| Message ID | 1492150646-20848-1-git-send-email-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Arnd, 2017-04-14 15:17 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>: > Arnd Bergmann reported: > "When ftrace is enabled and we build with gcc-4.7 or older, we > get a warning for each file on architectures that select > CONFIG_LD_DEAD_CODE_DATA_ELIMINATION: > > warning: -ffunction-sections disabled; it makes profiling impossible [enabled by default] > " > > Since commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to > cc-option to support clang"), warnings are treated as errors in > cc-option checks. CC_FLAGS_FTRACE is blindly added to KBUILD_CFLAGS, > so $(call cc-option,-ffunction-sections,) should be moved below it > in order to detect the conflict between the two options. > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > Makefile | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/Makefile b/Makefile > index efa267a..753e450 100644 > --- a/Makefile > +++ b/Makefile > @@ -632,11 +632,6 @@ include arch/$(SRCARCH)/Makefile > KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) > KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) > > -ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION > -KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) > -KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) > -endif > - > ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) > else > @@ -773,6 +768,11 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH > KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) > endif > > +ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION > +KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) > +KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) > +endif > + > # arch Makefile may override CC so keep this after arch Makefile is included > NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) > CHECKFLAGS += $(NOSTDINC_FLAGS) I tested this patch, and confirmed it fixed the issue. So, I will apply this shortly. I used the following GCC 4.7 for testing: https://releases.linaro.org/archive/13.04/components/toolchain/binaries/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux.tar.xz
2017-04-14 15:17 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>: > Arnd Bergmann reported: > "When ftrace is enabled and we build with gcc-4.7 or older, we > get a warning for each file on architectures that select > CONFIG_LD_DEAD_CODE_DATA_ELIMINATION: > > warning: -ffunction-sections disabled; it makes profiling impossible [enabled by default] > " > > Since commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to > cc-option to support clang"), warnings are treated as errors in > cc-option checks. CC_FLAGS_FTRACE is blindly added to KBUILD_CFLAGS, > so $(call cc-option,-ffunction-sections,) should be moved below it > in order to detect the conflict between the two options. > > Reported-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Applied to linux-kbuild/kbuild.
diff --git a/Makefile b/Makefile index efa267a..753e450 100644 --- a/Makefile +++ b/Makefile @@ -632,11 +632,6 @@ include arch/$(SRCARCH)/Makefile KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) -ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION -KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) -KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) -endif - ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else @@ -773,6 +768,11 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) endif +ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION +KBUILD_CFLAGS += $(call cc-option,-ffunction-sections,) +KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) +endif + # arch Makefile may override CC so keep this after arch Makefile is included NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) CHECKFLAGS += $(NOSTDINC_FLAGS)
Arnd Bergmann reported: "When ftrace is enabled and we build with gcc-4.7 or older, we get a warning for each file on architectures that select CONFIG_LD_DEAD_CODE_DATA_ELIMINATION: warning: -ffunction-sections disabled; it makes profiling impossible [enabled by default] " Since commit c3f0d0bc5b01 ("kbuild, LLVMLinux: Add -Werror to cc-option to support clang"), warnings are treated as errors in cc-option checks. CC_FLAGS_FTRACE is blindly added to KBUILD_CFLAGS, so $(call cc-option,-ffunction-sections,) should be moved below it in order to detect the conflict between the two options. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- Makefile | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)