[XEN PATCH v9 01/30] build: set XEN_BUILD_EFI earlier

From: Anthony PERARD <anthony.perard@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: "Anthony PERARD" <anthony.perard@citrix.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Julien Grall" <julien@xen.org>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>
Subject: [XEN PATCH v9 01/30] build: set XEN_BUILD_EFI earlier
Date: Tue, 25 Jan 2022 11:00:34 +0000	[thread overview]
Message-ID: <20220125110103.3527686-2-anthony.perard@citrix.com> (raw)
In-Reply-To: <20220125110103.3527686-1-anthony.perard@citrix.com>

We are going to need the variable XEN_BUILD_EFI earlier.

But a side effect of calculating the value of $(XEN_BUILD_EFI) is to
also to generate "efi/check.o" which is used for further checks.
Thus the whole chain that check for EFI support is moved to
"arch.mk".

Some other changes are made to avoid too much duplication:
    - $(efi-check): Used to avoid repeating "efi/check.*". We don't
      set it to the path to the source as it would be wrong as soon
      as we support out-of-tree build.
    - $(LD_PE_check_cmd): As it is called twice, with an updated
      $(EFI_LDFLAGS).

$(nr-fixups) is renamed to $(efi-nr-fixups) as the former might be
a bit too generic.

In order to avoid exporting MKRELOC, the variable is added to $(MAKE)
command line. The only modification needed is in target "build", the
modification target "$(TARGET)" will be needed with a following patch
"build: avoid re-executing the main Makefile by introducing build.mk".

We can now revert 24b0ce9a5da2, we don't need to override efi-y on
recursion anymore.

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

Notes:
    v9:
    - change $(efi-check) to hold the $(basename ) of check.c, and rename
      the variable from $(efi-check-0).
    - unexport MKRELOC, pass it down via command line instead.
    - remove efi-y override which reverts 24b0ce9a5da2
    
    v8:
    - rename to efi-nr-fixups rather than efi-check-relocs
    - use := when assigning variable in makefile when recursive expansion
      isn't needed.
    - no more check of $(efi-y) value for "CFLAGS-$(XEN_BUILD_EFI) +=
      -DXEN_BUILD_EFI".
    
    v7:
    - Do the whole check for EFI support in arch.mk. So efi/check.o is
      produce there and used there, and produce efi/check.efi and use it there.
      Thus avoid the need to repeat the test done for XEN_BUILD_EFI.

 xen/Makefile          |  4 ++--
 xen/arch/x86/Makefile | 46 ++++++-------------------------------------
 xen/arch/x86/arch.mk  | 42 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 42 deletions(-)

diff --git a/xen/Makefile b/xen/Makefile
index 1e10d9f68080..f3ff03a7170e 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -296,7 +296,7 @@ endif # need-config
 .PHONY: build install uninstall clean distclean MAP
 build install uninstall debug clean distclean MAP::
 ifneq ($(XEN_TARGET_ARCH),x86_32)
-	$(MAKE) -f Rules.mk _$@
+	$(MAKE) -f Rules.mk MKRELOC=$(MKRELOC) _$@
 else
 	echo "*** Xen x86/32 target no longer supported!"
 endif
@@ -404,7 +404,7 @@ $(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) $@
+	$(MAKE) -f $(BASEDIR)/Rules.mk -C arch/$(TARGET_ARCH) MKRELOC=$(MKRELOC) $@
 
 quiet_cmd_banner = BANNER  $@
 define cmd_banner
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 8db4cb98edbb..9fc884813cb5 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -121,44 +121,8 @@ $(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
 		{ echo "No Multiboot2 header found" >&2; false; }
 	mv $(TMP) $(TARGET)
 
-ifneq ($(efi-y),)
-
-# Check if the compiler supports the MS ABI.
-export XEN_BUILD_EFI := $(shell $(CC) $(XEN_CFLAGS) -c efi/check.c -o efi/check.o 2>/dev/null && echo y)
 CFLAGS-$(XEN_BUILD_EFI) += -DXEN_BUILD_EFI
 
-# Check if the linker supports PE.
-EFI_LDFLAGS = $(patsubst -m%,-mi386pep,$(XEN_LDFLAGS)) --subsystem=10
-XEN_BUILD_PE := $(if $(XEN_BUILD_EFI),$(call ld-option,$(EFI_LDFLAGS) --image-base=0x100000000 -o efi/check.efi efi/check.o))
-# If the above failed, it may be merely because of the linker not dealing well
-# with debug info. Try again with stripping it.
-ifeq ($(CONFIG_DEBUG_INFO)-$(XEN_BUILD_PE),y-n)
-EFI_LDFLAGS += --strip-debug
-XEN_BUILD_PE := $(call ld-option,$(EFI_LDFLAGS) --image-base=0x100000000 -o efi/check.efi efi/check.o)
-endif
-
-ifeq ($(XEN_BUILD_PE),y)
-
-# Check if the linker produces fixups in PE by default
-nr-fixups := $(shell $(OBJDUMP) -p efi/check.efi | grep '^[[:blank:]]*reloc[[:blank:]]*[0-9][[:blank:]].*DIR64$$' | wc -l)
-ifeq ($(nr-fixups),2)
-MKRELOC := :
-relocs-dummy :=
-else
-MKRELOC := efi/mkreloc
-relocs-dummy := efi/relocs-dummy.o
-# If the linker produced fixups but not precisely two of them, we need to
-# disable it doing so.  But if it didn't produce any fixups, it also wouldn't
-# recognize the option.
-ifneq ($(nr-fixups),0)
-EFI_LDFLAGS += --disable-reloc-section
-endif
-endif
-
-endif # $(XEN_BUILD_PE)
-
-endif # $(efi-y)
-
 ALL_OBJS := $(BASEDIR)/arch/x86/boot/built_in.o $(BASEDIR)/arch/x86/efi/built_in.o $(ALL_OBJS)
 
 ifeq ($(CONFIG_LTO),y)
@@ -182,13 +146,13 @@ $(TARGET)-syms: prelink.o xen.lds
 	$(NM) -pa --format=sysv $(@D)/.$(@F).0 \
 		| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort \
 		>$(@D)/.$(@F).0.S
-	$(MAKE) -f $(BASEDIR)/Rules.mk efi-y= $(@D)/.$(@F).0.o
+	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
 	$(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(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 efi-y= $(@D)/.$(@F).1.o
+	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
 	$(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
 	    $(@D)/.$(@F).1.o -o $@
 	$(NM) -pa --format=sysv $(@D)/$(@F) \
@@ -217,8 +181,10 @@ endif
 
 $(TARGET).efi: VIRT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A VIRT_START$$,,p')
 ifeq ($(MKRELOC),:)
+relocs-dummy :=
 $(TARGET).efi: ALT_BASE :=
 else
+relocs-dummy := efi/relocs-dummy.o
 $(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A ALT_START$$,,p')
 endif
 
@@ -250,14 +216,14 @@ endif
 	$(MKRELOC) $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(@D)/.$(@F).$(base).0) >$(@D)/.$(@F).0r.S
 	$(NM) -pa --format=sysv $(@D)/.$(@F).$(VIRT_BASE).0 \
 		| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort >$(@D)/.$(@F).0s.S
-	$(MAKE) -f $(BASEDIR)/Rules.mk efi-y= $(@D)/.$(@F).0r.o $(@D)/.$(@F).0s.o
+	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0r.o $(@D)/.$(@F).0s.o
 	$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
 	          $(LD) $(call EFI_LDFLAGS,$(base)) -T efi.lds -N $< \
 	                $(@D)/.$(@F).0r.o $(@D)/.$(@F).0s.o $(note_file_option) -o $(@D)/.$(@F).$(base).1 &&) :
 	$(MKRELOC) $(foreach base,$(VIRT_BASE) $(ALT_BASE),$(@D)/.$(@F).$(base).1) >$(@D)/.$(@F).1r.S
 	$(NM) -pa --format=sysv $(@D)/.$(@F).$(VIRT_BASE).1 \
 		| $(BASEDIR)/tools/symbols $(all_symbols) --sysv --sort >$(@D)/.$(@F).1s.S
-	$(MAKE) -f $(BASEDIR)/Rules.mk efi-y= $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o
+	$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o
 	$(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T efi.lds -N $< \
 	                $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o $(note_file_option) -o $@
 	$(NM) -pa --format=sysv $(@D)/$(@F) \
diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index eea320e618b9..a93fa6d2e4c9 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -60,5 +60,47 @@ ifeq ($(CONFIG_UBSAN),y)
 $(call cc-option-add,CFLAGS_UBSAN,CC,-fno-sanitize=alignment)
 endif
 
+ifneq ($(CONFIG_PV_SHIM_EXCLUSIVE),y)
+
+efi-check := arch/x86/efi/check
+
+# Check if the compiler supports the MS ABI.
+XEN_BUILD_EFI := $(call if-success,$(CC) $(CFLAGS) -c $(efi-check).c -o $(efi-check).o,y)
+
+# Check if the linker supports PE.
+EFI_LDFLAGS := $(patsubst -m%,-mi386pep,$(LDFLAGS)) --subsystem=10
+LD_PE_check_cmd = $(call ld-option,$(EFI_LDFLAGS) --image-base=0x100000000 -o $(efi-check).efi $(efi-check).o)
+XEN_BUILD_PE := $(LD_PE_check_cmd)
+
+# If the above failed, it may be merely because of the linker not dealing well
+# with debug info. Try again with stripping it.
+ifeq ($(CONFIG_DEBUG_INFO)-$(XEN_BUILD_PE),y-n)
+EFI_LDFLAGS += --strip-debug
+XEN_BUILD_PE := $(LD_PE_check_cmd)
+endif
+
+ifeq ($(XEN_BUILD_PE),y)
+
+# Check if the linker produces fixups in PE by default
+efi-nr-fixups := $(shell $(OBJDUMP) -p $(efi-check).efi | grep '^[[:blank:]]*reloc[[:blank:]]*[0-9][[:blank:]].*DIR64$$' | wc -l)
+
+ifeq ($(efi-nr-fixups),2)
+MKRELOC := :
+else
+MKRELOC := efi/mkreloc
+# If the linker produced fixups but not precisely two of them, we need to
+# disable it doing so.  But if it didn't produce any fixups, it also wouldn't
+# recognize the option.
+ifneq ($(efi-nr-fixups),0)
+EFI_LDFLAGS += --disable-reloc-section
+endif
+endif
+
+endif # $(XEN_BUILD_PE)
+
+export XEN_BUILD_EFI XEN_BUILD_PE
+export EFI_LDFLAGS
+endif
+
 # Set up the assembler include path properly for older toolchains.
 CFLAGS += -Wa,-I$(BASEDIR)/include
-- 
Anthony PERARD


