xen/build: start using if_changed

This patch start to use if_changed introduced in a previous commit.

Whenever if_changed is called, the target must have FORCE as
dependency so that if_changed can check if the command line to be
run has changed, so the macro $(real-prereqs) must be used to
discover the dependencies without "FORCE".

Whenever a target isn't in obj-y, it should be added to extra-y so the
.*.cmd dependency file associated with the target can be loaded. This
is done for xsm/flask/ and both common/lib{elf,fdt}/ and
arch/x86/Makefile.

For the targets that generate .*.d dependency files, there's going to
be two dependency files (.*.d and .*.cmd) until we can merge them
together in a later patch via fixdep from Linux.

One cleanup, libelf-relocate.o doesn't exist anymore.

We import cmd_ld and cmd_objcopy from Linux v5.4.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>

xen/Rules.mk

@@ -56,6 +56,18 @@ SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, \
 
 include Makefile
 
+# Linking
+# ---------------------------------------------------------------------------
+
+quiet_cmd_ld = LD      $@
+cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs)
+
+# Objcopy
+# ---------------------------------------------------------------------------
+
+quiet_cmd_objcopy = OBJCOPY $@
+cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $< $@
+
 define gendep
     ifneq ($(1),$(subst /,:,$(1)))
         DEPS += $(dir $(1)).$(notdir $(1)).d
@@ -164,29 +176,47 @@ else
 	$(CC) $(c_flags) -c $< -o $@
 endif
 
-%.o: %.S Makefile
-	$(CC) $(a_flags) -c $< -o $@
+quiet_cmd_cc_o_S = CC      $@
+cmd_cc_o_S = $(CC) $(a_flags) -c $< -o $@
 
-$(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): %.init.o: %.o Makefile
-	$(OBJDUMP) -h $< | sed -n '/[0-9]/{s,00*,0,g;p;}' | while read idx name sz rest; do \
-		case "$$name" in \
-		.*.local) ;; \
-		.text|.text.*|.data|.data.*|.bss) \
-			test $$sz != 0 || continue; \
-			echo "Error: size of $<:$$name is 0x$$sz" >&2; \
-			exit $$(expr $$idx + 1);; \
-		esac; \
-	done
-	$(OBJCOPY) $(foreach s,$(SPECIAL_DATA_SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@
+%.o: %.S FORCE
+	$(call if_changed,cc_o_S)
 
-%.i: %.c Makefile
-	$(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@
 
-%.s: %.c Makefile
-	$(CC) $(filter-out -Wa$(comma)%,$(c_flags)) -S $< -o $@
+quiet_cmd_obj_init_o = INIT_O  $@
+define cmd_obj_init_o
+    $(OBJDUMP) -h $< | sed -n '/[0-9]/{s,00*,0,g;p;}' | while read idx name sz rest; do \
+        case "$$name" in \
+        .*.local) ;; \
+        .text|.text.*|.data|.data.*|.bss) \
+            test $$sz != 0 || continue; \
+            echo "Error: size of $<:$$name is 0x$$sz" >&2; \
+            exit $$(expr $$idx + 1);; \
+        esac; \
+    done; \
+    $(OBJCOPY) $(foreach s,$(SPECIAL_DATA_SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@
+endef
 
-%.s: %.S Makefile
-	$(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) $< -o $@
+$(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): %.init.o: %.o FORCE
+	$(call if_changed,obj_init_o)
+
+quiet_cmd_cpp_i_c = CPP     $@
+cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@
+
+quiet_cmd_cc_s_c = CC      $@
+cmd_cc_s_c = $(CC) $(filter-out -Wa$(comma)%,$(c_flags)) -S $< -o $@
+
+quiet_cmd_s_S = CPP     $@
+cmd_s_S = $(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) $< -o $@
+
+%.i: %.c FORCE
+	$(call if_changed,cpp_i_c)
+
+%.s: %.c FORCE
+	$(call if_changed,cc_s_c)
+
+%.s: %.S FORCE
+	$(call if_changed,cpp_s_S)
 
 # Add intermediate targets:
 # When building objects with specific suffix patterns, add intermediate

xen/arch/arm/Makefile

@@ -97,8 +97,8 @@ prelink_lto.o: $(ALL_OBJS)
 prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o
 	$(LD) $(XEN_LDFLAGS) -r -o $@ $^
 else
-prelink.o: $(ALL_OBJS)
-	$(LD) $(XEN_LDFLAGS) -r -o $@ $^
+prelink.o: $(ALL_OBJS) FORCE
+	$(call if_changed,ld)
 endif
 
 $(TARGET)-syms: prelink.o xen.lds

xen/arch/x86/Makefile

@@ -71,6 +71,7 @@ obj-$(CONFIG_TBOOT) += tboot.o
 obj-y += hpet.o
 obj-y += vm_event.o
 obj-y += xstate.o
+extra-y += asm-macros.i
 
 x86_emulate.o: x86_emulate/x86_emulate.c x86_emulate/x86_emulate.h
 

xen/arch/x86/efi/Makefile

@@ -1,7 +1,10 @@
 CFLAGS-y += -fshort-wchar
 
-%.o: %.ihex
-	$(OBJCOPY) -I ihex -O binary $< $@
+quiet_cmd_objcopy_o_ihex = OBJCOPY $@
+cmd_objcopy_o_ihex = $(OBJCOPY) -I ihex -O binary $< $@
+
+%.o: %.ihex FORCE
+	$(call if_changed,objcopy_o_ihex)
 
 boot.init.o: buildid.o
 

xen/common/libelf/Makefile

@@ -1,12 +1,16 @@
 obj-bin-y := libelf.o
 nocov-y += libelf.o
+libelf-objs := libelf-tools.o libelf-loader.o libelf-dominfo.o
 
 SECTIONS := text data $(SPECIAL_DATA_SECTIONS)
+OBJCOPYFLAGS := $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s))
 
 CFLAGS-y += -Wno-pointer-sign
 
-libelf.o: libelf-temp.o Makefile
-	$(OBJCOPY) $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@
+libelf.o: libelf-temp.o FORCE
+	$(call if_changed,objcopy)
 
-libelf-temp.o: libelf-tools.o libelf-loader.o libelf-dominfo.o #libelf-relocate.o
-	$(LD) $(XEN_LDFLAGS) -r -o $@ $^
+libelf-temp.o: $(libelf-objs) FORCE
+	$(call if_changed,ld)
+
+extra-y += libelf-temp.o $(libelf-objs)

xen/common/libfdt/Makefile

@@ -1,14 +1,17 @@
 include Makefile.libfdt
 
 SECTIONS := text data $(SPECIAL_DATA_SECTIONS)
+OBJCOPYFLAGS := $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s))
 
 obj-y += libfdt.o
 nocov-y += libfdt.o
 
 CFLAGS-y += -I$(BASEDIR)/include/xen/libfdt/
 
-libfdt.o: libfdt-temp.o Makefile
-	$(OBJCOPY) $(foreach s,$(SECTIONS),--rename-section .$(s)=.init.$(s)) $< $@
+libfdt.o: libfdt-temp.o FORCE
+	$(call if_changed,objcopy)
 
-libfdt-temp.o: $(LIBFDT_OBJS)
-	$(LD) $(XEN_LDFLAGS) -r -o $@ $^
+libfdt-temp.o: $(LIBFDT_OBJS) FORCE
+	$(call if_changed,ld)
+
+extra-y += libfdt-temp.o $(LIBFDT_OBJS)

xen/xsm/flask/Makefile

@@ -20,12 +20,21 @@ AV_H_FILES = include/av_perm_to_string.h include/av_permissions.h
 ALL_H_FILES = $(FLASK_H_FILES) $(AV_H_FILES)
 
 $(obj-y) ss/built_in.o: $(ALL_H_FILES)
+extra-y += $(ALL_H_FILES)
 
-$(subst include/,%/,$(FLASK_H_FILES)): $(FLASK_H_DEPEND)
-	$(CONFIG_SHELL) policy/mkflask.sh $(AWK) include $(FLASK_H_DEPEND)
+mkflask := policy/mkflask.sh
+quiet_cmd_mkflask = MKFLASK $@
+cmd_mkflask = $(CONFIG_SHELL) $(mkflask) $(AWK) include $(FLASK_H_DEPEND)
 
-$(subst include/,%/,$(AV_H_FILES)): $(AV_H_DEPEND)
-	$(CONFIG_SHELL) policy/mkaccess_vector.sh $(AWK) $(AV_H_DEPEND)
+$(subst include/,%/,$(FLASK_H_FILES)): $(FLASK_H_DEPEND) $(mkflask) FORCE
+	$(call if_changed,mkflask)
+
+mkaccess := policy/mkaccess_vector.sh
+quiet_cmd_mkaccess = MKACCESS VECTOR $@
+cmd_mkaccess = $(CONFIG_SHELL) $(mkaccess) $(AWK) $(AV_H_DEPEND)
+
+$(subst include/,%/,$(AV_H_FILES)): $(AV_H_DEPEND) $(mkaccess) FORCE
+	$(call if_changed,mkaccess)
 
 obj-bin-$(CONFIG_XSM_FLASK_POLICY) += flask-policy.o
 flask-policy.o: policy.bin