6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nathan Chancellor <nathan@xxxxxxxxxx>
commit 3b8b80e993766dc96d1a1c01c62f5d15fafc79b9 upstream.
GCC changed the default C standard dialect from gnu17 to gnu23,
which should not have impacted the kernel because it explicitly requests
the gnu11 standard in the main Makefile. However, there are certain
places in the s390 code that use their own CFLAGS without a '-std='
value, which break with this dialect change because of the kernel's own
definitions of bool, false, and true conflicting with the C23 reserved
keywords.
include/linux/stddef.h:11:9: error: cannot use keyword 'false' as enumeration constant
11 | false = 0,
| ^~~~~
include/linux/stddef.h:11:9: note: 'false' is a keyword with '-std=c23' onwards
include/linux/types.h:35:33: error: 'bool' cannot be defined via 'typedef'
35 | typedef _Bool bool;
| ^~~~
include/linux/types.h:35:33: note: 'bool' is a keyword with '-std=c23' onwards
Add '-std=gnu11' to the decompressor and purgatory CFLAGS to eliminate
these errors and make the C standard version of these areas match the
rest of the kernel.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250122-s390-fix-std-for-gcc-15-v1-1-8b00cadee083@xxxxxxxxxx
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/Makefile | 2 +-
arch/s390/purgatory/Makefile | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -21,7 +21,7 @@ KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FL
ifndef CONFIG_AS_IS_LLVM
KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf))
endif
-KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack
+KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack -std=gnu11
KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY
KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain
KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -21,7 +21,7 @@ UBSAN_SANITIZE := n
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes
+KBUILD_CFLAGS := -std=gnu11 -fno-strict-aliasing -Wall -Wstrict-prototypes
KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare
KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding
KBUILD_CFLAGS += -Os -m64 -msoft-float -fno-common
