Re: [PATCH] arm64: remove redundant 'if HAVE_ARCH_KASAN' in Kconfig

[Masahiro Yamada]

On Mon, Jul 15, 2024 at 10:44 PM Mark Rutland <mark.rutland@xxxxxxx> wrote:
>
> On Mon, Jul 15, 2024 at 08:11:08AM +0530, Anshuman Khandual wrote:
> > On 7/14/24 16:28, Masahiro Yamada wrote:
> > > The condition 'select HAVE_ARCH_KASAN' is always true because
> > > there is 'select HAVE_ARCH_KASAN' statement above.
> > >
> > > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > > ---
> > >
> > >  arch/arm64/Kconfig | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > > index c87d16b12e9b..d37cbfc3031e 100644
> > > --- a/arch/arm64/Kconfig
> > > +++ b/arch/arm64/Kconfig
> > > @@ -167,9 +167,9 @@ config ARM64
> > >     select HAVE_ARCH_JUMP_LABEL
> > >     select HAVE_ARCH_JUMP_LABEL_RELATIVE
> > >     select HAVE_ARCH_KASAN
> > > -   select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
> > > -   select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
> > > -   select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
> > > +   select HAVE_ARCH_KASAN_VMALLOC
> > > +   select HAVE_ARCH_KASAN_SW_TAGS
> > > +   select HAVE_ARCH_KASAN_HW_TAGS if ARM64_MTE
> > >     # Some instrumentation may be unsound, hence EXPERT
> > >     select HAVE_ARCH_KCSAN if EXPERT
> > >     select HAVE_ARCH_KFENCE
> >
> > There is another similar instance with HAVE_FUNCTION_GRAPH_TRACER as well.
> > Just wondering if the following change should be folded in here ?
> >
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -210,8 +210,8 @@ config ARM64
> >         select HAVE_FTRACE_MCOUNT_RECORD
> >         select HAVE_FUNCTION_TRACER
> >         select HAVE_FUNCTION_ERROR_INJECTION
> > -       select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER
> >         select HAVE_FUNCTION_GRAPH_TRACER
> > +       select HAVE_FUNCTION_GRAPH_RETVAL
> >         select HAVE_GCC_PLUGINS
> >         select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && \
> >                 HW_PERF_EVENTS && HAVE_PERF_EVENTS_NMI
>
> That looks like a sensible cleanup, but I think it'd be better as a
> separate patch.
>
> It looks like that has always been redundant since it was introduced in
> commit
>
>   3646970322464c21 ("arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL")
>
> ... would you mind spinning a patch?
>
> Mark.


Agree.

We can have a separate patch.


I can see more redundant 'if' and 'depends on'.


For example, KERNEL_MODE_NEON is always 'y'.

config KERNEL_MODE_NEON
     def_bool y



So, I can see redundancy in


     select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON

and

     config EFI
          bool "UEFI runtime support"
          depends on OF && !CPU_BIG_ENDIAN
          depends on KERNEL_MODE_NEON




-- 
Best Regards
Masahiro Yamada