powerpc/mm/hugetlb: Add flush_hugetlb_tlb_range

Some archs like ppc64 need to do special things when flushing tlb for
hugepage. Add a new helper to flush hugetlb tlb range. This helps us to
avoid flushing the entire tlb mapping for the pid.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 9 insertions, 1 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f904246a8fd5..af2d88253bfc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3938,6 +3938,14 @@ same_page:
         return i ? i : -EFAULT;
 }
 
+#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
+/*
+ * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
+ * implement this.
+ */
+#define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
+#endif
+
 unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
                 unsigned long address, unsigned long end, pgprot_t newprot)
 {
@@ -3998,7 +4006,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
          * once we release i_mmap_rwsem, another task can do the final put_page
          * and that page table be reused and filled with junk.
          */
-        flush_tlb_range(vma, start, end);
+        flush_hugetlb_tlb_range(vma, start, end);
         mmu_notifier_invalidate_range(mm, start, end);
         i_mmap_unlock_write(vma->vm_file->f_mapping);
         mmu_notifier_invalidate_range_end(mm, start, end);