Merge tag 'cgroup-for-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

[platform/kernel/linux-starfive.git] / mm / mprotect.c

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 36351a0..92d3d3c 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -223,8 +223,6 @@ static long change_pte_range(struct mmu_gather *tlb,
                                newpte = swp_entry_to_pte(entry);
                                if (pte_swp_soft_dirty(oldpte))
                                        newpte = pte_swp_mksoft_dirty(newpte);
-                               if (pte_swp_uffd_wp(oldpte))
-                                       newpte = pte_swp_mkuffd_wp(newpte);
                        } else if (is_writable_device_private_entry(entry)) {
                                /*
                                 * We do not preserve soft-dirtiness. See
@@ -276,7 +274,15 @@ static long change_pte_range(struct mmu_gather *tlb,
                } else {
                        /* It must be an none page, or what else?.. */
                        WARN_ON_ONCE(!pte_none(oldpte));
-                       if (unlikely(uffd_wp && !vma_is_anonymous(vma))) {
+
+                       /*
+                        * Nobody plays with any none ptes besides
+                        * userfaultfd when applying the protections.
+                        */
+                       if (likely(!uffd_wp))
+                               continue;
+
+                       if (userfaultfd_wp_use_markers(vma)) {
                                /*
                                 * For file-backed mem, we need to be able to
                                 * wr-protect a none pte, because even if the
@@ -320,23 +326,46 @@ static inline int pmd_none_or_clear_bad_unless_trans_huge(pmd_t *pmd)
        return 0;
 }
 
-/* Return true if we're uffd wr-protecting file-backed memory, or false */
+/*
+ * Return true if we want to split THPs into PTE mappings in change
+ * protection procedure, false otherwise.
+ */
 static inline bool
-uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags)
+pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
 {
+       /*
+        * pte markers only resides in pte level, if we need pte markers,
+        * we need to split.  We cannot wr-protect shmem thp because file
+        * thp is handled differently when split by erasing the pmd so far.
+        */
        return (cp_flags & MM_CP_UFFD_WP) && !vma_is_anonymous(vma);
 }
 
 /*
- * If wr-protecting the range for file-backed, populate pgtable for the case
- * when pgtable is empty but page cache exists.  When {pte|pmd|...}_alloc()
- * failed we treat it the same way as pgtable allocation failures during
- * page faults by kicking OOM and returning error.
+ * Return true if we want to populate pgtables in change protection
+ * procedure, false otherwise
+ */
+static inline bool
+pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
+{
+       /* If not within ioctl(UFFDIO_WRITEPROTECT), then don't bother */
+       if (!(cp_flags & MM_CP_UFFD_WP))
+               return false;
+
+       /* Populate if the userfaultfd mode requires pte markers */
+       return userfaultfd_wp_use_markers(vma);
+}
+
+/*
+ * Populate the pgtable underneath for whatever reason if requested.
+ * When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
+ * allocation failures during page faults by kicking OOM and returning
+ * error.
  */
 #define  change_pmd_prepare(vma, pmd, cp_flags)                                \
        ({                                                              \
                long err = 0;                                           \
-               if (unlikely(uffd_wp_protect_file(vma, cp_flags))) {    \
+               if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
                        if (pte_alloc(vma->vm_mm, pmd))                 \
                                err = -ENOMEM;                          \
                }                                                       \
@@ -351,7 +380,7 @@ uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags)
 #define  change_prepare(vma, high, low, addr, cp_flags)                        \
          ({                                                            \
                long err = 0;                                           \
-               if (unlikely(uffd_wp_protect_file(vma, cp_flags))) {    \
+               if (unlikely(pgtable_populate_needed(vma, cp_flags))) { \
                        low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
                        if (p == NULL)                                  \
                                err = -ENOMEM;                          \
@@ -404,7 +433,7 @@ static inline long change_pmd_range(struct mmu_gather *tlb,
 
                if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
                        if ((next - addr != HPAGE_PMD_SIZE) ||
-                           uffd_wp_protect_file(vma, cp_flags)) {
+                           pgtable_split_needed(vma, cp_flags)) {
                                __split_huge_pmd(vma, pmd, addr, false, NULL);
                                /*
                                 * For file-backed, the pmd could have been