Subject: + mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte.patch added to -mm tree
To: gorcunov@xxxxxxxxx,gorcunov@xxxxxxxxxx,jbeulich@xxxxxxxx,xemul@xxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 22 Aug 2013 13:11:09 -0700
The patch titled
Subject: mm: make sure _PAGE_SWP_SOFT_DIRTY bit is not set on present pte
has been added to the -mm tree. Its filename is
mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte.patch
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------------------------------------------------------
From: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 34 +++++++++++++------------
arch/x86/include/asm/pgtable_types.h | 3 ++
2 files changed, 22 insertions(+), 15 deletions(-)
diff -puN arch/x86/include/asm/pgtable.h~mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte arch/x86/include/asm/pgtable.h
--- a/arch/x86/include/asm/pgtable.h~mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte
+++ a/arch/x86/include/asm/pgtable.h
@@ -314,21 +314,6 @@ static inline pmd_t pmd_mksoft_dirty(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);
@@ -445,6 +430,7 @@ pte_t *populate_extra_pte(unsigned long
#ifndef __ASSEMBLY__
#include <linux/mm_types.h>
+#include <linux/mmdebug.h>
#include <linux/log2.h>
static inline int pte_none(pte_t pte)
@@ -863,6 +849,24 @@ static inline void update_mmu_cache_pmd(
{
}
+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 -puN arch/x86/include/asm/pgtable_types.h~mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte arch/x86/include/asm/pgtable_types.h
--- a/arch/x86/include/asm/pgtable_types.h~mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte
+++ a/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
_
Patches currently in -mm which might be from gorcunov@xxxxxxxxx are
arch-x86-include-asm-pgtable-2levelh-clean-up-pte_to_pgoff-and-pgoff_to_pte-helpers.patch
mm-track-vma-changes-with-vm_softdirty-bit.patch
mm-track-vma-changes-with-vm_softdirty-bit-fix.patch
mm-make-sure-_page_swp_soft_dirty-bit-is-not-set-on-present-pte.patch
fs-proc-task_mmuc-check-the-return-value-of-mpol_to_str.patch
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