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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 <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: "Jérôme Glisse" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Dan Williams authored and Linus Torvalds committed 2017-11-29 18:40:42 -08:00
1 parent c7da82b894
commit 5c9d2d5c26
3 files changed
+5 -5
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mm/gup.c
+1 -1
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));
}
mm/hmm.c
+2 -2
View File
@@ -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:
mm/memory.c
+2 -2
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));