[S390] System z large page support.
This adds hugetlbfs support on System z, using both hardware large page
support if available and software large page emulation on older hardware.
Shared (large) page tables are implemented in software emulation mode,
by using page->index of the first tail page from a compound large page
to store page table information.
Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/include/asm-s390/pgtable.h b/include/asm-s390/pgtable.h
index f8347ce..fd336f2 100644
--- a/include/asm-s390/pgtable.h
+++ b/include/asm-s390/pgtable.h
@@ -234,6 +234,15 @@
#define _PAGE_TYPE_EX_RW 0x002
/*
+ * Only four types for huge pages, using the invalid bit and protection bit
+ * of a segment table entry.
+ */
+#define _HPAGE_TYPE_EMPTY 0x020 /* _SEGMENT_ENTRY_INV */
+#define _HPAGE_TYPE_NONE 0x220
+#define _HPAGE_TYPE_RO 0x200 /* _SEGMENT_ENTRY_RO */
+#define _HPAGE_TYPE_RW 0x000
+
+/*
* PTE type bits are rather complicated. handle_pte_fault uses pte_present,
* pte_none and pte_file to find out the pte type WITHOUT holding the page
* table lock. ptep_clear_flush on the other hand uses ptep_clear_flush to
@@ -325,6 +334,9 @@
#define _SEGMENT_ENTRY (0)
#define _SEGMENT_ENTRY_EMPTY (_SEGMENT_ENTRY_INV)
+#define _SEGMENT_ENTRY_LARGE 0x400 /* STE-format control, large page */
+#define _SEGMENT_ENTRY_CO 0x100 /* change-recording override */
+
#endif /* __s390x__ */
/*