From: Mark Rutland <mark.rutland@arm.com>
Date: Tue, 8 Mar 2022 22:56:13 +0100
Subject: Kbuild: use -Wdeclaration-after-statement
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 4d94f910e79a349b00a4f8aab6f3ae87129d8c5a
Patch-mainline: 5.18-rc1
References: bsc#1204877
The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting
the use of additional C11 features such as for-loop initial declarations.
One contentious aspect of C99 is that it permits mixed declarations and
code, and for now at least, it seems preferable to enforce that
declarations must come first.
These warnings were already enabled in the kernel itself, but not
for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses
a separate set of CFLAGS.
This patch fixes an existing violation in modpost.c, which is not
reported because of the missing flag in KBUILD_USERCFLAGS:
| scripts/mod/modpost.c: In function ‘match’:
| scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
| 837 | const char *endp = p + strlen(p) - 1;
| | ^~~~~
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[arnd: don't add a duplicate flag to the default set, update changelog]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 (x86-64)
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
Makefile | 3 ++-
arch/arm64/kernel/vdso32/Makefile | 1 +
scripts/mod/modpost.c | 4 +++-
3 files changed, 6 insertions(+), 2 deletions(-)
--- a/Makefile
+++ b/Makefile
@@ -433,7 +433,8 @@ HOSTCXX = g++
endif
export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
- -O2 -fomit-frame-pointer -std=gnu89
+ -O2 -fomit-frame-pointer -std=gnu89 \
+ -Wdeclaration-after-statement
export KBUILD_USERLDFLAGS :=
KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-pr
-fno-strict-aliasing -fno-common \
-Werror-implicit-function-declaration \
-Wno-format-security \
+ -Wdeclaration-after-statement \
-std=gnu89
VDSO_CFLAGS += -O2
# Some useful compiler-dependent flags from top-level Makefile
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -824,8 +824,10 @@ static int match(const char *sym, const
{
const char *p;
while (*pat) {
+ const char *endp;
+
p = *pat++;
- const char *endp = p + strlen(p) - 1;
+ endp = p + strlen(p) - 1;
/* "*foo*" */
if (*p == '*' && *endp == '*') {