1 files changed, 56 insertions, 0 deletions

diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
new file mode 100644
index 000000000000..de364ecb8df6
--- /dev/null
+++ b/include/asm-generic/pgtable-nop4d.h
@@ -0,0 +1,56 @@
+#ifndef _PGTABLE_NOP4D_H
+#define _PGTABLE_NOP4D_H
+
+#ifndef __ASSEMBLY__
+
+#define __PAGETABLE_P4D_FOLDED
+
+typedef struct { pgd_t pgd; } p4d_t;
+
+#define P4D_SHIFT       PGDIR_SHIFT
+#define PTRS_PER_P4D    1
+#define P4D_SIZE        (1UL << P4D_SHIFT)
+#define P4D_MASK        (~(P4D_SIZE-1))
+
+/*
+ * The "pgd_xxx()" functions here are trivial for a folded two-level
+ * setup: the p4d is never bad, and a p4d always exists (as it's folded
+ * into the pgd entry)
+ */
+static inline int pgd_none(pgd_t pgd)           { return 0; }
+static inline int pgd_bad(pgd_t pgd)            { return 0; }
+static inline int pgd_present(pgd_t pgd)        { return 1; }
+static inline void pgd_clear(pgd_t *pgd)        { }
+#define p4d_ERROR(p4d)                          (pgd_ERROR((p4d).pgd))
+
+#define pgd_populate(mm, pgd, p4d)              do { } while (0)
+/*
+ * (p4ds are folded into pgds so this doesn't get actually called,
+ * but the define is needed for a generic inline function.)
+ */
+#define set_pgd(pgdptr, pgdval) set_p4d((p4d_t *)(pgdptr), (p4d_t) { pgdval })
+
+static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address)
+{
+        return (p4d_t *)pgd;
+}
+
+#define p4d_val(x)                              (pgd_val((x).pgd))
+#define __p4d(x)                                ((p4d_t) { __pgd(x) })
+
+#define pgd_page(pgd)                           (p4d_page((p4d_t){ pgd }))
+#define pgd_page_vaddr(pgd)                     (p4d_page_vaddr((p4d_t){ pgd }))
+
+/*
+ * allocating and freeing a p4d is trivial: the 1-entry p4d is
+ * inside the pgd, so has no extra memory associated with it.
+ */
+#define p4d_alloc_one(mm, address)              NULL
+#define p4d_free(mm, x)                         do { } while (0)
+#define __p4d_free_tlb(tlb, x, a)               do { } while (0)
+
+#undef  p4d_addr_end
+#define p4d_addr_end(addr, end)                 (end)
+
+#endif /* __ASSEMBLY__ */
+#endif /* _PGTABLE_NOP4D_H */