[036/166] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers

Commit Message

Andrew Morton April 7, 2020, 3:05 a.m. UTC

From: Andrea Arcangeli <[e-mail]>
Subject: userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers

Implement helpers methods to invoke userfaultfd wp faults more
selectively: not only when a wp fault triggers on a vma with vma->vm_flags
VM_UFFD_WP set, but only if the _PAGE_UFFD_WP bit is set in the pagetable
too.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Andrea Arcangeli <[e-mail]>
Signed-off-by: Peter Xu <[e-mail]>
Reviewed-by: Jerome Glisse <[e-mail]>
Reviewed-by: Mike Rapoport <[e-mail]>
Cc: Bobby Powers <[e-mail]>
Cc: Brian Geffon <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: Denis Plotnikov <[e-mail]>
Cc: "Dr . David Alan Gilbert" <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: "Kirill A . Shutemov" <[e-mail]>
Cc: Martin Cracauer <[e-mail]>
Cc: Marty McFadden <[e-mail]>
Cc: Maya Gokhale <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Cc: Pavel Emelyanov <[e-mail]>
Cc: Rik van Riel <[e-mail]>
Cc: Shaohua Li <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/userfaultfd_k.h |   27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

Patch

--- a/include/linux/userfaultfd_k.h~userfaultfd-wp-userfaultfd_pte-huge_pmd_wp-helpers
+++ a/include/linux/userfaultfd_k.h
@@ -14,6 +14,8 @@ 
 #include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
 
 #include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <asm-generic/pgtable_uffd.h>
 
 /*
  * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
@@ -57,6 +59,18 @@  static inline bool userfaultfd_wp(struct
 	return vma->vm_flags & VM_UFFD_WP;
 }
 
+static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
+				      pte_t pte)
+{
+	return userfaultfd_wp(vma) && pte_uffd_wp(pte);
+}
+
+static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
+					   pmd_t pmd)
+{
+	return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
+}
+
 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 {
 	return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
@@ -106,6 +120,19 @@  static inline bool userfaultfd_wp(struct
 	return false;
 }
 
+static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
+				      pte_t pte)
+{
+	return false;
+}
+
+static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
+					   pmd_t pmd)
+{
+	return false;
+}
+
+
 static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 {
 	return false;