[PATCH] pc-bios/s390-ccw: Generate and include dependency files in the Makefile

[PATCH] pc-bios/s390-ccw: Generate and include dependency files in the Makefile

[Thomas Huth]

The Makefile of the s390-ccw bios does not handle dependencies of the
*.c files from the headers yet, so that you often have to run a "make
clean" to get the build right when one of the headers has been changed.
Let's make sure that we generate and include dependency files for all
*.c files now to avoid this problem in the future.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 pc-bios/s390-ccw/Makefile    |  3 +++
 pc-bios/s390-ccw/netboot.mak | 13 +++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index a048b6b077..50bc880272 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -38,5 +38,8 @@ s390-netboot.img:
 	@echo "s390-netboot.img not built since roms/SLOF/ is not available."
 endif
 
+ALL_OBJS = $(sort $(OBJECTS) $(NETOBJS) $(LIBCOBJS) $(LIBNETOBJS))
+-include $(ALL_OBJS:%.o=%.d)
+
 clean:
 	rm -f *.o *.d *.img *.elf *~ *.a
diff --git a/pc-bios/s390-ccw/netboot.mak b/pc-bios/s390-ccw/netboot.mak
index 5eefb7c289..577c023afe 100644
--- a/pc-bios/s390-ccw/netboot.mak
+++ b/pc-bios/s390-ccw/netboot.mak
@@ -1,8 +1,7 @@
 
 SLOF_DIR := $(SRC_PATH)/roms/SLOF
 
-NETOBJS := start.o sclp.o cio.o virtio.o virtio-net.o jump2ipl.o netmain.o \
-	   libnet.a libc.a
+NETOBJS := start.o sclp.o cio.o virtio.o virtio-net.o jump2ipl.o netmain.o
 
 LIBC_INC := -nostdinc -I$(SLOF_DIR)/lib/libc/include
 LIBNET_INC := -I$(SLOF_DIR)/lib/libnet
@@ -11,15 +10,16 @@ NETLDFLAGS := $(LDFLAGS) -Ttext=0x7800000
 
 $(NETOBJS): QEMU_CFLAGS += $(LIBC_INC) $(LIBNET_INC)
 
-s390-netboot.elf: $(NETOBJS)
-	$(call quiet-command,$(CC) $(NETLDFLAGS) -o $@ $(NETOBJS),"BUILD","$(TARGET_DIR)$@")
+s390-netboot.elf: $(NETOBJS) libnet.a libc.a
+	$(call quiet-command,$(CC) $(NETLDFLAGS) -o $@ $^,"BUILD","$(TARGET_DIR)$@")
 
 s390-netboot.img: s390-netboot.elf
 	$(call quiet-command,$(STRIP) --strip-unneeded $< -o $@,"STRIP","$(TARGET_DIR)$@")
 
 # libc files:
 
-LIBC_CFLAGS :=  $(QEMU_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC)
+LIBC_CFLAGS = $(QEMU_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
+	      -MMD -MP -MT $@ -MF $(@:%.o=%.d)
 
 CTYPE_OBJS = isdigit.o isxdigit.o toupper.o
 %.o : $(SLOF_DIR)/lib/libc/ctype/%.c
@@ -52,7 +52,8 @@ libc.a: $(LIBCOBJS)
 
 LIBNETOBJS := args.o dhcp.o dns.o icmpv6.o ipv6.o tcp.o udp.o bootp.o \
 	      dhcpv6.o ethernet.o ipv4.o ndp.o tftp.o pxelinux.o
-LIBNETCFLAGS := $(QEMU_CFLAGS) $(CFLAGS) -DDHCPARCH=0x1F $(LIBC_INC) $(LIBNET_INC)
+LIBNETCFLAGS = $(QEMU_CFLAGS) $(CFLAGS) $(LIBC_INC) $(LIBNET_INC) \
+	       -DDHCPARCH=0x1F -MMD -MP -MT $@ -MF $(@:%.o=%.d)
 
 %.o : $(SLOF_DIR)/lib/libnet/%.c
 	$(call quiet-command,$(CC) $(LIBNETCFLAGS) -c -o $@ $<,"CC","$(TARGET_DIR)$@")
-- 
2.18.1

Re: [PATCH] pc-bios/s390-ccw: Generate and include dependency files in the Makefile

[Cornelia Huck]

On Tue, 30 Jun 2020 16:29:55 +0200
Thomas Huth <thuth@redhat.com> wrote:

> The Makefile of the s390-ccw bios does not handle dependencies of the
> *.c files from the headers yet, so that you often have to run a "make
> clean" to get the build right when one of the headers has been changed.
> Let's make sure that we generate and include dependency files for all
> *.c files now to avoid this problem in the future.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  pc-bios/s390-ccw/Makefile    |  3 +++
>  pc-bios/s390-ccw/netboot.mak | 13 +++++++------
>  2 files changed, 10 insertions(+), 6 deletions(-)

My Makefile-fu is not that strong, but this looks sane to me.

Acked-by: Cornelia Huck <cohuck@redhat.com>

[I can also pick this directly, if you do not plan to send me a bios
pull req.]