1 files changed, 99 insertions, 44 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e4302fcf0227..8285f497178b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1237,6 +1237,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
 		[ilog2(VM_UFFD_MINOR)]	= "ui",
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
+#ifdef CONFIG_USERFAULTFD_RWP
+		[ilog2(VM_UFFD_RWP)]	= "ur",
+#endif
 #ifdef CONFIG_ARCH_HAS_USER_SHADOW_STACK
 		[ilog2(VM_SHADOW_STACK)] = "ss",
 #endif
@@ -2035,14 +2038,14 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 		page = vm_normal_page(vma, addr, pte);
 		if (pte_soft_dirty(pte))
 			flags |= PM_SOFT_DIRTY;
-		if (pte_uffd_wp(pte))
+		if (pte_uffd(pte))
 			flags |= PM_UFFD_WP;
 	} else {
 		softleaf_t entry;
 
 		if (pte_swp_soft_dirty(pte))
 			flags |= PM_SOFT_DIRTY;
-		if (pte_swp_uffd_wp(pte))
+		if (pte_swp_uffd(pte))
 			flags |= PM_UFFD_WP;
 		entry = softleaf_from_pte(pte);
 		if (pm->show_pfn) {
@@ -2108,7 +2111,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
 		flags |= PM_PRESENT;
 		if (pmd_soft_dirty(pmd))
 			flags |= PM_SOFT_DIRTY;
-		if (pmd_uffd_wp(pmd))
+		if (pmd_uffd(pmd))
 			flags |= PM_UFFD_WP;
 		if (pm->show_pfn)
 			frame = pmd_pfn(pmd) + idx;
@@ -2127,7 +2130,7 @@ static int pagemap_pmd_range_thp(pmd_t *pmdp, unsigned long addr,
 		flags |= PM_SWAP;
 		if (pmd_swp_soft_dirty(pmd))
 			flags |= PM_SOFT_DIRTY;
-		if (pmd_swp_uffd_wp(pmd))
+		if (pmd_swp_uffd(pmd))
 			flags |= PM_UFFD_WP;
 		if (softleaf_has_pfn(entry))
 			page = softleaf_to_page(entry);
@@ -2233,14 +2236,14 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 		    !hugetlb_pmd_shared(ptep))
 			flags |= PM_MMAP_EXCLUSIVE;
 
-		if (huge_pte_uffd_wp(pte))
+		if (huge_pte_uffd(pte))
 			flags |= PM_UFFD_WP;
 
 		flags |= PM_PRESENT;
 		if (pm->show_pfn)
 			frame = pte_pfn(pte) +
 				((addr & ~hmask) >> PAGE_SHIFT);
-	} else if (pte_swp_uffd_wp_any(pte)) {
+	} else if (pte_swp_uffd_any(pte)) {
 		flags |= PM_UFFD_WP;
 	}
 
@@ -2281,7 +2284,7 @@ static const struct mm_walk_ops pagemap_ops = {
  * Bits 5-54  swap offset if swapped
  * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
  * Bit  56    page exclusively mapped
- * Bit  57    pte is uffd-wp write-protected
+ * Bit  57    pte is tracked by userfaultfd (uffd-wp or RWP)
  * Bit  58    pte is a guard region
  * Bits 59-60 zero
  * Bit  61    page is file-page or shared-anon
@@ -2416,7 +2419,7 @@ static int pagemap_release(struct inode *inode, struct file *file)
 				 PAGE_IS_FILE |	PAGE_IS_PRESENT |	\
 				 PAGE_IS_SWAPPED | PAGE_IS_PFNZERO |	\
 				 PAGE_IS_HUGE | PAGE_IS_SOFT_DIRTY |	\
-				 PAGE_IS_GUARD)
+				 PAGE_IS_GUARD | PAGE_IS_ACCESSED)
 #define PM_SCAN_FLAGS		(PM_SCAN_WP_MATCHING | PM_SCAN_CHECK_WPASYNC)
 
 struct pagemap_scan_private {
@@ -2435,15 +2438,17 @@ static unsigned long pagemap_page_category(struct pagemap_scan_private *p,
 
 	if (pte_none(pte)) {
 		/*
-		 * An unpopulated pte carries no uffd-wp marker, i.e. it is not
-		 * write-protected, the same condition under which the present
-		 * and swap cases below report PAGE_IS_WRITTEN. Report it here
-		 * too so this generic path agrees with the PAGE_IS_WRITTEN fast
-		 * path in pagemap_scan_pmd_entry(), which reports pte_none as
-		 * written and, under PM_SCAN_WP_MATCHING, arms a marker. The
-		 * fast path applies no VMA test, so neither does this.
+		 * An unpopulated pte carries no uffd bit, i.e. it is not
+		 * write-protected. The PAGE_IS_WRITTEN fast path in
+		 * pagemap_scan_pmd_entry() is now gated on a VM_UFFD_WP VMA;
+		 * gate the pte_none report here the same way so the two paths
+		 * still agree. RWP has no such fast path and an unpopulated
+		 * page is not part of the RWP working set, so it is reported as
+		 * neither.
 		 */
-		return PAGE_IS_WRITTEN;
+		if (userfaultfd_wp(vma))
+			return PAGE_IS_WRITTEN;
+		return 0;
 	}
 
 	if (pte_present(pte)) {
@@ -2451,8 +2456,12 @@ static unsigned long pagemap_page_category(struct pagemap_scan_private *p,
 
 		categories = PAGE_IS_PRESENT;
 
-		if (!pte_uffd_wp(pte))
-			categories |= PAGE_IS_WRITTEN;
+		if (!pte_uffd(pte)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 
 		if (p->masks_of_interest & PAGE_IS_FILE) {
 			page = vm_normal_page(vma, addr, pte);
@@ -2469,8 +2478,12 @@ static unsigned long pagemap_page_category(struct pagemap_scan_private *p,
 
 		categories = PAGE_IS_SWAPPED;
 
-		if (!pte_swp_uffd_wp_any(pte))
-			categories |= PAGE_IS_WRITTEN;
+		if (!pte_swp_uffd_any(pte)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 
 		entry = softleaf_from_pte(pte);
 		if (softleaf_is_guard_marker(entry))
@@ -2494,13 +2507,13 @@ static void make_uffd_wp_pte(struct vm_area_struct *vma,
 		pte_t old_pte;
 
 		old_pte = ptep_modify_prot_start(vma, addr, pte);
-		ptent = pte_mkuffd_wp(old_pte);
+		ptent = pte_mkuffd(old_pte);
 		ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
 	} else if (pte_none(ptent)) {
 		set_pte_at(vma->vm_mm, addr, pte,
 			   make_pte_marker(PTE_MARKER_UFFD_WP));
 	} else {
-		ptent = pte_swp_mkuffd_wp(ptent);
+		ptent = pte_swp_mkuffd(ptent);
 		set_pte_at(vma->vm_mm, addr, pte, ptent);
 	}
 }
@@ -2519,8 +2532,12 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
 		struct page *page;
 
 		categories |= PAGE_IS_PRESENT;
-		if (!pmd_uffd_wp(pmd))
-			categories |= PAGE_IS_WRITTEN;
+		if (!pmd_uffd(pmd)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 
 		if (p->masks_of_interest & PAGE_IS_FILE) {
 			page = vm_normal_page_pmd(vma, addr, pmd);
@@ -2534,8 +2551,12 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
 			categories |= PAGE_IS_SOFT_DIRTY;
 	} else {
 		categories |= PAGE_IS_SWAPPED;
-		if (!pmd_swp_uffd_wp(pmd))
-			categories |= PAGE_IS_WRITTEN;
+		if (!pmd_swp_uffd(pmd)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 		if (pmd_swp_soft_dirty(pmd))
 			categories |= PAGE_IS_SOFT_DIRTY;
 
@@ -2558,17 +2579,18 @@ static void make_uffd_wp_pmd(struct vm_area_struct *vma,
 
 	if (pmd_present(pmd)) {
 		old = pmdp_invalidate_ad(vma, addr, pmdp);
-		pmd = pmd_mkuffd_wp(old);
+		pmd = pmd_mkuffd(old);
 		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
 	} else if (pmd_is_migration_entry(pmd)) {
-		pmd = pmd_swp_mkuffd_wp(pmd);
+		pmd = pmd_swp_mkuffd(pmd);
 		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
 	}
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_HUGETLB_PAGE
-static unsigned long pagemap_hugetlb_category(pte_t pte)
+static unsigned long pagemap_hugetlb_category(struct vm_area_struct *vma,
+					      pte_t pte)
 {
 	unsigned long categories = PAGE_IS_HUGE;
 
@@ -2583,8 +2605,12 @@ static unsigned long pagemap_hugetlb_category(pte_t pte)
 	if (pte_present(pte)) {
 		categories |= PAGE_IS_PRESENT;
 
-		if (!huge_pte_uffd_wp(pte))
-			categories |= PAGE_IS_WRITTEN;
+		if (!huge_pte_uffd(pte)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 		if (!PageAnon(pte_page(pte)))
 			categories |= PAGE_IS_FILE;
 		if (is_zero_pfn(pte_pfn(pte)))
@@ -2594,8 +2620,12 @@ static unsigned long pagemap_hugetlb_category(pte_t pte)
 	} else {
 		categories |= PAGE_IS_SWAPPED;
 
-		if (!pte_swp_uffd_wp_any(pte))
-			categories |= PAGE_IS_WRITTEN;
+		if (!pte_swp_uffd_any(pte)) {
+			if (userfaultfd_wp(vma))
+				categories |= PAGE_IS_WRITTEN;
+			if (userfaultfd_rwp(vma))
+				categories |= PAGE_IS_ACCESSED;
+		}
 		if (pte_swp_soft_dirty(pte))
 			categories |= PAGE_IS_SOFT_DIRTY;
 	}
@@ -2622,12 +2652,12 @@ static void make_uffd_wp_huge_pte(struct vm_area_struct *vma,
 
 	if (softleaf_is_migration(entry)) {
 		set_huge_pte_at(vma->vm_mm, addr, ptep,
-				pte_swp_mkuffd_wp(ptent), psize);
+				pte_swp_mkuffd(ptent), psize);
 	} else {
 		pte_t old_pte, new_pte;
 
 		old_pte = huge_ptep_modify_prot_start(vma, addr, ptep);
-		new_pte = huge_pte_mkuffd_wp(old_pte);
+		new_pte = huge_pte_mkuffd(old_pte);
 		huge_ptep_modify_prot_commit(vma, addr, ptep, old_pte, new_pte);
 	}
 }
@@ -2860,8 +2890,8 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
 		for (addr = start; addr != end; pte++, addr += PAGE_SIZE) {
 			pte_t ptent = ptep_get(pte);
 
-			if ((pte_present(ptent) && pte_uffd_wp(ptent)) ||
-			    pte_swp_uffd_wp_any(ptent))
+			if ((pte_present(ptent) && pte_uffd(ptent)) ||
+			    pte_swp_uffd_any(ptent))
 				continue;
 			make_uffd_wp_pte(vma, addr, pte, ptent);
 			if (!flush_end)
@@ -2871,15 +2901,16 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
 		goto flush_and_return;
 	}
 
-	if (!p->arg.category_anyof_mask && !p->arg.category_inverted &&
+	if (userfaultfd_wp(vma) && !p->arg.category_anyof_mask &&
+	    !p->arg.category_inverted &&
 	    p->arg.category_mask == PAGE_IS_WRITTEN &&
 	    p->arg.return_mask == PAGE_IS_WRITTEN) {
 		for (addr = start; addr < end; pte++, addr += PAGE_SIZE) {
 			unsigned long next = addr + PAGE_SIZE;
 			pte_t ptent = ptep_get(pte);
 
-			if ((pte_present(ptent) && pte_uffd_wp(ptent)) ||
-			    pte_swp_uffd_wp_any(ptent))
+			if ((pte_present(ptent) && pte_uffd(ptent)) ||
+			    pte_swp_uffd_any(ptent))
 				continue;
 			ret = pagemap_scan_output(p->cur_vma_category | PAGE_IS_WRITTEN,
 						  p, addr, &next);
@@ -2946,7 +2977,8 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 		/* Go the short route when not write-protecting pages. */
 
 		pte = huge_ptep_get(walk->mm, start, ptep);
-		categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
+		categories = p->cur_vma_category |
+			     pagemap_hugetlb_category(vma, pte);
 
 		if (!pagemap_scan_is_interesting_page(categories, p))
 			return 0;
@@ -2958,7 +2990,7 @@ static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
 	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, ptep);
 
 	pte = huge_ptep_get(walk->mm, start, ptep);
-	categories = p->cur_vma_category | pagemap_hugetlb_category(pte);
+	categories = p->cur_vma_category | pagemap_hugetlb_category(vma, pte);
 
 	if (!pagemap_scan_is_interesting_page(categories, p))
 		goto out_unlock;
@@ -3050,12 +3082,35 @@ static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
 {
 	struct pagemap_scan_private *p = walk->private;
 	struct vm_area_struct *vma = walk->vma;
+	unsigned long categories;
 	int ret, err;
 
-	if (!vma || !pagemap_scan_is_interesting_page(p->cur_vma_category, p))
+	if (!vma)
+		return 0;
+
+	/*
+	 * An unpopulated range with no page table -- e.g. a 2MB anon THP
+	 * dropped via MADV_DONTNEED, which pagemap_page_category() never sees
+	 * -- reads as written on a uffd-wp VMA, matching the pte_none case
+	 * there. Reporting it also lets the PM_SCAN_WP_MATCHING arming below
+	 * install markers (uffd_wp_range() allocates the page table under
+	 * WP_UNPOPULATED), so the next scan sees it clean until re-written.
+	 *
+	 * hugetlb is excluded: pagemap_hugetlb_category() reports an empty
+	 * hugetlb entry (huge_pte_none) as not-written, unlike
+	 * pagemap_page_category(), which reports pte_none as written. This
+	 * path fires for a hugetlb slot only when it has no page table;
+	 * keeping that not-written matches how an allocated-but-empty
+	 * hugetlb entry reads, so the two agree within the VMA.
+	 */
+	categories = p->cur_vma_category;
+	if (userfaultfd_wp(vma) && !is_vm_hugetlb_page(vma))
+		categories |= PAGE_IS_WRITTEN;
+
+	if (!pagemap_scan_is_interesting_page(categories, p))
 		return 0;
 
-	ret = pagemap_scan_output(p->cur_vma_category, p, addr, &end);
+	ret = pagemap_scan_output(categories, p, addr, &end);
 	if (addr == end)
 		return ret;