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mm: replace pmd_write with pmd_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
   pmd_write is must be referencing user-memory.

Link: http://lkml.kernel.org/r/151043111049.2842.15241454964150083466.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 16:10:18 -08:00 committed by Linus Torvalds
parent e7fe7b5cae
commit c7da82b894
5 changed files with 8 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/sparc/mm/gup.c
View File

@ -75,7 +75,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
if (!(pmd_val(pmd) & _PAGE_VALID))
return 0;
if (write && !pmd_write(pmd))
if (!pmd_access_permitted(pmd, write))
return 0;
refs = 0;

3
fs/dax.c
View File

@ -627,7 +627,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
if (pfn != pmd_pfn(*pmdp))
goto unlock_pmd;
if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
if (!pmd_dirty(*pmdp)
&& !pmd_access_permitted(*pmdp, WRITE))
goto unlock_pmd;
flush_cache_page(vma, address, pfn);

4
mm/hmm.c
View File

@ -391,11 +391,11 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
if (pmd_protnone(pmd))
return hmm_vma_walk_clear(start, end, walk);
if (write_fault && !pmd_write(pmd))
if (!pmd_access_permitted(pmd, write_fault))
return hmm_vma_walk_clear(start, end, walk);
pfn = pmd_pfn(pmd) + pte_index(addr);
flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
flag |= pmd_access_permitted(pmd, WRITE) ? HMM_PFN_WRITE : 0;
for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
return 0;

4
mm/huge_memory.c
View File

@ -877,7 +877,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
*/
WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
if (flags & FOLL_WRITE && !pmd_write(*pmd))
if (!pmd_access_permitted(*pmd, flags & FOLL_WRITE))
return NULL;
if (pmd_present(*pmd) && pmd_devmap(*pmd))
@ -1393,7 +1393,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
*/
static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
{
return pmd_write(pmd) ||
return pmd_access_permitted(pmd, WRITE) ||
((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
}

2
mm/memory.c
View File

@ -4046,7 +4046,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
return do_huge_pmd_numa_page(&vmf, orig_pmd);
if (dirty && !pmd_write(orig_pmd)) {
if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) {
ret = wp_huge_pmd(&vmf, orig_pmd);
if (!(ret & VM_FAULT_FALLBACK))
return ret;