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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/gup.c b/mm/gup.c
index dfcde13f289a76ddcb54919f900467aeab15609d..85cc822fd403c50a46e773f118c1554c68158913 100644 (file)
--- 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 93718a39161191e837ff097088611f0cf6e611f0..3a5c172af56039bb26007ea4cc5ec4ca0a9bf659 100644 (file)
--- a/mm/hmm.c
+++ b/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 --git a/mm/memory.c b/mm/memory.c
index 416e451a707e2a8d064d5817cd477191ed945abc..4f07acd1695fb9991d0f5de2c3cec23a7dc78eaf 100644 (file)
--- 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));