Build system simplification/standardisation

This change makes kexec-tools work more like a standard configure-make-
make-install-type project:

* Remove $(OBJDIR) stuff. To do an out-of-tree build, just configure
from a different directory.

* Use the implicit Makefile rules more, and just edit the compiler
flags for specific targets.

* Simplify compiler/linker flags - no need for EXTRA_*

* Add TARGET_CC, and improve checks for BUILD_CC too.

* Set arch-specific flags in arch-specific makefiles, not conditional
on $(ARCH).

* Generate dependency files in the main compile, rather than as a
separate step.

* Don't #include sha256.c, but re-build it into the purgatory.

Still a work-in-progress.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 19 insertions, 51 deletions

diff --git a/kexec/Makefile b/kexec/Makefile
index 6ad9461..6f7a49c 100644
--- a/kexec/Makefile
+++ b/kexec/Makefile
@@ -1,80 +1,48 @@
 #
 # kexec (linux booting linux)
 #
-PURGATORY_HEX_C:= $(OBJDIR)/kexec/purgatory.c
+PURGATORY_HEX_C:= kexec/purgatory.c
 
 $(PURGATORY_HEX_C): $(PURGATORY) $(BIN_TO_HEX)
 	$(MKDIR) -p $(@D)
 	$(BIN_TO_HEX) purgatory < $(PURGATORY) > $@
 
-KCFLAGS:= $(CFLAGS) $(EXTRA_CFLAGS) -Ikexec/arch/$(ARCH)/include
-
-KEXEC_C_SRCS:= kexec/kexec.c 
+KEXEC_C_SRCS:= kexec/kexec.c
 KEXEC_C_SRCS+= kexec/ifdown.c
-KEXEC_C_SRCS+= kexec/kexec-elf.c 
-KEXEC_C_SRCS+= kexec/kexec-elf-exec.c 
+KEXEC_C_SRCS+= kexec/kexec-elf.c
+KEXEC_C_SRCS+= kexec/kexec-elf-exec.c
 KEXEC_C_SRCS+= kexec/kexec-elf-core.c
-KEXEC_C_SRCS+= kexec/kexec-elf-rel.c 
-KEXEC_C_SRCS+= kexec/kexec-elf-boot.c 
+KEXEC_C_SRCS+= kexec/kexec-elf-rel.c
+KEXEC_C_SRCS+= kexec/kexec-elf-boot.c
 KEXEC_C_SRCS+= kexec/kexec-iomem.c
 KEXEC_C_SRCS+= kexec/crashdump.c
 KEXEC_C_SRCS+= kexec/crashdump-xen.c
 KEXEC_C_GENERATED_SRCS+= $(PURGATORY_HEX_C)
-KEXEC_S_SRCS:= 
+KEXEC_S_SRCS:=
 KEXEC_S_GENERATED_SRCS:=
-include kexec/arch/$(ARCH)/Makefile
 
-KEXEC_C_OBJS:= $(patsubst %.c, $(OBJDIR)/%.o, $(KEXEC_C_SRCS) \
-	       $(KEXEC_C_GENERATED_SRCS))
-KEXEC_C_DEPS:= $(patsubst %.c, $(OBJDIR)/%.d, $(KEXEC_C_SRCS))
-KEXEC_C_DUMMY_DEPS:= $(patsubst %.c, $(OBJDIR)/%.d, $(KEXEC_C_GENERATED_SRCS))
-KEXEC_S_OBJS:= $(patsubst %.S, $(OBJDIR)/%.o, $(KEXEC_S_SRCS) \
-	       $(KEXEC_S_GENERATED_SRCS))
-KEXEC_S_DEPS:= $(patsubst %.S, $(OBJDIR)/%.d, $(KEXEC_S_SRCS))
-KEXEC_S_DUMMY_DEPS:= $(patsubst %.c, $(OBJDIR)/%.d, $(KEXEC_S_GENERATED_SRCS))
+include $(srcdir)/kexec/arch/$(ARCH)/Makefile
+
+KEXEC_C_OBJS:= $(patsubst %.c, %.o, $(KEXEC_C_SRCS) $(KEXEC_C_GENERATED_SRCS))
+KEXEC_C_DEPS:= $(patsubst %.c, %.d, $(KEXEC_C_SRCS))
+KEXEC_S_OBJS:= $(patsubst %.S, %.o, $(KEXEC_S_SRCS) $(KEXEC_S_GENERATED_SRCS))
+KEXEC_S_DEPS:= $(patsubst %.S, %.d, $(KEXEC_S_SRCS))
 KEXEC_SRCS:= $(KEXEC_C_SRCS) $(KEXEC_S_SRCS)
 KEXEC_OBJS:= $(KEXEC_C_OBJS) $(KEXEC_S_OBJS)
 KEXEC_DEPS:= $(KEXEC_C_DEPS) $(KEXEC_S_DEPS)
 KEXEC:= $(SBINDIR)/kexec
 KEXEC_MANPAGE:= $(MANDIR)/man8/kexec.8
 
-include $(KEXEC_DEPS)
-
-$(KEXEC_C_DEPS): $(OBJDIR)/%.d: %.c
-	mkdir -p $(@D)
-	$(CC) $(KCFLAGS) -M $< | sed -e 's|$(patsubst %.d,%.o,$(@F))|$(patsubst %.d,%.o,$(@))|' > $@
-
-$(KEXEC_S_DEPS): $(OBJDIR)/%.d: %.S
-	mkdir -p $(@D)
-	$(CC) $(KCFLAGS) -M $< | sed -e 's|$(patsubst %.d,%.o,$(@F))|$(patsubst %.d,%.o,$(@))|' > $@
-
-# This is needed to ensure that the rule below that depend
-# on each .c file having a .d file don't break
-$(KEXEC_C_DUMMY_DEPS): $(OBJDIR)/%.d: %.c
-	mkdir -p $(@D)
-	touch $@
-
-# This is needed to ensure that the rule below that depend
-# on each .S file having a .d file don't break
-$(KEXEC_S_DUMMY_DEPS): $(OBJDIR)/%.d: %.S
-	mkdir -p $(@D)
-	touch $@
-
-$(KEXEC_C_OBJS): $(OBJDIR)/%.o: %.c $(OBJDIR)/%.d
-	mkdir -p $(@D)
-	$(CC) $(KCFLAGS) -o $@ -c $<
-
-$(KEXEC_S_OBJS): $(OBJDIR)/%.o: %.S $(OBJDIR)/%.d
-	mkdir -p $(@D)
-	$(CC) $(KCFLAGS) -o $@ -c $<
+-include $(KEXEC_DEPS)
 
 $(KEXEC): $(KEXEC_OBJS) $(UTIL_LIB)
-	mkdir -p $(@D)
-	$(CC) $(LDFLAGS) $(EXTRA_LDFLAGS) $(KCFLAGS) -o $@ \
-		$(KEXEC_OBJS) $(UTIL_LIB) $(LIBS)
+	@$(MKDIR) -p $(@D)
+	$(LINK.o) -o $@ $^
+
+$(KEXEC): CPPFLAGS+=-I$(srcdir)/kexec/arch/$(ARCH)/include
 
 $(KEXEC_MANPAGE): kexec/kexec.8
-	 $(MKDIR) -p     $(MANDIR)/man8
+	@$(MKDIR) -p     $(MANDIR)/man8
 	cp kexec/kexec.8 $(KEXEC_MANPAGE)
 echo::
 	@echo "KEXEC_C_SRCS $(KEXEC_C_SRCS)"