Since
commit a9c87304b76d ("build-sys: fix building with make CFLAGS=.. argument")
pc-bios/s390-ccw.img build might fail with
--- snip ---
main.o: In function `virtio_setup':
qemu/pc-bios/s390-ccw/main.c:117: undefined reference to `__stack_chk_fail'
--- snip ---
Changing the CFLAGS to QEMU_CFLAGS does the trick.
We also need to fix a potential aliasing bug as we now compile with
-O2 instead of -O0. This was the warning message:
--- snip ---
/home/cborntra/REPOS/qemu/pc-bios/s390-ccw/virtio.c:64:5: error:
dereferencing type-punned pointer will break strict-aliasing rules
[-Werror=strict-aliasing]
return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
--- snip ---
Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com>
---
pc-bios/s390-ccw/Makefile | 6 ++++--
pc-bios/s390-ccw/virtio.c | 7 ++++++-
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index 4208cb4..a9dcca4 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -10,8 +10,10 @@ $(call set-vpath, $(SRC_PATH)/pc-bios/s390-ccw)
.PHONY : all clean build-all
OBJECTS = start.o main.o bootmap.o sclp-ascii.o virtio.o virtio-scsi.o
-CFLAGS += -fPIE -fno-stack-protector -ffreestanding -march=z900
-CFLAGS += -fno-delete-null-pointer-checks -msoft-float
+QEMU_CFLAGS := $(filter -W%, $(QEMU_CFLAGS))
+QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -msoft-float
+QEMU_CFLAGS += -march=z900 -fPIE
+QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
LDFLAGS += -Wl,-pie -nostdlib
build-all: s390-ccw.img
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 1d34e8c..9a7681d 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -61,7 +61,12 @@ static long kvm_hypercall(unsigned long nr, unsigned long
param1,
static long virtio_notify(SubChannelId schid, int vq_idx, long cookie)
{
- return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid,
+ union {
+ SubChannelId schid;
+ u32 value;
+ } sch;
+ sch.schid = schid;
+ return kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, sch.value,
vq_idx, cookie);
}
--
2.5.5
