[RFC PATCH 08/12] configure: enable cross-compilation of s390-ccw

[Paolo Bonzini <pbonzini@redhat.com>]

While container-based cross compilers are not supported, this already makes
it possible to build s390-ccw on any machine that has s390x GCC and binutils
installed.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configure                    | 18 +++++++++++++-----
 pc-bios/s390-ccw/Makefile    |  9 +++++----
 pc-bios/s390-ccw/netboot.mak |  2 +-
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/configure b/configure
index de2bc799cd..5c34d8ffc2 100755
--- a/configure
+++ b/configure
@@ -2251,24 +2251,32 @@ if { test "$cpu" = "i386" || test "$cpu" = "x86_64"; } && \
     done
 fi
 
-# Only build s390-ccw bios if we're on s390x and the compiler has -march=z900
-# or -march=z10 (which is the lowest architecture level that Clang supports)
-if test "$cpu" = "s390x" ; then
+# Only build s390-ccw bios the compiler has -march=z900 or -march=z10 (which is
+# the lowest architecture level that Clang supports)
+probe_target_compiler s390x
+if test -n "$target_cc" && test "$softmmu" = yes; then
   write_c_skeleton
-  compile_prog "-march=z900" ""
+  do_compiler "$target_cc" $target_cc_cflags -march=z900 -o $TMPO -c $TMPC
   has_z900=$?
-  if [ $has_z900 = 0 ] || compile_object "-march=z10 -msoft-float -Werror"; then
+  if [ $has_z900 = 0 ] || do_compiler "$target_cc" $target_cc_cflags -march=z10 -msoft-float -Werror -o $TMPO -c $TMPC; then
     if [ $has_z900 != 0 ]; then
       echo "WARNING: Your compiler does not support the z900!"
       echo "         The s390-ccw bios will only work with guest CPUs >= z10."
     fi
     roms="$roms s390-ccw"
+    config_mak=pc-bios/s390-ccw/config-host.mak
+    echo "# Automatically generated by configure - do not modify" > $config_mak
+    echo "SRC_PATH=$source_path/pc-bios/s390-ccw" >> $config_mak
+    write_target_makefile >> $config_mak
     # SLOF is required for building the s390-ccw firmware on s390x,
     # since it is using the libnet code from SLOF for network booting.
     git_submodules="${git_submodules} roms/SLOF"
   fi
 fi
 
+#######################################
+# generate config-host.mak
+
 # Check that the C++ compiler exists and works with the C compiler.
 # All the QEMU_CXXFLAGS are based on QEMU_CFLAGS. Keep this at the end to don't miss any other that could be added.
 if has $cxx; then
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index 0eb68efc7b..6eb713bf37 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -2,8 +2,9 @@ all: build-all
 # Dummy command so that make thinks it has done something
 	@true
 
-include ../../config-host.mak
+include config-host.mak
 CFLAGS = -O2 -g
+MAKEFLAGS += -rR
 
 quiet-command = $(if $(V),$1,$(if $(2),@printf "  %-7s %s\n" $2 $3 && $1, @$1))
 cc-option = $(if $(shell $(CC) $1 $2 -S -o /dev/null -xc /dev/null \
@@ -11,7 +12,7 @@ cc-option = $(if $(shell $(CC) $1 $2 -S -o /dev/null -xc /dev/null \
 
 VPATH_SUFFIXES = %.c %.h %.S %.m %.mak %.sh %.rc Kconfig% %.json.in
 set-vpath = $(if $1,$(foreach PATTERN,$(VPATH_SUFFIXES),$(eval vpath $(PATTERN) $1)))
-$(call set-vpath, $(SRC_PATH)/pc-bios/s390-ccw)
+$(call set-vpath, $(SRC_PATH))
 
 # Flags for dependency generation
 QEMU_DGFLAGS = -MMD -MP -MT $@ -MF $(@D)/$(*F).d
@@ -49,8 +50,8 @@ s390-ccw.img: s390-ccw.elf
 
 $(OBJECTS): Makefile
 
-ifneq ($(wildcard $(SRC_PATH)/roms/SLOF/lib/libnet),)
-include $(SRC_PATH)/pc-bios/s390-ccw/netboot.mak
+ifneq ($(wildcard $(SRC_PATH)/../../roms/SLOF/lib/libnet),)
+include $(SRC_PATH)/netboot.mak
 else
 s390-netboot.img:
 	@echo "s390-netboot.img not built since roms/SLOF/ is not available."
diff --git a/pc-bios/s390-ccw/netboot.mak b/pc-bios/s390-ccw/netboot.mak
index 68b4d7edcb..1a06befa4b 100644
--- a/pc-bios/s390-ccw/netboot.mak
+++ b/pc-bios/s390-ccw/netboot.mak
@@ -1,5 +1,5 @@
 
-SLOF_DIR := $(SRC_PATH)/roms/SLOF
+SLOF_DIR := $(SRC_PATH)/../../roms/SLOF
 
 NETOBJS := start.o sclp.o cio.o virtio.o virtio-net.o jump2ipl.o netmain.o
 
-- 
2.35.1