[PATCH v2 4/4] x86: mm: add x86_64 support for page table check

[Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>]

Add page table check hooks into routines that modify user page tables.

Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
---
 arch/x86/Kconfig               |  1 +
 arch/x86/include/asm/pgtable.h | 29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5e16393d9988..7636ea400a71 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -104,6 +104,7 @@ config X86
 	select ARCH_SUPPORTS_ACPI
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
+	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if X86_64
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
 	select ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP	if NR_CPUS <= 4096
 	select ARCH_SUPPORTS_LTO_CLANG
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 448cd01eb3ec..ae34614b7e8d 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -26,6 +26,7 @@
 #include <asm/pkru.h>
 #include <asm/fpu/api.h>
 #include <asm-generic/pgtable_uffd.h>
+#include <linux/page_table_check.h>
 
 extern pgd_t early_top_pgt[PTRS_PER_PGD];
 bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
@@ -1006,18 +1007,21 @@ static inline pud_t native_local_pudp_get_and_clear(pud_t *pudp)
 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep, pte_t pte)
 {
+	page_table_check_pte_set(mm, addr, ptep, pte);
 	set_pte(ptep, pte);
 }
 
 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 			      pmd_t *pmdp, pmd_t pmd)
 {
+	page_table_check_pmd_set(mm, addr, pmdp, pmd);
 	set_pmd(pmdp, pmd);
 }
 
 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
 			      pud_t *pudp, pud_t pud)
 {
+	page_table_check_pud_set(mm, addr, pudp, pud);
 	native_set_pud(pudp, pud);
 }
 
@@ -1048,6 +1052,7 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pte_t *ptep)
 {
 	pte_t pte = native_ptep_get_and_clear(ptep);
+	page_table_check_pte_clear(mm, addr, pte);
 	return pte;
 }
 
@@ -1063,12 +1068,23 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 		 * care about updates and native needs no locking
 		 */
 		pte = native_local_ptep_get_and_clear(ptep);
+		page_table_check_pte_clear(mm, addr, pte);
 	} else {
 		pte = ptep_get_and_clear(mm, addr, ptep);
 	}
 	return pte;
 }
 
+#define __HAVE_ARCH_PTEP_CLEAR
+static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
+			      pte_t *ptep)
+{
+	if (IS_ENABLED(CONFIG_PAGE_TABLE_CHECK))
+		ptep_get_and_clear(mm, addr, ptep);
+	else
+		pte_clear(mm, addr, ptep);
+}
+
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 static inline void ptep_set_wrprotect(struct mm_struct *mm,
 				      unsigned long addr, pte_t *ptep)
@@ -1109,14 +1125,22 @@ static inline int pmd_write(pmd_t pmd)
 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pmd_t *pmdp)
 {
-	return native_pmdp_get_and_clear(pmdp);
+	pmd_t pmd = native_pmdp_get_and_clear(pmdp);
+
+	page_table_check_pmd_clear(mm, addr, pmd);
+
+	return pmd;
 }
 
 #define __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
 					unsigned long addr, pud_t *pudp)
 {
-	return native_pudp_get_and_clear(pudp);
+	pud_t pud = native_pudp_get_and_clear(pudp);
+
+	page_table_check_pud_clear(mm, addr, pud);
+
+	return pud;
 }
 
 #define __HAVE_ARCH_PMDP_SET_WRPROTECT
@@ -1137,6 +1161,7 @@ static inline int pud_write(pud_t pud)
 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 		unsigned long address, pmd_t *pmdp, pmd_t pmd)
 {
+	page_table_check_pmd_set(vma->vm_mm, address, pmdp, pmd);
 	if (IS_ENABLED(CONFIG_SMP)) {
 		return xchg(pmdp, pmd);
 	} else {
-- 
2.34.1.400.ga245620fadb-goog