linux-kernel - Re: [PATCH] drm/amd/display: Support clang option for stack alignment

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Message-ID: <CAKwvOd=Xdp_=G3UU9ubayeTvkKCJ9hak0a-7yK90-RPUBQKrpw@mail.gmail.com>
Date:   Fri, 12 Jul 2019 11:49:05 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Harry Wentland <harry.wentland@....com>,
        Leo Li <sunpeng.li@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Dmytro Laktyushkin <Dmytro.Laktyushkin@....com>,
        Duke Du <Duke.Du@....com>, Charlene Liu <charlene.liu@....com>,
        amd-gfx@...ts.freedesktop.org,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Matthias Kaehlcke <mka@...gle.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>
Subject: Re: [PATCH] drm/amd/display: Support clang option for stack alignment

On Fri, Jul 12, 2019 at 2:37 AM Arnd Bergmann <arnd@...db.de> wrote:
>
> As previously fixed for dml in commit 4769278e5c7f ("amdgpu/dc/dml:
> Support clang option for stack alignment") and calcs in commit
> cc32ad8f559c ("amdgpu/dc/calcs: Support clang option for stack
> alignment"), dcn20 uses an option that is not available with clang:
>
> clang: error: unknown argument: '-mpreferred-stack-boundary=4'
> scripts/Makefile.build:281: recipe for target 'drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_resource.o' failed
>
> Use the same trick that we have in the other two files.

Maybe time for a macro in Kbuild.include or some such, if we see this
pattern being repeated?

>
> Fixes: 7ed4e6352c16 ("drm/amd/display: Add DCN2 HW Sequencer and Resource")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  drivers/gpu/drm/amd/display/dc/dcn20/Makefile |  8 +++++++-
>  drivers/gpu/drm/amd/display/dc/dsc/Makefile   | 16 ++++++++++++----
>  2 files changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> index 1b68de27ba74..e9721a906592 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> @@ -10,7 +10,13 @@ ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
>  DCN20 += dcn20_dsc.o
>  endif
>
> -CFLAGS_dcn20_resource.o := -mhard-float -msse -mpreferred-stack-boundary=4
> +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
> +       cc_stack_align := -mpreferred-stack-boundary=4
> +else ifneq ($(call cc-option, -mstack-alignment=16),)
> +       cc_stack_align := -mstack-alignment=16
> +endif
> +
> +CFLAGS_dcn20_resource.o := -mhard-float -msse $(cc_stack_align)
>
>  AMD_DAL_DCN20 = $(addprefix $(AMDDALPATH)/dc/dcn20/,$(DCN20))
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
> index c5d5b94e2604..e019cd9447e8 100644
> --- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
> @@ -1,10 +1,18 @@
>  #
>  # Makefile for the 'dsc' sub-component of DAL.
>
> -CFLAGS_rc_calc.o := -mhard-float -msse -mpreferred-stack-boundary=4
> -CFLAGS_rc_calc_dpi.o := -mhard-float -msse -mpreferred-stack-boundary=4
> -CFLAGS_codec_main_amd.o := -mhard-float -msse -mpreferred-stack-boundary=4
> -CFLAGS_dc_dsc.o := -mhard-float -msse -mpreferred-stack-boundary=4
> +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
> +       cc_stack_align := -mpreferred-stack-boundary=4
> +else ifneq ($(call cc-option, -mstack-alignment=16),)
> +       cc_stack_align := -mstack-alignment=16
> +endif
> +
> +dsc_ccflags := -mhard-float -msse $(cc_stack_align)
> +
> +CFLAGS_rc_calc.o := $(dsc_ccflags)
> +CFLAGS_rc_calc_dpi.o := $(dsc_ccflags)
> +CFLAGS_codec_main_amd.o := $(dsc_ccflags)
> +CFLAGS_dc_dsc.o := $(dsc_ccflags)
-- 
Thanks,
~Nick Desaulniers