qemu/pc-bios/s390-ccw/Makefile
Thomas Huth 63c93fac18 pc-bios/s390-ccw: Optimize the s390-netboot.img for size
The -O2 optimization flag is passed via CFLAGS to the firmware Makefile,
but in netbook.mak, we've got some rules that only use QEMU_CFLAGS for
compiling the libc and libnet from SLOF, so these files get compiled
without optimization so far. Use CFLAGS here, too, to create faster
and smaller code.

We can additionally save some more bytes in the firmware images by compi-
ling the code with -fno-asynchronous-unwind-tables. This will omit some
ELF sections (used for stack unwinding for example) from the image that
we do not need in the firmware.

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2018-06-18 15:08:44 +02:00

43 lines
1.2 KiB
Makefile

all: build-all
# Dummy command so that make thinks it has done something
@true
include ../../config-host.mak
include $(SRC_PATH)/rules.mak
$(call set-vpath, $(SRC_PATH)/pc-bios/s390-ccw)
.PHONY : all clean build-all
OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o \
virtio.o virtio-scsi.o virtio-blkdev.o libc.o
QEMU_CFLAGS := $(filter -W%, $(QEMU_CFLAGS))
QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -msoft-float
QEMU_CFLAGS += -march=z900 -fPIE -fno-strict-aliasing
QEMU_CFLAGS += -fno-asynchronous-unwind-tables
QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
LDFLAGS += -Wl,-pie -nostdlib
build-all: s390-ccw.img s390-netboot.img
s390-ccw.elf: $(OBJECTS)
$(call quiet-command,$(CC) $(LDFLAGS) -o $@ $(OBJECTS),"BUILD","$(TARGET_DIR)$@")
STRIP ?= strip
s390-ccw.img: s390-ccw.elf
$(call quiet-command,$(STRIP) --strip-unneeded $< -o $@,"STRIP","$(TARGET_DIR)$@")
$(OBJECTS): Makefile
ifneq ($(wildcard $(SRC_PATH)/roms/SLOF/lib/libnet),)
include $(SRC_PATH)/pc-bios/s390-ccw/netboot.mak
else
s390-netboot.img:
@echo "s390-netboot.img not built since roms/SLOF/ is not available."
endif
clean:
rm -f *.o *.d *.img *.elf *~ *.a