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>
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@ -75,7 +75,7 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
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if (!(pmd_val(pmd) & _PAGE_VALID))
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return 0;
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if (write && !pmd_write(pmd))
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if (!pmd_access_permitted(pmd, write))
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return 0;
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refs = 0;
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3
fs/dax.c
3
fs/dax.c
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@ -627,7 +627,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
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if (pfn != pmd_pfn(*pmdp))
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goto unlock_pmd;
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if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
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if (!pmd_dirty(*pmdp)
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&& !pmd_access_permitted(*pmdp, WRITE))
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goto unlock_pmd;
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flush_cache_page(vma, address, pfn);
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4
mm/hmm.c
4
mm/hmm.c
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@ -391,11 +391,11 @@ again:
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if (pmd_protnone(pmd))
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return hmm_vma_walk_clear(start, end, walk);
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if (write_fault && !pmd_write(pmd))
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if (!pmd_access_permitted(pmd, write_fault))
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return hmm_vma_walk_clear(start, end, walk);
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pfn = pmd_pfn(pmd) + pte_index(addr);
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flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
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flag |= pmd_access_permitted(pmd, WRITE) ? HMM_PFN_WRITE : 0;
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for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
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pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
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return 0;
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@ -877,7 +877,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
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*/
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WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
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if (flags & FOLL_WRITE && !pmd_write(*pmd))
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if (!pmd_access_permitted(*pmd, flags & FOLL_WRITE))
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return NULL;
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if (pmd_present(*pmd) && pmd_devmap(*pmd))
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@ -1393,7 +1393,7 @@ out_unlock:
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*/
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static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
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{
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return pmd_write(pmd) ||
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return pmd_access_permitted(pmd, WRITE) ||
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((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
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}
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@ -4046,7 +4046,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
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if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
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return do_huge_pmd_numa_page(&vmf, orig_pmd);
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if (dirty && !pmd_write(orig_pmd)) {
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if (dirty && !pmd_access_permitted(orig_pmd, WRITE)) {
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ret = wp_huge_pmd(&vmf, orig_pmd);
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if (!(ret & VM_FAULT_FALLBACK))
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return ret;
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