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* [PATCH v3 0/5] fix device-dax pud crash and fixup {pte, pmd, pud}_write
@ 2017-11-21 19:07 ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Dave Hansen, Stephen Rothwell, Chris Metcalf, Arnd Bergmann,
	linux-nvdimm, Benjamin Herrenschmidt, x86, Heiko Carstens,
	Russell King, Ralf Baechle, linux-mm, Jérôme Glisse,
	Ingo Molnar, stable, H. Peter Anvin, Martin Schwidefsky,
	Thomas Gleixner, David S. Miller, Kirill A. Shutemov

Changes since v2 [1]:
* Switch from the "#define __HAVE_ARCH_PUD_WRITE" to "#define
  pud_write". This incidentally fixes a powerpc compile error.
  (Stephen)

* Add a cleanup patch to align pmd_write to the pud_write definition
  scheme.

---

Andrew,

Here is another attempt at the pud_write() fix [2], and some follow-on
patches to use the '_access_permitted' helpers in fault and
get_user_pages() paths where we are checking if the thread has access to
write. I explicitly omit conversions for places where the kernel is
checking the _PAGE_RW flag for kernel purposes, not for userspace
access.

Beyond fixing the crash, this series also fixes get_user_pages() and
fault paths to honor protection keys in the same manner as
get_user_pages_fast(). Only the crash fix is tagged for -stable as the
protection key check is done just for consistency reasons since
userspace can change protection keys at will.

These have received a build success notification from the 0day robot.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2017-November/013254.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2017-November/013237.html

---

Dan Williams (5):
      mm: fix device-dax pud write-faults triggered by get_user_pages()
      mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE
      mm: replace pud_write with pud_access_permitted in fault + gup paths
      mm: replace pmd_write with pmd_access_permitted in fault + gup paths
      mm: replace pte_write with pte_access_permitted in fault + gup paths


 arch/arm/include/asm/pgtable-3level.h        |    1 -
 arch/arm64/include/asm/pgtable.h             |    1 -
 arch/mips/include/asm/pgtable.h              |    2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |    1 -
 arch/s390/include/asm/pgtable.h              |    8 +++++++-
 arch/sparc/include/asm/pgtable_64.h          |    2 +-
 arch/sparc/mm/gup.c                          |    4 ++--
 arch/tile/include/asm/pgtable.h              |    1 -
 arch/x86/include/asm/pgtable.h               |    8 +++++++-
 fs/dax.c                                     |    3 ++-
 include/asm-generic/pgtable.h                |   12 ++++++++++--
 include/linux/hugetlb.h                      |    8 --------
 mm/gup.c                                     |    2 +-
 mm/hmm.c                                     |    8 ++++----
 mm/huge_memory.c                             |    6 +++---
 mm/memory.c                                  |    8 ++++----
 16 files changed, 42 insertions(+), 33 deletions(-)
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^ permalink raw reply	[flat|nested] 13+ messages in thread
* [PATCH v3 0/5] fix device-dax pud crash and fixup {pte, pmd, pud}_write
@ 2017-11-21 19:07 ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Stephen Rothwell, Chris Metcalf, Arnd Bergmann, linux-nvdimm,
	Benjamin Herrenschmidt, x86, Heiko Carstens, Russell King,
	Ralf Baechle, linux-mm, Dave Hansen, Jérôme Glisse,
	Ingo Molnar, stable, H. Peter Anvin, Martin Schwidefsky,
	Thomas Gleixner, David S. Miller, Kirill A. Shutemov

Changes since v2 [1]:
* Switch from the "#define __HAVE_ARCH_PUD_WRITE" to "#define
  pud_write". This incidentally fixes a powerpc compile error.
  (Stephen)

* Add a cleanup patch to align pmd_write to the pud_write definition
  scheme.

---

Andrew,

Here is another attempt at the pud_write() fix [2], and some follow-on
patches to use the '_access_permitted' helpers in fault and
get_user_pages() paths where we are checking if the thread has access to
write. I explicitly omit conversions for places where the kernel is
checking the _PAGE_RW flag for kernel purposes, not for userspace
access.

Beyond fixing the crash, this series also fixes get_user_pages() and
fault paths to honor protection keys in the same manner as
get_user_pages_fast(). Only the crash fix is tagged for -stable as the
protection key check is done just for consistency reasons since
userspace can change protection keys at will.

These have received a build success notification from the 0day robot.

[1]: https://lists.01.org/pipermail/linux-nvdimm/2017-November/013254.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2017-November/013237.html

---

Dan Williams (5):
      mm: fix device-dax pud write-faults triggered by get_user_pages()
      mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE
      mm: replace pud_write with pud_access_permitted in fault + gup paths
      mm: replace pmd_write with pmd_access_permitted in fault + gup paths
      mm: replace pte_write with pte_access_permitted in fault + gup paths


 arch/arm/include/asm/pgtable-3level.h        |    1 -
 arch/arm64/include/asm/pgtable.h             |    1 -
 arch/mips/include/asm/pgtable.h              |    2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |    1 -
 arch/s390/include/asm/pgtable.h              |    8 +++++++-
 arch/sparc/include/asm/pgtable_64.h          |    2 +-
 arch/sparc/mm/gup.c                          |    4 ++--
 arch/tile/include/asm/pgtable.h              |    1 -
 arch/x86/include/asm/pgtable.h               |    8 +++++++-
 fs/dax.c                                     |    3 ++-
 include/asm-generic/pgtable.h                |   12 ++++++++++--
 include/linux/hugetlb.h                      |    8 --------
 mm/gup.c                                     |    2 +-
 mm/hmm.c                                     |    8 ++++----
 mm/huge_memory.c                             |    6 +++---
 mm/memory.c                                  |    8 ++++----
 16 files changed, 42 insertions(+), 33 deletions(-)

--
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^ permalink raw reply	[flat|nested] 13+ messages in thread
* [PATCH v3 1/5] mm: fix device-dax pud write-faults triggered by get_user_pages()
  2017-11-21 19:07 ` Dan Williams
@ 2017-11-21 19:07   ` Dan Williams
  -1 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Stephen Rothwell, Arnd Bergmann, linux-nvdimm, x86, Dave Hansen,
	stable, linux-mm, Ingo Molnar, H. Peter Anvin, Thomas Gleixner,
	Kirill A. Shutemov

Currently only get_user_pages_fast() can safely handle the writable gup
case due to its use of pud_access_permitted() to check whether the pud
entry is writable. In the gup slow path pud_write() is used instead of
pud_access_permitted() and to date it has been unimplemented, just calls
BUG_ON().

    kernel BUG at ./include/linux/hugetlb.h:244!
    [..]
    RIP: 0010:follow_devmap_pud+0x482/0x490
    [..]
    Call Trace:
     follow_page_mask+0x28c/0x6e0
     __get_user_pages+0xe4/0x6c0
     get_user_pages_unlocked+0x130/0x1b0
     get_user_pages_fast+0x89/0xb0
     iov_iter_get_pages_alloc+0x114/0x4a0
     nfs_direct_read_schedule_iovec+0xd2/0x350
     ? nfs_start_io_direct+0x63/0x70
     nfs_file_direct_read+0x1e0/0x250
     nfs_file_read+0x90/0xc0

For now this just implements a simple check for the _PAGE_RW bit similar
to pmd_write. However, this implies that the gup-slow-path check is
missing the extra checks that the gup-fast-path performs with
pud_access_permitted. Later patches will align all checks to use the
'access_permitted' helper if the architecture provides it. Note that the
generic 'access_permitted' helper fallback is the simple _PAGE_RW check
on architectures that do not define the 'access_permitted' helper(s).

Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages")
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <stable@vger.kernel.org>
Cc: <x86@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/include/asm/pgtable.h |    6 ++++++
 include/asm-generic/pgtable.h  |    8 ++++++++
 include/linux/hugetlb.h        |    8 --------
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 09f9e1e00e3b..dcce76ee4aa7 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1088,6 +1088,12 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 	clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp);
 }
 
+#define pud_write pud_write
+static inline int pud_write(pud_t pud)
+{
+	return pud_flags(pud) & _PAGE_RW;
+}
+
 /*
  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
  *
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 757dc6ffc7ba..1ac457511f4e 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -814,6 +814,14 @@ static inline int pmd_write(pmd_t pmd)
 #endif /* __HAVE_ARCH_PMD_WRITE */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+#ifndef pud_write
+static inline int pud_write(pud_t pud)
+{
+	BUG();
+	return 0;
+}
+#endif /* pud_write */
+
 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 	(defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 	 !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index fbf5b31d47ee..82a25880714a 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -239,14 +239,6 @@ static inline int pgd_write(pgd_t pgd)
 }
 #endif
 
-#ifndef pud_write
-static inline int pud_write(pud_t pud)
-{
-	BUG();
-	return 0;
-}
-#endif
-
 #define HUGETLB_ANON_FILE "anon_hugepage"
 
 enum {

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 1/5] mm: fix device-dax pud write-faults triggered by get_user_pages()
@ 2017-11-21 19:07   ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Stephen Rothwell, Arnd Bergmann, linux-nvdimm, x86, stable,
	linux-mm, Dave Hansen, Ingo Molnar, H. Peter Anvin,
	Thomas Gleixner, Kirill A. Shutemov

Currently only get_user_pages_fast() can safely handle the writable gup
case due to its use of pud_access_permitted() to check whether the pud
entry is writable. In the gup slow path pud_write() is used instead of
pud_access_permitted() and to date it has been unimplemented, just calls
BUG_ON().

    kernel BUG at ./include/linux/hugetlb.h:244!
    [..]
    RIP: 0010:follow_devmap_pud+0x482/0x490
    [..]
    Call Trace:
     follow_page_mask+0x28c/0x6e0
     __get_user_pages+0xe4/0x6c0
     get_user_pages_unlocked+0x130/0x1b0
     get_user_pages_fast+0x89/0xb0
     iov_iter_get_pages_alloc+0x114/0x4a0
     nfs_direct_read_schedule_iovec+0xd2/0x350
     ? nfs_start_io_direct+0x63/0x70
     nfs_file_direct_read+0x1e0/0x250
     nfs_file_read+0x90/0xc0

For now this just implements a simple check for the _PAGE_RW bit similar
to pmd_write. However, this implies that the gup-slow-path check is
missing the extra checks that the gup-fast-path performs with
pud_access_permitted. Later patches will align all checks to use the
'access_permitted' helper if the architecture provides it. Note that the
generic 'access_permitted' helper fallback is the simple _PAGE_RW check
on architectures that do not define the 'access_permitted' helper(s).

Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages")
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <stable@vger.kernel.org>
Cc: <x86@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/include/asm/pgtable.h |    6 ++++++
 include/asm-generic/pgtable.h  |    8 ++++++++
 include/linux/hugetlb.h        |    8 --------
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 09f9e1e00e3b..dcce76ee4aa7 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1088,6 +1088,12 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 	clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp);
 }
 
+#define pud_write pud_write
+static inline int pud_write(pud_t pud)
+{
+	return pud_flags(pud) & _PAGE_RW;
+}
+
 /*
  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
  *
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 757dc6ffc7ba..1ac457511f4e 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -814,6 +814,14 @@ static inline int pmd_write(pmd_t pmd)
 #endif /* __HAVE_ARCH_PMD_WRITE */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+#ifndef pud_write
+static inline int pud_write(pud_t pud)
+{
+	BUG();
+	return 0;
+}
+#endif /* pud_write */
+
 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
 	(defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
 	 !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index fbf5b31d47ee..82a25880714a 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -239,14 +239,6 @@ static inline int pgd_write(pgd_t pgd)
 }
 #endif
 
-#ifndef pud_write
-static inline int pud_write(pud_t pud)
-{
-	BUG();
-	return 0;
-}
-#endif
-
 #define HUGETLB_ANON_FILE "anon_hugepage"
 
 enum {

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To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 2/5] mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE
  2017-11-21 19:07 ` Dan Williams
@ 2017-11-21 19:07   ` Dan Williams
  -1 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Stephen Rothwell, Chris Metcalf, Arnd Bergmann, linux-nvdimm,
	Benjamin Herrenschmidt, x86, Russell King, Ralf Baechle,
	linux-mm, H. Peter Anvin

In response to compile breakage introduced by a series that added the
pud_write helper to x86, Stephen notes:

    did you consider using the other paradigm:

    In arch include files:
    #define pud_write       pud_write
    static inline int pud_write(pud_t pud)
     .....

    Then in include/asm-generic/pgtable.h:

    #ifndef pud_write
    tatic inline int pud_write(pud_t pud)
    {
            ....
    }
    #endif

    If you had, then the powerpc code would have worked ... ;-) and many
    of the other interfaces in include/asm-generic/pgtable.h are
    protected that way ...

Given that some architecture already define pmd_write() as a macro,
it's a net reduction to drop the definition of
__HAVE_ARCH_PMD_WRITE.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <x86@kernel.org>
Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/arm/include/asm/pgtable-3level.h        |    1 -
 arch/arm64/include/asm/pgtable.h             |    1 -
 arch/mips/include/asm/pgtable.h              |    2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |    1 -
 arch/s390/include/asm/pgtable.h              |    2 +-
 arch/sparc/include/asm/pgtable_64.h          |    2 +-
 arch/tile/include/asm/pgtable.h              |    1 -
 arch/x86/include/asm/pgtable.h               |    2 +-
 include/asm-generic/pgtable.h                |    4 ++--
 9 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 2a029bceaf2f..1a7a17b2a1ba 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -221,7 +221,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
 }
 #define	__HAVE_ARCH_PTE_SPECIAL
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
 #define pud_page(pud)		pmd_page(__pmd(pud_val(pud)))
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index c9530b5b5ca8..149d05fb9421 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -345,7 +345,6 @@ static inline int pmd_protnone(pmd_t pmd)
 
 #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
 
 #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 9e9e94415d08..1a508a74d48d 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -552,7 +552,7 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
 extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 		       pmd_t *pmdp, pmd_t pmd);
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return !!(pmd_val(pmd) & _PAGE_WRITE);
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 9a677cd5997f..44697817ccc6 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1005,7 +1005,6 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
 #define __pmd_write(pmd)	__pte_write(pmd_pte(pmd))
 #define pmd_savedwrite(pmd)	pte_savedwrite(pmd_pte(pmd))
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index d7fe9838084d..0a6b0286c32e 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -709,7 +709,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 	return (pmd_val(pmd) & origin_mask) >> PAGE_SHIFT;
 }
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) != 0;
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 5a9e96be1665..9937c5ff94a9 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -715,7 +715,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 	return pte_pfn(pte);
 }
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline unsigned long pmd_write(pmd_t pmd)
 {
 	pte_t pte = __pte(pmd_val(pmd));
diff --git a/arch/tile/include/asm/pgtable.h b/arch/tile/include/asm/pgtable.h
index 2a26cc4fefc2..adfa21b18488 100644
--- a/arch/tile/include/asm/pgtable.h
+++ b/arch/tile/include/asm/pgtable.h
@@ -475,7 +475,6 @@ static inline void pmd_clear(pmd_t *pmdp)
 #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
 #define pmd_huge_page(pmd)	pte_huge(pmd_pte(pmd))
 #define pmd_mkhuge(pmd)		pte_pmd(pte_mkhuge(pmd_pte(pmd)))
-#define __HAVE_ARCH_PMD_WRITE
 
 #define pfn_pmd(pfn, pgprot)	pte_pmd(pfn_pte((pfn), (pgprot)))
 #define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index dcce76ee4aa7..95e2dfd75521 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1061,7 +1061,7 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 				  unsigned long address, pmd_t *pmdp);
 
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return pmd_flags(pmd) & _PAGE_RW;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 1ac457511f4e..b234d54f2cb6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -805,13 +805,13 @@ static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return 0;
 }
-#ifndef __HAVE_ARCH_PMD_WRITE
+#ifndef pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	BUG();
 	return 0;
 }
-#endif /* __HAVE_ARCH_PMD_WRITE */
+#endif /* pmd_write */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifndef pud_write

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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 2/5] mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE
@ 2017-11-21 19:07   ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: Stephen Rothwell, Chris Metcalf, Arnd Bergmann, linux-nvdimm,
	Benjamin Herrenschmidt, x86, Russell King, Ralf Baechle,
	linux-mm, H. Peter Anvin

In response to compile breakage introduced by a series that added the
pud_write helper to x86, Stephen notes:

    did you consider using the other paradigm:

    In arch include files:
    #define pud_write       pud_write
    static inline int pud_write(pud_t pud)
     .....

    Then in include/asm-generic/pgtable.h:

    #ifndef pud_write
    tatic inline int pud_write(pud_t pud)
    {
            ....
    }
    #endif

    If you had, then the powerpc code would have worked ... ;-) and many
    of the other interfaces in include/asm-generic/pgtable.h are
    protected that way ...

Given that some architecture already define pmd_write() as a macro,
it's a net reduction to drop the definition of
__HAVE_ARCH_PMD_WRITE.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <x86@kernel.org>
Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/arm/include/asm/pgtable-3level.h        |    1 -
 arch/arm64/include/asm/pgtable.h             |    1 -
 arch/mips/include/asm/pgtable.h              |    2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h |    1 -
 arch/s390/include/asm/pgtable.h              |    2 +-
 arch/sparc/include/asm/pgtable_64.h          |    2 +-
 arch/tile/include/asm/pgtable.h              |    1 -
 arch/x86/include/asm/pgtable.h               |    2 +-
 include/asm-generic/pgtable.h                |    4 ++--
 9 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 2a029bceaf2f..1a7a17b2a1ba 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -221,7 +221,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
 }
 #define	__HAVE_ARCH_PTE_SPECIAL
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
 #define pud_page(pud)		pmd_page(__pmd(pud_val(pud)))
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index c9530b5b5ca8..149d05fb9421 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -345,7 +345,6 @@ static inline int pmd_protnone(pmd_t pmd)
 
 #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
 
 #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 9e9e94415d08..1a508a74d48d 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -552,7 +552,7 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
 extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 		       pmd_t *pmdp, pmd_t pmd);
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return !!(pmd_val(pmd) & _PAGE_WRITE);
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 9a677cd5997f..44697817ccc6 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1005,7 +1005,6 @@ static inline int pmd_protnone(pmd_t pmd)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-#define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
 #define __pmd_write(pmd)	__pte_write(pmd_pte(pmd))
 #define pmd_savedwrite(pmd)	pte_savedwrite(pmd_pte(pmd))
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index d7fe9838084d..0a6b0286c32e 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -709,7 +709,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 	return (pmd_val(pmd) & origin_mask) >> PAGE_SHIFT;
 }
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) != 0;
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 5a9e96be1665..9937c5ff94a9 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -715,7 +715,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 	return pte_pfn(pte);
 }
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline unsigned long pmd_write(pmd_t pmd)
 {
 	pte_t pte = __pte(pmd_val(pmd));
diff --git a/arch/tile/include/asm/pgtable.h b/arch/tile/include/asm/pgtable.h
index 2a26cc4fefc2..adfa21b18488 100644
--- a/arch/tile/include/asm/pgtable.h
+++ b/arch/tile/include/asm/pgtable.h
@@ -475,7 +475,6 @@ static inline void pmd_clear(pmd_t *pmdp)
 #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
 #define pmd_huge_page(pmd)	pte_huge(pmd_pte(pmd))
 #define pmd_mkhuge(pmd)		pte_pmd(pte_mkhuge(pmd_pte(pmd)))
-#define __HAVE_ARCH_PMD_WRITE
 
 #define pfn_pmd(pfn, pgprot)	pte_pmd(pfn_pte((pfn), (pgprot)))
 #define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index dcce76ee4aa7..95e2dfd75521 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1061,7 +1061,7 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 				  unsigned long address, pmd_t *pmdp);
 
 
-#define __HAVE_ARCH_PMD_WRITE
+#define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	return pmd_flags(pmd) & _PAGE_RW;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 1ac457511f4e..b234d54f2cb6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -805,13 +805,13 @@ static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return 0;
 }
-#ifndef __HAVE_ARCH_PMD_WRITE
+#ifndef pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
 	BUG();
 	return 0;
 }
-#endif /* __HAVE_ARCH_PMD_WRITE */
+#endif /* pmd_write */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifndef pud_write

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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 3/5] mm: replace pud_write with pud_access_permitted in fault + gup paths
  2017-11-21 19:07 ` Dan Williams
@ 2017-11-21 19:07   ` Dan Williams
  -1 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: linux-mm, linux-nvdimm, Heiko Carstens, Dave Hansen,
	Martin Schwidefsky, David S. Miller, Kirill A. Shutemov

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pud_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/s390/include/asm/pgtable.h |    6 ++++++
 arch/sparc/mm/gup.c             |    2 +-
 mm/huge_memory.c                |    2 +-
 mm/memory.c                     |    2 +-
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 0a6b0286c32e..57d7bc92e0b8 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1264,6 +1264,12 @@ static inline pud_t pud_mkwrite(pud_t pud)
 	return pud;
 }
 
+#define pud_write pud_write
+static inline int pud_write(pud_t pud)
+{
+	return (pud_val(pud) & _REGION3_ENTRY_WRITE) != 0;
+}
+
 static inline pud_t pud_mkclean(pud_t pud)
 {
 	if (pud_large(pud)) {
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 5335ba3c850e..5ae2d0a01a70 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -114,7 +114,7 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr,
 	if (!(pud_val(pud) & _PAGE_VALID))
 		return 0;
 
-	if (write && !pud_write(pud))
+	if (!pud_access_permitted(pud, write))
 		return 0;
 
 	refs = 0;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 86fe697e8bfb..9583f035ccb0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1022,7 +1022,7 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
 
 	assert_spin_locked(pud_lockptr(mm, pud));
 
-	if (flags & FOLL_WRITE && !pud_write(*pud))
+	if (!pud_access_permitted(*pud, flags & FOLL_WRITE))
 		return NULL;
 
 	if (pud_present(*pud) && pud_devmap(*pud))
diff --git a/mm/memory.c b/mm/memory.c
index 85e7a87da79f..24fbd60eb2b0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4013,7 +4013,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 
 			/* NUMA case for anonymous PUDs would go here */
 
-			if (dirty && !pud_write(orig_pud)) {
+			if (dirty && !pud_access_permitted(orig_pud, WRITE)) {
 				ret = wp_huge_pud(&vmf, orig_pud);
 				if (!(ret & VM_FAULT_FALLBACK))
 					return ret;

_______________________________________________
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Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 3/5] mm: replace pud_write with pud_access_permitted in fault + gup paths
@ 2017-11-21 19:07   ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: linux-nvdimm, Heiko Carstens, linux-mm, Dave Hansen,
	Martin Schwidefsky, David S. Miller, Kirill A. Shutemov

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pud_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/s390/include/asm/pgtable.h |    6 ++++++
 arch/sparc/mm/gup.c             |    2 +-
 mm/huge_memory.c                |    2 +-
 mm/memory.c                     |    2 +-
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 0a6b0286c32e..57d7bc92e0b8 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1264,6 +1264,12 @@ static inline pud_t pud_mkwrite(pud_t pud)
 	return pud;
 }
 
+#define pud_write pud_write
+static inline int pud_write(pud_t pud)
+{
+	return (pud_val(pud) & _REGION3_ENTRY_WRITE) != 0;
+}
+
 static inline pud_t pud_mkclean(pud_t pud)
 {
 	if (pud_large(pud)) {
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 5335ba3c850e..5ae2d0a01a70 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -114,7 +114,7 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr,
 	if (!(pud_val(pud) & _PAGE_VALID))
 		return 0;
 
-	if (write && !pud_write(pud))
+	if (!pud_access_permitted(pud, write))
 		return 0;
 
 	refs = 0;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 86fe697e8bfb..9583f035ccb0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1022,7 +1022,7 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
 
 	assert_spin_locked(pud_lockptr(mm, pud));
 
-	if (flags & FOLL_WRITE && !pud_write(*pud))
+	if (!pud_access_permitted(*pud, flags & FOLL_WRITE))
 		return NULL;
 
 	if (pud_present(*pud) && pud_devmap(*pud))
diff --git a/mm/memory.c b/mm/memory.c
index 85e7a87da79f..24fbd60eb2b0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4013,7 +4013,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 
 			/* NUMA case for anonymous PUDs would go here */
 
-			if (dirty && !pud_write(orig_pud)) {
+			if (dirty && !pud_access_permitted(orig_pud, WRITE)) {
 				ret = wp_huge_pud(&vmf, orig_pud);
 				if (!(ret & VM_FAULT_FALLBACK))
 					return ret;

--
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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 4/5] mm: replace pmd_write with pmd_access_permitted in fault + gup paths
  2017-11-21 19:07 ` Dan Williams
@ 2017-11-21 19:07   ` Dan Williams
  -1 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: linux-mm, Jérôme Glisse, linux-nvdimm,
	Kirill A. Shutemov, Dave Hansen

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pmd_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/sparc/mm/gup.c |    2 +-
 fs/dax.c            |    3 ++-
 mm/hmm.c            |    4 ++--
 mm/huge_memory.c    |    4 ++--
 mm/memory.c         |    2 +-
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 5ae2d0a01a70..33c0f8bb0f33 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -75,7 +75,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
 	if (!(pmd_val(pmd) & _PAGE_VALID))
 		return 0;
 
-	if (write && !pmd_write(pmd))
+	if (!pmd_access_permitted(pmd, write))
 		return 0;
 
 	refs = 0;
diff --git a/fs/dax.c b/fs/dax.c
index 95981591977a..78b72c48374e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -627,7 +627,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
 
 			if (pfn != pmd_pfn(*pmdp))
 				goto unlock_pmd;
-			if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
+			if (!pmd_dirty(*pmdp)
+					&& !pmd_access_permitted(*pmdp, WRITE))
 				goto unlock_pmd;
 
 			flush_cache_page(vma, address, pfn);
diff --git a/mm/hmm.c b/mm/hmm.c
index ea19742a5d60..93718a391611 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -391,11 +391,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
 		if (pmd_protnone(pmd))
 			return hmm_vma_walk_clear(start, end, walk);
 
-		if (write_fault && !pmd_write(pmd))
+		if (!pmd_access_permitted(pmd, write_fault))
 			return hmm_vma_walk_clear(start, end, walk);
 
 		pfn = pmd_pfn(pmd) + pte_index(addr);
-		flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
+		flag |= pmd_access_permitted(pmd, WRITE) ? HMM_PFN_WRITE : 0;
 		for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
 			pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
 		return 0;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9583f035ccb0..ceeb9c4c5276 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -875,7 +875,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
 	 */
 	WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
 
-	if (flags & FOLL_WRITE && !pmd_write(*pmd))
+	if (!pmd_access_permitted(*pmd, flags & FOLL_WRITE))
 		return NULL;
 
 	if (pmd_present(*pmd) && pmd_devmap(*pmd))
@@ -1396,7 +1396,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
  */
 static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
 {
-	return pmd_write(pmd) ||
+	return pmd_access_permitted(pmd, WRITE) ||
 	       ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 24fbd60eb2b0..07eef971dbeb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4046,7 +4046,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 			if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
 				return do_huge_pmd_numa_page(&vmf, orig_pmd);
 
-			if (dirty && !pmd_write(orig_pmd)) {
+			if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) {
 				ret = wp_huge_pmd(&vmf, orig_pmd);
 				if (!(ret & VM_FAULT_FALLBACK))
 					return ret;

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https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 4/5] mm: replace pmd_write with pmd_access_permitted in fault + gup paths
@ 2017-11-21 19:07   ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:07 UTC (permalink / raw)
  To: akpm
  Cc: linux-mm, Dave Hansen, Jérôme Glisse,
	Kirill A. Shutemov, linux-nvdimm

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pmd_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "JA(C)rA'me Glisse" <jglisse@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/sparc/mm/gup.c |    2 +-
 fs/dax.c            |    3 ++-
 mm/hmm.c            |    4 ++--
 mm/huge_memory.c    |    4 ++--
 mm/memory.c         |    2 +-
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 5ae2d0a01a70..33c0f8bb0f33 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -75,7 +75,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
 	if (!(pmd_val(pmd) & _PAGE_VALID))
 		return 0;
 
-	if (write && !pmd_write(pmd))
+	if (!pmd_access_permitted(pmd, write))
 		return 0;
 
 	refs = 0;
diff --git a/fs/dax.c b/fs/dax.c
index 95981591977a..78b72c48374e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -627,7 +627,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
 
 			if (pfn != pmd_pfn(*pmdp))
 				goto unlock_pmd;
-			if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
+			if (!pmd_dirty(*pmdp)
+					&& !pmd_access_permitted(*pmdp, WRITE))
 				goto unlock_pmd;
 
 			flush_cache_page(vma, address, pfn);
diff --git a/mm/hmm.c b/mm/hmm.c
index ea19742a5d60..93718a391611 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -391,11 +391,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
 		if (pmd_protnone(pmd))
 			return hmm_vma_walk_clear(start, end, walk);
 
-		if (write_fault && !pmd_write(pmd))
+		if (!pmd_access_permitted(pmd, write_fault))
 			return hmm_vma_walk_clear(start, end, walk);
 
 		pfn = pmd_pfn(pmd) + pte_index(addr);
-		flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
+		flag |= pmd_access_permitted(pmd, WRITE) ? HMM_PFN_WRITE : 0;
 		for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
 			pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
 		return 0;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9583f035ccb0..ceeb9c4c5276 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -875,7 +875,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
 	 */
 	WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
 
-	if (flags & FOLL_WRITE && !pmd_write(*pmd))
+	if (!pmd_access_permitted(*pmd, flags & FOLL_WRITE))
 		return NULL;
 
 	if (pmd_present(*pmd) && pmd_devmap(*pmd))
@@ -1396,7 +1396,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
  */
 static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
 {
-	return pmd_write(pmd) ||
+	return pmd_access_permitted(pmd, WRITE) ||
 	       ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 24fbd60eb2b0..07eef971dbeb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4046,7 +4046,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 			if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
 				return do_huge_pmd_numa_page(&vmf, orig_pmd);
 
-			if (dirty && !pmd_write(orig_pmd)) {
+			if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) {
 				ret = wp_huge_pmd(&vmf, orig_pmd);
 				if (!(ret & VM_FAULT_FALLBACK))
 					return ret;

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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 5/5] mm: replace pte_write with pte_access_permitted in fault + gup paths
  2017-11-21 19:07 ` Dan Williams
@ 2017-11-21 19:08   ` Dan Williams
  -1 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:08 UTC (permalink / raw)
  To: akpm
  Cc: linux-mm, Jérôme Glisse, linux-nvdimm,
	Kirill A. Shutemov, Dave Hansen

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pte_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 mm/gup.c    |    2 +-
 mm/hmm.c    |    4 ++--
 mm/memory.c |    4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index dfcde13f289a..85cc822fd403 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -66,7 +66,7 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
  */
 static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
 {
-	return pte_write(pte) ||
+	return pte_access_permitted(pte, WRITE) ||
 		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
 }
 
diff --git a/mm/hmm.c b/mm/hmm.c
index 93718a391611..3a5c172af560 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -456,11 +456,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
 			continue;
 		}
 
-		if (write_fault && !pte_write(pte))
+		if (!pte_access_permitted(pte, write_fault))
 			goto fault;
 
 		pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag;
-		pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
+		pfns[i] |= pte_access_permitted(pte, WRITE) ? HMM_PFN_WRITE : 0;
 		continue;
 
 fault:
diff --git a/mm/memory.c b/mm/memory.c
index 07eef971dbeb..5eb3d2524bdc 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3948,7 +3948,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
 	if (unlikely(!pte_same(*vmf->pte, entry)))
 		goto unlock;
 	if (vmf->flags & FAULT_FLAG_WRITE) {
-		if (!pte_write(entry))
+		if (!pte_access_permitted(entry, WRITE))
 			return do_wp_page(vmf);
 		entry = pte_mkdirty(entry);
 	}
@@ -4336,7 +4336,7 @@ int follow_phys(struct vm_area_struct *vma,
 		goto out;
 	pte = *ptep;
 
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
+	if (!pte_access_permitted(pte, flags & FOLL_WRITE))
 		goto unlock;
 
 	*prot = pgprot_val(pte_pgprot(pte));

_______________________________________________
Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm

^ permalink raw reply related	[flat|nested] 13+ messages in thread
* [PATCH v3 5/5] mm: replace pte_write with pte_access_permitted in fault + gup paths
@ 2017-11-21 19:08   ` Dan Williams
  0 siblings, 0 replies; 13+ messages in thread
From: Dan Williams @ 2017-11-21 19:08 UTC (permalink / raw)
  To: akpm
  Cc: linux-mm, Dave Hansen, Jérôme Glisse,
	Kirill A. Shutemov, linux-nvdimm

The 'access_permitted' helper is used in the gup-fast path and goes
beyond the simple _PAGE_RW check to also:

* validate that the mapping is writable from a protection keys
  standpoint

* validate that the pte has _PAGE_USER set since all fault paths where
  pte_write is must be referencing user-memory.

Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "JA(C)rA'me Glisse" <jglisse@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 mm/gup.c    |    2 +-
 mm/hmm.c    |    4 ++--
 mm/memory.c |    4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index dfcde13f289a..85cc822fd403 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -66,7 +66,7 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
  */
 static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
 {
-	return pte_write(pte) ||
+	return pte_access_permitted(pte, WRITE) ||
 		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
 }
 
diff --git a/mm/hmm.c b/mm/hmm.c
index 93718a391611..3a5c172af560 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -456,11 +456,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
 			continue;
 		}
 
-		if (write_fault && !pte_write(pte))
+		if (!pte_access_permitted(pte, write_fault))
 			goto fault;
 
 		pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag;
-		pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
+		pfns[i] |= pte_access_permitted(pte, WRITE) ? HMM_PFN_WRITE : 0;
 		continue;
 
 fault:
diff --git a/mm/memory.c b/mm/memory.c
index 07eef971dbeb..5eb3d2524bdc 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3948,7 +3948,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
 	if (unlikely(!pte_same(*vmf->pte, entry)))
 		goto unlock;
 	if (vmf->flags & FAULT_FLAG_WRITE) {
-		if (!pte_write(entry))
+		if (!pte_access_permitted(entry, WRITE))
 			return do_wp_page(vmf);
 		entry = pte_mkdirty(entry);
 	}
@@ -4336,7 +4336,7 @@ int follow_phys(struct vm_area_struct *vma,
 		goto out;
 	pte = *ptep;
 
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
+	if (!pte_access_permitted(pte, flags & FOLL_WRITE))
 		goto unlock;
 
 	*prot = pgprot_val(pte_pgprot(pte));

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply related	[flat|nested] 13+ messages in thread
* Re: [PATCH v3 2/5] mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE
  2017-11-21 19:07   ` Dan Williams
  (?)
@ 2017-11-21 21:58   ` Benjamin Herrenschmidt
  -1 siblings, 0 replies; 13+ messages in thread
From: Benjamin Herrenschmidt @ 2017-11-21 21:58 UTC (permalink / raw)
  To: Dan Williams, akpm
  Cc: Stephen Rothwell, Chris Metcalf, Arnd Bergmann, linux-nvdimm,
	x86, Russell King, Ralf Baechle, linux-mm, H. Peter Anvin,
	Aneesh Kumar K.V, Oliver OHalloran

On Tue, 2017-11-21 at 11:07 -0800, Dan Williams wrote:
> In response to compile breakage introduced by a series that added the
> pud_write helper to x86, Stephen notes:

+Aneesh, +Oliver.

>     did you consider using the other paradigm:
> 
>     In arch include files:
>     #define pud_write       pud_write
>     static inline int pud_write(pud_t pud)
>      .....
> 
>     Then in include/asm-generic/pgtable.h:
> 
>     #ifndef pud_write
>     tatic inline int pud_write(pud_t pud)
>     {
>             ....
>     }
>     #endif
> 
>     If you had, then the powerpc code would have worked ... ;-) and many
>     of the other interfaces in include/asm-generic/pgtable.h are
>     protected that way ...
> 
> Given that some architecture already define pmd_write() as a macro,
> it's a net reduction to drop the definition of
> __HAVE_ARCH_PMD_WRITE.
> 
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Chris Metcalf <cmetcalf@mellanox.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: <x86@kernel.org>
> Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  arch/arm/include/asm/pgtable-3level.h        |    1 -
>  arch/arm64/include/asm/pgtable.h             |    1 -
>  arch/mips/include/asm/pgtable.h              |    2 +-
>  arch/powerpc/include/asm/book3s/64/pgtable.h |    1 -
>  arch/s390/include/asm/pgtable.h              |    2 +-
>  arch/sparc/include/asm/pgtable_64.h          |    2 +-
>  arch/tile/include/asm/pgtable.h              |    1 -
>  arch/x86/include/asm/pgtable.h               |    2 +-
>  include/asm-generic/pgtable.h                |    4 ++--
>  9 files changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
> index 2a029bceaf2f..1a7a17b2a1ba 100644
> --- a/arch/arm/include/asm/pgtable-3level.h
> +++ b/arch/arm/include/asm/pgtable-3level.h
> @@ -221,7 +221,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
>  }
>  #define	__HAVE_ARCH_PTE_SPECIAL
>  
> -#define __HAVE_ARCH_PMD_WRITE
>  #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
>  #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
>  #define pud_page(pud)		pmd_page(__pmd(pud_val(pud)))
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index c9530b5b5ca8..149d05fb9421 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -345,7 +345,6 @@ static inline int pmd_protnone(pmd_t pmd)
>  
>  #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))
>  
> -#define __HAVE_ARCH_PMD_WRITE
>  #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
>  
>  #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index 9e9e94415d08..1a508a74d48d 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -552,7 +552,7 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
>  extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
>  		       pmd_t *pmdp, pmd_t pmd);
>  
> -#define __HAVE_ARCH_PMD_WRITE
> +#define pmd_write pmd_write
>  static inline int pmd_write(pmd_t pmd)
>  {
>  	return !!(pmd_val(pmd) & _PAGE_WRITE);
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 9a677cd5997f..44697817ccc6 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -1005,7 +1005,6 @@ static inline int pmd_protnone(pmd_t pmd)
>  }
>  #endif /* CONFIG_NUMA_BALANCING */
>  
> -#define __HAVE_ARCH_PMD_WRITE
>  #define pmd_write(pmd)		pte_write(pmd_pte(pmd))
>  #define __pmd_write(pmd)	__pte_write(pmd_pte(pmd))
>  #define pmd_savedwrite(pmd)	pte_savedwrite(pmd_pte(pmd))
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index d7fe9838084d..0a6b0286c32e 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -709,7 +709,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
>  	return (pmd_val(pmd) & origin_mask) >> PAGE_SHIFT;
>  }
>  
> -#define __HAVE_ARCH_PMD_WRITE
> +#define pmd_write pmd_write
>  static inline int pmd_write(pmd_t pmd)
>  {
>  	return (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) != 0;
> diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
> index 5a9e96be1665..9937c5ff94a9 100644
> --- a/arch/sparc/include/asm/pgtable_64.h
> +++ b/arch/sparc/include/asm/pgtable_64.h
> @@ -715,7 +715,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
>  	return pte_pfn(pte);
>  }
>  
> -#define __HAVE_ARCH_PMD_WRITE
> +#define pmd_write pmd_write
>  static inline unsigned long pmd_write(pmd_t pmd)
>  {
>  	pte_t pte = __pte(pmd_val(pmd));
> diff --git a/arch/tile/include/asm/pgtable.h b/arch/tile/include/asm/pgtable.h
> index 2a26cc4fefc2..adfa21b18488 100644
> --- a/arch/tile/include/asm/pgtable.h
> +++ b/arch/tile/include/asm/pgtable.h
> @@ -475,7 +475,6 @@ static inline void pmd_clear(pmd_t *pmdp)
>  #define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
>  #define pmd_huge_page(pmd)	pte_huge(pmd_pte(pmd))
>  #define pmd_mkhuge(pmd)		pte_pmd(pte_mkhuge(pmd_pte(pmd)))
> -#define __HAVE_ARCH_PMD_WRITE
>  
>  #define pfn_pmd(pfn, pgprot)	pte_pmd(pfn_pte((pfn), (pgprot)))
>  #define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index dcce76ee4aa7..95e2dfd75521 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1061,7 +1061,7 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
>  				  unsigned long address, pmd_t *pmdp);
>  
>  
> -#define __HAVE_ARCH_PMD_WRITE
> +#define pmd_write pmd_write
>  static inline int pmd_write(pmd_t pmd)
>  {
>  	return pmd_flags(pmd) & _PAGE_RW;
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index 1ac457511f4e..b234d54f2cb6 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -805,13 +805,13 @@ static inline int pmd_trans_huge(pmd_t pmd)
>  {
>  	return 0;
>  }
> -#ifndef __HAVE_ARCH_PMD_WRITE
> +#ifndef pmd_write
>  static inline int pmd_write(pmd_t pmd)
>  {
>  	BUG();
>  	return 0;
>  }
> -#endif /* __HAVE_ARCH_PMD_WRITE */
> +#endif /* pmd_write */
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  
>  #ifndef pud_write

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^ permalink raw reply	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2017-11-21 21:58 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-11-21 19:07 [PATCH v3 0/5] fix device-dax pud crash and fixup {pte, pmd, pud}_write Dan Williams
2017-11-21 19:07 ` Dan Williams
2017-11-21 19:07 ` [PATCH v3 1/5] mm: fix device-dax pud write-faults triggered by get_user_pages() Dan Williams
2017-11-21 19:07   ` Dan Williams
2017-11-21 19:07 ` [PATCH v3 2/5] mm: switch to 'define pmd_write' instead of __HAVE_ARCH_PMD_WRITE Dan Williams
2017-11-21 19:07   ` Dan Williams
2017-11-21 21:58   ` Benjamin Herrenschmidt
2017-11-21 19:07 ` [PATCH v3 3/5] mm: replace pud_write with pud_access_permitted in fault + gup paths Dan Williams
2017-11-21 19:07   ` Dan Williams
2017-11-21 19:07 ` [PATCH v3 4/5] mm: replace pmd_write with pmd_access_permitted " Dan Williams
2017-11-21 19:07   ` Dan Williams
2017-11-21 19:08 ` [PATCH v3 5/5] mm: replace pte_write with pte_access_permitted " Dan Williams
2017-11-21 19:08   ` Dan Williams

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