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.han...@intel.com>
Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Cc: "Jérôme Glisse" <jgli...@redhat.com>
Signed-off-by: Dan Williams <dan.j.willi...@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));
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