utcb handling helper routines for the thread library.

This is one of the steps we need in the process of providing a similar interface
for thread creation which can be found in the mainstream operating systems like
Linux.

conts/libl4thread/src/addr.c

@@ -0,0 +1,55 @@
+/*
+ * This module allocates an unused address range from
+ * a given memory region defined as the pool range.
+ *
+ * Copyright (C) 2007 Bahadir Balban
+ */
+#include <addr.h>
+#include <stdio.h>
+
+/*
+ * Initializes an address pool, but uses an already
+ * allocated id pool for it.
+ */
+int address_pool_init_with_idpool(struct address_pool *pool,
+				  struct id_pool *idpool,
+				  unsigned long start, unsigned long end)
+{
+	pool->idpool = idpool;
+	pool->start = start;
+	pool->end = end;
+
+	return 0;
+}
+
+int address_pool_init(struct address_pool *pool, unsigned long start, unsigned long end)
+{
+	if ((pool->idpool = id_pool_new_init(__pfn(end - start))) < 0)
+		return (int)pool->idpool;
+	pool->start = start;
+	pool->end = end;
+	return 0;
+}
+
+void *address_new(struct address_pool *pool, int npages)
+{
+	unsigned int pfn;
+
+	if ((int)(pfn = ids_new_contiguous(pool->idpool, npages)) < 0)
+		return 0;
+
+	return (void *)__pfn_to_addr(pfn) + pool->start;
+}
+
+int address_del(struct address_pool *pool, void *addr, int npages)
+{
+	unsigned long pfn = __pfn(page_align(addr) - pool->start);
+
+	if (ids_del_contiguous(pool->idpool, pfn, npages) < 0) {
+		printf("%s: Invalid address range returned to "
+		       "virtual address pool.\n", __FUNCTION__);
+		return -1;
+	}
+	return 0;
+}
+