mm, x86: add support for PUD-sized transparent hugepages

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / mm / pgtable.c

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 3feec5af4e67c096b9bd663edc4a94fb587f67bb..6cbdff26bb96a25939a0e818d4895b42b1a5a130 100644 (file)
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -445,6 +445,26 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
 
        return changed;
 }
+
+int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
+                         pud_t *pudp, pud_t entry, int dirty)
+{
+       int changed = !pud_same(*pudp, entry);
+
+       VM_BUG_ON(address & ~HPAGE_PUD_MASK);
+
+       if (changed && dirty) {
+               *pudp = entry;
+               /*
+                * We had a write-protection fault here and changed the pud
+                * to to more permissive. No need to flush the TLB for that,
+                * #PF is architecturally guaranteed to do that and in the
+                * worst-case we'll generate a spurious fault.
+                */
+       }
+
+       return changed;
+}
 #endif
 
 int ptep_test_and_clear_young(struct vm_area_struct *vma,
@@ -474,6 +494,17 @@ int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 
        return ret;
 }
+int pudp_test_and_clear_young(struct vm_area_struct *vma,
+                             unsigned long addr, pud_t *pudp)
+{
+       int ret = 0;
+
+       if (pud_young(*pudp))
+               ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
+                                        (unsigned long *)pudp);
+
+       return ret;
+}
 #endif
 
 int ptep_clear_flush_young(struct vm_area_struct *vma,