* [Qemu-devel] [PATCH] s390/bios: build with -fdelete-null-pointer-checks
@ 2015-06-15 10:24 Aurelien Jarno
2015-06-15 10:54 ` Christian Borntraeger
0 siblings, 1 reply; 2+ messages in thread
From: Aurelien Jarno @ 2015-06-15 10:24 UTC (permalink / raw)
To: qemu-devel
Cc: Cornelia Huck, Christian Borntraeger, Alexander Graf,
Aurelien Jarno
Starting with version 4.9, GCC assumes it can't safely dereference null
pointers, and uses this for some optimizations. On s390, the lowcore
memory is located at address 0, so this assumption is wrong and breaks
the s390-ccw firmware. Pass -fdelete-null-pointer-checks to avoid that.
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
pc-bios/s390-ccw/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index 009bb8d..746603a 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -10,7 +10,7 @@ $(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
-CFLAGS += -fPIE -fno-stack-protector -ffreestanding
+CFLAGS += -fPIE -fno-stack-protector -ffreestanding -fno-delete-null-pointer-checks
LDFLAGS += -Wl,-pie -nostdlib
build-all: s390-ccw.img
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH] s390/bios: build with -fdelete-null-pointer-checks
2015-06-15 10:24 [Qemu-devel] [PATCH] s390/bios: build with -fdelete-null-pointer-checks Aurelien Jarno
@ 2015-06-15 10:54 ` Christian Borntraeger
0 siblings, 0 replies; 2+ messages in thread
From: Christian Borntraeger @ 2015-06-15 10:54 UTC (permalink / raw)
To: Aurelien Jarno, qemu-devel; +Cc: Cornelia Huck, Alexander Graf
Am 15.06.2015 um 12:24 schrieb Aurelien Jarno:
> Starting with version 4.9, GCC assumes it can't safely dereference null
> pointers, and uses this for some optimizations. On s390, the lowcore
> memory is located at address 0, so this assumption is wrong and breaks
> the s390-ccw firmware. Pass -fdelete-null-pointer-checks to avoid that.
>
> Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: Alexander Graf <agraf@suse.de>
> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
> ---
> pc-bios/s390-ccw/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
> index 009bb8d..746603a 100644
> --- a/pc-bios/s390-ccw/Makefile
> +++ b/pc-bios/s390-ccw/Makefile
> @@ -10,7 +10,7 @@ $(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
> -CFLAGS += -fPIE -fno-stack-protector -ffreestanding
> +CFLAGS += -fPIE -fno-stack-protector -ffreestanding -fno-delete-null-pointer-checks
> LDFLAGS += -Wl,-pie -nostdlib
>
> build-all: s390-ccw.img
>
applied thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-06-15 10:54 ` Christian Borntraeger
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