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mm: replace pte_write with pte_access_permitted in fault + gup paths

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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>
This commit is contained in:
Dan Williams 2017-11-29 16:10:21 -08:00 committed by Linus Torvalds
parent c7da82b894
commit 5c9d2d5c26
3 changed files with 5 additions and 5 deletions
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2
mm/gup.c
View File

@ -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));
}

4
mm/hmm.c
View File

@ -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:

4
mm/memory.c
View File

@ -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));