Re: [PATCH -next v5 4/5] arm64: mm: add support for page table check
From: Tong Tiangen
Date: Sun Apr 24 2022 - 00:15:01 EST
在 2022/4/22 14:45, Anshuman Khandual 写道:
Please change the subject line as
arm64/mm: Enable ARCH_SUPPORTS_PAGE_TABLE_CHECK
OR
arm64/mm: Subscribe ARCH_SUPPORTS_PAGE_TABLE_CHECK
On 4/21/22 13:50, Tong Tiangen wrote:
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
As commit d283d422c6c4 ("x86: mm: add x86_64 support for page table
check"), add some necessary page table check hooks into routines that
modify user page tables.
Please make the commit message comprehensive, which should include
- Enabling ARCH_SUPPORTS_PAGE_TABLE_CHECK on arm64
- Adding all additional page table helpers required for PAGE_TABLE_CHECK
- Instrumenting existing page table helpers with page table check hooks
Good suggestion, if i need to do a new version for some other reason i
think it should be described more comprehensively.
Thanks,
Tong.
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
Reviewed-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/pgtable.h | 65 +++++++++++++++++++++++++++++---
2 files changed, 61 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 18a18a0e855d..c1509525ab8e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -92,6 +92,7 @@ config ARM64
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select ARCH_SUPPORTS_NUMA_BALANCING
+ select ARCH_SUPPORTS_PAGE_TABLE_CHECK
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 930077f7b572..9f8f97a7cc7c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -33,6 +33,7 @@
#include <linux/mmdebug.h>
#include <linux/mm_types.h>
#include <linux/sched.h>
+#include <linux/page_table_check.h>
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
@@ -96,6 +97,7 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
#define pte_young(pte) (!!(pte_val(pte) & PTE_AF))
#define pte_special(pte) (!!(pte_val(pte) & PTE_SPECIAL))
#define pte_write(pte) (!!(pte_val(pte) & PTE_WRITE))
+#define pte_user(pte) (!!(pte_val(pte) & PTE_USER))
#define pte_user_exec(pte) (!(pte_val(pte) & PTE_UXN))
#define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT))
#define pte_devmap(pte) (!!(pte_val(pte) & PTE_DEVMAP))
@@ -312,7 +314,7 @@ static inline void __check_racy_pte_update(struct mm_struct *mm, pte_t *ptep,
__func__, pte_val(old_pte), pte_val(pte));
}
-static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
+static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte))
@@ -343,6 +345,13 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
set_pte(ptep, pte);
}
+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);
+ return __set_pte_at(mm, addr, ptep, pte);
+}
+
/*
* Huge pte definitions.
*/
@@ -454,6 +463,8 @@ static inline int pmd_trans_huge(pmd_t pmd)
#define pmd_dirty(pmd) pte_dirty(pmd_pte(pmd))
#define pmd_young(pmd) pte_young(pmd_pte(pmd))
#define pmd_valid(pmd) pte_valid(pmd_pte(pmd))
+#define pmd_user(pmd) pte_user(pmd_pte(pmd))
+#define pmd_user_exec(pmd) pte_user_exec(pmd_pte(pmd))
#define pmd_cont(pmd) pte_cont(pmd_pte(pmd))
#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
#define pmd_mkold(pmd) pte_pmd(pte_mkold(pmd_pte(pmd)))
@@ -501,8 +512,19 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd)
#define pud_pfn(pud) ((__pud_to_phys(pud) & PUD_MASK) >> PAGE_SHIFT)
#define pfn_pud(pfn,prot) __pud(__phys_to_pud_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
-#define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
-#define set_pud_at(mm, addr, pudp, pud) set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud))
+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);
+ return __set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(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);
+ return __set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud));
+}
#define __p4d_to_phys(p4d) __pte_to_phys(p4d_pte(p4d))
#define __phys_to_p4d_val(phys) __phys_to_pte_val(phys)
@@ -643,6 +665,24 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
#define pud_present(pud) pte_present(pud_pte(pud))
#define pud_leaf(pud) pud_sect(pud)
#define pud_valid(pud) pte_valid(pud_pte(pud))
+#define pud_user(pud) pte_user(pud_pte(pud))
+
+#ifdef CONFIG_PAGE_TABLE_CHECK
+static inline bool pte_user_accessible_page(pte_t pte)
+{
+ return pte_present(pte) && (pte_user(pte) || pte_user_exec(pte));
+}
+
+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+ return pmd_present(pmd) && (pmd_user(pmd) || pmd_user_exec(pmd));
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+ return pud_present(pud) && pud_user(pud);
+}
+#endif
static inline void set_pud(pud_t *pudp, pud_t pud)
{
@@ -872,11 +912,21 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+static inline pte_t __ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long address, pte_t *ptep)
+{
+ return __pte(xchg_relaxed(&pte_val(*ptep), 0));
+}
+
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
unsigned long address, pte_t *ptep)
{
- return __pte(xchg_relaxed(&pte_val(*ptep), 0));
+ pte_t pte = __ptep_get_and_clear(mm, address, ptep);
__ptep_get_and_clear() is not required. Please keep the __pte(xchg_relaxed(..),..)
unchanged as in the case with pmdp_huge_get_and_clear() helper below.
+
+ page_table_check_pte_clear(mm, address, pte);
+
+ return pte;
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -884,7 +934,11 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
unsigned long address, pmd_t *pmdp)
{
- return pte_pmd(ptep_get_and_clear(mm, address, (pte_t *)pmdp));
+ pmd_t pmd = pte_pmd(__ptep_get_and_clear(mm, address, (pte_t *)pmdp));
+
+ page_table_check_pmd_clear(mm, address, pmd);
+
+ return pmd;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
@@ -918,6 +972,7 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
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);
return __pmd(xchg_relaxed(&pmd_val(*pmdp), pmd_val(pmd)));
}
#endif
.