+struct mm_region*
+region_create(ptr_t start, ptr_t end, u32_t attr)
+{
+ assert_msg(PG_ALIGNED(start), "not page aligned");
+ assert_msg(PG_ALIGNED(end), "not page aligned");
+ struct mm_region* region = valloc(sizeof(struct mm_region));
+ *region =
+ (struct mm_region){ .attr = attr, .start = start, .end = end - 1 };
+ return region;
+}
+
+struct mm_region*
+region_create_range(ptr_t start, size_t length, u32_t attr)
+{
+ assert_msg(PG_ALIGNED(start), "not page aligned");
+ assert_msg(PG_ALIGNED(length), "not page aligned");
+ struct mm_region* region = valloc(sizeof(struct mm_region));
+ *region = (struct mm_region){ .attr = attr,
+ .start = start,
+ .end = PG_ALIGN(start + length - 1) };
+ return region;
+}
+
+void
+region_add(vm_regions_t* lead, struct mm_region* vmregion)
+{
+ if (llist_empty(lead)) {
+ llist_append(lead, &vmregion->head);
+ return;
+ }
+
+ ptr_t cur_end = 0;
+ struct mm_region *pos = (struct mm_region*)lead,
+ *n = list_entry(lead->next, struct mm_region, head);
+ do {
+ if (vmregion->start > cur_end && vmregion->end < n->start) {
+ break;
+ }
+ cur_end = n->end;
+ pos = n;
+ n = list_entry(n->head.next, struct mm_region, head);
+ } while ((ptr_t)&n->head != (ptr_t)lead);
+
+ // XXX caution. require mm_region::head to be the lead of struct
+ llist_insert_after(&pos->head, &vmregion->head);
+}