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Diffstat (limited to 'mm/page_table_check.c')
-rw-r--r--mm/page_table_check.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index af69c3c8f7c2..4169576bed72 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -7,6 +7,8 @@
#include <linux/kstrtox.h>
#include <linux/mm.h>
#include <linux/page_table_check.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
#undef pr_fmt
#define pr_fmt(fmt) "page_table_check: " fmt
@@ -182,6 +184,22 @@ void __page_table_check_pud_clear(struct mm_struct *mm, pud_t pud)
}
EXPORT_SYMBOL(__page_table_check_pud_clear);
+/* Whether the swap entry cached writable information */
+static inline bool swap_cached_writable(swp_entry_t entry)
+{
+ return is_writable_device_exclusive_entry(entry) ||
+ is_writable_device_private_entry(entry) ||
+ is_writable_migration_entry(entry);
+}
+
+static inline void page_table_check_pte_flags(pte_t pte)
+{
+ if (pte_present(pte) && pte_uffd_wp(pte))
+ WARN_ON_ONCE(pte_write(pte));
+ else if (is_swap_pte(pte) && pte_swp_uffd_wp(pte))
+ WARN_ON_ONCE(swap_cached_writable(pte_to_swp_entry(pte)));
+}
+
void __page_table_check_ptes_set(struct mm_struct *mm, pte_t *ptep, pte_t pte,
unsigned int nr)
{
@@ -190,6 +208,8 @@ void __page_table_check_ptes_set(struct mm_struct *mm, pte_t *ptep, pte_t pte,
if (&init_mm == mm)
return;
+ page_table_check_pte_flags(pte);
+
for (i = 0; i < nr; i++)
__page_table_check_pte_clear(mm, ptep_get(ptep + i));
if (pte_user_accessible_page(pte))
@@ -197,11 +217,21 @@ void __page_table_check_ptes_set(struct mm_struct *mm, pte_t *ptep, pte_t pte,
}
EXPORT_SYMBOL(__page_table_check_ptes_set);
+static inline void page_table_check_pmd_flags(pmd_t pmd)
+{
+ if (pmd_present(pmd) && pmd_uffd_wp(pmd))
+ WARN_ON_ONCE(pmd_write(pmd));
+ else if (is_swap_pmd(pmd) && pmd_swp_uffd_wp(pmd))
+ WARN_ON_ONCE(swap_cached_writable(pmd_to_swp_entry(pmd)));
+}
+
void __page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd)
{
if (&init_mm == mm)
return;
+ page_table_check_pmd_flags(pmd);
+
__page_table_check_pmd_clear(mm, *pmdp);
if (pmd_user_accessible_page(pmd)) {
page_table_check_set(pmd_pfn(pmd), PMD_SIZE >> PAGE_SHIFT,