From 90c7eee53fcc0b48bd51aa3a7d1d0d9980ce1a7a Mon Sep 17 00:00:00 2001
From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 7 Aug 2020 13:32:11 +0200
Subject: [PATCH] x86/EFI: sanitize build logic

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@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
 xen/arch/x86/Makefile     | 30 ++++++++++++++----------------
 xen/arch/x86/efi/Makefile |  5 +++--
 2 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index b388861679..77e5534cff 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -113,28 +113,35 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
 		{ 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
 
 $(TARGET)-syms: prelink.o xen.lds
@@ -171,12 +178,6 @@ EFI_LDFLAGS += --minor-image-version=$(XEN_SUBVERSION)
 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')
 
@@ -223,9 +224,6 @@ $(TARGET).efi: FORCE
 	echo '$(if $(filter y,$(XEN_BUILD_EFI)),xen.efi generation,EFI support) disabled'
 endif
 
-efi/boot.init.o efi/runtime.o efi/compat.o efi/buildid.o efi/relocs-dummy.o: $(BASEDIR)/arch/x86/efi/built_in.o
-efi/boot.init.o efi/runtime.o efi/compat.o efi/buildid.o efi/relocs-dummy.o: ;
-
 asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c $(BASEDIR)/include/asm-x86/asm-macros.h
 	$(CC) $(filter-out -Wa$(comma)% -flto,$(c_flags)) -S -o $@ $<
 
diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index 3e4c395b75..4b2b010a80 100644
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -14,6 +14,7 @@ $(call cc-option-add,cflags-stack-boundary,CC,-mpreferred-stack-boundary=4)
 $(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
-- 
2.30.2