[PATCH 3/3] x86: mm: add x86_64 support for page table check

From: Pasha Tatashin
Date: Tue Nov 23 2021 - 16:49:01 EST


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 {
--
2.34.0.rc2.393.gf8c9666880-goog