From 1344794a59db2bd44b4919d2d75300fd3b1c2cd7 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 8 Mar 2022 22:56:12 +0100 Subject: Kbuild: add -Wno-shift-negative-value where -Wextra is used As a preparation for moving to -std=gnu11, turn off the -Wshift-negative-value option. This warning is enabled by gcc when building with -Wextra for c99 or higher, but not for c89. Since the kernel already relies on well-defined overflow behavior, the warning is not helpful and can simply be disabled in all locations that use -Wextra. Signed-off-by: Arnd Bergmann Acked-by: Jani Nikula Reviewed-by: Nathan Chancellor Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) Signed-off-by: Masahiro Yamada --- scripts/Makefile.extrawarn | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 8be892887d71..650d0b8ceec3 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -36,6 +36,7 @@ KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation) KBUILD_CFLAGS += -Wno-missing-field-initializers KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-type-limits +KBUILD_CFLAGS += -Wno-shift-negative-value KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 -- cgit v1.2.3-59-g8ed1b From 4d94f910e79a349b00a4f8aab6f3ae87129d8c5a Mon Sep 17 00:00:00 2001 From: Mark Rutland 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 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 [arnd: don't add a duplicate flag to the default set, update changelog] Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Tested-by: Sedat Dilek # LLVM/Clang v13.0.0 (x86-64) Signed-off-by: Masahiro Yamada --- Makefile | 3 ++- arch/arm64/kernel/vdso32/Makefile | 1 + scripts/mod/modpost.c | 4 +++- 3 files changed, 6 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/Makefile b/Makefile index 51e142f760f7..84a2de340934 100644 --- a/Makefile +++ b/Makefile @@ -432,7 +432,8 @@ 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) diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 6c01b63ff56d..f46457f1f4f0 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -68,6 +68,7 @@ VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -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 diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 6bfa33217914..fe693304b120 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -833,8 +833,10 @@ static int match(const char *sym, const char * const pat[]) { 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 == '*') { -- cgit v1.2.3-59-g8ed1b