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[PATCH 3/4] pc-bios/s390-ccw: Silence GCC 11 stringop-overflow warning
From: |
Thomas Huth |
Subject: |
[PATCH 3/4] pc-bios/s390-ccw: Silence GCC 11 stringop-overflow warning |
Date: |
Sun, 2 May 2021 19:48:35 +0200 |
From: Philippe Mathieu-Daudé <philmd@redhat.com>
When building on Fedora 34 (gcc version 11.0.0 20210210) we get:
In file included from pc-bios/s390-ccw/main.c:11:
In function ‘memset’,
inlined from ‘boot_setup’ at pc-bios/s390-ccw/main.c:185:5,
inlined from ‘main’ at pc-bios/s390-ccw/main.c:288:5:
pc-bios/s390-ccw/libc.h:28:14: warning: writing 1 byte into a region of size
0 [-Wstringop-overflow=]
28 | p[i] = c;
| ~~~~~^~~
The offending code is:
memset((char *)S390EP, 0, 6);
where S390EP is a const address:
#define S390EP 0x10008
The compiler doesn't now how big that pointed area is, so assume its
length is zero. This has been reported as BZ#99578 to GCC:
"gcc-11 -Warray-bounds or -Wstringop-overread warning when accessing a
pointer from integer literal"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
As this warning does us more harm than good in the BIOS code (where
lot of direct accesses to low memory are done), silence this warning
for all BIOS objects.
Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210422145911.2513980-1-philmd@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
[thuth: Use the pre-existing cc-option macro instead of adding a new one]
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
pc-bios/s390-ccw/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
index f0fe84c9eb..83fb1afb73 100644
--- a/pc-bios/s390-ccw/Makefile
+++ b/pc-bios/s390-ccw/Makefile
@@ -30,6 +30,7 @@ OBJECTS = start.o main.o bootmap.o jump2ipl.o sclp.o menu.o \
virtio.o virtio-scsi.o virtio-blkdev.o libc.o cio.o dasd-ipl.o
QEMU_CFLAGS := -Wall $(filter -W%, $(QEMU_CFLAGS))
+QEMU_CFLAGS += $(call cc-option,-Werror $(QEMU_CFLAGS),-Wno-stringop-overflow)
QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -fno-common -fPIE
QEMU_CFLAGS += -fwrapv -fno-strict-aliasing -fno-asynchronous-unwind-tables
QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
--
2.27.0
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, (continued)
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Thomas Huth, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, David Hildenbrand, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Markus Armbruster, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Cornelia Huck, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, David Hildenbrand, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Cornelia Huck, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Thomas Huth, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Cornelia Huck, 2021/05/03
- Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Christian Borntraeger, 2021/05/03
Re: [PATCH 4/4] pc-bios/s390-ccw: Allow building with Clang, too, Cornelia Huck, 2021/05/03
[PATCH 3/4] pc-bios/s390-ccw: Silence GCC 11 stringop-overflow warning,
Thomas Huth <=