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 diff --git a/Makefile b/Makefile
  39 index b9e0b5c604af..cfe400032f96 100644
  40 --- a/Makefile
  41 +++ b/Makefile
  42 @@ -416,7 +416,8 @@ HOSTCXX     = g++
  43  endif
  44
  45  export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
  46 -                             -O2 -fomit-frame-pointer -std=gnu89
  47 +                             -O2 -fomit-frame-pointer -std=gnu89 \
  48 +                             -Wdeclaration-after-statement
  49  export KBUILD_USERLDFLAGS :=
  50
  51  KBUILD_HOSTCFLAGS   := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
  52 diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
  53 index abad38c576e1..33cd7ed3f94f 100644
  54 --- a/arch/arm64/kernel/vdso32/Makefile
  55 +++ b/arch/arm64/kernel/vdso32/Makefile
  56 @@ -76,6 +76,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
  57                 -fno-strict-aliasing -fno-common \
  58                 -Werror-implicit-function-declaration \
  59                 -Wno-format-security \
  60 +               -Wdeclaration-after-statement \
  61                 -std=gnu89
  62  VDSO_CFLAGS  += -O2
  63  # Some useful compiler-dependent flags from top-level Makefile
  64 diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
  65 index 3c27a177b28b..d2b17ed27e6e 100644
  66 --- a/scripts/mod/modpost.c
  67 +++ b/scripts/mod/modpost.c
  68 @@ -844,8 +844,10 @@ static int match(const char *sym, const char * const pat[])
  69  {
  70         const char *p;
  71         while (*pat) {
  72 +               const char *endp;
  73 +
  74                 p = *pat++;
  75 -               const char *endp = p + strlen(p) - 1;
  76 +               endp = p + strlen(p) - 1;
  77
  78                 /* "*foo*" */
  79                 if (*p == '*' && *endp == '*') {
  80 --
  81 2.37.2