[PATCH 1/8] x86/EFI: sanitize build logic

[Jan Beulich <jbeulich@xxxxxxxx>]

With changes done over time and as far as linking goes, the only special
thing about building with EFI support enabled is the need for the dummy
relocations object for xen.gz uniformly in all build stages. All other
efi/*.o can be consumed from the built_in*.o files.

In efi/Makefile, besides moving relocs-dummy.o to "extra", also properly
split between obj-y and obj-bin-y.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -113,28 +113,35 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/
                { echo "No Multiboot2 header found" >&2; false; }
        mv $(TMP) $(TARGET)
 
+# Check if the compiler supports the MS ABI.
+export XEN_BUILD_EFI := $(shell $(CC) $(XEN_CFLAGS) -c efi/check.c -o 
efi/check.o 2>/dev/null && echo y)
+# Check if the linker supports PE.
+XEN_BUILD_PE := $(if $(XEN_BUILD_EFI),$(shell $(LD) -mi386pep --subsystem=10 
-o efi/check.efi efi/check.o 2>/dev/null && echo y))
+CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI
+
 ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o 
$(BASEDIR)/arch/x86/efi/built_in.o $(ALL_OBJS)
+EFI_OBJS-$(XEN_BUILD_EFI) := efi/relocs-dummy.o
 
 ifeq ($(CONFIG_LTO),y)
 # Gather all LTO objects together
 prelink_lto.o: $(ALL_OBJS)
        $(LD_LTO) -r -o $@ $^
 
-prelink-efi_lto.o: $(ALL_OBJS) efi/runtime.o efi/compat.o
-       $(LD_LTO) -r -o $@ $(filter-out %/efi/built_in.o,$^)
+prelink-efi_lto.o: $(ALL_OBJS)
+       $(LD_LTO) -r -o $@ $^
 
 # Link it with all the binary objects
-prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o
+prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o 
$(EFI_OBJS-y)
        $(LD) $(XEN_LDFLAGS) -r -o $@ $^
 
-prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink-efi_lto.o efi/boot.init.o
+prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink-efi_lto.o
        $(LD) $(XEN_LDFLAGS) -r -o $@ $^
 else
-prelink.o: $(ALL_OBJS)
+prelink.o: $(ALL_OBJS) $(EFI_OBJS-y)
        $(LD) $(XEN_LDFLAGS) -r -o $@ $^
 
-prelink-efi.o: $(ALL_OBJS) efi/boot.init.o efi/runtime.o efi/compat.o
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %/efi/built_in.o,$^)
+prelink-efi.o: $(ALL_OBJS)
+       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
 endif
 
 $(TARGET)-syms: prelink.o xen.lds
@@ -171,12 +178,6 @@ EFI_LDFLAGS += --minor-image-version=$(X
 EFI_LDFLAGS += --major-os-version=2 --minor-os-version=0
 EFI_LDFLAGS += --major-subsystem-version=2 --minor-subsystem-version=0
 
-# Check if the compiler supports the MS ABI.
-export XEN_BUILD_EFI := $(shell $(CC) $(XEN_CFLAGS) -c efi/check.c -o 
efi/check.o 2>/dev/null && echo y)
-# Check if the linker supports PE.
-XEN_BUILD_PE := $(if $(XEN_BUILD_EFI),$(shell $(LD) -mi386pep --subsystem=10 
-o efi/check.efi efi/check.o 2>/dev/null && echo y))
-CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI
-
 $(TARGET).efi: VIRT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A 
VIRT_START$$,,p')
 $(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A 
ALT_START$$,,p')
 
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -14,6 +14,7 @@ $(call cc-option-add,cflags-stack-bounda
 $(EFIOBJ): CFLAGS-stack-boundary := $(cflags-stack-boundary)
 
 obj-y := stub.o
-obj-$(XEN_BUILD_EFI) := $(EFIOBJ) relocs-dummy.o
-extra-$(XEN_BUILD_EFI) += buildid.o
+obj-$(XEN_BUILD_EFI) := $(filter-out %.init.o,$(EFIOBJ))
+obj-bin-$(XEN_BUILD_EFI) := $(filter %.init.o,$(EFIOBJ))
+extra-$(XEN_BUILD_EFI) += buildid.o relocs-dummy.o
 nocov-$(XEN_BUILD_EFI) += stub.o