Linux-5.9: Remove CC_FLAGS_USING via asflags-remove

Linux-5.9: Remove CC_FLAGS_USING via asflags-remove

[Sedat Dilek]

Hi,

I wanted to get rid of CC_FLAGS_USING in lib/Makefile:

ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
+ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)
+asflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)

...it makes no sense to me to remove CC_FLAGS_FTRACE and not CC_FLAGS_USING.

ccflags-remove-y (here: CONFIG_FUNCTION_TRACER=y) seems  to work but
*not* asflags-remove-y.

Am I missing something?
It is getting overridden?

Documentation/kbuild/makefiles.rst says:
"...AFLAGS_$@ has the higher priority than asflags-remove..."

How can I check if there is another AFLAGS_XXX interfering?

I see -DCC_XXX in...

lib/.crc-t10dif.mod.o.cmd
lib/.crc-t10dif.o.cmd

I want to remove all -DCC_XXX assembler-options derived from lib/Makefile.

Regards,
- Sedat -

Re: Linux-5.9: Remove CC_FLAGS_USING via asflags-remove

[Masahiro Yamada]

On Sun, Oct 4, 2020 at 10:29 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> Hi,
>
> I wanted to get rid of CC_FLAGS_USING in lib/Makefile:
>
> ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
> +ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)
> +asflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)
>
> ...it makes no sense to me to remove CC_FLAGS_FTRACE and not CC_FLAGS_USING.
>
> ccflags-remove-y (here: CONFIG_FUNCTION_TRACER=y) seems  to work but
> *not* asflags-remove-y.
>
> Am I missing something?
> It is getting overridden?
>
> Documentation/kbuild/makefiles.rst says:
> "...AFLAGS_$@ has the higher priority than asflags-remove..."
>
> How can I check if there is another AFLAGS_XXX interfering?
>
> I see -DCC_XXX in...
>
> lib/.crc-t10dif.mod.o.cmd
> lib/.crc-t10dif.o.cmd


This is compiled from a C source file.

lib/crc-t10dif.c



Why are you trying asflags-remove-y for lib/Makefile?

I see no assembly source file under lib/.

masahiro@oscar:~/ref/linux$ find  lib  -name  '*.S'
masahiro@oscar:~/ref/linux$







> I want to remove all -DCC_XXX assembler-options derived from lib/Makefile.
>
> Regards,
> - Sedat -



-- 
Best Regards
Masahiro Yamada

Re: Linux-5.9: Remove CC_FLAGS_USING via asflags-remove

[Sedat Dilek]

On Sun, Oct 4, 2020 at 4:04 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Sun, Oct 4, 2020 at 10:29 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
> >
> > Hi,
> >
> > I wanted to get rid of CC_FLAGS_USING in lib/Makefile:
> >
> > ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)
> > +ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)
> > +asflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_USING)
> >
> > ...it makes no sense to me to remove CC_FLAGS_FTRACE and not CC_FLAGS_USING.
> >
> > ccflags-remove-y (here: CONFIG_FUNCTION_TRACER=y) seems  to work but
> > *not* asflags-remove-y.
> >
> > Am I missing something?
> > It is getting overridden?
> >
> > Documentation/kbuild/makefiles.rst says:
> > "...AFLAGS_$@ has the higher priority than asflags-remove..."
> >
> > How can I check if there is another AFLAGS_XXX interfering?
> >
> > I see -DCC_XXX in...
> >
> > lib/.crc-t10dif.mod.o.cmd
> > lib/.crc-t10dif.o.cmd
>
>
> This is compiled from a C source file.
>
> lib/crc-t10dif.c
>
>
>
> Why are you trying asflags-remove-y for lib/Makefile?
>
> I see no assembly source file under lib/.
>
> masahiro@oscar:~/ref/linux$ find  lib  -name  '*.S'
> masahiro@oscar:~/ref/linux$
>

Yeah, you are right it is a C file.

It looks like CC_FLAGS_USING is not "inherited" or passed or whatever.

I tried with "filter-out" and...

KBUILD_CFLAGS := $(filter-out -DCC_USING_FENTRY, $(KBUILD_CFLAGS)

....that resulted in an error:

need-builtin= \
need-modorder=1
In file included from lib/bug.c:50:
In file included from ./include/linux/ftrace.h:21:
./arch/x86/include/asm/ftrace.h:7:3: error: Compiler does not support fentry?
# error Compiler does not support fentry?
  ^
1 error generated.
make[4]: *** [scripts/Makefile.build:276: lib/bug.o] Error 1

So, it looks like I was wrong with removing -DCC_USING_XXX.

Thanks for the quick response.

- Sedat -


>
> > I want to remove all -DCC_XXX assembler-options derived from lib/Makefile.
> >
> > Regards,
> > - Sedat -
>
>
>
> --
> Best Regards
> Masahiro Yamada

Re: Linux-5.9: Remove CC_FLAGS_USING via asflags-remove

[Sedat Dilek]

Both work.

[ lib/Makefile ]

ccflags-remove-$(CONFIG_FUNCTION_TRACER) += $(CC_FLAGS_FTRACE)

#1:
ccflags-remove-$(CONFIG_FUNCTION_TRACER) += -DCC_USING_NOP_MCOUNT

#2:
KBUILD_CFLAGS := $(filter-out -DCC_USING_NOP_MCOUNT, $(KBUILD_CFLAGS))

- Sedat -