basic memory management

src/arch/x86_64/main.c

@@ -22,9 +22,10 @@ void x86_64_main(u32 magic, multiboot_info_t* info)
     }
 
     idt_init();
-
     mem_init(info);
 
+    mem_alloc_2mb(MiB(128) + 1);
+
     remap_pic();
     enable_interrupts();
     kernel_main();