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>
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parent
c7da82b894
commit
5c9d2d5c26
2
mm/gup.c
2
mm/gup.c
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@ -66,7 +66,7 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
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*/
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static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
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{
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return pte_write(pte) ||
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return pte_access_permitted(pte, WRITE) ||
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((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
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}
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4
mm/hmm.c
4
mm/hmm.c
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@ -456,11 +456,11 @@ again:
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continue;
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}
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if (write_fault && !pte_write(pte))
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if (!pte_access_permitted(pte, write_fault))
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goto fault;
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pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag;
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pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
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pfns[i] |= pte_access_permitted(pte, WRITE) ? HMM_PFN_WRITE : 0;
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continue;
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fault:
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@ -3948,7 +3948,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
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if (unlikely(!pte_same(*vmf->pte, entry)))
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goto unlock;
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if (vmf->flags & FAULT_FLAG_WRITE) {
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if (!pte_write(entry))
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if (!pte_access_permitted(entry, WRITE))
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return do_wp_page(vmf);
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entry = pte_mkdirty(entry);
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}
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@ -4336,7 +4336,7 @@ int follow_phys(struct vm_area_struct *vma,
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goto out;
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pte = *ptep;
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if ((flags & FOLL_WRITE) && !pte_write(pte))
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if (!pte_access_permitted(pte, flags & FOLL_WRITE))
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goto unlock;
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*prot = pgprot_val(pte_pgprot(pte));
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