1 files changed, 55 insertions, 3 deletions

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 801fbe1d837..524d23b8610 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -593,6 +593,8 @@ static inline pgste_t pgste_update_all(pte_t *ptep, pgste_t pgste)
 	unsigned long address, bits;
 	unsigned char skey;
 
+	if (!pte_present(*ptep))
+		return pgste;
 	address = pte_val(*ptep) & PAGE_MASK;
 	skey = page_get_storage_key(address);
 	bits = skey & (_PAGE_CHANGED | _PAGE_REFERENCED);
@@ -625,6 +627,8 @@ static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste)
 #ifdef CONFIG_PGSTE
 	int young;
 
+	if (!pte_present(*ptep))
+		return pgste;
 	young = page_reset_referenced(pte_val(*ptep) & PAGE_MASK);
 	/* Transfer page referenced bit to pte software bit (host view) */
 	if (young || (pgste_val(pgste) & RCP_HR_BIT))
@@ -638,13 +642,15 @@ static inline pgste_t pgste_update_young(pte_t *ptep, pgste_t pgste)
 
 }
 
-static inline void pgste_set_pte(pte_t *ptep, pgste_t pgste)
+static inline void pgste_set_pte(pte_t *ptep, pgste_t pgste, pte_t entry)
 {
 #ifdef CONFIG_PGSTE
 	unsigned long address;
 	unsigned long okey, nkey;
 
-	address = pte_val(*ptep) & PAGE_MASK;
+	if (!pte_present(entry))
+		return;
+	address = pte_val(entry) & PAGE_MASK;
 	okey = nkey = page_get_storage_key(address);
 	nkey &= ~(_PAGE_ACC_BITS | _PAGE_FP_BIT);
 	/* Set page access key and fetch protection bit from pgste */
@@ -654,6 +660,52 @@ static inline void pgste_set_pte(pte_t *ptep, pgste_t pgste)
 #endif
 }
 
+/**
+ * struct gmap_struct - guest address space
+ * @mm: pointer to the parent mm_struct
+ * @table: pointer to the page directory
+ * @asce: address space control element for gmap page table
+ * @crst_list: list of all crst tables used in the guest address space
+ */
+struct gmap {
+	struct list_head list;
+	struct mm_struct *mm;
+	unsigned long *table;
+	unsigned long asce;
+	struct list_head crst_list;
+};
+
+/**
+ * struct gmap_rmap - reverse mapping for segment table entries
+ * @next: pointer to the next gmap_rmap structure in the list
+ * @entry: pointer to a segment table entry
+ */
+struct gmap_rmap {
+	struct list_head list;
+	unsigned long *entry;
+};
+
+/**
+ * struct gmap_pgtable - gmap information attached to a page table
+ * @vmaddr: address of the 1MB segment in the process virtual memory
+ * @mapper: list of segment table entries maping a page table
+ */
+struct gmap_pgtable {
+	unsigned long vmaddr;
+	struct list_head mapper;
+};
+
+struct gmap *gmap_alloc(struct mm_struct *mm);
+void gmap_free(struct gmap *gmap);
+void gmap_enable(struct gmap *gmap);
+void gmap_disable(struct gmap *gmap);
+int gmap_map_segment(struct gmap *gmap, unsigned long from,
+		     unsigned long to, unsigned long length);
+int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len);
+unsigned long __gmap_fault(unsigned long address, struct gmap *);
+unsigned long gmap_fault(unsigned long address, struct gmap *);
+void gmap_discard(unsigned long from, unsigned long to, struct gmap *);
+
 /*
  * Certain architectures need to do special things when PTEs
  * within a page table are directly modified.  Thus, the following
@@ -666,7 +718,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 
 	if (mm_has_pgste(mm)) {
 		pgste = pgste_get_lock(ptep);
-		pgste_set_pte(ptep, pgste);
+		pgste_set_pte(ptep, pgste, entry);
 		*ptep = entry;
 		pgste_set_unlock(ptep, pgste);
 	} else