trial implementation of private file mapping

for review only.  will soon be reverted.

kernel/include/pager.h

@@ -0,0 +1,26 @@
+#ifndef HEADER_PAGER_H
+#define HEADER_PAGER_H
+
+#include <ihk/types.h>
+
+enum pager_op {
+	PAGER_REQ_CREATE =	0x0001,
+	PAGER_REQ_RELEASE =	0x0002,
+	PAGER_REQ_READ =	0x0003,
+};
+
+/*
+ * int pager_req_create(int fd, int flags, int prot, uintptr_t result_rpa);
+ */
+struct pager_create_result {
+	uintptr_t	handle;
+	int		maxprot;
+};
+
+/*
+ * int pager_req_release(uintptr_t handle);
+ */
+/*
+ * int pager_req_read(uintptr_t handle, off_t off, size_t size, uintptr_t buf_rpa);
+ */
+#endif /* HEADER_PAGER_H */