v4.19.13 snapshot.
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
new file mode 100644
index 0000000..2d1afa5
--- /dev/null
+++ b/arch/s390/include/asm/hugetlb.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * IBM System z Huge TLB Page Support for Kernel.
+ *
+ * Copyright IBM Corp. 2008
+ * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#ifndef _ASM_S390_HUGETLB_H
+#define _ASM_S390_HUGETLB_H
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+
+#define is_hugepage_only_range(mm, addr, len) 0
+#define hugetlb_free_pgd_range free_pgd_range
+#define hugepages_supported() (MACHINE_HAS_EDAT1)
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte);
+pte_t huge_ptep_get(pte_t *ptep);
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+
+/*
+ * If the arch doesn't supply something else, assume that hugepage
+ * size aligned regions are ok without further preparation.
+ */
+static inline int prepare_hugepage_range(struct file *file,
+ unsigned long addr, unsigned long len)
+{
+ if (len & ~HPAGE_MASK)
+ return -EINVAL;
+ if (addr & ~HPAGE_MASK)
+ return -EINVAL;
+ return 0;
+}
+
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+ clear_bit(PG_arch_1, &page->flags);
+}
+
+static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, unsigned long sz)
+{
+ if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+ pte_val(*ptep) = _REGION3_ENTRY_EMPTY;
+ else
+ pte_val(*ptep) = _SEGMENT_ENTRY_EMPTY;
+}
+
+static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ huge_ptep_get_and_clear(vma->vm_mm, address, ptep);
+}
+
+static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t pte, int dirty)
+{
+ int changed = !pte_same(huge_ptep_get(ptep), pte);
+ if (changed) {
+ huge_ptep_get_and_clear(vma->vm_mm, addr, ptep);
+ set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+ }
+ return changed;
+}
+
+static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ pte_t pte = huge_ptep_get_and_clear(mm, addr, ptep);
+ set_huge_pte_at(mm, addr, ptep, pte_wrprotect(pte));
+}
+
+static inline pte_t mk_huge_pte(struct page *page, pgprot_t pgprot)
+{
+ return mk_pte(page, pgprot);
+}
+
+static inline int huge_pte_none(pte_t pte)
+{
+ return pte_none(pte);
+}
+
+static inline int huge_pte_write(pte_t pte)
+{
+ return pte_write(pte);
+}
+
+static inline int huge_pte_dirty(pte_t pte)
+{
+ return pte_dirty(pte);
+}
+
+static inline pte_t huge_pte_mkwrite(pte_t pte)
+{
+ return pte_mkwrite(pte);
+}
+
+static inline pte_t huge_pte_mkdirty(pte_t pte)
+{
+ return pte_mkdirty(pte);
+}
+
+static inline pte_t huge_pte_wrprotect(pte_t pte)
+{
+ return pte_wrprotect(pte);
+}
+
+static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
+{
+ return pte_modify(pte, newprot);
+}
+
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void) { return true; }
+#endif
+#endif /* _ASM_S390_HUGETLB_H */