diff options
Diffstat (limited to 'mm/page_table_check.c')
| -rw-r--r-- | mm/page_table_check.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/mm/page_table_check.c b/mm/page_table_check.c index af69c3c8f7c2..509c6ef8de40 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 @@ -71,6 +73,9 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) page = pfn_to_page(pfn); page_ext = page_ext_get(page); + if (!page_ext) + return; + BUG_ON(PageSlab(page)); anon = PageAnon(page); @@ -108,6 +113,9 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, page = pfn_to_page(pfn); page_ext = page_ext_get(page); + if (!page_ext) + return; + BUG_ON(PageSlab(page)); anon = PageAnon(page); @@ -138,7 +146,10 @@ void __page_table_check_zero(struct page *page, unsigned int order) BUG_ON(PageSlab(page)); page_ext = page_ext_get(page); - BUG_ON(!page_ext); + + if (!page_ext) + return; + for (i = 0; i < (1ul << order); i++) { struct page_table_check *ptc = get_page_table_check(page_ext); @@ -182,6 +193,22 @@ 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 +217,8 @@ 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 +226,21 @@ 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, |