target/linux/generic/backport-5.15/005-v5.17-01-Kbuild-use-Wdeclaration-after-statement.patch

   1 From 2fd7e7f9317d3048a14026816d081b08ba98ea8e Mon Sep 17 00:00:00 2001
   2 From: Mark Rutland <mark.rutland@arm.com>
   3 Date: Tue, 8 Mar 2022 22:56:13 +0100
   4 Subject: [PATCH 1/3] Kbuild: use -Wdeclaration-after-statement
   5
   6 The kernel is moving from using `-std=gnu89` to `-std=gnu11`, permitting
   7 the use of additional C11 features such as for-loop initial declarations.
   8
   9 One contentious aspect of C99 is that it permits mixed declarations and
  10 code, and for now at least, it seems preferable to enforce that
  11 declarations must come first.
  12
  13 These warnings were already enabled in the kernel itself, but not
  14 for KBUILD_USERCFLAGS or the compat VDSO on arch/arm64, which uses
  15 a separate set of CFLAGS.
  16
  17 This patch fixes an existing violation in modpost.c, which is not
  18 reported because of the missing flag in KBUILD_USERCFLAGS:
  19
  20 | scripts/mod/modpost.c: In function ‘match’:
  21 | scripts/mod/modpost.c:837:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
  22 |   837 |   const char *endp = p + strlen(p) - 1;
  23 |       |   ^~~~~
  24
  25 Signed-off-by: Mark Rutland <mark.rutland@arm.com>
  26 [arnd: don't add a duplicate flag to the default set, update changelog]
  27 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
  28 Reviewed-by: Nathan Chancellor <nathan@kernel.org>
  29 Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
  30 Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 (x86-64)
  31 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
  32 ---
  33  Makefile                          | 3 ++-
  34  arch/arm64/kernel/vdso32/Makefile | 1 +
  35  scripts/mod/modpost.c             | 4 +++-
  36  3 files changed, 6 insertions(+), 2 deletions(-)
  37
  38 --- a/Makefile
  39 +++ b/Makefile
  40 @@ -440,7 +440,8 @@ endif
  41  HOSTPKG_CONFIG = pkg-config
  42
  43  export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
  44 -                             -O2 -fomit-frame-pointer -std=gnu89
  45 +                             -O2 -fomit-frame-pointer -std=gnu89 \
  46 +                             -Wdeclaration-after-statement
  47  export KBUILD_USERLDFLAGS :=
  48
  49  KBUILD_HOSTCFLAGS   := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
  50 --- a/arch/arm64/kernel/vdso32/Makefile
  51 +++ b/arch/arm64/kernel/vdso32/Makefile
  52 @@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-pr
  53                 -fno-strict-aliasing -fno-common \
  54                 -Werror-implicit-function-declaration \
  55                 -Wno-format-security \
  56 +               -Wdeclaration-after-statement \
  57                 -std=gnu89
  58  VDSO_CFLAGS  += -O2
  59  # Some useful compiler-dependent flags from top-level Makefile
  60 --- a/scripts/mod/modpost.c
  61 +++ b/scripts/mod/modpost.c
  62 @@ -833,8 +833,10 @@ static int match(const char *sym, const
  63  {
  64         const char *p;
  65         while (*pat) {
  66 +               const char *endp;
  67 +
  68                 p = *pat++;
  69 -               const char *endp = p + strlen(p) - 1;
  70 +               endp = p + strlen(p) - 1;
  71
  72                 /* "*foo*" */
  73                 if (*p == '*' && *endp == '*') {