[XEN PATCH v9 04/30] build: set ALL_OBJS in main Makefile; move prelink.o to main Makefile

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

This is to avoid arch/$arch/Makefile having to recurse into parents
directories.

This avoid duplication of the logic to build prelink.o between arches.

In order to do that, we cut the $(TARGET) target in the main Makefile in
two, there is a "prepare" phase/target runned before starting to build
"prelink.o" which will prepare "include/" among other things, then all
the $(ALL_OBJS) will be generated in order to build "prelink.o" and
finally $(TARGET) will be generated by calling into "arch/*/" to make
$(TARGET).

Now we don't need to prefix $(ALL_OBJS) with $(BASEDIR) as it is now
only used from the main Makefile. Other changes is to use "$<" instead
of spelling "prelink.o" in the target "$(TARGET)" in both
arch/*/Makefile.

Beside "prelink.o" been at a different location, no other functional
change intended.

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---

Notes:
    v9:
    - set ALL_OBJS and ALL_LIBS on make command line instead of exporting
      them.
    - arm/Rules.mk, have one rule instead of two for head.o
    - fix typo in title
    
    v8:
    - rebased
    - move Arm specific dependencies between $(ALL_OBJS) objects (head.o)
      into Arm specific "Rules.mk" instead of the common "build.mk".
    
    v7:
    - change, now things are in build.mk: no more prepare phase needed

 xen/Makefile          | 12 +++++++++++-
 xen/Rules.mk          | 13 -------------
 xen/arch/arm/Makefile | 31 ++++---------------------------
 xen/arch/arm/Rules.mk |  4 ++++
 xen/arch/arm/arch.mk  |  2 ++
 xen/arch/x86/Makefile | 29 ++++++-----------------------
 xen/arch/x86/arch.mk  |  2 ++
 xen/build.mk          | 18 ++++++++++++++++++
 8 files changed, 47 insertions(+), 64 deletions(-)

diff --git a/xen/Makefile b/xen/Makefile
index fb37043d08e0..d953dc50ac6a 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -285,6 +285,16 @@ CFLAGS += -flto
 LDFLAGS-$(CONFIG_CC_IS_CLANG) += -plugin LLVMgold.so
 endif
 
+# Note that link order matters!
+ALL_OBJS-y                := common/built_in.o
+ALL_OBJS-y                += drivers/built_in.o
+ALL_OBJS-y                += lib/built_in.o
+ALL_OBJS-y                += xsm/built_in.o
+ALL_OBJS-y                += arch/$(TARGET_ARCH)/built_in.o
+ALL_OBJS-$(CONFIG_CRYPTO) += crypto/built_in.o
+
+ALL_LIBS-y                := lib/lib.a
+
 include $(BASEDIR)/arch/$(TARGET_ARCH)/arch.mk
 
 # define new variables to avoid the ones defined in Config.mk
@@ -407,7 +417,7 @@ $(TARGET): FORCE
        $(MAKE) -f $(BASEDIR)/Rules.mk -C include
        $(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) include
        $(MAKE) -f $(BASEDIR)/Rules.mk 
arch/$(TARGET_ARCH)/include/asm/asm-offsets.h
-       $(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) 
MKRELOC=$(MKRELOC) $@
+       $(MAKE) -f $(BASEDIR)/Rules.mk MKRELOC=$(MKRELOC) 
"ALL_OBJS=$(ALL_OBJS-y)" "ALL_LIBS=$(ALL_LIBS-y)" $@
 
 SUBDIRS = xsm arch/$(TARGET_ARCH) common drivers lib test
 define all_sources
diff --git a/xen/Rules.mk b/xen/Rules.mk
index 7b8b9047cfd5..77d359bedaf8 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -8,25 +8,12 @@
 include $(XEN_ROOT)/Config.mk
 include $(BASEDIR)/scripts/Kbuild.include
 
-# Note that link order matters!
-ALL_OBJS-y               += $(BASEDIR)/common/built_in.o
-ALL_OBJS-y               += $(BASEDIR)/drivers/built_in.o
-ALL_OBJS-y               += $(BASEDIR)/lib/built_in.o
-ALL_OBJS-y               += $(BASEDIR)/xsm/built_in.o
-ALL_OBJS-y               += $(BASEDIR)/arch/$(TARGET_ARCH)/built_in.o
-ALL_OBJS-$(CONFIG_CRYPTO)   += $(BASEDIR)/crypto/built_in.o
-
-ALL_LIBS-y               := $(BASEDIR)/lib/lib.a
-
 # Initialise some variables
 lib-y :=
 targets :=
 CFLAGS-y :=
 AFLAGS-y :=
 
-ALL_OBJS := $(ALL_OBJS-y)
-ALL_LIBS := $(ALL_LIBS-y)
-
 SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, \
                                             $(foreach w,1 2 4, \
                                                         rodata.str$(w).$(a)) \
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index d0dee10102b6..14952275772b 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -75,14 +75,6 @@ ifneq ($(CONFIG_DTB_FILE),"")
 obj-y += dtb.o
 endif
 
-ALL_OBJS := $(TARGET_SUBARCH)/head.o $(ALL_OBJS)
-
-# head.o is built by descending into the sub-directory, depends on the part of
-# $(ALL_OBJS) that will eventually recurse into $(TARGET_SUBARCH)/ and build
-# head.o
-$(TARGET_SUBARCH)/head.o: $(BASEDIR)/arch/arm/built_in.o
-$(TARGET_SUBARCH)/head.o: ;
-
 ifdef CONFIG_LIVEPATCH
 all_symbols = --all-symbols
 ifdef CONFIG_FAST_SYMBOL_LOOKUP
@@ -98,33 +90,18 @@ ifeq ($(CONFIG_ARM_64),y)
        ln -sf $(@F) $@.efi
 endif
 
-ifeq ($(CONFIG_LTO),y)
-# Gather all LTO objects together
-prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS)
-       $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) 
--end-group
-
-# Link it with all the binary objects
-prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o
-       $(call if_changed,ld)
-else
-prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE
-       $(call if_changed,ld)
-endif
-
-targets += prelink.o
-
-$(TARGET)-syms: prelink.o xen.lds
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o \
+$(TARGET)-syms: $(BASEDIR)/prelink.o xen.lds
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< \
            $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
        $(NM) -pa --format=sysv $(@D)/.$(@F).0 \
                | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort 
>$(@D)/.$(@F).0.S
        $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o \
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< \
            $(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
        $(NM) -pa --format=sysv $(@D)/.$(@F).1 \
                | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort 
>$(@D)/.$(@F).1.S
        $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< $(build_id_linker) \
            $(@D)/.$(@F).1.o -o $@
        $(NM) -pa --format=sysv $(@D)/$(@F) \
                | $(BASEDIR)/tools/symbols --all-symbols --xensyms --sysv 
--sort \
diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index e69de29bb2d1..c6463a433efd 100644
--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -0,0 +1,4 @@
+# head.o is built by descending into arch/arm/$(TARGET_SUBARCH), depends on the
+# part of $(ALL_OBJS) that will eventually recurse into $(TARGET_SUBARCH)/ and
+# build head.o
+arch/arm/$(TARGET_SUBARCH)/head.o: arch/arm/built_in.o ;
diff --git a/xen/arch/arm/arch.mk b/xen/arch/arm/arch.mk
index c3ac443b3788..ba3f140e2ea7 100644
--- a/xen/arch/arm/arch.mk
+++ b/xen/arch/arm/arch.mk
@@ -26,3 +26,5 @@ ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
         LDFLAGS += --fix-cortex-a53-843419
     endif
 endif
+
+ALL_OBJS-y := arch/arm/$(TARGET_SUBARCH)/head.o $(ALL_OBJS-y)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 9fc884813cb5..a830b5791e8b 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -123,37 +123,20 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
 
 CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI
 
-ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o 
$(BASEDIR)/arch/x86/efi/built_in.o $(ALL_OBJS)
-
-ifeq ($(CONFIG_LTO),y)
-# Gather all LTO objects together
-prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS)
-       $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) 
--end-group
-
-# Link it with all the binary objects
-prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o 
FORCE
-       $(call if_changed,ld)
-else
-prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE
-       $(call if_changed,ld)
-endif
-
-targets += prelink.o
-
-$(TARGET)-syms: prelink.o xen.lds
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
+$(TARGET)-syms: $(BASEDIR)/prelink.o xen.lds
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< $(build_id_linker) \
            $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
        $(NM) -pa --format=sysv $(@D)/.$(@F).0 \
                | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort \
                >$(@D)/.$(@F).0.S
        $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< $(build_id_linker) \
            $(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
        $(NM) -pa --format=sysv $(@D)/.$(@F).1 \
                | $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort 
$(syms-warn-dup-y) \
                >$(@D)/.$(@F).1.S
        $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
-       $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
+       $(LD) $(XEN_LDFLAGS) -T xen.lds -N $< $(build_id_linker) \
            $(@D)/.$(@F).1.o -o $@
        $(NM) -pa --format=sysv $(@D)/$(@F) \
                | $(BASEDIR)/tools/symbols --all-symbols --xensyms --sysv 
--sort \
@@ -206,7 +189,7 @@ note_file_option ?= $(note_file)
 
 ifeq ($(XEN_BUILD_PE),y)
 extra-y += efi.lds
-$(TARGET).efi: prelink.o $(note_file) efi.lds efi/relocs-dummy.o efi/mkreloc
+$(TARGET).efi: $(BASEDIR)/prelink.o $(note_file) efi.lds efi/relocs-dummy.o 
efi/mkreloc
 ifeq ($(CONFIG_DEBUG_INFO),y)
        $(if $(filter --strip-debug,$(EFI_LDFLAGS)),echo,:) "Will strip debug 
info from $(@F)"
 endif
@@ -235,7 +218,7 @@ $(TARGET).efi: FORCE
        echo '$(if $(filter y,$(XEN_BUILD_EFI)),xen.efi generation,EFI support) 
disabled'
 endif
 
-efi/buildid.o efi/relocs-dummy.o: $(BASEDIR)/arch/x86/efi/built_in.o
+# These should already have been rebuilt when building the prerequisite of 
"prelink.o"
 efi/buildid.o efi/relocs-dummy.o: ;
 
 .PHONY: include
diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index fa7cf3844362..bfd5eaa35f25 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -104,3 +104,5 @@ endif
 
 # Set up the assembler include path properly for older toolchains.
 CFLAGS += -Wa,-I$(BASEDIR)/include
+
+ALL_OBJS-y := arch/x86/boot/built_in.o arch/x86/efi/built_in.o $(ALL_OBJS-y)
diff --git a/xen/build.mk b/xen/build.mk
index 3d7a91df22d1..af1b28311393 100644
--- a/xen/build.mk
+++ b/xen/build.mk
@@ -59,3 +59,21 @@ arch/$(TARGET_ARCH)/include/asm/asm-offsets.h: asm-offsets.s
          sed -rne "/^[^#].*==>/{s:.*==>(.*)<==.*:\1:; s: [\$$#]: :; p;}"; \
          echo ""; \
          echo "#endif") <$< >$@
+
+ifeq ($(CONFIG_LTO),y)
+# Gather all LTO objects together
+prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS)
+       $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) 
--end-group
+
+# Link it with all the binary objects
+prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o 
FORCE
+       $(call if_changed,ld)
+else
+prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE
+       $(call if_changed,ld)
+endif
+
+targets += prelink.o
+
+$(TARGET): prelink.o FORCE
+       $(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) $@
-- 
Anthony PERARD