+ assert_msg(!va_offset(start), "not page aligned");
+ assert_msg(!va_offset(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(!va_offset(start), "not page aligned");
+ assert_msg(!va_offset(length), "not page aligned");
+ struct mm_region* region = valloc(sizeof(struct mm_region));
+ *region = (struct mm_region){ .attr = attr,
+ .start = start,
+ .end = ROUNDUP(start + length, MEM_PAGE) };
+ return region;
+}
+
+struct mm_region*
+region_dup(struct mm_region* origin)
+{
+ struct mm_region* region = valloc(sizeof(struct mm_region));
+ *region = *origin;
+
+ if (region->mfile) {
+ vfs_ref_file(region->mfile);
+ }
+
+ llist_init_head(®ion->head);
+ return region;