The patch titled
Subject: mm: replace pud_write with pud_access_permitted in fault + gup paths
has been added to the -mm tree. Its filename is
mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths.patch
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm: replace pud_write with pud_access_permitted in fault + gup paths
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.
Link: http://lkml.kernel.org/r/151043110453.2842.2166049702068628177.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 -puN arch/s390/include/asm/pgtable.h~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths arch/s390/include/asm/pgtable.h
--- a/arch/s390/include/asm/pgtable.h~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths
+++ a/arch/s390/include/asm/pgtable.h
@@ -1264,6 +1264,12 @@ static inline pud_t pud_mkwrite(pud_t pu
return pud;
}
+#define __HAVE_ARCH_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 -puN arch/sparc/mm/gup.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths arch/sparc/mm/gup.c
--- a/arch/sparc/mm/gup.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths
+++ a/arch/sparc/mm/gup.c
@@ -114,7 +114,7 @@ static int gup_huge_pud(pud_t *pudp, pud
if (!(pud_val(pud) & _PAGE_VALID))
return 0;
- if (write && !pud_write(pud))
+ if (!pud_access_permitted(pud, write))
return 0;
refs = 0;
diff -puN mm/huge_memory.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths mm/huge_memory.c
--- a/mm/huge_memory.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths
+++ a/mm/huge_memory.c
@@ -1022,7 +1022,7 @@ struct page *follow_devmap_pud(struct vm
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 -puN mm/memory.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths mm/memory.c
--- a/mm/memory.c~mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths
+++ a/mm/memory.c
@@ -4013,7 +4013,7 @@ static int __handle_mm_fault(struct vm_a
/* 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;
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
mm-fix-device-dax-pud-write-faults-triggered-by-get_user_pages.patch
mm-replace-pud_write-with-pud_access_permitted-in-fault-gup-paths.patch
mm-replace-pmd_write-with-pmd_access_permitted-in-fault-gup-paths.patch
mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch
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