[XEN PATCH v6 05/31] build: factorise generation of the linker scripts

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

In Arm and X86 makefile, generating the linker script is the same, so
we can simply have both call the same macro.

We need to add *.lds files into extra-y so that Rules.mk can find the
.*.cmd dependency file and load it.

Change made to the command line:
- Use cpp_flags macro which simply filter -Wa,% options from $(a_flags).
- Added -D__LINKER__ even it is only used by Arm's lds.

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

Notes:
    v6:
    - CPP already used instead of CC -E
    - -Ui386 already removed
    - cpp_flags is now a macro
    - rebased
    
    v5:
    - rename cc_lds_S to cpp_lds_S as the binary runned is now CPP
    - Use new cpp_flags instead of the open-coded filter of a_flags.
    
    v4:
    - fix rebuild by adding FORCE as dependency
    - Use $(CPP)
    - remove -Ui386
    - avoid using "define" for cmd_cc_lds_S, as adding '; \' on each line is
      still mandatory for if_changed (or cmd) macro to work.

 xen/Rules.mk          | 4 ++++
 xen/arch/arm/Makefile | 6 ++++--
 xen/arch/x86/Makefile | 6 ++++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/xen/Rules.mk b/xen/Rules.mk
index 4adc90eec80d..f05b2d3f0399 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -255,6 +255,10 @@ cmd_cpp_s_S = $(CPP) $(call cpp_flags,$(a_flags)) -MQ $@ 
-o $@ $<
 %.s: %.S FORCE
        $(call if_changed,cpp_s_S)
 
+# Linker scripts, .lds.S -> .lds
+quiet_cmd_cpp_lds_S = LDS     $@
+cmd_cpp_lds_S = $(CPP) -P $(call cpp_flags,$(a_flags)) -D__LINKER__ -MQ $@ -o 
$@ $<
+
 # Add intermediate targets:
 # When building objects with specific suffix patterns, add intermediate
 # targets that the final targets are derived from.
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 3d3b97b5b440..0edd9dee6f49 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -66,6 +66,8 @@ obj-y += vpsci.o
 obj-y += vuart.o
 extra-y += $(TARGET_SUBARCH)/head.o
 
+extra-y += xen.lds
+
 #obj-bin-y += ....o
 
 ifneq ($(CONFIG_DTB_FILE),"")
@@ -133,8 +135,8 @@ $(TARGET)-syms: prelink.o xen.lds
 .PHONY: include
 include:
 
-xen.lds: xen.lds.S
-       $(CPP) -P $(a_flags) -D__LINKER__ -MQ $@ -o $@ $<
+xen.lds: xen.lds.S FORCE
+       $(call if_changed,cpp_lds_S)
 
 dtb.o: $(patsubst "%",%,$(CONFIG_DTB_FILE))
 
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 2ec883456e48..08a4ec1944d3 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -79,6 +79,7 @@ obj-y += sysctl.o
 endif
 
 extra-y += asm-macros.i
+extra-y += xen.lds
 
 ifneq ($(CONFIG_HVM),y)
 x86_emulate.o: CFLAGS-y += -Wno-unused-label
@@ -240,6 +241,7 @@ endif
 note_file_option ?= $(note_file)
 
 ifeq ($(XEN_BUILD_PE),y)
+extra-y += efi.lds
 $(TARGET).efi: prelink.o $(note_file) efi.lds efi/relocs-dummy.o efi/mkreloc
 ifeq ($(CONFIG_DEBUG_INFO),y)
        $(if $(filter --strip-debug,$(EFI_LDFLAGS)),echo,:) "Will strip debug 
info from $(@F)"
@@ -292,8 +294,8 @@ $(BASEDIR)/include/asm-x86/asm-macros.h: asm-macros.i 
Makefile
        $(call move-if-changed,$@.new,$@)
 
 efi.lds: AFLAGS-y += -DEFI
-xen.lds efi.lds: xen.lds.S
-       $(CPP) -P $(filter-out -Wa$(comma)%,$(a_flags)) -MQ $@ -o $@ $<
+xen.lds efi.lds: xen.lds.S FORCE
+       $(call if_changed,cpp_lds_S)
 
 boot/mkelf32: boot/mkelf32.c
        $(HOSTCC) $(HOSTCFLAGS) -o $@ $<
-- 
Anthony PERARD