diff --git a/Makefile b/Makefile
index 5de848b..f8cc863 100644
--- a/Makefile
+++ b/Makefile
@@ -32,7 +32,7 @@ OBJS = \
 
 # riscv64-unknown-elf- or riscv64-linux-gnu-
 # perhaps in /opt/riscv/bin
-#TOOLPREFIX = 
+#TOOLPREFIX =
 
 # Try to infer the correct TOOLPREFIX if not set
 ifndef TOOLPREFIX
@@ -73,6 +73,8 @@ endif
 
 LDFLAGS = -z max-page-size=4096
 
+all: kernel world fs
+
 $K/kernel: $(OBJS) $K/kernel.ld $U/initcode
 	$(LD) $(LDFLAGS) -T $K/kernel.ld -o $K/kernel $(OBJS) 
 	$(OBJDUMP) -S $K/kernel > $K/kernel.asm
@@ -139,7 +141,7 @@ fs.img: mkfs/mkfs README.md $(UPROGS)
 
 -include kernel/*.d user/*.d
 
-clean: 
+clean:
 	rm -f *.tex *.dvi *.idx *.aux *.log *.ind *.ilg \
 	*/*.o */*.d */*.asm */*.sym \
 	$U/initcode $U/initcode.out $K/kernel fs.img \