x86/efi: move the logic to detect PE build support

So that it can be used by the linker script also. With this change the
linker script processor is capable of knowing whether the build has
been performed with PE support or not, and thus create a dummy efi
symbol only when required.

This avoid using a conditional expression with DEFINED on the linker
script, and prevents the following build error with lld (LLVM linker):

ld    -melf_x86_64_fbsd  -T xen.lds -N prelink.o --build-id=sha1 \
    /root/src/xen/xen/common/symbols-dummy.o -o /root/src/xen/xen/.xen-syms.0
ld: error: xen.lds:233: symbol not found: efi

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 5563c813dd71f3b037e14454a33190c95b8fd191..59f96626aa9c7b15029ece7076a242c8e24b0553 100644 (file)
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -168,6 +168,16 @@ $(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A ALT_
 # Don't use $(wildcard ...) here - at least make 3.80 expands this too early!
 $(TARGET).efi: guard = $(if $(shell echo efi/dis* | grep disabled),:)
 
+# Check if the build system supports PE.
+efi := y$(shell rm -f efi/disabled)
+efi := $(if $(efi),$(shell $(CC) $(filter-out $(CFLAGS-y) .%.d,$(CFLAGS)) -c efi/check.c -o efi/check.o 2>efi/disabled && echo y))
+efi := $(if $(efi),$(shell $(LD) -mi386pep --subsystem=10 -o efi/check.efi efi/check.o 2>efi/disabled && echo y))
+efi := $(if $(efi),$(shell rm efi/disabled)y)
+export BUILD_PE := $(efi)
+ifeq ($(efi),y)
+CFLAGS += -DBUILD_PE
+endif
+
 ifneq ($(build_id_linker),)
 ifeq ($(call ld-ver-build-id,$(LD) $(filter -m%,$(EFI_LDFLAGS))),y)
 CFLAGS += -DBUILD_ID_EFI

diff --git a/xen/arch/x86/efi/Makefile b/xen/arch/x86/efi/Makefile
index 3be96611089f35b06078461efccf0f4da225269e..ff5e33fb25dc2e4db4dc1ba0707f39ebfb1c4361 100644 (file)
--- a/xen/arch/x86/efi/Makefile
+++ b/xen/arch/x86/efi/Makefile
@@ -1,16 +1,11 @@
 CFLAGS += -fshort-wchar
 
-efi := y$(shell rm -f disabled)
-efi := $(if $(efi),$(shell $(CC) $(filter-out $(CFLAGS-y) .%.d,$(CFLAGS)) -c check.c 2>disabled && echo y))
-efi := $(if $(efi),$(shell $(LD) -mi386pep --subsystem=10 -o check.efi check.o 2>disabled && echo y))
-efi := $(if $(efi),$(shell rm disabled)y)
-
 %.o: %.ihex
        $(OBJCOPY) -I ihex -O binary $< $@
 
 boot.init.o: buildid.o
 
 obj-y := stub.o
-obj-$(efi) := boot.init.o compat.o relocs-dummy.o runtime.o
-extra-$(efi) += buildid.o
-nocov-$(efi) += stub.o
+obj-$(BUILD_PE) := boot.init.o compat.o relocs-dummy.o runtime.o
+extra-$(BUILD_PE) += buildid.o
+nocov-$(BUILD_PE) += stub.o

diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 326e885402abd9374709ad9367f7e8a8cc7d0f49..f93d5d7e1603154a77fb2318676781934a22e0d3 100644 (file)
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -304,7 +304,9 @@ SECTIONS
   } :text
 #endif
 
-  efi = DEFINED(efi) ? efi : .;
+#ifndef BUILD_PE
+  efi = .;
+#endif
 
   /* Sections to be discarded */
   /DISCARD/ : {