s390: Add '-std=gnu11' to decompressor and purgatory CFLAGS

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@vger.kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250122-s390-fix-std-for-gcc-15-v1-1-8b00cadee083@kernel.org
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 3f25498dac656428b9d8c8a1c542dcb07bc7c82e..5fae311203c269f5e0062d267955e1cff4cc6f87 100644 (file)
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -22,7 +22,7 @@ KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__
 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 += -D__DECOMPRESSOR
 KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain

diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile
index 24eccaa293371b0dc693f8b6d854f0c8ff70708c..bdcf2a3b6c41b30432c6952531f3e31e8087f466 100644 (file)
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -13,7 +13,7 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
 $(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE
        $(call if_changed_rule,as_o_S)
 
-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