* + mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch added to -mm tree
@ 2017-11-14 20:22 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2017-11-14 20:22 UTC (permalink / raw)
To: dan.j.williams, dave.hansen, jglisse, kirill.shutemov, mm-commits
The patch titled
Subject: mm: replace pte_write with pte_access_permitted in fault + gup paths
has been added to the -mm tree. Its filename is
mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch
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From: Dan Williams <dan.j.williams@intel.com>
Subject: mm: replace pte_write with pte_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
pte_write is must be referencing user-memory.
Link: http://lkml.kernel.org/r/151043111604.2842.8051684481794973100.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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: Andrew Morton <akpm@linux-foundation.org>
---
mm/gup.c | 2 +-
mm/hmm.c | 4 ++--
mm/memory.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)
diff -puN mm/gup.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths mm/gup.c
--- a/mm/gup.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths
+++ a/mm/gup.c
@@ -66,7 +66,7 @@ static int follow_pfn_pte(struct vm_area
*/
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 -puN mm/hmm.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths mm/hmm.c
--- a/mm/hmm.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths
+++ a/mm/hmm.c
@@ -456,11 +456,11 @@ again:
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 -puN mm/memory.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths mm/memory.c
--- a/mm/memory.c~mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths
+++ a/mm/memory.c
@@ -3948,7 +3948,7 @@ static int handle_pte_fault(struct vm_fa
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 *v
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));
_
Patches currently in -mm which might be from dan.j.williams@intel.com 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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2017-11-14 20:22 + mm-replace-pte_write-with-pte_access_permitted-in-fault-gup-paths.patch added to -mm tree akpm
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