2022-04-21 21:57:57

by Tong Tiangen

[permalink] [raw]
Subject: [PATCH -next v5 0/5]mm: page_table_check: add support on arm64 and riscv

Page table check performs extra verifications at the time when new
pages become accessible from the userspace by getting their page
table entries (PTEs PMDs etc.) added into the table. It is supported
on X86[1].

This patchset made some simple changes and make it easier to support
new architecture, then we support this feature on ARM64 and RISCV.

[1]https://lore.kernel.org/lkml/[email protected]/

v4 -> v5:
According to Anshuman's suggestion, using PxD_SIZE instead of
PxD_PAGE_SIZE in mm/page_table_check.c and it is checked by Pasha.

v3 -> v4:
Adapt to next-20220414

v2 -> v3:
Modify ptep_clear() in include/linux/pgtable.h, using IS_ENABLED according
to the suggestions of Pasha.

v1 -> v2:
1. Fix arm64's pte/pmd/pud_user_accessible_page() according to the
suggestions of Catalin.
2. Also fix riscv's pte_pmd_pud_user_accessible_page().

Kefeng Wang (2):
mm: page_table_check: move pxx_user_accessible_page into x86
arm64: mm: add support for page table check

Tong Tiangen (3):
mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE
mm: page_table_check: add hooks to public helpers
riscv: mm: add support for page table check

arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/pgtable.h | 65 ++++++++++++++++++++++++---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/pgtable.h | 77 +++++++++++++++++++++++++++++---
arch/x86/include/asm/pgtable.h | 29 +++++++-----
include/linux/pgtable.h | 26 +++++++----
mm/page_table_check.c | 25 ++---------
7 files changed, 174 insertions(+), 50 deletions(-)

--
2.25.1


2022-04-22 05:08:56

by Tong Tiangen

[permalink] [raw]
Subject: [PATCH -next v5 5/5] riscv: mm: add support for page table check

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.

Signed-off-by: Tong Tiangen <[email protected]>
Reviewed-by: Pasha Tatashin <[email protected]>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/pgtable.h | 77 +++++++++++++++++++++++++++++---
2 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 63f7258984f3..66d241cee52c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -38,6 +38,7 @@ config RISCV
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_DEBUG_PAGEALLOC if MMU
select ARCH_SUPPORTS_HUGETLBFS if MMU
+ select ARCH_SUPPORTS_PAGE_TABLE_CHECK
select ARCH_USE_MEMTEST
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
select ARCH_WANT_FRAME_POINTERS
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 046b44225623..6f22d9580658 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -114,6 +114,8 @@
#include <asm/pgtable-32.h>
#endif /* CONFIG_64BIT */

+#include <linux/page_table_check.h>
+
#ifdef CONFIG_XIP_KERNEL
#define XIP_FIXUP(addr) ({ \
uintptr_t __a = (uintptr_t)(addr); \
@@ -315,6 +317,11 @@ static inline int pte_exec(pte_t pte)
return pte_val(pte) & _PAGE_EXEC;
}

+static inline int pte_user(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_USER;
+}
+
static inline int pte_huge(pte_t pte)
{
return pte_present(pte) && (pte_val(pte) & _PAGE_LEAF);
@@ -446,7 +453,7 @@ static inline void set_pte(pte_t *ptep, pte_t pteval)

void flush_icache_pte(pte_t pte);

-static inline void set_pte_at(struct mm_struct *mm,
+static inline void __set_pte_at(struct mm_struct *mm,
unsigned long addr, pte_t *ptep, pte_t pteval)
{
if (pte_present(pteval) && pte_exec(pteval))
@@ -455,10 +462,17 @@ static inline void set_pte_at(struct mm_struct *mm,
set_pte(ptep, pteval);
}

+static inline void set_pte_at(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep, pte_t pteval)
+{
+ page_table_check_pte_set(mm, addr, ptep, pteval);
+ __set_pte_at(mm, addr, ptep, pteval);
+}
+
static inline void pte_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
- set_pte_at(mm, addr, ptep, __pte(0));
+ __set_pte_at(mm, addr, ptep, __pte(0));
}

#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
@@ -475,11 +489,21 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma,
return true;
}

+static inline pte_t __ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long address, pte_t *ptep)
+{
+ return __pte(atomic_long_xchg((atomic_long_t *)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(atomic_long_xchg((atomic_long_t *)ptep, 0));
+ pte_t pte = __ptep_get_and_clear(mm, address, ptep);
+
+ page_table_check_pte_clear(mm, address, pte);
+
+ return pte;
}

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
@@ -546,6 +570,13 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
return ((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT);
}

+#define __pud_to_phys(pud) (pud_val(pud) >> _PAGE_PFN_SHIFT << PAGE_SHIFT)
+
+static inline unsigned long pud_pfn(pud_t pud)
+{
+ return ((__pud_to_phys(pud) & PUD_MASK) >> PAGE_SHIFT);
+}
+
static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
{
return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
@@ -567,6 +598,11 @@ static inline int pmd_young(pmd_t pmd)
return pte_young(pmd_pte(pmd));
}

+static inline int pmd_user(pmd_t pmd)
+{
+ return pte_user(pmd_pte(pmd));
+}
+
static inline pmd_t pmd_mkold(pmd_t pmd)
{
return pte_pmd(pte_mkold(pmd_pte(pmd)));
@@ -600,15 +636,39 @@ static inline pmd_t pmd_mkdirty(pmd_t pmd)
static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd)
{
- return set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd));
+ page_table_check_pmd_set(mm, addr, pmdp, pmd);
+ return __set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd));
+}
+
+static inline int pud_user(pud_t pud)
+{
+ return pte_user(pud_pte(pud));
}

static inline void set_pud_at(struct mm_struct *mm, unsigned long addr,
pud_t *pudp, pud_t pud)
{
- return set_pte_at(mm, addr, (pte_t *)pudp, pud_pte(pud));
+ page_table_check_pud_set(mm, addr, pudp, pud);
+ return __set_pte_at(mm, addr, (pte_t *)pudp, 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);
}

+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+ return pmd_leaf(pmd) && pmd_user(pmd);
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+ return pud_leaf(pud) && pud_user(pud);
+}
+#endif
+
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmd_trans_huge(pmd_t pmd)
{
@@ -634,7 +694,11 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
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;
}

#define __HAVE_ARCH_PMDP_SET_WRPROTECT
@@ -648,6 +712,7 @@ 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(atomic_long_xchg((atomic_long_t *)pmdp, pmd_val(pmd)));
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
--
2.25.1

2022-04-22 17:19:28

by Tong Tiangen

[permalink] [raw]
Subject: [PATCH -next v5 4/5] arm64: mm: add support for page table check

From: Kefeng Wang <[email protected]>

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.

Signed-off-by: Kefeng Wang <[email protected]>
Signed-off-by: Tong Tiangen <[email protected]>
Reviewed-by: Pasha Tatashin <[email protected]>
---
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);
+
+ 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
--
2.25.1

2022-04-22 17:47:36

by Tong Tiangen

[permalink] [raw]
Subject: [PATCH -next v5 1/5] mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE

Macro PUD_SIZE/PMD_SIZE is more general in various architectures. Using
PUD_SIZE/PMD_SIZE instead of PUD_PAGE_SIZE/PMD_PAGE_SIZE can better
support page table check in architectures other than x86 and it is no
functional impact on x86.

Suggested-by: Anshuman Khandual <[email protected]>
Signed-off-by: Tong Tiangen <[email protected]>
---
mm/page_table_check.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index 2458281bff89..eb0d0b71cdf6 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -177,7 +177,7 @@ void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,

if (pmd_user_accessible_page(pmd)) {
page_table_check_clear(mm, addr, pmd_pfn(pmd),
- PMD_PAGE_SIZE >> PAGE_SHIFT);
+ PMD_SIZE >> PAGE_SHIFT);
}
}
EXPORT_SYMBOL(__page_table_check_pmd_clear);
@@ -190,7 +190,7 @@ void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,

if (pud_user_accessible_page(pud)) {
page_table_check_clear(mm, addr, pud_pfn(pud),
- PUD_PAGE_SIZE >> PAGE_SHIFT);
+ PUD_SIZE >> PAGE_SHIFT);
}
}
EXPORT_SYMBOL(__page_table_check_pud_clear);
@@ -219,7 +219,7 @@ void __page_table_check_pmd_set(struct mm_struct *mm, unsigned long addr,
__page_table_check_pmd_clear(mm, addr, *pmdp);
if (pmd_user_accessible_page(pmd)) {
page_table_check_set(mm, addr, pmd_pfn(pmd),
- PMD_PAGE_SIZE >> PAGE_SHIFT,
+ PMD_SIZE >> PAGE_SHIFT,
pmd_write(pmd));
}
}
@@ -234,7 +234,7 @@ void __page_table_check_pud_set(struct mm_struct *mm, unsigned long addr,
__page_table_check_pud_clear(mm, addr, *pudp);
if (pud_user_accessible_page(pud)) {
page_table_check_set(mm, addr, pud_pfn(pud),
- PUD_PAGE_SIZE >> PAGE_SHIFT,
+ PUD_SIZE >> PAGE_SHIFT,
pud_write(pud));
}
}
--
2.25.1

2022-04-22 17:51:57

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH -next v5 1/5] mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE



On 4/21/22 13:50, Tong Tiangen wrote:
> Macro PUD_SIZE/PMD_SIZE is more general in various architectures. Using
> PUD_SIZE/PMD_SIZE instead of PUD_PAGE_SIZE/PMD_PAGE_SIZE can better
> support page table check in architectures other than x86 and it is no
> functional impact on x86.>
> Suggested-by: Anshuman Khandual <[email protected]>
> Signed-off-by: Tong Tiangen <[email protected]>

There are multiple structural problems in the commit message wording
but will leave them upto Andrew, if he could fix while merging.

Otherwise LGTM

Reviewed-by: Anshuman Khandual <[email protected]>

> ---
> mm/page_table_check.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/mm/page_table_check.c b/mm/page_table_check.c
> index 2458281bff89..eb0d0b71cdf6 100644
> --- a/mm/page_table_check.c
> +++ b/mm/page_table_check.c
> @@ -177,7 +177,7 @@ void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
>
> if (pmd_user_accessible_page(pmd)) {
> page_table_check_clear(mm, addr, pmd_pfn(pmd),
> - PMD_PAGE_SIZE >> PAGE_SHIFT);
> + PMD_SIZE >> PAGE_SHIFT);
> }
> }
> EXPORT_SYMBOL(__page_table_check_pmd_clear);
> @@ -190,7 +190,7 @@ void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,
>
> if (pud_user_accessible_page(pud)) {
> page_table_check_clear(mm, addr, pud_pfn(pud),
> - PUD_PAGE_SIZE >> PAGE_SHIFT);
> + PUD_SIZE >> PAGE_SHIFT);
> }
> }
> EXPORT_SYMBOL(__page_table_check_pud_clear);
> @@ -219,7 +219,7 @@ void __page_table_check_pmd_set(struct mm_struct *mm, unsigned long addr,
> __page_table_check_pmd_clear(mm, addr, *pmdp);
> if (pmd_user_accessible_page(pmd)) {
> page_table_check_set(mm, addr, pmd_pfn(pmd),
> - PMD_PAGE_SIZE >> PAGE_SHIFT,
> + PMD_SIZE >> PAGE_SHIFT,
> pmd_write(pmd));
> }
> }
> @@ -234,7 +234,7 @@ void __page_table_check_pud_set(struct mm_struct *mm, unsigned long addr,
> __page_table_check_pud_clear(mm, addr, *pudp);
> if (pud_user_accessible_page(pud)) {
> page_table_check_set(mm, addr, pud_pfn(pud),
> - PUD_PAGE_SIZE >> PAGE_SHIFT,
> + PUD_SIZE >> PAGE_SHIFT,
> pud_write(pud));
> }
> }

2022-04-22 18:10:18

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH -next v5 1/5] mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE

On 4/21/22 11:28, Pasha Tatashin wrote:
> On Thu, Apr 21, 2022 at 4:02 AM Tong Tiangen <[email protected]> wrote:
>>
>> Macro PUD_SIZE/PMD_SIZE is more general in various architectures. Using
>> PUD_SIZE/PMD_SIZE instead of PUD_PAGE_SIZE/PMD_PAGE_SIZE can better
>> support page table check in architectures other than x86 and it is no
>> functional impact on x86.
>>
>> Suggested-by: Anshuman Khandual <[email protected]>
>> Signed-off-by: Tong Tiangen <[email protected]>
>
> Acked-by: Pasha Tatashin <[email protected]>


To avoid similar problems in the future, please also include the following patch after the current series:

----------------8<-------------[ cut here ]------------------
From cccef7ba2433f8e97d1948f85e3bfb2ef5d32a0a Mon Sep 17 00:00:00 2001
From: Pasha Tatashin <[email protected]>
Date: Thu, 21 Apr 2022 18:04:43 +0000
Subject: [PATCH] x86: removed P*D_PAGE_MASK and P*D_PAGE_SIZE

Other architectures and the common mm/ use P*D_MASK, and P*D_SIZE.
Remove the duplicated P*D_PAGE_MASK and P*D_PAGE_SIZE which are only
used in x86/*.

Signed-off-by: Pasha Tatashin <[email protected]>
---
arch/x86/include/asm/page_types.h | 12 +++---------
arch/x86/kernel/amd_gart_64.c | 2 +-
arch/x86/kernel/head64.c | 2 +-
arch/x86/mm/mem_encrypt_boot.S | 4 ++--
arch/x86/mm/mem_encrypt_identity.c | 18 +++++++++---------
arch/x86/mm/pat/set_memory.c | 6 +++---
arch/x86/mm/pti.c | 2 +-
7 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
index a506a411474d..86bd4311daf8 100644
--- a/arch/x86/include/asm/page_types.h
+++ b/arch/x86/include/asm/page_types.h
@@ -11,20 +11,14 @@
#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))

-#define PMD_PAGE_SIZE (_AC(1, UL) << PMD_SHIFT)
-#define PMD_PAGE_MASK (~(PMD_PAGE_SIZE-1))
-
-#define PUD_PAGE_SIZE (_AC(1, UL) << PUD_SHIFT)
-#define PUD_PAGE_MASK (~(PUD_PAGE_SIZE-1))
-
#define __VIRTUAL_MASK ((1UL << __VIRTUAL_MASK_SHIFT) - 1)

-/* Cast *PAGE_MASK to a signed type so that it is sign-extended if
+/* Cast P*D_MASK to a signed type so that it is sign-extended if
virtual addresses are 32-bits but physical addresses are larger
(ie, 32-bit PAE). */
#define PHYSICAL_PAGE_MASK (((signed long)PAGE_MASK) & __PHYSICAL_MASK)
-#define PHYSICAL_PMD_PAGE_MASK (((signed long)PMD_PAGE_MASK) & __PHYSICAL_MASK)
-#define PHYSICAL_PUD_PAGE_MASK (((signed long)PUD_PAGE_MASK) & __PHYSICAL_MASK)
+#define PHYSICAL_PMD_PAGE_MASK (((signed long)PMD_MASK) & __PHYSICAL_MASK)
+#define PHYSICAL_PUD_PAGE_MASK (((signed long)PUD_MASK) & __PHYSICAL_MASK)

#define HPAGE_SHIFT PMD_SHIFT
#define HPAGE_SIZE (_AC(1,UL) << HPAGE_SHIFT)
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index ed837383de5c..02579ea02351 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -506,7 +506,7 @@ static __init unsigned long check_iommu_size(unsigned long aper, u64 aper_size)
}

a = aper + iommu_size;
- iommu_size -= round_up(a, PMD_PAGE_SIZE) - a;
+ iommu_size -= round_up(a, PMD_SIZE) - a;

if (iommu_size < 64*1024*1024) {
pr_warn("PCI-DMA: Warning: Small IOMMU %luMB."
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 4f5ecbbaae77..f11ca415e97c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -189,7 +189,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);

/* Is the address not 2M aligned? */
- if (load_delta & ~PMD_PAGE_MASK)
+ if (load_delta & ~PMD_MASK)
for (;;);

/* Activate Secure Memory Encryption (SME) if supported and enabled */
diff --git a/arch/x86/mm/mem_encrypt_boot.S b/arch/x86/mm/mem_encrypt_boot.S
index 3d1dba05fce4..640131736a19 100644
--- a/arch/x86/mm/mem_encrypt_boot.S
+++ b/arch/x86/mm/mem_encrypt_boot.S
@@ -26,7 +26,7 @@ SYM_FUNC_START(sme_encrypt_execute)
* RCX - virtual address of the encryption workarea, including:
* - stack page (PAGE_SIZE)
* - encryption routine page (PAGE_SIZE)
- * - intermediate copy buffer (PMD_PAGE_SIZE)
+ * - intermediate copy buffer (PMD_SIZE)
* R8 - physical address of the pagetables to use for encryption
*/

@@ -120,7 +120,7 @@ SYM_FUNC_START(__enc_copy)
wbinvd /* Invalidate any cache entries */

/* Copy/encrypt up to 2MB at a time */
- movq $PMD_PAGE_SIZE, %r12
+ movq $PMD_SIZE, %r12
1:
cmpq %r12, %r9
jnb 2f
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index b43bc24d2bb6..357039a38547 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -92,7 +92,7 @@ struct sme_populate_pgd_data {
* section is 2MB aligned to allow for simple pagetable setup using only
* PMD entries (see vmlinux.lds.S).
*/
-static char sme_workarea[2 * PMD_PAGE_SIZE] __section(".init.scratch");
+static char sme_workarea[2 * PMD_SIZE] __section(".init.scratch");

static char sme_cmdline_arg[] __initdata = "mem_encrypt";
static char sme_cmdline_on[] __initdata = "on";
@@ -197,8 +197,8 @@ static void __init __sme_map_range_pmd(struct sme_populate_pgd_data *ppd)
while (ppd->vaddr < ppd->vaddr_end) {
sme_populate_pgd_large(ppd);

- ppd->vaddr += PMD_PAGE_SIZE;
- ppd->paddr += PMD_PAGE_SIZE;
+ ppd->vaddr += PMD_SIZE;
+ ppd->paddr += PMD_SIZE;
}
}

@@ -224,11 +224,11 @@ static void __init __sme_map_range(struct sme_populate_pgd_data *ppd,
vaddr_end = ppd->vaddr_end;

/* If start is not 2MB aligned, create PTE entries */
- ppd->vaddr_end = ALIGN(ppd->vaddr, PMD_PAGE_SIZE);
+ ppd->vaddr_end = ALIGN(ppd->vaddr, PMD_SIZE);
__sme_map_range_pte(ppd);

/* Create PMD entries */
- ppd->vaddr_end = vaddr_end & PMD_PAGE_MASK;
+ ppd->vaddr_end = vaddr_end & PMD_MASK;
__sme_map_range_pmd(ppd);

/* If end is not 2MB aligned, create PTE entries */
@@ -324,7 +324,7 @@ void __init sme_encrypt_kernel(struct boot_params *bp)

/* Physical addresses gives us the identity mapped virtual addresses */
kernel_start = __pa_symbol(_text);
- kernel_end = ALIGN(__pa_symbol(_end), PMD_PAGE_SIZE);
+ kernel_end = ALIGN(__pa_symbol(_end), PMD_SIZE);
kernel_len = kernel_end - kernel_start;

initrd_start = 0;
@@ -354,12 +354,12 @@ void __init sme_encrypt_kernel(struct boot_params *bp)
* executable encryption area size:
* stack page (PAGE_SIZE)
* encryption routine page (PAGE_SIZE)
- * intermediate copy buffer (PMD_PAGE_SIZE)
+ * intermediate copy buffer (PMD_SIZE)
* pagetable structures for the encryption of the kernel
* pagetable structures for workarea (in case not currently mapped)
*/
execute_start = workarea_start;
- execute_end = execute_start + (PAGE_SIZE * 2) + PMD_PAGE_SIZE;
+ execute_end = execute_start + (PAGE_SIZE * 2) + PMD_SIZE;
execute_len = execute_end - execute_start;

/*
@@ -382,7 +382,7 @@ void __init sme_encrypt_kernel(struct boot_params *bp)
* before it is mapped.
*/
workarea_len = execute_len + pgtable_area_len;
- workarea_end = ALIGN(workarea_start + workarea_len, PMD_PAGE_SIZE);
+ workarea_end = ALIGN(workarea_start + workarea_len, PMD_SIZE);

/*
* Set the address to the start of where newly created pagetable
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index abf5ed76e4b7..8016d93c1288 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -714,11 +714,11 @@ phys_addr_t slow_virt_to_phys(void *__virt_addr)
switch (level) {
case PG_LEVEL_1G:
phys_addr = (phys_addr_t)pud_pfn(*(pud_t *)pte) << PAGE_SHIFT;
- offset = virt_addr & ~PUD_PAGE_MASK;
+ offset = virt_addr & ~PUD_MASK;
break;
case PG_LEVEL_2M:
phys_addr = (phys_addr_t)pmd_pfn(*(pmd_t *)pte) << PAGE_SHIFT;
- offset = virt_addr & ~PMD_PAGE_MASK;
+ offset = virt_addr & ~PMD_MASK;
break;
default:
phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
@@ -1006,7 +1006,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
case PG_LEVEL_1G:
ref_prot = pud_pgprot(*(pud_t *)kpte);
ref_pfn = pud_pfn(*(pud_t *)kpte);
- pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT;
+ pfninc = PMD_SIZE >> PAGE_SHIFT;
lpaddr = address & PUD_MASK;
lpinc = PMD_SIZE;
/*
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 5d5c7bb50ce9..a28c8d57273a 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -592,7 +592,7 @@ static void pti_set_kernel_image_nonglobal(void)
* of the image.
*/
unsigned long start = PFN_ALIGN(_text);
- unsigned long end = ALIGN((unsigned long)_end, PMD_PAGE_SIZE);
+ unsigned long end = ALIGN((unsigned long)_end, PMD_SIZE);

/*
* This clears _PAGE_GLOBAL from the entire kernel image.
--
2.36.0.rc2.479.g8af0fa9b8e-goog

2022-04-22 19:52:21

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH -next v5 4/5] arm64: mm: add support for page table check

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 <[email protected]>
>
> 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

>
> Signed-off-by: Kefeng Wang <[email protected]>
> Signed-off-by: Tong Tiangen <[email protected]>
> Reviewed-by: Pasha Tatashin <[email protected]>
> ---
> 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

2022-04-22 21:16:53

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH -next v5 1/5] mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE



On 4/22/22 00:10, Pasha Tatashin wrote:
> On 4/21/22 11:28, Pasha Tatashin wrote:
>> On Thu, Apr 21, 2022 at 4:02 AM Tong Tiangen <[email protected]> wrote:
>>> Macro PUD_SIZE/PMD_SIZE is more general in various architectures. Using
>>> PUD_SIZE/PMD_SIZE instead of PUD_PAGE_SIZE/PMD_PAGE_SIZE can better
>>> support page table check in architectures other than x86 and it is no
>>> functional impact on x86.
>>>
>>> Suggested-by: Anshuman Khandual <[email protected]>
>>> Signed-off-by: Tong Tiangen <[email protected]>
>> Acked-by: Pasha Tatashin <[email protected]>
>
> To avoid similar problems in the future, please also include the following patch after the current series:
>
> ----------------8<-------------[ cut here ]------------------
>>From cccef7ba2433f8e97d1948f85e3bfb2ef5d32a0a Mon Sep 17 00:00:00 2001
> From: Pasha Tatashin <[email protected]>
> Date: Thu, 21 Apr 2022 18:04:43 +0000
> Subject: [PATCH] x86: removed P*D_PAGE_MASK and P*D_PAGE_SIZE
>
> Other architectures and the common mm/ use P*D_MASK, and P*D_SIZE.
> Remove the duplicated P*D_PAGE_MASK and P*D_PAGE_SIZE which are only
> used in x86/*.
>
> Signed-off-by: Pasha Tatashin <[email protected]>

Absolutely, helps in minimizing arch specific stuff wrt to page table mapping.

2022-04-22 22:20:10

by Pasha Tatashin

[permalink] [raw]
Subject: Re: [PATCH -next v5 1/5] mm: page_table_check: using PxD_SIZE instead of PxD_PAGE_SIZE

On Thu, Apr 21, 2022 at 4:02 AM Tong Tiangen <[email protected]> wrote:
>
> Macro PUD_SIZE/PMD_SIZE is more general in various architectures. Using
> PUD_SIZE/PMD_SIZE instead of PUD_PAGE_SIZE/PMD_PAGE_SIZE can better
> support page table check in architectures other than x86 and it is no
> functional impact on x86.
>
> Suggested-by: Anshuman Khandual <[email protected]>
> Signed-off-by: Tong Tiangen <[email protected]>

Acked-by: Pasha Tatashin <[email protected]>

2022-04-24 16:38:38

by Tong Tiangen

[permalink] [raw]
Subject: Re: [PATCH -next v5 4/5] arm64: mm: add support for page table check



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 <[email protected]>
>>
>> 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 <[email protected]>
>> Signed-off-by: Tong Tiangen <[email protected]>
>> Reviewed-by: Pasha Tatashin <[email protected]>
>> ---
>> 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
> .

2022-04-25 09:55:43

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH -next v5 4/5] arm64: mm: add support for page table check



On 4/24/22 09:44, Tong Tiangen wrote:
>
>
> 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 <[email protected]>
>>>
>>> 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 comprehensivel


This series needs revision to accommodate earlier comments.

2022-04-25 22:23:52

by Tong Tiangen

[permalink] [raw]
Subject: Re: [PATCH -next v5 4/5] arm64: mm: add support for page table check



在 2022/4/25 13:41, Anshuman Khandual 写道:
>
>
> On 4/24/22 09:44, Tong Tiangen wrote:
>>
>>
>> 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 <[email protected]>
>>>>
>>>> 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 comprehensivel
>
>
> This series needs revision to accommodate earlier comments.
> .

OK, Thanks.