diff --git a/src/early_kernel.c b/src/early_kernel.c
index febf8ca..43d728b 100644
--- a/src/early_kernel.c
+++ b/src/early_kernel.c
@@ -3,6 +3,7 @@
 #include <paging.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <serial.h>
 
 void early_kernel_main() {
   serial_init();
diff --git a/src/include/serial.h b/src/include/serial.h
index d3326e8..717aa35 100644
--- a/src/include/serial.h
+++ b/src/include/serial.h
@@ -9,5 +9,8 @@ int serial_init();
 int dbg_putchar(int c);
 int vdbgf(const char *restrict format, va_list ap);
 int dbgf(const char *restrict format, ...);
+int warn(const char *restrict format, ...);
+int error(const char *restrict format, ...);
+int fixme(const char *restrict format, ...);
 
 #endif
diff --git a/src/kernel.c b/src/kernel.c
index 46d3c21..4ede7ba 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -6,4 +6,7 @@
 void kernel_main() {
   kprintf("Hello, World!\n");
   dbgf("Hello serial World!\n");
+  warn("test warning debug %d\n", 42);
+  error("test error debug %d\n", 42);
+  fixme("test fixme debug %d\n", 42);
 }
diff --git a/src/serial.c b/src/serial.c
index ea6c425..80b3901 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -53,3 +53,33 @@ int dbgf(const char *restrict format, ...) {
   va_end(ap);
   return size;
 }
+
+int warn(const char *restrict format, ...) {
+  int size;
+  va_list ap;
+  va_start(ap, format);
+  dbgf("WARNING: ");
+  size = vdbgf(format, ap);
+  va_end(ap);
+  return size;
+}
+
+int error(const char *restrict format, ...) {
+  int size;
+  va_list ap;
+  va_start(ap, format);
+  dbgf("ERROR: ");
+  size = vdbgf(format, ap);
+  va_end(ap);
+  return size;
+}
+
+int fixme(const char *restrict format, ...) {
+  int size;
+  va_list ap;
+  va_start(ap, format);
+  dbgf("FIXME: ");
+  size = vdbgf(format, ap);
+  va_end(ap);
+  return size;
+}