[PATCH v2] mips: Add '-std=gnu11' to vdso CFLAGS
From: Khem Raj
Date: Wed Mar 26 2025 - 23:30:18 EST
GCC 15 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, mips/vdso code uses
its 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.
Signed-off-by: Khem Raj <raj.khem@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
v2: Filter the -std flag from KBUILD_CFLAGS instead of hardcoding
arch/mips/vdso/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index fb4c493aaffa..69d4593f64fe 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -27,6 +27,7 @@ endif
# offsets.
cflags-vdso := $(ccflags-vdso) \
$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \
+ $(filter -std=%,$(KBUILD_CFLAGS)) \
-O3 -g -fPIC -fno-strict-aliasing -fno-common -fno-builtin -G 0 \
-mrelax-pic-calls $(call cc-option, -mexplicit-relocs) \
-fno-stack-protector -fno-jump-tables -DDISABLE_BRANCH_PROFILING \