File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
new file mode 100644
index 0000000..5991cdc
--- /dev/null
+++ b/arch/s390/include/asm/pgalloc.h
@@ -0,0 +1,146 @@
+/*
+ *  S390 version
+ *    Copyright IBM Corp. 1999, 2000
+ *    Author(s): Hartmut Penner (hp@de.ibm.com)
+ *               Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *
+ *  Derived from "include/asm-i386/pgalloc.h"
+ *    Copyright (C) 1994  Linus Torvalds
+ */
+
+#ifndef _S390_PGALLOC_H
+#define _S390_PGALLOC_H
+
+#include <linux/threads.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+
+unsigned long *crst_table_alloc(struct mm_struct *);
+void crst_table_free(struct mm_struct *, unsigned long *);
+
+unsigned long *page_table_alloc(struct mm_struct *);
+void page_table_free(struct mm_struct *, unsigned long *);
+void page_table_free_rcu(struct mmu_gather *, unsigned long *, unsigned long);
+extern int page_table_allocate_pgste;
+
+int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
+			  unsigned long key, bool nq);
+unsigned long get_guest_storage_key(struct mm_struct *mm, unsigned long addr);
+
+static inline void clear_table(unsigned long *s, unsigned long val, size_t n)
+{
+	typedef struct { char _[n]; } addrtype;
+
+	*s = val;
+	n = (n / 256) - 1;
+	asm volatile(
+		"	mvc	8(248,%0),0(%0)\n"
+		"0:	mvc	256(256,%0),0(%0)\n"
+		"	la	%0,256(%0)\n"
+		"	brct	%1,0b\n"
+		: "+a" (s), "+d" (n), "=m" (*(addrtype *) s)
+		: "m" (*(addrtype *) s));
+}
+
+static inline void crst_table_init(unsigned long *crst, unsigned long entry)
+{
+	clear_table(crst, entry, sizeof(unsigned long)*2048);
+}
+
+static inline unsigned long pgd_entry_type(struct mm_struct *mm)
+{
+	if (mm->context.asce_limit <= (1UL << 31))
+		return _SEGMENT_ENTRY_EMPTY;
+	if (mm->context.asce_limit <= (1UL << 42))
+		return _REGION3_ENTRY_EMPTY;
+	return _REGION2_ENTRY_EMPTY;
+}
+
+int crst_table_upgrade(struct mm_struct *);
+void crst_table_downgrade(struct mm_struct *);
+
+static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+	unsigned long *table = crst_table_alloc(mm);
+	if (table)
+		crst_table_init(table, _REGION3_ENTRY_EMPTY);
+	return (pud_t *) table;
+}
+#define pud_free(mm, pud) crst_table_free(mm, (unsigned long *) pud)
+
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
+{
+	unsigned long *table = crst_table_alloc(mm);
+
+	if (!table)
+		return NULL;
+	crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
+	if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
+		crst_table_free(mm, table);
+		return NULL;
+	}
+	return (pmd_t *) table;
+}
+
+static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
+{
+	pgtable_pmd_page_dtor(virt_to_page(pmd));
+	crst_table_free(mm, (unsigned long *) pmd);
+}
+
+static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
+{
+	pgd_val(*pgd) = _REGION2_ENTRY | __pa(pud);
+}
+
+static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
+{
+	pud_val(*pud) = _REGION3_ENTRY | __pa(pmd);
+}
+
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	unsigned long *table = crst_table_alloc(mm);
+
+	if (!table)
+		return NULL;
+	if (mm->context.asce_limit == (1UL << 31)) {
+		/* Forking a compat process with 2 page table levels */
+		if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
+			crst_table_free(mm, table);
+			return NULL;
+		}
+	}
+	return (pgd_t *) table;
+}
+
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+	if (mm->context.asce_limit == (1UL << 31))
+		pgtable_pmd_page_dtor(virt_to_page(pgd));
+	crst_table_free(mm, (unsigned long *) pgd);
+}
+
+static inline void pmd_populate(struct mm_struct *mm,
+				pmd_t *pmd, pgtable_t pte)
+{
+	pmd_val(*pmd) = _SEGMENT_ENTRY + __pa(pte);
+}
+
+#define pmd_populate_kernel(mm, pmd, pte) pmd_populate(mm, pmd, pte)
+
+#define pmd_pgtable(pmd) \
+	(pgtable_t)(pmd_val(pmd) & -sizeof(pte_t)*PTRS_PER_PTE)
+
+/*
+ * page table entry allocation/free routines.
+ */
+#define pte_alloc_one_kernel(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
+#define pte_alloc_one(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
+
+#define pte_free_kernel(mm, pte) page_table_free(mm, (unsigned long *) pte)
+#define pte_free(mm, pte) page_table_free(mm, (unsigned long *) pte)
+
+extern void rcu_table_freelist_finish(void);
+
+#endif /* _S390_PGALLOC_H */