@@ -119,9 +119,9 @@ extern pmdval_t early_pmd_flags;
  * The following only work if pte_present() is true.
  * Undefined behaviour if not..
  */
-static inline int pte_dirty(pte_t pte)
+static inline bool pte_dirty(pte_t pte)
 {
-	return pte_flags(pte) & _PAGE_DIRTY;
+	return pte_flags(pte) & _PAGE_DIRTY_BITS;
 }
 
 

@@ -143,9 +143,9 @@ static inline int pte_young(pte_t pte)
 	return pte_flags(pte) & _PAGE_ACCESSED;
 }
 
-static inline int pmd_dirty(pmd_t pmd)
+static inline bool pmd_dirty(pmd_t pmd)
 {
-	return pmd_flags(pmd) & _PAGE_DIRTY;
+	return pmd_flags(pmd) & _PAGE_DIRTY_BITS;
 }
 
 static inline int pmd_young(pmd_t pmd)

@@ -153,9 +153,9 @@ static inline int pmd_young(pmd_t pmd)
 	return pmd_flags(pmd) & _PAGE_ACCESSED;
 }
 
-static inline int pud_dirty(pud_t pud)
+static inline bool pud_dirty(pud_t pud)
 {
-	return pud_flags(pud) & _PAGE_DIRTY;
+	return pud_flags(pud) & _PAGE_DIRTY_BITS;
 }
 
 static inline int pud_young(pud_t pud)

@@ -294,9 +294,23 @@ static inline pte_t pte_clear_flags(pte_t pte, pteval_t clear)
 	return native_make_pte(v & ~clear);
 }
 
+#if defined(CONFIG_X86_INTEL_SHADOW_STACK_USER)
+static inline pte_t pte_move_flags(pte_t pte, pteval_t from, pteval_t to)
+{
+	if (pte_flags(pte) & from)
+		pte = pte_set_flags(pte_clear_flags(pte, from), to);
+	return pte;
+}
+#else
+static inline pte_t pte_move_flags(pte_t pte, pteval_t from, pteval_t to)
+{
+	return pte;
+}
+#endif
+
 static inline pte_t pte_mkclean(pte_t pte)
 {
-	return pte_clear_flags(pte, _PAGE_DIRTY);
+	return pte_clear_flags(pte, _PAGE_DIRTY_BITS);
 }
 
 static inline pte_t pte_mkold(pte_t pte)

@@ -306,6 +320,7 @@ static inline pte_t pte_mkold(pte_t pte)
 
 static inline pte_t pte_wrprotect(pte_t pte)
 {
+	pte = pte_move_flags(pte, _PAGE_DIRTY_HW, _PAGE_DIRTY_SW);
 	return pte_clear_flags(pte, _PAGE_RW);
 }
 

@@ -316,9 +331,24 @@ static inline pte_t pte_mkexec(pte_t pte)
 
 static inline pte_t pte_mkdirty(pte_t pte)
 {
+	pteval_t dirty = (!IS_ENABLED(CONFIG_X86_INTEL_SHADOW_STACK_USER) ||
+			   pte_write(pte)) ? _PAGE_DIRTY_HW:_PAGE_DIRTY_SW;
+	return pte_set_flags(pte, dirty | _PAGE_SOFT_DIRTY);
+}
+
+#ifdef CONFIG_ARCH_HAS_SHSTK
+static inline pte_t pte_mkdirty_shstk(pte_t pte)
+{
+	pte = pte_clear_flags(pte, _PAGE_DIRTY_SW);
 	return pte_set_flags(pte, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
 }
 
+static inline bool pte_dirty_hw(pte_t pte)
+{
+	return pte_flags(pte) & _PAGE_DIRTY_HW;
+}
+#endif
+
 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	return pte_set_flags(pte, _PAGE_ACCESSED);

@@ -326,6 +356,7 @@ static inline pte_t pte_mkyoung(pte_t pte)
 
 static inline pte_t pte_mkwrite(pte_t pte)
 {
+	pte = pte_move_flags(pte, _PAGE_DIRTY_SW, _PAGE_DIRTY_HW);
 	return pte_set_flags(pte, _PAGE_RW);
 }
 

@@ -373,6 +404,20 @@ static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear)
 	return native_make_pmd(v & ~clear);
 }
 
+#if defined(CONFIG_X86_INTEL_SHADOW_STACK_USER)
+static inline pmd_t pmd_move_flags(pmd_t pmd, pmdval_t from, pmdval_t to)
+{
+	if (pmd_flags(pmd) & from)
+		pmd = pmd_set_flags(pmd_clear_flags(pmd, from), to);
+	return pmd;
+}
+#else
+static inline pmd_t pmd_move_flags(pmd_t pmd, pmdval_t from, pmdval_t to)
+{
+	return pmd;
+}
+#endif
+
 static inline pmd_t pmd_mkold(pmd_t pmd)
 {
 	return pmd_clear_flags(pmd, _PAGE_ACCESSED);

@@ -380,19 +425,36 @@ static inline pmd_t pmd_mkold(pmd_t pmd)
 
 static inline pmd_t pmd_mkclean(pmd_t pmd)
 {
-	return pmd_clear_flags(pmd, _PAGE_DIRTY);
+	return pmd_clear_flags(pmd, _PAGE_DIRTY_BITS);
 }
 
 static inline pmd_t pmd_wrprotect(pmd_t pmd)
 {
+	pmd = pmd_move_flags(pmd, _PAGE_DIRTY_HW, _PAGE_DIRTY_SW);
 	return pmd_clear_flags(pmd, _PAGE_RW);
 }
 
 static inline pmd_t pmd_mkdirty(pmd_t pmd)
 {
+	pmdval_t dirty = (!IS_ENABLED(CONFIG_X86_INTEL_SHADOW_STACK_USER) ||
+			  (pmd_flags(pmd) & _PAGE_RW)) ?
+			  _PAGE_DIRTY_HW:_PAGE_DIRTY_SW;
+	return pmd_set_flags(pmd, dirty | _PAGE_SOFT_DIRTY);
+}
+
+#ifdef CONFIG_ARCH_HAS_SHSTK
+static inline pmd_t pmd_mkdirty_shstk(pmd_t pmd)
+{
+	pmd = pmd_clear_flags(pmd, _PAGE_DIRTY_SW);
 	return pmd_set_flags(pmd, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
 }
 
+static inline bool pmd_dirty_hw(pmd_t pmd)
+{
+	return  pmd_flags(pmd) & _PAGE_DIRTY_HW;
+}
+#endif
+
 static inline pmd_t pmd_mkdevmap(pmd_t pmd)
 {
 	return pmd_set_flags(pmd, _PAGE_DEVMAP);

@@ -410,6 +472,7 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
 
 static inline pmd_t pmd_mkwrite(pmd_t pmd)
 {
+	pmd = pmd_move_flags(pmd, _PAGE_DIRTY_SW, _PAGE_DIRTY_HW);
 	return pmd_set_flags(pmd, _PAGE_RW);
 }
 

@@ -427,6 +490,20 @@ static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear)
 	return native_make_pud(v & ~clear);
 }
 
+#if defined(CONFIG_X86_INTEL_SHADOW_STACK_USER)
+static inline pud_t pud_move_flags(pud_t pud, pudval_t from, pudval_t to)
+{
+	if (pud_flags(pud) & from)
+		pud = pud_set_flags(pud_clear_flags(pud, from), to);
+	return pud;
+}
+#else
+static inline pud_t pud_move_flags(pud_t pud, pudval_t from, pudval_t to)
+{
+	return pud;
+}
+#endif
+
 static inline pud_t pud_mkold(pud_t pud)
 {
 	return pud_clear_flags(pud, _PAGE_ACCESSED);

@@ -434,17 +511,22 @@ static inline pud_t pud_mkold(pud_t pud)
 
 static inline pud_t pud_mkclean(pud_t pud)
 {
-	return pud_clear_flags(pud, _PAGE_DIRTY);
+	return pud_clear_flags(pud, _PAGE_DIRTY_BITS);
 }
 
 static inline pud_t pud_wrprotect(pud_t pud)
 {
+	pud = pud_move_flags(pud, _PAGE_DIRTY_HW, _PAGE_DIRTY_SW);
 	return pud_clear_flags(pud, _PAGE_RW);
 }
 
 static inline pud_t pud_mkdirty(pud_t pud)
 {
-	return pud_set_flags(pud, _PAGE_DIRTY_HW | _PAGE_SOFT_DIRTY);
+	pudval_t dirty = (!IS_ENABLED(CONFIG_X86_INTEL_SHADOW_STACK_USER) ||
+			  (pud_flags(pud) & _PAGE_RW)) ?
+			  _PAGE_DIRTY_HW:_PAGE_DIRTY_SW;
+
+	return pud_set_flags(pud, dirty | _PAGE_SOFT_DIRTY);
 }
 
 static inline pud_t pud_mkdevmap(pud_t pud)

@@ -464,6 +546,7 @@ static inline pud_t pud_mkyoung(pud_t pud)
 
 static inline pud_t pud_mkwrite(pud_t pud)
 {
+	pud = pud_move_flags(pud, _PAGE_DIRTY_SW, _PAGE_DIRTY_HW);
 	return pud_set_flags(pud, _PAGE_RW);
 }
 

@@ -595,19 +678,12 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 	val &= _PAGE_CHG_MASK;
 	val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK;
 	val = flip_protnone_guard(oldval, val, PTE_PFN_MASK);
+	if ((pte_write(pte) && !(pgprot_val(newprot) & _PAGE_RW)))
+		return pte_move_flags(__pte(val), _PAGE_DIRTY_HW,
+				      _PAGE_DIRTY_SW);
 	return __pte(val);
 }
 
-static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
-{
-	pmdval_t val = pmd_val(pmd), oldval = val;
-
-	val &= _HPAGE_CHG_MASK;
-	val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK;
-	val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK);
-	return __pmd(val);
-}
-
 /* mprotect needs to preserve PAT bits when updating vm_page_prot */
 #define pgprot_modify pgprot_modify
 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)

@@ -1159,6 +1235,19 @@ static inline int pmd_write(pmd_t pmd)
 	return pmd_flags(pmd) & _PAGE_RW;
 }
 
+static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+	pmdval_t val = pmd_val(pmd), oldval = val;
+
+	val &= _HPAGE_CHG_MASK;
+	val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK;
+	val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK);
+	if ((pmd_write(pmd) && !(pgprot_val(newprot) & _PAGE_RW)))
+		return pmd_move_flags(__pmd(val), _PAGE_DIRTY_HW,
+				      _PAGE_DIRTY_SW);
+	return __pmd(val);
+}
+
 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pmd_t *pmdp)

@@ -23,6 +23,7 @@
 #define _PAGE_BIT_SOFTW2	10	/* " */
 #define _PAGE_BIT_SOFTW3	11	/* " */
 #define _PAGE_BIT_PAT_LARGE	12	/* On 2MB or 1GB pages */
+#define _PAGE_BIT_SOFTW5	57	/* available for programmer */
 #define _PAGE_BIT_SOFTW4	58	/* available for programmer */
 #define _PAGE_BIT_PKEY_BIT0	59	/* Protection Keys, bit 1/4 */
 #define _PAGE_BIT_PKEY_BIT1	60	/* Protection Keys, bit 2/4 */

@@ -34,6 +35,7 @@
 #define _PAGE_BIT_CPA_TEST	_PAGE_BIT_SOFTW1
 #define _PAGE_BIT_SOFT_DIRTY	_PAGE_BIT_SOFTW3 /* software dirty tracking */
 #define _PAGE_BIT_DEVMAP	_PAGE_BIT_SOFTW4
+#define _PAGE_BIT_DIRTY_SW	_PAGE_BIT_SOFTW5 /* was written to */
 
 /* If _PAGE_BIT_PRESENT is clear, we use these: */
 /* - if the user mapped it with PROT_NONE; pte_present gives true */

@@ -109,6 +111,21 @@
 #define _PAGE_DEVMAP	(_AT(pteval_t, 0))
 #endif
 
+/*
+ * _PAGE_DIRTY_HW: set by the processor when a page is written.
+ * _PAGE_DIRTY_SW: a spare bit tracking a written, but now R/O page.
+ *   [R/W + _PAGE_DIRTY_HW] <-> [R/O + _PAGE_DIRTY_SW].
+ * _PAGE_SOFT_DIRTY: a spare bit used to track written pages since a time point
+ * set by the system admin; see Documentation/admin-guide/mm/soft-dirty.rst.
+ */
+#if defined(CONFIG_X86_INTEL_SHADOW_STACK_USER)
+#define _PAGE_DIRTY_SW	(_AT(pteval_t, 1) << _PAGE_BIT_DIRTY_SW)
+#else
+#define _PAGE_DIRTY_SW	(_AT(pteval_t, 0))
+#endif
+
+#define _PAGE_DIRTY_BITS (_PAGE_DIRTY_HW | _PAGE_DIRTY_SW)
+
 #define _PAGE_PROTNONE	(_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
 
 #define _PAGE_TABLE_NOENC	(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |\

@@ -122,9 +139,9 @@
  * instance, and is *not* included in this mask since
  * pte_modify() does modify it.
  */
-#define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
+#define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |			\
 			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY_HW |	\
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_DIRTY_SW | _PAGE_SOFT_DIRTY)
 #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
 
 /*