff)
mm: make sure _PAGE_SWP_SOFT_DIRTY bit is not set on present pte
_PAGE_SOFT_DIRTY bit should never be set on present pte so add VM_BUG_ON to catch any potential future abuse. Also add a comment on _PAGE_SWP_SOFT_DIRTY definition explaining scope of its usage. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/pgtable.h34
-rw-r--r--arch/x86/include/asm/pgtable_types.h3
2 files changed, 22 insertions, 15 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 8d16befdec88..3d1999458709 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -315,21 +315,6 @@ static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
return pmd_set_flags(pmd, _PAGE_SOFT_DIRTY);
}
-static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
-{
- return pte_set_flags(pte, _PAGE_SWP_SOFT_DIRTY);
-}
-
-static inline int pte_swp_soft_dirty(pte_t pte)
-{
- return pte_flags(pte) & _PAGE_SWP_SOFT_DIRTY;
-}
-
-static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
-{
- return pte_clear_flags(pte, _PAGE_SWP_SOFT_DIRTY);
-}
-
static inline pte_t pte_file_clear_soft_dirty(pte_t pte)
{
return pte_clear_flags(pte, _PAGE_SOFT_DIRTY);
@@ -446,6 +431,7 @@ pte_t *populate_extra_pte(unsigned long vaddr);
#ifndef __ASSEMBLY__
#include <linux/mm_types.h>
+#include <linux/mmdebug.h>
#include <linux/log2.h>
static inline int pte_none(pte_t pte)
@@ -864,6 +850,24 @@ static inline void update_mmu_cache_pmd(struct vm_area_struct *vma,
{
}
+static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
+{
+ VM_BUG_ON(pte_present(pte));
+ return pte_set_flags(pte, _PAGE_SWP_SOFT_DIRTY);
+}
+
+static inline int pte_swp_soft_dirty(pte_t pte)
+{
+ VM_BUG_ON(pte_present(pte));
+ return pte_flags(pte) & _PAGE_SWP_SOFT_DIRTY;
+}
+
+static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
+{
+ VM_BUG_ON(pte_present(pte));
+ return pte_clear_flags(pte, _PAGE_SWP_SOFT_DIRTY);
+}
+
#include <asm-generic/pgtable.h>
#endif /* __ASSEMBLY__ */
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index f4843e031131..0ecac257fb26 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -75,6 +75,9 @@
* with swap entry format. On x86 bits 6 and 7 are *not* involved
* into swap entry computation, but bit 6 is used for nonlinear
* file mapping, so we borrow bit 7 for soft dirty tracking.
+ *
+ * Please note that this bit must be treated as swap dirty page
+ * mark if and only if the PTE has present bit clear!
*/
#ifdef CONFIG_MEM_SOFT_DIRTY
#define _PAGE_SWP_SOFT_DIRTY _PAGE_PSE